March 8, 2012 MEMORANDUM UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON D.C., 20460 OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION SUBJECT: Drinking Water Assessment to Support First Fenazaquin (4-tert-butylphenethyl quinazolin-4-yl ether) Use on Food Crops PC Code: 044501; DP Barcode: 394030

; DECl **~**r 0 N : 444 :ZOO TO: FROM: EXECUTIVE SUMMARY The registrant (Gowen) is seeking registration of the first food uses of fenazaquin [GWN-1708F) for control of mites and white flies on crops. The food crops include alfalfa, avocado, beans dry, beans succulent, berry crop group, citrus crop group, field and sweet com, cotton, cucurbits, fruiting vegetables, grapes, hops, mint, pome fruit crop group, stonefruit crop group, strawberries, and tree nut crop group. The proposed new use requests ground, aerial, or chemigation spray applications of fenazaquin at a single maximum seasonal application rate of 0.45 lb ail A. The drinking water assessment was conducted using the total toxic residue (TTR) approach. The residues considered in this assessment include fenazaquin (parent),4-(2-(4-(1,1- imethylethyl)phenyl)ethoxy)quinazolone (Metabolite 1), and 2- Methyl- 2-( 4- { 2-[ (2-oxo-1,2- dihydroquinazolin-4-yl)oxy]ethyl }phenyl) propanoic acid (Metabolite 2) (HED ROCKS, 2/23/12).Tier I surface modeling predicts the fenazaquin residues concentrations to be 18.24 J.tg/L for the daily peak and 3.33 J.tg/L for the annual average.Based onTier II surface water modeling, the concentration of fenazaquin residues arenot expected to exceed 10.27 J.tg/L for a 1 in10 year daily peak, 3.82 J.tg/L for 1 in 10 yearannual average,and 3.05 J.tg/L for the 30 yearannual average.Tier I ground water modeling indicates the fenazaquin residue concentrations arenot expected to exceed 0.0704 J.tg/L for peak and long-term average concentrations. No monitoring .data areavailable to assess fenazaquin concentrations in ground and surface waters. PROBLEM FORMULATION Fenazaquin
is aninsecticide with amitochondrial electron transport (METI) mode of action. The chemical structure of fenazaquin and its degradation products are provided in Figures 1 and 2. Chemical identification and physical chemical properties of fenazaquin are provided in Table 1. Figure 1. Chemical Structure of Fenazaquin Structure of Metabolite

1 Structure of Metabolite

2 Figure 2. Chemical Structure of Fenazaquin Degradation Products 2Table 1. Chemical Identification Information for Fenazaquin. €h«tmical nam:e **l!ro~l\b**

**,** - Chemical Abstract Service number 120928-09-8 Empirical Formula C2oH22N20 Molecular weight 306.41 glmol Aqueous Solubility
0.102 mg!L Vapor Pressure (25°C) 7.2E-7 torr Octanol-water partition coefficient (log Kow) 5.7 Use Characterization The registrant (Gowen) is seeking registration for **f~od**usesof fenazaquin [GWN-1708F] for control of mites and white flyonalfalfa, avocado, beans dry, beans succulent, berry crop group, citrus crop group,field and sweet com,cotton, cucurbits, fruiting vegetables, grapes, hops, mint, pomefruit crop group,stonefruit crop group,strawberries, and treenut crop group.The proposed newuse requests ground, aerial, or chemigation spray applications of fenazaquin atasingle maximum seasonal application rateof 0.45lbailA. Table2 provides

a summaryofthe proposed newusesof fenazaquin.

3Table 2: Proposed New Uses for Fenazaqum Crop/Site alfalfa, avocado, beans dry, beans succulent, berry crop group, citrus crop group, field and sweet com, cotton, cucurbits, fruiting vegetables, grapes, hops, mint, pome fruit crop group, stonefruit crop group, strawberries, and tree nut crop group Application Type! Method Ground/ AeriaV Chemigation Environmental Fate Assessment Single Application Rate Range (lba.iJA) 0.45 Maximum Application Rate Per Season (lba.iJA) 0.45 Maximum Application Number Fenazaquin is persistent and immobile in terrestrial and aquatic environments. Major routes of dissipation include acid catalyzed hydrolysis, microbial-mediated degradation, erosion, and spray drift. The half-life for fenazaquin ranged from 51 to 123.8 days in aerobic soil and 58.7 to 133.3 days in aerobic aquatic environments. The half-life of fenazaquin total toxic residues ranged from 73 to 197 days in aerobic soil metabolism studies, and 65 to 291 days in aerobic aquatic environments. Degradation products of fenazaquin can be classified according to their formation by cleavage of the ether (ethoxy) linkage. This cleavage generates products with only the ter-butylphenyl group or the quinazoline group. The quinazoline products form mostly 4- quinazolinol and 2,4-quinazoline-diol. Linkage intact products are reactions involving the quinazoline part of the molecule. Major degradation products(> 10% of applied radioactivity) of fenazaquin are 4-(2-(4-(1,1-imethylethyl)phenyl)ethoxy)quinazolone (Metabolite 1), and 2- Methyl-2-(4-{2-[(2-oxo-1,2-dihydroquinazolin-4-yl)oxy]ethyl}phenyl) propanoic acid (Metabolite 2). Organic carbon sorption coefficients of fenazaquin range from 15,800 in sand and sandy loam soils to 101,083 in clay loam soil. Because fenazaquin has a low vapor pressure (7.2E-7 torr), volatilization

is not expected to be a route of dissipation for fenazaquin. Field dissipation studies conducted on soils in Germany and Italy showed half-lives from 11-44 days. Although degradation products were not identified in the field studies, the route of dissipation appeared to be associated with degradation, due to lack of leaching of fenazaquin. The bioaccumulation factor for fenazaquin ranged from 390 to 1400, depending on the exposure time and exposure concentration. Although fenazaquin has the potential to bioaccumulate, depuration of fenazaquin was rapid.

4Conceptual Model Fenazaquin applications canlead tosurface watercontamination through spraydrift and erosion of residue-bound sediment. Because fenazaquin is moderately persistent insoil withahigh soil sorption coefficient,

itisnot expected to significantly leach into ground water.An illustration highlighting possible environmental dissipation routesis shown in Figure 3. Figure 3. Routes of Pesticide Dissipation in the Environment Analysis The modeling for fenazaquin and its degradation products wasconducted using atotal residue approach. TierI groundwater estimated drinking waterconcentrations (EDWCs) were calculated using SCI-GROW **(~creening**Concentration in Groundwater, version 2.3, August 8, 2003. TierIIsurface waterEDWCs werecalculated using PRZM **~esticide**Root Zone Model, version 3.12.3, June 2006) and EXAMS (EXposure Analysis Modeling **~ystem,**version 2.98

.04

.06, April2005) models inthe PES shell

.All TierIIsurface water modeling was corrected for default percent cropped area(PCA) of 0.87

.For additional details onthe modeling, refer to http://www.epa.gov/pesticides/science/models

pg

.htm#aquatic

. 5Surface Water The scenario selection was based on the representative crops and geographic distribution of crops in the United States (Table 3). Pesticide application dates were assumed to occur a month before the maturation date for each PRZM scenario. Pesticide application conditions (i.e

. , method, rate, application interval) were taken from Table 2. The chemical input parameters for fenazaquin and its degradation product are shown in Table 4. Tier I FIRST PCA corrected EDWCs are shown in Table 5. Tier II PRZM/EXAMS PCA corrected EDWCs are shown in Tables 6 and 7. T bl 3 R

t f PRZMJEXAMS Sta d d S

p dC a e

0 epresen a 1ve

n ar cenanos or ro_p_ose ropso 0 Crop Type/Crop Grouping Representative Crop Scenarios Alfalfa

CA alfalfa, MN alfalfa Avocado

CA avocado, FL avocado Bean

MI bean, OR bean Berry Group
OR berries, Corn

IL corn, MN corn, OH corn, MS corn, ND corn, KS corn, lA corn, IN corn Cotton

CA cotton, NC cotton, MS cotton Fruiting Vegetables
PA veg NMC, CA fruit Grapes

CA grapes, NY grapes Hops

OR hops Citrus

FL citrus, CA citrus Mint

OR mint PomeFruit

PA apples, OR apples, NC apples Stone Fruit

MI cherries, GA peach Strawberries

CA strawberries, FL strawberries, Tree Nut

GA Pecans, CA almonds 6Table 4: Input Parameters Usedin FIRST, PRZM-EXAMS, SCIGROW Modeling to Estimate Total Toxic Residue Concentration (Parent, Metabolite 1,and M tbrt 2)fF

'eao1e

0 enazagum.

··•**,..~·.**r

**·~** Input Parameter

-':'Value

.JSource

' Molecular Weight 306.41 g/mole (parent) Calculated Water Solubility

0.1mgiL (parent) Product Chemistry Vapor Pressure

7.2x10"7 Torr (parent)Product Chemistry Hydrolysis

130 days (parent) MRID 47168704 Aqueous Photolysis

31 days (parent) MRID 47097610 Aerobic Soil Metabolism 151.7 days\ MRID 47168705 (mean

t 112+ (t 90xs)/n112 ) MRID 48167601 Aerobic Aquatic Metabolism 249.5 days\ (mean

t 112+ (t 90xs)/n112 ) MRID 48167601 Anaerobic Aquatic Metabolism Stable MRID 45854821 Mobility

815 mUgKoc KOCWIN v2.001 (Metabolite 2) 1-Because Metabolite

2hasa carboxyhc actd funcuonal group,ttwill be toruzed mmostenvlTOnrnental medta and, therefore, moremobile than fenazaquin

.Therefore, the Kocfor Metabolite

2wasestimated using KOCWINv2.00. Table S:TierIFIRST PCA1 corrected Estimated Drinking Concentrations for Fenazaquin and Its D d' Pd 'Sf: S We2ra ationrouctsmuraceourceater Application MethodAcute Chronic **~** Ground 17.74 3.11 Aerial

18
.24 3.33 1 PCA=0.87

7Table 6: Tier II PRZMIEXAMS PCA 1 corrected Estimated Drinking Concentrations for Fenazaquin and Its Degradation Products in Surface Source Water from Aerial Spray A r r •PPl tea tons

1 in 10 year Concentration

30 year Annual Scenario (p:VL> Average Peak Annual Average (pgiL) CA alfalfa 7.21 3.82 3.05 MN alfalfa 10.27 3.55 2.83 CA avocado 5.14 1.11 1.03 FLavocado 2.75 0.64 0.50 Mlbean 8.50 2.16 1.64 OR bean 5.22 1.66 1.33 OR berries 3.13 1.13 0.89 ILcorn 14.06 2.77 1.91 MNcorn 6.77 1.81 1.31 OHcorn 13.04 2.85 1.82 MS corn 15.37 3.09 1.85 NDcorn 4.96 1.54 1.26 KS corn 18.09 3.48 2.36 lA corn 12.57 2.16 1.36 IN corn 10.36 1.86 1.44 PA vegetables 9.57 2.48 1.67 CA fruit 4.16 0.91 0.71 CAgrapes 6.08 1.58 0.95 NY grapes 5.99 1.66 1.14 OR hops 6.91 1.80 1.24 FLcitrus 8.94 1.72 1.08 CAcitrus 2.83 0.85 0.66 OR mint 2.81 0.91 0.71 PAapples 5.20 1.30 0.97 OR apples 3.18 0.90 0.82 NC apples 7.75 1.37 0.88 Mlcherries 5.74 2.09 1.33 GA peach 4.81 0.92 0.61 CA strawberries 4.51 1.35 0.97 FL strawberries 9.99 1.57 0.99 GApecan 8.54 1.25 0.91 CAalmond 3.88 1.16 0.97 MS Cotton 15.71 2.56 1.73 NC Cotton 11.10 2.59 2.01 1 PCA=0.87

8Table 7:TierII PRZMIEXAMS PCA1 corrected Estimated Drinking Concentrations for Fenazaquin and Its Degradation Products in Surface Source Water from Ground Spray A li ffF

.•PPlcaIOns 0enaza( um

1 in10 yearConcentration

30 yearAnnual Scenario (PIVL) Average Peak Annual Average (pg/L) CA alfalfa 5.95

2.73 2.22 MN alfalfa 8.86

2.52 1.86 CA avocado 3.92

0.83

0.74 FLavocado 1.31

0.38

0.25 MIbean 8.52 1.99 1.46 OR bean 4.83 1.42 1.07 OR berries

2.82

0.88 0.64 ILcom 13.97

2.70 1.75 MNcom 5.94 1.64 1.12 OHcom 12.73

2.72 1.65 MScom 15.67 3.06 1.77 NDcorn 4.86 1.30 1.00 KScom 17.75 3.42

2.25 !Acorn 12.11 1.98 1.15 INcorn10.63 2.14 1.30 PA vegetables

8.72

2.29 1.47 CAfruit 2.64 0.60 0.38 CAgrapes 4.97 1.28 0.62 NY grapes5.99 1.66 1.14 OR hops 6.65 1.62 1.02 FLcitrus

8.93 1.63 0.97 CA citrus 2.08 0.49

0.33 OR mint 2.08 0.67 0.44 PAapples 4.51 1.06 0.73 OR apples 2.34 0.65 0.57 NC apples 6.89 1.17

0.66 Mlcherries 5.34 1.85 1.05 GApeach 3.71

0.67

0.35 CA strawberries

4.62 1.18 0.79 FL strawberries

9.77 1.42

0.80 GA pecan8.05 1.13 0.72 CAalmond 3.88 0.93 0.74 MS Cotton 15.01 2.50 1.63 NC Cotton 10.54

2.50 1.89 1PCA=0.87

9Groundwater The chemical input parameters for fenazaquin and its degradation products are shown in Tables 2 and 5. The Tier 1 SCI-GROW EDWCs are shown in Table 8. Table 8: Tier I SCI-GROW Estimated Drinking Concentrations for Total Toxic Residues of Fenazaquin in Ground Source Water from Fenazaquin Residues Application Application EDWC Rate Number (ugiL) lbai/A Fenazaquin Residues

1 0.45

1 0.0704 1- Parent, Metabolite
1, and Metabolite

2 Monitoring Data There are no water monitoring data for fenazaquin in USGS National Water-Quality Assessment Program (NA WQA), USEP A/USGS Pilot Reservoir Monitoring Program, USDA Pesticide Data Program (PDP), and California Department of Pesticide Regulation (CDPR). 10