### 2 

# R EGISTRATION 

# R EVIEW



# E COLOGICAL 

# R ISK 

# A SSESSMENT 

# P ROBLEM 

# F ORMULATION FOR 

# :



# Sulfosulfuron

P REPARED 

### B Y 

### :

Ron Parker, Senior Environmental Engineer Amy Blankinship, Chemist Environmental Risk Branch 3 Environmental Fate and Effects Division Office of Pesticide Programs

R EVIEWED 

### B Y 

### : Melissa Panger, Senior Effects Scientist James Hetrick, Senior Advisor Environmental Risk Branch 3 Environmental Fate and Effects Division Office of Pesticide Programs

### 3 

## T ABLE OF 

## C ONTENTS



### T ABLE OF 

### C ONTENTS



### ................................ ................................ ................................ ..................... 3 1.0 Description of Regulatory Action

................................ ................................ .............. 6 2.0 Stressor Source and Distribution

................................ ................................ .............. 6 2.1 Mechanism of Action

................................ ................................ ................................ ........ 6 2.2 Overview of Pesticide Usage

................................ ................................ ............................ 7 3.0 Fate of Sulfosulfuron in the Environment

................................ ............................. 10 3.1 Metabolites and/or Degradates

................................ ................................ ...................... 14 4.0 Conclusions from Previous Assessments

................................ ............................ 16 5.0 Ecological Effects

................................ ................................ ................................ ........ 17 5.1 Terrestrial Organism Toxicity Data

................................ ................................ .............. 18 5.1.1 Avian Toxicity, Acute

................................ ................................ ............................... 19 5.1. 2 Avian Toxicity, Chronic

................................ ................................ ........................... 19 5.1.3 Mammal Toxicity, Acute

................................ ................................ .......................... 20 5.1.4 Mammal Toxicity, Chronic

................................ ................................ ....................... 20 5. 1.5 Terrestrial Invertebrate Toxicity, Acute

................................ ................................ ... 21 5.1.6 Terrestrial Plant Toxicity

................................ ................................ .......................... 21 5.2 Aquatic Organism Toxicity Data

................................ ................................ ................... 22 5.2.1 Fish Toxicity Data, Acute

................................ ................................ ......................... 24 5.2.2 Fish Toxicity Data, Chronic

................................ ................................ ...................... 24 5.2.3 Aquatic Invertebrate Toxicity Data, Acute

................................ ............................... 25 5.2.4 Aquatic Invertebrate Toxicity Data, Chronic

................................ ............................ 25 5.2.5 Aquatic Plant Toxicity Data

................................ ................................ ...................... 26 6.0 Evaluation of Non

- definitive Toxicity Values

................................ ....................... 27 7.0 Uncertainties Associated with Lack of Data or Acceptable Studies

.............. 29 7.1 Parent Sulfosulfuron

................................ ................................ ................................ ....... 29 7.2 Degradate/Metabolites of Sulfosulfuron

................................ ................................ ....... 31 8.0 Incident Database Review

................................ ................................ ......................... 34 9.0 Monitoring Data

................................ ................................ ................................ ............ 34 10.0 Clean W ater Act

................................ ................................ ................................ ............ 35 11.0 Ecosystems Potentially at Risk

................................ ................................ ................ 36 12.0 Assessment Endpoints

................................ ................................ .............................. 36 13.0 Conceptual Model

................................ ................................ ................................ ........ 37 14.0 Risk Hypothesis

................................ ................................ ................................ ........... 41 15.0 Analysis Plan

................................ ................................ ................................ ................. 43 15.1 Ecological Measures of Exposure

................................ ................................ .................. 43 15.2 Drinking Water Measures of Exposure

................................ ................................ ........ 44 15.3 Measures of Effect

................................ ................................ ................................ ........... 44 15.4 Uncertainties in the Analysis Plan

................................ ................................ ................. 45 15.5 Endangered Species Assessments

................................ ................................ .................. 45 16.0 Anticipated Data Needs

................................ ................................ .............................. 46 16.1 Environmental Fate

................................ ................................ ................................ ........ 48 16.2 Ecological Effects

................................ ................................ ................................ ............ 48 17.0 Other Information Needs

................................ ................................ ............................ 49 18.0 Data Call

- In Tables For Fate and Ecological Effect Studies

............................. 50

### 4

18.1 Environmental Fate Studies

................................ ................................ ........................... 50 18.2 Ecological Effects Studies

................................ ................................ ............................... 52 19.0 References

................................ ................................ ................................ ..................... 58

Tables

Table 1. Current Registrations of Sulfosulfuron

................................ ................................ ...... 7 Table 2. Current Application Data for Sulfosulfuron

................................ .............................. 8 Table 3. Summary of Uncertainties for Registered Label for Sulfosulfuron

......................... 8 Table 4. Screening Level Usage Estimates (SLUA) for Agricultural Uses of Sulfosulfuron as of December 1, 2010.

................................ ................................ .......... 10 Table 5. Physical/Chemical Properties for Sulfosulfuron (Source: EPA Product Chemistry Review)

................................ ................................ ................................ ............................. 12 Table 6. General Env ironmental Fate Property Values for Sulfosulfuron

........................... 13 Table 7. Degradation/Metabolite Products Observed in Various Studies

............................ 14 Table 8. Most Sensitive Terrestrial Organism Toxicity Values for Sulfosulfuron Based on Available Data

................................ ................................ ................................ ................. 18 Table 9. Most Sensitive Aquatic Organism Toxicity Values for Sulfosulfuron Based on Available Data

................................ ................................ ................................ ................. 23 Table 10. Detection Frequency and Maximum Concentration of Sulfosulfuron at Four Drinking Water Facilities

................................ ................................ ............................... 35 Table 11. Available Ecological Effects Data for Terrestrial Animals Exposed to Sulfosulfuron and Remaining Data Gaps.

................................ ................................ .... 46 Table 12. Available Ecological Effects Data for Aquatic Animals Exposed to Sulfosulfuron and Remaining Data Gaps.

................................ ................................ ............................ 46 Table 13. Available Ecological Effects Data for Plants Exposed to Sulfosulfuron and Remaining Data Gaps.

................................ ................................ ................................ .... 47 Table 14. Degradates and Requested Studies

................................ ................................ .......... 48

Figures Figure 1. 2002 Estimated Annual Agricultural Use Map for Sulfosulfuron (Sou rce: USGS) 9 Figure 2. Sulfosulfuron Chemical Structure

................................ ................................ ........... 11 Figure 3. Conceptual Model Depicting Potential Risks to Terrestrial Animals and Plants from the Use of Sulfosulfuron

................................ ................................ ........................ 38 Figure 4. Conceptual Model Depicting Potential Risks to Aquatic Animals and Plants from the Use of Sulfosulfuron

................................ ................................ ................................ . 39 Figure 5. Conceptual Model Depicting Potential Risks to Terrestrial Vertebrates and Invertebrates from Inhalation and Drinking Water Exposure from the Use of Su lfosulfuron

................................ ................................ ................................ ................... 40

Appendicies Appendix A. MRID Bibliography

................................ ................................ ............................ 60 Appendix B. Summary of Structure, Chemical Formulas and Common Names

................ 74 Appendix C. Summary of Toxicity Studies for Sulfosulfuron

................................ ............... 76 Appendix C. Summary of Toxicity Studies for Sulfosulfuron

................................ ............... 76 Appendix D. GENEEC2 Output

................................ ................................ ............................... 83

### 5

Appendix E. T

- REX Output

................................ ................................ ................................ ..... 84 Appendix F. SIP Output

................................ ................................ ................................ ............. 87 Appendix G. STIR Input and Output

................................ ................................ ...................... 88

### 6



## 1.0 Description o f Regulatory Action

The Food Quality Protection Act of 1996 mandated the EPA to implement a new program for assessing the risks of pesticides 1



### . All pesticides distributed or sold in the United States generally must be registered by EPA. The decision to register a pesticide is based on the consideration of scientific data and other factors showing that it will not cause unreasonable risks to human health, workers, or the environment when used as directed on product labeling. The registration review program is intended to ensure that, as the ability to assess risk evolves and as policies and practices change, all registered pesticides continue to m eet the statutory standard of no unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the new registration review program, the Agency periodically r eevaluates pesticides to ensure t hat as change occurs, products in the marketplace can be used safely.

As part of the implementation of the new Registration Review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its evaluation to determine whether sulfosulfuron uses continue to meet the FIFRA standard for registration. This problem formulation for the environmental fate and ecological risk assessment chapter in support of the reg istration review is intended for the initial docket opening, which starts the public phase of the review process. This problem formulation considers all current and active registrations for sulfosulfuron

. The MRID bibliography for sulfosulfuron is presen ted in Appendix A.

The purpose of problem formulation is to provide the foundation for the environmental fate and ecological risk assessment being conducted for sulfosulfuron. It sets the objectives for the risk assessment, evaluates the nature of the p roblem, and provides a plan for analyzing the data and characterizing the risk (US EPA, 1998).



## 2.0 Stressor Source and Distribution

Sulfosulfuron (PC code 085601) is used for pre and postemergence control of many annual and perennial grasses and broadleaf weeds, such as brome and mustard species. It is registered for use on wheat, pastures (including Bermuda grass and Bahia grass), rangeland and a wide variety of non

- crop uses including golf courses, fallow land and rights

- of

- ways.



## 2.1 Mechanism of Action

Su lfosulfuron [N

- [[4,6

- dimethoxy

- 2

- pyimidinyl)carbonyl]

- 2

- )ethylsulfonyl)

- imidazo[l,2

- a]pyridine

- 3

- sulfonamide ] is a sulfonylurea class herbicide that inhibits acetolactate synthase (ALS)

. ALS is necessary for the synthesis of amino acids in plants.

1 ( http://www.epa.gov/oppsrrd1/registration_review/ )

### 7



## 2.2 Over view of Pesticide Usage

Sulfosulfuron is formulated either as a water dispersible or soluble granule formulation (WDG or WSG) or a soluble concentrate (SC).

According to the labels, sulfosulfuron may be applied with aerial or ground equipment to wheat, non

- crop, pasture and rangeland , sod farms, golf courses, landscaped areas, native grass sites, and ornamental nurseries . The type of applications include: broadcast, hand

- held and high volume. The type of equipment that may be used includes: ground, airc raft, helicopter, hand

- held spray guns, and backpack sprayers.

Current registrations and uses of sulfosulfuron are shown in Table 1 and Table 2 below.

Table 1 . Current Registrations of Sulfosulfuron

Product Name (Registrant) EPA Registration Number (latest label date) 1 Active Ingredients (% w/w) Crops

Section 3 End Use Products and Technical Chemical Mon 37500 Technical ( Monsanto Company ) Technical Chemical 524

- 499 ( 10/12/10 ) Sulfosulfuron 98. 0 % Not Applicable

Maverick/Outrider Herbicide ( Monsanto Company ) Water Dispersible Granule 524

- 500 ( 09/22/10 ) Sulfosulfuron 75.0 % Non

- crop sites 2 ; Pasture and Rangeland 3 ; and Wheat (winter and spring)

Maverick Pro (C/A) ( Monsanto Company ) Water Soluble Granule 524

- 525 (0 5/25/00 ) (09/02/01 Supplemental label) Sulfosulfuron 75.0 % Wheat (winter)

Mon 37525 NC/ Mon 37525 W ( Monsanto Company ) Soluble Concentrate 524

- 526 ( 03/15/01) Sulfosulfuron 24.1 % Non

- crop sites 2 ; Wheat (winter and spring)

Mon 44940 SC (Monsanto Company) Soluble Concentrate 524

- 533 (02/27/02) Sulfosulfuron 24.1% Sod farms and Golf Courses

Certainty Turf Herbicide (Monsanto Company) Water Dispersible Granule 524

- 534 (12/04/06) (01/25/10 Supplemental label) Sulfosulfuron 75.0% Landscaped areas; Ornamental Nurseries; Sod farms and Highly managed turf and Native grass sites 4

1 Date of label according to Office of Pesticide Program Information Network (OPPIN)
2 Non

- crop sites include: airports, conservation areas (non

- crop tree sites) (on 524

- 500 only), ditch banks, dry ditches, dry canals, fallow areas, fencerows, industrial sites, lumberyar ds, manufacturing sites, natural areas (on 524

- 500 only), petroleum tank farms and pumping installations, railroads, roadsides, storage areas, utility rights

- of

- way, utility sites (on 524

- 500 only) and substations, warehouse areas; wildlife areas (non

- crop tree sites) (on 524

- 500 only), and similar industrial and noncrop sites (on 524

- 526 only).
3 Pasture and Rangeland sites include: bermudagrass and bahiagrass pasture sites, pasture and rangeland sites in states west of Mississippi River, native grasses a nd conservation reserve program sites, and forestry conifer release
program. 4 Sod farms, highly managed turf and native grass sites include: apartment complexes, athletic fields, cemeteries, golf courses (except putting greens), hotel properties, office complexes, parks, public turf areas, retail sites, storage facilities, school grounds, sod and turfgrass seed farms and other highly managed turfgrass sites.

### 8

Table 2 . Current Application Data for Sulfosulfuron Crop Max Single

Appl ication
rate lbs a.i./A Number of

Applications Max

Application
per year/season lb a.i./A Application

Method Application

Interval (days) Reg #*

Non

- crop sites 0.0938 N.S. 0.125 Ground; Aerial 21 to N.S 524

- 500; 524

- 526 Pasture and Rangeland 0.0938 1 to N.S 0.125 Ground; Aerial 21 to N.S 524

- 500; 524

- 534 Sod farms and Turf

areas 0.0938 1 to N.S. 0.125 Ground 14 to N.S. 524

- 533; 524

- 534 Landscaped areas and Ornamental Nurseries 0.0586 1 0.117 Directed Spray; Over

the

- top; Pre

plant 4 wks 524

- 534 ( Supple

mental label )

Wheat (winter and spring) 0.0313 1 or 2 (524

- 500 only) 0.0313

(0.0352) 1 / cropping

season Ground;

Aerial Not

applicable for single app; 14 days for split app. (524

- 500 only) 524

- 500;

524

- 525; 524

- 526

N

. S

. =not specified on label *: While every crop listed in the “Crop” column may not be a registered use for every EPA Reg #’s listed at least one crop is for every reg #. Application rates represent maximum application rate for a least one of the EPA Reg# listed. Other labels may have slightly different application rates.
1 Max rate of 0.0352 lb a.i./A for split applications for label 524

- 500 only where single max app is 0.0176 lb a.i./A



### There are some uncertainties in the registered labels such as re

- application intervals and maximu m number of applications. A summary of the uncertainties for each label is presented below in Table 3

.

Table 3 . Summary of Uncertainties for Registered Label for Sulfosulfuron

Product Name (EPA Reg Number) Uncertainty

Maverick/Outrider Herbicide (524

- 500) Maximum number of applications are not defined for: bermudagrass and

bahiagrass non

- crop sites, tall fescue non

- crop sites, pasture and rangeland sites (w. of Mississippi R), native grasses and conservation reserve program, non

crop tree sites, forestry conifer release use Re

- application intervals are not define for: bermudagrass and bahiagrass non

crop sites (hand

- held & high

- volume app ) , tall fescue non

- crop sites, pasture and rangeland sites (w. of Mississippi R), forestry conifer release use Mon 37525 NC/ Mon 37525W

(524

- 526) Maximum number of applications and re

- application interval are not defined for

non

- crop uses for Mon 37525 NC Mon 44940 SC (524

- 533) Maximum number of applications (all uses) and the re

- application interval

(bermudagrass

- for removal of ryegrass only) are not defined. In addition, it is unclear whether the 30 day interval application interval for the other uses is for fall application only or does it apply to year

- round application. Certainty Turf Herbicide (524

- 534) Maximum number of applications and re

- application interval are not defined

for: buttonweed suppression, annual bluegrass control non

- overseeded tur f, annual bluegrass control prior to overseeding turf

### 9

In situations where the label is not clear on maximum number of applications or application interval, conservative assumptions will be made when conducting the exposure assessment. For example, the number of applications will be assumed to be two when the maximum per year is slightly more than the single maximum application. Also, for re

- application interval, the assumed application interval may be the shortest reported application rate for the part icular use. These assumptions may overestimate the exposure concentrations, therefore, it is advantageous to have labels that clearly define maximum number of applications and application intervals.

A national map showing the estimated poundage of sulfos ulfuron used in 2002 is presented in Figure 1

. The map was downloaded from the U.S. Geological Survey (USGS), National Water Quality Assessment Progra m (NAWQA) website. ( http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=02&map=m9125 ; accessed February 25, 2011)

.

Figure 1 . 2002 Estimated Annual Agricultural Use Map for Sulfosulfuron (Source: USGS)

Table 4 below shows the estimates of agricultural uses of sulfosulfuron as of December 1, 2010.

### 10

Table 4

. Screening Level Usage Estimates (SLUA) for Agricultural Uses of Sulfosulfuron as of December 1, 2010.

Crop Lbs. A.I.
1 Fallow, Summer <500
2 Pasture 1,000
3 Wheat 30,000

All numbers rounded.

<500 Less than 500 pounds of active ingredient <2.5 Less than 2.5 percent of crop treated <1 Less than 1 percent of crop treated

SLUA data sources include: USDA

- NASS (United States Department of Agriculture's National Agricultural Statistics Service) Private Pesticide Market Research California DPR (Department of Pesticide Regulation)

Usage information for non

- agricultural uses is not currently available.



## 3.0 Fate of Sulfosulfuron in the Environment

The chemical name for sulfosulfuron is N

- [[(4

- Hydroxy

- 6

- dimethoxy

- 2

- pyrimidinyl) amino] carbonyl]

- 2

- (ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide. EPA Product Chemistry Review Physical/Chemical Properties are listed in Table 5

. The structure of sulfosulfuron is shown in Figure 2 . A summary of the environmental fate data for sulfosulfuron and sulfosulfuron degradation products were presented in the Drinking W ater Assessment dated 05/24/2007 and are presented here in Table 6 . This table also contains calculated Residue of Concern (ROC) chemical properties which are more fully described later in this document.

### 11

Figure 2 . Sulfosulfuron Chemical Structure

The primary routes of sulfosulfuron dissipation will be through leaching, runoff, and spray drift. Sulfosulfuron is highly mobile due to its low sorption affinity as described by the Freundlich sorption isotherm ( K ads 

### ). Sulfosulfuron is an ionic (pK a 

### =3.5) compound and hence will be anion under environmental ly relevant pHs

. The aerobic soil metabolism studies show moderate to slow degradation. No anaerobic soil metabolism study was submitted. H ydrolysis studies show that sulfosulfuron will be persistent in the neutra l and alkaline environment s

. Rapid

a queous photolysis and moderate aerobic aquatic metabolism will contribute to the degradation of sulfosulfuron in surface water. Environmental f ate studies show that mobility and persistence of sulfosulfuron is correlated with pH (more persistent and mobile with increasing pH). Due to its moderate persistence and high mobility in soil, sulfosulfuron has the potential to leach to groundwater. Sulfosulfuron undergoes acid catalyzed hydrolysis where half

- lives are 7 days @ pH4; 48 days @ pH5 168 days @ pH7; 156 days @ pH9) and soil metabolism rates (expressed as half

lives range from 30 (75 for unextractable residues) to 2 2 6 days

. S ulfosulfuron may undergo photodegradation in surface water systems , but is insigni fi cant on soil. In surface water the aqueous photolysis half

- life is 2.47 days. The aerobic aquatic metabolism half

- life is 26.4 days. Sulfosulfuron is not volatile. In the New Chemical Review, EFED determined that sulfosulfuron had a low potential to bioaccumulate and a fish bioaccumulation study was not required. The mobility as defined by the Freundlich sorption isotherm (K ads 

### ) indicated that sulfosulfuron is highly mobile. The K ads 

### ranged from 0.08 to 0.71, the lowest non

- sand was 0 .23 mL/g. Because sulfosulfuron is a weak acid (ionized compound), other soil factors (e.g., mineralogy, clay content) are expected to influence sorption

, Sulfosulfuron can also move off site via spray drift when the pesticide is being applied
Terrestri al field dissipation studies in Washington and California yielded dissipation half

- lives from the soil surface ranging from 13 to 41 days (MRID 44295732)

. For terrestrial field dissipation studies in North Dakota and Texas, the half

- lives were 75 and 13.6 days, respectively (MRID 44295733).

### 12

Table 5

. Physical/Chemical Properties for Sulfosulfuron (Source: EPA Product Chemistry Review) Physical/Chemical Properties (Source: EPA Product Chemistry Review)

Molecular formula: C 16 H 18 N 6 O 7 S 2 Molecular weight: 470.49 CAS Registry No.: 141776

- 32

- 1 Physical State: powder Melting Point: mean range: 180.9

- 184.1 °C Density: 1.55 g/ml (20 ° C) Water Solubility (20 o 

### C): pH 5: 17.60 ± 2.71 mg/L pH 7: 1626.8 ± 39.8 mg/L pH 9: 482.44 ± 8.35 mg/L Vapor Pressure (20 o 

### C): 2.29 x 10 - 10 

### mm Hg

Dissociation Constant: pKa = 3.51 at 20 ° C

Octanol/water Partition Coefficient (Log P) pH 5: 0.81 pH 7:

- 1.01 pH 9:

- 1.37 Stability: Stable (no stability data for metal ions provided)

### 13

Table 6

. General E nvironmental F ate P roperty V alues for S ulfosulfuron

Property Value Data Source

Chemical Name N

- [[4,6

- dimethoxy

- 2

- pyrimidinyl)carbonyl]

- 2

- ) ethylsulfonyl)

- imidazo[1,2

- a]pyridine

- 3

-

sulfonamide

Solubility 17.6 ppm @ pH 5 ; 1627 ppm @ pH 7 ; 4 82 ppm @ pH9 MRID 442957

- 20

Hydrolysis Half

- Life @ 25 C 7 days @ pH4 ; 48 days @ pH5
168 days @ pH7 ; 156 days @ pH9 MRID 442957

- 20

Aqueous Photolysis Half

- Life Sulfosulfuron
2.47 days (sulfosulfuron)

ROC
4.97 days (sulfosulfuron + Sulfonic acid +

sulfone) MRID 442957

- 21

Sulfosulfuron
Aerobic Soil Metabolism Half

- Life [stated to be DT50 values) [ 75*

, 88*

, 92

, 194, 2 2 6 days ] [*extractable residue values in these studies

were 30 and 37 days]

Total Residues of Concern (ROC)
Aerobic Soil Metabolism Half

- Life (ROC = sum of sulfosulfuron + sulfonamide) [calculated by first order linear regression] [100.5, 223, 266.6, 247.6] Sulfosulfuron * mean (3) = 184.0 days; median = 194.0 days

std. = 87.43 days mean (5) = 143. 0 days; median = 92.0 days

std. = 83.64 days
ROC * mean = 209.5 days ; median = 235.3 days

std. = 74.78 days

*these values were calculated using the unextractable residue halflife values MRID 442957

- 31
MRID 442957

- 23

MRID 442957

- 31

Sulfosulfuron Aerobic Aquatic Metabolism half

- life Total System (water + sediment) [3 2

. 7 (river) 20

. 0 (pond)] Total Residues of Concern (ROC) (ROC = sum of sulfosulfuron + sulfonamide) Total System (water + sediment) [3 7

. 7 (river) 30 .8 (pond)] Sulfosulfuron
mean = 26.4 days std. = 8.98 days

ROC

m ean = 34.25 days
std. = 4

. 8 7 days
Limited sulfonamides observed River and Pond System @ 20 C MRID 442957

- 26

A na erobic Aquatic Metabolism DT50 Mean DT50 (sterile water): 126 days MRID 442957

- 25 Mobility Sulfosulfuron
Freundlich K ads [0.36, 0.08, 0.08, 0.23, 0.71] Koc [ 40, 25, 6.6, 5.3, 89]

Sulfonamide
Freundlich K ads [0.52, 2.07, 1.49, 0.91] Koc [ 61, 106 , 261, 223] Sulfosulfuron (ml/g)mean
K ads = 0.29; median K ads = 0.23 mean Koc = 33.2; median Koc = 25.0
Sulfonamide (ml/g)
mean K ads = 1.25; median K ads = 1.20 mean Koc = 162.8; median Koc = 164.0 MRID 442957

- 28

### 14



## 3.1 Metabolites and/or Degradates
Degradation of sulfosulfuron in the environment produces a number of transformation products. The major (>10%) degradation products seen in metabolism studies are primarily the sulfonamide and aminopyrimidine products, as well as the desmethyl product. Several other major degradates are observed in the aqueous photolysis study. The degradates mentioned above are formed through hydrolytic cleavage of the sulfonylurea bond. Degradation of sulfosulfuron in soil or water occurs under acidic, neutral and alkaline conditions; however, degradation occurs most rapidly under acidic conditions. Depending on the pH of the system, the parent sulfosulfuron may be transformed to one of the degradation products. The rate of formation and distribution of the sulfonamide and aminopyrimidine degradates is reflected by the decline in concentration of sulfosulfuron. The major degradation products that were observed in several environmental fate studies and their formation percentage is listed in Table 7 (structures, chemical formulas, and common names are listed in Appendix B

.

Table 7 . Degradation/Metabolite Products Observ ed in Various Studies

Common Name (CAS #, if available) Chemical Name Degradation Process Forming
Metabolite: Percent Formed: MRID

Desmethyl N

- [[(4

- Hydroxy

- 6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]

- 2

- (ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide Aerobic soil metabolism: extractable

- 2.58% and 1.8% of the applied 14 C

- activity at day 360; bound

1.15% and 0.97% of the applied 14 C

- activity at day 360 (This minor route of transformation involves the demethylation of sulfosulfuron to yield desmethyl, whi ch is further degraded to guanidine): 442957

- 23

Aerobic soil metabolism: extractable

- 5.2%, 2.6% and 1.9% of the applied 14 C

- activity at day 100 in 3 soils: 442957

- 31

Aerobic aquatic metabolism: 14 and 13% at day 30, <1% in sterile system only: 442957

- 26

Anaerobic aquatic metabolism: 11.6% and ≤6.3% of the applied dose at day 365; 2.0% in sterile solution at day 365: 442957

- 25

Soil column leaching: 2.7% of applied dose in leachates: 442957

- 27

Sulfamic acid [[(4,6

- dimethyoxy

- 2

-

pyrimidinyl)amino]carbonyl]

- sulfamic acid Aqueous photolysis: 14% at 48 hour, 19% at 96 hours, 21% at 6 days: 442957

- 2 1

Aminopyrimidine 4,6

- dimethoxy

- 2

- pyrimidinamine Hydrolysis: 92% (pH 4), 31% (pH 5), 12% (pH 7), and 15% (pH 9) at 30 days: 442957

- 20

### 15 Aqueous photolysis: 10% at 48 hours, 24% at 96 hours, 28% at 6 days: 442957

- 21

Aerobic soil metabolism: extractable

– 39.92% and 29.33 % of the applied 14 C

- activity; bound 27.10 and 32.96% at day 360: 442957

- 23

Aerobic soil metabolism: 1.7%: 442957

- 26

Soil column leaching: limited mobility

- <2% of applied dose in leachates: 442957

- 27

Anaerobic aquatic metabolism: 13% at day 365 (identified at hydrolysis product): 442957

- 25

Sulfonamide
(63

- 74

- 1) 2

- (ethylsulf onyl)

- imidazo[1,2

- a]pyridine

- 3

- sulfonamide Hydrolysis: 93% (pH 4), 34% (pH 5), 13% (pH 7), and 15% (pH 9) at 30 days: 442957

- 20

Aerobic soil metabolism: Extractable

- 54.69% and 46.66 % (maximum 14 C

- activity) ; bound 15.29 and 14.46% of amount applied at 36 0 days: 442957

- 23

Aerobic soil metabolism: 6.1% : 442957

- 26
Aerobic soil metabolism: 3,7%, 4.4%, and 12.8 % (maximum 14 C

- activity) at day 100: 442957

- 31
Aerobic aquatic system: Minor transformation product (6.1%). (Identified as hydrolysis product): 442957

- 26
Anaerobic aquatic system: Major transformation product 64.9% of 14 C

- activity at day 365 (Identified as hydrolysis product): 442957

- 25
Soil photolysis: irradiated

- 13% at day 14, and 22.6% at Day 30, dark control 24.4% at day 30 ; 442957

- 22
Soil column leaching: 2% of applied dose in leachates: 442957

- 27

Sulfonic acid
(27176

- 87

- 0) 2

- (ethylsulfonyl)

- imidazo[1,2

-

a]pyridine

- 3

- sulfonic acid Aqueous photolysis: 13% at 72 hours, 1 5 % at 96 hours

, 13% at 6 days: 442957

- 21

Aerobic soil metabolism: M inor transformation product (<0.5%): 442957

- 31
Aquatic sediment: Not mentioned in aerobic aquatic systems study: 442957

- 26

Sulfone 2

- (ethylsulfonyl)

- imidazo[1,2

-

a]pyridine Aqueous photolysis: 14% at 24 hours; 28% at 96 hours and 2 1 % at 6 days: 442957

- 21

Urea (4,6

- dimethoxy

- 2

- pyrimidinyl)

-

urea Anaerobic aquatic metabolism: 29.2% (postulated to form due to elevated ammonia in system): 442957

- 25

N

- hydroxy urea N

- (4,6

- dimethoxy

- 2

- pyrimidinyl)

-

N’

- hydroxy

- urea Aqueous photolysis: 13% at 24 hours , 15% at 48 hours, 7% at 96 hours: 442957

- 21

### 16

Oxamic acid 2

- imino

- alpha

- oxo

- 1 (2H)

-

pyridineacetic acid Aqueous photolysis: 12 % at 96 hours; 16% at 6 days: 442957

- 21



### The Residues of C oncern 2 

### (ROC) as determined by the Health Effects Division (HED) are sulfosulfuron and its ethyl sulfone metabolites [including 2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine

- 3

- sulfonic acid ( sulfonic acid ) ; 2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine

- 3

- sulfonamide ( sulfonamide ) ; and 2

- (ethylsulfony1)

- imidazo[1,2

- alpyridine ( sulfone )]. 2 

### Therefore, a total toxic residue (TTR) approach by EFED will be undertaken when assessing exposure to non

- target animals. Sulfosulfuron and the residues of concern (metabolites) were all considered and converted to the common ethyl sulfone mo iety, 2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine . As stated above, calculated environmental fate properties for the Residues of Concern (RoC) are included in Table 6 abo ve.

Plant metabolite formation appears to occur by demethylation and cleavage of sulfonylurea bond. A plant metabolite study was available in which wheat was treated with sulfosulfuron either pre or post emergence at approximately 2 and 5 times the re gistered application rate of sulfosulfuro n. P arent sulfosulfuron residues in wheat plants represented the majority of total residues with the other residues generally representing <10% of the total radioactive residues (T R R), except for wheat straw that wa s exposed to sulfosulfuron pre

- emergence at approximately 5 times the registered application rate . The metabolites in this study that were >10% of the T R R included the sulfonamide and g uanidine metabolite , 23 and 18% of the TRR, respectively

. The report stated that no phytotoxic effects were noted at either treatment rate. 3



## 4.0 Conclusions from Previous Assessments

In October 1998, the Environmental Risk Branch III in the Environmental Fate and Effects Division (EFED) completed a Federal Insecticide, Fung icide, and Rodenticide Act (FIFRA) Section 3 new chemical assessment for use of sulfosulfuron on wheat, forestry and other non

crop sites. 4 

### The review concluded that sulfosulfuron exceeded the level of concern (LOC) for risk to nontarget terrestrial and aquatic vascular plants (risk quotients (RQs) for terrestrial plants: 3

- 133; aquatic vascular plant RQs: 2

- 3), and that sulfosulfuron may pe rsist in the environment under certain conditions. In addition, as an SU herbicide it has a high potential to move off

- site by drift, runoff and via wind

- blown soil particles, and it may contaminate surface waters that may pose a risk to irrigated crops.

2 Health Effects Division (HED) memorandum from Susie Chun and Alberto Protzel to George Kramer; Subj: Sulfosulfuron (Maverick ) in/on Wheat. PP#7F04840. The ad hoc Metabolism Assessment Review Committee Meeting Held on 9/3/98. DP Barcode: D249043, N ovember 23, 1998.
3 Memorandum from Susie Chun in HED to Jim Tompkins in Registration Division; Subj: PP# 7F04840. New Chemical

- Sulfosulfuron (i.e. MON37500, Maverick ) in/on Wheat. Evaluation of Residue Data and Analytical Methods

. MRID#s: 442957

- 02 thru 04, 442957

- 07 thru11, 442957

- 13 thru 14, 442957

- 16 thru 18, 44295735, 44309301 . DP Barcodes: D237683, D239109. Chemical No. 085601. Case No. 288878; September 28, 1998.
4 Memorandum from Raanan Bloom and William Erickson, Environmental Risk Branch III in Environmental Fate and Effects Division to Donald Stubbs, Herbicide Branch in Registration Division; Subj: Sulfosulfuron: New Chemical Environmental Risk Assessment, Chemical: 085601/Company: 000524 Monsanto Agricultural Company, DP barcode: D23 7257, D241674, D241678, D249831, October 30, 1998.

### 17

In July 2007, EFED completed a risk assessment for a Section 3 new use of sulfosulfuron on Bermudagrass and Bahiagrass pastures. 5 

### The assessment concluded use of sulfosulfuron on these pastures is presumed to pose risk to endangered and non

- endangered n on

- target terrestrial plants and aquatic vascular plants. The risk quotients (RQs) for a single application for terrestrial plants exceed the LOC by one to three orders of magnitude (3

- 258). RQs for the seasonal rate are approximately twice that of the si ngle application. No acute or chronic risks were presumed for terrestrial and aquatic animals.

Finally, several Section 18 emergency exception assessments were completed for the use of sulfosulfuron on Bermudagrass hay fields or pastures and for sulfos ulfuron u se on wheat. These Section 18 requests were from 1997 to 2006, and included the states: Oregon, Washington, Idaho, Oklahoma, Georgia, Louisiana, Arkansas, and Texas. Again, these assessments concluded the potential for risk to endangered and non

- endangered terrestrial plants and aquatic vascular plants. 6



## 5.0 Ecological Effects

The Agency evaluates the potential for adverse e ffects to non

- target terrestrial and aquatic organisms as a result of sulfosulfuron usage. As described in the Agency’s Overview Document (US EPA, 2004), the most sensitive endpoint for each taxon is used to estimate potential risks

. Assessment endpoints include direct toxic effects on the survival, reproduction, and growth of
terrestr ial and aquatic life, as well as indirect effects, such as reduction in prey base and/or modification of habitat. The evaluated taxa include freshwater fish, freshwater aquatic invertebrates, birds, small mammals, terrestrial invertebrates, algae, and ter restrial plants.

Acute (short

- term) and chronic (long

- term) toxicity information is characterized based on registrant

- submitted studies and a comprehensive review of the open literature on sulfosulfuron

. Currently, an open literature ECOTOX search has not been conducted at this time, however this search will be conducted and a review of open literature studies will be conducted for potential use in the registration review ecological risk assessment. Other sources of information, including use of the ac ute probit dose response relationship to establish the probability of an individual effect and reviews of the Ecological Incident Information System (EIIS), are conducted to further refine the characterization of potential ecological effects associated wit h exposure to sulfosulfuron . A summary of the available ecotoxicity information and the incident information for sulfosulfuron are provided below. A summary of the studies are presented in Appendix C

.

5 Memorandum from James Wolf and Stephen Carey, Environmental Risk Branch III in Environmental Fate and Effects Division to James Tompkins, Herbicide Branch in Registration Division; Subj: Ecological Risk assessment for Section 3 New Use (R17.3) of Sulfosulfuron on Bermudagrass and Bahiagrass pastures; DP barcode: D327364, July 26, 2007.

6 From assessments with the following DP barcode: D304290, D304476, D304659, D312625, D328236; also from memorandums f

rom EFED to Minor Use, Inerts and /or Emergency Response Branch on August 11, 1997 and September 17, 1998.

### 18



## 5.1 Terrestrial Organism Toxicity Data

Table 8 sum marize s the most sensitive ecological toxicity endpoints based on currently availa ble data for terrestrial organisms . A brief summary of submitted data considered relevant to this ecological risk assessment is presented below

.

Table 8

. Most Sensitive Terrestrial Organism Toxicity Values for Sulfosulfuron Based on Available Data

Assessment Endpoint Measures of

Effect Species Toxicity Value MRID Number; Reference ; and Study Classification Abundance (i.e., survival, reproduction, and growth) of individuals and populations of birds Avian acute

oral (single dose) 14

- day LD 50 Northern bobwhite

quail (Colinus virginianu s ) LD 50 > 2250 mg a.i. /kg

- bw

NOAEC = 810 mg a.i./kg

- bw (based on clinical signs of toxicity) 44295768; Campbell and Beavers, 19 94; Acceptable Avian subacute 5

- day dietary LC 50 Mallard duck

( Anas platyrhynchos 

## ) LC 50 > 5110 mg a.i./kg

- diet

NOAEC (observed) = 3000 mg a.i./kg

- diet (based on body weight) 44295771; Campbell and Beavers,19 94; Acceptable

Avian
rep roduction NOAEC Mallard duck

( Anas platyrhynchos 

## ) NOAEC = 245 mg a.i./kg

- diet

(based on 14

- d old body weights) 44295773; Frey et. al

, 199 6; Acceptable

Abundance (i.e., survival, reproduction, and growth) of individuals and populations of mammals Mammalian

acute oral (single dose) 14

- day LD 50 Rat ( Rattus

norvegicus ) L D 50 > 5000 mg/kg

- bw

(M ale &F emale ) (1) 44295737; Bonnette , 19 93; Acceptable

Mammalian 2

- generation rat reproduction NOAEL Rat ( Rattus

norvegicus ) NOAEL = 5,000 mg/kg

- diet

( 312 mg/kg/day) (2) (based on decreased body wt in offspring and paternal toxicity) 44295758; Naylor and Thake ,19 96; Acceptable Survival of beneficial insect populations Honey bee

acute contact LD 50 Honey bee ( Apis mellifera ) LD 50 = >25 μg a.i./bee

NOAEL = 25 μg a.i./bee 44295788; Palmer and Beavers, 1994; Acceptable Honey bee acute oral LD 50 Honey bee ( Apis mellifera ) LD 50 = >29.6 μg a.i./bee ( 3 )

NOAEL = 29.6 μg a.i./bee ( 3 ) 44295789; Palmer and Beavers, 1995; Acceptable Survival and growth of terrestrial plants Seedling

Emergence Monocot: Onion

( Allium cepa ) EC 25 = 7.7x10 - 4 lb a.i./A ( 4 )

EC 05 = 1 .0 x 10 - 4 lb a.i./A 44295783; Chetram and Cone, 1997; Supplemental Dicot: Radish ( Raphanus sativus ) EC 25 = 7.1 x10 - 4 lb ai/A

NOAEC = 0.001 lb a.i./A ; EC 05 = 9.2 x10 - 5 Vegetative Vigor Monocot:

Ryegrass ( Lolium
perenne ) EC 25 = 0.00 34 lb ai/A (5)

NOEC = 0.0020 lb a.i./A 44295784; Chetram and Cone, 1995; Supplemental Dicot: Radish ( Raphanus sativus ) EC 25 = 8.4 x10 - 5 lb ai/A

NOAEC = 3.1 x 10 - 5 lb a.i./A

### 19

1Product tested contained 98.9% active ingredient (Technical Grade); O ne female lost weight from Day 8 to 15

. 2 Product tested contains 98.4 % active ingredient (Technical Grade). 3 Product tested contained >98.5% active ingredient (Technical Grade); reviewer adjusted reported LD 50 value for purity

. 4 Values based on most sensitive endpoint of dry weight. Study was not conducted using a TEP, rather tested using TGAI (98.4 % ) ; solutions prepared using deionized water. There is uncertainty in the EC25 value for the most sensitive dicot, radish, as the data for the most sensitive endpoint, dry weight, did not provide a reliable EC25 value as it was lower than the NOAEC value

. 5 Values based on most sensitive endpoint of dry weight. Study was not conducted using a TEP, rather tested using TGAI (98.4 % ) ; solutions prepared using deionized water.



### 5.1.1 

## Avian Toxicity, Acute

Sulfosulfuron is classified as practically non

- toxic to birds as the acute oral LD 50 

### is >2,250 mg a.i./kg

- bw for both bobwhite quail and mallard ducks (MRID 44295 768 and 44295769). In the bobwhite quail acute oral study, signs of toxicity were observed at the two highest test doses and an effect on body weight gain at the highest dose; therefore, the NOAEL for the bobwhite quail study was determined to be 810 mg a .i./kg

- bw. No sublethal effects were observed in the mallard duck acute oral study. The 5

- day subacute dietary LC 50 

### value for the bobwhite quail and mallard duck is >5,570 mg a.i./kg

- diet and >5,110 mg a.i./kg

- diet, respectively, and therefore are classi fied as practically non

- toxic (MRID 44295770 and 44295771). No sublethal effects were observed in the bobwhite quail study. A slight reduction in body weight was observed at the highest concentration tested for the mallard duck; therefore, the NOAEC (obs erved and not statistically derived due to lack of replication) is 3,000 mg a.i./kg

- diet. In the previous Data Evaluation Record (DER), the reviewer based the toxicity values on the mean measured concentrations of the treated feed at test initiation. As Day 5 test dietary feed were analyzed to determine stability, these concentration values were included in determination of the overall mean measured dietary concentration and the LC 50 

### and NOAEC values reported in this problem formulation reflect these chan ges.

Acute oral toxicity data with a passerine species was not available.

5.1.2 

## Avian Toxicity, Chronic

Two studi es were available for evaluating the effects of chronic exposure to sulfosulfuron on birds. Adult bobwhite quail and mallard ducks were exposed to nominal dietary concentrations of 50, 250 and 1,250 mg a.i./kg

- diet. For the bobwhite quail reproduction study, no observed effects on survival, growth or reproduction were observed at the highest concentration tested and the NOAEC value is 1,229 mg a.i. /kg

- diet (mean

- measured) (MRID 4429572). For the mallard duck reproduction study, there was an effect on the body weight of 14

- day old hatchlings at the highest concentration tested (MRID 4429573). Therefore, t he chronic NOAEC for birds is 245 mg a.i./kg

- diet, and the LOAEC is 1,221 mg a.i./kg

- diet (mean

- measured)

. In the previous avian reproduction DERs, the toxicity values were based on nominal concentrations. As diet concentrations were analyzed periodically throughout the test, an overall mean measu red dietary concentration was calculated and the toxicity values reported in the problem formulation reflect this change.

### 20

5.1.3 

## Mammal Toxicity, Acute The acute oral LD50 toxicity value for mammals using technical grade sulfosulfuron (based on a rat study) is > 5,000 mg/kg

- bw (98.9 % a.i.) (MRID 44295737). One female lost weight between Day 8 and 15 (249 versus 252 grams); all other animals gained weighed during the study. Clinical findings included soft/mucoid stools on days 1

- 3 post dosing. The observed sli ght weight loss in one out of ten animals does not appear to indicate a treatment

- related effect.

There were two reported acute oral rat studies using sulfosulfuron formulations. Both were limit tests and resulted in an acute LD 50 

### value of > 5,000 mg/kg

- bw. One study tested MON 37532 (73.7% a.i.) and the other study tested MON 37525 (23.7% a.i.) (MRID 44295738 and MRID 45116102).

Sulfosulfuron is also not a mammalian dermal or skin irritant or skin sensitizer (MRIDs 44295739, 44295743 and 44295739). It is a moderate eye irritant (MRID 44295741).

The HED CARC classified Sulfosulfuron as “Not Likely to be Carcinogenic to Humans” at doses that do not cause crystals with subsequent calculi formation resulting in cellular damage of the urinary tract. (MRID 44295759 and 44295755; Kidwell December 16, 2008). Sulfosulfuron is not expected to be mutagenic.

5.1.4 

## Mammal Toxicity, Chronic

A 2

- generation reproduction study with rats was available (MRID 44295758). The NOAEL is 5,000 mg/kg (312.1 mg/kg/day), based on decreased parental and offspring body weight gain, mortality in the parental males, and urinary tract pathology in parental gen eration observed at a concentration of 20,000 mg/kg (1,312.8 mg/kg/day) (LOAEL).

5.1.4.1 

## Mammalian Metabolism Data A metabolism study, with rats using radiolabelled sulfosulfuron (MON 37500) (98% a.i.) was available (MRID 44295765). M ore than 90% of the adm inistered radioactivity was excreted by 72 hrs post

- dosing (mean total recovery ranged from 97% to 101%). Between 77 to 87% was excreted in the urine in the low doses, whereas feces were the major route of elimination at the high dose (55

- 63%). In all do se groups, minimal radioactivity was retained in tissues (less than 0.07%) or carcass (less than 0.17%). Metabolism of MON 37500 in all groups was minimal and most was excreted unmetabolized (for example, it represented more than 90% of the total radioact ivity excreted in the urine). MON 37500 was metabolized primarily via ring hydroxylation of the a

- position carbon of the pyrimidine ring, or demethylation of the methoxy group at the 4

- or 6

- position of the pyrimidine ring. In addition, a limited amount of cleavage of the sulfonamide bond into sulfonamide or other imidazopyridine compounds and pyrimidine compounds was observed. Major metabolites identified in urine and feces were desmethyl MON 37500 (3.6% or greater of administered dose), 5

- hydroxy MON 3 7500 (1.9% or greater) and sulfonamide (2.6% or greater). A fourth, Feces 488 (ND

- 1.68%; feces only), was partially

### 21

characterized as a desmethylated metabolite. Other minor metabolites, 1 imidazopyridine and 3 pyrimidine metabolites, were also found at low levels (<1%) in the feces.

5.1.5 

## Terrestrial Invertebrate Toxicity, Acute

The acute contact honeybee LD50 value is reported to be >25 μg a.i./bee (MRID 44295788). There were a few reported incidences of sublethal effects observed (i.e., loss of equilibrium, immobility) in the two highest treatment groups, but these incidences and overall mortality in the treatment groups was less than the controls. Therefore, the NOAEL is reported to be 25 μg a.i./bee.

An acute oral toxicity test with the honey bee is also available (MRID 44295789) for sulfosulfuron. The 48

- hour acute oral LD50 was >29.6 μg a.i./bee. The NOAEL is reported as 29.6 μg a.i./bee, as there was mortality observed at the highest dose tested, but was lower than reported in the negative control. The doses tested in this study were not adjusted for sulfosulfuron purity (98.5%), and the DER did not adjust the reported values for purity. Therefore, the doses were adjusted for purity and the toxicity values reported in this document reflec t this change.

5.1.6 

## Terrestrial Plant Toxicity

Both a seedling emergence and a vegetative vigor study using sulfosulfuron were submitted by the registrant (MRID 44295783 and 44295784). These studies were conducted using technical grade sulfosulfuron (98.4%) which was dissolved in deionized water. Terrestrial plant studies conducted using a typical end

- use product (TEP) were not available, and as sulfosulfuron is a herbicide there is uncertainty in how the other ingredients in the formulations may influence t he overall toxicity to terrestrial plants. As such, the submitted studies were reclassified from Acceptable to Supplemental, and additional studies conducted using a TEP are requested.

Based on the most sensitive species and endpoints reported, sulfosu lfuron is more toxic to dicot terrestrial plants in the vegetative vigor study compared to the se edling emergence study. However, monocots appear to be more sensitive in the seedling emergence test than the vegetative vigor study. The seedling emergence EC 25 

### for the most sensitive dicot ( radish ) and monocot ( on ion) are 7.1 x 10 - 4 

### and 7.7x10 - 4 

### lb a

. i

. /A, respectively. The corresponding NOAEC or EC 05 

### for these species is 1.0 x 10 - 4 

### and 0.001 lb a.i./A, respectively. There is uncertainty in the EC 25 

### value for the dicot, radish, as the data for the most sensitive endpoint, dry weight, did not provide a reliable EC 25 

### value as it was lower than the calculated NOAEC value

. As such, this uncertainty also contributed to the reclassification of the seedling emerg ence study. The dry weight values for onion and radish were re

- calculated using Nuthatch and presented in a memo from EFED on March 4, 1999 (Erickson), and these values were used for reporting the EC 25 

### and NOAEC/EC 05 

### values..

### 22

The vegetative vigor EC 25 

### for the most sensitive dicot ( radish ) and monocot ( ryegrass )

are 8.4 x 10 - 5 

### and 0.0034 lb ai/A, respectively. The corresponding NOAEC for these species is 3.1 x 10 - 5 

### and 0.002 lb a.i./A, respectively. The dry weight EC 25 

### and NOAEC/EC 05 

### values for radish and ryegrass were re

- calculated using the model Nuthatch. The guideline seedling emergence and vegetative vigor studies reported non

- lethal effects of s ulfosulfuron exposure on plants such as chlorosis, stunting, restriction of leaf expansion and apical m eristem growth.



## 5.2 Aquatic Organism Toxicity Data

Table 9 sum marize s the most sensitive ecological toxicity endpoints based on currently available data for aquatic organisms . A brief summary of submitted data considered relevant to this ecological risk assessment is presented below

.

### 23

Table 9

. Most Sensitive Aquatic Organism Toxicity Values for Sulfosulfuron Based on Available Da ta

Assessment Endpoint Measures of

Effect Species Toxicity Value MRID Number; Reference; and Study Classification Survival and reproduction of individuals and communities of freshwater fish Freshwater fish

acute 96

- hr LC 50 Rainbow trout

( Oncorhynchus mykiss ) LC 50 > 93.6 mg a.i./L (1)

NOAEC = 93.6 mg a.i./L 44295774; Graves and Swigert, 1994; Acceptable Freshwater fish early life

- stage NOAEC Rainbow trout

( Oncorhynchus mykiss ) NOAEC = 100 mg a.i./L; highest

concentration tested 44295779; Graves, Mank and Swigert, 1996; Acceptable Survival and reproduction of individuals and communities of freshwater invertebrates Freshwater

invertebrate acute 48

- hr LC 50 Water flea

( Daphnia

magna ) EC 50 > 94.6 mg a.i./L (1)

NOAEC = 94.6 mg a.i./L 44295776; Graves and Swigert, 1994; Acceptable Freshwater invertebrate reproductive NOAEC Water flea

( Daphnia

magna ) NOAEC = 102 mg a.i./L; highest

concentration tested 44295780; Graves, Mank and Swigert, 1996; Acceptable Survival and reproduction of individuals and communities of estuarine and marine fish Estuarine and

marine acute fish 96

- h LC 50 Sheepshead

minnow ( Cyprinodon variegat us ) LC 50 > 101 mg a.i./L

NOAEC = 101 mg a.i./L 44309304; Graves and Swigert, 1995; Acceptable Estuarine and marine fish reproductive NOAEC No Data Available; Using acute to chronic ratio (ACR):

NOAEC = 8.78 mg a.i./L (2); ECOSAR Fish Chronic Value = 20.9 mg/L

Survival and reproduction of individuals and communities of estuarine and marine invertebrates Estuarine and

marine invertebrate
acute 96

- hr LC 50 Mysid Shrimp

( Mysidopsis bahia) L C 50 > 106 mg a.i./L

NOAEC = 106 mg a.i./L 44295777; Graves and Swigert, 1995; Supplemental

Estuarine and marine invertebrate reproductive NOAEC No Data Available; Using acute to chronic ratio (ACR) from other SU

data: NOAEC = 5.73 mg a.i./L; Using ACR using ECOSAR Daphnia

data : NOAEC = 9.8 mg/L (3)

Standing crop or biomass and growth of aquatic plants Freshwater

green algae, cyanobacteria or diatom 120

- h IC 50 for biomass. Green algae

( Selenastrum capricornutum ) IC50 = 0.3 1 0 mg a.i./L

(310 μg a.i./L) ( 4 )

NOAEC = 0.093 mg a.i./L (93 μg a.i./)

Based on endpoint of area under the curve 44295785; Thompson and Swigert, 1995; Supplemental (not for quantitative use in risk assessment)

Vascular aquatic plants Duckweed

( Lemna gibba) EC50 ≈ 9.85 x 10 - 4 mg a.i./L

( 0.985 μ g a.i./ L) (5)

NOAEC = 4.9 x 10 - 4 mg a.i./L ( 0. 49 μ g a.i./ L)

Based on Frond Number 44295787; Thompson and Swigert, 1996; Supplemental (not for quantitative use in risk assessment)

### 24

1 Technical Grate Active ingredient reported to be >98.5 % (Rainbow trout) or 98.5% (Daphnia); reviewer adjusted reported value for purity. 2 ECOSAR values for Imidazoles were Fish 96 hr LC50

– 240 mg/L and Fish Chronic Value of 20.9 mg/L; ACR = 240 ÷ 20.9 = 11.5

. 3 Acute to chronic ratio calculated using endpo ints for ECOSAR value for Sulfonyl ureas were Daphnia 48

- hr LC50 value of 558 mg/L and a Daphnia Chronic Value of 51.6 mg/L; ACR = 558 ÷ 51.6 = 10.8; 106 ÷10.8 = 9.8 mg/L

. ACR using chlorsulfuron (PC 118601) acute and chronic data: acute EC50 = 370 ppm (MRID 00035262) and chronic NOAEC = 20 ppm (MRID 41976404), ACR = 370 ÷ 20 = 18.5; 106 ÷ 18.5 = 5.73 ppm 4 Technical Grate Active ingredient reported to be > 98.5 %; reviewer adjusted reported value for purity. Most sensitive endpoint was area under the cu rve. Four out of the six concentrations tested were not analyzed during the study due to being below the LOQ, therefore nominal concentration were used. Therefore IC50 and NOAEC values fall within the range of concentrations that were not analyzed. 5 Tec hnical Grate Active ingredient reported to be > 98.5 %; reviewer adjusted reported value for purity (98.5)

. Most sensitive endpoint was frond number; dry weight was not reported. Frond number inhibition at highest concentration tested compared to the cont rol was 50%, therefore there is uncertainty in the reliability of the EC50 value. All concentrations tested were not analyzed during the study due to being below the LOQ, therefore nominal concentration were used. Stock used to make test solutions analyz ed but this stock was 1000 times greater than test concentrations. Therefore EC50 and NOAEC values based on concentrations that were not analyzed.



### 5.2.1 

## Fish Toxicity Data, Acute Available acute toxicity data for freshwater and estuarine

- marine fish indicate that sulfosulfuron is essentially practically non

- toxic on an acute exposure basis (MRID 44295774, 4429575, and 44309304)

. The practically non

- toxic classification include LC 50 

### values greater than 100 mg/L; however, for freshwater fish, ther e was no mortality observed at concentrations of 93.6 mg a.i./L or greater, therefore, sulfosulfuron classification is considered to be essentially practically non

- toxic to freshwater fish. The LC 50 

### values for the freshwater rainbow trout and bluegill sunfish are > 93.6 and 94.6 mg a.i./L, respectively. The LC 50 

### value for the estuarine

marine sheepshead study was > 101 mg a.i./L. No sublethal effects were observed in any of the freshwater or estuar ine

- marine studies. The study report nor the DER adjusted the test concentrations for purity of sulfosulfuron for the rainbow trout or bluegill sunfish studies (98.5%), therefore, the reported toxicity values in this assessment are adjusted for purity.

5.2.2 

## Fish Toxicity Data, Chronic

An early

- life stage toxicity test was available for the freshwater fish, rainbow trout ( MRID 44295779). The 60

- day post hatch early

- life cycle study resulted in a NOAEC value of 100 mg a.i./L, the highest concentration teste d, as no adverse effects were observed.

Chronic toxicity data for estuarine

- marine fish was not available. As such, the acute to chronic ratio (ACR) method was used to estimate chronic toxicity for estuarine

- marine fish. However, for sulfosulfuron, as a non

- definitive acute toxicity value was reported for the rainbow trout in which a chronic NOAEC value was reported, the use of this toxicity data to establish an ACR is not appropriate. A search of toxicity data for other sulfonylureas was conducted usi ng the EFED Ecotoxicity database, but no other chemical had both appropriate acute and/or chronic data (e.g., acute non

- definitive toxicity values and/or no chronic data). The quantitative structure activity relationship model ECOSAR v1.00 (EPI suite, EPA 2008) was used to try to estimate

### 25

chronic fish toxicity 7 

### . Using the acute sheepshead minnow data and an ECOSAR ACR of 11.5, an estimated chronic toxicity value for estuarine marine fish was 8.78 mg/L. 8 

### This chronic value calculated using an ACR may be conservative as there was no mortality observed in the acute toxicity test at the limit dose, which was used in the derivation of the ACR, for the sheepshead minnow. Therefore, this acute limit dose does not accurately reflect a definitive LC 50 

### value.

5.2.3 

## Aquatic Invertebrate Toxicity Data, Acute

Both freshwater and estuarine

- marine acute toxicity data was available (MRID 44295776, 44297577 and 44295778). The reported freshwater, Daphnia magna , acute EC 50 

### value was >94.6 mg a.i/L. The estuarine

- marine , mysid shrimp, acute LC 50 

### value was >106 mg a.i./L. Again, as with the fish, sulfosulfuron is considered to be classified as practically non

- toxic to aquatic invertebrates. No sublethal effects were reported in either study. The exact age of the organi sms used in the mysid shrimp study were not reported, rather that they were juveniles. As such, this study is classified as Supplemental, but could be upgraded with submission of acceptable information. In addition, for the Daphnia study, neither the stu dy authors nor the DER adjusted the toxicity values for purity (98.5%); the toxicity value reported in this document has been adjusted for purity. An oyster shell growth study was also available (MRID 44295778). No effect on shell growth was observed at the limit concentration of 116 mg a.i./L compared to the control. No sublethal effects were reported.

Sediment organism acute (short

- term) toxicity data was not available.

5.2.4 

## Aquatic Invertebrate Toxicity Data, Chronic

A chronic toxicity study with Daphni a magna was available (MRID 44295780). The reported NOAEC was 102 mg a.i./L, the highest concentration tested.

No chronic toxicity data was available for estuarine

- marine invertebrates. As such, a similar approach was used as described above for estuarin e

- marine fish. The freshwater invertebrate data for sulfosulfuron is not appropriate to calculate an ACR due to the non

- definitive acute toxicity value for the Daphnia. A review of toxicity data for other sulfonylureas indicated that the chemical, chlorsu lfuron (PC 118601) had definitive acute and chronic freshwater toxicity data. 9


### The estimated estuarine

- marine invertebrate chronic toxicity value using the acute toxicity data and the chlorsulfuron ACR is 5.73 mg/L. The model ECOSAR was also used to eval uate chronic

7 Based on the SMILES data for sulfosulfuron, ECOSAR returned fish toxicity data for two classes : imidazole (an aromatic heterocyclic diazole (five

- membered ring consisting of three carbon atoms and two nitrogen atoms)) and amides (carbonyl group (R

- C=O) linked to a nitrogen atom). The imidazole fish data was used to report chronic fish toxicity and calculate ACR. The chronic fish toxicity data repo rted in ECOSAR was predicted using an ACR.
8 The chronic fish toxicity value reported was 20.9 mg/L. The fish 96

- hr acute LC 50 value reported was 240 mg/L; ACR = 240 ÷ 20.9 = 11.5.
9 The acute 48

- hr EC50 value is 370 mg/L (MRID 00035262), and the 21

- day c hronic NOAEC value is 20 mg/L (MRID 41976404); ACR = 370 ÷ 20 = 18.5

### 26

toxicity to estuarine

- marine invertebrates. The estimated chronic toxicity value for estuarine

marine invertebrates using the acute mysid LC 50 

### and the ECOSAR ACR is 9.8 mg/L. 10 

### Again, this calculated chronic value using the ACR may be conserv ative for the same reasons as described above for the chronic sheepshead minnow value.

Sediment organism chronic (long

- term) toxicity data is not available.

5.2.5 

## Aquatic Plant Toxicity Data

Aquatic vascular plants appear to be more sensitive than any of the aquatic nonvascular plants tested. The 14

- day EC 50 

### and NOAEC for the freshwater vascular plant ( Lemna gibba

, duckweed) for frond count (most sensitive endpoint reported) was approximately 0.985 and 0.49
μg a.i. /L, respectiv ely (MRID 44295777)

. A significant percentage increase in the number of dead and chlorotic frond at the highest concentration (0.985 μg a.i. /L ) was observed compared to the control. The frond number percent inhibition at the highest concentration tested (0.985 μg a.i. /L ) was 50% compared to the control; therefore, there is uncertainty regarding the precision in the EC 50 

### value. These toxicity v alues are based on nominal test concentration as none of the test concentrations were analyzed for sulfosulfuron due to the test levels being below the LOQ (0.75 mg a.i./L). The stock (1.0 mg a.i./L) used to prepare the test solutions was analyzed at tes t initiation and was 97

– 100% of nominal. However, the same 1.0 mg a.i./L solution which was retained for 14 days to evaluate stability was 66% of nominal on Day 14. The test solutions were not renewed during the 14 day test duration. This stock soluti on is 1000 times greater than the highest concentration tested (1.0 μg/L; 0.985 μg a.i./L), therefore there is great uncertainty in the actual concentrations in the test system in which the duckweed where exposed to. In addition, dry weight was not reporte d which may have been a sensitive endpoint. As neither the study author nor the DER adjusted the test concentrations for purity, the reported values in the problem formulation were adjusted. Given the uncertainties in the actual exposure concentrations a nd the EC 50 

### value, this study was reclassified as Supplemental, for qualitative use only. An additional study using Lemna gibba is requested.

Toxicity data was available for four different non

- vascular plant species for sulfosulfuron (MRIDs: 44295781, 82 , 85 and 86). The green

- algae

, Selenastrum capricornutum

, 

### was the reported most sensitive non

- vascular plant tested with EC 50 

### and NOAEC values of 310 and 93
μg a.i. /L , respectively, based on the area under the curve endpoint

. Four out of the six
concent rations tested were not analyzed during the study due to being below the LOQ, therefore nominal concentration were used for these concentrations. The EC 50 

### and NOAEC values fall within the range of test concentrations that were not analyzed. The measured concentrations for the two highest concentrations tested were 82 and 83% at test initiation and 64 and 86% at test termination

. The DER reported the toxicity based on cell density alone and did not verify growth rate, area under the curve and yield. Ther efore, these endpoints were analyzed using the EFED Nuthatch model. In addition, neither the study author nor the DER adjusted the test concentrations for purity; therefore the reported values in the problem formulation were adjusted.

10 The acute 48

- hr LC50 value for Daphnia for the sulfonyl urea class in ECOSAR was 558 mg/L and the chronic value was 51.6 mg/L; ACR = 558 ÷ 51.6 = 10.8.

### 27

Although, the measu red test concentrations for the two highest concentrations were within 80

- 120% of nominal at test initiation, given the stability at the highest concentration and relative instability at the next lower concentration there is uncertainty in the actual expos ure concentrations in the remaining lower concentrations. Therefore, there is uncertainty in which approach is appropriate when determining how to report the exposure concentrations used for statistical analysis. As such this study is reclassified as Sup plemental , for qualitative use only and an additional study is requested.

There were three other non

- vascular toxicity studies conducted using sulfosulfuron. The reported EC 50 

### value for the marine diatom, S keletonema costatum , and the freshwater diatom, Navicula pelliculosa

, is >103 and > 87 mg a.i./L, respectively. Particulates were observed in the solution used to make the test solutions for both studies and an effort to remove these particulates prior to analysis was not reported. Therefore, there is uncertainty in the actual exposure concentrations. The toxicity values for these studies will be reported as mg a.i. (total)/L to indicate the possibility of the measured values reporting both dissolved and undissolved test material. These studies were r eclassified as Supplemental. However, given the large difference between the observed toxicity (>200 fold difference) in these two studies compared to the green algae or cyanobacteria, additional studies are not requested at this time.

The final non

- vas cular aquatic plant study was conducted on cyanobacteria (blue

- green algae), Anabaena flos

- aquae , with a reported EC 50 

### and EC 05 

### value of 0.56 and 0.038 mg a.i./L or 560 and 38 μg a.i./L, respectively, based on area under the curve endpoint. The DER reporte d the toxicity based on cell density alone and did not verify growth rate, area under the curve and yield. Therefore, these endpoints were analyzed using the EFED Nuthatch model. As with the two diatom studies, particulate matter was observed in the stoc k solution used to prepare the test concentrations, and methods to remove this material prior to analysis was not reported; therefore, the toxicity values will be reported as mg a.i. (total)/L. In addition, the two lowest test concentrations were not anal yzed as they were below the LOD (1.0 mg a.i./L), and as such, both the calculated EC 50 

### and EC 05 

### fall within the concentration range that was not analyzed. The measured concentrations for the remaining test concentrations ranged from 100 to 106% of nominal , suggesting the sulfosulfuron was stable in the test system. As there was observed particulate matter, no measurement of the all test concentrations, and the most sensitive EC 50 

### value is close to the reported EC 50 

### value of the most sensitive non

- vascular species test, an additional tested with Anabaena flos

- aquae is requested. This is to better ensure that the most sensitive endpoint for the most sensitive non

- vascular species is used in the risk assessment. This study was reclassified as Supplemental.



## 6.0 Evaluation of Non

- definitive Toxicity Values

All of the acute terrestrial and aquatic animal studies resulted in non

- definitive toxicity values. In an effort to determine whether additional data is needed to evaluate risk to these taxa, a comparison of the non

- definitive toxicity value to either an aquatic EEC or terrestrial EEC was conducted. According the current registered sulfosulfuron labels, the maximum annual application rate is 0.125 lb a.i./A (EPA Reg # 524

- 534, 524

- 500, and 524, 533). This is slightly more than the maximum single application rate of 0.094 lb a.i./A (EPA Reg # 524

- 534 and 524

-

### 28

500). Although the maximum annual rate is slightly higher, it will provide conservative EEC values to compare to the toxicity data.

GENEEC2 (US EPA, 200 1) was used to estimate the parent sulfosulfuron concentrations in surface water for aquatic exposure to fish and invertebrates. GENEEC2 estimates the peak value which occurs on the day of the single large rainstorm as well as multiple day averages over
p eriods of 4, 21 and 60 days. These averages are appropriate for comparison with toxicity tests currently performed. A single application rate of 0.125 lb a.i./A was used as the application input. The Tier I EECs for parent sulfosulfuron are 6.8, 5.2, and 4.6 μg a.i./L

, the peak, the 21

- day and the 60

- day averages, respectively. The output file is presented in Appendix D

.

The lowest acute non

- definitive toxicity valu es for freshwater fish (rainbow trout) and estuarine

- marine fish (sheepshead minnow) are 93.6 and 101 mg a.i./L, respectively. The lowest

non

- definitive toxicity values for freshwater invertebrates ( Daphnia magna ) and estuarine

marine invertebrates (mysid shrimp) are 94.6 and 106 mg a.i./L, respectively. No sublethal effects were observed at these concentrations. The calculated peak EEC concentration is 6.8 μg a.i./L. As such, the non

- definitive toxicity values for fish and invertebrates are > 10,000 ti mes the peak EEC. 11



### For terrestrial animals, the model T

- REX v1.4.1 (US EPA, 2008) was used to model sulfosulfuron residues on terrestrial plants and insects. A single application rate of 0.125 lb a.i./A was used as the input application rate. The maximum upper

- bound dietar y based EEC for birds and mammals is 30 mg a.i./kg

- diet. The maximum upper

- bound dose based EEC for birds (20

- g) is 34.17 mg a.i./kg

- bw; the maximum upper

- bound dose based EEC for mammals (15

- g) is 28.60 mg a.i./kg

- bw. The upper

- bound EEC for small insec ts is 16.88 mg a.i./kg. The output file is presented in Appendix E

.

The lowest acute non

- definitive values for birds are 2,250 mg a.i./kg

- bw for acute oral and 5,110 mg a.i./kg

- diet for subacute dietary; the corresponding NOAEL or NOAEC values for these studies is 810 mg a.i./kg

- bw and 3,000 mg a.i./kg

- diet, respectively. The acute non

definitive value for mammals is 5,000 mg a.i./kg

- bw. As the acute oral toxicity v alues are based on body weight, the NOAEL value for the avian acute oral and the non

- definitive mammal value were entered into T

- REX to obtain the adjusted toxicity value for the small weight bird or mammal assessed in T

- REX. The adjusted toxicity value fo r birds (20

- g) is 584 mg a.i./kg

- bw, and for mammals (15

- g) is 10,989 mg a.i./kg

- bw. The acute toxicity values for birds and mammals are at least 17 times the EEC. 12



### The non

- definitive acute contact honeybee value is presented in μg a.i./bee and therefor e can not be directly compared to the EECs. The toxicity value was converted to mg/kg by dividing the value by the weight of one bee (0.128 g) which calculates to a toxicity value of 195 mg a.i./kg (Mayer and Johansen, 1990). This toxicity value is appro ximately 11.5 times the EEC. The acute oral toxicity study with honeybees also resulted in a non

- definitive endpoint. Currently, there is not a formalized process in EFED by which to evaluate risk from oral pesticide exposure to honeybees or other terres trial invertebrates. One approach to evaluate risk

11 For the lowest acute aquatic va lue of 93.6 mg a.i./L (rainbow trout): 93,600 ÷ 6.8 = 13,765
12 For the lowest ratio for acute terrestrial animals (acute avian oral): 584 ÷ 34.2 = 17

### 29

to at least terrestrial invertebrates that consume plants is to convert the reported toxicity value from μg a.i./bee to a dietary based endpoint (mg a.i./kg) by using the sucrose solution that the bees fe d upon. In this study, 300 mg of test material was added to obtain a final volume of 100 mL in a 50% sucrose solution. Therefore, the concentration was 300 mg/100 mL or 3,000 mg/kg. If adjusted for purity (98.5%), the value is 2,955 mg a.i./kg. A compa rison of this value to the residue concentration for short grass, (highest EEC) could be conducted. The calculated short grass EEC, based on current application rates, is 30 mg a.i./kg. The calculated toxicity value is approximately 100 times greater tha n the calculated EEC.

Therefore, based on these comparisons of toxicity values to calculated EECs using the currently registered labels, additional toxicity data for these endpoints is not requested at this time. If application rates change in the future, then this may need to be re

- evaluated.



## 7.0 Uncertainties Associated with Lack of Data or Acceptable Studies

7.1 Parent Sulfosulfuron Terrestrial plants appear to be very sensitive to sulfosulfuron exposure. While toxicity data were available for endpoints related to systemic growth, seedling emergence and visual injury, these guideline studies are not designed to capture reproductive endpoints. There is some evidence to suggest plant reproduction may be affected by sulfonylurea herbicides at levels below effects on vegetative growth or visual injury ( Asghari and Evans, 1992; 1993; Bhatti et. al., 1995; Boutin et. al. 2000; Fletcher, 1993, 1995, 1996) . Uncertainty regarding the potentially greater sensitivity of terrestrial plant reproduction has been discussed extensively in the environmental fate and effects assessment for chlorsulfuron (US EPA, 2005). Although there is no firm evidence for sulfosulfuron causing reproductive impairment, reproduc tive impairment cannot be discounted without data. Therefore, to the extent that terrestrial plant reproduction are more sensitive to sulfosulfuron than growth endpoints, risks to terrestrial plants may be underestimated if risks are based solely on growth endpoints. Additional information on the reproductive toxicity of sulfosulfuron to terrestrial plants would help address this uncertainty.

In addition, both of the registrant submitted vegetative vigor and seedling emergence tests were conducted using the technical grade active ingredient only and not a typical end

- use product (TEP). Current guidance (40 CFR Part 158.660) requires terrestrial plant toxicity testing to be conducted using a TEP as plants may be exposed to other components in a TEP as we ll as the active ingredient. Furthermore, as sulfosulfuron is a herbicide, there is concern and uncertainty in how the other ingredients in the TEP may influence or affect the toxicity to terrestrial plants. Therefore, additional Tier II vegetative vigor and seedling emergence toxicity studies using a TEP are requested. This additional data will be used to help refine the risk to terrestrial plants by evaluating toxicity from exposure to a sulfosulfuron typical end

- use product.

Acceptable acute avian or al toxicity data were not submitted for a passerine species exposed to sulfosulfuron. The available acute oral toxicity data for mallard ducks and bobwhite quails, when compared to estimated environmental concentrations, indicate that levels of concern ar e not exceeded for birds on an acute basis. Because passerine species have higher metabolic rates

### 30

due to their smaller sizes than either waterfowl or upland game bird species and because they may utilize different metabolic pathways, they may be more sens itive to sulfosulfuron. In addition, for the acute oral study with bobwhite quail, signs of toxicity were observed at the two highest test doses and an effect on body weight gain at the highest dose. Therefore, there were some effects on birds observed af ter acute oral exposure to sulfosulfuron. In order to characterize risk to passerines, an avian oral toxicity test is required for passerine birds. This additional data will be used to refine the screening

- level risk assessment by determining whether th ere are differences in avian species sensitivity to sulfosulfuron between passerine and currently tested upland game and/or waterfowl species that are beyond the simple allometric predictions currently employed in the absence of such passerine data. The cu rrent extrapolation method may be under

- or over

- estimating risks to passerines.

There is uncertainty in the available toxicity data for aquatic vascular and non

- vascular plants. For the aquatic vascular plant toxicity data (i.e., Lemna gibba ), none of t he test concentrations were analyzed; therefore, there is uncertainty in the actual exposure concentration. In addition, at the highest concentration tested, only 50% inhibition was observed therefore, the EC 50 

### value is an approximate value. For the repo rted most sensitive non

- vascular aquatic species, the green algae, the EC 50 

### and the NOAEC values fall within the range of test concentrations that were not analyzed. In addition, for the cyanobacteria species, Anabaena flos

aquae , particulate matter was o bserved, the EC 50 

### and EC 05 

### values fall within range of test concentrations that were not measured. Therefore, again, there is uncertainty in the actual exposure concentrations for these two non

- vascular studies. As the EC 50 

### value for cyanobacteria is cl ose to the EC 50 

### value for green algae, there is uncertainty in which species may be more sensitive to sulfosulfuron exposure. Due t o the fact that aquatic vascular and non

- vascular plant species are sensitive to sulfosulfuron exposure, and sulfosulfuron is applied in many different scenarios where drift or runoff is expected to enter aquatic ecosystem, there is uncertainty in whether the reported toxicity data are appropriate for evaluating risk.

If the registration review risk assessment, including listed species assessments, is performed without these data discussed above, the Agency would have to assume that sulfosulfuron “may affect” these taxa directly (and listed species from other taxa indir ectly), and use of sulfosulfuron and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Specie s Act and could result in restrictions for sulfosulfuron use that might prove to be unnecessar il y severe, therefore this data is requested to address this area of uncertainty.

Chronic toxicity data was not available for estuarine

- marine fish and inverteb rates, and given that sulfosulfuron is registered for use in turf areas (e.g., golf courses and hotel properties), application of sulfosulfuron may occur near estuarine

- marine ecosystems. Risk to these taxa from chronic exposure to sulfosulfuron were calc ulated using acute to chronic ratios using data from ECOSAR for the fish and invertebrates and from sulfonylurea chemical specific information for the invertebrates. For the chronic fish toxicity value, there is uncertainty in using this modeled data as i t was from the imidazole chemical class (an aromatic heterocyclic diazole (five

- membered ring consisting of three carbon atoms and two nitrogen atoms). While sulfosulfuron contains a five

- membered ring with two nitrogen atoms, it is attached to a six

### 31

memb ered ring, therefore, there is some uncertainty in whether the imidazole class is wholly appropriate. However, it was deemed to be sufficiently appropriate and therefore was used for evaluating chronic risk to estuarine

- marine fish. Based on the availabl e toxicity data, risk to estuarine

- marine fish and invertebrates is expected to be low and chronic toxicity data is not requested at this time. This is based on several lines of evidence. First, toxicity to freshwater fish and invertebrates from chronic exposure to sulfosulfuron is expected to be low based on the chronic toxicity data for these taxa and the estimated environmental concentrations, as the NOAEC values are at least 19,000 times greater than the EECs. Second, using data from other chemicals and/or the ECOSAR model to estimate chronic toxicity values for estuarine

- marine fish and invertebrates also show that these estimated toxicity values are at least 1000 times greater than the EECs. Finally, there is no additional evidence at this time that would indicate that estuarine

- marine fish and invertebrates are expected to be more sensitive to chronic sulfosulfuron exposure than freshwater fish and invertebrates. In the absence of this data, the chronic toxicity values for the freshwater fish and i nvertebrate may be used for estuarine

- marine animals.

In addition, toxicity data for sediment

- dwelling organisms is also not available. However, risk to these organisms is expected to be low. Although the fate data indicates that the half

- life of sulfos ulfuron in soil and the aquatic environment is expected to be greater than 10 days (40 CFR Part 158 trigger for chronic sediment testing), s ulfosulfuron is not expected to partition to the sediment but rather is expected to be mobile ( K oc 

### = 33.2 mL/g ; K ads 

### = 0.29 mL/g ) . In addition, sulfosulfuron is not expected to bioaccumulate as the Log Kow values range from

- 1.37 to 0.81. Therefore, sediment toxicity testing is not triggered under 40 CFR Part 158. Also, sulfosulfuron is classified as acutely practica lly non

- toxic to other aquatic animals and the chronic toxicity data also indicates low toxicity based on available data.



## 7.2 Degradate/Metabolites of Sulfosulfuron

Degradate or metabolite toxicity data were not available for any taxa. Several metabolites have been identified as residues of concern by HED ; sulfonamide metabolite, sulfonic acid, and sulfone (Section 3.1 ). Sulfosulfuron and the residues of concern (metabolites) were all considered and converted to the common ethyl sulfone moiety, 2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine. The sulfonamide ( 2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine

- 3

- sulfonamide) was identified as both a major degradate and a residue of concern for human health , and limited fate data is available for this residue. Therefore, this total toxic residue (TTR) approach is anticipate d to be undertaken by EFED when assessing exposure to non

- target aquatic animals

.
Although there are no degradate/metabolite toxicity data available, additional toxicity data for these residues is not requested at this time for terrestrial or aquatic a nimals. Sulfosulfuron is classified as practically non

- toxic on an acute basis for terrestrial and aquatic animals. The registrant submitted acute toxicity studies resulted in non

- definitive acute toxicity LD50/LC50/EC50 values and a comparison of these non

- definitive values for acute values or chronic NOAEC values to predicted exposure concentrations demonstrated that in these toxicity values were substantially greater than the EECs ( fish and invertebrates

– approximately 14 times on an acute basis and 2 0 times on chronic basis; birds

– at least 47 times on an acute basis and 8

### 32

times on a chronic basis; mammals approximately 380 times on an acute basis and at least 24 times on a chronic basis)

.
However, sulfosulfuron is observed to be quite toxic to terrestrial and aquatic plants. Therefore, there is uncertainty in whether the observed degradates may also cause adverse effects to terrestrial and aquatic plants. Therefore, the structure and their percent formation in environmental fate studies were e xamined. Degradates/metabolites/residues that retained all or part of the sulfonyl urea (SU) moiety and were formed at 10% or greater (potential major degradate) in one or more environmental fate studies were examined and are presented along with their pe rcent formation in various fate studies ( Table 7 ).

Non

- target organisms may be exposed to p arent sulfosulfuron and its degradates/metabolites throu gh spray drift and/or runoff. Environmental processes such as hydrolysis, photolysis and aerobic metabolism may facilitate the generation of sulfosulfuron degradates/metabolites that may then be present in runoff and/or in spray drift and expose non

- target areas such as adjacent fields and water systems. Based on the information in Table 7 , it appears that the processes of hydrolysis and aquatic photol ysis as well as aerobic soil metabolism generate the majority of the major degradates (>10%). Several degradates were observed in the anaerobic aquatic metabolism study; however, the degradates formed under this process are anticipated to be less environm entally relevant for the taxa of concern.

The calculated aqueous photolysis half

- life of parent sulfosulfuron is reported to be 2.5 days and several major degradates are formed. While photolysis of sulfosulfuron on leaf surfaces of terrestrial pl ants could be expected to occur, the rapid rate of absorption of the parent compound into the plant is anticipated to mitigate the formation of photolysis degradates.

The calculated aqueous photolysis half

- life of parent sulfosulfuron is reported to be 2.5 days

, Several major degradates were observed in the aqueous photolysis study . Formation of any degradates greater than 10% was not observed until at least the 24 hour sampling period.

In the aquatic environment, plants may be exposed to the photo

- degradates. Six degradates that formed at ≥ 10% were observed in laboratory aqueous photolysis studies with a range of formation from 10 to 28%. The first observance of the majority of the de gradates at ≥ 10% occurred between 24 and 72 hours during the 6 day study. Formation of several of these degradates were still increasing at the end of the study. For the degradate aminopyrimidine, formation of 10% was measured at 48 hours and increasing t o 28% by the end of the study. For sulfamic acid, formation was 13.8% at 48 hours and 21% at day 6; for oxamic acid formation of 11% was measured at 96 hours and increased to 15.6% at test termination. For sulfone, formation of 14.3% was measured at 24 ho urs and was 21% at test termination with a peak measurement of 28.3% at 96 hours. For the other two degradates formation greater than 10% occurred for either 48 or 72 hours and peaked during the duration of the test, (sulfonic acid 12.7% at 72 hours, 14.6 % at 96 hours and 13.3% at day 6; N

- hydroxy urea 13.3% at 24 hours, 15% at 48 hours and 11.3% at 72 hours). Therefore, with the possibility of exposure to these photodegradates, further investigation was warranted for aquatic plants.

### 33

An evaluation of th e potential toxicity of these degradates to aquatic plants was examined using the QSAR program ECOSAR. Green algae toxicity values can typically be obtained using ECOSAR. ECOSAR gave toxicity values for the classes of: anilines 13 

### , amides 14 

### , phenols 15 

### and

ne utral organics

– acid. It also listed imidazoles however, green algae toxicity values were not listed for this ECOSAR class. The 96

- hour EC 50 

### green algae toxicity values for the other groups ranged from 1.9 to 74 mg/L. The report also indicated that fo r the anilines, N

- substituted anilines are less toxic than predicted by these SARs, which would correspond to these degradates. Furthermore, in a study by Liping Wei et. al., 1998, three sulfonyl ureas and their main degradates were tested using green alg ae in 96 hour assays. The study reported that the parent sulfonyl ureas were more toxic than the degradates by about 2 to 3 orders of magnitude. Therefore, based on this paper and the ECOSAR data it appears that for non

- vascular plants the degradates may not be as toxic as parent sulfosulfuron.

However, as discussed above for parent sulfosulfuron there is uncertainty as to whether the chemical classes in ECOSAR are appropriate when trying to evaluate plant toxicity from sulfosulfuron degradates as these classes contain relatively basic chemical structures found in some of the degradates but do not fully represent the structure of the degradates. Moreover than the ECOSAR compat ibility , based on the Lemna study, aquatic vascular plants are more sensitive to sulfosulfuron than non

- vascular plants ( i.e. green algae). Therefore, there is uncertainty on whether the evaluation of green algae toxicity data is adequate to bridge to aqu atic vascular plants..

For three of the observed degradates in the aqueous photolysis study the percent formation was still increasing when the study was terminated ; aminopyyrimidine, sulfamic acid and oxamic acid; therefore it is unknown what the maximu m percentage formed under these conditions may have been. In addition, for sulfone, formation of greater than 10%, with a peak of 28%, was observed for five of the six days suggesting that this degradate may be persistent enough to be available for uptake by aquatic plants. T oxicity data for aquatic vascular plants ( Lemna ) is requested for these four degradates. If toxicity data are not available when the risk assessment is prepared, a total toxic residue (TTR) approach is anticipated to be undertaken fo r aquatic vascular plants. As the percent formation for the other two degradates, sulfonic acid and N

hydroxy urea, ranged from 11.3 to 14.6% for 48 or 72 hours and peaked during the assays, these degradates are not anticipated to impact the overall exposu re and toxicity to aquatic vascular plants; therefore toxicity data for these degradates are not requested at this time

For the de s methyl degradate, it is structurally very similar to parent sulfosulfuron. In the aerobic aquatic metabolism study, 14 an d 13% formation was observed at 30 days, with less than 10% observed at the 14 and 61 sampling periods. Given the time between sampling periods it is not known how long or at what percentage this degradate was present in the system. As this degradate is very similar to the parent, it may exhibit similar toxicity to aquatic vascular plants. As such, an aquatic vascular plant toxicity test for this degradates is requested

. A s stated above if this data is not available, then a TTR approach is expected to b e undertaken.

13 Anilines (aromatic amines)

– phenyl group attached to an amino group
14 Amides

– carbonyl group (R

- C=O) linked to a nitrogen group
15 Phenols

– phenol bonded to a hydroxyl group

### 34

The additional studies requested for each of the degradates is described in Section 16.0

.



## 8.0 Incident Database Review

A preliminary review was made on March 22, 2011 of the Ecological Incident Information System (EIIS, version 2.1), which is maintained by the Agency’s Office of Pesticide Programs, and the Avian Monitoring Information System (AIMS), which is maintained by the American Bird Conservancy . No incidents were found in the EIIS or AIMS database

.

In addition to possible incidents recorded in EIIS, additional incidents may be reported to the Agency in aggregated incident reports. Pesticide registrants report certain types of incidents to the Agency as aggregate counts of incidents occurring per product per quarter. Ecolo gical incidents reported in aggregate reports include those categorized as “minor fish and wildlife” (W

- B), “minor plant” (P

- B), and “other nontarget” (ONT) incidents. “Other nontarget” incidents include reports of adverse effects to insects and other ter restrial invertebrates. For sulfosulfuron

, no minor incidents were reported in the database (accessed March 22, 2011 ).

In the risk assessment, these databases will be checked again and any incidents reported will be further evaluated to determine if the reported incidents represent current patterns of use for sulfosulfuron . Examples of additional considerations are mitigation ( e.g ., reduced application rates), product cancellations, and changes in use patterns that have occurred since the date of the
rep orted incident(s).



## 9.0 Monitoring Data

The US Geological Survey (USGS), reports that sulfosulfuron has been detected in the drinking water facilities at four locations (see Table 10 ). The data show the percent of the total number of samples in which the herbicide was detected and the maximum concentration observed at that location.

### 35

Table 10

. Detection Frequency and Maximum Concentration of Sulfosulfuron at Four Drinking Water Facilities

Reservoir Location Concentration at Water

- supply Intake Concentration at Reservoir Outflow Site Concentration of

Treated Effluent

Detection % Max

Conc. (ppb) Detection

% Max

Conc. (ppb) Detection

% Max

Conc. (ppb) 

### Indianapolis Water Co., IN - - - - 5 0.04



### Higginsville Reservoir, MO 11 0.018 10 0.026

- -



### East Fork Lake, OH 47 0.05 36 0.021

- - 

### Lake Mitchell, SD 5 0.021 11 0.023 9 0.026
Source: USGS Open file report 01

- 456 (Pesticides in Selected Water

- Supply Reservoirs and Finished Drinking Water, 1999

- 2000: Summary of results from a Pilot Monitoring Program)



### The National Water

- Quality Assessment (NAWQA) Program database was searched (July 2010) fo r the latest surface and groundwater monitoring results for sulfosulfuron. Sulfosulfuron has been monitored for in 42 states where there have been 82 samples where the herbicide has been found to be above detection limits. In these incidences the concent rations have ranged from 0.010 to 0.870 ppb. There is no sulfosulfuron water concentration data listed in the USEPA STORET database.



## 10.0 Clean Water Act

Sulfosulfuron is not identified as a cause of impairment for any water bodies listed as impaired under se ction 303(d) of the Clean Water Act, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause _group_id=88 5 . In addition, no Total Maximum Daily Loads (TMDL) has been developed for sulfosulfuron

, based on information provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES . More information on impaired water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/

.
The Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP ’ s Registration Review Risk Assessment and Management Process (see: http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1

- sop.pdf), in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

### 36



## 11.0 Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope; therefore, it may not be possible to identify specific ecosystems during the development of a n ation

- wide ecological risk assessment. However, in general terms, terrestrial ecosystems potentially at risk could include the treated field and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the treated field could includ e cultivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats and other uncultivated areas.

Aquatic ecosystems potentially at risk include water bodies adjacent to or down stream from the treated field and could include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also includes marine ecosystems, including estuaries.



## 12.0 Assessment Endpoints

Assessment e ndpoints are defined as “explicit expressions of the actual environmental value that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the environment that are considered to be at risk; and 2) operationally defining the assessment endpoint in terms of an ecological entity ( i.e ., a community of fish and aquatic invertebrates) and its attributes ( i.e ., survival and reproduction). Therefore, selection of the assessment endpoints is based on value d entities ( i.e ., ecological receptors), the ecosystems potentially at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide

- related contamination. The selection of clearly defined assessment endpoints is impor tant because they provide direction and boundaries in the risk assessment for addressing risk management issues of concern. Changes to assessment endpoints are typically estimated from the available toxicity studies, which are used as the measures of effe cts to characterize potential ecological risks associated with exposure to a pesticide, such as sulfosulfuron

.
To estimate exposure concentrations, the ecological risk assessment considers applications at maximum rates. If multiple applications are allowed, the maximum amount per application and minimum interval between applications are used

– provided that maximum total annual application amounts are also included in this configuration. Several EFED exposure models ( e.g ., PRZM

- EXAMS, T

- REX) are use d to estimate likely high

- end exposure to sulfosulfuron

. The most sensitive toxicity endpoints are used from surrogate test species to estimate treatment

related direct effects on acute mortality and chronic reproductive, growth and survival assessment end points. Toxicity tests are intended to determine effects of pesticide exposure on birds, mammals, fish, terrestrial and aquatic invertebrates, and plants. These tests include short

term acute, sub

- acute, and reproduction studies and are typically arrange d in a hierarchical or tiered system that progresses from basic laboratory tests to applied field studies. The toxicity studies are used to evaluate the potential of a pesticide to cause adverse effects, to determine whether further testing is required, a nd to determine the need for precautionary label statements to minimize the potential adverse effects to non

- target animals and plants.

### 37



## 13.0 Conceptual Model

The conceptual model depicts the potential pathways for ecological risk associated with sulfosulfur on use. The conceptual model provides an overview of the expected exposure routes for terrestrial and aquatic organisms.

The potential exposure pathways and effects of sulfosulfuron on terrestrial environments are depicted in Figure 3 and for aquatic environments in Figure 4

. Figure 5 depicts exposure from drinking water and inhalation to terrestrial vertebrates and invertebrates. Solid arrows depict the most likely routes of exposure and effects; dashed lines depict potential routes of exposure that are not considered likely for sulfosulfuron

.

### Figure 3

. Conceptual Model Depicting Potential Risks to Terrestrial Animals and Plants from the Use of Sulfosulfuron

### 39

Figure 4

. Conceptual Model Depicting Potential Risks to Aquatic Animals and Plants from the Use of Sulfosulfuron

### 40

Figure 5

. Conceptual Mod el Depicting Potential Risks to Terrestrial Vertebrates and Inverteb rates from Inhalation and Drinking Water Exposure from the Use of Sulfosulfuron

## 14.0 Risk Hypothesis

Based on an examination of the physical/chemical properties of sulfosulfuron , its fate and disposition in the environment, and its mode of application, a conc eptual model was developed that represents the possible relationships between this pesticide as a stressor, ecological receptors, and the assessment endpoints.

Although transport of the compound through runoff and/or erosion is likely to be limited by low application rates, sulfosulfuron is mobile and is expected to be transported to surface and groundwater by run

- off or leaching. Laboratory and field studies in dicate that sulfosulfuron will persist for sufficient periods (days to weeks) to be available for transport off

- site.

Figure 3 indicates that the greatest potential exposure to aquatic plants and animals is most likely through spray drift and runoff. Depending on the extent of spray drift contamination, plants in aq uatic environments will likely be affected. Because sulfosulfuron is classified as practically nontoxic to aquatic animals on an acute basis and rate of application is very low, minimal adverse effects are anticipated to aquatic animals ; based on current application rates and available data, the acute toxicity values are at least 10,000 times greater than the parent sulfosulfuron EECs

. C hronic adverse effects are not anticipated for aquatic animals because the low application rates are not likely to resul t in sufficient exposure to be a concern to aquatic animals . Based on the lowest chronic NOAEC value for fish and invertebrates identified above, 8.78 and 5.73 mg a.i./L, respectively, and the 60

- day and 21

- day EEC values of 4.6 and 5.2 μg a.i./L, respect ively, the chronic toxicity values are at least 1000 times greater than the parent sulfosulfuron EEC values. Due to the low application rates and low chronic toxicity endpoints,

c hronic effects to freshwater fish and aquatic invertebrates are not expected to occur from exposure to sulfosulfuron

.
Figure 4 indicates that the greatest potential exposure to terrestrial plants and animals is most likely through direct application, spray drift and runoff. Sulfosulfuron is practically non

- toxic to birds and mammals on an acute exposure basis , and the application rates are relatively low . As a result, direct acute risk to terrestrial animals has not exceeded conce rn levels in previous assessments. Based on the available data, chronic risk to birds and mammals potentially is expected to be minimal, except potentially from drinking water (see discussion below). Using the toxicity data identified in Section 5.1.2 and 5.1.4 and the calculated TREX EECs, the toxicity values are at least 8 times greater than the EECs. However, data in passerine species are being requested to address data gaps in the acute avian database. Therefore, no definitive risk conclusions can be made with respect to birds until those data are submitted. A comparis on between the non

- definitive acute contact honeybee study and the EEC indicate that the toxicity value is at least 11.5 times greater than the EEC. While no formalized process for evaluating potential for risk from oral exposure currently exists, if no f ormal approach exists when conducting the risk assessment, the approached discussed in Section 6.0 will be used.

In addition, exposure to piscivorous birds and mam mals via the food chain is another potential exposure route to animals. However, given that sulfosulfuron is not expected to

### 42

bioaccumulate based on the Log Kow of

- 1.37 to 0.81, risk to these animals from this exposure route is not expected, and therefore , this exposure route is not reflected in Figure 4

.
Exposure through drinking water is another potential exposure route and is presented in Figure 5

. The S creening I mbibition P rogram (SIP v.1.0, Released June 15, 2010) was used to calculate an upper bound estimate of exposure using Sulfosulfuron ’s solubility ( 1627 ppm , pH 7 ), the most sensitive acute and chronic avian toxicity endpoints (Bobwhite Quail with LD 50 

### > 2250 mg/kg

- bw and mallard duck NOAEC = 250 ppm, respectively) and the most sensitive acute and chronic mammalian toxicity endpoints (Rat LD 50 

### >5000 mg/kg

- bw and NOAEL = 3 12 mg/kg

- bw, respectively). Based on the output, exposure through drinking water alone is potential acute and chronic risk to small birds and a potential chronic risk to small mammals. Although, due to the use of the non

- definitive acute values where no mortality was observed at those reported levels, the potential for acute risk is expected to be quite conservative. The output generated by SIP v.1.0 is presented in Appendix F

.
Inhalation is another potential exposure route for terrestrial vertebrates. Based on the vapor pressure of sulfosulfuron, volatilization is not expected, and therefore risk from inhalation is not expected. The 4

- hr LC 50 

### inhalation study usi ng rats was a non

- definitive value in that no mortality was observed at 3.0 mg/L (MRID 44295745). The STIR model (Screening Tool for Inhalation Risk) was used to evaluate inhalation risk to birds. The non

- definitive acute oral values for both birds and m ammals were used in the model. Based on STIR , risk to birds from inhalation alone is not expected. The STIR input and output are presented in Appendix G

.

Based o n the available toxicity data, sulfosulfuron appears to be very toxic to plants. When used in accordance with the label, sulfosulfuron may move off

- site of application by spray drift and/or runoff. This may result in potential risk to the survival, growt h, and reproduction of terrestrial non

- target plants inhabiting adjacent or nearby acreage to the site of application. Sulfosulfuron is expected to move to surface waters adjacent to application sites by spray drift and/or runoff where it may affect both vascular and nonvascular aquatic plants.

Since sulfosulfuron is very phytotoxic to plants and has the potential to leach into ground water, irrigation from shallow ground water aquifers may adversely impact non

- target sensitive crops. In addition, s urface waters contaminated with runoff or spray drift residues of sulfosulfuron when used to irrigate non

- target crops may adversely impact non

- target sensitive
crops.

Because adverse effects to non

- target terrestrial and aquatic plants can be expected, t errestrial and aquatic animals may be indirectly affected through the reductions in primary productivity and habitat.

Based on the above information, the following risk hypothesis is used for sulfosulfuron:

Based on the application methods, mode of action, persistence and mobility of sulfosulfuron , direct deleterious effects to non

- target terrestrial and aquatic plant communities and indirect effects to both aquatic and terrestrial species through habitat

### 43

mod ification are likely. Direct acute and chronic toxic effects to animals are e xpected to be limited, although without submission of additional avian information there is uncertainty in risk conclusions.



## 15.0 Analysis Plan

In registration review, pesticide ec ological risk assessments will follow the Agency’s Guidelines for Ecological Risk Assessment, will be in compliance with the paper titled “Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency” (“Overview Document”) (January 2004), and will be done in accordance with Section 7 of the Endangered Species Act (US EPA, 2004)

.

P reviously completed screening level risk assessments and exceedances of Agency levels of concern indicate a need to further examine and refine phytotoxic risk to aquatic and terrestrial plant species. Analysis of potential indirect effects on listed species (both aquatic and terrestrial) is also required. This analysis plan will be revisited and may be revised depend ing upon the data available in the open literature and the information submitted by the public in response to the opening of the Registration Review docket.



## 15.1 Ecological Measures of Exposure

In order to assess risk to terrestrial birds and mammals

, t he model used to predict terrestrial EECs on food items is Terrestrial Residue Exposure (T

- REX) model. The model used to derive EECs relevant to terrestrial and wetland plants is TerrPlant. This model uses estimates of pesticides in runoff and in spray drif t to calculate EECs. EECs are based upon solubility, application rate and minimum incorporation depth. The spray drift model, AgDRIFT is used to assess exposures of sulfosulfuron deposited on terrestrial habitats by spray drift. These models are paramet erized using relevant reviewed registrant

- submitted environmental fate data.

Use information will be retrieved from registration labels and used as inputs for estimating exposure concentrations from the various use scenarios. Sulfosulfuron ’s use patterns (aerial application) suggest potential risk concerns to non

- target aquatic and terrestrial plants. The range of potential exposure to sulfosulfuron to non

- target plants can vary on application method (aerial or ground), application rate, and use pattern

.
Specific environmental fate related activities necessary to complete an aquatic e cological r isk

a ssessment of sulfosulfuron may include the following:

Environmental concentrations will be modeled using PRZM

- EXAMS

. When t here are multiple crop use scenarios for sulfosulfuron mode ling using PRZM

- EXAMS, and EFED will choose conservative surrogate scenarios that are likely to generate high

- end EECs. In addition, the potential for contaminated irrigation water to adversely af

fect sensitive agricultural crops will be assessed.

As metabolites and a degradate were identified as residues of concern, aquatic EECs will be modeled using the total toxic residue approach.

### 44

Exposure from drinking water pathway will be explored furth er with the development of SIP v.2.0 in the Ecological Risk Assessment for sulfosulfuron. Detailed information about the SIP v.1.0, as well as the tool, can be found on the EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial

.

Non

- target crops may be exposed to contaminated i rrigation waters from surface water or shallow ground water containing sulfosulfuron . The potential risks to plants when exposed to irrigation water contaminated with sulfosulfuron will be estimated for both ground water and surface water irrigation sources. The EEC for ground water will be calculated using the T ier 1 SCIGROW model while that for surface water will be calculated using PRZM/EXAMS from the scenario yielding the highest EECs. Comparisons will be made to the most sensitive endpoint from vegetative vigor study assuming that runoff of irrigation water does not occur.



## 15.2 Drinking Water Measures of Exposure

The Environmental Fate and Effects Division (EFED) was requested to prepare a human health drinking water risk assessments for the propose d new use of sulfosulfuron on grass forage, fodder, and hay (C rop Group 17) which includes Bermuda and Bahia grass pastures. Estimated drinking water concentrations (EDWCs) for surface and ground water were derived from the EFED Tier 1 screening models, FIRST and SCI

- GROW, respectively. This document presented a Tier 1 drinking water assessment (DWA) which was prepared for the Health Effects Division (HED) as part of Human Risk Assessment and Tolerance Petition for the proposed new use of sulfosulfuron ( DP Barcode: D327364, May 24, 2007) . Previous drinking water asses sments (D304290, D304476, D304659) have resulted in estimated drinking water concentrations (EDWCs) which were below the HED level of concern (LOC). A summary of the environmental fate data for sulfosulfuron which were used in the previous drinking water a ssessments are presented in Table 6

.

Both the parent and sulfonamide moiety degradation products are being considered for the Registration Review drinking water ass essment as well as for ecological risk assessment. Calculated Residues of Concern (ROC) chemical properties for this assessment are also presented in Table 6

.



## 15.3 Measu res of Effect

The acute measures of effect use d for animals in this screening

- level assessment are the LD 50 

### , LC 50 

### and EC 50 

### . LD stands for "Lethal Dose", and LD 50 

### is the amount of a material, given all at once, that is estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” and LC 50 

### is the concentration of a chemical that is estimated to kill 50% of the test organisms. EC s tands for “Effective Concentration” and the EC 50 

### is the concentration of a chemical that is estimated to produce a specific effect in 50% of the test organisms.

### 45

Endpoints for chronic measures of exposure for listed and non

- listed animals are the NOAEL/NOA EC and NOEC. NOAEL stands for “No Observed

- Adverse

- Effect

- Level” and refers to the highest tested dose of a substance that has been reported to have no harmful (adverse) effects on test organisms. The NOAEC ( i.e. , “No

- Observed

- Adverse

- Effect

Concentratio n”) is the highest test concentration at which none of the observed effects were statistically different from the control. The NOEC is the No

- Observed

- Effects

- Concentration. For non

- listed plants, only acute exposures are assessed ( i.e. , EC 25 

### for terrest rial plants and EC 50 

### for aquatic plants); for listed plants, either the NOAEC or EC 05 

### is used.



## 15.4 Uncertainties in the Analysis Plan

Due to fate characteristics, use patterns, and the lack of data there are uncertainties with risk potential to; 1) passeri ne birds, 2) growth, survival and reproductive effects to terrestrial plants, 3) vascular and non

- vascular aquatic plants. Available toxicity data indicate that sulfosulfuron is practically non

- toxic to avian species on an acute oral basis, and passerine species may be more or less sensitive to sulfosulfuron than waterfowl or upland game birds. In the absence of data on passerine species, risk will be presumed to exceed concern levels. Given the uncertainties in the terrestrial and aquatic plant toxicity data, the current toxicity values may be und erestimating toxicity to these taxa; therefore, direct risk to plants and potential indirect effects as well as the overall effect area may be underestimated.



## 15.5 Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally

- listed threatened and/or endangered (listed) species from registered uses of sulfosulfuron . This assessment will be conducted i n accordance wit h the Overview Document (USEPA, 2004), provisions of the ESA, and the Services’ Endangered Species Consultation Handbook (USFWS/NMFS, 1998).

The action area is used to identify all listed (threatened and endangered) species and designated critical habitat that could be affected by the Federal action. The Federal action is the authorization or registration of pesticide use or uses as described on the label(s) of pesticide products containing a particular active ingredient. The action area is defined by th e Endangered Species Act as, “all areas to be affected directly or indirectly by the Federal action and not merely the immediate are involved in the action” (50 CFR §402.2). Based on an analysis of the Federal action, the action area is defined by the act ual and potential use of the pesticide.

In the case of nationwide ecological risk assessment conducted for sulfosulfuron under Registration Review, the action area will encompass the entire U nited S tates and its territories. The purpose of defining the action area as the entire U nited S tates and its territories is to ensure that the initial area of consideration encompasses all areas where sulfosulfuron may be used now and in the future, including the po tential for off

- site transport via spray drift and downstream dilution. Additionally, the concept of a nationwide action area takes into account the potential for direct and indirect effects and any potential modification to critical habitat based on

### 46

ecol ogical effect measures associated with reduction in survival, growth, and reproduction, as well as the full suite of sublethal effects available in the effects literature. It is important to note that the nationwide action area does not imply that direct and/or indirect effects and critical habitat modification are expected to or are likely to occur over the full extent of the action area, but rather to identify all listed species and critical habitat that may potentially be affected by the action. The Ag ency will use more rigorous analysis including consideration of available land cover data, toxicity data, and exposure information to determine areas where individual listed species and designated critical habitat may be affected or modified via endpoints associated with reduced survival, growth, or reproduction.



## 16.0 Anticipated Data Needs

The Agency does foresee requiring additional fate and ecological effects studies prior to conducting the planned assessments. Table 11 to Table 13 presents the ecological effects studies currently available as we ll as any potential data gaps. Data gaps, uncertainties and potential paths forward for the assessment of sulfosulfuron are described below.

Table 11 . Available Ecological Effects Data for Terrestrial Animals Exposed to Sulfosulfu ron and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.2100 Avian oral toxicity 44295768 Acceptable Partial* * There is no passerine species data available, passerine species may be more sensitive to sulfosulfuron than either waterfowl or upland game species. 44295769 Acceptable

850.2200 Avian dietary

toxicity 44295770 Acceptable No

44295771 Acceptable

850.2300 Avian reproduction 44295772 Acceptable No 44295773 Acceptable

850.3020 Honeybee acute

contact toxicity 44295788 Acceptable No



### Table 12 . Available Ecological Effects Data for Aquatic Animals Exposed to Sulfosulfuron and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.1075 Freshwater fish

– acute

toxicit y 44295774

44295775 Acceptable

Acceptable No *Although data is not currently available, based on a screening level analysis, this data is not being requested at this time. 850.1400 Freshwater fish

–

early life stage test 44295779 Acceptable No

850.1010 Freshwater invertebrates

–

Acute toxicity 44295776 Acceptable No

### 47

Guideline Description MRID Classification Data Gap? Comments

850.1300 Freshwater invertebrate

–

life cycle test 44295780 Acceptable No

850.1075 Saltwater fish

–

Acute toxicity 44309304 Acceptable No

850.1025 850.1035 850.1045 850.1055 Saltwater invertebrates

–

Acute toxicity 44295777 Supplemental
No
44295778 Acceptable

850.1400 Saltwater fish

–

early life stage test No Data Submitted -- No*

850.1350 Saltwater invertebrates

–

life cycle test No Data

Submitted -- No*



### Table 13 . Available Ecological Effects Data for Plants Exposed to Sulfosulfuron and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? Comments

850.4225 Terrestrial Plant toxicity:

seedling emergence (Tier 2) 44295783 Supplemental Yes* * Seedling emergence and vegetative vigor study was conducted using TGAI, therefore, Tier II tests are requested using a TEP.

**For the green algae study, the EC50 and NOAEC values fall within concentrations not analyzed due because they were <LOQ. For cyanobacteria, precipitate was observed without removal prior to analysis and the EC50 and EC05 values fall within concentrations not analyzed due to <LOD.

***All concen trations were based on nominal because they were below the LOQ.

- Data is also needed to evaluate risk from exposure to the major degradates to aquatic non

- target vascular plant species. 850.4250 Terrestrial Plant toxicity:

vegetative vigor (Tier 2) 44295784 Supplemental Yes*

850.5400 Aquatic Plant Growth:

algae (Tiers 1 and 2) 44295781

44295782 44295785 44295786 Supplemental

Supplemental Supplemental Supplemental Partial**

850.4400 Aquatic Plant Growth:

vascular plants (Tier 2) 44295782 Supplemental Yes***

### 48

Table 14

. Degradates and Requested Studies Degradate Common Name ( C AS #, if available) Study

requested Comment

Sulfamic acid 850.4400

Aquatic plant (duckweed, Lemna ) These degradates form

via photolysis in aquatic environments (parent degradation half

- life of approx 2.5 days) or via aerobic aquatic metabolism

. An aquatic vascular plant study is needed to determine whether these degradates present a risk. Sulfone Oxamic acid

Aminopyrimidine

Desmethyl sulfosulfuron



## 16.1 Environmental Fate 835.6100 (Environmental Chemistry Method and Independent Laboratory Validation Only) for soil methods 835.6200 (Environmental Chemistry Method and Independent Laboratory Validation Only) for water methods



## 16.2 Ecological Effects

Several toxicity studies are needed to better assess the potential risk of sulfosulfuron exposure to non

- target organisms. The studies listed below should be submitted to increase certainty in the risk estimation.

850.2100, Acute Avian Oral Toxicity Test (with a Passerine species ). A protocol for Agency review is requested prior to conducting study; 850.4225, Nontarget Area Phytotoxicity Tier II, Seedling Emergence (tested using a Typical End

- use Product); 850.4250 , Nontarget Area Phytotoxicity Tier II, Vegetative Vigor (tested using a Typical End

- use Product); 850.4400, Nontarget Area Phytotoxicity Tier II, Aquatic Plant Growth (Vascular Plants), using Lemna spp., (using TGAI); 850.5400, Nontarget Area Phytotoxicit y Tier II, Aquatic plant Growth (Algal Plants) (with a green algal, Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum ) and a cyanobacteria, Ananabaena flos

- aquae );

### 49

Guideline Number: none, Special Non

- Target Plant Reproductive T oxicity Study to determine the EC 25 

### and NOAEC . A protocol for Agency review is requested prior to conducting study. 850.4400, Nontarget Area Phytotoxicity Tier I/II, Aquatic Plant Growth (Vascular Plants), using Lemna spp., (using degradates listed in T able 14 );

If the registration review risk assessment, including listed species assessments, is performed without these data, the Agency would have to assume that sulfosulfuron “may affect” these taxa directly (and listed species from other taxa indirectly), and use of sulfosulfuron and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and regist rants have in complying with the Endangered Species Act and could result in restrictions for sulfosulfuron use that might prove to be unnecessary given data to address this area of uncertainty.

The Agency will conduct a search of the open literature to en sure that all best available science is utilized. The Agency uses the ECOTOX database as its mechanism for searching the open literature for ecological effects information. ECOTOX integrates three previously independent databases

- AQUIRE, PHYTOTOX, and TERRETOX

- into a system which includes toxicity data derived predominately from the peer

- reviewed literature, for aquatic life, terrestrial plants, and terrestrial wildlife, respectively.



## 17.0 Other Information Needs

There is specific information that will a ssist the Agency in refining the ecological risk assessment, including any species

- specific effects determinations. The Agency is very much interested in obtaining the following information: 1. confirmation on the following label information

a. frequency of app lication, application intervals, and maximum number of applications per season b. geographic limitations on use 2. use or potential use distribution (e.g., acreage and geographical distribution of relevant crops) 3. use history 4. median and 90 th 

### percentile reported u se rates (lbs. a.i./acre) from usage data

– national, state, and county 5. application timing (date of first application and application intervals) by crop

– national, state, and county 6. sub

- county crop location data 7. usage/use information for non

- agricultural uses (e.g., forestry, residential, rights

- of

- way) 8. directly acquired county

- level usage data (not derived from state level data)

a. maximum reported use rate (lbs. a.i./acre) from usage data

– county b. percent crop treated

– county

c. median and 90 th 

### percentile num ber of applications

– county d. total pounds per year

– county

e. the year the pesticide was last used in the county/sub

- county area

### 50 f. the years in which the pesticide was applied in the county/sub

- county area 9. typical interval (days) 10. state or local use restrictions 11. ecological incidents (non

- target plant damage and avian, fish, reptilian, amphibian and mammalian mortalities) not already reported to the Agency 12. monitoring data

The analysis plan will be revisited and may be revised depending upon the data available in the open literature and the information submitted by the public in response to the opening of the Registration review docket.



## 18.0 Data Call

- In Tables For Fate and Ecological Effect Studies

18.1 Environmental Fate Studies

Guideline Number: 835.6100 (Environmental Chemistry Method and Independent Laboratory Validation Only) Study Title: Environmental Chemistry Method for Residues in Soil (and associated Independent Laboratory Validation) Rationale for Requiring the Data Independently validated analytical methods for residues in soil, water, sediment, and plant material (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological effects studies. Submitted

an alytical methods are also used by various federal, state, tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory validatio ns for submitted analytical methods are necessary to confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

- prepared validations.

Use of sulfosulfuron may impact terrestrial environments due to residues of concern during the application process. This is especially true for poorly draining soils, erodible soils, and soils with shallow ground water. Therefore, outside agencies may request analytical methods with
which to monitor for sulfosulfu ron residues of concern in soils.

An independently validated environmental chemistry method for sulfosulfuron residues in soils has not been submitted by the registrant. If aerobic soil metabolism data indicate that
sulfosulfuron is not transient in soils, a validated analytic method for residues in soil should be available. Therefore, a validated environmental chemistry method for sulfosulfuron in soil and an independent laboratory validation of the method are required to support monitoring for
sulf osulfuron residues and to evaluate newly submitted environmental fate and ecological
effects data. Practical Utility of the Data

### 51

How will the data be used? In the absence of independently validated environmental chemistry methods, submitted
environmental fate and ecological effects data may not be reviewable and entities outside the Agency may lack chemical

- specific methods for analyses in environmental compartments. Independently validated environmental chemistry methods will be used to evaluate newly

s ubmitted environmental fate and ecological effects data and will be made available for enforcement and monitoring purposes at the federal, state, and local levels.

How could the data change the Agency’s decision, or impact the Agency’s future decision

mak ing? Risk assessment conclusions could be altered if they are not supported by either study data or environmental monitoring detections that are based on independently validated environmental chemistry methods. Furthermore, while not directly related to Agency decision

- making, independently validated environmental chemistry methods are necessary to ensure the safety of those in proximity to releases of sulfosulfuron residues in the environment.

Guideline Number: 835.6200 (Environmental Chemistry Method and Independent Laboratory Validation Only) Study Title: Environmental Chemistry Method for Residues in Water (and associated Independent Laboratory Validation) Rationale for Requiring the Data Independently validated analytical methods for residues in soil, water, sediment, and plant material (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological effects studies. A report containing this data has b een submitted by the registrant; however, it has not been formally reviewed. In the interim the data has been accepted on a provisional basis but will still be identified as a data gap until the review is completed. Submitted analytical methods are also used by various federal, state, tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory validations for submitted analytica l methods are necessary to confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

- prepared validations.

Use of sulfosulfuron may impact surface water quality due to residues of concern in run off of rain water and drift of residues. This is especially true for poorly draining soils, erodible soils, and soils with shallow ground water. Therefore, outside agencies may request analytical
methods with which to monitor for sulfosulfuron residues o f concern in water.

An independently validated environmental chemistry method for sulfosulfuron residues in water has not been submitted by the registrant. If aerobic aquatic metabolism data indicate that sulfosulfuron is not transient in acidic, aerobic water bodies, a validated analytic method for residues in water should be available. Therefore, a validated environmental chemistry method for sulfosulfuron in water and an independent laboratory validation of the method are required

### 52

to support monitorin g for sulfosulfuron residues and to evaluate newly submitted environmental fate and ecological effects data.

Practical Utility of the Data
How will the data be used? In the absence of independently validated environmental chemistry methods, submitted environmental fate and ecological effects data may not be reviewable and entities outside the Agency may lack chemical

- specific methods for analyses in environmental compartments. Independently validated environmental chemistry methods will be used to eva luate newly submitted environmental fate and ecological effects data and will be made available for enforcement and monitoring purposes at the federal, state, and local levels.

How could the data change the Agency’s decision, or impact the Agency’s future decision

making? Risk assessment conclusions could be altered if they are not supported by either study data or environmental monitoring detections that are based on independently validated environmental chemistry methods. Furthermore, while not direct ly related to Agency decision

- making, independently validated environmental chemistry methods are necessary to ensure the safety of those in proximity to releases of sulfosulfuron residues in the environment.



## 18.2 Ecological Effects Studies

Guideline Number: 850.2100 Study Title: Avian Acute Oral Toxicity Test Test Substance: TGAI Rationale for Requiring the Data Acceptable acute avian oral toxicity data were not submitted for a passerine species exposed to sulfosulfuron , which is now required under the 40 CFR Part 158 (CFR 40 2008) data requirements for conventional pesticides. The revised Part 158 data requirements specify that acute avian oral toxicity data be submitted for either one waterf owl or one upland game speci es and one passerine species. Although available acute oral toxicity data for mallard ducks and bobwhite quails, when compared to estimated environmental concentrations, indicate that levels of concern are not exceeded for birds on an acute basis, however, in the acute oral study with bobwhite quail signs of toxicity were observed at the two highest test doses and an effect on body weight gain at the highest dose. Because passerine species have higher metabolic rates due to thei r smaller sizes than either waterfowl or upland game bird species

### 53

and because they may utilize different metabolic pathways, they may be more sensitive to sulfosulfuron . In order to properly characterize risk to passerines, an avian oral toxicity test is required for passerine birds. A passerine study protocol must be submitted for review by the Agency prior to initiation of the study. Practical Utility of the Data How will the data be used? Acute avian oral toxicity data for passerine species will be used to refine the screening

- level risk assessment by determining whether there are differences in avian species sensitivity to sulfosulfuron between currently tested passerine and upland game an d/or waterfowl species that are beyond the simple allometric predictions currently employed in the absence of such passerine data. The current extrapolation method may be under

- or over

- estimating risks to passerines. How could the data impact the Agency’s future decision

- making? If future risk assessments, including listed species assessments, are performed without these data, the Agency would have to assume that sulfosulfuron “may affect” listed birds directly (and listed species from other taxa indirectl y), and use of sulfosulfuron and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Ac t and could result in restrictions for sulfosulfuron use that might prove to be unnecessary given data to address this area of uncertainty.

### 54

Guideline Number: 850. 4225 and 850. 4250 Test Substance: Sulfosulfuron Typical End

- use Product (TEP) Study Title: Non

- target Area Phytotoxicity (Tier II) Seedling Emergence and Vegetative Vigor Test Species: Corn, soybeans, and a root crop, plus seven other species (six species of at least four families of dicots and four species of at least two families of monocots) Rationale for Requiring the Data Seedling emergence and vegetative vigor toxicity test with technical grade sulfosulfuron were submitted. Current guidance (40CFR Part 158) requires a Tier II terrestrial plant toxicity testing to be conducted using a TEP as plants are likely to be exposed to other components in a TEP as well as the active ingredient. Furthermore, as sulfosulfuron is a herbicide, there is concern and uncertainty in how the other ingredients in the TEP may influence or affect the toxicity to terrestrial plants. The current toxicity values for seedling emergence and vegetative vigor, when compared to the estimated environmental concentrations, indicate that the level of concern for terrestrial plants is exceeded.
Pract ical Utility of the Data How will the data be used? Data from Tier II seedling emergence and vegetative vigor toxicity studies using a TEP will be used to quantitatively estimate potential risks to terrestrial plants associated with the use of sulfosulfuron. These data will be used to define an action area for endangered species and explore risk mitigation strategies. The data will reduce uncertainties associated with the risk assessment for terrestrial plants and will improve the Agency ’ s unde rstanding of the potential effects of sulfosulfuron on terrestrial plants. How could the data impact the Agency ’ s future decision

- making? The value of these seedling emergence and vegetative vigor studies would be in quantifying and potentially refining risks to non

- target terrestrial plants. Primary producers (i.e. plants) provide oxygen, food and habitat vital to ecological processes. Therefore, a solid understanding of the potential risks to plants is essential in order to assess the environmental ris ks the use of sulfosulfuron may pose. D efining an action area for endangered species and exploring risk mitigation strategies may be underestimated without these data. Without TEP terrestrial plant toxicity data for sulfosulfuron, the Agency may underest imate the direct adverse effects to terrestrial plants and indirect effects (e.g., via loss of habitat/cover, riparian vegetation effects, etc.) . The lack of these data could limit the knowledge and flexibility the Agency and registrants have in coming in to compliance with the Endangered Species Act and could result in underestimating mitigation for sulfosulfuron.

### 55

Guideline Number: 850.4400 Test Substance: TGAI Study Title: Aquatic Plant Growth Toxicity Study using Lemna spp. Rationale for Requiring the Data A study using Lemna sp., was submitted by the registrant. However, none of the concentrations were analyzed during the study due to the concentration being lower than the reported limit of detection; therefore, there is uncertainty in the actual exposure concentrations. In addition, at the highest concentration tested, only 50% inhibition was observed, therefore, the EC 50 

### value is an approximate value. Based on this approximate EC 50 

### value when compared to estimated environmental conce ntrations the level of concern is exceeded for aquatic vascular plants. Practical Utility of the Data How will the data be used? The data will be used to estimate potential risks to non

- target aquatic plants, including the likelihood of potential risks to endangered species, either by direct effects or by indirect effects, and to reduce uncertainties associated with the current ecol ogical risk assessment. By refining the assessment, the Agency will be able to determine whether current labeling is appropriate and whether further mitigation is necessary.

How could the data impact the Agency ’ s future decision

- making? The value of these data would be in quantifying and potentially refining risks to non

- target aquatic plants. These data, once submitted, will allow the Agency to further characterize the risk of sulfosulfuron to aquatic ecosystems. Primary producers (i.e. plants) pro vide oxygen, food and habitat vital to ecological processes. Therefore, a solid understanding of the potential risks to plants is essential in order to assess the environmental risks the use of sulfosulfuron may pose. D efining an action area for endanger ed species and exploring risk mitigation strategies may be underestimated without these data. The lack of these data could limit the knowledge and flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and co uld result in underestimating mitigation for sulfosulfuron.

Guideline Number: 850.5400, 122

- 2 Study Title: Aquatic Plant

- Marine Green Algae Pseudokirchneriella subcapitata (formerly known as Selenastrum capricornutum )

Guideline Number 850.5400, 122

- 2 Study Title: Aquatic Plant

- Cyanobacteria Anabaena flos

- aquae Test Substance: TGAI (both studies) Rationale for Requiring the Data

For the reported most sensitive non

- vascular aquatic species, the green algae, the EC 50 

### and the NOAEC values fall within the range of test concentrations that were not analyzed. In addition, for the cyanobacteria species, Anabaena flos

- aquae , particulate matter was observed, the EC 50 

### and EC 05 

### values fall within range of test concentrations that were not measured. Therefore, there is uncertainty in the actual exposure concentrations for these two non

- vascular aquatic studies. As the EC 50 

### value for cyanobacteria is close to the EC 50 

### value for green algae, there is uncertainty in which speci es may be more sensitive to sulfosulfuron exposure. Due to the fact that aquatic vascular and non

- vascular plant species are sensitive to sulfosulfuron exposure, and sulfosulfuron is applied in many different scenarios where drift or runoff is expected to enter aquatic ecosystem, there is uncertainty in whether the reported

### 56

toxicity data are appropriate for evaluating risk.

Practical Utility of the Data How will the data be used? The data will be used to estimate potential risks to non

- target aquatic plants, including the likelihood of potential risks to endangered species, either by direct effects or by indirect effects, and to reduce uncertainties associated with the current ecol ogical risk assessment. By refining the assessment, the Agency will be able to determine whether current labeling is appropriate and whether further mitigation is
necessary.

How could the data impact the Agency ’ s future decision

- making? If future risk assessments, including listed species assessments, are performed without these data, the Agency would have to assume that sulfosulfuron “may affect” listed aquatic non

- target plants directly (and listed species from other taxa indirectly), and use of sulfo sulfuron and its formulated products may need to be restricted in areas where listed species could be exposed. These data, once submitted, will allow the Agency to further characterize the risk of sulfosulfuron to aquatic ecosystems. Primary producers (i. e. plants) provide oxygen, food and habitat vital to ecological processes. Therefore, a solid understanding of the potential risks to plants is essential in order to assess the environmental risks the use of sulfosulfuron may pose. D efining an action are a for endangered species and exploring risk mitigation strategies may be underestimated without these data. The lack of these data could limit the knowledge and flexibility the Agency and registrants have in coming into compliance with the Endangered Spec ies Act and could result in underestimating mitigation for sulfosulfuron.

### 57

Guideline Number: none Study Titles: Special Study for Non

- Target Plant Reproductive Toxicity Rationale for Requiring the Data As stated in the Problem Formulation, investigations/studies have indicated a small percentage of the label application rate of low dose high potency herbicides such as sulfonylureas (e.g. sulfosulfuron ) may impact the reproduction of non

- target terrestria l plants. However, there are no available data on adverse reproductive impacts to terrestrial plants from sulfosulfuron residues due to spray drift. Terrestrial plant reproductive toxicity data would help to screen for potential plant risks associated wi th sulfosulfuron use. Plants form the basis of most habitats and contribute significantly to overall environmental quality. T he loss of plant reproductive output could potentially have an adverse effect on animals, both invertebrates and vertebrates, as ma ny are dependent on plant reproduction for a food source and for habitat quality and
structure. A solid understanding of the potential risks to plants is therefore essential for sound environmental management. A study protocol must be submitted for review and approved by the Agency prior to initiation of the study. Practical Utility of the Data How will the data be used?

Guideline Number: 850.4400 Study Titles: Aquatic Vascular Plant Growth ( Lemna gibba )

– Tiers I/II Test Substance: Major degradates

– , sulfamic acid, sulfone, oxamic acid, aminopyrimidine and desmethyl sulfosulfuron Rationale for Requiring the Data No toxicity data are currently available to assess the risk of the sulfosulfuron major degradates sulfamic acid, sulfone, oxamic acid, aminopyrimidine and desmethyl sulfosulfuron to aquatic vascular plants. Sulfosulfuron is applied in many different scenarios where drift is expected to enter aquatic ecosystems. Sulfamic acid, sulfone, oxamic acid a nd aminopyrimidine form via aqueous photolysis (21, 28, 15.6 and 28%, respectively) and there is a likelihood of movement of the parent to the aquatic environment via spray drift and subsequent formation of these degradates. Desmethyl sulfosulfuron forme d in the aerobic aquatic metabolism study (14%) and may form after spray drift exposure of parent to aquatic systems. Given the high likelihood of exposure to the degradates and the lack of any data evaluating the toxicity of these degradates, there is a l ikelihood that degradates may retain the phytotoxic properties of the parent. Tier I testing is required, followed by Tier II if required by Tier I results as specified in Tier I guidelines, to allow for a determination of whether or not the major degrada tes sulfamic acid, sulfone, oxamic acid, aminopyrimidine and desmethyl sulfosulfuron are toxic to aquatic vascular plants. Practical Utility of the Data How will the data be used? The data will be used to estimate potential risks to aquatic vascular plants, including the likelihood of potential risks to endangered species, either by direct effects or by indirect effects, and to reduce uncertainties associated with the current ecolog ical risk assessment. By refining the assessment, the Agency will be able to determine whether current labeling is appropriate and whether further mitigation is necessary.

How could the data impact the Agency’s future decision

- making? Because aquatic v ascular plants form the basis of the food chain for aquatic habitats and significantly contribute to overall water quality, a solid understanding of the potential risks to aquatic plants is essential for sound environmental risk management decision

- making. These data, once submitted, will

### 58

The d ata will be used to estimate potential reproductive risks to non

- target terrestrial plants, including the likelihood of potential risks to endangered species, either by direct effects or by indirect effects, and to reduce uncertainties associated with the current ecological risk assessment. By refining the assessment, the Agency will be able to determine whether current labeling is appropriate and whether further mitigation is necessary. In the absence of this data, risks to terrestrial plants will be pre sumed.

How could the data impact the Agency’s future decision

- making? These data, once submitted, should allow the Agency to characterize the risk posed to plant reproductive processes from sulfosulfuron in terrestrial ecosystems. Primary producers ( i.e. plants) provide food and habitat vital to ecological processes. Therefore, a solid understanding of the potential risks to non

- target plants is essential in order to assess the environmental risks the use of sulfosulfuron may pose. If the data indicate that sulfosulfuron poses significant risks to these non

- target plant species, the Agency may explore additional decision options to minimize the risks to these species. The lack of these data will limit the flexibility the Agency and registrants have in c omplying with the Endangered Species Act and could result in use restrictions for sulfosulfuron which may otherwise be avoided, or which are unnecessarily

severe. allow the Agency to better characterize the risk of sulfosulfuron ’s metabolites to aquatic ecosystems. Primary producers ( i.e. plants) provide oxygen, food and habitat vital to ecological processes. Therefore,

a solid u nderstanding of the potential risks to aquatic plants is essential in order to assess the environmental risks the use of the sulfosulfuron, as a sulfonylurea herbicide, and its resulting metabolites,
may pose. If the data indicates that sulfosulfuron ’s de gradates poses a significant risk to aquatic vascular plants inhabiting water bodies, the Agency may explore additional decision options to minimize the risk of sulfosulfuron to aquatic vascular plants

. The lack of these data will limit the flexibility the Agency and registrants have in complying with the Endangered Species Act and could result in use restrictions for sulfosulfuron which may otherwise be avoided, or which are unnecessarily severe.



## 19.0 References

Asghari, J.B. and J.O. Evans. 1992a. Dyer’s woad ( Isatis tinctoris L. ) pollen viability is reduced by metsulfuron methyl application. Research Progress Report of the Western Society of Weed Science. Meeting March 9

- 12, 1992. Salt Lake City, UT. pp. VI

- 4

- VI

- 5.

Asghari, J.B. and J.O. Evans. 1992b. Effect of metsulfuron me thyl on seed formation and viability of Dyer’s woad ( Isatis tinctoria L.) in the field.. Research Progress Report of the Western Society of Weed Science. Meeting March 9

- 12, 1992. Salt Lake City, UT. Pp. III

178

- II

- 179.

Asghari, J.B., J.O. Evans, and S.A. Dewey. 1993. Dyer’s woad seed production and germinability reduced by sulfonylurea herbicides.

Bhatti, M.A., K. Al

- Khatib, A.S. Felsot, R. Parker, S. Kadir. 1995. Effects of simulated chlorsulfuron drift on fruit yield and quality of sweet cherries ( Prunus avium L.). Environmental Toxicology and Chemistry 14(3): 537

- 544.

### 59

Boutin, C., H.B. Lee, E.T. Peart, P.P. Batchelor, and R.J. Maguire. 2000. Effects of the sulfonylurea herbicide metsulfuron methyl on growth and reproduction of five we tland and terrestrial plant species. Environmental Toxicology and Chemistry 19(10): 2532

- 2541.

Fletcher J.S., T. G. Pfleeger and H.C. Ratsch 1993. Potential Environmental Risks Associated with the New Sulfonylurea Herbicides. Environ. Sci. Technol . 27(10 ): 2250

- 2252.



### Fletcher, J.S., T.G. Pfleeger, and H.C. Ratsch. 1995. Chlorsulfuron influence on garden pea reproduction. Physiologia Plantarum 94: 261

- 267.

Fletcher, J.S., T.G. Pfleeger, H.C. Ratsch, and R.Hayes. 1996. Potential impact of low levels of chlorsulfuron and other herbicides on growth and yield of nontarget plants. Environmental Toxicol ogy and Chemistry 7: 1189

- 1196.

Liping Wei

, Hongxia Yu

, Yue Sun

, Jianfang Fen , and Liansheng Wang . 1998. The Effects of Three Sulfonylurea Herbicides and Their Degradation Products on the Green Algae Chlorella pyrenoidosa. Chemosphere 37 (4): 747

- 751.

Mayer, D. and C. Johansen. 1990. Pollinator Protection: A Bee & Pesticide Handbook .Wicwas Press. C heshire, Conn. p. 161

. U.S. Environmental Protection Agency. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of Research and Development, Washington, D.C. EPA/630/R

- 95/002F. April 1998.

United States Environmental Protec tion Agency (EPA). 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency, Endangered and Threatened Species Effects Determination. Office of Prevention, Pesticides and Toxic Su bstances, Office of Pesticide Programs, Washington, D.C., January 23, 2004.

United States Environmental Protection Agency (EPA). 200 5 . Environmental Fate and Effects Division, May 10, 2005

. Revised Environmental Fate and Ecological Risk Assessment of Chlorsulfuron . DP Barcode. D330621

.

### 60

Appendix A . MRID Bibliography

Guideline: 61

- 1 Chemical Identity

MRID: 44295702 Itoh, S.; Tabuchi, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 1 of 3: Product Identity and Composition: Final Report: Lab Project Number: TKM

- 19

- PC: RD 1353. Unpublished study prepared by Takeda Chemical Industries, Ltd. 155 p.

MRID: 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbicide Formulation : Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the Registration of MON 37525 Herbicide: Lab Project Number: PC1 3

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 61

- 2 Description of Beginning Materials and Manufacturing Proces

MRID: 44295702 Itoh, S.; Tabuchi, T. (1996) Product Chemistry Data for TKM

- 19 (MON3750 0): Part 1 of 3: Product Identity and Composition: Final Report: Lab Project Number: TKM

- 19

- PC: RD 1353. Unpublished study prepared by Takeda Chemical Industries, Ltd. 155 p.

MRID: 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbicide Formulation: Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the Registration of MON 37525 Herbicide: La b Project Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 61

- 3 Discussion of Formation of Impurities

M RID: 44295702 Itoh, S.; Tabuchi, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500 ): Part 1 of 3: Product Identity and Composition: Final Report: Lab Project Number: TKM

- 19

- PC: RD 1353. Unpublished study prepared by Takeda Chemical Industries, Ltd. 155 p.

MRID: 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbi cide Formulation: Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the Registration of MON 37525 Herbicide: Lab Pro ject Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 62

- 1 Preliminary Ana lysis

MRID: 44295703 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 2 of 3: Analysis and Cert ification of Product Ingredients: Lab Project Number: TKM

- 19

- PC: MSL 14299: 6155

- 104. Unpublished study prepared by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 390 p.

MRID: 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbicide Formulation: Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the Registration of MON 37525 Herbicide: Lab Project Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 62

- 2 Certification of limits

### 61

MRID: 44295703 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Par t 2 of 3: Analysis and Certification of Product Ingredients: Lab Project Number: TKM

- 19

- PC: MSL 14299: 6155

- 104. Unpublished study prepared by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 390 p.

MRID: 44295705 Triebe, F . (1996) Product Chemistry Study for MON 37532 Herbicide Formulation: Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Supp ort the Registration of MON 37525 Herbicide: Lab Project Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 62

- 3 Analytical Method

MRID: 44295703 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 2 of 3: Analysis and Certification of Product Ingredients: Lab Project Number: TKM

- 19

- PC: MSL 14299: 6155

- 104. Unpublished study prepared by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 390 p.

MRID : 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbicide Formulation: Lab Project Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

Guideline: 63

- 0 Reports of Multiple ph ys/chem Characteristics

MRID: 44295702 Itoh, S.; Tabuchi, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 1 of 3: Product Identity and Composition: Final Report: Lab Project Number: TKM

- 19

- PC: RD 1353. Unpublished study prepared by Takeda Chemical Industries, Ltd. 155 p.

MRID: 44295703 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 2 of 3: Analysis and Certification of Product Ingredients: Lab Project Number: TKM

- 19

- PC: MSL 14299: 6155

- 104. Unpublished study
prepa red by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 390 p.

MRID: 44295704 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 3 of 3: Physical and Chemical Characteristics: (Final Report): Lab Project Nu mber: TKM

- 19

- PC: MSL 14299: 6155

- 102. Unpublished study prepared by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 354 p.

MRID: 44295705 Triebe, F. (1996) Product Chemistry Study for MON 37532 Herbicide Formulation: Lab P roject Number: RD 1353: MSL 14563: PC13

- 96

- 1. Unpublished study prepared by Monsanto Co. and Notox B. V. 114 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the Registration of MON 37525 Herbicide: Lab Project Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

Guideline: 63

- 17 Storage stability

MRID: 44295704 Yanai, T. (1996) Product Chemistry Data for TKM

- 19 (MON37500): Part 3 of 3: Physical and Chemical Characteristics: (Fi nal Report): Lab Project Number: TKM

- 19

- PC: MSL 14299: 6155

- 102. Unpublished study prepared by Takeda Chemical Industries, Ltd.; Monsanto Co.; and Hazleton Wisconsin, Inc. 354 p.

MRID: 45116101 Triebe, F. (2000) Product Chemistry Data to Support the R egistration of MON 37525 Herbicide: Lab Project Number: PC13

- 99

- 06

- 0: MSL

- 16481: 1500. Unpublished study prepared by Monsanto Company. 50 p.

MRID: 45411301 Triebe, F. (2001) Product Chemistry Data for MON 37525 Herbicide: Storage Stability and Corros ion Characteristics: Lab Project Number: PC13

- 99

- 06

- D: MSL

- 16974. Unpublished study prepared by Monsanto Company. 25 p. {OPPTS 830.6317 and 830.6320}

MRID: 45643401 Van Rijsbergen, L. (1998) Determination of the Stability of MON 37532 Over 2 Years Und er Ambient Conditions: Lab Project Number: 161854: 55512: 1542. Unpublished study prepared by Notox B.V. 54 p.

Guideline: 63

- 20 Corrosion characteristics

### 62

MRID: 45411301 Triebe, F. (2001) Product Chemistry Data for MON 37525 Herbicide: Storage Stability and Corrosion Characteristics: Lab Project Number: PC13

- 99

- 06

- D: MSL

- 16974. Unpublished study prepared by Monsanto Company. 25 p. {OPPTS 830.6317 and 830.6320}

Guideline: 71

- 1 Avian Single Dose Oral Toxicity

MRID: 44295768 Campbell, S.; Beavers, J. (1994) MON 37500: An Acute Oral Toxicity Study with the Northern Bobwhite: Final Report: Lab Project Number: WL

- 94

- 070: 139

- 386: RD 1353. Unpublished study prepared by Wildlife International Ltd. 28 p.

MRID: 44295769 Campbell, S.; Beavers, J. (1995) MON 37500: An Acute Oral Toxicity Study with the Mallard: (Final Report): Lab Project Number: WL

- 94

- 217: 139

- 389: RD 1353. Unpublished study prepared by Wildlife International Ltd. 27 p.

Guideline: 71

- 2 Avian Dietary Toxicity

MRID: 44295770 Campbell, S.; Beavers, J. (1994) MON 37500: A Dietary LC50 Study with the Northern Bobwhite: (Final Report): Lab Project Number: WL

- 94

- 068: 139

- 384: RD 1353. Unpublished study prepared by Wildlife Internatio nal Ltd. 36 p.

MRID: 44295771 Campbell, S.; Beavers, J. (1994) MON 37500: A Dietary LC50 Study with the Mallard: (Final Report): Lab Project Number: WL

- 94

- 069: 139

- 385: RD 1353. Unpublished study prepared by Wildlife International Ltd. 37 p.

Guide line: 71

- 4 Avian Reproduction

MRID: 44295772 Frey, L.; Chafey, K.; Jacobs, R.; et al. (1996) MON 37500: A Reproduction Study with the Northern Bobwhite (Colinus virginianus): (Final Report): Lab Project Number: WL

- 95

- 117: 139

- 410: RD 1353. Unpubli shed study prepared by Wildlife International Ltd. 159 p.

MRID: 44295773 Frey, L.; Chafey, K.; Jacobs, R.; et al. (1996) MON 37500: A Reproduction Study with the Mallard (Anas platyrhynchos): (Final Report): Lab Project Number: WL

- 95

- 232: 139

- 411: RD 1353. Unpublished study prepared by Wildlife International Ltd. 157 p.

Guideline: 72

- 1 Acute Toxicity to Freshwater Fish

MRID: 44295774 Graves, W.; Swigert, J. (1994) MON 37500: A 96

- Hour Static Acute Toxicity Test with the Rainbow Trout (Onco rhynchus mykiss): (Final Report): Lab Project Number: WL

- 94

- 080: 139A

- 167: RD 1353. Unpublished study prepared by Wildlife International Ltd. 40 p.

MRID: 44295775 Graves, W.; Swigert, J. (1994) MON 37500: A 96

- Hour Static Acute Toxicity Test with the Bluegill (Lepomis macrochirus): (Final Report): Lab Project Number: WL

- 94

- 081: 139A

- 168: RD 1353. Unpublished study prepared by Wildlife International Ltd. 40 p.

Guideline: 72

- 2 Acute Toxicity to Freshwater Invertebrates

MRID: 44295776 Graves, W.; Swigert, J. (1994) MON 37500: A 48

- Hour Static Acute Toxicity Test with the Cladoceran (Daphnia magna): (Final Report): Lab Project Number: WL

- 94

- 082: 139A

- 169: RD 1353. Unpublished study prepared by Wildlife International Ltd. 40 p.

Guideline: 72

- 3 Acute Toxicity to Estuarine/Marine Organisms

MRID: 44295777 Graves, W.; Swigert, J. (1995) MON 37500: A 96

- Hour Static Acute Toxicity Test with the Saltwater Mysid (Mysidopsis bahia): (Final Report): Lab Project Number: W L

- 94

- 391: 139A

- 181: RD 1353. Unpublished study prepared by Wildlife International Ltd. 39 p.

### 63

MRID: 44295778 Graves, W.; Swigert, J. (1995) MON 37500: A 96

- Hour Shell Deposition Test with the Eastern Oyster (Crassostrea virginica): (Final Report): Lab Project Number: WL

- 94

- 393: 139A

- 180: RD 1353. Unpublished study prepared by Wildlife International Ltd. 39 p. MRID: 44309304 Graves, W.; Swigert, J. (1995) MON 37500: A 96

- Hour Static Acute Toxicity Test with the Sheepshead Minnow (Cyprinodon variegat us): Lab Project Number: WL

- 94

- 392: 139A

- 182: RD 1353. Unpublished study prepared by Wildlife International Ltd. 39 p.

Guideline: 72

- 4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID: 44295779 Graves, W.; Mank, M.; Swigert, J. (1996) MON 37500: An Early Life

- Stage Toxicity Test with the Rainbow Trout (Oncorhynchus Mykiss): (Final Report): Lab Project Number: WL

- 95

- 252: 139A

- 192: RD 1353. Unpublished study prepared by Wildlife International Ltd. 82 p.

MRID: 44295780 Graves, W.; Mank, M.; Swigert, J. (1996) MON 37500: A Static

- Renewal Life

- Cycle Toxicity Test with the Cladoceran (Daphnia magna): (Final Report): Lab Project Number: WL

- 96

- 043: 139A

- 194: RD 1353. Unpublished study prepared by Wildlife International Ltd. 77 p.

Guideline: 81

- 1 Acute oral toxicity in rats

MRID: 44295737 Bonnette, K. (1993) Acute Oral Toxicity Study in Rats with MON 37500: (Final Report): Lab Project Number: SB

- 92

- 480: 3044. 391: RD 1353. Unpublished study prepared by Springborn Laborat ories, Inc. 19 p.

MRID: 44295738 Blaszcak, D. (1995) Acute Oral Toxicity Study in Rats with MON 37532: (Final Report): Lab Project Number: PL

- 95

- 030: 95

- 1156: RD 1353. Unpublished study prepared by Pharmaco LSR. 20 p.

MRID: 45116102 Blaszcak, D. (1999) MON 37525: Acute Oral Toxicity Study in Rats: Lab Project Number: HU

99

- 174: 99

- 0529: 1500. Unpublished study prepared by Huntingdon Life Sciences. 28 p. {OPPTS 870.1100}

Guideline: 81

- 2 Acute dermal toxicity in rabbits or rats

MRID: 44 295739 Bonnette, K. (1993) Acute Dermal Toxicity Study in Rats with MON 37500: (Final Report): Lab Project Number: SB

- 92

- 480: 3044.392: RD 1353. Unpublished study prepared by Springborn Laboratories, Inc. 17
p.

MRID: 44295740 Blaszcak, D. (1995) Acu te Dermal Toxicity Study in Rats with MON 37532: Lab Project Number: PL

- 95

- 031: 95

- 1157: RD 1353. Unpublished study prepared by Pharmaco LSR. 21 p.

MRID: 45116103 Blaszcak, D. (1999) MON 37525: Acute Dermal Toxicity Study in Rats: Lab Project Number: HU

- 99

- 175: 99

- 0530: 1500. Unpublished study prepared by Huntingdon Life Sciences. 26 p. {OPPTS 870.1200}

Guideline: 81

- 3 Acute inhalation toxicity in rats

MRID: 44295745 Bechtel, C. (1994) (Amended) Report for Acute Inhalation Study (in Rats) of MON 37500 Herbicide: Lab Project Number: ML

- 94

- 003: EHL 94004: RD 1353. Unpublished study prepared by Monsanto Co. 41 p.

MRID: 44295746 Bechtel, C. (1995) Ac ute Inhalation Study (in Rats) of MON 37532: Lab Project Number: ML

95

- 035: EHL 95012: RD 1353. Unpublished study prepared by Monsanto Co. 40 p.

MRID: 45116104 Bechtel, C. (2000) Acute Inhalation Study of MON 37525 in Rats: Lab Project Number: MSE

- N 9 9057: ML

- 99

- 166: MSL

- 16575. Unpublished study prepared by Monsanto Company, Metabolism and Safety Evaluation

- Newstead. 43 p. {OPPTS 870.1300}

Guideline: 81

- 4 Primary eye irritation in rabbits

### 64

MRID: 44295741 Bonnette, K. (1993) Primary Eye Irri tation Study in Rabbits with MON 37500: (Final Report): Lab Project Number: SB

- 92

- 480: 3044.393: RD 1353. Unpublished study prepared by Springborn Laboratories, Inc. 19 p.

MRID: 44295742 Blaszcak, D. (1995) Primary Eye Irritation Study in Rabbits wit h MON 37532: Lab Project Number: PL

- 95

- 032: 95

- 1159: RD 1353. Unpublished study prepared by Pharmaco LSR. 24 p.

MRID: 45116105 Blaszcak, D. (1999) MON 37525: Primary Eye Irritation Study in Rabbits: Lab Project Number: HU

- 99

- 176: 99

- 0532: 1500. Unpu blished study prepared by Huntingdon Life Sciences. 33 p. {OPPTS 8700.2400} Guideline: 81

- 5 Primary dermal irritation

MRID: 44295743 Bonnette, K. (1993) Primary Skin Irritation Study in Rabbits with MON 37500: (Final Report): Lab Project Number : SB

- 92

- 480: 3044.394: RD 1353. Unpublished study prepared by Springborn Laboratories, Inc. 16 p.

MRID: 44295744 Blaszcak, D. (1995) Primary Dermal Irritation Study in Rabbits with MON 37532: Lab Project Number: PL

- 95

- 033: 95

- 1158: RD 1353. Unpublis hed study prepared by Pharmaco LSR. 20 p.

MRID: 45116106 Blaszcak, D. (1999) MON 37525: Primary Dermal Irritation Study in Rabbits: Lab Project Number: HU

- 99

- 177: 99

- 0531: 1500. Unpublished study prepared by Huntingdon Life Sciences. 27 p. {OPPTS 8 70.2500}

Guideline: 81

- 6 Dermal sensitization

MRID: 44295747 Bonnette, K. (1993) Dermal Sensitization Study in Guinea Pigs with MON 37500

-- Modified Buehler Design: Lab Project Number: SB

- 92

- 481: 3044.395: RD 1353. Unpublished study prepared by Springborn Laboratories, Inc. 22 p.

MRID: 44295748 Blaszcak, D. (1995) Guinea Pig Maximization Test with MON 37532: Lab Project Number: PL

95

- 034: 95

- 1160: RD 1353. Unpublished study prepared by Pharmaco LSR. 31 p.

MRID: 45116107 Blaszcak, D. (1999) MON 37525: Skin Sensitization in Guinea Pigs (Buehler Method): Lab Project Number: HU

- 99

- 178: 99

- 0533: 1500. Unpublished study prepared by Huntingdon Life Sciences. 32 p. {OPPTS 870.2600}

Guideline: 81

- 8 Acut e neurotoxicity screen study in rats

MRID: 44295749 Branch, D.; Thake, D.; Kaempfe, T.; et al. (1997) Acute Neurotoxicity Study of MON 37500 in Sprague

- Dawley Rats: Lab Project Number: EHL 95100: MSL 14959: RD 1353. Unpublished study prepared by Monsan to Co. 292 p.

Guideline: 82

- 1 Subchronic Oral Toxicity: 90

- Day Study

MRID: 44295750 Naylor, M.; Thake, D. (1995) Pilot Three Month Study of MON 37500 Administered in Feed to Sprague

- Dawley Rats: Lab Project Number: ML

- 93

- 63: EHL 93002: RD 1353. Unpublished study prepared by Monsanto Co. 486 p.

MRID: 44295751 Naylor, M.; Thake, D. (1996) Three Month Study of MON 37500 Administered by Capsule to Beagle Dogs: Lab Project Number: ML

- 94

- 324: EHL 94108: RD 1353. Unpublished study prepared by Mo nsanto Co. 339 p.

Guideline: 82

- 2 21

- day dermal

- rabbit/rat

MRID: 44295752 Naylor, M.; Thake, D. (1997) Rangefinding and One Month Dermal Study of MON 37500 in CD Rats: Lab Project Number: ML

- 96

- 115: EHL 96050: EHL 96051. Unpublished study prepa red by Monsanto Co. 260 p.

### 65

MRID: 44443701 Naylor, M. (1997) Addendum to: Rangefinding and One Month Dermal Study of MON 37500 in CD Rats: Lab Project Number: ML

- 96

- 115: EHL 96050/96051: MSL 15001. Unpublished study prepared by Monsanto Co. 12 p.

Gu ideline: 82

- 7 Subchronic Neurotoxicity

MRID: 44295753 Kaempfe, T.; Thake, D.; Branch, D.; et al. (1997) Subchronic Neurotoxicity Study of MON 37500 Administered in Feed to Sprague

- Dawley Rats: Lab Project Number: ML

- 96

- 045: EHL 96012: MSL 14915. U npublished study prepared by Monsanto Environmental Health Lab. 389 p.

Guideline: 83

- 1 Chronic Toxicity

MRID: 44295754 Naylor, M.; Ruecker, F. (1997) One Year Study of MON 37500 Administered by Capsule to Beagle Dogs: Lab Project Number: ML

- 95

- 199: EHL 95042: MSL 15007. Unpublished study prepared by Monsanto Co. and Experimental Pathology Laboratories, Inc. 446 p.

MRID: 44295759 Naylor, M.; Ruecker, F. (1997) Combined Chronic Toxicity/Oncogenicity Study of MON 37500 Administered in the Diet to Sprague

- Dawley Rats: Lab Project Number: ML

- 94

- 118: EHL 94051: RD 1353. Unpublished study prepared by Monsanto Co. 2309 p.

MRID: 44443702 Naylor, M. (1997) Addendum to: Combined Chronic Toxicity/Oncogenicity Study of MON 37500 Administered in the Diet to Sprague

- Dawley Rats: Lab Project Number: ML

- 96

- 118: EHL 94051: 82166. Unpublished study prepared by Monsanto Co. 8 p.

MRID: 44532801 Naylor, M. (1998) Addendum to: One Year Study of MON 37500 Administered by Capsule to Beagle Dogs: Lab Project Number: ML

- 95

- 199: EHL 95042. Unpublished study prepared by Monsanto Co. 8 p.

MRID: 45079602 Dubelman, S. (2000) Determina tion of Sulfosulfuron Concentration in Rat Bladder Calculi (Addendum to: Combined Chronic Toxicity/Oncogenicity Study of Mon 37500 Administered in the Diet to CD

- 1 Sprague

- Dawley Rats): Lab Project Number: ML

- 94

- 118: EHL 9051: MSL

- 14843. Unpublished study prepared by Monsanto Co. 51 p.

Guideline: 83

- 2 Oncogenicity

MRID: 44295755 Naylor, M.; Thake, D. (1997) Oncogenicity Study of MON 37500 Administered in Diet to CD

- 1 Mice for 18 Months: Lab Project Number: ML

- 94

- 119: EHL 94052: MSL 15013. Unpu blished study prepared by Monsanto Co. and Experimental Pathology Laboratories, Inc. 1726 p.

MRID: 44295759 Naylor, M.; Ruecker, F. (1997) Combined Chronic Toxicity/Oncogenicity Study of MON 37500 Administered in the Diet to Sprague

- Dawley Rats: Lab P roject Number: ML

- 94

- 118: EHL 94051: RD 1353. Unpublished study prepared by Monsanto Co. 2309 p.

MRID: 44443702 Naylor, M. (1997) Addendum to: Combined Chronic Toxicity/Oncogenicity Study of MON 37500 Administered in the Diet to Sprague

- Dawley Rats: L ab Project Number: ML

- 96

- 118: EHL 94051: 82166. Unpublished study prepared by Monsanto Co. 8 p.

MRID: 44532803 Naylor, M. (1998) Addendum to: Oncogenicity Study of MON 37500 Administered in Diet to CD

- 1 Mice for 18 Months: Lab Project Number: ML

- 94

- 1 19: EHL 94052. Unpublished study prepared by Monsanto Co. 24 p.

MRID: 45079601 Hard, G. (1999) Expert Report on Renal Histopathologic Changes in a Mouse Study with MON 37500 (Sulfosulfuron): Addendum to Oncogenicity Study of Mon 37500 Administered in Diet to CD

- 1 Mice for 18 Months: Lab Project Number: ML

- 94

- 119: MSL 15013: 1503. Unpublished study prepared by Monsanto Co. 10 p.

MRID: 45079602 Dubelman, S. (2000) Determination of Sulfosulfuron Concentration in Rat Bladder Calculi (Addendum to: Co mbined Chronic Toxicity/Oncogenicity Study of Mon 37500 Administered in the Diet to CD

- 1

### 66

Sprague

- Dawley Rats): Lab Project Number: ML

- 94

- 118: EHL 9051: MSL

- 14843. Unpublished study prepared by Monsanto Co. 51 p.

MRID: 46950601 Naylor, M.; Thake, D. ( 1997) Oncogenicity Study of MON 37500 Administered in Diet to CD

- 1 Mice for 18 Months. Unpublished study prepared by University of Nebraska. 7 p.

Guideline: 83

- 3 Teratogenicity

-- 2 Species

MRID: 44295756 Holson, J. (1994) A Developmental Study of MON 37500 in Rats: Lab Project Number: WI

- 93

- 261: WIL

- 50226: RD 1353. Unpublished study prepared by WIL Research Laboratories, Inc. 277 p.

MRID: 44295757 Holson, J. (1994) A Developmental Study of MON 37500 in Rabbits: Lab Project Number: WI

94

- 0 02: WIL

- 50227: RD 1353. Unpublished study prepared by WIL Research Laboratories, Inc. 279 p.

MRID: 44532802 Holson, J.; Naylor, M. (1998) Addendum to: A Developmental Study of MON 37500 in Rabbits: Lab Project Number: WI

- 94

- 002: WIL

- 50227. Unpublished study prepared by WIL Research Labs., Inc. 118 p.

Guideline: 83

- 4 2

- generation repro.

- rat

MRID: 44295758 Naylor, M.; Thake, D. (1996) Two Generation Reproduction Study of MON 37500 Administered in the Diet to Albino Rats: Lab Project Number: ML

- 94

- 120: EHL 94053: RD 1353. Unpublished study prepared by Monsanto Co. and Experimental Pathology Laboratories, Inc. 1194 p. Guideline: 84

- 2 Interaction with Gonadal DNA

MRID: 44280201 Yoshida, N. (1996) Chromosomal Aberration Test of TKM

- 19 Using Cultured Mammalian Cells: Final Report: Lab Project Number: T95

- 2337: T

- 4500: K06

- 0494. Unpubl ished study prepared by Hita Research Labs. 28 p.

MRID: 44295760 Stegeman, S.; Warren, J.; Kier, L. (1995) Ames/Salmonella Mutagenicity Assay of MON 37500: Lab Project Number: ML

- 94

- 004: EHL 94002: RD 1353. Unpublished study prepared by Monsanto Co. 59 p.

MRID: 44295761 Stegeman, S.; Kier, L.; Asbury, K.; et al. (1996) CHO/HGPRT Gene Mutation Assay of MON 37500: Lab Project Number: ML

- 95

- 200: EHL 95054: RD 1353. Unpublished study prepared by Monsanto Co. 64
p.

MRID: 44295762 Murli, H. (1996) Chromosome Aberration Study in Human Whole Blood Lymphocytes with a Confirmatory Assay with Multiple Harvests with MON 37500: Revised Final Report: Lab Project Number: HL

- 95

- 201: 17146

- 0

- 449CO: RD 1353. Unpublished study prepared by Monsanto Co. and Corn ing Hazleton Inc. 66 p.

MRID: 44295763 Stegeman, S.; Kier, L.; Garrett, S.; et al. (1995) Mouse Bone Marrow Micronucleus Assay of MON 37500: Lab Project Number: ML

- 94

- 005: EHL 94003: RD 1353. Unpublished study prepared by Monsanto Co. 56 p.

MRID: 44295764 Stegeman, S.; Kier, L.; Albin, L.; et al. (1996) Mouse Bone Marrow Assay of (carbon 14) Radiolabeled MON 37500: Lab Project Number: ML

- 95

- 289: EHL 95106: RD 1353. Unpublished study prepared by Monsanto Co. 20 p.

Guideline: 85

- 1 General metabolism

MRID: 44295765 Lau, H.; Kinnett, M.; Albin, L.; et al. (1996) The Absorption, Distribution, Elimination, and Metabolism of MON 37500 in Sprague Dawley Rats Following Oral and Intravenous Administration: Lab Project Number: MSL 14300: EHL 930 41: RD 1353. Unpublished study prepared by Monsanto Co. 504 p.

Guideline: 122

- 2 Aquatic plant growth

### 67

MRID: 44295781 Thompson, S.; Swigert, J. (1996) MON 37500: A 5

- Day Toxicity Test with the Marine Diatom (Skeletonema costatum): (Final Report): Lab Project Number: WL

- 94

- 346: 139A

- 179: RD 1353. Unpublished study prepared by Wildlife International Ltd. 46 p.

MRID: 44295782 Thompson, S.; Swigert, J. (1996) MON 37500: A 5

- Day Toxicity Test with the Freshwater Diatom (Navicula pelliculosa): (Fin al Report): Lab Project Number: WL

- 94

- 347: 139A

- 176: RD 1353. Unpublished study prepared by Wildlife International Ltd. 45 p.

Guideline: 123

- 1 Seed germination/seedling emergence and vegitative vigor

MRID: 44295783 Chetram, R.; Cone, C. (1997) Tier 2 Seed Germination/Seedling Emergence Nontarget Phytotoxicity Study Using MON 37500: Lab Project Number: MSL 14477: 94434: RD 1353. Unpublished study prepared by ABC Laboratories, Pan

- Ag Division. 250 p.

MRID: 44295784 Chetram, R.; Cone, C. (1995) Tier 2 Vegetative Vigor Nontarget Phytotoxicity Study Using MON 37500: Lab Project Number: MSL 14478: 94435: RD 1353. Unpublished study prepared by ABC Laboratories, Pan

- Ag Division. 249 p.

Guideline: 123

- 2 Aquatic plant growth

MRID: 44295785 Thompson, S.; Swigert, J. (1995) MON 37500: A 5

- Day Toxicity Test with the Freshwater Alga (Selenastrum capricornutum): Lab Project Number: WL

- 94

- 096: 139A

- 173: RD 1353. Unpublished study prepared by Wildlife International Ltd. 56 p.

MRID: 44295786 Thompson, S.; Swigert, J. (1996) MON 37500: A 5

- Day Toxicity Test with the Freshwater Alga (Anabaena flos

- aquae): (Final Report): Lab Project Number: WL

- 94

- 348: 139A

- 177: RD 1353. Unpublished study prepared by W ildlife International Ltd. 48 p.

MRID: 44295787 Thompson, S.; Swigert, J. (1996) MON 37500: A 14

- Day Toxicity Test with Duckweed (Lemna gibba G3): (Final Report): Lab Project Number: WL

- 94

- 216: 139A

- 174: RD 1353. Unpublished study prepared by Wildlif e International Ltd. 45 p.

Guideline: 141

- 1 Honey bee acute contact

MRID: 44295788 Palmer, S.; Beavers, J. (1994) MON 37500: An Acute Contact Toxicity Study with the Honey Bee: (Final Report): Lab Project Number: WL

- 94

- 071: 139

- 382A: RD 1353. Unpublished study prepared by Wildlife International Ltd. 19 p.

Guideline: 161

- 1 Hydrolysis

MRID: 44295720 Mayo, B.; Langford

- Pollard, A. (1994) The Hydrolysis of (carbon 14)

- MON 37500: Lab Project Number: MSL 13700: MTO 34/932281: RD 1353. Un published study prepared by Huntingdon Research Centre Ltd. 124 p.

Guideline: 161

- 2 Photodegradation

- water

MRID: 44295721 Kurtzweil, M. (1993) Aqueous Photolysis Studies of MON 37500: Lab Project Number: MSL 12898: RD 1353: 92

- 13

- M33. Unpublis hed study prepared by Monsanto Co. 137 p.

Guideline: 161

- 3 Photodegradation

- soil

MRID: 44295722 Estigoy, L.; Shepler, K. (1996) Photodegradation of (carbon14)MON 37500 in/on Soil by Natural Sunlight: Lab Project Number: MSL 14021: 482W: RD 135 3. Unpublished study prepared by PTRL West, Inc. 112 p.

Guideline: 162

- 1 Aerobic soil metabolism

### 68

MRID: 44295723 McMullan, P.; Lundry, D. (1995) Aerobic Soil Metabolism of MON 37500: Lab Project Number: MSL 13750: RD 1353: 93

- 13

- M1. Unpublished study prepared by Monsanto Co. 205 p.

MRID: 44295724 Mayo, B.; McEwen, A. (1996) The Aerobic Soil Metabolism of (carbon 14)

- MON 37500: Lab Project Number: MSL 14019: MTO 35/942911: RD 1353. Unpublished study prepared by Huntingdon Life Sciences Ltd. 119 p.

Guideline: 162

- 3 Anaerobic aquatic metab.

MRID: 44295725 Skinner, W. (1997) Anaerobic Aquatic Metabolism of (carbon 14)

- MON 37500: Lab Project Number: MSL 14022: 460W: RD 1353. Unpublished study prepared by PTRL West, Inc. 194 p.

Guideline: 162

- 4 Aerobic aquatic metab.

MRID: 44295726 Voelkel, W. (1996) MON 37500: Degradation and Metabolism in Aerobic Aquatic Systems: Lab Project Number: MSL 14023: 379642: RD 1353. Unpublished study prepared by RCC Umweltchemie Ag. 202 p.

Guideline: 163

- 1 Leach/adsorp/desorpt ion

MRID: 44295727 Mayo, B.; McEwen, A. (1995) The Soil Column Leaching of Aged Residues: MON 37500: Lab Project Number: MSL 13702: MTO 37/942626: RD 1353. Unpublished study prepared by Huntingdon Research Centre Ltd. 87 p.

MRID: 44295728 Mayo, B. ; McEwen, A. (1995) (Carbon 14)

- MON 37500: The Adsorption/Desorption on Soil: Lab Project Number: MSL 13701: MTO 38/942137: RD 1353. Unpublished study prepared by Huntingdon Research Centre Ltd. 108 p.

MRID: 44295729 Atkins, R. (1996) Soil Adsorption /Dessorption of (carbon 14)

- CP 180422 by the Batch Equilibrium Method: Lab Project Number: MSL 14409: 974: RD 1353. Unpublished study prepared by PTRL East, Inc. 92 p.

MRID: 44295730 Atkins, R. (1996) Soil Adsorption/Dessorption of (carbon 14)

- CP 147 937 by the Batch Equilibrium Method: Lab Project Number: MSL 14410: 975: RD 1353. Unpublished study prepared by PTRL East, Inc. 91 p.

MRID: 44309303 Nadeau, R.; Sidhu, R. (1997) Adsorption/Desorption Studies of 4,6

- Dimethoxy

- 2

- aminopyrimidine, A Soil Metabolite of MON 37500: Lab Project Number: MSL 14437: RD 1353. Unpublished study prepared by Monsanto Co. 85 p.

Guideline: 164

- 1 Terrestrial field dissipation

MRID: 44295731 Mayo, B.; McEwen, A. (1995) Degradation of (carbon 14)

- MON 37500 o n Three Soils: Lab Project Number: MSL 14020: MTO 40/943154: RD 1353. Unpublished study prepared by Huntingdon Research Centre Ltd. 136 p.

MRID: 44295732 McMullan, P. (1996) Terrestrial Field Dissipation Study with (carbon 14)

- MON 37500: Lab Project Number: RD 1353: MSL 14371. Unpublished study prepared by Monsanto Co., PTRL

- West, Inc. and Plant Sciences, Inc. 521 p.

MRID: 44295733 Steinmetz, J. (1996) Terrestrial Field Soil Dissipation of MON 37500 (1995 Use Season): Lab Project Number: MSL 14192: RD 1353: 95

- 13

- R

- 1. Unpublished study prepared by Monsanto Co. 286 p.

G uideline: 165

- 1 Confined rotational crop

MRID: 44295735 Kurtzweil, M. (1996) Confined Rotational Crop Study with MON 37500: Lab Project Number: MSL 14130: 474W

- 1: RD 1353. Unpublished study prepared by Monsanto Co. and PTRL West, Inc. 367 p.

### 69

MRID: 45096402 Kunda, U. (1998) Stability of MON 37500 Residues in Rotation Crops During Frozen Storage: Lab Project Number: MSL

- 14577: RD 1504: RES

- 082

- 94. Unpublished study prepared by Monsanto Co. 80 p. {OPPTS 860.1380}

Guideline: 165

- 2 Field rotational crop

MRID: 44821802 Kunda, U. (1998 ) Magnitude of the Residues of MON 37500 in Field Rotational Crops: Lab Project Number: MSL

- 14367: 95

- 13

- R

- 5: RD1474. Unpublished study prepared by Monsanto Company and Qualls Agricultural Labs. 352 p. {OPPTS 860.1900}

Guideline: 171

- 4B Residue A nalytical Methods

MRID: 44295710 Lyle, T. (1997) Independent Laboratory Method Validation for the Determination of MON 37500 Residues in Wheat Matrices According to EPA Notice PR 96

- 1 using Monsanto Method No. RES

- 082

- 94, Version No. 2: (Final Report): Lab Project Number: MSL 14948: 95

- 0076: RD 1353. Unpublished study prepared by EN

- CAS Analytical Laboratories. 86 p.

MRID: 44295711 Davis, K. (1996) Independent Laboratory Validation per PR Notice 96

- 1 of Monsanto Method No. RES

- 095

- 96, Version O (De termination of MON 37500 Residues in Meat/Milk Tissues): (Final Report): Lab Project Number: MSL 14836: 43589: RD 1353. Unpublished study prepared by ABC Laboratories, Inc. 93 p.

MRID: 44295712 Lyle, T.; Baldi, B. (1996) Independent Method Validation Ruggedness Trial for the Determination of MON 37500 and Sulfonamide in Water using Monsanto Method No. RES

- 093

- 95, Version No. O, Entitled Analytical Method for the Determination of MON 37500 and its Metabolites in Water: (Final Report): Lab Project Number : MSL 14535: 95

- 0077: RES

- 093

- 95. Unpublished study prepared by EN

- CAS Analytical Laboratories. 76 p.

MRID: 44295713 Nandihalli, U. (1997) FDA Multi

- Residue Method for Testing of MON 37500 and Sulfonamide Metabolite (CP 147937): Lab Project Number: M SL 14955: CHW 6103

- 198: RD 1353. Unpublished study prepared by Corning Hazleton, Inc. 90 p.

MRID: 44309301 Lyle, T.; Baldi, B. (1996) Independent Method Validation Ruggedness Trial for the Determination of MON 37500 in Wheat Matrices using Monsanto M ethod No. RES

- 082

- 94, Version No. 2, Entitled "Analytical Method for the Determination of MON 37500 and Its Metabolites in Wheat": Lab Project Number: MSL 14536: 95

- 0076: RD 1353. Unpublished study prepared by EN

- CAS Analytical Laboratories. 60 p.

MRID : 44821801 Kunda, U.; Habibi

- Goudarzi, S. (1998) Confirmatory Method for MON 37500 RAC Regulatory Enforcement Methods: Lab Project Number: MSL

- 14962: 97

- 13

- R

- 1: RD 1474. Unpublished study prepared by Monsanto Company. 138 p.

Guideline: 171

- 4C Ma gnitude of the Residue [by commodity]

MRID: 44295714 Allan, J. (1996) Stability of MON 37500 Residues in Wheat Raw Agricultural Commodities During Frozen Storage: Lab Project Number: MSL 14394: RD 1353: 94

- 13

- R

- 2. Unpublished study prepared by Monsanto Co. 69 p.

MRID: 44295715 Sidhu, R. (1997) Stability of MON 37500 Residues in Dairy Cow Milk and Meat Tissues During Frozen Storage: Lab Project Number: MSL 14602: RD 1353: 96

- 13

- R

- 3. Unpublished study prepared by Monsanto Co. 110 p.

MRID: 44295716 Kunda, U.; Mueth, M. (1997) Magnitude of the Residues of MON 37500 in Wheat Raw Agricultural Commodities: Lab Project Number: MSL 14396: RD 1353: 94

- 13

- R

- 4. Unpublished study prepared by Monsanto Co. 597 p.

### 70

MRID: 44295717 Kunda, U. (1997) Magnitude of the Residues of MON 37500 in Wheat Processed Commodities: Lab Project Number: MSL 14436: RD 1353: 94

- 13

- R

- 5. Unpublished study prepared by Monsanto Co., American Agricultural Services, Inc. and Crop Guard Research, Inc. 147 p.

MRID: 44295718 Sidhu, R. (1997) Magnitude of MON 37500 Residues in Milk and Edible Tissues of Lactating Dairy Cattle: Lab Project Number: MSL 14559: 95128B: RD 1353. Unpublished study prepared by Monsanto Co. and Southwest Bio

- Labs., Inc. 329 p.

Guideline : 171

- 4A2 Nature of the Residue in Plants

MRID: 44295707 Nadeau, R.; Kurtzweil, M. (1994) Metabolism of MON 37500 in Wheat: Lab Project Number: MSL 13043: 408W: RD 1353. Unpublished study prepared by Monsanto Co. 285 p. Guideline: 171

- 4A3 Nature of the Residue in Livestock

MRID: 44295708 Nadeau, R.; Kinnett, M.; Chott, R.; et al. (1996) Metabolism of MON 37500 in Laying Hens: Final Report: Lab Project Number: MSL 14000: EHL 95020: RD 1353. Unpublished study prepared by Monsanto Co. 20 3 p.

MRID: 44295709 Nadeau, R.; Fujiwara, H.; Solsten, R.; et al. (1995) Metabolism of MON 37500 in Lactating Goats: (Final Report): Lab Project Number: MSL 14001: 41713: RD 1353. Unpublished study prepared by Monsanto Co. 228 p. Guideline: 830.170 0 Preliminary analysis

MRID: 47156801 Ha, S. (2005) Analysis of Sulfosulfuron and Production Impurities in Sulfosulfuron Technical. Project Number: RD/1688, V/28134A. Unpublished study prepared by Valent Dublin Laboratory. 166 p. Guideline: 860 .1500 Crop field trials

MRID: 46753801 Moran, S. (2005) Magnitude of the Residues of Sulfosulfuron and Its Metabolites in Grasses From Pastures and Rangelands After Treatment with MON 37503. Project Number: 04/13/R/1, MSL/19348, 1661. Unpublished study prepared by Carringers, Inc., Monsanto Company and Agricultural Systems Associates. 283 p.

Non

- Guideline Study

MRID: 44280200 Citation: Monsanto Co. (1997) Submission of Toxicology Data in Support of FIFRA 6(a)(2) for MON 37500 Experimental Her bicide. Transmittal of 1 Study.

MRID: 44295700 Citation: Monsanto Co. (1997) Submission of Product Chemistry, Toxicity, Residue, Environmental Fate, Exposure, and Risk Data in Support of the Application for Registration of MON 37500 Herbicide, MON 37503NC Herbicide for Non

- Crop Uses, M ON 37503W Herbicide for Wheat and for Tolerances for MON 37500 (Sulfosulfuron) in Wheat Raw Agricultural Commodities and Animal Products. Transmittal of 90 Studies.

MRID: 44295701 Citation: Dirks, R. (1997) Reduced Risk Pesticide Rationale for Sulfosul furon: Lab Project Number: RD 1353. Unpublished study prepared by Monsanto Co. 234 p.

MRID: 44295706 Citation: Singh, H.; Nadeau, R. (1997) Overview of the Residue Chemistry Studies of MON 37500: Lab Project Number: MSL 15046: RD 1353. Unpublished s tudy prepared by Monsanto Co. 25 p.

MRID: 44295719 Citation: Moran, S. (1997) The Environmental Fate of MON 37500: A Review of Laboratory and U. S. Field Studies: Lab Project Number: MSL 15045: RD 1353. Unpublished study prepared by Monsanto Co. 24 p.

MRID: 44295734 Citation: Allan, J. (1996) Stability of Residues of MON 37500 and its Major Metabolite in Soil During Frozen Storage: Lab Project Number: MSL 14395: RD 1353: RES

- 090

- 95. Unpublished study prepared by Monsanto Co. 72 p.

### 71

MRID: 4429 5736 Citation: Naylor, M. (1997) MON 37500: Toxicology Overview and Risk Assessment: Lab Project Number: RD 1353. Unpublished study prepared by Monsanto Co. 28 p.

MRID: 44295766 Citation: Cowell, J. (1996) Pesticide Handlers Exposure Assessment fo r Uses of MON 37500 Herbicide: Lab Project Number: RD 1353. Unpublished study prepared by Monsanto Co. 15 p.

MRID: 44295767 Citation: McKee, M.; Gustafson, D.; Roloff, M.; et al. (1997) MON 37500: Ecotoxicology Overview and Risk Assessment: Lab Proje ct Number: RD 1353. Unpublished study prepared by Monsanto Co. 14
p.

MRID: 44295789 Citation: Palmer, S.; Beavers, J. (1995) MON 37500: An Acute Oral Toxicity Study with the Honey Bee: (Final Report): Lab Project Number: WL

- 94

- 083: 139

- 390: RD 1353. Unpublished study prepared by Wildlife International Ltd. 21 p.

MRID: 44295790 Citation: Dirks, R. (1997) FQPA Supplemental Information for Sulfosulfuron: Lab Project Number: RD 1379. Unpublished study prepared by Monsanto Co. 11 p.

MRID: 4430 9300 Citation: Monsanto Co. (1997) Submission of Residue, Environmental Fate and Toxicity Data in Support of the Registration and Petition for MON 37500 (Sulfosulfuron) Herbicide. Transmittal of 4 Studies.

MRID: 44309302 Citation: Lyle, T.; Baldi, B. (1996) Independent Method Validation Ruggedness Trial for the Determination of MON 37500 and Sulfonamide in Soil Using Monsanto Method No. RES

- 090

- 95, Version No. O, Entitled "Analytical Method for the Determination of MON 37500 and Its Metabolites in S oil": Lab Project Number: MSL 14534: 95

- 0075: RD 1353. Unpublished study prepared by EN

- CAS Analytical Laboratories. 78 p.

MRID: 44443700 Citation: Monsanto Co. (1997) Submission of Toxicology Data in Support of the Application for Registration of M ON 37500 Technical, MON 37503W and MON 37503NC Herbicide. Transmittal of 2 Studies.

MRID: 44532800 Citation: Monsanto Co. (1998) Submission of Toxicity Data in Support of the Application for Registration of MON 37503W Herbicide and Mon 37503NC Herbic ide and Petition for Tolerance of MON 37500 (Sulfosulfuron) Technical on Wheat. Transmittal of 3 Studies.

MRID: 44636200 Citation: Monsanto Company (1998) Submission of Environmental Fate Data in Support of the Application for Registration of MON 375 00 and MON 37503. Transmittal of 1 Study.

MRID: 44636201 Citation: Dirks, R.; Moran, S. (1998) MON 37500 (Sulfosulfuron) Metabolite Herbicidal Activity: Lab Project Number: RD 1432. Unpublished study prepared by Monsanto Company. 10 p.

MRID: 44665100 Citation: Monsanto Company (1998) Submission of Public Interest Documents in Support of the Application for Registration of Maverick Herbicide, and MON 37500 Technical, and the Petition for Tolerance of MON 37500 in/on Wheat RAC's and Ani mal Products. Transmittal of 3 Studies.

MRID: 44665101 Citation: Dirks, R. (1998) Public Interest Document for Maverick (MON 37500) Herbicide: Volume I: Agro

- Econonmic Benefits: Lab Project Number: RD 1442. Unpublished study prepared by Monsanto Company. 57 p.

MRID: 44665102 Citation: Dirks, R. (1998) Public Interest Document for Maverick (MON 37500) Herbicide: Volume 2: Appendices: Lab Project Number: RD 1442: RD 1353: MSL

- 15046. Unpublished study prepared by Monsanto Company. 252 p.

MRID: 44665103 Citation: Dirks, R. (1998) Pub lic Interest Document for Maverick (MON 37500) Herbicide: Volume 3: References: Lab Project Number: RD 1442. Unpublished study prepared by Monsanto Company. 433 p.

MRID: 44763100 Citation: Monsanto Company (1999) Submission of Pesticide Use Data in Support of the Applications for Registration of Mon 37503 and Mon 37500 Technical and the Petition for Tolerance of Sulfosulfuron in/on Wheat Raw Agricultural Commodities and Animal Products. Transmittal of 1 Study.

### 72

MRID: 44763101 Citation: Honegger, J.; Dirks, R. (1999) Information in Support of the Aerial Application of Maverick Herbicide: Lab Project Number: RD 1465. Unpublished study prepared by Monsanto Company. 94 p.

MRID: 44821800 Citation: Monsanto Company (1999) Submission of Residue C hemistry Data in Support of the Applications for Registration of MON 37503 and MON 37500 Technical and the Petition for Tolerance of Sulfosulfuron in/on Wheat, RACs, and Animal Products. Transmittal of 2 Studies.

MRID: 45079600 Citation: Monsanto Comp any (2000) Submission of Toxicity Data in Support of the Registration of Sulfosulfuron. Transmittal of 2 Studies.

MRID: 45096400 Citation: Monsanto Co. (2000) Submission of Residue Data in Support of the Registration of MON 37500. Transmittal of 2 S tudies.

MRID: 45096401 Citation: Mannion, R.; Moran, S. (2000) Responses to Agency Questions on Sulfosulfuron Limited Field Rotation Crop Study: Lab Project Number: 1504. Unpublished study prepared by Monsanto Co. 8 p. {OPPTS 860.1900}

MRID: 4511 6100 Citation: Monsanto Company (2000) Submission of Product Chemistry and Toxicity Data in Support of the Registration of MON 37525 Herbicide. Transmittal of 7 Studies.

MRID: 45362800 Citation: Monsanto Company (2001) Submission of Toxicity Data i n Support of the Registration of Sulfosulfuron. Transmittal of 1 Study.

MRID: 45362801 Citation: Healy, C. (2001) Studies on the Relevance of Kidney and Urinary Bladder Tumors in Chronic Studies with Sulfosulfuron: Lab Project Number: 1536. Unpublis hed study prepared by Monsanto Company. 15 p.

MRID: 45411300 Citation: Monsanto Company (2001) Submission of Product Chemistry Data in Support of the Registration of MON 37525W Herbicide and MON 37525NC Herbicide. Transmittal of 1 Study.

MRID: 45643400 Citation: Monsanto Company (2001) Submission of Product Chemistry Data in Support of the Registrations of Maverick Herbicide and Outrider Herbicide. Transmittal of 1 Study.

MRID: 45643600 Citation: Monsanto Company (2001) Submission of Toxicity Data in Support of the Amended Registrations of Maverick Herbicide, Outrider Herbicide and Maverick Pro Herbicide. Transmittal of 1 Study.

MRID: 45643601 Citation: Cohen, S.; Arnold, L. (2001) Effects of Dietary Sulfosulfuron on Urinary P arameters and the Bladder in Male Sprague

- Dawley Rats: Lab Project Number: 220: 080100: 1536. Unpublished study prepared by University of Nebraska Medical Center. 112 p.

MRID: 46004100 Citation: Monsanto Company (2003) Submission of Environmental Fat e and Residue Data in Support of the Registration of Halosulfuron

- Methyl. Transmittal of 3 Studies.

MRID: 46004102 Citation: Allan, J. (2002) Validation of a Multiresidue Method For Sulfosulfuron and Halosulfuron Herbicides In Water Using LC/MS/MS. Pr oject Number: 00

- 13

- R

- 3, MSL

- 17534. Unpublished study prepared by Monsanto Agricultural Co. 420 p.

MRID: 46004103 Citation: Allan, J. (2002) Validation of a Multiresidue Method for Sulfosulfuron and Halosulfuron Herbicides in Soil Using LC/MS/MS. Proj ect Number: 00/13/R/2, MSL/17569, ES/ME/405/03. Unpublished study prepared by MONSANTO COMPANY. 353 p.

MRID: 46005900 Citation: Monsanto Company (2003) Submission of Environmental Fate Data in Support of Sulfosulfuron and Halosulfuron. Transmittal of 2 Studies.

### 73

MRID: 46005901 Citation: Allan, J. (2002) Validation of a Multiresidue Method for Sulfosulfuron and Halosulfuron Herbicides in Water Using LC/MS/MS. Project Number: 00/13/R/3, MSL/17534, ES/ME/0404/02. Unpublished study prepared by Monsanto Company. 420 p.

MRID: 46005902 Citation: Allan, J. (2002) Validation of a Multiresidue Method for Sulfosulfuron and Halosulfuron Herbicides in Soil Using LC/MS/MS. Project Number: 00/13/R/2, MSL/17569, ES/ME/0405/03. Unpublished study prepared by Mons anto Company. 353 p.

MRID: 46753800 Citation: Monsanto Company (2006) Submission of Residue Data in Support of the Amended Registration of Maverick Herbicide and the Petition for Tolerance of Sulfosulfuron on Grass Forage, Fodder and Hay. Transmittal of 1 Study.

MRID: 46950600 Citation: Monsanto Co. (2006) Submission of Toxicity Data in Support of the Registrations of Maverick Herbicide and Maverick C/A Herbicide. Transmittal of 1 Study.

MRID: 47156800 Citation: Monsanto Company (2007) Submis sion of Product Chemistry Data in Support of the Registration of MON 37500 Technical. Transmittal of 1 Study.

MRID: 47438900 Citation: Monsanto Company (2008) Submission of Residue Data in Support of the Amended Registration of Maverick Herbicide. Tr ansmittal of 1 Study.

MRID: 47438901 Citation: Moran, S. (2008) Sampling of Bermudagrass Forage from Comparison Trial with and without Surfactant for Sulfosulfuron Residue Analysis. Project Number: REG/07/187, MSL0021114. Unpublished study prepared by Monsanto Company. 44 p.

### 74

Appendix B

. Summary of Structure, Chemical Formulas and Common Names

Table 1. Chemical and Common Name of Sulfosulfuron and its degradation products.

Chemical Name Common Name
N

- [[(4,6

- Dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]

- 2

- (ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide Sulfosulfuron (MON 37500)

N

- [[(4

- Hydroxy

- 6

- dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]

- 2

- (ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide Desmethyl metabolite

N

- [[(Aminoiminomethyl)amino]carbonyl]

- 2

- (ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide Guanidine metabolite

[[(4,6

- Dimethoxy

- 2

- pyrimidinyl)amino]carbonyl]sulfamic acid Sulfamic acid metabolite

(4,6

- Dimethoxy

- 2

- pyrimidinyl)urea Urea metabolite
2

- (Ethylsulfonyl)imidazo[1,2

- a]pyridine

- 3

- sulfonamide Sulfonamide metabolite

4,6

- Dimethoxy

- 2

- pyrimidinamine Aminopyrimidine metabolite

2

- Imino

- α

- oxo

- 1

- (2H)

- pyridineacetic acid Oxamic acid metabolite

N

- (4,6

- dimethoxy

- 2

- pyrimidinyl)

- N’

- hydroxy

urea N

- hydroxy urea

2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine

- 3

- sulfonic acid Sulfonic acid

2

- (ethylsulfonyl)

- imidazo[1,2

- a]pyridine Sulfone

### 75

### 76

Appendix C . Summary of Toxicity Studies for Sulfosulfuron

Table 1 Affect of Sulfosulfuron on Birds

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects (a) Source / Study Classification / Exposure Groups

Sulfosulfuron / 71

- 1 (850.2100)/ Avian Single Dose Oral Toxicity

– Bobwhite Quail ( Colinus virginianus ), 35 wks old ( 182
to 243 grams), intubation / Technical Sulfosulfuron (>98.5%) 14

- d LD 50 = >2,250 mg a.i. /kg

- bw NOAEL = 810 mg a.i./kg

- bw ( No mortality observed, clinical signs of toxicity two highest dose, decrease body weight at highest dose )

Classified as practically nontoxic MRID 44295768 Campbell & Beavers , 19 94 (Unpublished) / Acceptable/ nominal 0 ( corn oil, 0.6mL/100g ), 292, 486, 810, 1350, 2250 mg a.i. /kg

- bw, 10 birds (5 males, 5 females) per group

Sulfosulfuron / 71

- 1 (850.2100)/ Avian Single Dose Oral Toxicity

– Mallard duck (

Anas platyrhynchos ), 25 wks old ( 771 to 1309 grams), intubation / Technical Sulfosulfuron (>98.5%) 14

- d LD 50 = >2,216 mg a.i. /kg

- bw NOAEL = 2,216 mg a.i./kg

- bw ( No mortality observed, no effects on food consumption or body weight observed )

Classified as practically nontoxic MRID 44295769 Campbell & Beavers , 19 95 (Unpublished) / Acceptable/ nominal 0 ( corn oil, 0.6mL/100g ), 288, 479, 798, 1330, 2216 mg a.i. /kg

- bw, 10 birds (5 males, 5 females) per group

Sulfosulfuron / 71

- 2 (850.2200)/ Avian Dietary Toxicity

– Northern Bobwhite ( Colinus virginianus ), 10

- day old chicks / Technical Sulfosul furon (>98.5 % ) 8

- d LC 50 (b) > 5,570 mg a

. i

. /kg

- diet NOAEC = 5,570 mg a.i./kg

- diet ( No mortality observed , no effects on food consumption or body weight observed)

Classified as practically nontoxic MRID 44295770 Campbell & Beavers , 19 94 (Unpublished) / Acceptable / Mean measured: 0 (2% corn oil), 5 40, 961, 1725, 3060, 5570 mg a.i./kg

- diet ; 10 birds per group;

Sulfosulfuron /71

- 2 (850.2200)/ Avian Dietary Toxicity

– Mallard duck (

Anas platyrhynchos ) , 1 0

- day old chicks / Technical Sulfosulfuron (>98.5 % ) 8

- d LC 50 (b) > 5,110 mg a

. i

. /kg

- diet NOAEC = 3,000 mg a.i./kg

- diet ( no mortalit ies observed , no effects on food consumption ; reduction in body weight at highest conc. )

Classified as practically nontoxic MRID 44295771 Campbell & Beavers , 19 94 (Unpublished) / Acceptable / Mean measured: 0 (2% corn oil), 521, 953, 1695, 3000, 5110 mg a.i./kg

- diet ; 10 birds per group;

SULFOSULFURON /850.2300 / Avian Reproduction Toxicity

– Northern Bobwhite ( Colinus virginianus ) , 1 9

- wk old , 21

- wk test duration / Technical Sulfosulfuron (98.5%) NOAEC at least 1229 mg a

. i

. /kg

- diet, highest concentration tested

( No treatment

- related effects were observed on any adult or offspring parameter at any treatment level ) MRID 4 4295772 Frey

, et.al ., 199 6 (Unpublished) / Acceptable Mean measured: 0, 46.9, 247 and 1229 mg ai/kg

- d iet; 16 pairs (1 male and 1 female)

### 77

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects (a) Source / Study Classification / Exposure Groups

SULFOSULFURON /850.2300 / Avian Reproduction Toxicity

– Mallard duck (

Anas platyrhynchos ) , 1 9

- wk old , 22

- wk test duration / Technical Sulfosulfuron (98.5%) NOAEC = 245 mg a.i./kg

- diet LOAEC = 1221 mg a.i./kg

- diet ( Reduced body weight in 14

- d old hatchlings ) MRID 4 4295773 Frey

, et.al ., 199 6 (Unpublished) / Acceptable Mean measured: 0, 46.3, 245 and 1221 mg ai/kg

- diet; 16 pairs (1 male and 1 female)

(a) Effect levels are expressed in terms of the chemical.: mg/kg

- bw is milligrams of the test material per kilogram of body weight; mg ai/kg

- bw is milligrams of Sulfosulfuron per kilogram of body weight; mg ai/kg

- diet is milligrams of Sulfosulfuron per kilog ram of diet.. (b) 5

- day exposure and 3

- day post

- exposure



### Table 2 Affect of Sulfosulfuron on Mammals

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects Source / Study Classification / Exposure Groups

SULFOSULFURON / 81

- 1 (870.1100)/ Acute Oral

– Rat ( Sprague

- Dawley ), young adult / Technical Sulfosulfuron ( 98. 9 % ) 14

- d LD 50 > 5,000 mg Sulfosulfuron/kg

- bw

(No mortality observed, soft or mucoid stools on Days 1

- 3 post dosing in limit dose) MRID 44295737 (Unpublished) Bonnette, 19 93 / Acceptable/ 0 ( corn oil ), 5000 mg/kg; 10 rats (5 females, 5 males ) per dose

SULFOSULFURON / 81

- 1 (870.1100) Acute Oral

– Rat ( Sprague

- Dawley ), 9

- 12 wk old / Formulation MON 37532 73.7 % Sulfosulfuron 14

- d LD 50 > 5,000 mg/kg

- bw

(No mortality or clinical signs of toxicity observed) MRID 44295738 (Unpublished) Blaszak, 1995 / Acceptable/ 0 , 5000 mg/kg; 10 rats (5 females, 5 males ) per dose

SULFOSULFURON / 81

- 1 (870.1100) Acute Oral

– Rat ( Sprague

- Dawley) / Formulation MON 37525 23.7 % Sulfosulfuron 14

- d LD 50 > 5,000 mg/kg

- bw

(No mortality observed; no clinical signs of toxicity observed in females; decreased activity, irregular gail and unformed stool observed in males during first 24 hr) MRID 45116102 (Unp ublished) Blaszak, 1999 / Acceptable/ 0 , 5000 mg/kg; 10 rats (5 females, 5 males ) per dose

SULFOSULFURON /81

- 2 (870.1200) Acute Dermal toxicity

– Rat ( Sprague

- Dawley), young adult Technical Sulfosulfuron ( 98. 9 % ) LD 50 > 5, 000 mg/kg MRID 44295739 (Unpublished) Bonnette, 19 93/ Acceptable/ 0, 5000 mg/kg

SULFOSULFURON /81

- 5 (850.2500) Primary Skin Irritation

– Rabbit (New Zealand) Technical Sulfosulfuron (98.9%) Non

- irritant MRID 44295743 (Unpublished) Bonnette, 19 93/ Acceptable/ 0.5 g/rabbit, 6 rab bits (2 males, 4 females)

### 78

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects Source / Study Classification / Exposure Groups

SULFOSULFURON /81

- 4 (870.2400) Primary Eye Irritation

– Rabbit (New Zealand) Technical Sulfosulfuron 98.9% Moderate Eye Irritant MRID 44295741 (Unpublished) Bonnette, 1 9 93 / Acceptable/ 0.084 g/eye, 6 rabbits (5 male, 1 female)

SULFOSULFURON /81

- 3 (870.1300) Acute Inhalation Toxicity

– Rat ( Sprague

Dawley) / Technical Sulfosulfuron ( >98. 5 % ) LD 50 > 3.0 mg/L

(4

- hour exposure, 14 d

- observation period; clinical signs observed during or immediately after exposure. Transient lack of weight gain in females. Enlarged liver in two males) MRID 44295745 (Unpublished) Bechtel, 19 94 / Acceptable/ 3.0 mg/L, 10 exposed (5 male, 5 female)

SULFOSULFURON/83

- 4 (870.3800) Reproduction 2

– generation

– rat (Sprague

Dawley)/ Technical Sulfosulfuron (98.4%) NOAEL = 312.1 mg/kg/day (5000 ppm) LOAEL = 1312 mg/kg/day (20,000 ppm)

(Decreased weight gain in parental and offspring, mortality in males, and increased incidence of urinary tract pathology) MRID 44295758 (Unpublished) Naylor & Thake, 1996/ 0, 50, 500, 5000, 20,000 ppm, 30 rats/sex/dose/generation

SULFOSULFURON/83

- 5 Chronic Toxicity

– Carcinogenicity rat/ Technical Sulf

osulfuron (98.4%) At 5,000 ppm urinary bladder transitional cell carcinoma and papilloma were observed in females MRID 44295759 (Unpublished) Naylor & Ruecker, 1997 / 0, 50, 500, 5000, & 20000 ppm

SULFOSULFURON/83

- 5 Chronic Toxicity

– Carcinogenicity mous e/ Technical Sulfosulfuron (98.4%) The LOEL is 3,000 ppm (393.6 mg/kg/day), based on gross and microscopic effects related to urinary calculus formation in the urinary bladder of males. MRID 44295755 (Unpublished) Naylor & Thake, 1997 / 0, 30, 700, 3000, and 7000 ppm



### Table 3 Affect of Sulfosulfuron on Terrestrial Invertebrates

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects Source / Study Classification / Exposure Groups

SULFOSULFURON /141

- 1 (850.3020) Honey bee Contact Test

– Honey bee (

Apis mellifera carnica L.), 1

- 7 d old/ Technical Sulfosulfuron (>98.5) 48

- h LD 50 > 25 μg a.i. /bee

(Mortality and clinical signs of toxicity in all treatment groups comparable to control) MRID 44295788 Palmer & Beavers ,19 94 / Acceptable / Nominal 0, 0 (acetone), 1.6, 3.1, 6.3, 12.5 and 25 μg a.i. /bee 50 bees/ concentration

SULFOSULFURON/ not applicable/Honey bee Oral Test

– Honey bee (

Apis mellifera carnica L.), 1

- 5 d old Technical Sulfosulfuron (>98.5) 48

- hr LC 50 > 29.6 μg ai/bee

(Mortality and clinical signs of toxicity in all treatment groups comparable to control) MRID 44295789 Palmer & Beavers

, 19 95 / Acceptable / Nominal 0, 1.85, 3.69, 7.39, 14.8, 29.6 μg a.i. /bee 60 bees/ concentration



### Table 4 Affect of Sulfosulfuron on Freshwater and Estuarine / Marine Fish

### 79

Chemical/Guideline No. / Study Type / Test Material Toxicological Effects Source / Study Classification / Exposure Groups

SULFOSULFURON /72

- 1 (850.1075) Acute Toxicity to Freshwater Fish

– Rainbow trout ( Oncorhynchuss mykiss ), ca. 79

- d old , static test /

Technical Sulfosulfuron (>98.5 % ) 96

- h LC 50 >93.6 mg a.i./L 96

- h NOAEC = 93.6 mg a.i./L

(no mortality or sublethal effects observed for test groups)

Classified as practically non

- toxic MRID 44295774 Graves & Swigert

, 19 94 (Unpublished) / Acceptable/ Mean measured 0 (<10) and 93.6 mg a.i./L

, 30 fish per treatment

SULFOSULFURON /72

- 1 (850.1075) Acute Toxicity to Freshwater Fish

– Bluegill Sunfish ( Lepomis macrochirus ), juvenile (22

- 29 mm), static test / Technical Sulfosulfuron (98. 5 % ) 96

- h LC 50 > 94.6 mg a.i./L 96

- h NOAEC = 94.6 mg a.i./L

(no mortality or sublethal effects observed for test groups)

Classified as practically non

- toxic MRID 44295775 Graves & Swigert

, 19 94 (Unpublished) / Acceptable/ Mean measured 0 (<10), and 94.6 mg a.i./L

, 30 fish per treatment

SULFOSULFURON /72

- 3 (850.1075) Acute Toxicity to Estuarine and Marine Organisms

– Sheepshead minnow ( Cyprinodan variegatus ), juvenile ( 23

- 29 mm ), static ) / Technical Sulfosulfuron (> 98. 5 % ) 96

- hr LC50 > 101 mg a.i./L 96

- hr NOAEC = 101 mg a.i./L

(no mortality or sublethal effects observed for test groups)

Classified as practically non

- toxic MRID 44309304 Graves & Swigert

, 19 95 (Unpublished) / Acceptable/ Mean measured 0 (<10), and 101 mg a.i./L

, 30 fish per treatment

SULFOSULFURON / 850.1400/ Fish early

- life stage toxicity test

– Rainbow trout ( Oncorhynchuss mykiss ), <24

- hr old, flow

- through
t est , 60

- d post hatch duration /

Technical Sulfosulfuron (98.5 % ) NOAEC = 100 mg a.i./L

(No effect on survival, growth, hatching or swim

- up at any treatment group compared to control) MRID 44295779 Graves, Mank & Swigert , 19 95 (Unpublished) / Acceptable/ Mean measured 0 (<2.5), 6.2, 13, 24, 49 and 100 mg a.i./L



### Table 5 Affect of Sulfosulfuron on Freshwater and Estuarine or Marine Invertebrates

Guideline No. / Study Type / Test Material Toxicological Effects Source / Study Classification / Exposure Groups

SULFOSULFURON /72

- 2 (850/1010) Acute Freshwater Invertebrate toxicity test

– Waterflea ( Daphnia magna ), <24

- h old, static test, /

Technical Sulfosulfuron (98. 5 % ) 48

- h EC 50 > 94.6 mg a.i./L 48

- h NOAEC = 94.6 mg a.i./L

(No immobility or sublethal effects observed for any treatment group)

Classified as practically non

- toxic MRID 44295776 Graves & Swigert, 19 94 (Unpublished) / Acceptable/ Mean measured 0 (<10) and 94.6 mg a.i./L

30 daphnia per test concentration

### 80

SULFOSULFURON /72

- 3 (850.1035) Acute Estuarine and Marine Organisms toxicity test

– Mysid shrimp ( Mysidopsis bahia ), juveniles, static test / Technical Sulfosulfuron (>98. 5 % ) 96

- h L C 50 >106 mg a.i./L 96

- h NOAEC = 106 mg a.i./L

(No mortality or sublethal effects observed for any treatment gr oup; exact age of organisms not reported)

Classified as moderately t oxic MRID 44295777 Graves & Swigert, 19 95 (Unpublished) / Supplemental/ Mean measured 0 (<10) and 106 mg a.i./L

30 mysid per test concentration

SULFOSULFURON /72

- 3 (850.1025) Acute Estuarine and Marine Organisms toxicity test

– Shell deposition ( Crassostrea virginica ), juveniles (34

- 44 mm), static test/ Technical Sulfosulfuron (>98. 5 % ) 96

- h I C 50 > 116 mg a.i./L 96

- h NOAEC = 116 mg a.i./L

(No effect on shell deposition at limit

conc entration; no sublethal effects observed)

Classified as moderately t oxic MRID 44295778 Graves & Swigert, 19 95 (Unpublished) / Acceptable/ Mean measured 0 (<10) and 116 mg a.i./L

30 oysters per test concentration

SULFOSULFURON /72

- 4 (850.1300) Chronic F reshwater Invertebrate toxicity test

– Waterflea ( Daphnia magna ), <24

- h old, static

- renewal test (3 times/weekly), 21

- d duration / Technical Sulfosulfuron (98.5 % ) NOAEC = 102 mg a.i./ L

(No effect on survival, growth, or reproduction at any treatment group compared to control) MRID 44295780 Graves, Mank & Swigert, 19 96 (Unpublished) / Acceptable/ Mean measured 0 (<2.5), 6.5, 13, 27, 53 and 102 mg a.i./L

10 daphnia per test concentration



### Table 6 Affect of Sulfosulfuro n on Aquatic Plants

Chemical/Guideline No. / Study Type / Test Material EC 50 /I C 50 Endpoint Affected NOAEC Endpoint Affected Source / Study Classification / Exposure Groups
Nonvascular

SULFOSULFURON /122

- 2 (Tier I) (850.5400) Algal toxicity test marine diatom Skeletonema costatum , static Technical Sulfosulfuron (> 98.5% ) 120

- hr EC 50 > 103 mg a.i. (total)/L

(particulates observed in test solution; no effort to remove prior to analysis reported) 120

- hr NOAEC = 103 mg a.i. (total)/L

(based on cell density, yield, growth rate) MRID 4 4295781 Thompson & Swigert, 1996 / Supplemental/

Mean measured 0 (<7.36) and 103 mg a.i. (total)/L

SULFOSULFURON /122

- 2 (Tier I) (850.5400) Algal toxicity test freshwater diatom Navicula pelliculosa , static / Technical Sulfosulfuron (> 98.5% ) 120

- hr I C 50 > 87 mg a.i. (total)/L

(particulates observed in test solution; no effort to remove prior to analysis reported) 120

- hr NOAEC = 87 mg a.i. (total)/L

(based on cell density, yield, growth rate) MRID 4 4295782 Thompson & Swigert, 1996 / Supplemental/

Mean measured 0 (<7.36) and 87 mg a.i. (total)/L

### 81

Chemical/Guideline No. / Study Type / Test Material EC 50 /I C 50 Endpoint Affected NOAEC Endpoint Affected Source / Study Classification / Exposure Groups

SULFOSULFURON /122

- 3 (850.5400) (Tier II) Algal toxicity test green algae Selenastrum capricornutum

, static/ Technical Sulfosulfuron (> 98.5% ) 120

- hr I C 50 = 0.310 mg a.i./L (310 μg a.i/L) (based on area under curve)

(only 2 highest concentrations analyzed; NOAEC and EC50 value fall within range of unmeasured test concentrations) 120

- hr NOAEC = 0.0926 mg a.i./L (92.6μg a.i/L)

(based on area under curve) MRID 4 4295785 Thom pson & Swigert, 1995 / Supplemental/

Nominal 46.3, 92.6, 185, 369 μg a.i./L; mean measured 542 and 1251 μg a.i./L

SULFOSULFURON /122

- 3 (850.5400) (Tier II) Algal toxicity test blue

- green algae Anabaena flos

- aquae , static / Technical Sulfosulfuron (> 98.5% ) 120

- hr I C 50 = 0.560 mg a.i./L (560 μg a.i/L) (based on area under curve)

(2 lowest test concentrations not analysted; NOAEC and EC50 value fall within range of unmeasured test concentrations) 120

- hr I C 05 = 0.038 mg a.i./L (38 μg a.i/L)

(based on area under curve) MRID 4 4295786 Thompson & Swigert, 1996 / Supplemental/

Nominal 0.31, 0.63 mg a.i./L; mean measured 1.3, 2.5, 5.3 mg a.i./L

Vascular

SULFOSULFURON /12 3

- 2 (850.4400) (Tier II) T oxicity
test duckweed Lemna gibba freshwater , static Technical Sulfosulfuron (> 98.5% ) 14

- d EC 50 ≈ 0.985 μg a.i./L ( based on frond count) (test solutions not analyzed) 14

- d NOAEC =0.49 μg a.i./L

( based on frond count) MRID 4 4295787 Thompson & Swigert, 1996 / Supplemental/

Nominal 0.031, 0.062, 0.13, 0.25, 0.49 and 0.985 μg a.i./L

### 82

Table 7 Affect of Technical Sulfuron (98.4% ) on Terrestrial Plant Vegetative Vigor *

Species EC 25 (lbs ai/A) 1
Most Sensitive Endpoint Affected NOAEC (lbs ai/A) 1 Endpoint Affected

Dicot

- Cabbage 0.0013

– Dry Weight 0.005

– Dry Weight

Dicot

- Cucumber 0.0246

– Dry Weight 0.0078

– Dry Weight

Dicot

- Lettuce 0.0043

– Dry Weight 0.002

– Dry Weight

Dicot

- Radish 0.0000 84

– Dry Weight 0.00003 1

– Dry Weight

Dicot

- Soybean 0.00063

– Dry Weight 0.00005

– Dry Weight (EC 05 )

Dicot

- Tomato 0.051

– Dry Weight 0.032

– Dry Weight

Monocot

- Corn 0.0074

– Dry Weight 0.0029

– Dry Weight (EC05)

Monocot

- Oat 0.0054

– Dry Weight 0.0039

– Dry Weight

Monocot

- Onion 0.0041

– Dry Weight 0.0039

– Dry Weight

Monocot

- Rye 0.00 34

– Dry Weight 0.0020

– Dry Weight

* Source: Results are MRID # 4 4295784 Chetram & Cone 1995 (Unpublished); Stu dy classification: Supplemental Bold values are the most sensitive endpoints for either the monocot or dicot



### Table 8 Affect of Technical Sulfuron (98.4% ) on Terrestrial Plant Seedling Emergence*

Species EC 25 (lbs ai/A) 1
Most Sensitive Endpoint Affected NOAEC (lbs ai/A) 1 Endpoint Affected

Dicot

- Cabbage 0.0014

– Dry Weight 0.0010

– Dry Weight

Dicot

- Cucumber 0.0012

– Dry Weight 0.0010

– Height

Dicot

- Lettuce 0.0027

– Dry Weight 0.0010

– Height

Dicot

- Radish 0.000 7

– Dry Weight 0.00 1

– Dry Weight 0.000091

– Dry Weight (EC 05 )

Dicot

- Soybean 0.006 6

– Dry Weight 0.00 20

– Height

Dicot

- Tomato 0.0105

– Dry Weight 0.0020

– Dry Weight

Monocot

- Corn 0.0053

– Dry Weight 0.001

– Height

Monocot

- Oat 0.0138

– Dry Weight 0.0079

– Dry Weight

Monocot

- Onion 0.00 077

– Dry Weight 0.000 1

– Dry Weight (EC 05 )

Monocot

- Rye 0.0078

– Dry Weight 0.0020

– Dry Weight

* Source: Results are MRID # 4 4295783 Chetram & Cone 1997 (Unpublished); Stu dy classification: Supplemental Bold values are the most sensitive endpoints for either the monocot or dicot

### 83

Appendix D . GENEEC2 Output

RUN No. 1 FOR Sulfosulfuron ON NativeGras * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE NO

- SPRAY INCORP ONE(MULT) INTERVAL Kd (PPM ) (%DRIFT) ZONE(FT) (IN)

--- ----------------------------------------------------------------- .125( .125) 1 1 .2 1627.0 AERL_B( 13.0) .0 .0

FIELD AND STANDARD POND HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (POND) (POND

- EFF) (POND) (POND)

------------------------------------- ------------------------------- 243.89 2 N/A 2.47

- 306.28 45.90 39.92

GENERIC EECs (IN MICROGRAMS/LITER (PPB)) Version 2.0 Aug 1, 2001

-------------------------------------------------------------------- PEAK MAX 4 DAY MAX 21 DAY MAX 60 DAY MAX 90 DAY
GEEC AVG GEEC AVG GEEC AVG GEEC AVG GEEC

-------------------------------------------------------------------- 7.33 7.23 6.67 5.60 4.93

### 84

Appendix E . T

- REX Output

### 85

### 86

### 87

Appendix F . SIP Output

### 88

Appendix G . STIR Input and Output



# Welcome to the EFED Screening Tool for Inhalation Risk This tool is designed to provide the risk assessor with a rapid method for determining the potential significance of the inhalation exposure route to birds and mammals in a risk assessment.



# Input

Application and Chemical Information
Enter Chemical Name sulfosulfuron Enter Chemical Use non

- ag and ag Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) air Enter Chemical Molecular Weight (g/mole) 470.79 Enter Chemical Vapor Pressure (mmHg) 2.22E

- 10 Enter Application Rate (lb a.i./acre) 0.125

Toxicity Properties

Bird Enter Lowest Bird Oral LD 50 (mg/kg bw) 2250 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 0.178 Mammal
Enter Lowest Rat Oral LD 50 (mg/kg bw) 5000
Enter Lowest Rat Inhalation LC 50 (mg/L) 3 Duration of Rat Inhalation Study (hrs) 4 Enter Rat Weight (kg) 0.35


# Output Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 5.62E

- 06 Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 7.07E

- 07 Adjusted Inhalation LD 50 7.53E+00 Ratio of Vapor Dose to Adjusted Inhalation LD 50 9.39E

- 08 Exposure not Likely Significant
Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 1.20E

- 02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 1.60E

- 03 Exposure not Likely Significant



### Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 5.62E

- 06

### 89

Maximum 1

- hour Vapor Inhalation Dose (mg/kg) 8.89E

- 07 Adjusted Inhalation LD 50 1.79E+02 Ratio of Vapor Dose to Adjusted Inhalation LD 50 4.98E

- 09 Exposure not Likely Significant
Maximum Post

- treatment Spray Inhalation Dose (mg/kg) 1.51E

- 02 Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD 50 8.45E

- 05 Exposure not Likely Significant