Risks of Iprodione 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 16, 2009
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Primary Authors:
Thomas Steeger, Ph.D., Senior Biologist
Kristina Garber, Biologist
Secondary Reviewers:
R. David Jones, Senior Agronomist
Anita Pease, Senior Biologist
Branch Chief, Environmental Risk Assessment Branch 4:
Elizabeth Behl
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Table of Contents
1.0 Executive Summary 9
2.0 Problem Formulation 19
2.1 Purpose 19
2.2 Scope 20
2.3 Previous Assessments 22
2.4 Stressor Source and Distribution 23
2.4.1 Environmental Fate Assessment 23
2.4.2 Mechanism of Action 31
2.4.3 Use Characterization 31
2.5 Assessed Species 38
2.5.1 Distribution 39
2.5.2 Reproduction 41
2.5.3 Diet 41
2.5.4 Habitat 42
2.6 Designated Critical Habitat 43
2.7 Action Area 45
2.8 Assessment Endpoints and Measures of Ecological Effect 48
2.8.1 Assessment Endpoints for the CRLF 48
2.8.2 Assessment Endpoints for Designated Critical Habitat 50
2.9 Conceptual Model 51
2.9.1 Risk Hypotheses 51
2.9.2 Diagram 52
2.10 Analysis Plan 54
2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model 55
3.0 Exposure Assessment 59
3.1 Surface Water Exposure Assessment 59
3.1.1 Modeling Approach 59
3.1.2 PRZM scenarios 60
3.1.3 Chemical Specific Model Inputs for Iprodione Residues of Concern 61
3.1.4 Use-Specific Model Inputs for Iprodione Residues of Concern 62
3.1.5 Modeling Results 67
3.1.6 Surface Water Monitoring Data 68
3.2 Ground Water Exposure Assessment 68
3.2.1 Modeling Approach 68
3.2.2 Modeling Results 69
3.2.3 Ground Water Monitoring Data 69
3.3 Terrestrial Animal Exposure Assessment 70
3.4 Spray Drift Modeling 74
4.0 Effects Assessment 74
4.1 Evaluation of Aquatic Ecotoxicity Studies 76
4.1.1 Toxicity to Freshwater Fish 77
4.1.2 Toxicity to Freshwater Invertebrates 79
4.1.3 Toxicity to Aquatic Plants 80
4.2 Toxicity of Iprodione to Terrestrial Organisms 81
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4.2.1 Toxicity to Birds 83
4.2.2 Toxicity to Mammals 84
4.2.3 Toxicity to Terrestrial Invertebrates 86
4.2.4 Toxicity to Terrestrial Plants 88
4.3 Toxicity of the 3,5-DCADegradate 90
4.4 Endocrine Disruption 91
4.5 Incident Database Review 92
4.5.1 Terrestrial Animal Incidents 92
4.5.2 Plant Incidents 92
4.5.3 Aquatic Animal Incidents 93
5.0 Risk Characterization 93
5.1 Risk Estimation 93
5.1.1 Exposures in the Aquatic Habitat 94
5.1.2 Exposures in the Terrestrial Habitat 101
5.1.3 Primary Constituent Elements of Designated Critical Habitat 106
5.2 Risk Description 108
5.2.1 Direct Effects 112
5.2.2 Indirect Effects (via Reductions in Prey Base) 126
5.2.3 Indirect Effects (via Habitat Effects) 132
5.2.4 Modification to Designated Critical Habitat 133
5.2.5 Addressing the Risk Hypotheses 135
6.0 Uncertainties 135
6.1 Exposure Assessment Uncertainties 135
6.1.1 Environmental Fate Data 135
6.1.2 Maximum Use Scenario 135
6.1.3 Aquatic Exposure Modeling of Iprodione 136
6.1.4 Potential Ground water Contributions to Surface Water Chemical Concentrations 137
6.1.5 Usage Uncertainties 138
6.1.6 Terrestrial Exposure Modeling of Iprodione 138
6.1.7 Spray Drift Modeling 139
6.2 Effects Assessment Uncertainties 140
6.2.1 Age Class and Sensitivity of Effects Thresholds 140
6.2.2 Use of Surrogate Species Effects Data 140
6.2.3 Sublethal Effects 140
6.2.4 Location of Wildlife Species 141
7.0 Risk Conclusions 141
8.0 References 147
Appendices
Appendix A. Nationally registered formulated products and special local needs registrations that are included in
defining the federal action for iprodione
Appendix B. Use verification memo from the Special Review and Reregistration Division.
Appendix C. Spatial characterization of overlap of initial footprint of iprodione use in CA and CRLF habitat
Appendix D. The Risk Quotient Method and Levels of Concern
Appendix E. Example PRZM/EXAMS input/output file for iprodione total residues of concern
Appendix F. Example output from T-REX v. 1.4.1
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Appendix G. List of citations accepted and rejected by ECOTOX criteria
Appendix H. Detailed spreadsheet of available ECOTOX open literature for iprodione
Appendix I. Summary of human health effects data for iprodione
Appendix J. Summary of available ecotoxicity information for iprodione TGAI and formulated products
Appendix K. Summary of reported ecological effects incidents relevant to iprodione
Appendix L. Example output from T-HERPS vl.O
Attachments
Attachment 1: Status and Life History of California Red-legged Frog
Attachment 2: Baseline Status and Cumulative Effects for the California Red-legged Frog
Figures
Figure 1. Chemical Structure of Iprodione 23
Figure 2. Average Annual Iprodione Use in continental US in Total Pounds per County in 2002.
35
Figure 3. Total annual use of iprodione in California between 1996 - 2007. California
Department of Pesticide Regulation (2007) 36
Figure 4. Recovery Unit, Core Area, Critical Habitat, and Occurrence Designations for CRLF. 40
Figure 5. CRLF Reproductive Events by Month 41
Figure 6. Initial area of concern, or "footprint" of potential use, for iprodione 47
Figure 7. Conceptual Model for Iprodione Effects on Terrestrial Phase of the CRLF 53
Figure 8. Conceptual Model for Iprodione Effects on Aquatic Phase of the CRLF 54
Tables
Table 1. Effects Determination Summary for Iprodione Use and the CRLF 13
Table 2. Effects Determination Summary for Iprodione Use and CRLF Critical Habitat Impact
Analysis 15
Table 3. LOG exceedances by direct effects RQs for the CRLF exposed to iprodione residues of
concern through iprodione applications via ground spray, soil in-furrow, chemigation
or aerial methods 16
Table 4. LOG exceedances by indirect effects RQs for prey (of the CRLF) exposed to iprodione
residues of concern through iprodione applications via ground spray, soil in-furrow,
chemigation or aerial methods 17
Table 5. Physical and chemical properties of iprodione and 3,5-DCA 23
Table 6. Environmental fate data relevant to iprodione 24
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Table 7. Iprodione degradates observed in environmental fate studies 25
Table 8. Sorption Parameters for Iprodione 29
Table 9. Batch Sorption Results for 3,5-DCA 29
Table 10. Agricultural uses of iprodione that are relevant to CA 33
Table 11. Seed treatments of iprodione that are relevant to CA 34
Table 12. Non-agricultural uses of iprodione that are relevant to CA 34
Table 13. Average annual Ibs of iprodione applied per county in CA, based on California
Department of Pesticide Registration (CDPR) Pesticide Use Reporting (PUR) Data
from 1999 to 2006. This table includes counties with an average >1000 Ibs iprodione
applied per year 37
Table 14. Average annual Ibs of iprodione applied per use in CA, based on California
Department of Pesticide Registration (CDPR) Pesticide Use Reporting (PUR) Data
from 1999 to 2006. This table includes uses with an average >1000 Ibs iprodione
applied in CA per year 38
Table 15. Iprodione uses and their respective GIS land covers used to depict the potential
"footprint" of iprodione use patterns considered for this assessment 46
Table 16. Assessment Endpoints and Measures of Ecological Effects 49
Table 17. Summary of Assessment Endpoints and Measures of Ecological Effect for Primary
Constituent Elements of Designated Critical Habitat 51
Table 18. PRZM scenario assignments according to uses of iprodione 60
Table 19. PRZM/EXAMS input parameters relevant to the fate of iprodione residues of concern.
62
Table 20. PRZM/EXAMS input parameters relevant to the use of iprodione 64
Table 21. Aquatic EECs (ug/L) for Iprodione Uses in California 67
Table 22. Input parameters for Scigrow v.2.3 used to represent iprodione residues of concern.. 69
Table 23. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for
Iprodione with T-REX 71
Table 24. Upper-bound Kenega Nomogram EECs for Dietary- and Dose-based Exposures of the
CRLF and its Prey to Iprodione 72
Table 25. EECs (ppm) for Indirect Effects to the Terrestrial-Phase CRLF via Effects to
Terrestrial Invertebrate Prey Items from Iprodione 73
Table 26. Freshwater Aquatic Toxicity Profile for Iprodione 76
Table 27. Categories of Acute Toxicity for Fish and Aquatic Invertebrates 77
Table 28. Terrestrial Toxicity Profile for Iprodione 82
Table 29. Categories of Acute Toxicity for Avian and Mammalian Studies 83
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Table 30. Summary of Direct Acute and Chronic Effect RQs for the Aquatic-phase CRLF Based
on an Acute Channel Catfish 96-hr LCso of 3,100 |ig/L and a Chronic Fathead
Minnow NOAEC of 260 |ig/L. EECs represent iprodione residues of concern 95
Table 31. Summary of RQs Used to Estimate Indirect Effects to the CRLF via Effects to Non-
Vascular Aquatic Plants (diet of CRLF in tadpole life stage and habitat of aquatic-
phase CRLF) Based on an ECso of 50 |ig/L for Naviculapelliculosa. EECs represent
iprodione residues of concern 97
Table 32. Summary of Acute and Chronic RQs Used to Estimate Indirect Effects to the CRLF
via Direct Effects on Aquatic Invertebrates as Dietary Food Items (prey of CRLF
juveniles and adults in aquatic habitats) Based on an Acute 48-hr ECso and Chronic
NO AEC for Daphnia magna of 240 |ig/L And 170 |ig/L, respectively. EECs
represent iprodione residues of concern 98
Table 33. Summary of RQs Used to Estimate Indirect Effects to the CRLF via Effects to aquatic
habitat. Based on an EC50 of 50 |ig/L for Naviculapelliculosa (algae) and an ECso of
ECso >12,640 ug/L for Lemna gibba (vascular). EECs represent iprodione residues of
concern 100
Table 34. Summary of Acute Dose- and Dietary-based RQs and Chronic Dietary-based RQ
Values Used to Estimate Direct Effects to the Terrestrial-phase CRLF (non-granular
application) 102
Table 35. Summary of RQ Used to Estimate Indirect Effects to the Terrestrial-phase CRLF via
Direct Effects on Terrestrial Invertebrates as Dietary Food Items 104
Table 36. Summary of Acute and Chronic RQs Used to Estimate Indirect Effects to the
Terrestrial-phase CRLF via Direct Effects on Small Mammals as Dietary Food Items
(non-granular application) 105
Table 37. Risk Estimation Summary for Iprodione- Direct and Indirect Effects to CRLF 109
Table 38. Risk Estimation Summary for Iprodione- PCEs of Designated Critical Habitat for the
CRLF 110
Table 39. Individual effects (mortality) chance analysis for acute exposures of aquatic-phase
CRLF to iprodione residues of concern 113
Table 40. PRZM/EXAMS input parameters relevant to the fate of iprodione (only) 114
Table 41. Aquatic EECs generated using PRZM/EXAMS for iprodione (only) 115
Table 42. PRZM/EXAMS input parameters relevant to the fate of 3,5-DCA 116
Table 43. Aquatic EECs (ug/L) for 3,5-DCA based on iprodione Uses in California 117
Table 44. Revised dose-based RQs for 1.4 g CRLF consuming different food items. EECs
calculated using T-HERPS 119
Table 45. Revised dose-based RQs for 37 g CRLF consuming different food items. EECs
calculated using T-HERPS 120
Table 46. Revised dose-based RQs for 238 g CRLF consuming different food items. EECs
calculated using T-HERPS 121
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Table 47. Revised acute dietary-based RQs for CRLF consuming different food items. EECs
calculated using T-HERPS 122
Table 48. Revised chronic dietary-based RQs for CRLF consuming different food items. EECs
calculated using T-HERPS 124
Table 49. Distance from edge of field where spray drift transport from single aerial application
rate does not exceed LOCs for exposures of the CRLF to iprodione 125
Table 50. Probability of mortality to aquatic invertebrates resulting from acute exposures to
iprodione 128
Table 51. Distance from edge of field where spray drift transport from single aerial application
rate does not exceed LOCs for exposures of the small mammals (consuming sort
grass) to iprodione 131
Table 52. Effects Determination Summary for Iprodione Use and the CRLF 143
Table 53. Effects Determination Summary for Iprodione Use and CRLF Critical Habitat Impact
Analysis 145
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1.0 Executive Summary
The purpose of this assessment is to evaluate potential direct and indirect effects on the
California red-legged frog (Rana aurora draytonif) (CRLF) arising from FIFRA regulatory
actions regarding use of iprodione on agricultural and non-agricultural sites. In addition, this
assessment evaluates whether these actions can be expected to result in modification of the
species' designated critical habitat. This assessment was completed in accordance with the U.S.
Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS) Endangered
Species Consultation Handbook (USFWS/NMFS, 1998) and procedures outlined in the
Agency's Overview Document (U.S. EPA, 2004).
The CRLF was listed as a threatened species by USFWS in 1996. The species is endemic to
California and Baja California (Mexico) and inhabits both coastal and interior mountain ranges.
A total of 243 streams or drainages are believed to be currently occupied by the species, with the
greatest numbers in Monterey, San Luis Obispo, and Santa Barbara counties (USFWS, 1996) in
California.
Iprodione is a fungicide that is currently registered for use in California for 37 different
agricultural crops. Agricultural uses include almonds, stone fruits, beans, caneberries,
bushberries, canola, cole crops, carrots, cotton, crucifer, garlic, grapes, lettuce, onions, peanuts,
potatoes, radish, rutabaga, strawberries and turnip greens. Applications to agricultural uses can
be made via several different application methods, including ground spray, spray by aircraft,
chemigation, soil, in furrow treatment, dip treatment and seed treatment. The maximum single
application rate varies by the specific agricultural use and ranges 0.27-1.37 Ibs a.i./A. Iprodione
is also used as a seed treatment on several agricultural crops. It should be noted that some
formulated product labels for iprodione allow for the use of iprodione on ginseng in California;
however, based on analysis of National Agricultural Statistics Service (NASS) data, ginseng is
not grown in California and is therefore, not relevant to this assessment. In addition, iprodione is
registered for several non-agricultural uses, including conifers, turf grass (golf courses, sod farms
and commercial industrial lawns) and ornamentals. Use of iprodione in residential areas (e.g.,
turf and ornamentals) is prohibited. For turf, maximum single applications as high as 8.16 Ibs
a.i./A can be made (to golf courses). For ornamentals, a maximum single application of 22.44 Ibs
a.i./A can be made by drench. Iprodione labels indicate that applications to areas adjacent to
water bodies (including lakes, reservoirs, rivers, streams, marshes, natural ponds, commercial
fish ponds and estuaries) should only be made where a 25 foot vegetated buffer strip exists.
Laboratory and field data indicate that parent iprodione dissipates in the environment by
hydrolysis, leaching, and runoff. Iprodione is not expected to volatilize. As such, the major
routes of transport for iprodione are expected to be spray drift and runoff. Six major degradates1
of iprodione have been identified in laboratory environmental fate studies, and an additional
degradate has been identified in field studies. One of these major degradates is 3,5-
dichloroaniline (3,5-DCA), which is the ultimate degradation product of all of the major
degradates of iprodione. It should be noted that 3,5-DCA can also be formed from the active
A major degradate is one that is measured in a laboratory fate study as > 10% of the applied parent.
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ingredient vinclozolin which is also a fungicide. Vinciozolin is registered in the U.S. where its
only two remaining uses are on canola (excluded in CA) and turf.
For the purpose of this assessment, iprodione as well as 3,5-DCA are considered to be of concern
for posing risks to non-target organisms. Because all other major degradates of iprodione
contain the 3,5-DCA moiety, the other major degradates of iprodione are also considered to be of
concern. There is a great deal of uncertainty associated with this approach because: 1) there is a
limited amount of toxicity data available for 3,5-DCA, compared to that of iprodione; 2) there
are no identified toxicity data for the major degradates that are intermediaries between iprodione
and 3,5-DCA; and 3) it is unknown whether or not iprodione and its degradates share a common
mode of action.
Since CRLFs exist within aquatic and terrestrial habitats, exposure of the CRLF, its prey and its
habitats to iprodione are assessed separately. Tier-II aquatic exposure models are used to
estimate high-end exposures of iprodione in aquatic habitats resulting from runoff and spray drift
from different uses. Peak model-estimated environmental concentrations for iprodione (only) in
surface water resulting from different iprodione uses range from 1.07 to 820 |ig/L. For 3,5-
DCA, peak estimates range 2.2 to 461 |ig/L. These estimates are supplemented with analysis of
available California surface water monitoring data from U. S. Geological Survey's National
Water Quality Assessment (NAWQA) program. The maximum concentration of iprodione
reported by NAWQA for California surface waters with agricultural watersheds is 141 |ig/L.
This value is relatively consistent with model-estimated l-in-10 year peak environmental
concentrations for iprodione. No data were available for iprodione in the California Department
of Pesticide Regulation surface water database. Monitoring data for the primary degradate of
iprodione, i.e., 3,5-DCA, indicate a maximum of 0.027 |ig/L; however, environmental detections
of 3,5-DCA cannot necessarily be attributed to iprodione, since it is not the only source of 3,5-
DCA in the environment.
To estimate iprodione exposures to the terrestrial-phase CRLF, and its potential prey resulting
from uses involving iprodione applications, the T-REX model is used for foliar uses. The T-
HERPS model is used to allow for further characterization of dietary exposures of terrestrial-
phase CRLFs relative to birds. The AgDRIFT model is also used to estimate deposition of
iprodione on terrestrial and aquatic habitats from spray drift.
The effects determination 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 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
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habitat are characterized by available data for terrestrial monocots and dicots; however, these
effects cannot be quantified due to a lack of terrestrial plant toxicity data for iprodione.
Iprodione is moderately toxic to freshwater fish and highly toxic to invertebrates on an acute
exposure basis. The no observed adverse effect concentration (NOAEC) for chronic effects to
the fathead minnow is 260 |ig/L, with a lowest observed adverse affect concentration (LOAEC)
of 550 |ig/L based on reductions in larval survival. Available chronic toxicity data for aquatic
invertebrates include a NOAEC of 170 |ig/L, with a LOAEC of 330 |ig/L based on reduction in
growth, survival and number of offspring. The ECso for algae exposed to iprodione is 50 |ig/L,
based on effects to growth. For aquatic vascular plants, the ECso is >12,640 |ig/L, based on
effects to growth.
Iprodione is slightly toxic to birds on an acute oral basis and practically non-toxic on a subacute
dietary exposure basis. Iprodione is also practically non-toxic to mammals on an acute oral
exposure basis and to honey bees on an acute contact basis. The NOAEC for chronic effects to
the Northern bobwhite quail is 300 mg/kg-diet, with a LOAEC of 1000 mg/kg-diet based on
reduced number of eggs laid, decreased hatchling body weight and decreased number of
hatchlings per number of eggs set. For mammals, the NOAEL is 150 ppm (6.1 in males and 8.4
mg/kg/day in females) based on a chronic study with rats where the LOAEL is 300 ppm (12.4 in
males and 16.5 mg/kg/day in females), based on reduced spermatozoa in the epididymides and
reduced secretion of the seminal vesicles of males. The effects of iprodione on sperm and semen
production are considered effects that could potentially reduce male fertility and impact
reproductive success in mammals. According to the iprodione RED (USEPA 1998b), iprodione
is classified as a Group B2, i.e., it is considered a "likely" carcinogen, based on evidence of
tumors in both sexes of mouse [hepatocellular adenoma/carcinoma] and in the male rat [Leydig
cell].
A limited amount of toxicity data have been identified for characterizing the effects of 3,5-DCA
on non-target organisms and based on these data, 3,5-DCA is classified as moderately toxic to
aquatic organisms on an acute exposure basis. The degradate is also classified as a carcinogen
because of its structural similarity to />ara-chloroaniline, which is a known carcinogen. No
additional data have been identified to characterize the toxicity of other major degradates of
iprodione to non-target organisms.
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
iprodione 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 each
particular type of effect are below LOCs, the pesticide is determined to have "no effect" on the
CRLF. 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 iprodione use 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
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used to distinguish those actions that "may affect, but are not likely to adversely affect" (NLAA)
from those actions that are "likely to adversely affect" (LAA) the CRLF and its critical habitat.
Based on the best available information, the Agency makes a Likely to Adversely Affect
determination for the CRLF from the uses of iprodione in California. Additionally, the Agency
has determined that there is the potential for modification of CRLF designated critical habitat
from the uses of the chemical. Summaries of the risk conclusions and supporting rationales for
the effects determinations for the CRLF and its critical habitat are presented in Table 1 and
Table 2, respectively. Use-specific determinations for direct and indirect effects to the CRLF
are provided in Table 3 and in Table 4. Given the LAA determination for the CRLF and
potential modification of designated critical habitat, a description of the baseline status and
cumulative effects for the CRLF is provided in Attachment II.
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Table 1. Effects Determination Summary for Iprodione Use and the CRLF.
Assessment
Endpoint
Effects
Determination
Basis for Determination
Survival, growth,
and/or
reproduction of
CRLF
individuals
Potential for Direct Effects
Likely to
adversely affect
(LAA) for all
uses
Aquatic-phase (Eggs, Larvae, and Adults):
Acute RQs based on iprodione residues of concern for aquatic-phase CRLF are
sufficient to exceed the LOG (0.05) for all iprodione uses that are applied via
ground spray, chemigation or air spray. For uses that result in RQs that are close
to the LOG, such as almonds (RQ = 0.06), the chance of individual mortality to an
aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high uses of iprodione
on ornamentals (26 applications per year), the chance of individual mortality to an
aquatic-phase CRLF is approximately 1 in 1.
Chronic RQs for aquatic-phase CRLF are sufficient to exceed the LOG (1.0) for the
majority of iprodione uses that are applied via ground spray, chemigation or air
spray, with the exception of almonds, beans, peanuts, stone fruit and strawberries.
Acute and chronic RQs for uses that are applied via soil in-furrow treatment (i.e.,
cotton and garlic) and seed treatments do not exceed LOCs.
If RQs were developed using EECs for iprodione only and for 3,5-DCA only, for
high use on ornamentals (26 applications per year), they would be sufficient to
exceed acute and chronic LOCs for the aquatic-phase CRLF.
There is an incident report involving a fish kill associated with the use of iprodione
on golf course turf.
Terrestrial-phase (Juveniles and Adults):
Preliminary acute RQs (generated using T-REX) exceed the level of concern for all
uses of iprodione, except cotton. Refined acute, dose-based RQs (generated using
T-HERPS) for the small CRLF consuming small insects exceed the LOG for
drench applications of iprodione on ornamentals. The likelihood of individual
mortality to small CRLF exposed to iprodione from drench applications ranges 1 in
10 to 1 in 8.9xl018. Refined acute, dose-based RQs for the medium CRLF
consuming small herbivore mammals exceed the LOG for all uses of iprodione,
except cotton. The likelihood of individual mortality for the medium CRLF is as
high as 1 in 1. Refined acute, dose-based RQs for the large CRLF exceed the LOG
for iprodione use on canola, cole crops, conifers, crucifer, ornamentals, rutabagas,
turf and turnip greens. The likelihood of individual mortality for the large CRLF is
as high as 1 in 1.
Preliminary chronic (dietary-based) RQ values generated using T-REX ranged
from 1.04 to 38.6 across 19 of the 24 use categories evaluated. Revised chronic
RQs for at least one prey item generated using T-HERPS exceed the LOG (1.0) for
every use of iprodione, except almonds, cotton and strawberries. In addition, EECs
for iprodione use on ornamentals and turf are sufficient to exceed the LOAEC.
For all uses of iprodione, spray drift exposure is of concern <37 feet from the edge
of the application site.
Potential for Indirect Effects
Aquatic prey items, aquatic habitat, cover and/or primary productivity
RQs for non-vascular plants are sufficient to exceed the LOG (1.0) for all iprodione
uses that are applied via ground spray, chemigation or air spray. The RQ for soil
in-furrqw treatment of garlic _also exceeds the LOG. RQs for soil in-furrow
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Assessment
End point
Effects
Determination
Basis for Determination
treatment to cotton and all seed treatments are below the LOG.
All aquatic invertebrate RQs for uses where iprodione is applied via ground spray,
chemigation or aerial spray are sufficient to exceed acute and chronic LOCs
Acute RQs based on iprodione residues of concern for fish and aquatic-phase
amphibians are sufficient to exceed the LOG (0.05) for all iprodione uses that are
applied via ground spray, chemigation or air spray. For uses that result in RQs that
are close to the LOG, such as almonds (RQ = 0.06), the chance of individual
mortality to an aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high
uses of iprodione on ornamentals (26 applications per year), the chance of
individual mortality to an aquatic-phase CRLF is approximately 1 in 1. Chronic
RQs for fish and aquatic-phase amphibians are sufficient to exceed the LOG (1.0)
for the majority of iprodione uses that are applied via ground spray, chemigation or
air spray, with the exception of almonds, beans, peanuts, stone fruit and
strawberries. Acute and chronic RQs for uses that are applied via soil in-furrow
treatment (i.e., cotton and garlic) and seed treatments do not exceed LOCs.
Based on the above information, there is potential for indirect effects to the aquatic-
phase CRLF from use of iprodione.
Terrestrial prey items, riparian habitat
Acute risk to terrestrial invertebrates could potentially exceed the LOG for uses of
iprodione on ornamental plants and turf. Acute dose-based RQ values and chronic
RQ values exceed the acute and chronic risk LOCs for small mammals serving as
prey. Chronic RQ values exceed the chronic risk LOG for terrestrial-phase
amphibians serving as prey for terrestrial-phase CRLF. There is considerable
uncertainty regarding the effects of iprodione on terrestrial invertebrates and based
on incident data, risk is presumed.
There is uncertainty regarding the chemical's potential effect on terrestrial plants
that provide [riparian] cover for aquatic environment; therefore, risk is presumed.
Additionally, there are incident reports involving terrestrial plants where registered
uses of iprodione resulted in damage to plants.
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Table 2. Effects Determination Summary for Iprodione Use and CRLF Critical Habitat Impact Analysis.
Assessment
Endpoint
Effects
Determination
Basis for Determination
Modification
of aquatic-
phase PCE
Habitat
Modification
Modification
of terrestrial-
phase PCE
There is uncertainty (due to a lack of effects data for plants) regarding the chemical's
potential effect on terrestrial plants that provide [riparian] cover for aquatic
environment; therefore, risk is presumed. Additionally, there are incident reports
involving terrestrial plants where registered uses of iprodione resulted in damage to
plants.
RQs for non-vascular plants that may serve as a forage base for aquatic-phase CRLF
are sufficient to exceed the LOG (1.0) for all iprodione uses that are applied via ground
spray, chemigation or air spray. The RQ for soil in-furrow treatment of garlic also
exceeds the LOG. RQs for soil in-furrow treatment to cotton and all seed treatments
are below the LOG.
All aquatic invertebrate RQs for uses where iprodione is applied via ground spray,
chemigation or aerial spray are sufficient to exceed acute and chronic LOCs
Acute RQs based on iprodione residues of concern for fish and aquatic-phase
amphibians are sufficient to exceed the LOG (0.05) for all iprodione uses that are
applied via ground spray, chemigation or air spray. For uses that result in RQs that
are close to the LOG, such as almonds (RQ = 0.06), the chance of individual mortality
to an aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high uses of
iprodione on ornamentals (26 applications per year), the chance of individual mortality
to an aquatic-phase CRLF is approximately 1 in 1. Chronic RQs for fish and aquatic-
phase amphibians are sufficient to exceed the LOG (1.0) for the majority of iprodione
uses that are applied via ground spray, chemigation or air spray, with the exception of
almonds, beans, peanuts, stone fruit and strawberries. Acute and chronic RQs for uses
that are applied via soil in-furrow treatment (i.e., cotton and garlic) and seed
treatments do not exceed LOCs.
There is uncertainty regarding the chemical's potential effect on terrestrial plants that
provide cover for the terrestrial environment; therefore, risk is presumed. Additionally,
there are incident reports involving terrestrial plants where registered uses of iprodione
resulted in damage to plants.
Acute risk to terrestrial invertebrates could potentially exceed the level of concern for
uses of iprodione on ornamental plants and turf. Additionally, there is uncertainty
regarding the potential effects of iprodione on larval terrestrial invertebrates and risk is
presumed based on an incident report. Acute dose-based RQ values and chronic RQ
values exceed the acute and chronic risk LOCs for small mammals serving as prey.
Chronic RQ values exceed the chronic risk LOG for terrestrial-phase amphibians
serving as prey for terrestrial-phase CRLF.
Dietary-based chronic RQ values exceed the chronic risk LOG for terrestrial-phase
amphibians by factors as high as 28X and as such, available mammalian prey items
may be reduced in CRLF habitat.
15
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Table 3. LOG exceedances by direct effects RQs for the CRLF exposed to iprodione residues of concern
through iprodione applications via ground spray, soil in-furrow, chemigation or aerial methods.
Use(s)
Almonds
Beans
Berries1
Canola
Carrots
Cole crops2
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce
Onions
Ornamentals
Peanuts
Potatoes
Radishes
Rutabagas
Stone fruit3
Strawberries
Turf4
Turnip greens
Aquatic Habitat
Acute
YES
YES
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Chronic
no
no
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
no
YES
YES
YES
no
no
YES
YES
Terrestrial Habitat
Acute
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Chronic
no
no
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
1 specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries,
loganberries, raspberries
2 specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 specifically, apricots, cherries, nectarines, peaches, plums, prunes
4 golf course, sod farm, commercial industrial lawns
16
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Table 4. LOG exceedances by indirect effects RQs for prey (of the CRLF) exposed to iprodione residues of concern through iprodione applications via
ground spray, soil in-furrow, chemigation or aerial methods.
Use(s)
Almonds
Beans
Berries1
Canola
Carrots
Cole crops2
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce
Onions
Ornamentals
Peanuts
Potatoes
Radishes
Rutabagas
Stone fruit3
Strawberries
Turf4
Turnip greens
Algae
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Aquatic
Invertebrates
Acute
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Chronic
YES
YES
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Terrestrial
Invertebrates
(Acute)
no
no
no
no
no
no
no
no
no
no
no
no
no
YES
no
no
no
no
no
no
YES
no
Aquatic-phase frogs
and fish
Acute
YES
YES
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Chronic
no
no
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
no
YES
YES
YES
no
no
YES
YES
Terrestrial-phase
frogs
Acute
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
Chronic
no
no
YES
YES
YES
YES
YES
no
YES
no
YES
YES
YES
YES
YES
YES
YES
YES
YES
no
YES
YES
Small Mammals
Acute
no
no
no
no
no
no
YES
no
no
no
no
no
no
YES
no
no
no
no
no
no
YES
no
Chronic
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
1 Specifically: blackberries, blueberries, caneberries, currants elderberries, gooseberries, huckleberries, loganberries, raspberries
2 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
' Specifically: apricots, cherries, nectarines, peaches, plums, prunes
' golf course, sod farm, commercial industrial lawns
17
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Based on the conclusions of this assessment, a formal consultation with the U. S. Fish and
Wildlife Service under Section 7 of the Endangered Species Act should be initiated
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 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.
18
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2.0 Problem Formulation
Problem formulation provides a strategic framework for the risk assessment. By identifying the
important components of the problem, it focuses the assessment on the most relevant life history
stages, habitat components, chemical properties, exposure routes, and endpoints. The structure
of this risk assessment is based on guidance contained in U.S. EPA's Guidance for Ecological
Risk Assessment (U.S. EPA 1998), the Services' Endangered Species Consultation Handbook
(USFWS/NMFS 1998) and is consistent with procedures and methodology outlined in the
Overview Document (U.S. EPA 2004) and reviewed by the U.S. Fish and Wildlife Service and
National Marine Fisheries Service (USFWS/NMFS 2004).
2.1 Purpose
The purpose of this endangered species assessment is to evaluate potential direct and indirect
effects on individuals of the federally threatened California red-legged frog (Rana aurora
draytonii) (CRLF) arising from FIFRA regulatory actions regarding agricultural and
nonagricultural uses of iprodione (see use characterization for specific uses). In addition, this
assessment evaluates whether these uses expected to result in modification of the species'
designated critical habitat. This ecological risk assessment has been prepared consistent with a
settlement agreement in the case Center for Biological Diversity (CBD) vs. EPA et al. (Case No.
02-1580-JSW(JL)) settlement entered in Federal District Court for the Northern District of
California on October 20, 2006.
In this assessment, direct and indirect effects to the CRLF and potential modification to its
designated critical habitat are evaluated in accordance with the methods described in the
Agency's Overview Document (U.S. EPA 2004). Screening level methods include use of
standard models such as PRZM-EXAMS, T-REX, and AgDRIFT, all of which are described in
the Overview Document. Additional refinements include use of the T-HERPS model. 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 iprodione is based on an action area. The action area is the area directly or
indirectly affected by the federal action, as indicated by the exceedance of the Agency's Levels
of Concern (LOCs). It is acknowledged that the action area for a national-level FIFRA
regulatory decision associated with a use of iprodione may potentially involve numerous areas
throughout the United States and its Territories. However, for the purposes of this assessment,
attention will be focused on relevant sections of the action area including those geographic areas
associated with locations of the CRLF and its designated critical habitat within the state of
California. As part of the "effects determination," one of the following three conclusions will be
reached regarding the potential use of iprodione in accordance with current labels:
• "No effect";
• "May affect, but not likely to adversely affect"; or
19
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• "May affect and likely to adversely affect".
Designated critical habitat identifies specific areas that have the physical and biological features,
(known as primary constituent elements or PCEs) essential to the conservation of the listed
species. The PCEs for CRLFs are aquatic and upland areas where suitable breeding and non-
breeding aquatic habitat is located, interspersed with upland foraging and dispersal habitat.
If the results of initial screening-level assessment methods show no direct or indirect effects (no
LOG exceedances) upon individual CRLFs or upon the PCEs of the species' designated critical
habitat, a "no effect" determination is made for use of iprodione as it relates to this species and
its designated critical habitat. If, however, potential direct or indirect effects to individual
CRLFs are anticipated 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
iprodione.
If a determination is made that use of iprodione 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 iprodione use sites) and
further evaluation of the potential impact of iprodione on the PCEs is also used to determine
whether modification of designated critical habitat may occur. Based on the refined information,
the Agency uses the best available information to distinguish those actions that "may affect, but
are not likely to adversely affect" from those actions that "may affect and are likely to adversely
affect" the CRLF or the PCEs of its designated critical habitat. This information is presented as
part of the Risk Characterization in Section 5 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 iprodione is
expected to directly impact living organisms within the action area (defined in Section 2.7),
critical habitat analysis for iprodione 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 iprodione
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
Iprodione is a non-systemic fungicide currently registered in the United States for use on a
variety of fruits, vegetables and ornamentals. These uses are considered as part of the federal
action evaluated in this assessment.
20
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The end result of the EPA pesticide registration process (i.e., the FIFRA regulatory action) is an
approved product label. The label is a legal document that stipulates how and where a given
pesticide may be used. Product labels (also known as end-use labels) describe the formulation
type (e.g., liquid or granular), acceptable methods of application, approved use sites, and any
restrictions on how applications may be conducted. Thus, the use or potential use of iprodione in
accordance with the approved product labels for California is "the action" relevant to this
ecological risk assessment.
Although current registrations of iprodione allow for use nationwide, this ecological risk
assessment and effects determination addresses currently registered uses of iprodione 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.
Laboratory and field data indicate that parent iprodione dissipates in the environment by
hydrolysis, leaching, and transport with water. Iprodione is not expected to volatilize. As such,
the major routes of transport are expected to be spray drift and runoff. Although iprodione has
several major degradates, the compound ultimately degrades to 3,5-dichloroaniline (3,5-DCA).
This compound is classified as a carcinogen because of its structural similarity to para-
chloroaniline, which is a known carcinogen. It should be noted that 3,5-DCA can also be formed
from the fungicide vinclozolin. Vinclozolin is registered in the U.S. where its only two
remaining uses are on canola (prohibited by labels for use in CA) and turf. According to CA
PUR data, vinclozolin use in CA (102 Ibs/year) is likely to be orders of magnitude less than
iprodione (105 Ibs/year, see section 2.4.3).
For the purpose of this assessment, iprodione as well as 3,5-DCA are considered to be of concern
for posing risks to non-target organisms. Because all other major degradates of iprodione
contain the 3,5-DCA moiety, the other major degradates of iprodione are also considered to be of
concern. There is a great deal of uncertainty associated with this approach because: 1) there is a
limited amount of toxicity data available for 3,5-DCA, compared to that of iprodione; 2) there
are no identified toxicity data for the major degradates that are intermediaries between iprodione
and 3,5-DCA; and 3) it is unknown whether or not iprodione and its degradates share a common
mode of action.
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). No environmental mixture studies involving iprodione were identified in
the scientific literature using ECOTOX.
21
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Iprodione has several registered products that contain multiple active ingredients. All but one of
these products contain iprodione in combination with the fungicide thiophinate-methyl (CAS
23564-05-8). The one other product contains iprodione co-formulated with trifloxystrobin (CAS
141517-21-7). Data are available to assess the hazard associated with products co-formulated
with thiophinate-methyl but not trifloxystrobin. The available data indicate that the formulated
products have similar toxicity to that of technical grade iprodione alone.
2.3 Previous Assessments
Iprodione was registered for use on ornamentals and turf in 1981, on stone fruits in 1982, on
potatoes in 1994, and on snap beans on 1997. The 1997 assessment noted that chronic toxicity
studies were unavailable for aquatic animals; however, chronic exposure to birds and mammals
resulted in reproductive effects that were characterized as anti-androgenic and indicative of a
chemical acting on endocrine-mediated processes.
Several Section 18 emergency exemptions have been granted for the use of iprodione on
caneberries in Washington State (1985), on canola (1997) in North Dakota and Minnesota, and
on almonds in California (2007). In these assessments risk of acute mortality were identified for
freshwater invertebrates and for birds, reptiles, terrestrial-phase amphibians and mammals; risk
of chronic effects were identified for mammals.
In the 2000 reregi strati on RED, iprodione is classified as a Group C chemical (possible human
carcinogen). The terminal metabolite of iprodione, 3,5-DCA, is considered to have a genotoxic
mode of tumor induction based on its similarity to its structural analog />ara-chloraniline, which
is carcinogenic in mammals.
In 2007, an Inter-Regional 4 (IR-4) petition for the new use of iprodione on pistachios and for
revised application rates for use on strawberries, stone fruits and grapes and additional uses on
canola, pistachios and almonds were evaluated. The evaluation concluded that based on the
newly proposed uses on pistachios, almonds and canola and the revised use rates on strawberries,
stone fruits and grapes, acute risk levels of concern for endangered species were exceeded for
both terrestrial and aquatic animals.
22
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2.4 Stressor Source and Distribution
2.4.1
Environmental Fate Assessment
Iprodione is moderately mobile (per FAO classification system) in soil systems with an organic
carbon partition coefficient (Koc) of approximately 500 mL/g. It is not particularly volatile;
therefore, it should not be subject to long-range atmospheric transport. Iprodione is most
persistent in acidic environments, with approximate half lives of 131 days at a pH of 5 in aquatic
systems; however, in neutral aquatic systems, the half life drops to 4.7 days (pH of 7), and in
basic systems, iprodione quickly dissipates (27 minutes at pH of 9). For aquatic systems, there is
no strong evidence of effective mechanisms of iprodione degradation other than hydrolysis. The
physical and chemical properties of iprodione and 3,5-DCA are provided in Table 5. The
environmental fate and transport data relevant to iprodione are summarized below and in Table
6. The structure of iprodione is provided in Figure 1.
The major degradates observed in laboratory and field studies are summarized in Table 7. The
table also shows the fate studies that produced the degradates and the maximum percent of
parent at which each of the degradates appeared in the studies. The only degradate that the
Health Effects Division has reported to be of toxicological concern is 3,5-dichloroaniline (3,5-
DCA or RP-32596), and it was found in several of the laboratory studies. This assessment
includes consideration for the exposure of both iprodione and 3,5-DCA.
CH.
Figure 1. Chemical Structure of Iprodione
Table 5. Physical and chemical properties of iprodione and 3,5-DCA.
Parameter (units)
Molecular weight (g/mol)
Vapor Pressure (torr)
Henry's Law Constant (atm-m3/mol) '
Solubility in Water (mg/L; @20°C)
Octanol-water partition coefficient (Kow)
Iprodione2
330.2
2.7xlO"7
9.0xlO'9
13
1259
3,5-DCA3
162.02
2.12xlQ-2
5.8 xlO'6
784
794
1 Calculated according to USEPA 20026 by: (VP *MW)-(760*solubility).
2 From registrant-submitted product chemistry data.
3EPISuite
23
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Table 6. Environmental fate data relevant to iprodione.
Parameter (units)
Hydrolysis Half-lives (d)
pH5
pH7
pH9
Aqueous Photolysis Half-life (d)
Soil Photolysis Half -life (d)
Aerobic Soil Metabolism Half-life (d)
Anaerobic Soil Metabolism Half -life (d)
Aerobic aquatic metabolism half -life (d)
Anaerobic aquatic metabolism half -life (d)
Value(s)
131
4.7
0.019 (27 min)
67
negligible
30 to 3001
24 to 1002
Source (MRID)
41885401
41861901
42897101
43091002
44590501
Not available
3-73
7-14 3
41927601
42503801
41755801
IThe DT50 of the extracted iprodione was 14-30 days. It is difficult to estimate actual degradation rates from this
study because unextracted and uncharacterized residues accounted for >75% of the applied 14C at 181-276 days (last
test interval). The half life could be higher than 300 days if all the unidentified unextracted material were iprodione.
2The shorter half life was based on the regression of extractable iprodione only. The longer half life was based on
the observation that at 100 days there was more than 50% unrecovered and uncharacterized material that could have
been iprodione.
Degradation of iprodione was most likely driven by hydrolysis.
24
-------
Table 7. Iprodione degradates observed in environmental fate studies.
Chemical Name
Registrant Name of
degradate
Chemical Structure
Study in Which Found Reference
(Maximum % of Parent) MRID
3,5-dichloroaniline
(or 3,5-DCA)
RP32596
Soil Photolysis (28%)*
Aerobic Soil (9%)
Aerobic Soil (3. 9%)
Aerobic Aquatic (10%)
Anaerobic Aquatic (3.
42897101
43091002
44590501
42503801
41755801
3-(l-methylethyl)-N-(3,5-
dichlorophenyl)-2,4-dioxo-
1-imidazolidine-
carboxamide
RP30228
Hydrolysis (pH 7) (45.6%)
Hydrolysis (pH 9) (93%)
Soil Photolysis (7.7%)
Aerobic Soil (29%)
Aerobic Aquatic (65%)
Anaerobic Aquatic (60%)
Terrestrial Field (-)
Aquatic Field (--)
41885401
42897101
44590501
42503801
41755801
41877401
43718301
[(dichloro-3,5-phenyl)-l-
isopropy Icarbamoy 1-3 ] -2-
acetic acid
CH,— COOH
RP35606
_
{(~j) — NH— C— N— C— NH— CH(CH,},
Hydrolysis (pH 5) (12%)
Hydrolysis (pH 7) (10.1%)
41885401
3 -(3 ,5-dichlorophenyl)-
2,4-dioxoimidazolidine
RP25040
Soil Photolysis (14%)
Aerobic Soil (9.5
42897101
43091002
25
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Chemical Name
Registrant Name of
degradate
Chemical Structure
Study in Which Found Reference
(Maximum % of Parent) MRID
3 -(3,5-dichlorophenyl)-
2,4-dioxo-l-imidazolidine-
carboxamide
RP32490
CO.NH,
Aerobic Aquatic (15%) 42503 801
Terrestrial Field (-) 41877401
N-(3,5-dichlorophenyl)-2-
(l-methylethyl)-l-
ureylenecarboxamide
RP37176
<-/
NHCCCH,NHCCNHCH( CH.)
Aquatic Field (--)
43718301
l-(3,5-dichlorophenyl)-5-
isopropyl biuret
RP36221
HCCNHOONHCH(CH,)i
Aerobic Soil (13%)
44590501
*Photolysis is probably not the mechanism for production of 3,5-DCA in this study since the dark control produced nearly equivalent amounts of 3,5-DCA.
26
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Hydrolysis
The pH-dependent hydrolysis half life of iprodione is 131 days at a pH of 5, 4.7 days at a pH of
7, and 27 minutes at a pH of 9. These values were derived from laboratory studies (MRID
41885401) in sterile aqueous buffered solutions maintained at 25°C. At pH 7 (neutral water), RP
30228 and RP 35606 were observed as major degradates, with the former increasing throughout
the study to a maximum of 45.6% of total radioactivity measured at the conclusion of the study.
Iprodione, RP 30228 and RP 35606 comprised approximately 90% of the total residues
throughout the study, indicating that iprodione residues of concern are stable to hydrolysis at pH
7.
Photolysis
In an aqueous photolysis study, iprodione degraded slowly with a half life of 67 days in a pH 5
buffered solution that was irradiated continuously with a UV-filtered xenon-arc lamp (MRID
41861901). The test ran for 33 days in conditions reported to simulate Florida sunlight.
Iprodione did not degrade significantly in the dark control. No major degradates (>10% of the
applied) were observed in this study.
In a soil photolysis study, iprodione degraded at a somewhat higher rate under irradiated
conditions than in the dark control in a soil photolysis study (MRID 42897101). On irradiated
soils, iprodione degraded with an observed DT50 of 7-14 days in sandy loam soil that was
irradiated with a xenon-arc lamp for 8.8 hours/day for 30 days; whereas, in the dark controls,
iprodione degraded with an observed DT50 of 14-21 days. Registrant-calculated half lives, using
a first-order degradation model, were 4.64 days for the irradiated sample and 5.15 days for the
dark control, thus degradation by irradiation is minimal. The major degradate observed in the
irradiated soil was RP32596 [3,5-DCA] with a maximum of 28% of the applied at 14 days; while
the dark control produced 37% of 3,5-DCA. Other degradates include a mixture of RP25040 and
LS720942 with a maximum of 13.75% of the applied at day 7 (3% in the dark control), and
RP30228 with a maximum of 7.72% immediately post treatment (11% in the dark control).
Microbial degradation (metabolism)
In an aerobic soil metabolism study (MRID 43091002) conducted in a sandy loam soil that was
incubated in the dark at 25°C and 75% of 0.33 bar moisture for 276 days, unextracted and
uncharacterized residues accounted for 75.8 to 86.9% of the applied 14C at 181-276 days (last
test interval). Thus, it is difficult to estimate actual degradation rates. The half life could be
higher than 300 days if all the unidentified unextracted material were iprodione. The DTso of the
extracted iprodione was 14-30 days. The following degradates were observed: RP30228, with a
maximum of 6.92% of the applied at 14 days; RP32596 (3,5-DCA), with a maximum of 9.02%
of the applied at 30 days; and RP25040, with a maximum of 9.47% of the applied at 30 days.
Volatile residues totaled 5.27% of the applied at 276 days (of which 5.23% was CO2). Note: the
soil used was the same soil used in the soil photolysis study (i.e., MRID 42897101). In a shorter
100-day aerobic soil metabolism study (MRID 44590501), iprodione degraded with a half-life
between 23.9 and 100 days. The shorter half life was based on the regression of extractable
iprodione only. The longer half life was based on the observation that at 100 days there was
27
-------
more than 50% unrecovered and uncharacterized material that could have been iprodione.
Degradates were RP30228 (observed at a maximum of 29.5 %), RP36221 (observed at a
maximum of 12.7%), and 3,5-DCA (observed at a maximum of 3.9%).
An aerobic soil metabolism study of 3,5-DCA (on two different soils) showed little evidence that
3,5-DCA appreciably degraded over a 9-month period at 25°C (MRID 45239201). Apparent
dissipation was caused by a high level of unextracted residue. Unextracted residues accounted
for 66% and 81% of the applied in the two systems. The only residues that were distinguishable
from the parent amounted to only 4 to 5% of the applied 14C.
In an aerobic aquatic metabolism study, iprodione degraded with an observed DTso of 3-7 days
in a flooded silt loam sediment system incubated in the dark (MRID 41927601 and 42503801).
However, the pH of the system was 8.5, which is a level at which hydrolysis is a major
mechanism of degradation. In the pH range between 7 and 9, iprodione degrades with a half life
between 27 minutes and 4.7 days, as shown in a separate hydrolysis study (MRID 41885401).
Thus hydrolysis is likely the means of degradation in these studies rather than metabolism. The
major degradates were RP30228, with a maximum of 64.6% of the applied at 14 days, RP32490,
with 14.6% of the applied at 2 days, and 3,5-DCA with a maximum of 10% observed at the
conclusion of the study (day 30), indicating that the duration of the study was not necessarily of
sufficient duration to capture the full formation and decline of 3,5-DCA.
In an anaerobic aquatic metabolism study, iprodione degraded with an observed DT50 of 7-14
days in anaerobic (flooded plus nitrogen atmosphere) silt loam sediment that was incubated in
the dark at 25°C (MRID 41755801). The pH of the water was 7.4, which is a level at which
hydrolysis is likely the most significant degradation mechanism. A sterile control showed that
iprodione degrades at about the same rate under sterile conditions, but RP-30228 did not
dissipate (accounting for about 90% of applied after 1 year); whereas in the unsterilized test, it
accounted for only about 10% after 1 year. Thus degradation of the parent does not appear to be
microbially mediated, but degradation of RP-30228 does appear to be microbially mediated. The
major degradates were RP30228 with a maximum of 70.7% of the applied at 14 days post-
treatment; RP32490 with a maximum of 8.4% of the applied at 30 days. CC>2 accounted for 5.5-
6.3% of the applied at 365 days. Organic volatiles were <0.6%, and unextracted residues were
16.7-20.0% of the applied.
Volatilization
Iprodione is not particularly volatile as indicated by the approximated Henry's Law constant
(derived from vapor pressure, solubility, and molecular weight) of 2.7 x 10"9 atm-m3/mol. Thus,
long-range transport is not a concern. The Agency has not received any direct measurements of
volatility information for 3,5-DCA. In the absence of such data, the Agency used EPISuite™,
which estimated that the Henry's Law constant is much higher than for the parent (around 10"6
atm-mVmol). This value would imply that 3,5-DCA should be more volatile than the parent.
28
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Sorption
Batch sorption tests (MRID 43349202) for iprodione in four soils are summarized in Table 8.
Iprodione isotherms for these four soils are reasonably linear, with Freundlich exponents from
0.85 to 1.2. The mean of the organic carbon partitioning coefficients is 426 ml/g OC, which is
classified as moderately mobile by the FAO mobility classification scheme (USEPA, 2006). KF
values for iprodione correlated with soil organic matter content (R2 = 0.99), indicating that Koc
is a representative measure of the soil partitioning of iprodione.
Table 8. Sorption Parameters for Iprodione4.
Soil
Loam
Sandy loam
Loamy sand
Clay
Fraction of
Organic Carbon
(foe)
0.085
0.011
0.005
0.012
Freundlich
Coefficient
K/'2
43.1
2.45
2.16
6.52
Freundlich
Exponent
1/N (1)
0.908
0.905
0.858
1.204
K^Cml/gnOC) 3
507
223
431
543
1 Freundlich Isotherm S= KF(r
2 KF has units of [mg/kg] [L/mgf,
3 Koc value is based on the sorption coefficient (S/C, where S is sorbed concentration and C is aqueous concentration) that
occurs at an aqueous concentration of 1 mg/L, which has a numerical value that is equivalent to KF/foc.
4 These values were calculated by the registrant using the amount of decanted volume of water as the amount of water in
contact with the soil, as opposed to the correct way of performing this calculation which would have been to use the total
volume of water. An assessment of this error showed that the volume of water would have been underestimated by about
10% (see MRID 43349202 Table All.3). This type of error would most significantly affect the lower IQ estimates; whereas
higher Kd values would be less affected. For the cases reported in this table the sorption coefficient error should be less than
20%. One value reported by the registrant had a IQ of 0.06 and the error associated with this would be so great as to make
its value meaningless and thus this value was excluded from the analysis and this table.
Batch sorption tests (MRIDs 41888904 and 45114101) for 3,5-DCA in several soils are
summarized in Table 9. Isotherms of 3,5-DCA for these soils are nonlinear, with Freundlich
exponents of approximately 0.7. This means that the sorption affinity increases as
concentrations decrease and that 3,5-DCA will become less mobile as concentrations decrease.
According to standard EFED practice, this chemical is classifieds as moderately mobile
(USEPA, 2006), with an average Koc of 610 ml/gorganic carbon. KF values for 3.5-DCA are
correlated with soil organic matter content (R2 = 0.72), indicating that Koc is a representative
measure of the soil partitioning of 3.5-DCA.
Table 9. Batch Sorption Results for 3,5-DCA.
Soil
Sand
Sandy loam
Sandy loam
Loamy sand
Silt loam
Loam
Clay loam
Clay
Pond sediment
Fraction of
Organic
Carbon (foe)
0.00116
0.00522
0.003422
0.01189
0.026042
0.00638
0.01102
0.010962
0.006264
Freundlich
Coefficient (U)
(KF)
0.576
1.86
1.75
7.17
10.98
2.60
10.0
9.17
4.635
FreundlichExponent'1'2'
(1/N)
0.74
0.82
0.68
0.634
0.692
0.79
0.76
0.743
0.646
1C <3)
(ml/gCOC)
496
356
593
626
380
408
908
932
788
MRID
41888904
41888904
45114101
45114101
45114101
41888904
41888904
45114101
45114101
29
-------
Freundlich Isotherm S= KFC1/>;
KF has units of [mg/kg^L/mg]1
Koc value is based on the sorpti
occurs at an aqueous concentration of 1 mg/L, which has a numerical value that is equivalent to KF/foc.
2 KF has units of [mg/kg] [L/mg]1/N,
3 Koc value is based on the sorption coefficient (S/C, where S is sorbed concentration and C is aqueous concentration) that
Bioaccumulation
In a bioconcentration study with bluegill sunfish, iprodione residues concentrated in fish tissues
at a factor of 72X for whole fish. After a 14-day depuration period, total radioactive residues
declined 99% (from maximum). Several iprodione degradates were reported in fish tissue,
including RP25040, RP30228, RP32490and RP36119 (MRID 43091001). The octanol-water
partition coefficient (Log Kow = 3.10) along with the submitted BCF studies indicate that
iprodione is not likely to bioaccumulate significantly in aquatic ecosystems.
Field Dissipation Studies
Two terrestrial field dissipation studies are available (both described in MRID 41877401).
Neither study monitored for the degradate 3,5-DCA. The two studies were conducted in
California and North Carolina and are summarized below.
In a study conducted in San Juan Bautista, California, iprodione was applied 8 times to carrots at
1 Ib ai/A/application. Iprodione dissipated with an observed DT50 of 7 days in the 0-15 cm soil
layer of a silt loam soil (pH 7.9-8.0). The degradates RP30228 and RP32490 were recovered
from the 0-15 and the 15-30 cm soil depths. Iprodione and its degradates were not detected
below the 30-cm soil level. RP30228 was a maximum average of 0.47 ppm at 28 days after
treatment, declining only to 0.15 ppm at 538 days. RP32490 was observed at relatively low
levels (<0.09 ppm) in the field. Field spike recoveries of iprodione at this site were 66 to 86%.
In a study conducted in North Carolina, iprodione was applied 8 times to carrots at 1 Ib
ai/A/application. The observed DT50 was less than 3 days in the 0-15 cm soil depth of a loamy
sand soil (soil pH of 6.2 - 6.8). RP30228 and RP32490 were observed only in the 0-15 cm soil
depth. No residues of these degradates or iprodione were detected below 15 cm. The
concentrations of RP30228 were lower (ranging from 0.01 to 0.08 ppm until 492 days).
Recoveries of iprodione field spikes at this site were 66 to 86%.
In aquatic field dissipation studies (MRID 43718301), iprodione was applied twice to flooded
rice paddies at 0.5 Ib/acre at a 15-day interval at two site—one in Waller County TX, and one in
Washington County, MS. Iprodione was applied to the rice foliage at both sites (55% canopy
coverage at TX, 85% at MS). The two sites were flooded for 1 month. The pH of the flood
waters at both sites were in the range for which iprodione readily degrades by hydrolysis. Flood
water dissipation half lives were 3.7 days in Texas and 2.9 days in Mississippi; soil half lives
however were on the order of months. Maximum concentrations observed in both studies were
around 500 ppb. Storage sample recoveries for 3,5-DCA were only 18%, and thus this study is
not suitable for characterizing the formation or persistence of 3,5-DCA. The major degradates
observed at both sites were RP 30228 and RP 37176.
30
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2.4.2 Mechanism of Action
Iprodione is a member of the carboximide fungicides used to control various blights and rots
caused by fungal pathogens. Iprodione causes oxidative damage to fungal cells as well as to
mammalian and fish cells through the production of free oxygen radicals. The chemical has been
demonstrated to bind to the aryl hydrocarbon receptor (AhR) and induce the cytochrome P4so
system in vitro2'3'4 Additionally, iprodione is structurally related to the dichloroanilines as is the
degradate 3,5-dichloroaniline (3,5-DCA). Based on information contained in the Assessment
Tools for the Evaluation of Risk (ASTER) database5, compounds such as DCA are believed to
act through polar narcosis. The acute mode of toxic action for these types of compounds is
generally attributed to narcosis (the lexicologically induced and reversible stages of neural
disruption). The narcosis syndrome elicited by these chemicals is distinct from the syndrome
elicited by compounds thought to act via nonpolar narcosis. Polar narcotics are typically more
toxic than what would be predicted from the nonpolar narcotic Quantitative Structure Activity
Relationship (QSAR).
2.4.3 Use Characterization
Analysis of labeled use information is the critical first step in evaluating the federal action. The
current labels for iprodione represent 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. At this time, there are 42 registered labels for iprodione that are
relevant to uses throughout the United States; 4 of these are for technical formulations and 38 are
for formulated products. While technical products, which contain iprodione of high purity, are
not used directly in the environment, they are used to make formulated products, which can be
applied in specific areas to control fungal blights and rusts. The formulated product labels
legally limit iprodione's potential use to only those sites that are specified on the labels. In
addition to the 38 nationally registered formulated product labels, there are currently 7 special
local needs labels that apply to use of iprodione use in California. The nationally registered
formulated products and special local needs registrations that are included in defining the federal
action for this assessment are provided in Appendix A. The use disclosure memo for iprodione
is provided in Appendix B.
Iprodione is currently registered for use in California for 37 different agricultural crops.
Agricultural uses include almonds, stone fruits, beans, caneberries, bushberries, canola, cole
crops, carrots, cotton, crucifer, garlic, grapes, lettuce, onions, peanuts, potatoes, radish, rutabaga,
strawberries and turnip greens. Applications to agricultural uses can be made via several
Ferraris, M, A. Flora, C. Chiesara, D. Fornasari, H. Lucchetti, L. Marabina, S. Frigerio and S. Radice. 2005.
Molecular mechanism of the aryl hydrocarbon receptor activated by the fungicide iprodione in rainbow trout
(Oncorhynchus mykiss) hepatocytes. Aquatic Toxicology 72: 209 - 220.
3 Radice, S., M. Ferraris, L. Marabini, S. Grande, E. Chiesara. 2001. Effect of iprodione, a dicarboximide
fungicide, on primary cultured rainbow trout (Oncorhynchus mykiss) hepatocytes. Aquatic Toxicology 54: 51 - 58.
4 Long, M. P. Laier, A. M. Vinggaard, H. R. Anderson, J. Lynggaard, E. C. Bonefeld-Jergensen. 2003. Effects of
currently used pesticides in the AhR CALUX assay: comparison between the human TV101L and the rate H4IIE
cell line. Toxicology 194: 77-93.
5 ASTER (Assessment Tools for the Evaluation of Risk) http://cfistage.rtpnc.epa.gov/aster/
-------
different application methods, including ground spray, spray by aircraft, chemigation, soil in
furrow treatment, dip treatment and seed treatment. The maximum single application rate varies
by the specific agricultural use and ranges 0.27-1.37 Ibs a.i./A. Specific application rates
(maximums), numbers of applications per season, application intervals, timing of applications
and application methods for the agricultural uses are provided in Table 10.
It should be noted that some formulated product labels for iprodione allow for the use on ginseng
in California; however, based on analysis of National Agricultural Statistics Service (NASS)
data, ginseng is not grown in California and is therefore, not relevant to this assessment.
32
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Table 10. Agricultural uses of iprodione that are relevant to CA.
Use(s)
almonds
beans
berries1
canola
carrots
cole crops2
cotton
crucifer
garlic
grapes
lettuce
lettuce
onions
peanuts
potatoes
radishes
rutabagas
Stone fruit3
strawberries
Turnip greens
Max
application
rate
(Ibs a.i./A)
0.5
0.2719
1
2
1
0.75
1.3725
1
1
#
applications
/season
4
2
4
5
4
5
1*
5
1
4
4
o
J
5
o
J
4
5
5
2
1
5
Application interval
(days)
again at full bloom, petal
fall, and several weeks
after petal fall
5
14
up to day of harvest
7
up to day of harvest
not applicable
up to day of harvest
not applicable
again at bunch closing,
fruit ripening, prior to
fruit harvest
10
10
14
14
10
not stated
not stated
again at full bloom or
petal fall
not applicable
up to day of harvest
Initial
application
timing
pink bud
bloom
bloom
2-4 leaf stage
foliar
2-4 leaf stage
at planting
2-4 leaf stage
at planting
bloom
3 leaf stage
3 leaf stage
foliar
foliar
foliar
bloom
bloom
bud
bloom
2-4 leaf stage
Application method
ground spray, chemigation, air spray
ground spray, chemigation, air spray
ground spray, chemigation, air spray
ground spray, chemigation, air spray
ground spray, chemigation, air spray
ground spray, chemigation, air spray
soil in-furrow treatment
ground spray, chemigation, air spray
soil in-furrow treatment
ground spray, chemigation, air spray
ground spray, chemigation
air spray
ground spray, chemigation, air spray
ground spray, chemigation
ground spray, chemigation, air spray
ground spray, chemigation, air spray
ground spray, chemigation, air spray
air and ground spray
ground spray, air spray, dip treatment
ground spray, chemigation, air spray
*assumed based on application method
1 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
2 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
33
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Specific crops where iprodione is used as a seed treatment are listed in Table 11, along
with the application rate for seeds (8.333 Ibs a.i./cwt). Table 11 also provides seeding
rates obtained from Extension offices for the crops to which iprodione can be applied as a
seed treatment. When the seeding rates are taken into account with the application rate of
iprodione on seeds, single application rates range 0.125-1.5 Ibs a.i./A, which is generally
lower than when the pesticide is applied directly to a field via ground spray, chemigation
or air spray.
Table 11. Seed treatments of iprodione that are relevant to CA.
Uses
broccoli
Brussels sprouts
cabbage
canola
carrot
cauliflower
kale
kohlrabi
radish
rutabaga
turnip greens
Ib a.i./cwt
8.333
Seeding Rate (cwt/A)
0.0151
0.0152
0.0153
0.084
0.045
0.0153
0.0153
0.053
0.186
0.026
0.023
Lbs a.i./A
0.125
0.125
0.125
0.667
0.333
0.125
0.125
0.417
1.5
0.167
0.167
1http://ucanr.org/freepubs/docs/7211.pdf
2Assume same rate as broccoli, cabbage, cauliflower and kale
3 http://aggie-horticulture.tamu.edu/extension/vegetable/cropguides/
4FromT-REX
5http://www.extension.umn.edu/Distribution/horticulture/DG7196.html#Seeding
6http://ohioline.osu.edu/b672/pdf/Radishes.pdf
In addition, iprodione is registered for several non-agricultural uses, including conifers,
turf grass (golf courses, sod farms and commercial industrial lawns) and ornamentals.
Based on the labels, a maximum single application rate of 22.44 Ibs a.i./A may be made
to ornamentals via drench. Use of iprodione in residential areas (e.g., turf and
ornamentals) is prohibited. Table 12 summarizes non-agricultural uses of iprodione.
Table 12. Non-agricultural uses of iprodione that are relevant to CA.
Use
conifers
ornamentals
ornamentals
turf1
turf2
Max
application
rate (Ibs a.i./A)
1.25
2.805
22.44
8.16
5.44
#
applicatio
ns /season
4
no limit
defined
no limit
defined
2*
4**
Applicatio
n interval
(days)
7
10
14
14
14
Initial
applicatio
n timing
foliar
foliar
after
transplant
foliar
foliar
Application
method
sprayer,
chemigation, drip
ground spray,
chemigation
drench
ground spray
ground spray
*Plus a 3rd application of 5.48 Ibs a.i./A
**Plus a 5th application of 2.04 Ibs a.i./A
1 golf course - greens, tees and aprons
2 golf course, sod farm, commercial industrial lawns
34
-------
It should be noted that iprodione labels indicate that applications to areas adjacent to
water bodies (including lakes, reservoirs, rivers, streams, marshes, natural ponds,
commercial fish ponds and estuaries) should only be made where a 25 foot vegetated
buffer strip exists.
As of 2002, over 460,000 Ibs of iprodione were applied annually to agricultural crops in
the United States; the highest poundage (133,254 Ibs) was applied to cotton. Almonds
(116,979 Ibs), potatoes (57,463 Ibs) and lettuce (54,408 Ibs) represented the uses with
next highest total pounds of iprodione applied. In total, these 4 uses represented over 70%
of the estimated annual agricultural uses of iprodione in the continental US (Figure 2).
The map in Figure 2 was downloaded from a U.S. Geological Survey (USGS), National
Water Quality Assessment Program (NAWQA) website
(http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php?year=02). It
should be noted that this map does not account for non-agricultural uses of iprodione,
such as turf and ornamentals.
IPRODIONE-fungicide
2002 estimated annual agricultural use
Average annual use of
active ingredient
(pounds par square mile of agricultural
land in county)
D no estimated use
D 0.001 to 0.003
D 0.004 to 0.009
D 0.01 to 0.042
D 0.043 to 0.345
• >= 0.346
Crops
cotton
almonds
potatoes
lettuce
dry onions
grapes
peaches
carrots
cherries
nectarines
Total
pounds applied
133254
116979
57463
54408
24562
19097
19084
18930
9973
7688
Percent
national use
27.04
23.74
11.66
11.04
4.9B
3.87
3.87
3.84
2.02
1.56
Figure 2. Average Annual Iprodione Use in continental US in Total Pounds per County in 2002.
35
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Iprodione use information from the California Department of Pesticide Regulation
(CDPR 2007a) is depicted in Figure 3 and shows total iprodione use in California from
from 1997 to 2007 averaged 342,667 Ibs (standard error: ±30,746 Ibs) based on
California Pesticide Use Reports6 (PUR). Compared to the peak use of 572,389 Ibs
reported for 1998, iprodione use in California declined by roughly 47% in 2001 and has
been roughly level since that time. Based on PUR data, total acreage treated in 1998 was
1,348,382 acres; however, acreage treated had declined to 501,033 acres in 2001
representing a 63% decline.
700000
600000
500000
(/)
•o
c
3
S. 400000
1
.2
300000
200000
100000
.572389
421582
•168
1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007
Year
Figure 3. Total annual use of iprodione in California between 1996 - 2007. California Department of
Pesticide Regulation (2007).
6 California Department of Pesticide Regulation. 2007. Summary of Pesticide Use Report Date 2007
Indexed by Chemical, http://www.cdpr.ca.gov/docs/pur/pur07rep/chmrpt07.pdf
36
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Pesticide use information from CDPR (2007a) includes county-level data for various
iprodione uses from 1999-2006. The majority (85%) of this use occurred in the
following counties: Kern, Monterey, Fresno, Stanislaus, Merced, Madera, Tulare, San
Joaquin, Santa Barbara, Ventura, Kings and Los Angeles (Table 13). Past uses of
iprodione include the majority of the uses identified in Table 10 (note that all uses
reported in PUR are not included in Table 14, e.g., blueberry, raspberry, beans). The
average Ibs of iprodione applied per year in California was highest on almonds (39% of
total use) and lettuce (16% of total use) (Table 14). 'Landscape maintenance' is likely to
be the turf use.
Table 13. Average annual Ibs of iprodione applied per county in CA, based on California Department
of Pesticide Registration (CDPR) Pesticide Use Reporting (PUR) Data from 1999 to 2006. This table
includes counties with an average >1000 Ibs iprodione applied per year.
County
KERN
MONTEREY
FRESNO
STANISLAUS
MERCED
MADERA
TULARE
SAN JOAQUIN
SANTA BARBARA
VENTURA
KINGS
LOS ANGELES
BUTTE
SAN LUIS OBISPO
SAN DIEGO
IMPERIAL
ORANGE
COLUSA
GLENN
SANTA CRUZ
SUTTER
YUBA
SANTA CLARA
SAN BENITO
RIVERSIDE
SONOMA
YOLO
Average Ibs/year
53,976
49,068
40,977
26,233
18,223
18,017
15,611
14,730
12,401
9,070
5,311
5,000
4,296
4,287
4,113
4,061
3,986
2,885
2,863
2,614
2,183
,592
,257
,255
,186
,155
,147
% of total
17%
16%
13%
8%
6%
6%
5%
5%
4%
3%
2%
2%
1%
1%
1%
1%
1%
1%
1%
1%
1%
1%
<1%
<1%
<1%
<1%
<1%
37
-------
Table 14. Average annual Ibs of iprodione applied per use in CA, based on California Department of
Pesticide Registration (CDPR) Pesticide Use Reporting (PUR) Data from 1999 to 2006. This table
includes uses with an average >1000 Ibs iprodione applied in CA per year.
Use
almond
lettuce
carrot
grape
peach
strawberry
landscape maintenance
cherry
nectarine
outdoor ornamental
onion
apricot
plum
greenhouse
prune
potato
broccoli
Average Ibs/year
123,756
50,844
21,785
20,907
16,792
14,647
11,494
8,700
8,637
8,447
7,125
5,196
4,042
3,283
3,038
1,512
1,016
% of total
39%
16%
7%
7%
5%
5%
4%
3%
3%
3%
2%
2%
1%
1%
1%
<1%
<1%
The uses considered in this risk assessment represent all currently registered uses in
California according to a review of all current labels. No other uses are relevant to this
assessment. Any reported use not represented on current labels, such as may be seen in
the CDPR PUR database, represent either historic uses that have been cancelled,
misreported uses, or misuse. Historical uses, misreported uses, and misuse are not
considered part of the federal action and, therefore, are not considered in this assessment.
Analysis of the mass of iprodione applied with consideration of the application area
indicates that applications have been made at or above the maximum application rates
identified in Table 10. In situations where the use data indicate higher than maximum
label application rates, the discrepancy is considered to be most likely due to
misreporting.
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 I.
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Final critical habitat for the CRLF was designated by USFWS on April 13, 2006
(USFWS 2006; 71 FR 19244-19346). Further information on designated critical habitat
for the CRLF is provided in Section 2.6.
2.5.1 Distribution
The CRLF is endemic to California and Baja California (Mexico) and historically
inhabited 46 counties in California including the Central Valley and both coastal and
interior mountain ranges (USFWS 1996). Its range has been reduced by about 70%, and
the species currently resides in 22 counties in California (USFWS 1996). The species has
an elevational range of near sea level to 1,500 meters (5,200 feet) (Jennings and Hayes
1994); however, nearly all of the known CRLF populations have been documented below
1,050 meters (3,500 feet) (USFWS 2002).
Populations currently exist along the northern California coast, northern Transverse
Ranges (USFWS 2002), foothills of the Sierra Nevada (5-6 populations), and in southern
California south of Santa Barbara (two populations) (Fellers 2005a). Relatively larger
numbers of CRLFs are located between Marin and Santa Barbara Counties (Jennings and
Hayes 1994). A total of 243 streams or drainages are believed to be currently occupied
by the species, with the greatest 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 4). Recovery units, core areas, and other known occurrences of the CRLF from
the CNDDB are described in further detail in Attachment I, 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.
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Legend
Recovery Units
1. Sierra Nevada Foothills and Central Valley
2. North Coast Range Foothills nd Western
Sacramento River Valley
3. North Coast and North San Francisco Bay
4. South and East San Francisc Bay
5. Central Coast
6. Diablo Range and Salinas Valley
7. Northern Transverse Rang nd Tehachapi
Mountains
Southern Transverse and Peninsular Ranges
G-t
| Recovery Unit Boundaries
Currently Occupied Core Areas
| Critical Habitat
| CNDDB Occurence Sections
County Boundaries Q
I
180 Miles
I
Core Areas
1. Feather River 19.
2. Yuba River- S. Fork Feather River 20.
3. Traverse Creek/Middle Fork/American R. Rubicon 21.
4. Cosumnes River 22.
5. South Fork Calaveras River* 23.
6. Tuolumne River* 24.
7. Piney Creek* 25.
8. Cottonwood Creek 26.
9. Putah Creek - Cache Creek* 27.
10. Lake Berryessa Tributaries 28.
11. Upper Sonoma Creek 29.
12. Petaluma Creek - Sonoma Creek 30.
13. R. Reyes Peninsula 31.
14. Belvedere Lagoon 32.
15. Jameson Canyon - Lower Napa River 33.
16. East San Francisco Bay 34.
17. Santa Clara Valley 35.
18. South San Francisco Bay
* Core areas that were historically occupied by the California red-legged frog are not included in the map
Watsonville Slough-Elkhorn Slough
Carmel River - Santa Lucia
Gablan Range
Estero Bay
Arroyo Grange River
Santa Maria River — Santa Ynez River
Sisquoc River
Ventura River - Santa Clara River
Santa Monica Bay — Venura Coastal Streams
Estrella River
San Gabriel Mountain*
Forks of the Mojave*
Santa Ana Mountain*
Santa Rosa Plateau
San Luis Ray*
Sweetwater*
Laguna Mountain*
Figure 4. Recovery Unit, Core Area, Critical Habitat, and Occurrence Designations for CRLF.
40
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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 5 depicts CRLF annual reproductive timing.
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 = Young Juveniles
Adults and juveniles can be present all year
Figure 5. CRLF Reproductive Events by Month.
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
41
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aquatic phase feeding exclusively in water and consuming diatoms, algae, and detritus
(USFWS 2002). Tadpoles filter and entrap suspended algae (Seale and Beckvar, 1980)
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).
42
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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
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 Attachment I.
'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 (Section 7) 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:
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• Breeding aquatic habitat;
• Non-breeding aquatic habitat;
• Upland habitat; and
• Dispersal habitat.
Further description of these habitat types is provided in Attachment I.
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 I 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 iprodione 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) Alteration of chemical characteristics necessary for normal growth and viability
of juvenile and adult CRLFs.
(3) Significant increase in sediment deposition within the stream channel or pond or
disturbance of upland foraging and dispersal habitat 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.
(4) 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.
(5) Elimination of upland foraging and/or aestivating habitat or dispersal habitat.
(6) Introduction, spread, or augmentation of non-native aquatic species in stream
segments or ponds used by the CRLF.
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(7) Alteration or elimination of the CRLF's food sources or prey base (also
evaluated as indirect effects to the CRLF).
As previously noted in Section 2.1, the Agency believes that the analysis of direct and
indirect effects to listed species provides the basis for an analysis of potential effects on
the designated critical habitat. Because iprodione is expected to directly impact living
organisms within the action area, critical habitat analysis for iprodione 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 iprodione is likely to encompass considerable portions of the
United States based on the use of iprodione on agricultural areas, forest trees and on turf.
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. The Agency's approach to defining the
action area under the provisions of the Overview Document (USEPA 2004) considers the
results of the risk assessment process to establish boundaries for that action area with the
understanding that exposures below the Agency's defined Levels of Concern (LOCs)
constitute a no-effect threshold. For the purposes of this assessment, attention will be
focused on the footprint of the action (i.e., the area where pesticide application occurs),
plus all areas where offsite transport (i.e., spray drift, downstream dilution, etc.) may
result in potential exposure within the state of California that exceeds the Agency's
LOCs.
Deriving the geographical extent of this portion of the action area is based on
consideration of the types of effects that iprodione may be expected to have on the
environment, the exposure levels to iprodione that are associated with those effects, and
the best available information concerning the use of iprodione and its fate and transport
within the state of California. Specific measures of ecological effect for the CRLF that
define the action area include any direct and indirect toxic effect to the CRLF and any
potential modification of its critical habitat, including reduction in survival, growth, and
fecundity as well as the full suite of sublethal effects available in the effects literature.
Therefore, the action area extends to a point where environmental exposures are below
any measured lethal or sublethal effect threshold for any biological entity at the whole
organism, organ, tissue, and cellular level of organization. In situations where it is not
possible to determine the threshold for an observed effect, the action area is not spatially
limited and is assumed to be the entire 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 iprodione. An analysis of labeled uses and review of available product labels
45
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was completed. For those uses relevant to the CRLF, the analysis indicates that, for
iprodione, several agricultural and non-agricultural uses are considered as part of the
federal action evaluated in this assessment (Table 15).
Following a determination of the assessed uses, an evaluation of the potential "footprint"
of iprodione use patterns (i.e., the area where pesticide application occurs) is determined.
This "footprint" represents the initial area of concern, based on an analysis of available
land cover data for the state of California. The initial area of concern is defined as all
land cover types and the stream reaches within the land cover areas that represent
potential iprodione use sites. Specific uses of iprodione that are relevant to the CRLF and
their associated spatial (GIS) land covers used to define the potential footprint of the use
patterns is provided in Table 15. A map representing all the land cover types that make
up the initial area of concern for iprodione is presented in Figure 6
Table 15. Iprodione uses and their respective GIS land covers used to depict the potential "footprint"
of iprodione use patterns considered for this assessment.
GIS Land cover
Orchard/vineyard
agricultural lands
turf
non-urban forests
Uses
almonds, apricots, cherries, grapes, nectarines, peaches, plums, prunes
beans, blackberries, blueberries, broccoli, Brussels sprouts, bushberries,
cabbage, caneberries, carrots, cauliflower, cotton, crucifer, currants,
elderberries, garlic, gooseberries, huckleberries, kale, kohlrabi, lettuce,
loganberry, onions, ornamentals, peanuts, potatoes, radishes, raspberries,
rutabagas, strawberries, turnip (greens)
Commercial/industrial lawns, turf (golf course, lawn)
Forest trees (conifers)
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Potential Iprodione Use - Initial Area of Concern
Legend
^J CA counties
^^| Forest - coniferous only
| Turf use
^J Orchard vineyard
"1 Cultivated
0 35 70 HO
1:5,395.289
210
Compiled from California County boundaries (ESRI, 2002).
USDA Gap Analysis Program Orchard/Vineyard Landcover (GAP)
National Land Cover DataPase (NLCD) (MRLC, 2001)
Map created by US Environmental Protection Agency, Office
of Pesticides Programs, Environmental Fate and Effects Division.
Projection: Alb ers Equal Area Conic US OS, North American
Datum of 1983 (NftD 1983).
I Kilo meters
280
9Q009
Figure 6. Initial area of concern, or "footprint" of potential use, for iprodione.
Once the initial area of concern is defined, the next step is to define the potential
boundaries of the action area by determining the extent of offsite transport via spray drift
and runoff where exposure of one or more taxonomic groups to the pesticide exceeds the
listed species LOCs. In this assessment, transport of iprodione through runoff and spray
47
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drift is considered in deriving quantitative estimates of iprodione exposure to CRLF, its
prey and its habitats. Since this screening-level risk assessment defines taxa that are
predicted to be exposed through runoff and drift to iprodione at concentrations above the
Agency's Levels of Concern (LOG), there is need to expand the action area to include
areas that are affected indirectly by this federal action. Because iprodione is considered
by the EPA as a "likely" carcinogen (see iprodione RED) and because the terminal
metabolite of iprodione, 3,5-DCA was considered to have a genotoxic mode of tumor
induction (based on its similarity to its structural analog />ara-chloraniline which is
carcinogenic in mammals), the action area for iprodione is established as the entire state
of California. Additional analysis related to the intersection of the iprodione action area
and CRLF habitat used in determining the final action area is described in Appendix C.
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."7 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
iprodione (e.g., runoff, spray drift, etc.), and the routes by which ecological receptors are
exposed to iprodione (e.g., direct contact, etc.).
2.8.1 Assessment Endpoints for the CRLF
Assessment endpoints for the CRLF include direct toxic effects on the survival,
reproduction, and growth of the CRLF, as well as indirect effects, such as reduction of
the prey base or modification of its 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. It should be noted
that assessment endpoints are limited to direct and indirect effects associated with
survival, growth, and fecundity, and do not include the full suite of sublethal effects used
to define the action area. According the Overview Document (USEPA 2004), the
Agency relies on acute and chronic effects endpoints that are either direct measures of
impairment of survival, growth, or fecundity or endpoints for which there is a
scientifically robust, peer reviewed relationship that can quantify the impact of the
measured effect endpoint on the assessment endpoints of survival, growth, and fecundity.
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
7 U.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.
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included in Section 4.0 of this document. A summary of the assessment endpoints and
measures of ecological effect selected to characterize potential assessed direct and
indirect CRLF risks associated with exposure to iprodione is provided in Table 16.
Table 16. Assessment Endpoints and Measures of Ecological Effects.
Assessment Endpoint
Measures of Ecological Effects8
Aquatic-Phase CRLF
(Eggs, larvae, juveniles, and adults)3
Direct Effects
1. Survival, growth, and reproduction of CRLF
la. Most sensitive freshwater fish, i.e, channel
catfish (Ictalurus punctatus) acute LCso
Ib. Most sensitive freshwater fish, i.e., fathead
minnow (Pimephales promelas) NOAEC
Indirect Effects and Critical Habitat Effects
1. Survival, growth, and reproduction of CRLF
individuals via indirect effects on aquatic prey food
supply (i.e., fish, freshwater invertebrates, non-
vascular plants)
3. Survival, growth, and reproduction of CRLF
individuals via indirect effects on habitat, cover,
food supply, and/or primary productivity (i.e.,
aquatic plant community)
4. Survival, growth, and reproduction of CRLF
individuals via effects to riparian vegetation
2a. Most sensitive freshwater fish, i.e, channel
catfish, freshwater invertebrate, i.e, waterflea
(Daphnia magna), and aquatic plant EC50, i.e.,
diatom (Skeletonema costatum)
2b. Most sensitive freshwater invertebrate (D.
magna) and fish (P. promelas) chronic NOAEC
3a. Vascular plant (duckweed; Lemna gibba) acute
EC50
3b. Non-vascular plant acute EC50 (diatom; S.
costatum)
No terrestrial plant toxicity data are available for
iprodione.
Terrestrial-Phase CRLF
(Juveniles and adults)
Direct Effects
5. Survival, growth, and reproduction of CRLF
individuals via direct effects on terrestrial phase
adults and juveniles
5a. Most sensitive birdb (Northern bobwhite quail;
Colinus virginianus) acute oral LD50 and subacute
dietary LC50
5b. Most sensitive birdb (C. virginianus) chronic
NOAEC
Indirect Effects and Critical Habitat Effects
6. Survival, growth, and reproduction of CRLF
individuals via effects on terrestrial prey
(i.e., terrestrial invertebrates, small mammals , and
frogs)
7. Survival, growth, and reproduction of CRLF
individuals via indirect effects on habitat (i.e.,
riparian and upland vegetation)
6a. Most sensitive terrestrial invertebrate (honeybee;
Apis mellifera) acute contact LD50 and vertebrate
(laboratory rat; Ratus norvegicus) acute oral LC50
(guideline)
6b. Most sensitive terrestrial invertebrate and
vertebrate (R. norvegicus) chronic NOAEC
No terrestrial plant toxicity data are available for
iprodione.
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.
8 All registrant-submitted and open literature toxicity data reviewed for this assessment are included in
Appendix A.
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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 iprodione 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 and jeopardize the continued existence of the CRLF.
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 iprodione effects data are available. Adverse modification to
the critical habitat of the CRLF includes, but is not limited to, those listed in Section 2.6.
Measures of such possible effects by labeled use of iprodione on critical habitat of the
CRLF are described in Table 17. 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).
50
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Table 17. Summary of Assessment Endpoints and Measures of Ecological Effect for Primary
Constituent Elements of Designated Critical Habitata.
Assessment Endpoint
Measures of Ecological Effect
Aquatic-Phase CRLF 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.
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.
Alteration of other chemical characteristics necessary
for normal growth and viability of CRLFs and their
food source.
Reduction and/or modification of aquatic -based food
sources for pre-metamorphs (e.g., algae)
a. Most sensitive aquatic plant (nonvascular S. costatum
and vascular L. gibbet) EC50
No terrestrial plant toxicity data are available for iprodione.
a. Most sensitive aquatic plant (nonvascular S. costatum
and vascular L. gibba) EC50
b. No terrestrial plant toxicity data are available for
iprodione
a. Most sensitive acute LC50 values for fish (/. punctatus)
and freshwater invertebrate (D. magnd)
b. Most sensitive NOAEC values for fish (P. promelas)
and freshwater invertebrates (D. magnd)
a. Most sensitive aquatic plant (nonvascular S. costatum
and vascular L. gibba) EC50
Terrestrial-Phase CRLF 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
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.
a. No terrestrial plant toxicity data are available for
iprodione Distribution of EC2s values for monocots
(seedling emergence, vegetative vigor, or ECOTOX)
b. Most sensitive food source acute EC50/LC50 and
NOAEC values for terrestrial vertebrates (R. norvegicus)
and invertebrates (A. melliferd), birds (C. virginianus), and
freshwater fish (/. punctatus).
" 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.
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
51
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risk is stressor-linked, where the stressor is the release of iprodione to the environment.
The following risk hypotheses are presumed for this endangered species assessment:
The labeled use of iprodione within the action area may:
• directly affect the CRLF by causing mortality or by adversely affecting growth or
fecundity;
• indirectly affect the CRLF by reducing or changing the composition of food
supply;
• 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;
• 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;
• 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);
• modify the designated critical habitat of the CRLF by reducing the food supply
required for normal growth and viability of juvenile and adult CRLFs;
• 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.
• 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.
• modify the designated critical habitat of the CRLF by altering chemical
characteristics necessary for normal growth and viability of juvenile and adult
CRLFs.
2.9.2 Diagram
The conceptual model is a graphic representation of the structure of the risk assessment.
It specifies the iprodione release mechanisms, biological receptor types, and effects
endpoints of potential concern. The conceptual models for terrestrial and aquatic
exposures are shown in Figure 7 and Figure 8, respectively, which include the
conceptual models for the aquatic and terrestrial PCE components of critical habitat.
52
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Iprodione residues of concern
\ Spray drift!
, ,—Dermal uptake/lnaestiorr^~~
Root
Terrestrial/riparian plants
Exposure
Media
Ingestion
Terrestrial-phase
amphibians
grasses/forbs, fruit, seeds
(trees, shrubs)
Ingestion
Receptors
Ingestion
Birds/terrestrial-
phase amphibians/
reptiles/mammals
Attribute
Change
Individual
organisms
Reduced survival
Reduced growth
Reduced reproduction
uptake^] f
Wet/drv deposition^'
Food chain
Reduction in prey
Modification of PCEs
related to prey availability
Habitat integrity
Reduction in primary productivity
Reduced cover
Community change
Modification of PCEs related to
habitat
Figure 7. Conceptual Model for Iprodione Effects on Terrestrial Phase of the CRLF.
53
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Stressor
Iprodione residues of concern
1 1
r
Source | Spray drift] | Runoff |
\ Groundwater] I Volatilization!
Exposure
Media
Surface water/
Sediment
T
.Wet/dry deposition
Receptors
Uptake/gills
or integument
1
Uptake/gills
or integument
Aquatic Animals
Invertebrates
Vertebrates
Fish/aquatic-phase
amphibians
Inqe^tion
Attribute Individual
Change
organisms
Reduced survival
Reduced growth
Reduced reproduction
Uptake/cell,
roots^ leaves
Aquatic Plants
\lon-vascular
Vascular
t
Inqestion
Food chain
Reduction in algae
Reduction in prey
Modification of PCEs
related to prey availability
1
Habitat integrity
Reduction in primary
productivity
Reduced cover
ommunity change
Modification of PCEs related to
habitat
Figure 8. Conceptual Model for Iprodione Effects on Aquatic Phase of the CRLF.
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 iprodione 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 iprodione is
estimated using the probit dose-response slope and either the level of concern (discussed
below) or actual calculated risk quotient value.
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2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model
2.10.1.1 Measures of Exposure
The environmental fate properties of iprodione along with available monitoring data
indicate that runoff and spray drift are the principle potential transport mechanisms of
iprodione to the aquatic and terrestrial habitats of the CRLF. In addition, iprodione and
3,5-DCA may have the potential to reach ground water. Iprodione is not expected to
volatilize. In this assessment, transport of iprodione through runoff and spray drift is
considered in deriving quantitative estimates of iprodione exposure to CRLF, its prey and
its habitats.
Measures of exposure are based on aquatic and terrestrial models that predict estimated
environmental concentrations (EECs) of iprodione using maximum labeled application
rates and methods of application. The models used to predict aquatic EECs are the
Pesticide Root Zone Model coupled with the Exposure Analysis Model System
(PRZM/EXAMS). The model used to predict terrestrial EECs on food items is T-REX.
These models are parameterized using relevant reviewed registrant-submitted
environmental fate data.
PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, April 2005) are screening
simulation models coupled with the input shell pe5.pl (Aug 2007) to generate daily
exposures and l-in-10 year EECs of iprodione that may occur in surface water bodies
adjacent to application sites receiving iprodione 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, 2-meters deep (20,000 m3 volume) with no outlet. PRZM/EXAMS was used to
estimate screening-level exposure of aquatic organisms to iprodione. The measure of
exposure for aquatic species is the l-in-10 year return peak or rolling mean concentration.
The l-in-10 year peak is used for estimating acute exposures of direct effects to the
CRLF, as well as indirect effects to the CRLF through effects to potential prey items,
including: algae, aquatic invertebrates, fish and frogs. The 1-in-10-year 60-day mean is
used for assessing chronic exposure to the CRLF and fish and frogs serving as prey
items; the 1-in-10-year 21-day mean is used for assessing chronic exposure for aquatic
invertebrates, which are also potential prey items.
Three sets of aquatic EECs were derived: 1) iprodione only; 2) iprodione + all major
degradates; 3) 3,5-DCA only. Iprodione only EECs were derived by modeling
iprodione's chemical properties (e.g., molecular weight, vapor pressure) and half-lives as
well as iprodione application rates. EECs for iprodione + all major degradates were
derived using application rates and chemical properties of iprodione and half-lives that
were representative of the total residues of concern (i.e., iprodione and its major
degradates). EECs for 3,5-DCA were determined using chemical properties of 3,5-DCA
55
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and by assuming that 100% of iprodione applied to a use site is transformed to 3,5-DCA
(i.e., by converting the application rates of iprodione to be specific to 3,5-DCA using the
molecular weight of 3,5-DCA).
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 1.4.1, 10/09/2008).
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 high end residue values from actual field measurements (Hoerger
and Kenega, 1972). For modeling purposes, direct exposures of the CRLF to iprodione
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 iprodione are bound by using the
dietary based EECs for small insects and large insects.
Birds are currently used as surrogates for terrestrial-phase CRLF. However, amphibians
are poikilotherms (body temperature varies with environmental temperature) while birds
are homeotherms (temperature is regulated, constant, and largely independent of
environmental temperatures). Therefore, amphibians tend to have much lower metabolic
rates and lower caloric intake requirements than birds or mammals. As a consequence,
birds are likely to consume more food than amphibians on a daily dietary intake basis,
assuming similar caloric content of the food items. Therefore, the use of avian food
intake allometric equation as a surrogate to amphibians is likely to result in an over-
estimation of exposure and risk for reptiles and terrestrial-phase amphibians. Therefore,
T-REX (version 1.4.1) has been refined to the T-HERPS model (v. 1.0), which allows for
an estimation of food intake for poikilotherms using the same basic procedure as T-REX
to estimate avian food intake.
The spray drift model, AgDRIFT is used to assess exposures of terrestrial phase CRLF
and its prey to iprodione residues of concern deposited on terrestrial habitats by spray
drift. In addition to the buffered area from the spray drift analysis, the downstream extent
of iprodione that exceeds the LOG for the effects determination is also considered.
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,
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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 iprodione to birds is similar to or less than the toxicity to the
terrestrial-phase CRLF. The same assumption is made for fish and aquatic-phase CRLF.
Algae, aquatic invertebrates, fish, and amphibians represent potential prey of the CRLF
in the aquatic habitat. Terrestrial invertebrates, small mammals, and terrestrial-phase
amphibians represent potential prey of the CRLF in the terrestrial habitat. Aquatic, semi-
aquatic, and terrestrial plants represent habitat of CRLF.
The acute measures of effect used for animals in this screening level assessment are the
LD50, LCso 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 LCso is the concentration of a chemical that is
estimated to kill 50% of the test organisms. EC stands for "Effective Concentration" and
the ECso is the concentration of a chemical that is estimated to produce a specific effect in
50% of the test organisms. Endpoints for chronic measures of exposure for listed and
non-listed animals are the NOAEL/NOAEC and NOEC. NOAEL stands for "No
Ob served-Adverse-Effect-Level" and refers to the highest tested dose of a substance that
has been reported to have no harmful (adverse) effects on test organisms. The NOAEC
(i.e., "No-Observed-Adverse-Effect-Concentration") is the highest test concentration at
which none of the observed effects were statistically different from the control. The
NOEC is the No-Observed-Effects-Concentration. For non-listed plants, only acute
exposures are assessed (i.e., EC25 for terrestrial plants and ECso for aquatic plants).
It is important to note that the measures of effect for direct and indirect effects to the
CRLF and its designated critical habitat are associated with impacts to survival, growth,
and fecundity, and do not include the full suite of sublethal effects used to define the
action area. According the Overview Document (USEPA 2004), the Agency relies on
effects endpoints that are either direct measures of impairment of survival, growth, or
fecundity or endpoints for which there is a scientifically robust, peer reviewed
relationship that can quantify the impact of the measured effect endpoint on the
assessment endpoints of survival, growth, and fecundity.
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
iprodione, 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 iprodione 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).
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For this endangered species assessment, listed species LOCs are used for comparing RQ
values for acute and chronic exposures of iprodione directly to the CRLF. If estimated
exposures directly to the CRLF of iprodione resulting from a particular use are sufficient
to exceed the listed species LOG, 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 iprodione resulting from a particular
use are sufficient to exceed the listed species LOG, then the effects determination for that
use is a "may affect." If the RQ being considered also exceeds the non-listed species
acute risk LOG, then the effects determination is a LAA. If the acute RQ is between the
listed species LOG and the non-listed acute risk species LOG, 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 LOG 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 LOG for plants, the
effects determination is "may affect". Further information on LOCs is provided in
Appendix D
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
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 iprodione on par with the acute toxicity endpoint selected for RQ
calculation. To accomplish this interpretation, the Agency uses the slope of the dose
response relationship available from the toxicity study used to establish the acute toxicity
measures of effect for each taxonomic group that is relevant to this assessment. The
individual effects probability associated with the acute RQ is based on the mean estimate
of the slope and an assumption of a probit dose response relationship. In addition to a
single effects probability estimate based on the mean, upper and lower estimates of the
effects probability are also provided to account for variance in the slope, if available.
Individual effect probabilities are calculated based on an Excel spreadsheet tool IECV1.1
(Individual Effect Chance Model Version 1.1) developed by the U.S. EPA, OPP,
Environmental Fate and Effects Division (June 22, 2004). The model allows for such
calculations by entering the mean slope estimate (and the 95% confidence bounds of that
estimate) as the slope parameter for the spreadsheet. In addition, the acute RQ is entered
as the desired threshold.
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2.10.1.4 Data Gaps
There are no acceptable terrestrial plant toxicity data involving exposures to iprodione in
either registrant-submitted or open literature studies.
Little data are available to characterize the fate and effects of 3,5-DCA in the
environment. No data are available to characterize the fate and effects of iprodione's
other major environmental fate degradates.
3.0 Exposure Assessment
3.1 Surface Water Exposure Assessment
3.1.1 Modeling Approach
Aquatic exposures are quantitatively estimated using PRZM/EXAMS for all of assessed
uses using scenarios that represent high exposure sites for iprodione 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.
In order to quantify exposures and effects of iprodione on non-target, aquatic organisms,
EECs are derived for all uses of iprodione that are relevant to CA. These EECs are based
on total residues of concern which include parent iprodione and all degradates that retain
the 3,5-DCA moiety. These total residue EECs are used in combination with effects data
to generate RQs for the CRLF, its prey and its habitat. In the Risk Description (Section
5.2.1.1), additional EECs are generated to characterize exposures to aquatic animals to
iprodione alone and to 3,5-DCA alone. Although 3,5-DCA can also be present in the
environment as a result of degradation of vinclozolin (another fungicide used on turf
grass in CA), EECs for 3,5-DCA presented in this assessment are only relevant to uses of
iprodione. Example input/output files for PRZM/EXAMS are provided in Appendix E.
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3.1.2
PRZM scenarios
PRZM scenarios intended to represent specific uses in CA were used to model those
specific uses. In cases where no PRZM scenario was available for a particular use (i.e.,
for caneberries and bushberries, radish and rutabaga), surrogate scenarios were assigned
(Table 18). Explanations of why surrogates were selected for specific uses are provided
below.
Table 18. PRZM scenario assignments according to uses of iprodione.
Use
Almonds
Beans
Berries1
Canola
Carrots
Cole Crops 2
Cotton
Crucifer
Garlic
Grapes
Lettuce
Onions
Ornamentals
Peanuts
Potatoes
Radishes
Rutabagas
Strawberries
Stone Fruit 3
Turf
Turnip greens
PRZM scenario
CA Almond STD
CA Row Crop RLF
CA Wine Grapes RLF
CA wheat RLF
CA Row Crop RLF
CA Cole Crop RLF
CA Cotton STD
CA Cole Crop RLF
CA Garlic RLF
CA Wine Grapes RLF
CA Lettuce STD
CA Onion STD
CA Nursery
CA Row Crop RLF
CA Potato RLF
CA Onion STD
CA Potato RLF
CA Strawberry (non plastic) RLF
CA Fruit STD
C A Turf RLF
CA lettuce STD
Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries,
loganberries, raspberries
2 specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3apricots, cherries, nectarines, peaches, plums, prunes
For caneberries and bushberries, the CA winegrape scenario was used as a surrogate.
This scenario is intended to represent a field in Northern Costal CA (Sonoma, Napa, Lake
and Mendocino Counties). The meteorological station for this scenario is located in San
Francisco. According to NASS, caneberries are mostly grown in Santa Cruz County and
blueberries are grown in the coastal valley. The meteorological station and the soil of the
CA winegrape scenario are in close proximity to Santa Cruz County (which is to the
south) and overlap in range with the region of blueberry cultivation. Therefore, this
scenario was considered to be a suitable surrogate, since it is expected to have similar
meteorological and soil conditions to fields where caneberries and blueberries are grown
inCA.
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According to USDA, crucifer crops include vegetables in the Brassiceae family
(http://www.ars-grin.gov/npgs/cgc reports/cruciferl201.htm). These include cole crops,
radiccio, arrugala, radish and others. Since crucifer overlaps with cole crops, the CA cole
crop scenario is used to model this use of iprodione.
The CA lettuce scenario was selected to represent production of turnip greens. It is
expected that lettuce and turnip greens have similar cultivation requirements.
The CA onion scenario is intended to represent an onion field in Kern County. This
scenario is used to represent radishes since it represents a root crop similar to onion. The
two crops are potentially grown in similar areas.
The CA potato scenario is used to represent cultivation of potatoes and rutabagas. This
scenario is representative of a field in Kern County, which is to the south of Merced Co.
No NASS data have been located to clarify which counties in CA grow rutabagas.
Therefore, it is assumed that this crop would grow under similar conditions as the potato.
It should be noted that the CA Row Crop scenario is intended to represent production of
carrots, beans and other crops in CA, and is therefore, directly relevant to these uses.
Peanuts are considered row crops and are classified in this category.
The CA wheat scenario was selected to represent production of canola, which is also a
grain crop like wheat. It is expected that wheat and canola have similar cultivation
requirements.
3.1.3 Chemical Specific Model Inputs for Iprodione Residues of Concern
The appropriate chemical-specific PRZM input parameters are selected from reviewed
physical, chemical and environmental fate data submitted by the registrant (Table 5 and
in Table 6) and in accordance with EFED water model input parameter selection
guidance (U.S. EPA 2002). The input parameters for relevant to the fate of iprodione
residues used in PRZM and EXAMS are in Table 19.
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Table 19. PRZM/EXAMS input parameters relevant to the fate of iprodione residues of concern.
Input Parameter
Molecular Wt. (g/mol)
Henry's Law Constant
(atm-m3/mol)
Vapor pressure (torr)
Solubility in water
(mg/L @ pH 7, 20°C)
Hydrolysis half-life
(days)
Aqueous photolysis
half-life (days)
Aerobic Soil
Metabolism Half-life
(days)
Aerobic Aquatic
Metabolism Half-life
(days)
Anaerobic Aquatic
Metabolism Half-life
(days)
Koc (L/kgoc)
Value
330.2
9.0 x 10'9
2.7xlO'7
13
0*
67
0*
0*
0*
553
Comments
Value for iprodione; See Table 5.
Value for iprodione; See Table 5.
Value for iprodione; See Table 5.
Value for iprodione; See Table 5.
Iprodione residues of concern are stable to hydrolysis at pH 7 (MRID
41885401)
Value is representative of iprodione half-life. No major degradates were
observed in available aqueous photolysis study (MRID 41861901).
It is assumed that iprodione residues of concern are stable, based on an
aerobic soil metabolism study indicating that 3,5-DCA (iprodione's terminal
degradate) is stable (MRID 45239201).
Input parameter guidance indicates that in the case that a chemical is stable
to hydrolysis, this parameter should be defined as 2x the aerobic soil
metabolism half-life used in PRZM (which is 0).
In an aerobic aquatic metabolism study (MRIDs 41927601 and 42503801),
iprodione degraded with an observed DT50 of 3-7 days. However, the pH of
the system was 8.5, which is a level at which hydrolysis of iprodione is a
major mechanism of degradation. RP 30228 and RP32490 were observed as
major degradates. Given that concentrations of 3,5-DCA increased
throughout the study, the 30 d study was not necessarily of sufficient
duration to capture the full formation and decline of 3,5-DCA
In an anaerobic aquatic metabolism study, iprodione degraded with an
observed DT50 of 7-14 days in anaerobic silt loam sediment (MRID
41755801); however, it appeared that this was attributed to hydrolysis. A
sterile control showed that iprodione degraded at about the same rate. Thus
degradation of the parent does not appear to be microbially mediated.
Several other degradates of concern were observed in this study.
Mean of Koc values for iprodione and 3,5-DCA (Table 8 and 9).
* A value of 0 indicates that iprodione total residues of concern are stable to degradation.
3.1.4 Use-Specific Model Inputs for Iprodione Residues of Concern
Use specific parameters include application methods and rates, that are based on current
labels (Table 20). For use patterns where both ground and aerial spray applications are
permitted, aerial applications were modeled since aerial applications have higher spray
drift fractions, and thus, higher aquatic EECs. The impact of assuming the higher spray
drift values corresponding to aerial applications on EECs is discuss further in the Risk
Description (Section 5.2.1.1).
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As noted in the use characterization, iprodione labels indicate that applications to areas
adjacent to water bodies (including lakes, reservoirs, rivers, streams, marshes, natural
ponds, commercial fish ponds and estuaries) should only be made where a 25 foot
vegetated buffer strip exists. In order to account for this label language, AgDRIFT was
used to determine the % deposition in the EFED standard pond (used with EXAMS) that
can be attributed to spray drift. For aerial applications, the spray drift fraction is 0.093.
For ground applications, the spray drift fraction is 0.027. For seed treatments, it was
assumed that the drift fraction is 0.
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Table 20. PRZM/EXAMS input parameters relevant to the use of iprodione.
Use(s)
Almonds
Beans
broccoli, Brussels sprouts,
cabbage, cauliflower, kale
(seed treatment)
Berries6
Canola (foliar)
Canola (seed treatment)
Carrot (foliar)
Carrot (seed treatment)
Cole crops7 and Crucifer
(foliar)
conifers
Cotton
Garlic
Grapes
Grapes
kohlrabi (seed treatment)
Max ap
rate (kg
a.i./ha)
0.56
1.12
0.14
1.12
1.12
0.75
1.12
0.37
1.12
1.40
0.30
2.24
1.12
1.12
0.47
# aps/
season
4
2
1
4
5
1
4
1
5
4
I8
1
4
4
1
Minimum
application
interval
(days)1
75
5
not applicable
14
75
not applicable
7
not applicable
75
7
not applicable
not applicable
75
75
not applicable
Initial
application
timing1
pink bud
bloom
at planting
bloom
2-4 leaf stage
at planting
foliar
at planting
2-4 leaf stage
foliar
at planting
at planting
bloom
bloom
at planting
Initial application date2
(brief explanation)
Feb 15 (USDA profile
for CA almonds)
Feb 1 (1 month after crop
emergence)
Dec 15 (2 weeks before
emergence)
April 1 (1 mo nth after
crop emergence)
Jan 1 (emergence date)
Dec 15 (2 weeks before
emergence)
Feb 1 (1 month after crop
emergence)
Dec 15 (2 weeks before
emergence)
Jan 1 (emergence date)
March 15 (arbitrary date
to represent spring)
April 15 (2 weeks before
emergence)
Sept 15 (2 weeks before
emergence)
March 1(1 month after
crop emergence)
March 1(1 month after
crop emergence)
Dec 15 (2 weeks before
emergence)
Application
method(s) 1
ground spray,
chemigation, air spray
ground spray,
chemigation, air spray
seed treatment
ground spray,
chemigation, air spray
ground spray,
chemigation, air spray
seed treatment
ground spray,
chemigation, air spray
seed treatment
ground spray,
chemigation, air spray
sprayer, chemigation,
drip
soil in-furrow
treatment
soil in-furrow
treatment
ground spray,
chemigation, air spray
ground spray,
chemigation, air spray
seed treatment
Spray
drift
fraction3
0.093
0.093
0
0.093
0.093
0
0.093
0
0.093
0.027
0.027
0.027
0.093
0.093
0
CAM4
2
2
4
2
2
4
2
4
2
2
4
4
2
2
4
IPSCND
1
1
NA
1
1
NA
1
NA
1
1
NA
NA
1
1
NA
64
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Use(s)
Lettuce (air ap)
Lettuce (ground ap)
Onion
Ornamentals (drench - 1
application)
Ornamentals (drench - 26
applications)
Ornamentals (foliar- 1
application)
Ornamentals (foliar-26
applications)
Peanut
Potato
Radish (foliar)
Radish (seed treatment)
Rutabaga (foliar)
Rutabaga (seed treatment)
Stone fruit9
Strawberry
turf12 (spring)
turf 12 (fall)
Max ap
rate (kg
a.i./ha)
1.12
1.12
0.84
25.15
25.15
3.14
3.14
1.12
1.12
1.12
1.68
1.12
0.19
1.54
1.12
9.15
9.15
#aps/
season
3
4
5
I10
26 10
I11
26 n
3
4
5
1
5
1
2
1
214
214
Minimum
application
interval
(days)1
10
10
14
14
14
10
10
14
10
75
not applicable
75
not applicable
75
not applicable
14
14
Initial
application
timing1
3 leaf stage
3 leaf stage
foliar
after transplant
after transplant
foliar
foliar
foliar
foliar
bloom
at planting
bloom
at planting
bud
bloom
foliar
foliar
Initial application date2
(brief explanation)
Feb 16 (crop emergence)
Feb 16 (crop emergence)
Feb 16 (1 month after
crop emergence)
March 15 (arbitrary date
to represent spring)
Janl
March 15 (arbitrary date
to represent spring)
Janl
Feb 1 (1 month after crop
emergence)
March 16 (1 month after
crop emergence)
Feb 16 (1 month after
crop emergence)
Jan 1 (emergence date)
March 16 (1 month after
crop emergence)
Feb 1 (2 weeks before
crop emergence)
Feb 15 (1 month after
crop emergence)
Feb 1 (1 month after crop
emergence)
September 15 (arbitrary
date to represent fall)
March 15 (arbitrary date
to represent spring)
Application
method(s) 1
air spray
ground spray,
chemigation
ground spray,
chemigation, air spray
drench
drench
ground spray,
chemigation
ground spray,
chemigation
ground spray,
chemigation
ground spray,
chemigation, air spray
ground spray,
chemigation, air spray
seed treatment
ground spray,
chemigation, air spray
seed treatment
air and ground spray
ground spray, air
spray, dip treatment
ground spray
ground spray
Spray
drift
fraction3
0.093
0.027
0.093
0
0
0.027
0.027
0.027
0.093
0.093
0
0.093
0
0.093
0.093
0.027
0.027
CAM4
2
2
2
2
2
2
2
2
2
2
4
2
4
2
2
2
2
IPSCND
1
1
1
1
1
1
1
1
1
1
NA
1
NA
1
1
1
1
65
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Use(s)
turf13 (spring)
turf13 (fall)
turnip greens (foliar)
turnip greens (seed
treatment)
Max ap
rate (kg
a.i./ha)
6.10
6.10
1.12
0.19
#aps/
season
415
415
5
1
Minimum
application
interval
(days)1
14
14
75
not applicable
Initial
application
timing1
foliar
foliar
2-4 leaf stage
at planting
Initial application date2
(brief explanation)
September 15 (arbitrary
date to represent fall)
March 15 (arbitrary date
to represent spring)
Feb 16 (crop emergence)
Jan 1 (2 weeks before
emergence)
Application
method(s) 1
ground spray
ground spray
ground spray,
chemigation, air spray
seed treatment
Spray
drift
fraction3
0.027
0.027
0.093
0
CAM4
2
2
2
4
IPSCND
1
1
1
NA
NA = not applicable
1 according to label
2 based on label description of timing and PRZM scenario
3 Calculated using AgDRIFT with assumption of 25 foot vegetative buffer
4 CAM = 2 is a foliar application, CAM = 4 is a soil (in-furrow) application. For CAM = 4, assume a 4 cm incorporation depth based on default assumption for
PRZM.
5When minimum application interval is not defined on product labels, it was assumed that a 7-d interval is a reasonable application interval.
6 specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
7 specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
8assumed based on application method (not stated on the labels)
9 specifically: apricots, cherries, nectarines, peaches, plums, prunes
10No limit defined on labels. To bound EECs for the drench application, it was assumed that 1 application represented the minimum number of applications per
year and that 26 represented the maximum number of applications per year (limit of PRZM/EXAMS pe5 shell).
nNo limit defined on labels. To bound EECs for the foliar application, it was assumed that 1 application represented the minimum number of applications per
year and that 26 represented the maximum number of applications per year.
12golf course - greens, tees and aprons
13 golf course, sod farm, commercial industrial lawns
14Plus a 3rd application of 5.48 Ibs a.i./A (6.14 kg a.i./ha)
15Plus a 5th application of 2.04 Ibs a.i./A (2.29 kg a.i./ha)
66
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3.1.5 Modeling Results
The aquatic EECs for the various scenarios and application practices are listed in Table
21. The highest EECs were associated with the use of iprodione on ornamental plants
using drench application and where labels did not specify the maximum number of
applications per year.
Table 21. Aquatic EECs (jig/L) for Iprodione Uses in California.
Crops Represented
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower,
kale (seed treatment)
Berries1
Canola (foliar)
canola (seed treatment)
Carrot (foliar)
Carrot (seed treatment)
Cole Crops 2 and Crucifer (foliar)
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (air application)
Lettuce (ground application)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit 3
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial
lawns) (fall)
Turf (golf course, sod farm, commercial industrial
lawns) (spring)
Turnip greens (foliar)
Peak EECs
171
224
14.6
321
812
43.0
450
16.5
1179
324
8.65
59.8
318
49.1
660
728
269
1575
52050
249
7683
211
281
358
16.0
348
2.17
220
184
1379
829
1529
903
1118
21-day
average EECs
171
223
14.4
319
811
41.9
448
16.2
1179
324
8.62
59.4
316
48.4
658
728
269
1538
51760
246
7654
210
279.1
357
16.0
346
2.17
219
183
1370
826
1520
901
1108
60-day
average EECs
170
222
14.4
317
809
40.7
446
16.2
1179
322
8.59
59.0
315
48.2
655
727
267
1538
51270
246
7609
209
277.1
355
16.0
344
2.17
218
183
1369
821
1519
898
1108
67
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I Turnip greens (seed treatment) | 23.3 | 23.2 | 23.1 |
1 specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries,
loganberries, raspberries
2 specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 specifically: apricots, cherries, nectarines, peaches, plums, prunes
3.1.6 Surface Water Monitoring Data
California-specific monitoring data for iprodione and its degradate of concern, 3,5-DCA,
are available from the United States Geological Survey's (USGS) National Water Quality
Assessment (NAWQA; USGS 2009). These data are summarized below. No data are
available in the CDPR Surface Water Database for iprodione or 3,5-DCA.
Iprodione was detected in 27% of 434 surface water samples taken by USGS in CA from
2001-2009. Of the 434 samples, 9% had an estimated value above 1.42 |ig/L. The
maximum reported concentration was estimated at 141|ig/L. The level of quantification
of iprodione ranged 0.01-1.42 |ig/L. 3,5-DCA was detected in 1.3% of 308 surface water
samples collected from 2001-2009 in CA. The maximum reported concentration of 3,5-
DCA was 0.0268 |ig/L. The level of quantification of 3,5-DCA ranged 0.004-0.012 |ig/L
(USGS 2009).
It should be noted that available monitoring data are not necessarily targeted to detect
maximum environmental concentrations of iprodione or 3,5-DCA, and therefore may not
be representative of peak concentrations of these chemicals present in the field.
Following the 1998 iprodione RED, surface water monitoring was required for iprodione
and the degradate 3,5-DCA. The surface water monitoring program started in 2006 in
watersheds that contained high numbers of golf courses. This program is ongoing and
only preliminary results have been received. The preliminary report did not provide
adequate ancillary information to enable thorough evaluation of the data. Surface water
detections of iprodione were higher with 3 detections greater than 1 |ig/L including 8.8
|ig/L at a golf course pond, 1.1 |ig/L at a golf course pond, and 2.6 jig/L at unknown type
of surface water (identified as a greenhouse). Surface water detections of 3,5-DCA
include 4 |ig/L and 1.5 |ig/L in golf course ponds, along with three other golf course pond
samples less than 1 |ig/L. The iprodione/3,5-DCA assessment may need to be
reevaluated upon receipt of the final monitoring reports.
3.2 Ground Water Exposure Assessment
3.2.1 Modeling Approach
In order to estimate ground water EECs for iprodione residues of concern, Scigrow v2.3
was run with the input parameters provided in Table 22.
68
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Table 22. Input parameters for Scigrow v.2.3 used to represent iprodione residues of
concern.
Input Parameter
Maximum rate/application (Ibs a.i./A)
# applications/year
Koc (mL/g OC)
Soil metabolism half-life (days)
Value
22.44
26
553
10,000
Comments
Based on highest single application rate for iprodione
(drench application to ornamentals)
The label does not specify a maximum number of
applications per year for this use. Based on a minimum
application interval of 14 d, a maximum of 26 applications
may be made per year.
Mean of Koc values for iprodione and 3,5-DCA (tables 8
and 9)
Selected large value to represent stable.
3.2.2 Modeling Results
The resulting ground water EEC was 898 |ig/L. This value is 2 orders of magnitude lower
than the surface water EECs generated for this use (approximately 50,000 |ig/L) using
PRZM/EXAMS, indicating that the surface water EECs represent more conservative
values.
3.2.3 Ground Water Monitoring Data
During 2001-2008, 327 ground water samples contained no detectable levels of
iprodione. 3,5-DCA was detected in 5.7% of 229 ground water samples collected in CA.
The maximum detected concentration of 3,5-DCA was 0.0983 |ig/L (USGS 2009).
In the 2000 vinclozolin RED (vinclozolin has the same 3,5-DCA degradate) the
document identified additional generic data requirements. Under the heading
"Surface/Groundwater Monitoring" the document stated that "registrants for vinclozolin
and iprodione will be issued a Data Call-in [DCI]", separate from the generic Data Call-
in ... requiring surface water and ground water monitoring studies." In turn, ground
water monitoring of iprodione and the degradate 3,5-DCA was added to the registrant's
monitoring requirements. A DCI was issued for a prospective ground water monitoring
study in February 2001. A ground water monitoring program was initiated by the
registrant in conjunction with Suffolk County New York after iprodione was reported in
Suffolk County ground water. This program is ongoing and only preliminary results have
been received. The preliminary report did not provide adequate ancillary information to
enable thorough evaluation of the data. For example, although the report indicates that
samples were taken from private drinking water wells, irrigation wells, vineyard wells,
and golf course wells, the spatial context of the sampling locations were not given;
therefore, it is unknown whether the sampling locations are representative of iprodione
use areas. Additionally, well depths were not given for most of the samples which would
be required in order to evaluate whether these are reasonable sampling wells. For some
of the samples it was not apparent whether the samples were taken from ground water or
from surface water.The intent of the report was to show that work had begun on the
69
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monitoring program rather than to provide conclusions regarding iprodione ground water
issues. However, a cursory review of the reported results indicates that there were
detections of iprodione and 3,5-DCA. All of the reported iprodione ground water
detections were at concentrations less than 1 |ig/L, except for one detection in an
irrigation well that was 5.75 jig/L (well depth not given but water table depth was stated
to be 80 ft). Lower and less frequent concentrations were reported for 3,5-DCA in
ground water, with the maximum concentration of 0.44 |ig/L in a golf course well.
3.3 Terrestrial Animal Exposure Assessment
T-REX (Version 1.4.1) is used to calculate dietary and dose-based EECs of iprodione 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 of iprodione are considered, as discussed
in below.
Terrestrial EECs for foliar formulations of iprodione were derived for the uses
summarized in Table 23. Given that no data on interception and subsequent dissipation
from foliar surfaces is available for iprodione, a default foliar dissipation half-life of 35
days is used based on the work of Willis and McDowell (1987). Use specific input
values, including number of applications, application rate and application interval are
provided in Table 23. An example output from T-REX is available in Appendix F.
70
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Table 23. Input Parameters for Foliar Applications Used to Derive Terrestrial EECs for Iprodione
with T-REX.
Use (Application method)
Almonds
Beans
Berries :
Canola
Carrots
Cole crops2
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground application)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone fruit 3
Strawberries
Turf4
Turf5
Turnip greens
Application
rate
(Ibs a.i./A)
0.5
1.25
0.2719
1
2
1
1
1
0.75
22.44
22.44
2.805
2.805
1
1
1
1
1.3725
1
5.44
8.16
1
Number of
Applications
4
2
4
5
4
5
4
1
5
1
4
o
3
4
5
26
1
26
1
o
5
4
5
5
2
1
4
2
5
Reapplication
Interval
(Days)
7
5
14
7
7
7
7
NA
7
NA
7
10
10
14
14
NA
10
NA
14
10
10
7
7
NA
14
14
7
NA = not applicable
1 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, and raspberries
Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
4 golf course, sod farms, commercial industrial lawns
5 golf course: greens, tees and aprons; applications
T-REX is also used to calculate EECs for terrestrial insects exposed to iprodione.
Dietary-based EECs calculated by T-REX for small and large insects (units of a.i./g) are
used to bound an estimate of exposure to bees. Available acute contact toxicity data for
bees exposed to iprodione (in units of jig a.i./bee), are converted to jig a.i./g (of bee) by
multiplying by 1 bee/0.128 g. The EECs are later compared to the adjusted acute contact
toxicity data for bees in order to derive RQs.
For modeling purposes, exposures of the CRLF to iprodione 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 are assessed using the small
mammal (15 g) which consumes short grass. Upper-bound Kenega nomogram values
71
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reported by T-REX for these two organism types are used for derivation of EECs for the
CRLF and its potential prey (Table 24). Dietary-based EECs for small and large insects
reported by T-REX as well as the resulting adjusted EECs are available in Table 25. An
example output from T-REX v. 1.4.1 is available in Appendix F.
Table 24. Upper-bound Kenega Nomogram EECs for Dietary- and Dose-based Exposures of the
CRLF and its Prey to Iprodione.
Use (Application method)
Almonds
Beans
Berries1
Canola
Carrots
Cole crops2
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground application)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone fruit 3
Strawberries
Turf 4
Turf 5
Turnip greens
EECs for CRLF
Dietary-based
EEC (ppm)
222
257
374
521
444
521
555
37
521
270
444
337
411
314
12502
3029
2095
379
315
411
521
521
347
135
2032
1936
521
Dose-based EEC
(mg/kg-bw)
253
293
426
594
506
594
632
42
594
308
506
383
468
357
14238
3450
2387
431
359
468
594
594
395
154
2315
2205
594
EECs for Prey
(small mammals)
Dietary-based
EEC (ppm)
395
457
664
927
789
927
986
65
927
480
789
598
731
558
22225
5386
3725
673
560
731
927
927
616
240
3613
3443
927
Dose-based EEC
(mg/kg-bw)
376
436
633
884
752
884
941
62
884
458
752
571
697
532
21190
5135
3552
642
534
697
884
884
587
229
3445
3282
884
Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, and raspberries
2 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
4 golf course, sod farms, commercial industrial lawns
5 golf course: greens, tees and aprons
72
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Table 25. EECs (ppm) for Indirect Effects to the Terrestrial-Phase CRLF via Effects to Terrestrial
Invertebrate Prey Items from Iprodione.
Use (Application method)
Almonds
Beans
Berries1
Canola
Carrots
Cole crops2
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground application)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone fruit 3
Strawberries
Turf 4
Turf 5
Turnip greens
Small Insect
222
257
374
521
444
521
555
37
521
270
444
337
411
314
12502
3029
2095
379
315
411
521
521
347
135
2032
1936
521
Large Insect
25
29
42
58
49
58
62
4.1
58
30
49
37
46
35
1389
337
233
42
35
46
58
58
39
15
226
215
58
Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, and raspberries
2 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
3 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
4golf course, sod farms, commercial industrial lawns
5golf course: greens, tees and aprons
In addition, T-REX is used to calculate EECs for small mammals consuming seeds that
have been treated with iprodione. At a rate of 8.333 Ibs a.i./cwt, the mammalian dose is
17,655 mg a.i./kg-bw/day.
73
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3.4 Spray Drift Modeling
In cases where RQs exceed the LOG for terrestrial animals, AgDRIFT was used to
characterize the distance from the edge of the treated field where the risk extends. For
ground applications, this was accomplished using the Tier 1 ground setting, assuming a
high boom and ASAE very fine to fine droplet size distribution (90th percentile of data).
For aerial applications, this was accomplished using the Tier 1 aerial setting, assuming a
ASAE fine to medium droplet size distribution (default).For airblast applications, this
was accomplished using the Tier 1 orchard/airblast setting.These parameter values were
selected to represent the most conservative assumptions allowed by the Tier 1 settings of
AgDRIFT. A terrestrial assessment was conducted to determine the distance from the
edge of the field where the point deposition was below the Ibs a.i./A rate that was
required to result in no LOG exceedances for a taxa of concern (i.e., terrestrial-phase
CRLF and mammals). The results of this spray drift assessment are described in context
of their relative RQ values in the risk description of this assessment.
4.0 Effects Assessment
This assessment evaluates the potential for iprodione 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 effects determination include direct toxic effects on
the survival, reproduction, and growth of CRLF, as well as indirect effects, such as
reduction of the prey base or modification of its habitat. In addition, potential
modification of critical habitat is assessed by evaluating effects to the PCEs, which are
components of the critical habitat areas that provide essential life cycle needs of the
CRLF. Direct effects to the aquatic-phase of the CRLF are based on toxicity information
for freshwater fish, while terrestrial-phase effects are based on avian toxicity data, given
that birds are generally used as a surrogate for terrestrial-phase amphibians. Because the
frog's prey items and habitat requirements are dependent on the availability of freshwater
fish and invertebrates, small mammals, terrestrial invertebrates, and aquatic and
terrestrial plants, toxicity information for these taxa are also discussed. 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 iprodione.
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). Open literature data presented in this assessment
74
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were obtained from ECOTOX information obtained on February 28, 2009. In order to
be included in the ECOTOX database, papers must meet the following minimum criteria:
(1) the toxic effects are related to single chemical exposure;
(2) the toxic effects are on an aquatic or terrestrial plant or animal species;
(3) there is a biological effect on live, whole organisms;
(4) a concurrent environmental chemical concentration/dose or application
rate is reported; and
(5) there is an explicit duration of exposure.
Data that pass the ECOTOX screen are 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 for the effects determination 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, because
quantitative relationships between modifications and reduction in species survival,
reproduction, and/or growth are not available. Although the effects determination relies
on endpoints that are relevant to the assessment endpoints of survival, growth, or
reproduction, it is important to note that the full suite of sublethal endpoints potentially
available in the effects literature (regardless of their significance to the assessment
endpoints) are considered to define the action area for iprodione.
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) are included in Appendix G. Appendix G also includes a
rationale for rejection of those studies that did not pass the ECOTOX screen and those
that were not evaluated as part of this endangered species risk assessment. A detailed
spreadsheet of the available ECOTOX open literature data, including the full suite of
lethal and sublethal endpoints is presented in Appendix H. Appendix I includes a
summary of the human health effects data for iprodione.
In addition to registrant-submitted and open literature toxicity information, reviews of the
Ecological Incident Information System (EIIS), are conducted to further refine the
characterization of potential ecological effects associated with exposure to iprodione.
At this time, no toxicity data are available to characterize the effects of intermediate
metabolites to non-target organisms. Therefore, it is assumed that data available for
iprodione are representative of effects to non-target organisms that may be caused by
these metabolites. Some open literature are available for 3,5-DCA, but it is assumed that
this chemical has a different mode of action compared to iprodione.
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A detailed summary of the available ecotoxicity information for iprodione TGAI
(technical grade active ingredient) and formulated products containing iprodione is
presented in Appendix J.
As discussed previously, iprodione has several registered products that contain multiple
active ingredients. All but one of these products contain iprodione in combination with
the fungicide thiophinate-methyl (CAS 23564-05-8). A single formulated product
contained iprodione co-formulated with trifloxystrobin (CAS 141517-21-7). For the
formulated products containing thiophanate-methyl, rat acute oral toxicity studies
resulted in LD50 values ranging from 4199 to >5000 mg/kg bw. These values are
relatively consistent with the rat acute oral LDso value for the technical grade active
ingredient (LD50=4,468 mg/kg bw) discussed in Section 4.2.2. Based on these toxicity
estimates, iprodione technical and its formulated products are classified as practically
nontoxic to mammals on an acute oral exposure basis. No data were available with
which to evaluate the toxicity of the formulated product containing trifloxystrobin.
4.1 Evaluation of Aquatic Ecotoxicity Studies
Table 26 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 J.
Table 26. Freshwater Aquatic Toxicity Profile for Iprodione.
Assessment
Endpoint
Acute Direct
Toxicity to
Aquatic-Phase
CRLF
Chronic Direct
Toxicity to
Aquatic -Phase
CRLF
Indirect Toxicity
to Aquatic-Phase
CRLF via Acute
Toxicity to
Freshwater
Invertebrates (i.e.
prey items)
Indirect Toxicity
to Aquatic-Phase
CRLF via
Chronic Toxicity
to Freshwater
Invertebrates (i.e.
Species
(scientific
name)
Channel
Catfish
Ictalurus
punctatus
Fathead
Minnow
Pimephales
promelas
Waterflea
Daphnia
magna
D. magna
Toxicity Value
Used in Risk
Assessment
LC50 = 3,100
ug/L
(Probit dose-response
slope=10)**
NOAEC =260
ug/L
EC50 = 240 ug/L
(Probit dose-
response
slope=3.45)
NOAEC = 170
ug/L
Describe effect
(i.e. mortality,
growth,
reproduction)
Mortality
Reduced
Larval Survival
Immobilization
Reduced
Reproduction,
Larval Survival,
Growth
Citation
MRID#
(Author &
Date)
4702540-18
Swigert et
al. 1986
Suprenant
1988a
416420-01
McNamara
1990
404892-01
Surprenant
19886
Study
Classification
Supplemental
Acceptable
Supplemental*
Supplemental
76
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prey items)
Indirect Toxicity
to Aquatic-Phase
CRLF via
Toxicity to Non-
vascular Aquatic
Plants
Indirect Toxicity
to Aquatic-Phase
CRLF via
Toxicity to
Vascular Aquatic
Plants
Navicula
pelliculosa
Lemna
gibba
EC50 =50 ug/L
EC50 >12,640
ug/L
Growth
Growth
416041-11
Giddings
1990
457413-01
Sowig 2002
Supplemental
Supplemental
* study originally classified as invalid due to high control mortality; however, the study has been up-graded to
supplemental.
* *probit dose response slope estimated using the average of slopes for bluegill sunfish (11.8) and rainbow trout (8.2).
Toxicity to aquatic fish and invertebrates is categorized using the system shown in Table
27 (U.S. EPA, 2004). Toxicity categories for aquatic plants have not been defined.
Table 27. Categories of Acute Toxicity for Fish and Aquatic Invertebrates.
LC50 (ppm)
<0.1
>0.1 -1
>1-10
> 10 - 100
>100
Toxicity Category
Very highly toxic
Highly toxic
Moderately toxic
Slightly toxic
Practically nontoxic
4.1.1 Toxicity to Freshwater Fish
Given that no iprodione toxicity data are available for aquatic-phase amphibians;
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 iprodione to the CRLF. Effects to freshwater fish resulting from exposure to iprodione
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).
A summary of acute and chronic freshwater fish data, including data from the open
literature, is provided below.
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4.1.1.1 Freshwater Fish: Acute Exposure (Mortality) Studies
In a 96-hr flow-through study (Swigert et al. 1986) of channel catfish (Ictalurus
punctatus), the NOAEC and LCso are 0.52 and 3.1 mg a.i./L, respectively. Based on
these data, iprodione is classified as moderately toxic to freshwater fish on an acute
exposure basis. The study was classified as supplemental and as not having fulfilled
guideline testing requirements for acute toxicity to freshwater fish because of solubility
issues.
Other estimates of acute toxicity of iprodione are available for bluegill sunfish (Lepomis
macrochims; Sousa 1990a) and for rainbow trout (Oncorhynchus mykiss; Sousa 1990&).
The 96-hr LCso values for bluegill (3.7 mg a.i/L) and rainbow trout (4.1 mg a.i./L) are
relatively consistent with the endpoint used in this assessment, i.e., 96-hr LC50=3.1 mg
a..i./L. Although the dose response curve for channel catfish did not provide a probit
slope estimate, probit dose response slopes are available for bluegill (slope = 11.8) and
rainbow trout (slope = 8.2); the mean of the two slope estimates is 10 (standard error:
±1.8).
All of these studies have been classified as not having fulfilled guideline testing
requirements because measured concentrations were highly variable; higher test
concentrations (typically >2.5 mg/L) used in these studies had precipitates that may have
limited exposure to the test substance. Because of this issue, both the bluegill sunfish
(Sousa 1990a) and the rainbow trout (Souse 1990&) studies were classified as invalid by
the EPA reviewers. However, all of the studies had measured concentrations and
represent less sensitive toxicity data for iprodione. While none of the studies fulfill
guideline testing requirements, the results of these studies provide useful information for
qualitatively describing the sensitivity of aquatic vertebrates to iprodione. It is possible
that actual exposure concentrations, in terms of material that was biologically available,
are lower than what is reported in these studies since the researchers did not centrifuge
and/or filter water samples prior to measuring chemical concentrations. However, as
stated previously, these data do represent the best available data for iprodione.
Formulated product testing with Rovral® 50 WP (50%ai) indicated that the product was
less toxic (96-hr LCso=7,800 mg ai/L; Surprenantl987) than the technical grade active
ingredient.
No data were available in the open literature that were more sensitive than the endpoints
provided through registrant-submitted data.
4.1.1.2 Freshwater Fish: Chronic Exposure (Early Life Stage and
Reproduction) Studies
Based on an early life-stage study (Suprenant 1988a) of fathead minnow (Pimephales
promelas), the NOAEC and LOAEC are 0.26 and 0.55 mg/L, respectively. The LOAEC
is reportedly based on reductions in larval survival; however, the percent reduction is not
reported. The study is classified as acceptable.
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No data were available in the open literature that were more sensitive than the endpoints
provided through registrant-submitted data.
4.1.2 Toxicity to Freshwater Invertebrates
Freshwater aquatic invertebrate toxicity data were used to assess potential indirect effects
of iprodione to the CRLF. Effects to freshwater invertebrates resulting from exposure to
iprodione 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.
A summary of acute and chronic freshwater invertebrate data, including data published in
the open literature, is provided below.
4.1.2.1 Freshwater Invertebrates: Acute Exposure (Mortality) Studies
In a 48-hr study with waterfleas (Daphnia magnet; McNamara 1990), immobilization in
the dilution water control and solvent control averaged 5 and 10%, respectively, which
did not meet the guideline requirements and is classified as supplemental. The 48-hour
ECso was 0.24 mg a.i./L (240 |ig/L) based on measured concentrations, therefore,
iprodione is classified as highly toxic to daphnids on an acute exposure basis. The study
did not fulfill guideline testing requirements due to high mortality in the control (5%) and
solvent control (10%) and according to the EPA reviewer, the study did not establish a
NOAEC. For the purposes of this assessment, the study has been upgraded to
supplemental since current EFED policy states that control mortality should not exceed
10% and acute toxicity studies are not required to establish a NOAEC. Although not
originally reported in the data evaluation record for the McNamara study, the probit dose-
response is 3.45 and is based on a re-analysis of the raw data for the purposes of this
assesssment.
Two additional studies ofD. magna are available; one by Roberts (1977) reported a 48-hr
static LC50 of 382 |ig/L. The second study by Vilkas (1977) reports a 48-hr LC50 of 7200
|ig/L for D. magna. Although the studies by McNamara (1990) and Roberts (1977) have
relatively consistent toxicity estimates for D. magna, the study by Vilkas is an order of
magnitude less sensitive.
In an acute toxicity study identified through ECOTOX, Beketov and Liess 2008
examined the effect of iprodione on blackfly larvae (Simulium latigonium), and the
amphipod (Gammarus pulex). The 96-hr LCso values were 480 |ig/L in S. latigonium and
3460 |ig/L in G. pulex, both of which are less sensitive than D. magna. The study though
relied on dimethylsulfoxide (DMSO) as a co-solvent and it is uncertain as to the extent
that the co-solvent may have affected uptake of the iprodione.
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4.1.2.2 Freshwater Invertebrates: Chronic Exposure (Reproduction)
Studies
In a 21-day study of waterfleas (D. magna; Surprenant 1988&), the test concentrations
varied substantially throughout the test period (i.e., the highest measured concentration in
three treatments was more than twice the lowest in the same concentration). Raw data
(biological, physical, and chemical) were not submitted with the report, therefore, the
reviewer could not verify the author's results. However, based on the study results, the
NOAEC=0.17 mg/L (170 |ig/L) and the LOAEC=0.33 mg/L based on reductions in
survival (26%), growth (mean body length; 7%) and number of young per female (38%).
The study is classified as supplemental and did not fulfill guideline testing requirements.
ECOTOX identified a study by Beketov and Liess 2008 in which iprodione treatment
was observed to significantly affect (increase) the maximum observed percentage of
drifted G. pulex. According to the study, increased drift was detected within 2 hrs after
treatment. Maximum drift percentages were detected 4 hrs after treatment initiation.
During subsequent observation periods (22-48 hrs after treatment was initiated) the drift
responses became less pronounced. Peak drift was initiated at iprodione concentrations
of 366 ng/L; this concentration is roughly 9.5 times lower than the 96-hr LC50 value for
iprodione (3460 |ig/L) in G. pulex. The effect concentration reported in this study is less
sensitive than that for D. magna. Also, there is uncertainty regarding how DMSO may
have affected iprodione uptake.
4.1.3 Toxicity to Aquatic Plants
Aquatic plant toxicity studies were used as one of the measures of effect to evaluate
whether iprodione 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.
Two types of studies were used to evaluate the potential of iprodione to affect aquatic
plants. Laboratory and field studies were used to determine whether iprodione may cause
direct effects to aquatic plants. A summary of the laboratory data for aquatic plants is
provided in Section 4.1.3.1.
4.1.3.1 Aquatic Plants: Laboratory Data
In a 5-day study (Giddings 1990c) of the freshwater diatom Navicula pelliculosa based
on initial measured concentrations, the 120-hour NOAEC, LOAEC, and EC50 for
Navicula exposed to iprodione were 13, 20, and 50 jig ai/1, respectively. The study is
classified as core.
Toxicity data for other aquatic plants include studies on the estuarine/marine diatom
(Skeletonema costatum 120-hr ECso=330 |ig/L; Giddings 1990a), green algae
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(Pseudokirchneriella subcapitata formerly Selenastrum capricornutum 120-hr
ECso= 1,800 |ig/L; Giddings 1990J) and cyanobacteria (Anabaena flos-aquae 120-hr
ECso>860 |ig/L; Giddings 1990e). Compared to the most sensitive toxicity estimate for
aquatic plants, i.e., Navicula EC50=50 |ig/L, the remaining nonvascular plants are
relatively insensitive to iprodione.
In a 7-day acute toxicity study (Sowig 2002) with the aquatic vascular plant duckweed
(Lemna gibbd), the median effect concentration exceeded the highest concentration
tested, i.e, EC5o>12.6 mg/L for number of fronds, plant biomass and growth rate. The
NOAEC for all three measurement endpoints was 12.6 mg/L. The study is classified as
supplemental because of solubility issues associated with the test material.
ECOTOX identified a study by Ma et al. 2002 examining the effects of various
pesticides, including iprodione, on two types of green algae (Chlorella pyrenoidosa and
Scenedesmus obliqnus). Estimated ECso values for C. pyrenoidosa and S. obliqnus are
6.05 mg/L. and 41.9 mg/L, respectively. Both of these values though are less sensitive
than what has been obtained from registrant-submitted studies.
4.2 Toxicity of Iprodione to Terrestrial Organisms
Table 28 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.
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Table 28. Terrestrial Toxicity Profile for Iprodione.
Assessment
Endpoint
Acute Dose-based
Direct Toxicity to
Terrestrial-Phase
CRLF
Acute Dietary -based
Direct Toxicity to
Terrestrial-Phase
CRLF
Chronic Direct
Toxicity to
Terrestrial-Phase
CRLF
Indirect Toxicity to
Terrestrial-Phase
CRLF (via acute
toxicity to
mammalian prey
items)
Indirect Toxicity to
Terrestrial-Phase
CRLF (via chronic
toxicity to
mammalian prey
items)
Indirect Toxicity to
Terrestrial-Phase
CRLF (via acute
toxicity to terrestrial
invertebrate prey
items)
Species
(scientific
Northern
bobwhite
quail
(Colinus
virginianus)
Northern
Bobwhite
Quail
Northern
Bobwhite
Quail
Laboratory
Rat
(Rattus
norvegicus)
Laboratory
Rat
Honey bee
(Apis
me I lifer a)
Toxicity
Value Used in
Risk
Assessment
LD50 =930
mg/kg
LC50 >5,620
mg/kg diet
NOAEL = 324
mg/kg diet
LD50 =4,468
mg/kg bw
NOAEL=300
mg/kg-diet
(18.5
mg/kg/day)
LD50 >120
ug/bee
Describe effect
(i.e. mortality,
growth,
reproduction)
Mortality
Mortality
Reduced
number of eggs
laid; reduced
hatchling body
weight.
Mortality
Decreased body
weight, body
weight gain and
decreased food
consumption
Mortality
Citation
MRID#
(Author &
Date)
Acc# 232703
McGinnis and
Johnson 1973
416041-02
Driscoll et al.
1990
Acc#
00099126
Fink et al.
423063-01
Cummins
00162983
41871601
Kenwood
1991
442620-61
Atkins 1975
Study
Classification
Core
Core
Core
Acceptable
Acceptable
Acceptable
Acute toxicity to terrestrial animals is categorized using the classification system shown
in Table 29 (U.S. EPA, 2004). Toxicity categories for terrestrial plants have not been
defined.
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Table 29. Categories of Acute Toxicity for Avian and Mammalian Studies.
Toxicity Category
Very highly toxic
Highly toxic
Moderately toxic
Slightly toxic
Practically non-toxic
Oral LDSO
< 10 mg/kg
10 - 50 mg/kg
51 -500 mg/kg
501 - 2000 mg/kg
> 2000 mg/kg
Dietary LC50
< 50 ppm
50 - 500 ppm
501- 1000 ppm
1001 - 5000 ppm
> 5000 ppm
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 iprodione; therefore, acute
and chronic avian toxicity data are used to assess the potential direct effects of iprodione
to terrestrial-phase CRLFs.
4.2.1.1 Birds: Acute Exposure (Mortality) Studies
In an acute oral toxicity study (McGinnis and Johnson 1973) with Northern bobwhite
quail (Colinus virginianus) and based on nominal oral doses, the LDso was 930 mg
a.i./kg. No sublethal effects were reported in the study. Based on the results of this
study, iprodione is classified as slightly toxic to Northern bobwhite quail. The study is
classified as acceptable and fulfills the guideline test requirements of an avian single oral
dose LD50 test.
Another more recent study with Northern bobwhite quail resulted in an acute oral
value exceeded the highest concentration tested, i.e., 2000 mg/kg bw, and where no
mortality was observed in any of the treatment groups (Culotta et al. 1990). The more
recent acute oral toxicity study by Culotta et al. (1990) is more consistent with the
available subacute dietary toxicity studies discussed below indicating that iprodione is
practically nontoxic to birds on a subacute dietary exposure basis.
In a subacute dietary toxicity study with Northern bobwhite quail (C. virginianus;
Driscoll et al. 1990) and based upon nominal exposure concentrations, the dietary LCso
of iprodione was greater than 5,620 mg/kg diet, the highest dietary concentration tested.
This value classifies iprodione as practically non-toxic to upland game birds. There was
no effect on body weight and or mortality in the study; as such, the NOAEC is 5620
mg/kg diet. The study is classified as acceptable. Similar results were obtained in a
subacute dietary toxicity study with mallard ducks (Anas platyrhyncos; Driscoll et al.
1990&). The subacute dietary toxicity studies for Northern bobwhite quail (Driscoll et al.
1990a) and for mallard ducks (Driscoll et al. 1990&) both resulted in LCso values greater
than the highest concentration tested, i.e., 5,620 mg/kg diet. In the quail study, 2 birds
83
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were dead in the 5,620 mg/kg diet group while in the mallard study none of the birds
died. The quail study did report dose-depended effects on body weight but no effect on
feed consumption. At the highest treatment level, i.e., 5620 mg/kg diet, average body
weight was roughly 33% less than controls. Although none of the birds in the mallard
study died, body weights appeared to be affected similar to what was observed in the
quail study; mallards at the highest treatment level, i.e., 5620 mg/kg diet, had average
body weights roughly 26% lower than controls.
One study was available in the open literature on the effects of iprodione on liver enzyme
production in Japanese quail (Coturnix coturnix) (Riviere et al. 1983) following sub-
acute dietary exposure at 2000 ppm for 7 days. In the iprodione-treated birds, liver
weights were not significantly different than controls; however, cytocrhome P450 activity
was roughly 4 times greater than controls. Activity of 7-ethoxyresorufin dealkylase was
12 times greater than controls; however, there were no reports of mortality in the treated
birds. While there were sublethal impacts on enzyme activity these effects are not linked
to more apical endpoints.
4.2.1.2 Birds: Chronic Exposure (Growth, Reproduction) Studies
In a avian reproduction study with Northern bobwhite quail (Fink et al. 198 la.),
reproduction was adversely affected by exposure at the 941 mg ai/kg diet level.
Specifically, the study authors' analysis detected a statistically-significant (p<0.05)
reduction in the percentage of eggs laid of maximum laid (39% versus 51% for the
control) and in the mean body weight of hatchlings (6.0 g versus 6.3 g for the control).
Both the reviewer and study authors detected a statistically-significant (p<0.05) reduction
in the percentage of normal hatchlings of eggs set at the 941 mg ai/kg diet level (41%
versus 56% for the controls) and the reviewer's analysis additionally detected a
significant reduction (p=0.009; 19% of control) at the same level in the proportion of
number hatched to live 3-week embryos (Fink et al. 1981&). Based on the results of this
study, the NOAEL and LOAEL are 324 and 941 mg/kg diet, respectively.
No chronic avian toxicity data were identified in the open literature that were more
sensitive than the registrant-submitted data discussed above.
4.2.1.3 Terrestrial-phase Amphibian Acute and Chronic Studies
No data are available on the toxicity of iprodione to terrestrial-phase amphibians.
4.2.2 Toxicity to Mammals
Mammalian toxicity data are used to assess potential indirect effects of iprodione to the
terrestrial-phase CRLF. Effects to small mammals resulting from exposure to iprodione
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).
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The Health Effects Division (HED) risk assessment for iprodione (USEPA 1998c)
concluded that the chemical is associated with toxicity of the liver, adrenals and male and
female reproductive organs with the proposed mode of action as the disruption of
testosterone biosynthesis. Iprodione is also associated with tumors in these organ
systems and the compound is classified as B2 carcinogen given the compound's ability to
cause Leydig cell tumors.
4.2.2.1 Mammals: Acute Exposure (Mortality) Studies
According to the HED mammalian risk assessment (U.S. EPA 1998c), the acute oral
toxicity of iprodione to the rat is 4468 mg/kg bw (Chambers et al. 1992). As such,
iprodione is classified as practically nontoxic to mammals on an acute oral exposure
basis.
As discussed previously, rat acute oral toxicity data are available for the formulated
products of iprodione containing thiophanate-methyl. The LD50 values for the formulated
products ranged from 4,199 to >5,000 mg/kg bw. As such the formulated products
evaluated are classified as practically nontoxic to mammals on a acute exposure basis.
ECOTOX also identified a study on rats by Rankin et al. 1984. examining the
nephrotoxic properties of three fungicides, including iprodione, in male rats. No
significant renal effects were found to result from single doses ranging from 0.4 and 1.0
mmol/kg (114 - 286 mg/kg bw). However, the study contains a significant solvent effect
in controls and was potentially confounded by this effect.
4.2.2.2 Mammals: Chronic Exposure (Growth, Reproduction) Studies
In a 2-generation rat reproduction study where animals were exposed via the diet at dose
levels of 0, 300, 1000 and 2000 ppm, the systemic NOAEL was 300 ppm (18.5
mg/kg/day for two generations and the LOAEL was 1000 ppm (61.4 mg/kg/day) based
on decreased body weight, body weight gain and decreased food consumption. The
reproductivie [offspring] NOAEL was 1000 ppm (76.2 mg/kg/day) and the LOAEL was
2000 ppm (201.2 mg/kg/day) based on decreased pup viability [as evidenced by an
increased number of stillborn pups and decreased survival during postnatal days 0-4,
and decreased pup body weight throughout lactation (USEA 1998b). For the purposes of
this assessment, the systemic NOAEL of 300 ppm (18.5 mg/kg/day) will be used to
estimate risk.
According to the iprodione RED (USEPA 1998b), iprodione is classified as a Group B2,
i.e., it is considered a "likely" carcinogen, based on evidence of tumors in both sexes of
mouse [hepatocellular adenoma/carcinoma] and in the male rat [Leydig cell].
In a study identified through ECOTOX by Gray et al. 1999 examining the effects of
iprodione (100 mg/kg/day) administered by gavage to 14-day old rats through post-natal
day 3, 5-month old male offspring did not exhibit any statistically significant.
abnormalities associated with hermaphrodism, de-masculination, and/or growth.
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4.2.3 Toxicity to Terrestrial Invertebrates
Terrestrial invertebrate toxicity data are used to assess potential indirect effects of
iprodione to the terrestrial-phase CRLF. Effects to terrestrial invertebrates resulting from
exposure to iprodione may also indirectly affect the CRLF via reduction in available
food.
4.2.3.1 Terrestrial Invertebrates: Acute Exposure (Mortality) Studies
Iprodione is classified as practically nontoxic to honeybees (Apis melliferd) on an acute
contact exposure basis with an LD50 value of greater than 120 //g/bee. No bee mortality
was reported at the highest dose tested.
Studies were also identified in ECOTOX. Ladurner et al. 2005 examined the effects of
formulated iprodione (Rovral) on two bee species (Osmia lingaria and Apis melliferd).
For both bee species, delayed (7-day post-treatment) survival rates after oral and contact
exposure to single high dose of iprodione at 125 jig a.i./bee were not statistically different
(p>0.05) to those in the control. However, Huntzinger et al. 2008 examined the effects of
formulated iprodione (Rovral® 50 WP) and other fungicides on adult leafcutter bee
(Megachile rotundatd) via three different exposure methods. The study found that contact
and oral dosing reduced bee survival while topical exposure did not. Contact treatment
showed a significant reduction in survival in males at 30 mg a.i over the 20-day study
period. Bees exposed orally to 5 jig a.i./ jiL also exhibited significant reductions in
survival relative to controls. Because of uncertainty regarding actual exposure levels in
the oral toxicity study, this Huntzinger study provides only qualitative information on the
potential effects of iprodione on bees; given the time frame over which the Huntziner et
al 2008 study examines effects, it may be more representative of effects on chronic
survival rather than acute mortality. The study only provides qualitative evidence of
potential effects though since exposure was not well characterized in the study.
Although ECOTOX identified a study by Pekar (2002) on spiders (Theridion impressum)
as providing useful information, the study was considered unsound for inclusion in this
risk assessment since exposure was not adequately characterized.
In a study by DeNardo et al. 2003, formulated iprodione (Chipco 26GT 23.3% a.i.) at a
rate equivalent to the maximum label rate, did not have a statistically significant effect on
nematode (Steinernema feltiae) survival and/or infectivity under the conditions tested.
This study was essentially an efficacy study and provided qualitative information that the
formulated product was not toxic to the soil nematode. Additionally, Hautier et al. 2005
examined the effects of formulated iprodione (Robral WG) applied at a rate equivalent to
750 g ai./ha on adult parasitic wasps Aphidius rhopalosiphi, adult carabid beetles
Bembidion lamprosm, adult rove beetles Aleochara blilineata, larval ladybird beetles
Adalia bipunctata, and larval hoverflies Episyrphus balteatus. Organims were exposed
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either for 48 hrs or for 2 wks. Under the conditions tested, no significant effects were
noted for any of the species. In a study by Helyer with the predatory midge Aphidoletes
aphidimyza exposure to formulated iprodione (Rovral WP) at a contact level of 500 mg
a.i for 48 hours resulted in less than 15% mortality in adults, less than 5% mortality in
eggs and no mortality in larvae (1st instar).
4.2.3.2 Terrestrial Invertebrates: Chronic Exposure (Growth,
Reproduction) Studies
Although not typically evaluated in ecological risk assessments, there are data suggesting
that iprodione exposure may result in effects on honeybee brood development. In an
unpublished manuscript by Mussen et al. 2008 submitted as an incident report, the
authors describe the effects of Rovral® on honeybee larvae fed at a rate equivalent to 0.5
jig/bee. This rate was based on estimated exposures to honeybees given the label
application rate to almonds of 0.561 kg/ha (0.5 Ibs/Acre). In addition to increased
mortality of larvae, abnormal morphological development in worker pupae was observed.
The authors concluded that adult forage bees could bring compounds such as iprodione
back to the hive where it could be mixed into larval diet and interfere with larval and
pupal development. The data indicate that the formulated product of iprodione is more
toxic to honeybee larvae than adult honeybees; however, there were insufficient data to
determine whether the increased toxicity of the formulated product to honeybees was due
to iprodione, the inerts, or the combination of the two.
Iprodione has been measured in wax samples collected from bee colonies; mean
iprodione residue levels in wax were 48.9±21|ig/kg (vanEnglesdorp et al. 2009). In
unpublished data, Pennsylvania State University researchers have analyzed wax from 208
samples collected from commercial bee colonies; 6.7% of the wax samples contained
iprodione residues with maximum iprodione residues of 636 |ig/kg (personal
communication: Dr. Chris Mullin, Department of Entomology, Pennsylvania State
University, September 2, 2009). These data indicate that iprodione is detected in
honeybee colonies where it can potentially affect brood development.
Although ECOTOX identified a study by Dernoeden et al. 1990 as providing useful
information on the effects of iprodione on nematodes in bluegrass and ryegrass, the study
site had been treated with multiple pesticides and because of the potential confounding
effects of the mixture, the study was not considered in this assessment.
ECOTOX also identified a study by Goettel et al. 1991 examining the effects of
prophylactic formulated iprodione (Rovral 50 WP) application in leafcutter bees
(Megachile rotundatd). The fungicide was incorporated into the natural provisions of the
bee larvae and the effects of the fungicide on growth, mortality and the incidence of
fungal disease chalkbrood (Ascosphaera aggregate) were determined. Under the
conditions tested, the exposure of developing larvae to Rovral 50 WP resulted in
significantly (p<0.01) increased mortality at time of defication and at cocoon completion,
prolonged development time to defication relative to untreated controls; based on
mortality and developmental effects, the NOAEC is 100 ppm and the LOAEC is 1000
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ppm. There was significant uncertainty in this study since the percentage of active
ingredient tested is not specified. As such, this study can only be used qualitatively, but
it supports the concern regarding the potential for adverse effects from exposure of bees
to iprodione and that the effects are not limited to honeybees. Finally, in a study by
Schwartz 1991, the acute effects of formulated iprodione were examined on predatory
mites Ablyseius addoensis; however, exposure to either liquid (0.2 mL/L) or dust
formulation of iprodione resulted in less than 0.1% mortality after 24 hours.
4.2.4 Toxicity to Terrestrial Plants
Terrestrial plant toxicity data are used to evaluate the potential for iprodione 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.
No registrant-submitted terrestrial plant toxicity studies are available for iprodione.
Toxicity studies with terrestrial plants were identified through ECOTOX and are
reviewed briefly below. However, none of the studies provide information that can be
used quantitatively in this assessment. All of the studies were limited by poorly
characterized exposure conditions. While there were conflicting reports in the open
literature on the potential effects of iprodione on terrestrial plants, the weight-of-evidence
collected through the open literature combined with available incident data suggests that
iprodione exposure can result in effects on terrestrial plants.
In a study by Morale and Kurundkar 1989, formulated iprodione (Rovral 50 WP) was
applied at a rate of 0.1% to eggplants (Solanum melongena) and the plants were
evaluated 45 days post-treatment. According to the study, iprodione treatment resulted in
significant increases in leaf area per plant, dry root weight and dry shoot weight.
Gange et al. 1992 provides qualitative information that although formulated iprodione
(Rovral) did not affect seed germination in many of the species on which it was tested, it
did significantly reduce seed germination of the perennial forb English plantain, Plantago
lanceolata at a treatment rate that was considered representative of a field application
rate.
Benson et al. 1992 examined the effects of formulated iprodione (Chipco® 26019 SOW)
on root formation and growth of poinsettias (Euphorbia pulcherrima) plants. The study
examined two different application methods (spraying and rooting cube soaking) and
found that plant height and root initiation were affected by iprodione spraying while only
root initiation was affected by rooting cube soaking. However, in a previous study by
Benson (1991), he reports no significant effect of iprodione on poinsettias growth at the
same exposure concentrations.
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Gadeva and Dimitrov 2008 examined the genotoxicity of several pesticides including
iprodione in the terrestrial plant smooth hawk's beard Crepis capillaris. The study found
that formulated iprodione (Rovral 25 Flo) may act as a aneugen in vitro, i.e., affects cell
division and the mitotic spindle apparatus resulting in the loss or gain of whole
chromosomes inducing an aneuploidy, but that iprodione does not impact meristem
growth or cell proliferation. As an in vitro study, it is unclear how this endpoint may
related to effects in the field.
Yi et al. 2003 examined the effects of iproidone and other fungicides on tubule
germination and tubule morphology in almond (Prunis dulcis) pollen. At 10% and 1% of
the recommended field rate (RFR) 11.2 and 62.9%, respectively, of the iprodione-treated
pollen germinated. As such, all of the iprodione treatments significantly (p=0.05)
affected pollen germination. Pollen tube length was also significantly affected by
iprodione treatment at both the 100% and 10% of RFR treatments. At the 100% RFR, no
pollen germinated and as such there were no tubules; in the 10% RFR, the length of
tubules was roughly 60% less than controls. However, in another study by Yi et al. 2003
examining the effects of formulated iprodione (Rovral) on almond pollen, treatment rates
of 1.2 g/L intended to represent a field application rate of 1.12 kg/ha to almond buds,
iprodione had no significant (p>0.05) effect on pollen tube number or on maximum tube
length.
Rouchard et al. 1984 demonstrated that iprodione significantly affected (increased)
growth of lettuce (Lactuca sativa) over a 32-day post-treatment period. Formulated
iprodione (Rovral) at a rate of 50 g/acre appeared to significantly increase pigment
content in leaves and plant weight relative to controls.
St. Claire et al. 2005 examined the effects of formulated iprodione (Rovral) on
mycorrhizal associations with sugar maple (Acer saccharuni) and then correlated that
association with photosynthetic production. The study focused on the efficacy of
iprodione in controlling fungal infection; however, it does provide qualitative information
that iprodione treatment at a rate of 2 g/m2 significantly affected calcium uptake;
iprodione-treated seedlings accumulating less foliar calcium than controls. It is uncertain
though how this effect relates to the overall functioning of the sugar maple plants.
Enwistle et al. 1981 examined the effects of formulated iprodione (Rovral® 50% WP) on
the germination of salad onion (Allium fistulosum) seeds. According to the study, at 100
g/kg seed treatment level, iprodione did not affect the time at which seeds started to
germinate but caused a 7 - 24% reduction in final germination and a small but
inconsistent increase in the number of abnormal seedlings. Iprodione seed treatment
consistently increased time to 50% generation by up to roughly 3 days. Iprodione had no
effect on the time at which seedlings started to emerge but there was a significant albeit
inconsistent increase in the final percentage.
West et al. 1993 examined the effects of various fungicides, including iprodione, on
mycorrhizal colonization in the roots of winter annual grass Vulpia ciliata ssp. ambigua.
Formulated iprodione was applied to plants using the formulated product Rovral® at a
rate of 0.6 g/m2. Although this study primarily focuses on the efficacy of various
fungicides in controlling root fungus, it measures the effect of iprodione indirectly
through an analysis of covariance. The analysis suggests that when the effects of fungal
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infection are removed, iprodione appears to significantly (p<0.05) affect (reduce) shoot
mass and leaf mass.
Wick and Philp 1985 examined the effects of iprodione on the emergence and growth of
two onion (Allium cepd) cultivars: White Spanish and Goldberg. Iprodione was dosed
using an undisclosed commercial formulation stated to be 50% w.p. at 50, 100, 200 and
400 g product/kg seed. At the seed treatment levels tested, iprodione resulted in
significantly (p<0.05) reduced emergence in both cultivars of onions. Hypocotyl and
radicle growth of both cultivars were also significantly reduced. Iprodione treatment
significantly (p<0.05) reduced field emergence in the Goldberg cultivar at all of the seed
treatment rates tested, but did not reduce emergence at any of the treatment rates for the
White Spanish cultivar. Plant height was only significantly reduced at the highest
concentration.
While there were studies demonstrating the potential effect of iprodione on terrestrial
plants, there were two studies showing that iprodione treatment had not apparent effect
on plants. In a 3-yr study of bentgrass (Agrostispalustris) by Reicher and Throssell 1997
mean clipping weight, carbohydrate concentration of clippings, rooting, mean disease
incidence, earthworm casts, or thatch of plots of creeping bentgrass were not significantly
affected (p>0.05) by weekly iprodione treatments at rates equivalent to 3.05 kg/ha.
Additionally, Gullino et al 1994 demonstrated that formulated iprodione (EXP 1861) soil
drench treatments at 1 - 4 g/m2 did not appear to significantly affect percent emergence or
basil (Ocymum basilicum) fresh weight. Additionally, Olein et al. 1995 examined the
synergistic effects of fungicides and the fertilizer ammonium thiosulphate (ATS) on
peach trees (Prunus persicd) where iprodione was applied as Rovral 4F (2.5 mL/L) at a
rate of 1.58 kg a.i./ha. Although the study was primarily intended to measure the efficacy
of iprodione alone and in combination with ATS, it provided qualitative information that
at the application rate tested, iprodione did not affect the number of burned shoots per
tree.
Although ECOTOX identified a study by Jeffers 1989, the study essentially examines
efficacy at controlling cottonball disease (Monilinia oxycoccf) in cranberry plants and did
not provide information on the potential effects of iprodione on the plants themselves.
4.3 Toxicity of the 3,5-DCA Degradate
Several studies were identified in the open literature for 3,5-DCA. The only data
available for fish in the open literature was a 14-day LCso value of 3900 ug/L for guppies
(Poecilia reticulate) (Maas-Diepeveen and van Leeuwen 1986). These data suggest that
guppies are considerably less sensitive to the 3,5-DCA degradate than other species
tested against the parent compound. Channel catfish exposed to iprodione had an LC50 of
3100 ug/L after 4 days of treatment compared to the LCso of 3900 ug/L for guppies after
exposure to the degradate for roughly 3.5 times longer.
In a 48-hr study with waterfleas (D. magnd) the EC50 was 1120 ug/L (Maas-Diepeveen
and van Leeuwen 1986) and is roughly 5 times less sensitive than the equivalent toxicity
endpoint for waterfleas using the parent compound (48-hr ECso=240 ug/L). A 96-hr
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study of 3,5-DCA with shrimp (Crangon septemspinosa) resulted in an LCso value of
2500 ug/L (McLeese et al. 1979) and is considerably less toxic than the parent
compound. Finally, in a 96-hr study with green algae (Chlorella pyrenoidosa), the ECso
was 7500 ug/L (Maas-Diepeveen and van Leenwen 1986) and is four times less toxic
than the estimate for green algae tested with the parent compound (96-hr ECso =1800
ug/L) and is roughly 33 times less toxic than the most sensitive toxicity estimate for
nonvascular plants (TV. pellicula 96-hr ECso=55 ug/L) tested with the parent compound.
Therefore, based on the weight of evidence provided through the use of (Q)SARs and
toxicity values reported in the open literature, 3,5-DCA is considered at least 4 times less
toxic to aquatic organisms than the parent compound. Based on measured and estimated
toxicity values for 3,5-DCA, the compound would be classified as moderately toxic to
aquatic animals on an acute exposure basis.
Lo et al. 1994 reported the acute effects of 3,5-DCA in male Fisher rats (R. norvegicus).
The study examined the acute effects of changes in chemical form and dosing method of
3,5-DCA on nephrotoxicity in rats and focused on the hydrochloride salt and free base
forms of 3,5-DCA. Different administration methods (oral \po\ and interperitonial
injection [ip]) were also examined along with different carriers. These carriers included
0.9% saline solution, sesame oil, and 25% DMSO in 0.9% saline solution; only the ip
injections relied on DMSO as one of the carriers. Rats were dosed ip with 0.8 mmol 3,5-
DCA/ kg (264 mg/kg) while po injections were 1.5 mmol/kg (495 mg/kg). Although
some effects on the kidneys were observed, there was no acute mortality due to 3,5-DCA
after 48 hours except in the group treated where DMSO was used as a co-solvent. For
treatments with DMSO, there was complete mortality. These results underscore the
concern regarding the selection of co-solvents in toxicity studies and how DMSO can
alter uptake. These study results are consistent with the understanding that iprodione and
presumably its 3,5-DCA is not acutely toxic to mammals on an acute oral exposure basis
though. The relevancy of the effects of DMSO on the ip study to this risk assessment is
uncertain.
A single chronic toxicity value for 3,5-DCA is available through the open literature in
which zebrafish (Brachydario rerid) were exposed for 28 days and resulted in a NOAEC
of 1000 ug/L (1 mg/L) (van Leeuwen et al. 1990) based on survival, hatching and
growth. Analytical measurements for 3,5-DCA were highly uncertain in the study and
the extent of the effect on survival, hatching and growth is not discussed. No invertebrate
chronic toxicity data were available from the open literature for 3,5-DCA. With an
measured NOAEC of 1000 ug/L, 3,5_DCA is less toxic on a chronic exposure basis
compared to the most sensitive chronic toxicity estimate for the parent, i.e., fathead
minnow NOAEC=60 ug/L.
4.4 Endocrine Disruption
Although the EPA has developed a process for determining whether a chemical acts on
endocrine-mediated processes, the Tier I tests of the Endocrine Disruption Screening
Program are only just being implemented. According to the RED document (USEPA
19986) for iprodione, the registrant (Rhone-Poulenc) at the time the RED document was
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written proposed that the mode of action for the production of Ley dig cell tumors was the
disruption of testosterone biosynthesis. Based on HED's assessment, iprodione and its
metabolites appear to modulate Leydig cell steroidogenesis by interfering at the level of
cholesterol transport and/or steroidogenic enzyme activity (USEPA 1998&).
4.5 Incident Database Review
A review of the EIIS database for ecological incidents involving iprodione was
completed on August 31, 2009. The results of this review for terrestrial animal, plant,
and aquatic incidents are discussed below in Sections 4.5.1 through 4.5.3, respectively.
A complete list of the incidents involving iprodione including associated uncertainties is
included as Appendix K. The Avian Incident Monitoring System (AIMS; American
Bird Conservancy 2009) was also reviewed on August 31, 2009, and a single incident
was reported associated with the use of iprodione on a golf course in Virginia. No
incident reports were available for 3,5-DCA.
A total of 19 incidents are reported in the Ecological Incident Information System.
Fourteen of the incidents are from iprodione use on blueberries; except for one incident in
Mississippi, the remainder of the incidents involving blueberries occurred in Georgia.
The nature of the damage to blueberries was not specified in the incident report. Two
incidents were associated with the use of iprodione on turf (golf courses), one in
Louisiana and the other in Virginia. One incident was associated with the use of
iprodione on ornamental plants in Oregon and one incident was associated with an
unspecified agricultural use of iprodione in California.
4.5.1 Terrestrial Animal Incidents
Application of iprodione to an unspecified agricultural area in California (IO 20302-002)
resulted in the death of an unspecified number of honeybees. The incident report
included an unpublished manuscript by Mussen et al. 2008 describing the adverse effects
of Rovral® on honeybee brood development. The certainly of the beekill incident being
related to iprodione is classified as "probable".
Application of iprodione to golf course turf (BOOO177-001) in Arlington, Virginia, in
1992 resulted in the death of a single bluebird (Turdidae sp.). The legality of the use is
not reported and the certainty of it being related to iprodione is classified as "unlikely".
This incident is also captured in the Avian Incident Monitoring System (AIMS; American
Bird Conservancy 2009) where it reports that chlorpyrifos and metalaxyl were also in use
at the time. Given that chlorpyrifos is considerably more toxic to birds than iprodione on
an acute oral and subacute dietary exposure basis, the likelihood that the death of the
bluebird resulted from iprodione is considered low.
4.5.2 Plant Incidents
A total of 15 incidents associated with the use of iprodione resulted in effects on
terrestrial plants. The majority (14) of these incidents were from the use of iprodione on
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blueberries; of these, 8 of the incidents ( IO4027-101, IO4027-001, IO4027-009, IO4027-
013, IO4027-011, IO4027-008, IO4027-002, IO4027-012) took place in Bacon County,
Georgia, 3 (IO4027-003, IO4027-014 and IO4027-005) occurred in Clinch County,
Georgia, 1 (IO4027-007) in Coffee County, Georgia, 1 (IO4027-006) in Ware County,
Georgia and 1 (IO4027-004) in Stone County, Mississippi. All of the incidents involving
blueberries occurred from a registered use of iprodione and have a certainty index that
iprodione was the cause of the index as "highly probable". All of the incidents involving
blueberries resulted in damage to the blueberries plants due to their direct treatment with
iprodione; the extent of damage ranged from 0.26 to 80 acres affected. It is noteworthy
that 10 of the incidents (IO4027-002, IO4027-010, IO4027-008, IO4027-001, IO4027-
009, IO4027-006, IO4027-011, IO4027-003, IO4027-012 and IO4027-007) associated
with blueberries in Georgia occurred on the same date, i.e., April 7, 2003, and two
additional incidents occurred on subsequent days, i.e., incident IO14027-13 on April 17
and incident IO4027-005 on April 18, in 2003.
An incident (IO13636-027) involving ornamental plants in Washington County, Oregon,
resulted in damage to 6 acres of tulips following direct application of iprodione on
February 4, 2002.
4.5.3 Aquatic Animal Incidents
Only a single aquatic incident is reported in the EIIS associated with the registered use of
iprodione on golf course turf (1000910-001) in St. John the Baptist Parish, Louisiana, on
June 7, 1992. The incident involved the death of an unspecified number of golden
shiners (Notemigonus crysoleucas), catfish (Ictaluridae), needlefish (Strongylura exilis),
minnows (Cyprinidae), perch (Percida) and sunfish (Centrarchidae) due to runoff. The
certainty of the incident being related to the application of iprodione to the golf course is
classified as "possible".
5.0 Risk Characterization
Risk characterization is the integration of the exposure and effects characterizations.
Risk characterization is used to determine the potential for direct and/or indirect effects to
the CRLF or for modification to its designated critical habitat from the use of iprodione
in California. 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 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
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concern (LOCs) for each category evaluated (Appendix D). For acute exposures to the
CRLF and its animal prey in aquatic habitats, as well as terrestrial invertebrates, the LOG
is 0.05. For acute exposures to the CRLF and mammals, the LOG is 0.1. The LOG 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 iprodione usage
scenarios and the appropriate aquatic toxicity endpoint from Table 26. Risks to the
terrestrial-phase CRLF and its prey (e.g. terrestrial insects, small mammals and
terrestrial-phase frogs) are estimated based on EECs resulting from applications of
iprodione and the appropriate toxicity endpoint from Table 28.
5.1.1 Exposures in the Aquatic Habitat
5.1.1.1 Direct Effects to Aquatic-Phase CRLF
Direct effects to the aquatic-phase CRLF are based on peak EECs for iprodione residues
of concern 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. Acute and chronic RQ values for freshwater
fish that serve as surrogates for aquatic-phase CRLF are provided in Table 30.
Acute RQs for aquatic-phase CRLF are sufficient to exceed the LOG (0.05) for all
iprodione uses that are applied via ground spray, chemigation or air spray. Acute RQs
for uses that are applied via soil in-furrow treatment (i.e., cotton and garlic) and seed
treatments do not exceed LOCs.
Chronic RQs for aquatic-phase CRLF are sufficient to exceed the LOG (1.0) for the
majority of iprodione uses that are applied via ground spray, chemigation or air spray,
with the exception of almonds, beans, peanuts, stone fruit and strawberries. Chronic RQs
for uses that are applied via soil in-furrow treatment (i.e., cotton and garlic) and seed
treatments do not exceed LOCs.
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Table 30. Summary of Direct Acute and Chronic Effect1 RQs for the Aquatic-phase CRLF Based on
an Acute Channel Catfish 96-hr LCSO of 3,100 jig/L and a Chronic Fathead Minnow NOAEC of 260
jig/L. EECs represent iprodione residues of concern.
Use(s)
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower, kale
(seed treatment)
Berries4
Canola (foliar)
Canola (seed treatment)
Carrots (foliar)
Carrots (seed treatment)
Cole Crops5 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit6
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial
lawns) (fall)
Turf (golf course, sod farm, commercial industrial
lawns) (spring)
Turnip greens (foliar)
Turnip greens (seed treatment)
Peak EEC
(ug/L)
170.8
223.8
14.6
321.0
811.8
43.0
449.5
16.5
1179.0
323.9
8.7
59.8
318.4
49.1
660.1
728.1
269.3
1575.0
52050.0
248.9
7683.0
210.8
281.0
358.2
16.0
348.0
2.2
219.5
183.8
1379.0
829.1
1529.0
903.1
1118.0
23.3
60-d EEC
(ug/L)
169.7
221.7
14.4
317.1
808.8
40.7
446.4
16.2
1179.0
322.3
8.6
59.0
315.3
48.2
654.8
726.6
267.3
1538.0
51270.0
246.1
7609.0
208.7
277.1
355.1
16.0
344.0
2.2
217.5
182.7
1369.0
821.3
1519.0
898.2
1108.0
23.1
Acute
RQ
0.062
0.072
<0.01
0.102
0.262
0.01
0.152
0.01
0.382
0.102
<0.01
0.02
0.102
0.02
0.212
0.232
0.092
0.512
16.792
0.082
2.482
0.072
0.092
0.122
0.01
O.ll2
0.01
0.072
0.062
0.442
0.272
0.492
0.292
0.362
0.01
Chronic
RQ
0.65
0.85
0.06
1.223
3.113
0.16
1.723
0.06
4.533
1.243
0.03
0.23
1.213
0.19
2.523
2.793
1.033
5.923
1973
0.95
29.33
0.80
1.073
1.373
0.06
1.323
0.01
0.84
0.70
5.273
3.163
5.843
3.453
4.263
0.09
1 RQs associated with acute and chronic direct toxicity to the CRLF are also used to assess potential indirect
effects to the CRLF based on a reduction in freshwater fish and frogs as food items.
2 RQ exceeds acute risk to endangered species LOG of 0.05.
3 RQ exceeds chronic risk to endangered species LOG of 1.0.
4 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries,
loganberries, raspberries
5 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
6 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
95
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5.1.1.2 Indirect Effects to Aquatic-Phase CRLF via Reduction in Prey
Non-vascular Aquatic Plants
Indirect effects of iprodione to the aquatic-phase CRLF (tadpoles) via reduction in non-
vascular aquatic plants in its diet are based on peak EECs for iprodione residues of
concern relevant to the standard pond and the lowest toxicity value (ECso) for aquatic
non-vascular plants (i.e., ECso for Navicula pelliculosa = 50 |ig/L). RQs for non-
vascular plants are sufficient to exceed the LOG (1.0) for all iprodione uses that are
applied via ground spray, chemigation or air spray. The RQ for soil in-furrow treatment
of garlic also exceeds the LOG. RQs for soil in-furrow treatment to cotton and all seed
treatments are below the LOG (Table 31).
Aquatic Invertebrates
Indirect acute effects to the aquatic-phase CRLF via effects to aquatic invertebrates
(prey) in aquatic habitats are based on peak EECs for iprodione residues of concern in the
standard pond and the lowest acute toxicity value for freshwater invertebrates, i.e., D.
magna 48-hr ECso=240 |ig/L. For chronic risks, 21-day EECs and the lowest chronic
toxicity value for invertebrates (D. magna NOAEC=170 |ig/L) are used to derive RQs.
Acute RQs for aquatic invertebrates exceed the LOG for all uses of iprodione, except
cotton (in-furrow) and seed treatments to rutabagas and turnip greens. Chronic RQs
except the LOG for all uses of iprodione, except cotton (in-furrow) and seed treatments of
broccoli, Brussels sprouts, cabbage, cauliflower, kale, carrots, kohlrabi, radishes,
rutabagas and turnip greens. All RQs for uses where iprodione is applied via ground
spray, chemigation or aerial spray are sufficient to exceed acute and chronic LOCs
(Table 32)
Fish and Frogs
Fish and frogs also represent potential prey items of adult aquatic-phase CRLFs. RQs
associated with acute and chronic direct toxicity to the CRLF (Table 30) are used to
assess potential indirect effects to the CRLF based on a reduction in freshwater fish and
frogs as food items. As noted above, acute RQs for aquatic-phase CRLF are sufficient to
exceed the LOG (0.05) for all iprodione uses that are applied via ground spray,
chemigation or air spray. Chronic RQs for aquatic-phase CRLF are sufficient to exceed
the LOG (1.0) for the majority of iprodione uses that are applied via ground spray,
chemigation or air spray, with the exception of almonds, beans, peanuts, stone fruit and
strawberries. Acute and chronic RQs for uses that are applied via soil in-furrow treatment
(i.e., cotton and garlic) and seed treatments do not exceed LOCs.
96
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Table 31. Summary of RQs Used to Estimate Indirect Effects to the CRLF via Effects to Non-
Vascular Aquatic Plants (diet of CRLF in tadpole life stage and habitat of aquatic-phase CRLF)
Based on an EC50 of 50 jig/L for Navicula pelliculosa. EECs represent iprodione residues of concern.
Use(s)
Almonds
Beans
broccoli, Brussels sprouts, cabbage, cauliflower, kale (seed treatment)
Berries2
Canola (foliar)
Canola (seed treatment)
Carrots (foliar)
Carrots (seed treatment)
Cole Crops3 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit4
Strawberries
turf (golf course - greens, tees and aprons) (fall)
turf (golf course - greens, tees and aprons) (spring)
turf (golf course, sod farm, commercial industrial lawns) (fall)
turf (golf course, sod farm, commercial industrial lawns) (spring)
turnip greens (foliar)
turnip greens (seed treatment)
Peak EEC
(HS/L)
170.8
223.8
14.6
321.0
811.8
43.0
449.5
16.5
1179.0
323.9
8.7
59.8
318.4
49.1
660.1
728.1
269.3
1575.0
52050.0
248.9
7683.0
210.8
281.0
358.2
16.0
348.0
2.2
219.5
183.8
1379.0
829.1
1529.0
903.1
1118.0
23.3
RQ
3.421
4.481
0.29
6.421
16.241
0.86
8.991
0.33
23.61
6.481
0.17
1.201
6.371
0.98
13.21
14.61
5.391
31.51
10411
4.981
153.71
4.221
5.621
7.161
0.32
6.961
0.04
4.391
3.681
27.61
16.61
30.61
18.11
22.41
0.47
1 Exceeds risk to aquatic plant LOG of 1.0
2 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries,
loganberries, raspberries
3 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
97
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Table 32. Summary of Acute and Chronic RQs Used to Estimate Indirect Effects to the CRLF via
Direct Effects on Aquatic Invertebrates as Dietary Food Items (prey of CRLF juveniles and adults in
aquatic habitats) Based on an Acute 48-hr EC50 and Chronic NOAEC for Daphnia magna of 240
Eig/L And 170 iig/L, respectively. EECs represent iprodione residues of concern.
Use(s)
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower, kale (seed
treatment)
Berries 4
Canola (foliar)
Canola (seed treatment)
Carrots (foliar)
Carrots (seed treatment)
Cole Crops 5 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit 6
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial lawns) (fall)
Turf (golf course, sod farm, commercial industrial lawns) (spring)
Turnip greens (foliar)
Turnip greens (seed treatment)
Peak EEC
(Mg/L)
170.8
223.8
14.6
321.0
811.8
43.0
449.5
16.5
1179.0
323.9
8.7
59.8
318.4
49.1
660.1
728.1
269.3
1575.0
52050.0
248.9
7683.0
210.8
281.0
358.2
16.0
348.0
2.2
219.5
183.8
1379.0
829.1
1529.0
903.1
1118.0
23.3
21-d EEC
(Mg/L)
170.7
222.8
14.4
319.0
810.7
41.9
448.4
16.2
1179.0
323.7
8.6
59.4
316.4
48.4
658.0
727.9
269.2
1538.0
51760.0
246.1
7654.0
209.8
279.1
357.1
16.0
346.0
2.2
218.5
182.8
1370.0
826.1
1520.0
901.2
1108.0
23.2
Acute
RQ
0.712
0.932
0.062
1.342
3.382
0.182
1.872
0.072
4.912
1.352
0.04
0.252
1.332
0.202
2.752
3.032
1.122
6.562
2172
1.042
32.02
0.882
1.172
1.492
0.072
1.452
0.01
0.912
0.772
5.752
3.452
6.372
3.762
4.662
0.10
Chronic
RQ
l.OO3
1.313
0.08
1.883
4.773
0.25
2.643
0.10
6.943
1.903
0.05
0.35
1.863
0.28
3.873
4.283
1.583
9.053
3053
1.453
45.03
1.233
1.643
2.103
0.09
2.043
0.01
1.293
1.083
8.063
4.863
8.943
5.303
6.523
0.14
:RQs associated with acute and chronic direct toxicity to the CRLF are also used to assess potential indirect effects
to the CRLF based on a reduction in freshwater fish and frogs as food items.
2RQ > acute risk ton endangered species LOG of 0.05.
3RQ> chronic risk LOC of 1.0
4Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries,
raspberries
Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
Specifically: apricots, cherries, nectarines, peaches, plums, prunes
98
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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 effects 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
ECso values, rather than NOAEC values, were used to derive RQs.
As noted above, RQs for non-vascular plants are sufficient to exceed the LOG (1.0) for
all iprodione uses that are applied via ground spray, chemigation or air spray. The RQ
for soil in-furrow treatment of garlic also exceeds the LOG. RQs for soil in-furrow
treatment to cotton and all seed treatments are below the LOG (Table 33).
For vascular plants, the EEC for the high-end use scenario for drench applications to
ornamentals is above the absolute value of the (non-definitive) EC50 for L. gibba. All
EECs, are well below the non-definitive EC50, resulting in no LOG exceedances for any
use except drench applications to ornamentals (Table 33).
99
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Table 33. Summary of RQs Used to Estimate Indirect Effects to the CRLF via Effects to aquatic
habitat. Based on an EC50 of 50 jig/L for Navicula pelliculosa (algae) and an EC50 of EC50 >12,640
Hg/L for Lemna gibba (vascular). EECs represent iprodione residues of concern.
Use(s)
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower, kale (seed
treatment)
Berries2
Canola (foliar)
Canola (seed treatment)
Carrots (foliar)
Carrots (seed treatment)
Cole Crops3 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit4
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial lawns) (fall)
Turf (golf course, sod farm, commercial industrial lawns)
(spring)
Turnip greens (foliar)
Turnip greens (seed treatment)
Peak
EEC
(Mg/L)
170.8
223.8
14.6
321.0
811.8
43.0
449.5
16.5
1179.0
323.9
8.7
59.8
318.4
49.1
660.1
728.1
269.3
1575.0
52050.0
248.9
7683.0
210.8
281.0
358.2
16.0
348.0
2.2
219.5
183.8
1379.0
829.1
1529.0
903.1
1118.0
23.3
Algae
RQ
3.421
4.481
0.29
6.421
16.21
0.86
8.991
0.33
23.61
6.481
0.17
1.201
6.371
0.98
13.21
14.61
5.391
31.51
10411
4.981
153.71
4.221
5.621
7.161
0.32
6.961
0.04
4.391
3.681
27.61
16.61
30.61
18.11
22.41
0.47
Vascular
Aquatic Plant
RQ
0.01
0.02
O.01
O.03
O.06
0.01
O.04
O.01
O.09
0.03
O.01
0.01
0.03
O.01
0.05
O.06
0.02
0.12
<4.U1
O.02
0.61
O.02
0.02
0.03
O.01
0.03
O.01
0.02
0.01
O.ll
O.07
O.12
0.07
0.09
O.01
Exceeds risk to aquatic plant LOG of 1.0
2 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
3 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
100
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5.1.2 Exposures in the Terrestrial Habitat
5.1.2.1 Direct Effects to Terrestrial-phase CRLF
As previously discussed in Section 3.3, potential direct effects to terrestrial-phase CRLFs
are based on foliar applications of iprodione.
Potential direct acute effects to the terrestrial-phase CRLF are derived by considering
dose- and dietary-based EECs modeled in T-REX for a small bird (20 g) consuming
small invertebrates and acute oral and subacute dietary toxicity endpoints for avian
species.
Potential direct chronic effects of iprodione to the terrestrial-phase CRLF are derived by
considering dietary-based exposures modeled in T-REX for a small bird (20g) consuming
small invertebrates. Chronic effects are estimated using the lowest available toxicity data
for birds. EECs are divided by toxicity values to estimate chronic dietary-based RQs.
Acute dose-based RQ values based on a Northern bobwhite quail acute oral LD50 of 930
mg/kg bw exceed the acute risk to listed species LOG (RQ>0.1) for all of the uses
evaluated except cotton (Table 34). Iprodione is practically nontoxic to birds and to the
terrestrial-phase amphibians for which they serve as surrogates on a sub-acute dietary
exposure basis with a Northern bobwhite quail dietary LC5o>5,620 mg/kg diet; however,
EECs are sufficiently high to result in LOG exceedances for iprodione uses on conifers,
ornamental plants and turf. Chronic dietary-based RQ values exceed the chronic risk
LOG (RQ>1) for all of the uses evaluated except for almonds, beans, cotton, garlic,
onions, peanuts and strawberries. Based on exceedances of the acute risk to listed species
LOG and the chronic risk LOG, iprodione may directly affect the terrestrial-phase of the
CRLF.
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Table 34. Summary of Acute Dose- and Dietary-based RQs and Chronic Dietary-based RQ Values
Used to Estimate Direct Effects to the Terrestrial-phase CRLF (non-granular application).
Use
Almonds
Beans
Berries 6
Canola
Carrots
Cole Crops 7
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onion
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potato
Radish
Rutabaga
Stone Fruit8
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Dose-based
Acute
RQ1
0.384
0.444
0.644
0.894
0.734
0.894
0.944
0.06
0.894
0.464
0.754
0.574
0.704
0.534
21.34
5.15d
3.564
0.644
0.544
0.704
0.894
0.894
0.594
0.234
5.294
3.454
0.894
Dietary-based
Acute
RQ2
O.04
<0.05
<0.07
O.09
<0.08
<0.09
<0.104
<0.01
O.09
<0.05
<0.08
<0.06
<0.07
O.06
<2.224
<0.544
<0.374
<0.07
O.06
<0.07
<0.08
<0.09
<0.06
O.02
<0.344
<0.364
<0.09
Dietary-based
Chronic RQ3
0.69
0.79
1.15s
1.61s
1.37s
1.61s
1.71s
0.11
1.61s
0.83
1.37s
1.04s
1.27s
0.97
38.6s
9.35s
6.47s
1.17s
0.97
1.27s
1.46s
1.61s
1.07s
0.42
5.98s
6.27s
1.61s
Based on dose-based EEC and iprodione Northern bobwhite quail acute oral LD50 = 930 mg/kg-bw
2Based on dose-based EEC and iprodione Northern bobwhite quail subacute dietary LC50 >5,620 mg/kg-diet
3Based on dietary-based EEC and iprodione Northern bobwhite quail NOAEC = 324 mg/kg-diet.
4 RQ > acute risk to endangered species LOG of 0.1.
5RQ> chronic risk LOC of 1.0
^Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
8Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5.1.2.2 Indirect Effects to Terrestrial-Phase CRLF via Reduction in
Prey
Terrestrial Invertebrates
In order to assess the risks of iprodione to terrestrial invertebrates, which are considered
prey of CRLF in terrestrial habitats, the honey bee is used as a surrogate for terrestrial
invertebrates. The toxicity value for terrestrial invertebrates is calculated by multiplying
the lowest available acute contact LD50 of >120 jig a.i./bee by 1 bee/0.128g, which is
based on the weight of an adult honey bee. EECs (jig a.i./g of bee) calculated by T-REX
for small and large insects are divided by the calculated toxicity value for terrestrial
102
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invertebrates, which is >938 jig a.i./g of bee. Iprodione is classified as practically
nontoxic to bees on an acute contact exposure basis since the 96-hr LD50 is greater than
the highest dose tested, i.e., 120 jig a.i./bee. As such, all of the RQ values are less than
the calculated values that range from <0.04 to <13.3 for small insects and from <0.004 to
<1.48 for large insects (Table 35). For all of the uses except treatments to turf (golf
courses and sod) and ornamental plants, all of the maximum EECs are below the
treatment level where no mortality was observed in the acute contact toxicity study.
Although there was no mortality at the highest dose tested in the acute contact toxicity
study with honeybees, there is uncertainty whether terrestrial invertebrates may be
affected at the exposure concentrations estimated for iprodione uses on turf and
ornamental plants. Because of this uncertainty, iprodione may affect the CRLF via
reduction in terrestrial invertebrate prey items.
103
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Table 35. Summary of RQ Used to Estimate Indirect Effects to the Terrestrial-phase CRLF via
Direct Effects on Terrestrial Invertebrates as Dietary Food Items.
Use (Application method)
Almonds
Beans
Berries4
Canola
Carrots
Cole crops 5
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground application)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanut
Potato
Radish
Rutabaga
Stone fruits 6
Strawberry
Turf (golf course, sod farms, commercial
industrial lawns)
Turf (golf course: greens, tees and aprons)
Turnip greens
Small
Insect
EEC
(ppm)
222
257
374
521
444
521
555
37
521
270
444
337
411
314
12502
3029
2095
379
315
411
521
521
347
135
2032
1936
521
Large Insect
EEC (ppm)
25
29
42
58
49
58
62
4.1
58
30
49
37
46
35
1389
337
233
42
35
46
58
58
39
15
226
215
58
Small Insect
RQ1 Value
O.24
O.27
0.40
O.56
0.47
O.56
O.59
0.04
O.56
0.29
0.47
O.36
0.44
O.33
<13.33
<3.233
<2.233
0.40
O.34
0.44
0.56
O.56
0.37
O.14
<2.163
<2.063
0.56
Large Insect
RQ2 Value
O.03
O.03
0.04
O.06
0.05
O.06
O.07
0.004
O.06
0.03
0.05
O.04
0.05
O.04
<1.483
0.36
O.25
0.04
O.04
0.05
0.06
O.06
0.04
O.02
O.24
0.23
0.06
RQ calculated by dividing small insect EEC by 938 ug/g of bee
RQ calculated by dividing large insect EEC by 938 ug/g of bee
3EEC exceeds the highest equivalent concentration where no mortality was observed in acute honeybee contact toxicity test.
4Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
^Specifically: apricots, cherries, nectarines, peaches, plums, prunes
Mammals
Risks associated with ingestion of small mammals by large terrestrial-phase CRLFs are
derived for dietary-based and dose-based exposures modeled in T-REX for a small
mammal (15g) consuming short grass. Acute and chronic effects are estimated using the
most sensitive mammalian toxicity data. EECs are divided by the toxicity value to
estimate acute and chronic dose-based RQs as well as chronic dietary-based RQs. Acute
dose-based RQ values range from 0.01 to 2.16 (Table 36); uses of iprodione on conifers,
104
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ornamental plants and turf (sod and golf courses) exceed the acute risk to listed species
LOG of 0.1. Chronic dose-based RQ values range from 1.53 to 521 across all of the uses
evaluated while chronic dietary-based RQ values range from 0.22 to 74.1 (Table 36).
With the exception of iprodione use on cotton where chronic dietary-based RQ values
were below the chronic risk LOG of 1.0, all of the other uses exceed the chronic risk
LOG. When chronic, dietary-based exposures are considered for iprodione to mammals
consuming treated seeds, the RQ is 278, which exceeds the LOG (1.0). Based on
exceedances of the acute risk to listed species LOG and the chronic risk LOG, iprodione
may indirectly affect the CRLF via reduction in small mammal prey items.
Table 36. Summary of Acute and Chronic RQs* Used to Estimate Indirect Effects to the Terrestrial-
phase CRLF via Direct Effects on Small Mammals as Dietary Food Items (non-granular application).
Use
Almonds
Beans
Berries 6
Canola
Carrots
Cole Crops 7
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onion
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potato
Radish
Rutabaga
Stone Fruit 8
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Acute Dose-based
RQ1
0.04
0.04
0.06
0.09
0.08
0.09
0.104
0.01
0.09
0.05
0.08
0.06
0.07
0.05
2.164
0.524
0.364
0.07
0.05
0.07
0.08
0.09
0.06
0.02
0.334
0.354
0.09
Chronic Dose-
based RQ2
9.25s
10.7s
15.6s
21.7s
18.5s
21.7s
23.1s
1.53s
21.7s
11.3s
18.5s
14.3s
17.1s
13.1s
521s
126s
87.4s
15.8s
13.1s
17.1s
19.7s
21.7s
14.5s
5.63s
80.7s
84.7s
21.7s
Chronic Dietary-
based RQ3
1.32s
1.52s
2.21s
3.09s
2.63s
3.09s
3.29s
0.22
3.09s
1.60s
2.63s
1.99s
2.44s
1.86s
74.1s
18.0s
12.4s
2.24s
1.87s
2.44s
2.80s
3.09s
2.05s
0.80
11.5s
12.0s
3.09s
Based on dose-based EEC and iprodione rat acute oral LD50 = 4,468 mg/kg-bw
2Based on dose-based EEC and iprodione rat NOAEL = 18.5 mg/kg-bw.
3Based on dietary-based EEC and iprodione rat NOAEC = 300 mg/kg-diet.
4 RQ > acute risk to endangered species LOG of 0.1.
5 RQ> chronic risk LOC of 1.0
^Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
8Specifically: apricots, cherries, nectarines, peaches, plums, prunes
105
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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. Based on
exceedances of the acute risk to listed species and chronic risk LOCs, iprodione may
directly affect terrestrial-phase amphibians that may serve as prey for CRLF; see Section
5.1.2.1 and associated table (Table 34) for results. As such, iprodione may indirectly
affect the CRLF via reduction in frogs as prey items.
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 assessed using RQs from terrestrial plant seedling emergence and
vegetative vigor EC25 data as a screen. Since no acceptable data are available with which
to quantitatively assess the potential effects of iprodione on terrestrial plants and given
the weight-of-evidence available through open literature showing effects of iprodione to
terrestrial plants, risk is presumed. As such iprodione may indirectly affect the CRLF via
reduction in terrestrial plants.
5.1.3 Primary Constituent Elements of Designated Critical Habitat
For iprodione use, the assessment endpoints for designated critical habitat PCEs involve a
reduction and/or modification of food sources necessary for normal growth and viability
of aquatic-phase CRLFs, and/or a reduction and/or modification of food sources for
terrestrial-phase juveniles and adults. Because these endpoints are also being assessed
relative to the potential for indirect effects to aquatic- and terrestrial-phase CRLF, the
effects determinations for indirect effects from the potential loss of food items are used as
the basis of the effects determination for potential modification to designated critical
habitat.
5.1.3.1 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.
106
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• Reduction and/or modification of aquatic-based food sources for pre-metamorphs
(e.g., algae).
Based on the risk estimation for potential effects to aquatic and/or terrestrial plants
provided above (see Table 33), iprodione use has the potential to cause effects to aquatic
plants. No acceptable data are available with which to quantitatively assess the potential
effects of iprodione on terrestrial plants, which serve as surrogates for riparian
vegetation; however, the weight-of-evidence provide through open literature studies
suggests that iprodione exposure at label rates can result in adverse effects on terrestrial
plants. Therefore, risk to riparian vegetation is presumed. Therefore, iprodione may
affect aquatic-phase PCEs of designated habitat related to vegetation.
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
the impact of iprodione on this PCE (i.e., alteration of food sources), 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 are provided in
section 5.1.1. Based on LOG exceedances for the majority of iprodione uses for aquatic-
phase CRLF, aquatic invertebrates, algae or fish, iprodione may affect aquatic-phase
PCEs of designated habitat related to effects of alteration of other chemical
characteristics necessary for normal growth and viability of CRLFs and their food source.
5.1.3.2 Terrestrial-Phase (Upland Habitat and Dispersal Habitat)
The first two 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
each other that allow for movement between sites including both natural and
altered sites which do not contain barriers to dispersal
The risk estimation for terrestrial-phase PCEs of designated habitat related to potential
effects on terrestrial plants is provided above. Since no acceptable data are available with
which to quantitatively assess the potential effects of iprodione on terrestrial plants but
given the weight-of-evidence provided through open literature studies, risk is presumed.
As such, iprodione may result in modification of the terrestrial habitat of the CRLF.
The third terrestrial-phase PCE is "reduction and/or modification of food sources for
terrestrial phase juveniles and adults." To assess the impact of iprodione on this PCE,
acute and chronic toxicity endpoints for birds, mammals, and terrestrial invertebrates are
used as measures of effects. RQs for these endpoints are provided above. Because RQs
107
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exceed LOCs for all uses of iprodione for at least one prey item of the terrestrial-phase
CRLF, all uses of iprodione may result in modification of the terrestrial habitat of the
CRLF.
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. Direct acute and chronic RQs for terrestrial-phase CRLFs are presented above.
Because RQs exceed LOCs for all uses of iprodione for the CRLF or at least one prey
item of the terrestrial-phase CRLF, all uses of iprodione may result in modification of the
terrestrial habitat of the CRLF.
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.
Based on the RQs presented in the Risk Estimation (Section 5.1) a preliminary
effects determination for all uses of iprodione is "may affect" for the CRLF and
critical habitat. The direct or indirect effect LOCs are exceeded and these 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 iprodione. A
summary of the results of the risk estimation results are provided in Table 37 for direct
and indirect effects to the CRLF and in Table 38 for the PCEs of designated critical
habitat for the CRLF.
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Table 37. Risk Estimation Summary for Iprodione- Direct and Indirect Effects to CRLF.
Assessment Endpoint
LOC
Exceedances
(Y/N)
Description of Results of Risk Estimation
Aquatic-phase CRLF (eggs, larvae, tadpoles, juveniles, and adults)
Direct Effects
Survival, growth, and reproduction of
CRLF individuals via direct effects on
aquatic phases
Yes
Acute and chronic RQ values (based on iprodione
residues of concern) exceed the LOCs for the
majority of iprodione uses.
Indirect Effects
Survival, growth, and reproduction of
CRLF individuals via effects to food
supply (i.e., freshwater invertebrates,
non-vascular plants)
Yes
RQs for non-vascular plants and acute and chronic
RQs for aquatic invertebrates exceed the LOCs for
the majority of iprodione uses.
Indirect Effects
Survival, growth, and reproduction of
CRLF individuals via effects on habitat,
cover, and/or primary productivity (i.e.,
aquatic plant community)
Yes
The risk to aquatic nonvascular plant LOC is
exceeded for the majority of iprodione 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.
Yes
There is uncertainty regarding the chemical's
potential effect on terrestrial plants that provide
[riparian] cover for aquatic environment;
therefore, risk is presumed.
Terrestrial-phase CRLF (Juveniles and adults)
Direct Effects
Survival, growth, and reproduction of
CRLF individuals via direct effects on
terrestrial phase adults and juveniles
Yes
Acute dose-based and dietary-based RQ values
exceed the acute risk to listed species LOC; dose-
based RQ values exceed the acute risk to listed
species LOC by factors as high as 213X. Dietary-
based chronic RQ values exceed the chronic risk
LOC by factors as high as 39X.
Indirect Effects
Survival, growth, and reproduction of
CRLF individuals via effects on prey
(i.e., terrestrial invertebrates, small
terrestrial mammals and terrestrial
phase amphibians)
Yes
Acute risk to terrestrial invertebrates could
potentially exceed the level of concern for uses of
iprodione on ornamental plants and turf. Acute
dose-based RQ values and chronic RQ values
exceed the acute and chronic risk LOCs for small
mammals serving as prey. Acute and chronic RQ
values exceed the acute and chronic risk LOCs for
terrestrial-phase amphibians serving as prey for
terrestrial-phase CRLF.
Indirect Effects
Survival, growth, and reproduction of
CRLF individuals via effects on habitat
(i.e., riparian vegetation)
Yes
There is uncertainty regarding the chemical's
potential effect on terrestrial plants that provide
[riparian] cover for aquatic environment;
therefore, risk is presumed. Additionally, there are
incident reports involving terrestrial plants where
registered uses of iprodione resulted in damage to
plants
109
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Table 38. Risk Estimation Summary for Iprodione- PCEs of Designated Critical Habitat for the
CRLF.
Assessment Endpoint
LOG
Exceedances
(Y/N)
Description of Results of Risk
Estimation
Aquatic-phase CRLF 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.
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.
Alteration of other chemical characteristics necessary
for normal growth and viability of CRLFs and their
food source.
Reduction and/or modification of aquatic-based food
sources for pre-metamorphs (e.g., algae)
Yes
Yes
Yes
Yes
There is uncertainty regarding the
chemical's potential effect on terrestrial
plants that provide [riparian] cover for
aquatic environment; therefore, risk is
presumed.
There is uncertainty regarding the
chemical's potential effect on terrestrial
plants that provide [riparian] cover for
aquatic environment; therefore, risk is
presumed.
RQs for non-vascular plants and acute and
chronic RQs for CRLF, aquatic
invertebrates and fish exceed the LOCs for
the majority of iprodione uses.
RQs for aquatic non-vascular plants
exceed the LOG for the majority of
iprodione uses.
Terrestrial-phase CRLF 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
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
Yes
Yes
Yes
Yes
There is uncertainty regarding the
chemical's potential effect on terrestrial
plants that provide [riparian] cover for
aquatic environment; therefore, risk is
presumed.
There is uncertainty regarding the
chemical's potential effect on terrestrial
plants that provide [riparian] cover for
aquatic environment; therefore, risk is
presumed.
Acute risk to terrestrial invertebrates could
potentially exceed the level of concern for
uses of iprodione on ornamental plants and
turf. Acute dose-based RQ values and
chronic RQ values exceed the acute and
chronic risk LOCs for small mammals
serving as prey. Acute and chronic RQ
values exceed the acute and chronic risk
LOCs for terrestrial-phase amphibians
serving as prey for terrestrial-phase CRLF.
Acute risk to terrestrial invertebrates could
110
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Assessment Endpoint
normal growth and viability of juvenile and adult
CRLFs and their food source.
LOG
Exceedances
(Y/N)
Description of Results of Risk
Estimation
potentially exceed the level of concern for
uses of iprodione on ornamental plants and
turf. Acute dose-based RQ values and
chronic RQ values exceed the acute and
chronic risk LOCs for small mammals
serving as prey. Acute and chronic RQ
values exceed the acute and chronic risk
LOCs for terrestrial-phase amphibians
serving as prey for terrestrial-phase CRLF.
Following a "may affect" determination, additional information is considered to refine
the potential for exposure at the predicted levels based on the life history characteristics
(i.e.., habitat range, feeding preferences, etc.) of the CRLF. Based on the best available
information, the Agency uses the refined evaluation to distinguish those actions that
"may affect, but are not likely to adversely affect" from those actions that are "likely to
adversely affect" the CRLF and its designated critical habitat.
The criteria used to make determinations that the effects of an action are "not likely to
adversely affect" the CRLF and its designated critical habitat include the following:
• Significance of Effect: Insignificant effects are those that cannot be meaningfully
measured, detected, or evaluated in the context of a level of effect where "take"
occurs for even a single individual. "Take" in this context means to harass or
harm, defined as the following:
• Harm includes significant habitat modification or degradation that
results in death or injury to listed species by significantly impairing
behavioral patterns such as breeding, feeding, or sheltering.
• Harass is defined as actions that create the likelihood of injury to listed
species to such an extent as to significantly disrupt normal behavior
patterns which include, but are not limited to, breeding, feeding, or
sheltering.
• Likelihood of the Effect Occurring: Discountable effects are those that are
extremely unlikely to occur.
• Adverse Nature of Effect: Effects that are wholly beneficial without any adverse
effects are not considered adverse.
A description of the risk and effects determination for each of the established assessment
endpoints for the CRLF and its designated critical habitat is provided in Sections 5.2.1
through 5.2.3.
Ill
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5.2.1 Direct Effects
5.2.1.1 Aquatic-Phase CRLF
The aquatic-phase considers life stages of the frog that are obligatory aquatic organisms,
including eggs and larvae. It also considers submerged terrestrial-phase juveniles and
adults, which spend a portion of their time in water bodies that may receive runoff and
spray drift containing iprodione.
As described in Section 5.1.1.1 and Table 30, acute RQs for aquatic-phase CRLF are
sufficient to exceed the LOG (0.05) for all iprodione uses that are applied via ground
spray, chemigation or air spray. Chronic RQs for aquatic-phase CRLF are sufficient to
exceed the LOG (1.0) for the majority of iprodione uses that are applied via ground spray,
chemigation or air spray, with the exception of almonds, beans, peanuts, stone fruit and
strawberries. Acute and chronic RQs for uses that are applied via soil in-furrow treatment
(i.e.., cotton and garlic) and seed treatments do not exceed LOCs.
For use patterns that allow both aerial and ground spray applications according to the
label, aerial applications were modeled since they have higher spray drift fractions and
therefore higher EECs. For both ground and aerial applications the label requires a 25-ft
buffer between application sites and waterbodies. The AgDRIFT model was used to
predict the spray drift 25 ft from the application site following aerial and ground
applications. AgDRIFT predicts 9.3% and 2.3% spray drift for aerial and ground spray
applications, respectively. In order to gauge the impact that the lower spray drift value
resulting from a ground spray application has on the EECs, the almond scenario was
modeled both ways. Limiting the applications to ground spray would reduce the peak
EEC from 171 to 78 |ig/L, a reduction of greater than 50%. This suggests that mitigating
the labels to only allow ground applications could result in reducing EECs for some uses
to fall below LOCs for direct effects to the CRLF.
Available toxicity data for iprodione indicate that channel catfish are the most sensitive
species tested, with a 96-hr LCso of 3100 |ig/L; however, toxicity testing with bluegill
sunfish (Lepomis macrochirus) and rainbow trout (Oncorhynchus mykiss) resulted in 96-
hr LC50 values of 3,700 (Sousa 1990a) and 4,100 |ig/L (Sousa 1990*), respectively,
indicating that acute toxicity estimates for technical grade iprodione are relatively
consistent across the species tested. Although the dose response curve for channel catfish
did not provide a probit slope estimate, probit dose response slopes are available for
bluegill (slope = 11.8) and rainbow trout (slope = 8.2); the mean of the two slope
estimates is 10 (standard error: ±1.8). This average slope is used (in IEC vl.l) to
estimate the likelihood of individual mortality from acute exposures of aquatic-phase
CRLF to iprodione residues of concern (Table 39). For uses that result in RQs that are
close to the LOG, such as almonds (RQ = 0.06), the chance of individual mortality to an
aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high uses of iprodione on
ornamentals (26 applications per year), the chance of individual mortality to an aquatic-
phase CRLF is approximately 1 in 1.
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Table 39. Individual effects (mortality) chance analysis for acute exposures of
aquatic-phase CRLF to iprodione residues of concern.
Use(s)
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower, kale (seed treatment)
Berries2
Canola (foliar)
Canola (seed treatment)
Carrot (foliar)
Carrot (seed treatment)
Cole Crops3 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit4
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial lawns) (fall)
Turf (golf course, sod farm, commercial industrial lawns) (spring)
Turnip greens (foliar)
Turnip greens (seed treatment)
Acute RQ
0.061
0.071
0.01
0.101
0.261
0.01
0.151
0.01
0.381
0.101
0.01
0.02
0.101
0.02
0.211
0.231
0.091
0.511
16.81
0.081
2.481
0.071
0.091
0.121
0.01
O.ll1
O.01
0.071
0.061
0.441
0.271
0.491
0.291
0.361
0.01
Chance of
individual
mortality
(~1 in...)
8.21E+35
5.7E+29
1.8E+119
2.9E+22
3.4E+08
4.3E+76
4.0E+16
1.3E+114
7.4E+04
2.0E+22
3.0E+143
3.2E+65
4.1E+22
1.1E+72
1.1E+11
6.4E+09
7.6E+25
6.1E+02
l.OE+00
3.1E+27
l.OE+00
1.2E+31
1.1E+25
2.8E+20
1.8E+115
9.3E+20
1.1E+218
1.5E+30
1.5E+34
4.6E+03
2.0E+08
9.3E+02
2.4E+07
2.1E+05
4.2E+99
1 Exceeds acute risk LOC of 0.05.
2 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
3 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
113
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There is considerable uncertainty in this assessment in the approach of modeling total
residues of concern. In this assessment, it is assumed that iprodione, 3,5-DCA
(iprodione's terminal degradate) and all major iprodione degradates containing the 3,5-
DCA moiety are of concern. As noted previously, a limited amount of data are available
to characterize the toxicity of 3,5-DCA to non-target organisms. No data are available to
characterize the toxicities of iprodione's major degradates that contain the 3,5-DCA
moiety. Therefore, it is assumed in this assessment that all of iprodione's residues of
concern are equivalent in toxicity to iprodione. In order to explore effects of this
uncertainty on risk conclusions, EECs were derived using PRZM/EXAMS for iprodione
(only) based on ground spray, chemigation and aerial spray applications only. All input
parameters were the same as those described in section 3.1, with the exception of the
chemical-specific parameters that are defined in Table 40. EECs are provided in Table
41. If RQs were developed using EECs for high use on ornamentals (26 applications per
year), they would be sufficient to exceed acute and chronic risk LOCs for the aquatic-
phase CRLF.
Table 40. PRZM/EXAMS input parameters relevant to the fate of iprodione (only).
Input Parameter
Molecular Wt. (g/mol)
Henry's Law Constant (atm-
m3/mol)
Vapor pressure (torr)
Solubility in water
(mg/L @ pH 7, 20°C)
Hydrolysis half-life (days)
Aqueous photolysis (days)
Aerobic Soil Metabolism Half -life
(days)
Aerobic Aquatic Metabolism Half-
life (days)
Anaerobic Aquatic Metabolism
Half-life (days)
Koc
Value
330.2
9.0xlO'9
2.7xlO'7
13
4.7
67
300
0
0
426
Comments
See Table 5
See Table 5
See Table 5
See Table 5
Based on value for neutral water (pH 7) (See
Table 6)
See Table 6
For iprodione, half life was estimated
(deviating from Input Parameter Guidance,
as guidance does not cover this situation)
from 2 studies — one in which the half -life
was >100 and one in which the half life was
300 days (See Table 6)
Studies provided were dominated by
hydrolysis, so assumed stable to aerobic
metabolism
Studies provided were dominated by
hydrolysis, so assumed stable
Mean of Koc values for iprodione (Table 8).
Inputs determined in accordance with EFED "Guidance for Chemistry and Management Practice Input
Parameters for Use in Modeling the Environmental Fate and Transport of Pesticides" dated February 28,
2002
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Table 41. Aquatic EECs generated using PRZM/EXAMS for iprodione (only).
Use(s)
Almonds
Beans
Berries1
Canola
Carrots
Cole Crops2 and Crucifer
conifers
Grapes
Grapes
Lettuce (air ap)
Lettuce (ground ap)
Onion
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanut
Potato
Radish
Rutabaga
Stone furits (apricot, cherry, nectarine, peach, plum,
prune)
Strawberry
turf (golf course - greens, tees and aprons) (fall)
turf (golf course - greens, tees and aprons) (spring)
turf (golf course, sod farm, commercial industrial
lawns) (fall)
turf (golf course, sod farm, commercial industrial
lawns) (spring)
turnip greens
Peak EEC
(Hg/L)
6.2
12.3
7.5
39.6
16.9
48.4
25.3
9.3
14.5
32.8
33.1
5.1
142.8
3560
17.7
416.9
10.3
8.0
9.6
9.0
11.1
14.7
72.9
21.9
85.4
18.0
44.9
21-d EEC
(Mg/L)
3.2
5.4
3.6
16.2
8.8
20.1
9.3
5.1
7.1
12.8
12.3
2.7
50.8
1118
6.3
133.9
3.3
4.0
5.4
5.3
5.3
6.1
26.4
10.2
30.4
8.8
18.3
60-d EEC
(Mg/L)
1.8
2.6
2.6
8.2
4.2
10.5
4.9
2.9
3.5
6.0
5.5
2.1
20.3
474.6
2.6
52.4
1.9
2.6
3.4
3.1
2.6
2.7
10.5
5.5
12.1
5.0
8.6
USGS NAWQA monitoring data collected in California indicate detections as high as
141 |ig/L, which are on the same order of magnitude as the highest EECs generated for
iprodione (i.e.., those for use on ornamentals). This measured value exceeds peak
iprodione (only) EECs generated for the majority of iprodione uses. If an acute RQ were
developed using the highest detection of iprodione in surface water, this value would be
0.046.
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In order to bound EECs relevant to 3,5-DCA, uses with the minimum and maximum peak
EECs derived for iprodione residues of concern (i.e., cotton and 26 drench applications to
ornamentals, respectively) were modeled. Use specific parameters include application
methods and rates. Application methods, maximum rates per application and maximum
number of applications per year are based on current label directions for use of iprodione
on cotton and drench applications to ornamentals (Table 20). The application rate is
converted to a 3,5-DCA equivalent using the molecular weight of 3,5-DCA. In this
approach, available laboratory fate studies indicate that 3,5-DCA is the terminal
degradate and that this degradate is stable; as such, it is assumed that 100% of iprodione
is converted to 3,5-DCA at the time of application. Therefore, the maximum single
application rate for cotton is equivalent to 0.147 kg of 3,5-DCA/ha (0.131 Ibs a.i./A). The
maximum single application rate for drench applications to ornamentals is 12.3 kg of 3,5-
DCA/ha (11.0 Ibs a.i./A).The input parameters relevant to the fate of 3,5-DCA used in
PRZM and EXAMS are in Table 42. Aquatic EECs derived for 3,5-DCA based on uses
of iprodione on cotton and ornamentals (26 drench applications) are provided in Table
43
Table 42. PRZM/EXAMS input parameters relevant to the fate of 3,5-DCA.
Input Parameter
Molecular Wt. (g/mol)
Henry's Law Constant (atm-
m3/mol)
Vapor pressure (torr)
Solubility in water
(mg/L @ pH 7, 20°C)
Hydrolysis half-life (days)
Aqueous photolysis (days)
Aerobic Soil Metabolism Half -life
(days)
Aerobic Aquatic Metabolism Half-
life (days)
Anaerobic Aquatic Metabolism
Half-life (days)
Koc (L/kgoc)
Value
162.02
5.8 xlO'6
2.12xlO'2
784
0
0
0
0
0
610
Comments
See Table 5
See Table 5
See Table 5
See Table 5
Assume stable
Assume stable
Assume stable
Assume stable
Assume stable
Mean of Koc values for 3,5-DCA (Table 9).
116
-------
Table 43. Aquatic EECs (jig/L) for 3,5-DCA based on iprodione Uses in California.
Crops Represented
Cotton
Ornamentals (drench - 26 applications)
Peak EECs
2.15
2216
21-day average EECs
1.60
1825
60-day average EECs
1.06
1364
As discussed previously, the toxicity of 3,5-DCA to fish (surrogates for aquatic-phase
amphibians) is less than that of the parent compound. If RQ values were derived using
aquatic EECs generated for 3,5-DCA in combination with available fish toxicity data for
3,5-DCA (guppy LC50=3900 ug/L; zebrafish NOAEC = 1000 ug/L), acute and chronic
RQs would be below their respective LOCs (0.05 and 1.0) for iprodione use on cotton
and above the LOCs for the maximum iprodione use scenario of 26 drench applications
to ornamentals.
Monitoring efforts in California have detected 3,5-DCA; however, it is uncertain whether
these detections are associated with the use of iprodione. The maximum level of 3,5-
DCA detected in surface water is 0.027 ug/L, a value that is several orders of magnitude
lower than EECs provided in Table 43.
As discussed previously, iprodione use on golf courses has been associated with an
ecological incident resulting in the death of an unspecified number of freshwater fish
following a runoff event. This incident suggests that the application of iprodione to golf
courses can result in aquatic exposures sufficient to cause mortality of aquatic vertebrates
such as fish and amphibians. It should be noted that this incident occurred in 1992 and
before the RED (USEPA 1998) indicating that the uses may have been associated with
labels that were modified as a result of the RED.
Based on this information, there is potential for direct effects to the aquatic-phase CRLF
from all iprodione uses that are applied via ground spray, chemigation or aerial spray.
Effects are not expected from uses that are applied via soil in-furrow treatment (i.e.,
cotton and garlic) and seed treatments.
5.2.1.2 Terrestrial-Phase CRLF
Acute exposures
As discussed in Section 5.1.2.1, acute dose-based RQ values generated using T-REX for
small birds feeding on small insects exceed the acute risk to listed species LOG by factors
ranging from 2.3x to 143x across all of the uses evaluated except for use on cotton.
In order to explore influences of amphibian-specific food intake equations on potential
acute dose-based and chronic dietary-based exposures of the terrestrial-phase CRLF to
iprodione, T-HERPS was used. An example output from T-HERPS is provided in
Appendix L.
117
-------
Refined acute, dietary-based RQs were not calculated because iprodione was classified as
practically non-toxic to birds on a subacute dietary basis. EECs generated using T-REX
for the terrestrial-phase CRLF are below the highest test level of the subacute studies
with birds (i.e.., 5,620 mg/kg), with the exception of the high (i.e., 26) application
scenario for drench applications to ornamentals. This indicates that all uses of iprodione,
with the exception of 4 drench applications to ornamentals, are not expected to pose a
risk to terrestrial-phase CRLF through acute, dietary-based exposures.
Refined dose-based RQs for small sized (1.4 g) CRLF consuming insects do not exceed
the acute listed species LOG (0.1) for all uses of iprodione, with the exception of the
drench use on ornamentals (Table 44). In this case, only RQs representing the small
CRLF consuming only small insects are sufficient to exceed the LOG, while the RQ for
small CRLFs consuming large insects does not exceed the acute LOG. The acute, dose-
based RQ for the small, terrestrial-phase CRLF exposed to iprodione from drench
applications to ornamentals is between 0.01 and 0.52. This translates to a chance of
individual effects ranging 1 in 10 to 1 in 8.9xl018 (derived using IECvl.1 and assuming a
default slope of 4.5).
Refined dose-based RQs for medium sized (37 g) CRLF exceed the acute listed species
LOG (0.1) for at least one food item for all uses of iprodione, with the exception use on
cotton (Table 45). Acute, dose-based RQs are highest for medium CRLF consuming
small herbivore mammals, with a range of 0.16 to 14.9 for all uses, excluding cotton.
This translates to a chance of individual effects ranging 1 in Ito 1 in 5853 (derived using
IECvl.1 and assuming a default slope of 4.5). For medium CRLF consuming small
insectivore mammals, RQs for ornamentals and for turf exceed the LOG, with values
ranging 0.14 to 0.93. This translates to a chance of individual effects ranging 1 in 2 to 1
in 16,400. For medium CRLF consuming small insects, RQs for ornamentals exceed the
LOG, with values ranging 0.12 to 0.51. This translates to a chance of individual effects
ranging 1 in 11 to 1 in 58,500. Acute, dose-based RQs for the medium terrestrial-phase
CRLF consuming large insects and small, terrestrial-phase amphibians do not exceed the
LOG.
Refined dose-based RQs for large-sized (238 g) CRLF exceed the acute listed species
LOG (0.1) for at least one food item for iprodione use on canola, cole crops, conifers,
crucifer, ornamentals, rutabagas, turf and turnip greens (Table 46). Acute, dose-based
RQs are highest for medium CRLF consuming small herbivore mammals, with a range of
0.10 to 2.32 for uses where the LOG is exceeded. This translates to a chance of
individual effects ranging 1 in 1 to 1 in 294,000 (derived using IECvl.1 and assuming a
default slope of 4.5). For medium CRLF consuming small insectivore mammals and
small insects, the only use where RQs exceed the LOG is drench applications to
ornamentals, with RQs of 0.14 and 0.34, respectively. This translates to a chance of
individual effects ranging 1 in 57 to 1 in 16,400. Acute, dose-based RQs for the large
terrestrial-phase CRLF consuming large insects and small, terrestrial-phase amphibians
do not exceed the LOG.
118
-------
The most sensitive endpoint is an acute oral toxicity study with Northern bobwhite quail
where the LD50 is 930 mg/kg bw (McGinnis 1973); however, in a more recent registrant-
submitted study with Northern bobwhite quail, the acute oral LDso value exceeded the
highest concentration tested, i.e., 2000 mg/kg bw, and where no mortality was observed
in any of the treatment groups (Culotta et al. 1990). The more recent acute oral toxicity
study by Culotta et al. (1990) is more consistent with the available subacute dietary
toxicity studies indicating that iprodione is practically nontoxic to birds on a subacute
dietary exposure basis. The subacute dietary toxicity studies for Northern bobwhite quail
(Driscoll et al. 1990a) and for mallard ducks {Anas platyrhyncos; Driscoll et al. 1990&)
both resulted in LCso values greater than the highest concentration tested, i.e., 5,620
mg/kg diet. In the quail study, 2 birds were dead in the 5,620 mg/kg diet group while in
the mallard study none of the birds died.
Table 44. Revised dose-based RQs1 for 1.4 g CRLF consuming different food items. EECs calculated
using T-HERPS.
Use
Almonds
Beans
Berries2
Canola
Carrots
Cole Crops 3
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone Fruit4
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Small insects
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.01
0.02
0.01
0.02
0.01
0.02
0.01
0.52s
0.13s
0.09
0.02
0.01
0.02
0.02
0.02
0.01
0.01
0.08
0.08
0.02
Large insects
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.06
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Based on dose-based EEC and iprodione Northern bobwhite quail acute oral LD50 = 930 mg/kg-bw
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5 RQ > acute risk to endangered species LOG of 0.1.
119
-------
Table 45. Revised dose-based RQs1 for 37 g CRLF consuming different food items. EECs calculated
using T-HERPS.
Use
Almonds
Beans
Berries2
Canola
Carrots
Cole Crops 3
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone Fruit4
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Small
insects
0.01
0.01
0.02
0.02
0.02
0.02
0.02
0.01
0.02
0.01
0.02
0.01
0.02
0.01
0.51s
0.12s
0.09
0.02
0.01
0.02
0.02
0.02
0.01
0.01
0.08
0.08
0.02
Large
insects
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.06
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Small
herbivore
mammals
0.26s
0.31s
0.45s
0.62s
0.53s
0.62s
0.66s
0.04
0.62s
0.32s
0.53s
0.40s
0.49s
0.37s
14.9s
3.61s
2.50s
0.45s
0.38s
0.49s
0.56s
0.62s
0.41s
0.16s
2.42s
2.31s
0.62s
Small
insectivore
mammals
0.02
0.02
0.03
0.04
0.03
0.04
0.04
0.01
0.04
0.02
0.03
0.03
0.03
0.02
0.93s
0.23s
0.16s
0.03
0.02
0.03
0.04
0.04
0.03
0.01
0.15s
0.14s
0.04
Small
terrestrial-
phase
amphibians
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Based on dose-based EEC and iprodione Northern bobwhite quail acute oral LD50 = 930 mg/kg-bw
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5 RQ > acute risk to endangered species LOG of 0.1.
120
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Table 46. Revised dose-based RQs1 for 238 g CRLF consuming different food items. EECs calculated
using T-HERPS.
Use
Almonds
Beans
Berries2
Canola
Carrots
Cole Crops 3
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone Fruit4
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Small
insects
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.34s
0.08
0.06
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.05
0.05
0.01
Large
insects
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.04
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Small
herbivore
mammals
0.04
0.05
0.07
0.10s
0.08
0.10s
0.10s
0.01
0.10s
0.05
0.08
0.06
0.08
0.06
2.32s
0.56s
0.39s
0.07
0.06
0.08
0.09
0.10s
0.06
0.03
0.38s
0.36s
0.10s
Small
insectivore
mammals
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.14s
0.04
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.02
0.02
0.01
Small
terrestrial-
phase
amphibians
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Based on dose-based EEC and iprodione Northern bobwhite quail acute oral LD50 = 930 mg/kg-bw
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5 RQ > acute risk to endangered species LOG of 0.1.
121
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Table 47. Revised acute dietary-based RQs1 for CRLF consuming different food items. EECs
calculated using T-HERPS.
Use
Almonds
Beans
Berries2
Canola
Carrots
Cole Crops 3
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone Fruit4
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Small
insects
0.04
0.05
0.07
0.09
0.08
0.09
0.10
0.01
0.09
0.05
0.08
0.06
0.07
0.06
<2.225
0.54
O.37
0.07
0.06
0.07
0.08
0.09
0.06
0.02
0.36
0.34
0.09
Large
insects
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.25
0.06
0.04
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.04
0.04
0.01
Small
herbivore
mammals
0.05
0.05
0.09
0.11
0.09
0.11
0.12
0.01
0.11
0.06
0.09
0.07
0.09
0.07
<2.61 5
0.63
0.44
0.08
0.07
0.09
0.10
0.11
0.07
0.03
0.42
0.40
0.11
Small
insectivore
mammals
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.16
0.04
0.03
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.03
0.03
0.01
Small
terrestrial-
phase
amphibians
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.08
0.02
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
0.01
Based on dose-based EEC and iprodione Northern bobwhite quail subacute dietary LC50 >5,620 mg/kg-
2Specifically:blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5EEC exceeds highest test limit of sub-acute dietary study with Northern bobwhite quail (where no mortality was observed)
122
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Chronic exposures
Preliminary chronic (dietary-based) RQ values generated using T-REX ranged from 1.05
to 48.8 across 19 of the 24 use categories evaluated. Revised chronic RQs for at least one
prey item generated using T-HERPS exceed the LOG (1.0) for every use of iprodione,
except almonds, beans, cotton and strawberries (Table 48). RQs are highest for CRLF
consuming small herbivore mammals, with RQs that exceed the LOG ranging 1.13 to
48.8. RQs for CRLF consuming small insects exceed the LOG for the majority of
iprodione uses with the exception of almonds, beans, cotton, garlic, onions, peanuts and
strawberries, with RQs that exceed the LOG ranging 1.04 to 26.0. RQs for CRLF
consuming large insects, small insectivore mammals and small terrestrial-phase
amphibians exceed the LOG only for drench applications of iprodione to ornamentals.
It should be noted that the specific diet of the terrestrial-phase CRLF is unknown, and,
therefore, the proportion of the diet that can be attributed to small and large insects, small
herbivore mammals, small insectivore mammals and small terrestrial-phase amphibians is
unknown. In order to bound the exposure of the terrestrial-phase CRLF to iprodione,
separate RQs are developed for CRLF consuming 100% of each of its potential prey
items. Since the CRLF is an opportunistic feeder, it is more likely that the diet will be
composed of a mixture of these prey, with the specific proportion being dependant upon
the available prey. Therefore, the highest RQs, which correspond to chronic exposures of
the terrestrial-phase CRLF to iprodione through consumption of (100%) small herbivore
mammals are not necessarily representative of the risk of the CRLF to iprodione.
The NOAEC used to derive RQs for the terrestrial-phase CRLF is 300 mg/kg diet, which
is based on an avian reproduction study with Northern bobwhite quail (Fink et al.
198 la.), where statistically significant effects were observed at 1000 mg/kg-diet
(LOAEC) in the number of eggs laid (24% decline), hatchling body weight (26% decline)
and in the number of normal hatchlings out of eggs set (26% decline). RQs are based on
a level where no effects are observed in a reproduction test. There is uncertainty
associated with the level where effects can actually be expected, with that level falling
somewhere between the NOAEC and the LOAEC. If EECs generated using T-HERPS
are compared to the LOAEC (1,000 mg/kg-diet), the EECs for iprodione use on
ornamentals and turf are sufficient to exceed the LOAEC.
123
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Table 48. Revised chronic dietary-based RQsl for CRLF consuming different food items. EECs
calculated using T-HERPS.
Use
Almonds
Beans
Berries2
Canola
Carrots
Cole Crops 3
Conifers
Cotton
Crucifer
Garlic
Grapes
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench high)
Ornamentals (drench low)
Ornamentals (foliar high)
Ornamentals (foliar low)
Peanuts
Potatoes
Radishes
Rutabagas
Stone Fruit4
Strawberries
Turf (sod)
Turf (tees)
Turnip greens
Small
insects
0.69
0.80
1.16s
1.62s
1.38s
1.62s
1.72s
0.11
1.62s
0.83
1.38s
1.04s
1.27s
0.98
41.7s
9.40s
6.98s
1.17s
0.98
1.27s
1.46s
1.62s
1.08s
0.42
6.27s
5.98s
1.62s
Large
insects
0.07
0.09
0.13
0.18
0.15
0.18
0.19
0.01
0.18
0.09
0.15
0.11
0.14
0.11
4.63s
1.04s
0.78
0.13
0.11
0.14
0.16
0.18
0.12
0.05
0.69
0.67
0.18
Small
herbivore
mammals
0.81
0.93
1.36s
1.89s
1.61s
1.89s
2.01s
0.13
1.89s
0.98
1.61s
1.22s
1.50s
1.13s
48.8s
11.0s
8.18s
.38s
.14s
.50s
.71s
.89s
.25s
0.49
7.36s
7.00s
1.89s
Small
insectivore
mammals
0.05
0.06
0.08
0.12
0.10
0.12
0.13
0.01
0.12
0.06
0.10
0.07
0.09
0.07
3.05s
0.69
0.51
0.08
0.07
0.09
0.11
0.12
0.07
0.03
0.46
0.44
0.12
Small
terrestrial-
phase
amphibians
0.03
0.03
0.04
0.06
0.05
0.06
0.06
<0.01
0.06
0.03
0.05
0.04
0.05
0.04
1.45s
0.32
0.24
0.04
0.04
0.05
0.05
0.06
0.04
0.02
0.22
0.20
0.06
Based on dietary-based EEC and iprodione Northern bobwhite quail NOAEC = 300 mg/kg-diet.
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
5RQ> chronic risk LOC of 1.0
Spatial extent of risks to terrestrial-phase CRLF (due to spray drift transport)
EECs and relevant RQs (Table 44-Table 48) calculated by T-HERPS apply to sites
where iprodione is directly applied. Since iprodione can be transported through spray
drift to non-target areas beyond the treatment site, CLRFs outside of direct treatment
areas can still be exposed to iprodione in non-target areas. Exposure and associated risks
to the CRLF are expected to decrease with increasing distance away from the treated field
or site of application.
Based on acute effects data, spray drift deposition of iprodione from a single application
as low as 0.62 Ibs a.i./A (calculated using T-HERPS) would be sufficient to exceed at
least one LOC for the CRLF. For all uses of iprodione, this distance is estimated to
extend <37 feet from the edge of the application site (Table 49).
124
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Table 49. Distance from edge of field where spray drift transport from single aerial application rate
does not exceed LOCs for exposures of the CRLF to iprodione.
Use(s)
almonds
onions
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
peanuts, potatoes, radishes,
strawberries, turnip greens
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
peanuts, potatoes, radishes,
strawberries, turnip greens
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
potatoes, radishes, strawberries, turnip
greens
Conifers
Conifers
Stone fruits3
Stone fruits3
Stone fruits3
Ornamentals
Turf
Application
method(s)
Ground,
airblast and
aerial spray
ground and
aerial spray
ground spray
airblast
air spray
ground spray
Airblast
(sparse trees)
ground spray
ground spray
air spray
ground spray
ground spray
Max single
application
rate
(Ibs a.i./A)
0.5
0.75
1
1
1
1.25
1.25
1.3725
1.3725
1.3725
2.805
8.16
Distance from edge of
field (ft) where LOCs
are not exceeded1
0
0
o
J
0
0
7
0
7
0
3
13
36
For a single application
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
'Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifically: apricots, cherries, nectarines, peaches, plums, prunes
Summary of effects of iprodione on terrestrial-phase CRLF
Based on LOG exceedances for refined acute and chronic RQs for the terrestrial-phase
CRLF, all uses of iprodione, except cotton, are likely to adversely affect the CRLF.
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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. As discussed in Section
5.1.1.2 and as summarized in Table 31, RQs for non-vascular plants are sufficient to
exceed the LOG (1.0) for all iprodione uses that are applied via ground spray,
chemigation or air spray. The RQ for soil in-furrow treatment of garlic also exceeds the
LOG. RQs for soil in-furrow treatment to cotton and all seed treatments are below the
LOG.
Toxicity data for other aquatic plants include studies on the estuarine/marine diatom (S.
costatum 120-hr ECso=330 |ig/L; Giddings 1990a), green algae (P. subcapitata 120-hr
EC50= 1,800 ng/L; Giddings 1990J) and cyanobacteria (A. flos-aquae 120-hr EC50>860
Hg/L; Giddings 1990e). Compared to the most sensitive toxicity estimate for aquatic
plants, i.e., N. pelliculosa ECso= 50 |ig/L, the other nonvascular aquatic plants tested are
relatively insensitive.
As noted in section 5.2.1.1., there is considerable uncertainty in this assessment in the
approach of modeling total residues of concern. If RQs were developed using EECs for
iprodione only (Table 41), they would be sufficient to exceed the aquatic plant LOG for
iprodione use on ornamentals and turf.
Although there are limited toxicity data available for the 3,5-DCA degradate, the
compound appears to be less toxic to non-target species than the parent compound.
Available toxicity data for 3,5-DCA in green algae indicate an ECso of 7500 |ig/L which
is four times less toxic than the estimate for green algae (ECso =1800 ug/L) tested with
the parent compound.
To the extent that 3,5-DCA is less toxic and depending on the extent to which iprodione
degrades to 3,5-DCA, the RQ values estimating potential risk to aquatic plants based on
the toxicity of the parent compound and estimates of total toxic residues would be highly
conservative. However, based on total residues and the most sensitive toxicity estimate
for the parent compound, i.e., 50 |ig/L, RQ values exceed the LOG by factors ranging
from 1.2 to 154X.
5.2.2.2 Aquatic Invertebrates
The potential for iprodione to elicit indirect effects to the CRLF via effects on freshwater
invertebrate food items is dependent on several factors including: (1) the potential
magnitude of effect on freshwater invertebrate individuals and populations; and (2) the
number of prey species potentially affected relative to the expected number of species
needed to maintain the dietary needs of the CRLF. Together, these data provide a basis
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to evaluate whether the number of individuals within a prey species is likely to be
reduced such that it may indirectly affect the CRLF.
As discussed in section 5.1.1.2, acute RQs for aquatic invertebrates exceed the LOG for
all uses of iprodione, except cotton (in-furrow) and seed treatments to rutabagas and
turnip greens. Chronic RQs exceed the LOG for all uses of iprodione, except cotton (in-
furrow) and seed treatments of broccoli, Brussels sprouts, cabbage, cauliflower, kale,
carrots, kohlrabi, radishes, rutabagas and turnip greens. Except for use on cotton, all RQs
for uses where iprodione is applied via ground spray, chemigation or aerial spray are
sufficient to exceed acute and chronic LOCs (Table 32).
With an acute 48-hr EC50 of 240 |ig/L (McNamara 1990), iprodione is classified as
highly toxic to freshwater invertebrates on an acute exposure basis. Two additional
studies of D. magna are available, one by Roberts (1977) reported a 48-hr static LCso of
382 |ig/L. The second study by Vilkas (1977) reports a 48-hr LC50 of 7200 |ig/L for D.
magna. Although the studies by McNamara (1990) and Roberts (1977) have relatively
consistent toxicity estimates for D. magna, the study by Vilkas is an order of magnitude
less sensitive.
Although not reported in the original study nor in the EPA data evaluation record for the
study by McNamara, the probit dose-response slope associated with the 48-hr ECso is
3.45. This slope is used (in IEC vl.l) to estimate the probability of effects from acute
exposures of aquatic invertebrates to iprodione residues of concern (Table 50). For uses
that result in RQs that are close to the LOG, such as seed treatments to broccoli, Brussels
sprouts, cabbage, cauliflower and kale (RQ = 0.06), the probability of effects to aquatic
invertebrates is low (chance of <0.01%). For high uses of iprodione on ornamentals (26
applications per year), the probability of effects to aquatic invertebrates is approximately
100%
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Table 50. Probability of mortality to aquatic invertebrates resulting from acute exposures to
iprodione.
Use(s)
Almonds
Beans
Broccoli, Brussels sprouts, cabbage, cauliflower, kale (seed
treatment)
Berries2
Canola (foliar)
Canola (seed treatment)
Carrot (foliar)
Carrot (seed treatment)
Cole Crops3 and crucifer
Conifers
Cotton
Garlic
Grapes
Kohlrabi (seed treatment)
Lettuce (aerial)
Lettuce (ground)
Onions
Ornamentals (drench - 1 application)
Ornamentals (drench - 26 applications)
Ornamentals (foliar- 1 application)
Ornamentals (foliar-26 applications)
Peanuts
Potatoes
Radishes (foliar)
Radishes (seed treatment)
Rutabagas (foliar)
Rutabagas (seed treatment)
Stone Fruit4
Strawberries
Turf (golf course - greens, tees and aprons) (fall)
Turf (golf course - greens, tees and aprons) (spring)
Turf (golf course, sod farm, commercial industrial lawns) (fall)
Turf (golf course, sod farm, commercial industrial lawns) (spring)
Turnip greens (foliar)
Turnip greens (seed treatment)
Invertebrate
Acute RQ
0.711
0.931
0.061
1.341
3.381
0.181
1.871
0.071
4.911
1.351
0.04
0.251
1.331
0.201
2.751
3.031
1.121
6.561
2171
1.041
32.01
0.881
1.171
1.491
0.071
1.451
0.01
0.911
0.771
5.751
3.451
6.371
3.761
4.661
0.101
Probability
30.51%
45.83%
0.01%
66.85%
96.61%
0.50%
82.64%
<0.01%
99.15%
67.34%
0.01%
1.86%
66.40%
0.87%
93.52%
95.18%
56.85%
99.76%
100.00%
52.18%
100.00%
42.29%
59.34%
72.57%
0.00%
71.11%
0.01%
44.68%
34.47%
99.56%
96.84%
99.72%
97.65%
98.94%
0.02%
1 Exceeds acute risk LOC of 0.05.
2 Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
3 Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4 Specifically: apricots, cherries, nectarines, peaches, plums, prunes
As noted in section 5.2.1.1., there is considerable uncertainty in this assessment in the
approach of modeling total residues of concern. If RQs were developed using EECs for
iprodione only (Table 41), they would be sufficient to exceed the acute LOC for several
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uses of iprodione, including beans, canola carrots, cole crops, crucifer, conifers, grapes,
lettuce, ornamentals, strawberries, turf, and turnip greens (applications via ground spray,
chemigation or aerial spray). If chronic RQs were developed, they would be sufficient to
exceed the LOG for iprodione use on ornamentals.
Available toxicity data indicate that 3,5-DCA is less toxic to aquatic animals than the
parent compound. For waterfleas, 3,5-DCA (ECso =1120 ug/L; Maas-Diepeveen and van
Leeuwen 1986) is 5 times less toxic than the parent compound (48-hr EC50=240 ug/L). If
RQ values were derived using aquatic EECs generated for 3,5-DCA (Table 43) in
combination with available acute toxicity data for 3,5-DCA the acute RQ for cotton
would be below the LOG (0.05), while the acute RQ for 26 drench applications to
ornamentals would be above the LOG.
To the extent that 3,5-DCA is less toxic and depending on the extent to which iprodione
degrades to 3,5-DCA, the RQ values estimating potential risk to aquatic invertebrates
based on the toxicity of the parent compound and estimates of total toxic residues would
be highly conservative. However, based on total residues and the most sensitive toxicity
estimate for the parent compound, i.e., 240 ug/L, RQ values exceed the LOG by factors
ranging from 1 to 4,340X.
5.2.2.3 Fish and Aquatic-phase Frogs
As discussed in Section 5.2.1.1 (indirect effects to fish and frogs as food items are based
on the direct effects analysis for aquatic-phase CRLFs), acute RQs for fish are sufficient
to exceed the LOG (0.05) for all iprodione uses that are applied via ground spray,
chemigation or air spray. Chronic RQs for fish are sufficient to exceed the LOG (1.0)
for the majority of iprodione uses that are applied via ground spray, chemigation or air
spray, with the exception of almonds, beans, peanuts, stone fruit and strawberries. Acute
and chronic RQs for uses that are applied via soil in-furrow treatment (i.e., cotton and
garlic) and seed treatments do not exceed LOCs.
Section 5.2.1.1 explores the likelihood of individual mortality to aquatic-phase CRLF
exposed to total residues of iprodione as well as uncertainties associated with considering
total residues of concern vs. only iprodione. The contents of section 5.2.1.1 also apply to
characterization of indirect effects to aquatic-phase CRLF through effects to fish and
aquatic-phase frogs that represent the prey of the CRLF. Therefore, based on the
conclusions of section 5.2.1.1, there is potential for effects to fish and aquatic-phase
amphibians from all iprodione uses that are applied via ground spray, chemigation or
aerial spray. Effects are not expected from uses that are applied via soil in-furrow
treatment (i.e., cotton and garlic) and seed treatments.
5.2.2.4 Terrestrial Invertebrates
When the terrestrial-phase CRLF reaches juvenile and adult stages, its diet is mainly
composed of terrestrial invertebrates. Iprodione is practically nontoxic to honeybees on
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an acute contact exposure basis. Since the honeybee acute contact LD50 value for
iprodione is higher than the highest dosage tested, i.e., LD50>120 jig/bee, all of the RQ
values are less than the calculated value. For all but two of the uses evaluated, i.e.,
drench applications to ornamental plants and applications to turf, the EECs were less than
the NOAEC value for bees (NOAEC=120 |ig/bee) in the acute contact toxicity study, and
mortality is not considered likely at these exposure levels. However, there is uncertainty
regarding the potential effect on bees at the higher EECs for ornamental plants and turf.
Additionally, there is an incident report for honeybees indicating that iprodione exposure
may result in deleterious effects on bee brood development. Honeybee larval and pupal
development and survival were impaired by exposure of larvae to 0.5 jig/bee. If RQs
were based on a toxicity value of 0.5 jig/bee and T-REX-estimated exposure
concentrations, all of the RQ values would exceed the acute risk LOG. In a recent study
by vanEnglesdorp et al. 2009, iprodione has been measured in wax samples collected
from bee colonies; mean iprodione residue levels in wax were 48.9±21|ig/kg. In
unpublished data, Pennsylvania State University researchers have analyzed wax from 208
samples collected from commercial bee colonies; 6.7% of the wax samples contained
iprodione residues with maximum iprodione residues of 636 |ig/kg (personal
communication: Dr. Chris Mullin, Department of Entomology, Pennsylvania State
University, September 2, 2009). These data indicate that iprodione is detected in
honeybee colonies where it can potentially affect brood development. It is presumed that
the residues of iprodione detected in bee colonies are a result of registered uses of the
fungicide. Given the uncertainty regarding the effects of iprodione on terrestrial
invertebrates and the likely exposure, potential risk to terrestrial invertebrates cannot be
precluded.
5.2.2.5 Mammals
Life history data for terrestrial-phase CRLFs indicate that large adult frogs consume
terrestrial vertebrates, including mice. As discussed in Section 5.1.2.2.2 and summarized
in Table 36, acute and chronic RQ values exceed acute and chronic LOCs. For all of the
uses evaluated, chronic dose-based chronic RQ values exceed the chronic risk LOG by
factors as high as 521X. The chronic, dietary-based RQ for mammals consuming
iprodione-treated seeds is 278. Except for use on cotton, dietary-based RQ values exceed
the chronic risk LOG by factors as high as 74X.
EECs and relevant RQs calculated by T-REX apply to sites where iprodione is directly
applied. Since iprodione can be transported through spray drift to non-target areas beyond
the treatment site, Small mammals (prey of CRLF) outside of direct treatment areas can
still be exposed to iprodione in non-target areas. Exposure and associated risks to the
small mammals are expected to decrease with increasing distance away from the treated
field or site of application.
Based on acute and chronic effects data, spray drift deposition of iprodione from a single
application as low as 0.17 Ibs a.i./A (calculated using T-REX) would be sufficient to
exceed at least one LOG for small mammals consuming short grass. For all uses of
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iprodione, this distance is estimated to extend <122 feet from the edge of the application
site (Table 51)
Table 51. Distance from edge of field where spray drift transport from single aerial application rate
does not exceed LOCs for exposures of the small mammals (consuming sort grass) to iprodione.
Use(s)
almonds
almonds
onions
onions
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
peanuts, potatoes, radishes,
strawberries, turnip greens
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
peanuts, potatoes, radishes,
strawberries, turnip greens
Beans, berries1, canola, carrots, cole
crops2, crucifer, grapes, lettuce,
potatoes, radishes, strawberries, turnip
greens
Conifers
Conifers
Stone fruits3
Stone fruits3
Stone fruits3
Ornamentals
Turf
Application
method(s)
ground and
aerial spray
airblast
ground spray
aerial spray
ground spray
airblast
air spray
Ground spray
Airblast
(sparse trees)
ground spray
airblast
air spray
Ground spray
Ground spray
Max single
application
rate
(Ibs a.i./A)
0.5
0.5
0.75
0.75
1
1
1
1.25
1.25
1.3725
1.3725
1.3725
2.805
8.16
Distance from edge of
field (ft) where LOCs
are not exceeded1
10
0
13
26
16
0
52
20
20
23
0
79
43
121
For a single application
2Specifically: blackberries, blueberries, caneberries, currants, elderberries, gooseberries, huckleberries, loganberries, raspberries
3Specifically: broccoli, Brussels sprouts, cabbage, cauliflower, kale, kohlrabi
4Specifially: apricots, cherries, nectarines, peaches, plums, prunes
Based on the acute and chronic risks posed by iprodione to mammals serving as prey,
iprodione is considered likely to indirectly affect the CRLF for all uses.
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5.2.2.6 Terrestrial-phase Amphibians
Terrestrial-phase adult CRLFs also consume frogs. RQ values representing direct
exposures of iprodione to terrestrial-phase CRLFs are used to represent exposures of
iprodione to frogs in terrestrial habitats. As discussed in Section 5.2.1.2 (indirect effects
to frogs as food items are based on the direct effects analysis for terrestrial-phase CRLF)
RQ values exceed the acute risk LOG by factors of 2.3 - 143X across all of the uses
evaluated except for cotton. Chronic RQ values exceed the chronic risk LOG by factors
ranging from 1.05 to 28X across 19 of the 24 uses evaluated. Based on the acute and
chronic risks posed by iprodione to terrestrial-phase amphibians serving as prey,
iprodione is considered likely to indirectly affect the CRLF.
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 as attachment sites and refugia for
many aquatic invertebrates, fish, and juvenile organisms, such as fish and frogs. In
addition, vascular plants also provide primary productivity and oxygen to the aquatic
ecosystem. Rooted 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. Based on the available data for vascular plants, iprodione is likely to affect
vascular aquatic plants for uses other than cole crops, canola, carrots, cotton, Kohlrabi
(seed treatment), rutabagas and turnip greens (seed treatment). Of the uses evaluated for
nonvascular plants, all uses except cole, canola, carrots, cotton, kohlrabi (seed treatment),
radishes, rutabagas and turnip greens the application of iprodione to ornamental plants
exceeded the LOG. Based on the number of exceedances, iprodione could indirectly
adversely affect the CRLF through reduction in vascular and nonvascular aquatic plants.
5.2.3.2 Terrestrial Plants
Terrestrial plants serve several important habitat-related functions for the CRLF. In
addition to providing habitat and cover for invertebrate and vertebrate prey items of the
CRLF, terrestrial vegetation also provides shelter for the CRLF and cover from predators
while foraging. Terrestrial plants also provide energy to the terrestrial ecosystem through
primary production. 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,
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nutrients, and contaminants before they reach the watershed, and serving as an energy
source.
Due to a lack of effects data for terrestrial plants exposed to iprodione, there is
uncertainty regarding the chemical's potential effect on terrestrial plants that provide
cover for terrestrial environment; therefore, risk is presumed. To further bolster concerns
for potential adverse effects on terrestrial plants, there are ecological incidents reported in
the EIIS indicating terrestrial plant damage following the application of iprodione. As a
result, there is potential for indirect effects to the CRLF due to effects to plants in its
terrestrial habitat.
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:
• 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).
Conclusions for potential indirect effects to the CRLF via direct effects to aquatic and
terrestrial plants are used to determine whether modification to critical habitat may occur.
At some of the higher application rates assessed, iprodione use could result in the loss of
nonvascular aquatic plants. Additionally, there is uncertainty regarding the potential for
iprodione to affect terrestrial plants; however, there are at least 14 incident reports in the
EIIS indicating that terrestrial plants can be damaged by direct exposure to iprodione. As
such, there is a potential for habitat modification via impacts to aquatic plants (Sections
5.2.2.1 and 5.2.3.1) and terrestrial plants (5.2.3.2).
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 is 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. Impacts to
aquatic invertebrates, fish and aquatic-phase amphibians (Section 5.2.2.2) are considered
likely and as a result indirectly impact the CRLF through reduction in available prey.
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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
each other that allow for movement between sites including both natural and
altered sites which do not contain barriers to dispersal.
As stated previously, there is uncertainty regarding the potential for iprodione to affect
terrestrial plants; however, there are at least 14 incident reports in the EIIS indicating that
terrestrial plants can be damaged by direct exposure to iprodione. As such, there is a
potential for habitat modification via impacts to terrestrial plants (Section 5.2.3.2).
The third terrestrial-phase PCE is "reduction and/or modification of food sources for
terrestrial phase juveniles and adults." To assess the impact of iprodione on this PCE,
acute and chronic toxicity endpoints for terrestrial invertebrates, mammals, and
terrestrial-phase frogs are used as measures of effects. Given the uncertainty regarding
potential effects on terrestrial invertebrates and given the likely effects of iprodione on
mammals and terrestrial-phase amphibians that serve as prey for CRLF, there is a
potential for habitat modification via indirect effects to terrestrial-phase CRLFs via
reduction in prey base (Section 5.2.2.4 for terrestrial invertebrates, Section 5.2.2.5 for
mammals, and 5.2.2.6 for frogs).
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 described in Section 5.2.1.2, terrestrial-phase CRLF are considered likely to
be directly adversely affected by chronic exposure to iprodione. Additionally, as
discussed in Section 5.2.2.4, there is uncertainty regarding the potential effects of
iprodione on the development and survival of terrestrial invertebrates following chronic
exposure to the fungicides and risk to these prey items is considered possible. Iprodione
is also considered likely to result in both acute and chronic effects on small mammals
(Section 5.2.2.5), fish and aquatic-phase amphibians (Section 5.2.2.6) that serve as prey
for the CRLF and as a result indirect effects to terrestrial-phase CRLFs are considered
likely.
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5.2.5 Addressing the Risk Hypotheses
In order to conclude this risk assessment, it is necessary to address the risk hypotheses
defined in section 2.9.1. Based on the conclusions of this assessment, none of the
hypotheses can be rejected, meaning that the stated hypotheses represent concerns in
terms of direct and indirect effects of iprodione on the CRLF and its designated critical
habitat.
6.0 Uncertainties
6.1 Exposure Assessment Uncertainties
6.1.1 Environmental Fate Data
Submitted iprodione degradation studies involving soils are characterized by high levels
of unextracted and unidentified residues which lead to uncertain degradation
characterizations. For example, in a submitted aerobic soil degradation study, 75 to 87%
of the residues were unextracted and uncharacterized after 300 days. Thus, it remains
unknown if and how much of these residues are parent iprodione or degradates of
concern. It is also unclear as to the extent to which they may be bound into the soil
matrix. Nevertheless, terrestrial and aquatic field dissipation studies tend to imply that
iprodione dissipates in the environment with a DT50 of 3 to 7 days. However, because of
the extraction concerns raised in the soil studies, it is unknown whether these DT50 values
represent true degradation or simply a temporary sequestering of iprodione (or degradates
of concern) that can be released over time. In the case that 3,5-DCA may covalently bond
to organic matter, this binding can result in tight adsorption to soil and reduce its
likelihood to leave the treatment site. However, given that 3,5-DCA has been detected in
surface and ground water samples collected by the USGS NAWQA program, some 3,5-
DCA is still unbound and available to reach water.
6.1.2 Maximum Use Scenario
The screening-level risk assessment focuses on characterizing potential ecological risks
resulting from a maximum use scenario, which is determined from labeled statements of
maximum application rate and number of applications with the shortest time interval
between applications. The frequency at which actual uses approach this maximum use
scenario may be dependant on pest resistance, timing of applications, cultural practices,
and market forces.
In the case of the ornamental use, the maximum number of applications that may be made
in 1 year is not specified on the label. In order to bound the EECs that may result for this
use, a minimum application per year of 1 was modeled as well as a maximum of 26 per
year (based on the minimum application interval of 14 d for drench and the limit of 26
applications per year in the pe5 shell for foliar applications).
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6.1.3 Aquatic Exposure Modeling of Iprodione
The standard ecological water body scenario (EXAMS pond) used to calculate potential
aquatic exposure to pesticides is intended to represent conservative estimates, and to
avoid underestimations of the actual exposure. The standard scenario consists of
application to a 10-hectare field bordering a 1-hectare, 2-meter deep (20,000 m3) pond
with no outlet. Exposure estimates generated using the EXAMS pond are intended to
represent a wide variety of vulnerable water bodies that occur at the top of watersheds
including prairie pot holes, playa lakes, wetlands, vernal pools, man-made and natural
ponds, and intermittent and lower order streams. As a group, there are factors that make
these water bodies more or less vulnerable than the EXAMS pond. Static water bodies
that have larger ratios of pesticide-treated drainage area to water body volume would be
expected to have higher peak EECs than the EXAMS pond. These water bodies will be
either smaller in size or have larger drainage areas. Smaller water bodies have limited
storage capacity and thus may overflow and carry pesticide in the discharge, whereas the
EXAMS pond has no discharge. As watershed size increases beyond 10-hectares, it
becomes increasingly unlikely that the entire watershed is planted with a single crop that
is all treated simultaneously with the pesticide. Headwater streams can also have peak
concentrations higher than the EXAMS pond, but they likely persist for only short
periods of time and are then carried and dissipated downstream.
The Agency acknowledges that there are some unique aquatic habitats that are not
accurately captured by this modeling scenario and modeling results may, therefore,
under- or over-estimate exposure, depending on a number of variables. For example,
aquatic-phase CRLFs may inhabit water bodies of different size and depth and/or are
located adjacent to larger or smaller drainage areas than the EXAMS pond. The Agency
does not currently have sufficient information regarding the hydrology of these aquatic
habitats to develop a specific alternate scenario for the CRLF. CRLFs prefer habitat with
perennial (present year-round) or near-perennial water and do not frequently inhabit
vernal (temporary) pools because conditions in these habitats are generally not suitable
(Hayes and Jennings 1988). Therefore, the EXAMS pond is assumed to be representative
of exposure to aquatic-phase CRLFs. In addition, the Services agree that the existing
EXAMS pond represents the best currently available approach for estimating aquatic
exposure to pesticides (USFWS/NMFS 2004).
In general, the linked PRZM/EXAMS model produces estimated aquatic concentrations
that are expected to be exceeded once within a ten-year period. The Pesticide Root Zone
Model is a process or "simulation" model that calculates what happens to a pesticide in
an agricultural field on a day-to-day basis. It considers factors such as rainfall and plant
transpiration of water, as well as how and when the pesticide is applied. It has two major
components: hydrology and chemical transport. Water movement is simulated by the use
of generalized soil parameters, including field capacity, wilting point, and saturation
water content. The chemical transport component can simulate pesticide application on
the soil or on the plant foliage. Dissolved, adsorbed, and vapor-phase concentrations in
the soil are estimated by simultaneously considering the processes of pesticide uptake by
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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
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.
6.1.4 Potential Ground water Contributions to Surface Water Chemical
Concentrations
Although the potential impact of discharging ground water on CRLF populations is not
explicitly delineated, it should be noted that ground water could provide a source of
pesticide to surface water bodies - especially low-order streams, headwaters, and ground
water-fed pools. This is particularly likely if the chemical is persistent and mobile.
Soluble chemicals that are primarily degrade by photolysis will be very likely to persist in
ground water, and can be transportable over long distances. Similarly, many chemicals
degrade slowly under anaerobic conditions (common in aquifers) and are thus more
persistent in ground water. Much of this ground water will eventually be discharged to
the surface - often supporting stream flow in the absence of rainfall. Continuously
flowing low-order streams in particular are sustained by ground water discharge, which
can constitute 100% of stream flow during baseflow (no runoff) conditions. Thus, it is
important to keep in mind that pesticides in ground water may have a major (detrimental)
impact on surface water quality, and on CRLF habitats.
SciGrow was used in this assessment to determine likely 'high-end' ground water
vulnerability, with the assumption (based upon persistence in sub- and anoxic conditions,
and mobility) that much of the compound entering the ground water will be transported
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some distance and eventually discharged into surface water. Although concentrations in
a receiving water body resulting from ground water discharge cannot be explicitly
quantified, it should be assumed that significant attenuation and retardation of the
chemical will have occurred prior to discharge. Nevertheless, ground water could still be
a significant consistent source of chronic background concentrations in surface water, and
may also add to surface runoff during storm events (as a result of enhanced ground water
discharge typically characterized by the 'tailing limb' of a storm hydrograph).
As noted in section 3.1.9, 3,5-DCA has been detected in ground water samples collected
in CA. The maximum detected concentration of 3,5-DCA was 0.0983 |ig/L (USGS
2009). This indicates that iprodione's degradate of concern has the potential to reach
ground water.
6.1.5 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 usage data, there may
be instances of misuse and misreporting. The Agency made use of the most current,
verifiable information; in cases where there were discrepancies, the most conservative
information was used.
6.1.6 Terrestrial Exposure Modeling of Iprodione
The Agency relies on the work of Fletcher et al. (1994) for setting the assumed pesticide
residues in wildlife dietary items. These residue assumptions are believed to reflect a
realistic upper-bound residue estimate, although the degree to which this assumption
reflects a specific percentile estimate is difficult to quantify. It is important to note that
the field measurement efforts used to develop the Fletcher estimates of exposure involve
highly varied sampling techniques. It is entirely possible that much of these data reflect
residues averaged over entire above ground plants in the case of grass and forage
sampling.
It was assumed that ingestion of food items in the field occurs at rates commensurate
with those in the laboratory. Although the screening assessment process adjusts dry-
weight estimates of food intake to reflect the increased mass in fresh-weight wildlife food
intake estimates, it does not allow for gross energy differences. Direct comparison of a
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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 the terrestrial exposure analysis of this risk assessment, a generic bird or mammal
was assumed to occupy either the treated field or adjacent areas receiving a treatment rate
on the field. Actual habitat requirements of any particular terrestrial species were not
considered, and it was assumed that species occupy, exclusively and permanently, the
modeled treatment area. Spray drift model predictions suggest that this assumption leads
to an overestimation of exposure to species that do not occupy the treated field
exclusively and permanently.
Given that no suitable data on interception and subsequent dissipation from foliar
surfaces is available for iprodione residues of concern, the EFED default foliar
dissipation half-life of 35 days is used based on the work of Willis and McDowell (1987).
This represents an uncertainty in the terrestrial exposure assessment in that the actual
dissipation of iprodione residues of concern from the terrestrial environment is unknown.
The use of the 35-d value is assumed to be conservative.
6.1.7 Spray Drift Modeling
Although there may be multiple iprodione applications at a single site, it is unlikely that
the same organism would be exposed to the maximum amount of spray drift from every
application made. In order for an organism to receive the maximum concentration of
iprodione from multiple applications, each application of iprodione would have to occur
under identical atmospheric conditions (e.g.., same wind speed and - for plants - same
wind direction) and (if it is an animal) the animal being exposed would have to be present
directly downwind at the same distance after each application. Although there may be
sites where the dominant wind direction is fairly consistent (at least during the relatively
quiescent conditions that are most favorable for aerial spray applications), it is
nevertheless highly unlikely that plants in any specific area would receive the maximum
amount of spray drift repeatedly. It appears that in most areas (based upon available
meteorological data) wind direction is temporally very changeable, even within the same
day. Additionally, other factors, including variations in topography, cover, and
meteorological conditions over the transport distance are not accounted for by the
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AgDRIFT model (i.e., it models spray drift from aerial and ground applications in a flat
area with little to no ground cover and a steady, constant wind speed and direction).
Therefore, in most cases, the drift estimates from AgDRIFT may overestimate exposure
even from single applications, especially as the distance increases from the site of
application, since the model does not account for potential obstructions (e.g., large hills,
berms, buildings, trees, etc.). Furthermore, conservative assumptions are made regarding
the droplet size distributions being modeled ('ASAE Very Fine' for agricultural uses), the
application method (e.g., aerial), release heights and wind speeds. Alterations in any of
these inputs would change the area of potential effect.
6.2 Effects Assessment Uncertainties
6.2.1 Age Class and Sensitivity of Effects Thresholds
It is generally recognized that test organism age may have a significant impact on the
observed sensitivity to a toxicant. The acute toxicity data for fish are collected on
juvenile fish between 0.1 and 5 grams. Aquatic invertebrate acute testing is performed on
recommended immature age classes (e.g., first instar for daphnids, second instar for
amphipods, stoneflies, mayflies, and third instar for midges).
Testing of juveniles may overestimate toxicity at older age classes for pesticide active
ingredients that act directly without metabolic transformation because younger age
classes may not have the enzymatic systems associated with detoxifying xenobiotics. In
so far as the available toxicity data may provide ranges of sensitivity information with
respect to age class, this assessment uses the most sensitive life-stage information as
measures of effect for surrogate aquatic animals, and is therefore, considered as
protective of the CRLF.
6.2.2 Use of Surrogate Species Effects Data
Guideline toxicity tests and open literature data on iprodione are not available for frogs or
any other aquatic-phase amphibian; therefore, freshwater fish are used as surrogate
species for aquatic-phase amphibians. Therefore, endpoints based on freshwater fish
ecotoxicity data are assumed to be protective of potential direct effects to aquatic-phase
amphibians including the CRLF, and extrapolation of the risk conclusions from the most
sensitive tested species to the aquatic-phase CRLF is likely to overestimate the potential
risks to those species. Efforts are made to select the organisms most likely to be affected
by the type of compound and usage pattern; however, there is an inherent uncertainty in
extrapolating across phyla. In addition, the Agency's LOCs are intentionally set very
low, and conservative estimates are made in the screening level risk assessment to
account for these uncertainties.
6.2.3 Sublethal Effects
When assessing acute risk, the screening risk assessment relies on the acute mortality
endpoint as well as a suite of sublethal responses to the pesticide, as determined by the
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testing of species response to chronic exposure conditions and subsequent chronic risk
assessment. Consideration of additional sublethal data in the effects determination t 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. However, the full suite of sublethal effects from valid
open literature studies is considered for the purposes of defining the action area.
Iprodione has been demonstrated to affect steroidogenesis, and more specifically,
inhibition of testosterone synthesis in testicular Leydig cells. As such the chemical is
capable of acting on endocrine-mediated processes. Available data for iprodione indicate
that it affects reproductive endpoints across a range of taxa. Since the terminal degradate
of iprodione, i.e, 3,5-DCA, is classified as a "likely" carcinogen (USEPA 19986) and
may act through a different mode of action than the parent compound, there are a number
of sublethal effects that could be associated with iprodione This assessment has
attempted to account for sublethal effects by setting the initial area of concern as the
entire State of California. To the extent to which sublethal effects are not considered in
this assessment, the potential direct and indirect effects of iprodione on CRLF may be
underestimated.
6.2.4 Location of Wildlife Species
For the terrestrial exposure analysis of this risk assessment, a generic bird or mammal
was assumed to occupy either the treated field or adjacent areas receiving a treatment rate
on the field. Actual habitat requirements of any particular terrestrial species were not
considered, and it was assumed that species occupy, exclusively and permanently, the
modeled treatment area. Spray drift model predictions suggest that this assumption leads
to an overestimation of exposure to species that do not occupy the treated field
exclusively and permanently.
7.0 Risk Conclusions
In fulfilling its obligations under Section 7(a)(2) of the Endangered Species Act, the
information presented in this endangered species risk assessment represents the best data
currently available to assess the potential risks of iprodione to the CRLF and its
designated critical habitat.
Based on the best available information, the Agency makes a Likely to Adversely Affect
determination for the CRLF from the use of iprodione. The Agency has determined that
there is the potential for modification of CRLF designated critical habitat from the use of
the chemical. All of the uses of iprodione might affect the frog and its critical habitat.
Although the higher application rates modeled for drench applications to ornamental
plants exceed the acute risk LOG for direct effects to CRLF, the likelihood of individual
mortality is less than 1 in a million and as such, the potential for adverse effects is
considered discountable. However, based on chronic RQ values that exceed the LOG,
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chronic effects of iprodione on reproduction could directly adversely affect the terrestrial-
phase CRLF. Effects on aquatic nonvascular plants and aquatic invertebrates that serve
as the forage base for aquatic-phase CRLF are also likely to be adversely affected and in
turn affect the CRLF. Effects on terrestrial-phase amphibians, mammals, terrestrial
insect that serve as forage for terrestrial-phase CRLF are likely to indirectly adversely
affect the CRLF. Additionally, there is uncertainty regarding the effects of iprodione on
terrestrial plants; however, there are incident data indicating terrestrial plant damage from
registered uses of iprodione. With the uncertainty regarding the toxicity of iprodione to
terrestrial plants and the incident data, risk is presumed to terrestrial plants and it is
determined that iprodione uses in California are assumed likely to indirectly adversely
affect the CRLF through reduced riparian cover. Given the LAA determination for the
CRLF and potential modification of designated critical habitat, a description of the
baseline status and cumulative effects for the CRLF is provided in Attachment II.
The LAA effects determination applies to those areas where it is expected that the
pesticide's use will directly or indirectly affect the CRLF or its designated critical habitat.
To determine this area, the footprint of iprodione's use pattern is identified, using land
cover data that correspond to iprodi one's use pattern. The spatial extent of the LAA
effects determination also includes areas beyond the initial area of concern that may be
impacted by runoff and/or spray drift. The identified direct and indirect effects and
modification to critical habitat are anticipated to occur only for those currently occupied
core habitat areas, CNDDB occurrence sections, and designated critical habitat for the
CRLF that overlap with the initial area of concern plus 121 feet from its boundary, based
on a single application of iprodione. It is assumed that non-flowing waterbodies (or
potential CRLF habitat) are included within this area.
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 Table 52
and Table 53
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Table 52. Effects Determination Summary for Iprodione Use and the CRLF.
Assessment
Endpoint
Effects
Determination
Basis for Determination
Survival, growth,
and/or
reproduction of
CRLF
individuals
Potential for Direct Effects
Likely to
adversely affect
(LAA) for all
uses
Aquatic-phase (Eggs, Larvae, and Adults):
Acute RQs based on iprodione residues of concern for aquatic-phase CRLF are
sufficient to exceed the LOG (0.05) for all iprodione uses that are applied via
ground spray, chemigation or air spray. For uses that result in RQs that are close
to the LOG, such as almonds (RQ = 0.06), the chance of individual mortality to an
aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high uses of iprodione
on ornamentals (26 applications per year), the chance of individual mortality to an
aquatic-phase CRLF is approximately 1 in 1.
Chronic RQs for aquatic-phase CRLF are sufficient to exceed the LOG (1.0) for the
majority of iprodione uses that are applied via ground spray, chemigation or air
spray, with the exception of almonds, beans, peanuts, stone fruit and strawberries.
Acute and chronic RQs for uses that are applied via soil in-furrow treatment (i.e.,
cotton and garlic) and seed treatments do not exceed LOCs.
If RQs were developed using EECs for iprodione only and for 3,5-DCA only, for
high use on ornamentals (26 applications per year), they would be sufficient to
exceed acute and chronic LOCs for the aquatic-phase CRLF.
there is an incident report involving a fish kill associated with the use of iprodione
on golf course turf.
Terrestrial-phase (Juveniles and Adults):
Preliminary acute RQs (generated using T-REX) exceed the level of concern for all
uses of iprodione, except cotton. Refined acute, dose-based RQs (generated using
T-HERPS) for the small CRLF consuming small insects exceed the LOG for
drench applications of iprodione on ornamentals. The likelihood of individual
mortality to small CRLF exposed to iprodione from drench applications ranges 1 in
10 to 1 in 8.9xl018. Refined acute, dose-based RQs for the medium CRLF
consuming small herbivore mammals exceed the LOG for all uses of iprodione,
except cotton. The likelihood of individual mortality for the medium CRLF is as
high as 1 in 1. Refined acute, dose-based RQs for the large CRLF exceed the LOG
for iprodione use on canola, cole crops, conifers, crucifer, ornamentals, rutabagas,
turf and turnip greens. The likelihood of individual mortality for the large CRLF is
as high as 1 in 1.
Preliminary chronic (dietary-based) RQ values generated using T-REX ranged
from 1.04 to 38.6 across 19 of the 24 use categories evaluated. Revised chronic
RQs for at least one prey item generated using T-HERPS exceed the LOG (1.0) for
every use of iprodione, except almonds, cotton and strawberries. In addition, EECs
for iprodione use on ornamentals and turf are sufficient to exceed the LOAEC.
For all uses of iprodione, spray drift exposure is of concern <37 feet from the edge
of the application site.
Potential for Indirect Effects
Aquatic prey items, aquatic habitat, cover and/or primary productivity
RQs for non-vascular plants are sufficient to exceed the LOG (1.0) for all iprodione
uses that are applied via ground spray, chemigation or air spray. The RQ for soil
in-furrow treatment of garlic also exceeds the LOG. RQs for soil in-furrow
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Assessment
End point
Effects
Determination
Basis for Determination
treatment to cotton and all seed treatments are below the LOG.
All aquatic invertebrate RQs for uses where iprodione is applied via ground spray,
chemigation or aerial spray are sufficient to exceed acute and chronic LOCs
Acute RQs based on iprodione residues of concern for fish and aquatic-phase
amphibians are sufficient to exceed the LOG (0.05) for all iprodione uses that are
applied via ground spray, chemigation or air spray. For uses that result in RQs that
are close to the LOG, such as almonds (RQ = 0.06), the chance of individual
mortality to an aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high
uses of iprodione on ornamentals (26 applications per year), the chance of
individual mortality to an aquatic-phase CRLF is approximately 1 in 1. Chronic
RQs for fish and aquatic-phase amphibians are sufficient to exceed the LOG (1.0)
for the majority of iprodione uses that are applied via ground spray, chemigation or
air spray, with the exception of almonds, beans, peanuts, stone fruit and
strawberries. Acute and chronic RQs for uses that are applied via soil in-furrow
treatment (i.e., cotton and garlic) and seed treatments do not exceed LOCs.
Based on the above information, there is potential for indirect effects to the aquatic-
phase CRLF from use of iprodione.
Terrestrial prey items, riparian habitat
Acute risk to terrestrial invertebrates could potentially exceed the LOG for uses of
iprodione on ornamental plants and turf. Acute dose-based RQ values and chronic
RQ values exceed the acute and chronic risk LOCs for small mammals serving as
prey. Chronic RQ values exceed the chronic risk LOG for terrestrial-phase
amphibians serving as prey for terrestrial-phase CRLF. There is considerable
uncertainty regarding the effects of iprodione on terrestrial invertebrates and based
on incident data, risk is presumed.
There is uncertainty regarding the chemical's potential effect on terrestrial plants
that provide [riparian] cover for aquatic environment; therefore, risk is presumed.
Additionally, there are incident reports involving terrestrial plants where registered
uses of iprodione resulted in damage to plants.
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Table 53. Effects Determination Summary for Iprodione Use and CRLF Critical Habitat Impact
Analysis.
Assessment
Endpoint
Effects
Determination
Basis for Determination
Modification
of aquatic-
phase PCE
Habitat
Modification
Modification
of terrestrial-
phase PCE
There is uncertainty (due to a lack of effects data for plants) regarding the chemical's
potential effect on terrestrial plants that provide [riparian] cover for aquatic
environment; therefore, risk is presumed. Additionally, there are incident reports
involving terrestrial plants where registered uses of iprodione resulted in damage to
plants.
RQs for non-vascular plants that may serve as a forage base for aquatic-phase CRLF
are sufficient to exceed the LOG (1.0) for all iprodione uses that are applied via ground
spray, chemigation or air spray. The RQ for soil in-furrow treatment of garlic also
exceeds the LOG. RQs for soil in-furrow treatment to cotton and all seed treatments
are below the LOG.
All aquatic invertebrate RQs for uses where iprodione is applied via ground spray,
chemigation or aerial spray are sufficient to exceed acute and chronic LOCs
Acute RQs based on iprodione residues of concern for fish and aquatic-phase
amphibians are sufficient to exceed the LOG (0.05) for all iprodione uses that are
applied via ground spray, chemigation or air spray. For uses that result in RQs that
are close to the LOG, such as almonds (RQ = 0.06), the chance of individual mortality
to an aquatic-phase CRLF is low (chance of 1 in 8.21 xlO35). For high uses of
iprodione on ornamentals (26 applications per year), the chance of individual mortality
to an aquatic-phase CRLF is approximately 1 in 1. Chronic RQs for fish and aquatic-
phase amphibians are sufficient to exceed the LOG (1.0) for the majority of iprodione
uses that are applied via ground spray, chemigation or air spray, with the exception of
almonds, beans, peanuts, stone fruit and strawberries. Acute and chronic RQs for uses
that are applied via soil in-furrow treatment (i.e., cotton and garlic) and seed
treatments do not exceed LOCs.
There is uncertainty regarding the chemical's potential effect on terrestrial plants that
provide cover for the terrestrial environment; therefore, risk is presumed. Additionally,
there are incident reports involving terrestrial plants where registered uses of iprodione
resulted in damage to plants.
Acute risk to terrestrial invertebrates could potentially exceed the level of concern for
uses of iprodione on ornamental plants and turf. Additionally, there is uncertainty
regarding the potential effects of iprodione on larval terrestrial invertebrates and risk is
presumed based on an incident report. Acute dose-based RQ values and chronic RQ
values exceed the acute and chronic risk LOCs for small mammals serving as prey.
Chronic RQ values exceed the chronic risk LOG for terrestrial-phase amphibians
serving as prey for terrestrial-phase CRLF.
Dietary-based chronic RQ values exceed the chronic risk LOG for terrestrial-phase
amphibians by factors as high as 28X and as such, available mammalian prey items
may be reduced in CRLF habitat.
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Based on the conclusions of this assessment, a formal consultation with the U. S. Fish
and Wildlife Service under Section 7 of the Endangered Species Act should be initiated.
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 prey responses to pesticide exposure would allow for a more refined
determination of the magnitude and duration of resource impairment, and together
with the information described above, a more complete prediction of effects to
individual frogs and potential modification to critical habitat.
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8.0 References
Adrian, P.; Robles, J. (1991) Carbon 14-Iprodione: Aqueous Photolysis: Lab Project
Number: 90/22: AG/CBLD/AN/9115524. Unpublished study prepared by Rhone-
Poulenc Secteur Agro. 97 p. (MRID 418619-01)
Alvarez, J. 2000. Letter to the U.S. Fish and Wildlife Service providing comments on
the Draft California Red-legged Frog Recovery Plan.
American Bird Conservancy. 2009. Avian Incident Monitoring System (AIMS).
http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm
Atkins, E. et al. 1975. Effect of pesticides on agriculture. Project #149K. 1975 Annual
Report. Department of Entomology, University of California at Riverside.
Beketov, M. A. and M. Liess. 2008. Potential of 11 Pesticides to Initiate Downstream
Drift of Stream Macroinvertebrates. Archives of Environmental Contamination
and Toxicology. 55. p247-253.
Benson, D.M. 1991. Control of Rhizoctonia Stem Rot of Poinsettia During Propagation
with Fungicides that Prevent Colonization of Rooting Cubes by Rhizoctonia
solani. Plant Disease. 75 (4), 394-398.
Benson, D.M. 1992. Fungicides as Foliar Sprays or Rooting Cube Soaks in Propagation
of Poinsettia. HortScience 27 (9), 1006-1008.
Burr, C.; Newby, S. (1994) Iprodione: Adsorption/Desorption to and from Four Soils and
an Aquatic Sediment: Lab Project Number: P94/014. Unpublished study prepared
by Rhone-Poulenc Agriculture Ltd. 81 p. (MRID 433492-02).
Chambers, P. R., D. Crook, W. A. Gibson, C. Gopinath and S. A. Ames. 1992.
Iprodione Tumorigenic and Toxic Effects in Prolonged Dietary Administration.
Unpublished study prepared by Rhone-Poulenc Agrrochimie. (MRID 426378-01).
Chancey, E. (1995) An Aquatic Field Dissipation Study with Iprodione: Lab Project
Number: 44729: EC-92-187: FAD-IPR-RI-MS-92. Unpublished study prepared
by Rhone-Poulenc Ag Co.; Agvise, Inc.; and South Texas Ag Research Inc. 374
p. (MRID 437183-01).
Crawshaw, GJ. 2000. Diseases and Pathology of Amphibians and Reptiles in:
Ecotoxicology of Amphibians and Reptiles; ed: Sparling, D.W., G. Linder, and
C.A. Bishop. SETAC Publication Series, Columbia, MO.
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Culotta, I, K. A. Hoxter, G. J. Smith, and M. Jaber. 1990. Iprodione: An Acute Oral
Toxicity Study with the Northern Bobwhite. Study performed by Wildlife
International Ltd., Easton, Maryland. Laboratory Project #171-120. Submitted
by Rhone-Poulenc Ag Company, Research Triangle Park, NC (MRID 416041-
01).
Cummins, H. (1989) Iprodione: Acute Oral Toxicity Study in the Rat: Lab Project
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