### Test Material: Chlorimuron ethyl

MRID: 49526701

Title: Aerobic Soil Metabolism of Chlorimuron Ethyl (DPX

- F6025)

EPA PC Code: 128901

OCSPP Guideline: 835.4100

For CDM Smith

Primary Reviewer: Kathleen Ferguson Signature:

Date: 3 /11/15

Secondary Reviewer: Mary Samuel Signature:

Date: 3/11/15

QC/QA Manager: Joan Gaidos Signature:

Date: 3/11/15Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 2 of 21 

### Aerobic degradation of Chlorimuron ethyl in soil

Report: MRID 49526701

. Ponte, V. 2014. Aerobic s oil Metabolism of Chlorimuron Ethyl (DPX

- F6025). Unpublished study performed by PTRL West, Hercules, California ; sponsored and submitted by E.I. du Pont de Nemours and Company, Wilmington, Delaware. Sponsor Study No.: DuPont

- 38490. PTRL West Project No.: 2 550W. Experiment started December 4 , 2013, and completed November 12 , 2014 (p. 1 2 ). Final report issued December 8 , 2014.

Document No.: MRID 49526701

Guideline: OCSPP 835.4100

Statements: The study was conducted according to USEPA GLP standards (p. 3) . Signed and dated Data Confidentiality, GLP, Quality Assurance , and Certification of Authenticity statements were provided (pp. 2

- 5 ).

Classification: This study is Supplemental

. Both soils used in the experiment were classified as clay loam. Transformat ion product MET

- 1 reached 10.2% of the applied but was not identified. In three of the four experiments, overall recoveries were <90% of the applied at one or more sampling intervals. Significant levels (15.2% of the applied) of unextracted residues were d etected in the Illinois clay loam soil, and the study author failed to use solvents with a range of dielectric constants (including a nonpolar solvent) to maximize extraction of the residues. The pesticide use history at the test sites was not reported, an d it was not confirmed that the soils were pesticide

- free prior to use.

PC Code: 128901

Reviewer: Richard Shamblen , Biologist Signature:

USEPA Date: October 30, 2015

EXECUTIVE SUMMARY

The aerobic transformation of [phenyl

- U

1 4 

### C ]

- and [pyrimidine

- 2

- 14 

### C]

- labeled chlorimuron ethyl (DPX

- F6025) was studied in a clay loam soil (pH 5.5 in CaCl 2 

### ) from Illinois and a clay loam soil (pH 5.9 in CaCl 2 

### ) from North Dakota. The experiment was conducted for up to 124 days in

darkness at 20 ° C and a soil moisture content of 50% of the maximum water holding capacity. The

soils were treated at ca. 0.2 mg a.i./kg, equivalent to a field application rate of ca. 150 g a.i./ha. Single samples (single flasks) of each treatment were collected at each sam pling interval. It was not confirmed that aerobic conditions were maintained in the soils throughout the study. The soils were viable at study initiation and at termination

.

For the Illinois clay loam soil, overall mass balances averaged 94.9 ± 6.7% of t he applied (range

89.4

- 108.0%) in the samples treated with the phenyl label and 94.0 ± 3.6% (range 87.8

- 98.7%) in the samples treated with the pyrimidine label. For the North Dakota clay loam soil, overall mass balances averaged 96.2 ± 5.0% of the applied (range 88. 5

- 104.1%) in the samples treated with the phenyl label and 95.3 ± 3.6% (range 92.5

- 103.0%) in the samples treated with the pyrimidine label.

Observed DT 50 

### values, calculated half

- lives, and information on transformation products are listed

in Ta ble 1 . Chlorimuron ethyl dissipated with an t R IORE 

### values (IORE) of 22.8 days in the Illinois clay loam soil and 105 days in the North Dakota clay loam soil. Seven transformation products were
isolated, of which six were identified.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 3 of 21 

### In the Illinois clay loam soil treated with the phenyl label, total extractable radioactivity declined from 107.3% of the applied at time 0 to 51.1% at 124 days posttreatment. Unextracted radioactivity increased to a maximum of 15.2% at 90 days and was 15.0% at 124 days. At s tudy termination, CO 2 

### totaled a maximum of 23.3%. Organic volatiles were never detected.

In the Illinois clay loam soil treated with the pyrimidine label, total extractable radioactivity declined from 98.1% of the applied at time 0 to 65.1% at 90 days pos ttreatment and was 66.6% at 124 days. Unextracted radioactivity increased to a maximum of 12.4% at 124 days. At study
termination, CO 2 

### totaled a maximum of 14.9% and organic volatiles totaled 0.2%.

In the North Dakota clay loam soil treated with the pheny l label, total extractable radioactivity declined from 101.6% of the applied at time 0 to 82.5% at 90 days posttreatment and was 91.5% at 124 days. Unextracted radioactivity increased to a maximum of 5.4% at 61 days and was 5.3% at 124 days. At study termi nation, CO 2 

### totaled a maximum of 1.1%. Organic volatiles were never

detected.

In the North Dakota clay loam soil treated with the pyrimidine label, total extractable radioactivity declined from 99.9% of the applied at time to 82.8% at 124 days posttreatme nt. Unextracted radioactivity increased to a maximum of 9.1% at 124 days. At study termination, CO 2 

### totaled a maximum of 2.5%. Organic volatiles were never detected.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 4 of 21 

### Table 1. Results Synopsis: Aerobic Soil Metabolism of Chlorimuron ethyl.

Soil Location and

Texture (Temperature, pH) Observed

DT 50 (days) Calculated

Half

- life A
(days) Model Parameters

and Statistics Transformation Products (maximum % AR, associated interval) B ,C

Major Minor

Illinois USA Clay loam soil
(20 ° C, pH 5.5) 14

- 29 t R IORE = 22 .8

IORE C 0 = 99.4

N =1.49

k = 0.00589 IN

- L8330 (39.4%, 124 days)

IN

- N6186 (20.1%, 29 days)

CO 2 (23.3%, 124 days) Unextracted residues (15.2%, 90 days) IN

- B4450 (2.6%, 7 days)

IN

- 00581 (5.3%, 7 days)

IN

- B7497 (2.0%, 61

- 90 days)

IN

- V9662 (2.7%, 29 days)

Met

- 1 (8.4%, 29 days)

North Dakota USA Clay loam soil
(20 ° C, pH 5.9) 14

- 61 t R IORE = 105

IORE C 0 = 98.4

N = 2.43

k = 7.34e

- 05 IN

- B4450 (41.3%, 124 days)

IN

- 00581 (46.3%, 29 days)

IN

- N6186 (56.9%, 124 days)

MET

- 1 (10.2%, 29 days) IN

- L8330 (6.8%, 90 days)

IN

- B 7497 (2.4%, 7 days)

CO 2 (2.5%, 124 days)

A Calculated half

- lives, model parameters, and kinetics models in accordance with the NAFTA kinetics guidance (USEPA, 2012); Indeterminate Order Rate Equation (IORE).

B AR means “applied radioactivity”

. C IN B4450, IN 00581, IN B7497, and MET

- 1 are products of the phenyl moiety only. IN N6186 and IN V9662 are products of the pyrimidine moiety only.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 5 of 21 

### I. Materials And Methods

A. Materials:

1. Test Material [ Phenyl

- U

14 

### C ]

- and [pyrimidine

- 2

- 14 

### C]

- labeled chlorimur on ethyl ( p p. 19

- 20 )

Phenyl label

Specific activity: 43.5 μ Ci/mg ; 1.61 MBq/mg (p. 20)

Radiochemical purity: 97.6%

Chemical purity: Not reported

Lot No.: CFQ41767

Pyrimidine label

Specific activity: 47.9 μ Ci/mg ; 1.77 MBq/mg (p. 20)

Ra diochemical purity: 9 9.9 %
Chemical purity: Not reported

Lot No.: CFQ41768

Solubility in water: 8.55 g/L in HPLC water (p. 20)

2. Reference Compounds: The following standards were used in the analysis ( Table 2 ).

Table 2. Reference Compounds

.

App licant’s Code Name Chemical Name Purity (%) Lot No.

Chl ori muron ethyl (DPX

- F6025)

-- 98.8 E62740

- 69

IN

- L8330

-- 99.1 E108786

- 91B

IN

- 00581

-- 99.9 03111DD

IN

- N6186

-- 99.7 E43079

- 021A

IN

- H1427

-- 95.7 AG0135

- 104

IN

- B4450

-- 99.6 004

IN

- B7497

-- 99.7 E118288

- 56

IN

- V9662

-- 99.4 E118288

- 74

IN

- D5119

- 001

-- 99.5 E100035

- 086

IN

- F8174

- 001

-- 99.5 E49662

- 15

IN

- H9235

-- 97.2 9377

- 103
Data obtained from pp. 20

- 21 and Figure 2, pp. 60

- 61, of the study report.

-- = No information.



### 3 . Soil: Soil collection and characterization are summarized in Table 3 and Table 4 , respectively.

Table 3. Description of Soil Collection and Storage

.

Description Illinois Clay loam North Dakota Clay loam

Geographic location Toulo n/Doug Murray Farm, Stark County,

Illinois Agvise Research, Grand Forks, North

Dakota

Site Description Permanent grass pasture Flat field

Soil series Tama/Toulon Not reported.

Pesticide use history at

the collection site Not report ed.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 6 of 21 Description Illinois Clay loam North Dakota Clay loam

Collection date September 19, 2013 September 16, 2013

Collection procedures Shovel

Sampling depth ≤ 20 cm

Storage conditions Refrigerated at the test facility, conditions during ca. 3 weeks between collection and receipt were not reported

. Storage length 49 days (from receipt at test facility)

Soil preparation Sieved (2 mm screen)
Data obtained from p. 22

, Table 1, p. 46, and Appendix 1, pp. 126

- 127, of the study report.



### Table 4. Properties of the Soil s.

Property Illinois Clay loam North Dakota Clay loam

Soil Texture (USDA) Clay loam Clay loam

% Sand 20 34

% Silt 46 38
% Clay 34 28

pH 1:1 in water 6.1 6.0

1:2 in 0.01M CaCl 2 5.5 5.9
Organic carbon (%) 1.62 2.73
Organic matter (%) (Walkley Black) 2.8 4.7
Cation Exchange Capacity (meq/100 g) (method not reported) 17.1 24.3

Ca Base Saturation (%) 52.4 63.4

Soil Moisture Content ( % )

1/3 Bar 30.7 31.6
Maximum Water Holding Ca pacity 47.2 51.4
Bulk density (disturbed, g/cm 3 ) 0.95 1.03

Microbial Biomass ( μ g C/g dry soil)

Initial 263 372

Final 169 195

Soil taxonomic classification F ine

- silty, mixed, superactive, mesic typic

A rgiudoll / sandy

- skeletal, mixed, mesic typic H apl ocambid Not reported

Data obtained from Table 1, p. 46, of the study report. The soil texture was confirmed and the soil taxonomic

classification determined using USDA

- NRCS technical support tools.



### B. STUDY DESIGN

1. Experimental C onditions: (Summarized in Table 5 ).

Table 5. Experimental Design

Property Details
Duration of the test (days) 124 days

Soil condition (Air dried/fresh) Fresh. Soil was acclimated to study conditions for 9 days prior to treatment

. Soil (g/replicate) 50 g (dry wt)
Application rates

Nominal 0.2 mg a.i./kg; equivalent to a field rate of ca . 1 50 g a.i./ha 1

Actual 0.19

- 0.20 mg a.i./kg

Control conditions (if used) St erile controls were not used.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 7 of 21 Property Details
Number of Replicates

Controls (if used) Sterile controls were not used.

Treatment One flask of each soil was collected at each sampling interval.

Test apparatus

Type/material/volume The test system consisted of glass bottles (250

- mL volume) containing moist treated soil ( ca. 50 g dry wt) that were attached to individual continuous flow

through volatile trapping systems and incubated in a dark temperature

controlled room . The test system is illustrat ed in Figure 3, p. 62.

Details of traps for CO 2 and other volatiles (if any) Humidified air was continually passed ( flow rate ca . 4 mL/minute ) through a sample flask, then through one bottle of ethylene glycol and two bottles of 1M aqueous KOH . The volat ile trapping system is illustrated in Figure 3, p. 62.
If no traps were used, is the system closed/open? Volatile traps were used.

Identity and concentration of co

solvent Acetonitrile, 0 .1% by volume

Test Material:

Volume of the test solution

used/treatment 50 μ L/50 g

Application method The test solution was applied uniformly to the soil surface using a glass syringe

. Is the co

- solvent evaporated? Yes
Any indication of the test material adsorbing to the walls of the test apparatus? None

Experimental conditions:

Temperature ( ° C) 20 ± 2 ° C (range not reported)

Continuous darkness Yes

Moisture content 50% of the ma ximum water holding capacity

Moisture maintenance method Samples were weighed at regular intervals and remoistened if necessary.

Other details (if any) Separate samples treated with an equal volume of pesticide

- free acetonitrile

were used for microbial biomass analysis.
Data obtained from pp. 23

- 26; Table 2, p. 47; and Figure 3, p. 62, of the study report. 1 Application rate assumes an even distribution of the test material in the top 5 cm of soil and a soil bulk density of 1.5 g/cm 3 (p. 47).



### 2. Samp ling During Study Period: (Details summarized in Table 6 ).

Table 6. Sampling During Study Period

Criteria Details

Sampling intervals (days) 0, 7, 14, 29, 61, 90, and 124 days

Sampling method Single flasks of e ach soil were collected at each sampling interval.

Method of collection of CO 2 and organic volatile compounds Volatile traps were collected at each sampling interval. KOH traps were also changed after 3 months or when analysis at any sampling interval exceeded 3,000 dpm/mL.

Sampling intervals/times for:

Sterility check (if used) Sterile controls were not used.

Moisture content Regular intervals

Redox potential, other The redox potential was not measuredChlorimuron ethyl (PC 128901 ) MRID 49526701

Page 8 of 21 Criteria Details

Sa mple storage before analysis Soils were processed immediately after sampling

. Soil extracts were initially analyzed by HPLC within ca. 1 week of extraction. Sample extracts and
extracted soils were stored in a freezer ( ca.

- 20 ° C) when not in use. Trapping solutions were stored at ambient temperatures.

Other observation (if any 

### ) None.

Data obtained from p. 26 and Table 3, p. 48, of the study report.



### 3. Analytical Procedures: (Analytical pro cedures are illustrated in Figure 4, p. 63).

Extraction Methods: The soil (entire flask) w as transferred into a flurinated plastic centrifuge bottle and soaked overnight with 0.1M ammonium acetate at ca. 5 ° C (p. 26 ; Table 3, p. 48; Figure 4, p. 63) . The next day, the soils were extracted three times with methylene chloride:methanol:acetic acid (75:25:1, v:v:v) by shaking for 1 hour/extraction at ambient

temperatures . After each extraction, the samples were centrifuged and the supernatant decanted; aliquot s of the individual extracts were analyzed using LSC. The extracts were then combined and concentrated by rotary evaporation, adjusted to ca . pH 9, and refrigerated overnight (p. 27)

. The concentrate was centrifuged and the supernatant decanted . The supern atant was further concentrated, and aliquots were analyzed using LSC, HPLC, and TLC. The precipi t ate was dissolved in methylene chloride:methanol (75:25, v:v), an d aliquots analyzed using LSC

.

Determination of Unextracted R esidues: The extracted soils we re homogenized and portions were analyzed for total remaining radioactivity using LSC following combustion ( p. 26; Figure 4, p.

63 ).

Determination of Volatile Compounds: Aliquots of the trapping solutions were analyzed by LSC (Table 3, p. 48). The identi fication of residues as CO 2 

### in the trapping solutions was confirmed by precipitation with barium chloride (p. 31).

Total radioactivity measurement: Total [ 14 

### C]residues were determined by summing the
concentrations of residues in the soil extracts, extrac ted soil, and volatile traps (Tables 4

- 7, pp. 49

- 52).

Derivatization method A derivatization method was not employed.

Identification and quantification of Parent and Transformation Compounds: Aliquots of the concentrated extracts were analyzed by HPLC u sing a LiChrospher 100 RP

- 8 column eluted with a mobile gradient phase of (A) phosphoric acid in HPLC grade water ( ca. pH 2.2) and (B) HPLC grade acetonitrile , and by HPLC using a LUNA C18 column eluted with a gradient mobile phase of (a) 20mM ammonium ace tate in HPLC grade water and (B) HPLC grade acetonitrile (p p 28

- 29 ). Samples were cochromatographed with a mixture of reference standards (p. 29).

Samples were also analyzed using one

- dimensional TLC on silica gel plates develop in

chloroform:methanol:2M ammonium carbonate aqueous (150:25:3 or 150:30:3, v:v:v; p. 29). Samples were cochromatographed with a mixture of reference standards.

Identification of radiolabeled compounds was confirmed using LS/MS (pp. 27, 29

- 31).Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 9 of 21 

### Detection Limits (LOD, LOQ) for the Parent and Transformation Products : For LSC, Limits of Detection (L O D) were 9.8 cpm for combusted soil, 9.3 cpm for the ethylene glycol solution, 4.2 cpm for the KOH solution, 11.6 cpm for the soil extract, 12.6 cpm for the aqueous supernatant (Appendix 5, p. 165). Limits of Quantification (LOQ) were 46, 39, 50, 128, and 139 cpm, respectively. For HPLC, L O D were 19.6 cpm and L O Q were 230 cpm. For LSC, LOQ were 0.89%
for the soil extracts, 0.53% for the combusted soil, and 0.18% for the trapping solution s (Appendix 5, p. 164) . For HPLC

, LOQ were 3.97% (Appendix 5, p. 165)

.

II. Results and Discussion

A. Data

Study results including total mass balances and distribution of radioactivity are presented in Tables

7a

- 7b

. No determination s were made to verify that aerobic conditions were maintained in the soils. Soils were viable at study initiation and termination (Table 1, p. 46).

B. Mass Balance

For the Illinois clay loam soil, overall mass balances averaged 94.9 ± 6.7% of the applied (range

89.4

- 108.0%) in the samples treated with the phenyl label and 94.0 ± 3.6% (range 87.8

- 98.7%) in the samples treated with the pyrimidine label ( Tables 4

- 5, pp. 49

- 50 ). For the North Dakota clay loam soil, overall mass balances averaged 96.2 ± 5.0% o f the applied (range 88. 5

- 104.1%) in the samples treated with the phenyl label and 95.3 ± 3.6% (range 92.5

- 103.0%) in the samples treated with the pyrimidine label ( Tables 6

- 7, pp. 51

- 52 ). Recoveries tended to be lower at later sampling

intervals but there was no clear downward trend since recoveries at the final sampling interval were

similar to those at 14

- 29 days posttreatment.

C. Unextracted and Extractable Residues

In the Illinois clay loam soil treated with the phenyl label, total extractable radio activity declined from 107.3% of the applied at time 0 to 51.1% at 124 days posttreatment (Table 4, p. 49). Unextracted radioactivity increased to a maximum of 15.2% at 90 days and was 15.0% at 124 days. In the same soil treated with the pyrimidine label, total extractable radioactivity declined from 98.1% of the applied at time 0 to 65.1% at 90 days and was 66.6% at 124 days (Table 5, p. 50). Unextracted radioactivity increased to a maximum of 12.4% at 124 days.

In the North Dakota clay loam soil treated with the phenyl label, total extractable radioactivity declined from 101.6% of the applied at time 0 to 82.5% at 90 days posttreatment and was 91.5% at 124 days (Table 6, p. 51). Unextracted radioactivity increased to a maximum of 5.4% at 61 days and

was 5 .3% at 124 days. In the same soil treated with the pyrimidine label, total extractable radioactivity declined from 99.9% of the applied at time to 82.8% at 124 days (Table 7, p. 52). Unextracted radioactivity increased to a maximum of 9.1% at 124 days.

D. Volatilization

At study termination, CO 2 

### totaled maximums of 23.3% and 14.9% in the Illinois clay loam soils treated with the phenyl and pyrimidine labels, respectively ( Tables 4

- 5, pp. 49

- 50) . CO 2 

### totaled

maximums of 1.1% and 2.5% in the North Dakota cl ay loam soils treated with the phenyl andChlorimuron ethyl (PC 128901 ) MRID 49526701

Page 10 of 21 

### pyrimidine labels, respectively ( Tables 6

- 7, pp. 51

- 52) . Organic volatiles were detected only once in the experiments, at 0.2% of the applied in the Illinois clay loam soil treated with the pyrimidine

label at 124 days (Table 5, p. 50)

.

Table 7a. Transformation of [phenyl

- U

14 

### C]chlorimuron ethyl, expressed as a percentage of the applied radioactivity, in an aerobic Illinois clay loam soil. Sampling Interval (days) 0 7 14 29 61 90 124 Replicate A A A A A A A

Chlo rimuron ethyl (DPX

- F6025) 103.9 65.6 54.6 25.4 14.3 7.0 5.7

IN

- B4450 0.0 2.6 0.0 0.0 0.0 1.9 1.0

IN

- L8330 0.0 11.6 24.1 32.6 34.8 26.1 37.8

IN

- 00581 0.0 5.3 0.0 0.0 0.0 1.8 4.7

IN

- B7497 0.0 1.5 0.0 0.0 2.0 2.0 0.0

Met

- 1 3.4 4.1 3.4 8.4 4.7 5.1 0.0

Ot hers 0.0 2.8 0.0 1.8 3.6 8.3 3.0

Extracted residues 107.3 93.3 82.1 68.2 59.4 52.4 51.1

Unextracted residues 0.7 3.6 5.9 9.3 12.7 15.2 15.0

CO 2 

### n.a. 2.1 5.5 12.4 22.4 22.7 23.3 Organic Volatiles n.a. 0.0 0.0 0.0 0.0 0.0 0.0

Mass balance 108.0 99.0 93. 5 89.9 94.5 90.3 89.4 Data obtained from Table 4, p. 49, and Table 8, p. 53, of the study report. n.a. = not analyzed.

Table 7b. Transformation of [pyrimidine

- 2

- 14 

### C]chlorimuron ethyl, expressed as a percentage of the applied radioactivity, in an aerobic Illinois clay loam soil.
Sampling Interval (days) 0 7 14 29 61 90 124
Replicate A A A A A A A

Chlorimuron ethyl (DPX

- F6025) 94.8 69.9 55.0 26.7 13.2 9.1 6.4

IN

- N6186 3.4 6.4 9.8 20.1 19.1 17.1 18.9

IN

- L8330 0.0 12.0 22.8 32.3 33.5 35.9 39.4

IN

- V9662 0.0 0.5 2.2 2.7 2.2 0.0 0.0

Others 0.0 1.3 3.7 4.4 5.2 2.9 2.0

Extracted residues 98.1 90.1 93.5 86.1 73.1 65.1 66.6

Unextracted residues 0.6 3.0 3.2 4.8 9.9 10.5 12.4

CO 2 

### n.a. 0.3 1.1 3.1 9.4 12.2 14.9

Organic Volatiles n.a. 0.0 0.0 0.0 0.0 0.0 0.2

Mass balance 98.7 93.4 97.8 94.0 92.4 87.8 94.1 Data obtained from Table 5, p. 50, and Table 9, p. 54, of the study report. n.a. = not analyzed.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 11 of 21 

### Table 7c. Transformation of [phenyl

- U

14 

### C]chlorimuron ethyl, expressed as a percentage of the applied radi oactivity, in an aerobic North Dakota clay loam soil.
Sampling Interval (days) 0 7 14 29 61 90 124

Replicate A A A A A A A
Chlorimuron ethyl (DPX

- F6025) 96.9 64.8 59.4 27.0 28.2 19.3 16.1

IN

- B4450 0.0 2.0 2.6 0.0 9.7 13.5 41.3

IN

- L8330 0.0 2.4 5.2 4.1 5.9 6.8 3.7

IN

- 00581 0.0 15.3 22.9 46.3 37.7 42.8 30.6

IN

- B7497 0.0 2.4 0.0 0.0 0.0 0.0 0.0

Met

- 1 4.7 4.9 0.0 10.2 2.7 0.0 0.0

Others 0.0 4.4 4.6 0.0 4.8 0.0 0.0

Extracted residues 101.6 96.3 94.7 87.6 88.9 82.5 91.5

Unextracted residues 2.5 1.3 3.8 4.1 5.4 4.9 5.3

CO 2 

### n.a. 0.0 0.0 0.3 0.6 1.1 1.1

Organic Volatiles n.a. 0.0 0.0 0.0 0.0 0.0 0.0

Mass balance 104.1 97.6 98.5 92.0 94.9 88.5 97.9
Data obtained from Table 6, p. 51, and Table 10, p. 55, of the study report. n.a. = not analyzed.

Table 7 d. Transformation of [pyrimidine

- 2

- 14 

### C]chlorimuron ethyl, expressed as a percentage of the applied radioactivity, in an aerobic North Dakota clay loam soil.
Sampling Interval (days) 0 7 14 29 61 90 124

Replicate A A A A A A A
Chlorimuron ethyl (DPX

- F602 5) 99.9 79.1 68.4 52.1 33.3 30.7 21.4

IN

- N6186 0.0 13.5 19.5 34.0 45.3 49.5 56.9

IN

- L8330 0.0 0.0 3.0 4.1 4.9 2.7 4.6

IN

- V9662 0.0 0.0 0.0 0.0 0.0 0.0 0.0

Others 0.0 0.0 0.0 0.0 0.0 0.1 0.0

Extracted residues 99.9 92.6 90.9 90.2 83.5 83.1 82.8

Unextr acted residues 3.1 3.1 3.9 2.8 8.7 7.8 9.1

CO 2 

### n.a. 0.0 0.0 0.4 0.8 1.6 2.5

Organic Volatiles n.a. 0.0 0.0 0.0 0.0 0.0 0.0

Mass balance 103.0 95.7 94.8 93.4 93.0 92.5 94.4
Data obtained from Table 7, p. 52, and Table 11, p. 56, of the study report.

n.a . = not analyzed.



### E. Transformation of the Test Compound

Transformation kinetics of the parent compound in the total system are summarized in the following Figures , with transformation pr oduct information summarized in Table 8

.

Single First Order, First Order Multi

- Compartment, Hockey Stick, and Double First

- Order in Parallel models were used by the study author to predict DT50 values (p. 34). SFO DT50 values

were 15.6

- 18.3 days in the Il linois clay loam soil and 29.3

- 47.2 days in the North Dakota clay loam soil (p. 44).Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 12 of 21 K inetics models: Single First Order (SFO); Double First Order in Parallel (DFOP), and Indeterminate Order Rate Equation (IORE). Calculated half

- lives and model parameters in accordance with the NAFTA kinetics guidance (USEPA, 2012).



### Observed nonvolatile transformation products are described in Table 8

. S even transformation products were isolated , of which six were identified

. 

## Aerobic metabolism of Chlorimuron ethyl in Illinois clay loam soil

Days % AR

0
7
14 29 61 90
124 0 7
14 29 61 90 124 104. 65.6 54.6 25.4 14.3 7.00 5.70 94.8 69.9 55.0 26.7 13.2 9.10 6.40 0 20 40 60 80 100 120 0 20 40 60 80 100

TimeConcentration SFO

DFOP

IORE

-5 0 5

-5 0 5

-5 0 5

0 20 40 60 80 100 120

D T 50 D T 90  2 C 0 Parameters

SFO 16.9 56.2 8.9 96.1 k  0.041

DFOP 14.8 76.9 4.7 98.8 f  0.827   k 0  0.0587   k 1  0.0084

IORE 14.6 75.6 4.8 99.4 N  1.49   k  0.00589 S C

S S F O S l o w   t 1 2

t R 

 I O R E 150

328

82.5

22.8



### Aerobic metabolism of Chlorimuron ethyl in North Dakota clay loam soil

Days % AR

0
7
14 29 61 90
124 0 7
14 29 61 90 124 96.9 64.8 59.4 27.0 28.2 19.3 16.1 99.9 79.1 68.4 52.1 33.3 30.7 21.4 0 20 40 60 80 100 120 0 20 40 60 80

TimeConcentration SFO

DFOP

IORE

-20 -10 0 10 20

-20 -10 0 10 20

-20 -10 0 10 20

0 20 40 60 80 100 120

D T 50 D T 90  2 C 0 Parameters

SFO 39.2 130 13 86.8 k  0.0177

DFOP 21.9 237 4.4 97.9 f  0.572   k 0  0.0694   k 1  0.00615

IORE 22.8 348 4.3 98.4 N  2.43   k  7.34e-05 S C

S S F O S l o w   t 1 2

t R 

 I O R E 787

1.48e+03

113

105Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 13 of 21 

### Table 8. Transformation Products of Chlorimuron ethyl in Soil.

Transformation

Products Maximum %AR

Observed Associated Interval (days) Final %AR

Observed Final Interval (days)

Illinois USA Clay loam soil
(20 ° C, pH 5.5) IN

- B4450 2.6 7 1.0 124

IN

- L8330 39.4 124 39.4 124

IN

- 00581 5.3 7 4.7 124

IN

- B7497 2.0 61, 90 0.0 124

IN

- N6186 20.1 29 18.9 124

IN

- V9662 2.7 29 0.0 124

Met

- 1 8.4 29 0.0 124

North Dakota

USA Clay loam soil
(20 ° C, pH 5.9) IN

- B4450 41.3 124 41.3 124

IN

- L8330 6.8 90 4.6 124

IN

- 00581 46.3 29 30.6 124

IN

- B7497 2.4 7 0.0 124

IN

- N6186 56.9 124 5 6.9 124

Met

- 1 10.2 29 0.0 124

Data obtained from Tables 8

- 11, pp. 53

- 56, in the study report.



### An aerobic transformation pathway in soil was provided by the study author (Figure 40, p. 125).Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 14 of 21 

### III. STUDY DEFICIENCIES AND REVIEWER’S COMMENTS

1. Both soils used in the experiment were classified as clay loam and has similar pHs (Table 1, p. 46) . The North Dakota clay loam soil had more sand (34% vs 20%), a higher organic matter

conten t (4.7% vs 2.8%), and a higher CEC (24.3 vs 17.1 meq/100 g).

2. Transformation product M et

- 1 reached 10.2% of the applied at 29 days in North Dakota clay

loam soil but was not identified (Table 10, p. 55)

. The study author stated that it did not coelute

in HPLC or TLC with any standards and that purification with LC/MS analysis was unsuccessful (p. 42).

3. In three of the four experiments, overall recoveries were <90% of the applied at one or more sampling intervals (Tables 4

- 7, pp. 49

- 52).

4. Significant level s ( 12.4

- 15.2 % of the applied ; Tables 4

- 5, pp. 49

- 50 ) of unextracted residues

were detected in the Illinois clay loam soils, and the study author failed to use solvents with a range of dielectric constants (including a nonpolar solvent) to maximize extracti on of the

residues. Although it was reported that extracted soil containing >10% of the applied radioactivity was analyzed by organic matter fractionation (p. 26; Figure 4, p. 63), the method was not described and no results from such an analysis were repo rted.

5. The pesticide use history was not reported, and the soils were not show n to be pesticide

- free prior to use. Storage of the soils for the ca . 3 weeks between the time of collection and receipt at the testing laboratory were not reported.

IV. REFERE NCES

1. U.S. Environmental Protection Agency. 2008. Fate, Transport and Transformation Test Guidelines, OCSPP 835.4100, Aerobic Soil Metabolism. Office of Chemical Safety and Pollution Prevention, Washington, DC. EPA 712

- C

- 08

- 016.

2. U.S. Environmental Protect ion Agency. 2012. NAFTA Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 15 of 21 DER ATTACHMENT 1. Chlorimuron ethyl and Its Environmental Transformation Products

. A

Code Name/ Synonym Chemical Name Chemical Structure Study T ype MRID Maximum %AR (day) Final %AR (study length)

PARENT
Chlorimuron ethyl (DPX

F6025) IUPAC: Ethyl 2

- (4

- chloro

- 6

- methoxypyrimidin

- 2

- ylcarbamoylsulfamoyl)benzoate

CAS: Ethyl 2

- [[[[(4

- chloro

- 6

- methoxy

- 2

- pyrimidinyl)amino]carbonyl]amin o]sulfonyl]benzo ate

CAS No.: 90982

- 32

- 4

Formula: C 15 H 15 ClN 4 O 6 S

MW: 414.8 g/mol

SMILES: n1c(Cl)cc(OC)nc1NC(=O)NS(=O) (=O)c2ccccc2C(=O)OCC Cl O C H 3

N

N N

H O

N

H S O

O C H 2 C H 3

O O 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 103.9% ( 0 d) 6.4% (124 d)

North Dakota

C lay loam 99.9% ( 0 d) 21.4% (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 98.5% ( 0 d) 16 .4% (100 d)

River water:

Sand 97.0% ( 0 d) 34.5 % (100 d)

MAJOR (>10%) TRANSFORMATION PRODUCTS

IN

- L8330 IUPAC: Ethyl 2

- [(4

- ch loro

- 6

- hydroxy

- pyrimidin

- 2

- yl)carbamoylsulfamoyl]benzoate

Formula: C 14 H 13 ClN 4 O 6 S

MW: 400.8 g/mol

SMILES: [H]N(c1nc(cc(n1)Cl)O)C(=O)N([ H])S(=O)(=O)c2ccccc2C(=O)OC

C C H 2 C H 3

O

S

O O

H N O

H N N O H

Cl N O 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 39 .4% ( 124 d) 39.4% (124 d)

North Dakota

Clay loam 6.8% ( 90 d) 4.6% (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 66.6% ( 100 d) 66.6 % (100 d)

River water:

Sand 29.2% ( 79 d) 21.6 % (100 d)Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 16 of 21 Code Name/ Synonym Chemical Name Chemical Structure Study T ype MRID Maximum %AR (day) Final %AR (study length)

IN

- N6 186 IUPAC: 4

- Chloro

- 6

- methoxy

pyrimidin

- 2

- amine

Formula: C 5 H 6 ClN 3 O

MW: 159.6 g/mol

SMILES: [H]N([H])c1nc(cc(n1)Cl)OC

N H

H Cl O C H 3

N

N 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 20.1% ( 29 d) 18.9 % (124 d)

North Dakota

Clay loam 56.9% ( 124 d) 56.9% (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 2.9% ( 7 d) 0.0% (100 d)

River water:

Sand 33.0% ( 100 d) 33.0 % (100 d)

IN

- B4450 IUPAC: Ethyl 2

- sulfamoylbenzoate

Formula: C 9 H 11 NO 4 S

MW: 229.2 g/mol

SMILES: [H]N([H])S(=O)(=O)c1ccccc1C(= O)OCC C H 2 C H 3

O

S

O O

H N H O 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 2.6% ( 7 d) 1.0% (124 d)

North Dakota

Clay loam 41.3 % ( 124 d) 41.3 % (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 1.0 % ( 28 d) 0.0% (100 d)

River water:

Sand 39.8% ( 100 d) 39.8 % (100 d)

IN

- 00581 (Saccharin) IUPAC: 1,1

- Dioxo

- 1,2

- benzothiazol

- 3

- one

Formula: C 7 H 5 NO 3 S

MW: 183.2 g/mol

SMILES: [H]N1C(=O)c2ccccc2 S1(=O)=O O

N H

S O

O 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 5.3 % ( 7 d) 4.7 % (124 d)

North Dakota

Clay loam 46.3 % ( 29 d) 30.6 % (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay l oam 6.5 % ( 100 d) 6.5 % (100 d)

River water:

Sand 32.1% ( 100 d) 32.1 % (100 d)

Met

- 1

NA Structure not provided 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 8.4 % ( 29 d) 0.0 % (124 d)

North Dakota

Clay loam 10.2 % ( 29 d) 0.0% (124 d)Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 17 of 21 Code Name/ Synonym Chemical Name Chemical Structure Study T ype MRID Maximum %AR (day) Final %AR (study length)

Carbon dioxide IUPAC: Carbon dioxide

Formula: CO 2 MW: 44 g/mol

SMILES: C(=O)=O

C O O 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 23.3% ( 124 d) 23.3% (124 d)

North Dakota

Clay loam 2.5% ( 124 d) 2.5 % (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water:

Sand 0.7 % ( 79 d) 0.6 % (100 d)

Unextractable residues

NA NA 835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 15.2 % ( 90 d) 15.0 % (124 d)

M INOR (< 10%) TRANSFORMATION PRODUCTS

IN

- B7497 IUPAC: Ethyl 2

- (carbamoylsulfamoyl)benzoate

Formula: C 10 H 12 N 2 O 5 S

MW: 272.3 g/mol

SMILES: [H]N([H])C(=O)N([H])S(=O)(=O) c1ccccc1C(=O)OCC C H 2 C H 3

O O

S O

N H

H

O N

H O 835.4100

Aerobic soil

metabolism 49526701 Illinoi s Clay loam 2.0% ( 61

- 90 d) 0.0% (124 d)

North Dakota

Clay loam 2. 4 % ( 7 d) 0.0 % (124 d)

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 2.9 % ( 62 d) 2.1 % (100 d)

River water:

Sand 3.2 % ( 79

- 100 d) 3.2 % ( 100 d)Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 18 of 21 Code Name/ Synonym Chemical Name Chemical Structure Study T ype MRID Maximum %AR (day) Final %AR (study length)

IN

- V9662 IUPAC: (4

- Chloro

- 6

- methoxy

pyrimidin

- 2

- yl)urea

Formula: C 6 H 7 ClN 4 O 2 MW: 202.6 g/mol

SMILES: [H]N([H])C(=O)N([H])c1nc(cc(n1 )Cl)OC N

O N

H H N H

N Cl O C H 3

835.4100

Aerobic soil

metabolism 49526701 Illinois Clay loam 2. 7 % ( 29 d) 0.0% (1 24 d)

IN

- H1427 IUPAC: 2

- Amino

- 6

- methoxy

pyrimidin

- 4

- ol

Formula: C 5 H 7 N 3 O 2 MW: 141.1 g/mol

SMILES: [H]N([H])c1nc(cc(n1)OC)O N

N

H H

N O H O C H 3

835.4300

Aerobic aquatic

metabolism 49526702 River water: Clay loam 2.0 % ( 100 d) 2.0 % (100 d)

River water:
Sand 4.0 % ( 79 d) 1.4 % (100 d)

REFERENCE COMPOUNDS NOT IDENTIFIED

IN

- H9235 IUPAC: 2

- Amino

- 6

- methoxy

pyrimidin

- 4

- ol

Formula: C 5 H 7 N 3 O 2 MW: 141.1 g/mol

SMILES: [H]N([H])c1nc(cc(n1)OC)O N H

H

O H O

C H 3 N

N 835.4100

Aerobic soil

metabolism 4952 6701 NA NA

IN

- D5119

- 001 IUPAC: 2

- Sulfamoylbenzoic acid

Formula: C 7 H 7 NO 4 S

MW: 201.2 g/mol

SMILES: [H]NS(=O)(=O)c1ccccc1C(=O)O O

O H

S O

O

N

H 835.4100

Aerobic soil

metabolism 49526701 NA NA

IN

- F8174

- 001

NA Structure not provided 835.4100

Aerobic soil

metabolism 49526701 NA NA

A AR means “applied radioactivity”. MW means “molecular weight”. NA means “not applicable”.Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 19 of 21 

### Attachment 2: Statistics Spreadsheets and GraphsChlorimuron ethyl (PC 128901 ) MRID 49526701

Page 20 of 21 

### DER Attachment 3: Calculation s

Calculations were performed by the re viewer using PestDF, 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 PestDF 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)

wher e, N = order of decline rate (

- )

k IORE 

### = IORE rate constant of decline (d

- 1 

### )

This equation is solved with PestDF by adjusting C 0 

### , k IORE 

### , and N to minimize the objective function for IORE (SIORE) (See equation 9). Half

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

- order half

- life that passes through the DT 90 

### of the IORE model. (Traditional DT 50 

### and DT 90 

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

(eq. 5)

DT 50 

### = 1)

- k(N C

- /2) (C N)

- (1 0 N)

- (1 0 

### (eq. 6)

DT 90 

### = 1)

- k(N C

- /10) (C N)

- (1 0 N)

- (1 0 

### (eq. 7)Chlorimuron ethyl (PC 128901 ) MRID 49526701

Page 21 of 21 

### 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 compartmen t 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

kinetics 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 calcul ated 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 kineti cs 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 c ase) α = the confidence level (0.50 in this case) F(α, p, n

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

- p