Document ID: EPA-HQ-OPP-2009-0003-0006
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-09-23T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, D.C.  20460

	OFFICE OF PREVENTION, PESTICIDE

	AND TOXIC SUBSTANCES

  SEQ CHAPTER \h \r 1 MEMORANDUM

Date:  4/23/09

SUBJECT:	Halosulfuron-methyl.  Application for Amended Section 3
Registration to Add Uses on Soybeans.  Summary of Analytical Chemistry
and Residue Data.

PC Code:  128721	DP Barcode:  358029

Decision No.:  399588	Registration No.:  81880-2

Petition No.:  8F7424	Regulatory Action:  Amended Section 3 Registration

Risk Assessment Type:  NA	Case No.:  NA

TXR No.:  NA	CAS No.:  100784-20-1

MRID No.:  47527401	40 CFR:  180.479

	

FROM:	Nancy Dodd, Chemist

		Risk Assessment Branch III (RAB3)

		Health Effects Division (7509P)  SEQ CHAPTER \h \r 1 

THROUGH:	Leung Cheng, Senior Chemist

		RAB3/HED (7509P)		

		

TO:		Vickie Walters/James Tompkins (RM Team #25)

		Herbicide Branch

		Registration Division (7505P)

MRID Summary Table

MRID No.	Study Type	Comments

47527401	860.1500/1520 Soybean	New DERs 47527401.de1 (field trials) and
47527401.de2 (processing)

  SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1 

  SEQ CHAPTER \h \r 1 This document was originally prepared under
contract by Dynamac Corporation (1901 Research Boulevard, Suite 220;
Rockville, MD 20850).  The document has been reviewed by the Health
Effects Division (HED) and revised to reflect current Office of
Pesticide Programs (OPP) policies.

Executive Summary

Halosulfuron-methyl [methyl
3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony
l]-1-methyl-1H-pyrazole-4-carboxylate] is a selective herbicide
belonging to the sulfonylurea group of herbicides, which inhibits the
action of acetolacetate synthase enzyme, a specific plant enzyme. 
Halosulfuron-methyl is used for the pre- and postemergence control of
annual broadleaf weeds and nutsedges in selected crops, as well as
residential turf grass and ornamentals, and is formulated as a dry
flowable/water-dispersible granule formulation.    

The Canyon Group LLC, a joint venture formed by Gowan Company and Nissan
Chemical Industries (NCI), is proposing to amend the use pattern for the
75% water-dispersible granule (WG) formulation of halosulfuron-methyl
(GWN-3061 Herbicide, EPA Reg. No. 81880-2) to add uses on soybeans. 
Postharvest (fall burndown) application to soybean, and
preplant/preemergence and early postemergence foliar application to
sulfonylurea-tolerant soybean varieties are proposed at a maximum
application rate of 0.062 lb ai/A.  A 30-day pregrazing/preharvest
(PGI/PHI) interval is proposed for soybean forage and silage. 

In conjunction with the requested amended use, the Canyon Group has
submitted a petition, PP#8F7424, to propose the establishment of a
permanent tolerance for residues of the herbicide halosulfuron-methyl
[methyl
3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyraz
ole-4-carboxylic acid], expressed as parent equivalents, in/on the
following raw agricultural commodity:

soybean 	0.05 ppm

Permanent tolerances are established under §180.479(a)(1) for residues
of halosulfuron-methyl and its metabolites determined as
3-chloro-1-methyl-5-sulfamoylpyrazole-4-carboxylic acid, expressed as
halosulfuron-methyl equivalent in/on the meat byproducts of cattle,
goat, hog, horse, and sheep at 0.1 ppm.  Tolerances are established
under §180.479(a)(2) for residues of halosulfuron-methyl in/on a
variety of field, fruit, and vegetable crop commodities, at levels
ranging from 0.05 to 2.0 ppm.  A time-limited tolerance for sweet potato
established under §180.479(b) has expired (expiration data 12/31/08).  

The nature of the residue in plants has been adequately delineated based
on acceptable metabolism studies with corn, sugarcane, and soybean
treated both pre- and postemergence.  HED has concluded that the residue
of concern in plants is halosulfuron-methyl.

The nature of the residue in livestock has been adequately delineated
based on metabolism studies with goats and hens.  HED has concluded 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) 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
that tolerances for halosulfuron-methyl residues in poultry commodities
were not required

due to low use rates, low residues of halosulfuron-methyl in poultry
feedstuffs, and the low transfer rate of residues to poultry tissues.

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).  The plant
method determines halosulfuron-methyl as its rearrangement ester (RRE),
and the livestock method converts residues of halosulfuron-methyl and
metabolites containing the 3-CSA moiety to 3-CSA for determination. 
Samples from the submitted soybean field trial and processing studies
were analyzed for residues of halosulfuron-methyl using a modified
version of the plant enforcement method with a petitioner-validated LOQ
of 0.01 ppm.  A Biological and Economic Analysis Division (BEAD/EPA)
method validation for Method RES-109-97-4 (MRID 44495801) in rice straw,
sugar cane, milo grain, field corn grain, cotton gin byproducts, and
almond nutmeats indicated a quantitation limit of 0.05 ppm (DP#250584,
G. Jeffrey Herndon, 10/28/98).

 

Residues of halosulfuron-methyl and 3-CSA are not adequately recovered
by FDA Multiresidue Method protocols.

Adequate storage stability data are available for halosulfuron-methyl on
soybeans to support the storage conditions and intervals of soybean seed
samples collected from the field trial and processing studies. 
Processed soybean samples were stored <30 days from collection to
analysis; therefore, supporting storage stability data are not required
for these matrices.  

The livestock feedstuffs associated with the proposed use on soybeans
are seed, forage/silage, hay, aspirated grain fractions, meal, and
hulls.  No data were submitted for soybean forage or hay.  No data are
required for aspirated grain fractions since the use is an early season
use. Provided the petitioner amends the proposed label to prohibit the
grazing or feeding of treated soybean forage/silage and hay, the
inclusion of the applicable soybean feed items (seed, meal, and hulls)
would not increase the dietary burdens expected from the currently
registered uses on alfalfa, corn, and sorghum, and therefore, no changes
to the existing livestock commodity tolerances are required.  

Provided the petitioner revises the proposed use pattern to prohibit the
grazing or feeding of treated soybean forage/silage and hay, to specify
a maximum of one application per year at the maximum application rate of
0.062 lb ai/A/year, and to specify a preharvest interval of 88 days for
soybean seed, the submitted field trial data for soybean seed are
adequate to support the proposed tolerance of 0.05 ppm for soybean seed.
 Residues of halosulfuron-methyl were nonquantifiable (<0.01 ppm) in/on
soybean seed samples harvested 88-133 days following treatment of
sulfonylurea-tolerant soybean plants at the V3-V4 (BBCH 13-14) growth
stage with a 75% WG formulation of halosulfuron-methyl at 0.060-0.064 lb
ai/A (approximately 1x the maximum proposed postemergence application
rate).  

No residue data were provided for soybean forage, hay, or aspirated
grain fractions.  If the petitioner wishes to support a 30-day PGI/PHI
for soybean forage/silage and hay, additional residue data will be
required for soybean forage and hay harvested 30 days after a single
postemergence application of the 75% WG at the maximum proposed
application rate to soybean at the V4 growth stage.  Residue data for
aspirated grain fractions are not required because the proposed
postemergence application is an early season use.  

The submitted soybean processing study reflecting postemergence
application at 5x the maximum proposed application rate is adequate. 
Residues of halosulfuron-methyl were <LOQ in soybean seed, meal, hulls,
and refined oil.  No separate tolerances are required for the processed
commodities of soybean.

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

There are no Codex, Canadian, or Mexican maximum residue limits (MRLs)
established for residues of halosulfuron-methyl in/on soybean matrices. 

  SEQ CHAPTER \h \r 1 Regulatory Recommendations and Residue Chemistry
Deficiencies

HED has examined the residue chemistry database for halosulfuron-methyl.
 Pending submission of a revised Section B (see requirements under
Direction for Use) and a revised Section F (see requirements under
Proposed Tolerances) and submission of a reference standard for the RRE
of halosulfuron-methyl (see requirements under Submittal of Analytical
Reference Standards), there are no residue chemistry issues that would
preclude granting a Section 3 registration for the requested uses on
soybean, or the establishment of a tolerance for residues of the
herbicide  halosulfuron-methyl, methyl
3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony
l]-1-methyl-1H-pyrazole-4-carboxylate, as follows:

Soybean, seed	0.05 ppm

A human health risk assessment is forthcoming.

860.1200 Directions for Use

The petitioner must revise the proposed Section B/label to specify a
maximum of one application per year at the maximum application rate of
0.062 lb ai/A/year since the field trial residue data reflect one
application at approximately 0.062 lb ai/A/year.                        
 

Although the postemergence application is restricted to the vegetative
V4 stage (4th trifoliate), prior to flowering/pod formation, a
preharvest interval for soybean seed must be stated.  Based on the
available field trial data, the petitioner must revise the proposed
Section B/label to establish a preharvest interval for soybean seed of
88 days.

The petitioner must revise the proposed Section B/label to prohibit the
grazing or feeding of treated soybean forage/silage and hay since no
residue data were provided for soybean forage and hay.

860.1500 Crop Field Trials

If the petitioner wishes to support a 30-day PGI/PHI for soybean
forage/silage and hay,  residue data will be required for soybean forage
and hay harvested at a 30-day preharvest interval. 

  SEQ CHAPTER \h \r 1 860.1650 Submittal of Analytical Reference
Standards

Analytical reference standards for the 3-CSA (3-chlorosulfonamide acid)
metabolite and the rearrangement ester (RRE) of halosulfuron-methyl must
be submitted to the EPA National Pesticide Standards Repository.  

860.1550 Proposed Tolerances

The petitioner must submit a revised Section F to revise the proposed
tolerance expression for halosulfuron-methyl to be the same as the
Chemical Abstracts Service (CAS) nomenclature (i.e., methyl
3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony
l]-1-methyl-1H-pyrazole-4-carboxylate) and to remove the phrase “and
expressed as parent equivalents” which is not needed for a tolerance
for the parent only.

The petitioner must submit a revised Section F to propose a tolerance
for soybean, seed instead of soybean.

Background

The chemical structure and nomenclature 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 Nomenclature.

Chemical structure	

Common name	halosulfuron-methyl

Company experimental name	MON 12000, NC-319

IUPAC name	methyl
3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyraz
ole-4-carboxylate

CAS name	methyl
3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony
l]-1-methyl-1H-pyrazole-4-carboxylate

CAS registry number	100784-20-1

End-use product (EP)	75% WG (GWN-3061 Herbicide; EPA Reg. No. 81880-2)

Chemical structure of

3-chlorosulfonamide moiety (3-CSA)	

3-chloro-1-methyl-5-sulfamoyl-1H-pyrazole-4-carboxylic acid

Table 2.	Physicochemical Properties of Halosulfuron-methyl.

Parameter	Value	Reference

Melting point/range	175.5-177.2 ºC	MRID 42139403; DP#s 173627 & 180565,
7/30/92, G.J. Herndon

pH	4.11 at 25 ºC (1% w/v slurry)

	Density	1.618 g/mL at 25 ºC

	Water solubility at 20 ºC	pH 5	0.0015 g/100 mL

pH 7	0.165 g/100 mL

pH 9	0.747 g/100 mL

	Solvent solubility at 20 ºC	methanol	0.1616 g/100 mL

n-hexane	0.001278 g/100 mL

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

	Dissociation constant, Ka	3.61 x 10-4 at 22.4 ºC

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

-0.0186 at pH 7

-0.542 at pH 9

	UV/visible absorption spectrum	Not available

	

860.1200 Directions for Use

A supplemental label (undated) for a 75% WG formulation of
halosulfuron-methyl (GWN-3061 Herbicide; EPA Reg. No. 81880-2) with uses
on soybeans was provided, along with a copy of the current accepted
master label dated 10/17/2007.  The proposed use directions from the
GWN-3061 Herbicide supplemental label are summarized in Table 3.



Table 3.	Summary of Directions for Use of Halosulfuron-Methyl.

Applic. Timing, 

Type, and Equip.	Applic. Rate 

(lb ai/A)	Max. No.

Applic. per

Season	Max. Seasonal

Applic. Rate

(lb ai/A)	PHI	Use Directions and Limitations1

Soybean

Postharvest, burndown (fall),

Broadcast,

Ground or air	0.031-0.062	Not specified (NS)	NS	NS	Application is to be
made in the fall after harvest, prior to ground freeze.  For control of
broadleaf weeds, a COC (1-2% v/v) and granular AMS (2-4 lb/A) or UAN
(1-2% v/v) should always be added.  Tank-mix partners include 2,4-D
amine, 2,4-D LV  ester, tribenuron-methyl, thifensulfuron-methyl,
glyphosate (for emerged grass weeds), or any other herbicide with
registration for fall application.  

Preemergence or Preplant (spring);

Broadcast,

Ground or air	0.031-0.062	NS	NS	NS	Application is to be made to soybean
varieties tolerant to sulfonyl-urea herbicides only, 21 days prior to
planting up to preemergence (cracking) of soybeans.  For control of
broadleaf weeds, a COC (1% v/v) and granular AMS (2-4 lb/A) or UAN (1-2%
v/v) should always be added.  Tank-mix partners include glyphosate,
2,4-D LV ester, and thifensulfuron-methyl (7-21 days preplant).  

Postemergence;

Broadcast,

Ground or air	0.031-0.062	NS2	NS	30 days before grazing or harvest of
forage or silage	Application is to be made to soybean varieties tolerant
to sulfonyl-urea herbicides only, at the V2 to V4 growth stage.  An NIS
or COC and granular AMS (2-4 lb/A) or UAN (1-2% v/v) should always be
added.  Tank-mix partners include glyphosate (if soybean variety is also
glyphosate tolerant), thifensulfuron-methyl, and other registered
postemergence soybean herbicides unless specifically restricted by those
product labels.

1  The supplemental label includes the following statements for all
application types:  “All applicable directions, restrictions and
precautions on the EPA registered [master] label are to be followed. 
Refer to “TIME INTERVAL BEFORE PLANTING” table on the EPA-registered
label.”  COC = crop oil concentrate; NIS = nonionic surfactant; AMS =
ammonium sulfate fertilizer; and UAN = urea ammonium nitrate solution
(fertilizer).

2  The label states that, for heavy infestations of nutsedge, sequential
applications may be required.

The master label includes the following additional directions relevant
to the proposed use pattern:  (1) ground applications are to be made in
a minimum of 10 gal/A of water, and aerial applications are to be made
in 3-15 gal/A of water; and (2) application through any type of
irrigation system is prohibited.  

Plantback restrictions are also specified on the master label for a
number of crops, ranging from 0 months for sugarcane and
insecticide-/imidazolidone- resistant field corn to 36 months for sugar
beet in ND, MN, and the Red River Valley.  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 proposed use directions for the 75% WG formulation
must be revised based on the available residue data.  The submitted
field trial data reflect a single postemergence foliar broadcast
application at 0.0603-0.0639 lb ai/A, with soybean seed harvested at
PHIs of 88-133 days.  No residue data were provided for soybean forage
and hay.  The proposed use directions for the 75% WG formulation must be
revised as follows:

The petitioner must revise the proposed Section B/label to specify a
maximum of one application per year at the maximum application rate of
0.062 lb ai/A/year since the field trial residue data reflect one
application at approximately 0.062 lb ai/A/year.                        
 

Although the postemergence application is restricted to the vegetative
V4 stage (4th trifoliate), prior to flowering/pod formation, a
preharvest interval for soybean seed must be stated.  Based on the
available field trial data, the petitioner must revise the proposed
Section B/label to establish a preharvest interval for soybean seed of
88 days.

The petitioner must revise the proposed Section B/label to prohibit the
grazing or feeding of treated soybean forage/silage and hay since no
residue data were provided for soybean forage and hay.

860.1300 Nature of the Residue - Plants

Residue Chemistry Memo DP# 251007, 12/10/98, M. Doherty (PP#8F4937)

Residue Chemistry Memo, No DP#, 5/21/96, G.J. Herndon (Metabolism
Committee decision)

Residue Chemistry Memo DP# 198361, 7/21/94, G. Otakie (PP#4G4279)

Residue Chemistry Memo DP#s 173627 & 180565, 7/30/92, G.J. Herndon
(PP#2G4073)

The nature of the residue in plants is adequately understood based on
acceptable metabolism studies with corn, sugarcane, and soybean; all
studies investigated pre- and postemergence uses.  The metabolism of
halosulfuron-methyl was similar in the three tested crops but dependent
on the mode of application (pre- or postemergence).  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. 

  SEQ CHAPTER \h \r 1 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 previously
concluded that the residue of concern in plants is the parent compound,
halosulfuron-methyl.

 

860.1300 Nature of the Residue - Livestock

Residue Chemistry Memo DP# 223801, 11/17/98, M. Doherty (PP#6F4661)

Residue Chemistry Memo, No DP#, 5/21/96, G.J. Herndon (Metabolism
Committee decision)

Residue Chemistry Memo DP# 204062, 6/22/94, G.J. Herndon (PP#3F4193)

Residue Chemistry Memo DP# 184435, 1/15/93, G.J. Herndon (PP#2G4073)

Residue Chemistry Memo DP# 181023, 11/12/92, G.J. Herndon 

Residue Chemistry Memo DP#s 173627 & 180565, 7/30/92, G.J. Herndon
(PP#2G4073)

Acceptable livestock metabolism studies conducted on goats and hens were
previously submitted 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.

As HED previously concluded, 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-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 rates, low residues of halosulfuron-methyl in poultry
feed items, and the low transfer rate of residues to poultry tissues. 
The inclusion of poultry feed items from soybeans (seed and meal, as
indicated in Table 1 Feedstuffs, June 2008) will not increase the
dietary burdens expected from the currently registered uses on alfalfa,
corn, and sorghum; therefore, HED continues to conclude that tolerances
for poultry commodities are not required. 

860.1340 Residue Analytical Methods

Residue Chemistry Memo DP# 250584, 10/28/98, G.J. Herndon (PP#s 6F4620 &
8F4937)

Residue Chemistry Memo DP# 214890, 5/3/95, G.J. Herndon (PP#3F4193)

Residue Chemistry Memo DP# 202131, 10/4/94, G.J. Herndon (PP#3F4193)

Plants

Enforcement method:  An adequate analytical method is available for
enforcement of tolerances for halosulfuron-methyl residues in plants. 
The GC method quantifies halosulfuron-methyl as its RRE
(1-H-pyrazole-4-carboxylic acid,
3-chloro-5-[(4,6-dimethoxy-2-pyrimidinyl)amino]-1-methyl, methyl ester)
using thermionic-specific detection (TSD, nitrogen specific).  Monsanto
Analytical Method RES-109-97-4 (MRID 44495801) has been validated as an
enforcement method by the Analytical Chemistry Branch (ACB)/BEAD.  The
limit of quantitation on rice straw, sugarcane, milo grain, field corn
grain, cotton gin byproducts, and almond nutmeats was estimated to be
0.05 ppm (DP#250584, G. Jeffrey Herndon, 10/28/98).  

 

Rearrangement ester (RRE) of halosulfuron-methyl

Data collection method:  Samples from the soybean field trial and
processing studies associated with the subject petition 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
partitioned 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 halosulfuron-methyl residues
to the 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.  The
eluate was evaporated to dryness and redissolved in 50% ethyl
acetate/isooctane for analysis by gas chromatography with flame
photometric detection (GC/FPD).  Residues were expressed in terms of
halosulfuron-methyl.  The GC/FPD method was adequate for data collection
based on acceptable method validation and concurrent method recoveries. 
The petitioner-validated LOQ was 0.01 ppm for soybean seed, meal, hulls,
and refined oil.

Conclusions.  The residue analytical methods data are adequate to
satisfy data requirements for the subject action.  Acceptable
enforcement methodology is available for tolerance enforcement purposes
for residues in/on crop commodities, and residues of halosulfuron-methyl
in/on soybean commodities from the crop field trial and processing
studies were determined using an acceptable data collection method.

Livestock

Enforcement method:  An adequate analytical method is available for
enforcement of tolerances for secondary residues of halosulfuron-methyl
in livestock 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, which is extracted with ACN/DCM and then methylated with
trimethylsilyl-diazomethane.  The methyl ester is analyzed by GC with
electron-capture detection (ECD) after cleanup with an alumina/carbon
column.  The petitioner-validated LOQ was 0.01 ppm.  The method has been
validated as an enforcement method by the Analytical Chemistry Branch
(ACB)/BEAD at a limit of quantitation of 0.01 ppm in milk and liver (D.
Swineford, No DP#, 4/28/95).

  860.1360 Multiresidue Methods

Residue Chemistry Memo DP# 189198, 3/8/94, G.J. Herndon (PP#3F4193)

Adequate multiresidue method data for halosulfuron-methyl and 3-CSA were
submitted previously in 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

Residue Chemistry Memo DP# 189198, 3/8/94, G.J. Herndon (PP#3F4193)

Adequate storage stability data were previously submitted (DP#243050, M.
Doherty, 1/5/99)  indicating that halosulfuron-methyl is stable in corn
grain stored frozen for up to 823 days (27 months) and in soybeans,
wheat, lettuce, and sugar beets stored frozen for up to 996 days (33
months).  

Samples from the soybean field trial and processing studies were stored
frozen (~-20 ºC) from harvest/processing to analysis for up to 190 days
(6.2 months) for soybean seed and 20-21 days (0.7 months) for soybean
meal, hulls, and refined oil.  No new storage stability data were
provided to support the studies.

Conclusions.  The available storage stability data for soybeans are
adequate to support storage conditions and durations of seed samples
from the soybean field trial and processing studies.  Processed soybean
samples were stored <30 days from collection to analysis; therefore,
supporting storage stability data are not required for these matrices.

860.1400 Water, Fish, and Irrigated 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

Residue Chemistry Memo DP# 189198, 3/8/94, G.J. Herndon (PP#3F4193)

Residue Chemistry Memo DP#s 173627 & 180565, 7/30/92, G.J. Herndon
(PP#2G4073)

The livestock feedstuffs associated with the proposed use on soybean are
seed, forage/silage, hay, aspirated grain fractions, meal, and hulls. 
No data were submitted for soybean forage or hay; however, soybean
forage/silage and hay are considered to be under grower control so label
restrictions are allowed for these commodities.  No data were submitted
and none are required for aspirated grain fractions since the proposed
use is an early season use pattern. 

An adequate dairy cattle feeding study was reported in conjunction with
PP#3F4193; in this same review, HED determined that tolerances were not
required for halosulfuron-methyl in poultry commodities.  

Conclusion.  Provided the petitioner amends the proposed label to
prohibit the grazing or feeding of treated soybean forage/silage and
hay, the inclusion of the applicable livestock feed items from soybeans
(seed, meal, and hulls) would not increase the dietary burden expected
from the currently registered uses on alfalfa, corn, and sorghum. 
Therefore, HED continues to conclude that tolerances for poultry
commodities are not required and the existing livestock tolerances (0.1
ppm for meat byproducts of cattle, goat, hog, horse and sheep) are
adequate. If the petitioner intends to support a 30-day PGI/PHI for
soybean forage and hay, the dietary burdens for livestock will be
re-evaluated when the additional field trial data become available.

860.1500 Crop Field Trials

DER Reference:  47527401.de1.doc

The petitioner has submitted field trial data for halosulfuron-methyl
with sulfonylurea-tolerant soybeans.  Twenty soybean field trials were
conducted in Zones 2 (NC, SC; 2 trials), 4 (AR, LA; 3 trials) and 5 (IA,
IL, IN, MN, MO, NE, OH; 15 trials) during the 2007 growing season. 

One untreated and one treated plot were established at each trial site. 
A single foliar broadcast application of a 75% WG formulation of
halosulfuron-methyl was made to sulfonylurea-tolerant soybean plants at
the V3 to V4 growth stage, at a target rate of 0.062 lb ai/A (1x the
proposed postemergence use on sulfonylurea-tolerant soybean). 
Applications were made using ground equipment in spray volumes of 5-20
gal/A, with a COC (5 trials) or an NIS (15 trials) added to the spray
mixture.  Mature soybean seed was harvested at PHIs of 88-133 days.  To
investigate residue decline, additional soybean seed samples were
collected from two trials 7 days prior to, and 6-7 and 14 days after the
target harvest date.

Samples of soybean seed were analyzed for residues of
halosulfuron-methyl as its RRE using the available tolerance enforcement
method, Method RES-109-97-4, with modifications.  The LOQ was 0.01 ppm. 
Sample storage intervals and conditions are reported under OPPTS
860.1380.  Adequate storage stability data are available to support the
study.

The results of the soybean seed field trials are summarized in Table 4. 
Residues of halosulfuron-methyl were nonquantifiable (<0.01 ppm) in/on
all samples of sulfonylurea-tolerant soybean seed harvested 88-133 days
following a single foliar broadcast application of the 75% WG
formulation of halosulfuron-methyl, made early postemergence (V3-V4) at
0.0603-0.0639 lb ai/A.



Table 4.	Summary of Residue Data from Crop Field Trials with
Halosulfuron-methyl.

Crop matrix	Total Applic. Rate

 (lb ai/A)	PHI (days)	Residue Levels (ppm)

	n	Min.	Max.	HAFT1	Median	Mean	Std. Dev.2

SOYBEAN (proposed use = fall burndown, preplant/preemergence, or
postemergance at 0.062 lb ai/A application rate, 30-day PHI/PGI for
forage and silage)

Soybean seed	0.0603-0.0639	88-133	40	<0.01	<0.01	<0.01	0.01	0.01	NA

1  HAFT = Highest Average Field Trial.

2  Standard deviation is not applicable (NA) when all residues are below
the method LOQ.

Conclusions.   Provided the petitioner revises the proposed use pattern
as stated below, the submitted field trial data will support the
proposed tolerance for residues of halosulfuron-methyl in/on soybean
seed at 0.05 ppm.  The submitted field trial data reflect a single
postemergence foliar broadcast application at 0.0603-0.0639 lb ai/A,
with soybean seed harvested at PHIs of 88-133 days. The number and
locations of the field trials are in accordance with 860.1500 for
soybean.  An acceptable method was used for the quantitation of residues
of halosulfuron-methyl, and the study is supported by adequate storage
stability data.  No residue data were provided for soybean forage and
hay; however, feeding and grazing of soybean forage/silage and hay can
be prohibited since they are considered to be under grower control. 
Residue data for aspirated grain fractions were not provided but are not
required because application is to be made to soybean plants early in
the season.    

 

The petitioner must revise the proposed Section B/label as indicated
below and in Section 860.1200 of this review since the available residue
data do not support the proposed use: 

The proposed Section B/label must be revised to specify a maximum of one
application per year at the maximum application rate of 0.062 lb
ai/A/year since the field trial residue data reflect one application at
approximately 0.062 lb ai/A/year.                          

Although the postemergence application is restricted to the vegetative
V4 stage (4th trifoliate), prior to flowering/pod formation, a
preharvest interval for soybean seed must be stated.  Based on the
available field trial data, the proposed Section B/label must be revised
to establish a preharvest interval for soybean seed of 88 days.

The petitioner must revise the proposed Section B/label to prohibit the
grazing or feeding of treated soybean forage/silage and hay since no
residue data were provided for soybean forage and hay.

If the petitioner wishes to support a 30-day PGI/PHI for soybean
forage/silage and hay, residue data will be required for soybean forage
and hay harvested at a 30-day preharvest interval.  

860.1520 Processed Food and Feed

DER Reference:  47527401.de2.doc

The petitioner has submitted a processing study for halosulfuron-methyl
with sulfonylurea-tolerant soybeans.  In a crop field trial conducted in
IL during the 2007 growing season, a single foliar broadcast application
of a 75% WG formulation of halosulfuron-methyl was made to soybean
plants at the V3 to V4 growth stage, at 0.313 lb ai/A (5x the nominal
field rate).  Application was made using ground equipment in a spray
volume of 17 gal/A, with an NIS.  Mature soybean seed was harvested at a
106-day PHI and processed into meal, hulls, and refined oil using
procedures simulating commercial practices.

Samples of soybean seed, meal, hulls, and oil were analyzed for residues
of halosulfuron-methyl as its RRE using the available tolerance
enforcement method, Method RES-109-97-4, with modifications.  The LOQ
was 0.01 ppm in all soybean matrices.  Sample storage intervals and
conditions are reported under OPPTS 860.1380.  Adequate storage
stability data are available to support the storage intervals and
conditions for soybean seed; because processed soybean samples were
stored <30 days from collection to analysis, supporting storage
stability data are not required for these matrices.  

Residues of halosulfuron-methyl were nonquantifiable (<0.01 ppm) in/on
sulfonylurea-tolerant soybean seed harvested 106 days following a single
foliar broadcast application of the 75% WG formulation of
halosulfuron-methyl, made early postemergence (V3-V4) at 0.313 lb ai/A. 
Residues were also nonquantifiable in processed soybean meal, hulls, and
refined oil; therefore, processing factors could not be calculated.

Theoretical concentration factors, based on separation into components
(860.1520, Table 3), are 11.3x for soybean hulls, 2.2x for soybean meal,
and 12x for soybean oil.

Conclusions.  The submitted processing data for soybean are acceptable. 
The data indicate that residues of halosulfuron-methyl in soybean
processed commodities (meal, hulls, and refined oil) are unlikely to
exceed the tolerance on soybeans; therefore, separate tolerances for the
processed commodities are not needed.

  SEQ CHAPTER \h \r 1 860.1650 Submittal of Analytical Reference
Standards

Residue Chemistry Memo DP#250584, 10/28/98, G.J. Herndon (PP#6F4620 and
8F4937)

An analytical standard is currently available in the EPA National
Pesticide Standards Repository for halosulfuron-methyl (expiration
6/14/13); however, a standard is not  available for its 3-CSA
(3-chlorosulfonamide acid) metabolite (personal communication with
Dallas Wright, ACB, 2/23/09).  HED notes that a standard for the
rearrangement ester (RRE) of halosulfuron-methyl is also required in
support of the tolerance enforcement method for plant commodities. 
Analytical reference standards of the 3-CSA metabolite and the RRE must
be supplied and supplies replenished as requested by the Repository. 
The reference standards 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. Meade, MD  20755-5350

(Note that the mail will be returned if the extended zip code is not
used.)

860.1850 and 860.1900 Confined/Field Accumulation in Rotational Crops

Residue Chemistry Memo DP# 225273, 10/29/98, G.J. Herndon

Residue Chemistry Memo No DP#, 5/21/96, G.J. Herndon (Metabolism
Committee decision)

Residue Chemistry Memo DP# 192510, 8/30/93, G. Kramer

Residue Chemistry Memo DP#s 188144 and 188814, 3/11/93, G.J. Herndon
((PP#2G4073)

Acceptable confined rotational and limited field rotational 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 rotational 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.  The proposed use on soybeans is not expected to alter the
potential for inadvertent residues in rotated crops from currently
registered uses.  No additional data are required.  

860.1550 Proposed Tolerances

Halosulfuron-methyl tolerances for plant commodities have been
established in 40 CFR §180.479(a)(2) and are expressed in terms of
halosulfuron-methyl, methyl
5-[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonylaminosulfonyl-3-chloro-1-m
ethyl-1H-pyrazole-4-carboxylate.  The petitioner has proposed the
following tolerance expression: halosulfuron-methyl [methyl
3-chloro-5-(4,6-dimethoxypyrimidin-2-ylcarbamoylsulfamoyl)-1-methylpyraz
ole-4-carboxylic acid and expressed as parent equivalents.

The petitioner must submit a revised Section F to revise the proposed
tolerance expression for halosulfuron-methyl to be the same as the
Chemical Abstracts Service (CAS) nomenclature (i.e., methyl
3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfony
l]-1-methyl-1H-pyrazole-4-carboxylate) and to remove the phrase “and
expressed as parent equivalents” which is not needed for a tolerance
for the parent only.

The petitioner must submit a revised Section F to propose a tolerance
for soybean, seed instead of soybean.

Table 5 presents the proposed/recommended tolerance level and the
corrected commodity definition.

Provided the use pattern is amended as requested, adequate field trial
data are available to support the proposed tolerance of 0.05 ppm on
soybean, seed.  Because all residue values for soybean seed were below
the LOQ, the Agency’s Guidance for Setting Pesticide Tolerances Based
on Field Trial Data was not utilized for determining an appropriate
tolerance level.

The submitted soybean processing study is adequate and indicates that no
separate tolerances are required for the processed commodities of
soybean meal, hulls, and refined oil.

There are no Codex, Canadian, or Mexican MRLs established for residues
of halosulfuron-methyl in/on soybean matrices.  

Table 5. 	Tolerance Summary for Halosulfuron-methyl

Commodity	Proposed Tolerance (ppm)	Recommended Tolerance (ppm)	Comments;
Correct Commodity Definition

soybean	0.05	0.05	Soybean, seed

References

DP#s:		173627 & 180565

Subject:	PP#2G4073.  Temporary Tolerance Petition and Experimental Use
Permit for Use of MON 12000 (Permit®) on Corn; 000524-EUP-TO. 
Evaluation of Analytical Method and Residue Data. 

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		7/30/92

MRIDs:	42139400-08

DP#s:		181023

Subject:	000524-EUP-TA.  Experimental Use Permit for Use of MON 12000
and MON 13900 Together as MON 12041 (Battalion®) on Corn; Evaluation of
Analytical Method and Residue Data.  CBTS#:  10295.

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		11/12/92

MRIDs:	42396202 and 42396203

DP#s:		184435

Subject:	PP#2G4073.  Temporary Tolerance Petition and Experimental Use
Permit for Use of MON 12000 (Permit®) on Corn; 000524-EUP-TO. 
Amendment of 7/30/92 Addressing Analytical Method and Residue Data
Deficiencies.  CBTS#:  10948. 

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		1/15/93

MRIDs:	42538400-42538404

DP#s:		188144 & 188814

Subject:	  SEQ CHAPTER \h \r 1 PP#2G4073.  Temporary Tolerance Petition
and Experimental Use Permit for Use of MON 12000 (Permit®) on Corn;
000524-EUP-TO.  Amendment of 2/10/93 Addressing Analytical Method and
Proposed Label Deficiencies.  Impact of the Confined Rotational Crop
Study Results (EFGWB) on this EUP Request.   CBTS#: 11374 and 11451. 
SEQ CHAPTER \h \r 1 

From:  		  SEQ CHAPTER \h \r 1  G.J. Herndon 

To:		J. Miller/D. Kenny and   SEQ CHAPTER \h \r 1 A. Kocialski

Dated:		3/11/93

MRIDs:	None

DP#:		192510

Subject:	  SEQ CHAPTER \h \r 1 ID# 000524-UAT.  Review of limited field
rotational study of MON 12000
[3-chloro-5-[[[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]-sulfo
nyl]-1-methyl-1H-pyrazole-4-carboxylic acid, methyl ester].  Case
023936.  CBTS# 12079.

From:  		  SEQ CHAPTER \h \r 1 G. Kramer

To:		J. Miller

Dated:		8/30/93

MRIDs:	42812104

DP#s:		189198, 198051, 189189, 189178, 189183 & 189195

Subject:	PP#3F04193.  Permanent Tolerance Request for Use of MON 12000
(Halosulfuron) on Field Corn and Grain Sorghum (Milo).  Evaluation of
Analytical Method and Residue Data.

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		3/8/94

MRIDs:	42661401-07, 43042601-02

DP#:		204062

Subject:	  SEQ CHAPTER \h \r 1 PP#3F04193.   Section 3 Registration and
Permanent Tolerance Request for Use of MON 12000 (Halosulfuron) on Field
Corn and Grain Sorghum (Milo).  Submission Received 2/24/93 Addressing
Deficiencies in the Nature of the Residue in Plants and Animals.  CBTS#
13817, 13861.

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		6/22/94

MRIDs:	42678001-03

DP#:		198361

Subject:	  SEQ CHAPTER \h \r 1 PP#4G04279 and 524-EUP-74 - EUP and
Temporary Tolerance Request for the New Chemical MON 12000 on Sugarcane
and Sorghum.  CBTS No. 13092.

From:  		G. Otakie

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		7/21/94

MRIDs:	42991201-02

DP#:		202131

Subject:	  SEQ CHAPTER \h \r 1 PP#3F04193.  Section 3 Registration and
Permanent Tolerance Request for Use of MON 12000 (Halosulfuron) on Field
Corn and Grain Sorghum (Milo).  Submission Received 3/29/94 Addressing
Deficiencies in the Regulatory Enforcement Method for Animal Products
and the Proposed Section F.  CBTS# 13568

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and A. Kocialski

Dated:		10/4/94

MRIDs:	43195001 and 43177501

DP#:		214890

Subject:	  SEQ CHAPTER \h \r 1   SEQ CHAPTER \h \r 1 PP#3F04193. 
Halosulfuron (MON 12000) on Animal Commodities.  Results of the Petition
Method Validation Request.  CBTS# 15480.

From:  		G.J. Herndon

To:		J. Miller/D. Kenny and J. Smith  SEQ CHAPTER \h \r 1 

Dated:		5/3/95

MRIDs:	43195001

DP#:		None

Subject:	  SEQ CHAPTER \h \r 1 Halosulfuron (MON 12000).  The HED
Metabolism Committee Meeting Held on May 20, 1996.

From:  		G.J. Herndon

To:		  SEQ CHAPTER \h \r 1 HED Metabolism Committee

Dated:		5/21/96

MRIDs:	None

DP#:		250584

Subject:	PP#6F4620 and 8F4937.  Halosulfuron-methyl on Various
Commodities.  Results of the Petition Method Validation Request for the
Proposed Enforcement Method.

From:  		G.J. Herndon

To:		V. Walters/ J. Tompkins

Dated:		10/28/98

MRIDs:	44495801 and 44555901

DP#:		225273

Subject:	Halosulfuron.  Revised Section F Proposing Deletion of Existing
Rotational Crop Tolerances.

From:  		G.J. Herndon

To:		V. Walters/ J. Tompkins

Dated:		10/29/98

MRIDs:	None

DP#:		223801

Subject:	PP6F4661.  Section 3 Registration and Request for Permanent
Tolerances for Halosulfuron-methyl on Sweet Corn and Popcorn. 
Evaluation of Analytical Methods and Residue Data.

From:  		M. Doherty

To:		J. Tompkins/V. Walters

Dated:		11/17/98

MRIDs:	43918501

DP#:		251007

Subject:	PP8F4937.  Request for Permanent Tolerances for
Halosulfuron-methyl on Cotton, Rice, Pistachio Nuts, and Tree Nut Crop
Group (Crop Group 14 as listed in 40 CFR 180.41).  Evaluation of
Metabolism of Halosulfuron-methyl in Soybean.

From:  		M. Doherty

To:		J. Tompkins/V. Walters

Dated:		12/10/98

MRIDs:	44689501

  SEQ CHAPTER \h \r 1 Attachment:  

International Residue Limit Status sheet

Template Version September 2005

	ATTACHMENT

INTERNATIONAL RESIDUE LIMIT STATUS

Chemical Name:  methyl
5-[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonylaminosulfonyl-3-chloro-1-m
ethyl-1H-pyrazole-4-carboxylate	Common Name:

Halosulfuron-methyl

	X Proposed tolerance

( Reevaluated tolerance

( Other	Date:  02/2009

Codex Status (Maximum Residue Limits)	U. S. Tolerances

X No Codex proposal step 6 or above

( No Codex proposal step 6 or above for the crops requested	Petition
Number:  PP#8F7424

DP#:  358029

Other Identifier:  Decision # 399588  

Residue definition (step 8/CXL): N/A	Reviewer/Branch:  P. Deschamp, N.
Dodd/RAB3

	Residue definition:  halosulfuron-methyl 

Crop (s)	MRL (mg/kg)	Crop(s) 	Tolerance (ppm)

soybean	0.05

Limits for Canada	Limits for Mexico

X No Limits

( No Limits for the crops requested	( No Limits

X No Limits for the crops requested

Residue definition:  N/A

	Residue definition:  halosulfuron-methyl

Crop(s)	MRL (mg/kg)	Crop(s)	MRL (mg/kg)

	Notes/Special Instructions: S.Funk, 02/19/2009.

Page   PAGE  15  of   NUMPAGES  20 

Halosulfuron-methyl	Summary of Analytical Chemistry and Residue Data
DP#:  358029