++<ED UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D. C. 20460 

OFFICE OF 

PREVENTION, PESTICIDES 

AND TOXIC SUBSTANCES 

DP Barcodes: D3V 1784 

Date: January 28,2010 

SUBJECT: Tier I1 Drinking Water Assessment of Bifenazate (PC Code: 000586; GAS # 

149877-41-8) and the Degradate of Toxic Concern (D1989) for the ~rd~osed New 

Uses on Avocado, Tropical Fruit, Low Growing Berry, and Small ~iie 

Climbing Fruit 

TO: Barbara Madden, RM 05 

Risk Integration Minor Use, and Emergency Response Branch 

Registration Division (7505P) 

Dana Vogel, Branch Chief 

Risk Assessment Branch I 

Health Effects Division (7509P) 

FROM: Mark Corbin, Senior En ' 

Dana Spatz, Branch Chi 

Environmental Risk Branc 

Environmental Fate and Effects Division (7507P) \ \ \ \ 

Executive Summary 

This document contains the Tier I1 Estimated Drinking Water Exposure Concentratiojs (EDWC) 

of bifenazate (isopropyl3-(4-methoxy biphenyl-3-yl) carbazate, CAS # 149877-41-8)! and the 

bifenazate degradate, D 1989 (4-methoxybiphenyl, CAS # 6 13-37-6), in surface and qround 

water for proposed new uses on Avocado, Tropical Fruit , Low Growing Berry , and S/mall Vine 

Climbing Fruit. The new use rates are similar to those recently assessed in October 2409 and are 

summarized in Table1 . I 

I 

l llllll lll lul lll lllll lllll lllll Il1 Il1 

2084482 

TEXT SEARCHABLE DOCUMENT - 2010
ropical Fruit (LA sugarcane)' 

ow Growing Berry (FL strawberry) 

Small Vine Climbing Fruit (NY grapes) 

Bifenazate has been previously assessed several times with the most recent drinking m!ater 

assessment completed in August 3,2009 (D366486). Additional assessments were completed on 

November 21,2001, October 24,2006, and September 2008. 

Based on available fate data, bifenazate (hydrazine carboxylic acid, 2-(4-methoxy-[l , 1'- 

biphenyl]-3-y1)-methylethyl ester) and the initial degradate, diazene (D3598) would bb expected 

to dissipate rapidly under most environmental conditions, with half-lives in the range of hours. 

The relatively stable degradate 4-methoxybiphenyl (D1989) is a major soil metabolite, and is 

more persistent relative to the parent bifenazate. The aerobic soil metabolism half-life for the 

major bifenazate degradate, D1989, is estimated to be about two2 or three months3. qile the 

parent compound, bifenazate, degrades too rapidly to accurately determine a specific &, value, 

\ laboratory data indicates that both bifenazatq, and the Dl989 degradation product, will be , slightly mobile. The degradation product Dl989 has the potential to reach surface water and 

ground water due to the persistence of Dl989 relative to the parent compound, bifenaaate. 

Because of the rapid conversion of parent to Dl989 and the equivalent toxicity of Dl489 

previous assessments have modeled the degradate and this assessment adopts that approach. The 

modeled application rate was adjusted to account for the persistence of the degradation product 

relative to the parent compound, and the assumption that 100% of bifenazate converts into 

degradate D1989. Differences in molecular weight of bifenazate and the degradation product, 

D1989, were adjusted using the following equation: 

Modeled Application Rate = Labeled Application Rate of Bifenazate 

X (Molecular Weight of Dl989 / Molecular Weight of Bifenazate) 

The maximum reported EDWC from these previous assessments was 37.3 ppb for aer;ial spray to 

dry beans. The maximum EDWC from this assessment yielded a peak concentration of 21.3 ppb 

1 Tropical Fruit previously assessed in D366481 dated August 3, 2009 

Calculated by EFEDI J.Jordon from MRID 45 1440-02 

3 Repo,ped in HED Metabolism Assessment Review Committee (MARC) Decision Document 
for low growing berries (strawberry scenario). 

Analysis Plan 

This assessment provides EDWC for bifenazate and it's degradate (D1989). Dl889 is included 

in the DWA because it has been deemed to be a degradate of concern for human health effects. 

This assessment relies upon both existing and new environmental fate data (MRID 4767902) for 

the estimation of model inputs. EFED calculated the half-life for summed bifenazate residues 

(parent and D1989) in aerobic soil metabolism studies. The upper 9oth percentile of the mean 

aerobic soil metabolism half-life for bifenazate residues (bifenazate + D1989) is 42.7 days. This 

half-life was used in the exposure modeling. The &, for Dl989 was used in exposure modeling 

because it was lower than parent bifenazate. 

PRZM (Version 3.1.22)lEXAMS (Version 2.98.06) models in the PE5 shell were used to 

estimate Tier I1 EDWC in surface water. The SCI-GROW (Version 2.3) model was used to 

estimate the Tier 1 EDWC in ground water. Model inputs were derived from supplemental and 

acceptable registrant submitted data for bifenazate. Modeling scenarios used in this assessment 

were selected to yield the highest EDWC from all available scenarios based on availability and 

runoff potential. An exception to this is the tropical fruit use which was previously aslsessed in 

2009 and whose EDWC are used here. Model inputs for PRZM/EXAMS and SCIGRQW are 

summarized in Table 2 and Table 3, respectively. 

For drinking water exposure assessments EFED uses a percent cropped area (PCA) adjustment 

factor to account for the percentage of a watershed cropped to agriculture. For this aqessment, 

the default (87%) PCA has been applied because bifenazate can be applied to multiple crops. 

(adjusted from 0.75 

lblacre due to 

2 applications @ molecular wt 

0.45 lblacre - 

fruit, & low 

growing berry 

9oth% of five Aerobic Soil 

42.7 days individual TTR half Metabolism MRID 45 144002 

lives (60,21.1,23.3, MRD 47607902 

t l/, 21.4, and 3 1.2 days) 
Table 2. PRZM/EXAMS Input Parameters for Total Residues of Bifenazate TTR 

(Parent plus D1989) for IRJPCA Drinking Water Assessment 

Model Parameter Value Comments Source 

Aerobic Aquatic 2x aerobic soil 

Degradation 85.4 days metabolism EFED Guidance 

t ?h 

Aqueous Photolysis Stable no data available for mID 44464953 

t l/, degradate , 

Hydrolysis Stable no data available for mID d44649i2 I degradate 

Koc 

Due to bifenazate's 

rapid degradation in 

aerobic soil study 

and immobility in 

301 1 mllg-OC soil column study, MRID 44464955 

the lowest non-sand MRID 44464956 

(silt loam) Koc for 

the major degradate 

Dl989 was modeled. 

EPI Suite 2000 

Water Solubility 3.8 ppm value for degradate (v3. 12) bsKOW used 

Fate and Transport of Pestjcjdes"dated February 28,2002. 

1 application @ 

0.45 lblacre - 

small vine 

Application Rate & Max. climbing fruit 

Number of Application Product Labkl 2 applications @ 

0.45 lblacre - 

avocado, tropical 

fruit, & low 
Modeling Results 

The EDWC for surface water are shown in Table 4. The tropical fruit use generated the highest 

1 in 10 year peak EDWC (16.7 pg/L). The EDWC for ground water are shown in Table 5. 

Low Growing Berry 

Table 5: EFED EDWC (pg/L) in Groundwater for Bifenazate 

(Combined Residues) 

Application 

Use Rate & # of DWEC (ppb) 

Applications I Small Vine Climbing Fruit 0.45 lbs ailacre 8.2 E-3 

1 aPP 

Avocado 0.45 lbs ailacre Tropical Fruit 1.6 E-2 

Low Growing. Berrv 2 aPPs 

I 
APPENDIX A 

PRZM/EXAMS & SCIGROW MODEL OUTPUT 

PRZM/EXAMS 

stored as CA avocado air Eco.out 

Chemical: bifenazate 

PRZM environment: 

CAAvocadoRLF-V2.txt modified Wedday, 26 March 2008 at 09:28:12 

EXAMS environment: 

pond298.e~~ modified Tueday, 26 August 2008 at 05:14:08 

Metfile: w23188.dvf modified Tueday, 26 August 2008 at 05:15:38 

Water segment concentrations (ppb) 

Year 

Sorted results 

Prob. 

Peak 

1961 1.797 

1962 2.1 9 

1963 2.22 

1964 2.422 

1965 4.181 

1966 2.927 

1967 2.824 

1968 2.778 

1969 4.03 

1 970 2.668 

1971 2.538 

1 972 2.38 

1973 2.393 

1974 2.433 

1 975 2.604 

1 976 2.61 1 

1977 3.525 

1978 2.783 

1979 2.747 

1980 2.723 

1981 2.633 

1982 2.696 

1983 2.552 

1984 2.34 

1985 4.781 

1986 2.928 

1 987 2.71 7 

1988 2.706 

1989 2.473 

1 990 2.41 1 

Peak 

0.032258 4.781 

21 Day 

1.076 

1.458 

1 584 

1.686 

3.053 

2.1 88 

2.083 

2.037 

2.767 

1.926 

1.797 

1.638 

1.649 

1.742 

1.861 

1.91 1 

2.54 

2.099 

2.038 

1.983 

1.892 

1.954 

1.81 

1.597 

3.214 

2.191 

1.976 

1.963 

1.73 

1.668 

60 

Day 90 Day 

0.7748 

1.156 

1.185 

1.382 

2.324 

1.871 

1.767 

1.722 

2.121 

1.614 

1.488 

1.327 

1.343 

1.349 

1.547 

1.546 

2.01 7 

1.729 

1.693 

1.659 

1.576 

1.632 

1.496 

1.293 

2.339 

1.867 

1.658 

1.648 

1.422 

1.362 

60 

96 hr 21 Day Day 90 Day 

4.328 3.214 2.339 

Yearly 

0.248 

0.6857 

0.791 8 

0.9203 

1.137 

1 535 

1.438 

1.302 

1.481 

1.219 

1.059 

0.951 5 

0.8855 

0.9713 

1.096 

1.17 

1.318 

1.356 

1.327 

1.296 

1.21 1 

1.231 

1.064 

0.8596 

1.143 

1.581 

1.31 1 

1.24 

0.9789 

0.9282 

Yearly 

1 581 
0.1 3.9795 3.6332 2.7443 2.1 106 1.8326 1.4767 

Average of yearly 

averages: 1.124527 

Inputs generated by pe5.pl- Novemeber 2006 

Data used for this run: 

Output File: CA avocado air Eco 

Metfile: 

PRZM scenario: 

EXAMS environment file: 

Chemical Name: 

Description 

Molecular weight 

Henry's Law Const. 

Vapor Pressure 

Solubility 

Kd 

Koc 

w23188.dvf 

CAAvocadoRLF-V2,txt 

pond298.exv 

bifenazate 

Variable 

Name Value Units Comments 

mwt 184 g/mol 

henry atm-mA3/mol 

3.80Evapr 04 torr 

sol 27.7 mg/L 

Kd mg/L 

Koc 3011 mg/L 
Photolysis half-life 

Aerobic Aquatic Metabolism 

Anaerobic Aquatic Metabolism 

Aerobic Soil Metabolism 

Hydrolysis: 

Hydrolysis: 

Hydrolysis: 

Method: 

Incorporation Depth: 

Application Rate: 

- Application Efficiency: 

Spray Drift 

Application Date 

Interval 1 

app. rate 1 

Record 17: 

Record 18: 

Flag for Index Res. Run 

Flag for runoff calc. 

kdp 

kbacw 

kbacs 

asm 

pH 9 

CAM 

DEPl 

TAPP 

APPEFF 

DRFT 

Date 

interval 

apprate 

FILTRA 

IPSCND 

UPTKF 

PLVKRT 

PLDKRT 

FEXTRC 

IR 

RUNOFF 

Halfdays life 

days Halfife 

days Halfife 

days Halfife 

Halfdays life 

Halfdays life 

Halfdays life 

integer See PRZM manual 

cm 

kglha 

fraction 

fraction of application rate applied td pond 

ddlmm or ddtmmm or dd-mm or dd-pmm 

days Set to 0 or delete line for single app. 

kglha 

0.5 

EPA Pond 

none none, monthly or total(average of entire run) 
stored as FL strawberry air Eco.out 

Chemical: bifenazate 

PRZM environment: modified Tueday, 29 May 2007 at 

FLstrawberry-WirrigSTD.txt 12:53:40 

EXAMS environment: 

pond298.exv modified Tueday, 26 August 2008 at 05:14:08 

Metfile: w12842.dvf modified Tueday, 26 August 2008 at 05:14:20 

Water segment concentrations (ppb) 

Year 

Sorted results 

Prob. 

Peak 

3.1 98 

7.051 

4.907 

9.066 

11.34 

6.469 

11.41 

7.097 

10.59 

7.364 

9.768 

10.41 

8.889 

5.232 

6.407 

8.356 

5.156 

5.146 

8.936 

6.776 

8.225 

8.1 56 

8.51 3 

7.502 

11.52 

6.332 

6.866 

13.06 

8.296 

7.476 

60 

21 Day Day 

2.287 2.085 

5.253 4.543 

3.822 3.542 

7.149 6.494 

8.683 6.579 

5.743 4.918 

8.488 6.18 

5.898 5.355 

8.89 7.176 

6.226 5.343 

7.424 6.556 

8.496 6.484 

7.213 6.85 

4.464 4.21 

5.28 4.867 

6.049 5.074 

4.305 4.062 

4.479 3.913 

7.632 6.98 

5.846 5.309 

6.358 5.694 

6.732 6.325 

7.148 6.482 

6.198 5.525 

8.274 6.993 

5.518 5.199 

5.935 5.334 

9.642 8.057 

7.326 6.451 

6.32 5.388 

90 Day 

60 

Peak 96 hr 21 Day Day 90 Day 

0.032258 13.06 11.96 9.642 8.057 

0.06451 6 11.52 10.71 8.89 7.176 

0.096774 11.41 10.58 8.683 6.993 

0.129032 11.34 10.34 8.496 6.98 

0.16129 10.59 9.776 8.488 6.85 

Yearly 

0.7063 

1.952 

2.455 

3.279 

3.803 

3.446 

3.553 

3.757 

4.258 

3.802 

3.905 

4.156 

4.21 2 

3.353 

3.1 35 

3.31 3 

2.98 

2.832 

3.845 

3.823 

3.568 

4.204 

4.233 

3.823 

4.114 

4.042 

3.827 

4.359 

4.633 

3.892 

Yearly 

4.633 

4.359 

4.258 

4.233 

4.212 
6.41 58 

Average of yearly 

averages: 

Inputs generated by pe5.pl- Novemeber 2006 

Data used for this run: 

Output File: FL strawberry air Eco 

Metfile: 

PRZM scenario: 

EXAMS environment file: 

Chemical Name: 

Description 

Molecular weight 

Henry's Law Const. 

Vapor Pressure 

Solubility 

Kd 

Koc 

Photolysis half-life 

Aerobic Aquatic Metabolism 

Anaerobic Aquatic Metabolism 

wl2842.dvf 

FLstrawberry-WirrigSTD.txt 

pond298.e~~ 

bifenazate 

Variable 

Name Value Units Comments 

mwt 184 glmol 

henry atm-mA3/mol 

3.80Evapr 04 torr 

sol 27.7 mg/L 

Kd mg/L 

Koc 3011 mg/L 

Halfkdp 0 days life 

kbacw 360 days Halfife 

kbacs days Halfife 
Aerobic Soil Metabolism 

Hydrolysis: 

Hydrolysis: 

Hydrolysis: 

Method: 

Incorporation Depth: 

Application Rate: 

Application Efficiency: 

Spray Drift . 

Application Date 

Interval 1 

app. rate 1 

Record 17: 

Record 18: 

Flag for Index Res. Run 

Flag for runoff calc. 

asm 

pH 5 

pH 7 

pH 9 

CAM 

DEPl 

TAPP 

APPEFF 

DRFT 

Date 

interval 

apprate 

FILTRA 

IPSCND 

UPTKF 

PLVKRT 

PLDKRT 

FEXTRC 

I R 

RUNOFF 

days Halfife 

Halfdays life 

Halfdays life 

Halfdays life 

integer See PRZM manual 

cm 

kglha 

fraction 

fraction of application rate applied to pond 

ddlmm or ddlmmm or dd-mm or dd-mmm 

days Set to 0 or delete line fqr single app. 

kglha 

0.5 

EPA Pond 

none none, monthly or total(average of entire run) 
stored as NY grapes air Eco.out 

Chemical: bifenazate 

PRZM environment: modified Tueday, 29 May 2007 at 

NYGrapesSTD.txt 12:59:44 

EXAMS environment: 

pond298.exv modified Tueday, 26 August 2008 at 05:14:08 

Metfile: w14860.dvf modified Tueday, 26 August 2008 at 051 512 

Water segment concentrations (ppb) 

Year Peak 

1961 1.251 

1962 3.471 

1963 2.078 

1 964 3.671 

1965 5.105 

1966 3.005 

1967 5.882 

1968 2.28 

1 969 2.101 

1 970 4.87 

1971 3.336 

1972 4.225 

1 973 2.212 

1974 2.249 

1975 3.257 

1976 2.232 

1977 3.699 

1978 4.302 

1979 4.756 

1980 5.89 

1981 3.337 

1982 3.271 

1983 4.176 

1 984 3.26 

1 985 4.024 

1986 3.093 

1987 3.694 

1988 3.1 98 

1989 2.26 

1990 2.995 

21 Day 

0.761 7 

2.422 

1.63 

2.683 

3.51 7 

2.291 

4.01 6 

1.78 

1.525 

3.41 8 

2.51 6 

3.039 

1.675 

1.748 

2.639 

1.796 

2.981 

3.31 9 

3.486 

4.257 

2.85 

2.626 

3.488 

2.538 

3.244 

2.41 8 

2.797 

2.438 

1.787 

2.382 

90 Day 

Sorted results 

60 

Prob. Peak 96 hr 21 Day Day 90 Day 

0.032258 5.89 5.429 4.257 3.724 

0.06451 6 5.882 5.356 4.016 3.157 

0.096774 5.105 4.665 3.517 2.933 

0.129032 4.87 4.42 3.488 2.844 

0.16129 4.756 4.41 3.486 2.763 

Yearly 

0.1739 

0.81 48 

1.127 

1.324 

1.629 

1:436 

1.549 

1.322 

1.04 

1.358 

1.636 

1.641 

1.277 

1.125 

1.525 

1.293 

1.443 

1.912 

2.142 

2.459 

2.207 

1.904 

1.872 

1.751 

1.658 

1.558 

1.697 

1.641 

1.34 

1.206 

Yearly 

2.459 

2.207 

2.142 

1.912 

1.904 
Inputs generated by pe5.pl - Novemeber 2006 

Data used for this run: 

Output File: NY grapes air Eco 

Metfile: wl4860.dvf 

PRZM scenario: NYGrapesSTD.txt 

EXAMS environment file: pond298.exv 

, Chemical Name: bifenazate 

Variable 

Description Name Value 

Molecular weight mwt 184 

Henry's Law Const. henry 

3.80EVapor Pressure vapr 04 

Solubility sol 27.7 

Kd Kd 

Koc Koc 301 1 

Photolysis half-life kdp 0 

Aerobic Aquatic Metabolism kbacw 360 

Anaerobic Aquatic kbacs 

2.6564 2.1 19 

Average of yearly 

averages: 1.502023 

Units Comments 

g/m ol 

atm-mA3/mol 

torr 

m g/L 

m g/L 

m g/L 

Halfdays life 

days Halfife 

days Halfife 
Metabolism 

Aerobic Soil Metabolism 

Hydrolysis: 

Hydrolysis: 

Hydrolysis: 

Method: 

Incorporation Depth: 

Application Rate: 

Application Efficiency: 

Spray Drift 

Application Date 

Record 17: 

Record 18: 

Flag for Index Res. Run 

Flag for runoff calc. 

asm 

PH 9 

CAM 

DEPl 

TAPP 

APPEFF 

DRFT 

Date 

FILTRA 

IPSCND 

UPTKF 

PLVKRT 

PLDKRT 

FEXTRC 

IR 

RUNOFF 

days Halfife 

Halfdays life 

Halfdays life 

Halfdays life 

integer See PRZM manual 

cm 

kglha 

fraction 

fraction of application rate applied to podd 

ddlmm or ddlmmm or dd-mm or dd-mmlm 

0.5 

EPA Pond 

none none, monthly or total(average of entire run) 
SCIGROW 

VERSION 2.3 

ENVIRONMENTAL FATE AND EFFECTS DIVISION 

OFFICE OF PESTICIDE PROGRAMS 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

SCREENING MODEL 

FOR AQUATIC PESTICIDE EXPOSURE 

SciGrow version 2.3 

chemicakbifenazate 

time is 81 312009 9: 7: 9 ........................................................................ 

Application Number of Total Use Koc Soil Aerobic 

rate (lblacre) applications (lb/acrelyr) (ml/g) metabolism (days) ---------------------------------------------------------+-------------- 

0.450 2.0 0.900 3.01E+03 42.7 ........................................................................ 

groundwater screening cond (ppb) = 1.64E-02 

*****************************%*%**%**%**%*****%****************%***%  

SCIGROW 

VERSION 2.3 

ENVIRONMENTAL FATE AND EFFECTS DIVISION 

OFFICE OF PESTICIDE PROGRAMS 

U.S. ENVIRONMENTAL PROTECTION AGENCY 

SCREENING MODEL \ FOR AQUAT~ PESTICIDE EXPOSUM 

SciGrow version 2.3 

chemical: bifenazate 

time is 81 312009 9: 9:57 ---_--_--_----_-_-------------------------T----------------------------- 

Application Number of Total Use Koc Soil Aerobic 

rate (lb/acre) applications (lblacrelyr) (mllg) metabolism (days) ........................................................................ 

0.450 1 .O ' 0.450 3.01E+03 42.7 ------------------------------------------------------------------------ 

groundwater screening cond (ppb) = 8.18E-03 ' 

** ***************************