### UNITED STATES ENVIRONMENTAL PROTECTI ON AGENCY WASHI NGTON, D.C. 20460 OFFICE OF PREVENTION, PESTICIDES, AND TOXIC SUBSTANCES 

### PC Code: 1 18203 DP Barcode: 3 49860 **MEMORANDUM April 15**  **, 200 9**  **SUBJECT:** Tiered Drinking Water Exposure Assessment for Saflufenacil (Section 3 New

Chemical Use s on Agricultural and Non - agricultural Areas) . **TO:** Kathry

n Montague , Product Manager Joanne Miller, Team Leader Herbicide Branch, RM Team 23 Registration Division (RD) (7505P) George F. Kramer, Ph.D., Chemist Risk Assessment Branch I Health Effects Division (7509P) **FROM:** Greg Orrick, Environmental Scientist

Environmental Risk Branch IV Environmental Fate and Effects Division (7507P) **THROUGH:** R. David Jones, Ph.D ., Senior Agronomist

Elizabeth Behl, Branch Chief Environmental Risk Branch IV Environmental Fate and Effects Division (7507P) **1. EXECUTIVE SUMMARY**  This assessment provides estimated drinking water concentrations (EDWC) of saflufenacil [ BAS 800 H ; N ′ - { 2 - chloro - 4 - fluoro - 5 - [1,2,3,6 - tetrahydro - 3 - methyl - 2,6 - dioxo - 4 - (trifluoromethyl )p yrimidin - 1 - yl ]benzoyl} -N - isopropyl -N - methylsulfamide ] in surface water and in ground water in support of human health risk assessment. Screening EDWCs ( **Table 1** ) of saflufenacil were generated with FIRST for surface water and with PRZM GW for ground water. Modeled application rates represent the maximum use pattern s of five proposed end - use labels with selected uses on row crops, orchard trees, vineyards, tree plantations, and non - agricultural areas (EPA Reg. Number s pending). Remaining model input parameters were chosen according

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to current guidance (USEPA , 2002). EDWCs reflect exposure to saflufenacil and all degradates of concern in drinking water (USEPA, 2009 ). If the screening Estimated Drinking Water Concentrations (EDWC) listed in this memo result in dietary risk exceedances, contact Greg Orrick (703 - 305 - 6140) of Environmental Risk Branch IV (7507P) to request a refined drinking water exposure assessment. **Table 1. Tier**  **ed Drinking Water Exposure Estimates for**  **Proposed Saflufenacil Uses .**  **Source (Tier: Model)**  **1 -**  **in -**  **10 -** **year Peak Exposure (μg/L)**  **1 -**  **in -**  **10 -** **year Annual Mean Exposure (μg/L)**  Surface water (Tier I: FIRST) 37. 3 23. 8 Ground water (Tier II: PRZM GW) 180 173 

### Saflufenacil is a new contact and residual herbicide in the uracil class of compounds that is designed for broadleaf weed control . The compound is nonvolatile and is increasingl y soluble in water with increasing pH . Saflufenacil weakly sorbs to soil ( i.e. , is mobile to highl y mobile in soil) and may

readil y move into surface water through runoff and/or present a ground water concern, depending on the permeability of the soil. Lo w application rates may limit the extent to which the compound runs off into surface water or leaches into ground water. Saflufenacil may

be moderatel y persistent in some environment s, such as acidic to neutral ground water, and may readil y degrade in other environments, such as surficial and alkaline water bodies . The compound dissipates in the environment through chemical and microbially- influenced degradation and b y l eaching and is expected to degrade moderatel y in aerobic s oi l (half

- life of 1 - 5 weeks), less quickl y in acidic to neutral water bodies (half - life of 4 - 10 weeks ), and more quickly in alkaline water bodies (half - life of <1 week). Saflufenacil has fourteen major degradates that were isolated in submitted environmental fate studies. Seven of them, M01, M02, M07, M08, M15, M22, and product 8, are included with the parent as residues of concern. Due to the structural similarity of these degradates to the parent and a lack of toxicity data, they

are assumed to have equivalent toxicity to the parent (USEPA, 2009). Exposure estimates in this assessment reflect total residues of concern (TRC). **2. PROBLEM FORMULATION**  This drinking water assessment uses environmental modeling to provide estimates of surface water and ground water concentrations in drinking water source water (pre - treatment) resulting from saflufenacil use on vulnerable sites . Estimate s reflect drinking water exposure to saflufenacil residues of concern in drinking water , which include the parent compound and its degradates M800H01, M800H02, M800H07, M800H08, M800H15, M800H22, and an unidentified “Prod

uct 8” (chemical names and structures in **Table I .1**  **, Appendix**  **I** ), on a per molar basis (USEPA, 2009 ). Primary routes of transport to source water include runoff, erosion, leaching, and spray

drift. Exposure in surface water from the proposed saflufenacil uses due to runoff, erosion, and spray drift was assessed with the Tier I screening model , FIRST . Exposure in ground water due to leaching was ass essed with the screening ground water model s SCI GROW (a Tier I model) and PRZM GW (a Tier II model ).

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**3. ANALYSIS**  **3.1. Use Characterization**  Saflufenacil , also known as BAS 800 H , is a new contact and residual herbicide in the uracil class of compounds that is absorbed b y roots and foliage, according to the proposed end use product label BAS 800 04H FiRoCrop Herbicide . The compound belongs to the mode - ofaction Group 14/Group E, meaning that it inhibits protoporphy rinogen - oxidase (PPO) , resulting in membrane damage under light and, ultimatel y, plant death. Saflufenacil is proposed for use on b roadleaf weeds via pre -plant and pre - emergence applications to cereal small grains, corn, chickpeas, cotton, edible beans, edible peas, lentils, lupine, sorghum, soy beans, and sunflowers ; via post - emergence applications to fruit trees, nut trees, and vineyards; and via applications to fallow croplands and non - agricultural areas, including pine plantations, rights - of - way , bare ground , and Christmas tree plantations . Saflufenacil is also proposed for use as a desiccant and/or defoliant on sunflower. Five end use formulatio ns of saflufenacil are proposed for registration in the United States. Th ese include BAS 800 04H (FiRoCrop; 29.74 % a .i.), an aqueous suspension concentrate (SC ) for agricultural crop and fallow land uses ; BAS 804 00H (LegVeg; 17.80 % a.i.), a water soluble granule (WG) containing 50.20% imazethapy r and for agricultural uses ; BAS 781 02H (6.24% a.i.), an emulsifiable concentrate (EC) containing 55.04% dimethenamid - P and for agricultural uses; BAS 800 01H (TNV; 70.0% a.i.), a water soluble granule (WG) for orchard and vineyard uses; and BAS 800 02H (SharpenTM; 12.27% a.i.) , an emulsifiable concentrate (EC) for non - agricultural uses . **Table 2**  lists the proposed use patterns and maximum application rates on the proposed labels for these five end use formulations . The proposed maximum single and annual application rate for saflufenacil is the same, at 0.356 lbs a.i./A on non - agricultural are a s (BAS 800 02H ; SharpenTM ) , which characterizes the maximum use pattern of saflufenacil for this national - level, screening drinking water exposure assessment . BAS 800 04H ( FiRoCrop) and BAS 800 01H (TNV) have a proposed maximum annual application rate of 0.13 lbs a.i./A for selected agricultural crop, orchard, and fallow land uses. The multi - active ingredient products, BAS 804 00H (LegVeg) and BAS 781 02H , have lower proposed maximum annual application rates for labeled uses, but include directions not to exceed an annual rate of 0.134 lbs saflufenacil per acre from all sources of the chemical.

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**Table 2. Proposed use patterns for saflufenacil end use**  **products. Product**  **L abel**  **Active**

**Ingredient (%) Use**  **Maximum Single Application R**  **ate (lbs**  **saflufenacil /A)**  **Maximum Annual** 

**Application Rate (lbs**  **saflufenacil /A)**  **Additional Application Directions**

BAS 800 04H (FiRoCrop) Saflufenacil

(29.74%) Fallow , post - harvest 0.13 0.13 Equipment: ground or aerial.

Field corna , sweet corn b , and popcorn 0.13 0.13 Application timing: 14 - 30 days prior to planting (incorporated or surface) or pre - emergence. Application rates 15 - 30 days prior to planting vary by soil texture and organic matter (higher rates on finer soils and soils with higher organic matter); not so 14 days prior to planting. Equipment: ground or aerial. Sorghum Cotton 0.045 0.045 Application timing: prior to accumulation of 1 - inch of rainfall or irrigation to occur 21 days prior to planting. Equipment: ground or aerial. Legume vegetables c 0.089 0.089 Application timing: pre -plant or pre - emergence (pre -plant only for lentils). Equipment: ground or aerial. Soy beans (tolerant) Small grains d 0.13 0.13 Application timing: pre -plant or pre - emergence (dormant or during and/or after spring green up for winter wheat at 0.045 lbs a.i./A). Equipment: ground or aerial. Sunflower 0.045 0.089 Maximum number of applications per year: 2 (interval not stated). Application timing: at least 7 days prior to harvest (for desiccation). Equipment: ground or aerial. BAS 804 00H (LegVeg) Saflufenacil

(17.80%) and Imazethapyr (50.20%) Clearfield® corn 0.023 0.02 3 Maximum annual app. rate from all sources: 0.134 lbs saflufenacil/A for Clearfield® corn; 0.089 lbs saflufenacil/A for legume vegetables and soybeans. Application timing: pre -plant or pre - emergence (pre - emergence only for Clearfield® corn). Equipment: ground or aerial. Legume vegetables (per region) e 0.017 (Southern peas only: 0.023) 0.017

(Southern peas only: 0.023) Soy beans 0.023 0.023 BAS 781 02H Saflufenacil

(6.24%) and Dimethenamid - P (55.04%) Field corna , sweet

corn b , and popcorn 0.11 0.11 Maximum annual app. rate from all sources: 0.134 lbs saflufenacil/A. Application timing: 14 - 30 days prior to planting (incorporated or surface) or pre - emergence. Application rates 15 - 30 days prior to planting vary by soil texture and organic matter (higher rates on finer soils and soils wi th higher organic matter); not so 14 days prior to planting. Equipment: ground, aerial, or chemigation. Grain sorghum

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**Table 2. Proposed use patterns for saflufenacil end use**  **products. Product**  **L abel**  **Active**

**Ingredient (%) Use**  **Maximum Single Application R**  **ate (lbs**  **saflufenacil /A)**  **Maximum Annual** 

**Application Rate (lbs**  **saflufenacil /A)**  **Additional Application Directions** BAS 800 01H (TNV) Saflufenacil

(70%) Citrus fruit, pome fruit,

stone fruit, tree nuts 0.045 0.13 Maximum number of applications per year: 3 (at least 21 days apart). Application timing: post - emergence. Equipment: ground. Grape vines 0.022 0.066 BAS 800 02H (SharpenTM) Saflufenacil

(12.27%) Christmas tree

plantations 0.356 0.356 Application timing: post - emergence for Christmas tree plantations; pre -plant for conifer and hardwood plantations; no directions for non - agricultural areas. Equipment: ground or aerial. Conifer and hardwood plantations Non - agricultural areas a Field corn includes conventional or herbicide - tolerant field corn grow n for grain, seed, or silage . b Sweet corn does not include sweet corn grown for seed. c Legume vegetables include chickpeas, selected edible beans, selected edible peas, and lentils. d Small grains include wheat, barle y, canaryseed, oats, millet, rye, and triticale. e Legume vegetables (per region) includes lentils, white lupins, chickpeas, dry edible peas, English peas, and Southern peas in the states east of and including North Dakota, South Dakota, Wyoming, Colorado , and New Mexico, except the states east of and including Vermont, Massachusetts, and Connecticut; succulent peas, dry edible peas, lentils, and chickpeas in Idaho, Montana, Nevada, Oregon, Utah, and Washington; and chickpeas in Arizo na and California.

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**3.2. Fate and Transport Characterization**  Saflufenacil [N’ - [2 - chloro - 4 - fluoro - 5 - (3 - methyl - 2,6 - dioxo - 4 - (trifluoromethyl) - 3,6 - dihydro - 1(2H) -py

rimidinyl)benzoyl] -N - isopropyl -N - methylsulfamide ] is nonvolatile, hydrophilic, and mobile to highl y mobile in soil , as dissolved in surface wat er runoff and/or ground water . The compound dissipates in the environment through chemical and microbiall yinfluenced degradation and by leaching and is expected to degrade moderately in aerobic s oil (h alf - life of 1 - 5 weeks), less quickly in acidic to neutral water bodies (half - life of 4 - 10 weeks), and more quickl y in alkaline water bodies (half - life of <1 week). While s aflufenacil may readil y degrade in surficial and alkaline water bodies, the compound may be moderately

persistent in acidic to neutral ground water . **Table 3** summarizes the submitted environmental fate data for saflufenacil. **Table 3 . General chemical properties and environmental fa** **te parameters of saf**  **lufenacil .**  **Parameter Value**  **Source Selected Physical/Chemical Parameters**  Molecular mass 500.86 MRID 4 7127817 Vapor pressure (extrapolated) 20°C: 3.4 x 10 - 17 torr 25°C: 1.5 x 1 0 - 1 6 torr MRID 4 7127821 Water solubility (20  C) pH 4: 1 4 mg/L pH 5: 25 mg/L pH 7: 2,100 mg/L pH 9: ndA MRID 47127819 Henry’s Law Constant (25° C) 4.0 1 x10 - 20 atm - m3 /mol MRID 47127822 pKa 4.41 MRID 47127817 Log octanol -to -water partition coefficient ( log KOW at pH <4.41 ) 2.56 MRID 47127818 **Persistence** Hydrolysis half

- life ( 25  C) pH 5: Stable pH 7: 248 d pH 9: 4.93 d MRID 47127823 Aqueous photolysis half

- life (22  C) 56 d (buffer; pH 5)

22 d (pond water; pH 7.1) MRID 47699901 Soil photolysis half

- life (22  C) 66 d (12 -hr light/day) 84 d (continuous irradiation) MRID 47127825 Aerobic soil metabolism half - life (25  C) 9.3 d (silt loam ; pH 6.1 )

23.3 d (loamy sand ; pH 5.9 ) 26.2 d (silty clay loam ; pH 5.5 ) 32.1 d (sandy loam ; pH 6.8 ) MRID 47445901

Anaerobic soil metabolism half - life (25  C) [ 217 d] B (loamy sand ; pH 5.0 - 6.0 ) MRID 47611201 Anaerobic aquatic metabolism half - life (25  C) [ 29.4 d] B (pH 5.5 - 8.5) MRID 47127828 Aerobic aquatic metabolism half - life (25  C) 70.7 d (dark ; pH 5.8 - 6.7 )

3.6 d (12 -hr light/ day ; pH 6.1 - 8.0 ) MRID 47127827

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**Table 3 . General chemical properties and environmental fa** **te parameters of saf**  **lufenacil .**  **Parameter Value**  **Source Mobility**  Range of Freundlich organic carbon normalized partition coefficients (KFOC ) 9.3

– 55 L/kg OC (n=6) MRID 47127829 **Field Dissipation** Terrestrial field dissipation half

- life ( Soil series ; texture) Georgia: 10 .7 d ( Fuquay ; sandy loam) MRID 47127834 Arkansas: I llinois: Manitoba : 6.25 d ( Commerce ; silt loam)

11.1 d ( Cisne - Huey Complex ; silt loam) 35.5 d (Neuhorst ; loam) MRID 47127835 Washington: Ontario : C alifornia: 1.4

–4.6 d ( Quincy ; loamy sand)

7.3

–23.6 d ( Brant ; loam) 13.0

–32.2 d ( San Joaquin ; clay loam) MRID 47127836 A “nd” means not determined due to degradation. B Half - lives are highly uncertain. 

### 3.2.1. **Transport and Mobility** Saflufenacil will not significantly volatilize due to a low vapor pressure ( 1.5 x 10 - 16 

### torr at 25 °C ; MRID 47127821 ) and a solubility in water that increases with increasing pH ( 1 4 mg/L (pH 4) to 2.1 x 10 3 

### mg/L (pH 7 ) at 20°C ; MRID 47127819 ). Saflufenacil’s solubility in water could not be determined at pH 9 due to hydrol ys is. The range of solubility in water across pH values indicate s that the compound exhibits acid/ base behavior . Saflufenacil is expected to be ionic at pH values above its pKa of 4.41 (MRID 47127817) . Dissociation was not determined above pH 5.28. Given the similarity in water solubility at pH 4 ( 14 mg/L) and pH 5 (25 mg/L) and the substantially higher water solubility

at pH 7 ( 2.1 x 10 3 

### mg/L), it is uncertain whether saflufenacil has an additional dissociation constant above pH 5 and whether the water solubility value at pH 5 is accurate. Acid/base behavior with respect to octanol - to - water partitioning was not studied, as the log KOW 

### (2.56) was onl y determined for the neutral species at an unreported pH value less than the compound’s pKa of 4.41 (MRID 47127818). At environment al pH values (initial soil pH values of 5.5 - 8.0) , s aflufenacil weakl y sorbs to soil (MRID 47127829). H owever, the compound display s affinity to organic matter ( e.g. , the coefficient of variation (CV) across six soils for KFOC 

### ( 60 %) is less than that for KF 

### ( 97 %) ) . A ccording to the FAO soil mobility classification scheme , s aflufenacil is mobile to highly mobile in soil (KFOC 

### of 9.3 to 55 L/kg OC 

### ) and may readil y move into surface water through runoff and/or to ground water , depending on the permeability of the soil (USEPA , 2006) . **3.2.2. Degradation**  Saflufenacil degrades in the environment through chemical and microbially - influenced processes, some of which are not well understood. Hydrolysis of saflufenac il is pH - dependent, as the compound degrades readil y in alkaline environments (half - life of 5 days at pH 9) and

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persists in acidic to neutral conditions (stable at pH 5; half - life of 248 day s at pH 7; MRID 47127823). Major hydrolysis degradates include M04, M07, M 15, and M33 (chemical names structures , and maximum formed amounts of all degradates are listed in **Table I .1, Appendix I**  ). The compound is moderately photol yz ed in clear, near- surface water (half - liv e s of 56 days in a sterile pH 5 buffer and 22 day s in unsterile pH 7.1 pond water ; MRID 47699901 ) and on so il (half

- liv e s of 66 day s under 12 hours of irradiation per day and 84 day s under continuous irradiation followed b y conv ersion to a value reflecting 12 hours of irradiation per day ; MRID 47127825 ). No major degradates were formed in the sterile pH 5 buff er. M29, M33, and an unidentified compound were major degradates in the pond water. Major photolysis degradates on soil included M15 under 12 hours of light per day and Product 8 under continuous irradiation, an unidentified compound that degraded to M01 during handling and anal ysis. These degradates were not formed in major amounts in the dark , where M07 and M08 were. In aerobic soil, saflufenacil degraded with a half - life ranging from 9.3 to 32 days in four soils (pH 5.5 to 6 .8 ; MRID 47445901 ). The major degradates were M01, M02, M07, M08, M 22 , M26, and M31 , which were up to 10%, 31%, 52%, 66%, 16%, 18%, and 18% of the applied, respectivel y . M02, M08, and M22 were major degradates in all four soils. M26 was a major degradate in only

the silt loam soil , in which saflufenacil degraded the quickest. A mixture of volatile compounds (M26, M29, and carbon dioxide) also accounted for up to 16.5% of the applied radioactivity in the silt loam test system ; however , their individual proportions were not determined. It is unusual that the most prominent degradate (M08) in this aerobic study wa s a reduction product . Its presence is likel y the result of enzymatic ( i.e. , uracil hydrogenase) activity . In anaerobic soil, saflufenacil degraded with a half - life o f 217 days in one soil (pH 5.0 - 6.0 ; MRID 4 7611201 ). Major degradates included M01, M02, and M08 , which were a maximum of 14%, 24%, and 25% of the applied, respectivel y . Results of the study are highl y uncertain because anaerobic conditions were marginal; the mean redox potential in the post - f lood water was - 34  88 mV (n=28). In anaerobic aquatic s ys tems, saflufenacil degraded with a half - life of 29.4 days in one sy stem (pH 5.5 - 8.5). Major degradates included M07, M15, M29, M33, and 1,1,1 - trifluoro - 2 - propanol , which were a maximum of 71%, 16%, 11%, 16%, and 19% of the applied, respectivel y, in the total sy stem . Results of the study are highl y uncertain because anaerobic conditions in the water layer, where the majority of the applied partitioned, were marginal; redox potential was not measured in the water layer ( it was reducing to strongl y reducing in the sediment layer) and dissolved oxygen in the water layer was up to 1.7 mg/L. Additional uncertainty was due to a declining material balance for the uracil - labeled s ystem and s ignificant dissipation (35 - 50% of the applied) of saflufenacil in both systems between the 30 and 62 day sampling intervals, when dissolved oxygen appeared to be most elevated. Due to the detection of major and minor degradation products in this study that were not detected in the aerobic aquatic metabolism or hydrolysis studies, it appears that conditions were partially anaerobic. In aerobic aquatic s ys tems, saflufenacil degraded with a half - life of 70.7 days at pH 5.8 - 6.7 (MRID 4 7127827 ). The major transformation products were M07, M29, M33, and carbon

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dioxide, which were a maximum of 23%, 8.8%, 23%, and 11% of the applied, respectivel y, in the total system. Results of the study are uncertain because dissolved ox yge n con centrations ( 2.7 - 5.5 mg/L, corresponding to ~33 - 65% saturation at 25°C ) were less than the ty pical range ( 7 - 10 mg/L) and recoveries of the uracil - labeled s ys tems were highl y variable (76% to 114%). Regardless, redox potentials in the water layer (ranging +150 to +410 mV ) indicate that the test sy stem was aerobic. It is not understood why saflufenacil appears to degrade with shorter halflives in aerobic terres trial and anaerobic aquatic s ystems (9.3 to 32 days) than in anaerobic terrestrial and aerobic aquatic systems (half - lives of 71 to 217 days). **3.2.3. Field Studies**  Three terrestrial field dissipation studies were conducted for saflufenacil using five sites in the United States and two sites in Canada, each with three bare ground plot s that had <1% slope and no runoff collection equipment . One study was conducted on a sandy loam soil (Fuquay soil series) in Georgia ( MRID 47128234) . Saflufenacil was broadcast once at a target application rate of 0.40 kg a.i./ha (0.357 lb a.i./A), which is the proposed maximum application rate ( for use on tree plantations an d non - agricultural areas ) . Total water input was 122% of the historical average. Soil samples (0 - 12 0 cm depth) were collected through 451 days after treatment. The mean zero - time concentration of s aflufenacil in the 0 - 7.5 cm soil depth was 0.19 ppm, which was 57 % of the theoretical. Saflufenacil dissipated in the whole soil profile with a half - life of 11 days . The compound was detected above the limit of quantitation (LOQ = 0.01 ppm or 3 % of the theoretical zero - time concentration) at a maximum depth of 45 - 60 cm , 32 day s after treatment. For each study, t est sites were anal yz ed for M01, M02, M07, M08, M15, and M22. In the Georgia sandy l oam, M08, M01, and M02 were detected above the LOQ (detections between the L OD and LOQ were not reported). M08 was detected in the 0 - 7.5 cm and 7.5 - 15 cm soil depth s at maximum co ncentration s of 0.04 ppm on the day of treatment ( 21% of the initial soil concentration of saflufenacil) and 0.05 ppm at 6 day s after treatment (26% of the initial soil concentration of saflufenacil), respectivel y, and was detected above the LOQ at a maximum depth of 90 - 105 cm at 46 and 75 days after treatment . M01 was detected in the 0 - 7.5 cm soil depth at a maximum concentration of 0. 02 ppm (10.8% of the initial soil concentration of saflufenacil) from 0 - 8 days after treatment and was not detected above the LOQ below the 7.5 - 15 cm depth. M02 was detected in the 0 - 7.5 cm soil depth at a maximum concentration of 0.01 ppm ( 5.4% of the initial soil concentration of saflufenacil) at 0, 1, 2, and 6 days after treatment and was not detected above the LOQ in soil below the 0 - 7.5 cm depth. A second study was conducted on silt loam soils in Arkansas (Commerce soil series) and Illinois (Cisne - Huey

Complex soil series) and on a loam soil (Neuhorst soil series) in Manitoba (MRID 47128235) . Saflufenacil was broadcast once at a target application rate of 0.15 kg a.i./ha (0.134 lb a.i./A), which is the proposed maximum application rate f or u se on corn, sorghum, small grain crops, and fallow l and . Total water input at these sites was 9 7% to 108 % of the historical average. Soil samples (0 - 12 0 cm depth) were collected through 360 days after treatment. The mean zero - time concentration s of saflufenacil in the 0 - 7.5 cm soil depth of each site were 0.16 ppm, 0.14 ppm, and 0.09 ppm, which were 101 % , 107%, and 48 % of the theoretical , respectivel y . Saflufenacil dissipated in the whole soil profile of each site with

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respective half

- lives of 6.25, 11.1, and 35.5 days. The compound was detected above the limit of quantitation (L OQ = 0.01 ppm or 5.3 % to 7.6% of the theoretical zero - time concentration) at a maximum depth of 7.5 - 15 cm in the Arkansas silt loam soil (2 and 6 - 8 days after treatment) , a m aximum depth of 0 - 7.5 cm in the Illinois silt loam soil (0 - 45 day s after treatment) , and a maximum depth of 15 - 30 cm in the Manitoba loam soil (6 days after treatment) . In the Arkansas silt l oam, M08 was the only degradate detected above the LOQ. In the 0 - 7.5 cm soil depth , M08 was detected at a maximum co ncentration of 0.03 ppm ( 19 % of the initial soil concentration of saflufenacil) at 75 to 90 days after treatment and was not detected above the LOQ below this depth . In the Illinois silt loam, M08 was the onl y degradate detected above the LOQ. In the 0 - 7.5 cm soil depth , M08 was detected at a maximum co ncentration of 0.03 ppm (21 % of the initial soil concentration of saflufenacil) at 3 0 to 45 days after treatment and was not detected above the LOQ below the 7.5 - 15 cm depth . In the Manitoba loam, M07 and M08 were detected above the LOQ. In the 0 - 7.5 cm soil depth , M08 was detected at a maximum co ncentration of 0.03 ppm ( 33 % of the initial soil concentration of saflufenacil) at 6 days after treatment and was not detected above the LOQ below this depth. M07 w as detected in the 0 - 7.5 cm soil depth at a concentration of 0.01 ppm (15% of the initial soil concentration of saflufenacil) at 45 day s after treatment and was not detected above the LOQ below this depth. The third study

was conducted on a loamy sand soil ( Quincy soil series) in Washington, a loam soil (Brant soil series) in Ontario, and a clay loam soil (San Joaquin soil series) in California (MRID 47128236) . Saflufenacil was broadcast three times (21 - to 23 - day interval) at each site at a target application rate of 0.05 kg a.i./ha/application (0.045 lb a.i./A/application), which is the proposed m aximum application pattern for use on orchard tree s . Total water input at these s ites was 131% to 846% of the historical average. Soil samples (0 - 12 0 cm depth) were collected from each site through 2 0 days after the first treatment , 20 day s after the second treatment, and 360 days after the third . Following the first application, the mean zero - time concentration s of saflufenacil in the 0 - 2 .5 cm soil depth of each site were 0.09 ppm , 0.10 ppm , and 0.08 ppm, which were 64 % , 76 %, and 50 % of the theoretical, respectively . Saflufenacil dissipated in the whole soil profile , following the first and third applications, with respective half - lives of 4.6 and 1.4 days in the Washington loamy sand, 7.3 and 23.6 day s in the Ontario loam, and 13.0 and 32.3 days in the California clay loam . The compound was detected above the limit of quantitation (LOQ = 0. 01 ppm or 6 .3% to 7.6% of the theoretical zero - time concentration) at a maximum depth of 5 - 15 cm in all three soils ( 2 - 10 days after the first treatment and up to 76 day s after the third treatment). However, samples were not analyzed to a sufficient depth to define leaching at the Ontario site. At 2, 5, and 9 day s following the first application , samples were not anal yz ed below 15 cm despite th e detection of saflufenacil in the 5 - 15 cm depth at these sampling interval s. Samples were anal yz ed to a depth of 30 - 45 cm at all other sampling intervals, with no detection of saflufenacil above the LOQ at that depth on any sampling interval. In the Washington loamy sand , M08 was the onl y degradate detected above the L OQ. In the 0 - 2 .5 cm soi l depth , M08 was detected at a maximum co ncentration of 0.02 ppm following the all three applications and was not detected above the LOQ b elow the 2.5 - 5 cm depth . In the Ontario loam, M08 and M01 were detected above the LOQ. In the 0 - 2 .5 cm soil depth , M 08 was detected at a maximum co ncentration of 0.0 5 ppm at 1 day after the third application and was not

### 11

detected above the LOQ below the 5 - 15 cm depth . Inthe 0 - 2 .5 cm soil depth , M01 was detected at a maximum co ncentration of 0.02 ppm at 1 0 days after the third application and was not detected above the LOQ below this depth . Inthe California clay loam, M01, M07 , and M08 were detected above the LOQ. In the 0 - 2 .5 cm soil depth , M01 was detected at a maximum co ncentration of 0.02 ppm at 20 days af ter the third treatment , and M07 and M08 were detected at maximum concentrations of 0.02 ppm and 0.01 ppm, respectivel y, at 20 and 45 days after the third treatment. M01, M07, and M08 were not detected above the LOQ below this depth . **3.2.4. Environmental Degrad**  **ates** Major identified environmental degradates of saflufenacil are M01, M02, M04, M07, M08, M15, M22, M26, M29, M31, M33, TFP, ‘product 8’, and ‘ unknown 3/2/2’, an unidentified photodegradate with a liquid chromatography retention time of 3.9 minutes . Available IUPAC names and chemical structures are listed in **Table I.1 of Appendix I**  as well as maximum and final amounts formed in the submitted studies . **Table I.2 of Appendix I** lists the e leven m inor degradates of saflufenacil that were identified as well . Degradates M01, M02, M08, and product 8 have an intact uracil ring and are most similar to the parent compound. M01 and M02 were major demethyl ation products in the aerobic and anaerobic soil metabolism studies . Product 8 was a major photodegradate o n soil that degraded to M01 but was increasing in concentration at the end of the study . Reduction/saturation of the uracil ring of saflufenacil produced M08, which was a major degradate in the aerobic soil metaboli sm and soil photoly sis studies. Degradates M04, M07, M15, and M22 have a cleaved uracil ring, but remain structurall y similar to the parent compound. M04 w as a major hydrol ytic product at pH 9 but was not detected 18 days after its peak concentration. M 07 was a major degradate in every submitted environmental fate laboratory study with the exception of the anaerobic soil metabolism study . M15 was a major hydrolytic degradate at pH 9 and a major degradate in the anaerobic aquatic metabolism study . M22 was a major degradate in the aerob ic soil metabolism study . Degradates M26, M29, M31, M33, and TFP are trifluorinated cleavage products of the uracil ring that were identified in submi tted studies. M29 is trifluoroacetic acid ( CASRN: 76 - 05 - 1 ) , a degradation product shared b y pesticide s , hydrochlorofluorocarbons, (HCFC), and hydrofluorocarbons (HFC). According to the Hazardous Substances Data Bank, with a vapor pressure of 110 torr at 25°C, trifluoroacetic acid will volatilize if released to the air or dry soil (USNIH, 2009) . It ’s half - life in air is estimated at 31 days due to reaction with hydrox yl radicals. However, if released to water bodies or wet soil , trifluoroacetic acid will form a persistent anion (pKa of 0.52) that will not degrade by abiotic or microbial means . The compound has been detected in surface water, seawater, and precipitation (USNIH, 2009) . F luoroform (trifluoromethane ; CASRN: 75 - 46 - 7) is a possible terminal product of the trifluorinated degradates of saflufenacil. According to the Hazardous Substanc es Data Bank, f luoroform will volatilize from water and soil based on a Henry's Law constant of 0.095 atm m 3 

### /mol and a vapour pressure of 3.5 x 10 4 

### torr at 25° C (USNIH, 2009). However, the compound has been detected in surface water and ground water. It will persist in air with a half - life of 180

### 12

ye ars and graduall y diffuse into the stratosphere with a half - life of 20 ye ars (USNIH, 2009) . As an HFC , fluoroform is included with the greenhouse gas es subject to the Kyoto Protocol (United Nations, 1998) . **3.2.5. Residues of Concern**  The Residues of Concern Knowledgebase Subc ommittee (ROCKS) of the Health Effects Division included as residues of concern in drinking water, saflufenacil parent, M01, M02, M07, M08, M15, M22, and product 8. Due to the structural similarity of these degradates to the parent and a lack of toxicity

data, they

are assumed to have equivalent toxicity to the parent (USEP A, 2009 ). Because product 8 degrades to M01 during handling and/or anal ys is, identification of the compound and its inclusion as an anal yt e in environmental chemistry methods are not requested . Drinking water exposure to the residues of concern is estimated using available chemical properties and environmental fate data. A total residues of concern (TRC ) approach wa s used because degradation studies were not performed on the degradates of concern and their patterns o f formation and decline were not always well defined in studies on the parent compound . **Table 4** lists the environmental fate parameters for the saflufenacil TRC that were relevant for exposure modeling . These parameters reflect regression of the total residues at each interval of the biodegradation studies. Batch equilibrium data were available for the individual degradates of concern (MRID 47127830). Chemical properties of the parent compound were used to represent those of the residues of concern due to the lack of data on the degradates of concern. TRC metabolism half

- lives were based on the phenyl - labeled s ys tems only in order to include M07, which doesn’t retain the radiolabel on the uracil ring. **Table 4 .**  **Selected e nvironmental fate parameters of**  **the total residues of concern .**  **Parameter Value**  **Source Persistence**  Hydrolysis half

- life (25  C) Stable (pH 5, 7 ) MRID 47127823 Aqueous photolysis half

- life (22  C) 9 0.9 d (pH 5) MRID 47699901 Aerobic soil metabolism half - life (25  C) 9 61 3 d (silt loam ; pH 6.1 )

1822 d (loamy sand ; pH 5.9 ) 1433 d (silty clay loam ; pH 5.5 ) 987 d (sandy loam ; pH 6.8 ) MRID 47445901 Aerobic aquatic metabolism half - life (25  C) 416 d (pH 5.8 - 6.7) MRID 47127827

**Mobility** Range of Freundlich organic carbon normalized partition coefficients (KFOC ) (n=6) M01: 4.8

–27 L/kg OC M02: NC A

–41 L/kg OC M07: 3.3

– 111 L/kg OC M08: 4.8

–20 L/kg OC M15: 9.6

– 57 L/kg OC M22: NC A

–25 L/kg OC MRID 471278 30

A “NC” means not calculated due to no absorption.

### 13

**3.3. Drinking Water Exposure Modeling**  **3.3.1. Models**  The FQPA Index Reservoir Screening Tool (FIRST v1.1.1, Mar. 25, 2008; USEPA, 2008 ) is a Tier I screening model that simulates the upper- end exposure of the standard water body , the Index Reservoir, to pesticide residues in runoff and spray drift from an application within the standard watershed. Peak and annual mean EDWCs are generated to estimate acute and chronic exp osure. The Index Reservoir covers 5.2 hectares (ha) with an average depth of 2.74 meters (m) in a standard watershed of 172.8 ha. A more detailed description of the index reservoir watershed can be found in Jones et al ., 1998. The FIRST model and user’s manual are available from the EPA Water Models web -page (USEPA, 2009 ). Screening Concentration in Ground Water (SCI - GROW v2.3, Jul. 29, 2003 ; USEPA, 2002a) is a regression model used as a screening tool to estimate pesticide concentrations found in ground water used as drinking water. SCI - GROW was developed by fitting a linear model to ground water concentrations with the Relative Index of L eaching Potential (RILP) as the independent variable. Ground water concentrations were taken from 90 - day average high concentrations from Prospective Ground Water studies. The RILP is a function of aerobic soil metabolism and the soil - water partition coefficient. The output of SCI - GROW represents the concentrations of pesticide residue that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination and likely

to serve as a drinking water source. The SCI - GROW model and user’s manual is also available from the EPA Water Mo dels web -page (USEPA, 2009 ). Both FIRST and SCI - GROW were used to estimate screening - level exposure of drinking water sources to total residues of concern of saflufenacil . PRZM GW is a graphical user interface that automates the Pesticide Root Zone Mode l (PRZM v3.12.2; May

12, 2005; Suarez, 2006 ) under a NAFTA - harmonized conceptual model for ground water modeling that was subject to peer review b y the FIFRA SAP (USEPA, 2005; 2005a) . The conceptual model ( **Figure 1** ) rep resents vulnerable private drinking water wells in the vicinity

of agricultural environments. In this conceptualization, the pesticide is applied to the soil surface (or plant canopy) and precipitation or irrigation drive s the pesticide into the soil. Meteorological, crop, biological, chemical, and management processes affect the transport of the pesticide as it moves through the soil and into a saturated zone. Horizontal movement of pesticide ( advection via runoff or erosion) and subsequent removal is neglected for this model.

### 14

**Figure 1 . Depiction of the general ground water scenario concept for estimating pesticide**  **concentrations in drinking water with PRZM GW.** The saturated zone of the conceptual model is a shallow surficial aquifer with a water table nine meters below the surface. Concentrations are based on a vertical spatial average starting at the top of the water table down to a depth of 1 meter below the water table. This is meant to approximate the vertical depth from which a well screen may sample and supply

as drinking water. The location of the well screen was chosen to sample the higher concentrations expected nearer to the water table . The conceptual model includes meteorological events with daily resolution that can significantl y affect pesticide transport including precipitation, evaporation, snow, temperature, and wind. Crop descriptions are needed onl y in regard to how they impact hydrology or pesticide interception. Management practices such as irrigation and setback distances are included in the conceptual model. The default environmental fate scheme uses the aerobic soil degradation rate in the top 10 cm and a linearly declining rate with depth to 1 meter, below which only hydrolysis is assumed to occur. **3.3.2. Input Parameters**  Input parameters for FIRST follow in **Table 5**  . The modeled use pattern represents the maximum proposed use pattern ( one aerial application per year at 0.356 lbs a.i./A). This is proposed for use on Christmas tree, conifer, and hardwood plantations and non - agricultural areas ( SharpenTM formulation) . Water T able

**Lateral Groundwater Movement**  100 cm Set back distance

Biodegradation Zone 100 cm

Abiotic Degradation Pesticide Application Area Potable Well

Depth to Water Table Water T able

**Lateral Groundwater Movement**  100 cm Set back distance

Biodegradation Zone 100 cm

Abiotic Degradation Pesticide Application Area Potable Well

Depth to Water Table

### 15

**Table 5 . FIRST input parameters for**  **total residues of saflufenacil**  **following use on**  **tree plantations and**  **non -**  **agricultural areas. S**  **ource data are in Tables 2 -**  **4 .**  **Input Parameter Value**  **Comments Source**  Application rate (lbs a.i./A) 0.356 Maximum proposed single application rate. Proposed label . Number of applications per year 1 Maximum proposed number of applications per year at the maximum proposed single application rate. Proposed label . Percent cropped area 100% Default for non - agricultural uses. Effland et al. , 1999 Organic Carbon Partition Coefficient (KOC ) (L/kg OC ) 5.9 Represents the mean of the lowest KOC values for the residues of concern in non - sand soil s (n=7) . MRID 47127829 MRID 471278 30 Aerobic soil metabolism half - life (days) 6833 Represents the upper 90% confidence bound on the mean of four half - lives for the residues of concern . MRID 47445901 Wetted in? No Not required. Proposed label. Method of application Aerial Proposed application method of highest potential spray drift. Proposed label. Solubility in water (ppm) 2100 Solubility in pH 7 water. MRID 47127819 Aerobic aquatic metabolism half - life (days) 1247 Represents 3x the single available half - life for the residues of concern. MRID 47127827 Aqueous photolysis half

- life (days) 90.9 Represents the maximum environmental phototransformation half - life for the residues of concern. MRID 47699901 

### Chemical property input values were chosen in accordance with current input parameter guidance (USEPA, 2002). Based on anal ys is of total residues of concern, the 90% confidence bound on the mean aerobic soil metabolism half - life (6833 d) , three times the single available aerobic aquatic metabolism half - life (1247 d), and the maximum environmental phototransformation value (90.9 d) were selected . The KOC 

### input represents the mean of seven values that represent the lowest non - sand KOC 

### for each of the identi fied residues of concern ( i.e. , saflufenacil, M01, M02, M07, M08, M15, and M22). S tandard percent cropped area s (PCA) are used as conservative default estimate s of the extent of watershed on which agricultural crops of unknown specific PCA are grown (Efflan d et al. , 1999). Because PCA values were not available for non - agricultural uses, they were not used for exposure estimates for these uses . Input parameters for the SCI - GROW model appear in **Table 6**  . The mean of the lowest reported organic carbon partition coefficient s (KOC 

### = 5.9 L/kg OC 

### ) for the residues of concern was selected. The median total residue half - life (1627 d) from four aerobic soils was selected to approximate the biodegradation kinetics of the residues of concern in aerobic soil environments.

### 16

**Table 6 . SCI**  **- GROW input parameters for**  **total residues of saflufenacil**  **. Source data are in**  **Tables 2 -**  **4 .**  **Input Parameter Value**  **Comments Source**  Application Rate (lbs a.i./A) 0.356 Maximum proposed single application rate. Proposed label . Applications per Year 1 Maximum proposed number of applications per year at the maximum proposed single application rate. Proposed label . Organic Carbon Partition Coefficient (KOC ) (L/kg OC ) 5.9 Represents the mean of the lowest reported KOC values. MRID 47127829 MRID 47127830 Aerobic Soil Metabolism Half - life (days) 1 627 Represents the median total residue halflife in four soils. MRID 47445901 

### Exposure estimates from the Tier I model SCI - GROW were expected to result in chronic dietary risk exceedances, considering food plus drinking water (personal communication with George Kramer, HED; Apr. 6, 2009). Therefore, the Tier II screening model PRZM GW was used to refine exposure estimates in ground water for drinking water exposure assessment. Input parameters for PRZM GW appear in **Table s**  **7 and 8**  . The mean of the lowest reported organic carbon partition coefficient s (KOC 

### = 5.87 L/kg OC 

### ) for the res idues of concern was selected. The median total residue half

- life (1627 d) from four aerobic soils was selected to approximate the biodegradation kinetics of the residues of concern in aerobic soil environments. The modeled scenario represents an acidic soil where saflufenacil will not hydrolyze; therefore, an arbitrarily high hydrol ys is half

- life (10,000 days) was selected to approximate stability to hydrol ys is. **Table 7. PRZM GW**  **input parameters for total residue**  **degradation rate s**  **and the proposed use**  **pattern .**  **Source data are in Tables 2 -**  **4 .**  **Input Parameter Value**  **Comments Source**  Application Rate (kg a.i./ha) 0. 4 Maximum proposed single application rate. Proposed label . Applications per Year 1 Maximum proposed number of applications per year at the maximum proposed single application rate. Proposed label . Application Date July 1 st Arbitrarily selected date for a non agricultural application. (none) Chemical Application Method 2 Represents foliar application. (none) Hydrolysis Half

- life (days) 10,000 Represents stability to hydrolysis. MRID 47127823 Aerobic Soil Metabolism Half - life (days) 1 627 Represents the median total residue halflife in four soils. MRID 47445901 Organic Carbon Partition Coefficient (KOC ) (L/kg OC ) 5.87 Represents the mean of the lowest reported KOC values. MRID 47127829 MRID 47127830 

### A previously

developed scenario for corn grown in the Delmarva Peninsula was modifie d for this assessment of non - agricultural areas on the same vulnerable soil , resulting in a provisional “Delmarva non - ag” scenario . In comparison to other sites across the United States , this scenario is at the high - end of vulnerability , with a sandy, acidic soil in which saflufenacil

### 17

residues might be highl y mobile and relativel y persistent. Exposure to residues in areas of less sandy soils is expected to be less than is estimated with this scenario. Modifications to the Delmarva corn scenario include a lengthening of the minimum depth of evaporation to 17.5 cm in order to be consistent with the PRZM - 3 User’s Manual (Suarez, 2006) and adjusting the crop - specific inputs (emergence, maturity, and harvest dates and post harvest foliar flag) to values that do not reflect the presence of a crop. Bulk density , field capacity , wilting point, and percent organi c carbon values were updated to reflect current values reported in the United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Soil Data Mart report for map unit EvB (map unit EvA, which was used for the corn scenario, was not listed; USDA, 2009) and the Soil Characterization Database (USDA, 2009a). The remaining values of the provisional Delmarva non - ag scenario are consistent with those of the Delmarva corn scenario. **Table 8. PRZM GW**  **scenario input**  **parameters (Delma**  **rva non -**  **ag provisional**  **scenario) .**  **Input Parameter Value**  **Comments Source**  Meteorological file W93721 Represents the meteorology of Baltimore, Maryland from 1961 to 1990. USEPA, 2009b Pan Evaporation Factor 0.77 Value from PRZM - 3 Manual, Figure 5.9 Suarez, 2006 Snow Melt Factor 0.5 Value in the typical range for open areas. Suarez, 2006 Minimum Depth of Evaporation (cm) 17.5 Value from PRZM - 3 Manual, Figure 5.2 Suarez, 2006 Root Depth (cm) 100 Estimated value (estimate ) Canopy Coverage (%) 90 Estimated value ( estimate ) Canopy Water Holdup (cm) 0.15 Estimated value consistent with PRZM - 3 Manual, Table 5.4 (estimate) Post -harvest Foliar Residue Flag 3 Foliar residues remain on foliage. (none) Emergence Date Jan. 1 st Values are not applicable to non - cropped areas. (none) Maturity Date Jan. 2 nd Harvest Date Dec. 31 st Irrigation None Irrigation was not simulated . (none) Bulk Density ( 0 - 0.1 m)

(0.1 - 10 m) 0.78 g/mL

1.7 g/mL Midpoint of values reported in the NRCS

Soil Data Mart for Evesboro soils USDA, 2009 Field Capacity (0 - 9 m) 0.075 Estimated value consistent with the NRCS Soil Characterization Database USDA, 2009a Wilting Point (0 - 9 m) 0.01 Estimated value consistent with the field capacity minus the available water capacity reported in the NRCS Soil Data Mart for Evesboro soils USDA, 2009 Percent Organic ( 0 - 0.1 m) Carbon (0.1 - 10 m) 42 0.25 Midpoint of values reported in the NRCS Soil Data Mart for Evesboro soils USDA, 2009

### 18

**3.3.3. Modeling Results**  Screening estimates generated for drinking water exposure assessment are listed in **Table 9**  . The proposed use pattern for the SharpenTM formulation for use on tree plantations and non agricultural areas was the maximum use pattern modeled for surface water and ground water exposure estimates, as described above. Mo deled e stimates are 1 - in - 10 - ye ar peak and 1 - in - 10 - ye ar annual mean values. The 30 - ye ar dail y time series of EDWCs that the Tier II point estimates for ground water represent will be delivered with this assessment to HED for probabilistic modeling in support of human health dietary risk assessment. Model input/output data and filenames for these estimates are attached in **Appendix I I**  . **Table 9**  **. Drinking Wate**  **r Exposure Estimates for the Proposed Maximum Use Pattern**  **s of**  **Saflufenacil ,**  **Tree Plantations and Non**  **- agricultural Areas**  **. Source**  **(Tier: Model) 1**  **- in**  **- 10**  **- year Peak**  **Exposure (μg/L) 1**  **- in**  **- 10**  **- year Annual**  **Mean Exposure (μg/L)** Surface water (Tier I: FIRST) 37. 3 23. 8 Ground water (Tier I: SCI - GROW) ≤ 1 ,100 A Ground water (Tier II: PRZM GW) 180 173 A Ground water concentrations calculated by SCI - GROW are the highest 9 0 - day running average . 

### Exposure estimates for total residues in surface water include a 1 - in - 10 - ye ar p eak of 37.3 μg/L and a 1 - in - 10 - ye ar annual average of 23.8 μg/L. The Tier I screening EDWC for total residues in ground water wa s 1.1 mg/L (ppm). This value i s uncertain because it is based on model inputs that are outside the ranges of values used to develop the model ( KOC 

### range of 32 to 180 L/kg; aerobic soil metabolism half - life range of 13 to 1000 days; USEPA, 2002). Tier II screening EDWCs were generated for ground water because the Tier I value was expected to result in chronic dietary risk exceedances, when considering food plus drinking water (personal communication with George Kramer, HED; Apr. 6, 2009). Based on the PRZM GW model, the Tier II screening EDWC s in ground water for use in dietary risk assessment are 180 μg/Lfor acute exposure and 173 μg/L for chronic exposure . **Figure 2** displays EDWCs in ground water simulated with PRZM GW over 30 years.

### 19

**Figure 2. Exposure estimates of saflufenacil in Delmarva**  **ground water over thirty years ,**  **generated with PRZM GW and a**  **provisional non**  **- agricultural scenario**  **. 3.3.4.**  **Drinking Water Treatment** The Office of Pesticide Programs (OPP) does not have direct data on the effects of drinking water treatment on saflufenacil . Flocculation and sedimentation removal may be effective at reducing saflufenacil concentrations. Carbon filtering may also reduce saflufenacil concentrations due to the compound’s moderate affinity to organic carbon. Because of the absence of data on saflufenacil , the effects of drinking water treatment were not con sidered in this assessment. **4. CONCLUSIONS**  Screening drinking water exposure estimates for proposed saflufenacil use s on selected row crops, orchard trees, vineyards, tree plantations, and non - agricultural areas are represented by the maximum use pattern on tree plantations and non - agricultural areas ( **Tables 1 and 9**  ). The total residues of concern of saflufenacil include saflufenacil parent , M01, M02, M07, M08, M15, M22, and Product 8, all of which are assumed to have similar toxicity to saflufenacil parent. Exposure estimates in ground water ( 173 - 180 μg/L) may be higher than those in surface water ( 24 - 37 μg/L).

0 20 40 60 80 100 120 140 160 180 200

1/ 1/ 1961 6/ 24/ 1966 12/ 15/ 1971 6/ 6/ 1977 11/ 27/ 1982 5/ 19/ 1988 **Da te** **E D** **W C** **( p** **p b** **)**

### 20

**5. LITERATURE CITATIONS**  Effland, W. R., N. C. Thurman, I. Kennedy. 1999. Proposed Methods for Determining Watershed - derived Percent Crop Areas and Considerations for Applying Crop Area Adjustments to Surface Water Screening Models. Presentation to the FIFRA Science Advisory Panel, May 27, 1999. Online at: http://www.epa.gov/scipoly/sap/meetings/1999/052599_mtg.htm Jones, R. D., S. Abel, W. R. Effland, R. Matzner, R. Parker. 1998. An Index Reservoir for Use in Assessing Drinking Water Exposure. Proposed Methods for Basin - scale Estimation of Pesticide Concentrations in Flowing Water and Reservoirs for Tolerance Re assessment. Presentation to FIFRA Science Advisory Panel , June 29 - 30, 1998. Online at: http://www.epa.gov/scipoly/sap/meetings/1998/072998_mtg.htm Suarez, L. 2006. PRZM - 3, A Model for Predicting Pesticide and Nitrogen Fate in the Crop Root and Unsaturated Soil Zones: Users Manual for Release 3.12.2. Revision A. EPA/600/R- 05/111 . September , 2006. United Nations. 1998. Kyoto Protocol to the United Nations F ramewo rk Convention on Climate Change. Online at: http://unfccc.int/resource/docs/convkp/kpeng.pdf United States Department of Agriculture (USDA). 2009. Soil Data Mart . U.S. Department of Agriculture , Natural Resources Conservation Service . Online at: http://soildatamart.nrcs.usda.gov/ USDA. 2009a . Soil Characterization Database. U.S. Department of Agriculture, Natural Resources Conservation Service . Online at: http://ssldata.nrcs.usda.gov/ United States Environmental Protection Agency (USEPA) . 2002. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesti cides. U.S. Environmental Protection Agency , Office of Pesticide Programs, Environmental Fate and Effects Divis ion. Feb. 28, 2002. Online at: http://www.epa.gov/oppefed1/models/water/input_guidance2_28_02.htm USEPA. 2002a. SCI - GROW User’s Manual. U.S. Environmental Prot ection Agency , Office of Pesticide Programs, Environmental Fate and Effects Division . Nov. 1, 2001; revised Aug. 23, 2002. USEPA. 2005 . N - Methyl Carbamate Pesticide Cumulative Risk Assess me nt: Pilot Cumulative Analysis. Docket Number: OPP - 2004 - 0405 . Feb. 15 - 18 , 2005. USEPA. 2005a . Preliminary N - Methyl Carbamate Cumulative Risk Assessment. Docket Number: OPP - 2005 - 0172 . Aug. 23 - 26, 2005. USEPA. 2006. Standardized Soil Mobility Classification Guidance. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division, Memorandum. Apr. 21, 2006. USEPA. 2008. FIRST User’s Manual. Version 1.1.1. U.S. Environmental Prot ection Agency , Office of Pesticide Programs, Environmental Fate and Effects Division . Mar. 26, 2008. USEPA. 200 9 . Ingredient: Saflufenacil. Report of the Residues of Concern Knowledgebase Subcommittee (ROCKS). U.S. Environmental Prot ection Agency , Office of Prevention, Pesticide s, and Toxic Substances, Health Effects Divis ion. Internal memorandum. Jan. 6 , 2009 . U SEPA. 2009a. Water Models. U.S. Environmental Protection Agency, Pesticides: Science and Policy , Models and Databa ses. Last updated Mar. 23, 2009. Online at: http://www.epa.gov/oppefed1/mo dels/water/ USEPA. 2009b. Meteorological Data. U.S. Environmental Protection Agency , Center for Exposure Assessment Modeling . Last Updated Dec. 23, 2008. Online at: http://www.epa.gov/ceampubl/tools/metdata/index.html

### 21

United States National Institutes of Health (USNIH ) . 2009. Hazardous Substances Data Bank. United States National Institutes of Health, National Library of Medicine, Specialized Information Services, Environmental Health and Toxicology, Toxicology Data Network (TOXNET®) , Hazardous Substances Data Bank (HSDB®). Last updated: Jun. 12, 2008. Online at: http://toxnet.nlm.nih.gov/ 

### 5.1. **Submitted Environmental Fate**  **Studies** MRID 47127817. Beery, J. BAS 800 H: Dissociation Constant. Unpublished amended study performed , sponsored and submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Protocol ID.: F200524 . Feb. 14, 2006. MRID 47127818. Vanhook, C. BAS 800 H: Partition Coefficient (n - Octanol/Water) Estimation by High Performance Liquid Chromatography. Unpublished study performed, sponsored , and submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Protocol ID.: 1 32458 . Dec. 13, 2005. MRID 47127819. Vanhook, C. BAS 800 H: Water Solubility at 20°C by Shake Flask Method. Unpublished study performed, sponsored, and submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Protocol ID.: 132452a . Dec. 2, 2005. MRID 47127821. Kroehl, T. BAS 800 H

– Reg.No. 4054449 : Physical Properties of the Pure Active Ingredient. Unpublished study performed by BASF Aktiengesellschaft, Limburgerhof, Germany; submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Report Number: 132464 - 1 . Sep. 30, 2005. MRID 47127822. Paulick, R. Determination of the Henry’s Law Constant for BAS 800 H at 25°C. Unpublished study performed, sponsored, and submitted by BASF Corporation, Research Triang le Park, North Carolina. BASF Registration Document Number: 2007/7013512 . Dec. 26, 2007. MRID 47127823. Panek, M. 2006. Hydrolysis of 14 C - BAS 800 H. Unpublished study performed, sponsored, and submitted by BASF Corporation, Research Triangle Park, N orth Carolina. BASF Reg. Doc. No.: 2005/7004259. BASF Study No.: 132680. Oct. 10, 2006. MRID 47699901. Ta, C., and J. Trollinger. 2009. Aqueous photolysis of 14C - BAS 800 H. Unpublished amended study performed, sponsored, and submitted by BASF Corpo ration, Research Triangle Park, North Carolina . Study Protocol ID : 132683. Nov. 9, 2007. MRID 47127825. Ta, C. 2007. BAS 800 H: Soil photolysis. Unpublished amended study performed, submitted, and sponsored by BASF Corporation, Research Triangle Park , North Carolina. Study Protocol ID: 132653. Nov. 13, 2007. MRID 47445901. Singh, M. 2008. Aerobic soil metabolism of 14 C - BAS 800 H on US soils. Unpublished amended study performed , sponsored , and submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Protocol ID.: 132650. May 30, 2008. MRID 47611201 . Panek, M. and A. Pyles. 2008. Anaerobic soil metabolism of 14 C - BAS 800 H. Unpublished study performed, sponsored , and submitted by BASF Corporation, Research Triangle Park, North Carolina. BASF Study No.: 332554. Dec. 15, 2008. MRID 47127828. Panek, M. 2007 . Anaerobic aquatic metabolism of 14C - BAS 800 H. Unpublished study performed by BASF Agro Research, Research Triangle Park, North Carolina and Agvise Laboratories, Northwood, North Dakota; sponsored and submitted by BASF Corporation, Research Triangle Park, North Carolina. Study Protocol ID.: 1326470. Oct. 18, 2007. MRID 47127827. Malinsky, D.S. 2008. Aerobic aquatic metabolism of 14 C - BAS 800 H under dark and light conditions. Unpublished study performed by BASF Agro Research, Research Triangle Park, North Carolina and Agvise Laboratories, Northwood, North Dakota; sponsored and submitted by BASF Corporation, Research Triangle Park, N orth Carolina. BASF No.: 133487. Jan. 4, 2008.

### 22

MRID 47127829. Ta, C.T. and J. R. Varner. 2007. Adsorption/desorption of BAS 800 H on soils. Unpublished study performed, sponsored, and submitted by BASF Corporation , Research Triangle Park, NC . BASF Study Number: 132674. Jul. 17, 2007. MRID 47127830. Ta, C.T. 2007. Adsorption/desorption of the major metabolites (M800H01, M800H02, M800H07, M800H08, M800H15, and M800H22) of BAS 800 H on soils. Unpublished study performed, sponsored, and submitted by BASF Corporation, Research Triangle Park, NC. Study No. 132677. Nov. 19, 2007. MRID 47127834. Jordan , J.M., M.G. Saha, and R.L. Warren. 2007. Terrestrial field dissipation of BAS 800 H in pine/vegetation management use patterns. Unpublished study performed by BASF Agro Research, Research Triangle Park, North Carolina, Agvise Laboratories, Inc., Northwood, North Dakota (soil characterization), and Research Options, Inc., Montezuma, Georgia (field phase); sponsored and submitted by BASF Agro Researc h, Research Triangle Park, North Carolina. BASF Study No.: 132665. Dec. 7, 2007. MRID 47127835. Jordan , J., M.G. Saha, and R. Warren. 2008. Terrestrial field dissipation of BAS 800 H in row crop use patterns. Unpublished study performed by BASF Agro Research, Research Triangle Park, North Carolina, Mid - South Ag Research, Proctor, Arkansas (field phase), Alvey Agricultural Research, Carlyle, Illinois (field phase), ICMS, Inc., Portage la Prairie, Canada (field phase), and Agvise Laboratories, Inc., No rthwood, North Dakota (soil characterization), and sponsored and submitted by BASF Agro Research, Research Triangle Park, North Carolina. BASF Study No.: 132668. Jan. 8, 2008. MRID 47127836. Jordan, J., M.G. Saha, and R. Warren. 2007. Terrestrial fi eld dissipation of BAS 800 H in orchard and vineyard use patterns. Unpublished study performed by BASF Agro Research, Research Triangle Park, North Carolina, Qualls Agricultural Research, Ephrata, Washington (field phase), Vaughn Agricultural Research Services, Branchton, Ontario, Canada (field phase), Research for Hire, Porterville, California (field phase), and Agvise Laboratories, Inc., Northwood, North Dakota (soil characterization), and sponsored and submitted by BASF Agro Research, Research Triangle Park, North Carolina. BASF Study No.: 134549. Dec. 19, 2007.

### 23

**Appendix I. Chemical**  **Names, Structures**  **, and Maximum Reported Amounts of**  **Saflufenacil and Its Degradates.**  **Table I.1**  **. Saflufenacil and Its Major Organic Environmental Degradates. Code Name/**  **Synonym Chemical Name**  **Chemical Structure Study Type**  **Maximum %AR (day)**  **Final %AR**

**(study length) PARENT**  

### Saf **lufenacil BAS 8**  **00H IUPAC:**  N ′ - {2 - Chloro - 4 - fluoro - 5 -

[1,2,3,6 - tetrahydro - 3 - methyl - 2,6 - dioxo - 4 - (trifluoromethyl)pyrimidin 1 - yl]benzoyl} -N - isopropyl -N methylsulfamide **CAS:** 2 - Chloro - 5 - [3,6 - dihydro - 3 - methyl - 2,6 - dioxo - 4 - (trifluoromethyl) - 1(2H) - pyrimidinyl] - 4 - fluoro -N - [[methyl(1 - methylethyl)amino] sulfonyl]benzamide **CAS -**  **no:** 372137 - 35 - 4 **Formula:** C 17 H 17 ClF 4N4 O 5 S **MW :**  500.86 g/mol O N H S N C H 3 C H 3 O O N C H 3

F O N O C H 3

Cl F F F

**MAJOR (>10%) TRANSFORMATION PRODUCTS** 

### M **01 M800**  **H01** N’ - [2 - Chloro - 4 - fluoro - 5 - (3 - methyl 2,6 - dioxo - 4 - (trifluoromethyl) - 3,6 - dihydro - 1(2H) - pyrimidinyl)benzoyl] -N’ - isopropylsulfamide **Formula:** C 16 H 15 ClF 4N4 O 5 S **MW :**  486.83 g/mol Aerobic soil **10** (57) 1.3 (330) Anaerobic soil **14** ( - 3, 34 ) 10 (75) Soil photolysis 5.4 (14) nd 1 (30) Aqueous photolysis not detected Hydrolysis not identified Aerobic aquatic not detected Anaerobic aquatic not identified Field studies 0.02 ppm (0 - 8, 11, 20) nd 1 (124, 271, 360) 

### M **02 M800**  **H02** N’ - [2 - Chloro - 5 - (2,6 - dioxo - 4 -

(trifluoromethyl) - 3,6 - dihydro 1(2H) - pyrimidinyl) - 4 - fluorobenzoyl] -N - isopropyl -N methylsulfamide **Formula:** C 16 H 15 ClF 4N4 O 5 S **MW :**  486.83 g/mol O N H S N C H 3 C H 3 O O N C H 3

F O N H O

Cl F F F Aerobic soil **30** (246) 17 (330) Anaerobic soil **24** (75) 24 (75) Soil photolysis not detected Aqueous photolysis not detected Hydrolysis not identified Aerobic aquatic not detected Anaerobic aquatic not identified Field studies 0.01 ppm (0 - 2, 6) nd 1 (360) O N H S N H C H 3 O O N C H 3

F O N O C H 3

Cl F F F

### 24

**Code Name/ Synonym**  **Chemical Name Chemical Structure**  **Study Type Maximum**  **%AR (day) Final %AR** 

**(study length) M04**  **M800H04 Formula:**  C 17 H 19 ClF 4N4 O 6 S

**MW :**  518.87 g/mol O N H S N C H 3 C H 3 O O N H C H 3

F O N O C H 3

Cl F F F O H Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aq. photolysis - pH5 Aq. photolysis - pH7 4.1 ( 20 ) 5.4 (10) 4.1 ( 20 )

1.8 (21) Hydrolysis - pH7 Hydrolysis - pH9 0.95 (30) **13** (3) 0.95 (30)

nd 1 (30) Aerobic aquatic not identified Anaerobic water Anaerobic sediment Anaerobic system 4.4 (62) 0.5 (62) 4.4 (62) nd 1 (364)

nd 1 (364) nd 1 (364) Field studies not analyzed 

### M **07 M800**  **H07** N - {4 - Chloro - 2 - fluoro - 5 -

[({[isopropyl (methyl) amino] sulfonyl} amino) carbonyl] phenyl} -N’ - methylurea **Formula:** C 13 H 18 ClFN4 O 4 S **MW :**  380.83 g/mol O N H S N C H 3 C H 3 O O N H C H 3

F N H C H 3 O

Cl Aerobic soil **52** (25) 7.2 (330) Anaerobic soil 4.4 (60) 1.5 (75) Soil photolysis **19** (14) 2.3 (30) Aq. photolysis - pH5 Aq. photolysis - pH7 8.6 (20) 9.5 (15 ) 8.6 (20)

8.2 (21) Hydrolysis

–

pH7 Hydrolysis

–

pH9 9.2 (30)

**77** (30) 9.2 (30)

77 (30) Aerobic water Aerobic sediment Aerobic system **20** (30) 3.7 (60) **23** (60) 19 (60)

3.7 (60) 23 (60) Anaerobic water Anaerobic sediment Anaerobic system **62** (364) **13** (91) **71** (91) 62 (364)

6.7 (364) 68 (364) Field studies 0.02 ppm (11, 20, 44) nd 1 (124, 271) 

### M **08 M800**  **H08** N’ - [2 - Chloro - 4 - fluoro - 5 - (3 - methyl 2,6 - dioxo - 4 - (trifluoromethyl) tetrahydro - 1(2H) - pyrimidinyl) benzoyl] -N - isopropyl -N methylsulfamide **Formula:** C 17 H 19 ClF 4N4 O 5 S **MW :**  502.88 g/mol Aerobic soil **66** (246) 41 (330) Anaerobic soil **25** (18) 18 (75) Soil photolysis **19** (22) 18 (30) Aqueous photolysis not detected Hydrolysis not identified Aerobic aquatic not detected Anaerobic aquatic not identified Field studies 0.05 ppm (1, 6) nd 1 (124, 360) O N H S N C H 3 C H 3 O O N C H 3

F O N O C H 3

Cl F F F

### 25

**Code Name/ Synonym**  **Chemical Name Chemical Structure**  **Study Type Maximum**  **%AR (day) Final %AR** 

**(study length) M15**  **M800H15** N - {4 - Chloro - 2 - fluoro - 5 -

[({[isopropyl (methyl) amino] sulfonyl} amino) carbonyl] phenyl} - 4 - 4 - 4 - trifluoro - 3,3 - dihydroxybutanamide **Formula:** C 15 H 18 ClF 4N 3 O 6 S **MW :**  479.84 g/mol O N H S N C H 3 C H 3 O O N H C H 3

F O

Cl F F F O H O H Aerobic soil not identified Anaerobic soil 1.6 (18) nd 1 (75) Soil photolysis 9.6 (30) 9.6 (30) Aq. photolysis - pH5 Aq. photolysis - pH7 2.3 (20) 1 .3 (10) 2.3 (20)

n d 1 (21) Hydrolysis

–

pH7 Hydrolysis

–

pH9 2.3 (30)

**22** (30) 2.3 (30)

22 (30) Aerobic aquatic not detected Anaerobic water Anaerobic sediment Anaerobic system **17** (62 - 91) 0.9 (273) **17** (62 - 91) 7.1 (364)

0.8 (364) 7.6 (364) Field studies not detected 

### M22 **M800H22** 3 - [({4 - Chloro - 2 - fluoro - 5 -

[({[isopropyl(methyl)amino]sulfon yl}amino)carbonyl]anilino}carbony l)(methyl)amino] - 4,4,4 - trifluorobutanoic acid **Formula:** C 17 H 21 ClF 4N4 O 6 S **MW :**  520.89 g/mol O N H S N C H 3 C H 3 O O N H C H 3

F N O C H 3

Cl F F F O O H Aerobic soil **16** (43) 7.1 (334) Anaerobic soil 1.6 (60) 0.2 (75) Soil photolysis not detected Aqueous photolysis not detected Hydrolysis not identified Aerobic aquatic not detected Anaerobic aquatic not identified Field studies not detected 

### M26 **M800H26** N - Methyl - 2,2,2 - trifluoroacetamide

**Formula:** C 3 H 4 F 3 NO **MW :**  127.07 g/mol N H O F F F C H 3 Aerobic soil **18** (25) nd 1 (334) Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed

### 26

**Code Name/ Synonym**  **Chemical Name Chemical Structure**  **Study Type Maximum**  **%AR (day) Final %AR** 

**(study length) M29**  **M800H29 TFA**  **(also formulated**  **as TFA, sodium salt)**  Trifluoroacetic acid

**Formula:** C 2 HF 3 O 2 **MW :**  114.02 g/mol O H O F F F Aerobic soil not identified but not quantified Anaerobic soil 6.9 (0) 3.7 (75) Soil photolysis not identified Aq. photolysis - pH5 Aq. photolysis - pH7 4.0 (20) **29** (21) 4.0 (20)

29 (21) Hydrolysis not identified Aerobic water Aerobic sediment Aerobic system 6.9 (60) 2.0 (51 - 60) 8.8 (60) 6.9 (60)

2.0 (60) 8.8 (60) Anaerobic water Anaerobic sediment Anaerobic system 9.2 (364) 3.6 (91) **11** (364) 9.2 (364)

1.9 (364) 11 (364) Field studies not analyzed 

### M31 **M800H31** 3 - [Carboxy(methyl)amino] - 4,4,4 -

trifluorobutanoic acid **Formula:** C 6 H 8 F 3 N O 4 **MW :**  215.13 g/mol O H N O C H 3 F F F O O H Aerobic soil **18** (43) 8.7 (334) Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M33 **M800H33** 1,1,1 - Trifluoroacetone

**CAS -**  **no:** 421 - 50 - 1 **Formula:** C 3 H 3 F 3 O **MW :**  112.05 g/mol C H 3 O F F F Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aq. photolysis - pH5 Aq. photolysis - pH7 3.2 (20) **2 0**  (15 ) 3.2 (20)

17 (21) Hydrolysis

–

pH7 Hydrolysis

–

pH9 4.7 (30)

**74** (21) 4.7 (30)

73 (30) Aerobic water Aerobic sediment Aerobic system **23** (7) nd 1 **23** (7) 3.2 (60)

nd 1 3.2 (60) Anaerobic water Anaerobic sediment Anaerobic volatiles Anaerobic system **15** (62) 0.9 (62) **13** (160 - 364) **25** (62) nd 1 (364)

nd 1 (364) 13 (364) 13 (364) Field studies not analyzed

### 27

**Code Name/ Synonym**  **Chemical Name Chemical Structure**  **Study Type Maximum**  **%AR (day) Final %AR** 

**(study length) TFP**  1,1,1 - Trifluoro - 2 - propanol

**CAS -**  **no:** 374 - 01 - 6 **Formula:** C 3 H 5 F 3 O **MW :**  114.07 g/mol Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic water Anaerobic sediment Anaerobic volatiles Anaerobic system **16** (62) 3.4 (62) **24** (160 - 364) **30** (62) 0.4 (364)

nd 1 (364) 24 (364) 24 (364) Field studies not analyzed 

### Product 8 **Formula:** C 17 H 15 ClF 4N4 O 6 S

**MW :**  516.86 g/mol O N S N H C H 3 O O N C H 3

F O N O C H 3

Cl F F F

O H Aerobic soil not identified Anaerobic soil not identified Soil photolysis **17** (15) 17 (15) Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### Unknown **3/2/2** Unknown compound with tR 3 .9

min that formed under irradiated conditions in the aque ous photolysis study, including unknowns 2 (phenyl - labeled) in the pH5 study and unknowns 3 (phenyl - labeled) and 2 (uracil labeled) in the pH7 study. Unknown Aq. photolysis - pH5 Aq. photolysis - pH7 1.0 (20) **9.5** (21) 1.0 (20)

9.5 (21)

1 “nd ” means that the compound was not detected. C H 3 O H F F F

### 28

**Table I .2**  **. Minor Organic Environmental Degradates of Saflufenacil. Code**  **Chemical name Chemical structure**  **Study Type Maximum**  **%AR (day) Final %AR** 

**(study length) M06**  **M800H06** N - [2 - Chloro - 4 - fluoro - 5 - (3 - methyl 2,6 - dioxo - 4 - (trifluoromethyl)tetrahydro - 1(2H) - pyrimidinyl)benzoyl] -N’ - isopropylsulfamide **Formula:** C 16 H 17 ClF 4N4 O 5 S **MW :**  488.85 g/mol O N H S N H C H 3 O O N C H 3

F O N O C H 3

Cl F F F Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M11 **M800H11** N’ - [2 - Chloro - 5 - (2,6 - dioxo - 4 -

(trifluoromethyl) - 3,6 - dihydro - 1(2H) - pyrimidinyl) - 4 - fluorobenzoyl] -N isopropylsulfamide **Formula:** C 15 H 13 ClF 4N4 O 5 S **MW :**  472.81 g/mol Aerobic soil not analyzed Anaerobic soil not identified Soil photolysis not analyzed Aqueous photolysis not analyzed Hydrolysis not analyzed Aerobic aquatic not detected Anaerobic aquatic not analyzed Field studies not analyzed 

### M16 **M800H18** 2 - Chloro - 4 - fluoro -N - {isopropyl

(methyl) - amino] sulfonyl} - 5 - [(4,4,4 - trifluoro - 2,3 - dihydroxybutanyl) amino] benzamide **Formula:** C 15 H 18 ClF 4N 3 O 6 S **MW :**  479.84 g/mol Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic water Anaerobic sediment Anaerobic system 8.4 (364) 0.9 (273 - 364) 9.3 (364) 8.4 (364)

0.9 (364) 9.3 (364) Field studies not analyzed 

### M18 **M800H18** 2 - Chloro - 4 - fluoro -N -

[(isopropylamino) sulfmony] - 5 - {[(methylamino) carbonyl] amino} benzamide **Formula:** C 12 H 16 ClFN4 O 4 S **MW :**  366.80 g/mol Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic water Anaerobic sediment Anaerobic system 6.2 (273) 0.9 (364) 7.0 (273) 6.0 (364)

0.9 (364) 6.7 (364) Field studies not analyzed O N H S N H C H 3 O O N C H 3

F O N H O

Cl F F F

O N H S N C H 3 C H 3 O O N H C H 3

F O Cl F F F O H O H

O N H S N H C H 3 O O N H C H 3

F N H C H 3 O

Cl

### 29

**Code Chemical name**  **Chemical structure Study Type**  **Maximum %AR (day)**  **Final %AR**

**(study length) M24**  **M800H24** (2E) - 3 - ({[4 - Chloro - 2 - fluoro - 5 -

({[(methylamino)sulfonyl] amino}carbonyl)aniline]carbonyl}ami no) - 4,4,4 - trifluoro - 2 - butenoic acid **Formula:** C 13 H 11 ClF 4N4 O 6 S **MW :**  462.77 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M25 **M800H25** 2 - Chloro - 4 - fluoro - 5 - (3 - methyl - 2,6 -

dioxo - 4 - (trifluoromethyl) - 3,6 - dihydro - 1(2H) - pyrimidinyl)benzamide **Formula:** C 13 H 8 ClF 4N 3 O 3 **MW :**  365.67 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aq. photolysis - pH5 Aq. photolysis - pH7 2.9 (20) 1.8 (15) 2.9 (20)

1.3 (21) Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M27 **M800H27** N - [2 - Chloro - 5 - (2,6 - dioxo - 4 -

(trifluoromethyl)tetrahydro - 1(2H) - pyrimidinyl) - 4 - fluorobenzoyl] -N’ - isopropylsulfamide **Formula:** C 15 H 15 ClF 4N4 O 5 S **MW :**  474.82 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M28 **M800H28** N - [2 - Chloro - 4 - fluoro - 5 - (3 - methyl 2,6 - dioxo - 4 - (trifluoromethyl)tetrahydro - 1(2H) - pyrimidinyl)benzoyl] -N’ - methylsulfamide **Formula:** C 14 H 13 ClF 4N4 O 5 S **MW :**  460.79 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed O N H S N H C H 3 O O N H F N H O

Cl F F F O O H

O N H 2

N O N O C H 3

Cl F F F F O N H S N H C H 3 O O N C H 3

F O N H O

Cl F F F

O N H S N H C H 3 O O N F O N O C H 3

Cl F F F

### 30

**Code Chemical name**  **Chemical structure Study Type**  **Maximum %AR (day)**  **Final %AR**

**(study length) M30**  **M800H30** 2 - Chloro - 4 - fluoro - 5 - (3 - methyl - 2,6 -

dioxo - 4 - (trifluoromethyl)tetrahydro 1(2H) - pyrimidinyl)benzamide **Formula:** C 13 H 10 ClF 4N 3 O 3 **MW :**  367.69 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### M35 **M800H35** N - [4 - Chloro - 2 - fluoro - 5 -

({[(isopropylamino) sulfonyl] amino} carbonyl) phenyl] urea **Formula:** C 11 H 14 ClFN4 O 4 S **MW :**  352.77 g/mol Aerobic soil identified but not quantified Anaerobic soil not identified Soil photolysis not identified Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not detected Anaerobic aquatic not identified Field studies not analyzed 

### Product 3 2 - Chloro - 5 - [2,6 - dioxo - 4 -

(trifluoromethyl) - 3,6 - dihydropyrimidin - 1(2H) - yl] - 4 - fluorobenzamide **Formula:** C 12 H 6 ClF 4N 3 O 3 **MW :**  351.65 O N H 2 N F O N H O

Cl F F F Aerobic soil not identified Anaerobic soil not identified Soil photolysis 9.2 (30) 9.2 (30) Aqueous photolysis not identified Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed 

### Hydroxyl **methyl degradate**  2 - Chloro - 5[4 - difluoro(hydroxyl)

methyl] - (3 - methyl - 2,6 - dioxo - 3,6 - dihydropyrimidin - 1(2H) - yl -N - {[isopropyl(methyl)amino]sulfonyl} benzamide **Formula:** C 17 H 19 ClF 2N4 O 6 S **MW :**  480.88 g/mol O N H S N C H 3 C H 3 O O N C H 3

O N O C H 3

Cl O H F F Aerobic soil not identified Anaerobic soil not identified Soil photolysis not identified Aq. photolysis - pH5 Aq. photolysis - pH7 5.3 (10 ) 3.3 (15 ) 2.5 (20)

1.0 (21) Hydrolysis not identified Aerobic aquatic not identified Anaerobic aquatic not identified Field studies not analyzed O N H 2 N F O N O C H 3

Cl F F F

O N

H S N H C H 3 O O N H C H 3

F N H 2 O

Cl

### 31

**Appendix II. Model Input/Output Data.**  **Table II.1. Summary of Input/Output Files. File name**  **Date Location/Simulation**  **Input/Output F ile**  **for FIRST**  Saf4.fir Apr. 2, 2009 National screen

**Input/Output File for**  **SCI -**  **GROW** Saf.sci Apr. 8, 2009 National screen **Input File for**  **PRZ M GW**  Saf - nonag 4 - 9 - 09.PGI Apr. 9, 2009 Delmarva non - agricultural area **Crop Scenario File**  **for PRZM GW** Delmarva non - ag 4 - 9 - 09.SCN Apr. 9, 2009 Delmarva non - agricultural area **Weather Data File**  **for PRZM GW** W93 721 .dvf Jul. 3, 2002 Baltimore, MD 

### Example Input/ **Output Data for Individual Simulations FIRST Input/Output File.**  RUN No. 1 FOR Saflufenacil ON Non - ag * INPUT VALUES *

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

-------------------------------------- ------------------------------ 0.356( 0.356) 1 1 5.9 2100.0 AERIAL(16.0) 100.0 0.0 FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

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

-------------------------------------------------------------------- 6833.00 2 0.00 90.90 - 11271.60 ****** 1122.78 UNTREATED WATER CONC (MICROGRAMS/LITER (PPB)) Ver 1.1.1 MAR 26, 2008

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

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

37.341 23.847

### 32

**SCI -**  **GROW Input/Output File.** SciGrow version 2.3 chemical:Saflufenacil time is 4/ 2/2009 17: 0:21

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

------------------------------------- ----------------------------------- 0.356 1.0 0.356 0.00E+00 1627.0

------------------------------------------------------------------------ groundwater screening cond (ppb) = 5.08E+03 ****************************** ****************************************** 

### PRZM GW **Input File.**  Saflufenacil 10000 1627 5.87 1 1 6 7 8 9 10 7 8 9 10 15 7 3 4 5 5 5 9 10 11 11 12 0.4 4 2.0 2.1 .987 .0001234 33 34 35 36 .009765632 2 1

### 33

1 1 1 2 2 1 1 1 1 Delmarva C: \ Models \ Inputs \ Metfiles \ w93721.dvf 0.77 0.5 17.5 100 90 0.15 1 1 2 1 31 12 3 1 66 67 68 1.515 1.514 1.513 1.512 1.511 1.56 1.509 1.508 1.507 1.506 1.505 1.8 0.15 0.14 0.13 0.12 0.11 0.10 0.09 0.08 0.07 0.06 0.05 0.015 0.014 0.013 0.012 0.011 0.010

### 34

0.009 0.008 0.007 0.006 0.005 1.5 1.4 1.3 1.2 1.1 1.0 0.9 0.8 0.7 0.6 0.5 0.1 0.78 1.7 1.7 1.7 1.7 1.7 1.7 1.7 0.075 0.075 0.075 0.075 0.075 0.075 0.075 0.01 0.01 0.01 0.01 0.01 0.01 0.01 42 0.25 0.25 0.25 0.25 0.25 0.25 0.25