Environmental Fate and Ecological Risk Assessment for the 

Registration Review of Fenoxaprop-p-ethyl

Fenoxaprop-p-ethyl

CAS 71283-80-2 PC Code 129092

21 April 2014

Prepared by

Scott Glaberman, Ph.D., Biologist

Chuck Peck, Environmental Engineer

U.S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division (EFED)

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by

Thomas Steeger, Ph.D., Senior Science Advisor

Jim Carleton, Ph.D., Senior Scientist

Sarah Winfield, Acting Branch Chief

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Table of Contents

1. Executive Summary ...........................................................................................................................................3

2. Problem Formulation .......................................................................................................................................7

2.1. Nature of Regulatory Action....................................................................................................................7

2.2. Stressor Source and Distribution ............................................................................................................7

2.2.1. Nature of the Chemical Stressor ...........................................................................................................7

2.2.2. Overview of Pesticide Usage .............................................................................................................9

2.3. Receptors ..................................................................................................................................................9

2.3.1. Aquatic and Terrestrial Effects........................................................................................................9

2.3.2. Ecosystems Potentially at Risk .........................................................................................................9

2.4. Assessment Endpoints............................................................................................................................10

2.5. Conceptual Model ...................................................................................................................................10

2.5.1. Risk Hypotheses ................................................................................................................................11

2.5.2. Conceptual Diagram .........................................................................................................................11

2.6. Analysis Plan ...........................................................................................................................................13

2.6.1. Measures of Exposure ....................................................................................................................13

2.6.2. Measures of Effect..........................................................................................................................15

2.6.3. Integration of Exposure and Effects.............................................................................................15

3. Analysis............................................................................................................................................................17

3.1 Use Characterization...................................................................................................................................17

3.2. Exposure Characterization....................................................................................................................18

3.2.1. Environmental Fate and Transport Characterization .................................................................18

3.2.2. Measures of Aquatic Exposure.......................................................................................................22

3.2.3. Measures of Terrestrial Exposure..................................................................................................28

3.3. Ecological Effects Characterization......................................................................................................32

3.3.1. Aquatic Toxicity Assessment..........................................................................................................33

3.3.2. Terrestrial Effects Characterization..............................................................................................41

3.3.3. Review of Incident Data..................................................................................................................47

4. Risk Characterization......................................................................................................................................48

4.1. Risk Estimation.......................................................................................................................................48

4.1.1. Aquatic Organisms.................................................................................................................................48

4.1.2. Terrestrial Organisms.....................................................................................................................60

4.2. Risk Description......................................................................................................................................65

4.2.1. Risks to Aquatic Organisms ...........................................................................................................65

4.2.2. Terrestrial Organisms.....................................................................................................................67

4.3. Conclusions .............................................................................................................................................71

5. Listed Species of Concern................................................................................................................................72

5.1. Action Area .............................................................................................................................................73

5.2. Taxonomic Groups Potentially at Risk.................................................................................................73

5.3. Listed Species Occurrence Associated with FPE Uses ........................................................................75

6. Endocrine Disruptor Screening Program ......................................................................................................77

7. References.........................................................................................................................................................77

7.1. Submitted Product Chemistry and Environmental Fate Studies.......................................................80

7.2. Submitted Ecotoxicity Studies...............................................................................................................81

Appendix A. Chemical Names and Structures of FPE and its Degradates .........................................................89

Appendix B. PRZM/EXAMS Sample Input/Output Data ....................................................................................90

Appendix C. Example T-REX Input and Output for FPE (based on upper bound Kenaga EECs for use on 

ornamentals) ............................................................................................................................................................107

Appendix D. Example TERRPLANT (v. 1.2.2) Input and Output for FPE......................................................109

Appendix E. STIR Results for FPE.......................................................................................................................110

Appendix F. SIP Results for FPE..........................................................................................................................111

Appendix G. PFAM Modeling for Rice Applications of FPE .............................................................................112

Appendix H. ECOSAR Quantitative Structure-Activity Relationship (QSAR) Toxicity Predictions for FPE 

and Transformation Products. ...............................................................................................................................116
-Page 3 of 116-

1. Executive Summary

The preliminary risk assessment (PRA) examines the potential ecological risks associated with 

labeled uses of the herbicide fenoxaprop-p-ethyl (FPE), based on the best available scientific and 

commercial information on the use, environmental fate and transport, and effects of FPE on nontarget organisms.

This assessment was conducted for FPE, which is the R-enantiomer (or d-isomer) of the racemate 

fenoxaprop-ethyl (PC Code 128701). In the early 1990s, the registrant for fenoxprop-ethyl 

amended the registration, enriching the formulations to contain more FPE, as it was considered the 

herbicidally-active isomer. As of 2002, all end-use products were registered for FPE and the 

racemate is no longer registered by EPA. Most registrant-submitted toxicity studies used in this 

assessment were performed with FPE (i.e., d-isomer enriched); however, in several cases where 

data gaps exist for FPE, toxicity data were bridged from fenoxaprop-ethyl (i.e., mixture of R- and 

S-enantiomers) for use in risk assessment. This bridging strategy is considered appropriate, since 

fenoxaprop-ethyl also contains the R-enantiomer.

From the submitted fate studies, the degradation pattern of fenoxaprop-p-ethyl was well 

established: de-esterification of fenoxaprop-p-ethyl to the fenoxaprop-p acid, with subsequent 

degradation to 4-(6-chloro-2-benzoxazolyloxy)phenol, chlorobenzoxazolone, and eventually to 

CO2. This de-esterification process was dependent on both abiotic and microbially-mediated 

hydrolysis. In evaluating potential risks to terrestrial species, exposure and risk estimates were 

developed for the combined residues of FPE and its three degradates fenoxaprop-p acid, 4-(6-

chloro-2-benzoxazolyloxy)phenol, and chlorobenzoxazolone, since sufficient toxicity information 

on the transformation products was not available to eliminate them from potential concern. This 

was accomplished by including both parent and degradates in the dissipation half-life used to 

estimate residues on terrestrial food items. Conversely, available aquatic effects data indicate that 

FPE transformation products are less toxic to aquatic plants and animals than the parent.

Therefore, aquatic exposure modeling was conducted for the parent, FPE, alone. 

For aquatic organisms, the screening-level assessment with preliminary refinements concludes that 

the use of FPE in accordance with current and proposed labels results in potential acute risks of 

concern for federally threatened and endangered (listed) freshwater vertebrates (fish and aquaticphase amphibians) inhabiting rice paddies when paddy water is drained down to 1 inch; the 

likelihood of such a scenario is considered low. Additional screening-level risks of concern to 

aquatic organisms for the labeled use on rice were alleviated by refinements in the modeling of 

residue concentrations in rice paddy water and in water released from paddies. Although several 

chronic toxicity studies with freshwater invertebrates indicate that formulations containing FPE 

may be two orders of magnitude more toxic than FPE technical grade active ingredient (TGAI),

the components of a formulation are assumed to have different fate and transport properties from 

the active ingredient (e.g., mobility, affinity to soil versus water, degradation kinetics). 

Consequently, aquatic organisms are not expected to be chronically exposed to the formulation, 

and therefore, the scenario is not assessed in this analysis.

For terrestrial organisms, no acute or chronic risks of concern are identified for birds, as well as

terrestrial phase amphibians or reptiles, for which birds serve as surrogates. For mammals, the 
-Page 4 of 116-

chronic risk level of concern (LOC) is not exceeded for the grass grown from seed use for any size 

class or dietary item based on estimated dietary or dose-based concentrations. For the barley, 

conservation reserve, cotton, rice, and soybean uses, the chronic risk LOC is exceeded for dosebased estimates of small and/or medium sized mammals feeding on short grass. For the 

ornamentals and rights-of-way uses, the chronic risk LOC is exceeded for dose-based estimates of 

multiple size classes and dietary items. This assessment also indicates that all labeled uses of FPE 

pose potential risks of concern to listed and non-listed monocotyledonous (monocot) terrestrial 

plants, which is supported by a series of incidents reported for grain crops treated with FPE. These 

results also indicate that large spray drift buffer distances (85 to >1,000 feet) may be needed to 

protect non-target monocot plants from effects from spray drift.
-Page 5 of 116-

Table 1.1. Risk Assessment Summary for Non-Target Aquatic Organisms

Aquatic Invertebrates Aquatic Vertebrates Aquatic Plants

Sediment 

Organisms

Acute Chronic Acute Chronic

Freshwater Estuarine/

Marine Freshwater Estuarine/Marine Freshwater Estuarine/Marine Freshwater Estuarine/Marine Vascular Nonvascular

RQs Not calculated5 <0.01-0.03 0.01-0.76 <0.01 <0.01-0.08 <0.01-0.18 Not 

calculated1 ≤0.01 Not calculated1

Listed 

Species:

<0.01-0.03

Listed 

Species:

0.02-3.09

Non-Listed 

Species:

Not 

calculated1

Non-Listed 

Species:

<0.01-0.19

Non-listed 

Species

LOC

N/A 0.5 0.5 1.0 1.0 0.5 0.5 1.0 1.0 1.0 1.0

Listed 

Species LOC N/A 0.05 0.05 1.0 1.0 0.05 0.05 1.0 1.0 1.0 1.0

Risks of 

Concern 

(Uses)

Not 

expected

Not 

expected

Not 

expected 

(after 

refinements)

Not 

expected

Not 

expected

Not 

expected

(after 

refinements)4

Not 

expected

None 

expected

Not

expected

Not 

expected

Not expected

(after 

refinements)

Uncertainties

Typical sediment 

organism data not 

available; benthic 

exposure 

expected to be 

orders of 

magnitude below 

available aquatic 

toxicity endpoints

FE data 

used2; FPE 

EUP more 

toxic than 

TGAI.

EUP 5x to 

100x more 

toxic than 

TGAI on 

chronic 

basis

No chronic 

estuarine/

marine data 

available; ACR 

used for 

characterization

Refinements 

Used PFAM rice paddy concentrations used3

ACR = Acute-to-chronic ratio; FW = Freshwater; E/M = Estuarine/Marine; N/A = Not Applicable; EUP = end-use product

1 RQs not calculated since only a non-definitive endpoint exists. 

2 Fenoxaprop-ethyl toxicity data used because FPE toxicity endpoint was either unavailable or non-definitive.

3

If screening-level EECs exceed LOCs, the Pesticide Flooded Application Model (PFAM, version 1.05, September 2013) was used to refine rice use 

concentrations.

4 Non-listed species LOC is exceeded only when paddy water is drained to 1 inch.

5 No data on sediment dwelling invertebrates available for FPE or FE.
-Page 6 of 116-

Table 1.2. Risk Assessment Summary for Non-Target Terrestrial Organisms

Birds Mammals Terrestrial Plants Insect Pollinators Acute Chronic Acute Chronic Monocots Dicots

RQs <0.01-0.08 <0.01-0.24 ≤0.02 0.01-2.42

Listed Species:

Not calculated1

Non-Listed Species:

2.49-13.8

Listed Species:

Not calculated1

Non-Listed Species:

<0.01-0.37

Not calculated1

Non-listed 

Species

LOC

0.5 1.0 0.5 1.0 1.0 1.0 N/A

Listed 

Species LOC 0.1 1.0 0.1 1.0 1.0 1.0 0.4

Risks of 

Concern 

(Uses)

Not

expected

Not

expected

Not

expected

All uses except grass 

grown for seed

Except for uses on 

ornamentals and rightsof-way, LOC exceeded 

only for mammals 

feeding on short grass

LOCs exceeded for all labeled 

uses; supported by incidents.

Buffers distances of 85 to 1000+ 

feet may be needed to protect 

non-target monocots

2

Not 

expected

Practically non-toxic to young 

adult honey bees; risks of 

concern not expected based on 

TGAI data

Uncertainties

Passerine 

toxicity data 

not available

Definitive NOAEC not available 

from seedling emergence and 

vegetative vigor tests for 

monocots

Definitive NOAEC and EC25

not available from seedling 

emergence study

EUP more toxic than TGAI on 

acute contact basis

N/A = Not Applicable

1 RQs not calculated since only a non-definitive endpoint exists.

2 AgDRIFT used to estimate how far off-site spray drift exposure might occur at a level known to cause adverse effects in terrestrial plant toxicity studies.
-Page 7 of 116-

2. Problem Formulation

The purpose of problem formulation is to provide the foundation for the environmental fate and 

ecological risk assessment being conducted for the representative labeled uses of fenoxaprop-pethyl (FPE), which are summarized in the most recent Label Use Information System (LUIS) 

report compiled by the Biological and Economic Analysis Division (BEAD) (September 2012)

and the agreed upon label rate modifications provided by the registrants (Bayer CropScience, 2012 

and Syngenta Crop Protection, 2012). The problem formulation sets the objectives for the risk 

assessment and provides a plan for analyzing the data and characterizing the risk (USEPA 1998). 

As part of the Registration Review process, a detailed Problem Formulation (DP Barcode 

D338163) for this risk assessment was published to the docket [Docket ID: EPA-HQ-OPP-2007-

0437] in August 2007. The following section summarizes the key points of that document and 

discusses any differences between the analysis outlined there and the analysis conducted in this 

risk assessment. 

2.1. Nature of Regulatory Action

The risk assessment is conducted as part of the Agency’s Registration Review process for pesticide 

active ingredients. The Registration Review process was established under the Food Quality 

Protection Act (FQPA 1996).

2.2. Stressor Source and Distribution

2.2.1. Nature of the Chemical Stressor

FPE is a selective aryloxyphenoxypropionate herbicide used to control grass-like weeds after 

emergence. Aryloxyphenoxypropionate herbicides are systemic, i.e., taken up by the plant and 

distributed in the phloem vascular tissue, and work by inhibiting acetyl coenzyme A carboxylase, 

which effectively inhibits lipid synthesis in target plants (Martin, 2000). 

FPE is the R-enantiomer (or d-isomer) of the racemate fenoxaprop-ethyl (PC Code 128701). In 

the early 1990s, the registrant for fenoxprop-ethyl amended the registration, enriching the 

formulations to contain more FPE, as it was considered the herbicidally-active isomer. As of 2002, 

all end-use products were registered for FPE and the racemate is no longer registered by EPA. 

Older studies (prior to and during the 1990s) submitted to the Agency contained enriched isomeric 

mixtures of 85:15 d:l, 89:11 d:l, or 97:3 d:l. More recently submitted studies (2000s), however, 

contain enriched mixtures at ratios greater than 98:2 d:l. Currently registered products contain 

FPE at the 97:3 d:l mixture. The older studies submitted to the Agency and existing labels loosely 

refer to these enriched mixtures as FPE, regardless of the purity.

The chemical profile of FPE (R-enantiomer, d-isomer, of fenoxaprop-ethyl) is provided in Table 

2.1. Chemical names and structures of FPE and its degradates of concern, as they are formulated 

in standards used in submitted environmental fate studies, are provided in Table 2.1 and Appendix 

A. From the submitted fate studies, the degradation pattern of fenoxaprop-p-ethyl was well 

established: de-esterification of fenoxaprop-p-ethyl to the fenoxaprop-p acid, with subsequent 

degradation to 4-(6-chloro-2-benzoxazolyloxy)phenol, chlorobenzoxazolone, and eventually to 
-Page 8 of 116-

CO2. This de-esterification process was dependent on both abiotic and microbially-mediated 

hydrolysis (i.e., aerobic soil and aquatic metabolism). Aquatic toxicity data (Tables 3.9-3.11) for

the degradates fenoxaprop-p acid and chlorobenzoxazolone indicate that they are much less toxic 

to aquatic plants and animals than the parent FPE. Additionally, the structure of 4-(6-chloro-2-

benzoxazolyloxy)phenol) indicates that it is an intermediate between fenoxaprop-p acid and 

chlorobenzoxazolone. As toxicity data indicate that fenoxaprop-p acid and chlorobenzoxazolone 

are much less toxic than the parent FPE, EFED assumed that 4-(6-chloro-2-

benzoxazolyloxy)phenol) was also less toxic than FPE. Given this information, the evaluation of 

risks to aquatic species was limited to exposure from FPE. However, terrestrial toxicity data for 

the degradates of concern were not available for this assessment. As such, in evaluating potential 

risks to terrestrial species, estimates of exposure and risk were developed for the combined 

residues of FPE and its three degradates fenoxaprop-p acid, 4-(6-chloro-2-

benzoxazolyloxy)phenol, and chlorobenzoxazolone. This was accomplished by including both 

parent and degradate residues in the dissipation half-life used to estimate residues on terrestrial 

food items.

Table 2.1. Chemical Profile of FPE and Its Residues of Conncern.

Common name Fenoxaprop-p-ethyl

IUPAC name (R)-2[4-[(6-chloro-2-benzoxazolyl)oxy]-phenoxy]-

propanoic acid 

CAS name (R)-2-[4-[(6-chloro-1,3-

benzoxazolyl)oxy]phenoxy]propanoate ethyl

Structure

Pesticide type Herbicide

CAS number 71283-80-2

Empirical formula C18H16ClNO5 

Molecular mass 361.78 g/mol

Common Name Fenoxaprop-p acid

IUPAC name ((D+)-2-[4-(6-chloro-2-benzoxazolyloxy) phenoxy] propanoate

Structure

Common Name Chlorobenzoxazolone

IUPAC name 4-(6-chloro-2-benzoxazolyloxy) phenol

Structure

Common Name 4-(6-chloro-2-benzoxazolyloxy)phenol

IUPAC name 4-(6-chloro-2-benzoxazolyloxy)phenol

O

O

O

O

N

O

Cl OH

O

O

O

N

O

Cl NH

O

Cl

O
-Page 9 of 116-

Structure

2.2.2. Overview of Pesticide Usage

FPE is an active ingredient in several formulated products registered for post-emergent control of 

grass-like weeds (e.g., barnyardgrass, crabgrass, Italian ryegrass, etc.) in a variety of crops and 

non-crop areas. Products include Fusion®, Foxfire®, Panther®, Whip 360®, Puma 1EC®, Ricestar®, 

Puma® Ultra, WolverineTM, Acclaim Extra®, and Crabgrass Killer. Currently registered products 

contain FPE at the 97:3 d:l mixture. FPE is currently registered for use on barley, cotton, rice, 

soybeans, and wheat, and is registered for non-agricultural use on conservation reserves, 

ornamentals, rights-of-way, and turf. It is also being proposed for use on grass grown for seed. 

FPE products are flowable and are applied by ground or aerial methods; applications by 

chemigation are prohibited. Application rates vary considerably by use pattern. Multiple 

applications are allowed by most labels, with an annual maximum rate of up to 0.188 lbs a.i./A/yr

for agricultural uses and an annual maximum application rate of 0.531 lbs a.i./A/yr for nonagricultural uses. Specific use rates are discussed in Section 3.1.

A number of the currently registered FPE products also contain other active ingredients (e.g., 

fluazifop-P-butyl, dicamba acid, pinoxaden, pyrasulfotole, etc.). This evaluation is limited to 

exposure to FPE residues of concern (FPE, fenoxaprop-p acid, chlorobenzoxazolone, and 4-(6-

chloro-2-benzoxazolyloxy) phenol and non-extracted residues, as discussed in Section 3.2.1.5), 

and does not include estimated concentrations of other active ingredient residues. 

2.3. Receptors

2.3.1. Aquatic and Terrestrial Effects

The receptor is the biological entity that is exposed to the stressor (USEPA 1998). Consistent with 

the process described in the Overview Document (USEPA 2004), this risk assessment uses a 

surrogate species approach in its evaluation of FPE. Toxicity data generated from surrogate test 

species, which are intended to be representative of broad taxonomic groups, are used to extrapolate 

potential effects on a variety of species (receptors) included under these taxonomic groupings. 

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the 

available open literature are used to evaluate potential direct effects of FPE to aquatic and 

terrestrial receptors. The open literature studies are located through EPA’s database ECOTOX 

(http://cfpub.epa.gov/ecotox/), which provides a source for locating single chemical toxicity data 

for aquatic life, terrestrial plants, and wildlife. 

2.3.2. Ecosystems Potentially at Risk 

The ecosystems at risk are often extensive in scope; therefore, it may not be possible to identify 

specific ecosystems at the screening level. In general terms, terrestrial ecosystems potentially at 

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risk could include the treated site and areas immediately adjacent to the treated site that may 

receive drift, runoff, erosion, or discharged groundwater. These areas could include the treatment 

site itself, other cultivated fields, fencerows and hedgerows, meadows, fallow fields or grasslands, 

woodlands, riparian habitats, and other uncultivated areas. 

Aquatic ecosystems potentially at risk include water bodies adjacent to or downstream from treated 

areas, and can include lentic systems, i.e., ponds, lakes and impoundments (reservoirs), and lotic 

systems (streams and rivers). Aquatic ecosystems supplied by groundwater, including cave 

ecosystems and areas supplied by seeps and springs, may be at risk from compounds that leach

into the subsurface. For uses in coastal areas, aquatic habitat at potential risk includes marine and 

estuarine ecosystems. In evaluating aquatic exposure within water bodies, EFED considers the 

water column, sediment, and pore water as compartments of concern. 

2.4. Assessment Endpoints 

Assessment endpoints represent the actual environmental value that is to be protected, defined by 

an ecological entity (species, community, or other entity) and its attribute or characteristics 

(USEPA 1998). For FPE, the ecological entities include the following: birds, amphibians, reptiles, 

mammals, freshwater fish and invertebrates, estuarine/marine fish and invertebrates, terrestrial 

plants, insects, and aquatic plants and algae. The attributes assessed for each of these entities may 

include growth, survival, and reproduction. (See Table 2.3 in Section 2.6.2, the Analysis Plan, 

for further discussion).

The assessment endpoints are intended to reflect population sustainability and community 

structure within ecosystems and hence relate back to ecosystems at risk. If risks are expected for 

given species/taxa based on the screening-level assessment, then risks might be expected to 

translate to higher levels of biological organization.

2.5. Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must have a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure. The conceptual model is 

intended to provide a written description and visual representation of the predicted relationships 

between FPE, potential routes of exposure, and the predicted effects for the assessment endpoint. 

The conceptual model consists of two major components: the risk hypotheses and a conceptual 

diagram (USEPA 1998).

The conceptual model used to depict the potential ecological risk associated with the proposed and 

existing uses of FPE relies on previous assessments and the Agency’s current understanding of the 

environmental fate and ecological effects of the chemical. Consistent with the intended use of 

FPE as an herbicide, potential risk to non-target terrestrial and aquatic plants is expected. Effects 

on plants, which represent the primary producers in an ecosystem, may result in secondary effects 

on consumers. The model assumes that FPE is capable of affecting terrestrial vertebrates and 
-Page 11 of 116-

aquatic vertebrates and invertebrates, provided that environmental concentrations are sufficiently 

elevated as a result of proposed and existing uses (Figure 2.1). 

Based on the Preliminary Problem Formulation (USEPA 2007a), acute and chronic risks at the 

highest label rate of FPE are expected for non-listed and listed aquatic animals. Risks are also 

expected for non-listed and listed birds and mammals due to chronic dietary or dose-based 

exposures to FPE. Risks are expected as well for listed and non-listed species of monocots 

inhabiting dry and semi-aquatic areas based on exposures of FPE at the maximum application rate. 

Due to the potential risk from direct effects to the listed and non-listed groups of organisms 

described above, listed species in all taxa may potentially be affected indirectly due to alterations 

in their habitat (e.g., food sources, shelter, and areas to reproduce) if exposure to FPE occurs.

2.5.1. Risk Hypotheses

For FPE, the following ecological risk hypothesis is employed for the ecological risk assessment:

Given the proposed and existing uses of FPE and its environmental fate properties, there 

is possible acute and chronic exposure to non-target aquatic and terrestrial organisms. 

When used in accordance with the label, FPE may result in adverse effects upon the 

survival, growth, and reproduction of non-target aquatic and terrestrial plants and 

animals. 

 

2.5.2. Conceptual Diagram

The potential exposure pathways and effects of the proposed and existing uses of FPE are depicted 

in Figure 2.1. Solid arrows depict the most likely routes of exposure and effects; dashed lines 

depict potential routes of exposure that are not considered likely for FPE.

Application methods for proposed and existing uses of FPE involve ground and aerial applications. 

Ecological receptors that may be exposed to FPE following such applications include terrestrial 

and semi-aquatic wildlife (i.e., mammals, birds, terrestrial-phase amphibians, terrestrial 

invertebrates, and reptiles) and plants. In addition, aquatic receptors (e.g., freshwater and 

estuarine/marine fish and invertebrates, aquatic-phase amphibians, and plants) may be exposed as 

a result of movement of FPE via spray drift and runoff from the site of application. The conceptual 

framework for assessment of potential ecological risk associated with FPE is depicted in Figure 

2.1; potential endpoints, stressors, and ecological effects are identified based on this model. 

For terrestrial organisms, the primary route of exposure assessed at the screening level is the 

dietary route, via consumption of food items such as plant leaves or insects that have FPE residues 

as a result of spraying. The assessment considers exposure of non-target terrestrial invertebrates 

through oral ingestion of residues and through contact, e.g., as a result of direct deposition or spray 

drift. Direct contact and root uptake are the major routes of exposure considered for terrestrial and 

wetland plants.

Based on FPE’s vapor pressure (1.4 x 10-8torr), FPE is not expected to readily volatilize, so this

risk assessment does not take into account potential atmospheric transport in estimating 
-Page 12 of 116-

environmental concentrations. The Screening Tool for Inhalation Risk (STIR) (see Section 2.6.2), 

which compares inhalation exposure estimates to available avian and mammalian toxicity data,

also indicates that inhalation to vapor and spray drift are not of concern, so this assessment does 

not evaluate potential atmospheric transport in estimating environmental concentrations. 

Additionally, the Screening Imbibition Program (SIP) indicates that drinking water exposure is not

a potential pathway of concern for wildlife; therefore, the current assessment does not evaluate 

potential risk to wildlife through drinking water exposure. Similarly, this assessment does not 

account for possible ingestion of FPE residues by terrestrial animals via contaminated grit or 

preening activities, and does not evaluate potential uptake through dermal absorption.

For aquatic assessments, the major routes of exposure for aquatic animal species are considered to 

be through the respiratory surface (gills) or the integument. Organisms in habitats supplied 

primarily by groundwater discharge (e.g., seeps, springs) may receive a different level of exposure 

than organisms in surface rivers, streams, lakes, and impoundments. Similar to terrestrial 

organisms, exposure of aquatic organisms to FPE may also occur through ingestion of residues in 

sediment and forage. FPE is hydrophobic, with an octanol-water partition coefficient (Kow) of 

38,000 (MRID 44659601). However, bioconcentration factor (BCF) data for bluegill sunfish 

(MRID 41567707), as well as the rapid biodegradation of FPE in aerobic aquatic environments (<

1 day) to fenoxaprop-p acid (an ionic compound which is not expected to bioaccumulate), indicate 

that FPE residues, including its degradates, should not bioconcentrate in fish.

Figure 2.1. Conceptual Model Depicting Potential Risks to Non-target Species From the Use of FPE. Solid 

arrows depict the most likely routes of exposure and effects; dashed lines depict potential routes of 

exposure that are not considered likely.

Stressor

Source/

Transport

Pathways

Direct Deposition Runoff

Erosion

Leaching

(Infiltration/

Percolation

Source/

Exposure

Media

Terrestrial Plants

Terrestrial Invertebrates

Terrestrial Plants

Soil

Receiving 

Water 

Body/ 

Sediment

Groundwater

Tested

Exposure

Route

Ingestion Direct Contact

Root Uptake Gill or Integument 

Uptake

Receptors

Attribute

Changes

Terrestrial 

Vertebrates

Terrestrial Plants

Individual Animals:

 Reduced survival and/or reproduction

Aquatic Invertebrates

Aquatic Vertebrates

Individual Plants:

 Seedling emergence

 Vegetative vigor

Individual Animals:

 Reduced survival 

and/or reproduction

Plant Population:

Reduced population 

growth

Aquatic Plants

Uptake/ 

Adsorption

Spray Drift Volatilization

Atmospheric Transport

FPE and degradates of concern

Direct Contact

Terrestrial 

Invertebrates
-Page 13 of 116-

2.6. Analysis Plan 

2.6.1. Measures of Exposure

Measures of Aquatic Exposure 

Measures of exposure to aquatic animals and plants are pesticide concentrations in surface water 

and benthic sediment pore water simulated by the Pesticide Root Zone Model (PRZM v3.12.2, 

May 12, 2006a) and Exposure Analysis Modeling System (EXAMS v2.98.04.06, Apr. 2005),

coupled with the input shell pe5 (August 2007), to generate estimated environmental 

concentrations (EECs) of FPE that may occur from use on crops, typically at maximum label use 

rates. The EECs used in risk assessment are simulated 1-in-10 year return frequency “peaks”

(acute assessments) and mean concentrations over a specified duration (chronic assessments) 

generated at the modeled site, which is selected to represent a location expected to be more 

contamination-vulnerable than most locations where the crop is grown. Groundwater

concentrations of FPE were simulated using PRZM-GW (Pesticide Root Zone Model for 

Groundwater, version 1.0, August 31, 2012) and SCI-GROW (Screening Concentration in 

Groundwater, version 2.3, July 30, 2003), incorporating an analogously conservative exposure 

paradigm. For rice use, the Tier I Rice Model (version 1.0, May, 2007) was used to generate 

screening-level EECs in water within or released from a rice paddy. As screening-level EECs 

exceed aquatic criteria, the Pesticide Flooded Application Model (PFAM, version 1.05, September 

2013) was used to refine concentrations associated with rice use.

2.6.1.2. Measures of Terrestrial Exposure

Terrestrial wildlife are potentially exposed to FPE via consumption of residues on food items from

spray applications on agricultural and non-agricultural uses. For spray applications, the T-REX 

model (Terrestrial Residue EXposure model; v. 1.5.1; June 6, 2013b) is used to predict dietary 

exposure to FPE residues on foliar surfaces and insects using the Kenaga nomogram as modified 

by Fletcher (Hoerger and Kenaga 1972, Fletcher et al. 1994). In this assessment, a foliar 

dissipation half-life of 5.6 days was used for terrestrial modeling purposes, instead of the default 

35-day half-life, as suitable foliar dissipation data specific to FPE were available (MRIDs 493288-

01 through 493288-04). Estimated exposures of terrestrial insects to FPE are qualitatively 

evaluated. 

The TERRPLANT (v. 1.2.2; December 26, 2006) model is used to derive EECs relevant to 

terrestrial and wetland plants for the proposed new uses of FPE. The model assumes that default 

fractions of the intended application will be transported to an adjacent field through runoff and 

spray drift. Measures of exposure to terrestrial plants are expressed as a fraction of the mass of 

the FPE applied to a treated field.

To characterize potential non-target plant exposure from spray drift alone, Tier 1 modules in 

AgDRIFT (v. 2.1.1, December 2011) were used to estimate how far off-site spray drift exposure 

might occur at a level known to cause adverse effects in terrestrial plant toxicity studies. Labels 

for FPE have varying specifications with regard to droplet size distributions. Some indicate that 
-Page 14 of 116-

the product should be applied using nozzles and pressures that generate a Medium spray droplet 

size category. Other labels are more specific, indicating the nozzles should provide 200-350 

micron (Reg. No. 264-666) or 150-300 micron (Reg. No. 264-647) size droplets. Other products 

do not specify the droplet size distribution. For aerial applications, EFED used the American 

Society of Agricultural and Biological Engineers (ASABE, formerly ASAE) Fine-to-Medium 

droplet size category in its modeling. This size category is EFED’s default distribution when labels 

do not specify application parameters. The volume median diameter (Dv50) for the Fine-toMedium drop size distribution is 255 microns, which falls within the requirements specified on 

certain labels as discussed above. For ground applications, EFED used the ASABE Very Fine-toFine droplet size category. Again, this droplet size category is EFED’s default distribution when 

labels do not specify the application parameters for ground applications. The Dv50 for the Very 

Fine-to-Fine droplet size distribution is 175 microns, which falls within the requirements specified 

on certain labels as discussed above. 

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

an upper-bound estimate of wildlife inhalation exposure using FPE’s vapor pressure and molecular 

weight for vapor phase exposure as well as the maximum application rate and method of 

application for spray drift. STIR incorporates results from several toxicity studies including acute 

oral and inhalation rat toxicity endpoints obtained from the “six-pack” of core studies, which is a 

series of six guideline studies that are submitted to the Registration Division of the Office of 

Pesticide Programs for technical and formulated products of a pesticide (LD50 = 2,090 mg/kgbw/day, MRID 00130010; and inhalation LC50 >0.511 mg/L, MRID 00130040, respectively) as 

well as the most sensitive acute oral avian toxicity endpoint (partridge LD50 =2,000 mg/kg-bw, 

MRID 00130330). Based on the results of the STIR model (Appendix E), exposure through 

inhalation of spray drift or the vapor phase of FPE is not determined to be a potential pathway of 

concern for either avian or mammalian species on an acute exposure basis.

 

The analysis of the inhalation route in STIR does not consider that aggregation with other exposure 

pathways such as dietary, dermal, or drinking water may contribute to a total exposure that has a 

potential for effects to non-target animals. However, the Agency does consider the relative 

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

through other routes may be potentially significant contributors to wildlife risk (USEPA 2004). 

The risk characterization section (Section 4.3), discusses the impact of consideration of other 

routes of exposure that have been identified as potentially important and the degree of certainty 

associated with screening-level risk assessment conclusions. Detailed information about STIR 

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

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

The Screening Imbibition Program (SIP v.1.0, released June 15, 2010) was used to calculate an 

upper-bound estimate of wildlife drinking water exposure using FPE’s solubility (i.e., 0.7 mg/L at 

20oC, MRID 44676401), and compared to the most sensitive acute and chronic avian and 

mammalian toxicity endpoints (see Table 3.15 and 3.16, respectively). Drinking water exposure 

alone was determined not to be a potential pathway of concern for birds or mammals on either an

acute or chronic exposure basis. For a sample of the output generated by SIP v.1.0, please see 

Appendix F.
-Page 15 of 116-

2.6.2. Measures of Effect 

Measures of effect are obtained from a suite of registrant-submitted guideline studies which were 

conducted with a limited number of surrogate test species (Table 2.2). The test species are not 

intended to be representative of the most sensitive species but rather were selected based on their 

ability to thrive under laboratory conditions. Toxicity testing reported in this risk assessment 

utilizes surrogate species to represent all freshwater fish (2000+) and bird (680+) species in the 

U.S. In addition, the ECOTOX database (EPA 2009c) was searched in January 2013 to provide 

more ecological effects data for FPE. No additional data were available that indicated greater

sensitivity than those embodied in the registrant-submitted study endpoints; however, some 

information on toxicity of degradates to aquatic organisms was available for effects 

characterization.

The acute measures of effect used in this screening-level assessment are the LD50 (Lethal Dose), 

LC50 (Lethal Concentration), EC50 (Effects Concentration), and IC50 (Inhibition Concentration). 

These are measures of acute toxicity which result in 50% of the respective effect in tested 

organisms. The endpoints for chronic measures of exposure are the NOAEC (No Observed 

Adverse Effects Concentration) and the NOAEL (No Observed Adverse Effects Level). Toxicity 

studies were submitted for freshwater fish and invertebrates, estuarine/marine fish and 

invertebrates, aquatic and terrestrial plants, birds, mammals, and honey bees. The endpoints used 

for risk characterization were derived from studies which underwent review and were classified as 

“acceptable” (conducted under guideline conditions and considered to be scientifically valid) or 

“supplemental” (conditions deviated from guidelines but the results are considered to be 

scientifically valid). 

2.6.3. Integration of Exposure and Effects

The exposure and toxicity effects data are integrated in order to evaluate the risks of adverse 

ecological effects on non-target species. For the risk assessment of FPE, the risk quotient (RQ) 

method is used to compare estimated exposure and measured toxicity values. The RQ method 

involves dividing estimated environmental concentrations (EEC) by acute and chronic toxicity 

values. The resulting RQs are then compared to the Agency’s Levels of Concern (LOC) (USEPA 

2004) (Table 2.3). The LOCs are used to indicate when applications of FPE, as directed on the 

label, have the potential to cause adverse effects to non-target organisms.

Table 2.3. Agency Risk Quotient (RQ) Metrics and Levels of Concern (LOC) Per Risk Class.

Risk Class Risk Description RQ LOC

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute 

exposures

Peak EEC/LC50

1 0.5

Acute 

Restricted Use

Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use classification Peak EEC/LC50

1 0.1

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

Peak EEC/LC50

1 0.05

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures

60-day EEC/NOAEC 

(fish) 1
-Page 16 of 116-

Risk Class Risk Description RQ LOC

21-day EEC/NOAEC 

(invertebrates)

Aquatic Plants

Non-Listed Potential for effects to non-listed plants from exposures Peak EEC/LC50

1 1

Listed Potential for effects to listed plants from exposures Peak EEC/NOAEC 1

Terrestrial Animals (mammals and birds)2

Acute Potential for effects to non-listed animals from acute 

exposures

EEC/LC50 (Dietary)

0.5

EEC/LD50 (Dose)

Acute 

Restricted Use

Potential for effects to animals from acute exposures

Risks may be mitigated through restricted use classification

EEC/LC50 (Dietary)

0.2

EEC/LD50 (Dose)

Acute Listed 

Species

Listed species may be potentially affected by acute 

exposures

EEC/LC50 (Dietary)

0.1

EEC/LD50 (Dose)

Chronic Potential for effects to non-listed and listed animals from 

chronic exposures EEC/NOAEC 1

Terrestrial and Semi-Aquatic Plants

Non-Listed Potential for effects to non-target, non-listed plants from 

exposures

EEC/ EC25 1

Listed Plant Potential for effects to non-target, listed plants from 

exposures

EEC/ NOAEC

1

EEC/ EC05

1 LC50 or EC50.

2 EEC based on upper bound Kenaga nomogram values for foliar exposure.

The Agency uses the probit dose-response relationship as a tool for providing additional 

information on the potential for acute direct effects to individuals from listed species and aquatic 

animals that may indirectly affect the listed species of concern (USEPA 2004). As part of this 

evaluation, the acute RQ for listed species is presented in terms of the chance of an individual 

event (i.e., mortality or immobilization) should exposure at the EEC actually occur for a species 

with sensitivity to FPE on par with the acute toxicity endpoint selected for RQ calculation. To 

conduct this evaluation, the Agency uses the slope of the dose-response relationship available from 

the toxicity study used to establish the acute toxicity measures of effect for each taxonomic group 

that is relevant to this assessment. The individual effects probability associated with the acute RQ 

is based on the mean estimate of the slope and an assumption of a probit dose-response 

relationship. In addition to a single effects probability estimate based on the mean, upper and 

lower estimates of the effects probability are also provided to account for variance in the slope, if 

available. If no dose-response information is available to estimate a slope for this analysis, a 

default slope assumption of 4.5 is used, with lower and upper bounds of 2 to 9 (USEPA 2004). 

Individual effect probabilities are calculated based on a Microsoft® Excel spreadsheet tool 

IECV1.1 (Individual Effect Chance Model Version 1.1) developed by the U.S. EPA, OPP, 

Environmental Fate and Effects Division (June 22, 2004). The model allows for such calculations 

by entering the mean slope estimate (and the confidence bounds of that estimate) as the slope 

parameter in the spreadsheet. The desired threshold for the probability of an individual effect is 

entered as the listed species LOC or based on the calculated acute RQ, if available.
-Page 17 of 116-

3. Analysis

3.1 Use Characterization

FPE is an active ingredient in several formulated products registered for post-emergent control of 

grass-like weeds (e.g., barnyardgrass, crabgrass, Italian ryegrass, etc.) in a variety of crops and 

non-crop areas. FPE is the R-enantiomer (or d-isomer) of the racemate fenoxaprop-ethyl (PC Code 

128701). In the early 1990s, the registrant for fenoxprop-ethyl amended the registration, enriching 

the formulations to contain more FPE, as it was considered the herbicidally-active isomer. As of

2002, all end-use products were registered for FPE and the racemate is no longer registered by 

EPA. Products include Fusion® (Reg. No. 100-1059), Foxfire® (Reg. No. 100-1429), Panther®

(Reg. No. 228-716), Whip 360® (Reg. No. 264-647), Puma 1EC® (Reg. No. 264-666), Ricestar®

(Reg. No. 264-682), Puma® Ultra (Reg. No. 264-1073), WolverineTM (Reg. No. 264-1075), 

Acclaim Extra®(Reg. No. 432-950), and Crabgrass Killer (Reg. No. 72155-74). FPE is currently 

registered for use on barley, cotton, rice, soybeans, and wheat, and is registered for non-agricultural 

use on conservation reserves, ornamentals, rights-of-way, and turf. It is also being proposed for 

use on grass grown for seed. FPE products are flowable and are applied by ground or aerial 

methods; applications by chemigation are prohibited. Application rates vary considerably by use 

pattern. Multiple applications are allowed by most labels, with an annual maximum rate of up to 

0.188 lbs a.i./A/yr for agricultural uses and an annual maximum application rate of 0.531 lbs 

a.i./A/yr for non-agricultural uses. Maximum use pattern information is presented in Table 3.1. 

Ground and aerial application were selected for post-emergent weed use as these methods are

allowed under the current labels.

According to the Screening Level Usage Analysis (SLUA) provided by the Biological and 

Economic Analysis Division (BEAD) in 2012, the majority of FPE used between 2003 and 2010 

in the United States was on wheat (300,000 lbs a.i./yr), followed by barley (40,000), soybeans

(20,000), and rice (10,000). No other use pattern exceeded 500 lbs a.i./yr. The SLUA reports that 

a maximum of 25% of wheat crop acres, 30% of the barley crop acres, and 10% of the rice crop

acres were treated with FPE; all other crop acres were treated at 2.5% or less. These data do not 

include non-agricultural uses.

Table 3.1. FPE maximum application rates1.

Use

Max 

Application 

Rate per 

Application 

(lbs a.i./A)

Max # of 

Applications 

Per Season

Min 

Application 

Retreatment 

Interval 

(days)

Max 

Application 

Rate per 

Season2

(lbs a.i./A)

Max # of 

Apps Per 

Year

Max 

Application 

Rate per 

Year3

(lbs a.i./A)

Barley 0.083 1 NA 0.083 2 0.188

Conservation 

Reserve 0.1 2 14 0.128 3 0.188

Cotton 0.105 1 NA 0.105 1 0.105

Ornamental 0.173 NA 14 NA 4 0.531

Rice4 0.071

0.108

2

2

14

14

0.142

0.142

3

3

0.188

Right-of-Way 0.173 NA 14 NA 4 0.531

Soybeans 0.105

0.1

1

2

NA

14

0.105

0.128

1

3

0.105

0.188

Turf 0.173 NA 14 NA 4 0.531
-Page 18 of 116-

Use

Max 

Application 

Rate per 

Application 

(lbs a.i./A)

Max # of 

Applications 

Per Season

Min 

Application 

Retreatment 

Interval 

(days)

Max 

Application 

Rate per 

Season2

(lbs a.i./A)

Max # of 

Apps Per 

Year

Max 

Application 

Rate per 

Year3

(lbs a.i./A)

Grass grown for 

seed 0.083 NA NA 0.083 1 0.083

Wheat 0.083 1 NA 0.083 2 0.188

NA=not applicable. App=application

1 EFED assumed one growing season per calendar year for each agricultural crop.

2 Where the maximum single application rate is not evenly divisible by the maximum application rate per season, the

additional applications were reduced to meet the maximum application rate per season requirement. 

3 Where the maximum annual application rate is higher than the maximum application rate per season, the additional 

application was made using the difference between the maximum annual application rate and the maximum 

application rate per season.

4 Labels for rice use specify that the products should not be applied to fields where catfish and crayfish are 

commercially cultured. Environmental hazard statements indicate that the products are toxic to fish and aquatic 

invertebrates and that the products should not be applied directly to water or to areas where surface water is present

or to intertidal areas below the mean high water mark except as indicated in the directions for use on rice.

3.2. Exposure Characterization

3.2.1. Environmental Fate and Transport Characterization

The chemical and environmental fate characteristics of the parent compound FPE and the FPE 

residues of concern (see Section 3.2.1.5) are listed in Table 3.2 and are discussed in greater detail 

in the following sections. Half-lives for total toxic residues (TTR) in the aerobic soil, aerobic 

aquatic, and anaerobic aquatic studies in Table 3.2 include residues for FPE, fenoxaprop-p acid, 

chlorobenzoxazolone, 4-(6-chloro-2-benzoxazolyloxy) phenol).

Table 3.2. Chemical Properties and Environmental Fate Parameters of FPE residues.

Chemical/Fate Parameter Value Source (MRID)

Chemical name (D+)-ethyl-2-[4-(6-chloro-2-

benzoxazolyloxy)phenoxy]propanoate 44676401

Molecular mass 361.8 g/mol 44676401

Vapor pressure (20C) 1.4 x 10-8

torr Accession # 

412-03-0113

Water solubility (pH 5.8; 20C) 0.7 mg/L 44676401

Octanol-water partition coefficient (KOW) 38,000 44659601

Hydrolysis half-life (d) (pH 5, 25C)

FPE TTR

471232011

19.6 Stable

Hydrolysis half-life (d) (pH 7, 25C)

FPE TTR

24.6 Stable

Hydrolysis half-life (d) (pH 9, 25C)

FPE TTR

0.7 Stable

Aqueous photolysis half-life (d) (pH 7)

FPE TTR

48098502

0.95 1.22
-Page 19 of 116-

Chemical/Fate Parameter Value Source (MRID)

Aerobic soil metabolism half-life (d)2

FPE TTR Soil4

48757101 &

48868703

1.63 10 Sandy loam (1.4%)

0.31 8.7 Sandy loam (0.48%)

0.26 17.7 Loamy sand (0.46%)

0.07 12.8 Silt loam (1.9%)

Aerobic aquatic metabolism half-life (d)

FPE TTR Sediment4

0.15

0.31

59.3

126

Sand (0.8%)

Clay (2.2%) 47123208 

0.75

0.15

20.8

12.8

Sand (0.14%)

Silt loam (3.97%) 45081602

0.09

0.11

16.6

24.6

Silty clay loam (0.7-18%)

Silt loam (4.1%) 48868701

Anaerobic aquatic metabolism half-life (d)

0.22 43.4 Loam (5.95%) 45081601

1.85

2.40

101

143

Silty clay loam (0.7%)

Silt loam (4.3%) 48868702

Total residues Freundlich soil-water 

distribution coefficient (KF, L/kg)

3

; Total 

residues Freundlich organic carbon 

partitioning coefficient (KFOC, L/kgoc)

3

KF KFOC Soil4

42915001

4.1 1,767 Clay (0.2%)

6.6 807 Silty clay loam (0.8%)

9.8 383 Sandy loam (2.6%)

5.9 223 Clay loam (2.7%)

Terrestrial field dissipation half-life (d) No acceptable data

Aquatic field dissipation half-life (d) FPE TTR

43066404

<1 2.54

Fish Bioconcentration Factor

129 (edible)

1021 (non-edible)

510 (whole fish)

41567707

1 MRID 44659602, considered provisional in PF, determined to be unacceptable.

2 MRID 43400602, considered provisional in PF, determined to be unacceptable. Two newly submitted studies 

(MRIDs 48757101 and 48757102) were determined to be acceptable.

3 The Freundlich exponent that describes curvilinearity (1/n) was 1.00 in all cases. The data were insufficient to 

estimate a KF and KFOC for FPE alone, as only one concentration was analyzed.

4 % indicates percent of organic carbon in soil or sediment.

3.2.1.1. Transport and Mobility

FPE is partially soluble in water, with a limit of 0.7 mg/L at 20°C and pH 5.8 (MRID 44676401). 

The compound is not expected to volatilize significantly due to its low vapor pressure (1.4 x 10-8

torr at 20°C; Acc. # 412-03-0113).

FPE residues are considered moderately mobile. A batch equilibrium study was conducted using 

radiolabeled FPE, generating Freundlich soil-water partitioning coefficients (KF) for the combined 

radioactive residues that ranged from 4.10 to 9.77 mL/g (KFOC ranging from 223 to 1,767 mL/goc, 

MRID 42915001). The Freundlich exponent that describes curvilinearity (1/n) was 1.00 in all 

cases. Given FPE’s rapid degradation to fenoxaprop-p acid and the short equilibration times used 
-Page 20 of 116-

in the study (6-24 hours), it is expected that the mobility is representative of fenoxaprop-p acid. 

Mobility of total residues was not well explained by affinity to organic matter, as the coefficient 

of variation (CV) across four soils for KFOC (87%) was greater than that for KF (36%). The data 

were insufficient to estimate a KF and KFOC for FPE alone, as mobility for FPE was only assessed 

at one concentration.

Given this information, as well as information derived from the soil and aquatic metabolism studies 

(Section 3.2.1.2), FPE, when present in an aquatic system, is expected to remain in the water 

column, while the metabolite residues (fenoxaprop-p acid and chlorobenzoxazolone) are expected 

to form primarily within the water column, and then to diffuse into the sediments.

3.2.1.2. Degradation

Overall, FPE degrades very quickly, with half-lives on the order of one to two days, relative to its 

metabolites fenoxaprop-p acid, chlorobenzoxazolone, and 4-(6-chloro-2-benzoxazolyloxy) 

phenol. Half-lives for fenoxaprop-p acid ranged from 3.4 to 18 days in aerobic soil, up to 16 days 

in aerobic aquatic systems, and up to 200 days in anaerobic aquatic systems. Half-life estimates 

for the other two metabolites (chlorobenzoxazolone, and 4-(6-chloro-2-benzoxazolyloxy) phenol) 

could not be estimated, as the studies typically were ended before these began to decline.

FPE is hydrolyzed moderately rapidly in acidic conditions (t1⁄2 = 19.6 d at pH 5) and neutral 

conditions (t1⁄2 = 24.6 d at pH 7), and quickly in alkaline conditions (t1⁄2 = 0.7 d at pH 9; MRID 

47123201). Two major degradates were identified: fenoxaprop-p acid (AE F088406) and 

chlorobenzoxazolone (AE F054014). Fenoxaprop-p acid was the primary degradate at up to 32% 

of applied radioactivity in the hydrolysis study at pH 7 (30 days after treatment (DAT)) and 96% 

of applied radioactivity in the hydrolysis study at pH 9 (6 DAT; MRID 47123201). Both FPE and 

fenoxaprop-p acid may hydrolyze to chlorobenzoxazolone, which was observed in the hydrolysis 

study at up to 64% of the applied at pH 5 (30 DAT), 23% of the applied at pH 7 (30 DAT), and 

20% of the applied at pH 9 (30 DAT). When evaluating FPE residues (FPE, fenaxaprop-p acid,

and chlorobenzoxazolone), the combined residues were stable to hydrolysis at all pHs. Parent FPE 

also degrades quickly via aqueous photolysis, with an estimated half-life of 0.95 day at pH 7 and 

40oN latitude (MRID 48098502) and corrected for dark controls. Fenoxaprop-p acid and 4-(6-

chloro-2-benzoxazolyloxy) phenol (AE F040356) were identified as minor degradates in the 

aqueous photolysis study, reaching maxima of 2.4% (3 hours after treatment (HAT)) and 6.2% (16 

HAT) of the applied radioactivity, respectively. While chlorobenzoxazolone was not identified as 

a degradate in the aqueous photolysis study, it was not clear from the study whether the analytical 

method was capable of detecting this compound.

FPE was quickly biodegraded in aerobic soils (t1⁄2 ≤1.63 d; MRIDs 48757101 and 48868703), in 

aerobic aquatic systems (t1⁄2 <1 d; MRIDs 471233208, 45081602, and 48868701), and in anaerobic 

aquatic systems (t1⁄2 ≤2.4 d; MRIDs 45081601 and 48868702). Fenoxaprop-p acid was the major 

degradate identified in these studies, reaching maxima of 88% of the applied radioactivity at 1 

DAT in the aerobic soil studies and 96% of the applied (1 DAT) in the aerobic aquatic metabolism 

studies. Fenoxaprop-p acid was also the major degradate in the anaerobic aquatic metabolism 

study, but reached a maximum much more slowly: 88% at 7 DAT. 4-(6-chloro-2-

benzoxazolyloxy) phenol was a major degradate in the aerobic and anaerobic aquatic studies, 
-Page 21 of 116-

reaching maxima of 13.8% (28 DAT) and 15% (30 DAT), respectively. Chlorobenzoxazolone 

was not identified as a major degradate in any of the soil or aquatic metabolism studies, reaching 

a maximum of 9% of the applied radioactivity (MRIDs 48757101 and 48868701).

It should be noted that all of the biodegradation studies had high levels of non-extracted residues 

(NER, 18-69 % in all studies, except one anaerobic aquatic trial that had NER around 7%). All of 

the studies indicate a rapid breakdown of FPE to fenoxaprop-p acid. Based on results of 

chlorophenyl-radiolabeled studies, the degradation of fenoxaprop-p acid appears to coincide with 

an increase in NER, indicating that most of the radiolabeled degradation products are binding to 

the soil. Based on the phenoxy-radiolabeled studies, the degradation of fenoxaprop-p acid seems 

to coincide with an increase in the sum of NER and CO2 amounts. Chlorobenzoxazolone was the 

predominant residue detected in the harsh acid extracts conducted on the NER, suggesting that the 

NER could be composed of any of the precursor compounds (e.g., fenoxaprop-p-ethyl, 

fenoxaprop-p acid, or 4-(6-chloro-2-benzoxazolyloxy)phenol) or chlorobenzoxazolone.

To evaluate methods of extracting FPE residues from soil and sediment, a study (Appendix 3, 

MRID 48868703) was conducted using a number of different extraction techniques on FPE aged 

in soil 7 and 14 days. The study concluded that an acetonitrile/water/1% acetic acid extraction 

followed by microwave extraction with toluene provided the best results. However, of all of the 

methods evaluated, none of the tested methods achieved NER levels below 30%. As a result, it 

would seem that high levels of NER in microbially-mediated studies are unavoidable.

3.2.1.3. Field Studies

An aquatic field dissipation study was conducted with the FPE end-use product Whip® (HOE 

46360 75 EW; MRID 43066404). Whip® (7.7% a.i) was broadcast at 0.41 lbs a.i./A onto subplots 

of clay loam soil in a drained rice paddy in California with rice seedlings grown to the 1- to 4-leaf 

stage. At 4 DAT, the paddy was flooded with 6 inches of water, with the flood waters maintained

through 60 DAT. Soil samples (0-12 inch depth) were collected through 60 DAT. The limit of 

quantitation (LOQ) for residues of FPE was 10 ppb (10 μg/kg); samples containing ≥50 ppb of

FPE residues were analyzed for the individual compounds fenoxaprop-p-ethyl, fenoxaprop-p acid, 

and chlorobenzoxazolone. FPE residues (FPE, fenoxaprop-p acid, and chlorobenzoxazolone) 

dissipated in the drained soil (0-3 inch depth) with a half-life of 2.54 days, indicating that more 

than half of the FPE residues were degraded prior to flooding the field. This dissipation rate is 

within a factor of 3 of the submitted aerobic soil metabolism study half-lives. FPE residues were 

detected at a maximum concentration of 350 μg/kg (15% of the applied concentration; 0-3 inch 

depth, 0.04 DAT) and at a maximum depth of 6 inches in the soil. FPE residues were not detected 

above the LOQ (0.01 μg/L) in flood water. FPE was detected at a maximum concentration of 60 

μg/kg (0-3 inch depth; 1-2 DAT); fenoxaprop-p acid was detected at a maximum concentration of 

270 μg/kg (0-3 inch depth; 0.04 DAT); chlorobenzoxazolone was detected at a maximum 

concentration of 70 μg/kg (0-3 inch depth; 4 DAT). Maximum depths of detection for FPE parent, 

fenoxaprop-p acid, and chlorobenzoxazolone were not reported. While this study provides 

information on the dissipation of FPE residues when applied to soil pre-flooded, the study does 

not address the fate of FPE residues during post-flooded applications.
-Page 22 of 116-

3.2.1.4. Bioaccumulation in Fish

FPE is hydrophobic, with a logKow of 4.58 (Kow = 38,000, MRID 44659601). The 

bioconcentration factor (BCF) observed in bluegill sunfish fish viscera (1021x) and in edible fish 

portions (129x) and whole fish portions (510x; MRID 41567707) are in agreement with the BCF 

estimated using the Persistent Bioaccumulation Toxicity (PBT) profiler 

(http://www.pbtprofiler.net/) at 490X. Depuration of FPE residues was rapid; >90% of the 

accumulated [14C] residues were eliminated from the fish tissues by day 1 of the depuration period. 

Given FPE’s relatively short half-life in aerobic aquatic environments (< 1 day) and that once FPE 

is degraded to fenoxaprop-p acid it should not bioaccumulate (e.g., because it is an ionic 

compound), FPE residues are not expected to bioaccumulate.

3.2.1.5. Residues of Concern

FPE and its major degradates containing the 6-chloro-2-benzoxazol moiety (fenoxaprop-p acid, 

chlorobenzoxazolone, and 4-(6-chloro-2-benzoxazolyloxy) phenol) are considered by the Health 

Effects Division (HED) to be residues of concern for human dietary risk assessment (USEPA 

2013). Aquatic toxicity data (Tables 3.9-3.11) for the degradates fenoxaprop-p acid and 

chlorobenzoxazolone indicate that they are much less toxic to aquatic fish and invertebrates than 

the parent FPE. Additionally, the structure of 4-(6-chloro-2-benzoxazolyloxy)phenol) indicates 

that it is an intermediate between fenoxaprop-p acid and chlorobenzoxazolone. As toxicity data 

indicate that fenoxaprop-p acid and chlorobenzoxazolone are much less toxic to aquatic plants and 

animals than the parent FPE, EFED assumed that 4-(6-chloro-2-benzoxazolyloxy)phenol) was also 

less toxic than FPE. Given this information, the evaluation of risks to aquatic species was limited 

to exposure from FPE. However, terrestrial toxicity data for the degradates of concern were not 

available for this assessment. As such, in evaluating potential risks to terrestrial species, estimates 

of exposure and risk were developed for the combined residues of FPE and its three degradates 

fenoxaprop-p acid, 4-(6-chloro-2-benzoxazolyloxy)phenol, and chlorobenzoxazolone. This was 

accomplished by including both parent and degradate residues in the dissipation half-life used to 

estimate residues on terrestrial food items.

3.2.2. Measures of Aquatic Exposure

3.2.2.1. Aquatic Exposure Modeling

The EECs for FPE in surface water were generated based on maximum use rates (Table 3.1). 

Simulations were conducted using the PRZM and EXAMS models coupled with the input shell 

pe5.pl (August, 2007). The PRZM model simulates pesticide movement via runoff and erosion, 

and transformation that occurs in the soil. The EXAMS model simulates pesticide concentrations 

in an adjacent pond, resulting from PRZM-generated runoff and spray drift. The PRZM/EXAMS 

scenarios assume a standard 1-hectare, 2-meter depth pond (static water body) into which a 10-

hectare field drains (USEPA 2009b). A list of PRZM/EXAMS input files and sample input and 

output are included in Appendix B.

Groundwater EECs for FPE were derived using the PRZM-GW model (Pesticide Root Zone Model 

for Groundwater, version 1.0, August 31, 2012), with the GW-GUI (Graphical User Interface, 
-Page 23 of 116-

version 1.0, August 31, 2012). PRZM-GW is a one-dimensional leaching model that simulates 

concentrations of pesticides in vulnerable groundwater. The model accounts for pesticide fate in 

the crop root zone by simulating vertical pesticide transport and degradation through the soil 

profile after a pesticide is applied to an agricultural field. PRZM-GW permits the assessment of 

multiple years of pesticide application (up to 100 years) on a single site. Six standard scenarios, 

each representing a different region known to be vulnerable to groundwater contamination, are 

available for use with PRZM-GW for risk assessment purposes. In PRZM-GW simulations, each 

of these standard scenarios was used. PRZM-GW output represents pesticide concentrations in 

vulnerable groundwater located directly beneath an agricultural field, following many years of 

pesticide application.

Groundwater EECs were also derived using SCI-GROW, a regression-based model used as a 

screening tool. SCI-GROW was developed by fitting a linear model to groundwater concentrations 

with the Relative Index of Leaching Potential (RILP) as the independent variable. Groundwater 

concentrations are taken from 90-day average high concentrations from Prospective Groundwater 

studies; the RILP is a function of a pesticide’s aerobic soil metabolism and soil-water partition 

coefficient (Koc). The output of SCI-GROW represents concentrations that might be expected in 

shallow, unconfined aquifers under sandy soils. These aquifers represent groundwater that is most 

vulnerable to pesticide contamination, and which may also serve as an irrigation water source.

The EFED Tier I Rice Model (v1.0, May 8, 2007) was used to estimate aquatic exposures for direct 

water applications that represent high exposure sites for rice use. Each of these sites represents a 

shallow impoundment with a 10 cm water depth. When a pesticide is applied to the water, the 

model assumes instantaneous partitioning between the water and sediment phases according to the 

partition coefficient of the chemical (USEPA 2007b). The formula of the Tier I Rice Model v1.0 

is as follows:

EECs for 21-day and 60-day averaging periods were derived by applying the 90 percent upper 

confidence limit on the mean aerobic aquatic degradation half-life (0.41 days) to calculate the 

acute concentration, and then allowing that concentration to decrease via degradation at the same 

rate over the relevant period of time (i.e., either 21 or 60 days), before calculating the mean

concentration for the entire time period.
-Page 24 of 116-

If rice EECs exceed aquatic criteria, the Pesticide Flooded Application Model (PFAM) is used for 

refinements. PFAM (version 1.05, September 2013) simulates two linked compartments: a water 

column and a sediment zone (benthos). Each compartment is completely mixed and at internal 

equilibrium with respect to sorption of the chemical. Pesticide moves between the compartments 

via a time-limited, first-order mass-transfer process. The model accounts for hydrolysis, 

photolysis, and metabolism in water, sediment, and soil (when no water is present), sorption, and 

volatilization. Water, sediment, and pesticide may flow out of the flooded field. Changes in water 

body conditions (temperature, water levels, wind speed, etc.) and resulting changes in degradation 

rates occur on a daily time step. Pesticide application and flooding sequences are mapped onto 

the time series in 1-year cycles for the length of a simulation.

3.2.2.2. Selection of Crop Scenarios

The scenarios listed in Table 3.4 are those currently approved for Tier II surface water modeling 

which most closely represent the current and proposed uses for FPE. 

3.2.2.3. Aquatic Modeling Inputs

For aquatic exposure, modeling was conducted for parent FPE only. Half-lives used for modeling 

are presented in Table 3.2.

Application parameters were chosen based on the likely method of application at the maximum 

application rate as indicated in the label instructions. Chemical property and model input values

(Table 3.3) were chosen according to the current Input Parameter Guidance (USEPA 2009e). 

Based on EFED guidance, aerial spray of liquid formulations is expected to have 95% efficiency 

and ground spray is expected to have 99% efficiency. Using AgDRIFT, spray drift fractions were 

0.125 for aerial applications (Fine-to-Medium droplet size) and 0.06 for ground applications (Very 

Fine-to-Fine droplet size distribution, high boom application, 90th percentile). As FPE products 

are applied as a foliar application after the crop and weeds have emerged, a chemical application 

method (CAM) of 2 (i.e., chemical applied to crop foliage based on linear extrapolation of the crop 

canopy development) was used in modeling. The soil incorporation depth for all applications was 

set to 0 cm and the IPSCND parameter was set to 1, which means that any pesticide remaining on 

the foliage after harvest is assumed to be transferred directly to the soil surface at harvest. 

Appendix B contains example model output files.

Based on the existing and proposed uses for FPE, a variety of locations and PRZM/EXAMS

scenarios were run to simulate national use of the pesticide. Scenarios modeled with PRZM and 

EXAMS are indicated in Table 3.4, including application dates and the rationale for the first 

application date selection. For applications of FPE to barley/wheat, the label specifies that FPE 

can only be applied to barley/wheat once during crop season, so the second application date was 

modeled using the first day after the harvest date specified in the PRZM scenario. For applications 

of FPE to conservation reserves and soybeans (multiple applications), the label specifies that FPE 

can only be applied to conservation reserves and soybeans twice during crop season, so the third 

application date was modeled using the first day after the harvest date specified in the PRZM 

scenario.

Table 3.3. Environmental Fate Data Used for Aquatic Exposure Inputs in FPE Ecological Exposure 
-Page 25 of 116-

Assessment.

Input Parameter Value Source/comment

Molecular weight (g/mol) 361.8

Vapor pressure (torr @ 25 oC) 1.4E-08 Acc. # 412-03-0113

Solubility in water (mg/L @ 

20oC) 0.7 MRID 44676401

Henry’s Law Constant (atmm3

/mol) 9.52E-9

Calculated from vapor pressure and solubility 

where HENRY = (VAPR/760)/(SOL/MWT),

Hydrolysis half-life (t1⁄2 in days) pH 7: 24.6 MRID 47123201

Aqueous Photolysis half-life (t1⁄2

in days) 0.95 MRID 48098502

Aerobic Soil metabolism half-life 

(t1⁄2 in days) 1.2

MRIDs 48757101 and 48868703. Represents 

the 90 percent upper confidence limit on the 

mean of 4 aerobic soil metabolism half-life 

values.1

Anaerobic aquatic metabolism 

half-life (t1⁄2 in days) 2.7

MRIDs 45081601 and 48868702. Represents 

the 90 percent upper confidence limit on the 

mean of 3 anaerobic aquatic metabolism halflife values.1

Aerobic Aquatic metabolism 

half-life (t1⁄2 in days) 0.41

MRIDs 47123208, 45081602 and 48868701. 

Represents the 90 percent upper confidence 

limit on the mean of 6 aerobic aquatic 

metabolism half-life values.1

Soil partition coefficient Kd

(mL/g) 6.6

MRID 42915001. Average of four Kd values 

for TTR. Coefficient of variance for Kd data 

indicate more appropriate than Koc.

1

1 EFED input parameter guidance is located at: http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

Table 3.4. Aquatic Exposure Inputs in FPE Ecological Exposure Assessment (PRZM/EXAMS).

Use

Application 

method PE5 Scenario App Dates Comments

Barley / Wheat Aerial

CAWheatRLF_V2

NDwheatSTD

ORwheatOP1

TXwheatOP1

1/8, 6/16

5/23, 8/6

7/2, 9/8

6/18, 10/23

Apply between 2-leaf 

stage to pre-boot stage

Emergence to 60 days 

before harvest

Application set to 7 

days after emergence

Conservation Reserve2 Aerial

CAalfalfa_WirrigOP

ILalfalfaNMC

MNalfalfaOP

NCalfalfaOP

PAalfalfaOP

TXalfalfaOP

3/21, 4/4, 12/31

3/21, 4/4, 8/30

3/21, 4/4, 8/30

3/21, 4/4, 8/30

3/21, 4/4, 11/1

3/21, 4/4, 8/2

Conservation reserves 

are often seeded with 

clover, alfalfa, tall 

fescue, bromegrass, 

and ryegrass

Used same start date 

as turf

Cotton Aerial

CAcotton_WirrigSTD

MScottonSTD

NCcottonSTD

STXcottonNMC

TXcottonOP

5/8

5/8

6/8

3/23

4/23

Do not apply after boll 

set.

Application set to 7 

days after emergence
-Page 26 of 116-

Use

Application 

method PE5 Scenario App Dates Comments

Ornamental Ground

CAnurserySTD

FLnurserySTD

MInurserySTD

MInurserySTD_V2

NJnurserySTD

NurseryBSS_V2

ORnurserySTD

TNnurserySTD

3/21, 4/4, 4/18, 5/2 Used same start date 

as turf

Rice Aerial Tier 1 Rice Model NA 4-leaf stage to late 

tillering

Right-of-Way Ground CArightofwayRLF_V2

RightOfWayBSS

3/21, 4/4, 4/18, 5/2

3/21, 4/4, 4/18, 5/2

Used same start date 

as turf

Soybeans, single app

Soybeans, multiple apps Aerial MSsoybeanSTD 4/234/23, 5/7, 10/11

Apply prior to 

soybean bloom

Application set to 7 

days after emergence

Turf Ground

CATurfRLF

FLturfSTD

PAturfSTD

3/21, 4/4, 4/18, 5/2

3/21, 4/4, 4/18, 5/2

3/21, 4/4, 4/18, 5/2

Spring

Grass grown for seed Ground

CATurfRLF

FLturfSTD

PAturfSTD

3/21

3/21

3/21

Spring

1 Winter wheat scenarios, so harvest is in summer. First app date was done at 0.105 lb/A, with second app date at 0.083 lb/A.

2 As FPE can only be applied twice per season to conservation reserves (see Table 3.1), the third application date is the first date after harvest of 

the alfalfa from the scenario.

In estimating groundwater concentrations using SCI-GROW, a Koc of 595 L/kgoc (median Koc

value of four values, per EFED Input Parameter Guidance) was used and an aerobic soil half-life 

of 0.29 days (median value per EFED Input Parameter Guidance) was used. For PRZM-GW, the 

Kd, aerobic soil half-life, and hydrolysis half-life used in the PRZM/EXAMS runs (Table 3.3) 

were used, per EFED Input Parameter Guidance. Model runs in PRZM-GW were conducted using 

the highest single application rate for ornamentals, rights-of-way, and turf of 0.173 lbs a.i./A, 

applied 3 times during the year at a retreatment interval of 14 days, with a fourth application of 

0.012 lbs a.i./A. The highest annual application rate for ornamentals, rights-of-way, and turf of 

0.531 lbs a.i./A/yr was used in SCI-GROW.

3.2.2.4. Estimated Environmental Concentrations in Surface 

Water

The EECs listed in Table 3.5 reflect daily 1-in-10 year return frequency (i.e., “peak”) surface water 

concentrations based on maximum application rates for label uses of FPE. 
-Page 27 of 116-

In some cases, formulated FPE is more toxic than the technical grade active ingredient to aquatic 

organisms on both acute and chronic exposure bases. As such, peak exposure estimates from spray 

drift alone (i.e., by setting the application efficiency in the respective PRZM/EXAMS runs to 0) 

were developed to characterize the potential for acute risk to aquatic organisms from formulated 

product (Table 3.5). Chronic exposure values resulting from spray drift of the formulation were 

not calculated. As the components of a formulation are assumed to have different fate and 

transport properties (e.g., mobility, affinity to soil versus water, degradation kinetics), it is not 

possible to assess the impact of these differences on the concentration of the formulated product

as a function of time. As such, only the peak concentration for the formulated product can truly 

be estimated.

Table 3.5. FPE screening-level EECs based on FPE use.

Crop Scenario 1-in-10-year

Peak (μg/L)

Peak (μg/L)

Spray Drift 

Only1

1-in-10-year

21-day 

average 

(μg/L)

1-in-10-year

60-day 

average 

(μg/L)

Barley / 

Wheat

CAWheatRLF_V2 0.74 0.74 0.06 0.02

NDwheatSTD 0.82 0.74 0.04 0.02

ORwheatOP2 0.74 0.82 0.04 0.01

TXwheatOP2 0.81 0.74 0.04 0.01

Conservation 

Reserve

CAalfalfa_WirrigOP 0.70 0.7 0.07 0.02

ILalfalfaNMC 0.70 0.7 0.11 0.04

MNalfalfaOP 0.70 0.7 0.12 0.04

NCalfalfaOP 0.80 0.7 0.09 0.03

PAalfalfaOP 0.86 0.7 0.11 0.04

TXalfalfaOP 0.70 0.7 0.07 0.02

Cotton

CAcotton_WirrigSTD 0.74 0.74 0.04 0.01

MScottonSTD 0.78 0.74 0.04 0.01

NCcottonSTD 0.75 0.74 0.04 0.01

STXcottonNMC 0.74 0.74 0.04 0.01

TXcottonOP 0.74 0.74 0.04 0.01

Ornamental

CAnurserySTD 1.21 1.21 0.15 0.08

FLnurserySTD 1.78 1.21 0.15 0.07

MInurserySTD_V2 1.47 1.22 0.33 0.17

NJnurserySTD 1.51 1.21 0.27 0.14

NurseryBSS_V2 1.73 1.21 0.16 0.09

ORnurserySTD 1.22 1.21 0.22 0.12

TNnurserySTD 1.92 1.21 0.19 0.10

Rice Tier 1 Rice Model2

83 NA 0.91 0.32

Right-ofWay

CArightofwayRLF_V2 1.26 1.21 0.19 0.10

RightOfWayBSS 1.96 1.21 0.16 0.09

Soybeans MSsoybeanSTD 0.78 0.74 0.04 0.01

Turf CATurfRLF 1.22 1.21 0.23 0.12
-Page 28 of 116-

Crop Scenario 1-in-10-year

Peak (μg/L)

Peak (μg/L)

Spray Drift 

Only1

1-in-10-year

21-day 

average 

(μg/L)

1-in-10-year

60-day 

average 

(μg/L)

FLturfSTD 1.88 1.21 0.15 0.07

PAturfSTD 1.28 1.22 0.24 0.12

Grass grown 

for seed

CATurfRLF 0.58 0.58 0.06 0.02

FLturfSTD 0.58 0.58 0.04 0.01

PAturfSTD 0.60 0.58 0.07 0.03

1 Surface water EECs from spray drift only were calculated to better characterize potential risk to aquatic organisms 

from exposure to the end-use product (EP). The use of these values is discussed further in the Risk Description 

(Section 4.2).

2 The maximum rate per season is 0.142 lbs a.i./A, while the maximum annual rate is 0.188 lbs a.i./A. As the paddy 

water is discharged prior to the third treatment, the third treatment is not included in the estimation of the EECs.

3.2.2.5. Monitoring Data

Monitoring data are not available for fenoxaprop-ethyl, FPE or its degradates. EFED conducted a 

search of the USGS National Water Quality Assessment (NAWQA) Program database 

(http://infotrek.er.usgs.gov/nawqa_queries/index.jsp), the CDPR surface water and sediment 

database (http://cdpr.ca.gov/docs/emon/surfwtr/surfcont.htm), and the USEPA STORET 

(STOrage and RETrieval) database (http://www.epa.gov/STORET/). The NAWQA and CDPR 

databases did not list FPE or its degradates as sampled constituents. STORET listed fenoxapropp-ethyl as a constituent, but there were no records of monitoring samples from 1990 to the present

(2013).

3.2.2.6. Estimated Groundwater Concentrations 

PRZM-GW groundwater concentration estimates were greater than corresponding estimates 

generated using SCI-GROW, so they were used in this assessment. For groundwater used as 

irrigation water, the concentration of FPE estimated using PRZM-GW for application to 

ornamentals, rights-of-way, and turf (the highest application rates) is 1.97x10-10 μg/L. The 

concentration for application to ornamentals, rights-of-way, and turf estimated using SCI-GROW 

is 1.8x10-5 μg/L. All these estimates represent concentrations that might occur in shallow, 

unconfined aquifers under sandy soils (expected to be most vulnerable to pesticide contamination), 

and are thus highly conservative. 

3.2.3. Measures of Terrestrial Exposure

3.2.3.1. Ingestion of Foliar Residues by Birds and Mammals

Terrestrial wildlife exposure estimates are typically calculated for birds and mammals, 

emphasizing a dietary exposure route for uptake of pesticide active ingredients. Avian exposures 

are considered surrogates for exposures to terrestrial-phase amphibians and reptiles. For exposure 

to terrestrial organisms, such as birds and mammals, pesticide residues on food items are estimated, 

based on the assumption that organisms are exposed to pesticide residues in a given exposure use 
-Page 29 of 116-

pattern. For FPE, application methods for the registered uses include broadcast, banded, and 

directed spray of liquid formulations for all crops. 

T-REX (v. 1.5.1) is used to calculate dietary and dose-based EECs of FPE residues on food items 

for mammals and birds via proposed spray applications of the labeled uses. Input values for 

deriving EECs in T-REX are located in Table 3.6. Upper-bound Kenaga nomogram values are 

used to derive EECs for FPE exposures to terrestrial mammals and birds (Table 3.7), based on a 

1-year time period. Consideration is given to different types of feeding strategies for mammals, 

including herbivores, insectivores and granivores. Dose-based exposures are estimated for three 

weight classes of birds (20 g, 100 g, and 1000 g) and for three weight classes of mammals (15 g, 

35 g, and 1000 g).

Table 3.6. Input Parameters for Deriving Terrestrial EECs for FPE Labeled Uses (T-REX).

Proposed Use Application Rate 

(lbs a.i./A)

Minimum 

Reapplication 

Interval (days)1

Number of 

Applications

Foliar Dissipation 

Half-Life (days)

Barley, wheat 0.083, 0.105 159 2

5.62

Conservation reserve 0.1, 0.028, 0.06 14, 271 3

Cotton 0.105 NA 1

Grass grown for seed 0.083 NA 1

Ornamental, right-of-way, 

turf

0.173, 0.173, 

0.173, 0.012 14 4

Rice, Scenario 1 0.071, 0.071, 0.046 14 3

Rice, Scenario 2 0.108, 0.034, 0.046 14 3

Soybean, Scenario 1 0.105 NA 1

Soybean, Scenario 2 0.1, 0.028, 0.06 14, 157 3

1 TREX v 1.5.1 allows for the input of applications with varying retreatment intervals. Where multiple values are 

entered, the second interval represents an application that occurs outside the growing season, but still presents the 

potential for exposure.

2 Developed from residues dissipation studies (MRIDs 493288-01 through 493288-04, DP Barcode 418908).

Differences in exposures between ground and aerial applications are not assessed with the current 

model. Therefore, terrestrial risk conclusions for the registered and proposed uses apply to both 

ground and aerial exposures resulting from application of FPE. Uncertainties in the terrestrial 

EECs are primarily associated with a lack of data on pesticide spray interception and subsequent 

dissipation from foliar surfaces. Foliar dissipation data from MRIDs 493288-01 through 493288-

04 (DP Barcode 418908) were reviewed and a dissipation half-live of 5.6 days was used for 

terrestrial modeling purposes. It should be noted that this dissipation half-life value includes 

degradate residues and therefore EECs derived in the T-REX model are considered as a TTR 

approach. An example of output from the T-REX model is provided in Appendix C.
-Page 30 of 116-

Table 3.7. T-REX Calculated EECs as Food Residues for Terrestrial Animals from FPE Labeled Uses.

Food Type

Dietary 

Based

(ppm)

(mammals 

and birds)

Dose Based

(mg/kg-bw)

(birds)

Dose Based

(mg/kg-bw)

(mammals)

All Size 

Classes

Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Barley, wheat

Herbivores/Insectivores

Short grass 25.20 28.70 16.37 7.33 24.03 16.61 3.85

Tall grass 11.55 13.15 7.50 3.36 11.01 7.61 1.76

Broadleaf plants 14.18 16.14 9.21 4.12 13.51 9.34 2.17

Fruits/pods/seeds 1.58 1.79 1.02 0.46 1.50 1.04 0.24

Arthropods 9.87 11.24 6.41 2.87 9.41 6.50 1.51

Granivores

Seeds N/A 0.40 0.23 0.10 0.33 0.23 0.05

Conservation Reserve

Herbivores/Insectivores

Short grass 24.00 27.33 15.59 6.98 22.88 15.81 3.67

Tall grass 11.00 12.53 7.14 3.20 10.49 7.25 1.68

Broadleaf plants 13.50 15.38 8.77 3.93 12.87 8.90 2.06

Fruits/pods/seeds 1.50 1.71 0.97 0.44 1.43 0.99 0.23

Arthropods 9.40 10.71 6.10 2.73 8.96 6.19 1.44

Granivores

Seeds N/A 0.38 0.22 0.10 0.32 0.22 0.05

Cotton

Herbivores/Insectivores

Short grass 25.20 28.70 16.37 7.33 24.03 16.61 3.85

Tall grass 11.55 13.15 7.50 3.36 11.01 7.61 1.76

Broadleaf plants 14.18 16.14 9.21 4.12 13.51 9.34 2.17

Fruits/pods/seeds 1.58 1.79 1.02 0.46 1.50 1.04 0.24

Arthropods 9.87 11.24 6.41 2.87 9.41 6.50 1.51

Granivores

Seeds N/A 0.40 0.23 0.10 0.33 0.23 0.05

Grass grown for seed

Herbivores/Insectivores

Short grass 19.92 22.69 12.94 5.79 18.99 13.13 3.04

Tall grass 9.13 10.40 5.93 2.65 8.70 6.02 1.39

Broadleaf plants 11.21 12.76 7.28 3.26 10.68 7.38 1.71

Fruits/pods/seeds 1.25 1.42 0.81 0.36 1.19 0.82 0.19

Arthropods 7.80 8.89 5.07 2.27 7.44 5.14 1.19

Granivores

Seeds N/A 0.32 0.18 0.08 0.26 0.18 0.04

Ornamental, right-of-way, turf

Herbivores/Insectivores

Short grass 50.16 57.12 32.57 14.58 47.82 33.05 7.66

Tall grass 22.99 26.18 14.93 6.68 21.92 15.15 3.51

Broadleaf plants 28.21 32.13 18.32 8.20 26.90 18.59 4.31

Fruits/pods/seeds 3.13 3.57 2.04 0.91 2.99 2.07 0.48

Arthropods 19.64 22.37 12.76 5.71 18.73 12.94 3.00

Granivores

Seeds N/A 0.79 0.45 0.20 0.66 0.46 0.11
-Page 31 of 116-

Food Type

Dietary 

Based

(ppm)

(mammals 

and birds)

Dose Based

(mg/kg-bw)

(birds)

Dose Based

(mg/kg-bw)

(mammals)

All Size 

Classes

Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Rice, Scenario 1

Herbivores/Insectivores

Short grass 20.05 22.84 13.02 5.83 19.12 13.21 3.06

Tall grass 9.19 10.47 5.97 2.67 8.76 6.06 1.40

Broadleaf plants 11.28 12.85 7.33 3.28 10.75 7.43 1.72

Fruits/pods/seeds 1.25 1.43 0.81 0.36 1.19 0.83 0.19

Arthropods 7.85 8.94 5.10 2.28 7.49 5.18 1.20

Granivores

Seeds N/A 0.32 0.18 0.08 0.27 0.18 0.04

Rice, Scenario 2

Herbivores/Insectivores

Short grass 25.92 29.52 16.83 7.54 24.71 17.08 3.96

Tall grass 11.88 13.53 7.72 3.45 11.33 7.83 1.82

Broadleaf plants 14.58 16.61 9.47 4.24 13.90 9.61 2.23

Fruits/pods/seeds 1.62 1.85 1.05 0.47 1.54 1.07 0.25

Arthropods 10.15 11.56 6.59 2.95 9.68 6.69 1.55

Granivores

Seeds N/A 0.41 0.23 0.10 0.41 0.23 0.10

Soybean, Scenario 1

Herbivores/Insectivores

Short grass 25.20 28.70 16.37 7.33 24.03 16.61 3.85

Tall grass 11.55 13.15 7.50 3.36 11.01 7.61 1.76

Broadleaf plants 14.18 16.14 9.21 4.12 13.51 9.34 2.17

Fruits/pods/seeds 1.58 1.79 1.02 0.46 1.50 1.04 0.24

Arthropods 9.87 11.24 6.41 2.87 9.41 6.50 1.51

Granivores

Seeds N/A 0.40 0.23 0.10 0.33 0.23 0.05

Soybean, Scenario 2

Herbivores/Insectivores

Short grass 24.00 27.33 15.59 6.98 22.88 15.81 3.67

Tall grass 11.00 12.53 7.14 3.20 10.49 7.25 1.68

Broadleaf plants 13.50 15.38 8.77 3.93 12.87 8.90 2.06

Fruits/pods/seeds 1.50 1.71 0.97 0.44 1.43 0.99 0.23

Arthropods 9.40 10.71 6.10 2.73 8.96 6.19 1.44

Granivores

Seeds N/A 0.38 0.22 0.10 0.32 0.22 0.05

3.2.3.2. Runoff and Spray Drift to Terrestrial and Semi-Aquatic 

Plants

Exposure of non-target terrestrial and semi-aquatic (wetland) plant species is estimated using 

OPP’s TERRPLANT (v. 1.2.2) model. Loading via spray drift to dry, non-target, adjacent areas 

is assumed to occur from one acre of treated land to one acre of the non-target area. Runoff is also 

expected to be a source of pesticide loading to non-target areas. TERRPLANT calculates EECs 

as a function of application rate, solubility, and default assumptions regarding spray drift. The 
-Page 32 of 116-

spray drift assumptions are the same as those used in the aquatic modeling: 6% of the application 

rate (mass per acre) for ground spray applications and 12.5% for aerial spray applications (USEPA 

2006b). The EECs for terrestrial and semi-aquatic plants for a single application of FPE at the 

maximum labeled rates for representative uses are presented in Table 3.8 (see example output in 

Appendix E).

Table 3.8. EECs for Terrestrial and Semi-Aquatic Plants Near FPE Use Areas.

Crop

Single Max. 

Application 

Rate

(lbs a.i./A)

EECs (lbs a.i./A)

Semi-Aquatic Areas 

(Total) Spray Drift Dry Areas (Total)

Ground 

spray

Aerial 

spray

Ground 

spray1

Aerial 

spray

Ground 

spray1

Aerial 

spray

Barley, wheat, 

cotton, soybean 0.105 0.017 0.024 0.006 0.013 0.007 0.014

Conservation 

reserve

0.1 0.016 0.023 0.006 0.013 0.007 0.014

Grass grown for 

seed 0.083 0.013 N/A 0.005 N/A 0.006 N/A

Ornamental, rightof-way, turf 0.173 0.028 N/A 0.010 N/A 0.012 N/A

Rice 0.108 0.017 0.024 0.006 0.014 0.008 0.015

3.3. Ecological Effects Characterization 

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

the TGAI, transformation products, and specified formulations. The ecotoxicity data for FPE and 

its associated products have been reviewed previously in a Preliminary Problem Formulation for 

Registration Review (USEPA 2007). In addition, many aquatic and terrestrial organism toxicity 

studies with TGAI, transformation products, or formulated FPE were submitted after the 

Preliminary Problem Formulation and are included in this assessment. The most sensitive 

endpoints used for risk assessment are summarized briefly in Sections 3.3.1 and 3.3.2. Ecotoxicity 

data submitted for FPE degradates on aquatic organisms indicate that these degradates are 

generally equally or less toxic than parent FPE.

Fenoxaprop-ethyl (PC Code: 128701) is a chemical with a similar structure to FPE that was used 

in previous EFED risk assessments and in the preliminary problem formulation for the purpose of

bridging toxicity information for FPE in cases where data gaps exist. Since many new aquatic and 

terrestrial organism toxicity studies were recently submitted for FPE, toxicity data for fenoxapropethyl is only bridged with FPE in this assessment to fill the few remaining data gaps (freshwater 

invertebrates [acute]; estuarine/marine mollusks [acute]; mammals [chronic]. For purposes of 

comparison, all available toxicity data for fenoxaprop-ethyl are still presented in this assessment, 

even if they are not used for risk estimation. The use of fenoxaprop-ethyl toxicity data to represent 

FPE is considered appropriate since FPE is the R-enantiomer enrichment of fenoxaprop-ethyl, 

which contains a combination of both R- and S-enantiomers. There is some uncertainty in this 
-Page 33 of 116-

bridging strategy since the influence of the S-enantiomer on toxicity of fenoxaprop-ethyl is 

unknown.

The results of a 2013 review of the Ecological Incident Information System (EIIS) are described 

in Section 3.3.3 (USEPA 2013). A search of the ECOTOX database in January 2013 yielded no 

new data from suitable studies with more sensitive toxicity endpoints than those obtained from 

registrant-submitted guideline studies described below; however, some information on toxicity of 

degradates to aquatic organisms were available for effects characterization.

3.3.1. Aquatic Toxicity Assessment

3.3.1.1. Toxicity to Aquatic Vertebrates

A summary of data on toxicity to aquatic vertebrates for technical grade FPE, formulated products, 

and FPE transformation products is presented in Table 3.9. 

On an acute exposure basis, FPE is highly toxic to freshwater fish, with LC50 values ranging from 

0.46 to 0.58 mg a.i./L across tested species (not including data from fenoxaprop-ethyl). Only a 

single estuarine/marine fish acute study was provided for fenoxaprop-ethyl on the sheepshead 

minnow (Cyprinodon variegatus; MRID 00163779), which resulted in an LC50 >1 mg a.i./L

suggesting that the toxicity of the compound may be limited by its solubility. 

In a recently submitted 33-day early life-stage study (MRID 48417901) with the fathead minnow 

(Pimephales promelas), fertilized eggs were exposed to total mean-measured concentrations of 

fenoxaprop-p-ethyl and fenoxaprop-p acid degradate (total residues) of 0.016, 0.027, 0.044, 0.071, 

and 0.11 mg a.i./L under flow-through conditions. Mean hatching success/embryo survival ranged 

between 71.4 and 80.4%, and showed no significant difference at any test level compared to the 

control. Post-hatch (juvenile) survival was significantly (p<0.05) lower at the two highest 

treatment concentrations (90 and 18.3% mean survival at 0.071 and 0.11 mg a.i./L), as compared 

to the control, resulting in a study NOAEC of 0.044 mg a.i./L. There was a statistically significant

(p<0.05) decrease in length and dry weights in comparison to the control at the highest test level 

of 0.11 mg a.i./L, but due to the observed high mortality in this test level (81.7 %) these results 

were excluded from the NOAEC/LOAEC determination. No significant decrease in standard 

length or dry weight was evident at any other test level when compared to the control.

No chronic estuarine/marine fish toxicity data are available for either FPE or fenoxaprop-ethyl. In 

order to derive a chronic estuarine/marine fish toxicity endpoint for risk assessment, an acute-tochronic ratio (ACR) based upon data from the fathead minnow was applied to the sheepshead 

minnow acute toxicity endpoint (ACR [fathead minnow] = 0.50 [acute]/0.044 [chronic] = 11.4; 1 

mg a.i./L [sheepshead minnow acute]/11.4 [fathead minnow ACR] = 0.088 mg a.i./L [sheepshead 

minnow chronic toxicity value]). It should be noted that the sheepshead minnow acute toxicity 

value is a “greater than value,” and therefore the ACR-derived chronic value is considered a 

conservative toxicity estimate to be used for risk characterization purposes only, and not for 

calculating RQs. 
-Page 34 of 116-

Degradates or formulations do not appear to be substantially (more than an order of magnitude) 

more toxic to freshwater fish as compared to FPE TGAI on an acute exposure basis. Moreover, 

the degradates fenoxaprop-p acid (AE F088406) and chlorobenzoxazolone (AE F054014) appear

to be several orders of magnitude less toxic to fish on an acute exposure basis.

Table 3.9. Summary of Available Acute and Chronic Toxicity Data for Aquatic Vertebrates Exposed to FPE, 

Degradates, and Formulations

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Freshwater Vertebrates

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

FPE

(95.6%)

LC50

(96 hours)

0.46*

(highly toxic)

42009604

(Acceptable)

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

FPE

(95.6%)

LC50

(96 hours)

0.58

(highly toxic)

42009605

(Acceptable)

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

Formulation:

FPE + HOE 

107892

(safener)

(12.5%)

LC50

(96 hours)

0.45

(highly toxic)

47333428

(Supplemental)

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

Degradate:

Fenoxaprop-p

acid

[AE F088406]

(93.8%)

LC50

(96 hours)

>68.8

(slightly toxic)

47333413

(Acceptable)

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

Degradate:

Chlorobenzoxaz

olone [AE 

F054014]

(99.7%)

LC50

(96 hours)

>10

(slightly toxic)

44801503

(Supplemental)1

Oncorhynchus 

mykiss

(Rainbow trout)

Acute

(Survival)

Degradate:

AE F096918

(>99%)

LC50

(96 hours)

318 

[227-445]

(practically nontoxic)

47333418

(Supplemental)

Oncorhynchus 

mykiss

(Rainbow trout)

Sub-chronic

(Parental 

survival)

Degradate:

Fenoxaprop-p 

acid

[AE F088406]

(97.4%)

NOAEC

LOAEC

(28 day)

1.8

3.1

47333414

(Supplemental)

Oncorhynchus 

mykiss

(Rainbow trout)

Sub-chronic

(No effects 

observed)

Degradate:

AE F096918

(>99%)

NOAEC

LOAEC

(28 day)

31

>31

47333419

(Supplemental)

Salmo trutta

(Brown trout)

Acute

(Survival)

Fenoxapropethyl

(96%)

LC50

(96 hours)

0.48 

[0.45-0.52]

(highly toxic)

47333418

(Supplemental)

Lepomis 

macrochirus

(Bluegill sunfish)

Acute

(Survival)

FPE

(95.6%)

LC50

(96 hours)

0.58

(highly toxic)

42009603

(Acceptable)
-Page 35 of 116-

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Lepomis 

macrochirus

(Bluegill sunfish)

Acute

(Survival)

Fenoxapropethyl

(95.8%)

LC50

(96 hours)

0.31

[0.26-0.35]

(highly toxic)

00130337

(Acceptable)

Lepomis 

macrochirus

(Bluegill sunfish)

Acute

(Survival)

Formulation:

FPE + HOE 

107892 

(safener)

(12.5%)

LC50

(96 hours)

0.28 

[0.23-0.33]

47333431

(Supplemental)

Lepomis gibbosus

(Pumpkinseed

sunfish)

Acute

(Survival)

Fenoxapropethyl

(96%)

LC50

(96 hours)

0.36 

[0.32-0.41]

(highly toxic)

00130338

(Acceptable)

Pimephales 

promelas (Fathead 

minnow)

Acute

(Survival)

FPE

(94.5%)

LC50

(96 hours)

0.50

[0.42-0.61]

(highly toxic)

48492501

(Acceptable)

Pimephales 

promelas (Fathead 

minnow)

Chronic, early 

life-stage

(Post-hatch 

survival)

FPE

(94.5%)

NOAEC

LOAEC

(33 days)

0.044*

0.071

48417901

(Acceptable)

Estuarine/Marine Vertebrates

Cyprinodon 

variegatus

(Sheepshead 

minnow)

Acute

(Survival)

Fenoxapropethyl

(96.5%)

LC50

(96 hours)

>1

(moderately 

toxic)

00163779

(Supplemental)

Cyprinodon 

variegatus

(Sheepshead 

minnow)

Chronic, early 

life-stage

(ACR)

N/A NOAEC 0.088 ACR-derived 

toxicity value

*Represents the most sensitive toxicity endpoint to be used in RQ calculations

1 Classification is based on preliminary study review which will be finalized before completion of the final risk 

assessment.

3.3.1.2. Toxicity to Aquatic Invertebrates

A summary of data on the toxicity of FPE, formulations, and transformation products to aquatic 

invertebrates is provided in Table 3.10. 

On an acute exposure basis, the toxicity of FPE to freshwater invertebrates is non-definitive, with 

a EC50 value of >1.1 mg a.i./L (not including data from fenoxaprop-ethyl), and highly toxic to 

estuarine/marine invertebrates with EC50/LC50 values ranging 0.11 mg a.i./L (not including data 

from fenoxaprop-ethyl). Since the acute toxicity endpoint for Daphnia magna exposed to FPE is 

non-definitive (EC50 >1.1 mg a.i./L), the daphnid endpoint for fenoxaprop-ethyl (EC50 = 3.18 mg 

a.i./L) will be used for RQ calculations in this assessment, while the endpoint for FPE will be used 

in risk characterization.

Freshwater invertebrate (D. magna) toxicity endpoints for FPE and two degradates (fenoxaprop-p 

acid [AE F088406] and AE F096918) are all non-definitive (i.e., greater than the highest 

concentration tested), although much higher concentrations were tested on the degradates relative
-Page 36 of 116-

to FPE due to FPE’s lower solubility.

1 Consequently, there is no evidence suggesting that either 

of these degradates are more toxic than FPE on an acute exposure basis. AE F054014 

(chlorobenzoxazolone) was found to be moderately toxic to D. magna (EC50=6.6 mg a.i./L), but 

the toxicity of this degradate cannot be compared to the parent since FPE was only tested up to 1 

mg a.i./L. A single acute toxicity test conducted with a formulation (FPE + HOE 107892) on D. 

magna suggests that this formulation, which also contains the plant safener HOE 107892, is at 

least two-fold more toxic to freshwater invertebrates than FPE technical.

In a 21-day chronic life cycle study (MRID 47332706) with D. magna, individuals were exposed 

to nominal concentrations of FPE of 0.01, 0.032, 0.1, 0.32, and 1.0 mg/L (not adjusted for purity)

under static renewal conditions. Time-weighted-average (TWA) concentrations were 0.0072, 

0.068, and 0.76 mg/L for the nominal 0.01, 0.1, and 1.0 mg/L levels, respectively. The 21-day 

NOAEC, based on an adverse effect on reproduction (number of dead larvae per surviving adult) 

at the highest treatment level, was estimated to be 0.23 mg/L (estimated using average TWA 

recoveries of 72% of nominal for the lowest, middle, and highest concentrations). Cumulative 

immobilization of Daphnia ranged from 2.5 to 12.5% for all control and treatment levels, with no

statistically significant differences observed. At the highest concentration of 0.76 mg/L (TWA), 

the average number of dead larvae per surviving adult was 3.35, which was statistically different 

compared to the negative and solvent control groups. No statistically-significant differences from 

controls were observed regarding the total number of larvae per surviving adult at any treatment 

level. The study did not measure adult growth (length) endpoints, which are required for this test.

Life cycle studies of D. magna performed with FPE formulations showed five to 100 times greater 

sensitivity (NOAEC range: 0.0023-0.042 mg a.i./L) as compared to a TGAI study with FPE 

(NOAEC = 0.23 mg a.i./L). The higher toxicity exhibited by the formulations does not appear to 

be driven by the co-formulated active ingredient mefenpyr-diethyl (PC Code 811800; a plant 

safener) since three studies with FPE combined with mefenpyr-diethyl resulted in lower toxicity

(i.e., less sensitive) as compared to a formulation (HOE 046360 OH EW07 A209) with FPE alone

(Table 3.10). In addition, an acute study with Daphnia conducted with mefenpyr-diethyl TGAI 

(MRID 43972208; EC50=52 mg a.i./L) does not provide evidence that the safener is more toxic to 

freshwater invertebrates as compared to FPE (Daphnia EC50 >1.1 mg a.i./L). Therefore, the 

increased toxicity of the formulation is likely a result of inert ingredients included in the 

formulation.

In a 28-day chronic life cycle study (MRID 44786802) with mysid shrimp (Americamysis bahia),

individuals were exposed to mean-measured concentrations of FPE of 0.011, 0.033, 0.077, 0.15, 

and 0.33 mg a.i./L. Sublethal effects including some initial lethargy and erratic swimming were 

observed in mysids at the 0.15 mg a.i./L concentration on days 4, 5, and 6 of the study. A 10% 

reduction in dry weight at the 0.033 mg a.i./L test level was the most sensitive endpoint, resulting 

in a NOAEC of 0.011 mg a.i./L. Significant effects (p<0.05) in number of young per female, mean 

total length, and mean wet weight were observed at the next highest concentration (0.077 mg 

a.i./L).

 

1 Solubility of fenoxaprop-p [AE F088406] and AE F096918 are 270 and 190,000 mg/L, respectively.
-Page 37 of 116-

Table 3.10. Summary of Acute and Chronic Toxicity Data for Aquatic Invertebrates Exposed to FPE, 

Degradates, and Formulations.

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Freshwater Invertebrates

Daphnia magna

(Water flea)

Acute

(Immobility)

FPE

(88.1%)

EC50

(48 hours)

>1.1

(moderately 

toxic)

44664002

(Supplemental)

Daphnia magna

(Water flea)

Acute

(Immobility)

Fenoxapropethyl

(96%)

EC50

(48 hours)

3.18*

[1.79-7.36]

(moderately 

toxic)

00130342

(Acceptable)

Daphnia magna

(Water flea)

Acute

(Immobility)

Formulation:

FPE + HOE 

107892

(safener)

(12.5%)

EC50

(48 hours)

0.52

[0.42-0.65]

47333429

(Supplemental)

Daphnia magna

(Water flea)

Acute

(Immobility)

Degradate:

Fenoxaprop-p

acid

[AE F088406]

(95.6%)

EC50

(48 hours)

>32

(slightly toxic)

47333415

(Acceptable)

Daphnia magna

(Water flea)

Acute

(Immobility)

Degradate:

Fenoxaprop-p

acid

[AE F088406]

EC50

(48 hours)

14.2

(slightly toxic)

ECOTOX Ref# 

158031

(Supplemental)

Daphnia magna

(Water flea)

Acute

(Immobility)

Degradate:

Chlorobenzoxaz

olone [AE 

F054014]

(99.7%)

EC50

(48 hours)

6.6

(moderately 

toxic)

44801505

(Supplemental)

1

Daphnia magna

(Water flea)

Acute

(Immobility)

Degradate:

Chlorobenzoxaz

olone [AE 

F054014]

EC50

(48 hours)

8.2

(moderately 

toxic)

ECOTOX Ref# 

158031

(Supplemental)

Daphnia magna

(Water flea)

Acute

(Immobility)

Degradate:

AE F096918

(>99%)

EC50

(48 hours)

>185.6

(practically nontoxic)

47333420

(Acceptable)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(number of 

living 

offspring per 

surviving 

adult)

FPE

(89.5%)

NOAEC

LOAEC

(21 day)

0.23*

0.76

47332706

(Supplemental)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(offspring 

production)

Fenoxapropethyl

(97%)

NOAEC

LOAEC

(21 day)

0.56

1.0

47332705

(Supplemental)
-Page 38 of 116-

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(age at first 

brood release)

Formulation: 

AE F046360 –

24 EW14 A717

(7.28% FPE; 

7.60% 

mefenpyrdiethyl)

NOAEC

LOAEC

(21 day)

0.042

0.088

47332701

(Supplemental)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(number of 

living per 

female)

Formulation:

Puma® SB 69-

75 EW (6.81% 

FPE;

7.18% 

mefenpyrdiethyl)

NOAEC

LOAEC

(21 day)

0.0081

0.016

47332702

(Supplemental)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(number of 

living 

offspring per 

surviving 

adult)

Formulation:

HOE 046360 24 

EW14 A703 

(7.0% FPE;

7.2% mefenpyrdiethyl)

NOAEC

LOAEC

(21 day)

0.0074

0.013

47332703

(Supplemental)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(number of 

living 

offspring per 

surviving 

adult)

Formulation:

HOE 046360 

OH EW07 

A209

(7.2% FPE)

NOAEC

LOAEC

(21 day)

0.0023

0.0072

47332704

(Supplemental)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(number of 

dead offspring 

produced)

Degradate:

Fenoxaprop-p 

acid

[AE F088406]

(97.4%)

NOAEC

LOAEC

(21 day)

0.34

1.0

47332416

(Acceptable)

Daphnia magna

(Water flea)

Chronic, life 

cycle

(length)

Degradate:

AE F096918

(>99%)

NOAEC

LOAEC

(21 day)

<0.31

0.31

47332421

(Supplemental)

Procambarus 

simulans

(Crayfish)

Acute

(Survival)

Fenoxapropethyl

(96.5%)

LC50

(96 hours)

1.1

[0.74-1.5]

(moderately 

toxic)

00154343

(Supplemental)

Estuarine/Marine Invertebrates

Americamysis 

bahia (Mysid 

shrimp)

Acute

(Survival)

FPE

(89.5%)

LC50

(96 hours)

0.11*

(highly toxic)

42009607

(Acceptable)

Americamysis 

bahia (Mysid 

shrimp)

Acute

(Survival)

Fenoxapropethyl

(96.5%)

LC50

(96 hours)

0.098

[0.068-0.15]

(very highly 

toxic)

00163777

(Acceptable)
-Page 39 of 116-

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Americamysis 

bahia (Mysid 

shrimp)

Acute

(Survival)

Fenoxapropethyl

(96.8%)

LC50

(96 hours)

0.11

(highly toxic)

42009608

(Acceptable)

Americamysis 

bahia (Mysid 

shrimp)

Chronic, life 

cycle

(dry weight)

FPE

(88.1%)

NOAEC

LOAEC

(28 days)

0.011*

0.033

44786802

(Acceptable)

Crassostrea 

virginica (Eastern 

oyster)

Acute

(Immobility)

Fenoxapropethyl

(96.5%)

EC50

(48 hours)

0.25

[0.11-0.35]

(highly toxic)

00163775

(Supplemental)

Mercenaria 

mercenaria

(Quahog clam)

Acute

(Immobility)

Fenoxapropethyl

(96.5%)

EC50

(48 hours)

0.20

[0.068-0.15]

(highly toxic)

40404702

(Acceptable)

* Represents the most sensitive toxicity endpoint to be used in RQ calculations

1 Classification is based on preliminary study review which will be finalized before completion of the final risk 

assessment.

3.3.1.3. Toxicity to Aquatic Plants

A summary of the toxicity profile for FPE, formulations, and transformation products for aquatic 

plants are located in Table 3.11. 

In 14-day toxicity study with vascular aquatic plant duckweed, Lemna gibba (MRID 48566202)

exposed to FPE, no adverse effects on frond number were observed up to the highest concentration 

tested (3 mg a.i./L). In a 7-day test with a formulation (Puma® 120) containing FPE and the active 

ingredient mefenpyr-diethyl (MRID 47333425), lower EC50 and NOAEC values (higher toxicity) 

were estimated as compared to the 14-day test with FPE alone. 

Aquatic toxicity tests with nonvascular algae and cyanobacteria species exposed to FPE resulted 

in EC50 and NOAEC values ranging from 0.43 to 2.5 and 0.027 to 1.5 mg a.i./L, respectively. In 

tests with the freshwater diatom, N. pelliculosa (MRID 48566202), and the cyanobacterium,

Anabaena flos-aquae (MRID 48566202), no effects on cell density, growth rate, or biomass were 

observed up to the highest concentrations tested. Definitive NOAEC values were not obtained for 

marine diatoms and cyanobacteria, indicating uncertainty in the effects of FPE to these aquatic 

nonvascular plants. Toxicity tests with FPE degradates (MRIDs 47333417 and 47333422) suggest 

that fenoxaprop-p acid, AE F054014, AE F096918 do not appear to be as toxic to green algae as 

compared to FPE. Conversely, a test with a formulation containing FPE and HOE 107892 (MRID 

47333427) resulted in an EC50 that was approximately four times lower (more sensitive) than 

technical grade FPE for green algae, while the NOAEC for the formulation study was more than 

two-fold higher than the TGAI study.
-Page 40 of 116-

Table 3.11. Summary of Toxicity Data for Vascular and Nonvascular Aquatic Plants Exposed to FPE.

Species

(Common Name)

Measure of 

Effect

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

MRID

(Study 

Classification)

Lemna gibba

(Duckweed)

% Inhibition FPE

(88.1%)

EC50

(14 days) >3 44664003

NOAEC (Supplemental)

(14 days) 3*

Lemna gibba

(Duckweed)

% Inhibition

Formulation:

Puma® 120

(78% FPE; coformulated with 

mefenpyrdiethyl)

EC50

(7 days)

1.7

[1.4-2.0]

47333425

NOAEC (Supplemental)

(7 days) 0.094

Raphidocelis 

subcapitata

(Green algae)

% Inhibition FPE

(97.4%)

EC50

(120 hours) 0.43*

42009609

NOAEC (Supplemental)

(120 hours) 0.027*

Raphidocelis 

subcapitata

(Green algae)

% Inhibition

Fenoxapropethyl

(96.8%)

EC50

(120 hours) 0.65 42009610

NOAEC (Acceptable)

(120 hours) 0.10

Raphidocelis 

subcapitata

(Green algae)

% Inhibition

Degradate:

Fenoxaprop-p

(95.6%)

EC50

(120 hours)

44

[41-47] 47333417

NOAEC (Supplemental)

(120 hours) 18

Raphidocelis 

subcapitata

(Green algae)

% Inhibition

Degradate:

Chlorobenzoxaz

olone [AE 

F054014]

(99.7%)

EC50

(96 hours) 7.5 44801501(Supplemental)1

Raphidocelis 

subcapitata

(Green algae)

% Inhibition

Degradate:

AE F096918

(>99%)

EC50

(72 hours)

14

[6.3-31] 47333422

NOAEC (Supplemental)

(72 hours) 30

Raphidocelis 

subcapitata

(Green algae)

% Inhibition

Formulation:

FPE + HOE 

107892

(12.5%)

EC50

(120 hours) 0.1 47333427

NOAEC (Supplemental)

(120 hours) 0.063

Navicula 

pelliculosa

(Freshwater 

Diatom)

% Inhibition FPE

(97.5%)

EC50

(96 hours) >0.48 48566201

NOAEC (Acceptable)

(96 hours) 0.48

Navicula 

pelliculosa

(Freshwater 

Diatom)

% Inhibition FPE

(88.1%)

EC50

(96 hours) 2.5 44768105

NOAEC (Supplemental)

(96 hours) 1.54

Skeletonema 

costatum 

(Marine diatom)

% Inhibition FPE

(88.1%)

EC50

(96 hours) >1.8 44768104

NOAEC (Supplemental)

(96 hours) <0.21

Anabaena flos-

% Inhibition FPE

(88.1%)

EC50

(96 hours) >0.73 44768103
-Page 41 of 116-

Species

(Common Name)

Measure of 

Effect

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

mg a.i./L

MRID

(Study 

Classification)

aquae

(Cyanobacteria)

NOAEC

(96 hours) <0.73

(Supplemental)

Anabaena flosaquae

(Cyanobacteria)

% Inhibition FPE

(97.5%)

EC50

(96 hours) >0.61 48566202

NOAEC (Acceptable)

(96 hours) 0.61

*Represents the most sensitive toxicity endpoint to be used in RQ calculations

1 Classification is based on preliminary study review which will be finalized before completion of the final risk 

assessment.

3.3.1.4. Degradate Toxicity Predictions using QSAR

Toxicity data summarized in Sections 3.3.1.1 to 3.3.1.3 indicate that transformation products of 

FPE, particularly fenoxaprop-p, may be less toxic to a range of aquatic organisms as compared to 

the parent compound. In an attempt to further compare toxicity of FPE and its transformation 

products, acute and chronic data were generated using quantitative structure-activity relationships 

(QSAR) derived in the program ECOSAR (version 1.11). ECOSAR is only used to explore 

relative toxicity among chemicals and is not used to derive endpoint values for estimating risk. 

Details of this analysis can be found in Appendix H. None of the transformation products were 

placed in the same specific chemical class as the parent (i.e., esters). Therefore, the results of this 

analysis are only marginally useful for risk assessment. However, based on the baseline toxicity 

category (i.e., neutral organics), all transformation products appear to be less toxic than the parent 

by at least a multiple of three. Since, this comparison is not based on a specific class or mode of 

action type, the evidence for lower toxicity of transformation products as compared to FPE is 

considered weak based on QSAR. However, empirical toxicity data for aquatic organisms 

indicates that degradates are less toxic than the parent.

3.3.2. Terrestrial Effects Characterization

3.3.2.1. Toxicity to Animals

A summary of the toxicity data for birds, mammals, and honeybees (Apis mellifera) is provided in 

Table 3.12.

On an acute oral exposure basis, FPE is slightly toxic to partridge (Purdix purdix; MRID 

47333404) and practically non-toxic to mallard ducks (Anas platyrhynchos; MRID 47333402), 

bobwhite quail (Colinus virginianus; MRID 47333403), and Japanese quail (Coturnix coturnix 

japonica; MRID 47333401). Clinical signs of toxicity observed in these studies included reduced 

spontaneous activity, ruffled feathers, standing on hocks, diarrhea, rapid, shallow breathing, closed 

palpebral fissures, reduced sound production, lateral position, uncoordinated or staggering gait, 

and/or gasping but in many cases, these effects subsided before the end of the test observation 

period. On a subacute dietary exposure basis, FPE is practically non-toxic to all species tested

(MRIDs 47333405, 47333406, 47333407).
-Page 42 of 116-

In a 21-week reproductive toxicity study (MRID 47333408), Northern bobwhite quail (Colinus 

virginianus) were exposed to FPE mean-measured concentrations of 192, 404, and 760 mg a.i./kg 

diet, respectively. Overall food consumption (Weeks 1-21) averaged 35.9, 35.4, 34.6, and 33.9 

g/day for the control, 192, 404, and 760 mg a.i./kg diet levels, respectively, and there was a slight 

but statistically significant (p<0.05) decrease in food consumption at the 760 mg a.i./kg-diet level 

as compared to the compared to the control. In addition, at the 760 mg a.i./kg-diet level, there was 

a statistically significant decrease in the number of eggs laid/hen (10%, relative to control), and 

correspondingly, statistically significant (p<0.05) decreases in the number of eggs set (11%, 

relative to control), viable embryos (12%, relative to control), live embryos (11%, relative to 

control), and hatchling survival (14%, relative to control). No other statistically significant 

differences were observed on any adult or offspring parameters during the study. The subsequent 

NOAEC is considered to be 404 mg a.i./kg diet, equivalent to an intake of approximately 30.8 mg 

a.i./kg-bw/day.

FPE is classified as practically non-toxic to mammals on an acute oral exposure basis. There are 

no relevant multi-generation toxicity studies in mammals for FPE. Chronic exposures to 

fenoxaprop-ethyl during a two-generation reproduction study in rats (MRID 00159920) did not 

show effects to survival, growth, or reproduction at any of the concentrations tested, resulting in a 

NOAEL of 9 mg/kg/day (180 mg/kg-diet), i.e., the highest dietary concentration tested. In a two 

year feeding study in dogs (MRID 00151566), reduced body weight (10-13%) and reduced body 

weight gain (46-51%) relative to controls at test termination resulted in NOAEL and LOAEL 

values of 0.375 and 1.875 mg/kg/day, respectively.

In acute oral and acute contact toxicity tests, young adult honey bees were exposed to FPE

technical (MRID 47333402). No mortalities or sublethal effects were observed in either study. 

The LD50 was >192 μg a.i./bee, the highest exposure level tested; therefore, FPE technical is 

classified as practically non-toxic to young adult honey bees on an acute contact exposure basis.

A formulation containing both FPE and mefenpyr-diethyl active ingredients resulted in higher 

toxicity on an acute contact exposure basis when corrected for the percentage of FPE in the 

formulation (LD50 was 58 μg FPE/bee), but is still considered to be practically non-toxic to 

honeybees based on the current classification system where an LD50 >11 μg a.i./bee is classified 

as practically non-toxic.

Table 3.12. Summary of Toxicity Data for Terrestrial Animals Exposed to FPE.

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Birds

Anas 

platyrhynchos

(Mallard duck)

Acute Oral

(Mortality)

FPE

(95.6%)

LD50

(14 days)

>2000 mg 

a.i./kg-bw

(practically nontoxic)

47333402

(Acceptable)

Anas 

platyrhynchos

(Mallard duck)

Subacute 

Dietary

(Mortality)

FPE

(95.6%)

LC50

(8 days)

>4630 mg 

a.i./kg-diet

(practically nontoxic)

47333407

(Acceptable)
-Page 43 of 116-

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Anas 

platyrhynchos

(Mallard duck)

Subacute 

Dietary

(Mortality)

Fenoxapropethyl

(96.6%)

LC50

>5620 mg 

a.i./kg-diet

(practically nontoxic)

00130333

(Acceptable)

Anas 

platyrhynchos

(Mallard duck)

Reproduction

(Hatching)

Fenoxapropethyl

(95.5%)

NOAEC

LOAEC

30 mg a.i./kgdiet 

180 mg a.i./kgdiet

00155304

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Acute Oral

(Mortality)

FPE

(95.6%)

LD50

(14 days)

>2000 mg 

a.i./kg-bw

(practically nontoxic)

47333403

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Acute Oral

(Mortality)

Fenoxapropethyl

(96.6%)

LD50

>2510 mg 

a.i./kg-bw

(practically nontoxic)

00130330

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Subacute 

Dietary

(Mortality)

FPE

(95.6%)

LC50

(11 days)

>4220 mg 

a.i./kg-diet

(practically nontoxic)

47333406

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Subacute 

Dietary

(Mortality)

Fenoxapropethyl

(96.6%)

LC50

>5620 mg 

a.i./kg-diet

(practically nontoxic)

00130334

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Reproduction

(parental food 

consumption, 

eggs laid, eggs 

set, viable 

embryos, live 

embryos, and 

hatchling

survival)

FPE

(95.1%)

NOAEC

LOAEC 

(21 weeks)

404 mg a.i./kgdiet*

760 mg a.i./kgdiet

47333408

(Acceptable)

Colinus 

virginianus

(Bobwhite quail)

Reproduction

(Hatching)

Fenoxapropethyl

(95.5%)

NOAEC

LOAEC

180 mg a.i./kgdiet 

>180 mg a.i./kgdiet

00155305

(Acceptable)

Coturnix coturnix 

japonica

(Japanese quail)

Acute Oral

(Mortality)

FPE

(95.9%)

LD50

(14 days)

>2000 mg 

a.i./kg-bw

(practically nontoxic)

47333401

(Acceptable)

Coturnix coturnix 

japonica

(Japanese quail)

Acute Oral

(Mortality)

Fenoxapropethyl

(TGAI)

LD50

>5000 mg 

a.i./kg-bw

(practically nontoxic)

00130331/

00130332

(Supplemental)

Coturnix coturnix 

japonica

(Japanese quail)

Subacute 

Dietary

(Mortality)

FPE

(95.6%)

LC50

(8 days)

>5106 mg 

a.i./kg-diet

(practically nontoxic)

47333405

(Acceptable)
-Page 44 of 116-

Species

(Common Name)

Study Type

(Measure of 

Effect)

Test Substance 

(% a.i.)

Endpoint

(Test Duration)

Toxicity Value 

[95% CI]

(Acute Toxicity 

Category)

MRID

(Study 

Classification)

Purdix purdix

(Partridge)

Acute Oral

(Mortality)

FPE

(95.9%)

LD50

(14 days)

2000 mg a.i./kgbw*1

(slightly toxic)

47333404

(Acceptable)

Mammals2

Rattus norvegicus

(laboratory rat)

Acute Oral

(Mortality)

FPE 

(95%) LD50

3040 mg/kg-bw 

(males)

2090 mg/kg-bw*

(females)

(practically nontoxic)

42009612

42009613

Rattus norvegicus

(laboratory rat)

Acute Oral

(Mortality)

Fenoxapropethyl

(Technical)

LD50

2357 mg/kg-bw 

(males)

2500 mg/kg-bw 

(females)

(practically nontoxic)

00130010/

00130011

Rattus norvegicus

(laboratory rat) Reproduction

Fenoxapropethyl

(97.2%)

NOAEL

LOAEL

180 mg/kg-diet*

(9 mg/kg/day)

>180 mg/kg-diet

(>9 mg/kg/day)

00159920

Honeybees

Apis mellifera

(Honeybees)

Acute Oral

(Mortality)

FPE

(96.2%)

LC50

(48 hours)

>191.4 μg 

a.i./bee

47333411

(Acceptable)

Apis mellifera

(Honeybees)

Acute Contact

(Mortality)

FPE

(96.2%)

LD50

(48 hours)

>192.4 μg 

a.i./bee*

(practically nontoxic)

47333411

(Acceptable)

Apis mellifera

(Honeybees)

Acute Contact

(Mortality)

Fenoxapropethyl

(TGAI)

LD50

(48 hours)

>100 μg a.i./bee

(practically nontoxic)

00130641

(Acceptable)

Apis mellifera

(Honeybees)

Acute Contact

(Mortality)

Formulation:

Hoe 046360 24 

EC15 A203

(12.5% FPE;

3.37% 

mefenpyrdiethyl)

LD50

(48 hours)

58 μg a.i./bee

(practically nontoxic)

47333430

(Supplemental)

* Most sensitive endpoint; will be used in RQ calculations

1 LD50 is approximately equivalent to the highest dose tested

2 Mammalian toxicity endpoints for FPE/fenoxaprop-ethyl provided and reviewed by EPA/OCSPP/OPP Health 

Effects Division

3.3.2.4. Toxicity to Terrestrial Plants

Terrestrial plant toxicity studies are required for pesticides that have terrestrial use patterns or may 

move off of the application site via drift or volatilization. A summary of the toxicity data for 

terrestrial plants is provided in Table 3.13. NOAEL and IC25 (concentration that causes an effect 

in 25% of the population for the monitored endpoint) values are established for markers of seedling 

emergence and vegetative vigor.
-Page 45 of 116-

Seedling emergence (MRIDs 41276904, 47333423) and vegetative vigor (MRIDs 41276907, 

47333424) tests with formulations containing FPE have been submitted (Table 3.13). Studies 

submitted after the Preliminary Problem Formulation for Registration Review for FPE are 

summarized below.

In a seedling emergence study (MRID 47333423), the effects of Puma® 120 Super (formulation 

containing FPE, 120 g/L, and the mefenpyr-diethyl, 33 g/L) on monocots (Canada bluejoint marsh 

reed, Calamagrostis canadensis; corn, Zea mays; Northern wheatgrass, gropyron dasystachyum; 

onion, Allium cepa) and dicots (alfalfa, Medicago sativa; carrot, Daucus carata; cucumber, 

Cucumis sativa; lettuce, Lactuca sativa; soybean, Glycine max; and tomato, Lycopersicon 

esculentum) were studied at nominal concentrations of 0.001, 0.005, 0.010, 0.020, 0.040, and 0.081 

lbs a.i./A for corn, while all other species were tested at the single application rate (limit test) of 

0.081 lbs a.i./A. Shoot dry weight/plant was significantly inhibited in cucumber and tomato. Shoot 

length was significantly inhibited in bluejoint marsh reed. The percent inhibition in seedling 

emergence in the treated species as compared to the control ranged from -16.7% (bluejoint) to 

7.0% (onion). The most sensitive monocot in the single application rate test, based on a 20.8% 

inhibition in shoot length, was bluejoint marsh reed. The most sensitive dicot in the single 

application rate test, based on a 16.9% inhibition in shoot dry weight/plant, was tomato; since the 

exposure resulted in <25% inhibition, higher tier testing of multiple exposure levels was not 

required. In the multiple application rate test with corn, root length was the most sensitive endpoint 

with NOAEC and EC25/IC25 values of 0.005 and 0.011 lbs a.i./A, respectively. Shoot dry 

weight/plant and shoot length were significantly (p<0.05) inhibited in corn. Corn also exhibited 

inhibitions in root length and root dry weight.

In a vegetative vigor study (MRID 47333424), the effects of Puma® 120 Super (formulation 

containing fenoxaprop-p-ethyl, 120 g/L, and the mefenpyr-diethyl, 33 g/L) on monocots (Canada 

bluejoint marsh reed, Calamagrostis canadensis; corn, Zea mays; Northern wheatgrass, gropyron 

dasystachyum; onion, Allium cepa) and dicots (alfalfa, Medicago sativa; carrot, Daucus carata; 

cucumber, Cucumis sativa; lettuce, Lactuca sativa; soybean, Glycine max; and tomato, 

Lycopersicon esculentum) were studied at varying nominal application rates. Corn seedlings were 

treated with nominal application rates of 0.0000095, 0.000039, 0.00016, 0.00063, 0.0025, 0.010 

and 0.020 lbs a.i./A. Bluejoint marsh reed and carrot seedlings were treated with nominal 

application rates of 0.0013, 0.0025, 0.0051, 0.010, 0.020, 0.041 and 0.081 lbs a.i./A. Lettuce 

seedlings were treated with nominal application rates of 0.0051, 0.010, 0.020, 0.041 and 0.081 lbs

a.i./A. Onion, Northern wheatgrass, soybean, cucumber, tomato and alfalfa were treated at a single 

application rate of 0.081 lbs a.i./A. The dry weight per plant and plant height of Northern 

wheatgrass, onion, alfalfa, cucumber, lettuce, soybean and tomato were not affected, i.e., NOAEC 

equaled the highest treatment ratio. Shoot and root dry weights per plant were significantly 

(p<0.05) affected (inhibitions >25%) for carrot, corn and bluejoint marsh reed. Shoot length and 

root length were significantly (p<0.05) inhibited (inhibitions >25%) for corn and bluejoint only. 

Corn was the only species to exhibit reductions in percent survival. No monocot or dicot species 

exhibited significant sensitivity in the single application rate test. The most sensitive monocot in 

the multiple application rate test was corn, based on root dry weight per plant, with NOAEC and 

EC25 values of 0.0025 and 0.0073 lbs a.i./A, respectively. The most sensitive dicot in the Tier II 

test was carrot, based on reductions in root dry weight per plant, with NOAEC and EC25 values of 
-Page 46 of 116-

0.041 and 0.058 lbs a.i./A, respectively. With the exception of corn, no species exhibited 

significant dose-dependent phytotoxic effects. Observed effects included chlororsis, necrosis, leaf 

curl and wilting. 

Table 3.13. Summary of Tier I and Tier II Toxicity of FPE to Non-target Terrestrial Plants.

Crop Test 

Substance

Type of 

Study 

Species

IC25

(lbs a.i./A)

NOAEC

or IC05

(lbs a.i./A)

Endpoint Affected MRID

Seedling Emergence

Monocots

(Tier 1)

Formulation: 

HOE 

046360 

(FPE Disomer

7.2%)

Corn, Oat, 

Onion, 

Ryegrass

<0.1 NA

Root length (all 

species); plant 

height (corn, 

ryegrass); plant dry 

weight (ryegrass, 

onion) 41276904

(Acceptable)

Dicots

(Tier 1)

Cabbage, 

Lettuce, 

Carrot, 

Tomato, 

Cucumber, 

Soybean

>0.1 NA NA

Monocots

(Tier 2)

Corn 0.002* <0.00061 Root length

41276905

(Acceptable)

Oat 0.0096 <0.0006 Root length

Onion NA >0.0960 NA

Ryegrass 0.0578 <0.0240 Plant height

Monocots

(Tier 1)

Puma® 120 

Super

(120 g/L 

FPE;

33 g/L 

Mefenpyrdiethyl)

Northern 

Wheatgrass, 

Onion

>0.081 0.081 NA

47333423

(Acceptable)

Canada 

bluejoint 

marsh reed

>0.081 <0.081 Shoot length

Dicots

(Tier 1)

Alfalfa, 

Carrot, 

Lettuce, 

Soybean,

>0.0811 0.081 NA

Cucumber, 

Tomato >0.081 <0.0811 Shoot dry weight

Monocots

(Tier 2) Corn 0.011 0.005 Root length

Vegetative Vigor

Monocots

(Tier 1)

Formulation: 

HOE 

046360 

(FPE Disomer

7.2%)

Corn, Oat, 

Onion, 

Ryegrass

< 0.1 NA Plant Height, Plant 

dry weight

41276904

(Acceptable) Dicots

(Tier 1)

Cabbage, 

Lettuce, 

Carrot, 

Tomato, 

Cucumber, 

Soybean

> 0.1 NA NA

Monocots

(Tier 2)

Corn 0.0025* < 0.00061 Plant height 41276907

(Acceptable) Oat 0.0779 NA Plant dry weight

Ryegrass 0.0817 < 0.0480 Plant height

Monocots

(Tier 1)

Puma® 120 

Super

Northern 

Wheatgrass, > 0.081 0.081 NA 47333424(Acceptable)
-Page 47 of 116-

(120 g/L 

FPE;

33 g/L 

Mefenpyrdiethyl)

Onion

Dicots

(Tier 1)

Alfalfa, 

Cucumber, 

Tomato, 

Soybean

> 0.081 0.081 NA

Monocots

(Tier 2)

Canada 

bluejoint 

marsh reed

0.024 0.010

Shoot dry 

weight/plant; root 

length

Corn 0.0073 0.0025 Root dry 

weight/plant

Dicots 

(Tier 2)

Lettuce > 0.081 0.081 NA

Carrot 0.058* 0.041*

Root dry 

weight/plant

* Most sensitive endpoint used for risk estimation (i.e., RQ calculations)

1 Non-definitive endpoint used to characterize risk to terrestrial plants in risk discussion (i.e., not used for RQ 

calculations)

3.3.3. Review of Incident Data

The Ecological Incident Information System (EIIS), which is maintained by the Agency’s Office 

of Pesticide Programs, was searched to determine if ecological incidents have been reported for

FPE. Based on a search of EIIS conducted in November 2013, the Agency has received 113 reports 

of adverse field effects to non-target plants that have been linked to the use of FPE. All of these 

incidents involved damage to a grain crop (barley, corn, lentil, rice, or wheat). The Agency 

considered the cause to be uncertain in 75 cases because more than one herbicide was applied to 

the crop. In the remaining 38 cases, the Agency considers FPE to be the probable cause. Most of 

the incidents were reports of crop damage that occurred following application of the herbicide 

directly to the crop, although four incidents occurred from carryover effects of applications made 

to another crop in a previous growing season. None of the incidents involved damage to crops or 

other plants outside the treatment site. 

The Agency has received one report linking FPE to adverse field effects to wild animals. In 1998, 

approximately 200 fish died in a pond in White County, Illinois following application of FPE, 

along with two other herbicides (fluazifop-p-butyl and fomesafen sodium), on a nearby soybean 

field. Because FPE is highly toxic to fish on an acute exposure basis and was applied in close 

proximity to the pond, the Agency believes that exposure to this herbicide was a probable cause 

or contributing factor to the fish mortality.

The Agency has received two reports of adverse field effects to non-target animals or plants that 

have been attributed to the use of fenoxaprop-ethyl. In 2009, approximately 320 bee hives resulted 

in mortalities in Box Elder, UT following the application of fenoxaprop-ethyl (application method 

was not specified). In 2011, approximately 400 acres of wheat were damaged in Sargent, ND after 

being treated with fenoxaprop-ethyl. The Agency also has no incident report from pesticide 

registrants concerning fenoxaprop-ethyl contamination of ground or surface water.

The American Bird Conservancy Avian Incident Monitoring System was searched in November 

2013 and returned no records of incidents associated with FPE or fenoxaprop-ethyl2.

 

2 http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/index.cfm
-Page 48 of 116-

Based on a search of the U.S. EPA Office of Pesticide Programs Incident Data System (IDS), 

which compiles aggregate incidents, there were a total of 63 incidents involving fenoxaprop-pethyl between 1998 and 2013, of which 63 were associated with minor plant damage, two were 

associated with minor impacts to wildlife, and one incident was listed as “other.” There was a 

single incident in IDS for fenoxaprop-ethyl associate with minor plant damage.

A lack of reported incidents does not necessarily mean that such incidents have not occurred. In 

addition, incident reports for non-target plants and animals typically provide information on acute 

mortality events only. Reports for other adverse effects, such as reduced growth or impaired 

reproduction, are rarely received.

4. Risk Characterization

4.1. Risk Estimation

This screening-level assessment of the labeled uses of FPE relies on the deterministic RQ method 

to provide a metric of potential risks. The RQ provides a comparison of exposure estimates to 

toxicity endpoints (i.e., the estimated exposure concentrations are divided by acute and chronic 

toxicity values, respectively). The resulting unitless RQ values are compared to the Agency’s 

LOCs. The LOCs, when exceeded, are used by the Agency to indicate when the use of a pesticide, 

as directed by the label, has the potential to cause adverse effects to nontarget organisms. For 

endangered species, LOC exceedances require an additional in-depth evaluation of the potential 

co-occurrence of listed species and areas in which new use crops are grown to characterize risks. 

In all cases, RQs that exceed the risk to non-listed species LOC also exceed the listed species LOC.

 

4.1.1. Aquatic Organisms

Tables 4.1 to 4.4 present RQ values calculated for aquatic organisms exposed to FPE residues in 

surface water based on toxicity data for the TGAI, while Table 4.5 presents RQ values for aquatic 

organisms exposed to spray drift only based on toxicity data for FPE formulations. Individual 

effect probabilities and their significance in risk assessment are described in Section 2.6.3.
-Page 49 of 116-

Table 4.1. Acute and Chronic RQs for Direct Effects to Freshwater Vertebrates from FPE TGAI.

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Freshwater Vertebrates

LC50 = 460 μg a.i./L (slope = 

NA) 1-in-10-year

60-day average 

(μg/L)

Freshwater 

Vertebrates

NOAEC =

44 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Barley / Wheat

CAWheatRLF_V2

0.083, 0.105

0.74 <0.01 >9x1018 0.02 <0.01

NDwheatSTD 0.82 <0.01 >9x1018 0.02 <0.01

ORwheatOP3 0.74 <0.01 >9x1018 0.01 <0.01

TXwheatOP3 0.81 <0.01 >9x1018 0.01 <0.01

Conservation 

Reserve

CAalfalfa_WirrigOP

0.1, 0.028, 

0.06

0.70 <0.01 >9x1018 0.02 <0.01

ILalfalfaNMC 0.70 <0.01 >9x1018 0.04 <0.01

MNalfalfaOP 0.70 <0.01 >9x1018 0.04 <0.01

NCalfalfaOP 0.80 <0.01 >9x1018 0.03 <0.01

PAalfalfaOP 0.86 <0.01 >9x1018 0.04 <0.01

TXalfalfaOP 0.70 <0.01 >9x1018 0.02 <0.01

Cotton

CAcotton_WirrigSTD

0.105

0.74 <0.01 >9x1018 0.01 <0.01

MScottonSTD 0.78 <0.01 >9x1018 0.01 <0.01

NCcottonSTD 0.75 <0.01 >9x1018 0.01 <0.01

STXcottonNMC 0.74 <0.01 >9x1018 0.01 <0.01

TXcottonOP 0.74 <0.01 >9x1018 0.01 <0.01

Ornamental

CAnurserySTD

0.173, 0.173, 

0.173, 0.012

1.21 <0.01 >9x1018 0.08 <0.01

FLnurserySTD 1.78 <0.01 >9x1018 0.07 <0.01

MInurserySTD_V2 1.47 <0.01 >9x1018 0.17 <0.01

NJnurserySTD 1.51 <0.01 >9x1018 0.14 <0.01

NurseryBSS_V2 1.73 <0.01 >9x1018 0.09 <0.01

ORnurserySTD 1.22 <0.01 >9x1018 0.12 <0.01

TNnurserySTD 1.92 <0.01 >9x1018 0.10 <0.01

Rice Tier 1 Rice Model4 0.071, 0.071 83.35 0.18 2,000 0.32 0.01
-Page 50 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Freshwater Vertebrates

LC50 = 460 μg a.i./L (slope = 

NA) 1-in-10-year

60-day average 

(μg/L)

Freshwater 

Vertebrates

NOAEC =

44 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Right-of-Way

CArightofwayRLF_V2 0.173, 0.173, 

0.173, 0.012

1.26 <0.01 >9x1018 0.10 <0.01

RightOfWayBSS 1.96 <0.01 >9x1018 0.09 <0.01

Soybeans MSsoybeanSTD 0.1, 0.028, 

0.06 0.78 <0.01 >9x1018 0.01 <0.01

Turf

CATurfRLF

0.173, 0.173, 

0.173, 0.012

0.58 <0.01 >9x1018 0.02 <0.01

FLturfSTD 0.58 <0.01 >9x1018 0.01 <0.01

PAturfSTD 0.60 <0.01 >9x1018 0.03 <0.01

Grass grown for 

seed

CATurfRLF

0.083

1.22 <0.01 >9x1018 0.12 <0.01

FLturfSTD 1.88 <0.01 >9x1018 0.07 <0.01

PAturfSTD 1.28 <0.01 >9x1018 0.12 <0.01

Abbreviations: App. Application.

A bold cell indicates that the RQ meets or exceeds the LOC for acute (LOC = 0.05) risk or chronic (LOC=1) to listed species.

1 Values for all scenarios except rice represent 1-in-10 year return frequency daily concentrations. Value for rice scenario represents an actual maximum 

concentration, since the Tier 1 rice model does not address inter-annual variability.

2 Probability of individual mortality based on actual screening level RQ value for TTR. A default concentration-response slope value of 4.5 is used to generate the 

probability value because slope values were not calculable from the available test data (USEPA 2004).

3 Winter wheat scenarios, so harvest is in summer. First app date was done at 0.105 lb/A, with second app date at 0.083 lb/A.

4 The maximum rate per season is 0.142 lbs a.i./A, while the maximum annual rate is 0.188 lbs a.i./A. As the paddy water is discharged prior to the third 

treatment, the third treatment is not included in the estimation of the EECs.

Table 4.2. Acute and Chronic RQs for Direct Effects to Freshwater Invertebrates from FPE TGAI.

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Freshwater Invertebrates

EC50 = 3180 μg a.i./L (slope = 

1.4)

1-in-10-year

21-day 

average 

(μg/L)

Freshwater 

Invertebrates

NOAEC =

230 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Barley / Wheat CAWheatRLF_V2 0.083, 0.105 0.74 <0.01 >400 0.06 0.01 (<0.01)
-Page 51 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Freshwater Invertebrates

EC50 = 3180 μg a.i./L (slope = 

1.4)

1-in-10-year

21-day 

average 

(μg/L)

Freshwater 

Invertebrates

NOAEC =

230 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

NDwheatSTD 0.82 <0.01 >400 0.04 <0.01

ORwheatOP3 0.74 <0.01 >400 0.04 <0.01

TXwheatOP3 0.81 <0.01 >400 0.04 <0.01

Conservation 

Reserve

CAalfalfa_WirrigOP

0.1, 0.028, 

0.06

0.70 <0.01 >400 0.07 <0.01

ILalfalfaNMC 0.70 <0.01 >400 0.11 <0.01

MNalfalfaOP 0.70 <0.01 >400 0.12 <0.01

NCalfalfaOP 0.80 <0.01 >400 0.09 <0.01

PAalfalfaOP 0.86 <0.01 >400 0.11 <0.01

TXalfalfaOP 0.70 <0.01 >400 0.07 <0.01

Cotton

CAcotton_WirrigSTD

0.105

0.74 <0.01 >400 0.04 <0.01

MScottonSTD 0.78 <0.01 >400 0.04 <0.01

NCcottonSTD 0.75 <0.01 >400 0.04 <0.01

STXcottonNMC 0.74 <0.01 >400 0.04 <0.01

TXcottonOP 0.74 <0.01 >400 0.04 <0.01

Ornamental

CAnurserySTD

0.173, 0.173, 

0.173, 0.012

1.21 <0.01 >400 0.15 <0.01

FLnurserySTD 1.78 <0.01 >400 0.15 <0.01

MInurserySTD_V2 1.47 <0.01 >400 0.33 <0.01

NJnurserySTD 1.51 <0.01 >400 0.27 <0.01

NurseryBSS_V2 1.73 <0.01 >400 0.16 <0.01

ORnurserySTD 1.22 <0.01 >400 0.22 <0.01

TNnurserySTD 1.92 <0.01 >400 0.19 <0.01

Rice Tier 1 Rice Model4 0.071, 0.071 83.35 0.03 6.1 0.91 <0.01

Right-of-Way

CArightofwayRLF_V2 0.173, 0.173, 

0.173, 0.012

1.26 <0.01 >400 0.19 <0.01

RightOfWayBSS 1.96 <0.01 >400 0.16 <0.01
-Page 52 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Freshwater Invertebrates

EC50 = 3180 μg a.i./L (slope = 

1.4)

1-in-10-year

21-day 

average 

(μg/L)

Freshwater 

Invertebrates

NOAEC =

230 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Soybeans MSsoybeanSTD 0.1, 0.028, 

0.06 0.78 <0.01 >400 0.04 <0.01

Turf

CATurfRLF

0.173, 0.173, 

0.173, 0.012

0.58 <0.01 >400 0.06 <0.01

FLturfSTD 0.58 <0.01 >400 0.04 <0.01

PAturfSTD 0.60 <0.01 >400 0.07 <0.01

Grass grown for 

seed

CATurfRLF

0.083

1.22 <0.01 >400 0.23 <0.01

FLturfSTD 1.88 <0.01 >400 0.15 <0.01

PAturfSTD 1.28 <0.01 >400 0.24 <0.01

Abbreviations: App. Application.

1 Values for all scenarios except rice represent 1-in-10 year return frequency daily average concentrations. Value for rice scenario represents an actual peak 

concentration, since the Tier 1 rice model does not account for inter-annual variability.

2 Probability of individual mortality based on actual screening level RQ value. Based on an empirical slope of 1.4.

3 Winter wheat scenarios, so harvest is in summer. First app date was done at 0.105 lb/A, with second app date at 0.083 lb/A.

4 The maximum rate per season is 0.142 lbs a.i./A, while the maximum annual rate is 0.188 lbs a.i./A. As the paddy water is discharged prior to the third 

treatment, the third treatment is not included in the estimation of the EECs.

Table 4.3. Acute and Chronic RQs for Direct Effects to Estuarine/Marine Invertebrates from FPE TGAI.

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Est/Mar

Invertebrates

LC50 = 110 μg a.i./L (slope = 5) 1-in-10-year

21-day average 

(μg/L)

Est/Mar 

Invertebrates

NOAEC =

11 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Barley / Wheat

CAWheatRLF_V2

0.083, 0.105

0.74 0.01 1x1023 0.06 0.01

NDwheatSTD 0.82 0.01 1x1023 0.04 <0.01

ORwheatOP3 0.74 0.01 1x1023 0.04 <0.01

TXwheatOP3 0.81 0.01 1x1023 0.04 <0.01
-Page 53 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Est/Mar

Invertebrates

LC50 = 110 μg a.i./L (slope = 5) 1-in-10-year

21-day average 

(μg/L)

Est/Mar 

Invertebrates

NOAEC =

11 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

Conservation 

Reserve

CAalfalfa_WirrigOP

0.1, 0.028, 

0.06

0.70 0.01 1x1023 0.07 0.01

ILalfalfaNMC 0.70 0.01 1x1023 0.11 0.01

MNalfalfaOP 0.70 0.01 1x1023 0.12 0.01

NCalfalfaOP 0.80 0.01 1x1023 0.09 0.01

PAalfalfaOP 0.86 0.01 1x1023 0.11 0.01

TXalfalfaOP 0.70 0.01 1x1023 0.07 0.01

Cotton

CAcotton_WirrigSTD

0.105

0.74 0.01 1x1023 0.04 <0.01

MScottonSTD 0.78 0.01 1x1023 0.04 <0.01

NCcottonSTD 0.75 0.01 1x1023 0.04 <0.01

STXcottonNMC 0.74 0.01 1x1023 0.04 <0.01

TXcottonOP 0.74 0.01 1x1023 0.04 <0.01

Ornamental

CAnurserySTD

0.173, 0.173, 

0.173, 0.012

1.21 0.01 1x1023 0.15 0.01

FLnurserySTD 1.78 0.02 1x1017 0.15 0.01

MInurserySTD_V2 1.47 0.01 1x1023 0.33 0.03

NJnurserySTD 1.51 0.01 1x1023 0.27 0.02

NurseryBSS_V2 1.73 0.02 1x1017 0.16 0.01

ORnurserySTD 1.22 0.01 1x1023 0.22 0.02

TNnurserySTD 1.92 0.02 1x1017 0.19 0.02

Rice Tier 1 Rice Model4 0.071, 0.071 83.35 0.76 3.6 0.91 0.08

Right-of-Way

CArightofwayRLF_V2 0.173, 0.173, 

0.173, 0.012

1.26 0.01 1x1023 0.19 0.02

RightOfWayBSS 1.96 0.02 1x1017 0.16 0.01

Soybeans MSsoybeanSTD 0.1, 0.028, 

0.06 0.78 0.01 1x1023 0.04 <0.01

Turf

CATurfRLF 0.173, 0.173, 

0.173, 0.012

0.58 0.01 1x1023 0.06 0.01

FLturfSTD 0.58 0.01 1x1023 0.04 <0.01
-Page 54 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10-

year

1-day 

average1

(μg/L)

Est/Mar

Invertebrates

LC50 = 110 μg a.i./L (slope = 5) 1-in-10-year

21-day average 

(μg/L)

Est/Mar 

Invertebrates

NOAEC =

11 μg a.i./L

RQs

Probability of Acute 

Effect2

(1 in ...)

RQs

PAturfSTD 0.60 0.01 1x1023 0.07 0.01

Grass grown for 

seed

CATurfRLF

0.083

1.22 0.01 1x1023 0.23 0.02

FLturfSTD 1.88 0.02 1x1017 0.15 0.01

PAturfSTD 1.28 0.01 1x1023 0.24 0.02

Abbreviations: App. Application. Est/Mar – Estuarine/Marine

A bold cell indicates that the RQ meets or exceeds the LOC for acute (LOC = 0.05) risk or chronic (LOC=1) to listed species.

1 Values for all scenarios except rice represent 1-in-10 year return frequency daily average concentrations. Value for rice scenario represents an actual peak 

concentration, since the Tier 1 rice model does not account for inter-annual variability.

2 Probability of individual mortality based on actual screening level RQ value. Based on an empirical slope of 5.

3 Winter wheat scenarios, so harvest is in summer. First app date was done at 0.105 lb/A, with second app date at 0.083 lb/A.

4 The maximum rate per season is 0.142 lbs a.i./A, while the maximum annual rate is 0.188 lbs a.i./A. As the paddy water is discharged prior to the third 

treatment, the third treatment is not included in the estimation of the EECs.

Table 4.4. RQ Values for Direct Effects to Aquatic Vascular and Nonvascular Plants from FPE TGAI.

Crop Scenario App Rate

(lbs/A)

1-in-10 year 

1-day 

average1

(μg a.i./L)

Aquatic 

Vascular 

Plants

NOAEC = 

3,000 μg a.i./L

Aquatic Nonvascular Plants

IC50 = 430 μg a.i./L

NOAEC = 27 μg a.i./L

Listed RQs Listed RQs Non-listed

RQs

Barley / Wheat

CAWheatRLF_V2

0.083, 0.105

0.74 <0.01 0.03 <0.01

NDwheatSTD 0.82 <0.01 0.03 <0.01

ORwheatOP2 0.74 <0.01 0.03 <0.01

TXwheatOP2 0.81 <0.01 0.03 <0.01

Conservation Reserve

CAalfalfa_WirrigOP

0.1, 0.028, 0.06

0.70 <0.01 0.03 <0.01

ILalfalfaNMC 0.70 <0.01 0.03 <0.01

MNalfalfaOP 0.70 <0.01 0.03 <0.01
-Page 55 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10 year 

1-day 

average1

(μg a.i./L)

Aquatic 

Vascular 

Plants

NOAEC = 

3,000 μg a.i./L

Aquatic Nonvascular Plants

IC50 = 430 μg a.i./L

NOAEC = 27 μg a.i./L

Listed RQs Listed RQs Non-listed

RQs

NCalfalfaOP 0.80 <0.01 0.03 <0.01

PAalfalfaOP 0.86 <0.01 0.03 <0.01

TXalfalfaOP 0.70 <0.01 0.03 <0.01

Cotton

CAcotton_WirrigSTD

0.105

0.74 <0.01 0.03 <0.01

MScottonSTD 0.78 <0.01 0.03 <0.01

NCcottonSTD 0.75 <0.01 0.03 <0.01

STXcottonNMC 0.74 <0.01 0.03 <0.01

TXcottonOP 0.74 <0.01 0.03 <0.01

Ornamental

CAnurserySTD

0.173, 0.173, 0.173, 

0.012

1.21 <0.01 0.04 <0.01

FLnurserySTD 1.78 <0.01 0.07 <0.01

MInurserySTD_V2 1.47 <0.01 0.05 <0.01

NJnurserySTD 1.51 <0.01 0.06 <0.01

NurseryBSS_V2 1.73 <0.01 0.06 <0.01

ORnurserySTD 1.22 <0.01 0.05 <0.01

TNnurserySTD 1.92 <0.01 0.07 <0.01

Rice Tier 1 Rice Model3 0.071, 0.071 83.35 0.03 3.09 0.19

Right-of-Way

CArightofwayRLF_V2 0.173, 0.173, 0.173, 

0.012

1.26 <0.01 0.05 <0.01

RightOfWayBSS 1.96 <0.01 0.07 <0.01

Soybeans MSsoybeanSTD 0.1, 0.028, 0.06 0.78 <0.01 0.03 <0.01

Turf

CATurfRLF

0.173, 0.173, 0.173, 

0.012

0.58 <0.01 0.02 <0.01

FLturfSTD 0.58 <0.01 0.02 <0.01

PAturfSTD 0.60 <0.01 0.02 <0.01

Grass grown for seed

CATurfRLF

0.083

1.22 <0.01 0.05 <0.01

FLturfSTD 1.88 <0.01 0.07 <0.01
-Page 56 of 116-

Crop Scenario App Rate

(lbs/A)

1-in-10 year 

1-day 

average1

(μg a.i./L)

Aquatic 

Vascular 

Plants

NOAEC = 

3,000 μg a.i./L

Aquatic Nonvascular Plants

IC50 = 430 μg a.i./L

NOAEC = 27 μg a.i./L

Listed RQs Listed RQs Non-listed

RQs

PAturfSTD 1.28 <0.01 0.05 <0.01

Abbreviations: App. Application

A bold cell indicates that the RQ meets or exceeds the LOC for non-listed or listed plants (LOC = 1).

1 Values for all scenarios except rice represent 1-in-10 year return frequency daily average concentrations. Value for rice scenario represents an actual peak 

concentration, since the Tier 1 rice model does not account for inter-annual variability.

2 Winter wheat scenarios, so harvest is in summer. First app date was done at 0.105 lb/A, with second app date at 0.083 lb/A.

3 The maximum rate per season is 0.142 lbs a.i./A, while the maximum annual rate is 0.188 lbs a.i./A. As the paddy water is discharged prior to the third 

treatment, the third treatment is not included in the estimation of the EECs.

Table 4.5. FPE RQs for Formulations Resulting from Spray Drift Only Exposures

Crop Scenario

Peak (μg/L)

Spray Drift 

Only1

Freshwater 

Vertebrates

LC50 = 280 

μg a.i./L (L. 

macrochirus; 

FPE+HOE 

107892)

Freshwater 

Invertebrates

LC50 = 520 μg

a.i./L (D. 

magna; 

FPE+HOE 

107892)

Aquatic Vascular Plants

IC50 = 1,700 μg a.i./L

NOAEC = 94 μg a.i./L (L. 

gibba; PUMA® 120)

Aquatic 

Vascular 

Plants

IC50 = 100 μg

a.i./L (R. 

subcapitata; 

FPE+HOE 

107892)

Non-listed 

RQs Listed RQs Non-listed RQs

Barley / 

Wheat

CAWheatRLF_V2 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

NDwheatSTD 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

ORwheatOP2 0.82 <0.01 <0.01 <0.01 <0.01 <0.01

TXwheatOP2 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

Conservation 

Reserve

CAalfalfa_WirrigOP 0.7 <0.01 <0.01 <0.01 <0.01 <0.01

ILalfalfaNMC 0.7 <0.01 <0.01 <0.01 <0.01 <0.01

MNalfalfaOP 0.7 <0.01 <0.01 <0.01 <0.01 <0.01

NCalfalfaOP 0.7 <0.01 <0.01 <0.01 <0.01 <0.01
-Page 57 of 116-

Crop Scenario

Peak (μg/L)

Spray Drift 

Only1

Freshwater 

Vertebrates

LC50 = 280 

μg a.i./L (L. 

macrochirus; 

FPE+HOE 

107892)

Freshwater 

Invertebrates

LC50 = 520 μg

a.i./L (D. 

magna; 

FPE+HOE 

107892)

Aquatic Vascular Plants

IC50 = 1,700 μg a.i./L

NOAEC = 94 μg a.i./L (L. 

gibba; PUMA® 120)

Aquatic 

Vascular 

Plants

IC50 = 100 μg

a.i./L (R. 

subcapitata; 

FPE+HOE 

107892)

Non-listed 

RQs Listed RQs Non-listed RQs

PAalfalfaOP 0.7 <0.01 <0.01 <0.01 <0.01 <0.01

TXalfalfaOP 0.7 <0.01 <0.01 <0.01 <0.01 <0.01

Cotton

CAcotton_WirrigSTD 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

MScottonSTD 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

NCcottonSTD 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

STXcottonNMC 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

TXcottonOP 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

Ornamental

CAnurserySTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

FLnurserySTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

MInurserySTD_V2 1.22 <0.01 <0.01 <0.01 <0.01 <0.01

NJnurserySTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

NurseryBSS_V2 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

ORnurserySTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

TNnurserySTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

Rice Tier 1 Rice Model NA NA NA NA NA NA

Right-ofWay

CArightofwayRLF_V2 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

RightOfWayBSS 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

Soybeans MSsoybeanSTD 0.74 <0.01 <0.01 <0.01 <0.01 <0.01

Turf

CATurfRLF 0.58 <0.01 <0.01 <0.01 <0.01 <0.01

FLturfSTD 0.58 <0.01 <0.01 <0.01 <0.01 <0.01

PAturfSTD 0.58 <0.01 <0.01 <0.01 <0.01 <0.01
-Page 58 of 116-

Crop Scenario

Peak (μg/L)

Spray Drift 

Only1

Freshwater 

Vertebrates

LC50 = 280 

μg a.i./L (L. 

macrochirus; 

FPE+HOE 

107892)

Freshwater 

Invertebrates

LC50 = 520 μg

a.i./L (D. 

magna; 

FPE+HOE 

107892)

Aquatic Vascular Plants

IC50 = 1,700 μg a.i./L

NOAEC = 94 μg a.i./L (L. 

gibba; PUMA® 120)

Aquatic 

Vascular 

Plants

IC50 = 100 μg

a.i./L (R. 

subcapitata; 

FPE+HOE 

107892)

Non-listed 

RQs Listed RQs Non-listed RQs

Grass grown 

for seed

CATurfRLF 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

FLturfSTD 1.21 <0.01 <0.01 <0.01 <0.01 <0.01

PAturfSTD 1.22 <0.01 <0.01 <0.01 <0.01 <0.01

1 Surface water EECs from spray drift only were calculated to better characterize potential risk to aquatic organisms from exposure to the end-use product (EP). 

The use of these values is discussed further in the Risk Description (Section 4.2).
-Page 59 of 116-

4.1.1.1. Freshwater Fish, Amphibians, and Invertebrates

Based on acute toxicity data for rainbow trout exposed to TGAI (LC50 = 460 μg a.i./L), RQ values 

for acute risk to freshwater fish exceed the level of concern (LOCs) for listed species (LOC =0.05)

for labeled uses on rice (Table 4.2). Based on chronic toxicity endpoint for fathead minnows 

exposed to TGAI (NOAEC = 44 μg a.i./L), the chronic risk to freshwater fish LOC (LOC =1.0)

was not exceeded for any labeled use (Table 4.2).

Based on acute toxicity data for Daphnia exposed to the fenoxaprop-ethyl (LC50 = 3,180 μg a.i./L), 

RQ values for acute risk to freshwater invertebrates do not exceed LOCs for listed (LOC = 0.05)

or non-listed (LOC = 0.5) species for any labeled use of FPE (Table 4.3). Based on chronic 

toxicity endpoint for Daphnia exposed to TGAI (LC50 =230 μg a.i./L), RQ values for chronic risk 

to freshwater invertebrates do not exceed the LOC (LOC =1.0) for any of the uses evaluated (Table 

4.3). 

Based on acute toxicity data for available FPE formulations tested on bluegill sunfish (LC50 = 280

μg a.i./L) and D. magna (EC50 = 520 μg a.i./L), RQ values for acute risk to freshwater vertebrates 

and invertebrates exposed to spray drift are all below 0.01 and do not exceed the LOCs for listed

(LOC =0.05) or non-listed (LOC =0.5) species for any existing or proposed uses (Table 4.5).

4.1.1.2. Estuarine/Marine Vertebrates and Invertebrates

RQ values for acute risk to estuarine/marine fish are not calculated because only a non-definitive 

acute toxicity endpoint was available for the TGAI (sheepshead minnow LC50 > 1,000 μg a.i./L). 

RQ values for chronic risk to estuarine/marine fish are also not presented because no chronic 

toxicity data were submitted for this group. Further characterization of risk to estuarine/marine 

fish is presented in Section 4.2.

Based on an acute toxicity endpoint for mysid shrimp exposed to TGAI (EC50 =110 μg a.i./L), RQ 

values exceed the acute risk LOC for listed species (LOC =0.05) and non-listed species (LOC 

=0.5) of estuarine/marine invertebrates for the labeled use on rice (Table 4.4). Based on chronic

toxicity data for mysid shrimp exposed to the TGAI (NOAEC = 11 μg a.i./L), RQ values for 

chronic risk to estuarine/marine invertebrates do not exceed the LOC (LOC =1.0) for any of the 

uses evaluated.

4.1.1.3. Aquatic Plants

RQ values for labeled uses of FPE are based upon 96-hour phytotoxicity endpoints for green alga 

(R. subcapitata; IC50 =430 μg a.i./L, NOAEC =27 μg a.i./L) and duckweed (L. gibba; IC50 >3,000

μg a.i./L, NOAEC =3000 μg a.i./L), respectively, exposed to TGAI. The RQs are below the LOC 

(LOC = 1) for risk to listed vascular and non-listed nonvascular species of aquatic plants for labeled 

uses. For rice, the RQ (RQ =3.09) exceeds the LOC for risk to listed nonvascular aquatic plants. 
-Page 60 of 116-

RQ values are not calculated for non-listed species of vascular aquatic plants because the IC50

value is non-definitive (i.e., an IC50 was not established within the range of concentrations tested).

Based on acute toxicity data for available FPE formulations tested on the vascular plant duckweed 

(EC50 =1,700 μg a.i./L; NOAEC =94 μg a.i./L) and the nonvascular green algae (EC50 =100 μg 

a.i./L), RQ values resulting from exposure to spray drift do not exceed the LOCs for risk to listed

and non-listed aquatic vascular plants and non-listed aquatic nonvascular plants (LOC=1) (Table 

4.5). Risk to listed species RQs for FPE formulations were not calculated for green algae since the 

NOAEC resulting from exposure to FPE TGAI is lower than the NOAEC resulting from exposure 

to the tested formulation. 

4.1.2. Terrestrial Organisms

4.1.2.1. Birds and Mammals

Acute dose-based RQ values for birds based on toxicity data for the partridge (LD50 = 2,000 mg 

a.i./kg-bw) range from <0.01 to 0.08 across labeled uses of FPE and do not exceed the acute risk 

to listed and non-listed species LOCs of 0.1 and 0.5, respectively. RQ values are not calculated for

acute risk to birds on a dietary exposure basis because the available acute toxicity endpoints for 

bobwhite quail and mallard duck are non-definitive (bobwhite quail LC50 >4,220 mg a.i./kg-diet;

mallard LC50 >4,630 mg a.i./kg-diet). The potential for risk to birds (and therefore to terrestrialphase amphibians and reptiles) is further discussed in the Risk Description (Section 4.2).

Chronic RQ values for birds based upon a NOAEC of 404 mg a.i./kg-diet for the bobwhite quail 

range from <0.01 to 0.24 across label uses of FPE and therefore do not exceed the chronic risk 

LOC (LOC = 1) for birds. 

Throughout this screening-level assessment, conclusions for birds are assumed to apply to 

terrestrial-phase amphibians and reptiles.

Acute dose-based RQs for mammals based on toxicity data for the rat (LD50 = 2,090 mg a.i./kgbw) are ≤0.01 for all existing and proposed uses of FPE and do not exceed the acute risk to listed 

(LOC = 0.1) or non-listed (LOC = 0.5) species LOCs. Chronic RQ values for mammals are 

presented in Table 4.6. Based on the rat chronic NOAEL of 9 mg/kg-bw/day (180 mg/kg-diet)

from exposure to fenoxaprop-ethyl, the chronic risk LOC (LOC = 1) is not exceeded for the grass 

grown from seed use for any size class of mammals or dietary item based on estimated dietary or 

dose-based concentrations. For the barley, conservation reserve, cotton, rice, and soybean uses, 

the chronic risk LOC is exceeded for dose-based estimates of small and/or medium sized mammals 

feeding on short grass. For the ornamentals and rights-of-way uses, the chronic risk LOC is 

exceeded for dose-based estimates of multiple size classes and dietary items. The potential for 

risk to mammals is further discussed in the Risk Description (Section 4.2).
-Page 61 of 116-

Table 4.6. Chronic RQ Values for Mammals of Different Size and Feeding Classes.

Crop Food Type

Dietary Based

RQs

Dose Based

RQs

(mammals)

All Size Classes Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Barley, wheat

Short grass 0.14 1.21 1.04 0.56

Tall grass 0.06 0.56 0.48 0.25

Broadleaf plants 0.08 0.68 0.58 0.31

Fruits/pods/seeds 0.01 0.08 0.06 0.03

Arthropods 0.05 0.48 0.41 0.22

Seeds N/A 0.02 0.01 0.01

Conservation Reserve

Short grass 0.13 1.16 0.99 0.53

Tall grass 0.06 0.53 0.45 0.24

Broadleaf plants 0.08 0.65 0.56 0.30

Fruits/pods/seeds 0.01 0.07 0.06 0.03

Arthropods 0.05 0.45 0.39 0.21

Seeds N/A 0.02 0.01 0.01

Cotton

Short grass 0.14 1.21 1.04 0.56

Tall grass 0.06 0.56 0.48 0.25

Broadleaf plants 0.08 0.68 0.58 0.31

Fruits/pods/seeds 0.01 0.08 0.06 0.03

Arthropods 0.05 0.48 0.41 0.22

Seeds N/A 0.02 0.01 0.01

Grass grown for seed

Short grass 0.11 0.96 0.82 0.44

Tall grass 0.05 0.44 0.38 0.20

Broadleaf plants 0.06 0.54 0.46 0.25

Fruits/pods/seeds 0.01 0.06 0.05 0.03

Arthropods 0.04 0.38 0.32 0.17

Seeds N/A 0.01 0.01 0.01

Ornamental, right-ofway, turf

Short grass 0.28 2.42 2.07 1.11

Tall grass 0.13 1.11 0.95 0.51

Broadleaf plants 0.16 1.36 1.16 0.62

Fruits/pods/seeds 0.02 0.15 0.13 0.07

Arthropods 0.11 0.95 0.81 0.43

Seeds N/A 0.03 0.03 0.02

Rice, Scenario 1

Short grass 0.11 0.97 0.83 0.44

Tall grass 0.05 0.44 0.38 0.20

Broadleaf plants 0.06 0.54 0.46 0.25

Fruits/pods/seeds 0.01 0.06 0.05 0.03

Arthropods 0.04 0.38 0.32 0.17

Seeds N/A 0.01 0.01 0.01

Rice, Scenario 2

Short grass 0.14 1.25 1.07 0.57

Tall grass 0.07 0.57 0.49 0.26

Broadleaf plants 0.08 0.70 0.60 0.32

Fruits/pods/seeds 0.01 0.08 0.07 0.04

Arthropods 0.06 0.49 0.42 0.22

Seeds N/A 0.02 0.01 0.01

Soybean, Scenario 1

Short grass 0.14 1.21 1.04 0.56

Tall grass 0.06 0.56 0.48 0.25

Broadleaf plants 0.08 0.68 0.58 0.31

Fruits/pods/seeds 0.01 0.08 0.06 0.03

Arthropods 0.05 0.48 0.41 0.22

Seeds N/A 0.02 0.01 0.01
-Page 62 of 116-

Crop Food Type

Dietary Based

RQs

Dose Based

RQs

(mammals)

All Size Classes Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Soybean, Scenario 2

Short grass 0.13 1.16 0.99 0.53

Tall grass 0.06 0.53 0.45 0.24

Broadleaf plants 0.08 0.65 0.56 0.30

Fruits/pods/seeds 0.01 0.07 0.06 0.03

Arthropods 0.05 0.45 0.39 0.21

Seeds N/A 0.02 0.01 0.01

Bold = Chronic risk LOC=1 exceeded.

4.1.2.2. Insect Pollinators

Based on the available data for young adult honey bees, both FPE TGAI and formulated FPE (HOE 

046360 24 EC15 A203; 12% FPE, 3.37% mefenpyr-diethyl) are classified as practically non-toxic 

to non-target insect pollinators on an acute contact exposure basis. The formulation 48-hour acute 

contact endpoint was much lower for the formulation (LD50 =58 μg a.i./bee) as compared to TGAI 

(LD50 >192.4 μg a.i./bee). The results of the TGAI acute oral and contact studies show no 

significant mortality to young adult (foraging) bees at any treatment level. Since the acute contact 

toxicity study for honeybees exposed to FPE TGAI was non-definitive (i.e., LD50 greater than 

highest concentration tested), RQs are not calculated. The risk to insect pollinators is discussed in 

greater detail in the Risk Description (Section 4.2). 

4.1.2.3. Terrestrial Plants

RQ values for terrestrial plants are calculated using the most sensitive endpoints for monocot and 

dicot species in vegetative vigor and seedling emergence tests with FPE typical end-use product 

(TEP) (Table 4.7). For all label uses of FPE, RQ values for monocot plants exposed to runoff and 

drift exceed the non-listed species LOC (LOC =1). Conversely, RQ values for non-listed dicot 

plants exposed to spray drift range from <0.01 to 0.37 across the labeled uses of FPE evaluated

and do not exceed the risk to non-listed species LOC (LOC =1).

RQ values are not calculated for listed monocot or dicot species exposed to runoff or drift because 

a definitive NOAEC was not available from the submitted seedling emergence tests with TEP. In 

addition, RQ values are not calculated for non-listed dicots due to runoff because a definitive EC25

was not available from the submitted seedling emergence tests with TEP (i.e., no dicot 

species/endpoints were inhibited by 25% or more at the application rates used). The potential for 

risk to listed and non-listed species of terrestrial and semi-aquatic plants from exposure to 

formulated FPE is discussed in greater detail in the Risk Description (Section 4.2). 

For purposes of comparison, RQs were also derived using TERRPLANT default ground and aerial 

spray drift assumptions of 1 and 5%, respectively (Table 4.7), in addition to using the more 

realistic PRZM-EXAMS spray drift values. Results are similar using the different spray drift 

values except that non-listed LOC for monocots is not exceeded for spray drift from ground spray

using the default TERRPLANT drift values.
-Page 63 of 116-

Table 4.7. Non-listed RQs for Monocots Inhabiting Dry and Semi-Aquatic Areas Exposed to FPE via Runoff 

and Drift.

Use

Application 

Rate

(lbs a.i./A)

Application 

Method

Drift 

Value (%)

Spray drift 

RQ

Dry area 

RQ

Semi-aquatic 

area RQ

Barley, wheat, 

cotton, soybean 0.105 GroundAerial

6 (1)

12.5 (5)

3.15 (0.53)

6.56 (2.63)

3.68 (1.05)

7.09 (3.15)

8.40 (5.78)

11.8 (7.88)

Conservation 

Reserve 0.10 GroundAerial

6 (1)

12.5 (5)

3.00 (0.05)

6.25 (2.50)

3.50 (1.00)

6.75 (3.00)

8.00 (5.50)

11.3 (7.50)

Ornamental, rightof-way, turf 0.173 Ground 6 (1) 5.19 (0.87) 6.06 (1.73) 13.8 (9.52)

Rice 0.108 Ground

Aerial

6 (1)

12.5 (5)

3.24 (0.54)

6.75 (2.70)

3.78 (1.08)

7.29 (3.24)

8.64 (5.94)

12.2 (8.10)

Grass grown for 

seed 0.083 Ground 6 (1) 2.49 (0.42) 2.91 (0.83) 6.64 (4.57)

N/A = not applicable

Bolded RQ values exceed the level of concern for risk to plants (LOC = 1).

1 RQ values are not calculated for listed species because the NOAEC values from the seedling emergence study 

were non-definitive, and the data were not suitable to calculate EC05 values. The potential for risk to listed species 

in dry and semi-aquatic areas is discussed further in the Risk Description (Section 4.2).

4.1.3 Refinements

Aquatic EECs from Rice Use

Screening-level EECs for rice use, estimated with the Tier I Rice Model, resulted in RQ values 

that exceed the acute risk LOC for freshwater aquatic vertebrates and estuarine/marine 

invertebrates. In an effort to refine these estimates, rice applications were evaluated using the 

Pesticide Flooded Application Model (PFAM, version 1.05, September 2013). The model 

simulates two linked compartments: a water column and a sediment zone (benthos). Each 

compartment is completely mixed and at internal equilibrium with respect to sorption of the 

chemical (USEPA, 2004). Pesticide moves between the compartments via a time-limited, firstorder mass-transfer process. The model accounts for hydrolysis, photolysis, and metabolism in 

water, sediment, and soil (when no water is present), as well as sorption and volatilization. Water, 

sediment, and pesticide may flow out of the flooded field. Changes in water body conditions 

(temperature, water levels, wind speed, etc.) and resulting changes in degradation rates occur on a 

daily time step. Pesticide application and flooding sequences are mapped onto the time series in 

1-year cycles for the length of a simulation (30 years). 

Detailed information on the PFAM inputs used to model rice applications for FPE is provided in 

Appendix G. According to FPE labels, applications should occur at the 4-leaf stage to late tillering 

stage. According to the 2012 Arkansas Rice Quick Facts, pretillering (1st leaf to 4th leaf stage) 

occurs approximately 15-25 days after planting, while tillering can occur 24 to 42 days after 

planting. Based on this information, the first FPE application was scheduled to occur 28 days after 

planting and the second application was scheduled to occur 14 days later (42 days after planting). 

Flood waters were released 60 days after the second FPE application to permit the estimation of 

21-day and 60-day aquatic EECs in the paddy water. As the label allows for three applications of 

FPE, but only two applications during the growing season, the third FPE application was scheduled 

to occur 7 days after harvest. For post-flood applications, FPE labels specify that the “water level 

should cover no more than 25% of the annual grass weed foliage. The flood may be increased to a 
-Page 64 of 116-

normal depth (i.e., the paddy depth prior to FPE application) 2 to 3 days after application.” Based 

on this information, fill levels were decreased to 1 inch (0.0254 m) the day prior to an application 

and were increased to 4 inches (0.1016 m) 2 days after application.

Results of the refined modeling are provided in Table 4.8. The 1-in-10-year 1-day average release 

concentrations and paddy concentrations are used to assess acute and chronic impacts to freshwater 

vertebrates that may dwell in rice paddies. Based on concentrations of FPE in release water from 

rice paddies, acute RQs for freshwater vertebrates are all below 0.01 and therefore do not exceed 

the acute risk to listed species LOC (LOC = 0.05). Acute RQs for freshwater vertebrates based on 

FPE concentrations in paddy water drawn down to a depth of 1 inch (e.g., to achieve a water level 

such that no more than 25% of the annual grass weed foliage is covered) range from 0.19 to 0.34

and exceed the risk to listed species LOC (LOC = 0.05). Acute RQs for freshwater vertebrates 

based on FPE concentrations in paddy water at ≥4 inches are below 0.01 and do not exceed the 

LOC for risk to listed (LOC = 0.05) or non-listed (LOC = 0.5) species. Therefore, refinement of 

acute rice paddy concentrations of FPE using PFAM alleviates potential concern for freshwater 

vertebrates for all rice scenarios except in cases where listed species occupy rice paddies drained 

down to a depth of 1 inch.

The 1-in-10-year 1-day average release concentration is also used to assess impacts to 

estuarine/marine invertebrates and aquatic plants in water bodies receiving discharges from rice 

paddies. Based on these concentrations, refined acute RQs for estuarine/marine invertebrates are 

below 0.01 and do not exceed the acute risk LOCs for listed (LOC = 0.05) or non-listed (LOC = 

0.5) species, as was the case in the screening-level analysis for estuarine/marine invertebrates. For 

aquatic plants, listed species RQs calculated using the refined rice exposure values no longer 

exceed the listed species LOC (LOC=1) for aquatic plants.

Table 4.8. Refined Aquatic Exposure Modeling Results for Rice Use.

Scenario State

1-in-10-year 

1-day average 

concentration 

(μg/L)

1-in-10-year 1-day average 

concentration1

1-in-10-year 1-day average 

concentration2

Max

(μg/L)

21-day

(μg/L)

60-day

(μg/L)

Max

(μg/L)

21-day

(μg/L)

60-day

(μg/L)

Tier 1 Rice Model -- -- -- -- 83 0.91 0.32

1

(0.71, 

0.71, 

0.046)

AR 0.0010 96 10.1 3.5 0.86 0.08 0.03

CA 0.0017 105 11.4 4.0 1.12 0.11 0.04

LA 0.0005 86 8.8 3.1 0.47 0.05 0.02

MS 0.0004 86 8.7 3.0 0.45 0.04 0.02

TX 0.0006 89 9.2 3.2 0.55 0.05 0.02

2

(0.108, 

0.034, 

0.046)

AR 0.0015 147 10.7 3.7 1.32 0.09 0.03

CA 0.0026 156 11.6 4.1 1.64 0.13 0.04

LA 0.0008 132 9.2 3.2 0.70 0.05 0.02

MS 0.0007 131 9.0 3.2 0.69 0.05 0.02

TX 0.0010 135 9.5 3.3 0.83 0.06 0.02

1

Includes concentrations in 1inch paddy water during draw down. Max generally occurs after 2nd application in 1 

inch of water.

2 Values obtained only from concentrations where the paddy depth ≥ 4 inches.
-Page 65 of 116-

4.2. Risk Description

4.2.1. Risks to Aquatic Organisms

RQ calculations for aquatic organisms in this assessment only reflect surface water exposures. 

Although groundwater EECs were estimated in this assessment, they are much lower than 

estimated surface water concentrations and therefore not expected to significantly impact the risk 

conclusions for aquatic organisms exposed to FPE.

4.2.1.1. Freshwater Vertebrates and Invertebrates

Based on screening level exposure estimates generated by PRZM/EXAMS and the Tier I Rice 

model, only the acute risk to listed species LOC (LOC = 0.05) was exceeded for freshwater 

vertebrates. Refinement of acute rice paddy concentrations of FPE using PFAM indicated that 

there is only a potential concern for listed freshwater vertebrates inhabiting rice paddy water drawn 

down to 1 inch, should such organisms exist.

Based on available information, FPE transformation products appear to be less toxic to freshwater 

vertebrates than the parent on an acute exposure basis. Therefore the inclusion of degradates 

residues in exposure estimates is not supported. Formulations also do not appear to be 

substantially (more than an order of magnitude) more toxic to freshwater vertebrates than the 

parent on an acute exposure basis.

RQ values for acute risk to freshwater invertebrates were based on toxicity data from fenoxapropethyl since the available acute toxicity endpoint for FPE is non-definitive (D. magna EC50 >1,058 

μg a.i./L). The inability to determine a definitive endpoint for FPE on freshwater invertebrates is 

a result of solubility limitations (FPE water solubility: 0.7 mg/L). LOCs for acute risk to listed 

and non-listed freshwater invertebrates were not exceeded for any labeled uses of FPE. If peak 

surface water EECs from the assessed uses (Table 3.5) are compared to the non-definitive acute 

toxicity endpoint for Daphnia exposed to FPE TGAI, no Agency LOCs would be exceeded. 

Therefore, the potential for acute risk to freshwater invertebrates from exposure to technical grade 

FPE for labeled uses is considered to be low.

Life cycle studies of D. magna performed with FPE formulations showed five to 100 times greater 

sensitivity (NOAEC range: 0.0023-0.042 mg a.i./L) as compared to a TGAI study with FPE 

(NOAEC = 0.23 mg a.i./L). The higher toxicity exhibited by the formulations does not appear to 

be driven by the co-formulated active ingredient mefenpyr-diethyl (PC Code 811800; plant 

safener) since three studies with FPE combined with mefenpyr-diethyl resulted in lower toxicity 

(i.e., less sensitive) as compared to a formulation (HOE 046360 OH EW07 A209) with FPE alone 

(Table 3.10). In addition, an acute study with Daphnia conducted with mefenpyr-diethyl TGAI 

(MRID 43972208; EC50=52 mg a.i./L) does not provide evidence that the plant safener is more 

toxic to freshwater invertebrates as compared to FPE (Daphnia EC50 >1.1 mg a.i./L). Currently, 

only acute toxicity data for formulations are used by EFED to estimate effects to aquatic organisms 

resulting from spray drift. Chronic exposures and potential risk resulting from spray drift of the 

formulation are generally not considered, since components of a formulation are assumed to have 

different fate and transport properties than the active ingredient (e.g., mobility, affinity to soil 
-Page 66 of 116-

versus water, degradation kinetics). Consequently, it is not possible to assess the impact of these 

differences on the concentration of the formulated product as a function of time. Therefore, 

although formulations containing FPE appear to be substantially more toxic than FPE TGAI, this 

is not applied in a risk context in this assessment. Therefore, chronic exposures to formulations

could theoretically result in concern, but based on the current use pattern and available fate 

information for FPE, prolonged exposures to aquatic organisms are not anticipated.

4.2.1.2. Estuarine/Marine Fish and Invertebrates

RQ values for estuarine/marine fish are not presented in the Risk Estimation because the available 

acute toxicity endpoint is non-definitive (sheepshead minnow LC50 >1,000 μg a.i./L) and no 

chronic toxicity data have been submitted. To characterize the potential for acute risk to 

estuarine/marine fish associated with the labeled uses of FPE, peak surface water EECs are 

compared to the non-definitive acute toxicity endpoint for sheepshead minnow. EECs for all uses 

are less than the acute risk LOC for listed species except for applications to rice (RQ =0.08). Given 

that the estimated release water concentrations from PFAM are several orders of magnitude below 

the Tier I Rice model EECs, the likelihood of acute mortality in listed or non-listed 

estuarine/marine fish from exposure to technical grade FPE is expected to be low.

In the absence of chronic toxicity data for estuarine/marine fish, the freshwater fish ACR (11.4, 

fathead minnow) and the acute toxicity data for sheepshead minnow (>1.0 mg/L) were used to

estimate a chronic NOAEC value of 88 μg a.i./L. A comparison of the 60-day EECs to this chronic 

endpoint indicates that the chronic risk LOC is not exceeded for any labeled used of FPE.

RQ values for estuarine/marine invertebrates exposed to the TGAI are below the LOCs for acute 

risk to listed (LOC = 0.05) and non-listed (LOC = 0.5) species for all labeled uses except for rice.

When concentrations of FPE released from rice paddies into the estuarine/marine environment are 

refined using PFAM, Agency LOCs are no longer exceeded. Therefore, based on these 

refinements, the likelihood of acute mortality to listed or non-listed estuarine/marine invertebrates 

from exposure to technical grade FPE for labeled uses is considered low.

No chronic risks of concern for estuarine/marine invertebrates were identified for any labeled use.

4.2.1.3. Sediment Dwelling Aquatic Invertebrates

The sensitivity of benthic freshwater and estuarine/marine invertebrates to FPE has previously 

been raised as an uncertainty because ecotoxicity data typically used by EFED to evaluate effects 

to sediment-dwelling organisms (e.g., non-biting midges, amphipods) have not been submitted. 

This was considered an important uncertainty in a 2011 data gap clarification memo submitted by 

EFED (US EPA 2011) given the potential for FPE to partition to sediments with a log Kow greater 

than 3 and a KFOC greater than 100 L/kgoc. In addition, FPE is moderately to very highly toxic to 

aquatic animals on an acute exposure basis. However, FPE degrades rapidly in the aquatic 

environment and, based on the soil and aquatic metabolism studies, the metabolite residues 

(fenoxaprop-p acid and chlorobenzoxazolone) are expected to form primarily within the water 

column, and then to diffuse into the sediments. Peak pore water EECs for FPE are several orders 

of magnitude lower than the most sensitive water column animal tested with FPE on an acute 
-Page 67 of 116-

exposure basis (i.e., mysid shrimp; LC50 = 0.11 mg a.i./L), as well as benthic invertebrate acute 

toxicity data from crayfish exposed to FE (Procambarus simulans LC50 = 1.1 mg a.i./L). 

Therefore, risks of concern are not expected for sediment-dwelling organisms exposed to FPE. In 

addition, since degradates appear to be less toxic than the parent to aquatic organisms in general, 

the potential for adverse effects to sediment-dwelling organisms from FPE is considered low.

4.2.1.3. Aquatic Plants

The RQs for labeled uses of FPE are below the LOC (LOC =1) for risk to listed vascular and nonlisted nonvascular species of aquatic plants. Only the rice use exceeded the LOC for risk to listed, 

nonvascular aquatic plants (RQ = 3.09). However, when concentrations of FPE released from rice 

paddies into the aquatic environment are refined using PFAM, the risk to listed species LOC 

(LOC=1) is no longer exceeded for rice. To characterize the potential for risk to non-listed 

vascular plants associated with the labeled uses of FPE, peak surface water EECs are compared to 

the non-definitive toxicity endpoint for duckweed (IC50 >3,000 μg a.i./L). EECs for all uses are 

less than LOC for risk to non-listed species. Therefore, the likelihood of adverse effects on aquatic

plants from exposure to FPE is expected to be low.

4.2.2. Terrestrial Organisms

4.2.2.1. Birds

Acute and chronic risks to birds based on acute oral and chronic dietary toxicity data, respectively, 

are low for all labeled uses of FPE. On a sub-acute dietary exposure basis, because no mortality 

was observed at the highest treatment levels tested, RQ values for sub-acute exposures were not 

calculated in the Risk Estimation section of this assessment. For the labeled uses of FPE, the 

maximum dietary-based EEC of 97 mg/kg-diet (short grass) is approximately 2% of the treatment 

levels where no mortality and/or sublethal effects were observed in the sub-acute dietary avian 

study (LC50 >4220 mg/kg diet). For birds, an acute EEC that exceeds 10% of the effects threshold 

exceeds the Agency’s LOC for acute risk to listed species. Therefore, the potential for risk to 

listed and non-listed species of birds is expected to be low. Passerine species may be more

sensitive to FPE exposure than the bobwhite quail and mallard duck; in the absence of ecotoxicity 

data for passerine birds, risk to these species cannot be precluded; however, there are also no

available data to indicate that risks to this group are likely.

4.2.2.2. Mammals

Dose-based RQ values did not exceed the acute risk to listed species LOC (LOC =0.1) or nonlisted species (LOC =0.5) for any size mammals. Therefore, the labeled uses of FPE are not 

expected to result in acute risk to listed or non-listed mammals.

Chronic dietary and dose-based RQ values based on rat two-generation study data from FE indicate 

a potential for risks of concern to mammals associated with at least one size class or dietary item

for all labeled uses except for grass grown for seed, for which the chronic LOC was not exceeded 

for any size class or dietary item. Exposure and risk are expected to be greatest for mammals that 

consume short grass. For each of the labeled uses, to achieve both dietary- and dose-based RQs 
-Page 68 of 116-

that do not exceed the chronic LOC for any of the given categories of mammals, the application 

would need to be limited to a single application rate of approximately 0.085 lbs a.i./A.

Additional characterization of the potential for mammalian chronic risk was performed by 

inputting average use rates for several labeled uses of FPE as reported by BEAD (barley and spring 

wheat: 0.061 lbs a.i./A; winter wheat: 0.059 lbs a.i./A; cotton: 0.035 lbs a.i./A; rice: 0.09 lbs a.i./A; 

soybean: 0.033 lbs a.i./A). Based on average application rates and upper-bound exposure values, 

only the use on rice exceeded the chronic risk LOC (LOC=1) for small mammals feeding on short 

grass (RQ=1.04). It should be noted that average use rates were not available for ornamental or 

rights-of-way uses.

There is uncertainty surrounding chronic risk of FPE to mammals since chronic toxicity data were 

bridged from FE, which is indicated as being more toxic to mammals than FPE in Section 4.1 of 

the HED human health risk assessment for FPE (US EPA 2014). There is additional uncertainty 

in the chronic mammal risk estimation since the standard rat two-generation toxicity endpoint used 

to calculate RQs in this assessment (NOAEL = 9 mg/kg/day) is approximately 20 times higher 

(less sensitive) than available data from a two-year feeding study in dogs (NOAEL = 0.375 

mg/kg/day) in which reduced body weight (10-13%) and reduced body weight gain (46-51%) were 

observed at the LOAEL (1.875 mg/kg/day) relative to controls. However, given that FE is 

generally more toxic to mammals than FPE, and given that available rat two-generation data are 

typically used to calculate RQs in EFED risk assessments (US EPA, 2004), the endpoint reported 

for dogs was not considered appropriate for calculating RQs and is likely to be overly conservative 

for estimating risk for FPE. In addition, it should be noted that the rat two-generation NOAEL for 

FE is based on the highest concentration tested in the study (9 mg/kg/day) since no significant 

adverse effects were observed, indicating that this endpoint is also potentially conservative since 

no LOAEL was established.

4.2.2.3. Insect Pollinators

Based on the available data for young adult honey bees, both FPE TGAI and formulated FPE (HOE 

046360 24 EC15 A203; 12% FPE, 3.37% mefenpyr-diethyl) are classified as practically non-toxic

to non-target terrestrial invertebrates on an acute contact exposure basis. However, the 48-hour 

acute contact endpoint was much lower (i.e., more toxic) for the formulation (LD50 =58 μg a.i./bee) 

as compared to TGAI (LD50 >192.4 μg a.i./bee). The results of the TGAI acute oral and contact 

studies show no significant mortality to young adult (foraging) bees at any treatment level. Since 

the acute contact toxicity study for honeybees exposed to FPE TGAI was non-definitive (i.e., LD50

greater than highest concentration tested), RQs were not calculated for terrestrial invertebrates. 

However, it should be noted that estimated exposure to arthropods across labeled uses of FPE 

range from 7.8 to 38 mg a.i./kg-arthropod, which is several orders of magnitude lower than the 

highest concentration tested in the acute contact honeybee study (192.4 μg a.i./bee converted to 

1,500 mg/kg-bee based on an estimated weight of 0.128 g/bee).

The only known incident involving terrestrial invertebrates potentially related to FPE occurred in 

2009, in which mortalities were observed in approximately 320 bee hives in Box Elder, UT 

following application of fenoxaprop-ethyl (application method was not specified). Based on the 

available information, it is difficult to reconcile the occurrence of this incident with the acute 
-Page 69 of 116-

toxicity profile of FPE. The incident did not occur with FPE but rather with fenoxaprop-ethyl 

which is a racemate of FPE. There is some indication that formulation contents may increase 

toxicity of FPE to honeybees, so it is possible that the incident could be linked to formulation 

components or surfactants that could incapacitate bees. Overall, there are not multiple lines of 

evidence indicating risk to terrestrial invertebrates for labeled uses of FPE. However, there is 

uncertainty regarding the toxicity of FPE to honeybee larvae since no data on this developmental 

state of honey bees were available at the time of this review.

4.2.2.4. Terrestrial Plants

Due to the lack of a definitive NOAEC for monocots from available seedling emergence and 

vegetative vigor studies, and the lack of definitive EC25 and NOAEC values for dicots from 

available seedling emergence studies, RQ values could not be calculated for listed monocot or 

dicot species due to runoff or drift as well as non-listed dicot species due to runoff. If RQs were 

calculated using non-definitive endpoint values listed in Table 3.13, listed species RQs for 

monocots and dicots would range from 8.3 to 46 and <0.1 to 0.34, respectively, across labeled uses 

of FPE3.In addition, RQs for non-listed dicots exposed to runoff would range from <0.1 to 0.34

across label uses of FPE and would not exceed LOCs.

3

Based on the available terrestrial plant toxicity data, including non-definitive endpoints, there is 

evidence that all label uses of FPE pose risks of concern for listed and non-listed monocots. This 

is supported by a number of incidents reported on grain crops treated with FPE. Conversely, risks

of concern to listed and non-listed dicot plants are not indicated for any label uses of FPE.

However, it should be noted that there is some uncertainty surrounding risks to listed dicots since 

the NOAEC from the available vegetative vigor study is non-definitive (<0.081 lbs a.i./A) and 

could potentially be much lower (more toxic). In addition, there are also some uncertainties in 

potential effects to non-listed dicots (and in some cases monocots) since EC25 values for most dicot 

species (and some monocots) were only tested up to an application rate of 0.081 lbs a.i./A, which 

is lower than the maximum label use rate of 0.173 lbs a.i./A for several uses.

The AgDRIFT model was used to estimate how far downwind from the treatment site spray drift 

exposure might occur at levels known to inhibit plant growth. The screening-level analysis was

based on the most sensitive monocot and dicot plant species tested. The results suggest that spray 

drift from aerial and ground spray applications for various labeled uses of FPE may result in 

potential effects on non-target dicot plants within 0 to 13 feet of the treatment area. By contrast, 

for monocots (given their greater sensitivity to FPE), effects across labeled uses of FPE are 

expected at much greater distances from the treatment area, ranging from 85 to 548 feet for ground 

applications and 305 to >1,000 feet for aerial applications. The actual effects area may be larger 

because the submitted data on both monocots and dicots do not establish a lower bound of effects 

(NOAEL) for some species of plants. The contribution of runoff may further extend the potential

effects area for non-target plants. The spray drift analysis for terrestrial plants for FPE is presented 

in (Table 3.14).

 

3 RQ calculations based on ground and aerial spray drift fractions of 6 and 12.5%, which are considered more 

environmentally relevant.
-Page 70 of 116-

Labels for FPE have varying specifications with regards to droplet size distributions. Some 

indicate that the product should be applied using nozzles and pressures that generate a “Medium”

spray droplet size category. Other labels are more specific, indicating that nozzles should provide 

200-350 micron (Reg. No. 264-666) or 150-300 micron (Reg. No. 264-647) size droplets. Other 

products do not specify the drop size distribution. For aerial applications, EFED used the

American Society of Agricultural and Biological Engineers (ASABE, formerly ASAE) Fine-toMedium droplet size category in its modeling. This droplet size category is EFED’s default 

assumption when labels do not specify application parameters. The volume median diameter 

(Dv50) for the Fine-to-Medium droplet size distribution is 255 microns, which falls within the 

requirements specified on certain labels as discussed above. For ground applications, EFED used

the ASABE Very Fine-to-Fine droplet size category. Again, this droplet size category is EFED’s 

default, employed in modeling when labels do not specify application parameters for ground 

applications. The Dv50 for the Very Fine-to-Fine droplet size distribution is 175 microns, which 

falls within the requirements specified on certain labels as discussed above. For uses of FPE,

smaller buffers would be needed to protect non-target organisms if the labels specified a coarser 

droplet size distribution.

Table 4.11. Possible1 Effects Distance for Nontarget Terrestrial Plants Exposed to FPE through Spray Drift 

Only Based on the Most Sensitive Crop Species in Submitted Toxicity Studies.

Crop

Single 

Max. 

App. 

Rate

(lbs 

a.i./A)

AgDRIFT 

Scenario

Distance from Treatment Site (feet)

Monocots

corn

IC25 = 

0.0025 lbs 

a.i./A

Monocots

Corn 

NOAEL

<0.0006 lbs 

a.i./A

Dicots

Carrot

IC25 = 

0.058 lbs 

a.i./A

Dicots

Carrot

NOAEL = 

0.041 lbs 

a.i./A

Barley/wheat1 0.105 Aerial spray

Ground spray

384

105

> 1,000

378

0

7

6

6

Conservation 

reserve

0.1 Aerial spray

Ground spray

364

102

> 1,000

361

0

3

7

6

Cotton, soybeans 0.105 Aerial spray

Ground spray

384

105

> 1,000

378

0

7

6

6

Ornamental, 

right-of-way, turf 0.173 Ground spray 171 548 10 13

Rice 0.108 Aerial spray

Ground spray

394

108

> 1,000

384

0

7

7

6

Grass grown for 

seed 0.083 Aerial sprayGround spray

305

85

> 1,000

312

0

3

0

4

1 While the application rate during the growing season is 0.083 lbs a.i./A, 0.105 lbs a.i./A can be applied after the 

growing season.

If FPE were applied via aerial and ground spray using a Medium-to-Coarse droplet size category, 

the buffer zones would be reduced as follows
-Page 71 of 116-

Table 4.12. Possible1 Effects Distance for Nontarget Terrestrial Monocot Plants Exposed to FPE through 

Spray Drift Only Based on Medium-Coarse Droplet Size.

Crop

Single 

Max. 

App. 

Rate

(lbs 

a.i./A)

AgDRIFT 

Scenario

Distance from Treatment Site (feet)

Monocots

corn

IC25 = 

0.0025 lbs a.i./A

Monocots

Corn 

NOAEL

<0.0006 lbs a.i./A

Barley/wheat1 0.105 Aerial spray

Ground spray

207

23

886

131

Conservation 

reserve

0.1 Aerial spray

Ground spray

197

23

817

121

Cotton, soybeans 0.105 Aerial spray

Ground spray

207

23

886

131

Ornamental, 

right-of-way, turf 0.173 Ground spray 40 236

Rice 0.108 Aerial spray

Ground spray

210

23

928

135

Grass grown for 

seed 0.083 Aerial sprayGround spray

171

20

620

98

4.3. Conclusions

 

For aquatic organisms, the screening-level assessment with preliminary refinements concludes that 

the use of FPE in accordance with current and proposed labels results in potential acute risks of 

concern for listed freshwater vertebrates (fish and aquatic-phase amphibians) inhabiting rice 

paddies when paddy water is drained down to 1 inch; the likelihood of such a scenario is considered 

low. Additional screening-level risks of concern to aquatic organisms for the labeled use on rice 

were alleviated by refinements in the modeling of residue concentrations in rice paddy water and 

in water released from paddies. Although several chronic toxicity studies with freshwater 

invertebrates indicate that formulations containing FPE may be two orders of magnitude more 

toxic than FPE technical grade active ingredient (TGAI), the components of a formulation are 

assumed to have different fate and transport properties from the active ingredient (e.g., mobility, 

affinity to soil versus water, degradation kinetics). Consequently, aquatic organisms are not 

expected to be chronically exposed to the formulation, and therefore, the scenario is not assessed 

in this analysis. 

For terrestrial organisms, no acute or chronic risks of concern are identified for birds, as well as 

terrestrial phase amphibians or reptiles, for which birds serve as surrogates. For mammals, the 

chronic risk level of concern (LOC) is not exceeded for the grass grown from seed use for any size 

class or dietary item based on estimated dietary or dose-based concentrations. For the barley, 

conservation reserve, cotton, rice, and soybean uses, the chronic risk LOC is exceeded for dosebased estimates of small and/or medium sized mammals feeding on short grass. For the 

ornamentals and rights-of-way uses, the chronic risk LOC is exceeded for dose-based estimates of 

multiple size classes and dietary items. This assessment also indicates that all labeled uses of FPE 

pose potential risks of concern to listed and non-listed monocotyledonous (monocot) terrestrial 

plants, which is supported by a series of incidents reported for grain crops treated with FPE. These 

results also indicate that large spray drift buffer distances (85 to >1,000 feet) may be needed to 

protect non-target monocot plants from effects from spray drift. It is possible that specifying a 
-Page 72 of 116-

coarser droplet size on the label would help decrease the distance necessary for the efficacy of 

such buffers.

4.4 Uncertainties

FPE is the R-enantiomer (or d-isomer) of the racemate fenoxaprop-ethyl. Because the chirality is 

maintained during the degradation to fenoxaprop-p acid, fenoxaprop-p acid is also an enantiomer. 

Further degradation to 4-(6-chloro-2-benzoxazolyloxy)phenol) and chlorobenzoxazolone results 

in the loss of chirality. While enantiomers of chiral substances tend to have the same 

physicochemical properties, their biochemical activities, unlike abiotic transformations, can be 

quite different because of enantiomer selectivity of biochemical processes (Muller & Kohler, 

2004). Enantiomer-specific chemical analysis in fate studies show low enantiomer-selective 

degradation (S:R < 0.02) occurred for FPE, but that some enantiomer-selective degradation (S:R 

0.09 to 0.27) occurred for fenoxaprop-p acid. The higher S:R ratios in selected fate studies may 

indicate preferential degradation of the S enantiomer of fenoxaprop-p acid or enantiomerization of 

the R enantiomer of fenoxaprop-p acid to the S enantiomer fenoxaprop-p acid. There is uncertainty 

in the exact process leading to the higher enantiomeric S:R ratios of fenoxaprop-p acid.

There is some uncertainty surrounding risks to listed dicotyledonous plants since the NOAEC from 

the available vegetative vigor study is non-definitive (<0.081 lbs a.i./A) and could potentially be 

much lower (more toxic). 

5. Listed Species of Concern

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2), requires all federal 

agencies to consult with the National Marine Fisheries Service (NMFS) for marine and 

anadromous listed species, and/or the United States Fish and Wildlife Service (USFWS) for listed 

wildlife and freshwater organisms, if they are proposing an "action" that may affect listed species 

or their designated critical habitat. Each federal agency is required under the Act to ensure that 

any action they authorize, fund, or carry out is not likely to jeopardize the continued existence of 

a listed species or result in the destruction or adverse modification of designated critical habitat. 

To jeopardize the continued existence of a listed species means "to engage in an action that 

reasonably would be expected, directly or indirectly, to reduce appreciably the likelihood of both 

the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, or 

distribution of the species" (50 C.F.R. § 402.02).

To facilitate compliance with the requirements of the Endangered Species Act (subsection (a)(2)), 

the Office of Pesticide Programs has established procedures to evaluate whether a proposed 

registration action may directly or indirectly appreciably reduce the likelihood of both the survival 

and recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution 

of any listed species (USEPA 2004). After the Agency’s screening-level risk assessment is 

conducted, if any of the Agency’s listed species LOCs are exceeded for either direct or indirect 

effects, an analysis is conducted to determine if any listed or candidate species may co-occur in 

the area of the proposed pesticide use or areas downstream or downwind that could be 

contaminated from drift or runoff/erosion. Given the existing national registrations and broad 

range of registered uses for FPE, the Agency has determined that listed species may be present in 
-Page 73 of 116-

the action area. If listed or candidate species may be present in the action area, further biological 

assessment is undertaken. The extent to which listed species may be at risk is considered, which 

then determines the need for the development of a more comprehensive consultation package, as 

required by the Endangered Species Act. The federal action addressed herein is the registration

review of existing uses for FPE.

5.1. Action Area

For listed species assessment purposes, the action area is considered to be the area affected directly 

or indirectly by FPE use and not merely the immediate area where FPE is applied. At the initial 

screening-level, the risk assessment considers broadly described taxonomic groups and 

conservatively estimates exposure for organisms that are co-located with the pesticide treatment 

area. This means that terrestrial plants and wildlife are assumed to be located on or adjacent to the 

treated site and aquatic organisms are assumed to be located in a surface water body adjacent to 

the treated site, except in the case of direct application to potential aquatic habitat (e.g., rice

paddies).

5.2. Taxonomic Groups Potentially at Risk 

If the assumptions associated with the screening-level action area result in RQs that are below the 

listed species LOCs, a "no effect" determination conclusion is made with respect to listed species 

in the relevant taxa, and no further refinement of the action area is necessary. Furthermore, RQs 

below the listed species LOCs for a given taxonomic group indicate no concern for indirect effects 

on listed species that depend upon the taxonomic group for which the RQ was calculated. 

However, in situations where the screening assumptions lead to RQs in excess of the listed species 

LOCs for a given taxonomic group, a potential for a "may affect" conclusion exists and may be 

associated with direct effects on listed species belonging to that taxonomic group or may extend 

to indirect effects upon listed species that depend upon that taxonomic group as a resource. In 

such cases, additional information on the biology of listed species, the locations of these species, 

and the locations of use sites are considered to determine the extent to which screening 

assumptions regarding an action area apply to a particular listed organism. These subsequent 

refinement steps will consider how this information would impact the action area for a particular 

listed organism and potentially include areas of exposure that are downwind and downstream of 

the pesticide use site.

Assessment endpoints, exposure pathways, the conceptual models addressing FPE uses, and the 

associated exposure and effects analyses conducted for the FPE screening-level risk assessment 

are in Sections 2 to 3. The assessment endpoints used in the screening-level risk assessment 

include those defined operationally as reduced survival and reproductive impairment for both 

aquatic and terrestrial animal species and survival, reproduction, and growth of aquatic and 

terrestrial plant species from both direct acute and chronic exposures. These assessment endpoints 

address the standard set forth in the Endangered Species Act requiring federal agencies to ensure 

that any action they authorize does not appreciably reduce the likelihood of both the survival and 

recovery of a listed species in the wild by reducing the reproduction, numbers, or distribution of 

the species. Risk estimates (RQs), integrating exposure and effects, are calculated for broad based 

taxonomic groups in the screening-level risk assessment presented in Section 4.
-Page 74 of 116-

Data on exposure and effects collected under laboratory and sometimes field conditions are 

evaluated in the screening-level risk assessment for non-listed and listed species. Both acute and 

chronic risk to listed species LOCs are considered to identify potential effects (or absence thereof) 

to listed species. This section identifies potential direct effect concerns, by taxa, that are triggered 

by exceeding risk to listed species LOCs in the screening-level risk assessment (Table 5.1). Where 

applicable, an evaluation of the probability of individual effects for exposures that may occur at 

the established risk to listed species LOC for each taxon is presented in Section 4. Table 5.1

further identifies taxa for which the potential risk to individual listed species is uncertain due to 

data gaps or limitations in study design. These uncertainties may be reduced or resolved by 

additional data, but physiological constraints in achieving higher dose levels than the standard 

limit dose should be considered when determining the need for further acute toxicity testing.

Table 5.1. Potential Effects to Federally-Listed Taxa Associated with Direct or Indirect Effects from the 

Labeled Uses of FPE.

Listed Taxon Direct 

Effects

Uses of Concern for 

Direct Effects

Indirect Effects to 

Listed Taxon 

through Direct 

Effects on ...

Uses of Concern

for Indirect Effects

Terrestrial and semiaquatic plants -

monocots

Yes All uses6 MammalsC

All uses (except 

grass grown for 

seed)

Terrestrial and semiaquatic plants - dicots No None Plants2

, MammalsC All uses

Terrestrial invertebrates No None Plants1,2 All uses

Birds No None Plants1,2 All uses

Terrestrial-phase 

amphibians No None Plants1,2 All uses

Reptiles No None Plants1,2 All uses

Mammals YesC All uses (except grass 

grown for seed)5 Plants1,2 All uses

Aquatic plants No None Plants1,2 All uses

Freshwater fish No7 None Plants1,2 All uses

Aquatic-phase 

amphibians5 No None Plants1,2 All uses
-Page 75 of 116-

Listed Taxon Direct 

Effects

Uses of Concern for 

Direct Effects

Indirect Effects to 

Listed Taxon 

through Direct 

Effects on ...

Uses of Concern

for Indirect Effects

Freshwater 

invertebrates No None Plants1,2 All uses

Marine/estuarine fish5 No None Plants1,2 All uses

Marine/estuarine 

invertebrates No None Plants1,2 All uses

C Chronic risk.

1 Terrestrial and semi-aquatic dicot plants.

2 Terrestrial and semi-aquatic monocot plants.

3 Birds serve as a surrogate for terrestrial-phase amphibians and reptiles.

4 Freshwater fish serve as a surrogate for aquatic-phase amphibians.

5 For the barley, conservation reserve, cotton, rice, and soybean uses, the chronic risk LOC is exceeded for dosebased estimates of small and/or medium sized mammals feeding on short grass. For the ornamentals and rightsof-way uses, the chronic risk LOC is exceeded for dose-based estimates of multiple size classes and dietary 

items.

6 This assessment also indicates that all labeled uses of FPE pose potential risks of concern to listed 

monocotyledonous (monocot) plants, which is supported by a series of incidents reported for grain crops treated 

with FPE

7 Although risks of concern were identified for listed aquatic vertebrates inhabiting 1 inch of rice paddy water, 

such a scenario is considered unlikely and therefore there are no expectations of direct effects to aquatic 

vertebrates from the labeled rice use.

5.3. Listed Species Occurrence Associated with FPE Uses

This screening-level risk assessment for FPE assumes that the pesticide may be applied 

nationwide, including throughout U.S. territories and possessions. Therefore, no federally listed 

species are excluded from the screening-level analyses, unless otherwise indicated (e.g., if only 

listed due to similarity of appearance to another listed species). Based on this screening-level 

assessment, there are potential risks from direct effects to listed mammals, freshwater fish, 

estuarine/marine invertebrates, and to monocot plants from the use of FPE on some of its registered 

use sites. Listed species of all plant and animal taxa may also be affected through indirect effects 

because of the potential direct effects on listed and non-listed species. Potential direct effects on 

listed mammals from the use of FPE may be associated with modification of Primary Constituent 

Elements (PCEs) of designated critical habitats, where such designations have been made. 

However, at this current stage of the Registration Review process, it is premature to make effects 

determinations for listed species until further scientific analysis and refinements are conducted, 

based on recommendations received from the National Academy of Sciences’ (NAS) National 

Research Council (NRC) April 2013 report, available at

http://www.nap.edu/catalog.php?record_id=18344. The NAS report outlines recommendations on 

specific scientific and technical issues related to the development of pesticide risk assessments that 

are compliant with the Endangered Species Act (ESA) and the Federal Insecticide, Fungicide, and 

Rodenticide Act (FIFRA).

The EPA along with the U.S. Fish & Wildlife Service (USFWS), the National Marine Fisheries 
-Page 76 of 116-

Service (NMFS) (collectively, the Services), and the U.S. Department of Agriculture (USDA), 

released a summary of their implementation plan for assessing risks of pesticides to listed species 

ahead of the stakeholder workshop held on November 15, 2013. This plan was developed in 

response to the NAS’ recommendations, including a common approach to risk assessment as a 

way of addressing scientific differences between EPA and the Services. During the workshop, the 

agencies received feedback from the public on the interim scientific approaches that were 

developed as part of the initial implementation of the NAS recommendations. These approaches 

will be jointly implemented and vetted as part of a phased iterative process. Once fully vetted, 

EPA will further refine the listed species effects determination portion of this risk assessment. 

To make effects determinations for individual listed species, useful refinements may include, but 

are not limited to, analyses of: 1) more detailed, species-specific ecological and biological data; 2) 

more detailed and accurate information on FPE use patterns; and 3) sub-county level spatial 

proximity data for the co-occurrence of potential effects areas and listed species and any designated 

critical habitat. Examples of such refinements are described below.

EFED is currently developing tools that are expected to further refine the assessment and are 

designed to support effects determinations for individual listed species and their designated critical 

habitats (where applicable). Scientific information obtained from the Services, and other reliable 

sources is being collated by EFED to address all currently listed species. This information is being

stored in an Office of Pesticide Programs (OPP) Pesticide Registration Information SysteM

(PRISM) listed species knowledgebase. The listed species knowledgebase consists of an 

information repository that houses biological and behavioral information relevant to individual 

species (e.g., habitat, diet, and life history, including specific temporal and spatial associations) 

and a document repository that contains supporting documents (e.g., USFWS recovery plans) and 

electronic information (e.g., GIS data files). For terrestrial taxa, biological information relevant 

to the assessment (e.g., diet and body weight) will be used to parameterize exposure estimates 

using a method consistent with currently used methods in the T-REX and T-HERPS models. 

Refinements will also include more detailed analyses of the registered uses and specific use 

patterns that result in either “Likely to Adversely Affect” (LAA) or “Not Likely to Adversely 

Affect” (NLAA) determinations for federally listed species. The analyses may include more 

information on where, when, and how FPE is used on all use sites. Actual usage data (when 

available) and national land-cover datasets that indicate potential use sites [e.g., National Land 

Cover Dataset (NLCD), Cropland Data Layer (CDL)] may be used to support a more refined 

analysis of where FPE is reasonably expected to be used. Similarly, refinements on the timing of 

applications and a more in-depth exploration of agronomic practices for FPE may be included as 

part of the refinement.

The refinements based on individual species data; additional, detailed usage information, when 

available; and recommendations from the NRC report are expected to help to more accurately 

identify potential areas of effect and to better inform effects and habitat determinations for listed 

species and any designated critical habitats.
-Page 77 of 116-

6. Endocrine Disruptor Screening Program

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential adverse 

outcomes from exposure to chemicals. Collectively, these studies include acute, subchronic and 

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, and 

sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic 

studies that assess growth, developmental and reproductive effects in different taxonomic groups. 

As part of its most recent registration decision for FPE, 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), FPE 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. 

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 

2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, 

which contains 58 pesticide active ingredients and 9 inert ingredients. A second list of chemicals 

identified for EDSP screening was published on June 14, 20134and includes some pesticides 

scheduled for registration review and chemicals found in water. Neither of these lists should be 

construed as a list of known or likely endocrine disruptors. 

FPE is on List 2. List 2 represents the next set of chemicals for which EPA intends to issue test 

orders/data call-ins in the near future. “For further information on the status of the EDSP, the 

policies and procedures, the lists of chemicals, future lists, the test guidelines and the Tier 1 

screening battery, please visit our website.5

7. References

American Bird Conservancy (ABC). 2007. Avian Incident Monitoring System. Available online at 

http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/simple.cfm.

 

4 See http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0477-0074 for the final second list of 

chemicals.

5 http://www.epa.gov/endo/
-Page 78 of 116-

Bayer CropScience. 2012. Letter from George Sabbagh, Ph.D., Registration Product Manager, Bayer 

CropScience to Molly Clayton, USEPA. Subject: Fenoxaprop-p-ethyl (FPE) – Registration No. 

264-653 and RR-129092-28665: Commitment to Revising Labels for Products containing FPE. 

November 30, 2012.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the EPA 

food-chain (Kenaga) nomogram, and instrument for estimating pesticide residues on plants. 

Environmental Toxicology and Chemistry 13 (9):1383-1391.

Hoerger, F., and E.E. Kenaga. 1972. Pesticide residues on plants: Correlation of representative data as a 

basis for estimation of their magnitude in the environment. In F. Coulston and F. Korte, eds., 

Environmental Quality and Safety: Chemistry, Toxicology, and Technology, Georg Thieme Publ, 

Stuttgart, West Germany, pp. 9-28.

Muller, T. A., & Kohler, H. P. (2004). Chirality of pollutants--effects on metabolism and fate. Appl 

Microbiol Biotechnol, Vol.64, No.3, pp.300-316

Kashuba, R., Spatz, D. 2006 Memorandum to Steven Bradbury, Subject: Standard Soil Mobility 

Classification Guidance 

Syngenta Crop Protection, Inc. 2012. Letter from Tamara Murphy, NAFTA Regulatory Product Manager 

to Molly Clayton, USEPA. Subject: Label Use Pattern Amendments-Fenoxaprop-p-ethyl FoxFire 

Herbicide (EPA Reg. No. 100-1429) and Fusion Herbicide (EPA Reg. No. 100-1059). November 

30, 2012.

Urban, D.J., and N. Cook. 1986. Ecological Risk Assessment. EPA 540/9–85-001. Office of Pesticide 

Programs. Washington, D.C.: U.S. Environmental Protection Agency. 

U.S. Environmental Protection Agency (USEPA). 2014. Fenoxaprop-p-ethyl. Registration Review 

Preliminary Risk Assessment and Proposed New Use on Grass Grown for Seed. (D403928 and 

D411289) Health Effects Division, Office of Pesticide Programs.

--2013a. Data on Fenoxaprop-p-ethyl and Its Environmental Transformation Products in Support of the 

ROCKS. DP Barcode 411291. September 25, 2013.

--2013b. T-REX Version 1.5 (Terrestrial Residue EXposure model). June 6, 2013.

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

--2012. BEAD. 2012. Screening Level Usage Analysis for Fenoxaprop and Fenoxaprop-p-ethyl, July 27, 

2012.

--2012. PRZM-GW: Guidance for Using PRZM-GW in Drinking Water Exposure Assessments (10/15/ 

2012)

--2011 AgDRIFT User’s Guide, December 29, 2011

--2010 STIR Version 1.0 (Screening Tool for Inhalation Risk) 

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

--2010 Version 1.0 (Screening Imbibition Program) http://www.epa.gov/oppefed1/models/terrestrial/
-Page 79 of 116-

--2009a. Pesticides; Data Requirements for Conventional Chemicals, Technical Amendments, and Data 

Requirements for Biochemical and Microbial Pesticides; Final Rule. FR 72(207):60933-60988.

--2009b. Water models. Available online at http://www.epa.gov/oppefed1/models/water/.

--2009c. ECOTOXicology Database, v. 4.0. Accessed on 16 November 2009. Available online at 

http://cfpub.epa.gov/ecotox/.

--2009d. Ecological Incident Information System, v. 2.1 . Accessed on 13 October 2009. Description

online at http://www.epa.gov/pesticides/science/models_db.htm.

--2009e. Guidance for Selecting Input Parameters in Modeling the Environmental Fate and Transport of 

Pesticides, Version 2.1. U.S. Environmental Protection Agency, Office of Prevention, Pesticides 

and Toxic Substances, Office of Pesticide Programs, Environmental Fate and Effects Division, 

October 22, 2009. Online at: 

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

--2009f. The FIFRA Scientific Advisory Panel. 2009. Minutes for the SAP Meeting on selected issues 

associated with risk assessment process for pesticides with persistent, bio-accumulative and toxic 

characteristics. October 28-31, 2008. Arlington, VA. (Document No. 2009-01 dated Jan 29, 

2009). http://www.epa.gov/scipoly/sap/meetings/2008/102808_mtg.htm

--2008. Science Advisory Panel (SAP): Selected Issues Associated with the Risk Assessment Process for 

Pesticides with Persistent, Bioaccumulative, and Toxic Characteristics. Office of Prevention, 

Pesticides and Toxic Substances, Office of Pesticide Programs, Washington, D.C. 

--2007a. Registration Review – Preliminary Problem Formulation for the Ecological Risk Assessment of 

Fenoxaprop-p-ethyl. July 12, 2007

--2007b. Guidance for Tier I Estimation of Aqueous Pesticide Concentrations in Rice Paddies (5/8/2007)

--2006a. PRZM User’s Manual. Online at: http://www.epa.gov/ceampubl/gwater/przm3/index.html

--2006b, TERRPLANT v. 1.2.2 User’s Guide. Office of Pesticide Programs, Environmental Fate and 

Effects Division, Washington, D.C. December 26, 2006.

--2005. EXAMS User’s Manual. Online at: http://www.epa.gov/ceampubl/swater/exams/index.html

--2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. 

Environmental Protection Agency. Endangered and Threatened Species Effects Determinations. 

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

Washington, D.C. Available online at 

http://www.epa.gov/oppfead1/endanger/consultation/ecorisk-overview.pdf.

--2003. SCIGROW: User’s Manual. Online at: http://www.epa.gov/oppefed1/models/water/#scigrow

--1998. Guidelines for Ecological Risk Assessment. EPA/630/R-95/002F. Published in 63 FR 26846; 

May 14, 1998. U.S. Environmental Protection Agency, Washington, DC. April, 1998.
-Page 80 of 116-

--1993. Wildlife Exposure Factors Handbook. EPA/600/R-13/187a. Office of Research and 

Development, Washington, D.C.

Willis, G.H. and L.L. McDowell. 1987. Pesticide persistence on foliage. Reviews of Environmental 

Contamination and Toxicology 100: 23-73.

7.1. Submitted Product Chemistry and Environmental Fate Studies

Acc. # 412-03-0113. Moraski, R. 1983. EAB Review of 8340 – EUP – T. HED memorandum, Nov. 3, 

1983. HED Records Center Series 361 Science Reviews – File R038903. 52 p.

MRID 41567707

Wink, O., Fischer, R. (1987) HOE 046360-14C Flow-through Bioaccumulation and Metabolism Study 

with Bluegill Subfish (Lepomis macrochirus): Lab Project Number: CM010/87 & Lm27/a. Report No. 

A37432. Unpublished study prepared by Hoechst AG. 84p.

MRID 42915001

Reynolds, J. (1993) Adsorption and Desorption of (Carbon 14)-Fenoxaprop-p-Ethyl in Four Soils: 

Replacement Report: Lab Project Number: XBL 91063: RPT0099. Unpublished study prepared by 

XenoBiotic Labs, Inc. 144 p.

MRID 43066404

Carringer, R.; O'Grodnick, J. (1993) Aquatic Dissipation of HOE 46360 75EW (Whip 360 Herbicide) 

(Fenoxaprop-p-ethyl) Applied to Rice in California: Final Report: Lab Project Number: 91-0028: 91-0016 

HOE AASI: 91-0016. Unpublished study prepared by American Agricultural Services, Inc. and EN-CAS 

Analytical Labs. 300 p.

MRID 44659601

Schollmeier, M.; Eyrich, U.; Uhl, A. (1992) HOE 0463060, (Fenoxaprop-p-Ethyl); Determination of the 

Partition Coefficient n-Octanol/Water (HOE 046360 00 ZB98 0001): Lab Project Number: CP92/131: 

A49082. Unpublished study prepared by Hoechst AG. 22 p.

MRID 44676401

Schwab, W. (1993) HOE 046360-(carbon-14), Photodegradation of Fenoxaprop-p-ethyl in Surface Water, 

Sterile Buffer and Distilled Water: Lab Project Number: A51353: CP91/035. Unpublished study prepared 

by Hoechst Aktiengesellschaft. 151 p.

MRID 45081601

Volkel, W. (2000) (carbon-14)-AE F046360/(carbon-14)-AE F033171: Degradation and Metabolism in 

an Anaerobic Aquatic System: Lab Project Number: 725040: C007381. Unpublished study prepared by 

RCC Ltd. 114 p.

MRID 45081602

Tarara, G. (2000) (U-(carbon-14)-Chlorophenyl)AE F046360: Degradation in Two Sediment/WaterSystems at 20(degrees)C Under Aerobic Conditions: Lab Project Number: CB98/113: C007688. 

Unpublished study prepared by Hoechst Schering AgrEvo GmbH. 167 p.

MRID 47123201

Van Der Gaauw, A. (2002) (Carbon 14)-Fenozaprop-Ethyl: Hydrolysis at Five Different pH Values: AE 

F046360. Project Number: 815670, C/028353. Unpublished study prepared by RCC Ltd. 71 p.
-Page 81 of 116-

MRID 47123208

Fitzmaurice, M. (2004) [Carbon 14]-Fenoxaprop-P-Ethyl: Degradation and Retention in Two 

Water/Sediment Systems. Project Number: C046009, MEFPX011, CX/04/045. Unpublished study 

prepared by Battelle AgriFood, Ltd. 123 p.

MRID 48098502

Fitzmaurice, M. (2008) [Carbon 14]-Fenoxaprop-P-Ethyl: Aqueous Photolysis in Sterile Buffer Solution 

at pH 7. Project Number: CX/05/031, M/344639/01/1, MEF/06/335. Unpublished study prepared by 

Battelle Agrifood, Ltd. 132 p.

MRID 48757101

Shepherd, J. (2012) [Chlorophenyl-UL-(Carbon 14)]Fenoxaprop-P-Ethyl: Aerobic Soil Metabolism in 

Four US Soils. Project Number: MEFPL006, MEFPL006/1, M/424708/02/1. Unpublished study 

prepared by Bayer CropScience. 171p.

MRID 48868703

Shepherd, J.; Ripperger, R. (2012) (Phenoxy-UL-Carbon 14) Fenoxaprop-P-ethyl: Aerobic Soil 

Metabolism in Four U.S. Soils: Amended Report. Project Number: MEFPL009, M/424988/02/1. 

Unpublished study prepared by Bayer CropScience. 181p.

MRID 48868701

Xu, T. (2012) (Phenoxy-UL-Carbon 14) and (Chlorophenyl-UL-Carbon 14) Fenoxaprop-p-ethyl: Aerobic 

Aquatic Metabolism in Two Sediment/Water Systems. Project Number: MEFPL007, M/431724/01/1. 

Unpublished study prepared by Bayer CropScience and Agvise Laboratories, Inc. 168p.

MRID 48868702

Ripperger, R. (2012) (Chlorophenyl-UL-Carbon 14) and (Phenoxy-UL-Carbon 14) Fenoxaprop-P-Ethyl: 

Anaerobic Aquatic Metabolism in Two Water/Sediment/Systems. Project Number: MEFPL007, 

M/431724/01/1. Unpublished study prepared by Bayer CropScience. 171p.

7.2. Submitted Ecotoxicity Studies

MRID 43972209

Ebert, E.; Leist, K. (1991) (Inert Ingredient): Testing for Acute Oral Toxicity in the Male and Female 

Mallard Duck (Anas platyrhynchos): Lab Project Number: A45650: 90.0992. Unpublished study prepared 

by Hoechst Aktiengesellschaft. 32 p. 

MRID 44739126

Ebert, E. (1998) (Inert Ingredient) Code: CR 21492/03: Bobwhite Quail Acute Oral Toxicity Study: Lab 

Project Number: 96.0766: A59889: T/020/96. Unpublished study prepared by Hoechst Marion Roussel. 

29 p. {OPPTS 850.2100} 

MRID 44739127

Ebert, E. (1998) (Inert Ingredient) Code: CR 21492/03: Mallard Duck Acute Oral Toxicity Study: Lab 

Project Number: 96.0767: A59890: T/020/96. Unpublished study prepared by Hoechst Marion Roussel. 

29 p. {OPPTS 850.2100} 
-Page 82 of 116-

MRID 47333401

Ebert, E.; Leist, K. (1986) Testing for Acute Oral Toxicity in the Male and Female Japanese Quail 

(Coturnix coturnix japonica): HOE 046360. Project Number: 85/0792, A36978, 87/1323. Unpublished 

study prepared by Pharmakologishes Inst. der Rheinischen Friedrich- Wilhelms-.24 p.

MRID 47333402

Ebert, E.; Leist, K. (1986) Testing for Acute Oral Toxicity in the Male and Female Mallard Duck (Anas 

platyrhynchos): HOE 046360. Project Number: 85/0790, A36428, 86/0168. Unpublished study prepared 

by Pharmakologishes Inst. der Rheinischen Friedrich- Wilhelms-. 24 p.

MRID 47333403

Ebert, E.; Leist, K. (1986) Testing for Acute Oral Toxicity in the Male and Female Bobwhite Quail 

(Colinus virginianus). Project Number: 85/0791, 86/0169, A36429. Unpublished study prepared by 

Pharmakologishes Inst. der Rheinischen Friedrich- Wilhelms-. 24 p.

MRID 47333404

Ebert, E.; Leist, K. (1986) Testing for Acute Oral Toxicity in the Male and Female Partridge (Perdix 

perdix): HOE 046360. Project Number: 85/0793, 86/0261, A36679. Unpublished study prepared by 

Pharmakologishes Inst. der Rheinischen Friedrich- Wilhelms-. 22 p.

MRID 43972210

Ebert, E. (1992) (Inert ingredient): 8-Day Dietary LC50 Test in the Mallard Duck (Anas platyrhynchos): 

Lab Project Number: 92.0449: BE0083: A49551. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 44 p. 

MRID 44739128

Ebert, E. (1998) (Inert Ingredients) Mallard Duck LC50 Study: Lab Project Number: 96.0783: A59887: 

T/021/97. Unpublished study prepared by Hoechst Marion Roussel. 32 p. {OPPTS 850.2200} 

MRID 44739129

Ebert, E. (1998) (Inert Ingredients) Bobwhite Quail LC50 Study: Lab Project Number: 96.0782: A67552: 

97.0729. Unpublished study prepared by Hoechst Marion Roussel. 31 p. {OPPTS 850.2200}

MRID 47333405 

Ebert, E.; Leist, K. (1986) 8-Day Dietary LC50 Test in the Japanese Quail (Coturnix coturnix japonica): 

HOE 046360. Project Number: 85/0796, 86/0401, A36733. Unpublished study prepared by 

Pharmakologishes Inst. der Rheinischen Friedrich- Wilhelms-. 26 p.

MRID 47333406

Ebert, E.; Roberts, N.; Phillips, C. (1986) The Dietary Toxicity (LC50) of HOE 046360- Substance 

Technical (Code 046360 OH ZC96 0002) to the Bobwhite Quail. Project Number: A34917, 

HST/297/86976. Unpublished study prepared by Pharmakologishes Inst. der Rheinischen FriedrichWilhelms- and Huntingdon Life Sciences, Ltd. 21 p.

MRID 47333407

Ebert, E.; Leist, K. (1986) 8-Day Dietary LC50 Test in the Mallard Duck (Anas platyrhynchos): HOE 

046360. Project Number: A36430, 86/0579, 85/0794. Unpublished study prepared by Pharmakologishes 

Inst. der Rheinischen Friedrich- Wilhelms-. 26 p.

MRID 47333408
-Page 83 of 116-

Schnurstein, A. (2002) Bobwhite Quail Dietary Reproduction Study: Fenoxaprop-P-ethyl. Project 

Number: C027500, PT01/0109, NG/28022. Unpublished study prepared by Aventis Pharma Deutschland 

Gmbh. 154 p.

MRID 43972207

Heusel, R. (1991) (Inert Ingredient): Effect to Oncorhynchus mykiss (Rainbow Trout) in a Static-Acute 

Toxicity Test (Method OECD): Lab Project Number: CE91/050: A47038. Unpublished study prepared by 

Hoechst Aktiengesellschaft. 32 p. 

MRID 44739130

Stachura, B.; Ruff, D. (1997) (Inert Ingredients): The 96 Hour Acute Toxicity to the Rainbow Trout, 

Oncorhynchus mykiss, in a Flow Through System: Lab Project Number: 505CA: A57757: CA97T505. 

Unpublished study prepared by AgrEvo USA Company. 52 p. {OPPTS 850.1075} 

MRID 44739131

Stachura, B.; Ruff, D. (1997) (Inert Ingredient) 98.0% w/w Code: AE F122006 00 1C99 0002: The 96 

Hour Acute Toxicity to the Bluegill Sunfish, Lepomis macrochirus, in a Flow Through System: Lab 

Project Number: CA98W504: A67510: C/085/97. Unpublished study prepared by AgrEvo USA 

Company. 56 p. {OPPTS_850.1075} 

MRID 44801502

Stachura, B.; Ruff, D. (1999) Fenoxaprop-p-ethyl Technical: 88.1% w/w: Code: AE F046360 00 1C97 

0002: The 96 Hour Chronic Toxicity to the Bluegill Sunfish Lepomis macrochirus, in a Flow-Through 

System: Lab Project Number: BM98W521: C002415. Unpublished study prepared by AgrEvo Research 

Center. 53 p. 

MRID 44801503

Stachura, B.; Ruff, D. (1999) AE F054014 Technical: 99.7% w/w: Code: AE F054014 00 1C99 0004: 

The 96 Hour Acute Toxicity to the Rainbow Trout, Oncorhynchus mykiss, in a Static Renewal System: 

Lab Project Number: BM98W522: C002416. Unpublished study prepared by AgrEvo Research Center. 

41 p. 

MRID 44801504

Stachura, B.; Ruff, D. (1999) Fenoxaprop-p-ethyl Technical: 88.1% w/w: Code: AE F046360 00 1C97 

0002: The 96 Hour Acute Toxicity to the Rainbow Trout, Oncorhynchus mykiss, in a Flow-Through 

System: Lab Project Number: BM98W520: C002145. Unpublished study prepared by AgrEvo Research 

Center. 52 p. 

MRID 47333413

Heusel, R. (1996) Acute Toxicity to Rainbow Trout (Oncorhynchus mykiss): Fenoxaprop-P. Project 

Number: CE96/122, A57595. Unpublished study prepared by Hoechst Aktiengesellschaft. 35 p.

MRID 47333418

Schafers, C. (2004) Rainbow Trout (Oncorhynchus mykiss), Acute Toxicity Test (OECD 203), Semistatic Exposure: AE F06918: Final Report. Project Number: BAY/021/4/12. Unpublished study prepared 

by Fraunhofer Institute for Molecular Biology and Applied Ecology. 27 p.

MRID 47333428

Heusel, R. (1996) Feoxaprop-P-ethyl + (Inert Ingredient): Effect to Oncorhynchus myskiss (Rainbow 

Trout) in a 96 Hours Static Acute Toxicity Test. Project Number: CE95/042, A56435. Unpublished study 

prepared by Hoechst Aktiengesellschaft. 38 p.
-Page 84 of 116-

MRID 47333431

Heusel, R. (1996) Fenoxaprop-P-ethyl + (Inert Ingredient) Emulsifiable Concentrate 120 + 33g/L: Acute 

Toxicity to Bluegill Sunfish (Lepomis macrochirus). Project Number: CE95/043, A56692. Unpublished 

study prepared by Hoechst Aktiengesellschaft. 38 p.

MRID 48492501

Bomke, C. (2011) Acute Toxicity of Fenoxaprop-P-Ethyl to Fish (Pimephales promelas) Under FlowThrough Conditions. Project Number: EBFPL012, E/280/3970/9, M/407842/01/1. Unpublished study 

prepared by Bayer CropScience. 75 p.

MRID 43972208

Heusel, R. (1991) (Inert Ingredient): Effect to Daphnia magna (Waterflea) in a Static-Acute Toxicity Test 

(Method OECD): Lab Project Number: CE91/048: A46758. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 23 p. Relates to letter L0000216. 

MRID 44664002

Stachura, B.; Ruff, D. (1998) Fenoxaprop-p-ethyl Technical 88.1% w/w: Code: AE F046360 00 1C97 

0002: The 48 Hour Acute Toxicity to Daphnia magna, in a Static Renewal System: Lab Project Number: 

BMM98W514: A67511: AZ 06135. Unpublished study prepared by AgrEvo USA Company. 48 p. 

MRID 44739132

Stachura, B.; Ruff, D. (1997) (Inert Ingredients): The 96 Hour Acute Toxicity to Daphnia magna in a 

Flow Through System: Lab Project Number: 506CA: A57758: CA97T506. Unpublished study prepared 

by AgrEvo USA Company. 44 p. {OPPTS 850.1010} 

MRID 44801505

Young, B.; Ruff, D. (1999) AE F054014 Technical: 99.7% w/w: Code: AE F054014 00 1C99 0004: The 

48 Hour Acute Toxicity to the Water Flea, Daphnia magna, in a Static Renewal System: Lab Project 

Number: BM98W524: C002434. Unpublished study prepared by AgrEvo Research Center. 44 p. 

MRID 47333415

Heusel, R. (1993) Fenoxaprop-P: Effect to Daphnia magna (Waterflea) in a Static-Acute Toxicity Test 

(Method OECD). Project Number: CE92/002, A50393. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 34 p.

MRID 47333420

Schaefers, C. (2004) Daphnia magna, Acute Immobilization Test (OECD 202): Final Report. Project 

Number: BAY/021/4/20, C043957. Unpublished study prepared by Fraunhofer Institute for Molecular 

Biology and Applied Ecology. 25 p.

MRID 47333429

Heusel, R. (1996) Fenoxaprop-P-ethyl + (Inert Ingredient): Effect to Daphnia magna (Waterflea) in a 48 h 

Static Acute Toxicity Test. Project Number: CE95/041, A56436. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 41 p.

MRID 41276902

Burgess, D. (1989) Acute Toxicity of HOE-046360 to Mysidopsis bahia: Lab Project Number: 37525. 

Unpublished study prepared by ABC Laboratories, Inc. 214 p. 
-Page 85 of 116-

MRID 44786801

Stachura, B.; Ruff, D. (1999) Fenoxaprop-p-ethyl Technical: Effects on Early Life Stages of Rainbow 

Trout, Oncorhynchus mykiss: Lab Project Number: BM98W513: C002144. Unpublished study prepared 

by AgrEvo Research Center. 168 p. 

MRID 44786802

Boeri, R.; Magazu, J.; Ward, T. (1999) Fenoxaprop-p-ethyl Technical: The 28 Day Chronic Toxicity to 

the Mysid, Mysidopsis bahia in a Flow Through System: Lab Project Number: C002140: 1656-AG: 

BM98W519. Unpublished study prepared by T.R. Wilbury Laboratories, Inc. 85 p. 

MRID 48417901

Bomke, C. (2011) Early-Life Stage Toxicity of Fenoxaprop-p-ethyl (Techn.) to Fish (Pimephales 

promelas). Project Number: EBFPL009, E/284/3971/4, M/403248/01/1. Unpublished study prepared by 

Bayer CropScience. 102 p.

MRID 47332701

Bruns, E. (2006) Fenoxaprop-P-Ethyl & Mefenpyr-Diethyl; Oil in Water Emulsion; 69+75 g/l Daphnia 

magna Chronic Toxicity Test, Dosed at Two Life Stages in an Uncovered Static Laboratory Test System. 

Project Number: E3213021/2, EBFPX008, AEF04636024EW14A717. Unpublished study prepared by 

Bayer Ag, Institute of Product Info. & Residue Anal. 94 p.

MRID 47332702

Schaefers, C. (2002) Daphnia magna, Reproduction Test, Dosed at Two Life Stages Part B: Reproduction 

Test Fenoxaprop-P-ethyl + Mefenpyr-diethyl; Oil in Water Emulsion, 69 + 75 g/L. Project Number: 

C027503, AEF04636024EW14A716, ACS/004/4/21. Unpublished study prepared by Fraunhofer Institute 

for Molecular Biology and Applied Ecology. 85 p.

MRID 47332703

Heusel, R. (1994) Fenoxaprop-P-ethyl - Oil in Water Emulsion 69 g/L Code: Hoe 046360 24 EW14 A703 

Effect to Daphnia magna (Waterflea) in a 21-day Reproduction Test (Method OECD). Project Number: 

A53038, CE94/006. Unpublished study prepared by Hoechst Schering Agrevo Gmbh. 157 p.

MRID 47332704

Fischer, R. (1989) The Effect of Fenoxaprop-P-ethyl - Oil in Water Emulsion (Identification Code: Hoe 

046360 OH EW07 A209 to Daphnia magna (Waterflea) in a 21-Day Reproduction Test (Method OECD). 

Project Number: 89/CEO43, A41741. Unpublished study prepared by Hoechst Aktiengesellschaft. 112 p.

MRID 47332705

Fischer, R. (1989) The Effect of Fenoxaprop-ethyl - Substance, Technical (Identitication Code: Hoe 

033171 OH ZD98 0001) to Daphnia magna (Waterflea) in a 21-Day Reproduction Test (Method OECD) . 

Project Number: CE89/042/3, A41480, CE89J042. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 110 p.

MRID 47332706

Fischer, R. (1989) The Effect of Fenoxaprop-P-ethyl - Substance, Technical (Identification Code: Hoe 

046360 OH ZC97 0002) to Daphnia magna (Waterflea) in a 21-Day Reproduction Test (Method OECD). 

Project Number: CE033/89, A41697, CE89/033. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 113 p.

MRID 47333416
-Page 86 of 116-

Ebeling, M.; Nguyen, D.; Gosch, H. (2002) Fenoxaprop-P: Daphnia magna Chronic Toxicity and 

Reproduction Test Under Semi-static Conditions. Project Number: CE02/057, C026337. Unpublished 

study prepared by Bayer Cropscience Gmbh. 63 p.

MRID 47333421

Schaefers, C. (2004) Daphnia magna, Reproduction test (OECD 211) Semi-static Exposure: AE F096918: 

Final Report. Project Number: C045676, BAY/021/4/21. Unpublished study prepared by Fraunhofer 

Institute for Molecular Biology and Applied Ecology. 42 p.

MRID 47333414

Sowig, P.; Gosch, H. (2003) Effects on Juvenile Growth of Oncorhynchus mykiss (Rainbow Trout) in a 

28 Days Flow-Through Study: Fenoxaprop-P; Substance, Technical. Project Number: CE02/058, 

C027516. Unpublished study prepared by Bayer Cropscience Gmbh. 47 p. . NOT A FIFRA Guideline

MRID 47333419

Schaefers, C. (2004) Rainbow trout (Oncorhynchus mykiss), Juvenile Growth Test (OECD 215), Flow 

Trough Conditions: Final Repor. Project Number: BAY/021/4/63, C045675. Unpublished study prepared 

by Fraunhofer Institute for Molecular Biology and Applied Ecology. 41 p. NOT A FIFRA Guideline

MRID 48417901

Bomke, C. (2011) Early-Life Stage Toxicity of Fenoxaprop-p-ethyl (Techn.) to Fish (Pimephales 

promelas). Project Number: EBFPL009, E/284/3971/4, M/403248/01/1. Unpublished study prepared by 

Bayer CropScience. 102 p.

MRID 47333412

Meyer, B.; Young, B. (1999) Bioaccumulation and Metabolism of (carbon-14)-Chlorophenyl AE 

F046360 in Bluegill Sunfish, Lepomis macrochirus, in a Flow-Through System. Project Number: 

A500/CE0026, BM98E517, C002136. Unpublished study prepared by Agrevo USA Co. 118 p.

MRID 41276904

Chetram, R. (1989) Tier 1: Seed Germination/Seedling Emergence: Nontarget Phytotoxicity Study: HOE046360: Lab Project Number: LR88/110B. Unpublished study prepared by Pan-Agricultural Laboratories, 

Inc. 155 p. 

MRID 41276906

Chetram, R. (1989) Tier 1: Vegetative Vigor Nontarget Phytotoxicity Study: HOE-046360: Lab Project 

Number: LR88/110A. Unpublished study prepared by Pan-Agricultural Laboratories, Inc. 124 p. 

MRID 47333423

Roshon, R. (2001) Ecotoxicological Evaluation of Fenoxaprop-P-Ethyl+(Inert Ingredient) Emulsifiable 

Concentrate (120 + 30 g/L) (PUMA 120 Speed), Terrestrial Plant Seedling Emergence: Final Report. 

Project Number: 1230, SO497, B003326. Unpublished study prepared by ESG International, Inc. 305 p.

MRID 47333424

Roshon, R. (2001) Ecotoxicological Evaluation of Fenoxaprop-P-Ethyl + (Inert Ingredient) Emulsifiable 

Concentration (120+33 g/L) (PUMA 120 SUPER), Terrestrial Plant Vegetative Vigour: Final Report. 

Project Number: B003327, S0497, 1230. Unpublished study prepared by ESG International, Inc. 551 p.

MRID 41276907

Chetram, R. (1989) Tier 2: Vegetative Vigor Nontarget Phytotoxicity Study: HOE-046360: Lab Project 

Number: LR89/14A. Unpublished study prepared by Pan-Agricultural Laboratories, Inc. 13 p. 
-Page 87 of 116-

MRID 41276903

Fischer, R. (1989) The Effect of HOE-046360 - Oil in Water Emulsion (Identification Code: HOE046360 OH EW07 A209) to Selenastrum capricornutum (Green Alga) in an Algal Assay Bottle Test 

(Method EPA): Lab Project Number: SC5. Unpublished study prepared by Hoechst AG 29 p. 

MRID 41276905

Chetram, R. (1989) Tier 2: Seed Germination/Seedling Emergence Nontarget Phytotoxicity Study: HOE046360: Lab Project Number: LR89/14B. Unpublished study prepared by Pan-Agricultural Laboratories, 

Inc. 134 p. 

MRID 44739133

Christ, M.; Ruff, D. (1998) (Inert Ingredient) Effect to Pseudokircheriella Subcapitata (Green Alga) in a 

Growth Inhibition Test: Lab Project Number: CA97W508: A57881: T/010/97. Unpublished study 

prepared by AgrEvo USA Company. 53 p. {OPPTS 870.5400} 

MRID 44768103

Christ, M.; Ruff, D. (1999) Fenoxaprop-P-ethyl Technical 88.1% w/w: Effect to Anabaena flos-aquae 

(Blue-Green Alga) in a Growth Inhibition Test: Lab Project Number: BM98W518: C000918: BM518. 

Unpublished study prepared by AgrEvo Research Center. 60 p. 

MRID 44768104

Young, B.; Ruff, D. (1999) Fenoxaprop-P-ethyl Technical 88.1% w/w: Effect to Skeletonema costatum 

(Marine Diatom) in a Growth Inhibition Test: Lab Project Number: BM98W516: C000916: BM/01/97. 

Unpublished study prepared by AgrEvo Research Center. 53 p. 

MRID 44801501 

Christ, M.; Ruff, D. (1999) AE F054014 Technical: 99.7% w/w: Code: AE F054014 00 1C99 0004: 

Effect to Pseudokirchneriella subcapitata (Green Alga) in a Growth Inhibition Test: Lab Project Number: 

BM98W523: C002718. Unpublished study prepared by AgrEvo Research Center. 105 p. 

MRID 44664003

Christ, M.; Ruff, D. (1997) Fenoxaprop-p-ethyl Technical 88.1% w/w: Code: AE F046360 00 1C97 0002: 

The Toxicity to Duckweed (Lemna gibba), in a Static Renewal System: Lab Project Number: BM9W502: 

A57845: AZ 07051. Unpublished study prepared by AgrEvo USA Company. 56 p. 

MRID 44768105

Sowig, P.; Weller, O.; Gosch, H. (1999) Algal Growth InhibitionNavicula pelliculosa: Fenoxaprop-Pethyl Substance, Technical: Lab Project Number: CE98/107: C001890: CE98/107-2. npublished study 

prepared by Hoechst Schering AgrEvo GmbH. 41 p. 

MRID 47333425

Roshon, R. (2001) Ecotoxicological Evaluation of Fenoxaprop-P-Ethyl+ (Inert Ingredient) Emulsifiable 

Concentrate (120 + 33 g/L) (PUMA 120 SUPER), Aquatic Plant (Lemna Gibba) Toxicity: Final Report. 

Project Number: S0497, B003328, 1230. Unpublished study prepared by ESG International, Inc.. 150 p.

MRID 47333417

Heusel, R. (1993) Fenoxaprop-P: Effect to Selenastrum capricornutum (Green alga) in an Algal Assay 

Bottle Test (Method EPA). Project Number: CE92/003, A50170. Unpublished study prepared by Hoechst 

Aktiengesellschaft. 70 p.

MRID 47333422
-Page 88 of 116-

Ebert, E. (2004) Alga, (Pseudokirchneriella subcapitata), Growth Inhibition Test (OECD 201), Static 

Exposure: AE F096918: Final Report. Project Number: BAY/021/4/30, C043958. Unpublished study 

prepared by Fraunhofer Institute for Molecular Biology and Applied Ecology. 50 p.

MRID 47333426

Dorgerloh, M. (2005) Pseudokirchneriella subcapitata (formerly named Selenastrum capricornutum)-

Growth Inhibition Test with Fenoxaprop-P-ethyl & (Inert Ingredient) Emulsifiable concentrate 120 +33 

g/L. Project Number: M/253287/01/1. Unpublished study prepared by Bayer Cropscience Gmbh. 74 p.

MRID 47333427

Heusel, R. (1996) Fenoxaprop-P-ethyl + (Inert Ingredient) Effect to the Green Alga Selenastrum 

capricornutum in a 120 Hours Growth Inhibition Test. Project Number: CE95/045, A56200. Unpublished 

study prepared by Hoechst Aktiengesellschaft. 47 p.

MRID 48566201

Banman, C.; Howerton, J.; Lam, C. (2011) Toxicity of Fenoxaprop-P-ethyl Technical to Freshwater 

Diatom Navicula pelliculos. Project Number: EBFPL011, M/411456/01/1. Unpublished study prepared 

by Bayer CropScience. 65p.

MRID 47333411

Winkler, J. (2000) Toxicity to the HoneyBee Apis mellifera L. (laboratory):(Fenoxaprop-P-ethyl). Project 

Number: 99/1048/100, 46360/00/1D96/0001. Unpublished study prepared by: Biochem Agrar, Labor fuer 

Biologische und Chemische Analytik and Hoechst Aktiengesellschaft. 20 p.

MRID 47333430

Waltersdorfer, A. (1996) Contact Toxicity (LD50) to Honey Bees (Apis mellifera L.). Project Number: 

CW/95/078. Unpublished study prepared by Hoechst Aktiengesellschaft. 15 p.

MRID 47333432

Waltersdorfer, A. (1996) Oral Toxicity (LD 50) to Honey Bees (Apis mellifera L.). Project Number: 

CW/95/079. Unpublished study prepared by Hoechst Aktiengesellschaft. 14 p.

MRID 47333410

Memmert, U. (2000) Effects of Fenoxaprop-P-ethyl, Substance Technical; Code AE F046360 on the 

Development of Sediment- Dwelling Larvae of Chironomus riparius in a Water-Sediment System. Project 

Number: 732194, C006993. Unpublished study prepared by RCC Umweltchemie Ag. 66 p.
-Page 89 of 116-

Appendix A. Chemical Names and Structures of FPE and its Degradates

Chemical Structure

Fenoxaprop-p-ethyl

(+)-ethyl 2-[4-[(6-chloro-2-

benzoxazolyl)oxy]phenoxy]propanoate

AE F046360

Fenoxaprop-p

((D+)-2-[4-(6-chloro-2-

benzoxazolyloxy) phenoxy] propanoate

AE F088406

Chlorobenzoxazolone

4-(6-chloro-2-benzoxazolyloxy) phenol

AE F054014

4-(6-chloro-2-

benzoxazolyloxy)phenol

AE F040356

O

O

O

O

N

O

Cl OH

O

O

O

N

O

Cl NH

O

Cl

O

OH

O

N

O

Cl
-Page 90 of 116-

Appendix B. PRZM/EXAMS Sample Input/Output Data

Barley/Wheat

stored as fpe_tx_wheat.out

Chemical: fpe

PRZM environment: TXwheatOP.txt modified Thuday, 14 June 2007 at 11:24:44

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 13:47:26

Metfile: w13958.dvf modified Wedday, 3 July 2002 at 10:06:24

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 1.747 0.3024 0.05769 0.02019 0.01346 0.004765

1962 0.7374 0.126 0.0241 0.008434 0.005623 0.002672

1963 0.8113 0.1304 0.02488 0.008708 0.005805 0.00266

1964 0.7374 0.1702 0.0356 0.01246 0.008308 0.00338

1965 0.7374 0.1413 0.02746 0.009639 0.006426 0.002954

1966 0.7374 0.1313 0.0252 0.008819 0.005879 0.002836

1967 0.7374 0.1346 0.02633 0.009223 0.006148 0.002792

1968 0.7374 0.128 0.02478 0.008675 0.005783 0.002762

1969 0.7374 0.1321 0.02537 0.008949 0.005966 0.002853

1970 0.7374 0.1754 0.03397 0.01189 0.007927 0.003331

1971 0.7374 0.1306 0.02522 0.008828 0.005886 0.002785

1972 0.7374 0.124 0.02377 0.008328 0.005552 0.002694

1973 0.7374 0.1318 0.02532 0.008863 0.005909 0.002838

1974 0.7374 0.136 0.02621 0.009175 0.006117 0.002872

1975 0.7374 0.1611 0.03139 0.01099 0.007328 0.003229

1976 0.7374 0.166 0.03325 0.01164 0.00776 0.003312

1977 0.7374 0.1211 0.02322 0.008127 0.005418 0.002668

1978 0.7374 0.1291 0.02544 0.008904 0.005936 0.002772

1979 0.7374 0.1256 0.02394 0.008379 0.005586 0.002711

1980 0.7374 0.1322 0.02537 0.009133 0.006089 0.002743

1981 0.7374 0.124 0.02364 0.008274 0.005516 0.002686

1982 0.7374 0.1241 0.02386 0.008368 0.005579 0.002708

1983 0.7374 0.129 0.02469 0.00864 0.00576 0.002752

1984 0.7374 0.1275 0.02443 0.008562 0.005708 0.002698

1985 0.7374 0.1236 0.02728 0.009547 0.006365 0.002911

1986 0.818 0.1869 0.03591 0.01257 0.008383 0.003401

1987 0.7635 0.1298 0.02504 0.008763 0.005842 0.002863

1988 0.7374 0.1238 0.02364 0.008273 0.005515 0.002667

1989 0.7374 0.1218 0.02332 0.008167 0.005445 0.002679

1990 0.7374 0.1279 0.02451 0.00858 0.00572 0.00263

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 1.747 0.3024 0.05769 0.02019 0.01346 0.004765

0.0645161290322581 0.818 0.1869 0.03591 0.01257 0.008383 0.003401

0.0967741935483871 0.8113 0.1754 0.0356 0.01246 0.008308 0.00338

0.129032258064516 0.7635 0.1702 0.03397 0.01189 0.007927 0.003331

0.161290322580645 0.7374 0.166 0.03325 0.01164 0.00776 0.003312

0.193548387096774 0.7374 0.1611 0.03139 0.01099 0.007328 0.003229

0.225806451612903 0.7374 0.1413 0.02746 0.009639 0.006426 0.002954

0.258064516129032 0.7374 0.136 0.02728 0.009547 0.006365 0.002911

0.290322580645161 0.7374 0.1346 0.02633 0.009223 0.006148 0.002872

0.32258064516129 0.7374 0.1322 0.02621 0.009175 0.006117 0.002863
-Page 91 of 116-

0.354838709677419 0.7374 0.1321 0.02544 0.009133 0.006089 0.002853

0.387096774193548 0.7374 0.1318 0.02537 0.008949 0.005966 0.002838

0.419354838709677 0.7374 0.1313 0.02537 0.008904 0.005936 0.002836

0.451612903225806 0.7374 0.1306 0.02532 0.008863 0.005909 0.002792

0.483870967741936 0.7374 0.1304 0.02522 0.008828 0.005886 0.002785

0.516129032258065 0.7374 0.1298 0.0252 0.008819 0.005879 0.002772

0.548387096774194 0.7374 0.1291 0.02504 0.008763 0.005842 0.002762

0.580645161290323 0.7374 0.129 0.02488 0.008708 0.005805 0.002752

0.612903225806452 0.7374 0.128 0.02478 0.008675 0.005783 0.002743

0.645161290322581 0.7374 0.1279 0.02469 0.00864 0.00576 0.002711

0.67741935483871 0.7374 0.1275 0.02451 0.00858 0.00572 0.002708

0.709677419354839 0.7374 0.126 0.02443 0.008562 0.005708 0.002698

0.741935483870968 0.7374 0.1256 0.0241 0.008434 0.005623 0.002694

0.774193548387097 0.7374 0.1241 0.02394 0.008379 0.005586 0.002686

0.806451612903226 0.7374 0.124 0.02386 0.008368 0.005579 0.002679

0.838709677419355 0.7374 0.124 0.02377 0.008328 0.005552 0.002672

0.870967741935484 0.7374 0.1238 0.02364 0.008274 0.005516 0.002668

0.903225806451613 0.7374 0.1236 0.02364 0.008273 0.005515 0.002667

0.935483870967742 0.7374 0.1218 0.02332 0.008167 0.005445 0.00266

0.967741935483871 0.7374 0.1211 0.02322 0.008127 0.005418 0.00263

0.1 0.80652 0.17488 0.035437 0.012403 0.0082699 0.0033751

Average of yearly averages: 0.0029208

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_tx_wheat

Metfile: w13958.dvf

PRZM scenario: TXwheatOP.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weightmwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09atm-m^3/mol

Vapor Pressure vapr 1.40e-08torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate:TAPP 0.118 kg/ha

Application Efficiency: APPEFF0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 18-06 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 127 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.093 kg/ha

Record 17: FILTRA

IPSCND1

UPTKF

Record 18: PLVKRT
-Page 92 of 116-

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)

Conservation Reserve

stored as fpe_tx_conserve.out

Chemical: fpe

PRZM environment: TXalfalfaOP.txt modified Thuday, 14 June 2007 at 11:23:54

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 13:47:26

Metfile: w13958.dvf modified Wedday, 3 July 2002 at 10:06:24

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.6999 0.1813 0.04377 0.01538 0.01055 0.003357

1962 0.6999 0.2151 0.05536 0.01958 0.01307 0.0039

1963 0.6999 0.1769 0.06735 0.02357 0.01572 0.004552

1964 0.6999 0.1981 0.04669 0.01692 0.0114 0.0035

1965 0.6999 0.2443 0.05764 0.02081 0.01387 0.004147

1966 0.6999 0.2037 0.0483 0.01853 0.01235 0.004236

1967 0.6999 0.1665 0.03902 0.01488 0.009924 0.003192

1968 0.6999 0.2183 0.0518 0.01863 0.01242 0.003778

1969 0.6999 0.2673 0.06359 0.02454 0.01636 0.004745

1970 0.6999 0.228 0.05387 0.02044 0.01363 0.004062

1971 0.6999 0.1914 0.04574 0.0168 0.01122 0.004314

1972 0.6999 0.1698 0.04006 0.01671 0.01114 0.003505

1973 0.6999 0.1881 0.0472 0.01688 0.01126 0.003525

1974 0.6999 0.1802 0.04383 0.0157 0.01047 0.003508

1975 0.6999 0.2022 0.04829 0.02274 0.01516 0.004498

1976 0.6999 0.192 0.05216 0.01862 0.01241 0.00378

1977 0.6999 0.193 0.0475 0.01889 0.0126 0.003794

1978 0.6999 0.2115 0.05414 0.01993 0.01329 0.003989

1979 0.7806 0.2258 0.05309 0.01876 0.01253 0.003838

1980 0.6999 0.1912 0.06881 0.02445 0.0163 0.004706

1981 0.6999 0.204 0.04763 0.01705 0.01148 0.003533

1982 0.6999 0.1813 0.04391 0.01681 0.0112 0.003445

1983 0.6999 0.2941 0.07161 0.02591 0.01729 0.004991

1984 0.6999 0.1838 0.04341 0.01529 0.01023 0.00321

1985 0.6999 0.178 0.04247 0.01518 0.01013 0.003178

1986 0.6999 0.181 0.04276 0.01834 0.01222 0.003729

1987 0.6999 0.2111 0.05005 0.01758 0.0119 0.003634

1988 0.6999 0.1975 0.04738 0.01679 0.01123 0.00345

1989 0.713 0.2029 0.04948 0.01772 0.01181 0.003644

1990 0.6999 0.1928 0.0458 0.01747 0.01164 0.003572

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 0.7806 0.2941 0.07161 0.02591 0.01729 0.004991

0.0645161290322581 0.713 0.2673 0.06881 0.02454 0.01636 0.004745

0.0967741935483871 0.6999 0.2443 0.06735 0.02445 0.0163 0.004706

0.129032258064516 0.6999 0.228 0.06359 0.02357 0.01572 0.004552

0.161290322580645 0.6999 0.2258 0.05764 0.02274 0.01516 0.004498

0.193548387096774 0.6999 0.2183 0.05536 0.02081 0.01387 0.004314

0.225806451612903 0.6999 0.2151 0.05414 0.02044 0.01363 0.004236

0.258064516129032 0.6999 0.2115 0.05387 0.01993 0.01329 0.004147

0.290322580645161 0.6999 0.2111 0.05309 0.01958 0.01307 0.004062
-Page 93 of 116-

0.32258064516129 0.6999 0.204 0.05216 0.01889 0.0126 0.003989

0.354838709677419 0.6999 0.2037 0.0518 0.01876 0.01253 0.0039

0.387096774193548 0.6999 0.2029 0.05005 0.01863 0.01242 0.003838

0.419354838709677 0.6999 0.2022 0.04948 0.01862 0.01241 0.003794

0.451612903225806 0.6999 0.1981 0.0483 0.01853 0.01235 0.00378

0.483870967741936 0.6999 0.1975 0.04829 0.01834 0.01222 0.003778

0.516129032258065 0.6999 0.193 0.04763 0.01772 0.0119 0.003729

0.548387096774194 0.6999 0.1928 0.0475 0.01758 0.01181 0.003644

0.580645161290323 0.6999 0.192 0.04738 0.01747 0.01164 0.003634

0.612903225806452 0.6999 0.1914 0.0472 0.01705 0.01148 0.003572

0.645161290322581 0.6999 0.1912 0.04669 0.01692 0.0114 0.003533

0.67741935483871 0.6999 0.1881 0.0458 0.01688 0.01126 0.003525

0.709677419354839 0.6999 0.1838 0.04574 0.01681 0.01123 0.003508

0.741935483870968 0.6999 0.1813 0.04391 0.0168 0.01122 0.003505

0.774193548387097 0.6999 0.1813 0.04383 0.01679 0.0112 0.0035

0.806451612903226 0.6999 0.181 0.04377 0.01671 0.01114 0.00345

0.838709677419355 0.6999 0.1802 0.04341 0.0157 0.01055 0.003445

0.870967741935484 0.6999 0.178 0.04276 0.01538 0.01047 0.003357

0.903225806451613 0.6999 0.1769 0.04247 0.01529 0.01023 0.00321

0.935483870967742 0.6999 0.1698 0.04006 0.01518 0.01013 0.003192

0.967741935483871 0.6999 0.1665 0.03902 0.01488 0.009924 0.003178

0.1 0.6999 0.24267 0.066974 0.024362 0.016242 0.0046906

Average of yearly averages: 0.00384373333333333

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_tx_conserve

Metfile: w13958.dvf

PRZM scenario: TXalfalfaOP.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weightmwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09atm-m^3/mol

Vapor Pressure vapr 1.40e-08torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate:TAPP 0.112 kg/ha

Application Efficiency: APPEFF0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 21-03 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 14 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.031 kg/ha

Interval 2 interval 120 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.067 kg/ha

Record 17: FILTRA
-Page 94 of 116-

IPSCND1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)

Cotton

stored as fpe_nc_cotton.out

Chemical: fpe

PRZM environment: NCcottonSTD.txt modified Tueday, 29 May 2007 at 13:58:38

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 13:47:26

Metfile: w13722.dvf modified Wedday, 3 July 2002 at 10:05:50

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.7374 0.1487 0.02863 0.01002 0.006682 0.001648

1962 0.7374 0.1466 0.03249 0.01137 0.007582 0.00187

1963 0.7374 0.147 0.02809 0.009875 0.006583 0.001623

1964 0.7374 0.138 0.0272 0.009532 0.006355 0.001563

1965 0.7374 0.2291 0.0483 0.01691 0.01127 0.002779

1966 0.7374 0.1457 0.02943 0.01031 0.006873 0.001695

1967 0.7374 0.1514 0.03489 0.01222 0.008146 0.002009

1968 0.7374 0.1456 0.02863 0.0101 0.006732 0.001655

1969 0.7374 0.1921 0.03691 0.01292 0.008615 0.002124

1970 0.7374 0.1486 0.02839 0.01019 0.006792 0.001675

1971 0.7374 0.1401 0.02674 0.009495 0.00633 0.001561

1972 0.7374 0.1576 0.03323 0.01164 0.00776 0.001908

1973 0.7374 0.1429 0.02851 0.009987 0.006658 0.001642

1974 0.7374 0.1533 0.02954 0.01034 0.006896 0.001701

1975 0.7374 0.1441 0.02752 0.00972 0.00648 0.001598

1976 0.7374 0.1426 0.02726 0.009542 0.006362 0.001566

1977 0.7374 0.1475 0.02817 0.009904 0.006609 0.00163

1978 1.142 0.215 0.04135 0.01448 0.009655 0.002381

1979 0.7374 0.1578 0.0311 0.01095 0.007298 0.0018

1980 0.7374 0.1374 0.02986 0.01046 0.006973 0.001715

1981 0.7374 0.1277 0.02434 0.009082 0.006055 0.001493

1982 0.7468 0.2318 0.04521 0.01583 0.01055 0.002602

1983 0.9141 0.1845 0.03536 0.01238 0.008252 0.002035

1984 0.7374 0.1381 0.02656 0.009342 0.006228 0.001531

1985 0.7374 0.142 0.02796 0.009809 0.006539 0.001612

1986 0.7374 0.1301 0.02495 0.008852 0.005901 0.001455

1987 0.7374 0.135 0.02634 0.009219 0.006147 0.001516

1988 0.7374 0.1556 0.02981 0.01044 0.006959 0.001711

1989 0.7374 0.1388 0.0267 0.009347 0.006231 0.001536

1990 0.7374 0.1376 0.02625 0.009204 0.006136 0.001513

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 1.142 0.2318 0.0483 0.01691 0.01127 0.002779

0.0645161290322581 0.9141 0.2291 0.04521 0.01583 0.01055 0.002602

0.0967741935483871 0.7468 0.215 0.04135 0.01448 0.009655 0.002381

0.129032258064516 0.7374 0.1921 0.03691 0.01292 0.008615 0.002124

0.161290322580645 0.7374 0.1845 0.03536 0.01238 0.008252 0.002035

0.193548387096774 0.7374 0.1578 0.03489 0.01222 0.008146 0.002009
-Page 95 of 116-

0.225806451612903 0.7374 0.1576 0.03323 0.01164 0.00776 0.001908

0.258064516129032 0.7374 0.1556 0.03249 0.01137 0.007582 0.00187

0.290322580645161 0.7374 0.1533 0.0311 0.01095 0.007298 0.0018

0.32258064516129 0.7374 0.1514 0.02986 0.01046 0.006973 0.001715

0.354838709677419 0.7374 0.1487 0.02981 0.01044 0.006959 0.001711

0.387096774193548 0.7374 0.1486 0.02954 0.01034 0.006896 0.001701

0.419354838709677 0.7374 0.1475 0.02943 0.01031 0.006873 0.001695

0.451612903225806 0.7374 0.147 0.02863 0.01019 0.006792 0.001675

0.483870967741936 0.7374 0.1466 0.02863 0.0101 0.006732 0.001655

0.516129032258065 0.7374 0.1457 0.02851 0.01002 0.006682 0.001648

0.548387096774194 0.7374 0.1456 0.02839 0.009987 0.006658 0.001642

0.580645161290323 0.7374 0.1441 0.02817 0.009904 0.006609 0.00163

0.612903225806452 0.7374 0.1429 0.02809 0.009875 0.006583 0.001623

0.645161290322581 0.7374 0.1426 0.02796 0.009809 0.006539 0.001612

0.67741935483871 0.7374 0.142 0.02752 0.00972 0.00648 0.001598

0.709677419354839 0.7374 0.1401 0.02726 0.009542 0.006362 0.001566

0.741935483870968 0.7374 0.1388 0.0272 0.009532 0.006355 0.001563

0.774193548387097 0.7374 0.1381 0.02674 0.009495 0.00633 0.001561

0.806451612903226 0.7374 0.138 0.0267 0.009347 0.006231 0.001536

0.838709677419355 0.7374 0.1376 0.02656 0.009342 0.006228 0.001531

0.870967741935484 0.7374 0.1374 0.02634 0.009219 0.006147 0.001516

0.903225806451613 0.7374 0.135 0.02625 0.009204 0.006136 0.001513

0.935483870967742 0.7374 0.1301 0.02495 0.009082 0.006055 0.001493

0.967741935483871 0.7374 0.1277 0.02434 0.008852 0.005901 0.001455

0.1 0.74586 0.21271 0.040906 0.014324 0.009551 0.0023553

Average of yearly averages: 0.00177156666666667

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_nc_cotton

Metfile: w13722.dvf

PRZM scenario: NCcottonSTD.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weightmwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09atm-m^3/mol

Vapor Pressure vapr 1.40e-08torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate:TAPP 0.118 kg/ha

Application Efficiency: APPEFF0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 08-06 dd/mm or dd/mmm or dd-mm or dd-mmm

Record 17: FILTRA

IPSCND1
-Page 96 of 116-

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run)

Ornamental

stored as fpe_fl_ornamental.out

Chemical: fpe

PRZM environment: FLnurserySTD_V2.txt modified Tueday, 27 May 2008 at 

11:22:34

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 

13:47:26

Metfile: w12839.dvf modified Wedday, 3 July 2002 at 10:04:28

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 1.895 0.3707 0.1167 0.05837 0.03892 0.009596

1962 1.213 0.2765 0.1016 0.05403 0.03602 0.008882

1963 1.213 0.2433 0.09321 0.05235 0.0349 0.008606

1964 1.26 0.2344 0.08942 0.04829 0.0322 0.007917

1965 1.243 0.2417 0.09539 0.05032 0.03355 0.008273

1966 1.256 0.2784 0.1208 0.06107 0.04073 0.01004

1967 1.212 0.2492 0.09992 0.05235 0.0349 0.008606

1968 1.212 0.2832 0.09929 0.05239 0.03493 0.008588

1969 1.3 0.2899 0.1049 0.05687 0.03791 0.009348

1970 1.469 0.2539 0.09791 0.05071 0.03382 0.008338

1971 1.265 0.2557 0.09474 0.05057 0.03372 0.008314

1972 1.255 0.2556 0.09806 0.05228 0.03486 0.008571

1973 1.225 0.2333 0.09224 0.05125 0.03417 0.008425

1974 1.215 0.2333 0.09084 0.04856 0.03238 0.007983

1975 1.213 0.2435 0.09064 0.04776 0.03184 0.00785

1976 1.27 0.304 0.1185 0.05899 0.03933 0.009671

1977 1.213 0.2366 0.09082 0.05598 0.03732 0.009202

1978 1.264 0.2727 0.1004 0.05465 0.03644 0.008984

1979 1.624 0.3064 0.1049 0.07085 0.04723 0.01165

1980 1.902 0.5118 0.1989 0.08784 0.05856 0.0144

1981 1.335 0.2678 0.09555 0.05129 0.03419 0.008431

1982 1.276 0.2348 0.1214 0.06506 0.04337 0.01069

1983 1.212 0.2903 0.1079 0.05623 0.03748 0.009243

1984 1.739 0.584 0.1625 0.07972 0.05315 0.01307

1985 1.287 0.2565 0.09881 0.05241 0.03494 0.008615

1986 1.221 0.2762 0.1243 0.06212 0.04141 0.01021

1987 1.284 0.2761 0.1049 0.05593 0.03729 0.009194

1988 1.272 0.2704 0.09732 0.05213 0.03476 0.008547

1989 1.213 0.2468 0.09147 0.0487 0.03246 0.008005

1990 1.786 0.337 0.1561 0.07283 0.04855 0.01197

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 1.902 0.584 0.1989 0.08784 0.05856 0.0144

0.0645161290322581 1.895 0.5118 0.1625 0.07972 0.05315 0.01307

0.0967741935483871 1.786 0.3707 0.1561 0.07283 0.04855 0.01197

0.129032258064516 1.739 0.337 0.1243 0.07085 0.04723 0.01165

0.161290322580645 1.624 0.3064 0.1214 0.06506 0.04337 0.01069
-Page 97 of 116-

0.193548387096774 1.469 0.304 0.1208 0.06212 0.04141 0.01021

0.225806451612903 1.335 0.2903 0.1185 0.06107 0.04073 0.01004

0.258064516129032 1.3 0.2899 0.1167 0.05899 0.03933 0.009671

0.290322580645161 1.287 0.2832 0.1079 0.05837 0.03892 0.009596

0.32258064516129 1.284 0.2784 0.1049 0.05687 0.03791 0.009348

0.354838709677419 1.276 0.2765 0.1049 0.05623 0.03748 0.009243

0.387096774193548 1.272 0.2762 0.1049 0.05598 0.03732 0.009202

0.419354838709677 1.27 0.2761 0.1016 0.05593 0.03729 0.009194

0.451612903225806 1.265 0.2727 0.1004 0.05465 0.03644 0.008984

0.483870967741936 1.264 0.2704 0.09992 0.05403 0.03602 0.008882

0.516129032258065 1.26 0.2678 0.09929 0.05241 0.03494 0.008615

0.548387096774194 1.256 0.2565 0.09881 0.05239 0.03493 0.008606

0.580645161290323 1.255 0.2557 0.09806 0.05235 0.0349 0.008606

0.612903225806452 1.243 0.2556 0.09791 0.05235 0.0349 0.008588

0.645161290322581 1.225 0.2539 0.09732 0.05228 0.03486 0.008571

0.67741935483871 1.221 0.2492 0.09555 0.05213 0.03476 0.008547

0.709677419354839 1.215 0.2468 0.09539 0.05129 0.03419 0.008431

0.741935483870968 1.213 0.2435 0.09474 0.05125 0.03417 0.008425

0.774193548387097 1.213 0.2433 0.09321 0.05071 0.03382 0.008338

0.806451612903226 1.213 0.2417 0.09224 0.05057 0.03372 0.008314

0.838709677419355 1.213 0.2366 0.09147 0.05032 0.03355 0.008273

0.870967741935484 1.213 0.2348 0.09084 0.0487 0.03246 0.008005

0.903225806451613 1.212 0.2344 0.09082 0.04856 0.03238 0.007983

0.935483870967742 1.212 0.2333 0.09064 0.04829 0.0322 0.007917

0.967741935483871 1.212 0.2333 0.08942 0.04776 0.03184 0.00785

0.1 1.7813 0.36733 0.15292 0.072632 0.048418 0.011938

Average of yearly averages:

0.00937396666666667

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_fl_ornamental

Metfile: w12839.dvf

PRZM scenario: FLnurserySTD_V2.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weight mwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09 atm-m^3/mol

Vapor Pressure vapr 1.40e-08 torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate: TAPP 0.194 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 21-03 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 14 days Set to 0 or delete line for single app.
-Page 98 of 116-

app. rate 1 apprate 0.194 kg/ha

Interval 2 interval 14 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.194 kg/ha

Interval 3 interval 14 days Set to 0 or delete line for single app.

app. rate 3 apprate 0.013 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of 

entire run)

Right-of-way

stored as fpe_bss_row.out

Chemical: fpe

PRZM environment: RightOfWayBSS.txt modified Tueday, 28 March 2006 at 

15:53:28

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 

13:47:26

Metfile: w13958.dvf modified Wedday, 3 July 2002 at 10:06:24

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 1.212 0.314 0.1151 0.0611 0.04237 0.01045

1962 1.753 0.4148 0.1534 0.07771 0.05233 0.0129

1963 2.173 0.6639 0.1868 0.08292 0.05567 0.01373

1964 1.212 0.3432 0.1169 0.0633 0.04291 0.01055

1965 1.212 0.4232 0.1373 0.07396 0.04931 0.01216

1966 1.245 0.3528 0.1263 0.07577 0.05053 0.01246

1967 1.212 0.2895 0.1092 0.05922 0.03976 0.009806

1968 1.212 0.3781 0.1284 0.06996 0.04664 0.01147

1969 1.213 0.4794 0.1517 0.08353 0.05569 0.01373

1970 1.34 0.399 0.1318 0.07821 0.05216 0.01286

1971 1.227 0.3315 0.1176 0.06351 0.04267 0.01068

1972 1.212 0.294 0.1027 0.06303 0.04202 0.01033

1973 1.235 0.3329 0.1306 0.06974 0.04673 0.01152

1974 1.212 0.3185 0.1151 0.06436 0.04291 0.01058

1975 1.979 0.4668 0.1469 0.0945 0.06308 0.01555

1976 4.801 1.121 0.2999 0.1293 0.08623 0.0212

1977 1.231 0.3816 0.1511 0.0774 0.05169 0.01275

1978 1.212 0.3663 0.1361 0.07834 0.05227 0.01289

1979 1.49 0.4428 0.1418 0.07462 0.05165 0.01274

1980 1.212 0.3313 0.1433 0.0799 0.05327 0.0131

1981 1.212 0.3533 0.117 0.06121 0.04134 0.01019

1982 1.212 0.3223 0.1536 0.07791 0.05194 0.01281

1983 1.212 0.5055 0.1655 0.09161 0.06128 0.01511

1984 1.212 0.321 0.1109 0.05769 0.03877 0.009539

1985 1.212 0.3083 0.1101 0.05855 0.03922 0.009673

1986 1.212 0.3135 0.1091 0.07248 0.04832 0.01191

1987 1.212 0.3656 0.1249 0.06443 0.04409 0.01087

1988 1.212 0.342 0.1216 0.06491 0.04378 0.01077

1989 1.301 0.3929 0.129 0.07356 0.04904 0.01209

1990 1.212 0.334 0.117 0.07474 0.04983 0.01229
-Page 99 of 116-

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 4.801 1.121 0.2999 0.1293 0.08623 0.0212

0.0645161290322581 2.173 0.6639 0.1868 0.0945 0.06308 0.01555

0.0967741935483871 1.979 0.5055 0.1655 0.09161 0.06128 0.01511

0.129032258064516 1.753 0.4794 0.1536 0.08353 0.05569 0.01373

0.161290322580645 1.49 0.4668 0.1534 0.08292 0.05567 0.01373

0.193548387096774 1.34 0.4428 0.1517 0.0799 0.05327 0.0131

0.225806451612903 1.301 0.4232 0.1511 0.07834 0.05233 0.0129

0.258064516129032 1.245 0.4148 0.1469 0.07821 0.05227 0.01289

0.290322580645161 1.235 0.399 0.1433 0.07791 0.05216 0.01286

0.32258064516129 1.231 0.3929 0.1418 0.07771 0.05194 0.01281

0.354838709677419 1.227 0.3816 0.1373 0.0774 0.05169 0.01275

0.387096774193548 1.213 0.3781 0.1361 0.07577 0.05165 0.01274

0.419354838709677 1.212 0.3663 0.1318 0.07474 0.05053 0.01246

0.451612903225806 1.212 0.3656 0.1306 0.07462 0.04983 0.01229

0.483870967741936 1.212 0.3533 0.129 0.07396 0.04931 0.01216

0.516129032258065 1.212 0.3528 0.1284 0.07356 0.04904 0.01209

0.548387096774194 1.212 0.3432 0.1263 0.07248 0.04832 0.01191

0.580645161290323 1.212 0.342 0.1249 0.06996 0.04673 0.01152

0.612903225806452 1.212 0.334 0.1216 0.06974 0.04664 0.01147

0.645161290322581 1.212 0.3329 0.1176 0.06491 0.04409 0.01087

0.67741935483871 1.212 0.3315 0.117 0.06443 0.04378 0.01077

0.709677419354839 1.212 0.3313 0.117 0.06436 0.04291 0.01068

0.741935483870968 1.212 0.3223 0.1169 0.06351 0.04291 0.01058

0.774193548387097 1.212 0.321 0.1151 0.0633 0.04267 0.01055

0.806451612903226 1.212 0.3185 0.1151 0.06303 0.04237 0.01045

0.838709677419355 1.212 0.314 0.1109 0.06121 0.04202 0.01033

0.870967741935484 1.212 0.3135 0.1101 0.0611 0.04134 0.01019

0.903225806451613 1.212 0.3083 0.1092 0.05922 0.03976 0.009806

0.935483870967742 1.212 0.294 0.1091 0.05855 0.03922 0.009673

0.967741935483871 1.212 0.2895 0.1027 0.05769 0.03877 0.009539

0.1 1.9564 0.50289 0.16431 0.090802 0.060721 0.014972

Average of yearly averages: 0.0122236

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_bss_row

Metfile: w13958.dvf

PRZM scenario: RightOfWayBSS.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weight mwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09 atm-m^3/mol

Vapor Pressure vapr 1.40e-08 torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual
-Page 100 of 116-

Incorporation Depth: DEPI 0 cm

Application Rate: TAPP 0.194 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 21-03 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 14 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.194 kg/ha

Interval 2 interval 14 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.194 kg/ha

Interval 3 interval 14 days Set to 0 or delete line for single app.

app. rate 3 apprate 0.013 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of 

entire run)

Soybean

stored as fpe_ms_soy2.out

Chemical: fpe

PRZM environment: MSsoybeanSTD.txt modified Tueday, 29 May 2007 at 13:58:06

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 

13:47:26

Metfile: w03940.dvf modified Wedday, 3 July 2002 at 10:05:46

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.6999 0.1917 0.04772 0.01671 0.01114 0.00394

1962 0.6999 0.1838 0.04353 0.01525 0.01016 0.003559

1963 0.6999 0.1594 0.03785 0.01333 0.008894 0.003174

1964 0.6999 0.2037 0.04766 0.01671 0.01114 0.00401

1965 0.6999 0.1601 0.03798 0.0133 0.008866 0.003462

1966 0.6999 0.1866 0.04488 0.01607 0.01071 0.00398

1967 0.6999 0.1541 0.03977 0.01401 0.009342 0.003627

1968 0.6999 0.1691 0.0424 0.01485 0.009899 0.003559

1969 0.6999 0.1725 0.04092 0.01433 0.009552 0.003479

1970 0.6999 0.1989 0.03924 0.01373 0.009155 0.004436

1971 0.6999 0.1853 0.0485 0.017 0.01133 0.003811

1972 0.6999 0.1667 0.0414 0.0145 0.009666 0.003449

1973 0.6999 0.195 0.0501 0.01754 0.0117 0.003948

1974 0.6999 0.1796 0.04211 0.01476 0.009842 0.003667

1975 0.6999 0.1825 0.04391 0.01542 0.01028 0.003935

1976 0.6999 0.177 0.04835 0.01701 0.01134 0.004182

1977 0.6999 0.1648 0.03864 0.01362 0.009087 0.003501

1978 0.6999 0.1742 0.04844 0.01696 0.01131 0.004039

1979 0.7705 0.1954 0.04741 0.01662 0.01108 0.003924

1980 0.6999 0.2472 0.05713 0.02018 0.01346 0.004614

1981 0.6999 0.1475 0.03624 0.01286 0.008571 0.003262

1982 0.6999 0.1808 0.04233 0.01493 0.009951 0.003625

1983 0.7 0.1976 0.04644 0.01723 0.01149 0.003971

1984 0.6999 0.1805 0.04327 0.01516 0.01011 0.003468

1985 0.748 0.1822 0.04263 0.01493 0.009955 0.003532

1986 0.6999 0.1765 0.04155 0.01472 0.009816 0.004069
-Page 101 of 116-

1987 0.6999 0.1867 0.04546 0.01592 0.01061 0.003988

1988 1.213 0.3029 0.06618 0.02316 0.01546 0.005106

1989 0.6999 0.1818 0.04427 0.01572 0.01048 0.003808

1990 0.6999 0.1812 0.04653 0.01632 0.01088 0.003915

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 1.213 0.3029 0.06618 0.02316 0.01546 0.005106

0.0645161290322581 0.7705 0.2472 0.05713 0.02018 0.01346 0.004614

0.0967741935483871 0.748 0.2037 0.0501 0.01754 0.0117 0.004436

0.129032258064516 0.7 0.1989 0.0485 0.01723 0.01149 0.004182

0.161290322580645 0.6999 0.1976 0.04844 0.01701 0.01134 0.004069

0.193548387096774 0.6999 0.1954 0.04835 0.017 0.01133 0.004039

0.225806451612903 0.6999 0.195 0.04772 0.01696 0.01131 0.00401

0.258064516129032 0.6999 0.1917 0.04766 0.01671 0.01114 0.003988

0.290322580645161 0.6999 0.1867 0.04741 0.01671 0.01114 0.00398

0.32258064516129 0.6999 0.1866 0.04653 0.01662 0.01108 0.003971

0.354838709677419 0.6999 0.1853 0.04644 0.01632 0.01088 0.003948

0.387096774193548 0.6999 0.1838 0.04546 0.01607 0.01071 0.00394

0.419354838709677 0.6999 0.1825 0.04488 0.01592 0.01061 0.003935

0.451612903225806 0.6999 0.1822 0.04427 0.01572 0.01048 0.003924

0.483870967741936 0.6999 0.1818 0.04391 0.01542 0.01028 0.003915

0.516129032258065 0.6999 0.1812 0.04353 0.01525 0.01016 0.003811

0.548387096774194 0.6999 0.1808 0.04327 0.01516 0.01011 0.003808

0.580645161290323 0.6999 0.1805 0.04263 0.01493 0.009955 0.003667

0.612903225806452 0.6999 0.1796 0.0424 0.01493 0.009951 0.003627

0.645161290322581 0.6999 0.177 0.04233 0.01485 0.009899 0.003625

0.67741935483871 0.6999 0.1765 0.04211 0.01476 0.009842 0.003559

0.709677419354839 0.6999 0.1742 0.04155 0.01472 0.009816 0.003559

0.741935483870968 0.6999 0.1725 0.0414 0.0145 0.009666 0.003532

0.774193548387097 0.6999 0.1691 0.04092 0.01433 0.009552 0.003501

0.806451612903226 0.6999 0.1667 0.03977 0.01401 0.009342 0.003479

0.838709677419355 0.6999 0.1648 0.03924 0.01373 0.009155 0.003468

0.870967741935484 0.6999 0.1601 0.03864 0.01362 0.009087 0.003462

0.903225806451613 0.6999 0.1594 0.03798 0.01333 0.008894 0.003449

0.935483870967742 0.6999 0.1541 0.03785 0.0133 0.008866 0.003262

0.967741935483871 0.6999 0.1475 0.03624 0.01286 0.008571 0.003174

0.1 0.7432 0.20322 0.04994 0.017509 0.011679 0.0044106

Average of yearly averages:

0.00383466666666667

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_ms_soy2

Metfile: w03940.dvf

PRZM scenario: MSsoybeanSTD.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weight mwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09 atm-m^3/mol

Vapor Pressure vapr 1.40e-08 torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L
-Page 102 of 116-

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate: TAPP 0.112 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 23-04 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 14 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.031 kg/ha

Interval 2 interval 157 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.067 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of 

entire run)

Turf

stored as fpe_ca_turf.out

Chemical: fpe

PRZM environment: CATurfRLF.txt modified Tueday, 20 February 2007 at 

13:03:48

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 

13:47:26

Metfile: w23234.dvf modified Wedday, 3 July 2002 at 10:04:22

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 1.213 0.4206 0.1622 0.08795 0.05864 0.01446

1962 1.213 0.4682 0.1771 0.09221 0.06147 0.01516

1963 1.215 0.4664 0.2322 0.1139 0.07594 0.01872

1964 1.212 0.4402 0.1743 0.09274 0.06183 0.0152

1965 1.213 0.4352 0.1846 0.09747 0.06498 0.01602

1966 1.212 0.4422 0.1669 0.08714 0.05809 0.01432

1967 1.225 0.6814 0.2632 0.1276 0.08505 0.02097

1968 1.212 0.4132 0.1657 0.0891 0.0594 0.01461

1969 1.212 0.4563 0.1808 0.09515 0.06344 0.01564

1970 1.215 0.4206 0.1698 0.0886 0.05907 0.01457

1971 1.212 0.4359 0.1776 0.09508 0.06339 0.01563

1972 1.213 0.4092 0.163 0.08762 0.05841 0.01436

1973 1.222 0.4442 0.1694 0.08848 0.05899 0.01454

1974 1.217 0.4259 0.1755 0.09225 0.0615 0.01516

1975 2.538 0.9275 0.2917 0.1375 0.09169 0.02261

1976 1.213 0.4524 0.1798 0.09544 0.06363 0.01565

1977 1.212 0.4474 0.1733 0.09145 0.06097 0.01503

1978 1.218 0.4151 0.1676 0.08977 0.05985 0.01476

1979 1.213 0.4153 0.177 0.09203 0.06135 0.01513

1980 1.215 0.4265 0.1662 0.08813 0.05876 0.01445

1981 1.212 0.4216 0.1645 0.08728 0.05819 0.01435
-Page 103 of 116-

1982 1.221 0.4461 0.2193 0.1161 0.07743 0.01909

1983 1.213 0.4453 0.1734 0.09168 0.06112 0.01507

1984 1.212 0.3971 0.1587 0.08403 0.05602 0.01378

1985 1.216 0.4516 0.1933 0.0959 0.06393 0.01576

1986 1.212 0.3995 0.1597 0.08463 0.05642 0.01391

1987 1.212 0.4037 0.1547 0.08206 0.0547 0.01349

1988 1.214 0.5573 0.1868 0.09496 0.0633 0.01557

1989 1.212 0.4046 0.1501 0.07848 0.05232 0.0129

1990 1.212 0.4299 0.1616 0.08441 0.05628 0.01388

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 2.538 0.9275 0.2917 0.1375 0.09169 0.02261

0.0645161290322581 1.225 0.6814 0.2632 0.1276 0.08505 0.02097

0.0967741935483871 1.222 0.5573 0.2322 0.1161 0.07743 0.01909

0.129032258064516 1.221 0.4682 0.2193 0.1139 0.07594 0.01872

0.161290322580645 1.218 0.4664 0.1933 0.09747 0.06498 0.01602

0.193548387096774 1.217 0.4563 0.1868 0.0959 0.06393 0.01576

0.225806451612903 1.216 0.4524 0.1846 0.09544 0.06363 0.01565

0.258064516129032 1.215 0.4516 0.1808 0.09515 0.06344 0.01564

0.290322580645161 1.215 0.4474 0.1798 0.09508 0.06339 0.01563

0.32258064516129 1.215 0.4461 0.1776 0.09496 0.0633 0.01557

0.354838709677419 1.214 0.4453 0.1771 0.09274 0.06183 0.0152

0.387096774193548 1.213 0.4442 0.177 0.09225 0.0615 0.01516

0.419354838709677 1.213 0.4422 0.1755 0.09221 0.06147 0.01516

0.451612903225806 1.213 0.4402 0.1743 0.09203 0.06135 0.01513

0.483870967741936 1.213 0.4359 0.1734 0.09168 0.06112 0.01507

0.516129032258065 1.213 0.4352 0.1733 0.09145 0.06097 0.01503

0.548387096774194 1.213 0.4299 0.1698 0.08977 0.05985 0.01476

0.580645161290323 1.213 0.4265 0.1694 0.0891 0.0594 0.01461

0.612903225806452 1.212 0.4259 0.1676 0.0886 0.05907 0.01457

0.645161290322581 1.212 0.4216 0.1669 0.08848 0.05899 0.01454

0.67741935483871 1.212 0.4206 0.1662 0.08813 0.05876 0.01446

0.709677419354839 1.212 0.4206 0.1657 0.08795 0.05864 0.01445

0.741935483870968 1.212 0.4153 0.1645 0.08762 0.05841 0.01436

0.774193548387097 1.212 0.4151 0.163 0.08728 0.05819 0.01435

0.806451612903226 1.212 0.4132 0.1622 0.08714 0.05809 0.01432

0.838709677419355 1.212 0.4092 0.1616 0.08463 0.05642 0.01391

0.870967741935484 1.212 0.4046 0.1597 0.08441 0.05628 0.01388

0.903225806451613 1.212 0.4037 0.1587 0.08403 0.05602 0.01378

0.935483870967742 1.212 0.3995 0.1547 0.08206 0.0547 0.01349

0.967741935483871 1.212 0.3971 0.1501 0.07848 0.05232 0.0129

0.1 1.2219 0.54839 0.23091 0.11588 0.077281 0.019053

Average of yearly averages: 0.015493

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_ca_turf

Metfile: w23234.dvf

PRZM scenario: CATurfRLF.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weight mwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09 atm-m^3/mol
-Page 104 of 116-

Vapor Pressure vapr 1.40e-08 torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate: TAPP 0.194 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 21-03 dd/mm or dd/mmm or dd-mm or dd-mmm

Interval 1 interval 14 days Set to 0 or delete line for single app.

app. rate 1 apprate 0.194 kg/ha

Interval 2 interval 14 days Set to 0 or delete line for single app.

app. rate 2 apprate 0.194 kg/ha

Interval 3 interval 14 days Set to 0 or delete line for single app.

app. rate 3 apprate 0.013 kg/ha

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of 

entire run)

Grass grown for seed

stored as fpe_ca_grass.out

Chemical: fpe

PRZM environment: CATurfRLF.txt modified Tueday, 20 February 2007 at 

13:03:48

EXAMS environment: pond298.exv modified Wedday, 15 November 2006 at 

13:47:26

Metfile: w23234.dvf modified Wedday, 3 July 2002 at 10:04:22

Water segment concentrations (ppb)

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly

1961 0.5811 0.2016 0.04084 0.0143 0.009535 0.002351

1962 0.5811 0.2244 0.04654 0.01629 0.01086 0.002678

1963 0.5811 0.2102 0.06571 0.02301 0.01534 0.003782

1964 0.5811 0.211 0.04324 0.01513 0.01009 0.002481

1965 0.5811 0.2086 0.04327 0.01517 0.01011 0.002494

1966 0.5811 0.212 0.04352 0.01523 0.01016 0.002504

1967 0.5811 0.2079 0.05772 0.02025 0.0135 0.003329

1968 0.5811 0.1981 0.03999 0.014 0.009331 0.002294

1969 0.5811 0.2081 0.04315 0.01511 0.01007 0.002484

1970 0.5811 0.1871 0.03731 0.01306 0.008707 0.002147

1971 0.5811 0.2089 0.04351 0.01523 0.01015 0.002504

1972 0.5813 0.1961 0.03949 0.01382 0.009216 0.002266

1973 0.5811 0.2129 0.04382 0.01534 0.01023 0.002522

1974 0.5811 0.2042 0.04492 0.01572 0.01048 0.002585

1975 1.217 0.4446 0.09142 0.032 0.02133 0.00526
-Page 105 of 116-

1976 0.5811 0.2169 0.04485 0.0157 0.01047 0.002574

1977 0.5811 0.2145 0.04417 0.01546 0.01031 0.002542

1978 0.5811 0.1821 0.0363 0.01274 0.008493 0.002094

1979 0.5811 0.1991 0.04669 0.01634 0.01089 0.002686

1980 0.5811 0.2044 0.04153 0.01454 0.009692 0.002383

1981 0.5811 0.2021 0.04105 0.01437 0.009579 0.002362

1982 0.5811 0.2138 0.05186 0.01816 0.0121 0.002985

1983 0.5811 0.2135 0.04337 0.01518 0.01012 0.002495

1984 0.5811 0.1836 0.03656 0.0128 0.008531 0.002098

1985 0.5811 0.2165 0.05674 0.01986 0.01324 0.003265

1986 0.5811 0.1841 0.03675 0.01287 0.008578 0.002115

1987 0.5811 0.1935 0.03886 0.0136 0.009068 0.002236

1988 0.5811 0.1893 0.03791 0.01332 0.00888 0.002184

1989 0.5811 0.194 0.03895 0.01364 0.009091 0.002242

1990 0.5811 0.2061 0.04198 0.0147 0.009797 0.002416

Sorted results

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly

0.032258064516129 1.217 0.4446 0.09142 0.032 0.02133 0.00526

0.0645161290322581 0.5813 0.2244 0.06571 0.02301 0.01534 0.003782

0.0967741935483871 0.5811 0.2169 0.05772 0.02025 0.0135 0.003329

0.129032258064516 0.5811 0.2165 0.05674 0.01986 0.01324 0.003265

0.161290322580645 0.5811 0.2145 0.05186 0.01816 0.0121 0.002985

0.193548387096774 0.5811 0.2138 0.04669 0.01634 0.01089 0.002686

0.225806451612903 0.5811 0.2135 0.04654 0.01629 0.01086 0.002678

0.258064516129032 0.5811 0.2129 0.04492 0.01572 0.01048 0.002585

0.290322580645161 0.5811 0.212 0.04485 0.0157 0.01047 0.002574

0.32258064516129 0.5811 0.211 0.04417 0.01546 0.01031 0.002542

0.354838709677419 0.5811 0.2102 0.04382 0.01534 0.01023 0.002522

0.387096774193548 0.5811 0.2089 0.04352 0.01523 0.01016 0.002504

0.419354838709677 0.5811 0.2086 0.04351 0.01523 0.01015 0.002504

0.451612903225806 0.5811 0.2081 0.04337 0.01518 0.01012 0.002495

0.483870967741936 0.5811 0.2079 0.04327 0.01517 0.01011 0.002494

0.516129032258065 0.5811 0.2061 0.04324 0.01513 0.01009 0.002484

0.548387096774194 0.5811 0.2044 0.04315 0.01511 0.01007 0.002481

0.580645161290323 0.5811 0.2042 0.04198 0.0147 0.009797 0.002416

0.612903225806452 0.5811 0.2021 0.04153 0.01454 0.009692 0.002383

0.645161290322581 0.5811 0.2016 0.04105 0.01437 0.009579 0.002362

0.67741935483871 0.5811 0.1991 0.04084 0.0143 0.009535 0.002351

0.709677419354839 0.5811 0.1981 0.03999 0.014 0.009331 0.002294

0.741935483870968 0.5811 0.1961 0.03949 0.01382 0.009216 0.002266

0.774193548387097 0.5811 0.194 0.03895 0.01364 0.009091 0.002242

0.806451612903226 0.5811 0.1935 0.03886 0.0136 0.009068 0.002236

0.838709677419355 0.5811 0.1893 0.03791 0.01332 0.00888 0.002184

0.870967741935484 0.5811 0.1871 0.03731 0.01306 0.008707 0.002147

0.903225806451613 0.5811 0.1841 0.03675 0.01287 0.008578 0.002115

0.935483870967742 0.5811 0.1836 0.03656 0.0128 0.008531 0.002098

0.967741935483871 0.5811 0.1821 0.0363 0.01274 0.008493 0.002094

0.1 0.5811 0.21686 0.057622 0.020211 0.013474 0.0033226

Average of yearly averages:

0.00261193333333333

Inputs generated by pe5.pl - Novemeber 2006

Data used for this run:

Output File: fpe_ca_grass
-Page 106 of 116-

Metfile: w23234.dvf

PRZM scenario: CATurfRLF.txt

EXAMS environment file: pond298.exv

Chemical Name: fpe

Description Variable Name Value Units Comments

Molecular weight mwt 361.8 g/mol

Henry's Law Const. henry 9.52e-09 atm-m^3/mol

Vapor Pressure vapr 1.40e-08 torr

Solubility sol 0.7 mg/L

Kd Kd 6.6 mg/L

Koc Koc mg/L

Photolysis half-life kdp 0.95 days Half-life

Aerobic Aquatic Metabolism kbacw 0.41 days Halfife

Anaerobic Aquatic Metabolism kbacs 2.7 days Halfife

Aerobic Soil Metabolism asm 1.2 days Halfife

Hydrolysis: pH 7 24.6 days Half-life

Method: CAM 2 integer See PRZM manual

Incorporation Depth: DEPI 0 cm

Application Rate: TAPP 0.093 kg/ha

Application Efficiency: APPEFF 0.95 fraction

Spray Drift DRFT 0.125 fraction of application rate applied to pond

Application Date Date 21-03 dd/mm or dd/mmm or dd-mm or dd-mmm

Record 17: FILTRA

IPSCND 1

UPTKF

Record 18: PLVKRT

PLDKRT

FEXTRC 0.5

Flag for Index Res. Run IR EPA Pond

Flag for runoff calc. RUNOFF none none, monthly or total(average of 

entire run)
-Page 107 of 116-

Appendix C. Example T-REX Input and Output for FPE (based on upper bound Kenaga 

EECs for use on ornamentals)
-Page 108 of 116-
-Page 109 of 116-

Appendix D. Example TERRPLANT (v. 1.2.2) Input and Output for FPE
-Page 110 of 116-

Appendix E. STIR Results for FPE
-Page 111 of 116-

Appendix F. SIP Results for FPE
-Page 112 of 116-

Appendix G. PFAM Modeling for Rice Applications of FPE

Tables G-1 and G-2 provide background information on rice practices in the United States.

Table G-1. Typical planting and harvesting dates*

State Planting Harvesting

Arkansas April 14 – May 1 Sep 9 – Oct 10

California May 1 - 25 Sep 15 – Nov 1

Louisiana March 28 – May 1 Aug 4 – Sep 15

Mississippi April 18 – May 16 Sep 5 – Oct 6

Texas March 23 – April 26 Aug 7 – Sep 4

* Data from USDA (2010)

Table G-2. Crop-specific dates used for PFAM modeling (Crop tab)

State Planting1 Emergence Date2 Release Date3 Harvesting1

AR April 22 May 2 September 3 September 24

CA May 13 May 23 September 17 October 8

LA April 14 April 24 August 4 August 25

MS May 2 May 12 August 30 September 20

TX April 9 April 19 July 31 August 21

1 Midpoint of dates provided in Table 1.

2 Assumed to occur 10 days after planting.

3 Assumed to occur 21 days before harvesting.

According to FPE labels, applications should occur at the 4-leaf stage to late tillering stage. 

According to the 2012 Arkansas Rice Quick Facts, pretillering (1st leaf to 4th leaf stage) occurs 

approximately 15-25 days after planting, while tillering can occur 24 to 42 days after planting. 

Based on this information, the first application is scheduled to occur 28 days after planting and 

the second application is scheduled to occur 14 days later (42 days after planting). Flood waters 

are released 60 days after the second application to allow for estimation of 21-day and 60-day 

average water concentrations for aquatic EECs. The third application is scheduled to occur 7 

days after harvest. Based on this information, the dates depicted in Table G-3 were used for 

modeling purposes.

Table G-3. Site-specific input dates used for PFAM modeling (Applications and Floods tabs), based in 

agronomic practices and labels

Scenario State App 1 App 2 Flood

(Event 1)

Release

(Event 2) App 3

0.071 lbs/A,

0.071 lbs/A (14 days after App 1)

0.046 lbs/A (7 days after harvest)

AR 5/20 6/3 4/23 8/2 10/1

CA 6/10 6/24 5/12 8/23 10/15

LA 5/12 5/26 4/13 7/25 9/1

MS 5/30 6/13 5/3 8/12 9/27

TX 5/7 5/21 4/10 7/20 8/28

0.108 lbs/A,

0.034 lbs/A (14 days after App 1)

0.046 lbs/A (7 days after harvest)

AR 5/20 6/3 4/23 8/2 10/1

CA 6/10 6/24 5/12 8/23 10/15

LA 5/12 5/26 4/13 7/25 9/1

Ms 5/30 6/13 5/3 8/12 9/27

TX 5/7 5/21 4/10 7/20 8/28

1. Release modeled 60 days after 2nd application. AR - dry seed. CA – water seed. LA – water seed, MS – dry 

seed, TX – dry seed
-Page 113 of 116-

For post-flood applications, FPE labels specify that the “water level should cover no more than 

25% of the annual grass weed foliage. The flood may be increased to a normal depth 2 to 3 days 

after application.” As such, fill levels were decreased to 1 inch (0.0254 m) the day prior to an 

application and were increased to 4 inches (0.1016 m) 2 days after application. Table G-4

provides additional information used in the PFAM modeling.

Table G-4. PFAM 1.05 inputs specific to FPE modeling runs

Input Parameter Value Source Comment

Chemical Tab

Water Column Half-life

(days) at 20°C 0.41

MRIDs 47123208, 

45081602 and 

48868701

Represents the 90th percent upper-bound 

confidence limit on the mean of 6 aerobic 

aquatic metabolism half-life values.1

Benthic Compartment 

Half-Life (days) at 20°C 2.7 MRIDs 45081601and 48868702

Represents the 90th percent upper-bound 

confidence limit on the mean of 3 anaerobic 

aquatic metabolism half-life values.

1

Unflooded Soil Half-life

(days) at 20°C 1.2 MRIDs 48757101 and 48868703

Represents the 90th percent upper-bound 

confidence limit on the mean of 4 aerobic soil 

metabolism half-life values.

1

Aqueous Near Surface

Half-life (days) at 40° 

Latitude

0.95 MRID 48098502

Hydrolysis Half-life

(days) 1x108 MRID 47123201 No evidence of degradation.

Organic Carbon Partition

Coefficient (mL/goc) (Koc)

165 MRID 42915001

Coefficient of variance for Kd data indicate 

more appropriate than Koc. Average of four Kd

values for TTR is 6.6 mL/g. Using the Foc value 

of 0.04 (Physical tab), a Koc value of 165 

mL/goc was used.

Molecular Weight (g/mol) 361.8 --- ---

Vapor Pressure (torr) 1.4E-08 Acc. # 412-03-0113 ---

Solubility (mg/L) 0.7 MRID 44676401

Heat of Henry (J/mol) 45727 ---

Estimated using HENRYWIN program in 

EPISuite

Henry Reference 

Temperature (oC) 20

Applications Tab

Number of Applications 3

Application dates See Table B-3

Mass applied See Table B-3

Slow release 0

Floods Tab

Number of Flood Events 6 ---

First event is flooding, second event is release 

of flood waters.

Date for Event 1 See Table B-3
-Page 114 of 116-

Input Parameter Value Source Comment

Event 

Number

Days 

after

Fill Level 

(m)

Weir 

Level (m)

Min 

Level 

(m)

Turn 

Over 

(1/day)

1 0 0.1016 0.1270 0.1016 0 Flood field

2 26/28 0.0254 0.0454 0.0254 0

Date of App1 minus 1 (26 for AR, MS, TX, 28 

for CA, LA)

3 29/31 0.1016 0.1270 0.1016 0

Date of App1 plus 2 (29 for AR, MS, TX, 31 

for CA, LA)

4 40/42 0.0254 0.0454 0.0254 Date of App2 minus 1 (40 for AR, MS, TX, 42 

for CA, LA)

5 43/45 0.1016 0.1270 0.1016 0

Date of App2 plus 2 (43 for AR, MS, TX, 45

for CA, LA)

6 101/103 0 0 0 0

Release 60 days after App 2 (101 for AR, MS, 

TX, 103 for CA, LA)

Crop Tab

Zero Height Reference

AR: 05/02

CA: 05/23

LA: 04/24

MS: 05/12

TX: 04/19

---

Emergence date, assumed to occur 10 days 

after planting. See Table 8 for dates.

Days from Zero Height to 

Full Height

AR: 124

CA: 118

LA: 102

MS: 111

TX: 103

---

Number of days from emergence to maturation. 

Maturation expected to occur 21 days prior to 

harvesting. See Table 8 for dates.

Days from Zero Height to 

Removal

AR: 145

CA: 139

LA: 123

MS: 132

TX: 124

---

Number of days from emergence to harvest. 

See Table 8 for dates.

Maximum Fractional 

Areal Coverage 1.0 --- Conservative assumption

Physical Tab

Weather file

AR (w13963)

LA (w13970)

CA (w23232)

MS (w03940)

TX (w13958)

---

Meteorological data available in PE5 

installation. Stations correspond to

Little Rock, AR (w13963), Baton Rouge, LA 

(w13970), Sacramento, CA (w23232), Jackson, 

MS (w03940), and Austin, TX (w13958)

Latitude 40 Default

Area of Application (m2)

4 345,600 ---

20% of the watershed drainage acreage 

(1,728,000 m2), based on draft HUC-8 PCA for 

rice

Weir leakage (m/d) 0 Default

Benthic leakage (m/d) 0 Default

Mass transfer coefficient 

(m/s) 1.0e-08 Default

Reference depth (m) 0.1270 Set to same depth as weir height, per PFAM 

guidance.

Benthic depth (m) 0.05 Default

Benthic porosity 0.50 Default

Dry bulk density (g/cm3) 1.35 Default

Foc water column on SS 0.04 Default
-Page 115 of 116-

Input Parameter Value Source Comment

Foc benthic 0.01 Default

SS (mg/L) 30 Default

Water column DOC

(mg/L) 5.0 Default

Chlorophyll CHL (mg/L) 0.005 Default

Dfac 1.19 Default

Q10 2 Default

1 EFED input parameter guidance is located at: : http://www.epa.gov/oppefed1/models/water/input_parameter_guidance.htm

2 4-inch paddy height assumed.
-Page 116 of 116-

Appendix H. ECOSAR Quantitative Structure-Activity Relationship (QSAR) Toxicity 

Predictions for FPE and Transformation Products.

In order to compare potential toxicity of FPE transformation products to the parent compound,

estimated toxicity data for FPE and transformation products were generated using quantitative 

structure-activity relationships (QSAR) derived in the program ECOSAR (version 1.11). 

ECOSAR is only used to explore relative toxicity among chemicals and is not used to derive 

endpoint values for estimating risk. ECOSAR estimates were compared to all available measured 

toxicity information for the parent and transformation products. These data are summarized in 

Table H-1. QSAR estimates for the parent compound were generally within an order of magnitude 

of empirical endpoints regardless of whether these estimates were based on a specific chemical 

class (i.e., esters) or baseline toxicity (i.e., neutral organics). None of the transformation products 

were placed in the same specific chemical class as the parent (i.e., esters) making a relative toxicity 

comparison difficult. However, based on the baseline toxicity category (i.e., neutral organics), all 

transformation products appear to be less toxic than the parent by at least a multiple of three. Since, 

this comparison is not based on a specific class or mode of action type, the evidence for lower 

toxicity of transformation products as compared to FPE is considered weak.

Table H-1. QSAR-Based Toxicity Estimates for FPE and Transformation Products

Compound 

(compounds class 

used by ECOSAR)

Estimated Toxicity Endpoint (mg/L)

96-hr 

FW Fish 

LC50

48-hr 

Daphnid 

LC50

96-hr 

Mysid 

LC50

96-hr EC50

Green 

Algae

FW Fish 

Chronic 

Value

Daphnid 

Chronic 

Value

Mysid 

Chronic 

Value

ECOSAR TOXICITY PREDICTIONS

Fenoxaprop-p-ethyl (Parent)

Empirical

(Measured)

0.46-0.58 >1.1 0.11 0.43 0.044 0.23 0.011

Esters 0.92* 1.4* 0.27 0.37 0.037 0.41 0.048

Neutral Organic SAR 0.67 0.50 NA 1.1* 0.09 0.10 NA

Fenoxaprop-p acid (AE F088406)

Empirical

(Measured)

>68.8 14.2->32 NA 44 1.8 0.34 NA

Neutral Organics 

Acid† 31 21 6.7 36 3.8 3.6 0.3

Chlorobenzoxazolone (AE F054014)

Empirical

(Measured)

>10 8.2 NA 7.5 NA NA NA

Carbamate Esters, 

Phenyl 5.8 0.029 NA 4.6 0.79 0.042 NA

Neutral Organic SAR 325 177 NA 113 30 16 NA

4-(6-chloro-2-benzoxazolyloxy)phenol (AE F040356)

Empirical

(Measured)

NA NA NA NA NA NA NA

Phenols 1.5 1.1 NA 4.2 0.21 0.21 NA

Neutral Organic SAR 3.9 2.6 NA 4.1 0.47 0.43 NA

NA = Empirical data or QSAR estimates are not available for specified group of organisms

* Predicted endpoint value exceeds estimated solubility limit for compound

† ECOSAR multiplies acid forms of compounds by a factor of 10