OFFICE OF CHEMICAL SAFETY AND POLLUTION PREVENTION **UNITED ST AT**  **ES ENVIRONMENT AL**  **PROTECTION A GENCY** 

WA SHINGTON, D.C. 20460



### MEMORANDUM **DATE:** August 11, 2010 **SUBJECT:** Tier I Estimated Environmental Concentrations of Bifenthrin for the Use in the

Human Health Risk Assessment ; IR
- 4 Petition for the Use of the Chemical on Grass, Forage and Hay (PC Code 128825; DP Barcod e D372556) **TO:** Laura Nollen , Risk Manager Reviewer

Barbara Madden, Review Manager #05 Daniel (Dan) Rosenblatt **,** Chief Minor Use Branch Registration Division (7505P) **and :**  William Irvin , Risk Assessor

Jack Arthur , Chief Registration Action Branc h V Health Effects Division (7509P) **FROM:** José Luis Meléndez, Chemist

Environmental Risk Branch V Environmental Fate and Effects Division (7507P) **THROUGH:** Mah T. Shamim, Ph.D., Chief

Environmental Risk Branch V Environmental Fate and Effects Divi sion (7507P) This memo presents the Tier I Estimated Surface Drinking Water Concentrations and Estimated Ground Water Concentrations (EDWCs) for b ifenthrin, calculated using the Tier I aquatic models FIRST and SCI

- GROW, respectivel y, for use in the human health risk assessment. The registrant is proposing the uses on grass, forage and hay

. Based on an inspection of the new uses of bifenthrin, it was found that lettuce still represents the scenario with the highest EDWCs , and, therefore, the drinking wate rs assessment results do not change from the previous ones

. For electronic cop y of the last assessment see **A ttach**  **ment A**
. The Estimated Drinking Water Concentrations (EDWCs) for bifenthrin were calculated based on a maximum application rate of 0.5 lb a.i. /A/season. The acute drinking water concentration in2



### surface water is 14.0 ppt of bifenthrin, based on applications of the chemical to lettuce. The cancer/ chronic drinking water concentration is 14.0 ppt (based on applications of lettuce, with the highe st application rate and PCA). The SCI

- GROW generated EDWC is 3.00 ppt of bifenthrin, which is recommended for use, both for acute and chronic exposures. Because of the very low solubility

of bifenthrin, the EDWCs did not exceed 14.0 ppt (the solubility o f bifenthrin). Should there be a need for additional refinements, the EFED can perform a Tier II aquatic assessment, for surface waters. **Table 1. Maximum Tier I Estimated Drinking Water Concentrations (EDWCs) for drinking water risk assessment based on**  **aerial application of bifenthrin on lettuce. DRINKING WATER SOURCE**  **(MODEL USED) USE (rate modeled)**  **MAXIMUM ESTIMATED DRINKING WA TER**  **CONCENTRATION (EDWC) ( ppt )**  Groundwater ( SCI
- GROW ) Lettuce (0. 5 lb. a.i./A/season ) Ac ute and Chronic 3.00 Surface wat er (FIRST) Lettuce (0. 5 lb. a.i./A/season ) Ac ute 14.0 Lettuce (0. 5 lb. a.i./A/season ) Chronic 14.0 

### Use Characterization Table 2 provides a summary of the new use proposed in this action for bifenthrin . The use information was obtained from the proposed supplemental label s for Brigade 2EC Insecticide/ Miticide and Brigade WSB Insecticide/ Miticide. **Table 2. S**  **ummary of**  **new use s**  **for bifenthrin, based on the proposed supplemental label**  **s for**  **Brigade 2EC Insce**  **ticide/ Miticide (EPA Reg. No. 279 -**  **3313 )**  **and Brigade WSB Insecticide/ Miticide (EPA Reg. No. 279 -**  **3108) .** 

**USE SINGLE**  **APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inch es)**  **PHI** Grass Forage, Fodder, and Hay Group and Grass Grown for Seed, Pasture and Rangeland (including bahiagrass, barnyardgrass, bentgrass, Bermudagrass, Kentucky bluegrass, big blue a ste m , smooth bromegrass, buffalograss, reed canarygrass, centipedegrass , crabgrass, cupgrass, dallisgrass, sand dropseed, Kentucky fescue, meadow foxtail, eastern gramagrass, side

- oats grama, guinea grass, I

ndian grass, Johnsongrass, lovegrass, napiergrass, oatgrass, orchardgrass, pangolagrass, paspalum, redtop, I

talian ryegr ass, St. Augustine grass, sprangletop, squirreltailgrass, stargrass, switchgrass, timothy, crested wheatgrass, wildrye grass and zoysia grass. Also included are sudangrass and sorghum forages and their hybrids. ) 0.033
- 0.20 Not

specified 0.2 14 G or A 0 30 for forage and hay3 

### A **ttachment A :**  **PREVIOUS DWA FOR BIFENTHRIN** 
**UNITED STA**

**TES ENVIRONMENTA L PROTECTION A**  **GENCY WA** **SHINGTON D.C., 20460**

**OFFICE OF PREVENTION, PESTICIDES AND**  **TOXIC SUBSTANCES** PC Code 128825 DP Barcode D334155, D334162,

D334166, D334169 

### MEMORANDUM **DATE:** February

7, 2007 **SUBJECT:** Tier I Estimated Environmental Concentrations of Bifenthrin for the Use in the

Human Health Risk Assessment ; IR
- 4 Petition for the Use of the Chemical on Vegetable Roots (except for sugar beet and garden beet, Subgroup 1B) , Beets, Radish, Pistachio, Peanuts, Soy bean, Fruiting Vegetables (Subgroup 8), and May haw **TO:** Shaja Brothers, Risk Manager Reviewer

Daniel Rosenblatt, Chief Barbara Madden, Chief Minor Use Branch Registration Division (7505P) **AND:** PV Shaw, Chi ef

Registration Action Branch I Health Effects Division (7509P) **FROM:** José Luis Meléndez, Chemist

Environmental Risk Branch V Environmental Fate and Effects Division (7507P) **THROUGH:** Mah T. Shamim, Ph.D., Chief

Environmental Risk Branch V Envir onmental Fate and Effects Division (7507P) This memo presents the Tier I Estimated Surface Drinking Water Concentrations and Estimated Ground Water Concentrations (EDWCs) for Bifenthrin, calculated using the Tier I aquatic models FIRST and SCI

- GROW, respe ctivel y, for use in the human health risk assessment. Based on an inspection of all the uses of bifenthrin, it was found that lettuce is still the use with the major exposure and the highest PCA , and, therefore, the drinking waters assessment results do n ot change from the previous ones . An electronic copy of the previous assessment is attached.4



### The Estimated Drinking Water Concentrations (EDWCs) for bifenthrin were calculated based on a maximum application rate of 0.5 lb a.i./A/season. The acute drinkin g water concentration in surface water is 0.0140 ppb of bifenthrin, based on applications of the chemical to lettuce. The cancer/chronic drinking water concentration is 0.0140 ppb (based on applications of lettuce, with the highest application rate and PC A). The SCI

- GROW generated EDWC is 0.00300 ppb of bifenthrin, which is recommended for use, both for acute and chronic exposures. Because of the very low solubility

of bifenthrin, the EDWCs did not exceed 0.0140 ppb ( that is, the solubility of bifenthrin ). Table 1 provides a summary of the Tier I modeled drinking water concentrations. Should there be a need for additional refinements, the EFED can perform a Tier II aquatic assessment, for surface waters. **Table 1. Maximum Tier I Estimated Drinking Wate r Concentrations (EDWCs) for drinking water**  **risk assessment based on aerial application of bifenthrin on lettuce. DRINKING WATER SOURCE**  **(MODEL USED) USE (rate modeled)**  **MAXIMUM ESTIMATED DRINKING WATER CONCENTRATION (EDWC) ( ppb)**  Groundwater ( SCI
- GROW ) Lettuce (0. 5 lb. a.i./A/season ) Ac ute and Chronic 0.00300 Surface water (FIRST) Lettuce (0. 5 lb. a.i./A/season ) Ac ute 0.0140 Lettuce (0. 5 lb. a.i./A/season ) Chronic 0.0140 

### Use Characterization Table 2 is an updated summary of all agricultural use patterns for bifenthrin. The highlighted uses are those proposed new ones. The use information was obtained from the proposed label s for Capture 2EC Insecticide/ Miticide , Brigade WSB Insecticide/ Miticide and Capture 1.15G Insect icide/ Miticide. **Table 2. Updated summary use information for bifenthrin, based on the proposed labels for Capture 2EC Insecticide/ Miticide (EPA Reg. No. 279**  **- 3069), Brigade WSB Insecticide/ Miticide**  **(EPA Reg. No. 279 -**  **3108) and Capt ure 1.15G Insecticide/ Miticide (EPA Reg. No. 279**  **- 3244).**  **USE SINGLE** 

**APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inches) PHI** 

Cotton * 0.1 5 0.5 3 Ground, aerial or ULV 0 14

Field corn (grain and silage), popcorn, field corn grown for seed

- at plant use 0.08 Not specified 0.1 Not specified In furrow 0 N/A5



### Table 2. Updated summary use information for bifenthrin, based on the proposed labels for **Capture 2EC Insecticide/ Miticide (EPA Reg. No. 279 -**  **3069), Brigade WSB Insecticide/ Miticide (EPA Reg. No. 279**  **- 3108) and Capt**  **ure 1.15G Insecticide/ Miticide (EPA Reg. No. 279 -**  **3244). USE**  **SINGLE**

**APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inches) PHI** 

Field corn (grain and silage), popcorn, field corn grown for seed

- pre emergence (PRE) or pre - plant inco rporated (PPI) 0.062 0.040 1 0.062 0.040 N/A PPI PRE PPI
- not

deeper than 3 in. PRE
- not specified N/A

Field corn (grain and silage), popcorn, field corn grown for seed 0.1 3 0.3 including at plant, PPI and PRE Not

speci fied Ground or

aerial 0 30

Sweet corn, sweet corn grown for seed

at plant use 0.08
- 0.1 Not specified 0.1 Not specified In furrow ;

granules must be incorporat ed into the top 1” 0
- 1” N/A

Sweet corn, sweet corn grown for seed 0.1 2 0.2 Not specified Ground or

aerial 0 1; 18 for corn that is hand harves

ted Succulent peas and beans : Pea (

Pisum spp. ) dwarf pea, edible

- pod pea, English pea, garden pea, green pea, snow pea, sugar snap pea , Pigeon pea Bean (Phaseolus spp. ) broadbean (succulent), lima bean (green), runner bean, snap bean, wax bean Bean ( Vigna spp. ) asparagus bean, blackeyed pea, Chinese longbean, cowpea, mothpea, Southern pea, yardlong pea Jackbean Soybean (immature seed) Sword bean 0.1 2 0.2 Not specified Ground or

aerial May be applied in furrow with the seed or transplant for fireworm 0 3, 9 for peas/ beans that are hand harves

ted6



### Table 2. Updated summary use information for bifenthrin, based on the proposed labels for **Capture 2EC Insecticide/ Miticide (EPA Reg. No. 279 -**  **3069), Brigade WSB Insecticide/ Miticide (EPA Reg. No. 279**  **- 3108) and Capt**  **ure 1.15G Insecticide/ Miticide (EPA Reg. No. 279 -**  **3244). USE**  **SINGLE**

**APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inches) PHI** 

Dried shelled peas and beans : bean (Lupinus); bean (Phaseoulus) field, kidney, lima, navy, pinto, tepary; bean (Vigna) adzuki, blackeyed, catjang, c owpea, crowder pea, moth, mung, rice, southern, urd; broad bean (dry); chickpea; guar; lablab bean; lentil; pea (Piscum), field pea; pigeon pea 0.1 2 0.2 Not specified Ground or

aerial 0 14

Head and Stem Brassica Vegetables including: broccoli, Chinese br occoli, Brussels sprouts, cauliflower, cavalo broccolo, kohlrabi, cabbage, Chinese cabbage (napa), Chinese mustard cabbage (gai choy) 0.1 5 0.5 7 Ground or aerial 0 7

Canola, Crambe, Rapeseed 0.04 2 0.08 14 Ground or aerial 0 35
Cucurbits : chayote, citro n melon, cucumber, gherkin, edible ghourd (various), muskmelon (various, for example cantaloupe and pineapple melon), pumpkin, summer squash (various), winter squash (various), watermelon (includes hybrids) 0.1 3 0.3 7 Ground or aerial 0 3

Lettuce , head 0 .1 5 0.5 7 Ground or aerial 0 77



### Table 2. Updated summary use information for bifenthrin, based on the proposed labels for **Capture 2EC Insecticide/ Miticide (EPA Reg. No. 279 -**  **3069), Brigade WSB Insecticide/ Miticide (EPA Reg. No. 279**  **- 3108) and Capt**  **ure 1.15G Insecticide/ Miticide (EPA Reg. No. 279 -**  **3244). USE**  **SINGLE**

**APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inches) PHI** 

Caneberries including blackberriesbingleber rie dewberries lowberries marion

berries olallie

- berries young - berries loganberrie raspberries 0.1 2 0.2 One pre
bloom and one post bloom Ground or

aerial 0 3

Artichoke 0.1 5 0.5 15 Ground or aerial 0 5 Hops * 0.1 3 0.3 21 Ground or aerial 0 14
Pears 0.2 ~2.5 0.5 30 Ground or aerial 0 14 Eggplant 0.1 2 0.2 9 Ground or aerial 0 9
Citrus 0.25
0.5 2

1 0.5

0.5 Early and

late season N/A Ground

Ground 0

0 1

1 Spinach 0.1 4 0.4 7 Ground or aerial 0 40 Grapes 0.1 1 0.1 N/A Ground or aerial 0 30 Leafy Brassica Greens : broccoli raab, bok choy, collards, kale, mizuna, mustard greens, mustard spinach, rape greens 0.1 4 0.4 7 Ground or aerial 0 7

Tuberous and corm vegetables : potato , sweet potato, arracacha, arrowroot, Chinese artichoke, Jerusalem artichoke, edible canna, cassava, chufa, dasheen, ginger, leren, tanier, turmer, yam bean, true yam 0.3 in

furrow at planting; 0.15 as lay

- by ; and 0.1 foliar nmt 2

foliar applicatio ns 0.5

including soil applications 21 for

foliar applications In furrow ,

lay

- by and foliar treatments 0 218



### Table 2. Updated summary use information for bifenthrin, based on the proposed labels for **Capture 2EC Insecticide/ Miticide (EPA Reg. No. 279 -**  **3069), Brigade WSB Insecticide/ Miticide (EPA Reg. No. 279**  **- 3108) and Capt**  **ure 1.15G Insecticide/ Miticide (EPA Reg. No. 279 -**  **3244). USE**  **SINGLE**

**APP. RATE (lb a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lb a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPO**  ****

**RATION DEPTH**  **(inches) PHI** 

Cilantro (coriander) 0.1 5 0.5 7 Ground or aerial 0 3
Okra 0.1 2 0.2 7 Ground or aerial 0 7
Strawberries 0.2 ~2.5 0.5 7 Ground or aerial 0 0
Tre e nut crop : almond , beech nut, Brazil nut, Butternut, cashew, chestnut, chinquapin, filbert (hazelnut), hickory nut, macadamia nut (bush nut), **pistachio** , walnut (black and English) 0.2 ~2.5 0.5 15 Ground or aerial 0 7 (21 for pecans)

Root Crops : carrots , celeriac, turnip rooted chervil, chicory, ginseng, horseradish, turnip rooted parsley, parsnip, **radish** , oriental radish, rutabaga, salsify, black salsify, Spanish salsify, skirret, turnip (0.006 lb

ai/linear ft)

0.1 1 in

furrow application at planting 5 0.5 7 In Furrow and Foliar

0 21
**Root Crops :**  **Garden Beets** 0.1 4 0.4 7 Foliar 0 1 **Soybeans** 0.1 3 0.3 30 Foliar 0 18 **Fruiting Vegetables**  **: Eggplant, pepper (bell**  **and non -**  **bell), groundcherry pepino**  0.1 2 0.2 7 Ground or aerial 0 7

**Fruiting Veget**  **ables :**  **tomato , tomatillo**  0.1 4 0.4 10 Ground or aerial 0 1

**Peanut** 0.1 5 0.5 14 Foliar 0 14 **Mayhaw** 0.1 2 0.2 7 Foliar 0 30 *Not for use in California.9 

### UNITED STA

**TES ENVIRONMENTA L PROTECTION A**  **GENCY WA** **SHINGTON D.C., 20460**

**OFFICE OF PREVENTION, PESTICIDES AND**  **TOXIC SUBSTANCES** 

# COPY PC Code 128825 DP Barcode D 311012 **MEMORANDUM DATE:**  February

7 , 200 6 **SUBJECT:** Tier I Estimated Environmental Concentrations of Bifenthrin for the Use in the

Human Health Risk Assessment. **TO:** Shaja Brothers, Risk Manager Reviewer

Sidney Jackso n , Risk Manager Reviewer BeWanda Alexander, Risk Manager Reviewer Daniel Rosenblatt, Risk Manager #5 George LaRocca, Risk Manager #13 Registration Division (7505C) **AND:** Karen Whitby , Branch Chief

Registration Action Branch I Health Effects Di vision (7509C) **FROM:** José Luis Meléndez, Chemist

E RB V , Environmental Fate and Effects Division (7507C) **THROUGH:** Jean Holmes, DVM, Acting Chief

Environmental Risk Branch V Environmental Fate and Effects Division (7507C) This memo presents the Tier I Estimated Surface Drinking Water Concentrations and Estimated Ground Water Concentrations (EDWCs) for Bifenthrin , calculated using the Tier I aquatic models FIRST and SCI
- GROW , respectivel y, for use in the human health risk assessment. The Estimated Drink ing Water Concentrations (EDWCs) for bifenthrin were calculated based on a maximum application rate of 0.5 lb a.i./A/season. The acute drinking water concentration in10



### surface water is 0.0140 ppb of bifenthrin, based on applications of the chemical to lettu ce . The cancer/chronic drinking water concentration is 0.0140 ppb (based on applications of lettuce , highest application rate). The SCI
- GROW generated EDWC is 0.00300 ppb of bifenthrin , which is recommended for use, both for acute and chronic exposures. Because of the very low solubility of bifenthrin, the EDWCs did not exceed 0.0140 ppb (the solubility of bifenthrin). Table 1 provides a summary of the Tier I modeled drinking water concentrations. Should there be a need for additional refinements, the E FED can perform a Tier II aquatic assessment, for surface waters. **EXECUTIVE SUMMARY** Bifenthrin (chemical name 2
- methylbiphenyl

- 3
- yl methyl (Z )

- (1 RS,3 RS

)

- 3
- (2

- chloro

- 3,3,3
- trifluoroprop

- 1
- en yl )

- 2,2
- dimethylcyclopropanecarboxylate , CAS # 82657
- 04
- 03, PC code 128825) is a sy

nthetic pyrethroid insecticide . Its structure has three rings, two phenyl rings attached to each other b y a single bond, and a cyclopropyl ring. The chemistry of bifenthrin may be dictated b y it s ester moiety ; however, laboratory studies show that it is relatively stable. The molecule has some chiral centers, and a double bond that brings isomer possibilities. Bifenthrin is a neural toxic insecticide acting through direct contact and ingestion, having a slight repellent effect. The primary biological effects of bifenthrin and other p yr ethroids on insects and vertebrates reflect an inhibition of the correct firing of neurotransmitter deliver signals from one cell to another via nerve membrane inhibition of the voltage

- gated Ca2+ 

### channels coupled with a stimulatory

effect on the voltage

- gated Na+ 

### channels (sodium ion channels) . All py rethroids act as axonic poisons, affecting both the peripheral and central nervous s ys tems, and share similar modes of action. Py

rethroids, including bifenthrin, stimulate repetitive action in the nervous sy stem by binding to voltage

- gated sodium channels, prolonging the sodium ion permeability during the excitatory

phase of the action potential. This action leads to spontaneous depolarizations, augmented neurotransmitter secretion rate and neuromuscular block, which ultimately

results in paraly sis of the insect. This is a Tie r I s creening assessment using Tier 1 aquatic models SCI
- GROW and FIRS T , and maximum application rates for bifenthrin, with minimum application intervals

. Itwas found that the worse case scenario was lettuce for bifenthrin, with the highest application rate, and the highest PCA. There are no major degradates for bifenthri n; therefore, no degradates were modeled in this assessment. The major uncertainty with respect to this assessment appears to be the problem with the extremely low solubility

of bifenthrin. The hydrol ys is, aqueous photoly sis and batch equilibrium studies were performed in the presence of unusually high concentrations of acetonitrile. The proposed uses involved in this action are the following IR4 tolerance petitions: leafy brassica greens, tuberous and corm vegetables, dried shelled peas and beans, ci lantro and okra, and an application to amend the label to include tobacco (refer to highlighted section of Table 2).11



### Table 1. Maximum Tier I Estimated Drinking Water Concentrations (EDWCs) for **drinking water risk assessment based on aerial application o f**  **bifenthrin on lettuce .**  **DRINKING WATER SOURCE (MODEL USED)**  **USE (rate modeled) MAXIMUM ESTIMATED DRINKING WATER**  **CONCENTRATION (EDWC) ( ppb)** Groundwater ( SCI
- GROW ) Lettuce (0. 5 lb. a.i./A/season ) Ac ute and Chronic 0.00300 Surface water (FIRST) Lettuc e (0. 5 lb. a.i./A/season ) Ac ute 0.0140 Lettuce (0. 5 lb. a.i./A/season ) Chronic 0.0140 

### PROBLEM FORMULATION This is a Tier I drinking water assessment that uses modeling and available monitoring data to estimate the groundwater and surface water concentrations in drinking water source water (pre

treatment) resulting from pesticide use on sites that are highly vulnerable. This initial tier screens out chemicals with low potential risk and allows OPP to focus resources on more ref ined risk assessments for chemicals which potentially present more significant risks. This drinking water assessment will report potential exposure concentrations for the human health dietary risk assessment and provide a clear and transparent description of how those concentrations were determined. **ANALYSIS Use Characterization**  Table 2 is a summary

of all agricultural use patterns for bifenthrin. The highlighted uses are those proposed new ones. The use information was obtained from the current label for Capture 2EC Insecticide/Miticide and the proposed labels for the same product. **Table 2. Summary use information for bifenthrin**  **, based on Capture 2EC**  **Insecticide/Miticide label**  **(EPA Reg .**  **No. 279 -**  **3069) USE**  **SINGLE**

**APP. RATE (lbs. a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lbs. a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPORATION** 

**DEPTH (inches) PHI** 
Cotton 0.1 5 0.5 3 Ground or aerial 0 14
Corn 0.1 3 0.3 As necessary Ground or

aerial 0 30
Sweet co rn 0.1 2 0.2 As necessary Ground or

aerial 0 1
Succulent peas and beans 0.1 2 0.2 Not specified Ground or

aerial 0 3

Brassicas 0.1 5 0.5 7 Ground or aerial 0 712 **USE SINGLE** 

**APP. RATE (lbs. a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lbs. a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPORATION** 

**DEPTH (inches) PHI** 
Canola, Crambe, Rapeseed 0.04 2 0.08 14 Ground or aerial 0 35

Cucurbits 0.1 3 0.3 7 Ground o r aerial 0 3 Eggplant 0.1 2 0.2 7 Ground or aerial 0 7 Lettuce, head 0.1 5 0.5 7 Ground or aerial 0 7
Caneberrie s 0.1 2 0.2 One pre
bloom and one post bloom Ground or

aerial 0 3

Artichoke 0.1 Not specified 15 Ground or aerial 0 5 Peppers 0.1 2 0.2 7 G round or aerial 0 7 Hops 0.1 3 0.3 21 Ground or aerial 0 14
Pears 0.2 3 0.5 30 Ground or aerial 0 14
Citrus 0.25 2 0.5 Early and late season Ground 0 1
Tom atoes 0.08 4 0.32 10 Ground 0 1 Spinach 0.1 4 0.4 7 Ground or aerial 0 40 Grapes 0.1 1 0.1 N/A Ground or aerial 0 30 Leafy Brassica Greens 0.1 4 0.4 7 Ground or aerial 0 7

Tuberous and corm vegetables 0.3 in

furrow at planting and 0.1 foliar 3 0.5 21 Foliar treatment not specified 0 21

Dried shelled peas 0.1 2 0.2 Not specified Ground or

aerial 0 1413 **USE SINGLE** 

**APP. RATE (lbs. a.i./A)**  **NUMBER**

**OF APPS. SEASONAL** 

**APP. RATE (lbs. a.i./A)**  **INTERVAL**

**BETWEEN APPS. (days)**  **APP.**

**METHOD INCORPORATION** 

**DEPTH (inches) PHI** 
Dried shelled beans 0.1 3 0.3 Not specified Ground or

aerial 0 14

Tobacco 0.1 at

transplant, and 0.05 foliar Not specified 0 N/A

Cilantro (coriander) 0.1 5 0.5 7 Ground or aerial 0 3
Okra 0.1 2 0.2 7 Ground or aerial 0 7 

### Capture 2EC Insecticide/M iticide is an emulsifiable concentrate. It may be applied by

ground, air or ULV methods. The label imposes certain restrictions (buffer zones) to protect bodies of water, accordingl y: 25 ft for ground applications, 150 ft for aerial applications and 450 ft for ULV applications. There is also a granular formulation for use on corn at plant (granules are incorporated into the top one inch of the soil) or foliar (as granules). The use pattern selected for drinking water modeling was lettuce. It has the m aximum application rate (maximum number of applications) with the maximum PCA. **Fate and Transport Characterization** Table 3 provides a summary of the major ph ys ical, chemical, environmental fate and transport properties of bifenthrin. **Table 3. Summary of physical/chemical and environmental fate and transport properties of**  **bifenthrin .** 

**PARAMETER VALUE(S) (units)**  **SOURCE COMMENT**  Chemical Name 2
- methylbiphenyl

- 3
- ylmethyl (Z )

- (1 RS,3 RS )

- 3
- (2

- chloro

- 3,3,3
- trifluoroprop

- 1
- enyl)

- 2,2
- dime thylcyclopropanecarboxylate – IUPAC name

Molecular Weight 422.87 g/mol

– – Solubility (2 2 o C) 1.4x10 - 5 mg/L La skowski 2002

– Vapor Pressure (2 5 o C) 1.8 x 10 - 7 mmHg Tomlin, C. editor 1994

. – Henry’s Law constant 7.2 x 10 - 3 Atm - m 3 /mol - - Estimat ed from vapor pressure and water solubility. pKa (20 o C) NA
- - – Octanol

- Water Partition Coefficient (K OW ) 3.00x10 6 La skowski 2002

–14 **PARAMETER VALUE(S) (units)**  **SOURCE COMMENT**  Hydrolysis Half

- life [ pH 5, 7, 9; (25 o C) ] Stable ACC : 251728, MRID : 132539. Stable at all pHs. Aqueous Ph otolysis Half

- life Relatively stable ACC: 264642
. Samples were not buffered and contained 30% acetonitrile as cosolvent. Natural sunlight was used. Soil Photolysis Half

- life t 1/2 = 147 days and 98.5 days for

cyclopropyl and phenyl labels, respectivel y. Corrected half

- lives are 147 days and 106 days (no significant degradation in dark control for cyclopropyl label) ACC : 264642
. Natural sunlight in New Jersey, silt loam soil used.

Aerobic Soil Metabolism Half

- life (days) Soil Cyclopropy l Phenyl SL 132 115 SiL 250 156 SiCL 129 96.8 MRID : 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278
. - -

Anaerobic Soil Metabol ism Stable MRID: 264642
- - Anaerobic Aquatic Metabolism Half

- life NA
- - – Aerobic Aquatic Metabolism Half

- life NA
- - - - Organic Carbon Partition Coefficient (K

OC ) 131,000, 239,000, 302,000, 275,000

mL /g OC for the S, SL, SiL and SiC L, respectively MRID: 254401
. – Soil Partition Coefficient (K d ) 992, 4192, 5430, 3690 mL/g

for the S, SL, SiL and SiCL, respectively MRID: 254401
. – Terrestrial Field Dissipation Half

- life Site Half

- lives Champ aign, IL 192 days Fresco, CA 345 Madera, CA 155 Imperial County, CA 228 Tifton, GA 122 Marion, AR 78 Fresno, CA 193 Champaign, IL 118 Champaign, IL 126 Marion, AR 121 San Joaquin, Fresno DT 50 35 MRID: 264642, 42339203, 42339201, 42334167, 41673103, 41673101, 41671302
. - -

Aquatic Field Dissipation Half

- life Dallas County, Orville, Alabama Residues of bifenthrin were found in the sediments of the pond during the 12 months period after application; there was no discernable pattern of decay. MRID: 40981803, 40981805, 4098 1808, 40981812, 40981814, 40981815, 40981816, 40981817, 40981818, 40981819. - -



### Bifenthrin is a s ynthetic pyrethroid. Its structure has three rings, two phenyl rings attached to each other b y a single bond, and a cycloprop yl ring. The molecule has some chiral centers, and a double bond that bring isomer possibilities. According to the Capture 2EC Insecticide/Miticide label, a minimum of 97% consists of cis isomers (see figure in the Appendix ).15



### Studies conducted on bifenthrin indi cate that it is persistent under most conditions and bioaccumulative. It appears that a major route of degradation is aerobic metabolism. Bifenthrin is relatively stable to hydroly sis at all pH’s. Itis relatively stable to aqueous and soil photoly sis and degrades slowl y under both aerobic and anaerobic soil metabolism conditions (half

- life range 97
- 250 day s in 3 soils, and relativel y stable, respectivel y). Bifenthrin is relatively immobile in four soils tested (KOC 

### range 131,000 to 275,000 ). Field stu dies show a pattern consistent with the laboratory studies, with relatively

high persistence (half

- lives ranging from 78 to 345 day s in 10 field trials) and low mobility of the chemical in soil. In aquatic environments, it appears that residues of bifenthrin persist in pond sediments (and in the water column) for extended periods (at least 12 months of monitoring). No major metabolites were observed (>10% of the applied) in any of the laboratory

studies. The high octanol/ water partition coefficient sug gests that bifenthrin will bioconcentrate in aquatic organisms. Bifenthrin was highl y bioaccumulative in fish with slow depuration. The very low water solubility

and hydrophobic nature of bifenthrin leads to strong soil adsorption and a tendency to parti tion to sediment in aquatic s ys tems. Bifenthrin has a vapor pressure of 1.8x10 – 7 

### mmHg, water solubility of 0. 0 1 40 ppb, and an estimated Henry ’s law constant of 7.2x10 - 3 

### atm - m 3 

### /mol. Based upon its Henry ’s law constant and vapor pressure, bifenthrin is ex pected to have a moderate to low potential for volatilization from soil and water surfaces. Bifenthrin’s potential for volatilization is reduced significantl y because it adsorbs strongly to soils, suspended solids, sediment and organic matter in the water column. A laboratory

volatility study showed a maximum volatility at 40 ° C of 5.07x10 - 4 

### μg/cm 2 

### hr (average at 14 day s), a relativel y low value. Bifenthrin can be spray

applied by

ground or aerially

on agricultural settings. A buffer region is label recommended; however, under a high end drift scenario, substantial amounts of the chemical can reach adjacent bodies of water via spray drift. Furthermore , substantial fractions of the applied bifenthrin should be available for runoff for several weeks to seve ral months. Due to its low solubility

(0. 0 1 4 ppb) and high level of binding it appears that bifenthrin would remain bound to the soils during run

- off events, and that the chemical would reach surface waters if the run - off event is accompanied by erosion. Once bifenthrin reaches surface water, the fate of the chemical is of concern since bifenthrin is very toxic to fish and aquatic invertebrates. The Agency believes that bifenthrin, due to its high level of binding, would remain bound to the sediments and would dissolve only very slowly into the water column. Organisms that live near the sediments may

be particularly

at risk. The sediments may serve as reservoirs of bifenthrin, where it will persist. A supplemental aquatic field dissipation study emplo yi ng a site in Alabama showed that bifenthrin in aquatic environments (a pond) persists for extended periods of time. It was found throughout the 12 months of monitoring after the last pesticide application, that residues were observed in the water column and in the sediment , w ith no clear pattern of decline. On the other hand, b ifenthrin is not likely to reach subsurface soil environments or ground waters. Various terrestrial field dissipation studies confirm that bifenthrin remains mostly in the upper soil level.16



### Due to the slow dissipation pathway s for bifenthrin, no transformation products were observed to be higher than 10% of the applied in an y of the laboratory studies. The major uncertainties with respect to the environmental fate studies on bif enthrin are related to the extremely

low solubility

of bifenthrin and the problems found when the registrant performed these studies. The h ydrolysis, aqueous photol ys is, and batch equilibrium studies were performed in unusually

high concentrations of acet onitrile. The cosolvent may have had an effect on the results. Furthermore, the batch equilibrium studies were performed at a single concentration (a Freundlich isotherm was not developed). The EFED had to rel y on a single point result. Table 4 is a summary

of degradate formation for bifenthrin. Note that, because bifenthrin is relativel y stable or dissipates very slowl y in all studies, no major tr ansformation products ( ≥10% of the applied) were observed. **Table 4. Summary of degradate formation from degradation of bifenthrin**  **. STUDY TYPE**  **SOURCE DEGRADATE and MAXIMUM CONCENTRATION**  **DEG1 (% applied) DEG2 (% applied)**  **DEG3 (% applied)** Hydrolysis A CC : 251728, MRID : 132539. NO hydrolysis product exceeded 10% of the applied during the study. Aqueous Photolysis ACC: 264642
. NO aqueous photolysis product exceeded 10% of the applied during the study. Soil Photolysis ACC: 264642
.. NO soil photolysis product exceeded 10% of the applied during the study.
Aerobic Soil Metabolism MRID : 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278
. NO aerobic soil metabolism product exceeded 10% of the applied during the study.

Anaerobic Soil Metab olism

. MRID: 264642 NO anaerobic soil metabolism product exceeded 10% of the applied during the study. Aerobic Aquatic Metabolism

. NA
- - Anaerobic Aquatic Metabolism NA
- - Terrestrial Field Dissipation MRID: 40981803, 40981805, 40981808, 4098181 2, 40981814, 40981815, 40981816, 40981817, 40981818, 40981819. 4’
- OH
- Bifenthrin detected in certain studies.



### No degradates were considered “major” ( > 10% of applied in parent equivalents ), nor were they flagged for further quantitation. There is uncertainty with respect to the aqueous photoly sis study , which was conducted in the presence of 30% acetonitrile. Even though no substantial photoly sis was observed, it is not known if the cosolvent may have affected the formation of transformation products.17



### Drinking Water Exposure Modeling Models SCI
- GROW (Screening Concentration in Ground Water) is a regression model used as a screening tool for ground water used as drinking water. SCI

- GROW was developed by regressing the result s of Prospective Ground Water studies against the Relative Index of Leaching Potential (RILP). The RILP is a function of aerobic soil metabolism and the soil

water partition coefficient. The output of SCI

- GROW represents the concentrations that might be expected in shallow unconfined aquifers under sandy soils, which is representative of the ground water most vulnerable to pesticide contamination likely to serve as a drinking water source. ( **Ref. 2** ) FIRST (FQPA Index Reservoir Screening Tool) is a screen ing model designed by the Environmental Fate and 

### Effects Division (EFED, 2001a) of the Office of Pesticide Programs to estimate the concentrations found in drinking water from surface water sources for use in human health risk assessment. As such, it prov ides upper bound values on the concentrations that might be found in drinking water due to the use of a pesticide. FIRST is a single event model (one runoff event), but can account for spray drift from multiple applications. Spray drift (resulting in dir ect deposition of the pesticide into the reservoir) is assumed to be 16% of the applied active ingredient for aerial application, 6.3% for orchard air blast application, and 6.4% for other ground spray application. FIRST is hardwired to represent the Inde x Reservoir, a standard water bod y used b y the Office of Pesticide Programs to assess drinking water exposure (Office of Pesticide Programs, 2002). It is based on a real reservoir (albeit not currentl y in active use as a drinking water supply), Shipman Ci ty L ake in I llinois, that is known to be vulnerable to pesticide contamination. The single runoff event moves a maximum of 8% of the applied pesticide into the reservoir. This amount can be reduced due to degradation on the field and the effects of bindin g to soil in the field. FIRST also uses a Percent Cropped Area (PCA) factor to adjust for the area within the watershed that is planted to the modeled crop. The default agricultural PCA is 0.87. ( **Ref. 3 and 4** ) For volatile and semi

- volatile compounds, Tier I modeling will tend to over

- estimate EDWCs because there are no parameters in SCI

- GROW and FIRST that explicitly take into account volatility

(ie., no vapor pressure input). Therefore, in reality , more of the compound will be volatilizing than Tier I can account for. If drinking water levels of concern are exceeded for over

- estimated Tier I EDWCs, Tier II modeling will be able to refine these EDWCs by

including volatility

considerations. Modeling Approach and Input Parameters Table 5 provides the i nput parameter values used for modeling of bifenthrin using SCI

- GROW. Table 6 provides the input parameter values used for modeling of bifenthrin using FIRST. As indicated earlier, no degradates were included in the modeling because none exceded 10% of the applied in the laboratory

studies.18



### Table 5. SCI **- GROW (v2.3) input parameter values for**  **bifenthrin use on**  **lettuce 1** 


### .

**PARAMETER (units) VALUE(S)**  **SOURCE COMMENT**  Maximum Application Rate (lb a.i./A) 0. 1 L abel.

– Number of Applications per Year 5 L abel. R epresents most - conservative scenario in which the total maximum rate per year is applied in one

application. Organic Carbon Partition Coefficient (Koc ; mL /g) 257,000 MRID: 254401
. Represents the median value of four values ranging from 131,000 to 302,000 mL/g for the parent

compound. Aerobic Soil Metabolism Half

- life (days) 130.5 MRID : 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278
. Represents the median half

- life of six values available (132, 250, 129, 115, 156, 96.8 days)

.

**1** Parameters are selected as per Guidance for Selecting Input Param eters in Modeling the Environmental Fate and Transport of Pesticides; Version I, February 28, 2002. 

### Table 6. FIRST (v1.0) input parameter values for **bifenthrin use on**  **lettuce 1** 


### .

**P ARAMETER (units)**  **VALUE(S) SOURCE**  **COMMENT** Application Rate (lb a.i./A) 0.1 ` L abel.

– Number of Applications 5 Label

. - - Interval between Applications (days) 3 Label

. - - Percent Cropped Area (decimal) 0.87
- - National default. Soil Partition Coeffici ent (K d ; (mL/g) or K OC (mL /g OC )) 275,000 MRID: 254401
. Represents the lowest non

- sand K OC value among four values ranging from 131,000 to 302,000 mL/g ; the K OC model was utilized as per recommendation of the SAP.

. Aerobic Soil Metabolism Half

- life (days) 176.4 MRID : 141202, 254411, 532540, 251728, 254401, 073225, 073174, 251278
. Represents the 90 th percentile of the upper confidence

bound on the mean o f six half

- life values: 132, 250, 129, 115, 156, 96.8 days; mean = 146.5 days; std. dev.=

49.6 days
Wett ed in? No L abel. – Depth of I

ncorporation (inches) 0 L abel. – Method of Application Aerial spray L abel. – Solubility in Water @ 2 2 O C, unbuffered (mg/L or ppm) 0.000014 La skowski 2002 – Aerobic Aquatic Metabolism Half

- life (days) 352.8 MRID : 141202, 25 4411, 532540, 251728, 254401, 073225, 073174, 251278
. No aerobic aquatic metabolism data are available and

the pesticide is hydrolytically stable, 2X the aerobic soil metabolism half

- life input value is used.
Hydrolysis Half

- life @ pH 7 (days) 0 ACC: 251 728, MRID: 132539 Stable. Aquatic Photolysis Half

- life @ pH 7 (days) 0 ACC: 264642

– **1** Parameters are selected as per Guidance for Selecting Input Param eters in Modeling the Environmental Fate and Transport of Pesticides; Version I, February 28, 200219



### Modeling Results **Table 7. Maximum Tier I Estimated Drinking Water Concentrations (EDWCs) for drinking water risk assessment based on aerial application of**  **bifenthrin .**  **DRINKING WATER SOURCE (MODEL USED)**  **USE (rate modeled) MAXIMUM ESTIMATED DRINKING WATE**  **R CONCENTRATION (EDWC) ( ppb)**  Groundwater ( SCI
- GROW ) Lettuce (0. 5 lb a.i./A/season ) Ac ute and Chronic 0.0140 Surface water (FIRST) Lettuce (0. 5 lb a.i./A/season ) Ac ute 0.0140 Lettuce (0. 5 lb a.i./A/season ) Chronic 0.00300 

### SCI

- GROW conce ntration (ppb) represents the groundwater concentration that might be expected in shallow unconfined aquifers under sandy soils. Output is used for both acute and chronic endpoints. FIRST concentrations (ppb) represent untreated surface water concentratio ns. The peak day concentration (over 30 years) is used for acute endpoints and the annual average concentration (over 30 years) is used for chronic endpoints. The estimated concentrations provided in this assessment are conservative estimates of concentrations in drinking water. If dietary risks require refinement, higher tiered crop

specific and location

- specific models and modeling scenarios can be utilized. **Monitoring Data** Monitoring data usually provide different kinds of information than modeling (e.g., monitoring reflects current use pattern, underestimates frequency of occurrence, often misses peaks, inputs cannot be adjusted as modeled ones can, usually done for purposes other than characterizing exposure from a particular pesticide), and, conse quently, tend to complement the modeling rather than refine it. In general, a useful interpretation of monitoring values requires in

- depth assessment of the data, which is beyond the scope of a Tier I assessment. **Drinking Water Treatment** It is likel y that primary

treatment may

reduce the levels of cy

permethrin due to its tendency to bind. However, there is no information available at this time to determine the levels of reduction ( **Ref. 7**  )

. **CONCLUSIONS** The following can be concluded about bifenthrin:  This is a Tier I level analy sis, refinements may be available should they

be needed. The acute levels of surface drinking waters was 0.0140 ppb, the chronic level of drinking waters was 0.0140 ppb of bifenthrin. The groundwater concentration of cypermethrin, suitable for acute and chronic is 0.000300 ppb. All the concentrations were limited by the solubility

limit of bifenthrin. It was assumed that the maximum application rate was20



### used on lettuce, with the minimum interval between applications. The ma jor uncertainty is presence of acetonitrile in several of the laboratory experiments. Furthermore, the batch equilibrium constants were obtained at only one concentration (no Freundlich isotherms).  Despite the weaknesses of the data, this is considered a conservative (screening level) anal ys is.21



## APPENDIX SCI
- GROW and FIRST model output files.
RUN No. 1 FOR Bifenthrin ON Lettuce * INPUT VALUES *

-------------------------------------------------------------------- RATE (#/AC) No.APPS & SOIL SOLUBIL APPL TYPE %CROPPED INCORP ONE(MULT) INTERVAL Koc (PPTr) (%DRIFT) AREA (IN)

-------------------------------------------------------------------- .100( .474) 5 7 275000.0 14.0 AERIAL(16.0) 87.0 .0
FIELD AND RESERVOIR HALFLIFE VALUES (DAYS)

-------------------------------------------------------------------- METABOLIC DAYS UNTIL HYDROLYSIS PHOTOLYSIS METABOLIC COMBINED (FIELD) RAIN/RUNOFF (RESERVOIR) (RES.

- EFF) (RESER.) (RESER.)

-------------------------------------------------------------------- 176.40 2 N/A .00

- .00 352.80 352.80 UNTREATED WATER CONC (NANOGRAMS/LITER (PPTr)) Ver 1.0 AUG 1, 2001

--------------- ----------------------------------------------------- PEAK DAY (ACUTE) ANNUAL AVERAGE (CHRONIC) CONCENTRATION CONCENTRATION

--------------------------------------------------------------------

14.000 14.000

SCIGROW VERSION 2.3 ENVIRONMENTAL FATE AND EFFECTS DIVISION OFFICE OF PESTICIDE PROGRAMS U.S. ENVIRONMENTAL PROTECTIO N AGENCY

SCREENING MODEL FOR AQUATIC PESTICIDE EXPOSURE SciGrow version 2.3 chemical:Bifenthrin time is 1/18/2006 10:23:25

------------------------------------------------------------------------ Applicatio n Number of Total Use Koc Soil Aerobic rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

------------------------------------------------------------------------ 0.100 5.0 0.500 2.5 7E+05 130.5

------------------------------------------------------------------------ groundwater screening cond (ppb) = 3.00E
- 03* *Estimated concentrations of chemicals with Koc values greater than 9995 ml/g are beyond the scope of the regressio n data used in SCI
- GROW development. If there are concerns for such chemicals, a higher tier groundwater exposure assessment should be considered, regardless of the concentration returned by SCI
- GROW. *************************************************** *********************22



### M olecular structure of BIFENTHRIN
.

************************************************************************ **References:** 1. Policy Establishing Current Versions of Exposure Models and Responsibility for Model Maintenance (11/06/2002) 2. SCI GROW: Users Manual (11/01/2001, revised 08/23/2002) 3. FIRST Users Manual (08/01/2001) 4. FIRST: A Screening Model to Estimate Pesticide Concentrations in Drinking Water (05/01/2001) 5. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of Pesticides, Version II (02/28/2002) 6. Use of the Index Reservoir and Percent Crop Area in EFED Drinking Water Assessments (12/01/1999) 7. The Incorporation of Water Treatment Effects on Pesticide Removal and Transfo rmations in Food Quality

Protection Act (FQPA) Drinking Water Assessments (10/25/2001) 8. Laskowski, D.A. 2002. Rev. Environ. Contam. Toxicol. 174:49

- 170 9. Tomlin, C. editor. 1994. The Pesticide Manual 10 th 

### Edition. British Crop Protection Council and Roy al Society of Chemistry , UK.