UNITED STATES ENVIRONMENTAL PROTECTlON AGENCY 

WASHINGTON D.C., 20460 

Date: 

Chemical: 

PC Code: 

Barcode: 

OFFICE OF CHEMICAL SAFETY 

AND POLLFTION PREVENTION 

November 25, 2013 

Flazasulfuron 

119011 

DP 408779 

MEMORANDUM 

SUBJECT: Review of Batch Equilibrium Study on Flazasulfuron and Degradates on Two 

Alkaline Soils 

FROM: Andrew Shelby, Physical Scientist;- - ....._....-......- - //?,,,. - ------~ii-z.S--I~ 

Mark Corbin, Branch Chief _ . ~G_A Environmental Risk Branch 6 \ \.1') .. \') 

Environmental Fate and Effects Division (7507P 

TO: K.hue Nguyen, Risk Manager Reviewer 

Pesticide Re-Evaluation Division (7508P) 

The Environmental Fate and Effects Division (EFED) has completed its review of a study 

[MRIDs: 49030002] submitted on environmental fate of flazasulfuron. The study is classified as 

acceptable. findings of the review are presented in the following table. 

Enviror•irnental fate data classificat~ons for etbaboxam 

MRID Study 

Classification 1 

Remarks 

49030002 Acceptable 

1

0PPIN Classifications: 

Acceptable/Guideline; Acceptable/Non-Guideline; Cited; Confirmatory; Decision Deferred; 

Extraneous submission; In Review; No Decision; Partially Acceptable; Supplemental: 

Unacceptable/Guideline; Unacceptable/Non-Guideline; Upgradeable. 

I 
Test Material: Flazasulfuron 

MRID 49030002 

Title: Shepler, K. 2012. Adsorption/desorption of [

14

C)flazasulfuron, DTPU, 

DTPP, ADMP, and TPSA on one soil and a sediment. 

EPA PC Code: 119011 

OCSPP Guideline: 835.1230 

For CDM Smith 

Primary Reviewer: Kindra Bozicevich Signature: 

Date: 11/19/13 

Secondary Reviewer: Joan Harlin Signature: 

Date: 11/19/13 

QC/QA Manager: Joan Gaidos Signature: 

Date: 11/19/13 
Flazasulfuron (PC 119011) MRID 49030002 

Adsorption and desorption of Flazasulfuron, DTPU, DTPP, ADMP, and TPSA on 

one soil and a sediment. 

Report: 

Document No.: 

Guideline: 

Statements: 

Classification: 

PC Code: 

Reviewer: 

MRID 49030002. Shepler, K. 2012. Adsorption/desorption of 

[

14C]flazasulfuron, DTPU, DTPP, ADMP, and TPSA on one soil and a 

sediment. Unpublished study performed by PTRL West, Hercules, 

California; sponsored and submitted by Ishihara Sangyo Kaisha, Ltd., Osaka, 

Japan. Report Number 2293 W-1. Project Number 2293 W. Experimental 

initiation June 21, 2012 and completion September 6, 2012 (p. 13). Study 

completion date December 26, 2012. 

MRID 49030002 

OCSPP 835.1230 

The study was conducted in accordance with USEP A 40 CFR Part 160 (p. 

3). Signed and dated Data Confidentiality, GLP, and Quality Assurance 

statements were provided (pp. 2-4). A Certification of Authenticity was not 

provided. 

This study is acceptable. The study was conducted using the parent 

compound flazasufuron as well as four transformation products. The study 

was conducted using only two types of soils. The parent compound was 

found to be highly unstable in solution with significant degradation. 

119011 

Andrew Shelby 

EPA 

Signature·// 

Date: 11/~} .A-..~-A . -...-... --

· ~ ~ 

Executive Summary 

In a batch equilibrium study, two U.S. soils (pH range 8.2-8.5) were used to measure 

sorption coefficients of [

14

C]-labeled flazasulfuron and its soil metabolites DTPU, DTPP, 

ADMP, and TPSA in darkness at 25°C. For the parent compound flazasulfuron, 

determined Freundlich Adsorption Coefficient (KF) values ranged from 0.16 to 0.23 L/kg 

(mean KF = 0.19 L/kg); respective Krnc values ranged from 20 to 77 L/kg (mean KFoc = 

48.2 L/kg). 1 Freundlich Desorption Coefficients (KF-des; range 0.89 to 0.93 L/kg, mean KF 

= 0.91 L/kg) were higher than those obtained for the initial sorption measurement, 

indicating a degree of irreversible sorption. Percent adsorption and percent desorption, as 

percent of the adsorbed, were not determined. Freundlich exponents corresponding to KF 

values ranged from 0.78 to 0.88 across all test soils. 

1 Sorption is a generic term that applies to absorption, adsorption, and desorption processes. Adsorption 

refers to sorption onto a two-dimensional surface; absorption refers to sorption into a three dimensional 

matrix. Both types of sorption occur in soils and sediments. Desorption refers to a sorbate becoming 

desorbed from a sorbent. Desorption distribution coefficients are measured by removing solution from a 

sorption experiment and adding fresh solution, so that all material measured in solution will be the 

desorbed material. The guideline uses the term adsorption in place of sorption and refers to the initial 

measurement of sorption. 

2 of29 
' 

.... -. 

" 

Flazasulfuron (PC I 19011) MRJD 49030002 

Table 3 summarizes the adsorption coefficients measured in the study. Table 4 

summarizes the desorption coefficients measured in the study. 

Mass balances ranged from 96.2-111 .6% of the applied for the soils treated with 

[

14C]flazasulfuron and 87.5-104.0% for soils treated with [14C]-labeled TPSA, DTPU, 

DTPP, and ADMP. HPLC analysis of test soils treated at the highest test concentration (5 

mg/L) showed that [

14C]flazasulfuron was unstable in both test soils. TPSA, DTPU, 

DTPP, and ADMP were stable in both test soils. 

Coefficients of variation (CV) ranged from 0.02 to 1.1and0.2 to 0.8, respectively, across 

all [

14C]-treated soils for adsorption KF and KFoc, and 0.03 to 0.7 and 0. 1 to 0.6, 

respectively, across all [

14C]-treated soils for desorption KF and K Foc· 

Results Synopsis: 

3 of29 
Flazasulfuron (PC 119011) MRlD 49030002 

T a e bl 1 . S ummary o f Ad sorp f aou /D esorp f aou R esu It s A 

Soil/ Regressed Kd Regressed KF 1/n for KFoc 

Sediment, (L/kg-soil) Range of Koc(L/kg- ( (L/kg-so i1>· 1'") adsorption (L/k~-oc>· Ceq 

%0C Kd(L/kg- OC) I") Range 

pH Value ± p-value soil) Value ± I 

Value ± Value± (mg/L) 

SE 

,.2 Value ± SE SE r~ p-value SE SE 

Flazasulfuron 

Adsorption 

Golden Lake 

Sand 0.20 ± 0.0 0.985 l.5£-09 0.17-0.39 67 ± 3 0.23 ± 1.0 0.996 6.2 ±E-11 0.88 ± 0.0 77 ± 344 0.0354-

(0.3% oc 3.8065 

pH 8.5) 

WY Clay 0.0379- (0.8%0C, 0.10 ± 0.0 0.834 8.7E-05 0.07-0.28 12 ± 2 0.16 ± l.I 0.962 4.4E-08 0.78 ± 0.l 20 ± 137 4. 1293 pH 8.3) 

Desorption 

Golden Lake 

Sand 0.92 ± 0.1 0.944 6.3E-07 0.71-1.52 308 ± 25 0.89 ± 1.1 0.987 0.364 0.89 ± 0.0 298 ± 375 0.0042-

(0.3%0C 0.3564 

pH 8.5) 

WY Clay 0.0028- (0.8%0C, 1.17 ± 0.2 0.775 0.0004 0.64-3.14 146 ± 26 0.93 ± l.4 0.901 0.834 0.77 ± 0.I 116 ± 176 0.1805 pH 8.3) 

4 of29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 1 (coot). Summary of Adsorption/Desorption Results A 

Soil/ Regressed Kd Regressed KF l/n for Kroc I 

Sediment, (L/kg-soil) Range of Koc (U kg- ((Ukg-soi1>·

110) adsorption (L k~-oc>- Ceq 

%0C K.i(Ukg- OC) I") Range 

pH Value ± p-value soil) Value± I Value ± Value ± (mg/L) 

SE rz Value ± SE SE rz p-value SE SE 

TPSA 

Adsorption 

Golden Lake 

Sand 0.10 ± 0.0 0.995 7.5E-12 0.09-0. 12 35 ± 0.8 0.11 ± 1.0 0.998 2.0E-13 0.97 ± 0.0 35 ± 342 0.0382-

(0.3%0C 4.5430 

pH 8.5) 

WY Clay 0.0380- (0.8%0C, 0.10 ± 0.0 0.995 7.2E- 12 0.09-0.13 12 ± 0.3 0.11 ± 1.0 0.998 5.IE-13 0.96 ± 0.0 14 ± 128 4.5557 pH 8.3) 

Desorption 

Golden Lake 

Sand I. I ± 0.1 0.963 9.9E-08 0.95-1.93 358 ± 24 I. I ± 1.2 0.983 0.599 0.98 ± 0.0 367 ± 398 0.0018-

(0.3% oc 0.2133 

pH 8.5) 

WY Clay 1.54- 0.0004- (0.8% oc, 3.4 ± 0.6 0.820 0.0008 18.86 430 ± 76 2. 1 ± 2.0 0.854 0.307 0.83 ± 0. 1 266 ± 246 0.0829 pH 8.3 ) 

5 of 29 
Flazasu lfuron (PC 119011) MRID 49030002 

A Table 1 (cont). Summary of Adsorption/Desorption Results 

Soil/ Regressed Kd Regressed KF l/o for Krnc 

Sediment, (L/kg-soil) Range of Koc (L/kg- ( ( L/kg-soil>· 11") adsorption (LJkg-oc>· Ceq 

%0C Kd(L/kg- OC) "") Range 

pH Value± p-value soil) Value± I Value ± Value ± (mg/L) 

SE 

r2 Value± SE SE ri p-value SE SE 

DTPU 

Adsorption 

Golden Lake 

Sand 0.42 ± 0.0 0.989 4.4E-10 0.38-0.76 140 ± 5 0.50 ± 1.0 0.998 l. lE-09 0.87 ± 0.0 166 ± 341 0.0294-

(0.3% oc 3.6445 

pH 8.5) 

WY Clay 0.0299- (0.8%0C, 0.63 ± 0.0 0.997 5.2E-1 3 0.61-0.75 79 ± l 0.67 ± 1.0 0.999 4.2E-08 0.97 ± 0.0 83 ± 128 3.14 74 

pH.8.3) 

Desorntion 

Golden Lake 

Sand l.9 ± 0.1 0.991 l.4E- 10 1.74-3.62 631 ± 20 1.7±1.1 0.997 6.4E-06 0.85 ± 0.0 562±351 0.0047-

. (0.3% oc 0.5084 

pH 8.5) 

WY Clay 0.0034- (0.8%0C, 4.5 ± 0.2 0.977 l.2E-08 4.18-7.45 557 ± 29 5.0 ± 1.1 0.986 2.7E-06 0.98 ± 0.0 619 ± 144 0.3692 pH 8.3) 

6 of29 
Flazasulfuron (PC 11901 1) MRID 49030002 

Table 1 (cont). Summary of Adsorption/Desorption Results 

A 

Soil/ Regressed Kd Regressed KF l/n for KFoc 

Sediment, (L/kg-soil) Range of Koc (L/kg- ((L/kg-soii>"11

") adsorption (L/k~-OC}- Ceq 

%0C l<o(L/kg- OC) I") Range 

pH Value ± p-value soil) Value± I Value ± Value± (mg/L) 

SE rz Value± SE SE rz p-value SE SE 

DTPP 

Adsorption 

Golden Lake 

Sand 5.0 ± 0.2 0.988 5.9E-IO 4.02- 1679 ± 62 5.9 ± l.O 0.994 l.3E-10 0.81 :I: 0.0 1980 ± 348 0.0206-

(0.3% oc 13.31 3.3879 

pH 8.5) 

WY Clay 8.41- 0.0 106- (0.8% oc, 9. 1± 0.6 0.968 5.lE-08 35.31 1140 ± 69 11.8 ± l.l 0.973 7.4E-09 0.74 ± 0.0 1473 ± 138 2.73 15 pH 8.3 ) 

Desorption 

Golden Lake 

Sand 41.7 ± 0.9 0.995 7.I E-12 39.91- 13898 :I: 3 12 37.7 ± 1.0 0.999 7.3E-l4 0.91 ± 0.0 12557 ± 0.0034-

(0.3% 0 C 63.50 345 0.3412 

pH 8.5) 

WY Clay 85.81- 0.002- (0.8% 0C, 92.7 ± 4.5 0.979 7.0E-09 177.25 I 1583 ± 562 77.6 ± I.I 0.992 I.OE-IO 0.88 ± 0.0 9703 ± 139 0.2481 pH 8.3) 

7 of29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 1 (cont). Summary of Adsorption/Desorption Results A 

Soil/ Regressed Kd Regressed Kr l/n for KFoc 

Sediment, (L/kg-soil) Range of Koc (L/kg- ((L/kg-soi1>-1

'") adsorption (L/kg-oc>- Ceq 

%0C Kd(L/kg- OC) l/n) Range 

pH Value± p-value soil) Value± 

I 

Value± Value± (mg/L) 

SE r2 Value± SE SE rz p-value SE SE 

ADMP 

Adsorption 

Golden Lake 

Sand 0.39 ± 0.0 0.935 l.2E-06 0.30-1.18 130 ± 11 0.55 ± 1.1 0.983 2.6E-05 0.79 ± 0.0 184 ± 357 0.0225-

(0.3%0C 3.8756 

pH 8.5) 

WY Clay 2.86- 0.0064- (0.8%0C, 3.2 ±0.3 0.919 3.3E-06 26.56 400 ± 40 5.0 ± 1.1 0.983 2.8E-08 0.64 ± 0.0 628 ± 135 2.9165 pH 8.3) 

Desorption 

Golden Lake 

Sand 5.3 ± 0.5 0.943 3.0E-06 4.89- 1764 ± 153 4.5 ± 1.3 0.967 0.0003 0.87 ± O.l 1497 ± 419 0.002-

(0.3%0C 12.52 0.2529 

pH 8.5) 

WY Clay 12.93- 0.0022- (0.8%0C, 14.8±1.5 0.918 3.5E-06 74.73 1845 ± 184 13.l ± 1.3 0.927 4.3E-06 0.67 ± 0.1 1632 ± 158 0.4941 pH 8.3) 

Abbrev1at10ns: SE = standard error of regression. 

A Data were obtained from Appendix G, pp. 203 -204; Appendix H, pp. 212-213; Appendix I, pp. 221-222; Appendix J, pp. 232-233; and Appendix K, pp. 241-

242 of the study report. Data and results are in the attached Excel workbook. See Attachment 3 for equations used for calculations. 

8 of29 
Flazasu I furon CPC 11901 I) MRID 49030002 

I. Material and Methods 

A. Materials 

1. Test Material: [

14C]-labeled flazasulfuron (SL-160; p. 18; Figure 1, p. 75; 

Figure 2, p. 76; Appendix B, p. 140) 

Batch/Lot number: CP-1385-2 

Specific radioactivity: 4.18 MBq/mg 

Radiochemical purity: >93% 

Chemical purity: Not reported 

Solubility in water: Not reported 

Structure 

N ft ~ N~· o- cH, $-N N-< ~ II I I 14- o H H 

0- Cll, 

F 

(14C]-labeled TPSA (p. 18; Figure 1, p. 75; Figure 2, p. 77; 

Appendix B, p. 142) · 

Batch/Lot number: CP-3082 

Specific radioactivity: 9.15 MBq/mg 

Radiochemical purity: >99% 

Chemical purity: Not reported 

Solubility in water: Not reported 

Structure: 

~: 

~ .. N ~ o H ll"w ........ o I 

H 

[

14C]-labeled DTPU (p. 18; Figure 1, p. 75; Figure 2, p. 78; 

Appendix B, p. 146) 

Batch/Lot number: CP-3083 

Specific radioactivity: 5.63 MBq/mg 

Radiochemical purity: >98% 

Chemical purity: Not reported 

Solubility in water: Not reported 

Structure: 

9of29 
Flazasulfuron (P~ 119011) MRID 49030002 

(

14C]-Iabeled DTPP (p. 18; Figure 1, p. 75; Figure 2, p. 79; 

Appendix B, p. 144) 

Batch/Lot number: CP-3084 

Specific radioactivity: 6.42 MBq/mg 

Radiochemical purity: >99% 

Chemical purity: Not reported 

Solubility in water: Not reported 

Structure: 

[Pyrimidine-5- 14C)-labeled ADMP (p. 18; Figure 1, p. 75; Figure 

2, p. 80; Appendix B, p. 148) 

Batch/Lot number: CP-3085 

Specific radioactivity: 10.4 MBq/mg 

Radiochemical purity: >99% 

Chemical purity: Not reported 

Solubility in water: Not reported 

Structure: · 

O-CH3 

"'-1---1---( H N=< O-CH3 

10of29 
Flazasulfuron (PC 119011) MRID 49030002 

2. Ref ere nee 

Compounds: Flazasulfuron (SL-160; p. 18; Appendix B, p. 141) 

Batch/Lot number: Y-920205 

Purity: l 00% 

ADMP (p. 18; Appendix.B,p. 149) 

Batch/Lot number: Y-Ba.79 

Purity: 100% 

DTPU (p. 18; Appendix B, p. 147) 

Batch/Lot number: 0205 

Purity: 98.5% 

DTPP (p. 18; Appendix B, p. 145) 

Batch/Lot number: 0205 

Purity: 98.3% 

TPSA (p. 18; Appendix B, p. 143) 

Batch/Lot number: 0205 

Purity: 100% 

3. Soils/Sediment: The study was conducted using one sediment and one soil (p. 21; 

Table II, p. 45). Pesticides use history at the collection sites was not reported. The 

soils were sieved (2 mm) and stored in plastic bags. A summary of the physical and 

chemical properties of the soils is provided in Table 2 using USDA Soil Taxonomy. 

T bl e 2 . D a escnption o rs Ol ·11s e d' 1ment 

Soil Name Golden Lake Sand WY Clay 

Origin Steele, North Dakota Fremont Co., Wyoming 

USDA Textural Class Sand Clay 

%Sand 95 25 

%Silt 2 28 

%Clav 3 47 

%0C 0.3 0.8 

CEC (meq/100 g) 8.0 28.6 

pH in water (1: 1) 8.5 8.3 

oH (0.0 lM CaCh) 8.2 NR 

% moisture (1/3 bar) 4.7 28.8 

Soil Taxonomy NR NR 

CaC03 equivalence NR NR 

Data were obtained from Table II, p. 45 and Appendix C, pp. 150-151 of the study report. 

NR = not reported. 

B. Study design 

1. Experimental conditions: Preliminary tests were conducted to examine the 

appropriate soil:solution ratio (Tier I) and equilibration times to be used in the 

definitive test (Tier 2; pp. 22-26). 

11 of29 
Flazasulfuron (PC 1190 11) MRID 49030002 

For Tier 1 tests, aliquots of Golden Lake sand and WY clay soils were prepared in 

O.OlM CaCh solution at soil:solution ratios of 1: 1, 1 :5, and 1 :25 (w:v; pp. 22-23). 

The solutions were then dosed with [14

C]-labeled :flazasulfuron, TPSA, DTPU, 

DTPP, and ADMP at ca. 5 mg/L. Soil-less controls and blank samples were also 

prepared. The flazasulfuron test .was also conducted at a soil:sol.ution ratio of 5:4 

(w:v). The samples were maintained in the dark at 25°C. After 24 hours of 

shaking, triplicate aliquots were analyzed using LSC. Based on the results, a 

soil:solution ratio of 1: 1 (w:v) was selected for [ 14C]-labeled flazasulfuron, TPSA, 

and DTPU treated soils, 1 :10 (w:v) was selected for [

14C]DTPP treated soils, and 

1 :1 (w:v; Golden Lake sand) and 1 :4 (w:v; WY clay) were selected for 

[

14C]ADMP treated soils (p. 32; Table V, p. 52). 

For Tier 2 tests, aliquots of Golden Lake sand and WY clay soils were prepared in 

O.OlM CaCh solution at soil:solution ratios of 1: 1, 1:4 or 1: 10 (w:v; pp. 23-26). 

The solutions were then dosed with [

14C]-labeled flazasulfuron, TPSA, DTPU, 

DTPP, and ADMP at ca. 5 mg/L. Soil-less controls and blank samples were also 

prepared. The samples were maintained in the dark at 25°C. After ca. 4, 6, 24, 29, 

and 48 hours of shaking, triplicate aliquots of [

14C]-labeled TPSA, DTPU, DTPP, 

and ADMP adsorption solutions were analyzed using LSC. Aliquots of the 

remaining soils were combusted and analyzed. For flazasulfuron, the test was 

terminated after 30 hours of shaking due to instability of the test substance. 

Triplicate aliquots of the adsorption solutions were analyzed using LSC, and 

aliquots of the remaining soils were combusted and analyzed. Aliquots of the soils 

treated at the highest test concentration were extracted three times with 

acetonitrile:water (9: 1, v:v) prior to HPLC analysis. Due to instability of 

flazasulfuron in solution, an equilibrium time of 24 hours was selected for the 

definitive study (p. 33). For the remaining samples, 24 hours was selected for 

soils treated with TPSA and DTPU and 48 hours was selected for soils treated 

with DTPP and ADMP. 

For the definitive study, duplicate aliquots of each soil were pre-equilibrated 

overnight with 0.01 M CaCh solution (pp. 26-27). Soil: solution ratios were 1: 1 

(w:v) for [

14C]-labeled flazasulfuron, TPSA, and DTPU treated soils, 1: 10 (w:v) 

for [

14C]DTPP treated soils, and 1: 1 (w:v; Golden Lake sand) and 1 :4 (w:v; WY 

clay) for (

14C]ADMP treated soils. Additional duplicate soil-less control samples 

were prepared at the highest test concentration. Following pre-equilibration, the 

samples were dosed to give nominal concentration ranges of 0.05 to 5 mg/L and 

shaken in the dark at 25°C for 24 hours (flazasulfuron, TPSA, and DTPU treated 

soils) or 48 hours (DTPP and ADMP treated soils). Following centrifugation, the 

supematants were decanted and analyzed. An equivalent volume of fresh sterile 

O.OlM aqueous CaCl2 was added to each test vessel and the samples were 

equilibrated in the dark at 25°C as specified for the adsorption phase. The samples 

were centrifuged and the supematants were decanted and analyzed. Aliquots of 

the remaining soils were combusted and analyzed. Aliquots of the soils treated at 

the highest test concentration were extracted three times by shaking with 

12of29 
Flazasulfuron (PC 119011) MRID 49030002 

acetonitrile:water (9:1, v:v) prior to analysis. 

2. Analytical procedures: Radioactivity in the aqueous supematants was 

determined by Liquid Scintillation Counting (LSC; pp. 20, 26-27). Desorption 

supematants and soil extracts collected from soils treated at the highest test 

concentration were analyzed for flazasulfuron using HPLC (Alltech Alltima AQ 

C-18, 5 μm column, gradient mobile phase of (A) l % phosphoric acid in HPLC 

water and (B) l % phosphoric acid in acetonitrile, with UV (240 nm) and 

radioactive flow detection; pp. 20-21, 27-28). The Limit of Detection (LOD) for 

LSC analysis was 0.00028 ppm for 0.05 ppm dose samples (p. 28). The LOD for 

combustion samples was 0.00063 ppm. The LOD and Limit of Quantification 

(LOQ) for HPLC analysis were 0.006 μgig and 0.003 μg/g, respectively (p. 29). 

II. Results and Discussion 

A. Mass Balance: For [

14C]flazasulfuron treated soils, recovery ranged from 96.2-

101.0% of the applied for Golden Lake sand and l 00.2-111.6% for WY clay (p. 34; 

Table VII, p. 58). 

For [

14C]TPSA treated soils, recovery ranged from 97.3-98.5% of the applied for Golden 

Lake sand and 97.6-101.1 % for WY clay (p. 34; Table VIII, p. 59). 

For [

14C]DTPU treated soils, recovery ranged from 92.1-99.1% of the applied for Golden 

Lake sand and 91.3-95.6% for WY clay (p. 34; Table IX, p. 60). 

For [

14C]DTPP treated soils, recovery ranged from 87.5-104.0% of the applied for 

Golden Lake sand and 88.4-190.1% for WY clay (p. 34; Table X, p. 61). 

For [

14C]ADMP treated soils, recovery ranged from 92.4-99.9% of the applied for 

Golden Lake sand and 81.8-99.3% for WY clay (p. 34; Table XI, p. 62). 

B. Transformation of Parent Compound: HPLC analysis of test soils treated at the 

highest test concentration (5 mg/L) showed that [

14C]flazasulfuron was unstable in both 

test soils with DTPU, STPP, and ADMP present as major degradates in each instance (p. 

34; Figure 5, pp. 87-93). Due to this instability, equilibrium concentrations were adjusted 

based on the percent flazasulfuron determined by HPLC analysis of each phase (p. 35). 

[

14C]-labeled TPSA, DTPU, DTPP, and ADMP were shown to be stable in both test soils 

treated at the highest test concentration and in control solutions for the duration of the 

study (Figures 6-9, pp. 94-117). 

C. Findings: Reported values were calculated using linear regression (Excel) and the 

equations and methods discussed in the calculations section. 

Equilibration concentrations in water were appropriate for all [

14C]-labeled flazasulfuron, 

TPSA, DTPU, DTPP, and ADMP treated soils, ranging from 0.0064-4.5557 μg/mL 

following the adsorption phase and 0.0004-0.5084 μg/rnL following desorption 

13 of29 
Flazasulfuron (PC 11901 1) MRID 49030002 

(Appendix G, pp. 203-204; Appendix H, pp. 212-213; Appendix I, pp. 221-222; 

Appendix J, pp. 232-233; and Appendix K, pp. 241 -242). Percent adsorption and percent 

desorption, as percent of the adsorbed, were not determined. Coefficients of variation 

(CV) ranged from 0.02 to 1.1 and 0.2 to 0.8 across all [

14C]-treated soils for adsorption 

K F and K Foc, respectively, and 0.03 to 0.7 and 0.1 to 0.6 across all (

14C]-treated soils for 

desorption KF and KFoc, respectively (DER Attachment). 

T a e bl 3 . D escrmtlon o fAd sorp f ton c oe ffi 1c1en . t s 

Soil I Kd (L/kg) I Koc I KF (L/kg) I K Foc 

(14C)Flazasulfuron 

Golden Lake Sand I 0.20 I 67 I 0.23 I 77 

WY Clay I 0.10 I 12 I 0.16 I 20 

[

14C]TPSA 

Golden Lake Sand I 0.10 I 35 I 0.11 I 35 

WYClav I 0.10 I 12 I 0.11 I 14 

[

14C]DTPU 

Golden Lake Sand I 0.42 I 140 I o.5o I 166 

WY Clay I o.63 I 79 I o.67 I 83 

[

14

C]DTPP 

Golden Lake Sand I 5.04 I 1679 I 5.94 I 1980 

WYClav I 9.12 I 1140 I 1 t.78 I 1473 

r'4ClADMP 

Golden Lake Sand I o.39 I 130 I o.55 I 184 

WY Clay I 3.20 I 400 I 5.03 I 628 

T a bl e 4 . D escr1pt10n o f D esorphon c oe ffi 1c1ents . 

Soil I Kdes (Lf.kg) I Koc-des I KFdes (L/kg) I K Foc-ges 

( 

14

C]Flazasulfuron 

Golden Lake Sand I 0.92 I 308 I o.89 I 298 

WY Clay I 1.17 I 146 I o.93 I 116 

r

14

ClTPSA 

Golden Lake Sand I 1.08 I 358 I uo I 367 

WY Clay I 3.44 I 430 I 2.13 I 266 

['

4

C]DTPU 

Golden Lake Sand I 1.89 I 631 I 1.69 I 562 

WYClav I 4.46 I 557 I 4.96 I 619 

(

14

C]DTPP 

Golden Lake Sand I 41.69 I 13898 I 37.67 I 12557 

WY Clay I 92.67 I 11583 I 77.63 I 9703 

r

14ClADMP 

Golden Lake Sand I 5.29 I 1764 I 4.49 I 1497 

WY Clay I 14.76 I 1845 I 13.06 I 1632 

Reviewer-reported Freundlich sorption coefficients were mostly in agreement with the 

study-reported values (Tables XII-XXIII, pp. 63-74; Figures 10-19, pp. 1] 8-127). There 

were a few reviewer-reported values that differed slightly from study-reported values due 

to rounding errors. 

Since only two types of soils were used for the test, regression of~ by percent organic 

carbon, CEC, and percent clay was not valid. 

14 of29 
Flazasulfuron (PC 119011) MRID 49030002 

T ba l e 5 . S ummary o f R ef!resse d Kd 0

A oc CEC d vs 0 0A Cl ' , an 0 ay 

Parameter r p-value 

Kd vs. % organic carbon NIA NIA 

Kd VS. CEC 

Kd vs. % clav 

Ill. Study Deficiencies and Reviewer's Comments 

The following deviations were noted: 

1. The study was conducted using the parent compound flazasulfuron, as well as 

four transformation products. 

2. The position of the radio label for the test substance flazasulfuron was different in 

the chemical structures provided in the study report (pp. 75 and 129; Appendix B, 

p. 140). The position of the radiolabel for the test substances DTPU and DTPP 

were also different in the chemical structures provided (pp. 75 and 129). In 

addition, the chemical structures for ADMP and TPSA presented in Figure 1, p. 

7 5 of the study report were reversed. 

3. The study was conducted using only two types of soils. 

4. The parent compound was found to be highly unstable in solution, with 

significant degradation. 

Using the McCall Classification scale, the study author predicted the following: 

Table 6. Summary of Mobility Classification, based on McCall et.al. 

Treatme.nt Golden Lake Sand WY Clay 

r

14

ClFlaz.asulfuron Hi!ili Very high 

['

4

ClTPSA Very high Very high 

r

14

ClDTPU Medium High 

r'4ClDTPP Low Low 

['

4

C]ADMP Medium Low 

Data were obtained from pp. 41-42 of the study report. 

IV. References 

I. U.S. Environmental Protection Agency. 2008. Fate, Transport and Transformation 

Test Guidelines, OPPTS 835.1230, adsorption/desorption (batch equilibrium). Office 

of Prevention, Pesticides and Toxic Substances, Washington, DC. EPA 712-C-08-

019. 

15of29 
Flazasulfuron (PC 119011) MRID 49030002 

DER ATTACHMENT 1. 

Table 1. Flazasulfuron and Its Environmental Transformation Products. A 

Code Name/ ' StUdy Maximum Final o/oAR Chemical Name Chemical Structure MRID Synonym Type %AR(day) (study length) 

PARENT 

Flazasulf uron IUPAC: l-(4,6-

(SL-160) Dimethoxypyrimidin-2-yl)-

3-(3-trifluoromethyl-2-

pyridylsulfonyl)urea 

CAS: N-[[(4,6-dimethoxy-2-

~~--~--<~ CH3 pyrimidinyl)amino ]carbonyl] 

-3-(trifluoromethyl)-2- 835. 1230 

pyridinesulfonamide ~ ! ! N- . Batch 49030002 NA NA 

equilibrium 

CAS No.: 104040-78-0 · 0-CH3 F 

Formula: C13.H12F3NsOsS 

MW: 407.3 g/mol 

SMILES: 

n I cccc( C(F)(F)F)c IS( =0)( =O) 

NC( =O )Nc2nc( OC)cc( OC)n2 

MAJOR(> 10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED . 

All compounds used as reference compounds were identified. A " . . " AR means applied rad1oact1v1ty . MW means " molecular weight " . NA means " not applicable " . 

16 of29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 2. DTPU and Its Environmental Transformation Products. " 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final %AR 

Synonym Type~ %AR(day) (study length) 

PARENT 

DTPU I UPAC: 1-( 4,6-Dimethoxypyrimidin- /CH3 

2-yl)-1 -[3-(trifluoromethyl)-2- 0 

pyridyl]urea F F 

'Formula: C13H12F3Ns03 7 I ~ 

I MW: 343.26 g/mol 

>~. 835.1230 

SMILES: ~ Batch 49030002 NA NA COc I cc( nc( n I )N ( c2c( cccn2 )C(F)(F)F N 0 equilibrium )C(=O)N)OC ",.Ao I 

CH3 

I 

H 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. A " .. " " ,, II II AR means applied rad1oac11v1ty . MW means molecular weight . NA means not applicable . 

17 of29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 3. DTPP and Its Environmental Transformation Products. A 

Code Name/ CbemicaJ Name Chemical Structure Study MRID Maximum Final %AR 

Synonym - Type %AR(day) (study length) 

PARENT 

DTPP IUP AC: 4,6-Dimethoxy-2-(3- /CH3 trifluoromethyl-2- 0 

pyridylamino )pyrimidine F F 

Formula: C12H11f3N402 ~ N ::;/" 835.1230 

MW: 300.24 g/mol I :A I Batch 49030002 NA NA 

SMILES: ~ equilibrium 

COc I cc(nc(n 1 )Nc2c( cccn2)C(F)(F)F) N 0 

oc I I 

H CH3 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. A " . . ,, AR means applied rad1oact1v1ty " " " " . MW means molecular weight . NA means not applicable . 

18 of29 
Flazasulfuron (PC 11901 l) MRID 49030002 

Table 4. ADMP and Its Environmentai Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final o/oAR 

Synonym Type %AR(day) (study length) 

PARENT 

ADMP IUP AC: 2-Amino-4,6-

dimethoxypyrimidine . 

F

MW

ormula: C6H9N30 2 H'N-1~-CH3 835.1230 : 155. 15 g/mol 

SMILES: COc l cc(nc(n l)N)OC Batch 49030002 NA NA I - equilibrium H N 

0-CH3 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

. No major transformation products were identified. . 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. A " . . '' " ,, AR means applied rad1oactiv1ty . MW means molecular weight . NA means " not applicable " . 

19 of29 
Flazasulfuron (PC 119011) MRlD 49030002 

Table 5. TPSA and Its Environmental Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final o/oAR 

Synonym Type %AR(day) (study length) 

PARENT 

TPSA IUPAC: 3-Trifluoromethyl-2-

pyridinesulphonamide oc: Formula: C6H5f3N202S 

MW: 226.18 g/mol 835.1230 

SMILES: 0 Batch 49030002 NA NA 

N s?' H c I cc{ c(nc I )S(=O)(=O)N)C(F)(F)F I f''w"'..--- equilibrium 

o I 

H 

MAJOR(> 10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

·REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. A " .. ,, " ,, AR means applied rad1oactiv1ty " " . MW means molecular weight . NA means not applicable . 

20 of29 
F lazasu I furon (PC 1 190 I I) MRID 49030002 

DER ATTACHMENT 1. 

Table 1. Flazasulfuron and Its Environmental Transformation Products. A 

Code Name/ Study r Maximum Final 0

A>AR Chemical Name Chemical Structure IMRID Synonym Type %AR(day) (study length) 

PARENT 

Flazasulfuron IUPAC: 1-(4,6-

(SL-160) Dimethoxypyrimidin2-yl)-3-(3-

trifluoromethyl-2-

pyridylsulfooyl)urea 

CAS: N-1((4,6-

dimethoxy-2-

pyrimidinyl)amino)car 

bonyl)-3- N II O ~ N 

-CH3 835.1230 

( trifluoromethyl)-2- S-N N-< ~ Batch 4903000 NA NA pyridinesulfonamide II 0 H H I I N- . equilibriu 2 

O-CH3 m 

CAS No.: 104040-78-0 F 

Formula: 

C13H12F3NsOsS 

MW: 407.3 g/mol 

SMILES: 

nlcccc(C(F)(F)F)clS(= 

O)(=O)NC(=O)Nc2nc( 

OC)cc(OC)n2 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

21 of 29 
Flazasulfuron (PC 119011) MRID 49030002 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final %AR 

Synonym Type %AR(day) (study length) 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. 

A " . . " " . AR means apphed radroachv1ty . MW means molecular weight " . NA means " not apphcable " . 

22 of29 
Flazasulfuron (PC 11901 1) MRJD 49030002 

Table 2. DTPU and Its Environmental Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final 0

/oAR 

Synonym Type %AR(day) (study length) 

PARENT 

DTPU IUPAC: 1-(4,6- / CH3 

Dimethoxypyrimidin-2-yl)-1- 0 

[3-( trifluoromethyl)-2- F F 

pyridyl]urea ~ N ::/"' 835.1230 

Formula: C13812F3Ns03 :::::-.... 

I :A I Batch 4903000 NA NA 

MW: 343.26 g/mol N 0 equilibriu 2 

SMILES: 

",.Ao I m 

C0clcc(nc(nl)N(c2c(cccn2)C 

CH3 

(F)(F)F)C(=O)N)OC I 

H 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. A . .. AR means "applied radioactivity". MW means "molecular weight". NA means "not applicable" . 

23 of 29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 3. DTPP and Its Environmental Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final %AR 

Synonym Type %AR(day) (study length) 

PARENT 

DTPP IUP AC: 4,6-Dimethoxy-2-(3-

trifluoromethyl-2- /CH3 

pyridylamino )pyrimidine 0 

F F 

835.1230 

Formula: C12H11F3N402 ~ N :;:/' Batch 4903000 

MW: 300.24 g/mol I :A I equilibriu 2 NA NA 

SMILES: ~ m N 0 

COclcc(nc(nl)Nc2c(cccn2)C( I I F)(F)F)OC H CH3 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. 

A " .. " " I AR means apphed " rad1oachv1ty . MW means molecular weight". NA means ' not apphcable . 

24 of 29 
Flazasulfuron (PC I 190 I I) MRJD 49030002 

Table 4. ADMP and Its Environmental Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final 0/oAR 

Synonym Type %AR(day) (study length) 

PARENT 

ADMP IUP AC: 2-Amino-4,6-

dimetboxypyrimidine 

H'N--<!~0-C 3 

Formula: C6H9N302 835.1230 

Batch 4903000 MW: 155.15 g/mol equilibriu 2 NA NA 

SMILES: I - H N 

COclcc(nc(nl)N)OC m 

O-CH3 

MAJOR (>10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. 

A " . . " " " AR means . I apphed rad10achv1ty . MW means molecular weight". NA means not applicable' . 

25 of29 
Flazasulfuron (PC 119011) MRID 49030002 

Table 5. TPSA and Its Environmental Transformation Products. A 

Code Name/ Chemical Name Chemical Structure Study MRID Maximum Final %AR 

Synonym Type %AR(day) (study length) 

PARENT 

TPSA IUP AC: 3-Trifluoromethyl-2-

pyridinesulphonamide 

oc: Formula: C6HsF3N202S 835.1230 

MW: 226.18 g/mol 0 Batch 4903000 NA NA SMILES: N s? H equilibriu 2 

cl cc( c(ncl)S(=O)(=O)N)C(F)( I f''w',,. m 

F)F o I 

H 

MAJOR(> 10%) TRANSFORMATION PRODUCTS 

No major transformation products were identified. 

MINOR (<10%) TRANSFORMATION PRODUCTS 

No minor transformation products were identified. 

REFERENCE COMPOUNDS NOT IDENTIFIED 

All compounds used as reference compounds were identified. 

A " .. " " . AR means " " " apphed radt0acttv1ty . MW means molecular weight . NA means not applicable . 

26 of29 
FlazasuJfuron (PC 119011) MRID 49030002 

Attachment 2: Statistics Spreadsheets and Graphs 

27 of29 
F=la=za=s=u=fu=r=o=n~(P~C~l~l9~0~1~1).__~~~~~~~~~~~~~~~~~ lD 030002 

Attachment 3: Calculations 

Calculations were performed by the reviewer using Excel and the following equations. 

Ceq range is the range of test concentrations in water at equilibrium. 

Cs is the test concentrations sorbed to soil or sediment at equilibrium. 

~ - Distribution Coefficient for Adsorption = C5/Ceq (eq 1) 

• Regressed Kd is calculated using linear regression of Cs versus Ceq with a 

forced zero intercept over the range of measured Ceq for each soil/sediment. 

• Range of Kd reflects the range of each Kd measured at a specific concentration 

in a soil/sediment 

Koc -Organic Carbon Normalized Adsorption Coefficient = regressed Kd * 100/% OC ( eq 

2) 

Standard Error (SE) of Koc= Kd SE * 100/%0C (eq 3) 

KF -Freundlich Adsorption Coefficient and the Freundlich exponent (1 /n) were calculated 

using nonlinear regression of Cs = KF x Ceq 11

". Cs should be expressed in mg/kg and Ceq 

should be expressed in mg/Lin the regression. (eq 4) 

KFOc -Organic Carbon Normalized Adsorption Coefficient = KF* 100/%0C 

Standard Error (SE) of KFoc= KF SE * 100/%0C 

(eq 5) 

(eq 6) 

KoES - Apparent Desorption Coefficient = C5/Ceq where Cs and Ceq are measured after an 

initial sorption measurement and the soil/sediment is placed in a new solution and 

allowed to equilibrate, so that any material in solution desorbed from the soil/sediment. 

(eq 7) 

• Regressed KoEs is calculated using linear regression of Cs versus Ceq over the 

range of Ceq measured with a forced zero intercept for each soil/sediment. 

• Range ofKoEs reflects the range of each KoEs measured at a specific 

concentration in a soil/sediment 

Koc-DES -Organic Carbon Normalized Apparent Desorption Coefficient = regressed KoEs 

*100/% OC (eq 8) 

Standard Error of Koc-oEs = KoEs SE* 100/%0C (eq 9) 

K F-DES -Freundlich Desorption Coefficient and the Freundlich Desorption exponent (l/n) 

were calculated using nonlinear regression of Cs = KF-DES x Ceq 11" ( eq 10) 

28 of29 
Flazast lfuron CPC 119011) MRID 49030002 

KFOc-oEs -Organic Carbon Normalized Freundlich Desorption Coefficient= Kr. 

DES* 100/%0C (eq 11) 

Standard Error of K FOc-DES = KF SE * 100/%0C ( eq 12) 

29 of29