UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

PC Code: 000586 

DP Barcode: 402259 

November 12, 2012 

MEMORANDUM 

Subject: 

To: 

Through: 

From: 

Registration Review: Preliminary Problem Formulation for Bifenazate 

Garland Waleko, Chemical Review Manager 

Kevin Costello, Chief 

Risk Management and Implementation Branch II 

Pesticide Re-evaluation Division (7508P) 

Dana Spatz, Branch Chie~.oc:::::~~~ Rosanna Louie-Juzwiak, RAPL ~ ..,.__,.,.,_........_ 

Environmental Risk Branch III 

Environmental Fate and Effects Division (7507P) 

Katherine Stebbins, Biologis~o~~P ,-;... M I\ lt~\ 1~ James Hetrick, Ph.D., Senior cl'; ist~..-1-r.fn ,A:t_. 11 ( 11/1 Z.., 

Environmental Risk Branch III 

Environmental Fate and Effects Division (7507P) 

The Environmental Fate and Effects Division (EFED) has completed the problem formulation in 

support of the Registration Review of the insecticide, bifenazate (PC Code 000586) (attached). 

This document is intended to provide an overview of what is currently known regarding the 

environmental fate and ecological effects associated with bifenazate and its transformation 

products. Uncertainties regarding attributes of the parent compound and its transformation . 

products are also outlined. It describes the preliminary ecological risk hypothesis and the 

processes that will be used during the completion of ecological risk assessment in support of 

registration review. 

Page 1 of32 
Page 2 of 32 

1. Introduction

Bifenazate is a selective miticide/insecticide in the carbazate class, which controls the motile 

stage of mites either by direct contact or through contact with foliar residues. The mode of action 

of bifenazate is to block or close the GABA (gamma aminobutyric acid)-activated chloride 

channels of susceptible pests, resulting in over excitation of the peripheral nervous system. The 

structure of bifenazate can be found in Appendix E and the chemical names and other identifiers 

can be found in the chemical identity table (Table 3). Bifenazate is currently registered for use 

on a variety of agricultural and non-agricultural use sites. 

Agricultural Use Sites

Bifenazate may be applied to the following bearing or non-bearing crops: avocados, caneberries, 

cotton, cucurbits, dry beans (except soybean) subgroup, fruiting vegetables, small vine climbing 

subgroup (except kiwi), hops, legume vegetables (succulent- peas and beans including shelled 

soybean), mint, okra, pome fruits, tuberous and corm vegetables, low growing berries, stone 

fruit, tree nuts, and tropical fruit. Additionally, bifenazate may be applied to the following nonbearing crops (not to bear fruit within 1 year of application): berries (blueberry, highbush, 

elderberry, and huckleberry), citrus, currants, dates, figs, and persimmons. 

Non-Agricultural Use Sites

Bifenazate may be applied to ornamentals (including bedding plants, flowering plants, foliage 

plants, bulb crops, perennials, trees and shrubs) in greenhouses/shadehouses, nurseries, 

Christmas tree/conifer plantations, residential areas, as well as commercial/industrial/institutional 

areas including golf courses, parks, athletic fields, rights-of-way and other easements. 

Bifenazate is registered for 10 active Section 3 registrations, 6 SLN/Section 24c (ID, NV, OR, 

UT, WA, WY) and one section 18 for Nevada (timothy hay). Formulation types include wettable 

powder, soluble concentrate, flowable concentrate, and water dispersible granules. Applications 

may be made via aerial, ground (compressed air, hydraulic ground boom, air blast sprayers, and 

hand-held/hose end sprayers), and chemigation equipment. 

For agricultural crops, the maximum single application rates range from 0.38-0.75 pound of 

active ingredient per acre (lb a.i./A), with 1-2 applications allowed, depending on the crop. The 

highest annual rates are for legume vegetables (subgroup 6A and B), dried shelled beans (except 

soybeans), and root and tuber vegetables, for which applications of 0.75 lb a.i./A may be applied 

twice per crop cycle. The upcoming assessment will factor in the number of crop cycles per year 

for the individual crops. The use rates for non-agricultural applications to ornamentals range 

from one application at 0.38 applied twice per year to one application of 0.5 lb a.i./A per year. 

One label for home and garden uses (EPA Reg. No. 400-517), lists only the concentration of the 

spray (1⁄2 tsp of product per gallon) with directions to apply as a full coverage spray to the foliage 

and as often as every 30 days. Assuming a finishing spray volume of 400 gallons/A (which is 

what is recommended for use on ornamentals on the Floramite labels 400-508 and 400-509), the 

rate for the uses on 400-517 is anticipated to be equivalent to 0.5 lb a.i./A to be applied every 30 

days (6 lb a.i./A per year). The BEAD LUIS reports (U.S.EPA, 2012) list the use patterns and 

maximum use rates for the current uses of bifenazate. Usage Information (from BEAD 

Chemical Profile for Registration Review: Bifenazate, 2012) 
Page 3 of 32 

Agricultural Use

As reported in private market research surveys, overall bifenazate use in agriculture has steadily 

increased from 2002 to 2010. On average, approximately 110,000 pounds of bifenazate is 

applied annually to 230,000 acres at an average rate of 0.50 lbs a.i./acre. The crops with the 

highest use (in terms of total pounds a.i. applied) are strawberries, raisin grapes, almonds, 

potatoes, wine grapes, and table grapes.

Non-Agricultural Use

According to USDA NASS surveys of pesticide use in nursery and floriculture (2000, 2003, 

2006, and 2009), bifenazate usage averaged 3,450 pounds applied annually at an overall 

application rate of 0.151 lb a.i./acre. These estimates of usage do not include homeowner uses. 

2. Conclusions from Previous Risk Assessments

2.1. Ecological Risk Assessments

EPA has conducted multiple ecological risk assessments in recent years for bifenazate and the 

degradate D-1989 and these assessments will serve as a basis for this problem formulation 

document, as well as for the risk assessment to be conducted in registration review. In 2007 

(09/07), a new use assessment was conducted for use on tropical fruits, caneberries, and edible 

podded legume vegetables and succulent shelled soybeans. In 2009 (02/09), there were two 

assessments conducted. One assessment was to add new uses (grasses, dry beans, field and sweet 

corn) and also assess a rate increase for the edible podded legumes and succulent soybeans. The 

second 2009 (10/09) assessment was to assess increases in rate and the number of allowable 

annual applications. An assessment was conducted in 2010 (04/10) for uses on avocado, tropical 

fruit, low growing berries, and small tree climbing fruit. The latest assessment was completed in 

December 2011 for the proposed new uses on Herb 19A (except chive and chervil), fruiting 

vegetables (Group 8-10), pome fruit (Group 11-10), and Timothy Grass forage and hay. 

Based on the most recent assessments conducted in 2009 and 2010, there are risk 

concerns for birds (and as surrogate, terrestrial-phase amphibians and reptiles) on an 

acute and chronic exposure basis (acute RQ =0.48; chronic RQ = 16) and also for 

endangered estuarine/marine invertebrates on an acute exposure basis (acute RQ =0.16). 

Levels of concern were not exceeded for mammals (see note in section 4.2), fish, 

freshwater invertebrates, and terrestrial/aquatic plants. Table 1 provides a summary of 

the major ecological conclusions presented in the previous risk assessments. 

Table 1. Summary of Risk Concerns Identified for Bifenazate in Previous Assessments

Exposure 

Basis Birds Mammals

Terrestrial

Plants

Terrestrial

Inverts. 

(honey bee 

hazard)

Fish Aquatic 

Inverts

Aquatic 

Plants

Groundwater 

Contamination Persistence Degradates of Concern

Acute √ -- -- √ -- √ --

-- -- D-1989

Chronic √ -- -- -- * -- --

* Uncertain due to data gaps
Page 4 of 32 

2.2. Drinking Water Exposure Assessments

There have been numerous drinking water assessments to support bifenazate uses. Table 2

provides a summary of the surface water modeling for drinking water assessments for bifenazate. 

Because the Health Effects Division (HED) deemed the bifenazate degradation product 1,1'-

biphenyl, 4-methoxy (D1989) as a degradate of concern, it has been considered in the drinking 

water exposure modeling using a total toxic residue approach (D276801, T. Bloem, 16-Aug2001). Based on the use for succulent peas and beans, the highest EDWC for bifenazate and its 

degradation product D1989 is not expected to exceed 37.3 μg/L for the daily peak concentration 

and 11.2 μg/L for the annual average concentration. A new drinking water assessment may be 

required if a new dietary analysis is necessary after review of additional toxicity data. In order to 

refine the drinking water assessment for bifenazate, additional data on aerobic soil metabolism 

and aerobic aquatic metabolism would be expected to address uncertainties in the exposure 

assessment.

Table 2: Summary of Previous Drinking Water Assessments for Bifenazate and Degradation Product 

D1989. 

Crop Residues Model

Application 

Rate Peak Annual 

Average Date Comment

(lb 

a.i./A/year) μg/L

Cotton Parent FIRST

0.75

3.69 0.025 9/17/01 PCA=0.20

Hops 16.40 0.114 PCA=0.86

Hops D1989 FIRST 17.8 4.96 11/23/01

Cotton 4.08 1.14 PCA=0.87

Potatoes Parent 

+D1989 FIRST

19.1 5.71 10/9/03

PCA=0.86

Strawberries 1.0 22.8 6.38

Hops 0.75 17.8 4.96

Pea, Tuberous, 

Corm Vegetables Referred to previous assessment on 10/9/03

Grasses, Dry 

Parent 

+D1989

FIRST 0.75 19.1 5.7 9/30/08 PCA=.87

Beans, Edible 

podded legumes, 

succulent-shelled 

peas, beans, 

soybeans,

FIRST

1.50 37.3 11.2 PCA=.87

Field/sweet corn FIRST 0.75 10.1 3.0 PCA=.87

Cane berries

Parent 

+D1989

PRZM/EXAMS

1.50

8.1 1.8 8/3/09

PCA=.87

Tropical Fruit 16.7 2.0

Potatoes 10.9 2.5

Tree Fruit 8.4 0.8

Avocado

Parent 

+D1989 0.90

8.6 2.7 1/28/10

Tropical Fruit 16.7 2.0

Low Growing 

Berry 21.3 4.1

Small vine 

climbing fruit 0.45 10.3 3.0

Herb Subgroup 

19A

Fruiting 

Vegetable Group 

8-10

Parent 

+D1989 PRZM/EXAMS

0.5 9.9 1.8

10/17/11 PCA=.87
Page 5 of 32 

Crop Residues Model

Application 

Rate Peak Annual 

Average Date Comment

Pome Fruit 

Group 10-11 9.3 2.4

Timothy Grass 0.747 9.9 1. 8

2.3. Clean Water Act Programs

Bifenazate is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5. In addition, no Total Maximum Daily Loads (TMDL) have been developed for bifenazate

based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id

=885&p_pollutant_group_name=PESTICIDES. More information on impaired water bodies and 

TMDLs can be found at http://www.epa.gov/owow/tmdl/. 

The Agency invites submission of water quality data for this pesticide. To the extent possible, 

data should conform to the quality standards in Appendix A of the OPP Standard Operating 

Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s 

Registration Review Risk Assessment and Management Process (see: 

http://www.epa.gov/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf), in order to ensure 

they can be used quantitatively or qualitatively in pesticide risk assessments. 

Surface Water

There are no water monitoring data for bifenazate or D1989 in the USGS National Water-Quality 

Assessment Program (NAWQA), USEPA/USGS Pilot Reservoir Monitoring Program, USDA 

Pesticide Data Program (PDP), and California Department of Pesticide Regulation (CDPR). 

3. Environmental Fate and Transport

Chemical identification and physical chemical properties of (2-(4-methoxy-[1,1’-biphenyl]-3-yl) 

- methylethyl ester (bifenazate) and its degradation product 1,1'-biphenyl, 4-methoxy (D1989) 

are provided in Table 3. 
Page 6 of 32 

Table 3. Chemical Identification Information for Bifenazate and Its Degradation Product D1989

Physical and Chemical Properties

Properties Bifenazate D1989

Chemical name (2-(4-methoxy-[1,1’-biphenyl]-

3-yl)-methylethyl ester 1,1'-biphenyl, 4-methoxy

Chemical Abstract Service number 149877-41-8 613-37-61

Empirical Formula C17H20N203 C13H120

Molecular weight 300.36 184

Aqueous Solubility 3.76 mg/L (20oC) 27.7mg/L 2 (25oC)

pKa 12.94 data not available

Vapor Pressure (25°C) <1 x 10-7 mmHg 3.76 x 10-4 mmHg 3 (25oC)

Octanol-water partition coefficient (log Kow) 3.4 3.8

Based on available environmental fate data, the parent compound, bifenazate is expected to be 

slightly mobile, but not persistent in the environment (Table 4). It is expected to rapidly 

dissipate in aquatic environments as the result of both hydrolysis (t1/2 = 7.7 hours at pH 7) and 

direct aqueous photolysis (t1/2 = 16 hours). Photodegradation of bifenazate in soil is not 

expected because there was rapid degradation of bifenazate in the dark control of 

photodegradation in soil study. Major hydrolysis degradation products (>10% of applied 

radioactivity) of bifenazate include diazenecarboxylic acid, 2-[4-methoxy(1,1’-biphenyl)-3-yl], 

1-methylethyl ester (D3598), [1,1’-Biphenyl]-3,4-diol (D9472), and 4-methoxybiphenyl 

(D1989). A major photodegradation product in water is 4-Methoxy-[1,1’-biphenyl]-3-ol 

(D9963). 

Table 4. Select Physical, Chemical and Environmental Properties of Bifenazate and the Major

Degradate of Exposure Concern, D1989.

Environmental Fate Properties

 Environmental Fate Properties Bifenazate D1989

Hydrolysis half-lives (pH 5, pH 7, pH 9) t 1⁄2 = 2.68 days, 7.7 hours, 0.45 

hours data not available

Aqueous Photolysis half- life t 1⁄2 = 16.2 hours data not available

Soil Photolysis half- life Stable1 data not available

Aerobic Soil Metabolism half-life t 1⁄2 = 7.3 hours t 1⁄2 = 24.4 days3

Anaerobic Aquatic Metabolism half-life t 1⁄2 = 78 days data not available

Mobility Immobile2 Koc = 3011–61894

Terrestrial Field Dissipation half-life t 1⁄2 = 5 days

No residues detected after 60 

days, or below 30 cm soil depth, 

under field conditions4

1- Rapid degradation of bifenazate was observed in the dark control, which indicates photodegradation on soil is not a probable route of 

dissipation. 

2- Immobile mobility classification based on soil column leaching study (MRID 44464955).

3- Aerobic soil metabolism degradation half-life for D1989 (MRID 45144002)

4- Batch equilibrium coefficients for D1989 (MRID 44464956)

 

1 PMRA Regulatory Note REG 2006-01 http://www.pmra-arla.gc.ca/english/pdf/reg/reg2006-01-e.pdf

2 EPI Suite 2000 (v3.12) WSKOW v.141

3 EPI Suite 2000 (v3.12) MPBPWIN v1.41 (modified grain method)

4 PMRA Regulatory Note REG 2006-01 http://www.pmra-arla.gc.ca/english/pdf/reg/reg2006-01-e.pdf
Page 7 of 32 

Bifenazate is rapidly degraded in aerobic soil (t1/2 = 7.2 hours) into the major degradate 4-

methoxybiphenyl (D1989). The other major degradation product in aerobic soil is D3595. In 

anaerobic environments, bifenazate is degraded with a half-life of 77.9 days. Major degradation 

products in anaerobic environments include (1,1’-Biphenyl)-4-ol (A1530) and desmethyl D3598. 

Structures of degradation products are shown in Appendix E. 

Based on soil column leaching data and HPLC soil column Koc estimation, bifenazate is slightly 

mobile in most soils, as is the major degradate D1989 (Koc=3011-6189). The low vapor pressure 

and Henry’s Law constant limits the potential of bifenazate to volatilize from soil and water. 

Given that bifenazate is rapidly hydrolyzed, photodegraded, and microbially-degraded, it has low 

potential for bioaccumulation. 

Terrestrial field dissipation studies in Washington and North Carolina confirm laboratory study 

results that bifenazate degrades rapidly (t1/2=5 days) and is immobile in bare-ground soil. Major 

degradation products, D1989 or D3598, were detected at a maximum concentration of 0.03 

mg/kg. No bifenazate residue detections were found in soil depths > 6 inches. 

3.1. Transformation Products

An analysis of the degradation product profiles among laboratory studies indicates a common 

degradation profile for bifenazate; it degrades to form D3598, which is a precursor to D1989, 

D9472, D9963, and A1530 (Table 5). Additionally, a large fraction of 14C residue was detected 

(51.5-73.8%) in bound soil/sediment fractions. Data indicate that the biphenyl moiety of 

bifenazate is prone to incorporation into soil/sediment organic matter. 

Table 5: Maximum Concentration of Bifenazate Degradation Products in Environmental 

Fate Studies

Environmental Fate 

Study MRID Study Conditions

Degradation 

Product

Maximum 

Percentage 

Formed (%)

Hydrolysis 44464952 pH=4 D3598 22@14 days

D1989 9.7@14 days

D9472 83.6@ 30 days

pH=7 D3598 63@ 1 day

D1989 7.2@339 hours

D9472 43.4@2 days

D9963 5.2@768 hours

pH=9 D3598 23.5@1.8 hour

D1989 9.9@20.6 hours

D9472 64.1@2.8 hours

D9963 6.6@18.6 hours

Photolysis in Water 44464953 Dark Control; pH=5 D3598 55.9@78 hours

D9472 45.5@150 hours

D1989 11.6@150 hours

Irradiated; pH=5 D3598 74.4@27.9 hours

D9472 15.9@149.8 hours

D1989 13.8@53.8 hours

D9963 31.7@150.5 hours

Photolysis on Soil 44522601 Dark Control;SL;pH-6.7 D3598 77.5@2 hours
Page 8 of 32 

D1989 22.1@3 days

Irradiated; SL;pH-6.7 D3598 84.3@2 hours

D1989 11.2@3 days

Aerobic Soil 

Metabolism

44464954 SL; pH=6.9;1.9%OM D3598 92@0.5 hours

D1989 26.8@3days

Anaerobic Aquatic 

Metabolism

44522602 Loam sediment (pH=6.6;

6.9% OM) with natural 

water (pH=7)

A1530 24.@294 days

Desmethyl 3598 14.7@231 days

D3598 3.7@ 0 days

Terrestrial Field 

Dissipation

44464958 Washington State; Sand 

soil; bareground; 

application rate (0.6 lb 

a.i./A)

D1989 or D35981 0.02 mg/kg @ 4 

days posttreatment 

in 0-6 inch soil

44464957 North Dakota; SL soil; 

bareground; application 

rate (0.61 lb a.i./A)

D1989 or D35981 0.03 mg/kg (10% 

of applied) @ 7 

days posttreatment 

in 0-6 inch soil

1 Common moiety extraction for D3598 and D1989.

Experimental environmental fate data have been submitted for D1989. D1989 degraded in 

loamy sandy soil with a half-life of 24.4 days (MRID 45144002). It is slightly mobile 

(Koc=3011-6189) in mineral soils (MRID 44464956). However, D1989 may exhibit sufficient 

persistence and hydrophobicity (log Kow=3.8) to allow bioaccumulation. Although the vapor 

pressure and Henry’s Constant of D1989 indicate volatilization as a potential route of 

dissipation, volatilization of D1989 was not observed in laboratory studies. 

Environmental fate properties for other degradation products were predicted using EPISuite 

(Table 6). This model simulation indicates that degradation products are not expected to be 

readily biodegradable. However, D3598 degraded with a single first order half-life of 9.242 

hours in aerobic soil (MRID 44464954). The mobility of the degradation products ranges from 

moderately mobile to slightly mobile. Additionally, the degradation products except D9472 have 

Kow values exceeding the OPP/EFED trigger for potential bioaccumulation. 

Table 6: Environmental Fate Properties of Bifenazate Degradation Products as Determined by 

EPIsuite 

Property

Degradation Product

D3598 D1989 D9963 D9472 A1530

Molecular Weight (g/mol) 298.34 184.24 200.24 186.21 170.21

Vapor Pressure (mm Hg) 6.08E-7 3.76E-4 7.35E-6 7.89E-7 1.73E-5

Henry’s Constant (atm-m3/mol)1 6.001E-8 3.29E-6 1.977E-8 2.422E-10 8.977E-9

Solubility (mg/L) 3.977 27.7 94.94 798.2 431.6

Log Kow 4.10 3.84 3.10 2.80 3.20

Koc (L/kg) 7485 1274 728.7 642 727.7

Ready Biodegradation No No No No No

1-Henry Constant- Calculated using vapor pressure/water solubility

4. Receptors

Tables 7 and 8 provide a summary of the aquatic and terrestrial taxonomic groups, respectively, 

and the most sensitive surrogate species tested to characterize the potential acute and chronic 
Page 9 of 32 

ecological effects of bifenazate. In addition, the tables provide a preliminary overview of the 

potential acute toxicity of bifenazate by providing the acute toxicity classifications. Toxicity 

data for degradates have recently been submitted but have not been fully reviewed. A 

preliminary summary of the degradate data is provided in Appendix F. 

4.1. Effects to Aquatic Organisms

Based on the available data, bifenazate is classified as “highly toxic” to freshwater and 

estuarine/marine fish and invertebrates on an acute exposure basis. Despite the high toxicity, the 

exposure was low enough in previous assessments that there were no LOC exceedances for fish 

or freshwater invertebrates on an acute exposure basis. For estuarine/marine invertebrates, there 

were LOC exceedances on an acute exposure basis (acute RQs range from 0.01-to 0.16). Data 

are not available to assess the risk from chronic exposure to freshwater fish and also to 

estuarine/marine fish and invertebrates. 

For vascular aquatic plants, there were no effects reported at any of the test concentrations in the 

duckweed (Lemna gibba) study (EC50 = >3.82 mg/L) and for non-vascular plants, an EC50 = 

0.89 mg/L (NOAEC = 0.252 mg/L) was reported for green algae (Selenastrum capricornutum)

based on a reduction in cell density. 

Table 7. Summary of the Most Sensitive Endpoints from Aquatic Toxicity Studies for Bifenazate 

Taxonomic 

Group

Study 

Type

Surrogate 

Species

Toxicity Values 

(all units in terms 

of measured a.i.)

MRID and 

Classification

Acute 

Toxicity 

Classification

Freshwater 

fish 

Acute

Bluegill sunfish LC50 = 0.58 mg/L 44464931

(Acceptable) Highly toxic (Lepomis

macrochirus)

NOAEC = 0.30 mg/L 

Endpoint: survival 

and sublethal effects

Chronic No Data

Freshwater 

Invertebrates

Acute

Water flea EC50 = 0.50 mg/L

44464933

Highly toxic

(Daphnia magna)

NOAEC = ND 

Endpoint: 

Immobilization

(Acceptable)

Chronic

Water flea

NOAEC = 0.15 mg/L

45052216

(Daphnia magna)

LOAEC = 0.27 mg/L 

Endpoint: 

reproductive and 

growth effects

(Supplemental1)

Estuarine/ 

Marine Fish Acute

Sheepshead 

minnow

LC50 = 0.416 mg/L

45052214

Highly toxic (Cyprinodon

variegatus)

NOAEC = 0.136 

mg/L 

Endpoint: Survival

(Acceptable)
Page 10 of 32 

Chronic No data

Estuarine/ 

Marine 

Invertebrates 

Acute

Saltwater mysid

LC50 = 0.058 mg/L

45052213 Very highly 

(Americamysis toxic

bahia)

NOAEC = 0.04 mg/L 

Endpoint: Survival

(Supplemental2)

Chronic No data

Aquatic 

Plants

Nonvascular

Green algae EC50 = 0.89 mg/L

45052219

(Selenastrum 

capricornutum)

NOAEC = 0.252 

mg/L Endpoint: 

Reduction in cell 

density

(Acceptable)

Vascular

Duckweed EC50 = >3.82 mg/L

45052218

(Lemna gibba)

NOAEC = 3.82 mg/L 

No effect on frond 

number 

(Acceptable)

1 Classified as “Supplemental” because the water samples were not centrifuged or filtered prior to analysis even though a 

precipitate was observed in the mixing chamber of the highest concentration.

2 Classified as “Supplemental” because the water samples were not centrifuged or filtered prior to analysis even though a 

precipitate was observed in the mixing chambers and the mean measured concentrations at test termination were not maintained 

at >70% of the nominal concentrations.

4.2. Effects to Terrestrial Organisms

Parent bifenazate is classified as “practically non-toxic” to mammals and “slightly toxic” to birds 

on an acute exposure basis. On a subacute basis, bifenazate was classified as “moderately toxic” 

to the mallard with a LC50 of 656 mg/kg-diet. For chronic exposure to mammals, there was a 

reduction in body weight and cumulative weight gain for the males and females in the F1 

generation in a two-generation reproductive study with the laboratory rat (NOAEC = 20 mg/kgdiet). It should be noted that this endpoint for mammals is different from what was used in 

previous assessments (>200 mg/kg-diet), because the >200 mg/kg-diet endpoint was based only 

on effects to reproduction and did not consider the reduction in body weight. Because body 

weight change is an apical endpoint considered by EFED, the NOAEC value of 20 mg a.i./kg-bw 

will be the value used in the upcoming risk assessment. For birds, chronic effects were reported 

based on a reduction of eggs laid and set (LOAEC = 65 mg/kg-diet/NOAEC =20 mg/kg-diet). In 

the previous assessments, there were LOC exceedances for birds on both an acute (RQs from 

<0.01- 0.48) and chronic (RQs from 0.6-16) exposure basis. For the upcoming assessment, it is 

anticipated that there will be also be LOC exceedances for mammals (based on the revised 

endpoint) on a chronic exposure basis. 

Acute contact honeybee studies indicate that bifenazate is moderately toxic to honey bees (LD50

7.8 μg/bee). For terrestrial insects, EFED currently uses the honeybee data as a surrogate For 

terrestrial plants, the available toxicity studies with monocots and dicots indicate that bifenazate 

had no adverse effects on seedling emergence and vegetative vigor at the highest test 

concentration (2 lb a.i./A). 
Page 11 of 32 

Table 8. Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for Bifenazate 

Taxonomic 

Group

Study 

Type

Surrogate 

Species

Toxicity Values (all 

units in terms of 

measured a.i.)

MRID and 

Classification

Acute 

Toxicity 

Classification

Mammals

Acute Oral Laboratory rat LD50 >5000 mg/kg-bw 44464934

(Acceptable) Practically nontoxic

Chronic Laboratory rat NOAEL 20 mg/kg-diet 45076503

 

LOAEL= 80 mg/kg-diet

Endpoint: Decreased body 

weight and cumulative 

body weight gains in 

males and females

(Acceptable)

 

Birds

Acute Oral Bobwhite quail LD50 = 1032 mg/kg bw 44464928

(Colinus 

virginianus)

NOAEL= Not determined 

Endpoint: Mortality and 

sublethal effects

(Acceptable)

Slightly toxic

Subacute 

Dietary

Mallard LC50 = 656 mg/kg-diet 44464929 

(Anas 

platyrhynchos) Endpoint: Survival

(Acceptable) Moderately 

toxic

Mallard NOAEC = 20 mg/kg-diet 44872901

 

Chronic (Anas 

platyrhynchos)

LOAEC = 65 mg/kg-diet 

Endpoint: Reduction in # 

eggs laid and set per 

female

(Acceptable)

Terrestrial 

Insects

Acute 

Contact

Honey Bee LD50 = 7.8 μg/bee 

NOAEC = 2.7 μg/bee 

Endpoint: Survival 

44462315 

(Apis mellifera) (Acceptable) Moderately 

toxic

Terrestrial 

Plants

Seedling 

Emergence

Monocot -corn EC25 = >2.0 lb a.i./A 45052217 

NOAEC = 2.0 lb a.i./A (Acceptable)

Seedling 

Emergence

Dicot - soybean EC25 = >2.0 lb a.i./A 45052217 

NOAEC = 2.0 lb a.i./A (Acceptable)

Vegetative 

Vigor

Monocot - wheat EC25 = >2.0 lb a.i./A 45076502

 

NOAEC = 2.0 lb a.i./A (Acceptable)

 

Vegetative 

Vigor

Dicot - cabbage EC25 = >2.0 lb a.i./A 45076502

NOAEC = 2.0 lb a.i./A (Acceptable) 

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles.
Page 12 of 32 

4.3. Ecological Incidents

As of July 18, 2012, the Ecological Incident Information System (EIIS, version 2.1), which is 

maintained by the Agency’s Office of Pesticide Programs, returned one terrestrial plant incident 

in California attributed to bifenazate use with “possible” certainty (Table 9). Incident # I016036-

006 occurred in 2004 when a registered agricultural use product containing bifenazate was 

applied to almonds. Fifty-four acres of basil were reported to be damaged from possible spray 

drift from the airblast treatment to almonds. 

Table 9. Ecological Incidents Associated with Bifenazate 

Incident 

Number

Taxa 

Involved Magnitude Year Location Use

Legality 

of Use

Certainty 

Category Residues

Other 

Chemicals 

Involved

I016036-006

Terrestrial 

Plant

54 Acres 

(Basil) 2004 CA Almonds

Registered 

Use Possible

None 

reported

None 

reported

No ecological incidents were reported in the Avian Monitoring Information System (AIMS) 

database, which is maintained by the American Bird Conservancy, or in the IDS Aggregate 

Incident Reports’ database maintained by EPA. 

5. Conceptual Model

The environmental fate data for bifenazate show rapid degradation in terrestrial and aquatic 

environments. This rapid degradation results in formation of toxic degradation products with the 

potential for environmental exposure. Degradation products of bifenazate are D-1989, D-3598, 

D-9963, D-9472 and A-1530. Previous risk assessments have focused on bifenazate and the 

degradation product D-1989; however, additional information from the registrant indicates that

D-3598 has similar toxicity to bifenazate. Additionally, several ecotoxicology studies have been 

submitted for degradates D-1989, D-3598, and D-9472. Based on a preliminary review of the 

studies, the data tentatively suggest (until a full review of the studies has been completed) that D1989, D-3598, and D-9472 are generally similar in toxicity to bifenazate. Data are not available 

for degradate A-1530, however, since this degradation product is only formed in anaerobic 

aquatic environments it will not be included as a stressor of concern. While data are also not 

available for D-9963, given the similarities in structure of D-1989, D- 9963, D-9472, in the 

absence of data, it is assumed that D-9963 will also exhibit similar toxicity. Based on the 

environmental fate data and use information, potential routes of exposure for bifenazate and its 

degradation products are as follows: 

• Off-site movement of bifenazate is expected to be predominately by spray drift;

• Rapid degradation of bifenazate is expected to limit runoff and leaching potential;

• Degradation products of bifenazate are expected to be more persistent than bifenazate; 

• Off-site movement of bifenazate degradation products may be by runoff or erosion; 

• Bifenazate residues in soil are incorporated into soil organic matter;

• QSAR analysis indicates all degradation products except D9472 have Kow values 

exceeding the bioaccumulation (log Kow=3) trigger; and

• Volatilization may be a route of dissipation for D1989. 
Page 13 of 32 

 

6. Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment will 

be estimated. The use, environmental fate and ecological effects of bifenazate and its degradation 

products (D-3589, D-1989, D-9963, and D-9472) will be characterized and integrated to assess 

the overall risks. A total toxic residue approach will be used to assess the exposure to bifenazate 

(FIFRA SAP, 2008). This assessment process will assume that ecotoxicity of the degradation 

products - D-3589, D-1989, D-9963, and D-9472 is equivalent to bifenazate. 

Risk quotients (RQ) will be derived for total toxic residues (bifenazate, D-3589, D-1989, D9963, and D-9472) by dividing estimated environmental concentrations (EEC) by the most 

sensitive endpoint from the relevant, available toxicity data for bifenazate

6.1. Stressors of Concern

The residues of concern in this assessment will include bifenazate and its degradation products 

D-3589, D1989, D-9963, and D-9472. HED has identified the bifenazate degradation product 

D-1989 as a residue of concern and the registrant Chemtura has indicated that the degradation 

product D-3589 has insecticidal activity. Additionally, several aquatic ecotoxicology studies are 

now available for degradates D-1989, D-3598, and D-9472. Based on a preliminary screen of 

the submitted studies, the data suggests that the degradates are generally similar in toxicity to 

bifenazate for aquatic plants and animals. While for fish and aquatic invertebrates, the EC/LC50

values for D-3598 were generally an order of magnitude lower (i.e. more toxic) than the 

respective values for bifenazate this is within the normal range of variability that may occur for 

the same guideline test (especially when different species were used - as is the case with the fish

data). In addition to the aquatic toxicity data, data for acute toxicity to the earthworm (Eisenia 

fetida) were submitted for Bifenazate, D-1989, and D-3598. Based on a preliminary review of 

the data, the degradates may be slightly more toxic to the earthworm than the parent, however, 

terrestrial invertebrates are not assessed quantitatively in EFED assessments. Degradate D-9963 

is included as a residues of concern because it is a major degradate and is similar in structure to 

D-1989 and D-9472 (see Appendix E for the chemical structures). Therefore, based on the 

information available at this time, the degradates D-1989, D-3598, D-9472, and D-9963 are 

assumed to be equally as toxic as bifenazate and a total toxic residue approach will be used to 

estimate the summed environmental concentration of bifenazate, D-1989, D-3589, D-9472, and 

D-9963 (FIFRA SAP, 2008). Appendix F provides a summary of the degradate toxicity data in 

comparison to bifenazate. 

6.2. Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms as described at http://www.epa.gov/pesticides/science/models_db.htm. 

The models used to generate aquatic estimated environmental concentrations (EEC) are the 

Pesticide Root Zone Model (PRZM) coupled with the EXposure Analysis Model System 

(EXAMS). Model input values will be consistent with the most recent version of the Input 
Page 14 of 32 

Parameter guidance (current version 2.1; USEPA 2009). The model used to produce terrestrial 

EECs on food items is T-REX. Using the TREX model, we will assume that the conservative 

half-life value of 35 days for foliar residue dissipation will capture the parent and degradates, 

unless data becomes available to suggest that the 35-day half-life is inadequate. The model used 

to derive EECs relevant to terrestrial and wetland plants is TerrPlant. The AgDRIFT spray drift 

model (v2.01; May 2001) is used to assess exposures of organisms to bifenazate deposited on 

terrestrial or aquatic habitats by spray drift. KABAM (KOW (based) Aquatic BioAccumulation 

Model) v.1.0 will be used to estimate potential bioaccumulation of hydrophobic organic 

pesticides such as D-1989 in freshwater aquatic food webs and subsequent risks to mammals and 

birds via consumption of contaminated aquatic prey. These models are parameterized using 

relevant reviewed registrant-submitted environmental fate data. Because bifenazate and its 

degradation products D-1989, D-3589, D-9472, and D-9963are assumed to have similar toxicity 

to terrestrial and aquatic organisms, a total toxic residues approach will be used in the exposure 

modeling (FIFRA SAP, 2008). The predicted estimated environmental concentrations of total 

toxic residues (bifenazate, D-1989, D-3589, D-9472, and D-9963will be used to calculate risk 

quotients. 

For problem formulation, screens were conducted for the potential exposure from drinking water 

and inhalation. For drinking water, the Screening Imbibition Program (SIP v. 1.0, Released June 

15, 2010) was used to calculate an upper bound estimate of exposure. Exposure from drinking 

water alone was not determined to be a potential pathway of concern for avian or mammalian 

species on an acute basis and on a chronic exposure basis drinking water alone was not a concern 

for mammals; however, it is a potential concern for birds (Appendix A). This modeling does not 

take into account that drinking water may contribute to a total exposure that has the potential for 

effects on non-target animals when aggregated with other exposure pathways (dietary food 

sources, dermal, inhalation). Because there is a high degree of conservatism in the SIP 1.0 

exposure estimate, there is limited expectation that use scenarios not triggering a SIP 1.0 concern 

would contribute significantly to aggregate risks from water plus diet when a refined water 

exposure model is incorporated in the actual quantitative risk assessment. Detailed information 

about SIP v. 1.0, as well as the tool, can be found on the EPA’s website at 

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial. 

The Screening Tool for Inhalation Risk (STIR v.1.0, November 19, 2010) was used to calculate 

an upper bound estimate of exposure from inhalation. Based on the results of the STIR model, 

inhalation exposure alone was not determined to be a potential pathway of concern for avian or 

mammalian species on an acute basis (Appendix B). Inhalation exposure via spray drift and/or 

the vapor-phase of the pesticide alone does not appear to be of concern. The analysis of the 

inhalation route in STIR does not consider that aggregation with other exposure pathways such 

as dietary, dermal, or drinking water may contribute to a total exposure that has a potential for 

effects to non-target animals. However, the Agency does consider the relative importance of 

other routes of exposure in situations where data indicate that pesticide exposures through other 

routes may be potentially significant contributors to wildlife risk (USEPA, 2004). The risk 

characterization section will discusses the impact of the consideration of other routes of exposure 

that have been identified as potentially important, and the degree of certainty associated with 

screening-level risk assessment conclusions. Detailed information about STIR v.1.0, as well as 

the tool, can be found on the EPA’s website at: 
Page 15 of 32 

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial. 

6.3. Measures of Effect 

Toxicity data presented in Section 4 of this problem formulation will be used to calculate risk 

quotients. Any additional information submitted by the registrant or found in the open literature 

prior to conduct of the risk assessment will also be considered. The open literature studies are

identified using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007c), which employs 

a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, 

and wildlife. 

6.4. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to federally listed threatened and/or endangered species (“listed 

species”) from registered uses of pesticides in registration review. These assessments will be 

conducted in accordance with standard EPA procedures and good scientific judgment. The 

process for evaluating potential risks to listed species is further described at 

http://www.epa.gov/oppfead1/endanger/litstatus/riskasses.htm. 

6.5. Endocrine Disruptor Screening Program

Bifenazate is not included in the first group of 67 chemicals issued an order to conduct Tier 1 

EDSP testing. For additional information on the EDSP program, visit 

http://www.epa.gov/endo/. 

7. Preliminary Identification of Data Gaps 

7.1. Environmental Fate

The environmental fate database for bifenazate is complete to provide an understanding of 

dominant environmental dissipation pathways and to allow quantification of estimated 

environmental concentrations in aquatic environments. There are, however, several 

environmental fate studies, including (835.4300) Aerobic Aquatic Metabolism, (835.1230) 

Adsorption-Desorption, (850.1730) Fish Bioaccumulation, and Analytical Methods in Water 

(835.6100) that remain as uncertainties. The registrant has submitted studies on estimation of 

Koc for bifenazate and D3598 (MRID 489295140, 48929514), aerobic aquatic metabolism, 

anaerobic soil metabolism (MRID 48929516), photodegradation in water (MRID 48929512), 

activated sludge respiration inhibition test (MRID 48929521), ready biodegradability by the 

modified sturm test (MRID 48929511), gas phase oxidation and half-life in troposphere (MRID 

48929517), quantum yield calculation (MRID 48929518), and aquatic exposure modeling 

(MRID 48929519). These data, except for the activated sludge respiration inhibition test (MRID 
Page 16 of 32 

48929521), ready biodegradability by the modified sturm test (MRID 48929511), gas phase 

oxidation and half-life in troposphere (MRID 48929517), will be reviewed for the risk 

assessment. Because D1989 is a residue of concern in both the human health and ecological risk 

assessments, submission of an aerobic aquatic metabolism study for D1989 is expected to reduce 

uncertainty of the persistence of D1989 in water. Also, an analytical method for bifenazate and 

its degradation products (D1989 and D3589) are needed. Additionally, the aerobic soil 

metabolism study (MRID 44464954) was conducted using one soil, whereas current guidance 

recommends four soils. Submission of studies evaluating the aerobic aquatic metabolism of 

D1989 and aerobic soil metabolism of bifenazate would be expected to reduce uncertainty in 

assessing exposure to bifenazate and its degradates. 

 

Bifenazate degrades to form the degradation products D-3598, D-1989, D-9472, and D- 9963. 

These degradation products are expected to exhibit ecotoxicity similar to bifenazate. 

Additionally, D1989 has been identified as a residue of concern in the human health risk 

assessment. Because exposure concentrations of bifenazate residues (bifenazate, D1989, and 

D3598, D-9472, and D-9963) will be estimated using a total toxic residues approach, cumulative

half-lives of total toxic residues in soil and water, as well as batch equilibrium coefficients of 

individual residues, are needed for exposure modeling. Aerobic soil metabolism data for D-3598 

are not needed because the cumulative half-life of TTR can be estimated from existing aerobic 

soil metabolism data for bifenazate (MRID 44464954). Because there are no adsorptiondesorption (835.1230) data for D-3598, the Koc for D-3598 will be estimated using EPIsuite 

modeling. Aerobic soil metabolism and adsorption-desorption data have been submitted for D1989.

 

Table 10, 11, and 12 identify environmental fate studies by MRID that offer data for each data

requirement, as well as study classifications and whether or not further data are needed in order 

to support risk assessment. 

Table 10. Status of Environmental Fate Data for Bifenazate

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Comments

835.2120 Hydrolysis 44464952 Supplemental No

835.2240 Aqueous 

photolysis

44464953 Acceptable No

45052308 In Review

835.2410 Soil photolysis 44522601 Acceptable No

835.4100 Aerobic soil 

metabolism

44464954 Acceptable

No

The available study only tested one soil. 

Current guidance recommends testing 

four soils. Additional soil metabolism 

tests will reduce uncertainty and help to 

refine the ecological exposure and 

drinking water exposure assessments.

835.4200 Anaerobic soil 

metabolism

(None) No Anaerobic aquatic metabolism data are 

available for bifenazate. Submission of 

anaerobic soil metabolism data are not 

expected to alter the environmental fate 

profile for bifenazate. 
Page 17 of 32 

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Comments

835.4300 Aerobic aquatic 

metabolism

(None) No Although conservative assumptions can 

be made without data, aerobic aquatic 

metabolism data for bifenazate and D1989 may help to refine exposure 

concentrations of bifenazate residues in 

aquatic environments and surface source 

drinking water. 

835.4400 Anaerobic 

aquatic 

metabolism

44522602 Supplemental No

44859702 In Review

835.1230

835.1240

Soil Column 

Leaching

44464955 Acceptable No Although quantitative estimates of 

soil:water partitioning are not possible 

from soil column leaching studies, the 

rapid degradation of bifenazate is 

expected to limit environmental 

exposure. 

835.1410 Volatility –

laboratory

(None) No Volatility study for bifenazate is not 

needed because of a low vapor pressure 

835.6100 Terrestrial field 

dissipation

45052306 In Review No

44464957 Not Acceptable 

44464958 Acceptable

Analytical 

method 

in soil

45052309 In Review

45052307 In Review

Analytical 

method in water

(None) NA Yes

850.1730 Fish 

bioconcentration

(None) NA Yes

Table 11. Status of Environmental Fate Data for the Degradate D1989 

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Comments

835.4100 Aerobic soil 

metabolism

45144002 In Review No Degradation product is expected to 

exhibit equal ecotoxicity as parent. Also, 

it is identified as a residue of concern in 

the human health risk assessment.

835.1230 Adsorption/ 

desorption

44464956 Acceptable No
Page 18 of 32 

Table 12. Status of Environmental Fate Data for the Degradate D3598 

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(MRID)

Study 

Classifications

Are data 

needed to 

conduct risk 

assessment?

Comments

835.4100 Aerobic soil 

metabolism

(None) No An aerobic soil metabolism half-life for 

D3598 was determined from the aerobic 

soil metabolism study for bifenazate 

(MRID 44464954). 

835.1230 Adsorption/ 

desorption

(None) No EPIsuite estimates of Koc will be 

considered in the exposure assessment.

7.2. Ecological Effects

Data are not available to assess chronic risk to freshwater or estuarine/marine fish, or to 

estuarine/marine invertebrates. According to the acute toxicity data for fish, bifenazate is 

classified as “highly toxic” to fish. Additionally, the chronic risk identified for other 

vertebrate taxa (birds and mammals) also suggests that there is a potential for adverse effects 

to fish on a chronic exposure basis. Therefore, there is a need for chronic toxicity data for 

fish to provide a definitive endpoint for risk assessment. The recommended toxicity test is

the Chronic Freshwater Fish Toxicity (850.1400) test. Chronic data for estuarine/marine fish 

are not required at this time because the freshwater fish data can serve as a surrogate given 

that the acute toxicity data were similar for the freshwater and estuarine/marine fish. For 

invertebrates, an acute-to-chronic ratio (ACR) was used in previous assessments to estimate 

the chronic toxicity to estuarine/marine invertebrates. When using this value as a proxy, 

chronic risk to estuarine/marine invertebrates was below the LOC. Therefore, chronic 

toxicity data are not required for estuarine/marine invertebrates at this time. 

Acceptable acute avian oral toxicity data were submitted for exposures of bobwhite quail and 

mallard duck to bifenazate, respectively; however, data are not available for passerines, 

which are required under the 40 CFR Part 158 (Oct. 26, 2007) data requirements for 

conventional pesticides (72 FR 60934; USEPA 2007a). The Part 158 data requirements 

specify that acute avian oral toxicity data be submitted for either a mallard duck or bobwhite 

quail, and for a passerine species. The exceedance of the acute and chronic LOCs based on 

the other non-passerine toxicity tests substantiates the need for these data. Therefore, an 

avian oral toxicity test conducted with a passerine (OCSPP Guideline 850.2100) is needed. 

EFED recommends that a passerine study protocol be submitted for review by the Agency 

prior to initiation of this study. Table 13 provides a summary of the status of effects data for 

Bifenazate. 

Degradate ecotoxicity data have been submitted for degradates D-1989, D-3598, and D-9472. 

These studies have not been fully reviewed at this time but provide a tentative weight of 

evidence to assume equal toxicity of the degradates and the parent bifenazate. Additional 

degradate toxicity information is not needed at this time. A summary of the available 

degradate data is provided in Appendix F. 
Page 19 of 32 

Table 13. Status of Ecological Effects Data for Bifenazate

Ecological Toxicity Data Requirements for Bifenazate

Guideline # Data Requirement Submitted 

Studies 

MRID #

Study 

Classifications

Are data 

needed for 

risk 

assessment?

Comments

850.2100 Avian acute oral LD50

(bobwhite quail) 44464928 Acceptable Yes

Acute oral toxicity 

data for a passerine 

species will be used to 

refine the screeninglevel assessment, by 

determining whether 

there are differences 

in avian species 

sensitivity to 

bifenazate. 

850-2200

Avian subacute dietary LC50

(bobwhite quail)

(mallard duck)

44464929

44464930

Acceptable 

Acceptable

No

No

850-2300

Avian reproduction

(bobwhite quail)

(mallard duck)

(mallard duck)

45052212

44872901

45144003

Supplemental

Acceptable 

Supplemental

No

No

No

850-1075

Freshwater fish acute LC50

(bluegill sunfish) 

(rainbow trout)

44464931

44464932

Acceptable 

Acceptable

No

No

850-1300

Freshwater invertebrate acute 

EC50

(daphnia) 44464933 Acceptable No

850-1075 Estuarine/marine fish acute 

LC50 (sheepshead minnow) 45052214 Acceptable No

850-

1025;1035

Estuarine/marine invertebrate 

acute EC50

(eastern oyster)

(mysid)

45052215

45052213

Acceptable 

Supplemental

No

No

850-1400 Freshwater fish early life stage

(fathead minnow) No Study Yes

Chronic toxicity data 

will be used to 

determine the 

potential for 

bifenazate to affect 

freshwater fish and 

will also serve as a 

surrogate for 

estuarine/marine fish. 

850-1300 Freshwater invertebrate life 

cycle (daphnia) 45052216 Supplemental No

850-1400 Estuarine/marine fish life cycle

(sheepshead minnow) No Study No

A study is not being 

requested at this time 

because the chronic 

freshwater fish study 

recommended above 

can serve as a 

surrogate. 
Page 20 of 32 

850-1350 Estuarine/marine invertebrate

life cycle (mysid) No Study No

A study is not being 

requested at this time 

because a surrogate is 

available using the 

acute and chronic 

freshwater 

invertebrate data and 

the acute est./marine 

invertebrate data to 

estimate chronic 

toxicity. 

850-1500 Freshwater fish full life cycle No Study Not applicable No

A study is not being 

requested at this time 

because neither of the 

following trigger

criteria were met: 1) 

estimated EECs from 

previous assessments 

for freshwater 

invertebrates were 

below the criteria of 

0.1 of the NOAEC 

(Note: a chronic fish 

early life stage study 

is not available). 2) 

studies of other 

organisms do not 

clearly indicate that 

the reproductive 

physiology of fish 

may be affected. 

850-1950 Aquatic Field Study No Study Not applicable No

81-1 Acute mammalian oral LD50 

(rat) 44464934 Acceptable No

83-3 Mammalian Developmental

(rat) No Study No

83-4 Mammalian Reproduction

(rat) 45076503 Acceptable No

850-4100 Seedling Emergence – Tier I 45052217 Acceptable No

850-4150 Vegetative Vigor - Tier I 45076502 Acceptable No

850-4400

Aquatic plant algae

(green algae)

(blue-green algae)

45052219

45052220

Acceptable 

Acceptable

No

No

850-5400 Aquatic plant acute EC50

(duckweed) 45052218 Acceptable No

850-3020 Acute honey bee contact LD50 44462315 Acceptable No

Nonguideline Acute honey bee oral LD50 No Study No

850-3030 Honey Bee Residue on Foliage 45052305 Acceptable No

850-3040 Honey Bee Field Testing for 

Pollinator No Study No
Page 21 of 32 

8. References

FIFRA Science Advisory Panel. 2008. Selected Issues Associated with the Risk Assessment 

Process for Pesticides with Persistent, Bioaccumulative, and Toxic Characteristics.

http://www.epa.gov/scipoly/sap/meetings/2008/102808_mtg.htm 

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and 

Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004. 

USEPA. 2007c. ECOTOXicology Database. Office of Research and Development National 

Health and Environmental Effects Research Laboratory’s (NHEERL’s) Mid-Continent 

Ecology Division (MED). http://cfpub.epa.gov/ecotox/. 

USEPA, 2011. BEAD Chemical Profile for Registration Review: Bifenazate (000586). U.S. 

Environmental Protection Agency, Office of Prevention, Pesticides and Toxic 

Substances, Office of Pesticide Programs, Washington DC. July 27, 2012. 

USEPA, 2012. EFED Table 1 Report. Bifenazate (000586). U.S. Environmental Protection 

Agency, Office of Prevention, Pesticides and Toxic Substances, Office of Pesticide 

Programs, Washington DC. May 8, 2012. 
Page 22 of 32 

Appendices

– Appendix A. Results of SIP

– Appendix B. Results of STIR 

– Appendix C. Ecological Effects Bibliography 

– Appendix D. Environmental Fate Bibliography 

– Appendix E. Chemical Structures

Appendix A. Results of SIP

Table 1. Inputs

Parameter Value

Chemical name Bifenazate

Solubility (in water at 25oC; mg/L) 3.76

Mammalian LD50 (mg/kg-bw) 5000

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 1.6

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 1032

Avian test species northern bobwhite quail

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 20

Bobwhite quail NOAEC (mg/kg-diet)

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird species

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.6467 0.6467

Adjusted toxicity value (mg/kg-bw) 3845.8028 1.2307

Ratio of exposure to toxicity 0.0002 0.5255

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Drinking water exposure alone is 

NOT a potential concern for 

mammals
Page 23 of 32 

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 3.0456 3.0456

Adjusted toxicity value (mg/kg-bw) 743.4833 0.9923

Ratio of exposure to acute toxicity 0.0041 3.0694

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Exposure through drinking water 

alone is a potential concern for 

birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when 

aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to 

a total exposure that has potential for effects to non-target animals.
Page 24 of 32 

Appendix B. Results of STIR

Input

Application and Chemical Information

Enter Chemical Name Bifenazate

Enter Chemical Use Crop

Is the Application a Spray? (enter y or n) y

If Spray What Type (enter ground or air) air

Enter Chemical Molecular Weight (g/mole) 300.36

Enter Chemical Vapor Pressure (mmHg) 1.00E-07

Enter Application Rate (lb a.i./acre) 0.75

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 1032

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 5000

Enter Lowest Rat Inhalation LC50 (mg/L) 4.4

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 1.62E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.03E-04

Adjusted Inhalation LD50 5.06E+00

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.01E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 7.20E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 1.42E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 1.62E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.55E-04

Adjusted Inhalation LD50 2.62E+02

Ratio of Vapor Dose to Adjusted Inhalation LD50 9.75E-07 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 9.06E-02

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 3.46E-04 Exposure not Likely Significant
Page 25 of 32 

Appendix C. Ecological Effects Bibliography 

Aquatic Animals 

Fish

Graves, W.C. and J.P. Swigert. 1997. D2341 Technical: A 96-Hour Flow-Through Acute 

Toxicity Test with the Bluegill (Lepomis macrochirus). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-101. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 444649-31 

Graves, W.C. and J.P. Swigert. 1997. D2341 Technical: A 96-Hour Flow-Through Acute 

Toxicity Test with the Rainbow trout (Oncorhynchus mykiss). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-102. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 444649-32 

Graves, W.C., and H.O. Kruger. 1999. D2341 Technical (bifenazate): A 96 hour flow-through 

acute toxicity test with the Sheepshead minnow (Cyprinodon variegates). Study performed by 

Wildlife International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 

117A-104. Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 

06524. 

MRID 450522-14 

Invertebrates

Drottar, K.R., and H. O. Krueger. 1999. D2341 Technical (bifenazate): A Flow-Through Life 

Cycle Toxicity Test with the Cladoceran (Daphnia magna). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-107. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-16 

Graves, W.C. and J.P. Swigert. 1997. D2341 Technical: A 48-Hour Flow-Through Acute 

Toxicity Test with the Cladoceran (Daphnia magna). Study performed by Wildlife International 

Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-103A. Study 

sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 444649-33 

 

Graves, W.C., and H. O. Krueger. 1999. D2341 Technical (bifenazate): A 96-hour Shell 

Deposition Test with the Eastern Oyster (Crassostrea virginica). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-106. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-15 

Graves, W.C., and H. O. Krueger. 1999. A 96 hour Flow-Through Acute Toxicity Test with the 

Saltwater Mysid (Mysidopsis bahia. Study performed by Wildlife International Ltd., 8598 

Commerce Drive, Easton, Maryland 21601. Study report # 117A-105. Study sponsored by 

Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-13 
Page 26 of 32 

Plants

Drottar, K.R., and H. O. Krueger. 1999. D2341 Technical (bifenazate): A 7-day Toxicity Test 

with Duckweed (Lemna gibba G3). Study performed by Wildlife International Ltd., 8598 

Commerce Drive, Easton, Maryland 21601. Study report # 117A-113. Study sponsored by 

Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-18 

Drottar, K.R., and H. O. Krueger. 1999. D2341 Technical (Bifenazate): a 96-hour Toxicity Test 

with the Freshwater Alga (Selenastrum capricornutum). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-111. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-19 

Drottar, K.R., and H. O. Krueger. 1999. D2341 Technical (Bifenazate): A 96-hour Toxicity 

Test with the Freshwater Blue-green Alga (Anabaena flos-aquae). Study performed by Wildlife 

International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 117A-109A. 

Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450522-20 

Terrestrial Animals 

Birds

Pedersen, Carol A. 1996. Acute Avian Oral Toxicity (LD50) Study with D2341 Technical in 

Bobwhite Quail. Study performed by Bio-life® Associates, Ltd., Neillsville, WI. Study ID 109-

025-03. Study sponsored by Uniroyal Chemical Company, Inc., Bethany, CT 06524-3402. 

MRID 444649-28 

Pedersen C.A. and B.R. Helsten. 1997. Acute Avian Dietary Toxicity (LC50) Study with D2341 

Technical in Bobwhite Quail. Study performed by Bio-life® Associates, Ltd., Neillsville, WI. 

Study ID 109-023-01. Study sponsored by Uniroyal Chemical Company, Inc., Bethany, CT 

06524-3402. MRID 444649-29 

Pedersen, C. A. and B.R. Helsten. 1997. Acute Avian Dietary Toxicity (LC50) Study with 

D2341 Technical in Mallard Ducklings. Study performed by Bio-Life Associates, Ltd., 

Neillsville, WI. Study ID 109-024-02. Study sponsored by Uniroyal Chemical Company, Inc., 

Bethany, CT 06524-3402. MRID 444649-30 

Pedersen, Carol A. 1999. Avian Reproductive Toxicity Study with D2341 Technical in 

Bobwhite Quail. Study performed by Bio-life® Associates, Ltd., Neillsville, WI. Study ID 109-

031-07. Study sponsored by Uniroyal Chemical Company, Inc., Bethany, CT 06524-3402. 

MRID 450522-12 

Pedersen, Carol A. 1999. Avian Reproductive Toxicity Study with D2341 Technical in Mallard 

Duck. Study performed by Bio-life® Associates, Ltd., Neillsville, WI. Study ID 109-031-08. 

Study sponsored by Uniroyal Chemical Company, Inc., Bethany, CT 06524-3402. MRID 

448729-01 
Page 27 of 32 

Frey, L.T. et al., 2000. D2341 Technical.: A Reproduction Study with the Mallard. Study 

performed by Wildlife International Ltd., 8598 Commerce Drive, Easton, MD 21601. Study ID 

117-174. Study sponsored by Uniroyal Chemical Company, Inc., Bethany, CT 06524-3402. 

MRID 451440-03. 

Mammals

Hoffman, G. 1996. Acute oral toxicity study with D2341 Technical in rats. Huntingdon Life 

Sciences, P.O. Box 2360, Mettlers Road, East Millstone, NJ 08875-2360. Study No. 95-1199, 

August 8, 1996. MRID 444649-34 

Schardein, J.L. 1999. A Two-generation Reproductive Toxicity Study of D2341 in Rats. WIL 

Research Laboratories, Inc., Ashland, OH. Laboratory Study No.: WIL-155039. March 10, 

1999. MRID 450765-03 

Beneficial Insects

Palmer, S.J. and J.B. Beavers. 1997. D2341 Technical: An Acute Contact Toxicity Study with 

the Honey Bee. Study performed by Wildlife International Ltd., 8598 Commerce Drive, Easton, 

MD 21601. Study ID 117-170. Study sponsored by Uniroyal Chemical Company, Inc., 

Bethany, CT 06524-3402. MRID 444623-15 

 

Hummel, R.L. 1999. Final Report for the Evaluation of Toxicity of Residues of Bifenazate 

(UCC D2341 50 WP) on Alfalfa to Honey Bees (Apis mellifera). Study performed by Landis 

International, Inc., P.O. Box 5126, 3185 Madison Highway, 

Valdosta, GA 31603-5126. Laboratory report # 1l52lA002. Study sponsored by Uniroyal 

Chemical Company, Inc. 74 Amity Road, Bethany, CT 06524. 

MRID 450523-05 

Plants

Porch, J.R. and H. Krueger. 1999. UCC-D2341-50W: A Toxicity Test to Determine the Effects 

of the Test Substance on Seedling Emergence of Ten Species of Plants. Study performed by 

Wildlife International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 

117-172. Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 

06524. 

MRID 450522-17 

Porch, J.R. and H. Krueger. 1999. UCC-D2341-50W: A Toxicity Test to Determine the Effects 

of the Test Substance on Vegetative Vigor of Ten Species of Plants. Study performed by 

Wildlife International Ltd., 8598 Commerce Drive, Easton, Maryland 21601. Study report # 

117-173. Study sponsored by Uniroyal Chemical Company, Inc. 74 Amity Road, Bethany, CT 

06524. 

MRID 450765-02 
Page 28 of 32 

Appendix D. Environmental Fate Bibliography 

Abiotic Hydrolysis (835.2120) 

Shah, J. F. 1997. A hydrolysis study of [14C]D2341. Laboratory Project ID: 95-0006. 

Unpublished study performed by Ricerca, Inc., Painesville, OH; and submitted by Uniroyal 

Chemical Co., Inc., Middlebury, CT. MRID 444649-52. 

Findak, D.; DiFrancesco, D; Shah, J. 1999. A hydrolysis study of D2341: Lab Project 

Number:6337-95-0006-EF-001:95—0006. Unpublished study prepared by Ricerca. MRID 

44796701. 

Direct Photolysis in Water (835.2240) 

Shah, J. 1997. Aqueous Photolysis of [14C]D2341 at pH 5. Laboratory Project ID: 95-0032. 

Unpublished study performed by Ricerca, Inc., Painesville, OH; and submitted by Uniroyal 

Chemical Co., Inc., Middlebury, CT.MRID 444649-53. 

Shah, J. 1998. Photolysis of [14C]D2341: Lab Project Number:6394-95-0217-EF-001:95-0217-

EF-001:95-0217:96092. Unpublished study prepared by Ricerca. MRID 45052308. 

Direct Photolysis in Soil (835.2410) 

Shah, J. F. 1997. Photolysis of [14C]D2341 on soil. Laboratory Project ID: 96-0001. 

Unpublished study performed by Ricera, Inc., Painesville, OH; and submitted by Uniroyal 

Chemical Co., Inc., Middlebury, CT. 

MRID 445226-01 

Aerobic Soil Metabolism (835.4100) 

Lee, D. Y., N. R. Lentz, B. M. McCall and D. N. Pellack. 1996. Aerobic soil metabolism of 

[

14C]D2341. Uniroyal Project No: 95233. Unpublished study performed by Ricerca, Inc., 

Painesville, OH; and submitted by Uniroyal Chemical Co., Inc., Middlebury, CT. 

MRID 444649-54. 

Nag, J.K. and R.R, Regis. 2000. Aerobic soil metabolism of 14C-4-methoxybiphenyl. Study No. 

99009. Unpublished study performed and submitted by Uniroyal Chemical Company, 

Registration Chemistry Section, Crop Protection R & D, Middlebury, CT. MRID 45144002. 

Anaerobic Aquatic Metabolism (835.4400) 

Lentz, N. R. 1998. Anaerobic aquatic metabolism of [14C]D2341. Laboratory Project ID: 95-

0115. Unpublished study performed by Ricerca, Inc., Painesville, OH; and submitted by 

Uniroyal Chemical Co., Inc., Middlebury, CT.MRID 445226-02. 

Lentz, N. 1998. Anaerobic Aquatic Metabolism of 14C]D2341: Lab Project Number: 95235:95-

0115:6492-95-0115-EF-001. Unpublished study prepared by Ricerca, Inc. MRID 44859702. 
Page 29 of 32 

Leaching – Soil Adsorption/Desorption (835.1230/835.1240) 

Huhtanen, C. F. 1997. Soil adsorption and desorption of [14C]D1989. Laboratory Project ID: 

96-0056. Unpublished study performed by Ricerca, Inc., Painesville, OH; and submitted by 

Uniroyal Chemical Co., Middlebury, CT. MRID 444649-56. 

Hatzenbeler, C. J. 1997. Soil column leaching study of [14C]D2341. Project ID No.: 96-0024. 

Unpublished study performed by Ricerca, Inc., Painesville, OH; and submitted by Uniroyal 

Chemical Co., Inc., Middlebury, CT. MRID 444649-55. 

Terrestrial Field Dissipation (835.6100) 

Jablonski, J. E. 1997. Terrestrial field dissipation of D2341 applied to bare ground in North 

Carolina. Laboratory Study No.: 96-0034. Laboratory Project ID: 6737. Unpublished study 

performed by American Agricultural Services, Inc., Cary, NC (in-life phase); and Ricerca, Inc., 

Painesville, OH (analytical phase); and submitted by Uniroyal Chemical Co., Inc., Middlebury, 

CT. MRID 444649-57. 

Jablonski, J. E. and R. G. Kenyon. 1997. Terrestrial field dissipation of D2341 applied to bare 

ground in Washington. Laboratory Study No.: 96-0035. Laboratory Project ID: 6739. 

Unpublished study performed by Qualls Agricultural Labs, Inc., Ephrata, WA (in-life phase), 

and Ricerca, Inc., Painesville, OH (analytical phase); and submitted by Uniroyal Chemical Co., 

Inc., Middlebury, CT. MRID 444649-58. 

Jablonski, J. 1998. Terrestrial field dissipation of D2341 applied to bareground in California: Lab 

Project No: 6738-96-0033-CR-001:96-003:6738. Unpublished study prepared by Ricerca, Inc. 

MRID 45052306. 

Jablonski, J. 1999. Stability of D2341 and D1989 and D3598 in soil during freezer storage: Lab 

Project No: 96-0036:6743-96-0036-CR-001:6743. Unpublished study prepared by Ricerca, Inc. 

MRID 45052307. 

Jablonski, J. 1999. Analytical method for analysis of D2341, D1989 and D3598 in soil: Lab 

Project No: 6616-96-0269-CR-001. Unpublished study prepared by Ricerca, Inc. MRID 

45052308. 
Page 30 of 32 

Appendix E. Chemical Structures
Page 31 of 32 

Appendix F. Submitted Ecological Toxicity Data for Bifenazate Degradates D1989, D-3598, and D9472 in Comparison to the Parent 

Ecological Toxicity Data for D-1989

Guideline 

# 

Data 

Requirement

Submitted 

Studies 

MRID #

Study 

Classification

Tentative 

Endpoint 

(Data not fully 

reviewed)

Parent for 

Comparison 

850-1300 

Freshwater 

invertebrate 

acute EC50 

(Daphnia 

magna)

45141801 In Review EC50 :0.25 mg 

/L

EC50: 0.50 mg 

a.i./L

Nonguideline Acute 14-day 

Earthworm 

(Eisenia fetida)

47622301 Supplemental 

LC50: 66.7 

mg./kg dry soil 

(Data reviewed 

but 

supplemental) 

MRID 

(48929520) is in 

review. 

Tentative 

endpoint: LC50

>1250 mg 

a.i./kg dry soil

Ecological Toxicity Data for D-3598

Guideline 

# 

Data 

Requirement

Submitted 

Studies 

MRID #

Study 

Classification

Tentative 

Endpoint 

(Data not fully 

reviewed)

Parent for 

Comparison 

850-1075 

Freshwater fish 

acute LC50 

(Oncorhynchus 

mykiss)

48929504 In review 96 hr LC50: 

0.044 mg /L 

96 hr LC50: 0.78 

mg a.i./L 

850-1300 

Freshwater 

invertebrate 

acute EC50 

(Daphnia 

magna)

48929503 In review 48 hr EC50: 

0.051 mg/L 

48 hour EC50 of 

0.50 mg a.i./L 

850-4400 Aquatic plant 

(Selenastrum 

capricornutum) 

48929502 In review

96 hr EC50: 0.78 

mg/L (cell 

density) 

NOAEC: 0.38 

mg/L

96 hr EC50: 0.89 

mg a.i./L 

NOAEC: 0.25 

mg a.i./L 

Nonguideline Acute 14-day 

Earthworm 

(Eisenia fetida)

48929501 In review LC50: 185.4 mg 

a.i./kg dry soil

MRID 

(48929520) is in 

review. 

Tentative 

endpoint: LC50 

>1250 mg 

a.i./kg dry soil
Page 32 of 32 

Ecological Toxicity Data for D-9472

Guideline 

# 

Data 

Requirement

Submitted 

Studies 

MRID #

Study 

Classification

Tentative 

Endpoint 

(Data not 

fully 

reviewed)

Parent for 

Comparison 

850-1300

Freshwater 

invertebrate 

acute EC50 

(Daphnia 

magna)

48929508 In review 48 hr. EC50: 

0.78 mg/L 

EC50: 0.50 mg 

a.i./L

850-4400

Aquatic plant 

(Scenedesmus 

subspicatus) 

48929509 In review

76 hr EC50 : 

0.71 mg/L 

NOAEC: 0.11 

mg/L

96 hr EC50: 0.89 

mg a.i./L 

(Selenastrum 

capricornutum)

850-1075

Freshwater fish 

acute LC50 

(Lepomis 

macrochirus)

48929506 In review 96 hr EC50: 

0.23 mg/L 

96 hr EC50 : 0.58 

mg a.i./L