# Risks of Endosulfan Use to the Federally Threatened

California Red-legged Frog ( Rana aurora draytonii )



# , 

# Bay Checkerspot Butterfly ( Euphydryas editha bayensis 

# ), 

# Valley Elderberry Longhorn Beetle ( Desmocerus californicus

dimorphus 

# ) 

# , and California Tiger Salamander ( Ambystoma californiense 

# )



# And the Federally Endangered
San Francisco Garter Snake ( Thamnophis sirtalis tetrataenia 

# ), 

# San Joaquin Kit Fox ( Vulpes macrotis mutica 

# ) 

# , and
Salt Marsh Harvest Mouse ( Reithrodontomys raviventris 

# )

Pesticide Effects Determinations

Environmental Fate and Effects Division Office of Pesticide Programs Washington, D.C. 20460

June 18, 2009

Primary Authors : Ecological Effects Keith Sappington, M.S ., Biologist, OPP/EFED Glen Thursby, Ph.D, Bi ologist, ORD/NHEERL/AED Sandy Raimondo, Ph.D., Ecologist, ORD/NHEERL/GED

Environmental Fate Mohammed Ruhman, Ph.D, Agronomist, OPP/EFED

Secondary Review : Mah Shamim, Ph.D., Branch Chief, OPP/EFED
Environmental Risk Assessment Branch 5

1

## Table of Contents

1 Executive Summary .............................................................................................11

2 Problem Formulation ..........................................................................................25 2.1 Purpose

............................................................................................................................... . 25 2.2 Scope................................................................................................................................... 27
2.3 Previous Assessments ......................................................................................................... 29
2.4 Stressor Source and Distribution ........................................................................................ 30 2.4.1 Environmental Fate Properties ..................................................................................... 32 2.4.2 Environmental Transport Mechanisms ........................................................................ 36
2.4.3 Mechanism of Action ................................................................................................... 36
2.4.4 Use Characterization.................................................................................................... 37 2.5 Assessed Species ................................................................................................................. 48 2.6 Designated Critical Habitat ................................................................................................. 53
2.7 Action Area ......................................................................................................................... 55 2.8 Assessment Endpoints and Measures of Ecological Effect ................................................ 58 2.8.1 Assessment Endpoints ................................................................................................. 58 2.8.2 Assessment Endpoints for Designated Critical Habitat ............................................... 62 2.9 Conceptual Model ............................................................................................................... 64 2.9.1 Risk Hypotheses ........................................................................................................... 64 2.9.2 Diagram ........................................................................................................................ 65 2.10 Analysis Plan .................................................................................................................... 66 2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model .......................... 66 2.10.1.1 Measures of Exposure ......................................................................................... 67
2.10.1.2 Measures of Effect .............................................................................................. 69 2.10.1.3 Integration of Exposure and Effects ................................................................... 70 2.10.2 Data Gaps ................................................................................................................... 70

3 Exposure Assessment ...........................................................................................71 3.1 Label Application Rates, Intervals and Buffers .................................................................. 71 3.2 Aquatic Exposure Assessment ............................................................................................ 73 3.2.1 Modeling Approach ..................................................................................................... 73 3.2.2 Model Inputs ................................................................................................................ 75
3.2.3 Results .......................................................................................................................... 76 3.2.4 Existing Monitoring Data ............................................................................................ 81 3.2.4.1 Surface Water Monitoring Data ............................................................................ 81 3.2.4.2 Groundwater Monitoring Data .............................................................................. 91 3.2.4.3 Sediment Monitoring Data .................................................................................... 91 3.2.4.4 Atmospheric Monitoring Data .............................................................................. 92 3.3 Terrestrial Animal Exposure Assessment ........................................................................... 99 3.4 Terrestrial Plant Exposure Assessment ............................................................................. 103

4 Effects Assessment .............................................................................................104 4.1 Toxicity of Endosulfan to Aquatic Organisms ................................................................. 106 4.1.1 Toxicity to Freshwater Fish and Aquatic-Phase Amphibians .................................... 108 4.1.1.1 Freshwater Fish: Acute Exposure (Mor tality) Studies – Registrant submitted .. 108 4.1.1.2 Freshwater Fish: Acute Exposure (M ortality) Studies—Open Literature .......... 108 4.1.1.3 Freshwater Fish: Chronic Exposur e (Growth/Reproduction) Studies ................ 108

2

### 4.1.1.4 Freshwater Fish: Sublethal Effects and Additional Open Literature Information

............................................................................................................................... .......... 109 4.1.1.5 Aquatic-phase Amphibian: Acute and Chronic Studies ..................................... 110
4.1.1.6 Freshwater Fish: Endosulfan Sulfate .................................................................. 110 4.1.2 Toxicity to Freshwater Invertebrates ......................................................................... 110 4.1.2.1 Freshwater Invertebrates: Acute Exposure Studies ............................................ 110
4.1.2.2 Freshwater Invertebrates: Acut e Exposure Studies—Open Literature ............... 110 4.1.2.3 Freshwater Invertebrates: Chronic Exposure Studies ......................................... 111 4.1.2.4 Freshwater Invertebrates: Sub-lethal Effects and Additional Open Literature
Information ..................................................................................................................... 111
4.1.2.5 Freshwater Invertebrates: Endosulfan Sulfate .................................................... 111 4.1.2.6 Freshwater Invertebrates: Sediment Toxicity ..................................................... 112 4.1.3 Toxicity to Estuarine/Marine Fish ............................................................................. 112 4.1.3.1 Estuarine/Marine Fish: Acute Exposure (Mortality) Studies .............................. 112 4.1.3.2 Estuarine/Marine Fish: Acute Exposur e (Mortality) Studies—Open Literature 112 4.1.3.3 Estuarine/Marine Fish: Chronic Exposure (Growth/Reproduction) Studies ...... 112 4.1.4 Toxicity to Estuarin e/Marine Invertebrates ............................................................... 113
4.1.4.1 Estuarine/Marine Invertebrates: Acute Exposure (Mortality) Studies ................ 113
4.1.4.2 Estuarine/Marine Invertebrates: Ac ute Exposure (Mortality) Studies—Open
Literature ......................................................................................................................... 114
4.1.4.3 Estuarine/Marine Invertebrates: Ch ronic Exposure (Growth/Reproduction)
Studies ............................................................................................................................. 114
4.1.4.4 Estuarine/Marine Invertebra tes: Open Literature Data ....................................... 115
4.1.4.5 Estuarine/Marine Inverteb rates: Endosulfan Sulfate .......................................... 115 4.1.5 Toxicity to Aquatic-phase Amphibians—Open Literature ........................................ 115 4.1.6 Toxicity to Aquatic Plants ......................................................................................... 117
4.1.7 Freshwater Field/Mesocosm Studies ......................................................................... 118 4.2 Toxicity of Endosulfan to Terrestrial Organisms ............................................................. 119 4.2.1 Toxicity to Birds, Reptiles, and Terrestrial-Phase Amphibians ................................ 120 4.2.1.1 Birds: Acute Exposure (Mortality) Studies ......................................................... 120 4.2.1.2 Birds: Chronic Exposure (Growth, Reproduction) Studies ................................ 120 4.2.1.3 Birds: Open literature Studies ............................................................................. 121
4.2.1.4 Birds: Endosulfan Sulfate ................................................................................... 121 4.2.2 Toxicity to Mammals ................................................................................................. 121 4.2.2.1 Mammals: Acute Exposure (Mortality) Studies ................................................. 121 4.2.2.2 Mammals: Chronic Exposure (Growth, Reproduction) Studies ......................... 122
4.2.2.3 Mammals: Endosulfan Sulfate ............................................................................ 122 4.2.3 Toxicity to Terrestrial Invertebrates .......................................................................... 122
4.2.3.1 Terrestrial Invertebrates: Ac ute Exposure (Mortality) Studies ........................... 123
4.2.3.2 Terrestrial Invertebrates: Open Literature Studies .............................................. 123 4.2.4 Toxicity to Terrestrial Plants ..................................................................................... 124 4.3 Use of Probit Slope Response Relationship to Provide Information on the Endangered Species Levels of Concern ...................................................................................................... 124 4.4 Ecological Incident Summary ........................................................................................... 125

5 Risk Characterization ........................................................................................127

5.1 Risk Estimation ................................................................................................................. 127

3

### 5.1.1 Exposures in the Aquatic Habitat .............................................................................. 128 5.1.1.1 Freshwater Fish and Aquatic-phase Amphibians ............................................... 128
5.1.1.2 Freshwater Invertebrates ..................................................................................... 129 5.1.1.3 Non-vascular Aquatic Plants ............................................................................... 131 5.1.1.4 Aquatic Vascular Plants ...................................................................................... 131 5.1.2 Exposures in the Terrestrial Habitat .......................................................................... 131 5.1.2.1 Birds (surrogate for Reptiles and Terrestrial-phase amphibians) ....................... 131
5.1.2.2 Mammals............................................................................................................. 135
5.1.2.3 Terrestrial Invertebrates ...................................................................................... 138
5.1.2.4 Terrestrial Plants ................................................................................................. 140 5.1.3 Primary Constituent Elements of Designated Critical Habitat .................................. 140 5.1.4 Spatial Extent of Potential Effects ............................................................................. 140 5.1.4.1 Spray Drift .......................................................................................................... 140 5.1.4.2 Downstream Dilution Analysis ........................................................................... 141 5.1.4.3 Overlap between CRLF, CTS, SFGS, BCB, VELB, SMHM, and SJKF habitat and Spatial Extent of Potential Effects ........................................................................... 141 5.2 Risk Description ................................................................................................................ 143 5.2.1 California Red-Legged Frog...................................................................................... 163
5.2.1.1 Direct Effects ...................................................................................................... 163 5.2.1.2 Indirect Effects to CRLF (via Potential Loss of Prey) ........................................ 178 5.2.1.3 Indirect Effects (via Habitat Effects) .................................................................. 185 5.2.1.4 Effects to Designated Critical Habitat ................................................................ 186 5.2.2 California tiger salamander ........................................................................................ 187
5.2.2.1 Direct Effects .......................................................................................................... 187 5.2.2.2 Indirect Effects ( via Reductions in Prey Base )................................................... 191
5.2.2.3 Modification to Desi gnated Critical Habitat ....................................................... 193
5.2.3 San Francisco Garter Snake ....................................................................................... 194
5.2.3.1 Direct Effects ...................................................................................................... 194 5.2.3.2 Indirect Effects ( via Reductions in Prey Base )................................................... 196 5.2.3.3 Indirect Effects ( via Habitat Effects ) .................................................................. 198
5.2.4 Salt Marsh Harvest Mouse......................................................................................... 199
5.2.4.1 Direct Effects ...................................................................................................... 199 5.2.4.2 Indirect Effects ( via Reductions in Prey Base )................................................... 202 5.2.4.3 Indirect Effects ( via Habitat Effects ) .................................................................. 203 5.2.5 San Joaquin Kit Fox ................................................................................................... 204
5.2.5.1 Direct Effects ...................................................................................................... 204 5.2.5.2 Indirect Effects ( via Reductions in Prey Base )................................................... 206 5.2.5.3 Indirect Effects ( via Habitat Effects ) .................................................................. 208 5.2.6 Bay Checkerspot Butterfly ......................................................................................... 208
5.2.6.1 Direct Effects ...................................................................................................... 208 5.2.6.2 Indirect Effects (via Reduction in Prey Base & Habitat Effects) ....................... 210
5.2.6.3 Modification to Desi gnated Critical Habitat ....................................................... 210 5.2.7 Valley Elderberry Longhorn Beetle ........................................................................... 211
5.2.7.1 Direct Effects ...................................................................................................... 211 5.2.7.2 Indirect Effects ( via Reduction in Prey Base & Habitat Effects ) ....................... 212
5.2.7.3 Modification to Desi gnated Critical Habitat ....................................................... 213

4

### 6 Uncertainties .......................................................................................................214 6.1 Exposure Assessment Uncertainties ................................................................................. 214
6.1.1 Maximum Use Scenario ............................................................................................. 214 6.1.2 Aquatic Exposure Modeling of Endosulfan ............................................................... 214
6.1.2.1 Potential Groundwater Contributions to Surface Water Chemical Concentrations

............................................................................................................................... .......... 216 6.1.3 Multiple Growi ng Seasons per Year .......................................................................... 217 6.1.4 Usage Uncertainties ................................................................................................... 217 6.1.5 Terrestrial Exposure Modeling of Endosulfan ........................................................... 217 6.1.6 Spray Drift Modeling ................................................................................................. 219
6.2 Effects Assessment Uncertainties ..................................................................................... 220 6.2.1 Age Class and Sensitivity of Effects Thresholds ....................................................... 220 6.2.2 Use of Surrogate Species Effects Data ...................................................................... 220
6.2.3 Sublethal Effects ........................................................................................................ 221 6.2.4 Location of Wildlife Species ..................................................................................... 221 6.2.5 Endocrine Disruption ................................................................................................. 221

7 Summary and Conclusions ................................................................................222

8 References ...........................................................................................................232

5

## Appendices

Appendix A Endosulfan Label Analysis and Memorandum Appendix B AgDrift Modeling Appendix C Aquatic Exposure Modeling Approach for Endosulfan Appendix D RQ Method and LOCs Appendix E GIS Maps Appendix F T-REX Example Output Appendix G Bibliography of ECOTOX Open Literature Not Evaluated Appendix H Accepted ECOTOX Data Table (s orted by effect) and Bibliography Appendix I KABAM Model Description and Output Appendix J Aquatic ECOTOX Data Appendix K Terrestrial ECOTOX Data Appendix L Endosulfan Incidents Appendix M HED Effects Table Appendix N Earthworm Fugacity Modeling



## Attachments

Attachment 1: Status and Life History for the CRLF
Attachment 2: Baseline Status and Cumulative Effects for the CRLF
Attachment 3: Status and Life History for the San Francisco Bay Species
Attachment 4: Baseline Status and Cumulative Effe cts for the San Francisco Bay Species



## List of Tables

Table 1.1 Effects Determination Summary for Eff ects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB 15 Table 1.2 Effects Determination Summary fo r the Critical Habitat Impact Analysis 22 Table 2.1 Physiochemical properties of the multi-chemical stressor 32 Table 2.2 Summary of fate and transport pr operties for endosulfan isomers and sulfate 33
Table 2.3 Endosulfan labeled uses assessed for Ca lifornia (No single applic ation rate over 1.5 lbs except for orchard crops and strawberries) 37 Table 2.4 California labeled non-crop use for endosulfan 40 Table 2.5 Top use patterns for endosulfan for selected years from 1990 to 2002 41 Table 2.6 Historical usage of endosulfan for 1994 (1 st 

### period) and 1995-1997 (2 nd 

### period) 43 Table 2.7 Historical usage of endosulfan for 1998-2004 (3 rd 

### period) and 2005-2006 (4 th 

### period)
44 Table 2.8 Summary of Current Distribution, Habita t Requirements, and Life History Information for the Assessed Listed Species 49 Table 2.9 Designated Critical Habitat PC Es for the CRLF, CTS, BCB and VELB 53 Table 2.10 Taxa Used in the Analyses of Direct and Indirect Effects of Endosulfan for the Assessed Listed Species. 60 Table 2.11 Taxa and Assessment Endpoints Used to Evaluate the Potential for the Use of
Endosulfan to Result in Dir ect and Indirect Effects to the Assessed Listed Species. 61

6

### Table 2.12 Summary of Assessment Endpoints and M easures of Ecological Effect for Primary Constituent Elements of Designated Critical Habitat for CRLF, BCB, VELB, and CTS.
62 Table 3.1 Summary of labeled endosulfan uses , scenarios, and app lication information 71 Table 3.2 Calculation of application rates for α - and β -endosulfan and endosulfan sulfate) for use in modeling (rates are for almond) 74 Table 3.3 Summary of PRZM/EZAMS enviro nmental fate and transport data of α - and β

endosulfan and endosulfan sulfate used as aquatic exposure inputs for this endangered species assessment 75 Table 3.4 Aquatic EECs ( μ g/L) for endosulfan used in California ( α - and β -endosulfan) 1 

### 76 Table 3.5 Aquatic EECs ( μ g/L) for endosulfan used in Calif ornia (endosulfan sulfate and total stressor) 77 Table 3.6 Sediment pore water EECs ( μ g/L) for endosulfan used in California ( α - and β

endosulfan) 78 Table 3.7 Sediment pore water EECs ( μ g/L) for endosulfan used in California (endosulfan sulfate and total stressor) 78 Table 3.8 Sediment EECs ( μ g/L) for endosulfan used in California ( α - and β -endosulfan) 79 Table 3.9 Sediment EECs ( μ g/L) for endosulfan used in Califo rnia (endosulfan sulfate and total stressor) 79 Table 3.10 Total soil and pore water concen trations for selected crop scenarios 81 Table 3.11 Summary of reported detection limits for the CDPR surface water data 83 Table 3.12 Summary of CPDR surface water mon itoring data for Califor nia Counties collected
for the first monitoring period (1991 to 1996) 83 Table 3.13 Summary of CPDR surface water monitoring data for California (the 2 nd 

### monitoring period) 85 Table 3.14 Summary of STORET surface wa ter monitoring data for California 87 Table 3.15 A summary of NAW QA monitoring data for surface water from California 89 Table 3.16 Surface water data summary 90 Table 3.17 A summary of monitoring da ta for ground water from California 91 Table 3.18 A summary fo r NAWQA monitoring data to base sediment in California 91 Table 3.19 Summary of bottom sediment monitoring data for California 92 Table 3.20 Frequency and concentrations of endosulfan species in ambient air 94 Table 3.21 Frequency and concentrations of endosulfan species in ambient air 96 Table 3.22 Concentration of pesticides (ng/L) in surface water samples collected at the Tablelands (Sequoia National Park), and th e Sixty Lake Basin (Kings Canyon National Park) California, USA (Fellers et al. 2004). 98 Table 3.23 Summary of Dose and Dietary-based EECs Used for Estimating Dietary Risks to Terrestrial Organisms using T-REX ver. 1.4.1. 100 Table 4.1 Aquatic Toxicity Profile for Endosulfan (TGAI) 107 Table 4.2 Categories of Acute Toxicity for Fish and Aquatic Invertebrates 108
Table 4.3 Terrestrial Toxici ty Profile for Endosulfan 119 Table 4.4. Categories of Acute Toxic ity for Avian and Mammalian Studies 119 Table 4.5 Comparison of Acute Toxicity of Endosulfan and Endosulfan Sulfate To Birds. 120 Table 5.1 Acute and Chronic RQs fo r freshwater fish based on EEC s for use categories used to represent all endosulfan uses in CA. 128

7

### Table 5.2 Acute and Chronic RQs for freshwater invertebrates based on EECs for use categories used to represent all endosulfan uses in CA. 130 Table 5.3 Summary of the acute and chronic dose- and dietary- based RQs for birds (20 g)
estimated based on the maximum endosulfan foliar spray applications using T-REX
version 1.4.1. 132 Table 5.4 Summary of the acute and chronic dose- and diet ary-based RQs for mammals
estimated based on the maximum endosulfan foliar spray applications using T-REX
version 1.4.1. 136 Table 5.5 Summary of the acute and chronic dose- and dietary- based RQs terrestrial insects
estimated based on the maximum endosulfan foliar spray applications using T-REX
version 1.4.1. 139 Table 5.6 Summary of the highest RQ to LOC ratios for the two GIS use categories for
endosulfan 141 Table 5.7 Summary of average endosulfan usage data and occurrence of the CRLF and the San Francisco Bay species at the county level 141
Table 5.8 Extent and location of overlap between areas of sp ecies occurrence and areas of potential endosulfan usage 142 Table 5.9 Risk Estimation Summary for endos ulfan - Direct and Indirect Effects 144 Table 5.10 Risk Estimation Summary for Endosulfa n – Effects to Designated Critical Habitat (PCEs) 145 Table 5.11 Summary of the chance of individual acute effects to freshwater animals based on acute RQs, the acute listed species LOC, acu te toxicity data, a nd probit slope response relationships (1,2)



### . 148 Table 5.12 Summary of the chance of individual acute effects to terrestrial animals based on acute RQs, the acute listed species LOC, acu te toxicity data, a nd probit slope response relationships. 150 Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC, acute toxicity data, and probit slope response relationships. 158 Table 5.14 Comparison of maximum detected con centrations of total endosulfan in surface waters of California to Agen cy LOC for freshwater fish 166 Table 5.15 Assumed dietary preferences of smal l (1.4g), medium (37g) and large (238g) CRLF feeding on aquatic biota of the model ecosystem. 169
Table 5.16 Endosulfan chemical charac teristics used as input to KABAM 169
Table 5.17 Estimated concentrations of endosul fan in ecosystem components for two crop exposure scenarios 170
Table 5.18 Calculation of EECs for CRLF consumi ng aquatic prey contaminated by endosulfan
171 Table 5.19 Calculation of RQ values for CRL F consuming aquatic prey contaminated by
endosulfan. 171 Table 5.20 Summary of the acute and chronic dos e- and dietary-based RQs for herpetofauna
estimated based on the maximum endosulfan foliar spray applications using T-HERPS
version 1.0. 174 Table 5.21 Acute and Chronic RQs for freshwater sediment invertebrates based on EECs for use categories used to represent all endosulfan uses in CA 182

8

### Table 5.22 Estimated concentrations of total en dosulfan in earthworms and avian risk quotients for two crop exposure scenarios. 190
Table 5.23 Estimated concentrations of total endosulfan in earthworms and mammalian risk quotients for two crop exposure scenarios 201 Table 7.1 Effects Determination Summary for Eff ects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB 222 Table 7.2 Effects Determination Summary fo r the Critical Habitat Impact Analysis 229



## List of Figures

Figure 2.1 Chemical structures of endosulfan and related compounds ........................................ 31 Figure 2.2 Endosulfan Use in Total Pounds per C ounty (note vlues are different in chosen categories) ..................................................................................................................... 42 Figure 2.3 Historical usage data for endosulfan .......................................................................... 43 Figure 2.4 Endosulfan usage and acreage for the top five crop use patt erns (CA-PUR data; Average for 2005-2006) ................................................................................................ 47 Figure 2.5 Distribution of endosulfan usage for the top usage counties of Fresno, Kings, and Imperial ......................................................................................................................... 48 Figure 2.6 Initial area of concern, or “foot print” of potential use, for endosulfan ....................... 57 Figure 2.7 Conceptual Model for Endosulfan Effect s on the Assessed Species and their Critical Habitat in the Aquatic Environment .............................................................................. 65 Figure 2.8. Conceptual Model for Endosulfan Eff ects on the Assessed Species and their Critical
Habitat in the Terrestrial Environment .......................................................................... 66 Figure 3.1 Detected concentrations of alpha and beta-endosulfan and common degradate in
California surface waters from 1991 to 2006 (No data were collected from 1996 to 2000). ............................................................................................................................. 82 Figure 3.2 Detected concentrations of the total endosulfan species in Ca lifornia surface waters
from 1991 to 2006 ......................................................................................................... 82 Figure 3.3 CPDR Monitoring data for Imperial County (11 sites, varied times of the year) ....... 84 Figure 3.4 CDPR Monitoring data for Merced County (4 sites), Stanislaus County (6 sites), San Joaquin County (2 sites) and Sacramento C ounty (1 site) at varied times of the year .. 85 Figure 3.5 Detected concentrations of α - and β -endosulfan and endosulfan sulfate common degradate in California surface waters from 2001 to 2008 (STORET data) ................. 88 Figure 3.6 Detected concentrations of the total endosulfan species in Ca lifornia surface waters from 2001 to 2008 (STORET data) ............................................................................... 88 Figure 3.7 Detected concentrations of α - and β -endosulfan and endosulfan sulfate common degradate in surface waters of five Califor nia Counties (Counties wi th detections over the LOQ; 2001 to 2008 STORET data) ........................................................................ 89 Figure 3.8 Concentration profiles for α - and β - endosulfan at the edge a nd near-field in ambient air following application in San Joaquin County, California ........................................ 94 Figure 3.9 Concentration profiles for α - endosulfan in ambient air during a period of five weeks at 4 sites in Fresno County, California. ......................................................................... 97 Figure 5.1 Temporal distribution of endosulfan application in California for 2006 (Source: CDPR PUR)) ............................................................................................................... 164 Figure 5.2 CRLF Reproductive Events by Month; Adults and juven iles can be present all year.

............................................................................................................................... ...... 164

9

### Figure 5.3 Species sensitivity distribution of the acu te toxicity of endosul fan to freshwater fish

............................................................................................................................... ...... 167 Figure 5.4 Species sensitivity distribution of the acute toxicity of endos ulfan to freshwater invertebrates via water column exposure .................................................................... 180 Figure 5.5 Species sensitivity distribution of the acute contact toxicity of endosulfan TGAI to
terrestrial invertebrates ba sed on species mean values. .............................................. 183 Figure 5.6 CTS Reproductive Events by Month; Adu lts and juveniles can be present all year . 188 Figure 5.7 Average Endosulfan Use (2005-2006) in Counties with Re ported Occurrence of Listed Species, Occupied Core Areas and/or Critical Habitat .................................... 189 Figure 5.8 SFGS Reproductive Events by M onth; Adults can be present all year ..................... 195 Figure 5.9 General Annual Life-History Parameters for the BCB ............................................. 209

10

# 1 Executive Summary

The purpose of this assessment is to evaluate potential direct and i ndirect effects on the following species arising from FIFRA regulat ory actions regarding use of endosulfan on agricultural sites: California red-legged frog (CRLF), Rana aurora draytonii California Tiger Salamander (CTS), Ambystoma californiense, San Francisco Garter Snake (SFGS), Thamnophis sirtalis tetrataenia

, Salt Marsh Harvest Mouse (SMHM), Reithrodontomys raviventris, San Joaquin Kit Fox (SJKF), Vulpes macrotis mutica

, Bay Checkerspot Butterfly (BCB), Euphydryas editha bayensis, and Valley Elderberry Longhorn Beetle (VELB), Desmocerus californicus dimorphus

.

In addition, this assessment evaluate s whether these actions can be e xpected to result in effects to designated critical habitat for th e CRLF, CTS, BCB, and VELB; no ting that critical habitat has not been designated for the SFGS, SMHM and SJKF. This assessment was completed in
accordance with the U.S. Fish and Wildlife Se rvice (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 listing date and a general description of th e range of each assessed species are as follows.

• 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 co astal 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.

• The CTS was listed as threatened by the Fi sh and Wildlife Servi ce on August 4, 2004 and designated critical habitat was establishe d on November 24, 2004. The two distinct population segments (one in Santa Barbara County and the other in Sonoma County) inhabit freshwater pools or ponds, grassland or oak savannah communities in low foothill regions and small mammal burrows.

• The SFGS was listed as an endangered species by the USFWS in 1967 and was grandfathered under the Endangered Species Ac t (ESA) when it was signed into law in
1973. The SFGS is endemic to the San Franci sco Peninsula and San Mateo County and historically inhabited densel y vegetated ponds or shallow marshlands near open hillsides found from San Francisco to Santa Cruz, in cluding the San Francisco Peninsula. The
current distribution of the SFGS is unknown becau se most of their historic range is now privately owned; however, it appears that th e SFGS can still be found in much of its historic range.

• The SMHM was listed as an endangered species by the USFWS in 1970. The SMHM is currently found in tidal and non-tidal salt marshes in Sa n Francisco, San Pablo, and Suisun bays.

• The SJKF was listed as endangered by th e USFWS on March 11, 1967. Its current range includes Alameda, Contra Costa, Fresno, Ke rn, Kings, Madera, Merced, Monterey, San

11

### Benito, San Joaquin, San Luis Obispo, Santa Ba rbara, Santa Clara, Stanislaus, Tulare and
Ventura counties in California. It inhabits a variety of habitats, including grasslands, scrublands, vernal pool areas, oak woodl and, alkali meadows and playas, and an agricultural matrix of row crops, irrigated pastures, orchards, vineyards, and grazed annual grasslands.

• The BCB was listed as a threatened species in 1987 by the USFWS. The species primarily inhabits native grasslands on serp entine outcrops around th e San Francisco Bay
Area in California. The dist ribution of known BCB populations is currently limited to
Santa Clara and San Mateo Counties.

• The VELB was listed as threatened on August 8, 1980 by the USFWS. The species inhabits the Central Valley of California (from Shasta C ounty to Fresno County in the San Joaquin Valley). The VELB is complete ly dependent on its hos t plant, elderberry ( Sambucus species ), which is a common component of the remaining riparian forests and adjacent upland habitats of California’s Central Valley.

Endosulfan is a dioxathiepin broad spectrum contact insecticide and acarici de that is broadly classified as a chlorinated hydrocarbon. The ch emical is used on major agricultural crops to control insect pests such as aphids, fruitworms, beetles, leafhoppers, moth larvae, and whiteflies.
Labeled uses of endosulfan incl ude a wide variety of vegetabl es, fruits, nuts, outdoor tree nurseries, and cotton. The following uses are consid ered as part of the federal action evaluated in this assessment: nut trees, non-bearing citrus tr ees, cole crops, fresh market sweet corn, cotton, pome/stone fruits, leafy vegetabl es, cucurbits, outdoor nurseries for ornamentals and shade trees, potato, sweet potato, dry beans and peas, carrot, and fruiting vegeta bles. Endosulfan is applied as liquid spray prepared from emulsifiable concen trates and wettable powder formulations using aircraft or ground equipment. The pesticide is mo stly applied as foliar spray with single rates ranging from 0.5 to 2.5 lbs a.i/A at minimum inte rvals ranging from 5 to 10 days and maximum total rate from 0.5 to 3.0 lb a.i/season or year.

Endosulfan is a 70:30 mixture of two biologically-active isomers ( α and β ). The isomers differ in their physiochemical and fate properties. Th e chemical is relatively persistent and semivolatile. The β -isomer is generally more persistent and the α -isomer is more volatile. Under sterlie neutral/basic conditions, hydrolysis is an important degrad ation route; however, endosulfans are persistent under ac idic conditions. With the excep tion of hydrolysis in alkaline conditions, microbial degradation in soils is the predominant r oute of endosulfan degradation. The major transformation products found in the fate studies are endosulfan diol (hydrolysis) and endosulfan sulfate (soil metabolism). Both the di ol and sulfate transformation products have the backbone structures of the parent compound.

Based on a review of the environmental fate data and use character ization for endosulfan, endosulfan sulfate is considered the major degradat e of concern that is a ddressed in this risk assessment. Based on limited data, endosulfan sulf ate appears to have similar acute toxicity to aquatic and terrestrial species (i.e ., within an order of magnitude) and is assumed to have similar chronic toxicity. Endosulfan sulfat e is also more persistent than the parent isomers (alpha, beta endosulfan) and tends to be a ma jor component of total endosulfa n residues found in biologically active environmental media (e.g., aer obic soil). Endosulfan diol a ppears to form in only minor

12

### quantities in the soil system and is reported to be substantially less toxic than either the parent or its major degradation product, endosulfan sulfate.

Endosulfans have a high affinity for sorption onto soil and are not expected to be highly mobile. Endosulfan can move via spray drift and run-o ff causing contamination of surface waters where it is expected to reside in sediments. As a re sult of endosulfan volatilit y, the chemical can move to targets beyond its use area thr ough atmospheric transport (vol atilization and/or transport on dust particles). In this assessment, spray drift and runoff are considered quantitatively while atmospheric transport and volatilization are consid ered qualitatively as th e potential transport
mechanisms for endosulfan.

Available monitoring data from California sugge st that endosulfan is present in important environmental compartments, although endosulfa n use and concentrations in surface water appear to be declining. The chemical isomers and/or their common sulfat e degradate have been detected in a variety of off-target locations in California, including rain and snow in the mountains (McConnell et al, 1998), ground water (Fellers et al ., 2004), surface water (STORET database, CDPR, 2000), stream sediment (West on et al., 2004; U.S. EPA, 1997), tadpole and adult frog tissues (Sparling et al., 2001), and ambient air (Air Res ource Board “ARB” of California ( refer to Section 3.2.4.4 Atmospheric Monitoring Data ).

The effects determinations for each listed speci es assessed is based on a weight-of-evidence method that relies heavily on an evaluation of risk s to each taxon relevant to assess both direct and indirect effects to the listed species and the potential for effects to their designated critical habitat ( i.e ., a taxon-level approach). Since the assessed species exist within aquatic and terrestrial habitats, exposur e of the listed species, their prey and their habitats to endosulfan are assessed separately for the two habitats. Tier- II aquatic exposure models are used to estimate high-end exposures of endosulfan in aquatic habi tats resulting from runoff and spray drift from
different uses. Peak model-estimated environm ental concentrations, re sulting from different endosulfan uses, ranged from 0.72 to 5.88 μg/L for the total α - and β - endosulphan and endosulfan sulfate. 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 and the California Department of Pesticide Regulation. The maximum concentration of endosulfan reported by the California Department of Pesticide Regulation surface water database (0.95 μg/L from the 1991 to 2006 time period) is roughly 6 times lower than the highest peak model- estimated environmen tal concentration. The concentrations of endosulfan reported by NAWQA for California surface waters were below the limits of analytical detection (ran ging from 0.0047 to 0.022 μg/L depending on the endosulfan compound measured).

To estimate endosulfan exposures to terrestrial species resulting from uses involving endosulfan foliar applications, the T-REX model is used. This model provides estimates of endosulfan residues on forage items (e.g., short grass, tall gra ss, insects, and seeds) that result from direct deposition on the field. A refinement of this mo del (T-HERPS) is also us ed to enable further characterization of dietary expos ures to terrestrial-phase amphi bians and reptiles, based on food consumption and dietary preferences specific to herptivores. AgDRIF T and AGDISP (Teske and Curbishley, 2003) models are also used to estimate deposition of endosulfan on terrestrial and

13

### aquatic habitats from spray drift. For consump tion of contaminated terr estrial prey (e.g., soildwelling invertebrates), a fugacity-based eart hworm bioaccumulation model is also used to
characterize direct or indirect e ffects on listed species. To address consumption of contaminated aquatic prey (e.g., fish and aquati c invertebrates), the KABAM model 1 

### is used to estimate endosulfan exposures to listed sp ecies via the aquatic food web.

The effects determination assessment endpoints for the listed species include direct toxic effects on the survival, reproduction, and growth of the list ed species itself, as we ll as indirect effects, such as reduction of the prey base or modificatio n of its habitat. If appropriate data are not available, toxicity data for bi rds are generally used as a surr ogate for reptiles and terrestrialphase amphibians and toxicity data from fish are used as a surrogate for aquatic-phase amphibians. For endosulfan, equal toxicity was assumed between the alpha, beta and endosulfan sulfate compounds, based on similarity in struct ures, mode of action, and limited data on the comparative acute toxicity of these compounds. Therefore, modeled or measured environmental exposures of total endosulfan (sum of alpha, beta and endosulfan sulfate) were compared with toxicity data for the Technical Grade Active Ingredient (TGAI). For sediment-borne exposures, toxicity data were available only for endosulfan sulfate, and thus, comparisons of total endosulfan EECs were made to toxicity estimates for endosulfan sulfate.

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 endosulfan use within the action area has the pote ntial to adversely affect the assessed species and designated critical habitat if applicable, via direct toxicity or indirectly based on direct effects to its food supply or habitat. When RQ s for each particular type of effect are below LOCs, the pesticide is determined to have “ no effect” on the listed species being assessed. Where RQs exceed LOCs, a potential to cause ad verse effects is identified, leading to a conclusion of “may affect.” If a determination is made that use of endosulfan “may affect” the listed species being assessed and/or its designated critical hab itat (if applicable), additional information is considered to refine the potenti al for exposure and effects. Best available information is used to distinguish those actions that “may affect, but ar e not likely to adversely affect” (NLAA) from those actions that are “l ikely to adversely affect” (LAA) for each listed species assessed. For designated cr itical habitat, distinctions are made for actions that are expected to have ‘no effect’ on a designated critical habitat from those actions that may have an effect on designated cr itical habitat.

Based on the best available information, the Agency makes a May Affect and Likely to Adversely Affect (LAA) determination for th e CRLF, CTS, SFGS, SMHM, SJKF, BCB, and
VELB from the use of endosulfan. A summa ry of the risk conclusions and effects determinations for each listed species assessed here and their designate d critical habitat (if applicable) is presented in Table 1.1 and Table 1.2 Further information on the results of the
effects determination is included as part of the Risk Description in Section 5.2 . Additionally, the Agency has determined that there is the potential for effects to critical habitat of CRLF and CTS
from the use of the chemical. This LAA determina tion is based on the potent ial for direct effects (to both aquatic and terrestria l-phase CRLF, SFGS, CTS, BCB, VELB, SMHM, SJKF), indirect effects due to potential decreases in aquatic and terrestrial prey items, and the potential for

1 http://www.epa.gov/oppefed1/models/water/index.htm#KABAM



### 14

### effects to designated critical habitat due to the pote ntial loss of aquatic and te rrestrial prey items. Given the LAA determination for the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and potential modification of designa ted critical habitat for CRLF a nd CTS, a description of the baseline status and cumulative effects for the CRLF is provided in Attachment 2 and the
baseline status and cumulative effects for th e SFGS, CTS, BCB, VELB, SMHM and SJKF is provided in Attachment 4

.

Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects
Determination 1 Basis for Determination

POTENTIAL FOR DIRECT EFFECTS Aquatic-phase CRLF (Eggs, Larvae, and Adults) : Freshwater Fish RQ - Acute RQs for freshwater fish (used as a surrogate for aquatic-phase CRLFs) exceed the listed species acute risk LOC fo r all 20 modeled crop scenarios. - Chronic RQs for freshwater fish (used as a surrogate for aquatic-phase CRLFs)
exceed the chronic risk LOC for a ll 20 modeled crop scenarios.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for freshwater fish (surrogate for aquatic-phase CRLFs) is as high as ~1 in 1.

Ecological Incident Reports - 67 of the 83 endosulfan-associated ecological incidents reported to the Agency
involve fish and 53 of these ar e classified as ‘probable’ or ‘highly probable;’ 18 of the 20 incident reports associated with ‘registered uses’ involved mortality to fish.

Species Sensitivity Differences - Model-based EECs exceed the LOC for approximately 80 to 97% of the tested freshwater fish species

Surface Water Monitoring Data - The highest reported values of total endosulfan in California equal or exceed the
acute LOC for freshwater fish.

Bioaccumulation in Aquatic Prey - Based on consumption of aquatic prey that is predicted to bioaccumulate endosulfan, acute dose-based RQs exceed the acute listed LOC in all 20 crop exposure scenarios modeled for small, medium and large CRLF.

Temporal and Spatial Overlap - Based on current endosulfan use data and potential endosulfan use on agricultural crops/orchards/vineyard areas, there appears to be a potential for both temporal and spatial overlap between aquatic-phase CRLF distribution and endosulfan agricultural use ( Appendix E ).California redlegged frog ( Rana aurora

draytonii )

(CRLF) LAA 1

Terrestrial-phase CRLF (Juveniles and Adults) : Direct Deposition on Forage Items: Avian RQ - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.



### 15Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; and acute dietary-based species/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (sur rogate for terrestrial - phase CRLFs) and herpetofauna based on direct deposition onto food items is as high
as ~1 in 1.

Temporal and Spatial Overlap - Based on current endosulfan use data and potential endosulfan use on agricultural crops/orchards/vineyard areas, there appears to be a potential for both temporal and spatial overlap between terrestrial -p hase CRLF distribution and endosulfan agricultural use ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS CRLF Aquatic Prey Items, Aquatic Habita t, Cover and/or Primary Productivity Freshwater fish and aquatic-phase amphibians : - Acute and chronic RQs exceed the liste d species acute and chronic LOCs; high likelihood of individual mortality, EECs exceed the LOC for 80 % or more of the tested fish species and a large number of aquatic incidents involving fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

. Freshwater Invertebrates : -Acute and chronic RQs for freshwater in vertebrates exceed the listed species acute
and chronic risk LOC for all 20 cr op exposure scenarios modeled. -The chance of individual effects ( i.e ., mortality) for freshwat er invertebrates is as high as ~1 in 1. - Model-based EECs exceed the LOC for approximately 45% to 60% of the tested freshwater invertebrate species - The highest reported values of total endosulfan in California equal or exceed the
listed acute LOC and chronic LOC for freshwater invertebrates. CRLF Terrestrial Prey Items, Riparian Habitat Terrestrial-phase Amphibians : - Exceedence of acute and chronic LOCs for terrestrial-phase amphibians as described above for CRLF (see “ Potential Direct Effects; Terrestrial Phase CRLF [juveniles and adults]) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively. -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.
- When indirect effects are considered via ex posure of terrestrial insects to spray drift, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source ( Appendix E ).



### 16Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
Small Mammals: Direct Deposition on Forage Items - Acute and chronic dose-based RQs for small mammals foraging on food items receiving direct deposition of applied e ndosulfan exceed the acute listed LOC for mammals in all 20 crop scenarios modeled - Chronic diet-based RQs for small mammals foraging on food ite ms receiving direct deposition of applied endosulfan exceed the chronic LOC for mammals in 13 of the 20 crop scenarios modeled - The chance of individual effects ( i.e ., mortality) for small mammals is as high as ~1
in 1.

Small Mammals: Bioaccumulation in Terrestrial Prey - RQs exceed of acute listed and chronic LOCs in all 20 exposure scenarios modeled based on small mammals eating earthworms that are predicted to bioaccumulate
endosulfan from soil.
POTENTIAL FOR DIRECT EFFECTS California tiger
salamander

( Ambystoma californiense LAA 1

Direct Deposition on Forage Items: Avian RQ (Terrestrial-Phase CTS) - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; acute dietary-based sp ecies/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (s urrogate for reptiles and terrestrial phase amphibians) and herpetofauna based on direct deposition onto food items is as high as ~1 in 1.

Bioaccumulation in Aquatic Prey - Based on consumption of aquatic prey that is predicted to bioaccumulate endosulfan, acute dose-based RQs exceed the acute listed LOC in all 20 crop exposure scenarios modeled for small CRL F (used as surrogate for CTS exposure potential).

Bioaccumulation in Terrestrial Prey - Based on consumption of terrestrial prey (earthworm) that is predicted to bioaccumulate endosulfan, acute dose-bas ed RQs and chronic diet-based RQs for small birds (surrogate for terrestrial-phas e amphibians) exceed the acute listed and chronic LOCs in all 20 crop exposure scenarios modeled.

Freshwater Fish (Aquatic-phase CTS) : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”



### 17Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of CTS was
identified.

- A large amount of spatial overlap between CTS occurrence and current (and potential future use) of endosulfan was identified ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS

Freshwater Fish : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

Freshwater Invertebrates: - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, and exceedence of LOCs for 45-60% of freshwater invertebrate species tested, as described above for CRLF (see “ Potential Indirect Effects; CRLF Aquatic Prey Items, Aquatic Habitat, Cover and/or Primary Productivity) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)
POTENTIAL FOR DIRECT EFFECTS San Francisco garter snake ( Thamnophis
sirtalis

tetrataenia ) LAA 1
Direct Deposition on Forage Items: Avian RQ - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; and acute dietary-based species/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (s urrogate for reptiles and terrestrial phase amphibians) and herpetofauna based on direct deposition onto food items is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of SFGS was
identified. - No spatial overlap identified at the County level based on current endosulfan use reported for California. If cultivated crop /orchard/vineyard uses are considered areas



### 18Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

of potentia l endosulfan use in the future, then a substantial amount of spatial overlap
can be observed relative to the tota l area of SFGS occurrence sections ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS Prey Items, Habitat, Cover And/Or Primary Productivity
Freshwater Fish : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

Freshwater Invertebrates: - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, and exceedence of LOCs for 45-60% of freshwater invertebrate species tested, as described above for CRLF (see “ Potential Indirect Effects; CRLF Aquatic Prey Items, Aquatic Habitat, Cover and/or Primary Productivity) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Terrestrial Vertebrates
- Acute and chronic LOC exceedence for bird s (surrogate for reptiles and terrestrialphase amphibians) and herpetofauna for direct deposition on food items, a high
likelihood of individual mortality, and RQ exceedence of acute listed LOC and chronic LOC based on consumption of terrestrial and aquatic prey by birds and mammals as described above for the CRLF (see “ Potential Direct Effects; Terrestrial Phase CRLF [juveniles and adults] and “Potential for Indirect Effects: CRLF Terrestrial Prey Items, Riparian Habitat) ”
POTENTIAL FOR DIRECT EFFECTS Salt marsh
harvest mouse ( Reithrodonto

mys raviventris )

(SMHM) LAA 1
Direct Deposition on Forage Items: Mammalian RQ - Acute and chronic dose-based RQs for small mammals foraging on food items receiving direct deposition of applied e ndosulfan exceed the acute listed LOC for mammals in all 20 crop scenarios modeled - Chronic diet-based RQs for small mammals foraging on food ite ms receiving direct deposition of applied endosulfan exceed the chronic LOC for mammals in 13 of the 20 crop scenarios modeled

Likelihood of Individual Mortality - The chance of individual effects ( i.e ., mortality) for small mammals resulting from direct deposition onto forage items is as high as ~1 in 1.

Bioaccumulation in Terrestrial Prey - RQs exceed of acute listed and chronic LOCs in all 20 exposure scenarios modeled based on small mammals eating earthworms that are predicted to bioaccumulate
endosulfan from soil.

Temporal and Spatial



### 19Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
- Temporal overlap between endosulfan app lication and all life stages of the SMHM
was identified. - A small amount of spatial overlap identif ied at the County level based on current endosulfan use reported for California and based on areas of potentia l endosulfan use in the future (i.e., cultivated crop, orchard and vineyard use areas). - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase SMHM exposure, particularly in ar eas of potential endosulfan use west of SMHM occurrence sections in Solano County ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS Prey items, habitat, cover and/or primary productivity
Terrestrial invertebrates :

-- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Birds and Mammals (rearing sites) : - Acute and chronic RQ for birds and mamm als (whose rearing sites are potentially used by SMHM) exceed listed acute and chroni c LOCs as a result of direct deposition onto forage items and bioaccumulation in terrestrial prey as described above for the CRLF ( Potential for Direct Effects: Terrestrial-phase CRLF [Juveniles and Adults]) and for the SMHM (see “ Potential for Direct Effects” )
POTENTIAL FOR DIRECT EFFECTS

Direct Deposition on Forage Items: Mammalian RQ - Acute and chronic dose-based RQs exceed the Agency acute listed and chronic LOC in all modeled scenarios (N=20) for large mammals. Chronic dietary-based RQs
exceed the chronic LOC in all 20 modeled s cenarios for large mammals that feed on short grass, tall grass, and broadleaf plan ts/small insects (chronic dietary-based RQs for 13/20 scenarios exceed the LOC for large mammals consuming fruits/pods/seeds/large insects).

Temporal and Spatial Overlap - Temporal overlap between endosulfan app lication and all life stages of SJKF was
identified.

- A moderate amount of spatial overlap between SJKF occurrence and current (and potential future use) of endosulfan was identified ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS San Joaquin
kit fox ( Vulpes

macrotis

mutica ) LAA 1

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Birds and Mammals : - Acute and chronic RQ for birds and mamm als serving as prey to the SJKF exceed
listed acute and chronic LOCs as a result of direct deposition onto forage items and bioaccumulation in terrestrial prey as described above for the CRLF ( Potential for Direct Effects: Terrestrial-phase CRLF [Juveniles and Adults]) and for the SMHM (see “ Potential for Direct Effects” )



### 20Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

POTENTIAL FOR DIRECT EFFECTS Terrestrial Invertebrate RQs :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of BCB was
identified. - No spatial overlap identified at the County level based on current endosulfan use reported for California. If cultivated crop /orchard/vineyard uses are considered areas
of potentia l endosulfan use in the future, then a substantial amount of spatial overlap
can be observed relative to the total area of BCB occurrence sections. - When exposure of terrestrial insects via spray drift is considered, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source. - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase BCB exposure, particularly in areas of potential endosulfan use west of BCB occurrence sections in Santa Clara County ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS Bay checkerspot

butterfly ( Euphydryas
editha bayensis )

(BCB) LAA 1

-Although effects to terrestria l plants cannot be quantified due to the lack of data, aquatic non-vascular plants are not particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. - No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plant have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic animals. - No ecological incidents have been reported to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regul arly directly applied on or near a very wide variety of agricultural plants.
POTENTIAL FOR DIRECT EFFECTS Valley elderberry longhorn
beetle ( Desmocerus californicus dimorphus ) LAA 1
Terrestrial Invertebrate RQs :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan app lication and all life stages of VELB was
identified. - A small amount of spatial overlap identif ied at the County level based on current



### 21Table 1.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
endosulfan use reported for California. If cultivated crop/orchard/vineyard uses are
considered areas of potentia l endosulfan use in the future, then a moderate amount of spatial overlap can be observed relative to the total area of VELB occurrence sections ( Appendix E ). - When exposure of terrestrial insects via spray drift is considered, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase VELB exposure, particularly in ar eas of potential endosulfan use west of
VELB occurrence sections.
POTENTIAL FOR INDIRECT EFFECTS -Although effects to terrestria l plants cannot be quantified due to the lack of data, aquatic non-vascular plants are not particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. - No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plant have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic animals. - No ecological incidents have been reported to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regul arly directly applied on or near a very wide variety of agricultural plants.

1 No effect (NE); May affect, but no t likely to adversely affect (NLAA); Ma y affect, likely to adversely affect (LAA)



### Table 1.2 Effects Determination Summary for the Critical Habitat Impact Analysis Designated
Critical Habitat
for: Effects
Determination 1 Basis for Determination

CRLF May Affect -There is a potential for direct effects to the aquatic-phase CRLF and indirect effects via reduction of aquatic-phase prey items (aquatic invertebrates, fish, and aquatic-phase amphibians) as described in Table 1.1
above. - There is a potential for direct eff ects to the terrestrial-phase CRLF and
indirect effects via reduction of te rrestrial-phase prey items (mammals, amphibians, and terrestrial invertebrates) as described in Table 1.1 above.

CTS May Affect There is a potential for direct effect s to the CTF and indirect effects via reduction of aquatic-phase prey items (aquatic invertebrates and fish) as
described in Table 1.1 above. - There is a potential for direct effect s to the CTF and indirect effects via reduction of terrestrial-phase prey ite ms (terrestrial invertebrates) as
described in Table 1.1 above.

BCB NE 1 -Although effects to terrestrial plants ca nnot be quantified due to the lack of data, aquatic non-vascular plants are no t particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. -No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plan t have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use



### 22suggests that aquatic nonvascular plants are insensitive relative to aquatic
animals. - No ecological incidents have been repo rted to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regularly directly applied on or near a very wide variety of agricultural plants.

VELB NE 1 -Although effects to terrestrial plants ca nnot be quantified due to the lack of data, aquatic non-vascular plants are no t particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. -No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plan t have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic
animals. - No ecological incidents have been repo rted to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regularly directly applied on or near a very wide variety of agricultural plants.

1 No effect (NE)



### The Agency has determined that there is No E ffect to BCB and VELB designated critical habitat from the use of endosulfan. Although there were no reliable data to quan titatively evaluate the effects and the potential risks of endosulfan to te rrestrial plants, aquatic non-vascular plants are not particularly sensitive to endosulfan, endosul fan has a neural toxic mode of action, and no studies demonstrating significant adverse eff ects of endosulfan on growth, survival, or reproduction of any vascular aquatic or terrestr ial plants have been identified in the open literature. Furthermore, of the 83 ecological incidents repo rted to the Agency involving endosulfan, only one was associated with plants (unspecified plant damage) and its certainty index was only considered “possible.” Lastl y, a review of efficacy studies for endosulfan
indicates that adverse effect s on crops at registered app lication rates is not likely.

Based on the conclusions of this assessment, a formal consultation with the U. S. Fish and Wildlife Service under Section 7 of the Endange red Species Act should be initiated.

When evaluating the significance of this risk assessment’s direct/indire ct and habitat effects determinations, it is important to note that pestic ide exposures and predicted risks to the species and its resources (i.e., food and habi tat) are not expected to be uni form across the action area. In fact, given the assumptions of drift and downstr eam transport (i.e., attenuation with distance), pesticide exposure and associated risks to the spec ies and its resources are expected to decrease with increasing distance away from the treated fiel d or site of applicati on. Evaluation of the implication of this non-uniform distribution of ri sk to the species would require information and assessment techniques that are not currently avai lable. Examples of such information and methodology required for this type of an alysis would include the following:

• Enhanced information on the density a nd distribution of CRLF, SFGS, CTS, BCB, VELB, SMHM, and SJKF life stages within the action area and/or applicable designated critical habitat. This information would allow for quantitative extrapolation of the pres ent risk assessment’s predictions of
individual effects to the proportion of the population extant within geographical

23

### areas where those effects are predic ted. Furthermore, such population information would allow for a more comp rehensive evaluation of the significance of potential resource impairment to individuals of the assessed species.

• Quantitative information on prey base requirements for the assessed species. While existing information provides a prel iminary picture of the types of food sources utilized by the assessed spec ies, it does not establish minimal requirements to sustain healthy individua ls at varying life stages. Such
information could be used to establish bi ologically relevant thresholds of effects on the prey base, and ultimately establis h geographical limits to those effects. This information could be used together with the density data discussed above to
characterize the likelihood of a dverse effects to individuals.

• Information on population responses of prey base organisms to the pesticide. Currently, methodologies are limited to pr edicting exposures and likely levels of direct mortality, growth or reproduct ive impairment immediately following exposure to the pesticide. The degree to which repeated exposure events and the inherent demographic characte ristics 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 pesticid e exposure would allow for a more refined determination of the magnitude and durati on of resource impairment, and together with the information described above, a more complete prediction of effects to individual species and potential m odification to critical habitat.

24

# 2 Problem Formulation

Problem formulation provides a strategic framewor k for the risk assessment. By identifying the important components of the proble m, it focuses the assessment on the most relevant life history stages, habitat components, chemical properties, exposure routes, and en dpoints. 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 review ed 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 following Federally Threatened species:

• California Red-legged Frog (CRLF), Rana aurora draytonii,

• Bay Checkerspot Butterfly (BCB), Euphydryas editha bayensis,

• Valley Elderberry Longhorn Beetle (VELB), Desmocerus californicus dimorphus , and

• California Tiger Salamander (CTS), Ambystoma californiense,

and the following Federally Endangered species:

• San Francisco Garter Snake ( Thamnophis sirtalis tetrataenia ),

• San Joaquin Kit Fox ( Vulpes macrotis mutica ), and

• Salt Marsh Harvest Mouse ( Reithrodontomys raviventris )

These effects arise from FIFRA regulatory actio ns regarding use of endosulfan on tree crops (nuts, citrus, and other fruits), field crops (cotton, potatoes, and row crops), cucurbits, leafy vegetables (lettuce), fruiting vegetables (tom ato, strawberry and eggpl ant), and tree outdoor nurseries. In addition, this assessment evaluates whether use on these use sites is expected to result in effects to designated critical habitat for the CRLF CTS, BCB, and VELB. This ecological risk assessment has been prepared consistent with the settlement agreement in Center for Biological Diversity (CBD) vs. EPA et al . (Case No. 02-1580-JSW(JL)) which addresses the CRLF and was entered in Federal District Court for the Northern District of California on October 20, 2006.

This assessment also addresses the SFGS , SMHM, BCB, VELB, SJKF, and CTS for which endosulfan was alleged to be of concern in a separate suit ( Center for Biological Diversity (CBD) vs.

EPA et al . (Case No. 07-2794-JCS)).



### In this assessment, direct a nd indirect effects to the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and potential effects to designated cr itical habitat for the CRLF, CTS, BCB, and
VELB are evaluated in accordance with the methods described in the Agency’s Overview Document (U.S. EPA 2004). The effects determin ations for each listed sp ecies assessed is based on a weight-of-evidence method that relies h eavily on an evaluation of risks to each taxon
relevant to assess both dir ect and indirect effects to the listed species and the potential for effects to their designated critical habitat ( i.e ., a taxon-level approach). Sc reening level methods include use of standard models such as PRZM-EXAMS, T-REX, TerrPlant, AgDRIFT, and AGDISP, all of which are described at length in the Overvi ew Document. Additional refinements include:

251. 

### Use of T-HERPS model for estimating expos ure to terrestrial phase amphibians and reptiles

2. 

### Use of the KABAM model for estimating endosulfan accumulation in aquatic food webs and subsequent risks to terrestrial wildlife consuming aquatic prey

3. 

### Use of earthworm fugacity modeling to predict concentrations in terre strial food items for the SMHM, SJKF, and CTS.

Use of such information is consistent w ith the methodology described in the Overview Document (U.S. EPA 2004), whic h specifies that “the assess ment process may, on a case-bycase basis, incorporate additional methods, m odels, and lines of evidence that EPA finds technically appropriate for risk management obj ectives” (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 endosulfan is ba sed on an action area. The acti on area is the area directly or indirectly affected by the federal action, as indicated by the exceedence of the Agency’s Levels of Concern (LOCs). It is acknowledged that the action ar ea for a national-level FIFRA regulatory decision associated with a use of endosul fan may potentially involve numerous areas throughout the United States and its Territories. However, for th e purposes of this assessment,
attention will be focused on relevant sections of the action area includi ng those geographic areas associated with locations of the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and their designated critical habitat within the state of California. As part of the “effects determination,” one of the following three conclusions will be reac hed separately for each of the assessed species regarding the potential use of endosulfa n in accordance with current labels:

• “No effect”;

• “May affect, but not likely to adversely affect”; or

• “May affect and likely to adversely affect”.

The CRLF, BCB, CTS, and VELB have designated critical habitat asso ciated with them. Designated critical habitat identif ies specific areas that have the physical and biological features, (known as primary constituent elements or PCEs ) essential to the conservation of the listed species. A brief summary of PCEs for thes e species being assessed is as follows.

CRLF. The PCEs for CRLF are aquatic and upland areas where su itable breeding and non-breeding aquatic hab itat is located, inters persed with upland foraging and dispersal
habitat.

BCB. The PCEs for BCB include the presence of annual or perennial grasslands with little to no overstory and N-S or E-W slopes with a tilt of >7 degrees, areas of serpentinite
ultramafic rock or similar soils that support the primary larval host plant ( i.e ., dwarf plantain) and at least one of the species’ secondary host plants, the presence of adult nectar sources, aquatic feat ures that provide moisture during the spring drought, and the presence stable holes and cracks in the soil, and surface rock outcrops that provide shelter during the summer diapause.

26

### CTS. The PCEs for CTS include standing bodies of fresh water (e.g., ponds, vernal pools and dune ponds, and other ephemeral or permanent water bodies), barrier-free uplands adjacent to breeding ponds that contain small mammal burrows (used for habitat), and upland areas between breeding locations and areas with small mammal burrows that allow for dispersal among such sites

VELB. The PCEs for VELB include areas containi ng the host plant of this species [i.e., elderberry trees (Sambucus sp.)].

If the results of initial screening-level assessment methods show no direct or indirect effects (no LOC exceedances) upon individuals or upon the PCEs of the species’ designate d critical habitat,
a “no effect” determination is made for use of endosulfan as it relates to each species and its designated critical habitat. If, however, potential direct or indirect effects to individuals of the species are anticipated or effect s may impact the PCEs of the designated critical habitat, a preliminary “may affect” determination is ma de for the FIFRA regul atory action regarding
endosulfan.

If a determination is made that use of endosulfa n “may affect” a listed species or its designated critical habitat, additional information is consid ered to refine the poten tial for exposure and for effects to each species a nd other taxonomic groups upon which these species depend ( e.g., prey items). Additional information, including spat ial analysis (to determine the geographical proximity of the assessed species’ habitat and endosulfan use sites) and further evaluation of the potential impact of endosulfan on the PCEs is also used to determine whether effects to designated critical habitat may occur. Based on the refined information, the Agency uses the
best available information to di stinguish 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 assessed listed species and/or ha ve “no effect” on or “may affect” the PCEs of its designated critical habitat. This information is presen ted as part of the Ri sk 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 de signated critical habitat. Because endosulfan is expected to directly imp act living organisms within the action area (defined in Section 2.7 ), critical habitat analysis for endosulfan is limited in a practical sense to those PCEs of critical habitat that are biological or th at can be reasonably linked to biologically mediated processes ( i.e ., the biological resource requirement s for the listed species associat ed with the critical habitat or important physical aspects of the habitat that may be reasonabl y influenced through biological processes). Activities that ma y affect critical habitat are t hose that alter the PCEs and appreciably diminish the value of the habitat. Evaluation of actions rela ted to use of endosulfan that may alter the PCEs of the assessed species’ critical habitat form the basis of the critical habitat impact analysis. Designated critical is discussed further in Section 2.6

.

2.2 Scope

Endosulfan is mainly used as an agricultural inse cticide to control insect pests such as aphids, fruit worms, beetles, leafhoppers, moth larvae, and whiteflies. Endosulfa n is applied as liquid

27

### spray prepared from emulsifiasble concentrat e (EC) and wettable powder (WP) formulations using aircraft or ground equipment. The pesticide is mostly applied as foliar spray with single rates ranging from 0.5 to 2.5 lbs a.i/A at mini mum intervals ranging from 5 to 10 days and
maximum total rate from 0.5 to 3.0 lb a.i/season or year. The following uses are considered as part of the federal action evaluated in this assessment: nut trees (almonds, hazelnuts, and walnuts), non-bearing citrus trees, cole crops , fresh market sweet corn, cotton, pome fruits (apple, and pear), stone fruits (apricot, nectarine, peach, ch erry, , plum, and prune), leafy vegetables (lettuce, Brussels sp routs, and celery), cucurbits, ou tdoor nurseries for ornamentals and shade trees, potato, sweet potato, dry beans and peas, carrot, and fruiting vegetables (pepper, strawberry, eggplant, and tomatoes ). Non-agriculture is a minor us e as it is used impregnated in cattle ear tags.

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 know n as end-use labels) de scribe the formulation type ( e.g. , liquid or granular), acceptable methods of application, approved use sites, and any restrictions on how applications may be conducte d. Thus, the use or potential use of endosulfan in accordance with the approved product labels fo r California is “the action” relevant to this ecological risk assessment.

Although current registrations of endosulfan allow for use nati onwide, this ecological risk
assessment and effects determination addresses currently registered uses of endosulfan in portions of the action area that are reasonably assumed to be biol ogically relevant to the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and th eir designated critical habitat. Further discussion of the action area for the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and their critical habitat, if any, is provided in Section 2.7

.

The two isomers of endosulfan, alpha ( α ) and beta ( β ), degrade at different rates into a common degradate, the endosulfan sulfate. Although other de gradates such as endosulfan diol and ether form, expected quantities in the environment are lo w as they may form as a result of hydrolysis of spray drift reaching biologically active water bodies where the sulfate is expected to form instead. In this assessment, the highly persistent e ndosulfan sulfate is included with both isomers.
This is because endosulfan sulfat e is the major degradate forming in the soil system to which the major amount of the pesticide is applied. Additionally, endosulfan sulfate is highly persistent in the major compartments of the environment. Exposure was determined for both parents and the common endosulfan sulfate degrad ate using PRZM/EXAMS modeling.

The Agency does not routinely include, in its ri sk assessments, an evaluation of mixtures of active ingredients, either those mixtures of multip le active ingredients in product formulations or those in the applicator’s tank. In the case of the product formulat ions of active ingredients (that is, a registered product containing more than on e active ingredient), eac h active ingredient is subject to an individual risk assessment for regulatory decision regarding the active ingredient on a particular use site. If effect s data are available for a formulat ed product containing more than one active ingredient, they may be used qualitati vely or quantitatively in accordance with the Agency’s Overview Document and the Services’ Evaluation Memorandum (U.S., EPA 2004; USFWS/NMFS 2004).

28

### Endosulfan does not have any registered products that contain multiple active ingredients.

2.3 Previous Assessments

In February, 2002, the USEPA completed an Environmental Fate and Ecological Risk Assessment of endosulfan in support of the re-reg istration eligibility de cision for endosulfan use on both food and non food crops (USEPA, 2002; DP Barcode D238673). Based on a screening level assessment for terrestrial impacts and a refined assessment for aquatic impacts, it was concluded that endosulfan (maximum application rate of 3 lb a.i./A) was lik ely to result in acute
and chronic risk to both terrestri al and aquatic organisms. Based on the tomato crop scenario that yielded the largest EECs, acute and chronic RQ values ranged from about 23 and 44 for freshwater fish, respectively, to about 190 and 490 for estuarine/marine fish, respectively. Acute and chronic RQ values for invertebrates range d from approximately3.3 and 93 for freshwater and from 42 to 130 for estuarine/marine fish, respectively. Monitoring da ta reported in the assessment demonstrated widespread contaminati on of surface water and ecological incident data indicated that the use pattern of endosulfan repr esented a substantial risk of mortality for nontarget aquatic species. Based on the 2002 Environmental Fate and Ecological Risk Assessment RQs for birds and mammals exceeded the Agency ’s acute and chronic risk LOCs and ranged up
to a maximum of 2.7 for birds and 40 for mammals.

The refined aquatic risk assessment used proba bilistic exposure assessment techniques and was based on actual reported applica tion rates in California coupled w ith a 300-ft spray drift buffer. The refined assessment concluded that on sites pr one to runoff within the endosulfan use area, mortality to non-target fish is probable in any given year. Furthermore, based on “nonconservative” assumptions (i.e., “typical” applic ation rates and a 300-foot spray drift buffer),
EFED concluded that the modeled endosulfan use rates on 88% of the crops modeled would exceed acute high risk LOCs more than 99% of the time

. The assessment’s conclusions were supported by incident data indicating multiple fish kill incidents attributab le to endosulfan use are reported each year. While repop ulation of aquatic communities was considered likely in the assessment (via migration from unaffected areas), the intermediate effect on food chains was
considered uncertain.

In 2007, USEPA published an addendum to the 2002 environmental fate and ecological risk assessment in order to evaluate the potential im pact of new information related to endosulfan toxicity, bioaccumulation, monitoring and tran sport, and ecological incidence (USEPA 2007; D346213). A number of aspects of the 2007 addendum differed from the previous assessment in
2002:

• Aquatic exposure modeling considered both th e parent isomers and the primary degradate of concern (endosulfan sulfate)

• A review of new monitoring data including the long-range transport of endosulfan was
conducted

• Bioaccumulation potential of endosulfan in aquatic organisms was evaluated using empirical data and a food web model

• New data on the toxicity of endosulfan sulfate was included

• Risk quotients were based on combined e xposure to parent and degradate compounds.

29

### Risk quotient (RQ) predicted for aquatic organisms resulting from water column exposure to
endosulfan were about 20% to 40% higher in the 2007 addendum co mpared to the 2002 ERA.
This increase reflected the addition of endosul fan sulfate to the exposure modeling and data indicating it is of similar acute t oxicity to the parent isomers ( α and β ). Based on the tomato crop scenario that yielded the larges t EECs, acute and chronic RQ va lues ranged from about 30 to 60 for freshwater fish, respectively (compared to 23 and 44 from the 2002 ERA) to about 230 and 680 for estuarine/marine fish, respectively (compared to 190 and 490 from the 2002 ERA). Acute and chronic RQ values for invertebrates ranged from approximately 4 to 130 for freshwater (compared to 3.3 and 93 from the 2002 ERA) and from 50 to 190 for estuarine/marine (compared to 42 to 130 from the 2002 ERA), respectively. Findings from ecological incidents generally supported the findi ngs of endosulfan risk to fish and invertebrates.

Risks to freshwater and estuarine/marine inve rtebrates resulting from sediment exposure to endosulfan are evident from the integration of exposure and effect characterization. The RQ values for sediment-dwelling invertebrates range form 0.9 to 2.8 depending on species. These RQ values are based on predicted total endosul fan residues compared to endosulfan sulfate toxicity values, which assumes similar toxici ty of endosulfan sulfate and total endosulfan
residues.

Based on preliminary results from an aquati c food web bioaccumulation model, risks to piscivorous wildlife appeared relatively modest with mean predicted acute RQ values exceeding the Agency acute LOC of 0.1 for one of eight species modeled (0.15 for river otter) and 90 th 

### percentile estimates exceeding the LOC for th ree of eight species modeled (0.18, 0.39, 0.20 for mink, river otter and belted kingfisher, respectiv ely). Predicted chronic RQ values did not exceed the Agency LOC for any of the eight species modeled.

Risks to non-target terrestrial wildlife did not change from th e 2002 ERA as a result of this addendum, because the currently available terrestrial exposure model could not address total residue exposure. Based on th e 2002 ERA, RQs for birds and ma mmals exceeded the Agency’s acute and chronic risk LOCs and range up to a maximum of 2.7 for birds and 40 for mammals.

In summary, the 2007 Addendum concluded there is a concordance of evidence that endosulfan is undergoing long-range transport and has moved to sites distant from use areas. Furthermore, the sulfate degradate was considered persistent and a significant source for endosulfan to enter aquatic and terrestrial food chains. Endosulfan wa s not expected to biomagnify appreciably in aquatic food webs (i.e., increasing concentrations with increasing trophic level), although it was
found that endosulfan can bioaccumulate substa ntially, with BCFs ranging from approximately 1,000 to 3,000 L/kg w.w. Risks to both aquatic and te rrestrial animals were identified using the latest information available. The Agency is currently responding to public comments received on
the 2007 Addendum.

2.4 Stressor Source and Distribution

This assessment considers the stressor to c onsist of multiple compounds, namely, endosulfan alpha, endosulfan beta and their common degradate endosulfan sulfate. The chemical name of endosulfan is 6,7,8,10,10-hexachloro-1,5,51,6,9,9a-hexahydro-6,9-methano-2,4,3-

30

### benzadioxathiepin 3-oxide. Endosulfan has two stereo-isomers, endosulfan alpha and beta ( α and β -endosulfan). According to the agricu ltural label, the maximum amount of α is 70% and β
is 30%. Figure 2.1 provides the structures of α . and β -endosulfan and major transformation products.

α -endosulfan (959-98-8) β -endosulfan (3213-65-9) Endosulfan Sulfate (1031-07-8)
The Multi-Chemical Stre ssor of Endosulfan

Endosulfan Diol (2157-19-9) Endosulfan Eth er (3369-52-6) Endosulfan Lactone (3868-612-9) Other Degradates of Endosulfan Figure 2.1 Chemical structures of endosulfan and related compounds



### The source of the stressor is foliar applica tion of endosulfan formul ated products including wettable powders (WP) and emulsifiable concen trates (EC) by air, ground and airblast application methods. In an agri cultural setting, major quantities of the app lied pesticide active ingredient reach target foliage and eventually end-up in the so il system. Smaller quantities of the applied pesticide reach nearby field or water bodies initially by drift and followed by runoff/erosion and by volatilization. Bi ologically mediated transformation of α and β -endosulfan is expected to occur in the soil system producing endosulfan sulfate (maximum levels > 52%), a common degradate of toxicological concern. En dosulfan sulfate is added to parent(s) as a stressor because it is a major toxic and persistent soil transfor mation product. In contrast, endosulfan diol is not included as a component of the stressor because it is less toxic and expected to form in biologically inactive neutra l and alkaline systems. Endosulfan diol was a major transformation product in sterile aqueous media (maximum levels > 82%) and was only a

31

### minor transformation product in aerobic soil syst ems in the laboratory and the field (maximum levels <10 %) (USEPA, 2002; DP Barcode D238673).

For the purpose of this assessment, the term “e ndosulfan” refers to th e technical grade active ingredient (TGAI) unless otherwis e indicated. The term “total endosulfan” or “endosulfans”
refers to the combination of α –endosulfan, β -endosulfan and endosulfan sulfate unless
otherwise noted.

2.4.1 Environmental Fate Properties

The physiochemical properties of the multi-chemical stressor are summarized in Table 2.1 . Fateand transport data for endosulfan isomers and common degradate endosulfan sulfate (the multichemical stressor) are summarized in Table 2.2

. Major and minor degradates detected in submitted environmental fate and transport studies are also included in the same Table 2.2

.

Table 2.1 Physiochemical properties of the multi-chemical stressor

Property α -endosulfan β -endosulfan Endosulfan sulfate

Formula C 9 H 6 Cl 6 O 3 S C 9 H 6 Cl 6 O 3 S C 9 H 6 Cl 6 SO 4 Molecular Weight 406.9 g/mole 406.9 g/mole 422.9 g/mole

CAS Number 959-98-8 33213-65-9 1031-07-8
Water Solubility 530 μ g/L 280 μ g/L 330 μ g/L
Vapor Pressure 1

( torr @ 25 o C) 4.6x10 -5 ; 1.5x10 -5 & 3.0x10 -6 2.4x10 -5 ; 6.9 & 7.2 x 10 -7 9.75x10 -6

Henry’s Law Constant 2


### ( atm-m 3 mol -1 @ 25 o C) 3.03x10 -6 1.38x10 -6 1.64x10 -5

Log K
aw (air/water) 3 -3.56 -4.75 -4.78 Log K
ow (octanol/water)

3 Corresponds to K

ow of: 4.93 95,499 4.78 60,256 3.71 5,129
Log K
oa 3 6.41 & 8.64 6.41 & 8.64 8.45 & No value

1 Vapor pressure for α and β -endosulfan (MRIDs 414215-01 and 400606-01) and for endosulfan sulfate from: Hinckley et al (1990) 2

2 All three values were calculated from the 1 st vapor pressure values above (in Bold) using molecular weight, solubility &

25 o C temperature
3 Source of data for partitioning coefficients: Log K

aw and K

ow as reported (Schenker et al, 2005) 3 while Log K

oa 

### is estimated by EPI Suite v4.0 4 ; 1 st value= EPI Suite estimate & 2 nd value= from EPI suite database

2 Daniel A. Hinckley, Terry F. Bidleman, William T. Fore man, Jack R. Tuschall. 199 0. Determination of vapor pressure for non-polar and semi-polar organic compounds from gas chromatography retention data J. Chem. Eng.

Data , 1990, 35 (3), pp 232–237

3 Schenker, U., MacLeod, M., Scheringer, M., Hungerbuhle r K., 2005. Improving data quality for environmental fate models: A least-square adjustment procedure for harmonizing physiochemical properties of organic compounds. Environmental Science & Technology 39, 8434-8441.

4 The Estimation Program s Interface EPI Suite: http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm



### 32

### Table 2.2 Summary of fate and transport prop erties for endosulfan isomers and sulfate

Study Value (units) Major & Minor Degradates Reference & Study Status *

Hydrolysis t1⁄2 @ pH 5: stable (>200 days) for both α and β t1⁄2 @ pH 7: 19 days for α ;11 days for β endosulfan sulfate: 184 days ** Major: Endosulfan diol 414129-01(A) for only pH 5 and 7

Aqueous Photolysis Stable, based on absorption spectrum None reported Registrant Data

Soil Photolysis Stable Minor: Endosulfan diol 414307-01 (A)

Aerobic Soil
Metabolism (Five soils) α -endosulfan: t1⁄2 35-67 days; 90th %= 57 days β -endosulfan: 104-265 days,; 90th %=208 days
endosulfan sulfate: Shows no clear decline
pattern Major: Endosulfan Sulfate
Minor: Endosulfan diol &
lactone 438128-01 (S)

Anaerobic Soil
Metabolism (Two soils, Two phase study) α -endosulfan: 105 & 124 days; 90th %=115 days β -endosulfan: 136 &161 days; 90th %=149 days endosulfan sulfate: 120 & 165 days; 90th %=143 days All calculated from the anaerobic phase of the experiment Major: Endosulfan Sulfate Formed during the aerobic phase
Minor: Endosulfan diol &
lactone 414129-04 (A)

Organic Carbon based Adsorption Coefficient (Koc) α -endosulfan: Koc 10,600 ml/g (Average for 4 soils) β -endosulfan: Koc 13,500 ml/g (Average for 4 soils) endosulfan sulfate & diol: Qualitatively, when compared to parents sulfate is similar or slightly more mobile while diol is substantially more mobile Not Applicable 414129-06 (S)

414129-05 (U)

No aerobic aquatic metabolism study wa s submitted; Submitted anaerobic aquatic metabolism study was Un-acceptable 449178-01 (U)

Terrestrial Field Dissipation α -endosulfan: t1⁄2 46 days (GA tomato), 70 days (CA cotton), and 6-11 days (CA cotton) β -endosulfan: t1⁄2 90 days (GA tomato), 103 days (CA cotton) and 19-63 days (CA cotton) Important Note: t1/2 in soil surface layer, encompassing movement as well as degradation Endosulfan-sulfate and
endosulfan-diol. The sulfate was dominant and appeared to be more persistent 413097-02 (A) 414686-01 (A) 430697-01 (A)

Accumulation in Nontarget Aquatic Organisms 600x in mussels with depuration t1⁄2 of 34 hr 2,429x for edible tissue and 2,755x for whole body of mullet with depuration within
48 hr Not Applicable 05003053 (A)

05005824 (A)

* Reference Numbers indicated are MRID or Access Numbers, Study Status: A= Acceptable; S= Supplemental and



### 33Study Value (units) Reference & Major & Minor Degradates Study Status *

U=Unacceptable ** An Extrapolated Hydrolysis at pH 7 value reported by Becker et al (2008) 5 From Guerin & Kennedy 1992



### The physiochemical data for endosulfan isomers a nd sulfate indicate that the three chemicals are practically insoluble in water. Vapor pressure and Henry’s law constant values for the three chemicals suggest that volatility is important in the dissipati on of the stressor. Endosulfan isomers and common degradate can be considered as semi-volatile compounds and can readily partition into air in measurable amounts as indicated by their ai r/water partition coefficients (from -4.78 to -3.56). Air/octano l and octanol/water coefficients suggest the three chemicals have high potential for bio-accumulation in aqua tic and terrestrial organisms, respectively ( Table
2.1 ).

Based on laboratory data, th e two biologically-active α - and - β stereo isomers of endosulfan differ in physiochemical and fate properties ( Table 2.2 ). The - β isomer is generally more persistent and the α -isomer is more volatile. In sterile conditions, α - and - β isomers are highly persistent in aqueous acid c onditions (t1⁄2>200 days) but highly vulnerable to hydrolysis in aqueous neutral conditions (t1⁄2= 11 and 19 days for α - and – β -endosulfan, respectivelly) producing a major degradate, the endosulfan di ol. Abiotic transfor mation by photolysis in aqueous media or on soil is not important. Both α - and - β endosulfan showed no significant absorption peaks in the visible light region of the spectra (290-800 nm). Additionally, the isomers had a similar degradation profile in soil exposed to light or kept in a dark control.

In contrast to abiotic transforma tion, biotic mediated oxidation in the soil system appears to be the dominant pathway for degradation of both endos ulfan isomers into endosulfan sulfate. In several aerobic soil studies, endosulfan isomers de graded into endosulfan su lfate with half-lives ranging from one to two months for α -endosulfan and from three to nine months for β

- endosulfan. Persistence of endosulfan appears to increase under anaer obic conditions. In two anaerobic soil metabolism studies, α - and β -endosulfan degraded with half-lives ranging from 105 to 124 days for α -endosulfan and 136 to 161 days for β -endosulfan. Endosulfan sulfate was the major degradate formed during the aerobic phas e of the study then degr aded with a half-life of 120 to 165 days.

In field dissipation studies, endosulfan persisted in the surface soil for weeks to months after application. Field dissipation ra tes capture a combination of de gradation, transport, and uptake processes whereas laboratory studies capture onl y degradation processes. Therefore, field dissipation rates can only be compared to laborato ry rates when these other transport and uptake processes are taken into account.

The major transformation products found in fate studi es are endosulfan diol (hydrolysis in sterile conditions) and endosulfan sulfate (soil metabolis m). Another minor transformation product is endosulfan lactone which was detected at 4-6% in the anaerobic soil system . It is noted that all

5 L. Becker, U. Schenker and M. Scheringer. 2008. Overall persistence and long range transport potential of endosulfan and its transformation products . Swiss Institute of Technology, ETH Zurich, Switzerland



### 34

### three degradation products have backbone structure of the parent compounds ( Figure 2.1 ).

When considering how to account for degradates, th e two major degradates were considered; that
is endosulfan sulfate and endosulfan diol. Endosul fan sulfate was identified for inclusion as a component of the stressor for the following reasons:

(1) Endosulfan sulfate forms by oxidation in the aerobic soil system (maximum levels > 52% of the applied). Only minor amount s of endosulfan diol and lactone ( < 10%) are formed in the aerobic soil system. Also, the sulfate is expected to be more persistent than its parents in the aerobic soil system. In aer obic soil studies, endosulfan sulfate was the major persistent degradate forming from α - and β -endosulfan;

(2) Endosulfan diol was reported to be less toxi c than parent or endosulfan sulfate (Verma et

a l 2006, siddique et al 2003, and others 6 

### ). The persistent or ganic pollutants review committee stated “Endosulfan is a very toxic ch emical for nearly all kind of organisms. Metabolism occurs rapidly, but the oxidised metabolite endosulfan sulfate shows an acute toxicity similar to that of the parent co mpound. In contrast, endosulfan-diol, which is another metabolite of endosulfan, is found subs tantially less toxic to fish by about three orders of magnitude” 7



### (3) The bulk of applied pesticide reaches the soil system with relatively small amounts reaching water bodies by drift (estimated to be 2.4% with a 300 ft. buffer).

(4) Endosulfan diol is assumed to form from pa rent isomers reaching water by drift only in abiotic conditions. As most environmentally re levant water bodies are biologically active, endosulfan diol is not expected to form in subs tantial amounts in natural aquatic systems. However, no acceptable aerobic or anaerobic aquatic water sediment systems are available to confirm this assumption.

Endosulfan isomers can be considered as hardly mobile in the soil syst em. The two chemical species have relatively high affinity to soil particles (K
oc 

### ranges from 10,600 to 13,500 ml/g) ( Table 2.2 ). This property causes chemicals to partiti on into the soil and reduces readiness for leaching into ground water. Endosulfan sulfate appear to be similar to parent isomers in mobility although the endosulfan diol is substantially more mobile ( Table 2.2 ).

Laboratory measured K

ow 

### values (95,499 for α –endosulfan, 60,256 for β -endosulfan, and 5,129 for endosulfan sulfate) suggest a relatively high po tential to bioconcentrate in aquatic organisms such as fish. However, supplemental studies suggest that endosulfan isomers did not bioconcentrate at the high levels suggested by K

ow 

### ( Table 2.1 ). In one study conducted with α -

6 http://umbbd.msi.umn.edu/end/end_map.html http://www.ces.clemson.ed u/ecl/caseStudy/case2.pdf

7 http://www.unon.org/confss/doc/unep/pops/P OPRC_04/POPRC_4_14/K0841692%20POPRC-4-14.pdf Persistent Organic Pollutants Review Committee; Fourth meeting; Geneva, 13–17 October 2008; Item 7 (a) of the provisional agenda: Consideration of chemicals newly proposed for inclusion in nnexes A, B or C of the
Convention: endosulfan



### 35

### endosulfan on mussels, the bio-c oncentration factor was approximately 600X, with a depuration half-life of 34 hours (Acc. No. 05003053). In anothe r study, conducted on striped mullet, the bioconcentration factor was 2,400X for combined is omers in edible tissues (Acc. No. 05005824). In this study, endosulfan depurated after 48 hours ( Table 2.2 ). Tissue analysis in one study revealed the presence of e ndosulfan sulfate rather than α - and β -endosulfan, suggesting the potential accumulation of this degradate.

2.4.2 Environmental Transport Mechanisms

Potential transport mechanisms or routes of pesticide exposure include surface water runoff/erosion, spray drift, and secondary drift of volatilized or soil- bound residues leading to deposition onto nearby or more distant ecosystems. In addition, pesticides can reach shallow ground water through leaching when the chemical is characterized by relative high mobility and moderate persistence. Low mobility pesticides may also leach into ground water if they can persist long enough for such movement to occur. For endosulfan, surface water run-off /erosion, drift, and atmospheric transport are expect ed to be the major routes of exposure.

A number of studies have documented atmosphe ric transport and re-dep osition of pesticides from the Central Valley to the Sierra Neva da Mountains (Fellers et al., 2004, Sparling et al

., 2001, LeNoir et al ., 1999, and McConnell et al ., 1998). Prevailing winds blow across the Central Valley eastward to the Sierra Nevada Mountains, trans porting airborne industrial and agricultural pollutants into the Sierra Nevada ecosystems (Fellers et al., 2004, LeNoir et al., 1999, and McConnell et al., 1998). Several sections of the range and/or critical habitat for the listed species being evaluated in this assessment are located east of areas of potential endosulfan use ( Appendix E) . The magnitude of transport via sec ondary drift depends on the ability of
endosulfan to be mobilized into air and its ev entual removal through wet and dry deposition of gases/particles and photochemical reactions in the atmosphere. Therefore, physicochemical properties of endosulfan that describe its poten tial to enter the air from water or soil ( e.g., Henry’s Law constant and vapor pr essure), pesticide use data, modeled estimated concentrations in water and air, and available air monitoring data from the Central Valley and the Sierra Nevada are considered in evaluating the potential for at mospheric transport of endosulfan to locations where it could impact the listed species included in this assessment.

In general, deposition of drifting or volatilized pe sticides is expected to be greatest close to the site of application. Computer models of sp ray drift (AgDRIFT and/or AGDISP) are used to determine potential exposures to aquatic and terrestrial organisms via spray drift.

The distance of potential impact away from the use sites is determined by the distance required to fall below the LOC for the taxonomic groups with the highest RQ to LOC ratio (for endosulfan, this consists of terrest rial insects for transport via spra y drift and freshwater fish for transport via downstream flow).

2.4.3 Mechanism of Action

Endosulfan is a dioxathiepin (broadly classified as a chlorinated hydrocarbon) insecticide and acaricide. Technical endosulfan is made up of a mixture of two molecular forms (stereo isomers) of endosulfan – the alpha ( α ) and beta ( β ) isomers. This arylheterocycle acts as a poison to a

36

### wide variety of insects and mites on contact th rough blockage of GABA- (gamma amino butyric acid) gated chloride channels, which in turn indu ces the uptake of chloride ions by neurons. The blockage of the GABA neurotransmitter activity by cyclodiene insecticides like endosulfan results in only partial repolarization of the neur on and a state of uncontrolled excitation (Klassen & Watkins, 1999). Stimulation of the central ne rvous system is the major characteristic of endosulfan poisoning (Ecobichon 1991).

Dissociation studies (Rauh et al. 1997) showed that dieldrin, ke toendrin, toxaphene, heptachlor epoxide and α

- and β -endosulfan competitively bind with GABA receptors. Additionally, animal data indicate that toxicity may also be influenced by species and by level of protein in the diet; rats which have been deprived of protein are near ly twice as susceptible to the toxic effects of
endosulfan. Solvent and/or emulsifiers used with endosulfan in fo rmulated products may influence its absorption into the system via a ll routes: technical endos ulfan is slowly and incompletely absorbed into the body whereas ab sorption is more rapid in the presence of alcohols, oils, and emulsifiers (Gupta and Gupta 1979).

2.4.4 Use Characterization

Current labeled use

(a) Nationally

Current registered uses of endosulfan include a wide variety of food crops, non-food crops and ornamentals. The list includes nut trees (almond s, hazelnuts, and walnuts), non-bearing citrus trees, cole crops (including Kohlra bi) , fresh market sweet corn, cotton, pome fruits (apple, and pear), stone fruits (apricot, nectarine, peach, ch erry, plum, and prune), leafy vegetables (lettuce, Brussels sprouts), cele ry, cucurbits, outdoor nurseries for ornamentals and shade trees, potato, sweet potato, dry beans and peas, carrot, and frui ting vegetables (pepper, strawberry, eggplant, and tomatoes), tobacco (field, seed/plant beds), pi neapple (fresh market only), and blueberry. No residential or public health uses are labeled for endosulfan although impregnated ear-tags are
labeled for use on cattle.

(b) California (CA)

Labeled endosulfan uses that could potentially be used in California were analyzed in detail
because it is the critical firs t step in evaluating the federa l action. The current label for endosulfan represents the FIFRA regulatory action; therefore, labeled us e and application rates specified on the label form the basis of this a ssessment. A summary of these labeled uses for
endosulfan is included in Table 2.3 . Application parameters included in Table 2.3 cover the most conservative application parameters and method of application for labeled crops.

Table 2.3 Endosulfan labeled uses assessed for California (No single application rate over 1.5 lbs except for orchard crops and strawberries)

Application: Maximum Rate, Number and Total 2

Use (Application Method) 1** Single Rate (lb a.i./A) Number Total/Season Or

Year Minimum Application Intervals (day) 3

Almond, Hazelnut & Walnut 2.00 1 2.00 NA



### 37Table 2.3 Endosulfan labeled uses assessed for California (No single application rate over 1.5 lbs except for orchard crops and strawberries)

Application: Maximum Rate, Number and Total 2 Minimum Application Intervals Single Rate (lb Total/Season Or Use (Application Method) 1** a.i./A) Number Year (day) 3

2.50 1 2.50 NA

Citrus, non-bearing trees only 0.50+2.00 2 2.50 10 Broccoli, Cabbage, Chinese cabbage &
Cauliflower 1.00 2 2.00 7

Collards, Kale & Mustard Green 0.75 1 0.75 NA

Corn, Sweet for fresh market only 1.50 1 1.50 NA

1.00 2 2.00 7

Cotton (Ground) 0.50+1.50 2 2.00 7

Cotton (Aerial) 0.75 2 1.50 7

2.50 1 2.50 10

Apple 0.50+0.75+1.25 3 2.50 10

2.50 1 2.50 10 Apricot, Nectarine, Peach, Cherry, Pear,
Plum & Prune 0.50+2.00 2 2.50 10 Lettuce (head & Leaf) 4 & Brussels Sprouts 1.00 2 2.00 5

1.00 2 2.00 7

Cucumber, Melons, Pumpkin & Squash 5 0.50+0.50+1.0 3 2.00 7

0.50 1 0.50 NA

Eggplant 0.25 2 0.50 7

Ornamentals or shade Trees 6 0.50 6 3.00 10

1.00 2 2.00 5

Potato 0.50 4 2.00 5

Sweet Potato 0.50 3 1.50 5

Dry Beans, Dry Peas & Pepper 1.00 2 2.00 5

Carrot 1.00 1 1.00 NA

1.00 1 1.00 NA

Celery 0.5 2 1.00 5



### 38Table 2.3 Endosulfan labeled uses assessed for California (No single application rate over 1.5 lbs except for orchard crops and strawberries)

Application: Maximum Rate, Number and Total 2 Minimum Application Intervals Single Rate (lb Total/Season Or Use (Application Method) 1** a.i./A) Number Year (day) 3

2.00 1 2.00 NA

Strawberry 1.00 2 2.00 15

1.00 2 2.00 7

Tomato 0.5 4 2.00 7

1 Unless specified, the application method can be any of aerial or ground or airb last for tree crops only

2 In some cases, the number of applicati ons was adjusted in order to always in clude the maximum single rate and at the same time abide by the maximum total applied/season or year. An additional application entry was included for specific crops to abide by both the maximum number of applications and the maximum total applied/season or year. Total lbs a.i applied/Acre was specified to be either per season or pe r year, therefore, multiple cropping may occur as follows: Two

crops for Broccoli & Lettuce; Three crops for Cabbage, Chinese cabbage, Cau liflower, Collards, Mustard Green & Sweet Corn; and Four crops for Kale.

3 Application Intervals in italic were assumed as it was not specified on the Label. Assignments were based on previous assessments (EPA, 2002) or on similarities in crops and target pest(s); NA= Not Applicable

4 Lettuce including: head, leaf (black seeded Simpson, an d salad. Do not exceed 2 applications after thinning)

5 Squash: including summer, winter, and Hubbard

6 Outdoor Nursery for Shade trees and Shrubs only ** Although pineapple was one of the crops labeled for CA, the use was not considered as pineapple is not grown in CA.



### Data for Table 2.3 were obtained from the newly revised and USEPA approved 2007-2008
labels which included the follo wing 2002 RED mitigation measures:

(1) Deletion of use on succulent beans, succu lent peas, spinach, grapes, and pecans; (2) Reduction of maximum seasonal app lication rates (lbs./a.i./A ): (a) From 3.0 to 2.5 lbs for pome fruit, stone fruit, and citrus; (b) From 3.0 to 2.0 lbs for melons, cucurb its, lettuce, tomatoes, sweet potatoes, cotton (ground), broccoli, cauliflower, cabbage, kohlra bi, brussels sprouts, strawberries, filberts, walnuts, almond s, macadamia nuts, peppers, eggplant, potatoes, carrots, dry beans, dry peas, and tobacco; (c) From 3.0 to 1.5 lbs for sweet corn, cotton (aerial) and blueberries; (d) From 3.0 to 1.0 lb for celery. (3) Requirement of 100 ft. spray buffer for ground applications between a treated area and water bodies; (4) Requirement of 30 ft. maintained vegetative buffer strip between a treated area and water bodies; (5) Requirement of all products to be Restricted Use; (6) Restriction of use on: (a) Cotton to AZ, CA, NM, OK and TX only; and (b) Tobacco to IN, KY, OH, PA, TN and WV only.

Similar mitigation measures apply for California with the following exceptions:

39

### (1) Maximum seasonal rates in lbs a.i. /A/season were reduced to 1.5 lbs for sweet corn, 1.0 lb for carrots and 0.5 lb for eggplant; (2) Deletion of use on tobacco, blueberries, and kohlrabi.

These measures were included in Table 2.3 above. The complete anal ysis of labeled use along with registration numbers is included in Appendix A along with use verification memo of SRRD and RD. No 24(c) or sections 18s are relevant to California.

Finally, slightly different appli cation restrictions are included fo r use in CA to further reduce drift and protect surface waters. For example, at the national level buffer distance is 300 ft for aerial application and 100 ft for ground applicati on while the distance in CA is 300 ft for both aerial and ground application. A 30 ft vegetative buffer is also included in CA. Other
restrictions also include: no zzle height maximum of 4 ft above ground or crop canopy; a maximum wind speed 10 mph; and the use fine-medium or coarse spray ASAE 573.

Endosulfan is also labeled for use in ear tags for cattle. The ear tag is impregnated with endosulfan (30% a.i.) and is to be attached to animal ears ( Table 2.4 ).

Table 2.4 California labeled non-crop use for endosulfan

Use Pattern* Application Information
Beef Range Feeder Cattle (Meat, All or unspecified) Dairy Cattle (Lactating or Unspecified) Two ear tags per animal (0.198 lb a.i./A nimal) for fly control (e.g., horn fly)

* Avenger insecticide cattle ear tag (CA registra tion number 61483- 65-AA; November, 05, 2007) 8



### In this assessment, the potential use of endosul fan in cattle ear tags wi thin California is not
evaluated. Most of the endosulfan released from cattle ear tags is expected to volatilize, adsorb
to the cow and/or wash off into the soil. Given that this particular formula tion is not expected to be subject to extensive transport, exposure is expected to be deminimus and was not quantitatively assessed.

8 

### http://www.cdpr.ca.gov/cgi-bin/label/labrep.pl

40

### Historical usage

(a) Nationally

National data show a decline in the estimated endos ulfan usage. USGS data show a decreased in total usage from 1.79 million lbs in 1992 to 1.52 million lbs in 1997 and 0.79 million lbs in
2002 9 

### . Reported average annual endosulfan usag e was estimated at approximately 1.38 million lbs, based on available pesticide survey data for the years from 1990 to 1999 (EPA, 2002). A summary of data, from both sources, is included in Table 2.5 showing the distribution of lbs used for various crops and in Figure 2.2 showing the general spat ial distribution of usage through out the United States.

Table 2.5 Top use patterns for endosulfan for selected years from 1990 to 2002

% of Total for the Year(s) Crop 1992 1997 1990-1999* 2002

Cotton 25% 29% 21% 20% Fruits (apples & pears) 17% 12% 8% 14%

Potatoes 10% 11% 9% 11%

Tomatoes 8% 3% 4% 11%

Pecan 7% 3% 4% ** Grapes 7%   **  Cucurbits: cantaloupe, squash, watermelon & cucumber 6% 8% 6% 8%

Tobacco *** 11% 5% 7%

Lettuce 5% 3% 4% 4%

Alfalfa *** 3% *** **

Green beans *** *** *** 4%

Horticulture *** *** 4% ***

Others** 15% 17% 35% 21%

Totals in millions of lbs a.i 1.79 1.52 1.38 0.79

* Average for the years from 1990 to 1999 Others** = sum of all uses donated as “***”



### Usage data indicate that the top three use patterns were for cotton, certain fruits, and potatoes during the period from 1992 to 2002. The 4 th 

### and 5 th 

### use patterns include combinations of tomatoes, tobacco, and cucurbits or pecan, gr apes, and cucurbits. As suggested by the 2002 RED, observed changes in the use pattern may be related to shifts in use in response to the dynamics of the agricultural system (e.g., changes in crop area), pest populations (e.g., pest outbreaks) changes in pesticide availability (e.g., new pesticides register ed and restrictions on old pesticides), and the variabil ity in using data from various information sources (EPA, 2002).

9 Sources of Data for 1992, 1997: URLs



### 41Average annual use of active ingredient (pounds per square mile of agricultural land in county

1992 1997 2002

No estimate use No estimated use No estimated use

0.001 to 0.007 0.001 to 0.006 0.001 to 0.005
0.008 to 0.028 0.007 to 0.027 0.006 to 0.018
0.029 to 0.108 0.028 to 0.105 0.019 to 0.064
0.109 to 0.454 0.106 to 0.480 0.065 to 0.259

≥ 0.455 ≥ 0.455 ≥ 0.260 

### 2002

1997 1992

Figure 2.2 Endosulfan Use in Tota l Pounds per County (not e vlues are different in chosen categories)



### (a) California

The Agency’s Biological and Economic Analysis Di vision (BEAD) provided an analysis of both national- and county-level usage information usin g state-level usage data obtained from USDANASS 10 

### , Doane 11 

### and the California’s Department of Pesticide Regulation Pesticide Use Reporting (CDPR PUR) database 12 

### . CDPR PUR is considered a more comprehensive source of

10 United States Depart of Agriculture (USDA), Nationa l Agricultural Statistics Service (NASS) Chemical Use Reports provide summary pesticide usage statistics for select agricultural use sites by chemical, crop and state. See http://www.usda.gov/nass/pubs/estindx1.htm#agchem

. 11 www.doane.com (the full dataset is not provided due to its proprietary nature)

12 The California Department of Pesticide Regulation’s Pesticide Use Reporting database provides a census of pesticide applications in the state. See http://www.cdpr.ca.gov/docs/pur/purmain.htm.



### 42

### usage data than the USDA-NASS or EPA proprietary databases, and thus the usage data reported for endosulfan by county in this California-speci fic assessment were gene rated using CDPR PUR data. Thirteen years (1994-2006) of usage data were included in th is analysis. Data from CDPR PUR were obtained for every pesticide applicati on made on every use site at the section level (approximately one square mile) of the public land survey system. BEAD summarized these data to the county level by site, pesticide, a nd unit treated. Calcula ting county-level usage involved summarizing across all applications made within a section and th en across all sections within a county for each use si te and for each pesticide. Figure 2.3 summarizes available historical usage data for the application years from 1994 to 2006.

0 100,000 200,000 300,000 400,000 500,000 600,000Lbs a.i. Or Acres Treated

1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006

Application Year Total Lbs of Endosulfan a.i Applied

Total Acres Treated



### Figure 2.3 Historical usage data for endosulfan

Data show a gradual decrease in crop acreage treate d and lbs of a.i. used for the treatment from 1995 to 2006. Four distinct periods can be identified, namely, 1994, 1995-1997, 1998-2004, and 2005-2006. Usage during these periods decreased from nearly 1⁄2 million lbs (1 st 

### period), to 1⁄4 million lbs (2 nd 

### period), to 155 thousand lbs (3 rd 

### period), to 88 thousand lbs (4 th 

### period). BEAD usage data included average annual pounds applied; average annual area treated, and average 95 th



### and 99 th 

### percentile and maximum a pplication rates for only two periods from 1994 to 1998 and from 1999 to 2006. Therefore, it was necessary to r ecalculate this data to reflect the previously
identified four histor ical usage periods ( Figure 2.3 ). A summary of this recalculated data is provided in Table 2.6 for the 1 st 

### and 2 nd 

### periods and Table 2.7 for the 4 th 

### and 5 th 

### periods. Details are provided only for currently registered endosulfan uses.

Table 2.6 Historical usage of endosulfan for 1994 (1 st period) and 1995-1997 (2 nd period)

1 st

Period: 1994 2 nd Period: 1995-1997 Averages For:
Total. Rate (lbs a.i./A) Total Rate (lbs a.i./A) Crop Use Pattern 1 Lbs a.i. % Average Maximum Lbs a.i. % Average Maximum



### 43Table 2.6 Historical usage of endosulfan for 1994 (1 st period) and 1995-1997 (2 nd period)

1 st

Period: 1994 2 nd Period: 1995-1997 Averages For:
Total. Rate (lbs a.i./A) Total Rate (lbs a.i./A) Crop Use Pattern 1 Lbs a.i. % Average Maximum Lbs a.i. % Average Maximum

Nut trees 1,430 0.35% 0.79 1.72 2,480 1% 1.52 1.99 Citrus (Oranges only) 0 0.00%
- - 3 0.00% 0.75 0.75 Cole crops 1 6,145 1% 0.22 1.01 7,181 4% 0.71 1.7 Cole crops 2 28 0.01% 0.06 0.50 311 0.16% 0.76 0.94

Corn 5,528 1% 0.61 1.51 3,199 2% 0.82 1.19

Cotton 142,259 35% 0.88 1.10 81,639 42% 0.79 0.93 Apple 656 0.16% 0.54 1.50 1,122 1% 1.13 2.13

Fruit trees 3,582 1% 0.81 3.00 13 2,004 1% 1.27 2.5

Lettuce & Brussels
sprouts 37,570 9% 0.81 1.28 31,687 16% 0.9 1
Cucurbits 2 189,485 46% 0.57 2.64 40,125 20% 0.6 2.15 Eggplant 213 0.05% 0.41 0.54 88 0.04% 0.45 0.72
Ornamentals or
shade trees 433 0.11% 0.59 3.00 307 0.16% 0.64 2.82 Potato (No sweet potatoes) 3,697 1% 0.55 0.89 1,808 1% 0.76 0.96 Dry Beans/Peas & Pepper 9,278 2% 0.35 2.00 5,996 3% 0.61 1.32

Carrot 726 0.18% 0.35 0.75 819 0.42% 0.88 1.04 Celery 557 0.14% 0.5 0.75 482 0.25% 0.75 1 Strawberry 540 0.13% 0.59 2.00 283 0.14% 0.86 1.5

Tomato 10,145 2% 0.67 2.39 16,640 8% 0.64 1.07 Currently Labeled
Total 412,289 100% 0.55 2.64 196,190 100% 0.82 2.82 Not currently labeled
Total 2 64,760 0.29 1.84 38,373 0.32 1.54 All Crops 477,049 0.52 2.64 234,563 0.76 2.82

1 Nut Trees= Almond, Hazelnut & Walnut; Cole Crops 1= Broccoli, Cabbage & Cauliflower; Cole Crops 2= Collards, Kale & Mustard Green; Fr uit Trees= Apricot, Nectarine, Peach , Cherry, Pear, Plum & Prune; and Cucurbits= Cucumber, Melons, Pumpkin & Squash

2 Crops not currently labeled were 14% for the 1 st period of which 98% Grapes, Alfalfa & Sugar beet; and 16%
for the 2 nd period of which 95% Grapes, Alfalfa & Sugar beet . Other crops include artichoke, spinach, pecan,
and canola

Table 2.7 Historical usage of endosulfan for 1998-2004 (3 rd period) and 2005-2006 (4 th period)

3 rd

Period: 1998-2004 4 th Period: 2005-2006 Averages For:
Total. Rate (lbs a.i./A) Total Rate (lbs a.i./A) Crop Use Pattern 1 Lbs a.i. % Avg Max Lbs a.i. % Avg Max 95 th % 99 th %

Nut trees 530 0.47% 0.96 1.58 41 0.06% 0.42 0.79 0.82 1.5 Citrus (Oranges 37 0.03% 1.87 3.00 0 0.00% 0 0 0 0

13 This rate of 3.00 lbs a.i/A (reported in Tables 2.5 and 2.6) donates possible misreporting. This value is excluded from calculated statistics because it contains one or more possible misreporting. Misreporting is assumed on a case by case basis but it is considered when calculated rates are less than 0.1, less than 1 lb is applied, less than 1 acre is treated, area units missing or questionable, and number of records for pounds and area do not match.



### 44Table 2.7 Historical usage of endosulfan for 1998-2004 (3 rd period) and 2005-2006 (4 th period)

3 rd

Period: 1998-2004 4 th Period: 2005-2006 Averages For:
Total. Rate (lbs a.i./A) Total Rate (lbs a.i./A) Crop Use Pattern 1 Lbs a.i. % Avg Max Lbs a.i. % Avg Max 95 th % 99 th %
only) Cole crops 1 3,748 3% 0.85 1.48 764 1% 0.69 0.82 0.83 0.98 Cole crops 2 80 0.07% 0.9 1.19 1 0.00% 0.23 0.79 0.9 0.93

Corn 1,027 1% 1.07 1.45 1,143 2% 0.93 0.93 0.93 1

Cotton 40,335 36% 0.89 1.35 17,977 24% 0.83 0.83 0.83 1.01 Apple 395 0.35% 1.26 1.79 84 0.11% 1.98 1.98 1.98 2

Fruit trees 2,520 2% 1.33 2.50 281 0.38% 1.54 2.06 2.08 2.5

Lettuce & Brussels sprouts 25,179 22% 0.92 1.25 27,031 37% 0.38 0.72 0.75 0.99
Cucurbits 2 14,332 13% 0.92 3.00 7,787 11% 0.86 0.98 1 1 Eggplant 44 0.04% 0.73 0.93 41 0.06% 0.5 0.5 0.5 0.55
Ornamentals or
shade trees 248 0.22% 1.11 2.94 53 0.07% 0.29 0.55 0.57 1 Potato (No sweet potatoes) 1,158 1% 0.92 1.00 643 1% 0.95 0.95 0.95 0.96 Dry Beans/Peas & Pepper 2,703 2% 0.78 1.00 2,471 3% 0.85 0.89 0.89 0.99

Carrot 387 0.34% 0.85 0.93 59 0.08% 0.93 0.93 0.93 0.93 Celery 108 0.10% 0.67 1.17 73 0.10% 0.39 0.74 0.77 0.77 Strawberry 83 0.07% 1.14 2.00 2,128 3% 1.2 1.2 1.2 1.51

Tomato 19,842 18% 0.91 1.40 13,343 18% 0.85 0.85 0.85 1.01 112,755 100% 1.00 2.94 73,920 100% 0.77 2.06 2.00 2.42
Crops Not currently labeled 2 41,887 0.75 3.00 13,672 0.93 1.38 1.46 1.48 All Crops 154,642 0.99 2.94 87,592 0.78 2.06 1.99 2.41

1 Nut Trees= Almond, Hazelnut & Walnut; Cole Crops 1= Broccoli, Cabbage & Cauliflower; Cole Crops 2= Collards, Kale & Mustard Green; Fr uit Trees= Apricot, Nectarine, Peach , Cherry, Pear, Plum & Prune; and Cucurbits= Cucumber, Melons, Pumpkin & Squash

2 Crops not currently labeled were 27% for the 3 rd period of which 97% Alfalfa, Grapes & Sugar beet; and 16% for
the 4 th period of which 98% Alfalfa, Grapes & Pecans. Ot her crops include artichoke, spinach, safflower, canola,
Garlic & Oats



### Based on currently registered cr ops, California usage data can be summarized as follows:

(1) Most recent usage data suggest that the top five use patterns for endosulfan are lettuce, cotton, tomatoes, cucurbits, and dry beans ( Table 2.7 , 2005-2006 data). The same five crops are also the dominant usage for earlier ye ars with cotton being on the top for most of the times followed by cucurbits, lettuce, tomatoes, and dry beans ( Table 2.6 and Table
2.7 , 1994, 1995-1997 and 1998-2004 data).

(2) The top five crops constitute between 90 to 94% of the current labeled crop usage, therefore special distribution of these five crops can be ta ken to reflect current most important use areas of endosulfan.

(3) Statistical comparison between current maximu m rates for currently registered crops and the most recent PUR data suggests that report ed actual use rates (i .e., typical rates) are

45

### consistently in the low side. Current labeled rates (lbs a.i./A) compared to reported actual use rates are as follows: average 1.83 compared to 0.77 lbs a.i./A; maximum 2.50 compared to 2.06 lbs a.i./A, ; 95 th 

### % 2.55 compared to 2.00 lbs a.i./A, and 99 th 

### % maximum 2.91compared to 2.42 lbs a.i./A. With few exceptions 14 

### , current labeled rates are generally higher than the mo st recent typical use rates.

Figure 2.4 provides a summary of the most recent e ndosulfan usage along with the general
habitat areas of the CRLF and th e San Francisco Bay species. Figure 2.4 shows clearly that the majority (nearly 82%) of the recent endosul fan use was in three counties: Fresno, Kings, and Imperial. Top ten use category constitutes nearly 97% of the use which includes the three counties just mentioned in addition to Riverside, Kern, Yolo, Siskiyou, Tulare, and Solano counties. In an additional 14 counties, (San Benito, Madera, Monterey, Colusa, Merced, Santa Clara, San Joaquin, Ventura, Sonoma, Los Angeles, Placer, Napa, Glenn, and Santa Barbar).usage is very small ranging from 1 lb a.i to 647 lbs a .. Maps of species occurrence and their designated crit ical habitat (where applicable ) in relation to agricultural areas in California are provided in Appendix E

.

14 Statistics exclude data where reported rates are exceptionall y high due to possible misreporting. Any rate reported in Tables 2.5 and 2.6 to equal 3 lbs a.i. /A are excluded because it contains one or more possible misreporting. Misreporting is assumed on a case by case basis but is consid ered when calculated rates are less than 0.1, less than 1 lb is applied, less than 1 acre is treated, area units missing or questionable and number of records for pounds and
area do not match.



### 46Figure 2.4 Endosulfan usage and acreage for the top five crop use patterns (CA- PUR data; Average for 2005- 2006)



### Finally, the top usage crops in the three t op ranked usage counties are lettuce, tomatoes, cucurbits, dry beans, and corn for Fresno C ounty, cotton, tomatoes, and cole crops for Kings County, and cucurbits, cotton, a nd lettuce for Imperial County ( Figure 2.5 

### ). Alfalfa was the major crop used in the “not curr ently registered category”

.

47

### Table 2.8 provides a summary of the current distribution, habitat requirements, and life history parameters for the listed species being assessed. More detailed life-hi story and distribution
information can be found in Attachments 1 and 3

.

48 0 5

, 0 0 0 1 0

, 0 0 0 1 5

, 0 0 0 2 0

, 0 0 0 2 5

, 0 0 0Endosulfan Use (lbs. a.i/Crop)

L e t t u c e C o t to

n Tom

a to

e s C u cu

r b i t s C o r n D r y

b ea

ns A

Crop (Notes: Not currently registered crop was l l o t h e r s A p p

le

&

P lu

m

s C o le

c

r o ps N o t R e g

i s te

r ed

mainly alfalfa) Fresno Kings Imperial



### Figure 2.5 Distribution of endosulfan usage for the top usage counties of Fresno, Kings, and Imperial



### 2.5 Assessed SpeciesTable 2.8 Summary of Current Distribution, Habitat Requirements, and Life History Information for the Assessed Listed SpeciesAssessedSpecies1SizeCurrent RangeHabitat TypeDesignatedCriticalHabitat?ReproductiveCycleDietCalifornia redlegged frog(Rana auroradraytonii)Adult(85-138 cmin length),Females –9-238 g,Males –13-163 g;Juveniles(40-84 cmin length)Northern CA coast, northernTransverse Ranges, foothills ofSierra Nevada, and in southern CAsouth of Santa BarbaraFreshwater perennialor near-perennialaquatic habitat withdense vegetation;artificialimpoundments;riparian and uplandareasYesBreeding: Nov. to Apr.Tadpoles: Dec. to Mar.Young juveniles: Mar. toSept.Aquatic-phase2: algae,freshwater aquaticinvertebratesTerrestrial-phase:aquatic and terrestrialinvertebrates, smallmammals, fish andfrogsCalifornia tigersalamander(Ambystomacaliforniense)50 gThere are two distinct populationsegments; one in Santa BarbaraCounty and the other in SonomaCounty.Freshwater pools orponds (natural orman-made, vernalpools, ranch stockponds, other fishlessponds); Grassland oroak savannahcommunities, in lowfoothill regions;Small mammalburrowsYesEmerge from burrows andbreed:fall and winterrainsEggs:laid in pond Dec. –Feb., hatch: after 10 to 14daysLarval stage: 3-6 months,until the ponds dry out,metamorphose late springor early summer, migrateto small mammal burrowsAquatic Phase:algae,snails, zooplankton,small crustaceans, andaquatic larvae andinvertebrates, smallertadpoles of Pacific treefrogs, CRLF, toads;Terrestrial Phase:terrestrial invertebrates,insects, frogs, andwormsSan Franciscogarter snake(Thamnophissirtalistetrataenia)Adult(46-131 cmin length),Females –227 g,Males –113 g;Juveniles(18–20 cmin length)San Mateo CountyDensely vegetatedfreshwater pondsnear open grassyhillsides; emergentvegetation; rodentburrowsNoOviparous Reproduction3Breeding: Spring (Mar.and Apr.) and Fall (Sept.to Nov.)Ovulation and Pregnancy:Late spring and earlysummerYoung: Born 3-4 monthsafter matingJuveniles: frogs(Pacific tree frog,CRLF, and bullfrogsdepending on size) andinsectsAdults: primarily frogs(mainly CRLFs; alsobullfrogs, toads); to alesser extent newts;freshwater fish andinvertebrates; insectsand small mammalsSalt marsh harvestmouseAdult8 – 14 gNorthern subspecies can be foundin Marin, Sonoma, Napa, Solano,Dense, perennialcover with preferenceNoBreeding:March –NovemberLeaves, seeds, andplant stems; may eat49Table 2.8 Summary of Current Distribution, Habitat Requirements, and Life History Information for the Assessed Listed SpeciesAssessedSpecies1SizeCurrent RangeHabitat TypeDesignatedCriticalHabitat?ReproductiveDietCycle(Reithrodontomysraviventris)and northern Contra Costacounties. The southern subspeciesoccurs in San Mateo, Alameda,and Santa Clara counties withsome isolation populations inMarin and Contra Costa counties.for habitat in themiddle and upperparts of the marshdominated bypickleweed andperipheral halophytesas well as similarvegetation in dikedwetlands adjacent tothe BayGestation period:21 – 24daysinsects; prefers “freshgreen grasses” in thewinter and pickleweedand saltgrass during therest of the year; drinksboth salt and freshwaterSan Joaquin kitfox(Vulpes macrotismutica)Adult~2 kgAlameda, Contra Costa, Fresno,Kern, Kings, Madera, Merced,Monterey, San Benito, SanJoaquin, San Luis Obispo, SantaBarbara, Santa Clara, Stanislaus,Tulare and Ventura countiesA variety of habitats,including grasslands,scrublands (e.g.,chenopod scrub andsub-shrub scrub),vernal pool areas, oakwoodland, alkalimeadows and playas,and an agriculturalmatrix of row crops,irrigated pastures,orchards, vineyards,and grazed annualgrasslands. Kit foxesdig their own dens,modify and use thosealready constructedby other animals(ground squirrels,badgers, andcoyotes), or usehuman-madestructures .(culverts,abandoned pipelines,or banks in sumps orroadbeds). TheyNo, but hasdesignatedcore areasMating and conception:late December - March.Gestation period: 48 to 52days.Litters born: February -late MarchPups emerge from theirdens at about 1-month ofage and may begin todisperse after 4 – 5months usually in Aug. orSept.Small animalsincluding blacktailedhares, desertcottontails, mice,kangaroo rats, squirrels,birds, lizards, insectsand grass. It satisfies itsmoisture requirementsfrom prey and does notdepend on freshwatersources.50Table 2.8 Summary of Current Distribution, Habitat Requirements, and Life History Information for the Assessed Listed SpeciesAssessedSpecies1SizeCurrent RangeHabitat TypeDesignatedCriticalHabitat?ReproductiveDietCyclemove to new denswithin their homerange often (likely toavoid predation bycoyotes)Bay checkerspotbutterfly (BCB)(Euphydryaseditha bayensis)Adultbutterfly - 5cm in lengthSanta Clara and San MateoCounties [Because the BCBdistribution is considered ametapopulation, any site withappropriate habitat in the vicinityof its historic range (Alameda,Contra Costa, San Francisco, SanMateo, and Santa Clara counties)should be considered potentiallyoccupied by the butterfly (USFWS1998, p. II-177)].1) Primary habitat –native grasslands onlarge serpentineoutcrops;2) Secondary habitat– ‘islands’ of smallerserpentine outcropswith native grassland;3) Tertiary habitat –non-serpentine areaswhere larval foodplants occurYesLarvae hatch in March –May and grow to the 4thinstar in about two weeks.The larvae enter into aperiod of dormancy(diapause) that laststhrough the summer. Thelarvae resume activitywith the start of the rainyseason. Larvae pupateonce they reach a weightof 300 - 500 milligrams.Adults emerge within 15to 30 days depending onthermal conditions, feedon nectar, mate and layeggs during a flightseason lasting 4 -6 wkslfrom late Feb.- early MayObligate with dwarfplantain. Primary dietis dwarf plantain plants(may also feed onpurple owl’s-clover orexserted paintbrush ifthe dwarf plantainssenesce before thelarvae pupate). Adultsfeed on the nectar of avariety of plants foundin association withserpentine grasslandsValley elderberrylonghorn beetle(Desmoceruscalifornicusdimorphus)Males:1.25–2.5cmlengthFemales:1.9–2.5 cmlengthCentral Valley of California (fromShasta County to Fresno County inthe San Joaquin Valley)Completelydependent on its hostplant, elderberry(Sambucus species),which is a commoncomponent of theremaining riparianforests and adjacentupland habitats ofCalifornia’s CentralValleyYesThe larval stage may last2 years living within thestems of an elderberryplant. Then larvae enterthe pupal stage andtransform into adults.Adults emerge and areactive from March to Junefeeding and mating, whenthe elderberry producesflowers.Obligates withelderberry trees(Sambucus sp). Adultseat the elderberryfoliage until about Junewhen they mate. Uponhatching the larvaetunnel into the treewhere they will spend1-2 years eating theinterior wood which istheir sole food source.51521For more detailed information on the distribution, habitat requirements, and life history information of the assessed listedspecies, seeAttachment 32For the purposes of this assessment, tadpoles and submerged adult frogs are considered “aquatic” because exposure pathways in the water are considerablydifferent than those that occur on land.3Oviparous = eggs hatch within the female’s body and young are born live.

### 2.6 Designated Critical Habitat

Critical habitat has been designated for the CRLF, BCB, CTS, and VELB. ‘Critical habitat’ is defined in the ESA as the geogra phic 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 speci al management to protect the listed species. It may also include areas outside the occupied area at the tim e of listing if such areas are
‘essential to the conservation of the species.’ Critical ha bitat receives protection under Section 7 of the ESA through prohibition agai nst destruction or adverse modification with regard to actions carried out, funded, or authorized by a federal Agency. Section 7 requires consultation on federal ac tions that are likely to re sult in the destruction or
adverse modification of critical habitat.

To be included in a critical habitat desi gnation, the habitat must be ‘essential to the conservation of the species.’ Critical hab itat designations identify, to the extent known using the best scientific a nd commercial data available, habitat areas that provide essential life cycle needs of the species or areas that contai n 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 a nd for normal behavior; food, water, air, light, minerals, or other nutritional or physiolo gical requirements; cove r or shelter; sites for breeding, reproduction, rearing (or developmen t) of offspring; a nd habitats that are protected from disturbance or are represen tative of the histor ic geographical and ecological distributi ons of a species. Table 2.9 describes the PCEs for the critical habitats designated for the CRLF, CTS, BCB, and VELB.

Table 2.9 Designated Critical Habitat PCEs for the CRLF, CTS, BCB and VELB Species PCEs Reference Alteration of channel/pond morphology or geometry and/or increase in sediment deposition within the stream channel or pond. 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 char acteristics necessary for normal growth and viability of CRLFs and their food source.Reduction and/or modification of aquatic-based food sources for premetamorphs ( e.g., algae) 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 th at 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 CRLF

Alteration of chemical characteris tics necessary for normal growth 50 CFR 414.12(b),
2006



### 53Table 2.9 Designated Critical Habitat PCEs for the CRLF, CTS, BCB and VELB Species PCEs Reference and viability of juvenile and adult CRLFs and their food source. Standing bodies of fresh water, including natural and man-made ( e.g ., stock) ponds, vernal pools, and dune ponds, and other ephemeral or permanent water bodies that typically become inundated during winter rains and hold water for a sufficient length of time ( i.e ., 12 weeks) necessary for th e species to complete the aquatic (egg and larval) portion of its life cycle 2
Barrier-free uplands adjacent to breeding ponds that contain small mammal burrows. Small mammals are essential in creating the underground habitat that juvenile and adult California tiger salamanders depend upon for food, shelter, and protection from the elements and predation California tiger

salamander

Upland areas between breeding loca tions (PCE 1) and areas with small mammal burrows (PCE 2) that allow for dispersal among such
sites FR Vol. 69 No. 226 CTS, 68584, 2004

The presence of annual or perennial grasslands with little to no overstory that provide north/south and east/west slopes with a tilt of more than 7 degrees for larval host plant survival during periods of atypical weather (e.g., drought). The presence of the primary larv al host plant, dwarf plantain ( Plantago erecta ) (a dicot) and at least one of the secondary host plants, purple owl's-cl over or exserted paintbrush, are required for reproduction, feeding, and larval development. The presence of adult nect ar sources for feeding. Aquatic features such as wetlands, sp rings, seeps, streams, lakes, and ponds and their associated banks, that provide moisture during periods of spring drought; these features can be ephemeral, seasonal,
or permanent. Soils derived from serpentinite ultramafic rock (Montara, Climara, Henneke, Hentine, and Obispo soil series) or similar soils (Inks, Candlestick, Los Gatos, Fagan, and Barnabe soil series) that provide areas with fewer aggr essive, nonnative plant species for larval host plant and adult nectar plant survival and reproduction. 2 Bay Checkerspot

Butterfly

The presence of stable holes and cracks in the soil, and surface rock outcrops that provide shelter fo r the larval stage of the bay checkerspot butterfly during summer diapause. 2 66 FR 21449 21489,
2001

Valley Elderberry Longhorn

Beetle Areas that contain the host plant of this species [ i.e ., elderberry trees ( Sambucus sp.)] (a dicot) 43 FR 35636 35643,
1978

1 These PCEs are in addition to more general requirements for habitat areas that provide essential life cycle needs of the species such as, space for individual an d population growth and fo r normal behavior; food, water, air, light, minerals, or other nutritional or phy siological 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 ge ographical and ecological di stributions of a species.

2 PCEs that are abiotic, including, 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.



### More detail on the designated critical habitat applicable to this assessment can be found
in Attachment 1 (for the CRLF) and Attachment 3 (for CTS, BCB, and VELB). Activities that may destroy or adversely modify critical habi tat are those that alter the

54

### PCEs and jeopardize the continued existence of the species. Evaluation of actions related to use of endosulfan that may alter the PCEs of the designated cri tical habitat for the CRLF, CTS, BCB, and VELB form the basis of the critical habitat impact analysis.

As previously noted in Section 2.1 , the Agency believes that th e analysis of direct and indirect effects to listed species provides the basis for an analysis of potential effects on the designated critical habitat. Because endos ulfan is expected to directly impact living organisms within the action area, critical ha bitat analysis for endosulfan is limited in a practical sense to those PCEs of critical habitat that are biological or that can be reasonably linked to biological ly mediated processes.

2.7 Action Area

For listed species assessment purposes, the action area is considered to be the area affected directly or indirec tly by the federal action and not merely the immediate area involved in the action (50 CFR 402.02). It is recognized th at the overall action area for the national registration of endos ulfan is likely to encompass considerable portions of the United States based on the large array of agri cultural uses. However, the scope of this
assessment limits considerati on of the overall action area to those portions that may be applicable to the protection of the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and their designated critical habitat within the state of California. Although the watershed for the San Francisco Bay extends northward into the very southwestern portion of Lake County, Oregon, and westward into the western edge of Washoe County, Nevada, the non-California portions of the waters hed are small and very rural with little, if any, agriculture. Therefore, no use of endos ulfan is expected in these areas, and they are not considered as part of the action area applicable to this assessment.

The definition of action area requires a stepwise approach that begins with an understanding of the federal act ion. The federal action is de fined by the currently labeled uses for endosulfan. An analysis of labele d uses and review of available product labels was completed. Several of the currently labeled uses are special local needs (SLN) uses or are restricted to specific states and are excluded from th is assessment. In addition, a
distinction has been made between food use crops and those that are non-food/nonagricultural uses. For those uses relevant to the assessed species, the analysis indicates that, for endosulfan, the following agricultural us es are considered as part of the federal
action evaluated in this assessment:

(1) Terrestrial Food Crops Apricot, Cherry, Nectarine, Peach, Pear, Plum & Prune Cabbage & Cauliflower Carrot & Celery
Collards& Kale Cucurbits (Cucumber, Melons, Pumpkin & Squash)
Hazelnuts & Walnuts Lettuce & Brussels Sprouts Pepper

55

### Strawberry

(2) Terrestrial + Greenhouse Food Crops

Tomato

(3) Terrestrial Food + Feed Crops
Almonds Apple Beans & Peas (dry)
Broccoli
Cotton Eggplant
Mustard Green
Potato & Sweet Potato Sweet corn for fresh market only

(4) Terrestrial Non-Food Crops
Citrus
Ornamentals or Shade Trees

Following a determination of the assessed uses , an evaluation of the potential “footprint” of endosulfan 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 fo r the state of California. Th e initial area of concern is defined as all land cover types and the stream reaches within the land cover areas that represent the labeled uses described above. A map repr esenting all the land cover types that make up the initial area of conc ern for endosulfan is presented in Figure 2.6

.

56Figure 2.6 Initial area of co ncern, or “footprint” of pote ntial use, for endosulfan



### Once the initial area of concern is defined, the next step is to define the potential boundaries of the action area by determining the ex tent of offsite tran sport via spray drift and runoff where exposure of one or more ta xonomic groups to the pe sticide exceeds the listed species LOCs.

The Agency’s approach to defining the acti on area under the provisi ons of the Overview Document (USEPA 2004) consider s the results of the risk assessment process to establish

57

### boundaries for that action area with the understa nding that exposures below the Agency’s defined Levels of Concern (LOCs) constitute a no-effect threshold. Deriving the geographical extent of this portion of the action area is based on consideration of the types of effects that endosu lfan may be expected to have on the environment, the exposure levels to endosulfan that are associated with those e ffects, and the best available information concerning the use of endosulfan and its fate and transport within the state of California. Specific measures of ecological e ffect for the assessed species that define the action area include any direct and indirect toxic effect to the assessed species 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 poi nt where environmental exposures are below any measured lethal or sublethal effect thre shold for any biological entity at the whole organism, organ, tissue, and cellu lar level of organization. In situations where it is not possible to determine the threshold for an obs erved effect, the action area is not spatially
limited and is assumed to be the entire state of California.

Based on a review of the available toxici ty data in ECOTOX a nd toxicity studies submitted to the Agency, several studies we re identified that lacked a defined NOAEC (i.e., a concentration were no observable adverse effects were documented; see Appendix J) . For example, Hansen and Cripe (1991; ECOTOX # 115297) reported a LOAEC of < 0.27 ug a.i./L for sheepshead minnow resulti ng from 28-d, flow through exposures. Due to the lack of a defined NOAEC (i.e., no obs erved adverse effect concentration), the spatial extent of the action area ( i.e ., the boundary where exposure s and potential effects are less than the Agency’s LOC) cannot be determined for endosulfan. Therefore, it is assumed that the action area encompasses the en tire state of California, regardless of the spatial extent ( i.e ., initial area of concern or foot print) of the pesticide use(s).

2.8 Assessment Endpoints and Mea sures of Ecological Effect

Assessment endpoints are defined as “explicit expressions of the ac tual environmental value that is to be protected.” 15 

### Selection of the assessment endpoints is based on valued entities ( e.g., CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB), organisms important in the life cycle of the assessed species, and the PCEs of its designa ted critical habitat), the ecosystems potentially at risk ( e.g., waterbodies, riparian vegetation, and upland and dispersal habitats), the migra tion pathways of endosulfan ( e.g., runoff, spray drift, etc .), and the routes by which ecological r eceptors are exposed to endosulfan (e.g., direct

contact, etc.).

2.8.1 Assessment Endpoints

Assessment endpoints for the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB include direct toxic effects on the survival, reproduction, and growth of individuals, as well as indirect effects, such as reduction of the prey base or modification of its habitat. In addition, potential modification of critic al habitat is assesse d by evaluating potential effects to PCEs, which are components of the habitat areas that provide essential life

15 From U.S. EPA (1992). Framework for Ecological Risk Assessment. EPA/630/R-92/001.



### 58

### cycle needs of the assessed species. 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 re gistrant-submitted guidel ine tests that are performed on a limited number of organisms. Additional ecological effects data from the open literature are al so considered. It should be not ed that assessment endpoints are
limited to direct and indirect effects associated with surviv al, growth, and fecundity, and
do not include the full suite of sublethal effect s used to define the action area. According to the Overview Document (USEPA 2004), the Agency relies on acute and chronic effects endpoints that are either direct measures of impairme nt 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 included in Section 4
of this document.

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 i nvertebrates, aquatic plants, birds (surrogate for terrestrial- phase amphibians and reptiles), mammals, terrestrial invertebrates, and terrestrial plants. Acute (sho rt-term) and chronic (long-term) toxicity information is characterized based on registrant-submitted studies and a comprehensive review of the open literature on endosulfan.

Table 2.10 identifies the taxa used to assess the po tential for direct and indirect effects
from the uses of endosulfan for each liste d species assessed here. The specific assessment endpoints used to a ssess the potential for direct a nd indirect effects to each listed species are provided in Table 2.11

.

59Table 2.10 Taxa Used in the Analyses of Direct and Indirect Effects of E ndosulfan for the Assessed Listed Species.
Listed Species Birds Mammals Terr.
Plants Terr.
Inverts. FW Fish FW
Inverts. Estuarine
/Marine

Fish Estuarine
/Marine
Inverts. Aquatic
Plants

California redlegged frog Direct

Indirect (prey) Indirect (prey) Indirect (habitat) Indirect (prey) Direct

Indirect (prey) Indirect (prey) N/A N/A Indirect (food/ habitat)

California tiger
salamander Direct N/A Indirect (habitat) Indirect (prey) Direct

Indirect (prey) Indirect (prey) N/A N/A Indirect (food/ habitat)

San Francisco garter snake Direct

Indirect (prey) Indirect (prey) Indirect (habitat) Indirect (prey) Indirect (prey) Indirect (prey) N/A N/A Indirect (habitat)

Salt marsh
harvest mouse Indirect (rearing

sites) Direct

Indirect (rearing

sites) Indirect (food, habitat) Indirect (prey) N/A N/A N/A N/ A Indirect (habitat)

San Joaquin
kit fox Indirect (prey) Direct

Indirect (prey) Indirect (food/ habitat) Indirect (prey) N/A N/A N/A N/A N/A

Bay checkerspot butterfly N/A N/A Indirect (food/ habitat)
* Direct N/A N/ A N/A N/A N/A

Valley elderberry longhorn
beetle N/A N/A Indirect (food/ habitat)
* Direct N/A N/ A N/A N/A N/A

N/A = Not applicable
Terr. = Terrestrial
Invert. = Invertebrate
FW = Freshwater * = obligate relationship



### 60Table 2.11 Taxa and Assessment Endpoints Us ed to Evaluate the Potential for the Use of Endosulfan to Result in Direct and Indirect Effects to the Assessed Listed Species.
Taxa Used to Assess
Direct and/or Indirect
Effects to Assessed Species Assessed Listed Species Assessment Endpoints Measures of Ecological Effects

Direct Effect

– -Aquatic-phase CRLF - Aquatic-phase CTS Survival, growth, and reproduction of individuals
via direct effects 1. Freshwater Fish and Aquatic-phase Amphibians

Indirect Effect (prey) -Aquatic-phase and Terrestrial-phase CRLF
- SFGS
- CTS Survival, growth, and reproduction of individuals
via indirect effects on aquatic prey food supply ( i.e., fish and aquatic-phase amphibians) 1a. Common carp acute LC 50 1b. Common carp NOAEC (estimated based on acute-chronic ratio)

2. Freshwater
Invertebrates Indirect Effect (prey) -Aquatic-phase and Terrestrial-phase CRLF
- SFGS
- CTS Survival, growth, and reproduction of individuals
via indirect effects on aquatic prey food supply ( i.e., freshwater invertebrates) 2a. Mayfly LC 50 2b. Mayfly NOAEC (estimated based on acute-chronic ratio)

3. Aquatic Plants (freshwater/marine) Indirect Effect (food/habitat) - Aquatic-phase CRLF
- SFGS
- SMHM
- CTS Survival, growth, and reproduction of individuals
via indirect effects on habitat, cover, food supply, and/or primary productivity ( i.e., aquatic plant community) 5a. No data for Vascular aquatic plants 5b. Green alga EC 50

Direct Effect -Terrestrial-phase CRLF
- SFGS
- CTS Survival, growth, and reproduction of individuals
via direct effects 6. Birds

Indirect Effect (prey/habitat from nests) -Terrestrial-phase CRLF
- SFGS
- SMHM
- SJKF Survival, growth, and reproduction of individuals
via indirect effects on terrestrial prey (birds) 6a. Mallard LD 50 6b. Mallard NOAEC

Direct Effect
- SMHM
- SJKF Survival, growth, and reproduction of individuals
via direct effects 7. Mammals

Indirect Effect (prey/habitat from burrows) -Terrestrial-phase CRLF
- SFGS
- SMHM
- SJKF Survival, growth, and reproduction of individuals
via indirect effects on terrestrial prey (mammals) 7a. Laboratory rat acute LD 50 7b. Laboratory rat chronic NOAEC

Direct Effect
- BCB

- VELB Survival, growth, and reproduction of individuals
via direct effects 8. Terrestrial
Invertebrates

Indirect Effect (prey) Survival, growth, and 8a. Beet webworm acute contact LD 50



### 61Table 2.11 Taxa and Assessment Endpoints Us ed to Evaluate the Potential for the Use of Endosulfan to Result in Direct and Indirect Effects to the Assessed Listed Species. -Terrestrial-phase CRLF
- SFGS
- SMHM
- SJKF
- CTS reproduction of individuals
via indirect effects on terrestrial prey (terrestrial invertebrates)

Indirect Effect(food/habitat) (nonobligate relationship) -Terrestrial-phase CRLF
- SFGS
- SMHM
- SJKF
- CTS 9. Terrestrial Plants

Indirect Effect (food/habitat) (obligate relationship)
- BCB

- VELB Survival, growth, and reproduction of individuals
via indirect effects on food and habitat ( i.e., riparian and upland vegetation) 9a. No toxicity data for terrestrial plants



### 2.8.2 Assessment Endpoints for De signated Critical Habitat

As previously discussed, designa ted critical habitat is assessed to evaluate actions related to the use of endosulfan that may alter th e PCEs of the assess ed species’ designated
critical habitat. PCEs for the assesse d species were previously described in Section 2.6

. Actions that may affect critic al habitat are those that alte r the PCEs and jeopardize the continued existence of the assessed species. 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 endosulfan effects data are available.

Some components of these PCEs are associ ated with physical abiotic features ( e.g ., presence and/or depth of a water body, or distance between two s ites), which are not expected to be measurably altered by use of pesticides. Measures of ecological effect used to assess the potential for effects to the critical habitat of the CRLF, BCB, VELB,
and CTS are described in Table 2.12

.

Table 2.12 Summary of Assessment Endpoints and Measures of Ecological Effect for Primary Constituent Elements of Design ated Critical Habitat for CR LF, BCB, VELB, and CTS.

Taxon Used to
Assess
Modification of
PCE Assessed Listed Species Associated
with the PCE Assessment Endpoints Measures of Ecological Effects

1. Freshwater Fish and Aquatic-phase Amphibians Direct Effect

– -Aquatic-phase
CRLF Survival, growth, and reproduction of
individuals via direct
effects 1a. Common carp acute LC 50 1b. Common carp NOAEC (estimated based on acute-chronic ratio)



### 62Table 2.12 Summary of Assessment Endpoints and Measures of Ecological Effect for Primary Constituent Elements of Design ated Critical Habitat for CR LF, BCB, VELB, and CTS.

Taxon Used to
Assess
Modification of
PCE Assessed Listed Species Associated
with the PCE Assessment Endpoints Measures of Ecological Effects

Indirect Effect (prey) -Aquatic and terrestrial-phase
CRLF Modification of critical habitat via change in aquatic prey food supply ( i.e., fish and aquatic-phase amphibians)

2. Freshwater
Invertebrates Indirect Effect (prey) -Aquatic-phase and - Terrestrial-phase
CRLF Survival, growth, and reproduction of
individuals via indirect effects on aquatic prey food supply ( i.e.,
freshwater invertebrates) 2a. Mayfly LC 50 2b. Mayfly NOAEC (estimated based on acute-chronic ratio)

5. Aquatic Plants (freshwater/marine) Indirect Effect (food/habitat) -Aquatic-phase
CRLF
- CTS Modification of critical habitat via change in habitat, cover, food supply, and/or primary productivity ( i.e., aquatic plant community) 5a. No data for Vascular aquatic plants 5b. Green alga EC 50

Direct Effect -Terrestrial-phase
CRLF Survival, growth, and reproduction of
individuals via direct
effects 6. Birds

Indirect Effect (prey) - Terrestrial-phase
CRLF Modification of critical habitat via change in terrestrial prey (birds) 6a. Mallard LD 50 6b. Mallard NOAEC

7. Mammals Indirect Effect (prey/habitat from burrows) -Terrestrial-phase
CRLF
-CTS Modification of critical habitat via change in terrestrial prey (mammals) 7a. Laboratory rat acute LD 50 7b. Laboratory rat chronic
NOAEC

Direct Effect
-BCB
-VELB Survival, growth, and reproduction of
individuals via direct
effects 8. Terrestrial
Invertebrates

Indirect Effect (prey) -Terrestrial-phase --
CRLF
-CTS Modification of critical habitat via change in terrestrial prey (terrestrial invertebrates) 8a. Beet webworm acute contact

LD 50

9. Terrestrial Plants Indirect Effect(food/habitat) (nonobligate relationship) Modification of critical habitat via change in food and habitat ( i.e., riparian and upland 9a. No toxicity data for terrestrial plants



### 63Table 2.12 Summary of Assessment Endpoints and Measures of Ecological Effect for Primary Constituent Elements of Design ated Critical Habitat for CR LF, BCB, VELB, and CTS.

Taxon Used to
Assess
Modification of
PCE Assessed Listed Species Associated
with the PCE Assessment Endpoints Measures of Ecological Effects

-Terrestrial-phase
CRLF
- CTS

Indirect Effect (food/habitat) (obligate relationship)
- BCB
- VELB vegetation)



### 2.9 Conceptual Model

2.9.1 Risk Hypotheses

Risk hypotheses are specific assumptions about potential adverse effects ( i.e., changes in assessment endpoints) and may be based on theory and logic, empirical data, mathematical models, or probability models (U .S. EPA, 1998). For this assessment, the risk is stressor-linked, where th e stressor is the rel ease of endosulfan to the environment. The following risk hypotheses are presumed in this assessment:

The labeled use of endosulfan within the action area may:

• Directly affect the CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS by causing mortality or by adversely a ffecting growth or fecundity;

• Indirectly affect the CRLF, SFGS, SM HM, BCB, VELB, SJKF, and CTS and/or modify their designated critic al habitat by reducing or changing the composition of food supply;

• Indirectly affect the CRLF, SFGS, SMHM, and CTS and/or modify their designated critical habitat by reducing or changing the comp osition of the aquatic plant community in the species’ current range, thus affecting primary productivity and/or

cover;

• Indirectly affect the CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS and/or modify their designated critic al habitat by reducing or changing the composition of the terrestrial plant community in the species’ current range;

• Indirectly affect the CRLF SFGS, SMHM , SJKF, and CTS and/or modify their designated critical habitat by re ducing or changing aquatic ha bitat in their current range (via modification of water quality parameters, habitat morphology, and/or sedimentation).

64

### 2.9.2 Diagram

The conceptual model is a graphic representation of the structure of the risk assessment. It specifies the endosulfan re lease mechanisms, biological r eceptor types, and effects endpoints of potential concern. The conceptual models for aquatic and terrestrial phases of the CRLF, SFGS, SMHM, BCB, VELB, SJKF , and CTS and the conceptual models for the aquatic and terrestrial PCE com ponents of critical habitat are shown in Figure 2.7
and Figure 2.8

. Although the conceptual models for direct/indirect effects and modification of designated critical habitat PCEs are shown on the same diagrams, the potential for direct/indirect effects and modifi cation of PCEs will be evaluated separately in this assessment. Exposure routes shown in dashed lines are considered insignificant routes of exposure (e.g., groundwater seepage into surface water).

Figure 2.7 Conceptual Model for Endosulfan Effects on the Assessed Species and their Critical Habitat in the Aquatic Environment Stresso r

Source

Receptors

Attribute Change Spra y drift

Fish/aquaticphase amphibians
**Piscivorous
mammals and
birds

Individual organisms
Reduced survival Reduced growth Food chain Reduction in algae 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 Surface water/ Sediment Runoff

Aquatic Animals
Invertebrates
Vertebrates Uptake/gills or integument

Ingestion Ingestion Uptake/gills or integument

A quatic Plants
Non-vascular
Vascula r Uptake/cell, roots, leaves Riparian plant
terrestrial

exposure pathways (see

Figure 2.8) Long range atmospheric

transport

Wet/dry deposition Groundwate r Soil



### Exposure
Media α - and β - Endosulfan Applied to Use Sites + Sulfate Formation



### 65

### Stresso r

Source

Receptors

Attribute Change α - and β - Endosulfan Applied to Use Sites + Sulfate Formation

Direct application Spray drift

Birds/terrestrialphase amphibians/ reptiles/mammals

Terrestrial

insects

Individual organisms
Reduced survival Reduced growth 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 Terrestrial/riparian plants grasses/forbs, fruit, seeds (trees, shrubs) Runoff

Mammals

/ Birds 

### Exposure
Media Soil

Ingestion Ingestion

Ingestion Ingestion Dermal uptake/Ingestion Long range atmospheric

transport

Root uptake Wet/dry deposition

Terrestrialphase amphibians

Ingestion



### Figure 2.8. Conceptual Model for Endosulfan Effects on the Assessed Species and
their Critical Habitat in the Terrestrial Environment

2.10 Analysis Plan

In order to address the risk hypot hesis, the potential for direct and indirect effects to the CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS, prey items, and habitat is estimated based on a taxon-level approach. In the followi ng sections, the use, environmental fate, and ecological effects of endosulfan are character ized and integrated to assess the risks. This is accomplished using a risk quotient (ratio of exposure conc entration 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 likeli hood 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 pa rticular uses of endosulfan is estimated using the probit dose-response slope and either the level of concern (discussed below) or actual calculated risk quotient value.

2.10.1 Measures to Evaluate the Risk Hypothesis and Conceptual Model

66

### 2.10.1.1 Measures of Exposure

The environmental fate properties of endos ulfan along with available monitoring data indicate that runoff, spray drift, and long -range atmospheric trans port are the principle potential transport mechanisms of endosulfan to the aquatic and terrestrial habitats of the CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CT S. In this assessment, transport of endosulfan through runoff and spray drift is c onsidered in deriving quantitative estimates of CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS exposure to endosulfan , in addition to exposure of their prey and hab itats. Assessment of long-range atmospheric transport is addressed qualit atively through a review of av ailable monitoring data from California but not explicitly modeled due to the lack of models that quantitatively predict far-field pesticide concentrations resulting from near-field loadings.

Measures of exposure are based on aquatic and terrestrial models that predict estimated environmental concentrations (EECs) of e ndosulfan using maximum labeled application rates and methods of application. The mode ls 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 te rrestrial EECs on food items is T-REX. These models are parameterized using relevant reviewed registrant-submitted
environmental fate data.

PRZM (Carsel et al 1997) v3.12.2, Ma y 2005 and EXAMS (Burns, 1997) v2.98.4.6, April 2005 are screening simulation models coupled with the i nput shell pe5.pl (Aug 2007) to generate daily exposures and 1-in-10 year EECs of endosulfan that may occur in surface water bodies adjacent to application sites receiving endosulfan through runoff and spray drift. PRZM simulates pesticide a pplication, movement and transformation on an agricultural field and the result ant 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 standa rd scenario used fo r ecological pesticide assessments assumes application to a 10-hectar e agricultural field that drains into an adjacent 1-hectare water body, 2-meters deep (20,000 m 3 

### volume) with no outlet.
PRZM/EXAMS was used to estimate screeni ng-level exposure of aquatic organisms to endosulfan. The measure of exposure for aquati c species is the 1-in- 10 year return peak or rolling mean concentration. The 1-in-1 0-year 60-day mean is used for assessing chronic exposure to fish; the 1-in-10-year 21-day mean is used for assessing chronic exposure for aquatic invertebrates.

For endosulfan, aquatic exposures were mode led separately for the parent isomers ( ά and β ) and the primary degradate of concern (e ndosulfan sulfate). The resulting daily
concentrations were then summed to form a 30- year time series for total endosulfan (sum
of ά

, β and endosulfan sulfate). Due to similar acute toxicity and structure of the TGAI and endosulfan sulfate, modeled or meas ured environmental exposures of total endosulfan (sum of ά

, β and endosulfan sulfate) were comp ared with toxicity data for the TGAI. For sediment-borne exposures, toxic ity data were availa ble only for endosulfan sulfate, and thus, comparisons of total endos ulfan EECs were made to toxicity estimates
for endosulfan sulfate.

67

### Exposure estimates for the terrestrial animals as sumed 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, Oct. 9, 2008). This model incorporates the Kene ga nomograph, as modified by Fletcher et al. (1994), which is based on a large set of actua l field residue data. The upper limit values from the nomograph represented the 95th percen tile of residue values from actual field measurements (Hoerger and Kenega, 1972). For the purposes of this assessment, upperbound Kenaga nomogram estimates reported by T-REX are used for derivation of the EECs for the terrestrial-phase CRLF, SFGS, SMHM, BCB, VELB, SJKF, CTS and their potential prey.

Birds are currently used as surrogates for terrestrial-phase amphibians and reptiles. However, amphibians and reptiles are poik ilotherms (body temperature varies with environmental temperature) while birds ar e homeotherms (temperature is regulated, constant, and largely independent of envi ronmental temperatures). Therefore, amphibians and reptiles tend to have much lowe r metabolic rates and lower caloric intake requirements than birds or mammals. As a consequence, birds are likely to consume more food than amphibians and reptiles on a da ily dietary intake basis, assuming similar caloric content of the food items. Therefore, the use of avian food intake allometric equation as a surrogate to amphibi ans and reptiles is likely to result in an over-estimation of exposure and risk for rept iles and terrestrial-phase amphi bians. Therefore, T-REX (version 1.4.1) has been refine d to the T-HERPS model (v. 1.0), which allows for an estimation of food intake for poikilotherms us ing the same basic procedure as T-REX to
estimate avian food intake.

Because there is some evidence of the poten tial for bioaccumulation of endosulfan in aquatic organisms, an additional exposure pathway that will be considered in this assessment is the consumption of contaminated fish or aquatic invertebrates that have
bioaccumulated endosulfan dissolved in water an d their aquatic diet. The potential risk from this pathway will be evaluated and discussed further in the “Risk Description” section of the document. Multiple lines of evidence will be used to evaluate bioaccumulation potential, including measur ed bioconcentration factors (BCF), bioaccumulation factors (BAF) and a food web bioaccumulation model (Kow-Based Aquatic Bioaccumulation Model or KABAM). The bioaccumulation assessment relies on predicted water and sediment concentr ations from PRZM/EXAMS to estimate concentrations of endosulfan in aquatic organisms. These estimated tissue concentrations will be compared to toxicity values for va rious taxonomic groups that may eat aquatic organisms in order to ev aluate potential risk.

The potential for exposure of listed species through consumption of contaminated terrestrial prey will be evaluated by fugacity modeling for the earthworm based on predicted concentrations of endosulfan in soil and soil pore water using PRZM.

68

### Spray drift models, AGDISP and/or AgDRIFT ar e used to assess expos ures of terrestrial animals to endosulfan deposited on terrestrial habitats by spray drift. AGDISP (version 8.13; dated 12/14/2004) is used to simulate aerial and ground applications using the
Gaussian far-field extension. In addition to the buffered area from the spray drift analysis, the downstream extent of endosul fan that exceeds the LOC 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, SFGS, SMHM, BCB, VELB, SJKF, and CTS. Data were obtained from registrant submitted studies or from literature studies identified by ECOTOX. The ECOTOXicology database (ECOTOX) was search ed 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 a quatic life, terrestrial plants, and wildlife.
ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National Health and E nvironmental Effects Research Laboratory's Mid-Continent Ecology Division.

The assessment of risk for direct effects to the terrestrial-phase CRLF, CTS, and SFGS makes the assumption that toxicity of endosulfa n to birds is similar to or less than the toxicity to terrestrial-phase amphibians and reptiles (this al so applies to potential prey items). The same assumption is made for fish and aquatic-phase regarding direct effects on CRLF and CTS (again, this also a pplies to potential prey items).

The acute measures of effect used for animal s in this screening level assessment are the

LD 50 

### , LC 50 

### and EC 50 

### . LD stands for "Lethal Dose", and LD 50 

### 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 LC 50 

### is the concentration of a chemical that is estimated to kill 50% of the test organisms. EC stands for “Effective Concentration” and
the EC 50 

### 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 an d NOEC. NOAEL stands for “No
Observed-Adverse-Effect-Level” and refers to the highest tested dose of a substance that has been reported to have no harmful (adve rse) 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 statis tically different from the control. The
NOEC is the No-Observed-Effects-Concentra tion. For non-listed plants, only acute exposures are assessed ( i.e. , EC 25 

### for terrestrial plants and EC 50 

### for aquatic plants).

It is important to note that the measures of effect for direct and indirect effects to the assessed species and their designated critical habitat are associat ed with impacts to survival, growth, and fecundity, and do not incl ude the full suite of sublethal effects used to define the action area. According th e Overview Document (USEPA 2004), the Agency relies on effects endpoints that are ei ther direct measures of impairment of survival, growth, or fecundity or endpoints for which there is a scien tifically robust, peer

69

### reviewed relationship that can quantify the im pact 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 e ffects characterization to determine the potential ecolo gical risk from agricultural uses of endosulfan and the
likelihood of direct and indirect effect s to CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS in aquatic and terrestrial habitats. The exposure and toxic ity effects data are integrated in order to eval uate the risks of adverse eco logical effects on non-target species. For the assessment of endosulfan risks, the risk quotient (RQ) method is used to compare exposure and measured toxicity valu es. EECs are divided by acute and chronic toxicity values. For calculation of RQs for aquatic organisms, EECs for total endosulfan (sum of ά

, β , and endosulfan sulfate) were divided by the appropriate toxicity value for the TGAI (or in the case of se diment toxicity, endosulfan su lfate since acceptable data were only available for this degradate). Th e resulting RQs are then compared to the Agency’s levels of concer n (LOCs) (USEPA, 2004) (see Appendix D ).

For this endangered species assessment, listed species LOCs are used for comparing RQ values for acute and chronic exposures of endosulfan directly to the CRLF, SFGS, SMHM, BCB, VELB, SJKF, and CTS. If estim ated exposures directly to the assessed species of endosulfan resulting from a particul ar use are sufficient to exceed the listed species LOC, then the effects determinati on for that use is “may affect”. When considering indirect effects to the assessed species due to effects to prey, the listed species LOCs are also used. If estimated expos ures to the prey of the assessed species of endosulfan resulting from a particular use ar e sufficient to exceed the listed species LOC,
then the effects determination for that use is a “may affect.” If the RQ being considered also exceeds the non-listed species acute risk LOC, then the effects determination is a LAA. If the acute RQ is between the lis ted species LOC and th e non-listed acute risk species LOC, then further lines of evidence ( i.e . probability of individual effects, species sensitivity distributions) are considered in distinguishing between a determination of NLAA and a LAA. If the RQ being considered for a particular use exceeds the non-listed species LOC for plants, the effects determination is “may affect”. Specifically, any exceedances of the listed species LOC for dico ts would also result in an LAA for the BCB and VELB due to their obligate relations hip with dicots. Further information on LOCs is provided in Appendix D

.

2.10.2 Data Gaps

Data gaps were identified for several taxa fo r ecological effects. These include aquatic vascular plants, terrestrial monicots, and terres trial dicots. In addition, no data acceptable for quantitative use in this risk assessment was identified for amphibians (aquatic or terrestrial phases) and reptiles.

70

# 3 Exposure Assessment

Endosulfan is formulated as wettable pow der and emulsifiable concentrate and applied as liquid spray only. Application equipment includes various types of ground sprayers, airblast sprayers, and aerial spraye rs. Aerial application is permitted in all crops and therefore was chosen to evaluate exposure because aerial application gave the highest exposure because of higher spray drift levels Ground application is also considered for cotton as it gave higher e xposure values because it is applied at a higher rate than aerial application. Furt hermore, aquatic EECs for a range of ground application scenarios were ev aluated and found to be within a factor of two of those from the corresponding aerial ap plication scenario (most w ithin 20%). Risk quotients from the ground application scenario yielding the lowest EEC (Eggplant) did not change appreciably compared to the aerial application eggplant scenario and still
exceeded the acute and chronic LOCs for a quatic organisms. Terrestrial EECs and RQs calculated using T-REX and T-HERPS models do not dis tinguish ground spray from aerial application methods. Therefore, the risk profile from aerial application is expected to be applicable to that fo r ground spray applicatio ns, except for some reduction in the spray drift dist ance modeled using AgDRIFT.

3.1 Label Application Rates, Intervals and Buffers

Endosulfan labels may be categorized into two types: labels for manufacturing uses (including technical grade endosulfan and its formulated products) and end-use products. While technical products, which contain endosu lfan of high purity, are not used directly in the environment, they are used to make formulated products, which can be applied in specific areas to control insects. The formul ated product labels legally limit endosulfan’s potential use to only those sites that are spec ified on the labels. Us es being assessed are
summarized in Table 3.1

.

Table 3.1 Summary of labeled endosulfan uses, scenarios, and application information

Scenario Crop Represented Application Rate (lbs/A) Number of Applications Application Window (Interval) (first Application Date”dd-mm”)

CA almond Almonds, Hazelnuts &
Walnuts 2.00 1 01-02 to31-08 (NA) (07-02)

2.50 1

CA citrus Citrus 0.5+2.00 2 01-06 to 31-10 (10 days) (01-06) Broccoli, Cabbage &
Cauliflower 1.00 2
CA cole

crops Collards, Kale &
Mustard Green 0.75 1 30-01 to 31-08 (7 days) (13-02 for Broccoli and 27-03 for Collards)

CA corn Sweet corn for fresh market only 1.5 1 01-05 to 01-09 (NA) (15-05)

1.00 2 CA cotton Cotton (ground application) 0.50+1.50 2 01-06 to 01-09 (7 days) Mainly in September (15-06 same results as 01-09)



### 71Scenario Crop Represented Application Rate (lbs/A) Application Window (Interval) Number of Applications (first Application Date”dd-mm”)
Cotton (aerial application) 0.75 2

2.50 1

Apple 0.5+0.75+1.25 3 15-04 to 30-05 (10 days) (15-04)

2.50 1

CA fruits Apricot, Cherry, Nectarine, Peach, Pear, Plum & Prune 0.50+2.00 2 15-02 to 01-07 (10 days) (15-04)

CA lettuce Lettuce & Brussels Sprouts 1.00 2 01-02 to 01-04; and 15-09to 30-10 (5 days) (14-02)

1.00 2 Cucurbits (Cucumber, Melons, Pumpkin & Squash) 0.50+0.50+1.00 3 30-04 to 01-08 (7 days) (14-05)

0.50 1

CA melon Eggplant 0.25 2 01-05 to 31-07 (7 days) (15-05)

CA nursery Ornamentals or Shade
Trees 0.50 6 15-02 to 15-07 (10 days) (21-02)

1.00 2

Potato 0.50 4 01-04 to 01-10 (5 days) (14-04)

CA potato Sweet Potato 0.50 3 01-05 to 07-06 (5 days) (14-05) Beans & Peas (dry) & Pepper 1.00 2 01/07 to 01-08 (5 days) (15-07)

Carrot & Celery 1.00 1 CA row

crops Celery 0.50 2 01-03 to 01-10 (5 days) (15-03)

2.00 1 CA strawberry Strawberry 1.00 2 15-02 to 01-09 (15 days) (21-02)

1.00 2

CA tomato Tomato 0.50 4 01-04 to 30-07 (7 days) (15-04)



### In ecological exposure modeling the drift component is usua lly set to a default value of 5% (input parameters guidance, 2002). For endosulfan, the principal mitigation
measure for reduction of drift is a 300 ft . buffer from surface water bodies. This
buffer distance is the same for a ll types of applications in Ca lifornia. In order to arrive at an estimate for drift, AgDRIFT was used (a computer model of spray drift). For aerial application, AgDRIFT estimated drif t beyond the 300 ft buffer to be 2.38% for aerial and 0.15% for ground application ( Appendix B ).

72

### 3.2 Aquatic Exposure Assessment

3.2.1 Modeling Approach

Aquatic exposures are quantitatively estimated for all of assessed uses using scenarios that represent high exposure si tes for endosulfan use. Each of these sites represents a 10
hectare field that drains into a 1-hectare pond that is 2 mete rs deep and has no outlet. Exposure estimates generated using the sta ndard pond are intended to represent a wide variety of vulnerable water bodi es 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 standa rd surrogate pond. Stat ic 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. Thes e water bodies will be either shallower or have large drainage areas (or both). Shallow water bodies te nd to have limited additional storage capacity, and thus, tend to overflow a nd carry pesticide in the discharge whereas the standard pond has no discharge. As wa tershed size increases beyond 10 hectares, at some point, it becomes unlikely that the enti re 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 downstr eam. For uncertainties related to modeling EECs in estuarine/marine environments, refer the reader to the Section 6

.

Application of endosulfan is expected to re sult in movement of its isomers and common degradate into surface water by spray drift, run-off, and volatilization. For aquatic systems, estimated environmental concen trations (exposure EECs) are obtained by PRZM and EXAMS modeling which represen t EECs resulting from drift and runoff/erosion. Although volatilization is simulate d, as a loss, by PRZM, wet and dry redeposition, of this loss, into aquatic syst ems is not included in the EXAMS simulation and resultant EECs. For endosulfan, mode ling for EECs should include species that constitutes the multi-chemical stressor, α - and β -endosulfan and endosulfan sulfate (referred to in modeling as th e total toxic residues or TTR). Therefore, a method should be used to determine EECs for the TTR. Among the three methods suggested by EFED
to assess exposure to pare nt (here two parents) and degradation products, the SAP recommended the use of formation and decline kinetics (FD) and in some cases the Residue Summation (RS) or Total Residue (TR) methods (SAP, 2009) 16 

### . Currently, the FD method can not be used as it requires the use of EXPRESS she ll which is the only shell capable of facilitating the use of parent/daughter PRZM/EXAMS modeling
feature 17 

### . Therefore, the RS me thod was used to arrive at exposure EECs for α - and β

endosulfan and endosulfan sulfate separately and in total. The procedure is explained in

16 SAP (The FIFRA Scientific Adviso ry Panel). 2009. Minutes for the SAP Meeting on selected issues associated with risk assessment process for pes ticides with persistent, bio-accumulative and toxic characteristics. October 28-31, 2008. Arlington, VA. (Document No. 2009-01 dated Jan 29, 2009).

17 At the time of executing modeling, the EXPRESS shell was not formally approved and parent to daughter modeling feature of PRZM/EXAMS can not be utilized when PE-5 shell is used.



### 73

### detail in Appendix C . In summary, the method requires assignment of application rates for each of the three species of the stressor. These rates are included in Table 3.2 . The application rates for the indi vidual residues were normalized according to the percentage
of maximum residue detected in aerobic soil metabolis m studies and the molecular weight ratio of degradat e and parent compounds.

Table 3.2 Calculation of application rates for α - and β -endosulfan and endosulfan sulfate) for use in modeling (rates are for almond)

% Maximum in Aerobic Soil Study Chemical Species Observed Normalized Application Rate (kg/ha) Molecular
Ratio Required Application Rate (kg/ha)

Alpha 70% 45% 1.009 1 1.009

Beta 30% 19% 0.426 1 0.426

SO4 57% 36% 0.807 1.039 0.839

Total 157% 100% 2.242



### Example calculation given in Table 3.2 is for almonds which is a pplied at a single rate of 2 lbs a.i./A (2.242 kg a.i/ha). Rates used in the simulations were 1.009 kg a.i/ha of α - and 0.426 kg a.i/ha for β -endosulfan and 0.839 kg a.i/ha. A ll of the three chemicals were assumed to be applied at time zero. In this case, it is assumed that the maximum degradation of the two pare nts and the maximum formation of the common degradate occur at application. Three PRZM/EXAMS mo deling runs were executed using PE-5. The first modeling run gives 1- in-10 years exposure EECs for α -endosulfan, the second
for β -endosulfan, and the third for endosulfan su lfate. EECs for the total residue of concern, or the stressor, were calculated by combining daily concentrations from the three chemicals (refer to Appendix C for a complete example calculation).

Use-specific management practic es for all of the assessed uses of endosulfan were used for modeling, including application rates, num ber of applications per year, application intervals, and buffer widths and resulting spray drift valu es (modeled from AgDRIFT) and the first application date for each use. Date of first application was developed based
on several sources of information includi ng data provided by BE AD, a summary of individual applications from the CDPR PUR data, pesticide label (crop stage and pest), and Crop Profiles maintained by the USDA 18 

### . A sample of the distribution of endosulfan applications to selected crops in Appendix C based on CDPR PUR data for 2006.

18 

### URL: http://pestdata.ncsu.edu/cr opprofiles/cropprofiles.cfm

74

### Data from Appendix C was used to pick two applica tion windows for lettuce from early February to early April and from mid Septembe r to late October. In contrast, data in Appendix C for cotton indicates one major applicat ion window from late August to mid September.

3.2.2 Model Inputs

Environmental fate and transport and other da ta used for generating the parameters for
the three PRZM/EXAMS runs are listed in Table 3.3

.

Table 3.3 Summary of PRZM/EZAMS environmental fate and transport data of α - and β -endosulfan
and endosulfan sulfate used as aquatic exposure inputs for this endangered species assessment

Value*

Input Parameter 1 (Unit)

α -endosulfan β -endosulfan Endosulfan Sulfate

Molecular Weight g/mole 406.9 406.9 422.9

Henry’s constant ( atm-m 3 mol -1 @ 25 o C) 3.0E-6 1.4E-6 1.6E-5

Vapor Pressure ( torr @ 25 o C) 4.6E-5 2.4E-5 9.8E-6

Solubility in Water(mg/L) 0.53 0.28 0.33

Photolysis in Water (t1⁄2 in days @ pH 7) Stable Stable Stable

Aerobic Soil Metabolism (90 th % t1⁄2 in days) 57 208 Stable

Hydrolysis (90 th % t1⁄2 in days) 11 19 184
Aerobic Aquatic Metabolism (water column t1⁄2 in days) 2 114 416 Stable Anaerobic Aquatic Metabolism (benthic t1⁄2 in days) 3 230 298 286

K
oc (Average in ml/g) 10,600 13,500 12,050 4

Application rate and frequency Application intervals Depends on the crop (refer to Table 3.2 for an example)

Chemical Application Method (CAM) 2

Application Efficiency 95% for aerial and 99% for ground

Spray Drift Fraction 1 0.024 for aerial and 0.002 for ground

* Source of data refer to Table 2.1 and Table 2.2 in the environmental fate properties section above

1 Inputs determined in accordance with EFED “Guidance for Chemistry and Management Practice Input Parameters for Use in Modeling the Environmental Fate and Tran sport of Pesticides” dated February 28, 2002

2 Estimated 2 X aerobic soil metabolism half-life;

3 Estimated 2 X anaerobic soil metabolism half-life

4 Assumed to be equal to the average for its parents= 10,600 ml/g and 13,500 ml/g= 12,050 ml/g



### 75

### PRZM/EXAMS simulation involved execution of three runs, the first run for α

endosulfan, the second run is for β -endosulfan, and the third run for endosulfan sulfate.

3.2.3 Results

Aquatic EECs

The aquatic EECs for the various scenarios and application practices are listed in
Table 3.4 and Table 3.5 . The first table contains aqua tic exposure EECs resulting from
the first and second run while the second table contains EECs resulting from the third run and the post processed EECs for the total stre ssor from results of the three runs. An example of how the combined EECs were estimated is presented in Appendix C . In summary, the process includes combining daily EECs (simple addition for daily concentrations) followed by calculating th e 1-in-10 year averages using the 90 th 

### percentile procedure. Although more than one run was executed for some crops, the
more conservative results were chosen. For example, citrus was simulated at 2.5 lb a.i/A with one application and 0.50+2.00 lbs a. i. /A in two applications. In
Table 3.4 and Table 3.5 , the highest exposure EEC values were chosen.

Table 3.4 Aquatic EECs ( μ g/L) for endosulfan used in California ( α - and β -endosulfan) 1

α -endosulfan β -endosulfan Crop Run No.* Peak 21-day 60-day Peak 21-day 60-day

Almonds, Hazelnuts & Walnuts 1 1.44 0.402 0.213 0.60 0.143 0.079

Citrus 1 1.50 0.371 0.181 0.63 0.127 0.062
Broccoli, Cabbage & Cauliflower 1 1.21 0.553 0.345 0.55 0.231 0.151
Collards, Kale & Mustard Green 2 0.70 0.247 0.136 0.30 0.101 0.056
Sweet corn for fresh market only 1 0.92 0.259 0.141 0.41 0.118 0.069
Cotton (ground) 2 0.39 0.199 0.162 0.22 0.083 0.067
Cotton (aerial) 3 0.67 0.310 0.206 0.27 0.112 0.079

All fruit trees 1 1.50 0.413 0.204 0.63 0.142 0.072
Lettuce & Brussels Sprouts 1 1.40 0.585 0.356 0.76 0.258 0.159

Cucurbits 1 0.86 0.429 0.249 0.31 0.114 0.064
Eggplant 3 0.30 0.076 0.037 0.13 0.029 0.016
Ornamentals or Shade Trees (Southern Coast) 1 2.24 0.704 0.427 1.19 0.294 0.174

Ornamentals or Shade Trees (Northern Central coast)) Add 1.95 0.682 0.489 1.02 0.321 0.207

Potato 1 0.87 0.322 0.208 0.34 0.109 0.074
Potato (Northern Central coast) Add 1.18 0.410 0.208 0.49 0.162 0.102

Sweet Potato 3 0.55 0.258 0.150 0.21 0.089 0.052
Beans & Peas (dry) & Pepper 1 0.81 0.292 0.148 0.33 0.110 0.059
Carrot & Celery 2 0.63 0.186 0.110 0.27 0.072 0.045
Strawberry 1 1.27 0.520 0.311 0.59 0.209 0.137

Tomato 1 0.77 0.309 0.165 0.31 0.111 0.060

1 aerial application is used in runs for all crops. For cotto n, an additional run is shown for ground application because ground application to cotton is at a high er rate compared to aerial application. * Add= an additional run using weather station to represent crop growing in areas different than the default areas assigned



### 76α -endosulfan β -endosulfan Crop Run No.* Peak 21-day 60-day Peak 21-day 60-day
by the scenario.

Table 3.5 Aquatic EECs ( μ g/L) for endosulfan used in California (endosulfan sulfate and total stressor)

Endosulfan Sulfate Total (as parent) Crop Run No.* Peak 21-day 60 day Peak 21-day 60 day

Almonds, Hazelnuts & Walnuts 1 1.41 0.483 0.329 3.35 1.026 0.617

Citrus 1 1.27 0.344 0.186 3.35 0.900 0.444
Broccoli, Cabbage & Cauliflower 1 3.82 1.742 1.250 4.81 2.603 1.757
Collards, Kale & Mustard Green 2 1.22 0.515 0.367 1.67 0.775 0.501
Sweet corn for fresh market only 1 2.60 0.897 0.658 2.88 1.137 0.774
Cotton (ground) 2 0.73 0.354 0.287 1.24 0.596 0.521
Cotton (aerial) 3 0.66 0.357 0.284 1.56 0.824 0.593

All fruit trees 1 1.33 0.434 0.242 3.40 1.013 0.532
Lettuce & Brussels Sprouts 1 4.86 1.845 1.381 5.88 2.575 1.854

Cucurbits 1 1.19 0.490 0.370 1.55 0.815 0.613
Eggplant 3 0.35 0.122 0.092 0.72 0.237 0.131
Ornamentals or Shade Trees (Southern Coast) 1 2.14 0.744 0.484 3.43 1.357 1.004
Ornamentals or Shade Trees (Northern Central coast)) Add 1.82 0.645 0.456 4.38 1.728 1.130

Potato 1 0.74 0.313 0.202 1.89 0.770 0.492
Potato (Northern Central coast) Add 1.01 0.413 0.270 2.63 1.011 0.561

Sweet Potato 3 0.49 0.233 0.151 1.18 0.622 0.358
Beans & Peas (dry) & Pepper 1 1.59 0.561 0.384 2.00 0.851 0.508
Carrot & Celery 2 1.55 0.499 0.437 1.72 0.735 0.538
Strawberry 1 2.27 1.054 0.750 3.64 1.714 1.108

Tomato 1 0.78 0.375 0.227 1.79 0.808 0.450

* Add= an additional run using weather station to represent crop growing in areas different than the default areas assigned by the scenario.



### For total stressor, the highest EECs are asso ciated with lettuce for the peak (5.88 ppb), non-leafy cole crops for the 21-day average ( 2.60 ppb) and lettuce for the 60-day average (1.85 ppb). In contrast, the lowe st EECs for all time averages are for eggplant (peak= 0.72 ppb, 21-day= 0.24 ppb, and 60-day= 0.13 ppb). Data suggest that exposure is the highest for lettuce and non-leafy cole crops (peak range= 3.43-5.88 ppb), followed by Strawberry, fruit/nut trees, citrus, and potatoes grown in the northern part of the central coast (peak range from 2.0 to 3.43 ppb), and al l other crops except e ggplant (1.18 to 1.89 ppb). Eggplant has the lowest exposure EECS (<1 ppb).

As expected, the major cont ributor to exposure is endos ulfan sulfate (53% on the average) followed by α -endosulfan (34% on the average), and β -endosulfan (14% on the average). The results reflect the isomer ratio (70 % for α -endosulfan and 30% for by β

endosulfan) and persistence of the co mmon degradate endosulfan sulfate.

77

### Exposure to sediment pore water in aquatic sy stems was also obtained for the same runs,
this data are listed in Table 3.6 and Table 3.7

.

Table 3.6 Sediment pore water EECs ( μ g/L) for endosulfan used in California ( α - and β -endosulfan)

α -endosulfan β -endosulfan Crop Run No.* Peak 21-day 60-day Peak 21-day 60-day

Almonds, Hazelnuts & Walnuts 1 0.11 0.110 0.108 0.05 0.046 0.045

Citrus 1 0.09 0.093 0.086 0.03 0.032 0.030
Broccoli, Cabbage & Cauliflower 1 0.22 0.214 0.203 0.11 0.107 0.102
Collards, Kale & Mustard Green 2 0.08 0.083 0.079 0.04 0.036 0.034
Sweet corn for fresh market only 1 0.08 0.082 0.076 0.05 0.051 0.047
Cotton (ground) 2 0.10 0.097 0.095 0.05 0.046 0.045
Cotton (aerial) 3 0.10 0.105 0.102 0.04 0.043 0.042

All fruit trees 1 0.11 0.105 0.098 0.04 0.041 0.038
Lettuce & Brussels Sprouts 1 0.22 0.219 0.207 0.11 0.104 0.098

Cucurbits 1 0.14 0.134 0.127 0.04 0.038 0.035
Eggplant 3 0.02 0.020 0.018 0.01 0.009 0.009
Ornamentals or Shade Trees (Southern Coast) 1 0.33 0.323 0.302 0.13 0.131 0.122

Ornamentals or Shade Trees (Northern Central coast)) Add 0.35 0.345 0.328 0.15 0.147 0.139

Potato 1 0.10 0.100 0.094 0.04 0.036 0.034
Potato (Northern Central coast) Add 0.11 0.110 0.104 0.07 0.068 0.064

Sweet Potato 3 0.08 0.075 0.070 0.03 0.027 0.025
Beans & Peas (dry) & Pepper 1 0.08 0.082 0.077 0.04 0.039 0.038
Carrot & Celery 2 0.06 0.063 0.060 0.03 0.027 0.026
Strawberry 1 0.17 0.166 0.158 0.08 0.080 0.076

Tomato 1 0.08 0.083 0.077 0.03 0.033 0.031

* Add= an additional run using weather station to represent crop growing in areas different than the default areas assigned by the scenario

Table 3.7 Sediment pore water EECs ( μ g/L) for endosulfan used in California (endosulfan sulfate and total stressor)

Endosulfan Sulfate Total (as parent)** Crop Run No.* Peak 21-day 60 day Peak 21-day 60 day

Almonds, Hazelnuts & Walnuts 1 0.22 0.215 0.213 0.37 0.363 0.357

Citrus 1 0.10 0.101 0.095 0.23 0.222 0.207
Broccoli, Cabbage & Cauliflower 1 0.89 0.881 0.850 1.18 1.168 1.123
Collards, Kale & Mustard Green 2 0.27 0.265 0.261 0.38 0.375 0.365
Sweet corn for fresh market only 1 0.39 0.390 0.383 0.51 0.508 0.492
Cotton (ground) 2 0.21 0.208 0.206 0.35 0.344 0.339
Cotton (aerial) 3 0.18 0.183 0.181 0.33 0.324 0.319

All fruit trees 1 0.16 0.158 0.150 0.30 0.298 0.280
Lettuce & Brussels Sprouts 1 0.90 0.892 0.873 1.19 1.181 1.145

Cucurbits 1 0.26 0.254 0.242 0.42 0.416 0.394
Eggplant 3 0.06 0.064 0.060 0.09 0.090 0.085
Ornamentals or Shade Trees (Southern Coast) 1 0.35 0.352 0.341 0.80 0.793 0.753



### 78Endosulfan Sulfate Total (as parent)** Crop Run No.* Peak 21-day 60 day Peak 21-day 60 day

Ornamentals or Shade Trees (Northern Central coast)) 1 Add 0.35 0.346 0.332 0.84 0.825 0.786

Potato 1 0.11 0.113 0.110 0.25 0.245 0.234
Potato (Northern Central coast) 1 Add 0.20 0.198 0.189 0.37 0.369 0.351

Sweet Potato 3 0.08 0.082 0.078 0.18 0.181 0.170
Beans & Peas (dry) & Pepper 1 0.28 0.279 0.267 0.39 0.390 0.373
Carrot & Celery 2 0.31 0.304 0.290 0.39 0.382 0.364
Strawberry 1 0.49 0.484 0.466 0.72 0.712 0.682

Tomato 1 0.17 0.163 0.155 0.28 0.274 0.257 * Add= an additional run using weather station to represent crop growing in areas different than the default areas assigned by the scenario ** Important Note: This total is a product of simple addition of the 1-10 year data and was not calculated from combining daily concentrations (currently PE-5 do not produc e a file containing daily concentrations for the pore water)



### Exposure to benthic sediment in aquatic system s was also obtained for selected runs, this
data are listed in Table 3.8 and Table 3.9

.

Table 3.8 Sediment EECs ( μ g/L) for endosulfan used in California ( α - and β -endosulfan)

α -endosulfan β -endosulfan Crop Run No. Peak 21-day 60-day Peak 21-day 60-day

Broccoli, Cabbage & Cauliflower 1 92 91 86 59 58 55
Cotton (aerial) 3 45 44 43 24 23 23

All fruit trees 1 45 45 42 22 22 20
Lettuce & Brussels Sprouts 1 94 93 88 57 56 53
Eggplant 3 9 8 8 5 5 5
Ornamentals or Shade Trees (Southern Coast) 1 139 137 129 72 71 66 Strawberry 1 71 70 67 44 43 41

Tomato 1 36 35 33 18 18 17

Table 3.9 Sediment EECs ( μ g/L) for endosulfan used in California (endosulfan sulfate and total stressor)

Endosulfan Sulfate Total (as parent)* Crop Run No. Peak 21-day 60 day Peak 21-day 60 day

Broccoli, Cabbage & Cauliflower 1 429 424 410 580 573 551
Cotton (aerial) 3 89 88 88 158 155 154

All fruit trees 1 77 76 72 144 143 134
Lettuce & Brussels Sprouts 1 434 430 422 585 579 563
Eggplant 3 31 31 29 45 44 42
Ornamentals or Shade Trees (Southern Coast) 1 171 170 165 382 378 360
Strawberry 1 235 233 225 350 346 333

Tomato 1 80 79 75 134 132 125 * Important Note: This total is a product of simple addition of the 1-10 year data and was not calculated from combining daily concentrations (currently PE-5 do not produce a file containing daily concentrations for the pore water)



### 79

### Bioaccumulation Assessment

Considering that log K OW 

### values for the parent endosulfan isomers and endosulfan sulfate either approach or exceed a log Kow of 4, and that endosulfan can persist for relatively long periods of time in aquatic ecosystems, the potential for direct effects on aquaticphase CRLF through consumption of contaminat ed aquatic prey was investigated. The KABAM model (K OW 

### (based) Aquatic BioAccumulation Model) version 1.0 was used to evaluate the potential exposure and risk of direct effects to aquatic-phase CRLF via bioaccumulation and biomagnification in a quatic food webs. KABAM is used to estimate potential bioaccumul ation of hydrophobic organic pe sticides in freshwater aquatic ecosystems and risks to mammals and birds consuming aquatic organisms which have bioaccumulated these pesticides. The bioaccumulation portion of KABAM is based upon work by Arnot and Gobas (2004) who parameterized a bioaccumulation model based on PCBs and some pesticides (e .g., lindane, DDT) in freshwater aquatic ecosystems. KABAM relies on a chemical's octanol-water partition coefficient (K OW 

### ) to estimate uptake and elimination constants through respiration and diet of organisms in different trophic levels. Pesticid e tissue residues are calculated for different levels of an aquatic food web. The model then uses pesticide tissue concen trations in aquatic animals to estimate dose- and dietary-based exposures and associated risks to mammals and birds consuming aquatic organisms. Previous anal yses using an earlier version of the KABAM model indicate relatively clos e agreement between its predic ted bioconcentration factor (BCF) and those reported from experiment al studies for endosulfan (USEPA 2007; D346213).

Details of the bioaccumulation assessment fo r endosulfan in relation to the CRLF are provided in Section 5.2.1.1

.

Soil EECs

Total soil and pore water concentrations were calculated using PRZM simulations for selected crop scenarios. Crop scenario s were selected to include a range of concentrations based on aqua tic exposure EECs obtained for endosulfan use patterns. Two PRZM runs were executed for six crop us e patterns, one for aerial application and the other for ground application. Results are summarized in Table 3.10 which includes results for the ground applications only. Concentrations for aerial applications are not
included because values were either similar or slightly less. It is noted that total soil and soil pore water concentrations are represented by either the highest or the steady state
values. These values are obtaine d from plots of the total st ressor daily concentrations
similar to those included in Figures C-1 & C-2 (Appendix C) for the total soil
concentration and Figures C-3 & C-4 (Appendix C) for the soil pore water
concentration. Figures C-1 to C-4 suggest the following for to tal stressor concentration in the soil system: (1) Concentration is determined by endosulfan sulfate because concentrations for the other two endosulfan species (alpha & beta ) appear to reach st eady state (at very low concentrations), rather quickly; and

80

### (2) Concentration does reach steady state for only two use patterns: cotton and nursery ( Figures C-1 & C-3 ) while steady state is not reached for the others ( Figures C-2 & C-4 ).

Table 3.10 Total soil and pore water concentrations for selected crop scenarios

Total Soil Concentration Soil Pore Water Concentration

Crop Bulk Density (kg/ m 3 )* (mg/kg)* (mg/ m 3 )** (mole/ m 3 )** (mg/L)* (mg/ m 3 )** (mole/ m 3 )** Concentration
Reached Steady State?

Fruits 1.70 13.20 22,400 0.055 0.182 182 0.000447 No Cole crops 1.50 14.00 21,000 0.052 0.067 67 0.000165 No

Lettuce 1.58 12.00 18,600 0.046 0.140 140 0.000344 No Nursery 1.55 9.80 15,190 0.037 0.181 181 0.000445 Yes

Cotton 1.45 4.61 6,685 0.016 0.130 130 0.000319 Yes Eggplant 1.45 3.59 5,206 0.013 0.066 66 0.000161 No

* Bulk density from scenario for the top horizon (Top 10 cm); concentrations from PEZM simulation. ** Calculated values based on bulk density and molecular weight of endosulfan= 406.9 g/mole



### 3.2.4 Existing Monitoring Data

A critical step in the process of characteri zing EECs is comparing the modeled estimates with available monitoring data. Varied type s of monitoring data ex ist for alpha and beta endosulfan and the common degradate endos ulfan sulfate. Data cover important environmental compartments including surface water, ground water, sediment, and air.
Included in this assessment are endosulfa n data from the USGS NAWQA program, the EPA STORET, and the California Department of Pesticide Regulation (CDPR).

3.2.4.1 Surface Water Monitoring Data

CDPR Data
Surface water was monitored from 1991 to 2006 for α - and β -endosulfan and/or endosulfan sulfate in thirty three counties in California (Calif ornia Department of Pesticide regulations; CDPR) 19 

### . Reported data show relatively high frequency and concentrations from 1991 to 1996 particularly for Imperial County. In contrast, significantly lower frequency and concentratio ns were observed in data collected from 2001 to 2006 for the three species ( Figure 3.1 ) and their total ( Figure 3.2 ).

19 California Department of Pesticide Regulations (CDPR) data was obtained from URL:http://www.cdpr.ca.gov/doc s/emon/surfwtr/surfcont.htm http://www.cdpr.ca.gov/docs /emon/grndwtr/list_mon.htm (GW no data) http://www.cdpr.ca.gov/docs/emon/pubs/tac/endoslfn.htm (Air)



### 81Figure 3.1 Detected concentrations of alpha and beta-endosulfan and common degradate in
California surface waters from 1991 to 2006 (No data were collected from 1996 to 2000).

Out of scale values were for SO4 only. These values occurred on 6/21/1993 and were: 0.562, 0.485, and 0.378 ppb 0 0.02 0.04 0.06 0.08

0.1 0.12 0.14 0.16 0.18

0.2

Jan90 Jan91 Jan92 Dec92 Dec93 Dec94 Dec95 Dec96 Dec97 Dec98 Dec99 Dec00 Dec01 Dec02 Dec03 Dec04 Dec05 Monitoring DateMonitred Concentration (ppb) Alpha-endosulfan Beta-endosulfan endosulfan sulfate

Figure 3.2 Detected concentrations of the total endosulfan species in California surface waters from
1991 to 2006

Out of scale values occurred on 6/21/1993 and were 0.952, 0.825 & 0.495 ppb 0.0000 0.0500 0.1000 0.1500 0.2000 0.2500 0.3000

Jan90 Jan91 Jan92 Dec92 Dec93 Dec94 Dec95 Dec96 Dec97 Dec98 Dec99 Dec00 Dec01 Dec02 Dec03 Dec04 Dec05 Monitoring DateMonitred Concentration (ppb) Endosulfan Species Total



### In interpreting the data, the following should be taken in consideration:

82

### (1) Not all endosulfan species were determ ined for all the samples suggesting that
observed total residue concentrations c ould be higher than that displayed in Figure 3.2
above. (2) Reported detection limits for α - and β -endosulfan were mostly 0.005 ppb while it ranged from 0.01 to 0.005 ppb for the common endosulfan sulfate degradate ( Table
3.11 ).

Table 3.11 Summary of reported detection limits for th e CDPR surface water data

Proportion of Samples Analyzed at the Detection limit (in %) Samples With Detections Samples Without Detections Reported
Detection Limit (ppb) alpha Beta SO4 alpha Beta SO4

0.0001 2% 0% 1% 1% 6% 6%

0.002 NA NA 5% NA NA 11%

0.001 0% NA NA 10% NA NA

0.005 98% 100% 50% 74% 70% 29%

0.01 NA NA 44% NA NA 54%

0.1 0% 0% NA 15% 24% NA

(NA= Not Applicable)



### (3) During the first monitoring period (1991 to 1996), nearly 2,000 surface water samples
were collected from 83 sites in nine counties. In contrast, only 500 surface water samples
were collected from 153 s ites in 24 counties during the second monitoring period.

(4) During the second monitoring period, sampling was repeated for 7 counties, namely, Imperial, Merced, Sacramento, San Joa quin, Sonoma, Stanislaus, and Sutter.

(5) During the second period rates and uses were reduced.

For the first monitoring period, data are summarized in Table 3.12 . In interpreting this data, it is important to note the following:

• Endosulfan sulfate were determined for nearly 93% of the samples;

• α - and β -endosulfan were determined for only 31% of the samples; and

• All of the three species were determ ined for only 26% of the samples.

Table 3.12 Summary of CPDR surface water monito ring data for California Counties collected for
the first monitoring period (1991 to 1996)

Total Number of Detection Distribution County Monitoring Years Sites Samples Detect No Detect Imperial 93- 94 11 195 64% 36%

Merced 91- 95 10 381 2% 98% Monterey 94- 95 6 213 0% 100%

Sacramento 90- 92 & 94- 96 11 566 <1% >99% San Joaquin 91- 93 2 51 4% 96%

Santa Cruz 94- 95 4 24 0% 100%

Sonoma 94- 95 2 153 0% 100%
Stanislaus 91- 93 10 76 8% 92%

Sutter 93- 94 1 153 0% 100%



### 83

### Data in Table 3.12 indicate that at least one of th e endosulfan species was observed in
surface waters from five out of the nine counties including Imperial (64%) followed by Stanislaus (8%), San Joaquin (4%), Merced (2 %), and Sacramento (<1%). A summary of
all data is included in Figure 3.3 for Imperial County and Figure 3.4 for Stanislaus, San Joaquin, Merced, and Sacramento Counties.

Figure 3.3 CPDR Monitoring data for Imperial County (11 site s, varied times of the year)

0 0.025 0.05 0.075

0.1 0.125 0.15 0.175

0.2 0.225C oncentration (ppb)

1 2 3 4 5 6 7 8 91 0 1 1
Sampling Sites: All in Imperial County Alpha Endosulfan Beta Endosulfan Sulfate

Out of scale values are: 0.56 ppb fo r 1; 0.39 ppb for 2 and 0.49 ppb for 3



### 84Figure 3.4 CDPR Monitoring data fo r Merced County (4 sites), Stan islaus County (6 sites), San Joaquin County (2 sites) and Sacramento County (1 site) at varied times of the year

0 0.025

0.05 0.075

0.1 0.125

0.15 0.175

0.2C oncentration (ppb)

ME 1 2 3 4 S T 1 2 3 4 5 6 SJ 1 2 SA
Samplind Sites: (Merced=ME 1-4; Stanislaus=ST 1-6; San Joaquin= SJ 1-2; and Sacramento=SA Alpha Endosulfan Sulfate Beta Endosulfan



### Observed ranges of concentrations were the highest for the common degradate endosulfan sulfate (0.02 to 0.56 ppb) followed by α - and β -endosulfan (0.005 to 0.22 and 0.005 to 0.17 ppb, respectively). Total endosu lfan residue ranged from 0.03 to 0.95 ppb.

For the second monitoring period (2001 to 2006), mon itoring data are summarized in
Table 3.13

.

Table 3.13 Summary of CPDR surface wate r monitoring data for California (the 2 nd monitoring period)

Total Number Of: Detection Distribution (%) Species Analyzed For*

County Monitoring
Years Sites Samples Detect No Detect Beta

Alameda 01& 02 2 4 0% 100% No
Del Norte 02& 03 1 4 0% 100% No
Glenn 06 2 16 0% 100% Yes
Humboldt 02& 03 6 20 0% 100% No

Kern 06 2 4 0% 100% Yes Imperial *** 02- 04 12 67 9% 91% No
Lake 06 1 4 0% 100% Yes Los Angeles ** 01& 03 30 62 3% 97% No
Marin 01& 02 2 4 0% 100% No
Mendocino 02& 03 3 17 0% 100% No Napa 02 1 1 0% 100% No Orange 02& 03 8 36 0% 100% No
Merced*** 06 1 1 0% 100% No



### 85Total Number Of: Detection Distribution (%) Species Analyzed For* Monitoring County Years Sites Samples Detect No Detect Beta

Riverside 02- 04 8 28 0% 100% No
Sacramento*** 05- 06 1 18 0% 100% No
San Bernardino 02- 04 3 9 0% 100% No San Diego 02- 04 37 111 0% 100% No San Joaquin*** 04- 05 2 22 0% 100% No

San Mateo 02& 03 6 18 0% 100% No
Santa Clara 02& 03 3 12 0% 100% No
Shasta 06 1 2 0% 100% Yes Siskiyou 02& 03 9 42 0% 100% No
Solano 05& 04 4 33 0% 100% Yes
Tehama 06 1 2 0% 100% Yes Trinity 02& 03 2 8 0% 100% No
Tulare 05& 06 12 58 0% 100% Yes

Sonoma*** 02- 03 5 35 0% 100% No
Stanislaus*** 04 1 2 0% 100% Yes

Sutter*** 06 4 22 0% 100% Yes

Ventura ** 01 4 7 86% 14% No
Yolo 05& 06 5 78 0% 100% Yes Overall Summary 153 580 3% 97% Yes= 30%

* α - endosulfan was not determined for all samples; β -endosulfan as indicated in the Table by Yes= determined or No= not determined, and 100% of th e samples were analyzed for endosulfan sulfate ** These two counties were the location of the only six samples with endosulfan sulfate detections (samples were analyzed for endosulfan sulfate only). Concentrations were: 0.003 to 0.005 ppb from three locations in Los Angeles County; and 0.002 to 0.005 ppb from two locations in Ventura County *** Counties in which sampling is a repeat (i.e., these counties were also sampled during the first period)



### Data for the second monitoring period indica te two important points:

(1) For all counties: observed fre quency of detection and range s of concentrations were very low compared to earlie r years (1991 to 1996). In fact the only five detections were reported for samples collected in 2001 w ith endosulfan sulfate concentrations in the range of 0.002 to 0.005 ppb ( α - and β -endosulfan were not determined). Again,
endosulfan sulfate were determined for nearly 100% of the samples, α - and β

endosulfan were determined for only 0% a nd 30% of the samples, respectively; and (2) For Imperial, Stanislaus, San Joaquin, and Merced Counties: Second monitoring (2002 to 2006) showed a signi ficant decrease from the fi rst monitoring in earlier years. During these recent years, detecti ons were recorded in Imperial County only (9% of the samples) with no detections in Stanislaus, San Joaquin, and Merced
Counties.

EPA STORET Data
In STORET 20 

### , data are reported on monitored surface water from 2001 to 2008 (mostly from 2001 to 2003), for α - and β -endosulfan and/or endosulfa n sulfate in twenty one counties in California ( Table 3.14 ).

20 STORET Data base URL: http://www.epa.gov/storet/dw_home.html



### 86Table 3.14 Summary of ST ORET surface water monitori ng data for California

Total Number Of: Detects Distribution (%) County Monitoring month- Year Sites Samples >LOQ <LOQ Total

Alameda Sep-01; Apr-02 2 6 33% 0% 33%

Contra Costa Sep-01; Apr & Jun-02 2 5 0% 0% 0%

Del Norte Feb, Mar & Jun-02 3 8 0% 13% 13%

Humboldt Feb, Mar & Jun-02 3 5 0% 60% 60% Imperial May, Sep & Oct-02 20 44 0% 0% 0% Los Angeles Oct & Nov-01; Jan- 03 4 10 40% 0% 40%

Marin Oct-01; Apr-02 3 4 0% 0% 0%

Mendocino Feb, Mar & Jun-02 3 10 0% 30% 30% Napa 39966 1 1 0% 0% 0% Orange Oct-02; Jan, Apr & May-03 10 38 0% 18% 18%

Riverside May, Sep & Oct-02; Apr & May-03 7 13 0% 0% 0%
San Bernardino May & Oct-02 3 6 0% 0% 0%
San Diego Mar, Apr, Jun & Sep-02; Jan, Apr & May-03 15 70 9% 7% 16% San Luis Obispo Jul-03; Jan & July-04/05/06/07 & Jan-08 1 20 0% 0% 0%

San Mateo Apr & Jun-02; Jan-03 4 15 0% 0% 0%
Santa Barbara Jun-06; Jan-08 3 6 0% 0% 0%
Santa Clara Apr & Jun-02; Jan-03 4 13 0% 0% 0% Siskiyou Feb, Mar & Jun-02 2 6 0% 33% 33%
Solano Oct-01; Apr & Jun-02 2 3 0% 0% 0%

Sonoma Feb, Mar, Apr & Jun-02 3 15 0% 33% 33%

Ventura Nov-02 5 6 50% 0% 50%

Overall Summary 100 304 6% 9% 16%



### Reported data show relatively low frequency and concentrat ions. At least one of the endosulfan chemical species was detected with an overall frequency of 6% for detections over the LOQ, and 9% for detections below the LOQ. Observed concentrations are
shown in Figure 3.5 for all data/individual endosulfan species, Figure 3.6 for all data/total endosulfan species, and Figure 3.7 for data from counties with concentrations over the limit of quantification.

87Figure 3.5 Detected concentrations of α - and β -endosulfan and endosulfan sulfate common degradate in California surface waters from 2001 to 2008 (STORET data)

0.000 0.002 0.004 0.006 0.008 0.010

Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08

Monitoring DateConcentration (ppb) Alpha Beta SO4

Data points >0 and <0.002 represent samples with detec tions over the LOD but lower than the LOQ. These were assumed to equal 0.001 ppb because LOD and LOQ were no t reported. However, data suggest that the LOQ is probably equal to 0.002 ppb.

Figure 3.6 Detected concentrations of the total endosulfan species in California surface waters from 2001 to 2008 (STORET data)

0.000 0.002 0.004 0.006 0.008 0.010

Jan-01 Jan-02 Jan-03 Jan-04 Jan-05 Jan-06 Jan-07 Jan-08

Monitoring DateConcentration (ppb) Endosulfan Species Total

Data points >0 and <0.002 represent samples with detec tions over the LOD but lower than the LOQ. These were assumed to equal 0.001 ppb because LOD and LOQ were not reported. However, data suggest that the LOQ is probably equal to 0.002 ppb.



### 88Figure 3.7 Detected concentrations of α - and β -endosulfan and endosulfan sulfate common degradate in surface waters of five California Counties (Counties with detections over the LOQ; 2001 to 2008 STORET data)

0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009Concentration (ppb)

Alameda San Diego San Diego Los Angeles Ventura

Counties with Detections Over LOQ Alpha

Beta

SO4

(1) Data points >0 and <0.002 represent samples with detections over the LOD but lower than the LOQ. These were assumed to equal 0.001 ppb because LOD and LOQ were not reported. However, data suggest that the LOQ is probably equal to 0.002 ppb. (2) Samples with no detect are not included. The number of samples with no detects is equal to: 4 for Alameda Co.; 58 for San Diego CO.; 6 for Los Angeles Co. & 3 for Ventura Co.



### STORET data appear to be comparable to date reported by CDPR for the years following 2001. For these years, STORET data reported maximum concentrations 0.008 ppb for α endosulfan, 0.0064 ppb for β -endosulfan, 0.005 ppb for endosulfan sulfate, and 0.008 ppb for the total ( Figure 3.5 and Figure 3.6 ). For the same period, CDPR data reported the
same maximum concentrations of 0.005 ppb for endosulfan sulfate ( α - and β -endosulfan were not determined).

USGS NAQWA Data California surface water was monitored by the NAWQA program 21 

### during 1995 and from 2001 to 2007 for endosulfan residue including α -, β -, ether- endosulfan, and
endosulfan sulfate in fifteen sites in five c ounties. A total of nearly 200 samples were collected with no detection reported for any of the endosulfan residue including ether- endosulfan, and endosulfan sulfate. Detection limits varied for the various endosulfan residues: 0.0047 to 0.011 ppb for α -endosulfan, 0.0142 for β -, endosulfan 0.0041to 0.0066 ppb for ether- endosulfan, and 0.0058 to 0.022 ppb for endosulfan sulfate ( α -, β -,

,

Table 3.15 ).

Table 3.15 A summary of NAWQA monitoring data for surface water from California

Sampling Dates Endosulfan Species Detection Limits (ppb) County Site Start Finish Number of Samples Alpha Beta Ether SO4

Site 1 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND Merced

Site 2 9-Oct-01 27-Apr-05 23 0.0047 0.0142 0.0041 0.0058

21 NAQWA data was obtained on January 17, 2008: URL: http://infotrek.er.usgs.gov/traver se/f?p=NAWQA:HOME:3748645897450568



### 89Sampling Dates Endosulfan Species Detection Limits (ppb) County Site Start Number of
Finish Alpha Beta Ether SO4 Samples

22-Jun-05 15-Feb-06 5 0.0047 ND ND 0.0138 12-Apr-06 9-Aug-06 3 0.0110 ND ND 0.0220

13-Jun-05 7-Feb-06 5 0.0047 ND ND 0.0138

21-Jun-06 21-Jun-06 1 0.0110 ND ND 0.0122

Riverside Site 1 20-Apr-06 6-Sep-07 20 0.0110 ND ND 0.0220

15-Jun-05 27-Oct-05 7 0.0047 ND ND 0.0138

22-Nov-05 15-Mar-06 8 0.0047 ND ND 0.0138

Site 1 25-Apr-06 24-Sep-07 26 0.0110 ND ND 0.0220

16-Jun-05 28-Sep-05 8 0.0047 ND ND 0.0138

31-Oct-05 31-Oct-05 1 0.0047 ND ND ND

31-Oct-05 31-Oct-05 1 ND ND ND 0.0200

7-Dec-05 23-Feb-06 2 0.0047 ND ND 0.0138

Sacramento Site 2 27-Apr-06 2-Aug-06 3 0.0110 ND ND 0.0220

10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

16-Oct-02 3-Sep-03 18 0.0047 0.0142 0.0041 0.0058

19-Oct-04 20-Apr-05 4 0.0047 0.0142 0.0066 0.0138

22-Jun-05 15-Feb-06 5 0.0047 ND ND 0.0138 San Joaquin Site 1 26-Apr-06 27-Sep-07 25 0.0110 ND ND 0.0220

Site 1 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

Site 2 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

Site 3 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

Site 4 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

Site 5 10-Jan-95 10-Jan-95 1 0.01 ND ND ND

Site 6 10-Jan-95 10-Jan-95 1 0.01 ND ND ND

10-Jan-95 10-Jan-95 4 0.01 ND ND ND

9-Oct-01 20-Apr-05 20 0.0047 0.0142 0.0041 0.0058

22-Jun-05 15-Feb-06 5 0.0047 ND ND 0.0138

Site 7 26-Apr-06 9-Aug-06 3 0.0110 ND ND 0.0220

Site 8 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND

Stanislaus Site 9 10-Jan-95 10-Jan-95 1 0.0100 ND ND ND



### In conclusion, surface water monitoring data are summarized in the following Table
3.16

.

Table 3.16 Surface water data summary

Cnty= No of counties; Site= No of Sites; Smpl= No of Samples

Data Source CDPR1991-1996 CDPR 2001-2006 STORET 2001-2008 NAQWA (1995 & 2001-2007) Total Number of: Cnty Site Smpl Cnty Site Smpl Cnty Site Smpl Cnty Site Smpl

Endosulfan Species 9 83 2,000 24 153 500 21 100 304 5 15 200

α (Max ppb) 0.22 Not Determined 0.008 <0.011 β (Max ppb) 0.17 Not Determined 0.0064 <0.0142 Sulfate (Max ppb) 0.56 0.005 ppb 0.005 <0.022



### 90

### 3.2.4.2 Groundwater Monitoring Data No ground water monitoring data were re ported for California by the CDPR for endosulfan isomers and the common degradate. However, ground water monitoring data were reported by NAWQA for 11 California c ounties from 149 ground water wells. Data
showed no detections of α - , β - and ether- endosulfan, and/or endosulfan sulfate.
Detection limits varied for the vari ous endosulfan species: 0.0047 to 0.011 ppb for α endosulfan, 0.0142 ppb for β - endosulfan, 0.0041 ppb for ether- endosulfan and 0.0058 to 0.022 ppb for endosulfan sulfate ( Table 3.17 ). Both β - endosulfan and ether- endosulfan
were not determined for n early 39% of the samples.

Table 3.17 A summary of monitoring data for ground water from California

Well Depths (ft) Endosulfan Species Detection Limits (ppb)

County Number of
Wells Min Max Alpha Beta Ether SO4 Sampling Dates

7 114 300 0.011 ND ND 0.022 Jun-06; Aug-06

Fresno 26 68 390 0.0047 0.0142 0.0041 0.0058 Jul-01; Aug-01; Sep-01; Jun-02

Kern 1 300 300 0.011 ND ND 0.022 Aug-06 Kings 3 55 244 0.0047 0.0142 0.0041 0.0058 Jul-02

Madera 6 165 265 0.0047 0.0142 0.0041 0.0058 Sep-01; Jul-02

5 96 230 0.011 ND ND 0.022 Jun-06; Aug-06

Merced 13 56 265 0.0047 0.0142 0.0041 0.0058 Oct-01; Jul-02; Aug-02 Orange 2 942 1,020 0.011 ND ND 0.022 Jun-06

Sacramento 31 37 200 0.0047 ND ND 0.0138 Jul-05; Aug-05; Sep-05; Aug-06

San Bernardino 5 234 900 0.011 ND ND 0.022 Jun-06; Aug-06

1 175 175 0.011 ND ND 0.022 Aug-06 San Joaquin 14 44 250 0.0047 0.0142 0.0041 0.0058 Sep-01; Oct-01; Sep-02

3 110 195 0.011 ND ND 0.022 Jun-06; Aug-06

Stanislaus 18 33 195 0.0047 0.0142 0.0041 0.0058 Oct-01; Nov-01; Jun-02; Aug-02

3 182 310 0.011 ND ND 0.022 Jun-06; Aug-06

Tulare 10 118 313 0.0047 0.0142 0.0041 0.0058 Sep-01; Jun-02; Aug-02

* ND= Chemical species was not determined



### In conclusion, ground water monitori ng data are summarized as follows:

• No CDPR data; and

• NAQWA (2001-2006): 11 counties; 149 we lls: Alpha <0.011 ppb; Beta<0.0142 ppb; and Sulfate <0.022 ppb

3.2.4.3 Sediment Monitoring Data

Bottom sediment monitoring data were repo rted by NAWQA for 18 California counties
from 49 surface water sites. No detections were observed in the 53 samples which were analyzed for α -endosulfan only. Reported values were all less than the limit of detection of 0.2 to 2 μg/Kg of α -endosulfan ( Table 3.18 )

Table 3.18 A summary for NAWQA monitoring data to base sediment in California

Number of Concentration County Sampling Dates Sites Samples Alpha (μg/Kg) Stanislaus (Sept, 01) 1 1 0.2



### 91Number of Concentration County Sampling Dates Sites Samples Alpha (μg/Kg) Alpine (Sept, 92); Colusa (Oct, 95); El Dorado (Sept, 92); Fresno (Oct, 92); Kings (Oct, 92) and Orange (Sept, 98) 1 each 1 each Nevada (Sept, 92 & Oct, 96) 1 2 Shasta (Oct, 95) and Yuba (Nov, 95) 2 each 2 each San Joaquin (Oct, 92 & Nov, 97) 2 3 Riverside (Sept, 98); Sacramento (Oct & Nov, 95); Sutter (Nov & Oct, 95); Tehama (Oct, 95) and Yolo (Oct, 95) 3 each 3 each Merced (Oct, 92); 4 4 San Bernardino (Sept & Nov, 98) 6 6 Stanislaus (Oct, 92 & Nov, 97) 8 10 1

Riverside (Sept, 98); and San Bernardino Sept, 98 1 each 1 each 2



### In STORET 22 

### , data are reported on monitored sediment (2 meter deep) from September, 2001 to January, 2003 for α - and β -endosulfan and/or endosulfan sulfate in eleven counties in California. Reported data show a single detection (one sample out of 84 samples) with a concentration of 9.01ng/g for α - and β -endosulfan ( Table 3.19 ).
Examination of the surface water data associ ated with this sediment sample shows no detection of any endosulfan species

Table 3.19 Summary of bottom sedi ment monitoring da ta for California

County Monitoring Year(s) No of Sites No of Samples*

Alameda September, 2001 2 4

Contra Costa September, 2001 & June, 2002 2 3 Imperial May, September & October, 2002 20 46 Los Angeles January, 2003 1 1

Marin October, 2001 & June 2002 3 4
Riverside May, September & October, 2002 6 13
San Bernardino May & October, 2002 2 4

San Mateo June, 2002 2 3
Santa Clara June, 2002 2 3
Solano June, 2002 1 1

Ventura November, 2001 1 2

Overall September, 2001 to January, 2003 42 84

* Number of samples may not match the number of sites because of sampling the same site at different dates



### In conclusion, sediment data are summarized as follows:

• No CDPR data;

• NAQWA (1992-1998): 18 counties, 49 sites, and 58 samples: Alpha <2 ppb; Others Not determined; and

• STORET (2002-2003) 11 Counties; 42 sites, an d 84 samples: Only single sample with 9.01 ng/g concentration for alpha endosulfan

3.2.4.4 Atmospheric Monitoring Data

22 STORET Data base URL: http://www.epa.gov/storet/dw_home.html



### 92

### α -, β -endosulfan and endosulfan sulfate may be c onsidered as semi-volatile chemicals. Vapor pressures for the three chemicals are 4.56x10 -5 

### torr for α -endosulfan, 2.40x10 -5 

### torr for β -endosulfan, and 9.75x10 -6 

### torr for endosulfan sulfate. Vapor pressure values suggest that the three chemicals may volatilize into the air from dry soil/plant surfaces. Calculated Henry’s Law constants are 3.03x10 -6 

### atm m 3 

### mol -1 

### for α -endosulfan, 1.38x10 -6



### atm m 3 

### mol -1 

### for β -endosulfan, and 1.64x10 -5 

### atm m 3 

### mol -1 

### for endosulfan sulfate. Values indicate that the three chemicals may also vol atilize from water or wet soils. The three endosulfan chemical species appear to have th e ability to partition in to air in relatively important amounts and persist long enough to be transported by air into distant areas. Reported half lives in th e air were 2.7 days for α -endosulfan and 15 days for β

endosulfan (Schenker et al. 2005), and 2.6 days for endosulfan sulfate as estimated by EpiSuit V 4.0 23 

### . Chemicals with half-life of ≥ 2 days in the air can be considered to be persistent in this media (SAP, 2009) 24



### .

Based on physiochemical and fate properties, endosulfan may move from the application site to edge and near-field by drift and can be carried away by short and long-range transport. Air monitoring and modeling may be used to evaluate the importance of these two dissipation routes for exposure to edge/n ear field and nearby and far away areas.

Drift Monitoring (Edge & Near-field)

A 24-hour drift monitoring study (referred to in the study description as application site monitoring) was conducted duri ng the month of April in San Joaquin County (CDPR, 1998) 25 

### . The study included four air sampling st ations placed on nor th, south, east, and west sides of an 8.5 acre apple orchard fiel d (at 54, 27, 21 and 33 ft from field edge, respectively). Endosulfan was applied by ground equipment at a rate of 1.5 lbs a.i. /A to represent application to apples and cherries (current rate can be up to 2.5 lbs a.i. /A). At each site, samples were collected at seven intervals: 1.00, 1.90, 4.00, 8.10, 9.50, 23.75, and 24.00 hours following application.

A total of 28 sample events were collected within the 24-hour period at the four field locations. This study represents a specif ic pesticide application followed by drift monitoring at specific times/locations for endos ulfan leaving the application field. Data show relatively high detects/concentrati ons for alpha endosulfan compared to low
detect/concentrations for beta endosulfa n and no detects for endosulfan sulfate (
Table 3.20 ).

23 The Estimation Program s Interface EPI Suite: http://www.epa.gov/oppt/exposure/pubs/episuitedl.htm

24 SAP (The FIFRA Scientific Adviso ry Panel). 2009. Minutes for the SAP Meeting on selected issues associated with risk assessment process for pes ticides with persistent, bio-accumulative and toxic characteristics. October 28-31, 2008. Arlington, VA. (Document No. 2009-01 dated Jan 29, 2009).

25 CDPR, 1998 Report for the Air Monitoring of Endosulfan in Fresno County (Ambient) and in San Joaquin County (Application) , Air Resources Board, California Environmental Protection Agency, Monitoring and Laboratory Division, Engineering and Laboratory Branch, Project No. C96-034 Dated April 17, 1998



### 93

### Table 3.20 Frequency and concentrations of endosulfan species in ambient air

% of Total Samples in various Detection Categories *

Endosulfan Species “No Detect” Low Concentration
Detects High concentration

Detects Totals

Alpha 4% 4% 92% 100%

Beta 36% 14% 50% 100%
Sulfate 100% 0% 0% 100%

* Detection Categories (no categories specified for endosulfan sulfate “SO 4 ”): “None”: <3.1 ng/m 3 for alpha, and <6.2 ng/m 3 for beta
“Low Detects” : 3.1 to ≤ 10 ng/m 3 for alpha, and 6.2 to ≤ 20 ng/m 3 for beta “High Detects”: >10 ng/m 3 for alpha; > ng/m 3 for beta. These detects ranged from 4.1-140 ng/m 3 for alpha endosulfan and were only three detects at 13, 13 and 26 ng/ m 3 for beta endosulfan

Detection/Quantification limits (LOD= Limit of detection; LOQ= Limit of quantification Assuming 0.96 m 3 samples (8 hours sampling period @ 2 Liters/Min): Alpha: LOD=3.1 ng/m 3 and LOQ= 10 ng/ m 3 ; Beta: LOD= 6.2 and LOQ= 20 ng/ m 3 , and LOQ= 19.6 ng/ m 3 for SO 4 (endosulfan sulfate)



### Figure 3.8 summarizes monitori ng data reported for α - and β - endosulfan (endosulfan
sulfate was not detected over the detection limit).

0 100 200 300 400 500 600 700Monitered Concentration (ng/m3)

Alpha (East) Beta (East) Alpha (North) Beta (North) Alpha (South) Beta (South) Alpha (West) Beta (West)

Monitered Endosulfan Species and direction of the station location from field

Note 1: 4 out of scale concentrations are 1,800; 3,800; 1,200 & 1,200 ng/m3 from left to right, respectively Figure 3.8 Concentration profiles for α - and β - endosulfan at the edge and near-field in ambient air following application in Sa n Joaquin County, California



### Additionally, data suggest th at applied 70:30 mixture of α - and β - endosulfan drifted from the application site in disproportional quantities in the four main directions. Endosulfan sulfate was not found above the LOQ in any of the application samples. On the average, the ratio between α - and β - endosulfan in drifted mate rial was in the range of 7-23:1 compared to nearly 2:1 in the a pplied formulation. High concentration of α endosulfan (up to 2x β - endosulfan) may be explained by the disproportional quantities in the applied parent. However, observed enrichment of drifted material with α - endosulfan, up to 23x β - endosulfan, could not be fully expl ained. Higher vapor pressure of α compared to β - endosulfan may have contribut ed to observed result.

94

### Results indicate that concentrations of α - and β - endosulfan were highest in drift moving through the east edge of the field followed by the north, then the south with lowest concentrations moving to the west. Additiona lly, peak concentrations in the drift were generally observed within th e first four hours after application. The relative drift distribution was partially rela ted to wind speed and directio n. Wind rose data throughout the first five periods were from the west a nd north-west and the sout h west at the end of these periods. Wind directio ns during the last two periods were from the west, north,
north-west with addi tional wind from the north-east at th e start of the last period. Other factors may have also contri buted to observed results such as application direction (application started at the north -west corner of the plot with the rows oriented east/west), average width of area downwind, distance of sampling station from field edge. Other factors may have also contri buted to observed variations including temperature, relative humidity and sun light. Changes in thes e parameters are expected because the experiment started early in the morning of 4/8/97 at 5:30 AM and ended in the morning
of 4/10/97 at 8.00 AM.

Short-Range Transport Monitoring

Levels of twelve pesticides , including total endosulfan 26 

### , were determined in ambient air
collected at three residential locations within the vicinity of Salinas, California (CDPR, 1985) 27 

### . The study coincided with expected time of pesticid e applications but was not designed to coincide with any specific pesticid e application sites or times. At each site, a three day sampling period was used with four six hour sampling times starting from mid night, early morning (6:00 AM), noon, and night (6:00 PM). Endosulfan was detected in two out of the twelve air samples in a site located 1,200 ft from any agricultural field and in four out of 12 samples in another site locat ed at only 190 ft from any agricultural field.
All of the six detections were within a range of 37- 55 ng/m 3 

### (31- 46 ppt) 28 

### . Positive detections were in samples collected early in the day, coinciding with the time when pesticides were applied to nearby fiel ds, although wind speeds were lowest.

In another ambient air monitoring study, α - and β - endosulfan and endosulfan sulfate
were determined in ambient air collected every 24-hours at five sampling sites in relatively high-population areas in Fresno County (CDPR, 1998) 29 

### . A total of 125 samples were collected within five weeks at f our sites. Sites were in proximity to cotton and grape growing areas (two sites were with in 50-100 yards and two were within 0.75-2 miles). Sampling periods were during the months of July and August to coincide with the

26 Note: It was not clear from the study report whethe r concentrations were for total endosulfan but it appears that at least α - and β - endosulfan were monitored.

27 CDPR, 1985 Monterey County Residential Air Monitoring By R.J. Sava, et al, Environmental Hazards Assessment Program, Department of Pesticide Regulation, California Environmental Protection Agency, Sacramento, CA 9 5814-5624 dated December 1985 , Reprinted December 1995

28 pptt= ng/m 3 multiplied by 0.833

29 CDPR, 1998 Report for the Air Monitoring of Endosulfan in Fresno County (Ambient) and in San Joaquin County (Application) , Air Resources Board, California Environmental Protection Agency, Monitoring and Laboratory Division, Engineering and Laboratory Branch, Project No. C96-034 Dated April 17, 1998



### 95

### application of endosulfan on cotton and grapes . Again, no specific pesticide application
sites or times were associated with the study. Data show relatively high
detects/concentrations for al pha endosulfan compared to low detect/concentrations for beta endosulfan and no detects for endosulfan sulfate ( Table 3.21 ).

Table 3.21 Frequency and concentrations of endosulfan species in ambient air

% of Total Samples in various Detection Categories *

Endosulfan Species “None” Low Concentration
Detects High Concentration

Detects Totals

Alpha 18% 9% 73% 100%

Beta 68% 29% 3% 100%
Sulfate 100% 0% 0% 100%

* Detection Categories (no categories specified for endosulfan sulfate “SO 4 ”): “None”: <0.58 ng/m 3 for alpha, and <1.91 ng/m 3 for beta
“Low Detects” : 0.58 to ≤ 2.49 ng/m 3 for alpha, and 1.91 to ≤ 8.16 ng/m 3 for beta “High Detects”: >2.49 ng/m 3 for alpha; >8.16 ng/m 3 for beta. These detects ranged from 4.1-140 ng/m 3 for alpha endosulfan and were only three detects at 13, 13 and 26 ng/ m 3 for beta endosulfan

Detection/Quantification limits (LOD= Limit of detection; LOQ= Limit of quantification Assuming 2.88 m 3 samples (24 hours sampling period @ 2 Liters/Min): Alpha: LOD=1.1 ng/m 3 and LOQ= 3.8 ng/ m 3 ; Beta: LOD= 3.8 and LOQ= 12 ng/ m 3 ; and LOQ= 12.8 ng/ m 3 for SO 4 (endosulfan sulfate)



### Data suggest that application of endo sulfan may have caused partitioning of α - and β

endosulfan into ambient air to suppor t maximum concentrations of 140 ng/m 3 

### for α endosulfan (the 70% isomer in the formulation) and 26 ng/m 3 

### for β - endosulfan (the 30% isomer in the formulation). The same conc lusion applies for dete ction frequencies of low/high concentrations. These frequencies were 82% for α - endosulfan and 31% for β

endosulfan (refer to Table 3.21 : 82%= 9%+73%; and 31%= 29%+3%). Figure 3.9 summarizes data for the main species detected, α - endosulfan.

96Figure 3.9 Concentration profiles for α - endosulfan in ambient air during a period of five weeks at 4 sites in Fresno County, California.

0 10 20 30 40 50Monitered Concentration (ng/m3)

Site 1 Site 2 Site 3 Site 4

Time: From zero to 5 weeks for each site

Note 1: Distance from Cotton fields: sites 1&2 = 150-300 ft.; Site 3= 0.75-1.0 mile; Site 4= 1-2 miles.
Note 2: The 4 out of scale concentrations are 130, 120, 140, and 70 ng/m3 from left to right, respectively



### Based on data shown in Figure 3.9

, α - endosulfan appears to be present in the ambient air of near field areas where its parent is applied to cotton and grapes. Although relatively high spikes of concentrations exist, concentration levels of the chemical appear to be mainly in the range of 5 to 35 ng/m 3 

### (4- 29 ppt) which is lower than concentrations monitored in 1985 (37- 55 ng/m 3 

### = 31- 46 ppt). These near fi eld areas were in the range of 50 yards to 2 miles from possible applic ation sites suggesting that endosulfan had partitioned into the air and moved within short-range distances. Dissipation of endosulfan into and within the air mass is prob ably related to a combination of drift and
volatilization.

Long-Range Transport Monitoring

Atmospheric transport from CA central valley and re-deposition in the Sierra Nevada
Mountains were documented for α - and β - endosulfan and endosulfan sulfate. As a result of atmospheric transport, th e three chemicals have been found in the mountainous regions
of California in air surfa ce water, sediment, precipita tion/snow-pack, and biota.

Endosulfans were detected in air sample s taken from Sequoia and King Canyon National Parks (Landers et al. 2008) in average c oncentrations of approximately 1,250 pg/g dry
XAD. Levels of endosulfan detected in the Ca lifornia National Park s were greater than those measured in any other park in the study (Sequoia/Kings Canyon, Rocky Mountain, Mount Rainier, Glacier, Denali, No atak, and Gates of the Arctic).

In surface water, residues of α -, β -endosulfan and endosulfan sulfate were present in water from both Tablelands and Sixty Lake s in the Sierra Nevada Mountains of California (Fellers et al . 2004). Similar concentrati ons were detected for α - and β

endosulfan from the Tablelands and Sixt y Lakes sampling areas, however endosulfan
sulfate concentrations in Tabl elands were almost an order of magnitude higher than in

97

### Sixty Lakes and almost four times greater than β - endosulfan concentrations from the same locations ( Table 3.22 ). The α -isomer was also detected at two locations and at various depths in Lake Tahoe in concentr ations ranging from < 0.004 to 0.26 ng/L which
are similar to that found in snow in the surrounding basin (McConnell et al. 1998).
Endosulfan was one of the most common curre nt use pesticide detected in sediment collected from lakes in Sequoia and Kings Canyon National Parks with an average flux of approximately 130 ng/m 2 

### /y

Table 3.22 

### Concentration of pesticides (ng/L) in surface water samples collected at the Tablelands (Sequoia National Park), and th e Sixty Lake Basin (Kings Canyon National Park) California, USA (Fellers et al. 2004).

Tablelands Sixty Lakes

Chemical Compound
Detection limit G049 G054 S545 S471



### α -endosulfan 0.03 0.78 1.0 0.30 0.37 β -endosulfan 0.05 0.40 0.42 1.8 0.17

Endosulfan sulfate 0.03 2.9 2.2 0.33 0.40

In precipitation/snow pack, endosulfan and endosulfan sulfate were detected in seasonal snow pack samples at seven national park s in the Western United States, including mountainous regions in California (Sequoia, Rocky Mountain, Mount Rainier, Glacier, Denali, Noatak, and Gates of the Arctic ; Hageman et al. 2006). In this study,
concentrations of total endosulfan measured in seasonal snow pack ranged from < 0.0040 to 1.5 ng/L and the percent contribution of endosulfan sulfate to the total endosulfan concentration averaged 24.0%. McConnell et al. (1998) reported e ndosulfan was present in snow and rain samples from two elevatio ns in Sequoia National Park and the southern Sierras, a region adjacent to California’s Central Valley which is among the heaviest pesticide use areas in the U.S. Levels of α -endosulfan found in precip itation range from < 0.035 to 6.5 ng/L while β -endosulfan ranged from < 0.012 to 1.4 ng/L (McConnell et al. 1998).

Endosulfan was also found in mountain yellow-legged frogs ( Rana muscosa ) from two
areas in the Sierra Nevada Mountains in California (Sixty Lakes Basin, Kings Canyon National Park and Tablelands, Sequoia national Park; Fellers et al. 2004). Of the two endosulfan isomers and the sulfate degradate, only the α -isomer was observed at levels above quantitation. Co ncentrations of α -endosulfan averaged 0.56 (± 0.36) and 0.45 (± 0.24) ng/g wet weight at Ta blelands and Sixty Lakes Basin, respectively. These Concentrations were not significantly differentfrom the two sites (F ellers et al 2004).
Endosulfan sulfate was measured in fish from Sequoia and Kings Canyon National Parks at average concentrations of approximately 30 ng/g lipid, which was one of the highest concentrations reported in fish throughout the western parks (Landers et al. 2008).

Total Endosulfan (sum of α , β , and sulfate) was measured in lichen and conifer samples in Sequoia and Kings Canyon National Parks at average concentrations of 488 and 192 ng/g, respectively (Landers et al. 2008). In this study endosulfans, along with dacthal, dominated the total pesticide laoding in vegetation samples from the lower 48 states.

98

### 3.3 Terrestrial Animal Exposure Assessment

A primary concern of endosulfan application is that birds and mammals may be exposed through oral or dietary exposure to vegetative plant material or insects when foraging in treated fields for nesting mate rial or food. Estimation of e ndosulfan concentrations in wildlife food items focuses on quantifying po ssible dietary ingestion of residues on vegetative matter and insects. The EFED terrestrial exposure model T-REX (T-REX, Version 1.4.1, dated October 9, 2008) simulates a one-year time period and is used to estimate exposures and risks to avian (surro gate for terrestrial-phase amphibians and reptiles) and mammalian species. Avian and mammalian toxicity, chemical application, and foliar dissipation half-life data are input for the model, which provides estimates of exposure concentrations (EECs) and risk quotients (RQs). Sp ecifically, the model provides estimates of concentrations (upper- bound and mean) of chemical residues on the surface of different types of foliage and insect s that may be dietary sources of exposure to avian, mammalian, reptilian, or terrestrial-pha se amphibian receptors. The surface residue concentration (ppm) is estimated by multiply ing the application rate (pounds active ingredient per acre) by a value specific to each food item (termed the Hoerger-Kenaga estimates). For multiple applications, the EEC is determined by adding the mass on the surface immediately following th e application to the mass of the chemical still present on the surfaces on the day of application (deter mined based on first order kinetics using the foliar half-life as the rate constant). The Ho erger-Kenaga estimates and a more detailed discussion of the methodology implemented by T-REX can be found at http://www.epa.gov/oppefed1/models/terrestrial/

.

T-REX is also used to calculate EECs for terrestrial insects expos ed to endosulfan via spray applications. Dietary-based EECs calculated by T-REX for small (broadleaf plants/small insects dietary category) and la rge (fruits/pods/seeds/large insects dietary category) invertebrates (units of a.i./g) are used to bound an estimate of exposure to
terrestrial invertebrates. Availa ble acute contact toxicity data for bees (or other terrestrial invertebrates) exposed to endos ulfan (in units of μg a.i./org anism), are converted to μg a.i./g (of organism) by dividing by the body weight of an individual organism used in the test. For honey bees, the body weight of a bee is assumed to be 0.128 g. The EECs are later compared to the adjusted acute contact toxicity data for terrestrial invertebrates in order to derive RQs for terrestrial invertebrates.

Terrestrial EECs were derived for use categor ies (apples, cotton, grapes, lettuce, pecans, potatoes, tobacco, and tomatoes) using current application rates and intervals between applications. Uncertainties in the terrestrial EECs are primarily associ ated with a lack of data on interception and subsequent dissipati on from foliar surfaces. Use-specific input values, including number of applications, appli cation rate, foliar hal f-life and application interval are provided in Table 3.23 . The maximum number of applications per year, the minimum application intervals, and the maximu m application rates for each crop selected as the representative crop for a “Crop Cate gory” were derived from the product labels ( Table 2.3 ) and Willis and McDowell (1987) summari zed seven studies which evaluated the foliar persistence of endos ulfan on a variety of crops. Fo liar half-lives ranged from 1

99

### to 5 days on a variety of crops (cotton, grapes, pears, tobacco , alfalfa, beets, and leafy vegetables) in studies conducted in Ca lifornia, Arizona, Kentucky, Canada, and Australia. The mean of the 13 reported half-l ife values was 3.2 days (standard deviation of 1.4 days). The upper 90th percent confidence interval value for the mean (4 days) was used as the foliar dissipation rate for modeling purposes.

The model was run for agricultural uses with the maximum single application rate and number of applications as proposed on the labels; however, it shoul d be noted that in some instances recommended label use may in clude either a single application of the maximum allowable seasonal rate or multiple applications of lower rates totaling the season maximum. The scenario which yielded the highest EEC and RQ values were used for each use category where multiple applic ation methods were possible. The upperbound Kenaga nomogram estimates reported by T-RE X have been used for derivation of the EECs for the terrestrial organisms and their potential prey ( Table 3.23 ). An example output from T-REX is available in Appendix F

.

Table 3.23 Summary of Do se and Dietary-based EECs Used for Esti mating Dietary Risks to Terrestrial Organisms using T-REX ver. 1.4.1.

Dose-Based EECs

Avian size class (grams) Mammalian size class (grams) Use Category App Rate (lb a.i./A, # Apps,
Interval

(da)) Dietary Category

20 100 1000 15 35 1000 Dietary EECs

Short Grass 546.67 311.74 139.57 457.64 316.29 73.33 480.00

Tall Grass 250.56 142.88 63.97 209.75 144.97 33.61 220.00

Broadleaf Plants/ Small Insects 307.50 175.35 78.51 257.42 177.91 41.25 270.00

Fruits/Pods/ Seeds/ Large Insects 34.17 19.48 8.72 28.60 19.77 4.58 30.00 Almonds,
hazelnut &
walnut 2, 1,

Granivore 7.59 4.33 1.94 6.36 4.39 1.02

Short Grass 683.34 389.67 174.46 572.05 395.37 91.67 600.00

Tall Grass 313.20 178.60 79.96 262.19 181.21 42.01 275.00

Broadleaf Plants/ Small Insects 384.38 219.19 98.13 321.78 222.39 51.56 337.50
Fruits/Pods/ Seeds/ Large Insects 42.71 24.35 10.90 35.75 24.71 5.73 37.50 Citrus 2.5, 1,

Granivore 9.49 5.41 2.42 7.95 5.49 1.27

Short Grass 354.60 202.21 90.53 296.85 205.16 47.57 311.35

Tall Grass 162.52 92.68 41.49 136.06 94.03 21.80 142.70

Broadleaf Plants/ Small Insects 199.46 113.74 50.92 166.98 115.40 26.76 175.14
Fruits/Pods/ Seeds/ Large Insects 22.16 12.64 5.66 18.55 12.82 2.97 19.46 Broccoli, cabbage, Chinese cabbage, cauliflower,
kohlrabi 1, 2, 7

Granivore 4.92 2.81 1.26 4.12 2.85 0.66

Short Grass 205.00 116.90 52.34 171.62 118.61 27.50 180.00

Tall Grass 93.96 53.58 23.99 78.66 54.36 12.60 82.50

Broadleaf Plants/ Small Insects 115.31 65.76 29.44 96.53 66.72 15.47 101.25
Fruits/Pods/ Seeds/ Large Insects 12.81 7.31 3.27 10.73 7.41 1.72 11.25 Kale, Collards &
Mustard Green 0.75, 1,

Granivore 2.85 1.62 0.73 2.38 1.65 0.38

Short Grass 410.00 233.80 104.68 343.23 237.22 55.00 360.00

Tall Grass 187.92 107.16 47.98 157.31 108.73 25.21 165.00

Broadleaf Plants/ Small Insects 230.63 131.51 58.88 193.07 133.44 30.94 202.50 Sweet corn 1.5, 1,

Fruits/Pods/ Seeds/ Large Insects 25.63 14.61 6.54 21.45 14.83 3.44 22.50



### 100Table 3.23 Summary of Do se and Dietary-based EECs Used for Esti mating Dietary Risks to Terrestrial Organisms using T-REX ver. 1.4.1.

Dose-Based EECs

Avian size class (grams) Mammalian size class (grams) App

Use Category Rate (lb a.i./A, # Apps,
Interval

(da)) Dietary Category

20 100 1000 15 35 Dietary EECs

1000

Granivore 5.69 3.25 1.45 4.77 3.29 0.76

Short Grass 273.34 155.87 69.78 228.82 158.15 36.67 240.00

Tall Grass 125.28 71.44 31.98 104.88 72.48 16.81 110.00

Broadleaf Plants/ Small Insects 153.75 87.68 39.25 128.71 88.96 20.63 135.00
Fruits/Pods/ Seeds/ Large Insects 17.08 9.74 4.36 14.30 9.88 2.29 15.00 Cotton (ground) 1, 2,

Granivore 3.80 2.16 0.97 3.18 2.20 0.51

Short Grass 265.95 151.66 67.90 222.64 153.87 35.68 233.51

Tall Grass 121.89 69.51 31.12 102.04 70.52 16.35 107.03

Broadleaf Plants/ Small Insects 149.60 85.31 38.19 125.23 86.55 20.07 131.35
Fruits/Pods/ Seeds/ Large Insects 16.62 9.48 4.24 13.91 9.62 2.23 14.59 Cotton (Areal) 0.75, 2, 7

Granivore 3.69 2.11 0.94 3.09 2.14 0.50

Short Grass 683.34 389.67 174.46 572.05 395.37 91.67 600.00

Tall Grass 313.20 178.60 79.96 262.19 181.21 42.01 275.00

Broadleaf Plants/ Small Insects 384.38 219.19 98.13 321.78 222.39 51.56 337.50
Fruits/Pods/ Seeds/ Large Insects 42.71 24.35 10.90 35.75 24.71 5.73 37.50 Apples 2.5, 1,

Granivore 9.49 5.41 2.42 7.95 5.49 1.27

Short Grass 683.34 389.67 174.46 572.05 395.37 91.67 600.00

Tall Grass 313.20 178.60 79.96 262.19 181.21 42.01 275.00

Broadleaf Plants/ Small Insects 384.38 219.19 98.13 321.78 222.39 51.56 337.50
Fruits/Pods/ Seeds/ Large Insects 42.71 24.35 10.90 35.75 24.71 5.73 37.50 Apricot, nectarine, peach, cherry, pear, plum &

prune 2.5, 1,

Granivore 9.49 5.41 2.42 7.95 5.49 1.27

Short Grass 388.26 221.40 99.12 325.03 224.64 52.08 340.91

Tall Grass 177.95 101.48 45.43 148.97 102.96 23.87 156.25

Broadleaf Plants/ Small Insects 218.40 124.54 55.76 182.83 126.36 29.30 191.76
Fruits/Pods/ Seeds/ Large Insects 24.27 13.84 6.20 20.31 14.04 3.26 21.31 Lettuce &
Brussels sprouts 1, 2, 5

Granivore 5.39 3.08 1.38 4.51 3.12 0.72

Short Grass 354.60 202.21 90.53 296.85 205.16 47.57 311.35

Tall Grass 162.52 92.68 41.49 136.06 94.03 21.80 142.70

Broadleaf Plants/ Small Insects 199.46 113.74 50.92 166.98 115.40 26.76 175.14
Fruits/Pods/ Seeds/ Large Insects 22.16 12.64 5.66 18.55 12.82 2.97 19.46 Cucumber, melons, pumpkin & squash 1, 2, 7

Granivore 4.92 2.81 1.26 4.12 2.85 0.66

Short Grass 136.67 77.93 34.89 114.41 79.07 18.33 120.00

Tall Grass 62.64 35.72 15.99 52.44 36.24 8.40 55.00

Broadleaf Plants/ Small Insects 76.88 43.84 19.63 64.36 44.48 10.31 67.50
Fruits/Pods/ Seeds/ Large Insects 8.54 4.87 2.18 7.15 4.94 1.15 7.50 Eggplant 0.5, 1,

Granivore 1.90 1.08 0.48 1.59 1.10 0.25

Short Grass 166.01 94.67 42.38 138.97 96.05 22.27 145.76

Tall Grass 76.09 43.39 19.43 63.70 44.02 10.21 66.81

Broadleaf Plants/ Small Insects 93.38 53.25 23.84 78.17 54.03 12.53 81.99
Fruits/Pods/ Seeds/ Large Insects 10.38 5.92 2.65 8.69 6.00 1.39 9.11 Ornamentals
& shade

trees 0.5, 6, 10

Granivore 2.31 1.31 0.59 1.93 1.33 0.31



### 101Table 3.23 Summary of Do se and Dietary-based EECs Used for Esti mating Dietary Risks to Terrestrial Organisms using T-REX ver. 1.4.1.

Dose-Based EECs

Avian size class (grams) Mammalian size class (grams) App

Use Category Rate (lb a.i./A, # Apps,
Interval

(da)) Dietary Category

20 100 1000 15 35 Dietary EECs

1000

Short Grass 388.26 221.40 99.12 325.03 224.64 52.08 340.91

Tall Grass 177.95 101.48 45.43 148.97 102.96 23.87 156.25

Broadleaf Plants/ Small Insects 218.40 124.54 55.76 182.83 126.36 29.30 191.76
Fruits/Pods/ Seeds/ Large Insects 24.27 13.84 6.20 20.31 14.04 3.26 21.31 Potato 1, 2, 5

Granivore 5.39 3.08 1.38 4.51 3.12 0.72

Short Grass 218.29 124.48 55.73 182.74 126.30 29.28 191.67

Tall Grass 100.05 57.05 25.54 83.76 57.89 13.42 87.85

Broadleaf Plants/ Small Insects 122.79 70.02 31.35 102.79 71.04 16.47 107.81
Fruits/Pods/ Seeds/ Large Insects 13.64 7.78 3.48 11.42 7.89 1.83 11.98 Sweet potato 0.5, 3, 5

Granivore 3.03 1.73 0.77 2.54 1.75 0.41

Short Grass 388.26 221.40 99.12 325.03 224.64 52.08 340.91

Tall Grass 177.95 101.48 45.43 148.97 102.96 23.87 156.25

Broadleaf Plants/ Small Insects 218.40 124.54 55.76 182.83 126.36 29.30 191.76
Fruits/Pods/ Seeds/ Large Insects 24.27 13.84 6.20 20.31 14.04 3.26 21.31 Dry beans (except Lima), peas & pepper 1, 2, 5

Granivore 5.39 3.08 1.38 4.51 3.12 0.72

Short Grass 273.34 155.87 69.78 228.82 158.15 36.67 240.00

Tall Grass 125.28 71.44 31.98 104.88 72.48 16.81 110.00

Broadleaf Plants/ Small Insects 153.75 87.68 39.25 128.71 88.96 20.63 135.00
Fruits/Pods/ Seeds/ Large Insects 17.08 9.74 4.36 14.30 9.88 2.29 15.00 Carrot 1, 1,

Granivore 3.80 2.16 0.97 3.18 2.20 0.51

Short Grass 273.34 155.87 69.78 228.82 158.15 36.67 240.00

Tall Grass 125.28 71.44 31.98 104.88 72.48 16.81 110.00

Broadleaf Plants/ Small Insects 153.75 87.68 39.25 128.71 88.96 20.63 135.00
Fruits/Pods/ Seeds/ Large Insects 17.08 9.74 4.36 14.30 9.88 2.29 15.00 Celery 1, 1,

Granivore 3.80 2.16 0.97 3.18 2.20 0.51

Short Grass 293.65 167.45 74.97 245.83 169.90 39.39 257.84

Tall Grass 134.59 76.75 34.36 112.67 77.87 18.05 118.18

Broadleaf Plants/ Small Insects 165.18 94.19 42.17 138.28 95.57 22.16 145.03
Fruits/Pods/ Seeds/ Large Insects 18.35 10.47 4.69 15.36 10.62 2.46 16.11 Strawberry 1, 2, 15

Granivore 4.08 2.33 1.04 3.41 2.36 0.55

Short Grass 354.60 202.21 90.53 296.85 205.16 47.57 311.35

Tall Grass 162.52 92.68 41.49 136.06 94.03 21.80 142.70

Broadleaf Plants/ Small Insects 199.46 113.74 50.92 166.98 115.40 26.76 175.14
Fruits/Pods/ Seeds/ Large Insects 22.16 12.64 5.66 18.55 12.82 2.97 19.46 Tomato 1, 2, 7

Granivore 4.92 2.81 1.26 4.12 2.85 0.66 N/A = Non-applicable



### Upper-bound Kenega nomogram values reporte d by T-REX are used for derivation of dietary EECs for evaluating direct and/or indire ct effects to terrestrial phase CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB. Potent ial direct acute and chronic effects of endosulfan to the terrestrial-phase CRLF, SFGS and CTS are derived by considering

102

### dietary-based exposures mode led in T-REX for a small bird (20g) consuming small
invertebrates.

Potential direct acute and chronic effects specifically to the SMHM are derived by considering dose- and dietar y-based EECs modeled in T-REX for a small mammal (15 g) consuming a variety of dietary items ( Table 3.23 ). Potential direct acute and chronic effects specifically to the SJKF are derived by considering dose- a nd dietary-based EECs modeled in T-REX for a large mammal (1,000 g) consuming a variety of dietary items ( Table 3.23 ).

3.4 Terrestrial Plant Exposure Assessment

No terrestrial plant toxicity data were av ailable for endosulfan that were considered acceptable for quantitative use in risk estimation. Therefore, risks to terrestrial plants could not be quantitatively assessed in this risk assessment but instead were qualitatively
considered.

103

# 4 Effects Assessment

This assessment evaluates the potential for endosulfan (and its primary degradate of concern, endosulfan sulfate) to directly or indirectly affect the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB or modify th eir designated critical habitat. As previously discussed in Section 2.7 , assessment endpoints for th e effects determination for each assessed species include direct to xic effects on the survival, reproduction, and growth, as well as indirect effects, such as reduction of the prey ba se or modification of its habitat. In addition, potential modificati on 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 each assessed species. Direct effects to the aquatic-phase CRLF and CTS are based on toxicity informati on for freshwater fish, while terrestrialphase CRLF, CTS and SFGS effects are based on avian toxicity data, given that birds are generally used as a surrogate for terrestria l-phase amphibians and reptiles when suitable data for terrestrial-phase amphi bians are not available.

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 freshwater fish (used as a surrogate for aquatic-phase amphibians), freshwater invertebrates, estuarine/marine fish, estuarin e/marine invertebrates, aquatic plants (nonvascular only; no data were available for vascular aquatic plants), birds (used as a surrogate for terrestrial-phase amphibians and reptiles), mammals, terrestrial invertebrates, and terrestrial plants (plants ar e only qualitatively eval uated due to lack of appropriate data). Acute (short-term) and ch ronic (long-term) toxicity information is characterized based on registrant-submitted studies and a comprehensive review of the open literature on endosulfan

Toxicity endpoints are esta blished based on data gene rated 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; http://www.epa.gov/med/Prods_Pubs/ecotox.htm). Open literature data presented in this assessment were obtained from ECOTOX information obtained on November 5, 2008. 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 ev aluated 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 mo re conservative (i.e.,

104

### show a lower toxicity endpoint) than the regi strant-submitted data are evaluated further. The degree to which open literature data are quantitatively or qualit atively characterized for the effects determination is dependent on whether the information is relevant to the assessment endpoints ( i.e. , survival, reproduction, a nd growth) identified in Section 2.8

. For example, endpoints such as biochemical m odifications are likely to be qualitatively evaluated, because quantitative relationships between biochemical modifications in the laboratory and reduction in species survival, reproduction, and/or grow th in the field are generally not available. A lthough this effects determination relies on endpoints that are relevant to the assessment endpoints of surviv al, growth, or reproduc tion, it is important
to note that the full suite of sublethal e ndpoints potentially ava ilable in the effects literature (regardless of their significance to the assessment endpoints) are considered to
define the action area for endosulfan.

The sublethal endpoint used to define the Action Area was based on reduction in growth for the sheepshead minnow (Hansen and Cr ipe, 1991; ECOTOX reference # 14143), who reported a LOAEC of < 0.27 ug a.i./L resu lting from 28-d, flow through exposures.

Citations of all open literature not evaluated 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 t hose studies that did not pass the ECOTOX screen and those that were not evaluated as part of th is endangered species risk assessment.

A detailed spreadsheet of the available ECOT OX open literature data, including the full
suite of lethal and subletha l endpoints is presented in Appendix H

. Appendix J contains a review of all the toxicity da ta considered in this assessment for aquatic species, while Appendix K contains the same informati on for terrestrial species. Appendix M also includes a summary of the human he alth effects data for endosulfan

. Because the stability of endosulfan TGAI in aquatic tests is a c oncern due to its volatility, preference was given to those studies that quantified endos ulfan exposure via anal ytical measurements and where appropriate, used a flow-through e xposure regime. In some cases, however, these data were lacking (e.g., aquatic nonvascul ar plants), and toxi city values based on nominal concentrations were used to fulfill a data gap. In general, studies from the open literature do not provide suffi cient documentation for evaluating all or most of the
OPPTS Guideline evaluation criteria. Consiste nt with the Overview Document (U.S.EPA 2004), if sufficient documentation was provided to judge that the open literature studies were scientifically valid and acceptable endpoi nts were determined that were below the ‘benchmark’ values, they were typically clas sified as supplemental--but acceptable for quantitative use. If sufficient documentation was not provided to comprehensively judge the scientific validity of the study but no information existed that suggested the study would be invalid, these studies were typically classified as supplemental--but acceptable for qualitative use. This classification was often applied to studies with nominal exposure
concentrations.

In addition to registrant-submitted and open lite rature toxicity information, other sources of information, including use of the acute pr obit dose response rela tionship to establish

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### the probability of an individual effect and re views of the Ecological Incident Information System (EIIS), are conducted to further refi ne the characterization of potential ecological effects associated with exposure to endosul fan. A summary of the available aquatic and terrestrial ecotoxicity inform ation, use of the probit dose response relationship, and the incident information for endosulfan are provided in Sections 4.1 through 4.4

, respectively.

As discussed in Section 2.4.1 , endosulfan sulfate is the primary degradate of toxicological concern for endosulfan ( α + β ). Available data suggest that the acute toxicity of endosulfan sulfate can be similar to the pa rent isomers, or on occasion, somewhat less toxic, depending on the species tested. For example, registrant-submitted studies of the
TGAI and endosulfan sulfate indicate similar acute toxicity to bluegill (1.7 vs. 3.8 ug/L, respectively; MRID 38806 and 46382604). Comp arison among two decapod crustaceans (grass shrimp and mysid shrimp) indicates the acute toxicity of parent isomers and the sulfate degrade are within the sa me order of magnitude (1.3 and 7.9 μ g/L, respectively; MRID 5005824 and 46406401). For avian species, registrant-submitted data indicate similar acute toxicity of endosulfan TGAI and endosulfan sulfate based on the avian acute oral study with bobwhite quail and subacute dietary studies with mallard and bobwhite quail (MRID 137189; 136998; 160000; 22923; 46382604). Comparative acute toxicity data available in the open literature for Daphnia magna

, Hyalella azteca and Oncorhynchus mykiss also support the finding of simila r acute toxicity of the sulfate degradate and parent TGAI; however, the exposur e regime used in these tests is uncertain
due to lack of confirmato ry analytical measurements (Wan et al., 2005; ECOTOX reference # 87973).

Acceptable studies comparing the chronic toxi city of the TGAI and sulfate degradate
were not identified in this re view. Therefore, consistent w ith the available data and the previous endosulfan risk assessment (U.S . EPA, 2007; D346213), the acute and chronic toxicity of endosulfan (TGAI) and endosulfan su lfate will be assumed to be equivalent. A detailed summary of the available ecotoxicity information for all endosulfan degradates and formulated products can be found in Appendices H

, J and K.

4.1 Toxicity of Endosulfan to Aquatic Organisms

Table 4.1 summarizes the most sensitive aquatic toxicity endpoints, 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, CT S. SFGS, SMHM, SJKF, BCB, and VELB is presented below. Additional information on species life histor y is provided in
Attachments 1 and 3.

106Table 4.1 Aquatic Toxicity Profile for Endosulfan (TGAI)

Assessment Endpoint Purity (% a.i.) Surrogate Species Toxicity Value Used for Quantitative
Risk Estimates ( μ g a.i./L) Effects Reference/Acceptability

Freshwater Fish and Aquatic-phase Amphibians (1)

Survival 96.2 Common Carp (Cyprinus carpio) LC50 = 0.1 Mortality Sunderam et al. 1992; ( ECOTOX 5850)/ Supplemental

Reproduction and Growth Not
Available Common Carp (Cyprinus carpio) NOAEC = 0.023 Not Available Estimated (2)

Freshwater Invertebrates

Survival 96 Mayfly (Atalophlebia australis) LC50 = 0.6 Mortality Leonard, et al. 1999 (ECOTOX 20012)/Supplemental

Reproduction and Growth Not
Available Mayfly (Atalophlebia australis)) NOAEC = 0.01 Not Available Estimated (3)

Sediment Toxicity (6) 99 Midge,

Chironomus tentans 20-d NOAEC = 0.35 Mortality and Emergence 47318101 /Acceptable

Estuarine/Marine Fish

Survival 96 Spot (Leiostomus xanthurus) LC50 = 0.09 Mortality MRID 5005824/Acceptable

Reproduction and Growth Not
Available Spot (Leiostomus xanthurus) NOAEC = 0.045 Not Available Estimated (4)

Estuarine/Marine Invertebrates

Survival 96 Pink shrimp (Penaeus dourarum) LC50 = 0.04 Mortality MRID 5005824/Acceptable

Reproduction and Growth Not
Available Pink shrimp (Penaeus
dourarum NOAEC = 0.013 Not Available Estimated (5)

Sediment Toxicity (6) Amphipod ( Leptocheirus plumulosus) 28-d NOAEC = 1.58 Growth 46929001 / Supplemental

Aquatic Non Vascular Plants

Survival and Growth non-vascular Green alga (Pseudokirchneriella subcapitatum) EC50 = 428 Growth (Based on cell counts) DeLorenzo et al. 2002 (ECOTOX 65915)/Supplemental
Aquatic Vascular Plants

Survival and Growth No acceptable data indentified

(1) Freshwater fish are used as a surrogate for aqua tic-phase amphibians because no acceptable data for quantitative use currently exist for endosulfan to aquatic-phase amphibians.
(2) The fathead minnow ( Pimephales promelas ) acute to chronic ratio (ACR = 4.3) was used to estimate a common carp chronic toxicity value because it is the most acutely sensitive freshwater fish species and no chronic toxicity data are available for it.
(3) The daphnid ( Daphnia magna ) acute to chronic ratio (ACR = 61.5) was used to estimate a freshwater shrimp chronic toxicity va lue because it is the most acutely sensitive freshwater invertebrate species and no chronic toxicity data are available for it.
(4) The sheepshead minnow ( Cyprinodon variegatus ) acute to chronic ratio (ACR = 2.0) was used to estimate a spot chronic toxicity value because it is the most acutely sensitive saltwater fish species and no chronic toxicity data are available for it.
(5) The mysid shrimp ( Americanmysis bahia ) acute to chronic ratio (ACR = 3.1) was used to estimate a spot chronic toxicity value because it is the most acutely sensitive saltwater invertebrate species and no chronic toxicity data are available for it.

(6) Sediment toxicity values are for endosulfan sulfate in sediment pore water.



### Toxicity to fish and aquatic invertebrates is categorized using the system shown in Table
4.2 (U.S. EPA, 2004). Toxicity categories for aquatic plants have not been defined.

107Table 4.2 Categories of Acute Toxicity for Fish and Aquatic Invertebrates

LC 50 (ppm) Toxicity Category

< 0.1 Very highly toxic

> 0.1 - 1 Highly toxic

> 1 - 10 Moderately toxic

> 10 - 100 Slightly toxic

> 100 Practically nontoxic



### 4.1.1 Toxicity to Freshwater Fish and Aquatic-Phase Amphibians

A summary of acute and chronic toxicity of endosulfan to freshwater fish and aquaticphase amphibians, including th e toxicity of the primary de gradate of concern (endosulfan sulfate), is provided below in Sections 4.1.1.1 through 4.1.1.6

.

4.1.1.1 Freshwater Fish: Acute Exposure (Morta lity) Studies – Registrant submitted

The acute toxicity stud ies available to the Agency dem onstrate that endosulfan can be classified as very highly toxic to freshwat er fish, with LC50 values ranging from 0.37 to
3.3 μ g a.i./L (see Appendix J for details). The studies also demonstrate that the formulated end use products w ith at least 33% a.i. are of similar acute toxicity to freshwater fish (LC50 values from 0.47 to 5.6 μ g a.i./L) as the TGAI. One formulation containing only 4% endosulfan was substantia lly less acutely toxic to freshwater fish (LC50 of 28 μ g a.i./L).

4.1.1.2 Freshwater Fish: Acute Exposure (M ortality) Studies—Open Literature

In addition to the acute toxicity studies di scussed above, several ac ute toxicity studies
with freshwater fish were identi fied from the open literature (see Appendix J ) which report more sensitive values. The lowest of these more sensitive acute LC50 values is 0.1

μ g a.i./L (Sunderam et al. 1992; ECOTOX reference #5850) for the common carp, Cyprinus carpio. This study was evaluated and consid ered supplemental but appropriate for quantitative use in this risk assessment. Therefore, an acute LC50 value of 0.1 μ g a.i./L will be used to quantitatively estimate acute risk to freshwater fish. Since no acute mortality studies with aquatic-phase amphi bians in the open literature have been identified as acceptable for quantitative use with in the context of this risk assessment, the
most sensitive LC50 value for freshwater fish will also be used to estimate acute risks to aquatic-phase amphibians.

4.1.1.3 Freshwater Fish: Chronic Exposure (Growth/Reproduction) Studies

Two acceptable life-cycle studies on fathead minnows ( Pimephales promelas ) were available to the Agency to evaluate the eff ects of chronic exposure to endosulfan (99% a.i.) on freshwater fish (MRID 05008271, 45868601). The first study (MRID 05008271) demonstrated that chronic exposur e to concentration as low as 0.40 μ g a.i./L has the potential to cause reproduc tive toxicity. Only 1% of the eggs hatched at this concentration (see Appendix J for details). The NOAEC and LOAEC for this study are
0.20 and 0.40 μ g a.i./L. The second study (MRID 45868601) demonstrated a reduction in

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### the reproduction and growth of fathead minnows at 0.11 μ g a.i./L and a NOAEC at 0.056

μ g a.i./L. Although these studies are considered acceptable, a fathead minnow acute to chronic ratio (ACR = 4.3) was used to estim ate a common carp chronic toxicity value because carp is the most acutely sensitive freshwater fish species (i.e., about a factor of 10 more sensitive than fathead minnow) and no chronic toxicity data for endosulfan are available for it. The estimated chronic NOAEC value for the common carp was
calculated as follows:

Acute fathead minnow/chronic fathea d minnow= acute carp/chronic carp

Where:

the acute fathead minnow value is based on the LC50 value 0.86 μ g a.i./L (MRID 05008271),

the chronic fathead minnow value is based on the NOAEC of 0.20 μ g a.i./L from the same study and,

the acute common carp value is based on the LC50 is 0.1 μ g a.i./L as described previously (Sunderam et al. 1992; ECOTOX reference #5850).

Therefore, 0.86/0.20 = 0.1/X

and,

Estimated common carp NOAEC = (0.20 x 0.1)/0.86 = 0.023 μ g a.i./L.

This estimated NOAEC of 0.023 μ g a.i./L for common carp will be used to quantitatively
estimate chronic risk of endosulfan to fres hwater fish. Since no chronic studies with aquatic-phase amphibians in the open literat ure have been identif ied as acceptable for quantitative use within the c ontext of this risk assessment, the estimated NOAEC of
0.023 μ g a.i./L for freshwater fish will also be used to estimate chronic risk to aquaticphase amphibians.

4.1.1.4 Freshwater Fish: Sublethal Effects and Additional Open Literature
Information

No additional acceptable studies from the open literature were identified for freshwater
fish that: established more sensitive acute or chronic endpoints than the data listed above; filled critical data gaps; presented a toxi city profile for under-represented taxa (e.g., toxicity data for amphibians); or provided in formation on sub-lethal effects that could be clearly and reasonable linke d to relevant assessment endpoints (i.e., survival, reproduction, and growth) at concentrations lower than the most sensitive endpoints used to quantitatively evaluate risk.

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### 4.1.1.5 Aquatic-phase Amphibian: Ac ute and Chronic Studies

No toxicity data for aquatic-phase am phibians were identified among the submitted studies or that were considered acceptable fo r quantitative use in th is risk assessment.

4.1.1.6 Freshwater Fish: Endosulfan Sulfate

Available data indicates that endosulfan sulfate is of similar acute toxicity to freshwater fish as the TGAI. Specifically, the 96-hour LC50 of endosulfan sulfate on bluegill was

3.8 μ g/L and is considered very highly toxic (MRID 46382604; Appendix J ). Acute toxicity testing of endosulfan sulfate (99.9% radiopurity) was also tested with common carp (MRID 45421402), which also indicated that the degradate is very highly toxic (96-
hr LC50 = 2.2 μ g/L) to freshwater fish. The study wa s classified as supplemental since it failed to comply with EPA’s recommended species and testing conditions. However, results from the submitted and open literature studies are consistent with studies of parent endosulfan TGAI where 96-hr LC50 values ranged from 0.37 to 3.3 μ g/L.

4.1.2 Toxicity to Freshwater Invertebrates

A summary of acute and chroni c freshwater invertebrate to xicity data, including data published in the open literature is pr ovided below in Sections 4.1.2.1 through 4.1.2.6.

4.1.2.1 Freshwater Invertebrates: Acute Exposure Studies

The acute toxicity stud ies available to the Agency dem onstrate that endosulfan can be classified as very highly t oxic or highly toxic to freshwat er invertebrates, with EC50 values ranging from 2.3 to 166 μ g a.i./L. (see Appendix J ). There were no studies submitted to the Agency on the effect of commercial end use products on freshwater
invertebrates.

4.1.2.2 Freshwater Invertebrates: Acute Exposure Studies—Open Literature

In addition to the aforementioned acute morta lity studies with freshwater invertebrates, several additional studies (see Appendix J ) reported more sensitive values. Two species of mayfly nymphs and one genus (species not indicated) of ca ddisfly larvae were tested
in static tests in which the concentrations of endosulfan were measured at the beginning of each test (Leonard, et al. 1999; ECOT OX reference #20012. The EC/LC50s using technical grade endosulfan in this study ranged from 0.4 to 1.8 μ g/L, varying based on the size of the organisms and the duration of the specific test. The lowest value was for caddisfly larvae ( Cheumatopsyche sp.); however, since this organism was not identified to species this datum will not be used. The next lowest value was for the mayfly Atalophlebia australis. The 0.6 μ g/L value for A. australis is considered the lowest acute
value for freshwater invertebrates that is acceptable for quantitative use in this risk assessment. There was one study from the open l iterature that indica ted for at least two species ( Daphnia magna and Hyalella azteca ) commercial end use pr oducts are not more

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### toxic than endosulfan applied as the T GAI (Wan et al. 2005 ; ECOTOX reference # 87973).

4.1.2.3 Freshwater Invertebrates: Chronic Exposure Studies

One chronic exposure study with endosulfan TGAI involving the freshw ater invertebrate, Daphnia magna, was submitted to the Agency (MRID 5008271). The study examined the effects of endosulfan on three consecutive ge nerations of daphnids and noted that the poor survival of third generation in the control and the lowest treatment group (2.7 μ g/L) precluded drawing valid conclu sions about the cumulative eff ects of exposure. However, the first generation portion of this study is c onsidered acceptable fo r quantitative use in this risk assessment, and generally coincide s with the duration and design of the current OPPTS Guideline (OPPTS 850.1300). The NOAEC and LOAEC from the first generation of this study are 2.7 and 7.0 μ g a.i./L based on reduced survival. Although this study is considered acceptable, a daphnia acute to chronic ratio (ACR = 61.5) was used to estimate a chronic value for the more acutely-sensitive mayfly, Atalophlebia australis. No chronic toxicity data are available fo r this species. The estimated chronic NOAEC value for the mayfly was calculated sim ilarly to that for the common carp above:

Estimated freshwater mayfly NOAEC = (0.6 x 2.7)/166 = 0.01 μ g a.i./L.

This estimated NOAEC of 0.01 μ g a.i./L for mayflies will be used to quantitatively
estimate chronic risk to freshwater invertebrates.

4.1.2.4 Freshwater Invertebrates: Sub-leth al Effects and Additional Open
Literature Information

No additional acceptable studies from th e open literature, beyond the one already discussed, were identified for freshwater invertebrates that: established more sensitive acute or chronic endpoints than the data listed above; filled critical data gaps; presented a toxicity profile for under-represented taxa; or provided information on sub-lethal effects that could be clearly and reasonably linke d to relevant assessment endpoints (i.e., survival, reproduction, and growth) at concen trations lower than the most sensitive endpoints used to quantitatively evaluate risk to freshwater invertebrates.

4.1.2.5 Freshwater Invertebrate s: Endosulfan Sulfate

Acute toxicity testing endosulfan sulfate using Daphnia magna (99.4% active ingredient) indicated that the degradate is highly t oxic (EC50 = 300 ug/L) to water fleas (MRID 45421403). The study was classified as suppl emental since it was conducted using a water hardness (160 - 180 mg/L as CaCO 3 

### ) outside of the recommended range (40 - 49 mg/L as CaCO 3 

### ). These results are similar to the acute toxicity of the parent TGAI to D. magna (166 ug/L; MRID 5008271; Appendix J ).

No data were identified on the chronic toxi city of endosulfan sulfate to freshwater
invertebrates that were considered acceptable for quantitative use in this risk assessment.

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### 4.1.2.6 Freshwater Invertebrates: Sediment Toxicity

Endosulfan sulfate sediment toxicity tests were conducted for the midge, Chironomus

tentans , in two studies. The 20-day NOAEC and LOAEC determined from pore water
were measured as 0.35 and 1.2 μ g/L respectively, based on mortality and percent emergence (MRID 47318101). In a second study cl assified as supplemental, the most
sensitive NOAEC and LOAEC were determined as 2.7 and 3.8 μ g/L, respectively based on growth (MRID 46382605).

4.1.3 Toxicity to Estuarine/Marine Fish

Although direct and indirect effects to the listed sp ecies are not dependent on estuarine/marine fish, toxicity data for es tuarine/marine were reviewed in order to provide a broader characterization of endosul fan risks to fish. A summary of acute and chronic estuarine/marine fish data, includi ng data published in the open literature is provided below in Sections 4.1.3.1 through 4.1.3.4.

4.1.3.1 Estuarine/Marine Fish: Acute Exposure (Mortality) Studies

The acute toxicity studies submitted to the Agency demonstrate that endosulfan can be classified as very highly toxic to estuarin e/marine fish, with LC50 values ranging from
0.09 to 0.38 μ g a.i./L for four species of fish (str iped bass, striped mullet, pinfish and
spot; see Appendix J ). No acceptable acute toxicity studies were available for estuarine/marine fish using formulated e nd-use products. The most sensitive acute LC50
value of 0.09 μ g a.i./L for spot, Leiostomus xanthurus (MRID 5005824) will be used to quantitatively estimate acute risk to estuarine/marine fish..

4.1.3.2 Estuarine/Marine Fish: Acute Exposure (Mortality) Studies—Open
Literature

In addition to the aforementioned acute morta lity studies with estuarine/marine fish an additional study was identified in the open lite rature which reported several LC50 values for sheepshead minnows ( Cyprinodon variegatus), the preferre d test species (Schimmel 1981; ECOTOX reference # 3740). This study wa s a report listing the results of an interlaboratory comparison of acute toxicity tests using estuarine animals—sheepshead minnow was one of the species tested. Th ere were six acute LC50 values based on measured, flow-through tests ranging from 0.34 to 1.15 μ g a.i./L (see Appendix J ).
While none of these values is lower than the LC50 for the spot listed above, their geometric mean (0.76 μ g a.i./L) will be used to establis h the acute to chronic toxicity
ratio for estuarine/marine fish used in the next section.

4.1.3.3 Estuarine/Marine Fish: Chronic Ex posure (Growth/Reproduction) Studies

No acceptable chronic toxicity data were avai lable to the Agency for estuarine/marine fish; however, there was a study from the open literature (Hansen and Cripe 1991; ECOTOX 115297) summarizing an interlaborat ory comparison of the early-life stage

112

### toxicity test using the sheepshead minnow Cyprinodon variegatus . Ten tests conducted with measured, flow-through exposures were reported with NOAECs ranging from 0.17
to 1.2 μ g a.i./L. The corresponding LOAECs are base d on either survival or growth (see Appendix J ). The geometric mean of these ten values is 0.38 μ g a.i./L. This study fulfills a data gap for a chronic test with the prefe rred estuarine/marine fi sh. Although these tests are considered acceptable for quantitative use in this risk assessment, a sheepshead minnow acute to chronic ratio (ACR = 2.0) was used to estimate a spot chronic toxicity value because it is the most acutely sensitive estuarine/marine fish species by approximately a factor of four compared to sheepshead minnow and no chronic toxicity
data for endosulfan are available for it. Th e estimated chronic NOAEC value for the spot was calculated similarly to that demonstrated above for the common carp (except with the ACR from the sheepshead minnow).

Estimated spot NOAEC = (0.09 x 0.38)/0.76 = 0.045 μ g a.i./L.

This estimated NOAEC of 0.045 μ g a.i./L for spot will be used to quantitatively estimate
chronic risk to estu arine/marine fish.

4.1.3.4 Estuarine/Marine Fish: Endosulfan Sulfate

One submitted study was available that evaluate d the acute toxicity of endosulfan sulfate on estuarine/marine fish. This study wa s conducted with sheepshead minnow and
resulted in a 96-hr LC50 of 3.1 μ g/L for endosulfan sulfate (MRID 46382603). This value is comparable to the range of LC 50s for the TGAI with sheepshead minnow
discussed above.

4.1.4 Toxicity to Estuarine/Marine Invertebrates

A summary of acute and chronic estuarine/ma rine invertebrate data, including data published in the open literature, is pr ovided below in Sections 4.1.4.1 through 4.1.4.5.

4.1.4.1 Estuarine/Marine Invertebrates: Acute Exposure (Mortality) Studies

The acute toxicity stud ies available to the Agency dem onstrate that endosulfan can be classified as highly toxic to very highly toxic to estuarine/ marine invertebrates, with LC50 values ranging from 0.04 to 790 μ g a.i./L (see Appendix J ). There was one study
available that used a formulated end-use product and demonstrated that for the brown shrimp that formulated endosulfan can be clas sified as very highly toxic with an LC50 of
0.24 μ g a.i./L (MRID 1328). The most sensitive LC50 value of 0.04 μ g a.i./L (MRID 5005824) for pink shrimp ( Penaeus dourarum ) is considered acceptable for quantitative
use to estimate acute risks to estuarine/marine invertebrates.

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### 4.1.4.2 Estuarine/Marine Invertebrates: Ac ute Exposure (Mortality) Studies—Open
Literature

In addition to the aforementioned acute mo rtality studies with estuarine/marine invertebrates, an additional study was identi fied in the open literature which reported several LC50 values for mysids ( Americamysis bahia; Schimmel 1981; ECOTOX reference # 3740). This study reported the resu lts of an interlaboratory comparison of acute toxicity tests using estuarine animals. There were five acute LC50 values based on measured, flow-through tests ranging from 0.38 to 1.29 μ g a.i./L (see Appendix J ).
While none of these values is lower than th e LC50 for the pink shrimp listed above, their geometric mean (0.83 μ g a.i./L) will be used to establis h the acute to chronic toxicity
ratio for estuarine/marine invertebra tes used in the next section.

4.1.4.3 Estuarine/Marine Invertebrates: Chronic Exposure (Growth/Reproduction)
Studies

No acceptable chronic toxicity data were avai lable to the Agency for estuarine/marine
invertebrates with the endos ulfan TGAI; however, one study was identified from the open literature (McKenney 1982; ECOTOX reference #3736) that summarized an interlaboratory comparison of chroni c toxicity tests using the mysid Americamysis bahia

. Five tests were conducted under measure d, flow-through conditions with reported NOAECs ranging from 0.14 to 0.52 μ g a.i./L. The corresponding LOAECs were based primarily on survival (see Appendix J ). The geometric mean of these five values is 0.27

μ g a.i./L. The study fulfills a data gap for a ch ronic test with a preferred estuarine/marine invertebrate. Although these tests are consider ed acceptable for quant itative use in this risk assessment, a mysid acute to chronic ra tio (ACR = 3.1) was used to estimate a pink shrimp chronic NOAEC because it is the mo st acutely sensitive estuarine/marine invertebrate species (i.e ., by approximately a factor of 10 compared to Americamysis
bahia ) and no chronic toxicity data for endos ulfan are available for pink shrimp. The estimated chronic NOAEC value for the pink sh rimp was calculated similarly to that demonstrated above for the common carp (e xcept with the ACR from the mysid).

Estimated pink shrimp NOAEC = (0.04 x 0.27)/0.83 = 0.013 μ g a.i./L.

This estimated NOAEC of 0.013 μ g a.i./L for pink shrimp w ill be used to quantitatively
estimate chronic risk to estuarine/marine invertebrates.

114

### 4.1.4.4 Estuarine/Marine Invertebra tes: Open Literature Data

No additional acceptable studies from the open literature were identified for
esturarine/marine invertebrate s that: establish more sensi tive acute or chronic endpoints than the data above; filled critical data gaps; presented a toxi city profile for underrepresented taxa; or provided information on su b-lethal effects that could be clearly and reasonably linked to relevant assessment endpoints (i.e., survival, reproduction, and growth) at concentrations lower than the mo st sensitive endpoints used to quantitatively
evaluate risk.

4.1.4.5 Estuarine/Marine Inverteb rates: Endosulfan Sulfate

A 28-d flow-through, measured chro nic toxicity study of the e ffects of endosulfan sulfate was conducted with the mysid, Americamysis bahia (MRID 46781601). Endpoints measured included survival, growth (len gth and dry weight), and reproduction (offspring/female/day). The most sensitive e ndpoint from this study was dry weight of male mysids, with a NOAEC and LOAEC of 0.38 and 0.73 μ g ai/L, respectively. This NOAEC is similar to those reported by Mc Kenney et al 1982 (ECOTOX reference # 3736) described above (0.14 to 0.52 μ g a.i./L). This study is considered supplemental because raw data were not provided, terminal growth measurements were not conducted and a minor discrepancy was identified in th e reported survival of control organisms.

4.1.5 Toxicity to Aquatic-phase Amphibians—Open Literature

A number of studies involvi ng amphibian toxicity testing and endosulfan were identified in the open literature and are summarized be low. None of these studies provide reliable estimates of toxicity that may be used qua ntitatively in this risk assessment; however, they do provide some information regarding the hazard of endosulfan to amphibians. For a comprehensive consideration of all potential effects data and additional information for amphibians please refer to the detailed sp readsheet of the available ECOTOX open
literature data that can be found in Appendix H

.

Bernabò, et al. (2008 ; ECOTOX referen ce # 103223) and Brunelli, et al. (2009) evaluated the effect of endosulfan (99% purity) on ta dpoles of the common toad Bufo bufo. Four-day-old tadpoles were exposed for 96 hr in a static test. The 96 hr LC50 value
based on nominal concentrations was 430 μ g/L (Bernabò, et al. (2008) . In a separate test, exposure to 200 μ g/L endosulfan resulted in an appare nt increase in mucus production by the gills, as well as inflammation of the gills . These changes occurred after only 24 hr and became more pronounced as the exposure continued (Bernabò, et al. 2008). The same group continued their work with endosulfan and this toad species looking for behavior and morphological differences, after much longer (43-53 days) exposure durations (Brunelli, et al. 2009). Three concentrations and a control were used. There were no statistically significant differen ces between the control and 10 μ g/L for survival, the rate of deformity or the number of toads metamor phosed (into Gosner stage 46—complete tail resorption). However, there was 77% and 97% mortality at 50 and 100 μ g/L,

115

### respectively. In addition, 100% of the surviving tadpoles ex hibited various degrees of deformity and none of the survivors reach stage 46.

Several papers evaluated the e ffect of endosulfan on tadpoles of Australian frogs, but all
were unmeasured tests. Broomhall (2002; ECOTOX reference # 65732) exposed tadpoles of Litoria citropa to a single 0.8 μg/L nomina l concentration of endosulfan (Thiodan) under two different temperature regime s, one more variable than the other over the 96 hr test. At ambient temperatures (ca. 20 C) the survival was 89% in the endosulfan treatment (100% in the control). Under a sim ilar average temperature, but more variable, only 58% of the tadpoles survived, compared to 92% in the controls. After termination of the above test, all surv iving tadpoles were tran sferred to clean water and held at 19 C for 24 days. These tadpoles were then evaluate d for their ability to avoid predation by
odonates. The endosulfan treated animals were more vulnerable to predation, measured by a significant decrease in the number of minutes elapsed until capture.

Broomhall and Shine (2003; ECOTOX re ference # 71866) exposed tadpoles of the Australian treefrog Litoria freycineta to two different concen trations of endosulfan (source not given, but assume was same as Broomhall (2002)—Thiodan). There was no effect on survival after 96 hr exposure to 0.03 or 1.3 μ g/L a.i. relative to the controls. However, exposed tadpoles grew more slow ly than controls—alt hough not statistically significant. And the survivors at the higher concentration were cap tured and consumed by odonate predators (dragon fly larvae) signifi cantly sooner when tested 15 days after
transfer to clean water. Broomhall (2004; ECOTOX reference #73400) completed another series of experiments similar to the above, usi ng the same exposure concentrations with a different species, Limnodynastes peronii , with similar results.

Canadian frogs were evaluated based on unm easured concentrations. Green frog eggs and larvae ( Rana clamitans) were exposed to two diff erent scenarios using Thiodan 50WP (Harris, et al. 1998; ECOTOX reference #19300). In the first test series, Gosner stage 8 embryos through to stage 25 tadpoles were continuously exposed to a treatment for 13 days (two-thirds renewal of treatment solu tions every second day). The 96 hr LC50 was greater than the highest c oncentration tested (11,750 μ g/L a.i.); however, the 13 day
LC50 was 15 μ g a.i. /L—suggesting that the earl ier embryonic stages were not as sensitive to endosulfan. Note, hatching occurr ed around day eight of the test. A second set of exposures in this study consisted of th e same exposure for the first 4 days, then a period of 7.5 days in reference water, follo wed by a second 4-day exposure to the same concentrations. The 96 hr LC50 was again a greater than, and the 16 day LC50 was the same as that in the first test. The frequency of deformities at hatch also was calculated in the second test, resulting in an EC50 of 2,430 μ g a.i./L.

The toxicity of Thiodan 4EC ( 40% emulsified concentrate) was evaluated (Berrill et al. 1998; ECOTOX reference # 19467) with newly hatched and two-week-old tadpoles of the wood frog ( Rana sylvatica ), the American toad ( Bufo americanus ), and the green frog ( Rana clamitans ). Embryos of the wood frog were also tested, but were not as sensitive as tadpoles; therefore embryos of the other two species we re not tested. New hatched tadpoles of each species were exposed for 96 hr followed by a 10 day

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### recovery/observation period. Two-week of ta dpoles were likewise exposed for 96 hr, and followed for and additional 7 day recovery peri od in clean water. Water concentrations of endosulfan were measured, but only after th e first hour of the exposure period and the treatments were apparently not renewed. E xposure concentrations ranged from 32 to 364

μ g a.i. /L , depending on the life stage and sp ecies. There was essentially no mortality for either life stage for all three species during the first 96 hr; however, there was extensive postexposure mortality. Also, two-week old ta dpoles were more sensitive than newly hatched tadpoles—no LC50s were calculated.

Early stage tadpoles of Bufo melaanostictus, Limnonectes limnocharis and Microphyla

ornata were exposed to a commercial end-use product of endosulfan (35EC) in 96-h acute toxicity tests (Dey a nd Gupta 2002) The authors used 10 animals per container and three containers per treatment. The animals were collected from the field and acclimated for 3 to 4 days. They did not describe the chambers or the volume of water used. The source of the water was dechlorinated tapwater . Control mortality also was not described. The 96-h LC50s were based on nominal concentrations and are 20, 1.3 and 0.16 μ g/L, respectively, for the three species list ed above. The relative sensitivity of M. ornate is likely due to its much smaller size. This was the likely explanation for the sensitivity of this species to the pesticide dichlorvos and the herbicide butachlor (Geng et al. 2005).

Finally, there is a preprint avai lable that evaluates the growth and survival of the northern leopard frog Rana pipiens tadpoles (Shenoy et al. inpress) . They exposed four-day-old tadpoles to Endosulfan 3EC (33% a.i.) for seve n weeks. Each individual was placed into a separate 1.5 L of exposure medium with th e water changed every 3 days. There were 15
individuals used for each trea tment. Besides the controls, treatments were 0.2, 1 and 5

μ g/L of the active ingredient. Concentrations were not measured. Gr owth rate (length) was not affected in surviving tadpoles in any treatment relative to the controls. No LC50 values were calculated; however, there was 100% mortality by day 12 and day 28 in the 5
and 1 μ g/L treatments, respectively. Based on the authors’ Figure 1 the control survival was approximately 80% at the end of the seven weeks and that in the 0.2 μ g/L treatment approximately 40%. Although no 96 hr data were presented, the figure suggests that there was little of no mortality during the firs t 4 days of the experiment. Although not calculated by the authors the above data sugge st that the chronic LC50 would be close to
0.2 μ g/L.

4.1.6 Toxicity to Aquatic Plants

For the purposes of this assessment, plant acute EC50 values, rather than NOAEC values, are to be used to assess the potential for effects to the aquatic-phase CRLF, CTS, SFGS, BCB, VELB, SMHM and SJKF via indirect effects on habitat, cover, food supply, and/or primary productivity (i.e., aquatic plant co mmunity), because there are no obligate relationships between the asse ssed species and any aquatic plant species. There were no acceptable or supplemental data on the toxicity of endosulfan to aquatic vascular or nonvascular plants submitted to the Agency. There were several references available from

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### the open literature: however, only one of thes e could be considered as following methods suitable to be considered acceptable (DeL orenzo et al 2002; ECOTOX reference # 65915). This study reported the 96 hr EC50 for the green alga Pseudokirchneriella subcapitatum (formerly Selenastrum capricoratum ) using a standard ASTM protocol. This species is one of the OPP preferred species. The EC50 is 428 μ g/L based on nominal concentrations of technical grade endosulfan (98.6% a.i.). There were no acceptable data identified in the open literature for aquatic vascular plants.

4.1.7 Freshwater Field/Mesocosm Studies

There were no acceptable data submitted to the Agency on freshwater field or mesocosm studies with endosulfan. There were; howev er, two studies identified from the open literature (Hose et al. 2002; ECOTOX 62267; Hose et al. 2003; ECOTOX 72555). Both
studies used the same artificial stream e xperimental design using flow-though river water. The flow was stopped during the exposure phase of the experiments. In the first study the endosulfan (96% purity) was app lied as contaminated sediment slurries. The stream flow was blocked for 12 h after the initial expos ure, then flow was restored and the macroinvertebrate community sampled after an additional 96 h. There was no effect on
the structure of the macroinvertebrate commun ity at the highest concentration measured (6.14 μ g/L—interstitial waters of the gravel su bstrate). The authors state that laboratory
studies have shown that 12-h exposures to this concentr ation (without sediment) are toxic. However, they further conclude that th e presence of fine sedime nt in the interstitial water is likely to reduce the toxicity of endosulfan, presum ably by binding the pesticide and reducing its bioavailability. Although there were no effect s on the community structure due to endosulfan exposure, there we re differences in the number of individuals
in the downstream drift of the mesocosms for some of the taxa. For example, the mayfly Jappa kutera had increased numbers in the high-dos e streams relative to the controls, possibly as an avoidance mechanism.

These same authors conducted a similar study, but with aqueous endosulfan (Hose, et al 2003). Two separate experiments were ca rried out; a 12-h and a 48-h exposure (endosulfan was measured in the streams fo r each experiment). The first was a 12-h exposure, followed by and additional 96-h of observation. During the 12-h exposure the stream flow was stopped. Fifty taxa were recorded in the be nthic assemblages during this first experiment. The data were analy zed using principle response curves. The assemblages at 8.69 μ g/L and lower were not statistical ly different from the controls; however, the assemblages at the hi ghest concentration tested (48.87 μ g/L) were different from the controls—largely due to decreases in the abundance of seve ral key taxa. In the 48-h study endosulfan was added every 6 h for 48 h. During each 6-h exposure the stream flow was stopped. The water was renewed at the beginning of each 6-h exposure. The assemblages at 1.00 μ g/L were not statistically different from the controls; however, the assemblages at the higher con centration tested (6.87 and 30.70 μ g/L) were different from the controls—as above this was largely due to decreases in the a bundance of several key taxa. In this latter experiment the aut hors noted the appearan ce of blooms of the filamentous alga Spyrogyra sp. in the 6.87 and 30.70 μ g/L treatments after 13 d. No algae were noticed prior to the start of the experime nt and none were presen t in the controls or

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### 1.00 μ g/L treatments on day 13. The authors sugges ted that this was likely associated with an apparent reduction in the numbe r of tadpoles at these higher endosulfan concentrations—however, the numbers of tadpoles were not quantified.

4.2 Toxicity of Endosulfan to Terrestrial Organisms

Table 4.3 summarizes the most sensitive terrestrial toxicity endpoints, 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 is presented below.

Table 4.3 Terrestrial Toxicity Profile for Endosulfan

Assessment Endpoint Purity (% a.i.) Surrogate Species Toxicity Value Used for Quantitative
Risk Estimates (a.i.) Effects Reference/Acceptability

Birds, Terrestrial-phase Amphibians and Reptiles a

Survival 97.2 Mallard duck (Anas platyrhynchos) LD50 = 28 mg/kg Mortality MRID 136998/Acceptable

Survival 96 Northern bobwhite quail LC50 = 805 ppm Mortality MRID 22923/Acceptable

Reproduction and Growth 96 Mallard duck (Anas platyrhynchos) NOAEC = 30 mg/kg-diet LOAEC = 64 mg/kg-diet Eggs laid, eggs set, embryo viability MRID 40335001/A cceptable

Mammals

Survival Rat ( Rattus norvegicus ) LD50 = 10 mg/kg (female) LD50 = 40 mg/kg (male) Mortality MRID 00038307/Acceptable

Reproduction and Growth Rat ( Rattus norvegicus ) NOAEC = 15 mg/kg diet LOAEC = 75 mg/kg diet Decrease body weight MRID 00148264/A cceptable

Terrestrial Invertebrates

Survival 100 Beet webworm ( Pyrausta sticticalis ) 1 d LD50 = 0.15 ug a.i./g Mortality Leonova and Slunko
2004/ECOTOX 100430 Terrestrial Plants

Survival and Growth No acceptable data identified

a Birds are used as a surrogate for terrestrial-phase amphibians and reptiles because no acceptable data for quantitative use currently exist for endosulfan toxicity to these taxonomic groups.



### Acute toxicity to terrestrial animals is categ orized using the classi fication system shown
in Table 4.4 (U.S. EPA, 2004). Toxicity categories for terrestrial plants have not been
defined.

Table 4.4. Categories of Acute Toxicity for Avian and Mammalian Studies

Toxicity Category Oral LD 50 Dietary LC 50 Very highly toxic < 10 mg/kg < 50 ppm
Highly toxic 10 - 50 mg/kg 50 - 500 ppm
Moderately toxic 51 - 500 mg/kg 501 - 1000 ppm

Slightly toxic 501 - 2000 mg/kg 1001 - 5000 ppm
Practically non-toxic > 2000 mg/kg > 5000 ppm



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### 4.2.1 Toxicity to Birds, Reptiles, and Terrestrial-Phase Amphibians

As specified in the Overview Document, the Ag ency uses birds as a surrogate for reptiles and terrestrial-phase amphibians when toxi city data for each specific taxon are not available (U.S. EPA, 2004). A summary of acu te and chronic bird data, including data published in the open literature is pr ovided below in Sections 4.2.1.1 through 4.2.1.4.

4.2.1.1 Birds: Acute Exposure (Mortality) Studies

The results of the acute oral t oxicity studies (MRID 137189, 136998, and 160000) available for endosulfan (see Table 4.5 and Appendix K ) indicate that endosulfan can be classified as moderately toxic to highly toxic to avian species on an acute oral basis with LD50 values for Northern bobwhite quail ( Colinus virginianus ), Mallard duck ( Anas platyrhynchos ), and Ring-necked pheasant ( Phasianus colchicus ) ranging from 28 to > 320 mg a.i./kg-body weight. Based on all of th e acute oral toxicity data, mallard ducks were the most acutely sensitive with LD50 values ranging from 28 to 45 mg a.i./kg-body weight. The LD50 value of 28 mg a.i./kg-body we ight will be used in the quantitative
estimate of risk.

The results of the single sub-acute dietar y toxicity study (MRID 22923) available for
endosulfan indicate that it can be classified as slightly toxic to moderately toxic with LC50 values for Northern bobwhite quail ( Colinus virginianus ), Mallard duck ( Anas platyrhynchos ), Ring-necked pheasant ( Phasianus colchicus ), and Japanese quail ( Coturnix japonica ) ranging from 805 to 1275 mg a.i. /kg-diet. Northern bobwhite quail was the species tested with the lowest valu e. The LC50 value of 805 mg a.i./kg-diet will be used in the quantitative estimate of risk.

Table 4.5 Comparison of Acute Toxicity of Endo sulfan and Endosulfan Sulfate To Birds.

Acute Oral Toxicity Acute Dietary Toxicity

Endosulfan Endosulfan Sulfate Endosulfan Endosulfan Sulfate

Species LD 50 (ppm) Toxicity Category (MRID) LD 50 (ppm) Toxicity Category (MRID) 5-day
LC 50 (ppm) Toxicity Category (MRID) 5-day
LC 50 (ppm) Toxicity Category (MRID)

Northern bobwhite quail Colinus virginianus -- -- 44 highly
toxic (464305- 01) 805 moderately
toxic (22923) >3528 (46430502)
(a)

Mallard duck Anas platyrhynchos 28 highly
toxic (136998) --- --- 1053 slightly toxic (22923) 1642 slightly
toxic (463826- 01) (a) Study classified as supplemental.



### 4.2.1.2 Birds: Chronic Exposure (Gro wth, Reproduction) Studies

Three avian reproduction studi es with mallard ducks ( Anas platyrhynchos ) and Northern bobwhite quail ( Colinus virginianus ) have been submitted to the Agency for endosulfan (MRID 146843, 40335001, and 40335002). Only one te st established both NOAEC and LOAEC values (see Appendix K ). This test was a 22 week study with mallard ducks

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### ( Anas platyrhynchos ). The NOAEC was 30 ppm and the LOAEC was 64 ppm (using measured dietary concentrati ons), based on number of eggs laid (53% of control) and embryo viability (52% of control) (MRID 40335001). The other mallard duck test had an NOAEC < 30 ppm (MRID 146843) and was not used because the measured dietary concentrations were not presented. The bobw hite quail test showed an NOAEC = 64 ppm and an LOAEC = 134 ppm. The results of thes e studies indicate that endosulfan may have adverse effects on avian reproduction at higher levels of exposure, and the most sensitive NOAEC of 30 ppm (mg a.i./kg-diet) will be used to quant itatively estimate the risks to birds (and thus, terrestrial-phase am phibians and reptiles) resulting from chronic exposure to endosulfan.

4.2.1.3 Birds: Open literature Studies

No additional acceptable studies from the open literature were identified for birds (or terrestrial-phase amphibians or reptiles) that: established more sensitive acute or chronic endpoints than existing data; fi lled critical data gaps; pres ented a toxicity profile for under-represented taxa (e.g., toxicity data fo r amphibians or reptiles); or provided
information on sub-lethal effects that could be clearly and reasonably linked to relevant assessment endpoints (i.e., survival, reproductio n, and growth) at concentrations lower than the most sensitive endpoints us ed to quantitatively evaluate risk.

4.2.1.4 Birds: Endosulfan Sulfate

Based on the comparison of parent endosul fan TGAI with the endosulfan sulfate degradate using acute dietary LC50s for bobwhite quail and mallard duck, endosulfan sulfate appears about equal in toxicity to waterfowl (mallard ) and at least a factor of 4 less toxic to game birds (quail; Table 4.5 ). No chronic avian studies were identified for
endosulfan sulfate that were considered acceptable for quantitative use in this risk

assessment.

4.2.2 Toxicity to Mammals

Typically, mammalian toxicity data from the Agency’s Health Effects Division (HED) are used to approximate toxicity to mammals . However, wild mammals toxicity tests may be required on a case-by-case basis, depend ing on the results of the lower tier studies such as acute and sub-acute testing, intende d use pattern, and pert inent environmental fate characteristics. No studies evaluating to xicity to wild mammal species have been submitted by the registrants for endosulfan. A summary of acute and chronic mammalian data, including data published in the open literature, is provi ded below in Sections 4.2.2.1 through 4.2.1.3.

4.2.2.1 Mammals: Acute Exposure (Mortality) Studies

The acute oral LD50 values for the laboratory rat ( Rattus norvegicus ) were 10 and 40 mg/kg for females and males, respectively (MRID 38307). Since acute toxicity estimates fall in the range of 10 to 50 mg/kg, endosulfan is classified as hi ghly toxic on an acute

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### exposure basis (see Appendix K for more detail). Additional data from the open literature support the conclusion that female rats are more sensitive to endosulfan than males (Gupta 1976; ECOTOX 103467). LD50s for males were greater than those for females by about a factor of 2. The LD50s fr om the submitted data are still the lowest numbers. Gupta (1976) also pr esented LC50 data for mice ( Mus musculus ). Unlike rats,
there were no differences in LD50s between male and female mice. However, mice were
more sensitive than rats in there stud y. Values ranged from 6.5 to 13.5 mg/kg body weight for mice (and 22.1 to 89.4 for rats), depending on the vehicle used to administer the endosulfan (see Appendix K ). The acute oral LD50 value 10 and 40 mg/kg for females and male rats, respective will be used to estimate the risk to mammals from acute exposure to endosulfan. The lower value fo r the mouse was not used because the exposure was via intraper itoneal injection rather than through diet.

4.2.2.2 Mammals: Chronic Exposure (Growth, Reproduction) Studies

A two-generation rate repr oduction study measured the NOAEC and LOAEL as 15 and 75 ppm, respectively (MRID 148264), with decr eased body weight as the most sensitive endpoint (see Appendix K for more detail). An additional study from the open literature supports the conclusion from Gupta ( 1976; ECOTOX 103467) that mice are more
sensitive to endosulfan than rats. Hack et al. (1995; ECOTOX 103384) exposed groups of
rats and mice for 24 months to various concen trations of endosulfan in their diet. These
authors concluded that the NOAEC and LOAEC for rats are 15 and 75 ppm, respectively—based on final body weight for both males and females (there was no effect of endosulfan on rat survival). There was no effect of dietar y endosulfan on the growth of either male or female mice; however the authors’ data would list the NOAEC and LOAEL as 6 and 18 ppm, respectively—ba sed on survival of females.

Two other open literature studies using oral intubation showed that spermatogenesis in rats is reduced significantly at endosulfan doses as low as 2.5 mg/kg body weight after 70 days of exposure (Sinha et al. 1995; EC OTOX 103592), and that fetal survival and development can be impaired at concentra tions as low as 1.0 mg/kg body weight fed to sexually mature female rats on days 6 to 20 of their pregnancies (Singh et al. 2007; ECOTOX 103238).

4.2.2.3 Mammals: Endosulfan Sulfate

No acute or chronic mammalian studies were identified for endosulfan sulfate that were considered acceptable for quantitativ e use in this risk assessment.

4.2.3 Toxicity to Terrestrial Invertebrates

A summary of terrestrial invertebrate data, including data published in the open literature, is provided below in Sections 4.2.3.1 and 4.2.3.2.

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### 4.2.3.1 Terrestrial Invertebrates: Acut e Exposure (Mortality) Studies

The only Agency guideline acute study for te rrestrial invertebrate s is for the honey bee ( Apis mellifera ). A total of four honey bee studies (see Appendix K ) are available that include acute contact, acute or al and acute contact with tr eated foliage with TGAI and formulated end use product (MRIDs 1999, 05004151, 05008936, and 05012881). The
acute contact LD50 va lues are 4.5 and 7.1 μ g a.i./bee, both with TGAI. The sole acute
oral LD50 is 6.9 μ g a.i./bee, also with TGAI. Two st udies reported exposures based on
foliar residues. Both studies observed little to no mortality at the highest concentrations tested, making the LC50s > 7.1 and >1.10 lb /acre. The acute contact LD50 of 4.5 μ g a.i./bee is multiplied by 1 bee/0.128g, which is based on the weight of an adult honey bee, in order to estimate the toxicity in terms of ppm ( μ g a.i./g of bee).

No additional data on the effects of endosulfa n to non-target terrestrial invertebrates was submitted to the Agency.

4.2.3.2 Terrestrial Invertebrates: Open Literature Studies

The ECOTOX database was examined for toxi city data using non-ta rget species with endpoints expressed in terms similar to those for the standard test with honey bees. The stingless bee and the Indian honey bee were bot h more sensitive than the standard honey bee in comparable tests based on per bee exposure (see Appendix K ). However, both the stingless bee and the Indian honey bee are sm aller than the standard honey bee so the conversion used for the honey bee in the last section (1/0.128 g/bee) should not be used.
Data from the test us ing the stingless bee Trigona spinipes (Macieira and HebllingBeraldo 1989; ECOTOX reference #51755) is the lowest LC50 (0.21 μ g a.i/bee). Three
different foliar residue studies using three different species of parasitic wasps also are
listed in Appendix K . Significant mortality occurred at the reported application rates (0.50 to 1.50 lb/a).

Several studies listed in the ECOTOX databa se used earthworms as the test organism. Mosleh et al (2003; ECOTOX reference # 86741; note this is the same data that the authors also report in Mosleh et al. 20 02; ECOTOX reference #87129) report LC50s using a commercial end-use product mixed with natural soil for the earthworm Lumbricus

terrestris . The LC50s declined as the duration of exposure increased, and ranged from 3.36 to 12.29 mg endosulfan/kg soil.

There are numerous studies available from the open literature relative to targeted insect
studies. The data from studies which calcula ted contact, oral or foliar residue acute LD50s are presented in Appendix K . Most of these data ar e larvae of several moth species. Two studies (Leonova and Slynko 1996, 2004; ECOTOX references #103049 and 100430) showed that at least for the co tton bollworm and the beet webworm adult
moths more sensitive that the larvae of thes e species. As expected, overall these studies show that applications of formulated endos ulfan are likely to reduce the numbers and possibly eliminate populations of arthropods. The lowest acute contact LD50 or 0.15 μg/g (ppm) for the adult moth of the beet webworm ( Pyrasta sticticalis) will be used to

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### estimate the risk to terrestrial inverteb rates from acute exposure to endosulfan.

4.2.4 Toxicity to Terrestrial Plants

No data have been submitted to the Agency to evaluate the effects of endosulfan on terrestrial plants because historically, terrestr ial plant toxicity studies and associated risk analysis of plants were not required for re gistration of a pesticide unless it met specific use and pesticide classification criteria wh ich would trigger potential concerns. In addition to the lack of registrant-submitte d data, no studies demonstrating significant
adverse effects of endosulfan to any terrestrial plant have been identified in the open literature. Although a number of studies involv ing terrestrial plants and endosulfan were identified in the open literature, none of these studies provide reliable estimates of toxicity that may be used in this risk assessment. Reasons that these studies were deemed unacceptable for use were primarily because th ese studies were associated with efficacy
determinations in which observations were confounded by the presence of an insect pest complex. As such, plants in these tests gene rally did not demonstrate any adverse effects at any test levels, but did not test up to the maximum allowable rate. For a comprehensive consideration of all potential effects data and additional information for terrestrial plants please refer to the detailed spreadsheet of the available ECOTOX open literature data that

can be found in Appendix H

.

4.3 Use of Probit Slope Response Relati onship to Provide Information on the Endangered Species Levels of Concern

The Agency uses the probit dose response rela tionship 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 th e listed species of concern (U.S. EPA, 2004). As part of the risk characterization, an inte rpretation of acute RQs for listed species is discussed. This interpretation is presented in terms of the chance of an individual event (i.e., mortality or immobilization) should expos ure at the EEC actually occur for a species with sensitivity to endosulfa n on par with the acute toxici ty 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 th at 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 es timate based on the mean, upper and lower estimates of the effects probability are also provided to accoun t for variance in the slope, if available.

Individual effect probabilitie s are calculated based on an Ex cel spreadsheet tool IECV1.1 (Individual Effect Chance Model Version 1.1) developed by the U.S. EPA, OPP, Environmental Fate and Effects Division (J une 22, 2004). The model allows for such calculations by entering the mean slope esti mate (and the 95% confidence bounds of that

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### estimate) as the slope parameter for the spr eadsheet. In addition, the acute RQ is entered
as the desired threshold.

4.4 Ecological Incident Summary

A review of the Ecological Incident Information System (EIIS) database for ecological incidents involving endosulfan was complete d on March 25, 2009. This database consists of exposure incident reports submitted to th e EPA from 1994 to present. A summary of ecological incidents involvi ng endosulfan are listed in Table L.1 in Appendix L . This
table is divided into incide nts involving aquatic organism s only, terrestrial organisms only, and both aquatic and terrestrial organism s. Within each of these sections of the table, incidents are orde red by date beginning with the earliest incident.

Incidents listed in EIIS are categorized by the likelihood that a particular pesticide is associated with that particular incident. Th ese classifications incl ude highly probable, probable, possible, unlikely or unrelated. “H ighly probable” incide nts usually require carcass residues or clear circumstances rega rding the exposure. “Probable” incidents
include those where residue information was not available or circumstances were less clear than those for “highly probable.” “P ossible” incidents occur when multiple chemicals may have been involved and the cont ribution of an individual chemical is not obvious. An “unlikely” incide nt classification is given when a given chemical is considered nontoxic to the type of organism involved or th e chemical was analyzed and not detected in samples. The “unrelated” category is used for incidents confirmed not to involve pesticides. No unrelated inci dents were listed for endosulfan.

The number of reports listed in the EIIS databa se is believed to be only a fraction of the total incidents involving orga nismal mortality and damage caused by pesticides. Few resources are assigned to incident reporting. Reporting by states is only voluntary, and individuals discovering incide nts may not be informed on the procedure of reportingthese occurrences. Additionally, much of the database is generated from registrantsubmitted incident reports. Registrants are lega lly required to provide detailed reports of only “major” ecological incidents involving pesticides, while “minor” incidents are reported aggregately. Because of these logist ical difficulties, EIIS is most likely a minimal representation of all pestic ide-related ecological incidents.

The EIIS database contained 83 incident reports involving endos ulfan. Most of the incidents involve aquatic ecosystems (75 or 90 % of the total incidents). Seven incident reports involve terrestrial ecosystems and one involves a combined aquatic/terrestrial ecosystem. California was most represented among all 50 states (26 reports) followed by North Carolina (9), Louisiana and South Caro lina (5 each) and Washington State (4).
Additional characteriza tion of these incidents is provided below.

Incident Certainty and Legality

Of the 83 incidents reported, 23 (28%) are categorized as ‘h ighly probable’ and 40 (48%) are categorized as ‘probable.’ Collectivel y the ‘highly probable’ and ‘probable’

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### categories represent 76% of the reported inci dents. Regarding the legal status, the
‘unknown’ and ‘misuse accidental’ represent the largest legali ty categories with 36% and 35% of the incident reports, respectively. Approximately 25% of the reports consist of registered uses. Lastly, only three of the in cident reports involved intentional misuse.

Of the 15 ‘highly probable’ and ‘probable’ incident reports th at involved only ‘registered uses,’ most described pesticide runoff followi ng periods of heavy rainfall as the likely event that led to the reported incident. The majority of the ‘highly probable’ and ‘probable’ incidents classified as ‘accidental misuse’ involv ed aerial application too close to bodies of water as stip ulated by the label, spills and equipment washing.

Aquatic Incidents

The vast majority of the aquatic incident repo rts involved mortality to fish (67), a highly sensitive taxonomic group. Only three incidents reportedly involved aquatic invertebrates, but the likeli hood of observing impacts to aq uatic invertebrates is low compared to fish. Of the 67 aquatic incident s involving fish, 53 (80 %) are classified as either ‘highly probable’ or ‘pr obable’ in the context of endosulfan use. A wide variety of fresh and estuarine species were reportedly affected (e.g., carp, catfish, largemouth bass, shad, menhaden, mullet, spot, bluegi ll sunfish, gar and trout).

Terrestrial Incidents

Of the seven terrestrial incide nts, none are classified as ‘highly probable’ and two are classified as ‘probable.’ The two ‘probable’ incidents involve birds (blue jay, crow, owl), mammals (squirrel, opossum, red fox) and an amphibian (unidentified frog).

Plant Incidents

Only one reported incident invo lved plants and this was clas sified as ‘possible,’ but the plant species was not identified.

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# 5 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, CTS, SFGS, SMHM, SJKF, BCB, and VELB or for modification to its designated critical habitat from the use of endosulfan in CA. The risk characterization provides an estimation ( Section 5.1 ) and a description ( Section 5.2 ) of the likelihood of adverse effects; articulates risk assessme nt assumptions, limitations, and uncertainties; and synthesizes an overall conclusion regardi ng the likelihood of adverse effects to the CRLF and other SFB species or their 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 e xposure to toxicity. This ratio is the risk quotient (RQ), which is then compared to pr e-established acute a nd chronic levels of concern (LOCs) for each category evaluated ( Appendix D ). For acute exposures to the aquatic animals, as well as terrestrial invert ebrates, the LOC is 0.05. For acute exposures to the birds (and, thus, reptiles and terrest rial-phase amphibians) and mammals, the LOC is 0.1. The LOC for chronic exposures to animals, as well as acute exposures to plants is
1.0.

Acute and chronic risks to aquatic organism s are estimated by calculating the ratio of exposure to toxicity using 1-in-10 year EECs, based on the label-recommended endosulfan usage scenarios, summarized in Table 3.5 and the appropriate aquatic toxicity endpoint from Table 4.1 . As described in Section 2.10.1 (Problem Formulation), aquatic exposures were modeled separately for the parent isomers ( ά and β ) and the primary degradate of concern (endosulfan sulfate). Th e resulting daily concentrations were then summed to form a 30-year time series for total endosulfan (sum of ά

, β and endosulfan sulfate). Due to similar acute toxicity and structure of the TGAI and endosulfan sulfate,
modeled or measured environmental e xposures of total endosulfan (sum of ά

, β and endosulfan sulfate) were compared with toxici ty data for the TGAI. For sediment-borne exposures, toxicity data were available only for endosulfan sulfate, and thus, comparisons
of total endosulfan EECs we re made to toxicity estimates for endosulfan sulfate.

Acute and chronic risks to terrestrial animal s are estimated based on exposures resulting from applications of endosulfan ( Table 3.23 ) and the appropriate toxicity endpoint from
Table 4.3 . Exposures were not derived for te rrestrial plants, as described in Section 3.4

.

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### 5.1.1 Exposures in the Aquatic Habitat

5.1.1.1 Freshwater Fish and Aquatic-phase Amphibians

Acute risk to freshwater fish and aquatic- phase amphibians, and the potential for direct effects to CRLF and CTS specifically, is based on peak EECs in the standard PRZM/EXAMS pond and the lowest acute toxicity value for freshwater fish. Currently registered agricultural uses of endos ulfan within California are listed in Table 3.1

. Based on freshwater fish toxicity data (LC 50 

### value of 0.1 μg a.i./L for common carp) and modeled aquatic peak EECs for various use scenarios used to represent all of the agricultural uses of endosulfan in CA, all acute RQs for freshwater fish range from 7.2 (eggplant) to 58.8 (lettuce and brussels sprouts) ; therefore, the enti re set of 20 modeled scenarios used to represent all of the agricultural us es of endosulfan in CA, resulted in an exceedance of the Agency’s acute listed species LOC (RQ>0.05)(see Table 5.1 ).

Chronic risk to freshwater fish and aquatic- phase amphibians, and the potential for direct effects to CRLF specifically, is based on 60- day EECs and the lowest chronic toxicity value for freshwater fish. However, in th e case of endosulfan, the fathead minnow acute to chronic ratio (ACR=4.3) was used to estimate a common carp chronic toxicity NOAEC value of 0.023 μg a.i./L because it is th e most acutely sensitive freshwater fish species and no chronic toxicity data are available for it. Based on 60-day EECs for
various use scenarios used to represent all of the agricultural uses of endosulfan in CA, and the estimated NOAEC of 0.023 μg a.i./L, ch ronic RQs for freshwater fish range from 5.7 (eggplant) to 80.6 (lettuce and brussels sprouts. All 20 of the modeled scenarios used to represent all of the agricultural uses of endosulfan in CA resulted in an exceedance of the Agency’s chronic risk LOC (RQ>1) for freshwater fish (see Table 5.1 ).

Based on exceedances of the Agency’s acute listed species LOC (RQ>0.05) for the entire
set of 20 modeled scenarios used to represent all of the agri cultural uses of endosulfan in CA, and exceedances of the Agency’s chronic ri sk LOC (RQ>1) for all 20 of the modeled scenarios, endosulfan does have the potential to directly affect the CRLF and CTS. Additionally, since the acute and chronic RQ s are exceeded, there is a potential for indirect effects to those listed species that rely on freshwater fish (and/or aquatic-phase amphibians) during at least some portion of their life-cycle ( i.e ., CRLF, SFGS, and CTS).

Table 5.1 Acute and Chronic RQs for freshwater fish based on EECs for use categories used to represent a ll endosulfan uses in CA.

Use Category (1) Run
No. Peak EEC (μg/L) 60- day EEC (μg/L) Acute RQ (1) Chronic RQ (1)

Almonds, Hazelnuts & Walnuts 1 3.35 0.62 33.50 26.83

Citrus 1 3.35 0.44 33.50 19.30
Broccoli, Cabbage & Cauliflower 1 4.81 1.76 48.10 76.39
Collards, Kale & Mustard Green 2 1.67 0.50 16.70 21.78
Sweet corn for fresh market only 1 2.88 0.77 28.80 33.65



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### Table 5.1 Acute and Chronic RQs for freshwater fish based on EECs for use categories used to represent a ll endosulfan uses in CA.

Use Category (1) Run
No. Peak EEC (μg/L) 60- day EEC (μg/L) Acute RQ (1) Chronic RQ (1)

Cotton (ground) 2 1.24 0.52 12.40 22.65
Cotton (aerial) 3 1.56 0.59 15.60 25.78

All fruit trees 1 3.40 0.53 34.00 23.13
Lettuce & Brussels Sprouts 1 5.88 1.85 58.80 80.61

Cucurbits 1 1.55 0.61 15.50 26.65
Eggplant 3 0.72 0.13 7.20 5.70

Ornamentals or Shade Trees (Southern Coast) 1 3.43 1.00 34.30 43.65 Ornamentals or Shade Trees (Northern Central coast) 1 Add 4.38 1.13 43.80 49.13

Potato 1 1.89 0.49 18.90 21.39
Potato (Northern Central coast) 1 Add 2.63 0.56 26.30 24.39

Sweet Potato 3 1.18 0.36 11.80 15.57
Beans & Peas (dry) & Pepper 1 2.00 0.51 20.00 22.09
Carrot & Celery 2 1.72 0.54 17.20 23.39
Strawberry 1 3.64 1.11 36.40 48.17

Tomato 1 1.79 0.45 17.90 19.57

(1 ) RQ values in bold indicate exceedenc e of listed species acute LOC (0.05) and chronic LOC (1.0). Acute RQs were calculated based on the peak EEC divided by the LC50 value of 0. 1 μg/L for the most sensitive freshwater fish (common

carp, Cyprinus carpio ). Chronic RQs were based on the 60 day average EEC divided by the estimated chronic NOAEC for common carp of 0.023 μg/L

.



### 5.1.1.2 Freshwater Invertebrates

Acute risk to freshwater invertebrates is based on peak EECs in the standard PRZM/EXAMS pond and the lowest acute toxicity value for freshwater invertebrates.
Based on freshwater inverteb rate toxicity data (EC 50 

### value of 0.6 μg a.i./L for mayflies) and modeled aquatic peak EECs for various us e scenarios used to represent all of the agricultural uses of endosulfa n in CA, all acute RQs for freshwater invertebrates range from 1.20 (eggplant) to 8.02 (broccoli, cabbage , and cauliflower). Th erefore, the entire
set of 20 modeled scenarios used to represent all of the agri cultural uses of endosulfan in CA, resulted in an exceedance of the Agency’s acute listed species LOC (RQ>0.05)(see
Table 5.2 ).

Chronic risk is based on 21-day EECs and the lowest chronic toxicity value for freshwater invertebrates. However, in the case of endosulfan, waterflea acute to chronic ratio (ACR=61.5) was used to estimate a ma yfly chronic toxicity NOAEC value of 0.01 μg a.i./L because it is the most acutely sens itive freshwater invertebrate species and no chronic toxicity data are available for it. Based on 21-day EECs for various use scenarios used to represent all of the agricultural us es of endosulfan in CA, and the estimated NOAEC of 0.01 μg a.i./L, all chronic RQs for freshwater invertebrates range from 23.7 (eggplant) to 260.3 (broccoli, ca bbage, and cauliflower); theref ore, the entire set of 20

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### modeled scenarios used to represent all of the agricultural uses of endosulfan in CA, resulted in an exceedance of the Agency’s chronic risk LOC (RQ>1) for freshwater invertebrates (see Table 5.2 ).

Based on exceedances of the Agency’s acute listed species LOC (RQ>0.05) and chronic risk LOC (RQ>1) for the entire set of 20 mode led scenarios used to represent all of the agricultural uses of endosulfan in CA, there is a potential for direct effects on the CRLF and indirect effects CRLF, SFG S, and CTS, the listed spec ies that rely on freshwater invertebrates during at least so me portion of their life-cycle.

Table 5.2 Acute and Chronic RQs for freshwater in vertebrates based on EECs for use categories used to represent all endosulfan uses in CA.

Use Category (1) Acu Run
No. Peak EEC (μg/L) 21-day EEC (μg/L) te RQ (1) Chronic RQ (1)

Almonds, Hazelnuts & Walnuts 1 3.35 1.03 5.58 102.60

Cit rus 1 3.3 5 0.90 5.58 90.00
Broccoli, Cabbage & Cauliflower 1 4.81 2.60 8.02 260.30
Collards, Kale & Mustard Green 2 1.67 0.78 2.78 77.50
Sweet corn for fresh market only 1 2.88 1.14 4.80 113.70
Cotton (ground) 2 1.24 0.60 2.07 59.60
Cotton (aerial) 3 1.56 0.82 2.60 82.40

All fruit trees 1 3.4 1.01 5.67 101.30
Lettuce & Brussels Sprouts 1 5.88 2.58 9.80 257.50

Cucurbits 1 1.55 0.82 2.58 81.50
Eggplant 3 0.72 0.24 1.20 23.70

Ornamentals or Shade Trees (Southern Coast) 1 3.43 1.36 5.72 135.70 Ornamentals or Shade Trees (Northern Central coast) 1 Add 4.38 1.73 7.30 172.80

Potato 1 1.89 0.77 3.15 77.00
Potato (Northern Central coast) 1 Add 2.63 1.01 4.38 101.10

Sweet Potato 3 1.18 0.62 1.97 62.20
Beans & Peas (dry) & Pepper 1 2 0.85 3.33 85.10
Carrot & Celery 2 1.72 0.74 2.87 73.50
Strawberry 1 3.64 1.71 6.07 171.40

Tomato 1 1.79 0.81 2.98 80.80

(1 ) RQ values in bold indicate exceedenc e of listed species acute LOC (0.05) and chronic LOC (1.0). Acute RQs were calculated based on the peak EEC divided by the LC50 value of 0. 6 μg/L for the most sensitive freshwater invertebrate (mayfly, Atalophlebia australis ). Chronic RQs were based on the 21 day av erage EEC divided by the estimated chronic NOAEC for mayfly of 0.01 μg/L

.



### 130

### 5.1.1.3 Non-vascular Aquatic Plants

Acute risk to aquatic non-vasc ular plants is based on peak EECs in the standard pond and the lowest acute toxicity value. Based on th e only aquatic non-vasc ular plant toxicity datum (EC50 = 428 μg a.i./L for the freshwater green alga Pseudokirchneriella subcapitatum ) and the maximum aquatic peak EEC of all use scenarios representing all of the agricultural uses of endosulfan in CA (5.88 for lettuce and brussels sprouts) all RQs for aquatic non-vascular plants are ≤ 0.014. Since the RQs do not exceed the Agency’s LOC (1) for aquatic non-vascular plan ts, endosulfan is determined to also have
no indirect effects to those liste d species that rely on non-vascul ar aquatic plants during at least some portion of their life-history (i.e., aquatic-phase CRLF, CTS, SFGS, and SMHM).

5.1.1.4 Aquatic Vascular Plants

Toxicity data have not been identified fo r quantitatively estimating risk to vascular aquatic plants, and therefore, RQs cannot be calculated at this time for this taxonomic group. Discussion regarding lines of evidence for the potential for indire ct effects to those listed species that rely on vascular plants dur ing at least some portion of their life-history (i.e., aquatic-phase CRLF, CTS, SFGS, and SMHM) can be found in the “Risk Description” portion of the chapter ( Section 5.2 ).

5.1.2 Exposures in the Terrestrial Habitat

5.1.2.1 Birds (surrogate for Reptiles and Terrestrial-phase amphibians)

As previously discussed in Section 3.3 , potential direct effects to terrestrial species are based on foliar applications of endosulfan. Potential direct acute effects are derived by considering dose- and dietar y-based EECs modeled in T-RE X for a small bird (20 g) consuming a variety of dietary items ( Table 3.23 ) and acute oral and subacute dietary toxicity endpoints for avian species. Based on the most sensitive bird acute data (LD50=28 mg/kg b.w. for the mallard duck) ad justed for differences in body weight by T-REX (LD50=14.54 mg/kg b.w.), and the modeled acute dose-based EECs for various use scenarios and diet categor ies, all RQs for small birds ranged from 0.13 (Eggplant, Granivores) to 47 (three differe nt use categories for short gr ass diet). All 100 acute dosebased RQs for uses of endosulfan in CA resu lted in an exceedence of the Agency’s acute listed species risk LOC (RQ>0.1) for birds (see Table 5.3 ). Acute dietary-based EECs and the most sensitive bird dietary toxicity value (805 mg/kg diet for bobwhite quail) resulted in RQs that ranged from 0.01 (4 different use categories for fruit/pods/seeds/large insects dietary category) to 0.75 (3 us e categories for short grass). Only 57 of the 80 acute dietary-based RQs ex ceeded the Agency’s acute listed species risk LOC (>0.1) for birds ( Table 5.3 ).

Potential direct chronic effects to terrestri al birds (and reptiles and terrestrial-phase amphibians) are derived by considering di etary-based EECs modeled in T-REX for a small bird (20 g) consuming a variety of di etary items. Chronic effects are estimated

131

### using the lowest available chronic dietary t oxicity data for birds (NOEC= 30 mg/kg diet. for mallard duck). Chroni c dietary-based RQs ranged from 0.25 (eggplant for fruit/pods/seeds/large insects) to 20 (3 different use cate gories for short grass). Sixtythree of the 80 chronic dietary-based RQs ex ceeded the Agency’s chronic risk LOC (>1) for birds ( Table 5.3 ).

Based on exceedences of the Agency’s acute risk LOC (RQ>0.1) and chronic risk LOC (RQ>1) endosulfan does have the potential to di rectly effect reptiles and terrestrial-phase amphibians (i.e., CRLF, CTS and SFGS) during at least some portion of their life-history. In addition, endosulfan also has the potentia l to indirectly affect the CRLF, SFGS, SMHM and SJKF since they potentially rely on birds, reptiles or terrestrial-phase amphibians during some portion of their life-history.

Table 5.3 Summary of the acute and chro nic dose- and dietary-based RQs for birds (20 g) estimated based on the maxi mum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run
No. Dietary Category Acute DoseBased (1) Sub AcuteDietaryBased (1) ChronicDietaryBased (1)

Short Grass 37.60 0.60 16.00

Tall Grass 17.23 0.27 7.33

Broadleaf Plants/ Small
Insects 21.15 0.34 9.00

Fruits/Pods/ Seeds/ Large
Insects 2.35 0.04 1.00 Almonds, hazelnut &
walnut 1

Granivore 0.52

Short Grass 47.00 0.75 20.00

Tall Grass 21.54 0.34 9.17

Broadleaf Plants/ Small
Insects 26.44 0.42 11.25

Fruits/Pods/ Seeds/ Large
Insects 2.94 0.05 1.25 Citrus 1

Granivore 0.65

Short Grass 24.39 0.39 10.38

Tall Grass 11.18 0.18 4.76

Broadleaf Plants/ Small
Insects 13.72 0.22 5.84

Fruits/Pods/ Seeds/ Large
Insects 1.52 0.02 0.65 Broccoli, cabbage, Chinese cabbage, cauliflower, kohlrabi 1

Granivore 0.34

Short Grass 14.10 0.22 6.00

Tall Grass 6.46 0.10 2.75

Broadleaf Plants/ Small
Insects 7.93 0.13 3.38

Fruits/Pods/ Seeds/ Large
Insects 0.88 0.01 0.38 Kale, Collards & Mustard Green 2

Granivore 0.20

Short Grass 28.20 0.45 12.00

Tall Grass 12.93 0.20 5.50 Sweet corn 1

Broadleaf Plants/ Small
Insects 15.86 0.25 6.75



### 132

### Table 5.3 Summary of the acute and chro nic dose- and dietary-based RQs for birds (20 g) estimated based on the maxi mum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run
No. Dietary Category Acute DoseBased (1) Sub AcuteDietaryBased (1) ChronicDietaryBased (1)

Fruits/Pods/ Seeds/ Large
Insects 1.76 0.03 0.75

Granivore 0.39

Short Grass 18.80 0.30 8.00

Tall Grass 8.62 0.14 3.67

Broadleaf Plants/ Small
Insects 10.58 0.17 4.50

Fruits/Pods/ Seeds/ Large
Insects 1.18 0.02 0.50 Cotton (ground) 1

Granivore 0.26

Short Grass 18.29 0.29 7.78

Tall Grass 8.38 0.13 3.57

Broadleaf Plants/ Small
Insects 10.29 0.16 4.38

Fruits/Pods/ Seeds/ Large
Insects 1.14 0.02 0.49 Cotton (Areal) 3

Granivore 0.25

Short Grass 47.00 0.75 20.00

Tall Grass 21.54 0.34 9.17

Broadleaf Plants/ Small
Insects 26.44 0.42 11.25

Fruits/Pods/ Seeds/ Large
Insects 2.94 0.05 1.25 Apples 1

Granivore 0.65

Short Grass 47.00 0.75 20.00

Tall Grass 21.54 0.34 9.17

Broadleaf Plants/ Small
Insects 26.44 0.42 11.25

Fruits/Pods/ Seeds/ Large
Insects 2.94 0.05 1.25 Apricot, nectarine, peach, cherry, pear, plum & prune 1

Granivore 0.65

Short Grass 26.71 0.42 11.36

Tall Grass 12.24 0.19 5.21

Broadleaf Plants/ Small
Insects 15.02 0.24 6.39

Fruits/Pods/ Seeds/ Large
Insects 1.67 0.03 0.71 Lettuce & Brussels sprouts 1

Granivore 0.37

Short Grass 24.39 0.39 10.38

Tall Grass 11.18 0.18 4.76

Broadleaf Plants/ Small
Insects 13.72 0.22 5.84

Fruits/Pods/ Seeds/ Large
Insects 1.52 0.02 0.65 Cucumber, melons, pumpkin & squash 1

Granivore 0.34

Short Grass 9.40 0.15 4.00 Eggplant 3

Tall Grass 4.31 0.07 1.83



### 133

### Table 5.3 Summary of the acute and chro nic dose- and dietary-based RQs for birds (20 g) estimated based on the maxi mum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run
No. Dietary Category Acute DoseBased (1) Sub AcuteDietaryBased (1) ChronicDietaryBased (1)

Broadleaf Plants/ Small
Insects 5.29 0.08 2.25

Fruits/Pods/ Seeds/ Large
Insects 0.59 0.01 0.25

Granivore 0.13

Short Grass 11.42 0.18 4.86

Tall Grass 5.23 0.08 2.23

Broadleaf Plants/ Small
Insects 6.42 0.10 2.73

Fruits/Pods/ Seeds/ Large
Insects 0.71 0.01 0.30 Ornamentals & shade

trees 1

Granivore 0.16

Short Grass 26.71 0.42 11.36

Tall Grass 12.24 0.19 5.21

1 Broadleaf Plants/ Small
Insects 15.02 0.24 6.39

Fruits/Pods/ Seeds/ Large
Insects 1.67 0.03 0.71 Potato

Granivore 0.37

Short Grass 15.01 0.24 6.39

Tall Grass 6.88 0.11 2.93

3 Broadleaf Plants/ Small
Insects 8.45 0.13 3.59

Fruits/Pods/ Seeds/ Large
Insects 0.94 0.01 0.40 Sweet potato

Granivore 0.21

Short Grass 26.71 0.42 11.36

Tall Grass 12.24 0.19 5.21

1 Broadleaf Plants/ Small
Insects 15.02 0.24 6.39

Fruits/Pods/ Seeds/ Large
Insects 1.67 0.03 0.71 Dry beans (except Lima), peas & pepper

Granivore 0.37

Short Grass 18.80 0.30 8.00

Tall Grass 8.62 0.14 3.67

2 Broadleaf Plants/ Small
Insects 10.58 0.17 4.50

Fruits/Pods/ Seeds/ Large
Insects 1.18 0.02 0.50 Carrot

Granivore 0.26

Short Grass 18.80 0.30 8.00

Tall Grass 8.62 0.14 3.67

2 Broadleaf Plants/ Small
Insects 10.58 0.17 4.50

Fruits/Pods/ Seeds/ Large
Insects 1.18 0.02 0.50 Celery

Granivore 0.26



### 134

### Table 5.3 Summary of the acute and chro nic dose- and dietary-based RQs for birds (20 g) estimated based on the maxi mum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run
No. Dietary Category Acute DoseBased (1) Sub AcuteDietaryBased (1) ChronicDietaryBased (1)

Short Grass 20.20 0.32 8.59

Tall Grass 9.26 0.15 3.94

2 Broadleaf Plants/ Small
Insects 11.36 0.18 4.83

Fruits/Pods/ Seeds/ Large
Insects 1.26 0.02 0.54 Strawberry

Granivore 0.28

Short Grass 24.39 0.39 10.38

Tall Grass 11.18 0.18 4.76

1 Broadleaf Plants/ Small
Insects 13.72 0.22 5.84

Fruits/Pods/ Seeds/ Large
Insects 1.52 0.02 0.65 Tomato

Granivore 0.34

(1 ) RQ values in bold indicate exceedenc e of acute LOC (0.1) and chronic LOC (1.0). Acute dose-based RQs were based on the dose-based EECs divided by the adjusted LD50 for a 20 g bird (14.54 mg/kg b.w.). Acute dietary-based RQs were based on the dietary EECs divided by the avi an acute dietary LC50 (805 mg/kg diet). Chronic RQs based on the dietary EECs divided by th e avian NOEC (30 mg/kg diet).



### 5.1.2.2 Mammals

Potential risks to mammals are derived using T-REX, acute and chronic rat toxicity data, and a two body-size and dietary categories. Pote ntial direct acute e ffects specifically to the salt marsh harvest mouse (SMHM) are derived by consideri ng dose- and dietarybased EECs modeled in T-REX for a small mammal (15 g) consuming a variety of dietary items ( Table 5.4 ) and acute oral and subacute di etary toxicity endpoints for rats. Potential direct acute effects specifically to the San Joaquin kit fox (SJKF) are derived by considering dose- and dietar y-based EECs modeled in T-RE X for a large mammal (1,000 g) consuming a variety of dietary items ( Table 5.4 ) and acute oral and subacute dietary toxicity endpoints for rats. Based on the rat acute data (L D50=10 kg/kg b.w.) adjusted for differences in body weight for a 15 g sm all mammal by T-REX (LD50=21.98) and the
modeled dose-based EECs for various use scenar ios and diet categories, all RQs for small mammals ranged from 0.07 to 26.03 with 96 of the 100 modeled scenarios exceeding the Agency’s acute listed species risk LOC ( 0.1). Based on the adjusted LD50 for a large mammal (LD50=7.69 mg/kg b.w.), and the modele d EECs, the acute dose-based RQs for large mammals ranged from 0.03 to 11.92, with 84 of the 100 modeled scenarios exceeding the Agency’s LOC (0.1).

Potential chronic risks to mammals are de rived using a calculated NOAEL (0.75 mg/kg b.w.) from T-REX which is based on the ch ronic dietary NOAEC of 15 mg/kg diet for rats. This calculated toxicity value was furt her adjusted in T-REX based on the size class of the mammals (1.65 mg/kg b.w for 15 g and 0.58 mg/kg b.w. for 1000 g). These

135

### adjusted values, coupled with the dose-based EECs, resulted in RQs that range from 0.96 to 347.04 for the small mammal (15 g) and from 0.44 to 158.9 for the large mammal (1000 g) (see Table 5.4 ). Ninety-nine of the 100 RQs fo r the small mammal, and 91 of 100 RQs for the large mammal exceeded the Agency’s chronic risk LOC (RQ>1) formammals. Additional chronic risks to mammals are derived using the chronic dietarybased EECs and the dietary chronic value for ra ts (15 mg/kg diet). These chronic dietarybased RQs ranged from 0.50 to 40, with 72 of the 100 modeled scenarios resulting in RQs exceeding the Agency’s chronic risk LOC (RQ>1)

Based on exceedences of the Agency’s acute risk LOC (RQ>0.1) and chronic risk LOC (RQ>1) endosulfan has the potential to directly affect the SMHM and SJKF. Additionally, since the acute and chronic RQ s are exceeded, there is a potential for indirect effects to those listed species that rely on mammals during at least some portion of their life-cycle ( i.e ., CRLF, SFGS, SMHS, and SJKF).

Table 5.4 Summary of the acute and chro nic dose- and dietary-based RQs for
mammals estimated based on the maximum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run Dietary Category Acute DoseBased (1) Chronic DoseBased (1) Chronic Dietary (1)

-

No. 15 g 1000 g 15 g 1000 g Based

Short Grass 20.82 9.53 277.63 127.12 32.00

Tall Grass 9.54 4.37 127.25 58.26 14.67

Broadleaf Plants/ Small Insects 11.71 5.36 156.17 71.51 18.00

Fruits/Pods/ Seeds/ Large Insects 1.30 0.60 17.35 7.95 2.00 Almonds,
hazelnut & walnut 1

Granivore 0.29 0.13 3.86 1.77

Short Grass 26.03 11.92 347.04 158.90 40.00

Tall Grass 11.93 5.46 159.06 72.83 18.33

Broadleaf Plants/ Small Insects 14.64 6.70 195.21 89.38 22.50 Fruits/Pods/ Seeds/ Large Insects 1.63 0.74 21.69 9.93 2.50 Citrus 1

Granivore 0.36 0.17 4.82 2.21

Short Grass 13.51 6.18 180.09 82.46 20.76

Tall Grass 6.19 2.83 82.54 37.79 9.51

Broadleaf Plants/ Small Insects 7.60 3.48 101.30 46.38 11.68 Fruits/Pods/ Seeds/ Large Insects 0.84 0.39 11.26 5.15 1.30 Broccoli, cabbage, Chinese cabbage, cauliflower,
kohlrabi 1

Granivore 0.19 0.09 2.50 1.15

Short Grass 7.81 3.58 104.11 47.67 12.00

Tall Grass 3.58 1.64 47.72 21.85 5.50

Broadleaf Plants/ Small Insects 4.39 2.01 58.56 26.82 6.75 Fruits/Pods/ Seeds/ Large Insects 0.49 0.22 6.51 2.98 0.75 Kale, Collards & Mustard Green 2

Granivore 0.11 0.05 1.45 0.66

Short Grass 15.62 7.15 208.22 95.34 24.00

Tall Grass 7.16 3.28 95.44 43.70 11.00

Broadleaf Plants/ Small Insects 8.78 4.02 117.13 53.63 13.50 Fruits/Pods/ Seeds/ Large Insects 0.98 0.45 13.01 5.96 1.50 Sweet corn 1

Granivore 0.22 0.10 2.89 1.32

Short Grass 10.41 4.77 138.82 63.56 16.00

Tall Grass 4.77 2.18 63.62 29.13 7.33

Broadleaf Plants/ Small Insects 5.86 2.68 78.08 35.75 9.00 Cotton (ground) 1

Fruits/Pods/ Seeds/ Large Insects 0.65 0.30 8.68 3.97 1.00



### 136

### Table 5.4 Summary of the acute and chro nic dose- and dietary-based RQs for
mammals estimated based on the maximum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run Dietary Category Acute DoseBased (1) Chronic DoseBased (1) Chronic Dietary (1)

-

No. 15 g 1000 g 15 g 1000 g Based

Granivore 0.14 0.07 1.93 0.88

Short Grass 10.13 4.64 135.07 61.84 15.57

Tall Grass 4.64 2.13 61.90 28.35 7.14

Broadleaf Plants/ Small Insects 5.70 2.61 75.97 34.79 8.76 Fruits/Pods/ Seeds/ Large Insects 0.63 0.29 8.44 3.87 0.97 Cotton (Areal) 3

Granivore 0.14 0.06 1.88 0.86

Short Grass 26.03 11.92 347.04 158.90 40.00

Tall Grass 11.93 5.46 159.06 72.83 18.33

Broadleaf Plants/ Small Insects 14.64 6.70 195.21 89.38 22.50 Fruits/Pods/ Seeds/ Large Insects 1.63 0.74 21.69 9.93 2.50 Apples 1

Granivore 0.36 0.17 4.82 2.21

Short Grass 26.03 11.92 347.04 158.90 40.00

Tall Grass 11.93 5.46 159.06 72.83 18.33

Broadleaf Plants/ Small Insects 14.64 6.70 195.21 89.38 22.50 Fruits/Pods/ Seeds/ Large Insects 1.63 0.74 21.69 9.93 2.50 Apricot, nectarine, peach, cherry, pear, plum &

prune 1

Granivore 0.36 0.17 4.82 2.21

Short Grass 14.79 6.77 197.18 90.29 22.73

Tall Grass 6.78 3.10 90.38 41.38 10.42

Broadleaf Plants/ Small Insects 8.32 3.81 110.91 50.79 12.78 Fruits/Pods/ Seeds/ Large Insects 0.92 0.42 12.32 5.64 1.42 Lettuce & Brussels sprouts 1

Granivore 0.21 0.09 2.74 1.25

Short Grass 13.51 6.18 180.09 82.46 20.76

Tall Grass 6.19 2.83 82.54 37.79 9.51

Broadleaf Plants/ Small Insects 7.60 3.48 101.30 46.38 11.68 Fruits/Pods/ Seeds/ Large Insects 0.84 0.39 11.26 5.15 1.30 Cucumber, melons, pumpkin & squash 1

Granivore 0.19 0.09 2.50 1.15

Short Grass 5.21 2.38 69.41 31.78 8.00

Tall Grass 2.39 1.09 31.81 14.57 3.67

Broadleaf Plants/ Small Insects 2.93 1.34 39.04 17.88 4.50 Fruits/Pods/ Seeds/ Large Insects 0.33 0.15 4.34 1.99 0.50 Eggplant 3

Granivore 0.07 0.03 0.96 0.44

Short Grass 6.32 2.90 84.31 38.60 9.72

Tall Grass 2.90 1.33 38.64 17.69 4.45

Broadleaf Plants/ Small Insects 3.56 1.63 47.42 21.71 5.47 Fruits/Pods/ Seeds/ Large Insects 0.40 0.18 5.27 2.41 0.61 Ornamentals &
shade trees 1

Granivore 0.09 0.04 1.17 0.54

Short Grass 14.79 6.77 197.18 90.29 22.73

Tall Grass 6.78 3.10 90.38 41.38 10.42

Broadleaf Plants/ Small Insects 8.32 3.81 110.91 50.79 12.78 Fruits/Pods/ Seeds/ Large Insects 0.92 0.42 12.32 5.64 1.42 Potato 1

Granivore 0.21 0.09 2.74 1.25

Short Grass 8.31 3.81 110.86 50.76 12.78

Tall Grass 3.81 1.74 50.81 23.27 5.86

Broadleaf Plants/ Small Insects 4.68 2.14 62.36 28.55 7.19 Fruits/Pods/ Seeds/ Large Insects 0.52 0.24 6.93 3.17 0.80 Sweet potato 3

Granivore 0.12 0.05 1.54 0.71



### 137

### Table 5.4 Summary of the acute and chro nic dose- and dietary-based RQs for
mammals estimated based on the maximum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run Dietary Category Acute DoseBased (1) Chronic DoseBased (1) Chronic Dietary (1)

-

No. 15 g 1000 g 15 g 1000 g Based

Short Grass 14.79 6.77 197.18 90.29 22.73

Tall Grass 6.78 3.10 90.38 41.38 10.42

Broadleaf Plants/ Small Insects 8.32 3.81 110.91 50.79 12.78 Fruits/Pods/ Seeds/ Large Insects 0.92 0.42 12.32 5.64 1.42 Dry beans (except Lima), peas & pepper 1

Granivore 0.21 0.09 2.74 1.25

Short Grass 10.41 4.77 138.82 63.56 16.00

Tall Grass 4.77 2.18 63.62 29.13 7.33

Broadleaf Plants/ Small Insects 5.86 2.68 78.08 35.75 9.00 Fruits/Pods/ Seeds/ Large Insects 0.65 0.30 8.68 3.97 1.00 Carrot 2

Granivore 0.14 0.07 1.93 0.88

Short Grass 10.41 4.77 138.82 63.56 16.00

Tall Grass 4.77 2.18 63.62 29.13 7.33

Broadleaf Plants/ Small Insects 5.86 2.68 78.08 35.75 9.00 Fruits/Pods/ Seeds/ Large Insects 0.65 0.30 8.68 3.97 1.00 Celery 2

Granivore 0.14 0.07 1.93 0.88

Short Grass 11.19 5.12 149.13 68.29 17.19

Tall Grass 5.13 2.35 68.35 31.30 7.88

Broadleaf Plants/ Small Insects 6.29 2.88 83.89 38.41 9.67 Fruits/Pods/ Seeds/ Large Insects 0.70 0.32 9.32 4.27 1.07 Strawberry 2

Granivore 0.16 0.07 2.07 0.95

Short Grass 13.51 6.18 180.09 82.46 20.76

Tall Grass 6.19 2.83 82.54 37.79 9.51

Broadleaf Plants/ Small Insects 7.60 3.48 101.30 46.38 11.68 Fruits/Pods/ Seeds/ Large Insects 0.84 0.39 11.26 5.15 1.30 Tomato 1

Granivore 0.19 0.09 2.50 1.15

(1 ) RQ values in bold indicate exceedenc e of listed species acute LOC (0.1) a nd chronic LOC (1.0). Acute dose-based RQs were based on dose-based EECs divided by adjusted rat LD 50s (21.98 mg/kg b.w for 15 g and 7.69 mg/kg b.w. for 1000g). Chronic dose-based RQs were based on dose-based EEC s divided by adjusted rat NOAECs (1.65 mg/kg b.w. for 15 g and 0.58 mg/kg b.w. for 1000g). Chronic dietary- based RQs were based on dietary EECs divided by the chronic dietary NOAEC for rats (15 mg/kg diet).



### 5.1.2.3 Terrestrial Invertebrates

Potential risks to terrestrial invertebrates resulting from foliar spray applications of endosulfan are derived using T-REX, and the mo st sensitive toxicity data available for
terrestrial invertebrate s. In the case of endosulfan, the beet web worm was used as a surrogate for evaluating risks of endosulfan to terrestrial invertebrates. The toxicity value
for terrestrial invertebrates is the lowest available acute contact LD50 (0.15 μg a.i./g) EECs in ppm calculated by T-REX for small a nd large insects are divided by the above toxicity value for terrestrial invertebrates. Larvae for both the Bay checkerspot butterfly and the Valley elderberry longhorn beetle ar e considered ‘small insects’ in this assessment, while the adults of these species are considered ‘large insects’. Based on the EECs and the above contact acute value, all 20 use category RQs for small insects ranged from 450 to 2250, and those for large insects ranged from 50 to 250 ( Table 5.5 ). All 20

138

### use category RQs for both size classes exceeded the Agency’s interim LOC for listed terrestrial invertebrates (RQ>0.05). Based on the exceedences of the Agency’s interim
LOC for listed terrestrial invert ebrates, endosulfan use in CA does have the potential to directly adversely affect the BCB and the VELB ( Table 5.5 ). Additionally, since the RQs are exceeded, there is a potential for indirect effects to thos e listed species that rely on terrestrial invertebrates during at leas t some portion of their life-cycle ( i.e ., CRLF, SFGS, CTS, SMHM, and SJKF.

Table 5.5 Summary of the acute and chronic dose- and di etary-based RQs terrestrial insects estimated based on the maximum endosulfan foliar spray applications using T-REX version 1.4.1.

Use Category Run No. Dietary Category Small insects (1) Large insects (1)

Broadleaf Plants/ Small Insects 1800 Almonds, hazelnut & walnut 1 Fruits/Pods/ Seeds/ Large Insects 200

Broadleaf Plants/ Small Insects 2250 Citrus 1 Fruits/Pods/ Seeds/ Large Insects 250

Broadleaf Plants/ Small Insects 1168 Broccoli, cabbage, Chinese cabbage, cauliflower, kohlrabi 1 Fruits/Pods/ Seeds/ Large Insects 130

Broadleaf Plants/ Small Insects 675 Kale, Collards & Mustard Green 2 Fruits/Pods/ Seeds/ Large Insects 75

Broadleaf Plants/ Small Insects 1350 Sweet corn 1 Fruits/Pods/ Seeds/ Large Insects 150

Broadleaf Plants/ Small Insects 900 Cotton (ground) 1 Fruits/Pods/ Seeds/ Large Insects 100

Broadleaf Plants/ Small Insects 876 Cotton (Areal) 3 Fruits/Pods/ Seeds/ Large Insects 97

Broadleaf Plants/ Small Insects 2250 Apples 1 Fruits/Pods/ Seeds/ Large Insects 250

Broadleaf Plants/ Small Insects 2250 Apricot, nectarine, peach, cherry, pear, plum & prune 1 Fruits/Pods/ Seeds/ Large Insects 250

Broadleaf Plants/ Small Insects 1278 Lettuce & Brussels sprouts 1 Fruits/Pods/ Seeds/ Large Insects 142

Broadleaf Plants/ Small Insects 1168 Cucumber, melons, pumpkin & squash 1 Fruits/Pods/ Seeds/ Large Insects 130

Broadleaf Plants/ Small Insects 450 Eggplant 3 Fruits/Pods/ Seeds/ Large Insects 50

Broadleaf Plants/ Small Insects 547 Ornamentals & shade trees 1 Fruits/Pods/ Seeds/ Large Insects 61

Broadleaf Plants/ Small Insects 1278 Potato 1 Fruits/Pods/ Seeds/ Large Insects 142

Broadleaf Plants/ Small Insects 719 Sweet potato 3 Fruits/Pods/ Seeds/ Large Insects 80

Broadleaf Plants/ Small Insects 1278 Dry beans (except Lima), peas &

pepper 1 Fruits/Pods/ Seeds/ Large Insects 142

Broadleaf Plants/ Small Insects 900 Carrot 2 Fruits/Pods/ Seeds/ Large Insects 100

Broadleaf Plants/ Small Insects 900 Celery 2 Fruits/Pods/ Seeds/ Large Insects 100

Broadleaf Plants/ Small Insects 967 Strawberry 2 Fruits/Pods/ Seeds/ Large Insects 107

Broadleaf Plants/ Small Insects 1168 Tomato 1 Fruits/Pods/ Seeds/ Large Insects 130



### 139Table 5.5 Summary of the acute and chronic dose- and di etary-based RQs terrestrial insects estimated based on the maximum endosulfan foliar spray applications using T-REX version 1.4.1.

Small insects (1) Large insects (1) Use Category Run No. Dietary Category

(2 ) RQ values in bold indicate exceedence of A gency’s interim LOC for listed terrestrial invertebrates (0.05). Terrestrial insect R Qs were based on diet category EECs for small and large insects divided by the contact acute value for beet webworm, Pyrausta sticticalis (LD50=0.15 μg/g).



### 5.1.2.4 Terrestrial Plants

Generally, for indirect effects, potential e ffects on terrestrial vegetation are assessed using RQs from terrestrial plant seedling em ergence and vegetative vigor EC25 data as a screen. However, such toxicity data have not been identified for quantitatively estimating risk to terrestrial pl ants (as described in Section 4.2.4 ) as a result of endosulfan use; therefore, RQs cannot be calculated at this time for this taxonomic group. Discussion regarding lines of evidence for the potential for indirect effects to those listed species that rely on terrestrial plants during at least some portion of their life-his tory (i.e., terrestrialphase CRLF, SFGS, CTS, BCB, VELB, SMHM and SJKF) can be found in the ”Risk Description” portion of the chapter ( Section 5.2 ).

5.1.3 Primary Constituent Elements of Designated Critical Habitat

For endosulfan use, the assessment endpoints fo r designated critical habitat PCEs involve the same endpoints as those being assessed relati ve to the potential fo r direct and indirect effects to the listed species assessed here. Ther efore, the effects determinations for direct
and indirect effects are used as the basis of the effects determination for designated
critical habitat.

5.1.4 Spatial Extent of Potential Effects

In order to determine the spatial extent of e ffects on terrestrial and a quatic habitats due to endosulfan exposures through spray drift, it is necessary to estim ate the distance that spray applications can drift from the treated area and still be present at concentrations that exceed levels of concern. An analysis of spray drift distances was completed using all available tools, including AgDrift, AGDISP and the Gaussian extension to AGDISP.

5.1.4.1 Spray Drift

Spray drift analysis determines the additional distance from the treated area where listed species LOCs are exceeded as a result of sp ray drift. This distance is based on the taxonomic group that yields the largest RQ to LOC ratio. Both te rrestrial and aquatic taxonomic groups are considered in this analysis.

For endosulfan, the results of the screening- level assessment indicat e that the required
values are one value for LOC= 0.05 and two values for RQ (2,250 for apples and 1,350 for sweet corn). Using these values, AgDr ift and AGDISP were not able to estimate needed buffer distance, therefore the Gau ssian extension to AGDISP was used. Buffer distances were determined for two crops, an orchard and a field crop with varying

140

### application parameters as described in details in Appendix G . Spray drift results range from 12,266 to 12,775 feet for orchards and 3,383 to 11,279 feet for field crops.

5.1.4.2 Downstream Dilution Analysis

Down-stream dilution analysis is necessary to define the full extent of the effects area. This is because effects area may be larger than the initial area of con cern or “footprint” of potential uses. This analysis determines downstream extent of exposure in streams and rivers where the EEC could potentially be a bove levels that would exceed the highest RQ to LOC ratio. Based on all aquatic RQs, the greatest RQ to LOC ratio for all aquatic organisms (plants and animals) are determined for the two major use patterns ( Table
5.6 ).

Table 5.6 Summary of the highest RQ to LOC ratios fo r the two GIS use categories for endosulfan

Category* Use Pattern Species RQ LOC Cultivated Crops Lettuce/Brussels Sprouts 58.8 Orchards/Vineyards Pear Common Carp 33.5 0.05

* Two GIS mapping categories.



### The ratios in Table 5.6 would be used to determine the downstream extent of the effects area. Results of this analysis for endos ulfan suggest that th e maximum distance downstream is 285 km for cultivated crops a nd 120 km for orchards. Therefore, exposure and possible effects on most sensitive a quatic species may extend to 120 to 285 km beyond the initial area of concern shown in Figure 2.6

.

5.1.4.3 Overlap between CRLF, CTS, SF GS, BCB, VELB, SMHM, and SJKF habitat and Spatial Extent of Potential Effects

Table 5.7 shows a summary of recent usage data in counties where the CRLF and the San Francisco Bay species occur.

Table 5.7 Summary of average endosu lfan usage data and occurrence of th e CRLF and the San Francisco Bay species at the county level

Average Usage (2005-2006) CRLF and San Francisco Bay Species 1

County lbs % Rank 2 CRLF SFGS SMHM BCB VELB SJKF CTS

Alameda No Use Reported ****

Colusa 250.96 0.29%

Contra Costa No Use Reported

Fresno 44,937.84 51% 1

Glenn 4.16 0.00% Imperial 7,004.91 8% 3

Kern 2,584.47 3% 5 Kings 19,648.25 22% 2



### 141Table 5.7 Summary of average endosu lfan usage data and occurrence of th e CRLF and the San Francisco Bay species at the county level

CRLF and San Francisco Bay Species 1 Average Usage (2005-2006) County lbs Rank 2 % CRLF SFGS SMHM BCB VELB SJKF CTS

Los Angeles 40.13 0.05%

Madera 468.2 0.53%

Marin No Use Reported

Merced 230.2 0.26% Monterey 396.45 0.45% Napa 4.56 0.01%

Placer 9.09 0.01%

Riverside 2,926.87 3% 4

San Benito 646.58 0.74% 11

San Bernardino No Use Reported

San Francisco No Use Reported San Joaquin 137.55 0.16% San Luis Obispo No Use Reported

San Mateo 0.25 0.00%

Santa Barbara 1 0.00%

Santa Clara 173.33 0.20%

Santa Cruz No Use Reported Siskiyou 2,063.91 2% 7

Solano 885.72 1% 10

Sonoma 55.75 0.06%

Stanislaus No Use Reported

Sutter 1,027.73 1% 9

Tulare 1,879.55 2% 8

Ventura 63.38 0.07%

Yolo 2,151.40 2% 6

Total 87,592.24 100% Species occurrence= Yes

1 California red-legged frog (Rana aurora draytonii ) (CRLF), San Francisco Garter Snake ( Thamnophis sirtalis

tetrataenia ) (SFGS), Salt Marsh Harvest Mouse ( Reithrodontomys raviventris ) (SMHM), Bay Checkerspot Butterfly ( Euphydryas editha bayensis ) (BCB), Valley Elderberry Longhorn Beetle ( Desmocerus californicus dimorphus ) (VELB), San Joaquin Kit Fox ( Vulpes macrotis mutica ) (SJKF ) , and California Tiger Salamander ( Ambystoma californiense ) (CTS).
2 Top 11 counties with usage over 500 lb/county



### In contrast, possible overlap of the species occurrence and potential usage are shown in maps included in Appendix E . Co-occurrence data are summarized in Table 5.8

.

Table 5.8 Extent and location of ov erlap between areas of species occurrence and areas of potential endosulfan usage

Species Extent of possible overlap/Counties of Occurrence

CRLF Low with high acreage of both cultivated crops and orchards in the following Counties: Santa



### 142Clara, Santa Barbara, Alameda, Contra Costa, Ventura, San Benito, Merced, Stanislaus, and San Joaquin

SFGS High with low acreage of cultivated crops only in San Mateo County

SMHM Very low with low acreage of cultivated crops in only in Sonoma County

BCB High with low acreage of cultivated crops and orchards only in Santa Clara County

VELB Medium with cultivated crops and orchards in only Solano County

SJKF Low with high acreage of mainly cultivated crops in the western edge of the central valley counties including: Contra Costa, Alameda, San Bento, Monterey, San Joaquin, Stanislaus, Merced, Kings, Fresno and Kern.

CTS Low with high acreage of mainly orchards in the eastern edge of the central valley counties including: : Sacramento, Santa Clara, Stanislaus, Alameda, Contra Costa, Merced, Madera, and

Fresno



### Data show the species occurrence may overl ap with potential e ndosulfan usage although the extent appears to be generally limited because it is either low or occurs on limited acreage. It is important to note howev er, the following contradicting factors:

(1) Drift is expected to cause extension of the initial area of concern for most sensitive terrestrial species by 2.1 miles for cultivated crops to 2.4 miles for
orchards. ( 2) Downstream dilution is expected to cause extension of the initial area of concern for most sensitive aquatic species by 75 m iles (120 km) for cultivated crops to 177 miles (285 km) for orchards. (3) Areas associated with endosulfan usage are expected to be much smaller than those mapped because endosulfan is not us ed on all cultivated crops or on all
orchards and vines.

The first two factors would tend to increase the extent of the area affected while the third factor would reduce the possibili ty of the overlap to occur.

5.2 Risk Description

The risk description synthesizes overall conc lusions 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 advers ely affect”) for the assessed species and the potential for effects to their designated critical habitat.

If the RQs presented in the Risk Estimation ( Section 5.1 ) show no direct or indirect effects for the assessed species, and no effects to PCEs of the designa ted critical habitat, a “no effect” determination is made, based on the use of endosulfan within the action area. However, if LOCs for direct or indir ect effect are exceeded or there may be effects to the PCEs of the critical habitat, the Agency concludes a preliminary “may affect” determination for the FIFRA regulat ory action regarding endosulfan

Based on exceedances of LOCs, a potential to cause adverse effects to CRLF, SFGS, SMHM, BCB, VELB, SJKF and CTS and potential to cause effects designated critical habitat (CRLF, BCB, VELB and CTS) has b een identified. The Agency concludes a

143

### preliminary “may affect” determination for the CRLF, SFGS, SMHM, BCB, VELB, SJKF and CTS based on the currently labeled uses of endosulfan. A summary of the risk estimation results are provided in Table 5.9 for direct and indirect effects to the listed species assessed here and in Table 5.10 for the PCEs of their desi gnated critical habitat.

Table 5.9 Risk Estimation Summary for e ndosulfan - Direct and Indirect Effects

Taxa (1) LOC Exceedances

(Y/N) Description of Results of Risk Estimation Assessed Species
Potentially Affected Direct Effects :

Aquatic-phase CRLF,CTS Freshwater Fish and Aquatic-phase Amphibians (Y) Acute RQs range from 7.2 to 58.8; exceeding the Agency’s acute listed species LOC (0.05) in all 20 crop scenarios.

Chronic RQs range from 5.7 to 80.6; exceeding the Agency’s chronic species LOC (1.0) in all 20 crop scenarios. Indirect Effects:

Aquatic-phase CRLF, SFGS, CTS

Freshwater
Invertebrates (Y) Acute RQs range from 1.2 to 9.8 for freshwater invertebrates; exceeding the Agency’s acute liste d species LOC (0.05) in all 20 crop scenarios.

Chronic RQs range from 23.7 to 260; exceeding the Agency’s chronic species LOC (1.0) in all 20 crop scenarios. Indirect Effects:

Aquatic-phase CRLF, SFGS, CTS

Vascular Aquatic
Plants (N; however

effects cannot be quantified) There are no acceptable vascular aquatic plant data available Indirect Effects:

Aquatic-phase CRLF, SFGS, SMHM, CTS

Non-Vascular Aquatic Plants (N) There are no exceedances of th e Agency’s LOC for aquatic plants (1.0) Indirect Effects:

Aquatic-phase CRLF, SFGS, SMHM, CTS
Direct Effects: Terrestrial-phase CRLF, SFGS, CTS

Birds, Reptiles, and
Terrestrial-Phase Amphibians (Y) Acute dose diet-based RQs range from 0.15 to 47.0 for short grass; 0.07 to 21.5 for tall grass; 0.08 to 26.4 for broadleaf plants/small insects; 0.01 to 2.9 for fruits/pods/seeds/large insect, and 0.03 to 0.65 for the granivore dietary categories. For short-grass, RQs exceed the Agency’s acute listed species LOC (0.1) in all 20 crop scenarios and at least one RQ in all five dietary categories exceeded the acute listed species LOC (0.1).

Chronic RQs for birds range from 4.0 to 20.0 for short grass; 1.8 to 9.2 for tall grass; 2.3 to 11.3 for broadleaf plants/small insects; and 0.25 to 1.3 for fruits/pods/seeds/large insect dietary categories. For short-gr ass, tall grass, and broadleaf plants/small insect dietary categories, RQs exceed the Agency’s chronic listed species LOC (1.0) in all 20 crop scenarios and at least one RQ in all four dietary categories exceeded the acute listed species LOC (1.0). Indirect Effects:

Terrestrial-phase CRLF, SFGS, SMHM,
SJKF

Mammals (Y) Acute dose-based RQs for mammals range from 2.4 to 26.0 for short grass; 1.1 to 11.9 for tall grass; 1.3 to 14.6 for broadleaf plants/ small insects; 0.15 to 1.6 for fruits/pods/ seeds/large insects; an d 0.03 to 0.36 for the granivore dietary categories. Acute RQs exceed the Agency’s LOC (0.1) for one or more crop scenarios fo r all five dietary categories. Direct Effects:

SMHM; SJKF



### 144

### Table 5.9 Risk Estimation Summary for e ndosulfan - Direct and Indirect Effects

LOC Exceedances Assessed Species Taxa (1) Description of Results of Risk Estimation (Y/N) Potentially Affected Chronic dose-based RQs for mammals range from 31.8 to 347 for short grass; 14.6 to 159 for tall grass; 17.9 to 195 broadleaf plants/small insects; 2.0 to 21.7 for fruits/pods/seeds/large insect; and 0.44 to 4.8 for the granivore dietary categories. Chronic RQs exceed the Agency’s chronic listed species LOC (1.0) in all 20 crop
scenarios for four of the five dietary categories modeled. Indirect Effects:

Terrestrial-phase CRLF, SFGS, SMHM,
SJKF

Direct Effects :

BCB, VELB Terrestrial
Invertebrates (Y) RQs based on EECs for small insects and large insects range from 450 to 2250 and 50 to 250, respectively Indirect Effects :

Terrestrial phase CRLF, SFGS, SMHM, SJKF, CTS

Terrestrial Plants -

Monocots (N; however

effects cannot be quantified) There are no acceptable terres trial plant data available Indirect Effects : CRLF, SFGS, SMHM, BCB, VELB, SJKF, CTS

Terrestrial Plants -
Dicots (N; however

effects cannot be quantified) There are no acceptable terres trial plant data available Indirect Effects : CRLF, SFGS, SMHM, BCB, VELB, SJKF, CTS

(1) Risks to estuarine/marine fish and invertebrate s were not assessed because the listed species for endosulfan do not comprise this taxonomic group nor does available life history and critical habitat information indicate they would be affected indirectly by effects on estuarine/marine species or this
habitat.



### Table 5.10 Risk Estimation Summary for Endosulfan – Effects to Designated Critical Habitat (PCEs)

Taxa (1) May Affect
Habitat

(Y/N) Description of Results of Risk Estimation Species Associated with Designated
Critical Habitat that

May be Modified

Freshwater Fish and Aquatic-phase Amphibians (Y) Acute RQs range from 7.2 to 58.8; exceeding the Agency’s acute listed species LOC (0.05) in all 20 crop scenarios.

Chronic RQs range from 5.7 to 80.6; exceeding the Agency’s chronic species LOC (1.0) in all 20 crop scenarios. CRLF,CTS

Freshwater
Invertebrates (Y) Acute RQs range from 1.2 to 9.8 for freshwater invertebrates; exceeding the Agency’s acute liste d species LOC (0.05) in all 20 crop scenarios.

Chronic RQs range from 23.7 to 260; exceeding the Agency’s chronic species LOC (1.0) in all 20 crop scenarios. CRLF,CTS

Vascular Aquatic
Plants (N; however

effects cannot be quantified) There are no acceptable vascular aquatic plant data available CRLF,CTS

Non-Vascular (N) There are no exceedances of th e Agency’s LOC for aquatic CRLF,CTS



### 145

### Table 5.10 Risk Estimation Summary for Endosulfan – Effects to Designated Critical Habitat (PCEs)

Taxa (1) May Affect
Habitat

(Y/N) Species Associated with Designated Description of Results of Risk Estimation Critical Habitat that May be Modified Aquatic Plants plants (1.0) CRLF,CTS

Birds, Reptiles, and
Terrestrial-Phase Amphibians (Y) Acute dose diet-based RQs range from 0.15 to 47.0 for short grass; 0.07 to 21.5 for tall grass; 0.08 to 26.4 for broadleaf plants/small insects; 0.01 to 2.9 for fruits/pods/seeds/large insect, and 0.03 to 0.65 for the granivore dietary categories. For short-grass, RQs exceed the Agency’s acute listed species LOC (0.1) in all 20 crop scenarios and at least one RQ in all five dietary categories exceeded the acute listed species LOC (0.1).

Chronic RQs for birds range from 4.0 to 20.0 for short grass; 1.8 to 9.2 for tall grass; 2.3 to 11.3 for broadleaf plants/small insects; and 0.25 to 1.3 for fruits/pods/seeds/large insect dietary categories. For short-gr ass, tall grass, and broadleaf plants/small insect dietary categories, RQs exceed the Agency’s chronic listed species LOC (1.0) in all 20 crop scenarios and at least one RQ in all four dietary categories exceeded the acute listed species LOC (1.0). Acute dose-based RQs for mammals range from 2.4 to 26.0 for short grass; 1.1 to 11.9 for tall grass; 1.3 to 14.6 for broadleaf plants/small insects; 0.15 to 1.6 for fruits/pods/seeds/large insects; and 0.03 to 0.36 for the granivore dietary categories. Acute RQs exceed the Agency’s LOC (0.1) for one or more crop scenarios for all five dietary categories. Mammals (Y)

Chronic dose-based RQs for mammals range from 31.8 to 347 for short grass; 14.6 to 159 for tall grass; 17.9 to 195 broadleaf plants/small insects; 2.0 to 21.7 for fruits/pods/seeds/large insect; and 0.44 to 4.8 for the granivore dietary categories. Chronic RQs exceed the Agency’s chronic listed species LOC (1.0) in all 20 crop
scenarios for four of the five dietary categories modeled. CRLF

Terrestrial
Invertebrates (Y) RQs based on EECs for small insects and large insects range from 450 to 2250 and 50 to 250, respectively CRLF,CTS

Terrestrial Plants -

Monocots (N; however

effects cannot be quantified) There are no acceptable terres trial plant data available CRLF,BCB, VELB,
CTS

Terrestrial Plants -
Dicots (N; however

effects cannot be quantified) There are no acceptable terres trial plant data available CRLF,BCB, VELB,
CTS



### Following a “may affect” determination, additio nal information is considered to refine the potential for exposure at th e predicted levels based on th e life history characteristics ( i.e. , habitat range, feed ing preferences, etc .) of the assessed species. Based on the best available information, the Agency uses the re fined evaluation to distinguish those actions

146

### that “may affect, but are not likely to adversel y affect” from those actions that are “likely to adversely affect” the assessed species and its designated cri tical habitat.

The criteria used to make determinations that the effects of an acti on are “not likely to adversely affect” the assessed species or it s designated critical habitat include the following:

• Significance of Effect : Insignificant effects are those that cannot be meaningfully measured, detected, or evaluated in the c ontext of a level of effect where “take” occurs for even a single individual. “T ake” in this context means to harass or harm, defined as the following:

 Harm includes significant habitat m odification or degradation that results in death or injury to listed species by significantly impairing behavioral patterns such as br eeding, feeding, or sheltering.

 Harass is defined as actions that crea te the likelihood of injury to listed species to such an extent as to significantly disrupt normal behavior patterns which include, but are no t limited to, breeding, feeding, or sheltering.

• Likelihood of the Effect Occurring : Discountable effect s are those that are extremely unlikely to occur.

• Adverse Nature of Effect : Effects that are wholly be neficial without any adverse
effects are not considered adverse.

A description of the risk and effects determ ination for each of the established assessment endpoints for the assessed species and their designated critic al habitat is provided in Sections 5.2.1 through 5.2.7 . The effects determination section for each listed species assessed will follow a similar pattern. Each will start with a discussion of the potential for direct effects, followed by a discussion of the potential for indirect effects. The likelihood of effects occurring will be informed by the probit-based chance of individual acute effects for freshwater fish and invertebrates ( Table 5.11 ) , terrestrial birds, mammals and insects ( Table 5.12 ) and herpetofauna based on T-HERPS modeling ( Table 5.13 ). For those listed species that have designated critical habitat, the section will end with a discussion on the potential for effects to the critical habitat from the use
of endosulfan.

147

### 148 Table 5.11 Summary of the chance of individual acute effects to freshwater animals based on acute RQs, the acute listed species LOC, acute toxicity data, and probit slope response relationships (1,2)



### .

Use Category Run
No. Acute FW Fish RQ Change of Individual Effect at RQ or LOC Based on Probit Slope & Slope's 95% CI Acute FW Invert. RQ Change of Individual Effect at RQ or LOC Based on Probit Slope & Slope's 95% CI

N/A N/A LOC =
0.05 1 in 4.18E+18

(1 in 216, 1 in 1.75E+31) LOC = 0.05 1 in 4.18E+18

(1 in 216, 1 in 1.75E+31)

Almonds, Hazelnuts &
Walnuts 1 33.50 1 in 1.00

(1 in 1.00, 1 in 1.00) 5.58 1 in 1.00

(1 in 1.07, 1 in 1.00)

Citrus 1 33.50 1 in 1.00

(1 in 1.00, 1 in 1.00) 5.58 1 in 1.00

(1 in 1.07, 1 in 1.00)

Broccoli, Cabbage & Cauliflower 1 48.10 1 in 1.00

(1 in 1.00, 1 in 1.00) 8.02 1 in 1.00

(1 in 1.04, 1 in 1.00)

Collards, Kale & Mustard Green 2 16.70 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.78 1 in 1.02

(1 in 1.23, 1 in 1.00)

Sweet corn for fresh market only 1 28.80 1 in 1.00

(1 in 1.00, 1 in 1.00) 4.80 1 in 1.00

(1 in 1.09, 1 in 1.00)

Cotton (ground) 2 12.40 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.07 1 in 1.08

(1 in 1.36, 1 in 1.00)

Cotton (aerial) 3 15.60 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.60 1 in 1.03

(1 in 1.26, 1 in 1.00)

All fruit trees 1 34.00 1 in 1.00

(1 in 1.00, 1 in 1.00) 5.67 1 in 1.00

(1 in 1.07, 1 in 1.00)

Lettuce & Brussels Sprouts 1 58.80 1 in 1.00

(1 in 1.00, 1 in 1.00) 9.80 1 in 1.00

(1 in 1.02, 1 in 1.00)

Cucurbits 1 15.50 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.58 1 in 1.03

(1 in 1.26, 1 in 1.00)

Eggplant 3 7.20 1 in 1.00

(1 in 1.05, 1 in 1.00) 1.20 1 in 1.56

(1 in 1.78, 1 in 1.31)

Ornamentals or Shade Trees (Southern Coast) 1 34.30 1 in 1.00

(1 in 1.00, 1 in 1.00) 5.72 1 in 1.00

(1 in 1.07, 1 in 1.00)

Ornamentals or Shade Trees (Northern Central coast) 1 Add 43.80 1 in 1.00

(1 in 1.00, 1 in 1.00) 7.30 1 in 1.00

(1 in 1.04, 1 in 1.00)

Potato 1 18.90 1 in 1.00

(1 in 1.01, 1 in 1.00) 3.15 1 in 1.01

(1 in 1.19, 1 in 1.00)
Potato (Northern Central coast) 1 Add 26.30 1 in 1.00 4.38 1 in 1.00

### 149 Use Category Run
No. Acute FW Fish RQ Change of Individual Effect at RQ or LOC Based on Probit Slope & Slope's 95% CI Acute FW Invert. RQ Change of Individual Effect at RQ or LOC Based on Probit Slope & Slope's 95% CI (1 in 1.00, 1 in 1.00) (1 in 1.11, 1 in 1.00)

Sweet Potato 3 11.80 1 in 1.00

(1 in 1.02, 1 in 1.00) 1.97 1 in 1.10

(1 in 1.39, 1 in 1.00)

Beans & Peas (dry) & Pepper 1 20.00 1 in 1.00

(1 in 1.00, 1 in 1.00) 3.33 1 in 1.01

(1 in 1.17, 1 in 1.00)

Carrot & Celery 2 17.20 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.87 1 in 1.02

(1 in 1.22, 1 in 1.00)

Strawberry 1 36.40 1 in 1.00

(1 in 1.00, 1 in 1.00) 6.07 1 in 1.00

(1 in 1.06, 1 in 1.00)

Tomato 1 17.90 1 in 1.00

(1 in 1.01, 1 in 1.00) 2.98 1 in 1.02

(1 in 1.21, 1 in 1.00)

(1) Bolded RQs exceed the Agen cy’s acute listed species LOC (0.05 for aquatic anim als). When acute RQs exce ed the Agency’s listed species LOC, the chance of individual effects was calculated at the RQ and the LOC, whereas if there was no exceedance, then th e chance of individual effects was calculated only at the LOC.

(2) Although an LC50 or an EC50 has been established for all aqua tic taxonomic groups, information is unavailable to estimate prob it slopes from the studies from which the endpoi nts were derived. Therefore, a default sl ope of 4.5 with an assumed 95% confidenc e interval of 2 and 9 has been assumed as per original Agency assumptions of typical slope cited in Urban and Cook (1986).Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIInsectAcuteRQChance ofIndividual Effectat RQ or LOCBased on ProbitSlope & Slope's95% CIN/AN/ALOC =0.11 in 1.05E+17(1 in 6290, 1 in3.31E+40)LOC = 0.11 in 2.94E+05(1 in 44, 1 in8.86E+18)LOC =0.11 in 2.94E+05(1 in 44, 1 in8.86E+18)LOC =0.051 in 29(1 in 154, 1 in1220)Short Grass37.601 in 1.00(1 in 1.00, 1 in 1.00)20.821 in 1.00(1 in 1.00, 1 in 1.00)9.531 in 1.00(1 in 1.03, 1 in 1.00)Tall Grass17.231 in 1.00(1 in 1.00, 1 in 1.00)9.541 in 1.00(1 in 1.03, 1 in 1.00)4.371 in 1.00(1 in 1.11, 1 in 1.00)Broadleaf Plants/ Small Insects21.151 in 1.00(1 in 1.00, 1 in 1.00)11.711 in 1.00(1 in 1.02, 1 in 1.00)5.361 in 1.00(1 in 1.08, 1 in 1.00)18001 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects2.351 in 1.00(1 in 1.10, 1 in 1.00)1.301 in 1.44(1 in 1.69, 1 in 1.18)0.601 in 6.42(1 in 3.06, 1 in 46.49)2001 in 1.00(1 in 1.00, 1 in1.00)Almonds,hazelnut &walnutGranivore0.521 in 121.33(1 in 6.46, 1 in1.28E+04)0.291 in 130.50(1 in 7.11, 1 in1.61E+06)0.131 in 2.57E+04(1 in 25.29, 1 in7.31E+14)Short Grass47.001 in 1.00(1 in 1.00, 1 in 1.00)26.031 in 1.00(1 in 1.00, 1 in 1.00)11.921 in 1.00(1 in 1.02, 1 in 1.00)Tall Grass21.541 in 1.00(1 in 1.00, 1 in 1.00)11.931 in 1.00(1 in 1.02, 1 in 1.00)5.461 in 1.00(1 in 1.08, 1 in 1.00)Broadleaf Plants/ Small Insects26.441 in 1.00(1 in 1.00, 1 in 1.00)14.641 in 1.00(1 in 1.01, 1 in 1.00)6.701 in 1.00(1 in 1.05, 1 in 1.00)22501 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects2.941 in 1.00(1 in 1.05, 1 in 1.00)1.631 in 1.21(1 in 1.51, 1 in 1.03)0.741 in 3.54(1 in 2.51, 1 in 8.01)2501 in 1.00(1 in 1.00, 1 in1.00)CitrusGranivore0.651 in 17.33(1 in 3.96, 1 in153.00)0.361 in 42.78(1 in 5.31, 1 in2.87E+04)0.171 in 4.55E+03(1 in 16.92, 1 in9.70E+11)Short Grass24.391 in 1.00(1 in 1.00, 1 in 1.00)13.511 in 1.00(1 in 1.01, 1 in 1.00)6.181 in 1.00(1 in 1.06, 1 in 1.00)Broccoli,cabbage,Chinesecabbage,Tall Grass11.181 in 1.00(1 in 1.00, 1 in 1.00)6.191 in 1.00(1 in 1.06, 1 in 1.00)2.831 in 1.02(1 in 1.22, 1 in 1.00)150Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIBroadleaf Plants/ Small Insects13.721 in 1.00(1 in 1.00, 1 in 1.00)7.601 in 1.00(1 in 1.04, 1 in 1.00)3.481 in 1.01(1 in 1.16, 1 in 1.00)11681 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.521 in 1.06(1 in 1.34, 1 in 1.01)0.841 in 2.70(1 in 2.26, 1 in 3.94)0.391 in 31.64(1 in 4.89, 1 in9.86E+03)1301 in 1.00(1 in 1.00, 1 in1.00)cauliflower,kohlrabiGranivore0.341 in 3.10E+04(1 in 22.08, 1 in6.70E+09)0.191 in 1.86E+03(1 in 13.69, 1 in3.27E+10)0.09Short Grass14.101 in 1.00(1 in 1.00, 1 in 1.00)7.811 in 1.00(1 in 1.04, 1 in 1.00)3.581 in 1.01(1 in 1.16, 1 in 1.00)Tall Grass6.461 in 1.00(1 in 1.00, 1 in 1.00)3.581 in 1.01(1 in 1.15, 1 in 1.00)1.641 in 1.20(1 in 1.50, 1 in 1.03)Broadleaf Plants/ Small Insects7.931 in 1.00(1 in 1.00, 1 in 1.00)4.391 in 1.00(1 in 1.11, 1 in 1.00)2.011 in 1.09(1 in 1.37, 1 in 1.00)6751 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects0.881 in 3.12(1 in 2.37, 1 in 4.33)0.491 in 12.43(1 in 3.75, 1 in396.26)0.221 in 587.41(1 in 10.36, 1 in4.25E+08)751 in 1.00(1 in 1.00, 1 in1.00)Kale,Collards &MustardGreenGranivore0.201 in 1.14E+09(1 in 185.19, 1 in8.52E+20)0.111 in 1.41E+05(1 in 37.27, 1 in5.18E+17)0.05Short Grass28.201 in 1.00(1 in 1.00, 1 in 1.00)15.621 in 1.00(1 in 1.01, 1 in 1.00)7.151 in 1.00(1 in 1.05, 1 in 1.00)Tall Grass12.931 in 1.00(1 in 1.00, 1 in 1.00)7.161 in 1.00(1 in 1.05, 1 in 1.00)3.281 in 1.01(1 in 1.18, 1 in 1.00)Broadleaf Plants/ Small Insects15.861 in 1.00(1 in 1.00, 1 in 1.00)8.781 in 1.00(1 in 1.03, 1 in 1.00)4.021 in 1.00(1 in 1.13, 1 in 1.00)13501 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.761 in 1.02(1 in 1.23, 1 in 1.00)0.981 in 2.08(1 in 2.03, 1 in 2.16)0.451 in 17.32(1 in 4.13, 1 in1.22E+03)1501 in 1.00(1 in 1.00, 1 in1.00)Sweet cornGranivore0.391 in 3.70E+03(1 in 14.00, 1 in4.07E+07)0.221 in 709.49(1 in 10.85, 1 in8.62E+08)0.10151Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIShort Grass18.801 in 1.00(1 in 1.00, 1 in 1.00)10.411 in 1.00(1 in 1.02, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)Tall Grass8.621 in 1.00(1 in 1.00, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)2.181 in 1.07(1 in 1.33, 1 in 1.00)Broadleaf Plants/ Small Insects10.581 in 1.00(1 in 1.00, 1 in 1.00)5.861 in 1.00(1 in 1.07, 1 in 1.00)2.681 in 1.03(1 in 1.24, 1 in 1.00)9001 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.181 in 1.38(1 in 1.67, 1 in 1.21)0.651 in 4.99(1 in 2.82, 1 in21.50)0.301 in 111.34(1 in 6.83, 1 in9.03E+05)1001 in 1.00(1 in 1.00, 1 in1.00)Cotton(ground)Granivore0.261 in 2.79E+06(1 in 55.89, 1 in3.62E+14)0.141 in 1.27E+04(1 in 21.50, 1 in4.90E+13)0.07Short Grass18.291 in 1.00(1 in 1.00, 1 in 1.00)10.131 in 1.00(1 in 1.02, 1 in 1.00)4.641 in 1.00(1 in 1.10, 1 in 1.00)Tall Grass8.381 in 1.00(1 in 1.00, 1 in 1.00)4.641 in 1.00(1 in 1.10, 1 in 1.00)2.131 in 1.08(1 in 1.34, 1 in 1.00)Broadleaf Plants/ Small Insects10.291 in 1.00(1 in 1.00, 1 in 1.00)5.701 in 1.00(1 in 1.07, 1 in 1.00)2.611 in 1.03(1 in 1.25, 1 in 1.00)8761 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.141 in 1.45(1 in 1.72, 1 in 1.28)0.631 in 5.38(1 in 2.89, 1 in27.03)0.291 in 128.84(1 in 7.09, 1 in1.54E+06)971 in 1.00(1 in 1.00, 1 in1.00)Cotton(Areal)Granivore0.251 in 4.72E+06(1 in 62.15, 1 in1.30E+15)0.141 in 1.58E+04(1 in 22.60, 1 in1.12E+14)0.06Short Grass47.001 in 1.00(1 in 1.00, 1 in 1.00)26.031 in 1.00(1 in 1.00, 1 in 1.00)11.921 in 1.00(1 in 1.02, 1 in 1.00)Tall Grass21.541 in 1.00(1 in 1.00, 1 in 1.00)11.931 in 1.00(1 in 1.02, 1 in 1.00)5.461 in 1.00(1 in 1.08, 1 in 1.00)ApplesBroadleaf Plants/ Small Insects26.441 in 1.00(1 in 1.00, 1 in 1.00)14.641 in 1.00(1 in 1.01, 1 in 1.00)6.701 in 1.00(1 in 1.05, 1 in 1.00)22501 in 1.00(1 in 1.00, 1 in1.00)152Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIFruits/Pods/ Seeds/ Large Insects2.941 in 1.00(1 in 1.05, 1 in 1.00)1.631 in 1.21(1 in 1.51, 1 in 1.03)0.741 in 3.54(1 in 2.51, 1 in 8.01)2501 in 1.00(1 in 1.00, 1 in1.00)Granivore0.651 in 17.33(1 in 3.96, 1 in153.00)0.361 in 42.78(1 in 5.31, 1 in2.87E+04)0.171 in 4.55E+03(1 in 16.92, 1 in9.70E+11)Short Grass47.001 in 1.00(1 in 1.00, 1 in 1.00)26.031 in 1.00(1 in 1.00, 1 in 1.00)11.921 in 1.00(1 in 1.02, 1 in 1.00)Tall Grass21.541 in 1.00(1 in 1.00, 1 in 1.00)11.931 in 1.00(1 in 1.02, 1 in 1.00)5.461 in 1.00(1 in 1.08, 1 in 1.00)Broadleaf Plants/ Small Insects26.441 in 1.00(1 in 1.00, 1 in 1.00)14.641 in 1.00(1 in 1.01, 1 in 1.00)6.701 in 1.00(1 in 1.05, 1 in 1.00)22501 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects2.941 in 1.00(1 in 1.05, 1 in 1.00)1.631 in 1.21(1 in 1.51, 1 in 1.03)0.741 in 3.54(1 in 2.51, 1 in 8.01)2501 in 1.00(1 in 1.00, 1 in1.00)Apricot,nectarine,peach,cherry, pear,plum & pruneGranivore0.651 in 17.33(1 in 3.96, 1 in153.00)0.361 in 42.78(1 in 5.31, 1 in2.87E+04)0.171 in 4.55E+03(1 in 16.92, 1 in9.70E+11)0Short Grass26.711 in 1.00(1 in 1.00, 1 in 1.00)14.791 in 1.00(1 in 1.01, 1 in 1.00)6.771 in 1.00(1 in 1.05, 1 in 1.00)Tall Grass12.241 in 1.00(1 in 1.00, 1 in 1.00)6.781 in 1.00(1 in 1.05, 1 in 1.00)3.101 in 1.01(1 in 1.19, 1 in 1.00)Broadleaf Plants/ Small Insects15.021 in 1.00(1 in 1.00, 1 in 1.00)8.321 in 1.00(1 in 1.03, 1 in 1.00)3.811 in 1.00(1 in 1.14, 1 in 1.00)12781 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.671 in 1.03(1 in 1.27, 1 in 1.00)0.921 in 2.28(1 in 2.12, 1 in 2.64)0.421 in 21.54(1 in 4.39, 1 in2.57E+03)1421 in 1.00(1 in 1.00, 1 in1.00)Lettuce &BrusselssproutsGranivore0.371 in 7.97E+03(1 in 16.53, 1 in2.55E+08)0.211 in 1.01E+03(1 in 11.82, 1 in3.25E+09)0.09Cucumber,melons,pumpkin &Short Grass24.391 in 1.00(1 in 1.00, 1 in 1.00)13.511 in 1.00(1 in 1.01, 1 in 1.00)6.181 in 1.00(1 in 1.06, 1 in 1.00)153Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CITall Grass11.181 in 1.00(1 in 1.00, 1 in 1.00)6.191 in 1.00(1 in 1.06, 1 in 1.00)2.831 in 1.02(1 in 1.22, 1 in 1.00)Broadleaf Plants/ Small Insects13.721 in 1.00(1 in 1.00, 1 in 1.00)7.601 in 1.00(1 in 1.04, 1 in 1.00)3.481 in 1.01(1 in 1.16, 1 in 1.00)11681 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.521 in 1.06(1 in 1.34, 1 in 1.01)0.841 in 2.70(1 in 2.26, 1 in 3.94)0.391 in 31.64(1 in 4.89, 1 in9.86E+03)1301 in 1.00(1 in 1.00, 1 in1.00)squashGranivore0.341 in 3.10E+04(1 in 22.08, 1 in6.70E+09)0.191 in 1.86E+03(1 in 13.69, 1 in3.27E+10)0.09Short Grass9.401 in 1.00(1 in 1.00, 1 in 1.00)5.211 in 1.00(1 in 1.08, 1 in 1.00)2.381 in 1.05(1 in 1.29, 1 in 1.00)Tall Grass4.311 in 1.00(1 in 1.01, 1 in 1.00)2.391 in 1.05(1 in 1.29, 1 in 1.00)1.091 in 1.76(1 in 1.88, 1 in 1.57)Broadleaf Plants/ Small Insects5.291 in 1.00(1 in 1.00, 1 in 1.00)2.931 in 1.02(1 in 1.21, 1 in 1.00)1.341 in 1.40(1 in 1.67, 1 in 1.14)4501 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects0.591 in 40.31(1 in 4.93, 1 in1.02E+03)0.331 in 70.91(1 in 6.07, 1 in1.75E+05)0.151 in 1.01E+04(1 in 20.37, 1 in2.02E+13)501 in 1.00(1 in 1.01, 1 in1.00)EggplantGranivore0.131 in 3.53E+13(1 in 1.37E+03, 1 in9.08E+31)0.071 in 7.05E+06(1 in 88.87, 1 in2.03E+24)0.03Short Grass11.421 in 1.00(1 in 1.00, 1 in 1.00)6.321 in 1.00(1 in 1.06, 1 in 1.00)2.901 in 1.02(1 in 1.22, 1 in 1.00)Tall Grass5.231 in 1.00(1 in 1.00, 1 in 1.00)2.901 in 1.02(1 in 1.22, 1 in 1.00)1.331 in 1.41(1 in 1.67, 1 in 1.16)Broadleaf Plants/ Small Insects6.421 in 1.00(1 in 1.00, 1 in 1.00)3.561 in 1.01(1 in 1.16, 1 in 1.00)1.631 in 1.21(1 in 1.51, 1 in 1.03)5471 in 1.00(1 in 1.00, 1 in1.00)Ornamentals& shadetreesFruits/Pods/ Seeds/ Large Insects0.711 in 9.39(1 in 3.34, 1 in 40.29)0.401 in 28.72(1 in 4.76, 1 in7.02E+03)0.181 in 2.40E+03(1 in 14.54, 1 in8.48E+10)611 in 1.00(1 in 1.01, 1 in1.00)154Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIGranivore0.161 in 1.88E+11(1 in 501.26, 1 in2.34E+26)0.091 in 1.00E+06(1 in 57.77, 1 in1.02E+21)0.04Short Grass26.711 in 1.00(1 in 1.00, 1 in 1.00)14.791 in 1.00(1 in 1.01, 1 in 1.00)6.771 in 1.00(1 in 1.05, 1 in 1.00)Tall Grass12.241 in 1.00(1 in 1.00, 1 in 1.00)6.781 in 1.00(1 in 1.05, 1 in 1.00)3.101 in 1.01(1 in 1.19, 1 in 1.00)Broadleaf Plants/ Small Insects15.021 in 1.00(1 in 1.00, 1 in 1.00)8.321 in 1.00(1 in 1.03, 1 in 1.00)3.811 in 1.00(1 in 1.14, 1 in 1.00)12781 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.671 in 1.03(1 in 1.27, 1 in 1.00)0.921 in 2.28(1 in 2.12, 1 in 2.64)0.421 in 21.54(1 in 4.39, 1 in2.57E+03)1421 in 1.00(1 in 1.00, 1 in1.00)PotatoGranivore0.371 in 7.97E+03(1 in 16.53, 1 in2.55E+08)0.211 in 1.01E+03(1 in 11.82, 1 in3.25E+09)0.09Short Grass15.011 in 1.00(1 in 1.00, 1 in 1.00)8.311 in 1.00(1 in 1.03, 1 in 1.00)3.811 in 1.00(1 in 1.14, 1 in 1.00)Tall Grass6.881 in 1.00(1 in 1.00, 1 in 1.00)3.811 in 1.00(1 in 1.14, 1 in 1.00)1.741 in 1.16(1 in 1.46, 1 in 1.02)Broadleaf Plants/ Small Insects8.451 in 1.00(1 in 1.00, 1 in 1.00)4.681 in 1.00(1 in 1.10, 1 in 1.00)2.141 in 1.07(1 in 1.34, 1 in 1.00)7191 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects0.941 in 2.46(1 in 2.17, 1 in 2.81)0.521 in 9.96(1 in 3.51, 1 in190.27)0.241 in 398.57(1 in 9.42, 1 in9.99E+07)801 in 1.00(1 in 1.00, 1 in1.00)Sweet potatoGranivore0.211 in 2.79E+08(1 in 140.36, 1 in2.73E+19)0.121 in 8.14E+04(1 in 32.90, 1 in6.17E+16)0.05Short Grass26.711 in 1.00(1 in 1.00, 1 in 1.00)14.791 in 1.00(1 in 1.01, 1 in 1.00)6.771 in 1.00(1 in 1.05, 1 in 1.00)Dry beans(exceptLima), peas& pepperTall Grass12.241 in 1.00(1 in 1.00, 1 in 1.00)6.781 in 1.00(1 in 1.05, 1 in 1.00)3.101 in 1.01(1 in 1.19, 1 in 1.00)155Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIBroadleaf Plants/ Small Insects15.021 in 1.00(1 in 1.00, 1 in 1.00)8.321 in 1.00(1 in 1.03, 1 in 1.00)3.811 in 1.00(1 in 1.14, 1 in 1.00)12781 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.671 in 1.03(1 in 1.27, 1 in 1.00)0.921 in 2.28(1 in 2.12, 1 in 2.64)0.421 in 21.54(1 in 4.39, 1 in2.57E+03)1421 in 1.00(1 in 1.00, 1 in1.00)Granivore0.371 in 7.97E+03(1 in 16.53, 1 in2.55E+08)0.211 in 1.01E+03(1 in 11.82, 1 in3.25E+09)0.09Short Grass18.801 in 1.00(1 in 1.00, 1 in 1.00)10.411 in 1.00(1 in 1.02, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)Tall Grass8.621 in 1.00(1 in 1.00, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)2.181 in 1.07(1 in 1.33, 1 in 1.00)Broadleaf Plants/ Small Insects10.581 in 1.00(1 in 1.00, 1 in 1.00)5.861 in 1.00(1 in 1.07, 1 in 1.00)2.681 in 1.03(1 in 1.24, 1 in 1.00)9001 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.181 in 1.38(1 in 1.67, 1 in 1.21)0.651 in 4.99(1 in 2.82, 1 in21.50)0.301 in 111.34(1 in 6.83, 1 in9.03E+05)1001 in 1.00(1 in 1.00, 1 in1.00)CarrotGranivore0.261 in 2.79E+06(1 in 55.89, 1 in3.62E+14)0.141 in 1.27E+04(1 in 21.50, 1 in4.90E+13)0.07Short Grass18.801 in 1.00(1 in 1.00, 1 in 1.00)10.411 in 1.00(1 in 1.02, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)Tall Grass8.621 in 1.00(1 in 1.00, 1 in 1.00)4.771 in 1.00(1 in 1.10, 1 in 1.00)2.181 in 1.07(1 in 1.33, 1 in 1.00)Broadleaf Plants/ Small Insects10.581 in 1.00(1 in 1.00, 1 in 1.00)5.861 in 1.00(1 in 1.07, 1 in 1.00)2.681 in 1.03(1 in 1.24, 1 in 1.00)9001 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.181 in 1.38(1 in 1.67, 1 in 1.21)0.651 in 4.99(1 in 2.82, 1 in21.50)0.301 in 111.34(1 in 6.83, 1 in9.03E+05)1001 in 1.00(1 in 1.00, 1 in1.00)CeleryGranivore0.261 in 2.79E+06(1 in 55.89, 1 in3.62E+14)0.141 in 1.27E+04(1 in 21.50, 1 in4.90E+13)0.07156Table 5.12 Summary of the chance of individual acute effects toterrestrial animals based on acute RQs, the acute listed species LOC,acute toxicity data, and probit slope response relationships.UseCategoryDietary Category20 gBirdAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CI15 gMammalAcute RQChance ofIndividual Effect atRQ or LOC Basedon Probit Slope &Slope's 95% CI1000 gMammalAcuteRQChance of IndividualEffect at RQ or LOCBased on ProbitSlope & Slope's 95%CIChance ofIndividual EffectInsectat RQ or LOCAcuteBased on ProbitRQSlope & Slope's95% CIShort Grass20.201 in 1.00(1 in 1.00, 1 in 1.00)11.191 in 1.00(1 in 1.02, 1 in 1.00)5.121 in 1.00(1 in 1.08, 1 in 1.00)Tall Grass9.261 in 1.00(1 in 1.00, 1 in 1.00)5.131 in 1.00(1 in 1.08, 1 in 1.00)2.351 in 1.05(1 in 1.30, 1 in 1.00)Broadleaf Plants/ Small Insects11.361 in 1.00(1 in 1.00, 1 in 1.00)6.291 in 1.00(1 in 1.06, 1 in 1.00)2.881 in 1.02(1 in 1.22, 1 in 1.00)9671 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.261 in 1.24(1 in 1.56, 1 in 1.10)0.701 in 4.13(1 in 2.65, 1 in12.37)0.321 in 76.94(1 in 6.20, 1 in2.36E+05)1071 in 1.00(1 in 1.00, 1 in1.00)StrawberryGranivore0.281 in 7.40E+05(1 in 42.65, 1 in1.44E+13)0.161 in 7.31E+03(1 in 18.90, 1 in5.91E+12)0.07Short Grass24.391 in 1.00(1 in 1.00, 1 in 1.00)13.511 in 1.00(1 in 1.01, 1 in 1.00)6.181 in 1.00(1 in 1.06, 1 in 1.00)Tall Grass11.181 in 1.00(1 in 1.00, 1 in 1.00)6.191 in 1.00(1 in 1.06, 1 in 1.00)2.831 in 1.02(1 in 1.22, 1 in 1.00)Broadleaf Plants/ Small Insects13.721 in 1.00(1 in 1.00, 1 in 1.00)7.601 in 1.00(1 in 1.04, 1 in 1.00)3.481 in 1.01(1 in 1.16, 1 in 1.00)11681 in 1.00(1 in 1.00, 1 in1.00)Fruits/Pods/ Seeds/ Large Insects1.521 in 1.06(1 in 1.34, 1 in 1.01)0.841 in 2.70(1 in 2.26, 1 in 3.94)0.391 in 31.64(1 in 4.89, 1 in9.86E+03)1301 in 1.00(1 in 1.00, 1 in1.00)TomatoGranivore0.341 in 3.10E+04(1 in 22.08, 1 in6.70E+09)0.191 in 1.86E+03(1 in 13.69, 1 in3.27E+10)0.09(1)Bolded RQs exceed the Agency’s acute listed species LOC (0.1 for terrestrialanimals). When acute RQsexceed the Agency’s listed species LOC, the chance of individual effects was calculated at the RQ and the LOC,whereas if there was no exceedance, then the chance of individual effects was calculated only at the LOC.(2)Although an LD50 has been established for all terrestrial taxonomic groups, information is unavailable to estimate probit slopes from the mammal studies from which the endpoints were derived. Therefore, a default slopeof 4.5 with an assumed 95% confidence interval of 2 and 9 has been assumed as per original Agency assumptions of typical slopecited in Urban and Cook (1986). The probit slope for the bird acute LD50 was 8.5 with 95%confidence limits of 3.6 and 13.4. The probit slope for the insect was 1.91 with 95% confidence intervals of 1.40 and 2.42.157Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC,acutetoxicity data, and probitslope response relationships.Use CategoryDietary Category1.4 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI35 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI238 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CIN/AN/ALOC =0.11 in 1.05E+17(1 in 6290, 1 in 3.31E+40)LOC =0.11 in 1.05E+17(1 in 6290, 1 in 3.31E+40)LOC =0.11 in 1.05E+17(1 in 6290, 1 in 3.31E+40)Broadleaf Plants/Small Insects1.081 in 1.65(1 in 1.83, 1 in 1.51)0.651 in 18.60(1 in 4.04, 1 in 179.07)0.321 in 7.49E+04(1 in 26.57, 1 in 5.61E+10)Fruits/Pods/Seeds/Large Insects0.121 in 4.56E+14(1 in 2.24E+03, 1 in 4.94E+34)0.070.04Small Herbivore Mammals11.641 in 1.00(1 in 1.00, 1 in 1.00)1.371 in 1.14(1 in 1.45, 1 in 1.04)Small Insectivore Mammal0.731 in 8.34(1 in 3.23, 1 in 31.32)0.09Almonds, hazelnut &walnutSmall Amphibians0.020.01Broadleaf Plants/Small Insects1.341 in 1.16(1 in 1.47, 1 in 1.04)0.811 in 4.63(1 in 2.71, 1 in 9.28)0.401 in 2.72E+03(1 in 13.09, 1 in 1.95E+07)Fruits/Pods/Seeds/Large Insects0.151 in 8.99E+11(1 in 678.21, 1 in 1.09E+28)0.090.04Small Herbivore Mammals14.551 in 1.00(1 in 1.00, 1 in 1.00)1.711 in 1.02(1 in 1.25, 1 in 1.00)Small Insectivore Mammal0.911 in 2.76(1 in 2.27, 1 in 3.45)0.111 in 1.30E+16(1 in 4.23E+03, 1 in 1.90E+38)CitrusSmall Amphibians0.030.01Broadleaf Plants/Small Insects0.701 in 10.90(1 in 3.49, 1 in 55.57)0.421 in 1.49E+03(1 in 11.47, 1 in 4.68E+06)0.211 in 2.98E+08(1 in 142.18, 1 in 3.21E+19)Fruits/Pods/Seeds/Large Insects0.080.050.02Small Herbivore Mammals7.551 in 1.00(1 in 1.00, 1 in 1.00)0.891 in 3.03(1 in 2.35, 1 in 4.10)Small Insectivore Mammal0.471 in 360.53(1 in 8.33, 1 in 1.63E+05)0.06Broccoli, cabbage,Chinese cabbage,cauliflower, kohlrabiSmall Amphibians0.010.01Broadleaf Plants/Small Insects0.401 in 2.50E+03(1 in 12.86, 1 in 1.60E+07)0.241 in 1.18E+07(1 in 74.77, 1 in 1.21E+16)0.121 in 3.81E+14(1 in 2.16E+03, 1 in 3.17E+34)Fruits/Pods/Seeds/Large Insects0.040.030.01Small Herbivore Mammals4.361 in 1.00(1 in 1.01, 1 in 1.00)0.511 in 145.19(1 in 6.74, 1 in 1.94E+04)Kale, Collards &Mustard GreenSmall Insectivore Mammal0.271 in 1.24E+06(1 in 47.37, 1 in 5.00E+13)0.03158Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC,acutetoxicity data, and probitslope response relationships.Use CategoryDietary Category1.4 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI35 gHerp.AcuteRQ238 gChance of Individual Effect atChance of Individual Effect atHerp.RQ or LOC Based on ProbitRQ or LOC Based on ProbitAcuteSlope & Slope's 95% CISlope & Slope's 95% CIRQSmall Amphibians0.010.004Broadleaf Plants/Small Insects0.811 in 4.68(1 in 2.72, 1 in 9.50)0.481 in 264.86(1 in 7.76, 1 in 7.89E+04)0.241 in 1.40E+07(1 in 77.40, 1 in 1.85E+16)Fruits/Pods/Seeds/Large Insects0.090.050.03Small Herbivore Mammals8.731 in 1.00(1 in 1.00, 1 in 1.00)1.031 in 1.86(1 in 1.94, 1 in 1.79)Small Insectivore Mammal0.551 in 79.19(1 in 5.83, 1 in 4.76E+03)0.06Sweet cornSmall Amphibians0.020.01Broadleaf Plants/Small Insects0.541 in 91.07(1 in 6.03, 1 in 6.58E+03)0.321 in 6.52E+04(1 in 25.81, 1 in 4.01E+10)0.161 in 1.44E+11(1 in 475.86, 1 in 1.21E+26)Fruits/Pods/Seeds/Large Insects0.060.040.02Small Herbivore Mammals5.821 in 1.00(1 in 1.00, 1 in 1.00)0.681 in 12.41(1 in 3.62, 1 in 73.56)Small Insectivore Mammal0.361 in 1.06E+04(1 in 17.58, 1 in 5.08E+08)0.04Cotton (ground)Small Amphibians0.010.01Broadleaf Plants/Small Insects0.521 in 119.41(1 in 6.43, 1 in 1.23E+04)0.311 in 1.02E+05(1 in 28.34, 1 in 1.18E+11)0.161 in 2.90E+11(1 in 545.19, 1 in 6.79E+26)Fruits/Pods/Seeds/Large Insects0.060.030.02Small Herbivore Mammals5.661 in 1.00(1 in 1.00, 1 in 1.00)0.671 in 15.03(1 in 3.81, 1 in 111.89)Small Insectivore Mammal0.351 in 1.60E+04(1 in 19.18, 1 in 1.35E+09)0.04Cotton (Areal)Small Amphibians0.010.01Broadleaf Plants/Small Insects1.341 in 1.16(1 in 1.47, 1 in 1.04)0.811 in 4.63(1 in 2.71, 1 in 9.28)0.401 in 2.72E+03(1 in 13.09, 1 in 1.95E+07)Fruits/Pods/Seeds/Large Insects0.151 in 8.99E+11(1 in 678.21, 1 in 1.09E+28)0.090.04Small Herbivore Mammals14.551 in 1.00(1 in 1.00, 1 in 1.00)1.711 in 1.02(1 in 1.25, 1 in 1.00)Small Insectivore Mammal0.911 in 2.76(1 in 2.27, 1 in 3.45)0.111 in 1.30E+16(1 in 4.23E+03, 1 in 1.90E+38)ApplesSmall Amphibians0.030.01Apricot, nectarine,peach, cherry, pear,Broadleaf Plants/Small Insects1.341 in 1.16(1 in 1.47, 1 in 1.04)0.811 in 4.63(1 in 2.71, 1 in 9.28)0.401 in 2.72E+03(1 in 13.09, 1 in 1.95E+07)159Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC,acutetoxicity data, and probitslope response relationships.Use CategoryDietary Category1.4 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI35 gHerp.AcuteRQ238 gChance of Individual Effect atChance of Individual Effect atHerp.RQ or LOC Based on ProbitRQ or LOC Based on ProbitAcuteSlope & Slope's 95% CISlope & Slope's 95% CIRQFruits/Pods/Seeds/Large Insects0.151 in 8.99E+11(1 in 678.21, 1 in 1.09E+28)0.090.04Small Herbivore Mammals14.551 in 1.00(1 in 1.00, 1 in 1.00)1.711 in 1.02(1 in 1.25, 1 in 1.00)Small Insectivore Mammal0.911 in 2.76(1 in 2.27, 1 in 3.45)0.111 in 1.30E+16(1 in 4.23E+03, 1 in 1.90E+38)plum & pruneSmall Amphibians0.030.01Broadleaf Plants/Small Insects0.761 in 6.26(1 in 2.97, 1 in 17.15)0.461 in 491.37(1 in 8.94, 1 in 3.37E+05)0.231 in 4.27E+07(1 in 96.71, 1 in 2.80E+17)Fruits/Pods/Seeds/Large Insects0.080.050.03Small Herbivore Mammals8.261 in 1.00(1 in 1.00, 1 in 1.00)0.971 in 2.18(1 in 2.07, 1 in 2.30)Small Insectivore Mammal0.521 in 135.66(1 in 6.63, 1 in 1.66E+04)0.06Lettuce & BrusselssproutsSmall Amphibians0.020.01Broadleaf Plants/Small Insects0.701 in 10.90(1 in 3.49, 1 in 55.57)0.421 in 1.49E+03(1 in 11.47, 1 in 4.68E+06)0.211 in 2.98E+08(1 in 142.18, 1 in 3.21E+19)Fruits/Pods/Seeds/Large Insects0.080.050.02Small Herbivore Mammals7.551 in 1.00(1 in 1.00, 1 in 1.00)0.891 in 3.03(1 in 2.35, 1 in 4.10)Small Insectivore Mammal0.471 in 360.53 (1 in 8.33, 1 in1.63E+05)0.06Cucumber, melons,pumpkin & squashSmall Amphibians0.010.01Broadleaf Plants/Small Insects0.271 in 1.62E+06(1 in 50.03, 1 in 9.61E+13)0.161 in 1.16E+11(1 in 456.17, 1 in 7.08E+25)0.08Fruits/Pods/Seeds/Large Insects0.030.020.01Small Herbivore Mammals2.911 in 1.00(1 in 1.05, 1 in 1.00)0.341 in 2.67E+04(1 in 21.39, 1 in 4.65E+09)Small Insectivore Mammal0.181 in 6.42E+09(1 in 259.99, 1 in 5.91E+22)0.02EggplantSmall Amphibians0.010.003Broadleaf Plants/Small Insects0.331 in 5.56E+04(1 in 24.96, 1 in 2.73E+10)0.201 in 1.07E+09(1 in 183.02, 1 in 7.36E+20)0.10Fruits/Pods/Seeds/Large Insects0.040.020.01Ornamentals &shade treesSmall Herbivore Mammals3.531 in 1.00(1 in 1.02, 1 in 1.00)0.421 in 1.68E+03(1 in 11.78, 1 in 6.23E+06)160Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC,acutetoxicity data, and probitslope response relationships.Use CategoryDietary Category1.4 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI35 gHerp.AcuteRQ238 gChance of Individual Effect atChance of Individual Effect atHerp.RQ or LOC Based on ProbitRQ or LOC Based on ProbitAcuteSlope & Slope's 95% CISlope & Slope's 95% CIRQSmall Insectivore Mammal0.221 in 8.08E+07(1 in 109.79, 1 in 1.32E+18)0.03Small Amphibians0.010.003Broadleaf Plants/Small Insects0.761 in 6.26(1 in 2.97, 1 in 17.15)0.461 in 491.37(1 in 8.94, 1 in 3.37E+05)0.231 in 4.27E+07(1 in 96.71, 1 in 2.80E+17)Fruits/Pods/Seeds/Large Insects0.080.050.03Small Herbivore Mammals8.261 in 1.00(1 in 1.00, 1 in 1.00)0.971 in 2.18(1 in 2.07, 1 in 2.30)Small Insectivore Mammal0.521 in 135.66(1 in 6.63, 1 in 1.66E+04)0.06PotatoSmall Amphibians0.020.01Broadleaf Plants/Small Insects0.431 in 1.11E+03(1 in 10.74, 1 in 2.32E+06)0.261 in 3.46E+06(1 in 58.37, 1 in 6.10E+14)0.131 in 6.20E+13(1 in 1.53E+03, 1 in 3.63E+32)Fruits/Pods/Seeds/Large Insects0.050.030.01Small Herbivore Mammals4.651 in 1.00(1 in 1.01, 1 in 1.00)0.551 in 77.93(1 in 5.80, 1 in 4.59E+03)Small Insectivore Mammal0.291 in 3.99E+05(1 in 37.58, 1 in 3.22E+12)0.03Sweet potatoSmall Amphibians0.010.004Broadleaf Plants/Small Insects0.761 in 6.26(1 in 2.97, 1 in 17.15)0.461 in 491.37(1 in 8.94, 1 in 3.37E+05)0.231 in 4.27E+07(1 in 96.71, 1 in 2.80E+17)Fruits/Pods/Seeds/Large Insects0.080.050.03Small Herbivore Mammals8.261 in 1.00(1 in 1.00, 1 in 1.00)0.971 in 2.18(1 in 2.07, 1 in 2.30)Small Insectivore Mammal0.521 in 135.66(1 in 6.63, 1 in 1.66E+04)0.06Dry beans (exceptLima), peas &pepperSmall Amphibians0.020.01Broadleaf Plants/Small Insects0.541 in 91.07(1 in 6.03, 1 in 6.58E+03)0.321 in 6.52E+04(1 in 25.81, 1 in 4.01E+10)0.161 in 1.44E+11(1 in 475.86, 1 in 1.21E+26)Fruits/Pods/Seeds/Large Insects0.060.040.02Small Herbivore Mammals5.821 in 1.00(1 in 1.00, 1 in 1.00)0.681 in 12.41(1 in 3.62, 1 in 73.56)Small Insectivore Mammal0.361 in 1.06E+04 (1 in 17.58, 1 in5.08E+08)0.04CarrotSmall Amphibians0.010.01161162Table 5.13 Summary of the chance of individual acute effects to herpetofauna based on acute RQs, the acute listed species LOC,acutetoxicity data, and probitslope response relationships.Use CategoryDietary Category1.4 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI35 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CI238 gHerp.AcuteRQChance of Individual Effect atRQ or LOC Based on ProbitSlope & Slope's 95% CIBroadleaf Plants/Small Insects0.541 in 91.07(1 in 6.03, 1 in 6.58E+03)0.321 in 6.52E+04(1 in 25.81, 1 in 4.01E+10)0.161 in 1.44E+11(1 in 475.86, 1 in 1.21E+26)Fruits/Pods/Seeds/Large Insects0.060.040.02Small Herbivore Mammals5.821 in 1.00(1 in 1.00, 1 in 1.00)0.681 in 12.41(1 in 3.62, 1 in 73.56)Small Insectivore Mammal0.361 in 1.06E+04(1 in 17.58, 1 in 5.08E+08)0.04CelerySmall Amphibians0.010.01Broadleaf Plants/Small Insects0.581 in 46.81(1 in 5.12, 1 in 1.43E+03)0.351 in 2.11E+04(1 in 20.35, 1 in 2.65E+09)0.171 in 2.39E+10(1 in 336.03, 1 in 1.49E+24)Fruits/Pods/Seeds/Large Insects0.060.040.02Small Herbivore Mammals6.251 in 1.00(1 in 1.00, 1 in 1.00)0.741 in 7.82(1 in 3.17, 1 in 27.32)Small Insectivore Mammal0.391 in 3.84E+03(1 in 14.11, 1 in 4.44E+07)0.05StrawberrySmall Amphibians0.010.01Broadleaf Plants/Small Insects0.701 in 10.90(1 in 3.49, 1 in 55.57)0.421 in 1.49E+03(1 in 11.47, 1 in 4.68E+06)0.211 in 2.98E+08(1 in 142.18, 1 in 3.21E+19)Fruits/Pods/Seeds/Large Insects0.080.050.02Small Herbivore Mammals7.551 in 1.00(1 in 1.00, 1 in 1.00)0.891 in 3.03(1 in 2.35, 1 in 4.10)Small Insectivore Mammal0.471 in 360.53(1 in 8.33, 1 in 1.63E+05)0.06TomatoSmall Amphibians0.010.01(1)Bolded RQs exceed the Agency’s interim herpetofauna acute listed species LOC (0.1 ). When acute RQs exceed the Agency’s listedspecies LOC, the chance of individual effects was calculated at the RQ and the LOC,whereas if there was no exceedance, then the chance of individual effects was calculated only at the LOC.(2)Because birds are a surrogate for reptiles and terrestrial-phase amphibian, the probit slopes for birds was used. The probit slope for the bird acute LD50 was 8.5 with 95%confidence limits of 3.6 and 13.4. The probitslope for the insect was 1.91 with 95%confidence intervals of 1.40 and 2.42.(3)The 1.4 g size class wase used to represent small terrestrial phase CRLF; the 37 g size class was used to represent adult CTS and the 238 g size class was used to represent adult SFGS.

### 5.2.1 California Red-Legged Frog

5.2.1.1 Direct Effects

The characterization of the like lihood of direct effects on the CRLF from registered uses of endosulfan in California considers multiple lines of evidence. These lines of evidence include:

• The degree of temporal and spatial overlap between known CRLF habitat and
endosulfan use ( Appendix E ).

• Estimated risks from exposure modeling in aquatic and terrestrial ecosystems

• The likelihood of impacts to individual CRLF using probit dose-response modeling

• Estimated risks using monitoring data fr om aquatic and terrestrial ecosystems

• Use of refined exposure and risk estim ation methods (e.g., T- HERPS modeling for herpetofauna, earthworm fugacity modeling fo r contaminated terrestrial invertebrate prey, KABAM modeling for contaminated aquatic prey)

• Information from reported ecological inci dents associated with endosulfan use.

In addition to these lines of evidence, the robustness of the risk estimation described in Section 5.1 is also considered by characterizing the major uncertain ties and sensitivity of risk projections to underlying assump tions specific to the CRLF asse ssment. A discussion of each of these lines of evidence is pr esented in the following sections.

Direct Effects: Aquatic-Phase CRLF

The aquatic-phase considers life stages of th e CRLF that are obligatory aquatic organisms, including eggs and larvae. It also considers submerged terrestri al-phase juveniles and adults, which spend a portion of their time in water bodi es that may receive runoff and spray drift containing endosulfan.

Temporal and Spatial Overlap

Endosulfan is currently registered for a wide variety of agricu ltural crops (e.g., cotton, lettuce, brussels sprouts, cucurbits, dr y beans, cole crops), orchards (e.g., citrus, almonds, walnuts), nursery (ornamentals and shade tr ees) and only one non-agricultural us e (ear tags for cattle). These agriculture uses span a large variety of use sites and geogra phical regions throughout
the entire state of California. Historically, however, the use of endosulfan has changed substantially over the last decade, with overall use dropping from approximately 500,000 lbs a.i. in 1994 to about 90,000 lbs a.i. in 2006 ( Figure 2.3 ). Therefore, data from the most recent reporting years is used here for evalua ting the degree of temporal and spatial overlap
between the CRLF and endosulfan a pplication in California.

Based on data from the most recent reporting year (2006), the regist ered endosulfan uses allow for the potential for nearly year-round use, with the exception of little or no use during November, December and a portion of April (see Figure 5.1 ). Based on the likely occurrenceof aquatic life stages of the CRLF (eggs, tadpoles and young juveniles during JanuarySeptember; Figure 5.2 ) in combination with the CDPR PUR data from 2006 ( Figure 5.1 ), it

163

### is reasonably expected that the registered use of endosulfan could coincide with each of the critical life-stages of the aquatic-phase CRLF.

Time distribution for the total Lbs of endosulfan a.i applied during the year 2006

0 100 200 300 400 500 600

9-Jan 9-Feb 9-Mar 9-Apr 9-May 9-Jun 9-Jul 9-Aug 9-Sep 9-Oct 9-Nov 9-Dec

Date of ApplicationTotal Endosulfan a.i. Applied (lbs)

Figure 5.1 Temporal distribution of endosulfan application in California for 2006 (Source: CDPR PUR))

Young Juveniles
Tadpoles (except those that overwinter) Breeding/Egg Masses



### J F M A M J J A S O N D

Figure 5.2 CRLF Reproductive Events by Month; Adults and juveniles can be present all year.



### Table 5.7 summarizes information on the extent that endosulfan use and CRLF could potentially coincide spatially based on reported use information from 2005-2006 (CDPR PUR) and information on the occurrence of the CRLF or its critical habitat ( Appendix E ). Since pesticide use information is only availabl e at the county level, the degree that the CRLF
or its critical habitat ac tually coincides in the same or similar locations cannot be precisely determined. Nevertheless, there does appear to be a significant potential for overlap between the use of endosulfan and the pres ence of the CRLF or its critical habitat at least at the county level of resolution ( Appendix E ). Specifically, the CRLF is pres ent in counties with the first,

164

### fourth, fifth, tenth and eleventh hi ghest reported usage from 2005-2006 ( Table 5.7 ). The CRLF is also present in most other coun ties with lower endosulfan reported use.

Modeling--Based EECs

Acute RQs based on modeled EECs for freshwater fish (used as a surrogate for the aquatic phase CRLF) range from 7.2 to 58.8, thus exceed ing the Agency’s LOC (0.05) in all 20 crop scenarios modeled ( Table 5.1 ). Similarly, chronic RQs range from 5.7 to 80.6 and exceed the Agency’s LOC (1.0) in all 20 crop scen arios modeled. These exceedences of the Agency’s acute and chronic LOCs suggest th e potential for direct effects on the CRLF.

As previously mentioned, EFED also estim ates the chance of an individual event ( i.e

., mortality or immobilization) corresponding to the listed species acute LOCs and/or RQs should exposure at the EEC actually occur for a species with sensitivity to endosulfan on par with the acute toxicity endpoint selected for RQ calculation. To do this, the Agency uses the EFED spreadsheet IEC (version 1.1.xls) and th e slope of the dose response relationship available from the toxicity study used to establ ish the acute toxicity m easures of effect for each taxonomic group that is relevant to this a ssessment. The individual effects probability associated with the listed species acute LOCs a nd/or RQs 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, availabl e information on the 95% confidence interval of the slope is also used to estimate upper a nd lower estimates of the effects probability to account for variance in the slope , if available. If an LD 50 

### or LC 50 

### has been established for a particular taxonomic group, but information is unavailable to estimate a slope from a study, a default slope assumption of 4.5 (with upper and lo wer bounds of 2 and 9, respectively) is used as per original Agency assumptions of typi cal slope cited in Urba n and Cook (1986).

Based on a default slope of 4.5 (with uppe r and lower bounds of 2 and 9), the LC 50 

### of the most acutely sensitive freshw ater fish (common carp; LC 50 

### = 0.1 μg a.i./L; Sunderam et al., 1992; ECOTOX ref. # 5850) and the acute liste d species LOC of 0.05, the chance of an individual mortality for aqua tic-phase CRLF is ~ 1 in 4.18 x10 8 

### (with lower and upper bounds
of ~ 1 in 2.16 x10 2 

### to ~ 1 in 1.75x10 31 

### ; Table 5.11 ). Based on an analysis of the likelihood of individual mortality using the highest acute RQ value for freshwater fish (RQ=58.8 for Lettuce and Brussels Sprouts) and a default slope of 4.5 (with upper and lower bounds of 2 and 9), the likelihood of individua l mortality is ~ 1 in 1 (with lower and upper bounds of ~ 1 in 1.00 to 1 in 1.00). At the lowest RQ value ( i.e. , RQ = 7.2 for Eggplant), the likelihood of individual mortality is ~ 1 in 1.00(with lower and upper bounds of ~ 1 in 1.00 to ~ 1 in 1.05).

Based on: (1) the high probability of an individual mortality occurrence using the highest acute RQ (~1 in 1), (2) acute RQs that are above the listed specie s LOC (0.05) for all 20 modeled scenarios; (3) chronic RQs that ex ceed the Agency’s LOC for all 20 modeled scenarios (1.0). and (4) the potential for spatia l and temporal overlap of endosulfan usage with each of the critical life-stages of the aquatic-phase CRLF, it appears that endosulfan is likely
to cause direct adverse effect s to aquatic-phase CRLFs should exposure at the predicted EECs actually occur for a CRLF and assuming its sensitivity to endosulfan on par with the acute
freshwater fish LC 50 

### (common carp; LC 50 

### = 0.1 μg a.i./L) selected for RQ calculation.

165

### Monitoring-based EECs

Available data on the occurrence of endosulfan (a nd its primary degradate, endosulfan sulfate)
in surface water were evaluated as another line of evidence for potential risks to aquatic-phase
CRLF. As described in Section 3.2.4.1 , surface water data were compiled from three sources: CDPR, EPA’s STORET database, and the USGS NAWQA. As an approximate screen of these data, maximum detected values for total endosulfan were used to calculate acute and chronic RQs for freshwater fish (used as a surrogate for aquatic-phase CRLF; Table 5.14 ).
As described in Section 3.2.4.1 , available surface water monitori ng data indicate a substantial
reduction in endosulfan concentrations after 2001 as compared to the early to mid 1990’s. Based on this comparison, acute and chronic RQ s based on maximum reported concentrations range from 9.5 to 41.3, respectively, in the 1991-1996 sampling period but drop to 0.05-0.08 and 0.22-0.35, respectively, during the 2001-2008 sampling period. Acute RQs based on maximum detected concentrations during the 2001 time periods still exceed the Agency’s LOC of 0.05 for listed species, but are much lower than in the 1990s. Chronic RQs based on maximum detected during the 2001-2008 sampling period do not exceed the Agency’s
chronic listed LOC of 1.0.

Several caveats should be considered when in terpreting the monitoring data summarized in
Table 5.14 and in Section 3.2.1.4 . First, these data do not repr esent targeted monitoring data that are designed to capture peak concentrations of pesticides in surf ace waters. Therefore, these data likely underestimate peak concentratio ns of endosulfan and are likely not directly comparable to modeling-based peak EECs. Second, the NAWQA data included limits of
detection that exceeded the c oncentration correspondi ng to the Agency listed acute LOC of 0.05 (i.e., 0.005 ug/L) and therefore are of limited value for estimating the potential for direct effects to the CRLF. Despite these limitations , the available monitori ng data during the most recent sampling period for endosulfan in Calif ornia surface waters (2001-2008) does suggest a potential for acute risk to aquatic-phase CRLF assuming their acute sensitivity is comparable to the most sensitive freshwater fish tested.

Table 5.14 Comparison of maximum detected concentrations of total endosulfan in su rface waters of California to Agency LOC for freshwater fish



### Data Source (1) 

### Sampling
Period Total
Number of

Samples Maximum
Value Detected (ug/L) FW Fish Acute RQ (3) 

### FW Fish Chronic RQ (4)



### CDPR 1991-96 ~ 2000 0.95 9.5 41.3
2001-06 580 0.005 0.05 0.22
STORET 2001-08 304 0.008 0.08 0.35 NAQWA 1995; 01-07 204 ND (2)



### --- --- (1) See Section 3.2.4.1 for a description of data sources.
(2) Limit of detection typically ranged from 0.01 to 0.02 ug/L for α - and β -endosulfan and/or endosulfan sulfate, which exceeded concentrations corresp onding to the acute LOC (0.005 ug/L).
(3) RQ based on LC 50 for freshwater fish (0.1 ug/L; Sunderam et al, 1992; ECOTOX 5850), which are used as a surrogate for aquatic-phase amphibians. Bold values indicate equivalence or exceedence of Agency’s acute listed
LOC of 0.05.
(4) RQ is based on a NOAEC for freshwater fish of 0.023 ug/L (estimated using an acute-chronic ratio of 4.3 for fathead minnow; see Table 4.1 ). Bold values indicate exceedence of Agency’s chronic listed LOC of 1.0.



### 166

### Species Sensitivity Analysis

As indicate above, acute toxic ity data for the most sensitive species of freshwater fish (common carp, LC 50 

### = 0.1 μg a.i./L) is being used to re present the sensitivity of the aquatic phase CRLF due to the absence of acceptable toxi city data for amphibians. To evaluate the potential uncertainty of the risk estimation wi th respect to using the most sensitive fish species, the sensitivity of the common carp is put into context of available data for all tested freshwater fish ( Figure 5.3 ). In this figure, th e geometric mean of LC 50 

### values for each species of freshwater fish from both studies submitted to the Agency and those available in ECOTOX are provided in the form of a species sensitivity distribution. Geometric mean of
LC 50 

### values for each species are indicated by a so lid circle . Notably, the ECOTOX data that were greater than the initial acute toxicity benchmark of 0.8 3 μg/L were not evaluated beyond
the initial OPP data screen described in Sect ion 4. The thick blue line designates the LC 50 

### value used in the RQ calculation (0.1 μg/L). The vertical blue lines represent the range of predicted peak EECs from the 20 crop expos ure scenarios modeled (i.e., 0.72 ug/L for Eggplant and 5.88 ug/L for Lettuce and Brussels sp routs scenarios). Th e vertical red lines indicate the range of the p eak EECs (0.72 and 5.88 μg/L) divided by the acute listed species
LOC of 0.05.

Freshwater Fish

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

0.10 1.00 10.00 100.00 1000.00

LC50 (μg/L)Fractional Rank

benchmarklowest EEC/LOChighest EEC/LOClowest EEChighest EEC

Figure 5.3 Species sensitivity distribution of the acute toxicity of endosulfan to freshwater fish



### Based on the range of modeled peak EECs of 0.72 to 5.88 ug/L determined in Section 3 (see
Table 5.1 ), the proportion of species affected would range from approximately the 15 th 

### to the
70 th 

### percentiles of the observed species sensitivity distribut ion blue lines on Figure 5.3 ).

167

### Taking into account the acute liste d LOC of 0.05, the assumed acute sensitivity of freshwater
fish would have to be near above the least se nsitive species tested in order for the modeled EECs (0.72 – 5.88 ug/L) to not exceed the agency LOC. Therefore, this analysis indicates that within the context of the sensitivity of freshwater fish, RQ exceedences of the LOC of
0.05 are not sensitive to the sele ction of the most acutely sens itive fish species tested (i.e.,
LOC exceedences would occur even the more acute ly insensitive species was selected for RQ calculation).

While the previous discussion address sensitivity differences within the context of freshwater fish, it does not address potential differences in sensitivity between freshwater fish and aquatic-phase amphibians. Although no data we re found in the open literature that were considered acceptable for quantitativ e use in this risk assessment, data were found that can be used qualitatively for describing the general sensitivity of aquatic- phase amphibians. The lowest LC50 in the open literature for endosul fan using amphibians was 0.16 μg a.i./L for tadpoles of Micorohyla ornate (see Section 4.1.5 ), based on unmeasured values. This species of amphibian is much smaller than CRLF (22- 23 mm snout-vent length for adults—Geng et al. 2005). Adults of CRLF range from 85-138 mm SVL (see Attachment 3 ). It is reasonable
to assume that smaller animals would be more susceptible to the same toxicant exposure than larger ones. However, even if the CRLF has the same acute sensitivity as M. orgata , the freshwater fish acute benchmark (LC50 = 0.1 μg a.i./L) should still be protective of the aquatic-phase of CRLF. The lo west endosulfan effect con centration for longer exposure durations ( Rana pipiens —for 7 weeks) suggested a 49 da LC50 of 0.2 μg a.i./L (estimated from Shenoy et al., in press). Again, if we assu me that the CRLF had this same sensitivity, the freshwater chronic benchmark (0.023 μg a.i./L) would likely be protective. At an LC50 of 0.2 μg a.i./L and the default probit slope of 4.5, the expected mortality at 0.023 μg a.i./L would be
close to 0%.

Consumption of Contaminated Aquatic Prey

Freshwater fish and aquatic i nvertebrates are a documented co mponent of the diet of the aquatic-phase CRLF. For persiste nt organic chemicals with log K OW 

### values that exceed 4, evidence from empirical and mode ling studies indicates that bi omagnification in aquatic food webs can significantly increase exposure to or ganisms feeding on top trophic level aquatic prey (USEPA, 2000; 2003; 2008; Fisk et al., 1998). Log K OW 

### values for α -endosulfan have been reported from 3.55 to 4.74 (McConnell et al 1998; MRID 414215-01, respectively). Log

K OW 

### values for β -endosulfan have been reported from 3.62 to 4.79 (McConnell et al 1998; MRID 414215-01, respectively). A log K OW 

### value of 3.71 has been reported for endosulfan sulfate ( Table 2.1 ).

Considering that log K OW 

### values for the parent endosulfan isomers and endosulfan sulfate either approach or exceed a log Kow of 4, a nd that endosulfan can persist for relatively long periods of time in aquatic ecosystems, the poten tial for direct effects on aquatic-phase CRLF through consumption of contaminated aquatic prey was investigated. The KABAM model (K OW 

### (based) Aquatic BioAccumulation Model) vers ion 1.0 was used to evaluate the potential exposure and risk of direct effects to aquatic-phase CRLF via bioaccumulation and biomagnification in aquatic food webs. KABAM is used to estimate potential

168

### bioaccumulation of hydrophobic organic pesticides in freshwater aquatic ecosystems and risks to mammals and birds consuming aquatic or ganisms which have bioaccumulated these pesticides. The bioaccumulation portion of KABAM is based upon work by Arnot and Gobas (2004) who parameterized a bioaccumulation mode l based on PCBs and some pesticides (e.g., lindane, DDT) in freshwater aquatic ecosystem s. KABAM relies on a chemical's octanolwater partition coefficient (K OW 

### ) to estimate uptake and elim ination constants through respiration and diet of organisms in different trophic levels. Pesticide tissue residues are calculated for different levels of an aquatic food web. The model then uses pesticide tissue concentrations in aquatic animals to estim ate dose- and dietary-based exposures and associated risks to mammals and birds consuming aquatic organisms. Previous analyses using
an earlier version of the KAB AM model indicate relatively close agreement between its predicted bioconcentration factor (BCF) and t hose reported from experimental studies for endosulfan (2007; D346213).

For the aquatic-phase CRLF analysis, the ecosystem components for avian consumers were modeled, as birds are considered surrogates fo r aquatic-phase amphibians. However, the default avian species used in KABAM were al tered to more accurately represent the size range and dietary preferences of the CRLF. Sp ecifically, three size classes were modeled (1.4g, 37g, and 238g) each with a different dietary composition that would be representative of its body size and likel y feeding pattern ( Table 5.15 ). For each of these size classes, two different dietary preferences were selected to bound the range of trophic levels at which the CRLF could potentially feed.

Table 5.15 Assumed dietary preferences of sm all (1.4g), medium (37g) and large (238g) CRLF feeding on aquatic biota of the model ecosystem.

Diet for: Trophic level in
diet small CRLF
1 small CRLF 2 Med CRLF 1 med CRLF 2 large CRLF 1 large CRLF 2 phytoplankton 100.0% 0.0% 0.0% 0.0% 0.0% 0.0% Zooplankton 0.0% 0.0% 0. 0% 0.0% 0.0% 0.0%

Benthic
invertebrates 0.0% 100.0% 100.0% 0.0% 100.0% 0.0%

filter feeders 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

small fish 0.0% 0.0% 0.0% 100.0% 0.0% 0.0%

Medium fish 0.0% 0.0% 0.0% 0.0% 0.0% 100.0% large fish 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%



### Other chemical and ecosystem-specific parame ters selected for the KABAM analysis are
summarized in Table 5.16 and in Appendix I

.

Table 5.16 Endosulfan chemical char acteristics used as input to KABAM

Characteristic Value Source/Comments Log K OW 4.76 Weighted mean of Kow for alpha and beta endosulfan based on TGAI (70:30 alpha:beta). MRID 414215-01



### 169K OC (L/kg OC) 10,600 Average value for alph a endosulfan used in PRZM/EXAMS modeling (Table 3.3)

Estimated time to steady state (T S ; days) 18 This value is calculated automatically from the Log K OW value and is used to select the appropriate averaging period for the surface water and pore water EEC
Surface water EEC (μg/L) 0.24-2.60 Range of 21-d surfac e water EECs for total endosulfan (alpha, beta, sulfate) predicted using PRZM/EXAM modeling ( Table 3.5 ). Results from each of the 20 crop scenarios were modeled separately.

Pore Water EEC (μg/L) 0.09-1.18 Range of 21-d pore water EECs for total endosulfan (alpha, beta, sulfate) predicted using PRZM/EXAM modeling ( Table
3.7 ). Results from each of the 20 crop scenarios were modeled separately.



### Concentrations in aquatic prey predicted us ing KABAM for the two crop scenarios yielding the lowest and highest 21-d average surf ace and pore water EECs (Eggplant and Broccoli, Cabbage & Cauliflower, respectively) are summarized in Table 5.17

. Calculation of dose and dietary-based EECs for these scenarios are provided in Table 5.18 and the resulting RQ
values are summarized in Table 5.19

. For the scenario yielding the largest surface water and pore water EECs (Broccoli, Cabbage & Cauliflo wer), acute, dose-based RQs range from 0.14 to 4.0, thus exceeding the acute listed LOC of 0.1 for all six CRLF size class/feeding preference combinations. Acut e and chronic, dietary-based RQs do not exceed the Agency LOCs for the Broccoli, Cabbage & Cauliflower exposure scenario. For the scenario yielding the smallest surface water and pore water EEC s (Eggplant), acute, dose-based RQs range
from 0.01 to 0.37 and exceed the acute listed LOC of 0.1 for two of the six CRLF size class/feeding preference combinations. Results from aquatic bioaccumulation modeling for all 20 crop exposure scenarios are summarized in Appendix I

.

Based on these results, it appears that there is a potential for direct effects on aquatic-phase CRLF due to the consumption of aquatic prey contaminated with endosulfan, assuming similar sensitivity to the most sensitive av ian species tested a nd surface water exposure profiles predicted by PRZM/EXAMS.

Table 5.17 Estimated concentratio ns of endosulfan in ecosystem components for two crop exposure
scenarios

Eggplant (1) Broccoli, Cabbage & Cauliflower (1)

Ecosystem Component Total
concentration

(μg/kg-ww) Lipid
normalized
concentration

(μg/kg-lipid) Total
concentration

(μg/kg-ww) Lipid
normalized
concentration

(μg/kg-lipid) Water (total)* 0.237 N/A 2.603 N/A Water (freely dissolved)* 0.237 N/A 2.603 N/A Sediment (pore water)* 0.090 N/A 1.181 N/A Sediment (in solid)** 38 N/A 501 N/A Phytoplankton 622 31,082 6,828 341,376 Zooplankton 468 15,606 5,142 171,405



### 170Benthic Invertebrates 504 16,808 5,560 185,325

Filter Feeders 333 16,633 3,668 183,403
Small Fish 697 17,432 7,686 192,149

Medium Fish 762 19,047 8,400 209,990 Large Fish 916 22,904 10,075 251,880 * Units: μg/L; **Units: μg/kg-dw (1) Total concentrations in aquatic organisms calc ulated using KABAM v.1.0. Lipid normalized concentrations based on lipid fractions of 2% for phytoplankton and f ilter feeders, 3% for zooplankton and benthic macroinvertebrates, and 4% for small, medium and large fish.

Table 5.18 Calculation of EECs for CRLF consum ing aquatic prey contaminated by endosulfan Biological Parameters EECs (pesticide intake) (1)

Dose Based (mg/kg-bw/d) Dietary Based (ppm) Wildlife Species Body Weight (kg) Dry Food Ingestion
Rate (kg-dryfood/kgbw/day) Wet Food Ingestion
Rate (kg-wetfood/kgbw/day) Drinking
Water
Intake (L/d) Eggplant Broccoli, Cabbage & Cauliflower Eggplant Broccoli, Cabbage & Cauliflower

Small CRLF 1 0.0014 0.577 5.767 0.001 3.585 39.37 0.62 6.83

Small CRLF 2 0.0014 0.577 2.403 0.001 1.212 13.36 0.50 5.56

Med CRLF 1 0.037 0.184 0.766 0.006 0.386 4.261 0.50 5.56

Med CRLF 2 0.037 0.184 0.681 0.006 0.475 5.236 0.70 7.69

Large CRLF 1 0.238 0.096 0.400 0.023 0.202 2.225 0.50 5.56

Large CRLF 2 0.238 0.096 0.356 0.023 0.271 2.988 0.76 8.40

(1) EECs calculated using KABAM v. 1.0 using dietary prefer ences for the small (1.4g), medium (37g) and large (238g) CRLF in Table 5.17 and predicted concentrations in aquatic prey from Table 5.19.

Table 5.19 Calculation of RQ values for CRLF cons uming aquatic prey contaminated by endosulfan.

Acute Chronic Wildlife Species

Dose Based (1) Dietary Based (2) Dietary Based (3)

Broccoli, Cabbage & Cauliflower

small CRLF 1 4.036 0.008 0.228

small CRLF 2 1.369 0.007 0.185

med CRLF 1 0.267 0.007 0.185

med CRLF 2 0.328 0.010 0.256

large CRLF 1 0.106 0.007 0.185



### 171Table 5.19 Calculation of RQ values for CRLF cons uming aquatic prey contaminated by endosulfan.

Acute Chronic Wildlife Species

Dose Based (1) Dietary Based (2) Dietary Based (3)

large CRLF 2 0.142 0.010 0.280

Eggplant
small CRLF 1 0.367 0.001 0.021

small CRLF 2 0.124 0.001 0.017

med CRLF 1 0.024 0.001 0.017

med CRLF 2 0.030 0.001 0.023

large CRLF 1 0.010 0.001 0.017

large CRLF 2 0.013 0.001 0.025

(1) Acute dose-based RQs calculated using the dose-based EECs from Table 5.20 and adjusted, acute dose-based toxicity values of 9.76, 15.94, and 21.08 mg/kg-bw for the 1.4g, 37g, and 238g CRLF, respectively. Unadjusted LD50 = 28 mg/kg-bw based on mallard duck (MRID 136998 ). (2) Acute diet-based RQs calculated using diet-based EECs from Table 5.20 and a diet-based LC50 of 805 ppm for bobwhite quail (MRID 22923 ) (3) Chronic diet-based RQs calculated using the dietary EECs and an avian dietary NOAEC of 30 ppm for mallard duck (MRID 40335001)



### Ecological Incident Reports

As summarized in Section 4.4 and Appendix L , the vast majority of the 83 aquatic incident reports associated with endosulfa n involved mortality to fish (67) . A wide variety of fresh and estuarine species were reportedly affected (e.g., carp, catfish, largemouth bass, shad, menhaden, mullet, spot, bluegill sunfish, gar and trout). These incident reports support the findings from laboratory toxicity studies that fish are a highly sensitive taxonomic group to endosulfan exposure. Of the 67 aquatic incide nts involving fish, 53 (80 %) are classified as either ‘highly probable’ or ‘pr obable’ in the context of endosul fan use. Of all the incident reports classified as highly probable or probable, about 15 (25%) are associated with a ‘registered use’ (most are accidental misuse or of unknown causes). Of those associated with ‘registered uses,’ most described pesticide r unoff following periods of heavy rainfall as the likely event that led to the reported incident. No incidents were reported for aquatic-phase amphibians. As noted in Appendix L, there ar e a number of uncertainties associated with incident reports, including a lik ely underreporting of actual ecological incidents that occur and uncertainty associated with attributing causal ity. Nevertheless, the information available in from the incident reports are not inconsistent with the resu lts from the modeling-based RQs that suggest risks to freshwater fish (and by extension, the aquatic-phase CRLF) can exceed Agency LOC.

172

### Direct Effects: Terrestrial-Phase CRLF

T-REX and T-HERPS Modeling

As described in Section 5.1 , risks to terrestrial-phase CRLF were estimated using birds as a surrogate using the Agency’s T-REX model. ( Table 5.3 ) Risk quotients from the “broadleaf plants/small insect” and “fruits /pods/seeds/large insect” categor ies were chosen for assessing risks to terrestrial pha se CRLF because it consumes terrestr ial invertebrates and other prey types were not represented in T-REX. Th e dose-based acute RQs calculated for 20g birds consuming small and large insects exceed the Agency acute listed LOC (0.1) in all 20 crop scenarios modeled (range: 5.3 to 26.4 for small insects; 0.6 to 2.9 for large insects, respectively). The acute diet-based RQs exceed the Agency’s acute listed LOC in 19 of the
20 scenarios modeled for small insects but none of the 20 scenarios modeled for large insects (range: 0.08 to 0.42 for small insects; 0.01 to 0.05 for large insects). Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively. Chronic RQs range fr om 2.3 to 11.3 for the small insect category and 0.3 to 1.3 for the large ins ect dietary category.

Direct effects on listed reptiles and terrestrial-phase amphibian s were evaluated in the same manner as above for birds except T-HERPS wa s used instead of T-REX. The model THERPS is a modified form of T-REX, which is designed to be more reflective of the food requirements of amphibians (including consump tion of small herbivorous and insectivorous mammals and small amphibians) and allow for an estimation of food intake for poikilotherms using the same basic procedure as T-REX. This involves adjusting daily food intake with an
allometric model that accounts for the lower food intake of poikilo thermic reptiles and amphibians. The net effect of this approach is a reduction in pest icide exposure due to reduced food consumption.

The same bird acute datum (LD50=28 mg/kg b.w. for mallard duck) was used; however, the adjusted LD50s for the different size classes were different. These were 9.76 mg/kg b.w. for small (1.4 g), 15.94 mg/kg b.w. for medium (37 g) and 21.08 for large (238 g) herpetofauna, and were calculated by T-HERPS. All three size cl asses are used to evaluate the potential for
direct acute effects on CRLF. Based on the mode led acute dose-based EECs for various use scenarios and diet categories and the above acute toxic ity data, the RQs for small herpetofauna ranged from 0.03 to 1.34, with 24 of the 40 modeled scenarios resulting in exceedences of the Agency’s acute listed species LOC (>0.1). Based on the modeled acute
dose-based EECs for various use scenarios and di et categories and the above acute toxicity data, the RQs for medium herpetofauna ranged from 0.006 to 14.55 with 60 of the 100 modeled scenarios resulting in exceedences of the Agency’s acute listed species LOC (>0.1). The acute dose-based RQs for large herpetof auna range from 0.003 to 1.71 with 41 of the 100 modeled scenarios exceeding the Agency’s LO C (>0.1). The acute dietary-based RQs ranged from 0.003 to 0.71, and 39 of the 100 scenarios resulted in RQs that exceeded the agency’s LOC (>0.1). Finally, the chronic dietary-based RQs for herpetofauna ranged from 0.078 to 19.07 with 46 of these values exceeding the LOC for listed species (>1) (see Table 5.20 ).

Based on exceedences of the Agency’s acute risk LOC (RQ>0.1) and chronic risk LOC (RQ>1), it is concluded that endosulfan has th e potential to directly affect reptiles and

173

### terrestrial-phase amphibians (i.e., CRLF, CTS and SFGS) during at least some portion of their life-history.

Table 5.20 Summary of the acute and chronic dose- and dietary-based RQs for herpetofauna estimated
based on the maximum endosulf an foliar spray applications using T-HERPS version 1.0.

Run Acute Dose Based Sub
AcuteDietaryChronicDietaryUse Category No. Dietary Category 1.4 g 37 g 238 g Based Based

Broadleaf Plants/Small Insects 1.08 0.65 0.32 0.34 9.00

Fruits/Pods/Seeds/Large Insects 0.12 0.07 0.04 0.04 1.00

Small Herbivore Mammals 11.64 1.37 0.57 15.25

Small Insectivore Mammal 0.73 0.09 0.04 0.95 Almonds,
hazelnut & walnut 1

Small Amphibians 0.02 0.01 0.01 0.31

Broadleaf Plants/Small Insects 1.34 0.81 0.40 0.42 11.25

Fruits/Pods/Seeds/Large Insects 0.15 0.09 0.04 0.05 1.25

Small Herbivore Mammals 14.55 1.71 0.71 19.07

Small Insectivore Mammal 0.91 0.11 0.04 1.19 Citrus 1

Small Amphibians 0.03 0.01 0.01 0.39

Broadleaf Plants/Small Insects 0.70 0.42 0.21 0.22 5.84

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.02 0.02 0.65

Small Herbivore Mammals 7.55 0.89 0.37 9.90

Small Insectivore Mammal 0.47 0.06 0.02 0.62 Broccoli, cabbage, Chinese cabbage, cauliflower,
kohlrabi 1

Small Amphibians 0.01 0.01 0.01 0.20

Broadleaf Plants/Small Insects 0.40 0.24 0.12 0.13 3.38

Fruits/Pods/Seeds/Large Insects 0.04 0.03 0.01 0.01 0.38

Small Herbivore Mammals 4.36 0.51 0.21 5.72

Small Insectivore Mammal 0.27 0.03 0.01 0.36 Kale, Collards & Mustard Green 2

Small Amphibians 0.01 0.004 0.004 0.12

Broadleaf Plants/Small Insects 0.81 0.48 0.24 0.25 6.75

Fruits/Pods/Seeds/Large Insects 0.09 0.05 0.03 0.03 0.75

Small Herbivore Mammals 8.73 1.03 0.43 11.44

Small Insectivore Mammal 0.55 0.06 0.03 0.72 Sweet corn 1

Small Amphibians 0.02 0.01 0.01 0.23

Broadleaf Plants/Small Insects 0.54 0.32 0.16 0.17 4.50

Fruits/Pods/Seeds/Large Insects 0.06 0.04 0.02 0.02 0.50

Small Herbivore Mammals 5.82 0.68 0.28 7.63

Small Insectivore Mammal 0.36 0.04 0.02 0.48 Cotton (ground) 1

Small Amphibians 0.01 0.01 0.01 0.16

Broadleaf Plants/Small Insects 0.52 0.31 0.16 0.16 4.38

Fruits/Pods/Seeds/Large Insects 0.06 0.03 0.02 0.02 0.49

Small Herbivore Mammals 5.66 0.67 0.28 7.42 Cotton (Areal) 3

Small Insectivore Mammal 0.35 0.04 0.02 0.46



### 174Table 5.20 Summary of the acute and chronic dose- and dietary-based RQs for herpetofauna estimated
based on the maximum endosulf an foliar spray applications using T-HERPS version 1.0.

Run Sub

Acute Dose Based Acute Chronic Dietary- DietaryUse Category No. Dietary Category 1.4 g 37 g 238 g Based Based

Small Amphibians 0.01 0.01 0.01 0.15

Broadleaf Plants/Small Insects 1.34 0.81 0.40 0.42 11.25

Fruits/Pods/Seeds/Large Insects 0.15 0.09 0.04 0.05 1.25

Small Herbivore Mammals 14.55 1.71 0.71 19.07

Small Insectivore Mammal 0.91 0.11 0.04 1.19 Apples 1

Small Amphibians 0.03 0.01 0.01 0.39

Broadleaf Plants/Small Insects 1.34 0.81 0.40 0.42 11.25

Fruits/Pods/Seeds/Large Insects 0.15 0.09 0.04 0.05 1.25

Small Herbivore Mammals 14.55 1.71 0.71 19.07

Small Insectivore Mammal 0.91 0.11 0.04 1.19 Apricot, nectarine, peach, cherry, pear, plum & prune 1

Small Amphibians 0.03 0.01 0.01 0.39

Broadleaf Plants/Small Insects 0.76 0.46 0.23 0.24 6.39

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.03 0.03 0.71

Small Herbivore Mammals 8.26 0.97 0.40 10.83

Small Insectivore Mammal 0.52 0.06 0.03 0.68 Lettuce & Brussels sprouts 1

Small Amphibians 0.02 0.01 0.01 0.22

Broadleaf Plants/Small Insects 0.70 0.42 0.21 0.22 5.84

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.02 0.02 0.65

Small Herbivore Mammals 7.55 0.89 0.37 9.90

Small Insectivore Mammal 0.47 0.06 0.02 0.62 Cucumber, melons, pumpkin & squash 1

Small Amphibians 0.01 0.01 0.01 0.20

Broadleaf Plants/Small Insects 0.27 0.16 0.08 0.08 2.25

Fruits/Pods/Seeds/Large Insects 0.03 0.02 0.01 0.01 0.25

Small Herbivore Mammals 2.91 0.34 0.14 3.81

Small Insectivore Mammal 0.18 0.02 0.01 0.24 Eggplant 3

Small Amphibians 0.01 0.003 0.003 0.08

Broadleaf Plants/Small Insects 0.33 0.20 0.10 0.10 2.73

Fruits/Pods/Seeds/Large Insects 0.04 0.02 0.01 0.01 0.30

Small Herbivore Mammals 3.53 0.42 0.17 4.63

Small Insectivore Mammal 0.22 0.03 0.01 0.29 Ornamentals &
shade trees 1

Small Amphibians 0.01 0.003 0.004 0.09

Broadleaf Plants/Small Insects 0.76 0.46 0.23 0.24 6.39

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.03 0.03 0.71

Small Herbivore Mammals 8.26 0.97 0.40 10.83

Small Insectivore Mammal 0.52 0.06 0.03 0.68 Potato 1

Small Amphibians 0.02 0.01 0.01 0.22



### 175Table 5.20 Summary of the acute and chronic dose- and dietary-based RQs for herpetofauna estimated
based on the maximum endosulf an foliar spray applications using T-HERPS version 1.0.

Run Sub

Acute Dose Based Acute Chronic Dietary- DietaryUse Category No. Dietary Category 1.4 g 37 g 238 g Based Based

Broadleaf Plants/Small Insects 0.43 0.26 0.13 0.13 3.59

Fruits/Pods/Seeds/Large Insects 0.05 0.03 0.01 0.01 0.40

Small Herbivore Mammals 4.65 0.55 0.23 6.09

Small Insectivore Mammal 0.29 0.03 0.01 0.38 Sweet potato 3

Small Amphibians 0.01 0.004 0.005 0.12

Broadleaf Plants/Small Insects 0.76 0.46 0.23 0.24 6.39

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.03 0.03 0.71

Small Herbivore Mammals 8.26 0.97 0.40 10.83

Small Insectivore Mammal 0.52 0.06 0.03 0.68 Dry beans (except Lima), peas & pepper 1

Small Amphibians 0.02 0.01 0.01 0.22

Broadleaf Plants/Small Insects 0.54 0.32 0.16 0.17 4.50

Fruits/Pods/Seeds/Large Insects 0.06 0.04 0.02 0.02 0.50

Small Herbivore Mammals 5.82 0.68 0.28 7.63

Small Insectivore Mammal 0.36 0.04 0.02 0.48 Carrot 2

Small Amphibians 0.01 0.01 0.01 0.16

Broadleaf Plants/Small Insects 0.54 0.32 0.16 0.17 4.50

Fruits/Pods/Seeds/Large Insects 0.06 0.04 0.02 0.02 0.50

Small Herbivore Mammals 5.82 0.68 0.28 7.63

Small Insectivore Mammal 0.36 0.04 0.02 0.48 Celery 2

Small Amphibians 0.01 0.01 0.01 0.16

Broadleaf Plants/Small Insects 0.58 0.35 0.17 0.18 4.83

Fruits/Pods/Seeds/Large Insects 0.06 0.04 0.02 0.02 0.54

Small Herbivore Mammals 6.25 0.74 0.31 8.19

Small Insectivore Mammal 0.39 0.05 0.02 0.51 Strawberry 2

Small Amphibians 0.01 0.01 0.01 0.17

Broadleaf Plants/Small Insects 0.70 0.42 0.21 0.22 5.84

Fruits/Pods/Seeds/Large Insects 0.08 0.05 0.02 0.02 0.65

Small Herbivore Mammals 7.55 0.89 0.37 9.90

Small Insectivore Mammal 0.47 0.06 0.02 0.62 Tomato 1

Small Amphibians 0.01 0.01 0.01 0.20

(2 ) RQ values in bold indicate exceedence of listed species acute LOC (0.1) and chr onic LOC (1.0). Acute dose-base RQs were based on dose-based EECs divided by adjusted avian acute LC50s (9.76 mg/kg b.w. for small; 15.94 mg/kg b.w. for medium; and 21.08 mg/kg b.w. for large).



### 176

### Likelihood of Effects

Based on an observed slope of 8.5 (with upper and lower bounds of 3.6 and 13.4, respectively), the corresponding LD 50 

### of the most sensitive avian species tested (mallard duck; MRID 136998), and the acute listed species LOC of 0.1, th e chance of an individual mortality for terrestrial-phase CRLF is ~ 1 in 1.05 x10 17 

### (with upper and lower bounds of ~ 1
in 6.29 x10 3 

### to ~ 1 in 3.31 x10 40 

### , respectively, Table 5.13 ). Using T-HERPS which considers the feeding preferences and bi oenergetics of amphibians and the observed slope described previously, the likelihood of individual mort ality to small (1.4g) CRLF using the highest acute RQ value (RQ=1.34 for Citrus) is ~ 1 in 1.16 (with lower and upper bounds of ~ 1 in 1.47 to 1 in 1.04, respectively). For medium size CRLF (37g), the lik elihood of individual mortality for the highest acute RQ (RQ=14.55 fo r Citrus) is ~ 1 in 1.00 (with lower and upper bounds of ~ 1 in 1.00 to ~ 1 in 1.00). Finally, for large size CRLF (238g), the likelihood of individual mortality for the highest acute RQ (RQ=1.71 for Citrus) is ~ 1 in 1.02 (with lower and upper bounds of ~ 1 in 1.25 to ~ 1 in 1.00, respectively). Based on the crop exposure scenario that results in the smallest RQ values (Eggplant), the likelihood of individual mortality for the highest acute RQs (0.27 for 1.4g, 2.91 for 37g and 0.34 for 238g CRLF) are:
1 in 1.62 x10 6 

### (bounds = 1 in 1 in 9.61 x10 13 

### to 1 in 50.0) for 1.4g CRLF; 1 in 1.00 (bounds= 1 in 1.05 to 1 in 1.00) for 37g CRLF; and 1 in 2.67 x10 4 

### (bounds=1 in 4.65 x10 9 

### to 1 in 21.4) for 238g CRLF.

Ecological Incident Reports

Very few ecological incidents involving endos ulfan have been reported for terrestrial organisms ( Section 4.4 and Appendix L) . Of the seven terrestrial incidents that have been reported for endosulfan, none are cl assified as ‘highly probable’ and two are classified as ‘probable.’ The two ‘probable’ incidents involve birds (b lue jay, crow, owl), mammals (squirrel, opossum, red fox) and an amphibian (unidentified frog). One of the two probable incidents (incident ID: I012626-001) involved morality to a blue jay, a crow, a red fox, and 12 gray squirrels apparently poisoned from an unknown source. A pooled sample of the gastrointestinal tract from four of the gray squirrels was f ound to have 126 ppm endosulfan. The other ‘probable’ ecologica l incident (ID I010533-001) involved apparent human health impacts in addition to anecdotal evidence of food chain transfer and secondary poisoning of endosulfan (termite to frog to owl).

Conclusions Regarding Direct Effects on CRLF

Based on multiple lines of evidence, including:

(1) RQ exceedence of freshwater fish acute and chronic LOCs using model and monitoring-based EEC estimates (2) RQ exceedence of acute listed LOC for for small, medium and large CRLF consuming aquatic prey predicted to bioaccumulate endosulfan (3) RQ exceedence of acute and chronic LOCs for small, medium and large CRLF modeled using T-HERPS,

177

### (4) the high probability of an individual mo rtality occurrence using the highest acute RQ from T-HERPS and for fres hwater fish (~1 in 1), (5) the spatial and temporal overlap am ong endosulfan use and CRLF occurrence and
critical habitat desc ribed previously,

the Agency concludes that agricultural uses of endosulfan in Califor nia have a reasonable
likelihood to cause direct adve rse effects to aquatic and te rrestrial-phase CRLFs should exposure at the predicted EECs actually occur for aquatic and terrestrial-phase CRLF and assuming the sensitivity of CRLF to endosulfan is similar to the most sensitive freshwater fish (for its aquatic phase) and avian species (for it s terrestrial-pha se) selected for RQ calculation.

5.2.1.2 Indirect Effects to CRLF (v ia Potential Loss of Prey)

As discussed previously in Section 2.5 , the diet of aquatic-phase CRLF tadpoles is composed primarily of unicellular aquatic plants (i.e., alg ae and diatoms) and detritus, while the diet of terrestrial-phase CRLF includes terrestrial a nd aquatic invertebrates, mammals, frogs, and fish. The main food source for juvenile aquatic- and terrestrial-phase CRLFs is thought to be aquatic and terrestrial inverteb rates. However, life history da ta for terrestrial-phase CRLFs indicate that large adult frogs al so consume terrestrial vertebrate s, including mice and frogs.

Algae (non-vascular plants)

Based on the most sensitive surrogate aquatic non- vascular plant toxicity data (EC50 value of 428 μg a.i./L for the marine alga, Pseudokirchneriella subcapitatum , and the maximum aquatic peak EEC of all use scenarios used to represent all of the agricultural uses ofendosulfan in CA (5.88 ug/L for Lettuce and Brussels Sprouts), all RQs for aquatic nonvascular plants are ≤ 0.014 (see Section 5.1.1.3 ). Since the RQs do not exceed the Agency’s LOC (1) for aquatic non-vascular plants based on the most sensitive data available to the Agency, labeled endosulfan use in California ap pears not likely to in directly affect the aquatic-phase CRLF via effects to aquatic non-v ascular plant food sour ces. Although the lack of risk to non-vascular aquatic plants is cons istent with the insecticidal mode of action of endosulfan, it should be considered that data were available for only one species of aquatic non-vascular plant that was consid ered suitable for quantitative us e in this risk assessment. In order for potential effects to non-vascular plants to be identified, an untested species must be
at least 75 times more sensitive than the available data for P. subcapitatum. Therefore, only fish, aquatic invertebrates, and frogs will be characterized for potential indirect effects to the aquatic-phase CRLF.

Freshwater Fish and Aquatic-phase Frogs

The potential for direct effects to listed fish and aquatic-phase frogs is discussed above in
Section 5.2.1.1 . Because fish and frogs are also considered potential prey items for the aquatic-phase CRLF, indirect e ffects via potential prey item reduction are also considered here. As previously described, acute RQs based on modeled EECs for freshwater fish (used as a surrogate for the aquatic phase CRLF) range from 7.2 to 58.8, thus exceeding the Agency’s listed LOC (0.05) in all 20 crop scenarios modeled ( Table 5.1 ). Risk quotients based on

178

### maximum reported concentrations of total endosul fan in California surface waters also exceed the Agency’s acute listed LOC. Similarly, chronic RQs range from 5.7 to 80.6 and exceed the Agency’s LOC (1.0) in all 20 crop scenarios mo deled. Available information indicates that the modeled EECs extend well into the cumulative species sensitivity distribution for endosulfan ( Figure 5.3 ). Probit analysis using the default slope of 4.5 for freshwater fish also indicates a high probability of an individual mort ality occurrence (~1 in 1), even with the RQ
associated with the smallest peek EEC (7.2 for Eggplant). The preponderance of reported ecological incidents involves fres hwater fish, which further supports findings of risk to this taxonomic group. Therefore, considering the aforementioned lines of evidence and the potential spatial and temporal overlap of reported endosulfan us e with the occurrence of the CRLF ( Table 5.7 and Appendix E )
, there appears to be a reas onable potential for indirect effects to the aquatic-phase CRLF from loss of fish/aquatic amphibian prey as result of
labeled endosulfan use in Calif ornia provided that exposures o ccur at or near modeled EECs and that the sensitivity of test ed fish is similar to those f ound in aquatic ecosystems from which the CRLF obtains prey.

Freshwater Invertebrates (Water Column Exposure)

Based on surrogate freshwater in vertebrate toxicity data (LC 50 

### value of 0.6 μg a.i./L for mayfly) and modeled aquatic peak EECs for various use scenarios used to represent all of the agricultural uses of endosulfan in CA, acute RQs for freshwater invertebrates range from 1.2 to 9.8 for freshwater invertebrates; exceeding th e Agency’s acute listed species LOC (0.05) in all 20 crop scenarios modeled ( Table 5.2 ). Because the acute RQs all substantially exceed the acute listed LOC of 0.05, the likelihood of morta lity to an individual freshwater invertebrate is considered high (e.g., from ~1 in 1.56 to ~1 in 1; Table 5.11 ).

Based on the distribution of species-mean acute toxicity values for freshwater invertebrates
available from ECOTOX and submitted studies , these minimum and maximum peak acute EECs would exceed the LOC for approximately 45% and 60% of the tested species, respectively (vertical red lines in Figure 5.4 ). As illustrated in Figure 5.4 , the LC50 chosen for quantitative use in this ri sk assessment corresponds to approximately the 15th percentile
when all available data are included in the dist ribution (i.e., those considered appropriate only for qualitative use in addition to those data c onsidered acceptable for quantitative use for RQ calculation). Although those data that fall below the LC50 used for RQ calculation (0.6 ug/L) are not considered acceptable for quantitative us e due to factors such as use of unmeasured exposure concentrations, insufficient documentation of test procedures, in consistency with the results of other acceptable studies (see Appendix J ), they do suggest that effects of endosulfan might occur at concentrations of ab out 1/6th that selected for RQ calculation. The lowest LC50 value in Figure 5.4 is for the 2 nd 

### instar larval stage of the southern house mosquito. We did not consider this value us able because the authors of the study did not provide adequate documentation on how the study was conducted. The exposure concentrations were not listed or measured; the number of organisms used for each treatment was not given; and the few details th at are given are only listed for the 4 th 

### instar. One has to assume that the procedures were th e same for the other life stages.

179

### Freshwater Invertebrates

0.00 0.10 0.20 0.30 0.40 0.50 0.60 0.70 0.80 0.90 1.00

0.001 0.01 0.1 1 10 100 1000 10000 100000

LC50 (μg/L)Fractional Rank

benchmarklowest EEC/LOChighest EEC/LOClowest EEChighest EEC

Figure 5.4 Species sensitivity distribution of the acute toxicity of endosulfan to freshwater invertebrates via water column exposure



### Similarly, chronic RQs calculated from the 21-d EECs exceed the Agency LOC of 1 for all 20 scenarios ( Table 5.2 ). The 21-d EECs range from 0.24 to 2.6 ug/L which correspond to chronic RQs 23.7 and 260, respectively, based on the estimated NOAEC of 0.01 ug/L for the mayfly, Atalophlebia australis . This NOAEC was estimated usi ng an acute-chronic ratio of
61.5 derived from Daphnia magna because the mayfly was a much more acutely sensitive compared to D. magna . However, use of an estimated NOAEC introduces uncertainty into the calculation of the chronic RQ values. Sin ce acceptable data on the chronic toxicity of
endosulfan to freshwater invertebrates are limited to D. magna , chronic toxicity data for
estuarine and marine invertebrates are considered here in order to evaluate the uncertainty associated with the estimated NOAEC of 0.01 ug /L. Specifically, five chronic tests are available for the saltwater mysid, Americamysis bahia , that were conducted using flowthrough and measured exposures (McK enney 1982; ECOTOX reference #3736; Appendix J ). NOAECs from these five tests (0.14 to 0.52 μ g a.i./L) are within an order of magnitude of the estimated NOAEC of 0.01 ug/L for D. magna, thus suggesting the estimated NOAEC is not
unreasonable within the limits of this comparison. Furthermore, if these measured NOAECs were used directly for chronic RQ calculation, the resulting RQs would still exceed the chronic LOC in all 20 exposure scenarios tested. On the other hand, if the measured chronic NOAEC of 2.7 ug/L for D. magna was used for RQ calculati on, none of the calculated RQs would exceed the LOC of 1 (the highest RQ w ould approach 1). However, use of this NOAEC of 2.7 ug/L is not consider ed reasonable for estimating risks from chronic exposure to freshwater invertebrate assemblages because it exceeds the LC50 values for about 30% of

180

### the tested species ( Figure 5.4 ), likely because D. magna is a relatively insensitive invertebrate species.

With respect to measured concentrations of endosulfan in surface water, maximum
concentrations of total endosulfan (0.95 ug/L from 1991-1996; 0.05-0.08 from 2001-2008;
Table 5.14 ) correspond to chronic RQ values of 95 and 5 to 8 for the 1991-1996 and 2001- 2008 sampling periods, respectively, based on a NOAEC of 0.01 ug/L for the mayfly. Acute RQ values based on an LC50 of 0.6 ug/L for ma yfly and these maximum reported endosulfan concentrations are 1.6 for the 1991-1996 sampling period and 0.08-0.13 from the 2001-2008 sampling period and exceed the acute listed LO C of 0.05. Due to the declining pa ttern of endosulfan use in California, data from the 2001-2008 time period are considered more representative of current and likely future us e of endosulfan in California. The acute and chronic RQs based on the maximum reported concentrations from the 2001-2008 time period suggest a potential risk to fr eshwater invertebrates from chronic exposure to endosulfan in
California.

In conclusion, based on: (1) the exceedances of listed species acute and chronic risk LOCs for
freshwater invertebrates for all of the modele d scenarios assessed, (2) the high probability of an individual mortality occurrence using both the highest and lowest acute RQ for freshwater invertebrates, (3) the spatial overlapping of patterns of endosulfan use in California with CRLF habitat ( Table 5.7 ), and (4) the reported aquatic mo nitoring data that exceed acute listed and chronic LOCs, it appears that there are adequate lines of evidence to conclude that there is a potential for indirect effects to th e aquatic-phase CRLF fr om loss of freshwater invertebrate prey as result of labeled endosulfan use in Califo rnia provided that exposures
occur at or near modeled EECs and that the sens itivity of tested freshwater invertebrates is similar to those found in aquatic ecosyst ems from which the CRLF obtains prey.

Freshwater Invertebrat es: Sediment Exposure

As summarized in Section 4.1.2.6 , toxicity data are available fo r freshwater invertebrates via exposure to contaminated sediments for endos ulfan (as endosulfan sulfate). Exposure via
sediments is of interested because it can i nvolve both uptake through re spiration of pore and overlying water in addition to ingestion of contam inated sediment. Chronic risk to freshwater sediment invertebrates is based on is based on 21-day EECs and the lowest chronic toxicity
value for freshwater sediment invertebrates. Ba sed on freshwater sediment toxicity data for endosulfan sulfate in porewater (NOAEC=0.35 μg a.i./L for midge) and 21-day EECs for
various use scenarios used to re present all of the ag ricultural uses of e ndosulfan in CA, all acute RQs for freshwater invertebrates ra nge from 0.26 (eggplant) to 3.37 (lettuce and brussels sprouts). Twelve of the set of 20 m odeled scenarios used to represent all of the agricultural uses of endosulfan in CA resulted in an exceedance of the Agency’s chronic risk LOC (RQ>1) for freshwat er invertebrates (see Table 5.21 ).

Based on exceedances of the Agency’s chronic risk LOC (RQ>1) for 12 of the set of 20 modeled scenarios used to repres ent all of the agricultu ral uses of endosulfan in CA, there is a potential for indirect effects to the CRLF via re duction in its freshwater sediment invertebrate prey base, provided that exposures occur at or near modeled EEC s and that the sensitivity of tested invertebrates via sediment exposure is similar to those found in aquatic ecosystems upon which the CRLF relies for prey.

181Table 5.21 Acute and Chronic RQ s for freshwater sediment invert ebrates based on EECs for use categories used to represen t all endosulfan uses in CA

Use Category Run No. Peak EEC (μg/L) 21-day EEC (μg/L) Chronic RQ (2)

Almonds, Hazelnuts & Walnuts 1 0.37 0.36 1.04

Citrus 1 0.23 0.22 0.63
Broccoli, Cabbage & Cauliflower 1 1.18 1.17 3.34
Collards, Kale & Mustard Green 2 0.38 0.38 1.07
Sweet corn for fresh market only 1 0.51 0.51 1.45
Cotton (ground) 2 0.35 0.34 0.98
Cotton (aerial) 3 0.33 0.32 0.93

All fruit trees 1 0.30 0.30 0.85
Lettuce & Brussels Sprouts 1 1.19 1.18 3.37

Cucurbits 1 0.42 0.42 1.19
Eggplant 3 0.09 0.09 0.26

Ornamentals or Shade Trees (Southern Coast) 1 0.80 0.79 2.27
Ornamentals or Shade Trees (Nort hern Central coast) 1 Add 0.84 0.83 2.36

Potato 1 0.25 0.25 0.70
Potato (Northern Central coast) 1 Add 0.37 0.37 1.05

Sweet Potato 3 0.18 0.18 0.52
Beans & Peas (dry) & Pepper 1 0.39 0.39 1.11
Carrot & Celery 2 0.39 0.38 1.09
Strawberry 1 0.72 0.71 2.03

Tomato 1 0.28 0.27 0.78

(2 ) RQ values in bold indicate exceedence of chronic LOC (1.0 ). Chronic RQs were based on the 21 day average EEC divided by the chronic NOAEC for the midge Chironomus tentans of 0.35 μg/L (MRID 47318101)



### Terrestrial Invertebrates

Terrestrial invertebrates are one of the prey items for terrestrial phase CRLF. As such, impacts to the terrestrial invertebrate prey base of the CRLF have the potential to indirectly
affect the CRLF. As described in Section 5.1.2.3 , the potential risks to terrestrial invertebrates resulting from fo liar spray applications of e ndosulfan were derived using TREX, and the most sensitive toxicity data availa ble for terrestrial invertebrates (acute contact LD50 (0.15 μg a.i./g) for the beet web worm). EECs from the large and small insect categories ranged 37.5 to 337 ppm, respectively, for the crop exposure scenarios yielding the lowest and highest EECs (eggplant a nd citrus fruits, respectively; Table 3.23 ). The resulting RQs for the small insect category ranged fr om 450 to 2250 and RQs calculated for large insects ranged from 50 to 250 ( Table 5.5 ). All 20 use category RQs for both size classes substantially exceeded the Agency’s interi m LOC for listed terres trial invertebrates (RQ>0.05), which is not unexpected given the insectic idal mode of action of this pesticide.

182

### When compared to the acute co ntact toxicity of endosulfan of 35 ug/g based on the honey bee (calculated from an LD50 of 4.5 ug/bee us ing a body weight of 0.128g; MRID 000199), the adult beet web worm (a target insect) is approximately 230 times more sensitive (LD50 of 0.15 ug/g). If RQs were calculated based on th e standard honey bee acute contact LD50 (35 ug/g), the smallest RQ (1.1 for eggplant) would still exceed the Agency ’s interim acute listed LOC for terrestrial invertebrates by nearly 20-f old. When compared to the distribution of acute contact toxicity of endosulfa n to terrestrial invertebrates ( Figure 5.5 ), the lowest EEC for small insects (337 ppm) and large insects (37.5 ppm) approximate the 99 th 

### and 80 th 

### percentiles, respectively.

Terrestrial Insects

0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0

0.1 1 10 100 1000

LD50 ( μ g/g)Fractional Rank Honey Bee

beetle larva

beetle adult

moth larva

moth adult



### Figure 5.5 Species sensitivity distribution of the acute contact toxicity of endosulfan TGAI to
terrestrial invertebrates ba sed on species mean values.

Given the large acute RQs, the probit-based li kelihood estimates of i ndividual mortality all indicate a high probability for mortality to individual terrestrial insects (~1 in 1; Table 5.12 ). No reported ecological incidents associated w ith endosulfan involved terrestrial insects; however it is likely that impacts to terrestrial insects would be substa ntially under-reported in the EIIS database due to the difficulty in observing and documenting causal linkages between endosulfan use and non-target terrestrial insects.

Based on the exceedences of the Agency’s inter im LOC for listed terrestrial invertebrates, endosulfan use in CA does have the potential to indirectly affect the CRLF through reduction in terrestrial prey base, provide d that exposures occur at or near modeled EECs and that the sensitivity of tested terrestria l invertebrates via acute contact exposure is similar to those found in terrestrial ecosystems upon which th e CRLF utilizes as a prey source.

183

### Small Terrestrial Vertebrates

For endosulfan spray applications, dietary-based and dose-based exposures of terrestrialphase CRLF to potential small terrestrial vert ebrate prey (mammals and amphibians) are assessed using small mammals (15 g) which cons ume short grass, and small birds (20g; they represent terrestrial-phase amphibians that it may consume) which consume small (broadleaf plants/small insects dietary category) and la rge (fruits/pods/seeds/large insects dietary category) invertebrates using the T-REX model described earlier in Section 5.2.1.1.

RQ values representing direct exposures of e ndosulfan to terrestrial-phase CRLFs are also used to represent exposures of endosulfan to am phibians in terrestrial habitats that may serve as prey for the CRLF. For terrestr ial-phase amphibians, as described in Section 5.2.1.1 , the Agency concluded that agricultural uses of endosulfan in California have a reasonable
likelihood to cause direct advers e effects to terrestrial-phase CRLFs should exposure at the predicted EECs actually occur for a terrestrial-phase CRLF and assuming its sensitivity to
endosulfan is similar to the most sensitive av ian species selected for RQ calculation. Furthermore, dose-based RQs determined from T-HERPS modeling for the 1.4g and 37g amphibians are used to bracket the potential ri sks to a specific prey item (Pacific tree frog, 2.3g) of the terrestrial-phase CRLF. Please refer to Section 5.2.1.1 for additional discussion and characterization of potential risks to terrest rial-phase amphibians that may serve as prey for the terrestrial-phase CRLF. Therefore, that Agency concludes that endosulfan use in CA does have the potential to indi rectly adversely affect the CRL F through reduction in terrestrial vertebrate prey base (birds and other amphibian s), provided that exposures occur at or near
modeled EECs and that the sensitiv ity of tested avian and amphibi an prey is similar to those found in terrestrial ecosystems upon which th e CRLF utilizes as a prey source. Regarding the potential effects on the small mamm al prey base of the CRLF, the Agency used surrogate toxicity data (LD 50 

### =10 mg/kg-bw and NOAEL = 15 mg/kg-diet), the maximum allowable application rate (1 application, 2.5 lbs a.i./acre/app lication), the foliar dissipation half-life of 4 days for endosulfan from W illis and McDowell (1987), and upper bound Kenaga values from T-REX, there is a potential for di rect adverse effects on SMHM individuals from foliar spray applications of endosulfan in CA ( Table 5.4 ) . Although EECs for small mammals feeding on short grass yield the highest risk estimates, it appear s that the impacts of endosulfan use to the SMHM potentially extend beyond those feeding on short grass.

For spray applications of endosulfan, the dose-based acute RQs range from 5.21 to 26.03, from 2.39 to 11.93, from 2.93 to 14.64, and from 0.33 to 1.63 for the short grass, tall grass, broadleaf plants/small insects, and fruits/pod s/seeds/large insects dietary categories, respectively. For acute dose-based RQs, a ll modeled scenarios (N =20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ> 0.1) for mammals that feed on short grass, tall grass, broadleaf plants/small insects, and fruits/pods /seeds/large insects.

The dose-based chronic RQs ranged from 69.41 to 347.04, from 31.81 to 159.06, from 39.04 to 195.21, and from 4.34 to 21.69, for the short grass, tall grass, broadleaf plants/small insects, and fruits/pods/seeds/large insect dietary categories, respectively. For chronic dose-based RQs, all modeled scenarios (N= 20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short gra ss, tall grass, broadleaf plants/small insects, and fruits/pods /seeds/large insects.

184

### Estimates of the likelihood of mortality to individual 15g mammalian prey resulting from predicted endosulfan EECs range from ~1 in 70 for large insects base d on the eggplant crop exposure scenario to ~1 in 1 for th e citrus fruits exposure scenario.

The dietary-based chronic RQs range from 8 to 40.00, from 3.67 to 18.33, from 4.50 to 22.50, and from 0.50 to 2.50, for the short grass, tall grass, broadleaf plan ts/small insects, and fruits/pods/seeds/large insects di etary categories, respectively. For chronic dietary-based RQs, all modeled scenarios (N=20) resulted in an exceedance of the Agency ’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short grass, tall grass, and broadleaf plants/small
insects. Thirteen out of 20 modeled scenar ios resulted in an exceedance of the Agency’s chronic risk LOC (RQ ≥ 1) for mammals that feed on fruits/pods/seeds/large insects. Therefore, RQs exceed the Agency’s acute listed species LOC (RQ> 0.1) and chronic risk LOC (RQ> 1) for mammals (see Table 5.4 ) for foliar spray applic ations of endosulfan.

Therefore, that Agency concludes that endos ulfan use in CA does have the potential to indirectly affect the CRLF through reduction in terrestrial vertebrate prey base (small mammals), provided that exposures occur at or near modeled EEC s and that the sensitivity of tested mammalian prey is similar to thos e found in terrestrial ecosystems upon which the CRLF utilizes as a prey source.

5.2.1.3 Indirect Effects (via Habitat Effects)

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 struct ure, rather than energy, to the system, as attachment sites for many aquatic invertebrates, and refugia for juvenile organisms, such as fish and frogs. Emergent plants help redu ce sediment loading and provide stability to
nearshore areas and lower streambanks. In addi tion, vascular aquatic pl ants are important as attachment sites for egg masses of aquatic speci es. No toxicity data were available for vascular aquatic plants that were considered a ppropriate for quantitative or qualitative use in this assessment. For non-vascular aquatic plants, the maximum RQ calculated is s ≤ 0.014 (see Section 5.1.1.3 ). Since the RQs do not exceed the Agency’s LOC (1) for aquatic nonvascular plants based on the most sensitive data available to the Agency, labeled endosulfan use in California will not indirectly affect the aquatic-phase CRLF via effects to aquatic habitat based on non-vascular aquatic plants.

Terrestrial plants serve several important hab itat-related functions for the listed assessed species. In addition to providing habitat and cover for invertebra te and vertebrate prey items of the listed assessed species, terrestrial vege tation also provides sh elter and cover from predators while foraging. Upland vegetation including grassland and woodlands provides cover during dispersal. Riparian vegetation helps to maintain the integrity of aquatic systems by providing bank and thermal stability, serving as a buffer to filter out sediment, nutrients, and contaminants before they reach the watershe d, and serving as an energy source. No data on the effects of endosulfan on terrestrial plan ts were considered ac ceptable for quantitative use in this risk assessment. Based on efficacy studies, however, available information

185

### indicates that agricultural cr ops are not adversely affected by endosulfan use rates that are associated with pest control. This, in conjunc tion with the insecticid al mode of action of endosulfan, suggests that terrestri al plants may not be sensitive to endosulfan compared to aquatic and terrestrial animals. However, use of efficacy studies can be confounded by lack of experimental controls, multiple stressors (pes ticide and insect pest), and plant species that may not be representative of those upon which the CRLF may depend.

5.2.1.4 Effects to Designated Critical Habitat

Aquatic-Phase PCEs

Three of the four assessment endpoints for th e 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 ge ometry and/or increase in sediment deposition within the stream channel or pond: aquatic ha bitat (including riparian vegetation) provides for shelte r, foraging, predator avoidance, and aquatic dispersal for juvenile and adult CRLFs.

• Alteration in water chemistry/quality in cluding temperature, turbidity, and oxygen content necessary for normal growth and vi ability of juvenile and adult CRLFs and
their food source.

• Reduction and/or modification of aquatic-b ased food sources for pre-metamorphs ( e.g., algae).

Conclusions for potential indire ct effects to the CRLF via di rect effects to aquatic and terrestrial plants are used to determine whethe r effects to critical ha bitat may occur. As discussed above for aquatic plan ts and terrestrial plants ( Section 5.2.1.3 ), labeled endosulfan use in California will not indirectly affect the CRLF via impacts to habitat and/or primary production.

The remaining aquatic-phase PCE is “alteration of other chemical characteristics necessary for normal growth and viability of CRLFs and th eir food source.” Other than impacts to algae as food items for tadpoles (discussed above), this PCE is assessed by c onsidering direct and indirect effects to the aquatic-phase CRLF via acute and chronic freshwater fish and invertebrate toxicity endpoints as measures of effects. Based on the analyses discussed above, there is a potential for habitat effects via impacts to aquatic-phase CRLFs ( Sections 5.2.1.1 )
and effects to freshwater invert ebrates and fish as food items ( Sections 5.2.1.2 ) from
endosulfan use in California.

Terrestrial-Phase PCEs

Two of the four assessment endpoints for the te rrestrial-phase PCEs of designated critical habitat for the CRLF are related to poten tial effects to terrestrial plants:

• Elimination and/or disturbance of upland ha bitat; ability of hab itat to support food source of CRLFs: Upland areas within 200 ft of the edge of the ri parian vegetation or

186

### drip line surrounding aquatic a nd riparian habitat that ar e comprised of grasslands, woodlands, and/or wetland/ri parian plant species that provides the CRLF shelter, forage, and predator avoidance.

• Elimination and/or disturbance of dispersa l 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 site s including both natural and altered sites which do not contain barriers to dispersal.

As discussed above for terrestrial plants ( Section 5.2.1.3 ), labeled endosulfan use in California will not indirectly affect the CRLF via impacts to habitat and/or primary production.

The third terrestrial-phase PCE is “reducti on and/or modification of food sources for terrestrial phase juvenile s and adults.” To assess the impact of endosulfan on this PCE, acute and chronic toxicity endpoints for terrestrial invertebrates, mammals, and terrestrial-phase frogs are used as measures of effects. Based on the potential for a reduction in mammalian, terrestrial invertebrate, and amphibious prey items from registered endosulfan use ( Section
5.2.1.2 ), the Agency concludes there is a potential for habitat effects via indirect effects to terrestrial-phase CRLFs via reduction in prey base.

The fourth terrestrial-phase PCE is based on al teration of chemical characteristics necessary for normal growth and viability of juvenile and adult CRLFs and their food source. Based on the preceding discussions, the Agency conclude s there is a potential for habitat effects via direct ( Section 5.2.1.1 ) and indirect effects ( Section 5.2.1.2 ) to terrestrial-phase CRLFs.

5.2.2 California tiger salamander

5.2.2.1 Direct Effects

Endosulfan is currently register ed for numerous diverse agricu ltural uses that span a large variety of geographical regions throughout the en tire state of California. Therefore, there is the potential for endosulfan use acro ss the state to spatially and temporally coincide with the CTS breeding season.

The CTS has aquatic phase eggs and larvae and terrestrial phase juveniles and adults. Aquatic-phase CTS inhabits low elevation vern al pools and seasonal ponds while juvenile and adults are found in associated grassland, oak savannah, and coastal scrub plant communities. Although aquatic phase CTS are adapted to na tural vernal pools and ponds, they are frequently found in manmade or modified e phemeral and permanent ponds, including stock ponds. Terrestrial phase CTS pref er open grassland to areas of continuous woody vegetation and may live for up to 10 years, spending the majo rity of their lives in the upland habitats. The upland component typically consists of gr assland savannah, but also can consist of grasslands with scattere d oak trees, and scrub and chaparra l habitats. Juvenile and adult CTS spend the dry summer and fall months in th e burrows of Califor nia ground squirrels ( Spermophilus beecheyi ) and Botta’s pocket gopher ( Thomomys bottae ). California tiger

187

### salamanders cannot dig their own burrows, and as a result their presence is associated with
active burrows of small mammals such as ground squirrels and pocket gophers.

The young aquatic larvae eat small crustaceans, al gae, and mosquito larvae. When they are large enough, they begin to take advantage of aquatic insects, invertebrates and tadpoles of Pacific treefrogs, California red-legged frogs, we stern toads, and spadefoot toads. Once they reach metamorphosis, which is usually by late sp ring or early summer, juveniles are ready to roam to their terrestrial nesting habitat and may disperse up to two miles from their natal ponds. As adults, CTS feed on terrestrial in vertebrates, insects, frogs, and worms.

From southern Colusa County south to northern Kern County, CTS habitat is disjunct remnant vernal pool complexes and isolated ponds scat tered mainly along narrow strips of rangeland on each side of the Central Valley. From Suisun Bay south to the Temblor Range, CTS are found in sag ponds and human-maintained stock ponds in the coastal ranges. Populations of
CTS are also located in Sonoma and Santa Barbara counties.

Temporal and Spatial Overlap

A comparison of Figure 5.1 and Figure 5.6 indicates that endosulfan use and CTS sensitive life stages (larvae, young juveni les) could potentially overlap in time. A peak in endosulfan application in Feb-March coincides with larval development. Application from May - October coincides with young juvenile dispersal.

Young Juveniles

Larvae
Breeding/Egg
Masses

J F M A M J J A S O N D

Figure 5.6 CTS Reproductive Even ts by Month; Adults and juve niles can be present all year



### Since pesticide use information is only availabl e at the county level, the degree that the CTS
or its critical habitat ac tually coincides in the same or similar locations cannot be precisely determined. With this limitation in mind, the spatial overlap of average endosulfan use for 2005-06 reported by CDPR/PUR and CTS distri bution (including critical habitat) is summarized at the county level in Table 5.7

. Figure 5.7 summarizes the overlap in average endosulfan use and species/habitat occurrence for all 7 species asse ssed. For the CTS, Approximately 85% of endosulfan use (74,196 lbs) is applied in counties in which the CTS or
its critical habitat occurs.

While Figure 5.7 suggests a significan t potential overlap in endosulfan use and the
occurrence of CTS or its critic al habitat at the county level , review of the overlap between cultivated and orchard crop use a nd the occurrence of the CTS (or its critical ha bitat) suggests a much smaller amount of spatial overlap currently occurs ( Figure E.7 of Appendix E ). Specifically, most of the CTS habitat is on the fri nge of the cultivated crop/orchard land use area of the San Joaquin valley. However, due to the documented long-range transport of

188

### endosulfan to the Sierra Nevada mountains of Ca lifornia (e.g., Fellers et al., 2004), the critical
habitat east of the cult ivated crop/orchard use area may be subject to endosulfan exposure.

53,053

0.25 1,120 0.00 4.56 71,104 74,196

0 10,000 20,000 30,000 40,000 50,000 60,000 70,000 80,000

CRLF SFGS SMHM BCB VELB SJKF CTS

SpeciesAverage Use (lbs)

Figure 5.7 Average Endosulfan Use (2005-2006) in Co unties with Reported Occu rrence of Listed Species, Occupied Core Areas and/or Critical Habitat



### Direct Exposure of Aquatic and Terrestrial Phase CTS

The RQ values representing exposures of endos ulfan to freshwater fish and aquatic-phase amphibians that described the dir ect effects to aquatic-phase CRL F are also used to represent exposures of endosulfan to the aquatic-phase CTS. As described in Section 5.2.1.1 , the Agency determined a reasonable potential for di rect effects on freshw ater fish and aquaticphase amphibians based on LOC exceedences from model- and monitoring-based RQs, the high probability of individual mortality, and eco logical incident reports. Similarly, the Agency determined a reasonable potential exists for direct effects on birds (surrogate for terrestrial phase amphibians) based on exposur e to food items receiving direct deposition from endosulfan application (i.e., T-REX, T-HERPS modeling) and consumption of contaminated aquatic prey (i.e., KABAM bi oaccumulation modeling for small CRLF which was used as a surrogate for esti mating CTS exposure potential).

Consumption of Contaminated Terrestrial Prey

The CTS is also known to consume worms as part of its diet. The T-REX model is useful for assessing exposures of terrestrial animals to pe sticides through consumption of foliar surfaces of crops and insects on the treated site. Th e model cannot be used to assess pesticide exposures to terrestrial animals resulting fr om consumption of soil dwelling invertebrates which have accumulated the pesticide in their tissues. In order to explore the potential exposures of terrestrial-phase CTS to total residues of endosulfan that have accumulated in earthworms inhabiting endosulfan-treatment sites, a simple fugacity approach was employed
to estimate endosulfan concentrations in ear thworms based on predicted concentrations in soil. As with the T-REX modeling, birds were us ed as a surrogate for te rrestrial-phase CTS. Therefore, application rates, the foliar dissipatio n rate, toxicity da ta, body weights and

189

### consumption weights were identical to that us ed for the avian T-REX modeling described in
Section 5.1. A log Kow for endosulfan of 4.76 was used based on the weighted mean Kow for alpha and beta isomers of 70:30, resp ectively (MRID 414215-01). A soil distribution coefficient (Kd) of 69 cm 3 

### /g was used based on the weighted mean Kd for alpha and beta isomers of 70:30, respectively (MRID 414129-06). This Kd represents the lower range of
four Kd values available for different soils in this study, wherein an upper range of Kd were
320 and 428 cm 3 

### /g for alpha and beta endosulfan was re ported. Using the lower value for Kd represents a conservative assumption since for a given Kow, concentrations in earthworms increase with decreasing Kd. For this anal ysis, the two crop exposur e scenarios that produce the highest and lowest dietary EECs (Citrus/Fruit s and Eggplant, respectively) resulting from soil exposure via fugacity modeling were evalua ted in order to provide information on the overall range of potential risks to terrestrial-phase CTS consum ing contaminated earthworms. Risks were evaluated for the 20g and 100g avian size classes, which bracket the estimated mass of adult CTS (50g). Details on this approach are provided in Appendix N

.

PRZM estimated endosulfan concentrations in soil and soil pore wa ter of 22.4 and 0.183 g/m 3



### , respectively, for the Citrus and 5.3 and 0.066 g/m 3 

### , respectively, for the Eggplant crop exposure scenarios. Based on these concentrati ons, the estimated concentration of endosulfan in earthworms is 223 and 64 ppm for C itrus and Eggplant, respectively ( Table 5.22 ). These
values translate into dose-based EECs that range from 41.7 to 254 mg/kg-bw, depending on body weight and the crop exposure scenario. Acute dose-based RQs (2.3-17.5) exceed the avian, acute listed species LOC of 0.1 for both crop exposure s cenarios, regardless of body weight. Acute dietary-based RQ s (0.08-0.28) exceed the avian, acu te listed LOC fo r the Citrus crop scenario but approach the LOC for the Eggpl ant scenario. Finally, chronic dietary-based RQs (2.1-7.4) exceed the LOC of 1 for both crop s cenarios. Sensitivity analysis indicates that LOCs would be exceeded even if the higher Kd va lues were selected. Therefore, based on the assumptions that: (1) the sensitivity and e xposures to small and medium size birds are reasonable surrogates for the CTS and (2) the CTS receives 100% of its diet from earthworms, there is a potential for direct effects on terrestrial-phase CTS from the consumption of contaminated earthworms from fi elds treated with endosulfan. It is noted that
even if the dose of endosulfan to the CTS wa s reduced to 50% of current estimate, (i.e., through lower earthworm consumption rates or lower concentrations), exceedence of acute
and chronic LOC w ould still occur.

Table 5.22 Estimated concentrations of total endosulfan in earthworms and avian risk quotients for two crop exposure scenarios.

Eggplant Citrus

Results* 20g 100g 20g 100g
Dose-based EEC (1) (mg/kg-bw) 73.1 41.7 254 145
Acute Dose-based RQ (2,3) 5.0 2.3 17.5 7.8
Diet-based EEC (1) (ppm w.w. in earthworm) 64 223 Acute Dietary-based RQ (2,4) 0.08 0.28 Chronic Dietary-based RQ (2,5) 2.1 7.4



### 190* Birds are used as a surrogate for terrestrial-phase amphibians (1) Based on fugacity modeling for earthworm using total endosulfan concentrations in soil and soil pore water of 22.4 and 0.183 g/m 3 , respectively for Citrus and 5.3 and 0.066 g/m 3 , respectively, for Eggplant exposure scenarios; See Appendix N for details. (2) RQ values in bold exceed the acute listed sp ecies LOC of 0.1 or the chronic LOC of 1.0 (3) Acute dose-based RQs calculated using the dose-based EECs and adjusted, acute dose-based toxicity values of 14.5 and 18.5 mg/kg-bw for the 20g and 100g bird, respectively. Unadjusted LD50 = 28 mg/kg-bw based on mallard duck (MRID 136998). (4) Acute diet-based RQs calculated using diet-based EECs and a diet-based LC50 of 805 ppm for bobwhite quail (MRID 22923) (5) Chronic diet-based RQs calculated using diet-based EECs and an avian dietary NOAEC of 30 ppm for mallard duck (MRID: 40335001)



### Spatial Overlap

For the CTS, a relatively small amount of overl ap was identified based on GIS mapping of the
occurrence of CTS or its cr itical habitat and cultivated crop/orchard use areas (Figure E.7 of Appendix E) , suggesting a potential for spatial overlap in endo sulfan use and subsequent exposure. Therefore, assuming that the sensitivit y of tested freshwater fish species reasonably approximates the distribution of sensitivities of aquatic-phase CTS, there appears to be a reasonable potential for direct effects to the a quatic phase CTS as result of labeled endosulfan use in California, particularly for those areas where crop/orchard sites, endosulfan use, and CTS occurrence overlap.

5.2.2.2 Indirect Effects ( via Reductions in Prey Base )

Potential forage items of aquatic phase CT S includes algae, snails, zooplankton, small crustaceans, aquatic larvae, aqua tic invertebrates, and smaller tadpoles of Pacific tree frogs, CRLF, and toads. Forage items for the terrestrial phase include terrestrial invertebrates, insects, frogs, and worms

Freshwater Fish and Aquatic-phase Amphibians

RQ values representing exposures of freshw ater fish and aquatic-phase amphibians to endosulfan that may serve as prey for the aquatic-phase CRLF are also used to represent exposures to freshwater fish and aquatic-phase amphibians that may serve as prey for the
CTS. As described in Section 5.2.1.2 , the Agency determined a reasonable potential for direct effects on freshwater fish and aquati c-phase amphibians based on RQ exceedences of listed LOCs for freshwater fish and aquatic phase amphibians using modeled and monitoring data-based EECs, the high probability of an i ndividual mortality occurrence for all crop use scenarios, the high percentage of freshwater fi sh that would be affected at model-based EECs and the reported number of probable and hi ghly probable aquatic incidents involving
endosulfan and fish.

For the CTS, a relatively small amount of overl ap was identified based on GIS mapping of the
occurrence of CTS or its cr itical habitat and cultivated crop/orchard use areas (Figure E.7 of Appendix E) , suggesting a potential for spatial overlap in endo sulfan use and subsequent

191

### exposure. Therefore, assuming that the sensitivit y of tested freshwater fish species reasonably approximates the distribution of sensitivities of freshwater fish and aquatic-phase amphibians used as prey by the CTS, there appears to be a reasonable potential for i ndirect effects to the aquatic phase CTS as result of labeled endosulfa n use in California, particularly for those areas where crop/orchard sites, endosul fan use, and CTS occurrence overlap.

Freshwater Invertebrates

RQ values representing exposures of endosulfan to freshwater invertebrates that may serve as prey for the aquatic-phase CRLF are also used to represent exposur es of endosulfan to freshwater invertebrates that may serve as prey for the CTS. As described in Section 5.2.1.2

, the Agency determined that based on the exce edances of non-listed species acute and chronic
risk LOCs for freshwater invertebrates for a ll of the modeled scenarios assessed and the high probability of an individual mortality occurren ce using both the highest and lowest acute RQ for freshwater invertebrates, there appears to be a potential for direct effects to freshwater
invertebrates as result of labeled endosulfan use in California.

For the CTS, a relatively small amount of overl ap was identified based on GIS mapping of the
occurrence of CTS or its cr itical habitat and cultivated crop/orchard use areas (Figure E.7 of Appendix E) , suggesting a potential for spatial overlap in endo sulfan use and subsequent exposure. Therefore, assuming that the sensitiv ity of tested freshwater invertebrate species reasonably approximates the distribution of sensit ivities of freshwater invertebrates and used as prey by the CTS, there appears to be a re asonable potential for indi rect effects to the aquatic phase CTS as result of labeled endosulfa n use in California, particularly for those areas where crop/orchard sites, endosul fan use, and CTS occurrence overlap.

Terrestrial Invertebrates

RQ values representing exposures of endosulfan to terrestrial invertebrates that may serve as prey for the terrestrial-phase CRLF are also us ed to represent exposures of endosulfan to terrestrial invertebrates that may serve as prey for the CTS. As described in Section 5.2.1.2

, the Agency determined that based on the fact that endosulfan is a highly efficacious broad spectrum insecticide, exceedances of the Ag ency’s interim LOC for listed terrestrial
invertebrates for all of the modeled scenarios as sessed, the high percentage of tested terrestrial invertebrate species that woul d be affected at the modeled EECs and the high probability of an individual mortality occurrence based on the RQs for terrestrial invertebrates, there appears to be a reasonable potential for direct eff ects to terrestrial invertebrates as a result of
labeled endosulfan use in California.

For the CTS, a relatively small amount of overl ap was identified based on GIS mapping of the
occurrence of CTS or its cr itical habitat and cultivated crop/orchard use areas (Figure E.7 of Appendix E) , suggesting a potential for spatial overlap in endo sulfan use and subsequent exposure. Therefore, assuming that the sensitivit y of tested terrestrial invertebrate species reasonably approximates the distribution of sensitiv ities of terrestrial invertebrates and used as prey by the CTS, there appears to be a reasonable potential for indi rect effects to the terrestrial

192

### phase CTS as result of labeled endosulfan use in California, particularly for those areas where crop/orchard sites, endosulfan us e, and CTS occurrence overlap.

Aquatic and Terrestrial Plants

As noted in Section 5.2.1.3, no data are available to relia bly, quantitatively evaluate the effects and the potential risks of endosulfan to vascular aquatic plants. No incidents have been reported to the Agency that involve any aquatic plants, despite that it is regularly directly applied on or near a very wide variety of ag ricultural plants. Only one reported incident involved plants and this was clas sified as ‘possible,’ but the plant species wa s not identified ( Section 4.4 and Appendix L ). No data on the effects of endosulfan on terrestrial plants were considered acceptable for quantitative use in this risk assessment. Based on efficacy studies, available information i ndicates that agricultural crops are not adversely affected by endosulfan use rates that are associated with pe st control. This, in conjunction with the
insecticidal mode of ac tion of endosulfan, suggests that terres trial plants may not be sensitive to endosulfan compared to aquatic and terrestria l animals. However, use of efficacy studies can be confounded by lack of experimental controls, multiple stressors (pesticide and insect pest), and plant species that may not be representative of those upon which the CTS may depend. Therefore, although effects to aquatic a nd terrestrial plants cannot be quantified due to the lack of data, the available lines of ev idence provide no compelling reason to believe that there is a potential for indi rect effects to the CTS from loss of plant food items as result of
labeled endosulfan use in California.

5.2.2.3 Modification to Design ated Critical Habitat

The primary constituent elements (PCEs) of the CTS critical habitat include:

• 

### (PCE1) Standing bodies of fresh water, including natural and man-made (e.g., stock) ponds, vernal pools, and dune ponds , and other ephemeral or permanent water bodies that typically become inunda ted during winter rains and hold water for a sufficient length of time (i.e., 12 week s) necessary for the species to complete the aquatic (egg and larval) portion of its life cycle.

• 

### (PCE2) Barrier-free uplands adjacent to breeding ponds that contain small
mammal burrows. Small mammals are e ssential in creati ng the underground habitat that juvenile and adult Califo rnia tiger salamanders depend upon for food, shelter, and protection from the elements and predation.

• 

### (PCE3) Upland areas between breeding loca tions (PCE 1) and areas with small mammal burrows (PCE 2) that allow for dispersal among such sites.

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants

Aquatic plants serve several important functi ons in aquatic ecosystems such as primary production (non-vascular, vascular) and refugia structure (vascular plants). Rooted plants help reduce sediment loading and provide stability to nearshore areas and lower streambanks. In addition, vascular aquatic plants are important as attachme nt sites for egg masses of aquatic species. Terrestrial plants serve several impor tant functions such as providing habitat and

193

### cover for invertebrate and vertebrate prey items of the CTS. Te rrestrial 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, nutrients, and cont aminants before they reach the watershed, and serving as an energy source.

As stated in Section 5.2.1.3 covering the evaluation of potenti al indirect effects to the CRLF via habitat effects, a lthough effects to vascular aquatic and terrestrial plants cannot be quantified due to the lack of data, available lines of evidence provide no compelling reason to believe that endosulfan will affect any type of plants to the extent that it would affect the habitat integrity of the CTS. Labeled endosulfa n use in California appears not to indirectly
affect the CTS via impacts to habitat and/or primary production. Please refer to Section
5.2.1.3 for additional discussion and characterization of potential risks to plants that may be foraged upon by the CTS.

5.2.3 San Francisco Garter Snake

5.2.3.1 Direct Effects

Endosulfan is currently register ed for numerous diverse agricu ltural uses that span a large variety of geographical regions throughout the en tire state of California. Therefore, there is the potential for endosulfan use acro ss the state to spatially and temporally coincide with the SFGS breeding season.

Temporal and Spatial Overlap

SFGSs mate in the spring (March and April) and fall (September through November), with mating being heavily concentrated in the firs t few warm days of March. Female SFGS can store the male’s sperm over the winter and can retain viable sperm for periods ranging from 3 to 53 months. Ovulation in the common garter snake typically occurs in late spring with pregnancy occurring in early summer. The young are typically born about three to four months after successful mating. SFGS are ovoviviparous, and fema les give birth from June through September with young typically born in July or August; however, young can be born as late as early September. Typically, neonate snakes, 18 to 20 cm in length, are born in the upland areas near the aquatic f eeding habitats and disperse immediately after they are born.

194

### Figure 5.1 and Figure 5.8 show the extent that endosulfan us e and SFGS sensitive life stages (young juveniles) could potential ly overlap. Endosulfan application from May - October coincides with young juvenile birth.

Young Juveniles (Neonates)

Breeding/Egg
Masses Breeding/Egg Masses



### J F M A M J J A S O N D

Figure 5.8 SFGS Reproductive Events by Month; Adults can be present all year



### All known populations of the San Francisco gart er snake occur in San Mateo County near freshwater marshes, ponds, and slow-moving st reams along the coast. Since pesticide use information is only available at the county le vel, the degree that the SFGS and endosulfan actually coincide cannot be precisely determin ed. The spatial overlap of endosulfan use and
SFGS distribution is summarized at the county level in Table 5.7 and Figure 5.7 . Only 0.25 lb ai were reported used from 2005-2006 that coincided with San Ma teo County, less than 0.001% of the total endosulfan use. Thus, the prospect of spatial ove rlap between current endosulfan use and SFGS occurrence appears negligible. The long-range transport of endosulfan would extend exposure beyond curren t crop/orchard/vineyard areas in other counties, however, the prevailing winds would li kely lead to dispersal eastward, away from SFGS occurrence regions in San Mateo County. If cultivated crop/orchard/vineyard uses are considered areas of potentia l endosulfan use in the future, then a substantial amount of spatial overlap can be observed relative to the total area of SFGS o ccurrence sections ( Figure E.2 of Appendix E ).

Direct Exposure

Direct acute and chronic exposur es of the SFGS were evaluated using the same approaches employed for estimating direct exposur es to the terrestrial-phase CRLF ( Section 5.2.1.1 ). In addition, toxicity estimates for both listed spec ies, the terrestrial-pha se CRLF and the SFGS, are based on the same surrogate avian toxicity data. Therefore, RQ values representing the potential for direct exposures a nd effects of endosulfan to the terrestrial-phase CRLF, are also used to represent the potential for direct exposures and effect s of endosulfan to the SFGS.

Based on the risk characterization presented in Section 5.2.1.1 for terrestrial-phase CRLF, there is potential for labeled endosulfan use to cause direct adverse effects to the SFGS via chronic toxicity based on the weight-of-ev idence involving acute a nd chronic risk LOC
exceedances with T-REX and the refined T-HER PS model. However, the average amount of

current endosulfan use at the county level and SF GS distribution do not coincide, and direct effects to the SFGS appear to be unlikely based on current endosulfan use patterns ( Figure
5.7 ). Although the potential for endosulfan to be transpor ted long distances from the application site could extend exposure well beyond current use area s, such long-range transport would need to overcome the direction of the prevailing winds (west to east) in order
to reach SFGS occurrence sections in San Ma teo County, which appears unlikely. Refer to
Section 3.2.4.4 for more information on long-range transport of endosulfan. If cultivated crop/orchard/vineyard uses ar e considered areas of potentia l endosulfan use in the future, then

195

### a substantial amount of spatial overlap can be observed relative to th e total area of SFGS occurrence sections ( Figure E.2 of Appendix E ). Therefore, based on the potential future use of endosulfan in cultivated crop/orchard/vineyard areas of San Mateo County, there appears to be a reasonable potential for direct effects on SFGS from labeled uses of endosulfan.

5.2.3.2 Indirect Effects ( via Reductions in Prey Base )

Newborn and juvenile SFGS prey almost excl usively on Pacific tree frogs in temporary pools during the spring and early summer to the point that the SFGS may be so dependent on their anuran prey that they are not able to switch to other available prey sources if necessary to survive. SFGS under 500 mm snout-to-vent length (SVL) require Pacific tree frogs in various stages of metamorphosis, whereas individuals over 500 mm SVL can consume Pacific tree frog, CRLF, and bullfrog tadpoles and adults.

The main diet of adult SFGS consists of CRLF. Adult SFGSs may also feed on smaller juvenile non-native bullfrogs ( Rana catesbeiana ). Immature California newts ( Taricha

torosa ), California toads ( Bufo boreas halophilus ), recently metamorphosed western toads ( Bufo boreas ), threespine stickleback ( Gasterosteus aculeatus ), and non-native mosquito fish ( Gambusia affinis ) are also known to be consumed by SFGS. Small mammals, reptiles, amphibians, possibly invertebrates, and some fish species may also be consumed by the
SFGS.

Freshwater Fish and Aquatic-phase Amphibians RQ values representing exposures of endosul fan to freshwater fish and aquatic-phase amphibians that may serve as prey for the aquatic-phase CRLF are also used to represent exposures of endosulfan to freshwater fish a nd aquatic-phase amphibians that may serve as prey for the SFGS. As described in Section 5.2.1.2 , the Agency determined a reasonable potential for direct effects to freshwater fish and aquatic-phase amphibians based on RQ exceedences of listed LOCs for freshwater fish and aquatic phase amphibians using modeled and monitoring data-based EECs, the high probability of an individual mortality occurrence for all crop use scenarios, the high percentage of freshwater fish that would be affected at model-based EECs, and the reported number of probable and highly probable aquatic incidents involving endosulfan and fish

As discussed in Section 5.2.3.1 for direct effects on the SFGS, there does appear to be a potential for spatial overlap between SFGS distribution and cultivated/orchard/vineyard agricultural areas where endosulfa n could be used in the futu re, although overlap in current use patterns appears negligible. Therefore, ba sed on the potential future use of endosulfan in cultivated crop/orchard/vineyard areas of San Mateo County, ther e appears to be a reasonable potential for indirect effects on the SFGS from loss of freshwater fish and amphibian prey
items.

Freshwater Invertebrates RQ values representing exposures of endosulfan to freshwater invertebrates that may serve as prey for the aquatic-phase CRLF are also used to represent exposur es of endosulfan to freshwater invertebrates that may serve as prey for the SFGS. As described in Section

196

### 5.2.1.2 , the Agency determined that based on th e exceedances of non-listed species acute and
chronic risk LOCs for freshwater invertebrates for all of the modeled scenarios assessed and the high probability of an indi vidual mortality occurrence usi ng both the highest and lowest acute RQ for freshwater invertebrates, there appears to be adequate lines of evidence to conclude there is a potential for direct effects to freshwater invertebrates as result of labeled
endosulfan use in California.

As discussed in Section 5.2.3.1 for direct effects on the SFGS, there does appear to be a potential for spatial overlap between SFGS distribution and cultivated/orchard/vineyard agricultural areas where endosulfa n could be used in the futu re, although overlap in current use patterns appears negligible. Therefore, ba sed on the potential future use of endosulfan in cultivated crop/orchard/vineyard areas of San Mateo County, ther e appears to be a reasonable potential for indirect effects on the SFGS from lo ss of freshwater inverteb rate prey items.

Terrestrial Invertebrates

RQ values representing exposures of endosulfan to terrestrial invertebrates that may serve as prey for the terrestrial-phase CRLF are also us ed to represent exposures of endosulfan to terrestrial invertebrates that may serve as prey for the SFGS. As described in Section 5.2.1.2

, the Agency determined that based on the fact that endosulfan is a highly efficacious broad spectrum insecticide, exceedances of the Ag ency’s interim LOC for listed terrestrial
invertebrates for all of the modeled scenarios as sessed, the high percentage of tested terrestrial invertebrate species that would be affected at the modeled EECs, th e high probability of an individual mortality occurrence based on the RQs for terrestrial invertebrates, there appears to be a reasonable potential for direct effects on terrestrial invertebrates from the labeled
endosulfan use in California.

As discussed in Section 5.2.3.1 for direct effects on the SFGS, there does appear to be a potential for spatial overlap between SFGS distribution and cultivated/orchard/vineyard agricultural areas where endosulfa n could be used in the futu re, although overlap in current use patterns appears negligible. Therefore, ba sed on the potential future use of endosulfan in cultivated crop/orchard/vineyard areas of San Mateo County, ther e appears to be a reasonable potential for indirect effects on the SFGS from lo ss of terrestrial invertebrate prey items.

Small Terrestrial Vertebrates RQ values representing exposures of endosulfan to small terrestrial vertebrates that may serve as prey for the terrestrial-phase CRLF are also used to represent exposures of endosulfan to terrestrial small terrestrial vertebrates that may serve as prey for the SFGS. Similarly, the Agency determined a reasonable potential exists for direct effects on birds (surrogate for terrestrial phase amphibians) based on exposur e to food items receiving direct deposition from endosulfan application (i.e., T-RE X, T-HERPS modeling); consumption of contaminated aquatic prey (i.e., KABAM bi oaccumulation modeling), and consumption of contaminated terrestrial prey (i .e., earthworm fugacity modeling; Section 5.2.1.1 ).

As discussed in Section 5.2.3.1 for direct effects on the SFGS, there does appear to be a potential for spatial overlap between SFGS distribution and cultivated/orchard/vineyard

197

### agricultural areas where endosulfa n could be used in the futu re, although overlap in current use patterns appears negligible. Therefore, ba sed on the potential future use of endosulfan in cultivated crop/orchard/vineyard areas of San Mateo County, ther e appears to be a reasonable potential for indirect effects on the SFGS from loss of small terrestrial vertebrate prey items.

5.2.3.3 Indirect Effects ( via Habitat Effects )

SFGS inhabit areas near densely vegetated ponds and in open hillsides where it can sun, feed, and find cover in rodent burrows. It forages extensively in aquatic habitats. Fresh-water
habitats including natural and manmade (e.g. stock) ponds, slow moving streams, vernal pools and other ephemeral or permanent water bod ies which typically s upport inundation during
winter rains and hold water for a minimum of 12 weeks in a year of average rainfall and upland habitats within 200 ft of the mean high water mark of such aquatic habitat.

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants Aquatic plants serve several important functi ons in aquatic ecosystems such as primary production (non-vascular, vascular) and refugia structure (vascular plants). Rooted plants help reduce sediment loading and provide stability to nearshore areas and lower streambanks. In addition, vascular aquatic plants are important as attachme nt sites for egg masses of aquatic species.

Terrestrial plants serve several important habita t-related functions for the SFGS. In addition to providing habitat and cover for invertebrate and vertebra te prey items of the SFGS, terrestrial vegetation also pr ovides shelter for the SFGS and cover from predators while foraging. Terrestrial plants also provide ener gy to the terrestrial ecosystem through primary production. Upland vegetation in cluding grassland and woodl ands provides cover during dispersal. Riparian vegetation helps to mainta in the integrity of a quatic systems by providing bank and thermal stability, serving as a buffe r to filter out sediment, nutrients, and contaminants before they reach the wate rshed, and serving as an energy source.

As noted in Section 5.2.1.3, no data are available to relia bly, quantitatively evaluate the effects and the potential risks of endosulfan to vascular aquatic plants. No incidents have been reported to the Agency that involve any aquatic plants, despite that it is regularly directly applied on or near a very wide variety of ag ricultural plants. Only one reported incident involved plants and this was clas sified as ‘possible,’ but the plant species wa s not identified ( Section 4.4 and Appendix L ). No data on the effects of endosulfan on terrestrial plants were considered acceptable for quantitative use in this risk assessment. Based on efficacy studies, available information i ndicates that agricultural crops are not adversely affected by endosulfan use rates that are associated with pe st control. This, in conjunction with the
insecticidal mode of ac tion of endosulfan, suggests that terres trial plants may not be sensitive to endosulfan compared to aquatic and terrestria l animals. However, use of efficacy studies can be confounded by lack of experimental controls, multiple stressors (pesticide and insect pest), and plant species that may not be re presentative of those upon which the SFGS may depend. Although effects to aquatic and terrestrial plants cannot be quantified due to the lack of data, the available lines of evidence provide no compelling reason to believe that there is a

198

### potential for indirect effects to the SFGS from loss of plant food items as result of labeled
endosulfan use in California.

5.2.4 Salt Marsh Harvest Mouse

5.2.4.1 Direct Effects

Endosulfan is currently register ed for numerous diverse agricu ltural uses that span a large variety of geographical regions throughout the entire stat e of California ( Figure 2.6 and Figure 2.5 ). Therefore, there is the potential for endosulfan use across the state to spatially and temporally coincide with the SMHM breeding season.

The SMHM is a small, mostly nocturnal rodent that lives in tidal and diked salt marshes, only around the San Francisco Bay and its tributarie s. SMHM depend on dense, perennial cover and prefer habitat in the middle and upper part s of the marsh dominated by pickleweed and peripheral halophytes as well as similar vegetatio n in diked wetlands adjacent to the Bay. Salt marsh harvest mice are cover-dependent spec ies and only live under thick vegetation. Salt marsh harvest mice use pickleweed ( Salicornia virginica ) as their primary/pr eferred habitat as long as they have non-submerged, salt-tolerant vegetation for escape duri ng the highest tides. Their diet consists of seeds, grasses, forbs and insects.

Temporal and Spatial Overlap

The SMHM breeds from spring through the fall a nd there is strong poten tial for periods of breeding activity to overlap temporally with peak usage of endosulfan from May through September ( Figure 5.1 ). While male SMHM are descri bed as reproductively active from April through September, with some active throughout the ye ar, female SMHM have a long breeding season that extends from as early as March to November. In general, the northern subspecies of SMHM breeds from May to Novemb er and the southern subspecies breeds from March to November. Despite the long breedi ng season, the SMHM is characterized as having a low reproductive potential, with each female typically having only one or two litters per year with an average litter size of about three or four.

Since pesticide use information is only availabl e at the county level, the degree that the SMHM actually coincides in the same or sim ilar locations cannot be precisely determined. The spatial overlap of endosulfan use and SMHM distribution is summ arized at the county
level in Table 5.7 and Figure 5.7 ). Approximately 1.25% of endosulfan use (1,120 lbs) is applied in counties in which the SMHM occurs. These counties represent approximately 66% of the SMHM range by county. Thus, the potential for direct effects to the SMHM appears to
be low based on current endosulfan use patterns. The potential for endosulfan to be transported long distances from the applic ation site could extend exposure well beyond current use areas, which appears to be most rele vant for SMHM occurrence sections in Solano County (where current cultivated crop areas are west of the occurrence sections). Refer to
Section 3.2.4.4 for more information on long-range transport of endosulfan. If cultivated crop/orchard/vineyard uses ar e considered areas of potentia l endosulfan use in the future, then

199

### a very small amount of spatial overlap can be observed relative to th e total area of SMHM occurrence sections ( Figure E.3 of Appendix E ).

Direct Exposure: Deposition on Forage Items

Direct exposure of the SMHM and the resulti ng risks in terrestrial environments were evaluated based on dose- and dietary-based EEC s estimated using two approaches: (1) T-REX for foliar spray applications and (2) fugacity modeling for predicting endosulfan contamination of terrestrial prey. For dose- based exposure calculations, a body weight of 15 g was used for small mammals which correspond to the body weight of the SHMH mouse (8- 14 g). All estimated EECs ( i.e. , EECs for short grass, tall gra ss, broadleaf plants/small insects, fruits/pods/seeds/large insects) were considered relevant for evaluation of direct effects
because the SMHM has been known to feed on leaves, seeds, plant stems, insects, and

grasses.

Based on surrogate toxicity data (LD 50 

### =10 mg/kg-bw and NOAEL = 15 mg/kg-diet), the maximum allowable application rate (1 appli cation, 2.5 lbs a.i./acre/ap plication), the foliar dissipation half-life of 4 days for endosulfa n from Willis and McDowell (1987), and upper bound Kenaga values from T-REX, there is a po tential for direct a dverse effects on SMHM individuals from foliar spray applic ations of endosulfan in CA (see Table 5.4 ). Although EECs for small mammals feeding on short grass yi eld the highest risk estimates, it appears that the potential impact of endosulfan use to the SMHM potentially extend beyond those feeding on short grass.

For spray applications of endosulfan, the dose-based acute RQs for 15 g mammal range from 5.21 to 26.03, from 2.39 to 11.93, from 2.93 to 14.64, and from 0.33 to 1.63 for the short grass, tall grass, broadleaf pl ants/small insects, and fruits/pods/seeds/large insects dietary categories, respectively ( Table 5.4 ).For acute dose-based RQs, all modeled scenarios (N=20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ> 0.1) for mammals that feed on short grass, tall grass, broadleaf plants/small insects, a nd fruits/pods/seeds/large
insects.

The dose-based chronic RQs ranged from 69.41 to 347.04, from 31.81 to 159.06, from 39.04 to 195.21, and from 4.34 to 21.69, for the short grass, tall grass, broadleaf plants/small insects, and fruits/pods/seeds/large insect dietary categories, respectively ( Table 5.4 ). For chronic dose-based RQs, all modeled scenarios (N=20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short grass, tall grass, broadleaf plants/small insects, and fru its/pods/seeds/large insects.

The dietary-based chronic RQs range from 8 to 40.00, from 3.67 to 18.33, from 4.50 to 22.50, and from 0.50 to 2.50, for the short grass, tall grass, broadleaf plan ts/small insects, and fruits/pods/seeds/large insects di etary categories, respectively ( Table 5.4 ). For chronic dietary-based RQs, all modeled scenarios (N=20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short grass, tall grass, and broadleaf plants/small insects. Thirteen out of 20 modeled scenarios resulted in an exceedance of the Agency’s chronic risk LOC (RQ ≥ 1) for mammals that feed on fruits/pods/seeds/large

200

### insects. RQs exceed the Agency’s acute listed species LOC (RQ> 0.1) and chronic risk LOC (RQ> 1) for mammals for foliar spra y applications of endosulfan.

Direct Exposure: Contaminated Soil

In addition to the consumption of food items subject to direct de position of endosulfan applied to agricultural areas discussed above, th e potential exists for direct effects to the
SMHM via soil contaminated with endosulfan. In order to explore the potential exposures of
SMHM to total residues of endosulfan that have accumulated in earthworms inhabiting endosulfan-treatment sites, a simple fugacity approach was employed to estimate endosulfan
concentrations in earthworms and subse quent exposures to the SMHM consuming earthworms. Pesticide applicati on rates, the foliar di ssipation rate, toxici ty data, body weights and consumption weights were identical to that used for the mammalian T-REX modeling
described in Section 5.1. A log Kow for endosulfan of 4.76 was used based on the weighted mean Kow for alpha and beta isomers of 70:30, respectively (MRID 414215-01). A soil distribution coefficient (Kd) of 69 cm 3 

### /g was used based on the weighted mean Kd for alpha and beta isomers of 70:30, re spectively (MRID 414129-06). This Kd represents the lower range of four Kd values availa ble for different soils in this study, wherein an upper range of
Kd were 320 and 428 cm 3 

### /g for alpha and beta endosulfa n was reported. Using the lower value for Kd represents a conservative assumpti on since for a given Kow, concentrations in earthworms increase with decreasing Kd. For this analysis, the two crop exposure scenarios that produce the highest and lo west dietary EECs (Citrus/Fruits and Eggplant, respectively) were evaluated in order to provide informa tion on the overall range of potential risks to SMHM consuming contaminated earthworms. Risks were evaluated for the 15g mammalian size classes ( Table 5.23 ; the 1000g size class was included fo r evaluating risk to the SJKF
which is discussed in Section 5.2.5). Details on this approach are provided in Appendix N

. Results presented in Table 5.23 indicate dose-based RQs exceed the Agency’s listed acute a LOC for 15g mammal even when using the expo sure scenario with the lowest soil EECs (eggplant). Furthermore, chronic dose- and dietary-based RQs exceed the chronic LOC for the eggplant exposure scenario.

Table 5.23 Estimated concentrations of total endosulfan in earthworms and mammalian risk quotients for two crop exposure scenarios

Eggplant Citrus

Results 15g (6) 1000g (6) 15g (6) 1000g (6)

Dose-based EEC (1) (mg/kg-bw) 61.2 9.8 212.7 34.1
Acute Dose-based RQ (2,3) 2.8 1.3 9.7 4.4
Chronic Dose-based RQ (2,4) 37.1 17.0 129.0 59.08
Diet-based EEC (1) (ppm w.w. in earthworm) 64 64 Chronic Dietary-based RQ (2,5) 4.3 4.3 (1) Based on fugacity modeling for earthworm using total endosulfan concentrations in soil and soil pore water of 22.4 and 0.183 g/m 3 , respectively for Citrus and 5.3 and 0.066 g/m 3 , respectively, for Eggplant exposure scenarios; See Appendix N for details. (2) RQ values in bold exceed the acute listed sp ecies LOC of 0.1 or the chronic LOC of 1.0 (3) Acute dose-based RQs calculated using the dose-based EECs and adjusted, acute dose-based



### 201Table 5.23 Estimated concentrations of total endosulfan in earthworms and mammalian risk quotients for two crop exposure scenarios

Eggplant Citrus toxicity values of 21.98 and 7.69 mg/kg-bw for the 15g and 1000g mammal, respectively. Unadjusted LD50 = 10 mg/kg-bw based on rat (MRID 00038307). (4) Chronic dose-based RQs calculated using dose-based EECs and an adjusted, dose-based chronic NOAEC of 1.65 mg/kg-d for 15g mammals and 0.58 for 1000g mammals; Unadjusted dosebased NOAEC for rat calculated as 0.75 mg/kg-bw for the rat(MRID 00148264) (5) Chronic diet-based RQs calculated using diet-based EECs and a mammalian dietary NOAEC of 15 ppm for rat (MRID: 00148264) (6) 15 g mammal used for estimating risks to SMHM; 1000g used for SJKF



### In conclusion, based on: 1. exceedances of the Agency’s list ed species acute risk LOC (RQ> 0.1) and chronic risk LOC (RQ> 1) for small mammals feeding on a variety of terrestrial food items for the various endosulfan application scenarios considered, 2. the high probability of an individual mo rtality occurrence based on the highest acute RQ for mammals (~1 in 1; Table 5.12 ), 3. LOC exceedences via consumption of earthworms via soil contamination ( Table
5.23 ), evidence of similar sensitivity of rats and mice to endosulfan ( Section 4 and Appendix K ), 4. a significant degree of temporal overlap w ith endosulfan applications w/ SHMH life stages, and 5. some spatial overlap between SMHM occurrence sections and cultivated/ orchard/vineyard crop use areas;

it appears there is a potential for direct effects to the SMHM as result of labeled endosulfan use in California, although this potential is likely to be limited to small areas spatially.

5.2.4.2 Indirect Effects ( via Reductions in Prey Base )

Potential forage items of the SMHM include l eaves, seeds, plant stems, and insects, although
seasonal variation has been observed in SMHM stomach contents with fresh green grasses more prevalent in the winter, and pickleweed and saltgrass dominating dur ing the rest of the

year.

Terrestrial Invertebrates

RQ values representing exposures of endosulfan to terrestrial invertebrates that may serve as prey for the terrestrial-phase CRLF are also us ed to represent exposures of endosulfan to terrestrial invertebrates that may serve as prey for the SMHM. As described in Section
5.2.1.2 , the Agency determined that based on the f act that endosulfan is a highly efficacious broad spectrum insecticide, exceedances of th e Agency’s interim LOC for listed terrestrial
invertebrates for all of the modeled scenarios as sessed, the high percentage of tested terrestrial invertebrate species that would be affected at the modeled EECs, and the high probability of an individual mortality occurrence based on the RQ s for terrestrial invertebrates, there appears

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### to be a reasonable potential for direct eff ects on terrestrial invertebrates from the labeled
endosulfan use in California.

However, as discussed previously in Section 5.2.4.1 for directs effects on SMHM, the potential overlap of current and future endosul fan use patterns with the occurrence of the SMHM (and by extension, its terrestrial inverteb rate prey) appears to be very small. Nevertheless, in these areas of spatial overla p, there does appear to be sufficient lines of
evidence for a direct effect on the SMHM throu gh reductions in terrestri al invertebrate prey, assuming the sensitivity of tested terrestrial invertebrates is similar to the terrestrial invertebrate prey being consumed by the SMHM.

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants

As noted in Section 5.2.1.3, no data are available to relia bly, quantitatively evaluate the effects and the potential risks of endosulfan to vascular aquatic plants or terrestrial plants. Only one reported incident i nvolved plants (I014 404-001, June 1, 1990 in Washington State), but no damage was reported and the incident cl assified only as ‘po ssible’ (i.e., exposure concentrations were not documented). Although effects to vascular a quatic and terrestrial plants cannot be quantified due to the lack of data, the availa ble lines of evidence provide no compelling reason to believe that there is a potential for indirect effects to the SMHM from loss of plant food items as result of la beled endosulfan use in California.

5.2.4.3 Indirect Effects ( via Habitat Effects )

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants 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 structur e as attachment sites and refugia for many aquatic invertebrates, fish, a nd juvenile organisms, such as fish and frogs. In addition, vascular plants also provide primary produc tivity and oxygen to the aquatic ecosystem. Rooted plants help reduce sediment loading and provide stability to ne arshore areas and lower streambanks. In addition, vascular aquatic plan ts are important as attachment sites for egg masses of aquatic species.

Terrestrial plants serve several important habita t-related functions for the SMHM. In addition to providing habitat and cover fo r invertebrate prey items of the SMHM, terrestrial vegetation also provides nesting material, shelter, and c over from predators while foraging. Terrestrial plants also provide energy to the terrestr ial 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 sedi ment, nutrients, and contaminants before they reach the watershed, and serving as an energy source.

As stated in Section 5.2.1.4 covering the evaluation of potenti al indirect effects to the CRLF via habitat effects, a lthough effects to vascular aquatic and terrestrial plants cannot be quantified due to the lack of data, since th e RQs do not exceed the Agency’s LOC (1) for

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### aquatic non-vascular plants based on the most sensitive data available to the Agency, and because available lines of evidence provide no compelling reason to believe that endosulfan will affect any type of plants to the extent th at it would affect the habitat integrity of the SMHM, labeled endosulfan use in California ap pears not likely to in directly affect the SMHM via impacts to habitat and/or primary production. Please refer to Section 5.2.1.4 for additional
discussion and characterization of potential risks to plants that may be foraged upon by the
SMHM.

Small Terrestrial Vertebrates

SMHM do not burrow, but some winter nests may be constructed in burrows and small
crevices. SMHM nests are described as mini mal, and the SMHM may build over old birds’ nests or use nests built by Suisun shrews, afte r the young shrews have dispersed. Therefore, the potential for indirect effects to the SMHM via affects to small mammals and birds that may help to provide suitab le habitat was evaluated.

RQ values representing exposures of endosulfan to small mammals that may serve as prey for the terrestrial-phase CRLF, are also used to represent exposures of endosulfan to small mammals that may help to provide suitable ha bitat (nests) for the SMHM. As described in
Section 5.2.4.1 for direct effects on the SMHM, the Agency determined that a potential for
direct effects to the SMHM exits as result of labeled endosulfan use in California, although this potential is likely to be limited to small areas spatially. The Agency further determined that a potential for direct e ffects of endosulfan use exists on birds, as described for the terrestrial phase CRLF ( Section 5.2.1.1 ). Therefore, the same potential exists for habitat
modification due to loss of mammalian a nd avian-created nesting sites.

5.2.5 San Joaquin Kit Fox

5.2.5.1 Direct Effects

Endosulfan is currently register ed for numerous diverse agricu ltural uses that span a large variety of geographical regions throughout the en tire state of California. Therefore, there is the potential for endosulfan use acro ss the state to spatially and temporally coincide with the SJKF breeding season.

SJKF occupies a variety of habitats , including grasslands, scrublands ( e.g ., chenopod scrub and sub-shrub scrub), vernal pool areas, oak woodland, alkali meadows and playas, and an agricultural matrix of row crops , irrigated pastures, orchards , vineyards, and grazed annual grasslands. Kit foxes dig thei r own dens, modify and use thos e already constructed by other animals (ground squirrels, badgers, and coyotes), or use human-made structures (culverts, abandoned pipelines, or banks in sumps or roadbeds). They move to new dens within their home range often (likely to avoid predation by coyotes). Th e SJKF forages in California prairie and Sonoran grasslands in the vicinity of freshwater marshes and alkali sinks, where there is a dense ground cover of tall grasses and San Joaquin saltbush. Seasonal flooding in
such habitats is normal. It feeds on small animals including blacktailed hares, desert cottontails, mice, kangaroo rats, squirrels, birds, lizards, insects and grass. The San Joaquin

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### kit fox satisfies its moisture requirements fr om prey and does not depend on freshwater

sources.

Temporal and Spatial Overlap

The breeding season of the SJKF is from late December – March, with a gestation period of 48 to 52 days. Litters are born February - late March. Pups emerge from their dens at about 1- month of age and may begin to disperse afte r 4 – 5 months usually in Aug. or Sept. Pup dispersal coincides with the peak endosulf an application in August through September ( Figure 5.1 ).

The SJKF inhabits grasslands in the San Jo aquin Valley and easter n Bay Area counties of California. Since pesticide use information is only available at the county level, the degree that the SJKF and endosulfan actually coincide cannot be precisely determined. The spatial overlap of endosulfan use and SJKF distributi on is summarized at the county level in Table
5.7

. Approximately 80% of endosulfan use (71,104 lbs) is applied in counties in which the
SJKF occurs. These counties re present approximately 73% of the SJKF range by county. Examination of the overlap of SJKF occu rrence sections and distribution records ( Figure E.4 of Appendix E ) with cultivated crop, orchard and vine yard areas suggests a moderate amount of spatial overlap with potential endosulfan use areas.

Direct Exposure

Direct exposure of the SJKF and the resulting ri sks in terrestrial envir onments were evaluated based on dose- and dietary-based EECs estimated using two approaches ( i.e., T-REX for foliar spray applications and using fugacity-b ased modeling for insectivorous wildlife). All estimated EECs ( i.e. , EECs for short grass, tall grass, broadleaf plants/small insects, fruits/pods/seeds/large insects) were considered relevant for evaluation of direct effects
because the SJKF has been known to feed on insects and grasses. A mammalian body weight of 1000g was modeled based on the adult size of the kit fox.

Based on surrogate toxicity data (LD 50 

### =10 mg/kg-bw and NOAEL = 15 mg/kg-diet), the maximum allowable application rate (1 appli cation, 2.5 lbs a.i./acre/ap plication), the foliar dissipation half-life of 4 days for endosulfa n from Willis and McDowell (1987), and upper bound Kenaga values from T-REX, there is a po tential for direct a dverse effects on SJKF individuals from foliar spray applic ations of endosulfan in CA ( Table 5.4 ).

For spray applications of endosulfan, the dose-based acute RQs range from 2.38 to 11.92, from 1.09 to 5.46, from 1.34 to 6.70, and from 0.15 to 0.74 for the short grass, tall grass, broadleaf plants/small insects, and fruits/pod s/seeds/large insect dietary categories, respectively ( Table 5.4 ). For acute dose-based RQs, all m odeled scenarios (N=20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ> 0.1) for mammals that feed on short grass, tall grass, broadleaf plants/small insects, and fruits/pods /seeds/large insects.

The dose-based chronic RQs ranged from 31.78 to 158.90, from 14.57 to 72.83, from 17.88 to 89.38, and from 1.99 to 9.93, for the short grass, tall grass, broadleaf plants/small insects, and

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### fruits/pods/seeds/large insect di etary categories, respectively ( Table 5.4 ). For chronic dosebased RQs, all modeled scenarios (N=20) result ed in an exceedance of the Agency’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short grass, tall grass, broadleaf plants/small insects, and fru its/pods/seeds/large insects.

The dietary-based chronic RQs range from 8 to 40.00, from 3.67 to 18.33, from 4.50 to 22.50, and from 0.50 to 2.50, for the short grass, tall grass, broadleaf plan ts/small insects, and fruits/pods/seeds/large insects di etary categories, respectively ( Table 5.4 ). For chronic dietary-based RQs, all modeled scenarios (N=20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ ≥ 1) for mammals that feed on short grass, tall grass, and broadleaf plants/small insects. Thirteen out of 20 modeled scenarios resulted in an exceedance of the Agency’s chronic risk LOC (RQ ≥ 1) for mammals that feed on fruits/pods/seeds/large insects. Therefore, RQs for exceed the Agency’s acute listed species LOC (RQ> 0.1) and chronic risk LOC (RQ> 1) for mammals (see Table 5.4 ) for foliar spray applications of
endosulfan.

As described in Section 5.2.4.1 , the potential exists for direct effects to insectivorous wildlife (including SJKF) via soil contaminated with en dosulfan. In order to explore the potential exposures of SJKF to total residues of endos ulfan that have accumulated in earthworms inhabiting endosulfan-treatment sites, a simple fugacity approach was employed to estimate
endosulfan concentrations in earthworms and su bsequent exposures to the SJKF consuming
earthworms. Additional de scription of this appr oach is provided in Appendix N . Results presented in Table 5.23 indicate dose-based RQs exceed the Ag ency’s listed acute a LOC for a 1000g mammal even when using the exposur e scenario with the lowest soil EECs (eggplant). Furthermore, chronic dose- a nd dietary-based RQs for a 1000g mammal exceed the chronic LOC for the eggpl ant exposure scenario.

In conclusion, the Agency determines that based on: 1. Exceedances of the Agency’s list ed species acute risk LOC (RQ> 0.1) and chronic risk LOC (RQ> 1) for large mammals feeding on a vari ety of terrestrial food items for the various endosulfan application scenarios considered, 2. The high probability of an individual mortality occurrence based on the highest acute RQ for mammals (~1 in 1; Table 5.12 ), 3. LOC exceedences via consumption of earthworms via soil contamination ( Table 5.23 ),
and 4. A moderate degree of spatia l and temporal overlap of SJ KF occurrence and potential endosulfan use areas,

It appears there is a pot ential for direct effects to the SJKF as result of labeled endosulfan use
in California.

5.2.5.2 Indirect Effects ( via Reductions in Prey Base )

Potential forage items of the SJKF include small mammals, grasses, and insects.

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### Terrestrial Invertebrates

RQ values representing exposures of endosulfan to terrestrial invertebrates that may serve as prey for the terrestrial-phase CRLF, CTS, SFGS SMHM are also used to represent exposures of endosulfan to terrestrial invertebrates that may serve as prey for the SFKF. As described in
Section 5.2.1.2 , the Agency determined that based on the fact that endosulfan is a highly efficacious broad spectrum insecticide, exceedan ces of the Agency’s interim LOC for listed
terrestrial invertebrates for all of the modeled sc enarios assessed, the high percentage of tested terrestrial invertebrate species that would be affected at the modeled EECs, and the high probability of an individual mortality occurrence based on the RQs for terrestrial invertebrates, there appears to be a reasonable potential for direct effects on terrestrial
invertebrates from the labeled endosulfan use in California. Furthermore, there appears to be a moderate amount of spatial overlap between SJKF occurrence and both current and potential future endosulfan use areas, as described in Section 5.2.5.2 . Therefore, the Agency
determines that there are sufficient lines of ev idence for indirect effect on the SJKF through reductions in terrestrial invertebrate prey, a ssuming the sensitivity of tested terrestrial
invertebrates is similar to the terrestrial i nvertebrate prey being consumed by the SLKF.

Small Mammals

RQ values representing exposures of endosulfan to small mammals that may serve as prey for the terrestrial-phase CRLF, are also used to represent exposures of endosulfan to small mammals that may help to provide prey for the SJKF. As described in Section 5.2.1.2 for the terrestrial-phase CRLF, the Agency determin ed that based on the exceedances of the Agency’s listed species acute risk LOC and chronic risk LOC for small mammals feeding on a variety of terrestrial food items for the various endosulfan seed, spray, and granular application scenarios considered, the high proba bility of an individual mortality occurrence based on the highest acute RQ for mammals (~1 in 1), and the relative insensitivity of risk
conclusions to selection of le ss conservative acute and chroni c endpoints, there are adequate lines of evidence for potential di rect effects on mammals as a re sult of labeled endosulfan use in California. Furthermore, there appears to be a moderate amount of spatial overlap between SJKF occurrence and both current and potential fu ture endosulfan use areas, as described in
Section 5.2.5.2 . Therefore, the Agency determines that there are sufficient lines of evidence for indirect effect on the SJKF through reduc tions in small mammalian prey, assuming the sensitivity of tested mammals is similar to the mammalian prey being consumed by the SLKF.

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants

As noted in Section 5.2.1.3, no data are available to relia bly, quantitatively evaluate the effects and the potential risks of endosulfan to va scular aquatic plants or terrestrial plants. No incidents have been reported to the Agency that involve any plants (all terrestrial plants), and none have reliably linked endosulfan to the observed effects with a certainty index of “probable” or higher, despite that it is regularly directly applied on or near a very wide variety of agricultural and home garden plants. Ther efore, although effects to vascular aquatic and terrestrial plants cannot be quantified due to the lack of da ta, the available lines of evidence

207

### provide no compelling reason to believe that ther e is a potential for indirect effects to the SJKF from loss of plant food items as result of labeled endosulfan use in California.

5.2.5.3 Indirect Effects ( via Habitat Effects )

Aquatic (Vascular and Non-vasc ular) and Terrestrial Plants 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 structur e as attachment sites and refugia for many aquatic invertebrates, fish, a nd juvenile organisms, such as fish and frogs. In addition, vascular plants also provide primary produc tivity and oxygen to the aquatic ecosystem. Rooted plants help reduce sediment loading and provide stability to ne arshore areas and lower streambanks. In addition, vascular aquatic plan ts are important as attachment sites for egg masses of aquatic species.

Terrestrial plants serve several important habita t-related functions for the SJKF. In addition to providing habitat and cover fo r invertebrate prey terrestrial plants also provide energy to the terrestrial ecosystem through primary produc tion. Upland vegetation including grassland and woodlands provides cover during dispersal. Riparian vegetation helps to maintain the integrity of aquatic systems by providing bank and thermal stability, serving as a buffer to filter out sediment, nutrients, and contaminants before they reach the watershed, and serving

as an energy source.

As stated in Section 5.2.1.3 covering the evaluation of potenti al indirect effects to the CRLF via habitat effects, a lthough effects to vascular aquatic and terrestrial plants cannot be quantified due to the lack of data, since th e RQs do not exceed the Agency’s LOC (1) for aquatic non-vascular plants based on the most sensitive data available to the Agency, and because available lines of evidence provide no compelling reason to believe that endosulfan will affect any type of plants to the extent th at it would affect the habitat integrity of the SJKF, labeled endosulfan use in California appears not to indirectly affect the SJKF via impacts to habitat and/or primary production.

5.2.6 Bay Checkerspot Butterfly

5.2.6.1 Direct Effects

The BCB’s life cycle is closely tied with the biology of its host pl ants. The host plants germinate anytime from early October to late December and senesce from early April to mid May, and most of the active parts of the BCB life cycle also occur during this time (see Figure 5.9 ). The BCB reproduces once and dies within a single year. Adults emerge from pupae, feed on nectar, mate and lay eggs during a flight season that lasts 4 to 6 weeks from late February to early May. While females normally (although not always) only mate once, males emerge up to 10 days prior to the emer gence of females and may mate several times before dying. Adults of both sexes live on average for 10 days (with a maximum adult life span of over 3 weeks reported). Females lay up to 5 egg masses (250 eggs/mass) typically in

208

### March and April. Eggs are deposite d primarily near the base of dwarf plantain plants, and less commonly on purple owl’s-clover and exserted paintbrush.

Larvae hatch from eggs in roughly 10 days and grow to the 4 th 

### instar in about two weeks. Once reaching the 4 th 

### instar, the larvae then spend a pe riod of dormancy (diapause) under rocks or in soil cracks that lasts through the su mmer. The larvae resume activity with the start of the rainy season and the germination of dwar f plantain plants. The post-diapause larvae are more mobile than the pre-diapause larvae and ma y travel tens of mete rs in search of food and/or warm microclimates to bask or pupate in. Larvae pupate, with the pupae suspended few meters above the ground on vegetation, once they reach a weight of 300 - 500 milligrams. Adults emerge within 15 to 30 days dependi ng on thermal conditions, although there is some evidence that a few larvae in very dry years may enter into a second diapause and complete their development the sec ond spring after hatching.

Figure 5.9 General Annual Life-History Parameters for the BCB



### As previously discussed in Section 5.2.1.1 , endosulfan is currently registered for a wide variety of agricultural in crops, orchards, and nursery (only one non-agricultural use: ear tags for cattle), which span a large variety of us e sites and geographical regions throughout the
entire state of California and allow for the potential for almost year-round use (see Figure
5.1 ). Therefore, there is the potential for endosul fan use in any given ar ea across the state to spatially and temporally coincide with all of th e critical life-stages of the BCB, and disrupt its life-cycle at various points. Ho wever, during the mont hs of peak usage August and September ( Figure 5.1 )
, larvae are in their dormancy stage (see Figure 5.9 ).

For the purposes of evaluating direct exposur e and effects to the BCB, larvae for the BCB were considered ‘small insects’ in this assessment, while the adults of this species were considered ‘large insects’. Ther efore, the potential fo r direct exposure and effects specifically to the BCB resulting from endosulfan spray appl ications was evaluated by considering the
lowest available acute contact toxicity endpoint for terrestria l invertebrates along with the TREX estimated EECs for small (broadleaf plan ts/small insects dietary category) and large (fruits/pods/seeds/large insect s dietary category) insects. Based on the beet webworm ( Pyrausta sticticalis ) toxicity data (LD50 = 0.15 ug a.i./g ) the RQs for small insects ranged from 547 to 2250, and those for large insects from 50 to 250).

RQ values representing exposures of endosulfan to terrestrial invertebrates that may serve as prey for the terrestrial-phase CRLF, are also us ed to represent direct exposures of endosulfan
to the BCB. As described in Section 5.2.1.2 , the Agency determined that based on the fact that endosulfan is a highly efficacious broad spectrum insecticide, the exceedances of the Agency’s interim LOC for listed terrestrial i nvertebrates for all of the modeled scenarios assessed (for both large (adult BCB) and small ( BCB larvae) insects), and the high probability of an individual mortality occurrence ba sed on the highest acute RQ for terrestrial

209

### invertebrates (~1 in 1), it appe ars that there are adequate lines of evidence to conclude that there is a potential for direct effects to the BCB as result of labeled endosulfan use in
California.

However, it should be noted that th e spatial distribution of current average endosulfan use and
BCB distribution do not coincide (see Table 5.7 ; Figure 5.7 ). If cultivated crop, orchard and vineyard use areas are considered as regions of potential endosu lfan use in the future, then a substantial degree of overlap between BCB occurrence, its critical habitat and where endosulfan use could occur ( Figure E.5 of Appendix E ). Furthermore, there is potential for endosulfan to be transported long dist ances from the application sites ( Section 3.2.4.4 ).

5.2.6.2 Indirect Effects (via Reduction in Prey Base & Habitat Effects)

The primary diet for the BCB larvae are dwarf pl antain plants (although they may also feed on purple owl’s-clover or exserted paintbrush if the dwarf plantains senesce before the larvae pupate). Adults feed on the nectar of a variety of plants found in association with serpentine grasslands [ e.g ., California goldfields, tidy-tips, desert pa rsley, scytheleaf ( Allium falcifolium ), sea muilla ( muilla maritime ), false babystars ( Linanthus androsaceus ), and intermediate fiddleneck ( Amsinckia intermedia )].

In addition to serving as the primary dietary it em of the BCB, terrestria l plants serve several important habitat-related functions that are described below in Section 5.2.6.3 in detail with regards to critical habitat. Therefore, the poten tial for indirect effect s to the BCB via loss of terrestrial plant food items and impacts to habitat and/or primary production was considered.

Terrestrial Plants

For the purposes of this assessment, the potentia l for indirect effects to the BCB via loss of terrestrial plant food items and impacts to ha bitat and/or primary production was assessed by considering effects to terres trial plants. As noted in Section 5.2.1.3, there were no data to reliably quantitatively evaluate the effects and the potential risk s of endosulfan to terrestrial plants. However, aquatic non-vascular plants are not particularly se nsitive to endosulfan,
endosulfan has a neural toxic mode of acti on, and no studies demons trating significant adverse effects of endosulfan to any vascular aquatic or terrestri al plant have been identified in the open literature. The only terrestrial plan t information comes from studies of single application to food crops to determine the effi cacy of endosulfan for the control of insect pests. By design, the exposure concentrations for the control of insect pe sts are intended not to harm the crop plants. However, these studies are only available for herbaceous plants and none for woody plants. In addition, since 1970 no eco logical incidents have been reported to the Agency that involved any documented harm to either aquatic or terrestrial plants, despite that it is regularly directly applied on or near a very wide variety of agricultural and home garden plants. Therefore, although effects to terrestrial plants cannot be quantified due to the lack of data, the available lines of evidence pr ovide no compelling reason to believe that there is a potential for indirect eff ects to the BCB via loss of terrestri al plant food items and impacts to habitat and/or primary pr oduction as result of labeled e ndosulfan use in California.

5.2.6.3 Modification to Design ated Critical Habitat

The primary constituent elements (PCEs) of the BCB include:

210

### • 

### The presence of annual or perennial grasslands with little to no ove rstory that provide north/south and east/west slopes with a tilt of more than 7 degrees for larval host plant survival during periods of atypical weather (e.g., drought).

• 

### The presence of the primary larv al host plant, dwarf plantain ( Plantago erecta ) (a dicot) and at least one of the secondary host plants, purple owl' s-clover or exserted paintbrush, are required for reproduction, feeding, and larval development.

• 

### The presence of adult nectar sources for feeding.

• 

### Aquatic features such as wetlands, springs, seeps, streams, lakes, and ponds and their associated banks, that provide moisture during periods of spring drought; these features can be ephemeral, seasonal, or permanent.

• 

### Soils derived from serpentinite ultramafic rock (Montara, Climara, Henneke, Hentine, and Obispo soil series) or similar soils (Inks, Candlestick, Los Gatos, Fagan, and Barnabe soil series) that provide areas w ith fewer aggressive, nonnative plant species for larval host plant a nd adult nectar plant su rvival and reproduction.

• 

### The presence of stable holes and cracks in the soil, and surface rock outcrops that provide shelter for the larval stage of the bay checkerspot butterfly during summer diapause.

For the purposes of this assessment, the potentia l for indirect effects to the BCB as result of effects to the PCEs of its designated critical habitat is assessed by considering effects to terrestrial plants. Similar to what was noted in Section 5.2.6.2 above, in which the potential
for indirect effects to the BCB via loss of terrestrial plant f ood items and impacts to habitat and/or primary production was assessed, although effects to terrestrial plants cannot be quantified due to the lack of data, the Agency concludes that the we ight-of-evidence suggests that effects to terrestrial plan ts as a result of labeled endos ulfan use in California are not expected to the extent that there will be m odification of BCB designate d critical habitat.

5.2.7 Valley Elderberry Longhorn Beetle

5.2.7.1 Direct Effects

The VELB “feeds on at least one species of elderberry ( Sambucus ) and perhaps as many as three elderberry taxa” including S. glauca

, S. caerulea , and S. mexicana (USFWS, 1984). VELB adults consume elderberry foliage and possibly also the flowers whereas the “larvae are borers and feed on the soft pith in stems and roots of the elderb erry” (USFWS, 1984 and 2007 b; and LSA, 2004). The adults eat from when they emerge in the spring until about June when they begin to mate (Ca lifornia’s Endangered Insects).

The life cycle of the VELB is divided into four stages: egg, larva, pupa, and adult, and has been assumed to encompass two years, but re cent information from rearing experiments suggests that a one year cycle is possible, if not probable (Bar r, 1991). Female VELB lay their eggs singly or in small groups on live elderberry leaves, in crevices in the bark, at the stem/trunk junctions, or at the stem/petiole junctions of the elde rberry (Barr, 1991; California’s Endangered Insects; and Talley, no date). The firs t instar larvae are exposed on the surface of the shrub anywhere from a few minu tes to a day before they bore to the center of elderberry stems where they create a character istic feeding gallery in the pith at the center of the stem (Talley et al., 2006 and Barr, 1991) . The larvae develop for 1 or 2 years feeding

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### on pith (Talley et al., 2006), eventually creat ing a pupal chamber. In the pupal chamber, the larvae metamorphose into their pupae between December and April (Talley et al., 2006). Pupation is thought to take about one month and the adult may remain in the chamber for up to several weeks (Talley et al., 2006). The VELB adults typically emer ge at about the same time the elderberry flowers, between mid-Ma rch and mid-June” (USFWS, 1984 and Talley et al., 2006). The adults live for a few days to a few weeks between mid-March and early-June (Talley, no date and 2006; and USFWS, 1984). Ho wever, most records are for late-April to mid-May (Talley et al., 2006 and USFWS, 1984). During this period, the adults feed on elderberry leaves and possibly flowers, and reproduce within the canopy (Talley, no date and 2006). The females also lay their eggs during this period (USFWS, 2006) . The lifespan of the adult VELB is unknown; however, it is suspected that they die after reproducing (LSA, 2004).

As with the BCB, there is the potential for endos ulfan use in any given area across the state to temporally coincide with all of the critical li fe-stages of the BCB, and disrupt its life-cycle at various points. For the purposes of evaluating di rect exposure and effects to the VELB, larvae were considered ‘small insects’ in this assessment, while the adults of this species were considered ‘large insects’. Ther efore, the potential fo r direct exposure and effects specifically to the VELB resulting from endosulfan spray ap plications was evalua ted by considering the
lowest available acute contact toxicity endpoint for terrestria l invertebrates along with the TREX estimated EECs for small (broadleaf plan ts/small insects dietary category) and large (fruits/pods/seeds/large insects di etary category) insects. The RQ analysis for VELB is the same as evaluated previously for BCB ( Section 5.2.5 ). Therefore, as with BCB, it appears that there are adequate lines of evidence to conclude that there is a potential for direct effects to
the VELB as result of labeled endosulfan use in California. However, the VELB or its critical
habitat occurs in coun ties with less than 0.01% of the average endosulfan use in California from 2005-2006 ( Table 5.7 and Figure 5.7 ). When the cultivated crop, orchard, and vineyard agricultural uses are considered as potential area of future endosulfan use, then a moderate amount of spatial overlap with V ELB occurrence can be observed ( Figure E.6 of Appendix

E ). Furthermore, there is potential for endosul fan to be transported long distances from the application sites ( Section 3.2.4.4 ).

5.2.7.2 Indirect Effects ( via Reduction in Prey Base & Habitat Effects )

The VELB feeds on at least one species of elderberry ( Sambucus ) and perhaps as many as three elderberry taxa including S. glauca

, S. caerulea , and S. mexicana (USFWS, 1984). In addition to serving as the prim ary dietary item of the VELB, te rrestrial plants serve several important habitat-related functions that are described below in Section 5.2.5.2 in detail with regards to critical habitat. Ther efore, the potential for indirect effects to the VELB via loss of terrestrial plant food items and impacts to habitat and/or primary production was considered.

Terrestrial Plants

For the purposes of this assessment, the potential for indirect effects to the VELB via loss of terrestrial plant food items and impacts to ha bitat and/or primary production was assessed by considering effects to terres trial plants. As noted in Section 5.2.1.3, there were no data to reliably quantitatively evaluate the effects and the potential risk s of endosulfan to terrestrial plants. However, aquatic non-vascular plants are not particularly se nsitive to endosulfan,
endosulfan has a neural toxic mode of acti on, and no studies demons trating significant adverse effects of endosulfan to any vascular aquatic or terrestri al plant have been identified

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### in the open literature. The only terrestrial plan t information comes from studies of single application to food crops to determine the effi cacy of endosulfan for the control of insect pests. By design, the exposure concentrations for the control of insect pe sts are intended not to harm the crop plants. However, these studies are only available for he rbaceous plants and none for woody plants. In addition, since 1970 no eco logical incidents have been reported to the Agency that involved any documented harm to either aquatic or terrestrial plants, despite that it is regularly directly applied on or near a very wide variety of agricultural and home garden plants. Therefore, although effects to terrestrial plants cannot be quantified due to the lack of data, the available lines of evidence pr ovide no compelling reason to believe that there is a potential for indirect e ffects to the VELB via loss of terrestrial plant food items and impacts to habitat and/or primary production as result of labeled endosulfan use in California.

5.2.7.3 Modification to Design ated Critical Habitat

The primary constituent elements (PCEs) of the VELB include the presence of riparian elderberry trees during its entire life cycle. Fo r the purposes of this assessment, the potential
for indirect effects to the VELB as result of effects to the PC Es of its designated critical habitat is assessed by considering effects to terrestrial plants. Similar to what was noted in
Section 5.2.6.2 above, in which the potential for indirect effects to the VELB via loss of terrestrial plant food items and impacts to ha bitat and/or primary production was assessed, although effects to terrestrial plants cannot be qua ntified due to the lack of data, the Agency concludes that the weight-of-evid ence suggests that effects to te rrestrial plants as a result of
labeled endosulfan use in California are not expected to the extent that there will be modification of VELB designa ted critical habitat.

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# 6 Uncertainties

6.1 Exposure Assessment Uncertainties

6.1.1 Maximum Use Scenario

The screening-level risk assessment focuses on characterizing poten tial ecological risks resulting from a maximum use scenario, which is determined from labeled statements of maximum application rate and numbe r of applications with the s hortest time interval between applications. The frequency at which actual us es approach this maximum use scenario may be dependant on pest resistance, timing of applications, cultural practices, and market forces.

6.1.2 Aquatic Exposure Modeling of Endosulfan

The standard ecological water body scenario (EXAMS pond) used to calculate potential aquatic exposure to pesticides is intended to represent conser vative estimates, and to avoid underestimations of the actual expos ure. The standard scenario consists of application to a 10-hectare field bordering a 1- hectare, 2-meter deep (20,000 m 3 

### ) 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 t op of watersheds includ ing 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 bodi es that have larger ratios of pesticidetreated drainage area to wate r 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 st orage capacity and thus may overflow and carry pesticide in the discharge, whereas the EXAM S pond has no discharge. As watershed size increases beyond 10-hectares, it becomes increasi ngly 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 uni que aquatic habitats th at are not accurately captured by this modeling scenario and modelin g results may, therefore, under- or overestimate exposure, depending on a number of va riables. For example, some organisms may
inhabit water bodies of different size and depth and/or are located adjacent to larger or smaller drainage areas than the EXAM S pond. In addition, the Servi ces agree that the existing EXAMS pond represents the best currently available approach for estimating aquatic exposure to pesticid es (USFWS/NMFS 2004).

PRZM-EXAMS modeled EECs are intended to repr esent exposure of aquatic organisms in relatively small ponds and low-order streams. Th erefore it is likely that EECs generated from
the PRZM-EXAMS model will over- estimate potential concentra tions in larger receiving water bodies such as estuaries, embayments, and coastal marine areas because chemicals in runoff water (or spray drift, etc.) should be diluted by a much larger volume of water than

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### would be found in the ‘typical’ EXAMS pond. Howe ver, as chemical constituents in water draining from freshwater streams encounter brackish or other near-marine-associated conditions, there is potential for important chemical transformati ons to occur. Many chemical compounds can undergo changes in mobility, toxicit y, or persistence when changes in pH, Eh (redox potential), salinity, dissolved oxygen (DO) content, or temperature are encountered. For example, desorption and re-mobilization of some chemicals from sediments can occur with changes in salinity (e.g., Means 1995; Sw arzenski et al. 2003; Jordan et al. 2008), changes in pH (e.g., Wood and Baptista 1993; Pari kh et al. 2004; Fernandez et al. 2005), Eh changes (Wood and Baptista 1993; Velde and Church 1999), and other factors. Thus, although chemicals in discharging rivers may be diluted by large volumes of water within receiving estuaries and embayments, the hydroche mistry of the marine-influenced water may negate some of the attenuating impact of the gr eater water volume; for example, the effect of dilution may be confounded by changes in chem ical mobility (and/or bioavailability) in brackish water. In addition, freshwater contri butions from discharging streams and rivers do not instantaneously mix with more saline wa ter bodies. In these settings, water will commonly remain highly stratified, with fresh water lying atop denser, heavier saline water – meaning that exposure to concentrations found in discharging stream water may propagate some distance beyond the outflow point of the st ream (especially near the water surface). Therefore, it is not assumed that discharging wa ter will be rapidly diluted by the entire water volume within an estuary, embayment, or ot her coastal aquatic environment. PRZM-EXAMS
model results should be considered consistent with concentrations that might be found near the head of an estuary unless there is specifi c information – such as monitoring data – to
indicate otherwise. Conditions nearer to th e mouth of a bay or estuary, however, may be closer to a marine-type system, and thus mo re subject to the notable buffering, mixing, and diluting capacities of an open marine environmen t. Conversely, tidal effects (pressure waves) can propagate much further upstream than the ac tual estuarine water, so discharging river water may become temporarily partially impoun ded near the mouth (d ischarge point) of a channel, and resistant to mixing until tidal forces are reversed.

The Agency does not currently have suffici ent information rega rding the hydrology and hydrochemistry of estuarine aquatic habitats to develop alternate scenar ios for assessed listed species that inhabit these t ypes of ecosystems. The Agen cy acknowledges that there areunique brackish and estuarine habitats that may not be accurately captured by PRZMEXAMS modeling results, and may, therefore, un der- or over-estimate exposure, depending
on the aforementioned variables.

In general, the linked PRZM/EXAMS model produ ces 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 fact ors such as rainfall and plant transpiration of water, as well as how and when the pesticid e is applied. It has two major components: hydrology and chemical transport. Water moveme nt is simulated by the use of generalized soil parameters, including field capacity, wilti ng point, and saturation water content. The chemical transport component can simulate pe sticide application on the soil or on the plant foliage. Dissolved, adsorbed, and vapor-phase concentrations in the soil are estimated by

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### simultaneously considering the processes of pesticide uptake by plants, surface runoff, erosion, decay, volatilization, fo liar wash-off, advection, di spersion, and retardation.

Uncertainties associated with each of thes e 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 ch osen 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 emer gence date, and canopy cover can also affect estimated concentrations, adding to the uncertain ty 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 av ailable to evaluate th e effectiveness of a vegetative setback on runoff and loadings. The e ffectiveness of vegetative setbacks is highly dependent on the condition of the vegetative st rip. 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 load ings. Until such time as a quantitative method to estimate the effect of vegetative setback s on various conditions on pesticide loadings becomes available, the aquatic exposure predictions are likely to overestimate exposure where healthy vegetative setbacks exist and unde restimate exposure where poorly developed, channelized, or bare setbacks exist.

6.1.2.1 Potential Groundwater Contribut ions to Surface Water Chemical
Concentrations

Although the potential impact of dischargi ng groundwater on CRLF populations is not explicitly delineated, it should be noted that groundwater coul d provide a source of pesticide to surface water bodies – especially low-orde r streams, headwaters, and groundwater-fed pools. This is particularly likely if the chemi cal is persistent and mobile. Soluble chemicals that are primarily subject to photolytic degr adation will be very likely to persist in groundwater, and can be transportable over long distances. Similarly, many chemicals degrade slowly under anaerobic conditions (common in aquifers) and are thus more persistent in groundwater. Much of this groundwater 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 groundwat er discharge, which can constitute 100% of stream flow during baseflow (no runoff) conditions . Thus, it is important to keep in mind that pesticides in groundwater may have a major (detrimental) impact on surface water quality,
and on CRLF habitats.

SciGrow may be used to determine likely ‘h igh-end’ groundwater vul nerability, with the assumption (based upon persistence in sub- and anoxic conditions, and mobility) that much of the compound entering the groundwater will be tr ansported some distance and eventually

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### discharged into surface water. Although con centrations in a rece iving water body resulting from groundwater discharge cannot be explicit ly quantified, it should be assumed that significant attenuation and retardation of the chemi cal will have occurred prior to discharge. Nevertheless, groundwater could still be a signi ficant consistent source of chronic background concentrations in surface water, and may also add to surface runoff during storm events (as a result of enhanced groundwater discharge typi cally characterized by th e ‘tailing limb’ of a storm hydrograph).

6.1.3 Multiple Growing Seasons per Year

Most endosulfan product labels specify applicat ion rates on a per crop cycle basis (not on a per year basis). Information from BEAD indicates that several crops can be grown more than one time/year in California, as indicated in Section 3 . Since standard PRZM scenarios only consist of one crop per year, ap plications to only one crop pe r year were modeled. The crops that may be grown multiple times in a calendar y ear that can be treated by endosulfan include Broccoli & Lettuce (two crops); Cabbage, Chines e cabbage, Cauliflower, Collards, Mustard Green & Sweet Corn (three crops ); and Kale (four crops). If endosulfan is applied for multiple cropping cycles within a year, EECs pr esented in this assessment may underpredict exposures. For all other labeled uses, it was assumed that a maximum seasonal application specified on the label was equivalent to a maximum annual application.

6.1.4 Usage Uncertainties

County-level usage data were obtained from Ca lifornia’s Department of Pesticide Regulation Pesticide Use Reporting (CDPR PU R) database. Thirteen ye ars of data (1994– 2006) were included in this analysis although error identification was not available for the older data from

1994 t0 1998. S 

### tatistical methodology for identifying outli ers, in terms of area treated and pounds applied, was provided by CDPR for late r years only (1999 to 2006). All data was included in order to analyze hi storical usage of endosulfan and no data was used as input parameter for modeling. CDPR PUR documentati on indicates that erro rs in the data may include the following: a misplaced decimal; in correct 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 can celled. The CPDR PUR data does not include home owner applied pesticides; therefore, reside ntial uses are not likel y to be reported. As with all pesticide usage data, th ere may be instances of misuse and misreporting. The Agency made use of the most current, verifiable informa tion; in cases where ther e were discrepancies,
the most conservative information was used.

6.1.5 Terrestrial Exposure Modeling of Endosulfan

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 possi ble that much of these data refl ect residues averaged over entire above ground plants in the case of grass and forage sampling.

217

### It was assumed that ingestion of food items in the field occurs at rates commensurate with those in the laboratory. A lthough the screening assessment process adjusts dry-weight
estimates of food intake to reflect the increa sed mass in fresh-weight wildlife food intake estimates, it does not allow for gross energy di fferences. Direct comparison of a laboratory dietary concentration- based effects threshold to a fresh-weight pest icide 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 diet s suggest that current screening assessment methods do not account fo r a potentially important aspect of food requirements. Depending upon species and dietar y 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 la boratory chow is formulated to maximize assimilative efficiency ( e.g. , a value of 85%), a potenti al 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 part icular terrestrial species were not considered, and it was assumed that species occupy, exclus ively and permanently, the modeled treatment area. Spray drift model predicti ons suggest that this assumption leads to an overestimation of exposure to species that do not occupy the treated field exclusively and permanently.

Exposure assessment for the SJKF did not include small mammal, avian, and reptilian dietary items. Diet items of SJKF include small animals ( e.g. blacktailed hares, desert cottontails, mice, kangaroo rats, squirrels), birds, lizards, in sects and grass. Although grass and insects are included in the dietary assessment of the fox, the current assessmen t is not inclusive of direct effects to the fox through all of its diet items. Exclusion of vertebrate dietary items is a limitation of the T-Rex model, but is not expected to affect the risk characterization outcome for the SJKF. For acute dose-based RQs, a ll modeled scenarios (N =20) resulted in an exceedance of the Agency’s acute listed species LOC (RQ> 0.1) for mammals and it was determined that there is a potential for direct adverse effects on SJKF individuals from foliar spray applications of endosul fan in CA. Inclusion of mamma lian and avian dietary items would increase the potential risk to SJKF. The current assessment, while conservative, represents the potential risk of SJKF exposure to endosulfan as highly probable for foliar spray applications.

The potential for endosulfan biomagnification in terrestrial food webs (i.e., increasing concentration with increasing trophic level) was not evaluated due to limitations in current risk assessment tools. However, a number of recent studies have been conducted for evaluating and predicting the bioa ccumulation of organic chemical s in food webs that involve terrestrial (air-respiri ng) organisms (e.g., Armitage and G obas, 2007; Kelly et al., 2007; Czub and McLachlan, 2004; Kelly and Gobas, 2003; Sharp and Mackay, 2000; McLachlan, 1996).

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### A key component from these studies has been th e relationship between observed or predicted bioaccumulation of poorly metabolized chemicals in terrestrial animals and the octanol-air partition coefficient (K OA 

### ). For terrestrial organisms, the relationship between the K OA 

### and bioaccumulation is somewhat analogous to the us e of the octanol-water partition coefficient (K OW 

### ) for predicting the bioaccumulation of noni onic organic chemicals by aquatic (waterrespiring) organisms. Based on model simula tions and supporting obser vations of chemical accumulation in Arctic terrestrial, purely aqua tic and marine mammalian food webs, Kelly et al. (2007) indicate that slowly-met abolized organic chemicals with relatively low to moderate

K OW 

### values (i.e., log K OW 

### between 2-5) and high K OA 

### values (i.e., log K OA 

### > 6) have the potential to biomagnify in te rrestrial and marine mammal food webs but not purely aquatic food webs. In their model, the conceptual basis for biomagnification of this group of compounds by terrestrial organisms relates larg ely to the greater ability of terrestrial organisms to assimilate food from their diet and their slower ability to eliminate these chemicals through respirator y processes relative to aquatic organisms.

Based on a log K OW 

### of 3.7 and log K OA 

### of 7.9 for β -endosulfan, Kelly et al. (2007) calculate that biomagnification factors (BMFs) range from 2.5 to 28 for various herbivorous and carnivorous terrestrial organisms, but are all less than 1 for aquatic organisms. Importantly,
these calculated BMF values assume that the chem ical is not metabolized in tissues of biota. Model predictions were evaluated against measur ed concentrations in tissues of organisms occupying terrestrial, piscivorous , and marine arctic food we bs (e.g., lichen, caribou, wolf food chain; macroalgae, zooplankton, bivalve, fish, whale/seal, polar bear food web) for a variety of chlorinated biphenyls, chlorinated benzenes, hexachlorocyclohexanes, cyclodienes (including endosulfan), and DDT-related compo unds. Agreement between the mean modelpredicted and observed concentrations in bi ota (lipid normalized) was generally good (i.e., many fell within a factor of three and all fell w ithin a factor of 10 of observed data). Limited
data were available for endosulfa n to directly verify model predictions and thus, the potential for biomagnifications in terrestrial food webs is largely based on i ndirect evidence (e.g., model predictions).

Regarding the bioaccumulation assessment in aquatic ecosystems (e.g., using the KABAM
model as described in Section 5 ), a significant sources of un certainty pertains to the variability associated with measured values of Kow for endosulfan isomers (alpha, beta). The reported log Kow values for the ά isomer range from 3.55 to 4.74 (McConnell et al., 1998 and MRID 41421501, respectively) and those for the β isomer range from 3.62 to 4.79 from the same sources. For parameterizing the KABAM mode l, the higher value of Kow was selected

6.1.6 Spray Drift Modeling

Although there may be multiple endosu lfan 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 endosulfan from multiple applications, each app lication of endosulfan would have to occur under identical atmospheric conditions ( e.g. , same wind speed and – for plants – same wind direction) and (if it is an anim al) the animal being exposed woul d have to be present directly
downwind at the same distance af ter each application. Although there may be sites where the

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### dominant wind direction is fair ly consistent (at least during the relatively quiescent conditions that are most favorable for aerial spray appli cations), it is neverthe less 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 avai lable meteorological da ta) wind direction is temporally very changeable, even within the same day. Additionally, other factors, including variations in topography, cover, and meteorol ogical conditions over the transport distance are not accounted for by the AgDRIFT/AGDISP model ( i.e ., it models spray drift from aerial and ground applications in a flat area with little to no ground cover and a steady, constant wind speed and direction). Therefore, in most cases, the drift estimates from AgDRIFT/AGDISP may overestimate exposure even from single applic ations, especially as the distance increases from the site of application, since the mode l does not account for pot ential obstructions ( e.g ., large hills, berms, buildings, trees, etc .). Furthermore, conservati ve assumptions are often made regarding the droplet size distributions be ing modeled (‘ASAE Very Fine to Fine’ for orchard uses and ‘ASAE Very Fine’ for ag ricultural uses), the application method ( e .g., aerial), release heights and wind speeds. Alterati ons in any of these inputs would change the area of potential effect.

6.2 Effects Assessment Uncertainties

6.2.1 Age Class and Sensitivit y of Effects Thresholds

It is generally recognized that test orga nism age may have a significant impact on the observed sensitivity to a toxicant. The acute toxi city 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 overe stimate toxicity at older age classes for pesticide active ingredients that act directly without metabo lic transformation because younger age classes may not have the enzymatic systems associated w ith detoxifying xenobiotics. In so far as the available toxicity data may provide ranges of se nsitivity information with respect to age class,
this assessment uses the most sensitive life-st age information as measures of effect for surrogate aquatic animals, and is th erefore, considered as protective.

6.2.2 Use of Surrogate Species Effects Data

Guideline toxicity tests and open literature data on endosulfan considered suitable for quantitative use are not availabl e for frogs or any other aquati c-phase amphibian; therefore, freshwater fish are used as surrogate species for aquatic-phase amphibians. Although no data are available for endosulfan , the available open literature information on endosulfan toxicity to aquatic-phase amphibians shows that acute and chronic ecotoxicity endpoints for aquaticphase amphibians range from approximately 2 to > 4000 times less sensitive than the most sensitive freshwater fish (LC50 0.01 ug a.i./L) us ed in this assessment. Therefore, endpoints
based on freshwater fish ecotoxi city data are assumed to be protective of potential direct effects to aquatic-phase amphi bians including the CRLF, and extrapolation of the risk conclusions from the most sensitive tested species to the aquatic-phase CRLF and CTS and

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### may overestimate the potential risks to those sp ecies. For reptiles (SFGS) and terrestrial phase amphibians (CRLF, CTS), no data on thei r sensitivity to endosulfan was identified. Therefore, the uncertainty in using avian effects data as a surrogate for reptiles and terrestrialphase amphibians could not be ch aracterized. Efforts are made to select the organisms most likely to be affected by the type of compound a nd 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 ma de 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 s ublethal responses to the pesticid e, as determined by the testing of species response to chronic exposure conditions and subseque nt chronic risk assessment.
Consideration of additional sublethal data in th e effects determination t is exercised on a caseby-case basis and only after caref ul consideration of the natu re of the sublethal effect measured and the extent and quality of availa ble data to support es tablishing 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.

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 part icular terrestrial species were not considered, and it was assumed that species occupy, exclus ively and permanently, the modeled treatment area. Spray drift model predicti ons suggest that this assumption leads to an overestimation of exposure to species that do not occupy the treated field exclusively and permanently.

6.2.5 Endocrine Disruption

EPA is required under the FFDCA, as amended by FQPA, to develop a screening program to determine whether certain substances (includi ng all pesticide active a nd other ingredients) “may have an effect in humans that is similar to an effect produced by a naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” Following the recommendations of its Endocrine Disruptor Screening and Testing Advisory Committee (EDSTAC), EPA determined that there were scie ntific bases for including, as part of the program, androgen and thyroid hormone systems, in addition to the estrogen hormone system. EPA also adopted EDSTAC’s recommendation that the Program include evaluations of potential effects in wildlife. When the appropr iate screening and/or testing protocols being considered under the Agency’s Endocrine Disr upter Screening Program (EDSP) have been developed and vetted, endosulfan ma y be subjected to additional screening and/or testing to
better characterize effects rela ted to endocrine disruption.

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# 7 Summary and Conclusions

In fulfilling its obligations under Section 7(a)(2) of the Endangered Species Act, the information presented in this endangered specie s risk assessment represents the best data currently available to assess the potential risks of endosul fan to the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and the designat ed critical habitat for CRLF, CTS, BCB and

VELB.

Based on the best available information, the Agency makes a Likely to Adversely Affect determination for the CRLF, CTS, SFGS, SMHM , SJKF, BCB, and VELB from the use of endosulfan. Additionally, the Agency has determin ed that there is the potential for effects to the designated critical habitat for the CRL F, CTS, BCB and VELB from the use of the
chemical. Given the LAA determination fo r the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and potential effects to designate d critical habitat for CRLF, CTS, BCB and VELB, a description of the baseline status and cumulative effects for the CRLF is provided
in Attachment 2 and the baseline status and cumulative effects for the CRLF, CTS, SFGS, BCB, VELB, SMHM, and SJKF in Attachment 4

.

A summary of the risk conclusions and effect s determinations for the CRLF, CTS, SFGS, SMHM, SJKF, BCB, and VELB and their critical habitat, given the uncertainties discussed in Section 6, is presented inError! Re ference source not found. and Table 7.2

.

Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects
Determination 1 Basis for Determination

POTENTIAL FOR DIRECT EFFECTS
California redlegged frog ( Rana aurora

draytonii )

(CRLF) LAA 1 Aquatic-phase CRLF (Eggs, Larvae, and Adults) : Freshwater Fish RQ - Acute RQs for freshwater fish (used as a surrogate for aquatic-phase CRLFs) exceed the listed species acute risk LOC fo r all 20 modeled crop scenarios. - Chronic RQs for freshwater fish (used as a surrogate for aquatic-phase CRLFs)
exceed the chronic risk LOC for a ll 20 modeled crop scenarios.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for freshwater fish (surrogate for aquatic-phase CRLFs) is as high as ~1 in 1.

Ecological Incident Reports - 67 of the 83 endosulfan-associated ecological incidents reported to the Agency
involve fish and 53 of these ar e classified as ‘probable’ or ‘highly probable;’ 18 of the 20 incident reports associated with ‘registered uses’ involved mortality to fish.

Species Sensitivity Differences - Model-based EECs exceed the LOC for approximately 80 to 97% of the tested freshwater fish species

Surface Water Monitoring Data - The highest reported values of total endosulfan in California equal or exceed the
acute LOC for freshwater fish.



### 222Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
Bioaccumulation in Aquatic Prey - Based on consumption of aquatic prey that is predicted to bioaccumulate endosulfan, acute dose-based RQs exceed the acute listed LOC in all 20 crop exposure scenarios modeled for small, medium and large CRLF.

Temporal and Spatial Overlap - Based on current endosulfan use data and potential endosulfan use on agricultural crops/orchards/vineyard areas, there appears to be a potential for both temporal and spatial overlap between aquatic-phase CRLF distribution and endosulfan agricultural use ( Appendix E ). Terrestrial-phase CRLF (Juveniles and Adults) : Direct Deposition on Forage Items: Avian RQ - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; and acute dietary-based species/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (sur rogate for terrestrial - phase CRLFs) and herpetofauna based on direct deposition onto food items is as high
as ~1 in 1.

Temporal and Spatial Overlap - Based on current endosulfan use data and potential endosulfan use on agricultural crops/orchards/vineyard areas, there appears to be a potential for both temporal and spatial overlap between terrestrial -p hase CRLF distribution and endosulfan agricultural use ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS CRLF Aquatic Prey Items, Aquatic Habita t, Cover and/or Primary Productivity Freshwater fish and aquatic-phase amphibians : - Acute and chronic RQs exceed the liste d species acute and chronic LOCs; high likelihood of individual mortality, EECs exceed the LOC for 80 % or more of the tested fish species and a large number of aquatic incidents involving fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

. Freshwater Invertebrates : -Acute and chronic RQs for freshwater in vertebrates exceed the listed species acute
and chronic risk LOC for all 20 cr op exposure scenarios modeled. -The chance of individual effects ( i.e ., mortality) for freshwat er invertebrates is as high as ~1 in 1. - Model-based EECs exceed the LOC for approximately 45% to 60% of the tested freshwater invertebrate species - The highest reported values of total endosulfan in California equal or exceed the
listed acute LOC and chronic LOC for freshwater invertebrates.



### 223Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
CRLF Terrestrial Prey Items, Riparian Habitat Terrestrial-phase Amphibians : - Exceedence of acute and chronic LOCs for terrestrial-phase amphibians as described above for CRLF (see “ Potential Direct Effects; Terrestrial Phase CRLF [juveniles and adults]) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively. -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.
- When indirect effects are considered via ex posure of terrestrial insects to spray drift, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source ( Appendix E ).

Small Mammals: Direct Deposition on Forage Items - Acute and chronic dose-based RQs for small mammals foraging on food items receiving direct deposition of applied e ndosulfan exceed the acute listed LOC for mammals in all 20 crop scenarios modeled - Chronic diet-based RQs for small mammals foraging on food ite ms receiving direct deposition of applied endosulfan exceed the chronic LOC for mammals in 13 of the 20 crop scenarios modeled - The chance of individual effects ( i.e ., mortality) for small mammals is as high as ~1
in 1.

Small Mammals: Bioaccumulation in Terrestrial Prey - RQs exceed of acute listed and chronic LOCs in all 20 exposure scenarios modeled based on small mammals eating earthworms that are predicted to bioaccumulate
endosulfan from soil.
POTENTIAL FOR DIRECT EFFECTS California tiger
salamander

( Ambystoma californiense LAA 1

Direct Deposition on Forage Items: Avian RQ (Terrestrial-Phase CTS) - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; acute dietary-based sp ecies/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (s urrogate for reptiles and terrestrial phase amphibians) and herpetofauna based on direct deposition onto food items is as high as ~1 in 1.

Bioaccumulation in Aquatic Prey



### 224Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
- Based on consumption of aquatic prey that is predicted to bioaccumulate endosulfan, acute dose-based RQs exceed the acute listed LOC in all 20 crop exposure scenarios modeled for small CRL F (used as surrogate for CTS exposure potential).

Bioaccumulation in Terrestrial Prey - Based on consumption of terrestrial prey (earthworm) that is predicted to bioaccumulate endosulfan, acute dose-bas ed RQs and chronic diet-based RQs for small birds (surrogate for terrestrial-phas e amphibians) exceed the acute listed and chronic LOCs in all 20 crop exposure scenarios modeled.

Freshwater Fish (Aquatic-phase CTS) : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of CTS was
identified.

- A large amount of spatial overlap between CTS occurrence and current (and potential future use) of endosulfan was identified ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS

Freshwater Fish : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

Freshwater Invertebrates: - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, and exceedence of LOCs for 45-60% of freshwater invertebrate species tested, as described above for CRLF (see “ Potential Indirect Effects; CRLF Aquatic Prey Items, Aquatic Habitat, Cover and/or Primary Productivity) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)
POTENTIAL FOR DIRECT EFFECTS San Francisco garter snake ( Thamnophis
sirtalis

tetrataenia ) LAA 1
Direct Deposition on Forage Items: Avian RQ - Acute-dose based RQs for 20g birds (surrogate for terrestrial-phase amphibians) consuming large and small insects contaminated with endosulfan from direct deposition exceed LOC for all 20 crop scenarios modeled. - Chronic RQs for the small and large insect categories exceed th e Agency LOC of 1 for 20 and 3 crop exposure scenarios, respectively.



### 225Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

Direct Deposition on Forage Items: Refined Herpetofauna Modeling - Using refined modeling, acute listed LOC was exceeded in 39% or more of the acute dose-based; and acute dietary-based species/diet combinations modeled. The
chronic LOC was exceeded in 46% of th e chronic dietary-based species/diet
combinations modeled.

Likelihood of Individual Mortality The chance of individual effects ( i.e ., mortality) for birds (s urrogate for reptiles and terrestrial phase amphibians) and herpetofauna based on direct deposition onto food items is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of SFGS was
identified. - No spatial overlap identified at the County level based on current endosulfan use reported for California. If cultivated crop /orchard/vineyard uses are considered areas of potentia l endosulfan use in the future, then a substantial amount of spatial overlap
can be observed relative to the tota l area of SFGS occurrence sections ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS Prey Items, Habitat, Cover And/Or Primary Productivity
Freshwater Fish : - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, EECs exceed the LOC for 80% or more of the tested fish species and a large number of aquatic incidents involve fish, as described above for CRLF (see “ Potential Direct Effects; Aquatic Phase CRLF [eggs, larvae, adults]) ”

Freshwater Invertebrates: - Acute and chronic RQs exceed the listed sp ecies acute and chronic LOCs, there is a high likelihood of individual mortality, and exceedence of LOCs for 45-60% of freshwater invertebrate species tested, as described above for CRLF (see “ Potential Indirect Effects; CRLF Aquatic Prey Items, Aquatic Habitat, Cover and/or Primary Productivity) ”

Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Terrestrial Vertebrates
- Acute and chronic LOC exceedence for bird s (surrogate for reptiles and terrestrialphase amphibians) and herpetofauna for direct deposition on food items, a high
likelihood of individual mortality, and RQ exceedence of acute listed LOC and chronic LOC based on consumption of terrestrial and aquatic prey by birds and mammals as described above for the CRLF (see “ Potential Direct Effects; Terrestrial Phase CRLF [juveniles and adults] and “Potential for Indirect Effects: CRLF Terrestrial Prey Items, Riparian Habitat) ”
POTENTIAL FOR DIRECT EFFECTS Salt marsh
harvest mouse LAA 1
Direct Deposition on Forage Items: Mammalian RQ



### 226Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
- Acute and chronic dose-based RQs for small mammals foraging on food items receiving direct deposition of applied e ndosulfan exceed the acute listed LOC for mammals in all 20 crop scenarios modeled - Chronic diet-based RQs for small mammals foraging on food ite ms receiving direct deposition of applied endosulfan exceed the chronic LOC for mammals in 13 of the 20 crop scenarios modeled

Likelihood of Individual Mortality - The chance of individual effects ( i.e ., mortality) for small mammals resulting from direct deposition onto forage items is as high as ~1 in 1.

Bioaccumulation in Terrestrial Prey - RQs exceed of acute listed and chronic LOCs in all 20 exposure scenarios modeled based on small mammals eating earthworms that are predicted to bioaccumulate
endosulfan from soil.

Temporal and Spatial - Temporal overlap between endosulfan app lication and all life stages of the SMHM
was identified. - A small amount of spatial overlap identif ied at the County level based on current endosulfan use reported for California and based on areas of potentia l endosulfan use in the future (i.e., cultivated crop, orchard and vineyard use areas). - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase SMHM exposure, particularly in ar eas of potential endosulfan use west of SMHM occurrence sections in Solano County ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS ( Reithrodonto

mys raviventris )

(SMHM)

Prey items, habitat, cover and/or primary productivity
Terrestrial invertebrates :

-- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Birds and Mammals (rearing sites) : - Acute and chronic RQ for birds and mamm als (whose rearing sites are potentially used by SMHM) exceed listed acute and chroni c LOCs as a result of direct deposition onto forage items and bioaccumulation in terrestrial prey as described above for the CRLF ( Potential for Direct Effects: Terrestrial-phase CRLF [Juveniles and Adults]) and for the SMHM (see “ Potential for Direct Effects” )
POTENTIAL FOR DIRECT EFFECTS San Joaquin
kit fox ( Vulpes

macrotis

mutica ) LAA 1

Direct Deposition on Forage Items: Mammalian RQ - Acute and chronic dose-based RQs exceed the Agency acute listed and chronic LOC in all modeled scenarios (N=20) for large mammals. Chronic dietary-based RQs
exceed the chronic LOC in all 20 modeled s cenarios for large mammals that feed on short grass, tall grass, and broadleaf plan ts/small insects (chronic dietary-based RQs for 13/20 scenarios exceed the LOC for large mammals consuming fruits/pods/seeds/large insects).

Temporal and Spatial Overlap - Temporal overlap between endosulfan app lication and all life stages of SJKF was



### 227Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1

identified.

- A moderate amount of spatial overlap between SJKF occurrence and current (and potential future use) of endosulfan was identified ( Appendix E ).

POTENTIAL FOR INDIRECT EFFECTS
Terrestrial Invertebrates :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled, there is a high likelihood of individual mortality, and EECs exceed LD50 values for vast majority of tested species, as described above for CRLF (see “ Potential for Indirect Effe cts: CRLF Terrestrial Prey Items, Riparian Habitat)

Small Birds and Mammals : - Acute and chronic RQ for birds and mamm als serving as prey to the SJKF exceed
listed acute and chronic LOCs as a result of direct deposition onto forage items and bioaccumulation in terrestrial prey as described above for the CRLF ( Potential for Direct Effects: Terrestrial-phase CRLF [Juveniles and Adults]) and for the SMHM (see “ Potential for Direct Effects” )
POTENTIAL FOR DIRECT EFFECTS Terrestrial Invertebrate RQs :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan ap plication and all life stages of BCB was
identified. - No spatial overlap identified at the County level based on current endosulfan use reported for California. If cultivated crop /orchard/vineyard uses are considered areas of potentia l endosulfan use in the future, then a substantial amount of spatial overlap
can be observed relative to the total area of BCB occurrence sections. - When exposure of terrestrial insects via spray drift is considered, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source. - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase BCB exposure, particularly in areas of potential endosulfan use west of BCB occurrence sections in Santa Clara County ( Appendix E ).
POTENTIAL FOR INDIRECT EFFECTS Bay checkerspot

butterfly ( Euphydryas
editha bayensis )

(BCB) LAA 1

-Although effects to terrestria l plants cannot be quantified due to the lack of data, aquatic non-vascular plants are not particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. - No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plant have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular



### 228Table 7.1 Effects Determinati on Summary for Effects of Endosulfan on the CRLF, CTS, SFGS, SMHM, SJKF, BCB, AND VELB Species Effects Basis for Determination
Determination 1
plants are insensitive relative to aquatic animals. - No ecological incidents have been reported to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regul arly directly applied on or near a very wide variety of agricultural plants.

POTENTIAL FOR DIRECT EFFECTS Terrestrial Invertebrate RQs :

- Acute RQs exceed the Agency’s interim LOC for listed terrestrial invertebrates in all 20 crop exposure scenarios modeled. - EECs exceed for large and small insects exceed the LD50 values for 80% and 99%
of the tested terrestrial inve rtebrate species, respectively.

Likelihood of Individual Mortality -The chance of individual effects ( i.e ., mortality) for terrestrial invertebrates resulting from direct deposition in application sites is as high as ~1 in 1.

Temporal and Spatial Overlap - Temporal overlap between endosulfan app lication and all life stages of VELB was
identified. - A small amount of spatial overlap identif ied at the County level based on current endosulfan use reported for California. If cultivated crop/orchard/vineyard uses are considered areas of potentia l endosulfan use in the future, then a moderate amount of spatial overlap can be observed relative to the total area of VELB occurrence sections ( Appendix E ). - When exposure of terrestrial insects via spray drift is considered, spatial overlap between potential endosulfan use on agricultural crops, orchards, and vineyard areas can extend up to 2 miles from the source - The potential for endosulfan to be transpor ted long distances in the atmosphere may increase VELB exposure, particularly in ar eas of potential endosulfan use west of
VELB occurrence sections.
POTENTIAL FOR INDIRECT EFFECTS Valley elderberry longhorn
beetle ( Desmocerus californicus dimorphus ) LAA 1

-Although effects to terrestria l plants cannot be quantified due to the lack of data, aquatic non-vascular plants are not particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. - No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plant have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic animals. - No ecological incidents have been reported to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regul arly directly applied on or near a very wide variety of agricultural plants.



### Table 7.2 Effects Determination Summary for the Critical Habitat Impact Analysis Designated
Critical Habitat
for: Effects
Determination 1 Basis for Determination



### 229CRLF May Affect -There is a potential for direct effects to the aquatic-phase CRLF and indirect effects via reduction of aquatic-phase prey items (aquatic invertebrates, fish, and aquatic-phase amphibians) as described in Table 7.1
above. - There is a potential for direct eff ects to the terrestrial-phase CRLF and
indirect effects via reduction of te rrestrial-phase prey items (mammals, amphibians, and terrestrial invertebrates) as described in Table 7.1 above.

CTS May Affect There is a potential for direct effect s to the CTF and indirect effects via reduction of aquatic-phase prey items (aquatic invertebrates and fish) as
described in Table 7.1 above. - There is a potential for direct effect s to the CTF and indirect effects via reduction of terrestrial-phase prey ite ms (terrestrial invertebrates) as
described in Table 7.1 above.

BCB NE 1 -Although effects to terrestrial plants ca nnot be quantified due to the lack of data, aquatic non-vascular plants are no t particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. -No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plan t have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic
animals. - No ecological incidents have been repo rted to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regularly directly applied on or near a very wide variety of agricultural plants.

VELB NE 1 -Although effects to terrestrial plants ca nnot be quantified due to the lack of data, aquatic non-vascular plants are no t particularly sensitive to endosulfan
- Endosulfan has a neural toxic mode of action. -No studies demonstrating significant adverse effects of endosulfan to any vascular aquatic or terrestrial plan t have been identified in the open literature. The one toxicity study found to be acceptable for quantitative use suggests that aquatic nonvascular plants are insensitive relative to aquatic
animals. - No ecological incidents have been repo rted to the Agency that involve any plants and this was classified with a certainty index of “probable” or higher linking endosulfan as a cause, despite that it is regularly directly applied on or near a very wide variety of agricultural plants.

1 No effect (NE)



### Based on the conclusions of this assessment, a formal consultation with the U. S. Fish and
Wildlife Service under Section 7 of the Enda ngered Species Act should be initiated. When evaluating the significance of this risk assessment’s direct/indire ct and adverse habitat modification effects determinations, it is im portant to note that pesticide exposures and predicted risks to the listed 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 distan ce), pesticide exposure and associated risks to the species and its resources are expected to d ecrease with increasing di stance away from the treated field or site of application. Eval uation of the implication of this non-uniform distribution of risk to the sp ecies would require information and assessment techniques that are not currently available.

When evaluating the significance of this risk assessment’s direct/indire ct and adverse habitat modification effects determinations, it is im portant to note that pesticide exposures and

230

### predicted risks to the species a nd its resources (i.e., food and hab itat) are not expected to be uniform across the action area. In fact, gi ven the assumptions of drift and downstream transport (i.e., attenuation with distance), pe sticide exposure and associated risks to the species and its resources are expected to d ecrease with increasing di stance away from the treated field or site of application. Eval uation of the implication of this non-uniform distribution of risk to the sp ecies would require information and assessment techniques that are not currently available. Examples of su ch information and methodology required for this type of analysis would include the following:

• Enhanced information on the density a nd distribution of CRLF, CTS, SFGS, BCB, VELB, SMHM, and SJKF life stag es within the action area and/or applicable designated critical habitat. This information would allow for quantitative extrapolation of the pres ent risk assessment’s predictions of individual effects to the proporti on 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 impa irment to individuals of the assessed species.

• Quantitative information on prey base requirements for the assessed species. While existing information provides a prel iminary picture of the types of food sources utilized by the assessed spec ies, it does not establish minimal requirements to sustain healthy individua ls at varying life stages. Such
information could be used to establis h 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 like lihood of adverse eff ects 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 reprod uctive impairment immediately following exposure to the pesticide. The degree to which repeated exposure events and the inherent demographic characteristic s of the prey population play into the extent to which prey resources may rec over 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 indi vidual species and potential modification
to critical habitat.

231

# 8 References

Registrant Submitted Studies MRID 000369-35 Atkins. E.L., E.A. Greywood, a nd R.L. MacDonald. 1975. Toxicity of pesticides and other agricultu ral chemicals to honey bees. Laboratory studies. Univ. of Calif., Div. Agric. Sci. Leaflet 2287. 38 pp.

MRID 45421402 Gries, T.; van der Kolk, J. (2000) (Carbon 14) Endosulfan sulfate (metabolite of (Carbon 14-Endosulfan) Acute Toxicity Test with Carp (Cyprinus carpio ) under Static Conditions: Lab Project Number: 1049.014.170: C010869. Unpublished study prepared by Springborn Laboratory (Europe) AG. 52 p.

MRID 45421403 Gries, T.; van der Kolk, J. (2000) (Carbon 14) Endosulfan sulfate (metabolite of (Carbon 14-endosulfan) Ac ute Immobilisation Test with Daphnids ( Daphnia magna ) under Static Conditions: Lab Project Number: 1049.014.110: C012413. Unpublished study prepared by Spri ngborn Laboratory (Europe) AG. 64 p.

MRID 22923 Hill, E.F.; Heath, R.G.; Spa nn, J.W.; et al. (1975) Lethal Dietary
Toxicities of Environmental Pollutants to Birds: Special Scientific Report--Wildlife No. 191. (U.S. Dept. of the Interior, Fish and Wildlife Service, Patuxent Wildlife Research Center; unpublished report).

MRID 5005824 Schimmel, S.C.; Patrick, J.M ., Jr.; Wilson, A.J., Jr. (1977) Acute toxicity to and bioconcentr ation of endosulfan by estuarine animals. Pages 241-252, in Aquatic Toxicology and Hazard Evaluation. Ed ited by F.L. Mayer and J.L. Hamelink. Philadelphia, Pa.: American Soci ety for Testing and Materials.

MRID 38307 Reno, F.E. (1975) Final Report: Acute Oral Toxicity Study in Rats: Project No. 915-108. (Unpublished study received Jul 28, 1980 under 2749-487; prepared by Hazleton Laboratories America, Inc., submitted by Aceto Chemical Co., Inc., Flushing, N.Y.; CDL: 243082-A)

MRID 1328 Earnest, R. (1970) Annual progr ess report: 1970 effects of pesticides on aquatic animals in the estuarine and mari ne environment. (Unpublished study receivedNov 26, 1976 under 241-132; prepared by U.S. Fish and Wildlife Service, fishPesticide Research Labora tory, submitted by American Cyanamid Co., Princeton, N.J.; CDL: 129448-W).

MRID 1999 Atkins, E.L.,Jr; Anderson, J.D. (1967). Toxicity of pe sticides and other agricultural chemical s to honey bees: laboratory studi es. (Unpublished study received Jan. 30, 1969 under 9G0802; prepared by Univ. of California-Riverside, Dept. of Entomology, submitted by Hercules, Inc., Agricultural Chemicals, Wilmington, Del.; CDI: 093111-D).

232

### MRID 38806 Buccafusco, R.J. (1976) Acute Toxicity of Endosulfan Technico to Bluegill ( Lepomis macrochirus ). (Unpublished study received Jul 28, 1980 under 2749-487; prepared by EG&G, Bionomics, sub- mitted by Aceto Chemical Co., Inc., Flushing, N.Y.; CDL: 243084-A)

MRID 136998 Roberts, N.; Phillips, C. (1983) The Acute Oral Toxicity (LD50) of Endosulfan--Technical (Code: HOE 002671 OI ZD97 0003) to the Mallard Duck: HST 226/83493. (Unpublished study received Dec 27, 1983 under 8340-13; prepared by Huntingdon Research Centre, Eng., submitted by American Hoeschst Corp., Somerville, NJ; CDL: 252043-F).

MRID 137189 Roberts, N.; Phillips, C. (1983) The Acute Oral Toxicity (LD50) of Endosulfan Technical (Code: Hoe 002671 OI ZD97 0003) to the Bobwhite Quail: HST 224/83566; A27035. (Unpublished study received Jan 16, 1984 under 11678-5; prepared by Huntingdon Research Centre, Eng., submitted by Makhteshim Beer Sheva Chemical Works, Ltd., New York, NY; CDL:252229-A).

MRID 146843 Roberts, N.; Phillips, C.; Dawe, I.; et al. (1985) The Effects of Dietary
Inclusion of Endosulfan--Technical on Reproduction in the Mallard Duck. HRC Report No. HST 228b/841012. Unpublished study prepared by Huntington Research Centre plc. 211 p.

MRID 148264 Edwards, J.; Reid, Y.; Offer, J.; et al. (1984) Effect of Endosulfan-- Technical on Reproductive Function of Mu ltiple Generations of the Rat: Report No. HST 204/83768. Unpublished study prepared by H untingdon Research Centre plc. 422

p.

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