Risks of Captan 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
October 18,2007
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Primary Authors:
Holly Galavotti, Biologist
Amer Al-Mudallal, Chemist
Robert Miller, Physical Scientist
Faruque Khan, Senior Physical Scientist
Secondary Review:
Christine Hartless, Wildlife Biologist
Thuy Ngyugen, RAPL
Branch Chief, Environmental Risk Assessment Branch 1:
Nancy Andrews
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1. Executive Summary 9
2. Problem Formulation 16
2.1 Purpose 16
2.2 Scope 18
2.2.1 Degradates 19
2.2.2 Mixtures 20
2.3 Previous Assessments 20
2.4 Stressor Source and Distribution 21
2.4.1 Environmental Fate Assessment 21
2.4.2 Environmental Transport Assessment 23
2.4.3 Mechanism of Action 24
2.4.4 Use Characterization 24
2.5 Assessed Species 32
2.5.1 Distribution 32
2.5.2 Reproduction 38
2.5.3 Diet 38
2.5.4 Habitat 39
2.6 Designated Critical Habitat 40
2.7 Action Area 42
2.8 Assessment Endpoints and Measures of Ecological Effect 47
2.8.1 Assessment Endpoints for the CRLF 47
2.8.2 Assessment Endpoints for Designated Critical Habitat 48
2.9 Conceptual Model 51
2.9.1 Risk Hypotheses 51
2.9.2 Diagram 52
2.10 Analysis Plan 55
2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model 55
3. Exposure Assessment 58
3.1 Label Application Rates and Intervals 58
3.2 Aquatic Exposure Assessment 60
3.2.1 Aquatic Modeling Results 62
3.2.2 Existing Monitoring Data 65
3.2.3 Spray Drift Buffer Analysis 65
3.2.4 Downstream Dilution Analysis 67
3.2 Terrestrial Animal Exposure Assessment 67
4. Effects Assessment 70
4.1 Toxicity of Captan to Aquatic Organisms 72
4.1.1 Toxicity to Freshwater Fish and Amphibians 73
4.1.2 Toxicity to Freshwater Invertebrates 73
4.1.3 Toxicity to Aquatic Plants 74
4.2 Toxicity of Captan to Terrestrial Organisms 74
4.2.1 Toxicity to Birds 75
4.2.2 Toxicity to Mammals 76
4.2.3 Toxicity to Terrestrial Invertebrates 76
4.2.4 Toxicity to Terrestrial Plants 77
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4.3 Use of Probit Slope Response Relationship to Provide Information on the
Endangered Species Levels of Concern 78
4.4 Incident Database Review 79
4.4.1 Aquatic Incidents 79
4.4.2 Terrestrial Incidents 80
4.4.3 Plant Incidents 81
5. Risk Characterization 82
5.1 Risk Estimation 82
5.1.1 Exposures in the Aquatic Habitat 83
5.1.2 Exposures in the Terrestrial Habitat 87
5.1.3 Primary Constituent Elements of Designated Critical Habitat 92
5.1.4 Action Area 94
5.2 Risk Description 99
5.2.1 Direct Effects 103
5.2.2 Indirect Effects (via Reductions in Prey Base) 106
5.2.3 Indirect Effects (via Habitat Effects) 109
5.2.4 Modification to Designated Critical Habitat 110
6. Uncertainties 112
6.1 Exposure Assessment Uncertainties 112
6.1.1 Maximum Use Scenario 112
6.1.2 Aquatic Exposure Modeling of Captan 112
6.1.3 Action Area 114
6.1.4 Usage Uncertainties 115
6.1.5 Terrestrial Exposure Modeling of Captan 115
6.2 Effects Assessment Uncertainties 116
6.2.1 Age Class and Sensitivity of Effects Thresholds 116
6.2.2 Use of surrogate species effects data 117
6.2.3 Sublethal Effects 117
7. Risk Conclusions 117
8. References 122
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LIST OF TABLES
Table 1.1 Effects Determination Summary for Captan - Direct and Indirect Effects to
CRI.I 13
Table 1.2 Effects Determination Summary for Captan - PCEs of Designated Critical
Habitat for the CRLF 14
Table 2.01 Registered Uses of Captan 19
Table 2.02 Selected Physical and Chemical Properties of Captan 22
Table 2.03 Environmental fate properties for the degradate, THPI 23
Table 2.04 Captan Foliar Application to Food Uses 25
Table 2.05. Application Rates for Use of Captan on Ornamentals 26
Table 2.06. Application Rates for Seed Treatment using Captan 27
Table 2.07. California County Level PUR Data for Captan 31
Table 2.08. California Red-legged Frog Recovery Units with Overlapping Core Areas
and Designated Critical Habitat 35
Table 2.09. Summary of Assessment Endpoints and Measures of Ecological Effects for
Direct and Indirect Effects of Captan on the California Red-legged Frog 47
Table 2.10. Summary of Assessment Endpoints and Measures of Ecological Effect for
Primary Constituent Elements of Designated Critical Habitat 50
Table 3.01. Captan Foliar Application Rates for Food Uses and modeled PRZM/EXAMS
Scenarios 60
Table 3.02. Captan Foliar Application Rates for Turf/ Ornamentals and PRZM/EXAMS
Scenarios 60
Table 3.03. PRZM/EXAM Input Parameters for Captan 61
Table 3.04. Aquatic EECs (|ig/L) for Captan Foliar Application to the Food Uses in
California 63
Table 3.05. Aquatic EECs (|ig/L) for Captan Foliar Application to Turf and Ornamental
Uses in California 64
Table 3.06. Aquatic EECs (|ig/L) for Captan Seed Treatment in California 64
Table 3.07. AGDISP Input parameters for almond and captan formulation 66
Table 3.08. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for
Captan with T-REX 68
Table 3.09. Upper-bound Kenega Nomogram EECs for Dietary- and Dose-based
Exposures of the Terrestrial-phase CRLF and its Prey to Captan (EECs
bracketed between foliar dissipation half lives of 10 and 35 days) 68
Table 3.10. EECs (ppm) for Indirect Effects to the Terrestrial-Phase CRLF via Effects to
Terrestrial Invertebrate Prey Items (EECs bracketed between foliar dissipation
half lives of 10 and 35 days) 69
Table 3.11. EECs for Direct Effects to the terrestrial-phase CRLF, based on captan
exposures resulting from applications to peaches (highest foliar application rate)
with 10-day foliar dissipation half-life 69
Table 4.01. Comparison of Aquatic Acute Toxicity Values for Captan and degradates.. 72
Table 4.02. Aquatic Toxicity Profile for Captan 72
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Table 4.03. Terrestrial Toxicity Profile for Captan 75
Table 4.04. Summary of selected ECOTOX papers evaluating effect of captan seed
treatment on germination and growth 78
Table 5.01. Risk Quotient values for acute and chronic exposures to Captan for Direct
Effects to the CRLF (aquatic phase) based on fish toxicity 84
Table 5.02. Risk Quotient values for exposures of parent Captan to unicellular aquatic
plants for Indirect Effects (diet of CRLF in tadpole life stage) 85
Table 5.03. Risk Quotient values for exposures of parent Captan to Aquatic Invertebrates
(Daphnid) for Indirect Effects (prey-base of CRLF) 86
Table 5.04. Risk Quotient values for exposures of parent Captan to vascular aquatic
plants for Indirect Effects (habitat of aquatic-phase CRLF) 86
Table 5.05. Acute and chronic, dietary-based RQs and dose-based RQs based on TREX
for direct effects to the terrestrial-phase CRLF (RQs bracketed between foliar
dissipation half lives of 10 and 35 days). 1 88
Table 5.06. Refined acute dose-based RQs for direct effects to the terrestrial-phase
CRLF, based on 10-day foliar dissipation half-life, calculated using T-HERPS. 1
89
Table 5.07. Summary of RQs Used to Estimate Indirect Effects to the Terrestrial-phase
CRLF via Direct Effects on Terrestrial Invertebrates as Dietary Food Items
(RQs bracketed by foliar dissipation half-lives 10-35 days) 90
Table 5.08. Summary of Acute1 and Chronic2 RQs to Estimate Indirect Effects to the
Terrestrial-phase CRLF via Direct Effects on Small Mammals as Dietary Food
Items. RQs bracketed by foliar dissipation half-lives 10-35 days 91
Table 5.09. Aquatic spatial summary results for agricultural (including ornamentals) and
orchard/vineyard land use types 94
Table 5.10. Summary of captan terrestrial action area that overlaps with CLRF habitat
range by recovery unit (RU) 97
Table 5.11. Preliminary Effects Determination Summary for Captan - Direct and Indirect
Effects to CRLF 100
Table 5.12. Preliminary Effects Determination Summary for Captan - PCEs of
Designated Critical Habitat for the CRLF 101
Table 7.0 1. Effects Determination Summary for Captan - Direct and Indirect Effects to
CRLF 119
Table 7.02. Effects Determination Summary for Captan - PCEs of Designated Critical
Habitat for the CRLF 120
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LIST OF FIGURES
Figure 1. National Captan Use from the U.S. Geological Survey (USGS), National Water
Quality Assessment Program
(http://ca.water.usgs.gov/pnsp/pesticide_use_maps/) 28
Figure 2. Captan Usage in California, PUR Data 29
Figure 3. Captan Usage in California by County (2002 - 2005) 30
Figure 4. Crops with Highest Captan Usage in California (Cal PUR Data) 30
Figure 5. Recovery Unit, Core Area, Critical Habitat, and Occurrence Designations for
CRLF (* Core areas that were historically occupied by the California red-legged
frog are not included in the map) 37
Figure 6. CRLF Reproductive Events by Month 38
Figure 7. Land cover map of captan uses in orchard/ vineyard and agricultural (including
ornamentals) areas in California 43
Figure 8. Land cover map of captan initial area of concern including the orchard/
vineyard and agricultural (including ornamentals) areas and initial stream
reaches in California 44
Figure 9. Action area map for captan including terrestrial action area (agriculture and
orchard/vineyard land uses with buffer) and aquatic action area (downstream
extent) 46
Figure 10. Conceptual Model for Pesticide Effects on Aquatic Phase of the Red-Legged
Frog 52
Figure 11. Conceptual Model for Pesticide Effects on Terrestrial Phase of Red-Legged
Frog 53
Figure 12. Conceptual Model for Pesticide Effects on Aquatic Components of Red-
Legged Frog Critical Habitat 54
Figure 13. Conceptual Model for Pesticide Effects on Terrestrial Components of Red-
Legged Frog Critical Habitat 55
Figure 14. Map showing the areas of overlap between the terrestrial and aquatic action
area and the CRLF habitat 98
Figure 15. Fish Species Sensitivity Distribution for Captan 104
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LIST OF APPENDICES (INCLUDED AS SEPARATE DOCUMENTS)
Appendix A. Ecological Effects Data for Captan
Appendix B. Citations for Seeding Rates and Planting Depths
Appendix C. Multi Active Ingredient Analysis
Appendix D. The Risk Quotient Method and Levels of Concern
Appendix E. GIS Summary for Captan Uses
Appendix F. T-REX Example Output (Multiple Applications to Peaches)
Appendix G. Bibliography of ECOTOX Open Literature
Appendix H. THPI Estimated Environmental Concentrations
Appendix I. PRZM EXAM Example Run - California Turf
Appendix J. Environmental Fate and Transport Summary
Appendix K. Fate and Ecologial Effects Bibliography
Appendix L. Terrplant EEC Output for Terrestrial Plants
ATTACHMENTS (INCLUDED AS SEPARATE DOCUMENTS)
1. Status and Life History of California Red-legged Frog
2. Baseline Status and Cumulative Effects for the California Red-legged Frog
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1. 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 captan on agricultural and non-agricultural sites. In
addition, this assessment evaluates whether these actions can be expected to result in the
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.
Captan is a registered non-systemic fungicide used to control diseases for several
agricultural crops including orchard and vineyard crops, berries, ginseng, and seeds. In
addition it is also used for non-agricultural crops including turf, ornamental grasses, and
flowers. Residential turf uses have been voluntarily cancelled and are not included in this
assessment. Captan is registered for several formulations and is applied by various
methods, including aerial, airblast, and ground applications.
Usage data suggests that areas with the largest captan usage in California, such as
Monterey County, overlap with counties having the greatest numbers of the CRLF.
According to the California Department of Pesticide Regulation's Pesticide Use
Reporting database, the largest captan usage in California is strawberries in Ventura
County averaging 102,351 pounds annually for the years 2002 to 2005. The next highest
captan usage is strawberries in Monterey, Orange, and Santa Barbara Counties.
Strawberries, almonds, prunes, grapes, non-outdoor transplants, and peaches account for
over 98% of captan use in California for the years 2002 to 2005.
Since CRLFs exist within aquatic and terrestrial habitats, exposure of the CRLF, its prey
and its habitats to captan are assessed separately for the two habitats. Aquatic exposure
models estimated high-end exposures of captan in aquatic habitats resulting from runoff
and spray drift from different uses. Peak model-estimated environmental concentrations
resulting from different captan uses range from 21.6 |ig/L for the food uses to 28.6 |ig/L
for the ornamental uses. California Department of Pesticide Regulation (CDPR) found
no detectable levels of captan at 4 sites in Santa Cruz County and 3 sites in neighboring
Monterey County on December 13, 1994; however samples were only collected on one
day and therefore conclusions cannot be drawn from these results. At the present time,
neither captan nor its degradates are included in the USGS-NAWQA program. AgDRIFT
and AGDISP models are used to estimate deposition of captan from local spray drift on
terrestrial habitats that neighbor application sites. Captan has low potential for volatility
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and air monitoring samples were below the level of detection, therefore long range
transport is unlikely.
Captan degrades rapidly and forms two major degradation products
tetrahydrophthalimide (THPI) and trichloromethylthio (TCMT). THPI is more persistent
than the parent. THPI is also degraded into a series of ring products, including
tetrahydrophthalimic acid (THPAm). Aquatic toxicity data for THPI and THPAm are
available and indicates that the degradates are about four orders of magnitude less toxic
than the parent. Tier I GENEEC screening model was used to estimate EECs and the
potential for level of concern (LOC) exceedances for aquatic organisms. Since no
exceedance was observed, THPI is not considered in this assessment.
The assessment endpoints for the CRLF include direct toxic effects on the survival,
reproduction, and growth of the CRLF itself, as well as indirect effects, such as reduction
of the prey base and/or modification of its habitat. Direct effects to the CRLF in the
aquatic habitat are based on toxicity information for freshwater fish, which are generally
used as a surrogate for aquatic-phase amphibians. In the terrestrial habitat, direct effects
are based on toxicity information for birds, which are used as a surrogate for terrestrial-
phase amphibians. Given that the CRLF's prey items and designated critical habitat
requirements in the aquatic habitat are dependant on the availability of freshwater aquatic
invertebrates and aquatic plants, toxicity information for these taxonomic groups is also
discussed. In the terrestrial habitat, indirect effects due to depletion of prey are assessed
by considering effects to terrestrial insects, small terrestrial mammals, and frogs. Indirect
effects due to modification of the terrestrial habitat are characterized by available data for
terrestrial monocots and dicots.
Risk quotients (RQs) are derived as quantitative estimates of potential high-end risk.
Acute and chronic RQs are compared to the Agency's levels of concern (LOCs) to
identify instances where captan use within the action area has the potential to adversely
affect the CRLF and its designated critical habitat via direct toxicity or indirectly based
on direct 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). When RQs for a particular type of effect are below
LOCs, the pesticide is determined to have "no effect" on the subject species. Where RQs
exceed LOCs, a potential to cause adverse effects is identified, leading to a conclusion of
"may affect." If a determination is made that use of captan 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 not likely to adversely affect" (NLAA)
from those actions that are "likely to adversely affect" (LAA) the CRLF and its critical
habitat.
For the aquatic-phase CRLF, an LAA determination was concluded for direct effects
based on LOC exceedances for acute toxic effects to fish, which is used as a surrogate for
amphibians. However, chronic LOCs are not exceeded and therefore there is no effect to
the aquatic-phase CRLF due to direct chronic toxicity. An LAA determination is made
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for indirect effects to CRLF due to reduction in fish and other frogs as food items (for
adult frogs). There is "no effect" to the aquatic-phase CRLF for indirect effects resulting
from toxicity to aquatic invertebrates, aquatic non-vascular and vascular plants as food
and habitat items. RQs were not calculated for terrestrial plants due to lack of appropriate
data. However, multiple lines of evidence suggest that captan poses minimal risk to
terrestrial plants and the effect determined to be insignificant. Based on open literature
data identified by ECOTOX database maintained by EPA/Office of Research and
Development (ORD) (U.S. EPA, 2004), captan as a seed treatment did not negatively
impact germination or growth of the evaluated plant species. Mild phytotoxic effects
were observed in highbush blueberries at an application rate of 2.5 lbs ai/acre; this
application rate is much greater than the off-field EECs based on TERRPLANT
calculations. A "may affect, not likely to adversely affect" (NLAA) determination was
made for effects to terrestrial plants. Overall, an LAA determination was concluded for
the aquatic-phase CRLF, based on direct acute effects and indirect effects to fish and
frogs as food items to adult frogs.
For the terrestrial-phase CRLF, an LAA determination was concluded for direct effects
based on acute avian toxicity data. The acute and chronic RQs, which represent an upper
bound estimate of the risk, exceed the LOC for the frog for all captan uses. Definitive
RQs could not be calculated because the avian toxicity data showed no mortality;
however, the predicted EECs are approximately three times the adjusted LD50 values for
two weight classes that are intended to be representative of juvenile and adult terrestrial-
phase CRLFs. In addition, an LAA determination was concluded for indirect effects
related to a reduction in mammals and frogs as food items. Given these direct and
indirect effects to the CRLF, modification of critical habitat is also expected for both
aquatic and terrestrial primary constituent elements (PCEs). A summary of the risk
conclusions and effects determinations for the CRLF and its critical habitat is presented
in Tables 1.1 and 1.2. Further information on the results of the effects determination is
included as part of the Risk Description in Section 5.2.
In addition, to the LAA determination for direct and indirect effects to the CRLF based
on LOC exceedances at maximum application rates, it was also demonstrated by spatial
analysis that the final action area for captan overlaps with CRLF habitats through direct
applications to target areas and runoff and spray drift to non-target areas. The terrestrial
action area is buffered by 1001 ft based on spray drift potential at the maximum single
application rate (almond) and captan toxicity to terrestrial species. This buffer was
applied to the agriculture, orchard/vineyard, and turf land use types in California.
Therefore, the terrestrial portion of the captan action area for this assessment includes all
potential agricultural, orchard/vineyard, and turf use sites and all areas that are within
1001 ft of potential captan use sites in CA. Based on this analysis, a total of 2,442 km2
(or 9%) of the CRLF range overlaps with the terrestrial portion of the captan action area
for agricultural and orchard/vineyard uses. In addition, 327 sections (34%) of established
occurrence sections of the CRLF overlap with the terrestrial portion of the captan action
area for agricultural and orchard/vineyard uses. For turf alone, a total of 1,659 km2 (or
6%) of the CRLF range overlaps with the terrestrial portion of the captan action area for
turf and 232 sections (25%) of established occurrence sections of the CRLF overlap for
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turf. Downstream extent analysis showed that for agriculture, orchard/vineyard, and turf
uses, 3,580, 1,477, and 765 kilometers were added to the stream reaches, respectively.
Some of these stream reaches overlap with CRLF habitat. Thus, spatial analysis indicates
that the uses of captan may result in CRLF exposures in aquatic and terrestrial habitats.
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Table 1.1 Effects Determination Summary for Captan - Direct and Indirect Effects to CR.LF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
Aquatic Phase (eggs, larvae, tadpoles, juveniles, and adults)
Direct Effects
Survival, growth, and reproduction
of CRLF individuals
LAA
Using freshwater fish as a surrogate, non-listed acute risk
LOCs are exceeded, chronic LOCs are not exceeded (Table
5.01).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects to
food supply (i.e., freshwater
invertebrates, non-vascular plants,
fish and frogs)
Aquatic
invertebrates
and non-
vascular plants:
No Effect
Acute freshwater invertebrate RQs do not exceed acute or
chronic LOCs (Tables 5.03). Aquatic non-vascular plant RQs
do not exceed acute LOCs (Tables 5.02).
Fish and Frogs:
LAA
Non-listed acute risk LOCs are exceeded based on the most
sensitive toxicity data for freshwater fish (Table 5.01).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
habitat, cover, and/or primary
productivity (i.e., aquatic plant
community)
No Effect
Aquatic non-vascular plant (Table 5.02) and vascular plant
(Table 5.04) RQs do not exceed acute LOCs for all captan uses.
Indirect Effects
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.
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses minimal
risk to terrestrial plants. Based on open literature data identified
by ECOTOX, captan as a seed treatment did not negatively
impact germination or growth of the evaluated plant species.
Mild phytotoxic effects were observed in highbush blueberries
at an application rate of 2.5 lbs ai/acre; this application rate is
much greater than the off-field EECs based on TERRPLANT
calculations.
Terrestrial Phase (Juveniles and adults)
Direct Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
terrestrial phase adults and juveniles
LAA
Although no mortality was observed at the highest test
concentrations in the available avian acute toxicity data, which
is used as a surrogate for terrestrial-phase amphibians,
predicted EECs are greater than highest test concentrations.
Toxicity is unknown at these exposure levels and upper-bound
RQ values exceed avian non-listed acute risk and chronic
LOCs for all uses (Table 5.05).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
prey (i.e., terrestrial invertebrates,
small terrestrial mammals and
terrestrial phase amphibians)
LAA
Non-listed acute risk and chronic LOCs are exceeded for
mammals and birds. Acute RQs for terrestrial invertebrates also
exceed the LOC for all modeled uses of captan (Tables 5.05,
5.06, and 5.07). Non-listed acute risk LOCs are exceeded
based on the most sensitive toxicity data for freshwater fish
(Table 5.01) which are a surrogate for terrestrial phase
amphibians.
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
habitat (i.e., riparian vegetation)
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses minimal
risk to terrestrial plants. Based on open literature data identified
by ECOTOX, captan as a seed treatment did not negatively
impact germination or growth of the evaluated plant species.
Mild phytotoxic effects were observed in highbush blueberries
at an application rate of 2.5 lbs ai/acre; this application rate is
much greater than the off-field EECs based on TERRPLANT
calculations.
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Table 1.2 Effects Determination Summary for Captan - PCEs of Designated Critical Habitat for
the CRLF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
Aquatic Phase PCEs
(Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)
Indirect Effects
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.
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses
minimal risk to terrestrial plants. Based on open
literature data identified by ECOTOX, captan as a
seed treatment did not negatively impact
germination or growth of the evaluated plant
species. Mild phytotoxic effects were observed in
highbush blueberries at an application rate of 2.5
lbs ai/acre; this application rate is much greater than
the off-field EECs based on TERRPLANT
calculations.
Indirect Effects
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.
NLAA
(insignificant)
Indirect Effects
Alteration of other chemical characteristics
necessary for normal growth and viability of
CRLFs and their food source.
Growth and viability
of CRLF:
Modification
Using freshwater fish as a surrogate, non-listed acute
risk LOCs are exceeded for all uses (Table 5.01).
Food source:
No Effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).Aquatic vascular plant LOCs are
not exceeded for applications of captan to all uses
(Table 5.04).
Indirect Effects
Reduction and/or modification of aquatic-
based food sources for pre-metamorphs
(e.g., algae)
No Effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).
Terrestrial Phase PCEs
(Upland Habitat and Dispersal Habitat)
Indirect Effects
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
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses
minimal risk to terrestrial plants. Based on open
literature data identified by ECOTOX, captan as a
seed treatment did not negatively impact
germination or growth of the evaluated plant
species. Mild phytotoxic effects were observed in
highbush blueberries at an application rate of 2.5
lbs ai/acre; this application rate is much greater than
the off-field EECs based on TERRPLANT
calculations.
Indirect Effects
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
NLAA
(insignificant)
Indirect Effects
Reduction and/or modification of food
sources for terrestrial phase juveniles and
Modification
Non-listed acute and chronic LOCs are exceeded for
mammals and birds for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
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Table 1.2 Effects Determination Summary for Captan - PCEs of Designated Critical Habitat for
the CRLF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
adults
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
Indirect Effects
Alteration of chemical characteristics
necessary for normal growth and viability of
juvenile and adult CRLFs and their food
source.
Modification
Non-listed acute and chronic LOCs are exceeded for
mammals and birds for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
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
15
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described above, a more complete prediction of effects to individual frogs and
potential modification to critical habitat.
2. 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
captan on a number of crops as a seed treatment and as a foliar spray on food and non-
food crops including turf and ornamentals. In addition, this assessment evaluates whether
these actions can be expected to result in the modification of the species' 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 as part of the Center for Biological
Diversity (CBD) vs. EPA etal. (Case No. 02-1580-JSW(JL)) settlement entered in the
Federal District Court for the Northern District of California on October 20, 2006.
In this endangered species assessment, direct and indirect effects to the CRLF and
potential modification to its critical habitat are evaluated in accordance with the methods
(both screening level and species-specific refinements, when appropriate) described in
the Agency's Overview Document (U.S. EPA 2004). Screening level methods include
use of standard models such as GENEEC, PRZM-EXAMS, TREX, TerrPlant, AgDrift,
and AgDisp, all of which are described at length in the Overview Document. Additional
refinements include a modification of TREX (T-HERPS) to evaluate effects on
terrestrial-phase frogs, an analysis of the usage data, and a spatial analysis. Use of such
information is consistent with the methodology described in the Overview Document
(U.S. EPA 2004), 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. EPA
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 captan are based on an action area. The action area is considered to be
16
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the area directly or indirectly affected by the federal action, as indicated by the
exceedance of Agency levels of concern (LOCs) used to evaluate direct or indirect
effects. It is acknowledged that the action area for a national-level FIFRA regulatory
decision associated with a use of captan may potentially involve numerous areas
throughout the United States and its Territories. However, for the purposes of this
assessment, attention will be focused on the section of the action area that intersects with
1) locations where CLRF is known to occur1, 2) currently occupied core areas for the
CLRF2, and 3) designated critical habitat.
As part of the "effects determination," one of the following three conclusions will be
reached regarding the potential for registration of captan at the use sites described in this
document to affect CRLF individuals and/or result in the modification of designated
CRLF critical habitat:
• "No effect";
• "May affect, but not likely to adversely affect"; or
• "May affect and likely to adversely affect".
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 the FIFRA regulatory
action regarding captan as it relates to this species and its designated critical habitat. If,
however, 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 captan.
If a determination is made that use of captan 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 captan use sites) and further evaluation of the potential impact of captan on
the PCEs is also used to determine whether modification to 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
1 As documented in the California Natural Diversity Database (CNDDB)
2 As described in the recovery plan.
17
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or the PCEs of its designated critical habitat. This information is presented as part of the
Risk Characterization in Section 5 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 captan is expected to directly impact living organisms within the action area
(defined in Section 2.7), critical habitat analysis for captan 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 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 captan 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
Captan (PC 081301, CAS Registry # 133-06-2) is a registered non-systemic fungicide
used to control diseases generally in orchard and vineyard crops, ginseng, seeds, turf and
ornamentals. Captan is registered for several formulations and is applied by various
methods, including aerial, airblast, and ground applications. A listing of all of the uses is
provided in Table 2.01.
The end result of the EPA pesticide registration process (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 captan in accordance with the approved product labels for California is
"the action" being assessed.
Although current registrations of captan allow for use nationwide, this ecological risk
assessment and effects determination addresses currently registered uses of captan in
portions of the action area that are reasonably assumed to be biologically relevant to the
CRLF and its designated critical habitat. Further discussion of the action area for the
CRLF and its critical habitat is provided in Section 2.7.
Captan is registered as a postharvest dip to apples, cherries and pears and foliar spray for
greenhouse or shade house ornamentals. It can be also incorporated into paint and
adhesives as an in-can preservative. Homeowner use of captan containing paints and
adhesives do not result in a risk concern to the Agency (U.S. EPA, 1999); therefore, they
have no effect of the CRLF. Because these uses are expected to pose negligible, if any,
exposure to terrestrial or aquatic organisms, they are not included further in this risk
assessment. In addition, black-eyed peas, cranberry, lentils, soybean, and tobacco were
18
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not included in this assessment because they are not grown in California. Low seeding
rates and pesticide application rates for bluegrass, canola/rape, chard/swiss, cotton,
cowpeas, lespedeza, peanuts, peas, sunflower, and trefoil led to expectations that
exposure level would be less than the exposure for the major crops. Therefore, these
crops were not modeled. The crops sugar beet and sugar beet (with tops) were merged
into one sugar beet crop because their modeling input data were identical.
Table 2.01 Registered I ses of ( apian
Foliar Spray. Food I so
ALMOND
BLUEBERRY DEWBERRY
MELONS
PLUM
APPLE
CANEBERRIES GINSENG
NECTARINE
PRUNE
APRICOT
CHERRY GRAPES
PEACH
RASPBERRY
(BLACK - RED)
BLACKBERRY
LOGANBERRY
Seed (rent 1110ill. lood use
PEAR
STRAWBERRY
ALFALFA
CANOLA\RAPE CUCUMBER
ONION
SQUASH (ALL OR
UNSPECIFIED)
BARLEY
CAULIFLOWER FLAX
PEANUTS
(UNSPECIFIED)
SUGAR BEET
BEANS
(TR ASS
CHARD-SWISS FORAGE/FODDER/HAY
PEAS
(UNSPECIFIED)
SUGAR BEETS
(INCL. TOPS)
BEANS - DRIED-TYPE
CLOVER KALE
PEPPER
SUNFLOWER
BEANS - SUCCULENT
(SNAP)
COLE CROPS LESPEDEZA
POTATO -
WHITE/IRISH
TOMATO
BEETS (UNSPECIFIED)
COT I ARDS MELONS -
COLLARDS CANTALOUPE
PUMPKIN
TREFOIL
BLUEGRASS
POR1SJ
(UNSPECIFIED) MELONS-MUSK
RADISH
TURNIP
BROCCOLI
CORN - FIELD MELONS - WATER
RYE
WHEAT
BRUSSELS SPROUTS
CORN - SWEET MUSTARD
SORGHUM
(UNSPECIFIED)
SPINACH
LAWN SEEDBEDS
CABBAGE
COTTON
(UNSPECIFIED)
Seed 1 real iiienl. non-food use
ALl'ALl'A
BROCCOLI CLOVER
FL.YX
UNIUN
BARLEY
BRUSSELS
SPROUTS CORN-FIELD
GRASSES GROWN
FOR SEED
RADISH
BEANS - DRIED-TYPE
CABBAGE CORN - SWEET
MELONS -
CANTALOUPE
RYE
BEANS - SUCCULENT
(SNAP)
COTTON
CANOLA\RAPE (UNSPECIFIED)
MUSTARD
TURNIP
BEETS (UNSPECIFIED)
CAULIFLOWER CUCUMBER
OATS
WHEAT
Foliar spray/ Preplant Treatment, non-food use
GOLF COURSE TURF
TURF (SOD FARMS)
AZALEAS, BEGONIAS, CHRYSANTHEUM, ROSES
DICHONDRA GRASSES
CAMELLIAS, CARNATIONS ORNAMENTAL GRASSES IN NON-PASTURED AREAS
2.2.1 Degradates
Captan degrades rapidly and forms two major degradation products
tetrahydrophthalimide (THPI) and tetrahydrophthalimic acid (THPAm). THPI is also
degraded into a series of ring products, including tetrahydrophthalimic acid (THPAm).
Aquatic toxicity data for THPI and THPAm is available and indicates that the degradates
are about four orders of magnitude less toxic than the parent. However, THPI is more
persistent than the parent. Tier I screening tool (GENEEC model) was used to estimate
EECs, and evaluate the potential for LOC exceedances for aquatic organisms. Since no
19
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exceedance was observed, THPI is not considered further in this assessment (Appendix
H).
2.2.2 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).
Captan is a component of multiple ingredient formulations in various products. These
formulations may include lindane, malathion, carbaryl, methochlor, metalaxyl, carboxin,
pentachloronitrobenzene (PCNB), and diazinon. A limit dose test was done for several
captan formulations but no definitive product LD50 values resulted with associated 95%
Confidence Intervals (CIs). Several of the studies resulted in LD50 values greater than the
dose tested. Analysis of the available acute oral mammalian LD50 data for multiple active
ingredient products relative to the single active ingredient, captan, is provided in
Appendix C.
As discussed in USEPA (2000) a quantitative component-based evaluation of mixture
toxicity requires data of appropriate quality for each component of a mixture. In this
mixture evaluation an LD50 with associated 95% CI is needed for the formulated
product. The same quality of data is also required for each component of the mixture.
Given that the formulated products for captan do not have LD50 data available it is not
possible to undertake a quantitative or qualitative analysis for potential interactive
effects. However, because the active ingredients are not expected to have similar
mechanisms of action, metabolites, or toxicokinetic behavior, it is reasonable to
conclude that an assumption of dose-addition would be inappropriate. Consequently,
an assessment based on the toxicity of captan is the only scientifically reasonable
approach that employs the available data to address the potential acute risks of the
formulated products.
2.3 Previous Assessments
Captan was first registered as a pesticide under the Federal Insecticide, Fungicide and
Rodenticide Act in 1951 for the control of fungal diseases of fruit crops. Prior to 1980,
there were many use-patterns registered and tolerances established for this broad
spectrum fungicide. Currently, there are 159 registered products (including 17 State and
Local Needs) containing captan.
20
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The Captan Reregi strati on Eligibility Decision (RED) document was completed in
September 1999. The Agency assessment determined that the data were sufficient to
support reregi strati on of products containing captan, except for those with uses on turf
and aerially-applied wettable powder formulations. Products applied to turf at sod farms
or golf courses were eligible for reregistration; uses at all other turf sites were voluntarily
cancelled. Wettable powder formulations that are applied aerially are eligible for
reregistration, provided either: 1) the products are packaged in water soluble packaging;
or 2) the application rates are reduced to a level that is no higher than 1.2 lb ai/A.
On November 1, 2004, an amendment to the RED was issued with the following
ecological risk mitigation included:
> The dichondra ornamental grass, golf course turf, and turf sod farm use rates are
reduced from a single application rate of 43 pounds active ingredient per acre to
4.3 pounds active ingredient per acre. Two applications per year are allowed for a
seasonal maximum application rate of 8.6 pounds of active ingredient per acre.
> Spray Drift language has been modified. An additional requirement for a
maximum nozzle height of 4 feet above the crop canopy with ground boom
application has been added.
> Application restrictions for products used on turf have been expanded to specify a
prohibition on applications to turf in residential sites, apartment buildings,
daycare centers, playgrounds, sports fields, or other residential areas.
2.4 Stressor Source and Distribution
2.4.1 Environmental Fate Assessment
Selected physical, chemical, and environmental fate properties of captan are listed in
Table 2.02. Captan is a non-volatile (8 x 10"8 mm Hg at 25°C) and low solubility (3.3
mg/L at 25°C) in water. Captan has a relatively short half-life (ti/2=l to 10 days) in soil
and aquatic environments. Abiotic hydrolysis and aerobic metabolism appear to be the
major routes of captan dissipation in the environment. In both soil and water, the sulfur-
nitrogen bond cleaves, thus separating the trichloromethylthio (TCMT) and
tetrahydrophthalamide (THPI) moieties of the molecule. The TCMT moiety degrades by
aerobic soil metabolism to form CO2, thiophosgene, and inorganic sulfur and chlorine.
Dissipation of thiophosgene is expected to be controlled by volatilization (est. vapor
pressure=29.7 mm Hg and estimated Henry's Law Constant of 0.00586 atm*M"3 mole"1).
It should be noted that thiophosgene was not detected as a volatile component in any of
the submitted laboratory studies for captan.
21
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Table 2.02 Selected Physical and Chemical Properties of Captan
PiininK'k'r
Value iind I nil
Sources
Chemical Structure
O
/y(
1 N-S^ /I
X/W' /CX
\ CI CI
Chemical Name
Captan
3a,4,7,7a-tetrahydro-2-[(trichloro
methyl)thio] - lH-isoindole-1,3 (2H)-dione
133-06-2
081301
Smiles notation
CAS Number
PC Code
Molecular Formula
c9h8ci3no2s
Product Chemistry
Molecular Weight
300.57 gram/mol
Product Chemistry
Appearance
Solid
Product Chemistry
Color
White
Product Chemistry
Odor
No odor
Product Chemistry
Melting Point
178°C (pure compound);158-
170°C(technical grade, 90-95%
pure)
Product Chemistry
Vapor pressure
8 x 10-8 mm Hg at 25°C
Product Chemistry
Water Solubility (pH 7, 25°C)
3.3 mg/L at 25°C
Product Chemistry
Henry's law constant (KH)
9.6E-10 Atm.M3 Mol"1
Estimated
Octanol/Water Partition
Coefficient logKow
2.79
EPI SUITE
Hydrolysis (pH 5, 7, and 9)
0.8, 0.25, 0.006 days
MRIDs 40208101,41176301,
00096974
Soil Kd
3-8 ml/g
MRIDs 4065801,4368911
Aerobic Aquatic Metabolism
<1.0 days
MRIDs 40114502
Aerobic soil half-life
<1.00 days
MRID 40658007
Anaerobic soil half-life
1.85 days
MRID 00098881
Photolysis half-life (pH 7)
0.42 days
MRIDs 40208102, 41176301
THPI is rapidly degraded by aerobic soil metabolism to a series of ring-containing
products (including THPAm) and ultimately CO2 (MRID 38689-02). Freundlich Kd
values for THPI ranged from 0.04-0.23 L/kg in six soils (MRID 438689-11). THPI is
expected to move with surface water runoff or leaching into the soil (Table 2.03).
Evidence indicates that residues of THPI may be present in soil several weeks following
captan application.
22
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Table 2.03 Knvironiiienlal lale properties lor (lie riegrariale. I'll PI
PsirsiimMcrs
\'sillies siihI I nil
Sources
Chemical Structure
0
({
cc
>JH
(
O
Chemical Name 1,2,3,6-Tetrahydrophthalimide
Soil Partition Coefficient (Kd)
0.04 - 0.23 ml/g
MRID 438689-11
Molecular Weight
151.6
Product Chemistry
Solubility (25° C) x 100
lOppm
Estimated
Aerobic Soil Metabolism Ti/2
6-19.5 days
MRID 3868902
Aerobic Aquatic Metabolism
Half-Life
21 days
MRID 00098881
Captan photodegradation on soil also occurs, but is secondary to hydrolysis and aerobic
soil metabolism. Kd values of 3.0 to 8.0 ml/g indicate that captan is generally expected to
have moderate mobility in soil. In terrestrial field studies, however, captan was shown to
be relatively immobile to slightly mobile at 6 different field sites.
Captan has a low potential for bioaccumulation in fish due to rapid hydrolysis in aquatic
environments and low log Kow (2.79) (Table 2.02). Captan residues had fish
bioconcentration factors (BCF) of 102X, 126X, and 113X for edible, non-edible, and
whole fish tissue, respectively. After a 14-day depuration period, captan residues in
edible tissue, non-edible tissue, and whole fish declined by 94%, 96%, and 95%,
respectively.
In terrestrial field dissipation study, parent captan dissipates with half-lives of 2.5 to 24
days and was relatively immobile to slightly mobile at six sites. The maximum depth at
which captan was detected was 6-12 inches. The degradate THPI was detected at all sites
and declined to less than detectable (0.01 ppm) levels between 14 and 184 days after the
final captan treatment. THPI was not detected below 12 inches of soil profiles.
2.4.2 Environmental Transport Assessment
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 ecosystems. The magnitude of pesticide transport via secondary drift
depends on the pesticide's ability to be mobilized into air and its eventual removal
through wet and dry deposition of gases/particles and photochemical reactions in the
atmosphere.
A number of studies have documented atmospheric transport and redeposition of
pesticides from the Central Valley to the Sierra Nevada mountains (Fellers et al., 2004,
Sparling et al., 2001, LeNoir et al., 1999, and McConnell et al., 1998). Prevailing winds
blow across the Central Valley eastward to the Sierra Nevada mountains, transporting
23
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airborne industrial and agricultural pollutants into Sierra Nevada ecosystems (Fellers et
al., 2004, LeNoir et al., 1999, and McConnell et al., 1998). Therefore, physicochemical
properties of the pesticide that describe its potential to enter the air from water or soil
(e.g., Henry's Law constant and vapor pressure), pesticide use, modeled estimated
concentrations in water and air, and available air monitoring data from the Central Valley
and the Sierra Nevadas are considered in evaluating the potential for atmospheric
transport of captan to habitat for the CRLF.
Captan has low potential for volatility and measured concentrations were below the level
of detection in air monitoring samples, therefore long range transport is unlikely.
AgDRIFT and AGDISP are used to estimate deposition of captan from local spray drift
on terrestrial habitats that neighbor application sites. In general, deposition of drifting
pesticides is expected to be greatest close to the site of application.
2.4.3 Mechanism of Action
Captan is a non-systemic, phthalimide fungicide used to control fungal diseases of many
fruit, ornamental, and vegetable crops. The mode of action of captan is inhibition of
normal cell division of a broad spectrum of microorganisms and fungi. Captan is known
as a stressor to aquatic organisms (fish, invertebrates, mollusks, amphibians, and benthic
dwellers) and to lesser degree mammals by limiting and ultimately inhibiting the process
of oxidative phosphorylation, which is needed for respiration in aquatic organisms as
well as terrestrial organisms and humans (Cremlyn, 1996; Johnson and Finaly, 1980).
2.4.4 Use Characterization
Analysis of labeled use information is the critical first step in evaluating the federal
action. The current label for captan 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. Captan is used as a foliar spray
on strawberry, ginseng, and several orchard and vineyard crops (Table 2.04). Captan is
also used as a foliar, dip and seedbed treatment to turf and ornamental grasses and
flowers (Table 2.05). It is also used as a seed treatment for food and non-food uses
(Table 2.06).
Estimations were made for the number of applications per year for ornamental grasses.
Ornamental grasses in non-pasture areas are treated for several diseases and can be
sprayed beginning at spring and applied throughout the season. The maximum single
application rate for ornamental grasses is 4.3 lb a.i./A. The maximum annual application
rate and number of applications were not specified on the Drexel Chemical Company
labels; therefore it was estimated for this assessment that the season for grasses would
last approximately seven months in California. The maximum of 26 annual applications
with 7-day intervals was modeled (Table 2.05).
24
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Application to ornamental flowers was not assessed because environmental exposure is
expected to be lower than that due to ornamental grass and turf uses. In addition, many of
these flowers are treated in greenhouses or shade houses which results in minimal
environmental exposure (Section 3.1).
T:ihlc2.04 Csiplsin
l'"»lisir Application lo l-'oori I scs
CROP
Max.
Max. # of
Min. Inlcnal
Max. Annual I so
Application
Applications
IJeUu'en Apps.
Kale (Ihs ai)
Kale (Ihs ai/A)
(da\s)
STRAWBERRY
3.0
8
7
24.00
GINSENG
2.0
S
"
16.00
Orchard Crops
ALMOND
4.5
4
"
20.00
APPLE
4.0
S
5
32.00
APRICOT
2.5
5
5
12.50
CHERRY
2.0
7
7
14.00
NECTARINE
4.0
6
3
24.00
PEACH
4.0
8
3
32.00
PLUM/ PRUNE
3.0
9
7
27.00
\ iiii'Mird Crops
BLACKBERRY/
2.0
5
10
10.00
CANEBERRY/
RASPERRY/
DEWBERRY
3.13
3
10
9.39
LOGANBERRY
1.956
5
3
9.78
BLUEBERRY
2.5
14
7
35.00
GRAPES
2.0
6
10
12.00
25
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Table 2.05. Application Kates lor I so of ( apian on Ornamentals
I so
Disosiso
Applicsilion
r:ilo
(Ih a.i./A)1
N iiin hor of
Applications
per year
Interval
Instructions
Azaleas, Begonias
(tuberous),
Chrysanthemum
Damping-
off of
cuttings
2
1
Dip cuttings/ tubers
before bedding
Gladiolus (Corms)
Corm rot
and decay,
damping-off
2.5-7.5
1
Dip corms before
planting
Azaleas
Petal Blight
1
Approximately
5
7
Spray flowers/ soil
through bloom (~5
weeks)
Camellias
Petal Blight
0.5
Approximately
12
7
Spray soil through
bloom (~3 months)
Chrysanthemum,
Roses, Carnations
Botrytis
flower
blight,
Septoria leaf
spot, black
spot,
Alternaria
leaf spot,
rust
1
Approximately
26 for roses 2
7
Spray flowers at
first sign of disease
(roses- all year,
mums approx. 7 -
10 weeks)
Grasses
(Ornamental in
non-pastured areas
only)
Brown
patch,
brown spot,
damping off,
leaf spot,
melting out,
seedling
blight
4.36
Approximately
26 2
7
Start at spring
growth and apply
throughout the
season
Grasses (lawn
seedbeds)
Damping
off, other
soil borne
diseases
6.53
1
Cultivate in top 3-4
inches of soil before
planting
Soil and
Greenhouse bench
treatment
Damping-
off, root rot
6.53
1
Preplant treatment
on seedlings or
transplants of roses
(or other shrubs,
trees, flowers) and
lawn seedbeds.
Cultivate in top 3-4
inches of soil before
planting
Turf (Golf
Course), Sod
Farms, Dichondra
White mold,
damping off,
leaf spot
4.3 lb ai/A
2
7
Max App Rate is
8.6 lb ai/A
1 Assumes 100 gallons is used on one acre as stated on Captec label (EPA Reg. 066330-239)
2
Label does not indicate a maximum number of applications or annual rate; therefore, the maximum of 26
applications was chosen
26
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Tsihle 2.06. Application Rules lor Seed Tresilmenl using Csiplsin
Crop
Ciipliin
Application
U.ile (Ills.
Ai/tttl)
Smling
U.ile 1
(Ills/ill'IV)
Cum cried
( iipliin
Application
(II) ii.i./A):
I'liinling Depth (in)
I scd in Model
ALFALFA
0.2578
35
0.09023
1.00
BARLEY
0.0938
100
0.0938
1.00
BEETS (UNSPECIFIED)
0.375
3
0.01125
1.00
BROCCOLI
0.0656
1.5
0.000984
1.00
BRUSSELS SPROUTS
0.0656
1
0.000656
1.00
CABBAGE
0.0656
1.5
0.000984
1.00
CAULIFLOWER
0.0656
1.5
0.000984
1.00
CLOVER
0.2578
30
0.07734
0.50
COLLARDS
0.0293
4
0.001172
1.00
CUCUMBER
0.0969
3
0.002907
1.00
FLAX
0.1219
50
0.06095
1.00
GRASS
FORAGE/FODDER/HAY
0.2578
435
1.12143
1.00
KALE
0.0293
5
0.001465
1.00
MELONS - CANTALOUPE
0.0969
4
0.003876
1.00
MELONS - MUSK
0.0625
4
0.0025
1.00
MELONS - WATER
0.0625
2.5
0.0015625
1.00
MUSTARD
0.0625
20
0.0125
1.00
OATS
0.125
96
0.12
1.00
ONION
0.7875
4
0.0315
1.00
PEPPERS
0.0938
2
0.001876
1.00
POTATO - WHITE/IRISH
0.0513
2,800
1.4364
1.00
RADISH
0.0656
25
0.0164
1.00
RYE
0.0938
150
0.1407
1.00
SPINACH
0.2031
25
0.050775
1.00
SQUASH (ALL OR
UNSPECIFIED)
0.0625
4
0.0025
1.00
TOMATO
0.0546
0.5
0.000273
1.00
TURNIP
0.0906
3
0.002718
1.00
WHEAT
0.125
135
0.16875
1.00
1 References for the seeding rate information can be found in Appendix B.
2 The values in the Captan Maximum Application Rate (lbs a.i. /A) column are the product of the Captan
Application Rate (lb a.i. /cwt) multiplied by the Seeding Rate (lb/A).
27
-------
A national map (Figure 1) showing the estimated poundage of captan uses across the
United States is provided below. The map was downloaded from the U.S. Geological
Survey (USGS), National Water Quality Assessment (NAWQA) Program
(http://ca.water.usgs.gov/pnsp/pesticide_use_maps/). On a national level the highest uses
are apples, strawberries, peaches, and blueberries. For California, captan use is heaviest
in the Central Valley and coastal areas.
CAPTAN - fungicide
2002 estimated annual agricultural use
Crops
Total
Percent
pounds applied
national use
apples
1741887
61.01
strawberries
384164
13.46
peaches
261361
9.15
blueberries
121060
4.24
almonds
85949
3.01
cherries
79340
2.78
raspberries
65829
2.31
plums and prunes
65390
2.29
grapes
43766
1.53
blackberries
2804
0.10
Average annual use of
active ingredient
(pounds par square mile of agricultural
land in county)
CH no estimated use
~ 0.001 to 0.013
~ 0.014 to 0.057
~ 0.058 to 0.205
~ 0.206 to 0.875
¦ >=0.876
Figure 1. National Captan Use from the U.S. Geological Survey (USGS), National Water Quality
Assessment Program (http://ca.water.usgs.gov/pnsp/pesticide_use_maps/)
The Agency's Biological and Economic Analysis Division (BEAD) provides an analysis
of both national- and county-level usage information (Captan LUIS report, 2007) using
state-level usage data obtained from USDA-NASS3, 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) database4 . 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 captan by county in this
California-specific assessment were generated using CDPR PUR data. Usage data are
3 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.
4 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/punnain.htm.
28
-------
averaged together over the years 2002 to 2005 to calculate average annual usage statistics
by county and crop for captan, including pounds of active ingredient applied and base
acres treated. California State law requires that most pesticide application be reported to
the state and made available to the public. According to the PUR database, the average
annual number of pounds applied during 2002 - 2005 were 426,171 pounds of captan
(Figure 2). The largest captan usage at the county-level is strawberries in Ventura
County averaging 102,351 pounds annually during the four year period. The next highest
captan crop usage by county is strawberries in Monterey, Orange, and Santa Barbara
Counties (Figure 3). Strawberries, almonds, prunes, grapes, non-outdoor transplants, and
peaches account for over 98% of captan use in California for the years 2002 to 2005
(Figure 4). A summary of captan usage for all use sites, including both agricultural and
non-agricultural, is provided below in Table 2.07. The use of captan was reported in 45
counties during this four year period. The annual average pounds for each crop were
summed for each county. The annual average application rate was presented as a range
for the counties analyzed.
600,000
500,000
400,000
| 300,000
3
O
Q.
200,000
100,000
0
Figure 2. Captan Usage in California, PUR Data
2002 2003 2004 2005
29
-------
tfl
~o
c
3
o
a.
120000
100000
80000
60000
40000
20000
1
III
Mil
Mini
H
£
W
>
O
£
Q
&
I
e
-
o
!X
X
w
H
J
§
w
Q
00
pc!
W
>
£
w
w
o
§
CO
O
J
C
H
Figure 3. Captan Usage in California by County (2002 - 2005)
N-OUTDR
^TRANSPLANTS
1%
PEACH
1%
PRUNE
14%
OTHER
^2%
ALMOND
19%
STRAWBERRY
59%
Figure 4. Crops with Highest Captan Usage in California (Cal PUR Data)
30
-------
Tsihlc 2.07. (';ilir»rni;i Coiinlv
Level PI U lor (nplnn
Crop
Tolill
Riiniic of
A\cr;iiic
A\it;i*£c Miiximum
(# counlies
A\cr;iiic
A\cr;i»c
Application R;i(c
Application R;i(c
included in
Anniiiil
Application
(II) ii.i./A)
(II) ii.i./.\)
iin;ihsis)
Pounds
Applied
(su in mod for
nil connlies)
Kiilc lor iill
con n lies
(II) ii.i./A)
Strawberry
249,768
0.7-3.8
2.6
7.0
(20 Counties)
Almond
82,550
0.1-3.3
3.6
6.1
(15 counties)
Prune
59,692
2.2-2.9
3.1
6.8
(14 Counties)
Grape
15,186
1.0-3.4
3.1
5.0
(10 Counties)
Non-Outdoor
4,308
0.3-2.6
2.1
4.4
Transplants
(12 Counties)
Peach
4,145
0.2-11.0
3.5
5.3
(16 Counties)
Nectarine
2,193
1.0-2.9
3.5
3.5
(9 Counties)
Plum
1,875
1.4-3.1
2.8
4.6
(11 Counties)
Apple
933
0.2-3.9
2.2
2.2
(16 Counties)
Non-Outdoor
567
0.2-6.7
6.1
6.6
Flower
(9 Counties)
Landscape
423
N/A
N/A
N/A
Maintenance
(16 Counties)
Sudan grass
301
N/A
N/A
N/A
(3 Counties)
Grape, Wine
219
0.1-1.7
1.1
1.1
(11 Counties)
Cherry
168
0.9-3.0
2.2
2.2
(9 Counties)
Blueberry
(5 Counties)
167
0.7-2.0
2.1
2.1
Corn (Forage-
107
<0.1-0.1
0.1
0.1
Fodder)
(11 Counties)
Unknown
105
2.9
2.9
2.9
(3 Counties)
Non-Outdoor Plants
103
<0.1-4.9
2.2
3.2
in Containers
(14 Counties)
Non-Greenhouse
96
0.6-16.8
10.7
11.5
Flower
(10 Counties)
Apricot
44
0.9-2.4
1.7
2.0
(4 Counties)
Non-Greenhouse
26
<0.01 -7.9
5.5
5.5
31
-------
Tsihlc 2.07. (';ilir»rni;i ( oiinlv
Level PI U lor (nplnn
Crop
Tolill
Riiniic of
A\cr;iiic
A\it;i*£c Miiximum
(# counlies
A\cr;iiic
A\cr;i»c
Application R;i(c
Application R;i(c
included in
Anniiiil
Application
(II) ii.i./A)
(II) ;i.i./.\)
iin;ihsis)
Pounds
Applied
(su in mod for
nil connlies)
Kiilc lor iill
con n lies
(II) ii.i./A)
Plants in Containers
(13 Counties)
Cotton
26
<0.1-0.2
0.1
0.1
(5 Counties)
Broccoli
19
1.2
2.0
2.0
(1 County)
Non-Greenhouse
16
<0.1-4.7
2.5
2.5
Transplants
(7 County)
Safflower
14
<0.1
<0.1
<0.1
(3 Counties)
Uncultivated
13
1.0
1.4
1.4
Non-agriculture
(1 County)
Oats
12
N/A
N/A
N/A
(1 County)
Cantaloupe
(2 Counties)
6.6
<0.1
0.1
0.1
Corn (Human
6.6
<0.1
<0.1
<0.1
Consumption)
(4 Counties)
Raspberry
(2 Counties)
3.7
0.6-2.0
3.0
3.0
Squash
(2 Counties)
2.5
0.5
0.5
0.5
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
32
-------
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 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
(Figure 5). 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 2.08 and
shown in Figure 5.
33
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Core Areas
USFWS has designated 35 core areas across the eight recovery units to focus their
recovery efforts for the CRLF (see Figure 2.05). Table 2.08 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.
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 location information is evaluated within the broader context of
recovery units. For example, if no labeled uses of captan 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 2.08 (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.
34
-------
Tsihlc 2.08. Ciilirorniii Kcd-lcggcd l-'rog Recovery I nils with Overlapping Core
Are:is;md Designated Critical 1 l:ihil:il
( urrenlh
Ueco\er\ I nil 1
(ligure 2.;i)
( ore Areas (l-igure 2.;i)
Critical llahilal
I nils
Occupied
(pos(-iy85)
4
Historically
Occupied 4
Cottonwood Creek (partial)
(8)
Feather River (1)
BUT-1A-B
Yuba River-S. Fork Feather
YUB-1
Sierra Nevada
River (2)
Foothills and Central
--
NEV-16
Valley (1)
Traverse Creek/Middle Fork
(eastern boundary is
American River/Rubicon (3)
the 1,500m elevation
Consumnes River (4)
ELD-1
line)
S. Fork Calaveras River (5)
--
Tuolumne River (6)
--
Piney Creek (7)
--
East San Francisco Bay
(partial)(16)
Cottonwood Creek (8)
--
Putah Creek-Cache Creek (9)
--
North Coast Range
Foothills and
Western Sacramento
River Valley (2)
Jameson Canyon - Lower
Napa Valley (partial) (15)
--
Belvedere Lagoon (partial)
(14)
--
Pt. Reyes Peninsula (partial)
(13)
--
Putah Creek-Cache Creek
(partial) (9)
Lake Berryessa Tributaries
(10)
NAP-1
North Coast and
Upper Sonoma Creek (11)
--
North San Francisco
Petaluma Creek-Sonoma
Bay (3)
Creek (12)
Pt. Reyes Peninsula (13)
MRN-1, MRN-2
Belvedere Lagoon (14)
~
Jameson Canyon-Lower
Napa River (15)
SOL-1
--
CCS-1A6
East San Francisco Bay
ALA-1A, ALA-
South and East San
(partial) (16)
IB, STC-1B
Francisco Bay (4)
--
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
MNT-2
(20)
Estero Bay (22)
~
35
-------
--
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
--
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.
36
-------
Recovery Units
Sierra Nevada Foothills and Central Valley
North Coast Range Foothills and Western
Sacramento River Valley
North Coast and North San Francisco Bay
South and East San Francisco Bay
Central Coast
Diablo Range and Salinas Valley
Northern Transverse Ranges and Tehachapi
Mountains
Southern Transverse and Peninsular Ranges
Legend
|__| Recovery Unit Boundaries
Currently Occupied Core Areas
| Critical Habitat
I CNDDB Occurence Sections
County Boundaries
180 Miles
Figure 5. Recovery Unit, Core Area, Critical Habitat,
that were historically occupied by the California red-
Core Areas
1. Feather River
2. Yuba River- S. Fork Feather River
3. Traverse Creek/ Middle Fork/ American R. Rubicon
4. Cosumnes River
5. South Fork Calaveras River*
6. Tuolumne River*
7. Piney Creek*
8. Cottonwood Creek
9. Putah Creek - Cache Creek*
10. Lake Berryessa Tributaries
11. Upper Sonoma Creek
12. Petaluma Creek - Sonoma Creek
13. Pt. Reyes Peninsula
14. Belvedere Lagoon
15. Jameson Canyon - Lower Napa River
16. East San Francisco Bay
17. Santa Clara Valley
18. South San Francisco Bay
19. Watsonville Slough-Elkhorn Slough
20. Carmel River - Santa Lucia
21. Gablan Range
and Occurrence Designations for CRLF (* Core areas
legged frog are not included in the map)
22. Estero Bay
23. Arroyo Grange River
24. Santa Maria River - Santa Ynez River
25. Sisquoc River
26. Ventura River - Santa Clara River
27. Santa Monica Bay - Venura Coastal Streams
28. Estrella River
29. San Gabriel Mountain*
30. Forks of the Mojave*
31. Santa Ana Mountain*
32. Santa Rosa Plateau
33. San Luis Ray*
34. Sweetwater*
3 5. Laguna Mountain*
37
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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 6 depicts CRLF annual reproductive timing.
Figure 6. CR
^F 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 and entrap suspended algae (Seale and Beckvar, 1980)
38
-------
via mouthparts designed for effective grazing of periphyton (Wassersug, 1984,
Kupferberg et al.\ 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 of the riparian habitat depends on moisture, composition of the plant
39
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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 2.08.
'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
40
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• Dispersal habitat.
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 captan 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).
41
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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 captan is expected to directly impact living
organisms within the action area, critical habitat analysis for captan 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 captan 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 the product of consideration of the types of effects that captan
may be expected to have on the environment, the exposure levels to captan that are
associated with those effects, and the best available information concerning the use of
captan 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 captan. An analysis of labeled uses and review of available product labels was
completed. Foliar and seed applications of captan to the food and non-food uses listed in
Table 2.01 were assessed.
After a determination of which uses will be assessed, an evaluation of the potential
"footprint" of the use pattern should be determined. This "footprint" represents the initial
area of concern and is typically based on available land cover data for the state of
California. The use map shows the extent of orchard/vineyard, agricultural (including
ornamentals), and turf land cover which represent the labeled uses for captan in
California (Figure 7). The initial area of concern is defined as the agriculture, turf and
orchard/vineyard land cover types and the initial stream reaches (Figure 8).
42
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Captan Use Map
Legend
Turf Use
Orchard^ Vineyard Use
Agriculture Use
| | County Boundaries
240
^¦Kilometers
Compiled from California County boundaries (ESRI, 2002), M a p c reated by US E rw iro nmental P rote ctio n A gen cy, Offi c e
USQA National Agriculture Statistical Service (MASS 2002) of Pesticides Programs, Environmental Fate and Effects Division.
Gap Analysis Program Orchard/ Vineyard Land cower (GAP) September, 2007. Projection: Albers Equal Area Conic USGS,
National Land Ctwer Database (NLCD) (MRLC, 2001) North American Datum of 1983 (NAD1983!
Figure 7. Land cover map of captan uses in orchard/ vineyard, agricultural (including
ornamentals), and turf areas in California
43
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Captan - Initial Area of Concern
egend
— Initial Streams
Turf Use
Orchard/Virieyard Use
Agriculture Use
~1 County Boundaries
120
120 Kilometers
Compiled from California County boundaries (ESRI, 2002), M a p c reated by US E rw iro nmental P rote ctio n A gen cy, Offi c e
USQA National Agriculture Statistical Service (MASS 2002) of Pesticides Programs, Environmental Fate and Effects Division.
GapAnat/sis Program Orchard/ Vine/ard Land cower (GAP) September, 2007. Projection: Alters Equal Area Conic USGS,
National Land Ctwer Database (NLCD) (MRLC, 2001) North American Datum of 1983 (NAD1983!
Figure 8. Land cover map of captan initial area of concern including the orchard/
vineyard, agricultural (including ornamentals), and turf areas and initial stream reaches in
California.
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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 will define 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 captan to determine which routes of
transport are likely to have an impact on the CRLF.
LOC exceedances are used to describe how far effects may be seen from the initial area
of concern. Factors considered include: spray drift and downstream run-off This
information is incorporated into GIS and a map of the action area is created.
The AgDRIFT model (Version 2.01) is used to define how far from the initial area of
concern an effect to a given terrestrial species may be expected. The spray drift analysis
for captan using the most sensitive terrestrial toxicity endpoint {i.e., terrestrial
invertebrates) suggests that the distance for potential effects from the treated area of
concern is not within the range of the AgDrift model {i.e., 1000 feet). Subsequently, the
AgDISP model (Version 8.15) with the Gaussian extension (used for longer range
transport because the limits of the regular AgDISP model were exceeded) was used to
define this distance. The AgDISP model was run in ground mode using default settings
(except for wind speed at 10 mph and release height at 4 feet). Using the Gaussian
extension, a maximum spray drift distance of 8,740 feet was derived. Further detail on
the spray drift analysis is provided in Section 3.2.3. Further detail on defining the
terrestrial action area is provided in Section 5.1.4.2.
In addition to the buffered area from the spray drift analysis, the final action area also
considers the downstream extent of captan that exceeds the LOC (discussed in Section
3.2.4). The downstream area of the action area for captan is based on the endangered
species LOCs for freshwater fish. Further detail on defining the aquatic action area is
provided in Section 5.1.4.1. The action area for captan, including the full extent (based on
the listed species LOCs) and the portion of the action area that is relevant for the CRLF is
presented graphically in Figure 9. Further detail on defining the final action area is
provided in Section 5.1.4.3.
Subsequent to defining the action area, an evaluation of usage information was conducted
to determine the area where use of captan may impact the CRLF. This analysis is used to
characterize where predicted exposures are most likely to occur, but does not preclude
use in other portions of the action area. Usage data suggests that areas of the largest
captan usage in California, such as use on strawberries in Monterey, overlap with
counties having the greatest numbers of the CRLF. The greatest numbers of the CRLF
occur in Monterey, San Luis Obispo, and Santa Barbara counties (USFWS, 1996) in
California.
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Captan - Action Area
Legend
Initial and Downstream Stream Segments
Terrestrial Action Area (with buffer) V
County Boundaries
100
200 Kilometers
Compiled from California County boundaries (ESRI, 2002), M a p c reated by US E rw iro nmental P rote ctio n A gen cy, Offi c e
USQA National Agriculture Statistical Service (MASS 2002) of Pesticides Programs, Environmental Fate and Effects Division.
GapAnai/sis Program Orchard/ Vine/ard Land cower (GAP) Septerrber, 2007. Projection: Albers Equal Area Conic USGS,
National Land Ctwer Database (NLCD) (MRLC, 2001) North American Datum of 1983 (NAD1983!
Figure 9. Action area map for captan including terrestrial action area (agriculture, turf,
and orchard/vineyard land uses with buffer) and aquatic action area (downstream extent)
46
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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."5 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 captan
(e.g., runoff, spray drift, etc.), and the routes by which ecological receptors are exposed
to captan-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 and/or modification of its 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 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 captan is provided in Table 2.09.
Table 2.09. Summary of Assessment Kudpoints and Measures of Ideological KITects
lor Direct and Indirect K fleets of Captan on the California Ked-legged l-"rog
Assessment Endpoint
Measures of Ecological Effects6
Aquatic Phase
(eggs, larvae, tadpoles, juveniles, and adults)&
1. Survival, growth, and reproduction of CRLF
individuals via direct effects on aquatic phases
la. Brown Trout acute LC50
lc. Fathead Minnow chronic NOAEC
2. Survival, growth, and reproduction of CRLF
individuals via effects to food supply (i.e.,
freshwater invertebrates, non-vascular plants)
2a. Brown Trout acute LC50
2b. Fathead minnow chronic NOAEC
2c. Water flea acute EC50
2d. Water flea chronic NOAEC
2e. Non-vascular plant (freshwater algae) acute
EC50
3. Survival, growth, and reproduction of CRLF
individuals via ndirect effects on habitat, cover,
3a. Vascular plant acute EC50 (duckweed)
3b. Non-vascular plant acute EC50 (freshwater
5 From U.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.
6 All registrant-submitted and open literature toxicity data reviewed for this assessment are included in
Appendix A.
47
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and/or primary productivity (i.e., aquatic plant
community)
algae)
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. Terrestrial Plants (qualitative data)
4b. Terrestrial Plants (qualitative data)7
Terrestrial Phase
(Juveniles and adults)
5. Survival, growth, and reproduction of CRLF
individuals via direct effects on terrestrial phase
adults and juveniles
5a. Mallard Duck acute LD50 b
5b. Mallard Duck/ Northern bobwhite quail chronic
NOAECb
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. Honey bee acute contact LD50
6b. Rat acute LD50
6b. Rat chronic NOAEC
6b. Mallard duck acute LD50b
6b. Bobwhite quail chronic NOAEC b
7. Survival, growth, and reproduction of CRLF
individuals via indirect effects on habitat (i.e.,
riparian vegetation)
7a. Terrestrial Plants (qualitative data)
7b. Terrestrial Plants (qualitative data)
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 that exposure pathways on land.
b Birds are used as surrogates for terrestrial phase amphibians.
0 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 captan 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 captan effects data are
available.
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.
7 The available information indicates that the California red-legged frog does not have any obligate
relationships.
48
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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 captan on critical habitat of the CRLF
are described in Table 2.10. 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).
49
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Tsihle 2.10. Siiiiiniiirv of Assessment Kmlpoinls sind Mestsnres of Keologiesil KITecl lor
Primsii'Y C onstituent Klements of Designated ( rilicnl Ihihitnt
Assessment l.ndpoinl
Moiisuivs of r.cnlniiiciil I-'. ITec Is
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. Aquatic non-vascular plant EC50
b. Terrestrial Plants (qualitative data)
c. Terrestrial Plants (qualitative data)
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.9
a. Aquatic non-vascular plant EC50
b. Terrestrial Plants (qualitative data)
c. Terrestrial Plants (qualitative data)
Alteration of other chemical characteristics necessary
for normal growth and viability of CRLFs and their
food source.
a. Brown Trout LC50
b. Fathead minnow chronic NOAEC
c. Water flea acute EC50
d. Water flea chronic NOAEC
e. Non-vascular plant (freshwater algae) acute EC50
Reduction and/or modification of aquatic-based food
sources for pre-metamorphs (e.g., algae)
a. Aquatic non-vascular plant EC50
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. Terrestrial Plants (qualitative data)
b. Terrestrial Plants (qualitative data)
c. Honey bee oral LD50
d. Rat acute LD50
e. Rat chronic NOAEC
f. Mallard duck acute LD50
g. Mallard duck/ Bobwhite quail chronic NOAEC
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
Reduction and/or modification of food sources for
terrestrial phase juveniles and adults
Alteration of chemical characteristics necessary for
normal growth and viability of juvenile and adult
CRLFs and their food source.
8 All toxicity data reviewed for this assessment are included in Appendix A.
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.
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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 captan to the environment. The
following risk hypotheses are presumed for this endangered species assessment:
• Labeled uses of captan within the action area may directly affect the CRLF by
causing mortality or by adversely affecting growth or fecundity;
• Labeled uses of captan within the action area may indirectly affect the CRLF by
reducing or changing the composition of food supply;
• Labeled uses of captan 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 and/or cover;
• Labeled uses of captan 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 captan 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, and/or
sedimentation);
• Labeled uses of captan 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 captan 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 captan 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 captan within the action area may modify the designated critical
habitat of the CRLF by altering chemical characteristics necessary for normal growth and
viability of juvenile and adult CRLFs.
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2.9.2 Diagram
The conceptual model is a graphic representation of the structure of the risk assessment.
It specifies the stressor (captan), 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 Figures 10 and 11, and the conceptual models for the
aquatic and terrestrial PCE components of critical habitat are shown in Figures 12 and
13. Exposure routes shown in dashed lines are not quantitatively considered because the
resulting exposures are expected to be so low as not to cause adverse effects to the CRLF
and modification to designated critical habitat is expected to be negligible.
Stressor
Long range
atmospheric
transport
Groundwater
Source
Runoff
Exposure
Media
Wet/dry deposition •*'
Uptake/gills
or integument
Uptake/cell,
roots, leaves
Uptake/gills
or integument
Ingestion
Ingestion
Receptors
Attribute
Change
Aquatic Animals
Invertebrates
Vertebrates
Aquatic Plants
Non-vascular
Vascular
Red-legged Frog
Eggs Juveniles
Larvae Adult
Tadpoles
Food chain
Reduction in algae
Reduction in prey
Riparian plant
terrestrial
exposure
pathways see
Figure 2.7
Surface water/
Sediment
Individual
organisms
Reduced survival
Reduced growth
Habitat integrity
Reduction in primary
productivity
Reduced cover
Captan applied to agricultural and non-agricultural use sites in California
Figure 10. Conceptual Model for Pesticide Effects on Aquatic Phase of the Red-
Legged Frog
52
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Captan applied to agricultural and non-agricultural use sites in California
Stressor 1
Long range
atmospheric
transport
\ Spray drift [
| Runoff 1
Source
Dermal
Exposure
Media
Root
Terrestrial
insects
Wet/dry deposition"*"
^¦Ingestion
Ingestion
Ingestion ^
Ingestion
Receptors
Attribute
Change
Figure 11. Conceptual Model for Pesticide Effects on Terrestrial Phase of Red-
Soil
Direct
application
Red-legged Frog
Juvenile
Adult
Individual
organisms
Reduced survival
Reduced growth
Food chain
Reduction in prey
Terrestrial/riparian plants
grasses/forbs, fruit, seeds
(trees, shrubs)
Habitat integrity
Reduction in primary productivity
Reduced cover
Community change
Legged Frog
53
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Stressor
Long range
atmospheric
transport
>¦ Groundwater
Source
Exposure
Media
Wet/dry deposition-*1
Uptake/gills
or integument
Uptake/cell,
roots, leaves
Uptake/gills
or integument
Receptor
Ingestion
* Ingestion
s i
Community
Reduced seedling
emergence or
vegetative vigor
Population
Yield
Reduced
Attribute
Change
Habitat
PCEs
Aquatic Animals
Invertebrates
Vertebrates
Aquatic Plants
Non-vascular
Vascular
Surface water/
Sediment
Food sources
Reduction in algae
Reduction in prey
Red-legged
Frog
Eggs
Juveniles
Individual
organisms
Reduced survival
Reduced growth
Individual
organisms
Reduced survival
Reduced growth
Other chemical
characteristics
Adversely modified
chemical characteristics
Riparian and Upland
plants terrestrial
exposure pathways
and PCEs see Figure
2.9
Captan applied to agricultural and non-agricultural use sites in California
Habitat quality and channel/pond
morphology or geometry
Adverse water quality changes
Increased sedimentation
Reduced shelter
Figure 12. Conceptual Model for Pesticide Effects on Aquatic Components of Red-
Legged Frog Critical Habitat
54
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Captan applied to agricultural and non-agricultural use sites in California
Stressor 1
\ Spray drift [
| Runoff 1
Long range
atmospheric
transport
Source
Dermal
Exposure
Media and
Receptors
Root uptake
Terrestrial
insects
Wet/dry deposition*"
¦~Ingestion
~ Ingestion
Ingestion
Attribute
Change
Habitat
PCEs
Soil
Direct
application
Red-legged
Frog
Juvenile
Food resources
Reduction in food
sources
Population
Reduced survival
Reduced growth
Reduced
Individual
organisms
Reduced survival
Reduced growth
Other chemical
characteristics
Adversely modified
chemical characteristics
Terrestrial plants
grasses/forbs, fruit,
seeds (trees, shrubs)
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
Figure 13. Conceptual Model for Pesticide Effects on Terrestrial Components of
Red-Legged Frog Critical Habitat
2.10 Analysis Plan
In order to address the risk hypothesis, 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 captan 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 captan 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 Hypothesis and Conceptual Model
2.10.1.1 Measures of Exposure
The environmental fate properties of captan indicate that runoff and spray drift are the
principle potential transport mechanisms of captan to the aquatic and terrestrial habitats
55
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of the CRLF. In this assessment, transport of captan through runoff and spray drift is
considered in deriving quantitative estimates of captan exposure to CRLF, its prey and its
habitats. Captan has low potential for volatility and measured concentrations were below
the level of detection in air monitoring samples, therefore long range transport is
unlikely. Deposition of captan was estimated from local spray drift on terrestrial habitats
that neighbor application sites.
Measures of exposure are based on aquatic and terrestrial models that predict estimated
environmental concentrations (EECs) of captan using maximum labeled application rates
and methods. 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. The THERPS model was used
to refine terrestrial dose-based EECs by including amphibian/reptile specific allometric
equations. The model used to derive EECs relevant to terrestrial and wetland plants is
TerrPlant. These models are parameterized using relevant reviewed registrant-submitted
environmental fate data.
PRZM (v3.12beta, May 24, 2001) and EXAMS (v2.98.04, Aug. 18, 2002) are screening
simulation models coupled with the input shell pe4v01.pl (Aug.8, 2003) to generate daily
exposures and l-in-10 year EECs of captan that may occur in surface water bodies
adjacent to application sites receiving captan 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 water
body that is 2 meters deep (20,000 m3 volume) with no outlet. PRZM/EXAMS is used to
estimate screening-level exposure of aquatic organisms to captan. 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 l-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 aquatic invertebrate chronic
exposure, which are also potential prey items.
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 represented the 95th percentile of residue values from actual field
measurements (Hoerger and Kenega, 1972). The Fletcher et al. (1994) modifications to
the Kenega nomograph are based on measured field residues from 249 published research
papers, including information on 118 species of plants, 121 pesticides, and 17 chemical
classes. These modifications represent the 95th percentile of the expanded data set. For
56
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modeling purposes, direct exposures of the CRLF to captan through contaminated food
are estimated using the EECs for the small bird (20 g) which consumes small insects.
Dietary-based and dose-based exposures of potential prey (small mammals) are assessed
using the small mammal (15 g) which consumes short grass. 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. Estimated
exposures of terrestrial insects to captan are bound by using the dietary based EECs for
small insects and large insects.
Spray drift models, AGDISP is used to assess exposures of terrestrial phase CRLF and its
prey to captan deposited on terrestrial habitats by spray drift. AGDISP (version 8.13;
dated 12/14/2004) (Teske and Curbishley, 2003) is used to simulate aerial and ground
applications using the Gaussian farfield extension.
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 captan to birds is similar 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
57
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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
Risk characterization is the integration of exposure and ecological effects characterization
to determine the potential ecological risk from agricultural and non-agricultural uses of
captan, 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 captan
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
D).
For this endangered species assessment, listed species LOCs are used for comparing RQ
values for acute and chronic exposures of captan directly to the CRLF. If estimated
exposures directly to the CRLF of captan 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 captan 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 LOC, then the
effects determination is a LAA. If the RQ is between the listed species LOC and the non-
listed 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."
3. Exposure Assessment
3.1 Label Application Rates and Intervals
Captan is used as both a foliar treatment and a seed treatment for food and non-food uses.
The pesticide has several formulations and is applied by various methods, including
aerial, airblast, dust and groundboom. It used as a foliar spray on almond, strawberry,
ginseng, and several orchard and vineyard crops. The EECs based on the foliar spray
food uses and seed treatment uses were modeled using the appropriate PRZM-EXAMS
scenarios (Table 3.01). Seed treatment application rates are found in Table 2.06.
Captan use on berries (blueberries, caneberries, raspberries, blackberry, dewberry, and
loganberry) was modeled using the CA wine grape scenario. According to NASS,
58
-------
blueberries are grown in the coastal valley. The CA wine grape scenario represents a field
in Northern coastal CA (Sonoma, Napa, Lake, and Mendocino Counties). The
meteorological station for this scenario is located in San Francisco. The meteorological
station and the soil for the CA wine grape scenario overlap in range with the region of
blueberry cultivation. The range of the other berries in California is similar to blueberries.
However, captan use on grapes was modeled using the CA standard grape scenario which
represents a wide range of area and represents all grape-growing areas in California.
Captan is used on golf course turf, turf sod farms, and dichondra grasses as a foliar
application. The maximum application rate for turf is 4.3 lb a.i./A with 2 applications at a
7-day interval. Ornamental grasses in non-pasture areas are also treated for several
diseases and can be sprayed beginning at spring and applied throughout the season. The
maximum single application rate for ornamental grasses is also 4.3 lb a.i./A. The
maximum annual application rate and number of applications were not specified on the
Drexel Chemical Company labels, therefore it was estimated for this assessment that the
season would last approximately seven months and result in a maximum of 26
applications with 7-day intervals. These Drexel Chemical Company labels include EPA
Reg. 019713-00156, 019713-00235, 019713-00362, 019713-00385, and 019713-00405.
These uses were modeled using the California turf PRZM EXAMS scenario (Table
3.02).
Captan can be used to treat lawn seedbeds and preplant seedlings or transplants of roses
or other shrubs, trees, and flowers at 6.53 lb a.i./A with incorporation in the top 3-4
inches of soil before planting. Captan is also used as a preplant dip for flowers (azaleas,
begonias, carnations, chrysanthemum, and gladiolus). Captan can be used to treat
damping-off and corm rot for azaleas, begonias, chrysanthemum, and gladiolus by
dipping the cuttings, tubers, or corms before bedding or planting at rates of 2 lb a.i./ 100
gallon to 0.75 lb a.i./10 gallons. The uses were not modeled in this assessment because
exposure is expected to be negligible from dip and preplant treatment as compared to the
other modeled ornamentals uses applied by aerial and ground application.
Azaleas and camellias can also be treated with captan for petal blight by spraying the
flowers and/ or the soil through bloom at rates of 0.5 to 1.0 lb a.i./A. Bloom can be up to
5 weeks for azaleas and 3 months for camellias according to Cheryl Wilen at University
of California at Davis (personal communication). Carnations, chrysanthemum and roses
are treated for several diseases and the flowers can be sprayed at the first sign of disease
and applied as needed. A crop cycle for chrysanthemum is 7-10 weeks before blooming.
So if they have leaf diseases, they would need to apply during that period. Application to
roses is to occur at first sign of disease at a rate of 1 lb a.i./A and could occur year-round
in California. Foliar application to these flowers was not assessed because environmental
exposure is expected to be lower than the ornamental grass and turf uses. In addition,
many of these flowers are treated in greenhouses or shade houses which results in
minimal environmental exposure (Wilen et al, 2002).
59
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Table 3.01. (apian l-'olia
* Application Kales lor l-'ood I ses and modeled
PKZM/IAAMS Scenarios
S< I N AUK)
CROP
M;i\.
M;i\. # of
Min.
M;i\.
Application
Applications
Inlcr\;il
An miiil
RiltC (ll)N
licl \\ con
I NO RiltC
iii/A)
Apps.
(d;i\s)
(lbs :ii)
CA almond S ID
ALMOND
4.5
4
-
"Ml DO
CA potato
Ginseng
2.0
8
7
16.00
CA strawberry (non plastic)
STRAWBERRY
3.0
8
7
24.00
RLF
CA fruit STD
APPLE
4.0
8
5
32.00
APRICOT
2.5
5
5
12.50
CHERRY
2.0
7
7
14.00
NECTARINE
4.0
6
3
24.00
PEACH
4.0
8
3
32.00
PLUM/ PRUNE
3.0
9
7
27.00
CA wine grapes RLF *
BLACKBERRY
2.0
5
10
10.00
BLUEBERRY/
2.5
14
7
35.00
CANEBERRY/
RASPBERRY
DEWBERRY
3.13
3
10
9.39
LOGANBERRY
1.956
5
3
9.78
CA grapes STD **
GRAPES
2.0
6
10
12.00
* The meteorological station and soil types for the CA wine grape scenario are representative of berry
growing areas in Northern California
** The CA grapes standard scenario represents all grape growing areas in California
Table 3.02. ('apian l-'oliar Application Kales lor TinT/ Ornamentals and
PKZM/IAAMS Scenarios
S( T.NAKIO
CROP
M;i\.
Application
Killo (lbs iii/A)
m«i\. # or
Applications
Mill. Inlcr\;il
Between Apps.
t(lil\S)
CA turf RLF
Golf Course Turf, Sod Farm
Turf, Dichondra grasses
4.3
2
7
Ornamental Grasses (non-
pasture areas)1
4.3
26
7
Label (Drexel Chemical Company) does not indicate a maximum number of applications or annual rate
for ornamental grasses in non-pasture areas (EPA Reg. 019713-00156, 019713-00235, 019713-00362,
019713-00385, 019713-00405).
3.2 Aquatic Exposure Assessment
For tier 2 surface-water assessments, two models are used in tandem. PRZM simulates
fate and transport on the agricultural field. The version of PRZM (Carsel et al., 1998)
used was PRZM 3.12 beta, dated May 24, 2001. The water body is simulated with
EXAMS version 2.98, dated July 18, 2002 (Burns, 1997). Tier 2 simulations are run for
multiple (usually 30) years and the reported EECs are the concentrations that are
expected once every ten years based on the thirty years of daily values generated by the
simulation. PRZM and EXAMS were run using the PE4 shell, dated May 14, 2003,
which also summarizes the output. Input parameters are given in Table 3.03.
60
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Aquatic exposures are quantitatively estimated for all of assessed uses using scenarios
that represent high exposure sites for captan 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 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.
Crop-specific management practices for all of the assessed uses of captan 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.
Tsihk'3.03. PUZM/KYVM Input P;ii;i meters lor (
Piii'ii meter
Value iiiul I nil
Sources
Molecular Weight
310.00 gram/mol
Product Chemistry
Henry's Law Constant
9.6E-9 Atm.M3 Mol"1
Estimated
Vapor pressure
8 x 10"8 mm Hg @ 25°C
Product Chemistry
Water Solubility (pH 7, 25°C)
3.3 mg/L
Product Chemistry
Soil Koc
200 mg/L
D318452-IR-4- Ginseng1
Aqueous Photolysis half-life (pH 7)
0.42 days
D318452-IR-4- Ginseng1
Aerobic Aquatic Metabolism
3.75 days
D318452-IR-4- Ginseng1
Anaerobic Aquatic Metabolism
1.85 days
D318452-IR-4- Ginseng1
Aerobic soil half-life
1.25 days
D318452-IR-4- Ginseng1
Anaerobic soil half-life
1.85 days
D318452-IR-4- Ginseng1
Hydrolysis
0.25 days
D318452-IR-4- Ginseng1
Pesticide is wetted-in
No
Product label
Chemical Application method (CAM)
2 for foliar spray
4 for seed treatment
EFED Guidance2
Application Efficiency
0.95 for foliar spray
0.99 for ground appl.
EFED Guidance2
1IR-4- Local Registration for Captan Use on Ginseng, 2006 (D318448, D318449, D318450, D318451, and D318452)
2 Guidance for selecting input parameters in modeling for environmental fate and transport of pesticides. Version II.
February 27,2002.
61
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3.2.1 Aquatic Modeling Results
Using the various PRZM EXAMS scenarios and the application practices for captan the
aquatic EECs were estimated. For foliar application to the food uses, the estimated
aquatic exposures are highest for captan use on almonds at four applications with a peak
EEC of 21.6 |ig/L for aerial application (Table 3.04). The peak estimated aquatic
exposure for captan use on golf courses, sod farms and dichondra grasses with a
maximum of 2 applications is 12.2 |ig/L for aerial application (Table 3.05). The peak
estimated aquatic exposure for captan use on ornamental grasses with a maximum of 26
applications is 28.6 |ig/L for ground application. For seed treatment for the food uses,
the estimated aquatic exposure is highest for wheat with a peak EEC of 0.51 |ig/L using
the conservative assumption of no ground incorporation (Table 3.06). For
grass/forage/fodder/ hays grown for seed using the California turf scenario and assuming
a two inch incorporation depth, the estimated aquatic exposure is 4.05 |ig/L. For
application of captan as a lawn seedbed treatment with 3 inch incorporation, the peak
estimated aquatic exposure is 15.64 |ig/L.
The food use which resulted in the highest EECs was captan use on almonds. The
maximum application rate is 4.5 lb a.i./A with 4 applications per year. Almond was also
modeled at one application per year to estimate a lower bound of exposure. At one
application, the peak EEC is 13.85 |ig/L for aerial application as compared to the peak
EEC of 21.6 |ig/L for four applications (Table 3.04).
62
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Table 3.04. Aquatic KIX s (iig/l.) lor (apian l-'oliar Applic:i(ion lo (lie lootl I scs in
CaliCoi'iiia
CROP
Peak EEC
21 dav EEC
60 (lav EEC
ALMOND (4 applications)
Aerial Application
21.567
1.3467
0.5911
Ground Application
11.995
0.5541
0.2190
ALMOND (1 application)
Aerial Application
13.853
0.414
0.145
APPLE
Aerial Application
11.19
1.465
0.8281
Ground Application
2.239
0.293
0.1656
APRICOT
Aerial Application
6.998
0.9303
0.3256
Ground Application
1.4
0.1861
0.0651
CANEBERRY (BLACKBERRY/ RASPBERRY)
Aerial Application
5.597
0.444
0.2690
Ground Application
1.1271
0.0986
0.0604
BLUEBERRY
Aerial Application
10.1663
0.6886
0.6336
Ground Application
5.3309
0.2458
0.1653
CHERRY
Aerial Application
5.597
0.5183
0.3893
Ground Application
2.6275
0.1624
0.0984
DEWBERRY
Aerial Application
8.771
0.6956
0.2542
Ground Application
1.754
0.1448
0.0580
GINSENG
Aerial Application
5.597
0.4460
0.4153
Ground Application
1.119
0.0892
0.0831
GRAPES
Aerial Application
5.5979
0.4637
0.3227
Ground Application
1.12
0.1173
0.0728
LOGANBERRY
Aerial Application
5.4818
0.7422
0.2640
Ground Application
1.4729
0.1584
0.0599
NECTARINE
Aerial Application
11.2
1.786
0.62520
Ground Application
2.239
0.3572
0.125
PEACH
Aerial Application
11.2
2.081
0.8318
Ground Application
2.239
0.4162
0.1664
PLUM/ PRUNE
Aerial Application
8.396
0.6698
0.6998
Ground Application
1.679
0.134
0.1400
STRAWBERRY
Aerial Application
8.396
0.7425
0.6517
Ground Application
2.7934
0.208
0.1512
63
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Tsihlc 3.05. Aqusilic KIX s (iig/l.) lor Csiplsin l-'olisir Application lo TiiiTiiml
Ornsimcnlsil I sos in ( ;ilir»rni;i
Crop
Peak EEC
21 (lav EEC
60 (lav EEC
Golf course turf/ Sod Farms (2 applications)
Aerial Application
12.215
0.732
0.256
Ground Application
3.605
0.220
0.077
Ornamental Grasses (26 applications)
Aerial Application
27.474
1.194
1.093
Ground Application
28.571
0.761
0.298
Tsihlc 3.06. Aqusilic
KKCs (u«/l.) lor ("sipi
sin Seed Tresilmenl in ('iililornisi
Crop
Peak I'.r.C
21 &.i\ r.r.c
6o da\ r.r.c
Alfalfa/ CA alfalfa
0.028
0.00076
0.00027
Clover/ CA alfalfa
0.024
0.00065
0.00023
Flax/ CA alfalfa
0.019
0.00052
0.00018
Barley/ CA wheat
0.17
0.0046
0.0016
Wheat (1.5"
incorporation)/ CA
wheat
0.30
0.0082
0.0029
Wheat (no
incorporation)/ CA
wheat
0.51
0.014
0.0049
Sorghum/ CA wheat
0.027
0.0007
0.00026
Oats/ CA wheat
0.21
0.0058
0.0020
Rye/ CA wheat
0.25
0.0068
0.0024
Beets/ CA row crop
0.0066
0.00018
6.28E-05
Pepper/ CA row crop
0.0011
2.99E-05
1.05E-05
Tomato/ CA tomato
0.00012
4.69E-06
1.64E-06
Broccoli/ Cabbage/
Cauliflower /CA cole
crop
0.0013
3.49E-05
1.22E-05
Collards/CA cole crop
0.0015
4.13E-05
1.45E-05
Kale/CA cole crop
0.0019
5.08E-05
1.78E-05
Mustard greens/CA cole
crop
0.016
0.00045
0.00016
Brussels sprouts/ CA
lettuce
0.00072
2.17E-05
7.59E-06
Spinach/ CA lettuce
0.059
0.0018
0.00062
Melons-water/ CA
melons
0.059
0.0018
0.00062
Melons-musk/ CA
melons
1.47E-06
3.89E-08
1.36E-08
Melons-cantaloupe/ CA
melons
2.26E-06
5.98E-08
2.09E-08
Squash/ CA melons
1.47E-06
3.89E-08
1.36E-08
Cucumber/ CA melons
1.73E-06
4.59E-08
1.61E-08
Onion/ CA onion
0.0038
0.00010
3.59E-05
Radish/ CA onion
0.0020
5.34E-05
1.87E-05
Potato/ CA potato
0.094
0.0027
0.00095
Turnip/ CA potato
0.094
0.0027
0.00095
Grass/Forage/Fodder/
Hayes grown for seed 2"
4.049
0.113
0.040
incorporation/ CA turf
64
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Grass seed Bed
Treatment 3"
15.64
0.438
0.153
incorporation/ CA turf1
1 This use is not a seed treatment use but it was modeled similar to seed treatment in PRZM/EXAMS to
account for the 3" incorporation depth.
3.2.2 Existing Monitoring Data
A critical step in the process of characterizing EECs is comparing the modeled estimates
with available surface water monitoring data. Captan has a limited set of surface water
monitoring data relevant to the CRLF assessment. Most of this data is non-targeted (i.e.,
study was not specifically designed to capture captan concentrations in high use areas).
Data from the USGS NAWQA program (http://water.usgs.gov.nawqa) and California
Department of Pesticide Regulation (CDPR) was searched for captan data. In addition,
air monitoring data for captan are summarized.
3.2.2.1 Surface Water Monitoring Data
The California Department of Pesticide Regulation (CDPR) monitoring program data
were accessed and reviewed. Sampling for captan only occurred on one day, December
13, 1994; therefore, this data was deemed insufficient for analysis. The sampling that
occurred found no detectable levels of captan at 4 sites in Santa Cruz County and 3 sites
neighboring Monterey County. The surveyed sites included a slough, a lagoon, a river,
and drainage ditches. The CDPR data contained no information regarding captan
degradates. At present time, neither captan nor its degradates are included in the USGS-
NAWQA.
3.2.2.2 Atmospheric Monitoring Data
Ambient air monitoring for captan and THPI was conducted four days a week from May
11 through June 4, 1993, at three sites in Kern County. The background site was located
at the California Air Resources Board air monitoring station in Bakersfield. Monitoring
coincided with expected applications to grape vineyards. All samples analyzed were
below the minimum detection level (MDL). The captan MDL is 0.013 |ig/m3 (1.1 ppt)
and THPI MDL is 0.026 |ig/m3 (4.3 ppt) for 24 hour samples.
Application site monitoring for captan and THPI was conducted in May 1993 before,
during, and for 72 hours after an application to a grape vineyard. In Tulare County captan
was applied by ground equipment at the rate of 3.9 pounds of active ingredient per acre.
Thirty-six of 40 samples analyzed for captan were below the MDL. All samples for THPI
were below the MDL.10
3.2.3 Spray Drift Buffer Analysis
10 From California Air Resources Board (2002). Pesticide Air Monitoring Results. California Department
of Pesticide Programs/EH- 02-01.
65
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When considering the terrestrial habitats of the CRLF, spray drift from use sites onto
non-target areas could potentially result in exposures of the CRLF, its prey and its habitat
to captan. Therefore, it is necessary to estimate the distance from the application site
where spray drift exposures do not result in LOC exceedances for organisms within the
terrestrial habitat.
Since spray drift is the most likely means through which non-target terrestrial organisms
will be potentially exposed to captan, the AGDISP model (version 8.13) is used to
estimate the terrestrial distance from the site of application to where RQs are predicted to
fall below the endangered species LOC. The highest single maximum application rate
allowed on the label for captan uses were modeled to determine the maximum potential
off-site estimated environmental concentrations (EECs) for a single application based on
upper bound Kenaga values. The highest single maximum application rate was
determined for each land use type including agriculture (includes ornamentals) and
orchard/ vineyard. Almond is the orchard/vineyard crop with the highest application rate
with a single application of 4.5 lb a.i./acre. Ornamental grasses is the agriculture crop
with the highest application rate with a single application of 4.3 lb a.i./acre.
Aerial application is modeled since spray drift is expected to travel further with aerial
applications than with ground applications because of the higher release heights. Table
3.07 has selected input parameters used in AGDISP modeling.
Table 3.07. AGDISP Input parameters lor almond and eaplan Corninhition
Application. Method
Aerial
(Air Tmctor AT 401)
Almond canopy Height
30 ft
Release height
40ft
Swath Displacement
Vi swath
Spray Volume
10 gal-acre"1
Non-volatile fraction
0.1
Active Fraction
0.0374
Specific Gravity (carrier)
1.0
Specific Gravity (captan)
1.27
Fraction of applied1
0.0267
Initial average deposition2
0.120
1 = LOC/RQ
2= (Fraction of applied) x (Application rate for almond in lbs a.i/acre)
A single application was modeled versus multiple applications because it is unlikely that
the same terrestrial invertebrate would be exposed to the maximum amount of spray drift
from multiple applications. For a terrestrial organism to receive the maximum
concentration of captan from multiple applications, it would require that each application
is made under identical atmospheric conditions (e.g., same wind speed and same wind
direction) and the terrestrial organism being exposed is located in the same location
(which receives the maximum amount of spray drift) after each application.
66
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Additionally, certain factors, including variations in topography, cover, and
meteorological conditions over the transport distance are not accounted for by the
AGDISP 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 AGDISP will 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.). For this
assessment, a single application was assessed.
Furthermore, conservative assumptions are made regarding the droplet size distributions
being modeled ('ASAE Very Fine to Fine' for almond uses and the application method
(aerial), release heights and wind speeds. Alterations in any of these inputs would
decrease the area of potential effect. As noted in Section 3.2.4.2, no captan was detected
in the air monitoring studies conducted in CA during the months of captan application.
Therefore, it is unlikely that any terrestrial invertebrate outside the buffer from the site of
captan application would actually receive a level of exposure high enough to cause an
adverse effect.
3.2.4 Downstream Dilution Analysis
In order to determine the extent of the action area in aquatic habitats, the agricultural and
orchard uses resulting in the greatest ratios of the RQ to the LOC for any endpoint for
aquatic organisms is used to determine the distance downstream for concentrations to be
diluted below levels that would be of concern {i.e. result in RQs above the LOC). To
complete this assessment, the greatest ratio of aquatic RQ to LOC was estimated. This
ratio is used to identify all stream reaches downstream from the initial area of concern
where the percent cropped area (PCA) for the land uses identified for captan are greater
than 1/20 or 5%. All streams identified as draining upstream catchments greater than 5%
of the land class of concern, would be considered part of the action area. Results are
shown is Section 5.1.4.
3.2 Terrestrial Animal Exposure Assessment
T-REX (Version 1.3.1) is used to calculate dietary and dose-based EECs of captan 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 serving as potential prey of CRLF adults. T-REX simulates a 1-year time
period. For this assessment, spray applications and seed treatment of captan are
considered.
Maximum exposure levels were calculated for spray applications of captan using the
maximum use rate for the food uses (peach) of 4 lbs ai/A of 8 applications at a 3-day
application interval. In addition, minimum exposure levels were calculated for spray
applications of captan using the minimum use rate for the food uses (caneberries) of 2 lb
ai/A of 5 applications at a 10-day application interval. This range of exposure estimates
the bounds for all of the food uses. Maximum exposure levels were also calculated for
67
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application of captan to turf and ornamental grasses. Use specific input values, including
number of applications, application rate and application interval are provided in Table
3.08.
Foliar dissipation half-lives are incorporated into the TREX model. The default foliar
dissipation half-life of 35 days was used to provide an upper bound captan residue
concentration on foliage (Willis and McDowell, 1987). Additionally, a foliar residue
wash-off half-life of 10 days was used to estimate captan concentrations on foliage (U.S
EPA, 1999). Results are presented using both the 10-day (lower bound) and 35-day
(upper bound) half lives. It should also be noted that any captan that reaches the soil
surface after application would be subject to an aerobic soil metabolism half-life of less
than a day.
Table 3.08. Input Parameters lor Koliar Applications I sell to Derive Terrestrial
KKCs lor Captan with T-UK\
I so (Application method)
Application r;i(o
(Ibs ;ii/.\)
Number of Applications
;iii(l lnler\;il
Caneberry / Raspberry/Blackberry
2
5, 10-day
Peach
4
8, 3-day
Golf course turf/ sod farm (turf)/ dichondra grasses
4.3
2, 7-day
Ornamental grasses
6.39
26, 7-day
For modeling purposes, exposures of the terrestrial phase of the CRLF to captan through
contaminated food are estimated using the EECs for the small bird (20 g) which
consumes small insects. Dietary-based and dose-based exposures of potential
mammalian prey are assessed using the small mammal (15 g) which consumes short
grass. 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 prey
(Table 3.09)
Table 3.09. 1 pper-boiind
Kxposnres of the Terrest
between foliar dissipatioi
I SO
kenega Nomogram KIX's for Dietary- and Dose-based
'ial-phase ( KI.I- and its Prey to Captan (KIX s bracketed
half lives of 10 and 35 davs).
r.r.Cs for Torres!ri;il-phiise
( KIT (suiiill birds consuming
sm;iII insects)
r.r.Cs lor Miiiiiniiiliiin Pro
(suiiill niiiinniiils consuming short
iil'ilSS)
l)ie(;ir\-
hiiscd IT.(
(ppni)
l)osc-l);iscd t'.t'.C
(ni;i/k;i-l)\\)
l)ict;ir\-bused
I I.( (ppni)
Dose-biised I I.(
(niii/kii-lm)
Caneberry/
Raspberry/Blackberry
523 - 945
596 - 1076
930 - 1679
887 - 1601
Peach
2331 - 3542
2655 - 4033
4144-6296
3951 -6003
Golf course turf/ sod farm
(turf)/ dichondra grasses
938 - 1086
1068 - 1237
1667 - 1930
1590 - 1841
Ornamental grasses (26 appl)
1510 -4362
1720 - 4968
2685 - 7755
2559 -7394
T-REX is also used to calculate EECs for terrestrial insects exposed to captan. Available
acute contact toxicity data for bees exposed to captan (in units of |ig a.i./bee), are
68
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converted to |ig a.i./g (of bee) by multiplying by 1 bee/0.128 g. Dietary-based EECs
calculated by T-REX for captan residues on small and large insects (units of a.i./g) are
used to bound an estimate of exposure to bees. The EECs are later compared to the
adjusted acute contact toxicity data for bees in order to derive RQs (Table 3.10).
1 able 3.10. KKC's (ppm) lor Indirect K fleets lo the Terrestrial-Phase ( UI.I- via
K fleets lo Terrestrial Invertebrate Prev Items (KIX s bracketed between foliar
dissipation hall'lives ol' 10 and 35 davs).
1 se
Sniiill Insect
l.iirge Insect
Caneberry / Raspberry/Blackberry
523 - 945
58 - 120
Peach
2331 - 3542
259 -394
Golf course turf/ sod farm (turf)/ dichondra grasses
938 - 1086
104-121
Ornamental grasses
1510 -4362
168-485
The T-HERPS model was used to refine dose-based risk estimations. T-HERPS is a
modification of T-REX which includes amphibian/reptile specific allometric equations,
weight classes appropriate for the CLRF, and prey items specific to the CLRF. It is
important to note that while the allometric equations and prey items are more specific to
the frog, the toxicity data used in this assessment are that for a surrogate species
(bobwhite quail and mallard duck). It is unknown what direction use of the surrogate
toxicity data might bias the estimate. T-HERP groups the frogs into three classes: small
(1.4g), medium (37g), and large (238g). The two smaller weight classes most closely
approximate the 20g juvenile that exceeded LOCs using the T-REX model. EEC are
provided in Table 3.11.
'Cable 3.11. KIX s lor Direct K
exposures resulting from appl
with 10-dav foliar dissipation
Teds lo the terrestrial-phase (KIT". based on captan
cations to peaches (highest foliar application rale)
tall-life.
l-'oori
D(isc-I);iscd Acute I'.IX
1.4 "CUM-
Doso-hiisod
I'.IX
j-7»c ui.r
Dosc-hiisi'ri
i:i.(
23S » CKI.I-"
Small Insects
91
89
58
Large Insects
10
10
6
Small Herbivore mammals
NA
NA
402
Small Insectivore mammals
NA
NA
25
Small Terrestrial-phase Amphibians
NA
NA
2
NA: Not Applicable (size class of frog too small to consume mammals and amphibians)
69
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TerrPlant (Version 1.1.2) is used to calculate EECs for non-target plant species inhabiting
dry and semi-aquatic areas. EECs were estimated based on the use with the highest
single application rate, almond at 4.5 lb a.i./A for aerial application. A runoff value of
0.01 is utilized based on captan's solubility, which is classified by TerrPlant as <10
mg/L. Drift is assumed to be 5% for aerial application. Soil incorporation is assumed to
be 1 for aerial applications. EECs relevant to terrestrial plants consider pesticide
concentrations in drift and in runoff. EECs for spray drift alone, total for dry areas, total
for semi-aquatic areas are 0.23, 0.27, and 0.68 lbs ai/acre. An example output from
TerrPlant v. 1.2.2 is available in Appendix K.
4. Effects Assessment
This assessment evaluates the potential for captan to directly or indirectly affect the
CRLF or modify its designated critical habitat. As previously discussed in Section 2.7,
assessment endpoints for the CRLF include direct toxic effects on the survival,
reproduction, and growth of CRLF, as well as indirect effects, such as reduction of the
prey base and/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. Acute (short-term) and chronic
(long-term) toxicity information is characterized based on registrant-submitted studies
and a comprehensive review of the open literature on captan.
As described in the Agency's Overview Document (U.S. EPA, 2004), the most sensitive
endpoint for each taxon is used for risk estimation. For this assessment, evaluated taxa
include aquatic-phase amphibians, freshwater fish, freshwater invertebrates, aquatic
plants, birds (surrogate for terrestrial-phase amphibians), mammals, terrestrial
invertebrates, and terrestrial plants.
Toxicity endpoints are established based on 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). 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
70
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(5) there is an explicit duration of exposure.
Data that pass the ECOTOX screen are 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 that are more conservative than
the registrant-submitted data are considered. The degree to which open literature data are
quantitatively or qualitatively characterized is dependent on whether the information is
relevant to the assessment endpoints {i.e., maintenance of CRLF survival, reproduction,
and growth) identified in Section 2.8. For example, endpoints such as behavior
modifications are likely to be qualitatively evaluated, unless quantitative relationships
between modifications and reduction in species survival, reproduction, and/or growth are
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 Appendix G. Rationales for rejection of those studies that did not pass the
ECOTOX screen are included in Appendix G. Rationales for those studies that did pass
the ECOTOX screen but were not included in this endangered species risk assessment
are:
• Endpoint not more sensitive than submitted data
• Efficacy data not useful for assessment
• Exposure route not relevant for the CRLF
• Study was not conducted using captan (error in the ECOTOX screen)
• Exposure levels could not be converted to units useful for risk assessment (e.g.,
could not convert to lbs ai/acre for terrestrial plants or to |ig ai/individual for
bees)
In addition to registrant-submitted and open literature toxicity information, other sources
of information, including use of the acute probit dose response relationship to establish
the probability of an individual effect and reviews of the Ecological Incident Information
System (EIIS), are utilized to further refine the characterization of potential ecological
effects associated with exposure to captan. A summary of the available aquatic and
terrestrial ecotoxicity information, use of the probit dose response relationship, and the
incident information for captan are provided in Sections 4.1 through 4.4, respectively.
The captan degradates, THPI and THPAm, are less toxic than the parent compound for
aquatic receptors. As shown in Table 4.01, comparison of available toxicity information
indicates lesser aquatic toxicity than the parent for freshwater fish, invertebrates, and
aquatic plants. Toxicity data for terrestrial species are not available for the degradates.
Because the degradates are several orders of magnitude less toxic than the parent, the
degradates were not assessed for effects to the CRLF.
71
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Table 4.01. Comparison of Aquatic Acute Toxicity Values for Captan and
dcsrdd 120,000
>113,000
>180,000
THPAm
> 126,000
No data
No data
4.1 Toxicity of Captan to Aquatic Organisms
Table 4.02 summarizes the most sensitive aquatic toxicity endpoints for the CRLF, 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 for the CRLF is presented below. Additional information
is provided in Appendix A.
Tabic 4.02. Aquatic Toxicity Profile for Captan
I'.ndpoinl
Surmfiale
Species
Toxicity miIiic used in
llic risk assessment
Source
( ilalion
( (MilIllCIIIS
Direct Effects
Acute Toxicity to
Frog
(Aquatic Phase)
Salmo trutta
(Brown trout)
LC50 — 26.2 (ig/L
Very Highly Toxic
Probit slope unavailable,
no partial mortalities
MRID
40098001
Supplemental
Chronic Toxicity to
Frog
(Aquatic Phase)
Pimephales
promotes
(Fathead
minnow)
NOAEC = 16.5 (ig/L
LOAEC = 39.5 ng/L
MRID
00057846
Acceptable
Reductions in adult and
larval survival, growth
and overall larval-
juvenile development,
survival of the juvenile
species, a reduction in
eggs laid, and an
inability for juveniles to
reproduce
Indirect Effects (Prey Reduction))
Acute Toxicity to
Aquatic Invertebrates
Daphnia
magna
(Water flea)
EC50 = 8400 ng/L
Slope= 1.187
Moderately Toxic
MRID
GS0120041
Acceptable
Chronic Toxicity
to Aquatic
Invertebrates
Daphnia
magna
(Water flea)
NOAEC = 560 ng/L
LOAEC = 1000 ng/L
MRID
441488-01
Supplemental
Indirect Effects (Habitat Modification)
Acute Toxicity to
Plants
(non-vascular)
Scenedesmus
subspicatus
(Green Algae)
EC50 = 320 ng/L
MRID
00137688
Supplemental
Acute Toxicity to
Plants (vascular)
Lemna gibba
(Duckweed)
LC50 > 12,700 Hg/L
MRID
44806503
Acceptable
72
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4.1.1 Toxicity to Freshwater Fish and Amphibians
Ecotoxicity data for freshwater fish are generally used as surrogates for aquatic-phase
amphibians when amphibian toxicity data are not available (U.S. EPA, 2004). Some
amphibian data were located in ECOTOX (#90515). Toxicity data for two species, the
African clawed frog {Xenopus laevis,) and the Spanish ribbed newt (Pleurodeles waltl)
indicated that mortality effects for amphibians occur in concentrations similar to lethal
endpoints for fish (Mouchet et al, 2006). Acute toxicity for Xenopus laevis resulted in
LC50 = 119.4 |ig/L for exposure to captan in mineral water and LC50 = 354 |ig/L in
reconstituted water. Acute toxicity for Pleurodeles waltl resulted in LC50 = 311 |ig/L for
exposure to captan in mineral water and LC50 = 500 |ig/L in reconstituted water. Captan
had genotoxic effects, including impacts to DNA structure and cell reproduction, in both
species at concentrations of 62.5 |ig/L (in mineral water) and higher. The results of this
study are based on nominal concentrations because measured concentrations were not
taken. In addition, turbidity was observed in the reconstituted water treatments; therefore,
there are uncertainties associated with the results of this study. Thus EFED used the
toxicity value from the fish data to calculate RQs.
Freshwater fish data were used as a surrogate to estimate direct acute and chronic risks to
the CRLF. Freshwater fish toxicity data were also used to assess potential indirect effects
of captan to the CRLF. Direct effects to freshwater fish resulting from exposure to
captan may indirectly affect the CRLF via reduction in available food. As discussed in
Section 2.5.3, over 50% of the prey mass of the CRLF may consist of vertebrates such as
mice, frogs, and fish (Hayes and Tennant, 1985).
Captan is highly toxic to very highly toxic to freshwater fish (LC50 = 26.2 - 137 |ig/L) on
an acute basis. The brown trout was found to be the most sensitive freshwater fish species
tested (LC50 = 26.2 |ig/L, MRID 40098001). Due to lack of partial mortalities the probit
slope could not be determined for this study.
A freshwater fish early life-stage chronic toxicity study on fathead minnow (Pimephales
promales) was used to evaluate the chronic toxicity of captan. Captan had an NOAEC of
16.5 |_ig/L and an LOAEC of 39.5 |_ig/L (MRID 00057846). Endpoints affected in the
study include adult and larval survival rate, growth and overall larval-juvenile
development, survival of the juvenile species, a reduction in eggs laid, and an inability
for juveniles to reproduce for freshwater fish exposed to captan.
4.1.2 Toxicity to Freshwater Invertebrates
Freshwater aquatic invertebrate toxicity data were used to assess potential indirect effects
of captan to the CRLF. Direct effects to freshwater invertebrates resulting from exposure
to captan may indirectly affect the CRLF via reduction in available food items. As
discussed in Section 2.5.3, the main food source for juvenile aquatic- and terrestrial-
phase CRLFs is thought to be aquatic invertebrates found along the shoreline and on the
water surface, including aquatic sowbugs, larval alderflies and water striders.
73
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Acute freshwater toxicity tests using the Daphnia magna indicate captan is moderately
toxic (LC50 = 8400 |_ig/L; MRID GS0120041). A freshwater early-life-stage cycle test
using the Daphnia magna exposed to captan was submitted (MRID 441488-01). Captan is
categorized as a reproductive inhibitor in freshwater invertebrates due to parental and
juvenile reductions in growth, survival, length as well as decreased number of juveniles.
The NOAEC and LOAEC values were 560 and 1000 ng/L, respectively. There are
uncertainties associated with the results of this study because the test material was
reported as being unstable in the water and the test concentration in the exposure
solutions were not measured during the test. The endpoints are based on nominal
concentrations. Risk may be underestimated because measured concentrations were not
provided.
4.1.3 Toxicity to Aquatic Plants
Aquatic plant toxicity studies were used as one of the measures of effect to evaluate
whether captan may affect primary production and the availability of aquatic plants as
food for CRLF tadpoles. Primary productivity is essential for indirectly supporting the
growth and abundance of the CRLF.
Toxicity of captan to nonvascular aquatic plants is based on the green algae, Scenedesmus
subspicatus toxicity study (EC50 = 320 |J,g/L; MRID 00137688) which used nominal
concentrations. There are uncertainties associated with the results of this study because
the endpoints are based on nominal concentrations, risk may be underestimated.
However, RQs were estimated based on this study because it represents the most
conservative toxicity results. In a Selenastrum capricornutum (green algae) toxicity
study, the EC50 = 1770 |J,g/L (MRID 43869809). In an Anabaena flos-aquae (freshwater
algae) toxicity study, the EC50 = 1200 |j,g/L (MRID 44806501). Toxicity of captan to
vascular aquatic plants is based on the duckweed, Lemna gibba toxicity study (EC50 >
12,700 ng/L; MRID 44806503).
4.2 Toxicity of Captan to Terrestrial Organisms
Table 4.03 summarizes the most sensitive terrestrial toxicity endpoints for the CRLF,
based on an evaluation of both the submitted studies and the open literature. A brief
summary of submitted and open literature data considered relevant to this ecological risk
assessment for the CRLF is presented below.
74
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Tsihle 4.03. Torroslrisil Toxicity Profile lor ( siplsin
SiiiTo»;i(e
Spocios
1 n\ici(\ \ iiluo I seel
( iliilion/
MKii)
( oiniiieiils
Direct Effects
Acute Toxicity to Frog
(Terrestrial Phase)
Mallard
Duck
LD50 > 2000 mg/kg bw
(dose)
GS9999-001
Hudson, 1984
Practically non-toxic
Northern
bobwhite
quail
LC50 > 2400 mg/kg diet
(dietary)
MRID
00022923
Hill, 1975
Slightly to practically
non-toxic
Chronic Toxicity to
Frog
(Terrestrial Phase)
Mallard
Duck and
Bobwhite
Quail
NOAEC > 1000 mg/kg
diet
MRID
00098295 and
00098296
Fink, 1980
No affected
endpoints reported
Indirect Effects (Prey Reduction)
Acute Toxicity to
Terrestrial
Invertebrates
Osmia
ligaria
Blue
Orchard Bee
LD50 = 270 ng/bee
Ecotox #
87252
Acute Contact
Toxicity
Acute Toxicity to Rat
Rat
LD50 > 5,000 mg/kg diet
MRID 164355
Practically non-toxic
LD50 = 9,000 mg/kg diet
MRID
00054789
Chronic Toxicity to
Rat
Rat
NOAEL= 250 mg/kg diet
MRID
00125293
Decreases in the
mean litter weights of
pups and sexual
organ atrophy in
adults and pups
Indirect Effects (Habitat Modification)
Acute Toxicity to
Terrestrial Plants
(Wetland)
Acute Toxicity to
Terrestrial Plants
(Upland)
NO APPROPRIATE QUANTITATIVE DATA AVAILABLE
4.2.1 Toxicity to Birds
As specified in the Overview Document, the Agency uses birds as a surrogate for
terrestrial-phase amphibians when amphibian toxicity data are not available (U.S. EPA,
2004). No terrestrial-phase amphibian data are available for captan; therefore, acute and
chronic avian toxicity data are used to assess the potential direct effects of captan to
terrestrial-phase CRLFs.
Captan is practically non-toxic on an oral acute basis for the mallard duck (LD50 >2,000
mg/kg bw) and the Northern bobwhite quail duck (LD50 >2,150 mg/kg bw). Captan is
also practically non-toxic on a sub-acute dietary basis to the mallard duck, Japanese
quail, and ring-necked pheasant (LC50 >5,000 mg/kg diet) and slightly toxic to practically
non-toxic to the Northern bobwhite quail (LC50 >2,400 mg/kg diet). No mortalities
occurred at any dose level tested in the acute avian studies.
75
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The mallard duck and bobwhite quail reproduction studies indicate that exposure at the
three test concentrations of 100, 300, and 1000 mg/kg diet did not affect reproduction
(NOAEC > 1000 mg/kg diet; MRID 00098295, 00098296).
4.2.2 Toxicity to Mammals
Mammalian toxicity data are used to assess potential indirect effects of captan to the
terrestrial-phase CRLF. Direct effects to small mammals resulting from exposure to
captan may also indirectly affect the CRLF via reduction in available food. As discussed
in Section 2.5.3, over 50% of the prey mass of the CRLF may consist of vertebrates such
as mice, frogs, and fish (Hayes and Tennant, 1985).
Captan is practically non-toxic for oral acute toxicity to mammals (LD50> 5,000
mg/kg/diet, MRID 164355). There was one dose tested (5,000 mg/kg diet). Some
mortality was observed in the study. Two males died. One death occurred on day 1 and
one on day 12. One female died on day 4. The deaths were treatment related according to
necropsy. In a previous study, captan was classified as practically non-toxic for oral acute
toxicity to mammals (LD5o= 9,000 mg/kg/diet, MRID 00054789, 1949). The assessment
for CRLF is based on the definitive endpoint (LD50= 9,000 mg/kg/diet).
Chronic studies in rats and rabbits show that captan exposure caused malformation of
nephronic cells in the kidneys (in both males and females), testicular and testes atrophy in
males, vaginal and uterine atrophy in females, decreased body weight gains in both sexes,
reduced ossification in both males and females; sexual organ atrophy in pups (males and
females), and decreased mean litter weights.
For this assessment, the chronic three-generation reproduction toxicity endpoint (NOAEL
= 250 mg a.i./kg diet) for the laboratory rat was used for estimating chronic effects from
captan exposure. Results of the study showed decreases in the mean litter weights of pups
and severe sexual organ atrophy in adults and pups. Additionally, there were also signs
of severe changes in liver weights in the adult males as well as abdominal and intestinal
atrophy. In females, there were signs of stomach atrophy and esophageal atrophy.
4.2.3 Toxicity to Terrestrial Invertebrates
Terrestrial invertebrate toxicity data are used to assess potential indirect effects of captan
to the terrestrial-phase CRLF. Direct effects to terrestrial invertebrates resulting from
exposure to captan may also indirectly affect the CRLF via reduction in available food.
In a registrant submitted acute contact study, the honey-bee, Apis millifera, was exposed
to the technical grade captan and the result was LD50 >10 |j,g/bee. In an additional study,
honeybees were dusted with 215 |Lxg a.i./bee (technical) and there was 9.86% mortality at
48-hours. Captan is categorized as practically non-toxic to non-targeted terrestrial insects
on an acute toxicity basis (MRID # 00113613, 05001991).
76
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The most sensitive terrestrial invertebrate study in the open literature was also reviewed.
In an acute toxicity test, female blue orchard bees (Osmia ligaria) were exposed to the
formulated product, Captan 50WP (48.9% captan). The 72- hour LD50 for acute contact
and oral endpoints were 269.7 and 46.26 |ig a.i./bee, respectively (Ladurner et. al, 2005,
ECOTOX ref # 87252). The 48-hour acute oral LD50 was 100.45 |ig a.i./bee. The 48-
hour acute contact LD50 could not be determined because it was greater than the highest
dose tested. The 72-hour definitive acute contact results were used in the assessment
although it was not the most sensitive because there are several uncertainties in
determining the exposure concentration for the oral endpoint due to lack of information
about allometric relationships between residues and bee ingestion.
4.2.4 T oxi city to T erre stri al PI ants
Terrestrial plant toxicity data are used to evaluate the potential for captan to affect
riparian zone and upland vegetation within the action area for the CRLF. Impacts to
riparian and upland (i.e., grassland, woodland) vegetation may result in indirect effects to
both aquatic- and terrestrial-phase CRLFs, as well as modification to designated critical
habitat PCEs via increased sedimentation, alteration in water quality, and reduction in of
upland and riparian habitat that provides shelter, foraging, predator avoidance and
dispersal for juvenile and adult CRLFs.
Because the Agency waived submission of terrestrial plant toxicity studies for captan,
there are no guideline terrestrial plant toxicity studies submitted for the exposure to
captan to terrestrial vascular and non-vascular plants (U.S. EPA, 1999).
Several papers describing studies evaluating toxicity of captan to plants were found in the
open literature search (ECOTOX). Some papers evaluated the effect of captan seed
treatment on germination rates and seedling growth. A brief summary of some of these
studies is given in Table 4.04. For these studies, application rates were provided in lbs
ai/cwt-seed. None of these papers reported any negative effects of captan on germination
or growth of seedlings. IC^s's could not be calculated as only one application rate was
utilized in each of the studies; although the application rate can be considered aNOAEC.
77
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Table 4.04. Siiiiiinsirv ol'sclcctod KCOTOX papers evaluating cITecl ol'eaplnn seed
treatment on germination ami growth.
I ( (>T<> \
re l av nee
( I'np
\pplicalion rale
kcslllls
|uu4
(McLaren, N. et
al, 1989)
Sorghum
ii 'ii lbs ai c\x l
\o difference mi a\ erage dr\ weight of 25
seedlings 21days after planting.
91168
(Mantecon, J.
D., 1989)
Durum wheat
0.26 lbs ai/cwt
Seedling survival rate higher than control at
all time points (7, 14, 21, 28 days). Seeds
planted in control and treated groups were
infested with Fusarium graminearum.
91007
(Fahim et al,
1983)
Lupin
0.50 lbs ai/cwt
At the end of growing season, average weight
of 100 seeds in the treated group was the
same or greater than in the control. Percent
occurrence of diseased plants was less in
treated group than in control group. Soil in
both groups had been inoculated with
Fusarium oxysporum.
90836
(Davis, M. et al,
2001)
Grain sorghum
0.16 lbs ai/cwt
In greenhouse, increase or no difference in
survival and fresh shoot weight at 28 days
(for either naturally infested soil or
autoclaved soil). It field trial, increase or no
difference in survival (plants/m2) 13-20 days
after planting or in vigor or grain yield 26-72
days after planting.
Some open literature papers evaluating terrestrial plant toxicity were identified in which a
foliar spray was used to apply captan. For a majority of the papers an application rate in
terms of lbs ai/acre could not be determined. It should be noted that for these papers, few
described any lasting phytotoxic effects of the plants.
One paper was identified in ECOTOX in which an application rate in lbs ai/acre could be
determined (Polavarapu, S., 2000, ECOTOX #63909). Two formulations of captan
(Captan 80WP and Captec 4L) were applied to highbush blueberries at 2.5 lbs ai/acre
using a backpack sprayer in six different experiments. Two formulations of diazinon
(Diazinon AG600 and Diazinon 50WP) were also applied alone or in combination with
captan. Phytotoxicity of fruit and foliage clusters were recorded. Applied alone, captan
formulations caused mild phototoxicity (spots) in a small percentage of fruit and leaves;
however, in most cases the injury was superficial and the fruit and leaves recovered by
harvest time. Application of captan and diazinon simultaneously caused greater
phytotoxicity to fruit and leaves than if either chemical was applied alone. The authors
concluded that tank mixes of captan and diazanon should not be recommended on
highbush blueberries, but determined that if applications of the two chemicals were at
least 8 hrs apart, observed phytotoxicity was minimal.
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 individual listed species and
78
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aquatic animals that may indirectly affect the listed species of concern (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 or immobilization) should exposure at the EEC actually occur for a species
with sensitivity to captan 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.
Based on a review of the acute toxicity for captan, no dose response information is
available to estimate a slope for this analysis; therefore, a default slope assumption of 4.5
(with lower and upper bounds of 2 to 9) (Urban and Cook, 1986) is used.
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.
4.4 Incident Database Review
A review of the EIIS database for ecological incidents involving captan was completed
on September 7, 2007. The results of this review for aquatic, terrestrial, and plant
incidents are discussed below in Sections 4.4.1 through 4.4.3, respectively.
4.4.1 Aquati c Inci dents
Two captan incidents have been reported involving aquatic organisms. The first incident,
according to "Summary of Reported DDT, Endrin, and Methyl Parathion Episodes
Involving Fish from 1967 to February, 1975" there was a large fish kill in the state of
New York on May 24, 1972. A spray rig being filled with thiodan and captan overflowed
into a stream, resulting in the death of 10,000 fish (Incident number B000-245-01). The
reported certainty index for the fish incident was categorized as "highly probable"
because although no analytical data were included in the report, it is certain that spillage
of captan concentrate into a stream would be lethal to fish.
The second incident involved a resident of Hendersonville, NC, who complained that fish
were killed in his pond as the result of runoff of pesticides from a neighboring orchard
that was 90 feet away. The orchard is at a higher elevation and, thus, it is possible for
runoff to occur. The orchard owner said that on August 9, 1994, he had applied Lorsban,
Benlate, and Ziram, and on August 22 he had applied Imidan, Topsin-M, and Captan.
Several days after that, a heavy rain occurred and the fish kill took place on August 29
79
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according to the NC Dept of Agri. report. The pond owner said he noticed dead fish on
August 19. The orchard owner had an oxygen test run on the water in the pond on
August 25 but the results were not included in the report. Samples of water, sediment,
soil, and vegetation were taken on September 7 which was considerably after the incident
and they still showed benomyl in the water (9 and 57 ppb). Chlorpyrifos was found in
the soil at concentrations of 35, 50, and 60 ppb, as was Captan (at 310 ppb). Samples of
vegetation in the orchard had chlorpyrifos at 0.74 ppm, phosmet at 7.3 ppm, captan at 2.3
ppm, EBDC at 5.6 ppm, and benomyl at 2.5 ppm. The reported certainty index for the
fish incident (1003826-020) was categorized as "unlikely", because captan was found in
the soil and on the vegetation but not in the water. As compared to the other pesticides,
captan was less likely to be responsible for the incident.
4.4.2 Terrestrial Incidents
Five captan incidents have been reported involving terrestrial organisms, including two
bird and three bee incidents. In the first incident, an estimated 30 to 35 snow geese were
found in a field on the eastern shore of Virginia in Accomack County on January 30,
1985. Necropsies showed aquatic vegetation in the digestive tract but there were no
gross lesions or evidence of infectious diseases. Because empty bags of Vitavax flowable
fungicide were found in the nearby field it was assumed that the birds died of captan
poisoning. The reported certainty index for the bird incident (1004169-006) was
categorized as "probable", because in the absence of analyses of tissue residues it can
only be surmised that the birds died of captan poisoning, since there were empty bags that
had contained this pesticide nearby.
In the second incident, in Hertford, North Carolina, on March 18, 1991, the investigators
alleged that a potato field was treated with aldicarb. The treatment allegedly resulted in a
bird kill. The farmer stated he had used no aldicarb on his potato field, only on tobacco.
He said he used metolachlor on his potatoes. He had dusted potato seeds with captan
before planting. Three soil samples revealed the presence of aldicarb but no other
pesticide. Rain followed the observation of neighbors who observed the aldicarb
application. Witnesses wanted to remain anonymous; this handicapped the investigation.
Stomach content of one seagull revealed inconclusive results because the sample was too
small. Three cats and one dog also suffered mortality during this event. It was
emphasized that the applicator failed to follow packaging guidelines for safe handling of
the pesticide. The NC Ag. Dept. ruled the event a misuse because the labeling of aldicarb
states: "No longer labeled for use on potatoes." The reported certainty index for the bird
incident (1000799-005) was categorized as "unlikely", because captan was not revealed in
the soil analysis and it is unlikely that it played a role in the observed bird mortality.
In a third incident, a bee kill occurred in Hendersonville on July 20, 1993. An
investigation showed that a nearby orchard had been sprayed with Imidan (Phosmet),
Topsin-M, and Captan. Phosmet was found to be present at 0.12 ppm in the bees, but
there was no detection of Captan or Thiophanate methyl. All three of those compounds
were found as residues on the vegetation, with Phosmet at 180 ppm, Captan at 400 ppm
(on apple leaves), and Thiophanate Methyl at 57 ppm. The reported certainty index for
80
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the bee incident (1003654-016) was categorized as "unlikely", because captan was not
found in the bees.
In the forth incident, a bee keeper in Hendersonville, NC, complained that some of his
bees died on August 14, 1994. The closest orchards were two miles away and they had
been sprayed on August 3 or 4 with methyl parathion, chlorpyrifos, and Benlate. A
sample of the dead bees, taken on August 15, contained methyl parathion at 0.77 ppm.
Samples of vegetation taken at the orchards on August 18 (a little more than two weeks
after the spraying) contained methyl parathion, chlorpyrifos, and captan. Methyl
parathion was the cause of the bee kill. No violations were charged. The reported
certainty index for the bee incident (1003826-027) was categorized as "unlikely", because
captan was not found in the bees.
In the fifth incident, a bee keeper in Hendersonville, NC, asked the NC Dept. of
Agriculture to determine the cause of his bees' death. Accordingly the Ag. representative
interviewed farmers in the surrounding area and learned that a variety of products had
been used, but none admitted to spraying Penncap M, which is what the bee keeper
suspected as being the cause of the incident. On April 18, 1995 Polyram and Nova
(maneb, myclobutanil) were sprayed; on April 27, Sevin (carbaryl) was sprayed; on April
29 Phaser, Polyram, and Rubigan were sprayed (endosulfan, maneb, fenarimol); on April
18 a second farmer applied Polyram and Nova; on April 19 Captan and Rubigan
(fenarimol) were sprayed along with sulfur. Dead bees were noticed on April 28 and
some were collected for analysis on May 1, at which time various samples of vegetation
were also taken. The dead bees contained 3.1 ppm methyl parathion, 0.10 ppm
chlorpyrifos, dimethoate and metabolite (1.7 ppm), and endosulfan and metabolite (0.20
ppm). Vegetation from the nearby orchards contained various amounts of chlorpyrifos,
captan, dimethoate, endosulfan, and carbaryl but no methyl parathion. The conclusion of
the Dept. of Agriculture was that it could not identify the source of the methyl parathion
which probably was mainly responsible for the bee deaths. The reported certainty index
for the bee incident (1003826-009) was categorized as "unlikely", because captan was not
found in the bees.
4.4.3 PI ant Inci dents
Two captan incidents have been reported involving terrestrial plants. In the first incident,
Gustafson LLC reported that there was an error by a formulator who added tebuconazole,
an antimicrobial, to a 790 gallon lot of the fungicide Rival (Pentachloronitrobenzene
[PCNB], thiabendazol, captan). This created a formulation of an unregistered end-use
product for soybean seed treatment. About 403 gallons of this lot was sold to and used by
10 commercial seed treating companies for soybeans. The material was used in IL, IN,
OH, MI and LA. Gastafson was notified on May 21, 2004 of stunting growth. The seed
treating companies were notified and instructed to notify the growers to destroy their
crops. The reported certainty index for the soybean incident (1015152-001) was
categorized as "possible" for all four listed pesticides, because the damage was probably
due to the accidental misuse of the pesticides involved. It could not be determined if an
individual pesticide or some combination caused the stunted growth.
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The second plant incident involved damage to apples. In order to comply with 6(a)2
regulations, Zeneca reported a complaint from North East, PA, that Abound (active
ingredient of azoxystrobin) had damaged his apples. In his deposition, the grower
admitted that he had sprayed grapes with parathion, captan, and Stop-It [a calcium
supplement] prior to spraying the apples and may not have completely washed out the
tank before adding Abound. The worst damage occurred with the first tank full of
pesticide suggesting that the pesticides used on the grapes were responsible for the
damage. However, Abound is not registered for use on apples and, therefore, must be
suspected as a cause of the problem. The current label for Abound states "Abound is
extremely phytotoxic to certain apple varieties. AVOID SPRAY DRIFT. Extreme care
must be used to prevent injury to apple trees (and apple fruit). DO NOT spray Abound
were spray drift may reach apple trees." The reported certainty index for the apple
incident (1009314-002) was categorized as "possible" for all the involved pesticides, due
to the misuse of the pesticides involved. It could not be determined if an individual
pesticide or some combination caused the plant damage.
5. Risk Characterization
Risk characterization is the integration of the exposure and effects characterizations to
determine the potential ecological risk from varying captan use scenarios within the
action area and likelihood of direct and indirect effects on the CRLF and its designated
critical habitat. The risk characterization provides an estimation (Section 5.1) and a
description (Section 5.2) of the likelihood of adverse effects; articulates risk assessment
assumptions, limitations, and uncertainties; and synthesizes an overall conclusion
regarding the likelihood of adverse effects to the CRLF and/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 C). For acute exposures to the
CRLF and its animal prey in aquatic habitats, as well as terrestrial invertebrates, the non-
listed acute risk LOC is 0.5, the non-listed acute restricted use LOC is 0.1, and the
endangered species LOC is 0.05. For acute exposures to the CRLF and mammals, the
non-listed acute risk LOC is 0.5, the non-listed acute restricted use LOC is 0.2, and the
endangered species 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 captan use
information summarized in Tables 3.04 - 3.06 and the appropriate aquatic toxicity
endpoint from Table 4.02. Risks to the terrestrial-phase CRLF and its prey (e.g.
terrestrial insects, small mammals and terrestrial-phase frogs) are estimated based on
82
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exposures resulting from foliar and seed applications of captan (Tables 3.09 - 3.11) and
the appropriate toxicity endpoint from Table 4.03. Exposures are also derived for
terrestrial plants are discussed qualitatively due to lack of data.
5.1.1 Exposures in the Aquatic Habitat
Risk quotients were calculated based on the screening level aquatic EECs for captan
based on foliar spray application for the food uses, foliar spray on turf and ornamentals,
and seed treatment to food and non-food uses. In cases where LOCs were not exceeded
based on the maximum application rate, additional RQs were not derived because it was
assumed that RQs for lower EECs would also not exceed LOCs. However, if LOCs were
exceeded based on the highest EECs, use-specific RQs were also derived.
5.1.1.1. Direct Effects to Aquatic-Phase CRLF
Direct effects to the aquatic-phase CRLF are based on peak EECs in the standard pond
and the lowest acute toxicity value for freshwater fish. In order to assess direct chronic
risks to the CRLF, 60-day EECs and the lowest chronic toxicity value for freshwater fish
are used. As shown in Table 5.01, acute LOCs (0.05) are exceeded for all foliar
application to food uses (RQs range from 0.053 - 0.823). As a lower bound to estimated
risk based on the food uses, RQs were calculated for one application to almond (crop
which resulted in the highest EECs). Acute LOCs were exceeded based on one
application (RQ = 0.53) and four applications (RQ = 0.823) for almond. In addition,
acute LOCs were exceeded for foliar application to turf use at two applications (RQ =
0.466) and ornamentals at 26 applications (RQ = 1.09) both uses have the same
application rate (4.5 lb a.i./A). The highest screening-level aquatic EEC for seed
treatment for the food uses (based on use of captan on wheat at 0.169 lbs ai/A) was
initially used to derive risk quotients. Acute LOCs are not exceeded for seed treatment
for the food uses with the most conservative assumption of no incorporation; therefore,
additional RQs were not derived because it was assumed that RQs for lower EECs would
also not exceed LOCs. Acute LOCs are exceeded for grasses grown for seed (RQ =
0.155) and ornamental seedbed use (RQ = 0.597). Chronic LOCs are not exceeded for all
of the proposed uses. The preliminary effects determination is "may affect", based on
direct effects to aquatic-phase CRLFs on an acute basis for foliar application of captan to
food and ornamental/turf uses and non-food seed treatments.
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Table 5.01. Uisk Quotient values lor acute ami chronic exposures to (apian lor
Direct KITects to the (KIT (aquatic p
lase) haset
on I'isli toxicity.
Uses
Application #
Peak EEC
60 day
Direct
Direct
and type
(Mg/L)
EEC
(Hg/L)
effects Acute
RQ1
effects
Chronic
RQ2
Almond (4 applications)
Aerial
21.567
0.591
0.823***
0.036
Ground
11.995
0.219
0.458**
0.013
Almond (1 application)
Aerial
13.853
0.145
0.529***
0.009
Strawberry
Aerial
8.396
0.652
0.320**
0.040
Ground
2.793
0.151
0.107**
0.009
Ginseng
Aerial
5.597
0.415
0.214**
0.025
Ground
1.119
0.083
0.043
0.005
Orchard ( nips
Apple
Aerial
11.190
0.828
0.427***
0.050
Ground
2.239
0.166
0.085*
0.010
Apricot
Aerial
6.998
0.326
0.267**
0.020
Ground
1.400
0.065
0.053*
0.004
Cherry
Aerial
5.597
0.389
0.214**
0.024
Ground
2.628
0.098
0.100**
0.006
Nectarine
Aerial
11.200
0.625
0.427**
0.038
Ground
2.239
0.125
0.085*
0.008
Peach
Aerial
11.200
0.832
0.427**
0.050
Ground
2.239
0.166
0.085*
0.010
Plum/ Prune
Aerial
8.396
0.700
0.320**
0.042
Ground
1.679
0.400
0.064*
0.024
\ ine>ard Crops
Blackberry/ Caneberry /
Aerial
5.597
0.269
0.214**
0.016
Raspberry/ Loganberry
Ground
1.127
0.060
0.043
0.004
Blueberry
Aerial
10.166
0.634
0.388**
0.038
Ground
5.331
0.165
0.203**
0.010
Dewberry
Aerial
8.816
0.271
0.336**
0.016
Ground
2.317
0.075
0.088*
0.005
Grapes
Aerial
5.598
0.323
0.214**
0.020
(i round
1 i:u
nii'l
o o41
o 004
Seed Trcalmenl
Wheal
\o
Incorporation
u 514
0 005
0.0211
o oo|
Grass/Forage/Fodder/Hays
grown for seed
2 inch incorp.
4.049
0.040
0.155**
0.002
Ornamental lawn seedbed
3 inch incorp.
15.639
0.153
0.597***
0.009
Non-Food Uses
Golf Course Turf/ Sod
Aerial (2 appl)
12.215
0.256
0.466**
0.016
Farm/ Dichondra Grass
Ground (2 appl)
3.605
0.077
0.138**
0.005
Ornamental Grasses (non-
Aerial (26 appl)
27.474
1.093
1.049***
0.066
pasture areas)
Ground (26
appl)
28.571
0.298
1.090***
0.018
1 Based on Acute Toxicity to Brown Trout LC50= 26.2 |ig/L (MRID 40098001)
2 Based on Chronic Toxicity to Fathead minnow NOAEC= 16.5 |ig/L (MRID 00057846)
*** Exceeds Acute Risk LOC for birds (RQ> 0.5), in bold
** Exceeds Acute Restricted LOC for birds (RQ> 0.2), in bold
* Exceeds Acute Endangered Risk LOC for birds (RQ> 0.1), in bold
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5.1.1.2 Indirect Effects to Aquatic-Phase CRLF via Reduction in Prey (non-
vascular aquatic plants, aquatic invertebrates, fish, and frogs)
Non-vascular Aquatic Plants
Indirect effects of captan to the aquatic-phase CRLF (tadpoles) via reduction in non-
vascular aquatic plants in its diet are based on peak EECs from the standard pond and the
lowest acute toxicity value for aquatic non-vascular plants. The highest screening-level
aquatic EEC for the food uses (based on use of captan on almonds at 4.5 lbs ai/A with 4
applications and 7-day intervals) and ornamental uses were initially used to derive risk
quotients. Acute risk LOC (RQ>1.0) were not exceeded based on these use patterns,
therefore, additional RQs were not derived because it was assumed that RQs for lower
EECs would also not exceed LOCs (Table 5.02). The effects determination is "no
effect", for indirect effects to aquatic-phase CRLFs based on a reduction in non-vascular
aquatic plants as food items.
Table 5.02. Uisk Quotient values lor exposures ol' parent Captan to unicellular
aquatic plants lor Indirect K fleets (diet ol'CKI.I-' in tadpole lile stage)
Uses
Application # and type
Peak EEC (jig/L)
Indirect effects
Non-endangered RQ1
Almond
Aerial
21.567
0.067
Ground
11.995
0.037
Non-l-'ood I sos
Golf Course Turf/ Sod
Farm
Aerial (2 applications)
12.215
0.038
Ground (2 applications)
3.605
0.011
Ornamental Grasses
(non-pasture areas)
Aerial (26 appl)
27.474
0.086
Ground (26 appl)
28.571
0.089
1 Based on green algae (Scenedesmus subspicatus) EC50 = 320 ng/L (ACC 252586)
+ Exceeds Non-endangered Aquatic Plant LOC (1.0)
Aquatic Invertebrates
Indirect acute effects to the aquatic-phase CRLF via effects to prey (invertebrates) in
aquatic habitats are based on 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 toxicity value for invertebrates are used to derive RQs. The highest screening-
level aquatic EEC for the food uses (based on use of captan on almonds at 4.5 lbs ai/A
with 4 applications and 7-day intervals) was initially used to derive risk quotients. Acute
and chronic risk LOCs were not exceeded based on this use pattern, therefore, additional
RQs were not derived (including seed treatment) because it was assumed that RQs for
lower EECs would also not exceed LOCs. In addition, acute and chronic LOCs were not
exceeded for all modeled ornamental and turf non-food uses. 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 5.03. The effects determination is "no effect" for indirect
effects to aquatic-phase CRLFs based on a reduction of freshwater invertebrates as prey
(via direct acute toxicity to freshwater invertebrates) for all modeled uses.
85
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Table 5.03. Uisk Quotient values lor exposures ol' parent Captan to Aquatic
Invertebrates(1
)aphni(l) lor Iik
irect KITects (prey-base of CUIT")
Uses
Application #
Peak EEC
21 day EEC
Indirect effect
Indirect effect
and type
(Ug/L)
(Ug/L)
Acute RQ
Chronic RQ
Almond
Aerial
21.567
1.552
0.003
0.002
Ground
11.995
0.640
0.001
0.001
Non-Food Uses
Golf Course Turf/
Aerial (2 appl)
12.215
0.732
0.001
0.001
Sod Farm
Ground (2 appl)
3.605
0.220
<0.001
<0.001
Ornamental
Aerial (26 appl)
27.474
1.194
0.003
0.002
Grasses (non-
Ground (26 appl)
28.571
0.761
0.003
0.001
pasture areas)
1 Based on Acute Toxicity to Daphnid EC50= 8400 ug/L (MRID GSO120041)
2 Based on Chronic Toxicity to Daphnia NOAEC= 560 ug/L (MRID 441488-01)
Fish and Frogs
Fish and frogs also represent prey of the CRLF. RQs associated with acute and chronic
direct toxicity to the CRLF (Table 5.01) are used to assess potential indirect effects to the
CRLF based on a reduction in freshwater fish and frogs as food items. Given that acute
RQs for direct toxicity to the CRLF exceed non-listed acute risk LOCs, the preliminary
effects determination is "may affect", based on indirect effects as a reduction of fish and
frogs as prey items for foliar application of captan to food and ornamental/turf uses.
5.1.1.3. Indirect Effects to CRLF via Reduction in Habitat and/or Primary
Productivity (Freshwater Aquatic Plants)
Indirect effects to the CRLF via direct toxicity to aquatic plants are estimated using the
most sensitive non-vascular and vascular plant toxicity endpoints. Because there are no
obligate relationships between the CRLF and any aquatic plant species, the most sensitive
EC50 values, rather than NOAEC values, were used to derive RQs. As shown in Table
5.04, none of the RQs exceed the LOC of 1 for vascular aquatic plants. In addition, as
previously discussed in Section 5.1.1.2 and summarized in Table 5.02, LOCs are not
exceeded for non-vascular aquatic plants for all captan uses. Therefore, the preliminary
effects determination is "no effect", based on indirect effects to habitat and/or primary
productivity for the aquatic-phase CRLF for use of captan.
Table 5.04. Uisk Quo
plants for Indirect V.
ticnl values for exposures of parenl Captan to vascular aquatic
Teds (habitat of aquatic-phase CUM' )
Uses
Application # and type
Peak EEC Qig/L)
Indirect effects
Non-endangered RQ1
Almond
Aerial
21.567
<0.002
Ground
11.995
<0.001
Non-l-'ood I ses
Golf Course Turf/ Sod
Farm
Aerial (2 applications)
12.215
<0.001
Ground (2 applications)
3.605
<0.001
Ornamental Grasses
(non-pasture areas)
Aerial (26 applications)
27.474
0.002
Ground (26 applications)
28.571
0.002
1 Based on duckweed (Lemna gibba) EC50 > 12,700 ug/L (MRID 448065-03)
+ Exceeds Non-endangered Aquatic Plant LOC (1.0)
86
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5.1.2 Exposures in the Terrestrial Habitat
5.1.2.1 Direct Effects to Terrestrial-phase CRLF
To assess risks of captan to terrestrial-phase CRLF, dietary-based and dose-based
exposures modeled in T-REX for a small bird (20 g) and medium (100 g) bird, which are
used as a surrogate for juvenile and adult terrestrial-phase amphibians, respectively, are
used. Exposure is based on the consumption of small insects. Acute, subacute and chronic
effects are estimated using the lowest available toxicity data for birds. EECs are divided
by toxicity values to estimate acute and chronic dietary-based RQs as well as dose-based
RQs.
Acute dose and dietary-based RQ values, and chronic dietary-based RQ values exceed
the LOC for the frog for all uses based on the screening level estimate using T-REX,
however these RQs are non-definitive and represent an upper bound of the risk (Table
5.05). Definitive acute RQ values for terrestrial-phase CRLFs could not be derived
because the acute avian effects data show no mortality to the mallard duck (LD50 >2,000
mg/kg bw) and the Northern bobwhite quail duck (LD50 >2,150 mg/kg bw). Although
definitive dose-based RQs cannot be determined, upper bound RQs were estimated. The
predicted acute dose-based EECs (2655 - 4033 ppm based on use on peach) are about
four times the adjusted LD50 values for juvenile terrestrial-phase CRLFs (1038 mg/kg-
bw).
In addition, the dietary-based LC50 value for the mallard duck, Japanese quail, and ring-
necked pheasant (LC50 >5,000 mg/kg diet) and Northern bobwhite quail (LC50 >2,400
mg/kg bw) also indicates no mortality at the highest test concentration. The predicted
acute dietary-based EECs (2331 - 3542 ppm) also exceed the 2400 mg/kg diet (dietary)
test levels. However, the dietary EECs do not exceed the LC50 value for the mallard duck,
Japanese quail, and ring-necked pheasant (LC50 >5,000 mg/kg diet).
The mallard duck and bobwhite quail reproduction studies indicate that exposure at the
three test concentrations of 100, 300, and 1000 mg/kg diet did not affect reproduction
(NOAEC > 1000 mg/kg diet). The predicted dietary-based EECs (2331 - 3542 ppm) also
exceed these test levels. Effects to birds, and therefore terrestrial-phase CRLF, are
unknown at such increased exposure levels. Thus, the RQs calculated based on these
endpoints are an upper bound estimate. RQs for a definitive endpoint would be lower,
but how much lower cannot be determined from this study.
87
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Table 5.05. Acute and chronic, dietary-based UQs and dose-based UQs based on
TUK\ lor direct effects lo (lie terrestrial-phase ('UI.I-" (UQs bracketed between
foliar dissipation hall'lives of 10 and 35 days). 1
I SO
Acule Dose -li.ised RQ (food -
sm;iII insects)
Acule Dicl;iscd
no
Sniiill Insccls
Chronic l)icl;in -
li.iscd UO
Sni;ill Insccls
20 li birds
100 » birds
Caneberry
<0.57-<1.04***
<0.26-<0.46**
<0.22-<0.39 **
<0.52 - <0.94
Peach
<2.56- <3.88***
<1.15—<1.74***
<0.97-<1.48 ***
<2.33-<3.54 +
Wheat
<0.30**
—
—
<1.25 +
Golf Course
Turf/ Sod Farm/
Dichondra
grasses
<1.03—<1.19 ***
<0.46— <0.53***
<0.39-<0.45 **
<0.94-<1.09 +
Ornamental
grasses
<1.66-<4.78 ***
<0.74-<2.14***
<0.63 -<1.82 ***
<1.51-<4.36 +
1 Avian toxicity tests used to evaluate the terrestrial phase frog did not establish a definitive endpoint (i.e.,
the value was greater than the highest concentration tested), thus these RQ values represent an upper bound
*** Exceeds Acute Risk LOC for birds (RQ> 0.5)
** Exceeds Acute Restricted LOC for birds (RQ> 0.2)
* Exceeds Acute Endangered Risk LOC for birds (RQ> 0.1)
+ Exceeds Chronic Risk LOC for birds (RQ> 1.0)
Because RQs for the surrogate for terrestrial phase frogs exceeded the LOCs for all
application rates, the T-HERPS model was used to better evaluate potential dose-based
risk. T-HERPS is a modification of T-REX which includes amphibian/reptile specific
allometric equations, weight classes appropriate for the CLRF, and prey items specific to
the CLRF. T-HERP groups the frogs into three classes: small (1.4g), medium (37g), and
large (238g). The two smaller weight classes most closely approximate the 20g juvenile
that exceeded LOCs using the T-REX model.
Based on T-HERPS, the refined dose-based RQs do not exceed the endangered species
acute risk LOCs for all of the frog weight classes consuming insects. Acute dose-based
LOCs are exceeded for direct effects for large frogs (238 grams) consuming small
herbivorous mammals based on captan use on peaches (upper bound) (Table 5.06).
Because acute dietary-based and chronic LOCs are exceeded for the frogs, the
preliminary effects determination for direct acute effects to the terrestrial-phase CRLF is
"may affect".
88
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Table 5.06. Refilled acute dose-based UQs lor direct effects to the terrestrial-phase
CULK. based on 10-dav foliar dissipation half-life, calculated using T-l IK UPS. 1
l-'ood
Dose ISiisod KQ
1.4 ( Kl.l
Dose liiisi-ri KQ
r»( ki.i
Dose liiiscri KQ
23S si < Kl.l
( iinohorn
IViicli
( iinohorn
IViicli
( iinohorn
IViicli
Small Insects
<0.01
<0.05
<0.01
<0.04
<0.01
<0.03
Large Insects
<0.01
<0.01
<0.01
<0.01
<0.01
<0.01
Small
Herbivore
mammals
NA
NA
<0.05
<0.20**
Small
Insectivore
mammals
NA
NA
<0.01
<0.01
Small
Terrestrial-
phase
Amphibians
NA
NA
<0.01
<0.01
1 Avian toxicity tests used to evaluate the terrestrial phase frog did not establish a definitive endpoint (i.e.,
the value was greater than the highest concentration tested), thus these RQ values represent an upper bound
** Exceeds Acute Restricted LOC and Acute Endangered Risk for birds (RQ> 0.2), in bold
NA Not Applicable (size class of frog too small to consume mammals and amphibians)
5.1.2.2. Indirect Effects to Terrestrial-Phase CRLF via Reduction in Prey
(terrestrial invertebrates, mammals, and frogs)
5.1.2.2.1 Terrestrial Invertebrates
In order to assess the risks of foliar applications of captan to terrestrial invertebrates,
which are considered prey of CRLF in terrestrial habitats, the blue orchard bee (Osmia
lignaria) was used as a surrogate for terrestrial invertebrates. The acute contact LD50 =
270 |ig a.i./bee (Osmia lignaria) was converted to ppm units using the weight of an adult
honey bee (1 bee/0.128g) resulting in LD50 = 2107 |ig a.i./g of bee. Female orchard bees
were used in the acute contact toxicity study which are approximately the same size as
the honey bee (Bosch and Kemp, 2001). EECs (in ppm which is equal to |ig a.i./g of bee)
were calculated in T-REX and based on residues on small and large insects. The resulting
RQ values for large insect and small insect exposures bound the potential range of
exposures for terrestrial insects to captan. The RQ values exceed the LOC (RQ>0.05) for
both large and small terrestrial insects for all uses (Table 5.07). The preliminary effects
determination for indirect effects to terrestrial-phase CRLFs via reduction in terrestrial
invertebrates as dietary food items is "may affect".
89
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Table 5.07. Summary of UQs I sed lo Kstimalc Indirect KITeds lo (lie Terrestrial-
pliase CUM'" via Direct K fleets on Terrestrial Invertebrates as Dietary Kood
llenis (UQs bracketed l\v foliar dissipation hall-lives 10 - 35 days)
I SO
Sniiill Insert RQ
l.iiriio Insert UQ
Caneberry (Lowest food use)
0.25 - 0.45 *
0.03 - 0.05 *
Peach (Highest food use)
1.11 - 1.68 *
0.123-0.187*
Golf Course Turf/ Sod Farm/ Dichondra
grasses
(4.3 lb a.i./A, 2 appl, 7-day)
0.45 - 0.52 *
0.05 - 0.06 *
Ornamental grasses
(4.3 lb a.i./A, 26 appl, 7-day)
0.72 - 2.07 *
0.08 - 0.23 *
* Exceeds terrestrial insect LOC (RQ > 0.05)
5.1.2.2.2a 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. EECs are divided by the toxicity value to estimate
acute and chronic dose-based RQs as well as chronic dietary-based RQs. Indirect effects
to terrestrial-phase CRLFs via direct acute effects to small mammals as prey items are
evaluated using the acute toxicity data (LD50= 9,000 mg/kg/diet, MRID 00054789).
For this assessment, the chronic three-generation reproduction toxicity endpoint (NOAEL
= 250 mg a.i./kg diet) for the laboratory rat was used for estimating chronic effects from
captan exposure. Results of the study showed decreases in the mean litter weights of pups
and severe sexual organ atrophy in adults and pups.
Risk quotients were calculated for the food use with the lowest application rate
(caneberry) and the highest application rate (peach). Risk quotients were calculated based
on both a 10-day and 35-day foliar dissipation half-life. Acute dose-based, acute dietary-
based and chronic dietary based LOCs were exceeded for all foliar applications (Table
5.08). Acute LOCs were not exceeded for captan applied as a seed treatment. The
preliminary effects determination for indirect effects to terrestrial-phase CRLFs via
reduction in small mammals as dietary food items is "may affect".
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Table 5.0S. Siimiliary of Acute1 and Chronic2 KQs to Kslimatc Indirect K fleets to the
Tcrrcslrial-phasc CUM'" via Direct Kfleets 011 Small .Mammals as Dietary f ood Items.
KQs bracketed bv foliar dissipation half-lives 10 - 35 davs.
I SO
(Application Ksilc)
Doso-hiisod Acute UQ1
Dosc-bnscd
Chronic RQ:
Dicliin-hiiscd
Chronic UQ:
Caneberry (Lowest food use)
0.04-0.08
32.27 - 58.27 +
3.72 - 6.72 +
Peach (Highest food use)
0.20 - 0.30 **
144 - 219 +
16.58 - 25.18 +
Wheat - Seed Treatment
0.01
5.00 +
Golf Course Turf/ Sod Farm/
Dichondra grasses
(4.3 lb a.i./A, 2 appl, 7-day)
0.08-0.09
57.86 - 66.99 +
6.67 - 7.72 +
Ornamental grasses
(4.3 lb a.i./A, 26 appl, 7-day)
0.13*-0.37 **
93.16-269 +
10.74 - 31.02 +
* Exceeds Acute Risk mammalian LOC (RQ >0.1)
** Exceeds Acute Restricted Risk mammalian LOC (RQ > 0.2)
+ Exceeds mammalian chronic LOC (RQ > 1)
1 Based on dose-based EEC and rat LD50 = 9000 mg/kg-diet (MRID 00054789)
2 Based on dietary-based EEC and rat NOAEC = 250 mg/kg-diet (MRID 00125293)
5.1.2.2.3 Frogs
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. As previously
discussed in Section 5.1.2.1, direct acute effects to frogs are possible but the risk
quotients are non-definitive, based on the available avian acute toxicity data. Acute and
chronic RQ values exceed the LOC for all modeled uses of captan (Table 5.05).
Therefore, the preliminary effects determination for indirect effects to terrestrial-phase
CRLFs via reduction in other species of frogs as dietary food items is "may affect".
5.1.2.3. Indirect Effects to CRLF via Reduction in Terrestrial Plant Community
(Riparian and Upland Habitat)
Potential indirect effects to the CRLF resulting from direct effects on riparian and upland
vegetation are typically assessed using RQs from terrestrial plant seedling emergence and
vegetative vigor EC25 data as a screen. No guideline terrestrial plant toxicity data for
captan were submitted to the Agency. Using open literature studies obtained from
ECOTOX, it was not possible to determine endpoints analogous to the seedling
emergence or vegetative vigor EC25. No RQ calculations were performed; however,
EECs were calculated for the highest single foliar application rate of 4.5 lbs ai/acre using
TERRPLANT (Appendix K). EECs for spray drift alone, total for dry areas, total for
semi-aquatic areas are 0.23, 0.27, and 0.68 lbs ai/acre.
Based on open literature data identified by ECOTOX, captan as a seed treatment did not
negatively impact germination or growth of the evaluated plant species (Section 4.2.4).
Application rates were provided in lbs ai/cwt-seed; exposure estimation in units suitable
for TERRPLANT (i.e., lbs ai/acre) could not be determined for any of these studies.
Individual seed exposure to captan was high as seeds were coated with captan by shaking
seeds and pesticide in a closed container. This exposure is likely to be higher than
91
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expected exposure due to spray drift and runoff after application in the field. None of the
reviewed papers reported any negative effects of captan on germination or growth of
seedlings. The results of these studies were considered qualitatively in lieu of a seedling
emergence study.
Based on ECOTOX data, there is the potential that terrestrial plants may be impacted by
foliar application of captan. In one study (#63909), highbush blueberries showed mild
phytotoxic effects at an application rate of 2.5 lbs ai/acre (foliar application rates for
captan range from 2.0 to 4.5 lbs ai/acre). It is unknown where highbush blueberries fall in
the species sensitivity distribution for dicots or terrestrial plants in general. The results of
this test indicate that a variety of terrestrial plants that may inhabit riparian and upland
zones may be sensitive to captan exposure. However, the EECs estimated by
TERRPLANT (0.23 - 0.68 lb a.i./A) are much less than the exposure causing mild
phytotoxic effects to blueberries in the study.
The preliminary effects determination for indirect effects to terrestrial- and aquatic-phase
CRLFs via reduction in the terrestrial plant community is "may affect".
5.1.3 Primary Constituent Elements of Designated Critical Habitat
5.1.3.1 Aquatic-Phase (Aquatic Breeding Habitat and Aquatic Non-Breeding
Habitat)
Three of the four assessment endpoints for the aquatic-phase primary constituent
elements (PCEs) of designated critical habitat for the CRLF are related to potential
effects to aquatic and/or terrestrial plants:
• 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.
• 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.
• Reduction and/or modification of aquatic-based food sources for pre-metamorphs
(e.g., algae).
The preliminary effects determination for aquatic-phase PCEs of designated habitat
related to potential effects on aquatic plants is "no effect", based on the risk estimation
provided for aquatic vascular and non-vascular plants described in Sections 5.1.1.2 and
5.1.1.3. The preliminary effects determination for aquatic-phase PCEs of designated
habitat related to potential effects on terrestrial plants is "may affect", based on the risk
estimation described in Sections 5.1.1.2 and 5.1.2.3.
The remaining aquatic-phase PCE is "alteration of other chemical characteristics
necessary for normal growth and viability of CRLFs and their food source." To assess
92
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the impact of captan on this PCE, acute and chronic freshwater fish and invertebrate
toxicity endpoints, as well endpoints for aquatic non-vascular plants, are used as
measures of effects. RQs for these endpoints were calculated in Sections 5.1.1.1 and
5.1.1.2. Based on these results, the preliminary effects determination for alteration of
characteristics necessary for normal growth and viability of the CRLF is "may affect"
(see Section 5.1.1.1). However, aquatic invertebrate and non-vascular aquatic plant food
items of the CRLF are not affected; therefore the preliminary effects determination for
potential impacts to these food items is "no effect" (see Section 5.1.1.2).
5.1.3.2 Terrestrial-Phase (Upland Habitat and Dispersal Habitat)
Two of the four assessment endpoints for the terrestrial-phase PCEs of designated critical
habitat for the CRLF are related to potential effects to terrestrial plants:
• 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
• 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
The preliminary effects determination for terrestrial-phase PCEs of designated habitat
related to potential effects on terrestrial plants is "may affect", based on the risk
estimation provided in Section 5.1.2.3.
The third terrestrial-phase PCE is "reduction and/or modification of food sources for
terrestrial phase juveniles and adults." To assess the impact of captan on this PCE, acute
and chronic toxicity endpoints for birds, mammals, and terrestrial invertebrates are used
as measures of effects. RQs for these endpoints, which were calculated in Section
5.1.2.2, exceed the LOCs for all captan uses. Captan is expected to cause direct effects to
terrestrial invertebrate and frog prey items of the terrestrial-phase CRLF. The
preliminary effects determination for adverse habitat modification via impacts of captan
uses to terrestrial-phase CRLF food items is "may affect".
The fourth terrestrial-phase PC is based on alteration of chemical characteristics
necessary for normal growth and viability of juvenile and adult CRLFs and their food
source. Direct acute effects, via mortality, may be affected for the terrestrial-phase CRLF
(see Section 5.2.1.2). Therefore the preliminary effects determinations for adverse
habitat modification is "may affect" via direct acute effects to terrestrial-phase CRLFs.
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5.1.4 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. The use map (Figure 7) shows the extent of orchard/vineyard,
agricultural (including ornamentals), and turf land cover which represent the labeled uses
for captan in California. The initial area of concern is defined as the land cover types and
the initial stream reaches (Figure 8). The screening level risk assessment will define
which taxa, if any, are predicted to be exposed at concentrations above the Agency's
Levels of Concern (LOC). LOC exceedances are used to describe how far effects may be
seen from the initial area of concern. The final action area includes the terrestrial action
based on the buffered area from the spray drift analysis and the aquatic action area based
on the downstream extent (Figure 9).
5.1.4.1. Downstream Aquatic Areas affected by the federal action
In order to determine the extent of the action area in aquatic habitats, the agricultural
(including ornamentals), orchard/vineyard, and turf uses resulting in the greatest ratios of
the RQ to the LOC for any endpoint for aquatic organisms is used to determine the
distance downstream for concentrations to be diluted below levels that would be of
concern {i.e. result in RQs above the LOC). The downstream dilution for all uses is based
on direct effects to the CRLF through acute effects to fish (LOC = 0.05) exposed to
captan in runoff. Downstream analysis for the agriculture land use type is based on
ornamental grasses at 4.3 lb a.i./A with 26 applications with a 7-day interval (RQ = 1.09)
because it has the greatest ratio of 21.80. Downstream analysis for the orchard/vineyard
land use type is based on almond at 4.5 lb a.i./A with 4 applications with a 7-day interval
(RQ = 0.823) because it has the greatest ratio of 16.46. Downstream analysis for the turf
land use type is based on golf courses at 4.3 lb a.i./A with 2 applications with a 7-day
interval (RQ = 0.466) because it has the greatest ratio of 9.32. The areas indirectly
affected by the federal action due to runoff of captan to aquatic habitats are depicted in
Figure 9 (Section 2.7). The total stream kilometers within the action area that are at
levels of concern are defined in Table 5.09.
Table 5.09. Aquatic spatial summary results lor agricultural (including
ornamentals), orchard/vineyard and lurl'land use tvpes.
Mo;isiiiv
Aui'iciilluiv
()rch;inl/\ inc\;ird
im-r
lolal California blieani kilomeleib
332,902
Total stream kilometers in initial area of
concern
57,087
11,946
19,939
Total stream kilometers added downstream
3,580
1,477
765
Total stream kilometers in final action area
60,667
13,423
20,704
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5.1.4.2. Terrestrial Areas affected by the federal action
When considering the terrestrial habitats of the CRLF, spray drift from use sites onto
non-target areas could potentially result in exposures of the CRLF, its prey and its habitat
to captan. Therefore, it is necessary to estimate the distance from the application site
where spray drift exposures do not result in LOC exceedances for organisms within the
terrestrial habitat.
Since spray drift is the most likely means through which non-target terrestrial organisms
will be potentially exposed to captan, the AGDISP model (version 8.13) is used to
estimate the terrestrial distance from the site of application to where RQs are predicted to
fall below the endangered species LOC as described in Section 3.2.3. The highest single
maximum application rate allowed on the label for captan uses was modeled to determine
the maximum potential off-site estimated environmental concentrations (EECs) for a
single application based on upper bound Kenaga values. The highest single maximum
application rate was determined for each land use type including agriculture (includes
ornamentals), orchard/ vineyard and turf. Almond is the orchard/vineyard crop with the
highest application rate with a single application of 4.5 lb a.i./acre. Ornamental grasses is
the agriculture crop with the highest application rate with a single application of 4.3 lb
a.i./acre. Turf has the same single application of 4.3 lb a.i./acre as ornamental grasses.
Chronic effects to terrestrial mammals are used to establish a boundary around a
treatment site beyond which potential effects to terrestrial species from captan use are not
expected. This taxa is chosen because it has the highest RQ/LOC ratio. In order to
estimate the terrestrial distance from the site of application to where RQs are predicted to
fall below the LOC, the deposition must be estimated. The initial average deposition is
calculated by multiplying the fraction of captan applied by the application rate. The
fraction of captan applied is ratio of LOC/RQ. The ratio of the LOC (1.0) for chronic
effects to mammals to the RQ (37.48) for almonds is 0.0267.
The resulting terrestrial action area buffer based on terrestrial mammals is 1001 ft for the
maximum single application rate for almond. This buffer was applied to the
orchard/vineyard, agriculture and turf land use types. Therefore, the terrestrial portion of
the captan action area for this assessment includes all potential orchard/vineyard,
agricultural and turf use sites and all areas that are within 1001 ft of potential captan use
sites in CA.
5.1.4.3. Final action area
In order to define the final action areas relevant to uses of captan on agricultural and
orchard crops, it is necessary to combine the terrestrial and aquatic areas affected by the
federal action. The initial footprint of the agricultural and orchard land cover use areas
have been expanded to include aquatic and terrestrial non-target areas affected by run-off
(determined by downstream dilution modeling) and spray drift (determined by spray drift
modeling). It is assumed that lentic (standing water) aquatic habitats (e.g. ponds, pools,
95
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marshes) in with the terrestrial areas are also affected by the federal action. The result is a
final action area for captan uses in agricultural, orchard/ vineyard and turf areas (Figure
9).
As indicated above, agricultural, orchard, and turf uses of captan could result in
deposition of captan from the atmosphere which could reach areas outside of the defined
action areas for these uses. However, since volatilization is low for captan, atmospheric
transport and deposition are not expected to play an important role in captan transport.
5.1.4.4. Overlap between CRLF habitat and final action area
In order to confirm that uses of captan have the potential to affect CRLF through direct
applications to target areas and runoff and spray drift to non-target areas, it is necessary
to determine whether or not the final action areas for agricultural and orchard crops and
turf use of captan overlap with CRLF habitats. Spatial analysis using ArcGIS 9.1
indicates that lotic aquatic habitats within the CRLF core areas and critical habitats
potentially contain concentrations of captan sufficient to result in RQ values that exceed
LOCs. In addition, terrestrial habitats (and potentially lentic aquatic habitats) of the final
action areas for agricultural, ornamental, and turf uses of captan overlap with the core
areas, critical habitat and available occurrence data for CRLF (Figure 14). Based on this
analysis, a total of 2,442 km2 (9%) of the CRLF range overlaps with the terrestrial
portion of the captan action area for agriculture and orchard uses and 1,659 km2 (6%) of
the CRLF range overlaps for turf use alone. There are 327 sections (34%) of established
occurrence sections of the CRLF that overlap with the terrestrial portion of the captan
action area for agriculture and orchard uses. There are 232 sections (25%) of established
occurrence sections of the CRLF that overlap for turf uses. The percentage of land
overlap of the terrestrial action with the CRLF habitat and the number of occurrence
sections was determined for each recovery unit (Table 5.10). Thus, uses of captan on
agricultural and orchard crops and turf use could result in exposures of captan to CRLF in
aquatic and terrestrial habitats. Additional analysis related to the intersection of the
captan action area and CRLF habitat for each recovery unit is described in Appendix E.
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Tsihlc 5.10. Siiiiiinsirv ol'enplnn lerreslrisil
hnbiliil rsmue In recovery unit (Kl ).
.lotion :ire:i llinl overlaps with CI.UI-'
Moiisuro
Kl 1
Kl 2
Kl 3
Kl 4
Kl 5
Kl (.
Kl ^
Kl S
Tul;il
I nils = knr
Agriculture niul Orchard/ \ inevsird I sos
Established species range
area (sq km)
3654
2742
1323
3279
3650
5306
4917
3326
28,197
Overlapping area
(sq km)
39
75.7
47
137
432
616
796
298
2,442
Percent area affected
1%
3%
4%
4%
12%
12%
16%
9%
9%
Established occurrence
sections (959 total; 30
outside recovery units)
13
3
70
324
276
120
90
33
929
# Occurrence sections
effected
0
0
8
75
155
30
59
0
327
Turf I sc
Overlapping area
(sq km)
56
56
62
528
275
175
239
266
1659
Percent area affected
2%
2%
5%
16%
8%
3%
5%
8%
6%
# Occurrence sections
affected
1
0
15
86
78
14
37
1
232
97
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Captan - Action Area and CRLF Habitat
Legend
| | Occurrence Sections
| Critical Habitat
Core Areas
~ Recovery units 5:3 ^
Terrestrial Action Area overlap with habitat^
- Downstream overlap with habitat
| County Boundaries
60 120 2d Kilometers
Compiled from California County boundaries (ESRI, 2002), M a p c reated by US E rw iro nmental P rote ctio n A gen cy, Offi c e
USQA National Agriculture Statistical Service (MASS 2002) of Pesticides Programs, Environmental Fate and Effects Division.
GapAnat/sis Program Orchard/ Vine/ard Land cower (GAP) September, 2007. Projection: Albers Equal Area Conic USGS,
National Land Ctwer Database (NLCD) (MRLC, 2001) North American Datum of 1983 (NAD1983!
Figure 14. Map showing the areas of overlap between the terrestrial and aquatic action
area and the CRLF habitat
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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 captan's use within the action
area. However, if direct or indirect effect LOCs are exceeded and/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 captan. A summary of
the results of the risk estimation (i.e., "no effect" or "may affect" finding) is provided in
Table 5.11 for direct and indirect effects to the CRLF and in Table 5.12 for the PCEs of
designated critical habitat for the CRLF.
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Table 5.11. Preliminary Effects Determination Summary for Captan - Direct and Indirect Effects
to CRLF
Assessment Endpoint
Preliminary
Effeets
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
Using freshwater fish as a surrogate, non-listed acute risk
LOCs are exceeded, chronic LOCs are not exceeded (Table
5.01).
Survival, growth, and reproduction
of CRLF individuals via effects to
food supply (i.e., freshwater
invertebrates, non-vascular plants,
fish and frogs)
No effect
Acute freshwater invertebrate RQs do not exceed acute or
chronic LOCs (Tables 5.03). Aquatic non-vascular plant RQs
do not exceed acute LOCs (Tables 5.02).
May affect
Non-listed acute risk LOCs are exceeded based on the most
sensitive toxicity data for freshwater fish, using fish as a
surrogate for frogs (Table 5.01).
Survival, growth, and reproduction
of CRLF individuals via indirect
effects on habitat, cover, and/or
primary productivity (i.e., aquatic
plant community)
No effect
Aquatic non-vascular plant RQs do not exceed acute LOCs
(Tables 5.02).Aquatic vascular plant LOCs are not exceeded
for applications of captan to all uses (Table 5.04).
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
RQs were not calculated for terrestrial plants due to lack of
appropriate data. Based on open literature data identified by
ECOTOX, captan as a seed treatment did not negatively impact
germination or growth of the evaluated plant species. Mild
phytotoxic effects were observed in highbush blueberries at an
application rate of 2.5 lbs ai/acre (foliar application rates for
captan range from 2.0 to 4.5 lbs ai/acre). It is unknown where
highbush blueberries fall in the species sensitivity distribution
for dicots or for terrestrial plants in general. The results of this
test indicate that a variety of terrestrial plants that may inhabit
riparian and upland zones may be sensitive to captan exposure.
Due to the high level of uncertainty, a "may affect"
determination was made.
Terrestrial Phase
(Ju veniles and adults)
Survival, growth, and reproduction
of CRLF individuals via direct
effects on terrestrial phase adults and
juveniles
May affect
Based on the available avian acute toxicity data, which is used
as a surrogate for terrestrial-phase amphibians, no mortality
was reported at the highest test concentrations of captan.
However, predicted EECs, are greater than reported acute avian
toxicity values and upper-bound RQ values exceed avian acute
and chronic LOCs for all uses (Table 5.05).
Survival, growth, and reproduction
of CRLF individuals via effects on
prey (i.e., terrestrial invertebrates,
small terrestrial mammals and
terrestrial phase amphibians)
May affect
Acute and chronic RQs for mammals and birds exceed the
LOCs. Acute RQs for terrestrial invertebrates also exceed the
LOC for all modeled uses of captan (Tables 5.05 - 5.09).
Survival, growth, and reproduction
of CRLF individuals via indirect
effects on habitat (i.e., riparian
vegetation)
May affect
RQs were not calculated for terrestrial plants due to lack of
appropriate data. Based on open literature data identified by
ECOTOX, captan as a seed treatment did not negatively impact
germination or growth of the evaluated plant species. Mild
phytotoxic effects were observed in highbush blueberries at an
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application rate of 2.5 lbs ai/acre (foliar application rates for
captan range from 2.0 to 4.5 lbs ai/acre). It is unknown where
highbush blueberries fall in the species sensitivity distribution
for dicots or for terrestrial plants in general. The results of this
test indicate that a variety of terrestrial plants that may inhabit
riparian and upland zones may be sensitive to captan exposure.
Due to the high level of uncertainty, a "may affect"
determination was made.
Table 5.12. Preliminary Effects Determination Summary for Captan - PCEs of Designated
Critical Habitat for the CRLF
Assessment Endpoint
Preliminary
Effects
Determination
Basis For Preliminary Determination
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.
May affect
RQs were not calculated for terrestrial plants due to
lack of appropriate data. Based on open literature
data identified by ECOTOX, captan as a seed
treatment did not negatively impact germination or
growth of the evaluated plant species. Mild
phytotoxic effects were observed in highbush
blueberries at an application rate of 2.5 lbs ai/acre
(foliar application rates for captan range from 2.0 to
4.5 lbs ai/acre). It is unknown where highbush
blueberries fall in the species sensitivity distribution
for dicots or for terrestrial plants in general. The
results of this test indicate that a variety of
terrestrial plants that may inhabit riparian and
upland zones may be sensitive to captan exposure.
Due to the high level of uncertainty, a "may affect"
determination was made.
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.
May affect
Alteration of other chemical characteristics
necessary for normal growth and viability of
CRLFs and their food source.
Growth and viability
of CRLF:
May affect
Using freshwater fish as a surrogate, acute LOCs are
exceeded for all uses (Table 5.01).
Food source:
No effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).Aquatic vascular plant LOCs are
not exceeded for applications of captan to all uses
(Table 5.04).
Reduction and/or modification of aquatic-
based food sources for pre-metamorphs
(e.g., algae)
No effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).
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
May affect
RQs were not calculated for terrestrial plants due to
lack of appropriate data. Based on open literature
data identified by ECOTOX, captan as a seed
treatment did not negatively impact germination or
growth of the evaluated plant species. Mild
phytotoxic effects were observed in highbush
blueberries at an application rate of 2.5 lbs ai/acre
(foliar application rates for captan range from 2.0 to
4.5 lbs ai/acre). It is unknown where highbush
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Table 5.12. Preliminary Effects Determination Summary for Captan - PCEs of Designated
Critical Habitat for the CRLF
Assessment Endpoint
Preliminary
Effects
Determination
Basis For Preliminary Determination
blueberries fall in the species sensitivity distribution
for dicots or for terrestrial plants in general. The
results of this test indicate that a variety of
terrestrial plants that may inhabit riparian and
upland zones may be sensitive to captan exposure.
Due to the high level of uncertainty, a "may affect"
determination was made.
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
May affect
RQs were not calculated for terrestrial plants due to
lack of appropriate data. Based on open literature
data identified by ECOTOX, captan as a seed
treatment did not negatively impact germination or
growth of the evaluated plant species. Mild
phytotoxic effects were observed in highbush
blueberries at an application rate of 2.5 lbs ai/acre
(foliar application rates for captan range from 2.0 to
4.5 lbs ai/acre). It is unknown where highbush
blueberries fall in the species sensitivity distribution
for dicots or for terrestrial plants in general. The
results of this test indicate that a variety of
terrestrial plants that may inhabit riparian and
upland zones may be sensitive to captan exposure.
Due to the high level of uncertainty, a "may affect"
determination was made.
Reduction and/or modification of food
sources for terrestrial phase juveniles and
adults
May affect
Acute and chronic RQs for mammals and birds
exceed the LOCs for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
Alteration of chemical characteristics
necessary for normal growth and viability of
juvenile and adult CRLFs and their food
source.
May affect
Acute and chronic RQs for mammals and birds
exceed the LOCs for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
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"
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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.
• Likelihood of the Effect Occurring: Discountable effects are those that are
extremely unlikely to occur. For example, use of dose-response information to
estimate the likelihood of effects can inform the evaluation of some discountable
effects.
• 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 Aquati c-Phase CRLF
The aquatic-phase considers life stages of the frog that are obligatory aquatic organisms,
including eggs, larvae, and tadpoles. 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 captan. As shown in Table 5.01, acute LOCs are
exceeded for all captan uses based on the highest modeled EECs and the most sensitive
freshwater fish data (used as a surrogate for aquatic-phase amphibians). Chronic LOCs
are not exceeded based on all captan uses.
The RQs for direct effects to the frog are based on maximum label rates. Surface water
monitoring data accessed from the California Department of Pesticide Regulation
program found no detectable levels of captan at monitoring sites in Monterey and Santa
Cruz counties, however this sampling only occurred on one day and is not sufficient from
which to draw conclusions. Captan data are not included in the available NAWQA
surface water monitoring data from California. The use of modeled EECs is assumed to
provide a conservative measure of captan exposures for aquatic-phase CRLFs.
Ecotoxicity data for freshwater fish are generally used as surrogates for aquatic-phase
amphibians when amphibian toxicity data are not available (U.S. EPA, 2004). Some
amphibian data were located in ECOTOX. Toxicity data for two species (ECOTOX
#90515,), the African clawed frog (Xenopus laevis, LC50 = 119.4 |ig/L in mineral water)
and the Spanish ribbed newt (Pleurodeles waltl, LC50 = 311.1 |ig/L in mineral water)
indicated that mortality effects for amphibians occur in concentrations similar to lethal
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endpoints for fish, which serve as a surrogate for aquatic phase amphibians. The results
of this study are based on nominal concentrations because measured concentrations were
not taken. In addition, turbidity was observed in the reconstituted water treatments;
therefore, there are uncertainties associated with the results of this study. Thus EFED
used the toxicity value from the fish data to calculate RQs.
The RQs for direct effects to the frog are based on the most sensitive freshwater fish data
(used as a surrogate for aquatic-phase amphibians). The brown trout was found to be the
most sensitive freshwater fish test species (LC50 = 26.2 |ig/L, MRID 40098001). Captan
is highly toxic to very highly toxic to freshwater fish (LC50s = 26.2 - 137 |ig/L) on an
acute basis. The toxicity of captan to several fish species is similar as shown in the fish
species sensitivity distribution below (Figure 1). Therefore, the endpoint for the brown
trout study is conservative, but is representative of the toxicity to several fish species. It
should be noted that acute LOCs are exceeded for 100% of the fish species included in
the distribution based on EECs for captan use with the highest application rate, almond
(RQs = 0.06-0.823).
Captan Fish Data Species Sensitivity Distribution
10
• Bluegill sunfish
•Fathead Minnow
•Bluegill sunfish
• Coho Salmon
•Fathead Minnow
•Yellow Perch
• Chinook Salmon
• Brown Trout
• Channel Catfish
• Rainbow Trout
• Bluegill sunfish
* Fathead Minnow
• Lake Trout
• Coho Salmon
• CutthroatTrout
• Lake Trout
• Lake Trout
•Brook Trout
Brown Trout
T
100
1000
LD50 (ppb)
Figure 15. Fish Species Sensitivity Distribution for Captan
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Due to lack of partial mortalities the probit slope could not be determined for the brown
trout toxicity study used as a surrogate for the aquatic-phase CRLF, information is
unavailable to estimate a slope for the dose response curve. Therefore, the probability of
an individual effect to aquatic-phase CRLFs was calculated based on a default
assumption of 4.5 (with lower and upper bounds of 2 and 9) (Urban and Cook, 1986).
The corresponding estimated chance of an individual acute mortality to the aquatic-phase
CRLF at an RQ level of 0.823 for almonds is 1 in 2.8 (with respective upper and lower
bounds of 1 in 2.3 to 1 in 4.5). The corresponding estimated chance of an individual acute
mortality to the aquatic-phase CRLF at an RQ level of 1.09 for almonds is 1 in 1.8 (with
respective upper and lower bounds of 1 in 9 to 1 in 6). There is a high probability of an
individual mortality occurrence; therefore, captan is likely to adversely affect aquatic-
phase CRLFs.
One incident has been reported involving fish kills in which it was highly probable that
captan was the cause. In New York in 1972, the spillage of a large spray rig filled with
thiodan and captan resulted in the death of 10,000 fish. This incident indicates that direct
application of captan to water bodies is highly toxic to fish, which is used as a surrogate
for the aquatic-phase CRLF. However, this incident was the result of use that is not in
accordance with the current label restrictions for direct applications to water bodies.
In summary, the Agency concludes a "likely to adversely affect" determination for direct
effects to the aquatic-phase CRLF, via acute affects, i.e. mortality, based on all available
lines of evidence.
5.2.1.2 Terrestrial-Phase CRLF
Based on acute avian toxicity data as a surrogate for the terrestrial-phase amphibians,
direct acute mortality is unknown for the terrestrial-phase CRLF via exposure to captan
applications. The avian acute and chronic effects data show no mortality at the highest
treatment levels of captan however the test levels are well below estimated exposure in
the field. Effects to birds, and therefore terrestrial-phase CRLF, are unknown at such
increased exposure levels.
Dose-based Risk
Definitive acute dose-based RQ values for terrestrial-phase CRLFs could not be derived
because the acute avian effects data show no mortality to the mallard duck (LD50 >2,000
mg/kg bw) and the Northern bobwhite quail duck (LD50 >2,150 mg/kg bw). Although
definitive dose-based RQs cannot be determined, upper bound RQs were estimated. The
predicted acute dose-based EECs (2655 - 4033 ppm based on use on peach) are about
four times the adjusted LD50 values for juvenile terrestrial-phase CRLFs (1038 mg/kg-
bw).
The T-HERPS model was used to better evaluate potential acute dose-based risk. T-
HERPS is a modification of T-REX which includes amphibian/reptile specific allometric
equations, weight classes appropriate for the CLRF, and prey items specific to the CLRF.
The refined dose-based RQs do not exceed the endangered species acute risk LOCs for
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all of the frog weight classes consuming insects. Acute dose-based LOCs are exceeded
for direct effects for large frogs (238 grams) consuming small herbivorous mammals
based on captan use on peaches (upper bound). At this time there is no refinement for
dietary and chronic risk to herptiles.
Dietary-based Risk
No mortality was observed at the highest test concentration the acute dietary-based
toxicity testing for the mallard duck, Japanese quail, and ring-necked pheasant (LC50
>5,000 mg/kg diet) and Northern bobwhite quail (LC50 >2,400 mg/kg bw). However, the
predicted acute dietary-based EECs (2331 - 3542 ppm) exceed the 2400 mg/kg diet test
levels for the quail. The EECs do not exceed the LC50 value for the mallard duck,
Japanese quail, and ring-necked pheasant (LC50 >5,000 mg/kg diet). Therefore, acute
dietary-based risk is uncertain for some species of birds at estimated field concentrations.
The mallard duck and bobwhite quail reproduction studies indicate that exposure at the
three test concentrations of 100, 300, and 1000 mg/kg diet did not affect reproduction
(NOAEC > 1000 mg/kg diet). The predicted dietary-based EECs (2331 - 3542 ppm) also
exceed these test levels by up to three times.
Because the upper bound acute and chronic dietary-based LOCs are exceeded for the
frogs using the upper bound estimate, there is uncertainty about the level of effects at
estimated field concentrations. Therefore, the effects determination for direct acute
effects to the terrestrial-phase CRLF via ingestion of terrestrial invertebrate food items is
"likely to adversely affect".
5.2.2 Indirect Effects (via Reductions in Prey Base)
5.2.2.1 Algae (non-vascular 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. Acute risk LOC
(RQ>1.0) were not exceeded for algae for all of the captan uses (Table 5.02). There is
uncertainty associated with the nonvascular aquatic plant RQs because they are based on
nominal concentrations from the green algae, Scenedesmus subspicatus toxicity study
(EC50 = 320 |_ig/L; ACC 252586). However, this study provides a conservative estimated
of the toxicity to algae compared to the other nonvascular aquatic plant studies. In a
Selenastrum capricornutum (green algae) toxicity study, the EC50 = 1770 |_ig/L (MRID
43869809). In an Anabaena flos-aquae (freshwater algae) toxicity study, the EC50 = 1200
|_ig/L (MRID 44806501). The effects determination is "no effect", for indirect effects to
aquatic-phase CRLFs based on a reduction in non-vascular aquatic plants as food items.
5.2.2.2 Aquatic Invertebrates
Indirect acute effects to the aquatic-phase CRLF via effects to prey (invertebrates) in
aquatic habitats are based on peak EECs in the standard pond and the lowest acute
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toxicity value for freshwater invertebrates. Acute and chronic risk LOCs were not
exceeded for all captan uses (Table 5.03). RQs are based on acute and chronic toxicity
endpoints of EC50 = 8400 |j,g/L and NOAEC = 560 |_ig/L, respectively. There are
uncertainties associated with the results of the chronic study because the test material was
reported as being unstable in the water therefore the test concentration in the exposure
solutions were not measured during the test. The endpoints are based on nominal
concentrations. However, it was determined that there is no potential for chronic risk
given that the chronic RQs were three orders of magnitude less that the LOC. The effects
determination is "no effect" for indirect effects to aquatic-phase CRLFs based on a
reduction of freshwater invertebrates as prey (via direct acute toxicity to freshwater
invertebrates) for all modeled uses.
5.2.2.3 Fish and Aquatic-phase Frogs
Fish and aquatic-phase frogs also represent prey of the adult CRLF. RQs associated with
acute and chronic direct toxicity to the CRLF (Table 5.01) are used to assess potential
indirect effects to the CRLF based on a reduction in freshwater fish and frogs as food
items. Given that acute RQs for direct toxicity to the CRLF exceed non-listed acute risk
LOCs for freshwater fish, the effects determination is "likely to adversely affect", based
on indirect effects as a reduction of fish and frogs as prey items for foliar application of
captan to food and ornamental/turf uses.
5.2.2.4 Terrestrial Invertebrates
When the terrestrial-phase CRLF reaches juvenile and adult stages, its diet is mainly
composed of terrestrial invertebrates. In order to assess the risks of foliar applications of
captan to terrestrial invertebrates, the bee is used as a surrogate. The most sensitive
terrestrial invertebrate study in the open literature was an acute toxicity test using Osmia
ligaria bees, the 72- hour results for acute contact endpoint was LD50 = 270 |ig a.i./bee
(Ladurner et. al, 2005, ECOTOX ref # 87252). The endpoints are similar in the registrant
submitted study in which captan is categorized as practically non-toxic (LD50 >215
Hg/bee and LD50 >10 |j,g/bee) to Apis millifera on an acute contact toxicity basis. The RQ
values based on the Osmia study exceed the LOCs (RQ>0.05) for both large and small
terrestrial invertebrates for all uses with RQs ranging from 0.03 - 2.07 (Table 5.07).
Due to lack of raw data, the probit slope could not be determined for the orchard bee
toxicity study, and therefore information is unavailable to estimate a slope for the dose
response curve. Therefore, the probability of an individual effect to terrestrial
invertebrates was calculated based on a default assumption of 4.5 (with lower and upper
bounds of 2 and 9) (Urban and Cook, 1986). The corresponding estimated chance of an
individual acute mortality to the terrestrial insects at an RQ level of 2.07 for ornamental
grasses is 1 in 1.08 (with respective upper and lower bounds of 1 in 1.36 to 1 in 1). There
is a high probability of an individual mortality occurrence; therefore, captan is likely to
cause direct adverse effects to terrestrial invertebrates. The effects determination for
indirect effects to terrestrial-phase CRLFs via reduction in terrestrial invertebrates as
dietary food items is "likely to adversely affect".
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Three incidents involving bee kills were reported in Hendersonville, NC in locations
where captan was used. However, the reported certainty indexes for the bee incidents
were categorized as "unlikely", because captan was not found in the bees.
5.2.2.5 Mammals
Life history data for terrestrial-phase CRLFs indicate that large adult frogs consume
terrestrial vertebrates, including mice. Captan is practically non-toxic for oral acute
toxicity to mammals (LD50= 9,000 mg/kg/diet, MRID 00054789, 1949); however, acute
dose-based, acute dietary-based and chronic dietary based RQs representing exposures of
captan to mice (small mammals) exceeded acute and chronic LOCs or all foliar
applications to crops (Table 5.07). Acute RQs range from 0.04 to 0.37. Chronic dose-
based RQs range from 32.27 - 269. Chronic dietary based RQs range from 3.72 - 31.02.
Acute LOCs were not exceeded for captan applied as a seed treatment, however chronic
LOCs were exceeded. Due to lack of raw data, the probit slope could not be determined
for the acute mammalian toxicity study, and therefore information is unavailable to
estimate a slope for the dose response curve. Therefore, the probability of an individual
effect to mammals was calculated based on a default assumption of 4.5 (with lower and
upper bounds of 2 and 9) (Urban and Cook, 1986). The corresponding estimated chance
of an individual acute mortality to the mammals at an RQ level of 0.37 for ornamental
grasses is 1 in 38.5 (with respective upper and lower bounds of 1 in 5.16 to 1 in 19,600).
There is a high probability of an individual mortality occurrence; therefore, captan is
likely to cause direct adverse effects to small mammals. The effects determination for
indirect effects to terrestrial-phase CRLFs via reduction in small mammals as dietary
food items is "likely to adversely affect".
The terrestrial action area was based on chronic effects to mammals because the RQ to
LOC ratio was the highest for this taxa (Section 5.1.4.2). The resulting terrestrial action
area buffer is 1001 ft for the maximum single application rate (almond). Therefore, the
terrestrial portion of the captan action area for this assessment includes all potential
orchard/vineyard, agricultural and turf use sites and all areas that are within 1001 ft of
potential captan use sites in CA.
The chronic mammalian RQ is based on the three-generation reproduction toxicity
endpoint (NOAEL = 250 mg a.i./kg diet) for the laboratory rat. Results of the study
showed decreases in the mean litter weights of pups and severe sexual organ atrophy in
adults and pups. Additionally, there were also signs of severe changes in liver weights in
the adult males as well as abdominal and intestinal atrophy. In females, there were signs
of stomach atrophy and esophageal atrophy. The reproductive effects are likely to reduce
the mammalian prey base of the CRLF.
5.2.2.6 Terrestrial-phase Amphibians
Terrestrial-phase adult CRLFs also consume frogs. RQ values representing direct
exposures of captan to terrestrial-phase CRLFs are used to represent exposures of captan
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to frogs in terrestrial habitats. Based on estimated exposures resulting from captan use,
acute and chronic risks to frogs are possible. Therefore, the effects determination for
indirect effects to large CRLF adults that feed on other species of frogs as prey, via
chronic exposure to captan, is "likely to adversely affect".
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 nearshore areas and lower 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 were assessed using RQs from freshwater aquatic vascular and non-vascular
plant data. RQs for non-vascular and vascular plants do not exceed LOCs for all captan
uses. The effects determination for indirect effects of captan to CRLFs via impacts to
habitat and/or primary production through direct effects to aquatic plants is "no effect".
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. Loss,
destruction, and alteration of habitat were identified as a threat to the CRLF in the
USFWS Recovery Plan (USFWS, 2002).
Captan is a non-systemic, phthalimide fungicide used to control fungal diseases of many
fruit, ornamental, and vegetable crops and is not expected to be lethal to terrestrial plants.
The mode of action of captan is inhibition of normal cell division of a broad spectrum of
microorganisms and fungi. Captan is known as a stressor to aquatic organisms and to
lesser degree mammals by limiting and ultimately inhibiting the process of oxidative
phosphorylation, which is needed for respiration in aquatic organisms as well as
terrestrial organisms and humans. However, effects are expected to be limited in plants.
Potential indirect effects to the CRLF resulting from direct effects on riparian and upland
vegetation are typically assessed using RQs from terrestrial plant seedling emergence and
vegetative vigor EC25 data as a screen. Because the Agency waived submission of
terrestrial plant toxicity studies for captan, there are no guideline terrestrial plant toxicity
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studies submitted for the exposure to captan to terrestrial vascular and non-vascular
plants (U.S. EPA, 1999).
Using studies obtained from ECOTOX, it was not possible to determine endpoints
analogous to the seedling emergence or vegetative vigor EC25 Therefore, no RQ
calculation was performed.
Based on open literature data identified by ECOTOX, captan as a seed treatment did not
negatively impact germination or growth of the evaluated plant species. Individual seed
exposure to captan was high as seeds were coated with captan by shaking seeds and
pesticide in a closed container. This exposure is likely to be higher than expected
exposure due to spray drift and runoff after application in the field. None of these papers
reported any negative effects of captan on germination or growth of seedlings. The results
of these studies were considered qualitatively in lieu of a seedling emergence study.
Based on ECOTOX data, there is the potential that terrestrial plants may be impacted by
foliar application of captan. In one study (#63909), highbush blueberries showed mild
phytotoxic effects at an application rate of 2.5 lbs ai/acre (foliar application rates for
captan range from 2.0 to 4.5 lbs ai/acre). It is unknown where highbush blueberries fall in
the species sensitivity distribution for dicots or for terrestrial plants in general. The results
of this test indicate that a variety of terrestrial plants that may inhabit riparian and upland
zones may be sensitive to captan exposure. However, calculated EECs are much less than
the exposure causing mild phytotoxic effects to blueberries in the study.
Further, captan has a history of being applied to a myriad of agricultural and non-
agricultural crops (as per the label), with only two incidents of 'possible' damage to
terrestrial plants. Both instances were misuse of captan and several other pesticides (1)
formulator of seed treatment combined incorrect pesticides and (2) grower did not rinse
tank thoroughly between pesticide applications and applied a pesticide not registered for
apples on apples (the damaged crop). As a foliar spray, captan may be routinely applied
multiple times per growing season. Labeled use has not resulted in any reported
incidents.
Multiple lines of evidence suggest that captan poses minimal risk to terrestrial plants. The
effects determination for indirect effects to terrestrial- and aquatic-phase CRLFs via
reduction in the terrestrial plant community is "may affect, not likely to adversely affect"
(NLAA) due to insignificant effects.
5.2.4 Modification to Designated Critical Habitat
5.2.4.1 Aquatic-Phase PCEs
Three of the four assessment endpoints for the aquatic-phase primary constituent
elements (PCEs) of designated critical habitat for the CRLF are related to potential
effects to aquatic and/or terrestrial plants:
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• 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.
• 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.
• Reduction and/or modification of aquatic-based food sources for pre-metamorphs
(e.g., algae).
The effects determinations for indirect effects to the CRLF via direct effects to aquatic
and terrestrial plants are used to determine whether modification to critical habitat may
occur. Based on the results of the effects determinations for aquatic plants (see Sections
5.2.2.1 and 5.2.3.1), there is no modification of critical habitat of the CRLF via captan-
related impacts to non-vascular and vascular aquatic plants as food items for tadpoles and
habitat for aquatic-phase CRLFs.
Multiple lines of evidence suggest that captan poses minimal risk to terrestrial plants. The
effects determination for indirect effects to terrestrial- and aquatic-phase CRLFs via
reduction in the terrestrial plant community is "may affect, not likely to adversely affect"
(NLAA) due to insignificant effects.
The remaining aquatic-phase PCE is "alteration of other chemical characteristics
necessary for normal growth and viability of CRLFs and their food source." Other than
impacts to algae as food items for tadpoles (discussed above), this PCE was assessed by
considering direct and indirect effects to the aquatic-phase CRLF via acute and chronic
freshwater fish and invertebrate toxicity endpoints as measures of effects. As discussed
in Section 5.2.1.1, direct acute effects to the aquatic-phase CRLF and/or freshwater fish
fish as food items are expected. However, captan-related effects to freshwater
invertebrates as food items are not likely to occur (5.2.2.3). Therefore, captan may result
in modification to critical habitat by altering chemical characteristics necessary for
normal growth and viability of aquatic-phase CRLFs and their non-plant food sources.
5.2.4.2 Terrestrial-Phase PCEs
Two of the four assessment endpoints for the terrestrial-phase PCEs of designated critical
habitat for the CRLF are related to potential effects to terrestrial plants:
• 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 drip line 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.
• Elimination and/or disturbance of dispersal habitat: Upland or riparian dispersal
habitat within designated units and between occupied locations within 0.7 mi of
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each other that allow for movement between sites including both natural and
altered sites which do not contain barriers to dispersal.
As discussed above, due to multiple lines of evidence suggest that captan poses minimal
risk to terrestrial plants (see Section 5.2.3.2). The effects determination for indirect
effects to terrestrial- and aquatic-phase CRLFs via reduction in the terrestrial plant
community is "may affect, not likely to adversely affect" (NLAA) due to insignificant
effects.
The third terrestrial-phase PCE is "reduction and/or modification of food sources for
terrestrial phase juveniles and adults." To assess the impact of captan on this PCE, acute
and chronic toxicity endpoints for terrestrial invertebrates, mammals, and terrestrial-
phase frogs are used as measures of effects. Based on the characterization of indirect
effects to terrestrial-phase CRLFs via reduction in the prey base (see Section 5.2.2.4 for
terrestrial invertebrates, Section 5.2.2.5 for mammals, and 5.2.2.6 for frogs), critical
habitat may be modified via a reduction in mammals and terrestrial-phase amphibians as
food items.
The fourth terrestrial-phase PCE is based on alteration of chemical characteristics
necessary for normal growth and viability of juvenile and adult CRLFs and their food
source. As discussed in Section 5.2.1.2, direct acute effects, via mortality, are expected
for the terrestrial-phase CRLF. Therefore, captan may result in modification of critical
habitat by altering chemical characteristics necessary for normal growth and viability of
terrestrial-phase CRLFs and their mammalian and amphibian food sources.
6. 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 insecticide resistance, timing of applications, cultural
practices, and market forces.
6.1.2 Aquatic Exposure Modeling of Captan
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
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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).
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 a
farmer's 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. Additionally, model inputs from the
environmental fate degradation studies are chosen to 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. Mobility input values are chosen to be
representative of conditions in the environment. The natural variation in soils adds to the
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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.
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 exposure predictions are
likely to overestimate exposure where healthy vegetative setbacks exist and
underestimate exposure where poorly developed, channelized, or bare setbacks exist.
In order to account for uncertainties associated with modeling, available monitoring data
were compared to PRZM/EXAMS estimates of peak EECs for the different uses. As
discussed above, data were not available from NAWQA for captan. Captan was not
found at detectable levels as reported by the California Department of Pesticide
Regulation surface water database (2000-2005). The use of the PRZM/EXAMS EECs is
assumed to represent a conservative measure of exposure.
6.1.3 Action Area
An example of an important simplifying assumption that may require future refinement is
the assumption of uniform runoff characteristics throughout a landscape. It is well
documented that runoff characteristics are highly non-uniform and anisotropic, and
become increasingly so as the area under consideration becomes larger. The assumption
made for estimating the aquatic action area (based on predicted in-stream dilution) was
that the entire landscape exhibited runoff properties identical to those commonly found in
agricultural lands in this region. However, considering the vastly different runoff
characteristics of: a) undeveloped (especially forested) areas, which exhibit the least
amount of surface runoff but the greatest amount of groundwater recharge; b)
suburban/residential areas, which are dominated by the relationship between
impermeable surfaces (roads, lots) and grassed/other areas (lawns) plus local drainage
management; c) urban areas, that are dominated by managed storm drainage and
impermeable surfaces; and d) agricultural areas dominated by Hortonian and focused
runoff (especially with row crops), a refined assessment should incorporate these
differences for modeled stream flow generation. As the zone around the immediate
(application) target area expands, there will be greater variability in the landscape; in the
context of a risk assessment, the runoff potential that is assumed for the expanding area
will be a crucial variable (since dilution at the outflow point is determined by the size of
the expanding area). Thus, it important to know at least some approximate estimate of
types of land use within that region. Runoff from forested areas ranges from 45 -
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2,700% less than from agricultural areas; in most studies, runoff was 2.5 to 7 times higher
in agricultural areas (e.g., Okisaka et al., 1997; Karvonen et al., 1999; McDonald et al.,
2002; Phuong and van Dam 2002). Differences in runoff potential between
urban/sub urban areas and agricultural areas are generally less than between agricultural
and forested areas. In terms of likely runoff potential (other variables - such as
topography and rainfall - being equal), the relationship is generally as follows (going
from lowest to highest runoff potential):
Three-tiered forest < agroforestry < suburban < row-crop agriculture < urban.
There are, however, other uncertainties that should serve to counteract the effects of the
aforementioned issue. For example, the dilution model considers that 100% of the
agricultural area has the chemical applied, which is almost certainly a gross over-
estimation. Thus, there will be assumed chemical contributions from agricultural areas
that will actually be contributing only runoff water (dilutant); so some contributions to
total contaminant load will really serve to lessen rather than increase aquatic
concentrations. In light of these (and other) confounding factors, Agency believes that
this model gives us the best available estimates under current circumstances.
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 cancelled.
The CPDR PUR data does not include home owner applied pesticides; therefore,
residential uses are not likely to be reported. As with all pesticide use 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 Captan
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
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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 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 this terrestrial 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.
6.2 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.
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6.2.2 Use of surrogate species effects data
Currently, there are no FIFRA guideline toxicity tests for amphibians. Therefore, in
accordance with the Overview Document (U.S. EPA 2004), data for the most sensitive
freshwater fish are used as a surrogate for aquatic-phase amphibians such as the
California red-legged frog. Available open literature information on captan toxicity to
aquatic-phase amphibians (larvae of Xenopus laevis, African clawed frog, and
Pleurodeles waltl, Spanish ribbed newt; ECOTOX# 90515) shows these non-native
species are approximately 4 to 6 times less sensitive than the freshwater fish endpoint
EFED used in the assessment. Therefore, the endpoint based on freshwater fish
ecotoxicity data is assumed to be protective. Extrapolation of the risk conclusions from
the most sensitive tested species to the California red-legged frog is more likely to
overestimate the potential risks than to underestimate the potential risk. Information to
indicate were the California red-legged frog may fall in a species sensitivity distribution
was not located.
6.2.3 Sublethal Effects
For an acute risk assessment, 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.
Open literature is useful in identifying sublethal effects associated with exposure to
captan. These effects in freshwater fish include, but are not limited to, decreased
response from olfactory epithelium and effects on endocrine-mediated processes.
However, no data are available to link the sublethal measurement endpoints to direct
mortality or diminished reproduction, growth and survival that are used by OPP as
assessment endpoints. While the study by Moore and Lower (2001) attempted to relate
the results of olfactory perfusion assays to decreased predator avoidance and homing
response in salmon, there a number of uncertainties associated with the study that limit its
utility. OPP acknowledges that sublethal effects have been associated with captan
exposure; however, at this point there are insufficient data to definitively link the
measurement endpoints to assessment endpoints. To the extent to which sublethal effects
are not considered in this assessment, the potential direct and indirect effects of captan on
CRLF may be underestimated.
7. Risk Conclusions
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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 captan to the CRLF and its designated
critical habitat. The best available data suggest that captan may affect and is likely to
adversely affect the CRLF, based on direct acute effects to aquatic-phase CRLF and acute
and chronic terrestrial-phase CRLF. In addition, captan may affect and is likely to
adversely affect the CRLF, based on indirect effects to both aquatic- and terrestrial phase
CRLFs (via reduction in terrestrial invertebrates, mammals, fish and frogs as food). In
addition, these effects also constitute modification to critical habitat via alteration of
chemical characteristics necessary for normal growth and viability of juvenile and adult
CRLFs and their food source. These effects are anticipated to occur only for those
occupied core habitat areas, CNDBB occurrence sections, and designated critical habitat
for the CRLF that are located <1001 feet from legal use sites where captan is applied
aerially.
A summary of the risk conclusions and effects determinations for the CRLF and its
critical habitat, given the uncertainties discussed in Section 6, is presented in Tables 7.1
and 7.2.
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Table 7.0 1. Effects Determination Summary
'or Captan - Direct and Indirect Effects to CRLF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
Aquatic Phase
(eggs, larvae, tadpoles, juveniles, and adults)
Direct Effects
Survival, growth, and reproduction
of CRLF individuals
LAA
Using freshwater fish as a surrogate, non-listed acute risk
LOCs are exceeded, chronic LOCs are not exceeded (Table
5.01).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects to
food supply (i.e., freshwater
invertebrates, non-vascular plants,
fish and frogs)
Aquatic
invertebrates
and non-
vascular plants:
No Effect
Acute freshwater invertebrate RQs do not exceed acute or
chronic LOCs (Tables 5.03). Aquatic non-vascular plant RQs
do not exceed acute LOCs (Tables 5.02).
Fish and Frogs:
LAA
Non-listed acute risk LOCs are exceeded based on the most
sensitive toxicity data for freshwater fish (Table 5.01).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
habitat, cover, and/or primary
productivity (i.e., aquatic plant
community)
No Effect
Aquatic non-vascular plant (Table 5.02) and vascular plant
(Table 5.04) RQs do not exceed acute LOCs for all captan uses.
Indirect Effects
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.
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses minimal
risk to terrestrial plants. Based on open literature data identified
by ECOTOX, captan as a seed treatment did not negatively
impact germination or growth of the evaluated plant species.
Mild phytotoxic effects were observed in highbush blueberries
at an application rate of 2.5 lbs ai/acre; this application rate is
much greater than the off-field EECs based on TERRPLANT
calculations.
Terrestrial Phase
(Ju veniles and adults)
Direct Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
terrestrial phase adults and juveniles
LAA
Although no mortality was observed at the highest test
concentrations in the available avian acute toxicity data, which
is used as a surrogate for terrestrial-phase amphibians,
predicted EECs are greater than highest test concentrations.
Toxicity is unknown at these exposure levels and upper-bound
RQ values exceed avian non-listed acute risk and chronic
LOCs for all uses (Table 5.05).
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
prey (i.e., terrestrial invertebrates,
small terrestrial mammals and
terrestrial phase amphibians)
LAA
Non-listed acute risk and chronic LOCs are exceeded for
mammals and birds. Acute RQs for terrestrial invertebrates also
exceed the LOC for all modeled uses of captan (Tables 5.05,
5.06, and 5.07). Non-listed acute risk LOCs are exceeded
based on the most sensitive toxicity data for freshwater fish
(Table 5.01) which are a surrogate for terrestrial phase
amphibians.
Indirect Effects
Survival, growth, and reproduction
of CRLF individuals via effects on
habitat (i.e., riparian vegetation)
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses minimal
risk to terrestrial plants. Based on open literature data identified
by ECOTOX, captan as a seed treatment did not negatively
impact germination or growth of the evaluated plant species.
Mild phytotoxic effects were observed in highbush blueberries
at an application rate of 2.5 lbs ai/acre; this application rate is
much greater than the off-field EECs based on TERRPLANT
calculations.
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Table 7.02. Effects Determination Summary for Captan - PCEs of Designated Critical Habitat
for the CRLF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
Aquatic Phase PCEs
(Aquatic Breeding Habitat and Aquatic Non-Breeding Habitat)
Indirect Effects
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.
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses
minimal risk to terrestrial plants. Based on open
literature data identified by ECOTOX, captan as a
seed treatment did not negatively impact
germination or growth of the evaluated plant
species. Mild phytotoxic effects were observed in
highbush blueberries at an application rate of 2.5
lbs ai/acre; this application rate is much greater than
the off-field EECs based on TERRPLANT
calculations.
Indirect Effects
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.
NLAA
(insignificant)
Indirect Effects
Alteration of other chemical characteristics
necessary for normal growth and viability of
CRLFs and their food source.
Growth and viability
of CRLF:
Modification
Using freshwater fish as a surrogate, non-listed acute
risk LOCs are exceeded for all uses (Table 5.01).
Food source:
No Effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).Aquatic vascular plant LOCs are
not exceeded for applications of captan to all uses
(Table 5.04).
Indirect Effects
Reduction and/or modification of aquatic-
based food sources for pre-metamorphs
(e.g., algae)
No Effect
Aquatic non-vascular plant RQs do not exceed acute
LOCs (Tables 5.02).
Terrestrial Phase PCEs
(Upland Habitat and Dispersal Habitat)
Indirect Effects
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
NLAA
(insignificant)
Multiple lines of evidence suggest that captan poses
minimal risk to terrestrial plants. Based on open
literature data identified by ECOTOX, captan as a
seed treatment did not negatively impact
germination or growth of the evaluated plant
species. Mild phytotoxic effects were observed in
highbush blueberries at an application rate of 2.5
lbs ai/acre; this application rate is much greater than
the off-field EECs based on TERRPLANT
calculations.
Indirect Effects
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
NLAA
(insignificant)
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Table 7.02. Effects Determination Summary for Captan - PCEs of Designated Critical Habitat
for the CRLF
Assessment Endpoint
Effects
Determination
Basis For Preliminary Determination
Indirect Effects
Reduction and/or modification of food
sources for terrestrial phase juveniles and
adults
Modification
Non-listed acute and chronic LOCs are exceeded for
mammals and birds for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
Indirect Effects
Alteration of chemical characteristics
necessary for normal growth and viability of
juvenile and adult CRLFs and their food
source.
Modification
Non-listed acute and chronic LOCs are exceeded for
mammals and birds for all modeled uses of captan.
Acute RQs for terrestrial invertebrates also exceed
the LOC for all modeled uses of captan (Tables 5.05
-5.09).
When evaluating the significance of this risk assessment's direct/indirect and adverse
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
121
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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.
8. References
Altig, R. and R.W. McDiarmid. 1999. Body Plan: Development and Morphology. In
R.W. McDiarmid and R. Altig (Eds.), Tadpoles: The Biology of Anuran
Larvae.University of Chicago Press, Chicago, pp. 24-51.
Alvarez, J. 2000. Letter to the U.S. Fish and Wildlife Service providing comments on
the Draft California Red-legged Frog Recovery Plan.
Bosch, Jordi and William Kemp. 2001. How to manage the blue orchard bee as an
orchard pollinator. Sustainable Agriculture Network handbook series; bk. 5).
Burns, L.A. 1997. Exposure Analysis Modeling System (EXAMSII) Users Guide for
Version 2.97.5, Environmental Research Laboratory, Office of Research and
Development, U.S. Environmental Protection Agency, Athens, GA.
Captan LUIS report. February 9, 2007. Rafael Preito (sent by email). Biological and
Economic Analysis Division. EPA.
Carsel, R.F. , J.C. Imhoff, P.R. Hummel, J.M. Cheplick and J.S. Donigian, Jr. 1997.
PRZM-3, A Model for Predicting Pesticide and Nitrogen Fate in Crop Root and
Unsaturated Soil Zones: Users Manual for Release 3.0; Environmental Research
Laboratory, Office of Research and Development, U.S. Environmental Protection
Agency, Athens, GA.
Cremlyn, 1996. Agrochemicals: Mode of Actions of Pesticides. New York Freedom
Press, New York.
Davis, M. A. and Bockus, W. W. (2001). Evidence for a Pythium sp. as a Chronic Yield
Reducer in a Continuous Grain Sorghum Field. Plant Dis. 85: 780-784. Ecotox
90836.
Fahim, M. M., Osman, A. R., Sahab, A. F., and El-Kader, M. M. A. (1983). Agricultural
Practices and Fungicide Treatments for the Control of Fusarium Wilt of Lupine.
Egypt.J.Phytopathol. 15: 35-46. Ecotox 91007
Fellers, G. M., et al. 2001. Overwintering tadpoles in the California red-legged frog
{Rana aurora draytonii). Herpetological Review, 32(3): 156-157.
Fellers, G.M, L.L. McConnell, D. Pratt, S. Datta. 2004. Pesticides in Mountain Yellow-
Legged Frogs (Rana Mucosa) from the Sierra Nevada Mountains of California,
USA. Environmental Toxicology & Chemistry 23 (9):2170-2177.
122
-------
Fellers, Gary M. 2005a. Rana draytonii Baird and Girard 1852. California Red-legged
Frog. Pages 552-554. hr. M. Lannoo (ed.) Amphibian Declines: The Conservation
Status of United States Species, Vol. 2: Species Accounts. University of
California Press, Berkeley, California, xxi+1094 pp.
(http://www.werc.usgs.gov/pt-reves/pdfs/Rana%20dravtonii.PDF)
Fellers, Gary M. 2005b. California red-legged frog, Rana draytonii Baird and Girard.
Pages 198-201. hr. L.L.C. Jones, et al (eds.) Amphibians of the Pacific Northwest.
xxi+227.
Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation
of the EPA food-chain (Kenaga) nomogram, and instrument for estimating
pesticide residues on plants. Environmental Toxicology and Chemistry 13
(9): 1383-1391.
Hayes, M.P. and M.M. Miyamoto. 1984. Biochemical, behavioral and body size
differences between Rana aurora aurora and R. a. draytonii. Copeia 1984(4):
1018-22.
Hayes and Tennant. 1985. Diet and feeding behavior of the California red-legged frog.
The Southwestern Naturalist 30(4): 601-605.
Hill, E.F., Heath, R.G., Spann, J.W., and Williams J.D. 1975. Lethal Dietary Toxicities
of Environmental Pollutants to Birds. U.S. Fish and Wildlife Service, Special
Scientific Report-Wildlife 191:1-61. (MRID# 000229-23).
Hoerger, F., and E.E. Kenaga. 1972. Pesticide residues on plants: Correlation of
representative data as a basis for estimation of their magnitude in the
environment. In F. Coulston and F. Korte, eds., Environmental Quality and
Safety: Chemistry, Toxicology, and Technology, Georg ThiemePubl, Stuttgart,
West Germany, pp. 9-28.
Jennings, M.R. and M.P. Hayes. 1985. Pre-1900 overharvest of California red-legged
frogs (Rana aurora draytonii): The inducement for bullfrog (Rana catesbeiana)
introduction. Herpetological Review 31(1): 94-103.
Jennings, M.R. and M.P. Hayes. 1994. Amphibian and reptile species of special concern
in California. Report prepared for the California Department of Fish and Game,
Inland Fisheries Division, Rancho Cordova, California. 255 pp.
Johnson, W.W., and M.T. Finley. 1980. Handbook of Acute Toxicity of Chemicals to
Fish and Aquatic Invertebrates. USFWS Publication No. 137. EPA MRID
40094602.
123
-------
Karvonen, T., Koivusalo, H., Jauhiainen, M., Palko, J. and Weppling, K. 1999. A
hydrological model for predicting runoff from different land use areas, Journal of
Hydrology, 217(3-4): 253-265.
Kupferberg, S. 1997. Facilitation of periphyton production by tadpole grazing:
Functional differences between species. Freshwater Biology 37:427-439.
Kupferberg, S.J., J.C. Marks and M.E. Power. 1994. Effects of variation in natural
algal and detrital diets on larval anuran (Hyla regilla) life-history traits. Copeia
1994:446-457.
LeNoir, J.S., L.L. McConnell, G.M. Fellers, T.M. Cahill, J.N. Seiber. 1999.
Summertime Transport of Current-use pesticides from California's Central Valley
to the Sierra Nevada Mountain Range, USA. Environmental Toxicology &
Chemistry 18(12): 2715-2722.
Mantecon, J. D. (1989). Persistence of Systemic and Non-Systemic Fungicides in the
Control of Seedling Blight of Wheat (Fusarium graminearum). Tests
Agrochem.Cultiv. 10: 76-77. Ecotox 91168
McConnell, L.L., J.S. LeNoir, S. Datta, J.N. Seiber. 1998. Wet deposition of current-use
pesticides in the Sierra Nevada mountain range, California, USA. Environmental
Toxicology & Chemistry 17(10): 1908-1916.
McDonald M.A.I; Healey J.R.; Stevens P. A. 2002. The effects of secondary forest
clearance and subsequent land-use on erosion losses and soil properties in the
Blue Mountains of Jamaica. Agriculture, Ecosystems & Environment, Volume
92, Number 1: 1-19.
McLaren, N. W. and Rijkenberg, F. H. J. (1989). Efficacy of Fungicide Seed Dressings
in the Control of Pre- and Post-Emergence Damping-Off and Seedling Blight of
Sorghum. S.Afr.J.Plant Soil 6 : 167-170. Ecotox 91004
Moore, A. and Lower, N. 2001. The Impact of Two Pesticides on Olfactory-Mediated
Endocrine Function in Mature Male Atlantic Salmon (Salmo salar L.) Parr.
Comp.Biochem.Physiol.B 129: 269-276. EcoReference No.: 67727.
Mouchet, F., Gauthier, L., Mailhes, C., Ferrier, V, and Devaux, A. 2006. Comparative
evaluation of genotoxicity of captan in amphibian larvae (Xenopus laevis and
Pleurodeles waltl) using the comet assay and the micronucleus test.
Environmental Toxicology 21(3): 264-277. Ecotox #90515
Okisaka S.; Murakami A.; Mizukawa A.; Ito J.; Vakulenko S.A.; Molotkov I.A.; Corbett
C.W.; Wahl M.; Porter D.E.; Edwards D.; Moise C. 1997. Nonpoint source runoff
modeling: A comparison of a forested watershed and an urban watershed on the
124
-------
South Carolina coast. Journal of Experimental Marine Biology and Ecology,
Volume 213, Number 1: 133-149.
Phuong V.T. and van Dam J. Linkages between forests and water: A review of research
evidence in Vietnam. In. Forests, Water and Livelihoods European Tropical
Forest Research Network. ETFRN NEWS (3pp).
Polavarapu, S. (2000). Evaluation of Phytotoxicity of Diazinon and Captan Formulations
on Highbush Blueberries. Horttechnology 10: 308-314. Ecotox 63909
Rathburn, G.B. 1998. Rana aurora draytonii egg predation. Herpetological Review,
29(3): 165.
Reis, D.K.I999. Habitat characteristics of California red-legged frogs (Rana aurora
draytonii):
Ecological differences between eggs, tadpoles, and adults in a coastal brackish
and freshwater system. M.S. Thesis. San Jose State University. 58 pp.
Seale, D.B. andN. Beckvar. 1980. The comparative ability of anuran larvae (genera:
Hyla, Bufo and Rana) to ingest suspended blue-green algae. Copeia 1980:495-
503.
Sparling, D.W., G.M. Fellers, L.L. McConnell. 2001. Pesticides and amphibian
population declines in California, USA. Environmental Toxicology & Chemistry
20(7): 1591-1595.
Teske, Milton E., and Thomas B. Curbishley. 2003. AgDisp ver 8.07 Users Manual.
USD A Forest Service, Morgantown, WV.
Urban, D.J. and Cook, N. 1986. Hazard Evaluation Division, Standard Evaluation
Procedure: Ecological Risk Assessment 104.pp. Document Number No. PB 86
247 657. EPA-540/9-86-167.
U.S. Environmental Protection Agency (U.S. EPA). 1998. Guidance for Ecological Risk
Assessment. Risk Assessment Forum. EPA/630/R-95/002F, April 1998.
U.S. EPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of
Pesticide Programs. Office of Prevention, Pesticides, and Toxic Substances.
Office of Pesticide Programs. Washington, D.C. January 23, 2004.
U.S. EPA. 1999. Reregi strati on Eligibility Decision (RED) for Captan. Office of
Pesticide Programs. September 1999.
U.S. Fish and Wildlife Service (USFWS). 1996. Endangered and threatened wildlife and
plants: determination of threatened status for the California red-legged frog.
Federal Register 61(101):25813-25833.
125
-------
USFWS. 2002. Recovery Plan for the California Red-legged Frog (Rana aurora
draytonii). Region 1, USFWS, Portland, Oregon.
(http://ecos.fws.gov/doc/recovery plans/2002/020528.pdf)
USFWS. 2006. Endangered and threatened wildlife and plants: determination of critical
habitat for the California red-legged frog. 71 FR 19244-19346.
USFWS. Website accessed: 30 December 2006.
http://www.fws.gov/endangered/features/rl frog/rlfrog.html#where
U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service
(NMFS). 1998. Endangered Species Consultation Handbook: Procedures for
Conducting Consultation and Conference Activities Under Section 7 of the
Endangered Species Act. Final Draft. March 1998.
USFWS/NMFS. 2004. 50 CFR Part 402. Joint Counterpart Endangered Species Act
Section 7 Consultation Regulations; Final Rule. FR 47732-47762.
Wassersug, R. 1984. Why tadpoles love fast food. Natural History 4/84.
Wilen, C. A., H. Costa, K. Robb, L. Greenberg, J. Kabashima and M. Parrella. 2002. Crop
Profile for the California Containerized Nursery Industry.
Willis, G.H. and L.L. McDowell. 1987. Pesticide Persistence on Foilage in Reviews of
Environmental Contamination and Toxicology. 100:23-73.
126
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