UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MEMORANDUM 

Date: September 16, 2015 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: Sulfosulfuron. Re-evaluation of Enforcement Methods and Livestock 

Tolerances. Abbreviated Residue Chemistry Review 

PC Code: 085601 

Decision No.: 505178 

DP Barcode: D427730 

Registration No.: NA 

Petition No.: Not Applicable (NA) 

Risk Assessment Type: NA 

TXRNo.: NA 

Regulatory Action: Conditions of Review 

Case No.: 7247 

CASNo.: 141776-32-1 

MRID No.: None 40 CFR: § 180.552 

FROM: Bonnie Cropp-Kohlligian, Environmental () ..... _ \k.__ 

Risk Assessment Branch JV vir 

Health Effects Division (7509P) 

THROUGH: Dennis McNeilly, Chemist )( 

Risk Assessment Branch IV 

Effects Division -£o/\ 

P. Yvonne Barnes, Chemist ' 

Meheret Negussie, Chemist 

Chemistry Science Advisory Council (ChemSAC) 

Health Effects Division (7509P) 

TO: Kelly Ballard and Thomas Moriarty (RM 51) 

Risk Management and Implementation Branch I 

Pesticide Re-Evaluation Division (7508P) 

Executive Summary 

Sul fosulfuron (N-[[ ( 4,6-d i methoxy-2-pyrimidin yl)amino ]carbonyl]-2-( ethylsul fony l)imidazo 

[l ,2-a]pyridine-3-sulfonamide) is a selective broadleaf sulfonyl urea (SU) herbicide registered for 

foliar uses on wheat and grass. The nature of the residue in registered crops and livestock is 

adequately understood. The Health Effects Division (HED) risk assessment team has determined 

that the residues of concern for tolerance enforcement and risk assessment are sulfosulfuron and 

its metabolites which are convertible to 2-(ethylsulfonyl)-imidazo [1 ,2-a]pyridine (i.e., the ethyl 

Page 1 of 11 
Sulfosulfuron (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

sulfone chemophore). Tolerances are established under 40CFR§180.552 in/on wheat and grass 

commodities at 0.02-25 ppm, in milk at 0.02 ppm and meat commodities at 0.005-0.3 ppm. 

This memorandum was reviewed by two peer revi ewers of the Chem SAC and the following reevaluation of the enforcement methods was approved by the Analytical Methods Focus Group of 

ChemSAC which included members of the Analytical Chemistry Branch of the Biological and 

Economic Analysis Division (ACB/BEAD). 

Previously, issues were identified regarding validation of the enforcement methods. Method 

RES-082-94 (Version 2) for tolerances in/on wheat commodities and Method RES-095-96 

(Version 0) for tolerances in milk and meat commodities failed the tolerance method validation 

review and laboratory trial (TMV-RL; formerly referTed to as a petition method validation 

(PMV)) conducted by ACB/BEAD and a successful TMV of Method ES-ME-1066-01 was a 

condition of registration for the use of sulfosulfuron on grass. All three of these methods are 

common moiety methods which convert sulfosulfuron and its metabolites containing the intact 

imidazopyridine ring to the ethyl sulfone chemophore by acid hydrolysis using essentially the 

same lengthy multi-step extraction/hydrolysis procedures which differ primarily by the addition 

of an amino solid-phase extraction (SPE) cleanup step to the wheat extraction/hydrolysis 

procedure for Method RES-082-94 (Version 2). Residues are quantitated as the ethyl sulfone 

chemophore and expressed as sulfosulfuron. 

Method RES-082-94 (Version 2) and Method RES-095-96 (Version 0) use high performance 

liquid chromatography with fluorescence detection (HPLC w/tluorescence detection). While 

adequate radiovalidation and independent laboratory validation (IL V) data were provided for 

both methods, both failed the TMV-RL conducted by ACB/BEAD due to some inconsistent 

and/or low residue recoveries and concerns about the lengthy total analysis time for a sample set 

(>24 hours). After re-evaluation of the methods as written, supporting data, and the specific 

method revisions recommended in the TMV-RL which were expected to substantially improve 

residue recoveries, HED finds that: (I) for the livestock enforcement method, the original 

request to validate the method at levels <0.01 ppm may have contributed to the TMV-RL failure 

of that method and (2) achieving a limit of quantitation (LOQ) of 0.005 ppm may be beyond the 

limits of these methods given the potential for background levels in/on some matrices relati vely 

close to that level; and (3) the LOQ in/on wheat, milk and meat commodities is 0.01 ppm based 

on available method validation data taken together. Method RES-082-94 (Version 2) and 

Method RES-095-96 (Version 0), as written, are acceptable for residue determination for 

enforcement purposes, excluding tolerances in hog commodities which are no longer needed (see 

discussion below). Confirmation of residues by other means will be necessary and may be 

accomplished using the confirmatory aspects of Method ES-ME-1066-0 I discussed below (i.e., 

alternative column, mobile phase, gradient elution program and/or detection method). In the 

case of sulfosulfuron, an allowance will be made for total analysis time taking longer than 24 

hours and is discussed in greater detail below. 

Method ES-ME-1066-0 I uses liquid chromatography with tandem mass spectrometry detection 

(LC-MS/MS) and is a modified version of the HPLC w/fluorescence detection methods using a 

different column, mobile phase and gradient elution program. However, the total analysis time is 

the same as the HPLC w/tl uorescence detection methods. Method ES-ME- I 066-01 monitors 

only one mass ion transition for quantitation (m/z 2111165) of residues. Radiovalidation and 

Page 2of11 
Sulfosulfuron (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

IL V data were not provided for this method but are not required since the extraction/ hydrolysis 

procedures for Method ES-ME-1066-0 I are essentially the same as for the HPLC w/fluorescence 

detection methods. Concurrent method validation data in grass forage and hay samples fortified 

at 0.005-50.0 ppm were within or very close to generally acceptable limits (70- 120% ± 1 %), with 

one exception in/on forage at the lowest fortification level (i.e., one sample fortified at 0.005 

ppm with 64% recovery). Residues were detected inion controls; however, due to reporting 

limitations, it is not known ifresidues in controls were well below the lowest level of method 

validation (0.005 ppm). In accordance with the current Standard Operating Procedures (SOP 

Number ACB-0 19 dated 9/15/08) for a successful TMV review (TMV-R) but allowing for total 

analysis time taking longer than 24 hours (see discussion below), HED finds Method ES-MEI 066-0 l acceptable for residue determination for enforcement purposes. Due to the lack of a 

second ion transition, confirmation of residues by other means will be necessary and may be 

accomplished using the confirmatory aspects of the HPLC w/fluorescence detection methods 

discussed above (i.e., alternative column, mobile phase, gradient elution program and/or 

detection method). 

Collectively, these liquid chromatography methods are adequate for enforcement and provide for 

confirmation of residues via alternate detection methods, columns, mobile phases and/or gradient 

elution programs. The LOQ for these methods is 0.01 ppm. Although analysis time for a sample 

set using these methods will likely exceed the generally acceptable timeframe, this deviation will 

be allowed, in this case, since no acute dietary endpoint was identified for sulfosulfuron, chronic 

dietary risk estimates for sulfosulfuron are below the level of concern and most of the 

commodities with sulfosulfuron tolerances are not among the most perishable. These methods 

are available through ACB/BEAD. 

In conjunction with this re-evaluation of the enforcement methods, livestock tolerances were reevaluated and it was determined that there is no reasonable expectation of finite residues of 

concern in swine (i.e., Category 3 of 40 CFR J 80.6(a)). Therefore, HED is recommending for 

the removal of established tolerances for residues of sulfosulfuron in fat (0.005 ppm), meat 

(0.005 ppm) and meat byproducts (0.05 ppm) of hog. This recommendation is also a 

consequence of the re-evaluation of the enforcement methods (D427730) and the finding that the 

limit of quantitation for these methods is 0.01 ppm. 

Page 3 of 11 
Sul fosul furon (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

Detailed Considerations 

860.1340 Residue Analytical Methods - Enforcement Methods 

Methods RES-082-94/RES-095-96 - HPLC w/fluorescence detection 

Residue Chemistry Memos: DP#s 237683/239109, S. Chun, 9/28/98 (Wheat Petition (PP#7F4840)). 

Includes radiovalidation, ILY and livestock feeding study data. 

DP#s 239393/239394, P. Schermerhorn and L. Podhorniak (ACB/BEAD), 

1112199. Includes TMV-RL Results Methods RES-082-94/RES-095-96. 

Previously, in support of the use of sulfosulfuron on wheat (D237683/D239l09), Monsanto 

Company submitted two common moi ety methods using HPLC w/fluorescence detection for 

enforcement of tolerances in/on wheat and milk/meat commodities. These methods, Method 

RES-082-94 (Version 2) for wheat commodities and Method RES-095-96 (Version 0) for milk 

and meat commodities, convert residues of sulfosulfuron and its metabolites containing the intact 

imidazopyridine ring to the ethyl sulfone chemophore by acid hydrolysis and differ by the 

addition of an amino solid-phase extraction (SPE) cleanup step to the wheat extraction 

procedure. Residues are quantitated as the ethyl sulfone chemophore and expressed as 

sulfosulfuron. 

Adequate radiovalidation data were provided for both methods, as well as adequate independent 

laboratory validation (ILV) data in wheat grain at 0.01 and 0.05 ppm, wheat forage at 4.0 and 20 

ppm, milk at 0.004 and 0.008 ppm and beef liver at 0.004 and 0.10 ppm (D237683/D239109). 

HED requested a TMV-RL (formerly referred to as a PMV) of the wheat method by the 

ACB/BEAD in wheat grain at 0.01 and 0.02 ppm and in wheat forage at 0.01 , l .5 and 3.0 ppm. 

Given the concurrent recommended tolerance levels in milk (0.006 ppm) and meat commodities 

(0.005-0.05 ppm), HED requested a TMV-RL of the milk/meat commodity method by the 

A CB/BEAD in milk at 0.003 and 0.004 ppm, beef liver at 0.005, 0.05 and 0.10 ppm and beef 

muscle at 0.005 and 0.0 I ppm. The A CB/BEAD conducted the TMV-RL using substitutions for 

the method prescribed column, mobile phase and gradient elution program to substantially 

reduce HPLC analysis time (method run time was reduced from 53 to 15 minutes). The methods 

failed the TMV-RL (D239393/D239394) due mainly to some inconsistent and/or low residue 

recoveries from the multi-step extraction/hydrolysis procedures and concerns about the lengthy 

extraction/hydrolysis/analysis time for a sample set (>24 hours even with the ACB/BEAD time 

saving substitutions/recommendations). However, for the milk/meat commodity enforcement 

method, HED examined the TMV-RL and notes the following with regards to the attempt to 

validate the method at levels <0.01 ppm in livestock commodities which may have contributed to 

the TMV-RL failure related to residue recoveries: 

• The lowest calibration level in the method, as written, was 0.0112 ppm, as sulfosulfuron, 

and above the lowest level of attempted method validation. 

• Example beef and liver chromatograms from the TMV-RL indicate residues in control 

samples close to the lowest level of method validation (ca. 0.005 ppm). Detectable 

residues in control samples of milk/cream and tissues were also noted in the cattle 

feeding study (0237683/D239109). Enforcement methods cannot employ untreated 

control samples to correct residues in treated samples. 

Page 4 of 11 
Sulfosulfuron (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

HED also notes that since the livestock method TMV-RL was conducted, livestock tolerances 

have increased significantly, excluding tolerances in hog commodities which are no longer 

needed (see 860.1480 Meat, Milk, Poult!y, and Eggs below), and validation of the method at 

<0.0 I ppm is no longer necessary. 

The extraction/hydrolysis procedures of these methods are briefly described below along with 

the specific revisions to these procedures that ACS/BEAD recommended to improve residue 

recoveries or analysis time (0239393/0239394) and any HED re-evaluation of the issues. 

Excluded from this discussion are revisions/observations that ACB/BEAD provided regarding 

laboratory technique (i.e., how to deal effectively with the formation of emulsions and the 

interpretation of typical procedural instructions such as gentle shaking, etc.) given the level of 

expertise expected for enforcement personnel. 

l. Homogenized samples are extracted with 100 mL acetonitrile (ACN):water (I: I, v:v), 

filtered and concentrated. For dry crop samples such as straw and hay, an additional 50 

mL of extraction solvent may be added. The method cautions that concentration of the 

initial ACN fraction is a critical step and must be done slowly so that residues are not 

lost. 

2. The extract is refluxed with HCl overnight to hydrolyze sulfosulfuron to the ethyl sulfone 

chemophore. Alternatively, the san1ple can be hydrolyzed by heating in a microwave 

oven for 1 hour at 40 psi to save analysis time. ACB/BEAD selected the overnight 

hydrolysis option but noted that, regardless of the option selected, the subsequent lengthy 

extraction procedures would still take another working day and the overnight hydrolysis 

provided a good stopping point in the procedure. HED finds that this time saving 

measure plus others suggested by ACB/BEAD would not reduce the total analysis time to 

<24 hours. 

3. The hydrolyzed extract is adjusted to at least pH 9 with NaOH. The method cautions that 

if the sample is neutral or slightly acidic, insufficient cleanup will be observed. 

4. The basic solution is partitioned with methylene chloride (MeCh) using a separatory 

funnel. The method prescribes gentle shaking of the separatory funnel and cautions that 

an emulsion may form if samples are shaken too vigorously. 

5. The MeCb is evaporated to dryness by rotary evaporation. The residue is re-dissolved in 

MeC'2 and diluted with isooctane. 

6. The solution is cleaned up through a Florisil SPE column, and residues are eluted with 

2% methanol (MeOH):MeCh. The solvent is removed by evaporation to dryness by 

rotary evaporation. ACB/BEAD recommended special care during the evaporation 

procedure; however, this recommendation was only identified as a relatively small 

improvement (I 0-20%) in the residue recoveries in milk samples which were fortified at 

very low levels (:S0.004 ppm). Moreover, the method already includes a reasonable 

precaution that concentration/evaporation steps can be critical in the procedure and must 

be done slowly so that residues are not lost. HED finds that the precautions in the 

methods, as-written, adequately address the ACB/BEAD recommendation. 

7. For wheat only, residues are re-dissolved in MeCh:isooctane and cleaned up through an 

Amino SPE column, and residues are eluted with 40% ethyl acetate in iso-octane. The 

solvent is removed by evaporation to dryness. ACB/BEAD recommended that this step 

be eliminated to shorten analysis time. However, HED finds that this time saving 

measure plus others suggested by ACB/BEAD would not reduce the total analysis time to 

<24 hours. 

Page 5 of 11 
Sulfosulfuron (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

8. Residues are re-dissolved in ACN:water (10:90, v:v) for analysis. ACS/BEAD 

recommended that ACN should be added first to dissolve the residues before the water 

and noted that liver samples became cloudy with the addition of the water, requiring 

filtration. ACB/BEAD found that this procedure significantly increased residue 

recoveries in liver samples. However, HED notes that the method already includes a 

reasonable precaution that it may be difficult to re-dissolve samples after evaporation and 

that a small amount of ACN is recommended. HED finds that the precautions in the 

methods, as-written, adequately address the ACB recommendation. 

As a consequence of the failed TMV-RL, Monsanto Company was advised to revise both 

methods in accordance with the ACB/BEAD recommendations provided in the TMV-RL and resubmit the revised methods. In the meantime, the ACB/BEAD developed a revised extraction 

procedure and agreed to provide instructions to any state lab requesting the method. However, 

HED has re-evaluated the methods, available data and the TMY-RL and finds that: (1) the 

methods, as written, adequately address most of the ACB recommendations regarding the 

extraction procedures; (2) total analysis time will likely exceed 24 hours, even with the time 

saving measures suggested by ACB!BEAD; and (3) achieving a LOQ of 0.005 ppm may be 

beyond the limits of the methods for some matrices. 

Method ES-ME-1066-01 - LC-MS!MS 

Residue Chemistry Memos: DP# 328450, S. Levy, 07/25/07 (Grass Petition (PP#6F7031)). 

DP# 332807, S. Levy, 10/17/06 (TMV Request Method ES-ME-1066-0 1). 

MRID: 4675380 I (Method ES-ME-I 066-0 I description and fortification recovery data) 

Previously, in support of the use of sulfosulfuron on grass (0 328450), Monsanto Company 

submitted Method ES-ME-I 066-01 (MRID 4675380 I, pages 166-186), a modified version of 

Method RES-082-94 (discussed above). Method ES-ME-1066-01 , is a conunon moiety method 

using LC-MS/MS. Radiovalidation and lLV data were not provided for this method but are not 

required since the extraction/hydrolysis procedures for Method ES-ME-1 066-01 are essentiall y 

the same as for the HPLC w/fluorescence detection methods. It was submitted to the 

ACB/BEAD for a TMV (D332807) just before the standard operating procedure (SOP) for 

reviewing tolerance methods was issued (SOP Number ACB-0 19 dated 9/15/08). A successful 

TMV for Method ES-ME-I 066-01 was identified as a condition of registration for sulfosulf uron 

on grass (0328450). Since, there is no record that ACB!BEAD conducted this TMV, HED has 

conducted a TMV review (TMV-R) in accordance with the current SOP. 

Method ES-ME-I 066-0 l employs essentially the same extraction/hydrolysis procedures as the 

HPLC w/fluorescence detection methods discussed in detail above with the following significant 

improvements: (1) there is no amino solid-phase extraction (SPE) cleanup step which should 

save analysis time and (2) the volume of the initial extraction solvent (i.e., ACN:water (1: I, v:v)) 

is increased from 100 to 150 mL which may contribute to adequate residue recoveries. It also 

uses a different column, mobile phase and gradient elution program than the HPLC 

w/ tluorescence detection methods; however, the total analysis time is likely to be the same. 

Residues were quantitated as the ethyl sulfone chemophore and expressed as sulfosulfuron. The 

method monitors only one mass ion transition for quantitation, m/z 2 1 I / 165. 

Concurrent method validation data in grass forage and hay samples fortified at 0.005-50.0 ppm 

Page 6 of 11 
Sulfosul furon (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

were within or very close to generally acceptable limits (70-120% ± 1%), with one exception 

inion forage at the lowest fortification level (i.e., one sample fortified at 0.005 ppm with 64% 

recovery). See Table l . Residues were detected in controls (based on area counts reported for 

controls, fortified samples and calibration standards); however, it is not known if residues in 

controls were well below the lowest level of method validation (0.005 ppm) since they were not 

quantified (i.e., reported at 0.00 ppm). 

Table 1. Summary of Concurrent Recoveries of Sulfosulfuron Residues from Grass Forage a nd Hay. 

Matrix Fortification Level Sample size Uncorrected Recoveries 

(ppm) (%) 

0.005 5 64,93.93.97, JOO 

0.010 4 106. 90. 81. 81 

0.020 4 90, 90,93.93 

0.050 3 69. 77. 99 

0. 100 3 11 2. 90, 97 

Grass. forage 

0.200 4 105. 107. 111. 103 

0.500 4 113, 82, 100. 99 

1.000 5 109. 92.98. 99.96 

2.000 6 113. 107.93.96. 101.90 

5.000 5 JOO. 98. 115. 108. 107 

10.000 7 103. 112. 105.94.89 

20.000 2 99, 104 

0.005 2 85.81 

0.010 2 88, 83 

0.020 3 83.88. 85 

0.050 3 93.96. 110 

0. 100 3 86. 91, 82 

0.200 I 94 

Grass. hay 0.500 I 109 

1.000 I 11 0 

2.000 2 109. 107 

5.000 1 113 

10.000 I 96 

20.000 I 99 

50.000 2 106. 110 

Conclusions. Method RES-082-94 (Version 2) and Method RES-095-96 (Version 0 ) fai led the 

TMV-RL conducted by ACB/BEAD. After re-evaluation of Method RES-082-94 (Version 2) 

and Method RES-095-96 (Version 0) as written, supporting data, and the specific method 

revisions recommended in the TMV-RL which were expected to substantially improve residue 

recoveries, HED fi nds that: (1) for the livestock enforcement method, the original request to 

validate the method at levels <0.01 ppm may have contributed to the TMV-RL failure of that 

method and (2) achieving a limit of quantitation (LOQ) of 0.005 ppm may be beyond the limits 

of these methods given the potential for background levels in/on some matrices relatively close 

to that level; and (3) the LOQ in/on wheat, milk and meat commodities is 0.01 ppm based on 

available method validation data taken together. Method RES-082-94 (Version 2) and Method 

RES-095-96 (Version 0), as written, are acceptable for residue determination for enforcement 

purposes, excluding tolerances in hog commodities which are no longer needed (see discussion 

under 860. 1480). Confirmation of residues by other means will be necessary and may be 

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Sul fosul furon (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

accomplished using the confirmatory aspects of Method ES-ME-I 066-01 discussed below (i.e., 

alternative column, mobile phase, gradient elution program and/or detection method). In the 

case of sulfosul furon, an allowance will be made for total analysis time taking longer than 24 

hours and is discussed in greater detail below. 

A successful TMV of Method ES-ME-1066-01 was a condition of registration for the use of 

sulfosulfuron on grass. Method ES-ME-1066-01 uses liquid chromatography with tandem mass 

spectrometry detection (LC-MS/MS) and is a modified version of the HPLC w/fluorescence 

detection methods using a different column, mobile phase and gradient elution program. 

However, the total analysis time is the same as the HPLC w/fluorescence detection methods. 

Method ES-ME-1066-01 monitors only one mass ion transition for quantitation (rn/z 2 11 / 165) of 

residues. Radiovalidation and lL V data were not provided for this method but are not required 

since the extraction/hydrolysis procedures for Method ES-ME-1066-01 are essentially the same 

as for the HPLC w/fluorescence detection methods. Concurrent method validation data in grass 

forage and hay samples fortified at 0.005-50.0 ppm were within or very close to generally 

acceptable limits (70-120% ± 1 %), with one exception in/on forage at the lowest fortification 

level (i.e., one sample fortified at 0.005 ppm with 64% recovery). Residues were detected in/on 

controls; however, due to reporting limitations, it is not known if residues in control were well 

below the lowest level of method validation (0.005 ppm). In accordance with the current 

Standard Operating Procedures (SOP Number ACB-019 dated 9115/08) for a successful TMV 

review (TMV-R) but allowing for total analysis time taking longer than 24 hours (see discussion 

below), HED finds Method ES-ME-1066-01 acceptable for residue determination for 

enforcement purposes. Due to the lack of a second ion transition, confirmation of residues by 

other means will be necessary and may be accomplished using the confirmatory aspects of the 

HPLC w/fluorescence detection methods discussed above (i.e., alternative column, mobile phase, 

gradient elution program and/or detection method). 

Collectively, these liquid chromatography methods are adequate for enforcement and provide for 

confirmation of residues via alternate detection methods, columns, mobile phases and/or gradient 

elution programs. The LOQ for these methods is 0.0 I ppm. Although analysis time for a sample 

set using these methods will likely exceed the generall y acceptable timeframe, this deviation will 

be allowed, in this case, since no acute dietary endpoint was identified for sulfosulfuron, chronic 

dietary risk estimates for sulfosulfuron are below the level of concern and most of the 

commodities with sulfosulfuron tolerances are not among the most perishable. These methods 

are available through the ACB!BEAD. 

860.1360 Multircsidue Methods 

Residue Chemistry Memos: DP#s 237683/239 109. S. Chun. 9/28/98 (Wheat Petition (PP#7F4840)) 

DP# 239417, S. Chun, 9/30/97 

In support of the petition for use on wheat, acceptable data were submitted reflecting testing 

through the U.S. Food and Drug Administration (FDA) Multiresidue Methods for sulfosulfuron 

and its sulfonamide metabolite. Sulfosulfuron and its metabolite were not recovered using 

Protocol A: Sulfosulfuron appeared to degrade under the conditions used in Protocol C. Based 

on the results of Protocol C testing, sulfosulfuron and its metabolite were not tested through 

Protocols D, E, or F. The results of the multi residue methods testing were forwarded to FDA. 

Page 8 of 11 
Sul fosul furon (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

860.1480 Meat, Milk, Poultry, and Eggs 

Residue Chemistry Memos: DP#s 237683/239109, S. Chun, 9/28/98 (Wheat Petition (PP#7F4840)) 

Includes ruminant feeding study data. 

DP# 328450, S. Levy, 7/25/07 (currently established livestock tolerances 

determined) 

The currently established livestock commodity tolerances reflect dietary burdens for 

sulfosulfuron to beef cattle (33.6 1 ppm), dairy cattle (22.41 ppm), poultry (0.016 ppm) and swine 

(0.016 ppm) calculated (0 328450) before the most recent guidance on constructing maximum 

reasonably balanced diets (MRBDs; Guideline 860.1000 Table I Feedstuffs (June 2008)) was 

available. In accordance with Guideline 860.1000 Table I Feedstuffs (June 2008), the updated 

MRBDs for dairy cattle (21 ppm), poultry (0.0 15 ppm) and swine (0.0 10 ppm) are little changed 

from the prior dietary burdens; however, the MRBD for beef cattle ( 1.2 ppm) is much lower 

because grass forage is no longer considered a feedstuff for beef cattle. The calculated MRBDs 

are presented below in Table 2. 

Table 2. Calculation of Dieta ry Burdens of Sulfosulfuron to Livestock. 

Feedstuff Type' %Dry % Diet2 Residue Estimates3 

Mauer2 (ppm) 

Beef Cattle (15% R; 80%CC; 5%PC) 

Grass, hay R 88 15 7.14 

Wheat, grain cc 89 20 0.02 

Wheat, milled byproducts cc 88 40 0.02 

Untreated cc -- 20 -- Untreated PC -- 5 -- TOT AL BURDEN -- -- 100 -- Dairy Cattle (45% R; 45%CC; 10% PC) 

Grass, forage R 25 45 11.65 

Wheat, grain cc 89 20 0.02 

Wheat, milled byproducts cc 88 25 0.02 

Untreated PC -- 10 -- TOT AL BURDEN -- -- 100 -- Poultry (75%CC; 25% PC) 

Wheat, grain cc 89 75 0.02 

Untreated PC -- 25 -- TOT AL BURDEN -- -- 100 -- Swine (85%CC; 15% PC) 

Wheat, milled byproducts cc 88 50 0.02 

Untreated cc -- 25 -- Untreated PC -- 15 -- TOT AL BURDEN -- -- 100 -- I R: Roughage; CC: Carbohydrate concentrate; PC: Protein concentrate. 

2 Guideline 860.1000 Table I Feedstuffs (June 2008). 

3 Wheat grain and milled byproducts estimate based on tolerance level inion grain. 

Grass hay and forage based on highest average field trial (HAFT). 

4 Contribution = ([tolerance/% OM] X % diet) for beef and dairy cattle. 

Contribution = ((tolerance] X % diet) for poultry and swine. 

Page 9of11 

Dietary Contribution4 

(ppm) 

1.2 

0.005 

0.009 

0.0 

0.0 

1.2 

21.0 

0.005 

0.006 

0.0 

21 

0.015 

0.0 

0.015 

0.010 

0.0 

0.0 

0.0 10 
Sulfosulfuron (08560 I) Abbreviated Residue Chemistry Review DP#: 427730 

An acceptable ruminant feeding study is available (0 237683/0 239109). Dairy cattle were dosed 

for 28 consecutive days with sulfosulfuron at dose levels of 8. 1, 23.5 and 8 1.7 ppm in the diet. 

These dose levels are approximately 0.39x, 1.1 x and 3.9x the recalculated MRBD for beef/dairy 

cattle (I. I pprn/2 1 ppm) and 81 Ox, 2,350x and 8, l 70x the recalculated MRBD for swine (0.010 

ppm). Residues appeared to plateau in milk by Day 4, and data for all matrices were 

approximately linear with the dosing levels. The maximum residues of sulfosulfuron found in 

milk and cow tissues are listed in Table 3 below. 

Table 3. Maximum Sulfosulfuron Residues by Feeding Level from the Ruminant Feeding Study. 

Matrix Maximum Residues (ppm) 

Dose 8. 1 ppm Dose 23.5 ppm Dose 8 1.7 ppm 

0.39x Cattle Diet1 I. Ix Cattle Diet' 3.9x Cattle Diet 1 

8 1 Ox Swine Diet

2 2,350x Swine Diet2 8, I 70x Swine Diet

2 

Milk 0.004 0.019 0.034 

Skim milk 0.009 0.024 

Cream 0.005 0.006 0.0 12 

Fat $0.005 0.007 0.070 

Muscle $0.005 0.006 0.024 

Kidney 0. 115 0.223 1.006 

Liver 0.095 0.276 0.556 

1 Based on MRBD for dairy cattle (21 ppm). which is substantially higher than the MRBD for beef cattle (1.2 ppm). 2 Based on MRDB for swine (0.010 ppm). 

A poultry feeding study has not been submitted. HED previously concluded that, due to the low 

residue levels in the hen metabolism study and low residue levels found in wheat grain, a poultry 

feeding study was not necessary, and tolerances for residues in poultry commodities were not 

required (D237683/D239 I 09). 

Co11c/11sio11s. Based on the results of the available feeding study, the established tolerances for 

residues of sulfosulfuron in milk (0.02 ppm) and in fat (0.02 ppm), meat (0.01 ppm) and meat 

byproducts (0.3 ppm) of cattle, goat, horse and sheep are appropriate; however, given the very 

low dietary burden for swine (0.0 10 ppm), the established tolerances for residues of 

sulfosulfuron in the fat (0.005 ppm), meat (0.005 ppm) and meat byproducts (0.05 ppm) of hog 

are not needed and should be removed since there is no reasonable expectation of residues in 

swine commodities (i.e., Category 3 of 40 CFR l 80.6(a)). Furthermore, there is no reasonable 

expectation of finite residues of sulfosulfuron in poultry given the very low dietary burden for 

poultry (0.0 15 ppm) (i.e., Category 3 of 40 CFR l 80.6(a)). 

Page 10of 11 
Sulfosulfuron (085601) Abbreviated Residue Chemistry Review DP#: 427730 

References 

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239417 

PP# 7F04840. Multiresidue Method Testing of MON 37500 and Sulfonamide 

Metabolite (CP 147937). 

S. Chun 

F.D. Griffith 

30-SEP-1997 

44295713 

237683 and 239109 

PP# 7F04840. New Chemical - Sulfosulfuron (i.e. MON37500, MaverickTM) 

in/on Wheat. Evaluation of Residue Data and Analytical Methods. Chemical No. 

08560 I. Case No. 288878. 

S. Chw1 

J. TompkinsN. Walters 

28-SEP-1998 

44295702-04, 44295707-ll, 44295713-14, 44295716-18, 44295735, 44309301 

232393 and 232394 

PP# 7F04840. Sulfosulfuron (MON37500) on Wheat and Animal RACs. 

Request for Petition Method Validation: I) Wheat RA Cs MR10#442957- l 0 and 

2) Animal Commodities MRID#442957-l I . ACB #898-(2,3). 

P. Schermerhorn and L. Podhomiak 

E. Zager and D. Stubbs 

12-JAN-1999 

442957 10-11 

332807 

Sulfosulfuron. Registration Request for Crop Group 17 (Grass Forage, Fodder, 

and Hay). Request for Petition Method Validation (PMV). 

S. Levy 

F. Siegelman 

17-0CT-2006 

46753801 

328450 

Sulfosulfuron. New Uses on Grass Forage, Fodder, and Hay (Crop Group 17). 

S. Levy 

J. Tompkins 

25-JUL-2007 

46753801 

Page 11 of 11