### UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### MEMORANDUM

Date:

Subject: December 18

, 2014

Sethoxydim. Sectio n 3 Registration fo r Grass Grown for Seed; Request for an Amended Use on Blueberry; Crop Group Conversions: Group 3 to Group 3-07

, Group 8 to Group 8-10, Group 10 to Group 10-10, Group 11 to Group 11-1 0 ; and Crop Subgroup Conversions: Caneberry to Subgroup 13-07 A, Blueberry to Subgroup 13-07B

, Grape to Subgroup 13 -0 7F Except Fuzzy Kiwifruit, Strawberry to Subgroup 13-07G Except Cranberry, Cranberry to Subgro up 13

- 07H

, Canola Seed to Subgroup 20A

, Sunflower Seed to Subgroup 20B Except Safflower, and Cotton Unde lint ed Seed to Subgroup 20C. Summary of Ana l ytica l Chemistry and Residue Data

.

PC Code: 1 2 1001 DP Barcode: 0422744

Decision No.: 487076 Registration No

. : 7969-56 & 7969-58

Petition No.: 4E8239 Re2ulatory Action: Section 3 Registration

Risk Assessment Type: NA Case No.: 2600

TXRNo.: NA CAS No.: 740 5 1-80-2

MRID Nos.: 49257701 & 4925 77 0 2 40 CFR: §180.41 2



### FROM:

THROUGH:



### TO: Peter Savo ia

, Chemist 

# r:;}_ ft £-

# ~**~** Risk Assessment Branch 

### (RAB) V /

Health Effec t s Division ( 7 509 P)

William H

. Donovan

, Ph.D.

,

# Chemi**tt~ ~**  MichaelS. Met z ger, Branch Chief

RAB V/VII

Healt h Effects Division (7509P)

Sidney Jackson/Barbara Madden, RM 

### OS

Minor Use and E mergency Response Branch Regi s tration Divi s ion (7505P)

And

Ronnie J. B ever , Risk Assesso r Risk Assessment Branch ( RAB) VII

Health Effects Division (7509P)

Page 1 of23Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 2 of 23 1.0 Executive Summary

The Interregional Research Project Number 4 (IR

- 4) has submitted a petition for establishing
tolerance s for sethoxydim in or on gr ass grown for seed and a request for an amended use on blueberry. In addition IR

- 4 is also requesting to co nvert the established tolerances for b ulb vegetable crop group 3 to bulb vegetable crop group 3

- 07, fruiting vegetable crop gr oup 8 to fruiting vegetable crop group 8

- 10, citrus fruit crop group 10 to citrus fruit crop group 10

- 10, pome fruit crop group 11 to pome fruit crop group 11

- 10, caneberry to crop subgroup 13

- 07A, blueberry to crop s ubgroup 13

- 07B, g rape to c rop s ubgroup 13

- 07F

, e xcept f uzzy k iwifruit,

s trawberry to c rop s ubgroup 13

- 07G, c ranberry to c rop s ubgroup 13

- 07H

, except strawberry

,
c anola s eed to r apeseed c rop s ubgroup 20A, s unflower s eed to s unflower c rop s ubgroup 20B

, except safflower , and c otton u ndelinted s eed to c ottonseed c rop s ubgroup 20C

.

Adequate residue chemistry data have been provided to support the new use requests for sethoxydim

. The nature of the residue in plants is adequately understood for the purposes of this petition based on previously review ed plant metabolism studies. Field trials are of adequate number and geographic representation. Crop field trial data analyses employ ed validated analytical methods that determine the residue of concern via common moiety , and are supported by adequate storage stability data. An adequate analytical enforcement method is available to
enforce sethoxydim tolerances. Tolerance recommendati ons were based on use of the Organization for Economic Cooperation and Development (OECD) Maximum Residue Limit (MRL) calculation procedures , international harmonization considerations, and data translation where appropriate. No processing studies were re quired to support the proposed uses.

P reviously reviewed field rotational crop studies support the rotational crop restrictions specified

on the main label

.

2.0 R egulatory R ecommendations

Pending submission of a revised Section F as detailed in Sectio n 2. 2 .2 and a revised Section B as
indicated in Section 2.3

, there are no residue chemistry considerations that would preclude
establishment of the re commended tolerances

.

2.1 Data Deficiencies/Data Needs

T here are no residue chemistry deficiencies identified for this petition.

The re sidue chemistry data base is complete for sethoxydim and no outstanding data are required

. The additional safflower field trial and storage stability data required by the 2005 Reregistration Eligibility Decision (RED) has been adequately fulfilled (D312563, D. Soderberg, 04/12/2012).

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

An adequate gas chromatography/flame photometric detection GC/ F PD method is available ( Method I in PAM Vol. II) for determining the combined residues of sethoxydim and its metabolites containing the 3

- alkyl substituted pentanedioic acid moiety in plant and livestockSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 3 of 23 commodities ( D312567, W. H. Donovan, 04/22/2005 )

. This common moiety method involves solvent extraction followed by alkaline precipitation

, acidification

, and partitioning to convert sethoxydim and its metabolites into the 3

- alkyl substituted pentanedioic acid moiety . The acid moiety is methylated to dimethyl 3

- [2

- (ethylsulfonyl )propyl]pentanedioate (DME) and dimethyl
3

- [2

- (ethylsulfonyl)propyl]3

- hydroxy pentanedioate (DME

- OH) . These derivatives are then partitioned into methylene chloride and cleaned up by silica gel chromatography. Analysis is performed by GC/FPD which provid es a 0.05 ppm limit of quantitation (LOQ).

2.2.2 Recommended Tolerances

Table 2.2.2 summarizes the sethoxydim tolerances resulting from the current petition.

Table 2.2.2. Tolerance Summary for Sethoxydim 1

.

Commodity Proposed
Tolerance (ppm) Recommended

Tolerance (ppm) Comments; Correct Commodity Definition Fruit, citrus, group 10

- 10 0.5 0.5 Fruit, pome, group 11

- 10 0. 2 0.2 Fruit, caneberry, subgroup13

- 07A 5.0 5.0 Caneberry subgroup 13

- 07A Fruit, bushberry, subgroup13

- 07B 5.0 4.0 Bushberry subgroup 13

- 07B

Fruit, small, vine climbing, except fuzzy kiwifruit, subgroup 13

- 07F 1.0 1.0 Fruit, small, vine climbing, subgroup 13

- 07F, except fuzzy
kiwifruit Fruit, low growing berry, except cranberry, subgroup 13

- 07G 10.0 10.0 Berry, low growing, subgroup
13

- 07G, except cranberry Fruit, low growing berry, subgroup
13

- 07H 2.5 2.5 Berry, low growing, subgroup
13

- 07H, except strawberry Rapeseed, subgroup 20A 35.0 35.0 Sunflower, except safflower, subgroup 20B 7.0 7.0 Sunflower subgroup 20B, except safflower Cottonseed, subgroup 20C 5.0 5.0 Vegetable, bulb, group 3

- 07 1.0 1.0 Vegetable, fruiting, group 8

- 10 4.0 4.0 Grass, forage, fodder and hay, group 17, forage 6.0 7.0 2

Grass, forage, fodder and hay, group 17, hay 4.0 4.0 2

1 Th ese tolerance s should be established under 40 CFR §180. 4 12 (a)

. 2 These tolerances should be established under 40 CFR §180. 412(c).



### Note to RD: Upon establishment of the recommended tolerances listed above, tolerance listings for the following individual crops should be revoked since they will be included in the new crop group and crop subgroups listings: blueberry, borage meal, bora ge seed, canola seed, cotton undelinted seed, crambe seed, cupea seed, echium seed, flax seed, gold of pleasure seed, grape, hare’s ear mustard seed, juneberry, lesquerella seed, lingonberry, lunaria seed, meadowfoam seed, milkweed seed, mustard seed, oil radish seed, poppy seed, rapeseed seed, salal, sesame seed, strawberry, sunflower seed, and sweet rocket seed. T he crop group and subgroup listings for caneberry subgroup 13A, citrus fruit group 10, pome fruit group 11, bulb vegetable group 3,
and fruitin g vegetable group 8 are also to be removed and replaced by the current crop group
definition s

. In addition, t he established tolerance for sugar beet tops should be revoked since this commodity is no longer a significant livestock feed or a recognized huma n food item

. TheSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 4 of 23 tolerance with regional registration listed for rhubarb should also be revoked, since this commodity is included in crop group 4 which has an already established tolerance.

The tolerance expression for sethoxydim has been reviewed and should be updated as follows based on HED’s Interim Guidance on Tolerance Expressions (S. Knizner, 05/27/2009).

Tolerances are established for the herbicide sethoxydim, including its metabolites and
d egradates, in or on the commodities in the table below. Compliance with the tolerance levels specified below is to be determined by measuring only the sum of DME (dimethyl
3

- [2

- (ethylsulfonyl)propyl]pentanedioate) and DME

- OH (dimethyl 3

- [2

- (ethylsulfonyl)propyl]3

- hydroxy pentanedioate)

, calculated as the stoichiometric equivalent of the parent compound , in or on the commodity.

2.2.3 Revisions to Petitioned

- For Tolerances

The crop group conversion requested for the low growing berry subgroup 13

- 07G based on strawberry was not specified in Section F of the petition. The tolerance for the bushberry subgroup 13

- 07B is recommended to follow the residue data acquired for the blueberry representative crop at 4.0 ppm and not the previously established tolerances for juneberry

, lingonberry , an d salal at 5.0 ppm . The juneberry

, lingonberry , and salal tolerances are based on
the translation of can e berry data which is no longer relevant to these crops following updated

crop group ing realignment. In addition, the OECD MRL calculation procedures d etermine the recommended tolerance of 7.0 ppm for grass forage and not 6.0 ppm as proposed by the petitioner. This difference stems from the conclusion that only 4 independent grass trials were conducted instead of 5 (as assumed by IR

- 4). Therefore, th e petitioner must submit a revised Section F in which the proposed tolerances are the same as those recommended by HED.

2.2.4 International Harmonization

There are no Codex or Mexican m aximum r esidue l imits (MRLs) established for the residues of sethoxydim in/on raw agricultural or processed commodities. However, t here are established MRLs for sethoxydim in Canada which have harmonized t olerance definitions with the U.S. All Canadian MRLs are harmonized with U.S. tolerances to the greatest exten t possible. In regard to
the grass forage and hay tolerances requested in th is petition , Canada does not establish MRLs
on livestock feed items so harmonization is not a consider ation for these uses. The data provided in support of the requested amended use on b lueberry is consistent with the established 4.0 ppm
U.S. tolerance on this commodity. For the requested crop group conversions, these tolerances are supported by extension of the representative crop (s) already established for use

. As such, the

es tablishment of subgroup 13

- 07B for bushberry will follow the representative crop of blueberry and the set tolerance of 4.0 ppm. Although the bushberries of juneberry, lingonberry, and salal
have established U.S. tolerance s of 5.0 ppm, th ese limits were se t on translation from caneberry data which is no longer a crop in this subgroup. Therefore, in following the blueberry representative crop, the bu shberry subgroup will harmonize with the already established
Canadian MRL of 4.0 ppm for this crop grouping

. For the other conversions, the Canadian

MRLs on rapeseed (canola)

, grapes, cranberry, and bulb vegetables are significantly less than those needed to cover the residues in the U.S. Thus, tolerance harmonization for these crop grouping s are not possible.Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 5 of 23 2.3 Label Recommendations

The supplemental label for fine fescue grown for turfgrass seed should indicate the use is restricted to the Pacific Northwest region of the United States.

3.0 Introduction

3.1 Chemical Identity

Table 3. 1. Sethoxydim and Metabolite Nomenclature

. Chemical structure

Common name Sethoxydim
Company experimental name BAS 9052 H or BAS 562 05H

IUPAC name (±)

- (EZ)

- 2

- (1

- ethoxyiminobutyl)

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxycyclohex

- 2

-

enone

CAS name (±)

- 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

-

one CAS registry number 74051

- 80

- 2

End

- use product (EP) 1.5 lb/gal EC formulation (Poast® Herbicide; EPA Reg. No. 7969

- 58)

Chemical structure of 2

- cyclohexen

- 1

- one metabolites

Derivatized residues determined by the analytical
method

Common and chemical names DME; 3

- [2

- (ethylsulfonyl)propyl]

- pentanedioic acid dimethyl ester DME

- OH; 3

- [2

- ethylsulfonyl)propyl]

- 3

- hydroxypentanedioic acid dimethyl ester
Metabolites used for sample
fortification 1

Common and chemical names MSO; 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylsulfinyl)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one 5

- OH

- MSO 2 ; 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylsulfonyl)propyl]

- 3,5

- dihydroxy

- 2

- cyclohexen

- 1

- one

1 Sethoxydim is readily oxidized to MSO and 5

- OH

- MSO 2 in air; therefore, these metabolites are used for sample

fortification.Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 6 of 23 3.2 Physical/Chemical Characteristics

P hysiochemical properti es for sethoxydim are shown in Table 3.2.

T able 3 .2. Physicochemical Properties of Sethoxydim.

Parameter Value Reference

Color Brown MRID No. 41607203 Physical State Viscous Liquid

Odor Garlic

- Like Boiling Point >130 °C at 6 x 10

- 1 mm Hg Density, Bulk Density, or Specific Gravity 1.058 specific gravity at 20 °C Solubility Water at 25 °C : 2.57 x 10 2 ppm at pH 5, 4.39 x 103 ppm at pH 7; Organic solvents (methanol, n

- octanol, ethyl

acetate, n

- hexane, toluene, xylene, and olive oil) at 20 °C : freely soluble (>10 3 g/100mL). MRID Nos. 41475201 and
41510601

Vapor Pressure 1.6 x 10

- 7 mm Hg at 25 °C MRID No. 00047647

Dissociation Constant pK a is 4.6 at pH 4.5 and 25 ° C MRID No. 000476 50

Octanol/Water Partition Coefficient K OW is 3.26 x 10 3 at pH 5; 45.1 at pH 7; 0.93 at pH 9 MRID No. 41475202

pH 3.95 at 20 °C MRID No. 41607203 Stability Stable at normal temperatures (24 °C ) and in the presence of metals (zinc and iron powder) , unstable at elevated te m peratures (54 °C ) and in the presence of sunlight.



### 3.3 Pesticide Use Pattern/ Directions for Use (860.1200)

A summary of the use directions for the requested new uses on blueberry and fine fescue grasses is provided below in Table 3.3

.

Table 3.3. Summary of Directions for Proposed Uses of Sethoxydim

. Applic. Timing; Type; and Equip. Formulation

[EPA Reg. No.] Applic.

Rate (lb ai/A) Max. No.

Applic. per
Season Max. Seasonal

Applic. Rate (lb ai/A) PHI

(days) Use Directions and Limitations

Blueberry, highbush

Broadcast foliar; Apply as a selective control for grass
weeds ; Ground or aerial equipment Poast TM 1.5

lb/gal
Emulsifiable
Concentrate (EC) [ 7969

- 58 ] 0.5 2 1 .0 1 For the control of perennial and
annual weeds. Make up to 2 applications, each at 2.5 pints per acre, at a
14

- day mi n i m

um interval with the last application 1

- day prior
to harvest.

Fine Fescue Grasses

Broadcast foliar; Apply when fine
fescue is semi

dormant ; Ground and Aerial equipment Poast TM 1.5

lb/gal
Emulsifiable
Concentrate (EC) [ 7969

- 58] 0.5 2 1.0 14 For the control of perennial and
annual weeds. Make up to 2 applications, each at 2.5 pints per acre, at a
30

- day interval with the last application 14

- days prior to foraging or collection of hay. Apply when fine fescue is
semi

- dormant (generally Nov. 1 through March 15).Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 7 of 23 The use directions are adequate to allow evaluation of the residue data relative to the proposed uses. The proposed maximum application rates

, re

- treatment intervals

, and pre

- harvest intervals

a re supported by the submitted field trial data. The fine fescue grass supplemental label should indicate that use is limited to the Pacific Northwest region of the United States.

4.0 Metabolite/Degradate Residue Profile

4.1 Nature of the Residue

4.1.1 Summary of Plant Metabolism (860.1300)

The nature of the residue in plants is adeq uately understood for purposes of the crops that are the subject of this petition. The qualitative nature of the residue in plants is adequately understood based on soybean, tomato, and sugar beet metabolism studies. Sethoxydim is rapidly
metabolized in plants to a multitude of cyclohexenone derivatives including the corresponding parent sulfoxide, parent sulfone, their hydroxylated and desethoxylated analogs, and oxazole compounds; very little (≤0.5%) sethoxydim is left un

- metabolized. The residues of c oncern for tolerance expression and risk assessment in plants are the combined residues of sethoxydim and its metabolites containing the 2

- cyclohexen

- 1

- one moiety (calculated as sethoxydim).

4.1.2 Summary of Livestock Metabolism (860.1300)

The nature of the residue in livestock is understood based on acceptable metabolism studies in ruminants (goat) and poultry (hens). The residues of concern for tolerance expression and risk

assessment in livestock commodities are the combined residues of sethoxydim and its metabolites containing the 2

- cyclohexen

- 1

- one moiety (calculated as sethoxydim)

.

4 .2 Residues of Concern Summary and Rationale

The metabolism of sethoxydim in plants and livestock is adequately understood. Residues of concern for both tolerance expression and risk assessment are the combined residues of sethoxydim and its metabolites containing the 2

- cyclohexen

- 1

- one moiety, calculat ed as sethoxydim (Phase V Review of soybeans, tomatoes, Goats, and poultry Metabolism Studies

, CBRS17851, L. Cheng, 04/04/97). The Metabolism Assessment Review Committee (MARC)
has also met and discussed the residues of sethoxydim which are found in water (D246356, R. Loranger, 05/27/1998). The predominant degradates in soil are the sulfoxide and sulfone derivates of parent (MSO and MSO2). Those degradates are expected to be found in water along with M1S (loss of ethoxy group on imino nitrogen) and M2S ( formation of oxazole ring). In the
absence of available toxicity data, the MARC con siders the degradates of sethoxydim as having comparable toxicity to that of the parent compound. Th er e fore, the MARC concluded that for risk assessment purposes the resid ues in water are the “total sethoxydim residues” in water (parent plus degradates).Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 8 of 23 Table 4.2 Summary of Metabolites and Degradates to be included in the Risk Assessment and Tolerance Expression

Matrix Residues included in Risk Assessment Residues included in Tolerance Expression

Plants (Primary and Rotational Crops) Sethoxydim and all metabolites containing

the 2

- cyclohexen

- 1

- one moiety Sethoxydim and all metabolites containing
the 2

- cyclohexen

- 1

- one moiety

Livestock Sethoxydim and all metabolites containing

the 2

- cyclohexen

- 1

- one moiety Sethoxydim and all metabolites containing
the 2

- cyclohexen

- 1

- one moiety

Drinking Water Total sethoxydim residues (parent plus

degradates) Not Applicable



### 5.0 Residue Profile

5.1 Residue Analytical Methods (860.1340)

5.1 .1 Data Collection Methods

Samples from the current grass and blueberry field trial s tudies were analyzed for the combined
residues of sethoxydim and its metabolites convertible to the 3

- alkyl substituted pentanedioic

ac id moiety using GC/ FPD method ology . Th e GC/FPD methods used for these analyses are
derived from the current tolerance enforcement method

, BASF Wyandotte Corporation Method No. 30, included in Method I PAM II. These methods are determined to be adequate for data collection based upon acceptable concurrent recovery provided with each study.

Briefly, residues are extracted with methanol, evaporated, reconstituted, and precipitated with calcium hydroxide. Aft er filtration, the extract was acidified and then partitioned four times with dichloromethane (DCM). Sethoxydim and its metabolites were oxidized with hydrogen peroxide at reflux, and then esterified with acidic methanol to DME and DME

- OH. The derivative s were partitioned into DCM, evaporated to dryness, re

- dissolved in acetone, and determined by GC/FPD in the sulfur mode. Residues are expressed as sethoxydim using molecular weight
conversion factors of 1.11x for DME and 1.05x for DME

- OH.

5.1.2 Multi

- Re sidue Methods (860.1360)

Sethoxydim is not recovered through the PAM I multi

- residue methods.

5.1 .3 Tolerance Enforcement Methods

A n a dequate enforcement methodology using GC/FPD analysis is available for determining the residues of sethoxydim. BASF Wyandotte Corporation Method No. 30, "Determination of BAS 9052H and its Metabolites in Soybean Seed, Soybean Seed Process Fractions, Chicken Tissues, Beef Tissues, Milk and Eggs", is designed to determine residues of sethoxydim and its metabolites, includ ing the parent sulfoxide (MSO), the parent sulfone (MSO 2 

### ) and hydroxylated derivatives (e.g. 5

- OH

- MSO 2 

### ). Residues are determined as 3

- [2

- (ethylsulfonyl)

- propyl] pentanedioic acid dimethyl ester (DME) and its 3

- hydroxy derivative: 3

- [2

- (ethoxysulfonyl)Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 9 of 23 pro pyl]

- 3

- hydroxypentanedioic acid dimethyl ester (DME

- OH), respectively. The limit of quantitation for each analyte is reported to be 0.05 ppm sethoxydim equivalents. Method 30 is included as Sethoxydim Method I in PAM II

, and is therefore approved as an enforcement
method.

5.1.4 Submittal of Analytical Reference Standards (860. 1650)

A nalytical standard s for sethoxydim (CAS # 74051

- 80

- 2 ) and its regulated metabolites are
available at the EPA National Pesticide Standards Repository [personal communicati on from T.
Cole of ACB/BEAD to K. King

, 0 9 /2 9 /201 4 ] with the following receipt and expiration dates:

Inventory
Chemical Name Company Date Exp sethoxydim 5

- hydroxy sulfone (see sethoxydim , 5

- OH

- MSO2) sethoxydim sulfone (183612) BASF 6/1/2016 sethoxydim sulfoxide Nisso
Chem 9/29/2008

sethoxydim sulfoxide (0183611) BASF 6/1/2016 sethoxydim sulfoxide (0183611) BASF 2/1/2015 sethoxydim, use li

- sethoxydim see folder BASF sethoxydim, 5

- OH

- MSO2 248657 BASF 3/1/2015 sethoxydim, 5

- OH

- Sulfoxide 248657 BASF 3/1/2015 sethoxydim, DME metabolite 229159 BASF 4/1/2024 sethoxydim, DME

- OH metabolite BASF 4/1/2020 sethoxydim, li (reg 282305) BASF 2/1/2016

Prior to the listed expiration dates, fresh standards should be re

- submitted to the Repository. The
reference standard (s) should be sent to the Analytical Chemistry Lab, which is located at Fort Meade, to the attention of Theresa Cole at the following address:

USEPA National Pesticide Standards Repository/Analytical Chemistry Branch/OPP 701 Mapes Road Fort George G. Mea de, MD 20755

- 5350

The full 9 digit zip code is mandatory or the mail will be returned.

5.2 Storage Stability (860.1380)

Adequate storage stability data are available depicting the stability of sethoxydim residues held under frozen storage conditions a t durations incurred for the studies supporting this petition. For the field trial studies carried out for grass, forage and hay samples were stored frozen (

- 21 ± 7Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 10 of 23 °C) from collection to extraction for 108

- 123 days (3.6

- 4.0 months) and 172

- 272 days (5.7

- 8 .9 months), respectively. All samples were analyzed within 2

- 4 days of extraction. Storage stability data were generated concurrently with the field trial study to demonstrate that residues of sethoxydim, determined as DME and DME

- OH are stable in grass commodities when stored
frozen for these durations. For the blueberry field trials, t he maximum sample storage interval between harvest and analysis was 848 days (28.2 months). Residues of sethoxydim have been
shown to be stable in strawberries stored frozen for up to 3 1 months (D219970, L. Cheng, 04/09/1996)

. As a result, a dequate data are available to support the storage conditions and
intervals for the blueberry samples comprising the current trials.

5.3 Residue Data

5.3.1 Crop Field Trials (860.1500)

4 9257701 .der ( Blueberry Trials )

4 925770 2 .der ( Grass Grown for Seed Trials)



### Blueberry Trials The Interregional Research Project No. 4 (IR

- 4) submitted magnitude of the residue data for sethoxydim on blueberry grown in both the United States and Canada

. Eleven (11) field trials
for sethoxydim on blueberries in all were conducted in the North American Free Trade Agreement (NAFTA) Growing Regions 1A (3 trials in NS), 1 (1 trial in ME), 2 (3 trials in NC), 5A (3 trials in MI) and 12 (1 trial in OR) during the 2008 growing season. Of these 11 field trials, 4 were conducted on lowbush blueberries and 7 were conducted on highbush blueberries.

The trials reflect the use of two post

- emergent foliar applications of sethoxydim formu lated as
the 1.5 lb. ai/ gal POAST® emulsifiable concentrate (EC) h erbicide . Treatments were made at a rate of 0.476

- 0.523 lbs ai/A (534

- 586 g ai/ha) for a total seasonal rate of 0.961

- 1.019 lbs ai/A (1078

- 1142 g ai/ha). A re

- treatment interval (RTI) of 1 3

- 16 days and a 1

- day pre

- harvest interval (PHI) was followed. An adjuvant or crop oil concentrate was added to the spray mixture for all applications.

All samples were maintained frozen at the testing facility, during shipping to the laboratory, an d were stored frozen until analysis. The maximum storage interval for samples between harvest and analysis was 848 days (28.2 months). Residues of sethoxydim have been shown to be stable in strawberries for up to 31 months under frozen conditions (D21997 0, L. Cheng, 04/09/1996)

. Translating the strawberry storage stability data to blueberry, a dequate storage stability data are available to support the storage conditions and intervals for samples in the current trials.

The blueberry samples in this study were analyzed using Method Version #36, a GC/FPD method to determine residues of sethoxydim derived from the Method I PAM II enforcement
method. Acceptable method validation and concurrent recoveries were reported for blueberry samples at fortification levels of 0.05 ppm, 0.50 ppm, 5.0 ppm and/or 15.0 ppm with the exception of one concurrent recovery at 67%, thus validating the method. The limit of quantitation (LOQ) was determined to be 0.05 ppm for each analyte ( i.e. MSO and 5

- OH

- MSO 2 

### ) in blueberries which corresponds to a LOQ of 0.047 ppm for DME and 0.044 ppm for DME

- OH (expressed as sethoxydim equivalents).Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 11 of 23 Individual sample (and per

- trial average) residues in lowbush blueberries ranged from 0.164 ppm to 8.92 p pm (3.34 ppm to 8.72 ppm) when treated at a total rate of 0.961

- 1.019 lbs ai/ha (1078

- 1142 g ai/ha) and sampled 1 day after treatment. Individual sample (and per

- trial average) residues in highbush blueberries ranged from <0.091 ppm to 0.204 ppm (<0.091 p pm to 0.184 ppm) when treated at a total rate of 0.978

- 1.078 lbs ai/ha (1096

- 1208 g ai/ha) and sampled 1 day
after treatment. The results from these studies are summarized in Table 5.3.1.1.

Table 5.3.1.1. Summary of Residues from Blueberry Field Trials with Sethoxydim

Crop Matrix Total Application

Rate (lbs ai/A) [g ai/ha] PHI

(days) n Residues 1 (ppm)

Min. 2 Max. 2 LAFT 3 HAFT 3 Median 3 Mean 3 SD 3

LOWBUSH BLUEBERRIES

Lowbush
blueberries 0.961

- 1.019

[1078

- 1142] 1 4 0.164 8.92 3.34 8.72 7.72 6.88 2.41

HIGHBUSH BLUEBERRIES Highbush
blueberries 0.978

- 1.078

[1096

- 1208] 1 7 0.091 0.204 0.091 0.184 0.091 0.106 0.035

1 Combined residues of DME and DME

- OH expressed as sethoxydim equivalents.

2 Values based on total number of samples.

3 Values based on per

- trial averages. LAFT = lowest average field trial, HAFT = highest average field trial, SD = standard deviation. For computation of the LAFT, HAFT, median, mean, and standard deviation, values < LOQ are assumed to be at the LOQ (xx pp m).
n = number of field trials.



### Conclusions: The current petition requests only to amend the use of sethoxydim on highbush
blueberries to a reduced 1

- day PHI. All other bushberry varieties, including lowbush blueberries, will retain t he established labe led rate which follows a 30

- day PHI. As a result

, the lowbush blueberry data acquired at the 1

- day PHI contained in this study are not used for tolerance setting purposes since they do not reflect a proposed or registered use pattern

. Although eight (8) highbush blueberry trials are recommended for tolerance determination, the seven (7) provided are considered adequate due to the consistently low residues observed

. All highbush blueberry samples acquired for study were analyzed using an adequat e analytical method with the incurred storage intervals appropriately supported by available stability data. The current tolerance set on blueberries is 4.0 ppm and this limit remains adequate given that all of the highbush blueberry data acquired at the 1

- day PHI are well below this l evel

.

Grass Grown for Seed Trials

IR

- 4 submitted field trial data for sethoxydim on fine fescue grass grown for seed. Five (5) grass field trials were conducted in the United States in NAFTA Zones 11 (WA; 2 t rials) and 12 (OR; 3 trials) during the 2007 growing season. Careful examination of the field trial records indicates that the two WA trials were conducted at the same locations with very few differences in study design; for this reason HED has determined these trials constitute a single trial with replicate samples for purposes of 860.1500 data requirements. The three OR trials were also conducted at the same location; however, HED has concluded that these may be considered independent due
differences in the grass variety used.

The trials reflect the use two foliar broadcast applications of sethoxydim formulated as the 1.5 lb. ai/gal POAST® emulsifiable concentrate (EC) h erbicide . Treatments were made at 0.465

- 0.498
lb ai /A/application for a total seasonal rate of 0.936

- 0.973 lb ai/A. Applications were made at
30

- to 44

- day retreatment intervals (RTIs) using ground equipment in spray volumes of 14.9

-Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 12 of 23 20.3 gal/A. A crop oil concentrate (COC) was added to each spray mixture . Following the second application, samples were harvested from all trials at preharvest intervals (PHIs) of 13

- 14 days for grass forage and 21

- 28 days for grass hay. Hay samples were allowed to dry in an
enclosed area for 3

- 7 days prior to collection.

Samples of grass forage and hay were stored frozen (

- 21 ± 7 °C) from collection to extraction for
108

- 123 days (3.6

- 4.0 months) and 172

- 272 days (5.7

- 8.9 months), respectively. All samples were analyzed within 2

- 4 days of extraction. Storage stability data generated concurrently with the field trial study to demonstrate that residues of sethoxydim, determined as DME and DME

OH, are stable on grass samples for these durations.

The gras s forage and hay samples in this study were analyzed using Method Version #3 5 and
35A , a GC/FPD method to determine residues of sethoxydim derived from the Method I PAM II
enforcement method. The method is adequate for data collection based on acceptable concurrent recovery data. The calculated LOD and LOQ for DME and DME

- OH in fine fescue grass forage

were determined to be 0.007, 0.021, 0.005, and 0.014 ppm, respectively. The calculated LOD and LOQ for DME and DME

- OH in fine fescue grass hay were determined to be 0.013, 0.038, 0.004, and 0.011 ppm.

Following two fol iar broadcast applications of the 1.5 lb ai/gal EC formulation of sethoxydim at
a total rate of 0.936

- 0.973 lb ai/A, residues (and per trial averages) of sethoxydim equivalents, (determined as DME, DME

- OH, and combined residues; respectively, were: 1.0

- 2.8 (1.4

- 2.7),
0.21

- 0.42 (0.22

- 0.34), and 1.24

- 3.16 (1.65

- 3.04) ppm, in/on fine fescue grass forage harvested at
a 13

- to 14

- day PHI; and 0.48

- 1.3 (0.65

- 1.1), 0.14

- 0.40 (0.15

- 0.35), and 0.75

- 1.45 (0.98

- 1.26)

ppm , in/on fine fescue grass hay harvested at a 21

- to 28

- day PHI. Residue decline data were not
submitted. The results from these studies are summarized in Table 5.3.1.2.

T able 5.3.1.2. Summary of Residue Data from Grass Crop Field Trials with Sethoxydim.

Commodity Analyte Total App.

Rate ( lb ai /A) PHI

(days) Residue Levels (ppm) 1

n Sample
Min. Sample

Max. LAFT 2 HAFT 2 Median Mean Std.

Dev.

Grass forage DME 3 0.936

- 0.973 13

- 14 4 1.0 2.8 1.4 2.7 1.5 1.8 0.63

DME

- OH 3 4 0.21 0.42 0.22 0.34 0.29 0.29 0.07

Combined 4 1.24 3.16 1.65 3.04 1.74 2.04 0.67

Grass hay DME 3 21

- 28 4 0.48 1.3 0.65 1.1 0.84 0.86 0.19

DME

- OH 3 4 0.14 0.40 0.15 0.35 0.30 0.27 0.09

Combined 4 0.75 1.45 0.98 1.26 1.16 1.14 0.14

1 Except for sample min/max, values reflect per trial averages; n = no. of field trials. For calculation of median, mean, and standard deviation, the LOQ (0.042 ppm for all analytes) was used for any results reported as <LOQ.

2 LAFT = lowest average field trial ; HAFT = highest average field trial.

3 Residues of DME and DME

- OH are reported in sethoxydim parent equivalents as calculated by the petitioner.



### Conclusions: The submitted residue data made for the grass forage and hay commodities are adequate to support a regional registration limiting use to the Pacific Northwest region of the
United States

. The number and location of field trials are sufficient having been made in line with the guidance document , “Grasses Grown for Seed”, an Agency memorandum d ated 09/30/2000. This memorandum requires the collection of forage and hay data for this commodity since it is considered to be a subgroup of grass pasture and rangeland. Further, itSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 13 of 23 specifies that for a national registration, a total of 8 trials are rec ommended (5 in the Pacific Northwest plus 3 in Region 5). HED notes that although according to current policy only 4 independent grass trials were submitted, the trials were conducted prior to when the criteria for distinguishing independent trials became available. In addition, the consistency observed in the data set makes it unlikely that requiring an additional trial would lead to different conclusions
that what can be determined from the results now available. Thus, applying OECD MRL calculation pro cedures to the 4 independent trials gives recommended tolerances of 7.0 ppm for grass forage and 4.0 ppm for grass hay (see Appendix B).

Tolerance Conversions to Crop Groups/Subgroups

 Citrus Fruit Group 10 to Citrus Fruit Group 10

- 10

IR

- 4 proposed that t he established tolerances of 0.5 ppm for citrus fruit crop group 10 be converted to the updated ci t rus fruit crop group 10

- 10 listing at the same limit. This request is supported by the following observations: 1) adequate residue data for the orange, lem on, and grapefruit representative crops were previously submitted and evaluated to establish a citrus fruit crop group tolerance at 0.5 ppm , and 2) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the petition, are cons istent with the requested conversion.

 Pome Fruit Group 11 to Pome Fruit Group 11

- 10

IR

- 4 proposed that the established tolerances of 0. 2 ppm for pome fruit group 11

- 10 be converted

to the updated pome fruit group 11

- 10 listing at the same limit

. This r equest is supported by the following observations: 1) adequate residue data for the apple and pear representative crops were previously submitted and evaluated to establish a pome fruit crop group tolerance at 0.2

ppm , and 2) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the petition, are consistent with the requested conversion.

 Caneberry Subgroup 13A to Caneberry Subgroup 13

- 07A

IR

- 4 proposed that the established tolerances of 5.0 ppm for caneberry subgroup 1 3A be converted to the updated caneberry subgroup 13

- 07A listing at the same limit. This request is supported by the following observations: 1) adequate residue data for the raspberry representative crop were previously submitted and evaluated to establi sh a caneberry subgroup
tolerance at 5.0 ppm , and 2) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the petition, are consistent with the requested conversion.

 Blueberry to Bushberry S ubgroup 13

- 07B

IR

- 4 proposed t hat the established tolerances of 4.0 ppm for b lueberry and 5.0 ppm for juneberry, lingonberry, and salal be converted to the updated bushberry subgroup 13

- 07B listing at 5.0 ppm. This request is supported but at the recommended tolerance of 4.0 ppm and n ot the proposed limit of 5.0 ppm based on the following observations: 1) adequate residue data for the blueberry representative commodit y were previously submitted and evaluated to establish a tolerance of 4.0 ppm on this crop , 2) the juneberry, lingonber ry, and salal tolerances are based on the translation of caneberry data which is no longer relevant to these crops following updated crop group realignment, and 3) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the pe tition, are consistent with the requested conversion.Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 14 of 23  Grape to Crop Subgroup 13

- 07F [ Fruit, small vine climbing, except fuzzy kiwifruit, subgroup 13

- 07F]

IR

- 4 proposed that the established tolerance of 1.0 ppm for grape be converted to crop subgroup
13

- 07F, also at 1.0 ppm. This request is supported by extension of the grape use pattern to include crop subgroup 13

- 07F , as indicated in the proposed revisions to the POAST® EC
herbicide label , submitted as part of Section B of the petition. Grape is the representative commodity for crop subgroup 13

- 07F.

 Strawberry to Crop Subgroup 13

- 07G, Except Cranberry [Berry, low growing, subgroup
13

- 07F, except cranberry]

IR

- 4 proposed that the established tolerance of 10 .0 ppm for strawberry be converted to crop subgroup 13

- 07G, except cranberry, also at 10 .0 ppm. This request is supported by extension of the strawberry use pattern to include crop subgroup 13

- 07G, except cranberry , as indicated in the proposed revisions to the POAST® EC herbicide label , submitted as part of Section B of the petition. Strawberry is the representative commodity for crop subgroup 13

- 07G.

 Cranberry to Crop Subgroup 13

- 07H

IR

- 4 proposed that the established tolerance of 2.5 ppm for cranber ry be converted to crop subgroup 13

- 07 H , also at 2.5 ppm. This request is supported by extension of the cranberry use pattern to include crop subgroup 13

- 07 H , as indicated in the proposed revisions to the POAST® EC herbicide label, submitted as part of Section B of the petition. Cranberry is the representative commodity for crop subgroup 13

- 07 H

.

 Canola Seed to Rapeseed Crop Subgroup 20A

IR

- 4 proposed that the established tolerance of 35.0 ppm for canola seed be converted to crop subgroup 20A, also at 35.0 ppm. This request is supported by extension of the canola use pattern to include rapeseed crop subgroup 20A, as indicated in the proposed revisions to th e POAST® EC herbicide label, submitted as part of Section B of the petition. Canola is the representative commodity for rapeseed crop subgroup 20A.

 Sunflower Seed to Sunflower Crop Subgroup 20B

, Except Safflower

IR

- 4 proposed that the established toler ance of 7.0 ppm for sunflower seed be converted to crop subgroup 20B, also at 7.0 ppm. This request is supported by extension of the sunflower use pattern to include sunflower crop subgroup 20 B

, except safflower, as indicated in the proposed
revisions to the POAST® EC herbicide label, submitted as part of Section B of the petition.
Sunflower is the representative commodity for rapeseed crop subgroup 20A.

 Cotton Undelinted Seed to Cottonseed Crop Subgroup 20C

IR

- 4 proposed that the established tolerance of 5.0 ppm for cot t on undelinted seed be converted to crop subgroup 20C, also at 5.0 ppm. This request is supported by extension of the cotton use pattern to include cottonseed crop subgroup 20C, as indicated in the proposed revisions to the
POAST® EC he rbicide label, submitted as part of Section B of the petition. Cotton is the representative commodity for rapeseed crop subgroup 20C.

 Bulb Vegetable Group 3 to Bulb Vegetable Group 3

- 0 7

IR

- 4 proposed that the established tolerances of 1.0 ppm for bulb vegetable crop group 3 be converted to the updated bulb vegetable crop group 3

- 07 listing at the same limit. This request isSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 15 of 23 supported by the following observations: 1) adequate residue data for the green onion and bulb
onion representative crops were pr eviously submitted and evaluated to establish a bulb vegetable

cr op group tolerance at 1.0 ppm, and 2) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the petition, are consistent with the requested conversion.

 Frui ting Vegetable Group 8 to Fruiting Vegetable Group 8

- 10

IR

- 4 proposed that the established tolerances of 4.0 ppm for fruiting vegetable crop group 8 be converted to the updated fruiting vegetable crop group 8

- 1 0 listing at the same limit. This request is supported by the following observations: 1) adequate residue data for the tomato and

pepper representative crops were previously submitted and evaluated to establish a fruiting vegetable crop group tolerance at 4 .0 ppm, and 2) proposed revisions to the POAST® EC herbicide label submitted as part of Section B of the petition, are consistent with the requested
conversion.

Conclusions: HED concludes that the tolerance conversions propose d by IR

- 4 are acceptable. Upon establishment of the requested crop group/subgroup tolerances, the individual crop
tolerances for blueberry, borage meal, borage seed, canola seed, cotton undelinted seed, crambe seed, cupea seed, echium seed, flax seed, gol d of pleasure seed, grape, hare’s ear mustard seed, juneberry, lesquerella seed, lingonberry, lunaria seed, meadowfoam seed, milkweed seed, mustard seed, oil radish seed, poppy seed, rapeseed seed, salal, sesame seed, strawberry, sunflower seed, and sweet rocket seed should be revoked as they will be included in the group/subgroup tolerance listings. In addition, the crop group and subgroup listings for caneberry subgroup 13A, citrus fruit group 10, pome fruit group 11, bulb vegetable group 3, and fruiting vegetable group 8 are also to be removed and replaced by the current crop group
definitions.

5.3.2 Field Rotational Crops (860.1900 )
D312567, W.H. Donovan, 04/22/2005



### An adequate limited field study using soybeans and cotton treated with 14 

### C

- ring

- labe led sethoxydim was submitted by the registrant. Following treatment and harvest, selected rotational crops of leafy vegetable, root crop, and small grain groups were sown at intervals to simulate emergency replant, fall crop rotations, and annual crop rot ations. Total radioactive residues (TRRs) were <0.005

- 0.01 ppm with some exceptions: 0.05 ppm in sorghum forage at a plant

back interval (PBI) of 30 days (0.5 lb ai/A application rate); 0.02 ppm in winter wheat forage and 0.05 ppm in winter wheat straw at a PBI of 134 days (1 lb ai/A application rate); and 0.024 ppm in spring wheat grain and 0.06 ppm in spring wheat straw at a PBI of 283 days (0.5 lb ai/A application rate). HED noted that even though the application rate in cotton was below the
maximum fo r this crop, it was similar to that of many other crops. The chance that using the highest possible application rate could lead to rotational crop residues in excess of the LOQ is judged unlikely. Given that the sethoxydim residues appear to be below the LOQ in all rotational crops at all PBIs and tolerances have been established for representative crop s of the leafy vegetable and root crop groups, HED concluded that no tolerances on rotational crop are required for plant

- back times greater than 30 days. In addition, HED noted that the label prohibits planting crops not registered for the product for 120 days after application (D189273, G. Kramer, 0 8/ 0 3/ 19 93).Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 16 of 23 5 .3.3 Processed Food and Feed (860.1520)

There are no processed commodities associated with gra ss grown for seed or blueberry. Therefore, data requirements for processed food and feed are not relevant to this tolerance petition.

5.3.4 Meat, Milk, Poultry and Eggs (860.1480) Chemistry Chapter of the Re registration Eligibility Decision

, D 312567

, W . H. Donovan, 04/22/2005



### For this action, the recommended tolerance s for grass forage and hay are 7.0 ppm and 4.0 ppm, respectively. The sethoxydim maximum theoretical dietary burdens to livestock were previously calculated in the residue chemistry summa ry for the 2005 RED. G rass forage and hay are both
classified as roughage s. A tolerance of 40.0 ppm on alfalfa forage, another livestock roughage feed item, was i ncluded in the maximum theoretical dietary burden calculation in 2005 ; therefore, the addition of th ese new tolerance s will not increase the previously calculated dietary
burden. If HED were to recalculate the MRBD burden for sethoxydim at this time, grass forage and hay be superseded by alfalfa forage, and the use of STMR and HR values wo uld substantially reduce the dietary burden compared to the 2005 value

. Current sethoxydim

t olerances in livestock commodities are based on the conservative 2005 RED dietary burden ; therefore, current livestock tolerances are adequate to support th e new u se s proposed for sethoxydim.

5.4 Food Residue Profile

Adequate residue chemistry data have been provided to support the registration of sethoxydim on on grass grown for seed and its amended use on blueberry. Field trials are of adequate number and geographic representation. Data analyses employed validated analytical methods and are supported by adequate storage stability data. No processing studies were submitted because sethoxydim use i n grass grown for se ed and blueberry are not expected to be processed for
economic reasons. For the requested new use on grass grown for seed, the establishment of tolerances on grass forage and hay will not increase livestock dietary burden; therefore, no new
revised tolera nces on livestock commodities are required.

The nature of the residue in plants and livestock is adequately understood. The residues of concern in plants and livestock are the combined residues of sethoxydim and its metabolites containing the 2

- cyclohexe n

- 1

- one moiety (calculated as sethoxydim). For risk assessment purposes, the residues in water are parent plus degradates. The degradates which are expected to be found in water are the sulfoxide and sulfone derivatives of the parent (MSO and MSO2) along with M1S (loss of ethoxy group on imino nitrogen) and M2S (formation of oxazole ring).

No tolerances have been established for inadvertent or indirect residues of sethoxydim in or on rotational crops and none are needed at this time.

6.0 Tolerance Derivation s

The recommended tolerances for sethoxydim were derived by 1) use of the OECD MRL calculation procedures for grass forage and hay

, and 2) direct translation of the establishedSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 17 of 23 representative crops for the crop group conversions that were reques ted. The calculated tolerances for grass forage is 7.0 ppm and 4.0 ppm for grass hay. For these calculations,

e xamination of the field trial records showed that the two WA trials were conducted at the same locations with very few differences in study des ign; for this reason HED has determined these trials constitute a single trial with replicate samples . Consequently, the four replicate residue values from the WA trial were averaged prior to use in the OECD calculator as a single value

. Listings of the OECD MRL calculator input and output for grass forage and hay are provided in Appendix B.

List of Appendices
A. International Residue Limits Table.

B. Tolerance Calculations

. C. 49257701.der.docx [blueberry trials]

D. 49257702.der.docx [grass grown for seed trials]Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 18 of 23 References

DP No. : D312563
Sub ject: Sethoxydim: Submission of a Study of Residues on Safflower in Response to a

RED Data Gap Requirement

From: D

. Soderberg

To: J. Parker
Dated: 04 /1 2/ 2012

MRID No. : 48514501

DP No. : D312567
Sub ject: Sethoxydim

. HED Chemistry Chapter of the Reregistration Eligibility Decision

(RED). Summary of Analytical Chemistry and Residue Data. Case No. 2600.

From: W. H. Donovan

To: A. Johnson
Dated: 0 4 /2 2 / 2005

MRID No. : None

DP No. : None
Sub ject: Sethoxydim

. Case 2600. Phase V Review of Soybeans, Tomatoes, Goats, and

Poultry Metabolism Studies. CBRS 17851. DP Barcode : None.

From: L. Cheng

To: K. Whitby
Dated: 04/ 04 / 1997

MRID No. : None

DP No. : D246356
Sub ject: Sethoxydim

. Conclusions of the 05/14/98 Meeting of the Metabolism

Assessment Review Committee.

From: R

. Loranger

To: G. Kramer
Dated: 0 5 / 27 /199 8

MRID No. : None

DP No. : D219970
Sub ject: Sethoxydim

. Case 2600. Craven Replacement Data: Freezer Storage in Fruit and

Vegetable Crops; Residue in Tomatoes, Broccoli, Mustard Greens, and Cabbage.

From: L. Cheng

To: B. Adler
Dated: 04/09/1996

MRID No. : 43801401

- 43801405Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 19 of 23 DP No. : D 189273
Sub ject: ID# 121001

- 007969. Review of Rotational Crop Studies of Sethoxydim (Poast

Herbicide, EPA Reg. No. 7969

- 58). MRID Nos. 42825 and 415106

- 12. Barcode
D189273. Case 816519. CBTS# 11575.

From: G. F. Kramer

To: K. Davis
Dated: 0 8 /0 3 /199 3

MRID No. : 42825 and 415 106

- 12Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 20 of 23 Appendix A . International Residue Limits Table

Table B1. Summary of US and International Tolerances and Maximum Residue Limits for Sethoxydim (121001) Residue Definition :
US Canada Mexico 2 

### Codex

40 CFR 180.412:
Plant: sethoxydim: 2

- [1

- ethoxyimino)butyl]

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one (±)

- 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one, including
metabolites containing the cyclohexen

- 2

- one moiety, expressed as sethoxy dim None



### Commodity 1 

### Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico 2 

### Codex
Fruit, citrus, group 10

- 10 0.5 Fruit, pome, group 11

- 10 0.2 Fruit, caneberry, subgroup 13

- 07A 5.0 5 raspberries Fruit, bushberry, subgroup 13

- 07B 4.0 4 aronia berries, buffalo currants, Chilean guavas, currants, elderberries, European barberries, gooseberries, highbush (blueberries, cranberries), honeysuckle, huckleberries, jostaberries, Juneberries (Saskatoon berries), lingonberries

, lowbush blueberries, native currants, salal berries, sea buckthorn Fruit, small vine climbing, except fuzzy kiwifruit, subgroup 13

- 07F 1.0 0.2 amur river grapes, , grapes, hardy kiwifruit, maypop, schisandra berries

4 gooseberries

0.6 raisins

Fru it, low growing berry, except cranberry, subgroup 13

- 07G 10.0 2 cranberries

4 lowbush blueberries, lingonberries

10 strawberry Fruit, low growing berry, except strawberry, subgroup 13

- 07H 2.5 2 cranberries

4 lowbush blueberries, lingonberries Rapeseed, subgroup 20A 35.0 2.5 borage seeds

0.2 flax seeds

25 rapeseeds (canola) Sunflower, except safflower, subgroup 20B 7.0 7 sunflower seeds

Cottonseed, subgroup 20C 5.0 Vegetable, bulb, group 3

- 07 1.0 0.2 onions Vegetable, fruiting, group 8

- 10 4.0 2 eggplants 0.5 peppers
4 tomatoes 15 tomato pasteSethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 21 of 23 Table B1. Summary of US and International Tolerances and Maximum Residue Limits for Sethoxydim (121001) Residue Definition :
US Canada Mexico 2 

### Codex Grass, forage, fodder and hay, group 17, forage 6.0

Grass, forage, fodder and hay, group 17, hay 4.0

Completed: M. Negussie; 11/13/14

1 Includes only commodities of interest for this action. Tolerance values should be the HED recommendations and not those proposed by the applicant.

2 Mexico adopts US tolerances and/or Codex MRLs for its export purposes.

### Page 22 of 23

Appendix B

. Results of OECD Tolerance Calculations

Sethoxydim
Grass, Crop Group 17, Forage

US

PHI @ 14

- days (EC)

Total number of data (n) 4
Percentage of censored data 0%

Number of non

- censored data 4

Lowest residue 1.650
Highest residue 3.040

Median residue 1.745

Mean 2.045
Standard deviation (SD) 0.665
Correction factor for censoring (CF) 1.000

Proposed MRL estimate

- Highest residue 3.040

- Mean + 4 SD 4.706

- CF x 3 Mean 6.135

Unrounded MRL 6.135

Rounded MRL 7

High uncertainty of MRL estimate.

[Small dataset]

Residues (mg/kg) n

1.65 1

1.72 1

1.77 1

3.04 1Sethoxydim Summary of Analytical Chemistry and Residue Data D422744



### Page 23 of 23 Sethoxydim
Grass, Crop Group 17, Hay

US

PHI @ 21

- 28

- days (EC)

Total number of data (n) 4
Percentage of censored data 0%

Number of non

- censored data 4

Lowest residue 0.980
Highest residue 1.260

Median residue 1.155

Mean 1.138
Standard deviation (SD) 0.140
Correction factor for censoring (CF) 1.000

Proposed MRL estimate

- Highest residue 1.260

- Mean + 4 SD 1.696

- CF x 3 Mean 3.413

Unrounded MRL 3.413

Rounded MRL 4

High uncertainty of MRL estimate.

[Small dataset]

Residues (mg/kg) n

0.98 1

1.06 1

1.25 1

1.26 1Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 1 of 8 

### B.7.6 Residues R esulting f rom S upervised T rials (Annex IIA 6.3 ; Annex IIIA 8.3 )

B.7.6.1 Residues in T arget C rops

B.7.6.1.1 Blueberries (highbush and lowbush)

Document ID: MRID No. 49257701

PMRA No. 2387982 Report: Barney, W. P., Lennon, G. (2011) “Sethoxydim: Magnitude of the Residue

on Blueberry”, IR

- 4 PR No. 09933, Analytical Laboratory Identification
Number 09933.08

- NYR02. Unpublished study prepared by IR

- 4 Project Headquarte rs, Rutgers, The State University of NJ, Princeton, NJ, 304

pages. Guidelines: EPA OCSPP Harmonized Test Guideline 860.1500 Crop Field Trials

(August 1996) PMRA Regulatory Directive DIR98

- 02

– Residue Chemistry Guidelines,
Section 9

– Crop Field Trials

P MRA Regulatory Directive DIR 2010

- 05

– Revisions to the Residue Chemistry Crop Field Trial Requirements OECD Guideline 509 Crop Field Trial (September 2009) GLP Compliance: No deviations from regulatory requirements were reported which would

have an impact on the validity of the study. Acceptability: The study is considered scientifically acceptable.
Evaluator: Natalie Gaudreau (PMRA Canada)

EXECUTIVE SUMMARY

Eleven field trials for se thoxydim on blueberries were conducted in Canada and the United States encompassing North American Free Trade Agreement (NAFTA) Growing Regions 1A (3 trials in NS), 1 (1 trial in ME), 2 (3 trials in NC), 5A (3 trials in MI) and 12 (1 trial in OR) during th e 2008 growing season. Of these 11 field trials, 4 were conducted on lowbush blueberries and 7 were conducted on highbush blueberries. For the highbush blueberry trials, 2 were conducted at the same location using the same spray mixture ( i.e. Trial No. N C06 and NC07), therefore, these
are not distinct trials.

At each lowbush blueberry trial location, sethoxydim formulated as POAST ® Herbicide (emulsifiable concentrate containing 18% ai) was applied twice as a post

- emergent foliar
treatment at a rate of 0.476

- 0. 523 lbs ai/A ( 534

- 586 g ai/ha) for a total seasonal rate of 0.961

- 1. 019 lbs ai/A (1078

- 1142 g ai/ha)

. At each highbush blueb erry trial location, sethoxydim formulated as POAST® Herbicide (emulsifiable concentrate containing 18% ai) was applied twice as a broadcast application to the ground on each side of the blueberry row at a rate of
0.479

- 0.548 lbs ai/A (537

- 614 g ai/ha) for a total seasonal rate of 0.978

- 1.078 lbs ai/A (1096

- 1208 g ai/ha). An adjuvant or crop oil concentrate was added to the spray mixture for all applications. Blueberries were harvested at a preharvest interval (PHI) of 1 day

. In one lowbushSethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 2 of 8 

### blueberry tri al, samples were collected at different time intervals (PHIs of 0, 3, 7 and 10 days) to
monitor residue decline.

All samples were maintained frozen at the testing facility, during shipping to the laboratory

, and

were stored frozen until analysis

. The max imum storage interval for samples between harvest and analysis was 848 days (28.2 months)

. Residues of sethoxydim have been shown to be stable
in strawberries for up to 31 months under frozen conditions

. Adequate storage stability data are
therefore avai lable to support the storage conditions and intervals for samples in the current
trials.

Samples in the current study were analyzed using Method Version #36

, a GC/FPD method to determine residues of sethoxydim

. In this method, sethoxydim and its sulfide and sulfoxide metabolites are oxidized to sulfones, and the cyclohexene

- 1

- one ring is cleaved to two common
moieties: 3

- alkyl and 3

- alkyl

- 3

- hydroxy substituted pentanedioic acid. The acids are methylated to dimethyl 3

- [2

- (ethylsulfonyl)propyl]pentanedioate (DME) and dimethyl 3

- [2

- (ethylsulfonyl)propyl]3

- hydroxy pentanedioate (DME

- OH), which are the conversion products of the sethoxydim metabolites sethoxydim sulfoxide (MSO) and 5

- hydroxy sethoxydim sulfone (5

- OH

- MSO 2 

### ), respectively. Acceptable method valid ation and concurrent recoveries were reported for blueberry samples at fortification levels of 0.05 ppm , 0.50 ppm, 5.0 ppm and/or 15.0 ppm with the exception of one concurrent recovery at 67%, thus validating the method

. The limit of quantitation (LOQ) wa s determined to be 0.05 ppm for each analyte ( i.e. MSO and 5

- OH

- MSO 2 

### ) in blueberries which corresponds to a LOQ of 0.047 ppm for DME and 0.044 ppm
for DME

- OH (expressed as sethoxydim equivalents).

Individual sample (and per

- trial average) residues in lowb ush blueberries ranged from 0.164 ppm

to 8.92 ppm (3.34 ppm to 8.72 ppm) when treated at a total rate of 0.961

- 1.019 lbs ai/ha (1078

- 1142 g ai/ha) and sampled 1 day after treatment. Residue decline data show that residues of sethoxydim increased in lowbush blueberries from a 0 to 7

- day PHI and decreased from a 7 to
10

- day PHI.

Individual sample (and per

- trial average) residues in highbush blueberries ranged from <0.091 ppm to 0.204 ppm (<0.091 ppm to 0.184 ppm) when treated at a total rate of 0.978

- 1.078 lbs ai/ha (1096

- 1208 g ai/ha) and sampled 1 day after treatment.

I. MATERIALS AND METHOD S

A. MATERIALS

Table B.7.6.1.1

- 1. Nomenclature for Sethoxydim and Metabolites of Interest

. Common name Sethoxydim

CAS Name (±)

- 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one CAS no. 74051

- 80

- 2 Company experimental name BAS 562 05H Other synonyms (if applicable) None

Metabolite s Metabolites containing the cyclohexen

- 2

- one moiety ( i.e. MSO and 5

- OH

MSO 2 ; expressed as sethoxydim equivalents)Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 3 of 8 

### B. Study Design

1. Test Procedure

A total of 4 residue trials in/on lowbush blueberries and 7 residue trials in/on highbush
blueberries were conducted with an emulsifiable concentrate (Poast Herbicide, EPA Reg. No.
7969

- 58) during the 2008 growing season (Table B.7.6.1.1

- 2).

Table B.7.6.1.1

- 2. Trial Numbers and Geographical Locations.

Crop Region Total

1 2 3 4 5 6 7 8 9 10 11 12 13 14

Lowbush
blueberries 4

- - - - - - - - - - - - - 4

Highbush
blueberries - 3

- - 3

- - - - - - 1

- - 7



### Locations and detailed use patterns for the trials are provided in Table B.7.6.1.1

- 3.

Table B.7.6.1.1

- 3. Study Use Pattern. Location: City,
State /Province ; Year (Trial ID) * End

- use

Product/
Formulation ( % ai ) Method of Application/

Timing of Application Volume (gal/A) [L/ha] Rate per

Application (lbs ai/A) [g ai/ha] Retreatment

Interval (days) Total Rate

(lbs ai/A) [g ai/ha] Surfactant/

Adjuvant

LOWBUSH BLUEBERRIES

Trial No. NS01 Kentville, NS /
2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Foliar Broadcast/

Berries Formed 32.09 [300] 0.501

[562] - 1.006 [1128] Merge

Adjuvant 1% (v/v) 2. Foliar Broadcast/ 70% of ripe blueberries 32.35 [303] 0.505

[566] 12

Trial No. NS02 Rawdon, NS/ 2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Foliar Broadcast/

Berries turning blue 31.7 [297] 0.495

[555] - 0.989 [1109] Merge

Adjuvant 1% (v/v) 2. Foliar Broadcast/
Berries blue 31.64 [296] 0.494

[554] 14

Trial No. NS03 Debert, NS/ 2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Foliar Broadcast/

Berries blue in color 31.73 [297] 0.496

[556] - 1.019 [1142] Merge

Adjuvant 1% (v/v) 2. Foliar Broadcast/
Berries blue in color 33.47 [313] 0.523

[586] 14

Trial No. ME03 Jonesboro, ME/
2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Foliar Broadcast/

Fruiting 19.5 [182] 0.485

[544] - 0.961 [1078] Crop oil

concentrate 1.25% (v/v) 2. Foliar Broadcast/ Fruiting 19.1 [179] 0.476

[534] 14

HIGHBUSH BLUEBERRIES

Trial No. MI30 Holt, MI/ 2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 20 [187] 0.499

[559] - 0.978 [1096] Crop oil

concentrate 0.55% (v/v) 2. Broadcast to the ground / Fruiting 19.2 [180] 0.479

[537] 16

Trial No. MI31 Fennville, MI/
2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 20.2 [189] 0.505

[566] - 1.009 [1131] Crop oil

concentrate 0.58% (v/v) 2. Broadcast to the ground / Fruiting 20.2 [189] 0.504

[565] 14Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 4 of 8 Table B.7.6.1.1

- 3. Study Use Pattern. Location: City,
State /Province ; Year (Trial ID) * End

- use

Product/
Formulation ( % ai ) Method of Application/

Timing of Application Volume (gal/A) [L/ha] Rate per

Application (lbs ai/A) [g ai/ha] Retreatment

Interval (days) Total Rate

(lbs ai/A) [g ai/ha] Surfactant/

Adjuvant

Trial No. MI32 Benton Harbor, MI/
2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 19.7 [184] 0.492

[551] - 1.016 [1138] Crop oil

concentrate 0.61% (v/v) 2. Broadcast to the ground / Fruiting 21.0 [196] 0.524

[587] 13

Trial No. NC06 Castle Hayne, NC/
2008 ** POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 33.1 [310] 0.495

[555] - 0.991 [1111] Crop oil

concentrate 0.75% (v/v) 2. Broadcast to the ground / Fruiting 33.2 [311] 0.496

[556] 15

Trial No. NC07 Castle Hayne, NC/
2008 ** POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 33.0 [309] 0.494

[554] - 0.986 [1105] Crop oil

concentrate 0.75% (v/v) 2. Broadcast to the ground / Fruiting 32.9 [308] 0.492

[551] 15

Trial No. NC29 Castle Hayne, NC/
2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Fruiting 31.5 [295] 0.496

[556] - 0.993 [1113] Crop oil

concentrate 0.79% (v/v) 2. Broadcast to the ground / Fruiting 31.6 [296] 0.497

[557] 15

Trial No. OR19 Aurora, OR/ 2008 POAST ®

Herbicide
emulsifiable

concentrate (18%) 1. Broadcast to the ground /

Some blue fruit; mostly

green 31.8 [297] 0.530

[594] - 1.078 [1208] Crop oil

concentrate 0.84% (v/v)

2. Broadcast to the ground / Blue ripe berries present 32.9 [308] 0.548

[614] 13

* All trial Nos. have the prefix “09933.08

- “.
** These trials were conducted at the same location using the same spray mixture . Therefore these are not distinct trials.



### Lowbush blueberries and highbush blueberries were grown and maintained according to typical agricultural practices . Irrigation was used at trial No. NC06 , NC07, NC29 and OR19 . No unusual weather conditions were reported during the study.

Sample Handling and Preparation At each trial site, duplicate samples of blueberries were collected from the control plot and the treated plot one day after the last application. Samples were collected from at least 12 separate areas of each plot . In the highbu sh blueberry plots, the blueberries were collected by hand from all areas of the blueberry bush (high, low, exposed and sheltered by the foliage). In the lowbush blueberry plots, the berries were collected by raking the blueberries from a diagonal swath a cross the plot (the collected berries were exposed and sheltered by the foliage). Samples weighed approximately 2 lbs ( 0.9 kg). Collected samples were stored frozen ( ≤ 32°F / ≤ 0°C ) within 7 hours and 10 minutes of harvest. All samples were shipped froz en via ACDS freezer truck, except for trial No. ME03 which was shipped through Federal Express, to the NYSAES in Geneva, NY for extraction and analysis.

The samples were received frozen and in good condition at the analytical laboratory and held frozen (

- 21 ± 7oC) until ground. The blueberry samples were removed from the freezer for grinding and returned to frozen storage until used for fortification and/or analysis.Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 5 of 8 

### 2. Description of Analytical Procedures

Samples of highbush and lowbush blueberries w ere analyzed for residues of sethoxydim using
the working Analytical Method version #36 entitled “Residue Analysis of BAS 9052H and its Metabolites on blueberry by GC/FPD”

. This method is based on the reference Analytical Method No. 30 and addendums 30B, 30G or 30H, BASF Wyandotte Corporation, 1982

- 1985
entitled “Determination of BAS 9052H and its Metabolite Residues in Soybean Seed, Soybean Seed Process Fractions, Chicken Tissues, Beef Tissues, Milk and Eggs”. BASF Method 30, also known as BASF Method No. 181 (PMRA #1150979), was previously reviewed by the PMRA and deemed adequate as a data gathering method (Review of September 17, 1987). The limit of quantitation (LOQ) w as 0.047 ppm for DME and 0.044 ppm for DME

- OH

, each expressed as parent equivalents.

In this method, sethoxydim and its sulfide and sulfoxide metabolites are oxidized to sulfones, and the cyclohexene

- 1

- one ring is cleaved to two common moieties: 3

- alkyl a nd 3

- alkyl

- 3

- hydroxy substituted pentanedioic acid. The acids are methylated to dimethyl 3

- [2

- (ethylsulfonyl)propyl]pentanedioate (DME) and dimethyl 3

- [2

- (ethylsulfonyl)propyl]3

- hydroxy pentanedioate (DME

- OH), which are the conversion products of the setho xydim metabolites sethoxydim sulfoxide (MSO) and 5

- hydroxy sethoxydim sulfone (5

- OH

- MSO 2 

### ), respectively. Residues were presented in the laboratory analytical data sheets as DME and DME

- OH. The values
obtained for DME and DME

- OH were converted to sethoxydi m equivalents by multiplying by
1. 11 and 1. 05 , respectively.

Briefly, samples were blended with methanol for 5 minutes, evaporated, reconstituted in methanol and water (1:2, v:v) and precipitated with calcium hydroxide. After filtration, the filtrate wa s acidified with concentrated HCl and partitioned with methylene chloride three times. After evaporation of the solvent, the extract was oxidized with hydrogen peroxide. Excess hydrogen peroxide was removed with Catalase suspension, and evaporated to dry ness. The extract was methylated (esterified) with acidic methanol and again partitioned with methylene chloride. After evaporation to dryness, the extract was dissolved in acetone and analysed for DME and DME

- OH by GC/FPD operated in sulfur mode

. The l imit of quantitation (LOQ) was determined to be 0.05 ppm for each analyte ( i.e. MSO and 5

- OH

- MSO 2 

### ) which corresponds to a LOQ of 0.047 ppm for DME and 0.044 ppm for DME

- OH (expressed as sethoxydim equivalents).

II. RESULTS AND DISCUSSION

Method performance was evaluated during method validation and by use of concurrent recovery samples by fortifying blueberries at 0.05 ppm, 5.0 ppm and 15.0 ppm

. Twelve samples of
blueberries were fortified with MSO at 0.05 ppm and individual recoveries ra nged from 88 % to
120 % with a standard deviation of 10%

. Six samples of blueberries were fortified with MSO at 5.0 ppm and individual recoveries ranged from 72 % to 86 % with a standard devi ation of 6%. Three samples of blueberries were fortified with MSO a t 15.0 ppm and individual recoveries ranged from 67% to 73% with a standard deviation of 3%. Twelve samples of blueberries were fortified with 5

- OH

- MSO 2 

### at 0.05 ppm and individual recoveries ranged from 88 % to 112 % with
a standard deviation of 9%

. Six samples of blueberries were fortified with 5

- OH

- MSO 2 

### at 5.0Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 6 of 8 

### ppm and individual recoveries ranged from 74 % to 92 % with a standard devi ation of 7%. Three samples of blueberries were fortified with 5

- OH

- MSO 2 

### at 15.0 ppm and individual recoveries ranged from 73% to 80% with a standard deviation of 4%. With the exception of one concurrent recovery at 67%, a ll recoveries were within the acceptable range of 70% to 120%; therefore, the method was considered valid for the analysis of sethoxydim residues in blueberr ies matrices.
The fortification levels did bracket the measured residues.

The detector response was linear (coefficient of determination , r 2 

### ≥ 0.98812 for DME and r 2 

### ≥
0.98440 for DME

- OH ) within the range of 0.1

– 1.0 μg/mL. Representative chromatograms of control samples, fortified samples and treated samples were provided. The control chromatograms generally had no peaks of interest above th e chromatographic background. The fortified sample chromatograms contained only the analyte of interest, and pe aks were symmetrical and well de fined. Metabolites were expressed in parent equivalents

.

The field residue samples were stored frozen a maximum of 848 days (28.2 months) from harvest to analysis (Table B.7.6.1.1

- 5). A concurrent freezer storage stability study was not conducted. However, freezer storage stability data are on file for strawberries, a crop within the Berry and Small Fruit Crop Group 13

- 07 which indicate that residues of sethoxydim are stable for up to 31 months (PMRA # 2387981; Previously reviewed under review of February 11, 1993).

Table B.7.6.1.1

- 5. Summary of Storage Conditions

Matrix (RAC or Extract) Storage Temperature ( oF / °C) Actual Storage Duration (months ) Interval of Demonstrated Storage Stability ( months)

Blueberries ≤ 32 / ≤ 0 28.2 Data are on file for strawberries, a crop within the Berry and Small Fruit Crop Group 13

- 07 indicating that residues of sethoxydim are stable for up to 31 months of frozen storage (PMRA #2387981; Review of F ebruar y 11, 1993).



### The results from these trials showed that when harvested 1 day after the last of 2 applications at a seasonal rate of 0.961

- 1.078 lbs ai/A (1078

- 1208 g ai/ha), total combined residues of sethoxydim equivalents in lowbush blueberries ranged from <0.164 ppm to 8.92 ppm and residues in highbush blueberries ranged from <0.091 ppm to 0.204 ppm (Tables B.7.6.1.1

- 6 and B.7.6.1.1

- 7).

In the residue decline trials, mean residue level increased from 7.89 ppm to 10.48 ppm in
lowbush blueberrie s between PHIs of 0 and 7 days and decreased to 9.25 ppm at a PHI of 10 days.Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 7 of 8 Table B.7.6.1.1

- 6. Residue Data from Blueberry Field Trials with Sethoxydim Location: City,
State /Province ; Year (Trial ID) * Region Crop Variety Matrix End

- Use

Product Rate

(lbs ai/A) [kg ai/ha] PHI

(days) Residues 1 (ppm)

DME DME

- OH Total 2 (per

- trial average)

LOWBUSH BLUEBERRIES

Trial No. NS01 Kentville, NS/
2008

1A Wild
C lones Berries POAST ®

Herbicide 1.006

[1128] 0 7.8, 7.3 0.32, 0.36 8.12, 7.66 (7.89)

1 7.4, 7.6 0.42, 0.40 7.82, 8.0 (7.91)

3 9.1, 10 0.46, 0.46 9.56, 10.46 (10.01)

7 10, 9.5 0.76, 0.70 10.76, 10.2 (10.48)

10 8.6, 8.4 0.67, 0.82 9.27, 9.22 (9.25)

Trial No. NS02 Rawdon, NS/
2008 1A Wild
C lones Berries POAST ®

Herbicide 0.989

[1109] 1 6.9, 7.4 0.35, 0.40 7.25, 7.8 (7.53)

Trial No. NS03 Debert, NS/ 2008 1A Wild
C lones Berries POAST ®

Herbicide 1.019

[1142] 1 8.5, 8.1 0.42, 0.42 8.92, 8.52 (8.72)

Trial No. ME03 Jonesboro, ME/
2008 1 Varies

Wild
Plants Berries POAST ®

Herbicide 0.961

[1078] 1 6.3, 0.12 0.21, <0.044 6.51, <0.164 (3.34)

HIGHBUSH BLUEBERRIES

Trial No. MI30 Holt, MI/ 2008 5A Jersey Berries POAST ®
Herbicide 0.978

[1096] 1 <0.047,

<0.047 <0.044,

<0.044 <0.091,

<0.091 (<0.091)

Trial No. MI31 Fennville, MI/
2008 5A Rubel Berries POAST ®
Herbicide 1.009

[1131] 1 0.048, 0.069 <0.044,
<0.044 0.092, 0.113

(0.103)

Trial No. MI32 Benton Harbor,
MI/ 2008 5A Blue Crop Berries POAST ®

Herbicide 1.016

[1138] 1 <0.047,

<0.047 <0.044,

<0.044 <0.091,

<0.091 (<0.091)

Trial No. NC06 Castle Hayne,
NC/ 2008** 2 Croatan Berries POAST®
Herbicide 0.991

[1111] 1 <0.047,

<0.047 <0.047,
<0.047 <0.044,

<0.044 <0.044,
<0.044 <0.091,

<0.091

<0.091,
<0.091 (<0.091) Trial No. NC07 Castle Hayne,
NC/ 2008** 2 Duplin Berries POAST®
Herbicide 0.986

[1105] 1

Trial No. NC29 Castle Hayne,
NC/ 2008 2 Summit Berries POAST ®
Herbicide 0.993

[1113] 1 0.16, 0.12 <0.044,
<0.044 0.204, 0.164

(0.184)

Trial No. OR19 Aurora, OR/ 2008 12 Blue Crop Berries POAST ®

Herbicide 1.078

[1208] 1 <0.047,

<0.047 <0.044,

<0.044 <0.091,

<0.091 (<0.091)

1 Expressed as parent equivalents.

2 Total = DME + DME

- OH (expressed as sethoxydim equivalents) * All trial Nos. have the prefix “09933.08

- “.
** These trials were conducted at the same location using the same spray mixture . Therefore these are not distinct trials.Sethoxydim (SOD)/BASF Canada Inc. (BAZ)

EPA MRID #: 49257701 /DP No. D422744

PMRA # of document: 2432176 Page 8 of 8 Table B.7.6.1.1

- 7. Summary of Residues from Blueberry Field Trials with Sethoxydim

Crop Matrix Total Application

Rate (lbs ai/A) [g ai/ha] PHI

(days) n Residues 1 (ppm)

Min. 2 Max. 2 LAFT 3 HAFT 3 Median 3 Mean 3 SD 3

LOWBUSH BLUEBERRIES

Lowbush
blueberries 0.961

- 1.019

[1078

- 1142] 1 4 0.164 8.92 3.34 8.72 7.72 6.88 2.41

HIGHBUSH BLUEBERRIES Highbush
blueberries 0.978

- 1.078

[1096

- 1208] 1 7 0.091 0.204 0.091 0.184 0.091 0.106 0.035

1 Combined residues of DME and DME

- OH expressed as sethoxydim equivalents

. 2 Values based on total number of samples.

3 Values based on per

- trial averages. LAFT = lowest average field trial, HAFT = highest average field trial, SD = standard deviation. For computation of the LAFT, HAFT, median, mean, and standard deviation, values < LOQ are assumed to be at the
the LOQ (0.091 ppm; combined LOQs of DME and DME

- OH expressed as parent equivalents).
n = number of field trials.



### III. CONCLUSIONS

The blueberry field trials are considered scientifically acceptable

. The results of the study showed that following a total application rate of 0.961

- 1.019 lbs ai/A (1078

- 1142 g ai/ha) in lowbush blueberry samples collected at a PHI of 1 day

, total combined residues of sethoxydim equivalents ranged from 0.164 ppm to 8.92 ppm. A decline study indicates that the level of
combin ed residues of sethoxydim equivalents in lowbush blueberries increase up to a PHI of 7 days and decrease by a PHI of 10 days

.

Following a total application rate of 0.978

- 1.078 lbs ai/A (1096

- 1208 g ai/ha) in highbush blueberry samples collected at a PHI of 1 day, total combined residues of sethoxydim equivalents ranged from <0.091 ppm to 0.204 ppm. The residue decline behaviour was not assessed in the highbush blueberry trials.

A n acceptable method was used for residue quantitation and a dequate storage stability data are available to support sample storage durations and conditions.

REFERENCES

PMRA # 1150979. Beutel , P. (1981) “BAS 9052H: GC Determination, Total method including MU type compounds determination”, Method No. 181. Unpublished study prepared by BASF Aktiengesellschaft, 136 pages.

PMRA # 2387981. Zehr, R. D. (1987) “Magnitude of the Residue of Sethoxydim and Metabolites in Blueberries” Registration Document #BASF: 87/5084. Unpublished study prepared by BASF Corporation Chemicals Division, Parsippany, NJ, 94 pages. ( NOTE: This study includes the freezer storage stability data for sethoxydim in/on strawber ries)Sethoxydim / PC Code 121 00 1 / lnterregional Research Project No

. 4

DACO 7 .4

. 1 17 .4

. 2 / 0CSPP 860.1500 / 0ECD IIA 6.3.1

, 6

. 3.2

, 6.3. 3 and lilA 8.3.1, 8 .3 .2

, 8.3

. 3 Crop Field Trial

- Fine Fescue Grass (grown for seed)



### Primary · Evaluator Date: 06 / 05 / 20 14

Versar, Inc.

_;.-...,.**~** 

### Approved by 

### (

_ / -;t-, l

## A**~** 

### Date: 11119 / 20 14

Peter Savoia, Chemist, OCSPP

- HED-RAB V

Note: This Da ta Evaluation Record (DER) was originally prepared under contract by Versar, In c

. (6850 Versar Center, Sp ringfield

, VA 22151; submitted 6 /5/ 14 ). The DER has been reviewed by HED and r ev i sed to reflect

current Office of Pesticide Programs (OPP) policies

.



### STUDY REPORT:



### 49257702 Barney, W. ; Homa

, K. (2009) Sethoxydim: Magnitude of the Residue on Fine Fescue

Grasses. Proj ect Numbers: A4873 and A4873.07-NYR05. Unpublished study prepared by

Interr eg ional Research Project No. 4 and Cornell University. 355 p.

EXECUTIVE SUMMARY:



### The Interregional Research Project No.4 (IR-4) has submitted field trial data for sethoxydim on fine fescue grass. Five grass field trials were conducted in the U nited States during the 2007 growing season in the North American Free Trade Agreement (NAFTA) Zones 11 (WA ; 2 tr ials )

and 12 (OR; 3 trials). Careful examination ofthe field trial records indicates that the two WA

trials were conducted at the same location s with very few differences in st udy desi g n ; for this

reason HED has det ermi ned these trials constitute a single trial with replicate samples for

purposes of 860.1500 data requirements. The three OR trials were also cond uct ed at the same location; howe ver, H ED has concluded that the se may be considered independent due

differences in the grass variety used.

Each trial consisted of one untr ea ted plot and one treated plot. At each trial location

, the treated plot received two foliar broadcast applications of a 1.5 lb ail gal emulsifiable conce ntrat e (EC)

formulation of sethoxydim (POAS T ® 1. 5 EC) at 0.465-0.498 l b 

## a i l A/application for a total

seasonal rate of0.936-0.973 lb ai/A. Applications were made at 30

- to 44-day retreatment
intervals (RTis) using ground equ ipm ent in spray vo lum es of 14 .9-20.3 ga l / A. A crop oil

concentrate (COC) was a dd ed to each spray mixture. Following the second application, samples

were harvested from all trials at preharvest intervals (PHis) of 13-14 day s for grass forage and

21-28 days for grass hay. Hay samples were allowed to dry in an e nclo sed area for 3 -7 days prior to collection.

Samples of grass forage and hay we r e analyzed for residues of sethoxydim and its metabolites using a gas chromatography method with flame photometric detection in the sulfur mode (GC/FPD) adapted from the accepted enforcement analytical method. With this method, sethoxydim and its metabolites are determined as 3-(2 (et h ylsulfo n yl)propy l]-p entane di oic acid

DP # 422744 / MRID No

. 49257702 Page I of 12Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 2 of 12 

### dimethyl ester (DME) and 3

- [2

- (ethylsulfonyl)propyl]

- 3

- hydroxype ntanedioic acid dimethyl ester (DME

- OH) following oxidation and derivatization, and residues are reported in terms of sethoxydim equivalents using conversion factors . The limit of quantitation (LOQ), determined as the lowest level of method validation, (L LMV) was 0.042 ppm for all analytes and sample
matrices

. The method is adequate for data collection based on acceptable concurrent recovery data. Because sethoxydim contains a labile thioether, it readily oxidizes to 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethyls ulfinyl)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one (MSO) and to 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylsulfonyl)propyl]

- 3,5

- dihydroxy

- 2

- cyclohexen

- 1

- one (5

- OH

MSO 2 

### ), so these sulfoxy analytes were used for sample fortification. The fortification levels
used in th e concurrent method recoveries were adequate to bracket expected residue levels.

S amples of grass forage and hay were stored frozen (

- 21 ± 7 °C) from collection to extraction for
108

- 123 days ( 3.6

- 4.0 months) and 172

- 272 days (5. 7

- 8.9 months), respectively

. All samples

w ere analyzed within 2

- 4 days of extraction. Storage stability data generated concurrently with the field trial study demonstrate that residues of sethoxydim, determined as DME and DME

- OH

, were stable in/on samples of grass fora ge and hay (fortified with MSO and 5

- OH

- MSO 2 

### ) stored frozen for up to 174

- 193 and 277

- 281 days, respectively

. These data are acceptable to support the storage conditions and durations of samples from the submitted grass field trials; however, storage stab ility studies should always include a 0

- day sampling interval to establish the residue levels present at the time samples are placed into storage [see OCSPP 860.1380(d)(6)(i)].

Following two foliar broadcast applications of the 1.5 lb ai/gal EC formulatio n of sethoxydim at
a total rate of 0.936

- 0.973 lb ai/A, residues (and per trial averages) of sethoxydim equivalents, (determined as DME, DME

- OH, and combined residues; respectively, were: 1.0

- 2.8 (1. 4

- 2.7),
0.21

- 0.42 (0.22

- 0.34), and 1.24

- 3.16 (1.65

- 3.04) ppm, in/on fine fescue grass forage harvested at
a 13

- to 14

- day PHI; and 0.48

- 1.3 (0.65

- 1.1), 0.14

- 0.40 (0.15

- 0.35), and 0.75

- 1.45 (0.98

- 1.26),
in / on fine fescue grass hay harvested at a 21

- to 28

- day PHI.

Residue decline data were not submitted

.

STUDY/ WAIVER ACCEPTABILITY/DEFICIENCIES/CLARIFICATIONS :

Under the conditions and parameters used in the study, the field trial residue data are classified as scientifically acceptable. The acceptability of this study for regulatory purposes is addressed
in the forthcoming U.S. EPA Residue Chemistry Summary Document [DP No. 4 22744 ].

COMPLIANCE :

Signed and dated Good Laboratory Practice (GLP), Quality Assurance, and Data Confidentiality statements were provided. No deviations from regulatory requirements were reported which would have an impact on the validity of the study.Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 3 of 12 

### A. BACKGROUND INFORMATION

Sethoxydim is a selective, systemic, postemergence herbicide used for the control of annual and perennial grass weeds in broadleaf crops. S ethoxydim is a member of the cyclohexanedione class of pesticides. Other members of this class include cycloxydim, clethodim, and tralkoxydim. The sethoxydim nomenclature is summarized in Table A.1 and the physicochemical properties are summarized in Tab le A.2.

T ABLE A. 1. Sethoxydim Nomenclature

. Chemical structure

Common name S ethoxydim
Company experimental name BAS 9052 H or BAS 562 05H

IUPAC name (5 RS )

- 2

- [( EZ )

- 1

- (ethoxyimino)butyl]

- 5

- [(2 RS )

- 2

- (ethylthio)propyl]

- 3

- hydroxycyclohex

- 2

-

en

- 1

- one

CAS name 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylthio)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one CAS registry number 74051

- 80

- 2

End

- use product (EP) 1.5 lb ai/gal EC formulation (Poast® Herbicide; EPA Reg. No. 7969

- 58)

Chemical structure of 2

- cyclohexen

- 1

- one metabolites

Derivatized residues determined by the analytical method

Common and chemical names DME; 3

- [2

- (ethylsulfonyl)propyl]

- pentanedioic acid dimethyl ester DME

- OH; 3

- [2

- (ethylsulfonyl)propyl]

- 3

- hydroxypentanedioic acid dimethyl ester

Metabolites used for sample
fortification 1

Common and chemical names MSO; 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylsulfinyl)propyl]

- 3

- hydroxy

- 2

- cyclohexen

- 1

- one 5

- OH

- MSO 2 ; 2

- [1

- (ethoxyimino)butyl]

- 5

- [2

- (ethylsulfonyl)propyl]

- 3,5

- dihydroxy

- 2

- cyclohexen

- 1

- oneSethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 4 of 12 1 Sethoxydim is readily oxidized to MSO and 5

- OH

- MSO 2 in air; therefore, these metabolites are used for sample fortification.

TABLE A. 2. Physicochemical Properties of Sethoxydim

Parameter Value Reference

Boiling point/range >130 °C at 6 x 10

- 1 mm Hg HED Chemistry Chapter of the Sethoxydim RED, 6/22/05, W.

Donovan pH 3.95 at 20 °C
Density 1.058 g/cm 3 at 20 °C (specific gravity)
Water solubility 257 ppm at pH 5, 4390 ppm at pH 7 (25 °C)
Solvent solubility Freely soluble (>10 3 g/100 mL) in organic solvents (methanol, n

- octanol, ethyl acetate, n

- hexane, toluene, and xylene) at 20 °C

Vapor pressure 1.6 x 10

- 7 mm Hg at 25 °C
Dissociation constant, pK a 4.6 at pH 4.5 and 25 °C
Octanol/water partition coefficient, Log(K OW ) K OW = 3.26 x 10 3 at pH 5; 45.1 at pH 7; and 0.93 at pH 9
UV/visible absorption spectrum Not available



### B. EXPERIMENTAL DESIGN

B.1. Study Site Information

Five grass field trials were conducted in the United States during the 2007 growing season in the
NAFTA Zones 11 (WA; 2 trials) and 12 (OR; 3 trials). As detailed below, HED has determined
that the two WA trial s are replicates and therefore constitute a single trial with replicate sa mples for purposes of 860.1500 data requirements. HED has further concluded that the OR trials may be considered independent due differences in the grass variety

. The replicate trial determination for the study is summarized in the table below.

Independ ent Trial Determination 1

Trial Nos. Differences Decision

- WA24 and

- WA25 (fine fescue grass, forage and hay) PHI: 13 days for forage; 28 and 22 days for hay

RTI: 31 and 30 days Harvest Timing: forage was harvested pre

- boot stage (6 to 8 inches tall) for trial

– WA24 and the vegetative, pre

- boot stage (8 to 10 inches tall) for
trial

– WA25; hay samples, were harvested at the early seed head for both trials.
Residues: comparable
No other difference s were found. Replicates

- OR18,

- OR 19, and

– OR20 Variety: Hard fescue (Predator) vs. Creeping red fescue (Razor) vs. Chewing Fine Fescue (Shadow II)
Residues: ~2x higher in Trial

– OR19 than in Trials

– OR18 and

– OR20 Independent due to variety

1 All assessments are based on the replicate trial guidance presented in draft memo 568 _Criteria for Independence of Trials 04/23/2013 (EPA and PMRA).Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 5 of 12 

### Each trial consisted of one untreated plot and one treated plot. At each trial location, the treated

p lot received a two foliar broadcast applications of a 1.5 lb ai/gal EC formulation of sethoxydim (POAST® 1.5 EC) at 0.465

- 0.498 lb ai/A/application for a total seasonal rate of 0.936

- 0.973 lb ai/A. Applications were made at 30

- 44

- day RTIs using ground eq uipment in spray volumes of
14.9

- 20.3 gal/A. A COC was added to the foliar spray mixture for each trial . Samples of grass forage and hay were harvested from all trials at preharvest intervals (PHIs) of 13

- 28 days following the second application. Hay sa mples were allowed to dry for 3

- 7 days prior to
collection

The petitioner stated that agronomic practices typical of the trial locations were used for growing

crops. Maintenance pesticides and fertilizers were used as needed to produce a commercial quali ty crop. Minimum and maximum temperatures and total monthly precipitation were provided, as well as the historical averages

. Irrigation was used to supplement rainfall as needed.
Weather conditions at all field locations were generally considered normal

. However, at the OR
trials , there was an unusually cold and wet spring that delayed crop maturity until later in the

year. The petitioner indicated that prior to harvest, the crop s had matured as normal.

Trial conditions are presented in Table B.1.1. The study use pattern is presented in Table B.1.2, and the crop varieties grown are identified in Table C.3.

TABLE B.1.1

. Trial Site Conditions

.

Trial Identification: City, State; Year (Trial No.) Soil characteristics 1

Type %OM pH CEC ( meq/ 100 g )

Prosser

, W A ; 20 07 (

- WA24 ) Silt l oam 1.25 7.4 12.7

Prosser, WA; 2007 (

- WA2 5 ) Silt loam 1.25 7.4 12.7

Silverton

, OR ; 20 07 (

- OR18 ) Silty c lay l oam 3.0

- 6.0 4.5

- 6.5 10

- 25

Silverton, OR; 2007 (

- OR1 9 ) Silty clay loam 2.0

- 6.0 5.6

- 6.5 15

- 30

Silverton, OR; 2007 (

- OR 20 ) Silty clay loam 3.0

- 8.0 5.1

- 6.0 15

- 25

1 OM = organic matter; CEC = cation

- exchange capacity

TABLE B.1.2. Study Use Pattern.

Location ( C ity

, State; Year )
Trial ID 1 E P 2 Application Information Tank Mix/ Adjuvants 4 Method; Timing Volume ( gal/A ) Rate

( lb ai/ A ) RTI 3

(days) Total Rate

( l b a i / A )

Prosser, WA; 2007 (

- WA24) 1.5 lb

ai/gal EC 1. Foliar broadcast ; s emi

- dormant 19.6 0.467

- 0.939 COC

2. Foliar broadcast ; v egetative 19.6 0.472 31

Prosser, WA; 2007 (

- WA25) 1.5 lb

ai/gal EC 1. Foliar broadcast; s emi

- dormant 14.9 0.471

- 0.936 COC

2. Foliar broadcast; v egetative 20.3 0.465 30

Silverton, OR; 2007 (

- OR18) 1.5 lb

ai/gal EC 1. Foliar broadcast; semi

- dormant 15.1 0.475

- 0.973 COC

2 . Foliar broadcast; semi

- dormant 15.8 0.498 44Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 6 of 12 TABLE B.1.2. Study Use Pattern.

Location ( C ity

, State; Year )
Trial ID 1 E P 2 Application Information Tank Mix/ Adjuvants 4 Method; Timing Volume ( gal/A ) Rate

( lb ai/ A ) RTI 3

(days) Total Rate

( l b a i / A )

Silverton, OR; 2007 (

- OR19) 1.5 lb

ai/gal EC 1. Foliar broadcast; semi

- dormant 15.6 0.487

- 0.954 COC

2 . Foliar broadcast; semi

- dormant 14.9 0.467 44

Silverton, OR; 2007 (

- OR 20 ) 1.5 lb

ai/gal EC 1. Foliar broadcast; semi

- dormant 17.1 0.475

- 0.946 COC

2 . Foliar broadcast; semi

- dormant 16.9 0.471 44

1 HED has concluded that Trials

- WA24 and

- W A2 5 constitute a single trial with replicate samples for purposes of 860.1500 data requirements.

2 EP = End

- use Product; a 1 .5 lb ai/gal emulsifiable concentrate ( E C) formulation (POAST® 1.5 EC).

3 RTI = Retreatment Interval.

4 COC = C rop oil concentrate.

TABLE B.1.3. Trial Numbers and Geographical Locations

. NAFTA Growing Zones Grass (grown for seed)

Submitted Requested 1

Canada U.S.

1

-- -- --
1A

-- -- --
2

-- -- --
3

-- -- --
4

-- -- --
5

-- -- --
5A

-- -- --
5B

-- -- --
6

-- -- --
7

-- -- --
7A

-- -- --
8

-- -- --
9

-- -- --
10

-- -- --
11 1 2

-- --
12 3

-- --
13

-- -- --
14

-- -- --
15

-- -- --
16

-- -- --
17

-- -- --
18

-- -- --
19

-- -- --
20

-- -- --
21

-- -- --Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 7 of 12 TABLE B.1.3. Trial Numbers and Geographical Locations

. NAFTA Growing Zones Grass (grown for seed)

Submitted Requested 1

Canada U.S.

Total 4 5/8

1 In accordance with OCSPP 860.1000 and 860.1500, the following crop field trials are recommended for grasses grown for seed : for use in the Pacific Northwest

- five trials on representative varieties conducted on grass forage and hay, with two trials in Zone
11 and three trials in Zone 12 ; or for use in the U.S.

- eight trials on representative varieties conducted on grass forage and hay,
with two trials in Zone 11 , three tr ials in Zone 12 , and three trials in Zone 5 (refer to Draft Memo

, dated 9/30/00, Additional Guidance on the Crop

– ‘Grasses Grown for Seed’, Grasses Grown for Seed Policy Team

, P. Errico, et al )

. 2 HED has concluded that two trials conducted in WA (Zone 1 1 ) are replicate trials for purposes of 860.1500 data requirements.



### B.2. Sample Handling and Preparation

Duplicate control and duplicate treated samples were harvested from all trials following the second application at PHIs of 13

- 14 days for forage and 21

- 28 days for hay

. A minimum of two pounds of fine fescue forage was collected per sample. Forage was harvested in the 6

- 10 inch to boot stage, pre

- boot stage (6

- 8 inches tall), or vegetative, pre

- boot stage (8

- 10 inches tall). Hay

was harvested at early seed head. Hay samples were allowed to dry for 3

- 7 days in an enclosed

area prior to collection of a minimum of one pound per sample

. Samples of grass forage and hay were placed in frozen storage at the field sites within ~ 4 hours of c ollection.

All samples were shipped by ACDS freezer truck w ithin 4

- 57 days of collection to the analytical laboratory, New York State Agricultural Experiment Station (NYSAES; Geneva, NY) for residue analysis. Samples were maintained frozen (

- 21 ± 7 ° C) at the analytical laboratory prior to homogenization and analysis. In preparation for analysis, samples were homogenized in the presence of dry ice.

B.3. Analytical Methodology

Grass forage and hay s amples were analyzed for residues of s ethoxydim using the Cornell Analytical Laboratory Method titled “Residue Analysis of BAS 9052H (Sethoxydim) and Its Metabolites on Fine Fescue Grasses (forage and hay) by GC/FPD Detection in Sulfur Mode.
Version #35 and 35A .”

Briefly, residues were extracted wi th methanol, evaporated, reconstituted, and precipitated with calcium hydroxide. After filtration, the extract was acidified and then partitioned four times with dichloromethane (DCM)

. Sethoxydim and its metabolites were oxidized with hydrogen peroxide

a t reflux, and then esterified with acidic methanol to DME and DME

- OH . The derivatives were partitioned into DCM, evaporated to dryness, redissolved in acetone, and determined by GC /FPD in the sulfur mode. Residues are expressed as sethoxydim using molecu lar weight conversion
factors of 1.11x for DME and 1.05x for DME

- OH.Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 8 of 12 

### Because sethoxydim is very readily oxidized to MSO and 5

- OH

- MSO2, samples of untreated grass forage and hay were fortified with MSO and 5

- OH

- MSO 2 

### to generate concurrent recovery and stor age stability data. Recoveries are expressed as DME and DME

- OH using molecular weight conversion factors of 0.85x and 0.83x. The LOQ (determined as the LLMV) was 0.042 ppm each for MSO and 5

- OH

- MSO 2 

### . We note that the petitioner also presented calculated values for the LOD and LOQ based on the recoveries obtained at the 0.042

- ppm fortification
level. The calculated LOD and LOQ for DME and DME

- OH in fine fescue grass forage were calculated to be 0.007

, 0.021

, 0.005 , and 0.014 ppm , respectively

. The calcu lated LOD and LOQ
for DME and DME

- OH in fine fescue grass hay were calculated to be 0.013

, 0.038

, 0.004 , and 0.011 ppm

.

The method was validated prior to and in conjunction with the analysis of the field trial samples.

C. RESULTS AND DISCUSSION

Sample storage conditions and durations are summarized in Table C.2.1. Samples of grass forage and hay were stored frozen (

- 21 ± 7 °C) from collection to extraction for 108

- 123 days (3.6

- 4.0 months) and 172

- 272 days (5. 7

- 8.9 months), respectively. Hay sa mples were allowed to dry in an enclosed area for 3

- 7 days prior to collection. All samples were analyzed within 2

- 4 days of extraction. To support the sample storage intervals, a concurrent storage stability study
was conducted with the field trial st udy; the results are presented in Table C.2.2. The data demonstrate that residues of sethoxydim, determined as DME and DME

- OH were stable in/on samples of grass forage and hay (fortified with MSO and 5

- OH

- MSO 2 

### ) stored frozen for up to
174

- 193 and 277

- 281 days; no 0

- day data were provided. These data are acceptable to support the storage conditions and durations of samples from the submitted field trials; however, storage stability studies should always include a 0

- day sampling interval to establish the re sidue levels present at the time samples are placed into storage [see O CS PP 860.1380(d)(6)(i)].

Concurrent method recovery data for the GC/FPD method are presented in Table C.1. Grass forage and hay samples were fortified at 0.0 42

- 4

. 2 ppm with MSO and 5

- OH

- MSO 2



### . The method was adequate for data collection based on acceptable concurrent recovery data.
Recoveries were generally within the acceptable range of 70

- 120%. T he method is considered adequate based on concurrent recovery data. The fortificatio n levels used in concurrent method recovery were adequate to bracket expected residue levels. A pparent residues of DME and

DME

- OH were below the LOQ in/on all samples of untreated grass forage and hay

.

Residue data from the grass field trials are reporte d in Table C.3, and a summary of residue data is presented in Table C.4

. Following two foliar broadcast applications of the 1.5 lb ai/gal EC formulation of sethoxydim at a total rate of 0.936

- 0.973 lb ai/A, residues (and per trial averages) of sethoxydim equivalents, (determined as DME, DME

- OH, and combined residues; respectively, were: 1.0

- 2.8 (1. 4

- 2.7), 0.21

- 0.42 (0.22

- 0.34), and 1.24

- 3.16 (1.65

- 3.04) ppm, in/on fine fescue grass forage harvested at a 13

- to 14

- day PHI; and 0.48

- 1.3 (0.65

- 1.1), 0.14

- 0.40Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 9 of 12 

### (0.15

- 0.35), and 0.75

- 1.45 (0.98

- 1.26), in / on fine fescue grass hay harvested at a 21

- to 28

- day

PHI.

Residue decline data were not submitted.

T ABLE C.1. Summary of Method Validation and Concurrent Recoveries of Sethoxydim Metabolites

from Fine Fescue Grass. 1

Matrix Analyte Spike
Level (ppm) Sample

Size (n) Recoveries (%) Mean ± Std. Dev. (%) 2

Method Validation

Grass, forage DME 0.042 4 90, 95, 95, 100 95 ± 4.1

0.42 4 81, 81, 86, 105 88 ± 11.4

4.2 4 76, 88, 90, 93 87 ± 7.5

DME

- OH 0.042 4 95, 95, 100, 100 98 ± 2.9

0.42 4 69, 71, 76, 88 76 ± 8.5

4.2 4 71, 88, 90, 90 85 ± 9.2

Grass, hay DME 0.042 9 76, 76, 78, 81, 81, 93, 95, 95, 105 87 ± 10.5

0.42 3 95, 95, 98 96 ± 1. 7

4.2 3 81, 81, 86 83 ± 2.9

DME

- OH 0.042 9 71, 74, 76, 76, 76, 78, 78, 81, 81 77 ± 3.2

0.42 3 95, 95, 98 96 ± 1.7

4.2 3 71, 71, 76 73 ± 2.9

Concurrent Recovery

Grass, forage DME 0.042 3 100, 105, 105 103 ± 2.9

0.42 1 100 100

4.2 1 86 86

DME

- OH 0.042 3 90, 95, 100 95 ± 5.0

0.42 1 90 90

4.2 1 81 81
Grass, hay DME 0.42 3 98, 105, 107 103 ± 4.7

4.2 2 76, 83 80

DME

- OH 0.42 3 81, 88, 95 88 ± 7.0

4.2 2 69, 74 72

1 Samples were fortified with MSO and 5

- OH

- MSO 2 ; r ecoveries are expressed as DME and DME

- OH using molecular weight
conversion factors of 0.85 x and 0.83 x.

2 Standard deviation is not calculated for sample sizes <3Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 10 of 12 TABLE C.2. 1. Summary of Storage Conditions

. Matrix Analyte Storage Temperature (°C) Actual Storage Duration 1 Limit of Demonstrated Storage Stability 2

Grass, forage DME

- 2 1 ± 7 108

- 123 days ( 3.6

- 4.0 months) 174

- 193 days (5.7

- 6.3 months) DME

- OH

Grass, hay DME 172

- 272 days (5. 7

- 8.9 months) 277

- 281 days ( 9

. 1

- 9.2 months) DME

- OH

1 Interval from harvest to extraction

. Samples were analyzed within 2

- 4 days of extraction.

2 Based on concurrent storage stability study. See Table C.2.2.

TABLE C.2.2. Stability of Sethoxydim Metabolites in Frozen Fine Fescue Grass

. 1

Analyte Spike

Level (ppm) Storage

interval 2 (days) Fresh Fortification

Recoveries (%) [Average] Recovered

Residues (ppm) Mean

Recovered
Residues (ppm) Mean

Recovery (%) Corrected %

recovery 3

Grass forage

DME 0.42 174

- 193 100, 71, 81 [84] 0.36, 0.34, 0.32 0.34 81 96

DME

- OH 0.42 174

- 193 90, 71, 76 [79] 0.32, 0.30, 0.32 0.31 74 94
Grass hay

DME 0.42 277

- 281 95, 93, 100 [96] 0.3 8 , 0.3 9 , 0.3 4 0.37 88 92

DME

- OH 0.42 277

- 281 86, 90, 100 [92] 0.3 6 , 0.39, 0.3 5 0.37 88 96

1 Samples were fortified with MSO and 5

- OH

- MSO 2 ; r ecoveries are expressed as DME and DME

- OH using molecular weight
conversion factors of 0.85 x and 0.83 x.

2 Interval from fortification to extraction. Samples were analyzed 2

- 4 days after extraction.

3 Corrected for mean recovery of freshly fortified samplesSethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 11 of 12 TABLE C.3. Residue Data f rom Grass Field Trials with Sethoxydim

. Trial ID (City, State; Year) 1 Zone Grass Variety Commodity Total Rate (lb ai/A) PHI

(days) 2 Residues (ppm ) 3 [Average]

DME 4 DME

- OH 4 Combined

Prosser, WA; 2007 (

- WA24 and

- WA25) 11 Fine fescue;
Festuca ovina Forage 0.936

- 0.939 13 1.2

, 1.0

, 1.6

,

1.7

, [1. 4 ] 0.31

, 0.24

,

0.40

, 0.42 [0.34] 1.51

, 1.24

,

2.00

, 2.12 [1.72]

Hay 22

- 28 (4) 0.48

, 0.64

, 0.84

, 0.64 [ 0.65 ] 0.27

, 0.36

,

0.38

, 0.29 [0.33] 0.75

, 1.00

,

1.22

, 0.93 [0.98]

Silverton, OR; 2007 (

- OR18) 12 Hard fescue;
Predator Forage 0.973 14 1.6

, 1.2 [ 1.4] 0.26

, 0.23

[ 0.25] 1.86

, 1.43

[ 1.65]

Hay 28 (3) 0.81

, 0.76

[0.79] 0.27

, 0.28

[0.28] 1.08

, 1.04

[1.06]

Silverton, OR; 2007 (

- OR1 9 ) 12 Creeping red fescue;

Razor Forage 0.954 14 2.8

, 2.6 [2.7] 0.36

, 0.32

[0.34] 3.16

, 2.92

[3.04]

Hay 21 (7) 1.3

, 0.92

[1.1] 0.15

, 0.14

[0.15] 1.45

, 1.06

[1.26]

Silverton, OR; 2007 (

- OR 20 ) 12 Chewing fine fescue;
Shadow II Forage 0.946 14 1.5

, 1.6 [1. 6 ] 0.21

, 0.22

[0.22] 1.71

, 1.82

[1.77]

Hay 28 (3) 0.80

, 1.0

[0.90] 0.30

, 0.40

[0.35] 1.10

, 1.40

[1.25]

1 HED has concluded that Trials

- WA 2 4 and

- W A2 5 constitute a single trial with replicate samples for purposes of 860.1500 data requirements.

2 The number of days grass was allowed to dry in the field prior to collection is reported in parenthesis.

3 For all analytes and all matrices: LOQ = 0.0 42 ppm ; the calculated LOD for DME and DME

- OH was 0.007 and 0.005 ppm in forage and 0.013 and 0.004 ppm in hay, respectively. Each value represents the average of duplicate analyses of a single sample.

4 Reported as Sethoxydim equivalents by the petitioner based on the quantified residues of DME x 1.11 and DME

- OH x 1.05.

TABLE C.4. Summary of Residue Data from Grass Crop Field Trials with Sethoxydim

. Commodity Analyte Total App.

Rate ( lb ai/A ) PHI

(days) Residue Levels (ppm) 1

n Sample
Min. Sample

Max. L AFT 2 HAFT 2 Median Mean Std.

Dev.

Grass forage DME 3 0.936

- 0.973 13

- 14 4 1.0 2.8 1.4 2.7 1.5 1.8 0.63

DME

- OH 3 4 0.21 0.42 0.22 0.34 0.29 0.29 0.07

Combined 4 1.24 3.16 1.65 3.04 1.74 2.04 0.67

Grass hay DME 3 21

- 28 4 0.48 1.3 0.65 1.1 0.84 0.86 0.19

DME

- OH 3 4 0.14 0.40 0.15 0.35 0.30 0.27 0.09

Combined 4 0.75 1.45 0.98 1.26 1.16 1.14 0.14

1 Except for sample min/max, values reflect per trial averages; n = no. of field trials. For calculation of median, mean, and standard deviation, the LOQ (0. 042 ppm for all analytes) was used for any results reported as < LOQ in Table C.3.

2 LAFT = lowest average field trial; HAFT = highest a verage f ield t rial.

3 Residues of DME and DME

- OH are reported in sethoxydim parent equivalents as calculated by the petitioner

.Sethoxydim /PC Code 121001/ Interregional Research Project No. 4 DACO 7.4.1/7.4.2/OCSPP 860.1500/OECD IIA 6.3.1, 6.3.2, 6.3.3 and IIIA 8.3.1, 8.3.2, 8.3.3 Crop Field Trial

– Fine Fescue Grass (grown for seed)

DP# 4 22744 / MRID No. 49257702 Page 12 of 12 

### D. CONCLUSION

The submitted fine fescue grass field trial data are acceptable. Following two foliar broadcast applications of the 1.5 lb ai/gal EC formulation of sethoxydim at a total rate of 0.936

- 0.973 lb ai/A, residues (and per trial averages) of sethoxydim equivalents, (determined as DME, DME

OH, and c ombined residues; respectively, were: 1.0

- 2.8 (1. 4

- 2.7), 0.21

- 0.42 (0.22

- 0.34), and
1.24

- 3.16 (1.65

- 3.04) ppm, in/on fine fescue grass forage harvested at a 13

- to 14

- day PHI ; and
0.48

- 1.3 (0.65

- 1.1), 0.14

- 0.40 (0.15

- 0.35), and 0.75

- 1.45 (0.98

- 1.26), in / on fine fescue grass hay
harvested at a 21

- to 28

- day PHI.

A n a cceptable method w as used for residues quantitation, and the study is supported by adequate storage stability data.

E. REFERENCES

Draft Memo

, dated 9/30/00, Additional Guidance on the Cr op

– ‘ Grasses Grown for S eed ’

, Grasses Grown for Seed Policy Team ( P. Errico, J

. Fleuchaus, B

. Hazel, H

. Jamerson, J

. Kempter, R

. Loranger, J . S mith, and J . T ompkins)

F. DOCUMENT TRACKING

RDI: P. Savoia 11/19/2014 Petition Number(s): 4E8239 DP Barcode(s): D422744
PC Code: 121001

Template Version June 2005.