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Revised Ecological Risk Assessment for the Section 3 New Use

Registration of Tolfenpyrad

 

 

IUPAC Name: 4-Chloro-3-ethyl-1-methyl-N-[4-(p-tolyloxy)benzyl]pyrazole-5-carboxamide.

CAS Name: 4-Chloro-3-ethyl-1-methyl-N-[[4-(4-methylphenoxy)phenyl]methyl]-1Hpyrazole-5-carboxamide.

CAS Number: 129558-76-5.

U.S. EPA PC Code: 090111

DP Barcode: 408705

Team Members

Larry Liu, Fate Scientist

Brian Montague, Fishery Biologist

Peer Review

Justin Housenger, Biologist

Keith Sappington, Senior Science Advisor

Dr. Michael Barrett, Senior Fate Scientist

ERB5 Branch Chief 

Mah Shamim

Date of Approval 

N

N

H3C O

H N C

O

Cl

CH3

H3C
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Contents

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

2.0 Problem Formulation....................................................................................................................................8

2.1 Nature of Regulatory Action............................................................................................................................8

2.2 Stressor Source and Distribution ....................................................................................................................8

2.2.1 Mode of Action and Nature of the Chemical Stressor ............................................................8

2.3 Pesticide Use Characterization and Scope of the Potential Use Area ............................................................8

2.4 Receptors.......................................................................................................................................................11

2.4.1 Aquatic and Terrestrial Effects......................................................................................11

2.4.2 Ecosystems Potentially at Risk......................................................................................11

2.4.3 Ecological Effects.....................................................................................................12

2.5 Conceptual Model.....................................................................................................................12

2.5.1 Risk Hypotheses.......................................................................................................12

2.5.2 Conceptual Diagram................................................................................................13

2.6 Analysis Plan...........................................................................................................................15

2.6.1 Measures of Exposure and Effects.................................................................................15

2.6.2 Data Gaps..............................................................................................................17

3.0 Exposure Analysis .......................................................................................................................................22

3.1 Use characterization .....................................................................................................................................22

3. 2 Environmental Fate and Transport Characterization ..............................................................................22

3.2.1 Fate in water............................................................................................................26

3.2.2 Fate in air...............................................................................................................26

3.2.3 Field Studies...........................................................................................................26

3.2.4 Bioconcentration Studies.............................................................................................27

3.2.5 Fate Properties of Transformation Products.......................................................................27

3.3 Aquatic Exposure Estimates..........................................................................................................................29

3.3.1 Modeled Exposure in Surface Water and Pore Water............................................................30

3.3.2 Aquatic Exposure Monitoring and Field Data.....................................................................32

3.4 Terrestrial Wildlife Exposure Estimates........................................................................................................32

3.4.1 Inhalation Exposure...................................................................................................34

3.4.2 Dermal Exposure......................................................................................................34

3.4.3 Drinking Water Exposure............................................................................................34

3.4.4 Exposure of Piscivorous Wildlife...................................................................................35

3.5 Terrestrial and Semi-Aquatic Plant Exposure Estimates..............................................................................37

4.0 Ecological Effects Analysis ........................................................................................................................38

4.1 Aquatic Effects Summary...............................................................................................................................38

4.1.1 Toxic Effects to Fish..................................................................................................38

4.1.2 Toxic Effects to Aquatic Invertebrates.............................................................................41

4.1.3 Toxic Effects to Aquatic Vascular Plants and Algae.............................................................43

4.2 Terrestrial Effects Summary..........................................................................................................................44

4.2.1 Toxic Effects on Birds................................................................................................44

4.2.2 Toxic Effects on Mammals..........................................................................................46

4.2.3 Toxic Effects on Terrestrial Invertebrates.........................................................................48

4.2.4 Toxic Effects on Terrestrial Plants.................................................................................49
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4.5 Review of ECOTOX Data..............................................................................................................................50

4.6 Review of Incident Data ................................................................................................................................50

5.0 Risk Characterization .................................................................................................................................51

5.1 Risk Estimation Process: Integration of Exposure and Effects Data ............................................................51

5.1.1 Non-target Aquatic Fish, Invertebrates, and Plants...............................................................51

5.1.2 Non-target Terrestrial Animals (Terrestrial Diet).................................................................54

5.1.3 Non-target Terrestrial Animals (Aquatic Prey)...................................................................58

5.1.4 Terrestrial and Semi-aquatic Plants.................................................................................59

5.1.5 Non-Target Insect Pollinators.......................................................................................59

5.2 Risk Description ............................................................................................................................................61

5.2.1 Risks of Tolfenpyrad to Aquatic Organisms......................................................................61

5.2.2 Risks of Tolfenpyrad to Terrestrial Organisms...................................................................64

6.0 Description of Assumptions and Limitations............................................................................................68

6.1 Assumptions and Limitations Related to Exposure for all Taxa....................................................................68

6.2 Assumptions and Limitations Related to Exposure for Terrestrial Species...................................................68

6.3 Assumptions and Limitations Related to Exposure for Aquatic Species........................................................69

6.4 Assumptions and Limitations Related to Effects Assessment.........................................................................70

7.0 Literature Cited.........................................................................................................71

Appendix A. Summary of minor degradates formation from degradation of tolfenpyrad and the chemical 

structures

Appendix B. Proposed route of degradation of tolfenpyrad in aerobic soil system and minor degradate 

formation 

Appendix C. Model Descriptions/ Inputs/ Outputs

Appendix D. Risk Quotient Methods and Level-of-Concern Definitions

Appendix E. KABAM Bioaccumulation Assessment Results

Appendix F. Health Effects Division mammalian toxicity profile

Appendix G. ECOSAR results for tolfenpyrad and its major degradation products

Appendix H. Endangered Species Policy and Guidance Information
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1 Executive Summary

Nichino America is seeking new registrations for the active ingredient tolfenpyrad. These 

proposed registrations would be the first outdoor uses of the chemical (indoor greenhouse use is 

now registered). Nichino has made significant changes to the originally proposed 2012 label 

rates, removed aerial use on certain crops, and removed some crop uses with higher application 

rates. This current assessment is based on the 2013 revised labels for tolfenpyrad 15EC and 

tolfenpyrad 15SC. The proposed uses of tolfenpyrad for both products include citrus fruit (Crop 

Group 10), grapes (raisin, table, wine), apple, crabapple, loquat, mayhaw, quince, pear (oriental 

pear), leafy vegetables (Crop Group 4), cucurbit vegetables (Crop Group 9), potatoes, brassica 

(cole) leafy vegetables (Crop Group 5), fruiting vegetables (Crop Group 8 plus okra), cotton, 

stone fruit (Crop Group 12), tree nuts (Crop Group 14), and Ornamental greenhouse uses. 

Outdoor uses listed above consist of significant potential acreage exceeding 16 million acres 

(based 2007 USDA Agricultural Census).

Tolfenpyrad is a pyrazole insecticide proposed for use to control thrips, aphids and scales 

through the egg, larval, nymph, and adult stages. Tolfenpyrad has activity against several 

economically important insect pests of vegetable, fruits, nuts, vines, and row crops. It is active on 

Hemiptera, Thysanoptera, Lepidoptera, Coleoptera, Diptera, Orthoptera, Eriophid mites and 

Tarsonemid mites. It has activity on all development stages of target insects. Tolfenpyrad also 

has fungicidal activity against certain species of powdery mildew and downy mildews. 

The original ecological risk assessment was completed in 2012. In the 2012 risk assessment, 

EFED used a total toxic residue (TTR) method for surface water and pore water estimated 

environmental concentrations (EECs) that included tolfenpyrad and its four major degradates 

(PCA, PT-CA, PT(A)-4OH, and PAM). In early 2013, the registrant submitted two revised 

labels and four rainbow trout toxicity studies performed with these degradates. Findings in those 

four studies indicated that the degradates are much less toxic than the parent compound. Based 

on this data, a determination was made that only parent tolfenpyrad will be included in the 

current risk assessment of the proposed tolfenpyrad uses. 

Environmental Fate Profile

Tolfenpyrad and its transformation products are expected to undergo moderate degradation in the 

environment. In soil, tolfenpyrad is expected to be hardly mobile (with KOC 29,380). Two major 

acidic degradates detected in the soil and aquatic metabolism studies (PCA and PT-CA) are 

mobile, with KOC values of 12.5 and 19, respectively. Tolfenpyrad has the potential to 

contaminate surface water via spray drift and runoff of residues sorbed to sediment. The high 

octanol-water partition coefficient for tolfenpyrad (log KOW = 4.3-5.6) suggests a potential for 

bioaccumulation in aquatic food webs. Based on total radioactivity-based residues, the BCF in 

whole fish is 4,168, confirming its relatively high bioaccumulation potential. However, this BCF 

is lower than what would be predicted based on high KOW alone, which indicates tolfenpyrad is 

metabolized by fish to a significant extent. 
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It should be noted that tolfenpyrad was modeled in this assessment as relatively persistent if only 

one metabolism study type was available. If additional metabolism and mobility studies are 

available, EECs could be refined and may result in lower values. 

Ecological Toxicity Profile

Tolfenpyrad is classified as very highly toxic to freshwater fish (LC50 = 0.16 μg a.i./L) and 

aquatic invertebrates (EC50 = 1.0 μg a.i./L) on an acute exposure basis. It is also highly toxic to 

estuarine/marine fish (LC50 = 3.4 μg a.i./L) on an acute exposure basis. The formulated product 

showed similar toxicity as the TGAI to fish and aquatic invertebrates. The NOAEC for chronic 

effects on survival, growth and reproduction of freshwater and estuarine/marine fish occurred as 

low as 0.18 μg TRR/L. Chronic reproduction effects to freshwater invertebrates were observed at 

0.48 μg a.i./L with NOEC at 0.24 μg a.i./L. Toxicity to some algal species is also observed at 

low levels, with an acute EC50 of 1.0 μg a.i./L. However, toxicity to aquatic vascular plants was 

not observed at concentrations approaching the limit of solubility of tolfenpyrad in water. 

Importantly, recent data submitted on the acute toxicity of four degradates of tolfenpyrad (PAM, 

PCA, PT-CA and PT(A)-4OH) indicate the degradates are much less toxic than parent material 

to fish by at least three orders of magnitude.

With birds, tolfenpyrad is classified as moderately toxic on an acute oral exposure basis (LD50 = 

87 mg a.i./kg-bw) and slightly toxic on an acute dietary basis (LC50 = 1348 ppm in the diet). 

However, chronic effects to egg production observed in birds at 9.7 ppm and 24 ppm for mallard 

and bobwhite quail. Because adverse effects were observed at all treatment levels in these 

studies, the chronic avian NOAEC cannot be determined at this time. 

Tolfenpyrad is classified as moderately toxic to mammals on an acute exposure basis (LD50 = 

239 mg a.i./kg-bw) but displays much greater toxicity on a chronic exposure basis (NOAEC = 

0.86 mg a.i./kg-bw/d). It is also highly toxic to the honey bee, with an acute contact LD50 of 

0.47 ug a.i./bee and an acute oral LD50 of 0.63 ug a.i./bee. With terrestrial plants, EC25 values 

exceeded the maximum single application rate of 0.27 lb a.i./A. 

Ecological Risk Summary 

Based on newly estimated environmental concentrations, this screening-level risk assessment 

indicates that the proposed new uses of tolfenpyrad pose potential acute risks to fish, amphibians, 

freshwater invertebrates, birds, mammals and some species of algae (Table 1.1). The potential 

for chronic risks to freshwater and estuarine/marine fish, birds, terrestrial-phase amphibians, 

reptiles, and mammals is also evident based on the proposed label application rates and modeled 

exposure levels. High acute toxicity to honey bees indicates acute risk is possible to non-target 

pollinators from acute contact, direct ingestion of residues, or exposure to treated foliar surfaces. 

All proposed uses resulted in risk estimates that exceeded levels-of-concern for terrestrial and 

aquatic organisms, with the exception of vascular aquatic plants. Secondary risks are predicted 

for piscivorous mammals and birds.
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Table 1.1. Ecological risk estimation summary for tolfenpyrad

Taxon

Acute Risk Chronic Risk

Acute LOC 

Exceeded? 

(Yes/No)

(3)

Acute RQ 

Range

Chronic LOC 

Exceeded?

Yes/No(4)

Chronic RQ 

Range

Birds(1) Yes <0.01-2.5 Yes >0.6 - >14

Mammals Yes <0.01-0.25 Yes 0.4-70

Bees and other Insect 

Pollinators Yes 1.6-23 NA NA

Freshwater fish (2) Yes 0.7-17 Yes 0.05-3.6

Freshwater 

invertebrates Yes 0.1-2.7 Yes 0.04-2.9

Marine/estuarine fish Yes 0.03-0.83 Yes 0.05-2.5

Marine/estuarine 

invertebrates Yes <0.01 - <0.36 No 0.02-0.38

Aquatic plants NA NA Nonvascular – Yes

Vascular – No

0.1-5.6

<0.01-0.09

Terrestrial and semiaquatic plants –

monocots and dicots

NA NA

Dicots – No

Monocots - No

ND

(1) In absence of toxicity data, birds are used as a surrogate for reptiles and terrestrial-phase amphibians.

(2) In absence of toxicity data, freshwater fish are used as a surrogate for aquatic-phase amphibians.

(3) The acute LOC for listed and non-listed aquatic animals is 0.05 and 0.5, respectively.

(4) The chronic LOC for listed and non-listed aquatic and terrestrial animals is 1.0.

NA = not applicable; ND = not determined. RQ values that exceed the listed species LOC are shown in bold.

Data gaps

The following environmental fate data gaps have been identified, which if filled, could 

materially affect the risk assessment conclusions:

Aerobic Soil Metabolism (835.4100)

Since only one aerobic soil was selected from CA, the submitted study does not represent 

all the proposed use areas and its half-life was multiplied by three as a safety factor in 

modeling to account for expected variability. According to the proposed labels, 

tolfenpyrad can be used on citrus fruit, grapes, apple, crabapple, loquat, mayhaw, quince, 

pear, leafy vegetables, cucurbit vegetables, potatoes, brassica (cole) leafy vegetables, 

fruiting vegetables, cotton, stone fruit, tree nuts, and greenhouse. If the registrant would 

submit additional aerobic soil metabolism studies in which soil samples are collected 

from the proposed use areas, aquatic EECs could be lower. 

Fish Bioconcentration (850.1730)

The submitted fish bioconcentration study neither measured tolfenpyrad nor identified 

degradates in fish tissues, but shows a potential for bioconcentration of these chemicals

(BCF = 4,168 L/kg w.w. in whole fish) based on total radioactive residues in fish tissue 

and water. Although any in vivo biotransformation of tolfenpyrad by fish would result in 
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less parent material in fish tissue (and a lower BCF based on parent chemical), 

metabolism of the chemical in the exposure water would lead to a higher BCF based on 

parent chemical in water). Therefore, considering the high bioaccumulation potential of 

tolfenpyrad in fish, its persistence and the large spatial scale of its proposed use patterns, 

a new BCF study in which residues of parent chemical and metabolites are measured 

should be submitted to the Agency. 

Although an anaerobic aquatic metabolism (835.4400) study was submitted using only one 

water/sediment system, additional data are not being requested because such data would not 

likely alter the risk conclusions. Specifically, the existing anaerobic aquatic metabolism half life 

(385 days) was multiplied by 3X to address uncertainty associated with the availability of 

degradation rate information for less than two aquatic/sediment systems. Removal of this 3X 

factor would not materially affect the aquatic risk conclusions given that the existing half life is 

still very long (385 days). 

The following ecological toxicity data gaps have been identified, which if filled, could materially 

affect the risk conclusions:

Whole sediment toxicity, freshwater and estuarine/marine (/chronic). Based on the 

proposed use pattern and environmental fate properties of tolfenpyrad, it is expected to partition 

extensively to aquatic sediments. In consideration of its high toxicity to aquatic invertebrates, 

whole sediment toxicity data are needed to evaluate the potential for chronic toxicity to benthic 

invertebrate species. 

Avian reproduction test, upland gamebird and waterfowl species (850.2300). A chronic 

avian NOAEL was not determined but is estimated at < 9.7 ppm for mallard and < 24.3 ppm for 

bobwhite quail based on observed effects in these studies (MRIDs 48250428, 48250429, 

48250430, 48250431). There is need to determine the safe level of chronic exposure to birds for 

the purposes of accurately determining chronic risk to birds. 

Additional Exposure and Effects Data for Bees. The Tier 1 risk assessment indicates acute 

LOC are exceeded from both the diet and contact routes of exposure for honey bees. Since the 

Tier 1 risk assessment is based on conservative assumptions regarding exposure, additional data 

the residues of tolfenpyrad in pollen and nectar would help to refine the Tier 1 dietary risk 

assessment results. Such residue information can be obtained from field residue trials with the 

product applied to one or more crops in accordance with the label. Pending results of the refined 

Tier 1 assessment, results on the effects of tolfenpyrad on honey bees at the whole hive level 

may be needed. Alternatively, risk mitigation measures can be taken to avoid exposure of bees 

to tolfenpyrad, such as restricting applications during periods of bloom.
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2.0 Problem Formulation

2.1 Nature of Regulatory Action

The purpose of this assessment is to evaluate the environmental fate and ecological risks for the 

proposed new outdoor use registrations of the chemical tolfenpyrad and to evaluate the potential 

to cause unreasonable adverse effects to the environment, as required under the Federal 

Insecticide Fungicide and Rodenticide Act (FIFRA). Potential effects to Federal endangered and 

threatened wildlife and plants are also considered under the Endangered Species Act in order to 

ensure that the registration of tolfenpyrad is not likely to jeopardize such listed species or 

adversely modify their habitat. To these ends, this assessment follows U.S. EPA’s guidance on 

conducting ecological risk assessments and policies for assessing risk to non-target and listed 

organisms (U.S. EPA, 1998 and U.S. EPA, 2004).

The U.S. EPA pesticide registration process is a determination of whether a pesticidal product is 

eligible for registration and, if so, an enforceable description of how the pesticide may be used. 

A label represents the legal document which stipulates how and where a given pesticide may be 

used. End-use labels describe the formulation type, acceptable methods of application, where the 

product may be applied, and any restrictions on how applications may be conducted. Thus, 

potential use described by the propose pesticide labels is assessed.

2.2 Stressor Source and Distribution

2.2.1 Mode of Action and Nature of the Chemical Stressor

Tolfenpyrad is a pyrazole insecticide proposed for use to control thrips, aphids and scales 

through the egg, larval, nymph, and adult stages. It is also labeled for use as contact fungicide on 

the newest label. Tolfenpyrad impairs energy metabolism in the target pest. It works by 

inhibiting cellular respiration in the mitochondria. As a result, Tolfenpyrad causes rapid 

cessation of feeding and death of the pest usually within 24-48 hours. The chemical is classified 

as a Group 21A mitochondrial complex I electron transport inhibitor (METI) insecticide (IRAC, 

2011). See Section 3.2.1 for a summary of the chemistry and environmental fate data for 

tolfenpyrad.

2.3 Pesticide Use Characterization and Scope of the Potential Use Area

The proposed uses of tolfenpyrad include citrus fruit (Crop Group 10), grapes (raisin, table, 

wine), apple, crabapple, loquat, mayhaw, quince, pear (oriental pear), leafy vegetables (Crop 

Group 4), cucurbit vegetables (Crop Group 9), potatoes, brassica (cole) leafy vegetables (Crop 

Group 5), fruiting vegetables (Crop Group 8 plus okra), cotton, stone fruit (Crop Group 12), tree 

nuts (Crop Group 14), and ornamentals in greenhouses. The proposed use areas are found 

throughout the United States and are not limited to a particular geographic region. Since these 

are the first proposed outdoors uses of tolfenpyrad in the United States, no prior crop usage data 

is available. The proposed uses encompass a potential acreage of over 16 million acres based on 
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USDA 2007 Crop Census estimates. Cotton represents the largest portion of the crop acreage 

potential, followed by tree nuts, potato, grapes and citrus. This analysis may be revised when the 

new 2012 USDA census is completed. Many minor crops in these categories on the Tolfenpyrad 

labels were not covered individually in the census. Indoor greenhouse use is not included below.

Table 2.1 Major Crop Acreage Estimates Based on USDA 2007 Agricultural Census

Crop Group Major groups estimated by USDA* U.S. acreage totals

Citrus Limes, grapefruit, orange, lemon, tangerine 1,005,806

Cotton Cotton all states 10,493,238

Cucurbits Cucumber, honeydew, watermelon, pumpkin, 

squashes (all),cantaloupe, and other melons

541,161

Fruiting 

Vegetables

Tomatoes (all types), bell peppers, other peppers, 

eggplant, okra, and huckleberry

547,998

Brassica 

Vegetables

Broccoli, cabbage (all), brussel sprout, cauliflower, 

kale, mustard greens, and collards

281,209

Grapes (all) Raisin, table, and wine 1,051,047

Leafy Vegetables Celery, spinach, rhubarb, parsely, lettuce (head and 

leaf types)

392,658

Pome Fruit Apples, pears, other non-citrus 476,986

Potato Sweet and white potatoes 1,131,963

Stone Fruit Apricot, cherries(sweet & tart), nectarine, peach, 

plum, prune, pomegranate, and persimmon

483,126

Tree nuts Almond. chesnut, filberts, hickory, macadamia, pecan, 

pistachio, walnut, and others

1,857,179

This assessment includes the products Tolfenpyrad 15EC and Tolfenpyrad 15SC. Tolfenpyrad 

15EC is formulated as a 15% active ingredient emulsifiable concentrate (1.29 lb ai/gal) and also 

known as Hachi-Hachi® or Rycar®. Tolfenpyrad 15SC is formulated as a 15% active ingredient 

soluble concentrate (1.31 lb ai/gal) and is also called Torac®. Tolfenpyrad 15EC is currently 

registered for a greenhouse use only in the United States. 

According to the proposed labels, applications will be made using air, ground, airblast, air 

curtain and chemigation equipment. Table 2.2 contains the proposed use information, including 

single and seasonal application rates, maximum number of applications, etc. for each use. Rates 

of application for crops range from 0.14 to 0.27 lbs a.i./A in varying numbers of gallons of 

diluent. Rates of application for ornamental plants in greenhouse range from 0.20 to 0.31 lbs a.i. 

per 10,000 square feet. Use restrictions on the proposed label include a 150 feet buffer for aerial 

applications near fish-bearing aquatic habitats to protect endangered species. A 15-foot 

vegetative buffer between field edge and down-gradient aquatic habitats is also included on the 

proposed labels. Spray drift management provisions include avoiding aerial applications when 

wind speed is greater than 10 mph and during periods of temperature inversions. The use of 

tolfenpyrad in the state of New York is prohibited.
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Table 2.2 Revised New Uses of Tolfenpyrad (Formulations 15EC and 15SC).

Use Sites Application Method 

(Buffer Zone)

Single 

Application 

Rate (lb ai/A)

Maximum 

Applications 

per Season

Minimum 

Application 

Interval (days)

Maximum Seasonal 

Application Rate 

(lb ai/A)

Citrus fruit (Crop 

Group 10-10)

ground application 

or aerial application 

(with 150-ft buffer 

zone)

0.14-0.27 2

4 per year

14 0.54

Cotton ground application or 

aerial application

(west of MS river 

only, with 150-ft 

buffer zone)

0.14-0.21

2 14 0.42

Grapes (raisin, 

table, wine)

ground application 

only

0.14-0.27

2 14 0.41

Brassica (cole) 

leavy vegetables 

(Crop Group 5)

ground application or 

aerial application

(with 150-ft buffer 

zone)

0.14-0.21

2 14 0.42

Pome fruit (Crop 

Group 11-10)

ground application 

only 

0.14-0.27

2 14 0.41

Brassica (cole) 

leavy vegetables 

(Crop Group 5)

ground application or

aerial application 

(with 150-ft buffer 

zone)

0.14-0.21

2

4 per year

14 0.42

Leafy vegetables 

(except Brassica 

veg.)(Crop Group 

4)

ground application or

aerial application

west of MS river 

(with 150-ft buffer 

zone)

0.14-0.21

2

4 per year

14 0.42

Cucurbit 

vegetables (Crop 

Group 9)

ground application or 

aerial application 

west of MS river 

(with 150-ft buffer 

zone)

0.14-0.21 2

4 per year

14 0.42

Fruiting vegetables

(Crop Group 8-10)

ground application or 

aerial application 

west of MS river 

(with 150-ft buffer 

zone)

0.14-0.21 2

4 per year

14 0.42

Stone fruit (Crop 

Group 12)

ground appl.

0.14-0.27 2 14 0.54

Tree nuts (Crop 

Group 14)

ground appl.

0.14-0.27 2 14 0.54
Page 11 of 125 

Use Sites Application Method 

(Buffer Zone)

Single 

Application 

Rate (lb ai/A)

Maximum 

Applications 

per Season

Minimum 

Application 

Interval (days)

Maximum Seasonal 

Application Rate 

(lb ai/A)

Potatoes ground application 

or aerial application 

west of MS river

buffer zone not 

required)

0.14-0.21

2 14 0.42

Ornamental plants 

in greenhouse

ground appl. 0.20-0.31 lb 

ai/10,000 sq ft 2 10 0.62 lb ai/10,000 sq 

ft

Notes: 

1. Tolfenpyrad is not registered for use or sale in the state of New York. 

2. Labels state the maintenance of a minimum 15-foot wide vegetable filter strip for all crops.

3. Tolfenpyrad 15EC Insecticide (15% a.i.) EPA Reg No. 71711-31 (1.29 lb ai/gal); Tolfenpyrad 15SC Insecticide 

(15% a.i.) EPA Reg No. 71711-XX (1.31 lb ai/gal)

2.4 Receptors

2.4.1 Aquatic and Terrestrial Effects

The receptors are the biological organisms that are exposed to the chemical stressor (U.S. EPA, 

1998). Agency risk assessments use a surrogate species approach in evaluation of pesticides. 

Toxicological data generated from surrogate test species is intended to be representative of broad 

taxonomic groups and are used to extrapolate to potential effects on a variety of species.

Acute and chronic toxicity data includes studies submitted by pesticide registrants and/or 

available in open literature. This includes toxicity data on the technical grade active ingredient, 

degradates, and formulated products when available. 

Open literature studies are primarily identified through U.S. EPA’s publicly available ECOTOX 

database http://cfpub.epa.gov/ecotox/) literature search engine. The evaluation of unpublished 

registrant submissions and published sources of data may provide insight into the direct and 

indirect effects of tolfenpyrad on biotic communities from loss of species that are sensitive to the 

chemical and from changes in structure and functional characteristics of affected communities. 

2.4.2 Ecosystems Potentially at Risk

In general terms terrestrial ecosystems potentially at risk could include the treated field or 

orchards and areas immediately adjacent to the treated field or orchard that may receive drift or 

runoff. Terrestrial habitats adjacent to the treated area could include other cultivated fields, 

fencerows and hedgerows, meadows, fallow fields or grasslands, woodlands, riparian habitats 

and uncultivated areas. 

Freshwater aquatic ecosystems include water bodies adjacent to or downstream from the treated 

field including water bodies such as ponds, lakes, reservoirs, semi aquatic habitats such as 

marshes or ditches and flowing waterways such as streams or rivers. In coastal areas aquatic 

habitat may includes salt mashes, tidal rivers, irrigation canals and bogs.
Page 12 of 125 

2.4.3 Ecological Effects

Ecological measurement endpoints for this risk assessment would be based on toxicity 

information for tolfenpyrad in a suite of registrant-submitted toxicity studies and in the publicly 

available open literature including the ECOTOX database. 

With outdoor uses of conventional pesticides under FIFRA, registrant-submitted toxicity studies 

are generally required for organisms in the following broad groupings:

1. Birds (mallard duck or bobwhite quail and a passerine species): Birds are also used as a 

surrogate species for terrestrial-phase amphibians and reptiles

2. Freshwater fish (generally rainbow trout and bluegill sunfish): Fish values are used as a 

surrogate data for aquatic-phase amphibians if no amphibian data is available.

3. Freshwater invertebrates: (usually crustacea such as Daphnia sp.)

4. Estuarine/marine fish: (generally the sheepshead minnow)

5. Estuarine/marine invertebrates: (Mollusc and Crustacean usually Oyster or Mysid)

6. Terrestrial plants:(monocots and dicots – 10 species)

7. Aquatic plants: (vascular and non-vascular plants – 5 species)

8. Terrestrial Pollinator Insect: (honeybee)

9. Mammals: (laboratory rat are generally used as a surrogate for wild mammals) 

Within each of these very broad taxonomic groups, an acute and/or chronic endpoint is selected 

from the available test data if testing with those taxa are available. Data submitted for other 

taxonomic groups may be reviewed and considered as well. Data for metabolites of concern and 

certain formulations may also be required on a case by case basis.

2.5 Conceptual Model

A conceptual model provides a written description and visual representation of the predicted 

relationships between the potential routes of tolfenpyrad exposure and the predicted effects for 

the assessment endpoint. A conceptual model consists of two major components: risk hypotheses 

and a conceptual diagram (U.S. EPA, 1998).

2.5.1 Risk Hypotheses

For tolfenpyrad, the following ecological risk hypothesis is being employed for this risk 

assessment:

Given the widely proposed uses of tolfenpyrad and its environmental fate properties, 

there is a likelihood of exposure to non-target terrestrial and aquatic organisms. 

When used in accordance with the label, tolfenpyrad will result in potential adverse 

effects upon the survival, growth, and reproduction of non-target terrestrial and aquatic 

organisms. 
Page 13 of 125 

2.5.2 Conceptual Diagram

In order for a chemical to pose an ecological risk, it must reach habitats and organisms in 

biologically significant concentrations. An exposure pathway is the means by which a 

contaminant moves in the environment from the point of application to the effected organisms. 

Environmental transport medium must include a feasible route of exposure. In addition, the 

potential mechanisms of transport and transformation must be understood, especially for 

metabolites or degradates of toxicological concern. The assessment of ecological exposure 

pathways, therefore, includes an examination of the source, the potential migration pathways for 

the chemical, and the determination of potential exposure routes for the organisms exposed 

including ingestion, inhalation, direct contact and dermal absorption pathways. Figures 2-1 and 

2-2 represent conceptual models of exposure pathways for terrestrial organisms that may be 

potentially exposed to tolfenpyrad. Figure 2-3 contains the conceptual model for potential 

exposure of aquatic organisms to tolfenpyrad.

Figure 2-1. Conceptual diagram for tolfenpyrad effects on terrestrial organisms via 

commonly assessed exposure routes. Dotted lines indicate exposure pathways that have a low 

likelihood of contributing to ecological risk.

Stressor

Source

Receptors

Attribute

Change

Applications of Tolfenpyrad

Direct

application

Spray drift

Birds / Terrestrialphase amphibians / 

reptiles / mammals/ 

Insects

Juvenile

Adult

Terrestrial 

inverts

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in 

prey

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Terrestrial/riparian plants

grasses/forbs, fruit, seeds 

(trees, shrubs)

Runoff

Mammals

Exposure

Media

Soil

Ingestion

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

Root uptake

Wet/dry 

deposition

Birds / 

Amphibians

Ingestion
Page 14 of 125 

Stressor

Source

Attribute

Change

Pesticide applied to use site

Direct

application

Spray drift

Terrestrial 

vertebrates

Terrestrial 

invertebrates

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey and food

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related

to habitat

Runoff

Exposure Media Dew (formed on 

terrestrial plants)

Atmospheric 

transport

Receptors

Puddles (formed on 

treated fields)

Inhalation Ingestion

Air

Figure 2-2. Conceptual diagram for tolfenpyrad effects on terrestrial organisms via 

drinking water and inhalation. .

Figure 2-3. Conceptual diagram for tolfenpyrad exposure and effects on aquatic organisms. 

** Route of exposure includes only ingestion of fish and aquatic invertebrates

Stressor

Source

Receptors

Attribute

Change

Pesticide applied to use site

Spray drift

Aquatic animals

Invertebrates 

Vertebrates

**Piscivorous mammals 

and birds

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae and 

vascular plants

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Wet/dry deposition

Soil Leaching to

Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plants

terrestrial 

exposure 

pathways see 

Figure x
Page 15 of 125 

Mechanisms of release of tolfenpyrad based on current label applications are air, ground, 

airblast, air curtain and/or chemigation application of emulsifiable and suspension concentrate 

products. The conceptual model and subsequent analysis of exposure and effects are based on the 

parent tolfenpyrad. Though four degradates (PCA, PAM, PT-CA, and PT(A)-4OH) are expected

to be present, their low acute toxicity to fish indicates they will be of low initial concern for fish

within aquatic habitats. No data is available to characterize their potential to adversely affect

terrestrial vertebrates, aquatic invertebrates or aquatic and semi aquatic plants. However, for 

aquatic invertebrates and algae, ECOSAR estimates of toxicity suggest the degradates are 

substantially less toxic than the parent chemical (Appendix G).

Volatilization is not expected to be a significant route of dissipation for this chemical as the 

Henry’s Law constant for tolfenpyrad is 1.7x10-6atm•m3•mol-1. Concentrations of tolfenpyrad 

and its degradates, when sorbed to soil and transported to surface waters may be ecologically 

significant when runoff events occur or if off target spray drift after aerial or airblast application 

in close proximity to the treatment area occurs. Tolfenpyrad is not likely to leach to ground 

water whereas its acidic degradates (PCA and PT-CA) may leach to ground water. Based on its 

high hydrophobicity and BCF approximating 4000 L/kg w.w., the potential exists for 

bioaccumulation of tolfenpyrad in aquatic food webs and subsequent exposure to piscivorous 

wildlife.

2.6 Analysis Plan

This assessment characterizes the environmental fate and effects of tolfenpyrad and determines 

whether there is potential for risks to non-target organisms based on the proposed use patterns. In 

order to complete this process available environmental fate, ecotoxicity, and physicochemical 

property data were taken from studies submitted to the Agency. Studies were first reviewed to 

determine their acceptability relative to published U.S. EPA guidelines. 

The risk quotient approach used to estimate the potential for adverse effects on non-target 

terrestrial and aquatic organisms compares estimated exposure levels to laboratory-derived 

toxicity values. For the screening-level assessment of tolfenpyrad, the deterministic, risk 

quotient (RQ) method has been used to compare model estimated exposure with measured 

toxicity values. Estimated Environmental Concentrations (EECs) are divided by acute and 

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

(LOCs) (USEPA 2004a). These criteria are used to indicate if applications of tolfenpyrad, as 

directed on the label, will have the potential to cause adverse effects to non-target organisms by 

exceedance of these thresholds.

In the event that endpoints from submitted ecotoxicity studies are non-definitive, the Guidance 

for Using Non-Definitive Endpoints in Evaluating Risks to Listed and Non-listed Animal 

Species and the Guidance for Using Non-Definitive Endpoints in Evaluating Risks to Listed and 

Non-listed Plant Species will be consulted (U.S. EPA, 2011a and U.S. EPA, 2011b). 

2.6.1 Measures of Exposure and Effects 

Methods for Prediction of Exposure Levels
Page 16 of 125 

The proposed label application rates for the use of tolfenpyrad on representative food and nonfood crops were selected for modeling environmental concentrations for this base-level 

deterministic (risk-quotient based) assessment. The most sensitive toxicity endpoints from 

surrogate test species are used to estimate treatment-related effects on survival, growth, and 

reproduction. EECs used in the aquatic ecological risk assessment are based on the parent 

tolfenpyrad. Degradate testing produced much less toxic endpoints than the parent for freshwater 

fish (the most sensitive tested group for technical ai) and these estimated concentrations were not 

modeled.

For the aquatic assessment, EECs are produced by use of the latest version PRZM/EXAMS 

model.

Terrestrial exposure is estimated with the following models. More detailed explanations may be 

obtained in appendices or by web access at http://www.epa.gov/oppefed1/models/terrestrial/. 

Actual model runs and outputs are also included in the appendix C.

The T-REX model (Version 1.5.1) calculates the residues on avian and mammalian food items to 

estimate acute and chronic dietary exposure and risk. As a conservative approach, the modeled 

environmental exposure concentrations are the single-day maximum.

The TerrPlant model (version 1.2.2) provides screening level estimates of exposure to terrestrial 

plants from single pesticide applications. TerrPlant derives pesticide EECs in chemical drift and 

runoff. The model does not consider exposures to plants from multiple pesticide applications.

RQs are developed for non-listed and listed species of monocots and dicots inhabiting dry and 

semi-aquatic areas which are adjacent to pesticide treatment sites. 

The potential for inhalation risk to birds and mammals was assessed using the Screening Tool for 

Inhalation Risk (STIR, version 1.0, November 2010). 

Drinking water exposure potential for mammals or birds is predicted using Screening Imbibition 

Program (SIP 1.0, July 2010) using tolfenpyrad’s solubility and the highest application rate.

The KABAM model (KOW (based) Aquatic BioAccumulation Model) version 1.0 was used as the 

primary tool for evaluating the potential exposure and risk to birds and mammals that feed on 

aquatic organisms. This model will be applied in consideration of existing data on 

bioconcentration for tolfenpyrad and selected model parameters (e.g., in vivo metabolism rate or 

Km) may be adjusted to reflect current information.

Measures of Effect 

Table 2.2 lists the measures of environmental exposure and ecological effects used to assess the 

potential risks of tolfenpyrad to non-target organisms (U.S. EPA, 2004).
Page 17 of 125 

Table 2.2. Measures of Environmental Exposure and Ecological Effects Used to Assess the 

Potential Risks of Tolfenpyrad to Non-target Organisms

Assessment Endpoint Abundance (i.e., 

survival, reproduction, and growth) of 

individuals and communities 

Measures of Effect Measures of 

Exposure

birds, reptiles and terrestrial-phase amphibians Bobwhite quail/ mallard duck acute oral LD50

Bobwhite quail/ mallard duck sub-acute dietary 

LC50

Bobwhite quail/ mallard duck chronic 

reproduction NOAEC and LOAEC 

Maximum 

residues on food 

items (foliar) Survival, reproduction, and growth of 

individuals and populations of mammals 

Laboratory rat acute oral LD50

Laboratory rat 2-generation NOAEC and 

LOAEC

Freshwater fish and aquatic-phase amphibian 

- individuals and communities .

Acute Fish-Rainbow trout and bluegill sunfish 

LC50

Chronic - Freshwater Fish NOAEC and LOAEC

with Fathead minnow

Peak EEC

60-day average 

EEC

Freshwater invertebrate( individuals and 

communities)

Acute - Daphnid EC50 Peak EEC

Chronic -Daphnid life cycle NOAEC and 

LOAEC

21-day average 

EEC

Estuarine/marine fish and estuarine/marine 

invertebrate - individuals or communities

Acute Fish: Sheepshead minnow acute LC50

Acute Mollusc:Eastern oyster EC50

Acute Crustacean: Mysid LC50

Peak EEC

Chronic Fish Sheepshead NOAEC/LOAEC

Chronic Crustacean:Mysid NOAEC/LOAEC

60-day average 

EEC

21-day average 

EEC

Survival of beneficial insect populations Honeybee acute contact LD50 Hazard 

assessment only

Maintenance and growth of individuals and 

populations of terrestrial plants from standing 

crop or biomass

Monocot EC25 and NOAEC values for seedling 

emergence and vegetative vigor (survival and 

growth rate) 

Dicot EC25 and NOAEC values for seedling 

emergence and vegetative vigor (survival and 

growth rate) 

Estimates of 

runoff and spray 

drift to non-target 

areas

Maintenance and growth of individuals and 

populations of aquatic plants from standing 

crop or biomass

Vascular plant EC50 and NOAEC values for 

growth rate and biomass measurements

Non-vascular plant EC50 and NOAEC values for 

growth rate and biomass measurements 

Peak EEC

2.6.2 Data Gaps

Environmental Fate Data Requirements

With the exception of aerobic aquatic metabolism, only one soil or sediment system was 

included in each of the metabolism studies. In the absence of additional studies to better 

quantify the range in metabolism rates, EFED is multiplying the half-lives by 3X to provide a 

potential upper bound on the expected range in average metabolism half lives. According to the 

proposed labels, tolfenpyrad can be used over numerous crops as described in Table 1.1. The 
Page 18 of 125 

registrant should submit additional aerobic soil metabolism studies in which soil are collected 

from the proposed use areas.

The submitted fish bioconcentration study neither measured tolfenpyrad nor identified 

degradates in fish tissues, but shows a potential for bioconcentration of these chemicals (BCF = 

4,168 L/kg w.w. in whole fish) based on total radioactive residues in fish tissue and water. 

Although any in vivo biotransformation of tolfenpyrad by fish would result in less parent 

material in fish tissue (and a lower BCF based on parent chemical), metabolism of the chemical 

in the exposure water would lead to a higher BCF based on parent chemical in water). 

Therefore, given the bioaccumulation potential of tolfenpyrad in combination with its persistence 

and proposed use patterns, a new BCF study in which residues of parent chemical and 

metabolites are measured should be submitted to the Agency. 

 

Table 2.3. Environmental Fate Data Requirement for Tolfenpyrad.

Study Title Guideline MRID Study 

Classification

Additional Data Needed?

Hydrolysis 835.2120 47447713 Acceptable

No

Photodegradation in 

Water 835.2240 47463701 Acceptable

No

Photodegradation on Soil 835.2410 47447715 Acceptable No

Photodegradation in Air 835.2370 --- Waived

No

Aerobic Soil Metabolism 835.4100

47447716

48250406 

(amended report 

from 

47447716)

Acceptable

Yes. Studies using three 

additional soils are needed.

Anaerobic Soil 

Metabolism 835.4200

48250407

Acceptable

No

Aerobic Aquatic 

Metabolism 835.4300

48250408

48953811 Acceptable

No

Anaerobic Aquatic 

Metabolism 835.4400

48250409

Acceptable

No

Mobility - 

Adsorption/Desorption

835.1230 

47447712 

(parent)

48250404 (PCA 

and PT-CA)

Acceptable 

Acceptable for 

PT-CA study

Supplemental 

for PCA study

No

Terrestrial Field 

Dissipation (CA, FL, 

WA, MI)

835.6100 48250410 Acceptable No
Page 19 of 125 

Study Title Guideline MRID Study 

Classification

Additional Data Needed?

Fish Bioconcentration 850.1730 48250424 Supplemental

Yes. A study in which 

parent and its degradates 

are identified and 

quantified is needed.

ECM/ILV in soil 

835.6100

850.7100

48250454 

Analytical 

method in soil 

and storage 

stability analysis 

(parent, PCA, 

and PT-CA)

Acceptable 

No

48250456 

Analytical 

method (ILV) in 

soil (parent, 

PCA, and PTCA)

Acceptable

47447727 

Laboratory 

method analysis 

in soil (parent, 

PCA, and PTCA)

Acceptable

ECM/ILV in water 850.7100 48250443 

(parent) Acceptable

No

Ecological Effects Data Gaps

A summary of the submitted data and justification for additional data needed to fill ecological 

toxicity data gaps considered of high value to the risk assessment is provided in Table 2.4. 

Table 2.4 Ecotoxicity Data Requirements

Study Title Guideline MRID(s) Study 

Classification

Additional Data Needed?

Avian oral toxicity 850.2100

48250426 Supplemental

No. The acute oral study for passerine 

species is supplemental due to treatmentrelated regurgitation. The ED50 used for 

risk assessment was set based on 

regurgitation response, but no mortality or 

body weight changes occurred in birds 

regardless of regurgitation. Therefore, the 

ED50 is considered conservative. 

Furthermore, the oral LD50 for bobwhite 

quail (87 mg ai/kg bw) is close to the 

passerine ED50 (58 mg ai/kg bw); 

therefore, a substantial increase in the 

passerine LD50 above the current ED50

would not affect the risk conclusions 

47447722 Acceptable
Page 20 of 125 

Study Title Guideline MRID(s) Study 

Classification

Additional Data Needed?

because the bobwhite quail LD50 would be 

used for risk estimation.

Avian dietary toxicity 850.2200

47447723 Acceptable No

48250427 Acceptable

Avian reproduction 850.2300

48250428 

48250429 Supplemental Yes, a definitive NOAEL was not established in the available chronic avian 

toxicity studies conducted with 

Tolfenpyrad.

48250430 

48250431 Supplemental

Honeybee acute contact 

toxicity 850.3020 48250432 Acceptable No

Honeybee toxicity of 

residues on foliage 850.3030 48250433 Supplemental

No. The submitted toxicity of residues on 

foliage study for honey bees was classified 

as supplemental because an RT25 could 

not be determined. The mortality response 

observed in the study did not follow a 

dose-response pattern (40%, 13% and 

20% at 8, 24 and 48 hours, respectively). 

At 48 hours (test termination), mortality 

was high (20%) compared to the control 

mortality (5%). Therefore, the RT25 is 

likely between 8 and 48 hours.

Field Testing for 

Pollinators 850.3040

Yes, pending pollinator risk mitigation 

measures.

Freshwater fish –

acute toxicity 850.1075

47447721 Acceptable No.

48250415 Supplemental

48250413 Acceptable

48250416 Supplemental

47447719 Supplemental

47447720 Supplemental

48250417 Supplemental

Saltwater fish –

acute toxicity 850.1075 48250414 Acceptable No.

Freshwater 

invertebrates –

acute toxicity

850.1010

47490701 Acceptable No. One study was submitted that 

examined tolfenpyrad end-use product 

toxicity to freshwater invertebrates, but 

considered supplemental as concentrations 

were not measured.

47447718 

with 15 

EC

Supplemental

Saltwater invertebrates 

–acute toxicity

850.1025

850.1035

48250412 Supplemental

No. A definitive LC50 could not be 

calculated for the saltwater mysid or 

eastern oyster, due to lack of effects at the 

highest treatment level. However, the peak 

modeled surface water concentrations did 

not exceed the highest concentration tested 

in these studies

48250411 Supplemental

freshwater invertebrate 

life cycle test 850.1300 48250418 Acceptable No.
Page 21 of 125 

Study Title Guideline MRID(s) Study 

Classification

Additional Data Needed?

Saltwater 

invertebrates–

life cycle test

850.1350 48250420 Supplemental

No. The available study used a total 

radioactive residues to quantify 

tolfenpyrad exposure (the radioactivity 

was not assigned to either the parent 

compound or degradates). However, 

degradates are not considered of 

toxicological concern to aquatic 

organisms.

Freshwater fish –

early life stage test/life 

cycle test

850.1400

850.1500

48250422

48250423

Supplemental

Supplemental

No. Growth results from ELS test not 

considered reliable; Results from fish full 

life cycle study considered supplemental 

due to use of total radioactive residues 

instead of parent chemical

Saltwater fish –

early life stage test/life 

cycle test

850.1400

850.1500 48250421 Supplemental

No. The available study used a total 

radioactive residues to quantify 

tolfenpyrad exposure (the radioactivity 

was not assigned to either the parent 

compound or degradates). However, 

degradates are not considered of 

toxicological concern to aquatic 

organisms.

Whole sediment 

toxicity test, freshwater 

invertebrates

Whole sediment 

toxicity test, saltwater 

invertebrates

48250425 Supplemental

Yes. Although the LOAEC from this study 

was greater than the highest test 

concentration, the predicted pore water

exposure concentrations exceed the 

highest pore water concentration in this 

study. The high partitioning, toxicity and 

persistence of tolfenpyrad indicate that 

chronic (life cycle) sediment toxicity data 

are needed to assess risks to benthic 

aquatic invertebrates. 

Terrestrial Plant 

toxicity: Tiers I/II 

seedling emergence

850.4225 48250434 Supplemental

No.

Terrestrial Plant 

toxicity: Tiers I/II 

vegetative vigor

850.4250 48250435 Acceptable

No.

Aquatic Plant Growth: 

algae 850. 5400

47447725 Acceptable No

48250437 Supplemental

47447726 Supplemental

48250441 Supplemental

48250438 Supplemental

48250439 Supplemental

48250440 Supplemental

Aquatic Plant Growth: 

vascular plants 850.4400 48250436 Supplemental

No. The submitted tolfenpyrad toxicity 

study with the aquatic vascular plant 

species Lemna gibba did not allow 

calculation of a definitive EC50. However, 
Page 22 of 125 

Study Title Guideline MRID(s) Study 

Classification

Additional Data Needed?

no risk concerns were expected to this 

taxon using a more conservative estimate 

of toxicity, the available NOAEC from 

this study. Therefore, no additional data is 

requested at this time

Freshwater 

Invertebrate

life cycle test

850.1300 48250418 Acceptable

No.

Saltwater 

invertebrates–

life cycle test

850.1350 48250420 Supplemental

No. The available study used a TRR to 

quantify tolfenpyrad exposure (the 

radioactivity was not assigned to either the

parent compound or degradates). 

However, the degradates are not 

considered of toxicological concern to 

aquatic organisms. 

3.0 Exposure Analysis

3.1 Use characterization

See Section 2.3 for an overview of the proposed pesticide usage for this new use assessment.

3. 2 Environmental Fate and Transport Characterization 

Based on the submitted environmental fate data and reported physical-chemical properties, 

tolfenpyrad and its transformation products are expected to undergo moderate degradation in the 

environment. Tolfenpyrad has the potential to contaminate surface water via spray drift and 

runoff of residues sorbed to sediment. Since tolfenpyrad is currently proposed for use on many 

crops, deposition off-field or into surface water via spray drift is likely. 

In the laboratory, tolfenpyrad degraded to PAM, PCA, PT(A)-4OH, PT-CA, PT-CHO, PT-OH, 

OH-PAM, and OH-PT-OH in aqueous photolysis (linear half-life = 23.6 days, 12 hour light/dark 

cycle), soil photolysis (linear half-life = 48.1 days, 12 hour light/dark cycle), aerobic soil 

(nonlinear half-life = 15.1 days and IOR), anaerobic soil (nonlinear half-life = 216.6 days), 

aerobic aquatic (nonlinear half-life, total system = 14.5 days and IORE half-life, total system = 

5.1 days), and anaerobic aquatic (nonlinear half-life, total system = 385.1 days) conditions. 

Tolfenpyrad was essentially stable under laboratory hydrolysis conditions. Under terrestrial field 

conditions, tolfenpyrad degraded to PCA and PT-CA (tolfenpyrad nonlinear half-lives = 1.8-6.6 

days). PCA and PT-CA are expected to be mobile (KOC values of 12.5 and 19 mg/L, 

respectively). 

In an aerobic sandy loam soil environment in the laboratory, 20.7-51.7% of the applied 

tolfenpyrad was present at 21 days, decreasing to 1.6-2.8% at 365 days. In an anaerobic sandy 

loam soil environment in the laboratory, 27.7-54.4% of the applied was present almost 

exclusively in the soil at 44 days post-treatment (30-31 days post-flooding), decreasing to 11.6-
Page 23 of 125 

51.3% at 135-136 days post-treatment (122 days post-flooding). In an aerobic aquatic pond 

water-sandy loam sediment environment, 14.1-23.5% of the applied was present only in the 

sediment at 30 days, decreasing to 4.1-7.2% at 101 days post-treatment. In an aerobic aquatic 

lake water-sand sediment environment, tolfenpyrad in the water column decreased from 90.1-

100.5% of the applied at day 0 to 1.6-4.9% at 7 days and was not detected thereafter, while 

tolfenpyrad in the sediment increased from 7.0-9.4% of the applied at day 0 to a maximum 

60.4% at 3 days and was 1.5-1.9% at 100 days. In an anaerobic aquatic pond water-loam

sediment environment in the laboratory, 71.2% of the applied was present in the sediment only at 

33 days, decreasing to 48.9% at 367 days post-treatment. Tolfenpyrad is essentially stable to 

hydrolysis with 90.3-93.7% of the applied remaining after 31 days at pH 5, 7, and 9. Under field 

conditions it appears that a combination of processes takes place and that this chemical dissipates 

faster in the field than predicted by the available laboratory studies. Tolfenpyrad degrades and 

dissipates quickly and was detected up to 59 days in sand soil and not detected after 30, 7 and 31 

days in loam, sandy loam and loamy sand soils, respectively.

In soil, tolfenpyrad is expected to be hardly mobile. In four soils (sandy clay loam, sandy loam, 

clay loam and loamy sand), the adsorption soil-water partition coefficients (Kd) were 123-1,101 

mg/L, and the organic carbon partition coefficients (KOC) were 18,882-40,364 mg/Kgoc in the 

four soils with organic matter contents of 0.7-6.8% and pHs of 5.6-7.9. The octanol-water 

partition coefficient (log KOW) of tolfenpyrad was 4.3 (MRID 47447701). However, another 

much higher KOW of tolfenpyrad (log KOW 5.61) was reported in a field dissipation study (MRID 

48250410). As requested, the registrant had submitted this study to OPP in 2012 (MRID 

48953811). 

Tolfenpyrad moderately degrades under aerobic conditions (half-lives of 14-15 days in aerobic 

soil and aerobic aquatic water-sediment systems, and dissipation half-lives of 1.8-6.6 days under 

terrestrial field conditions). Under anaerobic conditions, tolfenpyrad is considerably more 

persistent (half-life 216.6 days in anaerobic soil and 385.1 days in anaerobic aquatic watersediment system). The compound is relatively involatile (vapor pressure 3 x 10-7 mmHg) and 

essentially hardly mobile in soil. Therefore, it is not expected to leach to ground water. Due to 

the low KOC values, PCA and PT-CA may leach to ground water.

Tolfenpyrad degrades to PT(A)-4OH; and via cleavage of the tolyloxy group at the N-C bond to 

PAM, which is oxidized to PCA; and via oxidation of the terminal methyl group of the tolyloxy 

ring to form PT-OH, which is further oxidized to PT-CHO and PT-CA (see Appendix B for the 

proposed metabolism pathway). Tolfenpyrad ultimately degrades to CO2 and bound residues 

under all conditions. Table 3.1 summarizes the chemical and environmental fate data for 

tolfenpyrad. These were derived from information submitted under environmental fate 

guidelines. Hydrolysis, aqueous and soil photolysis, aerobic and anaerobic soil metabolism, 

aerobic and anaerobic aquatic metabolism, adsorption-desorption and terrestrial field dissipation 

studies were conducted with tolfenpyrad. 
Page 24 of 125 

Table 3.1. Summary of physical/chemical and environmental fate and transport properties 

of tolfenpyrad and its transformation products.

Parameter Value (S) (units) MRID CommentA

 Chemical Name Tolfenpyrad:

IUPAC: 4-Chloro-3-ethyl-1-methyl-N-[4-(ptolyloxy)benzyl]pyrazole-5-carboxamide.

CAS: 4-Chloro-3-ethyl-1-methyl-N-[[4-(4-

methylphenoxy)phenyl]methyl]-1H-pyrazole-5-

carboxamide.

PAM:

IUPAC: 4-Chloro-3-ethyl-1-methyl-1Hpyrazole-5-carboxamide.

PT-CA (Tolfenpyrad-PT-CA):

4-[4-({[(4-Chloro-3-ethyl-1-methyl-1H-pyrazol5-yl)carbonyl]amino}methyl)phenoxy]benzoic 

acid.

OH-PAM: 

4-Chloro-3-(1-hydroxyethyl)-1-methyl-1Hpyrazole-5-carboxamide.

PT-OH:

4-Chloro-3-ethyl-N-{4-[4-

(hydroxymethyl)phenoxy]benzyl}-1-methyl-1Hpyrazole-5-carboxamide.

PT-CHO:

4-Chloro-3-ethyl-N-[4-(4-

formylphenoxy)benzyl]-1-methyl-1H-pyrazole5-carboxamide.

PCA (Tolfenpyrad-PCA):

4-Chloro-3-ethyl-1-methyl-1H-pyrazole-5-

carboxylic acid.

PT(A)-4OH (PT(A)-4-OH):

4-Chloro-3-ethyl-N-(4-hydroxybenzyl)-1-

methyl-1H-pyrazole-5-carboxamide.

Product 

chemistry 

–

 Molecular Weight Tolfenpyrad: 385.7 g/mole

PT-CA: 413.9 g/mole

PCA: 118.6 g/mole

Product 

chemistry

–

 Solubility

 (25oC)

Tolfenpyrad: 0.087 mg/L in water

6.92 g/L in n-heptane

218 g/L in xylene

>250 g/L in 1,2-dichloroethane

50.8 g/L in methanol

43.7 g/L in n-octanol

250 g/L in acetone and ethyl acetate

368 g/L in acetone

Product 

chemistry 

-

 Vapor Pressure

 (25oC)

Tolfenpyrad: 

3 x 10-7 mmHg

Product 

chemistry

–
Page 25 of 125 

Parameter Value (S) (units) MRID CommentA

 Henry’s Law

 Constant (25oC)

1.7x10-6atm•m3•mol-1Product 

chemistry

Estimated from water 

solubility and vapor 

pressure

 pKa – – –

Octanol-Water

Partition Coefficient 

(log KOW, 25oC)

Tolfenpyrad:

4.3

5.61

47447705

48250410

48747601

-

pH not reported-

 Hydrolysis HalfLife (25oC)

 pH 5

 pH 7

 pH 9

Tolfenpyrad:

t1/2 = 3,465 days 

t1/2 = 693.1 days

Stable

47447713 Pyrazole label. At pH 5 

and 7, the half-lives were 

extrapolated beyond the 

duration of the study.

 Aqueous

 Photolysis Half-life 

 (pH 7 buffer, 25oC)

Tolfenpyrad:

t1/2 = 9.6 days (combined labels; continuous 

irradiation)

or

t1/2 = 23.6 days (combined labels; environmental 

12 hour light/dark cycle)

47463701 Pyrazole and tolyloxy 

labels. Tolfenpyrad was 

stable in dark controls 

 Soil Photolysis

 Half-life

 (25oC)

Tolfenpyrad:

t1/2 = 22.2 days (combined labels; continuous 

irradiation)

or

t1/2 = 48.1 days (combined labels; environmental 

12 hour light/dark cycle)

47447715

Pyrazole and tolyloxy 

labels. Tolfenpyrad was 

stable in the pyrazole label 

control, and declined in 

the tolyloxy label

. 

 Aerobic Soil

 Metabolism 

 Half-life (25oC,

75% of 1/3 bar)

Tolfenpyrad:

t1/2 = 15.1 days (combined labels; non-linear). 47447716

48250406

Pyrazole and tolyloxy 

labels. Sandy loam soil 

from California. 

 Anaerobic Soil

 Metabolism

Tolfenpyrad:

t1/2 = 216.6 days (combined labels; total system, 

non-linear).

48250407

Pyrazole and tolyloxy 

labels. Sandy loam soil 

from California. 

 Aerobic Aquatic

 Metabolism Tolfenpyrad:

t1/2 = 14.5 days (combined labels; total system, 

non-linear).

t1/2 = 5.5 days (combined labels; total system, 

non-linear).

48250408

48953811

Pyrazole and tolyloxy 

labels. Pond water-sandy 

loam sediment from 

California.

Pyrazole and tolyloxy 

labels. Pond water-sandy 

sediment from North 

Dakoda.

 Anaerobic Aquatic

 Metabolism

Tolfenpyrad:

t1/2 = 385.1 days (pyrazole label; total system, 

non-linear).

48250409

Pyrazole labels. Pond 

water-loam sediment from 

California.

 Adsorption Tolfenpyrad KOC = 29,380 L/kgOC

(mean of 18882, 40364, 27525, and 30750)

PT-CA KOC = 19 L/KgOC

PCA KOC = 12.5 L/KgOC

47447712

48250404

Two soils (clay loam and 

sandy loam) for PCA 

study. Four soils (clay 

loam, two sandy loam, 

and sandy clay loam) for 

PT-CA study
Page 26 of 125 

Parameter Value (S) (units) MRID CommentA

 Terrestrial Field

 Dissipation Tolfenpyrad:

t1/2 = 1.8-6.6 days (four soils, non-linear). 48250410

Sand soil from Florida, 

loam soil from Michigan, 

sandy loam from 

California, and loamy soil 

from Washington

Fish 

Bioconcentration

Maximum BCFs in two test concentrations 

(0.015 and 0.045 ppm):

BCF in edible = 2,119x and 1,973x

BCF in nonedible = 6,948x and 7,227x

BCF in whole fish = 4,167x and 4,168x

48250424

Pyrazole labels. Well 

water from MD was used. 

Bluegill was used.

Studies conducted with both pyrazole and tolyloxy radiolabels include: aqueous photolysis, soil 

photolysis, aerobic and anaerobic soil metabolism, and aerobic and anaerobic aquatic 

metabolism. Studies conducted with pyrazole radiolabel only include hydrolysis, adsorptiondesorption, and fish bioconcentration.

3.2.1 Fate in water

Tolfenpyrad may enter surface water through spray drift when applied using a ground spray or 

aerial spray in an open air environment (currently approved for greenhouse use only), or in 

particularly adverse conditions through runoff of sediment bound residues (erosion) from 

agricultural fields. If it does reach surface water, tolfenpyrad is expected to be slow to degrade 

to PAM, PT-CA, PT-OH, and PT-CHO under ideal conditions for photodegradation. In the 

absence of sunlight, tolfenpyrad is stable to hydrolysis. Being hardly mobile, tolfenpyrad is not 

expected to leach to ground water. Due to the low KOC values, PCA and PT-CA may leach to 

ground water.

3.2.2 Fate in air

Based on its low vapor pressure (4 x 10-5Pa at 25°C), tolfenpyrad is not likely to partition 

significantly to air. Volatile products other than CO2 were not detected in volatile traps in the 

laboratory studies; the majority of the applied radioactivity was recovered in the soil. At 

environmentally relevant pH ranges, tolfenpyrad is not likely to vaporize from soil or water at a 

significant level. Some movement of bound residues on wind-borne soil particles is a possibility. 

However, long-range transport in air is not likely to be a dissipation route of concern for 

tolfenpyrad.

3.2.3 Field Studies

Four terrestrial field dissipation studies for tolfenpyrad were provided. Half-lives ranged from 

1.8-6.6 days. PT-CA and PCA were detected 0-15 cm soil depths. PCA was also detected 15-30 

cm soil depths.
Page 27 of 125 

3.2.4 Bioconcentration Studies

A bioconcentration in fish study for tolfenpyrad was provided. The test species was bluegill 

sunfish. However fish samples and exposure water were analyzed for total radioactive residues 

only and concentrations of tolfenpyrad in the fish samples and exposure water were not 

determined. However, tolfenpyrad is stable to hydrolysis and under laboratory aqueous 

photolysis (12 hour light/dark cycle) has a half-life of 23.6 days, therefore, the radioactive 

residues present in the exposure water are likely to be tolfenpyrad. Steady-state BCF values 

were 1,577 for edible tissues, 4,959 for nonedible tissues, and 3,008 for whole fish tissues for 

total residues. Maximum BCF values were 1,973 (28 days) for edible tissues, 7,227 (28 days) for 

nonedible tissues, and 4,168 (28 days) for whole fish tissues, based on total residues. Uptake 

rate constants (k1) were 294, 1,243, and 680 days-1and depuration rate constants (k2) were 0.209, 

0.235, and 0.224 days-1for edible, nonedible, and whole fish tissues, respectively. 

3.2.5 Fate Properties of Transformation Products

The major transformation products (formed in amounts greater than or equal to 10% of applied 

radioactivity) resulting from the degradation of tolfenpyrad are: PAM (aqueous and soil 

photolysis, aerobic aquatic metabolism), PCA (tolfenpyrad-PCA; aerobic soil and aerobic 

aquatic metabolism and terrestrial field dissipation), PT-OH (aqueous photolysis), PT-CHO

(aqueous photolysis), PT(A)-4OH (anaerobic soil) and PT-CA (tolfenpyrad PT-CA; soil 

photolysis, aerobic and anaerobic soil metabolism, aerobic and anaerobic aquatic metabolism 

and terrestrial field dissipation) (Table 3.2). Although some of the degradates described above 

as major degradates detected in some studies, some of these major degradates could be detected 

as minor degradates in other studies. In addition, two minor degradates were detected (see 

Appendix A for minor degradates and the chemical structures for all identified degradates).

The identified minor transformation products (formed in amounts less than 10% of applied 

radioactivity) resulting from degradation of tolfenpyrad under laboratory conditions are: PAM

(aqueous and soil photolysis, dark control, aerobic and anaerobic soil, and anaerobic aquatic), 

PT-OH (aqueous and soil photolysis, aerobic soil), PT-CHO (soil photolysis), PT-CA (aqueous 

and soil photolysis), OH-PAM (soil photolysis), PCA (anaerobic soil and anaerobic aquatic), 

OH-PT-OH (anaerobic soil and aerobic aquatic water-sediment) and PT(A)-4OH (aerobic soil 

and anaerobic aquatic) (Table 3.9).

 

The degradates PCA and PT-CA are expected to be highly mobile. For PCA in two soils (clay 

loam and sandy loam) and PT-CA in four soils (clay loam, sandy loam, sandy loam, and sandy 

clay loam), the adsorption soil-water partition coefficients (Kd) were 0.11-0.49 and 0.01-2.00 

mg/L, respectively. The octanol-water partition coefficient (log KOW) and pH of PCA and PTCA were not reported. The Freundlich adsorption coefficients (KOC) of PCA were 6-9 (PT-CA 

not determined) in two soils with organic matter contents of 1.9-5.6% and pHs of 5.5-5.7 (1:1, 

soil:water ratio). PCA and PT-CA are classified as highly mobile (FAO 2000).
Page 28 of 125 

Table 3.2. Summary of major degradate formation from degradation of Tolfenpyrad. 

STUDY TYPE MAJOR DEGRADATE and MAXIMUM CONCENTRATION SOURCE

MRID

PAM (% applied) PT-CA (% 

applied)

PCA (% applied) PT-CHO (% 

applied)

PT-OH (% 

applied)

PT(A)-4OH (% 

applied)

Batch 

Equilibrium

– –

– – – –

–

Hydrolysis – – – – – – 47447713

Aqueous 

Photolysis

10.8% at 307.5 

hours (irradiated 

pyrazole label)

– – 9.7% at 102 hours 

(irradiated 

pyrazole label)

10% at 143 hours 

(irradiated 

tolyloxy label)

9.3% at 318 hours 

(7.1% and 11.5% 

in the replicates 

;irradiated 

tolyloxy label)

– 47463701

Soil Photolysis 11.3% at 310.3 

hours (irradiated 

pyrazole label)

13% at 313.5 

hours (irradiated 

tolyloxy label)

– – – –

47447715

Aerobic Soil 

Metabolism

– 36.9% at 30 days 

(tolyloxy label)

34% at 63 days 

(pyrazole label) – – –

47447716

48250406

Anaerobic Soil

Metabolism

– 41.6% at 44 days, 

total system 

(pyrazole label)

– – –

20.4% at 136 

days, total system, 

(pyrazole label)

48250407

Anaerobic 

Aquatic 

Metabolism

– 18.0% at 90 days, 

total system 

(pyrazole label)

– – – – 48250409

Aerobic Aquatic 

Metabolism

11.8% at 30 days, 

total system 

(pyrazole label)

50.1% at 30 days, 

total system 

(tolyloxy label)

48.9% at 101 

days, total system 

(pyrazole label)

– – – 48250408

Aerobic Aquatic 

Metabolism

16.1% at 30 days, 

total system 

(pyrazole label)

50.3% at 7 days, 

total system 

(pyrazole label)

64.3% at 100 

days, total system 

(pyrazole label)

- - - 48953811

Terrestrial Field 

Dissipation

– detected at 14 

days in loamy 

sand soil

detected at 13 

days in sandy 

loam soil

– – – 4825410

Studies conducted with both pyrazole and tolyloxy radiolabels include: aqueous photolysis, soil photolysis, aerobic and anaerobic soil 

metabolism, aerobic and anaerobic aquatic metabolism and terrestrial field dissipation. Studies conducted with pyrazole radiolabel only include 

hydrolysis and adsorption-desorption. The non-guideline analytical methods study was not radiolabelled. 

Tolfenpyrad degrades to PAM (see the aerobic soil metabolism pathway in Appendix B) via 

cleavage of the tolyloxy group at the N-C bond. PAM is formed at maximums of 10.8% of 

applied in aqueous photolysis, 11.3% in soil photolysis, and 11.8% in aerobic aquatic 

metabolism. PAM further oxidizes to PCA at a maximum of 34.0% of applied in aerobic soil, 

48.9% in aerobic aquatic water-sediment, and 19.8% in terrestrial field dissipation study. 

Tolfenpyrad also degrades via oxidation of the terminal methyl group of the tolyloxy ring to 

form PT-OH at a maximum average of 9.3% of applied in aqueous photolysis, which is further 

oxidized to PT-CHO at a maximum of 10.0% of applied in aqueous photolysis and PT-CA at 

maximums of 13.0% of applied in soil photolysis, 36.9% of applied in aerobic soil, 41.6% in 

anaerobic soil (total system), 50.1% in aerobic aquatic water-sediment (total system), 18.0% in 

anaerobic aquatic water-sediment (total system), and 26.6% in terrestrial field dissipation study. 

PT(A)-4(OH) is also formed via hydrolytic cleavage of the phenyl group in the tolyloxy moiety 
Page 29 of 125 

at maximums of 20.4% in anaerobic soil (total system), and 7.8% in anaerobic aquatic watersediment (total system). Tolfenpyrad ultimately degrades to CO2 and transforms to bound 

residues.

The degradation of tolfenpyrad to PAM, and also to PT-OH and PT-CHO, via aqueous 

photolysis is only likely to be significant in clear, shallow water. In actual environmental 

systems, aqueous photolysis is likely to proceed at a much slower rate due to the attenuation of 

light due to increasing depth of water bodies, light adsorption by suspended solids, and natural 

obstruction of sunlight. The remaining minor transformation products, OH-PAM and PT(A)-

4OH, are not expected to form in high concentrations in the environment.

Major Degradates

Major environmental degradates of a compound may be of exposure concern for surface water. 

The major transformation products resulting from the degradation of tolfenpyrad are: PAM, 

PCA, PT-OH, PT-CHO, PT(A)-4OH and PT-CA. Of these six major degradates, EFED is more 

concerned about PCA, PT-CA, PT(A)-4OH, and PAM due to their high residue levels and 

because PT-CHO and PT-OH were only formed via aqueous photolysis, which is not likely to be 

the dominant route of degradation. These degradates of exposure concern were identified to help 

the ROCKS determine which of them are of risk (rather than exposure) concern. At the ROCKS 

meeting, the team decided to include tolfenpyrad and its four major degradates (PCA, PT-CA, 

PT(A)-4OH, and PAM) as residues of concern in drinking water due to the lack of toxicity 

information. Total residues approach was used to estimate exposure to the tolfenpyrad residues 

of concern in drinking water. This approach involves the use of total-residues degradation halflives based on the sum of residues of concern at each sampling interval in submitted laboratory 

degradation studies. Also, the chemical properties and soil mobility of the residue of concern 

most vulnerable to environmental transport are typically used to represent the chemical 

properties and soil mobility of all residues. 

After the completion of the 2012 Tofenpyrad Ecological Risk Assessment (D383821), the 

registrant submitted additional rainbow trout toxicity studies. These studies produced toxicity 

values over 4000 times lower than the parent for this species. Based on the findings in these 

studies, EFED has decided to use parent compound only in modeling in the current ecological 

risk assessment.

3.3 Aquatic Exposure Estimates 

The Tier II models, Pesticide Root Zone Model (PRZM v3.12.2, May 12, 2005) linked with 

EXposure Analysis Modeling System (EXAMS v2.98.04.06, Apr. 25, 2005) via the PE model 

shell (PE v5.0, Nov. 15, 2006, i.e., PRZM/EXAMS) were run to estimate screening-level 

exposure of surface water sources to tolfenpyrad residues following the proposed uses. For 

those crops required a buffer zone of 150 feet in aerial application, AGDRIFT was used to 

estimate the spray drift prior to PRZM/EXAMS.

The PE model generates EECs of tolfenpyrad residues that may occur in surface water down 

gradient from applications on terrestrial crops. The PRZM model simulates pesticide movement 
Page 30 of 125 

and transformation from crop application through soil residue processes. The EXAMS model 

simulates pesticide loading via runoff, erosion, and spray drift assuming a standard watershed of 

172.8 ha that drains into an adjacent pond. EXAMS (PE) model and associated users manuals 

may be downloaded from the U.S. Environmental Protection Agency (EPA) Water Models webpage (http://www.epa.gov/oppefed1/models/water/index.htm ).

3.3.1 Modeled Exposure in Surface Water and Pore Water 

In order to assess the impact of the use of tolfenpyrad on the resulting EECs, the application 

inputs for representative food use in modeling were selected (Table 3.3). Since only one 

aerobic soil metabolism study and one anaerobic aquatic metabolism study were submitted, the 

metabolic half-lives used in modeling were timed by 3.

Table 3.3. PRZM/EXAMS Chemical Input Parameters for Tolfenpyrad. 

Input Parameter Value Justification Source

Molecular Weight (g/mol) 385.7 - Product Chemistry

Solubility in Water (mg/L) 0.087 - Product Chemistry

Vapor Pressure (mmHg) 3 x 10-7 - Product Chemistry

Hydrolysis Half-life at pH 7 

(days) 693 - 47447713

Aqueous Photolysis

Half-life (days) 25.6 Linear half-life 47447715

Organic Carbon Partition 

Coefficient (L/kg) 29,380 Mean of 18,882, 40,364, 27,525, and 30,750 47447712

Aerobic Soil Metabolism 

Half-life (days) 45.3 (15.1x3) Non-linear half-life 47447716

48250406

Aerobic Aquatic Metabolism 

Half-life (days) 24.3 Non-linear half-life 4825040848952801

Anaerobic Aquatic 

Metabolism Half-life (days)

1,155.3

(385.1x3) Non-linear half-life 48250409

The current ecological risk assessment is based on tolfenpyrad. Based on the revised labels 

(such as including a 150-ft buffer zone for aerial application, additional modeling was performed 

using the same approach on all representative food uses as well as all application methods. 

Tables 3.4 and 3.5 showed EECs in surface water and pore water, respectively. Tolfenpyrad 

was modeled in this assessment as relatively persistent because of limited number of aerobic soil 

and anaerobic aquatic metabolism studies are available. If additional fate studies are available, 

EECs could be refined and would likely result in lower values. 

Table 3.4. EECs (μg a.i./L) for surface water based on tolfenpyrad use patterns, 

application methods (aerial, ground, and airblast equipment) 

Scenario* Peak EEC 21-Day EEC 60-Day EEC

Aerial Application

CA citrus 0.21 0.07 0.05
Page 31 of 125 

Scenario* Peak EEC 21-Day EEC 60-Day EEC

FL citrus 0.78 0.26 0.22

TX cotton 2.68 0.67 0.47

CA cotton 0.20 0.08 0.02

CA tomatoes 0.17 0.17 0.04

CA lettuce 0.11 0.11 0.08

Fl cabbage 0.79 0.04 0.02

ID potato 0.31 0.11 0.09

Airblast Application

NC apple 1.62 0.55 0.41

PA apple 1.24 0.47 0.41

OR apple 0.85 0.36 0.28

CA citrus 0.48 0.15 0.01

FL citrus 0.19 0.32 0.28

GA peach 0.14 0.32 0.22

GA Pecans 1.44 0.40 0.31

Ground Boom, Air Curtain Sprayers or other application method

MS Cotton 2.80 0.88 0.67

FL cucumber 0.55 0.18 0.15

CA Tomato 0.13 0.04 0.03

CA Grapes 0.17 0.06 0.04

FL Cabbage 0.78 0.11 0.13

CA Lettuce 0.21 0.09 0.08

ID potato 0.30 0.10 0.08

* See Table 2.2 for application rate information and Table 3.3 for input parameters used to generate the aquatic 

EECs. Aquatic EECs for all aerial applications except potato include a 150 ft spray drift buffer per the proposed 

label.

Table 3.5. EECs (μg a.i./L) for Pore Water Based on Tolfenpyrad Use patterns, 

Application Methods (aerial, ground, and airblast equipment) 

Scenario* Peak EEC 21-Day EEC 60-Day EEC

Aerial Application

CA citrus 0.03 0.03 0.03

FL citrus 0.16 0.16 0.16

TX cotton 0.31 0.31 0.31

CA cotton 0.04 0.04 0.04

CA tomatoes 0.03 0.02 0.02

CA lettuce 0.06 0.06 0.06

Fl cabbage 0.01 0.01 0.01

ID potato 0.06 0.06 0.06

Airblast Application

NC apple 0.29 0.29 0.28

PA apple 0.29 0.29 0.28

OR apple 0.20 0.20 0.20

CA citrus 0.06 0.06 0.06

FL citrus 0.19 0.19 0.19

GA peach 0.14 0.14 0.14

GA Pecans 0.22 0.22 0.21

CA Grapes 0.07 0.07 0.07

Ground Application Ground Boom, Air Curtain or other method
Page 32 of 125 

Scenario* Peak EEC 21-Day EEC 60-Day EEC

MS Cotton 0.50 0.49 0.48

FL cucumber 0.10 0.10 0.10

CA Tomato 0.02 0.02 0.02

FL Cabbage 0.09 0.09 0.09

CA Lettuce 0.01 0.01 0.01

ID potato 0.06 0.06 0.06

CA Grapes 0.03 0.03 0.02

* See Table 2.2 for application rate information and Table 3.3 for input parameters used to generate the pore water 

EECs. Aquatic EECs for all aerial applications except potato include a 150 ft spray drift buffer per the proposed 

label.

3.3.2 Aquatic Exposure Monitoring and Field Data

No national-scale monitoring data were available for this chemical in the United States. Though 

indoor greenhouse use is approved no outdoor uses have been registered to date.

3.4 Terrestrial Wildlife Exposure Estimates

Terrestrial wildlife exposure estimates are typically calculated for birds and mammals 

emphasizing uptake of pesticide residues on contaminated vegetative matter and insects as 

dietary items. Pesticide residues on food items are estimated based on the assumption that 

organisms are exposed to a single pesticide residue in a given exposure scenario. The residue 

estimates from spray applications are based on extensive crop/residue research and the resulting 

nomogram by Hoerger and Kenaga (1972) as modified by Fletcher et al. (1994). The research 

correlated residue levels on various terrestrial plant and insect surfaces immediately following 

application at various rates in the field. The maximum residue concentration is an upper-bound 

defined by Fletcher et al. (1994) for each food group was derived from literature and tolerance 

data. 

Dissipation of tolfenpyrad residues on food items following single and multiple applications 

were predicted using a first-order residue degradation half-life with the T-REX v1.5.1 model. TREX assumes a default foliar dissipation half-life estimate of 35 days (Willis and McDowell, 

1987). This half-life is used in lieu of foliar dissipation data specific for tolfenpyrad. The 

maximum predicted residues on avian and mammalian food items (dietary EECs) as a result of 

applications to a variety of crop areas are provided in Table 3.6 and 3.7. 

The residues or EECs on food items may be converted to an ingested single acute oral dose or 

compared directly with sub-acute dietary toxicity data. Single oral dose estimates represent an 

exposure scenario where absorption of the pesticide is maximized over a single ingestion event. 

The EEC is converted to an oral dose by multiplying the EEC by the percentage of body weight 

consumed as estimated through allometric relationships. These consumption-weighted EECs are 

determined for each food source and body size for birds (20, 100, and 1000 g) and mammals (15, 

35, and 1000 g). EEC equivalent doses for birds and mammals are given in Tables 3.6 and 3.7, 

respectively. Example output from T-REX for the maximum use scenario is included in 

Appendix C.
Page 33 of 125 

Table 3.6 Predicted avian exposure concentration estimates for Tolfenpyrad

Dietary Category Dietary 

EEC 

(mg a.i./kg 

diet)

Dose Based EEC (mg a.i./kg-bw)

Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, oriental pear, stone fruits and tree 

nuts ( 2 apps at 0.27 lb ai/acre, 14-d interval)

Short grass 114 130 74 33

Tall grass 52 59 34 15

Broadleaf plants 64 73 42 19

Fruits/pods/seeds 7 8 5 2

Arthropods 44 50.8 29 13

Seeds 1.8 1.0 0.46

Cucurbits (4 applications at 0.21 lb a.i./acre, 14-d interval)

Short grass 139 159 91 4

Tall grass 64 73 42 19

Broadleaf plants 78 89 51 23

Fruits/pods/seeds 9 10 6 3

Arthropods 55 62 36 16

Seeds 2.2 1.3 0.6

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton (2 apps at 0.21 lb a.i./acre, 14-d 

interval)

Short grass 89 101 58 26

Tall grass 41 47 26 12

Broadleaf plants 49 57 33 14

Fruits/pods 6 6 4 2

Arthropods 35 39 23 10

Seeds 1.4 0.8 0.36

Table 3.7. Upper-bound mammalian exposure concentration estimates for Tolfenpyrad

Dietary Category Dietary 

EEC

(mg a.i./kg 

diet)

Dose Based EEC (mg a.i./kg-bw)

Small

(15g)

Medium

(35 g)

Large

(1000 g)

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, oriental pear, stone fruits and tree 

nuts ( 2 apps at 0.27 lb ai/acre, 14-d interval)

Short grass 114 109 75 17

Tall grass 52 50 34 8

Broadleaf plants 64 61 42 10

Fruits/pods 7 7 5 1.0

Arthropods 44 43 29 6.8

Seeds 1.8 1.0 0.46

Cucurbits (4 applications at 0.21 lb a.i./acre, 14-d interval)

Short grass 139 133 92 21

Tall grass 64 61 42 10

Broadleaf plants 78 75 52 12
Page 34 of 125 

Dietary Category Dietary 

EEC

(mg a.i./kg 

diet)

Dose Based EEC (mg a.i./kg-bw)

Small

(15g)

Medium

(35 g)

Large

(1000 g)

Fruits/pods 9 8.3 6 1.3

Arthropods 46 52 32 15

Seeds 2.2 1.3 0.6

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton (2 apps at 0.21 lb a.i./acre, 14-d 

interval)

Short grass 89 84 58 14

Tall grass 41 39 27 6.2

Broadleaf plants 49 48 33 7.6

Fruits/pods 6 5 3.6 0.9

Arthropods 35 39 23 10

Seeds 1.4 0.8 0.36

3.4.1 Inhalation Exposure

The screening risk assessment also considered acute inhalation exposure from spray material in 

droplet form at the time of application and vapor phase pesticide volatilizing from treated 

surfaces. Based on STIR tool (version 1.0) results acute inhalation from tolfenpyrad application 

is not considered an appreciable route of exposure for mammals or birds. See Appendix C for 

model output details.

3.4.2 Dermal Exposure

Though dermal exposure via direct application of ground or aerial spray and by incidental 

contact with contaminated vegetation, soil and water is expected from labeled methods of 

application, this screening assessment does not quantify dermal tolfenpyrad exposure to 

terrestrial organisms.

3.4.3 Drinking Water Exposure

Drinking water exposure to a pesticide active ingredient may be the result of consumption of 

surface water or consumption of the pesticide in dew or other water on the surfaces of treated 

vegetation. For pesticide active ingredients with the potential to dissolve in runoff, puddles on 

the treated field may contain the chemical. The SIP tool (version 1.0) estimates the potential for 

exposure concerns to birds and mammals via drinking water alone. Tolfenpyrad’s solubility in 

water (0.087 mg/L) and toxicity to avian and mammalian species are inputs for the potential 

upper-bound drinking water calculations. For the acute oral endpoints, 58 mg a.i./kg bw (ebra 

finch ED50) was selected for birds and 239 mg a.i./kg bw (rat LD50) for mammals. Inputs for 

weight of the test organisms included 0.012 kg for birds (mean body weight of birds at zebra 

finch test initiation) and 0.35 kg for mammals (the default body weight for rats). For birds, a

definitive NOAEC was not established, due to effects at the lowest treatment levels in both 

submitted reproductive studies (9.7 mg a.i./kg diet for mallard duck and 24.3 mg a.i./kg diet for 
Page 35 of 125 

bobwhite quail). Therefore, the potential for chronic effects from drinking water exposure was 

not estimated. The chronic NOAEL value is 0.86 mg a.i./kg bw for mammals. 

Based on the available information, tolfenpyrad exposure through drinking water alone does not 

present an acute concern for mammals or birds or chronic concern for mammals. The potential 

chronic concern from drinking water exposure for birds could not be estimated at this time.

Based on the assumption employed in SIP that the chemical will be present at the level of 

solubility, the estimated upper-bound exposure to birds is 0.0150 mg/kg bw. Therefore, any 

chronic toxicity effects observed at this level would prompt drinking water concerns for 

tolfenpyrad. However, without definitive chronic NOAECs for birds, the potential concern to 

this taxon as a result of chronic drinking water exposure remains an uncertainty.

3.4.4 Exposure of Piscivorous Wildlife

Predicted Residues in Aquatic Prey 

Two approaches were used to predict residues of tolfenpyrad (and degradates) in aquatic 

organisms. The first approach relied on the KABAM model (v. 1.0) which uses a food web 

bioaccumulation model to estimate chemical concentrations in tissues of aquatic organisms. 

The primary chemical-specific inputs to the KABAM model are KOW, KOC, surface water EEC, 

and pore water EEC. For this screening level assessment, the surface water and pore water EEC 

were selected from the exposure scenario yielding the highest EECs (TX Cotton). Other input 

parameters are shown below in Table 3.8 and all input parameters and calculations are shown in 

Appendix E.

Table 3.8. Chemical characteristics of Tolfenpyrad (TX Cotton Scenario).

Characteristic Value Comments/Guidance

Pesticide Name Tolfenpyrad 

(TX Cotton)

Log KOW 5.61 Table 3.1

KOW 407380 .

KOC 

(L/kg OC) 29380 Table 3.1

Time to steady 

state (TS; days) 113 This value is calculated automatically from the Log KOWvalue entered above.

Pore water EEC 

(μg/L) 0.31 From 60-d average EEC for TX Cotton scenario (Table 3.5)

Water Column 

EEC (μg/L) 0.47 From 60-d average EEC for TX Cotton scenario (Table 3.4)

Importantly, available data from the BCF study with tolfenpyrad (MRID 48250424) indicates 

substantially lower bioconcentration than that predicted by the KABAM model using default 

rates of chemical metabolism by biota (Km = 0). Therefore, mean respiratory uptake and 

elimination rate constants determined for whole fish were selected from the BCF study and used 

as input for small, medium and large fish (K1 = 651.5 L/kg-d; K2 – 0.214 d-1). Since the 

elimination rate constant from the BCF study represents total elimination (sum of respiratory 
Page 36 of 125 

elimination, metabolism, dietary elimination), rate constants for all but respiratory elimination 

were set to zero for fish. 

The resulting predicted concentrations of tolfenpyrad in the aquatic food web are shown in Table 

3.9. 

Table 3.9. Estimated concentrations of Tolfenpyrad (TX Cotton) in ecosystem components.

Ecosystem Component

Total 

concentration 

(μg/kg-ww)

Lipid 

normalized 

concentration 

(μg/kg-lipid)

Contribution 

due to diet 

(μg/kg-ww)

Contribution 

due to 

respiration 

(μg/kg-ww)

Water (total)* 0.47 N/A N/A N/A

Water (freely dissolved)* 0.47 N/A N/A N/A

Sediment (pore water)* 0.31 N/A N/A N/A

Sediment (in solid)** 364 N/A N/A N/A

Phytoplankton 8,036 401795 N/A 8,035.90

Zooplankton 7,146 238190 735.24 6,410.46

Benthic Invertebrates 8,559 285299 1,958.67 6,600.29

Filter Feeders 5,610 280498 1,263.39 4,346.58

Small Fish 3,254 81354 1,855.85 1,398.30

Medium Fish 2,392 59793 990.41 1,401.32

Large Fish 1,712 42796 284.30 1,427.53

* Units: μg/L; **Units: μg/kg-dw

The predicted BCF and BAF values for tolfenpyrad are shown in Table 3.10. Notably, BCF 

values for whole fish are similar to those from the submitted BCF study. The predicted BCF and 

BAF values for the lower food web components are greater than those for fish because no 

information was available for estimating metabolism rates for these organisms and no 

adjustments were made to model-calculated rates for uptake, elimination or metabolism. 

Table 3.10. Total BCF and BAF values of Tolfenpyrad (TX Cotton) in aquatic trophic levels.

Trophic Level

Total BCF 

(μg/kg-ww)/(μg/L)

Total BAF 

(μg/kg-ww)/(μg/L)

Phytoplankton 19555 17098

Zooplankton 13933 15204

Benthic Invertebrates 14957 18211

Filter Feeders 9832 11936

Small Fish 2993 6924

Medium Fish 2993 5089

Large Fish 3044 3642

The second approach used to predict tolfenpyrad in aquatic organisms involved the use of the 

measured bioconcentration factor (BCF). Specifically, a steady-state, whole-fish BCF of 3,008 

L/kg wet wt was used in conjunction with the maximum 60-d average EEC in surface water 

(0.47) to estimate tolfenpyrad TROC in fish tissue. This whole body fish BCF represents 

concentrations of parent tolfenpyrad and any degradates that formed during the exposure portion 
Page 37 of 125 

of the BCF study. Because residues of specific degradates were not quantified in this BCF study, 

it is not known what fraction of the residues in water or fish tissue represented parent or 

degradation products.

Using the results of the empirical fish BCF studies, the residue concentrations in fish can be 

predicted using the following equation:

Residue in fish (μg/kg wet wt) = BCF (L/kg whole fish) * 60-d EEC (μg/L) 

For the parent compound: If the BCF is multiplied by the maximum 60-day EEC for 

tolfenpyrad, then the predicted residue concentration in fish is 3008 L/kg wet wt x 0.47 μg/L = 

1,413 μg/kg wet wt or 1.4 mg/kg wet wt. 

These residue values are used for risk estimation in Section 5.1.

3.5 Terrestrial and Semi-Aquatic Plant Exposure Estimates 

Terrestrial and semi-aquatic plants may be exposed to pesticides from runoff, spray drift, or 

volatilization. Semi-aquatic plants are those that inhabit low-lying wet areas that may be dry at 

certain times of the year. The runoff scenario in TerrPlant v1.2.2 is: (1) based on a pesticide's 

water solubility and the amount of pesticide present on the soil surface and its top one 

centimeter, (2) characterized as "sheet runoff" (one treated acre to an adjacent acre) for dry areas, 

(3) characterized as "channel runoff" (10 acres to a distant low-lying acre) for semi-aquatic or 

wetland areas, and (4) based on runoff values of 1, 2, and 5% for water solubility values of <10, 

10-100, and >100 ppm, respectively. Spray drift is assumed as (1) 1% for ground application, (2) 

5% for aerial, airblast, forced air, and spray chemigation applications, and (3) 0% for granular 

applications. Currently, EFED derives plant exposure concentrations from a single maximum 

application rate only. Exposure through volatilization is not accounted for in this baseline 

assessment. However, based on the low vapor pressure of tolfenpyrad, volatilization is not 

expected to be a significant route of exposure. EECs are presented in Table 3.11. The TerrPlant 

model outputs are provided in Appendix D. 

Table 3.11. Tolfenpyrad exposure to terrestrial and semi-aquatic plants based on 

maximum proposed use rate

Description

Ground spray EECs

(lbs a.i./A)

Aerial spray EECs

(lbs a.i./A)

Runoff to dry areas 0.0027 0.0021

Runoff to semi-aquatic areas 0.027 0.021

Spray drift 0.0027 0.0021

Total for dry areas 0.0027 0.0042

Total for semi-aquatic areas 0.0297 0.0231
Page 38 of 125 

4.0 Ecological Effects Analysis

Only studies submitted by the registrant were evaluated to determine the effects of tolfenpyrad

on non-target organisms. A search of the public ECOTOX database (http://cfpub.epa.gov/ecotox) 

on January 12, 2011 did not yield any additional aquatic or terrestrial open literature studies for 

tolfenpyrad. No ecological incidents have been reported to the Agency for tolfenpyrad in the 

United States.

4.1 Aquatic Effects Summary

The acute and chronic toxicity of tolfenpyrad was determined for a variety of fish, invertebrate 

and algal species. Acute toxicity studies were also conducted on selected species with the enduse products, as well as 4 acute freshwater fish studies with the degradates PT(A)-4OH, PCA, 

PAM and PT-CA and the rainbow trout, Oncorhynchus mykiss and 1 acute study with PC-TA 

and a freshwater carp, Cyprinus carpio.

In studies where only nominal concentrations are reported, tolfenpyrad toxicity is may be 

underestimated or overestimated, particularly if tolfenpyrad is unstable in the test conditions and 

degrades to metabolites that differ from those that comprise the modeled exposure 

concentrations. Stability problems were observed in the submitted acute studies with 

Tolfenpyrad 15SC conducted with one fish species. The studies that reported nominal 

concentrations only were not used in risk estimation.

4.1.1 Toxic Effects to Fish

Acute Toxicity 

Freshwater Fish

For freshwater fish species, tolfenpyrad is very highly toxic on an acute basis (Table 4.1). 

Freshwater fish studies are also used as a surrogate for aquatic-phase amphibians. In 96-hour 

studies with bluegill (Lepomis macrochirus), the LC50 is 0.94 μg ai/L for tolfenpyrad technical 

and LC50 is 1.02 μg ai/L for the end-use product Tolfenpyrad 15% SC (MRIDs 47447721 and 

48250415). The bluegill study with the end-use product was classified as supplemental, due to 

poor recovery of the test compound under the static conditions of the test.

Rainbow trout (Oncorhynchus mykiss) appeared to be slightly more sensitive to tolfenpyrad than 

bluegill based on the available acute studies. For the technical product, the LC50 for rainbow 

trout is 0.163 μg ai/L, and in the submitted study conducted with Tolfenpyrad 15% SC, the LC50

for this species is 0.114 μg ai/L (MRIDs 48250413 and 48250416). The rainbow trout study with 

the end-use product was classified as supplemental, due to poor recovery of the test compound 

under the static conditions of the test.
Page 39 of 125 

Three acute studies with tolfenpyrad technical and carp (Cyprinus carpio) were also submitted. 

All three studies were classified as supplemental. For the carp study using tolfenpyrad technical, 

the LC50 is 3.2 μg a.i./L (MRID 47447719). This study was determined to be supplemental due 

to instability of the test material under the test conditions. For the carp study using tolfenpyrad 

EC, the LC50 is 45 μg a.i./L (MRID 47447720). This study was also classified as supplemental 

because only nominal test concentrations were reported. An additional study was submitted with 

carp exposed tolfenpyrad SC. In this test, the LC50 is 20 μg a.i./L, but the study is classified as 

supplemental because the chemical concentrations were not analytically verified and the results 

are based on nominal concentrations (MRID 48250417).

Estuarine/Marine Fish

The single acute study was submitted for estuarine/marine fish indicates that tolfenpyrad is very 

highly toxic to this taxon on an acute basis. This study was conducted with tolfenpyrad technical 

and the test species sheepshead minnow (Cyprinodon variegatus) and the 96-hour LC50 is 3.38 

μg ai/L (MRID 48250414).

Chronic Toxicity

Freshwater Fish

Both a 33-day early life stage study and a 30-week full life cycle study were submitted for the 

freshwater fish species fathead minnow (Pimephales promelas). In the early life stage study, 

effects on growth were observed at the all treatment levels, 0.014 μg TRR/L to 484 μg TRR/L, 

compared to the negative control. However, the negative control results were confounded by the 

fact that one exceptionally large fish was present in this group, and skewed the variance for 

weight measurements. In addition, seven fish were lost in transfer during the test, and this could 

result in more food for the remaining test organisms in the negative control. Therefore, the 

growth results for this test are not reliable, and the NOAEC is for survival only. This may 

potentially underestimate toxicity, due to the lack of a reliable growth endpoint for this study. 

(MRID 48250422). This study is classified as supplemental, because the chemical concentrations 

were only reported in terms of total radioactive residues, and the observed radioactivity was not 

characterized as parent or degradates. In addition, substantial variability in the measured 

chemical concentrations occurred among samples within a given treatment level. In the full life 

cycle study, the NOAEC is 0.189 μg ai/L, based on reductions in juvenile survival and clinical 

signs of toxicity at the 0.395 μg ai/L treatment level and higher (MRID 48250423). The study 

was also classified as supplemental, because the treatment concentrations were only reported in 

terms of total radioactive residues and the observed radioactivity was not characterized as parent 

or degradates. 

Estuarine/Marine Fish

An early life stage study with the estuarine/marine fish species sheepshead minnow (Cyprinodon 

variegatus) was also submitted for tolfenpyrad technical. In this study, the NOAEC is 0.186 μg 

ai/L, based on reductions in growth and clinical signs of toxicity at the 0.573 μg ai/L treatment 

level and higher (MRID 48250421). This study is classified as supplemental, due to analytical 

variability in test concentration measurements and because the treatment concentrations were 

only reported in terms of total radioactive residues. The observed radioactivity was not 

characterized as parent or degradates.
Page 40 of 125 

Degradation Products 

Tofenpyrad PCA, PC-TA, PT(A)-4OH and PAM metabolites were of less concern with fish with 

observed acute LC50 values ranging from 640 ppb to over 10,000 ppb, which are over 4000 times 

less toxic than the parent for Rainbow trout (LC50 0.163 ppb). 

Table 4.1 summarizes the available tolfenpyrad toxicity studies submitted to the Agency for fish 

species.

Table 4.1 Acute and chronic toxicity of tolfenpyrad and its major degradation products to 

fish.

Percent 

Active 

Ingredient

Species Toxicity Value

(Endpoints)

Acute 

Toxicity 

Classification

Study 

Classification

MRID

citation

99.5 Bluegill sunfish,

Lepomis macrochirus

96 hr LC50 = 0.94 μg a.i./L

NOAEC = 0.24 μg a.i./L

Very highly 

toxic Acceptable 47447721

15.4 SC Bluegill sunfish 96 hr LC50 = 1.02 μg a.i./L

NOAEC = 0.37 μg a.i./L

Very highly 

toxic Supplemental 48250415

99.5 Rainbow trout,

Oncorhynchus mykiss

96 hr LC50 = 0.163 μg a.i./L*

NOAEC = 0.059 μg a.i./L

Very highly 

toxic Acceptable 48250413

15.4 Rainbow trout

96 hr LC50 = 0.740 μg form 

/L ( = 0.114 ppb of active/L)

NOAEC = 0.387 μg form./L

Very highly 

toxic Supplemental 48250416

99.3 Common carp,

Cyprinus carpio

96 hr LC50 = 3.2 ug a.i./L

NOAEC < 2.4 ug a.i./L

Very highly 

toxic Supplemental 47447719

15.5 EC Common carp

96 hr LC50 = 45 ug form/L

NOAEC = 18 ug form/L Highly toxic Supplemental 47447720

15.9 SC Common carp96 hr LC50 = 20 ug form/L

NOAEC = 10 ug form /L Highly toxic Supplemental 48250417

99.4

Fathead minnow,

Pimephales promelas

33 Day Early Life NOAEC = 

0.188* μg TRR/L

LOAEC = 0.484 μg TRR/L

Not applicable Supplemental 48250422

99.4 Fathead minnow 210 Day Lifecycle NOAEC = 0.189 μg TRR/L

LOAEC = 0.395 μg TRR/L

Not applicable Supplemental 48250423

99.5

Sheepshead minnow,

Cyprinodon 

variegatus 

96 hr LC50 = 3.38 μg a.i./L*

NOAEC = 1.22 μg a.i./L

Very highly 

toxic Acceptable 48250414

99.4 Sheepshead minnow

34 day Early Life NOAEC = 

0.186 μg TRR/L*

LOAEC = 0.573 μg TRR/L

Not applicable Supplemental 48250421

Metabolite Acute Toxicity Test Results

99.6 PT(A)-

4OH Rainbow trout 3100 ug ai/L Moderately 

toxic Acceptable 48953801

99.7 PCA Rainbow trout > 9700 ug ai/L > Moderately 

toxic Acceptable 48953802

99.7 PAM Rainbow trout >10,000 ug ai/L > Slightly 

toxic Acceptable 48953803

100 PT-CA Rainbow trout 640 ug ai/L Moderately Acceptable 48953804
Page 41 of 125 

4.1.2 Toxic Effects to Aquatic Invertebrates

Acute Toxicity

Freshwater Invertebrates

Tolfenpyrad technical is very highly toxic to aquatic invertebrates on an acute basis (Table 4.2). 

Based on observations of daphnid immobilization at measured concentrations, the 48-hour EC50

was 1 μg a.i./L (MRID 47490701). An acute aquatic invertebrate toxicity test for the end-use 

product Tolfenpyrad 15EC was also submitted. This study also indicated very high toxicity to 

daphnids, with a 48-hour EC50 of 1.2 μg a.i./L (MRID 47447718). However, this study reported 

only nominal concentrations and is classified as supplemental.

Estuarine/marine Invertebrates

Two studies were submitted that examined the acute toxicity of tolfenpyrad to estuarine/marine 

invertebrate species. In a test conducted on the saltwater mysid (Americamysis bahia), the 96-

hour LC50 was determined to be greater than 12 μg ai/L (MRID 48250412). This study was 

classified as supplemental, because the test material was not tested at high enough concentrations 

to determine a definitive LC50. An acute 96-hour study was also conducted with the eastern 

oyster (Crassostrea virginica), which resulted in an EC50 greater than 7.8 μg a.i./L (MRID 

48250411). This study is classified as supplemental because the test concentrations did not 

bracket the EC50. 

Chronic Toxicity 

Freshwater Invertebrates

A full-life cycle study with tolfenpyrad technical was submitted for the freshwater invertebrate 

Daphnia magna (MRID 48250418). Based on the results of this study, chronic effects such as 

delayed offspring production and reduction in the number of offspring were observed at 

concentrations of 0.482 μg a.i./L or greater. The NOAEC for this study was defined as 0.244 μg 

a.i./L. 

Estuarine/marine Invertebrates

A full-life cycle study with tolfenpyrad technical was submitted for the saltwater mysid 

Americamysis bahia (MRID 48250420). Based on the results of this study, chronic effects such 

as reductions in offspring production and juvenile survival were observed at concentrations of 

5.4 μg a.i./L or greater. The NOAEC for this study was defined as 2.3 μg a.i./L. This study was 

classified as supplemental due to analytical variation and because the treatment concentrations 

were only reported in terms of total radioactive residues (the observed radioactivity was not 

characterized as parent or degradates).

Benthic Invertebrates

A 28-day spiked sediment study with the freshwater benthic midge Chironomus riparius was 

submitted that examined the effects of tolfenpyrad technical on emergence and development rate. 

toxic

PC-TA Common carp 940 ug ai/L Moderately 

toxic 48660302
Page 42 of 125 

In this study, no adverse effects were observed on midge emergence or development rate at the 

highest treatment level, >0.391 μg TRR/kg sediment or >0.029 μg TRR/L pore water. This study 

is considered supplemental information, as the treatment concentrations were reported in terms 

of total radioactive residues (the observed radioactivity was not characterized as parent or 

degradate), the test was not conducted with an OCSPP guidelines species (MRID 48250425) and 

no reproductive endpoints were evaluated.

Transformation Products

No acute or chronic aquatic toxicity information was submitted for any degradate of tolfenpyrad

with aquatic invertebrates.

Table 4.2 summarizes the available tolfenpyrad toxicity studies submitted to the Agency for 

aquatic invertebrates.

Table 4.2. Tolfenpyrad Toxicity to Aquatic Invertebrates

Study 

Type

Percent 

Active 

Ingredient

Species Toxicity Value

(Endpoints)

Acute 

Toxicity 

Classification

Study 

Classification

MRID

citation

48-hour 

acute 99.3

Daphnia 

magna

(daphnid)

EC50 = 1.00 μg 

a.i./L*

NOAEC = 0.500 

μg a.i./L

Very highly 

toxic Acceptable 47490701

48-hour 

acute

15.5

Tolfenpyrad 

15 EC

Daphnia 

magna

(daphnid)

EC50 = 1.2 μg 

a.i./L

NOAEC = 0.30 

μg a.i./L

Very highly 

toxic Supplemental 47447718

21-day 

chronic 

life-cycle

99.5

Daphnia 

magna

(daphnid)

NOAEC = 0.244 

μg a.i./L*

LOAEC = 0.482 

μg a.i./L

Not applicable Acceptable 48250418

28-day 

chronic 99.4

Chironomus 

riparius 

(midge)

Time-Weighted 

Average 

Sediment 

Concentrations

NOAEC: 0.391 

μg TRR/kg

LOAEC: >0.391 

μg TRR/kg

Time-Weighted 

Average Pore 

Water 

Concentrations

NOAEC: 0.029

μg TRR/L

LOAEC: >0.029

μg TRR/L

Not applicable Supplemental 48250425

96-hour 

acute 99.5

Crassostrea 

virginica

(Eastern 

EC50 > 7.80 μg 

a.i./L

NOAEC = 1.82 

Could not be 

determined Supplemental 48250411
Page 43 of 125 

4.1.3 Toxic Effects to Aquatic Vascular Plants and Algae

The submitted tolfenpyrad technical study for Lemna gibba indicates that tolfenpyrad is not toxic 

aquatic vascular plants up to the highest concentration tested, 30 μg a.i./L (MRID 48250436).

This study was classified as supplemental because the EC50 value could not be defined.

Tolfenpyrad technical showed a range of phytotoxic effects to algae. The EC50 values in the 

submitted studies ranged from 1.00 μg a.i./L for Pseudokirchnierella subcapitata (freshwater 

algae) to greater than 87 μg a.i./L for another freshwater algal species, Anabaena flos-aquae. 

Many of the submitted studies with tolfenpyrad technical were considered supplemental because 

the treatment concentrations did not allow calculation of a definitive EC50. The study conducted 

with tolfenpyrad technical and Skeletonema costatum is considered supplemental because the 

initial cell density in this study is approximately 1/8 the recommended density in OCSPP 850. 

5400 (MRID 48250440).

Two acute algal studies were also submitted for the tolfenpyrad end-use products. For 

tolfenpyrad 15% EC, the EC50 is 180 μg ai/L (MRID 47447726). However, this study reported 

only nominal concentrations and is classified as supplemental. Another submitted study with 

tolfenpyrad 15% SC resulted in an EC50 of 320 μg ai/L (MRID 48250441). This study was also 

classified as supplemental because no measured concentrations were reported. 

Table 4.3 summarizes the available tolfenpyrad toxicity studies for aquatic vascular plants and 

algae. The Office of Pesticide Programs has not established toxicity classifications for aquatic 

plants.

Table 4.3. Tolfenpyrad Toxicity to Aquatic Vascular Plants and Algae

oyster) μg a.i./L

96-hour 

acute 99.5

Americamysis 

bahia

(saltwater 

mysid)

LC50 > 12 μg 

a.i./L

NOAEC = 12 μg 

a.i./L

Could not be 

determined Supplemental 48250412

35-day 

chronic 

life cycle

99.5

Americamysis 

bahia

(saltwater 

mysid)

NOAEC = 2.3 μg 

TRR/L*

LOAEC = 5.4 μg 

TRR/L

Not applicable Supplemental 48250420

*Toxicity value used in risk estimation.

Study 

Type

Percent 

Active 

Ingredient

Species Toxicity Value

(Endpoints)

Study 

Classification

MRID

citation

7-day 99.5 Lemna gibba 

(duckweed)

EC50 >30 μg a.i./L

NOAEC = 30 μg a.i./L* Supplemental 48250436

72-hour 

acute 99.3

Pseudokirchnierella 

subcapitata 

(freshwater algae)

EC50 = 1.00 μg a.i./L*

NOAEC = 0.500 μg a.i./L* Acceptable 47447725
Page 44 of 125 

4.2 Terrestrial Effects Summary

Fourteen studies were submitted that evaluated the effects of tolfenpyrad to terrestrial non-target 

organisms. The plant studies were conducted using a technical end-use product (TEP), 

Tolfenpyrad 15% SC. Tolfenpyrad acute toxicity to birds and mammals ranges from practically 

non-toxic to moderately toxic. Chronic effects were also observed at environmentally-relevant 

concentrations for birds and mammals.

4.2.1 Toxic Effects on Birds

Toxicity studies with tolfenpyrad were performed with bobwhite quail (Colinus virginianus), 

mallard duck (Anas platyrhynchos), and zebra finch (Poephila guttata). An overview of avian 

toxicity data is given in Table 4.4.

Acute and short-term dietary toxicity 

For avian species, tolfenpyrad is moderately toxic on an acute oral basis, and slightly toxic based 

on a 5-day dietary study. Bird studies are also used as a surrogate for terrestrial-phase 

amphibians and reptiles. The LD50 for bobwhite quail (Colinus virginianus) was 87 mg ai/kg bw, 

based on an acute oral dosing followed by a 14-day observational period (MRID 47447722). In 

the acute oral study with the zebra finch (Poephila guttata), an LD50 could not be calculated due 

to substantial levels of regurgitation at all treatment levels in the study. The calculated ED50 for 

this study was 58.0 mg a.i./kg bw, based on treatment-related regurgitation effects (MRID 

48250426).

For the 5-day dietary studies conducted with avian species, the LC50 was 1348 mg ai/kg diet for 

bobwhite quail and the LC50 was 3543 mg ai/kg diet for mallard duck (MRIDs 47447723 and 

48250427).

96-hour 

acute 99.5

Pseudokirchnierella 

subcapitata 

(freshwater algae)

EC50 > 10 μg a.i./L

NOAEC = 2.7 μg a.i./L Supplemental 48250437

72-hour 

acute

15.5

Tolfenpyrad 

15SC

Pseudokirchnierella 

subcapitata 

(freshwater algae)

EC50 = 180 μg ai/L

NOAEC = 102 μg a.i./L Supplemental 47447726

72-hour 

acute

15.9

Tolfenpyrad 

15EC

Pseudokirchnierella 

subcapitata 

(freshwater algae)

EC50 = 320 μg a.i./L

NOAEC = 5 μg a.i./L Supplemental 48250441

96-hour 

acute 99.5 Anabaena flos-aquae(freshwater algae)

EC50 >87 μg a.i./L

NOAEC = 87 μg a.i./L Supplemental 48250438

96-hour 

acute 99.5 Navicula pelliculosa (freshwater diatom)

EC50 >24 μg a.i./L

NOAEC = 24 μg a.i./L Supplemental 48250439

96-hour 

acute 99.5 Skeletonema costatum (marine diatom)

EC50 = 5.2 μg a.i./L

NOAEC = 1.2 μg a.i./L Supplemental 48250440

*Toxicity value used in risk estimation.
Page 45 of 125 

Chronic toxicity

Two studies were submitted that examined the chronic toxicity of tolfenpyrad dietary exposure 

to avian species. Tolfenpyrad showed chronic toxic effects to birds at levels as low 9.7 mg a.i./kg 

diet. Both the study submitted for bobwhite quail (Colinus virginianus) or mallard duck (Anas 

platyrhynchos) were classified as supplemental, as effects were observed at the lowest treatment 

level and a NOAEC could not be defined. 

In the submitted chronic study with bobwhite quail, eggs set/eggs laid was reduced by 4 percent 

(statistically significant) at the lowest treatment level, 24.3 mg a.i./kg diet. The biological 

significance of this reduction is not clear however, as the number of eggs set/eggs laid was not 

observed at the other two higher treatment levels. The number of hatchlings/eggs laid was 

reduced by 9-15% at the two lowest treatment levels and not the highest treatment level. In this 

study, hatchling survival per pen is also reduced at the second highest treatment level only, 51.1 

mg a.i./kg diet. No other parameters showed statistical difference from the controls (MRIDs 

48250430 and 48250431).

In the study with mallard ducks, a statistically-significant reduction in the number of eggs set to 

eggs laid was observed at all treatment levels, 9.7 mg a.i./kg diet and greater. The reduction did 

not increase with dose and remained fairly constant, between a 10 to 11 percent reduction 

compared to the controls (MRIDs 48250428 and 48250429). 

Table 4.4 summarizes the available tolfenpyrad toxicity studies conducted with avian species.

Table 4.4. Tolfenpyrad Toxicity to Birds

Study 

Type

Percent 

Active 

Ingredient

Species Toxicity Value

(Endpoints)

Acute 

Toxicity 

Classification

Study 

Classification

MRID

citation

Acute 

single oral 

dose, 14-

day 

observation 

period

99.5

Zebra finch 

(Poephila 

guttata)

ED50 = 58.0 mg 

a.i./kg bw* 

NOAEL < 13.0 

mg a.i./kg bw

Could not be 

determined Supplemental 48250426

Acute 

single oral 

dose, 14-

day 

observation 

period

99.3

Northern 

bobwhite quail 

(Colinus 

virginianus)

LD50 = 87 mg 

a.i./kg bw

NOAEL <25 mg 

a.i./kg bw

Moderately 

toxic Acceptable 47447722

Subacute 5-

day dietary 

exposure, 

4-day 

observation 

period

99.3

Northern 

bobwhite quail 

(Colinus 

virginianus)

LC50 = 1348 mg 

a.i./kg diet*

NOAEC <156 

mg a.i./kg diet

Slightly toxic Acceptable 47447723

Subacute 5-

day dietary 

exposure, 

4-day 

observation 

period

99.5

Mallard duck 

(Anas 

platyrhynchos)

LC50 = 3543 mg 

a.i./kg diet

NOAEC <98 mg 

a.i./kg diet

Slightly toxic Acceptable 48250427
Page 46 of 125 

4.2.2 Toxic Effects on Mammals

Acute oral, dermal and inhalation studies with tolfenpyrad were conducted on rats. A onegeneration reproduction study with tolfenpyrad was also submitted. Results of the mammalian 

toxicity studies are summarized in Table 4.5. Formal reviews of the acute mammalian data were 

conducted by the Registration Division (DP 354428). The Health Effects Division reviewed the 

chronic mammalian dietary study described below (D383820). All studies were classified as 

acceptable.

Acute toxicity

Tolfenpyrad is practically nontoxic to moderately toxic to mammals on an acute oral basis (male 

LD50 ≥ 386 mg a.i./kg bw; female LD50 ≥ 150 mg a.i./kg bw; combined LD50 ≥ 239 mg a.i./kg 

bw). Mortality was observed at all treatment levels, excluding the lowest treatment (50 mg a.i./kg 

bw). Of the treated animals, 1 of 5 rats died at 75 mg a.i./kg bw, 1 of 10 rats died at 100 mg 

a.i./kg bw, 2 of 10 rats died at 150 mg a.i./kg bw, 6 of 10 rats died at 250 mg a.i./kg bw, 4 of 5 

rats died at 500 mg a.i./kg bw and 4 of 5 rats died at 750 mg a.i./kg bw. Clinical signs of toxicity 

were observed at treatment levels as low as 50 mg a.i./kg bw, and included thin appearance, redstained face, alopecia on the nape of neck, soft stool, and yellow stained urogenital area (MRID 

47457501). 

On an inhalation basis, the tolfenpyrad mammalian LC50 males > 2.21 mg a.i./L, LC50 females > 

1.50 mg a.i./L and LC50 combined > 1.82 mg a.i./L. One of 10 test animals died at this treatment 

level. At the two highest treatment levels (3.99 mg a.i./L and 5.32 mg a.i./L), 2 out of 10 and 7 

out 10 test animals died, respectively. Lungs were abnormally red, had dark patches, 

hemorrhagic, and dark foci in animals that died or were sacrificed (MRID 47447734).

Chronic toxicity

Chronic reproductive effects were observed at low levels of tolfenpyrad exposure. In the 

submitted one-generation reproduction conducted on rats, the parental NOAEL was 15 ppm or 

0.86/0.92 mg a.i./kg/day for males and females, respectively. Decreased body weight gain and 

20-week 

chronic 

dietary 

exposure

99.5

Mallard duck 

(Anas 

platyrhynchos)

NOAEC <9.7 

mg ai/kg diet

LOAEC = 9.7 

mg ai/kg diet

Not applicable Supplemental

48250428 

and 

48250429

22-week 

chronic 

dietary 

exposure

99.5

Northern 

bobwhite quail 

(Colinus 

virginianus)

NOAEC <24.3 

mg ai/kg diet

LOAEC = 24.3 

mg ai/kg diet

Not applicable Supplemental

48250430 

and 

48250431 

*Toxicity value used in risk estimation.
Page 47 of 125 

food consumption were observed at tolfenpyrad concentrations of 50 ppm (2.7/2.9 mg/kg/day) 

and greater. Adverse effects on body weight of offspring were observed at the same levels, 

resulting in an offspring NOAEL of 50 ppm. The gestation duration for female rats was 

increased at treatment levels of 100 ppm (4.8/4.4 mg a.i./kg/day) and greater. Therefore, the 

NOAEL in this study for reproductive endpoints was 50 ppm (2.7/2.9 mg/kg/day) (MRID 

47447816). Table 4.5 summarizes the available tolfenpyrad toxicity studies conducted with 

mammalian species.

Table 4.5. Tolfenpyrad Toxicity to Mammals

Study Type

Percent 

Active 

Ingredient Species Toxicity Value(Endpoints)

Acute 

Toxicity 

Classification

Study 

Classification

MRID

Citation

Single oral 

dose, 14-day 

observation 

period

99.3

Laboratory 

Rat

(Rattus 

norvegicus)

Male LD50 ≥ 386 mg 

a.i./kg bw

Female LD50 ≥ 150 mg 

a.i./kg bw

Combined LD50 ≥ 239 

mg a.i./kg bw*

Moderately 

nontoxic to 

practically 

nontoxic

Acceptable 47457501

4-hour 

inhalation 

dose (nose 

only)

Purity not 

reported, 

technical 

grade 

active 

ingredient

Laboratory 

Rat

(Rattus 

norvegicus)

Male LC50 ≥ 2.21 mg 

a.i./L

Female LC50 ≥ 1.50 mg 

a.i./L

Combined LC50 ≥ 1.82 

mg a.i./L

Not applicable Acceptable 47457734

Onegeneration rat 

reproduction 

study, dietary 

exposure 

began 4 

weeks prior to 

mating and 

lasted 

throughout 

mating, 

gestation and 

lactation 

periods

99.8

Laboratory 

Rat

(Rattus 

norvegicus)

Parental NOAEL = 15 

ppm or 0.86/0.92 mg 

a.i./kg bw/day*

Parental LOAEL = 50 

ppm or 2.7/2.9 mg 

a.i./kg bw/day

Reproductive NOAEL 

= 50 ppm or 2.7/2.9 mg 

a.i./kg bw/day 

Reproductive LOAEL 

= 100 ppm or 4.8/4.4 

mg a.i./kg bw/day

Offspring NOAEL = 15 

ppm or 0.86/0.92 mg 

a.i./kg bw/day*

Offspring LOAEL = 

2.7/2.9 mg a.i./kg 

bw/day

Not applicable Acceptable 47447816

*Toxicity value used in risk estimation.
Page 48 of 125 

4.2.3 Toxic Effects on Terrestrial Invertebrates

The honey bee is used as a surrogate for all terrestrial non-target invertebrates. For the technical 

grade active ingredient, tolfenpyrad is classified as highly toxic based on the acute contact honey 

bee study (LD50 = 0.47 μg a.i./bee). Similarly, the acute oral study with honey bees resulted in an 

LD50 of 0.63 μg a.i./bee. Behavioral abnormalities included uncoordinated movements and 

apathy in both the acute contact and oral study.

In the acute contact study at 24 hours, 3, 13, 40, 30, and 7% of bees in the 0.16, 0.3, 0.6, 1.3, and 

2.5 μg ai/bee test levels (all test concentrations), respectively, displayed uncoordinated 

movements and apathy. Most of the bees were dead at the 0.6 μg ai/bee treatment level and 

above. After 96 hours, 10 and 3% of the remaining bees in the 0.6 and 1.3 μg ai/bee test levels, 

respectively, displayed abnormalities.

In the acute oral study at 4 hours, 3, 13, and 77% of bees in the 0.39, 0.69, and 1.16 μg ai/bee 

test levels (three highest test concentrations), respectively, displayed uncoordinated movements 

and apathy. By 48 hours there were no abnormalities present, but there was almost complete 

mortality in the 1.16 μg ai/bee test level.

In this study, 40 percent of the bees died following exposure to tolfenpyrad residues aged 8 hours 

after application at 0.266 lbs ai/A (approximately twice the maximum application rate in 

currently proposed labels). After 24 hours, 13 percent of exposed bees died. Twenty percent of 

bees died when exposed to tolfenpyrad residues 48 hours post-application. Although the 

treatment bee response to residues aged 24-hours or greater was not statistically significant from 

the control (5% mortality), the mortality at these treatment levels was substantial and did not 

follow a dose-response pattern. The RT25 is likely between 8 hours and 48 hours, and NOAEL 

could not be determined in this study.

The results from both the acute and contact toxicity tests conducted with terrestrial invertebrates 

are summarized in Table 4.6.

Table 4.6. Tolfenpyrad Toxicity to Nontarget Terrestrial Invertebrates

Study 

Type

Percent 

Active 

Ingredient

Species Toxicity Value

(Endpoints)

Acute 

Toxicity 

Classification

Study 

Classification

MRID

Citation

96-hour 

acute 

contact and 

oral toxicity 

test

99.3

Honey bee

(Apis 

mellifera)

Contact toxicity

LD50 = 0.47 μg 

a.i./bee; NOAEL = 

0.3 μg a.i./bee

Oral toxicity

LC50 = 0.63 μg 

a.i./bee; NOAEL = 

0.27 μg a.i./bee

Highly toxic

Contact 

toxicity test:

Acceptable

Oral toxicity 

test:

Supplemental

48250432

24-hour 

exposure to 

foliar 

residues 

16.5% a.i.

(Tolfenpyrad 

15% SC)

Honey bee

(Apis 

mellifera)

8 hours< RT25 <48 

hours

NOAEL = could 

not be determined

Not applicable Supplemental 48250433
Page 49 of 125 

4.2.4 Toxic Effects on Terrestrial Plants

There were no effects in the submitted studies that resulted in an inhibition of 25% or greater for 

any parameter measured. The seedling emergence and vegetative vigor studies were conducted 

with a single treatment level of 0.265 lbs a.i./A, which approximates the current maximum single 

application rate of 0.27 lb a.i./A. Some uncertainty exists regarding the effects of tolfenpyrad on 

seedling emergence, as a NOAEC could not be established for one dicot species, Lactuca sativa

(lettuce). For lettuce, tolfenpyrad exposure at 0.265 lbs a.i./A caused up to 14 percent inhibition 

of seedling emergence and survival (MRID 48250434).

Both studies were conducted with Tolfenpyrad 15SC. No studies have been submitted that 

examine the toxicity of Tolfenpyrad 15EC to terrestrial plants.

The results of the two available tolfenpyrad studies with terrestrial plants are summarized in 

Table 4.7. The Office of Pesticide Programs has not established toxicity classifications for 

terrestrial plants.

Table 4.7. Tolfenpyrad Toxicity to Terrestrial Plants

Study Type

Percent 

Active 

Ingredient Species Toxicity Value

(Endpoints)

Study 

Classification

MRID

Citation

Seedling 

emergence

16.3 

(Tolfenpyrad 

15% SC)

Monocot species: 

(corn, Zea mays; 

onion, Allium cepa; 

ryegrass, Lolium 

perenne; and wheat, 

Triticum aestivum)

Dicot species: (radish, 

Raphanus sativus; 

sugarbeet, Beta 

vulgaris; lettuce, 

Lactuca sativa; flax, 

Linum usitatissimum; 

soybean, Glycine max; 

and tomato, 

Lycopersicon 

esculentum)

Monocot species*

EC25/IC25:

>0.265/0.270 lbs ai/A

EC05/IC05:

>0.265/0.270 lbs ai/A

NOAEC: 0.265/0.270 

lbs ai/A

Dicot species

EC25/IC25: >0.265 lbs 

ai/A

EC05/IC05: <0.265 lbs 

ai/A

NOAEC: <0.265 lbs 

ai/A (based on 14% 

reduction in lettuce 

seedling emergence 

and survival)

Supplemental 48250434

Vegetative 

vigor

16.3 

(Tolfenpyrad 

15% SC)

Monocot species: 

(corn, Zea mays; 

onion, Allium cepa; 

ryegrass, Lolium 

perenne; and wheat, 

Triticum aestivum)

Dicot species: (radish, 

Raphanus sativus; 

Monocot species

EC25/IC25: >0.265 lbs 

ai/A

EC05/IC05: >0.265 lbs 

ai/A

NOAEC: 0.265 lbs 

ai/A

Acceptable 48250435
Page 50 of 125 

4.5 Review of ECOTOX Data

A search of the public ECOTOX database (http://cfpub.epa.gov/ecotox) was conducted on 

January 12, 2011. No studies were found that evaluated the effects of tolfenpyrad on non-target 

organisms. 

4.6 Review of Incident Data

There are no ecological incidents reported for tolfenpyrad, as expected for a chemical with no 

previously registered outdoor uses. 

A review of the Ecological Incident Information System (EIIS, v. 2.1) and Aggregate Incident 

databases for ecological incidents involving tolfenpyrad was completed on December 27, 2011. 

A search for tolfenpyrad was also conducted in the American Bird Conservancy’s Avian Incident 

Monitoring System (AIMS), which contains publicly available data on reported avian incidents 

involving pesticides (http://www.abcbirds.org/abcprograms/policy/toxins/aims/aims/index.cfm). 

sugarbeet, Beta 

vulgaris; lettuce, 

Lactuca sativa; flax, 

Linum usitatissimum; 

soybean, Glycine max; 

and tomato, 

Lycopersicon 

esculentum)

Dicot species

EC25/IC25: >0.265 lbs 

ai/A

EC05/IC05: >0.265 lbs 

ai/A

NOAEC: 0.265 lbs 

ai/A

*Measured concentrations for all species except onion, sugarbeet, and tomato were <LOQ (<0.0352 lbs ai/A, 

control), and 0.265 lbs ai/A, and were <LOQ (<0.0362 lbs ai/A, control), and 0.270 lbs ai/A for onion, 

sugarbeet, and tomato. 
Page 51 of 125 

5.0 Risk Characterization

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

potential for ecological risks to non-target organisms including aquatic life, wildlife, and plants 

from the use of tolfenpyrad according to the proposed labels. The risk characterization provides 

an estimation and description of the risk; articulates risk assessment assumptions, limitations, 

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

information to make regulatory decisions.

5.1 Risk Estimation Process: Integration of Exposure and Effects Data

Results of the exposure and toxicity effects data are used to evaluate the potential for adverse 

ecological effects on non-target species. For the assessment of potential risks of tolfenpyrad 

(technical grade active ingredient), the risk quotient (RQ) method is used to compare exposure 

and measured acute or chronic toxicity reference values:

RQ = EEC / Toxicity Reference Value

where: EEC is the estimated environmental concentration generated by the exposure scenarios. 

The RQs are compared to the Agency’s levels of concern (LOCs). These LOCs are the Agency’s 

interpretive policy and are used to analyze potential risk to non-target organisms and the need to 

consider regulatory action (see Appendix H). These criteria are used to indicate when a 

pesticide’s use as directed on the label has the potential to cause adverse effects on non-target 

organisms. 

5.1.1 Non-target Aquatic Fish, Invertebrates, and Plants

Peak EECs were compared to definitive acute toxicity endpoints to derive acute risk quotients. 

The 21-day EECs were compared to chronic toxicity endpoints (NOAEC values) to derive 

chronic risk quotients for invertebrates. The 60-day EECs were compared to chronic toxicity 

endpoints (NOAEC values) to derive chronic risk quotients for fish. Peak EECs were compared 

to EC50 values for aquatic plants to calculate risk quotients for non-listed species and NOEC 

values to calculate risk quotients for listed plant species. The following risk estimations apply to 

TGAI toxicity endpoints. 

A summary of the risk quotients for freshwater fish and aquatic invertebrates is presented in 

Table 5.1. For freshwater fish, acute RQ values range from 0.7 to 17 and exceed the acute risk 

to listed species LOC of 0.05 (and the non-listed species LOC of 0.5) for all 22 exposure 

scenarios assessed. Chronic RQ values for freshwater fish range from 0.05 to 3.6 and exceed the 

chronic risk to listed and non-listed species LOC of 1.0 for 9 of the 22 exposure scenarios 

assessed. For freshwater aquatic invertebrates, acute RQ values range from 0.1 to 2.8 and 

exceed the acute risk to listed species LOC (0.05) and non-listed species LOC (0.5) in 22 and 11

exposure scenarios, respectively. Chronic risks to freshwater invertebrates are evident in 10 of 

the 22 exposure scenarios where RQ values meet or exceed the LOC of 1.0 and range from 0.04 

to 3.6.
Page 52 of 125 

Table 5.1 Risk quotients freshwater fish and invertebrates.

Scenario/

Peak EEC 

FW Fish Acute

RQ

FW 

Invertebrate 

Acute RQ

FW 

Invertebrate 

Chronic RQ

FW Fish Chronic

RQ

Aerial Application

CA citrus-150 ft buffer 

(0.21 ppb) 1.3 0.2 2.9 0.26

FL citrus- 150 ft buffer 

(0.78 ppb) 4.8 0.8 1.0 1.2

TX cotton (2.68 ppb) 17 2.7 2.7 2.5

CA cotton (0.20 ppb) 1.2 0.2 0.3 0.1

CA tomatoes (0.17 ppb) 1.0 0.17 0.25 0.2

CA lettuce (0.11 ppb) 0.7 0.1 0.45 0.4

FL cabbage (0.8 ppb) 4.8 0.8 0.16 0.1

ID potato (0.31 ppb) 1.9 0.3 0.45 0.5

Airblast Application

NC apple (1.62 ppb) 10 1.6 2.3 2.2

PA apple (1.24 ppb) 7.6 1.2 1.9 2.2

OR apple (0.85 ppb) 5.2 0.8 1.5 1.5

CA citrus (0.48 ppb) 2.9 0.5 0.6 0.05

FL citrus (0.19 ppb) 1.2 0.2 1.3 1.5

GA peach (0.14 ppb) 0.9 0.1 1.3 1.2

GA pecan (1.44 ppb) 8.8 1.4 1.6 1.7

Ground Application: Ground Boom, Air Curtain Sprayers, or other method

MS Cotton (2.8 ppb) 17 2.8 3.6 3.6

FL cucumber (0.55 ppb) 3.4 0.5 0.7 0.8

CA tomato (0.13 ppb) 0.8 0.1 0.16 0.16

CA grapes (0.17 ppb) 1.0 0.17 0.40 0.2

FL cabbage (0.8 ppb) 4.8 0.8 0.45 0.7

CA lettuce (0.21 ppb) 1.3 0.2 0.04 0.4

ID potato (0.3 ppb) 1.8 0.3 0.4 0.4

RQ values in bold exceed the acute risk to listed species LOC of 0.05 or chronic risk LOC of 1.0. 

Acute RQ values for freshwater fish and invertebrates are based on an LC50= 0.163 ppb and 1.0 ppb, respectively. 

Chronic RQ values for freshwater fish and invertebrates are based on a 60-d NOAEC of 0.188 ppb and 21-d 

NOAEC of 0.224 ppb, respectively.

 

A summary of the risk quotients for estuarine/marine fish and aquatic invertebrates is presented 

in Table 5.2. For estuarine/marine fish, acute RQ values range from 0.03 to 0.83 and meet or 

exceed the acute risk to listed species LOC (0.05) and the non-listed species LOC (0.5) for 18

and 2 of the 22 exposure scenarios assessed, respectively. Chronic RQ values for 

estuarine/marine fish range from 0.05 to 2.5 and exceed the chronic risk to listed and non-listed 

species LOC of 1.0 for 9 of the 22 exposure scenarios assessed. For estuarine/marine aquatic 

invertebrates, acute RQ values range from <0.014 to <0.36. These acute RQ values are 

expressed as “less than” values because a definitive EC50 was not reached in the acute test for the 

most acutely sensitive estuarine/marine invertebrate species tested (EC50 was > 7.8 ppb). 

Therefore, only the upper bounds of the acute RQ values can be defined, assuming that the EC50

was actually 7.8 ppb. Based on the upper bound of the acute RQ values, 10 of the 22 acute RQ 

values could potentially exceed the acute risk to listed species LOC (0.05) and none exceed the 
Page 53 of 125 

acute risk to non-listed LOC of 0.5. However, the upper bound of these acute RQ values is 

relatively close to the listed species LOC of 0.05 (most are within a factor of 3). No chronic 

risks to estuarine/marine invertebrates are evident as none of the 22 exposure scenarios assessed 

resulted in RQ values that exceeded the LOC (1.0). 

Table 5.2. Risk Quotients for estuarine/marine fish and invertebrates 

Scenario/

Peak EEC 

Est/Mar. Fish 

Acute RQ

Est/Mar. 

Invertebrate 

Acute RQ

Est/Mar. 

Invertebrate 

Chronic RQ

Est/Mar. 

Fish Chronic

RQ

Aerial Application

CA citrus-150 ft buffer 

(0.21 ppb) 0.06 <0.027 0.03 0.26

FL citrus- 150 ft buffer 

(0.78 ppb) 0.23 <0.10 0.11 1.2

TX cotton (2.68 ppb) 0.80 <0.35 0.29 2.5

CA cotton (0.20 ppb) 0.06 <0.03 0.03 0.1

CA tomatoes (0.17 ppb) 0.05 <0.02 0.07 0.2

CA lettuce (0.11 ppb) 0.03 <0.014 0.05 0.4

FL cabbage (0.8 ppb) 0.24 <0.10 0.017 0.1

ID potato (0.31 ppb) 0.09 <0.04 0.05 0.5

Air Blast Application

NC apple (1.62 ppb) 0.48 <0.21 0.24 2.2

PA apple (1.24 ppb) 0.37 <0.16 0.2 2.2

OR apple (0.85 ppb) 0.25 <0.11 0.16 1.5

CA citrus (0.48 ppb) 0.14 <0.06 0.06 0.05

FL citrus (0.19 ppb) 0.14 <0.03 0.14 1.5

GA peach (0.14 ppb) 0.04 <0.018 0.14 1.2

GA pecan (1.44 ppb) 0.42 <0.18 0.17 1.7

Ground Application: Ground Boom, Air Curtain Sprayers, or other method

MS Cotton (2.8 ppb) 0.83 <0.36 0.38 1.7

FL cucumber (0.55 ppb) 0.16 <0.07 0.08 0.8

CA tomato (0.13 ppb) 0.04 <0.02 0.017 0.16

CA grapes (0.17 ppb) 0.05 <0.02 0.026 0.2

FL cabbage (0.8 ppb) 0.23 <0.10 0.05 0.7

CA lettuce (0.21 ppb) 0.06 <0.03 0.04 0.4

ID potato (0.3 ppb) 0.09 <0.04 0.04 0.4

RQ values in bold exceed the acute risk to listed species LOC of 0.05 or chronic risk LOC of 1.0. 

Acute RQ values for estuarine/marine fish and invertebrates are based on an LC50= 3.38 ppb for sheepshead minnow 

and an EC50 of >7.8 ppb for eastern oyster, respectively. Chronic RQ values for estuarine/marine fish and 

invertebrates are based on a 60-d NOAEC of 0.186 ppb for sheepshead minnow and 28-d NOAEC of 2.3 ppb for 

mysid shrimp, respectively.

Risk quotients for aquatic plants are provided in Table 5.3. For non-listed and listed vascular 

aquatic plants, risk quotients do not exceed the LOC of 1.0. The risk quotients are expressed as 

“less than” values for listed aquatic plants because the EC50 upon which they are based was nondefinitive (> 30 ppb). For non-vascular aquatic plants, RQ values range from 0.1 to 2.8 for nonlisted species and 0.1 to 5.6 for listed species, indicating risk to non-vascular plants for selected 

crop exposure scenarios. 
Page 54 of 125 

Table 5.3. Risk quotients for vascular and non-vascular aquatic plants

Scenario/

Peak EEC

Vascular 

aquatic plant 

RQ

Listed

Vascular

Aquatic Plant 

RQ

Non-Vascular 

Aquatic plant 

RQ

Listed NonVascular 

Plant RQ

Aerial Application

CA citrus-150 ft buffer 

(0.21 ppb) <0.006 0.006 0.2 0.4

FL citrus- 150 ft buffer (0.78 

ppb) <0.026 0.026 0.8 1.5

TX cotton (2.68 ppb) <0.089 0.089 2.7 5.4

CA cotton (0.20 ppb) <0.006 0.006 0.2 0.4

CA tomatoes (0.17 ppb) <0.006 0.006 0.2 0.3

CA lettuce (0.11 ppb) <0.003 0.003 0.1 0.2

FL cabbage (0.8 ppb) < 0.026 0.026 0.8 1.6

ID potato (0.31 ppb) < 0.01 0.01 0.3 0.6

Airblast Application

NC apple (1.62 ppb) < 0.054 0.054 1.6 3.2

PA apple (1.24 ppb) < 0.04 0.04 1.2 2.5

OR apple (0.85 ppb) < 0.026 0.026 0.8 1.7

CA citrus (0.48 ppb) < 0.016 0.016 0.5 1.0

FL citrus (0.19 ppb) < 0.006 0.006 0.2 0.4

GA peach (0.14 ppb) < 0.005 0.005 0.1 0.3

GA pecan (1.44 ppb) < 0.05 0.05 1.4 2.9

Ground Application

MS Cotton (2.8 ppb) <0.09 0.09 2.8 5.6

FL cucumber (0.55 ppb) < 0.018 0.018 0.5 1.1

CA tomato (0.13 ppb) < 0.004 0.004 0.1 0.3

CA grapes (0.17 ppb) < 0.006 0.006 0.17 0.3

FL cabbage (0.8 ppb) < 0.026 0.026 0.8 1.6

CA lettuce (0.21 ppb) < 0.006 0.006 0.2 0.4

ID potato (0.3 ppb) < 0.01 0.01 0.3 0.6

RQ values for vascular aquatic plants determined using an EC50 of >30 ppb (non-listed) and NOAEC of 30 ppb 

(listed). RQ values for non-vascular aquatic plants determined using an EC50 of 1.0 ppb (non-listed) and 0.50 ppb 

(listed). RQ values in bold exceed the LOC of 1.0 for plants.

5.1.2 Non-target Terrestrial Animals (Terrestrial Diet)

Birds

For the technical grade active ingredient, the lowest acute oral toxicity endpoint was an ED50 of 

58 mg a.i./kg bw for the zebra finch and a dietary LC50 of 1348 ppm based the bobwhite quail.

Avian acute RQ values are shown in Table 5.4 for each proposed application scenario. 

Considering all the size classes and dietary categories, acute oral and diet-based RQ values range 
Page 55 of 125 

from <0.01 to 2.5. On an acute dietary basis, only 1 RQ value meets or exceeds the avian acute 

risk to endangered species LOC of 0.1 (curcurbits, short grass). On an acute dose basis, acute 

RQ values exceed the endangered species LOC (0.1) for all exposure scenarios assessed and for 

most of the food items for small (20g), medium (100g), and large (1000g) size birds. Acute oral 

RQ values exceeded the acute risk to non-listed avian LOC (0.5) for most dietary categories for 

small birds (20g) and primarily just for short grass and broadleaf plants for medium size birds 

(100g). None of the acute oral RQ values exceeded the acute risk to non-listed species LOC 

(0.5) for large birds (1000g). 

Table 5.4 Avian Acute Dietary or Oral Dose-Based Risk Quotients

Feeding Category Dietary RQ Dose-Based RQ 

Small

(20 g)

Medium

(100 g)

Large

(1000 g)

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, oriental pear, stone 

fruit and tree nuts

2 apps @ 0.27 lb a.i./acre (14-day interval)

Short grass 0.08 2.1 0.93 0.29

Tall grass 0.04 0.95 0.43 0.13

Broadleaf plants 0.05 1.2 0.52 0.17

Fruits/pods 0.01 0.1 0.06 0.02

Arthropods 0.03 0.81 0.36 0.12

Seeds 0.01 0.03 0.01 <0.01

Cucurbits (4 apps at 0.21 lb a.i./A, 14-d interval)

Short grass 0.10 2.5 1.1 0.36

Tall grass 0.05 1.2 0.52 0.17

Broadleaf plants 0.06 1.4 0.64 0.20

Fruits/pods 0.01 0.16 0.07 0.02

Arthropods 0.04 0.99 0.44 0.14

Seeds 0.01 0.04 0.02 0.01

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton (2 apps at 0.21 lb a.i./A, 

14-d interval)

Short grass 0.07 1.6 0.72 0.23

Tall grass 0.03 0.74 0.33 0.10

Broadleaf plants 0.04 0.91 0.41 0.13

Fruits/pods <0.01 0.10 0.05 0.01

Arthropods 0.03 0.63 0.28 0.09

Seeds <0.01 0.02 0.01 <0.01

Acute avian diet and dose-based RQ values are based on EEC estimates (Table 3.6) and a dietary LC50 of 1348 ppm 

(bobwhite quail) and an acute oral ED50 of 58 mg ai/kg bw (zebra finch), respectively. Acute RQ values shown in 

bold meet or exceed the acute risk to listed species LOC of 0.1. 

Chronic risk quotients for birds could not be expressed on a definitive basis because a NOAEC 

was not reached in the avian reproductive study with the most sensitive species tested (LOAEC = 

9.7 ppm at the lowest test concentration for egg laying). Therefore, in order to determine if the 

avian chronic LOC of 1.0 is exceeded by the proposed uses, non-definitive (“greater than”) RQ 

values were calculated using a NOAEC of <9.7 ppm in the diet. These “greater than” RQ values 

provide the lower bound of the chronic RQ and can be used to determine if the chronic LOC is 

exceeded (but not precisely by how much it is exceeded). Results from this comparison are 

provided in Table 5.5 and range from >0.6 to >14.4. These non-definitive RQ values indicate 

the potential for chronic risk to avian species for all assessed uses and dietary categories except 

possibly fruits and pods. Given the proximity of the non-definitive RQ for fruits and pods to the 
Page 56 of 125 

LOC of 1.0 in combination with the use of a LOAEC to calculate the RQ value, there is 

reasonable potential for chronic risks to occur if a definitive NOAEC was available from the 

avian reproduction study. 

Table 5.5 Avian Chronic Avian Diet-Based Risk Quotients 

Diet Category Chronic RQ

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, 

oriental pear, stone fruit and tree nuts

(2 apps @ 0.27 lb a.i./acre 14-day interval)

Short grass > 11.7

Tall grass > 5.4

Broadleaf plants > 6.6

Fruits/pods > 0.7 

Arthropods >4.6

Cucurbits (4 apps at 0.21 lb a.i./A, 14-d interval)

Short grass > 14.4

Tall grass > 6.6

Broadleaf plants > 8.1

Fruits/pods > 0.9

Arthropods > 5.6

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton (2 apps 

at 0.21 lb a.i./A, 14-d interval)

Short grass > 9.1

Tall grass > 4.2

Broadleaf plants > 5.1

Fruits/pods > 0.6

Arthropods > 3.6

Chronic avian diet-based RQ values are based on EEC estimates (Table 3.6) and a dietary NOAEC of < 9.7 ppm, 

which yield non-definitive (“>”) RQ values. The chronic RQ values shown in bold exceed the avian chronic risk to 

listed and non-listed species LOC of 1. 

Mammals

Acute risk quotients for mammals were calculated using the acute oral rat study submitted for the 

technical grade active ingredient. Acute dose-based mammalian RQs are shown in Table 5.6 for 

all proposed use scenarios. Considering all the size classes and dietary categories, acute dosebased RQ values range from <0.01 to 0.25, which indicates that none exceed the acute risk to 

non-listed species LOC of 0.5 for mammals. Mammalian acute RQ values generally exceeded 

the acute risk to listed species LOC (0.1) for short grass, tall grass, and broadleaf plants for small 

(15g) and medium (35g) size mammals; however, the RQ values were within a factor of two of 

this LOC. 
Page 57 of 125 

Table 5.6. Acute mammalian dose-based risk quotients 

Feeding Category

Dose-based Risk Quotients

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, oriental pear, stone fruit and 

tree nuts

2 apps @ 0.27 lb a.i./acre (14-day interval)

Short grass 0.21 0.18 0.09

Tall grass 0.09 0.08 0.04

Broadleaf plants 0.12 0.10 0.05

Fruits/pods 0.01 0.01 0.01

Arthropods 0.08 0.07 0.04

Seeds <0.01 <0.01 <0.01

Cucurbits

4 apps @ 0.21 lb a.i./acre (14-day interval)

Short grass 0.25 0.22 0.12

Tall grass 0.12 0.10 0.05

Broadleaf plants 0.14 0.12 0.07

Fruits/pods 0.02 0.01 0.01

Arthropods 0.10 0.08 0.05

Seeds <0.01 <0.01 <0.01

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton

2 apps @ 0.21 lb a.i./acre (14-day interval)

Short grass 0.16 0.14 0.07

Tall grass 0.07 0.06 0.03

Broadleaf plants 0.09 0.08 0.04

Fruits/pods 0.01 0.01 0.00

arthropods 0.06 0.05 0.03

Seeds <0.01 <0.01 <0.01

Acute mammalian dose-based RQ values are based on EEC estimates (Table 3.7) and an acute oral LD50 of 239 

mg/kg bw for the laboratory rat. RQ values shown in bold exceed the mammalian acute risk to listed species LOC

of 0.1. 

In the submitted one-generation rat reproduction study with dietary tolfenpyrad exposure, the 

NOAEL was 0.86 mg a.i./kg-bw/day for males. Chronic RQs are shown in Table 5.5 below. 

Considering all of the crop scenarios and dietary categories, chronic mammalian RQ values 

range from 0.37 to 70.4. Chronic risk to mammals (small, medium and large) is indicated for all 

crop exposure scenarios modeled and for all dietary categories except seeds.

Table 5.5. Chronic mammalian dietary and dose-based risk quotients 

Feeding Category Dietary-based 

Risk Quotients

Dose-based Risk Quotients

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Citrus fruit, grapes, apples, crabapples, loquat, mayhaw, quince, pear, oriental pear, stone fruit and 

tree nuts

(2 apps at 0.27 lb a.i./acre, 14-day interval)

Short grass 7.6 57.5 49.1 26.3

Tall grass 3.5 26.3 22.5 12.1

Broadleaf plants 4.3 32.3 27.6 14.8

Fruits/pods 0.47 3.6 3.1 1.6

Arthropods 3.0 22.5 19.2 10.3

Seeds 0.47 0.80 0.68 0.37

Cucurbits (4 apps at 0.21 lb a.i./acre, 14-day interval)
Page 58 of 125 

Feeding Category Dietary-based 

Risk Quotients

Dose-based Risk Quotients

Small

(15 g)

Medium

(35 g)

Large

(1000 g)

Short grass 9.3 70.4 60.1 32.2

Tall grass 4.3 32.3 27.6 14.8

Broadleaf plants 5.2 39.6 33.8 18.1

Fruits/pods 0.58 4.4 3.8 2.0

Arthropods 3.6 27.6 23.5 12.6

Seeds 0.58 0.98 0.83 0.45

Leafy vegetables, potatoes, Brassica, fruiting vegetables and cotton (2 apps @ 0.21 lb a.i./acre

14-day interval)

Short grass 5.9 44.7 38.2 20.5

Tall grass 2.7 20.5 17.5 9.4

Broadleaf plants 3.3 25.1 21.5 11.5

Fruits/pods 0.37 2.8 2.4 1.3

Arthropods 2.3 17.5 15.0 8.0

Seeds 0.37 0.62 0.53 0.28

Chronic mammalian diet-based RQ values are based on EEC estimates (Table 3.7) and a dietary NOAEL of was 

0.86 mg a.i./kg-bw/day (15 ppm diet) for male rats. The chronic RQ values shown in bold exceed the mammalian 

chronic risk to listed and non-listed species LOC of 1. 

5.1.3 Non-target Terrestrial Animals (Aquatic Prey)

Results from the KABAM aquatic bioaccumulation assessment regarding the potential for risks 

to piscivorous mammals and birds are shown in Table 5.6 for the crop exposure scenario 

producing the highest EECs (TX Cotton). Complete model results, input parameters and 

intermediate calculations are provided in Appendix E. As indicated below, the potential for 

chronic risks to piscivorous wildlife is indicated for three representative mammal feeding guilds 

(fog/water shrew, rice rate/star-nosed mole, and small river otter) and is very close to the chronic 

LOC of 1.0 for the remaining representative mammalian species. Risks to piscivorous birds are 

not indicated; however it is noted that the chronic NOAEC used was < 9.7 ppm (diet) based on 

the LOAEL from the avian reproduction study. Therefore, chronic risks to piscivorous birds 

may be indicates should the actual NOAEL be lower than the LOAEL by approximately a factor 

of two.

Table 5.6. Calculation of RQ values for mammals and birds consuming fish contaminated by 

Tolfenpyrad (TX Cotton).

Wildlife Species

Acute Chronic

Dose Based Dietary Based Dose Based Dietary Based

Mammalian

fog/water shrew 0.010 N/A 2.8 0.50

rice rat/star-nosed mole 0.008 N/A 2.3 0.34

small mink 0.003 N/A 0.87 0.14

large mink 0.003 N/A 0.96 0.14

small river otter 0.004 N/A 1.0 0.14

large river otter 0.003 N/A 0.80 0.10

Avian

sandpipers 0.095 0.004 N/A >0.60

cranes 0.005 0.004 N/A >0.57

rails 0.045 0.004 N/A >0.61
Page 59 of 125 

Wildlife Species

Acute Chronic

Dose Based Dietary Based Dose Based Dietary Based

herons 0.007 0.004 N/A >0.56

small osprey 0.004 0.002 N/A >0.25

white pelican 0.001 0.001 N/A >0.18

5.1.4 Terrestrial and Semi-aquatic Plants

Terrestrial and semi-aquatic plants may be exposed to pesticides from runoff and spray drift. 

Semi-aquatic plants are those that inhabit low-lying wet areas that may be dry at certain times of 

the year. EECs for terrestrial and semi-aquatic plants are derived for areas adjacent to the 

treatment site. Acute RQs for terrestrial plants are derived by dividing the EEC by the EC25 from 

seedling emergence and vegetative vigor toxicity tests. Acute RQs for listed plant species are 

calculated by dividing the EEC by the NOAEC (if not available, an EC05 is used) value from 

toxicity tests.

Terrestrial plant EECs and toxicity endpoints are provided in Tables 3.11 and 4.7, respectively. 

Because no inhibitory effects greater than 25% were observed in either the vegetative vigor or 

seedling emergence studies with tolfenpyrad 15% SC, RQs were not calculated for non-listed 

species. For listed species of monocots, the NOAEC of 0.265 lbs a.i./acre was used to calculate 

RQs. For listed species of dicots, a NOAEC of 0.265 lbs a.i./acre derived from the submitted 

vegetative vigor study was used to calculate the potential risk from spray drift exposure only. 

TerrPlant v1.2.2 (Appendix C) and risk quotient (RQs) are summarized in Table 5.7.

Based on a single application, none of the RQs exceeded the LOC for listed terrestrial plants.

Table 5.7. Tolfenpyrad (RQ) values for plants in dry and semi-aquatic areas

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Only

Monocot Listed <0.1 <0.1 <0.1

Dicot Non-listed <0.1 <0.1 <0.1

Dicot Listed Could not be 

determined

Could not be 

determined <0.1

* Based on the maximum proposed application rate –0.27 lbs a.i./acre. Aerial and ground spray application 

scenarios resulted in no differences in risk quotient calculations.

5.1.5 Non-Target Insect Pollinators

In September 2012, the USEPA Office of Pesticide Programs published its draft Pollinator Risk 

Assessment Framework for review by the FIFRA Scientific Advisory Panel.1 In this framework, 

a tiered approach is used for assessing risks to bees from different routes of exposure to 

pesticides (direct contact via interception of spray droplet and oral exposure via consumption of 

contaminated pollen and nectar). For tolfenpyrad, both contact and oral routes of exposure are 

relevant since it is proposed for aerial application to crops with no proposed restriction of 

 

1

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPP-2012-0543-0004
Page 60 of 125 

application during blooming periods of crops. As risks are identified in lower tiers, additional 

refinements and data are considered in higher tiers.

Tier 1 of the draft risk assessment framework consists of a screening-level assessment that 

requires minimal data but is conservative in the estimation of potential exposure. For dietary 

exposure to pesticides, the Tier 1 approach uses the upper-bound residue for tall grass predicted 

by the T-REX model (v. 1.5.1). This is the same model used for establishing screening-level 

exposures to terrestrial vertebrates. The upper bound residue predicted for tall grass (110 mg 

a.i./kg per lb a.i./A) is considered a reasonably conservative estimate of the upper bound residues 

of pesticides in pollen and nectar, as detailed in the Agency’s Risk Assessment Framework 

White Paper. This upper bound residue value is then converted to a dietary dose received by 

adult and larval worker bees using pollen and nectar consumption rates for these two life stages, 

which are 292 and 120 mg/day, respectively. These consumption estimates represent central 

tendency estimates for the caste of honey bees which are expected to be experience the greatest 

exposure via the dietary route. Consequently, the dietary based exposure value for larvae is 13 

μg a.i./bee per 1 lb a.i./A and the value for adults is 32 μg a.i./bee per 1 lb a.i./A. Estimated 

pesticide exposure values are then scaled to a pesticide-specific application rate by multiplying 

by the application rate. Finally, the pesticide-specific dietary exposure estimate is divided by 

the acute oral LD50 to determine the acute oral RQ. This acute RQ is compared to an acute risk 

LOC of 0.4 determined specifically for honey bees.

In order to quantify contact exposures due to direct spray, the proposed upper bound value is 2.7 

μg a.i./bee per 1 lb a.i./A. This value is based on data published by Koch and Weisser 1997, who 

measured residues on bees following a series of spray applications. As with oral exposure, the 

dose per bee on a 1 lb a.i./A basis is scaled to a pesticide-specific application rate by multiplying 

by the application rate. The acute contact RQ is determined by dividing this scaled pesticide 

contact dose by the acute contact LD50 and compared to the same LOC of 0.4 for identifying 

acute risk concerns.

Results from the Tier 1 acute oral and contact screening risk assessment are provided in Table 

5.8. Since the Tier 1 acute RQ values exceed the acute risk LOC of 0.4, the potential for acute 

risk to honey bees is identified. These results indicate that additional refinements to the Tier 1 

risk assessment may be appropriate, including use of chemical-specific residues on pollen and 

nectar and possibly consideration of exposure and effects at the whole colony level (Tier 2 

assessment). They also indicate that practices to mitigation exposure to bees (e.g., restricting 

application during bloom for oral exposure) may be necessary to reduce acute risk to bees.
Page 61 of 125 

Table 5.8. Tier 1 acute contact and dietary risk quotients for honey bees 

Life 

Stage Exposure Type Dose (μg a.i./beeper 1 lb a.i./A)(1)

Tolfenpyrad Dose

for Max Application 

Rate (μg a.i./bee

per 0.27 lb a.i./A)

Acute 

RQ)(2)(3)

Chronic 

RQ)(3)

Adult Diet (nectar + pollen) 32 8.64 23 n.a.

Adult Direct contact 2.7 0.729 1.6 n.a.

(1)

Source: USEPA 2012. Draft Pollinator Risk Assessment Framework

(2) Based on a 48-h acute contact LD50 of 0.47 μg ai/bee for TGAI and acute oral LD50 of 0.37 μg ai/bee 

for TGAI (MRID 48250432).

(3) Bolded value exceeds the acute risk LOC of 0.4

5.2 Risk Description

A screening-level risk assessment, based on the proposed uses of tolfenpyrad, suggests that 

predicted levels of tolfenpyrad in the environment, when compared with the most sensitive 

toxicity values for a given taxa, may result in direct adverse effects to birds, mammals, fish, 

aquatic invertebrates and nonvascular aquatic plants. Risks to aquatic vascular plants and 

terrestrial plants are below Agency levels of concern. Tolfenpyrad is also highly toxic to nontarget pollinator insects and possibly other terrestrial invertebrates from contact, ingestion or 

foliar residue exposures. The following discussion is intended to characterize the previous risk 

estimation of tolfenpyrad in the context of all available information and considers the sensitivity 

and uncertainty associated with the risk estimation methods and available data. 

5.2.1 Risks of Tolfenpyrad to Aquatic Organisms

The Tier II model Pesticide Root Zone Model (PRZM v3.12.2) linked with EXposure Analysis 

Modeling System (EXAMS v2.98.4.6) via the model shell PRZM/EXAMS (PE v5.0, Nov. 15, 

2006) was run to estimate baseline-level exposures for grape scenario. The PRZM model 

simulates pesticide movement and transformation on and across the agricultural field resulting 

from crop applications. The EXAMS model simulates pesticide loading via runoff, erosion, and 

spray drift assuming a “standard” 1-ha pond, 2-m deep (20,000 m3) with no outlet that borders a 

10-ha treated field. Simulations are run for multiple (usually 30) years, and the Agency 

estimates peak and running mean values that are expected once every ten years based on the 

daily values generated during the simulation. The coupled PE models and users manuals are 

available from the U.S. Environmental Protection Agency Water Models web-page (U.S. EPA, 

2011).

Exposure estimates generated using this “standard” pond are intended to represent a wide variety 

of vulnerable water bodies that occur at the top of watersheds including prairie pot holes, playa 

lakes, wetlands, vernal pools, man-made and natural ponds, and intermittent and first-order 

streams. As a group, there are factors that make these water bodies more or less vulnerable than 

the standard surrogate pond. Static water bodies that have larger ratios of pesticide-treated 

drainage area to water body volume would be expected to have higher peak EECs than the 

standard pond. These water bodies will be either smaller in size or have large drainage areas. 

Smaller water bodies have limited storage capacity and thus may overflow and carry pesticide in 

the discharge, whereas the standard pond has no discharge. As watershed size increases, it 
Page 62 of 125 

becomes increasingly unlikely that the entire watershed is planted with a non-major single crop 

that is all treated simultaneously with the pesticide. Headwater streams can also have peak 

concentrations higher than the standard pond, but they likely persist for only short periods of 

time and are then carried and dissipated downstream. The surface water and pore water EECs 

calculated for aquatic organism risk assessment are provided in Tables 3.4 and 3.5. A discussion 

of the risk assessment for various taxonomic groups of aquatic organisms is provided below.

Fish and Aquatic –Phase Amphibians 

The potential for acute risks to listed and non-listed freshwater and estuarine/marine fish is 

indicated for the proposed uses of tolfenpyrad. Specifically, acute RQ values for freshwater fish 

(range: 0.7 -17) exceed the acute risk to listed and non-listed species LOC of 0.05 and 0.5, 

respectively, for all 22 crop exposure scenarios modeled. These RQ values are based on 1 in 10 

year peak EECs for tolfenpyrad that range from 0.11 and 2.8 μg a.i./L, respectively and an acute 

LC50 of 0.163 μg a.i./L for rainbow trout exposed to TGAI (the most acutely sensitive of the 

three species tested). In considering the acute LC50 values for the other two freshwater fish 

species (0.94 and 3.2 μg a.i./L for bluegill and carp, respectively), the range in acute sensitivity

for tested freshwater fish is about 30X. However, acute risk would still be expected for some 

exposure scenarios even with these less acutely sensitive fish species. For estuarine/marine fish, 

the magnitude of the acute RQ values are lower than those for freshwater fish (range: 0.03-0.83) 

due the lower sensitivity of the single tested species (sheepshead minnow; LC50 = 3.38 μg a.i./L). 

These acute RQ values exceeded the acute risk to listed and non-listed species LOC of 0.05 and 

0.5, respectively, in 18 and two of the 22 crop exposure scenarios modeled. The crop exposure 

scenarios that yield the highest acute risk potential to fish include TX cotton, NC apple, PA apple 

OR apple, GA pecan, and MS cotton, with acute RQs exceeding the acute risk to FW fish LOC 

of 0.5 by 10X or higher. It is noted that all EECs determined for aerial application include a 

150ft buffer.

The potential for chronic risk to freshwater and estuarine/marine fish from the proposed uses of 

tolfenpyrad is also indicated for 9 of the 22 crop exposure scenarios modeled for each taxonomic 

group. Chronic RQ values range from 0.05 to 3.6 for freshwater fish and from 0.05 to 2.5 for 

estuarine/marine fish. It is worthy to note that the chronic early life stage NOAEC for freshwater 

fish (0.188 μg a.i. with fathead minnow) is actually somewhat higher than the 96-h LC50 of 0.114 

μg a.i./L for rainbow trout. The reason for this similarity between the acute and chronic 

endpoints for freshwater fish is not known with certainty, but is likely related to different species 

upon which the acute and chronic toxicity endpoints are based. It is noted that rainbow trout are 

more acutely sensitive than warm water fish (bluegill, carp) by 9X and 30X, respectively. 

Therefore, it is reasonable to expect that if the chronic toxicity of tolfenpyrad were also 

determined on rainbow trout, a lower NOAEC would have been achieved. Another possible 

reason for this similarity in acute and chronic toxicological endpoints may relate to the study 

limitations associated with the chronic NOAEC of 0.188 μg a.i./L with fathead minnow. 

Specifically, results from growth measurements were deemed unreliable for that study and the 

NOAEC was based on survival only (see Section 4.1). However, the freshwater fish full life 

cycle NOAEC for the same species (0.189 μg a.i./L based on reductions in survival) was nearly 

identical to the ELS NOAEC (0.188 μg a.i./L). Furthermore, a nearly identical NOAEC was 
Page 63 of 125 

observed with the sheepshead minnow (0.186 μg a.i./L based on reductions in growth). All three 

chronic toxicity studies were based on total radioactive residues (TRR) and did not directly 

measure parent chemical in exposure solutions. As a result, it is possible that actual freshwater 

and estuarine/marine NOAEC values for parent tolfenpyrad may be lower than those based on 

TRR if parent chemical was undergoing degradation during the study. As discussed previously 

in Section 4.1, the toxicity of the major transformation products of tolfenpyrad to freshwater fish 

(PCA, PC-TA, PT(A)-4OH and PAM) was three orders of magnitude less than parent 

tolfenpyrad.

Aquatic Invertebrates

The potential for acute risks to listed and non-listed freshwater invertebrates is indicated for the 

proposed uses of tolfenpyrad. Specifically, freshwater invertebrate acute RQ values range from 

0.1 to 2.8 and exceed the acute risk to listed species LOC (0.05) and non-listed species LOC 

(0.5) in 22 and 11 exposure scenarios, respectively. For estuarine/marine invertebrates, a 

potential for acute risk to listed invertebrates was identified (RQ range: <0.014 to <0.36). 

However, acute risks to non-listed invertebrates were not evident since acute RQ values were 

below the non-listed species LOC of 0.5. The potential for acute risk to listed estuarine/marine 

invertebrates is much less certain compared to freshwater invertebrates because the acute EC50 

value upon which the estuarine/marine RQ values are based is a non-definitive value (> 7.8 μg 

a.i./L for eastern oyster). Thus, only the upper bound of the acute RQ values could be 

determined by basing it on the maximum concentration tested in this study (7.8 μg a.i./L). At the 

highest and second most highest test concentrations, 37 % and 44% inhibition in shell deposition 

occurred. These observations suggest that the actual EC50 value may be relatively close to the 

highest test concentration of 7.8 μg a.i./L. For mysid shrimp, the EC50 was > 12 μg a.i./L.

Chronic risks to freshwater invertebrates are evident in 10 of the 22 exposure scenarios where 

RQ values meet or exceed the LOC of 1.0 and range from 0.04 to 3.6. These chronic RQ values 

are based NOAEC of 0.244 μg a.i./L determined for reproductive effects on the cladoceran, D. 

magna. Furthermore, chronic EECs exceed the LOAEC of 0.482 μg a.i./L from this study, with 

reflects the onset of significant reductions in the number of offspring. For estuarine/marine 

invertebrates, chronic risks were not evident for any of the 22 exposure scenarios evaluated.

For freshwater benthic invertebrates, a pore water NOAEC of 0.0288 μg a.i./L was determined 

for a 28-d exposure of the midge, C. riparius. Importantly, no significant adverse effects on 

emergence or development rate were observed in any exposure concentration tested in this study. 

Furthermore, effects on reproduction were not included, which is required for USEPA chronic 

life cycle sediment toxicity testing. All but four of the 21-d EECs in pore water (Table 3.5)

exceed this unbounded NOAEC of 0.0288 μg a.i./L, with the maximum EEC exceeding by a 

factor of 10. Therefore, there is a potential for chronic risks to benthic aquatic invertebrates for 

the proposed tolfenpyrad uses; however, risk estimation is highly uncertain due to the 

aforementioned limitations of the sediment toxicity study.
Page 64 of 125 

Aquatic Plants

The submitted tolfenpyrad technical study for Lemna gibba indicates that tolfenpyrad is not toxic 

aquatic vascular plants up to the highest concentration tested, 30 μg a.i./L (MRID 48250436). 

As a result, risk quotients do not exceed the LOC of 1.0 for non-listed and listed vascular aquatic 

plants and the potential risk to aquatic vascular plants is considered low. It is noted that the 

unbounded NOAEC of 30 μg a.i./L is within a factor of two of the reported solubility of 

tolfenpyrad in water (87 μg a.i./L). 

For non-vascular aquatic plants, RQ values range from 0.1 to 2.8 for non-listed species and 0.1 

to 5.6 for listed species, indicating risk to non-vascular plants for selected crop exposure 

scenarios. Phytotoxic effects to algae occurred at concentrations ranging from 1 to greater than 

87 μg a.i./L. 

Vegetative Buffers

It should be recognized that the proposed tolfenpyrad labels contain a statement that includes 

“constructing and maintaining a minimum 15-foot wide vegetative filter strip of grass or 

the permanent vegetation between field edge and down gradient aquatic habitat”. At this 

time, however, EFED does not have standard, approved models for evaluating the effect of 

vegetative buffers on aquatic EECs. Furthermore, the performance of the vegetative buffer in 

reducing aquatic exposure to pesticides is expected to vary depending on the vegetation type, 

density, topography, soil characteristics, and maintenance of the buffer. Therefore, acute and 

chronic risks to aquatic organisms may be lower to the extent that the 15-foot vegetative buffers 

reduce pesticide loadings to aquatic ecosystems.

5.2.2 Risks of Tolfenpyrad to Terrestrial Organisms

Birds, Terrestrial-phase Amphibians and Reptiles

Acute risk to birds (and by extension, terrestrial-phase amphibians and reptiles) are indicted on 

the basis of acute oral dose-based exposures, with RQ values ranging from <0.01 to 2.5 (Table 

5.4). These RQ values are based on the most sensitive avian acute toxicity value (ED50 of 58 mg 

a.i./kg-bw for zebra finch based on dose-dependent increase in regurgitation. No mortality 

occurred for finch which did not regurgitate the dose during this study and all fish appeared 

asymptomatic by the end of the study. Therefore, it seems likely that the actual LD50 for finch 

would be higher than the ED50 based on regurgitation; however how much higher is uncertain. 

The next highest acute toxicity value is for bobwhite quail (87 mg a.i./kg-bw). Although there is 

uncertainty associated with the acute oral passerine toxicity value because it is based on a nonlethal (but ecologically relevant) response, acute dose-based RQ values for bobwhite quail are 

nearly equivalent to those based on the finch ED50, thus rendering this uncertainty of little 

consequence to the acute avian risk conclusions. On a dietary acute exposure basis, only one RQ 

value meets or exceeds the avian acute risk to endangered species LOC of 0.1 (curcurbits, short 

grass). 
Page 65 of 125 

Chronic risk to birds is indicated based on a comparison of the peak EECs on terrestrial food 

items and non-definitive (“less than”) avian reproduction NOAEC of < 9.7 ppm in diet (chronic 

RQ range: >0.6 to >14.4). These non-definitive RQ values indicate the potential for chronic risk 

to avian species for all assessed uses and dietary categories except possibly fruits and pods. It is 

noted that the predicted upper bound residues of tolfenpyrad on short grass, tall grass, broadleaf 

plants and arthropods exceed the chronic avian LOAEC of 9.7 ppm in the diet for the first 176, 

137, 146 and 129 days of the T-REX simulation for the 4 x 0.21 lb a.i./A application rate for 

cucurbits (Figure 5.1). Furthermore, even when mean predicted residues on terrestrial food 

items are considered, the predicted concentrations are approximately 1/3 those based on the 

upper bound residue estimates and thus, still exceed the chronic avian LOAEL of 9.7 for all 

proposed uses and with most dietary categories. One possible refinement to the avian risk 

estimation is the use of a chemical-specific foliar dissipation half life instead of a default half life 

of 35-d. If the tolfenpyrad foliar half life was substantially shorter than the default value of 35 

days, then the number of days residues exceed the avian LOAEL would be reduced. However, 

chronic risk concerns would still occur since the peak residue from a single application exceeds 

the avian LOAEL. 

Figure 5.1. T-REX-predicted upper bound concentrations of tolfenpyrad on terrestrial food items 

based on cucurbits (4 x 0.21 lb a.i./A @ 14-d interval) in relation to avian acute and chronic dietary 

toxicity levels of concern

Avian chronic LOAEL of 9.7 ppm
Page 66 of 125 

Acute risks to piscivorous birds are not indicated based on bioaccumulation modeling with 

KABAM in combination with measured uptake and elimination rates of tolfenpyrad in fish using 

the exposure scenario producing the greatest aquatic EECs. The lower bound of chronic RQ

values for piscivorous birds does not exceed the chronic LOC; however, given its close 

proximity to the chronic LOC (within a factor of two), the potential for chronic risk cannot be 

discounted because a definitive NOAEC was not available from this study. 

Mammals

None of the acute-dose based RQ values derived using T-REX exceed the acute risk to non-listed 

LOC of 0.5 for mammals (Table 5.5). However, the acute dose-based RQ exceed the listed 

species LOC of 0.1 by up to a factor of 2.5 (small mammals consuming short grass) indicating 

potential acute risk to listed mammals (mostly small and medium size categories). 

The potential for chronic risks to mammals is much higher compared to acute risks, with chronic 

dose-based RQ values ranging from 0.37 to 70.4, depending on mammalian size class and 

dietary item. Chronic risk to mammals (small, medium and large) is indicated for all crop 

exposure scenarios modeled and for all dietary categories except seeds. The chronic mammalian 

dose-based RQ values are derived using a chronic mammalian NOAEL of 0.86 mg a.i./kgbw/day for male rats. On a chronic dietary basis, chronic risk is also indicated with RQ values 

ranging from 0.37 to 9.3. The overall potential for chronic risks to mammals is not expected to 

be sensitive to the use of a default foliar half life (35-days) or upper bound estimates of dietary 

residues (Figure 5.2).
Page 67 of 125 

Figure 5.2. T-REX-predicted upper bound concentrations of tolfenpyrad on terrestrial food items 

based on cucurbits (4 x 0.21 lb a.i./A @ 14-d interval) in relation to mammalian acute and chronic 

dietary toxicity levels of concern

For piscivorous mammals, acute risks are not indicated based on KABAM modeling (Table 5.6). 

However, chronic risks are indicate on a dose-basis, with RQ values ranging from 0.8 to 2.8 

depending on species. The higher RQ values are indicated for species that consume a substantial 

portion of their aquatic diet from the lower portions of the aquatic food web (e.g., benthic 

invertebrates being consumed by the fog/water shrew and rice rat/star-nose mole). Since data 

were not available from which to derive a tolfenpyrad metabolism rate constant for aquatic 

invertebrates, a default value of zero was used. This resulted in the prediction of higher residues 

of tolfenpyrad at the lower portion of the aquatic food webs compared to fish. If tolfenpyrad 

metabolism in aquatic invertebrates is similar to that in fish, then chronic risks to these species 

would be lower. 

Terrestrial Plants

Risk to listed terrestrial plants is not indicated based on the maximum single application rates, as 

RQ values did not exceed the list and non-listed LOC for terrestrial plants. Because no 

0.0

50.0

100.0

150.0

200.0

250.0

300.0

350.0

0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 320 340 360 Concentration (mg ai/kg dietary item)

Days

Terrestrial Residues (upper bound estimates)

vs

Mammalian Herbivore/Insectivore LOCs (as dietary concentrations

Short Grass Tall Grass Broadleaf plants

Fruits/pods/seeds Arthropods Chronic LOC

15 g Mammal Acute LOC 35 g Mammal Acute LOC 1000 g Mammal Acute LOC

15 g Endangered Mammal Acute LOC 35 g Endangered Mammal Acute LOC 1000 g Endangered Mammal Acute LOC

Time (days)
Page 68 of 125 

inhibitory effects greater than 25% were observed in either the vegetative vigor or seedling 

emergence studies with tolfenpyrad 15% SC, RQs were not calculated for non-listed species. For 

listed species of monocots, the NOAEC of 0.265 lbs a.i./acre was used to calculate RQs. For 

listed species of dicots, a NOAEC of 0.265 lbs a.i./acre derived from the submitted vegetative 

vigor study was used to calculate the potential risk from spray drift exposure only. TerrPlant 

v1.2.2 (Appendix C) and risk quotient (RQs) are summarized in Table 5.7.

6.0 Description of Assumptions and Limitations 

6.1 Assumptions and Limitations Related to Exposure for all Taxa

Though there are a number of areas of uncertainty in the aquatic and terrestrial risk assessments, 

many of the predicted environmental exposure levels do exceed the observed toxicity levels for 

many of the surrogate terrestrial and aquatic species tested to date. Protective chronic levels of 

concern are exceeded for single as well as multiple application scenarios. 

This screening-level risk assessment relies on labeled statements of the maximum rate of 

tolfenpyrad application, the maximum number of applications, and the shortest interval between 

applications. Actual usage in the field may vary dependent on pest abundance.

6.2 Assumptions and Limitations Related to Exposure for Terrestrial Species

Due to very low chronic effect levels for both avian species tested, there is concern that dermal 

and inhalation exposure to direct spray and dietary ingestion of residues on food matter could 

lead to reproductive effects. Many species have been observed to nest or raise broods in citrus 

and other types of fruit orchards. Young in nests are particularly susceptible in that they cannot 

leave the area. Adults may take flight at the sound of application equipment if there is adequate 

warning. See appendix I for listing of species that have been observed nesting in orchards.

Direct contact or oral ingestion for pollinators is also a major potential exposure route for crops 

such as almonds which are dependent on the pollination. Whether these taxa are exposed is 

dependent on whether infestations of target pests requiring treatment occur in early spring 

months or bloom periods.

Chemical half-life used in terrestrial exposure modeling

In the absence of actual foliar half-life data, an assumption of 35 days was used for the terrestrial 

exposure modeling for avian and mammalian species. This default is based on the highest 

reported half-life value (36.9 days) for foliar dissipation data for pesticides, as reported by Willis 

and McDowell (1987). 

Likelihood of direct or indirect exposure

It is assumed that certain terrestrial species will be present in the treated area being modeled. 

Many avian and mammalian species have been observed nesting, brood rearing and/or foraging 

in proposed crop areas. Others may be less directly affected if occupying adjacent areas 

receiving spray drift, but foraging activities in treated areas may follow after applications are 

completed. 
Page 69 of 125 

Differences feeding behavior from test scenarios

The acute studies have a fixed exposure period, not allowing for the differences in response of 

individuals to different durations of exposure. Further, for the acute oral study, tolfenpyrad is 

administered in a single dose which does not mimic a wild bird’s exposure through multiple 

feedings. Also, it does not account for absorption rate of the chemical into the animal. Because 

exposure occurs over several days, both the accumulated dose and elimination of the chemical 

from the body for the duration of the exposure will determine the exact exposure to wildlife. 

Variation in diet composition

The risk assessment and calculated RQs assume 100% of the diet is relegated to single food 

types foraged only from treated fields. The assumption of 100% diet from a single food type 

may be realistic for acute exposures, but diets are likely to be more variable over longer periods 

of time. Thus, chronic exposures should assume a variety of food types for certain species.

Exposure routes other than dietary

Only dietary exposure is included in the exposure assessment for risk quotient calculation. Other 

exposure routes are possible for animals in treated areas. These routes include ingestion of 

contaminated drinking water, dermal exposure (by direct or indirect means) and inhalation. 

Drinking water and inhalation exposure were assessed using two available screening tools. 

Because tolfenpyrad does not volatilize appreciably, inhalation does not appear to be a 

significant contributor to the overall exposure. The low solubility of the chemical and relatively 

high level of binding also suggest that runoff and puddles on the treated field are unlikely to 

contain the chemical at levels that may adversely impact avian or mammalian species, when 

drinking water exposure is considered alone. The Office of Pesticide Programs does not currently 

have modeling tools to assess dermal exposure to non-target birds and mammals. Because all 

potential routes of exposure are not considered aggregately, the risks of a toxic response to 

tolfenpyrad is underestimated in this risk assessment.

Choice of KOW Value for KABAM Modeling

A log KOW of 5.61 was used as input to the KABAM model for evaluating risks to piscivorous 

birds and mammals from the proposed uses of tolfenpyrad. This was the highest of the two 

available KOW values. Using this value, a maximum chronic RQ of 2.8 was identified for the 

fog/water shrew. No acute risks were identified for birds or mammals and no chronic risks were 

identified for birds. If the other available log KOW (4.3) was used, no acute or chronic risks 

would be identified to birds or mammals (maximum chronic mammalian RQ of 0.76).

6.3 Assumptions and Limitations Related to Exposure for Aquatic Species

The fate and transport database for tolfenpyrad was limited (for example, only one soil or one 

sediment system was used in each of the aerobic/anaerobic soil/aquatic metabolism studies), but 

sufficient to conduct aquatic modeling for exposure assessment of aquatic species. 

1. Since only one aerobic soil or anaerobic aquatic sediment system was included and all aerobic 

soil/anaerobic metabolism studies were selected from CA, the submitted studies may not 

represent all the proposed use areas. 
Page 70 of 125 

2. Tolfenpyrad was modeled in this assessment as relatively persistent (half-lives were timed 

with a factor of 3) because of limited number of metabolism studies are available (only one 

aerobic soil and one anaerobic aquatic sediment system were studied in each of the metabolism 

studies). If additional metabolism studies are available, EECs could be refined and would likely 

result in lower values.

3. Tolfenpyrad is a new chemical, no monitoring data were available to compare to the model 

estimates.

6.4 Assumptions and Limitations Related to Effects Assessment

Toxicity of degradates to terrestrial and aquatic invertebrate/plant taxa

Acute tests with freshwater fish show toxicity is moderate to low for the four degradates tested 

(LC50 values range from 768 ppb for the PT-CA to >10,000 ppb for the PAM degradate). These 

levels are well above expected EEC levels. However, no testing results for these degradates with 

other taxa has been provided. Thus, conclusions regarding toxicity of degradates to these taxa 

cannot be made with any certainty.

Age class and sensitivity of effects thresholds

It is generally recognized that test organism age may have a significant impact on the observed 

sensitivity to a toxicant. In general, testing of aquatic organisms is conducted with juvenile 

organisms. Testing of juveniles may overestimate toxicity of older age classes for pesticide 

active ingredients. 

Use of the most sensitive species tested

Although the screening risk assessment relies on a selected toxicity endpoint from the most 

sensitive species tested, it does not necessarily mean that the selected toxicity endpoint reflect 

sensitivity of the most sensitive species existing in a given environment. Levels of concern have 

been established at lower than a ratio of 1.0 in order to add some measure of conservatism, but it 

is not certain whether this accounts for the most sensitive organisms. If available, the Agency 

also considers toxicity data on non-standard test species.

Acknowledgements

The authors of this document would like to thank Justin Housenger and Dr. Michael Barrett for 

their valuable contributions to the assessment and secondary review of the initial review.
Page 71 of 125 

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48250427 Gallagher, S.P., Martin, K.H., and J.B. Beavers. 2008. Tolfenpyrad TGAI: A dietary LC50 study with 

the mallard. Unpublished study performed by Wildlife International, Ltd., Easton, Maryland. 

Laboratory Project Number: 397-107. Study sponsored by Nihon Nohyaku, Co. Ltd., Tokyo, Japan. 

Study completed January 14, 2008.

48250428 Temple, D.L., Martin, K.H., Beavers, J.B., and M. Jaber. 2008. Tolfenpyrad TGAI: A reproduction

48250429 study with the mallard. Unpublished study performed by Wildlife International, Ltd., Easton, 

Maryland. Laboratory Project Number: 397-112. Study sponsored by Nihon Nohyaku, Co. Ltd., 

Tokyo, Japan. Study completed May 14, 2008.

48250430 Temple, D.L., Martin, K.H., Beavers, J.B., and M. Jaber. 2008. Tolfenpyrad TGAI: A reproduction

48250431 study with the northern bobwhite. Unpublished study performed by Wildlife International, Ltd., 

Easton, Maryland. Laboratory Project Number: 397-111. Study sponsored by Nihon Nohyaku, Co. 

Ltd., Tokyo, Japan. Study completed May 14, 2008.

48250432 Schmitzer, S. 2005. Effects of Tolfenpyrad technical (acute contact and oral) on honey bees (Apis 

 mellifera L.) in the laboratory. Unpublished study performed by Institut fur Biologische Analytik und 

 Consulting IBACON GmbH, Rossdorf, Germany. Laboratory Project Number: 25741035. Study 

 sponsored by Nihon Nohyaku, Co. Ltd., Tokyo, Japan. Study completed September 5, 2005.

48250433 Porch, J.R. and H.O. Krueger. 2008. Tolfenpyrad 15% SC: A foliage residue toxicity study with the 

 honeybee. Unpublished study performed by Wildlife International, Ltd., Easton, Maryland. Laboratory 

 Project Number: Laboratory Project Number: 397-115. Study sponsored by Nihon Nohyaku, Co. Ltd., 

 Tokyo, Japan. Study completed on October 30, 2008.

48250434 Porch, J.R., Martin, K.H., and H.O. Krueger. 2008. Tolfenpyrad 15% SC: A toxicity test to determine 

the effects of the test substance on seedling emergence of ten species of plants. Unpublished study 

performed by Wildlife International, Ltd., Easton, Maryland. Laboratory project no.: 397-113. Study 

sponsored by Nihon Nohyaku Co. Ltd., Tokyo, Japan. Study completed June 27, 2008.
Page 76 of 125 

48250435 Porch, J.R., Martin, K.H., and H.O. Krueger. 2008. Tolfenpyrad 15% SC: A toxicity test to determine 

the effects of the test substance on vegetative vigor of ten species of plants. Unpublished study 

performed by Wildlife International, Ltd., Easton, Maryland. Laboratory project no.: 397-114. Study 

sponsored by Nihon Nohyaku Co. Ltd., Tokyo, Japan. Study completed July 1, 2008.

48250436 Minderhout, T., Kendall, T.Z., and H.O. Krueger. 2009. Tolfenpyrad TGAI: A 7-day static-renewal 

toxicity test with duckweed (Lemna gibba G3). Unpublished study performed by Wildlife 

International, Ltd., Easton, Maryland. Laboratory project no.: 397A-129A. Study sponsored by Nihon 

Nohyaku Co. Ltd., Tokyo, Japan. Study completed June 5, 2009.

48250437 Minderhout, T., Chafey, K.W., and H.O. Krueger. 2008. Tolfenpyrad TGAI: A 96-hour toxicity test 

with the freshwater alga (Pseudokirchneriella subcapitata). Unpublished study performed by Wildlife 

International, Ltd., Easton, Maryland. Laboratory project no.: 397A-123. Study sponsored by Nihon 

Nohyaku Co. Ltd., Tokyo, Japan. Study completed December 2, 2008.

48250438 Minderhout, T., Kendall, T.Z., and H.O. Krueger. 2009. Tolfenpyrad TGAI: A 96-hour toxicity test 

with the freshwater alga (Anabaena flos-aquae). Unpublished study performed by Wildlife 

International, Ltd., Easton, Maryland. Laboratory project no.: 397A-128. Study sponsored by Nihon 

Nohyaku Co. Ltd., Tokyo, Japan. Study completed June 5, 2009.

48250439 Minderhout, T., Kendall, T.Z., and H.O. Krueger. 2008. Tolfenpyrad TGAI: A 96-hour toxicity test 

with the freshwater diatom (Navicula pelliculosa). Unpublished study performed by Wildlife 

International, Ltd., Easton, Maryland. Laboratory project no.: 397A-130. Study sponsored by Nihon 

Nohyaku Co. Ltd., Tokyo, Japan. Study completed December 2, 2008.

48250440 Minderhout, T., Kendall, T.Z., and H.O. Krueger. 2009. Tolfenpyrad TGAI: A 96-hour toxicity test 

with the marine diatom (Skeletonema costatum). Unpublished study performed by Wildlife 

International, Ltd., Easton, Maryland. Laboratory project no.: 397A-131D. Study sponsored by Nihon 

Nohyaku Co. Ltd., Tokyo, Japan. Study completed June 15, 2009.

48250441 Oishi, N. 2001. Growth inhibition study of OMI-88 SC in a green alga (Selenastrum capricornutum). 

Unpublished study performed by Biosafety Research Center, Foods, Drugs and Pesticides (An-Pyo 

Center), Shizuoka, Japan. Laboratory project no.: 397A-123. Study sponsored by Mitsubishi Chemical 

Corporation, Agrochemicals Laboratory, Specialty Chemicals Research Center, Yokohama, Japan. 

Study completed June 27, 2001.

48660302 Yaginuma, S. (2009) Acute Toxicity Test of PT-CA with Carp (Cyprinus carpio): Final Report. Project 

Number: W/10032, LSRC/E09/127A, GC/11/09/0098. Unpublished study prepared by Nihon Nohyaku 

Co., Ltd. 47p.

48953801 Gallagher, S.; Kendall, T.; Brougher, D. et al. (2012) PT(A)-40H: A 96-Hour Static Acute Toxicity Test 

with the Rainbow Trout (Oncorhynchus mykiss); Final Report. Project Number: 397A/159, W/10039. 

Unpublished study prepared by Wildlife International Ltd. 40p.

48953802 Brougher, D.; Kendall, T.; Gallagher, S. et al. (2012) PCA: A 96-Hour Static Acute Toxicity Test with 

the Rainbow Trout (Oncorhynchus mykiss): Final Report. Project Number: W/10037, 397A/161. 

Unpublished study prepared by Wildlife International Ltd. 39p.

48953803 Brougher, D.; Kendall, T.; Krueger, H.; et al. (2012) (Inert Ingredient): A 96-Hour Static Acute Toxicity 

Test with the Rainbow Trout (Oncorhynchus mykiss): Final Report. Project Number: 397A/160, 

W/10036. Unpublished study prepared by Wildlife International Ltd. 39p.

48953804 Brougher, D.; Kendall, T.; Gallagher, S. et al. (2012) PT-CA: A 96-Hour Static Acute Toxicity Test with 

the Rainbow Trout (Oncorhynchus mykiss): Final Report. Project Number: W/10038, 397A/162. 

Unpublished study prepared by Wildlife International Ltd. 40p.
Page 77 of 125 

Appendix A. Summary of Minor Degradate Formation from Degradation of Tolfenpyrad 

and the chemical Structures 

Summary of minor degradate formation from degradation of Tolfenpyrad. 

STUDY 

TYPE

MINOR DEGRADATE and MAXIMUM CONCENTRATION SOURCE

MRID

PAM (% 

applied)

PT-CA (% 

applied)

OH-PAM

(% 

applied)

PCA (% 

applied)

PT-OH 

(% 

applied)

PT-CHO

(% 

applied)

PT(A)-

4OH (% 

applied)

OH-PTOH (% 

applied)

Batch 

Equilibrium

– – – – – – – –

Hydrolysis – – – –

– – – – 47447713

Aqueous 

Photolysis

0.3% at 69 

hours (dark 

pyrazole 

label)

4.0% at 307.5 

hours 

(irradiated 

pyrazole 

label)

2.4% at 216 

hours 

(irradiated 

tolyloxy 

label)

– – 6.2% at 212.1 

hours 

(irradiated 

pyrazole 

label)

– – – 47463701

Soil 

Photolysis

0.9% at 213-

310.3 hours 

(dark 

pyrazole 

label)

0.7% at 144.5 

hours 

(irradiated 

pyrazole 

label)

2.0% at 310.3 

hours (dark 

pyrazole 

label)

4.7% at 313.5 

hours (dark 

tolyloxy 

label)

3.5% at 310.3 

hours 

(irradiated 

pyrazole 

label)

– 1.3% at 310.3 

hours 

(irradiated 

pyrazole 

label)

0.2% at 213 

hours (dark 

pyrazole 

label)

1.3% at 145.5 

hours 

(irradiated 

tolyloxy 

label)

0.2% at 70.5, 

145.5-313.5 

hours (dark 

tolyloxy 

label)

6.6% at 310.3 

hours 

(irradiated 

pyrazole 

label)

1.3% at 44.6 

hours (dark 

pyrazole 

label)

2.0% at 47 

hours 

(irradiated 

tolyloxy 

label)

0.3% at 94 

hours (dark 

tolyloxy 

label)

– – 47447715

Aerobic Soil 

Metabolism

3.8% at 90 

days 

(pyrazole 

label)

– – – 0.3% at 1 day 

(tolyloxy 

label)

– 4.3% at 30 

days 

(pyrazole 

label)

– 47447716

48250406

Anaerobic 

Soil 

Metabolism

4.9% at 136 

days, total 

system 

(pyrazole 

label)

– –

4.6% at 135 

days, water 

(tolyloxy 

label)

– – –

0.2% at 135 

days, water 

(tolyloxy 

label)

48250407

Anaerobic 

Aquatic 

Metabolism

2.2% at 3 

days, total 

system 

(pyrazole 

label)

– –

0.4% at 241 

days, total 

system 

(pyrazole 

label)

– –

7.8% at 182 

days, total 

system 

(pyrazole 

label)

– 482504.9
Page 78 of 125 

Summary of minor degradate formation from degradation of Tolfenpyrad. 

STUDY 

TYPE

MINOR DEGRADATE and MAXIMUM CONCENTRATION SOURCE

MRID

PAM (% 

applied)

PT-CA (% 

applied)

OH-PAM

(% 

applied)

PCA (% 

applied)

PT-OH 

(% 

applied)

PT-CHO

(% 

applied)

PT(A)-

4OH (% 

applied)

OH-PTOH (% 

applied)

Aerobic 

Aquatic 

Metabolism – – – – – – –

0.1% at 30 

days, water

(tolyloxy 

label)

48250408

- -

1.3% at 60 

days – – – – - 48953811

Terrestrial 

Field 

Dissipation

–

Detected only 

in 0-15 cm 

soil depth

– – – – – – 48250410

Studies conducted with both pyrazole and tolyloxy radiolabels include: aqueous photolysis, soil photolysis, aerobic 

and anaerobic soil metabolism, aerobic and anaerobic aquatic metabolism and terrestrial field dissipation. Studies 

conducted with pyrazole radiolabel only include hydrolysis and adsorption-desorption. The non-guideline analytical 

methods study was not radiolabelled. 
Page 79 of 125 

Chemical Structures of Tolfenpyrad and its Degradates

Tolfenpyrad

IUPAC Name: 4-Chloro-3-ethyl-1-methyl-N-[4-(p-tolyloxy)benzyl]pyrazole-5-carboxamide.

CAS Name: 4-Chloro-3-ethyl-1-methyl-N-[[4-(4-methylphenoxy)phenyl]methyl]-1Hpyrazole-5-carboxamide.

CAS Number: 129558-76-5.

SMILES 

String:

C3(Cl)C(CC)=NN(C)C=3C(=O)NCC1C=CC(OC2=CC=C(C)C=C2)=CC=1 

(EPI Suite, v3.12 SMILES string from ISIS .MOL file).

Empirical formula: C21H22ClN3O2 Molecular formula: C21H22ClN3O2

[Pyrazole ring-3-

14C]Tolfenpyrad

[PYR14C]Tolfenpyrad

[Pyrazole-3-

14C]Tolfenpyrad

[Pyrazole14C]Tolfenpyrad

[Py14C]Tolfenpyrad

* = Location of the radiolabel.

[Tolyloxy ring14C]Tolfenpyrad

[TO14C]Tolfenpyrad

[To14C]Tolfenpyrad

N

N

H3C O

H N C

O

Cl

CH3

H3C

N

N

H3C O

H N C

O

Cl

CH3

H3C

*
Page 80 of 125 

[Tolyloxy14C]Tolfenpyrad

* = Location of the radiolabel.

PAM

IUPAC Name: 4-Chloro-3-ethyl-1-methyl-1H-pyrazole-5-carboxamide (ISIS/Draw with 

ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

PCA [Tolfenpyrad-PCA]

IUPAC Name: 4-Chloro-3-ethyl-1-methyl-1H-pyrazole-5-carboxylic acid (ISIS/Draw with 

ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

N

N

H3C O

H N C

O

Cl

CH3

H3C

*

N

H N C N

O

Cl

CH3

H3C

H
Page 81 of 125 

PT-CHO

IUPAC Name: 4-Chloro-3-ethyl-N-[4-(4-formylphenoxy)benzyl]-1-methyl-1H-pyrazole-5-

carboxamide (ISIS/Draw with ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

PT-OH

IUPAC Name: 4-Chloro-3-ethyl-N-{4-[4-(hydroxymethyl)phenoxy]benzyl}-1-methyl-1Hpyrazole-5-carboxamide (ISIS/Draw with ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

N

C N

O

Cl

CH3

H3C

HO

N

N

O

H N C

O

Cl

CH3

H3C

OHC
Page 82 of 125 

PT-CA [Tolfenpyrad-PT-CA]

IUPAC Name: 4-[4-({[(4-Chloro-3-ethyl-1-methyl-1H-pyrazol-5-

yl)carbonyl]amino}methyl)phenoxy]benzoic acid (ISIS/Draw with 

ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

PT(A)-4OH [PT(A)-4-OH]

IUPAC Name: 4-Chloro-3-ethyl-N-(4-hydroxybenzyl)-1-methyl-1H-pyrazole-5-

carboxamide (ISIS/Draw with ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

N

N

O

H N C

O

Cl

CH3

H3C

HO

N

N

O

H N C

O

Cl

CH3

H3C

HO

O
Page 83 of 125 

OH-PT-OH

IUPAC Name: 4-Chloro-5-[({4-[4-hydroxymethyl)phenoxy]benzyl}amino)carbonyl]-1-

methyl-1H-pyrazole-3-carboxylic acid (ISIS/Draw with ACD/Name addin).

CAS Name: Not reported.

CAS Number: Not reported.

Or

N

N

HO

H N C

O

Cl

CH3

H3C

N

N

O

H N C

O

Cl

CH3

HO

OH

O

N

N

O

H N C

28

O

Cl

CH3

HO

OH

CH3
Page 84 of 125 

OH-PAM

IUPAC Name: 4-Chloro-3-(1-hydroxyethyl)-1-methyl-1H-pyrazole-5-carboxamide 

(ISIS/Draw with ACD/Name add-in).

CAS Name: Not reported.

CAS Number: Not reported.

N

H N C N

O

Cl

CH3

H3C

H

OH
85

Appendix B. Proposed route of degradation of tolfenpyrad in aerobic soil system, chemical 

structure of tolfenpyrad and degradates and minor degradate formation
86

Appendix C Terrestrial Model Descriptions/Inputs /Outputs

EFED Terrestrial Model Descriptions

The T-REX model (Version 1.5.1) calculates the residues on avian and mammalian food items to 

estimate acute and chronic dietary exposure and risk. As a conservative approach, the modeled 

environmental exposure concentrations are the single-day maximum.

The TerrPlant model (version 1.2.2) provides screening level estimates of exposure to terrestrial 

plants from single pesticide applications. TerrPlant derives pesticide EECs in chemical drift and 

runoff. The model does not consider exposures to plants from multiple pesticide applications. 

RQs are developed for non-listed and listed species of monocots and dicots inhabiting dry and 

semi-aquatic areas which are adjacent to pesticide treatment sites. 

This assessment utilizes two screening tools to assess the potential for tolfenpyrad exposure to 

terrestrial animals via inhalation and drinking water exposure. The potential for inhalation risk to 

birds and mammals was assessed using the Screening Tool for Inhalation Risk (STIR, version 

1.0, November 2010). The STIR tool estimates spray droplet and vapor phase exposure using the 

physical properties of each chemical, application method and rate and then compares these 

exposure estimates to avian and mammalian toxicity data. The model estimates avian inhalation 

toxicity values from available mammalian data by applying an adjustment factor representing the 

difference in lung tissue thickness and surface area between birds and mammals to the 

relationship between mammalian-oral, mammalian-inhalation, and avian-oral toxicity values to 

account for differences in avian and mammalian inhalation toxicity. The Screening Imbibition 

Program (SIP, version 1.0, July 2010) was used to provide upper-bound drinking water exposure 

potential using tolfenpyrad’s solubility, the most sensitive acute and chronic avian toxicity 

endpoints and the most sensitive acute and chronic mammalian toxicity endpoints.

Additional information on the terrestrial exposure models and screening tools employed in this 

risk assessment can be found at http://www.epa.gov/oppefed1/models/terrestrial/.
87

Example of T-Rex Input /Output for Citrus application 0.27 Lb ai/Acre

Chemical Application Parameters:

Chemical Name: Tolfenpyrad

 Use Citrus

 Formulation Tolfenpyrad 15 SC

Application Rate 0.27 lbs a.i./acre

Half-life 35 days 

Application Interval 14 days

Maximum # Apps./Year 2

Length of Simulation 1 year

Variable application 

rates? no

Toxicity Endpoints

Avian

zebra finch LD50 (mg/kg-bw) 58.00

Bobwhite quail LC50 (mg/kg-diet) 1348.00

Mallard duck NOAEL(mg/kg-bw) 25.00

Mallard duck NOAEC (mg/kg-diet) 9.70

Mammals

LD50 (mg/kg-bw) 239.00

LC50 (mg/kg-diet) 0.00

NOAEL (mg/kg-bw) 0.86

NOAEC (mg/kg-diet) 15.00

TREX Outputs:

Dietary-based EECs (ppm) Kenaga

Values

Short Grass 113.91

Tall Grass 52.21

Broadleaf plants 64.07

Fruits/pods/seeds 7.12

Arthropods 44.61
88

Avian Intermediate Calculations:

Avian Body 

Ingestion 

(Fdry)

Ingestion 

(Fwet)

% body 

wgt FI

Class Weight (g) (g bw/day) (g/day) consumed (kg-diet/day)

Small 20 5 23 114 2.28E-02

Mid 100 13 65 65 6.49E-02

Large 1000 58 291 29 2.91E-01

20 5 5 25 5.06E-03

Granivores 100 13 14 14 1.44E-02

1000 58 65 6 6.46E-02

Avian Body Adjusted LD50

Weight (g) (mg/kg-bw)

20 62.62

100 79.72

1000 112.60

Avian Results:

Avian Dose-based EECs 

(mg/kg-bw)

Avian Classes and Body Weights (grams)

small mid large

20 100 1000

Short Grass 129.73 73.98 33.12

Tall Grass 59.46 33.91 15.18

Broadleaf plants 72.97 41.61 18.63

Fruits/pods 8.11 4.62 2.07

Arthropods 50.81 28.97 12.97

Seeds 1.80 1.03 0.46

Dose-based RQs 

(Dose-based 

EEC/adjusted LD50)

Avian Acute RQs

Size Class (grams)

20 100 1000

Short Grass 2.07 0.93 0.29

Tall Grass 0.95 0.43 0.13

Broadleaf plants 1.17 0.52 0.17

Fruits/pods 0.13 0.06 0.02

Arthropods 0.81 0.36 0.12

Seeds 0.03 0.01 0.00

Dietary-based RQs 

(Dietary-based 

EEC/LC50 or NOAEC)

RQs

Acute Chronic

Short Grass 0.08 11.74

Tall Grass 0.04 5.38

Broadleaf plants 0.05 6.61

Fruits/pods/seeds 0.01 0.73

Arthropods 0.03 4.60
89

Mammalian Intermediate Calculations:

Mammalian Body 

Ingestion 

(Fdry) Ingestion (Fwet) % body wgt FI

Class Weight (g bwt/day) (g/day) consumed (kg-diet/day)

15 3 14 95 1.43E-02

Herbivores/ 35 5 23 66 2.31E-02

insectivores 1000 31 153 15 1.53E-01

15 3 3 21 3.18E-03

Grainvores 35 5 5 15 5.13E-03

1000 31 34 3 3.40E-02

Mammalian Body Adjusted Adjusted

Class Weight LD50 NOAEL

15 525.28 1.89

Herbivores/ 35 425.01 1.53

insectivores 1000 183.83 0.66

15 525.28 1.89

Granivores 35 425.01 1.53

1000 183.83 0.66

Mammalian Results:

Dose-Based 

EECs 

(mg/kg-bw)

Mammalian Classes and Body weight

(grams)

15 35 1000

Short Grass 108.60 75.06 17.40

Tall Grass 49.78 34.40 7.98

Broadleaf plants 61.09 42.22 9.79

Fruits/pods 6.79 4.69 1.09

Arthropods 42.54 29.40 6.82

Seeds 1.51 1.04 0.24

Dose-based RQs 

(Dose-based 

EEC/LD50 or 

NOAEL)

Small mammal Medium mammal Large mammal

15 grams 35 grams 1000 grams

Acute Chronic Acute Chronic Acute Chronic

Short Grass 0.21 57.46 0.18 49.08 0.09 26.31

Tall Grass 0.09 26.34 0.08 22.50 0.04 12.06

Broadleaf plants 0.12 32.32 0.10 27.61 0.05 14.80

Fruits/pods 0.01 3.59 0.01 3.07 0.01 1.64

Arthropods 0.08 22.50 0.07 19.22 0.04 10.30

Seeds 0.00 0.80 0.00 0.68 0.00 0.37
90

Dietary-based RQs (Dietarybased EEC/LC50 or NOAEC)

Mammal RQs

Acute Chronic

Short Grass #DIV/0! 7.59

Tall Grass #DIV/0! 3.48

Broadleaf plants #DIV/0! 4.27

Fruits/pods/seeds #DIV/0! 0.47

Arthropods #DIV/0! 2.97

TerrPlant Output

TerrPlant v. 1.2.2 –tolfenpyrad maximum aerial and ground use scenarios

Aerial Application on Citrus

Table 1. Chemical Identity.

Chemical Name Tolfenpyrad

PC code 90111

Use Peaches

Application Method Aerial

Application Form Spray 

Solubility in Water (ppm) 0.087

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 0.27 lb ai/A

Incorporation I 1 none

Runoff Fraction R 0.01 none

Drift Fraction D 0.05 none

Table 3. EECs for Tolfenpyrad. Units in lb ai/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.0027

Runoff to semi-aquatic areas (A/I)*R*10 0.027

Spray drift A*D 0.014

Total for dry areas ((A/I)*R)+(A*D) 0.0162

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.041

Table 4. Plant survival and growth data used for RQ derivation. Units are in lb ai/A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 0.265 0.265 0.265 0.265

Dicot 0.265 0.265 0.265 0.265
91

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Tolfenpyrad through runoff 

and/or spray drift.*

Plant Type

Listed 

Status Dry Semi-Aquatic Spray Drift

Monocot non-listed <0.1 0.16 <0.1

Monocot listed <0.1 0.16 <0.1

Dicot non-listed <0.1 0.16 <0.1

Dicot listed <0.1 0.16 <0.1

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.

Ground application on Grapes

Table 1. Chemical Identity.

Chemical Name Tolfenpyrad

PC code 90111

Use Grapes

Application Method Ground

Application Form Spray 

Solubility in Water (ppm) 0.087

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 0.27 lb ai/A

Incorporation I 1 none

Runoff Fraction R 0.01 none

Drift Fraction D 0.01 none

Table 3. EECs for Tolfenpyrad. Units in lb ai/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.0027

Runoff to semi-aquatic areas (A/I)*R*10 0.027

Spray drift A*D 0.0027

Total for dry areas ((A/I)*R)+(A*D) 0.0054

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.0297

Table 4. Plant survival and growth data used for RQ derivation. Units are in lb ai/A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 0.265 0.265 0.265 0.265

Dicot 0.265 0.265 0.265 0.265
92

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Tolfenpyrad through 

runoff and/or spray drift.*

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed <0.1 0.11 <0.1

Monocot listed <0.1 0.11 <0.1

Dicot non-listed <0.1 0.11 <0.1

Dicot listed <0.1 0.11 <0.1

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.
93

Screening Tool for Inhalation Risk (STIR), version 1.0 Results:

Input

Application and Chemical Information

Enter Chemical Name Tofenpyrad

Enter Chemical Use Citrus

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

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 385.7

Enter Chemical Vapor Pressure (mmHg) 3.00E-07

Enter Application Rate (lb a.i./acre) 0.27

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 58

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 0.178

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 239

Enter Lowest Rat Inhalation LC50 (mg/L) 1.5

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at 

Saturation (mg/m3)

6.23E-03

Maximum 1-hour Vapor Inhalation Dose 

(mg/kg)

7.83E-04

Adjusted Inhalation LD50 2.03E+00

Ratio of Vapor Dose to Adjusted Inhalation 

LD50

3.86E-04 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation 

Dose (mg/kg)

2.85E-02

Ratio of Droplet Inhalation Dose to Adjusted 

Inhalation LD50

1.41E-02 Exposure not Likely Significant

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at 

Saturation (mg/m3)

6.23E-03

Maximum 1-hour Vapor Inhalation Dose 

(mg/kg)

9.84E-04

Adjusted Inhalation LD50 8.93E+01

Ratio of Vapor Dose to Adjusted Inhalation 

LD50

1.10E-05 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation 

Dose (mg/kg)

3.59E-02

Ratio of Droplet Inhalation Dose to Adjusted 

Inhalation LD50

4.02E-04 Exposure not Likely Significant
94
95

Appendix D

Risk Quotient Methods and Level-of-Concern Definitions 

The Risk Quotient Method is the means by which the Environmental Fate and Effects Division 

(EFED) integrates the results of exposure and ecotoxicity data. In this method, both acute and 

chronic risk quotients (RQs) are calculated by dividing exposure estimates by the most sensitive 

ecotoxicity values derived from the studies. Calculated RQs are then compared to levels-ofconcern (LOCs). The LOCs are the criteria used by Office of Pesticide Programs to indicate 

potential risk to non-target organisms and the need to consider regulatory action. EFED has 

defined LOCs for acute risk, potential restricted use, and for listed species. Risk presumptions, 

along with the corresponding RQs and LOCs are summarized in the table below.

Table D-1. Levels of Concern for Assessed Taxa

Risk Presumption RQ LOC

Birds

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 50 

mg/kg)

0.2

Acute Listed Species EEC/LC50 or LD50/sqft or LD50/day 0.1

Chronic Risk EEC/NOAEC 1

Mammals

Acute Risk EEC/LC50 or LD50/sqft or LD50/day 0.5

Acute Restricted Use EEC/LC50 or LD50/sqft or LD50/day (or LD50 < 50 

mg/kg)

0.2

Acute Listed Species EEC/LC50 or LD50/sqft or LD50/day 0.1

Chronic Risk EEC/NOAEC 1

Aquatic Animals

Acute Risk EEC/LC50 or EC50 0.5

Acute Restricted Use EEC/LC50 or EC50 0.1

Acute Listed Species EEC/LC50 or EC50 0.05

Chronic Risk EEC/NOAEC 1

Terrestrial and Semi-Aquatic Plants 

Acute Risk EEC/EC25 1

Acute Listed Species EEC/EC05 or NOAEC 1

Aquatic Plants

Acute Risk EEC/EC50 1

Acute Listed Species EEC/EC05 or NOAEC 1
96

Appendix E. KABAM Inputs and Outputs for TX Cotton Scenario

The KABAM model (KOW (based) Aquatic BioAccumulation Model) version 1.0 was used as the 

primary tool for evaluating the potential exposure and risk to birds and mammals that feed on 

aquatic organisms. KABAM is used to estimate potential bioaccumulation of hydrophobic 

organic pesticides in freshwater aquatic ecosystems and risks to mammals and birds consuming 

aquatic organisms which have bioaccumulated these pesticides. The bioaccumulation portion of 

KABAM is based upon work by Arnot and Gobas (2004) who parameterized a bioaccumulation 

model based on PCBs and some pesticides, such as lindane and DDT, in freshwater aquatic 

ecosystems. KABAM relies on a chemical's octanol-water partition coefficient (KOW) to estimate 

uptake and elimination constants through respiration and diet of organisms in different trophic 

levels. Pesticide tissue residues are calculated for organisms at different trophic levels of an 

aquatic food web. Although the default parameterization of KABAM assumes no chemical 

metabolism by biota, the metabolism rate constant can be adjusted to reflect appropriate 

information on chemical metabolism. The model then uses pesticide tissue concentrations in 

aquatic animals to estimate dose- and dietary-based exposures and associated risks to mammals 

and birds consuming aquatic organisms. The KABAM model and associated documentation can 

be found at 

http://www.epa.gov/oppefed1/models/water/kabam/kabam_user_guide_appendix_d.html. 

Table E-1. Chemical characteristics of Tolfenpyrad.

Characteristic Value Comments/Guidance

Pesticide Name Tolfenpyrad Required input

Log KOW 5.61

Required input 

Enter value from acceptable or supplemental study submitted 

by registrant or available in scientific literature.

KOW 407380 No input necessary. This value is calculated automatically 

from the Log KOW value entered above.

KOC (L/kg 

OC) 29380

Required input

Input value used in PRZM/EXAMS to derive EECs. Follow 

input parameter guidance for deriving this parameter value 

(USEPA 2002).

Time to steady 

state (TS; days) 113 No input necessary. This value is calculated automatically from the Log KOW value entered above.

Pore water EEC 

(μg/L) 0.31

Required input 

Enter value generated by PRZM/EXAMS benthic file. 

PRZM/EXAMS EEC represents the freely dissolved 

concentration of the pesticide in the pore water of the 

sediment. The appropriate averaging period of the EEC is 

dependent on the specific pesticide being modeled and is 

based on the time it takes for the chemical to reach steady 

state. Select the EEC generated by PRZM/EXAMS which has 

an averaging period closest to the time to steady state 

calculated above. In cases where the time to steady state 

exceeds 365 days, the user should select the EEC 

representing the average of yearly averages. The peak EEC 

should not be used. 

Water Column 

EEC (μg/L) 2.68

Required input 

Enter value generated by PRZM/EXAMS water column file. 

PRZM/EXAMS EEC represents the freely dissolved 
97

Table E-1. Chemical characteristics of Tolfenpyrad.

Characteristic Value Comments/Guidance

concentration of the pesticide in the water column. The 

appropriate averaging period of the EEC is dependent on the 

specific pesticide being modeled and is based on the time it 

takes for the chemical to reach steady state. The averaging 

period used for the water column EEC should be the same as 

the one selected for the pore water EEC (discussed above). 

Table E-2. Input parameters for rate constants. "calculated" indicates that model will calculate 

rate constant. 

Trophic level

k1 

(L/kg*d)

k2 

(d-1)

kD 

(kg-food/kgorg/d)kE 

(d-1)

kM* 

(d-1)

phytoplankton calculated calculated 0* 0* 0

zooplankton calculated calculated calculated calculated 0

benthic invertebrates calculated calculated calculated calculated 0

filter feeders calculated calculated calculated calculated 0

small fish 651.5 0.214 calculated 0 0

medium fish 651.5 0.214 calculated 0 0

large fish 651.5 0.214 calculated 0 0

* Default value is 0. 

k1 and k2 represent the uptake and elimination constants respectively, through 

respiration.

kD and kE represent the uptake and elimination constants, respectively, through diet.

kM represents the metabolism rate constant. 

Table E-3. Mammalian and avian toxicity data for Tolfenpyrad. These are required inputs.

Animal

Measure of 

effect (units) Value Species

If selected 

species is 

"other," enter 

body weight 

(in kg) here.

Avian LD50 (mg/kg-bw) 58 other 0.012

LC50 (mg/kg-diet) 1348 Northern bobwhite quail

NOAEC (mg/kgdiet) 9.7 mallard duck

Mineau Scaling 

Factor 1.15

Default value for all species is 

1.15 (for chemical specific 

values, see Mineau et al. 

1996).

Mammalian LD50 (mg/kg-bw) 239 laboratory rat

LC50 (mg/kg-diet) N/A laboratory rat

Chronic Endpoint 0.86 laboratory rat

units of chronic 

endpoint* mg/kg-bw

*ppm = mg/kg-diet
98

Table E-4. Abiotic characteristics of the model aquatic ecosystem.

Characteristic Value Guidance*

Concentration of 

Particulate Organic 

Carbon 

(XPOC; kg OC/ L)

0.00E+00

When using EECs generated by PRZM/EXAMS, use a value of “0” for 

Concentration of both POC and DOC. 

Dissolved Organic 

Carbon 

(XDOC; kg OC/L)

0.00E+00

Concentration of 

Dissolved Oxygen 

(COX; mg O2/L)

5.0 Default value is 5.0 mg O2/L when using EECs generated by 

PRZM/EXAMS.

Water Temperature 

(T; oC) 15

Value is defined by the average water temperature of the EXAMS pond 

when using EECs generated by PRZM/EXAMS. Model user should 

consult output file of EXAMS to define this value.

Concentration of 

Suspended Solids 

(CSS; kg/L)

3.00E-05 Default value is 3.00x10-5

kg/L when using EECs generated by 

PRZM/EXAMS.

Sediment Organic 

Carbon 

(OC; %)

4.0% Default value is 4.0% when using EECs generated by PRZM/EXAMS.

*When using pesticide concentrations from monitoring data or mesocosm studies, consult Appendix B of 

the User’s Guide for specific guidance on selecting values for these parameters.

Table E-5. Characteristics of aquatic biota of the model ecosystem.

Trophic Level Wet Weight (kg) % lipids % NLOM % Water

Do 

organisms in 

trophic level 

respire some 

pore water?

sediment* N/A 0.0% 4.0% 96.0% N/A

phytoplankton N/A 2.0% 8.0% 90.0% no

zooplankton 1.0E-07 3.0% 12.0% 85.0% no

benthic invertebrates 1.0E-04 3.0% 21.0% 76.0% yes

filter feeders 1.0E-03 2.0% 13.0% 85.0% yes

small fish 1.0E-02 4.0% 23.0% 73.0% yes

medium fish 1.0E-01 4.0% 23.0% 73.0% yes

large fish 1.0E+00 4.0% 23.0% 73.0% no

*Note that sediment is not a trophic level. It is included in this table because it is consumed by aquatic 

organisms of the KABAM foodweb.

N/A = not applicable

Table E-6. Diets of aquatic biota of the model ecosystem.

Diet for: 

Trophic level in 

diet Zoo plankton

Benthic 

Invertebrates

Filter 

Feeder Small Fish

Medium 

Fish Large Fish

sediment* 0.0% 34.0% 34.0% 0.0% 0.0% 0.0%

phytoplankton 100.0% 33.0% 33.0% 0.0% 0.0% 0.0%

zooplankton 33.0% 33.0% 50.0% 0.0% 0.0%

benthic invertebrates 0.0% 50.0% 50.0% 0.0%
99

Table E-6. Diets of aquatic biota of the model ecosystem.

Diet for: 

Trophic level in 

diet Zoo plankton

Benthic 

Invertebrates

Filter 

Feeder Small Fish

Medium 

Fish Large Fish

filter feeders 0.0% 0.0% 0.0%

small fish 50.0% 0.0%

medium fish 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

*Note that sediment is not a trophic level. It is included in this table because it is consumed by aquatic 

organisms of the KABAM foodweb.

Table E-7. Identification of mammals and birds feeding on 

aquatic biota of the model ecosystem.

Mammal/Bird # Name

Body weight 

(kg)

Mammal 1 fog/water shrew 0.018

Mammal 2 rice rat/star-nosed mole 0.085

Mammal 3 small mink 0.45

Mammal 4 large mink 1.8

Mammal 5 small river otter 5

Mammal 6 large river otter 15

Bird 1 sandpipers 0.02

Bird 2 cranes 6.7

Bird 3 rails 0.07

Bird 4 herons 2.9

Bird 5 small osprey 1.25

Bird 6 white pelican 7.5

Table E-8. Diets of mammals feeding on aquatic biota of the model ecosystem.

Trophic level in 

diet

Diet for: 

fog/water 

shrew

rice 

rat/starnosed 

mole

small 

mink

large 

mink

small 

river otter

large river 

otter

phytoplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

zooplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

benthic 

invertebrates 100.0% 34.0% 0.0% 0.0% 0.0% 0.0%

filter feeders 0.0% 33.0% 0.0% 0.0% 0.0% 0.0%

small fish 0.0% 33.0% 0.0% 0.0% 0.0% 0.0%

medium fish 0.0% 0.0% 100.0% 100.0% 100.0% 0.0%

large fish 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%
100

Table E-9. Diets of birds feeding on aquatic biota of the model ecosystem.

Diet for: 

Trophic level in 

diet sandpipers cranes rails herons

small 

osprey

white 

pelican

phytoplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

zooplankton 0.0% 0.0% 0.0% 0.0% 0.0% 0.0%

benthic 

invertebrates 33.0% 33.0% 50.0% 50.0% 0.0% 0.0%

filter feeders 33.0% 33.0% 0.0% 0.0% 0.0% 0.0%

small fish 34.0% 0.0% 50.0% 0.0% 0.0% 0.0%

medium fish 0.0% 34.0% 0.0% 50.0% 100.0% 0.0%

large fish 0.0% 0.0% 0.0% 0.0% 0.0% 100.0%

Total 100.0% 100.0% 100.0% 100.0% 100.0% 100.0%

Table E-10. Estimated concentrations of Tolfenpyrad (TX Cotton) in ecosystem 

components.

Ecosystem Component

Total 

concentration 

(μg/kg-ww)

Lipid 

normalized 

concentration 

(μg/kg-lipid)

Contribution

due to diet 

(μg/kg-ww)

Contribution 

due to 

respiration 

(μg/kg-ww)

Water (total)* 0.47 N/A N/A N/A

Water (freely dissolved)* 0.47 N/A N/A N/A

Sediment (pore water)* 0.31 N/A N/A N/A

Sediment (in solid)** 364 N/A N/A N/A

Phytoplankton 8,036 401795 N/A 8,035.90

Zooplankton 7,146 238190 735.24 6,410.46

Benthic Invertebrates 8,559 285299 1,958.67 6,600.29

Filter Feeders 5,610 280498 1,263.39 4,346.58

Small Fish 3,254 81354 1,855.85 1,398.30

Medium Fish 2,392 59793 990.41 1,401.32

Large Fish 1,712 42796 284.30 1,427.53

* Units: μg/L; **Units: μg/kg-dw

Table E-11. Total BCFand BAF values of Tolfenpyrad (TX 

Cotton) in aquatic trophic levels.

Trophic Level

Total BCF 

(μg/kgww)/(μg/L)

Total BAF 

(μg/kgww)/(μg/L)

Phytoplankton 19555 17098

Zooplankton 13933 15204

Benthic Invertebrates 14957 18211

Filter Feeders 9832 11936

Small Fish 2993 6924

Medium Fish 2993 5089

Large Fish 3044 3642
101

Table E-12. Lipid-normalized BCF, BAF, BMF and BSAF values of Tolfenpyrad (TX 

Cotton) in aquatic trophic levels.

Trophic Level

BCF 

(μg/kglipid)/(μg/L)

BAF 

(μg/kglipid)/(μg/L)

BMF 

(μg/kglipid)/(μg/kglipid)

BSAF 

(μg/kglipid)/(μg/kgOC)

Phytoplankton 977758 854883 N/A 44

Zooplankton 464442 506787 0.59 26

Benthic Invertebrates 498580 607018 1.35 31

Filter Feeders 491589 596805 1.33 31

Small Fish 74814 173093 0.31 9

Medium Fish 74814 127220 0.33 7

Large Fish 76110 91055 0.72 5

Table E-13. Calculation of EECs for mammals and birds consuming fish contaminated by 

Tolfenpyrad (TX Cotton).

Wildlife Species

Biological Parameters

EECs (pesticide 

intake)

Body

Weight

(kg)

Dry Food 

Ingestion 

Rate (kgdry food/kgbw/day)

Wet Food 

Ingestion 

Rate (kgwet 

food/kgbw/day)

Drinking 

Water

Intake

(L/d)

Dose 

Based 

(mg/kgbw/d)

Dietary 

Based 

(ppm)

Mammalian

fog/water shrew 0.02 0.140 0.585 0.003 5.009 8.56

rice rat/starnosed mole 0.1 0.107 0.484 0.011 2.823 5.84

small mink 0.5 0.079 0.293 0.048 0.702 2.39

large mink 1.8 0.062 0.229 0.168 0.548 2.39

small river otter 5.0 0.052 0.191 0.421 0.457 2.39

large river otter 15.0 0.042 0.157 1.133 0.269 1.71

Avian

sandpipers 0.0 0.228 1.034 0.004 5.9779 5.78

cranes 6.7 0.030 0.136 0.211 0.7460 5.49

rails 0.1 0.147 0.577 0.010 3.4103 5.91

herons 2.9 0.040 0.157 0.120 0.8618 5.48

small osprey 1.3 0.054 0.199 0.069 0.4769 2.39

white pelican 7.5 0.029 0.107 0.228 0.1827 1.71

Table E-14. Calculation of toxicity values for mammals and birds 

consuming fish contaminated by Tolfenpyrad (TX Cotton).

Wildlife Species

Toxicity Values

Acute Chronic

Dose 

Based 

(mg/kgbw)

Dietary 

Based 

(mg/kg-diet)

Dose Based 

(mg/kg-bw)

Dietary 

Based 

(mg/kgdiet)

Mammalian

fog/water shrew 501.9 N/A 1.81 17.2

rice rat/starnosed mole 340.5 N/A 1.23 17.2
102

Table E-14. Calculation of toxicity values for mammals and birds 

consuming fish contaminated by Tolfenpyrad (TX Cotton).

Wildlife Species

Toxicity Values

Acute Chronic

Dose 

Based 

(mg/kgbw)

Dietary 

Based 

(mg/kg-diet)

Dose Based 

(mg/kg-bw)

Dietary 

Based 

(mg/kgdiet)

small mink 224.4 N/A 0.81 17.2

large mink 158.7 N/A 0.57 17.2

small river otter 122.9 N/A 0.44 17.2

large river otter 93.4 N/A 0.34 17.2

Avian

sandpipers 62.7 1348.00 N/A 9.7

cranes 149.9 1348.00 N/A 9.7

rails 75.6 1348.00 N/A 9.7

herons 132.2 1348.00 N/A 9.7

small osprey 116.5 1348.00 N/A 9.7

white pelican 152.5 1348.00 N/A 9.7

Table E-15. Calculation of RQ values for mammals and birds 

consuming fish contaminated by Tolfenpyrad (TX Cotton).

Wildlife Species

Acute Chronic

Dose 

Based

Dietary 

Based

Dose Based Dietary 

Based

Mammalian

fog/water shrew 0.010 N/A 2.77 0.50

rice rat/starnosed mole 0.008 N/A 2.30 0.34

small mink 0.003 N/A 0.87 0.14

large mink 0.003 N/A 0.96 0.14

small river otter 0.004 N/A 1.03 0.14

large river otter 0.003 N/A 0.80 0.10

Avian

sandpipers 0.095 0.004 N/A 0.60

cranes 0.005 0.004 N/A 0.57

rails 0.045 0.004 N/A 0.61

herons 0.007 0.004 N/A 0.56

small osprey 0.004 0.002 N/A 0.25

white pelican 0.001 0.001 N/A 0.18
103

Appendix F

Health Effects Division mammalian toxicity profile

Table F-1 Acute Toxicity Profile -Tolfenpyrad 

Guideline 

No.

Study Type MRID(s) Results Toxicity 

Category

870.1100 Acute Oral -Rat 47457501 LD50 Males => 386 mg/kg bw 

LD50 Females =>150 mg/kg bw

LD50 Combined =>239 mg/kg bw

II

870.1200 Acute Dermal-Rat 47457503 LD50 Males > 2000 mg/kg bw 

LD50 Females > 3000 mg/kg bw

LD50 Combined > 2500 mg/kg bw

III

870.1300 Acute InhalationRat

47447734 LC50 Males >2.21 mg/L

LC50 Females >1.50 mg/L 

LC50 Combined >1.82 mg/L

III

870.2400 Acute Eye 

Irritation-Rabbit

47457505 Mildly irritating III

870.2500 Acute Dermal 

Irritation-Rabbit

47457507 Slightly irritating IV

870.2600 Skin 

SensitizationGuinea Pig

47447740 Not Sensitizing -

Table F-2 Subchronic, Chronic and Other Toxicity Profile for Tolfenpyrad

Type of 

Study/Gui

de line

Study Title MRID Results

870.3100 90-Day Oral 

Toxicity, Rat w/4 

week recovery 

47447743 Levels tested: 0, 15, 80, 160 ppm or 0/0, 0.9/1, 4.8/5.2, 9.3/9.3 

mg/kg/day in males/females

NOAEL (M/F) =15 ppm or 0.9/1 mg/kg/day

LOAEL (M/F) = 80 ppm or 4.8/5.2 mg/kg/day, based on 

decreased body weight (5-9%), body weight gain (8-13%), and 

food consumption in both sexes; increased relative liver and 

kidney weight, hepatocellular hypertrophy and kidney 

hypertrophy, hyaline droplets in the kidney, brown color change 

in the liver.; brown color change in the harderian gland along 

with hypersecretion. 

Additionally at 160 ppm, decreased body weight (8-26%), body 

weight gain (35-41%) and food consumption; small sex organs 

(seminal vesicle, ovary, uterus, and vagina; ovarian and uterine 

atrophy and decreased ovarian weight.

870.3100 90-Day Oral 

Toxicity, Mouse

47463702 

and 

47447801

Levels tested: 0, 15, 100, 300 pm or 0/0, 2.4/3.0, 15.9/20.2, 

46.2/57.9 mg/kg/day in males/females

NOAEL (M/F)-300 ppm or 46.2/57.9 mg/kg/day 

LOAEL (M/F)-not determined in main study; 600 ppm (104/126 
104

Table F-2 Subchronic, Chronic and Other Toxicity Profile for Tolfenpyrad

Type of 

Study/Gui

de line

Study Title MRID Results

mg/kg/day) based on decreased body weights, body weight gains, 

clinical signs (rough coats, hunched posture, ataxia, 

hypoactivity), and moribundity/mortality seen in 28 day oral 

study.

Note: Decreased Body weight gain (42%) was observed at 300 

ppm in the range-finding study; however, 600 ppm (the HDT) 

was selected as the LOAEL for the 90 day mouse study since no 

effects on body weight gain were seen in this study at 300 ppm. 

870.3150 4-week Oral 

Toxicity, Dog 

(capsule)

13-week Oral 

Toxicity, Dog 

(capsule)

47447805

47447803

Levels tested: 0, 1, 5, 10 mg/kg/day

NOAEL (M/F) = 5 mg/kg/day

LOAEL (M/F) = 10 mg/kg/day, based on abnormal feces and 

liver and kidney histopathology.

Levels tested: 0, 1, 5, 10 mg/kg/day

NOAEL (M/F) = 10 mg/kg/day

LOAEL (M/F) = Not determined

870.3150 13-week Oral 

Toxicity, Dog 

(capsule)

47447804 Levels tested: 0, 10, 30, 100 mg/kg/day

NOAEL (M/F) = 10 mg/kg/day

LOAEL (M/F) = 30 mg/kg/day, based on mortality (1/4 males); 

clinical signs (no defecation/watery feces, emaciation, decrease in 

spontaneous movement, and staggering gait); decreased body 

weights, body weight gains, and food consumption; and effects 

on the liver (increased cytoplasmic eosinophilia and centrilobular 

vacuolation in the hepatocytes) and in males, testes (atrophy) and 

kidney (vacuolization of tubular epithelium).

870.3200 21-Day Dermal 47447806 Levels tested: 0, 10, 50, 200 mg/kg/day

NOAEL (M/F) = 200 mg/kg/day

LOAEL (M/F) = not determined

At ≥ 50 mg/kg/day, decreased body weight gain and food 

consumption observed.

870.3250 90-Day Dermal No study Available: Waiver request submitted

870.3465 4-Week Inhalation 

Toxicity, Rat

47447728

and 

48250484 

(rangefinding)

Levels tested: 0, 0.50, 2.0, 10 mg/m3or 0, 0.0005, 0.002, and 0.01 

mg/L

NOAEL = 10 mg/m3 (EPA calculated 2.6 mg/kg/day)

LOAEL = not determined

Mortality observed at 26 mg/m3(EPA calculated 6.8 mg/kg/day)

in range-finding study. No mortality seen at the next lowest dose 

of 10.9 mg/m3

870.3700a Developmental 

Toxicity, Rat 

(Gavage)

47447809 Levels tested: 0, 1, 3, 4.5 mg/kg/day; GD 6-15)

Maternal NOAEL =1mg/kg/day

Maternal LOAEL = 3 mg/kg/day, based on decreased body 

weight gains and food consumption

Developmental NOAEL = 3 mg/kg/day

Developmental LOAEL = 4.5 mg/kg/day, based on increased 

incidences of 14th ribs, decreased fetal body weights, and 

decreased number of ossified metacarpals.

870.3700b Developmental 

Toxicity, Rabbit 

(Gavage)

47447811 Levels tested: 0, 1, 3, 6 mg/kg/day GD 6-18

Maternal NOAEL = 6 mg/kg/day

Maternal LOAEL = 9 mg/kg/day. The maternal LOAEL was not 

established in the current study but was 9 mg/kg/day in the 
105

Table F-2 Subchronic, Chronic and Other Toxicity Profile for Tolfenpyrad

Type of 

Study/Gui

de line

Study Title MRID Results

preliminary study (MRID 47447810) based on a single mortality, 

emaciation, and on decreased body weights, body weight gains, 

and food consumption

Developmental NOAEL = 6 mg/kg/day

Developmental LOAEL = 9 mg/kg/day. The developmental 

LOAEL was not established in the current study but was 9 

mg/kg/day in the preliminary study based on increased early 

resorption and incidences of supernumerary coronary orifices, 

fusion of the ossification centers of the caudal vertebral bodies, 

13th ribs, and delayed ossification of the manus

870.3800 2 Generation 

Reproduction, Rat 

(feeding)

47447817 Levels tested: 0, 0.75, 1.5, or 3.0 mg/kg/day. 

Parental NOAEL 1.5 mg/kg/day

Parental LOAEL = 3.0 mg/kg/day, based on decreased body 

weight and body weight gains, decreased motor activity, reddish 

tears, and prone position prior to death in two dams. 

Reproductive NOAEL 1.5 mg/kg/day

Reproductive LOAEL=3.0 mg/kg/day, based on decreased 

gestation index, increased gestation duration, abnormal 

parturition, and total litter loss Offspring NOAEL = 1.5 

mg/kg/day

Offspring LOAEL = 3.0 mg/kg/day, based on decreased pup 

viability and body weights, and delays in attainment of 

developmental landmarks (eye opening, pinna folding, surface 

righting reflex)

870.3800 1 Generation 

Reproduction, Rat 

(feeding)

47447816 Levels tested: 0, 15, 50, 100 ppm or 0/0, 0.86/0.92, 2.7/2.9, 

4.8/4.4 mg/kg/day. 

Parental NOAEL 15 ppm or 0.86/0.92 mg/kg/day

Parental LOAEL = 50 ppm or 2.7/2.9 mg/kg/day, based on 

decreased body weight gains and food consumption during premating, and on decreased body weights during gestation and 

lactation in the females. 

Reproductive NOAEL 50 ppm

Reproductive LOAEL= 100 ppm or 4.8/4.4, based on increased 

gestation duration

Offspring NOAEL = 15 ppm

Offspring LOAEL = 50 ppm, based on decreased body weights 

and body weight gains in both sexes.

870.4100 Chronic Toxicity-1 

Year, Dog 

(feeding)

47442818 Levels tested: 0, 1, 5, 10 (reduced from 20) mg/kg/day 

NOAEL (M/F) 5 mg/kg/day

LOAEL (M/F) 10 mg/kg/day, based on mortality, vomiting, 

decreased body weights, body weight gains, food consumption,, 

increased serum alanine aminotransferase in the males, and 

microscopic liver findings in males and females

870.4200b Chronic/Oncogenic

ity, 2- Year, Rat 

(feeding)

47463704 Levels tested: 0, 15, 40, 80 ppm or 0/0, 0.6/0.7, 1.5/1.9, and 

3.1/3.8 mg/kg/day in males/females

NOAEL (M/F) 15 ppm or 0.6/0.7 mg/kg/day

LOAEL (M/F) 40 ppm or 1.5/1.9 mg/kg/day, based on decreased 

body weight, body weight gain, and food consumption of 

females, gross changes in the Harderian glands of males, and 

histopathological changes in the liver, kidney and mesenteric 

lymph nodes of females and the kidney of males.
106

Table F-2 Subchronic, Chronic and Other Toxicity Profile for Tolfenpyrad

Type of 

Study/Gui

de line

Study Title MRID Results

870.6200a Acute 

Neurotoxicity, Rat 

(gavage)

47447831 Levels tested: 0, 20, 40, 60 mg/kg/day in males and 0, 10, 20, or 

40 mg/kg/day in females.

NOAEL (M/F) = 10 mg/kg/day

LOAEL (M/F) = 20 mg/kg/day, based on decreases in body 

weight, body weight gain and food consumption in females.

870.6200b Subchronic 

Neurotoxicity, Rat 

(feeding

47447830 0, 15, 40, 80 ppm or 0/0, 1/1.2, 2.7/3.2, 5.4/6 mg/kg/day

NOAEL (M/F) =40 ppm or 2.7/3.2 mg/kg/day

LOAEL (M/F) = 80 ppm or 5.4/6 mg/kg/day, based on decreased 

body weights, body weight gains, and food consumption

870.6300 Developmental 

Neurotoxicity, Rat 

No study Available: Waiver request submitted

870.7485 Metabolism, Rat 47447837, 47447836, 

47447834, 47447833, and 

47447835

The test compound was rapidly absorbed and 

excreted. Total recoveries ranged from 91.3-99.6% 

of the administered dose (AD) across all groups and 

in both sexes. Feces were the predominant route of 

excretion. Across all single dose groups, 88.2-

93.2% AD was excreted in the feces and 1.7-3.0% 

AD was eliminated in the urine. Negligible 

amounts of radioactivity were recovered in the 

expired air and cage wash, both accounting for 

≤0.1% AD. In the bile duct-cannulated rats at 48 h 

post-dosing, the majority of radioactivity was 

excreted in the bile (51.3-69.5% AD), with minor 

amounts eliminated in the feces (3.5-8.3% AD) and 

urine (0.7-3.0% AD), indicating that bile was the 

primary route of excretion for the absorbed test 

material. Absorption (defined as radioactivity found 

in the bile, urine, cage wash, and carcass) was 

greater in males (72.8-77.8% AD) than in females 

(57.9-69.4% AD). Females also had more 

radioactivity remaining in the gastrointestinal tract, 

and the amount remaining increased with dose.

870.7600 Dermal 

Penetration, Rat

47447839 At 24 hours in the 1 g/L group, the dermal 

absorption is 13%.

Non 

guideline

New data

Comparative in 

vitro dermal 

absorption study 

using human and 

rat skin

48233401 At 24 hrs, the total absorbed dose (absorbed + 

absorbable dose) at the high dose was 1.12% in 

human skin and 26.78% in rats skin. At the low 

dose, the total absorbed dose was 6.49% in human 

skin and 67.02% in rat skin. 

870.7800 Developmental 

Immunotoxicity, 

Rat (feeding)

47447840 Levels tested: 0, 0.75, 3 mg/kg/day

Maternal NOAEL = 0.75 mg/kg/day

Maternal LOAEL = 3 mg/kg/day, based on 

decreased body weight (up to 10%), body weight 

gain (up to 36%), and food consumption in the P 

generation

Offspring NOAEL = 0.75 mg/kg/day

Offspring LOAEL = 3 mg/kg/day, based on 

decreased survival, body weight, and body weight 

gains; increased incidence of blackish abdominal 

cavity and dark green abnormal intestinal content; 
107

Table F-2 Subchronic, Chronic and Other Toxicity Profile for Tolfenpyrad

Type of 

Study/Gui

de line

Study Title MRID Results

and decreased thymus and spleen weights in the F1 

and/or F2 generations 

Note: No treatment-related effects noted on the 

immune system.
108

Appendix G. ECOSAR Output for Tolfenpyrad and Metabolites

1. ECOSAR Results for TOLFENPYRAD using ESTIMATED Log Kow of 6.45

SMILES : N(Cc3ccc(Oc2ccc(C)cc2)cc3)C(=O)c1c(CL)c(CC)nn1C

CHEM : tolfenpyrad

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C21 H22 CL1 N3 O2 

MOL WT : 383.88

Log Kow: 6.45 (KowWin estimate)

Melt Pt: 

Wat Sol: 0.01186 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Amides 

Pyrazoles/Pyrroles 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== 

Amides : Fish 96-hr LC50 0.015 *

Amides : Daphnid 48-hr LC50 0.039 *

Amides : Green Algae 96-hr EC50 0.048 *

Amides : Fish ChV 8.77e-005

Amides : Daphnid ChV 0.000513 !

Amides : Green Algae ChV 0.641 *

Pyrazoles/Pyrroles : Fish 96-hr LC50 0.009

Pyrazoles/Pyrroles : Daphnid 48-hr LC50 0.088 *

Pyrazoles/Pyrroles : Fish ChV 0.00134 !

Pyrazoles/Pyrroles : Daphnid ChV 0.004 !

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 0.050 *

(Baseline Toxicity) : Daphnid 48-hr LC50 0.050 *

 : Green Algae 96-hr EC50 0.133 *

 : Fish ChV 0.004

 : Daphnid ChV 0.010

 : Green Algae ChV 0.109 *
109

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000
110

2. ECOSAR Results for TOLFENPYRAD using MEASURED Log Kow of 4.3

SMILES : N(Cc3ccc(Oc2ccc(C)cc2)cc3)C(=O)c1c(CL)c(CC)nn1C

CHEM : tolfenpyrad

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C21 H22 CL1 N3 O2 

MOL WT : 383.88

Log Kow: 4.30 (User entered)

Melt Pt: 

Wat Sol: 0.8191 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Amides 

Pyrazoles/Pyrroles 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== 

Amides : Fish 96-hr LC50 0.750

Amides : Daphnid 48-hr LC50 0.935 *

Amides : Green Algae 96-hr EC50 0.193

Amides : Fish ChV 0.004

Amides : Daphnid ChV 0.012 !

Amides : Green Algae ChV 0.641

Pyrazoles/Pyrroles : Fish 96-hr LC50 0.140

Pyrazoles/Pyrroles : Daphnid 48-hr LC50 0.578

Pyrazoles/Pyrroles : Fish ChV 0.018 !

Pyrazoles/Pyrroles : Daphnid ChV 0.033 !

=========================== ================== ======== 

Neutral Organic SAR : Fish 96-hr LC50 3.347 *

(Baseline Toxicity) : Daphnid 48-hr LC50 2.550 *

 : Green Algae 96-hr EC50 2.825 *

 : Fish ChV 0.302

 : Daphnid ChV 0.354

 : Green Algae ChV 1.556 *
111

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000
112

3. ECOSAR Results for PT-CA using ESTIMATED Log Kow of 5.79

SMILES : N(Cc3ccc(Oc2ccc(cc2)C(=O)(O))cc3)C(=O)c1c(CL)c(CC)nn1C

CHEM : PT-CA

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C21 H20 CL1 N3 O4 

MOL WT : 413.86

Log Kow: 5.79 (KowWin estimate)

Melt Pt: 

Wat Sol: 0.02864 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Amides -acid

Pyrazoles/Pyrroles -acid

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== 

--> Acid moeity found: Predicted values multiplied by 10

Amides -acid : Fish 96-hr LC50 0.538 *

Amides -acid : Daphnid 48-hr LC50 1.121 *

Amides -acid : Green Algae 96-hr EC50 0.801 *

Amides -acid : Fish ChV 0.003

Amides -acid : Daphnid ChV 0.015 !

Amides -acid : Green Algae ChV 6.914 *

Pyrazoles/Pyrroles -acid : Fish 96-hr LC50 0.226 *

Pyrazoles/Pyrroles -acid : Daphnid 48-hr LC50 1.698 *

Pyrazoles/Pyrroles -acid : Fish ChV 0.033 *!

Pyrazoles/Pyrroles -acid : Daphnid ChV 0.078 *!

=========================== ================== ======== 

Neutral Organic SAR : Fish 96-hr LC50 0.199 *

(Baseline Toxicity) : Daphnid 48-hr LC50 0.181 *

 : Green Algae 96-hr EC50 0.370 *

 : Fish ChV 0.017

 : Daphnid ChV 0.033 *

 : Green Algae ChV 0.267 *

Note: * = asterisk designates: Chemical may not be soluble
113

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000
114

4. ECOSAR Results for PAM using ESTIMATED Log Kow of 1.68

SMILES : NC(=O)c1c(CL)c(CC)nn1C

CHEM : PAM

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C7 H10 CL1 N3 O1 

MOL WT : 187.63

Log Kow: 1.68 (KowWin estimate)

Melt Pt: 

Wat Sol: 1869 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Amides 

Pyrazoles/Pyrroles 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== 

Amides : Fish 96-hr LC50 43.539

Amides : Daphnid 48-hr LC50 21.932

Amides : Green Algae 96-hr EC50 0.507

Amides : Fish ChV 0.257

Amides : Daphnid ChV 0.289 !

Amides : Green Algae ChV 0.313

Pyrazoles/Pyrroles : Fish 96-hr LC50 1.943

Pyrazoles/Pyrroles : Daphnid 48-hr LC50 2.799

Pyrazoles/Pyrroles : Fish ChV 0.216 !

Pyrazoles/Pyrroles : Daphnid ChV 0.224 !

=========================== ================== ======== 

Neutral Organic SAR : Fish 96-hr LC50 271.434

(Baseline Toxicity) : Daphnid 48-hr LC50 150.621

 : Green Algae 96-hr EC50 56.866

 : Fish ChV 25.952

 : Daphnid ChV 13.139

 : Green Algae ChV 19.400

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.
115

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000
116

5. ECOSAR Results for PCA using ESTIMATED Log Kow of 2.17

SMILES : OC(=O)c1c(CL)c(CC)nn1C

CHEM : PCA

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C7 H9 CL1 N2 O2 

MOL WT : 188.61

Log Kow: 2.17 (KowWin estimate)

Melt Pt: 

Wat Sol: 700 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Pyrazoles/Pyrroles -acid

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== 

--> Acid moeity found: Predicted values multiplied by 10

Pyrazoles/Pyrroles -acid : Fish 96-hr LC50 10.406

Pyrazoles/Pyrroles -acid : Daphnid 48-hr LC50 18.275

Pyrazoles/Pyrroles -acid : Fish ChV 1.193 !

Pyrazoles/Pyrroles -acid : Daphnid ChV 1.368 !

=========================== ================== ======== 

Neutral Organic SAR : Fish 96-hr LC50 104.292

(Baseline Toxicity) : Daphnid 48-hr LC50 61.431

 : Green Algae 96-hr EC50 28.400

 : Fish ChV 9.863

 : Daphnid ChV 5.847

 : Green Algae ChV 10.603

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical
117

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

6. ECOSAR Results for PT(A)-4-OH using ESTIMATED Log Kow of 3.37

SMILES : CCc1nn(C)c(C(=O)NCc2ccc(O)cc2)c1CL

CHEM : (PT(A)-4-OH)

CAS Num: 

ChemID1: 

ChemID2: 
118

ChemID3: 

MOL FOR: C14 H16 CL1 N3 O2 

MOL WT : 293.76

Log Kow: 3.37 (KowWin estimate)

Melt Pt: 

Wat Sol: 67.2 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

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

Phenols

Amides 

Phenol Amines 

Pyrazoles/Pyrroles 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Phenols : Fish 96-hr LC50 4.347

Phenols : Fish 14-day LC50 14.579

Phenols : Daphnid 48-hr LC50 2.571

Phenols : Green Algae 96-hr EC50 10.350

Phenols : Fish 30-day ChV 0.491

Phenols : Fish 60-day ChV 0.009

Phenols : Daphnid 21-day ChV 0.488

Phenols : Green Algae ChV 4.779

Phenols : Fish (SW) 96-hr LC50 1.391

Phenols : Earthworm 14-day LC50 75.119 *

Phenols : Lemna Gibba 7-day EC50 2.359

Amides : Fish 96-hr LC50 3.120

Amides : Daphnid 48-hr LC50 2.821

Amides : Green Algae 96-hr EC50 0.268

Amides : Fish ChV 0.018

Amides : Daphnid ChV 0.037 !

Amides : Green Algae ChV 0.491

Phenol Amines : Fish 96-hr LC50 3.276

Phenol Amines : Daphnid 48-hr LC50 1.014

Phenol Amines : Green Algae 96-hr EC50 1.524

Phenol Amines : Fish ChV 0.076 !

Phenol Amines : Daphnid 21-day ChV 0.084

Phenol Amines : Green Algae ChV 0.347

Pyrazoles/Pyrroles : Fish 96-hr LC50 0.351

Pyrazoles/Pyrroles : Daphnid 48-hr LC50 0.997

Pyrazoles/Pyrroles : Fish ChV 0.043 !

Pyrazoles/Pyrroles : Daphnid ChV 0.064 !

=========================== ================== ======== 

Neutral Organic SAR : Fish 96-hr LC50 15.679

(Baseline Toxicity) : Daphnid 48-hr LC50 10.677

 : Green Algae 96-hr EC50 8.076

 : Fish ChV 1.444

 : Daphnid ChV 1.256

 : Green Algae ChV 3.754

Note: * = asterisk designates: Chemical may not be soluble
119

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Phenols:

-------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 7.0 (Fish 96-hr LC50, Daphnid LC50)

Maximum LogKow: 6.4 (Fish 14-day LC50, Earthworm, Lemna)

Maximum LogKow: 7.0 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum LogKow: 5.0 (Fish (SW) 96-hr LC50, Mysid)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Phenol Amines :

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

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50)

Maximum LogKow: 7.0 (Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Pyrazoles/Pyrroles :

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

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.
120

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

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

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

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

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000 
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Appendix H

Endangered Species Policy and Considerations

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 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 it authorizes, funds, or carries 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 2004a). 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. If listed or candidate species may be present 

in the proposed 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 proposed registration of new uses for tolfenpyrad. It is 

expected that the new uses of tolfenpyrad will occur nationwide.
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5.3.1 Action Area

For listed species assessment purposes, the action area is considered to be the area affected 

directly or indirectly by tolfenpyrad use and not merely the immediate area where tolfenpyrad is 

applied. At the initial screening-level, the risk assessment considers broadly described taxonomic 

groups and conservatively assumes that listed species within those broad groups 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. The assessment also assumes that the listed 

species are located within an assumed area, which has the relatively highest potential exposure to 

the pesticide, and that exposures are likely to decrease with distance from the treatment area. 

Section 5.3.4 of this risk assessment presents the proposed pesticide use sites that are used to 

establish initial co-location of species with treatment areas.

5.3.2 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 that 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 the proposed new 

tolfenpyrad uses, and the associated exposure and effects analyses conducted for the tolfenpyrad 

screening-level risk assessment are in Sections 3 to 4. 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 non-target aquatic and terrestrial plant species from exposure via 

spray drift and runoff. These assessment endpoints address the standard set forth in the 

Endangered Species Act requiring federal agencies to ensure that any action it authorizes 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 (RQ 

values) integrating exposure and effects are calculated for broad-based taxonomic groups in the 

screening-level risk assessment and are presented in Section 5.
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Both acute and chronic risk to listed species LOCs are considered in the screening-level risk 

assessment to identify direct and indirect effects to taxa of listed species. This section identifies 

direct and indirect effect concerns, by taxa, that are triggered by exceeding listed species LOCs 

in the screening-level risk assessment (Table 5.12). Data on exposure and effects collected 

under field (when available) and laboratory conditions are evaluated to make determinations on 

the predictive utility of the direct effect screening assessment findings to listed species. 
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Appendix I

Bird Species Utilizing Proposed Crop areas for Nesting

The following information is based on the American Bird Conservancy efforts to document the presence 

of various species by agricultural areas as recorded in surveys and published open literature. Both the 

county locations and time of year are included for these observations, but the summaries below were 

shortened to simply illustrate the species which may be exposed from proposed uses of Tolfenpyrad. It 

should not be considered a comprehensive list for all potential bird species that might nest in these crop 

areas, but rather an indication of the diversity of species that utilize crop areas for nesting and brood 

rearing of young.

Birds Observed Nesting in Citrus Groves

Common Ground-Dove, Common Nighthawk, Common Pauraque, Eastern meadowlark, Eastern 

Towhee, Great tailed Grackle, Inca dove, Loggerhead shrike, Long billed thrasher, Mourning dove, 

Northern bobwhite, Northern Cardinal, Northern mockingbird, Red-winged blackbird, White tipped dove, 

White winged dove, Yellow-billed cuckoo. In addition, 46 species were observed foraging in citrus 

groves 

Bird Species Observed Nesting in Orchard Crops

American crow, American goldfinch, American redstart, American robin, Baltimore oriole, Barn 

swallow, Black-billed cuckoo, Black crowned Night Heron, Brown thrasher, Brown-headed cowbird, 

Cassin’s Kingbird (brood rearing and nesting), Cedar waxwing, Chipping sparrow, Common grackle, 

Common ground dove, Dickcissel, eastern bluebird, Eastern Kingbird, Eastern towhee, European 

starling, Gray catbird, House finch, House wren, Least flycatcher, Loggerhead shrike, Mourning dove, 

Northern cardinal, Northern mockingbird, Orange-crowned Warbler, Red-winged Blackbird, Savannah 

Sparrow, Song Sparrow, Tree Swallow, Western Kingbird, White-tailed Kite, Wood thrush In addition, 

162 species were observed foraging in orchards

Bird Species Observed Nesting in Pome Fruit Orchards

American Crow, American Goldfinch, American Redstart, American Robin, American woodcock (brood 

rearing), Baltimore Oriole, Barn Swallow, Black-billed Cuckoo, Brown Thrasher, Brown-headed 

Cowbird, Cassin's Kingbird (nesting and brood rearing), Cedar Waxwing, Chipping Sparrow, Common 

Grackle, Eastern Bluebird, Eastern Towhee, European Starling, Gray Catbird, House Finch, House Wren, 

Indigo Bunting (nesting and brood Rearing), Least Flycatcher, Loggerhead Shrike, Mourning Dove, 

Northern Cardinal, Northern Mockingbird, Orange-crowned Warbler, Savannah Sparrow, Song Sparrow, 

Tree Swallow, Western Kingbird (nesting and brood rearing), Wood thrush, In addition, 133 species 

were observed foraging in pome fruit orchards

Bird Species Observed Nesting in Stone fruit Orchards 

American crow, American robin, Dickcissel with 30 species observed foraging in stone fruit orchards.

Birds Observed Nesting in Nut Crop Orchards

American Crow, with 15 species observed foraging in nut crops

Birds Observed Nesting in Fruiting vegetables and Curcurbits Mottled duck with 12 species observed 

foraging in these crops

Birds Observed Nesting in Cotton

Greater prairie chicken (Aransas County, TX; Refugio County, TX)
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