Document ID: EPA-HQ-OPP-2010-1026-0008
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2011-12-07T05:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
                                       
                                   OFFICE OF
                          PREVENTION, PESTICIDES, AND
                               TOXIC SUBSTANCES

	PC Code: 118203
	DP Barcode: 349860

MEMORANDUM	April 15, 2009	

SUBJECT:	Tiered Drinking Water Exposure Assessment for Saflufenacil (Section 3 New Chemical Uses on Agricultural and Non-agricultural Areas).

TO:	Kathryn 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)pyrimidin-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 patterns of five proposed end-use labels with selected uses on row crops, orchard trees, vineyards, tree plantations, and non-agricultural areas (EPA Reg. Numbers pending).  Remaining model input parameters were chosen according 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.  Tiered 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 increasingly soluble in water with increasing pH.  Saflufenacil weakly sorbs to soil (i.e., is mobile to highly mobile in soil) and may readily move into surface water through runoff and/or present a ground water concern, depending on the permeability of the soil.  Low application rates may limit the extent to which the compound runs off into surface water or leaches into ground water.

	Saflufenacil may be moderately persistent in some environments, such as acidic to neutral ground water, and may readily degrade in other environments, such as surficial and alkaline water bodies.  The compound dissipates in the environment through chemical and microbially-influenced degradation and by leaching and is expected to degrade moderately in aerobic soil (half-life of 1-5 weeks), less quickly 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.  Estimates 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 "Product 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 assessed with the screening ground water models SCI-GROW (a Tier I model) and PRZM GW (a Tier II model).

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 by roots and foliage, according to the proposed end-use product label BAS 800 04H FiRoCrop Herbicide.  The compound belongs to the mode-of-action Group 14/Group E, meaning that it inhibits protoporphyrinogen-oxidase (PPO), resulting in membrane damage under light and, ultimately, plant death.  Saflufenacil is proposed for use on broadleaf weeds via pre-plant and pre-emergence applications to cereal small grains, corn, chickpeas, cotton, edible beans, edible peas, lentils, lupine, sorghum, soybeans, 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 formulations of saflufenacil are proposed for registration in the United States.  These 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% imazethapyr 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 (Sharpen(TM); 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 areas (BAS 800 02H; Sharpen(TM)), 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. 

Table 2.  Proposed use patterns for saflufenacil end use products.
Product Label
Active Ingredient (%)
Use
Maximum Single Application Rate
(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 corn[a], 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.

Soybeans (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(R) corn
                                     0.023
                                     0.023
Maximum annual app. rate from all sources: 0.134 lbs saflufenacil/A for Clearfield(R) corn; 0.089 lbs saflufenacil/A for legume vegetables and soybeans.
Application timing: pre-plant or pre-emergence (pre-emergence only for Clearfield(R) corn).
Equipment: ground or aerial.

Legume vegetables (per region)[e]
                                     0.017
                          (Southern peas only: 0.023)
                                     0.017
                          (Southern peas only: 0.023)

Soybeans
                                     0.023
                                     0.023

BAS 781 02H
Saflufenacil (6.24%) and Dimethenamid-P (55.04%)
Field corn[a], 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 with higher organic matter); not so 14 days prior to planting.
Equipment: ground, aerial, or chemigation.

Grain sorghum
                                       
                                       

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 (Sharpen(TM))
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 grown 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, barley, 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 Arizona and California.

   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)-pyrimidinyl)benzoyl]-N-isopropyl-N-methylsulfamide] is nonvolatile, hydrophilic, and mobile to highly mobile in soil, as dissolved in surface water runoff and/or ground water.  The compound dissipates in the environment through chemical and microbially-influenced degradation and by leaching and is expected to degrade moderately in aerobic soil (half-life of 1-5 weeks), less quickly in acidic to neutral water bodies (half-life of 4-10 weeks), and more quickly in alkaline water bodies (half-life of <1 week).  While saflufenacil may readily 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 fate parameters of saflufenacil.
Parameter
Value
Source
                     Selected Physical/Chemical Parameters
Molecular mass
500.86
MRID 47127817
Vapor pressure (extrapolated)
20°C: 3.4 x 10[-17] torr
25°C: 1.5 x 10[-1][6] torr
MRID 47127821
Water solubility (20C)
pH 4: 14 mg/L
pH 5: 25 mg/L
pH 7: 2,100 mg/L
pH 9: nd[A]
MRID 47127819
Henry's Law Constant (25°C)
4.01 x10[-20] atm-m[3]/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 (25C)
pH 5: Stable
pH 7: 248 d
pH 9: 4.93 d
MRID 47127823
Aqueous photolysis half-life (22C)
56 d (buffer; pH 5)
22 d (pond water; pH 7.1)
MRID 47699901
Soil photolysis half-life (22C)
66 d (12-hr light/day)
84 d (continuous irradiation)
MRID 47127825
Aerobic soil metabolism half-life (25C)
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 (25C)
[217 d][B] (loamy sand; pH 5.0-6.0)
MRID 47611201
Anaerobic aquatic metabolism half-life (25C)
[29.4 d][B] (pH 5.5-8.5)
MRID 47127828
Aerobic aquatic metabolism half-life (25C)
70.7 d (dark; pH 5.8-6.7)
3.6 d (12-hr light/day; pH 6.1-8.0)
MRID 47127827
                                   Mobility
Range of Freundlich organic carbon normalized partition coefficients (KFOC)
9.3 - 55 L/kgOC (n=6)
MRID 47127829
                               Field Dissipation
Terrestrial field dissipation half-life (Soil series; texture)
	Georgia:
10.7 d (Fuquay; sandy loam)
MRID 47127834

	Arkansas:
	Illinois:
	Manitoba:
6.25 d (Commerce; silt loam)
11.1 d (Cisne-Huey Complex; silt loam)
35.5 d (Neuhorst; loam)
MRID 47127835

	Washington:
	Ontario:
	California:
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 (14 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 hydrolysis.  The range of solubility in water across pH values indicates 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 only determined for the neutral species at an unreported pH value less than the compound's pKa of 4.41 (MRID 47127818).

	At environmental pH values (initial soil pH values of 5.5-8.0), saflufenacil weakly sorbs to soil (MRID 47127829).  However, the compound displays affinity to organic matter (e.g., the coefficient of variation (CV) across six soils for KFOC (60%) is less than that for KF (97%)).  According to the FAO soil mobility classification scheme, saflufenacil is mobile to highly mobile in soil (KFOC of 9.3 to 55 L/kgOC) and may readily 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 saflufenacil is pH-dependent, as the compound degrades readily in alkaline environments (half-life of 5 days at pH 9) and persists in acidic to neutral conditions (stable at pH 5; half-life of 248 days at pH 7; MRID 47127823).  Major hydrolysis degradates include M04, M07, M15, and M33 (chemical names structures, and maximum formed amounts of all degradates are listed in Table I.1, Appendix I).

	The compound is moderately photolyzed in clear, near-surface water (half-lives of 56 days in a sterile pH 5 buffer and 22 days in unsterile pH 7.1 pond water; MRID 47699901) and on soil (half-lives of 66 days under 12 hours of irradiation per day and 84 days under continuous irradiation followed by conversion to a value reflecting 12 hours of irradiation per day; MRID 47127825).  No major degradates were formed in the sterile pH 5 buffer.  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 analysis.  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, M22, M26, and M31, which were up to 10%, 31%, 52%, 66%, 16%, 18%, and 18% of the applied, respectively.  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 was a reduction product.  Its presence is likely the result of enzymatic (i.e., uracil hydrogenase) activity.

	In anaerobic soil, saflufenacil degraded with a half-life of 217 days in one soil (pH 5.0-6.0; MRID 47611201).  Major degradates included M01, M02, and M08, which were a maximum of 14%, 24%, and 25% of the applied, respectively.  Results of the study are highly uncertain because anaerobic conditions were marginal; the mean redox potential in the post-flood water was -34  88 mV (n=28). 

	In anaerobic aquatic systems, saflufenacil degraded with a half-life of 29.4 days in one system (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, respectively, in the total system.  Results of the study are highly 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 strongly 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 system and significant 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 systems, saflufenacil degraded with a half-life of 70.7 days at pH 5.8-6.7 (MRID 47127827).  The major transformation products were M07, M29, M33, and carbon dioxide, which were a maximum of 23%, 8.8%, 23%, and 11% of the applied, respectively, in the total system.  Results of the study are uncertain because dissolved oxygen concentrations (2.7-5.5 mg/L, corresponding to ~33-65% saturation at 25°C) were less than the typical range (7-10 mg/L) and recoveries of the uracil-labeled systems were highly variable (76% to 114%).  Regardless, redox potentials in the water layer (ranging +150 to +410 mV) indicate that the test system was aerobic.  It is not understood why saflufenacil appears to degrade with shorter half-lives in aerobic terrestrial and anaerobic aquatic systems (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 plots 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 and non-agricultural areas).  Total water input was 122% of the historical average.  Soil samples (0-120 cm depth) were collected through 451 days after treatment.  The mean zero-time concentration of saflufenacil 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 days after treatment.

	For each study, test sites were analyzed for M01, M02, M07, M08, M15, and M22.  In the Georgia sandy loam, M08, M01, and M02 were detected above the LOQ (detections between the LOD and LOQ were not reported).  M08 was detected in the 0-7.5 cm and 7.5-15 cm soil depths at maximum concentrations of 0.04 ppm on the day of treatment (21% of the initial soil concentration of saflufenacil) and 0.05 ppm at 6 days after treatment (26% of the initial soil concentration of saflufenacil), respectively, 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 for use on corn, sorghum, small grain crops, and fallow land.  Total water input at these sites was 97% to 108% of the historical average.  Soil samples (0-120 cm depth) were collected through 360 days after treatment.  The mean zero-time concentrations 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, respectively.  Saflufenacil dissipated in the whole soil profile of each site with respective half-lives of 6.25, 11.1, and 35.5 days.  The compound was detected above the limit of quantitation (LOQ = 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 maximum depth of 0-7.5 cm in the Illinois silt loam soil (0-45 days after treatment), and a maximum depth of 15-30 cm in the Manitoba loam soil (6 days after treatment).

	In the Arkansas silt loam, M08 was the only degradate detected above the LOQ.  In the 0-7.5 cm soil depth, M08 was detected at a maximum concentration 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 only degradate detected above the LOQ.  In the 0-7.5 cm soil depth, M08 was detected at a maximum concentration of 0.03 ppm (21% of the initial soil concentration of saflufenacil) at 30 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 concentration 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 was 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 days 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 maximum application pattern for use on orchard trees.  Total water input at these sites was 131% to 846% of the historical average.  Soil samples (0-120 cm depth) were collected from each site through 20 days after the first treatment, 20 days after the second treatment, and 360 days after the third.  Following the first application, the mean zero-time concentrations 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 days 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 days 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 days following the first application, samples were not analyzed below 15 cm despite the detection of saflufenacil in the 5-15 cm depth at these sampling intervals.  Samples were analyzed 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 only degradate detected above the LOQ.  In the 0-2.5 cm soil depth, M08 was detected at a maximum concentration of 0.02 ppm following the all three applications and was not detected above the LOQ below 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, M08 was detected at a maximum concentration of 0.05 ppm at 1 day after the third application and was not detected above the LOQ below the 5-15 cm depth.  In the 0-2.5 cm soil depth, M01 was detected at a maximum concentration of 0.02 ppm at 10 days after the third application and was not detected above the LOQ below this depth.  In the 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 concentration of 0.02 ppm at 20 days after the third treatment, and M07 and M08 were detected at maximum concentrations of 0.02 ppm and 0.01 ppm, respectively, 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 Degradates

	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 eleven minor 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 demethylation products in the aerobic and anaerobic soil metabolism studies.  Product 8 was a major photodegradate on 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 metabolism and soil photolysis studies.

	Degradates M04, M07, M15, and M22 have a cleaved uracil ring, but remain structurally similar to the parent compound.  M04 was a major hydrolytic product at pH 9 but was not detected 18 days after its peak concentration.  M07 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 aerobic soil metabolism study.

	Degradates M26, M29, M31, M33, and TFP are trifluorinated cleavage products of the uracil ring that were identified in submitted studies.  M29 is trifluoroacetic acid (CASRN: 76-05-1), a degradation product shared by pesticides, 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 hydroxyl 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).

	Fluoroform (trifluoromethane; CASRN: 75-46-7) is a possible terminal product of the trifluorinated degradates of saflufenacil.  According to the Hazardous Substances Data Bank, fluoroform will volatilize from water and soil based on a Henry's Law constant of 0.095 atm-m3/mol and a vapour pressure of 3.5 x 104 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 years and gradually diffuse into the stratosphere with a half-life of 20 years (USNIH, 2009).  As an HFC, fluoroform is included with the greenhouse gases subject to the Kyoto Protocol (United Nations, 1998).

      3.2.5.       Residues of Concern

	The Residues of Concern Knowledgebase Subcommittee (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 (USEPA, 2009).  Because product 8 degrades to M01 during handling and/or analysis, identification of the compound and its inclusion as an analyte 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 was used because degradation studies were not performed on the degradates of concern and their patterns of 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 systems only in order to include M07, which doesn't retain the radiolabel on the uracil ring.

Table 4.  Selected environmental fate parameters of the total residues of concern.
Parameter
Value
Source
                                  Persistence
Hydrolysis half-life (25C)
Stable (pH 5, 7)
MRID 47127823
Aqueous photolysis half-life (22C)
90.9 d (pH 5)
MRID 47699901
Aerobic soil metabolism half-life (25C)
9613 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 (25C)
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/kgOC
M02: NC[A] - 41 L/kgOC
M07: 3.3 - 111 L/kgOC
M08: 4.8 - 20 L/kgOC
M15: 9.6 - 57 L/kgOC
M22: NC[A] - 25 L/kgOC
MRID 47127830
A  "NC" means not calculated due to no absorption.

   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 exposure.  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 Leaching 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 Models 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 Model (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 by the FIFRA SAP (USEPA, 2005; 2005a).  The conceptual model (Figure 1) represents 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 drives 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.

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 significantly affect pesticide transport including precipitation, evaporation, snow, temperature, and wind.  Crop descriptions are needed only 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 (Sharpen(TM) formulation).

Table 5.  FIRST input parameters for total residues of saflufenacil following use on tree plantations and non-agricultural areas.  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.
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/kgOC)
5.9
Represents the mean of the lowest KOC values for the residues of concern in non-sand soils (n=7).
MRID 47127829
MRID 47127830
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 analysis 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 identified residues of concern (i.e., saflufenacil, M01, M02, M07, M08, M15, and M22).

	Standard percent cropped areas (PCA) are used as conservative default estimates of the extent of watershed on which agricultural crops of unknown specific PCA are grown (Effland 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 coefficients (KOC = 5.9 L/kgOC) 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.  

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/kgOC)
5.9
Represents the mean of the lowest reported KOC values.
MRID 47127829
MRID 47127830
Aerobic Soil Metabolism Half-life (days)
1627
Represents the median total residue half-life 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 Tables 7 and 8.  The mean of the lowest reported organic carbon partition coefficients (KOC = 5.87 L/kgOC) 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.  The modeled scenario represents an acidic soil where saflufenacil will not hydrolyze; therefore, an arbitrarily high hydrolysis half-life (10,000 days) was selected to approximate stability to hydrolysis.

Table 7.  PRZM GW input parameters for total residue degradation rates 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)
1627
Represents the median total residue half-life in four soils.
MRID 47445901
Organic Carbon Partition Coefficient (KOC) (L/kgOC)
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 modified 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 residues might be highly mobile and relatively 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 organic 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 (Delmarva 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

      1.1.1.       Modeling Results

	Screening estimates generated for drinking water exposure assessment are listed in Table 9.  The proposed use pattern for the Sharpen(TM) 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.  Modeled estimates are 1-in-10-year peak and 1-in-10-year annual mean values.  The 30-year daily 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 II.  

Table 9.  Drinking Water Exposure Estimates for the Proposed Maximum Use Patterns 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 90-day running average.

	Exposure estimates for total residues in surface water include a 1-in-10-year peak of 37.3 ug/L and a 1-in-10-year annual average of 23.8 ug/L.  The Tier I screening EDWC for total residues in ground water was 1.1 mg/L (ppm).  This value is 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 EDWCs in ground water for use in dietary risk assessment are 180 ug/L for acute exposure and 173 ug/L for chronic exposure.  Figure 2 displays EDWCs in ground water simulated with PRZM GW over 30 years.

Figure 2.  Exposure estimates of saflufenacil in Delmarva ground water over thirty years, generated with PRZM GW and a provisional non-agricultural scenario.

      2.1.2.       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 considered in this assessment.

1. CONCLUSIONS

	Screening drinking water exposure estimates for proposed saflufenacil uses 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 ug/L) may be higher than those in surface water (24-37 ug/L).

2. 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 Reassessment.  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 Framework 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 Pesticides.  U.S. Environmental Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division.  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 Protection 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 Assessment: 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 Protection Agency, Office of Pesticide Programs, Environmental Fate and Effects Division.  Mar. 26, 2008.

USEPA.  2009.  Ingredient: Saflufenacil.  Report of the Residues of Concern Knowledgebase Subcommittee (ROCKS).  U.S. Environmental Protection Agency, Office of Prevention, Pesticides, and Toxic Substances, Health Effects Division.  Internal memorandum.  Jan. 6, 2009.

USEPA.  2009a.  Water Models.  U.S. Environmental Protection Agency, Pesticides: Science and Policy, Models and Databases.  Last updated Mar. 23, 2009.  Online at: http://www.epa.gov/oppefed1/models/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

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(R)), Hazardous Substances Data Bank (HSDB(R)).  Last updated: Jun. 12, 2008.  Online at: http://toxnet.nlm.nih.gov/

   2.1.    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.: 132458.  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 Triangle 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, North 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 Corporation, 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 14C-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 14C-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, North Carolina.  BASF No.: 133487.  Jan. 4, 2008.

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 Research, 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., Northwood, 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 field 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.

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
Saflufenacil
BAS 800H
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: C17H17ClF4N4O5S
MW: 500.86 g/mol
                                       
                                       

                    MAJOR (>10%) TRANSFORMATION PRODUCTS
M01
M800H01

N'-[2-Chloro-4-fluoro-5-(3-methyl-2,6-dioxo-4-(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)benzoyl]-N'-isopropylsulfamide 

Formula: C16H15ClF4N4O5S
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)
M02
M800H02
N'-[2-Chloro-5-(2,6-dioxo-4-(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)-4-fluorobenzoyl]-N-isopropyl-N-methylsulfamide 

Formula: C16H15ClF4N4O5S
MW: 486.83 g/mol
                                       
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)
M04
M800H04
Formula: C17H19ClF4N4O6S
MW: 518.87 g/mol
                                       
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
M07
M800H07

N-{4-Chloro-2-fluoro-5-[({[isopropyl (methyl) amino] sulfonyl} amino) carbonyl] phenyl}-N'-methylurea

Formula: C13H18ClFN4O4S
MW: 380.83 g/mol
                                       
                                       
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)
M08
M800H08

N'-[2-Chloro-4-fluoro-5-(3-methyl-2,6-dioxo-4-(trifluoromethyl) tetrahydro-1(2H)-pyrimidinyl) benzoyl]-N-isopropyl-N-methylsulfamide

Formula: C17H19ClF4N4O5S
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)

M15
M800H15
N-{4-Chloro-2-fluoro-5-[({[isopropyl (methyl) amino] sulfonyl} amino) carbonyl] phenyl}-4-4-4-trifluoro-3,3-dihydroxybutanamide 

Formula: C15H18ClF4N3O6S
MW: 479.84 g/mol
                                       
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)
                                  nd[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]sulfonyl}amino)carbonyl]anilino}carbonyl)(methyl)amino]-4,4,4-trifluorobutanoic acid 

Formula: C17H21ClF4N4O6S
MW: 520.89 g/mol
                                       
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: C3H4F3NO
MW: 127.07 g/mol
                                       
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

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

Formula: C2HF3O2
MW: 114.02 g/mol
                                       
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: C6H8F3NO4
MW: 215.13 g/mol
                                       
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: C3H3F3O
MW: 112.05 g/mol
                                       
Aerobic soil
                                not identified

                                       
Anaerobic soil
                                not identified

                                       
Soil photolysis
                                not identified

                                       
Aq. photolysis -pH5
Aq. photolysis -pH7
                                   3.2 (20)
                                    20 (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
TFP
1,1,1-Trifluoro-2-propanol

CAS-no: 374-01-6

Formula: C3H5F3O
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: C17H15ClF4N4O6S
MW: 516.86 g/mol
                                       
                                       
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 aqueous 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.
 
 
 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: C16H17ClF4N4O5S
MW: 488.85 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
M11
M800H11
N'-[2-Chloro-5-(2,6-dioxo-4-
(trifluoromethyl)-3,6-dihydro-1(2H)-pyrimidinyl)-4-fluorobenzoyl]-N-isopropylsulfamide

Formula: C15H13ClF4N4O5S
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: C15H18ClF4N3O6S
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: C12H16ClFN4O4S
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
M24
M800H24

(2E)-3-({[4-Chloro-2-fluoro-5-({[(methylamino)sulfonyl] amino}carbonyl)aniline]carbonyl}amino)-4,4,4-trifluoro-2-butenoic acid 

Formula: C13H11ClF4N4O6S
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: C13H8ClF4N3O3
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: C15H15ClF4N4O5S
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: C14H13ClF4N4O5S
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
M30
M800H30

2-Chloro-4-fluoro-5-(3-methyl-2,6-dioxo-4-(trifluoromethyl)tetrahydro-1(2H)-pyrimidinyl)benzamide 

Formula: C13H10ClF4N3O3
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: C11H14ClFN4O4S
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: C12H6ClF4N3O3
MW: 351.65
                                       
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: C17H19ClF2N4O6S
MW: 480.88 g/mol
                                       
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

Appendix II.  Model Input/Output Data.

Table II.1.  Summary of Input/Output Files.
                                   File name
                                     Date
                              Location/Simulation
                                       
                          Input/Output File 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 PRZM 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
                                  W93721.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  HYDROLYSIS   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

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
 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
 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