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

OFFICE OF CHEMICAL SAFETY AND

POLLUTION PREVENTION



# 2016 Addendum to the Environmental Fate and Ecological Risk Assessment for Sulfoxaflor Registration

Sulfoxaflor: A 50:50 Mixture of Diastereomer 1 and 2

Prepared by: Keith G. Sappington . M.S. Mohammed A. Ruhman, Ph.D.

Reviewed by: Mah Shamim, Ph.D. United States Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch V 1200 Pennsylvania Ave.

Mail Code 7507P Washington, D.C. 20460

### 1 

## Contents

1. Executive Summary

................................ ................................ ................................ ............... 2

2. Risk Assessment Approach

................................ ................................ ................................ ... 2

3. Pesticide Exposure Potential of Bees

................................ ................................ ................... 3

3.1 Potential for On

- Field Exposure

................................ ................................ ...................... 5

3.2 Potential for Off

- Field Exposure (Spray Drift)

................................ ................................ 5

4. Tier 1 Risk Estimation (Default Exposure)

................................ ................................ ......... 5

4.1 Summary of Tier 1 Bee Toxicity Data

................................ ................................ ............. 6

4.2 On

- Field Risk (Contact and Oral Exposure)

................................ ................................ .... 7

4.3 Off

- Field Risk (Contact With Spray Droplets)

................................ ................................ 7

4.4 Off

- Field Risk (Contact With Residues On Foliage)

................................ ....................... 8

4.5 Off

- Field Risk from Oral Exposure (Pollen and Nectar)

................................ ................. 9

5. Refined Tier 1 Risk Assessment

................................ ................................ ......................... 10

5.1 Off

- Field Risk from Oral Exposure (Refined)

................................ ............................... 10

6. Tier 2 Risk Characterization

................................ ................................ .............................. 12

7. Ecological Incident Reports

................................ ................................ ................................ 13

8. Environmental Persistence of Sulfoxaflor in Bee Relevant Matrices

............................. 13

9. Uncertainty Associated with Lack of Tier 1 Chronic Data for Bees

............................... 15

10. Risk Assessment Conclusions, Assumptions, and Uncertainty

................................ .... 16

11. Additional Recommended Data

................................ ................................ ...................... 18

Appendix A. Forager

- Collected Pollen and Nectar Residues of Sulfoxaflor and Associated Acute Oral RQs From the Cotton Tunnel Study (MRID 48755606).

................................ ........... 19

Appendix B

. Bounding Analysis of the Potential for Chronic (Tier 1) Oral Risks to Adult Bees

................................ ................................ ................................ ................................ ....................... 22

### 2 

## 1. Executive Summary

This Addendum summarizes the ecological risks associated with the proposed Section 3 registration of Transform ® 

### WG and Closer ® 

### SC ( active ingredient: s ulfoxaflor) for use on various crops as a foliar spray and was conducted in accordance to revised labels dated May 5, 2016. The revised labels reflect numerous changes relative to the original EFED Section 3 assessment ( D382619 ) that include: 1) removal of certain bee attractive crops ( e.g., citrus, cotton, cucurbits, soybean and strawberry; 2) prohibiting applications before or during bloom ( e.g., canola, stone fruits, pome fruits, etc .); and 3) prohibiting use on crops grown for seed production ( e.g., bra ssica, bulb vegetables, leafy vegetables, etc .). Since the 9 th 

### Circuit Court’s decision regarding the prior registration of sulfoxaflor concerned the potential risks to bees, this assessment only

focuses on bees. Potential risks to other taxa are lower or equivalent to that described in the previous Section 3 assessment ( D382619 ) 2 

### , noting that the new labels contain a lower maximum single application rate of 0.09 lb a.i./A (ground or aerial spray) and a maximum annual rate of 0.266 lb a.i./A among all the proposed uses.

On

- Field Risks to Bees. Based on the proposed labels, acute and chronic risks to bees foraging

on the treated field are not indicated

. Lack of exposure of bees on the treated field is presumed

since the proposed crops are either considered unattractive to bees, are harvested prior to bloom, or involve applications that are prohibited until after the bloom period of the crop.

Off

- Field Risks to Bees. As with any foliar spray application, there is potential drift to areas adjacent to the treated field. A spray drift analysis indicates that t he spatial extent of acu te risks beyond the treated field is very limited ( <1

– 12 feet beyond the treated field )

. In the absence of

chronic Tier 1 data for individual bees, a bounding analysis was conducted using acute

- to

chronic ratios. This analysis suggests that estimated c hronic risks are also spatially limited beyond the treated field (2

- 4 6 feet, depending on modeling and toxicity assumptions). In addition to being spatially limited, available data suggest that the temporal extent of acute and chronic risks beyond the trea ted field is also limited to relatively short periods of time ( e.g., half of sulfoxaflor degrades in pollen and nectar within 9 days or less based on the vast majority of residue data). It is noted that the spray drift analysis is considered conservative due to assumptions that plants will be in bloom immediately next to the treated field and that bees will obtain 100% of their diet from this spatially limited area.



## 2. Risk Assessment Approach

Estimating risks to bees associated with the proposed Section 3 use of sulfoxaflor follows the Office of Pesticide Programs’ ( OPP’s ) published guidance entitled: “Guidance for Assessing

Pesticide Risks to Bees ” (USEPA 2014 ) 3



### . This guidance presents an iter ative, tiered process for assessing risks that considers multiple lines of evidence related to exposure and effects of pesticides to bees. In summary, this risk assessment process involves:

2 http://www.regulations.gov/#!documentDetail;D=EPA

- HQ

- OPP

- 2010

- 0889

- 0022

3 USEPA et al . 2014. Guidance for Assessing Pesticide Risks to Bees. https://www.epa.gov/pollinator

protection/pollinator

- risk

- assessment

- guidance

### 3 1. Estimating the potential for exposure of bees to the pesticide f or each of the proposed

uses; 2. Conducting a Tier 1 risk assessment based on default ( h igh

- end ) exposure estimates for those uses where a reasonable potential for exposure exists ; 3. C onducting a refined Tier 1 risk assessment based on measured residues in poll en and nectar; and

, 4. E valuating risks based on higher

- t ier ( Tier 2 or Tier 3) colony level

- effects data (as necessary)

.



## 3

. Pesticide Exposure Potential of Bees

The first step in this process involves a qualitative assessment of the potential for exposure of bees to the pesticide. Th e exposure potential of bees is determined by the application method, timing, location ( e.g., indoor vs. outdoor), attractiveness of the crop to bees, agronomic practices ( e.g., timing of harvest), the availability of alternative forage sources and label restrictions regarding applications during the crop bloom period. Primary routes of exposure include interception of spray droplets (contact) and ingestion of contaminated pollen and nectar (oral).

Based on the labels submitted to the Agency on May 5, 2016 , t he proposed uses of sulfoxaflor involve ground or aerial foliar spray applications with medium or coarser spray nozzles ( as defined by the American Society of Agricultural an d Biological Engineers ; ASABE ). For each of the proposed crops or crop groups, information on the ir attractiveness to bees , maximum application rates , and label restrictions re garding the blooming period is summarized in Table 1

. Information on the crop a ttractiveness was derived from the U.S. Department of Agriculture (USDA 2015 4 

### ).

4 USDA. 2015. Attractiveness of Agricultural Crops to Pollinating Bees for the Coll ection of Nectar and/or Pollen

. http://www.ree.usda.gov/ree/news/Attractiveness_of_Agriculture_crops_to_pollinating_bees_Report

- FINAL. pdf

### 4 Table 1

. Summary of Crop Attractiveness to Honey Bee s (HB) and Bumble Bees (BB) and Proposed
Application Rates for Sulfoxaflor

Crop or Crop Group Bee Attractiveness 1 and
Agronomic Practices B l oom
Restrictions 2 Max

. Non

- Bloom Appl. Rate 3

Brassica leafy
vegetables High, but usually harvested

before bloom (except for
small acreage used for seed production)

Applications

n ot allowed

for seed
production

CLOSER TM

0.09 x 2 (consecutive) @ 7d (0.266)

TRANSFORM TM

0.086 x 2 (consecutive) @ 7d
(0.266) Bulb vegetables*

Leafy vegetables (except Brassica) and

watercress Moderate to High for some
members, but usually

harvested before bloom (except for small acreage used for seed production) Leaves of root and
tuber vegetables

Root and tuber vegetables (1A & 1B)

Pome fruits High (apples require managed bee pollination)

Only post

bloom
applications

are allowed Small fruit vine climbing (except fuzzy kiwi fruit)
and low growing berry (except strawberry) Moderate to High (blueberry,
blackberry, raspberry require managed pollination)

Stone fruits High (cherries require managed bee pollination)

Tree nuts and pistachio High (requires managed pollination; almond)

Turf Grass (commercial only) Not attractive N/A

Ornamentals High (assumed) Only post

bloom
applications

are allowed CLOSER TM

0.09 x 2 (consecutive) @ 14 d
(0.266)

TRANSFORM TM

0.086 x 2 (consecutive) @ 14 d (0.266)

Fruiting vegetables and

okra Moderate (HB) High (BB) (managed pollination for seed production) Only post

bloom
applications

are allowed CLOSER TM

0.07 x 2 (consecutive) @ 7 d
(0.266)

TRANSFORM TM

0.071 x 2 (consecutive) @ 7 d
(0.266)

Potatoes (1C and 1D) Moderate (BB only) Only post

bloom
applications

are allowed CLOSER TM

0.07 x 2 (consecutive) @ 14 d
(0.266)

TRANSFORM TM

0.071 x 2 (consecutive) @ 14 d (0.266) Succulent, edible
podded, dry beans Moderate to High

Barley, triticale, wheat Not attractive N/A CLOSER TM

0.043 x 2 / @ 14 d (0.0 86 )

TRANSFORM TM

0.047 x 2 / @ 14 d (0.09)

### 5 Crop or Crop Group Bee Attractiveness 1 and
Agronomic Practices B l oom
Restrictions 2 Max

. Non

- Bloom Appl. Rate 3

Canola High (commercial pollination used for hybrid seed production) Only post

bloom
applications

are allowed CLOSER TM

& TRANSFORM®

0.023 x 2 @ 14 d (0.046)

1 Bee attractiveness based on USDA (2015)

2 N/A = bloom application restrictions are not applicable because crop is not considered bee attractive

3 Maximum single application rate in bold ( lb a.i./A ) ; max. # of consecutive apps; minimum appl. interval, and

total annual application rate in parentheses. * label for CLOSER specifies no more than 3 applications/year and no restrictions on consecutive applications



### 3 **.1 Potential for On** 

**- Field Exposure** 

Based on the i nformation summarized Table 1 and USDA’s assessment of crop attractiveness to

bees

, the proposed uses of sulfoxaflor are not expected to result in significant exposure of

bees on the treated field. This conclusion is reached based on the following conside rations:

1. The c rops are not considered attractive to bees ( e.g., b arley, triticale, wheat, turf

grass ) ;

2. The crops are h arvested before b loom and no application is allowed for seed production ( e.g., b rassica, leafy vegetables, bulb vegetables, root/tubers, leaves of root/tubers (except potato); or

3. The crops are attractive but applications are only allowed after bloom ( e.g., c anola,

o rnamentals pome fruits, potato, stone fruits, tree nuts/pistachio, small fruit v ine climbing & low growing berry [ except strawberry & kiwi ]

, and s ucculent, edible & podded dry

beans ).

**3 .2**  **Potential for O ff** 

**- Field Exposure (Spray Drift)** 

T he OPP bee risk assessment guidance primarily focuses on exposures and risks of bees on the

treatment site . However, w ith outdoor spray applications, there is the potential for off

- site spray drift and subsequent exposure of bees that may be foraging on blooming plants adjacent to the treated site. Therefore, off

- site exposure of bees (oral and contact) as a result of spray drift is also considered possible for all of the proposed use s of sulfoxaflor

.



## 4

. Tier 1 Risk Estimation (Default Exposure)

By design, the initial (default) Tier 1 assessment relies on conservative (high end) estimates of exposure via contact and oral routes. For contact exposure, only the adult (forager) life stage is considered since this is the relevant life stage for honey bees. Furthermore, toxicity protocols have only been developed for acute exposures via the contact route . For the oral route , exposur e

### 6 estimates for bees are compared to acute and chronic toxicity endpoints for both adult and larval bees. These toxicity endpoints are defined by laboratory exposures to groups of individual bees.

**4 .1**  **Summary of Tier 1 Bee Toxicity**  **Data**

For sulfoxaflor , the Tier 1 laboratory toxicity database is complete for contact exposure and for acute larval and adult oral exposure. Acceptable data are not available for estimating chronic effects of sulfoxaflor on larval and adult honey bees. In order to estimate the uncertainty associated with the lack of chronic effects data for adult bees, an acute

- to

- chronic ratio approach was used, as described in Section 9

. It is noteworthy that larval honey bees are much less acutely sensitive to oral exposure (7

- d LD 50 

### > 0. 2 μg a.i./bee ) compared to adults LD 50 

### (48

- h): 0. 0515 ug a.i./bee . C ompared to honey bees, sulfoxaflor appears much less toxic on an acute contact basis to bumble bees, but is of similar acute oral toxicity. D etails of the Tier 1 toxicity test results

with sulfoxaflor are found in the previous Section 3 new chemical risk assessment ( D 382619 ).

Table 2. Tier 1 toxicity test results for sulfoxaflor and bees

Taxa Species Type of Toxicity (Purity) (1) Toxicological Endpoint MRID

Terrestrial

Invertebrates Honey bee, adult ( Apis mellifera) Acute (contact) TGAI LD 50 (72

- h): 0.379 ug a.i./bee 47832102 (Acceptable)
Acute (contact) TEP:

GF

- 2032

- SC LD 50 (48

- h): 0.130 ug a.i./bee 47832419 (Acceptable)
Acute (contact) TEP:

GF

- 2372

- WG LD 50 (48

- h): 0.224 ug a.i./bee 47832511 (Acceptable)

Acute (oral) TGAI LD 50 (48

- h): 0.146 ug a.i./bee 47832103 (Acceptable)
Acute (oral) TEP: GF

2032

- SC LD 50 (48

- h): 0.05 15 ug a.i./bee 47832417 (Acceptable)
Acute (oral)

X11719474 LD 50 (96

- h): > 100 ug a.i./bee 47832107 (Acceptable)
Acute (oral)

X11721061 LD 50 (48

- h): >104 ug a.i./bee 48445809

Acute foliar residue
( TEP: GF

- 2372

- WG) 24

- h aged residue
mortality: 14% ( 0.089 lb ai/A or 100 g ai/ha)
15% ( 0.178 lb ai/A or 200 g ai/ha) 47832512 (Acceptable)

Acute foliar residue
( TEP: GF

- 2032

- SC) 3

- h aged residue
mortality: 4% (200 g ai/ha) 47832420 (Acceptable)

Honey bee, larvae

( Apis mellifera) Acute , single dose (TGAI) LD 50 (7

- d): >0.2 μg a.i./bee 48755602 (Supplemental)

Chronic, repeated dose (TGAI) NOAEC (7

- d): 0.02 μg a.i./bee ; LOAEC (7

- d) =
0.2 μg a.i./bee 48755603 (Supplemental)

Bumble bee, adult ( Bombus terrestris) Acute (contact) (TEP:

GF

- 2032

- SC ) LD 50 (72

- h): 7.55 μg a.i./bee 47832418 (Supplemental)

### 7 Taxa Species Type of Toxicity (Purity) (1) Toxicological Endpoint MRID

Acute (oral) (TEP: GF

2032

- SC ) LD 50 (72

- h): 0.027 μg a.i./bee 47832418 (Supplemental) The most sensitive endpoints shown in bold a re used for risk estimation.



### 4

**. 2**  **On**

**- Field Risk**  **( Contact**  **and Oral Exposure**  **)**

As d iscussed previously in Section 3 .1

, exposure of bees on the treated field is not expected

. Therefore, the potential for risk to bees potentially foraging for pollen and nectar on the

treated field is considered highly unlikely

.

**4 .3**  **Off**

**- Field Risk**  **( Contact**  **With Spray Droplets)**

In addition to bees foraging on the treated field, bees may also be foraging on blooming plants adjacent to the treated fields. In these situations, bees may become exposed through interception

of pesticide spray droplets that drift off site during applic ation. In order to estimate the potential

contact exposure of bees to sulfoxaflor when foraging on plants adjacent to treated fields, AgDRIFT (version 2.1.1) was run based on available label information. For ground and aerial (non

- ULV) applications, the label specifies that only medium or coarser spray nozzles shall be used. Furthermore, the label specifies a boom height of < 4 ft for ground applications and < 10 feet for aerial applications

. For wind speed, the labels prohibit application above a wind spe ed of

1 0 mph.

Results of AgDRIFT modeling for off

- site deposition of spray droplets at the maximum proposed application rate of 0.0 9 lb a.i./A for CLOSER TM 

### are shown in Table 3

. Since the drift of ground and aerial sprays declines exponentially with distance from the treated field, t he highest off

- field exposures occur at the near edge of treated fields

. Based on AgDRIFT modeling with the maximum application rate of 0.09 lb a.i./A and the Tier 1 acute contact risk assessment presented earlier, the acu te risk LOC is exceeded for bees potentially foraging in sites ranging up

to 2 to 1 2 feet from the treated field , depending on the application method . For this analysis, “medium to coarse” spray nozzles with a median droplet diameter of 341 μm was assumed

.

### 8 Table 3

. Equivalent S ulfoxafl or Application Rates Predicted b y AgDRIFT a t Various Distances from t he
Application Site for t he Maximum Application Rate o f 0.09 Lb A.I./ A. and Distance from Treated Field
Beyond Where the Acute Risk Level of Concern for Bees (Contact Exposure) is Exceeded.

Method Droplets Dv0.5 (μm) Distance from the field and point estimate of application rate (lb a.i./A) Distance From Field Edge

Where the

Acute Risk LOC

is Exceeded 3
(ft) 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.0041 0.0022 0.0013 0.0007 0.0004 2

Aerial 2 M to C 341 0.0205 0.0142 0.0096 0.0053 0.0024 1 2

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)

1 B oom height = 4.2 ft,

2 boom height = 10 ft, wind speed = 10 mph, spray volume 3 gal/A

3 D istance to LOC of 0.4 which equates to an application rate of 0.019 lb a.i./A for CLOSER TM b ased on a 48

- h acute

contact LD 50 of 0.130 μ g a.i./bee for (MRID 47832419) and a contact dose of 2.7 μ g a.i./bee per 1 lb a.i./A.



### Based on the a cute contact toxicity of CLOSER TM



### , the acute risk LOC is met at an application

rate of 0.019 lb a.i./A. Using all of the application rates of CLOSER TM 

### which exceed this rate,

the distance from the field edge where the acute risk LOC of 0.4 would be exceeded was determined using AgDRIFT ( Table 3 ). The other formulated product (TRANSFORM TM 

### ) is roughly 50% less toxic on an acute contact exposure basis than CLOSER TM 

### ; therefore, the

distances at which the acute contact risk LOC is exceeded will be shorter than those shown in

Table 4 for CLOSER TM



### .

Table 4

. Distance from the Treated Field Where the Acute Risk LOC ( Contact Exposure ) is Exceeded f or Various Application Rates o f Sulfoxaflor a s Determined b y AgDRIFT

Method Droplets Dv0.5 (μm) Distance From Field Edge Where the Acute Contact Risk LOC

is Exceeded 3 (ft)
0.023 lb ai/A 0.043 lb ai/A 0.07 lb ai/A 0.09 lb ai/A

Ground 1 M/C 341 < 1 <1 2 2

Aerial 2 M to C 341 <1 <1 5 1 2

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle , (M to C assumes a median droplet diameter of 341 μm)

1 B oom height = 4.2 ft

2 B oom height = 10 ft, wind speed = 10 mph, spray volume 3 gal/A

3 D istance (round to nearest ft) to LOC of 0.4 which equates to an application rate of 0.019 lb a.i./A for

CLOSER TM b ased on a 48

- h acute contact LD 50 of 0.130 μ g a.i./bee for (MRID 47832419) and a contact dose of

2.7 μ g a.i./bee per 1 lb a.i./A.

.



### 4.4 **Off**

**- Field Risk (Contact With**  **Residues On Foliage )** 

B ees may come into dermal contact with pesticide residues that have deposited on to foliage when they are foraging on attractive plants adjacent to the treated field. For sulfoxaflor, data are

### 9 available from two studies that examined the toxicity of residues on treated foliage . These studies were conducted according to the Office of Chemical Safety and Pollution Prevention (OCSPP) test guideline 850.3020, as summarized in the previous Section 3 risk assessment ( D382619 ). The toxicity of residues on foliage studies assess the toxicity of aged residues on

treated alfalfa

. Based on aged residues of the CLOSER TM 

### formulation ( GF

- 2032

- SC ) on alfalfa

a fter application a t 200 g/ha (0.18 lb a.i./A)

, less than 5% mortality occurred following 3 to 24

hours of exposure (MRID 47832420). With the TRANSFORM TM 

### formulation ( GF

- 2372

- WG ) at the same application rate , up to 15% mortality occurred following exposure to alfalfa aged from

3

- 24 hours (MRID 47832512)

. Collectively, these studies suggest that aged residues of these two sulfoxaflor formulations result in low mortality to honey bees via dermal contact with treated foliage, i.e ., the compounds exhibit low “residual toxicity”. It is further noted that th e application rate used in these studies (0.18 lb a.i./A) is double the maximum single application

rate of sulfoxaflor proposed for this registration (0.09 lb a.i./A).

**4.5 Off** 

**- Field Risk**  **from Oral Exposure (Pollen and Nectar)** 

Bees may also become expose d to sulfoxaflor which has been deposited on ( or translocated into ) pollen and nectar of blooming plants adjacent to treated fields. In order to provide an estimate of the potential oral exposure of bees to sulfoxaflor when foraging on plants adjacent to treated fields, AgDRIFT (version 2.1.1) was run as described previously in Table 4 for the acute contact exposures. Based on this AgDRIFT modeling and default (high end) estimates of exposure for adult nectar foragers (the highest exposed type of honey bee)

, the acute risk LOC is exceeded

from 16 to 361 feet beyond the edge of the treated field, depending on the application rate and application method ( Table 5 ). Since these RQ values exceed t he LOC using default (high end) exposure assumptions , they are refined further in Section 5 using available information on

residues of sulfoxaflor in pollen and nectar of applicable crops.

Table 5

. Distance f rom the Treated Field Edge Where t he Acute Risk LOC Is Exceeded for Adult Nectar

Foragers ( Default

, Oral Exposure ) a s Determined Using AgDRIFT

Method Droplets Dv0.5 (μm) Distance From the Treated Field Edge Where the Acute

Contact Risk LOC is Exceeded 3 (ft)
0.023 lb ai/A 0.043 lb ai/A 0.07 lb ai/A 0.09 lb ai/A

Ground 1 M/C 341 16 36 6 6 89

Aerial 2 M to C 341 135 210 295 36 1

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle (M to C assumes a median droplet diameter of 341 μm)

1 boom h eight = 4.2 ft ;;

2 boom height = 10 ft, wind speed = 10 mph, spray volume 3 gal/A ;

3 distance (round to nearest ft) to LOC of 0.4 which equates to 0.0007 lb ai/A for default (high end) oral

exposure.

### 10 

## 5

. Refined Tier 1 Risk Assessment

The Tier 1 risk assessment summarized in Section 4 reflects default assumptions of exposure estimates of honey bees to the pesticide. By design, the initial Tier 1 risk assessment reflects simplified, high end estimates of exposure in order to quickly identify uses which pose minimal

risk to bees. However, LOC exceedances that are based on the default (high end) estimates of exposure in Section 4 do not necessarily mean that risk will occur. In such cases, refinement of

default estimates of exposure may be conducted using more realistic estimates o f exposure that

reflect the residues from actual use pattern s of the chemical. A cute contact risks are based on the highest measured value of acute contact exposure reported for honey bees in various field trials

based on the work of Koch and Wei s ser (199 7) 5



### . Currently, EPA does not have standard methods for refining screening

- level acute contact exposure estimates. For oral exposure,

refinement of Tier 1 risk estimat es is possible based on consideration of different bee castes and tasks (each differing in their nectar and pollen consumption rates) and consideration of measured values of pesticide residues in pollen and nectar. Section 5 .1 present s the findings of the refined

on

- field and off

- field risk estimates for acute, oral exposure of bees to sulfox aflor. As previously discussed, acceptable Tier 1 toxicity data are not available from which to estimate chronic toxicity of sulfoxaflor to adult or larval honey bees. The uncertainty associated with this lack of

data is characterized in Section 4

.

**5 .1**  **O ff** 

**- Field Risk**  **from Oral Exposure (Refined)**

For sulfoxaflor, pollen and nectar residue data are available from multiple studies including a field residue study with cotton (MRID 48755606), pumpkin (MRID 48755601)

, and Phacelia (MRID 48446601 and 48445806). Maximum reported residues of sulfoxaflor in various plant

and hive matrices are shown in Table 6

. Among the available residue studies, t he highest residues reported in pollen and nectar resulted from the cotton study . Furt hermore, the cotton study also included measurements made directly from foraging bees ( i.e ., pollen collected by bees) returning to the hive , which is considered a more representative measure of exposure of honey bee colonies compared to the other matrices ( e.g ., pollen collected directly from flowers)

in which residues were measured

. For these reasons, the residue value s measured in pollen and nectar from foraging bees in the cotton study were considered most appropriate among the

available data for furth er refining the estimates of oral exposure of bees to sulfoxaflor. Details of these studies are provided in the previous Section 3 risk assessment ( D 382619)



### .

5 Koch, H. and P. Weisser. 1997. Exposure of honey bees during pesticide application under field conditions. Apidologie

, 28 : 439

- 447.

### 11 Table 6 . Maximum Reported Residues ( p pm) o f Sulfoxaflor i n Plant a nd Hive Materials f rom Various

Field Studies

Application

Rate (lb

a

. i

. /A) Plant

Pollen Plant

Nectar Plant

Tissue Forager

Nectar* Forager

Pollen * Comb

Pollen Comb

Larvae MRID

Cotton

1 x 0.045 1.26 0.13 0.22 0.03 <0.01

48755606 2 x 0.045 2.54 0.05 0.83 0.04 0.01

2 x 0.089 6.66 0.07 2.78 1.19 0.03

2 x 0.134 c 2.61 1.01 2.23 0.04 0.08

Phacelia

1 x 0.021 0.52 b 0.05 0.29 48446601

1 x 0.043 1.48 b 0.09 0.81

Phacelia

1 x 0.006 0.06 a

48445806 1 x 0.012 0.04 a

1 x 0.021 1.76 b 0.61 a

1 x 0.045 0.23 a

1 x 0.088 1.01 a
Pumpkin

1 x 0.022 0.08 0.03 0.20 b 48755601

1 x 0.089 0.38 0.03 1.27 b

a Samples taken 7 days after treatment rather than immediately after treatment

b Whole plant samples in study MRID 48446601, flower samples in study MRID 48445806, leaf tissue in study

MRIID 48755601

. c Not considered in the current risk assessment since the single application rate (0.134 lb a.i./A) exceeds the maximum single rate for the proposed Section 3 (0.0 9 lb a. i./A)

. * Used for refining default estimates of oral exposure of bees to sulfoxaflor. Shaded cells indicate no data are available for the applicable matrix.



### For the three treatments from the cotton residue study that correspond to currently proposed labe l

rates summarized in Table 6 (1 x 0.045, 2 x 0.045 and 1 x 0.089 lb a.i./A) , a total of 132

individual samples of forager

- collected pollen and nectar (66 paired samples) were obtained during the 10

- d ay exposure during which time the hives remained in the tunnels ( Table A

- 1, Appendix A ) . For each of these 66 paired samples of residues in pollen and nectar, an acute oral RQ value was calculated based on consumption rates for adult nectar foragers (highest nectar exposure) and adult nur se bees (highest pollen exposure). Of the 132 acute RQ values calculated, only 4 exceed the acute risk LOC of 0.4 ( Table A

- 2, Appendix A ). The highest acute oral RQ value determined from these paired residue values is 0.72 for adult nectar foragers ( Day

1

, 1 x 0.045 lb ai/A treatment ) and 0.72 for nurse bees (Day 0, 2 x 0.089 lb ai/A treatment)

. These acute oral RQ values slightly exceed the acute risk LOC of 0.4. Notably, the maximum acute RQ value for larval bees (0.08) does not exceed the acute risk LOC.

However, these RQ values assume that bees are foraging on the treated field, which is not expected to occur. Therefore, A g DRIFT modeling was conducted to estimate the distance from

the treated field where the acute risk LOC of 0.4 would be exceeded

. Bees may be foraging near the edges of these fields due to the presence of weeds or other attractive plants. The maximum

### 12 acute oral RQ of 0.72 was assumed to occur at the edge of the treated field. T o estimate the corresponding reduction in thi s RQ as a function of distance from the treated field, this RQ was multiplied by the proportion of the on

- field application rate estimated using AgDRIFT at various distances from the treated field edge ( see Table 3 ) for each of the modeling scenarios. The

results

, shown in Table 7 , indicate that the acute, oral RQ values for adult bees are below the

acute risk LOC of 0.4 at less than 1 foot from the edge of the treated field regardless of modeling scenario chosen. Notably, t he spatial extent to which the acute oral RQ may be exceeded adjacent to the treated field appears to be very small relative to the spatial extent of floral resources that would likely be available to bees further away from the treated field.

Table 7 . Re fined Tier 1 Acute, Oral RQ Values for Honey Bees at Varying Distances Off the Treated

Field



## 6

. Tier 2 Risk Characterization

The T ier 2 characterization of pesticide risks to bees involves evaluating effects of the pesticide

on the entire colony. This is important to risk assessment because effects at the individual level may not result in similar (if any) effects at the colony level. In addition, evaluating effects at the colony level integrates multiple mechanisms by which a toxicant can affect the proper functioning of a colony ( e.g., behavior abnormalities, navigation, and learning) which may not be indicated by individual

- level effects data.

As described previously, no acute or chronic risks are expected on the treated fi elds because of lack of exposure based on the lack of crop attractiveness to bees, agronomic practices and label restrictions for application only after the bloom period. However, there was exceedance of the acute risk LOC of 0.4 at short distances beyond the treated field (up to 12 feet for contact exposure and about 1 f oot for oral exposure) for adult bees.

Based on label information described earlier , the predicted spray drift application rate of sulfoxaflor at 10 feet beyond the field margin would ra nge from 0.005 lb a.i./A (assuming 0.023

lb a.i./A applied on the field) to 0.021 lb a.i./A (assuming 0.09 lb a.i./A applied on the treated field). Furthermore, there would be an expected exponential decline in these application rates with increasing distance from the treated field ( Table 4 ). Method Droplets Dv0.5 (μm) Refined Maximum Acute Oral RQ at Varying

Distances from the Treated Field Distance From the Treated Field Edge

Where the Acute Oral

Risk LOC is

Exceeded 3 (ft) 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.03 0.02 0.01 0.01 0.00 < 1

Aerial 2 M to C 341 0.16 0.11 0.08 0.04 0.02 < 1

Table Notes: M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)

1 boom height = 4.2 ft

2 boom height = 10 ft, wind speed = 10 mph, spray volume 3 gal/A

3 distance (round ed to nearest ft) to LOC of 0.4 which equates to an estimated drift fraction of 56% beyond the field edge (i.e., a 56% reduction of the refined on

- field RQ of 0.72).

### 13 As described in the previous Section 3 risk assessment, a total of 6 T ier 2 semi

- field (tunnel) studies were submitted as part of the original new chemical registration. In these studies, effects

observed on mo rtality, flight activity and behavioral abnormalities were short

- lived (3 days or less). No sustained effects were observed on parameters such as forager mortality, flight activity, behavior abnormalities and hive strength at the application rates predict ed at 10 feet or more beyond the field margin

. It is noted that the application rates predicted within 10 feet of the field margin are at the low end of the rates evaluated in the submitted Tier 2 semi

- field studies and rates at 20 feet are typically belo w the tested rates. Therefore, exposure considered in the Tier 2 tunnel studies are most applicable to regions immediately adjacent to the downwind portion of the treated field margin. Short

- term effects on brood were not evident compared to

controls ; how ever
, due to deficiencies in the study execution and/or design, the potential effects on brood over longer

- time periods could not be conclusively determined.



## 7

. Ecological Incident Reports

According to EPA’s Ecological Incident Information System, one ecological incident was reported to EPA on 1/2/2014 that purportedly involved three insecticides: acephate, dichrotophos, and sulfoxaflor. A beekeeper in Dunklin County, MO stated f rom June thr ough August, crops (including watermelon) we re treated with pesticides , including Bidrin [dichrotophos], a cetate, and su lfoxaflor as well as tank mixes of a variety of chemical products. The beekeeper reported that o ver 1,000 hives were affected by the pe sticide use , which is listed as “incapacitation” in the EIIS database

. There is no information on how many other pesticides may have been use, the legality of the use, the timing of p esticide application, presence or absence of other potential stressors ( e.g., Varroa, Nosema ) or data confirming that pesticide exposure actually occurred ( e.g., residues of pesticides in bees or the hive ) . Use of the pesticides was not confirmed independently. Given the limited information associated with this incident report and the apparent application of multiple pesticides, link ing these reported effects to any one pesticide is not possible. No other incidents potentially associated with sulfoxaflor use over the past several years (either from Section 18 emergency u ses on cotton, sorghum, alfalfa or from the previously registered Section 3) have been reported to the Agency.



## 8

. Environmental Persistence of Sulfoxaflor in Bee Relevant

Matrices

In addition to the spatial scale associated with off

- field risks to bees described earlier ( e.g., 12 feet or less beyond the field edge for acute risk), it is also important to consider the temporal scale of risks ( i.e., how long bees may be exposed to sulfoxaflor )

. To characterize the temporal

scale of risk, available data w ere evaluated on how long it takes for sulfoxaflor residues in pollen and nectar to dissipate. Specifically, dissipation half

- life values (DT 50 

### ) were determined for

sulfoxaflor residues measured in pollen and nectar from the cotton tunnel study ( Table 8 a nd Figure 1 ). The median and 90 th 

### percentile DT 50 

### values of sulfoxaflor in cotton pollen and nectar are 2.3 and 8.6 days, respectively. These values indicate that sulfoxaflor has a relatively short persistence in cotton pollen and nectar.

### 14 Table 8

. Compilation of dissipation half

- life values for sulfoxaflor in cotton pollen and nectar

Application Number 1 Application Rate (lb a.i./A) DT 50 (days)

Pollen Collected From Plants

1 0.045 < 1

1 0.045 3.3

2 0.045 1

1 0.089 1.3

2 0.089 2.5

1 0.134 n.d.

2 0.134 5.5

Pollen Collected from Forager Bees

1 0.045 4

1 0.045 2.6

2 0.045 1.7

1 0.089 2.3

2 0.089 11.6

1 0.134 1.2

2 0.134 69

Nectar Collected From Forager Bees

1 0.045 2.1

1 0.045 2.1

2 0.045 1.7

1 0.089 2

2 0.089 6.6

1 0.134 8.3

2 0.134 6.9

1 Number refers to the first or second consecutive application (MRID 48755606)

### 15 Figure 1 . Cumulative frequency of DT50 values for sulfoxaflor in cotton pollen and nectar (MRID 48755606)



### Although these data are for only one crop, a similar rapid decline in sulfoxaflor residues is

observed in Phacelia pollen and nectar (MRID 48476601) where approximately 10% of the residues measured on day 0 remained by day 6 . DT 50 

### values were not determin ed because only three measures were available over time (days 0, 5 and 6).



## 9

. Uncertainty Associated with Lack of Tier 1 Chronic Data for

Bees

Although the potential for chronic (Tier 1) risks to individual bees foraging immediately adjacent to treated fields is not known due to lack of chronic adult Tier 1 data, a bounding analysis was conducted to estimate the uncertainty associated with lack o f chronic toxicity data. This bounding analysis relies on the use of “acute

- to

- chronic ratios” (ACRs) derived from other nicotinic acetylcholine receptor (AChR) agonists to estimate a chronic No Observed Adverse Effect Level (NOAEL) for adult bees. The A CR is determined as the ratio of the acute oral LD 50 

### to the chronic oral NOAEC for adult bees. Data for AChR agonists are considered most applicable to sulfoxaflor given similarities in the mode of action in insects.

Currently, d ata from which to derive A CRs for oral exposure of adult bees with AChR agonists are available for imidacloprid, clothianidin, and flupyradifurone ( Table B

- 1 of Appendix B )

. The calculated ACR values are 24.4 (imidacloprid), 10.3 (clothianidin) and 2.6 (flupyradifurone)

with an ove rall mean ACR of 12.4. Using a mean ACR value of 12.4, a “central tendency”

estimate of 0.0041 μg a.i./bee/d was determined the adult chronic oral NOAEL. Using the maximum ACR of 24.4, an adult chronic oral NOAEL of 0.0021 μg a.i./bee/d was determined

an d was subsequently used for calculating an “upper bound” estimate of chronic risk.

### 16 T he estimated NOAEL of 0.0021 and 0.0041 μg a.i./bee/d were used to calculate upper bound and central tendency estimates of chronic Tier 1 risks, respectively, to adult nurse bees and nectar foragers. Nurse bees and nectar foragers consume the largest amounts of pollen and nectar, respectively, and would provide the greatest estimates of risk. Using each set of daily average concentrations sulfoxaflor in cotton pollen a nd nectar ( Table A

- 1 of Appendix A )

combined with the estimated NOAEL of 0.0021 μg a.i./bee/d , maximum chronic oral RQ values

of 10.0 (nurse bees) and 8.8 (nectar foragers) are calculated as upper bound estimates of risk 6


### Similarly, using the mean estimated NOAEL of 0.0041 μg a.i./bee/d and the same set of residue data, maximum chronic oral RQ values of 5.1 (nurse bees) and 4.5 (nectar foragers) are calculated as central tendency estimates of risk.

However, these chronic oral RQ values assume that bees are foraging on the treated field, which is not expected to occur. Therefore, A g DRIFT modeling was conducted to estimate the distance

from the treated field where the chronic risk LOC of 1.0 would be exceeded

. The maximum chronic RQ values described previously were assumed to occur at the edge of the treated field.

T o estimate the corresponding reduction in th ese RQ values as a function of distance from the treated field, each RQ was multiplied by the proportion of the on

- field application rate estimated using AgDRIFT at various distances from the treated field edge ( see Table 3 ) for each of the modeling scenarios. This analysis indicates that the potential for chronic (Tier 1) oral risks bees foraging adjacent to the trea ted fields would extend from 2

- 1 4 feet beyond the treated field assuming a central tendency estimate of the chronic oral NOAEL ( Tables B

- 2 and B

- 3 of Appendix B ) and label restrictions on ground and aerial application . Potential chronic oral risks

to adult bees would extend from 4

- 4 6 feet beyond the treated field assuming the lower estimate of the chronic NOAEL (0.0021 μg a.i./bee/d ; Tables B

- 4 and B

- 5 of Appendix B ).

Although not without important caveats, this bo unding analysis suggests that chronic Tier 1 risks may be of concern over a relatively small distance beyond the treated (2

- 4 6 feet, depending on modeling and toxicity assumptions). Importantly, the use of an ACR value to estimate chronic

NOAEL introduces uncertainty into the risk estimate due to the considerable variability observed in the ACR values (range: 2.6 to 24.4). However, t h is bounding analysis is also considered highly conservative because it assume s that bees would obtain 100% of their diet fr om the relatively narrow contaminated area beyond the treated field s . Furthermore, the duration of exposure is likely to be relatively short based on the relatively short persistence of sulfoxaflor in pollen and nectar described previously.



## 10

. Risk Ass essment Conclusions, Assumptions, and Uncertainty

In consideration of multiple lines of evidence described in the previous sections, the following

risk conclusions ar e reached for bees

.

6 As indicated in the Agency’s recently published bee risk assessment with imidacloprid, use of daily average

residu es of pesticides is considered appropriate for estimating chronic Tier 1 risks to bees https://www.regulations.gov/#!docketBrow ser;rpp=25;so=DESC;sb=postedDate;po=0;dct=SR;D=EPA

HQ

- OPP

- 2008

- 0844 )

### 17 1. A cute and chronic risks on the treated field are not indicated

. For all of the proposed

uses, acute and chronic risks to bees are considered low for bees potentially foraging on the treated field since significant exposure is not expected. Lack of exposure is presumed since crops are considered unattractive to bees, are harvested prior to bloom, or because applications are prohibited until after the bloom period of the crop.

2. The spatial extent of acute risks beyond the treated field is very limited

. For all of the proposed uses of sulfoxaflor, acute oral and contact risk to bees which may forage immediately adjacent to the treated fi eld during ( or shortly after ) application is limited to

< 1

– 12 fe et beyond the treated field

. Therefore, a spray drift buffer of 12 feet would be expected to mitigate acute risk to bees that may be foraging in this zone adjacent to

treated fields.

3. A bounding analysis suggests that estimated chronic risks are also spat ially limited beyond the treated field. A bounding analysis using estimated values of chronic toxicity to adult bees suggests that chronic Tier 1 risks may be of concern over a relatively small distance beyond the treated (2

- 4 6 feet, depending on modeling and toxicity assumptions).

4. Temporal extent of acute and chronic risks beyond the treated field is limited . Data on the persistence of sulfoxaflor in pollen and nectar suggests that residues will degrade relatively quickly (90% of the half

- life values are approximately 9 days or less and 50% are approximately 2 days or less ).

A number of assumptions and uncertainties are noted in the preceding risk assessment. These

include:

1. Off

- Field Diet/ Forage Habitat

. Off

- field (Tier 1) risk assessment assum es that bees will be foraging in the spray drift zone adjacent to the treated field and that they obtain 100% of their diet from blooming plants in this zone. This assumption likely overestimate s exposure and off

- field risk because plants will not always be in bloom

, and when they are in bloom, not all plants will be attractive to bees . Furthermore, honey bees often forage opportunistically on a variety of forage sources across the landscape (up to 5 miles from the hive)

.

2. Residue Profile in Pollen and Nect ar. Refined risk estimates for oral exposure used for estimating on

- field and off

- field risks assume that residues of sulfoxaflor in pollen and

nectar of flowering plants are equivalent to the maximum residues measured in pollen and nectar of cotton, which occurred within two days of foliar application. Among the three plant species for which residue data are available, the greatest residues in pollen and nectar were observed with cotton. Furthermore, foliar applications to cotton were made during the bloo ming period which would tend to maximize residues in pollen and nectar for this crop. Since not all plants inhabiting the acute and chronic spray drift zone beyond the field edge will be blooming, residues in non

- blooming plants will be subject to dissipat ion prior to the bloom period which will lead to reduced residues during bloom (median foliar dissipation half

- life = 2.3 days)

. However, since the species of plant adjacent to the treated field cannot be predicted with certainty, it is possible that

### 18 sulfo xaflor residues in cotton could be higher or lower than residues in blooming plants adjacent to the treated field immediately following pesticide application.

3. Lack of Tier 1 Chronic Toxicity Data. No Tier 1 risk assessment was conducted to

assess chronic exposures because acceptable chronic Tier 1 data are not available for

sulfoxaflor for adult or larval bees. If sulfoxaflor has a similar toxicity profile as imidacloprid in terms to its ACR, then the chronic (Tier 1) risk could potentially extend

to 4 6 f eet beyond the treated field (aerial applications). If sulfoxaflor has a toxicity profile similar to the mean ACR of imidacloprid, clothianidin, and flupyradifurone, then chronic (Tier 1) risk could potentially extend up to 1 4 feet beyond the treated fiel d. It is noted that OPP has only recently been requiring chronic Tier 1 bee toxicity data since the publication of its bee risk assessment guidance in 2014 as more reliable test protocols have been developed for such tests.



## 11

. Additional Recommended Dat a

Based on the proposed uses of sulfoxaflor, which are not expected to result in exposure of bees on the treated field and are expected to result in very limited off

- field exposure, additional data pertaining to bees is not requested at this time. It is noted, however, that additional chronic Tier 1 data would help to reduce uncertainty in the bounding analysis of spray drift for estimating chronic risk. These additional Tier 1 data (and possibly higher tier exposure and effects data) would likely be nee ded in the future in order to evaluate any new (proposed) uses of sulfoxaflor that result in significant exposure of bees.

### 19 

## Appendix A

Forager

- Collected Pollen and Nectar Residues of Sulfoxaflor and
Associated Acute Oral RQs From the Cotton Tunnel Study (MRID 48755606).

### 20 Table A

- 1. Forager

- Collected Pollen and Nectar Residues from the Cotton Tunnel Study (MRID 48755606)

Application Rate (lb a.i./A) Forager

- Collected Pollen (μg ai/kg) Forager

- Collected Nectar (μg ai/kg) Day

Pollen Nectar

H1 H2 Average H1 H2 Average

0.045 0 127.40 187.40 157.40 32.67 21.70 27.19

--- 1 122.00 144.80 133.40 126.40 1.51 63.96

--- 2 150.40 52.27 101.34 8.32 2.05 5.18

--- 3 222.30 81.86 152.08 5.00 0.64 2.82

--- 4 120.10 72.60 96.35 5.00 1.29 3.15

--- 5 102.40 33.68 68.04 16.05 0.28 8.16

--- 6 66.40 68.61 67.51 8.05 1.05 4.55

--- 7 18.66 37.63 28.15 3.95 0.82 2.39

--- 8 32.24 55.96 44.10 3.02 0.72 1.87

--- 9 29.88 58.37 44.13 1.93 0.07 1.00

--- 10 49.22 12.63 30.93 1.64 0.16 0.90

0.045 0 225.90 173.00 199.45 9.53 8.68 9.11

--- 1 124.10 224.50 174.30 21.21 16.68 18.95

--- 2 96.70 125.40 111.05 29.71 8.39 19.05

--- 3 143.80 271.50 207.65 15.51 11.23 13.37

--- 4 81.74 32.62 57.18 11.10 3.70 7.40

0.045 5 829.50 192.40 510.95 48.97 44.96 46.97

--- 6 229.10 296.00 262.55 26.46 14.38 20.42

--- 7 271.80 145.00 208.40 41.96 8.70 25.33

--- 8 84.01 146.90 115.46 14.63 7.09 10.86

--- 9 68.00 32.23 50.12 8.03 5.36 6.69

--- 10 55.89 83.13 69.51 6.28 4.55 5.41

0.089 0 2782.00 512.20 1647.10 73.78 2.52 38.15

--- 1 242.60 350.10 296.35 25.94 22.67 24.31

--- 2 250.80 298.60 274.70 11.89 19.33 15.61

--- 3 99.52 116.00 107.76 8.59 3.59 6.09

--- 4 191.90 102.60 147.25 3.94 16.96 10.45

0.089 5 796.60 1146.00 971.30 22.87 21.86 22.37

--- 6 393.60 400.00 396.80 21.97 33.65 27.81

--- 7 320.20 2262.00 1291.10 12.80 19.74 16.27

--- 8 255.20 371.30 313.25 8.85 31.46 20.16

--- 9 113.20 317.00 215.10 5.21 11.54 8.38

--- 10 117.80 1323.00 720.40 10.24 35.52 22.88
H1 = hive 1, H2 = hive 2 (two hives per tunnel) ; values in bold indicate the paired residue values that
resulted in the highest acute oral RQ to nectar foragers and nurse bees

### 21 Table A

- 2

. Acute oral RQ values calculated for Nurse Bees and Nectar Foragers Based on the Cotton Tunnel Study (MRID 48755606)

Application Rate (lb a.i./A) Nurse Bee Acute Oral RQ Nectar Forager Acute Oral RQ Day

H1 H2 H1 H2

0.045 0 0.11 0.09 0.19 0.12

--- 1 0.37 0.03 0.72 0.01

--- 2 0.05 0.02 0.05 0.01

--- 3 0.06 0.02 0.03 0.00

--- 4 0.04 0.02 0.03 0.01

--- 5 0.06 0.01 0.09 0.00

--- 6 0.03 0.02 0.05 0.01

--- 7 0.01 0.01 0.02 0.00

--- 8 0.01 0.01 0.02 0.00

--- 9 0.01 0.01 0.01 0.00

--- 10 0.01 0.00 0.01 0.00

0.045 0 0.07 0.06 0.05 0.05

--- 1 0.08 0.09 0.12 0.09

--- 2 0.10 0.05 0.17 0.05

--- 3 0.07 0.08 0.09 0.06

--- 4 0.05 0.02 0.06 0.02

0.045 5 0.29 0.16 0.28 0.26

--- 6 0.11 0.09 0.15 0.08

--- 7 0.16 0.05 0.24 0.05

--- 8 0.06 0.05 0.08 0.04

--- 9 0.03 0.02 0.05 0.03

--- 10 0.03 0.03 0.04 0.03

0.089 0 0.72 0.10 0.42 0.01

--- 1 0.12 0.13 0.15 0.13

--- 2 0.08 0.11 0.07 0.11

--- 3 0.04 0.03 0.05 0.02

--- 4 0.05 0.07 0.02 0.10

0.089 5 0.21 0.27 0.13 0.12

--- 6 0.13 0.17 0.12 0.19

--- 7 0.09 0.48 0.07 0.11

--- 8 0.07 0.15 0.05 0.18

--- 9 0.04 0.09 0.03 0.07

--- 10 0.05 0.34 0.06 0.20 H1 = hive 1, H2 = hive 2 (two hives per tunnel); RQ values in bold /shaded cells exceed the

acute risk LOC of 0.4

### 22 

## Appendix B

Bounding Analysis of the Potential for Chronic (Tier 1) Oral Risks to

Adult Bees

### 23 Table B

- 1. Data Considered for Estimation of the Adult Chronic Oral NOAEL for Sulfoxaflor

.

Chemical (IRAC
Class) [ACR] Structure MW (g/mol) Kow Vapor

Pressure Aerobic

Soil

DT50 Acute & Chronic
Adult Endpoints 1

Sulfoxaflor (4C) 277 6 Low Rapid (2

- 8 d) LD 50 =0.0515 μg ai/bee/d (MRID

47832417 )

Estimated Chronic

NOAEL = 0.0021

- 0.0041 μg ai/bee/d
(using Max ACR

of 24.4 and mean

ACR of 12.4

, respectively )
Imidacloprid (4A)

(ACR=24.4) 255 3.7 Low 200 d to

> 1 yr LD 50 =0.0039 μg ai/bee/d (MRID
42273003)

Chronic NOAEL =
0.00016 μg ai/bee/d (MRID
49750601)

Clothianidin (4A)

(ACR =10.3) 250 1.1 Low > 1 year LD 50 =0.0037 μg ai/bee/d (MRID

45422426 )

Chronic NOAEL =
0.00036 μg ai/bee/d (MRID

48414901 )

Flupyradifurone (4D)

(ACR = 2.6) 288 1.2 Low 35 d

- >1

yr LD 50 =1.2 μg ai/bee/d (M RID 48843722)

Chronic NOAEL = 0.464 μg ai/bee /d
(MRID 48843762 )

### 24 Table B

- 2

. Upper Bound Estimates of Chronic (Tier 1) Risks to Adult Nurse Bees

Method Droplets Dv0.5 (μm) Upper Bound Chronic RQ s for Nurse Bees @ spray drift

distances from the field edge Distance to

chronic LOC 3 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.4 6 0.25 0.15 0.08 0.06 5

Aerial 2 M to C 341 2. 3 1. 6 1. 1 0.59 0. 2 7 4 6

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)
1 boom height = 4.2 ft, On

- Field Chronic RQ of 10.0 estimated using max. ACR of 24.4 2 boom height = 10 ft, wind speed = 10 mph, non

- volatile rate 0.09 lb a.i./A, spray volume 3 gal/A

3 distance to LOC of 1.0 wh ich equates to a 10% drift fraction based on a maximum estimated chronic oral RQ of

10.0 for nurse bees with an estimated chronic adult NOAEL of 0.0021 ug a.i./bee/d

.



### Table B

- 3

. Upper Bound Estimates of Chronic (Tier 1) Risks to Adult Nectar Foragers

Met hod Droplets Dv0.5 (μm) Upper Bound Chronic RQ s for Nectar Foragers @ spray drift

distances from the field edge s Distance to

chronic LOC 3 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.40 0.2 2 0.1 3 0.0 7 0.0 5 4

Aerial 2 M to C 341 2.0 1. 4 0.94 0.52 0.2 4 3 5

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)
1 boom height = 4.2 ft, On

- Field Chronic RQ of 5.1 estimated using max. ACR of 24.4
2 boom height = 10 ft, wind speed = 10 mph, non

- volatile rate 0.09 lb a.i./A, spray volume 3 gal/A

3 distance to LOC of 1.0 which equates to a n 1 1.3 % drift fraction based on a maximum estimated chronic oral RQ of 8.8 for nectar foragers with an estimated chronic adult NOAEL of 0.0021 ug a.i./bee/d

.



### Table B

- 4

. Central Tendency Estimates of Chronic (Tier 1) Risks to Adult Nurse Bees

Method Droplets Dv0.5 (μm) Central Tendency Chronic RQ for Nurse Bees @ spray drift

distances from the field edge Distance to

chronic LOC 3 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.23 0.1 3 0.07 0.04 0.0 3 2

Aerial 2 M to C 341 1.2 0.80 0.54 0.30 0.1 4 1 4

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)
1 boom height = 4.2 ft, On

- Field Chronic RQ of 4.5 estimated using max. ACR of 24.4
2 boom height = 10 ft, wind speed = 10 mph, non

- volatile rate 0.09 lb a.i./A, spray volume 3 gal/A

3 distance to LOC of 1.0 which equates to a 1 9.6 % drift fraction based on a maximum estimated chronic oral RQ

of 5.1 for nurse bees with an estimated chronic adult NOAEL of 0.0041 ug a.i./bee/d

.

### 25 Table B

- 5

. Central Tendency Estimates of Chronic (Tier 1) Risks to Adult Nectar Foragers

Method Droplets Dv0.5 (μm) Central Tendency Chronic RQ for Nectar Foragers @ spray drift

distances from the field edge Distance to

chronic LOC 3 10 ft 20 ft 40 ft 80 ft 150 ft

Ground 1 M/C 341 0.2 1 0.11 0.0 7 0.0 4 0.0 3 2

Aerial 2 M to C 341 1.0 0.71 0.48 0.2 7 0.12 11

Table Notes:
M = medium spray nozzle, C = coarse spray nozzle

, (M to C assumes a median droplet diameter of 341 μm)
1 boom height = 4.2 ft, On

- Field Chronic RQ of 10.0 estimated using max. ACR of 24.4 2 boom height = 10 ft, wind speed = 10 mph, non

- volatile rate 0.09 lb a.i./A, spray volume 3 gal/A

3 distance to LOC of 1.0 which equates to a 22 % drift fraction based on a maximum estimated chronic oral RQ of
4.5 for nectar foragers with an estimated chronic adult NOAEL of 0.0041 ug a.i./bee/d

.