### Test Material: Nicosulfuron

MRID 48790905

Title: Allan, J. 2012. Anaerobic aquatic metabolism of 14 

### C-nicosulfuron (DPXV9360) in two water/sediment systems

EPA PC Code: 129008

OCSPP Guideline: 835.4400

For Cambridge Environmental

Primary Reviewer: Lynne Binari Signature:

Date: 10/23/12

Secondary Reviewer: Kathleen Ferguson Signature:

Date: 10/23/12

QC/QA Manager: Joan Gaidos Signature:

Date: 10/23/12Nicosulfuron (PC 129008) MRID 48790905

Page 3 of 28 

### analyzed), a maximum of 8.2% at 14 days and 1. 5-1.6% at 102 days. In the silt loam system,

nicosulfuron in the water column decreased from 95.5-100.3% at day 0 to 43.1-47.6% at 102 days,

while nicosulfuron in the sediment was 3.8-4.9% (maximum 4.9%) at day 0 and 2.1-2.5% at 102 days.

Observed DT 50 

### values, calculated half-lives, and inform ation on transformation products are listed

in Table 1 . Nicosulfuron transformation rates and pr oduct profiles were similar between the two sediment types.

In the sand sediment (combined labels), extracta ble radioactivity increased from 0.6-1.6% of the applied at day 0 to maximums of 10.3-10.4% at 14 days (pyridine label) and 80 days (pyrimidine label) and was 8.4-9.4% at 102 days, while unextracted radioa ctivity increased from 0.0% (n = 2) at day 0 to 17.8-20.2% at study term ination. At study termination, ≤ 0.2%, 6.7-7.2% and 6.4-8.2% of the applied was associated with the fulvic acids, humic acids and humin, re spectively. Total evolved

14 

### CO 2 

### amounted to 2.0-4.6% of the applied.

In the silt loam sediment (combined labels), ex tractable radioactivity in creased from 0.6-0.7% of the applied at day 0 to maximums of 9.1-9.8% at 80 days and was 7.0- 7.8% at 102 days, while unextracted radioactivity increased from 0.1-0.2% at day 0 to 27.0-28.9% at study termination. At study termination, 0.1% (n = 2), 9.7-10.4% and 10.7-14.8% of the app lied was associated with the fulvic acids, humic acids and hum in, respectively. Total evolved 14 

### CO 2 

### amounted to 0.1-0.5% of the applied.

Table 1. Results Synopsis: Anaerobic Aquatic Metab olism of Nicosulfuron in the Total System

Total System 1 Observed

DT 50 (days) Calculated

Half-life

(days) Model

Parameters and

Statistics 2 Transformation Products Common Name (maximum % of applied observed, associated interval) 3

Major Minor

Georgia natural

water:sand sediment system (20°C, water pH 7.6, sediment pH 7.6) ca . 101 101 C 0 = 101

k = 0.00685

S

c = 322

S SFO = 287

r 2 = -- (SFO) IN-37740 (13.9%, 80 days) Unextracted residues (pyridine

label 20.2%, pyrimidine label 17.8%, 102 days) IN-R5Q09 (6.6%, 102 days) IN-V9367 (4.8%, 102 days)

CO 2 (pyridine label 2.0%,

pyrimidine label 4.6%, 102 days)

Missouri natural

water:silt loam sediment system (20°C, water pH 7.9, sediment pH 7.8) ca . 95 92.3 C 0 = 102

k = 0.00751

S

c = 213

S SFO = 179

r 2 = -- (SFO) IN-37740 (13.0%, 80 days) Unextracted residues (pyridine

label 28.9%, pyrimidine label 27.0%, 102 days) IN-R5Q09 (5.8%, 102 days) IN-V9367 (4.2%, 102 days)

CO 2 (pyridine label 0.5%,

pyrimidine label 0.1%, 102 days)
1 Sampling site not described (pond, lake, river, ditch, rice paddy, etc.). 2 Calculated half-lives and model parameters for the best fit kinetics models in accordance with the NAFTA kinetics

guidance (USEPA, 2011); -- = not calculated; SFO = Simple First Order. 3 IN-37740 and IN-R5Q09 contained both pyridine and pyrimidine labels; IN-V9367 contained pyridine label.Nicosulfuron (PC 129008) MRID 48790905

Page 4 of 28 

### I. Materials and Methods

A. Materials [Pyridine-2- 14 

### C]- and [pyrimidine-2- 14 

### C]-labeled nicosulfuron (p. 18).

1. Test Materials: [Pyridine-2- 14 

### C]-label Specific activity: 42.71 μCi/mg

N O CH 3

O CH 3 N N H

O N H

S O

O

N N C H 3

C H 3 O

* 

### Radiochemical purity: >95% (pp. 18, 33; Figure 5A, p. 67) Chemical purity: Not reported

Lot/Batch No.: 3638105

[Pyrimidine-2- 14 

### C]-label

N N O CH 3

O CH 3 N N H

O N H

S O

O N C H 3

C H 3 O * 

### Specific activity: 42.67 μCi/mg Radiochemical purity: >98% (pp. 18, 33; Figure 5B, p. 68) Chemical purity: Not reported

Lot/Batch No.: 3638127

Solubility in water: 7.4 g/L at 25oC (p. 18).

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

Table 2. Reference Compounds 1

Applicant’s Code Name (synonyms) Chemical Name (CAS) Purity (%) Lot No.

Nicosulfuron (DPX-V9360) 2-[[[[(4,6-Dimethoxy-2-pyrimidinyl)amino]carbonyl]- amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamide 98.3 E105819-003

IN-V9367 2-(Aminosulfonyl)-N,N-dimethyl-3-pyridinecarboxamide 99.7 005
IN-64554 Isothiaxolo[5,4-B]pyridin-3(2H)-one,1,1-dioxide 99.3 D100082-298C

IN-37740 2-[[(3,4-Dihydro-6-methoxy-4-oxopyrimidin-2-yl]aminocarbonyl]aminosulfonyl]-N,N-dimethyl-3-pyridinecarboxamide 98.1 E106951-071B

IN-J0290 4,6-Dimethoxy-2-pyrimidinamine 99.9 9964-098

IN-GDC42 2[[[[(Aminocarbonyl)amino]carbonyl]amino]sulfonyl]-N,Ndimethyl-3-pyridinecarboxamide 96.3 001

IN-77799 2-[(Aminocarbonyl)[4-methoxy-6-(methyldioxy)-2- pyrimidinyl]amino] -N,N-dimethyl-3-py ridinecarboxamide 98.7 E105318-116

IN-HYY21 2-[[[[(Aminoiminomethyl)amino]carbonyl]amino]sulfonyl]- N,N-dimethyl-3-pyridinecarboxamide 90.3 004

Data obtained from p. 19; Figure 1, pp. 58-60 of the study report. Nicosulfuron CAS name not provided in study report (pp. 17-18; Figure 1, p. 58); CAS name obtained from file Nicosulfuron structures[1].doc. 1 Reference compounds provided by DuPont (p. 19).Nicosulfuron (PC 129008) MRID 48790905

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### 3. Water:Sediment: Water and sediment collection and ch aracterization are summarized in Table

3 and Tables 4a-4b , respectively.

Table 3. Water:Sediment Collection and Storage

Description Tift Boonville

Geographic location Chula, Tift County, Georgia, U.S.A.; sampling site not

described Boonville, Cooper County, Missouri, U.S.A.; sampling site

not described

Pesticide use history at the collection site Not reported

Collection date Not reported

Collection procedures Water: Not reported

Sediment: Not reported

Storage conditions Water: Not reported

Sediment: Stored at ca . 4oC in darkness; no additional details were provided

Storage length Less than one month

Preparation Water: Water and sediment ca . 2-mm sieved Sediment:
Data obtained from pp. 20, 32 of the study report.



### Table 4a. Parameters for Characterizati on of Water:Sediment Samples – Tift

Parameter (unit) Field Sampling/Post Handling Stage of Test Procedure 1

Prior to Test 2 During Test End of Test

Water Temperature (oC) -- pH 7.6 7.905, 7.790 7.422-8.607 8.478, 8.664 TOC (mg/L)

-- -- -- O 2 (mg/L) -- 0.48, 0.33 0.08-1.13 0.21, 0.14 Redox potential (mV) -189.8, -176.3 -225.1 to -36.2 -219.1, -122.7

Sediment Sampling Depth (cm) Not reported
pH 7.6 3 7.195, 7.140 7.087-7.356 7.465, 7.534 Soil Texture (USDA) Sand

Particle Size Distribution 94% sand (2000-50 μm) 4% silt (50-2 μm) 2% clay (<2 μm) TOC (mg/L)

-- -- Organic matter (%, Walkley Black) 1.3 Organic carbon (%) 4 0.756 CEC (meq/100 g) 5.0

Soil moisture (%) at 1/3 bar: 4.7

15 bar: 2.9 Bulk density, disturbed (g/cc) 1.22 Microbial biomass (μg/g dry wt.) 5 92.9 25.1 Redox potential (mV) -223.4, -220.3 -272.2 to -133.2 -231.6, -196.1 Data obtained from p. 32; Tables 1A-B, pp. 40-41; Table 4A, p. 45 of the study report. Soil texture confirmed by the reviewer using USDA-NRCS technical support tools. -- = Not reported. 1 System parameters (pH, oxygen concentration, redox potentia l) measured in treated system s at each collection interval (p. 25; Table 4A, p. 45). Measurements taken using a WTW Multi 3430 IDS (intelligent digital sensor); for redox potential, reference electrode was not specified (p. 20). 2 Day 0 posttreatment interval. 3 In 1:1 soil:water ratio (Table 1A, p. 40).Nicosulfuron (PC 129008) MRID 48790905

Page 6 of 28 4 Percent organic carbon determined by the study author using the following formula: organic carbon (%) = organic

matter (%) ÷ 1.72 (Table 1A, p. 40). 5 Fumigation and extraction method (pp. 21, 32). Measured in sediment from untreated test systems (p. 22).



### Table 4b. Parameters for Characterization of Water:Sediment Samples – Boonville

Parameter (unit) Field Sampling/Post Handling Stage of Test Procedure 1

Prior to Test 2 During Test End of Test

Water Temperature (oC) -- pH 7.9 7.415, 7.680 7.294-8.106 8.153, 8.248 TOC (mg/L)

-- -- -- O 2 (mg/L) -- 0.33, 0.47 0.00-0.53 0.14, 0.13 Redox potential (mV) -161.0, -160.9 -227.9 to -146.6 -240.6, -245.6

Sediment Sampling Depth (cm) Not reported pH 7.8 3 7.229, 7.230 7.134-7.341 7.336, 7.332 Soil Texture (USDA) Silt Loam

Particle Size Distribution 18% sand (2000-50 μm) 56% silt (50-2 μm) 26% clay (<2 μm) TOC (mg/L)

-- -- Organic matter (%, Walkley Black) 3.2 Organic carbon (%) 4 1.86 CEC (meq/100 g) 15.3

Soil moisture (%) at 1/3 bar: 33.4

15 bar: 17.2 Bulk density, disturbed (g/cc) 0.93 Microbial biomass (μg/g dry wt.) 5 51.6 42.9 Redox potential (mV) -246.9, -236.3 -254.1 to -189.9 -239.0, -249.5 Data obtained from p. 32; Tables 1A-B, pp. 40-41; Table 5A, p. 46 of the study report. Soil texture confirmed by the reviewer using USDA-NRCS technical support tools. -- = Not reported. 1 System parameters (pH, oxygen concentration, redox potentia l) measured in treated system s at each collection interval (p. 25; Table 5A, p. 46). Measurements taken using a WTW Multi 3430 IDS (intelligent digital sensor); for redox potential, reference electrode was not specified (p. 20). 2 Day 0 posttreatment interval. 3 In 1:1 soil:water ratio (Table 1A, p. 40). 4 Percent organic carbon determined by the study author using the following formula: organic carbon (%) = organic

matter (%) ÷ 1.72 (Table 1A, p. 40). 5 Fumigation and extraction method (pp. 21, 32). Measured in sediment from untreated test systems (p. 22).Nicosulfuron (PC 129008) MRID 48790905

Page 7 of 28 

### B. Study Design

1. Experimental Conditions: Table 5 summarizes the experimental conditions.

Table 5. Experimental Design

Experimental Design Tift Boonville
Duration of the test 246 days

Water:

Type and size of filter used Not reported.
Amount of sediment and water per treatment:

Water 411 g total; 355 mL added + ca

. 56 g associated with sediment 422 g total; 355 mL added + ca

. 67 g associated with sediment.
Sediment 191 g wet wt., ca . 135 g dry wt. 143 g wet wt., ca . 76.1 g dry wt.

Water/sediment ratio Total Water:Dry wt. 3:1 (411 g:135 g dry wt.) 5.5:1 (422 g:76.1 g dry wt.)
Water added:Wet wt. 1.9:1 (355 mL:191 g wet wt.) 2.5:1 (355 mL:143 g wet wt.)
Application rates:
Nominal 0.3 mg a.i./L

Actual 1 0.255 mg/L (0.105 mg in 411 g total water) 0.249 mg/L (0.105 mg in 422 g total water)
Number of replicates:

Control, if used Sterile controls were not used.

Treated Per system and label type, eleven water-sediment systems were treated to allow for a single system per label/system type at each of eight sampling intervals, plus reserves.

Test apparatus:

Type/material/volume Nalgene bottles (500-mL), containing the water-sediment system, connected in series (sample train pe r system/label type) to a continuous flow-through (humidified nitrogen, flow rate not reported) volatiles trapping system (Figure 2, p. 61).

Details of traps for CO 2 and organic volatile, if

any In sequence as follows: Supelco ORBO-32 tube (one trap) to collect organic volatiles and 1M KOH solution (two traps) to collect CO 2 ; trapping solution volumes not reported.
If no traps were used, is the system closed? Volatiles traps were used.
Identity and final concentration (based on water volume) of co-solvent Acetonitrile:0.01M ammonium acetate (50:50, v:v); 0.1% ACN by volume (793-802 μL of 50:50 test solution/411-422 g total water).
Test material application method:

Volume of the test solution

used/treatment Pyridine label 793 μL
Pyrimidine label 802 μL
Application method ( i.e. , mixed/not mixed) Applied just below wate r layer surface using a 100-1,000-μL pipette
Any indication of the test material adsorbing to the walls of the test apparatus? None; 99.6-101.6% of the applied recovered in water layers at day 0

posttreatment Microbial biomass/population of control units: Sterile controls were not used.

Water --

Sediment --
Microbial biomass/population of treated : Not determined in treated systems

Water --

Sediment --
Experimental conditions:

Temperature 20 ± 2  C
Continuous darkness (yes/no) Yes
Other details (if any) The wate r:sediment systems were acclimat ed to test conditions for 7Nicosulfuron (PC 129008) MRID 48790905

Page 8 of 28 Experimental Design Tift Boonville
days prior to treatment; anaerobic conditions were defined as a dissolved oxygen content of <2 mg O 2 /L.

Additional untreated water:sediment systems were prepared and maintained for microbial biomass (six systems per sediment type) and system parameter (pH, oxygen concentration, redox potential; two "control" systems per sediment type) determinations.

Two months after initiation of the definitive experiment, additional systems were treated at a 10x rate (1.05 mg a.i./system) for both labels and incubated as described above; no additional details were provided.

The nominal test application rate of 0.3 mg a.i./L used in this study was selected to allow for an adequate amount of material to follow the degradation of nicosulfuron. No comparison to the maximum field use rate for nicosulfuron was provided. Data obtained from pp. 17-18, 21-24, 26; Table 2, p. 42; Table 4B, p. 45; Table 5B, p. 46; Tables 6-7, pp. 47-48; Figure 2, p. 61 of the study report. 1 For both labels 0.105 mg/system applied, based on 793 μL of 0.1325 mg/mL [pyridine-2- 14 C]nicosulfuron test

solution, and 802 μL of 0.1310 mg/mL [pyrimidine-2- 14 C]nicosulfuron test solution (p. 22).



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

Table 6. Sampling during Study Period

Parameter Details

Sampling intervals (duration) 0, 3, 7, 14, 31, 60, 80 and 102 days

Sampling method Per system and label type, a single sample was collected at each sampling interval

Method of collection of CO 2 and organic volatile compounds Volatiles traps were collected and replaced at each sampling interval after day 0

Sampling Intervals/Times

Redox potential in water layer

Measured in treated systems coll ected at each sampling interval. Probes were placed in the water phase or just below surface of

sediment. Dissolved oxygen in water layer

pH in water layer

Redox potential in sediment

pH in sediment

Other details, if any The water layer was decanted and sediments extracted the day of collection. Water layers were filtered and "typically" analyzed within

24 hours of collection. Sediment extracts were "typically" analyzed by HPLC within one week of collection. Following LSC analysis, water layers and sediment ex tracts were stored frozen.

10x rate systems: Aliquots (10 mL) were taken from the water layers of the [pyridine-2- 14 C]-label treated sand se diment (Tift) and the [pyrimidine-2- 14 C]-label treated silt loam sediment (Boonville) systems at 79 days posttreatment.
Data obtained from pp. 24, 37; Tables 6-7, pp. 47-48 of the study report.Nicosulfuron (PC 129008) MRID 48790905

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### 3. Analytical Procedures:

Separation of the Water and Sediment: The water layer was separated from the sediment by decanting (p. 25).

Extraction/Clean Up/Concentration Methods: Water layer . An aliquot ( ca . 5 mL) of the water layer was filtered (0.45-μm nylon syri nge filter), then triplicate a liquots (1 mL) of unfiltered and filtered water were analyzed for total radioactivity by LSC to confirm post-filtration recoveries of 90-110% (p. 25; Appendix 1, p. 105). Filtered water samples were analyzed directly using HPLC.

Sediment was extracted three times with acetone:0.1M ammonium carbonate (80:20, v:v) via shaking (Eberbach reciprocating shaker, "low speed ") for 30 minutes/extraction; extraction solvent volumes were 160 mL (pp. 20, 25). Sediment and extract were separated by centrifugation ( ca

. 4,800 rpm, 10 minutes). Extracts we re combined, brought to volume ( ca . 480 mL) with extraction solvent, and aliquots (1 mL, replicates not re ported) analyzed by LSC (p. 25; Appendix 1, p. 105). An aliquot (50-100 mL) was concen trated to dryness (method not specified), with the residues reconstituted in 0.1% formic acid:methanol (95: 5, v:v, 5 mL), filtered (0.45-μm) and analyzed by HPLC (Figure 3, p. 62).

Determination of Unextracted Residues: Extracted sediment was dried under a nitrogen stream, homogenized (method not specified) , then triplicate aliquots ( ca . 0.5g) were analyzed for total radioactivity by LSC following combustion (p. 26 ; Appendix 1, p. 105). Oxidizer efficiency was reported as 95-105% (p. 27).

Organic matter fractionation . Day 102 extracted sediment was fu rther characterized using standard organic matter fractionation techniques (p. 26). Fulv ic acid and humic acid fractions were analyzed for total radioactivity by LSC, and the humin by LSC following combustion.

Determination of Volatile Residues: Triplicate aliquots (1 mL) of the KOH trapping solutions were analyzed for total radioactivity using LSC (p. 24; Appendix 1, p. 106). The ORBO-32 tubes were not analyzed (p. 26).

Total Radioactivity Measurement: Total 14 

### Cresidues were determined by summing the

concentrations of residues measured in the water layers, sediment extracts, extracted sediment and trapping solutions (pp. 29-30).

Derivatization Method A derivatization method was not employed.

Identification and Quantification of Parent Compound: Water layer and sediment extract samples were analyzed by HPLC (Agilent System s) using a Phenomenex Luna C18(2) column (4.6 x 150 mm, 5 μm) eluted with a gradient mobile phase of (A) 0.1% formic acid and (B) methanol (pp. 27-28). The eluent was monito red with radioactivity and UV (254 nm) detectors. Components were quantified and column recove ries determined by fraction collec tion (interval not specified) and LSC analysis (p. 27). Column recoveries were reported as within ca . 90-110% for all samples (p. 33). Parent [ 14 

### C]nicosulfuron was identified by comparison to the relative retention time of unlabeled reference standard (p. 27; Fi gure 4A, p. 63; Figures 8A-11G, pp. 73-88).Nicosulfuron (PC 129008) MRID 48790905

Page 10 of 28 

### Identification of [ 14 

### C]nicosulfuron in the wate r layer of 10x rate systems was confirmed against reference standard by LC/MS/MS-ESI + 

### (electrospray ionization, pos itive ion mode, m/z 411) using a Phenomenex Luna C18 column (4.6 x 150 mm, 5 μm) eluted with a gradient mobile phase of (A) 0.1% aqueous formic acid and (B) acetonitrile (pp. 28-29, 36; Figures 12A-12C, pp. 89-91).

Identification and Quantification of Transformation Products: Transformation products were separated and quantified using HPLC as describe d for parent (pp. 27-28; Figures 4B-4H, pp. 63-66; Figures 8A-11G, pp. 73-88). Identification of product [ 14 

### C]IN-37740 (m/z 397) in the water layer of 10x rate systems was confirmed agains t reference standard by LC/MS/MS-ESI + 

### as described above (pp. 28-29, 36; Figures 12D-12F, pp. 92-94). Also using LC/MS/MS-ESI + 

### , a structure for product [ 14 

### C]IN-R5Q09 (m/z 383) was proposed based on mo lecular weight and fragmentation pattern (p. 36; Figures 12G-12J, pp. 95-98).

Detection Limits (LOD, LOQ) for the Paren t Compound and Transformation Products:

Table 7 summarizes limits of detection and quantitati on as determined using the method of Currie (pp. 31, 39).

Table 7. Limits of Detection (LOD) and Quantita tion (LOQ), Expressed as Percentage of the Applied Radioactivity (Combined Labels)

Sample Type LOD LOQ HPLC analyses Aqueous 0.075-0.077 0.31 Organic 0.010 0.041 LSC analyses KOH trap 0.0047 0.017 Aqueous layer 0.046 0.18 Organic extracts 0.061-0.062 0.23-0.24

Soil combustions Sand (Tift): 0.054-0.055 0.20 Silt Loam (Boonville): 0.039-0.040 0.14 Data obtained from Table 3, p. 44; Appendix 3, pp. 129-130 of the study report.



### II. Results and Discussion

A. Data:

Study results, including total mass balances and di stribution of radioactiv ity, are presented in

Tables 8a and 8b . The incubation temperature was re portedly maintained throughout the experiment (p. 32). System parameters (redox po tential, dissolved oxygen, pH) measured in the [ 14 

### C]nicosulfuron treated systems were comparable to untreated ("control") systems (Tables 4A-5B, pp. 45-46). For the treated systems (sand and silt lo am), dissolved oxygen was detected at nearly all intervals during the 102-day study, but pE + pH was <12 at all intervals fo r the water column and sediment (DER Attachment 2). Microbial bioma ss determinations of se diment from untreated systems indicated both sediments were viable at initiation and te rmination (pp. 26, 32).

Sand sediment (Tift) system (combined labels) . In the water column, redox potential, dissolved oxygen and pH were -189.8 to -176.3 mV, 0.33-0. 48 mg/L and 7.790-7.905, respectively, at day 0 posttreatment and -219.1 to -122.7 mV, 0.14-0.21 and 8.478-8.664, respectively at 102 days (Table 4A, p. 45). In the sediment, redox potential and pH were -223.4 to -220.3 mV and 7.140-7.195, respectively, at day 0 and -231.6 to -196.1 mV and 7.465-7.534, respectively, at study termination.Nicosulfuron (PC 129008) MRID 48790905

Page 11 of 28 

### Silt loam sediment (Boonville) system (combined labels) . In the water column, redox potential, dissolved oxygen and pH were -161.0 to -160.9 mV, 0.33-0.47 mg/L and 7.415-7.680, respectively, at day 0 posttreatment and -245.6 to - 240.6 mV, 0.13-0.14 and 8.153-8.248, respectively at 102 days (Table 5A, p. 46). In the sediment, redox potential and pH were -246.9 to -236.3 mV and 7.229-7230, respectively, at day 0 and -249.5 to -239.0 mV and 7.332-7.336, respectively, at study

termination.

B. Mass Balance:

In the sand sediment (Tift) system (combined labels) , recoveries ranged from 101.2 to 106.9% of the applied (Table 6, p. 47). Recoveries of total residues did not decrease over time and were within guideline criteria. In the wate r column nicosulfuron decreased from 95.2-97.1% of the applied at day 0 to 43.9-52.4% at 102 days (Table 8A, p. 49; Table 9A, p. 51). In the sediment nicosulfuron was 2.7-4.4% of the applied at 3 days (day 0 not analyzed), a maximum of 8.2% at 14 days, and 1.5-1.6% at 102 days.

In the silt loam sediment (Boonv ille) system (combined labels) , recoveries ranged from 100.6 to 105.6% of the applied (Table 7, p. 48). Recoveries of total residues did not decrease over time and were within guideline criteria. In the water column nicosulfur on decreased from 95.5-100.3% of the applied at day 0 to 43.1-47.6% at 102 days (Table 10A, p. 53; Table 11A, p. 55). In the sediment nicosulfuron was 3.8-4.9% of the applied at 3 days (day 0 not analyzed, maximum 4.9%) and 2.1- 2.5% at 102 days.

C. Bound and Extractable Residues:

In the sand sediment (Tift) , extractable radi oactivity (combined labels) increased from 0.6-1.6% of the applied at day 0 to maximums of 10.3-10.4% at 14 days (pyridine label, "PY") and 80 days (pyrimidine label, "MD") and was 8.4-9.4% at 102 days (Table 6, p. 47). Unextracted radioactivity increased from 0.0% (n = 2) of the applied at day 0 to maximums of 17.8-20.2% at study termination. Organic matter fractionation (102 days) found 0.0-0.2%, 6.7-7.2% and 6.4-8.2% of the applied associated with the fulvic acids, humic aci ds and humin, respectively (Table 12A, p. 57).

In the silt loam sediment (Boonville) , extractable radioactivity (com bined labels) increased from 0.6-0.7% of the applied at day 0 to maximums of 9.1-9.8% at 80 days and was 7.0-7.8% at 102 days (Table 7, p. 48). Unextracted radioactivity increa sed from 0.1-0.2% of th e applied at day 0 to maximums of 27.0-28.9% at study termination. Or ganic matter fractionation (102 days) found 0.1% (n = 2), 9.7-10.4% and 10.7-14.8% of the applied associ ated with the fulvic acids, humic acids and humin, respectively (Table 12B, p. 57).

D. Volatilization:

For the pyridine and pyrimidine la bels at study termination, volatile 14 

### CO 2 

### totaled 2.0% and 4.6% of the applied, respectively, in the sand sediment (Tift) system and 0.5% and 0.1%, respectively, in the silt loam sediment (Boonville) system (Tables 6- 7, pp. 47-48). The ORBO tubes were not analyzed for other volatile compounds (p. 26).Table 8a. Transformation of Nicosulfuron, Expressed as Percentage of the Applied Radioactivity, in Anaerobic Natural Water:SandSediment System1Sampling Interval (days) 0 3 7 14 31 60 80 102Replicate Number2PY MD PY MD PY MD PY MDPY MD PY MD PY MD PY MDNicosulfuron 97.1 95.2 101.0 100.4 96.9 99.3 89.7 98.0 80.5 91.6 62.5 66.0 55.8 62.6 45.5 53.9IN-377400.0 0.0 0.0 0.0 0.0 0.0 0.9 0.0 8.8 4.6 13.3 13.113.912.7 13.1 11.1IN-R5Q0930.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2.1 2.0 5.8 3.56.65.4IN-V9367 0.0 n.a. 0.0 n.a. 0.0 n.a. 0.9 n.a. 2.4 n.a. 2.3 n.a. 4.2 n.a.4.8n.a.Total other unknowns42.5 5.5 2.8 0.9 4.9 1.4 9.6 1.2 6.3 1.8 6.8 4.4 7.2 8.7 13.5 11.5Uncharacterized extractedresidues51.6 0.6Extracted residues1.6 0.6 4.5 2.8 3.8 2.2 10.3 2.8 7.1 5.5 8.9 8.4 9.6 10.4 9.4 8.4Unextracted residues 0.0 0.0 0.1 0.1 0.4 0.1 1.3 0.5 4.0 1.8 11.0 10.4 15.4 11.220.217.8Fulvic acidsn.p.0.2 0.0Humic acids7.2 6.7Humin8.2 6.4CO26n.p. n.p. 1.9 4.5 1.9 4.5 2.0 4.5 2.0 4.5 2.0 4.5 2.0 4.5 2.04.6Other volatile compounds ORBO tubes were not analyzed.Mass balance 101.2 101.3 105.8 105.9 104.1 105.4 103.5 104.9 104.4 105.5 103.0 105.0 104.8 103.9 106.5 106.9Data obtained from Table 6, p. 47; Table 8A, p. 49; Table 9A, p. 51; Table 12A, p. 57 of the study report.n.a. = Not applicable.n.p. = Not performed.1 Sampling site not described (pond, lake, river, ditch, rice paddy, etc.).2 PY = pyridine label, MD = pyrimidine label.3 Tentative identification based on LC/MS/MS molecular weight and fragmentation pattern (p. 36).4 Comprised of up to seventeen components, with no individual component >5.1% of applied in total system (Table 8A, p. 49; Table 9A, p. 51; Figures 8A-9G, pp. 73-80).5 Sediment extracts not analyzed by HPLC.6 Per label, all samples were connected to the same set of volatile traps.Nicosulfuron (PC 129008) MRID 48790905Page 13 of 28Table 8b. Transformation of Nicosulfuron, Expressed as Percentage of the Applied Radioactivity, in Anaerobic Natural Water:SiltLoam Sediment System1Sampling Interval (days) 0 3 7 14 31 60 80 102Replicate Number2PY MD PY MD PY MD PY MDPY MD PY MD PY MD PY MDNicosulfuron 95.5 100.3 98.7 102.6 96.2 101.7 92.2 92.6 75.7 82.8 59.8 69.6 52.6 57.7 45.6 49.7IN-377400.0 0.0 0.0 0.0 0.0 0.0 2.0 0.9 7.4 5.7 9.8 10.413.012.2 11.6 11.3IN-R5Q0930.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1.7 1.4 3.1 3.0 4.15.8IN-V9367 0.0 n.a. 0.0 n.a. 0.0 n.a. 2.0 n.a. 3.0 n.a. 3.1 n.a. 3.4 n.a.4.2n.a.Total other unknowns44.5 1.3 5.8 0.0 5.8 0.1 7.1 6.1 8.6 3.6 6.2 4.7 5.6 5.3 9.4 7.5Uncharacterized extractedresidues50.6 0.7Extracted residues0.6 0.7 5.1 3.8 5.1 2.6 4.2 4.7 7.7 6.8 7.4 8.1 9.8 9.1 7.8 7.0Unextracted residues 0.1 0.2 0.8 0.6 0.9 0.4 2.6 1.9 6.4 5.5 21.0 14.3 24.8 25.328.927.0Fulvic acidsn.p.0.1 0.1Humic acids9.7 10.4Humin10.7 14.8CO26n.p. n.p. 0.4 0.1 0.4 0.1 0.4 0.1 0.4 0.10.50.1 0.5 0.1 0.5 0.1Other volatile compounds ORBO tubes were not analyzed.Mass balance 100.6 102.6 105.6 103.3 103.5 102.3 104.3 104.3 102.6 103.4 102.8 102.2 104.4 104.2 104.3 103.4Data obtained from Table 7, p. 48; Table 10A, p. 53; Table 11A, p. 55; Table 12B, p. 57 of the study report.n.a. = Not applicable.n.p. = Not performed.1 Sampling site not described (pond, lake, river, ditch, rice paddy, etc.).2 PY = pyridine label, MD = pyrimidine label.3 Tentative identification based on LC/MS/MS molecular weight and fragmentation pattern (p. 36).4 Comprised of up to seventeen components, with no individual component >5% of applied in total system (Table 10A, p. 53; Table11A, p. 55; Figures 10A-11G, pp.81-88).5 Sediment extracts not analyzed by HPLC.6 Per label, all samples were connected to the same set of volatile traps.

### E. Transformation of Parent Compound: Transformation kinetics of the parent compound are

summarized in Figures 1a and 1b and Table 9 , with transformation product information

summarized in Table 10 . Rates of transformation of parent nicosulfuron and transformation product profiles were similar between the sand and silt loam sediments.

Using simple first order (SFO) regression analys is (ModelMaker 4.0), the study author calculated

nicosulfuron half-life and DT 90 

### values of 98.0 and 325.5 days, respectively, in the sand sediment (Tift) system and 90.2 and 299.7 days, respectively, in the silt loam sediment (Boonville) system (pp. 30-31, 36-37; Figure 13B, p. 100; Figure 14, p. 102) . Transformation kinetics of nicosulfuron in the systems were also evaluated using first order multi compartment (FOMC), hockey stick (HS) and double first order in parallel (DFOP) mode ls in accordance with FOCUS kinetics guidance (2006; Appendix 2, pp. 108-128).

Figure 1a. Transformation Kinetics of Nicosulf uron (Combined Labels) in Total Natural

Water:Sand Sediment 1, 2, 3 

# Nicosulfuron in Total Sand Sediment System

Days Nicosulfuron

0 0 3 3
7
7 14
14 31 31 60 60 80 80 102 102 97.1 95.2 101. 100. 96.9 99.3 89.7 98.0 80.5 91.6 62.5 66.0 55.8 62.6 45.5 53.9 0 20 40 60 80 100 0 20 40 60 80 100

TimeConcentration SFO

DFOP

IORE

-10 -5 0 5 10

-10 -5 0 5 10

-10 -5 0 5 10

0 20 40 60 80 100

DT 50 DT 90  2 C 0 Parameters

SFO 101 336 2.7 101 k
 0.00685

DFOP 106 326 1.8 96.2 f
 -0.0858

 k 0  0.52

 k 1  0.00732

IORE 98.5 217 2.7 101 N
 0.404

 k
 0.09 S C

S SFO Slow t 1 2

t R IORE 322

287

94.6

65.4 1 Sampling site (located in Georgia) was not described (pond, lake, river, ditch, rice paddy, etc.). 2 Data were obtained from Table 8A, p. 49; Table 9A, p. 51 of the study report, with kinetics calculated by reviewer

using R 8.5 (DER Attachment 2). 3 Kinetics models: Simple First Order (SFO); Double First Order in Parallel (DFOP), and Indeterminate Order Rate

Equation (IORE).Nicosulfuron (PC 129008) MRID 48790905

Page 15 of 28 

### Figure 1b. Transformation Kinetics of Nicosu lfuron (Combined Labels) in Total Natural Water:Silt Loam Sediment System 1, 2, 3 

# Nicosulfuron in Total Silt Loam Sediment System

Days Nicosulfuron

0 0 3 3
7
7 14
14 31 31 60 60 80 80 102 102 95.5 100. 98.7 103.

96.2 102.

92.2 92.6
75.7 82.8 59.8 69.6 52.6
57.7 45.6 49.7 0 20 40 60 80 100 0 20 40 60 80 100

TimeConcentration SFO

DFOP

IORE

-6 -4 -2 0 2 4 6

-6 -4 -2 0 2 4 6

-6 -4 -2 0 2 4 6

0 20 40 60 80 100

DT 50 DT 90  2 C 0 Parameters

SFO 92.3 307 1.8 102 k
 0.00751

DFOP 92.3 307 2 102 f
 0.188

 k 0  0.0075

 k 1  0.00751

IORE 92.2 294 1.9 101 N
 0.948

 k
 0.0094 S C

S SFO Slow t 1 2

t R IORE 213

179

92.4

88.5 1 Sampling site (located in Missouri) was not described (pond, lake, river, ditch, rice paddy, etc.). 2 Data were obtained from Table 10A, p. 53; Table 11A, p. 55 of the study report, with kinetics calculated by reviewer

using R 8.4; R 8.5 would not plot data (DER Attachment 2). 3 Kinetics models: Simple First Order (SFO); Double First Order in Parallel (DFOP), and Indeterminate Order Rate

Equation (IORE).Nicosulfuron (PC 129008) MRID 48790905

Page 16 of 28 

### Table 9. Transformation Kinetics of Ni cosulfuron in Total Aquatic Systems 1, 2

System 3 Observed

DT 50 (days) 4 Observed

DT 90 (days) 4 Calculated

Half-life

(days) Kinetics

Model 5 Model Parameters Model Statistics

Georgia natural

water:sand sediment system (20°C, water pH 7.6, sediment pH 7.6) ca . 101 >102 101 SFO C 0 = 101, k = 0.00685 S

c = 322,

S SFO = 287,

r 2 = --

98.5 IORE C 0 = 101, k = 0.09,

N = 0.404 t R IORE = 65.4,

r 2 = --

106 DFOP
[if applicable] C 0 = 96.2, k 0 = 0.52,

k 1 = 0.00732,

f = -0.0858 Slow t 1/2 = 94.6,

r 2 = --

Missouri natural

water:silt loam sediment system (20°C, water pH 7.9, sediment pH 7.8) ca . 95 >102 92.3 SFO C 0 = 102, k = 0.00751 S

c = 213,

S SFO = 179,

r 2 = --

92.2 IORE C 0 = 101, k = 0.0094,

N = 0.948 t R IORE = 88.5,

r 2 = --

92.3 DFOP
[if applicable] C 0 = 102, k 0 = 0.0075,

k 1 = 0.00751, f = 0.188 Slow t 1/2 = 92.4,

r 2 = -- 1 Calculated by the reviewer using R v. xxDeg_0.8.5 (sand sediment) and R v. xxDeg_0.8.4 (silt loam sediment) and

data obtained from Table 8A, p. 49; Table 9A, p. 51; Table 10A, p. 53; Table 11A, p. 55 of the study report (DER Attachment 2); -- = not calculated by R. 2 Calculated half-lives and model parameters for the best fit kinetics models, in accordance with the NAFTA kinetics guidance (USEPA, 2011), are in bold

. 3 Sampling site not described (pond, lake, river, ditch, rice paddy, etc.).

4 Based on mean nicosulfuron levels at each interval. 5 Kinetics models: Simple First Order (SFO); Double First Order in Parallel (DFOP), and Indeterminate Order Rate

Equation (IORE).



### One major transformation product and two minor products were de tected in both systems (pp. 35- 36; Figure 1, pp. 58-59):

 

### 2-[[(3,4-dihydro-6-methoxy-4-oxopyrimidin-2 -yl]aminocarbonyl]aminosulfonyl]-N,Ndimethyl-3-pyridinecarboxamide (IN-37740),

 

### 2-[[[[(1,6-dihydro-4-hydroxy-6- oxo-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,Ndiemethyl-3-pyridinecar boxamide (IN-R5Q09), and

 

### 2-(aminosulfonyl)-N,N-dimethyl-3 -pyridinecarboxamide (IN-V9367).

Identification of major produc t IN-37740 was confirmed against reference standard using LC/MS/MS (p. 36; Figures 12D-12F, pp. 92-94). Te ntative identification of minor product INR5Q09 was based on LC/MS/MS molecular weight and fragmentation pattern (p. 36; Figures 12G12J, pp. 95-98).Nicosulfuron (PC 129008) MRID 48790905

Page 17 of 28 

### Table 10. Transformation Products of Nicosu lfuron (Combined Labels) in Total Aquatic Systems

System 1 Transformation product(s) 2 Maximum

%AR

Observed Associated

Interval

(days) Final %AR

Observed Final Interval (days)

Georgia natural

water:sand sediment system (20°C, water pH 7.6, sediment pH 7.6) IN-37740 13.9 80 13.1 102

IN-R5Q09 6.6 102 6.6 102

IN-V9367 4.8 102 4.8 102

Missouri natural water:silt loam sediment system (20°C, water pH 7.9, sediment pH 7.8) IN-37740 13.0 80 11.6 102

IN-R5Q09 5.8 102 5.8 102

IN-V9367 4.2 102 4.2 102

Data obtained from Table 8A, p. 49; Table 9A, p. 51; Table 10A, p. 53; Table 11A, p. 55 of the study report. 1 Sampling site not described (pond, lake, river, ditch, rice paddy, etc.). 2 IN-37740 and IN-R5Q09 contained both pyridine and pyrimidine labels; IN-V9367 contained pyridine label.



### A transformation pathway was provided by the study au thor and is illustrated below (p. 37; Figure 15, p. 103). Nicosulfuron yields IN-37740 through demethylation of a pyrimidinyl methoxy group, with O-demethylation then yieldi ng IN-R5Q09 (tentative identificati on). Hydrolysis of the sulfonyl urea bridge of IN-37740 or IN-R5Q09 yields IN-V9367.

Figure 2. Anaerobic Aquatic Degradation Pathway of Nicosulfuron (DPX-V9360)Nicosulfuron (PC 129008) MRID 48790905

Page 18 of 28 

### III. Study Deficiencies and Reviewer's Comments

1. The study was conducted for an insufficient length of time. The study duration should normally not exceed 100 days, but should be conducted un til the decline of the test compound and the

formation and decline of transf ormation products are es tablished, or for no more than one year. For both systems, half-lives for nicosulfuron occu rred near the final sampling interval, the major product IN-37740 had only decreased from maximums of 13.0-13.9% of the applied at 80 days to 11.1-13.1% at study termination, and maximum levels of the products IN-R5Q09 (5.8-6.6%) and IN-V9367 (4.2-4.8%) occurred at study termination.

2. Unextracted [ 14 

### C]residues were detected at 10.4-20.2% and 14.3-28.9% of the applied in the sand and silt loam sediments, respectively, at 60-102 days, but only the 102-day samples were characterized through orga nic matter fractionation.

3. The study author failed to demonstrate that pare nt nicosulfuron was stab le in water layer and sediment extract samples prior to analysis. Water layer and sediment extracts were reported as "typically" analyzed within 24 hours and 1 wee k, respectively, from sampling (p. 24). The study author reported that water layer and se diment extracts were "stored in a freezer ( ca

. 20oC)", which appears to be in error (p. 24) . In the Materials a nd Methods section 3.5.4 Sample Storage Conditions (p. 24), the study author reported wa ter layer samples were re-analyzed after 70 days of storage, then in th e Results and Discussion section 4.8 Storage Stability (p. 37) reported re-analysis of sediment extracts conduct ed up to 70 days after initial HPLC analysis found "the profiles remaining approximately the same"; additional details and supporting quantitative results and chromatograms were not provided. Given that the majority of the

residues resided in the water colu mn, the reported re-analysis of sediment extracts after storage most likely refers to re-analy sis of water layer samples.

Re-analysis of the pyridine-2- and pyrimidine-2-l abel dosing solutions after 119 days of storage found radiochemical purities of 95.5% and 98.5%, respectively (p. 37).

4. The study author failed to specify that the nominal test application rate used in this study was equivalent to the maximum field use rate, which impacts maximum concentrations of nicosulfuron transformation products that may be detected.

If the test application rate significantly exceed s the maximum field use rate, it must be shown that an exaggerated applicati on rate does not adversely affect the microbial activity of the water:sediment system, and thereby influence the rate and route of tran sformation of the test compound and the formation and decline of transformation products. OCSPP guidelines specify that data from exaggerated dose studies shoul d only be used for degradate identification

purposes.

5. All samples from a given treatment (sediment type, label) were connected in series to the same set of volatile traps (p. 21; Figure 2, p. 61). The reported concentration of CO 2 

### was adjusted based on the number of samples in the series at th e time of sampling (p. 30). It is preferred that sample vessels be connected to i ndividual volatile traps so that more precise material balances for each sample can be calculated.Nicosulfuron (PC 129008) MRID 48790905

Page 19 of 28 

### 6. Collection and storage of the sediments and associ ated waters were not adequately described. a) The pesticide use histories for the source si tes for the test sediments and associated waters were not reported. The sediment and water were not analyzed for pesticides to establish that they were not contaminated prior to treatment. b) The sampling sites were not described (pond, lake, river, ditch, rice paddy, etc.). c) Collection procedures (sampling met hods, depths) were not described. d) Sediments and associated waters appear to have been stored separately; sediments reported as stored at ca . 4oC in darkness, but storage of waters was not reported. The length of storage prior to pr eparation of water:sediment systems for pretreatment acclimation was reported as less than one mont h, but collection dates were not reported. Current OCSPP guidelines specify if storage is necessary, sediment and water should be sieved and stored together, water-logged (6- 10 cm water layer), in the dark, at 4 ± 2°C

for a maximum of 4 weeks.

7. For the Boonville test systems, the water:sediment volume ratio used, taking into account water associated with the sediment, was 5.5:1 (422 g total water:76.1 g dry wt. sediment). Current OCSPP guidelines recommend a minimum amount of 50 g of sediment (dry wt. basis) per incubation vessel is utilized, a sediment layer of 2.5 ± 0.5 cm, and a water:sediment volume

ratio between 3:1 and 4:1.

8. In section 3.7.1.1 Material Balance of the study report (pp. 29-30) , ethylene glycol traps are mentioned, and in Figure 2 (p. 61) the schematic of the flow-through appara tus indicates a liquid organic volatiles trap ("5") was used. ORBO-32 t ubes were used in lieu of ethylene glycol (pp. 21-22).

9. Page 43 of the study report was missing; page 42 was duplicated.

10. In Tables 8A-11B (pp. 49-56), both the Tift an d Boonville systems are described as "(Loam)", when the systems are characterized as sand and silt loam sediments, respectively (Table 1, p. 40).

IV. References

1. U.S. Environmental Protection Agency. 2008. Fa te, Transport and Transformation Test - Guidelines, OPPTS 835.4400, Anaerobic Aquatic Meta bolism. Office of Prevention, Pesticides and Toxic Substances, Washi ngton, DC. EPA 712-C-08-019.

2. U.S. Environmental Protection Agency. 2011. Guidance for Evaluating and Calculating Degradation Kinetics in Envir onmental Media. (Interim draf t document dated Dec. 21, 2011.)Nicosulfuron (PC 129008) MRID 48790905Page 20 of 28DER ATTACHMENT 1. Nicosulfuron and Its Environmental Transformation Products.ACode Name/SynonymChemical NameChemical StructureStudy TypeMRIDMaximum%AR (day)Final %AR(study length)PARENTNicosulfuron(DPX-V9360)IUPAC:2-[(4,6-Dimethoxypyrimidin-2-ylcarbamoyl)sulfamoyl]-N,NdimethylnicotinamideCAS:2-[[[[(4,6-Dimethoxy-2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamideCAS No.:111991-09-4Formula:C15H18N6O6SMW:410.411 g/molSMILES:c1(c(nccc1)S(=O)(=O)NC(=O)Nc2nc(cc(n2)OC)OC)C(=O)N(C)CSOOOO CH3O CH3NNNHNHONCH3CH3N835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:101.0%(3 d)53.9%(102 d)Natural watersilt loamsediment:102.6%(3 d)49.7%(102 d)MAJOR (>10%) TRANSFORMATION PRODUCTSIN-37740CAS:2-[[(3,4-Dihydro-6-methoxy4-oxopyrimidin-2-yl]aminocarbonyl]aminosulfonyl]-N,N-dimethyl-3-pyridinecarboxamideFormula:C14H16N6O6SMW:396.38 g/molSMILES:c1(c(nccc1)S(=O)(=O)NC(N/C2=N/C(=C\C(N2)=O)OC)=O)C(N(C)C)=O835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:13.9%(80 d)113.1%(102 d)1Natural watersilt loamsediment:13.0%(80 d)111.6%(102 d)1UnextractedresiduesNA NA835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:20.2%(102 d)20.2%(102 d)Nicosulfuron (PC 129008) MRID 48790905Page 21 of 28Code Name/SynonymChemical NameChemical StructureStudy TypeMRIDMaximum%AR (day)Final %AR(study length)Natural watersilt loamsediment:28.9%(102 d)28.9%(102 d)MINOR (<10%) TRANSFORMATION PRODUCTSIN-R5Q09CAS:2-[[[[(l,6-Dihydro-4-hydroxy6-oxo2-pyrimidinyl)amino]carbonyl]amino]sulfonyl]-N-N-dimethyl-3 -pyridinecarboxamide)Formula:C13H14N6O6SMW:382 g/molSMILES:CN(C)C(=O)c1cccnc1S(=O)(=O)NC(=O)NC2=NC(=O)CC(=N2)ONHNOONNHONHSOONCH3CH3O835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:6.6% (102 d)16.6% (102 d)1Natural watersilt loamsediment:5.8% (102 d)15.8% (102 d)1IN-V9367CAS:2-(Aminosulfonyl)-N,Ndimethyl-3-pyridinecarboxamideCAS No.:112006-75-4Formula:C8H11N3O3SMW:229.259 g/molSMILES:c1(cccnc1S(=O)(=O)N)C(=O)N(C)C835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:4.8% (102 d)14.8% (102 d)1Natural watersilt loamsediment:4.2% (102 d)14.2% (102 d)1Carbon dioxideIUPAC:Carbon dioxideFormula:CO2MW:44 g/molSMILES:C(=O)=O835.4400Anaerobicaquaticmetabolism48790905Natural watersand sediment:4.6% (102 d)4.6% (102 d)Natural watersilt loamsediment:0.5% (60, 80,102 d)0.5% (102 d)Nicosulfuron (PC 129008) MRID 48790905Page 22 of 28Code Name/SynonymChemical NameChemical StructureStudy TypeMRIDMaximum%AR (day)Final %AR(study length)REFERENCE COMPOUNDS NOT IDENTIFIEDIN-64554CAS:Isothiaxolo[5,4-b]pyridin3(2H)-one,1,1-dioxideCAS No.:138417-40-0Formula:C6H4N2O3SMW:184.17 g/molSMILES:c12cccnc1S(NC2=O)(=O)=O835.4400Anaerobicaquaticmetabolism48790905 NA NAIN-J0290CAS:4,6-Dimethoxy-2-pyrimidinamineCAS No.:36315-01-2Formula:C6H9N3O2MW:155.15 g/molSMILES:Nc1nc(cc(n1)OC)OC835.4400Anaerobicaquaticmetabolism48790905 NA NAIN-GDC42CAS:2-[[[[(Aminocarbonyl)amino]carbonyl]amino]sulfonyl]-N,N-dimethyl-3-pyridinecarboxamideFormula:C10H13N5O5SMW:315.309 g/molSMILES:c1(ncccc1C(=O)N(C)C)S(NC(NC(N)=O)=O)(=O)=O835.4400Anaerobicaquaticmetabolism48790905 NANANicosulfuron (PC 129008) MRID 48790905Page 23 of 28Code Name/SynonymChemical NameChemical StructureStudy TypeMRIDMaximum%AR (day)Final %AR(study length)IN-77799CAS:2-[(Aminocarbonyl)[4-methoxy-6-(methyldioxy)-2-pyrimidinyl]amino]-N,N-dimethyl3-pyridinecarboxamideFormula:C15H18N6O4MW:346.34 g/molSMILES:NC(N(c1nc(cc(n1)OC)OC)c2ncccc2C(N(C)C)=O)=O835.4400Anaerobicaquaticmetabolism48790905 NA NAIN-HYY21CAS:2-[[[[(Aminoiminomethyl)amino]carbonyl]amino]sulfonyl]-N,Ndimethyl-3-pyridinecarboxamideFormula:C10H14N6O4SMW:314.33 g/molSMILES:c1(c(nccc1)S(=O)(=O)NC(NC(=N)N)=O)C(N(C)C)=O835.4400Anaerobicaquaticmetabolism48790905 NA NAAAR means “applied radioactivity”. MW means “molecular weight”. NA means "not applicable".1IN-37740 and IN-R5Q09 contained both pyridine and pyrimidine labels; IN-V9367 contained pyridine label.Nicosulfuron (PC 129008) MRID 48790905Page 24 of 28Attachment 2: Statistics Spreadsheets and GraphsChemical: NicosulfuronMRID: 48790905PC: 129008Guideline: 835.4400pE + pH: Georgia Sand Sediment (Tift) System - TreatedDays Water layer SedimentPosttreatmentMeasuredEh Measured pH pE pE + pHpE + pH <12?MeasuredEh Measured pH pE pE + pHpE + pH <12?0 -189.8 7.905 -3.2 4.7 Yes-223.4 7.195 -3.8 3.4 Yes0 -176.3 7.790 -3.0 4.8 Yes-220.3 7.140 -3.7 3.4 Yes3 -139.1 8.607 -2.3 6.3 Yes-133.2 7.195 -2.3 4.9 Yes3 -62.5 7.784 -1.1 6.7 Yes-204.7 7.099 -3.5 3.6 Yes7 -127.8 7.582 -2.2 5.4 Yes-207.2 7.087 -3.5 3.6 Yes7 -88.3 7.430 -1.5 5.9 Yes-211.8 7.088 -3.6 3.5 Yes14 -130.1 7.484 -2.2 5.3 Yes -219.9 7.088 -3.7 3.4 Yes14 -72.0 7.422 -1.2 6.2 Yes -203.8 7.084 -3.4 3.6 Yes31 -153.0 7.704 -2.6 5.1 Yes -219.4 7.119 -3.7 3.4 Yes31 -36.2 7.596 -0.6 7.0 Yes -193.3 7.130 -3.3 3.9 Yes60 -225.1 8.264 -3.8 4.5 Yes -272.2 7.334 -4.6 2.7 Yes60 -215.3 8.330 -3.6 4.7 Yes -253.0 7.314 -4.3 3.0 Yes80 -147.5 8.262 -2.5 5.8 Yes -224.6 7.311 -3.8 3.5 Yes80 -200.7 8.494 -3.4 5.1 Yes -238.4 7.356 -4.0 3.3 Yes102 -219.1 8.478 -3.7 4.8 Yes -231.6 7.465 -3.9 3.6 Yes102 -122.7 8.664 -2.1 6.6 Yes -196.1 7.534 -3.3 4.2 YesData from Table 4A, p. 45 of the study report.Days Posttreatment, Measured Eh and Measured pH are inputfields. pE, pE + pH and pE + pH < 12? are output fields.Nicosulfuron (PC 129008) MRID 48790905Page 25 of 28Chemical: NicosulfuronMRID: 48790905PC: 129008Guideline: 835.4400pE + pH: Missouri Silt Loam Sediment (Boonville) System - TreatedDays Water layer SedimentPosttreatmentMeasuredEh Measured pH pE pE + pHpE + pH <12?MeasuredEh Measured pH pE pE + pHpE + pH <12?0 -161.0 7.415 -2.7 4.7 Yes-246.9 7.229 -4.2 3.1 Yes0 -160.9 7.680 -2.7 5.0 Yes-236.3 7.230 -4.0 3.2 Yes3 -204.1 7.630 -3.4 4.2 Yes-233.8 7.221 -3.9 3.3 Yes3 -165.1 7.631 -2.8 4.8 Yes-205.8 7.341 -3.5 3.9 Yes7 -156.0 7.480 -2.6 4.8 Yes-230.9 7.229 -3.9 3.3 Yes7 -146.6 7.477 -2.5 5.0 Yes-236.1 7.222 -4.0 3.2 Yes14 -154.3 7.294 -2.6 4.7 Yes -239.7 7.194 -4.0 3.1 Yes14 -148.4 7.554 -2.5 5.0 Yes -242.8 7.191 -4.1 3.1 Yes31 -199.4 7.348 -3.4 4.0 Yes -236.6 7.134 -4.0 3.1 Yes31 -227.9 7.427 -3.8 3.6 Yes -238.5 7.187 -4.0 3.2 Yes60 -195.5 7.757 -3.3 4.5 Yes -243.4 7.203 -4.1 3.1 Yes60 -210.2 8.106 -3.6 4.6 Yes -254.1 7.225 -4.3 2.9 Yes80 -212.5 7.957 -3.6 4.4 Yes -221.5 7.248 -3.7 3.5 Yes80 -165.6 8.061 -2.8 5.3 Yes -189.9 7.212 -3.2 4.0 Yes102 -240.6 8.153 -4.1 4.1 Yes -239.0 7.336 -4.0 3.3 Yes102 -245.6 8.248 -4.1 4.1 Yes -249.5 7.332 -4.2 3.1 YesData from Table 5A, p. 46 of the study report.Days Posttreatment, Measured Eh and Measured pH are inputfields. pE, pE + pH and pE + pH < 12? are output fields.Nicosulfuron (PC 129008) MRID 48790905Page 26 of 28Attachment 3: CalculationsCalculations were performed by the reviewer using R software, and the following equations.Single First-Order (SFO) Model(eq. 1)where,Ct= concentration at time t (%)C0= initial concentration (%)e = Euler’s number (-)k = SFO rate constant of decline (d-1)t = time (d)The SFO equation is solved withR kinetics software by adjustingC0andkto minimize the objective function (SSFO) shown in equation 9.DT50= natural log (2)/k (eq. 2)DT90= ln (10)/k (eq. 3)Indeterminate Order RateEquation (IORE) Model(eq. 4)where,N = order of decline rate (-)kIORE= IORE rate constant of decline (d-1)This equation is solved with R kineticssoftware by adjusting C0, kIORE, and N tominimize the objective function for IORE (SIORE) (Seeequation 9). Half-lives for the IORE model are calculated using equation 5, whichrepresents a first-order half-life that passes through theDT90of the IORE model. (Traditional DT50and DT90values for the IORE model can becalculated using equations 6 and 7.)Nicosulfuron (PC 129008) MRID 48790905Page 27 of 28(eq. 5)DT50=1)-k(NC-/2)(CN)-(10N)-(10(eq. 6)DT90=1)-k(NC-/10)(CN)-(10N)-(10(eq. 7)Double First-Order in Parallel (DFOP) Model(eq. 8)where,g = the fraction of C0applied to compartment 1 (-)k1= rate constant for compartment 1 (d-1)k2= rate constant for compartment 2 (d-1)IfC0x gis set equal toaandC0(1-g)is set equal toc, then the equation can be solvedwith R kinetics software fora,c,k1, andk2byminimizing the objective function (SDFOP) as described in equation 9.DT50and DT90values can be calculated using equations 2 and 3, with k1or k2in place of k.Objective Function: SFO, IORE, and DFOP aresolved by minimizing the objective function (SSFO, SIORE, or SDFOP).(eq. 9)where,SSFO, SIORE, or SDFOP= objective function of kinetics model fit (%2)n = number of data points (-)Nicosulfuron (PC 129008) MRID 48790905Page 28 of 28Cmodel,t= modelled value at time corresponding to Cd,t(%)Cd,t= experimental concentration at time t (%)Critical Value to Determine WhetherSFO is an Adequate Kinetics ModelIf SSFOis less than SC, the SFO model is adequateto describe kinetics. If not, the faster of tIOREor the DFOP DT50for compartment 2 shouldbe used.(eq. 10)where,Sc= 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 withαlevel of confidence and degrees of freedom p and n-p