### Test Material: S ulfentrazone



### MRID 48958901



### Title: Keenan, D .J. and A. DePompe i

. 2012. Anaerobic soi l metabolism of 

# e

4 

### CJSulfentrazone



### EPA PC Code: 129081



### OCSPP Guideline: 835.4200



### For Cambridge Environmental:

Primary Reviewer: Dana Worcester 

### Signature:

# Q~**w~ ·** 

Date: 111 1 2/13



### Secondary Rev i ewer: Kath l een Ferguson Signature:

# 'l(~t?frenv

Date: 1 1 / 12 / 1 3



### QC/QA Manager: Joan Gaidos



### For the Environmental Protection Agency:

Final Reviewer: Michael Barrett 

### Signature: 

# /--d'/{

Date: 11/12/13



### Date: 9 / 12 / 2014Sulfentrazone (PC 129081 ) MRID 48958901

Page 2 of 19 

### A na erobic Degradation of Sulfentrazone in Soil

Report: MRID 48958901

. Keenan, D.J. and A. DePompei. 2012. Anaerobic soil

metabolism of [ 14 

### C]Sulfentrazone

. Unpublished study performed by Ricerca

Bio sciences, LLC, Concord, Ohio and sponsored and submitted by FMC Corporation, Ewing, New Jersey . Ricerca Study No.: 027634

. FMC Study No.:

162E2511E1

. FMC Report No.: PC

- 0775. Experiment started September 22, 2011 and terminated April 15, 2012 (p

. 15). Fina l report issued September 18,

2012.

Document No.: MRID 4 8958901

Guideline: OCSPP 835.4 2 00

Statements: The study was conducted according to USEPA Principles of Good Laboratory

Practice (p. 3 )

. Signed and dated Data Confidentiality

, GLP

, and Quality

Assur ance s tatements were provided (pp. 2

- 4 )

. The authenticity of the study report is certified in the Quality Assurance Statement.

Classification: This study is classified as supplemental

. Redox potentials were provided only as a

range, and pH and dissolved o xygen levels throughout the study were not reported

. The water used to flood the soil was not characterized. The pesticide use history for the soil was not reported , and it was not demonstrated that the water and soil were pesticide

- free prior to use. Limi ts of Detection and Quantification were not reported.

PC Code: 1290 81

Reviewer: Michael Barrett

U.S. EPA Date: September 12 , 2014

E xecutive S ummary

The anaerobic transformation of [ phenyl

- U

14 

### C]

- and [carbonyl

14 

### C]

- labeled sulfe ntrazone was studied in a sandy loam soil (pH 6.8, CEC 10.4 meq/100 g, 0.89% O.M.) from California (exact source or soil classification were not specified) for 120 days in a closed system in the dark at 2 0  C following 30 days of aerobic incubation. The soi l was treated at 1. 71

- 1.73 mg a.i./kg, equivalent to

a field rate of 0.42 kg a.i./ ha . Anaerobic conditions were established by flooding with water (uncharacterized) plus a nitrogen gas atmosphere

. T he test systems were connected to individual

continuous fl ow

- through volatile trapping system

. The so il was viable at study termination.

In soil treated with the phenyl label, o verall mass balance range d from 96.6

- 108.1 % of the applied

. In soil treated with the carbonyl label, overall mass balance rang ed from 9 4 .8

- 101.8% of the applied.

O bserved DT 50 

### values, calculated half

- lives, and information on transformation products are listed

in Table 1

.

In soil treated with the phenyl label, extractable radioactivity decreased from 9 9.1 % of the applied at day 0 to 93

. 3 % at 30 days posttreatment (pre

- flooding) and was 44.7 % at 120 days postflooding

. Unextracte d radioactivity increased from 0 .3% of the applied at day 0 to 6.1 % at 30 days
posttreatment , was a maximum 9.4% at 14 days postflooding and was 9. 0 % at 1 20 daysSulfentrazone (PC 129081 ) MRID 48958901

Page 3 of 19 

### p ostflooding

. Total 14 

### CO 2 

### increased to 0.5 % of the applied at 1 2 0 days postflooding ; volatile organics were 0.1%.

In soil treated with the carbonyl label, extractable radioactivity decreased from 98.1% of the applied at day 0 to 92.4% at 30 days posttreatm ent (pre

- flooding) and was 41.1% at 120 days postflooding

. Unextracted radioactivity increased from 0.3% of the applied at day 0 to 7.7% at 30 days
posttreatment , was a maximum 9.2% at 14 days postflooding and was 8.2% at 120 days postflooding

. Total 14 

### CO 2 

### was 0.1

- 0.3% of the applied at 90

- 120 days post flooding ; volatile organics were 0.1%.

Table 1. Results S ynopsis: A na erobic Soil Metabolism of S ulfentrazone

Total System Observed

DT 50 (days) Calculated

Half

- life (days) 1 Model

Parameters

and Statistics 1 Tr ansformation Products Common Name

( maximum % of a pplied observed, associated interval )

Major Minor

California
Sandy l oam (2 0 °C, pH 6.8)

flooded with water (uncharacterized) >1 20 Stabl e

--- None HMS (3.3% at 120 days postflooding )

DMS ( 1.7% at 9 0 days post

- flood ing )

SCA ( 3. 7 % at 3 0 days post

- flood ing )

CO 2 (0.5% at 60

- 120 days post

- flood ing )

1 Calculated half

- lives and model parameters are in accordance with the NAFTA kinetics guidance (USEPA, 201 2 ).



### I. Materials and Methods

A. Materials

1. T est Material: [ P henyl

- U

14 

### C]

- and [carbonyl

14 

### C]

- labeled s ulfentrazone ( pp. 16

- 17, Appendix 5

, p p. 140

- 141 )

. Phenyl Specific activity: 22.9 mCi/m M ol (p. 17) Radiochemical purity: 98.3% Chemical purity: Not reported

Lot No.: 54175

- 2

- 22

Ca rbonyl Specific activity: 30.6 mCi/m M ol (p. 17). Radiochemical purity: 99.5% Chemical purity: Not reported.

Lot No.: 54175

- 1

- 22

Solubility in water: Not reportedSulfentrazone (PC 129081 ) MRID 48958901

Page 4 of 19 

### 2. Reference Compounds: The following standards were used in the analysis

.

Table 2. Reference Compounds
Applicant’s Code Name (synonyms) Chemical Name Purity (%) Lot No.

Sulfentrazone N

- [2, 4

- D i chloro

- 5

- [4

- difluoromethyl

- 4,5

- dihydro

- 3

- me thyl

- 5

- oxo

1H

- 1,2,4

- triazol

- 1

- yl]phenyl]methanesulfonamide -- E9337:19

Sulfentrazone

- 3

-

car boxylic acid (SCA) 1

- [2,4

- D ichloro

- 5

- [N(methylsulfonyl)amino

- phenyl]

- 4

- difluoromethyl

- 4,5

- dihydro

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 3

- carboxylic

acid -- SU

- 4

3

- Desmethyl sulfentrazone (DMS) 1

- [2,4

- D ichloro

- 5

- (N

- (methylsulfonyl)amino

- phenyl]

- 4

- difluoromethyl

- 1H

- 1,2,4

- triazol

- 5(4H)

- one -- SU

- 24

3

- Hydroxymethyl

sulfentrazone (HMS) 1

- [2,4

- D ichloro

- 5

- (N

- (methylsulfonyl)amino

- phenyl]

- 4

- difluoromethyl

- 3

- hydroxy

- methyl

- 1H

- 1,2,4

- triazol

- 5(4H)

- one -- SU

- 29

Methyl triazole 4

- D ifluoromethyl

- 5

- methyl2,4

- dihydro[1,2,4]

- triazole

- 3

- one

-- SU

- 32 Data obtained from p p. 18

- 20 and Appendix 1, pp. 111

- 115 of the study report.

-- = Not reported.



### 3. S oil : Soil collection and characterization are summarized in Table 3 and Table 4

, respectively.

Table 3. Descriptio n of Soil Collection and Storage

Description Details

Geographic location California

Soil series Not reported

Pesticide use history at the collection site Not reported

Collection date July 26, 2011

Collection procedures Collected in accordance with ISO 10381

- 6

Sampling depth Not reported

Storage temperature 4 ± 2°C

Storage length Not reported.

Soil p reparation Wet siev ed (2 mm)

. Data obtained from p . 20 of the study report.



### Table 4. P roperties of the Soil
Property: Details

Soil Texture (USDA): Sandy loam

% Sand 66

% Silt 20
% Clay 14
pH [1:1 soil:water] 6.8
Organic carbon (%) 1 0.52
Organic matter (%) [met hod not reported] 0.89
Cation Exchange Capacity (meq/100 g) (method not reported) 10.4

CaCO 3 equivalence (%) Not reported
Soil Moisture Content (%):

At 1/3 bar 12.0

At 15 bar 5.8
Bulk density (g/cm 3 , disturbed) 1.32Sulfentrazone (PC 129081 ) MRID 48958901

Page 5 of 19 

### Property: Details

Microbial Bioma ss (μg/g):

At initiation Not tested

At termination 48.7
Soil taxonomic classification (USDA or other)

-- Data obtained from p. 28; Table 1 , p. 35 ; and Appendix 3, pp. 129

- 130 of t he study report. Soil texture confirmed by

reviewer usi ng USDA

- NRCS technical support tools

. 1 Determined by reviewer: organic carbon (%) = organic matter (%)/1.72.



### B. S tudy Design

1. Experimental Conditions: Ta ble 5 summarizes the experimental conditions.

Table 5. Experimental Design

Experimental Design Details

Duration of the test 150 days; 30 days of aerobic incubation followed by 120 days of

anaerobic incubation

Soil condition: (Air dried/fresh) The soil was stored at 4 ± 2  ̊C and equilibrated to study

conditions for 4 weeks prior to treatment Soil (g/replicate) ca . 5 0 g (dry wt.)
Application rates:

Nominal 1 .68 mg a.i./kg ( equivalent to 0.42 kg a.i./ ha )

Actual Phenyl: 1.71 mg a.i. /kg Carbonyl: 1.73 mg a.i./kg
Control conditions (if used) No sterile controls were u sed.
Number of Replicates:
Controls ( if used) No sterile controls were used.

Treatment Duplicate samples from each label treatment were collected at each sampling interval.
Test Apparatus:

Type/material/volume Glass wide mouth bottle s ( ca . 125 mL ) containing treated soil or

water:soil were c onnected to individual flow

- through volatile trapping system and incubated in a temperature controlled room

.
Details of traps for CO 2 and organic volatiles ( if any) Humidified air or nitrogen gas (postflooding) were passed continually through the samples and then through one bottle of ethylene glycol and two bottles of 1N NaOH.
If no traps were used, is the system closed/open? Traps were used

.
Identity and concentration of co

- solve nt None, the test substance was dissolved in water

Test Material:

Volume of the test solution

used/treatment 1 mL

Application method Glass pipette

Is the co

- solvent evaporated? Not applicable
Any indication of the test material a dsorbing to the walls of the test apparatus? Not reported.

Experimental Conditions:

Temperature (  C) 2 0 ± 2 oC

Continuous darkness YesSulfentrazone (PC 129081 ) MRID 48958901

Page 6 of 19 Experimental Design Details

Moisture content Aerobic phase : prior to treatment, the soil moisture was adjusted

to 5 0 % MWHC

. Anaerobic phase : treated soil flooded with ca. 35 g o f water (1

- 3 cm water layer) after 30 days of aerobic incubation.

Moisture maintenance method During aerobic incubation , samples were periodically monitored

. Other details (if any) None.

Data o btained from pp. 20

- 2 3 , 28; Table 2 , p. 36 of the study report.



### 2. Sampling during Study Period : Table 6 summarizes sampling during the study period.

Table 6. Sampling during Study Period

Criteria Details

Sampling intervals A erobic phase: 0, 30 days posttreatment Anaerobic phase: 14, 30, 60, 90, 120 postflooding

Sampling method D up licate samples from each label treatment were collected at each

interval.

Method of collection of CO 2 and organic volatile compounds NaOH and ethylene glycol trapping solution s of each respective

b ottle w ere collected at each sampling interval.

Sampling Intervals/Times

Sterility check Sterile controls were not used.

Moisture conte nt P eriodically monitored

.

Redox potential, other Measured during anaerobic incubation

. pH and dissolved oxygen

were not measured.

Sample storage before analysis Water and soil were generally analyzed immediately

. Soil, extracts and trapping solutions we re stored at <5 ̊C when not in use

. Other observations (if any) None.

Data obtained from p. 23 , 25 of the study report.



### 3. Analytical Procedures:

Separation of the water and soil: T he w at er layer, when present, was removed by decanting (p.

25 ).

Extraction M ethods: Water was analyzed directly using LSC and HPLC.

Soil was extracted on ce with acetonitrile and twice with aceton itrile:water (80:20 , v:v ) by shaking at
room temperature (p. 2 5 ). Resulting extracts were analyzed for total radioactivity by LSC. The

acetonitrile extr act was concentrated under a stream of nitrogen and analyzed by HPLC ; the acetonitrile:water extract was apparently not further analyzed.

Determination of U nextracted R esidues: Extracted soil was analyzed for total radioactivity b y LSC following combustion (p. 26 ). Une xtracted residues in soil were < 10% of the applied and additional analysis was not conducted

.

Determination of V olatile Residues : Aliquots of the trapping solutions were analyzed by LSC. The presence of CO 2 

### was not confirmed.Sulfentrazone (PC 129081 ) MRID 48958901

Page 7 of 19 

### Total R adioactivity M easurement: Total 14 

### C residues were determined by summing the concentrations of residues measured in the water layers (when present), soil extracts, extracted so il and volatile trapping solutions (p. 28, Tables 3

- 4, p. 37 ).

Derivatization M ethod A derivatization method was not employed.

Identification and Q uantification of P arent C ompound and Transformation Products : Water

and s oil extracts were analyzed by HPLC using a Luna C 18 column eluted with a gradient mobile phase of (A) 0.01M ammonium acetate in water (days 0, 14, 30) or HPLC water (days 60, 90, 120) and (B) acetonitrile (p. 2 4 ). A second confirmatory method was not utilized.

Detection Li mits (LOD, LOQ) for the P arent Compound and T ransformation P roducts : Limits of detection (LOD) and quantitation (LOQ) were not reported

.

II. R esults and Discussion

A. Data :

Study results, including total mass balances and distribution of radio activity, are presented in Table

7 a ( [phenyl

14 

### C]sulfentrazone applied) and 7b ( [ carbon yl

14 

### C]sulfentrazone applied)

. In the water layer, the redox potential was + 105 to + 126 mV and i n the soil, the redox potential was +37 to +69

mV (p. 28)

. The temperatur e was maintained at 2 0 ± 2  C (Appendix 4, p. 136)

.

B. Mass Balance:

In soil treated with the phenyl label, overall mass balance range was 96.6

- 108.1% of the applied (Table 3, p. 37). In soil treated with the carbonyl label, overall mass balance range was 94.8

- 101.8% of the applied (Table 4, p. 37). Recoveries were within guideline requirements.

C. Bound and Extractable Residues:

In soil treated with the phenyl label, extractable radioactivity decreased from 99.1% of the applied at day 0 to 93.3 % at 30 d ays, then post

- flooding was 44.7% at 120 days (Table 3, p. 37). Unextracted radioactivity increased from 0.3% of the applied at day 0 to 6.1% at 30 days, then post

flooding was 6.9

- 9.4% at 14

- 120 days.

In soil treated with the carbonyl label, extractable radioactivity decreased from 98.1% of the applied at day 0 to 92.4% at 30 days, then post

- flooding was 41.1% at 120 days (Table 4, p. 37). Unextracted radioactivity increased from 0.3% of the applied at day 0 to 7.7% at 30 days, then post

flooding was 4.9

- 9.2% at 14

- 120 days.

D. Volatilization:

Volatile 14 

### CO 2 

### (identification not confirmed) was ≤0 .5% of the applied for both labels (Tables 3

- 4, p. 37). Volatile organics were ≤0.1%

.Sulfentrazone (PC 129081 ) MRID 48958901

Page 8 of 19 

### Table 7 a

. Transformation of [phenyl

14 

### C]sulfentrazone, expressed as a perce ntage of the applied radioactivity

, in flooded anaerobic sandy loam soil following 30 days of aerobic incubation

. Sampling Interval (days) Aerobic Anaerobic ( postflooding (posttreatment) )

0 30 1 14 (44) 30 (60) 60 (90) 90 (120) 120 (150)

Replicate 1 2 1 2 1 2 1 2 1 2 1 2 1 2.0

Sulfentrazone 99.1 96.3 83.3 86.1 88.1 86.4 86.4 89.3 88.3 86.0 83.0 84.8 92.6 96.9

SCA 0.0 0.0 2.4 3.2 2.6 2.1 2.6 3.2 3.3 3.3 2.5 2.8 0.8 1.1

HMS 0.0 0.0 2.7 0.0 0.0 0.0 0.0 0.0 0.3 0.6 1.1 1.1 0.0 0.0

DMS 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 0.0 0.0 0.0

Extractables 99.1 96.3 93.3 95.4 70.3 41.7 42.3 42.2 44.6 46.3 42.4 43.8 44.7 44.5

Water na na na na 20.5 46.8 46.7 50.3 48.0 47.9 49.6 48.8 50.5 54.0

Unextracted residues 0.3 0.2 6.1 4.9 8.7 9.4 8.7 7.0 9.2 8.8 7.6 8.5 6.9 9.0

CO 2 na na 0.3 0.3 0.2 0.2 0.1 0.1 0.5 0.5 0.5 0.5 0.5 0.5

Volatile organics na na 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1

Mass balance 99.4 96.6 99.8 100.6 99.7 98.1 97.7 99.6 102.4 103.5 100.0 101.6 102.7 108.1

Data obtained fr om Table 3, p. 37 and Table 15, p. 43 of the study report. 1 Prior to flooding. 1 na = not applicableSulfentrazone (PC 129081 ) MRID 48958901

Page 9 of 19 

### Table 7b. Transformation of [carbonyl

14 

### C]sulfentrazone, expressed as a percentage of the applied radioactivity

, in flooded anaerobic sandy loam soil f ollowing 30 days of aerobic incubation

. Sampling Interval (days) Aerobic Anaerobic (postflooding (posttreatment))

0 30 1 14 (44) 30 (60) 60 (90) 90 (120) 120 (150)

Replicate 1 2 1 2 1 2 1 2 1 2 1 2 1 2

Sulfentrazone 98.1 95.2 88.1 89.2 83.3 90.3 89.3 8 8.6 84.5 89.2 85.8 86.8 84.9 85.8

SCA 0.0 0.0 1.5 1.2 2.1 1.7 2.4 3.7 2.7 2.1 1.3 1.6 1.5 0.3

HMS 0.0 0.0 1.4 1.9 0.0 0.0 1.3 0.6 1.0 1.2 1.2 1.1 3.3 1.7

DMS 2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.0 0.0 0.2 0.0 0.0

Extractables 98.1 95.2 91.1 92.4 65.2 45.2 53.2 54.9 47.1 46.2 49.3 53.5 41.1 40.2

Water na na na na 20.2 46.8 39.7 38.0 47.3 47.2 39.6 36.8 49.2 48.0

Unextracted residues 0.2 0.3 7.7 7.7 9.2 8.3 4.9 6.2 5.6 8.2 6.7 8.7 8.2 7.8

CO 2 na na 0.1 0.1 0.2 0.2 0.2 0.2 0.2 0.2 0.3 0.3 0.1 0.1

Volatile organics na na 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 0.0 0.0 0.0 0.0

Mass balance 98.3 95.5 98.7 100.2 94.8 100.5 98.1 99.3 100.2 101.8 95.9 99.4 98.5 96.0
Data obtained from Table 4, p. 37 and Table 17, p. 44 of the study report. The study author st ated that m ethyl triazole was not detected at any time during the study (“0%”: pp. 14, 33; Table 17, p. 44). 1 Prior to flooding.

2 DMS was detected only in the water layer (Table 9, p. 40 and Table 13, p. 42).

n a = not applicableSulfentrazone (PC 129081 ) MRID 48958901

Page 10 of 19 

### E . Transformation of Parent Compound: Transformation kinetics of the parent compound (combined labels) in the total systems are summarized in Figure 1

. Since the concentrations of

sulfentrazone for the phenyl tre atment at 120 days appear ed to be skewed by the high recoveries and since inclusion of these samples resulted in a negative value , the half

- life was determined without these samples. Sulfentrazone was nearly stable, with a n estimated half

- life approaching 10

years (very little transformation occurred over the 100 days of anaerobic incubation)

. Transformation product information summarized in Table 8

.

The study author s determined that the 120 day data were outliers and therefore, determined a half

life bot h including and excluding the day 120 values (p. 33). Using first

- order linear regression analysis, the study authors determined a half

- life 4

, 149 days for the phenyl label and 956 days for the carbonyl label with the 120

- day data included. The half

- life o f the phenyl label without the 120 day data was 665 days.

Figure 1 . Kinetic model fitting for sulfentrazone in anaerobic sandy loam soil.

T able 8 . Transformation Products of Sulfentrazone in Anaerobic Sandy Loam Soil

System Transformation product(s) Maximum

% AR

Observed Associated

Interval (days) Final % AR

Observed Final Interval

(days)

California Sandy loam (20°C, pH 6.8) flooded

with water HMS 3.3 120 3.3

120 DMS 1.7 90 0.0

SCA (3

- Carboxylic) 3.7 30 1.5

Data obta ined from Table 15 , p. 43 and Table 17, p. 44 of the study report

.



### Degradation Pathway for Sulfentrazone in Soil A transformation pathway was not provided by the study authors.Sulfentrazone (PC 129081 ) MRID 48958901

Page 11 of 19 

### III. . Study Deficiencies

, Reviewer's Comments , and Data Needs

1. The study author reported that redox potentials were measured in the soil and water at each sampling interval, but provided only ranges with no associated time intervals for minimum and maximum (p. 28). Detailed data should have been provided for each sampling inter val. The pH

of the water and soil throughout the study, and the dissolved oxygen levels in water were not reported.

2. The source of the water was not reported , and it was not characterized.

3. Pesticide use history at the site from which the soil was obtaine d was not provided. The soil is typical of an agricultural soil, but the land usage was not reported. It was not confirmed that the soils were free of pesticide residues.

4. Limits of Detection (LOD) and Quantitation (LOQ) for sulfentrazone and its transfor mation products were not reported.

5. The details of the soil collection were not reported. The only information provided identifying

the source of the soil was that it was from California

.

6. In the soil treated with the phenyl label, the final sampling inte rval showed a concentration (92.6

- 96.9%) higher than the anaerobic time 0 concentration (83.3

- 86.1% ; Table 15, p. 43 ). Since inclusion of these samples resulted in a negative half

- life ( see below), the half

- life reported in this study was generated without data from this set of samples.

7. The study was conducted using one soil. Under current OCSPP guidelines, rates of

transformation should be determined in at least four soils.Sulfentrazone (PC 129081 ) MRID 48958901

Page 12 of 19 

### 8. The viability of the soil was not determined prior to study initiation. The soil was tested at termination (p. 28)

. It was therefore not possible to determine if the activity of the soil

microflora decreased as a result of treatment or over time.

9. The analytical methods suggest that the acetonitrile:water extracts of the soil were analyzed only using LSC (p. 25). The concentration of residues in this fraction was not reported, so it is unknown if failure to analyze these residues by HPLC had any impact on the reported

concentrations of identified residues.

The following are requi red to potentially upgrade this study from “supplemental” to “acceptable”

status:

1. Detailed redox data are needed for each sampling interval. Please provide the pH of the water and soil throughout the study, and the dissolved oxygen levels in water.

2. The s ource of the water used to flood the soil needs to be reported and characterized.

3. Pesticide use and land use history at the site from which the soil was obtained should be provided.. Confirmation must be provided that the soils were free of pesticide res idues that might alter soil bioactivity and also that no residues related to sulfentrazone were present prior to the initiation of the study.

4. The exact collection location and the taxonomic classification of the test soil should be provided. In the regist rant’s report, the only information provided identifying the source of the soil was that it was

from California.

5. Limits of Detection (LOD) and Quantitation (LOQ) for sulfentrazone and each of its transformation products for all soil and water samples shou ld be reported (on page 28 of the registrant’s report there is an implication that soil detection limits were at or below 1% of the 1.68 ug/g application amount, generally a better sensitivity than this is desired in laboratory metabolism studies).

6. Can th e registrant provide any further information on why the residues of parent sulfentrazone

increased at the final sampling interval back to approximately the levels observed at the time of application (30 days before flooding)? From the available data it app ears that complete stability of

sulfentrazone in anaerobic soils needs to be assumed.

7. The viability of the soil was not determined prior to study initiation. Further information is needed to determine if the activity of the soil microflora was normal at t he time of application and on whether bioactivity decreased over the course of the experiment.



### IV. R eferences

1. U.S. Environmental Protection Agency. 1982. Pesticide Assessment Guidelines, Subdivision N, Chemistry: Environmental Fat e, Section 162

- 2, Anaerobic Soil Metabolism Studies

. Office of Pesticide and Toxic Substances, Washington, DC

. EPA 540/9

- 82

- 021.Sulfentrazone (PC 129081 ) MRID 48958901

Page 13 of 19 

### 2. U.S. Environmental Protection Agency. 2008. Fate, Transport and Transformation Test

- Guidelines, OPPTS 835.4 2 00, A na erobic Soi l Metabolism. Office of Prevention, Pesticides and Toxic Substances, Washington, DC. EPA 712

- C

- 08

- 01 7

.Sulfentrazone (PC 129081 ) MRID 48958901

Page 14 of 19 DER ATTACHMENT 1

. Sulfentrazone and Its Environmental Transformation Products. A

Code Name/ Synonym Chemical Name Chemical Structure Study Type MRID M aximum %AR (day) Final %AR

(study length)

PARENT

Sulfentrazone IUPAC: 2′,4′

- Dichloro

- 5′

- (4

- difluoromethyl

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1 H

- 1,2,4

- triazol

1

- yl)methanesulfonanilide

CAS: N

- [2,4

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1 H

- 1,2,4

- triazol

1

- yl]phenyl]methanesulfonamide

CAS No.: 122836

- 35

- 5

Formula : C 11 H 10 Cl 2 F 2 N 4 O 3 S

MW: 387.1 g/mol

SMILES: CLc1cc(CL)c(NS(=O)(=O)C)cc 1N2N=C(C)N(C(F)F)C2(=O) 835.4200

Anaerobic

soil

metabolism 48958901 Sandy

loam 99.1% (0 d) 96.9% (150 d)

MAJOR (>10%) TRANSFORMATION PR ODUCTS
No major transformation products were identified.
MINOR (<10%) TRANSFORMATION PRODUCTS

Sulfentrazone 3

- carboxylic acid (SCA;

3

- Carboxylic) IUPAC: 1

- (2,4

- Dichloro

- 5

- (N

- (methylsulfonyl)amino)

- pheny]

- 4

- difluoromethyl

- 4,5

- dihydro

- 5

-

oxo

- 1 H

- 1,2,4

- tria zol

- 3

- carboxylic acid

CAS: N

- [2,4

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 5

-

oxo

- 1 H

- 1,2,4

- triazol

- 1

- yl]phenyl]methanesulfonamido

3

- carboxylic acid

CAS No.: 134391

- 01

- 08

Formula: C 11 H 8 Cl 2 F 2 N 4 O 5 S

MW: 417.18 g/mol

SMILES: 835.4200

Anaerobic

soil

metabolism 48958901 Sandy

loam 3.7% (60 d) 1.5% (150 d)Sulfentrazone (PC 129081 ) MRID 48958901

Page 15 of 19 Code Name/ Synonym Chemical Name Chemical Structure Study Type MRID M aximum %AR (day) Final %AR

(study length)
CS(=O)(=O)Nc1cc(c(cc1Cl)Cl)n 2c( =O)n(c(n2)C(=O)O)C(F)F

3

- Hydroxymethyl

sulfentrazone (HMS) IUPAC: 1

- (2,4

- Dichloro

- 5

- (N

- (methylsulfonyl)amino)

- pheny]

- 4

- difluoromethyl

- 3

- hydroxy

methyl

- 1 H

- 1,2,4

- triazol

- 5(4H)

-

one

CAS No.: 134390

- 99

- 1

Formula: C 11 H 10 Cl 2 F 2 N 4 O 4 S

MW: 403.19 g/mol

SMILES: CS(=O)(=O)Nc1cc(c(cc1Cl)Cl)n 2c(=O)n(c(n2)CO)C(F)F 835.4200

Anaerobic

soil

metabolism 48958901 Sandy

loam 3.3% (150 d) 3.3% (150 d)

3

- Desmethyl sulfentrazone (DMS) IUPAC: 1

- (2,4

- Dichloro

- 5

- (N

- (methylsulfonyl)amino)

- pheny]

- 4

- difluoromethyl

- 1 H

- 1,2,4

- triazol

- 5(4H)

- one

CAS: N

- [2,4

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 5

-

oxo

- 1,2,4

- triazol

- 1

- yl]phenyl]methanesulfonamide

CAS No.: 1 34391

- 02

- 09

Formula: C 10 H 8 Cl 2 F 2 N 4 O 3 S

MW: 373.17 g/mol

SMILES: CS(=O)(=O)Nc1cc(c(cc1Cl)Cl)n 2c(=O)n(cn2)C(F)F 835.4200

Anaerobic

soil

metabolism 48958901 Sandy

loam 1.7% (120 d) 0.0% (150 d)

Carbon dioxide IUPAC: Carbon dioxide

Formula: CO 2 MW: 44 g/mol

SMILES: C(=O)=O 835.4200

Anaerobic

soil

metabolism 48958901 Sandy

loam 0.5% (60

- 150

d) 0.5% (150 d)

REFERENCE COMPOUNDS NOT IDENTIFIEDSulfentrazone (PC 129081 ) MRID 48958901

Page 16 of 19 Code Name/ Synonym Chemical Name Chemical Structure Study Type MRID M aximum %AR (day) Final %AR

(study length)
Methyl triazole IUPAC: 4

- Difluoromethyl

- 5

- methyl

- 2,4

- dihydro[1,2,4 ]triazole

- 3

- one

Formula: C 4 H 5 F 2 N 3 O

MW: 149.1 g/mol

SMILES: Cc1n[nH]c(=O)n1C(F)F 835.4200

Anaerobic

soil

metabolism 48958901 NA NA

A AR means “applied radioactivity”

. MW means “molecular weight”. NA means “not applicable”

.Sulfentrazone (PC 129081 ) MRID 48958901

Page 17 of 19 

### Attachment 2: Statistics Spreadsheets and GraphsSulfentrazone (PC 129081 ) MRID 48958901

Page 18 of 19 

### Attachment 3: Calculations

Calculations were performed by the reviewer using R software, and the following equations.

Single First

- Order (SFO) Model

(eq. 1)

where,

C t 

### = concentration at time t (%)

C 0 

### = initial concentration (%) e = Euler’s number (

- ) k = SFO rate constant of decline (d

- 1 

### ) t = time (d)

The SFO equation is solved with R kinetics software by adjusting C 0 

### and k to minimize the objective function (S SFO 

### ) shown in equation 9.

DT 50 

### = natural log (2)/k (eq. 2)

DT 90 

### = ln (10)/k (eq. 3)

Indeterminate Order Rate Equation (IORE) Model

(eq. 4)

where, N = order of decline rate (

- )

k IORE 

### = IORE rate constant of decline (d

- 1 

### )

This equation is solved with R kinetics s oftware by adjusting C0, kIORE, and N to minimize the objective function for IORE (SIORE) (See equation 9). Half

- lives for the IORE model are calculated using equation 5, which represents a first

- order half

- life that passes through the DT 90 

### of

the IORE mod el. (Traditional DT 50 

### and DT 90 

### values for the IORE model can be calculated using equations 6 and 7.)

(eq. 5)

DT 50 

### = (eq. 6)

DT 90 

### = (eq. 7)Sulfentrazone (PC 129081 ) MRID 48958901

Page 19 of 19 

### Double First

- Order in Parallel (DFOP) Model

(eq . 8)

where, g = the fraction of C 0 

### applied to compartment 1 (

- )

k 1 

### = rate constant for compartment 1 (d

- 1 

### )

k 2 

### = rate constant for compartment 2 (d

- 1 

### )

If C 0 

### x g is set equal to a and C 0 

### (1

- g) is set equal to c , then the equation can be solved with R

kine tics software for a , c , k 1 

### , and k 2 

### by minimizing the objective function (S DFOP 

### ) as described in equation 9.

DT 50 

### and DT 90 

### values can be calculated using equations 2 and 3, with k 1 

### or k 2 

### in place of k.

Objective Function: SFO, IORE, and DFOP are solved by minimizing the objective function (S SFO 

### , S IORE 

### , or S DFOP 

### ).

(eq. 9)

where,

S SFO 

### , S IORE 

### , or S DFOP 

### = objective function of kinetics model fit (% 2 

### ) n = number of data points (

- )

C model,t 

### = modeled value at time corresponding to C d,t 

### (%)

C d,t 

### = experimental concentration at time t (%)

Critical Value to Determine Whether SFO is an Adequate Kinetics Model

If S SFO 

### is less than S C 

### , the SFO model is adequate to describe kinetics. If not, the faster of t IORE 

### or the DFOP DT 50 

### for compartment 2 should be used.

(eq. 10)

where,

S c 

### = the critical value that defines the confidence contours (% 2 

### ) p = number of parameters (3 in this case) α = the confidence level (0.50 in this case) F(α, p, n

- p) = F distribution with α level of confidence and de grees of freedom p and n

- p