### 1 UNITED STATES ENVIRONMEN TAL PROTECTION AGENCY WASHINGTON, D.C. 20460

OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION



### PC Code: 129009
DP Barcode: 384624 Date: 10/27/11

MEMORANDUM

SUBJECT: Tier I Estimated Drinking Water Concen trations of Rimsulfuron, for the Use in the Human Health Risk Assessment: New Use Request for the Use of Rimsulfuron on Caneberry 13-07A and Bushberry Subgroup 13-07B.

TO: Debra Rate, Acting Team Lead Section 18 and 24C Risk Integration, Minor Use a nd Emergency Response Branch

Mindy Ondish, Risk Manager Reviewer Kable Davis, Risk Manager Herbicide Branch Registration Division (7505P)

AND: Elizabeth Holman, Lead Assessor Christina Swartz, Chief Registration Action Branch II Health Effects Division (7509P)

FROM: Michael Barrett, Senior Chemist Environmental Risk Branch 5 Environmental Fate a nd Effects Division (7507P)

THROUGH: Mah Shamim, Ph.D., Branch Chief Environmental Risk Branch 5 Environmental Fate a nd Effects Division (7507P)

This memorandum updates the Tier 1 Estimated Drinking Waters Concentrations (EDWCs) for surface and ground waters for rimsulfuron, a pyr imidinyl sulfonylurea herbicide (CAS name: N

- [[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-(e thylsulfonyl)-2-pyridinesulfonamide; CAS No. 122931-48-0), calculated using the Tier 1 aqua tic models FIRST and SCI-GROW, for use in the human health risk assessment. This update is based upon a Section 3 New Use (IR4) request

### 2 for the use of Rimsulfuron [Matrix SG (w ater soluble granule) (Reg. No. 352-768)] on Caneberry Subgroup 13-07A (cranberry) and Bushbe rry Subgroup 13-07B (blu eberry). Matrix SG contains 25% active ingredient by weight in the formulatio n. The proposed application rates are up to a total of 0.0625 lb a.i. /A per season, which is consistent with previously registered uses. Two applications may be made when usin g a banded treatment with a minimum of a 30 day interval, however, a total of 0.0625 lb a.i./A still should not be exceeded on a per year basis.

In general, applications can be made by both aerial ground methods and chemigation, but not via aerial application methods.

The previous Tier 1 modeling covers these new uses (see attached copies of reviews under DP Barcodes D358869, D358875 (assessment dated 7/24/ 2009) and D 334221 (2/6/2007). This is because there is no difference in the use pattern for these new uses that would modify the inputs for the Tier 1 modeling to the extent that the highes t previously calculate d estimated drinking water concentrations would change. Should there be the need, additional levels of refinements are possible with a hi gher tier assessment.

For rimsulfuron, the surface water acute drinking water exposure valu e is still estimated to be 5.596 ppb, and the cancer/ chronic value is still 0.120 ppb. The groundwater screening concentration is still 0.016 ppb of rimsulfuron, which is suitable for acute and chronic exposure (see Table 1 in the attached assessment from 7/24/2009).

### 3 

## Electronic Copy of Previous Drin king Waters Analysis (7/24/2009 Assessment)

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PEST ICIDES AND TOXIC SUBSTANCES

PC Code 129009 DP Barcode D358869, D358875 Date July 24, 2009



### MEMORANDUM

SUBJECT: Tier I Estimated Drinking Wate r Concentrations of Rimsulfuron, for the Use in the Human Health Risk Assessment: New Use Proposals for the Chemical on DUPONTTM OPTIMUM® GAT® Corn and Soybeans

TO: Vickie Walters, Risk Manager Reviewer James Tompkins, Product Manager 25 Daniel Kenny, Chief Herbicide Branch Registration Division (7505P)

AND: Douglas Dotson Cristina Swartz, Chief Registration Action Branch II Health Effects Division (7509P)

FROM: José L. Meléndez, Chemist Environmental Risk Branch V Environmental Fate a nd Effects Division (7507P)

APPROVED BY: Mah T. Shamim, Branch Chief Environmental Risk Branch V Environmental Fate and Effects Division (7507P)

This memorandum presents the Tier 1 Es timated Drinking Waters Concentrations

### 4 (EDWCs) for surface and ground waters for rimsulfuron, a pyrimidinyl sulfonylurea herbicide (CAS name: N -[[(4,6-dimethoxy-2-pyri midinyl)amino]carbonyl]-3- (ethylsulfonyl)-2-pyridinesul fonamide; CAS No. 122931-48-0), ca lculated using the Tier 1 aquatic models FIRST and SCI-GROW, for us e in the human health risk assessment. This Drinking Waters Assessment (DWA) is largely based on a previous DWA, dated February 6, 2007 (electronic copy is provided below). The EDWCs were calculated based on the maximum application rate of 0.0625 lb a.i./A/season (for citrus, pome and stone fruits, ground broadcast app lication, wetted in). For rimsulfuron, the surface waters acute value is 5.596 ppb, and the cancer/ chr onic value is 0.120 ppb. The groundwater screening concentration is 0.016 ppb of rimsulfuron, which is suitable for acute and chronic (refer to Table 1). EFED stresses the fact that this is a Tier 1 screening-level analysis and should there be the need, addi tional levels of refinements are possible.

Currently, rimsulfuron is used on a numb er of crops, including corn (maximum application rate for corn, 0.03125 lb a.i./A ). EFED evaluated the new uses for rimsulfuron on DUPONTTM OPTIMUM® GAT® herb icide tolerant corn and soybean for pre-emergence and post-emergence control of ce rtain annual grass a nd broadleaf weeds. The product name is RESOLVETM SG Herbicid e (water soluble gran ule, containing 25% a.i.). It was noted that aerial applicati ons are allowed for these uses and the maximum application rate is 0.0625 lb a. i./A for both crops (same than the previously assessed for citrus, pome and stone fruits). It was evalua ted if the new scenarios posed more exposure than previously assessed. The results of a FIRST run showed lower EDWCs than the previously assessed scen arios (refer to Appendix A for the table of input parameters used, and a copy of the output file from FIRST). Th erefore, EFED relied on the results of the previous DWA for this assessment. It appears that, because the pesticide is not wetted in and a specific PCA was used (for corn and soybeans, 0.83), the results were lower for the new scenarios.

None of rimsulfuron’s transformation products were included in this assessment. Based on a HED’s March 29, 1994 memorandum, it was concluded that, “None of rimsulfuron’s metabolites warrant inclusion in tolerance regul ation or separate regulation or inclusion in the dietary risk assessment” (refer to Attachment 1 of the attached 2/7/2007 DWA Assessment). Rimsulfuron shows significant levels of various transformation products that may persist in the environment and may contaminate surface or ground waters.

For information related to the environmental fate characterist ics of rimsulfuron, mode of action, uncertainties, etc., pleas e, refer to the previous DW A, provided in Appendix B. For any questions related to this do cument, please, contact us in EFED.

Table 1. Maximum Tier I EDWCs for drinkin g water assessment based on g round

a pp lication of rimsulfuron*

Use/Rate Modeled: Fruit trees applied once, by ground spra yers, at a rate of 0.0625 lbs. a.i./A

Chemica l Maximum Sur f

ace water EDWC ( pp b) Maximum Ground water Acute/Chronic EDWC ( pp b) Acute Valu e Chronic/Cancer Valu e Rimsulfuron Parent 5.596 0.120 0.016

### 5 * Degradates are not included as recommended by HED Metabolism Committee. Please, refer to 

### attached 2/7/2007 DWA Assessment for further details.

### 6 

## Appendix A. FIRST Supplementary R un Inputs Parameter Table and Output File

Table A1. FIRST input parameters for modeling drinki ng water EDWCs

Input Parameter Value* Reference

Application Rate (lb a.i./Acre) 0.0625 (One Application) Maximum label rate/Minimum application intervals (Product Label) Application Intervals (days) Does not apply, 1 applic.

Percent Crop Area 0.83 Corn and soybeans

Partition Coefficient “K OC ” (L/Kg) 19 Lowest non-sand value (MRID 413563-36)

Aerobic Soil Metabolism Half-life (days) 64 Determined by multiplying the available half-life by 3 to account for the uncertainty associated with using a single value (21.3x3; MRID 413563-34)

Wetted In? No
Product Label Depth of Incorporation (inches) 0 Method of Application Aerial
Solubility in Water (ppm) 7.3 MRIDs: 419316-02 and 413563-01.
Aerobic Aquatic Metabolism Half-life (days) The experiment was exposed to artificial light source thus the value was not used and hydrolysis half-live was entered.
Hydrolysis Half-life @ pH 7 (days) 7.2 Average value at pH 7 (MRID 413563-33)
Direct Aqueous Photolysis Halflife(days) Stable Half-lives in dark<irradiated samples (MRID 419316-08)
* Fate data values are as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides; Version II, February 28, 2002.

### 7 

## Appendix A. FIRST Supplementary R un Inputs Parameter Table and Output File (cont.)

FIRST Output Run:

RUN No. 1 FOR Rimsulfuron ON Soy+Corn * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- 0.063( 0.062) 1 1 19.0 7.3 AERIAL(16.0) 83.0 0.0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 64.00 2 0.00 0.00- 0.00 7.20 7.20

**UNTREATED WATER CONC** (MICROGRAMS/LITER ( **PPB** )) Ver 1.1.1 MAR 26, 2008

-------------------------------------------------------------------- **PEAK** DAY ( **ACUTE** ) **ANNUAL AVERAGE** ( **CHRONIC** )
CONCENTRATION CONCENTRATION

-------------------------------------------------------------------- **5.138 0.111**

### 8 

## Electronic Copy of Previous Dr inking Waters Analysis (2/6/2007 Assessment) UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460

OFFICE OF PREVENTION, PESTICIDES AND TOXIC SUBSTANCES

PC Code No.: 129009 DP Barcode: D 334221 Date: February 6, 2007 

### MEMORANDUM

SUBJECT: Estimated Drinking Water Con centrations of Parent Rimsulfuron for the Use in Human Health Risk Assessment.

TO: James Tompkins, Risk Manager 25 Vickie Walters, Risk Manager Reviewer John Redden, Team Leader, ARIA Registration Division (7505P)

AND: Christina Swartz, Branch Chief RAB2, HED (7509P)

FROM: M. A. Ruhman, Agronomist, Environmental Fate Reviewer Environmental Fate a nd Effects Division (7507P)

THROUGH: Mah T. Shamim, Ph.D., Chief Environmental Risk Branch V Environmental Fate a nd Effects Division (7507P)

I. EXECUTIVE SUMMARY This memo presents the Estimated Drinking Water Concentrations (EDWCs) for parent Rimsulfuron for use in an FQPA human hea lth risk assessment. It is noted that significant quantities of some of rimsulfuron transforma tion products/degradates may persist in the environment and may contam inate surface/ground water. None of these transformation products/degradates are include d in this risk assessment based on HED Metabolism Committee Memorandum dated March 29, 1994. The Committee concluded that “None of the rimsulfuron metabolites warr ant inclusion in the tolerance regulation or separate regulation or inclusion in the dietary risk assessment ” (Attachment No. 1 ).

### 9 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.) Rimsulfuron is selective/systemic pyrimidinyl sulfonylurea herbicide. Rimsulfuron is a member of the sulfonylurea family 1 

### with a mode of action that inhibit acetolactate synthase ALS (ALS is also known as acetohydroxyacid synthase AHAS) (HRAC Group B) 2 

### . ALS or AHAS is a key enzyme in biosynthesi s of certain amino acids in plants. This herbicide is currently regist ered as pre/post emergence w eeds control in field corn, potatoes, potatoes grown for seed, and field grown tomatoes. The re gistrant is seeking new section 3 registration for new use on grap es, stone Fruit, tree nuts, pistachios, pome fruit, and citrus fruit. These proposed new us es for rimsulfuron may cause the chemical to reach surface and to a lesser extent groundwater under some conditions.

The screening level surface water and ground water estimates for rimsulfuron parent are calculated using tier 1 models of FIRST (version 1.0) and SCI-GROW (version 2.3) , respectively. The estimates are presented in Table 1 for surface/ground water

.

Table 1. Maximum Tier I EDWCs for drinking water assessment based on ground application of rimsulfuron*
Full chemical name: N -[[(4,6-dimethoxy-2- p yrimidinyl)amino]carbonyl]-3-(ethylsulfonyl)-2- p yridine sulfonamide CAS No.: 122931-48-0 PC Code: 129009 Use/Rate Modeled: Fruit trees applied once, by ground spra yers, at a rate of 0.0625 lbs. a.i./A

Chemica l Maximum Sur f

ace water EDWC ( pp b) Maximum Ground water Acute/Chronic EDWC ( pp b) Acute Valu e Chronic/Cancer Valu e Rimsulfuron Parent 5.596 0.120 0.016 * Degradates are not included as recommended by HED Metabolism Committee.



### The above stated values for parent rims ulfuron represent upper-bound estimates of concentrations that might be found in surface water and groundwater due to the propose new use of the chemical on grapes, stone Frui t, tree nuts, pistachi os, pome fruit, and citrus fruit using one application at the ma ximum yearly rate (worst case scenario). EFED emphasizes that th is is a tier 1 screening-level an alysis, and should there be a need, by HED, additional refinements can be made. It is noted that this assessment supersedes earlier assessment entitled “Preliminary Drinking Water Exposure Assessment” Dated 02/25, 1998. In this referenced assessment ol der models and parameter guidance were used.

Only one aerobic soil study was submitted and in order to be protective it was necessary to multiply this half-life by 3 before use in modeling. The geographic extent of use warrant the submission of new aerobic soil studies using so ils representing new/current use areas. Uncertainties in representati on of the default half-life may result in conservative EDWCs.

1 URL: http://www.alanwood.net/pesticides/

2 URL: http://www.plantprotection.org/hrac/Bindex.cfm?doc=moa2002.htm

### 10 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.) II. PROBLEM FORMULATION This is a Tier I drinking water assessment that uses modeling (no monitoring data is available) to estimate the surface and ground water concentrations of pesticides in drinking water source water (pre-treatment) re sulting from pesticide use on sites that are highly vulnerable. This initial tier screen s out chemicals with low potential risk and provides estimated exposure concentrations fo r human health dietary risk assessment.

III. ANALYSIS (1) Use Characterization Rimsulfuron herbicide formulation (DPX-E 9636 FNV Dry Flowable) contains 25.0% of the active ingredient is proposed to be applie d, by injection through sprinkler irrigation or by ground equipment only. For ground application, the herbicide is applied as a uniform broadcast to orchard or vineyard floor or as a uniform band at the base of the trunk or vine. The best results can be obtained fr om this systematic pre/early post emergence herbicide by applying to cool soils and by moisture activation within 2-3 weeks of application. Activation can be achieved by rain fall or overhead irrigation of a minimum of 1⁄2 to 1 inch. The herbicide is recomme nded for use on vigor an d healthy trees that have been established for two full growing seasons. One single application of 4 ounces of product in 10 gallons of <4 or >8 pH buffered water/acre/year is recommended for either the broadcast or the band treatmen ts. The chemical may be applied twice (maximum 4 ounces) on 50% or less band along th e base of the trees with a minimum of 30-day intervals. It is claimed to control su sceptible weeds over a period of 60 to 90 days.

The maximum label rates for the proposed new uses are presented in Table 2

.

Table 2. Rimsulfuron use patterns (Maximum rates/number and minimum intervals are included).

Crop Spray Type Target Application: Maximum Rate/Number and Minimum Interval Rate (lb a.i./Acre) Number Interval (days)

Citrus/Pome/S tone Fruits, Tree nuts, and Grapes Ground Broadcast injection through sprinkler Whole Soil Surface 0.0625 1

Not applicable Ground Broadcast

Banded A soil surface band through base of
trees 0.0625 1

0.03125 * 2 30 * Assuming that each application= ha lf of the yearly application



### (2) Environmental Fate/Transport Characterization

Table 1 (Attachment No. 2 ) contains a detailed summary of the physical/chemical and environmental fate/transport properties of rimsulfuron. Hereunder, is a summary of

### 11 various parameters that relates to its predicte d behavior in various compartments of the



## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

environment and possible contamination of surface/ground water.

(a) Environmental Persistence/Mobility Rimsulfuron has a low vapor pressure (1.447 x10 -11 

### atms. at 25 o 

### C) and is highly soluble in water (solubility 7.3 ppm at 20 o 

### C 3 

### ). Based on submitted environmental fate studies, the chemical is short lived in aqueous sy stems (mainly affected by hydrolysis with hydrolysis half-lives ranging from 5-7 days in acidic/neutral conditions and <1day in alkaline conditions). Also the chemical is short-lived in aerobic/anaerobic soil systems (t 1/2 

### = 19-21 days determined for only one soil, s horter half-lives were determined under field conditions: t 1/2 

### = 5 to 18 days). Rimsulfuron a ppears not to be affected by aqueous/on soil photolysis.

Adsorption/desorption were studied using four soils with varied texture and organic matter contents (clay content= 4-30% a nd organic carbon content= 0.6-2.5%). The observed partitioning coefficient K oc 

### ranged from 19-74 L Kg -1 

### suggesting that rimsulfuron may be highly mobile and vulnerabl e to run-off and leaching. Therefore, the chemical may reach surface and ground water resources.

(b) Environmental Metabolites and their Persistence/Mobility Rimsulfuron is expected to transform/de grade into a number of transformation/ degradation products under differe nt environmental conditions ( Figure 1, Attachment No. 3 ). The three major degradates for rimsulfur on result from contraction or cleavage or the sulfonurea-bridge (IN-70941 and IN-70942 from contraction while IN-J9260 from cleavage). In contrast, the minor degrad ates are cleavage degradates (IN-J9260 in systems other than aerobic soil, IN-J290 a nd IN-T5831). A summary of the degradation profiles in various laborator y systems is included in Table 3

.

Table 3. Transformation/degradation profiles of rimsulfuron in various systems.

Degradate Name Max Degradate Concentration in % of app lied and (Time in Days to Max Co ncentration; Does it Decline Y/N)
Hydrolysis @ pH7 Aerobic Soil Anaerobic Soil Other Studies

IN-70941 17% (3 days; Y to 1%) 55% (10 days; Y to 30%) 32% (10 days; Y to 6%) H 2 OPhotolysis: Similar to hydrolysiswith reduction in transformation of IN70941 into IN-70942 and/or increase in the degradation of IN-70942. Plus enhanced formation of IN-J920 and IN-E9260 Aerobic Aquatic Data: May not represent the natural environment as the system was exposed to light TFD (Terrestrial Field Dissipation) Data: None Identified possibly due to IN-70942 84% (30 days; N) 30% (360 days; N) 56% (360 days; N)

IN-E9290 10% (30 days; N) 19% (30 days; Y to 16%) 23% (360 days; N)

IN-J290 7% (14 days; Y to 6%) 3% (30 days; Y to 1%) 8% (28 days; Y to 6%)

3 It was not clear if the reported solubility was 7.3 or 7,300 ppm; therefore the solubility of 7.3 ppm was assumed to be the correct solubility as values reported elsewhere were near the 7.3 value (for example, The solubility was reported to be 10 ppm in the EU database).

### 12 Degradate Name Max Degradate Concentration in % of app lied and (Time in Days to Max Co ncentration; Does it Decline Y/N)
Hydrolysis @ pH7 Aerobic Soil Anaerobic Soil Other Studies inappropriate LOD/LOQ (limits of detection/quantification)


## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

Degradate Name Max Degradate Concentration in % of app lied and (Time in Days to Max Co ncentration; Does it Decline Y/N)
Hydrolysis @ pH7 Aerobic Soil Anaerobic Soil Other Studies

IN-T5831 None Only Minor @ pH 5 1% (270 days, Y to <1%) 1% (360 days, N)



### Mobility of the transformation products/degradates were checked by TLC (thin layer chromatography) and results indicate high mobility to IN-E9260 and high to medium mobility for IN-70941, IN-70942 and IN-J290. Sol ubility was reported for only IN-70941 and IN-70942 and was 0.7 ppm for the first and 0.2 ppm for the second. Considering quantities formed and relative persistent, the three rimsulfuron degradates are expected to reach both surface and ground water at varied concentr ations. The timeline for this event is expected to be as follows: IN- 79041 at the short to medium-term (because it transforms into IN-70942), IN -70942/IN-E9290/In-J290 at the medium to long-term. Finally, IN-70942 is expected to be the terminal and pers istent degradate.

(3) Drinking Water Exposure Modeling

(a) Models Surface and ground water EECs for drinking water (EDWCs) for rimsulfuron were obtained by modeling using tier 1 FIRST (version 1.0) and SCIGROW (version 2.3) simulated models, respectively.

FIRST (FQPA Index Reservoir Screening T ool) is a meta-model of PRZM and EXAMS used as a screening tool to estimate pesticide concentratio ns found in surface water used as drinking water. FIRST was developed by making multiple runs of PRZM using varying sorption coefficients and determin ing the concentration in the EXAMS index reservoir scenario after a two-inch single stor m event. (The Index Reservoir is a standard water body used by the Office of Pesticide Programs to a ssess drinking water exposure (Office of Pesticide Programs, 2002). It is ba sed on a real reservoir (albeit not currently in active use as a drinking water supply), Ship man City Lake in Illinois, that is known to be vulnerable to pesticide contamination.) The single runoff event moves a maximum of 8% of the applied pesticide into the reservoir (FIRST Users Manual; 08/01/2001).

SCIGROW (Screening Concentrat ion in Ground Water) is a re gression model used as a screening tool to estimate pesticide con centrations found in ground water used as drinking water. SCIGROW was developed by fitting a linear model to groundwater

### 13 concentrations with the Relative Index of L eaching Potential (RILP) as the independent variable. Groundwater concen trations were taken fr om 90-day average high concentrations from Prospective Ground Wate r studies; the RILP is a function of aerobic soil metabolism and the soil-water parti tion coefficient. The output of SCIGROW represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, which is re presentative of the ground water most vulnerable to pesticide contamination likely to serve as a drinking water source ( SCIGROW: Users



## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

Manual (11/01/2001, revised 08/23/2002).

If drinking water levels of concern are exc eeded for Tier I surface water EDWCs, Tier II modeling will be able to refine these EDWCs by including vola tility, Henry’s Law, diffusion in air, and enthalpy considerati ons. Since SCIGROW is a regression model developed from actual pesticide data with a ra nge of volatilities, systematic conclusions cannot be drawn about over or underestima tion of groundwater EDWCs at Tier I.

(b) Modeling Approach and Input Parameters Input values used in FIRST modeling we re based on the label and fate/transport parameters and are summarized in Table 4

.

Table 4. FIRST input parameters for modeling drinking water EDWCs.

Input Parameter Value* Reference

Application Rate (lb a.i./Acre) 0.0625 (One Application) 0.0313 (Two Application) Maximum label rate/Minimum application intervals (Product Label) Application Intervals (days) 30

Percent Crop Area 0.87 Fruit trees

Partition Coefficient “K oc ” (L Kg -1 ) 19 Lowest non-sand value (MRID 413563-36)

Aerobic Soil Metabolism Half-life (days) 64 One half-life x 3 (21.3x3; MRID 413563- 34)

Wetted In? Yes
Product Label Depth of Incorporation (inches) 0 Method of Application Ground**

Solubility in Water (ppm) 7.3 MRIDs: 419316-02 and 413563-01; Using water solubility of 7,300 ppm have not affected the results.
Aerobic Aquatic Metabolism Halflife (days) The experiment was exposed to artificial light source thus the value was not used and hydrolysis half-live was entered.
Hydrolysis Half-life @ pH 7 (days) 7.2 Average value at pH 7 (MRID 413563-33)
Direct Aqueous Photolysis Halflife(days) Stable Half-lives in dark<irradiated samples (MRID 419316-08) * Fate data values are as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate

### 14 and Transport of Pesticides; Version II February 28, 2002. ** The label permits application through the Sprinkler Irrigation Systems (reason for choosing ground application is stated in the text)



### Modeling was simulated for applying the pestic ide once or twice as stated in the label. The results, for two applications, were lower compared to one application possibly due to degradation within the 30-day in terval between applications ( Table 5 ). For reference, sample runs are included in Attachment No. 4.



## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

Table 5. Modeled EDWCs of rimsulfuron in surface water. Application Procedure/Time Line Peak Da y (Acute; ppb) Annual Average (Chronic; ppb)
Once (applied only one time) 5.596 0.120
Twice (divided in half with 30-day interval) 4.786 0.103



### Although higher drift might be associated w ith sprinkler irrigati on, ground application was chosen for the simulation as the EDWCs were more conservative. This was confirmed by running the model with drift value of up to 16 % (aerial application) which gave lower EDWCs (i.e. less conservative values). The reason for such results is associated with the how concentrations are ca lculated by the model combined by the fact that this chemical has low affinity to soil particles resulting in higher importance of runoff than drift. As shown in Table 6 , the model calculates lower amounts of the pesticide pool available for run-off in aerial compared to ground spray (amount of 2.114 lbs compared to 2.028 lbs). Although, the model calcu lates higher amount of drift for aerial compared to ground (0.130 lbs for aerial compared to 0.052 lbs for ground), these amounts are only 3-6% of the pesticide run-off pool.

Table 6. Rimsulfuron: Amount of run-off and drift pools as calculated by FIRST.

Pesticide Pools Ground spray Aerial spray. Bases for the calculation Run-off 2.114 lbs (427 x 0.0625*x 0.08 x 0.99) 2.028 lbs (427 x 0.0625*x 0.08 x 0.95) 8% of the total mass of pesticide applied to 427 acres watershed with application efficiency of 99% for ground and 95% for aerial. Drift 0.052 lbs (13 x 0.0625* x 0.064) 0.130 lbs (13 x 0.0625* x 0.16) Fraction of the rate of the amount applied to 13 acres water body with drift values of 6.4% for ground and 16% for aerial. * The value of 0.0625 = application rate which is equal to 0. 0625 lb a.i./Acre.



### Input values used in SCI-G ROW modeling were based on the label and fate/transport parameters summarized in Table7.

Table 7 . SCI-GROW input parameters for mode ling drinking water from ground water (EDWCs).

Input Parameter Value Reference

### 15 Input Parameter Value Reference

Application Rate (lb a.i./Acre) 0.0625 Maximum Yearly Application rate (Product Label) Maximum Number of Applications/Year 1

Partition Coefficient “K oc ” (L Kg -1 ) 55 Median of 4 values (<3 fold variations in K oc s (MRID 413563-36)

Aerobic Soil Metabolism Half-life (days) 21.3 One half-life (MRID 413563-34)



### A summary of the results is included in Table 8 . For reference, a sample run is included



## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

in Attachment No. 4.

Table 8. Summary of outputs from SCI-GROW for rimsulfuron.
Application Procedure/Time Line Acute and Chronic Values (ppb)
Once (applied only one time) 0.0158
Twice (divided in half with 30-day interval) 0.0158



### IV. MONITORING DATA Although this pesticide is curr ently registered for use, no monitoring data was found or submitted.

V. DRINKING WATER TREATMENT No data were submitted for drinking water treatment effects. However, water treatment may include water softening which generally increase the pH. This pesticide is expected to hydrolyze at much faster rates in alka line systems (half-life of 4-11 hours at pH 9 compared to 5-7 days at pHs 5 and 7). Ther efore, enhanced degradation is expected as result of water treatment raising the pot ential for lower EDWCs in treated water compared to the modeled raw water.

VI. CONCLUSIONS For surface water, only one aerobic soil half- life was available, EDWCs were calculated based on a default half-life va lue that is three times longer. Therefore, EDWCs could therefore be conservative. The registrant may submit additional aerobic soil studies to represent the range of texture and organic matter for so ils in the expanded use areas.

For ground water: only one aerobic soil ha lf-life was available and used. Resultant EDWCs could therefore be underestimated because of the use of single aerobic soil halflife.

### 16 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

ATTACHMENT No. 1:

### 17 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

### 18 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

### 19 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

ATTACHMENT No. 2:

Table 1. The physical/chemical and environmental fate/transport properties of rimsulfuron: a detailed summary.

Parameter Value Source
I. Physical/chemical properties Classification Pyrimidinyl Sulfonylurea

Registrant Data and the Web 1 Molecular Formula C 14 H 17 N 5 O 7 S 2 PC Code 129009

Chemical Name (IUPAC) 1-(4,6-dimethoxypyrimidin-2-yl)-3-(3-ethylsulfonyl-2- pyridylsulfonyl)urea

Chemical Name (CAS) N -[[(4,6-dimethoxy-2-pyrimidinyl)amino]carbonyl]-3-(ethylsulfonyl)-2- pyridine sulfonamide CAS Number 122931-48-0

MRIDs: 419316-02 413563-01 Molecular Weight 431.44 pKa 4 H 2 0 Solubility (ppm) 7.3 @ pH 7/25 o C 2 Vapor pressure (25 o C) 1.1x10 -8 torr Equal to 1.447x10 -11 atms. Henry's Law Constant 1.40x10 -12 atms. m 3 . mole -1 (Calculated) Octanol/Water Partition, K ow 1 @ pH7 and 87 @ pH 5 (log K O W 0.034 @ pH7 &1.94 @ pH 5) II. environmental fate/transport properties

Hydrolysis t 1⁄2 = 4.5- 4.7days @ 25 o C, pH 5; 7.1- 7.3days @ 25 o C, pH 7; 4.2- 10.9Hours @ 25 o C, pH 9. MRID: 413563-33

Photolysis in water at pH 7 Half-lives in irradiat ed samples (11.0-12.4 days) were longer than the dark controls (6.4-6 .5 days) indicating th at Direct photolysis is NOT an important degradation pathway

. MRID: 419316-08

Photolysis on soil Half-lives in irradiated /dark control samples w ere in the range of 11- 12 days indicating that photolysis on soil is NOT an important degradation pathway

. MRID: 419316-09

Aerobic soil metabolism t 1⁄2

= 21.3 days for two labels (R 2 = 0.87-0.94) MRID: 413563-34

Anaerobic soil metabolism t 1⁄2

= 17.9-18.1 days for two labels (R 2 = 0.91-0.99) MRID: 413563-35

Aerobic aquatic metabolism t 1⁄2

=0.5-2 Days at 25 o C in the water column; t 1⁄2

= 59-77 Days at 5 o C in the water column. Important Note: Calculated half-lives may NOT represent an aerobic aquatic system because of exposure to light and use of diluted sediment. MRID: 432885-02

Adsorption/Desorption (K d and K oc in L Kg -1 ) K d = 0.23; 1.36; 0.32 and 1.52 corresponding to: K oc = 19; 55; K oc = 55; and 61 MRIDs: 413563-36 413563-37

Terrestrial Field/Lysimeter Dissipation 3 t 1⁄2

(average in the top 0-3” of four soils): 5-18 Days MRIDs: 419316-06 419316-10

1 URL: http://www.scorecard.org/chemical-profiles /text-search.tcl?query_string=Rimsulfuron
2 Solubility was reported to be 10 ppm, elsewhere; URL: http://www.eu-footprint.org/ppdb.html
3 The terrestrial field dissipation study for a soil in Newark, Delaware submitted under MRID 419316-10 was classified as unacceptable study.

### 20 N S O O CH 2 C H 3

S O

O N H 2 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

ATTACHMENT No. 3: Figure 1: Expected degradation scheme for rims ulfuron in the important compartments of the environment

.

N N O

O C H 3

C H 3 N

H N S O O CH 2 C H 3

N

H S O O

O Parent Rimsulfuron

N S O O CH 2 C H 3

N N O

O C H 3

C H 3 N
CO

NH 2 IN-70941

N S O O CH 2 C H 3

N N O

O C H 3

C H 3 NH

IN-70942 N N O

O C H 3

C H 3 NH 2

IN-J290: Pyrimidine Amine IN-E9260: Pyridine Sulfonamide

IN-T5831: Pyrimidinyl Urea N N O

O C H 3

C H 3 NH

CO

NH 2 Sulfonurea-Brigde Cleavage (MINOR

in all s y stems, Exce p t as indicated )

MAJOR in

Aerobic Soil Only Sulfonurea-Brigde Contraction (MAJOR in all systems) Sulfonylurea Bridge

Pyrimidine Ring Pyridine Ring

### 21 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.) ATTACHMENT No. 4: Example Model Runs

A. Surface Water:

**RUN No. 1** FOR rimsulfuron ON fruit tree * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .063( .063) 1 1 19.0 7.3 GROUND( 6.4) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 64.00 0 7.20 .00- .00 .00 7.20

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

-------------------------------------------------------------------- **PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)**
**CONCENTRATION CONCENTRATION**

**-------------------------------------------------------------------- 5.596 .120** 

**--------------------------------------------------------------------**

**RUN No. 2** FOR rimsulfuron ON fruit tree * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPM ) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .031( .054) 2 30 19.0 7.3 GROUND( 6.4) 87.0 .0

FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.-EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 64.00 0 7.20 .00- .00 .00 7.20

UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.0 DEC 12, 2005

-------------------------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC)
CONCENTRATION CONCENTRATION

**-------------------------------------------------------------------- 4.786 .103** 

--------------------------------------------------------------------

### 22 

## Electronic Copy of Previous Drinki ng Waters Analysis (2/6/07; cont.)

B. Ground Water:

SCIGROW VERSION 2.3 ENVIRONMENTAL FATE A ND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U.S. ENVIRONMENTAL PROTECTION AGENCY SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE

SciGrow version 2.3 Chemical: Rimsulfuron Time is 1/12/2007 9:20:20

------------------ ------------------ --------------- --------------- --------------- --------------- ------------ Application Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------ ------------------ --------------- --------------- --------------- --------------- ------------ 0.063 1.0 0.063 5.50E+01 21.3

------------------ ------------------ --------------- --------------- --------------- --------------- ------------ Groundwater screening concentration (ppb) = 1.58E-02

------------------ --------------- --------------- --------------- --------------- --------------- ---------------