Assessment

305 Pages·2015·4.88 MB·English

by  Housenger, Justin

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND
POLLUTION PREVENTION

Preliminary Pollinator Assessment to Support the
Registration Review of Imidacloprid

January 4th, 2016
PC Code: 129099. IUPAC Name: N-{1-[(6-Chloro-3-pyridyl)methyl]-4,5-dihydroimidazol-2-yl}nitramide

Prepared by: United States Environmental Protection Agency
US EPA - Office of Pesticide Programs
Justin Housenger, M.S., Biologist Environmental Fate and Effects Division
Keith G. Sappington, M.S, Senior Science Advisor Environmental Risk Branch V
Mohammed A. Ruhman, Ph.D., Senior Agronomist 1200 Pennsylvania Ave.
Mail Code 7507P
California Department of Pesticide Regulation: Washington, D.C. 20460
Richard Bireley, Sr. Environmental Scientist (Specialist)
John Troiano, Ph.D., Research Scientist III
Denise Alder, Sr. Environmental Scientist (Specialist)

Approved by
Mah T. Shamim, Ph.D. Branch Chief
1
Contents
Contributors, Reviewers, and Acknowledgements ..................................................................................... 12
1. Executive Summary ............................................................................................................................. 13
1.1. Background and Scope ................................................................................................................ 13
1.2. Use Characterization ................................................................................................................... 13
1.3. Environmental Fate and Transport ............................................................................................. 13
1.4. Exposure Assessment .................................................................................................................. 14
1.5. Effects Assessment...................................................................................................................... 14
1.6. Pollen Route of Exposure ............................................................................................................ 16
1.7. Non-Apis Bee Characterization ................................................................................................... 16
1.8. Additional Lines of Evidence ....................................................................................................... 17
1.9. Risk Conclusions .......................................................................................................................... 17
2. Problem Formulation .......................................................................................................................... 24
2.1. Registration Review Background ................................................................................................ 24
2.2. Nature and Scope of Assessment ............................................................................................... 24
2.3. Pesticide Type, Class, and Mode of Action ................................................................................. 25
2.4. Overview of Imidacloprid Uses ................................................................................................... 26
2.5. Overview of Physicochemical, Fate, and Transport Properties .................................................. 26
2.6. Stressors of Toxicological Concern ............................................................................................. 26
2.7. Protection Goals and Assessment Endpoints ............................................................................. 27
2.8. Conceptual Models and Risk Hypotheses ................................................................................... 28
2.8.1. Foliar Spray................................................................................................................................ 28
2.8.2. Soil Application ......................................................................................................................... 30
2.8.3. Seed Treatment ......................................................................................................................... 31
2.9. Analysis Plan................................................................................................................................ 32
2.9.1. Risk Assessment Methodology ................................................................................................. 32
2.10. Measures of Exposure ............................................................................................................. 37
2.11. Measures of Effects ................................................................................................................. 37
3. Use Characterization ........................................................................................................................... 39
3.1. Agricultural Uses ......................................................................................................................... 39
3.1.1. Foliar Applications ..................................................................................................................... 40
3.1.2. Soil Applications ........................................................................................................................ 42
3.1.3. Seed Treatments ....................................................................................................................... 43
2
3.1.4. Multiple Application Types (e.g. combinations of seed, soil, and/or foliar) ............................. 45
4. Exposure Assessment .......................................................................................................................... 46
4.1. Physical/chemical and fate and transport properties ................................................................ 47
4.1.1. Physical/Chemical properties ................................................................................................... 48
4.1.2. Environmental Fate and Transport Properties ......................................................................... 48
4.2. Imidacloprid Plant Up-take ......................................................................................................... 55
4.2.1. Imidacloprid applied to soil including seed treatment ............................................................. 55
4.2.2. Imidacloprid applied to foliage and fruits ................................................................................. 56
4.2.3. Imidacloprid: soil versus foliage applied ................................................................................... 57
4.3. Plant Metabolism of Imidacloprid .............................................................................................. 58
4.3.1. Imidacloprid metabolism in various plants ......................................................................... 59
4.3.2. Imidacloprid metabolism profile in plants .......................................................................... 60
4.3.3. Imidacloprid metabolism profile in plants .......................................................................... 62
4.4. Potential for Exposure to Bees ................................................................................................... 63
4.5. Screening-level Exposure Estimation .......................................................................................... 68
4.6. Experimental Residue Studies ..................................................................................................... 71
4.6.1. Rationale for Residue-based EEC Selection for Refined Tier I ............................................ 71
4.6.2. Rationale for Comparing Residue Data With Tier II Endpoints ........................................... 73
4.6.3. Foliar Application Residue Studies – Registrant Submitted ................................................ 73
4.6.4. Soil Application Residue Studies – Registrant Submitted ................................................... 77
4.6.5. Soil Application Residue Studies – Open Literature ............................................................ 83
4.6.6. Seed Treatment Application Residue Studies – Registrant Submitted ............................... 86
4.6.7. Seed Treatment Application Residue Studies – Open Literature ....................................... 91
4.6.8. Combined Application Method Residue Studies ................................................................ 93
4.7. Carry-over of Imidacloprid Residues in Soil ................................................................................ 97
4.8. Observational Residue Monitoring Studies ................................................................................ 98
4.8.1. Agricultural crop studies ..................................................................................................... 99
4.8.2. Hive monitoring studies ...................................................................................................... 99
5. Effects Assessment............................................................................................................................ 101
5.1. Tier I .......................................................................................................................................... 101
5.1.1. Adult Acute Contact Toxicity ............................................................................................. 103
5.1.2. Adult Acute Oral Exposure ................................................................................................ 110
5.1.3. Adult Chronic Oral Toxicity (Apis and non-Apis) ............................................................... 115
3
5.1.4. Larval Acute Oral Toxicity.................................................................................................. 117
5.1.5. Larval Chronic Oral Toxicity............................................................................................... 118
5.1.6. Acute and Chronic Toxicity of the Degradation Products of Imidacloprid ....................... 120
5.2. Tier II ......................................................................................................................................... 123
5.2.1. Registrant-Submitted ........................................................................................................ 123
5.2.2. Open Literature Studies .................................................................................................... 127
5.3. Tier III ........................................................................................................................................ 154
5.3.1. Registrant Submitted ........................................................................................................ 154
5.3.2. Open Literature ................................................................................................................. 154
5.4. Reported Pollinator Incident Information ................................................................................ 160
6. Risk Characterization ........................................................................................................................ 168
6.1. Risk Estimation .......................................................................................................................... 168
6.1.1. Tier I - Screening-level RQs (On-field Contact – Foliar Uses Only) .................................... 174
6.1.2. Tier I - Screening-level RQs (On-field oral) ........................................................................ 175
6.1.3. Screening Level RQs (Off-Field) ......................................................................................... 177
6.1.4. Refined RQs (On-field Oral) ............................................................................................... 183
6.1.5. Refined RQs (Off-field Oral) .............................................................................................. 204
6.1.6. Uncertainties at the Tier I Level ........................................................................................ 205
6.2. Risk Description ......................................................................................................................... 206
6.2.1. Characterization of Tier I Risks and Tier II Analysis ........................................................... 207
6.2.2. Tier III analysis ................................................................................................................... 271
6.2.3. Examination of the pollen route of exposure ................................................................... 272
6.2.4. Risk Characterization of Non-Apis Bees ............................................................................ 277
6.2.5. Additional Lines of Evidence ............................................................................................. 283
6.2.6. Higher Tier and other General Uncertainties.................................................................... 284
7. Conclusions ....................................................................................................................................... 287
8. References ........................................................................................................................................ 293

Table of Tables
Table 1-1. Summary of the toxicity endpoints to be used in risk estimation for individual bees. ............ 15
Table 1-2. Summary of risk findings for honey bees (Apis mellifera) for the registered use patterns of
imidacloprid ................................................................................................................................................ 20
Table 2-1. Protection goals and examples of associated assessment and measurement (population and
individual) endpoints for bees. ................................................................................................................... 28
4
Table 3-1. Summary of labeled use information for foliar applications of imidacloprid ........................... 40
Table 3-2. Summary of labeled use information for soil applications of imidacloprid ............................... 42
Table 3-3. Summary of labeled use information for seed treatment applications of imidacloprid ........... 44
Table 4-1. Chemical profile of imidacloprid ................................................................................................ 48
Table 4-2. Fate and transport properties for imidacloprid ......................................................................... 48
Table 4-3. Imidacloprid root up-take/distribution and resultant concentrations in cotton, potatoes, corn
and eggplant (%= up-take in % of the applied radioactivity and numbers in brackets are resultant
concentrations in mg/kg) ............................................................................................................................ 55
Table 4-4. Imidacloprid up-take/distribution and resultant concentrations in various parts of the potato
plants and only in the fruits of apples and tomatoes (%= up-take in % of the applied radioactivity and
numbers in brackets are resultant concentrations in mg/kg). ................................................................... 57
Table 4-5. Observed estimated concentrations of the stressor in parts per million= ppm) (parent
imidacloprid + IMI-olefin and IMI-5-OH compounds) in varied crops, plant parts and application
procedures based on radioactivity data ..................................................................................................... 62
Table 4-6. Attractiveness of crops for the registered foliar uses of imidacloprid to bees (as indicated by
USDA, 2014). Note, the potential for off-field exposure is indicated from all foliar uses. ........................ 64
Table 4-7. Attractiveness of crops for the registered soil uses of imidacloprid to bees (as indicated by
USDA, 2014) ................................................................................................................................................ 65
Table 4-8. Attractiveness of crops for the registered seed treatment uses of imidacloprid to bees (as
indicated by USDA, 2014) ........................................................................................................................... 66
Table 4-9. Summary of contact and dietary exposure estimates for foliar applications, soil treatment,
seed treatments, and tree trunk injections of pesticides for Tier I risk assessments. ............................... 69
Table 4-10. Summary of estimated food consumption rates of bees. ...................................................... 70
Table 4-11. Summary of available registrant submitted foliar application residue studies ...................... 75
Table 4-12. Summary of available registrant submitted soil application residue studies ......................... 79
Table 4-13. Summary of the soil application residue studies evaluated from the open literature .......... 84
Table 4-14. Summary of the registrant submitted seed treatment application residue studies .............. 87
Table 4-15. Summary of residue data from imidacloprid-treated seed studies evaluated from the open
literature. .................................................................................................................................................... 92
Table 4-16. Summary of the registrant-submitted combined application method residue studies (soil
application + foliar spray) ........................................................................................................................... 95
Table 4-17. Summary of the registrant submitted combined application method residue studies (seed
treatment + foliar spray) ............................................................................................................................. 96
Table 4-18. Distribution of samples from corn fields according to their concentration of imidacloprid
(Bonmatin, 2005) ........................................................................................................................................ 99
Table 4-19. Distribution of residues from corn and sunflower pollen according to their concentration of
imidacloprid (Bonmatin, 2007) ................................................................................................................... 99
Table 5-1. Summary of endpoints to be used in screening-level and refined Tier I risk estimation ..... 103
Table 5-2. Summary of registrant submitted adult acute contact toxicity studies (all studies tested Apis
mellifera) ................................................................................................................................................... 104
Table 5-3. Summary of adult acute contact toxicity studies to Apis bees evaluated from the open
literature ................................................................................................................................................... 105
Table 5-4. Summary of registrant submitted adult acute contact toxicity studies for non-Apis bees
(Note: both studies concern Bombus terrestris) ....................................................................................... 106
5
Table 5-5. Summary of adult acute contact toxicity studies to non-Apis bees evaluated from the open
literature ................................................................................................................................................... 107
Table 5-6. Summary of registrant submitted adult acute oral toxicity studies (Note: All studies tested
Apis mellifera). .......................................................................................................................................... 110
Table 5-7. Summary of adult acute oral toxicity studies for Apis bees evaluated from the open literature
.................................................................................................................................................................. 111
Table 5-8. Summary of registrant-submitted and evaluated open literature studies assessing the chronic
oral toxicity of imidacloprid to Apis and non-Apis adults. ........................................................................ 115
Table 5-9. Summary of results from Abbott et al., 2008 examining the effects of imidacloprid TGAI on
larval development of blue orchard bees (Osmia lignaria) .1 (Note: Study classified as qualitative) ....... 119
Table 5-10. Summary of acute oral toxicity studies testing the degradates of imidacloprid in the open
literature ................................................................................................................................................... 120
Table 5-11. Summary of chronic adult oral toxicity studies with urea metabolite and 6-CNA (all studies
conducted with Apis mellifera) ................................................................................................................. 122
Table 5-12. Summary of semi-field (feeding) studies available from the open literature (Apis)1 ........... 130
Table 5-13. Summary of semi-field (Tunnel) studies available from the open literature (Bombus) ....... 141
Table 5-14. Summary of semi-field (feeding) studies available from the open literature (Bombus) ...... 143
Table 5-15. Summary of Tier III (full field) studies available from the open literature for Apis bees ..... 156
Table 5-16. Summary of Tier III (full field) studies available from the open literature for Bombus bees.
.................................................................................................................................................................. 159
Table 5-17. Summary of reported pollinator incident reports that are either associated with
confirmatory residue analysis or registrant submitted ............................................................................ 163
Table 6-1. Attractiveness of crops to bees for the registered foliar uses of imidacloprid....................... 170
Table 6-2. Attractiveness of crops to bees for the registered soil uses of imidacloprid. ........................ 171
Table 6-3. Attractiveness of crops to bees for the registered seed treatment uses of imidacloprid. ..... 172
Table 6-4. Summary of Tier I screening-level RQs for contact exposure resulting from foliar uses of
imidacloprid (screening-level contact on-field) ........................................................................................ 174
Table 6-5. Summary of Tier I screening-level RQs for oral exposure resulting from foliar uses of
imidacloprid (based on model-generated exposure values on-field).4 .................................................... 176
Table 6-6. Summary of Tier I screening-level RQs for oral exposure resulting from soil uses of
imidacloprid (based on model-generated exposure values on-field).4 .................................................... 176
Table 6-7. Summary of labeled use information for seed treatment applications of imidacloprid
(screening-level oral on-field) 4 ................................................................................................................. 177
Table 6-8. Imidacloprid Use Patterns for Crops with or without Specific Application Restrictions ........ 178
Table 6-9. Distance from the edge of the field associated with LOC exceedance, for citrus and pome
fruits, calculated using AgDRIFT v.1.1.1, the Tier I Orchard/Airblast module, and app rate of 0.25 lbs.
a.i./A. ......................................................................................................................................................... 179
Table 6-10. Citrus and Pome Fruits: Tier II aerial applications, boom height 10 ft, wind speed 15 mph
(label required), non-volatile rate 0.25 lbs./A, spray volume 5 gal/A ...................................................... 180
Table 6-11. Citrus and Pome Fruits: Tier II aerial applications, boom height 10 ft, wind speed 10 mph
(label required), non-volatile rate 0.25 lbs./A, spray volume 5 gal/A ...................................................... 180
Table 6-12. Globe artichoke (only ground apps allowed): Tier I ground applications, high boom height
(50 inches), application rate 0.126 lbs. a.i./A, 90th percentile results ..................................................... 181
6
Table 6-13. Globe artichoke (only ground apps allowed): Tier I ground applications, low boom height
(20 inches), application rate 0.126 lbs. a.i./A, 90th percentile results ..................................................... 181
Table 6-14. Stone fruit, Tree nuts: Tier II aerial applications, boom height 10 ft, wind speed 15 mph
(label required), non-volatile rate 0.10 lbs./A, spray volume 25 gal/A (label required for these crops) . 181
Table 6-15. Stone fruit, Tree nuts: Tier II aerial applications, boom height 10 ft, wind speed 10 mph,
non-volatile rate 0.10 lbs./A, spray volume 25 gal/A (label required for these crops). ........................... 182
Table 6-16. Tuberous & Corm Vegetables and Certain Other Crops: Tier II aerial applications, boom
height 10 ft, wind speed 15 mph (label required), non-volatile rate 0.04 lbs./A, spray volume 5 gal/A . 182
Table 6-17. Tuberous & Corm Vegetables and Certain Other Crops: Tier II aerial applications, boom
height 10 ft, wind speed 10 mph, non-volatile rate 0.04 lbs./A, spray volume 5 gal/A ........................... 183
Table 6-18. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for foliar applications on citrus fruits (oranges) based on measured residue data.................................. 184
Table 6-19. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen and nectar from foliar-applications to oranges.1,4 ................................. 185
Table 6-20. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for foliar applications on cherries based on measured residue data ....................................................... 186
Table 6-21. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen and nectar from foliar-applications to cherries1,4 .................................. 186
Table 6-22. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for foliar applications on cotton based on measured residue data.......................................................... 187
Table 6-23. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in nectar from foliar-applied cotton1,4 .................................................................. 188
Table 6-24. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for soil applications on tomatoes based on measured residue data. ....................................................... 189
Table 6-25. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen from soil-applications to tomatoes1,4 ..................................................... 189
Table 6-26. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for soil applications on melons based on measured residue data. .......................................................... 190
Table 6-27. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen and nectar from soil-applications to melons.1,4 ..................................... 191
Table 6-28. Summary of the refined acute and chronic estimated environmental concentrations (EECs)
for soil applications to citrus based on measured residue data. .............................................................. 192
Table 6-29. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in nectar from soil applications to citrus1,4............................................................ 193
Table 6-30. Summary of the refined acute and chronic EECs in pollen and nectar following soil
applications to blueberries based on measured residue data. ................................................................ 194
Table 6-31. Summary of Tier I oral RQs for honey bees using refined exposure estimates with measured
total imidacloprid residues in pollen and nectar following soil applications to blueberries1,4 ................ 194
Table 6-32. Summary of the refined acute and chronic EECs for soil applications to strawberries based
on measured residue data. ....................................................................................................................... 195
Table 6-33. Summary of Tier I oral RQs for honey bees using refined exposure estimates with measured
imidacloprid residues in pollen from soil applications to strawberries1,4 ................................................ 196
Table 6-34. Summary of the refined acute and chronic EECs for soil applications on cotton based on
measured residue data. ............................................................................................................................ 197
7
Table 6-35. Summary of Tier I oral RQs for honey bees using refined exposure estimates with measured
total imidacloprid residues in pollen and nectar from soil-applications to cotton.1,4 .............................. 197
Table 6-36. Summary of the refined acute and chronic EECs for seed treatment applications on corn
based on measured residue data.............................................................................................................. 198
Table 6-37. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen and nectar from seed-treated corn1,4 ..................................................... 199
Table 6-38. Summary of the refined acute and chronic EECs for combined (soil + foliar) applications to
tomato based on measured residue data ................................................................................................. 200
Table 6-39. Summary of Tier I oral RQs for honey bees using refined exposure estimates with measured
imidacloprid residues in pollen from combined soil + foliar-applications to tomatoes.1,4 ....................... 201
Table 6-40. Summary of the refined acute and chronic EECs for combined (soil + foliar) applications to
cotton based on measured residue data. ................................................................................................. 202
Table 6-41. Summary of Tier I oral RQs for honey bees using refined exposure estimates with total
imidacloprid residues in pollen and nectar from soil + foliar-applied cotton1,4 ....................................... 202
Table 6-42. Summary of the refined acute and chronic EECs for combined (seed + foliar) applications on
cotton based on residue data ................................................................................................................... 203
Table 6-43. Summary of Tier I oral RQs for honey bees using refined exposure estimates with measured
imidacloprid residues in pollen and nectar from combined seed + foliar applications to cotton.1,4 ....... 203
Table 6-44. SLUA data for imidacloprid and citrus fruits (2004-2013) ................................................... 210
Table 6-45. SLUA data for imidacloprid and stone fruits (2004-2013) ................................................... 214
Table 6-46. SLUA data for imidacloprid and oilseed crops (2004-2013)1 ............................................... 219
Table 6-47. SLUA data imidacloprid and use patterns registered for additional foliar and soil use
patterns (2004-2013) with no available residue data............................................................................... 224
Table 6-48. Summary of risk findings for the foliar applied use patterns of imidacloprid with available
residue data. ............................................................................................................................................. 225
Table 6-49. SLUA data for imidacloprid and fruiting vegetables (2004-2013) ......................................... 226
Table 6-50. SLUA data for imidacloprid and cucurbit vegetables (2004-2013) .................................... 230
Table 6-51. SLUA data imidacloprid and berries/small fruit (2004-2013) .............................................. 239
Table 6-52. SLUA data for imidacloprid on soil only registered use patterns (2004-2013). (Note: Data are
available for soil treated cucurbit vegetables and therefore is not presented below since its SLUA data is
shown in the soil treated melon discussion.............................................................................................. 250
Table 6-53. Summary of risk findings for the soil applied use patterns of imidacloprid with available
residue data. ............................................................................................................................................. 251
Table 6-54. SLUA data imidacloprid and cereal grains (2004-2013)1 ....................................................... 252
Table 6-55. SLUA data imidacloprid and other non-cereal grain seed treatment uses (2004-2013)1 ..... 257
Table 6-56. Summary of risk findings for the seed treatment use patterns of imidacloprid. ................. 258
Table 6-57. Summary of risk findings for the combined method use patterns of imidacloprid. ............. 270
Table 6-58. Comparison of oral exposure to pollen and nectar for adult Apis and Non-Apis bees1 ...... 279
Table 6-59. Comparison of oral exposure to pollen and nectar for larval Apis and Non-Apis bees1 ....... 279
Table 6-60. Comparison of imidacloprid acute contact toxicity to Apis and non-Apis bees ................. 280
Table 6-61. Comparison of imidacloprid acute oral toxicity to Apis and non-Apis bees ......................... 280
Table 7-1. Summary of risk findings for honey bees (Apis mellifera) for the registered use patterns of
imidacloprid .............................................................................................................................................. 289

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Table of Figures
Figure 2-1. Conceptual model for risk assessment of foliar spray applications of imidacloprid to honey
bees. Red depicts systemic pathways. Dashed lines represent routes of exposure that are not
considered major. ....................................................................................................................................... 30
Figure 2-2. Conceptual model for risk assessment of soil applications of imidacloprid to honey bees. Red
depicts systemic pathways. Dashed lines represent routes of exposure that are not considered major. 31
Figure 2-3. Conceptual model for risk assessment of planting of imidacloprid-treated seeds to honey
bees. Red depicts systemic pathways. Dashed lines represent routes of exposure that are not
considered major. ....................................................................................................................................... 32
Figure 2-4. Tiered approach for assessing risk to honey bees from foliar spray applications .................... 35
Figure 2-5. Tiered approach for assessing risk to honey bees from soil/seed applications ....................... 36
Figure 4-1. Imidacloprid application and processes involved in bee exposure .......................................... 46
Figure 4-2. Imidacloprid expected accumulation in 10 years of repeated application at a rate of 0.5 lb.
a.i/A (This rate is equal to 0.245 ppm distributed on the top 6” of the soil); Noting that the graph was
constructed based on yearly application coupled with daily degradation based on the aerobic soil
degradation rate constant. ......................................................................................................................... 50
Figure 4-3. Expected degradation profile for imidacloprid in compartments of the terrestrial
ecosystems. Imidacloprid parent, and the IMI-olefin and IMI-5-OH degradates are considered residues
of toxicological concern. ............................................................................................................................. 53
Figure 4-4. Comparison of up-take data obtained for imidacloprid applied to soil and that applied to
foliage in potatoes ...................................................................................................................................... 58
Figure 4-5. Suggested Imidacloprid degradation profile in plants (based on submitted plant metabolism
data). ........................................................................................................................................................... 61
Figure 5-1. Scatterplot of adult acute contact toxicity of Apis and non-Apis bees from registrant-
submitted and open literature sources conducted with technical grade active ingredient (TGAI) and
formulated typical end product (TEP) imidacloprid. Red circle denotes endpoint used for Tier I risk
estimation purposes. ................................................................................................................................ 109
Figure 5-2. Scatterplot of adult acute oral toxicity of Apis and non-Apis bees from registrant-submitted
and open literature sources conducted with technical grade active ingredient (TGAI) and formulated
typical end product (TEP) imidacloprid. Red circle denotes endpoint used for Tier I risk estimation
purposes. ................................................................................................................................................... 114
Figure 5-3. Queen Production Data from Whitehorn et al (2012) in Controls (A), Low (B) and High
Exposure Treatments (C). Legend numbers indicate the concentration in pollen and nectar, respectively.
.................................................................................................................................................................. 152
Figure 6-1. Summarization of the potential scenarios warranting a Tier I on and/or off-field risk
assessment. ............................................................................................................................................... 169
Figure 6-2. Summary of acute and chronic RQ values using totality of pollen and nectar residue data
from foliar-applied citrus residue study (MRID 49521301). ..................................................................... 211
Figure 6-3. Imidacloprid nectar residues in nectar from foliar-applied citrus study (MRID 49521301,
trials NT005 and NT006 only) as compared to effect levels in registrant submitted colony feeding study
(MRID 49510001). ..................................................................................................................................... 212
Figure 6-4. Imidacloprid average residues in pollen from foliar-applied citrus study (MRID 49521301,
trials NT005 and NT006 only). .................................................................................................................. 213
9