Risks of Esfenvalerate Use to Federally Threatened
California Red-Legged Frog
(Rana aurora draytonii)
Pesticide Effects Determination
Environmental Fate and Effects Division
Office of Pesticide Programs
Washington, D.C. 20460
February 19, 2008
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Primary Authors
Shannon Borges, Biologist
Katrina White, Ph.D., Biologist
Nelson Thurman, Senior Fate Scientist
Environmental Risk Branch II
Environmental Fate and Effects Division (7507P)
Secondary Review
Donna Randall, Senior Effects Scientist
Environmental Risk Branch II
Environmental Fate and Effects Division (7507P)
Dana Spatz, Acting Branch Chief,
Environmental Risk Branch II
Environmental Fate and Effects Division (7507P)
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Table of Contents
1.0 Executive Summary 1
2.0 Problem Formulation 7
2.1 Purpose 7
2.2 Scope 9
2.3 Previous Assessments 10
2.4 Stressor Source and Distribution 10
2.4.1 Environmental Fate Properties 10
2.4.2 Environmental Transport Mechanisms 20
2.4.3 Mechanism of Action 21
2.4.4 Use Characterization 21
2.5 Assessed Species 33
2.5.1 Distribution 33
2.5.2 Reproduction 39
2.5.3 Diet 39
2.5.4 Habitat 40
2.6 Designated Critical Habitat 41
2.7 Action Area 43
2.8 Assessment Endpoints and Measures of Ecological Effect 44
2.8.1 Assessment Endpoints for the CRLF 44
2.8.2 Assessment Endpoints for Designated Critical Habitat 46
2.9 Conceptual Model 49
2.9.1 Risk Hypotheses 49
2.9.2 Diagram 50
2.10 Analysis Plan 55
2.10.1 Measures to Evaluate the Risk Hypotheses and Conceptual Model 55
3.0 Exposure Assessment 60
3.1 Label Application Rates and Intervals 60
3.2 Aquatic Exposure Assessment 63
3.2.1 Modeling Approach 63
3.2.2 Model Inputs 65
3.2.3 Results 68
3.2.4 Existing Monitoring Data 68
3.3 Terrestrial Animal Exposure Assessment 74
3.4 Terrestrial Plant Exposure Assessment 76
4.0 Effects Assessment 77
4.1 Evaluation of Aquatic Ecotoxicity Studies 80
4.1.1 Toxicity to Amphibians 80
4.1.2 Toxicity to Freshwater Fish 81
4.1.3 Toxicity to Freshwater Invertebrates 83
4.1.4 Toxicity to Aquatic Plants 86
4.1.5 Freshwater Field Studies 86
4.2 Evaluation of Terrestrial Ecotoxicity Studies 88
4.2.1 Toxicity to Birds 88
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4.2.2 Toxicity to Mammals 89
4.2.3 Toxicity to Non-Target Terrestrial Invertebrates 91
4.2.4 Toxicity to Terrestrial Plants 91
4.3 Use of Probit Slope Response Relationship to Provide Information on the
Endangered Species Levels of Concern 92
4.4 Incident Database Review 93
5.0 Risk Characterization 96
5.1 Risk Estimation 96
5.1.1 Exposures in the Aquatic Habitat 96
5.1.2 Exposures in the Terrestrial Habitat 101
5.1.3 Primary Constituent Elements of Designated Critical Habitat 105
5.2 Risk Description 105
5.2.1 Direct Effects 108
5.2.2 Indirect Effects to the CRLF (via reductions in prey base) 110
5.2.3 Indirect Effects (via Habitat Effects) 112
5.2.4 Modification of Designated Critical Habitat 113
5.3 Risk Hypotheses Revisited 113
6.0 Uncertainties 116
6.1 Exposure Assessment Uncertainties 116
6.1.1 Maximum Use Scenario 116
6.1.2 Aquatic Exposure Modeling of Esfenvalerate 116
6.1.3 Action Area Uncertainties 118
6.1.4 Usage Uncertainties 118
6.1.5 Terrestrial Exposure Modeling of Esfenvalerate 118
6.1.6 Spray Drift Modeling 119
6.2 Effects Assessment Uncertainties 120
6.2.1 Age Class and Sensitivity of Effects Thresholds 120
6.2.2 Use of Surrogate Species Effects Data 120
6.2.3 Sublethal Effects 120
6.2.4 Location of Wildlife Species 121
7.0 Risk Conclusions 122
8.0 References 125
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Appendices
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
APPENDIX F
APPENDIX G
APPENDIX H
APPENDIX I
APPENDIX J
APPENDIX K
APPENDIX L
APPENDIX M
Product Formulations Containing Multiple Active Ingredients
PRZM/EXAMS Modeling Results
Estimated Exposures and Risk Quotients for Terrestrial Environments (T-
REX and T-HERPS)
Papers accepted for ECOTOX-OPP and Included
Papers accepted for ECOTOX-OPP but Not Included
Papers Excluded from ECOTOX (Without Abstracts)
Pounds Esfenvalerate Applied per Month in 2005 for Select Crops in
California
Listing of Applicable Labels for Each Crop/Use Grouping
Total Pounds Applied in Each County for the Years 2002-2005
Summary of Esfenvalerate Half Lives in Soil
Post Processing of Residential and Rights-of-way Scenarios to Estimate
Aquatic EECs
Toxicity Categories and Levels of Concern
Open Literature Review Summaries for Included ECOTOX Papers
Attachment 1
Status and Life History of the California Red Legged Frog
IV
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List of Tables
Table 1-1. Effects Determination Summary for Direct and Indirect Effects of Esfenvalerate on
the CRLF and Effects to its Designated Critical Habitat 4
Table 2-1. Summary of Physico-Chemical Properties of Esfenvalerate 12
Table 2-2. Summary of Esfenvalerate Environmental Fate Properties 18
Table 2-3. Labeled Agricultural Uses Assessed in this Document.1 22
Table 2-4. Labeled Non-agricultural Uses Assessed in this Document.1'2 25
Table 2-5. Labeled Non- agricultural Uses Qualitatively Assessed in this Document 26
Table 2-6. Summary of California Department of Pesticide Registration (CDPR) Pesticide Use
Reporting (PUR) Data from 2002 to 2005 for Currently Registered Esfenvalerate
Uses.1 29
Table 2-7. California Red-legged Frog Recovery Units with Overlapping Core Areas and
Designated Critical Habitat 35
Table 2-8. Summary of Assessment Endpoints and Measures of Ecological Effects for Direct
and Indirect Effects of Esfenvalerate on the CRLF 45
Table 2-9. Summary of Assessment Endpoints and Measures of Ecological Effect for Primary
Constituent Elements of Designated Critical Habitat 47
Table 3-1. Esfenvalerate Uses, Scenarios, and Application Information for Estimating Aquatic
Environmental Concentrations.l'2 61
Table 3-2. Summary of PRZM/EZAMS Environmental Fate Data Used for Aquatic Exposure
Inputs for Esfenvalerate Endangered Species Assessment for the CRLF.1'2 65
Table 3-3. PRZM/EXAMS Scenarios Used to Estimate Concentrations of Esfenvalerate in the
Aquatic Environment.1 67
Table 3-4. Aquatic EECs (|ig/L) for Esfenvalerate Uses in California.1 70
Table 3-5. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for
Esfenvalerate with T-REX 74
Table 3-6.Upper-Bound Kenaga Nomogram EECs for Dietary- and Dose-based Exposures of the
CRLF and its Small Mammalian Prey to Esfenvalerate 75
Table 3-7. EECs (ppm) for Indirect Effects to the Terrestrial-Phase CRLF via Effects to
Terrestrial Invertebrate Prey Items 76
Table 4-1. Summary of Esfenvalerate Toxicity Data Used to Assess Direct Effects, Indirect
Effects, and Adverse Modification to Critical Habitat for the CRLF 78
Table 4-2. Acute Toxicity of Esfenvalerate to Freshwater Fish 82
Table 4-3. Chronic Toxicity of Esfenvalerate to Freshwater Fish 82
Table 4-4. Acute Toxicity of Esfenvalerate to Freshwater Invertebrates 84
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Table 4-5. Chronic Toxicity of Esfenvalerate to Freshwater Invertebrates 85
Table 4-6. Acute Oral and Subacute Dietary Toxicity of Esfenvalerate to Birds 88
Table 4-7. Toxicity of Esfenvalerate to Mammals 90
Table 4-8. Chronic Toxicity of Esfenvalerate to Mammals 90
Table 4-9. Toxicity of Esfenvalerate to Non-Target Terrestrial Insects 91
Table 5-1. RQs for Determination of Direct Effects to the Aquatic-Phase CRLF 97
Table 5-2. RQs for Determination of Indirect Effects to the Aquatic-Phase CRLF Through Loss
of Aquatic Invertebrate Food Base 99
Table 5-3. Dietary- and Dose-Based Acute RQs for Determination of Direct Effects to the
Terrestrial-Phase CRLF 101
Table 5-4. RQs for Terrestrial Invertebrates for Determination of Indirect Effects to the
Terrestrial-Phase CRLF 103
Table 5-5. RQs for Terrestrial Mammals for Determination of Indirect Effects to the Terrestrial-
Phase CRLF 104
Table 5-6. Preliminary Effects Determination Summary for Esfenvalerate - Direct and Indirect
Effects to the CRLF 106
Table 5-7. Risk Hypothesis Revisited 113
Table 7-1. Effects Determination Summary for Direct and Indirect Effects of Esfenvalerate on
the CRLF 122
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List of Figures
Figure 2-1. Chemical Structures of Esfenvalerate and Related Compounds 11
Figure 2-2. Proposed Photodegradation Pathway of Esfenvalerate on Soil, Clay Mineral, and
Humic Acid Surfaces based on Katagi 1991 and 1994. x'2 16
Figure 2-3. Average Total Pounds Applied in Each County for the Years 2002-2005. Counties
applying on average more than 500 pounds per year were included in the figure 28
Figure 2-4. Comparison of phases of the California Red-legged Frog (CRLF) life cycle to the
average pounds esfenvalerate applied per month between 2003 and 2005 31
Figure 2-5. Timing of Esfenvalerate Application: Average number of pounds of active
ingredient applied in California for Almond and Peach, per month, between January
2002 through December 2005. Similar figures for other crops are available in 32
Figure 2-6. Pounds of Esfenvalerate Applied Each Year by Crop 33
Figure 2-7. Recovery Unit, Core Area, Critical Habitat, and Occurrence Designations for CRLF
38
Figure 2-8. CRLF Reproductive Events by Month 39
Figure 2-9. Conceptual Model for Pesticide Effects on Aquatic-Phase of the CRLF 51
Figure 2-10. Conceptual Model for Pesticide Effects on Terrestrial-Phase of the CRLF 52
Figure 2-11. Conceptual Model for Pesticide Effects on Aquatic Components of CRLF Critical
Habitat 53
Figure 2-12. Conceptual Model for Pesticide Effects on Terrestrial Components of the CRLF
Critical Habitat 54
Figure 3-1. Total Pounds of Esfenvalerate Applied to Almonds by Month in 2005 based on
CDPR PUR data 68
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1.0 Executive Summary
The purpose of this assessment is to evaluate potential direct and indirect effects on the
California red-legged frog (Rana aurora draytonii) (CRLF) arising from FIFRA regulatory
actions regarding use of esfenvalerate on agricultural and non-agricultural sites. In addition, this
assessment evaluates whether these actions can be expected to result in modification of the
species' designated critical habitat. This assessment was completed in accordance with the U.S.
Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) Endangered
Species Consultation Handbook (USFWS/NMFS, 1998) and procedures outlined in the
Agency's Overview Document (U.S. EPA, 2004).
The CRLF was listed as a threatened species by USFWS in 1996. The species is endemic to
California and Baja California (Mexico) and inhabits both coastal and interior mountain ranges.
A total of 243 streams or drainages are believed to be currently occupied by the species, with the
greatest numbers in Monterey, San Luis Obispo, and Santa Barbara counties (USFWS, 1996) in
California.
Esfenvalerate is an insecticide that has a variety of agricultural and non-agricultural uses, and is
used both indoors and outdoors. Currently, there are over 150 labeled uses of esfenvalerate. An
extensive list of these uses is provided in Section 2.4.4, as well as extensive lists of agricultural
uses (see Table 2-3), non-agricultural uses (see Table 2-4), and uses qualitatively assessed in this
document (see Table 2-6). A list of the uses that are considered as part of the federal action
evaluated in this assessment includes: almonds, filberts, pecans, walnuts, broccoli, Chinese
broccoli, cabbage, Chinese cabbage, cauliflower, collards, kohlrabi, mustard, corn (unspecified,
pop, field, sweet), sunflower, apple, apricot, cherry, nectarine, peach, pear, plum, prune,
cucumber, eggplant, melon (unspecified, cantaloupe, honeydew, musk, water), pumpkin, squash
(unspecified, summer, winter), potato, turnip, artichoke, beans (dried, succulent), carrot, lentils,
peas (unspecified, dried), pepper, sugar beet, cotton, kiwi, head lettuce, peanuts, radish,
sugarcane, sorghum, tomato, Christmas trees, conifer plantations, seed orchards, forest tree
nurseries, non-cropland, forest trees, softwoods, conifers, general outdoor surfaces, building
perimeters, home and garden, lawn and grass, automobiles, kennels and animal housing areas,
ant mounds and wasp and hornet nests, and mosquito breeding areas.
Available environmental fate data indicate that esfenvalerate is relatively stable to hydrolysis,
with aerobic or anaerobic metabolism being the major pathways of degradation in soils and
sediment. Under some conditions, photolysis may also be an important degradation pathway
(Katagil 1991; Katagi 1993; Castle et al. 1990, MRID 41728501). Esfenvalerate is relatively
insoluble in water, isn't likely to volatilize, and, with a high K0c, has a high tendency to sorb to
soil and sediment. Major off site transport pathways for esfenvalerate will be spray drift during
application and runoff, primarily sorbed to sediment. Esfenvalerate will persist in some
environments, especially soils and sediments. A complete discussion of the environmental fate
data is provided in Section 2.4.
Esfenvalerate consists of four stereoisomers (SS, RS, SR, RR); the active ingredient is enriched
with the SS-isomer (75-90%) (Solomon et al. 2001; ATSDR 1993). In water, the SS-isomer may
sterioisomerize into the RS and SR-isomers (Lee 1989, MRID 00146578). However, since the
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SS-isomer is the most toxic to insects and data specific to the other individual isomers is limited,
aquatic concentrations were estimated for the combined isomers and assumed toxicity equivalent
to the more potent insecticidal SS-isomer (ATSDR 2003; Adelsbach et al. 2003; Eisler 1992).
No degradates are included in the exposure assessment as the only major aerobic and anaerobic
degradate was carbon dioxide (Gaddamidi et al. 1992, MRID 42396801; Lee et al. 1985, MRID
00146578). Primary photolysis degradation products included carbon dioxide, 3-phenoxybenzyl
alcohol, 3-phenoxybenzoic acid, and alpha-carbamoyl-3-phenoxybenzyl 2-(4-chlorophenyl)-3-
methylbutyrate (Katagi 1991; Katagi 1993; Castle etal. 1990, MRID 41728502). Degradation
results in the breakage of the ester bond in the pyrethroid structure and the resulting degradates
are not expected to add significantly to risk estimates based on esfenvalerate residues.
Monitoring data are available from the California Department of Pesticide Regulation (CDPR)
for esfenvalerate in surface water and sediments. In surface water, esfenvalerate was detected in
0.8% of samples with concentrations ranging from 0.06 to 0.17 |j,g/L (CDPR, available at
http://www.cdpr.ca.gov/docs/sw/surfdata.htm). CDPR also found esfenvalerate in 8% of
sediment samples with concentrations ranging from 0.002 to 0.07 (ig/g (ppm), or 20 to 70 ng/g
(ppb). Weston et al. (2004) found esfenvalerate in 32% of sediment samples collected from the
Central Valley of California with concentrations ranging from 10 to 30 ng/g (ppb). A complete
discussion of the monitoring data is provided in Section 3.2.4.
Since CRLFs exist within aquatic and terrestrial habitats, exposure of the CRLF, its prey and its
habitats to esfenvalerate are assessed separately for the two habitats. Tier-II aquatic exposure
models are used to estimate high-end exposures of esfenvalerate in aquatic habitats resulting
from runoff and spray drift from different uses. Peak model-estimated environmental
concentrations resulting from different esfenvalerate uses range from 0.017 to 6.46 |ig/L in the
water column. These estimates are supplemented with analysis of available California surface
water and sediment monitoring data from the CDPR. The maximum concentration of
esfenvalerate reported by the CDPR surface water database from 2000-2005 (0.17 |ig/L) is
roughly 50 times lower than the highest peak model-estimated environmental concentration.
To estimate esfenvalerate exposures to the terrestrial-phase CRLF, and its potential prey
resulting from uses involving esfenvalerate applications, the T-REX model is used mainly for
aerial and ground spray applications. The AgDRIFT model is also used to estimate deposition of
esfenvalerate on terrestrial and aquatic habitats from spray drift. The T-HERPS model is used to
allow for further characterization of dose-based exposures of terrestrial-phase CRLFs relative to
screening exposure estimates based on birds in T-REX.
The assessment endpoints for the CRLF include direct toxic effects on survival, reproduction,
and growth, as well as indirect effects, such as reduction of the prey base or modification of its
habitat. Direct effects to the CRLF in the aquatic habitat are based on toxicity information for
freshwater fish, which are used as a surrogate for aquatic-phase amphibians when no amphibian
data is available. In the terrestrial habitat, direct effects are based on toxicity information for
birds, which are used here as a surrogate for terrestrial-phase amphibians. Given that the CRLF's
prey items and primary constituent elements (PCEs) of designated critical habitat include or are
dependent on the availability of freshwater aquatic invertebrates and aquatic plants, toxicity
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information for these taxonomic groups is also discussed. In the terrestrial habitat, indirect
effects to the CRLF and effects to PCEs of designated critical habitat due to depletion of prey are
assessed by considering effects to terrestrial insects, small terrestrial mammals, and frogs.
Indirect effects and effects to PCEs of critical habitat due to modification of the terrestrial habitat
are characterized by available data for terrestrial monocots and dicots; however, only
information from the open literature is available by which to qualitatively discuss potential risks
to plants. These are described.
Risk quotients (RQs), which are ratios of exposure estimates to appropriate toxicity measurement
endpoints are used as estimates of potential risk in this assessment. Acute and chronic RQs are
compared to the Agency's acute and chronic levels of concern (LOCs), respectively, to identify
instances where esfenvalerate use within the action area has the potential to affect the CRLF and
its designated critical habitat via direct toxicity or indirectly based on effects to its food supply
{i.e., freshwater invertebrates, algae, fish, frogs, terrestrial invertebrates, and mammals) or
habitat {i.e., aquatic plants and terrestrial upland and riparian vegetation) and the potential to
affect PCEs of its designated critical habitat. When a RQ is below its respective LOC, the
pesticide is determined to have "no effect" and where a RQ exceeds its respective LOC, a
potential to cause effects is identified. One or more exceedances are used to draw a conclusion
of "may affect." If a determination is made that use of esfenvalerate within the action area "may
affect" the CRLF and its designated critical habitat, additional information is considered to refine
the potential for exposure and effects, and the best available information is used to distinguish
those actions that "may affect, but are not likely to adversely affect" (NLAA) from those actions
that are "likely to adversely affect" (LAA) the CRLF and its designated critical habitat.
For indoor uses, a qualitative assessment rather than a quantitative approach with RQ
calculations was performed. For indoor uses of esfenvalerate, exposure pathways to the CRLF or
its designated critical habitat are incomplete and these uses of esfenvalerate were determined to
have "No Effect" on the CRLF or its designated critical habitat. Indoor uses include:
• Interior vehicle uses (vehicles, boats, campers, railroad cars, truck trailers)
• Indoor uses: commercial, residential, and industrial buildings, grain storage facilities,
cadavers and caskets, voids in equipment and structures, grain storage facilities
For the remainder of esfenvalerate uses, based on the best available information, the Agency
makes a Likely to Adversely Affect determination for the CRLF. Additionally, the Agency has
determined that there is the potential for modification of CRLF designated critical habitat from
the use of the chemical. Direct effects are expected to the aquatic-phase CRLF as a result of
acute risks for all uses, but also as a result of chronic risks for uses with high application rates.
Indirect effects to the CRLF and effects to its designated critical habitat are also expected as a
result of reduction in aquatic invertebrate, fish, and amphibian prey base. EFED does not have
data to quantitatively assess risk to aquatic or terrestrial plants. However, based on indirect or
supplemental evidence, adverse effects are not expected to occur as a result of losses of aquatic
or terrestrial plants that provide food and/or habitat. Direct effects to the terrestrial-phase CRLF
are expected due to acute risk to the CRLF as a result of uses with relatively high single
application rates and/or high numbers of applications. Data are not available to reliably quantify
chronic risk, but based on supplemental data for fenvalerate (made up of approximately equal
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amounts of the SS, SR, RS, and RR isomers), chronic risk is expected to occur for these uses as
well. However, since these cannot be determined, our conservative conclusion is that direct
effects may occur as a result of all uses. Indirect effects to the terrestrial-phase CRLF and its
critical habitat are expected as a result of reductions in the terrestrial invertebrate, mammalian,
and amphibian prey base. As with aquatic plants, data are not available to quantitatively assess
effects to terrestrial plants; however, qualitative information in the open literature suggests that
risk to terrestrial plants should not be expected at current label rates.
A summary of the risk conclusions and effects determinations for the CRLF and its designated
critical habitat is presented in Table 1-1. Since data are not available to quantify plant risks and
risk to plants is not expected; effects on critical habitat are expected to be the same as those
identified for indirect effects to the CRLF. Use-specific determinations for direct and indirect
effects to the CRLF are not provided, as our conclusions are applicable to each use. Further
information on the results of the effects determination is included as part of the Risk Description
in Section 5.2.
Table 1-1. Effects Determination Summary for Direct and Indirect Effects of Esfenvalerate
on the CRLF and Effects to its Designated Critical Habitat.
Assessment Endpoint
Effects
Determination1
Basis for Determination
Aquatic-Phase CRLF
(Eggs, Larvae, and Adults)
Direct Effects:
Survival, growth, and reproduction of
CRLF individuals via direct effects on
aquatic phases
Likely to Adversely
Affect
Acute LOCs for direct effects to the CRLF are exceeded
for all uses and application rates. Uses that require high
numbers of applications, regardless of their maximum
single application rate, also result in direct chronic risk to
the aquatic-phase CRLF. Probability of individual acute
mortality was determined to be high based on RQs and
the slope of dose-response. Incidents indicate potential
for mortality with exposure to runoff following labeled
uses. Exposure is expected in all areas occupied by
CRLF.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects to food
supply (i.e., freshwater invertebrates,
non-vascular plants, fish, and frogs)
Freshwater
invertebrates, fish,
and other amphibians:
Likely to Adversely
Affect
Acute LOCs for aquatic invertebrates, fish, and other
amphibians are exceeded for aquatic animals for all uses
and application rates. The probability of mortality is
high for aquatic invertebrates and fish. Uses that require
high numbers of applications also result in chronic risk to
these taxa.
Non-vascular aauatic
olants: Not Likelv to
Adversely Effect
Indirect effects resulting from losses of aquatic vascular
and non-vascular plants as a food source or as a habitat
component are not expected for current label rates based
on supplemental information gathered in a mesocosm
study submitted to OPP and from the field studies.
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Assessment Endpoint
Effects
Determination1
Basis for Determination
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat, cover, and/or primary
productivity (i.e., aquatic plant
community)
Vascular and Non-
vascular aauatic
olants: NotLikelv
to Adversely Affect
Indirect effects resulting from losses of aquatic vascular
and non-vascular plants as a food source or as a habitat
component are not expected for current label rates
based on supplemental information gathered in a
mesocosm study submitted to OPP and from field
studies.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects to riparian
vegetation, required to maintain
acceptable water quality and habitat in
ponds and streams comprising the
species' current range.
Not Likely to
Adversely Affect
EFED does not have aquatic plant toxicity data to
estimate the risk to plants; however, based on studies
available in the ECOTOX database, effects on terrestrial
plants are expected to be unlikely.
Terrestrial-Phase CRLF
(Juveniles and adults)
Direct Effects:
Survival, growth, and reproduction of
CRLF individuals via direct effects on
terrestrial phase adults and juveniles
Likely to Adversely
Affect
Acute risk to the CRLF has been identified for uses
allowing numerous applications of 0.05 lbs ai/acre (e.g.,
forestry uses - 25 apps/year), multiple applications at
0.075 lbs ai/acre and 0.1 lbs ai/acre, or single
applications at higher rates. Estimated probability of
acute mortality for an individual is high. A conservative
conclusion is made that chronic effects may result from
all uses based on supplemental information and the
inability to quantitatively identify exposure levels that
would not result in chronic effects. Overlap of
esfenvalerate use is expected in all areas occupied by the
CRLF.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects on prey (i.e.,
terrestrial invertebrates, small terrestrial
vertebrates, including mammals and
terrestrial phase amphibians)
Terrestrial
invertebrates: Likelv
to Adversely Affect
Acute LOCs for small and large insects are exceeded in
all cases and the probability of an individual acute
mortality is high. Overlap of use is expected for all areas
occupied by the CRLF.
Mammals: Likelv to
Adversely Affect
The acute and chronic LOCs are exceeded for all but one
use and the probability of individual acute mortality is
high. Overlap of use is expected for all areas occupied
by the CRLF.
Fross: Likelv to
Adversely Affect
Since this conclusion was drawn for direct effects to the
CRLF, risk is also presumed for other amphibians.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat (i.e., riparian vegetation)
Not Likely to
Adversely Affect
EFED does not have aquatic plant toxicity data to
estimate the risk to plants; however, based on
supplemental information, effects on terrestrial plants are
expected to be unlikely at the current use rates.
Based on the conclusions of this assessment, a formal consultation with the U. S. Fish and
Wildlife Service under Section 7 of the Endangered Species Act should be initiated to seek
concurrence with the LAA determinations and to determine whether there are reasonable and
prudent alternatives and/or measures to reduce and/or eliminate potential incidental take.
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When evaluating the significance of this risk assessment's direct/indirect and habitat
modification effects determinations, it is important to note that pesticide exposures and predicted
risks to the species and its resources (i.e., food and habitat) are not expected to be uniform across
the action area. In fact, given the assumptions of drift and downstream transport (i.e., attenuation
with distance), pesticide exposure and associated risks to the species and its resources are
expected to decrease with increasing distance away from the treated field or site of application.
Evaluation of the implication of this non-uniform distribution of risk to the species would require
information and assessment techniques that are not currently available. Examples of such
information and methodology required for this type of analysis would include the following:
• Enhanced information on the density and distribution of CRLF life stages within
specific recovery units and/or designated critical habitat within the action area.
This information would allow for quantitative extrapolation of the present risk
assessment's predictions of individual effects to the proportion of the population
extant within geographical areas where those effects are predicted. Furthermore,
such population information would allow for a more comprehensive evaluation of
the significance of potential resource impairment to individuals of the species.
• Quantitative information on prey base requirements for individual aquatic- and
terrestrial-phase frogs. While existing information provides a preliminary picture
of the types of food sources utilized by the frog, it does not establish minimal
requirements to sustain healthy individuals at varying life stages. Such
information could be used to establish biologically relevant thresholds of effects
on the prey base, and ultimately establish geographical limits to those effects.
This information could be used together with the density data discussed above to
characterize the likelihood of adverse effects to individuals.
• Information on population responses of prey base organisms to the pesticide.
Currently, methodologies are limited to predicting exposures and likely levels of
direct mortality, growth or reproductive impairment immediately following
exposure to the pesticide. The degree to which repeated exposure events and the
inherent demographic characteristics of the prey population play into the extent to
which prey resources may recover is not predictable. An enhanced understanding
of long-term prey responses to pesticide exposure would allow for a more refined
determination of the magnitude and duration of resource impairment, and together
with the information described above, a more complete prediction of effects to
individual frogs and potential modification to critical habitat.
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2.0 Problem Formulation
Problem formulation provides a strategic framework for the risk assessment. By identifying the
important components of the problem, it focuses the assessment on the most relevant life history
stages, habitat components, chemical properties, exposure routes, and endpoints. The structure
of this risk assessment is based on guidance contained in U.S. EPA's Guidance for Ecological
Risk Assessment (U.S. EPA 1998), the Services' Endangered Species Consultation Handbook
(USFWS/NMFS 1998) and is consistent with procedures and methodology outlined in the
Overview Document (U.S. EPA 2004) and reviewed by the U.S. Fish and Wildlife Service and
National Marine Fisheries Service (USFWS/NMFS 2004).
2.1 Purpose
The purpose of this endangered species assessment is to evaluate potential direct and indirect
effects on individuals of the federally threatened California red-legged frog (Rana aurora
draytonii) (CRLF) arising from FIFRA regulatory actions regarding use of esfenvalerate on a
variety of agricultural (fruit and nut trees, corn, cole crops, melons, potatoes, and other
vegetables) forestry, nursery, home and garden, and indoor/outdoor residential, commercial, and
industrial uses (see Table 2-3, 2-4, and 2-5 for a detailed list of uses).
In addition, this assessment evaluates whether these actions can be expected to result in the
modification of the species' designated critical habitat. Key biological information for the CRLF
is included in Section 2.5, and designated critical habitat information for the species is provided
in Section 2.6 of this assessment. This ecological risk assessment has been prepared consistent
with a settlement agreement in the case Center for Biological Diversity (CBD) us. EPA et al.
(Case No. 02-1580-JSW(JL)) settlement entered in Federal District Court for the Northern
District of California on October 20, 2006.
In this assessment, direct and indirect effects to the CRLF and potential modification to its
designated critical habitat are evaluated in accordance with the methods described in the
Agency's Overview Document (U.S. EPA 2004). Screening level methods include use of
standard models such as PRZM-EXAMS, T-REX, and AgDRIFT, all of which are described at
length in the Agency's Overview Document. An additional refinement includes an analysis of
California use reporting data, use of the T-HERPS model to predict daily dietary intake
specifically by the CRLF of esfenvalerate residues in terrestrial invertebrates and small mammal
dietary items, and the probability of individual acute mortality based on dose-response slope
data. Use of such information is consistent with the methodology described in the Agency's
Overview Document, which specifies that "the assessment process may, on a case-by-case basis,
incorporate additional methods, models, and lines of evidence that EPA finds technically
appropriate for risk management objectives" (Section V, page 31 of U.S. EAP 2004).
In accordance with the Overview Document, provisions of the ESA, and the Services'
Endangered Species Consultation Handbook, the assessment of effects associated with
registrations of esfenvalerate is based on an action area. The action area is considered to be the
area directly or indirectly affected by the federal action, as indicated by the exceedance of the
Agency's Levels of Concern (LOCs). It is acknowledged that the action area for a national-level
7
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FIFRA regulatory decision associated with a use of esfenvalerate may potentially involve
numerous areas throughout the United States and its Territories. However, for the purposes of
this assessment, attention will be focused on relevant sections of the action area including those
geographic areas associated with locations of the CRLF and its designated critical habitat within
the state of California.
As part of the "effects determination," one of the following three conclusions will be reached
regarding the potential use of esfenvalerate in accordance with current labels:
• "No effect";
• "May affect, but not likely to adversely affect"; or
• "May affect and likely to adversely affect".
Designated critical habitat identifies specific areas that have the physical and biological features,
(known as primary constituent elements or PCEs) essential to the conservation of the listed
species. The PCEs for CRLFs are aquatic and upland areas where suitable breeding and non-
breeding aquatic habitat is located, interspersed with upland foraging and dispersal habitat
(Section 2.6).
If the results of initial screening-level assessment methods show no direct or indirect effects (no
LOC exceedances) upon individual CRLFs or upon the PCEs of the species' designated critical
habitat, a "no effect" determination is made for use of esfenvalerate as it relates to this species
and its designated critical habitat. If, however, potential direct or indirect effects to individual
CRLFs are anticipated and/or effects may impact the PCEs of the CRLF's designated critical
habitat, a preliminary "may affect" determination is made for the FIFRA regulatory action
regarding esfenvalerate.
If a determination is made that use of esfenvalerate within the action area(s) associated with the
CRLF "may affect" this species or its designated critical habitat, additional information is
considered to refine the potential for exposure and for effects to the CRLF and other taxonomic
groups upon which these species depend (e.g., aquatic and terrestrial vertebrates and
invertebrates, aquatic plants, riparian vegetation, etc.). Additional information, including spatial
analysis (to determine the geographical proximity of CRLF habitat and esfenvalerate use sites)
and further evaluation of the potential impact of esfenvalerate on the PCEs is also used to
determine whether modification of designated critical habitat may occur. Based on the refined
information, the Agency uses the best available information to distinguish those actions that
"may affect, but are not likely to adversely affect" from those actions that "may affect and are
likely to adversely affect" the CRLF or the PCEs of its designated critical habitat. This
information is presented as part of the Risk Characterization in Section 5.0 of this document.
The Agency believes that the analysis of direct and indirect effects to listed species provides the
basis for an analysis of potential effects on the designated critical habitat. Because esfenvalerate
is expected to directly impact living organisms within the action area (defined in Section 2.7),
critical habitat analysis for esfenvalerate is limited in a practical sense to those PCEs of critical
habitat that are biological or that can be reasonably linked to biologically mediated processes
{i.e., the biological resource requirements for the listed species associated with the critical habitat
8
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or important physical aspects of the habitat that may be reasonably influenced through biological
processes). Activities that may modify critical habitat are those that alter the PCEs and
appreciably diminish the value of the habitat. Evaluation of actions related to use of
esfenvalerate that may alter the PCEs of the CRLF's critical habitat form the basis of the critical
habitat impact analysis. Actions that may affect the CRLF's designated critical habitat have
been identified by the Services and are discussed further in Section 2.6.
2.2 Scope
The end result of the EPA pesticide registration process {i.e., the FIFRA regulatory action) is an
approved product label. The label is a legal document that stipulates how and where a given
pesticide may be used. Product labels (also known as end-use labels) describe the formulation
type {e.g., liquid or granular), acceptable methods of application, approved use sites, and any
restrictions on how applications may be conducted. Thus, the use or potential use of
esfenvalerate in accordance with the approved product labels for California is "the action"
relevant to this ecological risk assessment.
Esfenvalerate is a synthetic pyrethroid that is registered for a variety of outdoor food/feed and
non-food/non-feed uses in California. Uses for which esfenvalerate will be assessed using the
risk quotient approach in this document are listed in Table 2-3 and 2-4. Formulations for the
non-food/non-feed uses that will be assessed here include emulsifiable concentrate,
microencapsulated, pressurized liquid, ready-to-use liquid, and wettable powder formulations.
Products registered on food/feed uses that are included in this assessment include emulsifiable
concentrate and ready-to-use liquid formulations. Application types for non-agricultural uses
vary, including band spray, general surface spray, perimeter treatment, spot/crack/crevice
treatment, fog, mount treatment, burrow treatment and others using a variety of equipment.
Applications made in agricultural uses (including Christmas trees and nursery and forestry trees),
include sprays made by aircraft, ground sprayer, hose-end sprayer, and sprinkler irrigation.
Esfenvalerate is also registered for many indoor food/feed and non-food/non-feed uses. Most of
these are applied in spot and crack/crevice treatments, although some are also applied with a
fogger. These uses are expected to be contained within the indoor environments intended for
their use, and are not expected to result in exposure outside of the structure in which they are
applied. Therefore, these uses, which are listed in Table 2-5, will be considered to result in
"no effect" to the CRLF and its designated critical habitat because the exposure pathways
are considered incomplete.
The uses considered in this risk assessment represent currently registered uses according to a
review of all current labels. No other uses are relevant to this assessment. Any other reported
use, such as may be seen in the CDPR Pesticide Use Reporting (PUR) database, represent either
historic uses that have been canceled, mis-reported uses, or mis-use. Historical uses, mis-
reported uses, and misuse are not considered part of the federal action and, therefore, are not
considered in this assessment.
Although current registrations of esfenvalerate allow for use nationwide, this ecological risk
assessment and effects determination addresses currently registered uses of esfenvalerate in
portions of the action area that are reasonably assumed to be biologically relevant to the CRLF
9
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and its designated critical habitat. Further discussion of the action area for the CRLF and its
critical habitat is provided in Section 2.7.
Transformation products and desradates
Estimated exposures are for all isomers (SS, SR, RS, and RR) of cyano-3-phenoxybenzyl-2-(4-
chlorophyl)-3-methylbutyrate. Esfenvalerate is comprised of 75-90% of the SS-isomer but under
aqueous conditions it will also further transform into other isomers (Adelsbach et al. 2003;
Solomon et al. 2001; ATSDR 1993). Degradates identified in environmental fate studies result
from breakdown of the ester linkage (Figure 2-2) and are not of toxicological concern, relative to
esfenvalerate, at the low level of exposures expected (Holmstead et al. 1978; Kelley 2007).
Mixtures
The Agency does not routinely include, in its risk assessments, an evaluation of mixtures of
active ingredients, either those mixtures of multiple active ingredients in product formulations or
those in the applicator's tank. In the case of the product formulations of active ingredients (that
is, a registered product containing more than one active ingredient), each active ingredient is
subject to an individual risk assessment for regulatory decision regarding the active ingredient on
a particular use site. If effects data are available for a formulated product containing more than
one active ingredient, they may be used qualitatively or quantitatively in accordance with the
Agency's Overview Document and the Services' Evaluation Memorandum (U.S., EPA 2004;
USFWS/NMFS 2004).
Esfenvalerate has registered products that contain multiple active ingredients. Analysis of the
available open literature and acute oral mammalian LD50 data for multiple active ingredient
products relative to the single active ingredient is provided in APPENDIX A. The results of this
analysis show that an assessment based on the toxicity of the single active ingredient of
esfenvalerate is appropriate, as no discernable trends in potency that would suggest synergistic
{i.e., more than additive) or antagonistic {i.e., less than additive) interactions were observed.
2.3 Previous Assessments
No assessment for a reregi strati on eligibility decision (RED) has been performed for
esfenvalerate. Previous assessments for this chemical consist mainly of Section 24c Special
Local Needs registrations and new use registrations. Data presented in these assessments were
incorporated in this effects determination.
2.4 Stressor Source and Distribution
2.4.1 Environmental Fate Properties
The substance assessed is cyano-3-phenoxybenzyl-2-(4-chlorophyl)-3-methylbutyrate. It has
two chiral centers, one at the 2C position of the acid and one at the alpha C position of the
alcohol (see Figure 2-la), resulting in four possible isomers: RS, SR, SS, and RR. Fenvalerate is
made up of approximately equal amounts of each isomer, while esfenvalerate is enriched with
the SS-isomer (75 - 90%) (Adelsbach et al. 2003; Solomon et al. 2001; ATSDR 1993). The SS-
10
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alcohol (see Figure 2-la), resulting in four possible isomers: RS, SR, SS, and RR. Fenvalerate is
made up of approximately equal amounts of each isomer, while esfenvalerate is enriched with
the SS-isomer (75 - 90%) (Adelsbach et al. 2003; Solomon et al. 2001; ATSDR 1993). The SS-
isomer is a more effective insecticide than the other isomers (Solomon 2001; Katagi 1993).
Sumitomo Chemical Company, Limited and Bayer Environmental Science canceled all products
registered with fenvalerate as the active ingredient and esfenvalerate has replaced fenvalerate in
most products (Kelley 2007).12 Unless otherwise specified, all fate studies discussed were
conducted using the SS-isomer.
Figure 2-1 provides the chemical structure of esfenvalerate and related compounds and Table 2-1
lists the physico-chemical properties.
Figure 2-1. Chemical Structures of Esfenvalerate and Related Compounds
a. Cyano-3-phenoxybenzyl-2-(4-chlorophyl)-3-methylbutyrate with chiral centers denoted with
(*) at the 2C position of the acid and at the alpha C position of the alcohol (Eisler 1992).1
b. (S^)-alpha-cyano-3-phenoxybenzyl f5^)-2-(4-chlorophenyl)-3-methylbutyrate (esfenvalerate)
c. 4-chloro-alpha-(l-methylethyl)-benzeneacetic acid (CPIA)
1 Federal Register / Vol. 69, No. 150 / Thursday, August 5, 2004 / Notices / 47437 - 47439.
2 Thirty-one products are still listed as active under the PC code for fenvalerate on the NPIRS database
(http://ppis.ceris.purdue.edu/npublic.htm). For many of these products, the label lists the active ingredient as the SS-
isomer (for examples see EPA Registration No. 498-186, 1021-1627, 11623-44). Other products do list fenvalerate
as the active ingredient (for examples see EPA Registration No. 7056-169, 10806-61, 10806-73, 10806-87, 10806-
93).
11
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Property
Value (Method)
MRID #, Author1
Study Status, Date of
Memorandum
0.002 mg/L
Commission 2005
Open Lit., Kelley 2007
Screened
Log K0w
>6 (OECD 117)
5.62 - >6
6.24 at 25°C
467253-04, Comb 2002
Open Lit., Laskowski
2002
Open Lit., European
Commission 2005
Acceptable, 6/1/06
Screened
Screened
1 Open literature (lit.) indicates the study was obtained from the open literature and the study was not submitted to
the EPA for review.
2 Memorandum reviewing the product chemistry sent by Indira Gairola to George Larocca on June 1, 2006 indicated
that the relative density was slightly lower (1.13) than that reported by Comb 2002.
Water and Sediment
The water solubility of esfenvalerate is low at 0.002 - <0.01 mg/L and it is hydrophobic (reported
log Kows range from 5.62 to greater than 6.24) (Laskowski 2002; European Commission 2005;
Comb 2002, MRID 467253-03). It is likely to sorb onto organic matter or suspended particles in
the water column and in sediments (log KocS range from 4.93 to 5.8 mL/g) (Ohm 2001, MRID
45555102). In water, esfenvalerate sterioisomerizes into the RS and SR-isomers (Lee 1989,
MRID 40999303; European Commission 2005). Hydrolysis rates in water are minimal and some
photolysis may occur in shallow water where light is available (Stevenson 1987, MRID
40443801; Lee 1989, MR TP 40999303).2 The photolysis half-life was 6 days for the SS-isomer
and 9 days for all isomers (Stevenson 1987, MRID 40443801).3 Studies on microbial
degradation of esfenvalerate in water and sediment were not submitted to the EPA for review.
However, major degradates of esfenvalerate in water include carbon dioxide, 4-chloro-alpha-(l-
methylethyl)benzeneacetic acid (CPIA), 2-(3-phenoxyphenyl)-3-(4-chlorophenyl)-4-
methylpentane-nitrile (decarboxy-fenvalerate), and 3-phenoxybenzoic acid (Stevenson 1987,
MRID 40443801; Lee 1989, MRID 40999303; European Commission 2005). No minor
degradates were identified. As esfenvalerate has high sorption coefficients, it is not expected to
remain in the water column, but most of it will sorb to organic materials or sediment. Samsoe-
Petersen et al. (2001) measured degradation rates of [chlorophenyl-14C]esfenvalerate and
[phenoxyphenyl-14C]esfenvalerate in pond sediment and 50 percent mineralization occurred
between 73 and 350 days based on 14C02 evolution (Samsoe-Peterson et al. 2001). This
indicates that esfenvalerate sorbed onto sediment is likely to persist. Stereoisomers were not
accounted for in the study. However, the half-lives were based on measured 14C02 and it can be
2 All isomers are stable to hydrolysis (Eisler 1992).
3 The European Commission (2005) reported photolysis half-lives in water of 6 and 10 days and Laskowski (2002)
reported a photolysis half-life in water of 17.2 days. Reviewed data indicate that 47 percent of the SS isomer is still
present after seven days and 13 % is present in the SR and RS isomers (Dynamac Corp. 1988). Small amounts of 4-
chloro-alpha-(l-methylethyl)-benzeneacetic acid (CPIA; up to 27.2 %) and 4-chloro-beta-(l-methylethyl)-alpha -(3-
phenoxyphenyl)-benzenepropane-nitrile (decarboxy-fenvalerate; up to 12.4 percent) also formed (Dynamac Corp.
1988). The half-life for the sum of all isomers was calculated using data from Stevenson (1987) for this document.
The analytical method used in the study could differentiate between the SR + RS and SS + RR isomers; it could not
measure the individual isomers (Stevenson 1987; MRID 40443801).
13
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assumed that conversion of the SS-isomer to other isomers was not considered mineralization or
degradation (Samsoe-Peterson etal. 2001).
A field study examined the distribution of concentrations of esfenvalerate after application
directly to a pond. Samsoe-Petersen et al. (2001) sprayed esfenvalerate directly onto a pond (25
g active ingredient (ai)/hectare, 0.022 lb ai/acre, near the highest recommended field dose in
Denmark) and measured concentrations in the surface microlayer4, water column5, and sediment
fractions6. Two weeks after application, the highest concentrations were found in sediment (9
Hg/kg), with lower concentrations found on the surface microlayer (0.4 |_ig/L) and in the water
column (0.05 |_ig/L) (Samsoe-Petersen etal. 2001). Percentages of the total amount applied in
each compartment were not provided.
Soil
Overall data indicate that esfenvalerate is likely to bind to organic matter in soils and will
degrade on the order of months to years via microbial degradation. When light does reach
esfenvalerate in soil, photolysis can be an important degradation mechanism, especially when
esfenvalerate is not bound to organic materials in soil (Katagi 1991; Katagi 1993). A field soil
dissipation study measured a half-life of 7 to 14 days after a single surface application (0.5
lb/acre) to sandy loam to sandy clay loam soil from Madera, CA (Castle et al. 1990, MRID
41728502).7 The European Commission (2005) estimated field dissipation half-lives of 62-126
days for a summer application and 68 - 87 days from an autumn application of esfenvalerate to
bare sandy silt loam soil.
The main mechanisms of degradation in soil include anaerobic and aerobic degradation (Lee et
al. 1985, MRID 00146578; Gaddamidi etal. 1992, MRID 42396801). Lee etal. (1985, MRID
00146578) measured an aerobic degradation half-life of 75 days in a silt loam soil and
Gaddamidi etal. (1992, MRID 42396801) measured an anaerobic degradation half-life of 77
days in a Hanford loam soil.8 The major degradation product was carbon dioxide and minor9
degradation products included 4"-chloro-(2"'-isopropyl)phenylaceto-2-(3'-
hydroxyphenoxy)phenylacetonitrile, alpha-carbamoyl-3-phenoxybenzyl 2-(4-chlorophenyl)-3-
methylbutyrate 3-phenoxybenzoic acid, and 4-(hydroxyphenoxy)benzoic acid (Dynamac Corp.
1986; Gaddamidi et al. 1992, MRID 42396801). The soil aerobic and anaerobic degradation
half-lives are much higher than the field dissipation half-life measured by Castle et al. (1990,
4 The surface microlayer was sampled using a Garrett screen and the amount sampled corresponded to a thickness of
0.34 mm of water on the surface of the pond (Samsoe-Petersen et al. 2001).
5 Water samples were collected at depths of 10 and 30 cm below the surface and 30 cm above the bottom (Samsoe-
Petersen etal. 2001).
6 Sediments samples were collected from the top 2 cm of the sediment column (Samsoe-Petersen et al. 2001).
7 The plot was irrigated for 3-8 hours six times during the sampling period.
8 Gaddamidi et al. (1992, MRID No. 423968-01) reported concentrations of 14C02, esfenvalerate, and bound
residues. The material balance ranged from 90.9 - 100.3 % of total radioactivity and on day 60 up to 18.3 % of the
total radioactivity was inbound residues, 49.7% was 14C02, and 27.9% was reported as esfenvalerate. No data was
reported for other degradates or for other isomers as 14C02 was reported as the only major degradate. Not enough
information was available to determine whether the results were specific to the SS isomer or to total isomers. As
data was reported for esfenvalerate, the data is assumed to be specific to the SS-isomer.
9 Minor degradates made up less than five percent of the amount applied.
14
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MRID 41728501) (7-14 days) and in the same range as those reported by the European
Commission 2005 (62-126 days). Field dissipation studies measure degradation in the field and
allow for many types of degradation while anaerobic and aerobic degradation are specific to one
type of degradation. Many variables could contribute to the different rates measured; however,
we speculate that sunlight and irrigation contributed to the high rate of degradation in the Castle
et al. (1990, MRID 41728502) study. It is also possible that esfenvalerate sorbed onto soil and
organic particles and remained resistant to analytical extraction methods used.
The open literature also reported data on aerobic and anaerobic metabolism. Laskowski (2002)
reported that aerobic soil half-lives ranged from 15 to 546 days with an average of 107 days and
Kelley (2007) reported anaerobic soil half-lives ranged from 104 to 203 days with an average of
154 days (see APPENDIX J).
As illustrated in Figure 2-2, the photodegradation of esfenvalerate can involve the breakdown of
the ester linkage (Katagi 1991, 1993). Hydration of the cyano group and ether cleavage in the
alcohol moiety can also be enhanced with sunlight (Katagi 1991). Minimal photolysis occurred
in a sandy loam soil, possibly due to binding of esfenvalerate to materials in the sandy loam soil
(Castle 1990, MRID 41728502). However, other research shows that esfenvalerate may undergo
photolysis in some soil types. Laskowski (2002) reported photolysis half-lives in soil of 14.4 to
17.2 days in dry soils of unspecified type and Katagi (1991, 1993) reported photolysis half-lives
in soil ranging from < 1 day in kaolinite and montmorillonite to 100 days in a Noichi upland soil.
Graebing (2004) reported a photolysis half-life in sandy loam soil of 30 days. Primary
photolysis degradation products included carbon dioxide, 2-(3-phenoxyphenyl)-3-(4-
chlorophenyl)-4-methylpentanenitrile, 3-phenoxybenzyl alcohol, 3-phenoxybenzoic acid, and
alpha-carbamoyl-3-phenoxybenzyl 2-(4-chlorophenyl)-3-methylbutyrate (Katagi 1991; Katagi
1993; Castle etal. 1990, MRID 41728501).
15
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d. 4-chloro-beta-(l-methylethyl)-alpha -(3-phenoxyphenyl)-benzenepropane-nitrile
(decarboxyfenvalerate)3
ci
a
11
1 Structure obtained from Chemfinder available at http://chemfinder.cambridgesoft.com/ (accessed 1/11/2008)
2 Structure obtained from IPCSINTOX Databank from the UK National Poisons Information Service Monograph
for esfenvalerate available at http://www.intox.org/databank/documents/chemical/esfenval/ukpid63.htm (accessed
1/11/2008).
3 Structure obtained from Toxnet available at http://toxnet.nlm.nih.gov/index.html (accessed 1/14/2008).
Air
Esfenvalerate has a vapor pressure of approximately 0.063 mPa and an estimated Henry's Law
constant of greater than 1.87 Pa-m3/mol, indicating it is not likely to volatize at environmental
temperatures (Comb 2002, MRID 467253-04). The European Commission (2005) reported a
photochemical oxidative degradation half-life of 1.2 days based on the Atkinson method and
Comb (2002, MRID 467253-04) estimated a half-life of 5.8 hours using the Simplified
Molecular Input Line Entry System (SMILES), indicating that esfenvalerate is not persistent in
air. Based on the short half-life, it is not expected to undergo long range transport. As these
photolysis rates are both estimates, the degradates were not measured or identified. Major and
minor degradates are expected to be similar to those discussed for photolysis in other media.
Table 2-1. Summary of Physico-Chemical Properties of Esfenvalerate.
Property
Value (Method)
MRID #, Author1
Study Status, Date of
Memorandum
Empirical Formula
C25H22C1N03
Molecular Weight
419.9 g/mol
Melting Point
59.5-61.5 °C (OECD 102)
467253-05, Comb 2002
Acceptable, 6/1/06
Boiling Point
Not determinable (OECD 103)
467253-03, Comb 2002
Acceptable, 6/1/06
Relative Density
1.13 g/cm3 at 23°C(OECD 109)2
467253-03, Comb 2002
Acceptable, 6/1/06
Vapor Pressure
6.3 x 10"5 Pa at 25°C (OECD 109)
467253-04, Comb 2002
Acceptable, 6/1/06
6.7 x 10-5 Pa
Open Lit., Jones 2002,
Laskowski 2002
Screened
Henry's Law
Constant
>1.87 Pa-m3/mol at 25°C
(estimated)
467253-04, Comb 2002
Not Reviewed
1.4 x 10"7 Pa-m3/mol
Open Lit., Laskowski
2002
Screened
Water Solubility
< 0.01 mg/L at 20°C (OECD 105)
467253-03, Comb 2002
Acceptable, 6/1/06
0.006 mg/L
Open Lit., Laskowski
2002, European
Screened
12
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Esfenvalerate
Figure 2-2. Proposed Photodegradation Pathway of Esfenvalerate on Soil, Clay Mineral,
and Humic Acid Surfaces based on Katagi 1991 and 1994.1,2
1 This figure was copied from Kelley 2007 with degradates (II) and (VII) corrected based on Katagi 1991.
2 Below is a list of degradation products of esfenvalerate shown in Figure 2-2. Major degradates are denoted by an
asterisk (*) after the name.
2-(3-phenoxyphenyl)-3-(4-chlorophenyl)-4-methylpentanenitrile (II)*
alpha-carbamoyl-3-phenoxybenzyl 2-(4-chlorophenyl)-3-methylbutyrate (III)*
3-phenoxybenzyl cyanide (IV)
3-phenoxyphenylacetic acid (V)
alpha-cyano-3 -(4-hydroxyphenoxy)benzyl 2-(4-chlorophenyl)-3 -methylbutyrate (VI)
alpha-cyano-3 -hydroxybenzyl 2-(4-chlorophenyl)-3 -methylbutyrate (VII)
alpha-cyano-3-cyanobenzyl 2-(4-chlorophenyl)-3-methylbutyrate (VIII)
3-phenoxybenaldehyde (IX)
3-phenoxybenzoic acid (X)*
Groundwater
Based on a leaching study and high Kows, KdS, and Koms, esfenvalerate is unlikely to leach into
ground water (Merritt 1992, MRID 42350201; Ohm 2001, MRID 45555102; Houston 1978).
16
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Bioaccumulation
Carp (Cyprinus carpio) were exposed to 0.046 - 0.061 parts per billion 14C-esfenvalerate labeled
at the phenoxyphenyl group or 14C-esfenvalerate labeled at the chlorophenyl group for 28 days
followed by a 14 day depuration phase. Total radioactivity, SS-isomer, SR-isomer, and
metabolites were measured in carp. Daily bioconcentration factors (BCF) for total isomer
residues ranged from 334-3650 (Oshima et al. 1991, MRID 42922401; Oshima et al. 1993,
MRID 42922401).10 Approximately 70% of accumulated radioactivity and residues were
eliminated during the 14-day depuration period, resulting in an estimated half-life of 7-8 days.
This indicates that after exposure to the esfenvalerate stops, approximately half of the
esfenvalerate and its metabolites in the carp will be removed from the fish in 7 to 8 days. The
metabolic pathways were oxidation of the 4' position of the alcohol moiety and the 3 position of
the acid moiety, cleavage of the ester linkage, and conjugation of the resultant phenol and acid
with glucuronic acid or sulfuric acid (Oshima et al. 1993, MRID 42922401). The major
metabolites were the glucuronide of 4'-OH-fenvalerate (contributing to up to 6-34% of 14C in
fish), 4'-OH-fenvalerate (contributing to up to 1-5% of 14C in fish), sulfate of 4'-OH-PB acid
(contributing to up to 2-6% of 14C in fish), and CPIA (contributing to up to 6-15% of 14C in fish)
(Oshima et al. 1991, MRID 42170501).
When metabolism, growth dilution, and other confounding factors are ignored, bioconcentration
factors are expected to increase with increasing log K0ws (for log K0w up to ~ 6) (Gobas el al.
2000; Bintein et al. 1993). Using the relationship published by Mackay between K0w and BCF,
results in a predicted BCF of 48000 or log BCF of 4.68 for esfenvalerate (Gobas et al. 2000).11
This indicates that esfenvalerate has a high potential to bioconcentrate in organisms. However,
measured BCFs for carp are much lower than predicted and significant bioconcentration is not
expected to occur in organisms that readily metabolize pyrethroids such as mammals and birds.
Mammals and birds tend to metabolize pyrethroids while insects are more susceptible to toxicity
and bioconcentration because of less developed metabolic systems (Eisler 1992). The ability of
fish to metabolize pyrethroids varies. For example, carp are known to have a well developed
esterase metabolism that will metabolize esfenvalerate, thus reducing its bioconcentration and
toxicity (Adelsbach et al. 2003). On the other hand, rainbow trout are known to have decreased
rates of metabolism and low rates of esterase activity for pyrethroids; they are more susceptible
to toxicity and bioconcentration of esfenvalerate (Adelsbach et al. 2003). Amphibians in later
developmental stages may have a more developed metabolic system than their younger
counterparts and amphibians in developmental stages can be more susceptible to xenobiotic
toxicity (Greulich et al. 2003).
10 The registrant submitted results comparing bioconcentration of d-trans-Phenothrin in carp and bluegill. The study
showed similar bioconcentration and metabolism and a study on esfenvalerate with carp was accepted to fulfill the
bioaccumulation study requirements (Review memo dated 11/29/1994).
11 The BCF was estimated using the equation BCF = 0.048 Kow and a log Kow of 6. This value was estimated to
qualitatively show the bioconcentration potential of esfenvalerate (Gobas et al. 2000). It should be used with
caution for other purposes as the log Kow approaches the limit of the relationship and significant metabolism is
expected in many organisms (Gobas et al. 2000; Eisler 1992).
17
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Degradates
The major pathway of degradation in soils and sediments is expected to be aerobic or anaerobic
metabolism. The only major aerobic and anaerobic degradate was carbon dioxide (Gaddamidi et
al. 1992, MRID 42396801; Lee etal. 1985, MR TP 00146578). When sunlight is available,
photolysis may occur and photolysis degradates include up to 27.2 % CPIA and 12.4 %
decarboxy-fenvalerate (Dynamac 1988). Based on the data available, decarboxy fenvalerate is
less toxic (rat oral LD50 was 67-87 mg/kg for esfenvalerate and >500 mg/kg for
decarboxyfenvalerate) and concentrations of decarboxyfenvalerate will be much lower,
approximately 87% lower, than the parent compound (Kelley 2007; Holmstead etal. 1987). No
toxicity data were available for CPIA; however, breaking the ester bond is expected to
significantly decrease the toxicity of the substance as compared to the parent compound. As the
expected toxicity and exposure of the degradates do not exceed that of esfenvalerate, they were
not considered to contribute substantially to the toxicity exposure. The SS-isomer may
sterioisomerize into the RS and SR-isomers in water. However, application rates are based on
the SS-isomer and half-lives used in the exposure estimates are based on breakdown of the
combined isomers. Thus, in the aquatic environment, the estimated concentration of the SS-
isomer represents the sum of all isomers present or the maximum concentration of the SS-
isomer. As the SS-isomer is the most toxic isomer for insects and only limited toxicity data is
available for other individual isomers, this may be assumed to be the most protective assumption
(ATSDR 2003; Adelsbach et al. 2003; Eisler 1992).12
Summary of Environmental Fate Properties
Table 2-2 lists the environmental fate properties of esfenvalerate, along with the major and minor
degradates detected in the submitted environmental fate and transport studies.
Table 2-2. Summary of Esfenvalerate Environmental Fate Properties.
Study
Value, SS-isomer/All
Isomers1 (units)
Major Degradates
Minor Degradates
MRID#,
Author2
Study Status
(Date of
Memorandum
Referenced)
Hydrolysis
Minimal degradation in
30 days at pH 5, 7, 9,
All isomers
Not Applicable
40999303, Lee
1989
Acceptable
(3/14/1991)
Direct
Aqueous
Photolysis
T12 = 6 days at pH 5,
SS-isomer
T1/2= 9 days, All
isomers
C02, CPIA, decarboxyfenvalerate
40443801,
Stevenson 1987
40443801,
Stevenson 1987
Acceptable
(1/5/1988
,7/27/1992)
Calculated for
this review
Soil
Photolysis
Minimal in 30 days,
SS-isomer3
C02, CPIA, decarboxy-
fenvalerate
41728501
Castle et al.
Acceptable
(3/6/1991)
12 When the SS-isomer is used in aquatic toxicology studies it will also undergo isomerization when placed in water.
The only way to ensure exposure to one isomer to be able to compare the toxicity of the different isomers to aquatic
organisms would be to inject the organism.
18
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Study
Value, SS-isomer/All
Isomers1 (units)
Major Degradates
Minor Degradates
MRID #,
Author2
Study Status
(Date of
Memorandum
Referenced)
Range from < 1 day in
kaolinite to 100 days in
a Noichi upland soil,
SS-isomer
3-phenoxybenzyl alcohol, 3-
phenoxybenzoic acid, and
decarboxy fenvalerate
1990
Open Lit.,
Katagi 1991,
Katagi 1993
Screened
Aerobic Soil
Metabolism
T1/2= 75 days in silt
loam soil, SS-isomer3
C02, 4' '-chloro-(2''
isopropyl)phenylaceto-2-(3
hydroxyphenoxy)phenylacetonitril
e, alpha-carbamoyl-3-
phenoxybenzyl 2-(4-chlorophenyl)-
3-methylbutyrate 3-
phenoxybenzoic acid, and 4-
(hydroxyphenoxy)benzoic acid
00146578,
Lee etal. 1985
Acceptable
(11/29/1994)
Reported range of 15 -
546 days in literature
with an average of 107
days
Open Lit.,
Laskowski
2002
Screened
Anaerobic
Soil
Metabolism
T1/2 = 77 days in sandy
loam, SS-isomer3
C02> 4' '-Chloro-(2''
isopropyl)phenylaceto-2-(3
hydroxyphenoxy)phenylacetonitril
e, 4"-chloro-(2 "
isopropyl)phenylaceto-2-(3
phenoxy)phenylacetamide, 3-
phenoxybenzoic acid, and 4-
(hydroxyphenoxy)benzoic acid
42396801
Gaddamidi et
al. 1992
Acceptable
(3/30/1993)
Reported range of 104 -
203 days with an
average of 154 days
Open Lit.,
Kelley 2007
Screened
Anaerobic
Aquatic
Metabolism
Not available
Not available
Aerobic
Aquatic
Metabolism
Not available
Not available
19
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Study
Value, SS-isomer/All
Isomers1 (units)
Major Degradates
Minor Degradates
MRID #,
Author2
Study Status
(Date of
Memorandum
Referenced)
Kd-ads / Kd-des
(mL/g)
600, 700, 750, 1,700,
5,200, 15,500 (sandy
loam, sandy clay loam,
silt loam, loam, loamy
sand, silt clay loam)
Not applicable
45555102
Ohm 2001
Not Reviewed
I"Voc- ads / Koc-
des (mL/g)
85,700, 140,000,
141,700, 171,700,
375,000, 596,200
(sandy loam, sandy
clay loam, loam,
loamy sand, silt loam,
silt clay loam)
Not applicable
K0M(mL/g)
50,000, 77,800, 85,000,
101,000, 187,500,
352,300 (sandy loam,
sandy clay loam, loam,
loamy sand, silt loam,
silt clay loam)
Not applicable
Terrestrial
Field
Dissipation
11^)
T =14 days in sandy
loam/sandy clay loam,
Isomer information was
not specified
Not reported
41728502
Castle et al.
1990 and
supplement
Acceptable
(7/27/1992)
Aquatic
Field
Dissipation
Not available
Not available
Bioconcentr
ation Factor
334-3650 Carp, All
isomers
Metabolites included glucuronide
of 4'-OH-fenvalerate, CPIA, 4
OH-fenvalerate, and sulfate of 4
OH-PB acid
42922401
Oshima et al.
1993
42170501
Oshima et al.
1991
Acceptable
(11/29/1994)
1 Cyano-3-phenoxybenzyl-2-(4-chlorophyl)-3-methylbutyrate has four different isomers. All fate studies were
conducted using the SS-isomer but the rate data may apply to the SS-isomer or total isomers as the SS-isomer may
undergo isomerization. If the SS-isomer is listed the data was specific to the SS-isomer. If all isomers is listed, then
the rate data is specific to total isomers.
2 Open literature (lit.) indicates the study was obtained from the open literature and the study was not submitted to
the EPA for review.
3 Limited information was available on the various isomers in the study. However, the value was reported as
specific to esfenvalerate or the SS-isomer.
2.4.2 Environmental Transport Mechanisms
Potential transport mechanisms include pesticide surface water runoff, spray drift, and secondary
drift of volatilized or soil-bound residues leading to deposition onto nearby or more distant
20
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ecosystems. Surface water runoff and spray drift are expected to be the major routes of exposure
for esfenvalerate. Because of its high tendency to sorb to soil (as evidenced by high Kd/K0c
values), esfenvalerate is expected to reach water bodies primarily sorbed to sediment. With its
persistence, esfenvalerate may accumulate in sediment, where it may be a reservoir for exposure
for benthic organisms Esfenvalerate is not persistent in the atmosphere and is not expected to
migrate via long range transport.
In general, deposition of drifting or volatilized pesticides is expected to be greatest close to the
site of application. Computer models of spray drift (AgDRIFT) are used to determine potential
exposures to aquatic and terrestrial organisms via spray drift. Since esfenvalerate is expected to
be used in all areas occupied by the CRLF, use of spray drift modeling was done to examine the
potential for spray drift buffers to mitigate effects by using the estimated fraction spray drift with
the buffer to estimate exposure.
2.4.3 Mechanism of Action
Esfenvalerate is a type two synthetic pyrethroid. The primary mechanism of action of
pyrethroids is interference with the closing of voltage-dependent sodium channels, resulting in
repetitive firing of neurons (ATSDR 2003). After exposure the organism may exhibit
hyperexcitation, tremors, convulsions, and/or salivation, followed by lethargy, paralysis, and
death (Kelley 2007). Type two pyrethroids, those that contain a cyano group in the alcohol and
halogen in the acid, are also reported to have effects at the presynaptic membrane of voltage-
dependent calcium channels and to interfere with ATPase enzymes involved with maintaining
ionic concentration gradients across membranes (Solomon etal. 2001).
2.4.4 Use Characterization
Analysis of labeled use information is the critical first step in evaluating the federal action. The
current label for esfenvalerate represents the FIFRA regulatory action; therefore, labeled use and
application rates specified on the label form the basis of this assessment. The assessment of use
information is critical to the development of the action area and selection of appropriate
modeling scenarios and inputs. APPENDIX H lists the labels where esfenvalerate is an active
ingredient (ai) and that are assessed in this document.
Esfenvalerate is a broad spectrum nonselective insecticide that is used to control a variety of
insects in agriculture, commercial, residential, and industrial settings both indoors and outdoors.
National uses are similar to those registered in California. Three labels13 cover uses for
agricultural crops, including the following general categories of food crops: almonds, filbert,
pecan, walnut, broccoli, Chinese broccoli, cabbage, Chinese cabbage, cauliflower, collards
13 Agricultural labels include Dupont Asana ® XL (EPA Registration Number 352-515, label date April 6, 2006),
Esfenvalerate AG (EPA Registration Number 53883-135, label date September 17, 2004), and EsfenStar 8% EC
(EPA Registration Number 71532-21, label date April 24, 2007). All information on the agricultural uses come
from these three labels. In California, Dupont Asana ® XL may also be referred to as Adjourn Insecticide and is the
only agricultural label listed as registered in California in the National Pesticide Information Retrieval System
(NPIRS) available at http://ppis.ceris.purdue.edu/npublic.htm. However, the other labels do not state not to use the
product in California.
21
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kohlrabi mustard, corn (unspecified), field corn, pop corn, sweet corn, sunflower, apple, apricot,
cherry, nectarine, peach, pear, plum, prune, lettuce, head, cucumber, eggplant, melons,
cantaloupe, honeydew, musk melons, watermelons, pumpkin, squash, summer squash, winter
squash, radish, turnip, white/Irish potato, artichoke, dried type beans, succulent (snap) beans,
carrot, lentils, peas, dried-type peas, pepper, sugar beet, tomato, kiwi, peanuts, sugarcane,
sorghum14, and soybeans15. Agricultural nonfood crop uses include cotton, Christmas tree
plantings, conifer plantations, conifer seed orchards, forest tree nurseries, and non-cropland
(excluding public land such as forests, parks, or recreational areas). Dupont Asana® XL is also
registered for a special local need, e.g., a 24C label, for the control of grasshoppers and crickets
on forest sites in California (EPA Registration Number CA-990022). The agricultural
formulations are all sold as emulsifiable concentrates. In general, all crops may be treated via
chemigation (via an irrigation system), aerial, and ground application methods. Esfenvalerate
may not be applied by ground within 25 feet or by aerial methods within 150 feet of lakes,
reservoirs, rivers, permanent streams, marshes, natural ponds, estuaries, or commercial fish
ponds. The buffer zone must be increased to 450 feet when an ultralow volume (ULV)
application is made. Esfenvalerate may be applied at plant as well for corn and sugarbeet. Table
2-3 specifies the maximum application rates for each agricultural use. Labels did not specify a
maximum number of applications per year; however, this may be inferred from the maximum
single application rate and the maximum seasonal application rates.
Table 2-3. Labeled Agricultural Uses Assessed in this Document.1
Crop
Group
Crop/ Use
Maximum Single
Application Rate (lbs
ai/acre)
Maximum Seasonal Rate
(lbs ai/acre)
Seasons per
Year2
Application
Interval
(days)
Tree Nuts
Almonds
0.1
0.2
l3
NS4
Filbert
0.1
0.2
l5
NS and 7
Pecan
0.075
0.3
l5
7
Walnut
0.1
0.2
l6
7
Cole Crops
Broccoli
0.05
0.4
1 to 2
NS and 7
Broccoli, Chinese
0.05
0.4
1 to 2
NS
Cabbage
0.05
NS
1 to 3
NS
Cabbage, Chinese
0.05
0.4
1 to 3
NS
Cauliflower
0.05
0.4
1 to 2
NS
Collards
0.05
0.2
2 to 3
NS
Kohlrabi
0.05
0.35
2 to 35
NS
Mustard
0.05
0.2
2 to 35
NS
Corn
Corn
0.05
0.5
see below
NS
Corn, field
0.05
0.25
1
NS
Corn, field-at plant
0.0023 lbs ai per 1000
sq ft of row
0.05
1
Corn, pop
0.05
0.5
1
NS
Corn, sweet
0.05
0.5
1 to 2
NS
14 Use on sorghum is restricted in California on two agricultural labels but is not restricted for Esfenvalerate AG.
15 Soybeans are not commonly grown in California and were not assessed in this document.
22
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Crop
Group
Crop/ Use
Maximum Single
Application Rate (lbs
ai/acre)
Maximum Seasonal Rate
(lbs ai/acre)
Seasons per
Year2
Application
Interval
(days)
Sunflower
0.05
0.2
1 to 25
NS
Fruit
Apple
0.075
0.525 lbs
1
7
Apricot
0.075
0.375 / 0.3 between bloom
and harvest
,5
NS
Cherry
0.075
0.375 / 0.3 between bloom
and harvest
,5
NS
Nectarine
0.075
0.375 / 0.3 between bloom
and harvest
1
NS
Peach
0.075
0.375 / 0.3 between bloom
and harvest
1
NS
Pear
0.075 season/0.075
between bloom and
harvest / 0.1 dormant
0.375 season/0.225
between bloom and harvest
/ 0.2 dormant
1
NS
Plum
0.075
0.375 / 0.3 between bloom
and harvest
,7
NS
Prune
0.075
0.375 / 0.3 between bloom
and harvest
,7
NS
Cucumbers,
Squash,
and Melons
Cucumber
0.05
0.25
1
NS
Eggplant
0.05
0.35
1
7-10
Melons
0.05
0.25
1
NS
Melons, cantaloupe
0.05
0.25
1
NS
Melons, honeydew
0.05
0.25
1
NS
Melons, musk
0.05
0.25
,5
NS
Melons, water
0.05
0.25
,5
NS
Pumpkin
0.05
0.25
1
NS
Squash (unspecified)
0.05
0.25
,5
NS
Squash (summer)
0.05
0.25
1
NS
Squash (winter)
0.05
0.25
,5
NS
Potato
Potato, white/Irish
0.05
0.35
1
NS
Turnip
0.05
0.5
,5
NS
Row Crops
Artichoke
0.05
0.15
1 7
7
Beans, dried type
0.05
0.2
1
NS and 7
Beans, succulent
(snap)
0.05
0.2
1
NS and 7
Carrot
0.05
0.5
1
NS
Lentils
0.05
0.2
1
NS
Peas (unspecified)
2.892E-04 lb/gal
NS
1
NS and 7
Peas, dried-type
0.05
0.2
,5
7
Pepper
0.05
0.35
1
7
Sugar beet
Sugar beet
0.05
0.15
1
NS
Sugar beet-at plant
0.0023 lbs ai per 1000
sq ft of row
0.05 at plant, 0.25 at plant
and foliar
1
NS
Crops Not
Cotton (unspecified)
0.05
0.5
1
NS
23
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Crop
Group
Crop/ Use
Maximum Single
Application Rate (lbs
ai/acre)
Maximum Seasonal Rate
(lbs ai/acre)
Seasons per
Year2
Application
Interval
(days)
in Groups
Kiwi
0.05
0.35
l7
7
Lettuce, head
0.05
0.35
1-2
NS
Peanuts
0.05
0.15
NS
Radish
0.05
0.1
3-5
NS
Sugarcane
0.05
0.2
NS
Sorghum
0.05
0.15
1 crop for
grain, hay
several times
per year
NS
Tomato
0.05
0.5
1
NS
Forest Tree
Nursery
and Tree
Nursery
Christmas tree
plantings, Conifer
plantations seed
orchards, Forest tree
nurseries
0.05
1.6
1
NS, 7 for 2
sprays or
every 28
Non-
cropland
Prevent pests from
getting to cropland
0.05
0.5
NS
NS
1 Unless at plant application is specified in the Crop/Use column, esfenvalerate may be applied using aerial ,
ground, and chemigation methods
2 Seasons per year were obtained from Memorandum from Monisha Kaul in BEAD to Melissa Panger in
EFED dated 2/28/2007, unless stated otherwise.
3 Mosz, N. Almond Timeline, 2002. Online: http://pestdata.ncsu.edu/croptimelines/pdf/CAalmond.pdf
4 NS stands for not specified
5 Seasons per year were assumed from similar crops in the crop grouping.
6 Mosz, N. Walnut Timeline, 2002. Online: http://pestdata.ncsu.edu/croptimelines/pdf/CAwalnut.pdf
7 USDA crop profiles, available online at http://cipm.ncsu.edu/cropprofiles/cropprofiles.cfm (accessed on
December 1, 2007).
There are approximately 132 non-agricultural products registered nationally16 and 81 products in
registered in California17. Non-agricultural labels allow for use in commercial, industrial, and
residential settings, including homes, office buildings, restaurants, schools, motels, barns,
industrial buildings, poultry housing, feedlots, railroad cars, lawns, apartment buildings,
warehouses, theatres, pet housing, kennels, dairy barns, truck trailers, milk rooms, livestock
housing, garbage bins and receptacles, athletic facilities, trees, vehicles, boats, campers,
ornamental trees and landscapes, along subterranean cables, poles, and post holes, alleys, general
outdoor areas, and general indoor areas. Non-agricultural products may also be used in the home
and garden and may be used on food crops such as fruits, tree nuts, vegetables, beans, melons,
and nonfood crops such as ornamentals, shrubs, roses, shade trees, etc. Residential uses allow
for use on blueberries and caneberries (blackberries, boysenberries, dewberries, loganberries,
raspberries, youngberries, and varieties of these) while these uses are prohibited in California on
16 Based on Office of Pesticides Information Network (OPPIN) search of pending and active registrations searched
on November 14, 2007.
17 Label numbers based on NPIRS state search by active ingredient on November 14, 2007. Some EPA registration
numbers have more than one trade name and are listed multiple times on the list of products.
24
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agricultural crops. Indoor uses include as a crack and crevice treatment, spot treatments, surface
spray, foggers to treat insects such as ants, crickets, cockroaches, ticks, and various other insects.
Outdoor uses include uses such as building perimeter, swarming termites, wood destroying pests,
lawns, general outdoor surfaces, turf grass, automobiles, ant mounds, hornet and wasp nests, and
mosquito breeding areas. Mosquito breeding areas are defined by the labels as sites where
mosquitoes rest, harbor, or breed such as in tall grass, shrubbery, backyards, lawns, and around
windows and doors (EPA Registration No. 1021-1815 and 1021-1794). Formulations are sold as
emulsifiable concentrates, wettable powders, microencapsulation, ready-to-use liquids, and
pressurized liquids. Application methods include spray, pressurized spray, hose-end spray,
power sprayer, aerosol spray, tank top sprayer, compressed air sprayer, and fogger. Maximum
single application rates for non-agricultural uses are provided in Table 2-4. Most of these labels
did not give a maximum amount of esfenvalerate to apply per season or year. They usually
supplied a maximum amount applied per specified area. Indoor uses listed in Table 2-5 were
assumed to have incomplete exposure pathways to the CRLF and its designated critical habitat.
Table 2-4. Labeled Non-agricultural Uses Assessed in this Document.1'2
Use Group
Specific Uses
Maximum
Single
Application
Rate (lbs ai /
acre)
Maximum
Seasonal Rate
(lbs ai / acre)
Application
Methods
Application
Interval
(days)
Forests
Forest Trees (all or
unspecified), Softwoods,
Conifers
0.05
1.6
ground,
aerial
As needed
Residential,
Commercial, and
Industrial Areas:
Agricultural/farm
structures/buildings
and equipment,
Commercial
Storage/warehouse
premises, Non-
agricultural Outdoor
Buildings/structures,
Non-agricultural
Uncultivated
Areas/soils,
Recreation Areas
General Outdoor
Surfaces: Unspecified,
Paths and Patios,
Refuse/Solid Waste Sites
0.51
NS
spray
NS
Building Perimeter
0.2
NS
spray,
microencaps
ulation
NS and 7
Home and Garden:
Ornamental Trees and
Plants, Herbaceous Plants,
Nonflowering Plants,
Woody Shrubs and Vines,
Fruits, Nuts, Berries and
Vegetables, Shade Trees
NS
NS
spray
NS and 7 to
14
Lawn and Grass
0.2
NS
spray,
microencaps
ulation
NS
Outside of Automobiles,
Vehicles, Taxis,
Limousines, Truck
Trailers, Railroad Cars,
Tires
NS
NS
spray,
fogger
NS
Kennels and Animal
Housing Areas
0.1
NS
spray,
fogger
NS
25
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Use Group
Specific Uses
Maximum
Single
Application
Rate (lbs ai /
acre)
Maximum
Seasonal Rate
(lbs ai / acre)
Application
Methods
Application
Interval
(days)
Ant Mounds and Wasp
and Hornet Nests
NS
NS
spray,
fogger,
microencaps
ulation
NS
Mosquito breeding areas
0.2
NS
spray,
microencaps
ulation
NS
1 The Labeling and Use Information (LUIS) report lists Wide Area/General Outdoor Treatment (Public Health Use).
This listing could easily be mistaken for a general wide area use that may involve significant use near aquatic
environments. The labels referenced for this use includes EPA Registration Numbers 1021-1764, 1021-1635, 1021-
1852, and 1021-1701. The outdoor uses allowed on these labels include treatment of wasp, hornet, yellow jacket
nests, fire ant housing, and to kill fire ants, mud daubers, scorpions, spiders, crickets, carpenter ants, harvester ants,
centipedes, earwigs, and sowbugs. These uses are covered by the general outdoor uses already listed in Table 2-4.
2 NS=Not Specified.
Table 2-5. Labeled Non- agricultural Uses Qualitatively Assessed in this Document
Use Group
Specific Uses
Reason for Exclusion
Interior Vehicle Uses
Vehicles, Boats, Campers,
Railroad Cars, and Truck
Trailers
Minimal chance for exposure in
terrestrial or aquatic
environments
Indoor Uses: Commercial,
Residential, and Industrial
Buildings, Cadavers and
Caskets, Voids in
Equipment and Structures,
Grain Storage Facilities
Surface Spray, Space Spray,
Crack and Crevice Treatment,
and Spot Treatment
Minimal chance for exposure in
terrestrial or aquatic
environments
The Agency's Biological and Economic Analysis Division (BEAD) provides an analysis of both
national- and county-level usage information (Kaul and Jones, 2006) using state-level usage data
obtained from USDA-NASS18, Doane (www.doane.com; the full dataset is not provided due to
its proprietary nature) and the California's Department of Pesticide Regulation Pesticide Use
Reporting (CDPR PUR) database19. CDPR PUR is considered a more comprehensive source of
usage data than USDA-NASS or EPA proprietary databases, and thus the usage data reported for
esfenvalerate by county in this California-specific assessment were generated using CDPR PUR
data. Four years (2002-2005) of usage data were included in this analysis. Data from CDPR
PUR were obtained for every pesticide application made on every use site at the section level
(approximately one square mile) of the public land survey system. BEAD summarized these
data to the county level by site, pesticide, and unit treated. Calculating county-level usage
18 United States Depart of Agriculture (USDA), National Agricultural Statistics Service (NASS) Chemical Use
Reports provide summary pesticide usage statistics for select agricultural use sites by chemical, crop and state. See
http://www.usda.gOv/nass/pubs/estindxl.htm#agchem.
19 The California Department of Pesticide Regulation's Pesticide Use Reporting database provides a census of
pesticide applications in the state. See http://www.cdpr.ca.gov/docs/pur/purmain.htm.
26
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involved summarizing across all applications made within a section and then across all sections
within a county for each use site and for each pesticide. The county level usage data that were
calculated include: average annual pounds applied, average annual area treated, and average and
maximum application rate across all five years. The units of area treated are also provided where
available.
California PUR Usage Data
The state of California requires that all pesticide applications (excluding private homeowner
uses) be reported. This data is collected in the PUR (pesticide use reporting) database. The
Office of Pesticide Programs' (OPP) Biological and Economic Analysis Division (BEAD)
performed an analysis (J. Carter and A. Grube , October 2, 2007) of the PUR data for years 2002
to 2005, including data for esfenvalerate. Use of esfenvalerate was reported in a total of 47
counties over that time. Esfenvalerate is registered for many non-agricultural uses and many
products are manufactured for use by homeowners. This analysis does not include usage by
homeowners because a reliable data source for this information is not available.
Some uses reported in the CDPR PUR database are different than those considered in the
assessment (soil fumigation/preplant, vertebrate control, leek, research commodity, and barley).
The uses considered in this risk assessment represent all currently registered uses according to a
review of all current labels. No other uses are relevant to this assessment. Any other reported
use, such as may be seen in the CDPR PUR database, represent either historic uses that have
been canceled, mis-reported uses, or mis-use. Historical uses, mis-reported uses, and misuse are
not considered part of the federal action and, therefore are not considered in this assessment.
According to the CDPR PUR database, a total of 29,918 lbs of esfenvalerate were used in
California in 2002, 33,495 lbs in 2003, 30,817 lbs in 2004, and 32,566 lbs in 2005. The average
annual number of pounds applied over that four-year period was 31,699. Figure 2-3 below
shows the reported average annual number of pounds used in each county between 2002 and
2005 for those counties with >500 pounds per year. Seventy-seven percent of the average annual
pounds applied were applied in eleven counties: Fresno, Monterey, San Joaquin, Stanislaus,
Imperial, Kern, Sutter, Tulare, Merced, Butte, and Madera counties. Ninety-nine percent of the
usage is accounted for by the counties applying more than 100 average pounds annually
(counties above Contra Costa in APPENDIX I).
27
-------
Average Annual Pounds Applied
0 1,000 2,000 3,000 4,000 5,000
Fresno
Monterey
San Joaquin
Stanislaus
Imperial
Kern
Sutter
Tulare
c
3 Merced
O
° Butte
Madera
Glenn
Santa Barbara
Yuba
Kings
Ventura
Yolo
Riverside
]
]
Figure 2-3. Average Total Pounds Applied in Each County for the Years 2002-2005.
Counties applying on average more than 500 pounds per year were included in the figure.
Based on the average annual pounds applied between 2002 and 2005, greater than 1000 pounds
of esfenvalerate is applied to nine crops annually: almond, peach, tomato, corn, artichoke,
walnut, prune, lettuce, and nectarine. Approximately, 20 percent of esfenvalerate is applied to
almonds, ten percent is applied to peach, tomato, and corn, and seven percent is applied to
artichokes. All other uses accounted for less than five percent of the total esfenvalerate used in
California. A summary of esfenvalerate usage for all California use sites is provided in Table
2-6.
28
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Table 2-6. Summary of California Department of Pesticide Registration (CDPR) Pesticide
Use Reporting (PUR) Data from 2002 to 2005 for Currently Registered Esfenvalerate
Uses.1
Site Name
Average Annual
Pounds Applied2
Average
Application
Rate
Average
95 Percentile
Application
Rate
Average
99 Percentile
Application
Rate
Average
Maximum
Application
Rate
Almond
6778.9
0.05
0.07
0.09
0.20
Peach
3158.3
0.05
0.06
0.07
0.15
Tomato
3130.9
0.04
0.04
0.04
0.04
Corn
3006.0
0.05
0.05
0.06
0.07
Artichoke, Globe
2086.5
0.05
0.06
0.07
0.09
Walnut
1459.5
0.06
0.08
0.09
0.11
Prune
1307.6
0.04
0.06
0.07
0.11
Lettuce, Leaf
1193.0
0.04
0.05
0.05
0.07
Nectarine
1103.0
0.05
0.06
0.08
0.13
Cherry
867.2
0.04
0.06
0.06
0.09
Sugarbeet
860.6
0.04
0.04
0.04
0.08
Plum
805.1
0.04
0.06
0.08
0.13
Broccoli
768.0
0.04
0.04
0.06
0.10
Potato
671.8
0.05
0.09
0.12
0.14
Sunflower
578.9
0.05
0.07
0.07
0.10
Apricot
462.2
0.04
0.05
0.10
0.12
Bean, Dried
460.1
0.04
0.04
0.05
0.05
Carrot
447.5
0.05
0.05
0.08
0.08
Pear
435.0
0.05
0.07
0.14
0.20
Cauliflower
300.0
0.04
0.05
0.05
0.09
Pepper
294.9
0.04
0.06
0.07
0.08
Structural Pest
Control
208.7
NS3
NS
NS
NS
Apple
200.8
0.05
0.10
0.15
0.15
Cotton
172.6
0.04
0.05
0.05
0.05
Cabbage
158.2
0.04
0.05
0.06
0.06
Bean, Succulent
104.5
0.04
0.05
0.07
0.07
Cantaloupe
100.8
0.04
0.05
0.06
0.06
N-Outdoor Trees
92.3
0.04
0.06
0.10
0.10
Bean, Unspecified
50.5
0.04
0.04
0.05
0.05
N-Greenhouse
Flower
48.1
0.01
0.01
0.01
0.01
Peas
44.0
0.04
0.05
0.05
0.05
Watermelon
43.8
0.05
0.06
0.06
0.06
N-Outdoor Plants in
Containers
43.2
0.07
0.10
0.11
0.11
Melon
40.2
0.05
0.10
0.10
0.10
Pumpkin
33.1
0.05
0.05
0.05
0.05
Squash
32.1
0.05
0.06
0.07
0.07
Radish
29.1
0.18
0.18
0.18
0.31
Eggplant
20.8
0.07
0.10
0.11
0.17
Cucumber
20.4
0.05
0.09
0.09
0.09
29
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Site Name
Average Annual
Pounds Applied2
Average
Application
Rate
Average
95 Percentile
Application
Rate
Average
99 Percentile
Application
Rate
Average
Maximum
Application
Rate
Rights of Way
15.1
0.04
0.04
0.04
0.04
Uncultivated - Non
Agricultural
11.0
0.05
0.06
0.06
0.06
Collard
9.4
0.05
0.05
0.07
0.07
Chinese Cabbage
(Nappa)
8.9
0.04
0.05
0.06
0.06
Landscape
Maintenance
5.7
0.04
0.04
0.04
0.04
Pecan
5.7
0.04
0.07
0.07
0.07
Mustard
4.9
0.04
0.05
0.05
0.05
Pistachio
4.2
0.03
0.03
0.03
0.03
GrapeAVine Grape
3.7
0.49
0.49
0.49
0.49
N-Greenhouse Plants
in Containers
1.8
0.09
0.11
0.11
0.11
N-Greenhouse
Transplants
1.8
0.03
0.04
0.13
0.13
Endive (Escarole)
1.6
0.05
0.05
0.05
0.05
Gai Lon
1.4
0.04
0.09
0.09
0.09
Pimento
1.2
0.03
0.03
0.03
0.03
Christmas Tree
1.2
0.04
0.05
0.05
0.05
Strawberry
1.0
0.34
0.43
0.43
0.43
N-Outdoor Flowers
0.9
0.05
0.09
0.09
0.09
Forest, Timberland
0.8
0.06
0.08
0.08
0.08
Fumigation (Other)
0.6
NS
NS
NS
NS
Bok Choy
0.6
0.04
0.04
0.04
0.04
Onion
0.4
0.02
0.02
0.02
0.02
Vegetable
0.2
0.07
0.07
0.07
0.07
Commodity
Fumigation
0.2
NS
NS
NS
NS
Sugarcane
0.2
0.05
0.05
0.05
0.05
Chinese Greens
0.1
0.03
0.03
0.03
0.03
Public Health
0.1
NS
NS
NS
NS
Stone Fruit
0.1
0.03
0.03
0.03
0.03
Celery
0.1
0.04
0.04
0.04
0.04
Industrial Site
0.0
0.04
0.04
0.04
0.04
Avocado
0.0
0.03
0.03
0.03
0.03
Pome Fruit
0.0
0.04
0.04
0.04
0.04
1 A zero represents a value less than 0.1 pounds.
2 Average pounds applied is the sum of the average annual pounds applied for a specific use/site between 2002 and
2005 for all counties.
3 NS stands for not specified.
Based on data reported in the CDPR PUR database, esfenvalerate application varies for different
months and crops (Figure 2-4, Figure 2-5, and APPENDIX G) Months with highest pounds of
esfenvalerate applied across California are January and July. These months coincide with all life
30
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cycles (young juveniles, tadpoles, and breeding/egg) of the CRLF and the high usage months for
almonds (Figure 2-5).
In addition to considering the amount applied each month, Figure 2-6 shows that the amount
applied for each use varies annually and may not follow a predictable trend. Over the four year
time frame, usage on almonds increased while usage for peach, tomato, corn, and artichoke was
relatively constant.
Figure 2-4. Comparison of phases of the California Red-legged Frog (CRLF) life cycle to
the average pounds esfenvalerate applied per month between 2003 and 2005.
8000
7000
6000
= S soon
4000
3000
¦4
Young Juveniles
V
Tadpoles
v
¦4
Breeding/Egg
2000
1000
t— —i— —r
Jar i Feb Mar Apr
t— —i— —I— —i— —i— —i— —r
May Juri Jul Auy Sep OcL Nov Dec
Application Month
31
-------
Figure 2-5. Timing of Esfenvalerate Application: Average number of pounds of active
ingredient applied in California for Almond and Peach, per month, between January 2002
through December 2005. Similar figures for other crops are available in.
73
.9! w
4000
3000
Almond
2000
— CM
^ O
ifl
73 CM
§ §
O ™
0. C
0) S
O) >
2 | 1000
® CD
<
0
n
n
a
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Application Month
1500
? m
£§
Q. CM
^ O
-------
Figure 2-6. Pounds of Esfenvalerate Applied Each Year by Crop.
"O
0)
9000
Q.
Q.
<
7500
-a
c
6000
3
O
CL
4500
rc
3
£
3000
<
>
o
<
~ 2002
~ 2003
~ 2004
~ 2005
Almond Peach Tomato Corn
Use Site/Crop
Artichoke
2.5 Assessed Species
The CRLF was federally listed as a threatened species by USFWS effective June 24, 1996
(USFWS 1996). It is one of two subspecies of the red-legged frog and is the largest native frog
in the western United States (USFWS 2002). A brief summary of information regarding CRLF
distribution, reproduction, diet, and habitat requirements is provided in Sections 2.5.1 through
2.5.4, respectively. Further information on the status, distribution, and life history of and
specific threats to the CRLF is provided in Attachment 1.
Final critical habitat for the CRLF was designated by USFWS on April 13, 2006 (USFWS 2006;
71 FR 19244-19346). Further information on designated critical habitat for the CRLF is
provided in Section 2.6.
2.5.1
Distribution
The CRLF is endemic to California and Baja California (Mexico) and historically inhabited 46
counties in California including the Central Valley and both coastal and interior mountain ranges
(USFWS 1996). Its range has been reduced by about 70%, and the species currently resides in
22 counties in California (USFWS 1996). The species has an elevational range of near sea level
to 1,500 meters (5,200 feet) (Jennings and Hayes 1994); however, nearly all of the known CRLF
populations have been documented below 1,050 meters (3,500 feet) (USFWS 2002).
Populations currently exist along the northern California coast, northern Transverse Ranges
(USFWS 2002), foothills of the Sierra Nevada (5-6 populations), and in southern California
south of Santa Barbara (two populations) (Fellers 2005a). Relatively larger numbers of CRLFs
are located between Marin and Santa Barbara Counties (Jennings and Hayes 1994). A total of
243 streams or drainages are believed to be currently occupied by the species, with the greatest
33
-------
numbers in Monterey, San Luis Obispo, and Santa Barbara counties (USFWS 1996). Occupied
drainages or watersheds include all bodies of water that support CRLFs (i.e., streams, creeks,
tributaries, associated natural and artificial ponds, and adjacent drainages), and habitats through
which CRLFs can move (i.e., riparian vegetation, uplands) (USFWS 2002).
The distribution of CRLFs within California is addressed in this assessment using four categories
of location including recovery units, core areas, designated critical habitat, and known
occurrences of the CRLF reported in the California Natural Diversity Database (CNDDB) that
are not included within core areas and/or designated critical habitat (see Figure 2-7). Recovery
units, core areas, and other known occurrences of the CRLF from the CNDDB are described in
further detail in this section, and designated critical habitat is addressed in Section 2.6. Recovery
units are large areas defined at the watershed level that have similar conservation needs and
management strategies. The recovery unit is primarily an administrative designation, and land
area within the recovery unit boundary is not exclusively CRLF habitat. Core areas are smaller
areas within the recovery units that comprise portions of the species' historic and current range
and have been determined by USFWS to be important in the preservation of the species.
Designated critical habitat is generally contained within the core areas, although a number of
critical habitat units are outside the boundaries of core areas, but within the boundaries of the
recovery units. Additional information on CRLF occurrences from the CNDDB is used to cover
the current range of the species not included in core areas and/or designated critical habitat, but
within the recovery units.
Recovery Units
Eight recovery units have been established by USFWS for the CRLF. These areas are
considered essential to the recovery of the species, and the status of the CRLF "may be
considered within the smaller scale of the recovery units, as opposed to the statewide range"
(USFWS 2002). Recovery units reflect areas with similar conservation needs and population
statuses, and therefore, similar recovery goals. The eight units described for the CRLF are
delineated by watershed boundaries defined by US Geological Survey hydrologic units and are
limited to the elevational maximum for the species of 1,500 m above sea level. The eight
recovery units for the CRLF are listed in Table 2-7 and shown in Figure 2-7.
Core Areas
USFWS has designated 35 core areas across the eight recovery units to focus their recovery
efforts for the CRLF (see Figure 2-7). Table 2-7 summarizes the geographical relationship
among recovery units, core areas, and designated critical habitat. The core areas, which are
distributed throughout portions of the historic and current range of the species, represent areas
that allow for long-term viability of existing populations and reestablishment of populations
within historic range. These areas were selected because they: 1) contain existing viable
populations; or 2) they contribute to the connectivity of other habitat areas (USFWS 2002). Core
area protection and enhancement are vital for maintenance and expansion of the CRLF's
distribution and population throughout its range.
34
-------
For purposes of this assessment, designated critical habitat, currently occupied (post-1985) core
areas, and additional known occurrences of the CRLF from the CNDDB are considered. Each
type of locational information is evaluated within the broader context of recovery units. For
example, if no labeled uses of esfenvalerate occur (or if labeled uses occur at predicted exposures
less than the Agency's LOCs) within an entire recovery unit, a "no effect" determination would
be made for all designated critical habitat, currently occupied core areas, and other known
CNDDB occurrences within that recovery unit. Historically occupied sections of the core areas
are not evaluated as part of this assessment because the USFWS Recovery Plan (USFWS 2002)
indicates that CRLFs are extirpated from these areas. A summary of currently and historically
occupied core areas is provided in Table 2-7 (currently occupied core areas are bolded). While
core areas are considered essential for recovery of the CRLF, core areas are not federally-
designated critical habitat, although designated critical habitat is generally contained within these
core recovery areas. It should be noted, however, that several critical habitat units are located
outside of the core areas, but within the recovery units. The focus of this assessment is currently
occupied core areas, designated critical habitat, and other known CNDDB CRLF occurrences
within the recovery units. Federally-designated critical habitat for the CRLF is further explained
in Section 2.6.
Table 2-7. California Red-legged Frog Recovery Units with Overlapping Core Areas and
Designated Critical Habitat
Recovery Unit1
(Figure 2-7)
Core Areas2'7 (Figure 2-7)
Critical Habitat
Units3
Currently
Occupied
(post-1985)4
Historically
Occupied 4
Sierra Nevada Foothills
and Central Valley (1)
(eastern boundary is the
1,500m elevation line)
Cottonwood Creek (partial) (8)
—
Feather River (1)
BUT-1A-B
Yuba River-S. Fork Feather
River (2)
YUB-1
—
NEV-16
Traverse Creek/Middle Fork
American River/Rubicon (3)
--
Consumnes River (4)
ELD-1
S. Fork Calaveras River (5)
—
Tuolumne River (6)
—
Piney Creek (7)
—
East San Francisco Bay
(partial)(16)
--
North Coast Range
Foothills and Western
Sacramento River
Valley (2)
Cottonwood Creek (8)
--
Putah Creek-Cache Creek (9)
--
Jameson Canyon - Lower Napa
Valley (partial) (15)
--
Belvedere Lagoon (partial) (14)
--
Pt. Reyes Peninsula (partial) (13)
--
35
-------
Recovery Unit1
(Figure 2-7)
Core Areas2'7 (Figure 2-7)
Critical Habitat
Units3
Currently
Occupied
(post-1985)4
Historically
Occupied 4
North Coast and North
San Francisco Bay (3)
Putah Creek-Cache Creek (partial)
(9)
--
Lake Berryessa Tributaries (10)
NAP-1
Upper Sonoma Creek (11)
—
Petaluma Creek-Sonoma Creek
(12)
--
Pt. Reyes Peninsula (13)
MRN-1, MRN-2
Belvedere Lagoon (14)
—
Jameson Canyon-Lower Napa
River (15)
SOL-1
South and East San
Francisco Bay (4)
—
CCS-1A6
East San Francisco Bay (partial)
(16)
ALA-1A, ALA-
IB, STC-1B
STC-1A6
South San Francisco Bay
(partial) (18)
SNM-1A
Central Coast (5)
South San Francisco Bay
(partial) (18)
SNM-1A, SNM-
2C, SCZ-1
Watsonville Slough- Elkhorn
Slough (partial) (19)
SCZ-2 5
Carmel River-Santa Lucia (20)
MNT-2
Estero Bay (22)
—
—
SLO-86
Arroyo Grande Creek (23)
—
Santa Maria River-Santa Ynez
River (24)
~
Diablo Range and
Salinas Valley (6)
East San Francisco Bay (partial)
(16)
MER-1A-B, STC-
1B
SNB-16, SNB-26
Santa Clara Valley (17)
~
Watsonville Slough- Elkhorn
Slough (partial)(19)
MNT-1
Carmel River-Santa Lucia
(partial)(20)
~
Gablan Range (21)
SNB-3
Estrella River (28)
SLO-1A-B
Northern Transverse
Ranges and Tehachapi
Mountains (7)
--
SLO-86
Santa Maria River-Santa Ynez
River (24)
STB-4, STB-5,
STB-7
Sisquoc River (25)
STB-1, STB-3
Ventura River-Santa Clara
River (26)
VEN-1, VEN-2,
VEN-3
36
-------
Recovery Unit1
(Figure 2-7)
Core Areas2'7 (Figure 2-7)
Critical Habitat
Units3
Currently
Occupied
(post-1985)4
Historically
Occupied 4
--
LOS-16
Southern Transverse and
Peninsular Ranges (8)
Santa Monica Bay-Ventura
Coastal Streams (27)
--
San Gabriel Mountain (29)
—
Forks of the Mojave (30)
—
Santa Ana Mountain (31)
—
Santa Rosa Plateau (32)
—
San Luis Rey (33)
—
Sweetwater (34)
—
Laguna Mountain (35)
—
1 Recovery units designated by the USFWS (USFWS 2000, pg 49).
2 Core areas designated by the USFWS (USFWS 2000, pg 51).
3 Critical habitat units designated by the USFWS on April 13, 2006 (USFWS 2006, 71 FR 19244-19346).
4 Currently occupied (post-1985) and historically occupied core areas as designated by the USFWS (USFWS 2002,
Pg 54).
5 Critical habitat unit where identified threats specifically included pesticides or agricultural runoff (USFWS 2002).
6 Critical habitat units that are outside of core areas, but within recovery units.
7 Currently occupied core areas that are included in this effects determination are bolded.
37
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Figure 2-7. Recovery Unit, Core Area, Critical Habitat, and Occurrence Designations for
CRLF
Otis
Legend
] Recovery Unit Boundaries
| Currently Occupied Core Areas
| Critical Habitat
¦ CNDDB Occurence Sections
County Boundaries
Recovery Units
1. Sierra Nevada Foothills and Central Valley
2. North Coast Range Foothills and Western
Sacramento River Valley
3. North Coast and North San Francisco Bay
4. South and East San Francisco Bay
5. Central Coast
6. Diablo Range and Salinas Valley
7. Northern Transverse Ranges and Tehachapi
Mountains
8. Southern Transverse and Peninsular Ranges
100 Miles
J I I
Core Areas
1. Feather River
19.
Watsonville Slough-Elkhorn Slough
2. Yuba River- S. Fork Feather River
20.
Carmel River - Santa Lucia
3. Traverse Creek/ Middle Fork/ American R. Rubicon
21.
Gablan Range
4. Cosumnes River
22.
Estero Bay
5. South Fork Calaveras River*
23.
Arroyo Grange River
6. Tuolumne River*
24.
Santa Maria River - Santa Ynez River
7. Piney Creek*
25.
Sisquoc River
8. Cottonwood Creek
26.
Ventura River - Santa Clara River
9. Putah Creek - Cache Creek*
27.
Santa Monica Bay - Venura Coastal Streams
10. Lake Berryessa Tributaries
28.
Estrella River
11. Upper Sonoma Creek
29.
San Gabriel Mountain*
12. Petaluma Creek - Sonoma Creek
30.
Forks of the Mojave*
13. Pt. Reyes Peninsula
31.
Santa Ana Mountain*
14. Belvedere Lagoon
32.
Santa Rosa Plateau
15. Jameson Canyon — Lower Napa River
33.
San Luis Ray*
16. East San Francisco Bay
34.
Sweetwater*
17. Santa Clara Valley
35.
Laguna Mountain*
18. South San Francisco Bay
* Core areas that were historically occupied by the California red-legged frog are not included in the map
38
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Other Known Occurrences from the CNDBB
The CNDDB provides location and natural history information on species found in California.
The CNDDB serves as a repository for historical and current species location sightings.
Information regarding known occurrences of CRLFs outside of the currently occupied core areas
and designated critical habitat is considered in defining the current range of the CRLF. See:
http://www.dfg.ca.gov/bdb/html/cnddb info.html for additional information on the CNDDB.
2.5.2 Reproduction
CRLFs breed primarily in ponds; however, they may also breed in quiescent streams, marshes,
and lagoons (Fellers 2005a). According to the Recovery Plan (USFWS 2002), CRLFs breed
from November through late April. Peaks in spawning activity vary geographically; Fellers
(2005b) reports peak spawning as early as January in parts of coastal central California. Eggs
are fertilized as they are being laid. Egg masses are typically attached to emergent vegetation,
such as bulrushes (Scirpus spp.) and cattails (Typha spp.) or roots and twigs, and float on or near
the surface of the water (Hayes and Miyamoto 1984). Egg masses contain approximately 2000
to 6000 eggs ranging in size between 2 and 2.8 mm (Jennings and Hayes 1994). Embryos hatch
10 to 14 days after fertilization (Fellers 2005a) depending on water temperature. Egg predation
is reported to be infrequent and most mortality is associated with the larval stage (particularly
through predation by fish); however, predation on eggs by newts has also been reported
(Rathburn 1998). Tadpoles require 11 to 28 weeks to metamorphose into juveniles (terrestrial-
phase), typically between May and September (Jennings and Hayes 1994, USFWS 2002);
tadpoles have been observed to over-winter (delay metamorphosis until the following year)
(Fellers 2005b, USFWS 2002). Males reach sexual maturity at 2 years, and females reach sexual
maturity at 3 years of age; adults have been reported to live 8 to 10 years (USFWS 2002). Figure
2-8 depicts CRLF annual reproductive timing.
Figure 2-8. CRLF Reproductive Events by Month
J
F
M
A
M
J
J
A
S
o
N
D
Light Blue = Breeding/Egg Masses
Green = Tadpoles (except those that over-winter)
Orange =
Adults and juveniles can be present all year
2.5.3 Diet
Although the diet of CRLF aquatic-phase larvae (tadpoles) has not been studied specifically, it is
assumed that their diet is similar to that of other frog species, with the aquatic phase feeding
exclusively in water and consuming diatoms, algae, and detritus (USFWS 2002). Tadpoles filter
39
-------
and entrap suspended algae (Seale and Beckvar, 1980) via mouthparts designed for effective
grazing of periphyton (Wassersug, 1984, Kupferberg el a/.; 1994; Kupferberg, 1997; Altig and
McDiarmid, 1999).
Juvenile and adult CRLFs forage in aquatic and terrestrial habitats, and their diet differs greatly
from that of larvae. The main food source for juvenile aquatic- and terrestrial-phase CRLFs is
thought to be aquatic and terrestrial invertebrates found along the shoreline and on the water
surface. Hayes and Tennant (1985) report, based on a study examining the gut content of 35
juvenile and adult CRLFs, that the species feeds on as many as 42 different invertebrate taxa,
including Arachnida, Amphipoda, Isopoda, Insecta, and Mollusca. The most commonly observed
prey species were larval alderflies (Sialis cf. californica), pillbugs (Armadilliadrium vulgare),
and water striders (Gerris sp). The preferred prey species, however, was the sowbug (Hayes and
Tennant, 1985). This study suggests that CRLFs forage primarily above water, although the
authors note other data reporting that adults also feed under water, are cannibalistic, and
consume fish. For larger CRLFs, over 50% of the prey mass may consists of vertebrates such as
mice, frogs, and fish, although aquatic and terrestrial invertebrates were the most numerous food
items (Hayes and Tennant 1985). For adults, feeding activity takes place primarily at night; for
juveniles feeding occurs during the day and at night (Hayes and Tennant 1985).
2.5.4 Habitat
CRLFs require aquatic habitat for breeding, but also use other habitat types including riparian
and upland areas throughout their life cycle. CRLF use of their environment varies; they may
complete their entire life cycle in a particular habitat or they may utilize multiple habitat types.
Overall, populations are most likely to exist where multiple breeding areas are embedded within
varying habitats used for dispersal (USFWS 2002). Generally, CRLFs utilize habitat with
perennial or near-perennial water (Jennings et al. 1997). Dense vegetation close to water,
shading, and water of moderate depth are habitat features that appear especially important for
CRLF (Hayes and Jennings 1988).
Breeding sites include streams, deep pools, backwaters within streams and creeks, ponds,
marshes, sag ponds (land depressions between fault zones that have filled with water), dune
ponds, and lagoons. Breeding adults have been found near deep (0.7 m) still or slow moving
water surrounded by dense vegetation (USFWS 2002); however, the largest number of tadpoles
have been found in shallower pools (0.26 - 0.5 m) (Reis, 1999). Data indicate that CRLFs do
not frequently inhabit vernal pools, as conditions in these habitats generally are not suitable
(Hayes and Jennings 1988).
CRLFs also frequently breed in artificial impoundments such as stock ponds, although additional
research is needed to identify habitat requirements within artificial ponds (USFWS 2002). Adult
CRLFs use dense, shrubby, or emergent vegetation closely associated with deep-water pools
bordered with cattails and dense stands of overhanging vegetation
(http://www.fws.gov/endangered/features/rl frog/rlfrog.html#where).
In general, dispersal and habitat use depends on climatic conditions, habitat suitability, and life
stage. Adults rely on riparian vegetation for resting, feeding, and dispersal. The foraging quality
40
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of the riparian habitat depends on moisture, composition of the plant community, and presence of
pools and backwater aquatic areas for breeding. CRLFs can be found living within streams at
distances up to 3 km (2 miles) from their breeding site and have been found up to 30 m (100 feet)
from water in dense riparian vegetation for up to 77 days (USFWS 2002).
During dry periods, the CRLF is rarely found far from water, although it will sometimes disperse
from its breeding habitat to forage and seek other suitable habitat under downed trees or logs,
industrial debris, and agricultural features (UWFWS 2002). According to Jennings and Hayes
(1994), CRLFs also use small mammal burrows and moist leaf litter as habitat. In addition,
CRLFs may also use large cracks in the bottom of dried ponds as refugia; these cracks may
provide moisture for individuals avoiding predation and solar exposure (Alvarez 2000).
2.6 Designated Critical Habitat
In a final rule published on April 13, 2006, 34 separate units of critical habitat were designated
for the CRLF by USFWS (USFWS 2006; FR 51 19244-19346). A summary of the 34 critical
habitat units relative to USFWS-designated recovery units and core areas (previously discussed
in Section 2.5.1) is provided in Table 2-7.
'Critical habitat' is defined in the ESA as the geographic area occupied by the species at the time
of the listing where the physical and biological features necessary for the conservation of the
species exist, and there is a need for special management to protect the listed species. It may
also include areas outside the occupied area at the time of listing if such areas are 'essential to
the conservation of the species.' All designated critical habitat for the CRLF was occupied at the
time of listing. Critical habitat receives protection under Section 7 of the ESA through
prohibition against destruction or adverse modification with regard to actions carried out, funded,
or authorized by a federal Agency. Section 7 requires consultation on federal actions that are
likely to result in the destruction or adverse modification of critical habitat.
To be included in a critical habitat designation, the habitat must be 'essential to the conservation
of the species.' Critical habitat designations identify, to the extent known using the best
scientific and commercial data available, habitat areas that provide essential life cycle needs of
the species or areas that contain certain primary constituent elements (PCEs) (as defined in 50
CFR 414.12(b)). PCEs include, but are not limited to, space for individual and population
growth and for normal behavior; food, water, air, light, minerals, or other nutritional or
physiological requirements; cover or shelter; sites for breeding, reproduction, rearing (or
development) of offspring; and habitats that are protected from disturbance or are representative
of the historic geographical and ecological distributions of a species. The designated critical
habitat areas for the CRLF are considered to have the following PCEs that justify critical habitat
designation:
• Breeding aquatic habitat;
• Non-breeding aquatic habitat;
• Upland habitat; and
• Dispersal habitat.
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Further description of these habitat types is provided in Attachment 1.
Occupied habitat may be included in the critical habitat only if essential features within the
habitat may require special management or protection. Therefore, USFWS does not include
areas where existing management is sufficient to conserve the species. Critical habitat is
designated outside the geographic area presently occupied by the species only when a
designation limited to its present range would be inadequate to ensure the conservation of the
species. For the CRLF, all designated critical habitat units contain all four of the PCEs, and were
occupied by the CRLF at the time of FR listing notice in April 2006. The FR notice designating
critical habitat for the CRLF includes a special rule exempting routine ranching activities
associated with livestock ranching from incidental take prohibitions. The purpose of this
exemption is to promote the conservation of rangelands, which could be beneficial to the CRLF,
and to reduce the rate of conversion to other land uses that are incompatible with CRLF
conservation. Please see Attachment 1 for a full explanation on this special rule.
USFWS has established adverse modification standards for designated critical habitat (USFWS
2006). Activities that may destroy or adversely modify critical habitat are those that alter the
PCEs and jeopardize the continued existence of the species. Evaluation of actions related to use
of esfenvalerate that may alter the PCEs of the CRLF's critical habitat form the basis of the
critical habitat impact analysis. According to USFWS (2006), activities that may affect critical
habitat and therefore result in adverse effects to the CRLF include, but are not limited to the
following:
(1) Significant alteration of water chemistry or temperature to levels beyond the tolerances of
the CRLF that result in direct or cumulative adverse effects to individuals and their life-
cycles.
(2) Significant increase in sediment deposition within the stream channel or pond or
disturbance of upland foraging and dispersal habitat that could result in elimination or
reduction of habitat necessary for the growth and reproduction of the CRLF by increasing
the sediment deposition to levels that would adversely affect their ability to complete
their life cycles.
(3) Significant alteration of channel/pond morphology or geometry that may lead to changes
to the hydrologic functioning of the stream or pond and alter the timing, duration, water
flows, and levels that would degrade or eliminate the CRLF and/or its habitat. Such an
effect could also lead to increased sedimentation and degradation in water quality to
levels that are beyond the CRLF's tolerances.
(4) Elimination of upland foraging and/or aestivating habitat or dispersal habitat.
(5) Introduction, spread, or augmentation of non-native aquatic species in stream segments or
ponds used by the CRLF.
(6) Alteration or elimination of the CRLF's food sources or prey base (also evaluated as
indirect effects to the CRLF).
As previously noted in Section 2.1, the Agency believes that the analysis of direct and indirect
effects to listed species provides the basis for an analysis of potential effects on the designated
critical habitat. Because esfenvalerate is expected to directly impact living organisms within the
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action area, critical habitat analysis for esfenvalerate is limited in a practical sense to those PCEs
of critical habitat that are biological or that can be reasonably linked to biologically mediated
processes.
2.7 Action Area
For listed species assessment purposes, the action area is considered to be the area affected
directly or indirectly by the federal action and not merely the immediate area involved in the
action (50 CFR 402.02). It is recognized that the overall action area for the national registration
of esfenvalerate is likely to encompass considerable portions of the United States based on the
large array of agricultural and non-agricultural uses. However, the scope of this assessment
limits consideration of the overall action area to those portions that may be applicable to the
protection of the CRLF and its designated critical habitat within the state of California. Deriving
the geographical extent of this portion of the action area is based on consideration of the types of
effects that esfenvalerate may be expected to have on the environment, the exposure levels to
esfenvalerate that are associated with those effects, and the best available information concerning
the use of esfenvalerate and its fate and transport within the state of California.
The definition of action area requires a stepwise approach that begins with an understanding of
the federal action. The federal action is defined by the currently labeled uses for esfenvalerate.
An analysis of labeled uses and review of available product labels was completed. Several of the
currently labeled uses are special local needs (SLN) or are restricted to specific states other than
California and are excluded from this assessment. In addition, a distinction has been made
between food use crops and those that are non-food/non-agricultural uses. For those uses
relevant to the CRLF, the analysis indicates that, for esfenvalerate, the agricultural uses
considered as part of the federal action evaluated in this assessment are listed in Table 2-3 and
the non-food and non-agricultural uses are listed in Table 2-4. Table 2-4 lists indoor uses, which
result in incomplete exposure pathways and/or, because of scale, are highly unlikely to result in
meaningful measurable effects to the CRLF or its designated critical habitat. They were
qualitatively assessed to have "No Effect" based on professional judgment and are therefore not
evaluated further.
Following a determination of the assessed uses, an evaluation of the potential "footprint" of
esfenvalerate use patterns is determined. This "footprint" represents the initial area of concern
based on an analysis of available land cover data for the state of California. The initial area of
concern is typically defined as all land cover types and the stream reaches within the land cover
areas that represent the labeled uses described above. However, the overall conclusion of the
analyses of esfenvalerate uses is that there is no area in California from which the possibility of
the occurrence of esfenvalerate applications can be excluded. Therefore, the initial area of
concern, defined as all land cover types that represent the labeled uses of esfenvalerate included
in this assessment, is presumed to encompasses essentially the entire state of California.
Once the initial area of concern is defined, the next step is to compare the extent of that area with
the results of the screening-level risk assessment. The screening-level risk assessment identifies
which taxa, if any, are predicted to be exposed at concentrations above the Agency's Levels of
Concern (LOC). The screening-level assessment includes an evaluation of the environmental
fate properties of esfenvalerate to determine which routes of transport are likely to have an
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impact on the CRLF. An analysis of the environmental fate is presented above in Section 2.4.1;
however, it is supposed that the uses of esfenvalerate will result in exposure across all CRLF
habitat. Therefore, based on LOC exceedances, the action area encompasses both the aquatic
and terrestrial portions of the CRLF habitat including designated critical habitat.
2.8 Assessment Endpoints and Measures of Ecological Effect
Assessment endpoints are defined as "explicit expressions of the actual environmental value that
is to be protected."20 Selection of the assessment endpoints is based on valued entities (e.g.,
CRLF, organisms important in the life cycle of the CRLF, and the PCEs of its designated critical
habitat), the ecosystems potentially at risk (e.g., waterbodies, riparian vegetation, and upland and
dispersal habitats), the migration pathways of esfenvalerate (e.g., runoff, spray drift, etc.), and
the routes by which ecological receptors are exposed to esfenvalerate-related contamination (e.g.,
direct contact, etc.).
2.8.1 Assessment Endpoints for the CRLF
Assessment endpoints for the CRLF include direct toxic effects on the survival, reproduction,
and growth of the CRLF, as well as indirect effects, such as reduction of the prey base or
modification of its designated critical habitat. In addition, potential modification of critical
habitat is assessed by evaluating potential effects to PCEs, which are components of the habitat
areas that provide essential life cycle needs of the CRLF. Each assessment endpoint requires one
or more "measures of ecological effect," defined as changes in the attributes of an assessment
endpoint or changes in a surrogate entity or attribute in response to exposure to a pesticide.
Specific measures of ecological effect are generally evaluated based on acute and chronic
toxicity information from registrant-submitted guideline tests that are performed on a limited
number of organisms. Additional ecological effects data from the open literature are also
considered.
A complete discussion of all the toxicity data available for this risk assessment, including
resulting measures of ecological effect selected for each taxonomic group of concern, is included
in Section 4.0 of this document. A summary of the assessment endpoints and measures of
ecological effect selected to characterize potential assessed direct and indirect CRLF risks
associated with exposure to esfenvalerate is provided in Table 2-8. Data were not available to
quantitatively assess the risk of esfenvalerate to aquatic and terrestrial plants; however,
qualitative information gathered from studies in ECOTOX provided some information that was
used in making determinations for these taxa. Since fenvalerate is closely-related to
esfenvalerate, studies on this chemical will be used if they provide more sensitive endpoints than
esfenvalerate.
20FromU.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.
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Table 2-8. Summary of Assessment Endpoints and Measures of Ecological Effects for
Direct and Indirect Effects of Esfenvalerate on the CRLF.
Assessment Endpoint
21
Measures of Ecological Effects
Data Sought
Final Selection
Aquatic Phase
(eggs, larvae, tadpoles, juveniles, and adults)^
1. Survival, growth, and
reproduction of CRLF individuals
via direct effects on aquatic phases
la. Most sensitive fish acute LC50
if no suitable amphibian data are
available
la. Esfenvalerate, Rainbow trout 96-hr
LC50 0.07 ppb ai (source: -guideline
study, no appropriate amphibian data
were available)
lb. Most sensitive fish early-life
stage NOAEC if no suitable
amphibian early life stage data are
available
lb. Esfenvalerate, freshwater fish
NOAEC 0.035 ppb-ai (source: estimated
using an acute-to-chronic ratio (ACR);
no appropriate amphibian data were
available)
2. Survival, growth, and
reproduction of CRLF individuals
via effects to food supply (i.e.,
freshwater invertebrates, non-
vascular plants)
2a. Most sensitive (1) fish LC50:
(2) aquatic invertebrate LC50 or
EC50; and (3) aquatic benthic
invertebrate LC50 or EC50
2a(1) Esfenvalerate, Rainbow trout 96-hr
LC50 0.07 ppb ai (source: guideline
study)
2a(2) Fenvalerate, waterflea 48-hr EC50
0.05 ppb ai (source: guideline study)
2a(3) No benthic invertebrate sediment
data
2b. Most sensitive (1) fish early-life
stage NOAEC; and (2) aquatic
invertebrate chronic NOAEC
2b(1) Esfenvalerate, freshwater fish
early life stage NOAEC 0.035 ppb ai
(source: estimated using an ACR derived
from guideline studies)
2b (2) Esfenvalerater, waterflea life cycle
NOAEC 0.017 ppb ai (source: estimated
using an ACR derived from guideline
studies)
3. Survival, growth, and
reproduction of CRLF individuals
via indirect effects on habitat,
cover, and/or primary productivity
(i.e., aquatic plant community)
.3a. Vascular plant acute EC50
(duckweed guideline test or
ECOTOX vascular plant)
3 a and 3b. No quantitative data available
for vascular or non-vascular aquatic
plants
3b. Non-vascular plant acute EC50
(freshwater algae or diatom, or
ECOTOX non-vascular)
4. Survival, growth, and
reproduction of CRLF individuals
via effects to riparian vegetation,
required to maintain acceptable
water quality and habitat in ponds
and streams comprising the
species' current range.
4a. Distribution of EC25 values for
monocots (seedling emergence,
vegetative vigor, or ECOTOX)
4a and 4b. No quantitative data available
for terrestrial plants22
4b. Distribution of EC25 values for
dicots (seedling emergence,
vegetative vigor, or ECOTOX)23
21 All registrant-submitted and open literature toxicity data reviewed for this assessment are included in Section 4.0
22 The available information indicates that the California red-legged frog does not have any obligate relationships.
23 The available information indicates that the California red-legged frog does not have any obligate relationships.
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Assessment Endpoint
21
Measures of Ecological Effects
Data Sought
Final Selection
Terrestrial Phase (Juveniles and adults)
5. Survival, growth, and
reproduction of CRLF individuals
via direct effects on terrestrial
phase adults and juveniles
5a. Most sensitive birdb : (1) acute
LC50 and (2) LD50 if terrestrial-
phase amphibian data not available
5a(1). Esfenvalerate, Northern bobwhite
acute oral LD50 381 mg ai/kg-bw
(source: guideline study)
5a(2) Esfenvalerate, Mallard 5-d dietary
exposure LC50 4894 ppm ai (source:
guideline study)
5b. Most sensitive birdb chronic
NOAEC if terrestrial-phase
amphibian data not available
5b. No studies available
6. Survival, growth, and
reproduction of CRLF individuals
via effects on prey (i.e., terrestrial
invertebrates, small terrestrial
vertebrates, including mammals
and terrestrial phase amphibians)
6a. Most sensitive (1) terrestrial
invertebrate LD50 or ED50: and (2)
mammal acute LD50 or LC50; and
(3) birdb acute LC50 and LD50 c
6a(1). Esfenvalerate, Honey bee acute
contact LD50 0.017 ug/bee (source:
guideline study
6a(2) Esfenvalerate, laboratory rat acute
oral LD50 59.0 mg/kg-bw (source:
guideline study)
6a(3) Esfenvalerate, acute oral LD50 381
mg ai/kg-bw and mallard 5-d dietary
LC5o (source: guideline studies)
6b. Most sensitive (1) mammal two-
generation NOAEL or NOAEC; and
(2) birdb chronic NOAEC
6b (1). Esfenvalerate, laboratory rat
reproductive NOAEL 4.21 mg/kg-bw/d
(source: guideline study)
6b (2) no study available
7. Survival, growth, and
reproduction of CRLF individuals
via indirect effects on habitat (i.e.,
riparian vegetation)
7a. Distribution of EC25 for
monocots (seedling emergence,
vegetative vigor, or ECOTOX
7b. Distribution of EC25 for dicots
(seedling emergence, vegetative
vigor, or ECOTOX)
7a and 7b No quantitative data available
for terrestrial plants
a Adult frogs are no longer in the "aquatic phase" of the amphibian life cycle; however, submerged adult frogs are
considered "aquatic" for the purposes of this assessment because exposure pathways in the water are considerably
different than exposure pathways on land.
b Birds are used as surrogates for terrestrial-phase amphibians.
c Although the most sensitive toxicity value is initially used to evaluate potential indirect effects, sensitivity
distribution is used (if sufficient data are available) to evaluate the potential impact to food items of the CRLF.
2.8.2 Assessment Endpoints for Designated Critical Habitat
As previously discussed, designated critical habitat is assessed to evaluate actions related to the
use of esfenvalerate that may alter the PCEs of the CRLF's critical habitat. PCEs for the CRLF
were previously described in Section 2.6. Actions that may modify critical habitat are those that
alter the PCEs. Therefore, these actions are identified as assessment endpoints. It should be
noted that evaluation of PCEs as assessment endpoints is limited to those of a biological nature
{i.e., the biological resource requirements for the listed species associated with the critical
habitat) and those for which esfenvalerate effects data are available.
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Modification to the critical habitat of the CRLF includes the following, as specified by USFWS
(2006) and previously discussed in Section 2.6:
1. Alteration of water chemistry/quality including temperature, turbidity, and oxygen
content necessary for normal growth and viability of juvenile and adult CRLFs.
2. Alteration of chemical characteristics necessary for normal growth and viability of
juvenile and adult CRLFs.
3. Significant increase in sediment deposition within the stream channel or pond or
disturbance of upland foraging and dispersal habitat.
4. Significant alteration of channel/pond morphology or geometry.
5. Elimination of upland foraging and/or aestivating habitat, as well as dispersal habitat.
6. Introduction, spread, or augmentation of non-native aquatic species in stream segments or
ponds used by the CRLF.
7. Alteration or elimination of the CRLF's food sources or prey base.
Measures of such possible effects by labeled use of esfenvalerate on designated critical habitat of
the CRLF are described in Table 2-9. Some components of these PCEs are associated with
physical abiotic features (e.g., presence and/or depth of a water body, or distance between two
sites), which are not expected to be measurably altered by use of pesticides. Assessment
endpoints used for the analysis of designated critical habitat are based on the adverse
modification standard established by USFWS (2006).
Table 2-9. Summary of Assessment Endpoints and Measures of Ecological Effect for
Primary Constituent Elements of Designated Critical Habitat.
Assessment Endpoint
24
Measures of Ecological Effect
Data Sought
Selected Values
Aquatic Phase PCEs
(Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)
Alteration of channel/pond
morphology or geometry and/or
increase in sediment deposition
within the stream channel or
pond: aquatic habitat (including
riparian vegetation) provides for
shelter, foraging, predator
avoidance, and aquatic dispersal
for juvenile and adult CRLFs.
a. Most sensitive aquatic plant EC50
(guideline or ECOTOX)
b. Distribution of EC25 values for
terrestrial monocots (seedling
emergence, vegetative vigor, or
ECOTOX)
c. Distribution of EC25 values for
terrestrial dicots (seedling
emergence, vegetative vigor, or
ECOTOX)
a, b, and c: No aquatic or terrestrial plant
data were available; ancillary information
24 All toxicity data reviewed for this assessment are included in Section 4.0.
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Assessment Endpoint
24
Measures of Ecological Effect
Data Sought
Selected Values
Alteration in water
chemistry/quality including
temperature, turbidity, and
oxygen content necessary for
normal growth and viability of
juvenile and adult CRLFs and
their food source.25
a. Most sensitive EC50 values for
aquatic plants (guideline or
ECOTOX)
a, b, and c: No aquatic or terrestrial plant
data were available; ancillary information is
used
b. Distribution of EC25 values for
terrestrial monocots (seedling
emergence or vegetative vigor, or
ECOTOX)
c. Distribution of EC25 values for
terrestrial dicots (seedling
emergence, vegetative vigor, or
ECOTOX)
Alteration in water
chemistry/quality including
temperature, turbidity, and
oxygen content necessary for
normal growth and viability of
juvenile and adult CRLFs and
their food source.26
a. Most sensitive EC50 value for
aquatic plants (source; guideline or
ECOTOX)
a, b, and c: No aquatic or terrestrial plant
data were available; ancillary information is
used
b. Distribution of terrestrial
monocot (1) seedling emergence
EC25 values; and (2) vegetative
vigor EC25 values (source:
guidelines or ECOTOX)
c. Distribution of terrestrial dicot
(1) seedling emergence EC25 values;
and (2) vegetative vigor EC25 values
(source: guidelines or ECOTOX)
Alteration of other chemical
characteristics necessary for
normal growth and viability of
CRLFs and their food source.
a. Most sensitive acute (1) LC50
values for fish; and (2) acute LC50
or EC50 values for aquatic
invertebrates (including benthic
invertebrates)
a(1) Esfenvalerate, Rainbow trout 96-hr
LC50 0.07 ppb ai (source: guideline study)
a(2) Fenvalerate, waterflea 48-hr EC50 0.05
ppb ai (source: guideline study)
b. Most sensitive NOAEC values
for (1) fish; and (2) aquatic
invertebrates (source: guideline
data)
b(1) Esfenvalerate, freshwater fish, early
life stage NOAEC 0.035 ppb ai (source:
estimated using an ACR derived from
guideline studies)
b(2) Esfenvalerate, waterflea, life cycle
NOAEC 0.017 ppb ai (source: estimated
using an ACR derived from guideline
studies)
Reduction and/or modification
of aquatic-based food sources
for pre-metamorphs (e.g., algae)
Most sensitive aquatic plant EC50
(source: guideline or ECOTOX)
No aquatic plant data were available;
ancillary information used
9 Physico-chemical water quality parameters such as salinity, pH, and hardness are not evaluated because these
processes are not biologically mediated and, therefore, are not relevant to the endpoints included in this assessment.
26 Physico-chemical water quality parameters such as salinity, pH, and hardness are not evaluated because these
processes are not biologically mediated and, therefore, are not relevant to the endpoints included in this assessment.
48
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Assessment Endpoint
24
Measures of Ecological Effect
Data Sought
Selected Values
Terrestrial Phase PCEs
(Upland Habitat and Dispersal Habitat)
Elimination and/or disturbance
of upland habitat; ability of
habitat to support food source of
CRLFs: Upland areas within
200 ft of the edge of the riparian
vegetation or dripline
surrounding aquatic and riparian
habitat that are comprised of
grasslands, woodlands, and/or
wetland/riparian plant species
that provides the CRLF shelter,
forage, and predator avoidance
a. Most sensitive terrestrial food
source^ acute LC50 or LD50 and
chronic NOAEL values for
mammals; (2) acute LC50 orLD50
and chronic NOAEL for birds; (3)
acute LC50 or LD50 for terrestrial
invertebrates; (4) acute LC50 and
chronic NOAEC for freshwater fish;
and (5) acute LC50 or EC50 and
chronic NOAEC for aquatic
invertebrates
a(1) Esfenvalerate, laboratory rat acute oral
LD50 59 mg/kg-bw (source: guideline
study)
a(2) Esfenvalerate, Northern bobwhite
acute oral LD50 381 mg/kg-bw (source:
guideline study)
Elimination and/or disturbance
of dispersal habitat: Upland or
riparian dispersal habitat within
designated units and between
occupied locations within 0.7 mi
of each other that allow for
movement between sites
including both natural and
altered sites which do not
contain barriers to dispersal
a(3) Esfenvalerate, Honey bee acute contact
LD50 0.017 ug/bee
a(4) Esfenvalerate, Rainbow trout 96-hr
LC50 0.017 ppb ai (source: guideline
study)
Esfenvalerate, freshwater fish, early life
stage NOAEC 0.035 ppb ai (source:
estimated using an ACR derived from
guideline studies
Reduction and/or modification
of food sources for terrestrial
phase juveniles and adults
a(5) Esfenvalerate, waterflea 48-hr EC50
0.05 ppb ai (source: guideline study)
Esfenvalerate, waterflea life cycle NOAEC
0.017 ppb ai (source: estimated using an
ACR derived from guideline studies)
Alteration of chemical
characteristics necessary for
normal growth and viability of
juvenile and adult CRLFs and
their food source.
2.9 Conceptual Model
2.9.1 Risk Hypotheses
Risk hypotheses are specific assumptions about potential adverse effects {i.e., changes in
assessment endpoints) and may be based on theory and logic, empirical data, mathematical
models, or probability models (U.S. EPA, 1998). For this assessment, the risk is stressor-linked,
where the stressor is the release of esfenvalerate to the environment. The following risk
hypotheses are presumed for this endangered species assessment:
• Labeled uses of esfenvalerate within the action area may directly affect the CRLF by
causing mortality or by affecting growth or fecundity;
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• Labeled uses of esfenvalerate within the action area may indirectly affect the CRLF by
reducing or changing the composition of food supply;
• Labeled uses of esfenvalerate within the action area may indirectly affect the CRLF or
modify designated critical habitat by reducing or changing the composition of the aquatic plant
community in the ponds and streams comprising the species' current range and designated
critical habitat, thus affecting primary productivity or cover;
• Labeled uses of esfenvalerate within the action area may indirectly affect the CRLF or
modify designated critical habitat by reducing or changing the composition of the terrestrial plant
community {i.e., riparian habitat) required to maintain acceptable water quality and habitat in the
ponds and streams comprising the species' current range and designated critical habitat;
• Labeled uses of esfenvalerate within the action area may modify the designated critical
habitat of the CRLF by reducing or changing breeding and non-breeding aquatic habitat (via
modification of water quality parameters, habitat morphology, or sedimentation);
• Labeled uses of esfenvalerate within the action area may modify the designated critical
habitat of the CRLF by reducing the food supply required for normal growth and viability of
juvenile and adult CRLFs;
• Labeled uses of esfenvalerate within the action area may modify the designated critical
habitat of the CRLF by reducing or changing upland habitat within 200 ft of the edge of the
riparian vegetation necessary for shelter, foraging, and predator avoidance.
• Labeled uses of esfenvalerate within the action area may modify the designated critical
habitat of the CRLF by reducing or changing dispersal habitat within designated units and
between occupied locations within 0.7 mi of each other that allow for movement between sites
including both natural and altered sites which do not contain barriers to dispersal.
• Labeled uses of esfenvalerate within the action area may adversely modify the designated
critical habitat of the CRLF by altering chemical characteristics necessary for normal growth and
viability of juvenile and adult CRLFs.
2.9.2 Diagram
The conceptual model is a graphic representation of the structure of the risk assessment. It
specifies the stressor (esfenvalerate), release mechanisms, biological receptor types, and effects
endpoints of potential concern. The conceptual models for aquatic and terrestrial phases of the
CRLF are shown in Figure 2-9 and Figure 2-10, respectively, and the conceptual models for the
aquatic and terrestrial PCE components of critical habitat are shown in Figure 2-1 land Figure
2-12, respectively. Exposure routes shown in dashed lines are not quantitatively considered
because the contribution of those potential exposure pathways to potential risk to the CRLF and
modification to designated critical habitat is expected to be negligible.
50
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Figure 2-9. Conceptual Model for Pesticide Effects on Aquatic-Phase of the CRLF
51
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Figure 2-10. Conceptual Model for Pesticide Effects on Terrestrial-Phase of the CRLF
Stressor
Source
Exposure
Media
Pesticide applied to use site
Spray drift
-fp—Dermal uptake/I ingestion*—
Root
Runoff
Soil
Terrestrial/riparian plants
grasses/Forbs, fruit, seeds
(trees, shrubs)
uptake*-'
T
t
Long range
atmospheric
transport
¦ Wet/dry deposition*- ¦
Ingestion
Ingestion,
Ingestion
Mammals
Receptors
Red-legged Frog[,
Juvenile
Adult
Attribute
Change
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Food chain
Reduction in prey
Habitat integrity
Reduction in primary productivity
Reduced cover
Community change
52
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Figure 2-11. Conceptual Model for Pesticide Effects on Aquatic Components of CRLF
Critical Habitat
Stressor
Source
Exposure
Media
Pesticide applied to use site
Spray drift
Runoff
Soil
A I
'
Surface water/
Sediment
- Groundwater j i
! I
. mm mm wm wm mm 4 ^
¦ Wet/dry deposition-
Long range
atmospheric
transport
Receptors
Uptake/gills
or integument
1
Red-legged Frog
Eggs Juveniles
Larvae Adult
T adpoles
Uptake/gills
or integument
Aquatic Animals
Invertebrates
Vertebrates
--Ingestion
Attribute
Change
Habitat
PCEs
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
T
Other chemical
characteristics
Adversely modified
chemical characteristics
Uptake/cell,
roots, leaves
_i
Aquatic Plants
Non-vascular
Vascular
*
Ingestion
Riparian and
Upland plants
terrestrial exposure
pathways and PCEs
see Figure 2-12
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Population
Yield
Reduced yield
Community
Reduced seedling
emergence or vegetative
vigor (Distribution)
1
Food sources
Reduction in algae
Reduction in prey
- Habitat quality and channel/pond
morphology or geometry
- Adverse water quality changes
Increased sedimentation
Reduced shelter
53
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Figure 2-12. Conceptual Model for Pesticide Effects on Terrestrial Components of the
CRLF Critical Habitat
Stressor
Source
Exposure
Media and
Receptors
Pesticide applied to use site
Direct
application
Spray drift
-fp—Dermal uptake/Ingestion-
Root
Terrestrial plants
grasses/Forbs, fruit,
seeds (trees, shrubs)
Runoff
Soil
uptake ~-!
7
t
Long range
atmospheric
transport
¦ Wet/dry deposition*-
Ingestion
Ingestion
Red-legged Frog
Juvenile
Adult
Ingestion
J— Ingestion-
Attribute
Change
Habitat
PCEs
Individual organisms
Reduced survival
Reduced growth
Reduced reproduction
Other chemical
characteristics
Adversely modified
chemical characteristics
Mammals
f 1_
Population
Reduced survival
Reduced growth
Reduced reproduction
Food resources
Reduction in food
sources
Community
Reduced seedling emergence
or vegetative vigor
(Distribution)
Elimination and/or disturbance of
upland or dispersal habitat
Reduction in primary productivity
Reduced shelter
Restrict movement
54
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2.10 Analysis Plan
In order to address the risk hypotheses, the potential for direct and indirect effects to the CRLF,
its prey, and its habitat is estimated. In the following sections, the use, environmental fate, and
ecological effects of esfenvalerate are characterized and integrated to assess the risks. This is
accomplished using a risk quotient (ratio of exposure concentration to effects concentration)
approach. Although risk is often defined as the likelihood and magnitude of adverse ecological
effects, the risk quotient-based approach does not provide a quantitative estimate of likelihood
and/or magnitude of an adverse effect. However, as outlined in the Overview Document (U.S.
EPA, 2004), the likelihood of effects to individual organisms from particular uses of
esfenvalerate is estimated using the probit dose-response slope and either the level of concern
(discussed below) or actual calculated risk quotient value.
2.10.1 Measures to Evaluate the Risk Hypotheses and Conceptual Model
2.10.1.1 Measures of Exposure
The environmental fate properties of esfenvalerate along with available monitoring data indicate
that runoff/erosion and spray drift are the principle potential transport mechanisms of
esfenvalerate to the aquatic and terrestrial habitats of the CRLF. Because esfenvalerate has a
strong tendency to sorb to soil (based on the Kd/Koc values), the transport of esfenvalerate from
the field to water via runoff/erosion is most likely to occur with sediment. Esfenvalerate
exposure in water is likely to occur both in the water column and in the pore water/ benthic
sediment. In this assessment, transport of esfenvalerate through runoff/erosion and spray drift is
considered in deriving quantitative estimates of esfenvalerate exposure to CRLF, its prey and its
habitats.
Measures of exposure are based on aquatic and terrestrial models that predict estimated
environmental concentrations (EECs) of esfenvalerate using maximum labeled application rates
and methods of application. The models used to predict aquatic EECs are the Pesticide Root
Zone Model coupled with the Exposure Analysis Model System (PRZM/EXAMS). The model
used to predict terrestrial EECs on food items is T-REX. These models are parameterized using
relevant reviewed registrant-submitted environmental fate data. A model is also available to
estimate EECs relevant to terrestrial and wetland plants; however, toxicity values are not
available for calculation of RQs, so a qualitative judgment will be made based on information
presented in Section 4.0.
PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, April 2005) are screening simulation
models coupled with the input shell pe5.pl (Aug 2007) to generate daily exposures and l-in-10
year EECs of esfenvalerate that may occur in surface water bodies adjacent to application sites
receiving esfenvalerate through runoff and spray drift. PRZM simulates pesticide application,
movement and transformation on an agricultural field and the resultant pesticide loadings to a
receiving water body via runoff, erosion and spray drift. EXAMS simulates the fate of the
pesticide and resulting concentrations in the water body. The standard scenario used for
ecological pesticide assessments assumes application to a 10-hectare agricultural field that drains
into an adjacent 1-hectare surface water body, 2-meters deep (20,000 m3 volume) with no outlet.
55
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PRZM/EXAMS was used to estimate screening-level exposure of aquatic organisms to
esfenvalerate. The measure of exposure for aquatic species is the l-in-10 year return peak or
rolling mean concentration. The l-in-10 year peak is used for estimating acute exposures of
direct effects to the CRLF, as well as indirect effects to the CRLF through effects to potential
prey items, including: algae, aquatic invertebrates, fish and frogs. The 1-in-10-year 60-day mean
is used for assessing chronic exposure to the CRLF and fish and frogs serving as prey items; the
l-in-10-year 21-day mean is used for assessing chronic exposure for aquatic invertebrates, which
are also potential prey items.
Given the aquatic toxicity of esfenvalerate and its likelihood of occurring in sediment, the
Agency also considered the potential exposures resulting from benthic/sediment concentrations
(EECs). Pore water concentrations are commonly used to predict toxicity of non-ionic
substances in sediments and characterize exposure to organisms that spend time in or near
sediments (Di Toro et al. 1991; US EPA 2003). PRZM/EXAMS also estimates l-in-10-year
peak, 21-day mean, and 60-day mean EECs for pore water. Total sediment concentrations may
also be used to predict exposure to organisms. For example, total sediment concentrations may
be used to predict exposure from ingested sediment. Total sediment concentrations were
characterized based on monitoring data. These estimated EECs can be used to calculate risk
quotients to determine possible risks.
Several label uses for esfenvalerate specify spray drift reduction buffers, which can affect peak
aquatic EECs. The fraction spray drift used in PRZM/EXAMS was estimated based on the
buffers and application methods specified on the labels using AgDRIFT. For aerial applications,
very fine to fine drop size for ultra low volume applications and a buffer of 450 feet was
assumed. For ground applications, a fine to medium drop size, high boom, and 25 foot buffer
was assumed. These are the uses that predicted the highest fractions of spray drift for all of the
use and buffer combinations specified on the labels.
Exposure estimates for the terrestrial-phase CRLF and terrestrial invertebrates and mammals
(serving as potential prey) assumed to be in the target area or in an area exposed to spray drift are
derived using the T-REX model (version 1.3.1, 12/07/2006). This model incorporates the
Kenega nomograph, as modified by Fletcher et al. (1994), which is based on a large set of actual
field residue data. The upper limit values from the nomograph represents the 95th percentile of
residue values from actual field measurements (Hoerger and Kenega, 1972). For modeling
purposes, direct exposures of the CRLF to esfenvalerate through residues on food are estimated
using the EECs for the small bird (20 g), comparable to a young CRLF, which consumes small
insects. Dietary-based and dose-based exposures of potential small mammalian prey of the
CRLF are assessed using a 15 g small mammal which consumes short grass (dietary item with
highest residue level). The small bird (20g) consuming small insects and the small mammal
(15g) consuming short grass are used because these categories represent the largest RQs of the
size and dietary categories in T-REX that are appropriate surrogates for the CRLF and one of its
prey items. The estimated residues on small insects and large insects in T-REX are used as the
estimated exposures for terrestrial insects to esfenvalerate.
Birds are currently used as surrogates for terrestrial-phase CRLF. However, amphibians are
poikilotherms (body temperature varies with environmental temperature) while birds are
56
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homeotherms (temperature is regulated, constant, and largely independent of environmental
temperatures). Therefore, amphibians tend to have much lower metabolic rates and lower caloric
intake requirements than birds or mammals. As a consequence, birds are likely to consume more
food than amphibians on a daily dietary intake basis, assuming similar caloric content of the food
items. Therefore, the use of avian food intake allometric equation as a surrogate to amphibians is
likely to result in an over-estimation of dose-based exposure and risk for reptiles and terrestrial-
phase amphibians. Therefore, T-REX (version 1.3.1) has been refined to the T-HERPS model
(v. 1.0), which allows for an estimation of food intake for poikilotherms using the same basic
procedure as T-REX to estimate avian food intake.
2.10.1.2 Measures of Effect
Data identified in Section 2.8 are used as measures of effect for direct and indirect effects to the
CRLF. Data were obtained from registrant submitted studies or from literature studies identified
by ECOTOX. The ECOTOXicology database (ECOTOX) was searched in order to provide more
ecological effects data and in an attempt to bridge existing data gaps. ECOTOX is a source for
locating single chemical toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX
was created and is maintained by the USEPA, Office of Research and Development, and the
National Health and Environmental Effects Research Laboratory's Mid-Continent Ecology
Division.
The assessment of risk for direct effects to the terrestrial-phase CRLF makes the assumption that
toxicity of esfenvalerate to birds is similar to or less than the toxicity to the terrestrial-phase
CRLF. The same assumption is made for fish and aquatic-phase CRLF. Algae, aquatic
invertebrates, fish, and amphibians represent potential prey of the CRLF in the aquatic habitat.
Terrestrial invertebrates, small mammals, and terrestrial-phase amphibians represent potential
prey of the CRLF in the terrestrial habitat. Aquatic, semi-aquatic, and terrestrial plants represent
habitat of CRLF.
The acute measures of effect used for animals in this screening level assessment are the LD50,
LC50 and ECso- LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at
once, that is estimated to cause the death of 50% of the test organisms. LC stands for "Lethal
Concentration" and LC50 is the concentration of a chemical that is estimated to kill 50% of the
test organisms. EC stands for "Effective Concentration" and the EC50 is the concentration of a
chemical that is estimated to produce a specific effect in 50% of the test organisms. Endpoints
for chronic measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and
NOEC. NOAEL stands for "No Ob served-Adverse-Effect-Level" and refers to the highest tested
dose of a substance that has been reported to have no harmful (adverse) effects on test
organisms. The NOAEC {i.e., "No-Observed-Adverse-Effect-Concentration") is the highest test
concentration at which none of the observed effects were statistically different from the control.
The NOEC is the No-Observed-Effects-Concentration. For non-listed plants, only acute
exposures are assessed {i.e., EC25 for terrestrial plants and EC50 for aquatic plants).
2.10.1.3 Integration of Exposure and Effects
57
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Risk characterization is the integration of exposure and ecological effects characterization to
determine the potential ecological risk from agricultural and non-agricultural uses of
esfenvalerate, and the likelihood of direct and indirect effects to CRLF in aquatic and terrestrial
habitats. The exposure and toxicity effects data are integrated in order to evaluate the risks of
adverse ecological effects on non-target species. For the assessment of esfenvalerate risks, the
risk quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are
divided by acute and chronic toxicity values. The resulting RQs are then compared to the
Agency's levels of concern (LOCs) (USEPA, 2004) (see APPENDIX L).
For this endangered species assessment, as discussed in Section 2.1, listed species LOCs are used
for comparing RQ values for acute and chronic exposures of esfenvalerate directly to the CRLF.
If estimated exposures directly to the CRLF of esfenvalerate resulting from a particular use are
sufficient to exceed the listed species LOC, then the effects determination for that use is "may
affect". When considering indirect effects to the CRLF due to effects to animal prey (aquatic
and terrestrial invertebrates, fish, frogs, and mice), the listed species LOCs are also used. If
estimated exposures to CRLF prey of esfenvalerate resulting from a particular use are sufficient
to exceed the listed species LOC, then the effects determination for that use is a "may affect." If
the RQ being considered also exceeds the non-listed species acute risk LOC, then the effects
determination is a LAA. If the acute RQ is between the listed species LOC and the non-listed
acute risk species LOC, then further lines of evidence {i.e. probability of individual effects,
species sensitivity distributions) are considered in distinguishing between a determination of
NLAA and a LAA. When considering indirect effects to the CRLF due to effects to algae as
dietary items or plants as habitat, the non-listed species LOC for plants is used because the
CRLF does not have an obligate relationship with any particular aquatic and/or terrestrial plant.
If the RQ being considered for a particular use exceeds the non-listed species LOC for plants, the
effects determination is "may affect." Further information on LOCs is provided in APPENDIX
L.
2.10.1.4 Data Gaps
Guideline studies are not available to provide estimates of esfenvalerate toxicity to aquatic plants
or terrestrial plants. No studies are available for determining the chronic toxicity of
esfenvalerate for birds (surrogate for terrestrial-phase amphibians). Although some information
on plants is available from the ECOTOX open literature (see Section 4.0), no further information
on esfenvalerate was found for birds.
Environmental fate data gaps exist for aerobic aquatic metabolism and anaerobic aquatic
metabolism, resulting in uncertainty in the assessment of the stability of esfenvalerate in aquatic
environments. In the absence of data, the Agency used results of soil metabolism studies to
estimate aquatic metabolism rates for aquatic exposure modeling. The aerobic aquatic
metabolism half-life, reflective of the persistence of esfenvalerate in the water column, was
assumed to be twice that of the aerobic soil metabolism half life. The anaerobic aquatic
metabolism half-life, reflective of persistence in the sediment, was assumed to be twice that of
the anaerobic soil metabolism half-life.
58
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While only a single guideline study existed for both aerobic and anaerobic soil metabolism, open
literature (Laskowski, 2002; Kelley, 2007) provided a range of half-lives for these routes of
degradation.
Only a single terrestrial field dissipation study, from 1990-1992, is available to assess the
dissipation of esfenvalerate under field conditions. This limits the degree to which the Agency is
able to characterize the combined interaction of multiple routes of dissipation in the field.
Limited information is available on the fate and transport of the four stereoisomers for
esfenvalerate. In the absence of such information, the Agency assumed that all four isomers
would behave similarly in the environment. All degradation half-lives were based on the
breakdown of the molecule rather than any isomerization that might occur in the environment.
59
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3.0 Exposure Assessment
Exposure is the contact or co-occurrence between a stressor (esfenvalerate) and a receptor (the
CRLF and the habitat upon which it depends). The objective of exposure assessment is to
describe exposure in terms of intensity, space, and time in units that can be combined with the
effects assessment (USEPA 1998) presented in section 4.0.
3.1 Label Application Rates and Intervals
Esfenvalerate labels may be categorized into two types: labels for manufacturing uses
(including technical grade esfenvalerate and its formulated products) and end-use products.
While technical products, which contain esfenvalerate of high purity, are not used directly in
the environment, they are used to make formulated products, which can be applied in specific
areas to control insects. The formulated product labels legally limit esfenvalerate's potential
use to only those sites that are specified on the labels. Each use will potentially provide a
different exposure of CRLF to esfenvalerate in terms of intensity, space, and time.
EFED uses models to estimate the intensity and duration of exposure of organisms to
chemical concentrations in the environment that are appropriate for locations at which the
exposure of esfenvalerate and/or its degradates will co-occur with the CRLF. Uses that
produce similar exposures (in terms of intensity, space, and time) are grouped together and
evaluated as a single exposure scenario because it would be unwieldy and impractical to
evaluate each individual esfenvalerate use. In this way, the large number of esfenvalerate
uses that vary greatly in terms of potential exposure can be grouped into a more manageable
number of exposure scenario groups that relatively accurately reflect the exposure expected
from each of the label-permitted esfenvalerate uses.
The purpose of the exposure assessment is to determine if the currently permitted label uses
will harm the CRLF, so scenarios for each use are developed using assumptions expected to
result in the highest exposures. However, as shown in section 2.4.4, the paucity of
information given on many esfenvalerate labels regarding the time of year when
esfenvalerate can be applied, the number of applications per year or crop-cycle, and the
minimum time until additional esfenvalerate treatments could be applied required that
assumptions be made in the design of these scenarios.
Maximum application rates were used in each scenario in order to ensure that scenarios were
conservative (protective of CRLF), at the same time they also represent the legal limit. For
agricultural uses and the forest use, it was assumed the maximum application rate would be
applied by ground or aerial application methods. When application intervals were not
specified, an application interval of seven days was assumed because this was the lowest
application interval provided on the labels. Application date was determined as described in
Section 3.2.2.3 Application Information. When the CDPR PUR usage data indicated more
than one start date, the application interval was also adjusted to model two start dates (see
almond scenarios). Non-agricultural uses often have application rates when converted to lbs
ai per acre that are much higher than the corresponding agricultural uses, but are applied to
much smaller areas. The maximum home and garden rates from each crop/site were
60
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evaluated collectively, using scenarios developed for ground application to residential areas,
right of ways, impervious surfaces, and lawns. Application dates for non-agricultural uses
were assumed to begin on April 1st. As some labels allow for many repeated applications,
some applications may occur outside the crop window of a particular scenario. AgDRIFT
was used to estimate the spray drift fraction with the buffers specified on the label.
Currently registered agricultural and non-agricultural uses of esfenvalerate within California
are discussed in Section 2.4. The uses being assessed using RQ methods are summarized in
Table 3-1.
Table 3-1. Esfenvalerate Uses, Scenarios, and Application Information for Estimating
Aquatic Environmental Concentrations.12
Scenario: Uses
Represented By
Scenario
Maximum
Single
Application
Rate (kg
ai/hectare)
Application
Date (Day-
Month)
Number of
Applications
Per Year3
Application Interval (Days)
CA almond WirrigSTD:
Almond, Filbert, Pecan,
Walnut
0.11
1-Jan
2
7
0.11
1-Jan and 1-July
2
NA
0.08
1-Jan and 1-July
4
7, 1 application after 1-Jan and
1-July
CAColeCropRLF:
Broccoli, Chinese
Broccoli, Cabbage,
Chinese Cabbage,
Cauliflower, Collards,
Kohlrabi, Mustard
0.06
1-May
24
7
0.06
1-May
12
7
CAcornOP: Corn
(unspecified), Field
Corn, Pop Corn, Sweet
Corn, Sunflower
0.06
1-Apr
20
7
0.06
1-Apr
5
7
NA7
CAcornOP: At Plant4'5
Applications to Corn
(unspecified), Field
Corn, Pop Corn, Sweet
Corn, Sunflower
0.11
1-Apr
1
C AcottonWirrigSTD:
Cotton
0.06
1-Sep
10
7
CAfruitWirrigSTD:
Apple, Apricot, Cherry,
Kiwi, Nectarine, Peach,
Pear, Plum, Prune
0.08
1-Jan
7
7
0.08
1-Jan and 1-June
9
7, 5 applications after 1-Jan
and 2 applications after 1-June
0.08
1-Mar and 1-
Nov
7
7, 4 applications after 1-Mar
and 2 applications (0.11
application rate) after 1-Nov
CAlettuceSTD: Head
Lettuce
0.06
1-Mar and 17-
Aug
14
7, 7 applications after 1-Mar
and 5 applications after 17-
Aug
CAMelonsRLF:
Cucumber, Eggplant,
Melons, Cantaloupe,
0.06
1-Apr
7
7
0.06
1-Apr
5
7
61
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Maximum
Scenario: Uses
Represented By
Scenario
Single
Application
Rate (kg
ai/hectare)
Application
Date (Day-
Month)
Number of
Applications
Per Year3
Application Interval (Days)
Honeydew, Musk
Melon, Watermelon,
Pumpkin, Squash (all or
unspecified), Summer
Squash, Winter Squash
C AonionWirrigSTD:
Radish
0.06
1-Apr
7
7
CAPotatoRLF:
0.06
1-Mar
10
7
White/Irish Potato,
Turnip
0.06
1-Mar
7
7
CARowCropRLF:
Artichoke, Dried Type
Beans, Succulent (Snap)
Beans, Carrot, Lentils,
0.06
1-Jun
3
7
Peas (Unspecified),
Dried-Type Peas,
Pepper
CAsugarbeetW irrigOP:
At Plant4'5 Application
to Sugarbeet
0.11
1-Sep
1
NA
0.11
1-Sep
1
NA
CAsugarbeetW irrigOP:
Sugarbeet
0.06
1-Sep
3
7
C AtomatoW irrigSTD:
Tomato
0.06
1-Jul
10
7
CAresidentialRLF: Non
Crop Land
0.06
1-Apr
10
7
C ArightofwayRLF:
Non Cropland
0.06
1-Apr
10
7
CAForestryRLF:
Christmas Tree
0.06
1-Mar
25s
7
Plantings, Conifer
Plantations, Orchards,
Forest Tree Nurseries
0.06
1-Jul
25s
7
CAnurserySTD:
Christmas Tree
0.06
1-Mar
25s
7
Plantings, Conifer
Plantations, Orchards,
Forest Tree Nurseries,
0.06
1-Jul
25s
7
and Forests
CAresidentialRLF:
Non-agricultural Uses6
0.22
1-Apr
1
NA
0.22
1-Apr
2
7
0.22
1-Apr
3
7
CAturfRLF: Lawns and
Turf Grass
0.22
1-Apr
3
7
C ArightofwayRLF:
0.22
1-Apr
3
7
Non-agricultural Uses
0.22
1-Apr
1
NA
62
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Scenario: Uses
Represented By
Scenario
Maximum
Single
Application
Rate (kg
ai/hectare)
Application
Date (Day-
Month)
Number of
Applications
Per Year3
Application Interval (Days)
C AlmperviousRLF:
Non-agricultural Uses
0.22
1-Apr
1
NA
1 Uses assessed based on memorandum from RD [September 7, 2007] confirming that the "list is accurate with
respect to products and use patterns currently registered containing" esfenvalerate. As some labels allow for many
repeated applications, some applications may occur outside the crop window of a particular scenario.
2 Did not include sugarcane, sorghum, and peanuts in the table because the CDPR PUR usage data indicates that less
than one pound of ai was applied to each of these sites and they do not fit within an already established scenario.
Also, esfenvalerate is restricted from use on sorghum on the Dupont Asana Label XL (EPA Registration Number
352-515).
3 Maximum applications per year were calculated by multiplying the maximum season rate by the maximum number
of seasons and dividing by the maximum single application rate. The values used in calculations are reported in
Table 2-3 and Table 2-4. When different maximum application rates were provided for a season and when dormant,
each season rate was divided by the maximum single application rate and added to arrive at the maximum number of
applications per year.
4 Assumed that when applied at plant that esfenvalerate was only applied once per season. Page four of the Dupont
Asana Label excludes CA for use of esfenvalerate at plant for corn to control black cutworm. However, page five
also discusses at plant usage on corn and does not exclude use in CA.
5 At plant applications and non-agricultural applications were assumed to be applied via ground application. In
these PRZM scenarios input parameters for ground applications are set to CAM =1, application efficiency = 0.99,
and fraction spray drift was determined using AgDRIFT. For aerial applications, input parameters were set to
CAM=2, application efficiency=0.95, and fraction spray drift was determined using AgDRIFT.
6 Assumed rate provided for lawns for all non-agricultural uses because many labels did not specify a maximum
application rate per area and the lawn use rate was the highest for the non-agricultural uses. These PRZM scenarios
are assumed to cover all non-agricultural uses. The use rate and use areas are similar for these uses.
7 NA stands for not applicable.
8 Thirty-two applications are actually possible with the maximum seasonal rate for tree and forest uses. However,
PRZM would not run with the 32 applications input value.
3.2 Aquatic Exposure Assessment
3.2.1 Modeling Approach
The EECs (Environmental Effects Concentrations) were calculated using the EPA Tier II PRZM
(Pesticide Root Zone Model) and EXAMS (Exposure Analysis Modeling System) with the
EFED Standard Pond environment, PRZM and EXAMS. PRZM is used to simulate pesticide
transport as a result of runoff and erosion from an agricultural field, and EXAMS estimates
environmental fate and transport of pesticides in surface water.
The most recent PRZM/EXAMS linkage program (PE5, PE Version 5, dated Nov. 15, 2006) was
used for all surface water simulations. Linked crop-specific scenarios and meteorological data
were used to estimate exposure resulting from use on crops and turf.
Aquatic exposures are quantitatively estimated for all assessed uses using scenarios that
represent high exposure sites for esfenvalerate use. Each of these sites represents a 10 hectare
field that drains into a 1-hectare pond that is 2 meters deep and has no outlet. Exposure
63
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estimates generated using the standard pond are intended to represent a wide variety of
vulnerable water bodies that occur at the top of watersheds including prairie pot holes, playa
lakes, wetlands, vernal pools, man-made and natural ponds, and intermittent and first-order
streams. As a group, there are factors that make these water bodies more or less vulnerable than
the standard surrogate pond. Static water bodies that have larger ratios of drainage area to water
body volume would be expected to have higher peak EECs than the standard pond. These water
bodies will be either shallower or have large drainage areas (or both). Shallow water bodies tend
to have limited additional storage capacity, and thus, tend to overflow and carry pesticide in the
discharge whereas the standard pond has no discharge. As watershed size increases beyond 10
hectares, at some point, it becomes unlikely that the entire watershed is planted to a single crop,
which is all treated with the pesticide. Headwater streams can also have peak concentrations
higher than the standard pond, but they tend to persist for only short periods of time and are then
carried downstream.
Esfenvalerate labels include a number of non-agricultural uses (Table 2-4), including
applications around buildings, structures, and equipment in residential, commercial, and
industrial areas; applications to lawns, grass, recreational areas, and uncultivated lands; and
applications to forest trees. These uses are represented by the residential, turf, rights-of-way,
impervious surface, and forestry scenarios listed in Table 3-1.
Residential and rights-of-way (ROW) scenarios were developed specifically for the San
Francisco Bay region using the conceptual approach developed for the Barton Springs
salamander atrazine endangered species risk assessment (U.S. EPA, 2006). The San Francisco
area was selected to be representative of urbanized areas with CRLF habitat present in the
general vicinity. The conceptual model for both scenarios integrates simultaneous modeling of
the individual use scenario with an impervious scenario. This approach assumes that no
watershed is completely covered by either the Vi acre lot (the basis for the residential scenario) or
undeveloped land (the basis for the ROW scenario) for residential and ROW use patterns;
therefore, differential amounts of runoff will occur within the watershed. The impervious
scenario was developed to represent the paved areas within a watershed not including roads,
parking lots, sidewalks, and buildings outside the Vi acre lot (the ]A acre lot scenario accounts for
impervious surfaces such as buildings within the represented area). By modeling a separate
scenario for impervious surfaces, it is also possible to estimate that amount of exposure that
could occur when the pesticide is over sprayed onto this surface. In previous endangered species
risk assessments, the amount of modeled overspray was assumed to be 1% of the labeled
application rate. Further details on how this value was derived and characterization of
alternative assumptions are provided in the Barton Springs salamander endangered species risk
assessment for atrazine (U.S. EPA, 2006).
In general, the majority of occupied areas (including core areas, designated critical habitat, and
occurrence data from CNDDB, which are further defined in Section 2.5) are located in areas
where the percentage of impervious surface is less than 20%. However, a few selected areas
with higher percentages of impervious surface (e.g., San Francisco Bay region) were evaluated to
determine a representative value for residential settings. The conceptual model for the ROW
scenario assumes that the watershed is represented by equal portions of impervious and pervious
surface (50%). Based on geospatial data, it is evident that the occupied areas with the highest
64
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percentage of impervious cover are urban areas outside the occupied areas, and, in general, the
occupied areas have impervious surface of less than 50%. Therefore, for purposes of modeling,
it is assumed that a representative percentage of impervious cover is 50%. In general, as the
percentage of impervious surface increases, the overall exposure resulting from applications to
the pervious surface decreases because less mass is applied within the watershed. Additional
information on the impact of this assumption has been previously characterized in the Barton
Springs salamander endangered species risk assessment for atrazine (U.S. EPA, 2006).
3.2.2 Model Inputs
The appropriate PRZM and EXAMS input parameters for esfenvalerate were selected from the
environmental fate data submitted by the registrant and in accordance with US EPA-OPP EFED
water model parameter selection guidelines, Guidance for Selecting Input Parameters in
Modeling the Environmental Fate and Transport of Pesticides, Version II, February 28, 2002.
Input parameters can be grouped by physico-chemical properties and environmental fate data,
application information, and scenarios.
3.2.2.1 Physico-chemical Properties and Environmental Fate
Esfenvalerate environmental fate data used for generating model parameters is listed in Table 2-1
and Table 2-2. The input parameters for PRZM and EXAMS are in Table 3-2.
Table 3-2. Summary of PRZM/EZAMS Environmental Fate Data Used for Aquatic
Exposure Inputs for Esfenvalerate Endangered Species Assessment for the CRLF.1'2
Fate Property
Value
MRID, Author Year(or
source)
Molecular Weight
419.9 g/mol
Kelley 2007
Henry's constant
1.4 x 10"12 atm-m3/mol
Laskowski 2002
Vapor Pressure
4.5 x 10"7 torr
46725304, Comb 2002
Solubility in Water
0.006 mg/L3
Laskowski 2002
Photolysis in Water
9 days
40443801, Stevenson 1987
Aerobic Soil Metabolism
138 days4
EFED Guidance2
Hydrolysis
Stable
409999303, Lee 1989
Aerobic Aquatic Metabolism (water
column)
Anaerobic Aquatic Metabolism
(benthic)
276 days5
462 days6
EFED Guidance2
EFED Guidance2
Koc
251,717 mL/g
EFED Guidance2
Application rate and frequency
See Table 3-1
EFED Guidance2
65
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Fate Property
Value
MRID, Author Year(or
source)
Application intervals
Chemical Application Method (CAM)
Application Efficiency
Spray Drift Fraction1
See Table 3-1
1 for ground applications
2 for aerial applications
0.99 for ground applications
0.95 for aerial applications
0.0071 for ground applications
0.0625 for aerial applications
EFED Guidance2
EFED Guidance2
EFED Guidance2
EFED Guidance2
1 The spray drift fractions were estimated using AgDRIFT and the buffers specified on labels. For aerial
applications, AgDRIFT values were set to very fine to fine drop size and a buffer of 450 feet. For ground
applications, AgDRIFT values were set to fine to medium drop size, high boom, and a buffer of 25 feet.
2 Inputs determined in accordance with EFED "Guidance for Chemistry and Management Practice Input
Parameters for Use in Modeling the Environmental Fate and Transport of Pesticides " dated February 28, 2002.
3 Three water solubility values were reported for esfenvalerate. The value for the guideline study submitted was not
specific enough to use (<0.01 mg/L) and the other values were very similar (0.002 and 0.006 mg/L) (see Table 2-1).
As the two values were very similar, the choice of the value would not have a significant affect on the modeling
results.
4 The aerobic soil metabolism half-life value is the 90th upper confidence bound on the mean metabolism half-life
using the equation in EFED Guidance and the values in APPENDIX J.
5 The aerobic aquatic metabolism half-life was estimated by multiplying the aerobic soil metabolism half-life by
two.
6 Assumed two times the aerobic soil metabolism half-life of 23 ldays because the compound is hydrolytically
stable and no aerobic or anaerobic aquatic metabolism data was available. As only one anaerobic soil metabolism
value was available, the measured value (77 days) was multiplied by three.
3.2.2.2 PRZM Scenarios
EPA used PRZM scenarios specific to California, representing a variety of crop and non-
agricultural scenarios. Each scenario is intended to represent a high-end exposure setting for a
particular crop. Each scenario location is selected based on various factors. Once a location is
selected, a scenario is developed using locally specific soil, climatic, and agronomic data. Each
PRZM scenario is assigned a specific climatic weather station providing 30 years of daily
weather values, see APPENDIX B for the station chosen for each scenario. Table 3-3
summarizes the PRZM scenario name and location. Residential, right-of-ways, and impervious
surface scenarios were processed further to estimate exposures when a percentage of a surface is
impervious and a percentage is pervious. The method used is described in APPENDIX K.
Treatment of 100% of an impervious surface is not expected to occur. However, these results
were included, as the PRZM results are used to estimate EECs and they represent exposure that
could occur when the pesticide is over sprayed onto an impervious surface.
66
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Table 3-3. PRZM/EXAMS Scenarios Used to Estimate Concentrations of Esfenvalerate in
the Aquatic Environment.1
Tier 2 Modeling Scenario
Location Modeled
CAalmond WirrigSTD2
San Joaquin County
CAColeCropRLF
Monterey County
CAcornOP
Stanislaus and Jan Joaquin Counties
CAcottonWirrigSTD2
Fresno County
CAfruitWirrigSTD2
Fresno County
CAlettucesSTD
Monterey County
CAMelonsRLF
Fresno, Merced, Kern, and Kings Counties
CAonionWirrigSTD2
Kern County
CAPotatoRLF
Kern County
CARowCropRLF
Kern, Monterey, San Luis Obispo, Santa Barbara, and Ventura Counties
C AsugarbeetW irrigOP2
Central Valley
C AtomatoW irrigSTD2
San Joaquin County
CAresidentialRLF
San Francisco
CArightof wayRLF
Central/ coastal CA
CAForestryRLF
Trinity, Shasta, Modoc, and Humboldt Counties
CAnurserySTD
San Diego
CAturfRLF
Central / northern CA
CAImperviousRFL
San Francisco
1 Counties for the different scenarios were taken from CA_PRZM_scenarios_surrogates.xls.
2 Assumed the scenarios that included data on irrigation were located in the same area as the associated STD
scenario, e.g., assumed that CAalomondSTD and CAalmondWirrigSTD, used the same location assumptions.
3.2.2.3 Application Information
Crop-specific management practices for all of the assessed uses of esfenvalerate were used for
modeling, including application rates, number of applications per year, application intervals, and
the first application date for each crop. The date of first application was developed based on
several sources of information including data provided by BEAD, a summary of individual
applications from the CDPR PUR data, and Crop Profiles maintained by the USD A. A sample
of the CDPR PUR data for 2005 used to determine the application date is provided in Figure 3-1,
with all figures provided in APPENDIX G. The amount of esfenvalerate applied by month to
almonds was used to pick January 1st and July 1st application dates for the tree nut scenarios.
67
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m
"O
o
£
o
3
CM
O
c
a.
0)
"O
U)
0)
CB
i_
a.
0)
Q.
>
<
<
5000
4000
3000
2000
1000
n
n
n
Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Application Month
Figure 3-1. Total Pounds of Esfenvalerate Applied to Almonds by
Month in 2005 based on CDPR PUR data.
More detail on the crop profiles and the previous assessments may be found at:
http://pestdata.ncsu.edu/cropprofiles/cropprofiles.cfm. All other application information used to
estimate concentrations in the aquatic environment is available in Table 3-1.
3.2.3
Results
The aquatic EECs for the various scenarios and application practices are listed in Table 3-4. The
output from PRZM-EXAMS is provided in APPENDIX B. Peak water column concentrations
for the agricultural applications ranged from 0.02 |j,g/L to 1.11 |~ig/L. Peak water column
concentrations from non-agricultural uses were higher and ranged from 0.05 |ig/L to 6.47 |ig/L.
The highest peak exposure predicted was for a scenario that assumed that the entire
watershed/application area was impervious. Such conditions (100% impervious surface) are not
expected to occur, even in a densely urban area. More accurate EECs, Residential Non-
Agricultural Uses with Impervious Surfaces and Right-of-Way Non-Agricultural Uses with
Impervious Surfaces, still have high peak EECs (~3 |ig/L). The next highest exposures were
predicted from the forestry and nursery scenarios, the uses with the highest number of
applications. Pore water concentrations were relatively constant over time, e.g., peak, 21 day,
and 60 day concentrations were all very similar and ranged from 0.001 - 0.241 |ig/L.
3.2.4 Existing Monitoring Data
The USGS NAWQA data warehouse27 included no monitoring results for esfenvalerate. While
the pesticide was included in earlier analytical methods, poor recoveries in the methods led to
http://infotrek.er.usgs.gov/traverse/f?p=NAWQA:HOME:543723453545295
68
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both its removal from the analytical method and deletion of all historical data in 1997 (Foreman
and Gilliom, 1997).
Esfenvalerate was included in surface water and sediment monitoring data obtained from the
California Department of Pesticide Regulation28. Esfenvalerate was detected in 3 of 365 surface
water samples (0.8% detections) where the limits of quantification ranged from 0.02 to 0.05
|ig/L. The detections - 0.06, 0.14, and 0.17 |ig/L - all occurred in Stanislaus County in 2003.
The two highest detections occurred in tributaries of the San Joaquin River while the lowest
detection was found in an irrigation distribution drain. Esfenvalerate was also detected in 21 out
of 259 sediment samples (8% detections), with limits of quantification from 0.001 to 0.01 (ig/g
(ppm). The detections, ranging from 0.002 to 0.07 ng/g, or 20 to 70 ng/g (ppb), were reported in
Imperial (2 detects), Monterey (5 detects), Placer (5 detects), and Stanislaus (9 detects) counties
between 2003 and 2005. Because these samples were not specifically targeted to esfenvalerate
use areas and were not collected at sites similar to the standard EXAMS pond (which is designed
to present a high EEC scenario), these detections are not expected to be comparable to
PRZM/EXAMS EECs. However, any agreement/disagreement can aid in characterizing the
uncertainty of the PRZM/EXAMS esfenvalerate EECs.
Weston et al. (2004) evaluated sediment samples from the Central Valley of California, with a
focus on the pyrethroid insecticides. Esfenvalerate was detected in 32% of 70 sediment samples
collected from 10 counties in the Central Valley, with the highest detections ranging from 11 to
30 ng/g (0.01 to 0.03 ppb) in three sampled creeks and sloughs and from 10 to 28 ng/g (0.01 to
0.028 ppb) in three irrigation canals (Weston et al., 2004).
28 http://www.cdpr.ca. gov/docs/sw/surfdata.htm
69
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Table 3-4. Aquatic EECs (jig/L) for Esfenvalerate Uses in California.1
Scenario: Uses
Represented By
Scenario
Maximum Single
App. Rate (kg
ai/hectare)
App. Date
(Day-
Month)
Number
of App.
App. Interval
(Days)
App.
Method
Estimated Environmental Concentrations
(EECs) in u.g/L
Water Column
Pore Water
Peak
21
Day
60 Day
Peak
21
Day
60
Day
CA almond WirrigSTD:
Almond, Filbert, Pecan,
Walnut
0.11
1-Jan
2
7
Aerial
0.240
0.047
0.033
0.010
0.009
0.009
0.11
1-Jan
2
7
Ground
0.054
0.011
0.009
0.003
0.003
0.003
0.11
1-Jan
2
180
Aerial
0.239
0.035
0.028
0.009
0.009
0.009
0.08
1-Jan
4
7, 170, 7
Aerial
0.192
0.050
0.041
0.013
0.013
0.013
CAColeCropRLF:
Broccoli, Chinese
Broccoli, Cabbage,
Chinese Cabbage,
Cauliflower, Collards,
Kohlrabi, Mustard
0.06
1-May
24
7
Aerial
0.626
0.288
0.279
0.099
0.098
0.097
0.06
1-May
24
7
Ground
0.538
0.171
0.162
0.055
0.055
0.054
0.06
1-May
12
7
Aerial
0.261
0.141
0.139
0.045
0.045
0.044
0.06
1-May
12
7
Ground
0.214
0.069
0.066
0.022
0.022
0.022
CAcornOP: Corn
(unspecified), Field
Corn, Pop Corn, Sweet
Corn, Sunflower
0.06
1-Apr
20
7
Aerial
1.112
0.279
0.264
0.088
0.087
0.086
0.06
1-Apr
20
7
Ground
0.868
0.169
0.148
0.049
0.049
0.049
0.06
1-Apr
5
7
Aerial
0.201
0.069
0.061
0.019
0.019
0.019
CAcornOP: At Plant
Applications to Corn
(unspecified), Field
Corn, Pop Corn, Sweet
Corn, Sunflower
0.11
1-Apr
1
NA2
Ground
0.060
0.013
0.011
0.004
0.004
0.004
CAcotton WirrigSTD:
Cotton
0.06
1-Sep
10
7
Aerial
0.195
0.080
0.077
0.023
0.023
0.023
0.06
1-Sep
10
7
Ground
0.107
0.029
0.026
0.008
0.008
0.008
CAfruitWirrigSTD:
Apple, Apricot, Cherry,
Peach, Pear, Plum,
Prune, Nectarine
0.08
1-Jan
9
7
Aerial
0.232
0.084
0.079
0.023
0.023
0.022
0.08
1-Jan
9
7
Ground
0.065
0.014
0.013
0.004
0.004
0.004
70
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Scenario: Uses
Represented By
Scenario
Maximum Single
App. Rate (kg
ai/hectare)
App. Date
(Day-
Month)
Number
of App.
App. Interval
(Days)
App.
Method
Estimated Environmental Concentrations
(EECs) in ng/L
Water Column
Pore Water
Peak
21
Day
60 Day
Peak
21
Day
60
Day
0.08
1-Jan
9
7,7,7,7,7,115,7,7
Aerial
0.220
0.081
0.072
0.021
0.021
0.021
0.08
1-Mar
7
7,7,7,7,210,7 (last 2
applications at 0.11)
Aerial
0.259
0.073
0.063
0.019
0.019
0.018
0.08
1-Mar
7
7,7,7,7,210,7 (last 2
applications at 0.11)
Ground
0.034
0.010
0.010
0.003
0.003
0.003
CAlettuceSTD: Head
Lettuce
0.06
1-Mar
14
7,7,7,7,7,7,7,120,7,7
,7,7,7
Aerial
0.883
0.260
0.250
0.085
0.085
0.084
0.06
1-Mar
14
7,7,7,7,7,7,7,120,7,7
,7,7,7
Ground
0.847
0.189
0.171
0.059
0.059
0.059
CAMelonsRLF:
Cucumber, Eggplant,
Melons, Cantaloupe,
Honeydew, Musk
Melon, Watermelon,
Pumpkin, Squash (all or
unspecified), Summer
Squash, Winter Squash
0.06
1-Apr
7
7
Aerial
0.152
0.051
0.046
0.013
0.013
0.012
0.06
1-Apr
5
7
Aerial
0.142
0.041
0.033
0.009
0.009
0.009
0.06
1-Apr
7
7
Ground
0.017
0.006
0.006
0.002
0.002
0.002
CAonion WirrigSTD:
Radish
0.06
1-Apr
7
7
Aerial
0.152
0.050
0.045
0.012
0.012
0.012
0.06
1-Apr
7
7
Ground
0.040
0.009
0.008
0.003
0.003
0.003
CAPotatoRLF:
White/Irish Potato,
Turnip
0.06
1-Mar
10
7
Aerial
0.165
0.063
0.060
0.017
0.017
0.017
0.06
1-Mar
7
7
Aerial
0.151
0.049
0.044
0.012
0.012
0.012
0.06
1-Mar
10
7
Ground
0.041
0.010
0.010
0.003
0.003
0.003
CARowCropRLF:
Artichoke, Dried Type
Beans, Succulent (Snap)
Beans, Carrot, Lentils,
0.06
1-Jun
3
7
Aerial
0.144
0.043
0.033
0.010
0.010
0.010
71
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Scenario: Uses
Represented By
Scenario
Peas (Unspecified),
Dried-Type Peas,
Pepper
Maximum Single
App. Rate (kg
ai/hectare)
App. Date
(Day-
Month)
Number
of App.
App. Interval
(Days)
App.
Method
Estimated Environmental Concentrations
(EECs) in ng/L
Water Column
Pore Water
Peak
21
Day
60 Day
Peak
21
Day
60
Day
0.06
1-Jun
3
7
Ground
0.046
0.012
0.011
0.004
0.004
0.004
CAsugarbeetW irrigOP:
At Plant Application to
Sugarbeet
0.11
1-Sep
1
NA
Ground
0.034
0.008
0.006
0.002
0.002
0.002
CAsugarbeet WirrigOP:
Sugarbeet
0.06
1-Sep
3
7
Aerial
0.137
0.036
0.026
0.008
0.008
0.007
0.06
1-Sep
3
7
Ground
0.057
0.013
0.011
0.004
0.003
0.003
C AtomatoW irrigSTD:
Tomato
0.06
1-Jul
10
7
Aerial
0.168
0.068
0.066
0.019
0.019
0.018
0.06
1-Jul
10
7
Ground
0.052
0.012
0.012
0.004
0.004
0.004
CAresidentialRLF: Non
Crop Land
0.06
1-Apr
10
7
Aerial
0.185
0.085
0.081
0.025
0.025
0.024
0.06
1-Apr
10
7
Ground
0.023
0.011
0.011
0.003
0.003
0.003
C ArightofwayRLF:
Non Cropland
0.06
1-Apr
10
7
Aerial
0.193
0.091
0.088
0.027
0.027
0.027
0.06
1-Apr
10
7
Ground
0.071
0.019
0.019
0.006
0.006
0.006
CAForestryRLF:
Christmas Tree
Plantings, Conifer
Plantations, Orchards,
Forest Tree Nurseries,
and Forests
0.06
1-Mar
25
7
Aerial
2.266
0.618
0.588
0.207
0.206
0.204
0.06
1-Jul
25
7
Aerial
2.562
0.740
0.706
0.245
0.244
0.241
0.06
1-Jul
25
7
Ground
2.083
0.506
0.473
0.168
0.167
0.165
CAnurserySTD:
Christmas Tree
Plantings, Conifer
Plantations, Orchards,
Forest Tree Nurseries,
0.06
1-Mar
25
7
Aerial
3.494
0.630
0.530
0.178
0.177
0.175
0.06
1-Jul
25
7
Aerial
3.862
0.780
0.649
0.216
0.215
0.212
72
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Scenario: Uses
Represented By
Scenario
and Forests
Maximum Single
App. Rate (kg
ai/hectare)
App. Date
(Day-
Month)
Number
of App.
App. Interval
(Days)
App.
Method
Estimated Environmental Concentrations
(EECs) in ng/L
Water Column
Pore Water
Peak
21
Day
60 Day
Peak
21
Day
60
Day
0.06
1-Jul
25
7
Ground
3.383
0.638
0.523
0.170
0.169
0.167
CAresidentialRLF:
Non-agricultural Uses3
0.22
1-Apr
1
NA
Ground
0.051
0.006
0.004
0.001
0.001
0.001
0.22
1-Apr
2
7
Ground
0.055
0.011
0.008
0.003
0.002
0.002
0.22
1-Apr
3
7
Ground
0.058
0.017
0.013
0.004
0.004
0.004
CAturfRLF: Lawns and
Turf Grass
0.22
1-Apr
3
7
Ground
0.060
0.018
0.014
0.004
0.004
0.004
C ArightofwayRLF:
Non-agricultural Uses3
0.22
1-Apr
3
7
Ground
0.080
0.025
0.021
0.007
0.007
0.007
0.22
1-Apr
1
NA
Ground
0.054
0.009
0.007
0.002
0.002
0.002
C AlmperviousRLF:
Non-agricultural Uses4'5
Residential Non-
Agricultural Uses with
Impervious Surfaces4
Right-of-Way Non-
Agricultural Uses with
Impervious Surfaces4
0.22
NA
NA
1-Apr
1-Apr
1-Apr
1
1
1
NA
NA
NA
Ground
Ground
Ground
6.463
3.183
3.185
0.568
0.347
0.348
0.347
0.0006
0.205
0.092
ND7
N
ND7
0.091
7
D N
ND7
»T
0.090
7
D
7
1 Application is abbreviated with App.
2 Not Applicable is abbreviated with NA.
3 The results from this scenario represent EECs in an area where the entire surface treated is pervious. Exposure was also estimated for residential and right of
way areas that also have a percentage of impervious surface present.
4 An entire impervious surface is not expected to be treated and some surfaces in residential and right-of-way uses will have impervious surfaces. The results
from the output from the impervious surface scenario were used as described in APPENDIX K to estimate EECs in residential and right of way scenarios that
have impervious surfaces.
5 This represents a high end exposure that is not expected to occur
6 A value of 0.000 indicates that the estimated EEC was less than 0.001.
7 Not determined is abbreviated with ND.
73
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3.3 Terrestrial Animal Exposure Assessment
T-REX (Version 1.3.1) is used to calculate dietary and dose-based EECs of esfenvalerate for the
CRLF and its potential prey (e.g. small mammals and terrestrial insects) inhabiting terrestrial
areas. EECs used to represent the CRLF are also used to represent exposure values for frogs that
serve as potential prey of CRLF adults. T-REX simulates a 1-year time period. For this
assessment, spray/granular applications of esfenvalerate are considered, as discussed below.
Terrestrial EECs for foliar formulations of esfenvalerate were derived for the uses summarized in
Table 3-5. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for
Esfenvalerate with T-REX. T-REX requires an estimate of the foliar dissipation half-life, which
can be obtained for many chemicals from Willis and McDowell (1987). There is no value
available for esfenvalerate, but this document does contain several estimates for fenvalerate,
which is closely related. EFED's policy is to use the 90% upper confidence limit if multiple
values are available. Based on the nine values available, the estimated half-life to be used is
12.3. An example output from T-REX is available in Appendix E. T-REX does not have the
capability of modeling multiple seasons as is possible for determining aquatic EECs. Therefore,
EECs were determined for terrestrial animals for only one season of application. This differs
from the aquatic exposure analysis, which did take multiple seasons per year into account.
Results of this analysis would impact chronic exposure estimates, possibly resulting in higher
chronic RQs. The impact of multiple growing seasons per year on this analysis is discussed in
the Risk Characterization section.
Table 3-5. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for
Esfenvalerate with T-REX.
I so (Application hum hod)
Application rate
Nil ill hoi' of
(lbs ;ii/.\)
Applications
Field Corn
0.05
1
Radish
0.05
2
Artichoke, Sugarbeet (broadcast), Peanuts
0.05
3
Collards, Mustard, Sunflower, Beans (Dried, Succulent), Lentils, Peas,
Sugarcane
0.05
4
Field Corn, Cucumber, Melons (all, Cantaloupe, Honeydew, Musk,
Water), Pumpkin, Squash (Unspecified, Summer, Winter), Turnip,
Sugarbeet (row application)
0.05
5
Kohlrabi, Eggplant, Potato (White, Irish), Pepper
0.05
7
Broccoli, Chinese broccoli, Cauliflower, Cabbage, Chinese Cabbage
0.05
8
Corn, Pop Corn, Sweet Corn, Carrot, Cotton, Tomato, Non-cropland
0.05
10
Forestry
0.05
25
Pecan
0.075
4
Apple, Pear, Kiwi, Lettuce (Head)
0.075
7
Apricot, Cherry, Nectarine, Peach, Plum, Prune
0.075
9
Kennels and housing areas
0.1
1
Almond, Filbert, Walnut
0.1
2
Buildings, Lawns and turf grass, Mosquito breeding areas
0.2
1
General Outdoor Surfaces
0.51
1
74
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T-REX is also used to calculate EECs for terrestrial insects exposed to esfenvalerate.
Esfenvalerate residues on small and large insects (units of a.i./g), calculated as dietary-based
EECs in T-REX, are used to bound an estimate of exposure to bees. These EECs are adjusted for
comparison to available acute contact toxicity data for bees exposed to esfenvalerate (in units of
|ig a.i./bee), by multiplying the EEC (in |ig a.i./g insect) by 0.128 g-bw/bee to get the adjusted
EEC in units of |ig a.i./bee. The EECs are later compared to the adjusted acute contact toxicity
data for bees in order to derive RQs.
For modeling purposes, exposures of the CRLF to esfenvalerate through contaminated food are
estimated using the EECs for a surrogate, the small bird (20 g), which consumes small insects.
Dietary-based and dose-based exposures of potential small mammalian prey are assessed using a
scenario of a small mammal (15 g) which consumes short grass (the dietary item that contains
the highest residues). Upper-bound Kenega nomogram values reported by T-REX for these two
organism types are used for derivation of EECs for the CRLF and its potential small mammalian
prey (Table 3-6) and its terrestrial insect prey (Table 3-7). Dietary-based EECs for small and
large insects reported by T-REX as well as the resulting adjusted EECs are available in Table
3-7. An example output from T-REX v. 1.3.1 is available in Appendix C.
Table 3-6.Upper-Bound Kenaga Nomogram EECs for Dietary- and Dose-based Exposures
of the CRLF and its Small Mammalian Prey to Esfenvalerate.
Use
EECs for CRLF
EECs for Prcv
(small mammals)
Dictarv-bascd
Dosc-bascd EEC
Dictarv-bascd
Dosc-bascd EEC
EEC (ppm)
(mjj/ks-bw)
EEC (ppm)
(m«/k«-b\v)
Field Corn
6.75
7.69
12.00
11.44
Radish
11.30
12.87
20.09
19.50
Artichoke, Sugarbeet
(broadcast), Peanuts
14.37
16.36
25.54
24.35
Collards, Mustard, Sunflower,
Beans (Dried, Succulent),
Lentils, Peas, Sugarcane
16.43
18.72
29.22
27.85
Field Corn, Cucumber,
Melons (all, Cantaloupe,
Honeydew, Musk, Water),
Pumpkin, Squash
(Unspecified, Summer,
Winter), Turnip, Sugarbeet
(row application)
17.83
20.30
31.69
30.22
Kohlrabi, Eggplant, Potato
(White, Irish), Pepper
19.40
22.09
34.49
32.88
Broccoli, Chinese broccoli,
Cauliflower, Cabbage,
Chinese Cabbage
19.83
22.58
35.25
33.60
Corn, Pop Corn, Sweet Corn,
Carrot, Cotton, Tomato, Non-
cropland
20.31
23.13
36.10
34.42
Forestry
20.71
23.58
36.81
35.10
Pecan
24.65
28.07
43.82
41.78
Apple, Pear, Kiwi, Lettuce
29.10
33.14
51.73
49.32
75
-------
I so
r.r.Cs lor cm.i-
r.r.Cs for i»iv\
(sin ;i II in ;i in in ills)
Dielan-based
Dose-based r.r.c
Dielan-based
Doso-hiisod r.r.c
I I.( (ppm)
()
I I.( (pi""*
(iii«i/k^-l»\\)
(Head)
Apricot, Cherry, Nectarine,
Peach, Plum, Prune
30.17
34.36
53.63
51.14
Kennels and housing areas
13.50
15.38
24.00
27.33
Almond, Filbert, Walnut
22.60
25.74
40.18
38.31
Buildings, Lawns and turf
grass, Mosquito breeding
areas
27.00
30.75
48.00
45.76
General Outdoor Surfaces
68.85
78.41
122.40
116.70
Table 3-7. EECs (ppm) for Indirect Effects to the Terrestrial-Phase CRLF via Effects to
Terrestrial Invertebrate Prey Items.
Small Insect
Small Insect
Large Insect
Large Insect
Use
Dictarv EEC
Adjusted EEC
Dictarv EEC
Adjusted EEC
(ppm)
(UK a.i./bee)
(ppm)
(jig a.i./bcc)
Field Corn
6.75
0.86
0.75
0.10
Radish
11.30
1.44
1.26
0.16
Artichoke, Sugarbeet (broadcast), Peanuts
14.37
1.84
1.60
0.20
Collards, Mustard, Sunflower, Beans
(Dried, Succulent), Lentils, Peas,
Sugarcane
16.43
2.10
1.83
0.23
Field Corn, Cucumber, Melons (all,
Cantaloupe, Honeydew, Musk, Water),
Pumpkin, Squash (Unspecified, Summer,
Winter), Turnip, Sugarbeet (row
application)
17.83
2.28
1.98
0.25
Kohlrabi, Eggplant, Potato (White, Irish),
Pepper
19.40
2.48
2.16
0.28
Broccoli, Chinese broccoli, Cauliflower,
Cabbage, Chinese Cabbage
19.83
2.54
2.20
0.28
Corn, Pop Corn, Sweet Corn, Carrot,
Cotton, Tomato, Non-cropland
20.31
2.60
2.26
0.29
Forestry
20.71
2.65
2.30
0.29
Pecan
24.65
3.16
2.74
0.35
Apple, Pear, Kiwi, Lettuce (Head)
29.10
3.72
3.23
0.41
Apricot, Cherry, Nectarine, Peach, Plum,
Prune
30.17
3.86
3.35
0.43
Kennels and housing areas
13.50
1.73
1.50
0.19
Almond, Filbert, Walnut
22.60
2.89
2.51
0.32
Buildings, Lawns and turf grass, Mosquito
breeding areas
27.00
3.46
3.00
0.38
General Outdoor Surfaces
68.85
8.81
7.65
0.98
3.4 Terrestrial Plant Exposure Assessment
Risk to terrestrial plants cannot be determined quantitatively due to lack of terrestrial plant
toxicity data.
76
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4.0 Effects Assessment
This assessment evaluates the potential for esfenvalerate to directly or indirectly affect the CRLF
and/or modify its designated critical habitat. As previously discussed in Section 2.8, assessment
endpoints for the CRLF include direct toxic effects on the survival, reproduction, and growth, as
well as indirect effects, such as reduction of the prey base or modification of its habitat. In
addition, potential modification of critical habitat is assessed by evaluating effects to the PCEs,
which are components of the critical habitat areas that provide essential life cycle needs of the
CRLF. Direct effects to the aquatic-phase of the CRLF are based on toxicity information for
freshwater fish, while terrestrial-phase effects are based on avian toxicity data, given that birds
are generally used as a surrogate for terrestrial-phase amphibians. Because the frog's prey items
and habitat requirements are dependent on the availability of freshwater fish and invertebrates,
small mammals, terrestrial invertebrates, and aquatic and terrestrial plants, toxicity information
for these taxa are also discussed. Toxicity data used to evaluate direct effects, indirect effects,
and modification to critical habitat in this risk assessment for esfenvalerate are summarized in
Table 4-1.
Information on the toxicity of esfenvalerate to selected taxa is characterized based on registrant-
submitted studies and a comprehensive review of the open literature on esfenvalerate (primarily
SS stereoisomer) and the sterioisomeric related compound fenvalerate (approximately equal
mixture of RR, RS, SR, and SS isomers). Esfenvalerate contains more of the insecticidally
active isomer; however, the more evenly isomeric mixture, fenvalerate, is more toxic than
esfenvalerate for some taxa. Ultimately, organisms exposed to esfenvalerate in water are
exposed to a mixture of isomers because esfenvalerate sterioisomerizes in water. Therefore,
fenvalerate toxicity endpoints that are more sensitive than that of esfenvalerate are used in this
assessment where applicable. Fenvalerate data are also used where data are lacking for
esfenvalerate.
Values used for each measurement endpoint identified in Table 2-8 are selected from these data.
Currently, no FIFRA data requirements exist for aquatic-phase or terrestrial-phase frogs and are
therefore not part of typical registrant submitted data packages. A summary of the available
ecotoxicity information; the selected individual, population, and community-level endpoints for
characterizing risks; and interpretation of the LOC, in terms of the probability of an individual
effect based on probit dose response relationship are provided in Sections 4.1 through 4.3.
Toxicity measurement endpoints are selected from data generated from guideline studies
submitted by the registrant, and from open literature studies that meet the criteria for inclusion
into the ECOTOX database maintained by EPA/Office of Research and Development (ORD)
(U.S. EPA, 2004). Open literature data presented in this assessment were obtained from a search
of the ECOTOX database (July 2007). Table 4-1 summarizes the most sensitive results for each
measurement endpoint, based on an evaluation of both the submitted studies and the open
literature, as previously discussed. A brief summary of submitted and open literature data
considered relevant to this ecological risk assessment is presented below. Additional
information is provided in APPENDIX D-F.
77
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In order to be included in the ECOTOX database, papers must meet the following minimum
criteria:
(1) the toxic effects are related to single chemical exposure;
(2) the toxic effects are on an aquatic or terrestrial plant or animal species;
(3) there is a biological effect on live, whole organisms;
(4) a concurrent environmental chemical concentration/dose or application rate is reported;
and
(5) there is an explicit duration of exposure.
Data that pass the ECOTOX screen are further evaluated along with the registrant-submitted
data, and may be incorporated qualitatively or quantitatively into this endangered species
assessment. In general, effects data in the open literature, matching measurement endpoints
listed in Table 2-8, that are more conservative than the registrant-submitted data and that are
found to be scientifically sound based on a review of the paper are used quantitatively. The
degree to which open literature data are used quantitatively or qualitatively is dependent on
whether the information is scientifically sound and whether it is quantitatively linked to the
assessment endpoints (e.g., maintenance of California Red-Legged Frog survival, reproduction,
and growth) identified in Table 2-8. For example, endpoints such as behavior modifications are
likely to be qualitatively evaluated, because quantitative relationships between degree and type
of behavior modifications and reduction in species survival, reproduction, and/or growth are
usually not available.
Citations of all open literature not considered as part of this assessment because they were either
rejected by the ECOTOX screen or accepted by ECOTOX but not used (e.g., the endpoint is less
sensitive and/or not appropriate for use in this assessment) are included in Appendices D-F.
Appendices D-F also includes a rationale for rejection of those studies that did not pass the
ECOTOX screen and those that were not evaluated as part of this endangered species risk
assessment.
Among the ECOTOX studies that were reviewed, none reported the necessary information or
were of sufficient quality to be used quantitatively. Many of these studies used fenvalerate as the
test material. As discussed above, fenvalerate is utilized when no data are available for
esfenvalerate, so information from these studies is qualitatively incorporated where appropriate.
Table 4-1. Summary of Esfenvalerate Toxicity Data Used to Assess Direct Effects, Indirect
Effects, and Adverse Modification to Critical Habitat for the CRLF.
Assessment
Endpoints
Measures of
Effect
Species
Toxicity Value
and Slope
(where
applicable)
Study
Classification
(selection basis)
Reference
Survival and
reproduction of
individuals and
communities of
Freshwater fish
acute 96-hr LC50
Rainbow trout
(Oncorhynchus
mykiss)
0.07 ppb ai
Slope = 7.0
(95% CI 3.2-
10.7)
Acceptable
(Most sensitive
value)
43358311
Baer 1994
78
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Assessment
Endpoints
Measures of
Effect
Species
Toxicity Value
and Slope
(where
applicable)
Study
Classification
(selection basis)
Reference
freshwater fish
Freshwater fish
early life-stage
NOAEC
estimated from
ACR
Rainbow trout
(0. mykiss)
0.035 ppb ai
N/A
(ACR estimate)
ACR approach
used see Section
4.1.2.2
Survival and
reproduction of
individuals and
communities of
freshwater
invertebrates
Freshwater
invertebrate
acute 48-hr EC50
Waterflea
(Daphnia
magna)
0.05 ppb ai
Slope not
available
Acceptable
(Most sensitive
value)
41891914
Baer 1991
Freshwater
invertebrate
NOAEC
estimated from
ACR
Water flea (D.
magna)
0.017 ppb ai
N/A
(ACR estimate)
ACR
approached used
see Section
4.1.3.2
Survival and
growth of
aquatic plants
Vascular and
nonvascular
aquatic plant
EC50 and
NOAEC
No studies available
Abundance (i.e.,
survival,
reproduction,
and growth) of
individuals and
populations of
birds
Avian (single
dose) acute oral
ld50
Northern
bobwhite
(Colinus
virginianus)
381 mgai/kg
Acceptable
(Only value
available)
41698401
Campbell et al.
1991
Avian subacute
5-day dietary
LC50
Mallard
(Anas
platyrhynchos)
4894 ppm ai
Acceptable
(Most sensitive
value)
41637802
Driscoll et al.
1990
Avian
reproduction
NOAEC
No studies available1
Abundance (i.e.,
survival,
reproduction,
and growth) of
individuals and
populations of
mammals
Mammalian
acute oral
(single dose)
LD50
Laboratory rat
(Rattus
norvegicus)
59.0 mg/kg
Slope not
reported
Acceptable
(Most sensitive
value)
46765601
Finlay, 2005
Mammalian
reproductive
NOAEL
Laboratory rat
(Rattus
norvegicus)
4.21 mg/kg/day
Acceptable
(Most sensitive
value)
43489001
Biegel 1994
Survival of
beneficial insect
populations
Honey bee acute
contact LD50
Honey bee
(Apis mellifera)
0.017 (ig/bee
Slope not
determined
Acceptable
(Only value
available)
41698402
Hoxter and
Smith 1990
Survival and
growth of
terrestrial plants
Seedling
emergence and
vegetative vigor
EC25 and
NOAEC
No studies available
1 A study is available that used fenvalerate instead of esfenvalerate and was not sufficient to produce a definitive
NOAEC. Therefore, potential risk using the value from this study (NOAEC <25 ppm) will be discussed
qualitatively, but contains too much uncertainty to be used quantitatively.
79
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4.1 Evaluation of Aquatic Ecotoxicity Studies
Data collected on freshwater fish and invertebrates are utilized in this risk assessment to estimate
direct effects to the aquatic-phase CRLF resulting from acute and chronic exposure, indirect
effects to the CRLF resulting from loss of prey and loss/disturbance of aquatic habitat and
modification of Critical Habitat PCEs. Toxicity endpoints available for this assessment and the
endpoints actually selected for quantitative assessment of direct and indirect effects to the CRLF
are summarized in the sections below.
4.1.1 Toxicity to Amphibians
Two toxicity studies with frogs are available from the ECOTOX database. Neither of these
studies provides an adequate estimate of toxicity that may be used; however they do provide
some information regarding the hazard of esfenvalerate to amphibians.
Johansson et al. (2006) tested the toxicity of esfenvalerate on tadpoles of the common frog (Rana
temporaria). Tadpoles of common frogs were exposed to 0.3, 1.3 and 5.0 ppb esfenvalerate for
72 hours in acute tests, wherein their mean dry weight, body length, and tail length were
measured along with survival. Esfenvalerate did not show any significant effects on size
parameters, indicating no effects on growth, nor was there any significant effect on survival. The
study cites an estimate of esfenvalerate toxicity to amphibians (LC50 = 7.3 ppb ai), which it uses
as a basis for setting the exposure levels for the study, although they provide no information as to
what species this value is for.
Materna et al. (1995) used tadpoles of three species of leopard frogs (Ranapipiens, Rana
sphenocephala, and Rana blairi) to test acute effects of esfenvalerate in the laboratory and in the
field. R. pipiens was exposed in the laboratory to concentrations of esfenvalerate at 0.8, 1.3, 2.2,
3.6, 6.0, and 10.0 ppb ai for 96 hours at 20°C, and behavioral effects, including convulsive and
spasmodic behavior, twitching, and twisting of the body and tail. The test levels were based on a
range-finding study in which mortality occurred at concentrations of 100 ppb ai and higher.
Since the goal of the study was to examine sublethal effects, the test concentrations were set
lower than this value. Additionally, the effects of temperature (18°C and 22°C) on behavior
were observed in tadpoles exposed to nominal concentrations of 0.0, 1.23, 1.76, 2.64, 5.07, 7.47,
and 11.47 ppb ai. In the field experiment, tadpoles of R. blairi and R. sphenocephala were
contained within enclosures treated with 0.0, 3.6, 6.0 and 10.0 ppb ai, and growth and behavioral
abnormalities were measured.
In the laboratory study, an EC50 of 4.85 ppb ai was determined based on behavioral effects.
Some mortality was observed at 2.2, 6.0, and 10.0 ppb ai. The EC50 at 18°C was 3.4 ppb ai and
was 6.14 ppb ai at 22°C based on tail-kink abnormalities. In the pond study, effects observed
were decreased activity, convulsions, tail kinking, and mortality. Mortality occurred in nearly a
dose-response fashion, but an LC50 could not be calculated due to extreme variability in the
measured concentrations. Mortality reached nearly 85% in the highest concentration in this
study, and occurred rapidly (within the 96-hour test period).
There was wide variation in the nominal and measured concentrations used in this study that
result in uncertainty in the results of these studies. Results are presented with nominal
80
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concentrations, but the actual concentrations varied. Concentrations decreased by up to 80% of
nominal in some of the laboratory tests. In the field test, the actual concentrations measured in
the test chambers ranged 35% to 206% of nominal, which could have been the result of
inadequate mixing within the test system.
Both of these studies provide information about toxicity to amphibians, and it appears that Rana
spp. may be less sensitive to esfenvalerate than the surrogate species (freshwater fish) used to
estimate risk. Therefore, although the results of these studies cannot be used quantitatively, they
provide evidence that the Agency's use of fish acute toxicity values result in a conservative
estimate of risk for the CRLF.
4.1.2 Toxicity to Freshwater Fish
No aquatic-phase amphibian studies are available for esfenvalerate. Therefore, toxicity studies
with freshwater fish are used to assess direct acute and chronic effects to the aquatic phase CRLF
as well as indirect acute and chronic effects to its food sources. Freshwater fish are considered to
be surrogates for the CRLF, and toxicity to each taxon is assumed to be comparable. Fish
toxicity studies for two freshwater species using the technical grade active ingredient (TGAI) are
required to establish the acute toxicity of esfenvalerate to fish. The preferred test species are
rainbow trout (a coldwater fish) and bluegill sunfish (a warm water fish); however, tests with
other species are also submitted.
4.1.2.1 Freshwater Fish: Acute Exposure (Mortality) Studies
One study with the esfenvalerate TGAI and five studies with formulated products are available
with which to estimate the hazard of esfenvalerate to the CRLF (Table 4-2). An additional study
with the TGAI on bluegill was available in the chemical file, but was not assigned a MRID and
has not been used in previous risk assessments. This study was found to be acceptable by the
EFED reviewer, and findings were similar to that of other studies listed below (96-hour LC50 =
0.26 ppb ai, with 98.8% test material purity). However, the history of this study is not known, so
it has not been included. Based on the studies presented, esfenvalerate is very highly toxic to
freshwater fish on an acute basis. Toxicity was determined to be the same for both bluegill and
trout in the TGAI studies. The most sensitive value comes from the study with the 44.4%
formulated product (MRID 43358311). MRID 41215201 is a study with the SS-isomer only, and
the test material did not contain the other three isomers found in esfenvalerate. However, since
the toxicity of the other formulated products appears to be comparable to that of the TGAI, the
toxicity value from MRID 43358311 (LC50 = 0.07 ppb ai) will be used to quantitatively estimate
risk to the CRLF and its freshwater fish food base.
Several studies with fenvalerate are available; however, none of these provided a more sensitive
estimate of toxicity than the studies listed below. LC50 values from acceptable or supplemental
studies using the TGAI range from 0.42 to 1.13 ppb ai. Formulated products were less toxic,
with LC50S ranging from 1.02 to 4.3 ppb ai.
81
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Table 4-2. Acute Toxicity of Esfenvalerate to Freshwater Fish.
Species
study type
%ai
96-hr LCS0
Toxicity
Category
Reference
(MRID, Author)
Study
Classification
Rainbow trout
(Oncorhynchus mykiss)
static
98.8
(TGAI)
0.26 ppb ai
(nominal)
Very Highly
Toxic
41233001
Forbis et al. 1985
Supplemental
Rainbow trout
(1Oncorhynchus mykiss)
static
32.01
0.51 ppb ai
(nominal)
Very Highly
Toxic
41233002
Forbis et al. 1985
Supplemental
Rainbow trout
(1Oncorhynchus mykiss)
flow-through
44.42
0.07 ppb ai
(measured)
Very Highly
Toxic
43358311
Baer 1994
Acceptable
Bluegill sunfish
(Lepomis macrochirus)
static
32.01
0.69 ppb ai
(nominal)
Very Highly
Toxic
41215202
Forbis et al. 1985
Supplemental
Bluegill sunfish
(Lepomis macrochirus)
flow-through
44.42
0.23 ppb ai
(measured)
Very Highly
Toxic
43358312
Baer 1994
Acceptable
Fathead minnow
(Pimephales promelas)
static
98.03
0.18 ppb ai
(nominal)
Very Highly
Toxic
41215201
Ward 1984
Supplemental
1 Emulsifiablc concentrate formulation
2Wettable powder formulation
3SS-isomer (Asana)
4.1.2.2 Freshwater Fish: Chronic Exposure (Early Life Stage and Reproduction)
Studies
A freshwater fish early life-stage test using the esfenvalerate TGAI was required for
esfenvalerate because the end-use product is expected to be transported to water from the
intended use site, and the following conditions are met: (1) the pesticide is intended for use such
that its presence in water is likely to be continuous or recurrent regardless of toxicity, and (2) any
aquatic acute LC50 or EC50 is less than 1 mg/1 (ppm). Results of the study are presented in Table
4-3. Studies using fenvalerate as the test material did not provide a more sensitive estimate of
chronic toxicity. One study using the fathead minnow determined a LOAEC of 0.25 ppb ai and a
NOAEC of 0.13 ppb ai (MRID 09700009). No other studies were available.
Table 4-3. Chronic Toxicity of Esfenvalerate to Freshwater Fish.
Species
%ai
LOAEC/NOAEC
Endpoints Affected
Reference
(MRID, Author)
Study
Classification
Fathead minnow
(Pimephales
promelas)
96.0
0.21 ppb ai /
0.09 ppb ai
(measured)
Number of spawns per
female, survival and
growth of fry
Accession # 97000
Windberg 1978
Acceptable
Despite providing a more sensitive value than the fenvalerate study, there is uncertainty
associated with the LOAEC in the esfenvalerate chronic study, since it is a greater value than
three of the acute toxicity values listed in Table 4-2. Additionally, the NOAEC is greater than
the acute LC50 chosen to assess acute risk. Therefore, an estimate of the chronic NOAEC for
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freshwater fish will be calculated using the ratio of the acute LC50 to the chronic NOAEC for the
fathead minnow (Pimephales promelas). The acute-to-chronic ratio (ACR) of these values is
2.0. With application of this to the LC50 of 0.07 ppb ai from MRID 43358311, the estimated
value of the NOAEC for freshwater fish and the CRLF is 0.035 ppb ai. This value will be used
in this assessment to estimate the chronic risk of esfenvalerate to the CRLF.
4.1.2.3 Freshwater Fish: Sublethal Effects and Additional Open Literature
Information
No suitable studies on sublethal effect to fish were available in ECOTOX.
4.1.3 Toxicity to Freshwater Invertebrates
Toxicity studies on freshwater invertebrates were evaluated to assess the potential for uses of
esfenvalerate to produce indirect effects to the aquatic phase CRLF via a reduction in
invertebrate prey. Five acute studies with the waterflea (Daphnia magna) with the TGAI and
formulated products are available, along with one chronic study with Daphnia. The results of
these studies are presented in the sections below.
4.1.3.1 Freshwater Invertebrates: Acute Exposure (Mortality) Studies
A freshwater aquatic invertebrate toxicity test using the TGAI is required to establish the toxicity
of esfenvalerate to aquatic invertebrates. The preferred test species is Daphnia magna. Results
of studies using the technical grade material or formulated product are presented in AI 0-day
sediment study with midge (Chironomus tentans) larvae (MRID 46591505) is also available.
This is a non-guideline study that has not received secondary review within EFED; therefore,
without further review the uncertainty of the results is not known. However, it does provide
some information regarding the toxicity of sediment contaminated with esfenvalerate as well as
an estimate of the acute toxicity (LC50 and EC50) of pore-water concentrations. Sediment toxicity
was determined to be 1000 ppb ai and 450 ppb ai based on survival and dry weight, respectively.
Pore-water toxicity was determined to be 0.93 ppb ai and 0.41 ppb ai based on survival and dry
weight, respectively. These estimates are similar to those for open water determined for .D.
magna. Since higher concentrations of esfenvalerate are found in the pore water, and because
the D. magna study with fenvalerate provides a more sensitive endpoint, the D. magna EC50 will
be used with the pore water concentration estimates to determine risk to aquatic invertebrates.
Table 4-4. All studies indicate that esfenvalerate technical and formulations are very highly
toxic to freshwater aquatic invertebrates. One study with the emulsifiable concentrate (MRID
41798301) produced the most sensitive endpoint among the esfenvalerate studies; however, the
water samples used to determine test concentrations in this study were determined to be
contaminated and the reliability of the results from this study is uncertain. With the exception of
this study, however, the toxicity values for formulated products and the TGAI are similar;
however, results from a study with fenvalerate as the test material (MRID 41891914) are also
presented, since this study provides a more sensitive estimate of the EC50 for aquatic
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invertebrates. The LC50 value of 0.05 ppb ai from this study will be used in the assessment of
risk to aquatic invertebrates inhabiting the water column.
AlO-day sediment study with midge (Chironomus tentans) larvae (MRID 46591505) is also
available. This is a non-guideline study that has not received secondary review within EFED;
therefore, without further review the uncertainty of the results is not known. However, it does
provide some information regarding the toxicity of sediment contaminated with esfenvalerate as
well as an estimate of the acute toxicity (LC50 and EC50) of pore-water concentrations. Sediment
toxicity was determined to be 1000 ppb ai and 450 ppb ai based on survival and dry weight,
respectively. Pore-water toxicity was determined to be 0.93 ppb ai and 0.41 ppb ai based on
survival and dry weight, respectively. These estimates are similar to those for open water
determined for .D. magna. Since higher concentrations of esfenvalerate are found in the pore
water, and because the D. magna study with fenvalerate provides a more sensitive endpoint, the
D. magna EC50 will be used with the pore water concentration estimates to determine risk to
aquatic invertebrates.
Table 4-4. Acute Toxicity of Esfenvalerate to Freshwater Invertebrates.
Species
study type
%ai
48-hr ECso1
Toxicity
Category
Reference
(MRID, Author)
Study
Classification
Waterflea
(Daphnia magna)
static
97.6
(TGAI)
fenvalerate
0.05 ppb ai
Very Highly
Toxic
41891914
Baer 1991
Acceptable
Waterflea
(Daphnia magna)
static
98.6
(TGAI)
0.9 ppb ai
Very Highly
Toxic
40444002
Hutton 1987
Acceptable
Waterflea
(Daphnia magna)
static
8.42
0.008 ppb ai
Very Highly
Toxic
41798301
Baer 1991
Supplemental
Waterflea
(Daphnia magna)
static-renewal
44.43
0.15 ppb ai
Very Highly
Toxic
43758313
Baer 1994
Supplemental
Waterflea
(Daphnia magna)
static
8.42
0.33 ppb ai
Very Highly
Toxic
42492601
Baer 1992
Supplemental
Waterflea
(Daphnia magna)
static
15.8
0.24 ppb ai
Very Highly
Toxic
42492602
Baer 1992
Acceptable
1 All EC50s reported as mean measured concentrations.
2Asana emulsifiable concentrate formulation.
3Wettable powder formulation.
4.1.3.2 Freshwater Invertebrates: Chronic Exposure (Reproduction) Studies
A freshwater aquatic invertebrate life-cycle test using the TGAI was required for esfenvalerate,
since the end-use product is expected to be transported to water from the intended use site, and
the following conditions are met: (1) the pesticide is intended for use such that its presence in
water is likely to be continuous or recurrent regardless of toxicity, and (2) aquatic acute LC50 or
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EC50 is less than 1 mg/1. The preferred test species is Daphnia magna. Results of the test are
presented in Table 4-5.
Table 4-5. Chronic Toxicity of Esfenvalerate to Freshwater Invertebrates.
Species
%ai
LOAEC/NOAEC
Endpoints Affected
Reference
(MRID, Author)
Study
Classification
Waterflea
(Daphnia magna)
98.6
0.079 ppb ai /
0.052 ppb ai
(measured)
Number of young,
survival and growth
40444001
Hutton 1987
Acceptable
Since the fenvalerate D. magna 48-hr EC50 will be used for estimates of acute risk to aquatic
invertebrates, the NOAEC presented in Table 4-5 for esfenvalerate cannot be used since it is
approximately equal to the 48-hr fenvalerate EC50. However, no reliable D. magna chronic
studies with fenvalerate were found. Therefore an estimate of a fenvalerate D. magna NOAEC,
calculated using the ACR from the esfenvalerate data was used. The ACR in this case is
determined using the most sensitive and reliable 48-hr EC50 (0.15 ppb ai) for esfenvalerate (from
MRID 43758313) and the NOAEC of 0.052 ppb ai. These result in an ACR of 2.88. Thus, an
estimate of a fenvalerate life cycle NOAEC for freshwater invertebrates based on this ACR and
the fenvalerate 48-hr EC50 of 0.05 ppb ai is 0.017 ppb ai.
4.1.3.3 Freshwater Invertebrates: Sublethal Effects and Open Literature Data
Two suitable studies were found in the ECOTOX literature database that provides further
information on the potential effects of esfenvalerate on aquatic invertebrates. All of these studies
utilized fenvalerate as the test substance, which is closely related to esfenvalerate.
Reynaldi et al. (2006) exposed/), magna to sublethal (0.1, 0.3, 0.6, and 1.0 ppb ai, and also 0
ppb ai for controls) concentrations of fenvalerate for 24 hours and observed effects on feeding
activity and body size. Reduced feeding activity and smaller body size was observed in D.
magna exposed to 0.3 ppb ai and higher concentrations. Delayed maturation was observed at
concentrations of 0.6 ppb ai and higher. Although filtering (feeding) rates recovered within 2
days after exposure, long-term effects due to reduced feeding, such as growth retardation, did
occur. Growth retardation leading to delayed maturity affects freshwater invertebrates at the
population level, as this affects population dynamics through delayed reproduction. Therefore,
this study provides an indication that even short-term sublethal exposure to fenvalerate (and
presumably esfenvalerate) may have the effect of reducing populations of freshwater aquatic
invertebrates. However, these effects are at levels above the selected acute and chronic
measurement endpoint values.
Day and Kaushik (1987) studied the chronic effects of fenvalerate on the crustacean, I). galeata
mendotae, by estimating alterations in life table parameters that indicate population effects that
may result from exposure. D. galeata mendotae were raised through several generations, and
adults of the final generation were exposed to 0, 0.005, 0.01, 0.05, or 0.10 ppb ai fenvalerate
from a stock solution of 30% ai emulsifiable concentrate (EC) formulated product. An
additional EC control containing the EC without fenvalerate was included, and it was determined
that the other ingredients did not have a toxic effect in the experiment. Survivorship was lower
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in all fenvalerate treatments except the 0.005 ppb concentration, in which survivorship was
significantly higher. No young were produced at the 0.10 ppb concentration, and the average
number of young produced at the 0.01 and 0.05 ppb concentrations were reduced due to lower
survivorship. The average brood size was reduced in all treatments. Life table parameters were
affected by the exposure to fenvalerate. The intrinsic rate of increase was reduced in the 0.05
ppb group and was reduced to 0 in the 0.10 ppb group. The net reproductive rate was reduced in
the 0.01 ppb treatments and higher, and generation time was reduced in these treatments, as well.
This study provides additional information about chronic effects on aquatic invertebrates, and
also substantiates the potential for effects on populations that result from sublethal exposures to
individuals.
4.1.4 Toxicity to Aquatic Plants
No laboratory studies were available that examined the effects of esfenvalerate in aquatic plants.
4.1.5 Freshwater Field Studies
Mesocosm Study
A mesocosm study (MRID 41573901) was submitted to EFED as a rebuttal to a presumption of
hazard to aquatic systems resulting from a worst case exposure scenario assumed by OPP. In
this study, nine 0.1-hectare ponds were treated with low, medium, or high doses of esfenvalerate
(three ponds per treatment), and three additional ponds that did not receive esfenvalerate served
as controls. Treatments were meant to simulate exposure to aquatic systems through both drift
and runoff, where 10 drift events and five runoff events were simulated to provide total
esfenvalerate loads of 0, 232.5, 4125, and 23270 mg ai/pond for the control, low, medium, and
high treatments, respectively. Observations were made on effects to phytoplankton,
zooplankton, macroinvertebrate and juvenile fish populations occurring within multiple zones
(benthic, littoral, open water) of the ponds throughout the study. At the end of the study,
additional measurements were made on the relative health of populations of fish exposed during
the study.
Effects on phytoplankton and emergent aquatic vegetation were not observed. Significant effects
were not observed on the animal taxa studied in the ponds receiving the low treatment, but
eradication of some insect populations and reductions in small fish were found in both the
medium and high treatment levels. Adverse effects were apparent almost immediately in aquatic
insect populations. The most dramatic population reductions in aquatic invertebrate species were
apparent in benthic samples when they were compared to controls and open-water and littoral
samples. This result is particularly significant because esfenvalerate residues are expected to
occur predominately in the sediment.
Significant changes in relative health of the fish populations studied at the end of the experiment
were not observed, and the authors dismissed any long term effects of esfenvalerate on fish
populations. However, the decline in populations of certain aquatic zooplankton and
macroinvertebrates at times that coincide with fish reproduction will represent a decrease in a
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significant food base which will affect fish larval growth and possibly year-class strength.
Furthermore, the comparative applicability of this study to aquatic environments outside of the
study area (Alabama) is debatable. Changes in aquatic chemistry during the study (increased
alkalinity and rising pH from supplemental fertilization) appeared to affect esfenvalerate
exposure potential in the study and may mask higher toxicity concerns for esfenvalerate.
Mesocosm and Field Studies from Open Literature
Bouldin et al. (2004) examined the effect of esfenvalerate on aquatic invertebrates in an
agricultural ditch mesocosm. A storm event (0.64 cm on a 20.23-ha field) producing runoff with
esfenvalerate was simulated in an agricultural drainage ditch. Aqueous grab samples and a
composite sediment sample from several locations were collected prior to the application.
Aqueous and sediment samples were then taken after application at 0.5-, 3-, and 24 hours and 28
days post application at 0, 20, 80, 200, and 600 m downstream (also at 56 days for sediment).
Reference upstream samples were also collected at -10 m. These were analyzed for
esfenvalerate residues and were used in aqueous and sediment toxicity tests with fish and
invertebrates.
Toxicity tests were conducted on an aquatic invertebrate (Ceriodaphnia dubia) and a fish
(Pimphalespromelas), and sediment toxicity tests were conducted with midge (Chironomus
tentans). The highest concentration of esfenvalerate was detected at the injection point (0 m) at
3 hours post application. Survival of C. dubia and P. promelas was 0% at 0 and 20 m at 0.5 and
3 hours post application. At 3 hours post application, survival of C. dubia was 0% at 80 m and
was 17.5 % fori5, promelas. Survival was >72.5% for all other times and distances, with the
exception of C. dubia at 80m 24 hours post application (45 ± 44%) and P. promelas at 80 m 28
days post application (60 ±25.8 %). Survival and growth of Chironomus tentans was
significantly lower than control at the injection site only, but at all sampling times. Survival was
highest 3 hours post application (25 ±16%) and declined through Day 56 to 6.3 ± 7.4%.
Pesticides were also measured in plant material at 20, 80, 200 and 6000 m from the injection site
at 3 hours, 24 hours, 28 days, and 56 days post application. Concentrations in plant material
were highest at 20 m, 3 hours post application (2010.34 ppb) and declined with distance and
time.
The application rate that the runoff event was expected to simulate was not reported, and likely
the amount of esfenvalerate that would reach surface water via runoff would vary with
environmental conditions. The water velocity in this study was measured at 0.04 m/s, so it is not
known how these results, especially for sediments, would compare to a faster moving system.
However, this study is useful for this assessment, since it provides an indication of the potential
effects of esfenvalerate in an aquatic system.
Pieters et al. (2005) investigated the effects of fenvalerate under field conditions (including food
restriction) on D. magna. The main goal of this study was to examine the effects of low food
conditions on life history characteristics of Daphnia magna, especially the intrinsic rate of
increase, during pulses of pesticide exposure. Fenvalerate was used as a model pesticide, but the
study does provide some information on the effects of this pesticide under field conditions. D.
magna were exposed to control, 0.03, 0.1, 0.3, 0.6, 1.0, and 3.2 ppb fenvalerate concentrations
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(nominal) for 24 hours under two different feeding regimes (low and high). The effect on the
intrinsic rate of increase was measured over the course of 21 days post-exposure. Under both
food levels, the highest concentration caused 100% mortality by Day 8 post-exposure, and most
mortality in all groups was complete by this day. In the high food group, mortality did not
exceed 35% in any test concentration group, whereas in the low food group mortality was higher
in all test concentrations above 0.1 ppb. Low food conditions significantly increased age at first
reproduction and decreased mean brood number, mean brood size, and cumulative reproduction
per living female by the end of the test (Day 21). As a result, the intrinsic rate of increase was
significantly lower in the low food concentration test groups, indicating that greater detrimental
population effects would be expected under these conditions.
4.2 Evaluation of Terrestrial Ecotoxicity Studies
Data collected on birds, mammals, terrestrial plants, and terrestrial insects are utilized to estimate
direct effects to the terrestrial phase CRLF resulting from acute and chronic exposure, indirect
effects to the CRLF resulting from loss of prey and loss/disturbance of riparian, upland, and
dispersal habitat, and modification of Critical Habitat PCEs. Toxicity endpoints available for
this assessment and the endpoints actually selected for quantitative assessment of direct and
indirect effects to the CRLF are summarized in the sections below.
4.2.1 Toxicity to Birds
4.2.1.1 Birds: Acute Exposure (Mortality) Studies
No terrestrial phase amphibian studies are available for esfenvalerate. Therefore birds are used
as a surrogate for the terrestrial phase CRLF. An oral toxicity study using the technical grade of
the active ingredient (TGAI) is required to establish the acute toxicity of esfenvalerate to birds.
Two dietary studies using the TGAI are also required to establish the subacute toxicity to birds.
The preferred guideline test species is mallard (a waterfowl) or Northern bobwhite (an upland
gamebird). For esfenvalerate, acute exposure studies are available for the guideline species.
These data indicate that on an acute oral basis, esfenvalerate is moderately toxic to an upland
game bird and is slightly toxic to practically non-toxic to birds on a subacute basis (Table 4-6).
Studies with fenvalerate did not provide more sensitive endpoint values.
Table 4-6. Acute Oral and Subacute Dietary Toxicity of Esfenvalerate to Birds.
Species
% ai
Endpoint
Toxicity
Category
Reference
(MRID, Author)
Study
Classification
Acute Oral
Northern bobwhite
(Colinus virginianus)
98.6
LD50 = 381 mg ai/kg-
bw
Moderately
Toxic
41698401
Campbell et al. 1991
Acceptable
Subacute Dietary
Northern bobwhite
0Colinus virginianus)
98.6
LC50 > 5620 ppm ai
Practically
Non-toxic
41637803
Driscoll et al. 1990
Acceptable
Mallard
(Anas platyrhynchos)
98.6
LC50 = 4894 ppm ai
Slightly
Toxic
41637802
Driscoll et al. 1990
Acceptable
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4.2.1.2 Birds: Chronic Exposure (Chronic/Reproduction) Studies
Avian reproduction studies using the TGAI are required when birds may be subject to repeated
or continuous exposure to esfenvalerate; however, avian reproduction data have not been
submitted for esfenvalerate. Two studies were submitted for fenvalerate (Fink and Beavers,
report #109-122 and 109-123, MRIDs 00037111 and 00037112, respectively). These studies
were determined to be scientifically sound, and their results were determined to be inconclusive,
but suggested the possibility that fenvalerate may result in reproductive effects in birds.
Cracking of eggs was observed in the study and was determined to be the result of exposure to
fenvalerate; however, the effect was not great enough to affect the overall reproductive success
of the test animals. The reviewer concluded that this may not be the case in the field, since eggs
are incubated in an incubator in lab tests and are not handled with the same care in the field.
There was also some question over the amount of fenvalerate contained in the highest treatment
level (125 ppm), which actually contained, based on samples tested, 60 - 85 ppm. This has
introduced uncertainty with the results. Based on this study, however, an estimate of the
LOAEC and NOAEC may be determined to be 25 and <25 ppm, respectively, although RQs
determined with this value will have uncertainty due to the study and the lack of a definitive
NOAEC endpoint.
Avian reproductive data have been requested in previous risk assessments, but they have not
been submitted to date.
4.2.1.3 Birds: Sublethal Effects and Open Literature Data
No studies were available in the ECOTOX database that describe sublethal effects on birds.
4.2.2 Toxicity to Mammals
Data submitted to OPP's Health Effects Division (HED) in order to estimate human risks are
used to determine the risks to wild mammals. For purposes of estimating non-target wild
mammal risk, an acute-oral LD50 study and a two-generation reproduction study with the
laboratory rat (Rattus norvegicus) are used.
4.2.2.1 Wild Mammals: Acute Exposure (Mortality) Studies
Previous ecological risk assessments for esfenvalerate have included lists of several acute oral
toxicity studies with laboratory rats (e.g., see EFED risk assessment for California section 24C
dated October 14, 1999). However, many of these have been performed with formulated
products or test substances containing esfenvalerate and other active ingredients. HED's
toxicology chapter for re-registration of esfenvalerate (dated August 23, 2004, obtained via their
Integrated Hazard Assessment Database) provides an endpoint with technical grade
esfenvalerate, as does a more recent up-and-down study (MRID 46765601) (Table 4-7). Based
on these values, esfenvalerate is moderately toxic to small mammals. Since the more recent
study provides the more sensitive value, it will be used in this assessment. This value has been
cross-validated with HED to ensure it is the value they have chosen to use in their assessments.
A more sensitive endpoint based on studies with fenvalerate was not found.
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Table 4-7. Toxicity of Esfenvalerate to Mammals.
Species
% ai
Endpoint
Toxicity Category
Reference
(MRID, Author)
Study
Classification
Laboratory rat
(Rattus norvegicus)
97.0
LD50 = 87.2
mg/kg-bw
Moderately toxic
00144973
Bilsback et al. 1984
Acceptable
Laboratory rat
(Rattus norvegicus)
99.09
LD50 = 59.0
mg/kg-bw
Moderately toxic
46765601
Finlay, 2005
Acceptable
4.2.2.2 Wild Mammals: Chronic Exposure (Chronic/Reproduction) Studies
Chronic toxicity data for mammals are needed to assess the potential for esfenvalerate to induce
indirect effects to the terrestrial phase CRLF via a reduction in prey base due to chronic effects
of prey items. Chronic tests are not conducted on wild mammals, so the two-generation rat
reproduction study required by HED is used as a substitute. The study presented in Table 4-8 is
included in HED's toxicology chapter as referenced above for acute toxicity. The
NOAEL/NOAEC from this study will be used to estimate chronic toxicity to mammals. Studies
with fenvalerate did not provide a more sensitive endpoint value.
Table 4-8. Chronic Toxicity of Esfenvalerate to Mammals.
Species
% ai
Toxicity Values
Endpoints Affected
Reference
Study
(MRID, Author)
Classification
Laboratory rat
98.8
Parental Systemic:
Dermal lesions,
43489001
Acceptable
(Rattus
LOAEC=75 ppm ai
decreased body
Biegel 1994
norvegicus)
(4.21 mg/kg-bw/day,
weight
?,(?)
NOAEC <75 ppm ai
Decreased pup
Offspring:
weight, decreased
LOAEC=100 ppm ai
litter size, increased
(7.18 mg/kg-bw/day,
subcutaneous
?)
hemorrhage
NOAEC=75 ppm ai
(5.56 mg/kg-bw/day,
?)
4.2.2.3 Wild Mammals: Sublethal Effects and Open Literature Information
Most available open literature studies in ECOTOX described relevant sublethal effects other than
effects on reproduction. None of these studies provided a more sensitive endpoint than reported
in guideline studies. One study did, however, find a dose-dependent reduction in motor function
in rats (ED30 =1.2 mg/kg-bw) for esfenvalerate, indicating the possibility of effects on neuronal
transmission. Such effects could potentially alter behavior in wild mammals, making them at
least temporarily more susceptible to predation.
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4.2.3 Toxicity to Non-Target Terrestrial Invertebrates
4.2.3.1 Guideline Honeybee Toxicity Studies
Toxicity studies on terrestrial invertebrates are utilized to assess the potential for esfenvalerate to
induce indirect effects to the terrestrial phase CRLF via a reduction in invertebrate prey base.
The acute contact LD50, using the honey bee, Apis mellifera, is a single-dose laboratory study
designed to estimate the quantity of toxicant required to cause 50% mortality in a test population
of bees. One acute contact study is available for honeybees (Table 4-9). Based on this value,
esfenvalerate is classified as highly toxic to honey bees on an acute contact basis. Studies with
fenvalerate did not provide a more sensitive endpoint value.
Table 4-9. Toxicity of Esfenvalerate to Non-Target Terrestrial Insects.
Species
% ai
Endpoint
Toxicity
Category
Reference
(MRID, Author)
Study
Classification
Honeybee
(Apis mellifera)
98.6
LD50 = 0.017 (ig/bee
(acute contact)
Highly toxic
41698402
Hoxter and Smith 1990
Acceptable
4.2.3.2 Non- Target Terrestrial Invertebrate Studies from Open Literature
Further information on toxicity of fenvalerate to the earthworm (Eisenia foetida) is available
from the ECOTOX database (Roberts and Dorough 1984, ECOTOX ref. # 40531). In this study,
acute contact toxicity with fenvalerate was tested by exposing the earthworm to technical grade
fenvalerate soaked into a filter paper for 48 hours. Based on this study, the authors considered
fenvalerate to be "very toxic," with an acute contact toxicity measured at 74.1 jag ai/cm2. EFED
has not established an acute contact toxicity rating based on these units, and it is not known from
this study how much active ingredient the earthworms were exposed to. However, this study
does provide some information by which to make a qualitative judgment of the hazard of
esfenvalerate to soil-dwelling invertebrates. Reduction of parasitism of pest species by
beneficial parasitoid wasps has also been observed, as well as avoidance of treated areas by
pollinators (Awchar et al. 1995, ECOTOX Reference # 92825).
4.2.4 Toxicity to Terrestrial Plants
Guideline studies with terrestrial plants are not available for esfenvalerate or fenvalerate. Some
ancillary information is available in the ECOTOX database on fenvalerate that provide some
information about the potential hazard of esfenvalerate to plants.
Toscano et al. (1982, ECOTOX ref. #41092) found no effects of fenvalerate on lettuce.
Fenvalerate (2.4 EC) was applied via backpack sprayer at 0.22 kg ai/ha (0.20 lbs ai/ac), and
lettuce plants received either one or two treatments over the course of approximately 1.5 months.
No difference in growth (measured in mass) was observed between plants treated with
fenvalerate one or two times and the untreated controls.
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In contrast with the above study, two studies did observe detrimental effects of fenvalerate on
plants, though neither provides enough information to calculate an endpoint that can be used
quantitatively. Chauhan et al. (1999, ECOTOX Ref. #72820) tested the dose-response of
fenvalerate on onion root growth and cytogenesis. Onions were grown in test concentrations of
fenvalerate of 7, 14, and 28 ppm for five days, and root growth compared to the control was
determined on the fifth day. The EC50 was calculated as the concentration that inhibited growth
by 50%, and this was determined to be 14.25 ppm. Through examinations of cells at the onion
root tip, the authors concluded that growth reductions were caused by chromosome and mitosis
aberrations. El-Daly (2006) tested germination and growth of radishes following exposure to
fenvalerate. Radish seeds were germinated on moist filter paper containing 1-1000 M
concentration (0.42 - 420 mg/L) of fenvalerate. Germination and plant growth was observed
immediately afterward. The study noted that with fenvalerate, an increase in growth was
observed in some growth parameters at the lowest levels, but a decrease was observed at the
highest levels. The authors also noted a decrease in percent germination, which was also not
dose-dependent.
4.3 Use of Probit Slope Response Relationship to Provide Information on the Endangered
Species Levels of Concern
The Agency uses the probit dose response relationship as a tool for providing additional
information on the potential for acute direct effects to the CRLF and aquatic and terrestrial
animals that may indirectly affect the CRLF (U.S. EPA, 2004). As part of the risk
characterization, an interpretation of acute RQ for listed species is discussed. This interpretation
is presented in terms of the chance of an individual event {i.e., mortality) should exposure at the
EEC actually occur for a species with sensitivity to esfenvalerate on par with the acute toxicity
endpoint selected for RQ calculation. To accomplish this interpretation, the Agency uses the
slope of the dose-response relationship available from the toxicity study used to establish the
acute toxicity measures of effect for each taxonomic group that is relevant to this assessment.
The individual effects probability associated with the acute RQ is based on the mean estimate of
the slope and an assumption of a probit dose response relationship. In addition to a single effects
probability estimate based on the mean, upper and lower estimates of the effects probability are
also provided to account for variance in the slope, if available.
Individual effect probabilities are calculated based on an Excel spreadsheet tool IECV1.1
(Individual Effect Chance Model Version 1.1) developed by the U.S. EPA, OPP, Environmental
Fate and Effects Division (June 22, 2004). The model allows for such calculations by entering
the mean slope estimate (and the 95% confidence bounds of that estimate) as the slope parameter
for the spreadsheet. In addition, the acute RQ is entered as the desired threshold.
For esfenvalerate, mortality was observed in acute toxicity studies for freshwater fish, freshwater
invertebrates, birds, mammals, and honey bees. Where probit slopes are provided, they are used
along with their upper and lower confidence limits to estimate the probability of individual
mortality and its potential variability. In cases where they are unavailable, the default slope
assumption of 4.5 with default upper and lower slope bounds of 2 and 9 are used as per original
Agency assumptions of a typical slope cited in Urban and Cook (1986). The chance of
individual mortality will be determined using the listed species LOC as the threshold of concern
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and also the RQ determined for each taxon. These analyses are presented below in the Risk
Characterization along with calculations of RQs for each taxon.
4.4 Incident Database Review
Twelve incidents involving esfenvalerate and one incident involving fenvalerate are available in
OPP's Ecological Incident Information System (EIIS). These incidents primarily involve aquatic
animals, but incidents with terrestrial animals and plants were also reported. Many incidents
occurred after applications or spills of esfenvalerate included in mixtures with other chemicals.
Each incident is described briefly below.
Fenvalerate
• Incident # B0000-502-83 - An incident with fenvalerate occurred in Madison County, GA in
1998. The report states that over the course of the summer, a resident found birds dead on his
property. One of the birds was submitted for examination and it was determined that
fenvalerate was present in the crop contents at 164 ppm. No organophosphates or carbamates
were detected. The decision made by the Department of Parasitology, University of Georgia,
was that toxicosis was suspected but the specific toxicant was not determined. Specifically, the
report stated, "Synthetic pyrethroids, such as fenvalerate, are relatively non-toxic to warm-
blooded animals. In large amounts they can cause nervous system problems. The levels of
fenvalerate in this bird were not high enough to diagnose toxicosis as the cause of death."
Esfenvalerate
• Incident # 1000109-009 - An aerial application of esfenvalerate and azinphos-methyl (AZM) to
sugarcane in Iberville County, LA in July 1999 was suspected to have resulted in an incident
involving over 2300 freshwater fish (species of gar, buffalo, and drum). It was assumed that
the application, in concert with heavy rainfall, led to runoff that caused fish kills in three
waterways associated with the Whitewater Canal. According to the investigative reports there
was lack of agreement between the investigating teams as to what caused the fish kill,
specifically whether it was attributable to low dissolved oxygen levels or AZM. Dissolved
oxygen levels were measured and found to be satisfactory. Screening analysis detected AZM
in "low but possibly significant quantities." A panel group that reviewed the incident felt that a
combination of the two was responsible for the observed mortality, although AZM was
determined to be the "probable" cause, while esfenvalerate was determined to be a "possible"
cause.
• Incident # 1008168-001 - On May 25, 1998, a cornfield in Broadway, Rockingham County,
VA was sprayed with a mixture of Princep 4L (simazine), Extrazine II 4L (atrazine and
simazine), Asana XL (esfenvalerate), and Gramoxone Extra (paraquat). Two weeks later a
neighbor noticed five dead Canada geese (Branta canadensis) and notified the Office of
Pesticide Services, Division of Consumer Protection, Dept. of Agriculture and Consumer
Services of Virginia. An inspection was made on June 26 at which time soil and vegetation
samples were taken along the bank near the creek in which the geese were found. Substantial
concentrations of simazine, atrazine, and cyanazine were found in these samples even though
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they were taken a month after the spraying. No analyses were made for paraquat or
esfenvalerate, although the certainty with which the incident was cause by paraquat was
considered to be probable. All other chemicals involved were considered possible. The
applicator was fined $520 for spraying too close to the creek that was affected.
• Incident # 1000247-004 - A fish kill took place in Theriot Canal in LaFourche County, LA
some time before August 15, 1992, which involved an unknown amount of bass, bream, gar,
and catfish. The incident was two miles long. The notification of the fish kill was made on
August 15, but by that time the fish were in a state of advanced decay and none were taken for
analysis. Sugar cane fields are in the area and on 8/12 Asana (esfenvalerate) was sprayed on
147 acres. On 8/13 and 8/15, AZM was sprayed on a total of 270 acres. AZM was suspected
to be the more probable cause of the fish kill, with esfenvalerate listed as possible.
• Incident # 1000710-001 - On September 7, 1993, six goats and two ducks were reported to
have been exposed to esfenvalerate in an agricultural area. The effect noted was
incapacitation, but not mortality. This incident occurred in Twin Falls County, ID. Few details
are provided, and the certainty of causality by esfenvalerate was determined to be possible.
• Incident # 1002166-001 - It was reported that a spill occurred between April 28 and May 1,
1995 on a tree farm in Wautauga County, NC when an insecticide-laden tank was being towed
uphill. The tank contained esfenvalerate and lindane. Subsequently several hundred small
brook trout were found dead in a nearby stream. Soil residue analyses were made between the
spill site and the stream as well as near the edge of the stream. Tissue residue analyses were
made on live and dead stream fish in order to determine the contribution of each pesticide to
the event. Various amounts of lindane were found in soil, water and fish tissue, so this
pesticide was assigned a causality certainty rating of probable. Esfenvalerate was found in
soil, a trace in stream water and was not found in fish tissue, so it was ruled as a possible cause.
• Incident # 1003596-001 and 1002200-001 - A fish kill involving approximately 10,000 trout
took place on August 8, 1994 in Aroostook County, Maine at the Maine/New Brunswick
border where high acreages of potatoes are grown. Two compounds used just prior to the
incident on the U.S. side were Manex (maneb) and Asana (esfenvalerate); on the Canadian side
chlorothalonil had been used 5 days prior to the incident, after which occurred heavy rains.
Approximately 10,000 brook trout were found dead in a nearby pond that was fed by a brook.
These fish had recently been released from a hatchery. Three samples of water were taken
from the brook and the pond; a soil sample was taken from the bank of the brook. According to
the report all of these samples were below the detection limit for the pesticides. Three fish
tissue samples were assayed for each of the pesticides, and because of other environmental
variables, there was insufficient data to implicate these pesticides as sole causative agent in the
fishkill. The conclusion reached in the report was that the cause of the fish kill was not
determinable.
• Incident # 1006173-001 - A citizen reported that on October 2, 1997 Asana XL (esfenvalerate)
was applied at a rate of 0.02 lb a.i/acre, along with Thiodan (endosulfan) at rate of 1 qt/acre, to
treat cowpeas for curculio. In addition a 4-11-11 fertilizer had recently been applied to the
field at rate of 20 gal./acre. Five days later, it rained 3"-5" in a short amount of time, thus
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causing runoff to the nearby fishpond that resulted in a fish kill in the pond. The number and
species of fish killed was not reported. This incident occurred in Texas.
• Incident # 1003659-001 - An incident occurred in Accomack County, VA on July 1, 1996 in
which thousands of clams in a hatchery were killed when exposed to esfenvalerate, AZM, and
endosulfan. A farmer that raised the clams used water from nearby Gargatha Creek, which was
contaminated with pesticides as the result of tomato fields nearby. Runoff from these fields
contaminates nearby streams and kills shellfish.
• Incident # 1009262-113 - As part of its August, 1999 report of pesticide incidents, Scotts Co.
included a complaint from Marion County, Ohio. The complainant sprayed an apple tree with
Bug-B-Gon Multi-Insect Liquid at the rate of 4 tbs/gal and all of the leaves turned brown. The
accepted rate of spraying for a garden is 2 tablespoons/gallon and the product is not registered
for fruit trees.
• Incident # 1003781-002 - A private citizen from Ledbetter, KY, called DuPont reported that a
private citizen from Ledbetter, KY reported a fish kill in her pond in June 1996. A neighbor
had used Asana XL on his tomatoes, and a subsequent rainfall washed the Asana into the pond,
killing the fish.
• Incident # 1007984-010 - In March 1995, a spray rig containing 400 gallons of Asana and
lindane overturned on a large farm and the mixture seeped into a boggy area and nearby stream
resulting in the death of an unknown number of brook trout. The spill was contained and
remediation included removing the soil and placing it in a plastic lined bed. The contaminated
water was irrigated onto a Fraser Fir field. Charcoal was placed at the point of runoff to bind
up any future chemical seepage. This incident occurred in Ashe County, NC.
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5.0 Risk Characterization
Risk characterization is the integration of the exposure and effects characterizations. Risk
characterization is used to determine the potential for direct and indirect effects to the CRLF or
for modification to its designated critical habitat from the use of esfenvalerate in CA. The risk
characterization provides an estimation (Section 5.1) and a description (Section 5.2) of the
likelihood of effects; articulates risk assessment assumptions, limitations, and uncertainties; and
synthesizes an overall conclusion regarding the likelihood of effects to the CRLF or its
designated critical habitat (i.e., "no effect," "likely to adversely affect," or "may affect, but not
likely to adversely affect").
5.1 Risk Estimation
Risk is estimated by calculating the ratio of exposure to toxicity. This ratio is the risk quotient
(RQ), which is then compared to pre-established acute and chronic levels of concern (LOCs) for
each category evaluated (APPENDIX L). For acute exposures to the CRLF and its animal prey
in aquatic habitats, as well as terrestrial invertebrates, the LOC is 0.05. For acute exposures to
the CRLF and mammals, the LOC is 0.1. The LOC for chronic exposures to CRLF and its prey,
as well as acute exposures to plants is 1.0.
Risk to the aquatic-phase CRLF is estimated by calculating the ratio of exposure to toxicity using
l-in-10 year EECs based on the label-recommended esfenvalerate usage scenarios summarized
in Table 3-3 and the appropriate aquatic toxicity endpoint from Table 4-1. Risks to the
terrestrial-phase CRLF and its prey (e.g. terrestrial insects, small mammals and terrestrial-phase
frogs) are estimated based on exposures resulting from applications of esfenvalerate (Table 3-5
through 3.6) and the appropriate toxicity endpoint from Table 4-1. Exposures are also derived
for terrestrial plants, as discussed in Section 3.3 and summarized in Table 3-7, based on the
highest application rates of esfenvalerate use within the action area.
5.1.1 Exposures in the Aquatic Habitat
5.1.1.1 Direct Effects to the Aquatic-Phase CRLF
Direct acute effects to the aquatic-phase CRLF are based on modeled peak EECs in the water
and sediment pore-water of a small surface water body and the lowest acute toxicity value for
freshwater fish. Direct chronic risks to the CRLF are calculated using modeled 60-day EECs in
the water and pore-water and the lowest chronic toxicity value for freshwater fish. Risk
estimates were calculated from EECs occurring in both the water column and in the sediment
pore water because esfenvalerate is also expected to parse to the sediment compartment (Table
5-1). Multiple scenarios were included for some uses; these scenarios are varied by number of
applications and application method (aerial or ground) where appropriate.
Based on these RQ estimates, a "may effect" determination is made for direct effects to the
aquatic-phase CRLF for all uses as a result of acute risk due to exposure in the water
column. Acute risk due to exposure to pore water, and chronic risk is also a concern for many
uses. Sediment pore water concentrations result in fewer exceedances. Uses that require high
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numbers of applications, regardless of the maximum single application rate, also result in direct
chronic risk to the CRLF.
Table 5-1. RQs for Determination of Direct Effects to the Aquatic-Phase CRLF.
Max.
RQs
Uses
Single
App. Rate
(lbs ai/A)
No.
Apps.
App.
Method
Water Column
Pore Water
Aeute1
Chrome2
Aeute1
Chronie2
Artichoke, Dried Type Beans,
Succulent (Snap) Beans,
Carrot, Lentils, Peas
(Unspecified), Dried-Type
Peas, Pepper
0.05
3
Ground
0.66
0.31
0.06
0.11
0.05
3
Aerial
2.06
0.94
0.14
0.29
Sugarbeet
0.05
3
Ground
0.81
0.31
0.06
0.09
0.05
3
Aerial
1.96
0.74
0.11
0.20
Cucumber, Eggplant, Melons,
Cantaloupe, Honeydew, Musk
Melon, Watermelon,
Pumpkin, Squash (all or
unspecified), Summer Squash,
Winter Squash
0.05
5
Aerial
2.03
0.94
0.13
0.26
0.05
7
Ground
0.24
0.17
0.03
0.06
0.05
7
Aerial
2.17
1.31
0.19
0.34
Radish
0.05
7
Ground
0.57
0.23
0.04
0.09
0.05
7
Aerial
2.17
1.29
0.17
0.34
0.05
7
Aerial
2.16
1.26
0.17
0.34
White/Irish Potato, Turnip
0.05
10
Ground
0.59
0.29
0.04
0.09
0.05
10
Aerial
2.36
1.71
0.24
0.49
Corn (unspecified), Field
0.05
5
Aerial
2.87
1.74
0.27
0.54
Corn, Pop Corn, Sweet Corn,
0.05
20
Ground
12.40
4.23
0.70
1.40
Sunflower
0.05
20
Aerial
15.89
7.54
1.26
2.46
Cotton
0.05
10
Ground
1.53
0.74
0.11
0.23
0.05
10
Aerial
2.79
2.20
0.33
0.66
Tomato
0.05
10
Aerial
2.40
1.89
0.27
0.51
0.05
10
Ground
0.74
0.34
0.06
0.11
Non Crop Land (residential)
0.05
10
Aerial
2.64
2.31
0.36
0.69
0.05
10
Ground
0.33
0.31
0.04
0.09
Non Cropland (Right-of-Way)
0.05
10
Aerial
2.76
2.51
0.39
0.77
0.05
10
Ground
1.01
0.54
0.09
0.17
Head Lettuce
0.05
14
Aerial
12.61
7.14
1.21
2.40
0.05
14
Ground
12.10
4.89
0.84
1.69
Broccoli, Chinese Broccoli,
0.05
12
Ground
3.06
1.89
0.31
0.63
Cabbage, Chinese Cabbage,
0.05
12
Aerial
3.73
3.97
0.64
1.26
Cauliflower, Collards,
0.05
24
Ground
7.69
4.63
0.79
1.54
Kohlrabi, Mustard
0.05
24
Aerial
8.94
7.97
1.41
2.77
Christmas Tree Plantings,
0.05
25
Aerial
32.37
16.80
2.96
5.83
Conifer Plantations, Orchards,
0.05
25
Aerial
36.60
20.17
3.50
6.89
Forest Tree Nurseries, and
Forests (Forestry)
0.05
25
Ground
29.76
13.51
2.40
4.71
Christmas Tree Plantings,
0.05
25
Aerial
49.91
15.14
2.54
5.00
Conifer Plantations, Orchards,
0.05
25
Aerial
55.17
18.54
3.09
6.06
Forest Tree Nurseries, and
Forests (Nursery)
0.05
25
Ground
48.33
14.94
2.43
4.77
Almond, Filbert, Pecan,
0.075
4
Aerial
2.74
1.17
0.19
0.37
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Max. 1
l]scs Single No. App.
RQs
Water Column
Pore Water
Walnut
/\|)|K KillC
(lbs ai/A)
/\|>|>S.
iviemou
Acute1
Chronic2
Acute1
Chronic2
0.1
2
Ground
0.77
0.26
0.04
0.09
0.1
2
Aerial
3.41
0.80
0.13
0.26
0.1
2
Aerial
3.43
0.94
0.14
0.26
Apple, Apricot, Cherry,
Peach, Pear, Plum, Prune,
Nectarine
0.075
9
Aerial
3.31
2.26
0.33
0.63
0.075
9
Ground
0.93
0.37
0.06
0.11
0.075
9
Aerial
3.14
2.06
0.30
0.60
0.075
7
Aerial
3.70
1.80
0.27
0.51
0.075
7
Ground
0.49
0.29
0.04
0.09
At Plant Applications to Corn
(unspecified), Field Corn, Pop
Corn, Sweet Corn, Sunflower
0.1
1
Ground
0.86
0.31
0.06
0.11
At Plant Application to
Sugarbeet
0.1
1
Ground
0.49
0.17
0.03
0.06
Non-agricultural Uses
(Residential Non-Ag 100%
impervious surfaces)
0.2
1
Ground
0.73
0.11
0.01
0.03
0.2
2
Ground
0.79
0.23
0.04
0.06
0.2
3
Ground
0.83
0.37
0.06
0.11
Lawns and Turf Grass
0.2
3
Ground
0.86
0.40
0.06
0.11
Non-agricultural Uses (Right
of Way)
0.2
3
Ground
1.14
0.60
0.10
0.20
0.2
1
Ground
0.77
0.20
0.03
0.06
Non-agricultural Uses
(Impervious Surfaces)
0.2
1
Ground
92.33
9.91
1.31
2.57
Residential Non-Agricultural
Uses with Impervious
Surfaces
NA
1
Ground
45.47
0.02
N/A
N/A
Right-of-Way Non-
Agricultural Uses with
Impervious Surfaces
NA
1
Ground
45.50
5.86
N/A
N/A
1 Calculated using the peak EECs from PRZM-EXAMS and the rainbow trout acute LC50 of 0.07 ppb ai. Values in
bold exceed the acute endangered LOC.
2 Calculated using the 60-day EECs from PRZM-EXAMS and the chronic NOAEC (estimated with ACR) of 0.035
ppb ai. Values in bold exceed the chronic LOC.
5.1.1.2 Indirect Effects to Aquatic-Phase CRLF via Reduction in Prey (non-
vascular aquatic plants, aquatic invertebrates, fish, and frogs)
Aquatic Plants
Data are not available with which to calculate RQs for aquatic plants. Without these data we
cannot make a definitive "no effect" determination; therefore, a determination of "may effect"
to the aquatic-phase CRLF is made for all uses as a result of losses of algal food sources.
Aquatic Invertebrates
Indirect acute effects to the aquatic-phase CRLF via effects to prey (invertebrates) in aquatic
habitats are based on modeled peak EECs in the standard pond and the lowest acute toxicity
value for freshwater invertebrates. For chronic risks, 21-day EECs and the lowest chronic
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toxicity value for invertebrates are used to derive chronic RQs. A summary of the acute and
chronic RQ values for exposure to aquatic invertebrates (as prey items of aquatic-phase CRLFs)
is provided in Table 5-2. As with the RQs calculated for freshwater fish, multiple scenarios were
included that provide estimates for different numbers of applications and situations in which drift
does or does not occur.
Based on these RQ estimates, a "may effect" determination is made for indirect effects to
the aquatic-phase CRLF for all uses primarily as a result of acute risk to aquatic
invertebrates due to exposure within the water column. In many cases, acute risk is also
problematic for invertebrates exposed to pore water. Chronic risks are also a concern with uses
requiring relatively high numbers of applications.
Table 5-2. RQs for Determination of Indirect Effects to the Aquatic-Phase CRLF Through
Loss of Aquatic Invertebrate Food Base.
Max. Single
No.
Apps.
App.
Method
RQs
Uses
A pp. Rate
Water Column
Pore Water
(lbs ai/A)
Aeute1
Chronie2
Aeute1
Chronie2
Artichoke, Dried Type
0.05
3
Ground
0.92
0.71
0.08
0.24
Beans, Succulent (Snap)
Beans, Carrot, Lentils, Peas
(Unspecified), Dried-Type
Peas, Pepper
0.05
3
Aerial
2.88
2.53
0.20
0.59
Sugarbeet
0.05
3
Ground
1.14
0.76
0.08
0.18
0.05
3
Aerial
2.74
2.12
0.16
0.47
Cucumber, Eggplant,
0.05
5
Aerial
2.84
2.41
0.18
0.53
Melons, Cantaloupe,
0.05
7
Ground
0.34
0.35
0.04
0.12
Honey dew, Musk Melon,
Watermelon, Pumpkin,
Squash (all or unspecified),
0.05
7
Aerial
3.04
3.00
0.26
0.76
Summer Squash, Winter
Squash
Radish
0.05
7
Aerial
3.04
2.94
0.24
0.71
0.05
7
Ground
0.80
0.53
0.06
0.18
0.05
7
Aerial
3.02
2.88
0.24
0.71
White/Irish Potato, Turnip
0.05
10
Ground
0.82
0.59
0.06
0.18
0.05
10
Aerial
3.30
3.71
0.34
1.00
Corn (unspecified), Field
0.05
5
Aerial
4.02
4.06
0.38
1.12
Corn, Pop Corn, Sweet
0.05
20
Ground
17.36
9.94
0.98
2.88
Corn, Sunflower
0.05
20
Aerial
22.24
16.41
1.76
5.12
Cotton
0.05
10
Ground
2.14
1.71
0.16
0.47
0.05
10
Aerial
3.90
4.71
0.46
1.35
Tomato
0.05
10
Ground
1.04
0.71
0.08
0.24
0.05
10
Aerial
3.36
4.00
0.38
1.12
Non Crop Land
0.05
10
Ground
0.46
0.65
0.06
0.18
(Residential)
0.05
10
Aerial
3.70
5.00
0.50
1.47
Non Cropland (Right-of-
0.05
10
Ground
1.42
1.12
0.12
0.35
Way)
0.05
10
Aerial
3.86
5.35
0.54
1.59
Head Lettuce
0.05
14
Ground
16.94
11.12
1.18
3.47
0.05
14
Aerial
17.66
15.29
1.70
5.00
Broccoli, Chinese Broccoli,
0.05
12
Ground
4.28
4.06
0.44
1.29
Cabbage, Chinese Cabbage,
0.05
12
Aerial
5.22
8.29
0.90
2.65
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Max. Single
No.
Apps.
App.
Method
RQs
Uses
A pp. Rate
Water Column
Pore Water
(lbs ai/A)
Aeute1
Chronic2
Acute1
Chronic2
Cauliflower, Collards,
0.05
24
Ground
10.76
10.06
1.10
3.24
Kohlrabi, Mustard
0.05
24
Aerial
12.52
16.94
1.98
5.76
Christmas Tree Plantings,
0.05
25
Ground
41.66
29.76
3.36
9.82
Conifer Plantations,
0.05
25
Aerial
45.32
36.35
4.14
12.12
Orchards, Forest Tree
Nurseries, and Forests
0.05
25
Aerial
51.24
43.53
4.90
14.35
(Forestry)
Christmas Tree Plantings,
0.05
25
Ground
67.66
37.53
3.40
9.94
Conifer Plantations,
0.05
25
Aerial
69.88
37.06
3.56
10.41
Orchards, Forest Tree
Nurseries, and Forests
0.05
25
Aerial
77.24
45.88
4.32
12.65
(Nursery)
0.075
7
Ground
0.68
0.59
0.06
0.18
Apple, Apricot, Cherry,
0.075
7
Aerial
5.18
4.29
0.38
1.12
Peach, Pear, Plum, Prune,
0.075
9
Ground
1.30
0.82
0.08
0.24
Nectarine
0.075
9
Aerial
4.40
4.76
0.42
1.24
0.075
9
Aerial
4.64
4.94
0.46
1.35
0.075
4
Aerial
3.84
2.94
0.26
0.76
Almond, Filbert, Pecan,
0.1
2
Ground
1.08
0.65
0.06
0.18
Walnut
0.1
2
Aerial
4.80
2.76
0.20
0.53
0.1
2
Aerial
4.78
2.06
0.18
0.53
At Plant Applications to
Corn (unspecified), Field
Corn, Pop Corn, Sweet
0.1
1
Ground
1.20
0.76
0.08
0.24
Corn, Sunflower
At Plant Application to
Sugarbeet
0.1
1
Ground
0.68
0.47
0.04
0.12
Non-agricultural Uses
0.2
1
Ground
1.02
0.35
0.02
0.06
(Residential Non-Ag 100%
0.2
2
Ground
1.10
0.65
0.06
0.12
impervious surfaces)
0.2
3
Ground
1.16
1.00
0.08
0.24
Lawns and Turf Grass
0.2
3
Ground
1.20
1.06
0.08
0.24
Non-agricultural Uses
0.2
3
Ground
1.60
1.47
0.14
0.41
(Right of Way)
0.2
1
Ground
1.08
0.53
0.04
0.12
Non-agricultural Uses
(Impervious Surfaces)
0.2
1
Ground
129.26
33.41
1.84
5.35
Residential Non-
Agricultural Uses with
N/A
1
Ground
63.66
20.41
N/A
N/A
Impervious Surfaces
Right-of-Way Non-
Agricultural Uses with
N/A
1
Ground
63.70
20.47
N/A
N/A
Impervious Surfaces
1 Calculated using the peak EECs from PRZM-EXAMS and the D. magna acute fenvalerarte 48-hr LC50 of 0.05 ppb
ai. Values in bold exceed the acute endangered LOC.
2 Calculated using the 21-day EECs from PRZM-EXAMS and the D. magna chronic estimated life cycle NOAEC of
0.017 ppb ai. Values in bold exceed the chronic LOC.
Fish and Frog Prey Items
Fish and frogs also represent potential prey items of adult CRLFs. RQs associated with acute
and chronic direct toxicity to the CRLF (Table 5-1) are used to assess potential indirect effects to
100
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the CRLF based on a reduction in freshwater fish and frogs as food items. Based on the RQs
determined for this taxon, a "may effect" determination is expected to occur for all uses as
a result of indirect effects to the CRLF due to losses of amphibian and fish food resources.
5.1.1.3 Indirect Effects to CRLF via Reduction in Habitat and/or Primary
Productivity (Freshwater Aquatic Plants)
Data are not available with which to calculate RQs for aquatic plants. A definitive "no effect"
determination cannot be made without unknown uncertainty. Therefore, a determination of
"may effect" to the aquatic-phase CRLF is made for all uses as a result of losses of habitat
and reduction in primary productivity.
5.1.2 Exposures in the Terrestrial Habitat
5.1.2.1 Direct Effects to Terrestrial-phase CRLF
As previously discussed in Section 3.3, potential direct effects to terrestrial-phase CRLFs are
based on residues on dietary items due to spray applications of esfenvalerate.
Potential direct acute effects to the terrestrial-phase CRLF are derived by considering dose- and
dietary-based EECs modeled in T-REX for a small bird (20 g) consuming small invertebrates
(Table 3-6) and acute oral and subacute dietary toxicity endpoints for avian species. Table 5-3
provides the acute RQs based on these EECs, and LC50 and LD50 (adjusted for a 20g bird)
toxicity data presented in Table 4-1. Based on the dose-based acute RQs, a "may affect"
determination is made for uses allowing multiple applications at and above 0.075 lbs ai/Aand
single applications at and above 0.2 lbs ai/acre (pecan, apple, pear, kiwi, head lettuce, apricot,
cherry, peach, plum, prune, buildings, lawns and turf grass, mosquito breeding areas, and wide-
area general outdoor surface applications).
Table 5-3. Dietary- and Dose-Based Acute RQs for Determination of Direct Effects to the
Terrestrial-Phase CRLF.
I so
Nil 111 hoi' of
Applioiilion
Niimhor of
Diol.m-
Doso-hiisod
Soiisons
I'illO
(lbs iii/.\)
Applications'
hiisod A011I0
UQs
A011I0 R<„)s"
Field Corn (ground)
1
0.05
1
<0.01
0.03
Radish
3 to 5
0.05
2
<0.01
0.05
Artichoke, Sugarbeet (broadcast), Peanuts
1
0.05
3
<0.01
0.06
Beans (Dried, Succulent), Lentils, Peas,
Sugarcane
1
0.05
4
<0.01
0.07
Sunflower
1 to 2
0.05
4
<0.01
0.07
Collards, Mustard
2 to 3
0.05
4
<0.01
0.07
Field Corn, Cucumber, Melons (all,
1
0.05
5
<0.01
0.07
Cantaloupe, Honeydew, Musk, Water),
Pumpkin, Squash (Unspecified, Summer,
Winter), Turnip, Sugarbeet (row
application)
Eggplant, Potato (White, Irish), Pepper
1
0.05
7
<0.01
0.08
Kohlrabi
2 to 3
0.05
7
<0.01
0.08
101
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Use
Number of
Seasons
Application
rate
(lbs ai/A)
Number of
Applications1
Dietary-
based Acute
RQs
Dose-based
Acute RQs2
Broccoli, Chinese broccoli, Cauliflower
1 to 2
0.05
8
<0.01
0.08
Cabbage, Chinese cabbage
1 to 3
0.05
8
<0.01
0.08
Pop Corn, Carrot, Cotton, Tomato
1
0.05
10
<0.01
0.08
Corn, Sweet corn
1 to 2
0.05
10
<0.01
0.08
Non-cropland
N/A
0.05
10
<0.01
0.08
Forestry
N/A
0.05
25
<0.01
0.09
Pecan
1
0.075
4
<0.01
0.10
Apple, Pear, Kiwi
1
0.075
7
<0.01
0.12
Head lettuce
1 to 2
0.075
7
<0.01
0.12
Apricot, Cherry, Nectarine, Peach, Plum,
Prune
1
0.075
9
<0.01
0.13
Kennels and housing areas
N/A
0.1
1
<0.01
0.06
Almond, Filbert, Walnut
1
0.1
2
<0.01
0.09
Buildings, Lawns and turf grass,
Mosquito breeding areas
N/A
0.2
1
<0.01
0.11
General Outdoor Surfaces
N/A
0.51
1
0.01
0.29
1 Based on a single season only.
2Based on an adjusted LD50 of 274.48 mg/kg-bw for a 20g bird, values in bold exceed the acute endangered LOC of
0.1.
The avian reproduction study with fenvalerate identified aNOAEC value of <25 ppm.
Esfenvalerate is more acutely toxic than fenvalerate29, and thus may be of greater chronic
toxicity as well. Using a NOAEC of 25 ppm, 1 to 25 applications at 0.05 lbs ai/acre would result
in chronic RQs ranging from 0.27 to 0.92. Applications at 0.075 lbs ai/acre (4-9 applications)
result in chronic RQs ranging from 1.04 to 1.32; 1 or 2 applications at 0.1 lbs ai/acre would be
0.54 and 0.92, respectively; while single applications at higher rates (0.2 and 0.51 lbs ai/acre)
would range from 1.08 to 2.75.
Since the fenvalerate NOAEC is <25 ppm, and the esfenvalerate NOAEC is likely lower than
that of fenvalerate, the actual chronic RQs for esfenvalerate are expected to be higher than those
calculated above. Therefore, it is likely that, at least at higher application rates, chronic RQs for
esfenvalerate would exceed the chronic LOC. In the absence of a study that provides a definitive
chronic NOAEC value for esfenvalerate, we presume that chronic effects would also occur for
uses with lower application rates. Therefore, a "may effect" determination is made for all uses
as a result of direct chronic risk to the CRLF. Submission of an avian chronic toxicity test would
reduce uncertainties with this conclusion.
5.1.2.2 Indirect Effects to Terrestrial-Phase CRLF via Reduction in Prey
(terrestrial invertebrates, mammals, andfrogs)
29 Only one definitive acute value is available for the Mallard, for which the LD50 is 9,932 mg/kg (MRID
00096385). Other LD50 values are >2,000 and >3,000 for Northern bobwhite and partridge, respectively; LC50
values are listed as >5,000 and >10,000 for Mallards and Northern bobwhite.
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Terrestrial Invertebrates
In order to assess the risks of esfenvalerate to terrestrial invertebrates, which are considered prey
of CRLF in terrestrial habitats, the honey bee is used as a surrogate for terrestrial invertebrates.
EECs (|ig a.i./g of bee) converted from values from T-REX for small and large insects are
divided by the toxicity value for terrestrial invertebrates, which is 0.017 |ig a.i./g of bee. RQs for
terrestrial invertebrates are presented in Table 5-4. Based on these RQs, a "may effect"
determination is made for indirect effects to the CRLF as a result of losses of terrestrial
invertebrate food base. This is concluded for all uses of esfenvalerate.
Table 5-4. RQs for Terrestrial Invertebrates for Determination of Indirect Effects to the
Terrestrial-Phase CRLF.
Use
Application
rate
(lbs ai/A)
Number of
Applications1
Large
Insect RQ23
Small Insect
RQ24
Field Corn (ground)
0.05
1
50.6
5.9
Radish
0.05
2
84.7
9.4
Artichoke, Sugarbeet (broadcast), Peanuts
0.05
3
108.2
11.8
Collards, Mustard, Sunflower, Beans (Dried,
Succulent), Lentils, Peas, Sugarcane
0.05
4
123.5
13.5
Field Corn, Cucumber, Melons (all,
Cantaloupe, Honeydew, Musk, Water),
Pumpkin, Squash (Unspecified, Summer,
Winter), Turnip, Sugarbeet (row application)
0.05
5
134.1
14.7
Kohlrabi, Eggplant, Potato (White, Irish),
Pepper
0.05
7
145.9
16.5
Broccoli, Chinese broccoli, Cauliflower,
Cabbage, Chinese Cabbage
0.05
8
149.4
16.5
Corn, Pop Corn, Sweet Corn, Carrot, Cotton,
Tomato, Non-cropland
0.05
10
152.9
17.1
Forestry
0.05
25
155.9
17.1
Pecan
0.075
4
185.9
20.6
Apple, Pear, Kiwi, Lettuce (Head)
0.075
7
218.8
24.1
Apricot, Cherry, Nectarine, Peach, Plum,
Prune
0.075
9
227.1
25.3
Kennels and housing areas
0.1
1
101.8
11.2
Almond, Filbert, Walnut
0.1
2
170.0
18.8
Buildings, Lawns and turf grass, Mosquito
breeding areas
0.2
1
203.5
22.4
General Outdoor Surfaces
0.51
1
518.2
57.7
1 Based on a single season only.
2Values in bold exceed the acute LOC of 0.05.
3Uses the small insect adjusted EEC calculated in Table 3-7 and the honeybee contact LD50 of 0.017 (ig/bee.
4Uses the large insect adjusted EEC calculated in Table 3-7 and the honeybee contact LD50 of 0.017 (ig/bee.
Mammals
Risks associated with ingestion of small mammals by large terrestrial-phase CRLFs are derived
for dietary-based and dose-based exposures modeled in T-REX for a small mammal (15g)
consuming short grass. Acute and chronic effects are estimated using the most sensitive
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mammalian toxicity data. EECs are divided by the toxicity value to estimate acute and chronic
dose-based RQs as well as chronic dietary-based RQs. Based on these estimates, a "may
effect" determination is made for all uses for indirect effects to the CRLF as a result of loss
in the terrestrial mammal food base. This results from both acute and chronic risks to
mammals, except for the at-plant ground application to corn (chronic risk only).
Table 5-5. RQs for Terrestrial Mammals for Determination of Indirect Effects to the
Terrestrial-Phase CRLF.
Use
Application
rate
(lbs ai/A)
Number of
Applications1
Dose-based
Acute RQ2
Dose-based
Chronic
RQ3
Dictarv-
Chronic
RQ4
Field Corn (ground)
0.05
1
0.09
1.24
0.14
Radish
0.05
2
0.15
2.11
0.24
Artichoke, Sugarbeet (broadcast),
Peanuts
0.05
3
0.19
2.63
0.30
Collards, Mustard, Sunflower,
Beans (Dried, Succulent), Lentils,
Peas, Sugarcane
0.05
4
0.21
3.01
0.35
Field Corn, Cucumber, Melons (all,
Cantaloupe, Honeydew, Musk,
Water), Pumpkin, Squash
(Unspecified, Summer, Winter),
Turnip, Sugarbeet (row application)
0.05
5
0.23
3.27
0.38
Kohlrabi, Eggplant, Potato (White,
Irish), Pepper
0.05
7
0.25
3.55
0.41
Broccoli, Chinese broccoli,
Cauliflower, Cabbage, Chinese
Cabbage
0.05
8
0.26
3.63
0.42
Corn, Pop Corn, Sweet Corn,
Carrot, Cotton, Tomato, Non-
cropland
0.05
10
0.27
3.72
0.43
Forestry
0.05
25
0.27
3.79
0.44
Pecan
0.075
4
0.32
4.52
0.52
Apple, Pear, Kiwi, Lettuce (Head)
0.075
7
0.38
5.33
0.61
Apricot, Cherry, Nectarine, Peach,
Plum, Prune
0.075
9
0.39
5.53
0.64
Kennels and housing areas
0.1
1
0.21
2.95
0.29
Almond, Filbert, Walnut
0.1
2
0.30
4.14
0.48
Buildings, Lawns and turf grass,
Mosquito breeding areas
0.2
1
0.35
4.95
0.57
General Outdoor Surfaces
0.51
1
0.90
12.62
1.45
1 Based on a single season only.
2Based on the adjusted LD50 of 129.67 mg/kg-bw for a 15-g mammal. Values in bold exceed the acute endangered
LOC of 0.10.
3Dose-based chronic RQs determined using the adjusted NOAEL of 9.25 mg/kg-bw for a 15-g mammal. Values in
bold exceed the chronic LOC of 1.0.
4Dietary-based chronic RQs determined using the estimated NOAEC of 84.2 mg/kg/day based on the standard FDA
conversion.
Frogs
104
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An additional prey item of the adult terrestrial-phase CRLF is other species of frogs. In order to
assess risks to these organisms, dietary-based and dose-based exposures modeled in T-REX for a
small bird (20g) consuming small invertebrates are used. Based on the information presented
above, a "may effect" determination is made for the terrestrial-phase CRLF as a result of
the loss of the amphibian food base. This is as a result of acute risk to frogs; chronic risk
cannot be determined because chronic toxicity data for birds is not available.
5.1.2.3 Indirect Effects to CRLF via Reduction in Terrestrial Plant Community
(Riparian and Upland Habitat)
Guideline data are not available with which to determine the risks of esfenvalerate exposure to
terrestrial plants. Some information available from the open literature suggests that fenvalerate
reduces growth and seed emergence; however, at some test levels fenvalerate increased growth
and germination. Furthermore, the applicability of these studies to the field environment and the
comparative toxicity of fenvalerate and esfenvalerate to plants are not known. Another study
failed to find effects of fenvalerate on terrestrial plants. Although one incident of plant damage
from esfenvalerate was reported, it resulted from overuse (twice the application rate) of a product
that was not registered for the type of plant to which it was applied. Therefore, it appears that
the potential risk of esfenvalerate to terrestrial plants is low. However, since we cannot make a
definitive "no effect" determination, a preliminary determination of "may affect" to the
CRLF resulting from a reduction in the terrestrial plant community is made.
5.1.3 Primary Constituent Elements of Designated Critical Habitat
For esfenvalerate use, the assessment endpoints for designated critical habitat primary
constituent elements (PCEs) involve a reduction and/or modification of food sources necessary
for normal growth and viability of aquatic-phase CRLFs, and/or a reduction and/or modification
of food sources for terrestrial-phase juveniles and adults. Because these endpoints are also being
assessed relative to the potential for indirect effects to aquatic- and terrestrial-phase CRLF, the
effects determinations for indirect effects from the potential loss of food items are used as the
basis of the effects determination for potential modification to designated critical habitat.
5.2 Risk Description
The risk description synthesizes an overall conclusion regarding the likelihood of adverse
impacts leading to an effects determination (i.e., "no effect," "may affect, but not likely to
adversely affect," or "likely to adversely affect") for the CRLF and its designated critical habitat.
If the RQs presented in the Risk Estimation (Section 5.1) show no direct or indirect effects for
the CRLF, and no modification to PCEs of the CRLF's designated critical habitat, a "no effect"
determination is made, based on esfenvalerate's use within the action area. However, if direct or
indirect effect LOCs are exceeded, or effects may modify the PCEs of the CRLF's critical
habitat, the Agency concludes a preliminary "may affect" determination for the FIFRA
regulatory action regarding esfenvalerate. A summary of the results of the risk estimation (i.e.,
"no effect" or "may affect" finding) is provided in Table 5-6 for direct and indirect effects to the
105
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CRLF. Because effects to aquatic and terrestrial plants are not expected, these preliminary
determinations also apply to PCEs of designated critical habitat for the CRLF.
Table 5-6. Preliminary Effects Determination Summary for Esfenvalerate - Direct and
Indirect Effects to the CRLF.
Assessment Endpoint
Preliminary
Effects
Determination
Basis For Preliminary Determination
Aquatic Phase
(eggs, larvae, tadpoles, juveniles, and adults)
Survival, growth, and reproduction
of CRLF individuals via direct
effects on aquatic phases
May Affect
Acute RQs exceed the endangered acute LOC for direct effects
to the CRLF for all uses and application rates. Uses that
require high numbers of applications, regardless of their
maximum single application rate, also result in direct chronic
risk to the aquatic-phase CRLF.
Survival, growth, and reproduction
of CRLF individuals via effects to
food supply (i.e., freshwater
invertebrates, non-vascular plants,
fish, and amphibians)
May Affect
Acute RQs for aquatic invertebrates, fish, and other amphibians
exceed the endangered species LOC for aquatic animals for all
uses and application rates. Uses that require high numbers of
applications also result in exceedance of the chronic LOC for
these taxa.
Data are not available with which to quantitatively assess risk
to plants. Some data indicate that losses of aquatic vascular
and non-vascular plants as a food source should not be
expected; however, without more data risk cannot be
disregarded.
Survival, growth, and reproduction
of CRLF individuals via indirect
effects on habitat, cover, and/or
primary productivity (i.e., aquatic
plant community)
May Affect
Data are not available with which to quantitatively assess risk
to plants. Some data indicate that losses of aquatic vascular
and non-vascular plants as a food source should not be
expected; however, without more data risk cannot be
disregarded.
Survival, growth, and reproduction
of CRLF individuals via effects to
riparian vegetation, required to
maintain acceptable water quality
and habitat in ponds and streams
comprising the species' current
range.
May Affect
Data are not available with which to quantitatively assess risk
to plants. Some data indicate that losses of terrestrial plants as
a food source should not be expected; however, without more
data risk cannot be disregarded.
Terrestrial Phase
(Juveniles and adults)
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Assessment Endpoint
Preliminary
Effects
Determination
Basis For Preliminary Determination
Survival, growth, and reproduction
of CRLF individuals via direct
effects on terrestrial phase adults and
juveniles
May Affect
Dose-based acute RQs exceed the LOC for the CRLF for uses
requiring numerous applications of 0.05 lbs ai/acre (forestry
uses - 25 apps/year), multiple applications at 0.075 lbs ai/acre
and 0.1 lbs ai/acre, or single applications at higher rates.
A "no effect" determination cannot be made for uses receiving
applications of 0.05 lbs ai/acre at 10 or fewer applications/year
because of the possibility of chronic risk to the terrestrial-phase
CRLF. Chronic risk is expected at least for uses with high
application rates, but cannot be quantified with certainty for
any particular use.
Survival, growth, and reproduction
of CRLF individuals via effects on
prey (i.e., terrestrial invertebrates,
small terrestrial mammals and
terrestrial phase amphibians)
May Affect
RQs for terrestrial insects exceed the acute LOC based on
EECs for both large and small insects for all uses. Acute and
chronic RQs exceed the LOCs for small mammals for all uses.
As noted above for direct effects, indirect effects are also
expected to result from effects to terrestrial-phase amphibians
as a result of acute exposures to several uses.
Survival, growth, and reproduction
of CRLF individuals via indirect
effects on habitat (i.e., riparian
vegetation)
May Affect
Data are not available with which to quantitatively assess risk
to plants. Some data indicate that losses of terrestrial plants as
a food source should not be expected; however, without more
data risk cannot be disregarded.
Following a "may affect" determination, additional information is considered to refine the
potential for exposure at the predicted levels based on the life history characteristics (i.e., habitat
range, feeding preferences, etc.) of the CRLF. Based on the best available information, the
Agency uses the refined evaluation to distinguish those actions that "may affect, but are not
likely to adversely affect" from those actions that are "likely to adversely affect" the CRLF and
its designated critical habitat.
The criteria used to make determinations that the effects of an action are "not likely to adversely
affect" the CRLF and its designated critical habitat include the following:
• Significance of Effect: Insignificant effects are those that cannot be meaningfully
measured, detected, or evaluated in the context of a level of effect where "take" occurs
for even a single individual. "Take" in this context means to harass or harm, defined as
the following:
¦ Harm includes significant habitat modification or degradation that results in
death or injury to listed species by significantly impairing behavioral patterns
such as breeding, feeding, or sheltering.
¦ Harass is defined as actions that create the likelihood of injury to listed species
to such an extent as to significantly disrupt normal behavior patterns which
include, but are not limited to, breeding, feeding, or sheltering.
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• Likelihood of the Effect Occurring: Discountable effects are those that are extremely
unlikely to occur.
• Adverse Nature of Effect: Effects that are wholly beneficial without any adverse effects
are not considered adverse.
A description of the risk and effects determination for each of the established assessment
endpoints for the CRLF and its designated critical habitat is provided in Sections 5.2.1 through
5.2.3,
5.2.1 Direct Effects
5.2.1.1 Aquatic-Phase CRLF
The aquatic-phase considers life stages of the frog that are obligatory aquatic organisms,
including eggs and larvae. It also considers submerged terrestrial-phase juveniles and adults,
which spend a portion of their time in water bodies that may receive runoff and spray drift
containing esfenvalerate.
Acute RQs determined from EECs in the water column exceed the LOC for all uses, and as a
result a preliminary "may affect" conclusion was determined for the aquatic-phase CRLF. This
was true for all scenarios. Similar conclusions were drawn based on risks associated with
sediment pore water, although RQs did not exceed LOCs for some uses. However, acute risks
due to sediment pore water concentrations are more likely to impact organisms that are potential
food items for the CRLF, such as benthic invertebrates, and this is discussed below in Section 0,
which covers indirect effects.
The chance of individual effect (mortality) to the aquatic-phase CRLF can be determined as
described above in Section 5.1 using the acute endangered LOC (0.05) as threshold values for
effects and the actual acute RQs calculated from water column EEC. This determination uses the
probit slope of 6.0 determined from the Rainbow trout acute LC50 test that was used to calculate
RQs. At the acute endangered LOC (0.05), the chance of individual mortality is less than one in
trillion (1 in 2.3x 1019; 95% CI = 1 in 63,800 to 1 in 4.24 x 1043). This probability is low.
However, water-column acute RQs for all uses exceed the acute endangered LOC by an order of
magnitude or more, so the probability of individual mortality is much higher than this estimate.
In the water column the acute RQ for all uses is at or above 0.5 which translates to an individual
chance of mortality of greater than 1 in 28. The exception is for the ground spray label
application rate on cucumber, eggplant, melons, cantaloupe, honeydew, muskmelon,
watermelon, pumpkin, and squash, which has an acute RQ of 0.24. This value translates as an
individual probability of mortality of 1 in 10,000. Acute RQs for pore-water exposures were
lower than those for peak water column exposures with acute RQs of 0.15 or less having
individual probability of acute mortality of less than 1 in a million.
Chronic RQs exceed the chronic LOC with fewer esfenvalerate uses. A higher probability of
chronic risk is associated with esfenvalerate uses involving single applications at or above 0.2 lbs
ai/A, multiple aerial applications at or above 0.35 lbs ai/A total, or multiple ground applications
108
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above 0.5 lbs ai/A total for most uses. The exception to these is uses on head lettuce, cole crops,
and impervious surfaces which have higher acute risks at lower application rates.
Usage data (Table 2-6) indicate that, although single application rates are generally <0.1 lb ai/ac,
average annual usage is high for several uses (i.e., in the 1,000's of pounds per year). Therefore,
esfenvalerate usage is either very widespread or frequent or both. Figure 2-4 indicates high
usage in California during the time of year in which eggs and tadpoles are prevalent. Since
esfenvalerate has a variety of agricultural and non-agricultural uses, it is likely to be used
practically anywhere in the state of California. Therefore we assume 100% overlap of
esfenvalerate use with CRLF habitat.
Based on the evidence discussed above, a "Likely to Adversely Affect" determination is
made for direct effects to the aquatic-phase CRLF.
5.2.1.2 Terrestrial-Phase CRLF
All uses had dietary-based acute RQs <0.01 whereas acute dose-based RQs for birds (surrogate
for the terrestrial-phase CRLF) exceed the acute LOC for uses with single application rates at or
above 0.2 lbs ai/Aand multiple applications at and above 0.075 lbs ai/A. Since terrestrial EECs
are based on applications in a single season only, it is possible that for those crops with multiple
seasons the RQs may be higher if applications are considered over the course of one year.
However, the T-REX spreadsheet model does not have the capability to estimate EECs for
multiple seasons.
The chance of individual mortality to a CRLF in the terrestrial phase must be estimated using the
default probit slope value of 4.5 (95% CI = 2 - 9). With dietary-based acute RQs of <0.01, the
individual probability of mortality is less than 1 in a trillion (95% CI of <1 in 30,000 to <1 in
1072). For the dietary-based acute RQs at the acute endangered LOC (0.1), the chance of
individual mortality is 1 in 290,000 (95% CI = 1 in 44 to 1 in 1 x 1016). Most dose-based acute
RQ values are at or below 0.10. Of the six scenario categories above the acute LOC, five
scenarios are between 0.11 and 0.13 and the sixth, general outdoor surface uses, is 0.29. For
0.11 to 0.13, the probability of individual mortality is 1 in 125,000 to 1 in 29,000, respectively.
At an acute RQ of 0.29, the probability of individual morality is 1 in 129 (0.8%) (CI = 1 in 7 to 1
in 1.5 x 106). At the acute RQ of 0.29, the probability of individual effect is relatively high.
Therefore, these results may indicate that the possibility of individual mortality is high enough
for the CRLF to warrant concern for its exposure to esfenvalerate.
However, RQs determined by T-REX may be overestimated for a poikilotherm, as well, since
homeotherms are expected to consume a greater daily amount of food relative to body weight
due to a higher metabolism. EFED's T-HERPS spreadsheet model provides a better
characterization of the dose-based risk to the CRLF based on the estimated consumption of a
terrestrial-phase amphibian. The details of this analysis are provided in Appendix C. Based on
this analysis, dose-based acute RQs do not exceed the acute LOC under any uses.
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Sufficient data are not available for quantifying chronic risks and determining which uses would
in concert with not exceeding the acute LOC would result in a "not likely to adversely affect"
conclusion for the terrestrial-phase CRLF. Based on the logic presented in Section 5.1.2.1, it is
expected that uses especially those with relatively lower application rates would not pose chronic
risks of concern. However, it cannot be said with certainty which uses would be involved;
therefore, until such time as avian reproduction data are provided to the Agency, we assume that
chronic risk above levels of concern may be associated with all uses.
Further information on actual usage would be beneficial to making a more definite conclusion,
especially since many of the RQs are just above the LOC, and there are some assumptions built
into the analysis with T-REX that may not be realistic for all scenarios. For example, for non-
agricultural uses such as around buildings, mosquito breeding areas, and "general outdoor
surfaces," the actual amount used may vary considerably. Some of these uses are likely to be
spot treatments, and the application rate may be lower. However, these are poorly characterized
with usage information, so EFED must utilize maximum possible rates allowed on the labels.
Since RQs are near the LOC, a reduction in the application rates, especially in the numbers of
applications, is expected to reduce risk to the CRLF.
Since the assumption that esfenvalerate use overlaps all areas inhabited by the CRLF, and
because chronic risk levels can not be definitively declared below levels of concern, a
"Likely to Adversely Affect" determination is made for the terrestrial-phase CRLF for all
uses of esfenvalerate.
5.2.2 Indirect Effects to the CRLF (via reductions in prey base)
5.2.2.1 Algae (Non- Vascular Aquatic Plants)
As discussed in Section 2.5.3, the diet of CRLF tadpoles is composed primarily of unicellular
aquatic plants (i.e., algae and diatoms) and detritus. Data are not available with which to
calculate RQs for aquatic plants. However, qualitative information provided in the mesocosm
study submitted to OPP and field studies available in the open literature indicate that effects to
aquatic plants are unlikely at current use rates. A preliminary "may affect" determination was
made earlier. Since the available data suggest a low likelihood of effects to aquatic plants, a
determination of "Not Likely to Adversely Affect" is made for the aquatic-phase CRLF for
all uses as a result of losses of algal food sources.
5.2.2.2 Aquatic Invertebrates
The potential for esfenvalerate to elicit indirect effects to the CRLF via effects on freshwater
invertebrate food items is dependent on several factors including: (1) the potential magnitude of
effect on freshwater invertebrate individuals and populations; and (2) the number of prey species
potentially affected relative to the expected number of species needed to maintain the dietary
needs of the CRLF. Together, these data provide a basis to evaluate whether the number of
individuals within a prey species is likely to be reduced such that it may indirectly affect the
CRLF.
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Based on RQs calculated from EECs in the water column, a preliminary "may effect"
determination was made for indirect effects to the aquatic-phase CRLF due to effects on aquatic
invertebrates. A probit slope value is not available from the D. magna acute toxicity test with
fenvalerate that was used to estimate acute risk. Therefore, the default value of 4.5 must be used.
Based on this slope, at the acute LOC of 0.05 the chance of individual mortality to an
invertebrate that would serve as a food item for the CRLF is 1 in 4.18 x 108 (95% CI = 1 in 216
to 1 in 1.75 x 1031). However, all acute RQ values were above this value ranging from 0.34 to
129. The probability of mortality for an individual ranges from 1 in 57 to 1 in 1. These
probabilities are high, indicating that if an individual is exposed at the modeled levels it is likely
to die, and therefore population sizes may be reduced to a point that the CRLF is affected by
losses of invertebrate food items.
Given the chemical nature of esfenvalerate, effects are expected to sediment-dwelling
invertebrates. The field study from the open literature described in Section 4.0, wherein
esfenvalerate was introduced into a slow-moving irrigation ditch, indicated that esfenvalerate is
toxic to sediment-dwelling invertebrates. Therefore, based on this information and RQs
calculated for sediment-dwelling invertebrates, risk to the invertebrate community is also
expected to extend to those inhabiting sediments within surface waters.
Chronic RQs exceed the LOC for invertebrates under many of the use scenarios examined.
However, reduction in chronic risk does not change the determination for indirect effects.
Based on this evidence, as well as the assumption that esfenvalerate use overlaps all areas
in which the CRLF occurs, a "Likely to Adversely Affect" determination is made for the
aquatic-phase CRLF as a result of reduction in invertebrate food base.
5.2.2.3 Fish and Aquatic-Phase Frogs
Findings for direct effects to the CRLF extend to other amphibians and fish that may serve as
food items for the aquatic-phase CRLF. Therefore, a "Likely to Adversely Affect"
determination is made for indirect effects to the CRLF as a result of losses of amphibian
and fish food items.
5.2.2.4 Terrestrial Invertebrates
When the terrestrial-phase CRLF reaches juvenile and adult stages, its diet is mainly composed
of terrestrial invertebrates. Since esfenvalerate is an insecticide, the impact to populations of
terrestrial invertebrates is expected to be great enough to cause a reduction in invertebrate food
items for the terrestrial-phase CRLF.
The RQs for terrestrial invertebrates on the treated site are presented in Table 5-4 based on
residues expected on large and small insects determined from T-REX. In all cases, the RQs
exceed the LOC by two orders of magnitude or more. Assuming the default slope and its
associated 95% confidence interval, and based on the highest and lowest RQs determined for
terrestrial invertebrates, the chance of individual effect is expected to be 100% in all cases. The
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field study from open literature presents a conclusion that not only is esfenvalerate very toxic,
but it also results in avoidance of treated areas by insect pollinators. Therefore, some effects to
populations may be mitigated by such behaviors, but they will nonetheless be unavailable for
consumption by the CRLF.
Based on the above conclusion of high risk to terrestrial invertebrates, a "Likely to
Adversely Affect" determination is made for the terrestrial-phase CRLF based on effects to
terrestrial invertebrates that serve as food items.
5.2.2.5 Mammals
Life history data for terrestrial-phase CRLFs indicate that large adult frogs consume terrestrial
vertebrates, including mice. A preliminary "may effect" determination was made for indirect
effects to the CRLF as a result of losses of mammalian food items for the terrestrial-phase adult.
Based on a default probit slope, the estimated chance of individual effect is presented here using
the acute LOC as a threshold value, as well as RQ values. At the LOC, the chance of individual
effect is 1 in 294,000 (95% CI = 1 in 44 to 1 in 1 x 1016 [limit value, as described above]). At
the median RQ (0.27), the chance is 1 in 190 (95% CI = 1 in 7.8 to 1 in 6.5 x 106). Since the
probability of individual effect is relatively high for most uses, esfenvalerate may affect enough
individuals to impact the mammalian population present in the CRLF habitat such that its food
base is affected. Chronic risk to mammals is also a concern for all uses.
Based on these risks and the assumption that esfenvalerate uses overlap all areas inhabited
by the CRLF, a "Likely to Adversely Affect" determination is made for the CRLF due to
potential losses of mammalian food based for terrestrial-phase adults from all uses.
5.2.2.6 Terrestrial-Phase Amphibians
Terrestrial-phase adult CRLFs also consume frogs. RQ values representing direct exposures of
esfenvalerate to terrestrial-phase CRLFs are used to represent exposures of esfenvalerate to frogs
in terrestrial habitats. Since direct effects to the terrestrial-phase CRLF were identified as a result
of both acute and chronic risks. Based on these same conclusions, a "Likely to Adversely
Affect" determination is made for the terrestrial-phase CRLF due to potential reduction in
the amphibian food base.
5.2.3 Indirect Effects (via Habitat Effects)
5.2.3.1 Aquatic Plants (Vascular and Non- Vascular)
Aquatic plants serve several important functions in aquatic ecosystems. Non-vascular aquatic
plants are primary producers and provide the autochthonous energy base for aquatic ecosystems.
Vascular plants provide structure, rather than energy, to the system, as attachment sites for many
aquatic invertebrates, and refugia for juvenile organisms, such as fish and frogs. Emergent
plants help reduce sediment loading and provide stability to near-shore areas and lower
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streambanks. In addition, vascular aquatic plants are important as attachment sites for egg
masses of CRLFs.
Potential indirect effects to the CRLF based on impacts to habitat and/or primary production are
assessed quantitatively using RQs from freshwater aquatic vascular and non-vascular plant data.
These data are not available for esfenvalerate; however, information has been presented above
that lead to a conclusion that effects are not expected to aquatic plants. Based on qualitative
information presented in field and mesocosm studies, effects to aquatic plants are not expected.
Therefore, a determination of "Not Likely to Adversely Affect" is made for indirect effects
to the CRLF via effects on habitat provided by aquatic plants.
5.2.3.2 Terrestrial Plants
Terrestrial plants serve several important habitat-related functions for the CRLF. In addition to
providing habitat and cover for invertebrate and vertebrate prey items of the CRLF, terrestrial
vegetation also provides shelter for the CRLF and cover from predators while foraging. Upland
vegetation including grassland and woodlands provides cover during dispersal. Riparian
vegetation helps to maintain the integrity of aquatic systems by providing bank and thermal
stability, serving as a buffer to filter out sediment, nutrients, and contaminants before they reach
the watershed, and serving as an energy source.
Guideline toxicity tests with terrestrial plants are not available for esfenvalerate. However,
based on qualitative information presented in open literature as discussed above, effects to
terrestrial plants are not expected. Additionally, since the mechanism of action of type two
pyrethroids is to act on neuronal transmission, esfenvalerate is not expected to have high toxicity
to plants. Therefore, a "Not Likely to Adversely Affect" determination is made for indirect
effects to the CRLF as a result of reduction in terrestrial plants that serve as riparian and
upland habitat for the CRLF.
5.2.4 Modification of Designated Critical Habitat
Since risks to plants are not being assessed quantitatively, risk conclusions for designated critical
habitat are the same as those for indirect effects.
5.3 Risk Hypotheses Revisited
Table 5-7 below revisits the risk hypotheses presented in section 2.9.1. The risk hypotheses were
accepted or rejected in accordance with the "Likely to Adversely Affect," or "Not Likely to
Adversely Affect" findings in this assessment.
Table 5-7. Risk Hypothesis Revisited
Risk Hypothesis
Conclusions
Labeled uses of esfenvalerate within the action area may
directly affect the CRLF by causing mortality or by
adversely affecting growth or fecundity
Accepted for aquatic phase. "Likely to
Adversely Affect" finding.
Accepted for terrestrial phase. "Likely to
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Risk Hypothesis
Conclusions
Adversely Affect" finding.
Labeled uses of esfenvalerate within the action area may
indirectly affect the CRLF by reducing or changing the
composition of food supply
Accepted for aquatic phase. "Likely to
Adversely Affect" finding.
Accepted for terrestrial phase. "Likely to
Adversely Affect" finding.
Labeled uses of esfenvalerate within the action area may
indirectly affect the CRLF and/or adversely modify
designated critical habitat by reducing or changing the
composition of the aquatic plant community in the
ponds and streams comprising the species' current range
and designated critical habitat, thus affecting primary
productivity and/or cover
Rejected. "Not Likely to Adversely
Affect" finding for terrestrial plants.
Labeled uses of esfenvalerate within the action area may
indirectly affect the CRLF and/or adversely modify
designated critical habitat by reducing or changing the
composition of the terrestrial plant community (i.e.,
riparian habitat) required to maintain acceptable water
quality and habitat in the ponds and streams comprising
the species' current range and designated critical habitat
Rejected. "Not Likely to Adversely
Affect" finding for aquatic plants.
Labeled uses of esfenvalerate within the action area may
adversely modify the designated critical habitat of the
CRLF by reducing or changing breeding and non-
breeding aquatic habitat (via modification of water
quality parameters, habitat morphology, and/or
sedimentation)
Rejected. "Not Likely to Adversely
Affect" finding for aquatic and terrestrial
plants.
Labeled uses of esfenvalerate within the action area may
adversely modify the designated critical habitat of the
CRLF by reducing the food supply required for normal
growth and viability of juvenile and adult CRLFs
Accepted for aquatic and terrestrial phase.
"Likely to Adversely Affect" finding for
prey.
Labeled uses of esfenvalerate within the action area may
adversely modify the designated critical habitat of the
CRLF by reducing or changing upland habitat within
200 ft of the edge of the riparian vegetation necessary
for shelter, foraging, and predator avoidance
Accepted for aquatic and terrestrial phase.
"Likely to Adversely Affect" finding for
indirect effect via effects on food.
Labeled uses of esfenvalerate within the action area may
adversely modify the designated critical habitat of the
CRLF by reducing or changing dispersal habitat within
designated units and between occupied locations within
0.7 mi of each other that allow for movement between
sites including both natural and altered sites which do
not contain barriers to dispersal
Accepted. Presence of esfenvalerate in
terrestrial habitat is believed to have direct
and indirect effects on CRLF.
Labeled uses of esfenvalerate within the action area may
adversely modify the designated critical habitat of the
Accepted. "Likely to Adversely Affect"
finding for indirect effect via effects on
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Risk Hypothesis
Conclusions
CRLF by altering chemical characteristics necessary for
normal growth and viability of juvenile and adult
CRLFs
food.
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6.0 Uncertainties
6.1 Exposure Assessment Uncertainties
6.1.1 Maximum Use Scenario
The screening-level risk assessment focuses on characterizing potential ecological risks resulting
from a maximum use scenario, which is determined from labeled statements of maximum
application rate and number of applications with the shortest time interval between applications.
The frequency at which actual uses approach this maximum use scenario may be dependant on
pest resistance, timing of applications, cultural practices, and market forces.
6.1.2 Aquatic Exposure Modeling of Esfenvalerate
The standard ecological water body scenario (EXAMS pond) used to calculate potential aquatic
exposure to pesticides is intended to represent conservative estimates, and to avoid
underestimations of the actual exposure. The standard scenario consists of application to a 10-
hectare field bordering a 1-hectare, 2-meter deep (20,000 m3) pond with no outlet. Exposure
estimates generated using the EXAMS pond are intended to represent a wide variety of
vulnerable water bodies that occur at the top of watersheds including prairie pot holes, playa
lakes, wetlands, vernal pools, man-made and natural ponds, and intermittent and lower order
streams. As a group, there are factors that make these water bodies more or less vulnerable than
the EXAMS pond. Static water bodies that have larger ratios of pesticide-treated drainage area
to water body volume would be expected to have higher peak EECs than the EXAMS pond.
These water bodies will be either smaller in size or have larger drainage areas. Smaller water
bodies have limited storage capacity and thus may overflow and carry pesticide in the discharge,
whereas the EXAMS pond has no discharge. As watershed size increases beyond 10-hectares, it
becomes increasingly unlikely that the entire watershed is planted with a single crop that is all
treated simultaneously with the pesticide. Headwater streams can also have peak concentrations
higher than the EXAMS pond, but they likely persist for only short periods of time and are then
carried and dissipated downstream.
The Agency acknowledges that there are some unique aquatic habitats that are not accurately
captured by this modeling scenario and modeling results may, therefore, under- or over-estimate
exposure, depending on a number of variables. For example, aquatic-phase CRLFs may inhabit
water bodies of different size and depth and/or are located adjacent to larger or smaller drainage
areas than the EXAMS pond. The Agency does not currently have sufficient information
regarding the hydrology of these aquatic habitats to develop a specific alternate scenario for the
CRLF. CRLFs prefer habitat with perennial (present year-round) or near-perennial water and do
not frequently inhabit vernal (temporary) pools because conditions in these habitats are generally
not suitable (Hayes and Jennings 1988). Therefore, the EXAMS pond is assumed to be
representative of exposure to aquatic-phase CRLFs. In addition, the Services agree that the
existing EXAMS pond represents the best currently available approach for estimating aquatic
exposure to pesticides (USFWS/NMFS 2004).
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In general, the linked PRZM/EXAMS model produces estimated aquatic concentrations that are
expected to be exceeded once within a ten-year period. The Pesticide Root Zone Model is a
process or "simulation" model that calculates what happens to a pesticide in an agricultural field
on a day-to-day basis. It considers factors such as rainfall and plant transpiration of water, as
well as how and when the pesticide is applied. It has two major components: hydrology and
chemical transport. Water movement is simulated by the use of generalized soil parameters,
including field capacity, wilting point, and saturation water content. The chemical transport
component can simulate pesticide application on the soil or on the plant foliage. Dissolved,
adsorbed, and vapor-phase concentrations in the soil are estimated by simultaneously considering
the processes of pesticide uptake by plants, surface runoff, erosion, decay, volatilization, foliar
wash-off, advection, dispersion, and retardation.
Uncertainties associated with each of these individual components add to the overall uncertainty
of the modeled concentrations. Model inputs from the soil degradation studies represent the
upper confidence bound on the mean values that are not expected to be exceeded in the
environment approximately 90 percent of the time. No aerobic or anaerobic aquatic metabolism
studies were available for esfenvalerate. A default input parameter of twice the soil metabolism
half-life was used. For aerobic aquatic metabolism, representing esfenvalerate persistence in the
water column, this was twice the upper 90th percent bound on the mean (138 days), or 276 days.
For anaerobic aquatic metabolism, representing esfenvalerate persistence in sediment, this was
twice the anaerobic aquatic metabolism half-life (3 times the single value of 77 days, 231 days),
or 462 days. Such default inputs increase the uncertainty in aquatic exposure estimates,
particularly chronic exposures and exposures in sediment.
Mobility input values are chosen to be representative of conditions in the environment. The
natural variation in soils adds to the uncertainty of modeled values. Factors such as application
date, crop emergence date, and canopy cover can also affect estimated concentrations, adding to
the uncertainty of modeled values. Factors within the ambient environment such as soil
temperatures, sunlight intensity, antecedent soil moisture, and surface water temperatures can
cause actual aquatic concentrations to differ for the modeled values.
The aquatic exposure estimates account for the effect of labeled spray drift setbacks (450-foot
buffers for aerial ULV applications; 25-foot buffers for ground applications) on the fraction of
esfenvalerate reaching the water body as a result of drift. However, it did not account for the
effect of the setback on the amount of esfenvalerate that would reach the water body in runoff
(primarily sorbed to sediment). While the Agency would expect that the increased distance
between the field of application and the water body would result in less loads for a pesticide such
as esfenvalerate that is primarily transported on sediment, the amount or reduction cannot be
quantified. Unlike spray drift, tools are currently not available to evaluate the effectiveness of a
vegetative setback on runoff and loadings. The effectiveness of vegetative setbacks is highly
dependent on the condition of the vegetative strip. For example, a well-established, healthy
vegetative setback can be a very effective means of reducing runoff and erosion from agricultural
fields. Alternatively, a setback of poor vegetative quality or a setback that is channelized can be
ineffective at reducing loadings. Until such time as a quantitative method to estimate the effect
of vegetative setbacks on various conditions on pesticide loadings becomes available, the aquatic
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exposure predictions are likely to overestimate exposure where healthy vegetative setbacks exist
and underestimate exposure where poorly developed, channelized, or bare setbacks exist.
6.1.3 Action Area Uncertainties
This assessment differs from other assessments for the CRLF in that extensive mapping was not
used to define the action area. Instead, because the use patterns allowed on esfenvalerate labels
result in the potential for it to be used anywhere in the state of California, it was assumed that the
action area represented the entire state. Some areas may be excluded; however, usage data are
not sufficient to determine the location of such areas, and no areas are listed for exclusion on the
labels. Therefore, it is expected that the action area may be overestimated; however, this
assumption is expected to be conservative and thus protective of the CRLF.
6.1.4 Usage Uncertainties
County-level usage data were obtained from California's Department of Pesticide Regulation
Pesticide Use Reporting (CDPR PUR) database. Four years of data (2002 - 2005) were included
in this analysis because statistical methodology for identifying outliers, in terms of area treated
and pounds applied, was provided by CDPR for these years only. No methodology for removing
outliers was provided by CDPR for 2001 and earlier pesticide data; therefore, this information
was not included in the analysis because it may misrepresent actual usage patterns. CDPR PUR
documentation indicates that errors in the data may include the following: a misplaced decimal;
incorrect measures, area treated, or units; and reports of diluted pesticide concentrations. In
addition, it is possible that the data may contain reports for pesticide uses that have been
canceled. The CPDR PUR data does not include home owner applied pesticides; therefore,
residential uses are not likely to be reported. As with all pesticide usage data, there may be
instances of misuse and misreporting. The Agency made use of the most current, verifiable
information; in cases where there were discrepancies, the most conservative information was
used.
6.1.5 Terrestrial Exposure Modeling of Esfenvalerate
The Agency relies on the work of Fletcher et al. (1994) for setting the assumed pesticide residues
in wildlife dietary items. These residue assumptions are believed to reflect a realistic upper-
bound residue estimate, although the degree to which this assumption reflects a specific
percentile estimate is difficult to quantify. It is important to note that the field measurement
efforts used to develop the Fletcher estimates of exposure involve highly varied sampling
techniques. It is entirely possible that much of these data reflect residues averaged over entire
above ground plants in the case of grass and forage sampling.
It was assumed that ingestion of food items in the field occurs at rates commensurate with those
in the laboratory. Although the screening assessment process adjusts dry-weight estimates of
food intake to reflect the increased mass in fresh-weight wildlife food intake estimates, it does
not allow for gross energy differences. Direct comparison of a laboratory dietary concentration-
based effects threshold to a fresh-weight pesticide residue estimate would result in an
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underestimation of field exposure by food consumption by a factor of 1.25 - 2.5 for most food
items.
Differences in assimilative efficiency between laboratory and wild diets suggest that current
screening assessment methods do not account for a potentially important aspect of food
requirements. Depending upon species and dietary matrix, bird assimilation of wild diet energy
ranges from 23 - 80%, and mammal's assimilation ranges from 41 - 85% (U.S. Environmental
Protection Agency, 1993). If it is assumed that laboratory chow is formulated to maximize
assimilative efficiency (e.g., a value of 85%), a potential for underestimation of exposure may
exist by assuming that consumption of food in the wild is comparable with consumption during
laboratory testing. In the screening process, exposure may be underestimated because metabolic
rates are not related to food consumption.
For the terrestrial exposure analysis of this risk assessment, a generic bird or mammal was
assumed to occupy either the treated field or adjacent areas receiving a treatment rate on the
field. Actual habitat requirements of any particular terrestrial species were not considered, and it
was assumed that species occupy, exclusively and permanently, the modeled treatment area.
Spray drift model predictions suggest that this assumption leads to an overestimation of exposure
to species that do not occupy the treated field exclusively and permanently.
6.1.6 Spray Drift Modeling
Spray drift modeling was not used as extensively in this assessment as in other CRLF
assessments, due to the fact that esfenvalerate is expected to be used in all areas occupied by the
CRLF. However, it has been used to characterize the role of drift in exposure to aquatic and
terrestrial organisms as described in Section 2.0. The uncertainties associated with use of spray
drift modeling are included below.
It is unlikely that the same organism would be exposed to the maximum amount of spray drift
from every application made. In order for an organism to receive the maximum concentration of
esfenvalerate from multiple applications, each application of esfenvalerate would have to occur
under identical atmospheric conditions (e.g., same wind speed and same wind direction) and (if it
is an animal) the animal being exposed would have to be located in the same location (which
receives the maximum amount of spray drift) after each application. Additionally, other factors,
including variations in topography, cover, and meteorological conditions over the transport
distance are not accounted for by the AgDRIFT model (i.e., it models spray drift from aerial and
ground applications in a flat area with little to no ground cover and a steady, constant wind speed
and direction). Therefore, in most cases, the drift estimates from AgDRIFT may overestimate
exposure, especially as the distance increases from the site of application, since the model does
not account for potential obstructions (e.g., large hills, berms, buildings, trees, etc.).
Furthermore, conservative assumptions are made regarding the droplet size distributions being
modeled ('ASAE Very Fine to Fine' for orchard uses and ' ASAE Very Fine' for agricultural
uses), the application method (i.e., aerial), release heights and wind speeds. Alterations in any of
these inputs would decrease the area of potential effect.
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6.2 Effects Assessment Uncertainties
6.2.1 Age Class and Sensitivity of Effects Thresholds
It is generally recognized that test organism age may have a significant impact on the observed
sensitivity to a toxicant. The acute toxicity data for fish are collected on juvenile fish between
0.1 and 5 grams. Aquatic invertebrate acute testing is performed on recommended immature age
classes (e.g., first instar for daphnids, second instar for amphipods, stoneflies, mayflies, and third
instar for midges).
Testing of juveniles may overestimate toxicity at older age classes for pesticide active
ingredients that act directly without metabolic transformation because younger age classes may
not have the enzymatic systems associated with detoxifying xenobiotics. In so far as the
available toxicity data may provide ranges of sensitivity information with respect to age class,
this assessment uses the most sensitive life-stage information as measures of effect for surrogate
aquatic animals, and is therefore, considered as protective of the CRLF.
6.2.2 Use of Surrogate Species Effects Data
Guideline toxicity tests and open literature data on esfenvalerate are not available for frogs or
any other aquatic-phase amphibian; therefore, freshwater fish are used as surrogate species for
aquatic-phase amphibians. Although no data are available for esfenvalerate, the available open
literature information on esfenvalerate toxicity to aquatic-phase amphibians shows that acute
ecotoxicity endpoints for aquatic-phase amphibians are generally about 24 times less sensitive
than freshwater fish. Therefore, endpoints based on freshwater fish ecotoxicity data are assumed
to be protective of potential direct effects to aquatic-phase amphibians including the CRLF, and
extrapolation of the risk conclusions from the most sensitive tested species to the aquatic-phase
CRLF is likely to overestimate the potential risks to those species. Efforts are made to select the
organisms most likely to be affected by the type of compound and usage pattern; however, there
is an inherent uncertainty in extrapolating across phyla. In addition, the Agency's LOCs are
intentionally set very low, and conservative estimates are made in the screening level risk
assessment to account for these uncertainties.
6.2.3 Sublethal Effects
When assessing acute risk, the screening risk assessment relies on the acute mortality endpoint as
well as a suite of sublethal responses to the pesticide, as determined by the testing of species
response to chronic exposure conditions and subsequent chronic risk assessment. Consideration
of additional sublethal data in the assessment is exercised on a case-by-case basis and only after
careful consideration of the nature of the sublethal effect measured and the extent and quality of
available data to support establishing a plausible relationship between the measure of effect
(sublethal endpoint) and the assessment endpoints.
Sublethal effects to several organisms were discussed in Section 4.0. Reduction in feeding
activity, reduced body size, and reduced brood size were observed in open literature studies on
Daphnia. Reductions in motor function were also observed in laboratory rats. To the extent to
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which sublethal effects are not considered in this assessment, the potential direct and indirect
effects of esfenvalerate on CRLF may be underestimated.
6.2.4 Location of Wildlife Species
For the terrestrial exposure analysis of this risk assessment, a generic bird or mammal was
assumed to occupy either the treated field or adjacent areas receiving a treatment rate on the
field. Actual habitat requirements of any particular terrestrial species were not considered, and it
was assumed that species occupy, exclusively and permanently, the modeled treatment area.
Spray drift model predictions suggest that this assumption leads to an overestimation of exposure
to species that do not occupy the treated field exclusively and permanently.
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7.0 Risk Conclusions
In fulfilling its obligations under Section 7(a)(2) of the Endangered Species Act, the information
presented in this endangered species risk assessment represents the best data currently available
to assess the potential risks of esfenvalerate to the CRLF and its designated critical habitat.
Based on the best available information, the Agency makes a Likely to Adversely Affect
determination for the CRLF from the use of esfenvalerate. Additionally, the Agency has
determined that there is the potential for modification of CRLF designated critical habitat from
the use of the chemical. All uses of esfenvalerate are expected to affect the CRLF and its critical
habitat in both its aquatic and terrestrial phases. Buffers included on the label are not sufficient
to protect the CRLF or its potential vertebrate and invertebrate food items from exposure that is
high enough to cause acute or chronic effects. This assessment does not include extensive
mapping of estimated areas in which exposure to the CRLF is expected; instead, since
esfenvalerate use can occur anywhere in the state of California, it is assumed that use of
esfenvalerate occurs in all areas occupied by the CRLF.
A summary of the risk conclusions and effects determinations for the CRLF and its critical
habitat, given the uncertainties discussed in Section 6.0, is presented in Table 7-1. Since plant
risks were not quantitatively assessed, effects to Designated Critical Habitat are expected to be
the same as for indirect effects to the CRLF.
Table 7-1. Effects Determination Summary for Direct and Indirect Effects of Esfenvalerate
on the CRLF.
Assessment Endpoint
Effects
Determination1
Basis for Determination
Aquatic-Phase CRLF
(Eggs, Larvae, and Adults)
Direct Effects:
Survival, growth, and reproduction of
CRLF individuals via direct effects on
aquatic phases
Likely to Adversely
Affect
Acute RQs exceed the LOC for direct effects to the
CRLF for all uses and application rates. Uses that
require high numbers of applications, regardless of their
maximum single application rate, also result in direct
chronic risk to the aquatic-phase CRLF. Probability of
individual effect was determined to be high based on
RQs. Incidents indicate potential for mortality with
exposure to runoff following labeled uses. Exposure is
expected in all areas occupied by CRLF.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects to food
supply (i.e., freshwater invertebrates,
non-vascular plants, fish, and frogs)
Freshwater
invertebrates, fish,
and other amphibians:
Likely to Adversely
Affect
Acute RQs for aquatic invertebrates, fish, and other
amphibians exceed the LOC for aquatic animals for all
uses and application rates. The probability of mortality is
high for aquatic invertebrates and fish. Uses that require
high numbers of applications also result in chronic risk to
these taxa.
Non-vascular aquatic
olants: Not Likelv to
Adversely Affect
Indirect effects resulting from losses of aquatic vascular
and non-vascular plants as a food source are not expected
due to qualitative conclusion of low likelihood of effects.
Based on information gathered in a mesocosm study
submitted to OPP and from the field studies described
122
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Assessment Endpoint
Effects
Determination1
Basis for Determination
above, it appears that risk to aquatic plants is low.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat, cover, and/or primary
productivity (i.e., aquatic plant
community)
Vascular and Non-
vascular aauatic
olants: NotLikelv
to Adversely Affect
EFED does not have aquatic plant toxicity data to
estimate the risk to plants; however, indirect effects
resulting from losses of aquatic vascular and non-
vascular plants as a food source are not expected due to
qualitative conclusion of low likelihood of effects.
Based on information gathered in a mesocosm study
submitted to OPP and from the field studies described
above, it appears that risk to aquatic plants is low.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects to riparian
vegetation, required to maintain
acceptable water quality and habitat in
ponds and streams comprising the
species' current range.
Not Likely to
Adversely Affect
EFED does not have aquatic plant toxicity data to
estimate the risk to plants; however, based on studies in
available in the ECOTOX database, effects on terrestrial
plants are expected to be unlikely.
Terrestrial-Phase CRLF
(Juveniles and adults)
Direct Effects:
Survival, growth, and reproduction of
CRLF individuals via direct effects on
terrestrial phase adults and juveniles
Likely to Adversely
Affect
Acute risk to the CRLF has been identified for uses
requiring numerous applications of 0.05 lbs ai/acre
(forestry uses - 25 apps/year), multiple applications at
0.075 lbs ai/acre and 0.1 lbs ai/acre, or single
applications at higher rates. Probability of individual
effect is expected to be high. Chronic risk is also
expected for these and possibly other uses; however, data
are not available to quantify risk and determine which
uses result in chronic risk. Therefore, a conservative
conclusion is made that chronic risk may result from all
uses. Overlap of esfenvalerate use is expected in all
areas occupied by the CRLF.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via effects on prey (i.e.,
terrestrial invertebrates, small terrestrial
vertebrates, including mammals and
terrestrial phase amphibians)
Terrestrial
invertebrates: Likelv
to Adversely Affect
RQs exceed the LOCs for small and large insects in all
cases and probability of individual effect is high.
Overlap of use is expected for all areas occupied by the
CRLF.
Mammals: Likelv to
Adversely Affect
RQs exceed the acute LOC for all but one use;
probability of individual effect is high; RQs exceed the
chronic LOC for all uses. Overlap of use is expected for
all areas occupied by the CRLF.
Fross: Likelv to
Adversely Affect
Since this conclusion was drawn for direct effects to the
CRLF, risk is also presumed for other amphibians.
Indirect Effects and Effects to Critical
Habitat:
Survival, growth, and reproduction of
CRLF individuals via indirect effects on
habitat (i.e., riparian vegetation)
Not Likely to
Adversely Affect
EFED does not have aquatic plant toxicity data to
estimate the risk to plants; however, based on studies in
available in the ECOTOX database, effects on terrestrial
plants are expected to be unlikely.
123
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