Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 1 of 30 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

MEMORANDUM

Date : 06/2 8 / 2012

SUBJECT: Halosulfuron

- methyl

. Application for Section 3 Registration of Yukon Herbicide

(EPA Reg. No. 81880

- 6 ), Sandea Herbicide ( EPA Reg. No. 81880

- 18 )

, and

GWN

- 3061 Herbicide ( EPA Reg. No. 81880

- 2) to Add New Uses on Proso Millet

and Pasture and Rangeland Grasses. Summary of Analytical Chemistry and

Residue Data.

PC Code: 128721 DP Barcode: D393948

Decision No.: 453868 Registration No s

. : 81880

- 2, 81880

- 6, 81880

- 18

Petition No.: 1F7916 Regulatory Action: Section 3 Registration Risk Assessment Type: NA Case No.: NA

T XR No.: NA CAS No.: 100784

- 20

- 1

MRID No s .: 48 583601 and 48583602 40 CFR: § 180.479

FROM: Meheret Negussie , Chemist

Risk Assessment Branch III Health Effects Division (HED ) ( 7509P)

THROUGH: Leung Cheng, Senior Chemist

Risk Assessment Branch II I Health Effects Division (HED ) ( 7509P)

TO: Kable Davis/ Maggie Rudick RM 25

Herbicide Branch

R egistration Division (7505P)

Note: This document was originally prepared under contract by Versar, Inc. (6850 Versar Center, Springfield, VA 22151; submitted 3/30/12). The document has been reviewed by the Health Effects Division (HED) and revised to reflect current Office of Pesticide Programs (OPP) policies.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 2 of 30 Executive Summary

Halo sulfuron

- methyl is a selective herbicide belonging to the su lfonylurea group of herbicide s

. It s mode of action includes the inhibit ion of a specific plant enzyme , acetolacetate synthase

. Halosulfuron

- methyl is registered for the pre

- and postemergence co ntrol of annual broadleaf weeds and nutsedges in selected crops, as well as residential turf grass and ornamentals

. Halosulfuron

- methyl is sold in the U.S. as a dry flowable/ water

- dispersible granule formulation.

The petitioner, Canyon Group LLC (agent G owan Company) has submitted a request for amended registration of a 12.5% water dispersible granule ( WG ) formulation of halosulfuron

methyl (Yukon Herbicide; EPA Reg. No. 81880

- 6; MAI containing 55% dicamba) and two 75% WG formulations (Sandea Herbicide, E PA Reg. No. 81880

- 18, and GWN

- 3061, EPA Reg. No.

81880

- 2) for use on proso millet and pasture and rangeland grasses. The proposed uses reflect foliar broadcast application to proso millet at 0.023

- 0.0313 lb ai/A o r to pasture and rangeland grasses at 0.03 13

- 0.0625 lb ai/A. The proposed preharvest intervals ( PHIs ) are 0 days and 7 or 14 days for forage and 37 days for hay (both crops); no PHI has been proposed for millet grain

and straw.

In conjunction with the proposed uses, Canyon Group has requested t he establishment of

tolerances for the herbicide halosulfuron

- methyl in/on the following commodities:

Millet, proso, forage

................................ ........................... 7.0 ppm Millet, proso, hay

................................ ............................... 0.0 2 ppm Millet, proso, grain

................................ ............................. 0.0 1 ppm Millet, proso, straw

................................ ............................ 0.0 1 ppm Grass forage, fodder, and hay, Crop group 17 forage.... 17.0 ppm Grass forage, fodder, and hay, Crop group 17 hay

. ..... 0.90 ppm

There are a number of discrepancies in the directions for use for this action

. For millet forage, there is a discrepancy between the PHIs/ pregrazing intervals ( PGIs ) for forage specified on the submitted draft labels (0 days for non

- lactating animals and 7 days for lactating animals) and that which

appear s in the petition under Reasonable Grounds in Support of Petition (7 days for all animals)

. The available residue data will support PHIs/PGIs of 0 and/or 7 days

. In addition, a PHI must be proposed for millet grain and straw. For grass, the use pattern for forage must be amended to specify

a 0

- day PGI for all animals. Finally, the labels specify a 30

- day preslaugh ter interval (PSI) for both crops which must be removed because HED has previously concluded that a PSI of this length is not practical for pesticides.

Permanent tolerances are established under §180.479(a)(1) for residues of halosulfuron

- methyl including its metabolites and degradates in livestock commodities to be determined by measuring only those halosulfuron

- methyl residues containing the 3

- chlorosulfonamide (3

- CSA) moiety

, expressed as halosulfuron

- methyl equivalent s
, for the meat byproducts of cattl e, goat, hog, horse, and sheep at 0.1 ppm. Tolerances are established for a variety of field, fruit, and vegetable crop

commodities under §180.479(a)(2) for residues to be determined by measuring only

halosulfuron

- methyl, at levels ranging from 0.05 to 2. 0 ppm.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 3 of 30 The nature of the residue in plants is adequately understood based on acceptable metabolism

studies with corn, sugarcane, and soybean treated both pre

- and postemergence

. The terminal

residue of co ncern in plants is halosulfuron

- methyl

.

The nat ure of the residue in ruminants and poultry is adequately understood based on acceptable
goat and hen metabolism stud ies

. T he residue of concern in r uminants and poultry is

halosulfuron

- methyl. H owever, because the approved enforcement method for livesto ck commodities quantifies the parent compound and metabolites containing the 3

- CSA by converting residues to 3

- CSA, tolerances for residues in livestock commodities are expressed in

terms of halosulfuron

- methyl and its metabolites determined as 3

- CSA, expr essed as

halosulfuron

- methyl equivalents.

Adequate analytical methods are available for the enforcement of tolerances for residues of

halosulfuron

- methyl in plants (Method RES

- 109

- 97

- 4), and for residues of halosulfuron

- methyl

and its 3

- CSA metabolites in livestock commodities (Method RES

- 046

- 93). Samples from the submitted field trial studies were analyzed for residues of halosulfuron

- methyl using a modified

version of the plant enforcement method (gas chromatography with nitrogen phosphorus or mass

se lective detection; GC/NPD or GC/MSD) with a petitioner

- validated limit of quantitation (LOQ; determined as the lowest level of method validation; LLMV) of 0.01 ppm. The method

was adequate for data collection based on acceptable concurrent method recoveri es, and the fortification levels used in concurrent method recovery were adequate to bracket expected

residue levels.

Residues of halosulfuron

- methyl and 3

- CSA are not adequately recovered by FDA Multiresidue Method protocols

.

A dequate storage stability data are available to support the storage conditions and durations of samples collected from the submitted crop field trials on proso millet and grass. As residues of

halosulfuron

- methyl were found to be stable in tested crop matrices, storage stability c orrections

need not be applied

.

There are animal feedstuffs associated with the proposed uses on proso millet and grasses. An acceptable feeding study was previously submitted reflecting dosing of lactating dairy cows with

halosulfuron

- methyl at 0.5, 1 .5, and 5 ppm in the daily diet on a dry weight basis

. In the study,

n o quantifiable residues (<0.01 ppm) were found in milk, muscle, or fat at any feeding level; quantifiable residues were found in liver and kidney at all feeding levels. With the recalc ulated dietary burden for dairy cattle ( from 0.825 ppm to 20 ppm ) , the dose rates in the feeding study correspond to ~0.0 25 x, ~0.0 75 x, and ~0.25x the current maximum reasonable dietary burden ( MRBD ). Based on extrapolation from the highest concentration l evel (5 ppm) of the feeding study with residues at the LOQ (0.01 ppm) in milk, muscle, and fat, HED has concluded that tolerances at 0.05 ppm can be established for residues of halosulfuron

- methyl in the milk, muscle and fat of cattle, goats, horses, and s heep based on the reasons stated in the ChemSAC minutes (ChemSAC 06/20/2012). The petitioner must propose a tolerance of 0.05 ppm for these

livestock commodities. For future new uses that increase the dietary burden above 20 ppm, a new feeding study will be needed reflecting dosing at 1x, 3x, and 10x the maximum reasonable dietary burden (MRDB).Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 4 of 30 The available data for liver and kidney are sufficient to assess the existing tolerances for meat byproducts. The data indicate that the established toleranc es of 0.1 ppm for the meat byproducts of cattle, goat, horse, and sheep are too low and should be increased to 1. 0 ppm. No change is needed for the established tolerance of 0.1 ppm for hog meat byproducts, and tolerances for

halosulfuron

- methyl residues i n poultry commodities are not required due to low use rates, low

residues of halosulfuron

- methyl in poultry feed items, and the low transfer rate of residues to poultry tissues.

Acceptable crop field trial data have been submitted on proso millet

. The tr ials reflect a single foliar broadcast application of a WG formulation at a target application rate of 0.0313 lb ai/A ; a

non

- ionic surfactant ( NIS ) was used in all trials. Residues in/on proso millet hay, grain, and straw were below the LOQ . T he availabl e data will support tolerances at the LOQ of 0.01 ppm

for these commodities , provided the petitioner proposes a PHI of 50 days for grain and straw

. Quantifiable residues were observed in/on forage harvested at 0

- and 7

- day PHIs. The data will
support a t olerance of 10 ppm for millet for age with a 0

- day PHI

.

Acceptable crop field trial data have been submitted on pasture and rangeland grass es . The trials reflect a single foliar broadcast application of a WG formulation of halosulfuron

- methyl at a
target application rate of 0.0625 lb ai/A ; an NIS was used in all trials. T he data will support

tolerances of 20 pp m for forage ( based on a 0

- day PG I ) and 0.5 0 ppm for hay.

D ifference s in proposed and recommended tolerances may be attributed to the petitioner having used the NAFTA tolerance calculation procedures for determining the tolerance and HED’s having used the OECD tolerance calculation procedures ; for grass hay, the petitioner used values below the LOQ in the tolerance calculation.

Adequate confined and limited field rotational crop data are available. HED previously

concluded that the residue of concern in r otational crops is halosulfuron

- methyl

. Based on the absence of the parent compound in the confined studies and in the limited field rotational crop studies, with the exception of one forage sample, HED previously concluded that rotational crop tolerances and restrictions are not required for halosulfuron

- methyl.

There are no Codex, Canadian, or Mexican maximum residue limits ( MRLs ) establish ed for

residues of halosulfuron

- methyl in crop or livestock commodities

.

Regulatory Recommendations and Residue Chemistry Deficiencies

HED has examined the residue chemistry database for halosulfuron

- methyl and evaluated the adequacy o f study submissions associated with the current action. Pending submission of a revised Section B, a revised Section F , and an analytical standard for the Rearrangement ester (RRE) of halosulfuron

- methyl , there are no residue chemistry data gaps that wou ld preclude granting un conditional registration for the requested use of halosulfuron

- methyl on proso millet

and pasture and rangeland grasses. The proposed use s and the submitted data support the following tolerances for residues of halosulfuron

- methyl i n/on the following commodities:

Millet, proso, forage

................................ ................................ ................ 10 ppm Millet, proso, hay

................................ ................................ .................. 0.01 ppmHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 5 of 30 Millet, proso, grain

................................ ................................ .............. 0.01 ppm Millet, proso, straw

................................ ................................ .............. 0.01 ppm Grass, forage, fodder, and hay, group 17, f orage

................................ .... 20 ppm Grass, forage, fodder, and hay, group 17, hay

................................ ........ 0 .5 ppm

The proposed uses nec e ssitates the establishment of tolerances as follow :

Cattle, fat

................................ ................................ .............................. 0.05 ppm Cattle, meat

................................ ................................ ........................... 0.05 ppm Goat, fat

................................ ................................ ................................ 0.05 ppm Goat, meat

................................ ................................ ............................ 0.05 ppm Horse, fat

................................ ................................ .............................. 0.05 ppm Horse, meat

................................ ................................ ........................... 0.05 ppm Milk

................................ ................................ ................................ ...... 0.05 ppm Sheep, fat

................................ ................................ .............................. 0.05 ppm Sheep, meat

................................ ................................ .......................... 0.05 ppm

The proposed requested use on proso millet and grasses necessitates the revision of existing

tolerances for halosulfuron

- methyl residues c ontaining 3

- CSA in/on livestock commodities as

follow:

Cattle, meat byproducts

................................ ................................ .......... 1. 0 ppm Goat, meat byproducts

................................ ................................ ............ 1. 0 ppm Horse , meat byproducts

................................ ................................ .......... 1.0 ppm Sheep, meat byproducts

................................ ................................ .......... 1 .0 ppm

A human health risk assessment is forthcoming.

860.1200 Directions for Use

The following label revisions are needed:

For all labels, the preharvest interval (PHI) and pregrazing inte rval (PGI) for millet forage

should be revised to 0

- day PHI.

All labels should be revised to:

o Specify a 37

- day PHI for proso millet hay and a 50

- day PHI for proso millet grain

and straw.

o Specify a 0

- day PGI for grass forage for all animals (beef, lactating and non

lactating).

o Because crop oil concentrates (COC) were not used in any of the submitted crop field trials on proso millet or grass, the labels for the 12.5% and 75% WG formulations should be revised to state that only non

- ionic surfactants (NIS) adj uvants may be added to the spray mixtures for these crops.

o Remove the recommended 30

- day pre

- slaughter interval (PSI).Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 6 of 30 860.1550 Proposed Tolerances

The petitioner should submit a revised Section F reflecting the recommended tolerances and commodity d efinitions presented in Table 10

.

860.1650 Submittal of Analytical Reference Standards

An an alytical reference standard for the RRE of halosulfuron

- methyl must be submitted to the EPA National Pesticide Standards Repository.

Backgr ound

The chemical structure s and nomenclature s of halosulfuron

- methyl and the 3

- CSA moiety are presented in Table 1. The physicochemical properties of the technical grade of halosulfuron

methyl are presented in Table 2.

Table 1. Halosulfuron

- methyl Nom enclature

. Chemical structure

Common name halosulfuron

- methyl

Company experimental name MON 12000, NC

- 319

IUPAC name methyl 3

- chloro

- 5

- (4,6

- dimethoxypyrimidin

- 2

- ylcarb amoyl sulf amoyl)

- 1

- methylpyrazole

- 4

- carboxylate

CAS name methyl 3

- chloro

- 5

- [[[[(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]amino]sulfonyl]

- 1

- methyl

- 1 H

- pyrazole

- 4

- carboxylate

CAS registry number 100784

- 20

- 1

End

- use product (EP) 12.5% WG (Yukon Herbicide; EPA Reg. No. 81880

- 6; MAI containing 55% dicamba) 75% WG (Sandea Herbicide; EPA Reg . No. 81880

- 18) 75% WG (GWN

- 3061; EPA Reg. No. 81880

- 2)

Chemical structure of

3

- chlorosulfonamide moiety (3

- CSA)

3

- chloro

- 1

- methyl

- 5

- sulfamoyl

- 1 H

- pyrazole

- 4

- carboxylic acidHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 7 of 30 Table 2. Physicochemical Properties of Halosulfuron

- methyl

. Parameter Value R eference

Melting range 175.5

- 177.2oC MRID 42139403; DP#s 173627 & 180565, 7/30/92,

G.J. Herndon pH 4.11 at 25oC (1% w/v slurry)

Density 1.618 g/mL at 25oC

Water solubility at 20oC pH 5 0.0015 g/100 mL pH 7 0.165 g/100 mL pH 9 0.747 g/100 mL

Solvent solubility at 20oC methanol 0.1616 g/100 mL

n

- hexane 0.001278 g/100 mL

Vapor pressure <1 x 10 - 7 mm Hg at 25oC

Dissociation constant, K

a 3.61 x 10 - 4 at 22.4oC

Octanol/water partition coefficient, Log(K OW ) at 23oC 1.67 at pH 5

- 0.0186 at pH 7

- 0.542 a t pH 9

UV/visible absorption spectrum Not available

860.1200 Directions for Use

In support of the proposed uses on proso millet and pasture and rangeland grasses, Canyon Group has submitted draft labels for the following end

- use product s : a 1 2.5% WG formulation (Yukon Herbicide; EPA Reg. No. 81880

- 6; MAI containing 55% dicamba) ; and two 75% WG formulations (Sandea Herbicide, EPA Reg. No. 81880

- 18

, and GWN

- 3061, EPA Reg. No.

81880

- 2). In addition, the proposed use patterns are summarized in the petit ion materials under

“ Residue Chemistry including Reasonable Grounds in Support of Petition

. ”

The proposed use pattern information is presented in Table 3. HED note s that there are discrepancies between the PHIs/PGIs specified on different labels and summ arized in the petition

materials.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 8 of 30 Table 3. Summary of Directions for Use of Halosulfuron

- methyl.

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate

oz/A (lb ai/A) Max. No.

Applic. per

Season Max.

Seasonal Applic.

Rate

oz/A ( lb ai/A) PHI/PGI 1

(Days) Use Directions and Limitations 2

Proso Millet

Post weed emergence and actively growing weeds; Foliar, Broadcast,

G round or aerial; 12.5% WG

[81880

- 6] 3

- 4 oz/A

(0.0234

- 0.0313 ) Not

specified ( NS ) 4 oz/A

( 0. 0 313 ) Forage

Beef & no n

lactating:

0 Lactating dairy:

7

Hay

37 Apply at the 3

- to 5

- leaf stage. A PSI of 30 days is specified

for beef and non

- lactating

animals.

Master Label : Apply in minimum spray

volumes of 5

- 15 gal/A ( GPA ) by air or 1 0 GPA by ground. Do not apply throu gh any type of irrigation system. Avoid disturbing (cultivation)

treated areas for at least 7

- days following application.

A non

- ionic surfactant is required at 0.25 to 0.5% v/v or a crop oil concentrate may be

used instead at 1% v/v.

Post weed

emergence and actively growing

weeds ; Foliar, Broadcast, ground or band application,

aerial 75% WG

[ 81880

- 18 ] 0.5

- 0.67

(0.0234

- 0.0313 ) NS 0.67

( 0.0313 ) 0 Apply at the 2

- leaf through layby stage (before grain head emergence)

.

Master Label: Ground (min. 15 gal/A) or aerial (3

- 15 gal/A)

. Do not apply using air assisted (air blast) field crop sprayers. Do not apply through any type of irrigation system. Do not apply more than 2 oz/A per 12 month period (includes applications to the crop and to row middles/furrows).

A non

- ionic surfactant is

recommended at 0.25 to 0.5% v/v or a crop oil concentrate at

1% v/v.

Use of a COC or silicone

- based adjuvants can result in crop injury and reduced yields and

are not recommended for
postemergence.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 9 of 30 Table 3. Summary of Directions for Use of Halosulfuron

- methyl.

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate

oz/A (lb ai/A) Max. No.

Applic. per

Season Max.

Seasonal Applic.

Rate

oz/A ( lb ai/A) PHI/PGI 1

(Days) Use Directions and Limitations 2

Post weed emergence and

active ly growing

weeds ; Foliar, Broadcast, ground or band application,

aerial 75% WG

[ 81880

- 2] 0.5

- 0.67

(0.0234

- 0.0313 ) NS 0.67

( 0.0313 ) 0 Apply at the 2

- leaf through layby stage (before grain head emergence)

.

Master Label : Apply in minimum spray volumes o f 3

- 15 GPA by

air or 10 GPA by ground. Do not apply through any type of irrigation system. Avoid disturbing (cultivation)

treated areas for at least 7

- days following application.

A non

- ionic surfactant is required at 0.25 to 0.5% v/v or a crop oil conce ntrate may be

used instead at 1% v/v.

Pasture and Rangeland Grasses

Post weed

emergence; Foliar, Broadcast,

G round or aerial; 12.5% WG

[ 81880

- 6] 4

- 8 oz/A

(0.0313

- 0.0625 ) NS 8 oz/A

( 0.0625 ) Forage

Beef & non

lactating:

0 Lactating dairy:

14

Hay

37 A P SI of 30 days is specified

for beef and non

- lactating

animals.

Same as the master label under proso millet.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 10 of 30 Table 3. Summary of Directions for Use of Halosulfuron

- methyl.

Applic. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Applic.

Rate

oz/A (lb ai/A) Max. No.

Applic. per

Season Max.

Seasonal Applic.

Rate

oz/A ( lb ai/A) PHI/PGI 1

(Days) Use Directions and Limitations 2

Postemergence 3

Foliar broadcast

Ground

or aerial 75% WG

[81880

- 18 ] 0.67

- 1.33

(0.0313

- 0.0625 NS 1.33

( 0.0625 ) Forage

Beef & non

lactating:

0

Lac tating dairy:

14

Hay

37 Apply to established pasture and rangeland. A PSI of 30 days is specified for beef and

non

- lactating animals. Ground (min. 1 0 gal/A)

Same as the master label under proso millet, except for g round application use min. 1 0 gal/A

.

Postemergence 3

Foliar broadcast

Ground

or aerial 75% WG

[81880

- 2] 0.67

- 1.33

(0.0313

- 0.0625 NS 1.33

( 0.0625 ) Forage

Beef & non

lactating:

0 Lactating dairy:

14

Hay

37 Apply to established pasture and rangeland. A PSI of 30 days is specified for beef a nd

non

- lactating animals.

Same as the master label under proso millet.

1 The proposed use pattern as described in the petition materials under “Residue Chemistry including Reasonable Grounds in Support of Petition” indicates that the proposed pregrazi ng intervals are: 7 days for all animals for proso millet; and 7 days for lactating animals and 0 days for all other animals for pasture and rangeland grasses.

2 PSI = Preslaughter interval.

3 The labels for the 75% WG formulations also include direct ions for spot treatment applications to grasses which are not presented herein.

Adjuvants: The labels for the 12.5% (81880

- 6) WG formulation and 75% WG formulation (81880

- 2) state that a n NIS is required at a rate of 0.25

- 0.5% v/v , and that a crop oil co ncentrate ( COC ) may also be used instead of a n NIS, at 1% v/v. The label for the other 75% WG

formulation (81880

- 18) states that use of a n NIS (0.25

- 0.5% v/v) is recommended , and that a COC or silicone

- based adjuvant is not recommended for postemergence a pplications over the

crop

.

Rotational crop restriction s : Plantback restrictions are also specified for a number of crops, ranging from 0 months for insecticide

- /imidazolidone

- resistant field corn

, rice, and sugarcane, to 36 months for sugar beet in ND, MN , and the Red River Valley

, and strawberry

. HED previously determined that rotational crop tolerances/restrictions are not needed for halosulfuron

methyl . The restrictions appear to have been established for protection of the rotated crops from

residual herbicidal activity.

Conclusions

. The submitted use directions are adequate to allow evaluation of the submitted residue data relative to the proposed use s

. The submitted field trial data for proso millet andHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 11 of 30 grass reflect the maximum proposed use rate and the minimum PHI and support the use of an NIS spray adjuvant

.

For millet forage, t here is a discrepanc y between the PHIs/PGIs for forage specified on the

submitted draft labels (0 days for non

- lactating animals and 7 days for lactating animals) and that which appear s in the petition under Reasonable Grounds in Support of Petition (7 days for all

animals )

. The available residue data will support PHIs/PGIs of 0 and/or 7 days . HED recommends a tolerance of 10 ppm based on a 0

- day residue data

. T he pe titioner should revise the PHI/PGI for millet forage to 0

- day PHI for all labels

.

For millet hay, grain, and straw, the petitioner has proposed a 37

- day P HI for hay on the label for the 12.5% WG formulation, but has not proposed a PHI for grain and str aw ; the labels for the 75% WG formulations propose a 0

- day PHI for millet in general. T he available residue data will
support the proposed PHI of 37 days for hay and a 50

- day PHI for millet grain and straw

. The

labels for the 75% WG formulations should b e revised to specify a PHI of 37 days for hay , and the labels for the 12.5% and 75% WG formulations should be revised to specify a PHI of 50 days for grain and straw

.

For grass

, although the available residue data will support a PHI/PGI for forage of 0 or 7 days,

p er OCSPP 860.1000 Table 1, a 0

- day PGI is required for grass forage except for grasses grown for seed only . The data will support the proposed PHI of 37 days for hay. The labels for the

12.5% and 75% WG formulations should be revised to speci fy a 0

- day PHI/ PGI for grass forage

for all animals.

Because c rop oil concentrates were not used in any of the submitted crop field trials on proso

millet or grass , t he labels for the 12.5% and 75% WG formulations should be revised to state that only NI S adjuvants may be added to the spray mixtures for these crops.

Finally, HED had previously concluded that a 30

- day PSI is not practical for pesticides (refer to the minutes of the 12/6/06 ChemSAC meeting). The recommended 30

- day PSI must be removed

fr om the labels for the for the 12.5% and 75% WG formulations

.

860.1300 Nature of the Residue

- Plants

DP# 251007, M. Doherty, 12/10/ 19 98 Metabolism Committee decision, G . Herndon

, 5/21/ 19 96

DP# 198361

, G. Otakie , 7/21/ 19 94

DP# s173627 & 180565, G. Herndo n , 7/30/ 19 92Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 12 of 30 The nature of the residue in plants is adequately understood based on acceptable metabolism

studies reflecting pre

- and postemergence modes of applications on corn, sugarcane, and soybean. The metabolism of halosulfuron

- methyl was similar in the three tested crops but dependent on the mode of application. When halosulfuron

- methyl was applied preemergence, initial breakdown of the herbicide in the soil and preferential uptake of the pyrazole moieties resulted in the primary residue being 3

- CSA , which has been determined to be less toxic than the parent. With a postemergence application, the major residue was the parent compound with minimal translocation of the herbicide in the plant, except in grain where the major residue was

3

- CSA.

Based on the very low toxicity of the metabolite 3

- CSA, relatively low toxicity of the parent compound, and low residue levels of both parent compound and the 3

- CSA metabolite, HED has previously determined that the residue of concern in pl ants is the parent compound, halosulfuron

methyl.

860.1300 Nature of the Residue

- Livestock

DP# 223801, 11/17/ 19 98, M. Doherty Metabolism Committee decision, G . Herndon

, 5/21/ 19 96

DP# 204062, G. Herndon , 6/22/1994

DP# 184435, G. Herndon , 1/15/1993

DP# 1 81023, G. Herndon , 11/12/1992

DP# s 173627 & 180565, G. Herndon , 7/30/1992

Acceptable goat metabolism and hen metabolism stud ies w ere previously submitted and

reviewed in conjunction with petitions for uses on corn and sorghum. In goat milk and tissues, the major extractable residue was the parent; acid hydrolysis released bound or conjugated

residues of aminopyrimidine and 3

- CSA. HED has previously determined that the residue of

concern in ruminants is halosulfuron

- methyl; however, because the approved enforcement method for livestock commodities quantifies the parent compound and metabolites containing

the 3

- chlorosulfonamide moiety (3

- CSA) moiety by converting residues to 3

- CSA, tolerances for residues in livestock commodities are expressed in terms of halosulfuron

- methyl and its

metabolites determined as 3

- CSA, expressed as halosulfuron

- methyl equivalents.

HED previously concluded (PP#2G4073) that tolerances for halosulfuron

- methyl residues in poultry commodities were not required due to low use rat es, low residues of halosulfuro n

- methyl in poultry feed items

, and the low transfer rate of residues to poultry tissues.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 13 of 30 860.1340 Residue Analytical Methods

DP# 250584, G. Herndon , 10/28/1998

DP# 214890, G. Herndon , 5/3/1995

DP# 202131, G. Herndon , 1 0/4/1994

Plants

Enforcement method: An adequate analytical method is available for enforcement of tolerances

for halosulfuron

- methyl residues in plants. The GC /TSD method quantifies halosulfuron

- methyl

as its rearrangement ester (1

- H

- pyrazole

- 4

- carboxy lic acid, 3

- chloro

- 5

- [(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]

- 1

- methyl, methyl ester). Monsanto Analytical Method RES

- 109

- 97

- 4 (MRID 44495801) has been validated as an enforcement method by the Analytical Chemistry Branch (ACB)/BEAD. The LOQ on rice straw, s ugarcane, milo grain, field corn grain, cotton gin byproducts, and almond nutmeats was 0.05 ppm ( DP# 250584, G. Herndon, 10/28/ 19 98).

Rearrangement ester (RRE) of halosulfuron

- methyl

Data collection method

s : Samples collected from the field trial s tudies associated with this

action were analyzed for residues of halosulfuron

- methyl using the available tolerance enforcement method, Method RES

- 109

- 97

- 4, with modifications. Briefly, samples were extracted with acetonitrile (ACN)/water, filtered, and pa rtitioned with dichloromethane (DCM). The DCM extract was evaporated to dryness and redissolved in 15% methanol/DCM for clean

- up through a Florisil solid phase extraction (SPE) cartridge. The eluate was mixed with 0.5 M potassium carbonate to convert hal osulfuron

- methyl residues to its rearrangement ester (RRE).

The reaction mixture was then extracted with DCM, and the DCM extract was evaporated to dryness; residues were reconstituted in ethyl acetate for further clean

- up through a silica SPE

column. Th e eluate was evaporated to dryness and redissolved in 50% ethyl acetate/isooctane for analysis by GC/NPD or GC/MSD

. The LOQ (determined as the LLMV) was 0.01 ppm in all proso millet and grass matrices.

Conclusions . The residue analytical methods data ar e adequate to satisfy data requirements for the subject action. An a cceptable residue analytical method is available for tolerance enforcement purposes for residues in/on crop commodities . R esidues of halosulfuron

- methyl

in/on the crop commodities from t he magnitude of the residue studies were determined using an acceptable data collection method.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 14 of 30 Livestock

Enforcement method: An adequate analytical method is available for enforcement of tolerances for secondary residues of halosulfuron

- methyl in lives tock commodities. Monsanto Analytical

Method RES

- 046

- 93 quantifies halosulfuron

- methyl and metabolites containing the 3

- CSA moiety, expressed as parent equivalents. Residues of halosulfuron

- methyl and 3

- chlorosulfonamide ester are hydrolyzed to 3

- CSA, wh ich is extracted with ACN/DCM and then methylated with trimethylsilyl

- diazomethane. The methyl ester is analyzed by GC / ECD after cleanup with an alumina/carbon column. The petitioner

- validated LOQ was 0.01 ppm

. The

method has been validated as an enforc ement method by the ACB/BEAD at an LOQ of 0.01 ppm in milk and liver (D. Swineford, 4/28/ 19 95)

.

860.1360 Multiresidue Methods

DP# 189198, G.Herndon , 3/8/ 19 94

Adequate multiresidue method data for halosulfuron

- methyl and 3

- CSA were submitted previously i n conjunction with PP# 3F4193

. Residues of halosulfuron

- methyl and 3

- CSA are not recoverable by the FDA Multiresidue Protocols A through E. The results have been forwarded to

FDA.

860.1380 Storage Stability

DP# 189189, 3/8/94, G. Herndon DP# 243050, 1/5 /99, M. Doherty

Adequate stor age stability data were previously submitted which indicate that halosulfuron

methyl residues are stable during freezer storage for up to 800 days in /on corn grain, forage, fodder, and silage ( DP# 189198, 3/8/94, G. Herndon) a nd 996 days in /on soybean (DP# 243050

, 1/5/99, M. Doherty).

The storage durations and conditions of crop samples from the sub mitted crop field trials are presented in Table 4. N o concurrent storage stability information was provided.

Table 4. Summa ry of Storage Conditions and Durations of Samples from Crop Field Trials.

Matrix Storage

Temperature (°C) Actual Storage Duration

(days) Interval of Demonstrated

Storage Stability for Halosulfuron

methyl (days)

M illet forage

- 20 ± 5 171

- 237 days (5. 6

- 7.8 months) Residues of halosulfuron

- methyl are stable during freezer storage for up to 800 days in corn grain, forage, fodder, and silage and 996 days in soybean. M illet hay 120

- 186 days ( 3.9

- 6.1 months)

M illet grain 142

- 177 days (4.7

- 5.8 months)

Millet s traw 99

- 157 days (3.3

- 5.2 months)

Grass forage

- 20 ± 5 95

- 275 days (3.1

- 9.0 months)

Grass hay 55

- 236 days ( 1.8

- 7.8 months)

Conclusions

. Adequate storage stability data are available to support the storage conditions and durations of samp les collected from the magnitude of the residue studies on proso millet andHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 15 of 30 grass

. As residues of halosulfuron

- methyl were found to be stable in some related crop matrices, storage stability corrections need not be applied

.

860.1400 Water, Fish, and Irri gated Crops

There are no proposed uses that are relevant to this guideline topic.

860.1460 Food Handling

There are no proposed uses that are relevant to this guideline topic.

860.1480 Meat, Milk, Poultry, and Eggs

DP# 367058, D. Rate, 3/30/2010

DP# s 1 89198 & 198051 , G. Herndon, 3/8/ 19 94

DP#s 173627 & 180565, G. Herndon, 7/30/1992

The livestock feedstuffs associated with the proposed uses on proso millet and grasses are : millet forage, hay

, and straw ; and grass forage, hay, and silage. The feedstuf fs derived from registered uses include those commodities derived from alfalfa, almond, apple, corn, c otton, dry and snap beans, potato, rice, sorghum, soybean , and sugarcane.

Maximum reasonable dietary burdens (MRDBs) for ruminants were most recently c alculated for

halosulfuron

- methyl under PP#9E7577 (DP# 367058) reflecting proposed uses on apple and potato. The calculated dietary burdens were 0.468 ppm for beef cattle and 0.825 ppm for dairy

cattle.

The addition of uses on millet and grasses will hav e a significant impact on the dietary burden to dairy cattle

. The addition of grass and/or millet feedstuffs to the dietary burden calculations for beef cattle, even at the maximum potential contribution for each

, will not increase the dietary

burden. Si milarly, the addition of millet grain to the dietary burden calculations for poultry and swine will not increase the dietary burden ; no significant intake was previously found for poultry

or swine

.

The MRDB calculations reflecting the addition of millet a nd grass feedstuffs are presented in

Table 5

. The dietary burden for ruminants remains unchanged at 0.468 ppm; the current dietary burden for dairy cattle is 19. 9 ppm.

Table 5

. Calculation of Dietary Burdens of Halosulfuron

- methyl Residues to Livestoc k.

Feedstuff Type 1 % Dry

Matter 2 % Diet 2 Recommended

Tolerance / HAFT 3
(ppm) Dietary Contribution

(ppm) 4

Beef Cattle

Alfalfa, hay R 89 15 2.0 (Tolerance) 0.337

Potato, processed waste CC 15 30 0.05 (Tolerance) 0.100

Corn, field, grain CC 88 50 0.05 (Tol erance) 0.028

Soybean, meal PC 92 5 0.05 (Tolerance) 0.003Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 16 of 30 Table 5

. Calculation of Dietary Burdens of Halosulfuron

- methyl Residues to Livestoc k.

Feedstuff Type 1 % Dry

Matter 2 % Diet 2 Recommended

Tolerance / HAFT 3
(ppm) Dietary Contribution

(ppm) 4

Beef Cattle

TOTAL BURDEN

-- -- 100

-- 0.468

Dairy Cattle

Grass, forage/silage R 25 45 11.0 (HAFT) 19.8

Potato, processed waste CC 15 10 0.05 (Tolerance) 0.033

Corn, field, grain CC 88 35 0.05 (Tolerance) 0.020

Cotton, meal PC 89 10 0.05 (Tolerance) 0.006

TOTAL BURDEN

-- -- 100

-- 19. 9

1 R: Roughage; CC: Carbohydrate concen trate; PC: Protein concentrate

2 OPPTS 860.1000 Table 1 Feedstuffs ( June 2008).

3 The HAFT from the crop field trials was used fo r grass forage; tolerances were used for all other commodities.

4 Contribution = ([toleranc e /% DM] X % diet) for dairy cattle

.

Dairy Cattle

An adequate dairy cattle feeding study was submitted under PP#3F4193 (DP#s 189198 and 198051). Halosulfuron

- meth yl was administered in gelatin capsules to lactating dairy cattle (four animals/dose group) once daily for 28 consecutive days at three dose levels roughly equivalent to 0.5, 1.5, and 5 ppm in the daily diet on a dry weight basis ( cor respond ing to ~0.0 25 x, ~0.0 75 x, and ~0.25x the current MRBD for dairy cattle ). Samples were analyzed for residues of

halosulfuron

- methyl and metabolites determined as the 3

- chlorosulfonamide moiety (3

- CSA) and expressed in parent equivalents. No quantifiable residues (<0.01 ppm) were found in milk, muscle, or fat of cattle at feeding levels of 0.5, 1.5, and 5.0 ppm. Quantifiable residues were found in liver and kidney at all feeding levels. Th e results of the cattle feeding study are summarized in Table 6

.

Table 6 . Maximum Residues of Halosulfuron

- methyl and Metabolites in Dairy Cattle Tissues and Milk.

Dose (ppm) Maximum r esidues of total CSA, expressed as halosulfuron

- methyl equivalents (ppm)

Whole Milk Raw Cream Raw Skim M ilk Muscle Fat Liver Kidney

0.5 NA 1 NA NA NA NA 0.01 0.02

1.5 NA NA NA <0.01 <0.01 0.04 0.11

5.0 <0.01 <0.01 <0.01 <0.01 <0.01 0.11 0.24

1 NA = N ot analyzed

.

To assess the need for tolerances for cattle commodities, t he results of the cattle feeding s tudy are

summarized in Table 7 , reflecting extrapolation of residues found to a 1x feeding leve l for dairy

cattle

.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 17 of 30 Table 7 . Extrapolation of Residues found in the Ruminant Feeding Study to a 1x Feeding Level. 1

Matrix Residues of total CSA, expressed as halosulfuron

- methyl equivalents (ppm)

Feeding level = 0.5 ppm 0.0 25 x MRDB Feeding level = 1 .5 ppm 0.0 75 x MRDB Feeding level = 5 .0 ppm 0.25x MRDB Maximum

expected at

1x Residues

found Expected at

1x Residues

found Expected at

1x Residues

found Expe cted at

1x

Milk

-- -- -- -- < 0.01 < 0.04 < 0.04

Skim milk

-- -- -- -- < 0.01 < 0.04 < 0.04

Cream

-- -- -- -- < 0.01 < 0.04 < 0.04

Liver 0.01 0.40 0.04 0.53 0.11 0.44 0.44

Kidney 0.02 0.79 0.11 1.46 0.24 0.95 0.95

Muscle

-- -- < 0.01 < 0.13 < 0.01 < 0.04 < 0.13

Fat

-- -- < 0.01 < 0.13 < 0.01 < 0.04 < 0.13

1 Based on the MRBD to dairy cattle of 19. 9 ppm

Evaluation of the current dietary burden for dairy cattle in conjunction with the cattle feeding study indicates that expected residues in live r and kidney will incre ase to 0. 44 and 0.95 ppm, respectively, as a result of the proposed use on grass. Residues in milk, skim milk, cream, muscle, and fat were below the LOQ at all dosing levels in the feeding study

. Based on extrapolation from the highest concentration leve l (5 ppm) of the feeding study with residues at the LOQ (0.01 ppm) in milk, muscle, and fat, HED has concluded that tolerances at 0.05 ppm

can be established for residues of halosulfuron

- methyl in the milk, muscle and fat of cattle, goats, horses, and shee p based on the reasons stated in the ChemSAC minutes (ChemSAC 06/20/2012). For future new uses that increase the dietary burden above 20 ppm, a n ew feeding study will be

needed.

Conclusions. The available ruminant feeding study which corresponds to 0. 25x the current MRDB of dairy cattle is acceptable to support the proposed new uses of halosulfur on

- methyl on millet and grasses

. In support of the proposed uses, tolerances need to be established at 0.05 ppm

on milk, muscle, and fat of cattle, goats, hor ses, and sheep. The petitioner must propose a

tolerance of 0.05 ppm on these livestock commodities

. For future new uses that increase the dietary burden above 20 ppm, a new feeding study wil l be needed reflecting dosing at 1x, 3x, and

10x the maximum rea sonable dietary burden (MRDB).

The available data for liver and kidney are sufficient to assess the existing tolerance s for meat byproducts. The data indicate that the established tolerance s of 0.1 ppm for the meat byproducts of cattle, goat, horse, a nd sheep are too low and should be increased to 1. 0 ppm.

No change is needed for the established tolerance of 0.1 ppm for hog meat byproducts.

HED previously concluded (PP#2G4073) that tolerances for halosulfuron

- methyl residues in poultry commoditie s were not required due to low use rates, low residues of halosulfuron

- methyl in poultry feed items, and the low transfer rate of residues to poultry tissues. This conclusion remains unchanged.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 18 of 30 860.1500 Crop Field Trials

DER Reference: 48583601 .der ( P ro so millet )

DER Reference: 48583602 .der ( P asture and rangeland grass)

Canyon Group LLC (agent Gowan Company) submitted magnitude of the residue studies on

proso millet and pasture and rangeland grass. The results from these field trials are discussed

below

, and the residue data are summarized in Table s 8 and 9

.

Proso Millet

Gowan Company has submitted field trial data for halosulfuron

- methyl on proso millet

. Five field trials were conducted in the United States during the 2009 growing season in the Nort h American Free Trade Agreemen t (NAFTA) Growing Zones 5 (NE; 1 trial), 7 (NE and ND; 2 trials), and 8 (KS; 2 trials). Two pairs of trials (Trials

- 01/

- 02 in NE and Trials

- 04/

- 05 in KS) were each conducted by the same principle field investigator. Examin ation of the field trial

records indicates that there were sufficient distinguishing characteristics between the trials in each pair that each trial constitutes a separate trial for purposes of 860.1500 data requirements. For the NE trials, distinguishing characteristics include irrigation (overhead at Trial

- 01 and none

at Trial

- 02), spray volume (>25% difference), distance (>20 miles apart), and NAFTA zone. For the KS trials, distinguishing characteristics include irrigation (subsurface at Trial

- 04 an d none at

Trial

- 05) and distance (~40 miles apart).

Each trial consisted of one untreated plot and one treated plot. At each trial location, the treated plots received a single foliar broadcast application of a 12.5% WG formulation of halosulfuron

met hyl (Yukon Herbicide) at 0.0310

- 0.0314 lb ai /A (0.0347

- 0.0352 kg ai/ha ; ~1x the maximum proposed seasonal application rate )

. The 12.5% WG formulation is a n MAI formulation that also contains 55% dicamba; only data for halosulfuron

- methyl are presented her ein. All applications were made using ground equipment in spray volumes of 10

- 15 gal/A (94

- 140 L/ha). A n NIS was added to the spray mixture for each of the applications for all trials. In addition, the spray

solutions included urea ammonium nitrate ( UAN )

.

Samples of forage were harvested at normal crop maturity at a 0

- day PHI and again at a 7

- day PHI. Hay samples were harvested at a 36

- to 37

- day PHI ; hay was dried in the field for 3

- 8 days prior to collection. Grain and straw samples were harvested at normal crop maturity (51

- to 67

- day PHIs); straw was dried in the field for 2

- 7 days at two trial sites prior to collection. To assess residue decline, additional samples were harvested from one trial in NE (Trial

- 02) at PHIs of 3 and 14 days for for age, 31, 44, and 52 days for hay, and 52, 65, and 72 days for grain and straw.

Samples were analyzed for residues of halosulfuron

- methyl using the tolerance enforcement

method , and the study is supported by adequate storage stability data. The sample sto rage intervals and conditions are presented in Table 4.

The results of the millet crop field trials are summarized in Table 8. Following a single foliar broadcast application of the 12.5% WG formulation at 0.0310

- 0.0314 lb ai/A (0.0347

- 0.0352 kg ai/ha), residues (and per trial averages) of halosulfuron

- methyl in/on proso millet forage

harvested at 0

- and 7

- day PHIs, respectively, were 2.37

- 5.81 (2.42

- 5.04) and 0.0231

- 0.640Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 19 of 30 (0.0261

- 0.634) ppm; residues (and per trial averages) in/on hay (36

- to 37

- day PHIs ) and grain and straw (51

- to 67

- day PHIs) were below the LOQ (<0.01 ppm) in/on all samples.

In the residue decline trial, average residues of halosulfuron

- methyl decreased with increasing PHIs in forage. Residues in hay, grain, and straw were below th e LOQ at all harvest intervals; therefore, residue decline could not be assessed.

Table 8. Summary of Residue Data from Proso Millet Crop Field Trials with Halosulfuron

- methyl.
Commodity Total

Rate

lb ai/A (kg ai/ha) PHI

(days) Residue Levels (ppm) 1

n Sample

Min. Sample

Max. LAFT 2 HAFT 2 Median Mean Std.

Dev.

PROSO MILLET (proposed use = 0.0313 lb ai/A total application rate;

PHIs/PGIs = 0 or 7 days (forage) and 37 days (hay) 3

Forage 0.0310

- 0.0314

(0.0347

- 0.0352) 0 5 2.37 5.81 2.42 5.04 2.76 3.14 1.08

7 5 0.0231 0.640 0.0261 0.634 0.0744 0.179 0.256

Hay 36

- 37 5 <0.01 <0.01 <0.01 <0.01 0.01 0.01 N/A

Grain 51

- 67 5 <0.01 <0.01 <0.01 <0.01 0.01 0.01 N/A

Straw 51

- 67 5 <0.01 <0.01 <0.01 <0.01 0.01 0.01 N/A

1 Except for sample min/max, val ues reflect per trial averages; n = no. of field trials. For calculation of median, mean, and standard deviation, the LOQ (0.01 ppm) was used for any results reported as <LOQ in Table C.3. N/A = Not applicable.

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

3 A PHI/PGI of 0 days and 7 days is proposed for millet forage ( refer to 860.1200 for additional details) ; no PHI has been proposed for grain and straw

.

Conclusions. Pending submission of the deficiencies listed under reg ulatory recommendations

, t he submitted residue data for proso millet are acceptable. The study reflects the maximum proposed use pattern , and t he number and locations of the field trials are in accordance with

OCSPP 860.1500 for proso millet. An acceptab le method was used for residue quantitation, and the data are supported by adequate storage stability data.

The submitted data for proso millet are sufficient for establishing tolerances for millet commodities associated with the proposed use. The data w ill support tolerances at the LOQ of

0.01 ppm for proso millet hay, grain, and straw and at 10 ppm for millet, forage. The tolerance calculations are presented in Appendix I.

Provided the petitioner proposes a PHI of 50 days for millet grain and straw and a PHI of 0

- day for millet forage , the data will support tolerances at the LOQ of 0.01 ppm for proso millet hay, grain, and straw and 10 ppm for proso millet forage

.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 20 of 30 Pasture and Rangeland Grass es

Gowan Company has submitted field trial data for hal osulfuron

- methyl on pasture and rangeland

grasses

. Twelve field trials were conducted in the United States during the 2009 growing season in the NAFTA Growing Zones 1 (PA; 1 trial), 2 (NC; 1 trial), 4 (LA; 1 trial), 5 (MI, WI, IL, and MO; 4 trials), 6 (TX ; 1 trial), and 11 (ID and WA; 4 trials). Four trials each were conducted using Bermuda grass, bluegrass

, and rangeland grass (bromegrass, squirreltail, crested wheatgrass).

Each trial consisted of one untreated plot and one treated plot. At each tria l location, the treated plots received a single foliar broadcast application of a 12.5% WG formulation of halosulfuron

methyl (Yukon Herbicide) at 0.0622

- 0.0651 lb ai/A (0.0697

- 0.0730 kg ai/ha ; ~1x the maximum proposed seasonal application rate )

. The 12.5 % WG formulation is a n MAI formulation that also contains 55% dicamba; only data for halosulfuron

- methyl are presented herein. All applications were made using ground equipment in spray volumes of 10

- 15 gal/A (94

- 140 L/ha). A n NIS was added to the spray mixture for each of the applications for all trials.

Samples of forage were harvested at normal crop maturity (6

- inch to early boot stage) at a 0

- day PHI and again at a 6

- to 7

- day PHI. Hay samples were harvested at a 23

- to 37

- day PHI ; hay was

dried in the field for 1

- 9 days prior to collection. To assess residue decline, additional samples were harvested from one trial at PHIs of 3 and 14 days for forage and at PHIs of 25, 38, and 47 days for hay.

Samples were analyzed for residues of halosulfuron

- methyl using the tolerance enforcement method, and the study is supported by adequate storage stability data. The sample storage intervals and conditions are presented in Table 4.

The results of the grass field trials are summarized in Table 9. Followin g a single foliar broadcast application of the 12.5% WG formulation at 0.0622

- 0.0651 lb ai/A (0.0697

- 0.0730 kg ai/ha), residues (and per trial averages) of halosulfuron

- methyl in/on grass forage harvested at 0

- and 6

- to 7

- day PHIs, respectively, were 3.06

- 11.2 (3.24

- 11.0) and 0.0252

- 4.89 (0.0269

- 4.57) ppm; residues (and per trial averages) in/on hay (23

- to 37

- day PHIs) were <0.01

- 0.389 (<0.01

- 0.384) ppm. HED note s that the highest residues in hay (average 0.384 ppm) were observed in samples collected fro m Trial 01 at a 23

- day PHI; average residues in samples from the remaining trials (PHIs of 31

- 37 days) were <0.01

- 0.0473 ppm.

In the residue decline trial, average residues of halosulfuron

- methyl decreased with increasing PHIs in grass forage and hay.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 21 of 30 T able 9

. Summary of Residue Data from Pasture and Rangeland Grass Crop Field Trials with

Halosulfuron

- methyl.
Commodity Total

Rate

lb ai/A (kg ai/ha) PHI

(days) Residue Levels (ppm) 1

n Sample

Min. Sample

Max. LAFT 2 HAFT 2 Median Mean Std.

Dev.

PASTUR E AND RANGELAND GRASSES (proposed use = 0.0 625 lb ai/A total application rate;

PHIs/PGIs = 0 or 14 days (forage) and 37 days (hay) 3

Grass forage 0.0622

- 0.0651

(0.0697

- 0.0730) 0 12 3.06 11.2 3.24 11.0 6.52 6.66 2.69

6

- 7 12 0.0252 4.89 0.0269 4.57 0.972 1.46 1.50

Grass hay 23

- 37 12 <0.01 0.389 <0.01 0.384 0.0329 0.0702 0.109

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 (0.01 ppm) was used for any results reported as <LOQ in Table C.3.

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

3 Per OCSPP 860.1000 Table 1, a 0

- day PHI/PGI is required for grass forage.

Conclusions. The submitted residue data for pasture an d rangeland grasses are acceptable. The study reflects the maximum proposed use pattern for pasture and rangeland grasses , and t he

number and locations of the field trials are in accordance with OCSPP 860.1500 for c rop g roup 17, grass forage

, fodder

, and hay. An acceptable method was used for residue quantitation, and the data are supported by adequate storage stability data.

HED note s that the petitioner has proposed 0

- and 14

- day PHI/PHIs for forage ; however, p er Table 1 in OCSPP 860.1000, a 0

- day PHI/ PGI is required for grass forage . T herefore, the tolerance for grass forage must be based on the 0

- day data.

The submitted data for grasses are sufficient for establishing tolerances for grass commodities associated with the proposed use. The availabl e field trial data will support tolerances of 20 ppm for grass for age and 0.5 0 ppm for grass hay. The tolerance calculations are presented in Appendix I.

860.1520 Processed Food and Feed

There are no proposed uses that are relevant to this guideline top ic.

860.1650 Submittal of Analytical Reference Standards

An analytical standard is currently available in the EPA National Pesticide Standards Repository

for halosulfuron

- methyl (expiration 4/21/2014 ) and the metabolite chlorosulfon amide acid (expiration 6/21/2016) ; however, a standard is not available for the rearrangement ester (RRE; 1

- H

- pyrazole

- 4

- carboxylic acid, 3

- chloro

- 5

- [(4,6

- dimethoxy

- 2

- pyrimidinyl)amino]

- 1

- methyl, methyl ester) (personal communication with Theresa Cole , ACB

, 3/6/2012 ). A standard for the

RRE of halosulfuron

- methyl is required in support of the tolerance enforcement method for plant commodities. The analytical reference standard of the RRE must be supplied and supplies replenished as requested by the Reposi tory.

The reference standards should be sent to the Analytical Chemistry Lab, which is located at Fort Meade, Maryland. They can be sent to the attention of either Theresa Cole or Thuy Nguyen atHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 22 of 30 the address listed below. The full 9

- digit zip code is m andatory or the mail will be returned to the registrant.

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

- 5350

The letter of transmittal should include the assay of the standards , names of the analytical methods used, a statement of principal impurities, purification procedures employed, storage requirements, and special precautions for safe handling. Replacement of standards may be required periodically if supplies are exhausted or if decomposition occurs during storage. Material Safety Data Sheets (MSDSs) must accompany all analytical standards as specified by Occupational Safety and Health Administration (OSHA) in 29 CFR 1910.1200.

860.1850 and 860.1900 Confined /Field Accumu lation in Rotational Crops

DP# 225273 , G.J. Herndon

, 10 / 29 / 19 9 8 Metabolism Committee decision, G . Herndon

, 5/21/ 19 96

DP# 192510, G. Kramer , 8/30/1993

DP# s 188144 and 188814 , G. Herndon , 3/11/ 19 93

Acceptable confined rotational and limited field rotation al crop studies were previously submitted. The results of both studies indicate that metabolites containing the pyrazole moiety may accumulate in harvested crops planted at intervals greater than one year. The confined rotational crop study, conducted at 0.19 lb ai/A, indicated that no measurable residues of

halosulfuron

- methyl were detected in any rotational crop commodities of wheat, soybean, radish and lettuce at any plantback interval (30, 120, and 360 days after treatment). The limited field

rotatio nal crop study, conducted at 0.22 lb ai/A in a split (preplant + postemergence) application, with rotated crops of winter wheat, spring wheat, soybean, sugar beet, and leaf lettuce indicated

that no measurable residues of halosulfuron

- methyl were detected in any field rotational crop samples, except in one spring wheat forage sample at 0.090 ppm (364

- day plantback interval).

HED previously concluded that the residue of concern in rotational crops is halosulfuron

- methyl. Based on the absence of the parent compound in the confined studies and in the limited field rotational crop studies, with the exception of one forage sample, HED previously concluded that rotational crop tolerances and restrictions are not required for halosulfuron

- methyl.

Conclusion. Th e proposed use s on proso millet and rice will not alter HED’s earlier assessment regarding the potential for inadvertent residues in rotat able crops addressed in this registration

action . No additional data are required.

860.1550 Proposed Tolerances

T olerances are established under §180.479(a)(2) for residues of halosulfuron

- methyl in/on plant commodities, to be determined by measuring only halosulfuron

- methyl. The proposed tolerance expression is consistent with the established tolerances

.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 23 of 30 Adequate f

ield trial data reflecting the proposed use patterns are available for purposes of establishing tolerances for proso millet for all commodities except millet forage

, and for grass forage and hay.

Residues in/on proso millet hay, grain, and straw were be low the LOQ; the available data will
support tolerances at the LOQ of 0.0 1 ppm for these commodities. These tolerances are in agreement with the proposed tolerances for grain and straw ; however, the proposed tolerance for hay was 0.02 ppm

. T he difference in the proposed and recommended tolerance s for millet hay

are due to the petitioner having used residue values below the LOQ and t he NAFTA tolerance calculation procedures in determining the hay tolerance

.

Residues of h alosulfuron

- methyl were quantifia ble in/on proso millet forage, grass forage

, and grass hay ; therefore, the OECD tolerance calculation procedures were utilized in determining appropriate tolerance level s for these commodities . The tolerance calculations are presented in Appendix I. Usin g the OECD tolerance calculation procedures, the recommended tolerances are: 10 ppm (0

- day PHI) and 1.5 ppm (7

- day PHI) for millet forage, 20 ppm for grass forage and 0.5 ppm for grass hay. HED recommend s a tolerance of 10 ppm for millet forage based on residue data using 0

- day PHI. The proposed tolerances are too low for grass forage and too high for grass hay. T he difference s in the proposed and recommended tolerance s for these commodities

are due to the petitioner having used the NAFTA tolerance cal culation procedures in determining the proposed tolerance s.

In conjunction with the proposed uses on proso millet and grasses, HED has updated the dietary

burden calculations for ruminants and has conclude d that tolerances at 0.05 ppm are needed for

resi dues of halosulfuron

- methyl in the milk, muscle and fat of cattle, goats, horses, and sheep. The petitioner must propose a tolerance of 0.05 ppm for these livestock commodities

. The available feeding study data indicate that the established tolerances of 0.1 ppm for the meat byproducts of cattle, goat, horse, and sheep are too lo w and should be increased to 1.0 ppm.

There are no Codex, Canadian, or Mexican maximum residue limits (MRLs) established for

residues of halosulfuron

- methyl in /on crop or lives tock commodities. An International Residue Limit (IRL) form is appended to this Summary Document as Appendix I I

.

Tolerances related to this action are summarized in Table 10

.

Table 10 . Tolerance Summary for Halosulfuron

- Methyl.
Commodity Propose d /Existing Tolerance (ppm) Recommended

Tolerance (ppm) Comments; Correct Commodity

Definition

Millet, proso, forage 7.0 10 The data s upport s a tolerance of 10 ppm

with a 0

- day PHI/PGI.

Millet, proso, hay 0.02 0.01

Millet, proso, grain 0.01 0.01

Mille t, proso, straw 0.01 0.01Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 24 of 30 Table 10 . Tolerance Summary for Halosulfuron

- Methyl.

Commodity Propose d /Existing Tolerance (ppm) Recommended

Tolerance (ppm) Comments; Correct Commodity

Definition

Grass forage, fodder, and hay, Crop group 17 forage 17 20 Grass

, forage, fodder, and hay, group 17, forage

Grass forage, fodder, and hay, Crop group 17 hay 0.90 0.5 Grass, forage, fodder, and hay, group 17, hay

Additional Live stock Commodity Tolerances That Need to be Proposed/Established

Cattle, meat byproducts 0.1 1 .0

Goat, meat byproducts 0.1 1. 0

Horse, meat byproducts 0.1 1. 0

Sheep, meat byproducts 0.1 1. 0
Additional Livestock Commodity Tolerances That Need to be P roposed/Established

Cattle, fat None 0.05

Cattle, meat None 0.05

Goat, fat None 0.05

Goat, meat None 0.05

Horse, fat None 0.05

Horse, meat None 0.05

Milk None 0.05

Sheep, fat None 0.05

Sheep, meat None 0.05

A ttachments: Appendix I: Tolerance Assessment Calculations Appendix II: International Residue Limit sHalosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 25 of 30 

### Appendix I

Tolerance Assessment Calculations

T he OECD tolerance calculation procedures (March 2011 version) were used for calculating

recommended tol erances for proso millet (forage) and pasture and rangeland grasses (forage and hay ). The statistical goal of the OECD tolerance calculation procedures is to produce an MRL proposal in the region of the 95 th percentile of the underlying residues distribut ion. The average residue values used to calculate the tolerances are provided in Table I

- 1.

Table I

- 1. Residue data used to calculate tolerances for h alosulfuron

- methyl

. Regulator: EPA

Chemical: H alosulfuron

- methyl

Crop: Proso Millet, Forage Grass, Forage Grass, Hay

PHI: 0 days 7 days 0 days 37 days

App. Rate: 0.031 lb ai/A 0.0625 lb ai/A

Submitter: Gowan Gowan

MRID Citation: 48583601 48583602

H alosulfuron

- methyl Residues (ppm)

5.04 0.634 8.94 0.384

2.50 0.0662 4.09 0.0433

2.76 0.0935 3.2 4 0.01 *

2.99 0.0744 11.0 0.0184

2.42 0.0261 10.1 0.0443

6.57 0.01 *

4.11 0.0348

9.63 0.183

3.75 0.01 *

5.47 0.0309

6.53 0.0265

6.50 0.0473

*censored values

Proso Millet

The dataset used to establish a tolerance for h alosulf uron

- methyl on proso millet forage consisted

of field trial data on proso millet at application rates of 0.0310

- 0.0314 lb ai/A

, with a 0

- day PHI

and a 7

- day PHI

. The field trial application rates and PHIs are within 25% of the maximum label application ra te and minimum label PHI, respectively. The average residue values used to

calculate the tolerance s are provided in Table I

- 1. R esidues of h alosulfuron

- methyl were quantifiable (LOQ = 0.01 ppm) in/on all samples of forage (0

- and 7

- day PHI). Using the O ECD tolerance calculation procedures, the recommended tolerance is 10 ppm (0

- day PHI)

.Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 26 of 30 Halosulfuron

- methyl

Proso Millet , Forage

USA
0.031 lb ai/A, 0

- day PHI

Total number of data (n) 5

Percentage of censored data 0%

Number of non

- censored data 5

Lowest residue 2.420

Highest residue 5.040

Median residue 2.760

Mean 3.142

Standard deviation (SD) 1.085

Correction factor for censoring (CF) 1.000

Proposed MRL estimate

- Highest residue 5.040

- Mean + 4 SD 7.480

- CF x 3 Mean 9.4 26

Unrounded MRL 9.426

Rounded MRL 10

High uncertainty of MRL estimate.

[Small dataset]Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 27 of 30 Halosulfuron

- methyl

Proso Millet , Forage

USA
0.031 lb ai/A, 7

- day PHI

Total number of data (n) 5

Percentage of censored data 0%

Number of non - censored data 5

Lowest residue 0.026

Highest residue 0.634

Median residue 0.074

Mean 0.179

Standard deviation (SD) 0.256

Correction factor for censoring (CF) 1.000

Proposed MRL estimate

- Highest residue 0.634

- Mean + 4 SD 1.201

- CF x 3 Mean 0.537

Unrounded MRL 1.201

Rounded MRL 1.5

High uncertainty of MRL estimate.

[Small dataset]Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 28 of 30 Pasture and Rangeland Grasses

The dataset used to establish a tolerance for h alosulfuron

- methyl on pasture and rangeland

grasses c onsisted of field trial data on pasture and rangeland grasses at application rates of

0.0622

- 0.0651 lb ai/A, with a 0

- day PHI for forage and 23

- 37

- day PHIs for hay . The field trial application rates and PHIs are within 25% of the maximum label applicatio n rate and minimum label PHI, respectively, with the exception that the PHI for hay at one trial (23 days at Trial

- 01) differed from the target PHI of 37 days by > 25%. The average residue values used to calculate

the tolerance s are provided in Table I

- 1. Residues of h alosulfuron

- methyl were quantifiable (LOQ = 0.01 ppm) in/on all forage samples and in /on samples from 9 of 12 hay sites . Using the OECD tolerance calculation procedures, the recommended tolerance s are 20 ppm for grass, forage and 0.5 0 ppm f

or grass, hay.

Halosulfuron

- methyl

Grass, Forage

USA
0.0625 lb ai/A, 0

- day PHI

Total number of data (n) 12

Percentage of censored data 0%

Number of non

- censored data 12

Lowest residue 3.240

Highest residue 11.000

Median residue 6.515

Mean 6 .661

Standard deviation (SD) 2.687

Correction factor for censoring (CF) 1.000

Proposed MRL estimate

- Highest residue 11.000

- Mean + 4 SD 17.409

- CF x 3 Mean 19.983

Unrounded MRL 19.983

Rounded MRL 20Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 29 of 30 Halosulfuron

- methyl

Grass, Hay

USA
0.0625 lb ai/A, 37

- day PHI

Total number of data (n) 12

Percentage of censored data 25%

Number of non

- censored data 9

Lowest residue 0.010

Highest residue 0.384

Median residue 0.033

Mean 0.070

Standard deviation (SD) 0. 109

Correction factor for censoring (CF) 0.833

Proposed MRL estimate

- Highest residue 0.384

- Mean + 4 SD 0.507

- CF x 3 Mean 0.176

Unrounded MRL 0.507

Rounded MRL 0.5Halosulfuron

- methyl Summary of Analytical Chemistry and Residue Data DP# 393948

Page 30 of 30 

### Appendix I I

International Residue Limits

Halosul furon

- methyl ( 128721 ; 02/29/2012 )

Summary of US and International Tolerances and Maximum Residue Limits Residue Definition :
US Canada Mexico 2 Codex 3

40 CFR 180.479

Plant: Halosulfuron

- methyl, methyl 5

- [(4,6

- dimethoxy

- 2

- pyrimidiny)amino]carbonylaminosul fonyl]

- 3

- chloro

- 1

- methyl

- 1H

- pyrazole

- 4

- carboxylate

Livestock: Halosulfuron

- methyl residues containing

the 3

- chlorosulfonamide (3

- CSA) moiety, expressed as the stoichiometric equivalent of halosulfuron

methyl None None

Commodity 1 Tolerance (ppm) /Maximum Residue Limit (mg/kg)

US Canada Mexico 2 Codex 3

Millet, proso, forage 10 Millet, proso, hay 0.01 Millet, proso, grain 0.01 Millet, proso, straw 0.01 Grass, forage, fodder, and hay, group 17, forage 20

Grass, forage, fodder, and hay, group 17, hay 0.5

Cattle, meat byproducts 1.0 Goat, meat byproducts 1.0 Horse, meat byproducts 1.0 Sheep, meat byproducts 1.0
Cattle, fat 0.05
Cattle, meat 0.05
Goat, fat 0.05
Goat, meat 0.05
Horse, fat 0.05
Horse, m eat 0.05

Milk 0.05 Sheep, fat 0.05 Sheep, meat 0.05 Completed: M. Negussie; 06/21 /2012

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.

3 * = absent at the limit of quantitation; Po = postharvest treatment, such as treatment of stored grains. PoP = processed postharvest treated commodity, such as processing of treate d stored wheat. (fat) = to be measured on the fat portion of the sample. MRLs indicated as proposed have not been finalized by the CCPR and the CAC.