### U N ITED STATES ENVIRONMENTAL P R OTECTION AGE N CY

W AS HIN GTON, D

. C

. 2 0460



### Date: August 8, 2013 OF F IC E OF CH E MI C A L S AFE T Y

AN D POLL U TI ON PRE V ENT I ON



### Subject: 2,4

- D. Occupationa l and Resident i a l Exposure Assessment for a P roposed Use of
2,4-D Cho l ine on H e r bici d e -T olerant Corn and Soybean

PC Code: 03000 I

, 05 1 505

Dec i s i o n No. : 

## · q'l19f l

Petit i o n No.: NA

R i sk Assessment Type: OccupationaVResidential Exposure Assessment

TXR No.: NA



### MRTD No.: NA



### Fro m : Alexandra LaMay, B i ologist

Ri sk Assessment Branch VII DP Ba r code : 0413002 Reg i stration No.: NA Regulatory Action: Section 3

Case No.: NA

CAS No

. : 94-75

- 7

40 CFR: 40 CFR 180.142



### T h ro u gh: Health Effects Division (750

1 

### 9P) 

# 0--

Michael Metzger, Chief

# ' / 

# J 

# a# .J

Risk Assessment Branch V 

# tuf-. (

Health Effects Division (7 09P)

and

Matthew Crowley, Bio l og i st Margari t a Co ll an t es, B iolbg i s**/)c?~** 

### Exposure Sc i ence Advisory Comm i ttee (ExpoSAC) 

### I HED



### To: Michael Walsh Regi s tration Division (7505P)



### Introd u ction

The Registration Divis i on ( RD) 

### req u ested that the Health E ffects Divis io n (HED) conduct an

exposure and risk assessment for the new use of2,4-D choline on herbicide-tolerant com and soybean.



## It is 

## HED policy to use the best availab l e data to assess exposure. Several sources of 

## generic

data were used in this assessment as su rr ogate d ata in t h e absence of chemical-spec i fic data,

Page I of35

### including Pesticide Handlers Exposure Database Version 1

. 1 (PHED 1.1 ); the Agricultural

Handler Exposure Task Force (AHETF) database; the Outdoor Residen tial Exposure Task Force
(ORETF) database; and the Residential SOPs. Some of these data are proprietary, and subject to
the data protection prov i s i ons of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA).

Note: Th is memorandum was reviewe d by the Exposure Science Advisory Committee (ExpoSAC) on June 13, 2013.

Page 2 of35Page 3 of 35 

### Table of Contents

1.0 Executive Summary

................................ ................................ ................................ ............. 4

2.0 Risk Assessment Conclusions and Recommendations

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

2.1 Summary of Risk Estimates

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

2.2 Label Recommendations from Occupational Assess ment

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

2.3 Label Recommendations from Residential Assessment

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

2.4 Data Deficiencies and Requirements

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

3.0 Hazard Characterization

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

4.0 Use Profile

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

5.0 Residential Exposure and Risk Estimates

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

5.1 Residential Handler Exposure/Risk Estimates

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

5.2 Residential Post

- application Exposure/Risk Estimates

................................ .................. 11

5.2.1 Residential Post

- application Exposure for Turf Use

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

5.2.2 Residential Post

- application Exposure for Aquatic Use

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

5.3 Combined Residential Risk Estimates (Multiple Exposure Scenarios)

......................... 14

5.4 Residential Risk Estimate s for Use in Aggregate Assessment

................................ ...... 14

5.5 Spray Drift

................................ ................................ ................................ ...................... 17

5.6 Volatiliza tion

................................ ................................ ................................ .............. 17

5.6.1 Flux Data

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

5.6.2 Volatilization Modeling and Risk Assessment

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

5.6.3 Volatilization Risk Estimates

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

6.0 Occupational Exposure and Risk Estimates

................................ ................................ ...... 21

6.1 Occupational Handler Exposure/Risk Estimates

................................ ............................ 21

6.2 Occupational Post

- application Exposure/Risk Estimates

................................ .............. 23

6.2.1 Occupational Post

- application Inhalation Exposure/Risk Estimates

...................... 24

6.2.2 Occupational Post

- application Dermal Exposure/Risk Estimates

.......................... 24 Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

..................... 25 Appendix B. Flux Rates and Flux Profiles

................................ ................................ ................... 34Page 4 of 35



### 1.0 Executive Summary

2,4

- Dichlorophenoxyacetic acid (2,4

- D) is an alkylchlorophenoxy herbicide used to control a variety of broadleaf weeds. It is a longstanding active ingredient (ai) registered for a variety of food/feed uses. Permanent tolerances for 2, 4

- D are established under 40 CFR 180.142 for a wide variety of crops and livestock commodities.

The proposed use is for 2,4

- D choline use on herbicide

- tolerant corn and soybean

. These crops

have a trait that that increases the herbicide tolerance of corn and soybean to 2,4

- D via increased metabolism through a pathwa y involving the metabolite 2,4

- dichlorophenol (2,4

- DCP).

For corn, the proposed use is for pre

- plant, pre

- emergence, or post

- emergence (when corn is no later than the V8 growth stage or 48 inches tall) application to herbicide

- tolerant field corn at a

m aximum single application rate of 1.0 lb acid equivalent ( ae ) / acre ( A )

. For soybean, the proposed use is for pre

- plant, pre

- emergence, or post

- emergence (when soybean is no later than

the R2, or full flowering, growth stage) application to soybean at a ma xi mum single application

rate of 1.0 lb ae/A

. For post

- emergence applications for both crops , a maximum of two applications are permitted with a minimum of 12 days between applications. The maximum seasonal application rate is 3 lbs ae/A/season for both crops . The directions indicate no more than one pre

- emergence application and no more than two post

- emergence applications per use season. Applications are to be made using groundboom equipment. Aerial application and chemigation are prohibited. The pr oposed preharvest interval (PHI) for corn and soybeans is 30 days.

T here are registered uses of 2,4

- D on ornamental turf including golf courses and parks as well as aquatic uses ; therefore, residential handler exposure and post

- application exposure to treated turf is possible. As the Residential SOPs were updated in 2012, these scenarios have been re

assessed. There is n o potential hazard via the dermal route f or 2,4

- D, therefo re the handler assessment included only the inhalation route of exposure and the post

- application assessment included only the inhalation and incidental oral route of exposure. The residential handler and

post

- application risk estimates are not of concern for 2,4

- D for all scenarios and all routes of

exposure.

An increase in use of 2,4

- D is anticipated in the near future due to several factors (e.g., resistance traits in certain crops and weed resistance management). Exposure to drift and volatilizatio n
, and the appropriate available data, were considered in this assessment due to the anticipated market expansion. Concerning spray drift, t he residential postapplication exposure assessment for registered use as direct application to turf is protective o f potential deposition on turf from spray drift for the proposed use of 2,4

- D choline on herbicide

- tolerant corn and soybean

. The potential exposure to vapor phase 2,4

- D residues emitted from treated fields for the proposed

use s of 2,4

- D choline has been evaluated in this assessment . Volatilization modeling was completed using Probabilistic Exposure and Risk model for FUMigants ( PERFUM) as well as

chemical

- and formulation

- specific flux data. The results indicate that volatilization of 2,4

- D

from treated crops does occur and could result in bystander exposure to vapor phase 2,4

- D. Results of PERFUM modeling, however, indicate that airborne concentrations, even at the edge of the treated fields, are not of concern.Page 5 of 35



### Occupational handlers may apply 2,4

- D choline with groundboom equipment. There is n o potential hazard via the dermal route f or 2,4

- D, therefore the occupational handler assessment included only the inhalation route of exposure. Occupational handler inhalation risk estimates

are not of concern (i.e., MOEs > LOC of 300) for all scenarios for use of 2,4

- D choline on

herbicide

- tolerant corn and soybean. At baseline PPE (i.e., no respirator), the occupational handler inhalation MOE is 4,900 for mixer/loaders and 3,200 for applicators using groundboom equipment.

There is n o potential hazard via the dermal route f or 2,4

- D ; therefore, a quantitative occupational

post

- application dermal risk assessment was not completed. T he minimum Worker Protection Standard (WPS) restricted entry interval ( REI ) of 48 hours is adequate to protect agricultural workers from post

- application exposures to 2,4

- D

.

Human Studies Review This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pestici de or other chemical. These data, which include studies from PHED 1.1; the AHETF database; the Outdoor Residential Exposure Task Force (ORETF) database; and the Residential SOPs, are (1) subject to ethics review pursuant to 40 CFR 26, (2)

have received that review, and (3) are compliant with applicable ethics requirements. For certain studies, the ethics review may have included review by the Human Studies Review Board. Descriptions of data sources, as well as guidance on their use, can be found at the Agency

website 1



### .

2.0 Risk Assessment Conclusions and Recommendations

2.1 Summary of Risk Estimates

The residential handler and post

- application risk estimates are not of concern for 2,4

- D for all scenarios and all routes of exposure. The residential postapplication exposure assessment for registered use as direct application to turf is protective of potential deposition on turf from spray

drift. The volatilization assessment indicates there are no risks of concern for bystand ers adjacent to treated fields.

Occupational handler inhalation risk estimates are not of concern (i.e., MOEs > LOC of 300) for all scenarios for use of 2,4

- D choline on herbicide

- tolerant corn and soybean. At baseline PPE (i.e., no respirator), the occupational handler inhalation MOE is 4,900 for mixer/loaders and 3,200 for applicators using groundboom equipment. There is n o potential hazard via the dermal

route f or 2,4

- D ; therefore, a quantitative occupational post

- application dermal risk assessment was not completed.

2.2 Label Recommendations from Occupational Assessment

1 http://www.epa.gov/pesticides/science/handler

- exposure

- data.html and http://www.epa.gov/pesticides/science/post

- app

- exposure

- data.htmlPage 6 of 35



### None.

2.3 Label Recommendations from Residential Assessment

None.

2.4 Data Deficiencies and Requirements

Turf Transferable Residue (TTR): In accordance with the updated Part 158 data requirements (2007), a TTR study is required for all occupational (e.g., sod farms, golf courses, parks, and recreational areas) or residential tu rf uses. Acceptable TTR data are available for 2,4

- D. There

is n o potential hazard via the dermal route f or 2,4

- D

.

Dislodgeable Foliar Residue (DFR): In accordance with the updated Part 158 data requirements (2007), one or more DF R stud ies are required when a pesticide has residential or occupational

uses t hat could result in post

- application dermal exposure. A DFR study is not required for 2,4

- D at this time since there is n o potential hazard via the dermal route f or 2,4

- D

.

3 .0 Hazard Characterization

Acute Toxicity

Table 3.0.1

- Acute Toxicity Categories for 2,4

- D 2

Acid Acute Oral (870.1100) III Acute Dermal (870.1200) III Acute Inhalation (870.1300) III Primary Eye Irritation (870.2400) I Primary Skin Irritation (870.2500) IV Dermal Sensitization (870.2600) Not a dermal sensitizer



### Toxicological PODs Used for Risk Assessment

Table 3.0. 2 Summary of Toxicological Doses and Endpoints for 2,4

- D for Use in Occupational and Non

Occupational Human Health Risk Assessments

Exposure/

Scenario Point of

Departure Uncertainty/FQ

PA Safety

Factors RfD, PAD,

Level of

Concern for

Risk

Assessment Study and Toxicological Effects

Acute Dietary (General Population, including

Infants and Children) NOAEL = 67

mg/kg/day UF A = 10x

UF H =10x FQPA SF= 1x aRfD=aPAD =

0.67 mg/kg/day Acute Neurotoxicity Study

– Rat

MRID 43115201 (1994) LOAEL = 227 mg/kg/day based on slight gait abnormalities (forepaw flexing and knuckling) and increased incidence of

incoordination.

2 ORE Assessment for RED. D316596. T. Dole. 5/4/05.Page 7 of 35

Table 3.0. 2 Summary of Toxicological Doses and Endpoints for 2,4

- D for Use in Occupational and Non

Occupational Human Health Risk Assessments

Exposure/

Scenario Point of

Departure Uncertainty/FQ

PA Safety

Factors RfD, PAD,

Level of

Concern for

Risk

Assessment Study and Toxicological Effects

Incidental Oral (1

- 30 days and 1

- 6 months) NOAEL = 21

mg/kg/day UF A = 10x

UF H =10x FQPA SF= 1x Residential

LOC for MOE

= 100 Extended 1

- generation reproduction

( Crl:CD(SD) rat) MRID 47972101 (2010)

LOAEL= 800/600 ppm (males 55.6 mkd; females 46.7 mkd), based on kidney toxicity manifested as increased kidney weights and increased incidence of degeneration of the proximal convoluted

tubules , and for offspring based on decreased body weight observed throughout lactation.

Dermal

Short

- and

Intermediate

Term (1

- 30 days and 1

- 6 months) No potential hazard via the dermal route, based on the lack of systemic effects following repeat

dermal exposure of rabbits at dose levels up to 1000 mg/kg/day. Although developmental toxicity

was not assessed in the dermal study, clear NOAELs (dermal equivalent doses of 250 and 300 mg/kg/day) were determined; the developmental effects occurred at dose levels that exceed renal clearance mechanism (dermal equivalent doses of 750 and 900 mg/kg/day); dose levels re quired to exceed the renal clearance mechanism would not be attained following dermal exposure to humans.

Inhalation

Short

- and

Intermediate

Term ( all durations) L OAEL = 0.05

mL/kg/day

HEC=0.013 mg/L/day A

(residential)

HEC= 0.056 mg/L/day A
(occupational)

HED=1.9 mg/kg/day B

(residential)

HED= 2.68 mg/kg/day B
(occupational) UF A = 3 x

UF H = 10 x FQPA S F = 1x LOAEL→NOAEL = 10 x Residential

and Occupational

LOC for MOE

= 300 Subchronic inhalation toxicity study (SD

CD rat) MRID 47398701 (2008) LOAEL = 0.05 mg/L/day, based on portal

- of

- entry effects (squamous metaplasia and epithelial hyperplasia with increased mixed inflammatory cells within the larynx ); not totally resolved fol lowing a 4

- week recovery period.

Cancer (oral, dermal, inhalation) Classification: Group D

– not classifiable as to human carcinogenicity

Point of Departure (POD) = A data point or an estimated point that is derived from observed dose

- response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = no ob served adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies). UF L = use of a LOAEL to extrapolate a

NOAEL. UF S = use of a short

- term study for long

- term risk assessment. UF DB = to account for the absence of key data (i.e., lack of a critical study). FQPA SF = FQPA Safety Factor. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level of concern. N/A = not applicable.

1 T he HEC used for risk assessment is the most sensitive one derived from the nasal degeneration effects

.

A Residential HEC (portal of entry endpoint) = rat POD * (daily duration adjustment) * weekly duration adjustment * RDDRPage 8 of 35

= 0.05 mg/L * (6 hrs/24 hrs) * (5 days/7 days ) * T racheobronchial RDDR (1.49) = 0. 013 mg/L Occupational HEC (portal of entry endpoint) = rat POD * (daily duration adjustment) * weekly duration adjustment * RDDR = 0.05 mg/L * (6 hrs/8 hrs) * (5 days/5 days ) * T racheobronchial RDDR (1.49) = 0.056 mg/L

B Residential HE D (portal of entry endpoint) = HEC * human specific conversion factor * daily duration

= HE C (0.013 mg/L) * 6.0 L/hr/kg * 24 hrs= 1.9 mg/kg/day Occupational HED (portal of entry endpoint) = HEC * human specific conversion factor * daily duration = HEC (0.056 mg/L) *6.0 L/hr/kg * 8 hrs= 2.68 mg/kg/day



### Absorption

Since the short

- and intermediate

- term inhalation PODs were based on route

- specific toxicity studies, no absorption factors were necessary to estimate inhalation exposure.

Body Weight The standard body weight for the general population (80 kg) was used for all inhalation exposure scenari os covered in this risk assessment since the endpoints selected were not developmental

and/or fetal effects.

4 .0 Use Profile

For corn, the proposed use is for pre

- plant, pre

- emergence, or post

- emergence (when corn is no later than the V8 growth stage or 48 inches tall) application to herbicide

- tolerant field corn at a maximum single application rate of 1.0 lb acid equivalent (ae)/acre (A)

. For soybean, the proposed use is for pre

- plant, pre

- emergence, or post

- emergence (when soybean is no later than

the R2, or full flowering, growth stage) application to soybean at a maxi mum single application

rate of 1.0 lb ae/A

. For post

- emergence applications for both cr ops , a maximum of two applications are permitted with a minimum of 12 days between applications. The maximum seasonal application rate is 3 lbs ae/A/season for both crops . The directions indicate no more than one pre

- emergence application and no more tha n two post

- emergence applications per use season. Applications are to be made using groundboom equipment. Aerial application and chemigation are prohibited. The proposed preharvest interval (PHI) for corn and soybeans is 30 days. The 2,4

- D product labe ls direct mixers, loaders, applicators and other handlers to wear long

- sleeved shirt and long pants, shoes plus socks, chemical

- resistant gloves, and protective eyewear; a chemical

- resistant apron is required when mixing or loading, cleaning up spills or

e quipment, or otherwise exposed to the concentrate.

Table 4 .1. Summary o f Proposed Directions for Use of 2,4

- D Choline

.

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb

ae /A) Max. No.

Applic. per

Season Max.

Seasonal Applic. Rate (lb ai/A) PHI

(days) Use Directions and

Limitations

Herbicide

- Tolerant Soybean s

Groundboom equipment only

Preplant, Preemergence,

and Postemergence Application Liquid

[62719

- AUU] 1 lb

ae/acre 3 3 lb ae/acre

per use

season 30 Do not apply this product through any type of irrigation system. Do not aerially apply this product. Do not apply more than

one preemergence application and no more than two postemergencePage 9 of 35

Table 4 .1. Summary o f Proposed Directions for Use of 2,4

- D Choline

.

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb

ae /A) Max. No.

Applic. per

Season Max.

Seasonal Applic. Rate (lb ai/A) PHI

(days) Use Directions and

Limitations

applications per use season. Do not apply to soybeans

later than the R2 stage.

Herbicide

- Tolerant Corn

Groundboom equipment only

Preplant, Preemergence,

and Postemergence Application Liquid

[62719

- AGO] 1 lb

ae/acre 3 3 lb ae/acre

per use

season Forage:

30 Do not apply this product

through any type of irrigation system. Do not aerially apply this product. Do not apply more than

one preemergence application and no more that two postemergence applications per use season. Do not apply to corn later than the V8 stage or corn

more than 48 inches tall.



### 5 .0 Residential Exposure and Risk Estimates

There are registered residential uses of 2,4

- D for use on ornamental turf, including parks, sports fields, and golf courses , as well as aquatic uses ; these uses have been assessed previously and there are no new residential uses proposed. The existing residential uses that have been reassessed in this document to reflect updates to HED’s 2012 Residential SOPs 3 

### along with policy changes for body weigh t assumptions. The revision of residential exposures will impact the human health aggregate risk assessment for 2,4

- D.

5 .1 Residential Handler Exposure/Risk Estimates

HED uses the term “handlers” to describe those individuals who are involved in the pes ticide application process. HED believes that there are distinct tasks related to applications and that exposures can vary depending on the specifics of each task. Residential handlers are addressed somewhat differently by HED as homeowners are assumed t o complete all elements of an application without use of any protective equipment.

The quantitative exposure/risk assessment developed for residential handlers is based on the following scenarios: Mixing/Loading/Applying Liquid/ WP /DF to Lawns/Turf with Hose

- End Sprayer Mixing/Loading/Applying Liquid/WP in WSP to Lawns/Turf/ Aquatic Sites with Manually

- pressurized handwand Mixing/Loading/Applying Ready

- to

- Use/WP in WSP to Lawns/Turf with Hose

- End Sprayer Mixing/Loading/Applying Liquid to Lawns/Turf / Aquatic Sites with Backpack

3 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.htmlPage 10 of 35



### Mi xing/Loading/Applying Liquid/WP /DF to Lawns/Turf with Manually

- pressurized handwand or backpack Mixing/Loading/Applying Granule to Lawns/Turf with Push

- type spreader, Belly Grinder, Spoon, Shaker Can, Cup or Hand dispersal

Residential Handler Exposure Data and Assumptions A series of assumptions and exposure factors served as the basis for completing the residential handler risk assessments. Each assumption and factor is detailed below.

Application Rate : The maximum appli cation rate for lawns/turf is 1.45 lb ae/acre for registered uses.

Unit Exposures and Area Treated or Amount Handled : Unit exposure values and estimates for area treated or amount handled were taken from HED’s

2012 Residential SOPs 4



### .

Exposure Duration: Residential handler exposure is expected to be short

- term in duration. Intermediate

- term exposures are not likely because of the intermittent nature of applications by homeowners.

Residential Handler Non

- Cancer Exposure and Risk Estimate Equations The algorithms used to estimate exposure and dose for residential handlers can be found in Appendix A and/or the 2012 Residential SOPs 5



### .

Combining Exposures/Risk Estimate s: There is n o potential hazard via the dermal route f or 2,4

- D . Only inhalation risk estimate s were quantitatively assessed

.

Summary of Residential Handler Non

- Cancer Exposure and Risk Estimates

The residential handler risk estimates are not of concern for 2 ,4

- D (MOEs are greater than the level of concern of 300 for inhalation) for all scenarios.

Table 5.1.1. Residential Handler Non

- cancer Exposure a nd Risk Estimates for 2,4

- D

.

Exposure Scenario Level of Concern Inhalation Unit Exposure (mg/lb ai) Maximum

Application

Rate 1 Area Treated or

Amount Handled Daily 2 Inhalation

Dose (mg/kg/day) 3 MOE 4

(LOC = 300)

Mixer/Loader/Applicator

Lawns/Turf, Liquid/

WP /DF, Hose

- end sprayer

Inhalation = 300 0.022 1.5 lb ae/acre 0.5 acres 0.00021 9,200

Lawns/Turf

/ Aquatic Sites

, Liquid/WP in WSP, Manually

- pressurized

handwand 0.018 0.06 lb

ae /gallon A 5 gallons 0.000068 28,000

Lawns/Turf, Ready

- to

use/WP in WSP, Hose

- end 0.034 1.5 lb ae/acre 0.5 acres 0.00032 6,000

4 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html

5 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.h tmlPage 11 of 35

Table 5.1.1. Residential Handler Non

- cancer Exposure a nd Risk Estimates for 2,4

- D

.

Exposure Scenario Level of Concern Inhalation Unit Exposure (mg/lb ai) Maximum

Application

Rate 1 Area Treated or

Amount Handled Daily 2 Inhalation

Dose (mg/kg/day) 3 MOE 4

(LOC = 300)

sprayer

Lawns/Turf

/ Aquatic Sites

, Liquid, Backpack 0.14 0.06 lb ae/gallon A 5 gallons 0.00053 3,600

Lawns/Turf, WP /DF, Manually

- pressurized handwand or Backpack 1.1 0.06 lb ae/gallon A 5 gallons 0.0041 460

Lawns/Turf, Granule, Push

type spreader 0.0026 1.5 lb ae/acre 0.5 acres 0.000024 78,000

Lawns/Turf, Granule, Belly

Grinder 0.039 0.0000344 lb

ai/ft 2 ,B 1200 ft 2 0.00002 94,000

Lawns/Turf, Granule, Spoon 0.087 0.0000344 lb

ai/ft 2 ,B 100 ft 2 0.0000037 510,000

Lawns/Turf, Granule, Cup/

Shaker Can 0.013 0.0000344 lb

ai/ft 2 ,B 100 ft 2 0.00000056 3,400,000

Lawns/Turf, Granule, Hand Dispersal 0.38 0.0000344 lb

ai/ft 2 ,B 100 ft 2 0.000016 120,000

1 Based on registered or proposed label.

2 Based on HED’s 2012 Residential SOPs ( http://www.epa.gov/pesticides/science/residential

- exposure

- sop.html ).

3 Inhalation Dose = Inhalation Unit Exposure (mg/lb ai) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled (A

/day or gallons/day) ÷ BW (kg).

4 Inhalation MOE = Inhal ation POD (mg/kg/day) ÷ Inhalation Dose (mg/kg/day).

A 1.5 lb ai per acre with minimum of 25 gallons used per acre = 0.06 lb ai/gal

B 1.5 lb ai/acre * 1 acre/43560 ft 2 = 0.0000344 lb ai/ft 2



### 5

. 2 Residential Post

- application Exposure/Risk Estimates

There is the potential for post

- application exposure for individuals exposed as a result of being in an environment that has been previously treated with 2,4

- D

. The quantitative exposure/risk

assessment for residential post

- application exposures is based on the following scenarios:

As a result of existing residential uses:

Incidental ingestion (i.e., hand

- to

- mouth, object

- to

- mouth, soil ingestion exposure) from contact with treated turf ( children 1 < 2 years old only) Episodic granular ingest ion on treated turf ( children 1 < 2 years old only)

Incidental i ngestion of water during recreational swimming (both adults and children 3 < 6 years old).

Assessment of post

- application exposure to turf treated with liquid formulations is protective of

ex posure to solid formulations.

The lifestages selected for each post

- application scenario are based on an analysis provided as an Appendix in the 2012 Residential SOPs 6 

### . These lifestages are not the only lifestages that could be potentially exposed for th ese post

- application scenarios; however, the assessment of these

6 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.htmlPage 12 of 35



### lifestages is health protective for the exposures and risk estimates for any other potentially exposed lifestages.

5.2.1 Residential Post

- application Exposure for Turf Use

Residential Post

- application Exposure Data and Assumptions for Turf Use A series of assumptions and exposure factors served as the basis for completing the residential

post

- application risk assessment . Each assumption and factor is detailed in the 2012 Residential

SO Ps 6



### .

Chemical

- specific TTR Data

There are three transferable turf residue studies available for 2,4

- D , MRIDs 45033101, 44655703, and 44655702. T hese studies have been determined to be acceptable for risk

assessment purposes. The highest predicted day 0 TTR value is 0.28 μg/cm 2 

### (from MRID

44655703 , TRT3, North Carolina, application rate of 1.79 lb ae/acre) . For risk assessment purposes, this resi due value is scaled to the 1.45 lb ae/acre application rate; the residue value for risk assessment is 0.23 μg/cm 2 

### on day 0.

Residential Post

- application Non

- Cancer Exposure and Risk Equations The algorithms used to estimate residential post

- application ex posure and dose can be found in Appendix A and/or the 2012 Residential SOPs 6



### .

Combining Exposure and Risk Estimates

There is n o potential hazard via the dermal route f or 2,4

- D . Only incidental oral risk estimate s

were quantitatively assessed

. The incidental oral sc enarios (i.e., hand

- to

- mouth and object

- to

mouth) should be considered inter

- related and it is likely that they occur interspersed amongst each other across time. Combining these scenarios would be overly

- conservative because of the

conservative nature of each individual assessment. The g ranular ingestion scenario is not

combined as this exposure would not occur as a result of routine behavior and is considered an episodic event related to poisoning

. 

### Therefore, no post

- application exposure scenarios were combined for children 1 < 2 years old.

Summary of Residential Post

- application Non

- Cancer Exposure and Risk Estimates for Turf Use The residential post

- application risk estimates are not of concern for 2,4

- D (MOEs are greater

than the level of concern of 100) for all incidental oral scenarios.

Table 5.2.1

. Residential Post

- application Non

- cancer Exposure a nd Risk Estimates for 2,4

- D.

Lifestage Post

- application Exposure

Scenario Application

Rate 1 Dose

(mg/kg/day) 2 MOEs 3 Combined

Routes Combined

MOEs Use Site Route of Exposure

1 to <2 years Turf Hand

- to

- Mouth 1.45 lb

ae/acre 0.0315 670

NA NA Object

- to

- Mouth 0.00096 22,000
Soil Ingestion 4.9x10

- 5 430,000
Episodic Granular Ingestion 3% ai; 1.5 lb

ae/acre 0.14 490 A

1 Based on registered or proposed label

. 2 Dose equations can be found in Appendix A.

3 MOE = POD (mg/kg/day) / Dose (mg/kg/day).

4 Combined MOE = NA

. A Ingestion of granules is considered episodic in nature; MOE was calculated using the acute dietary endpoint and PODPage 13 of 35



### 5.2.2 Residential Post

- application Exposure for Aquatic Use

2,4

- D can be used for aquatic weed control of surface and submerged weeds. According to the 2005 RED for 2,4

- D, the target concentration in the water column surrounding submer ged weeds is 2 to 4 ppm. Although many treatments are applied to aquatic areas where recreational swimming is not likely to occur, some subsurface treatments are made at recreational lakes. As a result, individuals can be exposed to 2,4

- D residues in w ater by entering these areas if they have been previously treated. A 24 hour swimming restriction was also added to the master label according to the RED. Of the possible post

- application exposures, swimming in treated water is considered by HED to be wo rse case and is used as a surrogate for all other possible post

application exposures . The extent of exposure during recreational swimming is assumed to be

short

- term in duration. Risks estimates were calculated for post

- application incidental oral inges tion while swimming in treated lakes or ponds. Inhalation exposure is expected to be negligible for swimmers ; therefore, a post

- application inhalation assessment was not conducted. Furthermore, the inhalation assessment for residential handlers is expected to be protective of potential post

- application exposure and risk.

Residential Post

- application Exposure Data and Assumptions for Aquatic Use A series of assumptions and exposure factors served as the basis for completing the residential

post

- appl ication risk assessment for the swimme rs scenario and can be found in Appendix A.

I nhalation exposure from swimming is expected to be negligible , especially in compared to ingestion

. Furthermore, 2,4

- D will exist primarily in anion form in the environmen t ; therefore

, significant volatilization from water surfaces is not anticipated because anions are not expected

to volatilize

.

The Agency considered residential post

- application exposure for different segments of the population. The lifestages selected fo r each post

- application scenario are based on an analysis provided as an Appendix in the 2012 Residential SOPs 7 

### . These lifestages are not the only lifestages that could be potentially exposed for these post

- application scenarios; however, the

assessment o f these lifestages is health protective for the exposures and risk estimates for any other potentially exposed lifestages.

The scenarios, routes of exposure and lifestages assessed include i ngestion of water during recreational swimming (both adults and children 3 < 6 years old).

The swimmer calculations have been updated from the previous assessment to reflect the revised body weights for adults and children. Also the water ingestion rates and the time spent in the water have been revised to correspond with the 2012 Residential S OPs. A body weight of 80 kg is used for assessing incidental oral ingestion for adults since the toxicity endpoint selected is not based on a developmental study where developmental and/or fetal effects were observed. The

level of concern for adults and ch ildren (3 to < 6 years old) for short

- term incidental oral exposures is MOEs < 100.

7 Available: http://www.epa.gov/pesticides/science/residential

- exposure

- sop.htmlPage 14 of 35



### Residential Post

- application Non

- Cancer Exposure and Risk Equations The equations and inputs are generally derived from SWIMODEL 3.0, developed by EPA as a screening tool to conduct exposure assessments of pesticides found in swimming pools and spas.

It uses well

- accepted screening exposure assessment equations to calculate the high end exposure for swimmers expressed as a mass

- based intake value (mg/event). The model fo cuses on potential chemical intakes only and does not take into account metabolism or excretion of the

chemical of concern. Detailed information and t he algorithms used to estimate residential post

application exposure from uses of 2,4

- D for aquatic appli cation are presented in Appendix A of

this document.

Summary of Residential Post

- application Exposure and Risk Estimates for Aquatic Use

Table 5.2. 5 presents the post

- application incidental oral ingestion MOE values calculated for

adults and children 3 to <6 years old after aquatic applications of 2,4

- D.

Post

- application risk estimates do not exceed HED’s level of concern for any of the scenarios

assessed.

Table 5.2. 2

. Residential Post

- application Non

- cancer Exposure and Risk Estimates for 2,4

- D (Swim mer Scenario)

Exposure Scenario Level of

Concern Maximum

Concentration

in Water 1
(mg/L) Exposure Dose

(mg/kg/day) 2 Short

- term

MOE 3

Ingestion of water,

Adult 100 4 0.0039 5

, 300

Ingestion of water,

Child 3<6 years 0.0306 690

1. Maximum concentration in water = 4 mg/L (4 ppm) based on maximum application rate for aquatic weed control: 10.8 lb ae/acre

- foot . It is possible that the concentration may exceed this value immediately after application before mixing. However it is conservative to assume exposure to this concentration for a short

- term duration (1 to 30 days) as well as considering the 24 hour swi mming restriction on the master label. 2. Exposure dose (mg/kg/day) = Refer to Appendix A. 3. MOE = NOAEL/Exposure dose. The level of concern for adults and children (3< 6 years old ) is MOEs < 100.



### 5 .3 Combined Residential Risk Estimates (Multiple Exposure Scenarios)

There are no combined residential exposure scenarios.

5

. 4 Residential Risk Estimates for Use in Aggregate Assessment

Table 5.4 reflects the residential risk estimates that are recommended for use in the agg regate assessment for 2,4

- D

. Inhalation exposures are not included in the aggregate assessment since effects from the inhalation endpoint are not systemic

Post

- application granular pesticide exposure following applications to lawns and turf are not included in the aggregate assessment as this exposure would not occur as a result of routine behavior and is considered an episodic event related to poisoning 

### The recommended residential exposure for use in the adult aggregate assessment reflects incidental oral exposure from post

- application exposure swimmer scenarioPage 15 of 35



### The recommended residential exposure for use in the children 1<2 years old aggregate

assessment reflects hand

- to

- mouth exposures from post

- application turf scenario (i.e.,

post

- application exposure to turf applications )Page 16 of 35

Table 5

. 4 .1. Recommendations for the Residential Exposures for the 2,4

- D Aggregate Assessment

. 1

Lifestage Residential Handler Residential Post

- application

Dose (mg/kg/day) 2 MOE 3 Dose (mg/kg/day) 4 MOE 5

Dermal Inhalation Total Dermal Inhalation Total Dermal Inhalation Oral Total Dermal Inhalation Oral Total

Short

- Term

Adult NA NA NA NA NA NA NA NA 0.0039 NA NA NA 5,300 NA

Child N /A NA NA 0.0315 NA NA NA 670 NA

1 Bolded risk estimates should contribute to the residential exposure portion of the aggregate assessment.

2 Residential Handler Dose = the highest handler dose for each applicable lifestage of all scenarios assessed from Table 5.1.1.

3 Residential Handler MOE = the lowest MOEs identified in Table 5.1.1.

4 Residential Post

- application Dose = the highest post

- application dose for each applicable lifestage of all scenarios assessed.

5 Residential Post

- application MOE = the MOEs associated with the highest doses identified.Page 17 of 35



### 5

. 5 Spray Drift

Off

- target movement of pesticides can occur via many types of pathways and it is go verned by a variety of factors. Sprays that are released and do not deposit in the application area end up off

target and can lead to exposures to those it may directly contact. They can also deposit on surfaces where contact with residues can eventually lead to indirect exposures ( e.g. , children playing on lawns where residues have dep osited next to treated fields). The potential risk estimates from these residues can be calculated using drift modeling coupled with methods employed for residential risk assessments for turf products.

The approach to be used for quantitatively incorporat ing spray drift into risk assessment is based on a premise of compliant applications which, by definition, should not result in direct exposures to individuals because of existing label language and other regulatory requirements intended to prevent them. 8 

### Direct exposures would include inhalation of the spray plume or being sprayed directly. Rather, the exposures addressed here are thought to occur indirectly through contact with impacted areas, such as residential lawns, when compliant applications are c onducted. Given this premise, exposures for children (1 to 2 years old) and adults who have contact with turf where residues are assumed to have deposited via spray drift thus resulting in an indirect

exposure are the focus of this analysis analogous to h ow exposures to turf products are

considered in risk assessment

.

Several 2,4

- D products have existing labels for use on turf, thus it was considered whether the risk assessment for that use may be considered protective of any type of exposure that would be associated with spray drift. If the maximum application rate on crops adjusted by the amount of

drift expected is less than or equal to existing turf application rates , the existing turf assessment is considered protective of spray drift exposure. Th e proposed maximum single application rate of 2,4

- D choline on herbicide

- tolerant corn and soybean is 1 lb ae/acre

. This is less than the registered application rate on turf of 1.5 lb ae/acre, which has been previously assessed and which was updated based on the revised SOPs for Residential Exposure Assessment (i.e., see above in Section 5.2) . Thus, even if 100% of the application rate on herbicide

- tolerant corn and soybean is deposited on an adjacent lawn

, calculated risk estimates from drift would not b e of concern. This again is because all existing registered use s on lawn s have been previously

assessed and no risks of concern were identified

.

T he registered residential uses on turf result in exposure greater than potential exposure from spray drift; therefore, no new residential assessment need s to be completed.

5.6 Volatilization

The potential exposure to bystanders from vapor phase 2,4

- D residues emitted from treated fields

has be en evaluated for the proposed use of 2,4

- D choline on herbicide

- tolerant corn and soybean

. Bystander exposure from 2,4

- D emitted from treated fields depends on two main factors: 1) the rate at which these chemicals come off a treated field (described as th e off

- gassing, emission or flux) and 2) how those vapors are dispersed in the air over and around the treated field.

8 This approach is consistent with the requirements of the EPA’s Worker Protection Standard

.Page 18 of 35



### Volatilization can occur during the application process or thereafter. It can result from aerosols evaporating during application, while d eposited sprays are still drying ( e.g. , possibly via co

distillation), or after as dried deposited residues volatilize. This assessment uses an analysis after sprays have dried.

This assessment employs approaches EPA has used previously to assess inhalat ion exposures to fumigant pesticides 9 

### and is also consistent with the recommendations of the December 2009 Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) 10 

### meeting

on the scientific issues associated with field volatiliz ation of conversional (semi

- volatile) pesticides

.

5.6.1 Flux Data

Flux data for 2,4

- D were submitted and reviewed by the Agency 11



### . The study measured the flux rates of 2,4

- D ethylhexyl ester (EHE), 2,4

- D dimethylamine salt (DMA salt) and the 2,4

- D

choline salt. 2,4

- D choline is the form proposed for use on herbicide

- tolerant corn and soybean. According to the registrant, 2,4

- D choline has a reduced potential for volatility. Treatments of the three forms were applied to tilled bare soil plo ts in F owler, IN and to mature soybeans approximately 30 cm high with 80% canopy in Farmland, IN. Treatments of the three forms plus a formulation with 2,4

- D choline plus glyphosate were also applied to growing soybeans approximately 12

- 15 cm high with 15 % canopy cover in Little Rock, AR and to cotton plants approximately 50 cm high with 40% canopy in Ty Ty, GA. Air samplers were placed in a wheel and spoke design at 5 and 15 meters from each treated field edge. Samplers were placed at a height of 30 cm in Fowler, at 50 cm in Farmland, at 15 cm in Little Rock, and at 50 cm in Ty Ty. 2,4

- D choline was applied at a ra te of 4 lb ae/acre in Farmland, Little Rock, and Ty Ty ; and at a

rate of 5 lb ae/acre in Fowler . Flux was calculated using the indirect meth od based on the study design. For this assessment, the data from the 2,4

- D choline applications only were used as this action specifically seeks registration for 2,4

- D choline product use in conjunction with the use of soybean and corn with resistance tra its

.

The flux profile s used for the assessment can be found in Appendix B. Flux rates are adjusted to the proposed application rate (i.e.

, 1 lb ae/acre) from the application rates in the flux study. This type of adjustment is done routinely for this type of data and analyses.

Quantitative analysis using flux rates derived from this study are described below

.

5.6. 2 Volatilization Modeling and Risk Assessment

Volatilization modeling for a single day was completed using Probabilistic Exposure and Risk model for FUMigants ( PERFUM). There are a variety of factors that potentially affect the

9 U.S. EPA 2004d. FIFRA Science Advisory Panel Meeting Minutes

- Fumigant Bystander Expos ure Model Review: Probabilistic Exposure and Risk Model for Fumigants (PERFUM) Using Iodomethane as a Case Study. Available at http://www.epa.gov/scipoly/sap/meetings/2004/august1/august2425minutes.pdf

10 U.S. EPA 2009

. FIFRA Science Advisory Panel Meeting Minutes

- Scientific Issues Associated with Field

Volatilization of Conventional Pesticides

. Available at http://www.epa.gov/scipoly/sap/meetings/2009/december/120309meetingminutes.pdf

11 MRID 48862902. Field Volatili ty of Different 2,4

- D Forms. June 15, 2012. Dow AgroSciences LLC.Page 19 of 35



### emission rates of 2,4

- D and subsequent offsite transport including: field condition (bare soil, growing or ma ture crop canopy), field parameters (soil type, moisture, etc.) , formulation type, meteorological conditions, and application scenario (rate, method ) . To the extent possible, based

on the limited information available and a lack of intentional statistica l design to quantitatively evaluate such factors, the impact of these variables was considered. Flux estimates from all

monitored trials , a number of field size s, and various meteorological data were used with

PERFUM to estimate risk based on the 2,4

- D fi eld volatility study summarized in Section 5.6.1 and Appendix B. The PERFUM modelling results are based on Bradenton, FL; Yakima, WA; Flint, MI; and Ventura, CA weather dataset s which have been used in the past for other volatilization analyses and represent a range of conditions including those which have consistently provided the highest risk estimates. The results of this analysis have been summarized for a 40, 80, and 120 acr e field using the flux data submitted for 2,4

- D choline and

each source of weather data. The short

- term residential inhalation endpoint was used in the volatilization assessment; it is a conservative assumption to compare the day 1 volatilization

exposure to a short

- term HEC. Furthermore, a 6

- hour exposure averaging period was used in the model; it is a conservative assumption to compare the 6 hour average exposure from the model to
the HEC calc ulated for 24 hours of exposure especially sin c e the 6 hour ex posure period used as the basis for the comparison represents the peak emissions period after application.

All of the files associated with the use of PERFUM in this assessment can be provided upon request. These files could be used to examine the deta iled input and output files for each permutation of the model completed for this analysis.

5.6 .3 Volatilization Risk Estimates

The field volatility study suggest s that volatilization of 2,4

- D from treated crops does occur and

could result in bystander exposure to vapor phase 2,4

- D . Results of PERFUM modeling, however, indicate that airborne concentrations, even at the edge of the treated fields, are not of

concern

. The maximum proposed application rate of 1 lb a.e ./A was assessed. There were no whole field and maximum field buffers estimated using PERFUM for any field size (i.e., risks were acceptable at all percentiles of exposure at the edge of a treated field)

.

Table 5.6.3 . Comparison o f Results For 2,4

- D Choline PERFUM Buffer Distributions Based On Flux Study a, b

Percentiles Field 1: Farmland, IN Meteorological Station Location Bradenton, FL Flint, MI Ventura, CA Yakima, WA

Max

Buffer c
(ft) Whole

Field

Buffer d

(ft) Max

Buffer c
(ft) Whole

Field

Buffer d

(ft) Max

Buffer c
(ft) Whole

Field

Buffer d

(ft) Max

Buffer c
(ft) Whole

Field

Buffer d

(ft) 40 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

80 A , 1 lb a.e /A

50 0 0 0 0 0 0 0 0Page 20 of 35

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0
120 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

Percentiles Field 2: Fowler , IN Meteorological Station Location Bradenton, FL Flint, MI Ventura, CA Yakima, WA

Max

Buffer c (ft) Whole

Field

Buffer d
(ft) Max

Buffer c (ft) Whole

Field

Buffer d
(ft) Max

Buffer c (ft) Whole

Field

Buffer d
(ft) Max

Buffer c (ft) Whole

Field

Buffer d
(ft) 40 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

80 A , 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0
120 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

Percentiles Field 3: Little Rock , AR Meteorological Station Location Bradenton, FL Flint, MI Ventura, CA Yakima, WA

Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) 40 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

80 A , 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0
120 A, 1 lb a.e /APage 21 of 35

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

Percentiles Field 4: Ty Ty , GA Meteorological Station Location Bradenton, FL Flint, MI Ventura, CA Yakima, WA

Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) Max

Buffer c (ft) Whole

Field

Buffer d

(ft) 40 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

80 A , 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0
120 A, 1 lb a.e /A

50 0 0 0 0 0 0 0 0

75 0 0 0 0 0 0 0 0

90 0 0 0 0 0 0 0 0

95 0 0 0 0 0 0 0 0

99 0 0 0 0 0 0 0 0

a. Short

- term Residential HEC 13000 μg/m 3 , UF = 300, target concentration 43.3 μg/m 3

b. Registrant study conducted using 2,4

- D Choline

c. Max buffers are the largest buffer estimated from any given direction away from the field. d. Whole field buffers are the average buffer estimated for an entire field (average for all directions)



### 6 .0 Occupational Exposure and Risk Estimates

6 .1 Occupational Handler Exposure/Risk Estimates

HED uses the term hand lers to describe those individuals who are involved in the pesticide application process. HED believes that there are distinct job functions or tasks related to applications and exposures can vary depending on the specifics of each task. Job requirements (amount of chemical used in each application), the kinds of equipment used, the target being treated, and the level of protection used by a handler can cause exposure levels to differ in a manner specific to each application event.

Based on the anticipated use patterns and current labeling, types of equipment and techniques that can potentially be used, occupational handler exposure is expected from the proposed uses. The quantitative exposure/risk assessment developed for occupatio nal handlers is based on the following scenarios: Mixing/Loading Liquid for Groundboom ApplicationPage 22 of 35



### Applying Spray by Groundboom Equipment

Occupational Handler Exposure Data and Assumptions

A series of assumptions and exposure factors served as the basis for completing the occupational handler risk assessments. Each assumption and factor is detailed below on an individual basis.

Application Rate : The proposed maximum single application rate on herbicide

- tolerant corn and soybean is 1 lb

ae/acre.

Unit Exposures: It is the policy of HED to use the best available data to assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemical

- specific data, include PHED 1.1, the AHETF database, the Outdoor Residential Exposure Task Force (ORETF) database, or other registrant

- submitted occupational exposure studies. Some of these data are proprietary (e.g., AHETF data), and subject to the data protection provisions of FIFRA.

The standard values recommended for use in predicting handler exposure that are used in this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table 12 

### ”, which, along with additional information on HED policy on use of surroga te data, including descriptions of the various sources, can be found at the Agency website 13



### .

Area Treated or Amount Handled : Area treated or amount handled includes: Groundboom equipment: 200 acres per day for high

- acreage field crops

Exposure Duration: HED classifies exposures from 1 to 30 days as short

- term and exposures 30 days to six months

as intermediate

- term. Exposure duration is determined by multiple factors , including the exposed population, the use site, the pest pressure t riggering the use of the pesticide, and the cultural practices surrounding that use site. For most agricultural uses, it is reasonable to believe that occupational handlers will not apply the same chemical every day for more than a one

month time frame; h owever, there may be a large agribusiness and/or commercial applicators who may apply a product over a period of weeks (e.g., completing multiple applications for multiple clients within a region).

For 2,4

- D, based on the proposed use, short

- and interm ediate

- term exposures are anticipated for the following reasons: (1) the product can be applied multiple times per year (2) the product can be applied to multiple application sites and (3) there may be a large agribusiness and/or commercial applicators wh o may apply a product over a period of weeks.

Mitigation/Personal Protective Equipment : Estimates of inhalation exposure are calculated for various levels of personal protective equipment (PPE). Results are presented for “baseline,” defined as a single layer of clothing consisting of a long sleeved shirt, long pants, shoes plus

12 Available: http://www.epa.gov/opp00001/science/handler

- exposure

- table.pdf

13 Available: http://www.epa.gov/pesticides/science/handler

- exposure

- data.htmlPage 23 of 35



### socks, no prote ctive gloves, and no respirator

. The 2,4

- D product labels direct mixers, loaders, applicators and other handlers to wear long

- sleeved shirt and long pants, shoes plus socks,

chemical

- resistant gloves, and protective eyewear; a chemical

- resistant apron is required when mixing or loading, c leaning up spills or equipment, or otherwise exposed to the concentrate

.

Occupational Handler Non

- Cancer Exposure and Risk Estimate Equations The algorithms used to estimate non

- cancer exposure and dose for occupational handlers can be found in Appendix A

.

Combining Exposures/ Risk Estimates : There is n o potential hazard via the dermal route f or 2,4

- D ; therefore, only occupational handler inhalation exposures are quantitatively assessed.

Summary of Occupational Handler Non

- Cancer Exposure and Risk Estimates Occupational handler risk estimates are not of concern (i.e., MOEs > LOC of 300) for all scenarios for use of 2,4

- D choline on herbicide

- tolerant corn and soybean. At baseline PPE (i.e., no respirator ), the occupational handler inhalation MOE is 4,900 for mixer/loaders and 3,200 for applicators using groundboom equipment.

Table 6.1.1. Occupational Handler Non

- Cancer Exposure a nd Risk Estimates for 2,4

- D

.

Exposure Scenario Crop or Target Inhalation Unit

Exposure ( μ g/lb ai) 1 Maximum

Application

Rate 2 Area

Treated Daily 3 Inhalation

Mitigation Level : No respirator Dose (mg/kg/day) 4 MOE 5

Mixer/Loader

Mixer/Loader, Liquid, Groundboom High Acreage Crop 0.219 1 lb ae/acre 200 acres 0.000548 4,900

Applicator

Applicator, Spray,

Groundboom High Acreage

Crop 0.34 1 lb ae/acre 200 acres 0.00085 3,200

1 Based on the “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” ( March 2013 ); Level of mitigation: Baseline.

2 Based on proposed labels

. 3 Exposure Science Advisory Council Policy #9.1.

4 Inhalation Dose = Dermal Unit Exposure ( μ g/lb ai) × Conversion Factor (0.001 mg/ μ g) × Application Rate (lb ai/acre or gal) × Area Treated or Amount Handled Daily (A or gal/day) ÷ BW (kg).

5 Inhalation MOE = Inhalation NOAEL (mg/kg/day) ÷ Inhalation Dose (mg/kg/day).



### 6

. 2 Occupational Post

- application Exposure/ Risk Estimates

HED uses the term post

- application to describe exposures that occur when individuals are present in an environment that has been previously treated with a pesticide (also referred to as re

entry exposure). Such exposures may occur when workers enter previously treated areas to perform job functions, including activities related to crop production, such as scouting for pests or harvesting. Post

- applicati on exposure levels vary over time and depend o n such things as the type of activity, the nature of the crop or target that was treated, the type of pesticide application, and the chemical’s degradation properties. In addition, the timing of pesticide appl ications, relative to harvest activities, can greatly reduce the potential for post

- application exposure.Page 24 of 35



### 6

. 2 .1 Occupational Post

- application Inhalation Exposure/Risk Estimates

Based on the Agency's current practices, a quantitative occupational post

- application inhalation exposure assessment was not performed for 2,4

- D at this time primarily because of the low acute inhalation toxicity (Toxicity Categ ory III) and vapor pressure ( 1.4 x 10 - 7 

### mm Hg at 25°C for 2,4

- D acid ) . However, there are multi ple potential sources of post

- application inhalation exposure to individuals performing post

- application activities in previously treated fields. These potential sources include volatilization of pesticides and resuspension of dusts and/or particulates th at contain pesticides. The Agency is in the process of evaluating available post

- application inhalation exposure data generated by the ARTF and may, as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to in corporate occupational post

application inhalation exposure into the Agency's risk assessments. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative occupational

post

- application inhalation exposure assessme nt for 2,4

- D

.

Although a quantitative occupational post

- application inhalation exposure assessment was not performed, an inhalation exposure assessment was performed for occupational/commercial handlers. Handler exposure resulting from application of pes ticides outdoors is anticipated to result in higher exposure than post

- application exposure. Therefore, it is expected that these handler inhalation exposure estimates would be protective of most occupational post

- application inhalation exposure scenarios

. Furthermore, a quantitative volatilization inhalation exposure assessment was assessed for bystanders in Section 5.6 and indicates no risk of concern for bystanders.

6

. 2 .2 Occupational Post

- application Dermal Exposure/Risk Estimates

Occupational Post

- application Dermal Exposure

There is n o potential hazard via the dermal route f or 2,4

- D ; therefore, a quantitative occupational

post

- application dermal risk assessment was not completed.

Restricted Entry Interval

The REI specified on the proposed label is based on the acute toxicity of 2,4

- D. 2,4

- D is classified as Toxicity Category III via the dermal route

, Toxicity Category IV for skin irritation potential , and Toxicity Category I for eye irritation . It is not a s kin sensitizer. Under 40 CFR 156.208 (c) (2) (iii), ai’s classified as Acute Toxicity Category I for acute dermal, eye i rritation or primary skin irrit ation are assigned a 48

- hour REI. Therefore, the [156 subpart K] Worker

Protection Statement interim RE I of 48 hours is adequate to protect agricultural workers from

post

- application exposures to 2,4

- D

.Page 25 of 35



### Appendix A. Summary of Occupational and Residential Non

- cancer Algorithms

Residential Non

- cancer Handler Algorithms

Dermal and Inhalation Handler Exposure Algorithm Daily dermal and inhalation exposure (mg/day) for residential pesticide handlers, for a given

formulation

- application method combination, is estimated by multiplying the formulation

application method

- specific unit exposure by an estimate of the amount of active ingredient handled in a day, using the equation below:

E = UE * AR * A

where:

E = exposure (mg/day); UE = unit exposure (mg/lb ai); AR = application rate (e.g., lb ai/ft 2 

### , lb ai/gal); and

A = area treated or amount handled (e.g., ft 2 

### /day, gal/day).

Residential Non

- cancer Post

- application Algorithms

Turf/Physical Activities on Turf

Post

- application Dermal Exposure Algorithm

– Physical Activities on Turf

* The dermal exposure is necessary to address the hand

- to

- mou th exposure scenario

Exposure resulting from contacting previously treated turf while performing physical activities is calculated as shown below. Residential post

- application exposure assessment must include calculation of exposure on the day of applica tion. Therefore, though an assessment can present exposures for any day “t” following the application, it must include “day 0” exposure.

E = TTRt * CF1 * TC * ET

where:

E = exposure (mg/day); TTRt = turf transferable residue on day t (μg/cm 2 

### );

CF1 = weight unit conversion factor (0.001 mg/μg); TC = transfer coefficient (cm 2 

### /hr); and ET = exposure time (hr/day).

If chemical

- specific TTR data are available, then surface residues from the day of application should be used (assume that individuals could be exposed to residues immediately after application). However, if data are not available, then TTR t 

### can be calculated using the following

formula:Page 26 of 35 

### TTR t 

### = AR * F * (1

- FD) t 

### * CF2 * CF3

where:

TTRt = turf transferable residue on day t (μg/cm 2 

### ); AR = application rate (lbs ai/ft 2 

### or lb ai/acre); F = fraction of ai as transferable residue following application (unitless); FD = fraction of residue that dissipates daily (unitless);

t = post

- application day on which exposure is being assessed;

CF2 = we ight unit conversion factor (4.54 x 10 8 

### μg/lb); and CF3 = area unit conversion factor (1.08 x 10 - 3 

### ft 2 

### / cm 2 

### or 2.47 x 10 - 8 

### acre/cm 2 

### ).

Dermal absorbed doses are calculated as:

where:

D = dose (mg/kg

- day);

E = exposure (mg/day);

AF = absorption factor (dermal); and

BW = body weight (kg).

Table A

- 1 : Turf (Physical Activities)

-- Inputs for Residential Post

- application Dermal Exposure

Algorithm Notation Exposure Factor (units) Point Estimate(s)

AR Application rate (mass active ingredient per unit area) 1.5 lb ae/acre

F Fraction of AR as TTR

following application (if

chemical

- specific data is unavailable) L/WP/WDG 0.01

Granules 0.002

F D Daily residue dissipation

(if chemical

- specific data is unavailable) (fraction) L/WP/WDG 0.1

Granules 0.1

TC Transfer

Coefficient (cm 2 /hr) L/WP/WDG Adults 180,000
Children 1 < 2 years old 49,000

Granules Adults 200,000

Children 1 < 2 years old 54,000

ET Exposure Time

(hours per day) Adults 1.5 Children 1 < 2 years old 1.5

BW Body Weight (kg) Adults 80

Children 1 < 2 years old 11 L/WP/WDG = Liquids/Wettable Powders/Water

- dispersible Granules



### Post

- application Hand

- to

- Mouth Exposure Algorithm

– Physical Activities on TurfPage 27 of 35



### Exposure from hand

- to

- mouth activity is calculated as follows (based on the algorithm utilized in

the SHEDS

- Multimedia model ):

E = [HR * ( F

M 

### * SA H 

### ) * (ET * N_Replen) * (1

- (1

- SE ) (Freq_HtM/N

- Replen) 

### )]

where:

E = exposure (mg/day);

HR = hand residue loading (mg/cm 2 

### ); FM = fraction hand surface area mouthed / event (fraction/event); SAH = typical surface area of one hand (cm 2 

### ); ET = exposure time (hr/day); N_Replen = number of replenishment intervals per hour (intervals/hour);

SE = saliva extraction fa ctor (i.e., mouthing removal efficiency); and Freq_HtM = number of hand

- to

- mouth contacts events per hour (events/hour).

and

where:

HR = hand residue loading (mg/cm 2 

### );

Fai hands 

### = fraction ai on hands compared to total surface residue from dermal transfer coefficient study (unitless); DE = dermal exposure (mg); and

SA H 

### = typical surface area of one hand (cm 2 

### ).

Dose, normalized to body weight, is calculated as:

wher e:
D = dose (mg/kg

- day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A

- 2 : Turf (Physical Activities)

– Inputs for Residential Post

- application Hand

- to

- Mouth Exposure Algorithm

Notation Exposure Factor (units) Point Estimate(s)

Fai hands Fraction of ai on hands

from dermal transfer coefficient study (unitless) Liquid formulations 0.06

Granular formulations 0.027Page 28 of 35

Table A

- 2 : Turf (Physical Activities)

– Inputs for Residential Post

- application Hand

- to

- Mouth Exposure Algorithm

Notation Exposure Factor (units) Point Estimate(s)

DE Dermal exposure (mg) Calculated

SA H Typical surface area of one hand (cm 2 ), children 1 < 2 years old 150

AR Application rate

(mass active ingredient per unit area) 1.5 lb ae/acre

HR Residue available on the hands (mg/cm 2 ) Calculated via (DE * Fai hands )/SA H

F M Fraction hand surface area mouthed (fraction/event) 0.127

N_Replen Replenishment intervals per hour (intervals/hr) 4

ET Exposure time (hrs/day) 1.5

SE Saliva extraction factor (unitless) 0.48

Freq_HtM Hand

- to

- mouth events per hour (events/hr) 13.9

BW Body Weight

(kg) Children 1 < 2 years old 11



### Post

- application Object

- to

- Mouth Exposure Algorithm

– Physical Activities on Turf Exposure from object

- to

- mouth activity is calculated as follows (based on the algorithm utilized

in SHEDS

- Multimedia):

E = [OR* CF1 * SAM O 

### * (ET * N_Replen) * (1

- (1

- SE O 

### ) (Freq_OtM/N_Replen) 

### )]

where:

E = exposure (mg/day); OR = chemical residue loading on the object on day “t” (ug/cm 2 

### ); CF1 = weight unit conversion factor (0.001 mg/μg);

SAM O 

### = area of the object surface that is mouthed (cm 2 

### /event); ET = exposure time (hr/day); N_Replen = number of replenishment intervals per hour (intervals/hour);

SE O 

### = saliva extraction factor (i.e., mouthing removal efficiency); and Freq_OtM = number of object

- to

- mouth contact events per hour (events/hour).

and

OR = AR * F O 

### * CF2 * CF3

where:

OR = chemical residue loading on the object (μg/cm 2 

### ); AR = application rate (lbs ai/ft 2 

### or lb ai/acre);

F O 

### = fraction of residue available on the object (unitless);Page 29 of 35



### CF2 = weight unit conversion factor (4.54 x 10 8 

### μg/lb); and

CF3 = area unit conversion fac tor (1.08 x 10 - 3 

### ft 2 

### /cm 2 

### or 2.47 x 10 - 8 

### acre/cm 2 

### ).

Dose, normalized to body weight, is calculated as:

where:

D = dose (mg/kg

- day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A

- 3 : Turf (Physical Activities)

– Inputs for Residential Post

- application Object

- to

- Mouth Exposure
Algorithm

Notation Exposure Factor (units) Point Estimate(s)

AR Application rate (to turf)

(mass active ingredient per unit area) 1.5 lb ae/acre

F O Fraction of AR as OR following application 1 0.01

SAM O Surface area of object mouthed (cm 2 /event) 10

N_Replen Replenishment intervals per hour (intervals/hour) 4

SE O Saliva extraction factor (fraction) 0.48

ET Exposure time (hours per day) 1.5

Freq_OtM Object

- to

- mouth events per hour (events/hr) 8.8

BW Body Weight (kg) Children 1 < 2 years old 11

1 This SOP assumes that all of the residue on the turf could be transferred to the object (e.g., object residue is equal to turf transferable residue).



### Post

- application Incidental Soil Ingestion Exposure Algorithm

– Physical Activities on Turf Exposure from incidental soil ingestion is calculated as follows:

E = SRt * SIgR * CF1

where: E = exposure (mg/day);

SRt = soil residue on day "t" (μg/g); SIgR = ingestion rate of soil (mg/day); and CF1 = weight unit conversion factor (1 x 10 - 6 

### g/μg).

and

SRt = AR * FS * (1

- F D 

### ) t 

### * CF2 * CF3 * CF4

where:Page 30 of 35



### SR t 

### = soil residue on day "t" (μg/g); AR = application rate (lbs ai/ft 2 

### or lb ai/acre); FS = fraction of ai available in uppermost cm of soil (fraction/cm);

F D 

### = fraction of residue that dissipates daily (unitless); T = post

- application day on which exposure is being assessed; CF2 = weight uni t conversion factor (4.54 x 10 8 

### μg/lb); CF3 = area unit conversion factor (1.08 x 10 - 3 

### ft 2 

### /cm 2 

### or 2.47 x 10 - 8 

### acre/cm 2 

### ); and CF4 = soil volume to weight unit conversion factor (0.67 cm 3 

### /g soil).

Dose, normalized to body weight, are calculated as:

where :
D = dose (mg/kg

- day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A

- 4 : Turf (Physical Activities)

– Inputs for Residential Post

- application Incidental Soil Ingestion Exposure
Algorithm

Notation Exposure Factor (units) Point Estimate(s)

AR Application rate

(mass active ingredient per unit area) 1.5 lb ae/acre

FS Fraction of AR available in uppermost 1 cm of soil (unitless) 1

F D Daily residue dissipation (fraction) 0.1

SIgR Soil ingestion rate (mg/day) 50

BW Body weight (kg) Children 1 < 2 years old 11



### Post

- application Episodic Granular Ingestion Exposure Algorithm

– Physical Activities on Turf Exposure from incidental ingestion of pesticide pellets or granules is calculated as follows:

E = GIgR* FD * CF1

where: E = exposure (mg/day); GIgR = ingestion rate of dry pesticide formulation (g/day); FD = fraction of ai in dry formulation (unitless); and CF1 = weight unit conversion factor (1,000 mg/g).

Dose, normalized to body weight, are calculated as:Page 31 of 35



### where :
D = dose (mg/kg

- day);

E = exposure (mg/day); and

BW = body weight (kg).

Table A

- 5: Turf (Physical Activities)

– Inputs for Residential Post

- application Episodic Granular Ingestion Exposure
Algorithm

Notation Exposure Factor (units) Point Estimate(s)

F D Fraction of active ingredient in dry formulation 3%

AR Application rate (lbs/A or lbs/1,000 ft 2 ) 1.5 lb ae/acre

GIgR Granule ingestion rate per day (g/day) 1 0.05

BW Body Weight (kg) Children 1 < 2 years old 11

1 See discussion below on how this value is adjusted.



### Post

- application granular pesticide exposure following applications to lawns and turf would not occur as a result of routine behavior and is considered an episodic event related to poisoning.

The default ingestion rate for dry pesticide formulations (e.g., pellets and granules) is 0.3 gram/day for children 1 < 2 years old . It is assumed that if 150 pounds of product were to be applied to a 1⁄2 acre lawn, the amount of product per square foot would be approximately 3 g/ft 2



### and a child would consume one

- tenth of the product available in a square foot. According to the 2012 Residential SOP, if product

- specific information is available, the granular ingestion rate may be adjusted to reflect the amount of product applied on a per area basis if it is less or more than 150 pounds to a 1⁄2 acre lawn. For instance, if 50 pounds of product is meant to treat a 1⁄2 acre lawn, then the ingestion rate should be reduced by a third to 0.1 grams/day. As the maximum application rate for 2,4

- D on lawns is 1.5 lb ae/acre, and the maximum percent of active ingredient in dry formulation is 3%, the maximum amount of product to treat an acre is 50 pounds; or a maximum of 25 pounds of product to treat a half

- acre. Therefore, the point estimate for gr anular ingestion rate (GIgR) has been adjusted to 0.05 grams/day.

Swimming

The algorithms and their inputs and assumptions used to estimate residential post

- application exposure and dose for the proposed/ registered use of 2,4

- D for aquatic application a re outlined

below.

There is the potential for post

- application incidental oral (water ingestion) exposures to 2,4

- D residues in water following trea tment to control aquatic weeds. Exposures during recreational swimming are assumed to be short

- term in d uration. The equations and inputs are generally derived from SWIMODEL 3.0, developed by EPA as a screening tool to conduct exposure assessments of pesticides found in swimming pools and spas. It uses well

- accepted screening exposure assessment equations to calculate the high end exposure for swimmers expressed as a

mass

- based intake value (mg/event). The model focuses on potential chemical intakes only and

does not take into account metabolism or excretion of the chemical o f concern. DetailedPage 32 of 35



### information and the downloadable executable file are available at http://www.epa.gov/oppad001/swimodel.htm , however, some of the inputs and parameters have been updated and are out lined below. The equations as provided in the SWIMODEL User's Manual (version 3.0) were used in a spreadsheet format to estimate the exposures.

Ingestion of Water while Swimming

The equation below taken from SWIMODEL 3.0 is used to calculate post applic ation ingestion exposures while swimming. Exposure from incidental ingestion of treated water is calculated as

follows:

Where:

E = exposure (mg/day),

C

w 

### = chemical concentration in water (mg/L), IgR = ingestion rate of water (L/hr),

ET = exposure time (hrs/day).

Dose, normalized to body weight, is calculated as:

w here :
D = dose (mg/kg

- day);

E = exposure (mg/day);

BW = body weight (kg).

Table A

- 6 : Swimming

– Inputs for Residential Post

- application Incidental Oral Exposure Algorithm

Notation Exposure Factor (units) Point Estimate(s)

Cw Chemical concentration in water (mg/L) 4 ppm

IgR Water ingestion rates (L/hr)

are based on the 2011 Exposure Factors Handbook (USEPA, 2011), Table 3

- 5. Adult 0.021

Children 3 < 6 years old 0.049

ET Exposure time (hours per

day) for recreational

activities in water is based on the 2011 Exposure Factors Handbook (USEPA, 2011) data on average time spent in a pool, river, or lake (Tables

16

- 19 and 16

- 20). Adult 3.7

Children 3 < 6 years old 3

BW Body Weight (kg) based on

the 2011 Exposure Factors Handbook (USEPA, 2011). Adults 80

Children 3 < 6 years old 19Page 33 of 35



### Occupational Non

- cancer Handler Algorithms

Potential daily exposures for occupational handlers are calculated using the following formulas:

where:

E = e xposure (mg ai/day),

UE = u nit e xposure (μ g ai/ lb ai),

AR = m aximum application rate according to proposed label (lb ai A or lb ai/gal ), and

A = a rea treated or amount handled (e.g., A/day, gal/day)

.

The daily doses are calculated using the following formula:

where:

ADD = average daily dose a bsorbed in a given scenario (mg ai/ kg / day),

E = e xposure (mg ai/day),

AF = absorption fa ctor (dermal and/or inhalation), and

BW = body weight (kg)

.

Margin of Exposure: Non

- cancer risk estimates for each application handler scenario are calculated using a Margin of Exposure (MOE), which is a ratio of the toxicological endpoint to the daily dose of concern. T he daily dermal and inhalation dose received by occupational

handlers a re compared to the appropriate POD ( i.e.

, NOAEL) to assess the risk to occupational handlers for each exposure route. All MOE values a re calculated using the following formula:

where:

MOE = m argin of e xposure: value used by HED to represent risk estimates (unitless),

POD = p oint of d eparture (mg/kg/day)

, and

ADD = average daily dose absorbed in a given scenario (mg ai/kg/day)

.Page 34 of 35



### Appendix B. Flux Rates and Flux Profiles

Flux Rates for 2,4

- D Choline

Period Hours After Treatment 2,4

- D Choline

Flux (μg/ m 2

- s) Rate Adj. Flux (μg/ m 2

- s)

Field 1

- Farmland, IN

1 3 2.2E

- 2 5.5E

- 3

2 9 2.9E

- 4 7.25E

- 5

3 15 8.3E

- 6 2.08E

- 6

4 21 5.8E

- 6 1.45E

- 6

5 34 5.1E

- 4 1.28E

- 4

6 45 4.8E

- 5 1.2E

- 5

7 58 5.9E

- 4 1.48E

- 4

8 69 6.0E

- 5 1.5E

- 5

Field 2

- Fowler, IN

1 5 7.7E

- 2 1.53E

- 2

2 11 9.3E

- 4 1.85E

- 4

3 17 6.2E

- 4 1.23E

- 4

4 23 6.9E

- 3 1.37E

- 3

5 34 2.6E4 5.16E

- 5

6 47 1.6E

- 6 3.17E

- 7

7 59 5.2E

- 6 1.03E

- 6

8 70 3.3E

- 6 6.55E

- 7

Field 3

- Little Rock, AR

1 5 7.5E

- 2 1.88E

- 2

2 10 2.1E

- 3 5.25E

- 4

3 16 3.3E

- 4 8.25E

- 5

4 23 1.3E

- 4 3.25E

- 5

5 36 6.1E

- 3 1.53E

- 3

6 47 2.1E

- 4 5.25E

- 5

7 60 2.0E

- 4 5.0E

- 5

8 71 1.2E

- 4 3.0E

- 5

Field 4

- Ty Ty, GA

1 4 1.17E

- 2 1.48E

- 3

2 10 2.83E

- 3 3.58E

- 4

3 16 1.25E

- 3 1.58E

- 4

4 22 3.16E

- 4 4.0E

- 5

5 36 4.84E

- 4 6.13E

- 5

6 47 1.1E

- 4 1.39E

- 5

7 60 2.94E

- 4 3.72E

- 5

8 71 9.87E

- 5 1.25E

- 5Page 35 of 35



### Flux Profile Used in PERFUM Analysis

Time (hr) 2,4

- D choline (only) a μg/m 2 /sec Field 1: Farmland,

IN Field 2: Fowler, IN Field 3: Little Rock,

AR Field 4: Ty Ty, GA

Crop: Soybean Tilled Bare Soil Crop: Soybean Crop: Cotton Day 1

- App. Start

Time 10:00 Day 1

- App. Start

Time 9:00 Day 1

- App. Start

Time 7:00 Day 1

- App. Start

Time 9:00

1 1.45E

- 06 1.23E

- 04 3.25E

- 05 2.90E

- 05

2 1.45E

- 06 1.37E

- 03 3.25E

- 05 2.90E

- 05

3 1.45E

- 06 1.37E

- 03 3.25E

- 05 2.90E

- 05

4 1.45E

- 06 1.37E

- 03 3.25E

- 05 2.90E

- 05

5 1.45E

- 06 1.37E

- 03 3.25E

- 05 2.90E

- 05

6 1.45E

- 06 1.37E

- 03 1.53E

- 03 2.90E

- 05

7 1.28E

- 04 1.37E

- 03 1.88E

- 02 1.38E

- 04

8 1.28E

- 04 5.16E

- 05 1.88E

- 02 1.38E

- 04

9 1.28E

- 04 1.53E

- 02 1.88E

- 02 2.63E

- 03

10 5.50E

- 03 1.53E

- 02 1.88E

- 02 2.63E

- 03

11 5.50E

- 03 1.53E

- 02 1.88E

- 02 2.63E

- 03

12 5.50E

- 03 1.53E

- 02 5.25E

- 04 2.63E

- 03

13 7.25E

- 05 1.53E

- 02 5.25E

- 04 2.53E

- 04

14 7.25E

- 05 1.85E

- 04 5.25E

- 04 2.53E

- 04

15 7.25E

- 05 1.85E

- 04 5.25E

- 04 2.53E

- 04

16 7.25E

- 05 1.85E

- 04 5.25E

- 04 2.53E

- 04

17 7.25E

- 05 1.85E

- 04 8.25E

- 05 2.53E

- 04

18 7.25E

- 05 1.85E

- 04 8.25E

- 05 2.53E

- 04

19 2.08E

- 06 1.85E

- 04 8.25E

- 05 7.78E

- 05

20 2.08E

- 06 1.23E

- 04 8.25E

- 05 7.78E

- 05

21 2.08E

- 06 1.23E

- 04 8.25E

- 05 7.78E

- 05

22 2.08E

- 06 1.23E

- 04 8.25E

- 05 7.78E

- 05

23 2.08E

- 06 1.23E

- 04 3.25E

- 05 7.78E

- 05

24 2.08E

- 06 1.23E

- 04 3.25E

- 05 7.78E

- 05

a. Flux profile uses rate adjusted flux (i.e., scaled down to the proposed maximum single broadcast application rate
of 1 lb a.e./A ). Period 1 flux corresponds to start time in the flux profile.