Page 2 of 118 

 

Preliminary Environmental Fate and Ecological Risk 

Assessment for the Registration Review of Flufenacet 

(4' – fluoro – N – isopropyl – 2 - [5 - (trifluoromethyl) - 1,3,4 – thiadiazol – 2 -yloxy] acetanilide 

Flufenacet (CAS 142459-58-3)

Prepared by:

Geoffrey Sinclair, Biologist 

Gabe Rothman, Environmental Scientist 

U. S. Environmental Protection Agency 

Office of Pesticide Programs 

Environmental Fate and Effects Division

Environmental Risk Branch V 

1200 Pennsylvania Ave., NW 

Mail Code 7507P 

Washington, DC 20460

Reviewed by: 

Mah Shamim, Branch Chief
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Table of Contents

1. Executive Summary ................................................................................................................ 4

2. Use Characterization ............................................................................................................... 6

3. Exposure Characterization ...................................................................................................... 6

3.1 Environmental Fate and Transport Summary .................................................................. 6

3.2 Exposure Pathways .......................................................................................................... 8

3.3 Aquatic Exposure Analysis ............................................................................................ 10

3.4 Terrestrial Exposure Analysis ........................................................................................ 14

4. Ecological Effects Characterization ...................................................................................... 21

4.1 Aquatic Effects Summary .............................................................................................. 21

4.2 Terrestrial Effects Summary .......................................................................................... 25

4.3 Degradate toxicity .......................................................................................................... 28

4.4 ECOTOX Open Literature ............................................................................................. 31

4.5 Review of Incident Data ................................................................................................. 31

5. Risk Characterization ............................................................................................................ 32

5.1. Risk Estimation .............................................................................................................. 33

5.2. Risk Description ............................................................................................................. 42

5.2.1 Risk to Non-Target Aquatic Organisms ..................................................................... 42

5.2.2 Risk to Non-Target Terrestrial Organisms ................................................................. 47

5.2.3 Uncertainties, Assumptions, and Limitations ............................................................. 55

6. Endocrine Disruptor Screening Program .............................................................................. 57

7. Federally Threatened and Endangered (Listed) Species of Concern .................................... 58

Conclusions ................................................................................................................................... 60

8. References ............................................................................................................................. 63

Appendix A. Environmental Fate and Ecological Effects Data for Flufenacet ........................... 65

Appendix B. Status of Environmental Fate and Ecological Effects Studies for Flufenacet ........ 80

Appendix C. Formation and Decline of Flufenacet Metabolites ................................................. 84

Appendix D. Sample SWCC and PRZM-GW Files .................................................................. 104

Appendix E. Sample TREX Files .............................................................................................. 108

Appendix F. Sample KABAM Files .......................................................................................... 112

Appendix G. Risk Quotient Method .......................................................................................... 117

 
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1. Executive Summary

Scope and Rationale for Registration Review Risk Assessment 

This document contains the environmental fate and ecological risk assessments for the registered 

uses of the chemical flufenacet. This risk assessment is intended to address the potential ecological 

risks associated with the registered uses of flufenacet and is intended to update but not replicate 

previous assessments. Previous assessments are discussed in the flufenacet problem formulation 

(DP D382416). 

Since these assessments, no new environmental fate data has been submitted that would impact 

the ecological risk assessment. However, this assessment evaluates exposure from both parent 

flufenacet and its thiadone degradate (hereafter thiadone) in aquatic environments for the first time. 

Thiadone forms in water at levels up to 84.3 percent of applied 55 days after application. Refer to 

Section 4.3 for further justification. 

Six new ecological toxicity studies have been submitted in response to the data requested during 

the problem formulation stage including parent flufenacet chronic toxicity to sheepshead minnow 

(MRID No. 49244201), acute toxicity to mysid shrimp (MRID No. 49119001), chronic toxicity to 

mysid shrimp (MRID No. 49119002), acute toxicity to a passerine species (MRID No. 49244202), 

and mallard duck (MRID No. 44246801). Furthermore, new toxicity data for vascular aquatic 

plant (Duckweed) and non-vascular plant Selenastrum capricornutum were submitted for the 

flufenacet thiadone degradate (MRID No. 48897612 and 45796115 respectively). While these 

studies have been reviewed and considered in this risk assessment, there are also seven studies 

submitted currently being reviewed which examine the toxicity of flufenacet in its form with coformulated products on both vegetative vigor (Guideline number 850.4150) and seedling 

emergence (Guideline number 850.4100) of terrestrial plant species. These studies examine 

Flufenacet SC500 (MRIDs 48897605 and 48897609), Flufenacet & Isoxaflutole WG 58 (MRIDs 

48897606 and 48897610), Flufenacet and Isoxaflutole SC 480 (MRIDs 48897607 and 48897611), 

and Axiom 68DF (MRID 48897688) products. Due to time constraints, these studies are still being 

reviewed and have not been considered in this risk assessment as of this time, but will be in the 

future. 

Flufenacet Current Registered Uses 

Flufenacet is a pre-emergent herbicide and is applied as a broadcast surface spray, banded surface 

spray, or is incorporated into soil for all uses. Current labels allow the use of flufenacet on corn 

for silage, sweet corn, field corn, grasses grown for seed, soybeans, triticale and wheat. The 

maximum labeled single application rate for flufenacet is 0.8019 lbs a.i./A for corn for silage, field 

corn, and sweet corn, 0.4420 lbs a.i./A for grasses grown for seed, 0.4644 lbs. a.i./A for soybeans, 

and 0.3400 lbs a.i./A for both triticale and wheat, with maximum crop cycle applications specified 

the same for each use. 

Flufenacet belongs to a class of compounds called the oxyacetamides that act by inhibiting mitosis 

and cell division (http://www.plantprotection.org/hrac/MOA.html). Like other acetamide 
Page 5 of 118 

herbicides, flufenacet inhibits root and shoot growth of germinating seeds and very small emerged 

seedlings. 

Environmental Fate and Exposure Summary 

Flufenacet residues have the ability to reach nearby water bodies equivalently in a dissolved state 

via runoff and sorbed state via erosion based on its soil organic carbon – water partition coefficient 

209 – 762 mL/g and solubility value of 56 mg/L. The primary degradation of flufenacet occurs 

with biodegradation in aerobic soil and aerobic water environments via cleavage of the ether 

linkage (see Figures 1 and 2). It is moderately persistent in both soil and water environments 

with half-lives ranging between 23.1 – 63.6 days in aerobic soil environments and 18 – 77 days in 

aerobic aquatic environments. The toxic degradate of concern, the thiadone degradate of 

flufenacet, forms in water bodies at levels of up to 84.3 percent of applied where it is persistent 

with half-lives ranging between 160 – 303 days in aerobic and anaerobic environments. Thiadone 

more readily biodegrades in top soil with half-lives ranging between 2.0 – 2.8 days in aerobic 

environments, and therefore is not likely to be available for runoff in large quantities as compared 

to quantities at which it is observed to form in water bodies. 

While flufenacet is applied prior to the emergence of crops, exposure to flufenacet residues is 

possible for terrestrial organisms. Insectivores and granivores may ingest food items on fields 

treated with flufenacet residues. Exposure is further plausible given flufenacet’s moderate 

persistence in terrestrial environments (half-lives ranging between 23.1 – 63.6 days). 

Ecological Effects Summary and Risk Conclusions 

When estimates of flufenacet exposure in terrestrial and aquatic environments are compared to the 

available ecotoxicity data, the results of the screening-level assessment indicate a potential for risk 

above the level of concern to both aquatic and terrestrial taxa for proposed uses of flufenacet. 

Refer to Table 30 and Table 31 in the Conclusions Section of this document (Section 5) which 

present the risks of concerns found for all aquatic and terrestrial organisms, respectively, resulting 

from the proposed uses of flufenacet specified by crop. 

Flufenacet is moderately toxic to aquatic animals (invertebrates and fish). In general, risk 

quotients for aquatic organisms are calculated considering a single total toxic residue estimated 

exposure concentration (EEC) including flufenacet and its thiadone degradate in the surface water 

column for each crop. Risk concerns exist for only aquatic plants for all uses (non-listed and listed 

RQs ranging between 1.6-60.2) but not for any aquatic animal taxa for all uses. Risks to aquatic 

plants are predominantly driven by runoff as opposed to spray drift as risk conclusions largely do 

not change when removing the contribution of spray drift. Given the risks identified for aquatic 

plants, separate EECs of flufenacet and thiadone are presented. Overall, risks remain to aquatic 

plants upon further examination when separating the EECs (see Section 5.1 and Table 17 for 

further explanation). 

For terrestrial wildlife, flufenacet is slightly toxic to mammals on an acute basis, slightly to highly 

toxic to birds on an acute basis, practically non-toxic to terrestrial invertebrates on an acute contact 

basis. Since the time of the problem formulation, the Agency now also requires acute and chronic 
Page 6 of 118 

toxicity studies submitted for larval bees and chronic feeding studies for adult bees. While 

flufenacet was classified as practically non-toxic to honey bees on an acute contact basis, the 

impacts of flufenacet on chronic exposure to adults or on the biology of larvae currently constitute 

an uncertainty in this assessment. 

Acute avian risk to threatened and endangered birds was identified for every use of flufenacet 

(RQs as high as 0.41) and chronic avian risk was identified for every use except wheat and triticale 

(RQs as high as 2.19). Acute risk to endangered mammals was identified for corn uses (RQs as 

high as 0.14) while chronic mammalian risk was identified for every use (RQs as high as 7.3). The 

most direct risks to animals and birds with pre-emergent flufenacet applications may occur due to 

ingestion of arthropods and seeds containing applied flufenacet residues on the field. However, 

risks may also occur with short grass and non-crop broadleaf plants off the treated field given 

runoff of flufenacet residues from the treated field. The extent of exposure under the runoff 

scenario is uncertain given the nature of terrestrial exposure estimates available on the treated field 

only. 

Larger risk concerns associated with flufenacet uses are identified with terrestrial plants. 

Terrestrial plant risk was identified for every use of flufenacet (non-listed and listed RQs ranging 

between 0.2–25.5), and both runoff and spray drift processes contribute to the overall risk. Buffers 

required to mitigate the spray drift to terrestrial plants ranged from 3 feet to 988 feet depending on 

application method and application rate (Tables 26 – 29). 

2. Use Characterization 

Current labels allow the usage of flufenacet on corn for silage, sweet corn, field corn, grasses 

grown for seed, soybeans, triticale and wheat. Flufenacet maximum application rates are 0.8019 

lbs a.i./A for corn for silage, field corn, and sweet corn, , 0.442 lbs a.i./A for grasses grown for 

seed, 0.4644 lbs. a.i./A for soybeans, and 0.34 lbs a.i./A for both triticale and wheat. These 

maximum application rates are specified as a single or crop-cycle basis. Flufenacet is only used 

as a pre-emergent herbicide and is applied as a broadcast surface spray, banded surface spray, or 

via soil incorporated methods for all uses. 

The screening-level use assessment (SLUA) estimates of agricultural uses of flufenacet indicate 

that usage on corn alone accounts for roughly 88% of the total use (USEPA 2010). Usage of 

flufenacet is applied on at most 5% of the total crop area treated for agricultural uses. Flufenacet 

usage is concentrated in the corn and soybean belt of the Midwest, North Carolina, Southern High 

Plains, and Oregon. 

3. Exposure Characterization 

3.1 Environmental Fate and Transport Summary 

This document presents a summary on the fate and transport behavior for both flufenacet and its 

thiadone degradate in the environment given that there is a complete dataset of fate studies for 

both constituents. Section 3.C of the original problem formulation document (DP Barcode: 

D382416; EPA 2011) can be referred to for further details. No new environmental fate studies 
Page 7 of 118 

have been submitted since the original problem formulation with the exception of environmental 

chemistry methods (ECMs) and independent laboratory validations (ILVs) in soil and water for 

flufenacet and its thiadone, alcohol, oxalate, and sulfonic acid degradates. The table summarizing 

the quality classifications for each study is provided in Appendix B. 

Flufenacet can exist both in the dissolved phase and sorbed phase in soil at equivalent levels, with 

Koc values ranging from 209 – 762 mL/goc (MRID No. 43441137) and aqueous solubility value of 

56 mg/L. Therefore, flufenacet has the ability to reach ground water via leaching processes 

and aquatic environments via runoff and erosion processes. Flufenacet will not likely 

predominately exist in the vapor-phase given its vapor pressure of 2.11 x 10-7 torr and Henry’s 

Law Constant of 2.12 x 10-8 atm•m3/mol. 

Flufenacet is moderately persistent in soil and water with primary decline occurring due to 

biodegradation in aerobic environments over time. Flufenacet half-lives range from 23.1 days – 

63.6 days in aerobic soil environments (MRID Nos. 43441141, 43441135, and 43850058) and 18 

– 77 days in aerobic aquatic environments (MRID Nos. 45796112 and 44580203). Flufenacet is 

stable in anaerobic soil environments (MRID No. 43850059) and persistent in anaerobic aquatic 

systems with a half-life of 492 days (MRID No. 43850060). Flufenacet is stable due to abiotic 

degradation processes including hydrolysis and photolysis in water and soil (MRID Nos. 

43441134, 43850056, and 43850057). The overall moderate persistence of flufenacet in the 

environment is verified from field dissipation studies (MRID Nos. 43850062,43850063). The 

molecular structure of flufenacet is shown in in Figure 1 below. 

Figure 1. Molecular structure for flufenacet. 

In general, flufenacet breaks down in both soil and water by separating into anilide and thiadone 

components via cleavage of the ether linkage (MRID Nos. 43441141, 43441135, 43850058, 

45796112, 44580203). The entire thiadone group (right hand side of the parent molecule in Figure 

1) remains completely intact and is persistent in aerobic and anaerobic aquatic environments with 

half-lives ranging between 160 - 303 days (MRID Nos. 4579110 and 45796111), but is more labile 

in aerobic soil environments with half-lives ranging 2.0 – 2.8 days (MRID No. 45796109). In both 

soil and water, the anilide group (left hand side of the parent molecule) exhibits more complex 

serial degradation processes to alcohol, methylsulfoxide, oxylate, and sulfonic acid by-products. 

The anilide by-products described above are all detected at major levels (greater than 10 percent 

of applied) in the aerobic soil, anaerobic soil, aerobic aquatic, and anaerobic aquatic metabolism 

laboratory studies (MRID Nos. 43441141, 43441135, 43850058, 45796112, and 44580203). 

However, the thiadone degradate is only detected at major levels in water likely given its high 

persistence in aerobic and anaerobic aquatic environments and more labile nature in aerobic soil 

environments (MRID Nos. 43441141, 43441135, 43850058, 45796112, 44580203, 4579110, 

45796111, and 45796109). Refer to Tables C-1 and C-2 in Appendix C for detailed information 

on the formation and decline for all of the degradates in soil and water. 
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Both the thiadone degradate and flufenacet have been identified as the residues of concern in this 

ecological risk assessment (see Section 4.3 for a complete discussion). Given thiadone’s highly 

labile nature in soil, substantial translocation of the thiadone degradate via leaching to ground 

water and runoff to aquatic environments is not likely. However, the thiadone degradate is 

expected to form at high levels from biodegradation of flufenacet residues which reach 

surface water. Once the thiadone degradate forms, it is likely to be persistent in water for a long 

duration as indicated by its half-life of 160 – 303 days in aerobic and anaerobic aquatic 

environments. It should be noted that as compared to flufenacet, a more substantial portion of the 

thiadone degradate material would likely remain in the water column rather than sorbed to 

sediment given its Koc values in the range of 29 – 58 (MRID No. 43441140). The thiadone 

degradate in water is not anticipated to exist in the vapor-phase at large levels given its Henry’s 

Law Constant of 1.2 x 10-7 atm•m3

/mol. The molecular structure of the thiadone degradate is 

shown in Figure 2. 

Figure 2. Molecular structure for the flufenacet thiadone degradate. 

3.2 Exposure Pathways 

Flufenacet and its thiadone degradate are considered to be the primary stressors for aquatic 

organisms in this risk assessment. In aquatic environments, the thiadone degradate is formed at 

major levels in aerobic water environments of up to 84.3% of applied 55 days after application due 

to cleavage of the parent flufenacet molecule as a result of biodegradation in aerobic environments. 

Since the thiadone degradate is generally more mobile than the parent, the environmental fate 

characteristics specific to flufenacet and thiadone will be incorporated separately into the aquatic 

exposure analysis using formation-decline approach. In this approach, the total residue 

concentration that is predicted reflects the decline of the parent and the subsequent formation and 

decline of the degradate as stipulated by their unique fate properties. It should be noted that while 

the unique fate characteristics of thiadone will be considered separately in aquatic exposure 

estimation, aquatic EECs will initially be presented as a total toxic residue, and refined if risk is 

indicated to show fluefenacet and thiadone specific EECs. Refer to Section 3.1 in this document 

or Section 3.C in the problem formulation for a further description of the behavior of the thiadone 

degradate in the environment. . Furthermore, refer to Appendix C on the formation of thiadone 

and other major degradates., and Table 13 of Section 4.3 supporting the findings on the expected 

relative toxicity of the thiadone degradate and all other major degradates to parent flufenacet. In 

the terrestrial environment, only parent flufenacet is considered the primary stressor for 

terrestrial organisms since thiadone does not form at major levels in soil 

The identification of relevant environmental exposure pathways to flufenacet applications for this 
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risk assessment evaluating impact to non-target organisms are further discussed in detail below: 

 Aquatic Exposure: Flufenacet’s potential to be transported to water bodies and aquatic 

habitats in both a dissolved state in runoff or sorbed state to erodible soil particles is a relevant 

pathway associated with flufenacet applications. The moderate persistence of flufenacet in 

the environment lends itself to being available to runoff and erosion off-site transport 

processes. Furthermore, off-site spray drift deposition of flufenacet to water bodies nearby 

applications may also adversely impact aquatic organisms. In addition, once flufenacet 

reaches a water body, there is the potential for its thiadone degradate to form. Freshwater 

and estuarine marine fish and invertebrates as well as aquatic plants in the water column may 

be impacted. Limited exposure is expected occur with benthic and sediment-dwelling 

organisms given flufenacet is not expected to build up in sediment and organic matter given 

its measured Koc in the range between 209 – 762 mL/g and log Kow of 3.2. Refer to the 

problem formulation document for further details (DP Barcode: D382416; EPA 2011). 

 Dietary Exposure: Direct dietary exposure to non-target terrestrial organisms (birds and 

mammals) is possible with the application of flufenacet. While flufenacet is applied prior to 

the emergence of crops, insectivores and granivores may ingest food items possessing the 

flufenacet residues. Dietary exposure is also possible given the moderate persistence of 

flufenacet in the terrestrial environment.

Furthermore, indirect dietary exposure may result from aquatic exposure to fish (discussed 

above). Therefore, piscivorous birds and mammals feeding on contaminated fish may 

potentially be exposed. Bioaccumulation potential of flufenacet residues is possible in fish 

given flufenacet’s moderately high Log Kow value of 3.20 and moderately high steady-state 

BCF values in fish of up to 103X (MRID Nos. 43441127 and 43441139). 

 Terrestrial plants: Given the herbicidal characteristics of flufenacet, adverse impacts to 

non-target terrestrial plants are expected. Exposure may occur via the runoff of residues offsite from treated fields to adjacent lands covered with non-targeted vegetation. Furthermore, 

off-site deposition of flufenacet due to spray drift may also adversely impact non-target 

terrestrial plants. Another potential route of exposure that exists to terrestrial plants includes 

application of irrigation water to non-target plants and crops from ground and surface water 

sources possessing flufenacet residues. This is possible given its moderate persistence in the 

environment and ability to move to surface water via runoff and ground water via leaching.

 Terrestrial invertebrates: Dietary and contact exposure to terrestrial invertebrates are 

possible pathways with flufenacet applications. Crops on fields pre-treated with flufenacet 

may potentially uptake flufenacet residues. Crops containing flufenacet residues may 

potentially attract terrestrial invertebrates (e.g., beneficial insects) resulting in dietary and 

contact exposure.

Drinking water and inhalation exposure to terrestrial animals are not expected to be of 

concern as verified by results of the Screening Imbibition Program (SIP version 1.0, 6/15/2010) 

and the Screening Tool for Inhalation Risk (STIR version 1.0; 11/23/2010), respectively. SIP is 

available publically at: http://www.epa.gov/oppefed1/models/terrestrial/sip/sip_user_guide.html. 
Page 10 of 118 

STIR may be accessed on-line at: 

http://www.epa.gov/oppefed1/models/terrestrial/stir/stir_user_guide.html. The analyses using 

SIP and STIR are presented in the problem formulation document (DP Barcode: D382416; EPA 

2011). 

Risk hypotheses are specific assumptions about potential adverse effects (i.e., changes in 

assessment endpoints) and may be based on theory and logic, empirical data, mathematical models, 

or probability models (EPA 1998). For flufenacet, the following ecological risk hypothesis is 

being employed for this risk assessment:

Given the proposed ground and aerial foliar spray uses of flufenacet and its environmental 

fate properties, there is a likelihood of exposure with flufenacet and its thiadone degradate 

to non-target aquatic organisms, and with flufenacet alone for terrestrial organsims.

When used in accordance with the label, flufenacet results in potential adverse effects upon 

the survival, growth, and reproduction of non-target terrestrial and aquatic organisms. 

3.3 Aquatic Exposure Analysis 

Aquatic Exposure Estimation Modeling 

Estimated exposure concentrations for aquatic animals and plants in surface waters for labeled 

flufenacet applications are estimated using The Surface Water Concentration Calculator interface 

(SWCC version 1.21, dated February 19, 2015). Combined exposures from parent flufenacet and 

its thiadone degradate are presented using the formation-decline method accounting for the 

presence of both compounds simultaneously in the environment over time. The formation-decline 

method is selected for this analysis since thiadone is more mobile than parent flufenacet. Refer to 

beginning of Section 3.2 for further information on the formation-decline method. The SWCC is 

available on-line at: http://www.epa.gov/oppefed1/models/water/#swcc. 

 

In this assessment, exposure estimates for each of the current crop uses presented represent the 

highest and most vulnerable exposure for flufenacet use sites across the country which its used 

including the Midwestern Corn Belt, Southern Plains, North Carolina, and Oregon. For all of the 

agricultural crop uses, broadcast surface spray applications to bare ground are evaluated since this 

is the conservative application scenario for runoff. The fate parameters and use-specific input 

parameters for the SWCC surface water modeling are shown in Table 1 and Table 2, respectively. 

The EECs of flufenacet and its thiadone degradate in surface water are shown for aerial and ground 

applications in Table 3. The SWCC output files are provided in Appendix C.

Table 1. SWCC input parameter values used for surface water aquatic exposure estimation with 

flufenacet and its thidadone degradate. 

SWCC Input Parameter Input Value and Unit 

(Flufenacet/Thiadone 

Degradate) 

Source 

Physical Chemical Properties

Molecular Weight (g/mol) 363/170 MRID 43441102 and 43850001 
Page 11 of 118 

Table 1. SWCC input parameter values used for surface water aquatic exposure estimation with 

flufenacet and its thidadone degradate. 

SWCC Input Parameter Input Value and Unit 

(Flufenacet/Thiadone 

Degradate) 

Source 

Vapor Pressure (torr) 2.40 x 10-11/1.5x10-2 MRID 43441102 and 43850001 

Solubility in Water (mg/L) 56/200,000 MRID 43441102 and 43850001 

Soil-Water Partition Coefficient (Koc) 

(mL/g) 

434.4/43.5 Average values 

MRID 43441137 and 43441140 

Environmental Fate Properties

Hydrolysis at pH7 (t1/2) Stable/Stable MRID 43441134 and 45796107 

Aerobic soil metabolism (t1/2), 

Reference Temperature, and 

Degradate Molar Formation Fraction 

48.2 days at 25°C/ 

2.77 days at 25°C 

Deg. Molar Formation 

Frac.:1.02

MRID 43441141, 43441135, 

43850058, & 48604493 

Upper 90TH percent confidence 

interval1

 

Aerobic aquatic metabolism (t1/2), 

Reference Temperature, and 

Degradate Molar Formation Fraction 

77.1 days at 25°C/160 days at 

25°C 

Deg. Molar Formation 

Frac.:1.02 

MRID 45796112, 44580203, & 

45796111 

Upper 90TH percent confidence 

interval1 

Anaerobic aquatic metabolism (t1/2) 

and Reference Temperature 

492 days at 25°C /303 days at 

25°C 

Deg. Molar Formation 

Frac.:1.02

MRID 43850060, 43850061, & 

45796110 

Upper 90th percent confidence 

interval1

 

Aqueous Photolysis (t1/2) and 

Reference latitude 

Stable at 45°N/Stable at 45°N MRID 43850056 and 46997401 

1

 The upper 90th percent confidence bount half-life calculated as follows: t1/2 input = ݐଵ/ଶ തതതതത + (t90, n-1 x σ) 

 n1/2 

where ݐଵ/ଶ തതതതത is the mean of the set of half lives from each study, t90, n-1 is the one-sided t value for the 90th percent 

confidence bound, σ is the standard deviation of the set of half-lives determined from each study, and n is the 

sample size of the set of half-lives determined from each study. 2

 A value of 1 is selected based on a one-to-one stoichiometric relationship in the formation pathway of thiadone 

from parent flufenacet. 
Page 12 of 118 

1 Crop scenarios presented highest exposure and most vulnerable scenario for all flufenacet uses confined to the Midwest, North C

Plains, and Oregon. 

2 Maximum single application rate specified on product labels. 3 Specified on product labels. 4 The most conservative application method evaluated based on crop uses specified on product labels. 5 EFED input parameter guidance for aerial and ground applications. 6 Spray drift fraction for aerial and ground applications from Table 2 of EPA, 2013, “Guidance on Modeling Offsite Deposition of P

Table 2. SWCC crop scenario and application methods input parameter values for flufenacet aquatic exp

Crop Use

SWCC Application Method and Crop Scenario Input Parameters 

SWCC Scenario and 

Weather Station1

Application 

Rate 

(kg a.i./ha)2

Number of 

Applications 

and 

Retreatment 

Interval2

Application 

Time 

Window3

Application 

Methods4

Ap

Ef

Corn (Sweet, Field, and Silage) 

IL Corn 14842.dvf (Peoria, IL) 

0.898 

1 app. 

15 days 

before crop 

emergence 

Ground 

Spray 

Soybeans MI Beans 

14826.dvf (Flint, MI) 

0.520 

Wheat and Triticale ND Wheat 

14914.dvf (Fargo, ND) 

0.386 

Grass Seed OR Grass Seed 

24232.dvf (Salem, OR) 

0.495 
Page 13 of 118 

Table 3. SWCC estimated upper bound concentrations in the 

surface water column for flufenacet and flufenacet thiadone total 

toxic residue at the highest application rate for proposed crop uses 

(flufenacet equivalent ppb). 

Crop Use 

(SWCC Scenario) Surface Water Column EECs (μg/L) 

Peak 21-day 60-day 

Corn 

(IL Corn) 26.5 25.4 23.7 

Soybeans 

(MI Beans) 9.0 8.5 8.3 

Wheat and Triticale 

(ND Wheat) 6.7 6.5 6.3 

Grass Seed 

(OR Grass Seed) 4.5 4.3 4.1 

*Bold text indicate maximum values. 

1

 One-in-ten year estimated value. 

Water Quality Monitoring Data

There are some water monitoring data available for flufenacet and its degradates in surface water, 

stream water, and ground water from the USGS National Water Quality Assessment (NAWQA) 

and EPA’s Storage and Retrieval Warehouse (STORET) monitoring datasets. In general, these 

monitoring data indicate that the SWCC and PRZM-GW modeling provide reasonably protective 

estimates of aquatic exposure. In addition, there are additional monitoring data in untreated 

drinking water, finished drinking water, as well ground water in the EPA Pesticide Data Program 

(PDP). With all of these data, it should be noted that there are no indications whether or not these 

data represent targeted sampling observations. However, there is also a targeted Prospective 

Ground Water Study submitted by the registrant for flufenacet and its degradates available as well 

(MRID No. 46997402). 

The NAWQA monitoring dataset encompasses 1,860 samples of parent flufenacet at various 

surface water and ground water monitoring sites for the period between 2001and 2012. Flufenacet 

degradates are not known to have been sampled. The nature of detections of flufenacet in the 

NAWQA data are summarized below: 

 Flufenacet was detected in stream water 14 times out of 797 total surface water samples at 

various sites in Iowa, Nebraska, Ohio, Maryland, and South Carolina. Concentrations of 

up to 0.31 ppb were detected in Dodge County, Iowa. 

 Flufenacet was detected in wells 3 times out of 895 total ground water samples at various 

sites in Iowa and Minnesota. Concentrations of up to 0.04 ppb in ground water were 

detected in Buena Vista County, Iowa. 

 Flufenacet was detected twice out of 222 total samples in stream sediment pore water, 

both instances in Nebraska, with concentrations of up to 0.74 ppb detected in Colfax 

County. 
Page 14 of 118 

 Flufenacet was detected at once out of 36 total samples at a distributed drinking water 

facility in Sandova County, NM at concentrations of up to 0.04 ppb. Details on the exact 

siting of concentrations within influent or finished water was not provided. 

An expanse of water monitoring information related to sampling of flufenacet’s oxalate 

degradate in Minnesota is available from the STORET database. The sampling occurred 

between the years 2010 – 2013. No detections were found out of 2,069 samples. 

There is a further expanse of monitoring data available from EPA’s PDP from drinking water 

facilities and ground water well for flufenacet. Flufenacet was only detected once in finished 

surface water out of 964 samples. However, the magnitude of detection was really large at 75 

ppb. This detection occurred in Indiana in 2007. Flufenacet was not sampled in ground water in 

the PDP. 

Furthermore, there is a targeted prospective ground water study conducted in six monitoring 

wells encompassing shallow wells (15 to 25 ft. below ground surface) and deep wells (25 to 30 

ft. below ground surface) for flufenacet, and its thiadone degradate (MRID No. 46997402). The 

monitoring study was conducted concurrent to a pre-emergent application of Flufenacet in a corn 

field possessing silt loam soil located in the town of Minden in Central Nebraska during June of 

1995. The monitoring data with each constituent is described below: 

 Flufenacet was only detected one time in a shallow well at 0.04 ppb within 30 days of the 

application. 

 The thiadone degradate was detected extensively but at low levels starting at 119 days 

after the application in both in shallow and deep wells. Concentrations ranged as high 

0.18 ppb at 501 days after the application. The thiadone degradate was not detected after 

1,155 days after the application. 

3.4 Terrestrial Exposure Analysis 

Terrestrial wildlife exposure estimates are typically calculated for birds and mammals. This 

assessment focuses on the dietary exposure route for birds and mammals (see Section 3.2). For 

exposure to terrestrial organisms, such as birds and small mammals, pesticide residues on food 

items are estimated, based on the assumption that organisms are exposed to a single pesticide 

residue in a given exposure scenario. 

a. Terrestrial Animal Dietary Exposure Estimation 

A primary concern with flufenacet is that birds and mammals may be exposed shortly after 

application through oral or dietary exposure to seeds or insects when foraging in the treated fields 

for nesting material or food. Therefore estimation of pesticide concentrations in wildlife food 

items focuses on quantifying possible dietary ingestion of residues on vegetative matter and 

insects. The EFED terrestrial exposure model T-REX (T-REX, Version 1.5, released 03/2012) is 

used to estimate exposures and risks to avian and mammalian species. Input values for avian and 
Page 15 of 118 

mammalian toxicity as well as chemical application and foliar dissipation half-life data are 

required to run the model. The model provides estimates of exposure concentrations and risk 

quotients (RQs). Specifically, the model provides estimates of concentrations (upper-bound and 

mean) of chemical residues on the surface of different types of foliage and insects that may be 

dietary sources of exposure to avian, mammalian, reptilian, or terrestrial-phase amphibian 

receptors. The surface residue concentration (ppm) is estimated by multiplying the application 

rate (pounds active ingredient per acre) by a value specific to each food item. These values (termed 

the Hoerger-Kenaga estimates) along with a more detailed discussion of the methodology 

implemented by T-REX, are presented in Appendix E (T-REX Model). 

Input values used for estimating avian and mammalian exposure risks to flufenacet are summarized 

in Table 4

Table 4. Input parameters used in T-REX v 1.2.5 to determine terrestrial 

EECs for the maximum flufenacet spray application scenarios.

Input Parameters Value Source 

Single Application 

Rate 

(lb a.i./A) 

Corn (sweet and field), soybeans 0.8019

Product 

labels    

Soybean 0.4644

Grass Seed 0.442

Wheat, Triticale 0.3448

Foliar Half-life 35 days Default 

value1

Number of 

Applications 

(Interval between 

Applications, days) 

All flufenacet uses 1 Product 

labels

Avian Oral LD50 461 mg/kg-bw (canary) MRID 

49244202 

Avian Reproduction 

NOEAC 88.0 ppm (mallard) MRID 43441120 

Mammal LD50 589 mg/kg-bw (rat) MRID 

43441104 

Mammal NOAEC 1.3 mg/kg-diet (rat) MRID 

3850033 

1 The foliar half-life did not influence the prediction of the terrestrial EECs for flufenacet 

because only one application of flufenacet is allowed per season, and thus the peak 

concentration occurs immediately after this single application before any dissipation occurs. 

By comparing estimated exposure concentrations to acute and chronic toxicity reference values, 

RQs are calculated. The EECs on food items may be compared directly with dietary toxicity data 

or converted to an oral dose, as is done for small mammals. For mammals, the residue 
Page 16 of 118 

concentration is converted to daily oral dose based on the fraction of body weight consumed daily 

as estimated through mammalian allometric relationships. The screening-level risk assessment for 

flufenacet uses upper-bound predicted residues as the measure of exposure. Consideration is given 

to different types of feeding strategies for mammals, including herbivores, insectivores and 

granivores. Dose-based exposures are estimated for three weight classes of birds (20 g, 100 g, and 

1000 g) and three weight classes of mammals (15 g, 35 g, and 1000 g). Summaries of the predicted 

upper-bound residues of flufenacet that may be expected to occur on selected avian or mammalian 

food items immediately following application for the maximum use scenario are presented in 

Tables 5, 6, and 7.

For the maximum flufenacet application scenario, concentrations for different forage types ranged 

from 0.8 to 219.2 ppm for upper-bound residues and 0.36 to 77.63 ppm for mean residues. 

Flufenacet concentrations were highest on the surfaces of short grass and lowest on the seeds. 
Page 17 of 118 

Table 5. Avian TREX dose-based EECs (mg/kg).

Use and

application

rate

(lbs a.i./A)

20 g "Small" Bird 100 gram "Medium" Bird 1000 gram "Large" 

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Corn

(Sweet

and Field)

(0.8019)

219.2 100.5 123.3 13.7 85.8 3.0 125.0 57.3 70.3 7.8 49.0 1.7 56.0 25.6 31.5 3.5 

Soybean

(0.4644) 126.9 58.2 71.4 7.9 49.7 1.8 72.4 33.2 40.7 4.5 28.4 1.0 32.4 14.9 18.2 2.0 

Grass Seed

(0.442) 120.8 55.4 68.0 7.6 47.3 1.7 68.9 31.6 38.8 4.3 27.0 1.0 30.8 14.1 17.4 1.9 

Wheat,

Triticale

(0.3448)

94.2 43.2 53.0 5.9 36.9 1.3 53.7 24.6 30.2 3.4 21.0 0.7 24.1 11.0 13.5 1.5 
Page 18 of 118 

Table 6. Mammalian TREX dose based EECs (mg/kg).

Use and

application rate

(lbs a.i./A)

15 gram "Small" Mammal 35 gram "Medium" Mammal 1000 gram "Large" 

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Corn (Sweet and

Field)

(0.8019)

183.5 84.1 103.2 11.5 71.9 2.5 126.8 58.1 71.3 7.9 49.7 1.8 29.4 13.5 16.5 1.8 

Soybean

(0.4644) 106.3 48.7 59.8 6.6 41.6 1.5 73.4 33.7 41.3 4.6 28.8 1.0 17.0 7.8 9.6 1.1 

Grass Seed

(0.442) 101.1 46.4 56.9 6.3 39.6 1.4 69.9 32.0 39.3 4.4 27.4 1.0 16.2 7.4 9.1 1.0 

Wheat, Triticale

(0.3448) 78.9 36.2 44.4 4.9 30.9 1.1 54.5 25.0 30.7 3.4 21.4 0.8 12.6 5.8 7.1 0.8 
Page 19 of 118 

Table 7. TREX dietary-based EECs (mg/kg). 

Use and application 

rate (lbs a.i./A) 

Short Grass 

Tall Grass 

Broadleaf Plants 

Fruits/pods 

Arthropods 

Corn (Sweet and

Field)  

(0.8019)

192 88 108 12 75

Soybean

(0.4644) 111 51 63 7 44

Grass Seed  

(0.442) 106 49 60 7 42

Wheat & Triticale

(0.3448) 83 38 47 5 32

b. Terrestrial Plant Exposure Estimation 

There are three routes of exposure to terrestrial plants for flufenacet. Off-site transport via spray 

drift and runoff are two of these exposure routes. The third is the application of irrigation water 

to non-target crops and plants potentially contaminated with flufenacet residues. 

The TerrPlant model (v. 1.2.2; December 26, 2006) evaluates terrestrial plant exposure 

contributions from runoff and spray drift. It is used to derive EECs relevant to terrestrial and 

wetland plants. The model employs the assumption that default fractions of the intended 

application are transported to an adjacent field through runoff and spray drift. Measures of 

exposure to terrestrial plants are expressed as a fraction of the mass of the flufenacet applied to the 

treated field. TerrPlant EECs are shown in Table 8 below. 
Page 20 of 118 

Table 8. TerrPlant EECs (lbs. a.i./A) for flufenacet exposure to terrestrial and wetland 

plants resulting from runoff and spray drift.

Use (application rate ‐ lbs

a.i./A) Description of Area 

EEC 

(lbs 

a.i/A) 

Corn (Sweet and Field) (0.8019)

Runoff to dry areas 0.008

Runoff to semi-aquatic areas 0.080

Spray drift 0.008

Total for dry areas 0.016

Total for semi-aquatic areas 0.088

Soybean  

(0.4644)

Runoff to dry areas 0.005

Runoff to semi-aquatic areas 0.046

Spray drift 0.005

Total for dry areas 0.009

Total for semi-aquatic areas 0.051

Grass Seed

(0.442)

Runoff to dry areas 0.004

Runoff to semi-aquatic areas 0.044

Spray drift 0.004

Total for dry areas 0.009

Total for semi-aquatic areas 0.049

Wheat & Triticale (0.3448)

Runoff to dry areas 0.007

Runoff to semi-aquatic areas 0.069

Spray drift 0.003

Total for dry areas 0.010

Total for semi-aquatic areas 0.072

Potential exposure via flufenacet residues in irrigation water applied to non-target plants and crops 

can be estimated from EECs in surface water and ground water. For flufenacet, surface water 

EECs (including flufenacet and flufenacet thiadone) are higher than ground water (refer to 

Appendix D showing ground water estimation modeling results). Therefore, peak EECs for 

flufenacet only in the surface water column as presented in Table 17 serves as the preliminary 

basis for deriving equivalent EECs to plants impacted via this exposure occurring associated with 

irrigation practices. Further analysis related to this exposure pathway is provided in the Risk 

Description Section (Section 5.2.2). 
Page 21 of 118 

c. Terrestrial Invertebrate Exposure Estimation 

Exposure to bees is expected with applications through boom spray. Drift from the boom sprayers 

or residues may come into contact with pollinators either through direct contact or contact with 

residues. Possible exposures from either acute contact or oral exposure to the proposed 

applications rates were calculated using Bee-Rex modeling. To calculate contact exposure, the 

application rate was multiplied by 2.7 μg a.i./bee. Oral exposure was calculated by multiplying 

the application rate by ((110 μg a.i./g)*0.292g/day)). For details see the Guidance for Assessing 

Pesticide Risks to Bees (USEPA, 2014). Estimated dose exposure concentrations for honeybee 

contact and oral exposure is presented in Table 9 resulting from each flufenacet use. 

Table 9. Flufenacet contact and oral estimated exposure dose 

concentrations to honeybees.

Use (Application Rate ‐ 

lbs a.i./A)

Contact Exposure

(mg/kg)

Oral Exposure

(mg/kg)

Corn (Sweet and Field)

(0.8019) 2.17 25.76

Soybean  

(0.4644) 1.24 14.78

Grass Seed  

(0.442) 1.19 14.20

Wheat & Triticale  

(0.3448) 0.93 11.06

4. Ecological Effects Characterization 

The ecological effects characterization for flufenacet is based upon registrant-submitted toxicity 

data for the TGAI (parent flufenacet) and for specified formulations. 

4.1 Aquatic Effects Summary 

Flufenacet exposure effects on aquatic organisms were determined by assessing freshwater and 

estuarine/marine taxa. Five new studies (a chronic toxicity test with the sheepshead minnow 

(MRID 49244201), an acute and a chronic toxicity test with the mysid shrimp (MRIDs 49119001 

and 49119002), and degradate toxicity tests with the fresh water vascular plant Lemna gibba 

(MRID 48897612) and the non-vascular plant Selenastrum capricornutum (MRID 45796115) 

have been submitted and reviewed since the time of the last assessment. These studies are 

summarized below. The most sensitive endpoints for the remaining taxa that will be used in this 

risk assessment are presented in Table 10. Refer to the 2010 assessment for more comprehensive 

descriptions of the studies. 

Chronic Toxicity to Sheepshead minnow (Cyprinodon variegatus) 
Page 22 of 118 

The 35-day chronic toxicity of flufenacet to the early life-stage of sheepshead minnow 

(Cyprinodon variegatus) was studied under flow-through conditions (MRID 49244201). Meanmeasured treatment concentrations were <4.0 (<LOQ, control), 49, 95, 174, 339 and 677 μg ai/L. 

No treatment-related effect on survival was indicated at any level: survival (Day 6) ranged from 

87.9 to 90.7% for all levels and fry survival (Day 35) ranged from 95.0 to 98.8%. No treatmentrelated effect on time to hatch was observed. On Days 5 and 6, percent hatch for all levels ranged 

from 29.3 to 39.3% and 84.3 to 89.3%, respectively, no statistically-significant differences from 

the control were found. At the 677 μg ai/L level, fish were observed to be swimming at the bottom 

of the test vessel, except when being fed, beginning on Day 32. Growth (at study termination) was 

the most sensitive endpoint. For both growth parameters, differences were statistically-significant 

compared to the control (p=0.05) at the ≥95 μg ai/L levels. Reductions in length were observed to 

be 4%, 4%, and 7% while reductions in weight were observed to by 6%, 9%, and 19% in the 174, 

339 and 677 μg ai/L treatment levels respectively. The overall NOAEC and LOAEC were 49 and 

95 μg ai/L, respectively, based upon a treatment-related reduction in standard length and dry 

weight on Day 35 at the ≥95 μg ai/L levels. This study is scientifically sound and meets the 

guideline requirements for an early life stage toxicity study with fish. It is therefore classified as 

acceptable.

Acute Toxicity to Mysid Shrimp (Mysidopsis bahia) 

In a 96 hour acute toxicity test, the saltwater mysid shrimp (Mysidopsis bahia) were exposed to 

flufenacet in measured concentrations of <LOQ (negative control), 0.29, 0.59, 1.2, 2.3, 4.7, 9.5 

mg a.i./L(MRID 49119001). After 96 hours, no mortality was observed in the control or ≤2.3 mg 

ai/L treatment groups. At 4.7 and 9.5 mg ai/L, mortality was 10 % and 50 % respectively after 48 

hours, 20% and 70% respectively after 72 hours and 30% and 95%, respectively after 96 hours. 

All mysids in the ≤2.3 mg ai/L treatment groups appeared normal. In the 4.7 mg ai/L group, 

lethargy was observed during the 96-hour interval. In the 9.5 mg ai/L group, signs of toxicity 

(lethargy or surfacing) were observed during the 48-, 72- and 96-hour intervals. The LC50 was 

5.59 (4.72-6.66) mg ai/L classifying flufenacet as moderately toxic to the mysid shrimp. This 

study was scientifically sound and met the guideline requirements for an acute toxicity test with 

an estuarine/marine invertebrate and is classified as acceptable. 

Chronic Toxicity to Mysid Shrimp (Mysidopsis bahia) 

A 31 day chronic toxicity test exposed mysid shrimp neonates (< 24 hours old) were exposed to 

mean measured treatment concentrations of <LOQ (negative control), 33, 68, 126, 221, 469 ug 

a.i./L (MRID 49119002). There were not any statistical differences in any of the endpoints (F0

survival (pre-pairing and entire study), reproduction (mean number of young per female), time to 

first brood, and sex-specific length and dry weight) relative to the negative control. Reproduction 

(number of offspring per female) did however exhibit a 34.4 % reduction relative to the negative 

control. The NOAEC and LOAEC values were visually determined to be 221 and 469 μg ai/L, 

respectively due to the magnitude of this reduction. This study was scientifically sound and met 

the guideline requirements for a chronic toxicity test with an estuarine/marine invertebrate and is 

classified as acceptable. 
Page 23 of 118 

Table 10. Summary of Acute and Chronic Toxicity Data for Aquatic Taxa 

Exposed to Flufenacet.

Exposure 

Scenario Species Scientific Name Exposure Duration 

Toxicity 

Reference 

Value 

(ppm) 

Endpoints 

Affected 

Reference 

(Classification) 

Freshwater Fish 

Acute Bluegill 

Sunfish 

Lepomis 

macrochirus 96 hours LC50 = 2.26 Mortality 

MRID 

43595501 

Moderately 

Toxic 

(Acceptable) 

Chronic Rainbow 

Trout 

Oncorhynchus 

mykiss 289 days 

NOAEC/ 

LOAEC = 

0.075/0.138 

Growth 

MRID 

45796114 

(Supplemental) 

Freshwater Invertebrate 

Acute Isopod Hyalella azteca 96 hours LC50 = 2.80 Mortality 

MRID 

43595503 

Moderately 

Toxic 

(Acceptable) 

Chronic Waterflea 

Daphnia 

21 days 

NOAEC/ 

LOAEC = 

6.3/12.8 

Reproduction MRID 

43441126 

magna (Number of 

neonates/repro- (Acceptable) 

   ductive day & 

time to first 

brood.) 

  

Estuarine Fish 

Acute Sheepshead 

Minnow 

Cyprinodon 

variegatus 96 hours LC50=3.38 Mortality 

MRID 

43441122 

Moderately 

Toxic 

(Acceptable) 
Page 24 of 118 

Table 10. Summary of Acute and Chronic Toxicity Data for Aquatic Taxa 

Exposed to Flufenacet.

Exposure 

Scenario Species Scientific Name Exposure Duration 

Toxicity 

Reference 

Value 

(ppm) 

Endpoints 

Affected 

Reference 

(Classification) 

Chronic Sheepshead 

Minnow 

Cyprinodon 

variegatus 35 days 

NOAEC/ 

LOAEC = 

0.049 / 

0.095 

Growth 

(standard 

length and dry 

weight) 

MRID 

49244201 

(Acceptable) 

Estuarine Invertebrates 

Acute Mysid 

Shrimp Mysidopsis bahia 96 hours LC50=2.72 Mortality 

MRID 

43441121 

Moderately 

Toxic 

(Supplemental) 

Acute Mysid 

Shrimp Mysidopsis bahia 96 hours LC50=5.59 

(slope 7.3) Mortality 

MRID 

49119001 

Moderately 

Toxic 

(Acceptable) 

Chronic Mysid 

Shrimp Mysidopsis bahia 28 days 

NOAEC/ 

LOAEC = 

0.012/0.022 

Growth, 

Larvae 

Survival, & 

Young/Female/ 

MRID 

43595502 

Reproductive 

Day (Supplemental) 

Chronic Mysid 

Shrimp Mysidopsis bahia 31 days 

NOAEC/ 

LOAEC = 

0.221/0.469 

Reproduction 

(number of 

young 

produced per 

surviving 

female 

MRID 

49119002 

 

(Acceptable) 

Aquatic Plants 

Non-Vascular Green 

Algae 

Pseudokirchneriella 

subcapitata 120 hours 

EC50 = 

0.0029 

Cell Density 

MRID 

43834402 

NOAEC or 

EC05 = 

0.00252 

(Acceptable) 
Page 25 of 118 

Table 10. Summary of Acute and Chronic Toxicity Data for Aquatic Taxa 

Exposed to Flufenacet.

Exposure 

Scenario Species Scientific Name Exposure Duration 

Toxicity 

Reference 

Value 

(ppm) 

Endpoints 

Affected 

Reference 

(Classification) 

Vascular Duckweed Lemna gibba 14 days 

EC50 = 

0.00245 

Plant/Frond 

Density 

MRID 

43441132 

NOAEC or 

EC05 = 

0.00044 

(Acceptable) 

4.2 Terrestrial Effects Summary 

There have been seven new studies submitted examining the toxicity of flufenacet and coformulations of flufenacet and other active ingredients on both vegetative vigor (Guideline number 

850.4250) and seedling emergence (Guideline number 850.4225) of terrestrial plant species. 

These studies examine Flufenacet SC500 (MRIDs 48897605 and 48897609), Flufenacet & 

Isoxaflutole WG 58 (MRIDs 48897606 and 48897610), Flufenacet and Isoxaflutole SC 480 

(MRIDs 48897607 and 48897611), and Axiom 68DF (MRID 48897688). These studies are still 

being reviewed. The results of these studies may indicate that formulated products may be more 

or less toxic to terrestrial plant species than the terrestrial plants studies currently used in this 

preliminary risk assessment and may result in buffers of different widths necessary to mitigate 

risk. Results of these studies will be incorporated into the final risk assessment when the results 

become available. 

There have also been two studies submitted since the last assessment for acute avian toxicity; acute 

toxicity to the passerine species Serinus canaria (MRID 49244202) and acute toxicity to the 

Mallard duck (MRID 44246801). The most sensitive endpoints for the remaining taxa that will be 

used in this risk assessment are presented in Table 11. Refer to the 2010 problem formulation for 

more comprehensive descriptions of the studies. 

Toxicity to the Passerine Serinus canaria 

An acute oral toxicity study of flufenacet to adult canaries (Serinus canaria) was submitted since 

the last assessment (MRID 49244202). Flufenacet technical was administered neat to the birds 

via corn oil-coated gelatin capsules at nominal doses of 0, 135, 236, 413, 723 and 1265 mg ai/kg 

bw (adjusted for purity) and birds were assessed for 14 days. Cumulative mortality was 10, 0, 10, 

40, 90 and 100% in the control, 135, 236, 413, 723 and 1265 mg ai/kg bw dose levels, respectively; 

all treatment-related deaths occurred by Day 1, with no gender-related differences. Ataxia and 

diminished reaction to stimuli (hypo-reactivity) were observed in birds from the ≥236 mg ai/kg 

dose levels. Effects were noted within 1 hour of dosing, and surviving birds from all levels 

recovered by Day 2. The 14-day acute oral LD50 (with 95% C.I.) was 461 (291 to 598) mg ai/kg 

bw classifying flufenacet as moderately toxic to adult canary on an acute oral basis. This study is 

acceptable and meets guideline requirements for acute oral toxicity with a passerine species. 
Page 26 of 118 

Toxicity to the Mallard duck Anas platyrhynchos 

The acute oral toxicity of FOE5043 Technical (Flufenacet) to the Mallard Duck was assessed in a 

14 day study (MRID 44246801). Approximately 20 week old mallard ducks (6 per treatment level) 

were exposed to flufenacet at concentrations of 0, 60, 100, 250, 500, 1000, and 2000 mg a.i./kg 

bw. Mortality occurred in the two highest treatment levels (2 in the 1000 mg a.i./kg bw treatment 

and 1 in the 2000 mg a.i./kg bw treatment). The LD50 was determined to be > 2000 mg a.i./kg bw. 

The birds did not exhibit signs of toxicity or significant differences in body weight gain and there 

were not any sublethal effects that were noted. This toxicity study is classified as supplemental

as it is scientifically sound but has deficiencies that limit its usefulness. The study only included 

6 replicate birds, not the recommended 10. 

Table 11. Summary of Toxicity for Terrestrial Taxa Exposed to Flufenacet

Exposure 

Scenario Species Scientific Name 

Exposure 

Duration 

Toxicity 

Reference 

Value 

Effects 

Reference 

(Classification) 

Mammals 

Acute Laboratory 

Rat 

Rattus 

norvegicus Acute Oral 

LD50 = 

589 

mg/kg 

Mortality 

MRID 

43441104 

(Acceptable) 

Chronic Laboratory 

Rat 

Rattus 

norvegicus 

2-generation 

reproduction 

NOAEL = 

1.3 

mg/kg/day 

Increase in 

pup death in 

early 

lactation 

(including 

cannibalism). 

MRID 3850033 

(Acceptable) 

Invertebrates 

Acute 

Contact Honey bee Apis mellifera 48 hours > 25 μg 

ai/bee Mortality 

44112201 

(Acceptable) 

Birds 

Acute 

(Dosebased) 

Bobwhite 

Quail 

Colinus 

virginianus 15 days 

LD50 = 

1608 mg 

a.i./kg 

Mortality 

MRID 

43441113 

(Acceptable) 

Acute 

(Dosebased) 

Mallard 

Duck 

Anas 

platyrhynchos 14 days 

LD50 > 

2000 mg 

a.i./kg 

Mortality 

MRID 

44246801 

(Supplemental) 

Acute 

(Dosebased) 

Canary Serinus 

canaria 14 days 

LD50 = 

461 mg 

a.i./kg 

Mortality 

MRID 

49244202 

(Acceptable) 

Moderately 

toxic 
Page 27 of 118 

Table 11. Summary of Toxicity for Terrestrial Taxa Exposed to Flufenacet

Exposure 

Scenario Species Scientific Name 

Exposure 

Duration 

Toxicity 

Reference 

Value 

Effects 

Reference 

(Classification) 

Acute 

(Dietarybased) 

Bobwhite 

Quail 

Colinus 

virginianus 11 days 

LD50 = 

5317 mg 

a.i./kg 

Mortality 

MRID 

43441114 

(Acceptable) 

Acute 

(Dietarybased) 

Mallard 

Duck 

Anas 

platyrhynchos 11 days 

LD50 = 

4970 mg 

a.i./kg 

(slope 

6.44) 

Mortality 

MRID 

43441115 

(Acceptable) 

Chronic Mallard 

Duck 

Anas 

platyrhynchos 

21 weeks 

NOAEL = 

88 ppm 

Increase in 

number of 

eggs cracked 

and decrease 

in normal 

hatchlings 

and survivors 

MRID 

43441120 

(Acceptable) 

Reproduction 

Plants 

Seedling 

Emergence 

Sorghum 

Sorghum 

vulgare 21 days 

EC25 = 

0.006 lbs 

a.i./A 

Shoot Dry 

Weight 

MRID 

43465002 

(Monocot) 

NOAEL = 

0.004 lbs 

a.i./A (Acceptable) 

Tomato 

Lycopersicon 

esculentum 21 days 

EC25 = 

0.022 lbs 

a.i./A Shoot Dry 

Weight 

MRID 

43465002 

(Dicot) 

NOAEL = 

0.007 lbs 

a.i./A 

(Acceptable) 

Vegetative 

Vigor 

Sorghum 

Sorghum 

vulgare 21 days 

EC25 = 

0.017 lbs 

a.i./A 

Shoot Height 

MRID 

43465002 

(Monocot) 

NOAEL = 

0.008 lbs 

a.i./A 

(Acceptable) 

Cucumber 

Cucumis 

sativus 21 days 

EC25 = 

0.032 lbs 

a.i./A Shoot Dry 

Weight 

MRID 

43465002 

(Dicot) 

NOAEL = 

0.016 lbs 

a.i./A 

(Acceptable) 
Page 28 of 118 

4.3 Degradate toxicity 

As described in Section 3.1, flufenacet is subject to degradation to various products in the 

environment via multiple pathways via its cleavage to thiadone, and its anilide alcohol, 

methylsulfoxide, oxylate, and sulfonic acid by-products potentially impacting aquatic organisms. 

Extensive ecological toxicity studies exist with the flufenacet thiadone degradate for aquatic 

organisms, and results for the studies are shown in Table 12 below. The thiadone degradate is as 

toxic or slightly less toxic to aquatic animals than parent flufenacet (LC50 range = 8.4 to 31.7 ppm 

per MRID 45796101, 45796102, 45796103, 45796104, and 45796106). In addition, data suggest 

equivalent toxicity of thiadone relative to parent flufenacet to aquatic non-vascular and vascular 

plants. One study since the last assessment was submitted for toxicity of thiadone on aquatic 

vascular plants, summarized below: 

Toxicity to Duckweed (Lemna gibba) 

A 7-day acute toxicity study exposed the freshwater aquatic vascular plants (duckweed, Lemna 

gibba G3) to Flufenacet-thiadone at mean measured concentrations of <0.100 (<LOQ, negative 

control), 1.54, 2.60, 5.13, 10.2, 20.8, 41.3, and 84.1 mg ai/L (MRID 48897612). The mean frond 

number had inhibitions relative to the negative control of 15, 12, 28, 37, 65, 84, and 91% for 

mean measured concentrations of 1.54, 2.60, 5.13, 10.2, 20.8, 41.3, and 84.1 mg ai/L, 

respectively. The frond number growth rate had inhibitions relative to the negative control of 

6.87, 5.77, 14.2, 19.7, 43.8, 76.6, and 100% for mean measured concentrations of 1.54, 2.60, 

5.13, 10.2, 20.8, 41.3, and 84.1 mg ai/L, respectively. The frond number yield had inhibitions 

relative to the negative control of 17, 14, 31, 41, 71, 92, and 100% for mean measured 

concentrations of 1.54, 2.60, 5.13, 10.2, 20.8, 41.3, and 84.1 mg ai/L, respectively. The mean 

frond area had inhibitions relative to the negative control of 13, 11, 30, 45, 73, 88, and 91% for 

mean measured concentrations of 1.54, 2.60, 5.13, 10.2, 20.8, 41.3, and 84.1 mg ai/L, 

respectively. The frond area growth rate had inhibitions relative to the negative control of 1.90, 

5.81, 11.1, 20.0, 51.4, 88.2, and 98.3% for mean measured concentrations of 1.54, 2.60, 5.13, 

10.2, 20.8, 41.3, and 84.1 mg ai/L, respectively. The NOAEC values based on frond number 

yield, frond number growth rate, and frond area were <1.54 mg ai/L, in terms of mean measured 

concentrations. The IC05 for frond area growth rate was 1.101 mg/L and was slightly lower than 

the range of concentrations tested so should be interpreted with some caution. IC50 values based 

frond area was 10.34 mg ai/L. This study is scientifically sound and meets the guideline 

requirements for a toxicity test using a freshwater vascular plant. It was therefore classified as 

acceptable. 
Page 29 of 118 

Table 12. Summary of endpoints in aquatic toxicity studies for the flufenacet thiadone degradate. 

Test Group Species Scientific 

Name 

Exposure 

Duration 

Toxicity 

Reference 

Value 

(ppm) 

Endpoints 

Affected 

Reference 

(Classification) 

Vascular with 

flufenacetthiadone 

Duckweed Lemna gibba 14 days 

EC50 = 

10.34 

Frond area 

MRID 

48897612 

NOAEC 

or EC05 = 

1.101 

(Acceptable) 

Non-Vascular 

with Thiadone 

Green 

Algae 

Seleanstrum 

capricornutum 120 hours 

EC50 = 

6.4 

Cell 

Density 

MRID 

45796115 

NOAEC 

or EC05 = 

0.94 

(Acceptable) 

Freshwater fish Bluegill 

Sunfish 

Lepomis 

macrochirus 96 hrs LC50 = 

18.6 Mortality 

MRID 

45796101 

Slightly toxic 

(Supplemental) 

Freshwater fish Rainbow 

Trout 

Oncorhynchus 

mykiss 96 hrs LC50 = 8.4 Mortality 

MRID 

45796102 

Moderately 

toxic 

(Supplemental) 

Freshwater 

Invertebrate Daphnid Daphnia 

Magna 96 hrs LC50 = 

31.7 Mortality 

MRID 

45796103 

Slightly toxic 

(Acceptable) 

Estuarine/Marine 

Fish 

Sheepshead 

Minnow 

Cyprinodon 

variegatus 96 hrs LC50

=15.3 

Mortality 

and 

sublethal 

effects 

MRID 

45796104 

Slightly toxic 

(Supplemental) 

Estuarine/Marine 

Invertebrate 

Saltwater 

Mysid 

Mysidopsis 

bahia 96 hrs LC50 > 

15.1 Mortality 

MRID 

45796106 

Slightly toxic 

(Acceptable) 

For the additional degradates in the aquatic environment, the ECOSAR (v.1.11) module of 

EPISUITE (v.4.1) was employed to estimate the toxicity of these degradates as compared to the 

registrant submitted studies available for parent flufenacet and the thiadone degradate. ECOSAR 

uses structure activity relationships (SAR) to predict the toxicity of compounds that share similar 
Page 30 of 118 

structural moieties. The toxicity of each degradate is presented in Table 13 to enable comparison 

to laboratory submitted studies. ECOSAR indicates that only thiadone is predicted to have similar 

toxicity to the parent flufenacet compound. ECOSAR modelling suggested that the degradates 

were significantly less toxic than the parent compound. Because of this only registrant submitted 

toxicity studies for both the parent flufenacet compound and flufenacet’s thiadone degradate were 

used to compare to estimated environmental concentrations. Registrant submitted studies on both 

flufenacet and thiadone suggest however that flufenacet is more toxic than the thiadone degradate, 

particularly for aquatic plants. Regardless, the stressor of concern for ecological risk in aquatic 

environments will consider both residues of parent flufenacet and its thiadone degradate, 

since these compounds possess most toxicity by a wide margin as opposed to its anilide 

degradates. Furthermore, thiadone is included in this assessment since it is observed to reach 

very high levels, up to 84.3 percent of applied flufenacet. 

Table 13. ECOSAR predicted toxicity (mg a.i/L) of flufenacet degradates.

Stressor 

(Endpoint 

Source) 

 Endpoint (in mg a.i/L) 

ECOSAR 

CLASS 

Vascular 

Plant 

(EC50 / 

NOAEC) 

Nonvascular 

Plant 

(EC50 / 

NOAEC) 

Freshwater 

Fish LC50 / 

NOAEC 

Freshwater 

Invertebrate 

EC50 / 

NOAEC 

(different 

species) 

Estuarine/

Marine 

Fish LC50

Estuarine 

/Marine 

Invertebr

ate EC50

Flufenacet 

(registrant 

submitted 

studies) 

NA 0.00245 / 

0.00044 

0.0029 / 

0.00252 2.26 / 0.075 2.8 / 6.3 3.38 2.72 

Flufenacet 

(ECOSAR 

estimates) 

Amides 0.614 / 

0.956 

0.614 / 

0.956 

15.059 / 

0.053 9.5 / 1.18 13.464 1.2 

Thiadone 

(registrant 

submitted 

studies) 

NA 1.34/1.01 6.4/0.94 8.4 31.7 15.3 >15.1 

Thiadone 

(ECOSAR 

estimates) 

Hydrazines

/Thiocarba

mates 

0.39 / 0.14 0.39 / 0.14 1.3 / 0.05 4.4 / 0.24 3.9 2.7 

Methylsulf

ide 

(ECOSAR 

Estimate)* 

Amides 55 / 21 55 / 21 2807 / 1.3 8441 / 112 2425 

77 

Oxalate 

(ECOSAR 

Estimate) 

Neutral 

Organics 531/ 108 531/ 108 2219 / 190 1127 / 81 144 573 
Page 31 of 118 

Table 13. ECOSAR predicted toxicity (mg a.i/L) of flufenacet degradates.

Stressor 

(Endpoint 

Source) 

 Endpoint (in mg a.i/L) 

ECOSAR 

CLASS 

Vascular 

Plant 

(EC50 / 

NOAEC) 

Nonvascular 

Plant 

(EC50 / 

NOAEC) 

Freshwater 

Fish LC50 / 

NOAEC 

Freshwater 

Invertebrate 

EC50 / 

NOAEC 

(different 

species) 

Estuarine/

Marine 

Fish LC50

Estuarine 

/Marine 

Invertebr

ate EC50

Sulfonic 

Acid 

(ECOSAR 

Estimate)* 

Amidesacid 97.6 / 62 97.6 / 62 3793 / 3.7 6406 / 195 3319 157 

Flufenacet 

Alcohol 

(ECOSAR 

Estimate) 

Amides 4.2/ 3.2 4.2/ 3.2 150 / 0.189 211 / 8.4 132.5 7.1 

 

In terrestrial environments, parent flufenacet is moderately persistent in the environment with 

aerobic soil metabolism half-lives of 34 to 64 days. Furthermore, since thiadone itself has a short 

half-life in terrestrial environments, its availability to terrestrial animals on an acute or long-term 

basis may be limited, decreasing the potential for acute and chronic risk to these species. 

Therefore, given the resulting limited exposure anticipated to terrestrial plants and animals, 

modeling exposure to these organisms will use parent flufenacet alone. 

4.4 ECOTOX Open Literature 

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. The evaluation of both sources of data can also provide 

insight into the direct and indirect effects of pesticides on biotic communities from loss of species 

that are sensitive to the chemicals and from changes in structure and functional characteristics of 

the affected communities. Findings from this survey did not provide any information that would 

significantly affect this risk assessment. 

4.5 Review of Incident Data 

Incident reports submitted to EPA since approximately 1994 have been tracked by assignment of 

“incident numbers” in an Incident Data System (IDS), microfiched, and then entered into a second 

database, the Ecological Incident Information System (EIIS; USEPA 2007b). An effort has also 

been made to enter information to EIIS on incident reports received prior to establishment of 

current databases. Incident reports are not received in a consistent format (e.g., states and various 

laboratories usually have their own formats), may involve multiple incidents involving multiple 

chemicals in one report, and may report only part of a given incident investigation (e.g., residues). 

While some progress has been made in recent years in getting incident reports submitted and 
Page 32 of 118 

entered, there has never been the level of resources assigned to incidents that there has been 

assigned to the tracking and review of laboratory toxicity studies, for example. 

A preliminary review of the EIIS and the Avian Monitoring Information System (AIMS), which 

is maintained by the American Bird Conservancy, indicates there are no incidents for wildlife. 

However, there are 64 plant incident reports involving terrestrial exposure to flufenacet that have 

been reported and none that involve aquatic species. Flufenacet was applied to agricultural crops 

(corn, soybeans, and winter wheat) and in most cases the treated crop itself was affected. Only 

two incidents showed that flufenacet damaged crops via drift to another crop. The magnitude of 

damage ranged from a small area (1 acre) to the entire treated crop, with most being at least greater 

than 50% of the treated crop or more than 100 acres. 

In addition to the incidents recorded in EIIS, additional incidents have been reported to the Agency 

in aggregated incident reports. Pesticide registrants report certain types of incidents to the Agency 

as aggregate counts of incidents occurring per product per quarter. Ecological incidents reported 

in aggregate reports include those categorized as “minor fish and wildlife” (W-B), “minor plant” 

(P-B), and “other nontarget” (ONT) incidents. “Other nontarget” incidents include reports of 

adverse effects to insects and other terrestrial invertebrates. For flufenacet, registrants have 

reported 994 minor plant incidents but no minor fish and wildlife incidents or other nontarget 

incidents. 

In the risk assessment, the incidents will be further evaluated to determine if the reported incidents 

represent current patterns of use for flufenacet. Examples of additional considerations are 

mitigation (e.g., reduced application rates), product cancellations, and changes in use patterns that 

have occurred since the date of the reported incidents. 

An absence of reported incidents should not be construed as the absence of incidents. Incident 

reports for non-target organisms typically provide information only on mortality events and plant 

damage incidents. Except for phytotoxic effects in terrestrial plants, sublethal effects, such as 

reduced growth or impaired reproduction, are rarely reported. EPA’s changes in the registrant 

reporting requirements for incidents in 1998 may account for a reduced number of reported 

incidents. Registrants are now only required to submit detailed information on ‘major’ fish, 

wildlife, and plant incidents. Minor fish, wildlife, and plant incidents, as well as all other nontarget 

incidents, are generally reported aggregately and are not included in the EIIS. In addition, there 

have been changes in state monitoring efforts due to a lack of resources. However, the incident 

data that are available suggest that exposure pathways for flufenacet are complete and that 

exposure levels are sufficient to result in field-observable effects. 

5. Risk Characterization 

Risk characterization is the integration of exposure and effects characterization to determine the 

ecological risk from the use of flufenacet and the likelihood of effects on aquatic life, wildlife, and 

plants based on varying pesticide-use scenarios. The risk characterization provides an estimation 

and a description of the risk; articulates risk assessment assumptions, limitations, and 

uncertainties; synthesizes an overall conclusion; and provides the risk managers with information 

to make regulatory decisions.
Page 33 of 118 

5.1. Risk Estimation 

Results of the exposure modeling and toxicity effects data are used to evaluate the likelihood of 

adverse ecological effects on non-target species. For the assessment of flufenacet risks, the risk 

quotient (RQ) method is used to compare exposure and measured toxicity values (refer to 

Appendix G). Estimated environmental concentrations (EECs) are divided by the most sensitive 

acute and chronic toxicity values. The RQs are then compared to the Agency’s levels of concern 

(LOCs). These LOCs, summarized in Appendix G, are the Agency’s interpretive policy and are 

used to analyze potential risk to non-target organisms and the need to consider regulatory action. 

These criteria are used to indicate when a pesticide’s use as directed on the label has the potential 

to cause adverse effects on non-target organisms. 

a) Non-target Aquatic Animals and Plants 

 Acute Risk to Aquatic Animals 

Acute RQs were derived for exposure of freshwater and estuarine/marine fish and invertebrates to 

total toxic residues including the parent a.i. flufenacet and its degradate thiadone (Table 14). No 

acute RQs exceeded the LOCs for acute risk (0.5), acute restricted use (LOC 0.1), or acute listed 

risk (LOC 0.05) for the modeled crops for either the parent a.i. alone, thiadone alone, or the total 

toxic residues resulting from flufenacet application. RQs ranged from <0.01 to 0.01. 

Table 14. Acute RQs for fish and aquatic invertebrates exposed to the 

total toxic residues of flufenacet (parent plus thiadone degradate).

Use/ 

SWCC 

Scenario 

 

Surface 

Water 

EECs 

(Peak) 

FW

Fish  

FW

Invert

SW

Fish

SW

Invert

FW

Fish  

FW

Invert

SW

Fish

SW

Invert

LC /

EC50

LC /

EC50

LC /

EC50

LC /

EC50 RQ RQ RQ RQ

(μg/L) (μg/L) (μg/L) (μg/L) (μg/L)

Corn 

(IL Corn) 26 2260 2800 3380 5,590 0.01 0.01 0.01 0.00

Soybeans 

(MI Beans) 9 2260 2800 3380 5,590 <0.01 <0.01 <0.01 <0.01

Grass Seed 

(OR Grass 

Seed) 

5 2260 2800 3380 5,590 <0.01 <0.01 <0.01 <0.01

Wheat and 

Triticale 

(ND 

Wheat) 

7 2260 2800 3380 5,590 <0.01 <0.01 <0.01 <0.01

 Chronic Risk to Aquatic Animals 
Page 34 of 118 

Chronic RQs were derived for exposure of freshwater fish and invertebrates and estuarine/marine 

invertebrates to total toxic residues that included the parent a.i. flufenacet and its degradate 

thiadone (Table 15). No chronic RQs exceeded the LOC (1) for the modeled crops from either 

the parent a.i. alone (flufenacet), thiadone alone, or the total toxic residues (flufenacet+thiadone) 

resulting from flufenacet application. RQs ranged from <0.01 to 0.48. 

Table 15. Chronic RQs for fish and aquatic invertebrates exposed to the total toxic 

residues of flufenacet (parent plus thiadone degradate).

Use/ 

SWCC 

Scenario

Surface Water 

EECs 

FW

Fish  

FW

Invert

SW

Fish

SW

Invert

FW

Fish  

FW

Invert

SW

Fish

SW

Invert

21-day 60-day NOAEC NOAEC NOAEC NOAEC

RQ RQ RQ RQ (μg/L) (μg/L) (μg/L) (μg/L) (μg/L)

Corn 

(IL Corn) 25 24 75 6300 49 221 0.32 <0.01 0.48 0.11

Soybeans 

(MI 

Beans) 

9 8 75 6300 49 221 0.11 <0.01 0.17 0.04

Grass 

Seed 

(OR 

Grass 

Seed) 

4.3 4.1 75 6300 49 221 0.06 <0.01 0.08 0.02

Wheat 

and 

Triticale 

(ND 

Wheat) 

7 6 75 6300 49 221 0.08 <0.01 0.13 0.03

*Fish toxicity data was compared to the 60 day EEC while the invertebrate toxicity data was compared to the 21 day EEC. 

 Risk to Aquatic Plants 

RQs are first derived for exposure of aquatic plants considering total toxic residues (flufenacet and 

thiadone) (Table 16). RQs exceeded the LOC for both vascular and non-vascular plants for all 

the modeled crops for both the parent a.i. and total toxic residues for both listed and non-listed 

species. RQs for the total toxic residues ranged from 1.6 to 60.2. Given these exceedances, the 

formation-decline method utilized in aquatic exposure estimation allows for further presentation 

of the parent a.i. contribution and thiadone degradate contribution to the overall total toxic residue 

RQ. Flufenacet only and thiadone only RQs are presented in Table 17. The RQs still exceeded 

for the parent a.i. alone ranging from 1.0 to 39.5. However, there were not any LOC exceedances 

for either listed or non-listed aquatic plants when exposed to the degradate thiadone alone with all 

RQs less than 0.01 because thiadone is much less toxic than the parent flufencacet. 
Page 35 of 118 

Table 16. RQs for non-vascular and vascular plants exposed to the total toxic residues of 

flufenacet (parent flufenacet plus thiadone degradate).

Use/ 

SWCC 

Scenario

Peak 

Surface 

Water 

EECs 

(μg/L) 

Toxicity Values (μg/L) RQs

Non‐Vascular

Plant Vascular Plant Non‐VascularPlant Vascular Plant

Non‐

listed   Listed   Non‐listed   Listed   Non‐listed   Listed   Non‐listed   Listed  

EC50 NOAEC EC50 NOAEC EC50 NOAEC EC50 NOAEC

Corn 

(IL Corn) 26 2.90 2.52 2.45 0.44 9.1 10.5 10.8 60.2

Soybeans 

(MI 

Beans) 

9 2.90 2.52 2.45 0.44 3.1 3.6 3.7 20.5

Grass 

Seed 

(OR 

Grass 

Seed) 

5 2.90 2.52 2.45 0.44 1.6 1.8 1.9 10.3

Wheat 

and 

Triticale 

(ND 

Wheat) 

7 2.90 2.52 2.45 0.44 2.3 2.7 2.7 15.2

* RQs exceeding the LOCs shown in bold text. 

Table 17. RQs for non-vascular and vascular plants exposed to the parent a.i. only and 

thiadone degradate only.

Use/ 

SWCC 

Scenario 

Peak 

Surface 

Water 

EECs 

(μg/L) 

Toxicity Values (μg/L) RQs

Non‐Vascular

Plant Vascular Plant Non‐VascularPlant Vascular Plant

Non‐

listed Listed Non‐listed Listed Non‐listed Listed Non‐listed Listed

EC50 NOAEC EC50 NOAEC EC50 NOAEC EC50 NOAEC

Flufenacet (parent only)

Corn 

(IL Corn) 17.4 2.9 2.5 2.5 0.4 6.0 6.9 7.1 39.5

Soybeans 

(MI Beans) 5.6 2.9 2.5 2.5 0.4 1.9 2.2 2.3 12.8

Grass Seed 

(OR Grass 

Seed) 

2.8 2.9 2.5 2.5 0.4 1.0 1.1 1.2 6.5

Wheat and 

Triticale 

(ND Wheat) 

3.9 2.9 2.5 2.5 0.4 1.3 1.5 1.6 8.8
Page 36 of 118 

Table 17. RQs for non-vascular and vascular plants exposed to the parent a.i. only and 

thiadone degradate only.

Use/ 

SWCC 

Scenario 

Peak 

Surface 

Water 

EECs 

(μg/L) 

Toxicity Values (μg/L) RQs

Non‐Vascular

Plant Vascular Plant Non‐VascularPlant Vascular Plant

Non‐

listed Listed Non‐listed Listed Non‐listed Listed Non‐listed Listed

EC50 NOAEC EC50 NOAEC EC50 NOAEC EC50 NOAEC

Thiadone (degradate only)

Corn 

(IL Corn) 9 6400 940 10340 1010 <0.01 <0.01 <0.01 <0.01

Soybeans 

(MI Beans) 3 6400 940 10340 1010 <0.01 <0.01 <0.01 <0.01

Grass Seed 

(OR Grass 

Seed) 

2 6400 940 10340 1010 <0.01 <0.01 <0.01 <0.01

Wheat and 

Triticale 

(ND Wheat) 

3 6400 940 10340 1010 <0.01 <0.01 <0.01 <0.01

* RQs exceeding the LOCs shown in bold text. 

b) Non-target Terrestrial Animals 

 Acute Risk to Birds and Mammals 

Avian Species 

Acute RQs were derived for exposure of birds (Table 18) using toxicity endpoints for the canary 

(MRID 49844202). Dose-based RQs exceeded the endangered species LOC (0.1) for 20g ‘small’ 

birds that feed on short grass and broadleaf plants for all uses of flufenacet (RQs ranged from 0.12 

to 0.48). Dose based RQs for small birds ranged from 0.08 to 0.27 for tall grass and arthropods 

with all uses except for wheat exceeding the endangered species LOC. RQs did not exceed the 

endangered species LOC for fruits/pods. 

Dose-based RQs exceeded the endangered species LOC (0.1) for 100 g ‘medium’ birds that feed 

on short grass for all uses except wheat with RQs ranging from 0.09 to 0.22. The listed species 

LOC (0.1) was also exceeded at the highest application rate used on corn in the tall grass and 

broadleaf plant categories. There were not any other LOC exceedances for any other dietary items 

for medium or large birds. 
Page 37 of 118 

Table 18.  Acute dose‐based RQs for birds due to exposure to proposed uses of flufenacet.

  

Use

(application

rate ‐ lbs

a.i./A)

Small Medium Large

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Corn

(Sweet and

Field)  

(0.8019)

0.48 0.22 0.27 0.03 0.19 0.01 0.22 0.10 0.12 0.01 0.08 <0.01 0.07 0.03 0.04 <0.01 0.03 <0.01

Soybean

(0.4644) 0.28 0.13 0.16 0.02 0.11 0.00 0.12 0.06 0.07 0.01 0.05 <0.01 0.04 0.02 0.02 <0.01 0.02 <0.01

Grass Seed

(0.442) 0.27 0.12 0.15 0.02 0.10 0.00 0.12 0.05 0.07 0.01 0.05 <0.01 0.04 0.02 0.02 <0.01 0.01 <0.01

Wheat and

Triticale

(0.3448)

0.21 0.09 0.12 0.01 0.08 0.00 0.09 0.04 0.05 0.01 0.04 <0.01 0.03 0.01 0.02 <0.01 0.01 <0.01

Acute listed species LOC = 0.1; Acute Restricted Use LOC = 0.2; Non‐listed animals acute LOC = 0.5

* RQs exceeding the LOCs shown in bold text.

Mammalian Species 

Definitive acute dose-based RQ values for mammalian receptors ranged from <0.01 to 0.14 

(Table 19). Based on these results, endangered species LOC (0.1) was exceeded for 15g and 

35g mammals that feed on short grass adjacent to sweet corn and soybeans applications of 

flufenacet. No dietary data were submitted. 

Table 19.  Acute dose based RQs for mammals for flufenacet uses.

  

Use

(application

rate ‐ lbs

a.i./A)

Small Medium Large

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Corn

(Sweet and

Field)  

(0.8019)

0.14 0.06 0.08 0.01 0.06 <0.01 0.12 0.06 0.07 0.01 0.05 <0.01 0.06 0.03 0.04 <0.01 0.03 <0.01

Soybean

(0.4644) 0.08 0.04 0.05 0.01 0.03 <0.01 0.07 0.03 0.04 <0.01 0.03 <0.01 0.04 0.02 0.02 <0.01 0.01 <0.01

Grass Seed

(0.442) 0.08 0.04 0.04 <0.01 0.03 <0.01 0.07 0.03 0.04 <0.01 0.03 <0.01 0.04 0.02 0.02 <0.01 0.01 <0.01

Wheat and

Triticale

(0.3448)

0.06 0.03 0.03 <0.01 0.02 <0.01 0.05 0.02 0.03 <0.01 0.02 <0.01 0.03 0.01 0.02 <0.01 0.01 <0.01
Page 38 of 118 

Table 19.  Acute dose based RQs for mammals for flufenacet uses.

  

Use

(application

rate ‐ lbs

a.i./A)

Small Medium Large

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Seeds

Acute listed species LOC = 0.1; Acute Restricted Use LOC = 0.2; Non‐listed animals acute LOC = 0.5

* RQs exceeding the LOCs shown in bold text.

 Chronic Risk to Birds and Mammals 

Avian Species 

Chronic dietary-based RQs for birds ranged from 0.06 to 2.19 (Table 20). RQs in the short grass 

dietary item exceeded the chronic LOC of 1.0 for all uses except for wheat and ranged from 1.21 

to 2.19. The use rate of corn exceeded the chronic LOC for all dietary items that included short 

grass, tall grass, and broadleaf plants. 

Table 20.  Chronic dietary‐based RQs for birds due to exposure to

proposed uses of flufenacet.

Use

(application rate ‐ lbs a.i./A)

Short Grass

Tall Grass

Broadleaf Plants

Fruits/pods

Arthropods

Corn (Sweet and Field)  

(0.8019) 2.19 1.00 1.23 0.14 0.86

Soybean

(0.4644) 1.27 0.58 0.71 0.08 0.50

Grass Seed

(0.442) 1.21 0.55 0.68 0.08 0.47

Wheat and Triticale

(0.3448) 0.94 0.43 0.53 0.06 0.37

Chronic LOC = 1.0

* RQs exceeding the LOCs shown in bold text.

Mammalian Species 

Chronic dietary-based RQs for mammals ranged from 0.2 to 7.4 (Table 21). The chronic RQs for 

flufenacet uses on corn, soybean, grass seed, and wheat triticale (application rates ranging from 

0.3448 lbs a.i./A to 0.8019 lbs a.i./A) exceeded the chronic LOC for all dietary items but 

fruits/pods. 
Page 39 of 118 

Table 21. Chronic dietary based RQs for mammals due to exposed to proposed uses of

flufenacet.

Use (application rate ‐ 

lbs a.i./A)

Short Grass

Tall Grass

Broadleaf

Plants

Fruits/pods

Arthropods

Corn (Sweet and Field)  

0.8019 7.4 3.4 4.2 0.5 2.9

Soybean (0.4644) 4.3 2.0 2.4 0.3 1.7

Grass Seed 0.442 4.1 1.9 2.3 0.3 1.6

Wheat Triticale (0.3448) 3.2 1.5 1.8 0.2 1.2

Chronic LOC = 1.0

All values are chronic values

* RQs exceeding the LOCs shown in bold text.

 Risks to Piscivorous Birds and Mammals 

Given the indications that flufenacet residues will bioaccumulate in the tissues of exposed fish, 

there is the potential for flufenacet exposure to piscivorous birds and mammals through diet. 

KABAM v.1.0 was run on the use which resulted in the highest exposure in the environment (corn, 

application rate = 0.8019 lbs. a.i./A – see Table 3). There were not any acute or chronic 

exceedances that resulted from the highest application rates of flufenacet. The resulting acute and 

chronic RQs are all <0.01 for piscivorous birds and ranged from <0.01 for acute exposure to 0.2 

for dose based chronic exposure for piscivorous mammals. The KABAM run can be accessed in 

Appendix F. These minimal impacts are expected given flufenacet’s moderate log Kow of 3.20 

and BCF of 103X. 

c) Risk to Non-target Terrestrial Plants 

There are seven studies that are still in review that examine the toxicity of flufenacet and coformulations of flufenacet and other active herbicidal ingredients on both vegetative vigor 

(Guideline number 850.4250) and seedling emergence (Guideline number 850.4225) of terrestrial 

plant species. These studies examine Flufenacet SC500 (MRIDs 48897605 and 48897609), 

Flufenacet & Isoxaflutole WG 58 (MRIDs 48897606 and 48897610), Flufenacet and Isoxaflutole 

SC 480 (MRIDs 48897607 and 48897611), and Axiom 68DF (MRID 48897688). The results of 

these studies may indicate that formulated products may be more or less toxic to terrestrial plant 

species than the terrestrial plants studies currently used in this preliminary risk assessment and 

may result in buffers of different widths necessary to mitigate risk. Results of these studies will 

be incorporated into the final risk assessment when the results become available. 

RQs resulting from off-site transport from runoff and spray drift of flufenacet are presented below. 

In general, monocots were more sensitive to flufenacet than dicots. RQs ranged from 0.6 to 25.5 

for monocots and from 0.2 to 14.6 for dicots. 

The risk resulting from the movement of flufenacet residues to irrigation water that may be applied 

to non-target plants and crops is discussed in the Risk Description Section (Section 5.2). Exposure 
Page 40 of 118 

estimates for this exposure pathway are based on peak flufenacet surface water column 

concentrations as presented in Table 3 for each use. 

Monocotyledon Species 

RQs for monocots ranged from 0.6 to 22.1. Uses on corn (application rates 0.8019) exceeded 

both the listed and non-listed LOC of 1.0 for every scenario modeled (Table 22). Uses on soybean, 

grass seed, and wheat (application rates 0.4644, 0.442, 0.3448 lbs a.i./A respectively) exceeded 

the listed species LOC for every scenario modeled and non-listed species’ LOC for both the runoff 

and spray drift in both dry and semi-aquatic areas. 

Table 22. Monocot RQs from applications of flufenacet in the modeled 

scenarios of Runoff and Spray Drift in Dry areas, Runoff and Spray 

Drift in Semi-Aquatic Areas, and Spray Drift only.

Use

(application rate ‐ 

lbs a.i./A)

Monocot RQ Values

Runoff and   Runoff and  

Spray Drift   Spray Drift Spray Drift Only

(Dry Areas) (Semi‐Aquatic Areas)

Nonlisted

Species

Listed

Species1

Nonlisted

Species

Listed

Species1

Nonlisted

Species

Listed

Species

Corn (Sweet and

Field)   

(0.8019)

2.7 4.0 14.7 22.10 1.3 2.0

      

Soybean  

(0.4644) 1.5 2.3 8.5 12.8 0.8 1.2

Grass Seed  

(0.442) 1.5 2.2 8.1 12.2 0.7 1.1

Wheat and

Triticale  

(0.3448)

1.7 2.6 12.1 18.1 0.6 0.9

* RQs exceeding the LOCs shown in bold text.

Dicotyledon Species 

RQs for dicots ranged from 0.02 to 14.6 (Table 23). Use on corn (application rate = 0.8019 lbs 

a.i./A) exceeded the listed species LOC for every scenario modeled. The non-listed species LOC 

was only exceeded for corn in the runoff and spray drift in semi-aquatic areas scenario. For use 

on soybeans, grass seed, and wheat (application rates 0.46, 0.442, 0.3448 lbs a.i./A respectively) 

RQs ranged from 0.2 to 10.3. RQs exceeded the listed species LOC for only the runoff and spray 

drift in dry and semi-aquatic areas but not in the spray drift only scenario. The RQ from soybean 

and grass seed applications exceeded the non-listed species LOC only in the runoff and spray drift 

in semi-aquatic areas scenario. 
Page 41 of 118 

Table 23. Dicot RQs from applications of flufenacet in the modeled 

scenarios of Runoff and Spray Drift in Dry areas, Runoff and Spray 

Drift in Semi-Aquatic Areas, and Spray Drift only.

Use

(application rate ‐ 

lbs a.i./A)

Monocot RQ Values

Runoff and   Runoff and  

Spray Drift   Spray Drift Spray Drift Only

(Dry Areas) (Semi‐Aquatic Areas)

Nonlisted

Species

Listed

Species1

Nonlisted

Species

Listed

Species1

Nonlisted

Species

Listed

Species

Corn (Sweet and

Field)   

(0.8019)

0.7 2.3 4.0 12.6 0.4 1.1

Soybean  

(0.4644) 0.4 1.3 2.3 7.3 0.2 0.7

Grass Seed  

(0.442) 0.4 1.3 2.2 6.9 0.2 0.6

Wheat and

Triticale  

(0.3448)

0.5 1.5 3.3 10.3 0.2 0.5

* RQs exceeding the LOCs shown in bold text.

d) Risk to Terrestrial Invertebrates 

Bees may be exposed to flufenacet via direct applications, drift from boom or aerial spray, or from 

residues on treated crops. There are no any acute or chronic toxicity studies submitted for larval 

bees or chronic feeding studies for adult bees. Therefore, RQs resulting from only contact 

exposure to flufenacet residues are presented in Table 24. The RQs are less than values because 

the toxicity endpoint did not show any toxicity at the highest concentrations tested. Using these 

values the RQ is not expected to be higher than those report for acute contact exposure. 
Page 42 of 118 

Table 24. Contact RQs for bees that result from 

applications of flufenacet.

Use (Application Rate

‐ lbs a.i./A) Contact RQs

Corn (Sweet and Field)

(0.8019) <0.09

Soybean  

(0.4644) <0.05

Grass Seed  

(0.442) <0.05

Wheat & Triticale  

(0.3448) <0.04

Acute LOC for bees is 0.4.

Using calculations from Bee-Rex modeling, the RQs for contact ranged from <0.04 to <0.09 which 

were below the Agency’s established LOC of 0.4. Based on this, the risk from contact exposure 

is expected to be low. The timing of application may also reduce exposure to pollinators if early 

in the growing season when plants are not flowering. There was not an acute oral study submitted 

for flufenacet. If the endpoint was similar to that of the contact study (>25 g/bee) which was 

practically non-toxic RQs would range from <0.4 to <1.0. 

5.2. Risk Description 

5.2.1 Risk to Non-Target Aquatic Organisms 

Aquatic Animals 

The acute studies that test the toxicity of TGAI to freshwater and estuarine/marine fish and 

invertebrates, indicate that flufenacet is slightly to moderately toxic on acute basis. This coupled 

with low estimated aquatic concentrations results in RQs below the level of concern for these taxa. 

Risk estimates for freshwater and estuarine/marine fish and invertebrates show that flufenacet does 

not pose acute risks to these taxa (Table 14). It also does not pose indirect risk for non-listed or 

listed species that rely on them as a food source. In addition, results of studies testing toxicity of 

aquatic animals to thiadone, show that thiadone is as toxic as or less toxic than the parent. 

Therefore, the risk to thiadone will likely be low as well. 

The chronic studies that test the toxicity of TGAI to these organisms showed higher toxicity; 

however, due to the low levels of flufenacet estimated to contaminate waterways, RQs were low 

and showed no chronic risk to freshwater fish and freshwater and estuarine/marine invertebrates 

(Table 15) 

Based on the available data, the potential for acute and chronic risks to aquatic animals is low. 

However, a potential for indirect effects to these species does exist because of the high risks to 

aquatic plants (see below). Many aquatic animals are directly and/or indirectly dependent upon 

aquatic plants for food and/or shelter during various life-stages. 
Page 43 of 118 

Aquatic Plants 

Based on data and the predicted aquatic exposures, there is potential risk to non-listed and listed 

vascular and non-vascular plant species (Table 16). RQs were exceeded for listed and non-listed 

vascular and non-vascular plants for all crop uses modeled for the total toxic residues flufenacet 

and its thiadone degradate. However given these exceedances, RQs calculated from flufenacet 

and thiadone specific EECs are further explored. RQs resulting from exposure to thiadone alone 

did not result in any LOC exceedance for either listed or non-listed species from any use that was 

modeled due to thiadone being less toxic than the parent flufenacet compound (Table 17). 

Since flufenacet is applied as a spray, non-target aquatic plants may come into contact with 

flufenacet and its degradates in runoff or spray drift. Flufenacet’s moderate mobility suggests that 

it does have the ability to be transported via runoff and erosion to water systems. Several small 

detections and one large detection of flufenacet up to 75 ppb in surface water monitoring data 

provides evidence supporting this exposure scenario. In addition, since this product is a 

preplant/pre-emergent herbicide, there will be little vegetation on the field to filter the drift 

movement of the spray droplets. Once in the water, flufenacet is stable to hydrolysis and 

photolysis. Thiadone, the metabolite of concern is also stable to hydrolysis and is persistent in 

aquatic conditions. Therefore, if flufenacet enters water systems, non-target aquatic plants may 

be at risk. 

Overall, the contribution of spray drift to the overall risk to aquatic plants is small. This is due to 

flufenacet’s ability to runoff in large quantities in the areas of the country that it used. Furthermore, 

ground spray applications which are used in the vast majority of flufenacet uses limit the overall 

impacts from spray drift. Table 25 shows the RQs which result from runoff impacts only. Risks 

remain for vascular listed species with all flufenacet uses. Figures 3, 4, 5, and 6 show only slight 

reductions to RQs when spray drift is eliminated with the corn, soybean, wheat/triticale, and grass 

seed uses with ground spray applications. . However, RQs still remain above the LOCs for all 

uses except for the grass seed use where RQs fall below the LOCs when spray drift has not impact 

with non-listed and listed non vascular plants and non-listed vascular plants. Given that runoff 

appears to drive the risk to all aquatic plants for all of the uses for many cases, spray drift buffer 

zones are not likely to result in substantial mitigation of the risk which is found for aquatic plants. 

It is possible that spray drift may drive the risk in other regions not shown herre, particularly in 

the Western U.S. over drier areas where flufenacet is applied. However, exploratory analysis using 

the AgDrift model indicates that spray drift buffer zones required to mitigate the risk extend 

beyond 1,000 feet and therefore are not feasible to implement. 

Table 25. Runoff-only risk quotients and resulting risk conclusions due to flufenacet and 

thiadone exposure to aquatic plants. 

Use

Risk Quotients and Remaining Risk Conclusions Without Spray 

Drift (Yes/No) 

Non-Vascular 

Non-Listed 

Non-Vascular 

Listed 

Vascular 

Non-Listed 

Vascular 

Listed 

Corn 7.4 (Yes) 8.6 (Yes) 8.8 (Yes) 49.2 (Yes) 

Soybean 1.9 (Yes) 2.2 (Yes) 2.3 (Yes) 12.6 (Yes) 

Wheat/Triticale 0.6 (No) 0.7 (No) 0.8 (No) 4.1 (Yes) 
Page 44 of 118 

Table 25. Runoff-only risk quotients and resulting risk conclusions due to flufenacet and 

thiadone exposure to aquatic plants. 

Use

Risk Quotients and Remaining Risk Conclusions Without Spray 

Drift (Yes/No) 

Non-Vascular 

Non-Listed 

Non-Vascular 

Listed 

Vascular 

Non-Listed 

Vascular 

Listed 

Grass Seed 1.5 (Yes) 1.8 (Yes) 1.8 (Yes) 10.1 (Yes) 

Figure 3. Comparison of total runoff and spray-drift RQs and runoff-only RQs for non 

vascular, non-listed aquatic plant species. 

0

10

20

30

40

50

60

70

Corn Forestry Soybeans Grass Seed Wheat and Triticale

Risk Quotients

Overall Contribution of Spray Drift on Non Vascular Aquatic Plant

Non‐Listed Species Risk Quotients for Flufenacet Uses

RQ's:  Runoff and

Spray Drift

RQs:  Runoff and

No Spray Drift

LOC
Page 45 of 118 

Figure 4. Same as figure 3 except for non vascular, listed aquatic plant species. 

0

10

20

30

40

50

60

70

Corn Forestry Soybeans Grass Seed Wheat and Triticale

Risk Quotients

Overall Contribution of Spray Drift on Non Vascular Aquatic Plant

Listed Species Risk Quotients for Flufenacet Uses

RQ's:  Runoff and

Spray Drift

RQs:  Runoff and

No Spray Drift

LOC
Page 46 of 118 

Figure 5. Same as figure 3 except for vascular, non-listed aquatic plant species. 

0

10

20

30

40

50

60

70

Corn Forestry Soybeans Grass Seed Wheat and Triticale

Risk Quotients

Overall Contribution of Spray Drift on Vascular Aquatic Plant

Non‐Listed Species Risk Quotients for Flufenacet Uses

RQ's:  Runoff and

Spray Drift

RQs:  Runoff and

No Spray Drift

LOC
Page 47 of 118 

Figure 6. Same as figure 3 except for vascular, listed aquatic plant species. 

5.2.2 Risk to Non-Target Terrestrial Organisms 

The nature of the magnitude and duration of risk resulting from acute and chronic exposure via 

intake of flufenacet residues for birds and mammals is discussed below. Based on the nature of 

pre-emergent applications with flufenacet, the most direct risks will result from ingestion of 

arthropods and seeds possessing flufenacet residues. Risks are further plausible given 

flufenacet’s moderate persistence in terrestrial environments (half-lives ranging between 23.1 – 

63.6 days). 

Additional risks with broadleaf plants (not associated with crops) as well as short grass and long 

grass containing flufenacet residues are also possible with spray drift to areas containing grass 

offsite from the treated cultivated area. However, the exact contribution due to spray drift is not 

explicitly quantified in TREX. 

0

10

20

30

40

50

60

70

Corn Forestry Soybeans Grass Seed Wheat and Triticale

Risk Quotients

Overall Contribution of Spray Drift on Vascular Aquatic Plant

Listed Species Risk Quotients for Flufenacet Uses

RQ's:  Runoff and

Spray Drift

RQs:  Runoff and

No Spray Drift

LOC
Page 48 of 118 

Birds 

 Acute Risk (Oral-based)

Based on the submitted acute oral toxicity studies on birds and mammals, flufenacet is categorized 

as moderately toxic to birds on an acute oral basis. The LD50 for the canary was determined to be 

461 mg ai/kg bw (MRID 49844202). There were not any exceedances above the acute level of 

concern (0.5) for non-listed species. For listed species however, there were numerous RQs for 

small birds that exceeded the listed species LOC of 0.1. All proposed uses of flufenacet resulted 

in dose-based RQs that exceeded the endangered species LOC of 0.1 in small birds feeding on 

short grass and broadleaf plants. Medium sized birds feeding on short grass at all application 

rates, broadleaf plants at the two highest application rates, and tall grass at the highest application 

rate, exceeded the listed species LOC as well (Table 18). 

While acute risk is determined by examining upper-bound residue levels, birds exposed to residues 

at a magnitude comparable to mean residue levels left on food items would pose less risk to both 

size classes of birds. At the two highest application rates, RQs derived from mean residue levels 

do not exceed any LOCs for medium sized birds and only exceed the listed species LOC for small 

birds for short grass and arthropods (RQ range from 0.11 and 0.17). At the two highest application 

rates, short grass residues would take roughly 33 and 41 days, and broadleaf plants 4 and 12 days, 

for the residues to drop below the Agency’s LOC for listed species. 

 Chronic Risk (Dietary-based) 

Chronic dietary risk was identified for birds consuming short grass, tall grass and broadleaf plants 

at the highest application rates (RQs = 2.19, 1.0, 1.23 respectively). Risk was also identified from 

consumption of short grass from soybean and grass seed applications (RQs 1.27 and 1.21 

respectively) (Table 20). These RQs are based on a reproduction study that shows increase in 

number of eggs cracked and decrease in normal hatchlings and survivors. Based on the toxic 

effects on birds and the RQs that exceed the LOC, chronic risk to birds exist when feeding around 

flufenacet application sites. 

Mammals 

 Acute Risk (Oral-based)

There was not any risk identified for non-listed mammals of any size. RQs did however exceed 

the listed species LOC for both small and medium sized mammals for the two highest application 

rates (ranging from 0.1 to 0.14) when consuming short grass. Examination of RQs that result from 

mean residues on these food items did not exceed any LOCs (Table 19). 
Page 49 of 118 

 Chronic Risk (Dietary-based) 

Relative to the use patterns identified in this assessment, exposure of flufenacet spray application 

is expected to result in chronic risk to mammals. As shown in Table 21, most dose-based RQs for 

chronic risk to mammalian species are above the chronic risk LOC (1) for all maximum spray 

application scenarios considered in this risk assessment (RQ range = 0.18 to 64.22). Specifically, 

chronic dose-based RQs exceed the LOC for mammals feeding on short grass (RQ range = 12.6 

to 64.22), tall grass (RQ range = 5.8 to 29.43), broadleaf plants (RQ range = 7.11 to 36.12), and 

fruits/pods (RQ range = 0.79 to 4.1), arthropods (RQ range = 4.95 to 25.2), and seeds (RQ range 

(0.18 to 0.89) for all modeled crop scenarios. 

In addition, chronic dietary-based RQs exceed the chronic LOC for all modeled scenarios for 

mammals feeding on short grass (RQ range = 3.2 to 7.4), tall grass (RQ range = 1.5 to 3.4), and 

broadleaf plants (RQ range = 1.8 to 4.2) and arthropods (RQ range = 1.2 to 2.9). Mammalian RQs 

are based on a 2-generation reproduction study that shows evidence of dose-related decreases in 

litter size, pup viability, and pup body weight. 

Based on the toxic effects on reproduction in mammals and the high RQ values, chronic risk to 

mammals from application of flufenacet is high, especially since some of the proposed applications 

of flufenacet may occur during the spring/summer, coinciding with the reproductive season for 

most animals. 

In addition, the metabolite of flufenacet, thiadone, has been identified as toxic to mammals and 

birds. However, since thiadone has a short aerobic soil half-life (2.0-2.8 days) and is highly 

mobile, it may not be available to terrestrial animals on a long-term basis, decreasing the chronic 

risk to these species. 

To bound the estimates of risk to mammals and birds resulting from chronic exposure to flufenacet, 

RQs using mean Kenaga residue values in addition to upper-bound values were calculated. Using 

the non-conservative mean residue values, implying that higher predicted residue values are 

expected half the time, for all modeled scenarios, dose-based RQs for all sizes of mammals feeding 

on short grass, tall grass, and broadleaf plants (RQ range = 1.9 to 22.75) still exceed the chronic 

LOC; however, for mammals that feed on fruits/pods, there are fewer exceedances with mean 

residues (only for 15g and 35g mammals feeding on fruits/pods for the sweet corn modeled 

scenario and 15g mammals that feed on fruits/pods (RQ = 1.08) for the grass modeled scenario). 

There are also fewer exceedances for the dietary RQs for mammals with short grass and arthropods 

exceeding the chronic LOC for the third highest application rate and only short grass exceeding at 

the lowest application rate. 

Piscivorous Birds and Mammals 

There were no exceedances to piscivorous birds or mammals feeding on fish containing flufenacet 

and thiadone residues. The resulting acute and chronic RQs are <0.01 for piscivorous birds. Acute 

RQs for piscivorous mammals was also <0.01 while chronic RQs for piscivorous mammals ranged 

from 0.02 to 0.2. Likely reasons for marginal impacts include flufenacet’s relatively low 

application rate and log Kow 3.2 value indicating a marginal potential for flufenacet residues to 
Page 50 of 118 

bind to fatty tissues. While BCF values are as high as 103X, 98 percent of flufenacet and other 

radioactive residues depurated within 15 days after exposure 103X (MRID Nos. 43441127 and 

43441139). 

Terrestrial Invertebrates 

Results of the acute contact toxicity studies with honey bees demonstrate that flufenacet TGAI is 

practically non-toxic to beneficial insects on an acute basis (LD50 > 25 μg a.i./bee). RQs for 

acute risk are below 0.09 which is below the LOC of 0.4 (Table 24). Therefore, non-target 

insects are at low risk through acute contact exposure from application to flufenacet. However, 

there is a potential for indirect risk due to the high toxicity of flufenacet to terrestrial plants. 

Many invertebrates rely on plants during a part of their life cycles. Data concerning chronic 

exposure to adult and larval honeybees as well as acute exposure to larval honeybees is also 

lacking so there is more uncertainty as to the risk from other exposure routes to flufenacet. 

Terrestrial Plants 

 Runoff and Spray Drift Exposure 

Current terrestrial phytotoxicity data and the predicted exposures from the TerrPlant model 

generally indicate that there is risk to non-listed and listed monocot and dicot terrestrial and semiaquatic plant species. Data from a Tier-2 vegetative vigor study indicate that the most sensitive 

monocot was sorghum with an EC25/NOAEC of 0.017/0.008 lbs a.i./A and the most sensitive dicot 

was cucumber with an EC25/NOAEC of 0.032/0.016 lbs a.i./A. The calculated risk quotients for 

terrestrial and semi-aquatic plants do exceed the level of concern for most listed and non-listed 

terrestrial plants in adjacent areas and semi-aquatic areas (RQ range = 0.2 to 25.5; Tables 22 and 

23), indicating risk to terrestrial plants. 

To further analyze the potential risk from flufenacet use to non-target plants, the AgDrift model 

was used to predict spray drift deposition, and to determine the distance from the edge of the 

treated site where the risk from spray drift alone is equal to the LOC for listed and non-listed 

plants. It is important to recognize, though, that risk from runoff is not considered in this analysis. 

However, risk to plants from spray applications may also be reduced through the incorporation of 

spray drift buffers. In this analysis, the buffer distances to where the spray drift deposition fraction 

equals the vegetative vigor EC25 for evaluating risk to non-listed plants as well as the distance 

where the spray drift deposition fraction equals the vegetative vigor NOAEL for evaluating risk to 

listed plants are determined. Beyond these distances, the risk from spray drift alone is not expected 

to exceed the LOC. Table 26 and Table 27 provide buffer distances for both monocots and dicots 

respectively using the default droplet size distributions in the AgDRIFT model for both ground 

and aerial applications (droplet sizes per the American Society of Agricultural and Biological 

Engineers or ASABE: very fine to fine for ground applications and fine to medium for aerial 

applications). This is done since flufenacet labels do not specify droplet size distributions. Ground 

applications are modeled with both high and low boom applications (1.27 and 0.5 meters above 

the ground respectively). 

For monocots, spray drift buffer distances that resulted from low boom ground applications ranged 
Page 51 of 118 

from 20 feet for non-listed species at the lowest application rate, to 95 feet for listed species 

exposed to the highest application rates (Table 26). These spray drift buffer distances increase for 

high boom applications and ranged from 52 feet for non-listed species at the lowest application 

rate to 236 feet for listed species at the highest application rate. Spray drift buffer distances to 

mitigate risk for monocots from aerial applications were 374 and 988 feet for non-listed and listed 

species respectively (Table 26). 

Table 26. Modeled spray drift buffer distances needed to mitigate risk to the most 

sensitive monocot species for applications with very fine to fine droplet size 

spectrum (ground applications) and fine to medium droplet size spectrum (aerial 

applications). 

Use 

(application 

rate - 

SPRAY DRIFT BUFFER DISTANCES 

 lbs a.i./A) Very Fine to Fine Droplet Spectrum Fine to Medium 

Droplet Spectrum 

   Ground High Boom Ground Low Boom 

Aerial    (1.27 m height) (0.5 m height) 

   Nonlisted Listed Nonlisted Listed Nonlisted Listed 

Corn (Sweet 

and Field) 118 236 43 95 NA NA 

-0.8019 

Soybean 69 144 26 52 NA NA 

-0.4644 

Grass Seed 

66 138 26 49 NA NA 

-0.442 

Wheat & 

Triticale 

(0.3448) 

52 108 20 39 NA NA 

MONOCOT EC25 = 0.017 lbs. a.i./A; NOAEC = 0.008 lbs. a.i./A 

*NA means not applicable since application method is not allowed for use as per 

product labels. 

For dicots, spray drift buffer distances that resulted from low boom ground applications ranged 

from 13 feet for non-listed species at the lowest application rate to 46 feet for listed species 

exposed to the highest application rates (Table 27). These buffer distances increased for high 

boom applications and ranged from 30 feet for non-listed species at the lowest application rate to 

125 feet for listed species at the highest application rates. Spray drift buffer distances to mitigate 

risk for dicots from aerial applications were 200 and 400 feet for non-listed and listed species 

respectively (Table 27). 
Page 52 of 118 

Table 27. Modeled spray drift buffer distances needed to mitigate risk to the 

most sensitive dicot species for applications with very fine to fine droplet 

size spectrum (ground applications) and fine to medium droplet size 

spectrum (aerial applications). 

Use 

(application 

rate - lbs 

a.i./A) 

SPRAY DRIFT BUFFER DISTANCES 

Very Fine to Fine Droplet Size 

Spectrum 

Fine to Medium 

Droplet Size 

Spectrum 

Ground High 

Boom 

Ground Low 

Boom Aerial 

(1.27 m height) (0.5 m height) 

Nonlisted Listed Nonlisted Listed Nonlisted Listed 

Corn (Sweet 

and Field) 66 125 23 46 NA NA 

-0.8019 

Soybean 39 72 13 26 NA NA 

-0.4644 

Grass Seed 

36 69 13 26 NA NA 

-0.442 

Wheat & 

Triticale 

(0.3448) 

30 56 13 20 NA NA 

DICOT EC25 = 0.032 lbs. a.i./A; NOAEC = 0.016 lbs. a.i./A 

*NA means not applicable since application method is not allowed for use as per 

product labels. 

The AgDRIFT model was also run with the coarsest droplet sizes for both ground and aerial 

applications in order to evaluate spray drift buffer distances with larger droplet sizes which may 

be more common with pre-emergent herbicide applications and to explore the narrowest buffers 

possible to mitigate the risks due to spray drift with the current flufenacet uses. The spray drift 

buffer distances required to mitigate risk for ground applications with fine to medium/coarse 

droplet sizes (DV0.5 droplet size = 341 microns) with a low boom range from 6.6 feet for non-listed 

monocot species to 36 feet for listed monocot species and the lowest and highest application rates 

respectively (Table 28). The buffer distances required to mitigate risk for ground applications 

with a low boom range from 3.3 feet for non-listed dicot species to 16 feet for listed dicot species 

and the lowest and highest application rates respectively (Table 29). . Tables 28 and 29 also 

provide buffer distances for a high boom scenario as well since labels often say to position height 

of boom for uniform coverage but to limit drift. 

The spray drift buffer distance estimates provided in Tables 28 and 29 are the narrowest buffers 

that can be achieved assuming adequately large spray droplets (DV0.5 droplet size of 341 micron 

droplets) and low enough boom heights for monocots and dicots respectively. The aerial spray 

buffer estimates assume the coarsest droplet sizes (mean droplet size of 450 microns). Spray 
Page 53 of 118 

applications that use a finer droplet size in any application will have significantly larger buffer 

distances in order to mitigate risk to non-target plants. 

Table 28. Modeled spray drift buffer distances needed to mitigate risk to 

the most sensitive monocot species for applications with fine to medium 

coarse droplet sizes (ground applications) and coarse to very coarse droplet 

sizes (aerial applications). 

Use 

(application 

rate - 

lbs a.i./A) 

SPRAY DRIFT BUFFER DISTANCES 

Fine to Medium Coarse Droplet Size 

Spectrum 

Fine to Medium 

Droplet Size 

Spectrum 

Ground High 

Boom 

(1.27 m height) 

Ground Low 

Boom 

(0.5 m height) 

Aerial 

Nonlisted Listed Nonlisted Listed Nonlisted Listed 

Corn (Sweet 

and Field) 

(0.8019) 

26 66 16 36 NA NA 

Soybean 13 33 10 20 NA NA 

-0.4644 

Grass Seed 

13 33 10 20 NA NA 

-0.442 

Wheat & 

Triticale 10 23 7 13 NA NA 

-0.3448 

MONOCOT EC25 = 0.017 lbs. a.i./A; NOAEC = 0.008 lbs. a.i./A 

*NA means not applicable since application method is not allowed for use as per 

product labels. 
Page 54 of 118 

Table 29. Modeled spray drift buffer distances needed to mitigate risk to 

the most sensitive dicot species for applications with fine to medium coarse 

droplet sizes (ground applications) and coarse to very coarse droplet sizes 

for (aerial applications). 

Use 

(application 

rate 

 - lbs a.i./A) 

SPRAY DRIFT BUFFER DISTANCES 

Fine to Medium Coarse Droplet Size 

Spectrum 

Fine to Medium 

Droplet Size 

Spectrum 

Ground High 

Boom 

(1.27 m height) 

Ground Low 

Boom 

(0.5 m height) 

Aerial 

Nonlisted Listed Nonlisted Listed Nonlisted Listed 

Corn (Sweet 

and Field) 

13 26 10 16 NA NA 

-0.8019 

Soybean 7 16 7 10 NA NA 

-0.4644 

Grass Seed 

7 13 7 10 NA NA 

-0.442 

Wheat & 

Triticale 

7 10 3 7 NA NA 

-0.3448 

DICOT EC25 = 0.032 lbs. a.i./A; NOAEC = 0.016 lbs. a.i./A 

**NA means not applicable since application method is not allowed for use as 

per product labels. 

In general, it should be emphasized that the highest spray drift exposure and resulting buffer zones 

occur with flufenacet’s corn. Flufenacet is only applied via ground spray or surface applications 

for corn, but it possesses the highest maximum application rate (0.8019 lbs.a i./A). Buffer zones 

for ground spray are lower than buffer zones for corn as expected given its lower maximum 

application rate. These buffer zones only mitigate risk from spray drift and don’t take into account 

other exposure routes like runoff. 

 Exposure from Application of Irrigation Water Containing Flufenacet Residues 

There may also be risk to plants with application of irrigation water (both ground water and surface 

water) containing flufenacet residues given its herbicidal properties. Such exposure may occur 
Page 55 of 118 

with flufenacet’s ability to transport to surface water and ground water sources via runoff, erosion, 

and leaching as demonstrated through various water monitoring studies as well as upper-bound 

estimated exposure in surface and ground water (see Table 17. for the presentation on surface 

water exposure estimation using the SWCC and Appendix D for the presentation on ground water 

exposure estimation using PRZM-GW). For flufenacet, surface water EECs are higher than 

ground water. Therefore, peak EECs for flufenacet only in the surface water column as presented 

in Table 17 (EEC = 17.4 g/L = 17.4 ppb, SWCC IL Corn Scenario) serves as the preliminary 

basis for deriving equivalent EECs to plants impacted via this exposure occurring associated with 

irrigation practices. To estimate exposure to plants when irrigation from surface water sources are 

contaminated with flufenacet, it was assumed that a field is irrigated with one acre-inch of water 

containing residues. One acre-inch of irrigation water is equivalent to 6,272,640 cubic inches. 

Therefore, a 1 acre field with 1 inch of water has 3,630 cubic ft, of water (6,272,640 cubic inches 

x 0.00058 cubic ft/cubic inch), which is equivalent to 27,156 gallons of water (3,630 cubic ft x 

7.481 gallons/cubic ft). Therefore, 1 inch of water on the 1 acre field weighs 226,625 lbs (27,156 

gallons x 8.3453 lbs/gallon of water). Hence, the estimated exposure concentration for terrestrial 

plants considering flufenacet upper-bound concentrations found in surface water is given as 

follows: 

Plant	EEC	 ቀ୪ୠୱ.ୟ.୧.

୅ ቁ ൌ SWCC	EEC	ሺppbሻx	Conversion	factorሺ ୤୰ୟୡ୲୧୭୬ଵ,଴଴଴,଴଴଴,଴଴଴ሻ	x	Water	Weight	 ୪ୠୱ.୅

= 

17.4	ppb

1,000,000,000 	x	

226,625	lbs. HଶO

ۯܑ./ .܉ .ܛ܊ܔ	૝ૢ૜૙૙ .૙ ൌ 	 A

The resulting RQ based on the most-sensitive endpoint for monocots (RQ= EEC/NOAEC = 

0.00394 lbs. a.i./A ÷ 0.0080 lbs. a.i./A = 0.49) is below the LOC (LOC =1) for both listed and nonlisted plants. For dicots, the RQs are also below both LOCs based on its most sensitive endpoint 

(RQ= EEC/NOAEC = 0.00394 lbs. a.i./A ÷ 0.016 lbs. a.i./A = 0.26). In addition, it appears that 

risks are more certainly higher with the runoff and spray drift exposure scenarios for plants based 

on the RQs (range of between 0.26 – 0.49) shown in this section above as compared to RQs (range 

of 1.5 – 22 for listed plants and 0.40 – 14.7) presented with spray drift and runoff exposure 

examined in Section 5.1. 

5.2.3 Uncertainties, Assumptions, and Limitations 

 Environmental Fate 

The environmental fate database for flufenacet is complete with no major data gaps identified. 

One source of uncertainty related to the behavior of flufenacet in the environment relates to 

unextractable residues observed in excess of 10 percent of applied over multiple soils in aerobic 

soil metabolism studies and multiple water-sediment systems in aerobic aquatic metabolism 

studies (refer to Appendix C which shows the distribution of all material from flufenacet applied 

in soil and water laboratory fate studies). Despite this uncertainty, this risk assessment did not 

evaluate this unextracted residues as part of the consideration for total toxic residues. The overall 

risk conclusions are not likely to change accounting for this uncertainty given that risk quotients 

are very low for aquatic animals (acute RQs< 0.01, chronic RQs<0.48) which are all well below 
Page 56 of 118 

the listed species LOCs, but much larger for aquatic plants resulting in risks of concern broadly 

with all uses aquatic plants, especially with listed species. This is consistent with flufenacet’s 

expected mode of action as an herbicide. 

The second main uncertainty is related to the biodegradation of thiadone in water. While relatively 

persistent, the half-lives for thiadone are determined to be greater than 160 days in the aerobic 

aquatic environment and 303 days in the anaerobic aquatic environment (MRID Nos. 45796111 

and 45796110). Observed DT50s appeared to be close to those values in both studies. However, 

the source of uncertainty is related to incomplete material balances in both studies (below 90 

percent of applied thiadone at some sampling intervals). However, this uncertainty is not very 

substantial considering that minimum material balances ranged between 83.9 – 76.6 percent of 

applied thiadone. Despite this uncertainty, the 160 day half-life value and 303 day half-life value 

was input for the thiadone degradate into the SWCC (Table 1). However, since these are long 

half-lives, and the uncertainty related to incomplete material balances is small, relatively small 

differences in thiadone exposure estimates are expected for acute (peak) and chronic (24-day and 

60-day average) surface water concentrations if there was more certainty with these factors. 

 Ecological Effects 

The ecological effects data are largely complete. The majority of data gaps identified in the 

problem formulation have been submitted and classified as acceptable and are suitable for risk 

assessment purposes. 

 Aquatic Exposure 

In general, upper-bound aquatic exposure estimates for flufenacet and its thiadone degradate 

presented in this risk assessment likely accurately reflect where flufenacet is used with high 

certainty given its few registered uses and since its usage is confined to a specific area of the 

country. Flufenacet usage is confined to the corn and soybean belt of the Midwest, North Carolina, 

Southern High Plains, and Oregon. 

Surface water upper-bound exposure estimates are generally higher by a large margin than the 

highest water monitoring concentrations observed. This may be due to a wide number of factors 

relating to lower vulnerabilities with rainfall, runoff, and drainage that may have been present at 

the surface water monitoring sites since the modeling scenarios depict vulnerable sites. 

Furthermore, it is a likelihood that surface water monitoring are not spatially or temporally targeted 

to applications especially as evident in their irregular sampling intervals in many cases. 

However, it should be noted that there was one isolated detection of flufenacet, identified in PDP 

data, at relatively high levels of 75 ppb in finished water at a water treatment facility in Indiana in 

2007. While this detection is higher in magnitude than the upper-bound EEC in surface water 

provided in this assessment (17.4 ppb, see Table 17); this flufenacet detection at 75 ppb is isolated 

and as such may be reflective of a distinctive set of circumstances such as a high-end runoff event 

which occurred in the area at the time of this detection. It is uncertain whether this value would 

represent a one-in-ten year peak concentration given the relatively small temporal scope of the 
Page 57 of 118 

monitoring data available for flufenacet. However, this detection in Indiana provides further 

evidence of flufenacet surface water exposure in an area where it is highly used. 

 Terrestrial Exposure 

Toxic response is a function of duration and intensity of exposure. For many compounds a gavage 

dose represents a very short-term high intensity exposure. Although the dose-based estimates may 

not reflect reality in that animals do not receive a gavage while feeding, it is possible that a shortduration, high-intensity exposure could occur associated with feeding on an agricultural field since 

many birds may gorge themselves when food items are available. While the dietary-based 

estimates may suggest greater “realism,” they too suffer from some uncertainties. Primarily, the 

dietary-based approach assumes that animals in the field are consuming food at a rate similar to 

that of confined laboratory animals despite the fact that energy content in food items differs 

between the field and the laboratory as does the energy requirements of wild and captive animals. 

Other uncertainties with flufenacet are related to the representativeness of T-REX with preemergent applications. Risks occurring indicated by T-REX due to flufenacet residues on seeds 

or arthropods located within treated fields are most certain with its pre-emergent applications. 

However, for risks related to broadleaf plants which may be a surrogate to crops, exposure may 

occur with the uptake of flufenacet residues in the soil as well as any residual residues that are 

remain in the plant system from the seed after germination. However, it should be noted that the 

extent to which flufenacet is systemic is unknown. While a rough indicator, flufenacet’s log Kow

of 3.2 suggests some ability for flufenacet to remain within the plant material for some period of 

time. 

Furthermore, additional risks with non-crop broadleaf plants as well as with short grass and long 

grass containing flufenacet residues are also possible with spray drift to areas containing grass 

offsite from the treated cultivated area. However, while T-REX would capture the upper-bound 

exposure in the treated field from these food items; the exact contribution due to spray drift is not 

explicitly quantified in T-REX. 

 Uncertainty in Risk Conclusions 

The EC25 and NOAEC values, however, only assess the effects on initial plant growth and survival. 

EPA current tests do not provide information on effects to reproduction, fruit formation or fruit 

yield. However, it is currently assumed that a 25 percent or greater effect on initial plant growth 

is indicative of subsequent reductions on plant populations, fruit formation and yield. In addition, 

the number of laboratory test species only account for eight of the 300 known plant families. The 

range of sensitivity of various plants to a phytotoxicant can be significantly higher than that 

exhibited in the laboratory because of intraspecies and interspecies variability, genetic differences 

in adaptability to environmental stresses, and magnitude and duration of exposure. 

6. Endocrine Disruptor Screening Program 
Page 58 of 118 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and 

sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic 

studies that assess growth, developmental and reproductive effects in different taxonomic groups. 

EPA has developed the EDSP to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a 

“naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” 

The EDSP employs a two-tiered approach to making the statutorily required determinations. Tier 

1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to 

interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go 

through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal 

systems will proceed to the next stage of the EDSP where EPA will determine which, if any, of 

the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any 

adverse endocrine-related effects caused by the substance, and establish a dose-response 

relationship between the dose and the E, A, or T effect. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals 

identified for EDSP screening was published on June 14, 20131

 and includes some pesticides 

scheduled for registration review and chemicals found in water. Neither of these lists should be 

construed as a list of known or likely endocrine disruptors. 

Flufenacet is not among the group of 58 pesticide active ingredients receiving EDSP test orders. 

For information on the status of the orders issued under the EDSP for each chemical, please visit 

our website at http://www.epa.gov/endo/ and click on the "Status of EDSP Orders/DCIs" in the 

Highlights Box. Additional information on the EDSP, including the policies and procedures, the 

list of 67 chemicals, the test guidelines and the Tier 1 screening battery, can also be found at this 

website. 

7. Federally Threatened and Endangered (Listed) Species of 

Concern 

At this current stage of the Registration Review process, it is premature to make effects 

determinations for listed species until further scientific analysis and refinements are conducted, 

based on recommendations received from the National Academy of Sciences’ (NAS) National 

Research Council (NRC) April 2013 report, available at 

 

1

 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals. 
Page 59 of 118 

http://www.nap.edu/catalog.php?record_id=18344. The NAS report outlines recommendations 

on specific scientific and technical issues related to the development of pesticide risk 

assessments that are compliant with the Endangered Species Act (ESA) and the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA). 

The EPA along with the U.S. Fish & Wildlife Service (USFWS), the National Marine Fisheries 

Service (NMFS) (collectively, the Services), and the U.S. Department of Agriculture (USDA), 

released a summary of their implementation plan for assessing risks of pesticides to listed species 

ahead of the stakeholder workshop held on November 15, 2013. This plan was developed in 

response to the NAS’ recommendations, including a common approach to risk assessment as a 

way of addressing scientific differences between EPA and the Services. During the workshop, the 

agencies received feedback from the public on the interim scientific approaches that were 

developed as part of the initial implementation of the NAS recommendations. These approaches 

will be jointly implemented and vetted as part of a phased iterative process. Once fully vetted, 

EPA will further refine the listed species effects determination portion of this risk assessment. 

To make effects determinations for individual listed species, useful refinements may include, but 

are not limited to, analyses of: 1) more detailed, species-specific ecological and biological data; 2) 

more detailed and accurate information on flufenacet use patterns; and 3) sub-county level spatial 

proximity data for the co-occurrence of potential effects areas and listed species and any designated 

critical habitat. Examples of such refinements are described below. 

EFED is currently developing tools that are expected to further refine the assessment and are 

designed to support effects determinations for individual federally listed species and their 

designated critical habitats (where applicable). Scientific information obtained from the 

Services, and other reliable sources is being collated by EFED to address all currently listed 

species. This information is being stored in an Office of Pesticide Programs (OPP) Pesticide 

Registration Information SysteM (PRISM) listed species knowledgebase. The listed species 

knowledgebase consists of an information repository that houses biological and behavioral 

information relevant to individual species (, habitat, diet, and life history, including specific 

temporal and spatial associations) and a document repository that contains supporting documents 

(e.g., USFWS recovery plans) and electronic information (, GIS data files). For terrestrial taxa, 

biological information relevant to the assessment (e.g., diet and body weight) will be used to 

parameterize exposure estimates using a method consistent with currently used methods in the TREX and T-HERPS models. 

Refinements will also include more detailed analyses of the registered uses and specific use 

patterns that result in either “Likely to Adversely Affect” (LAA) or “Not Likely to Adversely 

Affect” (NLAA) determinations for federally listed species. The analyses may include more 

information on where, when, and how pirimiphos-methyl is used on all use sites. Actual usage 

data (when available) and national land-cover datasets that indicate potential use sites [e.g., 

National Land Cover Dataset (NLCD), Cropland Data Layer (CDL)] may be used to support a 

more refined analysis of where flufenacet is reasonably expected to be used. Similarly, 

refinements on the timing of applications and a more in-depth exploration of agronomic practices 

for flufenacet may be included as part of the refinement. 
Page 60 of 118 

The refinements based on individual species data; additional, detailed usage information, when 

available; and recommendations from the NRC report are expected to help to more accurately 

identify potential areas of effect and to better inform effects and habitat determinations for listed 

species and any designated critical habitats. 

Conclusions 

After reviewing the most recent environmental fate and effects data for flufenacet, the screeninglevel assessment concludes that registered uses of the herbicide may result in risk to both listed 

and non-listed species of aquatic plants and terrestrial plants and animals. 

When estimates of flufenacet exposure in terrestrial and aquatic environments are compared to the 

available ecotoxicity data, the results of the screening-level assessment indicate a potential for risk 

to both aquatic plant taxa and terrestrial plant and animal taxa. There was not any risk identified 

for aquatic fish or invertebrates in either freshwater or estuarine environments. Because risk to 

water column invertebrates is low on both an acute and chronic basis when compared to both water 

column and porewater values and the low Koc of flufenacet indicates low partitioning to sediment 

particles, the risk to sediment dwelling organisms is presumed to be low as well. Risk above the 

level of concern was identified for aquatic plants (both vascular and non-vascular) at all application 

rates. For the majority of uses, the risk remained whether or not spray drift was eliminated in order 

to mitigate risk. 

Acute dose based risk to endangered birds was identified in all size classes of birds. Avian chronic 

RQs exceeded the LOC in for every scenario but wheat. Since the application of flufenacet occurs 

through both ground and aerial spray and residues can be transported to off-site food items there 

is likely to be both acute and chronic risk to birds. Acute risk to endangered mammals was only 

identified for the highest two application rates. Chronic risk however occurred at all application 

rates with RQs that were substantially higher than the level of concern for both dose-based and 

dietary based exposure. Therefore while acute risk to mammals exists there is higher risk on a 

chronic basis to mammals feeding on food items located around application sites. There was not 

any acute or chronic risk identified from the consumption of fish contaminated with flufenacet. 

The available data suggest that flufenacet is practically non-toxic to bees and preliminary modeling 

and RQ analysis suggests that risk to bees is low. As an herbicide, there is substantial risk to both 

listed and non-listed offsite plants exposed to flufenacet. For ground applications with the 

remaining corn, soybean, wheat, and grass seed uses, buffer distances range from 6 feet to 236 feet 

depending on application rate, droplet size and boom height. 

The overall risk conclusions for aquatic and terrestrial taxa broken down by each use of flufenacet 

are presented below in Table 30 and Table 31, respectively. 
Page 61 of 118 

Table 30. Summary of adverse impacts for aquatic organisms expected from the existing uses of flufenac

Proposed Use 

(App. Rate - 

lbs. a.i./A) 

Adverse Impacts Expected for Aquatic Organisms? (No/Yes: A = Acute, C=Chronic) 

Freshwater 

Fish 

Estuarine/

Marine 

Fish 

Estuarine/ 

Marine 

Invertebrates 

Freshwater and 

Saltwater 

Benthic 

Invertebrates 

(Sediment) 

Freshwater 

Benthic 

Invertebrates 

(Pore water) 

 Saltw

Bent

Inverteb

(Pore w

Freshwater Invertebrates 

(Water Column) (Water Column) 

Corn 

(Sweet and 

Field) 

(0.8019) 

No No No No No No No 

Soybean 

(0.4644) No No No No No No No 

Grass Seed 

(0.442) No No No No No No No 

Wheat & 

Triticale 

(0.3448) 

No No No No No No No 

*Risks identified applies for listed and non-listed aquatic plants for all uses. 
Page 62 of 118 

Table 31. Summary of adverse impacts for terrestrial organisms expected from the existiuses of flufenacet. 

Proposed Use 

(App. Rate - 

lbs. a.i./A) 

Adverse Impacts Expected for Terrestrial Organisms? (No/Yes: A = Acute, C=Chron

Birds Mammals Piscivorous Birds Piscivorous Mammals Terrestrial Plants Terrestr

Invertebr

Corn (Sweet and 

Field) 

(0.8019) 

YesA,C YesA,C No No Yes No 

Soybean 

(0.4644) YesA,C YesC No No Yes No 

Grass Seed 

(0.442) YesA,C YesC No No Yes No 

Wheat & Triticale 

(0.3448) YesA YesC No No Yes No 

*Risks identified applies for listed and non-listed terrestrial plants , and chronic risks to mammals and birds for all uses. Acute risks id

species for mammals and birds.
Page 63 of 118 

8. References 

CFR 40. 2007. Code of Federal Regulations 40 Parts 150 to 189. Protection of the 

Environment. U.S. Government Printing Office. 

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the 

EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on 

plants. Environ. Tox. Chem. 13:1383-1391. 

Hoerger, F. and E. E. Kenaga, 1972. Pesticide Residues on Plants: Correlation of Representative 

Data as a Basis for Estimation of their Magnitude in the Environment. In F. Coulston and 

F. Korte, eds., Environmental Quality and Safety: Chemistry, Toxicology, and 

Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9-28. 

Teske, M. E., & Curbishley, T. B. 2003. AGDISP Version 8.07 User Manual. Prepared For United 

States Department of Agriculture Forest Service. C.D.I. Technical Note No. 02-06. June 

2003. 

USEPA, 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of 

Research and Development, Washington, D.C. EPA/630/R-95/002F. April 1998. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759 

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, 2007a. Ecotoxicology (ECOTOX) database. Version 4. Office of Research and 

Development (ORD) , and the National Health and Environmental Effects Research 

Laboratory's (NHEERL's) Mid-Continent Ecology Division (MED). 

http://cfpub.epa.gov/ecotox/ecotox_home.cfm 

USEPA, 2007b. Ecological Incident Information System (EIIS). Environmental Fate and Effects 

Division. 

USEPA, 2009. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides. U.S. Environmental Protection Agency, Office of 

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

Environmental Fate and Effects Division. Nov. 10, 2009 Online at: 

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm. 

USEPA, 2010 Screening Level Estimates of Agricultural Uses on Flufenacet. Biological and 

Economic Assessment Division, Office of Pesticide Programs. Dated June 6, 2010. 
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USEPA, 2014[a]. Surface Water Concentration Calculator User Manual, Office of Prevention, 

Pesticides and Toxic Substances, Office of Pesticide Programs, Environmental Fate and 

Effects Division. July 1, 2014. 

USEPA, 2014[b]. Guidance for Assessing Pesticide Risks to Bees. USEPA Office of Pesticide 

Programs, Health Canada Pest Management Regulatory Agency, California Department of 

Pesticide Regulation. 

USEPA, 2014[c]. Guidance for Addressing Unextracted Residues in Laboratory Studies. 

USEPA Office of Pesticide Programs. 

U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS), 1998. 

Endangered Species Consultation Handbook: Procedures for Conducting Consultation 

and Conference Activities Under Section 7 of the Endangered Species Act. Final Draft. 

March 1998. 

USGS, 2010. National water quality assessment program. Accessed 2 November 2010. 

http://water.usgs.gov/nawqa/. 
Page 65 of 118 

Appendix A. Environmental Fate and Ecological Effects Data 

for Flufenacet 

PC Code 121903 Flufenacet Fate Chemistry Bibliography 

161-1 Hydrolysis 

MRID Citation Reference 

43441134 Zeng, Z.; Wood, S. (1992) Stability of FOE 5043 in Sterile Aqueous 

Buffer Solution: Lab Project Number: F3072401: 102623. Unpublished 

study prepared by Miles Environmental Research. 25 p. 

45796107 Shah, J.; Bloomberg, A. (1999) Hydrolysis Study of Thiadone (A 

Metabolite of FOE 5043): Lab Project Number: F3072402: 108719: 

7410-98-0058-EF-001. Unpublished study prepared by Bayer 

Corporation. 76 p. 

161-2 Photodegradation-water 

MRID Citation Reference 

43850003 Fontaine, L. (1995) Product Chemistry of FOE 5043 Technical: 

(Stability): Supplement to MRID 43441101: (Contains Data on 

Aqueous Photolysis of (carbon 14) Phenyl-U FOE 5043 and Photolysis 

of (carbon 14) Phenyl-U FOE 5043 on Sandy Loam): Lab Project 

Number: 106246: 106247: 107082. Unpublished study prepared by 

Bayer Corp. 157 p. 

43850056 Kasper, A.; Shadrick, B. (1995) Aqueous Photolysis of (carbon 14)-

Phenyl-U FOE 5043: Lab Project Number: F3082401: 106246: 92-B139. Unpublished study prepared by Bayer Corp. 79 p. 

161-3 Photodegradation-soil 

MRID Citation Reference 

43850003 Fontaine, L. (1995) Product Chemistry of FOE 5043 Technical: 

(Stability): Supplement to MRID 43441101: (Contains Data on 

Aqueous Photolysis of (carbon 14) Phenyl-U FOE 5043 and Photolysis 

of (carbon 14) Phenyl-U FOE 5043 on Sandy Loam): Lab Project 

Number: 106246: 106247: 107082. Unpublished study prepared by 

Bayer Corp. 157 p. 
Page 66 of 118 

43850057 Kasper, A.; Shadrick, B. (1995) Photolysis of (carbon 14)-U FOE 5043 

on Sandy Loam: Lab Project Number: 106247: F3082101: F3082102. 

Unpublished study prepared by Bayer Corp. 68 p. 

45796108 Lentz, N.; Bloomberg, A. (2001) Soil Photolysis of Thiadone on Loamy 

Sand (A Metabolite of FOE 5043): Lab Project Number: F3082103: 

108721: 7410-98-0055-EF-001. Unpublished study prepared by 

Ricerca LLC. 54 p. 

162-1 Aerobic soil metabolism 

MRID Citation Reference 

43441135 Pangilinan, N.; Smith, D. (1994) Aerobic Soil Metabolism of 

(Thiadiazole-2-(carbon 14))FOE 5043: Lab Project Number: 

F3042103: 106420. Unpublished study prepared by Miles Agriculture 

Division. 69 p. 

43441141 Pangilinan, N.; Smith, D. (1994) Aerobic Soil Metabolism of (Phenyl-U-

(carbon 14))FOE 5043: Lab Project Number: F3042102: 106408. 

Unpublished study prepared by Miles Agriculture Division. 89 p. 

43850058 Kelley, I.; Wood, S.; McKinney, M. (1995) Degradation of (carbon 14)-

U FOE 5043 in Three Soil Types: Lab Project Number: 106664: 92-B153: F3042104. Unpublished study prepared by Bayer Corp. 83 p. 

43850066 Shadrick, S.; Kasper, A. (1995) Outdoor Soil Metabolism of (carbon 

14)-Thiafluamide (FOE 5043) on California Soils: Lab Project Number: 

92183: 106210. Unpublished study prepared by Bayer Corp. and PanAgricultural Labs, Inc. 82 p. 

45796109 Lentz, N.; Bloomberg, A. (1999) Rate of Aerobic Soil Degradation for 

Thiadone (A Metabolite of FOE 5043): Amended Report: Lab Project 

Number: 7410-98-0008-EF-001-001: F3042108: 108722. Unpublished 

study prepared by Ricerca Inc. 125 p. 

162-2 Anaerobic soil metabolism 

MRID Citation Reference 

43850059 Pangilinan, N.; Smith, D. (1995) Anaerobic Soil Metabolism of (carbon 

14)-U FOE 5043: Lab Project Number: 106645: F3042106: 94-B-225. 

Unpublished study prepared by Bayer Corp. 108 p. 

162-3 Anaerobic aquatic metabolism 

MRID Citation Reference 

43850060 Pangilinan, N.; Smith, D. (1994) Anaerobic Aquatic Metabolism of 
Page 67 of 118 

(carbon 14)-U FOE 5043: Lab Project Number: F3042402: 106439: 

92-B-93. Unpublished study prepared by Bayer Corp. 89 p. 

43850061 Pangilinan, N.; Smith, D. (1995) Anaerobic Aquatic Metabolism of 

(carbon 14)-Thiadiazole-2 FOE 5043: Lab Project Number: 106440: 

F3042403. Unpublished study prepared by Bayer Corp. 76 p. 

45796110 Archer, G.; Korsch, B. (2001) Anaerobic Aquatic Metabolism of 

(Carbon-14) Thiadone, a Metabolite of FOE5043: Amended Report: 

Lab Project Number: 7410-98-0038-EF-001-001: F3042408. 

Unpublished study prepared by Ricerca LLC. 54 p. 

162-4 Aerobic aquatic metabolism 

MRID Citation Reference 

44580203 Kelley, I.; Wood, S.; McKinney, M. (1995) Degradability and Fate of 

(Phenyl-UL-(carbon 14))Foe 5043 in Two Sediment/Water Systems: 

Lab Project Number: F3042405: 106928. Unpublished study prepared 

by Bayer Corporation. 83 p. 

45796111 Archer, G.; Korsch, B. (2001) Aerobic Aquatic Soil Metabolism of 

(Carbon-14) Thiadone, a Metabolite of FOE5043: Lab Project Number: 

7410-98-0039-EF-001: F3042407: 108723. Unpublished study 

prepared by Ricerca LLC. 55 p. 

45796112 Halarnkar, P.; Irwin, D. (1997) Aerobic Aquatic Metabolism of 

(Thiadiazole-2-(Carbon-14)) FOE 5043 in Two Water/Sediment 

Systems: Lab Project Number: F3042406: 107822. Unpublished study 

prepared by Bayer Corporation. 55 p. 

163-1 Leach/adsorption/desorption 

MRID Citation Reference 

43441136 Kelley, I.; Wood, S. (1994) Leaching of Aged FOE 5043 Residues 

through Soil Columns: Lab Project Number: F3092101: 105014. 

Unpublished study prepared by Miles Research and Development 

Dept. 84 p. 

43441137 Kelley, I.; Wood, S. (1992) Adsorption/Desorption of FOE 5043 to Soil: 

Lab Project Number: F3182101: 103903. Unpublished study prepared 

by Miles Research and Development Dept. 46 p. 

43441138 Kelley, I.; Wood, S. (1993) Addendum to Miles Report No. 103903: 

Adsorption/Desorption of FOE 5043 to Soil: Lab Project Number: 

103903/1. Unpublished study prepared by Miles Research and 

Development Dept. 12 p. 

43441140 Blumhorst, M.; Yen, P.; Marlow, V. (1994) Soil Adsorption/Desorption 

of FOE 5043 Degradates: FOE Sulfonic Acid, FOE Methyl Sulfoxide, 

FOE Oxalate, FOE Alcohol, and Thiadone: Lab Project Number: 
Page 68 of 118 

F3182102: 122S19: 106598. Unpublished study prepared by EPL BioAnalytical Services, Inc. 122 p. 

163-2 Volatility - lab 

MRID Citation Reference 

45796113 Korsch, B.; Malekani, K. (2000) Laboratory Volatilization of (Carbon14) Thiadone from Soil: Lab Project Number: 7410-98-0168-EF-001: 

F3152101: 108725. Unpublished study prepared by Ricerca, LLC. 53 

p. 

164-1 Terrestrial field dissipation 

MRID Citation Reference 

43850062 Wood, S.; Lam, C.; Leimkuehler, W. (1995) Terrestrial Field 

Dissipation of FOE 5043 in North Carolina Soil, 1993: Lab Project 

Number: 106641: F3022101: ETI-2007MZ01. Unpublished study 

prepared by Bayer Corp.; Environmental Technologies Institute, Inc.; 

and Alta Analytical Labs. 185 p. 

43850063 Wood, S.; Lam, C.; Leimkuehler, W. (1995) Terrestrial Field 

Dissipation of FOE 5043 in Wisconsin Soil, 1993: Lab Project Number: 

CR9312: F3022103: 106643. Unpublished study prepared by Bayer 

Corp.; Agstat; and Alta Analytical Lab, Inc. 173 p. 

43850064 Leimkuehler, W.; Moore, K. (1994) Analytical Method for the 

Determination of FOE 5043 and Six Metabolites in Soil: Lab Project 

Number: F3112101: 106917. Unpublished study prepared by Miles, 

Inc. 53 p. 

43850065 Leimkuehler, W.; Moore, K. (1994) Supplemental to the Analytical 

Method for the Determination of FOE 5043 and Six Metabolites in Soil: 

Lab Project Number: F3112101: 106917-1. Unpublished study 

prepared by Miles, Inc. 19 p. 

43850066 Shadrick, S.; Kasper, A. (1995) Outdoor Soil Metabolism of (carbon 

14)-Thiafluamide (FOE 5043) on California Soils: Lab Project Number: 

92183: 106210. Unpublished study prepared by Bayer Corp. and PanAgricultural Labs, Inc. 82 p. 

165-1 Confined rotational crop 

MRID Citation Reference 
Page 69 of 118 

43441133 Lenz, M.; McKinney, M. (1994) Accumulation of (Phenyl-(carbon 14)) 

FOE 5043 Residues in Confined Rotational Crops: Lab Project 

Number: F3051601: 106768. Unpublished study prepared by Miles 

Research and Development Dept. 87 p. 

43850069 Halarnkar, P.; Mennicke, E. (1995) Accumulation of (Thiadiazole-2-

(carbon 14)) FOE 5043 Residues in Confined Rotational Crops: Lab 

Project Number: F3051602: 106639. Unpublished study prepared by 

Bayer Corp. 54 p. 

165-2 Field rotational crop 

MRID Citation Reference 

44253101 Krolski, M. (1997) Replies to Comments and Questions from the EPA 

Concerning the Metabolism of and the Analytical Methodology Used 

for FOE 5043: Lab Project Number: 107737. Unpublished study 

prepared by Bayer Corp. 22 p. 

44253103 Krolski, M. (1997) FOE 5043 60 DF--Magnitude of the Residue in Field 

Rotational Crops: (Final Report): Lab Project Number: 107703: 

F319RC01: BMS-F3028-94R. Unpublished study prepared by Bayer 

Corp. 1123 p. 

165-4 Bioaccumulation in fish 

MRID Citation Reference 

43441127 Gagliano, G. (1994) Uptake, Depuration and Bioconcentration of 

(carbon 14)-FOE 5043 Technical by Bluegill (Lepomis macrochirus) 

under Flow-Through Conditions: Lab Project Number: F3030301: 

106760. Unpublished study prepared by Miles Environmental 

Research Section. 41 p. 

43441139 Leimkuehler, W.; Moore, K. (1994) Identification of Radioactive 

Residues of Phenyl-(carbon 14)FOE 5043 in Bluegill Sunfish (Lepomis 

macrochirus): Lab Project Number: F3040301: 106577. Unpublished 

study prepared by Miles Research and Development Dept. 59 p. 

166-1 Ground water-small prospective 

MRID Citation Reference 

45737901 Dyer, D. (2002) Progress Report--July, 2002 FOE 5043 (AXIOM)--

Small-Scale Prospective Ground-Water Monitoring Study, Corn in 

Nebraska, 1995: Lab Project Number: F3212402: 200257. 

Unpublished study prepared by Bayer Corp. 211 p. 
Page 70 of 118 

45907901 Dyer, D.; Wood, S.; Helfrich, K. (2001) FOE 5043 (Flufenacet)--SmallScale Prospective Ground-Water Monitoring Study, Janesville, Iowa, 

1995: Lab Project Number: F3212401: 94401: 1396. Unpublished 

study prepared by Bayer Corporation and Stone Environmental, Inc. 

425 p. 

46997402 Dyer, D.; Helfrich, K. (2005) Flufenacet (FOE 5043) -- Small-Scale 

Prospective Ground-Water Monitoring Study, Minden, Nebraska, 1995. 

Project Number: F3212402, 004/03548/00, 1397. Unpublished study 

prepared by Bayer Corp., LFR Levine-Fricke, Inc. and Alta Analytical 

Laboratories. 542 p. 

835.6100 Terrestrial field dissipation 

MRID Citation Reference 

48897601 Leimkuehler, W.; Bethem, R.; Peterson, R. (1995) Determination of 

FOE 5043 and Four Metabolites in Soil by High Performance Liquid 

Chromatography Electrospray Tandem Mass Spectrometry (LCESI/MS/MS). Project Number: 106964. Unpublished study prepared 

by Alta Analytical Laboratories. 20p. 

48897602 Bruns, G.; Hoshowski, J. (1998) Independent Laboratory Validation of 

Analytical Method AMFOE2 for the Analysis of Soil for FOE 5043 and 

Four Metabolite Residues. Project Number: F3112106, 98BA04/REP, 

108145/MO/99/013955. Unpublished study prepared by Enviro-Test 

Laboratories (ETL). 90p. 

835.6200 Aquatic field dissipation 

MRID Citation Reference 

48897603 Bethem, R.; Peterson, R.; Leimkuehler, W. et al. (1995) Determination 

of FOE 5043 and the Alcohol, Oxalate, Thiadone and Sulfonic Acid 

Metabolites in Groundwater by High Performance Liquid 

Chromatography Electrospray Tandem Mass Spectrometry (LCESI/MS/MS). Project Number: AMFOE3 107138. Unpublished study 

prepared by Alta Analytical Laboratories. 22p. 

48897604 Bruns, G.; Hoshowski, J. (1998) Independent Laboratory Validation of 

Analytical Method AMFOE3 for the Analysis of Groundwater for FOE 

5043 and Four Metabolite Residues. Project Number: 98BAY05/REP, 

F3112402, 108265. Unpublished study prepared by Enviro-Test 

Laboratories (ETL). 85p. 

Non Guideline Selections 

44580202 Yen, P.; Kasper, A.; Pangilinan, N. (1997) Fate of FOE 5043 in the 

Environment (Updated Summary,1997): Lab Project Number: 107720. 
Page 71 of 118 

Unpublished study prepared by Bayer Corporation. 84 p. 

45796105 MacGregor, J.; Nixon, W. (1998) Analytical Method Verification for the 

Determination of the Thiadone Metabolite of FOE 5043 in Saltwater: 

Lab Project Number: 149C-105: 108335. Unpublished study prepared 

by Wildlife International Ltd. 32 p. 

In conjunction with Estuarine Toxicity Studies? 

43850068 Lin, H., D.L. Green, and P.S. Fig (1995) Freezer storage stability of 

[phenyl UL-14C] FOE 5043 in soil. Project # F3132101. Unpublished 

study performed and submitted by Miles, Inc., Kansas City, MO. 

43850067 Lin, H., D.L. Green, and P.S. Fig (1995) Freezer storage stability of 

seven metabolites 14C FOE 5043 in soil. Project # F3132102. 

Unpublished study performed and submitted by Miles, Inc., Kansas 

City, MO. 

D201249 Memo on Metabolite determination 

PC Code 121903 Flufenacet Eco Effects Bibliography

71-1 Avian Single Dose Oral Toxicity 

MRID Citation Reference 

43441113 Stafford, T. R. (1992) FOE 5043 Technical: An Acute Oral LD50 With 

Bobwhite Quail (Colinus virginianus) ID No. 106583. Laboratory: Miles 

Incorporated Agriculture Division. Research and Development 

Department, Environmental Research, Stilwell, Kansas. Sponsor: 

Miles Incorporated Agricultural Division, Kansas City, MO. 

44246801 Downs, K.; Hancock, G. (1997) FOE 5043 Technical: An Acute Oral 

LD50 with Mallards: (Final Report): Lab Project Number: 107700: 

F3710801. Unpublished study prepared by Bayer Corp. 32 p. 

71-2 Avian Dietary Toxicity 

MRID Citation Reference 

43441114 Toll, P. (1994) FOE 5043 Technical: A Subacute Dietary LC50 with 

Northern Bobwhite: Lab Project Number: F3721701: 106583. 

Unpublished study prepared by Miles Environmental Research 

Section. 48 p. 

43441115 Stafford, T. (1993) FOE 5043 Technical: A Subacute Dietary LC50 
Page 72 of 118 

with Mallard Duck: Lab Project Number: F3720801: 103814. 

Unpublished study prepared by Miles Environmental Research 

Section. 37 p. 

71-3 Wild mammal toxicity 

MRID Citation Reference 

44476901 Fairbrother, A.; Hancock, G. (1998) Dietary Toxicity (LC50) of FOE 

5043 with Deer Mice (Peromyscus maniculatus): Lab Project Number: 

BFOE5043DM-1-97: F3733901: 107826. Unpublished study prepared 

by Ecological Planning and Toxicology, Inc. 97 p. 

71-4 Avian Reproduction 

MRID Citation Reference 

43441119 Schmuck, R. (1994) Effects of a Subchronic Dietary Exposure of FOE 

5043 Tech. on Bobwhite Quail Including Effects on Reproduction and 

Health: Laboratory: Bayer AG Crop Protection 

Research Center Monheim, Institute for Environmental Biology 

D-51368 Leverkusen. Lab Project Number: F3741701: 106764. 

Unpublished study prepared by Bayer AG Institute for Environmental 

Biology. 162 p. 

43441120 Hancock, G.; Reynolds, M. (1994) Effect of Technical FOE 5043 on 

Mallard Reproduction: Lab Project Number: F3740801: 106594. 

Unpublished study prepared by Miles Environmental Research. 121 p. 

43441120 G.A. Hancock & M.L. Reynolds (1993) Effect of Technical FOE 5043 

on Mallard Reproduction. Laboratory: Bayer Corporation (formerly 

Miles, Inc.) Agricultural Division Research and Development 

Department 

Environmental Research, Stilwell, Kansas, Sponsor: Bayer 

Corporation 

Agricultural Division, Kansas City, Missouri. Laboratory Report ID: 

106594 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 
Page 73 of 118 

43441116 Gagliano, G.; Roney, D. (1994) Acute Toxicity of FOE 5043 Technical 

to the Bluegill (Lepomis macrochirus) under Flow-through Conditions: 

Lab Project Number: F3810301: 106558. Unpublished study prepared 

by Miles Environmental Research Section. 36 p. 

43441117 Gagliano, G.; Bowers, L. (1994) Acute Toxicity of FOE 5043 Technical 

to the Rainbow Trout (Oncorhynchus mykiss) under Flow-through 

Conditions: Lab Project Number: F3812201: 106572. Unpublished 

study prepared by Miles Environmental Research Section. 36 p. 

43595501 Bowers, L. (1995) Acute Toxicity of FOE 5043 Technical to the Bluegill 

(Lepomis macrochirus) Under Static-Renewal Conditions: Lab Project 

Number: 106674: F3810302. Unpublished study prepared by Miles, 

Inc. 31 p. 

43850007 Bowers, L.; Frank, J. (1995) Acute Toxicity of FOE 5043 Technical to 

the Rainbow Trout (Oncorhynchus mykiss) Under Static-Renewal 

Conditions: Lab Project Number: F3812202: 106673. Unpublished 

study prepared by Miles Inc. Agricultural Division. 31 p. 

45796101 Hall, A.; Lam, C. (1999) Acute Toxicity of Thiadone, a Metabolite of 

FOE 5043, to the Bluegill (Lepomis macrochirus): Lab Project Number: 

F3810901: 108455. Unpublished study prepared by Bayer 

Corporation. 33 p. 

45796102 Bowers, L.; Lam, C. (1998) Acute Toxicity of Thiadone to the Rainbow 

Trout (Oncorhynchus mykiss) Under Static Conditions: Lab Project 

Number: 108738: F3812203. Unpublished study prepared by Bayer 

Corporation. 33 p. 

72-2 Acute Toxicity to Freshwater Invertebrates 

MRID Citation Reference 

43441118 Bowers, L. (1994) Acute Toxicity of FOE 5043 Technical to the 

Waterflea (Daphnia magna) under Static Conditions: Lab Project 

Number: F3820701: 106579. Unpublished study prepared by Miles 

Environmental Research Section. 27 p. 

43595503 Bowers, L. (1995) Acute Toxicity of FOE 5043 Technical to the 

Hyalella azteca Under Flow-Through Conditions: Lab Project Number: 

106908: F3823201. Unpublished study prepared by Miles, Inc. 33 p. 

45796103 Bowers, L.; Lam, C. (1998) Acute Toxicity of Thiadone (a Metabolite of 

FOE 5043) to the Waterflea Daphnia magna Under Static Conditions: 

Lab Project Number: F3820702: 108464. Unpublished study prepared 

by Bayer Corporation. 32 p. 

72-3 Acute Toxicity to Estuarine/Marine Organisms 

MRID Citation Reference 
Page 74 of 118 

43441121 Wheat, J. (1993) Acute Toxicity of FOE 5043 (Technical) to the Mysid 

(Mysidopsis bahia): Lab Project Number: J9208007B: 105180: 

F3832001. Unpublished study prepared by Toxikon Environmental 

Sciences. 50 p. 

43441122 Gagliano, G.; Bowers, L. (1994) Acute Toxicity of FOE 5043 to the 

Sheepshead Minnow (Cyprinodon variegatus) under Static Renewal 

Conditions: Lab Project Number: F3832801: 106421. Unpublished 

study prepared by Miles Environmental Research Section. 31 p. 

43441123 Wheat, J.; Evans, J. (1993) Acute Effect of FOE 5043 (Technical) on 

New Shell Growth of the Eastern Oyster (Crassostrea virginica): Lab 

Project Number: J9201017B: 105181: F3821501. Unpublished study 

prepared by Toxikon Environmental Sciences. 49 p. 

45796104 Bowers, L.; Lam, C. (1999) Acute Toxicity of Thiadone to the 

Sheepshead Minnow (Cyprinodon variegatus) Under Static Conditions: 

Lab Project Number: F3832802: 108809. Unpublished study prepared 

by Bayer Corporation. 32 p. 

45796106 Palmer, S.; Krueger, H. (1998) Thiadone Metabolite of FOE 5043: A 

96 Hour Flow-Through Acute Toxicity Test with the Saltwater Mysid 

(Mysidopsis bahia): Lab Project Number: 149A-113: 108488. 

Unpublished study prepared by Wildlife International Ltd. 46 p. 

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study 

MRID Citation Reference 

43441124 Wheat, J. (1994) FOE 5043 Technical: Chronic Toxicity to the Mysid, 

Mysidopsis bahia, under Flow-Through Test Conditions: Lab Project 

Number: J9310003: 106574. Unpublished study prepared by Toxikon 

Environmental Sciences. 68 p. 

43441125 Gagliano, G. (1994) Early Life Stage Toxicity of FOE 5043 Technical 

to the Rainbow Trout (Oncorhynchus mykiss) under Flow-Through 

Conditions: Lab Project Number: F3842201: 106761. Unpublished 

study prepared by Miles Environmental Research Section. 73 p. 

43441126 Gagliano, G.; Bowers, L. (1994) Chronic Toxicity of FOE 5043 

Technical to the Waterflea (Daphnia magna) under Static Renewal 

Conditions: Lab Project Number: F3840701: 106762. Unpublished 

study prepared by Miles Environmental Research Section. 65 p. 

43595502 Davis, J. (1995) Chronic Toxicity of FOE 5043 Technical to the Mysid 

Shrimp (Mysidopsis bahia) Under Flow-Through Conditions: Lab 

Project Number: 106675: J9405004. Unpublished study prepared by 

Toxikon Environmental Sciences. 70 p. 

43795301 Gagliano, G. (1995) Early Life Stage Toxicity of FOE 5043 Technical 

to the Rainbow Trout (Oncorhynchus mykiss) Under Flow-Through 

Conditions: Lab Project Number: 106978: F3842202. Unpublished 

study prepared by Bayer Corp. 82 p. 
Page 75 of 118 

45796114 Palmer, S.; Krueger, H. (1998) Thiadone Metabolite of FOE 5043: A 

96 Hour Flow-Through Acute Toxicity Test with the Saltwater Mysid 

(Mysidopsis bahia): Lab Project Number: 149A-113: 108488. 

Unpublished study prepared by Wildlife International Ltd. 46 p. 

72-5 Fish Full Lifecycle Test 

45796114 Hall, A.; Lam, C. (2002) Fathead Minnow (Pimephales promelas) Fish 

Life Cycle Test with Flufenacet (FOE 5043 Technical): Lab Project 

Number: F3851201: 109767. Unpublished study prepared by Bayer 

Corporation. 262 p. 

72-6 Aquatic org. accumulation 

MRID Citation Reference 

43441127 Gagliano, G. (1994) Uptake, Depuration and Bioconcentration of 

(carbon 14)-FOE 5043 Technical by Bluegill (Lepomis macrochirus) 

under Flow-Through Conditions: Lab Project Number: F3030301: 

106760. Unpublished study prepared by Miles Environmental 

Research Section. 41 p. 

123-1 Seed germination/seedling emergence and vegitative vigor 

MRID Citation Reference 

43465002 Johns, C. (1994) Tier 2 Seed Germination, Seedling Emergence, and 

Vegetative Vigor Nontarget Phytotoxicity Study Using FOE 5043: Lab 

Project Number: 106780: F3201601. Unpublished study prepared by 

Miles, Inc. 188 p. 

123-2 Aquatic plant growth 

MRID Citation Reference 

43441128 Gagliano, G. (1994) Acute Toxicity of FOE 5043 Technical to the 

Green Alga (Selenastrum capricornutum): Lab Project Number: 

F3881401: 106763. Unpublished study prepared by Miles 

Environmental Research Section. 36 p. 

43441129 Gagliano, G. (1994) Acute Toxicity of FOE 5043 Technical to the 

Diatom (Navicula pelliculosa): Lab Project Number: F3881603: 

106756. Unpublished study prepared by Miles Environmental 

Research Section. 34 p. 

43441130 Gagliano, G. (1994) Acute Toxicity of FOE 5043 Technical to the 
Page 76 of 118 

Marine Diatom (Skeletonema costatum): Lab Project Number: 

F3881402: 106751. Unpublished study prepared by Miles 

Environmental Research Section. 35 p. 

43441131 Hughes, J.; Alexander, M. (1993) Acute Toxicity of FOE 5043 

(Technical) to Anabaena flos-aquae: Lab Project Number: B059/022/1: 

105199. Unpublished study prepared by Malcolm Pirnie Inc. 43 p. 

43441132 Hughes, J.; Alexander, M. (1993) Acute Toxicity of FOE 5043 

(Technical) to Lemna gibba G3: Lab Project Number: B059/022/2: 

105198. Unpublished study prepared by Malcolm Pirnie Inc. 42 p. 

43834401 Bowers, L.; Dobbs, M. (1995) Acute Toxicity of (carbon 14)-FOE 5043 

Technical to the Freshwater Diatom (Navicula pelliculosa): Lab Project 

Number: 107113: F3883401. Unpublished study prepared by Bayer 

Corp. 34 p. 

43834402 Bowers, L. (1995) Acute Toxicity of (carbon 14)-FOE 5043 Technical 

to the Green Alga Selenastrum capricornutum: Lab Project Number: 

107114: F3883501. Unpublished study prepared by Bayer Corp. 33 p. 

43834403 Bowers, L. (1995) Acute Toxicity of (carbon 14)-FOE 5043 Technical 

to the Marine Diatom Skeletonema costatum: Lab Project Number: 

107115: F3883601. Unpublished study prepared by Bayer Corp. 34 p. 

43834403 Bowers, L. (1995) Acute Toxicity of (carbon 14)-FOE 5043 Technical 

to the Marine Diatom Skeletonema costatum: Lab Project Number: 

107115: F3883601. Unpublished study prepared by Bayer Corp. 34 p. 

43850050 Dobbs, M. (1995) Data Analysis Correction for the Acute Toxicity of 

FOE 5043 Technical to the Diatom (Navicula pelliculosa): Amended 

Report: Lab Project Number: F3881603: 106756-1. Unpublished study 

prepared by Bayer Corp. 20 p. 

43850051 Dobbs, M. (1995) Data Analysis Correction for the Acute Toxicity of 

FOE 5043 Technical to the Marine Diatom (Skeletonema costatum): 

Amended Report: Lab Project Number: F3881402: 106751-1. 

Unpublished study prepared by Bayer Corp. 20 p. 

43850052 Dobbs, M. (1995) Data Analysis Correction for the Acute Toxicity of 

FOE 5043 Technical to the Green Alga (Selenastrum capricornutum): 

Amended Report: Lab Project Number: F3881401: 106763-1. 

Unpublished study prepared by Bayer Corp. 22 p. 

45796115 Hall, A.; Lam, C. (1999) Toxicity of (Carbon-14)-Thiadone, a 

Metabolite of FOE 5043, to the Green Alga, Selenastrum 

capricornutum: Lab Project Number: F3883502: 108823. Unpublished 

study prepared by Bayer Corporation. 33 p. 

141-1 Honey bee acute contact 

MRID Citation Reference 

43465001 Mayer, D. (1994) FOE 5043/Honey Bees Acute Toxicity: Lab Project 

Number: 94-002: 106765: F3772901. Unpublished study prepared by 

Washington State University. 21 p. 
Page 77 of 118 

44112201 Mayer, D. (1996) FOE 5043/Honey Bees Acute Toxicity: (Final 

Report): Lab Project Number: F3712901: 107517: WSU 96-001. 

Unpublished study prepared by Washington State University. 23 p. 

850.1035 Mysid acute toxicity test 

MRID Citation Reference 

49119001 Claude, M.; Martin, K.; Gallagher, S.; et al. (2013) Flufenacet: A 96-

Hour Static Acute Toxicity Test with the Saltwater Mysid (Americamysis 

bahia). Project Number: EBFOL242, 149A/248 M/452205/01/1. 

Unpublished study prepared by Wildlife International, Ltd. 58p. 

850.1350 Mysid chronic toxicity test 

MRID Citation Reference 

49119002 Claude, M.; Martin, K.; Gallagher, S.; et al. (2013) Flufenacet: A Flowthrough Life-Cycle Toxicity Test with the Saltwater Mysid (Americamysis 

bahia). Project Number: 149A/246, EBFOL243, M/452207/01/1. 

Unpublished study prepared by Wildlife International, Ltd. 121p. 

850.1400 Fish early-life stage toxicity test 

MRID Citation Reference 

4924420

1 

 Banman, C.; Alexander, T.; Moore, S. (2013) Early Life Stage Toxicity 

of Flufenacet Technical to the Sheepshead Minnow (Cyprinodon 

variegatus) Under Flow-Through Conditions. Project Number: 

EBFOL244, M/464909/01/1. Unpublished study prepared by SynTech 

Research Laboratory Services, LLC. 102p. Relates to L0001608. 

850.2100 Avian acute oral toxicity test 

MRID Citation Reference 

49244202 Christ, M. (2013) Toxicity of Flufenacet Technical During an Acute Oral 

LD50 with the Canary (Serinus canaria): Final Report. Project Number: 

07SRLS13C5, EBFOL245. Unpublished study prepared by SynTech 
Page 78 of 118 

Research Laboratory Services, LLC. 47p. Relates to L0001608. 

850.4225 Seedling emergence, Tier II 

MRID Citation Reference 

48897605 Friedrich, S. (2005) Flufenacet SC 500: Seedling Emergence and 

Seedling Growth Test on Terrestrial Non-target Plants: Final Report. 

Project Number: 04/10/48/104, MO/05/006018. Unpublished study 

prepared by Biochem Agrar, Labor fuer Biologische und Chemische. 

108p. 

48897606 Pallett, K.; Gosch, H. (2006) Flufenacet & Isoxaflutole WG 58: Effect 

on Ten Species of Non-target Terrestrial Plants: Seedling Emergence 

and Seedling Growth Test (Tier 2). Project Number: SE/05/041 

EBFOX1171. Unpublished study prepared by Bayer CropScience 

GmbH. 162p. 

48897607 Pallett, K.; Gosch, H. (2006) Flufenacet & Isoxaflutole SC 480 (AE 

F133402 01 SC40 A401): Effect on Ten Species of Non-target 

Terrestrial Plants: Seedling Emergence and Seedling Growth Test 

(Tier 2). Project Number: SE/05/059, EBFOX131. Unpublished study 

prepared by Bayer CropScience GmbH. 176p. 

48897608 Bowers, L. (2000) Tier 2 Seedling Emergence and Vegetative Vigor 

Nontarget Phytotoxicity Study Using Axiom 58 DF. Project Number: 

109592, AX451602, AX451601. Unpublished study prepared by Bayer 

CropScience. 99p 

850.4250 Vegetative vigor, Tier II 

MRID Citation Reference 

 

48897608 Bowers, L. (2000) Tier 2 Seedling Emergence and Vegetative Vigor 

Nontarget Phytotoxicity Study Using Axiom 58 DF. Project Number: 

109592, AX451602, AX451601. Unpublished study prepared by Bayer 

CropScience. 99p. 

48897609 Friedrich, S. (2005) Flufenacet SC 500: Vegetative Vigor Test on Nontarget Terrestrial Plants: Final Report. Project Number: 

04/10/48/105/MO/05/006019, 04/10/48/105. Unpublished study 

prepared by Biochem Agrar, Labor fuer Biologische und Chemische. 

93p. 

48897610 Pallett, K.; Gosch, H. (2006) Flufenacet & Isoxaflutole WG 58: Effects 

on Ten Species of Non-target Terrestrial Plants: Vegetative Vigor Test 

(Tier 2). Project Number: VV/05/042 EBFOX116. Unpublished study 

prepared by Bayer CropScience GmbH. 130p. 

48897611 Pallett, K.; Gosch, H. (2006) Flufenacet & Isoxaflutole SC 480 (AE 

F133402 01 SC40 A401): Effects on Ten Species of Non-target 

Terrestrial Plants: Vegetative Vigor Test (Tier 2). Project Number: 
Page 79 of 118 

VV/05/060, EBF0X132. Unpublished study prepared by Bayer 

CropScience GmbH. 131p. 

Non-Guideline Studies 

MRID Citation Reference 

 

43850006 Toll, P. (1995) Residues of FOE 5043 on Avian Forage and the 

Availability of Forage Plants in Corn Fields: Lab Project Number: 

F3762301: 42497: 107101. Unpublished study prepared by Bayer 

Corp. Agricultural Division. 56 p. 

43948801 Heimbach, F. (1995) Toxicity of FOE 5043 T (Tech.) to Earthworms: 

Lab Project Number: 107310: E 310 0870-9: HBF/RG 202. 

Unpublished study prepared by Bayer AG. 22 p. 

44246800 Bayer Corp. (1997) Submission of Hazard to Wildlife Data in Support 

of FIFRA 6(a)(2) for FOE 5043 (Thiafluamide). Transmittal of 1 Study. 

46400701 Bloomberg, A. (2004) Tier 3 Acute and Chronic Dietary Exposure Assessments for 

Flufenacet. Project Number: 201169. Unpublished study prepared by Bayer CropScience 

LP. 65 p. 

48648901 Blanck, M. (2011) Flufenacet (FOE5043) Comparative Thyroid Sensitivity Assay in the Rat 

by Dietary Exposure: (Gestational and Lactational Exposure Phase). Unpublished study 

prepared by Bayer CropScience. 16p. 

48648902 Blanck, M. (2011) Flufenacet (FOE5043) Comparative Thyroid Sensitivity Assay in the Rat: 

Complementary Assay: (Gavage Exposure Phase). Unpublished study prepared by Bayer 

CropScience. 12p. 

48898903 Blanck, M. (2012) Flufenacet (FOE5043) - Comparative Thyroid Sensitivity Assay in the Rat 

by Dietary Exposure (Gestational and Lactational Exposure Phase). Project Number: 

M/435313/01/1/OCR, SA/11052, LYNX/PSI/N/TXFOX035. Unpublished study prepared by 

Bayer CropScience. 1056p 

48898906 Gomez, C. (2011) Flufenacet - Determination by High Performance Liquid Chromatography 

Analysis in Ground Rodent Diet. Project Number: M/426082/01/2/OCR, SA/11357. 

Unpublished study prepared by Bayer CropScience. 20p. 

48898907 Tahmasseb, A. (2011) Flufenacet - Stability in Aqueous 0.5 Percent Methylcellulose 400. 

Project Number: M/418123/01/2/OCR, SA/11177. Unpublished study prepared by Bayer 

CropScience. 17p. 
Page 80 of 118 

Appendix B. Status of Environmental Fate and Ecological 

Effects Studies for Flufenacet 

Table B-1. Available environmental fate data and study classification for flufenacet and thiadone 

degradate. 

Chemical No: 121903 

FLUFENACET 

DATA REQUIREMENTS FOR THE 

ENVIRONMENTAL FATE AND EFFECTS DIVISION 

Data Requirements Composition1 Use 

Pattern2

Bibliographic 

Citation Study Classification 

158.290 ENVIRONMENTAL FATE 

Degradation Studies – Lab: 

161-1 Hydrolysis 

PAIRA 

Thiadone 

1 and 2 

1 and 2 

43441134 

45796107 

Acceptable 

Supplemental 

161-2 Photolysis in Water 

PAIRA 

Thiadone

1 and 2 43850056 

46997401 

Acceptable 

Acceptable 

 

161-3 Photolysis in Soil PAIRA 

Thiadone 

1 and 2 

1 and 2 

43850057 

45796108 

Acceptable 

Supplemental 

Metabolism Studies – Lab:

162-1 Aerobic Soil 

Metabolism 

PAIRA 

PAIRA 

PAIRA 

Thiadone 

1 and 2 

1 and 2 

1 and 2 

1 and 2 

43441141 

43441135 

43850058 

45796109 

Acceptable 

Acceptable 

Supplemental 

Supplemental 

162-2 Anaerobic Soil 

Metabolism 

PAIRA 

(degradate) 

1 and 2 43850059 Supplemental 

162-3 Anaerobic Aquatic 

Metabolism 

PAIRA 

PAIRA 

Thiadone 

1 and 2 

1 and 2 

1 and 2 

43850060 

43850061 

45796110 

Acceptable 

Acceptable 

Supplemental 

162-4 Aerobic Aquatic 

Metabolism 

PAIRA 

Thiadone 

1 and 2 

1 and 2 

45796112 

44580203 

45796111 

Acceptable 

Supplemental 

Acceptable 

Mobility Studies:

163-1 Adorption (unaged) PAIRA 

Thiadone 

1 and 2 

1 and 2 

43441137 

43441140 

Acceptable 

Acceptable 

163-1 Leaching (aged) PAIRA 1 and 2 43441136 Supplemental 

163-2 Laboratory volatility Thiadone 1 and 2 45796113 Supplemental 

163-3 Field Volatility PAIRA 1 and 2 None submitted 

Dissipation Studies - Field:

164-1 Terrestrial Field 

Dissipation 

ECM/ILV in soil 

TEP (DF) 

TEP (DF) 

1 and 2 

1 and 2 

43850062 

43850063 

43850064 

43850065 

Acceptable 

Acceptable 

Invalid 

Supplemental 

Accumulation Studies:

165-4 Fish 

Bioaccumulation 

PAIRA 1 and 2 43441127 

43441139 

Acceptable 

Ground Water Monitoring Studies:
Page 81 of 118 

Table B-1. Available environmental fate data and study classification for flufenacet and thiadone 

degradate. 

Chemical No: 121903 

FLUFENACET 

DATA REQUIREMENTS FOR THE 

ENVIRONMENTAL FATE AND EFFECTS DIVISION 

Data Requirements Composition1 Use 

Pattern2

Bibliographic 

Citation Study Classification 

166-1 Small Scale 

Prospective Groundwater 

Study 

ECM/ILV in water 

TEP (DF) 1 and 2 45907901 (in 

Iowa) 

46997402 (in 

Nebraska) 

45796105 

(seawater) 

Acceptable 

Acceptable 

Acceptable 

Notes: 

1. Composition: PAIRA=Pure active ingredient, radiolabeled; TEP=Typical end-use Product. 

2. Use Patterns: 1 = Terrestrial/Food; 2 = Terrestrial/Feed. 

TableB-2. Ecological effects data and study classifications for flufenacet . 

Guideline # Data Requirement Test Substance MRID # or 

Citation Study Classification 

850.2100 Avian Oral LD50 TGAI 

43441113 

44246801 

49244202 

44246801 

Acceptable 

Supplemental 

Acceptable 

Supplemental 

850.2200 Avian Dietary LC50

TGAI 

TGAI 

43441114 

43441115 

Acceptable 

Acceptable 

850.2300 Avian Reproduction TGAI 

TGAI 

43441119 

43441120 

Acceptable 

Acceptable 

850.1075 Freshwater Fish LC50

TGAI 

TGAI 

TGAI 

TGAI 

43441116 

43595501 

43441117 

43850007 

Acceptable 

Acceptable 

Acceptable 

Acceptable 

850.1010 

Freshwater 

Invertebrate Acute 

LC50

TGAI 

TGAI 

43441118 

43595503 

Supplemental 

Acceptable 

850.1075 Estuarine/Marine Fish 

LC50

TGAI 43441122 Acceptable 

850.1025 Estuarine/Marine 

Mollusk EC50

TGAI 43441123 Acceptable 

850.1035 

850.1045 

850.1055 

850.1075 

Estuarine/Marine 

Shrimp EC50

TGAI 43441121 

49119001 

Supplemental 

Acceptable 
Page 82 of 118 

TableB-2. Ecological effects data and study classifications for flufenacet . 

Guideline # Data Requirement Test Substance MRID # or 

Citation Study Classification 

850.1400 Freshwater Fish Early 

Life-Stage TGAI 43441125 

43795301 

Invalid 

Acceptable 

850.1400 Estuarine/Marine Fish 

Early Life-Stage TGAI 49244201 Acceptable 

850.1300 

Aquatic Invertebrate 

Life-Cycle 

(freshwater) 

TGAI 43441126 Acceptable 

850.1350 Aquatic Invertebrate 

Life-Cycle (marine) TGAI 

43595502 

43441124 

49119002 

Supplemental 

Supplemental 

Acceptable 

850.1500 Fish Full Life-Cycle TGAI 45796114 Supplemental 

850.4225 Seedling Emergence 

(Tier II) 61% 43465002 Acceptable 

850.4250 Vegetative Vigor 

(Tier II) 61% 43465002 Acceptable 

850.4400 

850.5400 

Aquatic Plant Growth 

 (Tier II) TGAI 

43441132 

43441128 

43850052 

43834402 

43441130 

43850051 

43834403 

43441129 

43850050 

43834401 

43441131 

45796115 

(thiadone) 

48897612 

(thiadone) 

Acceptable 

Invalid 

Acceptable 

Acceptable 

Invalid 

Acceptable 

Acceptable 

Invalid 

Acceptable 

Acceptable 

Acceptable 

Acceptable 

Supplemental 

Acceptable 

850.3020 Honey Bee Acute 

 Contact LD50

TGAI 

44112201 

43465001 

Acceptable 

Invalid 

850.3030 Honey Bee Residue 

on Foliage No data submitted NA 
Page 83 of 118 

TableB-2. Ecological effects data and study classifications for flufenacet . 

Guideline # Data Requirement Test Substance MRID # or 

Citation Study Classification 

870.1100 Acute Oral Toxicity 

to Rat 

TGAI 

TGAI + 

Metribuzin 

43441104 

43441105 

Acceptable 

Acceptable 

870.3100 Subchronic Mammal TGAI 

43743401 

43738101 

43619401 

Acceptable 

Acceptable 

Acceptable 

870.3700 

Prenatal 

Developmental 

Toxicity Study - Rat 

TGAI 43850030 Acceptable 

870.3800 Mammalian 

Reproduction -- Rat TGAI 3850033 Acceptable 

*NA means not applicable 

1

Thiadone is a major degradate of flufenacet, to which aquatic plants are likely to be exposed due to the 

persistence and mobility of thiadone. 
84 

Appendix C. Formation and Decline of Flufenacet Metabolit

Table C-1. Flufenacet transformation products

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Aerobic Soil Metabolism 

Transformation Product 1 Thiadone 5-(Trifluoromethyl)-1,3,4-thiadiazol-2(3H)-one or 5-Trifluoromethyl-1,3,4-thiadiazol-2(3H)-one or 3-Trifluoromethyl-1,3,4-thiadiazol-2(3H)one 

3.9% @ 7 d 0.9% @ 368 d 43441135 

162-1 

Thiadiaz

Anaerobic Aquatic Metabolism 16.0% @ 99 d 16.0% @ 99 d 43850061 

162-3 

Thiadiazsandy loa

Aerobic Aquatic Metabolism84.3% @ 55 d 68.7% @ 156 d 45796112 

162-4 

Thiadiazsilty clay system) 

63.8% @ 100 d 54.2% @ 156 d 45796112 

162-4 

Thiadiazsilty clay entire sys

Field Dissipation Studies Below LOD (<0.01 ppm) throughout study 

Below LOD (<0.01 ppm) @ 554 d 

43850062 164-1 

North Cainches) 

Below LOD (<0.01 ppm) throughout study 

Below LOD (<0.01 ppm) @ 466 d 

43850063 164-1 

Wisconsiinches) 
85 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Prospective Ground Water Study Below the LOQ (10 μg/kg) throughout the study 

Below the LOQ (10 μg/kg) at 489 d 

45907901 166-1 

Sandy lo

Transformation Product 2 Flufenacet methylsulfide 4-Fluoro-N-methylethylanaline methylthioacetamide 

Aerobic Aquatic Metabolism

11.4% @ 157 d 11.4% @ 157 d 44580203 

162-4 

Phenyl laloam sed

) 4.5% @ 157 d 4.5% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 
86 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 3 Flufenacet oxalate [(4-Fluorophenyl)(1-methylethyl)]amino]oxoacetic acid or [(4-Fluorophenyl)(1-methylethyl)]amino]2-oxoacetic acid 

Soil Photolysis 

irradiated- 0.6% @ 30 d dark- 4.6% @ 30 d 

irradiated- 0.6% @ 30 d dark- 4.6% @ 30 d 

43850057 161-3 

Phenyl la

Aerobic Soil Metabolism26.5% @ 365 d 26.5% @ 365 d 43441141 

162-1 

Phenyl la

6.6% @ 28 d Not detected @ 120 d 43850058 

162-1 

Phenyl la

15.6% @ 28 d Not detected @ 120 d 43850058 

162-1 

Phenyl la(Laacher

10.0% @ 28 d Not detected @ 120 d 43850058 

162-1 

Phenyl la

13.0% @ 46 d 11.7% @ 88 d 43850066 

162-1 

Phenyl la

7.6% @ 88 d 7.6% @ 88 d 43850066 

162-1 

Phenyl la

Anaerobic Soil Metabolism14.5% @ 60 d 9.9% @ 210 d 43850059 

162-2 

Phenyl la
87 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Aerobic Aquatic Metabolism4.6% @ 157 d 4.6% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

5.4% @ 157 d 5.4% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

Terrestrial Field Dissipation 0.1 ppm @ 5 and 369 d Below LOD (<0.01 ppm) 

@ 554 d 

43850062 164-1 

North Cainches) 

0.01 ppm @ 27 and 369 d Below LOD (<0.01 ppm) 

@ 466 d 

43850063 164-1 

Wisconsiinches) 
88 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 4 Flufenacet sulfonic acid 4-Fluoro-N-methylethylaniline-sulfoacetamide or N-Fluoro-N-methylethylaniline-sulfoacetamide or 2-[(4-Fluorophenyl)(1-methylethyl)amino]-oxoethylsulfonic acid 

Soil Photolysis 

irradiated- 0.4% @ 15 d dark- 2.2% @ 30 d 

irradiated- 0.3% @ 30 d dark- 2.2% @ 30 d 

43850057 161-3 

Phenyl la

Aerobic Soil Metabolism7.7% @ 180 d 5.3% @ 365 d 43441141 

162-1 

Phenyl la

25.4% @ 100 d 22.6% @ 120 d 43850058 

162-1 

Phenyl la

26.3% @ 100 d 21.8% @ 120 d 43850058 

162-1 

Phenyl la(Laacher

13.5% @ 100-120 d 13.5% @ 120 d 43850058 

162-1 

Phenyl la

2.4% @ 88 d 2.4% @ 88 d 43850066 

162-1 

Phenyl la

1.3% @ 88 d 1.3% @ 88 d 43850066 

162-1 

Phenyl la

Anaerobic Soil Metabolism 6.6% @ 30 d 4.5% @ 210 d 43850059 

162-2 

Phenyl la
89 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Aerobic Aquatic Metabolism 1.65% @ 157 1.65% @ 157 d 44580203 

162-4 

Phenyl laloam sedonly) 

3.2% @ 157 d 3.2% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

Terrestrial Field DissipationBelow LOD (<0.01 ppm) throughout study 

Not analyzed @ 554 d 43850062 

164-1 

North Cainches) 

0.02 ppm @ 14 to 27 d Below LOD (<0.01 ppm) 

@ 466 d 

43850063 164-1 

Wisconsiinches) 

Prospective Ground Water Below the LOQ (10 μg/kg) throughout the study 

Below the LOQ (10 μg/kg) at 489 d 

45907901 166-1 

Sandy lo

Transformation Product 5 Flufenacet methylsulfoxide 4-Fluoro-N-methylethylanaline methylsulfenylacetamide 

Soil Photolysis 

irradiated- 0.7% @ 30 d dark- 0.6% @ 30 d 

irradiated- 0.7% @ 30 d dark- 0.6% @ 30 d 

43850057 161-3 

Phenyl la

Aerobic Soil Metabolism0.6% @ 28 d Not detected @ 365 d 43441141 

162-1 

Phenyl la
90 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

1.1% @ 28-56 d Not detected @ 120 d 43850058 

162-1 

Phenyl la

3.5% @ 56 d 0.7% @ 120 d 43850058 

162-1 

Phenyl la(Laacher

1.5% @ 56 d 0.2% @ 120 d 43850058 

162-1 

Phenyl la

1.3% @ 88 d 1.3% @ 88 d 43850066 

162-1 

Phenyl la

0.9% @ 88 d 0.9% @ 88 d 43850066 

162-1 

Phenyl la

Aerobic Aquatic Metabolism 3.2% @ 157 d 3.2% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

2.2% @ 120 d 1.7% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 
91 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 6 Flufenacet methylsulfone N-(fluorophenyl)-N-(1-methylethyl)-2-(methylsulfonyl)acetamide or 4-Fluoro-N-methylethylaniline methylsulfonylacetamide 

Aerobic Soil Metabolism

6.6% @ 100 d 4.7% @ 120 d 43850058 

162-1 

Phenyl la

4.3% @ 120 d 4.3% @ 120 d 43850058 

162-1 

Phenyl la(Laacher

5.6% @ 120 d 5.6% @ 120 d 43850058 

162-1 

Phenyl la

0.5% @ 46 d 0.3% @ 88 d 43850066 

162-1 

Phenyl la

Aerobic Aquatic Metabolism 6.4% @ 100 d 5.3% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

7.2% @ 120 d 3.8% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 
92 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 7 Flefenacet thioglycolate sulfoxide 4-Fluoro-N-methylethyl-aniline sulfenyldiacetic acid amide 

Aerobic Soil Metabolism 

3.7% @ 180 d 2.8% @ 365 d 43441141 

162-1 

Phenyl la

3.3% @ 56 d Not detected @ 120 d 43850058 

162-1 

Phenyl la

5.5% @ 28 d Not detected @ 120 d 43850058 

162-1 

Phenyl la(Laacher

1.9% @ 28 d Not detected @ 120 d 43850058 

162-1 

Phenyl la

Anaerobic Soil Metabolism2.6% @ 30 d Not detected @ 210 d 43850059 

162-2 

Phenyl la

Aerobic Aquatic Metabolism 2.0% @ 157 d 2.0% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

1.89% @ 60 d 1.38% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 
93 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 8 Flufenacet alcohol N-(4-fluorophenyl)-2-hydroxyacetamide or N-(4-Fluorophenyl)-2-hydroxy-N-(1-methylethyl)acetamide 

Soil Photolysis 

irradiated- 1.0% @ 30 d dark- 0.4% @ 30 d 

irradiated- 1.0% @ 30 d dark- 0.4% @ 30 d 

43850057 161-3 

Phenyl la

Aerobic Soil Metabolism 2.1% @ 44-65 d Not detected @ 365 d 43441141 

162-1 

Phenyl la

8.1% @ 88 d 8.1% @ 88 d 43850066 

162-1 

Phenyl la

21.2% @ 88 d 21.2% @ 88 d 43850066 

162-1 

Phenyl la

Anaerobic Soil Metabolism 1.4% @ 153 d 0.9% @ 210 d 43850059 

162-2 

Phenyl la

Aerobic Aquatic Metabolism0.7% @ 120 d 0.6% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

1.3% @ 157 d 1.3% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 
94 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Terrestrial Field Dissipation 

0.4 ppm @ 1 d Below LOD (<0.01 ppm) 

@ 554 d 

43850062 164-1 

North Casand  0-6 inch

0.01 ppm @ 1 to 14 d Below LOD (<0.01 ppm) 

@ 466 d 

43850063 164-1 

Wisconsi0-6 inche

Prospective Ground Water Below the LOQ (10 μg/kg) throughout the study 

Below the LOQ (10 μg/kg) at 489 d 

45907901 166-1 

Transformation Product 9 Flufenacet chloroacetanilide N-(4-Fluorophenyl)-2-chloro-N-(1-methylethyl)acetamide 

Aerobic Soil Metabolism 

5.1% @ 44 d Not detected @ 365 d 43441141 

162-1 

Phenyl la

0.4% @ 1 d 0.2% @ 88 d 43850066 

162-1 

Phenyl la

0.4% @ 27 d 0.2% @ 88 d 43850066 

162-1 

Phenyl la
95 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 10 Flufenacet N-isomer N-(4-Fluorophenyl)-N-(1-methylethyl)-5-oxo2-(trifluoromethyl)-1,3,4-thiadiazole-4(5H)-acetamide 

Soil Photolysis

irradiated- 1.6% @ 8-15 d dark- 1.8% @ 15 d 

irradiated- 1.6% @ 30 d dark- 1.5% @ 30 d 

43850057 161-3 

Phenyl la

Aerobic Soil Metabolism2.0% @ 46 d 0.7% @ 88 d 43850066 

162-1 

Phenyl la

1.4% @ 88 d 1.4% @ 88 d 43850066 

162-1 

Phenyl la

Transformation Product 11 Flufenacet thiol dimer 2,2'-Dithiobis[N-(4-fluorophenyl)-N-(1-methylethyl)acetamide] 

Aerobic Soil Metabolism 

0.8% @ 27 d 0.7% @ 88 d 43850066 

162-1 

Phenyl la

Transformation Product 12 Flufenacet thioglycolate 4-Fluoro-N-methylethylaniline thiodiacetic acid amide 

Anaerobic Soil Metabolism 

1.7% @ 60 d 1.4% @ 210 d 43850059 

162-2 

Phenyl la
96 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 13 Flufenacet amine acetate N-(4-Fluorophenyl)-N(1-methylethyl)acetamide 

Anaerobic Aquatic Metabolism 

1.6% @ 63-91 d 1.6% @ 91 d 43850060 

162-3 

Phenyl laloam 

Transformation Product 14 Thiadone-acetate 5-Trifluoromethyl-1,3,4-thiadiazol-2-oxy acetic acid 

Anaerobic Aquatic Metabolism 

1.8% @ 99 d 1.8% @ 99 d 43850061 

162-3 

Thiadiazsandy loa

Transformation Product 15 FAIOCS and Flufenacet acid Cysteine conjugate of 4'Fluoro-Nisopropanolacetanilide and FOE oxalate 

Fish BCF

0.258 mg/kg @ 21 d (nonedible) 0.191 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl lamacroch

Transformation Product 16 FACSO 3-[[2-4-[(4-Fluorophenyl)(1-methylethyl)amino]2-oxoethyl]sulfinyl]analine 

Fish BCF

0.327 mg/kg @ 21 d (nonedible) 0.114 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl lamacroch
97 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 17 FANACSO N-Acetyl-3-[[2-[4-fluorophenyl)(1-nethylethyl)amino]-2-oxoethyl]sulfinyl]alanine 

Fish BCF 

0.444 mg/kg @ 21 d (nonedible) 0.097 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl lamacroch

Transformation Product 18 FOE GSH N-[2-(Carboxmethyl)amino]-1-[[[[2-[(4-fluorophenyl)(1-methylethyl)amino]-2-oxoethyl]thio]methy]-2-oxoethyl]glutamine 

Fish BCF

0.355 mg/kg @ 21 d (nonedible) 0.239 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl lamacroch

Transformation Product 19 FACS S-[2-[(4-Fluorophenyl)(1-methylethyl)amino]-2-oxoethyl]cysteine 

Fish BCF

5.719 mg/kg @ 28 d (nonedible) 5.719 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl la(Lepomis 

0.692 mg/kg @ 21 d (edible) 

0.631 mg/kg @ 28 d (edible) 

43441127/ 43441139 165-4 

Phenyl la(Lepomis 
98 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Transformation Product 20 FANACS Nacetyl-S-[2-[(4-fluorophenyl)(1-methylethyl)amino]-2-oxoethyl]cysteine 

Fish BCF

2.431 mg/kg @ 28 d (nonedible) 2.431 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl la(Lepomis 

0.326 mg/kg @ 21 d (edible) 

0.260 mg/kg @ 28 d (edible) 

43441127/ 43441139 165-4 

Phenyl la(Lepomis 

Transformation Product 21 Flufenacet GLU 

Fish BCF

0.52 mg/kg @ 21 d (nonedible) 0.467 mg/kg @ 28 d (non-edible) 43441127/ 43441139 

165-4 

Phenyl la(Lepomis 

Carbon dioxide Aerobic Soil Metabolism 

50.9% @ 368 d 50.9% @ 368 d 43441135 

162-1 

Thiadiaz

5.9% @ 365 d 5.9% @ 365 d 43441141 

162-1 

Phenyl la

14.2% @ 120 d 14.2% @ 120 d 43850058 

162-1 

Phenyl la
99 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

23.8% @ 120 d 23.8% @ 120 d 43850058 

162-1 

Phenyl la(Laacher

12.0% @ 120 d 12.0% @ 120 d 43850058 

162-1 

Phenyl la

Anaerobic Soil Metabolism 1.8% @ 210 d 1.8% @ 210 d 43850059 

162-2 

Phenyl la

Anaerobic Aquatic Metabolism0.1% @ 91 d 0.1% @ 91 d 43850060 

162-3 

Phenyl laloam soil 

1.4% @ 99 d 1.4% @ 99 d 43850061 

162-3 

Thiadiazsandy loa

Aerobic Aquatic Metabolism 3.4% @ 157 d 3.4% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

1.5% @ 157 d 1.5% @ 157 d 44580203 

162-4 

Phenyl laloam sedsystem) 

15.3% @ 156 d 15.3% @ 156 d 45796112 

162-4 

Thiadiazsilty clay system) 
100 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

15.0% @ 156 d 15.0% @ 156 d 45796112 

162-4 

Thiadiazsilty clay entire sys

Unextracted residues Aerobic Soil Metabolism 

17.7% @ 271 d 16.5% @ 365 d 43441141 

162-1 

Phenyl la

6.9% @ 270 d 6.5% @ 368 d 43441135 

162-1 

Thiadiaz

24.4% @ 19 d 19.5% @ 88 d 43850066 

162-1 

Phenyl la

25.3% @ 88 d 25.3% @ 88 d 43850066 

162-1 

Phenyl la

42.3% @ 120 d 42.3% @ 120 d 43850058 

162-1 

Phenyl la

37.1% @ 120 d 37.1% @ 120 d 43850058 

162-1 

Phenyl la(Laacher

58.0% @ 120 d 58.0% @ 120 d 43850058 

162-1 

Phenyl la

Anaerobic Soil Metabolism 32.6% @ 210 d 32.6% @ 210 d 43850059 

162-2 

Phenyl la
101 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Commen

Anaerobic Aquatic Metabolism 10.0% @ 63 d 6.0% @ 91 d 43850060 

162-3 

Phenyl laloam soil 

0.6% @ 64-99 d 0.6% @ 99 d 43850061 

162-3 

Thiadiazsandy loa

Aerobic Aquatic Metabolism 28.5% @ 157 d 28.5% @ 157 d 44580203 

162-4 

Phenyl laloam sed

46.4% @ 157 d 46.4% @ 157 d 44580203 

162-4 

Phenyl laloam sed

3.3% @ 55 d 2.2% @ 156 d 45796112 

162-4 

Thiadiazsilty clay 

9.6% @ 100 d 7.5% @ 156 d 45796112 

162-4 

Thiadiazsilty clay 
102 

Table C-2. Thiadone as the Test Material transformation products.

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Comments 

Transformation Product 1 Propionic acid conjugate of thiadone

Soil Photolysis 

irradiated- 6.1% @ 10 d dark- 12.0% @ 7 d 

irradiated- 2.9% @ 14 d dark- 2.1% @ 14 d 

45796108 161-3 

Loamy sand soil 

Aerobic Soil Metabolism 10.2% @ 2 d 0.1% @ 10 d 45796109 

162-1 

Loamy sand 

7.0% @ 2 d 0.1% @ 10 d 45796109 

162-1 

Sandy loam 

1.3% @ 1 d Not detected @ 14 d 45796109 

162-1 

Silt loam 

Carbon Dioxide Soil Photolysis 

irradiated- 57.8% @ 14 d dark- 57.6% @ 14 d 

irradiated- 57.8% @ 14 d dark- 57.6% @ 14 d 

45796108 161-3 

Loamy sand soil 

Aerobic Soil Metabolism 63.2% @ 10 d 63.2% @ 10 d 45796109 

162-1 

Loamy sand 

82.1% @ 10 d 82.1% @ 10 d 45796109 

162-1 

Sandy loam 

71.8% @ 14 d 71.8% @ 14 d 45796109 

162-1 

Silt loam 

Anaerobic Aquatic Metabolism 1.9% @ 303 d 1.9 % @ 303 d 45796110 

162-3 

Water-silty clay sedim
103 

Transformation Product Name and Structure 

Maximum Percent of Applied Dose (Interval) 

Percent of Applied Dose at final sampling interval (Interval) 

Study and Guideline number 

Comments 

Aerobic Aquatic Metabolism 10.9% @ 160 d 10.9% @ 160 d 45796111 

162-4 

Water-silty clay sedim

Unextractable residues Aerobic Soil Metabolism 

20.1% @ 7 d 19.5% @ 10 d 45796109 

162-1 

Loamy sand 

8.4% @ 5 d 7.6% @ 10 d 45796109 

162-1 

Sandy loam 

14.7% @ 7-14 d 14.7% @ 14 d 45796109 

162-1 

Silt loam 

Anaerobic Aquatic Metabolism  3.0% @ 61 d 0.8 % @ 303 d 45796110 

162-3 

Water-silty clay sedim

Aerobic Aquatic Metabolism2.4% @ 160 d 2.4% @ 160 d 45796111 

162-4 

Water-silty clay sedim
104 

Appendix D. Sample SWCC and PRZM-GW Files 

Figure D-1. Sample SWCC output file (IL Corn). 

Summary of Water Modeling of Flufenacet_ILCorn and the USEPA 

Standard Pond 

Estimated Environmental Concentrations for Flufenacet_ILCorn are presented in Table 1 for the 

USEPA standard pond with the ILCornSTD field scenario. A graphical presentation of the yearto-year peaks is presented in Figure 1. These values were generated with the Surface & Ground 

Water Concentration Calculator Version 1.14. Critical input values for the model are 

summarized in Tables 2 and 3. 

This model estimates that about 2.1% of Flufenacet_ILCorn applied to the field eventually 

reaches the water body. The main mechanism of transport from the field to the water body is by 

runoff (59.3% of the total transport), followed by spray drift ( 29%) and erosion (11.7%). 

In the water body, pesticide dissipates with an effective water column half-life of 168.7 days. 

(This value does not include dissipation by transport to the benthic region; it includes only 

processes that result in removal of pesticide from the complete system.) The main source of 

dissipation in the water column is metabolism (effective average half-life = 168.9 days) followed 

by volatilization (155961.1 days). 

In the benthic region, pesticide dissipation is negligible (1077.7 days). The main source of 

dissipation in the benthic region is metabolism (effective average half-life = 1077.7 days). The 

vast majority of the pesticide in the benthic region (97.91%) is sorbed to sediment rather than in 

the pore water. 

Table 1. Estimated Environmental Concentrations (ppb) for Flufenacet_ILCorn. 

Peak (1-in-10 yr) 17.4 

4-day Avg (1-in-10 yr) 17.0 

21-day Avg (1-in-10 yr) 16.3 

60-day Avg (1-in-10 yr) 14.6 

365-day Avg (1-in-10 yr) 7.70 

Entire Simulation Mean 5.17 

Table 2. Summary of Model Inputs for Flufenacet_ILCorn. 

Scenario ILCornSTD 

Cropped Area Fraction 1 

Koc (ml/g) 434.4 

Water Half-Life (days) @ 25 °C 77.1 
105 

Benthic Half-Life (days) @ 25 °C 492 

Photolysis Half-Life (days) @ 45 

°Lat 

0 

Hydrolysis Half-Life (days) 0 

Soil Half-Life (days) @ 25 °C 48.2 

Foliar Half-Life (days) 0 

Molecular Wt 363.6 

Vapor Pressure (torr) 2.11e-7 

Solubility (mg/l) 56 

Table 3. Application Schedule for Flufenacet_ILCorn. 

Date (Days 

Since 

Emergence) 

Type Amount (kg/ha) Eff. Drift 

-15 Ground 0.898 0.99 0.062 

Figure 1. Yearly Peak Concentrations 

 
106 

Figure D-2. Sample PRZM-GW output file (WI Sands). 

Table 1. Groundwater Results for Flufenacet_WISands and the Wisconsin Corn - WI 

Central Sands Scenario. 

Peak Concentration (ppb) 12.4 

Post-Breakthrough Mean 

Concentration (ppb) 

 11 

Entire Simulation Mean 

Concentration (ppb) 

 4.12 

Average Breakthrough 

Time (days) 

8188.552 

Throughputs 1.338454 

Table 2. Chemical Properties for Groundwater Modeling of Flufenacet_WISands. 

Koc (ml/g) 434.4 

Surface Soil Half Life (days) 48.2 

Hydrolysis Half Life (days) 0 

Diffusion Coefficint Air (cm2/day) 0.0 

Henry's Constant 0.0 

Enthalpy (kcal/mol) 0.0 

Table 3. Pesticide application scheme used for Flufenacet_WISands. This application 

scheme was applied every year of the simulation. 

Application Days 

Relative to 

Emergence Date 

(05/01) 

Application Method Application Rate 

(kg/ha) 

-15 All pesticide placed at 5.08 cm 

below surface 

0.898 
107 

Figure 1. Aquifer Breakthrough Curve for Flufenacet_WISands and the Wisconsin Corn - 

WI Central Sands Scenario 

 
108 

Appendix E. Sample TREX Files 

Upper Bound Kenaga Residues For RQ Calculation 

Chemical Name: Flufenacet 

 Use 118 

 Formulation 0 

Application Rate 0.8019 lbs a.i./acre 

Half-life 35 days 

Application Interval 0 days 

Maximum # Apps./Year 1 

Length of Simulation 1 year 

Variable application rates? 0.00 

Endpoints 

Avian 

Canary LD50 (mg/kg-bw) 461.00 

Bobwhite quail LC50 (mg/kg-diet) 0.00 

Mallard duck NOAEL(mg/kg-bw) 0.00 

Mallard duck NOAEC (mg/kg-diet) 88.00 

 

Mammals 

LD50 (mg/kg-bw) 589.00 

LC50 (mg/kg-diet) 0.00 

NOAEL (mg/kg-bw) 1.30 

NOAEC (mg/kg-diet) 26.00 

Dietary-based EECs 

(ppm)

Kenaga 

Values 

Short Grass 192.46 

Tall Grass 88.21 

Broadleaf plants 108.26 

Fruits/pods/seeds 12.03 

Arthropods 75.38 

Avian Body 

Ingestion 

(Fdry) 

Ingestion 

(Fwet) % body wgt FI 

Class Weight (g) (g bw/day) (g/day) consumed (kg-diet/day) 
109 

Small 20 5 23 114 2.28E-02 

Mid 100 13 65 65 6.49E-02 

Large 1000 58 291 29 2.91E-01 

 20 5 5 25 5.06E-03 

Granivores 100 13 14 14 1.44E-02 

 1000 58 65 6 6.46E-02 

Avian Body Adjusted LD50 

Weight (g) (mg/kg-bw) 

20 455.71 

100 580.14 

1000 819.47 

Dose-based EECs (mg/kg-bw)

Avian Classes and Body Weights (grams) 

small mid large 

20 100 1000 

Short Grass 219.19 124.99 55.96 

Tall Grass 100.46 57.29 25.65 

Broadleaf plants 123.29 70.31 31.48 

Fruits/pods 13.70 7.81 3.50 

Arthropods 85.85 48.95 21.92 

Seeds 3.04 1.74 0.78 

Dose-based RQs 

(Dose-based EEC/adjusted LD50)

Avian Acute RQs 

Size Class (grams) 

20 100 1000 

Short Grass 0.48 0.22 0.07 

Tall Grass 0.22 0.10 0.03 

Broadleaf plants 0.27 0.12 0.04 

Fruits/pods 0.03 0.01 0.00 

Arthropods 0.19 0.08 0.03 

Seeds 0.01 0.00 0.00 

Dietary-based RQs 

(Dietary-based EEC/LC50 or 

NOAEC)

RQs 

 

 Acute Chronic 

Short Grass #DIV/0! 2.19 

Tall Grass #DIV/0! 1.00 

Broadleaf plants #DIV/0! 1.23 

Fruits/pods/seeds #DIV/0! 0.14 

Arthropods #DIV/0! 0.86 
110 

Mammalian Body 

Ingestion 

(Fdry) 

Ingestion 

(Fwet) % body wgt FI 

Class Weight (g bwt/day) (g/day) consumed (kg-diet/day) 

 15 3 14 95 1.43E-02 

Herbivores/ 35 5 23 66 2.31E-02 

insectivores 1000 31 153 15 1.53E-01 

 15 3 3 21 3.18E-03 

Grainvores 35 5 5 15 5.13E-03 

 1000 31 34 3 3.40E-02 

Mammalian Body Adjusted Adjusted 

Class Weight LD50 NOAEL 

 15 1294.52 2.86 

Herbivores/ 35 1047.41 2.31 

insectivores 1000 453.04 1.00 

 15 1294.52 2.86 

Granivores 35 1047.41 2.31 

 1000 453.04 1.00 

Dose-Based EECs 

(mg/kg-bw)

Mammalian Classes and Body weight 

(grams) 

15 35 1000 

Short Grass 183.49 126.82 29.40 

Tall Grass 84.10 58.12 13.48 

Broadleaf plants 103.21 71.33 16.54 

Fruits/pods 11.47 7.93 1.84 

Arthropods 71.87 49.67 11.52 

Seeds 2.55 1.76 0.41 

Dose-based RQs 

(Dose-based EEC/LD50 or 

NOAEL)

Small mammal Medium mammal Large mammal 

15 grams 35 grams 1000 grams 

Acute Chronic Acute Chronic Acute Chronic 

Short Grass 0.14 64.22 0.12 54.86 0.06 29.41 

Tall Grass 0.06 29.43 0.06 25.14 0.03 13.48 

Broadleaf plants 0.08 36.12 0.07 30.86 0.04 16.54 

Fruits/pods 0.01 4.01 0.01 3.43 0.00 1.84 

Arthropods 0.06 25.15 0.05 21.49 0.03 11.52 

Seeds 0.00 0.89 0.00 0.76 0.00 0.41 
111 

Dietary-based RQs 

(Dietary-based EEC/LC50 or 

NOAEC)

Mammal RQs 

 

Acute Chronic 

Short Grass #DIV/0! 7.40 

Tall Grass #DIV/0! 3.39 

Broadleaf plants #DIV/0! 4.16 

Fruits/pods/seeds #DIV/0! 0.46 

Arthropods #DIV/0! 2.90 

 
112 

Appendix F. Sample KABAM Files 

Table 1. Chemical characteristics of Flufenacet. 

Characteristic Value Comments/Guidance 

Pesticide Name Flufenacet Required input 

Log KOW 3.2 

Required input 

Enter value from acceptable or supplemental study submitted 

by registrant or available in scientific literature.

KOW 1585 No input necessary. This value is calculated automatically 

from the Log KOW value entered above. 

KOC (L/kg 

OC) 434 

Required input 

Input value used in PRZM/EXAMS to derive EECs. Follow 

input parameter guidance for deriving this parameter value 

(USEPA 2002).

Time to steady 

state (TS; days) 3 No input necessary. This value is calculated automatically from the Log KOW value entered above. 

Pore water EEC 

(μg/L) 10.5 

Required input 

Enter value generated by PRZM/EXAMS benthic file. 

PRZM/EXAMS EEC represents the freely dissolved 

concentration of the pesticide in the pore water of the 

sediment. The appropriate averaging period of the EEC is 

dependent on the specific pesticide being modeled and is 

based on the time it takes for the chemical to reach steady 

state. Select the EEC generated by PRZM/EXAMS which has 

an averaging period closest to the time to steady state 

calculated above. In cases where the time to steady state 

exceeds 365 days, the user should select the EEC 

representing the average of yearly averages. The peak EEC 

should not be used. 

Water Column 

EEC (μg/L) 9.07 

Required input 

Enter value generated by PRZM/EXAMS water column file. 

PRZM/EXAMS EEC represents the freely dissolved 

concentration of the pesticide in the water column. The 

appropriate averaging period of the EEC is dependent on the 

specific pesticide being modeled and is based on the time it 

takes for the chemical to reach steady state. The averaging 

period used for the water column EEC should be the same as 

the one selected for the pore water EEC (discussed above). 

Table 3. Mammalian and avian toxicity data for Flufenacet. These are required inputs. 
113 

Animal 

Measure of 

effect (units) Value Species 

If selected 

species is 

"other," 

enter body 

weight (in 

kg) here. 

Avian 

LD50 (mg/kgbw) 461 other 21.6 

 

LC50 (mg/kgdiet) Northern bobwhite quail 

 

NOAEC 

(mg/kg-diet) 88 mallard duck 

 

Mineau Scaling 

Factor 1.15 

Default value for all species 

is 1.15 (for chemical specific 

values, see Mineau et al. 

1996). 

Mammalian 

LD50 (mg/kgbw) 589 laboratory rat 

 

LC50 (mg/kgdiet) N/A other 

 

Chronic 

Endpoint 1.3 

laboratory rat 

 

units of chronic 

endpoint* 

mg/kg-bw 

Table 11. Estimated concentrations of Flufenacet in ecosystem components. 

Ecosystem Component 

Total 

concentration 

(μg/kg-ww) 

Lipid 

normalized 

concentration 

(μg/kg-lipid) 

Contribution 

due to diet 

(μg/kg-ww) 

Contribution 

due to 

respiration 

(μg/kg-ww) 

Water (total)* 9 N/A N/A N/A

Water (freely dissolved)* 9 N/A N/A N/A

Sediment (pore water)* 11 N/A N/A N/A

Sediment (in solid)** 182 N/A N/A N/A

Phytoplankton 680 33985 N/A 679.69

Zooplankton 500 16652 0.28 499.28

Benthic Invertebrates 549 18291 0.81 547.92

Filter Feeders 364 18194 0.52 363.35

Small Fish 705 17633 3.02 702.32

Medium Fish 708 17690 5.72 701.88

Large Fish 706 17649 10.21 695.75

* Units: μg/L; **Units: μg/kg-dw 

Table 12. Total BCFand BAF values of Flufenacet in 

aquatic trophic levels. 
114 

Trophic Level 

Total BCF 

(μg/kgww)/(μg/L) 

Total BAF 

(μg/kgww)/(μg/L) 

Phytoplankton 77 75 

Zooplankton 55 55 

Benthic Invertebrates 60 60 

Filter Feeders 40 40 

Small Fish 77 78 

Medium Fish 77 78 

Large Fish 77 78 

Table 13. Lipid-normalized BCF, BAF, BMF and BSAF values of Flufenacet in aquatic 

trophic levels. 

Trophic Level 

BCF 

(μg/kglipid)/(μg/L) 

BAF 

(μg/kglipid)/(μg/L) 

BMF 

(μg/kglipid)/(μg/kglipid) 

BSAF 

(μg/kglipid)/(μg/kgOC) 

Phytoplankton 3849 3747 N/A 7 

Zooplankton 1835 1836 0.49 4 

Benthic Invertebrates 2014 2017 1.09 4 

Filter Feeders 2004 2006 1.09 4 

Small Fish 1937 1944 1.01 4 

Medium Fish 1937 1950 0.98 4 

Large Fish 1922 1946 1.00 4 

Table 14. Calculation of EECs for mammals and birds consuming fish contaminated by 

Flufenacet. 

Wildlife Species 

Biological Parameters 

EECs (pesticide 

intake) 

Body 

Weight 

(kg) 

Dry Food 

Ingestion 

Rate (kgdry food/kgbw/day) 

Wet Food 

Ingestion 

Rate (kgwet 

food/kgbw/day) 

Drinking 

Water 

Intake 

(L/d) 

Dose 

Based 

(mg/kgbw/d) 

Dietary 

Based 

(ppm) 

Mammalian 

fog/water shrew 0.02 0.140 0.585 0.003 0.322 0.55 

rice rat/starnosed mole 0.1 0.107 0.484 0.011 0.262 0.54 

small mink 0.5 0.079 0.293 0.048 0.209 0.71 

large mink 1.8 0.062 0.229 0.168 0.163 0.71 

small river otter 5.0 0.052 0.191 0.421 0.136 0.71 
115 

large river otter 15.0 0.042 0.157 1.133 0.112 0.71 

Avian 

sandpipers 0.0 0.228 1.034 0.004 0.5612 0.54 

cranes 6.7 0.030 0.136 0.211 0.0739 0.54 

rails 0.1 0.147 0.577 0.010 0.3633 0.63 

herons 2.9 0.040 0.157 0.120 0.0992 0.63 

small osprey 1.3 0.054 0.199 0.069 0.1416 0.71 

white pelican 7.5 0.029 0.107 0.228 0.0756 0.71 

Table 15. Calculation of toxicity values for mammals and birds 

consuming fish contaminated by Flufenacet. 

Wildlife Species 

Toxicity Values 

Acute Chronic 

Dose 

Based 

(mg/kgbw) 

Dietary 

Based 

(mg/kg-diet) 

Dose Based 

(mg/kg-bw) 

Dietary 

Based 

(mg/kgdiet) 

Mammalian 

fog/water shrew 1236.84 N/A 2.73 26 

rice rat/starnosed mole 839.03 N/A 1.85 26 

small mink 553.13 N/A 1.22 26 

large mink 391.12 N/A 0.86 26 

small river otter 302.96 N/A 0.67 26 

large river otter 230.20 N/A 0.51 26 

Avian 

sandpipers 161.69 0.00 N/A 88 

cranes 386.76 0.00 N/A 88 

rails 195.12 0.00 N/A 88 

herons 341.11 0.00 N/A 88 

small osprey 300.66 0.00 N/A 88 
116 

white pelican 393.36 0.00 N/A 88 

Table 16. Calculation of RQ values for mammals and birds consuming 

fish contaminated by Flufenacet. 

Wildlife Species 

Acute Chronic 

Dose 

Based 

Dietary 

Based 

Dose Based Dietary 

Based 

Mammalian 

fog/water shrew 0.000 N/A 0.118 0.021 

rice rat/starnosed mole 0.000 N/A 0.142 0.021 

small mink 0.000 N/A 0.171 0.027 

large mink 0.000 N/A 0.189 0.027 

small river otter 0.000 N/A 0.203 0.027 

large river otter 0.000 N/A 0.220 0.027 

Avian 

sandpipers 0.003 #DIV/0! N/A 0.006 

cranes 0.000 #DIV/0! N/A 0.006 

rails 0.002 #DIV/0! N/A 0.007 

herons 0.000 #DIV/0! N/A 0.007 

small osprey 0.000 #DIV/0! N/A 0.008 

white pelican 0.000 #DIV/0! N/A 0.008 

 
117 

Appendix G. Risk Quotient Method 

Risk characterization integrates the results of the exposure and ecotoxicity data to evaluate the 

likelihood of adverse ecological effects. The means of this integration is called the quotient 

method. Risk quotients (RQs) are calculated by dividing exposure estimates by acute and 

chronic ecotoxicity values. 

 RQ = EXPOSURE/TOXICITY 

 RQs are then compared to OPP's levels of concern (LOCs). These LOCs are used by 

OPP to analyze potential risk to nontarget organisms and the need to consider regulatory action. 

The criteria indicate that a pesticide used as directed has the potential to cause adverse effects on 

nontarget organisms. LOCs currently address the following risk presumption categories: (1) 

acute risks - regulatory action may be warranted in addition to restricted use classification, (2) 

acute restricted use - the potential for acute risk is high, but may be mitigated through restricted 

use classification, (3) acute endangered species - endangered species may be adversely affected, 

and (4) chronic risk - the potential for chronic risk is high regulatory action may be warranted. 

Currently, EFED does not perform assessments for chronic risk to plants, acute or chronic risks 

to insects, or chronic risk from granular/bait formulations to birds or mammals. 

 The ecotoxicity test values (measurement endpoints) used in the acute and chronic risk 

quotients are derived from required studies. Examples of ecotoxicity values derived from shortterm laboratory studies that assess acute effects are: (1) LC50 (fish and birds), (2) LD50 (birds and 

mammals), (3) EC50 (aquatic plants and aquatic invertebrates) and (4) EC25 (terrestrial plants). 

Examples of toxicity test effect levels derived from the results of long-term laboratory studies 

that assess chronic effects are: (1) LOAEL or LOAEC (birds, fish, and aquatic invertebrates) and 

(2) NOAEL or NOAEC (birds, fish and aquatic invertebrates). For birds, mammals, fish and 

aquatic invertebrates the NOAEL or NOAEC generally is used as the ecotoxicity test value in 

assessing chronic effects, although other values may be used when justified. Risk presumptions 

and the corresponding RQs and LOCs, are tabulated below. 

 
118 

Table 1. Risk presumptions for terrestrial animals based on risk quotients (RQ) and levels of concern (LOC). 

Risk Presumption RQ LOC 

Birds 

Acute Risk EEC1/LC50 or LD50/ft2 or LD50/day3 0.5 

Acute Restricted Use EEC/LC50 or LD50/ft2

 or LD50/day (or LD50 < 50 mg/kg) 0.2 

Acute Endangered Species EEC/LC50 or LD50/ft2

 or LD50/day 0.1 

Chronic Risk EEC/NOAEC 1 

Wild Mammals 

Acute Risk EEC/LC50 or LD50/ft2 or LD50/day 0.5 

Acute Restricted Use EEC/LC50 or LD50/ft2

 or LD50/day (or LD50 < 50 mg/kg) 0.2 

Acute Endangered Species EEC/LC50 or LD50/ft2

 or LD50/day 0.1 

Chronic Risk EEC/NOAEC 1 

1

 abbreviation for Estimated Environmental Concentration (ppm) on avian/mammalian food items 2

 mg/ft2

3

 mg of toxicant consumed/day 

 LD50 * wt. of bird 

 LD50 * wt. of bird 

Table 2. Risk presumptions for aquatic animals based on risk quotients (RQ) and levels of concern (LOC). 

Risk Presumption RQ LOC 

Acute Risk EEC1/LC50 or EC50 0.5 

Acute Restricted Use EEC/LC50 or EC50 0.1 

Acute Endangered Species EEC/LC50 or EC50 0.05 

Chronic Risk EEC/NOAEC 1 

1

 EEC = (ppm or ppb) in water 

Table 3. Risk presumptions for plants based on risk quotients (RQ) and levels of concern (LOC).

Risk Presumption RQ LOC

Terrestrial and Semi-Aquatic Plants 

Acute Risk EEC1/EC25 1 

Acute Endangered Species EEC/EC05 or NOAEC 1 

 Aquatic Plants 

Acute Risk EEC2/EC50 1 

Acute Endangered Species EEC/EC05 or NOAEC 1 

1

 EEC = lbs ai/A 

2

 EEC = (ppb/ppm) in water