Page 2 of 71

Problem Formulation for the

Environmental Fate and Ecological Risk, Endangered 

Species, and Drinking Water Assessments in Support 

of the Registration Review of Fenhexamid

N-(2,3-dichloro-4-hydroxyphenyl)-1-methylcyclohexanecarboxamide

CAS No. 126833-17-8

PC Code: 090209

Prepared by:

Katrina White, Ph.D., Biologist (Lead Fate Scientist)

Scott Glaberman, Ph.D., Biologist

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Jim Carleton, Ph.D., Senior Scientist

Thomas Steeger, Ph.D., Senior Science Advisor

Marietta Echeverria, Branch Chief

May 15, 2013
Page 3 of 71

Contents

1. Introduction ............................................................................................................................ 4

2. Conclusions from Previous Risk Assessments....................................................................... 4

2.1. Ecological Risk Assessments....................................................................................... 4

2.2. Drinking Water Exposure Assessments....................................................................... 6

2.3. Clean Water Act Programs .......................................................................................... 7

3. Environmental Fate and Transport......................................................................................... 7

3.1. Physical-Chemical Properties, BCF, and Mobility...................................................... 7

3.2. Laboratory Degradation Studies.................................................................................. 9

3.3. Transformation Products............................................................................................ 11

3.4. Field Dissipation ........................................................................................................ 15

3.5. Monitoring Data......................................................................................................... 16

4. Receptors.............................................................................................................................. 16

4.1. Effects to Aquatic Organisms.................................................................................... 17

4.2. Effects to Terrestrial Organisms................................................................................ 19

4.3. Ecological Incidents................................................................................................... 21

5. Exposure Pathways of Concern and Risk Hypothesis.......................................................... 21

6. Analysis Plan........................................................................................................................ 22

6.1. Residues of Concern .................................................................................................. 22

6.2. Measures of Exposure................................................................................................ 23

6.3. Measures of Effect ..................................................................................................... 23

6.4. Endangered Species Assessments.............................................................................. 24

6.5. Endocrine Disruptor Screening Program................................................................... 24

7. Preliminary Identification of Data Gaps .............................................................................. 25

7.1. Environmental Fate Data ........................................................................................... 25

7.2. Effects Data................................................................................................................ 28

8. Additional Information on Use............................................................................................. 37

9. References............................................................................................................................ 37

9.1. Literature Cited .......................................................................................................... 37

9.2. Studies Submitted by the Registrant.......................................................................... 40

Appendix A. Supplemental Environmental Fate Information....................................................... 46

Appendix B. Screening Level Usage Analysis ............................................................................. 57

Appendix C. SIP/STIR Model Results.......................................................................................... 59

Appendix D. Reference List for OPPTS 835 Guidelines and 850 Guidelines Related to Fate..... 61

Appendix E. AOPWIN V1.92 Output........................................................................................... 63

Appendix F. Currently Registered Products Containing Fenhexamid .......................................... 64

Appendix G. Summary of exposure pathways, endpoints, and models that will be used in the risk 

assessment......................................................................................................................... 65

Appendix H. Preliminary Rough Estimate of Exposure Assuming Unextracted Residues are a 

Residue of Concern........................................................................................................... 66

Appendix I. Toxicity Profile for Fenhexamid. ............................................................................... 68

Appendix J. Data Call-In Justification Tables for Non-guideline Studies.................................... 70
Page 4 of 71

1. Introduction

EFED evaluated the most recent ecological risk and drinking water assessments for fenhexamid

in association with the updated toxicity, exposure, and usage information to determine if 

sufficient data are available and if further updates are needed to support Registration Review. 

Recent risk assessments include a 2007 assessment for the use of fenhexamid on asparagus

(Sutton and Steeger, 2007, D340419) In addition, EFED considered the latest Agency science 

policies and risk assessment methodologies. The structure, chemical name, and other identifiers 

of fenhexamid and its major transformation products can be found in the chemical identity table 

attached to this document (Appendix A).

Fenhexamid (CAS No. 126833-17-8) is an hydroxyanilide fungicide, and its mode of action is 

as a sterol biosynthesis inhibitor in fungi (Orton et al., 2011).

Fenhexamid is currently registered for the following agricultural uses: almonds, asparagus, 

bushberries, caneberries, cherries, cucumbers, flavoring and spice crops, forest conifers, fruiting 

vegetables, ginseng, grapes, kiwi fruit, leafy greens (except spinach), pears, pistachios, 

pomegranates, raspberries, stone fruits, strawberries, and tomatoes. Non-agricultural uses 

include ornamental plants. 

The chemical can be applied by chemigation, airblast, foliar ground spray, and as a dip 

treatment. All end-use products are formulated as water dispersible granules. There are three 

end-use products. Two products only contain fenhexamid and one contains fenhexamid (14.3%) 

and captan (53.6%), a phthalamide fungicide.

1

 Appendix F summarizes currently registered 

products containing fenhexamid. The most recent assessment evaluated use on asparagus at 0.75 

lbs a.i./A with two consecutive applications and a minimum retreatment interval of 7 days. 

Based on the Label Use Information System (LUIS) EFED Table 1 Report completed on October 

30, 2012, the maximum single application rate is 0.75 lbs a.i./A, with a maximum seasonal 

application rate of 3 lbs a.i./A. When the minimum retreatment interval is specified, it is seven 

days. There is some uncertainty with the maximum single application rate for uses on 

ornamentals and forest conifers. The chemical use profile produced by the Biological and 

Economic Assessment Division (BEAD), located in the docket, lists the maximum single 

application rate, minimum retreatment interval, and maximum annual or seasonal application 

rates for the current uses of fenhexamid. The Screening Level Usage Analysis (SLUA) 

developed by BEAD is provided in Appendix B. According to the SLUA, most fenhexamid

used on agricultural use sites is applied to strawberries and grapes.

2. Conclusions from Previous Risk Assessments

2.1. Ecological Risk Assessments

Ecological risk assessments completed on fenhexamid on uses are summarized in Table 1. 

These risk assessments, along with studies submitted to support the registration of fenhexamid,

 

1 The TEP containing multiple active ingredients does have agricultural use patterns and may be applied using 

ground boom equipment. Thus, it may result in spray drift to adjacent water bodies. 
Page 5 of 71

were used to develop this problem formulation. Potential risks identified in these assessments 

are briefly summarized in Table 2 and Table 3 below.

Table 1. Summary of Drinking Water and Ecological Risk Assessments Completed for 

Fenhexamid

Use Site(s) Type of 

Action Year Drinking Water Ecological

Grapes, strawberries, 

ornamentals

New 

Chemical 1999 (Cowles, 1999)

(Cowles and Spatz, 1999, 

D244921+; Cowles and 

Steeger, 1999, D244921)

Pears Section 18 

CA 1999 (Cowles and Steeger, 1999, D257742)

(Cowles and Steeger, 1999, 

D257742)

Almonds,

Stone Fruit Section 3 2000 (Felthousen, 2000, D259999)

(Felthousen, 2000, D259999)

Blueberries, Caneberries, 

Pistachios Section 3 2002 (Sutton, 2002, D279884+) (Sutton, 2002, D279884+)

Kiwi Section 18 

CA 2003 (Sutton, 2003, D285210+) (Costello, 2003, D293198)

Kiwifruit,

Leafy Greens, Fruiting 

Vegetables, Cucumber

Section 3 2003 (Sutton, 2003, D285210+) (Sutton, 2003, D285210+)

Pome Fruit Section 3 2004

2006

(Sutton and Steeger, 2006, 

D326293+)

(Phillips and Costello, 2004, 

D297963)

(Sutton and Steeger, 2006, 

D326293+)

Ginseng, Pomegranate,

Non-bell Pepper, Cilantro Section 3 20052006

(Phillips and Costello, 

2004, D297963; Sutton and 

Steeger, 2006, D326293+)

(Phillips and Costello, 2005, 

D312268+; Sutton and 

Steeger, 2006, D326289+)

Asparagus Section 3 2007 (Sutton, 2007, D338651)

(Sutton and Steeger, 2007, 

D340419)

Fenhexamid was characterized in previous assessments as stable to hydrolysis, though nonpersistent in aerobic environments and slightly persistent in anaerobic environments. 

Fenhexamid has low to moderate mobility in most soils. Fenhexamid’s low persistence in 

aerobic environments will limit the amount of the chemical that is able to migrate into surface 

and ground water (Sutton and Steeger, 2007, D340419). 

The only Agency levels of concern (LOC) exceeded in previous risk assessments are those for 

chronic risk to mammals including Federally-listed threatened and endangered species (hereafter 

referred to as “listed”) (Phillips and Costello, 2005, D312268+; Sutton and Steeger, 2006, 

D326289+)

2

. The LOC exceedances were identified for applications ranging from two 

applications of 0.375 lbs a.i./A (pome fruit; D326293) to four applications of 0.75 lbs a.i./A 

(ginseng; D312268+). Based on uncertainties regarding potential adverse effects to plants (no 

terrestrial plant data are available) and on chronic effects to terrestrial organisms, 16-23 foot 

buffers from naturally vegetated aquatic habitats were previously recommended (Cowles and 

Spatz, 1999, D244921+; Cowles and Steeger, 1999, D257742) (Sutton, 2002, D279884+). 

The following uncertainties were identified in previous risk assessments:

 

2 Chronic LOCs for mammals were not exceeded in the earliest completed risk assessments but were exceeded in 

those completed in 2005 and later. 
Page 6 of 71

Chronic exposure to fenhexamid resulted in decreased neonatal body weights in rats and was 

associated with diminished feed consumption in birds. Feed consumption rates decreased

(i.e., less food consumed with increasing dietary concentration of fenhexamid) in avian 

subacute dietary studies and a chronic avian reproduction study. Whether the reduced feed 

consumption was related to palatability or reflected a chemically-induced anorexia is not 

known; however, the potential to affect feed consumption and neonatal body weights is a 

concern.

Although none of the LOCs were exceeded for aquatic plants, fenhexamid treatment was 

associated with both chlorosis (loss of color) and necrosis (cell death) in aquatic vascular 

plants. No terrestrial plant studies were required, and EFED is not aware of any that have 

been submitted. Therefore, there is uncertainty regarding potential effects on terrestrial 

plants.

In preliminary assessments, there was uncertainty in whether solvents used in fate studies 

increased polymerization of the parent. In 2003 (Sutton, 2003, D274862) data were reviewed 

that indicated that acetonitrile did not significantly affect either the formation of metabolites 

or the behavior (including binding) of fenhexamid in soil as compared with the behavior of 

the compound following application in aqueous solution. Additional data on aerobic soil 

metabolism studies were waived. Conditional registrations were made pending additional 

information on bioconcentration factors and terrestrial field dissipation studies are still 

outstanding.

Table 2. Potential risk concerns identified in previous assessments for fenhexamid1

Birds2 Mammals Terrestrial

Invertebrates

Aquatic 

Vertebrates3

Aquatic 

Invertebrates

Terrestrial

Plants

Aquatic 

Plants

Non-listed -- C -- -- -- No data --

Listed -- C -- -- -- No data --

A = Acute risk; C = Chronic risk; -- = No risk

1 Risk concerns were identified when the RQ exceeded the corresponding level of concern in a previous risk 

assessment.

2 Birds serve as surrogates for terrestrial-phase amphibians and reptiles

3

Fish serve as surrogates for aquatic-phase amphibians

Table 3. Potential environmental concerns identified in previous assessments for 

fenhexamid

Bioaccumulation1 Groundwater 

Contamination2 Sediment Persistence Degrades of Concern

Not assessed No Not assessed No None

1 Based on whether previous assessments indicated this was a risk concern or if previous assessments ran 

Kow Based Aquatic Bioaccumulation Model (KABAM) for chemicals with a log Kow greater than three. 

2

Previous risk assessments did not indicate that residues in ground water were high enough to result in a 

risk concern.

2.2. Drinking Water Exposure Assessments

A drinking water exposure assessment for the use of fenhexamid on asparagus was conducted in 

2007 (Sutton and Steeger, 2007, D340419). Maximum Tier I Estimated Drinking Water 

Concentrations (EDWC) were developed using the Food Quality Protection Act Index Reservoir 

Screening Tool (FIRST, version 1.1.0; dated 12/12/2005) and the regression model Screening 
Page 7 of 71

Concentration in Ground Water (SCI-GROW, version 3.2, dated 7/29/2003). Exposure estimates 

were for fenhexamid (parent only), and were estimated for applications of 0.75 lbs a.i./A applied 

with a 7-day interval and a maximum yearly application rate of 3.0 lbs a.i./A/year. Monitoring 

data were not summarized in the drinking water assessment.

Table 4. Maximum EDWC for fenhexamid

Drinking Water Source EDWC (μg/L)

Acute Chronic

Groundwater 0.0007 0.0007

Surface Water 29 1.1

2.3. Clean Water Act Programs

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

under section 303(d) of the Clean Water Act.3 No Total Maximum Daily Loads (TMDL) or 

section 304(a) ambient water quality criteria have been developed for fenhexamid.

4

 Aquatic life 

benchmarks5have not been established for fenhexamid. Any data submitted or otherwise located 

as part of the Registration Review process may be used to prepare aquatic life benchmarks if 

applicable. 

3. Environmental Fate and Transport

3.1. Physical-Chemical Properties, BCF, and Mobility

Table 5 summarizes the identity information and physical-chemical properties of fenhexamid. 

Fenhexamid, a weak acid, has a log dissociation constant (pKa) of 7.3, and will therefore be 

present in both a conjugate base (anionic) form6, and in neutral form in the environment. The 

water solubility of fenhexamid is a function of the relative amounts of each of these forms as 

influenced by pH. Increasing pH from 5 to 9 resulted in roughly a 50-fold increase in water 

solubility, i.e., from 20 to 1000 mg/L. Fenhexamid is considered nonvolatile from dry nonadsorbing surfaces, water, and moist soil.7

The measured log octanol-water partition coefficient 

(log Kow) decreases with increasing pH and is 3.62, 3.51, and 2.23 at pH 4, 7, and 9 (25oC), 

respectively. Estimated log octanol-air partition coefficients (log KOA) range from 12 to 13. 

These partition coefficients indicate that fenhexamid has the potential to biomagnify in terrestrial 

organisms (Armitage and Gobas, 2007; Gobas et al., 2003; USEPA, 2009c), or to 

bioconcentrate/bioaccumulate in aquatic organisms under some conditions. However, 

 

3

Specific state causes of impairment that make up the national pesticides cause of impairment group are listed at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885.

4

Specific state pollutants that make up the National Pesticides Pollutant Group and have TMDLs are listed at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES.

5 Aquatic Life Benchmarks are available at 

(http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm.

6

Ionizes at the oxygen on the phenyl ring.

7 Based on the volatility classification scheme in Guidance for Reporting on the Environmental Fate and Transport 

of the Stressors of Concern in the Problem Formulation for Registration Review, Registration Review Risk 

Assessments, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk 

Assessments (USEPA, 2010b).
Page 8 of 71

bioconcentration and biomagnification will likely be lower than predicted based on partition 

coefficients alone, since fenhexamid rapidly degrades in soil and aquatic environments, and is 

known to be metabolized in vivo as well (e.g., conjugated with glucuronic acid), based upon 

studies on bluegill sunfish (Lepomis macrochirus). The maximum measured bioconcentration 

factor (BCF) based on total radioactivity observed in bluegill sunfish tissue was 540 L/kg-wet 

weight viscera. Depuration in one BCF study was rapid, with a half-life of less than 1 day. 

Available BCF values are uncertain, as they are based on total radioactivity rather than on parent 

compound alone. 

Fenhexamid is classified as moderately mobile to slightly mobile, with organic-carbon 

normalized Freundlich soil-water distribution coefficients (Kfoc) ranging from 446 to 1,226 L/kgorganic carbon measured in six soils (MRID 44342722)8

. Kfoc values for WAK 7004, a 

transformation product of fenhexamid, range from 2,324 to 5,037 L/kg-organic carbon in four 

soils (MRID 44346723) and the transformation product is classified as slightly mobile. 

Fenhexamid may move into surface water in water or sediment runoff. Fenhexamid may be 

transported into surface water (as indicated by the estimated environmental concentrations,

EECs) and will also partition into sediment.

 

Table 5. Summary of physical-chemical properties of fenhexamid

Parameter Value Source or MRID Comments

PC Code 090209 -- --

CAS Number 126833-17-8 (USEPA, 2012) --

Molecular Formula C14H17Cl2NO2 -- --

Chemical Name N-(2,3-dichloro-4-hydroxyphenyl)-1-

methylcyclohexanecarboxamide -- --

Molecular Weight (g/mole) 302.20 -- --

Water Solubility at 20oC 

(mg/L)

pH Solubility

44346719 --

5-7 20

8.5 200

9.3 1000

Vapor Pressure

oC

Vapor Pressure

44346720 Nonvolatile from dry nonadsorbing surfaces 

Pascal Torr

20 4×10-73×10-9

25 9×10-77×10-9

Henry’s Law constant at 20oc 

(atm-m

3

/mole)

pH Henry’s Law Constant

Calculated1

--

5-7 6×10-11

8.5 6×10-12

9.3 1×10-12

Log Dissociation Constant 

(pKa) 7.3 44346714 Weak Acid

Octanol-Water Partition 

Coefficient (Kow) at 20oC

pH log Kow Kow

44346717

Has the potential to 

bioconcentrate (USEPA, 

2010a)

4 3.62 4200

7 3.51 3200

9 2.23 170

Air-water partition coefficient 

(KAW) at 20oC 

pH Log KAW KAW Calculated1 Non-volatile from water 5-7 -9 2×10-9

 

8 Classification is based on the FAO classification system (USEPA, 2010a)
Page 9 of 71

Parameter Value Source or MRID Comments

8.5 -10 2×10-10

9.3 -10 5×10-11

Octanol-air partition 

coefficient (KOA) at 20oC 

(unitless)

pH Log KOA KOA

Calculated1

Potential to biomagnify in 

terrestrial food chains; 

however, this will likely be 

mitigated by rapid 

degradation rates.2

5-7 12 ~2×1012

8.5 12 7×1011

9.3 13 3×1012

Cwater+soil/Cair 1×109to 2×1011 Calculated1 Non-volatile from moist soil 

Freundlich Organic-carbon 

normalized soil-water 

distribution coefficients 

(L/kg-OC)

Soil Parent WAK 7004

44346722 for 

parent

Acceptable. 1/n range from 

0.76-0.9. Sorption is 

influenced by pH and %OC

Laacher 446 --

Borstel 888 --

Stanley 1024 2324

Howe 1025 2421

Vero 1226 5037

Napa 658 3212 44346723 for 

WAK 7004 Supplemental

Bioconcentration Factor for 

Total Radioactivity

- steady state L/kg-wet 

weight

540 viscera 44346747

Supplemental, pH 6.5-7.1, 

22oC. Parent made up ~43% 

of residues in fish. Values

based on total radioactivity.

36.7-60.1 edible

248-339 viscera

132-185 whole fish

44346746 Supplemental, pH 7.1-7.5. 20-

23oC

1All estimated values were calculated according to “Guidance for Reporting on the Environmental Fate and 

Transport of the Stressors of Concern in Problem Formulations for Registration Review, Registration Review Risk 

Assessments, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk 

Assessments” (USEPA, 2010a). Volatility classifications systems are also provided in the same source.

2 A recent FIFRA Scientific Advisory Panel (SAP) reported, “Gobas et al (2003) concluded that chemicals with a 

log KOA >5 can biomagnify in terrestrial food chains if log KOW >2 and the rate of chemical transformation is low. 

However, further proof is needed before accepting these limits without reservations” (USEPA, 2009c). This was 

also supported by Armitage and Gobas’s work completed in 2007 (Armitage and Gobas, 2007). 

3.2. Laboratory Degradation Studies

Table 6 summarizes other environmental fate data for the parent, and provides half-lives for the 

parent and unextracted residues. Chemicals with half-lives greater than 60 days in soil, water, 

and sediment are considered persistent (USEPA, 2008); therefore, aerobic aquatic and soil 

metabolism half-lives for fenhexamid indicate that it is not persistent. However, there is 

uncertainty in the half-lives due to significant amounts of unextracted residues in the metabolism 

studies. If these unidentified residues were found to be parent, then the compound would be 

classified as persistent. More discussion on this issue is available in Section 3.3. Primary routes 

of degradation are via aerobic soil and aerobic aquatic metabolism. Time for decline in 

concentration/mass by 50% (DT50) in four aerobic soils ranged from two hours to a little more 

than 24 hours for parent alone and 137 to 1239 days for parent and unextracted residues. 

Aerobic soil studies were considered to be supplemental because of the high amounts of 

unextracted residues observed and the uncertainty in whether the carrier solvent increased 

polymerization of the parent. The uncertainty with the carrier solvent causing polymerization is 

no longer an uncertainty because studies showed that there was no difference in results from 

studies conducted with and without the carrier solvent. DT50 values in two aerobic aquatic 

systems ranged from 16 to 17 days for parent and 454 to 734 days for parent and unextracted 
Page 10 of 71

residues. Aqueous photolysis may also be an important degradation mechanism when exposure 

to sunlight is significant, as the DT50 for this pathway was a few hours. Fenhexamid is stable to 

hydrolysis at 25oC pH 5, 7, and 9. Soil photolysis was assumed to be minimal in aerobic systems 

because the percent of applied radioactivity remaining as parent in dark control and irradiated 

samples was similar over time. The study was considered to be supplemental because the 

amount of loss due to soil photolysis alone could not be determined.

Table 6. Summary of transformation studies conducted on fenhexamid

Study

System Details

(Kinetic Equation)

Kinetic Equation 

Fitted Value1

Representative 

Half-life to 

Derive Model 

Input (days)2

Reference Or (MRID),

Study Classification

And Comments DT50

(days)

DT90

(days)

Abiotic 

Hydrolysis

pH 5, 25oC

pH 7, 25 Stable Stable 44346725, Acceptable oC

pH 9, 25oC

Atmospheric 

Degradation

Hydroxyl Radical 

(SFO)

0.61 2.03 Not applicable

Estimated using EPIWEB v.4.1 for 12-hour 

day, 1.5x106 OH molecules/cm3.

k=1.13 days-1; See Appendix E

Direct 

Aqueous 

Photolysis

pH 7, 25oC

Sterile

40oN sunlight

(SFO)

0.08 0.27 SFO T1/2=0.08 MRID 44346726, Acceptable. Corrected for 

40oN latitude. Phenyl ring labeled.

pH 8, 25oC

Natural water

40oN sunlight

(SFO)

0.03 0.1 SFO T1/2=0.1 MRID 44346732, Supplemental-May be used in 

modeling. Phenyl ring labeled. 

Soil 

Photolysis

sandy loam,

pH 7.1, 25oC

Not significant pathway when 

microbial degradation is occurring

44346728, Supplemental. Phenyl ring labeled. 

Portion of loss due to photolysis versus 

microbial degradation could not be determined. 

Up to 47% unextracted residues.

Aerobic Soil 

Metabolism

(20oC)

IN sandy loam/ 

Howe

pH 7.1, 1% OC

(IORE, SFO*)

0.3

1239*

3.3

4115*

TIORE=1.0

SFO 

T1/2=1239*

MRID 44346729, Supplemental-May be used in 

modeling. Phenyl ring labeled. Some soils 

were foreign soils. WRB classifications were 

not provided, and it was not determined 

whether soils were representative of a U.S. use 

site. Up to 75, 58, 69, and 81% unextracted 

residues.

German sand/ 

BBA2.1

pH 5.9, 0.7%OC

(IORE, SFO*)

0.091

376*

2.12

1250*

TIORE=0.637

SFO T1/2=376*

German loam sand/ 

BBA 2.2

pH 6.6, 2.5%OC

(IORE, DFOP*)

1.36

449*

11.2

1920*

TIORE=3.4

DFOP slow 

DT50=634*

German, sandy 

loam/ Laacher

pH 7.0, 1.4%OC

(IORE, DFOP*)

0.378

723*

2.86

2401*

TIORE=0.9

SFO T1/2=723*

IN sandy loam/ 

Howe

pH 7.1, 1% OC

(IORE, DFOP*)

0.125

188*

3.06

823*

TIORE=0.922

DFOP slow 

DT50=273*

MRID 44346730, Supplemental-May be used in 

modeling. Carboxamide ring labeled. No 

replicates. 1.43 mg/kg soil. WRB classifications 

were not provided, and it was not determined 

whether German soil was representative of a 

U.S. use site. Up to 60% unextracted residues.

German, sandy 

loam/ Laacher

pH 7.0, 1.4%OC

0.563

137*

5.00

749*

TIORE=1.51

DFOP slow 

DT50=263*
Page 11 of 71

Study

System Details

(Kinetic Equation)

Kinetic Equation 

Fitted Value1

Representative 

Half-life to 

Derive Model 

Input (days)2

Reference Or (MRID),

Study Classification

And Comments DT50

(days)

DT90

(days)

(IORE, DFOP*)

Aerobic 

Aquatic

(20oC)

German Lake

pH5.6, 3.34% OC 

(SFO)

15.8

734*

52.6

2439*

SFO T1/2=

15.8, 734* MRID 44518701, Acceptable. Phenyl ring 

labeled. Up to 75 and 77% unextracted 

residues. Total system values reported. 

Multiple unidentified minor degradates.

US Lake

pH 7, 3.85% OC 

(SFO)

17.0

454*

56.5

1508*

SFO T1/2=

17.0, 454*

Anaerobic 

Soil (20oC)

IN sandy loam/ 

Howe: DI water 

pH 7.1, 1% OC

(SFO)

115

1026*

381

3408*

SFO T1/2=

115, 1026*

44346731, Acceptable. Phenyl ring labeled. 10 

unidentified minor degradates. Mixed with 

sucralose. Up to 73% unextracted residues. 

System treated with 300 mg HgCl2 had 24% 

unextracted residues. Oxygen content reached 

4-8% during experiment.

WRB=World Resources Base; OC=organic carbon; IN=Indiana; DTX=time for concentration/mass to decline by X 

percentage; SFO=single first order; DFOP=double first order in parallel; IORE=indeterminate order (IORE); SFO 

DT50=single first order half-life; TIORE=the half-life of a SFO model that passes through a hypothetical DT90 of the 

IORE fit; DFOP slow DT50=slow rate half-life of the DFOP fit

* Value calculated for parent and unextracted residues which may or may not be parent. These values are relevant in 

understanding the uncertainty in data due to unextracted residues. 

1 DT50 and DT90 values were calculated using nonlinear regression and SFO, DFOP, or IORE equations. The 

equations can be found in the document, Standard Operating Procedure for Using the NAFTA Guidance to 

Calculate Representative Half-life Values and Characterizing Pesticide Degradation (Bohaty et al., 2012),

2 The value used to estimate a model input value is the calculated SFO DT50, TIORE, or the 2nd DT50 from the DFOP 

equation. The model chosen is consistent with that recommended using the, Guidance for Evaluating and 

Calculating Degradation Kinetics in Environmental Media (USEPA and Canada, 2011). The same kinetic equation 

used to determine the representative model input value was used to describe the DT50 and DT90 results based on 

standard kinetic equations.

3.3. Transformation Products

Fenhexamid has twenty identified degradates (excluding carbon dioxide), three of which are 

major degradates (Figure 2). The maximum percent of applied radioactivity present as the 

specified degradate is shown in Appendix A. Most structures are available in Figure 2, with 

additional information in Appendix A. Many minor degradates were not fully characterized and 

chemical names were only provided for a couple of compounds. Almost all of the identified 

degradates are similar to the parent (an anilide, Figure 1) except for a few changes in functional 

groups or the parent base structure present as a dimer or trimer. This includes the three major 

degradates:

C-C Biphenyl Dimer, 

M4, and 

WAK 7004 (7-Chloro-2-(1-methylcyclohexyl)-1,3-benzoxazol-6-ol).

WAK 7004 was the only degradate analyzed for in the terrestrial field dissipation studies, and it 

was found at a maximum of 28 μg/kg-soil. WAK 7004 was a major degradate in aqueous 

photolysis studies, where it appeared as a major degradate in the first 5-hours and then was 

undetectable after 24 hours. M4 was also a major degradate observed in the aqueous photolysis 

studies, where it increased in amounts up to 26% applied radioactivity (AR) over 24 hours, and 
Page 12 of 71

then was detected at 4% AR at the next sampling point, seven days after application. The C-C 

biphenyl dimer was a major degradate in the soil photolysis study, where it reached 14% AR in 

the first day, decreased to 5% AR on day 7, and was 2.4% AR on the last sampling day (18 d). 

In the aqueous photolysis study, degradates M1 and M2 were only characterized as a mixture of 

up to twelve compounds with the highest amount present as 7%9. Most of the characterized 

structures for M1 and M2 were similar to the parent (an anilide) with different functional groups. 

Succinic acid (CAS No. 110-15-6, butanedioic acid) was also identified as being present in the 

mixture. Maximum amounts of the M1 and M2 mixture were increasing at the end of the 

aqueous photolysis study. A mixture identified as M7 was identified in the anaerobic soil study. 

All of the M7s are also anilides, and are similar to the parent structure.

Figure 1. Structure of anilide

Formation of unextracted residues was the primary loss mechanism in the soil photolysis, aerobic 

soil, aerobic aquatic, and anaerobic soil studies (up to 40 to 80% of applied radioactivity). The 

extraction procedures were similar but slightly different in the various fate studies10 and it is not 

clear whether these extraction procedures were exhaustive. Exhaustive extraction procedures use 

a range of polar and nonpolar solvents. A high percentage of carbon dioxide did form in the 

aerobic studies (18 to 40% of applied radioactivity), indicating that a significant portion of the 

parent (at least the portion associated with the phenyl ring) did mineralize. However, in some 

studies unextracted residues occurred prior to formation of the CO2, suggesting that the 

unextracted residues were not mineralizing, and were not forming with degradation of the parent. 

Lower percentages of carbon dioxide were observed in the soil photolysis and aerobic aquatic 

studies (9 to 13% applied radioactivity). Finally, unextracted residues in some studies peaked in 

the middle of study and extraction recoveries at the beginning of the study were low (as low as 

50%); these observations suggest that the extraction procedures were not exhaustive. Therefore, 

to account conservatively for the uncertainty in the calculated half-lives, unextracted residues 

will be considered as potential residues of concern. Additional information on the identity of 

unextracted residues and on the quality of the extraction procedure would reduce uncertainties in 

 

9 M1 and M2 were two separate peaks observed using high performance liquid chromatography (HPLC). Structures 

of compounds making up these two peaks (M1 and M2) were summarized as at least 12 different compounds with 

four representative structures provided (see page 32 of MRID 44346726).

10 The extraction procedures involved shaking three times in acetone:water:1N HCl (94;5:1) (sometimes in full 

acetone and water for the second and third extraction). Subsamples were refluxed with boiling in methanol for six 

hours. Finally, some samples were subject to pyrophosphate extraction and fractionation. In the terrestrial field 

dissipation study, soils were soxhlet extracted with methanol:water (80:20 v:v) for eight hours, which yielded 77-

91% recoveries of the parent. Solvent solubility studies indicated that fenhexamid was most soluble (>100 g/L) in 

acetone, polyethylene glycol, dimethylformamide, and dimethylsulfoxide (MRID 44346718). Methanol was not one 

of the solvents examined. Not enough information is available to evaluate whether the extractions were exhaustive 

extractions.
Page 13 of 71

the fate of fenhexamid. Residues of concern for human health drinking water were identified by 

the Health Effects Division to be the parent only (Herndon, 1999). This determination may be 

re-visited in Registration Review. Residues of concern for ecological risk were determined by 

EFED in this problem formulation, to be the parent, identified residues that retain the anilide 

base structure of the parent, and unextracted residues. 
Page 14 of 71

Figure 2. Potential Degradation Pathway for Fenhexamid. Bold degradates had greater than 10% applied radioactivity 

associated with the compound in at least one submitted fate study. The studies listed under the degradate name indicate the 

studies that the degradate was observed in and the maximum amount of the degradate observed in the study. 
Page 15 of 71

3.4. Field Dissipation

Four supplemental terrestrial field dissipation studies are available for fenhexamid. These 

studies only provide supplemental information as many did not monitor major degradates, none 

of the studies have environmental chemistry methods (ECM) with supporting independent 

laboratory validation (ILV), nor did they have the replication needed to fully characterize the 

variability in residues expected in the natural environment. Standard terrestrial field dissipation 

studies were completed for two bare ground sites in Canada, and one study examined a cropped 

strawberry plot and a bare plot. A lysimeter study was completed in Watsonville, CA. All four

terrestrial field dissipation studies employed four applications at 0.75 kg a.i./ha each, with a 5-8 

day interval between applications. This is similar to the highest registered use rates for 

agricultural uses, which is 0.75 lb a.i./acre with a maximum seasonal rate of 3 lb a.i./acre. When 

a minimum retreatment interval is provided, it is 7 days11. The field dissipation half-lives ranged 

from <1 to 3 days, which is similar to DT50 values observed in aerobic soil laboratory fate 

studies. A lysimeter study measured a much slower dissipation half-life of 44 days. Reasons for

the higher DT50 in the lysimeter study are unknown; however, it may be noteworthy that 

extraction procedures were different than those used in other studies, and a typical end-use 

product was not used in the study.

Table 7. Summary of Terrestrial Field Dissipation Study Results For Fenhexamid

MRID

(Year)

Study Site, Crop DT50 

(days)

DT90 

(days)

Max. 

Depth 

Max Conc in Soil 

(mg/kg-soil)

Comments

Parent WAK 

7004

44580303 

(1998)

Branchon 

Ontario, bare soil

(strawberries)

<1* NR 15 cm 0.21

NA Supplemental. Less than 5% recovery 

of field spiked samples. Did not 

characterize degradation pathway. No 

ILV. Paraquat applied to site. Storage 

stability had 70-110% recovery. Low 

recoveries observed with method. 

44346724

(1996)

Watsonville, CA 44* NR 15 cm 0.762

Supplemental. TEP not used in study. 

No replicates. Lysimeter study.3.05 

lb/A, 4x, interval not reported in DER. 

Extracted with acetonitrile: 0.1% acetic 

acid (8:2) stirring for 1 hour.

45447501

(2000)

British Columbia, 

bare 3.19+ 18.9+ 15 cm 3.292 0.0280 Supplemental. Not enough samples to 

characterize variability on plot, no 

storage stability information, no ILV. 

Only 1 of 3 major degradates followed.

45447501

(2000)

Abbotsford, 

British Columbia, 

strawberries

3.05# 16.5# 15 cm 2.902 0.0206

NA=not analyzed, NR=not reported; ILV=independent laboratory validation; TEP=typical end-use product

*The single first order equation was used to calculate degradation kinetics.

+ The DFOP equation was used to calculate degradation kinetics.

# The IORE equation was used to calculate degradation kinetics.

LOQ for parent=0.01 mg/kg-soil; LOQ for WAK 7004 =0.005 mg/kg-soil

MRID 44346734(soils not typical of those in U.S.) and 44580302 (time 0 concentrations near detection limit) are 

unacceptable.

 

11 Some labels do not include a minimum retreatment interval.
Page 16 of 71

3.5. Monitoring Data

The following databases and sources were searched on February 8, 2012 for monitoring 

information on fenhexamid:

The United States Environmental Protection Agency (USEPA) STORET Database 

(http://www.epa.gov/storet/dbtop.html)

The United States Geological Survey (USGS) National Water-Quality Assessment 

(NAWQA) Program Data Warehouse 

(http://infotrek.er.usgs.gov/traverse/f?p=NAWQA:HOME:1405517206944567) 

The USGS National Stream Quality Accounting Network (NASQAN) program 

(http://water.usgs.gov/nasqan/)

Fenhexamid was looked for in 10 sediment samples (limit of quantitation (LOQ)=3.2 μg/kg) and 

two surface water samples (LOQ=7.6 ng/L) from three creeks in Georgia located in areas

classified as agricultural, urban, and as “other” in the NAWQA program. Concentrations of 

fenhexamid were below LOQs. It is not known whether fenhexamid use occurred in the areas 

where these samples were collected.

4. Receptors

The most sensitive endpoint for each group of organisms will be used in the risk assessment. 

Assessment endpoints include direct toxic effects on the survival, reproduction, and growth of 

terrestrial and aquatic life, as well as indirect effects, such as reduction in prey base and/or 

modification of habitat. A summary of the available aquatic and terrestrial toxicity data for 

fenhexamid and its degradates is provided in Sections 4.1 and 4.2, respectively. In addition, a 

summary of ecological incidents associated with fenhexamid is provided in Section 4.3. Further 

discussion of potential degradate toxicity is provided in the description of the residues of concern 

for fenhexamid (Section 6.1).

Acute toxicity to fish and aquatic invertebrates is categorized using the system shown in Table 8

(USEPA 2004). Acute toxicity to terrestrial fauna (birds and mammals) is categorized using the 

system shown in Table 9. Acute toxicity categories for plants have not been defined.

Table 8. Categories of acute toxicity for aquatic animals

LC50 (mg/L)

1 Toxicity Category

< 0.1 Very highly toxic

> 0.1 - 1 Highly toxic

> 1 - 10 Moderately toxic

> 10 - 100 Slightly toxic

> 100 Practically nontoxic

1LC50 median lethal concentration to 50% of the organisms tested.
Page 17 of 71

Table 9. Categories of acute toxicity for terrestrial animals

LD50 (mg/kg)1 LC50 (ppm) Toxicity Category

<10 <50 Very highly toxic

10-50 50-500 Highly toxic

51-500 501 - 1000 Moderately toxic

501-2000 1001 - 5000 Slightly toxic

>2000 >5000 Practically nontoxic

1LD50 median lethal concentration to 50% of the organisms tested

4.1. Effects to Aquatic Organisms

Table 10 contains a summary of the most sensitive fenhexamid toxicity data for aquatic 

organisms.

Fenhexamid is moderately toxic to rainbow trout (Oncorhynchus mykiss; LC50 = 1.34 mg a.i./L; 

MRlD 44346742) and bluegill sunfish (LC50 = 3.42 mg a.i./L; MRID 44346741) on an acute 

exposure basis. Since freshwater fish serve as surrogates for aquatic-phase amphibians, the

endpoints for fish apply to aquatic-phase amphibians as well. Acute toxicity testing using 

technical end-product (WG-50; 49% a.i.) on rainbow trout yielded roughly similar toxicity 

estimates (LC50 = 1.23 mg a.i./L; MRID 44523605). A chronic toxicity study of rainbow trout 

(early life-stage) produced a no observed adverse effect concentration (NOAEC) of 0.101 mg 

a.i./L (MRID 44346745) with the most sensitive endpoint being time to swim-up. Trout fry 

treated with as low as 0.391 mg a.i./L exhibited reduced survival.

Fenhexamid is slightly toxic to the freshwater invertebrate Daphnia magna (EC50 >18.8 mg 

a.i./L; MRID 44366507). In tests using technical end-product (WG 50; 49.6% a.i.), fenhexamid 

was practically non-toxic to daphnids (EC50 = 105 mg a.i./L; MRID 44523604). In a 21-day 

chronic toxicity test with daphnids, the NOAEC was 1.0 mg a.i./L (MRID 44346744) with

growth (length) being the most sensitive endpoint.

In estuarine/marine animals, fenhexamid is moderately toxic to sheepshead minnow (Cyprinodon 

variegatus; LC50 = 11 mg a.i./L; MRD 44346743) and mysid shrimp (Americamysis bahia; EC50

= 4.6 mg a.i./L; MRID 4346740) on an acute exposure basis. No data were previously required 

for chronic toxicity to estuarine/marine fish or invertebrates.
Page 18 of 71

Toxicity testing with both nonvascular aquatic green algae (Pseudokirchneriella subcapitata; 

EC50 = 4.15 mg a.i./L; MRID 44518706) and vascular aquatic plants duckweed (Lemna gibba; 

EC50 > 2.3 mg a.i./L; MRID 44731105) yielded similar estimates of toxicity. The percentage of 

duckweed fronds exhibiting necrosis and chlorosis was dependent on the concentration of 

fenhexamid. In studies with technical end-product (WG-50; 49.6% a.i.), green algae was the 

most sensitive aquatic plant species (EC50 = 1.37 mg a.i./L; MRlD 44518710).

Table 10. Most Sensitive Aquatic Toxicity Endpoints for Fenhexamid.

Group

Species

(Common 

Name)

Study Type

(Measured 

Effect)

Test 

Substance 

(% a.i.)

Endpoint

(Test 

Duration)

Toxicity Value

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Freshwater Fish1

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

WG-50

(49%)

LC50

(96 hours)

1.23

(moderately 

toxic)

44523605

(Acceptable)

Chronic: Early 

Life-Stage

(Time to swim 

up)

Technical

(95.9%)

NOAEC

LOAEC

0.101

0.206

44346745

(Acceptable)

Estuarine/

Marine Fish

Cyprinodon 

variegatus

(Sheepshead 

minnow)

Acute

(Survival)

Technical

(≥95%)

LC50

(96 hours)

11*

(slightly toxic)

44346743

(Acceptable)

Freshwater 

Invertebrates

Daphnia 

magna

Acute 

(Immobilization)

Technical

(95.7%)

EC50

(48 hours)

>18.8†

(Slightly toxic 

to practicallynon-toxic)

44366507

(Supplemental)

Chronic lifecycle (growth 

[length]; larval 

survival)

Technical

(95.9%)

NOAEC

LOAEC

1.0

1.9

44346744

(Acceptable)

Estuarine/

Marine 

Invertebrates

Americamysis

bahia

(Mysid shrimp)

Acute

(Survival)

Technical

(95.8%)

LC50

(96 hours)

4.6

(moderately 

toxic)

44346740

(Acceptable)

Vascular Aquatic 

Plants

Lemna gibba

(duckweed)

(Frond number, 

growth rate, 

biomass)

Technical

(97.7%)

EC50

(14 days) >2.3†

44731105

NOAEC (Acceptable)

(14 days) 0.28

Non-Vascular 

Aquatic Plants

Pseudokirchneri

ella subcapitata

(green algae)

(Cell density) WG-50

(49.6%)

EC50

(72 hours) 1.37 44523610

NOAEC (Supplemental)

(72 hours) 0.558

EC50 Effect concentration for 50% of the organisms tested; NOAEC no observed adverse effect concentration

† Non-definitive study endpoint; cannot be used to calculate RQs for risk estimation.

‡ Freshwater fish may be surrogates for aquatic-phase amphibians.

See Appendix I for a full list of available aquatic toxicity endpoints for fenhexamid.
Page 19 of 71

4.2. Effects to Terrestrial Organisms

Table 11 contains a summary of the most sensitive fenhexamid toxicity data for terrestrial 

organisms. 

An avian acute oral toxicity test with bobwhite quail (Colinus virginianus; MRID 44346750) 

resulted in no mortality at either of the two concentrations tested, resulting in a 14-day LD50

value of >2,000 mg a.i./kg-bw. Therefore, fenhexamid is classified as practically non-toxic to 

bobwhite quail on an acute oral exposure basis. No mortalities were observed in avian subacute 

dietary studies conducted with either bobwhite quail or mallard ducks (Anas platyrhynchos), 

resulting in 5-day LC50 values of >4,962 and >5,469 mg a.i./kg-diet, respectively (MRIDs 

44346751 and 44346752). Therefore, fenhexamid is classified as practically non-toxic to 

bobwhite quail and mallard ducks on a subacute dietary exposure basis. However, feed 

consumption among bobwhite quail was dependent on the concentration of fenhexamid in the 

diet. In mallard ducks, there was a decline in average body weights with increasing treatment 

concentration groups during both the exposure and post-exposure periods; in addition, a decrease 

in body weight was observed in the post-exposure period (days 6-8) in mallard ducks treated 

with fenhexamid at 2,500 mg a.i./kg-diet relative to controls.

An avian reproduction study using bobwhite quail (MRID 44346753) did not result in any 

chronic growth or reproductive effects at the highest concentration tested (2074 mg a.i./kg-diet), 

but feed consumption was significantly (P<0.05) reduced at the 458 and 2,074 mg a.i./kg-diet 

levels, and was dependent on the concentration of fenhexamid in the diet. It is unclear if the 

decrease in food consumed was due to food palatability (repellency) or to fenhexamid-induced 

anorexia. Since reduced feed consumption was not associated with reduced body weight in 

treatment groups as compared to the control group, the NOAEC for this study is equal to the 

highest concentration tested (NOAEC: 2074 mg a.i./kg-diet)

Since birds serve as surrogates for reptiles and terrestrial-phase amphibians, and without data to 

the contrary, toxicity estimates for birds will apply to these other taxa as well.

Based on acute oral toxicity studies on rats, fenhexamid is categorized as practically non-toxic to 

rats (Rattus norvegicus; LD50 >5,000 mg/kg-bw; MRID 44346769). In chronic studies with rats 

(MRID 44346803), there were no compound-related effects on mortality, clinical signs, 

behavior, or reproductive parameters for adult animals; however, clinical chemistry and reduced 

organ weights resulted in a parental NOAEC and lowest observed adverse effect concentration 

(LOAEC) of 500 and 5,000 mg/kg-diet, respectively. The neonatal NOAEC and LOAEC were

5500 and 5,000 mg/kg-diet, respectively, based on decreased body weights on lactation days 7, 

14 and 21 for first generation (F1) pups (6-11 % less than controls) and on lactation days 7, 14, 

and 21 for second generation (F2) pups (9-11% less than controls).

Fenhexamid is practically non-toxic to young adult honeybees (Apis mellifera) on acute contact 

and oral exposure bases (MRID 44346755). In the acute contact toxicity study, no mortalities 

occurred at either of the two concentrations tested (100 and 200 μg a.i./bee), resulting in a 48-

hour LD50 of >200 μg a.i./bee. In the acute oral toxicity study with young adult honeybees, 0 
Page 20 of 71

and 13% mortality rates were observed at 100 and 201 μg a.i./bee levels, respectively, resulting 

in a 48-hour LC50 of >201 μg a.i./bee. No sublethal effects were noted.

No acceptable terrestrial plant toxicity data were identified for fenhexamid.

Table 11. Terrestrial toxicity profile for fenhexamid.

Group Species Study Type 

(Effect)

Test 

Substance

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Birds‡

Anas 

platyrhynchos 

(mallard duck)

Sub-acute dietary 

(Survival)

Technical

(95.7%)

LC50

(5 days)

>4,962 mg a.i./kgdiet†

(Practically nontoxic)

44346752

(Supplemental)

Colinus 

virginianus

(Northern 

Bobwhite Quail)

Acute oral 

(Survival)

Technical

(95.7%)

LD50

(14 days)

>2,000 mg a.i./kgbw†

(Practically nontoxic)

44346750

(Supplemental)

Reproductive 

toxicity

(Feed consumption 

rate)

Technical

(95.9%)

NOAEC/ 

LOAEC

(23 weeks)

2,074/>2,074

mg a.i./kg-diet

44346753

(Acceptable)

Mammals

Rattus 

norvegicus

(Norway rat)

Acute oral 

(Survival)

Technical

(95.5%)

LD50

(Survival)

>5,000 mg a.i./kgbw

(Practically nontoxic)

44346769

Rat 2-generation 

reproductive 

toxicity test

(decreased body 

weights)

Technical

(93.8-

95.2%)

NOAEC/

LOAEC

500/5,000 mg 

a.i./kg-diet 44346803

Terrestrial 

Invertebrates

Apis mellifera 

(honeybee)

Acute Contact 

Toxicity 

(Survival) 

Technical

(95.7%)

LD50

(48 hours) >200 μg a.i./bee 44346755(Acceptable)

Acute Oral 

Toxicity 

(Survival) 

Technical

(94%)

LD50

(48 hours) >201 μg a.i./bee

44346755

(Supplemental)

Terrestrial 

Plants No Toxicity Data Available

LC50 lethal concentration for 50% of the animals tested; LD50 lethal dose for 50% of the animals tested; NOAEC no observed adverse effect 

concentration (mg/kg-diet); NOAEC no observed adverse effect concentration (mg/kg-diet)

† Non-definitive study endpoint; cannot be used to calculate RQs for risk estimation.

‡ Birds represent surrogates for terrestrial-phase amphibians and reptiles.

See Appendix I for a full list of available terrestrial toxicity endpoints for fenhexamid.
Page 21 of 71

4.3. Ecological Incidents

A review of the Ecological Incident Information System (EIIS) for incidents involving 

fenhexamid was completed on January 31, 2013. Excluding incidents labeled as either unlikely 

or unrelated, only one incident (I013636-027) was identified in EIIS. This incident involved

ornamental plants in Washington County, Oregon (IO13636-027) where unspecified damage to 6 

acres of tulips was associated with a direct application of fenhexamid in 2002. Several other 

chemicals including isoxaben and glyphosate were included with fenhexamid in a tank mix 

around the time of the incident. Therefore, the likelihood that fenhexamid caused the incident 

was classified as “possible.”

A search of OPP’s aggregate incident report database on January 31, 2013 revealed no incidents 

related to fenhexamid. The Avian Incident Monitoring System of the American Bird 

Conservancy was also queried on January 31, 2013, and did not list any bird incidents associated 

with fenhexamid.12

5. Exposure Pathways of Concern and Risk Hypothesis

The environmental fate properties of fenhexamid and its transformation products indicate that 

direct application, spray drift, and runoff are transport mechanisms potentially relevant to 

ecological exposure. Potential risk to birds and mammals from drinking water exposure to 

fenhexamid was assessed using the screening program SIP (Screening Imbibition Program). 

When the highest available solubility level of fenhexamid (1000 mg/L; pH 9.3) is used in the 

program, there are potential drinking water risk concerns to mammals and birds on a chronic 

exposure basis (Appendix C). Since fenhexamid is classified as practically nontoxic to birds on 

both an acute oral and subacute dietary exposure basis, and to mammals on an acute oral 

exposure basis, the likelihood of adverse effects from acute drinking water exposures is 

considered low. When SIP is run with solubility values at a lower pH (200 mg/L at pH 8.5), there 

are still potential chronic drinking water exposure risks to mammals but not birds. The inhalation 

exposure pathway for birds and mammals was screened using the STIR (Screening Tool for 

Inhalation Risk) screening model, (Appendix C), and no potential risk concerns were found. 

These screening level models indicated that there was a potential exposure at high enough 

concentrations to result in a chronic risk concern for birds and mammals due to exposure to 

fenhexamid residues in drinking water. These models assume exposure occurs at the level of 

solubility and vapor pressure and are very conservative. SIP and STIR are described in detail at: 

http://www.epa.gov/oppefed1/models/terrestrial/index.htm. 

Based on previous ecological risk assessments, fenhexamid has the potential to result in chronic

risk to non-listed and listed terrestrial mammals. However, as the prior assessments did not 

include the minor anilide degradates as fenhexamid residues of concern, the following risk 

hypothesis will be used for this risk assessment: 

Based on environmental fate parameters and potential transport pathways, fenhexamid total 

residues have the potential to reduce survival, reproduction, and/or growth in non-target 

terrestrial animals, aquatic vertebrates and invertebrates, and aquatic plants when used in 

 

12 http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/index.cfm
Page 22 of 71

accordance with the current labels. These non-target organisms include listed as well as nonlisted species.

Exposure pathways of concern for fenhexamid include spray drift, runoff, residues on foliage, 

residues in drinking water, bioconcentration/bioaccumulation, and residues in irrigation water. A 

risk assessment for sediment dwelling organisms will be performed when the risk assessment is 

completed. Appendix G summarizes the toxicity endpoints, exposure pathways, and models 

that will be used in the fenhexamid registration review risk assessment. 

6. Analysis Plan

6.1. Residues of Concern

The stressors of ecological concern for aquatic and terrestrial organisms are fenhexamid and 

degradates that retain the anilide structure similar to the parent. Residues that retain the anilide 

structure include the following: WAK 7004, M4, BBJ98-8, M1, M2, M7, ZE056401, M9/KBR 

5613, KBR3596, BBJ 98-9, BBJ 98-11, BBJ 98-12, KBR 2931, and KBR 6259.13 M3 and M10 

will also be considered residues of concern as their structures are unknown and most degradates 

observed are anilides. Additionally, since there is uncertainty in the identity of unextracted 

residues, they will conservatively be included in the half-life calculations. Because of their 

structural similarity to fenhexamid or uncertainty in the structure, and in the absence of data to 

the contrary, anilide degradates and unextracted residues are presumed to have toxicity similar to 

that of the parent and will therefore be included with fenhexamid as part of total toxic residues

(TTR). In this approach, a single exposure concentration is estimated for total residues and 

compared to a representative toxicity endpoint (normally for the parent). To estimate exposure 

the amounts of the identified residues in fate studies are added and the sum of residues will be 

used to estimate a half-life that is in turn used in model inputs. Sorption coefficients used for 

model inputs are chosen from those for parent or a degradate (measured or estimated for 

degradates using Estimation Program Interface Suite (EPI Suite14) (USEPA, 2011) that is 

expected to be one of the more mobile residues. A TTR approach for the above degradates is the 

default option for risk assessment if suitable toxicity information on these degradates is not 

available. However, if suitable degradate toxicity data and environmental fate data are submitted 

or located through the ECOTOX database (USEPA, 2009a), there is the potential to derive 

exposure and risk values for these degradates independently. 

Residues of concern for human health drinking water were identified by the Health Effects 

Division to be the parent only (Herndon, 1999). This determination may be re-visited in 

Registration Review. 

Determinations on residues of concern may be revisited if new fate or toxicity becomes

available.

 

13 Current modeling for terrestrial plants does not consider environmental fate data. Therefore, a total residue 

approach does not influence the plant risk assessment. In the model used to estimate exposure to terrestrial animals 

(TREX), the foliar dissipation rate could be influenced if a total residue approach is used in the risk assessment; 

however, if a 35-day default dissipation rate is used in TREX, fate data do not influence the risk assessment.

14 http://www.epa.gov/opptintr/exposure/pubs/episuite.htm
Page 23 of 71

Mixtures

Evaluation of pesticide environmental mixtures is beyond the scope of this assessment because 

of myriad factors that cannot be quantified based on the available data. Those factors include 

identification of other possible co-contaminants and their concentrations, differences in the 

pattern and duration of exposure among contaminants, and the differential effects of other 

physical/chemical characteristics of the receiving waters (e.g. organic matter present in sediment 

and suspended water). Evaluation of factors that could influence additivity/synergism is beyond 

the scope of this assessment and the capabilities of the available data to allow for an evaluation. 

However, it is acknowledged that not considering mixtures could over- or under-estimate risks 

depending on the type of interaction and factors discussed above. The assessment will, however, 

analyze the toxicity of formulated products (including formulations involving more than one 

active ingredient) and will determine whether formulated products are more toxic than the 

technical grade active ingredient data used for assessing both direct and indirect risks. One 

agricultural product contains both fenhexamid and captan (Appendix F). Captan, a phthalamide 

fungicide, is a non-specific thiol reactant and inhibits respiration of numerous fungi and bacteria 

(USEPA, 2000) and this acts as a fungicide in a different manner than fenhexamid. If use of any 

of these products result in spray drift to a water body, acute aquatic toxicity data on a 

representative typical end-use product should be available for that mixture of ingredients. 

Additionally, terrestrial plant toxicity data should be available for a typical end-use product 

containing the combination of active ingredients.

6.2. Measures of Exposure

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

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

Since the previous exposure assessments were completed, three main changes in standard 

procedures were made: 

1) Transformation rates for fate studies were recalculated according to the North American Free 

Trade Agreement (NAFTA) Guidance for Evaluating and Calculating Degradation Kinetics 

in Environmental Media (Bohaty et al., 2012; NAFTA, 2012). These updated results will be 

used in estimating model inputs for estimating aquatic exposure. 

2) A new model for estimating concentrations in groundwater was developed called the 

Pesticide Root Zone Model – Groundwater (PRZM-GW) (Baris et al., 2013). This model 

will be used along with SCI-GROW to estimate concentrations in ground water.

3) Residues of concern for ecological risk were updated. Estimated environmental 

concentrations will reflect exposure to total anilides.

The most up to date procedures and models will be used in the registration review exposure 

assessments.

6.3. Measures of Effect

Selected toxicity data presented in Section 4 of this problem formulation will be used to calculate 

RQ values. Any relevant additional information submitted by the registrant or found in the open 
Page 24 of 71

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

studies are identified using EPA’s ECOTOXicity (ECOTOX)15 database, 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.

6.4. Endangered Species Assessments

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

Agency will evaluate risks to listed species from registered uses of pesticides in Registration 

Review. These assessments will be conducted in accordance with standard EPA procedures and 

good scientific judgment. The process for evaluating potential risks to listed species is further 

described in the Overview Document at 

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

6.5. Endocrine Disruptor Screening Program

As required by FIFRA and the Federal Food Drug and Cosmetic Act (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. As part of its 

reregistration decision, EPA reviewed these data and selected the most sensitive endpoints for 

relevant risk assessment scenarios from the existing hazard database. However, as required by 

FFDCA section 408(p), fenhexamid is subject to the endocrine screening part of the Endocrine 

Disruptor Screening Program (EDSP). 

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. 

 

15 http://cfpub.epa.gov/ecotox/
Page 25 of 71

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. Fenhexamid is 

not among the group of 58 pesticide active ingredients on the initial list to be screened under the 

EDSP. Accordingly, as part of Registration Review, EPA will issue future EDSP orders/data 

call-ins, requiring the submission of EDSP screening assays for fenhexamid. For further 

information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, 

future lists, the test guidelines and the Tier 1 screening battery, please visit our website: 

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

7. Preliminary Identification of Data Gaps 

7.1. Environmental Fate Data

Table 10 identifies environmental fate studies by MRID that provide data on fenhexamid for 

each guideline requirement, as well as study classifications and whether or not further data are 

needed in order to support risk assessment. Several fate studies are needed to better characterize

and reduce significant uncertainties on the environmental fate and transport of fenhexamid.

There are conditional registrations pending additional data on terrestrial field dissipation and fish 

bioconcentration16. The studies listed below will decrease the uncertainty in determining the 

potential exposure to the pesticide. 

Aerobic Soil Metabolism (OPPTS Guideline Number 835.410017) for parent

Aerobic Aquatic Metabolism (OPPTS Guideline Number 835.430018) for parent

Anaerobic Aquatic Metabolism (OPPTS Guideline Number 835.440019) for parent

Terrestrial Field Dissipation Study (OPPTS Guideline Number 835.610020) using a 

typical end-use product with corresponding Environmental Chemistry Methods (ECM) 

for Soil (OCSPP Guideline 850.610021) for parent and major degradates. The ECM 

should have an independent laboratory validation (ILV). If valid ECM with ILV and 

storage stability data are submitted for MRID 45447501 that may be used to fulfill this 

guideline. If additional terrestrial field dissipation studies are conducted, anilide 

degradates should be analyzed.

Environmental Chemistry Methods for Water (OCSPP Guideline 850.6100) for parent 

and major degradates

Fish Bioconcentration Study (OCSPP Guideline 850.173022) for parent

 

16 A waiver request for a fish bioconcentration study was submitted by the registrant in 2003. EFED did not concur 

with the waiver request (Sutton, 2003, D274862).

17 USEPA. 2008. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0038

18 USEPA. 2008. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0039

19 USEPA. 2008. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0039

20 USEPA. 2008. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0040

21 USEPA. 2009. http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0154-0008

22 USEPA. 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/

Drafts/850-1730.pdf
Page 26 of 71

Due to the uncertainty in the identity of the unextracted residues as described in Section 3.3

additional data are recommended (aerobic soil, aerobic aquatic metabolism, and anaerobic 

aquatic metabolism) to better understand whether these residues are of concern. EFED 

recommends that a range of solvents with different polarities be used in the studies to ensure that 

the extraction procedures are exhaustive for parent and transformation products. Once 

exhaustive extraction procedures are identified in preliminary experiments, studies should be 

completed using the exhaustive extraction procedures. It is recommended that studies be 

completed with both the phenyl and carboximide rings radiolabeled so that all potential 

degradates may be followed. This would reduce uncertainty in the potential that carboxamide 

degradates are forming that were not followed in fate studies. In lieu of additional data being 

submitted, EFED will assume that unextracted residues are potential residues of concern for the 

risk assessment. Characterization of uncertainty will be explored by also calculating risk 

quotients by assuming that unextracted residues are not residues of concern.

In addition to the studies recommended for data call in, the registrant is encouraged to submit the 

following information:

WRB Soil Classifications for Foreign Soils: Many of the fate studies were conducted on 

foreign soils. Additional information on the World Resource Base (WRB) classifications for 

studies conducted on foreign soils would reduce uncertainty in determining whether the 

results apply to soils expected to occur in the United States.

Batch Equilibrium Data on Degradates: Often when a TTR approach is used in risk 

assessment, additional data on sorption coefficients for other residues of concern are 

recommended. Most of the fenhexamid degradates were minor degradates in aerobic soil and 

aerobic aquatic metabolism studies. Therefore, it was determined that EFED would rely on 

the available sorption coefficients for WAK 7004 and fenhexamid. EPI Suite may also be 

used to estimate a sorption coefficient for some degradates. EFED encourages the registrant 

to submit any batch equilibrium data that may be available on degradates.

Sensitive ECM: In addition to the ECM and ILV requests above, any other ECMs that the 

registrant has available may be useful for others to have available for monitoring. Having 

access to sensitive methods (and standards) using a variety of instruments would enable State

Agencies and other interested third parties to investigate incidents or other impacts associated 

with fenhexamid use and could provide Agency with a better set of field data than we have at 

the present to assess the risk. These methods could be specific to fenhexamid and/or its 

transformation products, or multi-residue methods for multiple compounds that include 

fenhexamid and/or its degradates. These methods would add to the methods already 

available for monitoring. 

Table 12. Submitted environmental fate data for fenhexamid

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(Acc. No. 

or MRID)

Study 

Classification

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions EPA will Make in 

Absence of Data

835.2120 Hydrolysis 44346725 Acceptable No

835.2240 Aqueous 

photolysis

44346726 Acceptable No

44346732 Supplemental No

835.2410 Soil photolysis 44342728 Supplemental No
Page 27 of 71

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(Acc. No. 

or MRID)

Study 

Classification

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions EPA will Make in 

Absence of Data

835.4100 Aerobic soil 

metabolism

44346729 Supplemental

Yes

High levels of unextracted residues were observed in 

available studies and there is uncertainty in whether 

the extraction procedures were exhaustive. 

Therefore, additional data are needed to better 

understand the uncertainty in the identity of the 

unextracted residues. In lieu of additional data, 

EFED will assume that unextracted residues are 

residues of concern in the risk assessment.

44346730 Supplemental

835.4200 Anaerobic soil 

metabolism 44346731 Acceptable No

Data are typically required for four soils. Currently, 

data are only available on one anaerobic soil system. 

In lieu of additional data, EFED will characterize 

anaerobic metabolism based on the study available. 

While anaerobic soil metabolism data are required 

according the 40 CFR 158.1300, these data are not 

typically used in exposure modeling and exposure to 

humans in ground water is currently not a concern. 

Therefore, these data would likely have little impact 

on the risk conclusions.

835.4300

Aerobic 

aquatic 

metabolism

44518701 Acceptable Yes

High levels of unextracted residues were observed in 

available studies and there is uncertainty in whether 

the extraction procedures were exhaustive. 

Therefore, additional data are needed to better 

understand the uncertainty in the identity of the 

unextracted residues. In lieu of additional data, 

EFED will assume that unextracted residues are 

residues of concern in the risk assessment.

835.4400

Anaerobic 

aquatic 

metabolism

No data submitted Yes

Data are required for two water/sediments systems. 

In lieu of additional data, EFED will assume the 

anaerobic soil metabolism value is representative of 

anaerobic aquatic metabolism rates and will apply a 

3-fold uncertainty factor (DT50×3) to estimate a 

model input value. Additionally, there were high 

levels of unextracted residues in the anaerobic soil 

study. In lieu of additional data, EFED will assume 

that unextracted residues are residues of concern in 

the risk assessment.

835.1230 Adsorption/ 

desorption

44346722 

(Parent) Acceptable

No

Data are currently required for the parent on five soils 

and one sediment. Data are available for parent for 

six soils. Additional data are needed to characterize 

sorption of fenhexamid to one sediment. In lieu of 

additional data, EFED will use available sorption 

coefficients to estimate a mean sorption coefficient in 

modeling. Additional data were not requested as they 

are not expected to substantially impact the risk 

conclusions.

44346732 

(WAK 

7004)

Supplemental

835.6100

Terrestrial 

field 

dissipation

44580303 Supplemental

Yes

MRID 45447501 was submitted to fulfill this open 

data requirement. This study does not have an ILV, 

storage stability data, and only monitored 1 of 3 

major degradates. Additionally, several of the minor 

44346724 Supplemental

45447501 Supplemental

44346734 Unacceptable
Page 28 of 71

OCSPP 

Guideline

Data 

Requirement

Submitted 

Studies 

(Acc. No. 

or MRID)

Study 

Classification

Are data 

needed to 

conduct risk 

assessment?

Justification and Assumptions EPA will Make in 

Absence of Data

44580302 Unacceptable

degradates retain the anilide structure of the parent 

and are considered residues of concern. Therefore, 

additional information on terrestrial field dissipation 

is still needed. In lieu of additional data, there will be 

uncertainty in how well the laboratory fate studies 

reflect what occurs in the field. Submission of an 

ILV for the ECM used in MRID 45447501 and 

storage stability information may eliminate the need 

for additional information on this uncertainty.

850.6100 Analytical 

method in soil 44346734 Not classified

Yes

These studies are not standard environmental 

chemistry method studies. The studies examined 

degradation in soil and sediment. The environmental 

chemistry method components of the studies were 

reviewed. Methods are not the same methods used in 

the terrestrial field dissipation studies (e.g., MRID 

45447501). Additionally ECMs do not have a 

corresponding ILV. This is a standard data 

requirement to support terrestrial field dissipation 

studies.

Analytical 

method in 

sediment

44346731 Not classified

Analytical 

method in 

freshwater

no data submitted

An ECM and ILV are needed with a limit of 

quantitation (LOQ) for the parent below 0.06 mg/L 

that may be used in monitoring.1 All major degradates 

should be included in the method and have an 

associated LOQ and limit of detection (LOD) lower 

than levels that would result in a risk concern. 

Additionally, it would be very helpful for the method 

to be able to measure other anilide degradates.

Analytical 

method in salt 

water

44346738 Not classified No --

Analytical 

method in 

plant tissue

Not 

submitted 

to U.S.

Not reviewed No --

850.1730 Fish BCF

44346747 Supplemental

Yes

Radioactivity was not fully characterized in available 

studies. Fish BCF studies are still needed to fully 

understand the potential for bioconcentration of 

fenhexamid. In lieu of additional data, KABAM will 

be used to evaluate risk based on measured Kow and 

Koc.

44346746 Supplemental

ILV=independent laboratory validation; ECM=environmental chemistry method; BCF=bioconcentration factor

1 The LOQ is based on the 96-hour LC50 of 1.23 mg a.i./L for the rainbow trout and an LOC of 0.05 (MRID 

44523605).

7.2. Effects Data
Page 29 of 71

Table 13 identifies all available ecological effects studies for fenhexamid by MRID, as well as a 

description of whether further data are needed to support risk assessment.

Table 13. Submitted terrestrial and aquatic animal ecological effects data for fenhexamid

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

Avian and Mammalian Testing

850.2100

Avian acute oral

toxicity, 

waterfowl—

TGAI

None N/A No

Avian acute oral

toxicity, upland 

game bird 

species—TGAI

44346750 Supplemental No

Only two dose levels tested (2000 

mg a.i./kg-bw), but no mortality 

occurred at any test level. There 

were some indications of frank 

sublethal effects to body weight in 

birds treated with fenhexamid at 

1050 mg a.i./kg-bw. 

According to the EFED NonDefinitive Endpoint Guidance 

Policy, additional study data would 

typically be recommended here 

because exposure levels were not 

tested up to 10x the EEC (e.g., peak 

short grass EEC for birds is 383.47

mg a.i./kg-bw based on 0.75 lbs 

a.i./A application rate of 

fenhexamid to ginseng at two 

applications per seasons with a 

retreatment interval of 7 days); 

However, since a passerine acute 

oral toxicity study (OCSPP 

850.2100) is already being 

recommended, and since passerines 

tend to be more sensitive to feed 

consumption/body weight effects 

than upland game birds, additional 

toxicity testing is not being 

recommended at this time. 
Page 30 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

Avian acute oral

toxicity, passerine 

species—TGAI

None N/A Yes

Part of 40 CFR Part 158 data 

requirements as of December 2007; 

moreover, affects on feed 

consumption observed in other 

avian studies may impact passerines 

to a greater degree given their food 

intake requirements; in addition, 

only one avian acute toxicity study 

is available for fenhexamid, rather 

than the two species indicated in the 

guidelines (risk to passerine birds 

will be assumed in the absence of 

recommended data)

850.2200

Avian dietary 

toxicity, 

waterfowl 

species—TGAI

44346752 Supplemental No

Non-definitive endpoint of >4,962 

mg a.i./kg-diet is not greater than 10 

times the dietary EEC for all uses 

and/or food items

Avian dietary 

toxicity, upland 

game bird—

TGAI

44346751 Supplemental No

Non-definitive endpoint of >5,469 

mg a.i./kg-diet is not greater than 10 

times the dietary EEC for all uses 

and/or food items

850.2300

Avian 

reproduction, 

waterfowl 

species—TGAI

None N/A No

Study previously waived based on 

low acute oral and sub-acute dietary 

toxicity and lack of reproductive 

effects in the bobwhite quail chronic 

toxicity test (MRID 44346753).

850.2300

Avian 

reproduction, 

upland game bird 

species—TGAI

44346753 Acceptable No

850.2400 Wild mammal 

toxicity—TGAI None N/A No

Not triggered based on ecotoxicity 

data, predicted EECs, fate 

properties, and use pattern criteria.

850.2500

Simulated or 

actual field 

testing—TEP

None N/A No

Not triggered based on ecotoxicity 

data, predicted EECs, fate 

properties, and use pattern criteria.

Aquatic Animal Testing

850.1010

Freshwater 

invertebrate, 

acute toxicity—

TGAI

44366507 Supplemental No

Freshwater 

invertebrate, 

acute toxicity—

TEP

44523604 Supplemental No
Page 31 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

850.1025

Estuarine/Marine 

Mollusk acute 

toxicity—TGAI

None N/A Yes

EFED previously waived this study, 

given the slight to moderate toxicity 

of fenhexamid to aquatic organisms; 

however, in the two other anilide 

fungicides (boscalid; metalaxyl) for 

which Eastern oyster and mysid 

shrimp acute toxicity data are both 

available, the oyster was the more 

sensitive of the two species; in 

addition, oyster data would provide 

a firmer basis for informing risk 

estimates of the many (~123) listed 

freshwater mollusk species23

850.1035

Estuarine/Marine 

crustacean acute 

toxicity—TGAI

44346740 Acceptable No

Precipitate observed at highest test 

level, but centrifugation performed 

prior to measurements

Estuarine/Marine 

crustacean acute 

toxicity—TEP 

(Fenhexamid/

Captan 

Co-formulation; 

EPA Reg. No. 

66330-48)

None N/A Yes

Acute toxicity data for this multi-a.i. 

product is recommended due to the 

potential for spray drift and

uncertainty concerning how the two 

chemicals, together, would affect 

aquatic organisms; estuarine/marine 

organisms are recommended for 

testing since they are the most 

sensitive to fenhexamid TGAI on an 

acute exposure basis.

850.1075

Freshwater fish, 

acute toxicity, 

warm water 

species—TGAI

44346741 Acceptable No

Freshwater fish, 

acute toxicity, 

cold water 

species—TGAI

44346742 Acceptable No

Freshwater fish, 

acute toxicity, 

cold water 

species—TEP 

(WG-50)

44523605 Acceptable No

 

23 Number of federally listed mollusks based on the US Fish And Wildlife Endangered Species Program website: 

http://www.fws.gov/endangered/species/us-species.html
Page 32 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

Estuarine/Marine 

fish acute 

toxicity—TGAI

44346743 Acceptable No

Precipitate at two highest 

concentrations, but centrifugation 

performed prior to measurements; 

mean-measured concentrations did 

not appear to have been affected

850.1300

Freshwater 

invertebrate,

reproduction 

test—TGAI

44346744 Acceptable No

850.1350

Estuarine/marine 

invertebrate,

reproduction

test—TGAI

None N/A Yes

Mysid shrimp (E/M invertebrate) are 

approximately 20 times more 

sensitive than Daphnia magna (FW 

invertebrate) on an acute exposure 

basis. Therefore, a chronic E/M 

invertebrate study is being 

recommended to account for this 

potential sensitivity. In addition, 

there is no available fate information 

to suggest that fenhexamid would 

not reach the estuarine or marine 

environments. (In the absence of this 

data, risk to estuarine/marine 

invertebrates will be assumed; an 

acute-to-chronic ratio cannot be used 

to derive a chronic toxicity value for 

the mysid shrimp since the 

freshwater acute toxicity value for 

daphnids is non-definitive)

850.1400

Freshwater fish, 

early life stage 

test—TGAI

44346745 Acceptable No

Saltwater fish, 

early life stage 

test—TGAI

None N/A No

Based on acute toxicity data, E/M 

fish do not appear to be as sensitive 

to fenhexamid as FW fish; therefore, 

additional data is not expected to 

change the risk picture.
Page 33 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

850.1500

Freshwater fish 

life cycle test None N/A No

Aquatic EECs for some previous 

uses (e.g., ginseng; 60-day EEC 

0.0136 mg/L) are > 0.1 of the FW 

fish early life-stage (ELS) NOAEC 

(0.1 mg a.i./L); however, since there 

were no chronic reproductive effects 

to birds at any fenhexamid 

concentration tested (MRID 

44346753), and since the NOAEL 

values for pup and adults occurred at 

the same test level (5000 ppm) in the 

rat 2-generation reproduction study 

(MRID 44346803), there does not 

appear to be sufficient rationale for 

recommending a fish fully life cycle 

study. 

Estuarine/marine 

fish life cycle test None N/A No

850.1950

Simulated or 

actual field 

testing for aquatic 

organisms

None N/A No

Higher tier testing to address risk 

uncertainties have not been 

identified at this time

Sediment Testing

850.1735

Whole sediment 

10-d freshwater 

invertebrate—

TGAI

None N/A Yes

Data requirement triggered since 

some KOC and log Kow values in 

submitted fate studies were above 

1,000 and 3.0, respectively (see 

Appendix J and data justification 

below table for further details) 

850.1740

Whole sediment 

10-d 

estuarine/marine 

invertebrate—

TGAI

None N/A Yes

Data requirement triggered since 

some KOC and log Kow values in 

submitted fate studies were above 

1,000 and 3.0, respectively (see 

Appendix J and data justification 

below table for further details)

Agencywide 

guideline

Whole sediment 

chronic 

freshwater and/or 

marine 

invertebrate—

TGAI

None N/A Yes

Data are recommended pending the 

outcome of the 10-day sediment 

toxicity studies (850.1735; 

850.1740) (see Appendix J and 

data justification below table for 

further details)
Page 34 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

Insect Pollinator Testing

850.3020

Honeybee acute 

contact toxicity—

TGAI

44346755 Acceptable No

OECD 213

Honeybee acute 

oral toxicity 

study—TGAI 

44346755 Supplemental Yes

Submitted under EPPO Guideline 

No. 17024; two-concentration test; 

multiple mortalities at higher test 

level (201 μg/bee or 1,570 mg/kg); 

did not test high enough to preclude 

listed species risk for some uses 

(e.g., LC50 of 1,570 is less than 20x 

the ginseng tall grass EEC of 271 

mg/kg)

850.3030

Honeybee 

toxicity of 

residues on 

foliage—TEP

None N/A No Data requirement not triggered

850.3040 Field testing for 

pollinators None N/A No

Field testing to address risk 

uncertainties have not been 

identified at this time

NonguidelineLarval Toxicity 

Test—TGAI None N/A Yes

Recommended since data are only 

available on the toxicity of 

fenhexamid to young adult bees; no 

information is available on toxicity 

of fenhexamid to honeybee brood. 

A honeybee larval toxicity test is 

part of EFEDs current screening 

process for terrestrial invertebrates.

It is recommended that a protocol be 

submitted before conducting this 

test.

See Appendix J for further 

justification for recommending this 

study.

Terrestrial Plant Testing

850.4100

Seedling 

emergence (10 

species)—TEP

(representative 

fenhexamid 

single a.i. 

formulation)

None N/A Yes

Submitted study should test up to 

highest currently registered 

application rate of fenhexamid.

Terrestrial plant toxicity studies with 

the fenhexamid/captan coformulated product are being 

 

24 https://secure.fera.defra.gov.uk/beebase/index.cfm?sectionid=64
Page 35 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

Seedling 

emergence (10 

species)—TEP

(Fenhexamid/

Captan 

Co-formulation; 

EPA Reg. No. 

66330-48)

None N/A Yes

recommended since it represents a 

different typical end-use product 

than formulations containing 

fenhexamid only. In addition, both 

compounds are fungicides and may 

result in increased phytotoxic effects 

to non-target plants.

If terrestrial plant toxicity studies are 

only submitted for the 

fenhexamid/captan formulation, then 

this data will be used to estimate risk 

of all fenhexamid formations (both 

single and multi-a.i.) to terrestrial 

plants during risk assessment. If 

terrestrial plant toxicity studies are 

only submitted for a single a.i. TEP 

(i.e., fenhexamid only), risk to 

terrestrial plants will be assumed for 

the fenhexamid/captan formulation. 

850.4150

Vegetative vigor 

(10 species)—

TEP(representativ

e fenhexamid 

single a.i. 

formulation)

None N/A Yes

Vegetative vigor 

(10 species)—

TEP

(Fenhexamid/

Captan 

Co-formulation; 

EPA Reg. No. 

66330-48)

None N/A Yes

Aquatic Plant Testing

850.4400

Aquatic plant 

growth, vascular 

plant — TGAI

44731105 Acceptable No

If uses result in peak EECs that are 

near or above 2.3 mg/L, then 

additional data would be needed. 

The most recent peak EECs for 

ginseng were 0.024 mg/L.

850.4500*

Aquatic Plant, 

freshwater green 

alga species—

TGAI 

44518706 Supplemental No

44518705 Invalid No

Additional data are not needed as 

there is an existing green algae study 

(MRID 44518706) that can be used 

for risk assessment

Aquatic Plant, 

freshwater 

diatom—TEP

None N/A Yes

Study should test up to highest 

application rate and/or aquatic EECs 

as defined in this problem 

formulation or previous risk 

assessments

Aquatic Plant, 

marine diatom —

TEP

None N/A Yes

Study should test up to highest 

application rate and/or aquatic EECs 

as defined in this problem 

formulation or previous risk 

assessments
Page 36 of 71

Guideline Description—

Test Substance MRID Study Classification

Are data

Needed for 

Risk 

Assessment?

Comments

(Justification and Assumptions 

EPA will Make in Absence of 

Data)

850.4550

†

Aquatic Plant, 

cyanobacterium 

— TEP

None N/A Yes

Study should test up to highest 

application rate and/or aquatic EECs 

as defined in this problem 

formulation or previous risk 

assessments

TGAI = Technical Grade Active Ingredient

TEP = technical end product

* Algal toxicity tests are now under guideline OCSPP 850.4500 (formerly 850.5400)

† Cyanobacterium tests are now under guideline 850.4550 (formerly 850.5400)

Request for Sediment Toxicity Studies for Fenhexamid TGAI:

The use pattern, chemical properties, estimated exposure, and toxicity profile of fenhexamid

indicate need for chronic (life cycle) sediment toxicity tests to fully evaluate potential risks to 

benthic invertebrates. These sediment toxicity studies include two freshwater species (the 

midge, Chironomus dilutus and the amphipod, Hyalella azteca) and one saltwater species (the 

amphipod, Leptocheirus plumulosus). Multiple species are being recommended in order to 

account for differential sensitivity and exposure potential of benthic invertebrates to fenhexamid. 

This recommendation is being made because some KOC and log Kow values in submitted fate 

studies were above the thresholds of 1,000 and 3.0, respectively.

As an alternative to the conduct of three chronic (life cycle) sediment toxicity tests, EFED would 

also consider a tiered testing approach for sediment toxicity testing. In this approach, sediment 

toxicity testing would first be conducted with the aforementioned species using the 10-d 

(subchronic) sediment toxicity test guidelines (OSCPP 850.173525 and 850.174026). Then, 

pending a comparison of estimated environmental concentrations (EEC) in sediment and pore 

water with toxicity results from the 10-d sediment toxicity studies, the need for one or more 

chronic sediment toxicity studies would be determined. This tiered testing approach has the 

potential advantage of reducing the number of chronic (life cycle) studies that would be needed 

when results of the 10-d (subchronic) tests in conjunction with sediment EECs indicate chronic 

testing is not likely to alter risk assessment conclusions. In some cases, however, this tiered 

testing approach may result in the conduct of both a 10-d (subchronic) and a chronic (life cycle) 

study.

If the tiered test approach described above is not preferred, then chronic life-cycle sediment 

toxicity studies be carried out on the three preferred species, C. dilutus, H. azteca, and L. 

plumulosus. 

 

25 USEPA. 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/

Drafts/850-1735.pdf

26 USEPA. 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/

Drafts/850-1740.pdf
Page 37 of 71

8. Additional Information on Use

For risk assessment purposes, EFED will employ application scenarios that are expected to result 

in maximum exposure for each given use. Absence of information on the labels regarding 

maximum single application rates, application intervals, allowable annual maximum rates, or 

application methods will result in conservative assumptions as illustrated in the following 

examples:

If a label does not specify an application interval, an application interval of 3 days will be 

assumed.

It would be helpful for the registrant to provide supporting information on the following label 

uncertainties:

EPA registration number 66330-00035 states that for agricultural uses, applications may 

be made by ground only. Then in some sections of the label (almonds, pear, pistachios, 

stone fruit) it provides information for applications by air. EPA intends to engage the 

registrant to gain additional understanding on this label uncertainty.

Maximum single application rates are provided on a crop cycle basis. The maximum 

number of crop cycles per year for each crop would help to understand the maximum 

yearly application rate for each crop.

A maximum single application rate in lbs a.i./A for nursery and ornamentals, forest 

conifers, and non-bearing fruit trees and vines is not provided on some labels.

9. References

9.1. Literature Cited

Armitage, J. M., & Gobas, F. A. P. C. 2007. A terrestrial food-chain bioaccumulation model for 

POPs. Environmental Science and Technology, 41, 4019-4025.

Baris, R., Barrett, M., Bohaty, R. F. H., Echeverria, M., Villaneuva, P., Wolf, J., et al. 2013. 

Guidance for Using PRZM-GW in Drinking Water Exposure Assessments. December 11, 

2012. Environmental Fate and Effects Division. Office of Pesticide Programs. United 

States Environmental Protection Agency. Available at 

http://www.epa.gov/oppefed1/models/water/przm_gw/wqtt_przm_gw_guidance.htm

(Accessed January 22, 2013).

Bohaty, R. F. H., Eckel, W., White, K., & Young, D. F. 2012. Standard Operating Procedure for 

Using the NAFTA Guidance to Calculate Representative Half-life Values and 

Characterizing Pesticide Degradation. November 30, 2012. Environmental Fate and 

Effects Division. Office of Pesticide Programs. United States Environmental Protection 

Agency. Available at 

http://www.epa.gov/oppefed1/ecorisk_ders/degradation_kinetics/NAFTA_Degradation_

Kinetics.htm (Accessed February 8, 2013).

Costello, K. 2003.D293198. Section 18 for Fenhexamid to Control Gray Mold (Botrytis cinerea) 

on Kiwi in California. D293198. September 9, 2003. Environmental Fate and Effects 

Division. Office of Pesticide Programs. United States Environmental Protection 

Agency. 
Page 38 of 71

Cowles, J. 1999. Tier 1 Estimated Environmental Concentrations for Fenhexamid. February 1, 

1999. Environmental Fate and Effects Division. Office of Pesticide Programs. United 

States Environmental Protection Agency. 

Cowles, J., & Spatz, D. 1999.D244921+. EFED Risk Assessment for Section 3 Registration of 

Fenhexamid (Elevate TM 50 WDG). D244921, D244932, D249057, D250286, D253050 

& D254139. April 15, 1999. Environmental Fate and Effects Division. 

Cowles, J., & Steeger, T. 1999.D244921. Fenhexamid Section 3: Strawberries, Grapes, and 

Ornamentals. Environmental Fate and Ecolgoical Risk Assessment. A Joint Review with 

Health Canada. D244921. Environmental Fate and Effects Division. Office of Pesticide 

Programs. United States Environmental Protection Agency. 

Cowles, J., & Steeger, T. 1999.D257742. Section 18 for Fenhexamid to Control Gray Mold 

(Botrytis cinerea) on pears in California. D257742. July 27, 1999. Environmental Fate 

and Effects Division. Office of Pesticide Programs. United States Environmental 

Protection Agency. 

Felthousen, R. W. 2000.D259999. Section 3 Request for the use of Fenhexamid on Almonds and 

Stone Fruit. D259999. January 21, 2000. Environmental Fate and Effects Division. 

Office of Pesticide Programs. United States Environmental Protection Agency. 

Gobas, F. A. P. C., Kelly, B. C., & Arnot, J. A. 2003. Quantitative structure activity 

relationships for predicting the bioaccumulation of POPs in terrestrial food-webs. QSAR 

Comb. Sci, 22, 329-336.

Herndon, J. G. 1999. Fenhexamid. Results of the HED Metabolism Assessment Review 

Committee Meeting Held on 03/02/99. D253792. March 11, 1999. Health Effects 

Division. Office of Pesticide Programs. United States Environmental Protection 

Agency. 

NAFTA. 2012. Guidance for Evaluating and Calculating Degradation Kinetics in 

Environmental Media. December 2012. NAFTA Technical Working Group on 

Pesticides. Available at 

http://www.epa.gov/oppfead1/international/naftatwg/guidance/degradation-kin.pdf

(Accessed June 12, 2012).

Orton, F., Rosivatz, E., Scholze, M., & Kortenkamp, A. 2011. Widely used pesticides with 

previously unknown endocrine activity revealed as in Vitro Antiandrogens. 

Environmental Health Perspectives, 119(6), 794-800.

Phillips, T., & Costello, K. 2004.D297963. Risk Assessment for Proposed Use of Fenhexamid 

on Pome Fruit. D297963. May 1, 2004. Environmental Fate and Effects Division. 

Office of Pesticide Programs. United States Environmental Protection Agency. 

Phillips, T., & Costello, K. 2005.D312268+. Risk Assessment for Proposed Uses of Fenhexamid 

on Ginseng, Pomegranate, Non-Bell Pepper, and Cilantro. D312268, D312269 & 

D312270. May 25, 2005. Environmental Fate and Effects Division. Office of Pesticide 

Programs. United States Environmental Protection Agency. 

Sutton, C. A. 2002.D279884+. Section 3 Request for the Use of Fenhexamid on Blueberries, 

Caneberries, and Pistachios. D279884 & D279885. January 31, 2002. Environmental 

Fate and Effects Division. Office of Pesticide Programs. United States Environmental 

Protection Agency. 

Sutton, C. A. 2003.D274862. Fenhexamid: Response to Waiver Requests for Additional 

Aerobic Soil Metabolism Data and Additional Fish Bioaccumulation Data. D274862. 
Page 39 of 71

May 27, 2003. Environmental Fate and Effects Division. Office of Pesticide Programs. 

United States Environmental Protection Agency. 

Sutton, C. A. 2003.D285210+. Fenhexamid: Tier I Drinking Water EEC's for Use in the 

Human Health Risk Assessment. D285210, D287861 & D285215. May 13, 2003. 

Environmental Fate and Effects Division. Office of Pesticide Programs. United States 

Environmental Protection Agency. 

Sutton, C. A. 2007.D338651. Drinking Water Assessment for the IR-4 Petition for the Use of 

Fenhexamid on Asparagus. D338651. July 26, 2007. Environmental Fate and Effects 

Division. Office of Pesticide Programs. United States Environmental Protection Agency. 

Sutton, C. A., & Steeger, T. 2006.D326289+. Section 3 Registration of Fenhexamid for Use on 

Ginseng, Pomegranite, Cilantro, and Non-bell Peppers. D326289 & D326292. February 

16, 2006. Environmental Fate and Effects Division. Office of Pesticide Programs. 

United States Environmental Protection Agency. 

Sutton, C. A., & Steeger, T. 2006.D326293+. Section 3 Registration of Fenhexamid for Use on 

Pome Fruit Crop Group. D326293 & D326291. February 16, 2006. Environmental Fate 

and Effects Division. Office of Pesticide Programs. United States Environmental 

Protection Agency. 

Sutton, C. A., & Steeger, T. 2007.D340419. IR-4 Petition for Fenhexamid Use on Asparagus. 

D340419. June 14, 2007. Environmental Fate and Effects Division. Office of Pesticide 

Programs. United States Environmental Protection Agency. 

USEPA. 2000. National Pesticide Information Center. Captan Technical Fact Sheet. Oregon 

State University. United States Environmental Protection Agency. Available at 

http://npic.orst.edu/factsheets/captantech.pdf (Accessed February 13, 2013).

USEPA. 2008. White paper on Methods for Assessing Ecological Risks of Pesticides with 

Persistent, Bioaccumulative, and Toxic Characteristics. In Submitted to the FIFRA 

Scientific Advisory Panel for Review and Comment (Ed.), October 7, 2008. Washington, 

D.C. Available at 

http://www.epa.gov/scipoly/SAP/meetings/2008/october/sap_pbt_whitepaper_final_Oct_

7_08d.pdf (Accessed January 27, 2010).

USEPA. 2009a. ECOTOXicology Database, United States Environmental Protection Agency 

(USEPA). Available at http://cfpub.epa.gov/ecotox/ (Accessed June 19, 2009).

USEPA. 2009b. Guidance for Selecting Input Parameters in Modeling the Environmental Fate 

and Transport of Pesticides, Version 2.1. Available at 

http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm (Accessed 

November 12, 2010).

USEPA. 2009c. SAP Minutes No. 2009-01. A set of Scientific Issues Being Considered by the 

Environmental Protection Agency Regarding: Selected Issues Associated with the Risk 

Assessment Process for Pesticides with Persistent, Bioaccumulative, and Toxic 

Characteristics. October 28-31, 2008., January 29, 2009. Available at 

http://www.epa.gov/scipoly/sap/meetings/2008/102808_mtg.htm (Accessed July 9, 

2009).

USEPA. 2010a. Guidance for Reporting on the Environmental Fate and Transport of the 

Stressors of Concern in the Problem Formulation for Registration Review, Registration 

Review Risk Assessments, Listed Species Litigation Assessments, New Chemical Risk 

Assessments, and Other Relevant Risk Assessments, January 25, 2010. 
Page 40 of 71

USEPA. 2010b. Guidance for Reporting on the Environmental Fate and Transport of the 

Stressors of Concern in the Problem Formulation for Registration Review, Registration 

Review Risk Assessments, Listed Species Litigation Assessments, New Chemical Risk 

Assessments, and Other Relevant Risk Assessments. January 25, 2010. Environmental 

Fate and Effects Division, . Available at 

http://www.epa.gov/pesticides/science/efed/policy_guidance/team_authors/endangered_s

pecies_reregistration_workgroup/esa_reporting_fate.htm (Accessed July 5, 2012).

USEPA. 2011. Estimation Program Interface (EPI) Suite: United States Environmental 

Protection Agency. Available at http://www.epa.gov/oppt/exposure/pubs/episuite.htm

(Accessed January 25, 2013).

USEPA. 2012. Office of Pesticide Programs Chemical Search. Office of Pesticide Programs. 

United States Environmental Protection Agency. Available at 

http://iaspub.epa.gov/apex/pesticides/f?p=chemicalsearch:1 (Accessed July 5, 2012).

USEPA, & Canada, H. 2011. Guidance for Evaluating and Calculating Degradation Kinetics in 

Environmental Media. December 21, 2011. NAFTA Technical Working Group on 

Pesticides. Available at 

http://www.epa.gov/oppfead1/international/naftatwg/guidance/degradation-kin.pdf

(Accessed February 6, 2013).

Vonk, J. W. 2000. A steam distillation/extraction method for analysis of soil-bound residues of 

chlorinated anilines and chloroaniline-containing pesticides. In J. Comejo & P. Jamet 

(Eds.), Pesticide/soil Interactions (pp. 249-254). Paris: Institut National De La Recherche 

Agronomique. 

9.2. Studies Submitted by the Registrant

63-8 Solubility

44346718 Krohn, J. (1993) Solubility of KBR 2738 in Representative Organic Solvents: 

Lab Project Number: PC 1119: TMN-018G: Q 504 0517. Unpublished study 

prepared by Bayer Ag. 10 p. 

44346719 Krohn, J. (1996) Water Solubility of KBR 2738 as a Function of pH: Lab 

Project Number: PC 1411: TMN-018H: 14 660 0896. Unpublished study 

prepared by Bayer Ag. 14 p. 

63-9 Vapor Pressure

44346720 Krohn, J. (1995) Vapor Pressure Curve of KBR 2738: Lab Project Number: PC 

1064: TMN-018J: 14 215 0857. Unpublished study prepared by Bayer Ag. 18 p. 

63-10 Dissociation Constant

44346714 Stupp, H. (1995) Dissociation Constant and pH of KBR 2738: Lab Project 

Number: PC 939: TMN-018K: 15 550 202. Unpublished study prepared by 

Bayer Ag. 11 p. 

63-11 Oct/Water partition Coef.

44346717 Krohn, J. (1995) Partition Coefficient of KBR 2738 in Octanol-Water as a 

Function of pH: Lab Project Number: PC 1096: TMN-018L: 14 447 0884. 

Unpublished study prepared by Bayer Ag. 14 p. 

63-13 Stability
Page 41 of 71

44346707 Eberz, A.; Berg, G. (1995) Thermal Stability of the Active Ingredient KBR 

2738 (950821ELB04): Lab Project Number: PC 1065: TMN-018M: 95/10391. 

Unpublished study prepared by Bayer Ag. 16 p. 

44346708 Lunkenheimer, W. (1997) KBR 2738 Technical: Stability to Metals and Metal 

Ions: Lab Project Number: STATEMENT: TMN-0018MM. Unpublished study 

prepared by Bayer Ag. 4 p. 

161-1 Hydrolysis

44346725 Brumhard, B. (1995) Hydrolysis of KBR 2738 in Sterile Aqueous Buffer 

Solutions: Lab Project Number: PF 4098: TMN-014H: M 111 0568-2. 

Unpublished study prepared by Bayer Ag. 35 p. 

44346761 Reigner, K. (1996) Aqueous Hydrolysis of KBR 2738 Under Conditions of 

Processing Studies: Lab Project Number: PF-4166: TMN-014M: M 177 0800-3. 

Unpublished study prepared by Bayer Ag. 31 p. 

161-2 Photodegradation-water

44346726 Brumhard, B.; Bornatsch, W. (1996) Photolysis of KBR 2738 in Aqueous 

Solutions: Lab Project Number: 4194: TMN-014J: M 112 0569-4. Unpublished 

study prepared by Bayer Ag. 113 p. OPPTS 835.2240.

44346732 Brumhard, B. (1996) Photodegradation of KBR 2738 in Natural Water: Lab 

Project Number: PF 4182: TMN-0141: M 112 0731-5. Unpublished study 

prepared by Bayer Ag. 56 p. 

161-3 Photodegradation-soil

44346728

Brumhard, B. (1996) Photolysis of KBR 2738 on Soil Surfaces: Lab Project 

Number: PF-4167: TMN-014A: M 113 0642-7. Unpublished study prepared by 

Bayer Ag. 67 p. 

162-1 Aerobic soil metabolism

44346729 Brumhard, B.; Bornatsch, W. (1997) Aerobic Degradation and Metabolism of 

KBR 2738 in Soil (Including Amendment): Lab Project Number: PF-4195: 

TMN-014BB: M 125 0550-8. Unpublished study prepared by Bayer Ag. 117 p. 

44346730 Brumhard, B. (1997) Aerobic Degradation of (Carboxamide-(carbon 14))KBR 

2738 in Soil: Lab Project Number: PF 4239: TMN-014B-1: M 999 0844-3. 

Unpublished study prepared by Bayer Ag. 50 p.

162-3 Anaerobic aquatic metab.

44346731 Hennebole, J.; Bornatsch, W. (1997) Anaerobic Aquatic (Soil) Metabolism of 

KBR 2738: Lab Project Number: PF-4203: MR 17/97: TMN-014EE. 

Unpublished study prepared by Bayer Ag. 72 p. 

162-4 Aerobic aquatic metab.

44518701 Brumhard, B.; Bornatsch, W. (1997) Degradation and Metabolism of KBR 2738 

in the System Water/Sediment: Lab Project Number: PF-4202: TMN-014JJ: M 

151 0564-2. Unpublished study prepared by Bayer Ag. 114. 

163-1 Leach/adsorp/desorption

44346722 Brumhard, B. (1996) Adsorption/Desorption of KBR 2738 on Different Soils: 

Lab Project Number: PF-4136: TMN-014AA: M 313 0613-5. Unpublished 

study prepared by Bayer Ag. 54 p. 
Page 42 of 71

44346723 Fent, G. (1997) Adsorption/Desorption of (Benzoxazol-2-(carbon 14))WAK

7004 on Four Different Soils: (Final Report): Lab Project Number: FM762: 

TMN-014FF: BAY21. Unpublished study prepared by Staatliche Lehr-Und 

Forschungsanstalt fuer Landwirtschaft. 40 p. 

164-1 Terrestrial field dissipation

44346724 Obrist, J. (1997) Mobility and Degradation of (carbon 14)-TM-402 as 

Determined Using Field Lysimeters: Lab Project Number: 96568: TMN014CCC: 402USATD96.001. Unpublished study prepared by Plant Sciences, 

Inc. and ABC Laboratories California. 197 p. 

44346734 Montonaga, K.; Morishima, N. (1996) Degradation of KBR 2738 in Upland 

Soil: Lab Project Number: NR 96050/ESR: TMN-014CC: 96032/ESR. 

Unpublished study prepared by Nihon Bayer Agrochem K. K. 30 p. 

44580302 Vaughn, F.; Parnell, J. (1998) Dissipation of TM-402 on Bare Soil in Canada 

(To Support Registration for Use on Grapes): Lab Project Number: KBR-SOILGRAPE: 97TOM02. Unpublished study prepared by Enviro-Test Laboratories. 

158 p. 

44580303 Vaughn, F.; Parnell, J. (1998) Dissipation of TM-402 on Bare Soil in Canada 

(To Support Registration for Use on Strawberries): Lab Project Number: KBRSOIL-STBRY: 97TOM01. Unpublished study prepared by Enviro-Test 

Laboratories. 160 p. 

45447501 Vaughn, F. (2000) Dissipation of TM-402 on Bare Soil and in Strawberry 

Culture in Canada: Lab Project Number: 99TOM01: TMN-014B-4: 1732-A. 

Unpublished study prepared by Analytical Development Corporation. 837 p. 

165-1 Confined rotational crop

44346767 Reiner, H. (1997) Confined Rotational Crop Study with KBR 2738: Lab Project 

Number: PF-4240: TMN-014DD: M 13007146. Unpublished study prepared by 

Bayer Ag. 113 p. 

165-4 Bioaccumulation in fish

44346746 Dorgerloh, M. (1996) (Carbon 14)KBR 2738--Uptake, Depuration and 

Bioconcentration in Bluegill (Lepomis macrochirus) Under Flow-Through 

Conditions: Lab Project Number: DOM 95086: TMN-001M: E 2440990-8. 

Unpublished study prepared by Bayer Ag. 62 p. 

44346747 Printz, H. (1997) (Phenyl-UL-(carbon 14))KBR 2738: Identification of 

Radioactive Residues in Bluegill Sunfish (Lepomis macrochirus): Lab Project 

Number: PF-4204: TMN-014K: M 289 0788-2. Unpublished study prepared by 

Bayer Ag. 77 p. 

9.3.

71-1 Avian Single Dose Oral Toxicity

44346750

Grau, R. (1995) KBR 2738 Technical: Acute Oral Toxicity to Bobwhite 

Quail: Lab Project Number: VB-038: TMN-001Q: E2920907-9. Unpublished 

study prepared by Bayer Ag. 26 p. 

71-2 Avian Dietary Toxicity

44346751

Grau, R. (1995) KBR 2738 Technical: 5-Day Dietary LC50 to Bobwhite 

Quail: Lab Project Number: VB-042: TMN-001P: E 295 0875-6. Unpublished 

study prepared by Bayer Ag. 34 p.
Page 43 of 71

44346752

Grau, R. (1995) KBR 2738 Technical: 5-Day Dietary LC50 to Mallard Duck: 

Lab Project Number: VE-008: TMN-001R: E2970874-7. Unpublished study 

prepared by Bayer Ag. 35 p.

71-4 Avian Reproduction

44346753 Schmuck, R. (1997) Effects of a Subchronic Dietary Exposure of KBR 2738 

(Technical) on Bobwhite Quail Including Effects on Reproduction and Health 

(Including Amendment): Lab Project Number: SXR/REP 06: TMN-001N: E 

293 1027-9. Unpublished study prepared by Bayer Ag. 134 p. 

72-1 Acute Toxicity to Freshwater Fish

44346741 Dorgerloh, M. (1995) KBR 2738 Technical--Acute Toxicity (96 Hours) to 

Bluegill (Lepomis macrochirus) Under Flow-Through Conditions: Lab 

Project Number: DOM 95002: TMN-001D: E 252 0916-5. Unpublished study 

prepared by Bayer Ag. 44 p. 

44346742 Dorgerloh, M. (1995) KBR 2738 Technical--Acute Toxicity (96 Hours) to 

Rainbow Trout (Oncorhynchus mykiss) Under Flow-Through Conditions: 

Lab Project Number: DOM 95001: TMN-001E: E 250 0915-2. Unpublished 

study prepared by Bayer Ag. 46 p. 

44523605 Dorgerloh, M. (1996) KBR 2738 WG 50--Acute Toxicity (96 Hours) to 

Rainbow Trout (Oncorhynchus mykiss) in a Semi-Static Test: Lab Project 

Number: DOM 95042: TMN-001EE: E 281 0995-4. Unpublished study 

prepared by Bayer Ag. 36 p. 

72-3 Acute Toxicity to Estuarine/Marine Organisms

44346740 Roberts, C.; Swigert, J. (1996) TM-402: A 96-Hour Flow-Through Acute 

Toxicity Test with the Saltwater Mysid (Mysidopsis bahia): Lab Project 

Number: 443A-101: TMN-001A. Unpublished study prepared by Wildlife 

International Ltd. 68 p. 

44346743 Roberts, C.; Swigert, J. (1996) TM-402: A 96-Hour Flow Through Acute 

Toxicity Test with the Sheepshead Minnow (Cyprinodon variegatus): Lab 

Project Number: 443A-102: TMN-001B. Unpublished study prepared by 

Wildlife International Ltd. 68 p. 

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

44346744

Heimbach, F. (1996) Influence of KBR 2738 (Tech.) on the Reproduction 

Rate of Water Fleas: Lab Project Number: HBF/RDM 56: TMN-001I: E 321 

1038-8. Unpublished study prepared by Bayer Ag. 89 p. 

44346745 Dorgerloh, M. (1996) KBR 2738: Early Life Stage Toxicity to Rainbow Trout 

(Oncorhynchus mykiss) Under Flow-Through Conditions: Lab Project 

Number: DOM 96050: TMN-001G: E 2841013-9. Unpublished study 

prepared by Bayer Ag. 101 p. 

44366507 Heimbach, F. (1995) Acute Toxicity of KBR 2738 (Tech.) to Water Fleas 

(Daphnia magna): Lab Project Number: HBF/DM 139: TMN-001F: E 320 

0913-8. Unpublished study prepared by Bayer Ag, Crop Protection. 37 p. 

81-1 Acute oral toxicity in rats

44345908 Kroetlinger, F. (1995) KBR 2738 50 WG 04258/0214: Study for Acute Oral 

Toxicity in Rats: Lab Project Number: 24227: TMN-025B: T 4059136. 

Unpublished study prepared by Bayer Ag Germany. 32 p. 
Page 44 of 71

44346769 Bomann, W. (1991) KBR 2738: Study for Acute Oral Toxicity in Rats: Lab 

Project Number: 20640: TMN-028: T 3037355. Unpublished study prepared 

by Bayer Ag. 38 p. 

81-2 Acute dermal toxicity in rabbits or rats

44345909 Kroetlinger, F. (1995) KBR 2738 50 WG 04258/0214: Study for Acute 

Dermal Toxicity in Rats: Lab Project Number: 24183: TMN-025C: T 

5059137. Unpublished study prepared by Bayer Ag Germany. 31 p.

44346770 Bomann, W. (1991) KBR 2738: Study for Acute Dermal Toxicity in Rats: 

Lab Project Number: 20639: TMN-026: T 4037356. Unpublished study 

prepared by Bayer Ag. 37 p. 

83-4 2-generation repro.-rat

44346802 Eigenberg, D.; Hoss, H. (1996) Pilot Study to Establish Dose Levels for a 

Two-Generation Reproduction Study in Rats Using Technical Grade KBR 

2738 Administered via the Diet: Lab Project Number: 107460: 8007: TMN030J. Unpublished study prepared by Bayer Corp. 256 p. 

44346803 Eigenberg, D.; Hastings, T. (1997) A Two Generation Dietary Reproduction 

Study in Rats Using Technical Grade KBR 2738 (Including Amendment): 

Lab Project Number: 107461: 8008: TMN-030K. Unpublished study prepared 

by Bayer Corp. 1378 p. 

122-2 Aquatic plant growth

44518705 Anderson, J. (1996) Influence of KBR 2738 on the Growth of the Green Alga, 

Scenedesmus subspicatus: Lab Project Number: AJO/133595: TMN-001J: E 

323 0948-9. Unpublished study prepared by Bayer Ag. 26 p. 

44518706 Anderson, J. (1995) Influence of KBR 2738 on the Growth of the Green Alga, 

Selenastrum capricornutum: Lab Project Number: AJO/128695: TMN-001K: 

E3230926-5. Unpublished study prepared by Bayer Ag. 41 p. 

44523610 Anderson, J. (1995) Influence of KBR 2738 WG 50 on the Growth of the 

Green Alga, Selenastrum capricornutum: Lab Project Number: AJO/128795: 

TMN-001L: E 323 0925 4. Unpublished study prepared by Bayer Ag. 40 p. 

44731104 Smith, C. (1998) Fenhexamid Technical: Aquatic Vascular Plant Data 

Summary: Lab Project Number: KBR-9.8.1-SUM. Unpublished study 

prepared by Bayer AG. 5 p. 

44731105 Palmer, S.; Krueger, H. (1998) Fenhexamid Technical (TM-402): A 14-Day 

Toxicity Test with Duckweed (Lemna gibba G3): Lab Project Number: 

443A103. Unpublished study prepared by Wildlife International LTD. 46 p. 

123-2 Aquatic plant growth

44518705 Anderson, J. (1996) Influence of KBR 2738 on the Growth of the Green Alga, 

Scenedesmus subspicatus: Lab Project Number: AJO/133595: TMN-001J: E 

323 0948-9. Unpublished study prepared by Bayer Ag. 26 p. 

44518706 Anderson, J. (1995) Influence of KBR 2738 on the Growth of the Green Alga, 

Selenastrum capricornutum: Lab Project Number: AJO/128695: TMN-001K: 

E3230926-5. Unpublished study prepared by Bayer Ag. 41 p. 

44523610 Anderson, J. (1995) Influence of KBR 2738 WG 50 on the Growth of the 

Green Alga, Selenastrum capricornutum: Lab Project Number: AJO/128795: 

TMN-001L: E 323 0925 4. Unpublished study prepared by Bayer Ag. 40 p. 

141-1 Honey bee acute contact
Page 45 of 71

44346755 Winkler, R. (1995) Testing Toxicity to Honeybee--Apis mellifera L. 

(Laboratory) According to EPPO Guideline No. 170: KBR 2738 (Technical): 

Lab Project Number: 95 10 48 058: TMN-017A: 0097201. Unpublished study 

prepared by Biochem Gmbh Karlsruhe. 23 p. 

141-2 Honey bee residue on foliage

44346755 Winkler, R. (1995) Testing Toxicity to Honeybee--Apis mellifera L. 

(Laboratory) According to EPPO Guideline No. 170: KBR 2738 (Technical): 

Lab Project Number: 95 10 48 058: TMN-017A: 0097201. Unpublished study 

prepared by Biochem Gmbh Karlsruhe. 23 p. 

143-1 Toxicity to Predator and Parasite Insects

44523608 Mead-Briggs, M. (1995) A Laboratory Evaluation of the Side-Effects of the 

Fungicide KBR 2738 WG 50 on the Parasitic Wasp Aphidius rhopalosiphi: 

Lab Project Number: BAY-95-1: TMN-017D. Unpublished study prepared by 

University of Southampton. 19 p. 

870.1100 Acute oral toxicity

45829702 Mezin, L.; Kuhn, J. (2002) CaptEvate 68 WDG: Acute Oral and Dermal 

Toxicity in Rats and Dermal Irritation in Rabbits: Lab Project Number: TMN0070: 7039-02: 7040-02. Unpublished study prepared by Stillmeadow, Inc. 

and Arvesta Corporation. 43 p.

870.1200 Acute dermal toxicity

45829702 Mezin, L.; Kuhn, J. (2002) CaptEvate 68 WDG: Acute Oral and Dermal 

Toxicity in Rats and Dermal Irritation in Rabbits: Lab Project Number: TMN0070: 7039-02: 7040-02. Unpublished study prepared by Stillmeadow, Inc. 

and Arvesta Corporation. 43 p.

870.1300 Acute inhalation toxicity

45829703

Carter, L. (2002) Acute Inhalation Toxicity Study in Rats: Captan 80 WP: 

Final Report: Lab Project Number: 7038-02. Unpublished study prepared by 

Stillmeadow, Inc. 27 p.

870.2500 Acute dermal irritation

45829702 Mezin, L.; Kuhn, J. (2002) CaptEvate 68 WDG: Acute Oral and Dermal 

Toxicity in Rats and Dermal Irritation in Rabbits: Lab Project Number: TMN0070: 7039-02: 7040-02. Unpublished study prepared by Stillmeadow, Inc. 

and Arvesta Corporation. 43 p.
Page 46 of 71

Appendix A. Supplemental Environmental Fate Information

Table A1. Structures of Fenhexamid and Its Environmental Transformation Products. 

Code Name/ Synonym/

Chemical Name/ Formula/MW/ SMILES Chemical Structure

Fenhexamid, KBR 2738, TM-402, KBA 2738, FEX

IUPAC: 2',3'-dichloro-4'-hydroxy-1-

methylcyclohexanecarboxanilide

CAS: N-(2,3-dichloro-4-hydroxyphenyl)-1-

methylcyclohexanecarboxamide

CAS No.: 126833-17-8

Formula: C14H17Cl2NO2

MW: 302.2 g/mole

SMILES: O=C(Nc1ccc(O)c(Cl)c1Cl)C2(C)CCCCC2

WAK 7004, BB J 99-3

IUPAC: 7-Chloro-2-(1-methylcyclohexyl)-1,3-

benzoxazol-6-ol

Formula: C14H16ClNO

MW: 265.74 g/mol

SMILES:

C1=CC(=C(C3=C1N=C(C2(CCCCC2)C)O3)Cl)O[H]

Log KOC=3.9 to 4.9

M1 and M2

SMILES:

(a)

O=C(NC1=C(C(=C(C(=C1O)O)O)O)O)C2(C)CCCCC2

(b)

O=C(NC1=CC=C(C(=C1O)O)O)C2(C)CCCCC2.CO

(c) 

O=C(NC1=C(C(C(=C(C1=O)O)O)=O)O)C2(C)CCCCC2

(d) succinic acid

CAS Number 110-15-6

SMILES: C(CCC(O)=O)(O)=O

12 compounds not readily separated, see Page 33 of MRID 

444346726, 4 structures for single components were provided

(a)

(b)

(c)
Page 47 of 71

Code Name/ Synonym/

Chemical Name/ Formula/MW/ SMILES Chemical Structure

(d)

M4, BBJ98-11, Trishydroxyl-KBR

SMILES:

O=C(N(C1=CCC(C=C1)O[H])[H])C2(C)CCCCC2.O.O

C-C Biphenyl, BBJ98-8

SMILES:O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C

2(C)CCCCC2.O=C(N(C3=C(C(=C(C=C3)O[H])Cl)Cl)[

H])C4(C)CCCCC4.CC

ZE056401, suflonic ester of parent, sulfonic ester Fex

SMILES: 

O=C(NC1=C(C(=C(C=C1)O[S](O)(O)O)Cl)Cl)C2(C)CC

CCC2

M7-B

N-acetyl-2,3-dichloro-p-aminophenol (proposed)

SMILES: O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C
Page 48 of 71

Code Name/ Synonym/

Chemical Name/ Formula/MW/ SMILES Chemical Structure

Ketoisomers (proposed), M7-C, M7-F, M7-H-M7-K

SMILES: 

O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C2(C)CCCC

C2.=O

KBR 7133, M7-I, OH-KBR

SMILES:

O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C2(C)C(CC

CC2)O[H]

KBR7115, M7-G, OH-KBR

SMILES:

O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C2(C)CC(C

CC2)O

KBR6720, KBR6798, M7-E

OH-KBR

SMILES: 

O=C(N(C1=C(C(=C(C=C1)O[H])Cl)Cl)[H])C2(C)CCC(

CC2)O

BNF 5537C

MW: 178.02 g/mole

SMILES: C1=CC(=C(C(=C1N)Cl)Cl)O 

Log KOW=1.53

Water Solubility=2813.6 mg/L

KOC=246.7 (MCI method) and 82.53 (KOW method)

KBR 2931, WAK 6919

MW: g/mol

SMILES:

C1=C(C(=CC=C1N(C(C2(CCCCC2)C)=O)[H])O[H])Cl

CH3-phenyl FEX, KBR 3596, BBJ 98-7

SMILES:

C1(=C(C(=CC=C1N(C(C2(CCCCC2)C)=O)[H])OC)Cl)

Cl
Page 49 of 71

Code Name/ Synonym/

Chemical Name/ Formula/MW/ SMILES Chemical Structure

KBR3954

SMILES:

C1(=C(C(=CC=C1N(C(C2(CCCCC2)C)=O)[H])O)Cl)Cl

KBR5613, WAK6920, M9

SMILES:

C1(=CC(=CC=C1N(C(C2(CCCCC2)C)=O)[H])O)Cl

KBR6259, WAK 6918

SMILES:

C1=CC(=CC=C1N(C(C2(CCCCC2)C)=O)[H])O[H]

LSH 2344

SMILES: C1=C(C(=C(C(=C1)O)Cl)Cl)O

M5, BBJ98-12

SMILES: 

O=C(N(C1=CC(C(C=C1)=O)=O)[H])C2(C)CCCCC2.O

BBJ 98-11, deschloro-[C-O-C]biphenyl Dimer

Trimer 1, BBJ 98-9
Page 50 of 71

Code Name/ Synonym/

Chemical Name/ Formula/MW/ SMILES Chemical Structure

Trimer 2, BBJ 98-12

BBJ 98-13

*SMILES:

C1=CC(=C(C(=C1NC(C2(CCCCC2)C)=O)OC3=C(C(=

C(C=C3)NC(C4(CCCCC4)C)=O)Cl)Cl)Cl)O

M3 Structure not provided

M10 Structre not provided

Abbreviations MW =molecular weight; IUPAC: International Union of Pure and Applied Chemistry name; 

SMILES: Simplified Molecular-input Line-entry System

Table A2. Summary of Maximum Degradate Amounts in Environmental Fate Studies of 

Fenhexamidb

Compoundc

Max Degradate % of AR Associated with Compound (Time of Peak)

Amount Detected at Final Sampling Interval in Corresponding Study Max Conc in 

TFD 

Hydrolysis Aqueous (μg/kg soil)

Photolysis

Soil 

Photolysis

Aerobic 

Soil

Anaerobic 

Soil

Aerobic 

Aquatic

WAK 7004 --

24 (1 d)

nd (15 d) -- -- -- -- 28.0

M4 --

26 (1 d)

nd (15 d) -- -- 2.4 (360 d)a NA NA

C-C biphenyl 

dimer/ 

BBJ 98-8

-- --

14 (1 d)

2.4 (18 d)

6 (1 d)

1 (100 d) NA

M1 Mixture -- 27 (15 d)a -- -- -- -- NA

M2 Mixture -- 17 (15 d)a -- -- -- -- NA

M7 Mixture -- -- -- --

9 (120 d)

4 (360 d) -- NA

M3 -- -- -- --

4.4 (120 d)

<0.1 (360 d) -- NA
Page 51 of 71

Compoundc

Max Degradate % of AR Associated with Compound (Time of Peak)

Amount Detected at Final Sampling Interval in Corresponding Study Max Conc in 

TFD 

Hydrolysis Aqueous (μg/kg soil)

Photolysis

Soil 

Photolysis

Aerobic 

Soil

Anaerobic 

Soil

Aerobic 

Aquatic

Sulfonic Ester FEX/ 

ZE056401 -- -- -- -- --

7.4 (7 d)

0.15 (100 d) NA

M9, KBR 5613 --

6 (5 h)

nd (15 d) -- -- 5 (365 d)a -- NA

KBR 2931 --

7 (0.5 h)

nd (24 h) -- -- -- -- NA

M10 -- -- -- --

3.2 (251 d)

2.3 (365 d) -- NA

CH3-phenyl FEX/ 

KBR 3596/ BBJ 

98-7

-- --

3 (0.25 d)

2 (18 d)

5 (3 d)

0.3 (365 d) -- -- NA

Trimer 1/ 

BBJ 98-9

-- --

4 (0.25 d)

1 (18 d) -- -- -- NA

COC Biphenyl 

Dimer/ 

BBJ 98-11 -- --

6 (0 d)

0.5 (18 d)

4 (1 d)

0.5 (100 d) -- -- NA

Trimer 2/ 

BBJ 98-12 -- --

5 (0.25 d)

1 (18 d)

2 (0 d)

1 (365 d) -- -- NA

KBR 6259 --

3 (2 h)

nd (24 hr) -- -- -- -- NA

NA=not analyzed; h=hours; d=days; Max=maximum; Conc=concentration; TFD=terrestrial field dissipation study; 

nd=not detected. Degradate structures are available in Appendix A and Figure 2.

a Peak at final sampling interval in some studies

b See Appendix A for more information on source of information in this table.

c The structure of M3 and M10 are unknown.

Table A3. Maximum amount of applied radioactivity present as a specified compound in

environmental fate studies submitted on fenhexamid.1,2,3

Compound Study Type Max %AR 

(Sampling Interval)

Final %AR 

(Sampling 

Interval)

Comment MRID

Parent

Hydrolysis

Not Applicable

100.1 (35 d) pH 5 44346725

100.1 (35 d) pH 7 44346725

99.0 (35 d) pH 9 44346725

Aqueous Photolysis nd (15 d) sterile water, phe 44346726

nd (24 h) natural water, phe 44346732

Soil Photolysis 1.1 (18 d) sandy loam, phe 44346728

Aerobic Soil

1.0 (365 d) Howe soil U.S., phe 44346729

1.0 (100 d) BBA 2.1 soil, phe 44346729

2.3 (100 d) BBA 2.2 soil, phe 44346729
Page 52 of 71

Compound Study Type Max %AR 

(Sampling Interval)

Final %AR 

(Sampling 

Interval)

Comment MRID

1.0 (100 d) Laacher Hof Soil, 

phe 44346729

0.6 (100 d) Howe soil U.S., phe 44346730

0.8 (100 d) Laacher Hof Soil, 

carb 44346730

Aerobic Aquatic

6.82 (100 d) Lake Honniger, phe 44518701

1.14 (100 d) Lake Stanley, phe 44518701

Anaerobic Soil 3.8 (360 d) Howe soil, phe 44346731

Terrestrial Field 

Dissipation

0.21 mg/kg-soil (0 d) <0.01 mg/kgsoil (120 d) Ontario, bare 44580303

0.762 mg/kg-soil (0 d)

0.303 mg/kg-soil 

(120 d) California, bare 44346724

3.292 mg/kg-soil (0 d) 0.089 mg/kg-soil 

(63 d)

British Columbia, 

bare 45447501

2.902 mg/kg-soil (0 d) 0.081 mg/kg-soil 

(63 d)

British Columbia, 

strawberrry 45447501

0.03 mg/kg-soil (0 d) <0.01 mg/kgsoil (60 d) Ontario, bare 44580302

Major Degradates

WAK 7004

Aqueous Photolysis

23.6 (1 h) nd (15 d) water, phe 44346726

23.5 (0.5 h) nd (24 h) natural water, phe 44346732

Terrestrial Field 

Dissipation

0.0280 mg/kg-soil <LOQ British Columbia, 

bare 45447501

0.0206 mg/kg-soil <LOQ British Columbia, 

strawberrry 45447501

M4

Aqueous Photolysis ~26.3 (1 d)* nd (15 d) water, phe 44346726

Anaerobic Soil 2.4 (360 d) 2.4 (360 d) howe soil, phe 44346731

BBJ-98-8

Soil Photolysis 13.8 (0.25,1 d) 2.4 (18 d) sandy loam, phe 44346728

Aerobic Soil

4.7 (0 d) 0.5 (365 d) Howe soil U.S., phe 44346729

5.8 (1 d) 1.2 (100 d) BBA 2.1 soil, phe 44346729

1.5 (3 d) 0.6 (100 d) BBA 2.2 soil, phe 44346729

2.4 (1 d) 0.6 (100 d) Laacher Hof Soil, 

phe

44346729

2.9 (2 d) 0.6 (100 d) Howe soil U.S., carb 44346730

1.0 (2 d) 0.2 (100 d) Laacher Hof Soil, 

carb

44346730

Minor Degradates

M1(mixture)4

Aqueous Photolysis 27.3 (15 d) 27.3 (15 d) water, phe 44346726

M2(mixture)4 Aqueous Photolysis 16.7 (15 d) 16.7 (15 d) water, phe 44346726

M7 (mixture) Anaerobic Soil 9.3 (120 d) 4.1 (360 d) Howe soil, phe 44346731

M3 Anaerobic Soil 4.4 (120 d) <0.1 (360 d) Howe soil, phe

ZE056401 Aerobic Aquatic

0.89 (14 d) 0.18 (100 d) Lake Honniger, phe 44518701

7.4 (7d) 0.15 (100 d) Lake Stanley, phe 44518701

M9, KBR 5613

Anaerobic Soil 4.9 (365 d) 4.9 (365 d) Howe soil, phe 44346731

Aqueous Photolysis 5.9 (5 h) nd (15 d) sterile water, phe 

phenyAqueous

44346726
Page 53 of 71

Compound Study Type Max %AR 

(Sampling Interval)

Final %AR 

(Sampling 

Interval)

Comment MRID

4.4 (1 h) nd (24 h) natural water, phe 44346732

M10 Anaeroibic Soil 3.2 (251 d) 2.3 (365 d) Howe soil, phe 44346731

KBR 3596, 

BBJ 98-7

Soil Photolysis 3.4 (0.25 days) 1.7 (18 days) sandy loam, phe 44346728

Aerobic Soil

2.8 (0 d) 0.3 (365 d) Howe soil U.S., phe 44346729

1.7 (1 d) 0.5 (100 d) BBA 2.1 soil, phe 44346729

5.1 (3 d) 1.0 (100 d) BBA 2.2 soil, phe 44346729

3.7 (1 d) 0.4 (100 d) Laacher Hof Soil, 

phe 44346729

2.2 (0 d) 0.5 (100 d) Howe soil U.S., carb 44346730

4.5 (2 d) 0.5 (100 d) Laacher Hof Soil, 

carb 44346730

BBJ 98-9

Soil Photolysis 4.2 (0.25 days) 1.3 (18 days) sandy loam, phe 44346728

Aerobic Soil

3.8 (0 d) 1.6 (365 d) Howe soil U.S., phe 44346729

5.5 (1 d) 2.1 (100 d) BBA 2.1 soil, phe 44346729

1.2 (3 d) 0.7 (100 d) BBA 2.2 soil, phe 44346729

1.7 (1 d) 1.0 (100 d) Laacher Hof Soil, 

phe 44346729

3.4 (0 d) 1.1 (100 d) Howe soil U.S., phe 44346730

1.1 (8 d) 0.3 (100 d) Laacher Hof Soil, 

carb 44346730

BBJ98-11

Soil Photolysis 5.5 (0 d) 0.5 (18 d) sandy loam, phe 44346728

Aerobic Soil

2.9 (0 d) nd (365 d) Howe soil U.S., phe 44346729

3.7 (1 d) 0.5 (100 d) BBA 2.1 soil, phe 44346729

2.9 (3 d) 2.3 (100 d) BBA 2.2 soil, phe 44346729

2.7 (1 d) 0.3 (100 d) Laacher Hof soil, phe 44346729

2.2 (0 d) 0.1 (100 d) Howe soil U.S., phe 44346730

2.0 (2 d) 0.1 (100 d) Laacher Hof soil, 

carb 44346730

BBJ 98-12

Soil Photolysis 4.5 (0.25 days) 0.9 (18 days) sandy loam, phe 44346728

Aerobic Soil

2.4 (0 d) nd (365 d) Howe soil U.S., phe 44346729

2.0 (1 d) nd (100 d) BBA 2.1 soil, phe 44346729

1.2 (3 d) 0.6 (100 d) BBA 2.2 soil, phe 44346729

1.2 (1 d) 0.6 (100 d) Laacher Hof soil, phe 44346729

1.7 (0 d) 0.5 (100 d) Howe soil U.S., carb 44346730

1.9 (2 d) 0.5 (100 d) Laacher Hof Soil, 

carb 44346730

KBR 5613 Aqueous Photolysis

5.9 (5 h) nd (15 d) sterile water, phe 

phenyAqueous

44346726

4.4 (1 h) nd (24 h) natural water, phe 44346732

KBR 2931 Aqueous Photolysis

4.4 (3 h) nd (15 d) water, phe 44346726

6.9 (0.5 h) nd (24 hs) natural water, phe 44346732

KBR 6259 Aqueous Photolysis 3.2 (2 h) nd (24 h) natural water, phe 44346732

Other Degradates

CO2 Aqueous Photolysis 39.3 (15 h) 39.3 (15 d) sterile water, phe 44346726
Page 54 of 71

Compound Study Type Max %AR 

(Sampling Interval)

Final %AR 

(Sampling 

Interval)

Comment MRID

28.2 (24 hr) 28.2 (24 h) natural water, phe 44346732

Soil Photolysis 8.7 (18 d)M1 8.7 (18 d) sandy loam, phe 44346728

Aerobic Soil

30 (365 d) 30 (365 d) Howe soil U.S., phe 44346729

20.6 (100 d) 20.6 (100 d) BBA 2.1 soil, phe 44346729

19.9 (100 d) 19.7 (100 d) BBA 2.2 soil, phe 44346729

17.8 (1 d) 17.8 (100 d) Laacher Hof soil, phe 44346729

36 (100 d) 36 (100 d) Howe soil U.S., carb 44346730

40 (100 d) 40 (100 d) Laacher Hof soil, 

carb 44346730

Aerobic Aquatic

4.7 (100 d) 4.7 (100 d) Lake Honniger, phe 44518701

12.8 (100 d) 12.8 (100 d) Lake Stanley, phe 44518701

Unidentified 

Compound(s)3

Aqueous Photolysis 13.5 (5 h)+ nd (15 d)+ sterile water, phe 44346726

Soil Photolysis 22 (0.25 d) 13 (18 d) sandy loam, phe 44346728

Unextracted 

Residues

Soil Photolysis 47.3 (18 d) 47.3 (18 d) sandy loam, phe 44346728

Aerobic Soil

75 (14 d) 60.9 (365 d) Howe soil U.S., phe 44346729

58 (30 d) 50 (100 d) BBA 2.1 soil, phe 44346729

69 (100 d) 62 (100 d) BBA 2.2 soil, phe 44346729

81 (1 d) 77 (100 d) Laacher Hof soil, 

carb 44346729

60 (8 d) 50 (100 d) Howe soil U.S., carb 44346730

40 (100 d) 40 (100 d) Laacher Hof Soil, 

carb 44346730

Aerobic Aquatic

74.61 (100 d) 74.6 (100 d) Lake Honniger, phe 44518701

76.7 (60 d) 70.0 (100 d) Lake Stanley, phe 44518701

Anaerobic Soil 73.1 (360 d) 73.1 (360 d) Howe soil U.S., phe 44346731

na=not analyzed; nd=not detected; AR=applied radioactivity; d=days; h=hours; phe=phenyl ring radiolabeled; 

carb=carbmoxide ring radiolabeled

1 This Table was created from information in the data evaluation records (Cowles and Steeger, 1999, D244921) and 

the MRIDs. Many values reflect averaged data. 

2 Maximum amounts of organic volatiles were minimal.

3 Many of the metabolism studies had multiple unidentified minor degradates that were not identified. They were 

not added together and placed under the unidentified compound(s) list as their presence was expected to have little 

impact on decision making.

4 M1 and M2 structures were characterized together as the exact structures and radioactivity associated with each 

structure were uncertain. The maximum amount of a single compound (excluding succinic acid was reportedly 7%). 

+Denotes that the value reflects radioactivity associated with multiple compounds, when considered alone made up 

less than 10% of applied radioactivity.

Mobility/Sorption Summary

Fenhexamid is classified as moderately mobile to slightly mobile with organic carbon 

normalized Freundlich soil-water distribution coefficients (Kfoc) ranging from 446 to 1226 L/kgorganic carbon measured in six soils (MRID 44342722)27

. Linear sorption coefficients were not 

 

27 Classification is based on the FAO classification system (USEPA, 2010a)
Page 55 of 71

previously determined. Freundlich exponents ranged from 0.76 to 0.86 indicating that the 

equilibrium concentration in water influences sorption. The mean Kfoc was 878 L/kg-organic 

carbon and the coefficient of variation for Kfoc values (32%) is less than that for Kf values (39%) 

indicating that Kfoc values will be better at predicting sorption across soils than Kf values. 

Additionally, Kfs tend to be higher as the percent organic carbon increases. Consistent with 

water solubility increasing with pH, Kfoc values decrease with increasing pH. Based on the range 

of sorption coefficients, fenhexamid has the potential to reach ground water, especially in 

vulnerable sandy soils with low organic-carbon content and/or the presence of shallow ground 

water. Leaching may be mitigated by rapid formation of unextracted residues in soils. The 

maximum depth at which it was detected in terrestrial field dissipation studies was 15 cm. The 

mobility of the degradate WAK 7004 has higher Kfoc values (2324 to 5037 L/kg in four soils) 

than fenhexamid. 

Table A3. Freundlich Sorption Coefficients for Fenhexamid Measured at 19oC

Soil Kf Kfoc 1/n pH %OC

Laacher Haf

Germany

loamy sand

8.02 446 0.83 7 1.8

Borstel

German

loamy sand

10.21 888 0.86 6.3 1.2

Stanley

Kansas

silty clay

10.75 1024 0.81 5.6 1.1

Howe

Indiana

sandy loam

7.69 1025 0.76 7.1 0.75

Vero Beach

Florida

sand

2.45 1226 0.85 5.1 0.2

Napa

California

clay loam

6.52 658 0.86 7.7 1.0

Table A4. Freundlich Sorption Coefficients for WAK7004

Soil KF Kfoc 1/n pH %OC

Stanley

Kansas

silty clay

24.4 2324 0.86 5.6 1.1

Howe

Indiana

sandy loam

26.4 2421 0.86 7.1 0.75

Vero Beach

Florida

sand

10.1 5037 0.89 5.1 0.2

Napa

California

clay loam

32.1 3212 0.9 7.7 1.0
Page 56 of 71

Bioconcentration Summary

Bluegill sunfish (MRIDs 44346746) were exposed to 14C-fenhexamid (phenyl label) for 28 days 

under flow through conditions at high and low concentrations (20 and 200 μg/L, pH 7.0 to 7.5;

supplemental; 20-23oC). The bioconcentration factor for total radioactivity was 132-185 L/kgwet weight whole fish and 36.7 to 60.1 L/kg-wet weight in edible tissue, and 248 to 339 in 

viscera.Total 14C residues in fish were measured via combustion. Tissue residues were further 

characterized via solvent extraction and HPLC and LC-MS. Transformation products observed 

include 4-hydroxy-KBR 2738, 3-hydroxy-KBR 2738 and KBR-glucuronide. Conjugation 

occurred at the aromatic hydroxyl group and with hydroxylation of the cyclohexyl ring. The 

depuration half-life was less than 1 day. As previously identified, there is still uncertainty in the 

BCF as concentrations of fenhexamid and degradates were not fully characterized.
Page 57 of 71

Appendix B. Screening Level Usage Analysis

Fenhexamid (090209)

Screening Level Usage Analysis (SLUA)

Date: June 19, 2012

What is a Screening Level Usage Analysis (SLUA)?

Available estimates of pesticide usage data for a particular active ingredient that is 

used on agricultural crops in the United States.

Pesticide usage data obtained from various sources. The data are then merged, 

averaged, and rounded so that the presented information is not proprietary, business 

confidential, or trade secret. 

What does it contain?

Pesticide usage data for a single active ingredient only.

Agricultural use sites (crops) that the pesticide is reported to be used on.

Available pesticide usage information from U.S. states that produce 80% or more of a 

crop, in most cases, or less than 80%, in rare cases, depending on the scope of the 

survey and available resources.

Annual percent of crop treated (average & maximum) for each agricultural crop.

Average annual pounds of the pesticide applied for each agricultural crop (i.e., for the 

states surveyed, not for the entire United States).

What assumptions can I make about the reported data?

Average pounds of active ingredient applied - Values are calculated by merging 

pesticide usage data sources together; averaging across all observations, then 

rounding. Note: If the estimated value is less than 500, then that value is labeled 

<500. Estimated values between 500 & <1,000,000 are rounded to 1 significant 

digit. Estimated values of 1,000,000 or greater are rounded to 2 significant digits.)

Average percent of crop treated - Values are calculated by merging data sources 

together; averaging by year, averaging across all years, & rounding to the nearest 

multiple of 5. Note: If the estimated value is less than 2.5, then the value is labeled 

<2.5. If the estimated value is less than 1, then the value is labeled <1.

Maximum percent of crop treated - Value is the single maximum value reported 

across all data sources, across all years, & rounded up to the nearest multiple of 5. 

Note: If the estimated value is less than 2.5, then the value is labeled <2.5.

What are the data sources used?

USDA-NASS (United States Department of Agriculture’s National Agricultural 

Statistics Service) – pesticide usage data from 2003 to 2010.

Private pesticide market research – pesticide usage data from 2003 to 2010.

California Department of Pesticide Regulation (DPR) Pesticide Use Reporting

(PUR) data for 2003 to 2010.

What are the limitations to the data?

Additional registered uses may exist but are not included because the available 

surveys do not report usage (e.g., small acreage crops).

Lack of reported usage data for the pesticide on a crop does not imply zero usage.
Page 58 of 71

Usage data on a particular site may be noted in data sources, but not quantified. In 

these instances, the site would not be reported in the SLUA.

Non-agricultural use sites (e.g., turf, post-harvest, mosquito control, etc.) are not 

reported in the SLUA. A separate request must be made to receive these estimates.

Some sites show some use, even though they are not on the label. This usage could 

be due to various factors, including, but not limited to Section 18 requests, existing 

stocks of the chemical, data collection errors, and experimental use permits (EUPs). 

 

June 19, 2012

Screening Level Estimates of Agricultural Uses of Fenhexamid (090209)

Sorted Alphabetically

Reporting Years: 2003-2010

Percent Crop Ttd.

Crop Lbs. A.I. Avg. Max.

1 Apricots <500 10 10

2 Blueberries 2,000 5 15

3 Caneberries 4,000 20 40

4 Cherries 1,000 <2.5 10

5 Grapes 30,000 5 15

6 Peaches <500 <1 <2.5

7 Pistachios* 2,000 NC NC

8 Plums/Prunes <500 <1 <2.5

9 Strawberries 40,000 50 65

All numbers are rounded.

<500: indicates less than 500 pounds of active ingredient.

 <2.5: indicates less than 2.5 percent of crop is treated.

 <1: indicates less than 1 percent of crop is treated.

* California data only.

NC: not calculated, only pounds a.i. is available. 

SLUA data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural Statistics Service) 

Private Pesticide Market Research

California DPR (Department of Pesticide Regulation)

These results reflect amalgamated data developed by the Agency and are releasable to the public.
Page 59 of 71

Appendix C. SIP/STIR Model Results

(a) SIP Version 1.0 Model Output
Page 60 of 71

(b) STIR Version 1.0 Model Output
Page 61 of 71

Appendix D. Reference List for OPPTS 835 Guidelines and 850 Guidelines Related to Fate

The Office of Prevention, Pesticides, and Toxic Substances (OPPTS) became the Office of 

Chemical Safety and Pollution Prevention (OCSPP) in 2011. The guidelines have not been 

updated since the name change and the titles still use OPPTS.

OPPTS or OCSPP

Guideline

Citation

Hydrolysis

835.2120

(161-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2120 Hydrolysis. E. 

712-C-08-012. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aqueous Photolysis 

835.2240

(161-2)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2240 

Photodegradation in Water. E. 712-C-08-013. October 2008. Office of Prevention, Pesticides, and 

Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Soil Photolysis

835.2410

(161-3)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2410 

Photodegradation in Soil. E. 712-C-08-015. October 2008. Office of Prevention, Pesticides, and 

Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aerobic Soil 

Metabolism 

835.4100

(162-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.4100 Aerobic Soil 

Metabolism; OPPTS 835.4200 Anaerobic Soil Metabolism. EPA712-C-08-016 & E. 712-C-08-017. 

October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States Environmental 

Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 17, 

2012).

Anaerobic Soil 

Metabolism

835.4200

(162-2)

Aerobic Aquatic 

Metabolism 

835.4300

(162-4)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.4300 Aerobic Aquatic 

Metabolism; OPPTS 835.4400 Anaerobic Aquatic Metabolism. EPA 712-C-08-018 & E. 712-C-08-

019. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 17, 

2012).

Anaerobic Aquatic 

Metabolism 

835.4400

(162-3)

Sorption coefficients

835.1230

(163-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1230 

Adsorption/Desorption (Batch Equilibrium). E. 712-C-08-009. October 2008. Office or Prevention, 

Pesticides, and Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Leaching and Aged 

Column Leaching 

835.1240

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1240 Leaching Studies. 

E. 712-C-08-010. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United 

States Environmental Protection Agency. Available at 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0007 (Accessed May 

5, 2012).
Page 62 of 71

OPPTS or OCSPP

Guideline

Citation

Terrestrial Field 

Dissipation

835.6100

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1230 

Adsorption/Desorption (Batch Equilibrium). E. 712-C-08-009. October 2008. Office or Prevention, 

Pesticides, and Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aquatic Field 

Dissipation

835.6200

USEPA. 2008. Fate, Transport, and Transformation Test Guidelines. OPPTS Aquatic (Sediment) 

Field Dissipation. EPA 712-C-08-021. October 2008. Office of Prevention, Pesticides, and Toxic 

Substances. United States Environmental Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 15, 

2012).

Bioconcentration 

Factor

850.1730

USEPA. 1996. Ecological Effects Test Guidelines. OPPTS 850.1730 Fish BCF. E. 712-C-96-129. 

April 1996. Environmental Fate and Effects Division. Office of Pesticide Programs. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_T

est_Guidelines/Drafts/850-1730.pdf (Accessed May 14, 2012).

Environmental 

Chemistry Method

850.6100

USEPA. 2012. Ecological Effects Test Guidelines. OCSPP 850.6100: Environmental Chemistry 

Methods. EPA 712-C-001. January 2012. Office of Chemical Safety and Pollution Prevention. 

United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series850.htm (Accessed August 

10, 2012).
Page 63 of 71

Appendix E. AOPWIN V1.92 Output

SMILES : c1cc(c(CL)c(c1NC(=O)C2(CCCCC2)C)CL)O

CHEM : 

MOL FOR: C14 H17 CL2 N1 O2 

MOL WT : 302.20

------------------- SUMMARY (AOP v1.92): HYDROXYL RADICALS (25 deg C) --------

Hydrogen Abstraction = 13.7303 E-12 cm3/molecule-sec

Reaction with N, S and -OH = 0.1400 E-12 cm3/molecule-sec

Addition to Triple Bonds = 0.0000 E-12 cm3/molecule-sec

Addition to Olefinic Bonds = 0.0000 E-12 cm3/molecule-sec

**Addition to Aromatic Rings = 3.5808 E-12 cm3/molecule-sec

Addition to Fused Rings = 0.0000 E-12 cm3/molecule-sec

 OVERALL OH Rate Constant = 17.4511 E-12 cm3/molecule-sec

 HALF-LIFE = 0.613 Days (12-hr day; 1.5E6 OH/cm3)

 HALF-LIFE = 7.355 Hrs

........................ ** Designates Estimation(s) Using ASSUMED Value(s)

------------------- SUMMARY (AOP v1.91): OZONE REACTION (25 deg C) -----------

 ****** NO OZONE REACTION ESTIMATION ******

 (ONLY Olefins and Acetylenes are Estimated)

NOTE: Reaction with Nitrate Radicals May Be Important!

Experimental Database: NO Structure Matches
Page 64 of 71

Appendix F. Currently Registered Products Containing Fenhexamid

Table F1. Currently Registered Products Containing Fenhexamid

Registration 

Number Product Name Registration Status Company Name

Percent 

Active 

Ingredient

Active 

Ingredient

264-780 FENHEXAMID 

50 WDG

Conditionally 

Registered (16-Apr2002)

BAYER 

CROPSCIENCE 

LP

50 Fenhexamid

264-785 FENHEXAMID 

TECHNICAL

Conditionally 

Registered (07-Jun2002)

BAYER 

CROPSCIENCE 

LP

98.6 Fenhexamid

66330-35

ELEVATE 50 

WDG 

FUNGICIDE

Conditionally 

Registered (21-May1999)

ARYSTA 

LIFESCIENCE 

NORTH 

AMERICA, 

LLC

50 Fenhexamid

66330-36 FENHEXAMID 

TECHNICAL

Conditionally 

Registered (21-May1999)

ARYSTA 

LIFESCIENCE 

NORTH 

AMERICA, 

LLC

98.6 Fenhexamid

66330-48

CAPTEVATE 68 

WDG 

FUNGICIDE

Conditionally 

Registered (09-Jul2003)

ARYSTA 

LIFESCIENCE 

NORTH 

AMERICA, 

LLC

14.3 Fenhexamid

53.6 Captan
Page 65 of 71

Appendix G. Summary of exposure pathways, endpoints, and models that will be used in 

the risk assessment.

Table G1. Summary of exposure pathways, endpoints, and models used in the registration 

review risk assessment for fenhexamid.

Assessed 

Group

Endpoints 

Evaluated

Transport and Exposure 

Pathway

Method of Estimating 

Exposure

Aquatic 

Vertebrates

Acute: 96-hr LC50

Chronic: NOAEC

Spray drift and runoff to water 

column and sediment

PRZM/EXAMS, AgDRIFT or 

AgDISP

Method to be determined

Aquatic 

Invertebrates

Acute: 48-hr LC50/EC50

Chronic: NOAEC

Aquatic Plants EC50

Terrestrial 

Vertebrates

Acute: Oral LD50/

DietaryLC50

Chronic: NOAEC

Spray Drift and direct spray to

Residues on foliage

Residues in drinking water

Inhalation 

Bioconcentration/Bioaccumulation

AgDRIFT or AgDISP

TREX, AgDRIFT or AgDISP

Method to be determined

Method to be determined

KABAM

Terrestrial 

Invertebrates Method under development

Terrestrial 

Plants

EC25, EC05, and 

NOAEC

Runoff (vegetative vigor and 

seedling emergence) and Spray 

Drift (vegetative vigor)

Water used as irrigation water

TERRPLANT and AgDRIFT or 

AgDISP

PRZM-GW, SCIGROW, and 

PRZM/EXAMs

Human Health 

Drinking Water See Human Health 

Toxicity Assessment

Surface Water

Ground Water

PRZM/EXAMs

SCIGROW and PRZM-GW
Page 66 of 71

Appendix H. Preliminary Rough Estimate of Exposure Assuming Unextracted Residues 

are a Residue of Concern. 

This analysis does not account for potential exposure with anilides as residues of concern. It 

only considers parent and unextracted residues as residues of concern. Additionally, only one 

scenario was modeled. These are preliminary estimates of exposure only.

1 in 10 Year Estimated Environmental Concentrations of Fenhexamid and unextracted residues 

using PRZM/EXAMs

Residues

Fenhexamid Residue concentration in Surface Water (μg/L)

Ecological Sediment Pore Water Human Health Drinking Water

peak 21-

day

60-

day peak 21-day

60-

day Peak Annual Average

Fenhexamid + 

Unextracted 

Residues

69 45 23 15 14 12 165.2 6.9

Fenhexamid Alone 14 8.8 3.8 2.1 2.1 1.9 24 0.37

Table H1. PRZM/EXAMs Input Parameter Values for Fenhexamid (Parent and 

Unextracted Residues)

1

Parameter Value Source Comment

PRZM Scenario FLcucumberSTD.txt --

EXAMs environment pond298.exv (Eco)

ir298.exv (DW) --

Field Size EPA Pond (Eco)

Reservoir (DW) --

Runoff flow None --

Molecular Weight 

(g/mole) 302.2 --

Henry’s Law Constant 

(atm-m

3

/mole) 6×10-11 Calculated

Vapor Pressure (Torr) 7×10-9 MRID 44346720

Solubility 20 MRID 44346719 pH 5-7

Soil-water distribution 

Coefficient (Kd; L/kg 

soil)

no input --

Organic-carbon 

normalized soil-water 

distribution coefficient

(KOC; L/kg OC)

878 MRID 44346722 Mean of six KFOC values. KOC values 

were not calculated.

CAM 2 --

Incorporation Depth 0 --

Application Efficiency 0.95 --

Spray Drift Fraction 0.05 (Eco)

0.16 (DW) --

Application Date 16-10 -- Date of emergence in scenario
Page 67 of 71

Parameter Value Source Comment

Application Rate kg 

a.i./hectare (lbs a.i./A)1 0.84 (0.75)

EFED Table 1 

LUIS Report

Application rates on ornamentals are 

uncertain and could be higher

Number of Applications 4

Assumed from the maximum single 

application rate and maximum annual 

application rate of 3 lbs a.i./A.

Interval between 

Applications (days) 3

The interval between application is not 

specified for all uses

IPSCND 3 (Left As is on foliage) -- --

Hydrolysis (days) 0 MRID 44346725 --

Aquatic Photolysis 

Half-life at pH 7 (days)

0.1 MRID 44346732 --

Water Half-life (days) Parent: 19

Parent+Unextracted: 1025 MRID 44518701

The 90th percentile upper confidence 

bound on the mean of four half-life 

values. 

Benthic half-life (days) Parent: 345

Parent+Unextracted: 3078 MRID 44346731 Anaerobic Soil Half-life x 3

Aerobic Soil 

Metabolism Half-life 

(days)

Parent: 2.6

Parent+Unextracted

Residues: 700

MRID 45643802

The 90th percentile upper confidence 

bound on the mean of four half-life 

values. When a study on one soil was 

conducted with different rings labeled 

the values were averaged so that there 

was one value for each soil tested.

Eco=input value for ecological risk assessment; DW=input value for human health drinking water assessment

All input parameters were chosen consistent with Standard Operating Procedure for Using the NAFTA Guidance to 

Calculate Representative Half-life Values and Characterizing Pesticide Degradation. (Bohaty et al., 2012; NAFTA, 

2012) and Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of 

Pesticides, Version 2.1 (USEPA, 2009b).
Page 68 of 71

Appendix I. Toxicity Profile for Fenhexamid.

Table 1. Aquatic toxicity studies for fenhexamid.

Group

Species

(Common 

Name)

Study Type

(Measured 

Effect)

Test 

Substance 

(% a.i.)

Endpoint

(Test 

Duration)

Toxicity Value

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Freshwater Fish1

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

Technical

92.7%

LC50

(96 hours)

1.34

(moderately 

toxic)

44346742

(Acceptable)

WG-50

(49%)

LC50

(96 hours)

1.23*

(moderately 

toxic)

44523605

(Acceptable)

Chronic: Early 

Life-Stage

(Time to swim 

up)

Technical

(95.9%)

NOAEC

LOAEC

0.101*

0.206

44346745

(Acceptable)

Lepomis 

macrochirus

(Bluegill 

sunfish)

Acute

(Survival)

Technical

(94.64%)

LC50

(96 hours)

3.42

(moderately 

toxic)

44346741

(Acceptable)

Estuarine/

Marine Fish

Cyprinodon 

variegatus

(Sheepshead 

minnow)

Acute

(Survival)

Technical

(≥95%)

LC50

(96 hours)

11*

(slightly toxic)

44346743

(Acceptable)

Freshwater 

Invertebrates

Daphnia 

magna

Acute 

(Immobilization)

Technical

(95.7%)

EC50

(48 hours)

>18.8†

(Slightly toxic 

to practicallynon-toxic)

44366507

(Supplemental)

WG-50

(49.6%)

EC50

(48 hours)

105

(Practically 

non-toxic)

44523604 

(Supplemental)

Chronic lifecycle (growth 

[length]; larval 

survival)

Technical

(95.9%)

NOAEC

LOAEC

1.0*

1.9

44346744

(Acceptable)

Estuarine/

Marine 

Invertebrates

Americamysis

bahia

(Mysid shrimp)

Acute

(Survival)

Technical

(95.8%)

LC50

(96 hours)

4.6*

(moderately 

toxic)

44346740

(Acceptable)

Vascular Aquatic 

Plants

Lemna gibba

(duckweed)

(Frond number, 

growth rate, 

biomass)

Technical

(97.7%)

EC50

(14 days) >2.3†

44731105

NOAEC (Acceptable)

(14 days) 0.28*

Non-Vascular 

Aquatic Plants

Pseudokirchneri

ella subcapitata

(green algae)

(Cell density)

Technical

(95.7%)

EC50

(120 hours) 4.82 44518706

NOAEC (Supplemental)

(120 hours) 2.95

WG-50

(49.6%)

EC50

(72 hours) 1.37*

44523610

NOAEC (Supplemental)

(72 hours) 0.558*

EC50 Effect concentration for 50% of the organisms tested; NOAEC no observed adverse effect concentration
Page 69 of 71

* Most sensitive endpoint and will be used for RQ calculations unless more sensitive data become available.

† Non-definitive study endpoint; cannot be used to calculate RQs for risk estimation.

‡ Freshwater fish may be surrogates for aquatic-phase amphibians.

Table 2. Terrestrial toxicity studies for fenhexamid.

Group Species Study Type 

(Effect)

Test 

Substance

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Birds‡

Anas 

platyrhynchos 

(mallard duck)

Sub-acute dietary 

(Survival)

Technical

(95.7%)

LC50

(5 days)

>4,962 mg a.i./kgdiet†

(Practically nontoxic)

44346752

(Supplemental)

Colinus 

virginianus

(Northern 

Bobwhite Quail)

Acute oral 

(Survival)

Technical

(95.7%)

LD50

(14 days)

>2,000 mg a.i./kgbw†

(Practically nontoxic)

44346750

(Supplemental)

Sub-acute dietary 

(Survival)

Technical

(95.7%)

LC50

(5 days)

>5,469 mg a.i./kgdiet†

(Practically nontoxic)

44346751

(Supplemental)

Reproductive 

toxicity

(Feed consumption 

rate)

Technical

(95.9%)

NOAEC/ 

LOAEC

(23 weeks)

2,074/>2,074

mg a.i./kg-diet*

44346753

(Acceptable)

Mammals

Rattus 

norvegicus

(Norway rat)

Acute oral 

(Survival)

Technical

(95.5%)

LD50

(Survival)

>5,000 mg a.i./kgbw

(Practically nontoxic)

44346769

Rat 2-generation 

reproductive 

toxicity test

(decreased body 

weights)

Technical

(93.8-

95.2%)

NOAEC/

LOAEC

500/5,000 mg 

a.i./kg-diet 44346803

Terrestrial 

Invertebrates

Apis mellifera 

(honeybee)

Acute Contact 

Toxicity 

(Survival) 

Technical

(95.7%)

LD50

(48 hours) >200 μg a.i./bee

44346755

(Acceptable)

Acute Oral 

Toxicity 

(Survival) 

Technical

(94%)

LD50

(48 hours) >201 μg a.i./bee 44346755(Supplemental)

Terrestrial 

Plants No Toxicity Data Available
Page 70 of 71

Appendix J. Data Call-In Justification Tables for Non-guideline Studies

Study Title: Honeybee Larval Toxicity Study

Guideline Number: Non-guideline

Test Substance: Fenhexamid—TGAI

Rationale for Requiring the Data

Although fenhexamid is practically non-toxic to adult worker bees on an acute contact exposure 

basis, a larval toxicity study is needed to determine the toxicity of the compound to developing 

brood. This study is part of EFED’s current screening level process for determining potential 

effects to terrestrial invertebrates. Therefore, a non-guideline honeybee larval toxicity study is 

recommended. The registrant should submit a proposed protocol for review and approval by 

EFED prior to initiation of the study.

Practical Utility of the Data

How will the data be used?

Data will be used to assess risk to non-target listed and non-listed terrestrial invertebrate species. 

This study would allow the Agency to refine the screening-level hazard assessment for beneficial 

terrestrial invertebrates. The effects data will be used to determine the potential for adverse effects 

on beneficial terrestrial invertebrates through direct effects on larval bees. 

How could the data impact the Agency’s future decision-making?

EPA is required by section 7(a)(2) of the Endangered Species Act (ESA) to ensure that any action 

it authorizes or takes “...is not likely to jeopardize the continued existence of any endangered or 

threatened species or result in the destruction or adverse modification of critical habitat” and “to 

use the best scientific data available” in carrying out this obligation. The data EPA intends to call 

in are necessary to inform the determination required by ESA as to whether continued registration 

of a pesticide is or is not likely to jeopardize the species or its designated critical habitat. The lack 

of these data will limit the flexibility that the Agency has in coming into compliance with ESA 

and could result in use restrictions that are unnecessarily severe. In addition, the lack of these data 

may result in an uncertain assumed risk and potential mitigation of fenhexamid formulations under 

FIFRA.

Study Title: Whole sediment chronic freshwater and/or marine invertebrate (3 Studies)

Guideline Number: Agency-wide Guideline

Test Substance: Fenhexamid—TGAI

Rationale for Requiring the Data

The use pattern, chemical properties, estimated exposure, and toxicity profile of fenhexamid

indicate need for chronic (life cycle) sediment toxicity tests to fully evaluate potential risks to 

benthic invertebrates. These sediment toxicity studies include two freshwater species (the midge, 

Chironomus dilutus and the amphipod, Hyalella azteca) and one saltwater species (the amphipod, 

Leptocheirus plumulosus). Multiple species are being recommended in order to account for 

differential sensitivity and exposure potential of benthic invertebrates to fenhexamid. This 

recommendation is being made because some KOC and log Kow values in submitted fate studies 

were above the thresholds of 1,000 and 3.0, respectively. The registrant should submit a proposed 

protocol for review and approval by EFED prior to initiation of the study.

(Note: As an alternative to the conduct of three chronic (life cycle) sediment toxicity tests, EFED 
Page 71 of 71

would also consider a tiered testing approach for sediment toxicity testing. In this approach, 

sediment toxicity testing would first be conducted with the aforementioned species using the 10-d 

(subchronic) sediment toxicity test guidelines (OSCPP 850.173528 and 850.174029). Then, 

pending a comparison of estimated environmental concentrations (EEC) in sediment and pore 

water with toxicity results from the 10-d sediment toxicity studies, the need for one or more 

chronic sediment toxicity studies would be determined. This tiered testing approach has the 

potential advantage of reducing the number of chronic (life cycle) studies that would be needed 

when results of the 10-d (subchronic) tests in conjunction with sediment EECs indicate chronic 

testing is not likely to alter risk assessment conclusions. In some cases, however, this tiered 

testing approach may result in the conduct of both a 10-d (subchronic) and a chronic (life cycle) 

study. If the tiered test approach described above is not preferred, then chronic life-cycle sediment 

toxicity studies be carried out on the three preferred species, C. dilutus, H. azteca, and L. 

plumulosus.)

Practical Utility of the Data

How will the data be used?

Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms 

associated with uses of fenhexamid. The data will reduce uncertainties associated with the current 

risk assessment for benthic species and will improve our understanding of the potential effects of 

fenhexamid on aquatic ecosystems.

How could the data impact the Agency’s future decision-making?

If the data indicates that registered fenhexamid uses may pose a risk of adverse effects to nontarget benthic organisms above the Agency Level of Concern, the Agency may explore decision 

options to mitigate this risk. The lack of these data will limit the flexibility the Agency and 

registrants have in coming into compliance with the Endangered Species Act, and could result in 

use restrictions for fenhexamid which may otherwise be avoided, or which are unnecessarily 

severe.

 

28 USEPA. 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/

Drafts/850-1735.pdf

29 USEPA. 1996. 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_Test_Guidelines/

Drafts/850-1740.pdf