OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460



### PC Codes: 119031 DP Barcode: D428419 Parent DP Barcode: 424558 Chemical: Penoxsulam

August 28 , 2015

MEMORANDUM

SUBJECT: Penoxsulam Drinking water exposure concentrations for th e proposed new uses on pome fruit group 11

- 10 (plus olive and pomegranate)
, stone fruit group (12

- 12) , conversion of nut tree group 12 to tree nut group 14

- 12, and group expansion from grapes to include small fruit vine climbing subgroup ( 13

- 07F ) and updat ed assessment for drinking water exposure for the other uses

.

TO: Banza Djapao, Reviewer Heather Garvie
, P M 24 Herbicide Branch Registration Division 7505P

Linda Arrington, Branch Chief Bonnie Adler, CRM Jill Bloom, Team Leader Risk Management and Implementation Branch V Pesticide Re

- Evaluation Branch 7508P

Christina Swartz, Branch Chief Elizabeth Holman, Risk Assessor Risk Assessment Branch 2 Health Effects Division (7509P)

FROM: James K. Wolf , Ph.D., Environmental Scientist Environmental Risk Branch 3

THRU: Dana Spatz, Branch Chief Environmental Risk Branch 3 Environmental Fate and Effects Division [EFED] (7507P)

PEER James A. Hetrick , Ph.D., Senior Advisor REVIEW: Rosanna Louie

- Juzwiak, RAPL Environmental Risk Branch 3 Environmental Fate and Effects Division [EFED] (7507P)

### 2 The Environmental Fate and Effects Division (EFED) has prepared a drinking water assessm ent for consideration in t he tolerance for the requested new uses and crop group expansions for Pindar ® 

### GT Herbicide which contains two active ingredients (a.i.). This assessment only considers penoxsulam, as oxyfluorfen would be considered in a separate a ssessment

. This document provides estimated drinking water concentrations (EDWCs) f or penoxsulam TTR (total toxic residues) in surface and ground water sources fo r the proposed new use s of penoxsulam . This assessment also provides an updated assessment for recommended EDWCs for all registered uses for human health dietary risk
assessment.

The IR4 has requested amending t he existing Pindar ® 

### GT Herbicide; (EPA Reg. # 62719

- 611 and Penoxsulam Technical EPA Reg. # 62719

- 499 ) . They propose to add grapevines and a non

- dormant application (California only)
, to expand the bearing and non

- bearing tree nut groups for dormant and

non

- dormant tree nuts , non

- bearing citrus trees, and add preemergence and postemergence control of annual weeds on olive and pomegranate, po me fruit (crop group 11

- 10 ) and stone fruit (crop group 12

- 12 )

. The new uses and crop group expansions and application rates are summarized in Appendix A. Table A1

. The single application rates for the new uses range from 0.010 to 0.031 lb a.i./A

, and the maximum annual rate would be 0.047 lb a.i./A/season. Minimum reapplication ( i

. e ., sequential) interval for the new

uses is 30 days.

O ther registered uses we re re

- evaluated here

. The turf use has the highest single and yearly application
rate (0.0 6 0 lb a. i./A and 0.090 lb a.i./A , respectively ) and was included in the re

- evaluation. Rice and direct treatment of water areas were considered in prior assessments for the highest registered uses ( i.e.
, rice or direct aquatic applications)

. Reapplication interval s for existing uses ranged for 21 to 30 days.

Recommended Drinking Water Concentrations

The estimated drinking water concentrations (EDWCs) for p enoxsulam residues of concern ( ROCs ) , or penoxsulam TTR, are based upon model estimates using the maximum a pplication rate and number of applications.

Maximum EDWCs for the proposed new uses and crop group expansion and existing uses are summarized in Table 1 . T he EDWCs for penoxsulam TTR for all uses except direct application to water and rice were estimate d for groundwater [with PRZM

- GW or SCI

- GROW] and for surface water [SWCC or FIRST] ( Table 1 ). The range of EDWCs for the proposed new uses for the scenarios evaluated and existing uses [ e.g., ornamental lawns turf] are given in Table 4 (surface water) and Table 5 (groundwater).

The recommended EDWCs ( i.e. , the highest value) for penoxsulam would be for the direct aquatic use where the exposure concentrations could be as high as the maximum treatment concentration of 150 μg/L (penoxsulam) for as long as 6 0 days

. While generally lower than the 150 ppb, estimates for g roundwater are predicted to be higher compared to surface water (USEPA, 2006 1 

### , USEPA, 2008 2 

### , and USEPA, 2010 3 

### )

.

1 USEPA, 2006. Shanaman, L. Tier 1 Drinking Water Assessment for the New Use Registration on Turf and Aquatic Vegetation of

Penoxsulam, and Six Degradation Products Identified to Be of Toxicological Concern (D325468).

2 USEPA, 2008. Wolf, J.K. Penoxsulam (New Use) Tier 1 Drinking water exposure concentrations for the proposed new uses

almond hulls, grapes, tree nuts (crop group 14), and pistachios, and tolerance ass essments. (Action Type Section, new use, R180 and reduce risk designation request) (D355676).

3 USEPA, 2010. Wolf, J.K. Penoxsulam (New Use) Tier 1 Drinking water exposure concentrations for the proposed new uses on

non

- bearing trees, conifers, eucalyptus, and non

- cropland. (D273443).

### 3 Estimated Drinking Water Concentrations

Surface Water Exposure

The penoxsula m TTR EDWCs for the proposed new uses and crop group expansion are less than previous assessments for surface water

. Surface water EDWCs from an earlier assessment (D325468), using the FIRST model for the turf use rates (D325468) were 9.4 μg/L and 0.92 μg/ L for acute and chronic exposure, respectively, which are higher than the estimates with SWCC model ( Table 1 ). It should be noted that the turf use (D325468) was based upon higher application rates (0.0 6 0 to 0.090 lb a.i./A) than considered in this new use assessment (e.g., 0.047 lb a.i./A) ( Appendix A. Table A1 ). The direct aquatic use results in the highest EDWCs, where the exposure concentrations could be as high as the maximum treatment concentration of 150 μg/L (penoxsulam) for as long as 60 days

.

Gro undwater Exposure

For groundwater, the PRZM

- GW model’s NC Coastal Plain scenario resulted in highest daily and post breakthrough average concentrations ; at the maximum rates
, EDWCs for the new uses were 25.9 and 17.5 μg/L, respectively. Ornamental lawns a nd turf have the highest application rates (0.06 lb a.i./A single application and 0.09 lb a.i./A annual rate) ; m aximum groundwater penoxsulam TTR EDWCs estimated with PRZM

- GW are 46.3 μg/L and 31.3 μg/L, for highest daily and post

- breakthrough concentratio ns, respectively.

Table 1. Summary of Maximum Penoxsulam TTR EDWCs for New Uses and Crop Group Expansions and Currently Registered Uses.

Model Previous Assessments [Uses and Rates] New Use [D428419, D424558] All Uses [Updated] Surface Water μg/L FI RST [D325468] Peak 9.40 a

- - Annual Average 0.92 a

- - Long Term Average 0.92 a

- - SWCC [This assessment] 1

- yr in 10

- yr Peak 0.95 b 1.54 1.54 1

- yr in 10

- yr Annual Average 0. 30 b 0.23 0. 30 30

- Year Ave. 0. 11 b 0.11 0. 11 Rice (Interim Rice Model) [D32 5468] 45

- 45 Water Treatment c [D325468]

Direct Application to Water 150

- 150 Groundwater PRZM

- GW [This assessment] Highest Daily Concentration 46.3 d 25.9 46.3 Post

- Breakthrough Average 31.3 d 17.5 31.3 SCI

- GROW [D325468] 23.3

- -

a Turf rate with FIRST (2 apps 0.06 lb a.i./A and 0.03 lb a.i./A ; 30 day interval )
b Turf rate with SWCC (Table 4).

### 4 c Application of penoxsulam to aquatic sites can be injected under the surface of water to achieve a target concentration not t o exceed 150 ppb, ground sprayed to exposed sediment after drawdown, or applied either aerially or by ground spray to floating or emerged aquatic vegetation

. d Turf rate with PRZM

- GW (Table 5)



### Use s and Label Information

Pindar GT (EPA Reg. No. 62719

- 611) contains two active ingredients (a.i.) penoxsulam (0.85% a.i.) and oxyfluorfen (40.31% a.i.). Pindar GT contains 0.083 pounds of penoxsulam per gallon. Penoxsulam is a systemic herbicide that can be used for postemergence burn

- down and preemergence residual control of weeds. A single rainfall event or sprinkler irrigation of 0.5 inches or more, or flood irrigation within 21 days after application, is necessary to activate penoxsulam. The proposed single application rate ranges b etween 0.01 0 to 0.0 31 lb a.i./A with a maximum seasonal amount of 0.047 lb a.i./A ( Table 2 ). Reapplication intervals when specified on the label range from 21 to 30 days.

The current turf uses (ornamental lawns, sod farms) for products containing penoxsulam have the highest

use rates (excludi ng aquatic/water uses) with a maximum single rate of about 0.060 lb a.i./A with a seasonal maximum rate of about 0.090 lb a.i./A

. Other uses such as citrus, tree nuts, and grapes have lower application rates ( Appendix C Table 1 )

. Aerial application of pen oxsulam (Pindar GT) is not permitted o n the label (Pindar ® 

### GT EPA Reg. No. 62719

- 611 or the Supplemental Labeling (EPA Reg No. 62719

- 611) MSTR/Ame n d ment /10

- 17

- 14 ). However, a erial application is included on s ome of the other labels , primarily rice and aqua tic uses ( e.g., EPA Reg. No. 62719

- 546, 62719

- 610 )

.

For the in

- water treatment, the label specifies that t he concentration of any single application or sum of all applications must not exceed 150 ppb per annual growth cycle. Retreat the water to maintain a sufficient concentration for a minimum of 60 days or until satisfactory weed control is achieved (EPA Reg. No. 67690

- 71).

Use limitations is by season (harvest to harvest) for EPA Reg. No. 62719

- 11 , the number of seasons were not specified ; thus , it was assumed that there is only 1 cropping season per year. Similar assumptions were made f or the other registrations where the total maximum application rate is not given on a per year basis

. Application rates, method and timing by rate and EPA Reg. No. are s ummarized from BEAD LUIS report (09/09/14) in Appendix C . Table 1

.

Drinking Water Residues of Concern (ROC)

The Health Effects Division (HED) determined that penoxsulam (synonyms DE

- 638, XDE

- 638, and XR

- 638) and six (of 11) degradation products were of toxicological concern (USEPA, 2004a) for drinking water . The penoxsulam degradation products identified in the fate studies are: BSTCA, 2

- amino TCA, 5

- OH

penoxsulam , SFA, sulfonamide, and 5,8

- di OH. A combined residue, or total toxic residue (TTR), approa ch was used in the penoxsulam drinking water assessment.

Persistence and Transformation

Penoxsulam is expected to be moderately persistent in the aerobic terrestrial environments, and less persistent in anaerobic environments. The degradation products t end to be more persistent than the parent compound. Penoxsulam is expected to dissipate rapidly in clear shallow waters through aqueous

### 5 photolysis. Thus, in turbid, shaded or acidic waters, photolysis of penoxsulam is expected to be slower, and other degra dation mechanisms are expected to predominate. Laboratory data indicates that the four photolytic half

- lives reported for penoxsulam in water range from 1.5 to 3.1 days between pH 7 and pH 8, and 14 days at pH 5.8. A reported pK a 

### value of 5.1 suggests that pH may have an effect upon the photolytic half

- life. In aqueous environments, penoxsulam is stable to hydrolysis at pH 5, 7 and 9.

Eleven major degradation products were previously identified for penoxsulam (BSTCA, 2

- amino

- TCA, 5

- OH

- penoxsulam, SFA, s ulfonamide, 5,8

- di

- OH

- penoxsulam, BSA, 2

- amino

- TP, TPSA, BSTCA methyl, and 5

- OH 2 amino TP). Data are not available to fully characterize these degradates and their re spective degradation pathways. The six degradation products occurred in the [aerobic soil , aerobic and anaerobic aquatic] metabolism studies. Only BSTCA (soil photolysis, aqueous photolysis) and 2

- Amino TCA (aqueous photolysis) were identified as photodegradates. The environmental fate and transport characteristics of penoxsulam and several de gradates were described in more detail in previous assessments (D288160, D325783, D355671).

Transport and Mobility

Penoxsulam is expected to be mobile in terrestrial environments, not binding strongly to soil. Penoxsulam has low volatility. Submitted m obility data for three penoxsulam degradation products (BSTCA, 5

- OH

penoxsulam, and BST) indicate environmental mobility roughly equivalent to or slightly greater than the parent compound. The soil to water partition coefficients (K d 

### ) derived from the seve nteen soils and one sediment studied ranged from 0.12 to 10.67 mL/g. Calculated K oc 

### s ranged from 12 to 1,141 mL/g oc 

### . The K oc 

### values for the sediment were 1118 and 1141 mL/g oc 

### (K d 

### s = 1.38 and 1.41 mL/g). There are no data regarding the mobility of the remai ning transformation products nor the combined parent/degradate residues. The lowest average K oc 

### was 45.3 mL/g oc 

### for 5

- 0H

- penoxsulam was used as an input for modeling as it is one of the ROC and it appears to be one of the more persistent degradates. A sum mary of the mobility data can be found in Appendix B , T able B 2

. The exposure from the total toxic residues ( penoxsulam TTR) were estimated by using the half

- life estimated from the decline of the penoxsulam total residues with time (D325468) and the mobil ity of the most mobile degradation product (MRID #s 45830801, 45830802). The penoxsulam TTR are more persistent than the parent compound. The environmental data for use as model inputs are also depicted in Table 3

.

Modeling Inputs

The estimated drinki ng water concentrations (EDWCs) for all uses (except rice and aquatic areas) were conducted with the PRZM

- GW 4 

### (version 1.07) model for groundwater and the SWCC 5 

### (version 1.106) for surface water) model, and current guidelines for model inputs. Also, becaus e the label (EPA Reg. No. 62719

- 611) requires nozzles for “coarse” spray, the default spray drift fraction for coarse spray is used rather than stand default value for very fine to fine spray. The maximum number of applications, maximum application rates, and the minimum reapplication intervals ( Table 1 ; e.g., 2 applications @ 0.031 and 0.016 lb a.i./A, 30 day reapplication interval) was used.

4 http://www.epa.gov/oppefed1/models/water/index.htm#przm_gw

5 http:// www.epa.gov/oppefed1/models/water/index.htm#swcc

### 6 A summary of the current fate and transport properties of penoxsulam appears in Table 3 , below. The model input va lues [previous value] from the prior assessment is also presented in Table 3

.

Table 3 . Model I nput parameters for Penoxsulam TTR

.

Input Variable Input Value [Previous Assessment] Environmental Fate Data MRID

Molecular Weight (penoxsulam) 483.4 g/mole

- - -- Solubility @ pH 7 (penoxsulam) 410 mg/L

-- -- Vapor Pressure (penoxsulam) 7.16 x 10

- 16 torr

- - Hydrolysis (penoxsulam) Stable

- 45830721 Photolysis (Aqueous) t 1⁄2 (penoxsulam) (upper bound on mean) 2.9 day [4.3] a 40°N 1.5, 1.5, 3.1 days 45834801

TTR Aerobic Soil t 1⁄2 6
, 7 (upper bound on mean) 0 days

- Stable [467] a (See Table 8) >365 days 45830724

TTR Anaerobic Soil & Sediment

- - 45830725 TTR Anaerobic Aquatic t 1⁄2 20 ,2 1 system) 2 soils 2 soils + sediment (upper bound on mean) 168 days [88.3 days] a 847 days 70.8, 132 days (soil)

70.8, 132 soils; 950 days ( s ediment) 45830725

TTR Aerobic Aquatic t 1⁄2 20 ,2 1 (system) 120.3 days [36.6 days] a 136, 84.8, 84.9, 96 days 45830726

K d (5

- OH

- penoxsulam) 0.54 mL/g [0.13] a n = 16 (average) [lowest non

- sand] 4583 0802

K oc (5

- OH

- penoxsulam) 45.25 mL/g oc [13] a n = 16 (average) [lowest non

- sand] 45830802

Spray drift Fraction (Aerial Coarse Drop size) 0.068 [0.05] a High Boom EFED Guidance (Ground Coarse Drop size) 0.017 [0.01] a High Boom Application Efficiency Aerial Ground 0.95 0.99 EFED Guida n ce

t 1⁄2 is the upper bound of mean t ot al toxic residues (TTR) half

- life estimated by PestDF in Appendix A , Table A 1

. TTR Residues of Concern (ROC) includes penoxsulam parent plus degradation products BSTCA, 2

- amino TCA, 5

- OH

- peno x sulam
,

SFA, sulfonamide, and 5,8

- di OH.

a [] value used in previous assessments.



### Surface Water

Eleven SWCC standard scenarios were selected to be representative of the proposed new uses and crop group expansions for pome fruit ( NC Apple, OR Apple, PA Apple ), stone fruit (GA Peach), tree nut (CA Almond, GA Pecans, OR Filberts), grapes (CA grape, NY Grape) , and non

- bearing Citrus (FL Citrus). Two initial application dates were assumed, 0 and 20 days after emergence (crop emergence , scenario specific), with a 30 day reapplication interval.

Two standard turf (FL Turf and PA Turf) scenarios were selected to represent the highest use rates for penoxsulam. The initial application selected were 230 and 20 days after crop emergence with a 28 day reapplication interval.

6 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/NAFTA_Degradation_Kinetics_Equations.htm

7 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/archive2015/ftt_sop_using_nafta_guida nce.pdf

### 7 The surface water EDWCs were influenced by the scenario (soil and weather differences) and the date of the initial application

. Peak concentration for the new uses range from 0.17 to 1.54 μg/L; annual means ranged from 0. 07 to 0.23 μg/L; 30 year means ranged from 0.029 to 0.114 μg/L. Differences in EDWCs between sites were more pronounced than the difference s in EDWCs due to the da te of the initial application. For turf scenarios, being the highest application rates 

### , EDWCs range from 0. 46 to 0.95 μg/L; annual means ranged from 0. 17 to 0. 30 μg/L; 30 year means ranged from 0. 08 to 0. 11 μg/L . As in previous assessments, surface water concentrations were less than those for groundwater.

T able 4

. Surface Water EDWCs Penoxsula m TTR in μg/L resulting from the maximum proposed penoxsulam use rate s a on number of crops (scenarios) and 2 first application dates and turf (maximum registered rate) using the SWCC.

SWCC Scenario a ( First A pplications 0 DAE ) b Peak Annual Mean 30 Year Mea n 1 yr in 10 yr (μg/L) (μg/L) CA almond W irrigation 0.44 0.1 5 0.068 CA fruit W irrigation 0.42 0 .18 0.051 CA grapes W irrigation 0.17 0.071 0.029 FL Citrus 1.38 0

. 23 0.100 GA Pecans 0.75 0.1 2 0.051 GA Peaches 0.28 0.08 0 0.03 5 NC apple 0.45 0.1 3 0.05 3 NY Grapes 0.4 3 0 .15 0.101 OR apple 0.3 0 0. 10 0.039 OR filberts 0.3 7 0.1 2 0.047 PA apple 0.43 0.1 4 0.054 (First Applications 20 DAE) b CA almond W irrigation 0.34 0.12 0.045 CA fruit W irrigation 0.30 0.12 0.039 CA grapes W irrigation 0.17 0.075 0.029 FL Citrus 1.20 0.20 0.096 GA Peach 0.23 0.072 0.027 GA Pecan 1.54 0.22 0.079 NC apple 0.51 0.13 0.063 NY Grapes 0.55 0.20 0.114 OR a pple 0.31 0.11 0.039 OR filberts 0.39 0.12 0.061 PA apple 0.34 0.12 0.045 Maximum Label Rates (Ornamental Sod Farm Ornamental Lawns and Turf) c FL Turf [230 DAE) 0.95 0.30 0.11 PA Turf [20 DAE) 0.46 0. 17 0. 08

a SWCC estimated EDWCs ( 2 applications @ 0.031 and 0.016 lb a.i./A with 30 day reapplication interval
b DAE

– Day after emergence (crop)

– defined by scenario

c SWCC estimated EDWCs (2 application @ 0.0603 and 0.0301 lb a.i./A with 28 day reapplication interval.



### The six standar d PRZM

- GW scenarios 8 

### used in the groundwater simulations were developed to be representative of known vulnerable sites

— shallow, unconfined aquifers under an agricultural field with leaching prone soil and adequate precipitation and/or irrigation. Output va lues represent pesticide concentrations that may be observed in private drinking water wells resulting from the use of groundwater vulnerable to pesticide contamination. Ground water EDWCS estimated with PRZM

- GW for the six scenarios are summarized in Table 5

.

8 Florida Central Ridge, Florida Potato, Wisconsin Central Sands, Georgia Southern Coastal Plain, North Carolina

Easter n Coastal Plain, and Delmarva Peninsula.

### 8 For groundwater, the EDWCs the ranged 7.0 to 46.3 μg/L depending upon scenario and application rate. Post

- breakthrough averages for groundwater ranged from 5.5 to 31.3 μg/L depending upon scenario and application rate ( Table 5 ). Example outputs are given in Appendix D

.

Table 5 . PRZM

- GW Estimated Drinking Water Concentrations (EDWCs) in Groundwater for (Penoxsulam TTR).

Scenario a First Application [Days After Emergence] Highest Daily Value Post

- breakthrough Average Average Breakthrough Time/Through puts (day ) μg/L Days Maximum Rate for New use (2 applications 0.031 lb a.i./A and 0.016 lb a.i./A with 30 day reapplication interval) Delmarva 20 18.3 13.5 1608/6.8 FL Citrus 20 15.4 12.5 1171/9.4 FL Potato 20 12.7 9.6 1531/7.2 GA Coastal Plain 20 7.0 5.5 1962/5.6 NC Coastal Plain 20 25.9 17.5 2371/4.6 W I Central Sands 20 17.1 14.9 2977/3.7 Maximum Rate A ll uses (2 applications 0.0603 lb a.i./A and 0.0301 lb a.i./A with 30 day reapplication interval) Delmarva 20 35.2 25.9 1608/6.8 FL Citrus 20 29.7 24,0 1171/9.4 FL Potato 20 24.5 18.5 1531/7.2 GA Coast al Plain 20 13.4 10.7 1963/5.6 NC Coast al Plain 20 46.3 31.3 2371/4.6 W I Central Sand s 20 33.0 28.8 2977/3/7

a SWCC Scenarios
b DAE

– Day after emergence (crop)

– defined by scenario



### The p ersistence of a pesticide (i.e., half

- life ; Appendix B Table B 1 ) has a major influence on PRZM

- GW estimates, the 90 percent upper bound DT 50 

### (391.2 days) and DT 90 

### (1,239 days) were also used with NC Coastal Plain scenario (highest estimated groundwater con centrations). The highest daily values were 32.2 and 41.1 μg/L for the DT 50 

### and DT 90 

### half

- life values, respectively. The highest concentration after breakthrough were 22.6 and 28.2 μg/L for the DT 50 

### and DT 90 

### half

- life values, respectively.

### 9 Appendix A. P roposed Application Rates and for New Uses and Crop Group Expansion for Penoxsulam.

The r egistrant propose s to add grapevines and a non

- dormant application (California only) and to expand the bearing and non

- bearing tree nut groups for dormant 9 

### and non

- do rmant 10 

### tree nuts, non

- bearing citrus trees 11 

### , and add supplement labeling for Pindar ® 

### GT Herbicide for preemergence and postemergence control of annual weeds on olive and pomegranate, pome fruit (crop group 11

- 10) 12 

### and stone fruit (crop group 12

- 12). 13 

### The p roposed used rates are summarized in Appendix A. Table A1

.

Appendix A. Table A1 . Proposed new uses and crop group expansion [in bold] requested by IR4 and the Registrant for Penoxsulam for Pindar GT a

Summary Application Rate Pint/A (lb a.i./A) Max single Pint/A (lb a.i./A) Combined Pre and Post Emergence Max single season b Pint/A (lb a.i./A) Dormant Application: Bearing and Non

- Bearing Tree Nuts and Grapevines (Small Vine Climbing Fruit 13

- 07F) Pre

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031) 4.5 (0.047) 1

- 3 months 1.5

– 2 (0.016

- 0.021) 2 (0.021) 1

- 6 months 2

– 3 (0.021

- 0.031) 3 (0.031) Post

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031) Non

- Dormant Application Tree Nuts (For Arizona and California only) Pre

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031) 3 ( 0.031) Post

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031) 4

- inch/4 leaf stage 0.05

- 1 (0.005

- 0.010) 1 (0.010) Clean

- up 2

– 3 (0.021

- 0.031) 3 (0.031) Grapevines Non

- Dormant Application (Small Vine Climbing Fruit 13

- 07F) (For California Only) Pre

- emergence 0.25

– 1 (0.003

- .010) 1 (0.010) 1 non

- dormant Post

- emergence 0.25

– 1 (0.003

- .010) 1 (0.010) Per season 4 (0.042) (dormant + non

- dormant) Non

- Bearing Citrus Trees c Pre

- emergence 4.5 (0.047) 2

- 3 months 1.5 (0.016) 1.5 (0.016) 4

- 6 months 3 (0.031) 3 (0.031) Winter dormant

- March 15 1.5

– 3 (0.016

- 0.031) 3 (0.031) Sequential appl. 1.5 (0.016) 1.5 (0.016) Pre & Post

- emergence Annual Weeds in Olive and Pomegranate d Pre & Post

- emergence Annual Weeds in Pome Fruit, 11

- 10 d

9 Bearing and Non

- Bearing Tree Nuts (African nut

- tree; almond; beechnut; Brazil nut; Br azilian pine; bunya; bur oak; butternut; Cajou nut; candlenut; cashew; chestnut; chinquapin; coconut; coquito nut; dika nut; ginkgo; Guiana chestnut; hazelnut (filber t); heartnut; hickory nut; Japanese horse

- chestnut; macadamia nut; mongongo nut; monkey

- po t; monkey puzzle nut; Okari nut; Pachira nut; peach palm nut; pecan; pequi; Pili nut; pine nut; pistachio; Sapucaia nut; tropical almond; walnut, black; walnu t, English; yellowhorn; cultivars, varieties, and/or hybrids of these) and Grapevines

– Dormant Ap plication. Non

- bearing tree nuts and grapevines are those which will not bear a crop within one year.

10 Bearing and Non

- Bearing Tree Nuts (African nut

- tree; almond; beechnut; Brazil nut; Brazilian pine; bunya; bur oak; butternut; Cajou nut; candlenut; cash ew; chestnut; chinquapin; coconut; coquito nut; dika nut; ginkgo; Guiana chestnut; hazelnut (filbert); heartnut; hickory nut; Japanese horse chestnut; macadamia nut; mongongo nut; monkey

- pot; monkey puzzle nut; Okari nut; Pachira nut; peach palm nut; pequi ; Pili nut; pine nut; Sapucaia nut; tropical almond; yellowhorn; cultivars, varieties, and/or hybrids of these)

– Non

- Dormant Application (For Use in Arizona and California Only)

11 Non

- Bearing Citrus Trees: Calamondin, chironja, citrus citron, grapefruit, k umquat, lemon, lime, mandarin, pummelo, satsuma mandarin, sour orange, sweet orange, tangelo, tangerine, tangor.

12 Pome Fruit : Apple; azarole; crabapple; loquat; mayhaw; medlar; pear; pear, Asian; quince; quince, Chinese; quince, Japanese; tejocote; culti vars, varieties, and/or hybrids of these.

13 Stone Fruit : Apricot; apricot, Japanese; capulin; cherry, black; cherry, Nanking; cherry, sweet; cherry, tart; Jujube, Chinese; nectarine; peach; plum; plum, American; plum, beach; plum, Canada; plum, cherry; pl um, Chickasaw; plum, Damson; plum, Japanese; plum, Klamath; plum, prune; plumcot; sloe; cultivars, varieties, and/or hybrids of these.

### 10 Summary Application Rate Pint/A (lb a.i./A) Max single Pint/A (lb a.i./A) Combined Pre and Post Emergence Max single season b Pint/A (lb a.i./A) Pre & Post

- emergence Annual Weeds in Stone Fruit, 12

- 12 d Pre

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031) 4.5 (0.047) Post

- emergence 1.5

– 3 (0.016

- 0.031) 3 (0.031)

a EPA Reg. No. 62719

- 611 (amend 10

- 17

- 14) Pindar GT 0.85 % a.i. (Penoxsulam); 0.083 lb penoxsulam./gallon; 0.000648 lb a.i./fl oz.
b Combined preemergence and postemergence for single growing season (harvest to harvest)

c Non

- bearing citrus trees will not bear a crop within one year after treatment with Pindar.
d Supplemental Label For use o nly in AZ, CA, MI, OH, OR, NC, NM, NY, PA, SC, and WA

### 11 Appendix B

. Reassessment of Environmental Fate Data for Modeling Inputs for Drinking Water Assessments

No additional environmental fate studies have been considered for this asse s sment. However, t he model inputs parameters in Table 3 were reevaluated to conform to current modeling input guidance.

For exposure modeling, EFED models use the simplistic approach, assuming all pesticide transformation processes follow the first

- order exponential func tion even though pesticide transformation in soil and aquatic systems often involve multiple intertwined processes and do not follow a single exponential decline pattern. PestDF was developed as a tool for calculating and selecting the representative half

- life value based on the NAFTA guidance

. 14
, 15 

### The tool considers three transformation models SFO, double first

- order in parallel (DFOP), and indeterminate order rate equation (IORE) and a set criteria for selecting parameters. SFO is the simplest of the three models while DFOP is the most complex.

The penoxsulam TTR “half

- lives” were recalculated for modeling inputs using PestDF R software 16 

### is a compatible script (PestDF version 3.1.2 and xxDeg 08.13) following NAFTA 17 

### guidance. Several other practices have c hanged per EFED modeling input parameters guidance 18 

### in addition to the “half

- lives” [as determined by PestDF]. The average K d 

### or K oc 

### is now recommended instead of the lowest non

- sand value. The “half

- lives” calculated and chosen following the NAFTA kineti cs guidances generally resulted in longer values (2 to 4 times) than previously used for modeling. The exception is for aerobic soil metabolism where half

- lives were not observed in the study (e.g., penoxsulam TTR residue exceeded 50% at the end of the 365 day study). Half

- lives estimated by PestDF (t R IORE 

### ) were in excess of 7,990 days for penoxsulam TTR

. In terrestrial environments, or when sunlight is readily available to degrade penoxsulam, it is expected to be moderately persistent, dissipating throu gh soil photolysis and biotic degradation. Penoxsulam has photolytic half

- lives of 19 (flooded soil) and 109 days, on the two soils studied at pH 6. Aerobic soil metabolism was studied in three US soils. The resulting half

- lives for parent penoxsulam calc ulated by linear regression on the log transformed data (SFO) were 62.5, 55.3, and 118 days for soils fro m AR, CA, and ND, respectively. For modeling PestDF recommended the T R IORE 

### half

- life for parent penoxsulam range between 17 and 142 days (Appendix A T able A1) and the 1 st 

### order model (SFO), half

- lives ranged from 11 to 64 days ( Appendix B. Table B 1 ).

For the aerobic soil metabolism studies, PestDF recommended the t R IORE 

### model for penoxsulam TTR for modeling with “half

- life” values of greater than 7
, 9 00 days which far longer than 365 day study duration ( Appendix B. Table B 1 ), therefore, penoxsulam TTR was assumed to be stable for modeling inputs (input value = 0 days) .

Aerobic aquatic metabolism was studied in six soil/water test systems (includin g 2 soils from Japan). The four total system half

- lives calculated through linear regression of log transformed data ranged from 12 to 38 days. The two Japanese soils 19 

### were not included as they may not be representative of soils in the U.S. ( i.e. , volcani c soil). Anaerobic aquatic metabolism was studied in three soil/water test systems. The three total system half

- lives calculated through linear regression of log transformed data were 5 days, 7

14 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/NAFTA_Degradation_Kinetics_Equations.htm

15 http://www.epa .gov/oppefed1/ecorisk_ders/degradation_kinetics/archive2015/ftt_sop_using_nafta_guidance.pdf

16 http://www.r

- project.org/ ) R Statistical Foundation for Statistical Computing

17 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/ftt_sop_using_nafta_guidance.pdf

18 http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

19 MRID 458307

- 26 Aerobic Aquatic Metabolism

. Japanese soils V olcanic soil (t 1⁄2 = 29 days) none volcanic soil (t 1⁄2 = 29.5 days)

### 12 days, and 11 days. Half

- lives of were recalculated using Pe stDF the residues of concern (TTR) for model inputs. 20
, 21 

### The resulting half

- lives for penoxsulam TTR (the residues of concern) obtain by PestDF for modeling are summarized in Appendix B, Table B1

. The resulting half

- lives for penoxsulam TTR (the residues of concern) obtain by PESTDF for modeling are summarized in Appendix B , Table B 1

. Appendix B
, Table B 1 . Aerobic Soil Metabolism Half

- lives for Penoxsulam Parent and Penoxsulam TTR Estimated with PestDF

Soil PestDF Recommendation DT 50 

### [SFO] DT 90 

### [SFO] MRI D (days) Penoxsulam Parent Arkansas t R IORE 

### = 18 11.2 37.3 45830724 California t R IORE 

### = 17.4 11.9 39.7 North Dakota Slow t 1⁄2 

### = 142 64 213 90% upper

- bound on mean 

### 104.24 48.07 160.01 Penoxsulam TTR Arkansas t R IORE 

### = 1.54 x 10 7 

### 421 1
, 298 458307 24 California t R IORE 

### = 7.99 x 10 3 

### 178 590 North Dakota t R IORE 

### = 4.41 x 10 6 

### 341 1
, 131
90 % upper
- bound on mean 

### 391.187 1
, 238.99

Note: Upon review of the DER for the aerobic soil metabolism study (MRID 45830724), it was noted that the half

- live s calculated for the Arkansas (0 to 179 days) and California (0 to 270 days) did not include the final sampling date (i.e., day 365). Therefore, the half

- lives presented in the DER were recalculated which resulted in longer half

- lives. The first order li near regression half

- life for Arkansas is 33.8 days (0 to 179 days) and 62.6 days (0 to 365 days) and for California 43.4 days (0 to 270 days) and 55.3 days (0 to 365 days). The North Dakota soil used all data (0 to 365 days).

The current model input guid ance indicates that the average (K oc 

### or K d 

### ) be used for both groundwater and surface water. Previous guidance indicated that the lowest non

- sand K oc 

### or K d 

### be used.

Appendix B , Table B 2. Average K oc for penoxsulam and three degradation products in differe nt soils and sediment

. Soil Additional Information Penoxsulam BSTCA BST 5

- 0H

- penoxsulam

Location/texture/ID Koc (mL/g oc ) US NC s [M538] 76 46 34 34 US AR sil [M557] 40 156 61 34

Japan l [M558] Volcanic 22

- - - Japan scl [M559] Non

- Volcanic 40

- - -

Japan l [M560] Volcanic 305

- - - Japan l [M561] Non

- Volcanic 195

- - - US CA cl [M562] 20 25 18 18 US ND l [M563] 21

- 21 38

20 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinet ics/NAFTA_Degradation_Kinetics_Equations.htm

21 http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/archive2015/ftt_sop_using_nafta_guidance.pdf

### 13 Soil Additional Information Penoxsulam BSTCA BST 5

- 0H

- penoxsulam

Italy sicl [M570] 253 444 85 144 France sicl [M571] 66 74 48 42 UK scl [M572] 13 5 5 18 Italy sl [M573] 46

- 71 3 4 Mean (all) 91.42 125.00 42.88 45.25 Mean (US) 39.25 75.67 33.50 31.00 Sediment (U.S) 1,129.5

- - - MRID 4580801 45830802 45830802 45830802 M558 and M559 upland soils M560 and M561 rice

### 14 Appendix C Table 1 Penoxsulam Use Rate Summary based upon BEAD a 

### Report (09/09/14).

EPA Reg. No. Use Single Max Appl. Rate [ lb a.i./A ] Max Seasonal or CC App [ lb a.i./A ] Application Method Application Timing

62719

- 611 Agr/uncultivated

areas Almond Beech Nut Brazil Nut Butternut Cashew Chestnut Citrus Filbert ( Hazelnut) Grape Grape Hickory Nut Macadamia Nut Pecan Pistachio Non Agr. Uncultivated/soils Walnut (English Black Nut) 0.0478 0.0319

-

-

-

-

-

-

- 0.0106 0.0319

-

- 0.0319

- 0.0478 0.0319 - 0.0478

NS 0.0478 0.0106 0.0478

-

- 0.0478

- NS 0.0478 Broadca st Directed Spray

-

-

-

-

-

-

- Directed Spray Directed Spray

-

- Directed Spray

- Broadcast Direct Spray Weed pre and post emergence Dormant weed pre and post emergence Dormant

Dormant Non

- bearing

62719

- 612 Conifer (seed orchard) Eucalyptus Fruit tre e (All or unspecified Grapes Grapes Non Agr. Uncultivated/soils Tree Nuts 0.0312

-

-

-

- 0.0312 0.0415

-

-

-

- 0.0415 Directed Spray

-

-

Broadcast Directed Spray Broadcast/Directed Spray Weed preemergence Dormant Weed preemergence Dormant Weed preemerge nce Weed preemergence Dormant/Weed
preemergence

62719

- 546 Aquatic areas/water Aquatic areas/water Aquatic areas/water Ornamental Lawns/turf Ornamental Lawns/turf Ornamental Lawns/turf

Ornamental Sod Farm (turf) 0.0879 0.1758 0.4097 0.0603 0.0603 0.0603

0.0603 NS

-

- 0.0904 0.0904 0.0904

0.0904 Spray Spray Water Treatment (subsurface) Broadcast Low volume Spray (concentrate) Spot Treatment Broadcast Low volume Spray (concentrate) Spot Treatment Weed postemergence

62719

- 603 Conifer (seed orchard) Euc alyptus Fruit tree (All or unspecified Grapes Non Agr. Uncultivated/soils

Tree Nuts 0.0314

- 0.0314

0.0314 0.0628 0.0314 0.0628

- 0.0471

0.0471 NS 0.0471 Broadcast Directed Spray

-

Broadcast

Broadcast Weed postemergence Dormant/Weed preemergence/Weed postemergence

Dormant/weed pre & post emergence

### 15 EPA Reg. No. Use Single Max Appl. Rate [ lb a.i./A ] Max Seasonal or CC App [ lb a.i./A ] Application Method Application Timing

2217

- 995 Non Agr. Uncultivated/soils

- Ornamental Lawns/turf Ornamental Sod Farm (turf) 0.02

0.02 0.02 0.02 0.0401

0.0401 0.0401 0.0401 Broadcast

Spot treatment Broadcast/Spot Treatment Weed Postemerge nce

2217

- 974 Non Agr. Uncultivated/soils Ornamental Lawns/turf

Ornamental Sod Farm (turf) 0.035 0.035 0.035 0.035 0.070 0.070 0.070 0.070 Broadcast Spot treatment Broadcast/Spot Treatment Broadcast/Spot Treatment Weed Postemergence

62719

- 589 Ornamental Lawns/turf Ornamental Sod Farm (turf) Residential Lawns 0.0175

0.0175 0.035

0.035 Broadcast

Broadcast

62719

- 590 Ornamental Lawns/turf Ornamental Sod Farm (turf) Residential Lawns 0.0175

0.0175 0.035

0.035 Broadcast

Broadcast Weed postemergence

62 719

- 543 62719

- 548 62719

- 549 62719

- 550 62719

- 585 62719

- 588 62719

- 606 Ornamental Lawns/turf Ornamental Sod Farm (turf) Residential Lawns 0.063

-

-

-

-

-

- 0.091

-

-

-

-

-

- Broadcast

-

-

-

-

-

- Weed postemergence

62719

- 547 Ornamental Lawns/turf Ornamental Sod Farm (turf) 0.0587

-

-

- 0.0899

-

-

- Broadcast

- Low volume Spray (concentrate) Spot Treatment Weed postemergence

62719

- 610

62719

- 500

62719

- 616 62719

- 607 Rice 0.0448

- 0.044

- 0.0415 0.042 0.0448

- 0.044

- 0.0415 0.042 Broadcast Flooded Treatme nt Broadcast Water Treatment (subsurface) Broadcast Broadcast Postemergence

Weed postemergence At permanent flood Foliar Foliar Postemergence

62719

- 501 62719503 Rice 0.0444 0.0444 Water Treatment (subsurface) Weed postemergence

62719

- 514 Rice 0.044 0. 044 Spray Weed postemergence 62719

- 546 67690

- 47 67690

- 71 Direct aquatic use

– aquatic weeds Max conc. 150 ug/L Water application Aerial application Maintain for minimum of 60 days

a Penoxsulam (119031) Label Use Report Package in Support of Registration Review (09/11/14)

### 16 Appendix D. Sample Output from the SWCC and PRZM

- GW Models

Summary of Water Modeling of penoxsulam+degradates and the USEPA Standard Reservoir Estimated Environmental Concentrations for penoxsulam+degradates are presented in Table 1 fo r the USEPA standard reservoir with the GAPecansSTD field scenario. A graphical presentation of the year

- to

- year peaks is presented in Figure 1. These values were generated with the Surface Water Concentration Calculator (SWCC Version 1.106). Critical inpu t values for the model are summarized in Tables 2 and 3. This model estimates that about 0.89% of penoxsulam+degradates applied to the field eventually reaches the water body. The main mechanism of transport from the field to the water body is by runoff (9 3.9% of the total transport), followed by spray drift (5.83%) and erosion (0.22%). In the water body, pesticide dissipates with an effective water column half

- life of 38.2 days. (This value does not include dissipation by transport to the benthic region; i t includes only processes that result in removal of pesticide from the complete system.) The main source of dissipation in the water column is washout (effective average half

life = 57.9 days) followed by metabolism (165.7 days), photolysis (351.5 days), a nd volatilization (5.166555E+14 days). In the benthic region, pesticide dissipation is negligible (1166.6 days). The main source of dissipation in the benthic region is metabolism (effective average half

- life = 1166.6 days). Most of the pesticide in the be nthic region (83%) is sorbed to sediment rather than in the pore water.

Table 1. Estimated Environmental Concentrations (ppb) for penoxsulam+degradates.

Peak (1

- in

- 10 yr) 1.54

4

- day Avg (1

- in

- 10 yr) 1.48

21

- day Avg (1

- in

- 10 yr) 1.27

60

- day Avg (1

- in

- 10 yr) 0.921

365

- day Avg (1

- in

- 10 yr) 0.224

Entire Simulation Mean 0.788E

- 01

Table 2. Summary of Model Inputs for penoxsulam+degradates.

Scenario GAPecansSTD Cropped Area Fraction 1.0 Koc (ml/g) 45.25

Water Half

- Life (days) @ 25 °C 120.3

Benthic Half

- Life (days) @ 25 °C 847 Photolysis Half

- Life (days) @ 40 °Lat 2.9 Hydrolysis Half

- Life (days) 0

Soil Half

- Life (days) @ 25 °C 0

Foliar Half

- Life (days) 0

Molecular Wt 483.4 Vapor Pressure (torr) 7.16e

- 16 Solubility (mg/l) 410

### 17 Table 3. Applicati on Schedule for penoxsulam+degradates.

Date (Days Since Emergence) Type Amount (kg/ha) Eff. Drift

20 Ground 0.0347 0.99 0.017
50 Ground 0.0179 0.99 0.017

Figure 1. Yearly Peak Concentrations

Groundwater Analysis for penoxsulam + degradates of conce rn (TTR) and the NC Eastern Coastal Plain

- Norfolk Loamy Sand

- Cotton Scenario
Estimated groundwater concentrations and breakthrough times for penoxsulam + degradates of concern (TTR) are presented in Table 1 for the NC Eastern Coastal Plain

- Norfolk lo amy sand

- Cotton groundwater scenario. A graphical presentation of the daily concentrations in the aquifer is presented in Figure 1. These values were generated with the PRZM

- GW (Version 1.07). Critical input values for the model are summarized in Tables 2 and 3.

Table 1. Groundwater Results for penoxsulam + degradates of concern (TTR) and the NC Eastern Coastal Plain

- Norfolk loamy sand

- Cotton Scenario.

Peak Concentration (ppb) 46.3

Post

- Breakthrough Mean Concentration (ppb) 31.3

Entire Simu lation Mean Concentration (ppb) 24

Average Breakthrough Time (days) 2371.187

### 18 Throughputs 4.622157

Table 2. Chemical Properties for Groundwater Modeling of penoxsulam + degradates of concern (TTR).

Koc (ml/g) 45.25 Surface Soil Half Life (days) 0 Hydrolysis Half Life (days) 0 Diffusion Coefficint Air (cm2/day) 0.0
Henry's Constant 0.0 Enthalpy (kcal/mol) 0.0

Table 3. Pesticide application scheme used for penoxsulam + degradates of concern (TTR). This application scheme was applied every yea r of the simulation.

Application Days Relative to Emergence Date (05/15) Application Method Application Rate (kg/ha)

20 Above canopy application 0.0603

50 Above canopy application 0.0337

Figure 1. Aquifer Breakthrough Curve for penoxsulam + degradates of concern (TTR) and the NC Eastern Coastal Plain

- Norfolk Loamy Sand

- Cotton Scenario