OFFICE OF CHEMICAL SAFETY

AND POLLUTION PREVENTION

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON, 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 Barcode 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 Branch 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 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, respectively, 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 waters assessment results do not change from the previous ones. For 

electronic copy of the last assessment see Attachment 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 in 
2

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 highest 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 of 

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 WATER 

CONCENTRATION (EDWC) ( ppt)

Groundwater (SCI-GROW) Lettuce (0.5 lb. a.i./A/season) Acute and Chronic 3.00

Surface water (FIRST) Lettuce (0.5 lb. a.i./A/season) Acute 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 labels for Brigade 2EC Insecticide/ 

Miticide and Brigade WSB Insecticide/ Miticide.

Table 2. Summary of new uses for bifenthrin, based on the proposed supplemental labels for Brigade 2EC 

Insceticide/ 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

INCORPORATION 

DEPTH 

(inches) PHI

Grass Forage, Fodder, and Hay 

Group and Grass Grown for 

Seed, Pasture and Rangeland

(including bahiagrass, barnyardgrass, 

bentgrass, Bermudagrass, Kentucky 

bluegrass, big blueastem, smooth 

bromegrass, buffalograss, reed 

canarygrass, centipedegrass, crabgrass, 

cupgrass, dallisgrass, sand dropseed, 

Kentucky fescue, meadow foxtail, 

eastern gramagrass, side-oats grama, 

guinea grass, Indian grass, 

Johnsongrass, lovegrass, napiergrass, 

oatgrass, orchardgrass, pangolagrass, 

paspalum, redtop, Italian ryegrass, 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 hay
3

Attachment A: PREVIOUS DWA FOR BIFENTHRIN

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON 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, Soybean, Fruiting Vegetables (Subgroup 8), and 

Mayhaw

TO: Shaja Brothers, Risk Manager Reviewer

Daniel Rosenblatt, Chief

Barbara Madden, Chief

Minor Use Branch

Registration Division (7505P)

AND: PV Shaw, Chief

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

Environmental 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, respectively, 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 not 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 drinking 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 PCA). 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 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 WATER 

CONCENTRATION (EDWC) ( ppb)

Groundwater (SCI-GROW) Lettuce (0.5 lb. a.i./A/season) Acute and Chronic 0.00300

Surface water (FIRST) Lettuce (0.5 lb. a.i./A/season) Acute 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 labels

for Capture 2EC Insecticide/ Miticide, Brigade WSB Insecticide/ Miticide and Capture 1.15G 

Insecticide/ 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 Capture 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

INCORPORATION 

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/A
5

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 Capture 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

INCORPORATION 

DEPTH 

(inches)

PHI

Field corn (grain and 

silage), popcorn, 

field corn grown for 

seed-pre emergence

(PRE) or pre-plant 

incorporated (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 

specified

Ground or 

aerial

0 30

Sweet corn, sweet 

corn grown for seedat 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 

harvested

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 

harvested
6

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 Capture 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

INCORPORATION 

DEPTH 

(inches)

PHI

Dried shelled peas 

and beans: bean 

(Lupinus); bean

(Phaseoulus) field, 

kidney, lima, navy, 

pinto, tepary; bean

(Vigna) adzuki, 

blackeyed, catjang, 

cowpea, 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 broccoli, 

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, 

citron 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 7
7

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 Capture 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

INCORPORATION 

DEPTH 

(inches)

PHI

Caneberries

including 

blackberriesbingleber

rie dewberries 

lowberries marionberries olallie-berries 

young-berries 

loganberrie 

raspberries

0.1 2 0.2 One prebloom and 

one postbloom

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 

applications

0.5 

including 

soil 

applications

21 for 

foliar 

applications

In furrow, 

lay-by 

and foliar 

treatments

0 21
8

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 Capture 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

INCORPORATION 

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

Tree 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

Vegetables: 

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 STATES ENVIRONMENTAL PROTECTION AGENCY

WASHINGTON D.C., 20460

 OFFICE OF 

 PREVENTION, PESTICIDES AND

 TOXIC SUBSTANCES

COPY

PC Code 128825

DP Barcode D311012

MEMORANDUM

DATE: February 7, 2006

SUBJECT: Tier I Estimated Environmental Concentrations of Bifenthrin for the Use in the 

Human Health Risk Assessment.

TO: Shaja Brothers, Risk Manager Reviewer

Sidney Jackson, 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 Division (7509C)

FROM: José Luis Meléndez, Chemist

ERBV,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, respectively, for use in the human health risk assessment.

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 in 
10

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, 

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 EFED can perform a Tier II aquatic assessment, for 

surface waters.

EXECUTIVE SUMMARY 

Bifenthrin (chemical name 2-methylbiphenyl-3-ylmethyl (Z)-(1RS,3RS)-3-(2-chloro-3,3,3-

trifluoroprop-1-enyl)-2,2-dimethylcyclopropanecarboxylate, CAS# 82657-04-03, PC code 

128825) is a synthetic pyrethroid insecticide. Its structure has three rings, two phenyl rings 

attached to each other by a single bond, and a cyclopropyl ring. The chemistry of bifenthrin may

be dictated by its 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 pyrethroids 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 pyrethroids act 

as axonic poisons, affecting both the peripheral and central nervous systems, and share similar 

modes of action. Pyrethroids, including bifenthrin, stimulate repetitive action in the nervous 

system 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 paralysis of the insect.

This is a Tier I screening assessment using Tier 1 aquatic models SCI-GROW and FIRST, and 

maximum application rates for bifenthrin, with minimum application intervals. It was 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 bifenthrin; 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 hydrolysis, aqueous photolysis 

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, cilantro 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 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) Acute and Chronic 0.00300

Surface water (FIRST) Lettuce (0.5 lb. a.i./A/season) Acute 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 (pretreatment) 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 refined 

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 

corn

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 7
12

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 or 

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 prebloom and 

one postbloom

Ground or 

aerial

0 3

Artichoke 0.1 Not specified 15 Ground or 

aerial

0 5

Peppers 0.1 2 0.2 7 Ground 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

Tomatoes 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 14
13

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/Miticide 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, accordingly: 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 maximum 

application rate (maximum number of applications) with the maximum PCA.

Fate and Transport Characterization

Table 3 provides a summary of the major physical, 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)-

(1RS,3RS)-3-(2-chloro-3,3,3-

trifluoroprop-1-enyl)-2,2-

dimethylcyclopropanecarboxylate

– IUPAC name

 Molecular Weight 422.87 g/mol – –

 Solubility (22

oC) 1.4x10-5 mg/L Laskowski 2002 –

 Vapor Pressure (25

oC) 1.8 x 10-7 mmHg Tomlin, C. editor 1994. –

 Henry’s Law constant 7.2 x 10-3 Atm-m

3

/mol - -Estimated from vapor 

pressure and water solubility.

 pKa (20 oC) NA - - –

Octanol-Water Partition Coefficient 

(KOW)

3.00x106 Laskowski 2002 –
14

PARAMETER VALUE(S) (units) SOURCE COMMENT

 Hydrolysis Half-life 

 [pH 5, 7, 9; (25 oC)]

Stable ACC: 251728, MRID:

132539.

Stable at all pHs.

 Aqueous Photolysis Half-life Relatively stable ACC: 264642. Samples were not buffered 

and contained 30% 

acetonitrile as cosolvent. 

Natural sunlight was used.

 Soil Photolysis Half-life t1/2 = 147 days and 98.5 days for 

cyclopropyl and phenyl labels, 

respectively.

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 Cyclopropyl Phenyl 

SL 132 115

SiL 250 156

SiCL 129 96.8

MRID: 141202, 

254411, 532540, 

251728, 254401, 

073225, 073174, 

251278.

- - 

 Anaerobic Soil Metabolism Stable MRID: 264642 - -

 Anaerobic Aquatic Metabolism 

 Half-life

NA - - –

 Aerobic Aquatic Metabolism 

 Half-life

NA - - - -

 Organic Carbon Partition

 Coefficient (KOC)

131,000, 239,000, 302,000, 275,000

mL/gOC for the S, SL, SiL and SiCL,

respectively

MRID: 254401. –

 Soil Partition Coefficient (Kd)

992, 4192, 5430, 3690 mL/g

for the S, SL, SiL and SiCL, 

respectively

MRID: 254401. –

 Terrestrial Field Dissipation 

 Half-life

Site Half-lives

Champaign, 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 DT50 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, 40981808, 

40981812, 40981814, 

40981815, 40981816, 

40981817, 40981818, 

40981819.

- -

Bifenthrin is a synthetic pyrethroid. Its structure has three rings, two phenyl rings attached to 

each other by a single bond, and a cyclopropyl 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 indicate 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 hydrolysis at all pH’s. It is relatively stable to aqueous and soil photolysis 

and degrades slowly under both aerobic and anaerobic soil metabolism conditions (half-life 

range 97-250 days in 3 soils, and relatively stable, respectively). Bifenthrin is relatively

immobile in four soils tested (KOC range 131,000 to 275,000). Field studies show a pattern 

consistent with the laboratory studies, with relatively high persistence (half-lives ranging from 

78 to 345 days 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 suggests that bifenthrin will bioconcentrate in aquatic organisms. Bifenthrin 

was highly 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 partition to 

sediment in aquatic systems.

Bifenthrin has a vapor pressure of 1.8x10–7 mmHg, water solubility of 0.0140 ppb, and an 

estimated Henry’s law constant of 7.2x10-3atm-m

3

/mol. Based upon its Henry’s law constant 

and vapor pressure, bifenthrin is expected to have a moderate to low potential for volatilization 

from soil and water surfaces. Bifenthrin’s potential for volatilization is reduced significantly 

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 5.07x10-4μg/cm2

hr (average at 14 days), a relatively 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 several months. Due to 

its low solubility (0.014 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 employing 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, with no clear pattern of decline.

On the other hand, bifenthrin 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 pathways for bifenthrin, no transformation products were observed to 

be higher than 10% of the applied in any of the laboratory studies.

The major uncertainties with respect to the environmental fate studies on bifenthrin are related to 

the extremely low solubility of bifenthrin and the problems found when the registrant performed 

these studies. The hydrolysis, aqueous photolysis, and batch equilibrium studies were performed 

in unusually high concentrations of acetonitrile. 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 rely on a single point result.

Table 4 is a summary of degradate formation for bifenthrin. Note that, because bifenthrin is 

relatively stable or dissipates very slowly in all studies, no major transformation 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 ACC: 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 Metabolism . 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, 

40981812, 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 photolysis 

study, which was conducted in the presence of 30% acetonitrile. Even though no substantial 

photolysis 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 results of Prospective Ground Water studies against the Relative Index of 

Leaching Potential (RILP). The RILP is a function of aerobic soil metabolism and the soilwater 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 screening 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 provides 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 direct 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 Index 

Reservoir, a standard water body used by the Office of Pesticide Programs to assess drinking 

water exposure (Office of Pesticide Programs, 2002). It is based on a real reservoir (albeit 

not currently in active use as a drinking water supply), Shipman City Lake in Illinois, 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 binding 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 input 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 lettuce1.

PARAMETER (units) VALUE(S) SOURCE COMMENT

Maximum Application Rate (lb a.i./A) 0.1 Label. –

Number of Applications per Year 5 Label. Represents 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 Parameters 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 lettuce1.

PARAMETER (units) VALUE(S) SOURCE COMMENT

Application Rate (lb a.i./A) 0.1` Label. –

Number of Applications 5 Label. - -

Interval between Applications (days) 3 Label. - -

Percent Cropped Area (decimal) 0.87 - - National default.

Soil Partition Coefficient (Kd; (mL/g) or 

KOC (mL/gOC))

275,000 MRID: 254401. Represents the lowest non-sand KOC value among four

values ranging from 131,000 to 302,000 mL/g; the KOC

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 90th percentile of the upper confidence 

bound on the mean of six half-life values: 132, 250, 

129, 115, 156, 96.8 days; mean = 146.5 days; std. dev.= 

49.6 days

Wetted in? No Label.

–

Depth of Incorporation (inches) 0 Label.

–

Method of Application Aerial spray Label.

–

Solubility in Water @ 22

OC, unbuffered 

(mg/L or ppm)

0.000014 Laskowski 2002

–

Aerobic Aquatic Metabolism Half-life 

(days)

352.8 MRID: 141202, 

254411, 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: 251728, 

MRID: 132539

Stable. 

Aquatic Photolysis Half-life @ pH 7 (days) 0 ACC: 264642 –

1

Parameters are selected as per Guidance for Selecting Input Parameters in Modeling the Environmental Fate and 

Transport of Pesticides; Version I, February 28, 2002
19

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 WATER 

CONCENTRATION (EDWC) ( ppb)

Groundwater (SCI-GROW) Lettuce (0.5 lb a.i./A/season) Acute and Chronic 0.0140

Surface water (FIRST) Lettuce (0.5 lb a.i./A/season) Acute 0.0140

Lettuce (0.5 lb a.i./A/season) Chronic 0.00300

SCI-GROW concentration (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 concentrations. 

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 cropspecific 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, consequently, 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 likely that primary treatment may reduce the levels of cypermethrin 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 analysis, 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 was 
20

used on lettuce, with the minimum interval between applications. The major 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) 

analysis. 
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 PROTECTION AGENCY

 SCREENING MODEL

 FOR AQUATIC PESTICIDE EXPOSURE

SciGrow version 2.3

chemical:Bifenthrin

time is 1/18/2006 10:23:25

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

 Application Number of Total Use Koc Soil Aerobic

 rate (lb/acre) applications (lb/acre/yr) (ml/g) metabolism (days)

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

 0.100 5.0 0.500 2.57E+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 regression 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

Molecular structure of BIFENTHRIN.

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

References:

1. Policy Establishing Current Versions of Exposure Models and Responsibility for Model 

Maintenance (11/06/2002)

2. SCIGROW: 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 Transformations 

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 10th Edition. British Crop Protection 

Council and Royal Society of Chemistry, UK.