Environmental Fate and Ecological Risk Assessment 

for the Registration of Penflufen 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

Penflufen 

N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-carboxamide 

CAS Registry Number: 494793-67-8 

PC Code: 100249 

 

Prepared by:

Reuben D. Baris, Environmental Scientist 

Brian D. Kiernan, Biologist 

U. S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington DC 20460

Reviewed by: 

Melissa Panger, Ph.D, Senior Biologist ERB III 

William P. Eckel, Ph.D, Senior Science Advisor, ERB VI 

Mark Corbin, Branch Chief, ERB VI 

Date: November 23, 2011 
-Page 2 of 115- 

Table of Contents

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

1.1. Nature of Chemical Stressor ........................................................................................................ 4

1.2. Potential Risks to Non-target Organisms .................................................................................... 4

1.3. Conclusions - Exposure Characterization .................................................................................... 5

1.4. Conclusions - Effects Characterization ....................................................................................... 6

2. Problem Formulation ......................................................................................................................... 8

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

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

2.2.1. Nature of Chemical Stressor ................................................................................................. 8

2.2.2. Overview of Pesticide Usage .............................................................................................. 10

2.3. Receptors ................................................................................................................................... 10

2.3.1. Aquatic and Terrestrial Effects ........................................................................................... 10

2.3.2. Ecosystems Potentially at Risk ........................................................................................... 11

2.4. Assessment Endpoints ............................................................................................................... 11

2.5. Conceptual Model ...................................................................................................................... 11

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

2.5.2. Conceptual Diagram ........................................................................................................... 12

2.6. Analysis Plan ............................................................................................................................ 14

2.6.1. Residues of Concern ........................................................................................................... 14

2.6.2. Preliminary Identification of Data Gaps and Uncertainties ................................................ 14

2.6.3. Evaluation of Multiple Active Ingredients and Mixtures .................................................... 15

2.6.4. Measures of Exposure ......................................................................................................... 15

2.6.5. Measures of Effect .............................................................................................................. 16

2.6.6. Integration of Exposure and Effects .................................................................................... 18

3. Analysis ........................................................................................................................................... 19

3.1. Use Characterization.................................................................................................................. 19

3.2. Exposure Characterization ......................................................................................................... 20

3.2.1. Environmental Fate and Transport Characterization .......................................................... 20

3.2.2. Measures of Aquatic Exposure ........................................................................................... 29

3.2.3. Measures of Terrestrial Exposure ....................................................................................... 35

3.3. Ecological Effects Characterization .......................................................................................... 36

3.3.1. Aquatic Toxicity Assessment .............................................................................................. 37

3.3.2 Terrestrial Effects Characterization .................................................................................... 46

4. Risk Characterization ...................................................................................................................... 56

4.1. Risk Estimation ......................................................................................................................... 56

4.1.1. Aquatic Organisms .............................................................................................................. 57

4.1.2. Terrestrial Organisms .......................................................................................................... 58

4.2. Risk Description ........................................................................................................................ 60

4.2.1 Exposure to Aquatic Organisms ......................................................................................... 60

4.2.2 Risks to Aquatic Animals ................................................................................................... 61

4.2.3 Risks to Aquatic Plants ....................................................................................................... 63

4.2.4. Risks to Mammals ............................................................................................................... 64

4.2.5. Risk to Birds ....................................................................................................................... 64

4.2.6. Potential Effects on Terrestrial Invertebrates ...................................................................... 65

4.2.7. Risk to Terrestrial Non-target Plants................................................................................... 66

4.3. Uncertainties and Data Gaps ..................................................................................................... 67

4.3.1. Fate and Transport .............................................................................................................. 67
-Page 3 of 115- 

4.3.2. Effects Uncertainties ........................................................................................................... 67

4.3.3. Aquatic Exposure ................................................................................................................ 68

5. Federally Threatened and Endangered (Listed) Species Concerns ............................................. 69

5.1. Action Area ............................................................................................................................... 70

5.2. Taxonomic Groups Potentially at Risk ...................................................................................... 70

5.2.1. Probit Dose-Response Analysis .......................................................................................... 72

5.2.2. Listed Species Occurrence Associated with Penflufen Use ................................................ 73

6. References ......................................................................................................................................... 74

6.1. Submitted Product Chemistry and Environmental Fate Studies ................................................ 75

6.2. Submitted Ecotoxicity Studies ................................................................................................... 77

Appendix A. Chemical Names, Structures, and Maximum Reported Amounts of Penflufen and Its 

Degradates. ................................................................................................................................................ 86

Appendix B. Tier 2 Summary Catalog of Submitted Ecological Effects Studies for Penflufen. ....... 91

Appendix C. Catalogue of Submitted Environmental Fate Studies for Penflufen. ............................ 96

Appendix D. Product Chemistry and Environmental Fate Summary of Penflufen ........................ 100

Appendix E. Aquatic Model Input/Output Data. ................................................................................ 108

Appendix F. Federally Listed Species Potentially at Risk from the Proposed Uses of Penflufen ... 111
-Page 4 of 115- 

1. Executive Summary 

1.1. Nature of Chemical Stressor 

Bayer CropScience is seeking registration for the new chemical fungicide penflufen (BYF 

14182; N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-carboxamide;

CAS#: 494793-67-8; PC code: 100249). Penflufen is a succinate dehydrogenase inhibitor 

(SDHI) in the pyrazole carboxamide class of chemicals. It is proposed for use as a fungicide seed 

treatment for protection against certain soilborne, seedborne, and post-emergence diseases of 

crop plants. 

This assessment is for a national registration request for the following seed treatment uses: 

alfalfa, beans and peas (including soybeans), canola, mustard (oilseed and condiment), rapeseed, 

cotton, cereal grains, corn, sorghum, sunflower, safflower, potato seed pieces, and rice (not for 

application to flooded fields). In addition, Bayer is proposing an in-furrow spray application for 

potato and other tuberous corm vegetables at planting in combination with the treatment of seed 

pieces or seed. Maximum application rates range from 0.001 to 0.28 lbs a.i./A/yr. This 

assessment is based on proposed maximum application rates for all uses. 

Seven end-use formulations of penflufen are proposed for registration in the United States. 

Some of the proposed labels include multiple co-formulated currently registered active 

ingredients for use as seed treatments (e.g., penflufen plus clothianidin, trifloxystrobin, 

metalaxyl, or prothioconazole). The Agency does not routinely include an evaluation of 

mixtures of active ingredients in its risk assessments. In the case of the product formulations of 

active ingredients (that is, a registered product containing more than one active ingredient), each 

active ingredient is subject to an individual risk assessment for regulatory decision regarding the 

active ingredient for a particular use site. However, acute mammalian toxicity data are available 

for several combinations of active ingredients used in proposed products and no toxic effects are 

reported. Data on coformulants are not available for any other taxa. 

Major transformation products resulting from the environmental degradation of penflufen are 

penflufen-3-hydroxy-butyl (pen-3HB), penflufen-pyrazolyl-AAP (AAP), and under certain 

circumstances, BYF 14182-fluoro acidand carbon dioxide. Eco-toxicity data are available for 

pen-3HB and AAP showing that pen-3HB and AAP are no more, and often less, toxic compared 

to the technical grade active ingredient (TGAI), based on the most sensitive taxa tested. Aquatic 

exposure estimates are thus based on exposure from penflufen penflufen alone. Terrestrial 

exposure estimates are based on the residue levels of the parent compound alone. 

1.2. Potential Risks to Non-target Organisms 

The results of this screening-level assessment on the proposed penflufen uses indicate that risk of 

adverse effects to non-target organisms is generally not expected. However, because a NOAEC 

was not determined in the available mallard duck (Anas platyrhynchos) reproduction study, risk 

from chronic exposure to listed and non-listed birds, reptiles and terrestrial-phase amphibians 
-Page 5 of 115- 

cannot be precluded. Additionally, the proposed use as a treatment for rice seed results in an RQ 

equal to the listed species acute LOC for fish and surrogates (aquatic-phase amphibians). 

Table 1.1. Potential Effects to Federally Listed Taxa Associated with Direct or Indirect 

Effects from the Proposed New Uses of Penflufen.

Listed Taxon Direct Effects Indirect Effectsa

Terrestrial and semi-aquatic plants - monocots No Yes

Terrestrial and semi-aquatic plants - dicots No Yes

Birds Yes Yes

Terrestrial-phase amphibians and reptiles Yes Yes

Mammals No Yes

Aquatic nonvascular plants No Yes

Aquatic vascular plants No Yes

Freshwater fish Yes Yes

Aquatic-phase amphibians Yes Yes

Freshwater crustaceans No Yes

Mollusks No Yes

Marine/estuarine fish No Yes

Marine/estuarine invertebrates No Yes a

until an endangered species assessment is complete, indirect effects to all species cannot be precluded 

1.3. Conclusions - Exposure Characterization 

Penflufen is expected to persist in both terrestrial and aquatic environments under aerobic and 

anaerobic conditions, and is considered moderately mobile, lipophilic, and nonvolatile. 

Penflufen is persistent in soil, with half-lives ranging from 115 to 433 days in aerobic soil and 

extrapolated half-lives of nearly two and a half years in anaerobic soil. There is no evidence of 

degradation via hydrolysis, which was studied across environmental pHs. Laboratory data show 

that penflufen degraded slowly by aerobic aquatic metabolism with half-lives ranging from 267 

to 301 days. A potentially major route of degradation in shallow, clear waters (e.g., applications 

to flooded rice paddies) may be aqueous photolysis (environmental half-life of 83 days); 

however photolysis is slow and plays a significant role in shallow clear waters. Penflufen does 

not bioconcentrate in aquatic organisms. 

Aquatic exposure estimates are based on the exposure of the parent compound penflufen only. 

There were significant amounts of unextracted residues reported in the metabolism studies, and 

multiple extraction solvents were not explored. The applicant submitted supplemental data 

characterizing the unextracted residues addressing the uncertainty about whether or not the 

unextracted residues are parent. The study compared extractions in sterile (gamma-irradiated) 

and non-sterile (viable) soils (MRID 48652501). These data suggest that a large portion of the 

unextracted residues reported in the metabolism studies are biologically mediated and are 

hypothesized to be irreversibly bound. Therefore, conservative aquatic exposure estimates were 

generated using environmental half-lives for the parent only. 

Modeled uses include the potato seed piece treatment and combined in-furrow spray, peas and 

bean seed treatment (including legumes and soybeans), and the rice seed treatment. These uses 

result in the maximum exposure for each type of application method. Therefore, they provide 
-Page 6 of 115- 

conservative estimates of exposure for the proposed uses with lower application rates and similar 

application methods that were not modeled. The range of all proposed uses are listed in Table 

3.1. 

Acute 1-in-10 year estimated environmental concentrations (EECs) in surface water (for parent + 

unextracted residues) for all modeled uses of penflufen ranged from 1.13 μg/L to 4.71 μg/L. 

Use for rice seed resulted in an exceedence of the level of concern (LOC) for listed fish (an EEC 

of 4.71 μg/L for rice). A reduction in the application rate for rice from 0.006 lbs a.i./A to 0.005 

lbs a.i./A would reduce the peak EEC from 4.71 μg/L to 3.93 μg/L, which would mitigate the 

exceedance for listed fish described above in Section 1.2. 

Terrestrial exposure estimates are based on the residue levels of penflufen on seed alone, as 

described above. The in-furrow treatment for seed pieces is treated as an additional seed 

treatment in this assessment, in that the seed piece per acre rate and the in-furrow per acre rate 

are added together to generate a conservative estimate of exposure. Seeding rates were used to 

calculate a dose on a per area basis of treated seed that terrestrial animals may use as forage 

items. Penflufen is locosystemic and is not transported acropetally in foliage as the plants 

emerge and grow; therefore the greatest exposure is expected from animals directly ingesting 

treated seed. 

1.4. Conclusions - Effects Characterization 

Aquatic Organisms 

Results of acute toxicity studies in freshwater and estuarine/marine fish indicate that penflufen is 

highly to very highly toxic to fish on an acute exposure basis. Dose-dependent sublethal effects 

observed in fish studies included surfacing, lethargy, erratic swimming, loss of equilibrium, loss 

of vertical orientation, labored respiration, and lying on the bottom. Reduced fish length was 

observed in the F1 generation of the available early life-stage (ELS) study. Acute toxicity 

studies indicate that penflufen is moderately toxic to freshwater and estuarine/marine 

invertebrates on an acute exposure basis. Quiescence, pale color and abnormal positioning were 

the reported sublethal effects in invertebrates. Penflufen has effects on aquatic vascular and 

nonvascular plants, with biomass and cell density being adversely affected. 

Degradate toxicity data on fish, aquatic invertebrates and green algae indicate that penflufen 

degradates are less toxic than the parent and effects are not expected at environmentally relevant 

concentrations. 

Terrestrial Organisms 

Penflufen is practically non-toxic to Norway rat (Rattus norvegicus) on an acute exposure basis. 

A two-generation study on reproduction and fertility in the rat showed penflufen to cause chronic 

toxicity effects in the parents and F1 and F2 generations that would impact adult body weights 

and reduced litter size. 
-Page 7 of 115- 

Studies of acute oral (dose-based) toxicity in bobwhite quail (Colinus virginianus) and canary 

(Serinus canaria) indicated that penflufen is practically nontoxic to bobwhite quail and canary 

when administered as a single oral dose. Two subacute dietary toxicity studies indicate that 

penflufen TGAI is also practically nontoxic to mallard duck and bobwhite quail on a subacute 

dietary exposure basis. For chronic effects, there were treatment-related effects on the number of 

eggs hatched per live embryo at all tested concentrations in the reproduction toxicity study of 

penflufen TGAI in mallard duck; no endpoint (i.e., NOAEC) was derived in the study. No 

effects were reported in the bobwhite quail study. No studies of the formulations or the 

degradates were submitted for birds; all measurement endpoints for avian species are based on 

technical grade penflufen. 

Results of available toxicity studies indicate that penflufen TGAI is practically nontoxic to honey 

bees (Apis mellifera) on an acute exposure basis, though there are effects on the fecundity of 

Aphidius rhopalosiphi, a parasitoid wasp, and earthworms (Eisenia foetida) on an acute contact 

exposure basis. It is not clear from the available data whether there would be effects on larval 

bee pollinators or what the route of exposure would likely be. However, a study on larval bees 

would reduce this uncertainty. 

Tier I limit studies of the effect of the penflufen formulation PEN 240FS on seed emergence and 

vegetative vigor in terrestrial plants were submitted, indicating that terrestrial plants are 

relatively insensitive to penflufen at application rates slightly less than the maximum per acre 

application rate for the proposed registration uses. 
-Page 8 of 115- 

2. Problem Formulation 

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

ecological risk assessment for the registration of the new chemical penflufen, (BYF 14182; N-[2-

(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-carboxamide; CAS#: 494793-

67-8; PC code: 100249). The problem formulation sets the objectives for the risk assessment, 

establishes a risk hypothesis and conceptual model depicting potential risk, and provides a plan 

for analyzing the data and characterizing the risk associated with the proposed use of penflufen 

(USEPA, 1998). 

2.1. Nature of Regulatory Action 

The U.S. Environmental Protection Agency (EPA or the Agency) is required under the Federal 

Insecticide, Fungicide, and Rodenticide Act (FIFRA) to ensure that the newly proposed use of 

penflufen as a fungicide does not have the potential to cause unreasonable adverse effects to the 

environment. In addition to non-target animals and plants, potential effects to listed species (i.e., 

species on the Federal list of endangered and threatened wildlife and plants) and their designated 

critical habitat are also considered under the Endangered Species Act (ESA) in order to ensure 

that the registration of penflufen is not likely to jeopardize the continued existence of listed 

species or adversely modify their critical habitat. In order to meet the requirements of FIFRA 

and the ESA, this assessment follows EPA guidance on conducting ecological risk assessments 

(USEPA, 1998) and Office of Pesticide Program’s Overview Document, which contains 

guidance for assessing pesticide risks to non-target and listed organisms (USEPA, 2004). 

The end result of the EPA pesticide registration process (i.e., the FIFRA regulatory action) is an 

approved (or disapproved) product label. The label is a legal document that stipulates how and 

where a given pesticide may be used. Product labels (also known as end-use labels) describe the 

formulation type (e.g., liquid or granular), acceptable methods of application, approved use sites, 

and any restrictions on how applications may be conducted. Therefore, the use, or potential use, 

described by the pesticide’s labels is considered “the action” being assessed. This assessment 

was prepared to support evaluation of the proposed new chemical registration of penflufen. 

2.2. Stressor Source and Distribution 

2.2.1. Nature of Chemical Stressor 

Bayer CropScience is seeking registration for the use of the new chemical fungicide penflufen 

(BYF 14182), N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-

carboxamide. According to Bayer, penflufen is a locosystemic fungicide (i.e., is available in the 

cells of new sprouts but is not transported in xylem or phloem) that is intended to inhibit 

mitochondrial respiration by blocking electron transport in the respiratory chain of succinate 

dehydrogenase (i.e., the compound is a succinate dehydrogenase inhibitor or SDHI). Penflufen 

is intended to provide protection to seedlings against fungal pathogens by acting on spore 

germination, germ tube elongation, and mycelium growth. This assessment is part of a national 
-Page 9 of 115- 

registration request for a fungicide seed treatment for protection against certain soilborne, 

seedborne, and post-emergence fungal diseases of crop plants. 

Penflufen is in the pyrazole carboxamide family of fungicides. Bayer is proposing the following 

seed treatment uses: alfalfa, beans and peas (including soybeans), canola, mustard (oilseed and 

condiment), rapeseed, cotton, cereal grains, corn, sorghum, sunflower, safflower, potato seed 

pieces, and rice (not for use in flooded fields). In addition, Bayer is proposing an in-furrow spray 

application for potato and other tuberous corm vegetables at planting in combination with the 

treatment of seed pieces or seed. This assessment is based on proposed maximum application 

rates for all uses. 

Seven end-use formulations of penflufen are proposed for registration in the United States. They 

include the following: 

1. PEN 240FS: 22.7% penflufen, used as a seed treatment for alfalfa, beans and peas 

(including soy), canola and other oilseed crops, cotton, cereal grains, corn (field, sweet, 

popcorn), sorghum, sunflower and safflower, rice, potato (seed piece and in-furrow 

application). 

2. PENCLO 273.5FS: 6.0 % penflufen (co-formulated with clothianidin (18.6%)), used to 

treat potato seed pieces, and cotton seed. 

3. PENCLOTRIME 310.68FS: 0.82 % penflufen (co-formulated with clothianidin (22.3%), 

trifloxystrobin (0.55%), and metalaxyl (0.55%)), used to treat canola, rapeseed and 

mustard (oilseed and condiment) seed. 

4. PENPRO 118FS: 9.35 % penflufen (co-formulated with prothioconazole (1.68 %)), used 

to treat potato seed pieces and wheat seed. 

5. PENPROME 177FS: 3.59 % penflufen (co-formulated with prothioconazole (7.18%), 

and metalaxyl (5.74%)), used to treat alfalfa, beans and peas (including soybean), cereal 

grains, and rice seed. 

6. PENRED 240FS: 22.4% penflufen, used as a seed treatment for alfalfa, beans and peas 

(including soy), canola and other oilseed crops, cotton, cereal grains, corn (field, sweet, 

popcorn), sorghum, sunflower and safflower, rice, potato (seed piece and in-furrow 

application). 

7. PENTRI 308FS: 13.3% penflufen (co-formulated with trifloxystrobin (13.3 %), used as a 

seed treatment for alfalfa, beans, wheat, corn, sorghum, cotton, and rice. 

Penflufen is formulated as a flowable concentrate for seed treatment. It is applied primarily to 

seed or potato seed pieces, although the proposed labels recommend an additional in-furrow 

spray for seed piece plantings. The in-furrow application is applied as a near-surface spray 

before the seed pieces (and the in-furrow applied material) are covered in soil. 

The proposed maximum annual application rates are on potato seed pieces. The seed pieces are 

treated at a rate of 0.14 lbs ai/A (based on a seeding rate of 6,969 lbs/A and an application rate of 

0.13 fl oz product/100 lbs of seed). An additional 0.14 lbs ai/A can be applied in-furrow, for a 

total mass applied (on a per acre basis) of 0.28 lbs. Other seed treatments are proposed at lower 

proposed rates as discussed in Section 3.1. 
-Page 10 of 115- 

2.2.2. Overview of Pesticide Usage 

Usage data are not available for penflufen because it is a new active ingredient proposed for use 

in the United States. 

2.3. Receptors 

2.3.1. Aquatic and Terrestrial Effects 

In ecological risk assessment, a receptor is a biological entity that is exposed to a stressor 

(USEPA, 1998). Consistent with the process described in the Overview Document (USEPA, 

2004), this risk assessment uses a surrogate species approach in its evaluation of penflufen. 

Toxicity data generated using surrogate test species, which are intended to be representative of 

broad taxonomic groups, are used to infer potential effects on a variety of species (receptors) 

included under these broader taxonomic groupings. Table 2.1 provides the general taxonomic 

groups and surrogate species tested to evaluate potential ecological effects of penflufen to broad 

classes of non-target organisms. Within each of these taxonomic groups, a measure of effect is 

selected from among the available test data. 

Table 2.1. Taxonomic Groups and Test Species Evaluated for Assessing Potential 

Ecological Effects of Penflufen. 

Taxonomic Group Typical Species 

Birds1 Mallard duck (Anas platyrhynchos) 

Bobwhite quail (Colinus virginianus) 

Mammals Norway rat (Ratus norvegicus) 

Invertebrates Honey bee (Apis mellifera L.) 

Freshwater fish2 Bluegill sunfish (Lepomis macrochirus) 

Rainbow trout (Oncorhynchus mykiss) 

Fathead minnow (Pimephales promelas) 

Freshwater invertebrates Water flea (Daphnia magna) 

Midge (Chironomus riparius) 

Estuarine/marine fish Sheepshead minnow (Cyprinodon variegatus) 

Estuarine/marine invertebrates Mysid (Americamysis bahia) 

Eastern oyster (Crassostrea virginica) 

Terrestrial plants3 Monocots – Crop species, such as corn (Zea mays) 

Dicots – Crop Species, such as soybean (Glycine max)

Aquatic plants and algae Duckweed (Lemna gibba) 

Freshwater Algae (Pseudokirchneriella subcapitata) 1

 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 2

 Freshwater fish may be surrogates for aquatic-phase amphibians. 3

 Four species of two families of monocots, of which one is corn; six species of at least four dicot families, of which one is soybeans.
-Page 11 of 115- 

2.3.2. Ecosystems Potentially at Risk 

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

to identify specific ecosystems during the development of a nation-wide ecological risk 

assessment. However, in general terms, terrestrial ecosystems potentially at risk could include 

the treated field and immediately adjacent areas that may receive drift or runoff. Areas adjacent 

to the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow 

fields or grasslands, woodlands, riparian habitats, and other uncultivated areas. 

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

sites, and might include impounded bodies such as ponds, lakes and reservoirs, or flowing 

waterways such as streams or rivers including all adjacent off-channel habitats that are 

permanently or intermittently connected to flowing waters. For uses in coastal areas, aquatic 

habitat also includes marine ecosystems, including estuaries, embayments, and near-shore 

environments such as tidal marshes. 

Given that the proposed penflufen use is primarily as a seed treatment, exposure to ecosystems 

through spray drift is expected to be minimal, as the in-furrow treatment is sprayed close to the 

ground and immediately covered in 3”-6” of soil. Although the Agency is aware that some 

exposure via dust from abraded seed coat can occur, transport in runoff is likely to be the 

dominant route of ecosystem exposure. 

2.4. Assessment Endpoints 

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

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

(USEPA, 1998). For penflufen, ecological entities of potential concern include the following: 

birds, amphibians, reptiles, mammals, freshwater fish and invertebrates, estuarine/marine fish 

and invertebrates, non-target terrestrial plants, terrestrial invertebrates, and aquatic vascular and 

non-vascular plants. The attributes for each of these entities may include growth, survival, and 

reproduction (Table 2.2 in Section 2.6.4). 

2.5. Conceptual Model 

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

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

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

it must have a source, a release mechanism, an environmental transport mechanism, and a 

feasible route of exposure. 

The conceptual model is intended to provide a written description and visual representation of 

anticipated relationships between penflufen, potential routes of exposure, and the predicted 

effects for the assessment endpoints. The conceptual model consists of two major components: 

risk hypotheses and a conceptual diagram (USEPA, 1998). 
-Page 12 of 115- 

2.5.1. Risk Hypotheses 

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

screening-level risk assessment: 

 

Given the proposed uses of penflufen 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, penflufen results in potential adverse effects 

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

organisms. 

2.5.2. Conceptual Diagram 

The conceptual model is a graphical representation of predicted relationships between ecological 

receptors, both listed (threatened and endangered) and non-listed, and the stressors to which they 

may be exposed. A conceptual model specifies potential routes of exposure, biological receptor 

types, and effects endpoints of potential concern. 

Penflufen is expected to persist in both terrestrial and aquatic environments under aerobic and 

anaerobic conditions, and is considered moderately mobile, lipophilic, and nonvolatile. There is 

no evidence of degradation via hydrolysis. A potentially major route of degradation in shallow, 

clear waters (e.g., applications to flooded rice paddies) may be aqueous photolysis; however 

photolysis is slow and plays a significant role in shallow clear waters. Penflufen has not been 

shown to bioconcentrate in aquatic organisms. 

Penflufen is applied to seeds as a seed treatment. For seed pieces, it is also applied as an infurrow spray, which is covered immediately with 3”-6” in soil. Many seeds are incorporated, but 

given the persistence and mobility of penflufen, the chemical and/or its major degradates may be 

transported off-site in runoff. Ecologically significant spray drift is not expected, the in-furrow 

spray due to its proximity to the soil surface, and is not expected for seed treatments. Figure 2.1 

depicts the stressors, exposure pathways, and potential effects to terrestrial organisms from 

proposed uses of penflufen. Figure 2.2 depicts the stressors, exposure pathways, and potential 

effects to aquatic organisms from proposed uses of penflufen. For both figures, dotted lines 

indicate exposure pathways that are expected to have a low likelihood of contributing to 

ecological risk. 

 

 
-Page 13 of 115- 

Stressor 

Source

Receptors 

Attribute 

Change 

Direct 

application 

Birds / Terrestrialphase amphibians 

/ reptiles / 

mammals

Seeds 

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, terrestrial 

invertebrates 

Runoff 

Mammals

Exposure 

Media 

Soil 

Ingestion 

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion 

Root uptake 

Wet/dry deposition 

Birds / 

Amphibians 

Ingestion 

Penflufen treated seeds and in-furrow spray applied to use site 

Figure 2.1. Conceptual model for penflufen seed treatment effects on terrestrial organisms.
-Page 14 of 115- 

Figure 2.2. Conceptual model for penflufen seed treatment effects on aquatic organisms.

Penflufen treated seeds and in-furrow spray applied to use site 

Fish/aquatic-phase 

amphibians 

Eggs 

Larvae 

Juveniles / Adults 

Individual organisms 

Reduced survival 

Reduced growth 

Reduced reproduction 

Food chain 

Reduction in algae 

Reduction in prey 

Habitat integrity 

Reduction in primary productivity

Reduced cover 

Community change 

Surface water/ 

Sediment 

Runoff 

Uptake/gills 

or integument Aquatic Animals 

Invertebrates 

Vertebrates 

Ingestion Ingestion

Wet/dry deposition 

Soil Groundwater 

Uptake/gills 

or integument 

Aquatic Plants 

Non-vascular 

Vascular 

Uptake/cell, 

roots, leaves Riparian plant

terrestrial 

exposure 

pathways see 

Figure 2.1

Stressor 

Source

Exposure 

Media 

Receptors 

Attribute 

Change 

2.6. Analysis Plan 

2.6.1. Residues of Concern 

Major degradates of penflufen (i.e. those constituting greater than 10% of the applied radiation 

from environmental fate studies) are pen-3HB, AAP, carbon dioxide, and under certain 

circumstances BYF 14182-fluoro acid (chemical names, chemical structures, and data on the 

formation of these degradates are provided in Appendix A). BYF 14182-fluoro acid was 

detected approaching 10% of the applied radioactivity in a submitted aqueous photolysis study. 

Pen-3HB and AAP were not included as residues of concern because available toxicity data 

suggest these degradates are less toxic than the parent such that risk would not be indicated at 

environmentally relevant concentrations. While no toxicity data are available for the fluoro-acid, 

exposure to organisms is expected to be limited, as this degradate was only shown to form via 

aquatic photolysis. Therefore, penflufen alone is the residue of concern in this assessment. 

2.6.2. Preliminary Identification of Data Gaps and Uncertainties 
-Page 15 of 115- 

For the purposes of this assessment, data gaps refer to the absence of necessary data for a 

complete risk assessment. Without eco-toxicity data or evidence to demonstrate otherwise, risk 

to non-listed and listed species of a taxon is presumed. An area of considerable uncertainty for 

this assessment surrounds potential chronic risk to birds. Current data on mallard duck are 

inadequate to derive a definitive NOAEC or make a definitive determination of risk (effects were 

noted at all test concentrations). A second avian reproduction study on mallard duck that results 

in derivation of a NOAEC would reduce uncertainty, and potentially obviate the need to assume 

risk to this taxon. Additionally, three species of nonvascular aquatic plants have not been 

submitted for penflufen, but these data are not thought to be critical to the risk conclusions based 

on data for other carboximide pyrazoles. The adequacy of data for making risk determinations is 

discussed in the context of all lines of evidence in the Risk Characterization. 

 

For the purposes of risk assessment the submitted environmental fate data are not adequate. The 

quality of the submitted data is generally adequate, however some uncertainties exist and are 

discussed in section 4.3. Further a catalog of submitted environmental fate studies for penflufen 

and its degradates, along with justified review classifications, can be found in Appendix C. A 

complete summary of all submitted environmental fate data is included in Appendix D. 

2.6.3. Evaluation of Multiple Active Ingredients and Mixtures 

The Agency does not routinely include in its risk assessments an evaluation of mixtures of active 

ingredients, either those mixtures of multiple active ingredients in product formulations or those 

in the applicator’s tank. In the case of the product formulations of active ingredients (that is, a 

registered product containing more than one active ingredient), each active ingredient is subject 

to an individual risk assessment for regulatory decision regarding the active ingredient on a 

particular use site. If effects data are available for a formulated product containing more than 

one active ingredient, they may be used qualitatively or quantitatively in accordance with the 

Agency’s Overview Document and the Services’ Evaluation Memorandum (U.S. EPA 2004; 

U.S. FWS/NMFS 2004). 

In the case of penflufen, data on the product PEN 240FS are available for fish, aquatic 

invertebrates, nonvascular aquatic plants and mammals. Additionally, data on penflufen and 

coformulants are available for mammals. These are discussed in the effects section (Section 3.3) 

and later in the risk description section (Section 4.2.). 

2.6.4. Measures of Exposure 

Measures of exposure are based on aquatic and terrestrial models that estimate environmental 

concentrations of penflufen using labeled application rates and methods. For aquatic exposure 

the Tier II model Pesticide Root Zone Model (PRZM v3.12.2; May 12, 2005) linked with 

EXposure Analysis Modeling System (EXAMS v2.98.4.6; Apr. 25, 2005) via the 

PRZM/EXAMS model shell (PE v5.0, Nov. 15, 2006), i.e., PRZM/EXAMS) and the Tier I Rice 

Model (v1.0, May 8, 2007) were used to estimate screening-level exposure concentrations in 

aquatic environments. The measure of exposure for aquatic species in surface water bodies 

receiving runoff and/or spray drift is a return frequency of 1-in-10 years of the estimated 
-Page 16 of 115- 

environmental concentrations (EEC), based on 30-year simulations. The maximum 1-in-10 year 

return frequency concentration is used for estimating acute exposures to aquatic organisms 

(plants and animals); the 1-in-10 year 21-day mean concentration is used for assessing aquatic 

invertebrate chronic exposure; and the 1-in-10 year 60-day mean concentration is used for 

assessing chronic exposure for fish (and aquatic-phase amphibians for which fish serve as 

surrogates). Exposure to benthic organisms from sediment concentrations in water bodies was 

assessed; pore-water 1-in-10 year EECs were calculated for maximum use patterns. 

Terrestrial exposure estimates for avian and mammalian risk assessments were derived using the 

T-REX model (version 1.4.1, 10/08/2008). The assumption of the model is that mammals and 

birds may be exposed via their consumption of treated seeds on or immediately adjacent to the 

site of application. The seed treatment worksheet in T-REX calculates the avian and mammalian 

dose (mg a.i. bw-1 day-1) and available pesticide (mg a.i. ft-2). Risk quotients (RQ) are calculated 

using the adjusted LD50 for the smallest weight class of animal (20 g for birds and 15 g for 

mammals). Acute RQs are calculated using two methods: 

Method 1 (EEC/LD50 method): Acute RQ = mg a.i./kg-1 day-1/adjusted LD50

Method 2 (analogous to the LD50 ft-2 method): Acute RQ = mg/kg-1 a.i. ft-2/ (adjusted 

LD50 x body weight (kg)) 

Chronic RQs are calculated using the following equation: 

Chronic RQ = mg a.i. kg-1 seed / NOAEC (mg/kg-diet). 

Exposure for terrestrial plants inhabiting dry and semi-aquatic areas (e.g., low-lying wet areas 

that may dry up at times throughout the year), using TerrPlant v 1.2.1, is based on the following: 

(1) the pesticide's water solubility and the amount of pesticide present on the soil surface 

and its top one centimeter, 

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

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

wetland areas, 

(4) fractional runoff values of 0.01, 0.02, and 0.05 for pesticide water solubilities of <10, 

10-100, and <100 ppm, respectively 

The Screening Imbibition Program (SIP v.1.0) was used to calculate an upper bound estimate of 

wildlife exposure via drinking water using penflufen’s solubility avian and mammalian toxicity 

endpoints. 

2.6.5. Measures of Effect 

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

conducted with a limited number of surrogate test species (Table 2.1). No additional ecotoxicity 

data on penflufen were located, based on an August 2011 query of the open literature in the 

publically available version of the ECOTOX database (http://cfpub.epa.gov/ecotox/). 
-Page 17 of 115- 

The acute measures of effect used in this baseline assessment are the LD50 (median Lethal Dose), 

LC50 (median Lethal Concentration) or EC50 (median Effects Concentration). These are 

measures of acute toxicity which result in 50% of the respective effect in tested organisms. The 

endpoints for chronic measures of exposure are the no observed adverse effect concentration 

(NOAEC) and the no observed adverse effect level (NOAEL). Toxicity studies were submitted 

for freshwater fish and invertebrates, estuarine/marine fish and invertebrates, aquatic plants, 

birds, mammals, bees, and other terrestrial invertebrates. The endpoints used for risk 

characterization are derived from studies which underwent review and were classified as 

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

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

scientifically valid). 

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

potential risks of penflufen to non-target organisms. The methods used to assess the risk are 

consistent with those outlined in the document “Overview of the Ecological Risk Assessment 

Process in the Office of Pesticide Programs” (USEPA, 2004). 
-Page 18 of 115- 

Table 2.2. Measures of Exposure and Measures of Effect Used in Assessing Potential Risks 

Associated with the Proposed Uses of Penflufen. 

Assessment Endpoint Surrogate Species and Measures of 

Ecological Effect1 Measures of Exposure 

Birds2

Survival 

Lowest acute LD50 (single oral dose test) 

and LC50 (subacute dietary test)

Upper-bound residues on 

food items 

Reproduction 

and Growth 

Lowest NOAEC 

 (21-week reproduction test) 

Mammals 

Survival Lowest acute LD50 (single oral dose test)

Reproduction 

and Growth 

Lowest NOAEC 

(2-generation reproduction test) 

Aquatic Animals (Fish and 

invertebrates)3 

Survival Lowest tested LC50 or EC50

(acute toxicity test) 

Peak EECs4

Reproduction 

and Growth 

Lowest NOAEC (early life-stage or full 

life-cycle tests) 

21-day EECs for invertebrates 

and 60-day EECs for fish4 

Terrestrial plants5 Survival and 

growth 

Lowest EC25 (for non-listed plants) and 

corresponding NOAEC (for listed 

plants) 

(endpoints derived for monocots and 

dicots from seedling emergence and 

vegetative vigor studies) 

Estimates of runoff and spray 

drift to non-target areas 

Insects6 Survival (not 

quantitatively 

assessed) 

Lowest honeybee LD50 (acute contact 

test)

Lowest Earthworm LC50 

Maximum application rate for 

honeybees and estimates of 

soil concentrations for 

earthworms 

Aquatic plants (vascular 

and non-vascular) 

Survival and 

growth 

Lowest EC50 (for non-listed plants) and 

corresponding NOAEC or EC05 (for 

listed plants)

Peak EECs4

 

1 The most sensitive species tested within taxonomic groups is used for screening-level risk assessments. 

2 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 3 Freshwater fish represent surrogates for aquatic-phase amphibians. 4 Aquatic EECs are based on modeling described in Section 3.2.2.1. 5 Four species of two families of monocots - one is corn, six species of at least four dicot families, of which one is soybeans. 6

 Risk to terrestrial invertebrates from penflufen use is not evaluated, rather the potential hazard to honey bees and earthworms (i.e. the available data) 

are qualitatively assessed. 

2.6.6. Integration of Exposure and Effects 

Exposure and toxicity data are integrated in order to evaluate the risks of adverse ecological 

effects on non-target species. For the screening-level risk assessment of penflufen, the 

deterministic risk quotient (RQ) method is used to compare estimated exposure concentrations 

with measured toxicity values. The RQ method involves dividing point estimates of 

environmental concentrations by acute and chronic toxicity values. The resulting unitless RQs 

are then compared to the Agency’s Levels of Concern (LOC) (USEPA, 2004) (Table 2.3). 

These criteria are used to indicate when applications of penflufen, as directed on the proposed 

labels, have the potential to cause adverse effects to listed and non-listed non-target organisms. 
-Page 19 of 115- 

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

Class. 

RISK CLASS RISK DESCRIPTION RQ LOC 

Aquatic Animals (fish and invertebrates)

Acute Potential for effects to non-listed animals from acute 

exposures 

Peak EEC/LC501 0.5 

Acute 

Restricted Use 

Potential for effects to animals from acute exposures 

Risks may be mitigated through restricted use classification Peak EEC/LC501 0.1 

Acute Listed 

Species 

Listed species may be potentially affected by acute 

exposures 

Peak EEC/LC501 0.05 

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

chronic exposures 

60-day EEC/NOAEC 

(fish) 1 

21-day EEC/NOAEC 

(invertebrates) 

Aquatic Plants 

Non-Listed Potential for effects to non-listed plants from exposures Peak EEC/LC501 1 

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

Terrestrial Animals (mammals and birds) 

Acute Potential for effects to non-listed animals from acute 

exposures 

EEC2

/LC50 (Dietary) 0.5 

EEC/LD50 (Dose) 

Acute 

Restricted Use 

Potential for effects to animals from acute exposures 

Risks may be mitigated through restricted use classification

EEC2

/LC50 (Dietary) 0.2 

EEC/LD50 (Dose) 

Acute Listed 

Species 

Listed species may be potentially affected by acute 

exposures 

EEC2

/LC50 (Dietary) 0.1 

EEC/LD50 (Dose) 

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

chronic exposures EEC 2

/NOAEC 1 

Terrestrial and Semi-Aquatic Plants 

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

exposures 

EEC/ EC25 1 

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

exposures 

EEC/ NOAEC 

1 

EEC/ EC05

1 LC50 or EC50. 2

 Based on upper bound seeding rates.

3. Analysis 

3.1. Use Characterization 

Penflufen is proposed primarily for use as a seed treatment. Proposed maximum application 

rates and use patterns listed by use according to the proposed labels are provided in a mass per 

unit area basis in Table 3.1. The in-furrow application, used with seed piece treatment only (e.g.

potatoes) is immediately incorporated to a depth of 3-6 inches, per the proposed label and USDA 

Crop Profiles for potato cultivation (USDA, 2000). For the purpose of this screening-level risk 

assessment, the entire per-acre rate for the in-furrow treatment is assumed to be additive to the 

per-acre rate for the seed piece treatment (i.e. 0.14 lbs a.i./A for seed piece and 0.14 lbs a.i./A for 
-Page 20 of 115- 

the in-furrow applications for a total penflufen application rate of 0.28 lbs a.i./A). Given that the 

entire acre would not be treated, this is likely a conservative assumption. Surface applied seed 

(beans and peas, cereal grains, wheat, alfalfa, canola, and other oil seed crops) are broadcast on 

the soil surface. Alfalfa and beans are applied as a “slurry treatment.” The slurry treatment 

principle involves suspension of wettable powder treatment material in water. The treatment 

material applied as a slurry is metered through a sample mechanism composed of a slurry cup 

and seed dump pan. The cup introduces a given mass of slurry with each dump of seed into a 

mixing chamber where seed are blended. The seeds are then moved into a hopper for application 

to the field surface..

Table 3.1. Proposed Maximum Use Patterns of Penflufen. 

Crop/Use Formulated Product 

Maximum 

Application 

Rate 

(lbs a.i./A)*

Maximum 

Number of 

Applications 

(interval) 

Maximum 

Yearly 

Application 

(lbs a.i./A/yr) 

Method of 

Application 

Potato other tuberous 

corm vegetables 

 (in-furrow app with 

seed pieces) 

PEN 240 FS 0.14 NS NS 

Ground infurrow (with 

seed piece 

application) 

Potato seed pieces PENCLO, PEN 240FS 0.14 NS NS Treated seed 

pieces 

Beans (slurry) PENTRI 308 FS 0.0384 NS NS Treated seed 

Cereal grains PENRED, PEN 240FS, 0.0078 NS NS Treated seed 

Wheat PENTRI 308FS, 

PENPRO 118FS 0.0078 NS NS Treated seed 

Rice PENRED, PEN 240FS, 

PENPROME 177FS 0.00645 NS NS Treated seed 

Corn PENRED, PEN 240FS 0.0033 NS NS Treated seed 

Alfalfa (slurry) PENRED, PEN 240FS, 

PENTRI 308FS 0.00225 NS NS Treated seed 

Cotton 

PENRED, PENCLO, 

PEN 240FS, PENTRI 

308FS 

0.0019 NS NS Treated seed 

Canola and other 

oilseed crops 

PENRED, PEN 240FS, 

PENCLOTRIME 0.00123 NS NS Treated seed 

*USEPA, 2011a, Acres Planted per Day and Seeding Rates of Crops Grown in the United States, Memorandum from Beck and Ratnayake,

Biological and Economic Analysis Division, to Deschamp (HED) and Spatz (EFED), March 2011. 

3.2. Exposure Characterization 

3.2.1. Environmental Fate and Transport Characterization 

The general physical/chemical properties of penflufen are summarized in Table 3.2. 

Environmental fate and transport properties of penflufen are characterized in further detail in the 

following sections. The Agency’s understanding of these properties is limited by the available 

dataset. Many of the chemical properties and environmental fate parameters of penflufen listed in 

Table 3.3 are based on studies classified as supplemental. Additional detail on each study is 

provided in Appendix D. 

Based on the chemical structure of the compound, the compound has a stereocenter and may 
-Page 21 of 115- 

show enantiomeric selection in the degradation studies. This was not addressed in the 

degradation studies submitted to the Agency. Additional data on this issue to address 

enantiomeric selection would reduce the uncertainty of the degradation of penflufen isomers. 

Table 3.2 General Physical and Chemical Properties of Penflufen 

Parameter Value Reference

PC code 100249 -- 

CAS No. 494793-67-8 -- 

Structure 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

-- 

Chemical name 

(IUPAC) 

(RS)-N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1Hpyrazole-4-carboxamide

-- 

Chemical name (CAS) 1H-Pyrazole-4-carboxamide, N-[2-(1,3-dimethylbutyl)phenyl]-5-

fluoro-1,3-dimethyl- 

-- 

Common name Penflufen (BYF14182) -- 

Chemical formula C18 H24 F N3 O -- 

Molecular weight 317.41 g/mol 48023535 

Water solubility (20oC, 

pH 7)

10.9 mg/L 48023535 

Vapor pressure (25oC) 9.0 x 10-9 torr 48023537 

Henry's law constant 1.04 x 10-10 atm·m3/mol 48023539 

Octanol-water 

partitioning coefficient 

Log KOW (20oC, pH 7) 

3.3 48023534 

Dissociation Constant 

(pKa) 

No dissociation constant was found in aqueous solution of 

penflufen in the range of 1 < pH < 12. The molecule has 

no structural moieties which are prone to dissociate. 

48023532 

Penflufen is persistent in aerobic and anaerobic conditions, and is moderately mobile based on 

the FAO soil mobility classifications (mean Koc = 365; MRID 48023546) (USEPA, 2006a). 

The compound is nonvolatile, lipophilic, and does not bioconcentrate in aquatic organisms. 

Penflufen is persistent in soil with half-lives ranging from 115 to 433 days in aerobic soil from 

two studies conducted in six soils (MRID 48023552, 48023553). The compound degrades very 

slowly in anaerobic soil, with an extrapolated half-life of 886 days (MRID 48023555). There is 

no evidence of degradation via hydrolysis, which was studied across environmental pHs (pH 5, 

7, and 9 at 50oC; MRID 48023547). Penflufen also degrades slowly by aerobic aquatic 

metabolism, with half-lives ranging from 267 to 301 days (MRID 48023556). There is no 

evidence of degradation in anaerobic aquatic systems (MRID 48023557). A potentially major 

route of degradation may be aqueous photolysis (environmental half-life of 83 days; MRID 

48023548); however photolysis is slow and only likely to play a significant role in shallow, clear 
-Page 22 of 115- 

waters. A summary of the submitted environmental fate and transport data is summarized below 

in Table 3.3. 

Penflufen is expected to persist in both terrestrial and aquatic environments. The degradate Pen3HB is much more mobile than the parent, but the AAP degradate is comparatively immobile. 

Under aerobic conditions, AAP can be slowly metabolized, but it is stable to anaerobic 

metabolism. AAP persists, with half-lives ranging from 116-260 days (there are no metabolism 

data for Pen-3HB). Penflufen was detected in submitted terrestrial field dissipation studies above 

the level of quantitation (LOQ) at depths up to 60 cm, however the majority of reported 

detections were from the upper soil layers (0-15 cm). 

Table 3.3 Environmental Fate Data Summary for Penflufen 

OPPTS 

Guideline 

Data Requirement Data Summary Source 

835.2120 Hydrolysis t1/2 at 50°C Stable MRID 48023547 

835.2240 Aqueous photolysis t1/2 at 25°C 83 days (36 days in river water) MRID 48023548 

(MRID 48023549) 

835.2410 Soil photolysis t1/2 at 22°C No data (soil incorporated/seed treatment use) -- 

835.4100 Aerobic soil metabolism t1/2 at 25°C 249 days (silt loam) 

433 days (sandy loam)* 

MRID 48023553 

Aerobic soil metabolism t1/2 at 20oC 117 days (silt loam) 

165 days (sandy loam)* 

243 days (loam)* 

129 (loam)* 

MRID 48023552, 

AAP (degradate)

257 days (sandy loam)* 

116 days (silt loam) 

231 days (loam)* 

128 days (clay loam)* 

MRID 48023554 

835.4200 Anaerobic Soil Metabolism t1⁄2 at 20°C 866 days* MRID 48023555 

835.4300 Aerobic aquatic metabolism t1/2 at 20°C 

(sandy loam:sediment system) 

301 days* MRID 48023556 

835.4400 Anaerobic aquatic metabolism t1/2 at 20°C 

(combined labels) 

Stable MRID 48023557 

835.1230 Organic carbon partitioning coefficient 

(Koc, mL/g oc) 

404 (sandy loam) 

283 (silt loam) 

257 (loam) 

475 (Goldsboro loamy sand) 

407 (Oska-Martin clay loam) 

MRID 48023546 

pen-3HB 

(transformation product)

30 (sandy loam) 

40 (silt loam) 

 37 (sandy loam) 

63 (Goldsboro sandy loam) 

69 (Oska-Martin clay loam) 

AAP 

(transformation product)

1954 (sandy loam) 

1868 (silt loam) 

1906 (silt loam) 

3553 (Goldsboro sandy loam) 

MRID 48023544 

MRID 48023545 
-Page 23 of 115- 

OPPTS 

Guideline 

Data Requirement Data Summary Source 

9313 (Oska-Martin silty clay) 

Freundlich adsorption value, Kf , mL/g oc 

(1/n) 

4.9 (0.89), sandy loam 

4.7 (0.89), silt loam 

2.6 (0.94), loam 

5.4 (0.95), Goldsboro loamy sand 

6.0 (0.86), Oska-Martin clay loam 

MRID 48023546 

pen-3HB (transformation product)

0.62 (0.95), sandy loam 

0.98 (0.95), silt loam 

0.63 (0.96), sandy loam 

0.44 (0.91), Goldsboro sandy loam 

1.36 (0.98), Oska-Martin clay loam 

AAP (transformation product) 

14.9 (0.76), sandy loam 

24.4 (0.77), silt loam 

18.7 (0.79), silt loam 

10.9 (0.69), Goldsboro sandy loam 

127.7 (0.89), Oska-Martin silty clay 

MRID 48023544 

MRID 48023545 

835.6100 Terrestrial field dissipation DT50 

US soils 

11 days (Tifton loamy sand, GA) 

340 days (Delco loam, ID) 

MRID 48023559 

MRID 48023560 

Terrestrial field dissipation DT50 

Canadian soils 

14 days (Harriston loam, ON) 

202 days (Weyburn sandy loam, SK) 

15 days (Alberry sandy loam, PE) 

MRID 48023561 

MRID 48023562 

MRID 48023563 

Terrestrial field dissipation DT50 

European soils 

187 days (clay loam, France) 

100 days (clay, UK) 

133 days (sandy loam/sandy clay loam, 

Sweden) 

193 days (loam, Germany) 

77 days (loam, Italy) 

53 days (loam/sandy clay loam, Spain) 

MRID 48023564 

850.1730 Fish bioconcentration (BCF) 

(steady state BCF ) 

Edible, viscera, whole 

Low dose (0.45 ug/L): 35, 186, 100 

High does (4.5 ug/L): 37, 187, 103 

MRID 48023589 

*Indicates the half-life was extrapolated beyond the termination of the study. 

3.2.1.1. Transport and Mobility 

Penflufen is not volatile, with a partial vapor pressure of 9.0 x 10-9 torr at 25oC (MRID 

48023537). The molecule has no structural moieties that are prone to dissociate. The reported 

Kow for penflufen at 25oC for pH 7 was 1,995 (LogKow = 3.3; MRID 48023534). 

Penflufen is moderately mobile to mobile based on FAO Soil Mobility Classification Guidance 

(USEPA, 2006a), with reported organic carbon partitioning coefficients ranging from 257 to 475 

(Freundlich adsorption constants (Kf) from five soils ranging from 2.6 to 6.0; corresponding 

adsorption isotherms 0.86 to 0.95) (MRID 48023546). Batch equilibrium data for penflufen 

show that adsorption to soil is not well correlated with organic carbon content (r2

 = 0.578, p = 

0.14), pH (r2

 = 0.272, p = 0.37), clay content (r2 = 0.183, p = 0.47), or CEC (r2 = 0.487, p = 

0.19). However, the coefficient of variation for Koc values (25%) is less than that for Kf values 

(27%); therefore, the mobility of penflufen in soil may be partially affected by the soil fraction of 

organic carbon. 
-Page 24 of 115- 

 

Leaching and adsorption/desorption studies were conducted on the two major degradates1

: pen3HB and AAP. Pen-3HB is much more mobile than the parent, however AAP reported high 

sorption values compared to the parent indicating that it has a higher binding affinity (correlated 

with % clay content) (MRID 48023544, 48023545). 

3.2.1.2. Degradation 

Penflufen is stable to hydrolysis; there was no evidence of degradation at pH 4, 7, and 9 at 50oC 

(MRID 48023547). It is slowly photolabile in clear water (environmental half-life of 83 days at 

pH 7; MRID 48023548). In the presence of natural compounds found in river water, penflufen 

may more quickly photolyze in water (environmental half-life of 36 days). 

Penflufen biodegrades slowly in aerobic soil, with reported half-lives ranging from 117 to 433 

days (parent-only half-lives; MRID 48023552, 48023553). Un-extracted residues were 

substantial (as high as 26%) in all aerobic metabolism studies. Multiple solvent systems were 

not employed in the extraction scheme, and it is uncertain to what extent unextracted residues 

consist of bound or available parent compound or degradates. Supplemental data characterizing 

the extraction of parent residues from sterile and non-sterile soils was submitted by the registrant 

following the Agency’s review of the metabolism studies. The study was submitted November 

8, 2011 and was assigned MRID 48652501. The results from the comparison between 

extractions from sterile (gamma-irradiated) and non-sterile (viable) soils showed that a portion of 

the unextracted residues reported in the metabolism half-lives are biologically mediated and 

potentially irreversibly bound. Therefore, for risk assessment exposure estimates were based on 

half-lives calculated for the parent-only. 

Results from the two aerobic soil metabolism studies on six different soil types show penflufen 

degrades via hydroxylation at the alkyl side chain in the 3-position to form pen-3HB, which 

further oxidizes to AAP and multiple unidentified minor compounds. Apparently irreversible 

sorption of unextracted residue is substantial, and in general formation of CO2 is minimal. 

Figure 3.1 illustrates a predicted degradation pathway under aerobic conditions. 

1

 A major degradate is defined as a compound that is detected in the fate studies at > 10% of the applied radiation. 
-Page 25 of 115- 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

OH

N N H

N

O

F O

3CH

3CH

3CH

BYF 14182-3-hydroxy-butyl

BYF 14182-pyrazolyl-AAP

(AE 2300037)

Penflufen

BYF 14182

Non-extractable residues + CO2

Figure 3.1 Predicted Transformation Pathway under Aerobic Conditions 

An aerobic aquatic metabolism study was conducted for penflufen investigating the 

biotransformation of penflufen in two water-sediment systems from Germany: a sand-gravel pit 

lake water system (Angler Weiher), and a loam-pond water system (Hoenniger Weiher). 

However, due to unexplained variability in the material recovery from the Angler system, only 

calculated half-lives from the Hoenniger system are acceptable for risk assessment. The rate of 

biodegradation of penflufen was slower in aquatic environments than terrestrial environments 

(parent-only single first-order half-life of 301 days (DT90 of 942 days) in the water-sandy loam 

sediment system; MRID 48023556; parent plus unextracted residues, single first-order half-lives 

of 978 days). The compound dissipated from the water column comparatively quickly (water 

dissipation half-life of 5.9 days), and was detected in the sediment. In anaerobic aquatic 

environments, penflufen is apparently stable to biodegradation; there was no evidence of 

degradation (MRID 48023558). 
-Page 26 of 115- 

3.2.1.3. Field Studies 

Seven terrestrial field dissipation studies were conducted for penflufen at three sites in the United 

States (Georgia, Idaho, and California), three sites in Canada (Ontario, Saskatchewan, and Prince 

Edward Island), and six sites in the European Union (France, UK, Sweden, Germany, Italy, and 

Spain). It is important to note that the California field dissipation study was found unacceptable 

because the dissipation route(s) were not well characterized. All North American studies were 

conducted with broadcast applications to bare ground (MRID 48023569, 48023560, 48023561, 

48023562, 48023563), each site included four bare ground plots that had <1% slope (except 

Georgia, where the slope was 2.8%) and no runoff collection equipment. Penflufen was applied 

at an exaggerated broadcast rate in all of the North American field studies; up to 171% of the 

proposed maximum application rate. The method of application in these studies was inconsistent 

with the proposed uses (i.e., proposed uses are seed treatment uses, with one in-furrow spray, not 

surface/foliar applied ground sprays as were used in the field studies). These factors increase the 

uncertainty of the reported dissipation rates in the submitted field studies compared to the 

proposed uses of penflufen (i.e., the rate of dissipation from broadcast applications may be 

greater than for seed treatment and in-furrow application methods, where less material is 

available for runoff and photolysis). Additional data describing the dissipation patterns from use 

patterns similar to the proposed uses (seed treatments) are needed to decrease the uncertainty 

surrounding the dissipation routes for penflufen and its degradates. 

Penflufen residues were primarily detected in the top 0-30cm soil layers. The parent compound 

was detected as deep as 60cm, but was often reported below the limit of quantification. Pen-3HB 

and AAP were only detected in the 0-15cm soil layers. Dissipation rates (DT50) for penflufen 

from the North American field studies ranged from 11-340 days. This wide range encompasses 

the variability observed in the laboratory studies (half-lives ranging from 116-257 days), 

however, the laboratory studies only measure biodegradation, whereas the field studies measure 

dissipation due to transport loss pathways as well (e.g., runoff, leaching, etc.). 

An additional study of six sites in Europe (France, Italy, Spain, Sweden, Germany, and the UK) 

was conducted to study the dissipation in European soils (MRID 48023564). Penflufen was 

broadcast applied to bare soil at an exaggerated rate (0.223 lbs a.i./A), incorporated to an 

unknown depth, and grass was sown into soil following application. Dissipation half-lives from 

the European studies ranged from 52 to 193 days, comparable to the North American field 

studies that reported a similar range of dissipation times. 

There was significant carryover of penflufen residues on an annual basis in the North American 

studies; carryover ranged from 18% (Georgia) to 39% (Idaho), with an average of 29%. 

Dissipation rates (DT50) from Prince Edwards Island, Ontario, and Georgia were <15 days, 

however Saskatchewan and Idaho reported DT50s >200 days. Carryover percentages were 

approaching 40% for Saskatchewan and Idaho compared to Ontario and Georgia which reported 

carryover percentages closer to 20%. 
-Page 27 of 115- 

3.2.1.4. Bioconcentration 

A flow-through bioconcentration study of bluegill sunfish (Lepomis macrochirus) exposed to 

penflufen in pH 7.5-8.0 water for 28 days indicates that bioconcentration of the compound in fish 

does not exceed levels of concern. The 28-day exposure period was followed by a 14 day 

depuration period. Bioconcentration factors (BCF) were 35, 186, and 100x for whole fish, 

edible, and non-edible fish tissues, respectively, in low-dose samples (0.45 μg/L), and 37, 187, 

and 103 for whole fish, edible, and non-edible fish tissues, respectively, in high-dose samples 

(4.5 μg/L) (98% of mean total residues were depurated after 14-days). BCF values less than 1000 

do not trigger criteria for further evaluation of bioaccumulative compounds. 

3.2.1.5. Environmental Degradates 

The major degradates resulting from environmental degradation processes are pen-3HB and 

AAP (Table 3.4). These transformation products were identified in the environmental fate 

studies at concentrations >10% of the applied radioactivity (all major and minor degradates are 

listed in Appendix A, identifying the study in which it was reported). In all six soils studied 

(four German soils, two US soils) pen-3HB was reported at increasing concentrations at the 

study termination (120 days for German soils, 365 days for US soils; 9-18% of the applied). 

AAP was reported in the two U.S. soils, however it was only reported as a major degradate in the 

sandy loam soil. In this study AAP was detected at 61 days after treatment (DAT) and increased 

in concentration through the termination of the study (365 DAT). In the silt loam soil, AAP was 

only detected in the final sampling time period (365 DAT). This suggests that the AAP degradate 

may form after a considerable amount of time has passed (i.e., the study duration for the German 

soils may have been insufficient to capture the formation of AAP). Pen-3HB was also detected as 

a major degradate in the aerobic aquatic metabolism study (13% of the applied radiation), and 

was still increasing in concentration at the termination of the study. Pen-3HB and AAP were also 

both detected in the terrestrial field dissipation studies; however detections were largely 

restricted to the 0-15 cm range of the soil profile. Pen-3HB was detected in the aquatic field 

dissipation study as well. 

Other major degradates detected in the environmental fate studies include BYF 14182-fluoro 

acid (detected in the aqueous photolysis study using river water), and carbon dioxide (both were 

up to 9.9%AR at study termination). 

The environmental degradates of penflufen that are considered to be of exposure concern are 

pen-3HB and AAP. These degradates were formed at increasing concentrations through the 

termination of the environmental fate studies in which they were formed. Therefore, there is 

uncertainty about the formation and decline of these major degradates in the environment. BYF 

14182 fluoro acid may also be a degradate of exposure concern (9.9% of the AR). Due to the 

proposed label methods (primarily as a seed treatment) and because this degradate was only 

detected in the aqueous photolysis study, environmental exposure to this degradate is more likely 

where penflufen is applied to rice paddies, or is transported to shallow, clear water bodies via 

runoff. 
-Page 28 of 115- 

Batch equilibrium data for pen-3HB and AAP show that pen-3HB will be much more mobile 

than the parent (highly mobile based on FAO Standardized Soil Mobility Classifications), and 

that AAP will be much less mobile (hardly mobile based on FAO classifications) (USEPA, 

2006a). Aerobic soil metabolism data from studies using AAP as the starting material show that 

the transformation product will persist under aerobic conditions after it is formed (half-lives 

ranged from 115 to 231 days in three soils; MRID 48023554). 

Minor degradation products may be of exposure concern; however their structures were not 

reported in any study, and their percent of formation was frequently below 2%, except for BYF 

14182-pyrazole-4-carboxamide which was detected at nearly 7% in a submitted aqueous 

photolysis study (MRID 48023548; Appendix A). 

Two degradates were detected in plant tissue (rice plants) in the aquatic field dissipation study; 

pen-3HB and penflufen-bis-desmethyl-3-carboxylic acid. Pen-3HB was detected in other fate 

studies (aerobic soil and aerobic aquatic metabolism, as well as anaerobic soil metabolism); 

however penflufen-bis-desmethyl-3-carboxylic acid was only detected in the plant tissue. 

Table 3.4. Table of Transformation Products Formed in Environmental Fate Studies 

Common Name Chemical Name 

Study in Which Found 

(Maximum % of Parent, or equivalent) 

Reference 

MRID 

Pen-3HB 

(penflufen-3-

hydroxy-butyl; 

M01) 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

OH

5-fluoro-N-[2-(3-hydroxy-1,3-

dimethylbutyl)phenyl]-1,3-

dimethyl-1H-pyrazole-4-

carboxamide 

Aerobic soil metabolism (17.5%) 

Aerobic aquatic metabolism (13.3%) 

Anaerobic soil metabolism (7.1%) 

Terrestrial field dissipation (9.0 ng/g) 

Aquatic field dissipation (0.7 ng/g) 

48023553 

48023556 

48023555 

48023564 

48023565 

AAP (penflufenpyrazolyl-AAP; 

M02) 

N N H

N

O

F O

3CH

3CH

3CH

N-(2-acetylphenyl)-5-fluoro-1,3-

dimethyl-1H-pyrazole-4-

carboxamide 

Aerobic soil metabolism (13.4%) 

Terrestrial field dissipation (1.6 ng/g) 

48023553 

48023564 

Penflufen-fluoro 

acid (M60) 

OH N

N

O

F

3CH

3CH

5-fluoro-1,3-dimethyl-1H-pyrazole4-carboxylic acid Aqueous photolysis, river water (9.9%) 48023549 

Carbon dioxide Carbon dioxide -- -- 

Degradates of penflufen found in plant tissue during Aquatic Field Dissipation study 
-Page 29 of 115- 

Pen-3HB 

(penflufen-3-

hydroxy-butyl; 

M01) 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

OH

5-fluoro-N-[2-(3-hydroxy-1,3-

dimethylbutyl)phenyl]-1,3-

dimethyl-1H-pyrazole-4-

carboxamide 

Aquatic field dissipation, rice tissue (11.5 

ng/g) 48023565 

BYF 14182-bisdesmethyl-3-

carboxylic acid 

(M64) 

N

N

H F

O OH

5-fluoro-1H-pyrazole-3-carboxylic 

acid

Aquatic field dissipation, rice tissue (6.1 

ng/g) 48023565 

3.2.2. Measures of Aquatic Exposure 

3.2.2.1. Surface Water Exposure 

The Tier II model Pesticide Root Zone Model (PRZM v3.12.2; May 12, 2005; Carousel et al., 

undated) linked with EXposure Analysis Modeling System (EXAMS v2.98.4.6; Apr. 25, 2005; 

Burns, 2004) via the PRZM/EXAMS model shell (PE v5.0, Nov. 15, 2006), i.e., 

PRZM/EXAMS) and the Tier I Rice Model (v1.0, May 8, 2007) were used to estimate screeninglevel exposure concentrations in aquatic environments. The PRZM model simulates pesticide 

movement and transformation on and across the agricultural field resulting from crop 

applications. The EXAMS model simulates pesticide concentrations in water due to 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 for multiple (usually 30) years, from 

which the Agency estimates peak values that are expected to recur on average once every ten 

years, based on time series of daily estimated concentrations. The coupled PRZM and EXAMS 

models and user’s manuals are available from the U.S. Environmental Protection Agency Water 

Models web-page (USEPA, 2011b). 

Exposure estimates generated using the standard pond are intended as surrogates for potential 

concentrations in a wide variety of vulnerable water bodies, including prairie potholes, playa 

lakes, vernal pools, other wetlands, man-made and natural ponds, and ephemeral and first-order 

streams. Innumerable site-specific factors will tend to make such water bodies more or less 

vulnerable than the standard pond. Static water bodies that have larger ratios of pesticide-treated 

drainage area to water body volume are generally expected to have higher peak concentrations 

than the standard pond’s EECs. Such water bodies may be smaller in size, and/or have larger 

drainage areas. However such water bodies may be more likely to overflow and discharge 

pesticide in their effluent, whereas the standard pond has no discharge. As watershed size 

increases, it becomes increasingly unlikely that the entire watershed is planted with a single crop 

that is all treated simultaneously with a pesticide. Headwater streams may have peak 

concentrations that are higher than those predicted for the standard pond, but such concentrations 
-Page 30 of 115- 

will likely persist for only short periods of time or distance, as they are carried downstream and 

diluted with water originating elsewhere. 

The Tier I Rice Model was used to estimate screening-level exposure to penflufen that may 

occur in water bodies receiving released water from rice paddies that were seeded with rice seed 

treated with penflufen. This model was used to assess the proposed use on rice seed because the 

PRZM/EXAMS exposure models do not specifically address the unique rice growing 

environment and the model is approved for use in risk assessment. The model produces a single 

exposure value that represents a dissolved concentration within a rice paddy. This single value is 

used to approximate both acute and chronic exposures. 

The Tier I Rice Model relies on an equilibrium partitioning concept to provide conservative 

exposure estimates resulting from application of pesticides to rice paddies. When a pesticide is 

applied to a rice paddy, the model assumes instantaneous partitioning between the water and 

sediment phases. The model does not account for pesticide degradation, mass transfer between 

the aqueous phase and the sediment, volatilization, dilution, or other potentially important 

attenuation processes; therefore the model provides an upper-bound estimate of exposure for 

penflufen which is proposed for use on rice as a dry-seeded application (seed treatment). The 

Tier I Rice Model was calibrated to generate estimates that are consistent with or conservative 

for dissolved concentrations measured within rice paddies and in discharged paddy water. The 

model was not evaluated or calibrated for concentrations measured in sediment and does not 

account for residues bound to suspended sediment. A description of and guidance for using the 

Tier I Rice Model may be found on the U.S. Environmental Protection Agency (EPA) Water 

Models web-page (USEPA, 2011b). 

The general chemical and environmental fate data for penflufen listed in Table 3.2-3.3 were used 

for generating model input parameters for PRZM and EXAMS (listed in Table 3.5). Chemical 

specific and model input values were chosen in accordance with current divisional guidance 

(USEPA, 2009). 

 
-Page 31 of 115- 

Table 3.5. PRZM and EXAMS Surface Water Chemical Input Parameters for Penflufen. 

Input Parameter Value Comment Source 

Molecular Mass (g·mol-1) 317.41 Product chemistry 48023535 

Vapor Pressure at 25°C 

(torr) 9.0 x 10-9 Product chemistry 48023535 

Solubility in Water at 

20oC, pH7 (mg·L-1) 10.9 Product chemistry 48023537 

Organic carbon partition 

coefficient (Koc, mL/g oc) 290 Parent only (mean of 5 soils) 

48023546 

48023544 

48023545 

Aerobic Soil Metabolism 

Half-life (days) 293.3 Parent only half-life (upper 90th

percentile on the mean of 6 soils) 

48023552 

48023553 

Aerobic Aquatic 

Metabolism Half-life 

(days) 

639

Parent only half-life from one 

water:sediment system. Adjusted 

to 25oC using a Q10 of 2 

(measured T1⁄2 is 301 days from 

one water:sed system). Value is 

multiplied by 3 to account for 

potential variability in different 

water:sediment systems. 

48023556 

Anaerobic Aquatic 

Metabolism Half-life 

(days) 

Stable No evidence of degradation. 

48023557 

Hydrolysis Half-lives 

(days) Stable No evidence of degradation at 50oC, pH 4, 7, 9. 

48023547 

Aqueous Photolysis 

Half-life (days) 83 Corrected environmental half-life 48023548 

The model input parameters used in PRZM to simulate penflufen application and management 

practices are provided in Table 3.6. The initial application date was selected in order to reflect 

when the crop is planted, since the penflufen applications are for seed treatments or for a single 

in-furrow spray at planting for potato and other tuberous corm vegetables. Timing of planting 

was determined by consulting the crop-profile information provided by the United States 

Department of Agriculture (USDA, 2000). The modeled bean/legume use represents the realm 

of penflufen seed treatments for crops that are seeded at the surface, and the modeled potato use 

represents crops that are seeded below the surface. The potato and bean uses were selected for 

aquatic modeling purposes because they have the highest proposed application rates, and are two 

different application methods of penflufen as a seed treatment (potato seed piece treatment plus 

an in-furrow spray, and a “slurry type” seed treatment application method). These model runs 

are used as upper-bound estimates of exposure and represent the exposure from other uses of 

penflufen that are permitted at lower rates (for use as a seed treatment fungicide on vegetable, 

turberous and corm, alfalfa, grains, cereal, rice, vegetables, legume, including soybeans, canola, 

borage, crambe, cuphea, echium, flax seed, gold of pleasure, hare’s ear mustard, lesquerella, 
-Page 32 of 115- 

lunaria, meadowfoam, milkweed, mustard seed, oil radish, poppy seed, rapeseed, sesame, sweet 

rocket, calendula, castor oil plant, Chinese tallowtree, euphorbia, evening primrose, jojoba, niger 

seed, rose hip, safflower, stokes aster, sunflower, tallowwood, tea oil plant, veronia, cottonseed). 

Application rates for modeling purposes were selected in accordance with the proposed labels to 

generate the most conservative estimates of aquatic exposure. 

Table 3.6 PRZM/EXAMS Model Input Parameters for Penflufen Application Methods 

Use Scenario 

Application 

Rate lbs a.i./A 

(kg a.i./ha) 

Applications 

per Year 

Application 

Interval 

(days) 

Date of 

Initial 

Application

Application 

Method 

(CAM) 

Potato1

IDNpotato_WirrgST

D.txt 

0.28 

(0.31) 1 NA May 1 

Granular 

incorporated, 

3 inches3 

(4) 

MEPotatoSTD.txt 0.28 

(0.31) 1 NA May 1 

Granular 

incorporated, 

3 inches3 

(4) 

Beans and peas 

including including 

soybean2

MSsoybeanSTD.txt 0.04 1 NA March 16 

Granular 

broadcast 

(2)4 

NA = not applicable 

1

 Includes a seed piece application at 0.14 lb a.i./A, and an in-furrow application that occurs at planting for potato and other tuberous and corm 

vegetables at a rate of 0.14 lb a.i./A for a total single maximum application of 0.28 lb a.i./A. 2

 Beans and Legumes include a “slurry type” seed treatment that involves suspension of wettable powder treatment material in water. The 

treatment material applied as a slurry is accurately metered through a sample mechanism composed of a slurry cup and seed dump pan. 3

 Potatoes are planted at depths ranging from 3 – 6”. 3” was selected as the conservative end of this range (USDA, 2000). Application was modeled 

as a granular application due to the seed piece treatment. 

4

 Modeled as a granular, broadcast, unincorporated application per DRAFT guidance for Recommended Input Parameter for Simulating Various 

Pesticide Application Practices, R. David Jones, through the WQTT. Provisional Guidance. 

Two scenarios were used to represent the potato use because they represent different potato 

producing regions of the country. The field used to represent Idaho potato production is located 

in Bingham County, Idaho. This is an approved standard PRZM scenario for potatoes 

(IDNpotato_WirrgSTD.txt). According to the 2000 Census of Agriculture, Idaho is the leading 

potato producing state in the United States, producing greater than 29% of the total U.S. crop. 

The field has Malm fine sandy loam soil, which has a volcanic origin ideal for growing potatoes. 

This is a hydrologic soil group C soil. The weather data are from weather station W24156, 

Pocatello, Idaho. The field used to represent potato production in Maine is located in Aroostook 

County (#1 producing county in Maine) in Northeastern Maine (MLRA143/146). This is also an 

approved standard PRZM scenario for potatoes (MEPotatoSTD.txt). Aroostook County 

produces approximately 90 percent of Maine’s potatoes. According to the 1997 Census of 

Agriculture, Maine is the 3rd largest producer of potatoes in the United States behind Idaho and 

Pennsylvania. The soil selected to simulate the field is a Conant silt loam. Conant silt loam is a 

fine loamy, isotic, frigid Aquic Haplorthods. These soils are extensively used for potatoes, oats 

and peas. This is a hydrologic soil group C soil. The weather data are from weather station 

W14607, Caribou, ME. 

The field used to represent beans and peas (including soybean) is in Yazoo County, Mississippi. 

This is one of the approved standard PRZM scenarios used for modeling legumes 

(MSsoybeanSTD.txt). The field has Loring silt loam soil, which is a fine-silty, mixed, active, 
-Page 33 of 115- 

thermic Oxyaquic Fragiudalfs. This is a hydrologic soil group C soil. The weather data are from 

weather station W03940, Jackson, Mississippi. 

The Tier I Rice Model was used to estimate screening-level exposure to penflufen that may 

occur in water bodies receiving released water from rice paddies that were seeded with rice seed 

treated with penflufen. This model uses the application rate for rice (0.006 lb a.i./A) and the 

organic carbon partitioning coefficient for penflufen (290 mL/g oc). 

The modeled aquatic EECs resulting from the proposed penflufen uses (listed in Table 3.7) were 

used for risk estimation in this screening-level assessment. The model input and output 

filenames supporting these values are listed in Appendix E. 

Table 3.7. Modeled Aquatic Surface Water 1-in-10-year EECs for Proposed Uses of 

Penflufen1

Uses Scenario Max. App. rate

(lbs a.i./A/yr) Peak (ppb) 21-day (ppb) 60-day (ppb) 

Potato MEpotato 0.28 3.52 3.50 3.47 

IDpotato 0.28 1.13 1.10 1.07 

Beans and Peas MSsoybean 0.04 2.39 2.36 2.32 

Rice Tier I Rice Model 0.006 4.71 <4.71 <4.71 1

 Range in model estimates represent the upper bound of estimated environmental concentrations completed using half-lives for parent-only. 

The ecological pond modeled with EXAMS is a static water body of fixed volume and no outlet 

(i.e. no flow-through). Penflufen is persistent in aquatic environments and since the ecological 

pond has no outlet to discharge chemical, the modeling indicates penflufen accumulates in the 

pond throughout the 30-year simulations. Exposure endpoints, in this assessment, are based on 

yearly peak concentrations. In the case of persistent compounds in the farm pond, a 1-in-10 year 

EEC does not only reflect varying meteorological conditions that are expected once every 10 

years, since material carries over from year to year. Thus the yearly peaks are not independent, 

but are partially functions of the previous year’s concentrations. The graph below (Figure 3.2) 

of the daily PRZM/EXAMS EECs from the Maine potato model run shows that because 

penflufen is persistent, there is a buildup of the compound over the entire simulation. It should 

be noted that the peak from the first modeled year of application is estimated to be less than 1.0 

ug/L compared to the reported peak acute value of 3.52 ug/L. This is a result of the buildup from 

year to year due to the persistence of penflufen and the EXAMS farm pond is a static water 

body. Carry-over of residues in the rice paddy over multiple years was not considered. 
-Page 34 of 115- 

Figure 3.2. Daily PRZM/EXAMS Output for Maine Potatoes 

0.00E+00

5.00E‐01

1.00E+00

1.50E+00

2.00E+00

2.50E+00

3.00E+00

3.50E+00

4.00E+00

1/1/19611/1/19631/1/19651/1/19671/1/19691/1/19711/1/19731/1/19751/1/19771/1/19791/1/19811/1/19831/1/19851/1/19871/1/19891/1/1991

Daily Aquatic EEC (ug/L)

Date (mm/dd/yyyy)

Penflufen: Maine Potato Daily Output

3.2.2.2. Sediment Pore Water Exposure 

Environmental fate data show that penflufen dissipates from the water column but not from 

aquatic systems in their entirety, as it has been detected in sediment; therefore sediment exposure 

may be a concern for sediment-dwelling organisms. Benthic sediment pore water EECs were 

calculated for the proposed maximum use patterns for penflufen. Pore-water EECs are provided 

in Table 3.8. The rice model does not estimate pore water concentrations. 

Table 3.8. 1-in-10 year Pore Water EECs for Proposed Uses of Penflufen

Uses Scenario Max. App. rate

(lbs a.i./A/yr) Peak (ppb) 21-day (ppb) 60-day (ppb) 

Potato MEpotato 0.28 3.45 3.44 3.43 

IDpotato 0.28 0.97 0.97 0.97 

Beans and Peas MSsoybean 0.04 2.21 2.20 2.19 
-Page 35 of 115- 

3.2.3. Measures of Terrestrial Exposure 

3.2.3.1. Terrestrial Wildlife 

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

emphasizing a dietary exposure route for uptake of the pesticide active ingredient. Birds are 

considered surrogates for terrestrial-phase amphibians as well as reptiles. For exposure to 

terrestrial organisms from seed treatments, estimation of pesticide residues in or on seeds as food 

items assumes organisms are exposed to a single pesticide residue in a given exposure scenario 

and focuses on the possible dietary ingestion of residues. For seed applications, estimation of 

loadings of penflufen per unit area is calculated based on known or estimated seeding rates. This 

approach, which intends to represent exposures via multiple routes and not just direct ingestion, 

considers observed acute effects (acute oral LD50) in terrestrial toxicology studies and relates 

them to the surface area where the pesticide is applied (LD50/ft2

). 

T-REX is used to calculate dose-based EECs of penflufen for mammals and birds consuming 

treated seeds. Seeding rates as well as maximum penflufen application rates according to the 

proposed label for the major uses of penflufen are provided in Table 3.9. Other seed treatment 

use patterns are an order of magnitude below on a per acre basis. Estimated avian and 

mammalian doses of penflufen as determined using T-REX are also provided in the table. Risk 

quotients (RQs) are calculated using the adjusted LD50 for the smallest weight class of animal 

(20 g for birds and 15 g for mammals). 

Table 3.9. Penflufen application rates and corresponding avian and mammalian doses as 

determined using maximum proposed treatment rates and T-REX. 

Crop 

Penflufen 

application 

rate 

(lbs. a.i./A) 

Maximum 

Seeding 

Rate (lbs 

seed/acre)1

Maximum Seed 

Application 

Rate (mg ai/kg 

seed) 

Avian Dose 

(mg ai/kgbw/day) 

Mammalian 

Dose (mg 

ai/kg-bw/day) 

Available 

AI (mg ai 

/ft2

) 

Bean3 0.02 436 47.27 11.96 10.02 0.22 

Canola 0.00123 15 141.82 35.89 30.05 0.10 

Corn 0.0033 33 94.55 23.93 20.03 0.03 

Cotton 0.0019 19 94.55 23.93 20.03 0.02 

Potato 0.13 6969 19.20 4.86 4.07 1.40 

Potato2 0.28 6969 38.41 9.72 8.14 2.79 

Rice 0.006 129 47.27 11.96 10.02 0.06 

Sunflower 0.00123 4 141.82 34.89 30.05 0.01 

Wheat 0.0078 156 47.27 11.96 10.02 0.08 1

 USEPA, 2011a, Acres Planted per Day and Seeding Rates of Crops Grown in the United States, Memorandum from Beck and Ratnayake,

Biological and Economic Analysis Division, to Deschamp (HED) and Spatz (EFED), March 2011. 2

 Succluent beans have the highest seeding rate, therefore present the greatest exposure 3

 Including the in-furrow treatment 
-Page 36 of 115- 

Penflufen exposures to terrestrial invertebrates are not quantitatively calculated for derivation of 

deterministic RQs. However, risk to this taxon is assessed qualitatively in the Risk Description, 

Section 4.2. 

Additionally, the model SIP v1.0 is used to evaluate whether risk to terrestrial animals is of 

concern for drinking water alone. The model assumes those terrestrial animals are getting 100% 

of their drinking water from the treated field. The model uses the solubility of the compound and 

weight-adjusted toxicity values. Results of the model are discussed in the Risk Description. 

3.2.3.2. Terrestrial Plants 

Exposure of naturally-occurring terrestrial and semi-aquatic (wetland) plant species is typically 

estimated using OPP’s TerrPlant (v1.2.2; USEPA, 2006b) model and is assumed to encompass 

areas outside the immediate use site. The TerrPlant model is used to derive EECs in runoff and 

drift for terrestrial and semi-aquatic plants near areas where penflufen has been applied. Runoff 

exposure is assessed in two scenarios: sheet and channel runoff. In the sheet runoff scenario, the 

treated area generating runoff is assumed to drain into an area with equal size containing 

seedlings, resulting in 1, 2, or 5% of the amount applied being deposited. In the channel runoff 

scenario, a ten-to-one ratio of treatment area to receiving area results in 10, 20, or 50% of the 

amount applied being deposited on soil with emerging or emerged seedlings. Spray drift is also 

a source of pesticide loading to non-target areas. There is an assumption that no spray drift is 

associated with seed treatment. The in-furrow treatment is narrowly sprayed close to the ground 

and spray drift from this application is considered negligible. TerrPlant estimates EECs based on 

application rate, application method, chemical solubility in water, type of runoff and default 

assumptions of drift (which is zero in the case of penflufen). The EECs for terrestrial and semiaquatic plants for a single application of penflufen at the maximum label rate for the two highest 

proposed uses are presented in Table 3.10. 

 

Table 3.10 EECs* for Terrestrial and Semi-Aquatic Plants Near Penflufen Use 

Areas. 

Use and Application 

Single Max. 

Application 

Rate 

(lbs a.i./A) 

EECs (lbs a.i./A) 

Total Loading to 

Semi-Aquatic Areas Dry Areas (Total) 

Potato seed 

piece

Seed treatment 

with 

incorporated infurrow spray 

0.28 0.0028 0.028 

Beans* Seed treatment 0.0384 0.000768 0.00768 

*all other uses are applied at a rate at least an order of magnitude lower than beans and potatoes resulting in much lower EECs. 

3.3. Ecological Effects Characterization 

In screening-level ecological risk assessments, effects characterization describes the types of 

effects a pesticide can have on aquatic and terrestrial organisms. To date, toxicity tests for 
-Page 37 of 115- 

amphibian or reptiles are not required; birds are used as surrogates for reptiles and terrestrialphase amphibians and freshwater fish are used as surrogates for aquatic-phase amphibians. This 

characterization is based on the registrant-submitted toxicity data for birds, mammals, fish, 

invertebrates, and plants for penflufen, two major degradates and a typical formulated product 

(PEN 240FS). No data were available in the public literature for penflufen effects 

characterization (see below). 

In addition to the data submitted in support of registration, the public version of ECOTOX 

(ECOTOXicity) database (USEPA, 2011) was searched for additional toxicity data from the 

open literature. The ECOTOX database is a publicly-available, quality-assured, comprehensive 

tool for locating toxicity data from the open literature and is maintained by EPA Mid-Atlantic 

Ecology Division. More information on ECOTOX can be found at: http://www.epa.gov/ecotox. 

Research papers are thoroughly screened using standard procedures before being accepted into 

ECOTOX thereby ensuring consistent, high quality information. For penflufen and its 

degradates, no studies were identified in ECOTOX as of September 18, 2011. 

Given that penflufen is a new active ingredient with no previous registration in the U.S. or any 

other country, it is assumed that no ecological incidents exist for penflufen. 

3.3.1. Aquatic Toxicity Assessment 

The most sensitive acute and chronic effects measurement endpoints associated with penflufen 

exposure to freshwater and estuarine/marine species are summarized in Table 3.11. All 

acceptable and supplemental studies submitted for the registration of penflufen are described 

below. 

Results of acute toxicity studies in freshwater and estuarine/marine fish indicate that penflufen is 

highly to very highly toxic to fish on an acute exposure basis. Dose-dependent sublethal effects 

observed in fish studies included surfacing, lethargy, erratic swimming, loss of equilibrium, loss 

of vertical orientation, labored respiration, and lying on the bottom. Reduced fish length was 

observed in the F1 generation of the available ELS study. Acute toxicity studies indicate that 

penflufen is moderately toxic to freshwater and estuarine/marine invertebrates on an acute 

exposure basis. Quiescence, pale color and abnormal positioning were reported sublethal effects 

in invertebrates. In some studies the pooled control was used by the primary reviewer (Canada). 

In cases where it was judged to not impact the derived endpoint, the statistics were not 

reassessed by the Agency. 
-Page 38 of 115- 

Table 3.11. Most Sensitive Acute and Chronic Toxicity Data for Aquatic Organisms and 

Plants Exposed to Penflufen Technical 

Exposure 

Scenario Species 

Affected 

Endpoint Toxicity Measurement 

MRID 

(Classification) 

Freshwater Fish 

Acute Common carp 

(Cyprinus carpio) 

Mortality 96-hr LC50 = 90 μg a.i./L 

Slope: N/A 

MRID 48023583 

(Acceptable) 

Chronic Common carp 

(Cyprinus carpio) 

Acute-toChronic 

Ratio 

NOAEC = 18.1 μg a.i./L Acute-to-Chronic 

Ratio based on 

[Fathead minnow; 

116/23.4 = an ACR 

of 4.96; 90/ 4.96 = 

18.1]. 

Freshwater Invertebrates 

Acute Water flea 

(Daphnia spp.) 

Immobility 48 hr EC50 >4660 μg a.i./L1

Slope: N/A 

MRID 48023574 

(Acceptable) 

Chronic Water flea 

(Daphnia spp.) 

Reproduction 

& Growth 

21-day NOAEC = 1530 μg a.i./L MRID 48023587 

(Supplemental) 

Subacute Midge 

(Chironomus 

tentans) 

Mortality 

Growth 

Pore Water Exposure 

10 day NOAEC = 780 μg a.i./L

MRID 47443238 

(Supplemental) 

Estuarine/Marine Fish 

Acute Sheepshead minnow 

(Cyprinodon 

variegatus) 

Mortality 96-hr LC50 = 1150 μg total a.i./L

Slope: N/A 

MRID 48023586 

(Acceptable) 

Chronic No studies available 

Estuarine/Marine Invertebrates 

Acute Eastern oyster 

(Crassostrea 

virginica) 

Shell 

Deposition 

96-hr EC50 = 1300 μg a.i./L

Slope: NA 

MRID 48023578 

(Acceptable) 

Chronic No studies available 

Aquatic Plants 

7-day 

exposure 

Duckweed 

(Lemna gibba) 

None 7-day EC50 >4700 μg a.i./L 

NOAEC = 2400 μg a.i./L 

MRID 48023603 

(Acceptable) 

72-hour 

exposure 

Green algae 

(Pseudokirchneriella 

subcapitata) 

None 96-hr EC50 >5100 μg a.i./L 

NOAEC = 520 μg a.i./L 

MRID 480243604 

(Supplemental) 

3.3.1.1 Toxicity to Freshwater Fish 

Acute Effects 

An acute toxicity study (MRID 48023580; Acceptable) with rainbow trout (Oncorhynchus 

mykiss) is available for penflufen. Fish were exposed under static conditions for 96-hour to 

mean measured concentrations of <0.006 (control and solvent control), 0.066, 0.110, 0.22, 0.51 

and 0.93 mg a.i./L. Sublethal effects were observed in fish in the 0.22, 0.51, and 0.93 mg a.i./L 

treatment groups. Sublethal effects noted in the fish included loss of equilibrium, labored 

respiration, abnormal position at the bottom of the water column or at the surface, and 
-Page 39 of 115- 

quiescence. No sublethal effects were observed in fish in the control, solvent control, 0.066, and 

0.110 mg a.i./L groups. Fish mortality was 10, 100, and 100% in the 0.22, 0.51 and 0.93 mg 

a.i./L groups, respectively. There was no mortality in the controls or in the two lowest test 

concentrations (0.066 and 0.110 mg a.i./L). The 96-hour LC50 for rainbow trout was 0.31 mg 

a.i./L (95% confidence interval 0.22 to 0.51 mg a.i./L). The NOAEC was 0.110 mg a.i./L based 

on mortality and clinical signs of toxicity. Penflufen is classified as highly toxic to rainbow trout 

on an acute exposure basis. 

An acute toxicity study (MRID 48023581; Acceptable) with bluegill sunfish (Lepomis 

macrochirus) is available for penflufen. Fish were exposed to mean measured concentrations of 

<0.006 (control and solvent control), 0.065, 0.129, 0.28, 0.51 and 1.00 mg a.i./L. Sublethal 

effects noted in fish in the 0.51 and 1.00 mg a.i./L treatment groups included loss of equilibrium, 

labored respiration, abnormal position at the bottom of the water column and quiescence. No 

sublethal effects were observed in fish in the control, solvent control, 0.065, 0.129, and 0.28 mg 

a.i./L groups. Fish mortality was 70 and 100% in the 0.51 and 1.00 mg a.i./L groups, 

respectively. There was no mortality in the controls or in the other test groups. The 96-hour 

LC50 for bluegill exposed to penflufen was 0.45 mg a.i./L (95% confidence interval 0.28 to 1.00 

mg a.i./L). The NOAEC was 0.285 mg a.i./L and the LOAEC was 0.51 mg a.i./L based on 

mortality. Penflufen is classified as highly toxic to bluegill sunfish on an acute exposure basis. 

An acute toxicity study (MRID 48023582; Acceptable) with fathead minnow (Pimephales 

promelas) is available for penflufen. Fish were exposed to mean measured concentrations of 

<0.006 (control and solvent control), 0.055, 0.106, 0.22, 0.46 and 0.90 mg a.i./L. Sublethal 

effects were noted in the fish in the 0.106 mg a.i./L group included loss of equilibrium and 

quiescence. No sublethal effects were observed in fish in the control, solvent control, and 0.055 

mg a.i./L groups. Fish mortality was 40, 100, 100, and 100% in treatment groups 0.106, 0.22, 

0.46, and 0.90 mg a.i./L, respectively. There was no mortality in the controls or the 0.055 mg 

a.i./L group. The 96 hour LC50 for fathead minnow was 0.116 mg a.i./L (95% confidence 

interval 0.055 to 0.220 mg a.i./L). The NOAEC was 0.055 mg a.i./L based on mortality and 

clinical signs of toxicity. Penflufen is classified as very highly toxic to fathead minnow on an 

acute exposure basis. 

An acute toxicity study (MRID 48023583; Acceptable) with common carp (Carpinus carpio) is 

available for penflufen. Fish were exposed to mean measured concentrations of <0.006 (control 

and solvent control), 0.061, 0.117, 0.196, 0.475 and 0.751 mg a.i./L. No sublethal effects were 

observed in fish in the control, solvent control and 0.061 mg a.i./L group. Sublethal effects 

including loss of equilibrium or fish lying on side or back, quiescent, inactive or abnormally low 

activity, and labored respiration were observed in fish in the 0.117 mg a.i./L group. No mortality 

was observed in the control, solvent control and 0.061 mg a.i./L group. Mortality after 96-hours 

was 90, 100, 100 and 100% in the 0.117, 0.196, 0.475, and 0.751 mg a.i./L groups, respectively. 

Binomial distribution with untransformed data was used to obtain a 96-hour LC50 of 0.090 mg 

a.i./L and a NOAEC of 0.061 mg a.i./L. Penflufen is classified as very highly toxic to common 

carp on an acute exposure basis. 
-Page 40 of 115- 

Degradates 

An acute toxicity limit study (MRID 48023584; Acceptable) with common carp (Cyprinus 

carpio) is available for the degradate penflufen-3-hydroxy-butyl. Carp were exposed, under 

static conditions, to mean measured test concentration of 36.3 mg a.i./L. No mortalities or 

sublethal effects were observed to common carp (Cyprinus carpio) in either the control or 

treatment groups. The 96h-LC50 was, therefore, greater than 36.3 mg a.i./L (mean measured). 

An acute toxicity limit study (MRID 48023585; Acceptable) with common carp (Cyprinus 

carpio) is available for the degradate penflufen-pyrazolyl-AAP. Carp were exposed, under static 

conditions, to mean measured test concentration of 0.799 mg a.i./L. No mortalities to common 

carp (Cyprinus carpio) were observed in either the control or treatment groups. All fish in the 

test group (0.799 mg a.i./L) displayed slight reduced vigor. Therefore, the 96h-LC50 was greater 

than 0.799 mg a.i./L and the NOAEC was 0.799 mg a.i./L. This 96-h LC50 value for penflufenpyrazolyl-AAP is at least one order of magnitude greater than the LC50 reported for carp (0.09 

mg/L). 

 Formulation 

An acute toxicity study (MRID 48024004; Acceptable) with common carp (Cyprinus carpio) is 

available for a representative formulation of penflufen (240FS; 22.4%). Carp were exposed, 

under static conditions, to mean measured test concentration <0.00511 (control), 0.0134, 0.0281, 

0.0620, 0.166, 0.316, 0.641 and 1.46 mg a.i./L.. At study termination, no mortalities or sublethal effects were observed in the control, 0.0134, 0.0281, and 0.0620 mg a.i./L treatment 

groups. Fish mortality was 100% in the 0.166 mg a.i./L treatment group and higher. Sub-lethal 

effects in the 0.166 mg a.i./L and higher treatment groups included abnormally low activity, 

laboured respiration, fish remaining either on the surface or the bottom of the tank, and loss of 

equilibrium followed by death. The 96h-LC50 was 0.101 mg a.i./L and the NOAEC was 0.062 

mg a.i./L, which is roughly equivalent in toxicity to the TGAI. 

Chronic Effects 

A fish early-life stage study (MRID 48023588; Acceptable) was conducted using the fathead 

minnow (Pimephales promelas). The exposure period was 35-days under flow-through 

conditions. The mean measured concentrations were: control and solvent control (<0.6), 6.21, 

12.2, 23.4, 47.6 and 95.7 μg a.i./L. Hatching started on day 4 and was completed by day 5. 

There was a significant difference in time to hatch between the pooled controls and the 95.7 μg 

a.i./L treatment group on day 4, however, this delay in time to hatch was no longer evident by 

day 5. There was also no statistical difference in larval survival between the pooled controls and 

any of the treatment groups. Both the percent hatched and percent larval survival ranged between 

92 and 97%. The growth parameter of fish length was the most sensitive endpoint in this study 

(3% at NOAEC). The 35-day chronic NOAEC and LOAEC were 23.4 and 47.6 μg a.i./L, 

respectively. 

No chronic toxicity studies of penflufen’s formulations or degradates in freshwater fish were 

submitted. 
-Page 41 of 115- 

3.3.1.2. Toxicity to Freshwater Invertebrates 

Acute Effects 

 

An acute toxicity study (MRID 48023574; Acceptable) using Daphnia magna (neonates, <24 

hours old) is available for penflufen. Daphnids were exposed under static conditions for 48 

hours to mean measured concentrations of < 0.025 (control and solvent control), 0.30, 0.61, 1.26, 

2.33 and 4.66 mg a.i./L. Due to limited solubility of penflufen in the laboratory dilution water, 

no concentrations higher than nominal 5 mg a.i./L could be tested. Dimethylformamide was the 

solvent used to prepare the test solutions (0.1 mL/L). The only treatment related effects were at 

the highest concentration where 20% immobilization (4 of 20) was reported. The 15 of the 

surviving waterfleas exhibited one or more clinical symptoms (only 1 normal daphnid). Clinical 

symptoms included quiescence, abnormal position on the bottom of the vessel, and pale in color. 

The 48-h EC50 for Daphnia magna was determined to be greater than 4.66 mg a.i./L. Penflufen 

is classified as moderately toxic to daphnids on an acute exposure basis. The observed NOAEC 

is 2.33 mg ai/L. 

An acute toxicity study (MRID 48023577; Acceptable) using juvenile crayfish (Procambarus 

clarkii) is available for penflufen. One replicate of 10 crayfish were exposed under static 

conditions for 96 hours to mean measured concentrations of <0.03 (control and solvent control), 

0.31, 0.64, 1.16, 2.3 and 4.5 mg a.i./L. The organisms were not fed during the test. Due to 

limited solubility of penflufen in the laboratory dilution water, no concentrations higher than 

nominal 5 mg a.i./L could be tested. Dimethylformamide was the solvent used to prepare the test 

solutions (0.1 mL/L). The crayfish were observed for mortalities and sublethal effects at 4, 24, 

48, 72 and 96 hours. All surviving crayfish were normal. There were only two mortalities during 

the study and both mortalities were suspected to be due to cannibalism. On Day 4, one crayfish 

in the solvent control and one in the 4.5 mg a.i./L concentration group were noted as dead. The 

96-hour LC50 for crayfish was determined to be greater than 4.5 mg a.i./L). Penflufen is 

classified as moderately toxic to crayfish on an acute exposure basis. 

Degradates 

An acute toxicity study (MRID 48023575; Acceptable) with the degradate penflufen-pyrazolylAAP is available. Six replicates of Daphnia magna (neonates, <24 hours old) were exposed 

under static conditions for 48 hours to mean measured concentrations of <0.0104 (control), 

0.709, 1.42, 1.52, 1.33, and 3.12 mg a.i./L. No solvent was used in this study. There were no 

treatment related effects at any test concentration. The 48h EC50 of penflufen-pyrazolyl-AAP on 

Daphnia magna was determined to be greater than 3.12 mg a.i./L 

A 48h acute toxicity study (MRID 48023576; Acceptable) with the degradate penflufen-3-

hydroxy-butyl. Daphnids were exposed to mean measured concentrations of < 0.5 (control), 

3.30, 6.8, 14, 28 and 62 mg a.i./L. There were no treatment related effects at any test 

concentration. The 48h EC50 of penflufen-3-hydroxy-butyl on Daphnia magna was determined 

to be greater than 62 mg a.i./L. 
-Page 42 of 115- 

Although the existence of non-definitive values for Daphnia EC50 with parent penflufen and its 

degradates prevents precise comparisons from being made, there is no evidence to indicate 

greater toxicity of degradates to Daphnia compared to parent chemical. There are no data on the 

effect of formulations on daphnids. 

Chronic Effects 

A chronic life-cycle study (MRID 48023587; Supplemental) is available for daphnids. Daphnia 

magna (1st instars <24 hours old, 25 animals per study group) were exposed in a static-renewal 

test system (3 renewal intervals per week) for 21 days to mean measured test concentrations of 

<0.006 (control and solvent control), 0.10, 0.18, 0.37, 0.74, and 1.53 mg a.i./L. No dose related 

behavioral/sublethal effects were observed in any of the parental test groups and controls. One 

daphnid each in the control and 0.10 mg a.i./L group were found to be immobilized. The 

daphnid in the 0.10 mg a.i./L group was killed due to handling error. At study termination, mean 

lengths ranged between 5.11 and 5.26 mm while mean dry weights ranged between 1.266 to 

1.545 mg. There were no statistically significant difference in the growth end-points between the 

pooled control group and any of the treatment groups. Time to first brood was six days for all 

control and test groups except the 1.53 mg a.i./L group, where time to first brood was at day 

seven. Penflufen did not negatively affect the time to first brood for daphnids. Therefore, the 

NOAEC is 1.53 mg ai/L and the LOAEC is >1.53 mg ai/L 

No chronic toxicity studies of penflufen formulations or degradates using freshwater aquatic 

invertebrates were submitted. 

Benthic Organisms 

A 10-day study (MRID 48023590; Acceptable) evaluating benthic stage survival and growth of 

the midge (Chironomus dilutus) was performed with hard water and artificial sediment in a flowthrough test system which renewed the overlying water. The exposure to penflufen was via 

spiked sediment. The sediment concentrations were mixed and equilibrated over a 21-day period 

at the nominal concentrations of control, solvent control, 6.25, 12.5, 25, 50 and 100 mg a.i./kg 

dry weight sediment. There were 10 replicates per treatment level; 8 for biological observations 

and 2 for measured concentration analysis. Each test vessel/glass beaker received a 100-mL 

aliquot of spiked sediment and then a 175-mL aliquot of clean, overlying water was added. 

 

On Day 0, the organisms were impartially selected and added to each of the 8 replicates which 

were designated for biological observations. Each vessel contained 10 second- and third-instar 

larvae (with at least 50% of the organisms at 3rd instar) that were collected 11 days after 

hatching. The 10-day study included observations of midge behavior and survival and 

measurements of ash-free dry weight. These data were used to determine the LC50 or IC50, 

NOAEC and LOAEC based on pore water concentrations and sediment concentrations. Mean 

measured concentrations for sediment, pore water and overlying water were conducted on Day-0 

and a Day-10 of the study. The compound was stable in the sediment over the 10-day midge 

exposure. The mean measured concentrations in the sediment were control and solvent control 
-Page 43 of 115- 

(<0.60), 3.99, 8.51, 17.7, 34.4 and 63.8 mg a.i./kg dry weight sediment. The mean measured 

concentrations in the pore water were control and solvent control (<0.01), 0.38, 0.78, 1.97, 4.07 

and 8.28 mg a.i./L; and in the mean overlying water concentrations were control and solvent 

control (<0.01), 0.02, 0.04, 0.09, 0.16, and 0.35 mg a.i./L. 

During 10-days of flow-through exposure to the spiked sediments there were no clinical 

symptoms of toxicity noted in the surviving larvae in any control or treatment group. One dead 

midge was found on the sediment surface on day 8 in the 34.4 mg a.i./kg dry weight sediment 

group. At study termination (day 10), mortality was 2% in the controls and 0% in the solvent 

control. Mortality in the treatment groups was 5, 2, 5, 6, and 7% in the 0.38, 0.78, 1.97, 4.07 and 

8.28 mg a.i./L pore water concentrations, respectively. Midge survival in the highest 

concentration was significantly reduced when compared with the pooled control. The LC50 was 

greater than 8.28 mg ai/L pore water. The NOAEC for survival was 4.07 mg a.i./L pore water 

concentration. 

Midge growth at study termination, as measured by ash-free dry weight, was inhibited -13, 7.0, 

20, -2.0, and 21% in the 0.38, 0.78, 1.97, 4.07 and 8.28 mg a.i./L pore water concentrations, 

respectively, when compared to the pooled control. The IC50 for growth is greater than 8.28 mg 

ai/L pore water; the NOAEC for growth was 0.78 mg a.i./L based on pore water concentrations. 

The most sensitive endpoint in the 10-day study was midge growth. 

3.3.1.3. Toxicity to Estuarine/Marine Fish 

Acute Effects 

An acute toxicity study (MRID 48023586; Acceptable) with sheepshead minnow (Cyprinodon 

variegatus) is available for penflufen. Fish were exposed to mean measured concentrations of 

<0.012 (control and solvent control), 0.116, 0.21, 0.43, 0.82, 1.92 and 3.45 mg a.i./L. 

Dimethylformamide was used as solvent at the concentration of 0.1 mL/L in each test level 

except for the water control. There were no precipitates in any of the test solutions. No 

mortality or clinical signs of toxicity were observed in the control, solvent control, 0.12, 0.21, 

and 0.43 mg a.i./L groups. Mortality was 10, 100, and 100% in the 0.82, 1.92, and 3.45 mg a.i./L 

groups. Clinical signs of toxicity were also noted in the 0.82, 1.92 and 3.45 mg a.i./L groups. The 

symptoms noted included vertical orientation, on bottom, at surface, labored respiration and 

quiescence. The 96-hour NOAEC was 0.43 mg a.i./L and the 96-hour LC50 calculated by 

binomial probability was 1.15 mg a.i./L. Penflufen is classified as moderately toxic to 

sheepshead minnow on an acute exposure basis. 

Chronic Effects 

 No chronic toxicity tests in estuarine/marine fish with the TGAI, formulations, or 

degradates were submitted. 
-Page 44 of 115- 

3.3.1.4. Toxicity to Estuarine/Marine Invertebrates 

Acute Effects 

An acute toxicity study (MRID 48023578; Acceptable) using Eastern oysters (Crassostrea 

virginica) is available for penflufen. Oysters were exposed under flow-through conditions for 96 

hours to mean measured concentrations of < 0.1 (control and solvent control), 0.23, 0.44, 0.90, 

1.4 and 3.2 mg a.i./L. There were no mortalities among oysters in any treatment or control 

groups during the test. All oysters appeared normal throughout the 96-hour exposure period. 

After 96 hours, the mean shell deposition were 3.3, 3.3, 2.3, 2.9, 2.1, 1.3, and 1.4 mm in the 

control, solvent control, 0.23, 0.44, 0.90, 1.4 and 3.2 mg a.i./L treatment groups, respectively. 

Percent inhibition of shell growth relative to the pooled control data in the 0.23, 0.44, 0.90, 1.4 

and 3.2 mg a.i./L treatment groups was 30, 11, 35, 61 and 57%, respectively. There was no 

statistical difference in growth between the pooled control and the 0.44 mg a.i./L treatment 

group. There was a statistically significant reduction in shell growth in the 0.23, 0.90, 1.4 and 3.2 

mg a.i./L treatment groups in relation to the pooled control. Although there was a statistically 

significant reduction in growth in the 0.23 mg a.i./L treatment group relative to the pooled 

control, this reduction was not considered to be treatment related as shell growth was not 

statistically significantly reduced in the next highest test group (0.44 mg a.i./L). The 96-hour 

EC50 was calculated to be 1.3 mg a.i./L. The NOAEC was considered to be 0.44 mg a.i./L. The 

96-hour EC50 was calculated to be 1.3 mg a.i./L. Penflufen is classified as moderately toxic to 

Eastern oysters on an acute exposure basis. 

A 96h acute toxicity study (MRID 48023579; Acceptable) using mysid shrimp (Americamysis 

bahia) is available for penflufen. Mysids were exposed under flow-through conditions to mean 

measured concentrations of < 0.025 (control and solvent control), 0.45, 0.76, 1.4, 2.6 and 4.7 mg 

a.i./L.. Due to limited solubility of penflufen in the laboratory dilution water, no concentrations 

higher than nominal 5 mg a.i./L could be tested. Dimethylformamide was the solvent used to 

prepare the test solutions (0.1 mL/L). At study termination, one mysid was dead (5% mortality) 

in the negative control group. No mortalities were observed in the solvent control, 0.45, 0.76, 

and 1.4 mg a.i./L groups. Mortality was 55% (11 dead) and 100% in the 2.6 mg a.i./L and 4.7 mg 

a.i./L test groups, respectively. Clinical symptoms of toxicity including erratic swimming, lying 

on the bottom of the chamber, and reduced growth compared to the controls were noted in the 

2.6 and 4.7 mg a.i./L test groups. One mysid was noted with erratic swimming in the 0.76 mg 

a.i./L group only on day 3. All mysid shrimp appeared normal in the 0.76 mg a.i./L group at 

study termination. No other sublethal effects were noted in the study. The 96-hour LC50 value 

was 2.5 mg a.i./L and the 96-hour NOAEC was 1.4 mg a.i./L. Penflufen is classified as 

moderately toxic to mysids on an acute exposure basis. 

3.3.1.5. Toxicity to Aquatic Plants 

Studies were submitted for a freshwater vascular plant (duckweed, Lemna gibba) and a green 

algae (Pseudokirchneriella subcapitata). Species typically used to evaluate risk to also include a 

cyanobacteria (Anabaena flos-aquae), a freshwater diatom (Navicula pelliculosa) and a marine 

alga (Skeletonema costatum). That studies on these three taxa have not been submitted increases 
-Page 45 of 115- 

the uncertainty in the risk assessment. 

Four studies on green algae were submitted: one on technical penflufen, one on the formulated 

product PEN 240FS, one each on the degradates AAP and pen-3HB. 

Vascular Aquatic Plants

A study (MRID 48023603; Acceptable) examining the effect of technical penflufen on the 

aquatic macrophyte duckweed (Lemna gibba G3) was submitted. Three replicates with an initial 

cell density of 1 x 104

 cells/mL were exposed to penflufen, under static (shaken cultures) 

conditions, for 96 hours. Mean measured concentrations were control and solvent control 

<0.015, 0.27, 0.54, 1.1, 2.4 and 4.7 mg a.i./L. The test solutions were renewed on Day 3 of the 

study and the compound was stable in the test system. There were no compound related 

phytotoxic effects noted in the study. All fronds appeared normal during observations on days 0 

and three. On study day five and seven, several fronds in one of the control vessels (replicate A) 

appeared brown and/or transparent. This effect was isolated to this replicate vessel and did not 

appear to have an effect on the frond number or dry weights of the plants in this test replicate. 

Plants were normal in all other test vessels and test levels. 

After seven days, the mean frond numbers were 184.2, 167.7, 169.3, 174.0, 166.0, and 142.3 in 

the pooled control, 0.27, 0.54, 1.1, 2.4, and 4.7 mg a.i./L treatment groups, respectively. Percent 

inhibition of frond numbers were 9.0, 8.1, 5.5, 9.9, and 22.7% in the 0.27, 0.54, 1.1, 2.4, and 4.7 

mg a.i./L treatment groups, respectively, as compared to the pooled control. Inhibition of mean 

cumulative biomass was 9.5, 7.8, 5.9, 9.5, and 18.6% in the 0.27, 0.54, 1.1, 2.4, and 4.7 mg a.i./L 

treatment groups, respectively, as compared to the pooled control, and inhibition of mean growth 

rate was 3.4, 3.1, 2.3, 3.8, and 9.5% for the corresponding treatment groups, respectively, when 

compared to the solvent control group. Mean frond count in the 4.7 mg a.i./L group was 

statistically significant reduced when compared to the pooled controls. Mean dry weight was 

1.012, 1.036, 1.021, 1.014, 1.018, and 1.014 g in the pooled control, 0.27, 0.54, 1.1, 2.4, and 4.7 

mg a.i./L treatment groups, respectively. There were no statistically significant difference 

between the pooled control and any of the treatment groups for mean dry weight. The 7-day EC50

values for all endpoints in the duckweed study were >4.7 mg a.i./L which was the functional 

limit of solubility in the test system. The NOAEC for frond count/number, cumulative biomass 

and growth rate were all 2.4 mg a.i./L. Frond count/number, cumulative biomass and growth rate 

were the most sensitive endpoints in this study. 

Nonvascular Aquatic Plants

A study (MRID 48024007; Supplemental due to only being 72h) examining the effect of 

formulated penflufen (PEN240FS; 22.7% a.i.) on green algae, Pseudokirchneriella subcapitata, 

was submitted. Three replicates with an initial cell density of 1 x 104

 cells/mL were exposed to 

penflufen, under static (shaken cultures) conditions, for 72 hours. Mean measured 

concentrations were control and solvent control (<0.015 mg a.i./L), 0.510, 1.51, 3.90, 9.42, and 

24.8 mg a.i./L. Cell density was determined daily in each of the three test replicates at each test 

concentration. Inhibition of growth rate relative to the control growth rate was 0.0, -1.4, 4.3, 2.3, 
-Page 46 of 115- 

and 41.0% for the 0.510, 1.51, 3.9, 9.42, and 24.8 mg a.i./L treatment groups, respectively. The 

72-hour EC50 and NOAEC for cell density inhibition were 7.5 and 1.51 mg a.i./L, respectively. 

The 72-hour EC50 and NOAEC for the inhibition of growth rate were > 24.8 and 1.51 mg a.i./L, 

respectively. 

A study (MRID 48023604; Acceptable) examining the effect of penflufen technical on green 

algae, Pseudokirchneriella subcapitata, was submitted. Three replicates with an initial cell 

density of 1 x 104 cells/mL were exposed to penflufen, under static (shaken cultures) conditions, 

for 96 hours. Mean measured concentrations were control and solvent control (<0.015 mg 

a.i./L), 0.14, 0.28, 0.52, 0.99, 2.3 and 5.1 mg a.i./L. Mean measured recoveries were within the 

range of 91-95% of the nominal concentrations. Cell density was determined daily in each of the 

three test replicates at each test concentration. Parameters measured included cumulative 

biomass, growth rate, and cell density at 96 hours. The 96-hour EC50 value values for growth 

rate and cumulative biomass were >5.1 mg a.i./L with the NOAEC value of 0.52 mg a.i./L, based 

on biomass and cell density inhibition. 

 Degradates 

A study (MRID 48023606; Supplemental because the study was conducted for 72h) examining 

the effect of the degradate penflufen-pyrazolyl-AAP on green algae, Pseudokirchneriella 

subcapitata, was submitted. Three replicates with an initial cell density of 1 x 104

 cells/mL were 

exposed to penflufen, under static (shaken cultures) conditions, for 72 hours. Mean measured 

concentrations were control and solvent control (LOQ 5.2 μg a.i./L), 9.42, 34.4, 98.3, 320, and 

1071.5 μg a.i./L. Mean measured recoveries were within the range of 91-95% of the nominal 

concentrations. The 72 EC50 values were calculated based on the mean measured concentrations. 

At the highest test concentration (1071.5 μg a.i./L), the inhibition of growth rate and % biomass 

were only 3 and 11.9% respectively. As a result, reliable confidence intervals could not be 

calculated. The 72-hour EC50 values for growth rate and cumulative biomass were >1071.5 μg 

a.i./L. The NOAEC was 98.3 μg a.i./L. 

A study (MRID 48023605; Supplemental because the study was conducted for 72h) examining 

the effect of the degradate penflufen-3-hydroxy-butyl on green algae, Pseudokirchneriella 

subcapitata, was submitted. Three replicates with an initial cell density of 1 x 104

 cells/mL were 

exposed to penflufen, under static (shaken cultures) conditions, for 72 hours. Mean measured 

test concentrations were control, 4.3, 8.4, 16.8, 35.8, and 71.9 mg a.i./L. No solvent was used in 

the preparation of the test solutions. Based on the limited solubility of the pure metabolite in 

algal media, the highest possible test concentration was 75 mg/L. The 72-hour EC50 value for 

cell density was 60.8 mg a.i./L, the most sensitive endpoint. The NOAEC was 16.8 mg a.i./L. 

3.3.2 Terrestrial Effects Characterization 

The most sensitive acute and chronic toxicity reference values associated with penflufen 

exposure to mammals, birds, and terrestrial invertebrates are summarized in Table 3.12. The 

most sensitive measurement endpoints for terrestrial plants are presented in Table 3.13. 
-Page 47 of 115- 

Penflufen is practically non-toxic to Norway rat (Rattus norvegicus) on an acute exposure basis. 

A two-generation study on reproduction and fertility in the rat showed penflufen to cause chronic 

toxicity effects in the parents and F1 and F2 generations that would impact adult body weights 

and reduced litter size. 

Studies of acute oral (dose-based) toxicity in bobwhite quail (Colinus virginianus) and canary 

(Serinus canaria) indicated that penflufen is practically nontoxic to bobwhite quail and canary 

when administered a single oral dose. Two subacute dietary toxicity studies indicate that 

penflufen TGAI is also practically nontoxic to mallard duck (Anas platyrhynchos) and bobwhite 

quail on a subacute dietary exposure basis. For chronic effects, no effects were observed in the 

bobwhite quail study, but treatment-related effects on number of eggs hatched per live embryo in 

the reproduction toxicity study of penflufen TGAI in mallard duck were noted at all test 

concentrations; therefore, a definitive NOAEC value was not derived in the study. No studies of 

the formulations or the degradates were submitted; all measurement endpoints for avian species 

are based on technical grade penflufen. 

Results of available toxicity studies indicate that penflufen TGAI is practically nontoxic to honey 

bees (Apis mellifera) on an acute exposure basis, though there are effects on the fecundity of 

Aphidius rhopalosiphi, a parasitoid wasp, and earthworms (Eisenia foetida) on an acute contact 

exposure basis. 

Tier I limit studies of the effect of the penflufen formulation PEN 240FS on seedling emergence 

and vegetative vigor in terrestrial plants were submitted, indicating that terrestrial plants are 

relatively insensitive to penflufen at application rates slightly less than the maximum per acre 

application rate for the proposed registration uses. 

Table 3.12. Penflufen Technical Grade Toxicity Measurement Endpoints for Terrestrial 

Animals. 

Exposure 

Scenario 

Species Exposure 

Duration 

Toxicity Reference Value MRID 

(Classification) 

Mammals 

Acute 

(Dose-based) 

Laboratory rat Single oral dose LD50 > 2000 mg a.i./kg bw MRID 40823749 

Acceptable 

Chronic 

(Dietary-based) 

Laboratory rat Two-generation NOAEL = 1000 mg/kg diet 

LOAEL = 4000 mg/kg diet 

Endpoints based on decreased 

parental, decreased litter size 

MRID 48023812 

Acceptable 

Birds 

Acute 

(Dose-based) 

Bobwhite quail 

Colinus 

virginianus

14-day single 

oral dose 

LD50 >4000 mg a.i./kg bw 

NOAEL: 2000 mg a.i./kg bw 

(based on female body weights) 

MRID 48023591 

(Acceptable) 

Acute 

(Dose-based) 

Canary 

Serinus 

canaria 

14-day single 

oral dose 

LD50 >2000 mg a.i./kg bw 

NOAEL: 2000 mg a.i./kg bw 

MRID 48023592 

(Supplemental) 
-Page 48 of 115- 

Table 3.12. Penflufen Technical Grade Toxicity Measurement Endpoints for Terrestrial 

Animals. 

Exposure 

Scenario 

Species Exposure 

Duration 

Toxicity Reference Value MRID 

(Classification) 

Acute 

(Dietary-based) 

Bobwhite quail 

Colinus 

virginianus

8-day dietary LC50: >8944 mg ai/kg diet 

NOAEC: 8944 mg ai/kg diet 

MRID 48023593 

(Acceptable) 

Mallard duck 

Anas 

platyrhynchos 

8-day dietary LC50: >9923 mg ai/kg diet 

NOAEC: 4613 mg ai/kg diet 

(based on treatment related 

effects on body weight and feed 

consumption) 

MRID 48023594 

(Acceptable) 

Chronic 

(Dietary-based) 

Mallard duck 

Anas 

platyrhynchos

ca. 22 week 

avian 

reproduction 

study 

LOAEC: 292 mg ai/kg diet 

NOAEC: < 292 mg ai/kg diet 

(based on %hatch /live embryo 

and %hatch/eggs set) 

MRID 4823596 

(Supplemental) 

Bobwhite quail 

Colinus 

virginianus

ca. 21 week 

avian 

reproduction 

study 

LOAEC: >946 mg ai/kg diet 

NOAEC: 946 mg ai/kg diet 

MRID 48023595 

(Acceptable) 

Terrestrial Invertebrates 

Acute 

(Contact) 

Honeybee 48-hour LD50 >100 μg a.i./bee 

NOAEL: 100 μg ai/bee 

MRID 40823597 

(Acceptable) 

Acute 

(Oral) 

Honeybee 48-hour LD50 >108 μg a.i./bee 

NOAEC: 108 μg ai/bee 

MRID 40823597 

(Acceptable)

Acute Earthworm 14-day LC50 > 1,000 mg a.i./kg dw soil 

NOAEC: 316 mg a.i./kg dw soil 

LOAEC: 562 mg a.i./kg dw soil 

MRID 48023611 

(Supplemental)3 

 

Table 3.13. Penflufen Toxicity Measurement Endpoints for Terrestrial Plants. 

Exposure 

Scenario 

Formulation Species Exposure 

Duration 

Toxicity Reference Value Reference 

(Classification) 

Seedling 

Emergence 

PEN 240FS None 

affected 

21-day test -

single 

application 

EC25 >0.22 lbs a.i./A 

NOAEC = 0.22 lbs a.i./A 

MRID 48023601 

(Acceptable) 

Vegetative 

Vigor 

PEN 240FS None 

affected 

21-day test - 

single 

application 

EC25 >0.22 lbs a.i./A 

NOAEC = 0.22 lbs a.i./A 

MRID 448023598 

(Acceptable) 

3.3.2.1. Toxicity to Mammals 

Acute Effects

An acute oral toxicity study is available for using female rats were submitted for penflufen. The 

study (MRID 48023749; Acceptable) derived a 14-day oral LD50 value of > 2,000 mg a.i./kg bw. 

The study was conducted after OECD 423, with rat each given a single oral dose of 2,000 mg/kg 

bw. No clinical signs or toxicological effects on body weight or weight gain were observed, and 

no gross pathological changes in animals sacrificed were observed. 
-Page 49 of 115- 

Additional product mixtures were tested including PEN 24FS (MRID 48024102), penflufen plus 

prothioconazole plus metalaxyl (MRID 48024302), penflufen plus prothioconazole (MRID 

48024402) penflufen plus trifloxystrobin (MRID 4824502) and penflufen plus clothianidin 

(MRID 48024602). While none were an actual final product formulation, they represent a suite 

of ‘typical’ coformulants, each in relative amounts found in products, mixed in water and 

administered by gavage. Each study resulted in an LD50 > 2000 mg mixture/kg-bw.

Chronic Effects 

An acceptable 2-generation Wistar rat (Ratus norvegicus) reproduction and fertility effects study 

using penflufen technical was submitted to establish the toxicity of penflufen to mammals over 

prolonged periods (MRID 48023812). Thirty rats/sex/dose via the diet at nominal dietary 

concentrations of 0, 200, 1000, or 4000 ppm [equivalent to 0, 12.8, 64.1, or 252.2 mg/kg/day 

(males)/ 0, 15, 75.9, or 294.5 mg/kg/day (females)] throughout the 10-week pre-mating period 

and to the dams through gestation and lactation. There was one set of litters per generation. The 

parental systemic LOAEL is 4000 ppm based on decreased body weight, decreased body weight 

gain (both generations). The parental systemic NOAEL is 1000 ppm. The offspring LOAEL is 

4000 ppm based on a slight decrease in litter size in both generations, decreased pup body weight 

and pup body-weight gain. The offspring NOAEL is 1000 ppm. There was no treatment-related 

effect on reproductive performance in either the P or the F1-generation. The reproductive 

NOAEL is 4000 ppm, the highest dose tested. 

3.3.2.2. Toxicity to Birds 

Acute and Subacute Dietary 

An acute oral toxicity study (MRID 48023591; Acceptable) was conducted with16-week old 

adult northern bobwhite quail (Colinus virginianus). Penflufen technical (purity 95.6%) was 

applied via single oral administration in gelatin capsules, ten birds per treatment level (five males 

and five females), caged by dose and by sex. The treatments included a control (empty gelatin 

capsule), and three dose levels of 1000, 2000 and 4000 mg a.i./kg-bw. All birds were given 

equivalent numbers of gelatin capsules (i.e., four capsules) as determined by the number needed 

to accommodate the test material for the highest treatment group. No solvents were used for the 

treatments and no regurgitation was observed following treatment. The study duration was 14 

days. There were no clinical symptoms of toxicity, no mortality and no gross pathological 

symptoms at necropsy in any dose group or the controls. There was reduced food consumption 

and reduced body weight and growth in the females at the highest treatment level of 4000 mg 

a.i./kg bw. The 14-day acute oral LD50 of penflufen in northern bobwhite was >4000 mg a.i./kgbw. The NOAEL, based on reduced female body weights and feed consumption, was 2000 mg 

a.i./kg-bw. Penflufen is classified as practically nontoxic to bobwhite quail on an acute exposure 

basis. 

An acute oral toxicity study (MRID 48023592) was conducted with canaries (Serinus canaria). 

The study is classified as Supplemental due to a prolonged pre-test fasting period; however this 
-Page 50 of 115- 

did not seem to adversely affect the control birds. Penflufen was administered via single oral 

dose (in a gelatin capsule) to adult canaries. Ten birds (five males and five females) were dosed 

in the control and in the limit dose group at 2000 mg a.i./kg-bw. The control was dosed with 

empty gelatin capsules. The gelatin capsule was coated with corn oil before administering to the 

birds. No regurgitation was observed following dose administration. The study duration was 14 

days. No symptoms of toxicity were observed in the control and treatment group. No mortality 

occurred in the treatment group. There was one death in the control group (female) on day 3. 

This mortality was attributed to injuries sustained during dose administration. The 14-day acute 

oral LD50 of penflufen in canary was >2000 mg a.i./kg-bw. The NOAEL was 2000 mg a.i./kgbw. Penflufen is classified as practically nontoxic to canary on an acute exposure basis. 

A subacute dietary study (MRID 48023593; Acceptable) was conducted with northern bobwhite 

quail (10-day-old hatchlings, 10 hatchlings per test level). Birds were exposed for five days to 

feed with mean measured dietary test concentrations of 0 (control), 659, 1106, 2319, 5394, and 

8944 mg a.i./kg diet, which was equivalent to a daily dietary dose of 0, 125, 212, 445, 1005, and 

1697 mg a.i/kg bw/day, respectively. The exposure period was followed by a 3-day subsequent 

recovery phase on untreated feed. No clinical signs of toxicity or treatment-related mortalities 

were noted at any treatment level. There were no statistically significant reductions in body 

weight or growth during the exposure period at any treatment level. There was no treatment 

related reduction in feed consumption at any treatment level. Post-mortem examinations revealed 

no treatment related gross lesions or unusual observations. The sub-acute dietary LC50 of 

technical penflufen in northern bobwhite was > 8944 mg a.i./kg-diet or >1697 mg a.i./kg-bw. 

Based on all parameters measured, the NOAEC was 8944 mg a.i./kg-diet. Penflufen is classified 

as practically nontoxic to bobwhite quail on an acute dietary exposure basis. 

A subacute dietary study (MRID 48023594; Acceptable) was conducted with mallard ducks 

(Anas platyrhynchos). Ten-day-old ducklings, 10 per diet group were exposed to measured 

concentrations of 0 (<LOQ), 692, 1337, 2698, 4613 and 9923 mg a.i./kg-diet and were 

equivalent to a dietary dose of 0 (control), 144, 308, 586, 1046, and 2208 mg a.i./kg bw/day, 

respectively. No clinical signs of toxicity or treatment-related mortalities were noted at any 

treatment level. There was no treatment related reduction in feed consumption at any treatment 

level. Post-mortem examinations revealed no treatment related gross lesions or unusual 

observations. There were no body weight or food consumption effects at treatment levels 692, 

1337, 2698 and 4613 mg a.i./kg diet as compared to the controls. During the Day 5 exposure 

period, mean growth and body mass were significantly lower in the 9923 mg a.i./kg feed 

treatment level as compared to the control group. Feed consumption in the 9923 mg a.i./kg 

treatment level was also decreased as compared to the control group during the exposure periods. 

All birds recovered in body mass and growth when given untreated diet. The food consumption 

was less as compared to the control by the end of the recovery period (Day 8). The sub-acute 

dietary LC50 for mallard duck was >9923 mg a.i./kg diet or >2208 mg a.i./kg body weight. Based 

on body weight and food consumption during the exposure phase of the study, the NOAEC was 

4613 mg a.i./kg diet (1046 mg a.i./kg body weight/day). Penflufen is classified as practically 

nontoxic to mallard duck on an acute dietary exposure basis. 
-Page 51 of 115- 

Chronic 

A one generation avian reproduction toxicity study (MRID 48023595; Acceptable) was 

conducted with the northern bobwhite quail. Young (17-week old) quail were acclimated to test 

conditions for two weeks prior to the start of the study. Eighteen pairs of birds were introduced to 

penflufen treated feed at 19-weeks of age and were exposed for approximately 22 weeks to mean 

measured dietary concentrations of 0 (control), 226, 461 and 946 mg a.i./kg-diet. These values 

correspond to daily dietary dose levels of 0, 23, 47 and 96 mg a.i./kg body weight/day, 

respectively. There were no treatment related adverse effects on the health or reproductive 

capacity of adult bobwhite quail. Additionally, no treatment related effects were noted on 

hatchling health, growth, or survival of bobwhite quail. The NOAEL was 946 mg a.i./kg feed (96 

mg a.i./kg bw/day). The LOAEL was >946 mg a.i./kg feed (>96 mg a.i./kg bw/day). 

A one generation avian reproduction toxicity study (MRID 48023596; Supplemental) was 

conducted with mallard duck. The birds were 18 weeks old when introduced to penflufen-treated 

feed and were exposed for approximately 21 weeks to mean measured dietary concentrations of 

control 0, 262, 502, 1049 mg a.i./kg feed. These values correspond to daily dietary dose levels of 

0, 27, 45, and 95 mg a.i./kg body weight/day, respectively. There were no treatment related 

adverse effects on the health or reproductive capacity of adult mallard duck. For hatchling effects, 

initial hatchling body weight and percentage of 14-day survival of eggs set were significantly 

lower in hatchlings in the 45 mg a.i./kg body weight/day treatment group when compared to the 

controls (Dunnett’s Test). As there were no significant difference in the corresponding hatchling 

end-points in the 95 mg a.i./kg body weight/day, these differences were not considered to be 

treatment related. The percent hatching survival of eggs set was significantly different for the 45 

mg a.i./kg body weight/day treatment group when compared to the controls (Mann-Whitney Test). 

As there was no significant difference in the 27 and 95 mg a.i./kg body weight/day treatment 

groups when compared to the controls, this difference in the percent hatching survival of eggs set 

was not considered to be biologically relevant. The percent hatch of live embryo was significantly 

different for the 27 and 95 a.i./kg body weight/day treatment groups when compared to the controls 

(Mann-Whitney test) while all test groups were significantly different (9%) than the control group 

for percent hatch of eggs set (Jonckheere test). For the ratio of hatchlings to live embryos, 

reductions from control ranged from 9 to 18%, with significant effects at the 262 (p=0.007) and 

1049 (p=0.029) mg ai/kg diet levels. For the ratio of hatchling survivors to eggs set, reductions 

ranged from 10 to 15% of control with only a significant effect (p=0.033) at the 502 mg ai/kg 

diet level, but a trend toward a significant effect was noted at the 263 (p=0.059) and 1049 

(p=0.091) mg ai/kg levels. A reduction in hatchling weight was only apparent at the 502 mg 

ai/kg diet level (5%; p=0.044). These results when taken together indicates an NOAEC <262 mg 

ai/kg diet and a LOAEC of 262 mg ai/kg diet. No other treatment related effects were noted on 

hatchling health, growth, or survival of mallard duck. 
-Page 52 of 115- 

3.3.2.3. Toxicity to Terrestrial Invertebrates 

Acute Effects 

Honey bee 

The oral and contact toxicity of penflufen towards honey bees (Apis mellifera) was studied over 

a 48 hour period (MRID 48023597; Acceptable). Honey bees (5 replicates of 10 bees per group) 

were exposed to penflufen formulation topically via the thorax (contact) or in the feed solution 

(oral) in a limit test. The dose for the contact test was 100 μg a.i./bee while the test item dose for 

the oral test, based on the actual intake was 108.2 μg a.i./bee. Acetone was used as the organic 

solvent. A test with a toxic reference (Perfekthion, a formulation of the active substance 

dimethoate) was conducted in parallel. Endpoints were mortality and behavior of the bees 

compared to control up to 48 hours after application. 

In the contact toxicity test 0% mortality was observed at 100 μg a.i./bee after 48 hours. No 

mortality occurred in the solvent control and the water control, respectively. There were no 

behavioral abnormalities in the exposed bees or the controls at any time during the test. In the 

oral toxicity test no mortality or behavioral abnormalities occurred in the treated bees or controls 

at any time during the study. The 48-h NOEL and LD50 of penflufen technical were 100 and 

>100 μg a.i./bee in the contact toxicity test, respectively. The 48-h NOEL and LD50 in the oral 

toxicity test were 108.2 and >108.2 μg a.i./bee, respectively. 

Parasitoid wasp 

The formulated product PEN 240FS (containing 22.8% w/w penflufen) was studied on 48-hour 

old adults of the parasitoid wasp Aphidius rhopalosiphi under laboratory conditions (MRID 

48023607; Supplemental). Glass plates were treated at rates of 0.01, 0.03, 0.05, 0.11 and 0.22 

lbs a.i./A in 200 L deionized water and allowed to dry. The parasitoid wasp Aphidius 

rhopalosiphi were then exposed to the spray residues. The control group was treated with 

deionized water (200 L/ha). Dimethoate EC 400 (0.1 g a.i./ha in 200 L water/ha) was used as a 

toxic reference item. Four replicates of 15 wasps (per treatment group) were exposed to the 

residues of the test item, reference item and control treatments, respectively. During the 

mortality test, the wasps were fed ad libitum with aqueous honey solution (25 % w/w honey). 

The condition of the adult wasps was assessed at 2, 24 and 48 hours after exposure. At the end of 

the 48 hours 15 impartially chosen females from the water control and treatment groups 15, 30, 

61, 124 and 250 g a.i./ha were transferred to a cylinder containing untreated barley plants 

infested with Rhopalosiphum padi for a period of 24 hours. The number of mummies was 

assessed 11 days later to evaluate the potential fecundity effects of PEN 240 FS. 

The rate of mortality of wasps after 48-h exposure to PEN 240FS was 3.3% (two deaths out of 

60) in the control group. The uncorrected rate of mortality was 3.3, 3.3, 3.3, 0.0, and 6.7% in 

treatment groups 0.01, 0.03, 0.05, 0.11 and 0.22 lbs a.i./A, respectively. Corrected mortality was 

0, 0, 0, 0, -3.4, and 3.4% for the control, 15, 30, 61, 124, and 250 g a.i/ha treatment groups, 

respectively. Statistical analysis (FISHER`s Exact test, 1-sided, p-values adjusted according to 
-Page 53 of 115- 

Bonferroni-Holm, p<0.05) revealed no significant differences concerning the mortality after 48 

hours between the control and all test item treatment groups. The LD50 of PEN 240 FS on the 

predatory wasp was, therefore, greater than 250 g a.i./ha. 

In the fecundity assessment after 48-h exposure of PEN 240FS, the mean number of mummies 

produced per wasp was 6.5, 5.3, 2.5, 2.8, 2.8, and 2.3 in the control, 0.01, 0.03, 0.05, 0.11 and 

0.22 lbs a.i./A treatment groups, respectively. The percent reduction in mean number of 

mummies produced per wasp between the control and the 0.01, 0.03, 0.05, 0.11 and 0.22 lbs 

a.i./A treatment groups were 18.4, 61.2, 57.1, 57.1, and 64.3%, respectively. There was a 

significant statistical difference between control and the 0.22 g ai/ha treatment level regarding 

the reduction of the number of parasitized aphids per female (Wilcoxon test, 2-sided, p-values 

adjusted according to Bonferroni-Holm, p<0.05). The lower treatments (0.01, 0.03, 0.05, and 

0.11 lbs a.i./A) resulted in no statistical difference as compared to the control. While this is not a 

guideline USEPA study, the data do indicate that there are reproductive effects at all rates tested, 

but that variability in the replicates (or the use of the Bonferroni correction) precluded sufficient 

statistical power to detect these effects. There are inhibitions of roughly 60% in the highest four 

rates. 

Predatory mites 

A study with protonymphs of the predatory mite Typhlodromus pyri is available for penflufen 

(48023609; Supplemental). The protonymphs were exposed to spray residues of PEN 240FS 

(22.8% a.s. w/w on glass plates). The spray application rates were 10.01, 0.03, 0.05, 0.11 and 

0.22 lbs a.i./A in 200 L deionized water/ha. The control was treated with deionized water (200 

L/ha). Dimethoate EC 400 (4 g a.i./ha in 200 L water/ha) was used as a toxic reference item. 

Protonymphs of T. pyri were exposed in 5 replicates of 20 mites (per treatment group) to the 

spray residues of the test item, reference item and control treatment, respectively. During the 

assessments the predatory mites were fed with pollen (birch – pine mixture). 

Mortality of 100 protonymphs was assessed 1, 4, 7, 10, 12 and 14 days after exposure by 

counting the number of living and dead mites. The number of escaped mites was calculated as 

the difference from the total number exposed. The reproduction rate of surviving mites was then 

evaluated over the period of 7-14 days after treatment by counting the total number of offspring 

(eggs and larvae) produced. 

All OECD TG226 validity criteria for conducting the laboratory test with Typhlodromus pyri

were met: The results of the control group indicated that the test organisms were in a good 

condition (mortality: 11%, reproduction: 5.8 eggs/female). The results of the toxic standard 

group indicated that the test system was sensitive to harmful substances (corrected mortality: 

83.1%). 

Seven days after study initiation, mortality of mites in the control group was 11%. The corrected 

mortality of mites were -2.2, 3.4, 7.9, 6.7, and 10.1% in the 0.01, 0.03, 0.05, 0.11 and 0.22 lbs 

a.i./A treatment groups, respectively. There were no statistically significant differences in 
-Page 54 of 115- 

mortality after 7 days between the control and all test item treatment groups. The LD50 was, 

therefore, > 0.22 lbs ai/A. 

The mean number of offspring produced per female after 14 days was 5.76, 6.69, 4.95, 5.31, 

5.97, and 3.62 in the control, 0.01, 0.03, 0.05, 0.11 and 0.22 lbs a.i./A treatment groups, 

respectively. The reduction of mean number of offspring relative to the control group was -16, 

14, 7.8, -3.6, and 37 for the 15, 30, 61, 124, and 250 g a.i./ha treatment groups, respectively. 

There was a statistically significant effect of the test item on reproduction at the highest 

application rate, only when compared to the control group, resulting in a NOAEC of 0.11 lbs 

ai/A. 

 Earthworms 

A 14-day earthworm study is available for penflufen (MRID 48023611; Supplemental). Adult 

earthworms (Eisenia fetida Andrei) (4 x 10 animals per concentration, the overall average weight 

was 0.35 g) were exposed for 14 days in artificial soil at nominal concentrations of 100, 178, 

316, 562 and 1000 mg ai/kg dry weight soil. The earthworms were observed for mortality, 

weight changes and abnormalities (e.g. changes in behavior). The animals were not fed during 

the study. 

No morphological or behavioral effects were observed. No mortality was observed in either the 

control or any of the treatment groups. At study termination, mean weights of the earthworms 

were 0.35, 0.36, 0.35, 0.33, 0.31, and 0.28 in the control, 100, 178, 316, 562, and 1000 mg a.i./kg 

dry weight soil groups, respectively. Earthworm weights in the 562 and 1000 mg a.i./kg dry soil 

groups were statistically significantly reduced relative to the control weights. The 14-day LC50 of 

penflufen technical on earthworms was >1000 mg a.i./kg dry weight soil and the NOAEC was 316 

mg a.i./kg dry weight soil. 

Formulation 

The effect of the formulated product Pen 240 FS on the survival, growth and reproduction of 

earthworms, Eisenia fetida, was studied over an eight week (56 day) period (MRID 48023612; 

Supplemental). Adult earthworms (approx. 7 months old, 8 x 10 animals for the control group 

and 4 x 10 animals per application rate of the treatment group) were exposed in an artificial soil 

(with 5 % peat content) to application rates of 57.8, 101.7, 180.3, 321.3, and 573.2 mg a.i./kg dry 

weight soil. After 28 days, the number of surviving adult animals and their weight alteration was 

determined. The adult earthworms were then removed from the artificial soil and after an 

additional 28 days, the number of offspring was determined. After 28 days of exposure, no 

adverse behavioral and morphological effects, and no mortality were observed in the adult 

earthworms in any of the control or treatment groups. Mean weights were statistically 

significantly reduced in the 312.3 and 573.2 mg a.i./kg dry weight soil treatment groups with 

respect to the control group (Dunnett’s method). No statistically significant difference in mean 

earthworm weights were observed between the control and the 57.8, 101.7 and 180.3 mg a.i./kg 

dry weight soil groups.
-Page 55 of 115- 

After eight weeks, there was no statistically significant difference in reproduction between the 

control and 57.8 mg a.i./kg dry weigh soil groups. There was a statistically significant reduction 

in mean number of juvenile earthworms found in the 101.7, 180.3, 312.3, and 573.2 mg a.i./kg 

dry weight soil groups when compared to the control. The 28-day NOAEC related to growth 

was 180.3 mg a.i./kg dry weight soil. The 56-day NOAEC related to reproduction was 57.8 mg 

a.i./kg dry weight soil. 

Additionally, there were no effects on the reproduction of the collembola species Folsomia 

candida at the highest concentration tested (MRID 48023625). There were also no effects on 

mortality and reproduction on the soil mite species Hypoaspis aculeifer (MRID 48023626). 

Degradates

The effect of penflufen-3-hydroxy-butyl, a transformation product of penflufen on the survival, 

growth and reproduction of earthworms, Eisenia fetida, was studied over an eight week (56 day) 

period (MRID 48023613; Supplemental). Adult earthworms were exposed in an artificial soil to 

application rates of 62.5, 125, 250, 500 and 1000 mg a.i./kg dry weight soil. After 28 days of 

exposure, no adverse behavioral and morphological effects, and no mortality were observed in 

the adult earthworms in any of the control or treatment groups. After eight weeks, there was no 

statistically significant difference in reproduction between the control and any of the treatment 

groups. The 28-day NOAEC related to growth was greater than 1000 mg a.i./kg dry weight soil. 

The 56-day NOAEC related to reproduction was greater than 1000 mg a.i./kg dry weight soil. 

The effect of penflufen-pyrazolyl-AAP, a transformation product of penflufen on the survival, 

growth and reproduction of earthworms, Eisenia fetida, was studied over an eight week (56 day) 

period (MRID 48023614; Supplemental). Adult earthworms were exposed in an artificial soil to 

application rates of 63, 125, 250, 500 and 1000 mg a.i./kg dry weight soil. The 28-day NOAEC 

related to growth was 1000 mg a.i./kg dry weight soil. The 56-day NOAEC, based on the 

statistically significant difference related to reproduction was 500 mg a.i./kg dry weight soil. 

There were no effects of the 3-hydroxy-butyl degradate on Folsomia candida (MRID 48023627) or 

Hypoaspis aculeifer (MRID 48023628) at the highest concentration tested. There were also no effects of 

the pyrazolyl-AAP on either species at the highest concentration tested (MRIDs 48023629 and48023630, 

respectively). 

3.3.2.4. Toxicity to Terrestrial Plants 

A limit study (MRID 48023601; Acceptable) was conducted to evaluate the phytotoxic effects of 

PEN 240FS on the vegetative vigor of non-target terrestrial plant species following a postemergence application of 0.22 lbs ai/A onto the foliage of plants at the 2-4 leaf stage. The plants 

of eleven species were tested, including seven dicotyledonous species: sugar beet (Beta 

vulgaris), oilseed rape (Brassica napus), cucumber (Cucumis sativus), buckwheat (Fagopyrum

esculentum), soybean (Glycine max), sunflower (Helianthus annuus) and tomato (Lycopersicon 

esculentum) plus four monocotyledonous species: oat (Avena sativa), onion (Allium cepa), 

ryegrass (Lolium perenne) and corn (Zea mays). 
-Page 56 of 115- 

After 21-days, survival for the eleven species tested was 97 to 100% for the control and 100% in 

the treated groups. No adverse phytotoxicity effects were observed in either the control or 

treatment groups. Inhibition of shoot dry weight for the eleven species tested ranged between -

16 and 2% in relation to the control. Oilseed rape and corn were the only species exhibiting a 

reduction in shoot dry weight; shoot dry weight inhibition was 2% for both oilseed rape and 

corn, respectively. Reductions in plant height for the eleven species tested ranged between -11 

and 5%. Tomato, onion, and oat were the only species exhibiting reductions in plant height of 1, 

1, and 5%, respectively, when compared to the controls. The EC25 for all plants is >0.22 lbs ai/A; 

the limit rate will be used in lieu of a NOAEC. 

A limit study (MRID 48023598; Acceptable) was to evaluate the effects of PEN 240 FS on the 

seedling emergence and seedling growth on non-target terrestrial plant species. PEN 240 FS was 

applied as a pre-emergence application on soil surface at an application rate of 0.22 lbs ai/A. 

Eleven species were tested, including seven dicotyledonous species: sugar beet (Beta vulgaris), 

oilseed rape (Brassica napus), cucumber (Cucumis sativus), buckwheat (Fagopyrum 

esculentum), soybean (Glycine max), sunflower (Helianthus annuus.) and tomato (Lycopersicon 

esculentum), and four monocotyledonous species: oat (Avena sativa), onion (Allium cepa), 

ryegrass (Lolium perenne) and corn (Zea mays). 

At test termination (21 days), seedling emergence for the 11 crop species ranged between 72.5 

and 100% in the untreated control group, and 62.5 to 97.5% in the treated group. Emergence 

was inhibited relative to control emergence only in oilseed rape, corn, and onion seedlings; 

percent inhibition in emergence was 11, 5, and 14% for oilseed rape, corn, and onion, 

respectively. Emergence in the other treated species was greater than the control emergence. 

Percent seedling survival for the 11 crops ranged from 97 to 100% in the control group and was 

100% in all treated groups. Pen 240 FS was not shown to have any negative effects on survival 

of emerged seedlings. Reductions in plant height for the eleven crops ranged from -10 to 5% 

between the controls and treated group. Soybean, tomato, onion, and ryegrass were the only 

species with reductions in plant height relative to the respective controls with reductions of 3, 5, 

4, and 1%, respectively. Reductions in shoot dry weight to the eleven crops ranged from -22 to 

13% between the controls and treated group. Oilseed rape, buckwheat, soybean, tomato, and 

onion were the only species with reductions in shoot dry weight relative to their respective 

controls with reductions of 5, 10, 12, 6, and 13%, respectively. The EC25 for all plants is >0.22 

lbs ai/A; the limit rate will be used in lieu of a NOAEC. 

 

No terrestrial plant studies were submitted for technical grade penflufen or the degradates. 

4. Risk Characterization 

4.1. Risk Estimation 

Toxicity data and exposure estimates are used to evaluate the potential for adverse ecological 

effects on non-target species. This screening-level assessment for penflufen relies on the 
-Page 57 of 115- 

deterministic RQ method to provide a metric of potential risks. The RQ provides a comparison 

of exposure estimates to toxicity endpoints (i.e., the estimated exposure concentrations are 

divided by acute and chronic toxicity values). The resulting unitless RQs are compared to the 

Agency’s LOCs, as shown in Table 2.3. LOCs are used by the Agency to indicate when the use 

of a pesticide, as directed by the label, has the potential to cause adverse effects to non-target 

organisms. 

 

4.1.1. Aquatic Organisms 

The highest screening-level aquatic EECs based on the maximum application rates for each 

proposed use pattern were used to derive RQs. These exposure estimates represent 

concentrations in surface water (Table 3.7). Peak EECs are used to represent acute exposure to 

fish, aquatic invertebrates, and aquatic plants, and the highest 21-day and 60-day average EECs 

represent chronic exposure to aquatic invertebrates and fish, respectively. Because of 

penflufen’s persistence, each subsequent year may be affected by the previous year’s application. 

The PRZM-EXAMS modeling demonstrates year-to year carry over for the first 20 years of 

modeling (see Figure 3.2). 

4.1.1.1. Fish and Invertebrates 

Fish 

Table 4.1 lists RQs calculated for fish (freshwater and estuarine/marine) and aquatic-phase 

amphibians exposed to penflufen, based on the acute EECs generated from PRZM/EXAMS and 

Tier I Rice Model modeling scenarios. Results of acute toxicity studies in freshwater and 

estuarine/marine fish (Table 3.13) indicate that penflufen is “highly toxic” to freshwater fish on 

an acute exposure basis. However, most RQs for proposed uses of penflufen fall below the 

Agency’s acute risk to listed species LOC (0.05), as well as the Agency’s acute risk to non-listed 

species LOC of 0.5. The RQ from the proposed rice is equal to the listed species LOC. No other 

scenarios exceed the LOCs. 

RQs for chronic exposures also fell below the Agency’s chronic risk to listed and non-listed 

species LOC (1.0). 
-Page 58 of 115- 

Table 4.1. Risk Quotients for Freshwater Fish and Aquatic-phase Amphibians 

Exposed to Penflufen at the Highest EECs Using the Most Sensitive of the Available 

Endpoints. 

Use 

 

EECs 

(ppb) 

Fish and Aquatic-phase Amphibian 

RQs 

LC50 = 90 μg ai/L 

NOAEC = 18.1 μg ai/L 

Peak 60-day Acute1,2 Chronic3

Potato 3.52 3.47 0.039 0.19 

1.13 1.07 0.014 0.06 

Beans and Peas 2.39 2.32 0.027 0.13 

Rice 4.71 <4.71 0.052 <0.26 1

 Acute risk to non-listed species LOC for aquatic fish is 0.5 

2

 Acute risk to listed species LOC for aquatic fish is 0.05 

3

 Chronic risk to listed and nonlisted aquatic animals is 1.0 

Aquatic Invertebrates 

Definitive acute toxicity endpoints from studies on the TGAI were unavailable for freshwater 

invertebrates and thus RQs were not calculated and risk is expected to be low as the EC50 is 

greater than the highest concentration tested. The relationship between the highest endpoints in 

the studies and the estimated exposure will be discussed in the Risk Description section. Based 

on all available acute studies, penflufen is categorized as moderately toxic to aquatic 

invertebrates. A definitive estuarine/marine endpoint is available for Eastern oyster (1300 μg 

ai/L), but the RQ is <0.01. A definitive chronic exposure toxicity endpoint is available for 

freshwater invertebrates and the RQ is <0.01, at least two orders of magnitude below the 

Agency’s level of concern (1.0). 

The 10- day NOAEC based on growth for benthic invertebrates through pore water exposure is 

780 μg ai/L. The RQ calculated with the maximum 21d pore water EEC (3.44 μg ai/L) is <0.01. 

Therefore, risk is assumed to be low. The relationship between the toxicity endpoints and the 

exposure estimates will be discussed further in the Risk Description section. 

4.1.1.2. Aquatic Plants 

Although penflufen does exhibit effects on both Lemna gibba and Pseudokirchneriella 

subcapitata, these effects are at much higher concentrations than those estimated for the highest 

proposed penflufen uses. For both taxa, both listed and nonlisted RQs are <0.01, while the 

LOCs are 1.0.

 4.1.2. Terrestrial Organisms 

4.1.2.1. Mammals 

 Acute RQs were not calculated for mammals because only non-definitive acute oral 

toxicity data are available. Based on the available acute toxicity data, no mortality was observed 

in any of the mammalian studies conducted on penflufen technical or its formulated products at 
-Page 59 of 115- 

the highest concentrations/doses tested; as such, penflufen is categorized “practically nontoxic” 

to mammals on an acute exposure basis. Further discussion of the predicted exposure values 

relative to the levels at which no mortality was observed is provided as part of the risk 

description in Section 4.2.4.

 

Based on the proposed maximum application rates, combined with the amount of seed per acre, 

the highest exposures occurred for the canola and alfalfa uses, resulting in the highest chronic 

RQs across all uses of 0.14, less than the chronic risk LOC of 1.0. Even adding the in-furrow 

treatment to the seed piece treatment, the chronic exposure RQ for the potato use is 0.04. Table 

4.2 lists maximum chronic exposure mammal RQs for all of the proposed uses based on the 

upper 90th percentile Kenaga values. These RQs all fall below the Agency’s mammalian chronic 

risk to listed and non-listed species chronic risk LOC (1.0). 

Table 4.2. Chronic Mammalian Risk Quotients for Penflufen Proposed Uses

Crop 

Penflufen 

application 

rate 

(lbs. a.i./A) 

Maximum 

Seeding Rate 

(lbs 

seed/acre)1

Maximum 

Seed 

Application 

Rate (mg 

ai/kg seed) 

Mammalian Dose 

(mg ai/kg-bw/day) Mammalian RQs 

Alfalfa 0.00225 15 141.82 30.05 0.14 

Bean3 0.0384 436 47.27 10.02 0.05 

Canola 0.00123 15 141.82 30.05 0.14 

Corn 0.0033 33 94.55 20.03 0.09 

Cotton 0.0019 19 94.55 20.03 0.09 

Potato 0.13 6969 19.20 4.07 0.02 

Potato2 0.28 6969 38.41 8.14 0.04 

Rice 0.006 129 47.27 10.02 0.05 

Sunflower 0.00123 4 141.82 30.05 0.14 

Wheat 0.0078 156 47.27 10.02 0.05 1

 USEPA, 2011a, Acres Planted per Day and Seeding Rates of Crops Grown in the United States, Memorandum from Beck and 

Ratnayake, Biological and Economic Analysis Division, to Deschamp (HED) and Spatz (EFED), March 2011. 2

Including the in-furrow treatment 

3

Succluent beans have the highest seeding rate, therefore present the greatest exposure

4.1.2.2. Birds 

Acute RQs were not calculated for birds because only non-definitive acute and sub-acute toxicity 

endpoints are available. Penflufen is categorized as practically non-toxic to canary, mallard duck 

and bobwhite quail on an acute and subacute oral and dietary basis. Treatment-related sublethal 

effects were observed in mallard duck and bobwhite quail studies at the highest concentrations 

tested; however these concentrations were above the typical limit dose for avian acute and subacute dietary toxicity studies. These effects (noted previously) will be discussed further, relative 

to potential exposure, in the Risk Description section, but acute risk to avian species is expected 

to be low. 

 
-Page 60 of 115- 

The measure of effect for chronic risk to birds was a non-definitive endpoint (NOAEC <292 mg 

a.i./kg-diet. Therefore, chronic RQs for birds are not calculated. The nondefinitive endpoint 

relevant EECs are discussed qualitatively in the Risk Description section. 

4.1.2.3. Terrestrial Invertebrates 

Risk assessments are not conducted for terrestrial invertebrates at the screening-level at this time. 

Characterization of exposure relative to known toxicity endpoints for terrestrial invertebrates will 

be discussed in the Risk Description section. 

4.1.2.4. Non-target Terrestrial Plants 

Potential effects to riparian and upland vegetation are assessed deriving RQs from terrestrial 

plant seedling emergence and vegetative vigor EC25 and NOEAC endpoints. Based on the 

results of the submitted terrestrial plant toxicity tests for the typical formulated product Penflufen 

240FS, there were no effects reported at the highest rate tested (0.22 lbs ai/A). Based on the runoff exposure calculations in TerrPlant, using the greatest per acre rate from the potato use (0.28 

lbs ai/A; 0.14 lbs ai/A for pieces plus 0.14 lbs ai/A), both nonlisted and list plant RQs are <0.01 

for dry areas and 0.25 for low-lying areas vulnerable to run-off, well below the LOC of 1.0. 

Therefore, risks to terrestrial plants from the proposed uses of penflufen are expected to be low. 

4.2. Risk Description 

The results of risk estimation indicate that proposed uses of penflufen are unlikely to adversely 

affect non-listed fish or aquatic invertebrates or aquatic plants on either an acute or chronic 

exposure basis. Similarly, with the exception of assumed risk to birds from chronic exposure, 

terrestrial animal and plant risks appear to be below the Agency’s levels of concern. Therefore, 

the risk hypothesis for this risk assessment is only partially supported (risk from chronic 

exposure is presumed for birds). 

4.2.1 Exposure to Aquatic Organisms 

Surface water EECs resulting from applications of seeds treated with penflufen for potato and 

bean uses are conservative estimates of exposure for the proposed uses of penflufen as a seed 

treatment fungicide. Application rates were calculated based on the best available data for 

seeding rates for particular uses, which may result in low relative pounds of active ingredient 

applied on a per acre basis. The potato seed piece application was modeled as an incorporated 

application where seed pieces are planted at a depth of 3-6 inches (USDA, 2000); an additional 

in-furrow spray was made at the time of planting, also at a depth of 3-6 inches (the combined 

modeled application rate, 0.28 lbs a.i./A, was used as an input for PRZM). The bean/legume use 

represents the realm of penflufen seed treatments for crops that are seeded at the surface, where 

the potato use represents crops that are seeded below the surface. 

The Tier I Rice model was used to estimate exposure from rice seed treated with penflufen. The 

EECs resulted in an RQ >0.05 for listed fish, which is an exceendence for listed fish. The label 
-Page 61 of 115- 

proposes the application of treated seed to dry fields, however the exact planting method is not 

specified, nor is water holding times. Information on the holding times for paddy water, and 

permitted planting methods (e.g., drilling) would better inform the risk assessment for the rice 

use. The model estimate is a conservative estimate of exposure, considering the Tier I Rice 

Model assumes that when a pesticide is applied to a rice paddy it instantaneously partitions 

between the water phase and the sediment phase. The model does not account for pesticide 

degradation, mass transfer between the aqueous phase and the sediment, volatilization, dilution, 

or other dissipation processes; therefore the model provides an upper bound estimate of exposure 

for penflufen which is proposed for use on rice as a dry seeded application. Further, for 

modeling purposes we assumed that 100% of the chemical on the seed coat is available. It is 

possible that only a percentage of the chemical on the seed coat is available and will partition 

from the sediment to the water column. It is unknown what the available percentage is, but this 

uncertainty could be addressed with the submission of additional data supporting the release rate 

of penflufen from the seed coat into the soil (i.e., partitioning from the seed coat). Also there 

will be some amount of the chemical that is taken up by the plant during emergence, and some 

amount that is degraded prior to, and during, the flooded phase of rice production. These 

information may help to mitigate the potential risk to listed fish resulting from the use of 

penflufen. 

Another potential mitigating action is a reduction in the application rate for rice seed from 0.006 

lb a.i./A to 0.005 lb a.i./A reduces the peak exposure value from 4.71 to 3.93 ug/L, which results 

in no acute risk LOC exceedance. 

Model uncertainties are discussed in greater detail in Section 4.3. 

4.2.2 Risks to Aquatic Animals 

Freshwater Fish 

For acute exposure studies were submitted to the Agency for penflufen TGAI, as well as one for 

each of the two primary degradates. Studies on penflufen-3-hydroxy-butyl and penflufen 

pyrazolyl-AAP were conducted using common carp, the species most acutely sensitive to the 

TGAI. The toxicity endpoints derived in these studies are much less sensitive than any from the 

TGAI studies. Additionally, there is a study, also with the common carp, that was conducted 

using the PEN 240FS product (a single ai formulation). This study resulted in an endpoint 

similar to the TGAI study (0.101 μg ai/L vs 0.090 μg ai/L), indicating that inert ingredients in 

the formulation do not enhance penflufen’s toxicity to fish. 

The most sensitive endpoint derived from the available studies was compared to the highest 

expected aquatic exposure values, and almost all are below the Agency’s levels of concern. 

Common carp was the most sensitive species to penflufen among those studied, with an LC50 of 

0.090 μg ai/L, and resulted in an RQ equal to the listed species LOC. The other freshwater fish 

tested, rainbow trout, bluegill sunfish and fathead minnow, although apparently less sensitive, 

were within an order of 4X of the carp and so the range in sensitivity appears to be quite narrow. 
-Page 62 of 115- 

However, the sheepshead minnow was quite a bit less sensitive to penflufen with an LC50 of 

1150 μg ai/L. Therefore, risk to estuarine/marine fish is generally expected to be low. 

The RQ for acute exposure to freshwater fish from the proposed rice use is 0.052, indicating the 

potential for risk to listed freshwater fish from this use (LOC for listed species is 0.05). There is 

uncertainty in the exposure value for this use, as described above. However, a reduction in 

application rate from 0.006 lbs ai/A to 0.005 lbs ai/A would reduce the RQ to 0.044, below the 

listed species acute risk LOC. 

The EECs derived from PRZM/EXAMS are selected from the 30-year modeling scenario. 

However, the ecological pond modeled with EXAMS is a static water body of fixed volume and 

no outlet. Penflufen is persistent and since the ecological pond has no outlet, the modeling 

indicates penflufen accumulates in the pond throughout the 30-year simulations. EECs from 

flowing water bodies may be less than those estimated in the static pond. Exposure endpoints in 

this assessment are based on yearly peak concentrations from the static pond, per USEPA 

modeling guidance for ecological risk assessment (USEPA, 2004). In the case of persistent 

compounds, a 1-in-10 year EEC does not only reflect varying meteorological conditions that are 

expected once every 10 years, since material carries over from year to year. Figure 3.2 shows 

that there is a buildup of the compound over the first 20+ years of application, due to penflufen’s 

persistence. 

Although there is a definitive endpoint for chronic exposure to freshwater fish from a study with 

fathead minnow, fathead minnow is not quite as acutely sensitive to penflufen as the common 

carp. Therefore, an acute to chronic ratio (ACR) from the fathead minnow studies (5X) was 

applied to the common carp. The chronic RQ for the rice use, which results in the highest 

estimated exposure, is 0.26, only about a quarter of the Agency’s level of concern. 

Based on a water column exposure study, penflufen is not expected to bioaccumulate in fish. 

Due to its low log Kow (3.3), penflufen is not expected to bioaccumulate in aquatic invertebrates 

or bioaccumulate up the food chain (confirmation with the model KABAM is not shown). 

Aquatic Invertebrates 

Acute RQs were not calculated for freshwater invertebrates due to the non-definitive endpoint 

for daphnid (>4660 μg total ai/L), crayfish (>4500 μg ai/L) and for the benthic chironomid 

(>8280 μg ai/L). RQ-values calculated with the highest concentration tested in these studies 

result in RQs <0.01, and there is no way to know from these studies how much greater than the 

highest dose test the concentration would need to be to achieve a definitive LC50 value. 

Sublethal effects were noted in the daphnid study at the highest dose tested, making the observed 

NOAEC 2.33 mg ai/L The highest RQ-value calculated using that concentration would be 

0.001, more than two orders of magnitude below the listed species LOC of 0.05. 

The estuarine/marine invertebrates, mysid shrimp and Eastern oyster studies also reported 

sublethal effects at the higher concentrations. Using the observed NOAECs (440 and 1440 μg 

ai/L, respectively), the highest RQ-value would be 0.01, 5X lower than the listed species acute 
-Page 63 of 115- 

risk LOC. 

Chronic risk to freshwater invertebrates was assessed based on one reproductive study on 

Daphna magna; the actual highest RQ is 0.003 several orders of magnitude below the Agency’s 

chronic risk LOC of 1.0. However, estuarine/marine invertebrates exhibited slightly greater 

sensitivity to penflufen than daphnids on an acute exposure basis. Because the daphnid acute 

value is nondefinitive, an ACR cannot be used to estimate the potential for effects from 

penflufen on a chronic exposure basis. But, the mysid NOAEC would need to be several orders 

of magnitude lower than the daphnid NOAEC for there to be an exceedance of the LOC. 

While the benthic chironomid NOAEC, based on pore water concentration, was greater than 780 

μg ai/L, based on growth. This value results in an RQ-value of 0.004, several orders of 

magnitude below the current LOC for benthic organisms of 1.0. The RQ-value was calculated 

using the 1-in-10-year 21-day pore water concentrations from PRZM/EXAMS, although the 

study was only of a 10-day duration. Because penflufen’s concentrations do not change much 

between the peak and the 60-day values, risk to benthic invertebrates is expected to be low 

regardless of which value is considered. 

Based on the 40 CFR Part 158 data requirements, penflufen should have a chronic sediment 

toxicity study submitted, since the half-life is greater than 10 days. The absence of this study 

introduces uncertainty as to the long-term effect of penflufen on sediment dwelling invertebrates. 

Given the metabolism half lives of up to 866 days, multiple years of penflufen application would 

result in increasingly high levels of exposure to these organisms. However, as indicated above, 

the NOAEC for growth in the 10-day study is several orders of magnitude below the LOC. 

While the absence of this study represents an uncertainty in the risk assessment, requiring these 

data are unlikely to affect the risk conclusions for the proposed uses. 

4.2.3 Risks to Aquatic Plants 

Based on the available information on Lemna gibba and Pseudokirchneriella subcapitata, the 

proposed uses of penflufen do not exceed the Agency’s LOC for aquatic plant (1.0) for nonlisted 

or listed plants. While RQs were not calculated in the Risk Estimation section due to the lack of 

definitive IC50 values, there were effects noted in the studies. The lowest NOAEC among the 

vascular and nonvascular studies involving the TGAI or formulation is 520 μg ai/L for green 

algae (based on biomass and cell density). At that concentration, the RQ = 0.006 whereas the 

LOC is 1.0. Therefore, potential risk to aquatic plants from the proposed uses of penflufen is 

expected to be low. 

However, risk to aquatic nonvascular species is typically evaluated with not only the green algae 

that was submitted, but also with a cyanobacteria, a centric diatom and a pinnate diatom. These 

additional species have not been submitted and are an appreciable source of uncertainty in the 

risk assessment. These planktonic taxa form the very basis of the aquatic food web and are 

frequently more sensitive to pesticides than green algae. However, any of these species would 

need to have a NOAEC of 3 μg ai/L to exceed the listed species LOC. Given that the green 

algae NOAEC is 520 μg ai/L, this would seem unlikely. For sedaxane, also a pyrazole 
-Page 64 of 115- 

carboximide, the NOAEC for green algae is 990 μg ai/L. The next most sensitive nonvascular 

plant species, the diatom Navicula pellicosa, has a NOAEC of 1200 μg ai/L. 

In addition to studies on TGAI and the PEN 24FS formulation, degradate studies with green 

algae were submitted. Green alga was shown to be more sensitive to penflufen-pyrazolyl-AAP 

and penflufen -3-hydroxy-butyl than to the parent. However, even if the degradates were present 

in the water column at 100% of the parent, the highest RQ-value (based on the penflufenpyrazolyl-AAP NOAEC of 98.3 μg ai/L) would be 0.03, well below the listed species LOC of 

1.0. 

4.2.4. Risks to Mammals 

Acute RQs were not derived for mammals in the Risk Estimation section of this assessment 

because no mortality to rats was observed at the highest treatment level in the acute oral 

mammalian study (i.e. >2000 mg ai/kg-bw) of penflufen technical. Based on the seed treatment 

calculations in T-REX and the highest dose tested in the acute rat study, the highest RQ-value for 

15 gram mammals is 0.04 for potatoes with treated seed pieces plus the in-furrow treatment for 

the PEN 240FS product, which results in the highest exposure estimates for penflufen. Given 

that the 15 gram mammal is considered the most vulnerable and the RQ-value is less than half 

the listed species LOC (0.1), the potential for risk to mammals from acute exposure appears to be 

low. 

 

As presented in the Risk Estimation, chronic mammalian RQs for all applications of penflufen 

fell below the Agency’s risk to listed and nonlisted species LOC of 1.0, with a calculated 

maximum RQ of 0.14 for the proposed canola and sunflower uses. 

Based on results of the screening model SIP, drinking water exposure alone is not a concern for 

mammals. Penflufen has a relatively low solubility in water, which is the only parameter used in 

estimating potential exposure, and mammals are not particularly sensitive to penflufen on either 

an acute or chronic basis. 

4.2.5. Risk to Birds 

 

Because the LD50 and LC50 values exceeded the highest treatment levels tested in the submitted 

acute oral and sub-acute dietary avian studies, standard RQs for acute and sub-acute exposure 

were not calculated in the Risk Estimation section of this assessment. However, sublethal effects 

were observed on female body weights in the acute oral study with bobwhite quail at the highest 

dose tested (NOAEC=2000 mg ai/kg-bw). The maximum acute exposure RQ-value for a 20 

gram bird (considered the most vulnerable in T-REX) is calculated from the proposed potato 

seed piece plus in-furrow treatment is 0.13, greater than the listed species LOC of 0.1. However, 

this number reflects the bobwhite NOAEC and the canary nondefinitive LD50 value, and not the 

median lethal dose for either species. Additionally, potato seed pieces (and the in-furrow 

treatment) are covered with at least 3” of soil, reducing potential exposure appreciably. The next 

highest RQ-value is for the proposed bean use, 0.01. Therefore, while the calculated RQ-value is 

<0.13, acute risk to avian species from the proposed uses is considered to be low. 
-Page 65 of 115- 

Chronic RQs were derived as a screening exercise in the Risk Estimation section of this 

assessment for the non-definitive risk measure of effect to birds (NOAEC < 292 mg ai/kg-diet). 

As a minimum level of risk, none of the RQs for any proposed uses of penflufen exceeded the 

Agency’s chronic risk to birds LOC of 1.0. The highest RQ-value (0.49) is for the proposed 

canola and sunflower uses. However, the maximum direct chronic risk to nonlisted and listed 

bird species is unknown and cannot be precluded with the available data. The study from which 

this endpoint is derived was conducted on mallard duck over ca. 22 weeks based on reduction in 

percent hatch per live embryo (9% at the lowest concentration), which is a frank effect with 

direct implication for the reproductive success of avian species. No effects were observed in the 

bobwhite quail reproduction study. Based on the calculated RQ-value using the LOAEC in the 

mallard study, the mallard would need to be twice as sensitive to penflufen (i.e. the NOAEC 

would need to be half the LOAEC) for the chronic LOC to be exceeded. The next highest RQvalues (corn and cotton; 0.32) indicate the NOAEC would need to be 3X lower for there to be an 

exceedance. However, direct chronic risk to listed and nonlisted avian species cannot be 

precluded and is presumed for proposed uses of penflufen. A second study on reproductive 

effects in mallard duck in which a definitive NOAEC is derived would greatly reduce uncertainty 

in making a chronic risk call to birds. 

 

The potential for direct mortality of nonlisted and listed birds (and to terrestrial-phase amphibian 

and reptiles for which birds serve as surrogates) from acute and subacute exposures of penflufen 

for all proposed uses is not expected. Direct risk is presumed for nonlisted and listed birds and 

surrogates from chronic exposures to all proposed uses and application methods of penflufen. 

Based on results of the screening model SIP, drinking water exposure alone is not a concern for 

birds. Penflufen has a relatively low solubility in water, which is the only parameter used in 

estimating potential exposure, and birds are not particularly sensitive to penflufen on either an 

acute or chronic basis. However, there is not a NOAEC available for mallard duck (as discussed 

previously), and so risk to birds from drinking water alone is presumed. However, the mallard 

duck NOAEC would need to be half of the lowest rate tested in the available study for drinking 

water exposure alone to be a route of concern. 

4.2.6. Potential Effects on Terrestrial Invertebrates 

The available toxicity data for honey bees indicate that direct contact and oral exposure to 

penflufen is not likely to adversely affect honey bee pollinators (young adult forage bees) in and 

around proposed use areas for penflufen. There is uncertainty in the amount of exposure that 

honey bees would be subject to from the proposed uses, but the lack of effects at 100 μg ai/ bee 

is expected to account for some, if not all, uncertainty in exposure. However, penflufen is coformulated in two products with clothianidin (PC Codes 044309 (stereochemistry unspecified); 

660108 (E-isomer)), a systemic neonicotinic insecticide that is associated with high bee toxicity 

and reported incidents with honey bees. Some of the incidents reported for clothianidin are 

associated with dust from abraded seed coats from drilled seed applications (USEPA 2011). 

There are no available data on the effect of this coformulation on honey bees. 
-Page 66 of 115- 

Mortality in parasitoid wasps was negligible, however effects on reproduction were observed at 

all concentrations. Percent reduction relative to the control was roughly 60% between 0.026 lbs 

ai/A and 0.22 lbs ai/A. At 0.013 lbs ai/A the reduction was 18%. Although the degree to which 

these species are likely to be exposed to penflufen is uncertain, and mortality does not appear to 

be an issue at the highest proposed rates, reproduction of these species may be affected at some 

of the higher proposed rates. However, while the maximum proposed per acre rate is 0.28 lbs 

ai/A, the majority of applications are 0.04 lbs ai/A or less. Again, being co-formulated with 

clothianidin should pose a greater potential for effects on to beneficial insects than penflufen 

alone. 

Affects to body weight were observed in earthworms from a 14-day study at concentrations of 

562 and 1000 mg a.i./kg dw soil. Reproductive effects, i.e. number of offspring produced, were 

observed in a 56-day study at concentrations of as low as 101.7 mg a.i./kg dw soil (NOAEC 57.8 

mg ai/kg soil). Given that penflufen is proposed as a seed treatment, the degree of exposure to 

earthworms is uncertain. The most likely exposure scenario is the potato seed piece with the infurrow treatment. But even this proposed use covers a relatively small percentage of the field. 

As an exercise to characterize this toxicity at relevant environmental concentrations, an estimate 

was made as to the expected concentration of penflufen in soil at the maximum single 

application rate of 0.22 lbs a.i./A, assuming a soil depth of 15 cm and bulk density of 1.3 g/cm3. 

Given this scenario, although rough, the predicted maximum soil concentration of penflufen 

would be 0.128 mg a.i./kg dw soil, which is orders of magnitude lower than the most sensitive 

effects endpoint from earthworm toxicity studies (57.8 mg a.i./kg dw soil). Therefore, the 

potential for direct risk to earthworms from exposure to penflufen in soil is not expected. 

Screening-level risk assessments do not typically evaluate risks to terrestrial invertebrates; 

however, toxicity information for beneficial insects is used to develop precautionary label 

language where necessary. Based on the available data, precautionary label language for bees 

does not appear necessary for end-use products with penflufen as the only active ingredient. 

4.2.7. Risk to Terrestrial Non-target Plants 

Limit tests were submitted for both vegetative vigor and seedling emergence, at the rate of 0.22 

lbs ai/A. No effects >25% were observed in either study. Minimal measured inhibitions were 

observed in biomass and shoot length, up to 5% in the vegetative vigor study, none statistically 

significant. In the seedling emergence study, measured inhibition of 14% emergence was 

observed in onion and 10% and 12% biomass in buckwheat and soybean, respectively, none 

statistically significant. For the purpose of this risk assessment, the limit rate of 0.22 lbs ai/A is 

used in lieu of a NOAEC. The highest per acre application rate of 0.28 lbs ai/A results in a listed 

species RQ of 0.25 for low lying areas vulnerable to run off and <0.1 for higher areas. Although 

the limit studies did not test up to the highest per acre application rate, this rate is for the potato 

seed piece plus in-furrow treatment, which is an incorporated application. The RQ of 0.25 

represents the rate of 0.28 lbs ai/A unincorporated. Applying an incorporation depth of 3” 

reduced the RQ to 0.13. The 0.28 lbs ai/A application rate is an order of magnitude greater than 

the per acre rate for any other proposed use. 
-Page 67 of 115- 

Because all the proposed uses are seed treatments, no drift exposure is expected to nontarget 

plants. The in-furrow application is generally sprayed extremely close to the soil and the 

application is immediately covered. Usually the nozzle is shielded to protect it from the soil. 

However, even if a 1% spray drift assumption is applied, the highest RQ is 0.13 for spray drift 

and 0.38 for low lying areas vulnerable to runoff. 

While there is uncertainty due to the observed inhibitions in study endpoints, exacerbated by the 

study not being conducted up to the maximum per acre application rate, potential risk to 

nontarget terrestrial plants is expected to be low. The need for additional data for this risk 

assessment thought to have minimal on the risk conclusions in this risk assessment. 

4.3. Uncertainties and Data Gaps 

4.3.1. Fate and Transport 

There is considerable variability in the aerobic degradation rate, contributing to the uncertainty 

of the degradation rate of penflufen. Two studies were submitted that encompass six soils to 

fulfill the aerobic soil metabolism data requirement for the parent penflufen (OPPTS 835.4100) 

for all outdoor pesticides use. Both studies were classified as Supplemental for various scientific 

reasons (e.g., study duration was insufficient to characterize the degradation of the parent, 

formation and decline of major degradates was not well characterized, half-lives were 

extrapolated beyond the study duration). Additional acceptable studies, or supplemental data 

addressing the scientific issues identified in the studies would help reduce the uncertainty in the 

study results. Further uncertainty regarding the half-lives of penflufen and its degradates would 

be reduced with additional studies conducted for a sufficient duration to accurately characterize 

the formation and decline of all major degradates. 

There was significant variability in the reported data for the aerobic aquatic metabolism study; 

the Anglerweiher water:sand system reported an uncharacterized decline of the parent and major 

degradates. This system was not be used for risk assessment purposes since the half-lives are of 

uncertain value. Therefore for modeling purposes the single half-life from the Hoeniger 

water:sediment system was multiplied by three to account for the potential variability in 

degradation between aquatic systems. Additional data for another water:sediment system would 

reduce the uncertainty and may reduce model input values. 

4.3.2. Effects Uncertainties 

There are no chronic exposure toxicity data on common carp, the most acutely sensitive fish 

species. Therefore, an ACR was applied to common carp based on the fathead minnow, for 

which there are both acute and chronic toxicity data. The ACR is considered protective of fish 

for the purpose of this risk assessment; however, the application of an ACR in the absence of 

actual data does introduce uncertainty to the risk assessment. 

For the purpose of this risk assessment, the per acre in-furrow application was considered 

additive to the per acre potato seed piece application rate. While the nature of this application 
-Page 68 of 115- 

results in the total application to be covered by soil, the actual exposure to species that forage on 

potato seed pieces may be higher than estimated. Birds and mammals likely to forage on buried 

potato seed pieces are likely to be larger animals that would fall into the fruit/pods/seeds/large 

insect forage category, one of the less sensitive categories in the TREX model. However, this 

still represents an uncertainty in the assessment. 

As discussed previously, there is uncertainty regarding potential effects from chronic exposure to 

birds due to the lack of a NOAEC in one of the available avian reproduction studies. There was 

a statistically significant 9% reduction in the ratio of hatchlings to live embryos at the lowest 

concentration tested. It is unknown at what concentration a there would be no significant effect 

and so risk is presumed. The NOAEC would need to be half of the LOAEC (292 mg ai/kg-diet) 

for there to be an RQ exceedance for chronic exposure to birds. Other pyrazole compounds such 

as penthiopyrad (NOAEC =1520 mg ai/kg-diet) and pyroxasulfone (NOAEC=60 mg ai/kg-diet) 

do not show any consistency in toxicity from chronic exposure to birds. 

Degradate Toxicity 

Toxicity of the major degradates penflufen-3-hydoxy-butyl and penflufen-pyrazolyl-AAP are 

available for multiple taxa (fish, aquatic plants, earthworms) and in all cases were found to be 

less toxic than parent penflufen. The degree to which these toxicity studies are applicable to 

other taxa is an uncertainty in the risk assessment. However, given that fish are the most 

sensitive taxa to the parent, this risk assessment assumes that these degradates are equally less 

toxic than the parent across all taxa. 

No toxicity data on the degradate penflufen fluoro-acid are available. The lack of such data 

represents an uncertainty in the risk assessment. However, as it only forms from photolysis, 

exposure to this degradate is expected to be minimal. 

4.3.3. Aquatic Exposure 

Uses on potatoes and beans were simulated in the environment as granular applications, based on 

the assumption that seed, or seed piece, is treated with penflufen prior to planting (potato), or 

broadcasting seed on the surface of the soil (beans and peas, canola, etc.). Draft guidance for 

Recommended Input Parameter for Simulating Various Pesticide Application Practices (USEPA, 

2011a) instructs the model user to increase the application efficiency in PRZM to 1.0, and reduce 

the drift to 0.0 for granular applications. This is again based on the assumption that penflufen is 

adsorbed to the seed prior to planting and does not drift as dust or in a slurry. To the extent that 

actual use patterns and amount of treated seed differ from the modeling assumptions, actual 

environmental concentrations could be lower, and additional non-target organisms could be 

exposed to penflufen (e.g., if drift is a factor). EFED used the best available data to make a 

reasonably conservative estimate of the amount of crop that could receive applications of 

penflufen based on current seeding rates for the crops modeled. 

For the rice seed treatment, the label proposes the application of treated seed to a dry fields; 

however the planting method (e.g., drilling vs. broadcast) and water holding times are not 
-Page 69 of 115- 

specified on the label. Information on the holding times for paddy water, and permitted planting 

methods would better inform the risk assessment for the rice use. The model estimate is a 

conservative estimate of exposure, considering the Tier I Rice Model assumes when a pesticide 

is applied to a rice paddy it will instantaneously partition between a water phase and a sediment 

phase. The model does not account for pesticide degradation, mass transfer between the aqueous 

phase and the sediment, volatilization, dilution, or other dissipation processes; therefore the 

model provides an upper bound estimate of exposure for penflufen. Further, for modeling 

purposes we assumed that 100% of the chemical on the seed coat is available. It is likely that 

only a percentage of the chemical on the seed coat is available and will partition from the 

sediment to the water column. Also there will be some amount of the chemical that is taken up 

by the plant during emergence, and some amount that is degraded prior to and during the flooded 

phase of rice production. 

There is also uncertainty associated with the ability of the aquatic exposure modeling to simulate 

aquatic exposures as well as with the selection of input parameters. In this regard, one of the 

potentially important parameters that can impact concentration estimates is the selection of 

appropriate application dates. Although the pesticide application dates were selected to be most 

appropriate with considerations for labeled application recommendations (e.g., at the time of 

planting), model simulated cropping dates, and label restrictions, variability nevertheless results 

because the time span that a pesticide may be applied may be large and the actual application 

dates are unknown, or vary for different regions of the country. Such variability is caused by the 

temporal proximity of a pesticide application to rain events. As with all model estimates, the 

values presented here should not be viewed as precise estimates. 

5. Federally Threatened and Endangered (Listed) Species Concerns 

Section 7 of the Endangered Species Act, 16 U.S.C. Section 1536(a)(2), requires all federal 

agencies to consult with the National Marine Fisheries Service (NMFS) for marine and 

anadromous listed species, and/or the United States Fish and Wildlife Service (USFWS) for 

listed wildlife and freshwater organisms, if they are proposing an "action" that may affect listed 

species or their designated critical habitat. Each federal agency is required under the Act to 

ensure that any action they authorize, fund, or carry out is not likely to jeopardize the continued 

existence of a listed species or result in the destruction or adverse modification of designated 

critical habitat. To jeopardize the continued existence of a listed species means "to engage in an 

action that reasonably would be expected, directly or indirectly, to reduce appreciably the 

likelihood of both the survival and recovery of a listed species in the wild by reducing the 

reproduction, numbers, or distribution of the species" (50 C.F.R. § 402.02). 

To facilitate compliance with the requirements of the Endangered Species Act (subsection 

(a)(2)), the Office of Pesticide Programs has established procedures to evaluate whether a 

proposed registration action may directly or indirectly appreciably reduce the likelihood of both 

the survival and recovery of a listed species in the wild by reducing the reproduction, numbers, 

or distribution of any listed species (USEPA, 2004). After the Agency’s screening level risk 

assessment is conducted, if any of the Agency’s listed species’ LOCs are exceeded for either 

direct or indirect effects, an analysis is conducted to determine if any listed or candidate species 
-Page 70 of 115- 

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 new registration of penflufen on agricultural 

use sites it is expected that its use could occur nationwide. 

5.1. Action Area 

For listed species assessment purposes, the action area is considered to be the area affected 

directly or indirectly by penflufen use and not merely the immediate area where penflufen is 

applied. At the initial baseline, 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 listed terrestrial plants and wildlife are 

assumed to be located on or adjacent to the treated site and listed 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 3.1 of this risk assessment presents the proposed pesticide use sites 

that are used to establish initial co-location of species with treatment areas.

 5.2. Taxonomic Groups Potentially at Risk 

 

If the assumptions associated with the baseline 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, and the conceptual models addressing proposed new 

penflufen uses, and the associated exposure and effects analyses conducted for the penflufen 

baseline risk assessment are in Sections 2 to 3. The assessment endpoints used in the baseline 

risk assessment include those defined operationally as reduced survival and reproductive 
-Page 71 of 115- 

impairment for both aquatic and terrestrial animal species and survival, reproduction, and growth 

of aquatic and terrestrial plant species from both direct acute and chronic exposures. These 

assessment endpoints are intended to address the standard set forth in the Endangered Species 

Act requiring federal agencies to ensure that any action they authorize does not appreciably 

reduce the likelihood of both the survival and recovery of a listed species in the wild by reducing 

the reproduction, numbers, or distribution of the species. Risk estimates (RQs) which, 

integrating exposure and effects, are calculated for broad based taxonomic groups in the 

screening-level risk assessment presented in Section 4.

Both acute endangered species and chronic risk LOCs are considered in the baseline risk 

assessment to identify direct and indirect effects to taxa of listed species. This section identifies 

direct effect concerns, by taxa that are triggered by exceeding endangered LOCs in the baseline 

risk assessment, with an evaluation of the potential probability of individual effects for exposures 

that may occur at the established endangered species LOC. Data on exposure and effects 

collected under field and laboratory conditions are evaluated to make determinations on the 

predictive utility of the direct effect screening assessment findings to listed species. For 

penflufen, risk from chronic exposure is presumed for birds, reptiles and terrestrial-phase 

amphibians. Potential acute risk to listed fish and aquatic-phase amphibians is indicated based 

on marginal exceedance of the LOC. 

Table 5.1. Potential Effects to Federally Listed Taxa Associated with Direct or Indirect 

Effects from the Proposed New Uses of Penflufen. 

Listed Taxon Direct Effects Indirect Effectsa

Terrestrial and semi-aquatic plants - monocots No Yes

Terrestrial and semi-aquatic plants - dicots No Yes

Birds Yes Yes

Terrestrial-phase amphibians and reptiles Yes Yes

Mammals No Yes

Aquatic nonvascular plants No Yes

Aquatic vascular plants No Yes

Freshwater fish Yes Yes

Aquatic-phase amphibians Yes Yes

Freshwater crustaceans No Yes

Mollusks No Yes

Marine/estuarine fish No Yes

Marine/estuarine invertebrates No Yes a

until an endangered species assessment is complete, indirect effects to all species cannot be precluded 
-Page 72 of 115- 

 5.2.1. Probit Dose-Response Analysis 

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

information on the potential for acute direct effects to aquatic and terrestrial animals (USEPA, 

2004). As part of this evaluation, the acute RQ for listed species is presented in terms of the 

chance of an individual event (i.e., mortality or immobilization) should exposure at the EEC 

actually occur for a species with sensitivity to penflufen on par with the acute toxicity endpoint 

selected for RQ calculation. To accomplish this interpretation, the Agency uses the slope of the 

dose-response relationship available from the toxicity study used to establish the acute toxicity 

measures of effect for each taxonomic group that is relevant to this assessment. The individual 

effects probability associated with the acute RQ is based on the mean estimate of the slope and 

an assumption of a probit dose-response relationship. In addition to a single effects probability 

estimate based on the mean, upper and lower estimates of the effects probability are also 

provided to account for variance in the slope, if available. Based on the available acute toxicity 

for penflufen, a summary of the probit dose-response analysis is provided in Table 5.2. If no 

dose response information is available to estimate a slope for this analysis, a default slope 

assumption of 4.5 (with lower and upper bounds of 2 to 9) (Urban and Cook, 1986) is used. 

Individual effect probabilities are calculated based on an Excel spreadsheet tool IECV1.1 

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

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

the mean slope estimate (and the 95% confidence bounds of that estimate) as the slope parameter 

for the spreadsheet. The desired threshold for the probability of an individual effect is entered as 

the listed species LOC. In addition, the probability of an individual effect is also derived based 

on the calculated acute RQ, if available. 

Table 5.2. Summary of Penflufen Probit Dose Response Analysis for Listed Species 

Taxa (study type) Acute Effect 

Slope (95% C.I.) 

Chance of Individual 

Effect at Listed Species 

LOC (95% C.I.) 

Chance of Individual 

Effect at Derived Acute 

RQ1,2, (95% C.I.) 

Bird oral dose No mortality observed 1 in 2.9E+05 

(1 in 44 to 1 in 8.86E+18) 

Not calculated; no 

mortality observed

Bird dietary No mortality observed 1 in 2.9E+05 

(1 in 44 to 1 in 8.86E+18)

Not calculated; no 

mortality observed

Mammal oral dose No mortality observed 1 in 2.9E+05 

(1 in 44 to 1 in 8.86E+18)

Not calculated; no 

mortality observed

Freshwater Fish 

Mortality 

Default Slope = 4.5 

(2 – 9)

1 in 4.18E+08 

(1 in 216 to 1 in 

1.75E+31)

1 in 2.4E+10 

(1 in 515 to 1 in 

1.50E+38)1

Freshwater invertebrates 

Immobilization 

Default Slope = 4.5 

(2 – 9) 

1 in 3.34E+40 

(1 in 6.32E+14 to 1 in 

9.03E+78)

1 in 3.29E+33 

(1 in 2.97E+7 to 1 in 

8.14E+129)2

1

 Acute RQ for fish = 0.03. 

2

 Acute RQ for invertebrates = 0.002.

As shown in Table 5.2, the probability for acute direct effects (i.e., mortality) to individual listed 

fish (based on the most sensitive species, common carp) and the highest derived RQ value is 1 in 

2.4X1010. This reflects an average slope of 4.5. If the true dose response curve were steeper, the 
-Page 73 of 115- 

chance of an individual increases (e.g. slope of 9, chance is 1 in 515). The chance of an 

individual effect for aquatic invertebrates, based on the most sensitive species, Eastern oyster, is 

1 in 3.29X1033. 

 5.2.2. Listed Species Occurrence Associated with Penflufen Use 

The goal of the co-location analysis is determine whether sites of pesticide use are 

geographically associated with known locations of listed species [following the convention of the 

Services, the word ‘species’ in this assessment may apply to a ‘species’, ‘subspecies’, or an 

Evolutionary Significant Unit (ESU)]. At the screening level, this analysis is accomplished 

using the LOCATES database (version 2.10.3). The database uses location information for listed 

species at the county level and compares it to agricultural census data (from 2002) for crop 

production at the same county level of resolution. The product is a listing of Federally-listed 

species that are located in counties known to produce the crops upon which the pesticide will be 

used. A list of potentially directly affected species associated with the proposed new uses of 

penflufen is provided in Appendix F. Species potentially indirectly affected include all listed 

species. 

This preliminary analysis indicates that there is a potential for penflufen use to overlap with 

listed species and that a more refined assessment is warranted. The more refined assessment 

should involve clear delineation of the action area associated with proposed uses of penflufen 

and the best available information on the temporal and spatial co-location of listed species with 

respect to the action area. This analysis has not been conducted for this assessment. 
-Page 74 of 115- 

6. References 

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and Unsaturated Soil Zones: Users Manual for Release 3.12.2. National Exposure 

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issued May 5, 2006. 

48023547 Koehn, D. [Phenyl-UL-13C6/

14C] and [pyrazole-3-14C]BYF 14182: Hydrolytic degradation. 

Unpublished study performed and sponsored by Bayer CropScience AG, Monheim am Rhein, 

Germany, and submitted by Bayer CropScience LP, Research Triangle Park, North Carolina. 

Experiment initiated March 28, 2007, and terminated April 4, 2007. Final report issued July 18, 2008. 

48023548 Menke, U. 2009. [Phenyl-UL-13C6/

14C]BYF 14182 and [pyrazole-3-14C]BYF 14182: 

Phototransformation in aqueous buffer. Unpublished study performed and sponsored by Bayer 

CropScience AG, Monheim am Rhein, Germany, and submitted by Bayer CropScience LP, Research 

Triangle Park, North Carolina. Experiment initiated June 26, 2007, and terminated August 9, 2007. 

Final report issued August 27, 2009. 

48023549 Menke, U. 2009. [Phenyl-UL-13C6/

14C] and [pyrazole-3-14C]BYF 14182: Photolysis in natural water. 

Unpublished study performed and sponsored by Bayer CropScience AG, Monheim am Rhein, 

Germany, and submitted by Bayer CropScience LP, Research Triangle Park, North Carolina. 
-Page 76 of 115- 

Experiment initiated July 25, 2007 and terminated November 28, 2007. Final report issued August 31, 

2009. 

48023550 Heinemann, O. 2009. BYF14182: Determination of the quantum yield and assessment of the 

environmental half-life of the direct photo-degradation in water. Unpublished study performed and 

sponsored by Bayer CropScience AG, Monheim am Rhein, Germany, and submitted by Bayer 

CropScience LP, Research Triangle Park, North Carolina. Experiment initiated May 5, 2009 and 

terminated June 4, 2009. Final report issued June 30, 2009. 

48023552 Sneikus, J. [Phenyl-UL-14C]BYF14182: Aerobic soil metabolism/degradation and time-dependent 

sorption in four soils. Unpublished study performed and sponsored by Bayer CropScience AG, 

Monheim, Germany, and submitted by Bayer CropScience LP, Research Triangle Park, North 

Carolina. Experiment initiated September 26, 2005, and terminated March 21, 2006. Final report 

issued March 22, 2007. 

48023553 Mislankar, S.G. and K.A. Dallstream. 2009. [Phenyl-UL-14C] and [pyrazole-3-14C] BYF 14182: 

aerobic soil metabolism in two US soils. Unpublished study performed by Bayer CropScience AG, 

Monheim, Germany; AGVISE Laboratories, Northwood, North Dakota, Bayer CropScience, Stilwell, 

Kansas and sponsored and submitted by Bayer CropScience, Research Triangle Park, North Carolina. 

Experiment started February 20, 2007, and completed March 12, 2008. Final report issued September 

15, 2009. 

48023554 Stupp, H-P. and M. Telscher. [Pyrazole-3-14C]BCS-AF73126 (BYF 14182-pyrazolyl-AAP): 

degradation and time-dependent sorption in soils. Unpublished study performed and sponsored by 

Bayer CropScience AG, Monheim, Germany; and submitted by Bayer CropScience, Research Triangle 

Park, North Carolina. Study Completion Date July 31, 2009. 

48023555 Sneikus, J. 2009. [Pyrazole-3-14C] and [phenyl-UL-14C]BYF14182: anaerobic soil metabolism. 

Unpublished study performed and sponsored by Bayer CropScience AG, Monheim, Germany; and 

submitted by Bayer CropScience, Research Triangle Park, North Carolina. Study Completion Date 

May 30, 2008. 

48023556 Sneikus, J. [Pyrazole-3-14C]& [phenyl-UL-14C]BYF14182: Aerobic aquatic degradation. Unpublished 

study performed and sponsored by Bayer CropScience AG, Monheim, Germany; and submitted by 

Bayer CropScience, Research Triangle Park, North Carolina. Study Initiation Date March 30, 2007. 

Study Completion Date August 5, 2008. 

48023557 Meyer, B.N. 2008. [Phenyl-UL-14C] and [pyrazole-3-14C]BYF 14182: anaerobic aquatic metabolism. 

Unpublished study performed by Bayer CropScience, Stilwell, Kansas; and sponsored and submitted 

by Bayer CropScience, Research Triangle Park, North Carolina. Experiment started June 28, 2007, and 

completed January 25, 2008. Final report issued December 15, 2008. 

48023558 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in a California Soil, 2007. Unpublished 

study performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, ND; and 

California Agricultural Research, Inc., Kerman, CA; sponsored and submitted by Bayer CropScience, 

Research Triangle Park, NC. Mar. 10, 2010. 

48023559 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in Georgia Soil, 2007. Unpublished study 

performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, ND; and 

Southeast Ag Research, Inc., Chula, GA; sponsored and submitted by Bayer CropScience, Research 

Triangle Park, NC. Mar. 10, 2010. 

48023560 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in Idaho Soil, 2007. Unpublished study 

performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, ND; and Miller 

Research, Inc., Rupert, ID; sponsored and submitted by Bayer CropScience, Research Triangle Park, 

NC. Mar. 10, 2010. 

48023561 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in Ontario, Canada Soil, 2007. 

Unpublished study performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, 

ND; and Bayer CropScience, Rockwood, Ontario, Canada; sponsored and submitted by Bayer 

CropScience, Research Triangle Park, NC. Mar. 10, 2010. 

48023562 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in Saskatchewan, Canada Soil, 2007. 

Unpublished study performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, 

ND; and Bayer CropScience, Regina, Saskatchewan, Canada; sponsored and submitted by Bayer 

CropScience, Research Triangle Park, NC. Mar. 10, 2010. 

48023563 Lenz, M. 2010. Terrestrial Field Dissipation of BYF 14182 in Prince Edward Island, Canada Soil, 
-Page 77 of 115- 

2007. Unpublished study performed by Bayer CropScience, Stilwell, KS; AGVISE Laboratories, 

Northwood, ND; and Atlantic Agritech, Hunter River, Prince Edward Island, Canada; sponsored and 

submitted by Bayer CropScience, Research Triangle Park, NC. Mar. 10, 2010. 

48023564 Telscher, M. 2009. Determination of the Residues of BYF 14182 in/on Soil after Spraying of BYF 

14182 SC 100 (100 SC) in the Field in Northern France, United Kingdom, Sweden, Germany, Italy, 

and Spain. Report No. RA-2147/06; Document No. M-350568-01-2. Unpublished study performed by 

Bayer CropScience AG, Monheim, Germany; sponsored and submitted by Bayer CropScience AG, 

Monheim am Rhein, Germany. July 1, 2009. 

48023565 Lenz, M. 2010. Aquatic Dissipation of BYF 14182 FS 240 in a Cropped Arkansas Rice Field, 2008. 

Report No. RAELP039; Document No. M-365281-01-1. Unpublished study performed by Bayer 

CropScience, Stilwell, KS; AGVISE Laboratories, Northwood, ND; Mid-South Ag Research, Inc., 

Proctor, AR and Bayer Crop Science, Research Triangle Park, NC; sponsored and submitted by Bayer 

CropScience, Research Triangle Park, NC. Final report issued Mar. 15, 2010. 

48023719 Freitag, T. and M. Hoffmann. 2009. Determination of the storage stability of BYF14182 and its 

metabolites BYF14182-3-hydroxybutyl (BCS-AA10006) and BYF14182-pyrazolyl-AAP (AE 

2300037) in soil - Results for an interval of 0 to 12 and 24 months. Unpublished study performed and 

sponsored by Bayer CropScience AG, Monheim am Rhein, Germany and submitted by Bayer 

CropScience LP, USA. Experiment initiated September 21, 2007, and terminated October 22, 2009. 

Final report issued October 30, 2009. 

48023722 Wade, J.M. 2010. Storage Stability of BYF 14182 and its metabolites BYF 14182-3- hydroxy-butyl 

and BYF 14182-pyrazolyl-AAP in Raw Surface Water During Frozen Storage, USA, 2009. 

Unpublished study performed by Bayer CropScience, Stilwell, Kansas and sponsored by Bayer 

CropScience, Research Triangle Park, North Carolina. Experiment initiated June 4, 2009, termination 

date not reported. Final report issued March 8, 2010. 

48652501 Woodard, D. 2011. [Pyrazole-3-14C]BYF 14182: Determination of Bound Residue Formation in 

Sterile Aerobic Soil and Aerobic Aquatic Water/Sediment Test Systems. Unpublished study performed 

by Bayer CropScience, Stilwell, Kansas. Study completed on Nov. 8, 2011. 

6.2. Submitted Ecotoxicity Studies 

Guideline: 850.1010 Aquatic invertebrate acute toxicity, test, freshwater daphnids 

------------------------------------------------------------------------------------- 

MRID: 48023574 

Roberts, J.; Lam, C. (2008) Acute Toxicity of BYF 14182 Technical to Daphnia magna Under Static 

Conditions. Project Number: M/296362/01/1, EBELP005, M/296362/01/1/OCR. Unpublished study 

prepared by Bayer CropScience. 43 p. 

MRID: 48023575 

Banman, C.; Hoffmann, J.; Lam, C. (2009) Acute Toxicity of BYF 14182-3-Hydroxy-Butyl to Daphnia 

magna Under Static Conditions. Project Number: M/346259/01/1, EBELP027, M/346259/01/1/OCR. 

Unpublished study prepared by Bayer CropScience. 41 p. 

MRID: 48023576 

Bruns, E. (2009) Acute Toxicity of BYF14182-Pyrazolyl-AAP (Tech.) to the Waterflea Daphnia magna 

in a Static Laboratory Test System. Project Number: M/357192/01/2, EBELP102, E/320/3613/8. 

Unpublished study prepared by Bayer CropScience. 43 p. 

MRID: 48023577 

Banman, C.; Daly, R.; Lam, C. (2009) Acute Toxicity of BYF 14182 Technical to Crayfish Under Static 

Conditions. Project Number: M/350813/01/1, EBELP047, M/350813/01/1/OCR. Unpublished study 

prepared by Bayer CropScience. 44 p. 
-Page 78 of 115- 

MRID: 48024003 

Bruns, E. (2009) Acute Toxicity of BYF 14182 FS 240 G to the Waterflea Daphnia magna in a Static 

Laboratory Test System. Project Number: M/345436/01/2/OCR, EBELP079, M/345436/01/2. 

Unpublished study prepared by Bayer CropScience. 49 p. 

Guideline: 850.1025 Oyster acute toxicity test (shell deposition) 

------------------------------------------------------------------------------------- 

MRID: 48023578 

Gallagher, S.; Kendall, T.; Krueger, H. (2009) BYF 14182: A 96-Hour Shell Deposition Test with the 

Eastern Oyster (Crassostrea virginica). Project Number: M/343505/01/1, EBELP014, 

M/343505/01/1/OCR. Unpublished study prepared by Wildlife International, Ltd. 63 p. 

Guideline: 850.1035 Mysid acute toxicity test 

------------------------------------------------------------------------------------- 

MRID: 48023579 

Gallagher, S.; Kendall, T.; Krueger, H. (2008) BYF 14182: A 96-Hour Static Acute Toxicity Test with 

the Saltwater Mysid (Americamysis bahia): Amendment. Project Number: M/303018/01/1, EBELP012, 

149A/233. Unpublished study prepared by Wildlife International, Ltd. 62 p. 

Guideline: 850.1075 Fish acute toxicity test, freshwater and marine 

------------------------------------------------------------------------------------- 

MRID: 48023580 

Banman, C.; Hoffmann, J.; Lam, C. (2009) Acute Toxicity of BYF 14182 Technical to the Rainbow 

Trout (Oncorhynchus mykiss) Under StaticConditions. Project Number: M/343491/01/1, EBELP002, 

M/343491/01/1/OCR. Unpublished study prepared by Bayer CropScience. 46 p. 

MRID: 48023581 

Banman, C.; Hoffmann, J.; Lam, C. (2009) Acute Toxicity of BYF 14182 Technical to Bluegill (Lepomis 

macrochirus) Under Static Conditions. Project Number: M/343846/01/1, EBELP037, 

M/343846/01/1/OCR. Unpublished study prepared by Bayer CropScience. 46 p. 

MRID: 48023582 

Matlock, D.; Hoffmann, J.; Lam, C. (2009) Acute Toxicity of BYF 14182 Technical to the Fathead 

Minnow (Pimephales promelas) Under Static Conditions. Project Number: M/346776/01/1, EBELP026, 

M/346776/01/1/OCR. Unpublished study prepared by Bayer CropScience. 49 p. 

MRID: 48023583 

Ruhland, M. (2009) Acute Toxicity of BYF 14182 (Tech.) to Fish (Cyprinus carpio) Under Static 

Conditions. Project Number: M/344774/01/2, EBELP077, E/280/35559/2. Unpublished study prepared 

by Bayer CropScience. 51 p. 

MRID: 48023584 

Bruns, E. (2009) Acute Toxicity of Penflufen-3-Hydroxy-Butyl to Fish (Cyprinus carpio) Under Static 

Conditions - Limit Test. Project Number: M/357272/01/2, EBELP039, E/280/3739/2. Unpublished 

study prepared by Bayer CropScience. 49 p. 

MRID: 48023585 

Bruns, E. (2009) Acute Toxicity of Penflufen-Pyrazolyl-AAP to Fish (Cyprinus carpio) Under Static 

Conditions - Limit Test. Project Number: M/357274/01/2, EBELP103, E/280/3719/0. Unpublished 

study prepared by Bayer CropScience. 49 p. 
-Page 79 of 115- 

MRID: 48023586 

Banman, C.; Hoffmann, J.; Lam, C. (2009) Acute Toxicity of BYF 14182 Technical to the Sheepshead 

Minnow (Cyprinodon variegatus) Under Static Conditions. Project Number: M/343499/01/1, EBELP003, 

M/343499/01/1/OCR. Unpublished study prepared by Bayer CropScience. 47 p. 

MRID: 48024004 

Bruns, E. (2009) Acute Toxicity of BYF 14182 FS 240 G to Fish (Cyprinus carpio) Under Static 

Conditions. Project Number: M/345941/01/2/OCR, 

EBELP078, M/345941/01/2. Unpublished study prepared by Bayer CropScience. 55 p. 

Guideline: 850.1300 Daphnid chronic toxicity test 

------------------------------------------------------------------------------------- 

MRID: 48023587 

Banman, C.; Lam, C. (2009) Chronic Toxicity of BYF 14182 Technical to the Daphnia magna Under 

Static Renewal Conditions: Amended Report. Project Number: M/328667/02/1, EBELP006/1, 

M/328667/02/1/OCR. Unpublished study prepared by Bayer CropScience. 75 p. 

Guideline: 850.1400 Fish early-life stage toxicity test 

------------------------------------------------------------------------------------- 

MRID: 48023588 

Matlock, D.; Lam, C. (2009) Early Life Stage Toxicity of BYF 14182 Technical to the Fathead Minnow 

(Pimephales promelas) Under Flow-Through Conditions. Project Number: M/329464/01/1, EBELP004, 

M/329464/01/1/OCR. Unpublished study prepared by Bayer CropScience. 96 p. 

Guideline: 850.1730 Fish BCF 

------------------------------------------------------------------------------------- 

MRID: 48023589 

Justus, K. (2009) [Phenyl-UL-(Carbon 13)/(Carbon 14)]BYF 14182: Bioconcentration and 

Biotransformation in Fish (Lepomis macrochirus). Project Number: M/356580/01/2, MEF/09/100, 

M2881755/6. Unpublished study prepared by Bayer CropScience AG. 173 p. 

Guideline: 850.2100 Avian acute oral toxicity test 

------------------------------------------------------------------------------------- 

MRID: 48023591 

Stoughton, T.; Christ, M. (2009) Toxicity of BYF 14182 Technical During an Acute Oral LD50 with the 

Northern Bobwhite Quail (Colinus virginianus). Project Number: M/357031/01/1, EBELP015, 

M/357031/01/1/OCR. Unpublished study prepared by Bayer CropScience. 33 p. 

MRID: 48023592 

Fredricks, T.; Stoughton, T.; Christ, M. (2010) Toxicity of BYF 14182 Technical During an Acute Oral 

LD50 with the Canary (Serinus canaria): Amended Report. Project Number: M/361570/02/1, 

EBELL004/1, M/361570/02/1/OCR. Unpublished study prepared by Bayer CropScience. 86 p. 

MRID: 48024005 

Barfknecht, R. (2009) Acute Oral Toxicity for BYF 14182 FS 240 G with Northern Bobwhite Quail 

(Colinus virginianus). Project Number: M/348863/01/2/OCR, BAR/LD/100, M/348863/01/2. 

Unpublished study prepared by Bayer CropScience. 31 p. 

Guideline: 850.2200 Avian dietary toxicity test 
-Page 80 of 115- 

------------------------------------------------------------------------------------- 

MRID: 48023593 

Stoughton, T.; Christ, M.; Lam, C. (2009) Toxicity of BYF 14182 Technical During an Acute Dietary 

LC50 with the Northern Bobwhite Quail (Colinus virginianus). Project Number: M/358055/01/1, 

EBELP017, M/358055/01/1/OCR. Unpublished study prepared by Bayer CropScience. 44 p. 

MRID: 48023594 

Stoughton, T.; Lam, C. (2009) Toxicity of BYF 14182 Technical During an Acute Dietary LC50 with the 

Mallard Duck (Anas platyrhynchos). Project Number: M/348230/01/1, EBELP018, 

M/348230/01/1/OCR. Unpublished study prepared by Bayer CropScience. 46 p. 

Guideline: 850.2300 Avian reproduction test 

------------------------------------------------------------------------------------- 

MRID: 48023595 

Stoughton, T.; Christ, M.; Lam, C. (2009) Toxicity of BYF 14182 Technical on Reproduction to the 

Northern Bobwhite Quail (Colinus virginianus). Project Number: M/358260/01/1, EBELP019, 

M/358250/01/1/OCR. Unpublished study prepared by Bayer CropScience. 79 p. 

MRID: 48023596 

Christ, M.; Lam, C. (2009) Toxicity of BYF 14182 Technical on Reproduction to the Mallard Duck 

(Anas platyrhynchos). Project Number: M/358529/01/1, EBELP020, M/358529/01/1/OCR. Unpublished 

study prepared by Bayer CropScience. 74 p. 

Guideline: 850.3020 Honey bee acute contact toxicity 

------------------------------------------------------------------------------------- 

MRID: 48023597 

Schmitzer, S. (2007) Effects of BYF 14182 (Acute Contact and Oral) on Honey Bees (Apis mellifera L.) 

in the Laboratory: Final Report. Project Number: M/292797/01/2, 36581035, M/292797/01/2/OCR. 

Unpublished study prepared by Institut fuer Biologische Analytik und Consulting IBACON. 32 p. 

MRID: 48024006 

Schmitzer, S.; Sekine, T. (2009) Effects of BYF 14182 FS 240 G (Acute Contact and Oral) on Honey 

Bees (Apis mellifera L.) in the Laboratory: Final Report. Project Number: M/350450/01/2/OCR, 

48191035, M/350450/01/2. Unpublished study prepared by Institut fuer Biologische Analytik und 

Consulting IBACON. 32 p. 

Guideline: 850.4100 Terrestrial plant toxicity, Tier 1 (seeding emergence) 

------------------------------------------------------------------------------------- 

MRID: 48023598 

Gosch, H. (2009) BYF 14182 FS 240 g/L: Effects on Eleven Species of Non-Target Terrestrial Plants: 

Seedling Emergence and Growth Test (Tier 1). Project Number: SE08/005/TIER/1, EBELP045, 

M/353590/01/2/OCR. Unpublished study prepared by Bayer CropScience AG. 61 p. 

MRID: 48023599 

Gosch, H. (2009) Non-Target Terrestrial Plants: An Evaluation of the Effect of BYF 14182 FS 50 g/L in 

the Seedling Emergence and Growth Test. Project Number: SE09/013/TIER/1, EBGLP152, 

M/348694/01/2/OCR. Unpublished study prepared by Bayer CropScience AG. 23 p. 

Guideline: 850.4150 Terrestrial plant toxicity, Tier 1 (vegetative vigor) 
-Page 81 of 115- 

------------------------------------------------------------------------------------- 

MRID: 48023601 

Gosch, H. (2009) BYF 14182 FS 240 g/L: Effects on Eleven Species of Non-Target Terrestrial Plants: 

Vegetative Vigour Test (Tier 1). Project Number: M/353600/01/2/OCR, VV08/006/TIER/1, EBELP046. 

Unpublished study prepared by Bayer CropScience AG. 57 p. 

MRID: 48023602 

Gosch, H. (2009) Non-Target Terrestrial Plants: An Evaluation of the Effects of BYF 14182 FS 50 g/L in 

the Vegetative Vigour Test. Project Number: M/348690/01/2/OCR, VV09/014/TIER/1, EBELP151. 

Unpublished study prepared by Bayer CropScience AG. 23 p. 

Guideline: 850.4400 Aquatic plant toxicity test using Lemna spp. Tiers I and II 

------------------------------------------------------------------------------------- 

MRID: 48023603 

Banman, C.; Hoffmann, J.; Lam, C. (2009) Toxicity of BYF 14182 Technical to Duckweed (Lemna gibba 

G3) Under Static-Renewal Conditions. Project Number: M/343501/01/1/OCR, EBELP038/OCR, 

M/343501/01/1. Unpublished study prepared by Bayer CropScience. 51 p. 

Guideline: 850.5400 Algal toxicity, Tiers 1 and II 

------------------------------------------------------------------------------------- 

MRID: 48024007 

Ruhland, M. (2009) Pseudokirchneriella Subcapitata Growth Inhibition Test with BYF 14182 FS 240 G. 

Project Number: M/333595/01/2/OCR, EBELP080, M/333595/01/2. Unpublished study prepared by 

Bayer CropScience. 65 p. 

Guideline: 870.1100 Acute oral toxicity 

------------------------------------------------------------------------------------- 

MRID: 48023749 

Schungel, M. (2007) BYF 14182: Acute Toxicity in the Rat after Oral Administration. Project Number: 

M/294194/01/2, AT04001, T/3077694. 

Unpublished study prepared by Bayer HealthCare AG. 28 p. 

MRID: 48024008 

Rupprecht, K. (2010) Bridging Rationale for Acute Toxicology of PEN 240FS. Project Number: 

M/365029/01/1/OCR, M/365029/01/1, G202164. Unpublished study prepared by Bayer CropScience LP. 

10 p. 

MRID: 48024102 

Gillissen, U. (2009) BYF 14182 FS 240 (Red): Acute Toxicity in the Rat after Oral Administration. 

Project Number: M/356564/01/2/OCR, AT05520, M/356564/01/2. Unpublished study prepared by Bayer 

Ag Inst. of Toxicology. 29 p. 

MRID: 48024202 

Gillissen, U. (2009) BYF 14182 + Clothianidin + Metalaxyl + Trifloxystrobin FS 10,7+290+7,15+7,15: 

Acute Toxicity in the Rat After Oral Administration. Project Number: M/356568/01/2, AT05522, 

M/356568/01/2/OCR. Unpublished study prepared by Bayer Schering Pharma AG. 31 p. 
-Page 82 of 115- 

MRID: 48024302 

Gillissen, U. (2009) BYF 14182 + Prothioconazole + Metalaxyl FS 38.4+76.8+61.4: Acute Toxicity in 

the Rat after Oral Administration. Project Number: M/356701/01/2/OCR, AT05537, M/356701/01/2. 

Unpublished study prepared by Bayer Ag Inst. of Toxicology. 29 p. 

MRID: 48024402 

Gillissen, U. (2010) BYF 14182 + Prothioconazole FS 100+18 g/L: Acute Toxicity in the Rat after Oral 

Administration. Project Number: M/362429/01/2/OCR, AT05723, M/362429/01/2. Unpublished study 

prepared by Bayer Ag Inst. of Toxicology. 29 p. 

MRID: 48024502 

Gillissen, U. (2009) BYF 14182 & Trifloxystrobin FS 154 + 154 (Blue): Acute Toxicity in the Rat after 

Oral Administration. Project Number: M/357051/01/2, AT05553, M/357051/01/2/OCR. Unpublished 

study prepared by Bayer HealthCare AG. 29 p. 

MRID: 48024602 

Gillissen, U. (2010) BYF 14182 + Clothianidin FS 66.5+207 g/L: Acute Toxicity in the Rat After Oral 

Administration. Project Number: M/362454/01/2, AT05725, M/362454/01/2/OCR. Unpublished study 

prepared by Bayer Schering Pharma AG. 29 p. 

Guideline: 870.3800 Reproduction and fertility effects 

------------------------------------------------------------------------------------- 

MRID: 48023812 

Milius, A. (2009) Technical Grade BYF 14182: A Two-Generation Reproductive Toxicity Study in the 

Wistar Rat: Final Report. Project Number:M/357261/01/1, 07/R72/MK, M/357261/01/1/OCR. 

Unpublished study prepared by Bayer CropScience and Xenometrics, LLC. 1693 p. 

MRID: 48248902 

Milius, A. (2009) Technical Grade BYF 14182: A Dose Range-Finding Reproductive Toxicity Study in 

the Wistar Rat: Final Report. Project Number: 07/P72/JW, M/357262/01/1. Unpublished study prepared 

by Bayer CropScience. 480 p. 

Guideline: 850.1735 Whole sediment: acute freshwater invertebrates 

------------------------------------------------------------------------------------- 

MRID: 48023590 

Banman, C.; Matlock, D.; Lam, C. (2009) Spiked Whole Sediment 10-Day Toxicity Test of BYF 14182 

Technical to Chironomus dilutus (Formerly Known as Chironomus tentans). Project Number: 

M/353945/01/1, EBELP011, M/353945/01/1/OCR. Unpublished study prepared by Bayer CropScience. 

71 p. 

Non-Guideline Study 

------------------------------------------------------------------------------------- 

MRID: 48023604 

Citation: Banman, C.; Hoffmann, J.; Lam, C. (2007) Toxicity of BYF 14182 Technical to the Green Alga 

Pseudokirchneriella subcapitata. Project Number: M/295850/01/1/OCR, EBELP007/OCR, 

M/295850/01/1. Unpublished study prepared by Bayer CropScience. 55 p. 

MRID: 48023605 
-Page 83 of 115- 

Citation: Banman, C.; Hoffmann, J.; Lam, C. (2009) Toxicity of BYF 14182-3-Hydroxy-Butyl to the 

Green Alga Pseudokirchneriella subcapitata. Project Number: M/347970/01/1/OCR, EBELP028/OCR, 

M/347970/01/1. Unpublished study prepared by Bayer CropScience. 53 p. 

MRID: 48023606 

Citation: Bruns, E. (2009) Pseudokirchneriella subcapitata Growth Inhibition Test with BYF 14182-

Pyrazolyl-AAP. Project Number: M/346267/02/2/OCR, EBELP101/OCR, E/323/3618/6. Unpublished 

study prepared by Bayer CropScience. 69 p. 

MRID: 48023607 

Citation: Waibel, J. (2008) BYF 14182 FS 240 G: Toxicity to the Parasitoid Wasp Aphidius rhopalosiphi 

(DeStephani-Perez) (Hymenoptera: Braconidae) in the Laboratory. Project Number: 

M/311401/01/2/OCR, CW08/040/OCR, EBELP068. Unpublished study prepared by Bayer CropScience 

AG. 30 p. 

MRID: 48023608 

Citation: Waibel, J. (2009) Toxicity to the Parasitoid Wasp Aphidius rhopalosiphi (DeStephani-Perez) 

(Hymenoptera: Braconidae) Using a Laboratory Test BYF 14182 FS 50 G. Project Number: 

M/346081/01/2/OCR, CW09/009/OCR, EBELP148. Unpublished study prepared by Bayer CropScience 

AG. 30 p. 

MRID: 48023609 

Citation: Waibel, J. (2008) BYF 14182 FS 240 G: Toxicity to the Predatory Mite Typhlodromus pyri 

Scheuten (Acari, Phytoseiidae) in the Laboratory. Project Number: M/311411/01/2/OCR, 

CW08/039/OCR, EBELP069. Unpublished study prepared by Bayer CropScience AG. 35 p. 

MRID: 48023610 

Citation: Waibel, J. (2010) BYF 14182 FS 50 G: Toxicity to the Predatory Mite Typhlodromus pyri 

Scheuten (Acari, Phytoseiidae) Using a Laboratory Test. Project Number: M/349193/01/2/OCR, 

CW09/008/OCR, EBELP147. Unpublished study prepared by Bayer CropScience AG. 35 p. 

MRID: 48023611 

Citation: Leicher, T. (2009) BYF 14182 (Tech.): Acute Toxicity to Earthworms (Eisenia fetida) Tested in 

Artificial Soil with 5 Percent Peat. Project Number: M/294423/01/2/OCR, LRT/RG/A/95/07/OCR, 

E/310/3378/5. Unpublished study prepared by Bayer CropScience. 24 p. 

MRID: 48023612 

Citation: Leicher, T. (2007) BYF 14812 FS 240: Effects on Survival, Growth and Reproduction on the 

Earthworm Eisenia fetida Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/295772/01/2/OCR, LRT/RG/R/40/07/OCR, E/312/3383/3. Unpublished study prepared by Bayer 

CropScience AG. 38 p. 

MRID: 48023613 

Citation: Leicher, T. (2008) BYF 14182-3-Hydroxy-Butyl: Effects on Survival, Growth and 

Reproduction on the Earthworm Eisenia fetida Tested in Artificial Soil with 5 Percent Peat. Project 

Number: M/304291/01/2/OCR, LRT/RG/R/48/08/OCR, E/312/3439/5. Unpublished study prepared by 

Bayer CropScience AG. 44 p. 

MRID: 48023614 

Citation: Friedrich, S. (2009) BYF 14182-Pyrazolyl-AAP: Sublethal Toxicity to the Earthworm Eisenia 
-Page 84 of 115- 

fetida in Artificial Soil with 5 Percent Peat: Final Report. Project Number: M/349225/01/2/OCR, 

09/10/48/033/S/OCR, EBELP100. Unpublished study prepared by Biochem Agrar, Labor fuer 

Biologische und Chemische. 32 p. 

MRID: 48023615 

Citation: Leicher, T. (2009) BYF 14182 FS 50 G: Effects on Survival, Growth and Reproduction on the 

Earthworm Eisenia fetida Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/354676/01/2/OCR, LRT/RG/R/58/09/OCR, EBELP073. Unpublished study prepared by Bayer 

CropScience AG. 46 p. 

MRID: 48023625 

Citation: Frommholz, U. (2007) BYF 14182 FS 240 G: Influence on the Reproduction of the Collembola 

Species Folsomia candida Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/291241/01/2/OCR, FRM/COLL/56/07/OCR, E/314/3318/3. Unpublished study prepared by Bayer 

CropScience AG. 26 p. 

MRID: 48023626 

Citation: Kratz, M. (2007) BYF 14182 FS 240: Influence on Mortality and Reproduction on the Soil Mite 

Species Hypoaspis aculeifer Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/294547/01/2/OCR, KRA/HR/5/07/OCR, E/428/3306/6. Unpublished study prepared by Bayer 

CropScience AG. 34 p. 

MRID: 48023627 

Citation: Frommholz, U. (2009) Metabolite BYF 14182-3-Hydroxy-Butyl: Influence on the 

Reproduction of the Collembola Species Folsomia candida Tested in Artificial Soil with 5 Percent Peat. 

Project Number: M/348154/01/2/OCR, FRM/COLL/72/09/OCR, E/314/3620/9. Unpublished study 

prepared by Bayer CropScience AG. 25 p. 

MRID: 48023628 

Citation: Kratz, M. (2009) BYF 14182-3-Hydroxy-Butyl: Influence on Mortality and Reproduction on 

the Soil Mite Species Hypoaspis aculeifer 

Tested in Artificial Soil with 5 Percent Peat. Project Number: M/329899/01/2/OCR, 

KRA/HR/14/09/OCR, E/428/3601/4. Unpublished study prepared by Bayer CropScience AG. 32 p. 

MRID: 48023629 

Citation: Frommholz, U. (2009) Metabolite BYF 14182-Pyrazolyl-AAP: Influence on the Reproduction 

of the Collembola Species Folsomia candida 

Tested in Artificial Soil with 5 Percent Peat. Project Number: M/348117/01/2/OCR, 

FRM/COLL/73/09/OCR, E/314/3621/0. Unpublished study prepared by Bayer CropScience AG. 25 p. 

MRID: 48023630 

Citation: Kratz, M. (2009) BYF 14182-Pyrazolyl-AAP: Influence on Mortality and Reproduction on the 

Soil Mite Species Hypoaspis aculeifer Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/329902/01/2/OCR, KRA/HR/13/09/OCR, E/428/3600/3. Unpublished study prepared by Bayer 

CropScience AG. 32 p. 

MRID: 48023631 

Citation: Frommholz, U. (2009) BYF 14182 FS 050 G: Influence on the Reproduction of the Collembola 
-Page 85 of 115- 

Species Folsomia candida Tested in Artificial Soil with 5 Percent Peat. Project Number: 

M/344200/01/2/OCR, FRM/COLL/70/09/OCR, E/314/3603/0. Unpublished study prepared by Bayer 

CropScience AG. 25 p. 

MRID: 48023632 

Citation: Kratz, M. (2009) BYF 14182 FS 050: Influence on Mortality and Reproduction on the Soil Mite 

Species Hypoaspis aculeifer Tested in Artificial Soil with 5 % Peat. Project Number: 

M/329498/01/2/OCR, KRA/HR/12/09/OCR, E/428/3598/9. Unpublished study prepared by Bayer 

CropScience AG. 32 p. 
Appendix A. Chemical Names, Structures, and Maximum Reported Amounts of Penflufen and Its Degrad

Table 1. Penflufen and Its Major Environmental Degradates. 

Code Name/ Synonym Chemical Name Chemical Structure Study Type M

%

PARENT

Penflufen BYF 14182 

IUPAC: (RS)-N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro1,3-dimethyl-1

H-pyrazole-4-

carboxamide CAS: 1H-Pyrazole-4-carboxamide, N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethylCAS-no: 494793-67-8 Formula: C18 H24 F N3 O 

MW: 317.41 g/mole 

N

N

H

N

O

F

3CH

3CH

3CH CH3

3CH

MAJOR (

>10%) TRANSFORMATION PRODUCTS 

M01BYF 14182-3-

hydroxy-butyl

Penflufen-3-

hydroxy-butyl 

Pen-3HB 

(RS)-5-fluoro-N-[2-(3-hydroxy-1,3-dimethylbutyl)phenyl]-1,3-dimethyl-1

H-pyrazole-4-

carboxamide Formula: C18 H24 F N3 O2

MW: 333.41 g/mol 

N

N

H

N

O

F

3CH

3CH

3CH CH3

3CH

OH

Aerobic 

soil 

MRID 48023552 

Silt loam Sandy loam Loam Laacherhof AIII a Loam 

MRID 48023553 

Silt loam (phenyl label) 

Silt loam (pyrazole label) Sandy loam (phenyl label) Sandy loam (pyrazole label) 

-Page 86 of 115- 
Code Name/ M

Synonym Chemical Name Chemical Structure Study Type 

%

Anaerobic soil 

MRID 48023555 

Water (phenyl label) 

Sediment (phenyl label) System (phenyl label) Water (pyrazole label) Sediment (pyrazole label) System (pyrazole label) 

Aerobic aquatic 

AnglerweiherMRID 48023556 

Water (phenyl label) 

Sediment (phenyl label) System (phenyl label) Water (pyrazole label) Sediment (pyrazole label) System (pyrazole label) 

Hoenniger Weiher MRID 48023556 

Water (phenyl label) 

Sediment (phenyl label) System (phenyl label) Water (pyrazole label) Sediment (pyrazole label) System (pyrazole label) 

Field studies 

Terrestrial MRID 48023558 0.

MRID 48023559 0.2 MRID 48023560 1.MRID 48023561 0MRID 48023562 0MRID 48023563 1.MRID 48023564 

France 5.

UK 5Sweden 3.Germany 9.Italy 3Spain 2

-Page 87 of 115- 
Code Name/ M

Synonym Chemical Name Chemical Structure Study Type 

%

Aquatic MRID 48023565 0

M02 BYF 14182-

pyrazolyl-AAP 

Penflufen-3-

pyrazolyl-AAP 

AAP 

N-(2-acetylphenyl)-5-fluoro-1,3-dimethyl-1H-pyrazole-4-

carboxamide Formula: C14 H14 F N3 O2

MW: 275.28 g/mol 

N N H

N

O

F O

3CH

3CH

3CH

Aerobic soil 

MRID 48023552 

MRID 48023553 

Silt loam (phenyl label) 

Silt loam (pyrazole label) Sandy loam (phenyl label) Sandy loam (pyrazole label) 

Field studies 

Terrestrial MRID 48023558 0.

MRID 48023559 0MRID 48023560 0.7 MRID 48023561 0MRID 48023562 0.MRID 48023563 MRID 48023564 

France 1.UK 1.Germany 1.Italy 1

M60 BYF 14182-fluoro acid 

5-fluoro-1,3-dimethyl-1H-pyrazole4-carboxylic acid

Formula: C6 H7 F N2 O2

MW: 158.13 g/mol 

OH N

N

O

F

3CH

3CH

Aqueous photolysis

pH 7 (phosphate buffer) 

pH 7.8 (river water; pyrazole label) 

-Page 88 of 115- 
-Page 89 of 115- 

Code Name/ Synonym Chemical Name Chemical Structure Study Type M

%

Carbon dioxide Carbon dioxide 

Formula: CO2

Aerobic soil MRID 

48023552 

Silt loam 

Sandy loam Loam Laacherhof AIIIa loam 

MRID 48023553 

Silt loam (phenyl label) 

Silt loam (pyrazole label)Sandy loam (phenyl label) Sandy loam (pyrazole label)

Anaerobic soil Phenyl label 1

Pyrazole label 0

Aerobic aquatic Anglerweiher Phenyl label 

Pyrazole label 

Hoenniger Weiher 

Phenyl label 

Pyrazole label 

Anaerobic aquatic Phenyl label 0

Pyrazole label 0

Aqueous photolysis pH 7 (phosphate buffer; 

phenyl label) 

pH 7 (phosphate buffer; pyrazole label) pH 7.8 (river water; phenyl label) pH 7.8 (river water; pyrazole label) 

0

The table includes only those degradates that were addressed in the studies. Degradates that appear in the registrant's structure file that were used as reference standarenvironmental fate studies are not included in the table. 

O C O

nd means “not detected.” 
-Page 90 of 115- 

Table 2. Minor Environmental Degradate of Penflufen (<10% of the Applied Radioactivity). 

Code Chemical name Chemical structure Study Type Maximum 

(day) 

M58 BYF 14182-

pyrazole-4-carboxamide 

5-fluoro-1,3-dimethyl-1H-pyrazole4-carboxamide Formula: C6 H8 F N3 O 

MW: 157.15 g/mol 

N

N

O

F

3CH

3CH

NH2

Aqueous photolysis pH 7 (phospAqueous photolysis 

pH 7.8 (river water; pyrazole label) 

6.8 (2.9

Table 3. Degradates of Penflufen Found in Plant Tissue During the Aquatic Field Dissipation Study. 

Code Name/ Synonym Chemical Name Chemical Structure Study Type M01 BYF 14182-3-hydroxybutyl 

(RS)-5-fluoro-N-[2-(3-hydroxy-1,3-dimethylbutyl)phenyl]-1,3-dimethyl-1H-pyrazole-4-carboxamide Formula: C18 H24 F N3 O2

MW: 333.41 g/mol 

N N H

N

O

F

3CH

3CH

3CH

3CH

CH3 OH

Aquatic field dissipation (rice plants) 

M64BYF 14182-bisdesmethyl-3-

carboxylic acid

5-fluoro-1H-pyrazole-3-carboxylic acid Formula: C4 H3 F N2 O2MW: 130.08 g/mol 

Aquatic field dissipation (rice plants) 

O 

OH

N

NH F

1 nd means “not detected.” 
Appendix B. Tier 2 Summary Catalog of Submitted Ecological Effects Studies for 

Penflufen. 

Table of ecotoxicological endpoints 

Birds 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182)

Bobwhite 

quail 

acute, oral LD50 [mg a.i./kg bw] >4000 Stoughton & Christ; 2009 

M-357031-01-1

KIIA 8.1.1/01 

Canary acute, oral LD50 [mg a.i./kg bw] >2000 Fredricks, et.al. 2010 

M-361570-01-2

KIIA 8.1.1/02 

Bobwhite 

quail 

5-day feeding LC50 [mg a.i./kg feed] >8944 

= LDD50 [mg a.i./kg bw/d] >1697 

Stoughton, Christ, &Lam; 

2009 

M-358055-01-1

KIIA 8.1.2/01 

Mallard duck 5-day feeding LC50 [mg a.i./kg feed] >9923 

= LDD50 [mg a.i./kg bw/d] >2208 

Stoughton & Lam, 2009 

M-348230-01-1

KIIA 8.1.3/01 

Bobwhite 

quail 

22-weeks feeding 

chronic, reproduction 

NOEC [mg a.i./kg feed] 946 

= NOEL [mg a.i./kg bw/d] 96 

Stoughton, Christ & Lam, 

2009 

M-358260-01-1

KIIA 8.1.4/01 

Mallard duck 21-weeks feeding 

chronic, reproduction 

NOEC [mg a.i./kg feed] <292 

= NOEL [mg a.i./kg bw/d] <27 

Christ & Lam; 2009 

M-358529-01-1

KIIA 8.1.4/02 

PEN 240FS (representative formulation) 

Bobwhite 

quail 

Acute, oral LD50 [mg a.i./kg bw] >456 Barfknecht, 2009 

Aquatic organisms: Fish 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182) 

Rainbow trout acute, 96h, 

static 

LC50 [mg a.i./L] 0.31

NOEC [mg a.i./L] 0.110 

(mean measured) 

Banman, Hoffmann, 

Lam, 2009 

M-343491-01-1

KIIA 8.2.1.1/01 

Bluegill sunfish acute, 96h, 

static 

LC50 [mg a.i./L] 0.45

NOEC [mg a.i./L] 0.285 

(mean measured) 

Banman, Hoffmann, 

Lam, 2009 

M-343846-01-1

KIIA 8.2.1.2/01 

Fathead minnow acute, 96h, 

static 

LC50 [mg a.i./L] 0.116 

NOEC [mg a.i./L] 0.055 

(mean measured) 

Matlock, Hoffmann, 

Lam, 2009 

M-346776-01-1

KIIA 8.2.1.2/02 

Carp 

(Cyprinus carpio) 

acute, 96h, 

static 

LC50 [mg a.i./L] 0.090

NOEC [mg a.i./L] 0.061 

(mean measured) 

Ruhland, 2009 

M-344774-01-2

KIIA 8.2.1.2/03 

-Page 91 of 115- 
Test species Test design Ecotoxicological endpoint Reference 

Sheepshead 

minnow 

(Cyprinodon 

variegatus) 

acute, 96 h, 

static 

LC50 [mg a.i./L] 1.15 Banman, Hoffmann, 

Lam, 2009 

M-343499-01-1

KIIA 8.11.1/01 

Fathead minnow 

(Pimephales 

promelas) 

chronic, 35d, 

flow-through (ELS) 

NOEC [mg a.i./L] 0.0234

(based on growth as length) 

Matlock & Lam, 2009

M-329464-01-1

KIIA 8.2.4/01 

Bluegill sunfish bioconcentration in 

fish 

BCF (whole fish wet weight) 100 Bruns & Justus, 2009

M-356580-01-2

KIIA 8.2.6.1/01 

BYF 14182-3-hydroxy-butyl (metabolite) 

Carp 

(Cyprinus carpio) 

acute, 96h, 

static 

LC50 [mg metabolite/L] >36.3 Bruns, 2009 

M-357272-01-2

KIIA 8.2.1.3/01 

BYF 14182-pyrazolyl-AAP (metabolite) 

Carp 

(Cyprinus carpio) 

acute, 96h, 

static 

LC50 [mg metabolite/L] >0.799 Bruns, 2009 

M-357274-01-2

KIIA 8.2.1.3/02 

PEN 240FS (representative formulation) 

Carp 

(Cyprinus carpio) 

acute, 96h, 

static 

LC50 [mg a.i./L] between 0.0620 and 

0.166 0.101

Bruns, 2009 

Aquatic organisms: Invertebrates 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182) 

Daphnia magna acute, 48h, 

static 

EC50 [mg a.i./L] >4.66

(mean measured) 

Roberts & Lam, 2008

M-296362-01-1

KIIA 8.3.1.1/01 

Chironomus 

dilutus 

acute, 10 d, 

spiked sediment 

NOEC 10 d survival 34.4

[mg a.s./kg sediment] 

NOEC growth 8.51

[mg a.i./kg sediment] 

NOEC 10 d survival overlying 0.16

water [mg a.i./L] 

NOEC growth pore water 0.78

[mg a.i./L] 

Banman, Matlock, 

Lam, 2009 

M-353945-01-1

KIIA 8.5.1/01 

Crayfish, 

(Procambarus 

clarkia) 

acute, 96 h, 

static 

EC50 [mg a.i./L] >4.5

(mean measured) 

Banman, Daly, Lam, 

2009 

M-350813-01-1

KIIA 8.3.1.3 /01 

Daphnia magna chronic, 21d, 

static-renewal 

NOEC [mg a.i./L] 1.53

(mean measured) 

Banman & Lam, 2009

M-328667-01-2

KIIA 8.3.2.1/01 

Oyster 

(Crassostrea 

virginica, marine 

species) 

acute, 96h 

flow-through 

EC50 [mg a.i./L] 1.3 Gallager et al, 2009 

M-343505-01-1

KIIA 8.11.1/02 

-Page 92 of 115- 
Test species Test design Ecotoxicological endpoint Reference 

Mysid shrimp 

(Americamysis 

bahia, marine 

species) 

acute, 96h 

flow-through 

LC50 [mg a.i./L] 2.5 Gallager et al, 2008 

M-303018-01-1

KIIA 8.11.1/03 

BYF 14182-3-hydroxy-butyl (metabolite) 

Daphnia magna acute, 48h, 

static 

EC50 [mg metabolite/L] >62.0

(mean measured) 

Banman, Hoffmann, 

Lam, 2009 

M-346259-01-1

KIIA 8.3.1.1/02 

BYF 14182-pyrazolyl-AAP (metabolite) 

Daphnia magna acute, 48h, 

static 

EC50 [mg metabolite/L] >3.12

(mean measured) 

Bruns, 2009 

M-357192-01-2

KIIA 8.3.1.1/03 

PEN 240FS (representative formulation) 

Daphnia magna acute, 48h, 

static 

EC50 [mg a.i./L] 4.928

(mean measured) 

Bruns, 2009 

Aquatic organisms: Algae and Plants 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182) 

Pseudokirchneriella 

subcapitata 

chronic, 96h, 

static 

96h-ErC50 [mg a.i./L] >5.1

96h-EbC50 [mg a.i./L] >5.1

96h-EC50 cell density[mg a.i./L] >5.1 

Banman, Hoffman, 

Lam, 2007 

M-295850-01-1

KIIA 8.4/01 

Lemna gibba chronic, 7d, 

static renewal 

7d-EC50 values [mg a.i./L] > 4.7 Banman, Hoffmann, 

Lam, 2009 

M-343501-01-1

KIIA 8.6/01 

BYF 14182-3-hydroxy-butyl (metabolite) 

Pseudokirchneriella 

subcapitata 

chronic, 72 h, 

static 

72h-ErC50 [mg/L] >71.9

72 h-EbC50 [mg/L] 66.5 

72h- EC50 cell density [mg/L] 60.8 

Banman, Hoffmann, 

Lam, 2009 

M-347970-01-2

KIIA 8.4/03 

BYF 14182-pyrazolyl-AAP (metabolite) 

Pseudokirchneriella 

subcapitata 

chronic, 72 h, 

static 

72h-ErC50 [μg/L] >1071.5 Bruns, 2009 

M-346267-02-2

KIIA 8.4/02 

PEN 240 FS (representative formulation) 

Pseudokirchneriella 

subcapitata 

chronic, 72 h, 

static 

72h-ErC50 [mg a.i./L] >24.8

72h- EC50 cell density [mg a.i./L] 7.5 

Ruhland, 2009 

Soil macro-organisms 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182) 

-Page 93 of 115- 
Test species Test design Ecotoxicological endpoint Reference 

Eisenia fetida acute, 14 days 

(5% peat in test soil) 

LC50 [mg a.i./kg d.wt.s.] >1000 Leicher, 2007 

M-294423-01-2

KIIA 8.9.1/01 

PEN 240FS (representative formulation) 

Eisenia fetida chronic, 28 d 

(5% peat in test soil) 

NOEC growth 180

[mg a.i./kg d.wt.s.] 

NOEC reproduction 57.8

[mg a.i./kg d.wt.s.] 

Leicher, 2007 

M-295772-01-2

KIIA 8.9.2/01 

Folsomia candida chronic, 28 d 

(5% peat in test soil) 

NOEC reproduction 231.1

[mg a.i../kg d.wt.s.] 

Frommholz, 2007 

M-291241-01-2

KIIA 8.16.1/01 

Hypoaspis 

aculeifer 

chronic, 14 d 

(5% peat in test soil) 

NOEC reproduction 2000

[mg a.i./kg d.wt.s.] 

Kratz, 2009 

M-294547-01-2

KIIA 8.16.1/02 

BYF 14182-3-hydroxy-butyl (metabolite) 

Eisenia fetida chronic, 28 d 

(5% peat in test soil) 

NOEC growth and reproduction 

[mg/kg d.wt.s.] 1000 

 

Leicher, 2008 

M-304291-01-2

KIIA 8.9.2/02 

Folsomia candida chronic, 28 d 

(5% peat in test soil) 

NOEC [mg/kg d.wt.s.] 1000 Frommholz, 2009 

M-348154-01-2

KIIA 8.16.1/03 

Hypoaspis 

aculeifer 

chronic, 14 d 

(5% peat in test soil) 

NOEC [mg/kg d.wt.s.] 1000 Kratz, 2009 

M-329899-01-2

KIIA 8.16.1/04 

BYF 14182 pyrazolyl-AAP (metabolite) 

Eisenia fetida chronic, 28 d 

(5% peat in test soil) 

NOEC growth [mg/kg d.wt.s.] 1000 

NOEC reproduction 500 

 [mg/kg d.wt.s.] 

Friedrich, 2009 

M-349225-01-2

KIIA 8.9.2/03 

Folsomia candida chronic, 28 d 

(5% peat in test soil) 

NOEC [mg/kg d.wt.s.] 1000 Frommholz, 2009 

M-348117-01-2

KIIA 8.16.1/05 

Hypoaspis 

aculeifer 

chronic, 14 d 

(5% peat in test soil) 

NOEC [mg/kg d.wt.s.] 1000 Kratz, 2009 

M-329902-01-2

KIIA 8.16.1/06 

Bees 

Test species Test design Ecotoxicological endpoint Reference 

Penflufen (BYF 14182) 

Apis mellifera acute, 48 h, oral 

acute, 48 h, contact 

LD50 [μg a.i./bee] >108.2

LD50 [μg a.i./bee] >100 

Schmitzer, 2007 

M-292797-01-2

KIIA 8.7.1/01 

PEN 240 FS (representative formulation) 

Apis mellifera acute, 48 h, oral 

acute, 48 h, contact 

LD50 [μg a.i./bee] >111.7

LD50 [μg a.i./bee] >100 

Schmitzer, 2009 

-Page 94 of 115- 
Non-target arthropods: Parasitoids + Predatory mites 

Test species Test design Ecotoxicological endpoint Reference 

PEN 240 FS (representative formulation) 

Aphidius 

rhopalosiphi, 

adults 

laboratory, glass plates LR50 [g a.i./ha] >250

effect on reproduction at 250 g a.i./ha:

 64% 

Waibel, 2008 

M-311401-01-2

KIIA 8.8.1.1/01 

Typhlodromus pyri laboratory, glass plates LR50 [g a.i./ha] >250

effect on reproduction at 250 g a.i./ha:

 37% 

Waibel, 2008 

M-311411-01-2

KIIA 8.8.1.2/01 

-Page 95 of 115- 
Appendix C. Catalogue of Submitted Environmental Fate Studies for Penflufen. 

 Submitted Environmental Fate Studies for Penflufen, their Review Classifications, and 

Classification Justifications. 

Guideline Study Title MRID Classification Comments

Are data 

adequate for 

Risk 

Assessment? 

Current Additional 

Data Need 

835.2120 Hydrolysis 48023547 Acceptable 

Study was conducted at 50oC. 

Penflufen was stable at pHs 4, 7, and 

9. 

Yes None 

835.2240 

Photodegradation 

in Water 48023548 Supplemental 

Study duration was not sufficient. A 

large amount of parent remained 

undegraded at the termination of the 

study. Half-lives are of uncertain 

value. 

Yes 

An acceptable aqueous 

photolysis study 

conducted for a 

sufficient duration is 

recommended to 

confirm the results 

reported from the 

reviewed studies. 

Photodegradation 

in River Water 48023549 Supplemental 

Study duration was not sufficient. A 

large amount of parent remained 

undegraded at the termination of the 

study. Half-lives are of uncertain 

value. 

Quantum Yield 

of Penflufen 48023550 Supplemental 

Dark controls were not used. 

Irradiation lamp was not compared to 

natural sunlight (mercury vapor lamp 

was used). 

835.2410 Photodegradation 

on Soil -- -- Study not required since this is a seed 

treatment. -- -- 

835.4100 Aerobic Soil 

Metabolism 

48023552 Supplemental 

German soils. Study duration was not 

sufficient to characterize the 

degradation of the parent and 

formation and decline of major 

degradates. Half-lives were 

extrapolated beyond the study 

duration and thus are of uncertain 

value. Comparison to intended use 

sites in the US was not provided. 

Yes 

An acceptable aerobic 

soil metabolism study 

conducted for a 

sufficient duration to 

characterize the decline 

of the parent and 

formation and decline 

of major degradates is 

recommended to 

reduce the uncertainty 

regarding the aerobic 

degradation of 

penflufen 

48023553 Supplemental 

US soils. Study duration was 

insufficient to completely 

characterize the degradation of the 

parent and formation and decline of 

major degradates. 

48023554 Supplemental 

Study was conducted using a 

penflufen-pyrazolyl-AAP as the 

starting material. Extraction methods 

were not exhaustive, multiple 

extraction methods should have been 

explored. Major degradates were not 

identified. Comparison to intended 

use sites in the US was not provided. 

-Page 96 of 115- 
Are data 

Guideline Study Title MRID Classification Comments adequate for Current Additional 

Risk Data Need 

Assessment? 

835.4200 Anaerobic Soil 

Metabolism 48023555 Acceptable 

A large amount of parent material 

remained undegraded at the study 

termination (70-74%). Half-lives are 

extrapolated beyond the duration of 

the study. An additional study 

conducted for a longer duration will 

not likely improve the results. 

German soils were used in the study 

and were not compared to intended 

use sites in the US. 

No None 

835.4300 Aerobic Aquatic 

Metabolism 48023556 Supplemental 

Unexplained variability in the 

reported data (uncharacterized 

decline of the parent and major 

degradates). Anglerweiher 

water:sand system should not be used 

for risk assessment. Hoenniger 

Weiher water :sandy loam system is 

acceptable for risk assessment. 

Yes 

An additional 

acceptable aerobic 

aquatic study that 

includes a different 

water: sediment system 

is recommended to 

address the potential 

variability that exists 

between multiple 

aquatic systems. 

835.4400 

Anaerobic 

Aquatic 

Metabolism 

48023557 Supplemental 

A large amount of parent material 

remained undegraded at the study 

termination (86-90%; 120 DAT). 

Penflufen was just beginning to 

dissipate from the sediment; a study 

conducted for a sufficient 

determination may determine 

whether penflufen was in fact 

dissipating from the sediment. Halflive are extrapolated and are of 

uncertain value. System was only 

moderately reducing. Only a single 

water:sediment system was studied. 

Yes 

Two water:sediment 

systems are 

recommended from 

studies conducted for a 

sufficient duration to 

reduce the uncertainty 

regarding the anaerobic 

degradation. However, 

it is unlikely that 

additional studies 

would produce 

significantly different 

results. 

835.1230 

Mobility - 

Adsorption / 

Desorption 

48023546 Supplemental 

Residues were not accounted for in 

the intercalated solution in the initial 

adsorption step and each desorption 

step. Registrant-calculated percent 

adsorption values could not be 

confirmed due to lack of raw data. 

None of the test soils had OM 

content <1%. Foreign soils were used 

for the study, comparison 

information to intended US use sites 

was not provided. Yes 

An acceptable 

adsorption/desorption 

study is recommended 

to address uncertainties 

identified in the study 

reviews. 

48023544 Supplemental 

Study was conducted using a major 

transformation product (penflufenhydroxy butyl). Registrant-calculated 

percent adsorption values could not 

be confirmed due to lack of raw data. 

None of the test soils had an OM 

content <1%. Foreign soils were used 

for the study, comparison 

information to intended US use sites 

was not provided. 

-Page 97 of 115- 
Are data 

Guideline Study Title MRID Classification Comments adequate for Current Additional 

Risk Data Need 

Assessment? 

48023545 Supplemental 

Study was conducted using a major 

transformation product (penflufenpyrazolyl-AAP). Registrantcalculated percent adsorption values 

could not be confirmed due to lack of 

raw data. None of the test soils had 

an OM content <1%. Foreign soils 

were used for the study, comparison 

information to intended US use sites 

was not provided. 

835.6100 Terrestrial Field 

Dissipation 

48023558 Unacceptable 

Reported dissipation half-lives are 

comparatively shorter than other field 

studies (orders of magnitude). 

Additional dissipation routes (e.g., 

runoff) were not measured, therefore 

there is some other dissipation route 

occurring that has not been accounted 

for. Exhaustive extraction methods 

were not investigated. Depth of 

sampling was insufficient. 

Yes 

An acceptable 

terrestrial field 

dissipation study that 

studies the proposed 

use patterns (seed 

treatment) is 

recommended to 

address the 

uncertainties identified 

in the study reviews. 

48023559 Supplemental 

Test application rate was conducted 

at an exaggerated rate (10x proposed 

maximum labeled rate). Exhaustive 

extraction methods were not 

investigated. Depth of sampling was 

insufficient. 

48023560 Supplemental 

Test application rate was conducted 

at an exaggerated rate (10x proposed 

maximum labeled rate). Exhaustive 

extraction methods were not 

investigated. Depth of sampling was 

insufficient. Reported LOQ did not 

compare to validated LOQ. 

48023561 Supplemental 

Test application rate was conducted 

at an exaggerated rate (10x proposed 

maximum labeled rate). Exhaustive 

extraction methods were not 

investigated. Reported LOQ did not 

compare to validated LOQ. 

48023562 Supplemental 

Test application rate was conducted 

at an exaggerated rate (10x proposed 

maximum labeled rate). Exhaustive 

extraction methods were not 

investigated. Reported LOQ did not 

compare to validated LOQ. 

48023563 Supplemental 

Test application rate was conducted 

at an exaggerated rate. Exhaustive 

extraction methods were not 

investigated. Reported LOQ did not 

compare to validated LOQ. 

-Page 98 of 115- 
Are data 

Guideline Study Title MRID Classification Comments adequate for Current Additional 

Risk Data Need 

Assessment? 

48023564 Supplemental 

Study was conducted in ecoregions 

dissimilar to the intended use sites in 

the US. Comparisons to intended use 

sites in the US were not provided. 

Application rates were not verified 

using data from the monitoring 

devices (e.g., filter paper). 

835.6200 Aquatic Field 

Dissipation 48023565 Supplemental 

Test application rate was conducted 

at an exaggerated rate. Exhaustive 

extraction methods were not 

investigated. Reported LOQ did not 

compare to validated LOQ. Study 

was conducted on rice. Plant samples 

were analyzed for parent and 

degradates. Hydroxy butyl and a 

carboxylic acid degradate were 

detected in plant samples at low 

levels. Storage stability was not 

demonstrated for the longest storage 

period (MRID 48023722) 

Yes 

Although not required 

for current action, 

future actions with 

aquatic uses would 

require a second study 

in an aquatic system. 

850.1730 Fish 

Accumulation 48023589 Acceptable 

Low BCFs indicate that penflufen 

will not bioconcentrate in aquatic 

food webs. Mean TRR values were 

used in the calculation of BCFs. EPA 

typically uses maximum TRR values 

from whole fish, edible, and viscera 

tissues when calculating BCFs, 

however mean TRR values do not 

change the conclusions that would be 

drawn by using maximum values. 

Yes None 

860.1380 

Storage stability 

in soil 

48023719 

48176601 Acceptable 

Initial study MRID 48176601was not 

conducted for sufficient duration. 

Together these two studies satisfy the 

guideline requirement. 

Yes 

None 

Storage Stability 48023722 Supplemental 

Study duration was insufficient. 

Stability was demonstrated through 

222 days, however it should have 

been conducted for at least as long as 

the longest storage period (362 days). 

An acceptable storage 

stability study in water 

conducted for a 

sufficient duration, 

using water from the 

aquatic field 

dissipation study. 

-Page 99 of 115- 
Appendix D. Product Chemistry and Environmental Fate Summary of Penflufen 

Product Chemistry of Penflufen 

Chemical Name: Penflufen (BYF 14182) 

IUPAC: N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethyl-1H-pyrazole-4-carboxamide 

CAS: 1H-Pyrazole-4-carboxamide, N-[2-(1,3-dimethylbutyl)phenyl]-5-fluoro-1,3-dimethylChemical Abstracts registry number: 494793-67-8 

Synonyms: BYF 14182, Penflufen 

Molecular Formula: C18 H24 F N3 O

Molecular Weight: 317.41 g/mol 

Chemical Structure: 

N N H

N

O

F

3CH

3CH

3CH CH3

3CH

Environmental Fate Summaries of Penflufen (BYF 14182)

Detailed information regarding the fate and transport of penflufen in the environment is provided 

in the study summaries below. Data evaluation records were completed in cooperation with 

Canada (PMRA) and Australia (APVMA) as part of the Global Joint Review framework. 

Hydrolysis - - EPA Guideline: 161-1 (835.2120) 

MRID: 48023547 

Penflufen was stable in sterile aqueous buffer solutions (pH 4, 7 and 9) that were incubated in the 

dark at 50°C for 7 days. 

-Page 100 of 115- 
Since penflufen was stable under the conditions of this study, the experiment was not repeated at 

a lower temperature or with a second position of radiolabel. Although USEPA and OECD 

guidelines require laboratory hydrolysis studies be conducted at environmentally relevant 

temperatures (20-25oC), there was little to no degradation via hydrolysis at 50oC, therefore an 

additional study at a lower temperature is not required at this time. 

Study Acceptability: This study is classified ACCEPTABLE. 

Photolysis in Water - - EPA Guideline: 161-2 (835.2240) 

MRID: 48023548

Penflufen is moderately degraded by photolytic processes at 25°C in aqueous buffer solution of 

pH 7, with a calculated combined label half-life of 17 days; corrected environmental half-life for 

Phoenix, Arizona and Athens, Greece of 83 and 131 days, respectively. No major transformation 

products are formed. Penflufen degrades to numerous very minor transformation products and 

CO2 (Figure 2, p. 66) 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023549 

In sterilized river water, penflufen is degraded by photolytic processes at 25°C, with a calculated 

half-life of 3.85 days; corrected environmental half-life in Tokyo, Japan is 36 days. The only 

major transformation product, BYF 14182-fluoro acid, is degraded to the only identified minor 

transformation product, BYF 14182-pyrazole-4-carboxamide. Numerous unidentified minor 

transformation products are formed. Formation of CO2 and organic volatiles is negligible.

USEPA Study Acceptability: This study is classified SUPPLEMENTAL.

Adsorption, Desorption and Mobility in Soil - - EPA Guideline: 163-1 (835.1230) 

MRID: 48023546 

Overall medium values of adsorption were determined for the active substance penflufen. Except 

for organic carbon content (a weak correlation), the coeffients for adsorption and desorption did 

not correlate with other physico-chemical properties of soil. 

Using the Standardized Soil Mobility Classification Guidance according to the Food and 

Agriculture Organization (FAO) of the United Nations adopted by USEPA and using reviewer 

calculated adsorption Koc values presented in Table 7 of this DER, penflufen is characterized as 

being moderately mobile in the test soils. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023544 BYF 14182-3-hydroxy-butyl 

-Page 101 of 115- 
Overall low values of adsorption were determined for metabolite BYF14182-3-hydroxy-butyl. 

Except for organic carbon, there was also no obvious dependence of Freundlich coefficients KF

for adsorption and desorption to correlate with other physico-chemical properties of soil. The 

same applies for a dependence of adsorption or desorption on pH of soil. The desorption 

constants KF(des) were higher by a factor of 1.3 compared to the respective adsorption constants, 

indicating some enhanced sorption of the compound once adsorbed to soil. 

Using the Standardized Soil Mobility Classification Guidance according to the Food and 

Agriculture Organization (FAO) of the United Nations adopted by USEPA and using reviewer 

calculated adsorption Koc values presented in Table 6 of this DER, BYF14182-3-hydroxy-butyl 

is characterized as being mobile in the test soils. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023545 BYF 14182-pyrazolyl-AAP 

Overall high values of adsorption were determined for metabolite BYF14182-pyrazolyl-AAP. 

Coefficients for adsorption did not correlate with other physico-chemical properties of soil. 

There was also no obvious dependence of adsorption or desorption on pH of soil. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

Aerobic Soil Metabolism EPA Guideline: 162-1 (835.4100) 

MRID: 48023552

Penflufen dissipated with reviewer-calculated half-lives of 118-239 days in the four German 

soils. The only major transformation product was BYF14182-3-hydroxy-butyl, with maximum 

concentrations of 7.2-15.2% of the applied at 120 days posttreatment (study termination). No 

minor transformation products were identified, and no distinct HPLC peaks totaled ≥2.1% of the 

applied. Unidentified [14C]compounds totaled up to 6.0% of the applied. All degradation 

products appeared to be transient with either further transformation to their metabolic 

downstream products or substantially integrated into the soil matrix as nonextractable residues. 

A transformation pathway was provided by the study author. Based on the study results, the 

route of aerobic degradation of penflufen in soil is characterized by the following major 

processes: 

• Hydroxylation at the alkyl side chain in the 3-position to form BYF14182-3-hydroxybutyl; 

• Formation of nonextractable (bound) residues; and 

• Mineralization (formation of CO2). 

This study is acceptable for delineating the route of transformation of penflufen; however, 

extrapolation past the study duration for calculating half-lives leads to uncertainty in those 

extrapolated values. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL

-Page 102 of 115- 
MRID: 48023553 

Penflufen dissipated with reviewer-calculated nonlinear half-lives of 249 days in the silt loam 

soil and 432 days in the sandy loam soil. BYF14182-3-hydroxy-butyl was a major 

transformation product in both soils, with maximum concentrations of 9.4-17.5% of the applied 

at 271-365 days posttreatment. BYF 14182-pyrazolyl-AAP was a major transformation product 

in the silt loam soil with maximum concentrations of 11.3-13.4% of the applied at 273-365 days 

posttreatment, and was a minor transformation product in the sandy loam soil with maximum 

concentrations of 1.9-2.2%. At 365 days posttreatment, nonextractable [14C]residues averaged 

17.6-25.8% of the applied and CO2 totaled 7.7-9.9%. 

Based on the study results, the route of aerobic degradation of penflufen in soil is characterized 

by the hydroxylation at the alkyl side chain in the 3-position to form BYF 14182-3-hydroxybutyl, which further oxidizes to BYF 14182-pyrazolyl-AAP (Figure 31, p. 82). Degradation 

results in formation of nonextractable residues and CO2. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL

MRID: 48023554 BYF 14182-pyrazolyl-AAP 

BYF 14182-pyrazolyl-AAP dissipated with reviewer-calculated half-lives of 115.5 in the silt 

loam soil, 256.7 days in the sandy loam soil, 231.0 days in the loam soil, and 128.4 days in the 

clay loam soil. No major or minor transformation products were identified. Unknown C was a 

major transformation product in the loam soil, reaching maximum concentrations of 7.3% of the 

applied in the silt loam soil, 5.2% in the sandy loam soil, 10.0% in the loam soil, and 6.1% in the 

clay loam soil (maximum averages 6.5%, 4.9%, 9.1%, and 5.6%, respectively) at 3-14 days 

posttreatment and decreasing to averages of 0.4-2.6% at 122 days. In all four soils, four 

unidentified components (A, B, D, and E) each averaged ≤5.9% of the applied throughout the 

experiment. At 122 days posttreatment, total extractable residues averaged 51.4-73.4% of the 

applied, nonextractable residues averaged 22.6-38.2%, and 14CO2 averaged 3.7-8.7%. Formation 

of other volatile radioactivity was insignificant for all soils at any sampling interval (≤0.1% AR). 

A transformation pathway was not provided by the study author. Based on the study results, BYF 

14182-pyrazolyl-AAP degrades to several unidentified and mostly minor compounds and CO2, 

and is bound to the soil. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

Anerobic Soil Metabolism EPA Guideline: 162-2 (835.4200) 

MRID: 48023555 

-Page 103 of 115- 
Penflufen degrades very slowly under the conditions of anaerobic soil degradation testing in the 

laboratory, with reviewer-calculated half-lives in the water-silt loam soil system of 866 days in 

the total system, 990 days in the soil, and 173 days in the water layer. Dissipation was by 

adsorption of residues to the soil. Volatilization is minimal. The only transformation product, 

BYF14182-3-hydroxy butyl, was present in equivalent concentrations prior to flooding and was 

stable post-flooding.

USEPA Study Acceptability: This study is classified ACCEPTABLE 

Aerobic Aquatic Metabolism EPA Guideline: 162-4 (835.4300) 

MRID: 48023556

Penflufen degraded slowly under the conditions of aerobic aquatic degradation testing in the 

laboratory, with reviewer-calculated single first-order half-lives of 267 and 301 days in the total 

system. Only one system (Hoenniger) should be used for risk assessment due to unexplained 

variability in the total recovery in the Anglerweiher system. One transformation product, 

BYF14182-3-hydroxy-butyl, was identified at maximum average concentrations of 12.1-12.8% 

of the applied in the Anglerweiher water:sand sediment total system and 1.7-2.1% in the 

Hoenniger Weiher water:sandy loam sediment system. Nonextractable [14C]residues averaged 

10.1-19.8% of the applied at 120 days posttreatment. Volatilization was minimal. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

Anerobic Aquatic Metabolism EPA Guideline: 162-3 (835.4400) 

MRID: 48023557 

Penflufen is stable in an anaerobic water-sediment system, with a non-transformed (SFO) halflife of greater than 6 years in the total system. Penflufen applied to the water surface dissipates 

with a nonlinear half-life of approximately 48 days, with elimination due to movement into the 

sediment. 

A transformation pathway was not proposed by the study author and could not be developed 

based on the study results. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL.

Terrestrial Field Dissipation EPA Guideline: 164-1 (835.6100) 

MRID: 48023558 

Penflufen (BYF 14182) dissipated with a reviewer-calculated dissipation time of 1.88 days 

(DFOP) and a DT90 of 138 days, with residues not detected above the LOQ below the 15-30 cm 

depth. The transformation products BYF 14182-3-hydroxy-butyl and BYF 14182-pyrazolylAAP were both detected in the top soil layer only, at levels below the LOQ. 

-Page 104 of 115- 
USEPA Study Acceptability: This study is classified UNACCEPTABLE. 

MRID: 48023559 

Penflufen (BYF 14182) dissipated with a reviewer-calculated DT50 of 11 days (DFOP), a DT90 

of 598 days (DFOP), with residues generally not detected above the LOQ below the 0-15 cm 

depth. Carryover of residues at 269 days posttreatment was ca. 20% of the zero-time recovery of 

BYF 14182 (detected as BYF 14182). The transformation products BYF 14182-3-hydroxy-butyl 

and BYF 14182-pyrazolyl-AAP were both detected in the top soil layer only, at levels below the 

LOQ. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL.

MRID: 48023560 

Penflufen (BYF 14182) dissipated with a reviewer-calculated dissipation half-life of 308 days 

(DFOP) for the total soil profile, DT 90 >2000 days. The DT90 was extrapolated beyond the 

study duration, however it illustrates the potential for penflufen to persist at low concentrations 

must longer than the estimated 1st half-life. Penflufen was detected above the LOQ to a 

maximum depth of 45-60 cm. Carryover of residues at 532 days posttreatment was ca. 29% of 

the target application rate (ca. 27% detected as BYF 14182) and 39.3% of the zero-time recovery 

of BYF 14182. The transformation products BYF 14182-3-hydroxy-butyl and BYF 14182-

pyrazolyl-AAP were both detected above the LOQ in the top soil layer only, at individual 

replicate maximum concentrations of 2.16 ppb (at 166 days) and 1.23 ppb (at 7 days), 

respectively (1.4% and 0.9% of the BYF 14182 target application rate, respectively). 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023561 

Penflufen (BYF 14182) dissipated with a reviewer-calculated DT50 of 14 days (IORE), DT90 of 

436 days, with residues not detected above the LOQ below the 0-15 cm depth. Carryover of 

residues at 168 days posttreatment was ca. 13% of the target application rate (ca. 10% detected 

as BYF 14182), and ca. 14% of the zero-time recovery of BYF 14182. The transformation 

products BYF 14182-3-hydroxy-butyl and BYF 14182-pyrazolyal-AAP were both detected in 

the top soil layer only, at levels below the LOQ. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023562 

Penflufen (BYF 14182) dissipated with a reviewer-calculated dissipation half-life of ca. 200 

days (DFOP), with residues not detected above the LOQ below the 0-15 cm depth. A DT90 was 

calculated at 1480 days indicating that although the compound dissipates with an initial half-life 

of 200 days, subsequent half-lives are much longer and penflufen may persist at low 

concentrations for a long time. Carryover of residues at 509 days posttreatment was 17.5% of the 

target application rate (15.0% detected as BYF 14182) and ca. 25% of the zero-time recovery of 

BYF 14182. The transformation products BYF 14182-3-hydroxy-butyl and BYF 14182-

pyrazolyl-AAP were both detected in the top soil layer only, at levels below the LOQ. 

-Page 105 of 115- 
US EPA Study Acceptability: This study is classified SUPPLEMENTAL. 

MRID: 48023563 

Penflufen (BYF 14182) dissipated with a reviewer-calculated half-life of ca. 15 days (DFOP), a 

DT90 of 1,270 days for the total soil profile, with residues not detected below the 15-30 cm 

depth (with one exception). This clearly shows that although the first half-life may be 

comparatively short to subsequent half-lives the compound will persist at low concentrations for 

a long time. Carryover of residues at 538 days posttreatment was ca. 18% of the target 

application rate (ca. 16% detected as BYF 14182), and 22.4% of the zero-time recovery of BYF 

14182. The transformation products BYF 14182-3-hydroxy-butyl and BYF 14182-pyrazolylAAP were both detected above the LOQ in the top soil layer only, at individual replicate 

maximum concentrations of 2.43 ppb (at 367 days) and 2.17 ppb (at 7 days), respectively (1.3% 

and 1.4% of the BYF 14182 target application rate, respectively). 

US EPA Study Acceptability: This study is classified SUPPLEMENTAL.

MRID: 48023564 

Penflufen (BYF 14182) dissipated with a reviewer-calculated SFO half-life of 100-193 days 

(non-transformed regression) from Northern Europe study sites (France, United Kingdom, 

Sweden, Germany) and 53-77 days (nonlinear regression) from Southern Europe study sites 

(Italy and Spain), based on residues in the 0-10 cm soil depth. Residues of BYF 14182 were 

generally not detected below the 20-30 cm depth. BYF 14182 declined to 12.9-17.1% of the 

target application rate at the end of the 719-749 day study period for the Northern Europe study 

sites, and to 3.06-5.41% of the target application rate at the end of the 720-735 day study period 

for the Southern Europe study sites. The transformation product BYF 14182-3-hydroxy-butyl 

was detected in the 0-10 cm depth at an individual replicate maximum concentration of 5.37-9.13 

ppb at the France, United Kingdom, and Germany study sites and below the LOQ at the Sweden, 

Italy, and Spain study sites and BYF 14182-pyrazolyl-AAP was not detected above the LOQ at 

any study site. 

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

Fish Accumulation EPA Guideline 165-4 (850.1730) 

MRID: 48023589

BYF 14182 accumulated in bluegill sunfish with a total residue bioconcentration factor of about 

100 to 103 X for whole fish (sum of radio labeled compounds, BYF 14182 parent, metabolites and 

mineralization products). After 14 days in uncontaminated water, 98% of the radioactivity was depurated 

from whole fish at both concentrations (nominal concentrations of 0.45 μg/L and 4.50 μg/L).

USEPA Study Acceptability: This study is classified Acceptable.

Storage Stability EPA Guideline (860.1380) 

-Page 106 of 115- 
MRID: 48023719 

Penflufen and BYF 14182-3-hydroxybutyl are stable when stored frozen at <-18 °C for 761 days. 

BYF 14182-pyrazolyl-AAP may be stable when stored frozen at <-18 °C for 844 days. 

USEPA Study Acceptability: This study is classified ACCEPTABLE.

MRID: 48023722 

Penflufen and its transformation products BYF 14182-3-hydroxy-butyl and BYF 14182-

pyrazolyl-AAP were stable in frozen water for a minimum of 222 days (p. 17).

USEPA Study Acceptability: This study is classified SUPPLEMENTAL. 

-Page 107 of 115- 
Appendix E. Aquatic Model Input/Output Data. 

Summary of Input/Output Files. 

File name Date Location/Simulation 

Input Files for PRZM/EXAMS

Potato.prz Sept. 6, 2011 Potato Use 

Beans.prz Sept. 6, 2011 Beans and Peas Use 

Crop Scenario Files for PRZM/EXAMS

IDNpotato_WirrgSTD.txt Dec. 20, 2004 Bingham, County, ID/Potato and tuberous corm 

MSsoybeanSTD.txt Aug. 9, 2001 Yazoo, County, MS/Beans and Peas 

Weather Data Files for PRZM/EXAMS

W12844.dvf July 3, 2002 West Palm Beach, Florida 

W03812.dvf July 3, 2002 Asheville, North Carolina 

Example Input/Output Data for Individual Simulations 

PRZM/EXAMS Example Input/Output File. 

stored as Pen_potato_unex.out 

Chemical: penflufen 

PRZM environment: IDNpotato_WirrigSTD.txt modified Tueday, 29 May 2007 at 13:55:22 

EXAMS environment: pond298.exv modified Tueday, 26 August 2008 at 06:14:08 

Metfile: w24156.dvf modified Tueday, 26 August 2008 at 06:15:52 

Water segment concentrations (ppb) 

Year Peak 96 hr 21 Day 60 Day 90 Day Yearly 

1961 0.1895 0.1873 0.1791 0.1717 0.1662 0.09502 

1962 0.1416 0.1415 0.141 0.1397 0.1387 0.1358 

1963 0.3339 0.3314 0.3256 0.3217 0.3161 0.2378 

1964 0.4667 0.4644 0.4555 0.4478 0.4462 0.3774 

1965 0.4213 0.4208 0.42 0.4158 0.4132 0.4059 

1966 0.4535 0.453 0.4516 0.447 0.4463 0.4212 

1967 0.6288 0.6262 0.6167 0.6094 0.6029 0.5243 

1968 0.6364 0.635 0.6312 0.6231 0.6176 0.5805 

1969 0.7028 0.7008 0.6951 0.6872 0.6788 0.6238 

1970 1.309 1.3 1.273 1.244 1.216 0.9492 

1971 1.081 1.081 1.08 1.078 1.076 1.045 

1972 1.008 1.008 1.007 1.006 1.004 0.9773 

1973 0.9816 0.9801 0.9762 0.9653 0.9568 0.9369 

1974 1.334 1.329 1.308 1.273 1.251 1.088 

1975 1.293 1.291 1.281 1.264 1.251 1.185 

1976 1.171 1.171 1.17 1.169 1.167 1.138 

1977 1.228 1.226 1.217 1.202 1.19 1.13 

1978 1.405 1.401 1.385 1.356 1.337 1.22 

1979 1.243 1.243 1.242 1.24 1.238 1.204 

1980 1.204 1.203 1.201 1.193 1.184 1.154 

1981 1.433 1.429 1.417 1.387 1.367 1.241 

1982 1.343 1.341 1.334 1.325 1.318 1.275 

1983 1.339 1.337 1.331 1.325 1.318 1.27 

1984 1.272 1.271 1.268 1.258 1.248 1.23 

-Page 108 of 115- 
1985 1.2 1.2 1.199 1.198 1.196 1.163 

1986 1.137 1.136 1.131 1.126 1.12 1.1 

1987 1.146 1.144 1.137 1.125 1.115 1.074 

1988 1.054 1.054 1.054 1.052 1.05 1.017 

1989 0.9775 0.9774 0.9768 0.9755 0.974 0.9485 

1990 1.012 1.01 1.003 0.988 0.9798 0.9349 

Sorted results 

Prob. Peak 96 hr 21 Day 60 Day 90 Day Yearly 

0.032258064516129 1.433 1.429 1.417 1.387 1.367 1.275 

0.0645161290322581 1.405 1.401 1.385 1.356 1.337 1.27 

0.0967741935483871 1.343 1.341 1.334 1.325 1.318 1.241 

0.129032258064516 1.339 1.337 1.331 1.325 1.318 1.23 

0.161290322580645 1.334 1.329 1.308 1.273 1.251 1.22 

0.193548387096774 1.309 1.3 1.281 1.264 1.251 1.204 

0.225806451612903 1.293 1.291 1.273 1.258 1.248 1.185 

0.258064516129032 1.272 1.271 1.268 1.244 1.238 1.163 

0.290322580645161 1.243 1.243 1.242 1.24 1.216 1.154 

0.32258064516129 1.228 1.226 1.217 1.202 1.196 1.138 

0.354838709677419 1.204 1.203 1.201 1.198 1.19 1.13 

0.387096774193548 1.2 1.2 1.199 1.193 1.184 1.1 

0.419354838709677 1.171 1.171 1.17 1.169 1.167 1.088 

0.451612903225806 1.146 1.144 1.137 1.126 1.12 1.074 

0.483870967741936 1.137 1.136 1.131 1.125 1.115 1.045 

0.516129032258065 1.081 1.081 1.08 1.078 1.076 1.017 

0.548387096774194 1.054 1.054 1.054 1.052 1.05 0.9773 

0.580645161290323 1.012 1.01 1.007 1.006 1.004 0.9492 

0.612903225806452 1.008 1.008 1.003 0.988 0.9798 0.9485 

0.645161290322581 0.9816 0.9801 0.9768 0.9755 0.974 0.9369 

0.67741935483871 0.9775 0.9774 0.9762 0.9653 0.9568 0.9349 

0.709677419354839 0.7028 0.7008 0.6951 0.6872 0.6788 0.6238 

0.741935483870968 0.6364 0.635 0.6312 0.6231 0.6176 0.5805 

0.774193548387097 0.6288 0.6262 0.6167 0.6094 0.6029 0.5243 

0.806451612903226 0.4667 0.4644 0.4555 0.4478 0.4463 0.4212 

0.838709677419355 0.4535 0.453 0.4516 0.447 0.4462 0.4059 

0.870967741935484 0.4213 0.4208 0.42 0.4158 0.4132 0.3774 

0.903225806451613 0.3339 0.3314 0.3256 0.3217 0.3161 0.2378 

0.935483870967742 0.1895 0.1873 0.1791 0.1717 0.1662 0.1358 

0.967741935483871 0.1416 0.1415 0.141 0.1397 0.1387 0.09502 

0.1 1.3426 1.3406 1.3337 1.325 1.318 1.2399 

 Average of yearly averages:

 0.889417333333334 

Inputs generated by pe5.pl - Novemeber 2006 

Data used for this run: 

Output File: Pen_potato_unex 

Metfile: w24156.dvf 

PRZM scenario: IDNpotato_WirrigSTD.txt 

EXAMS environment file: pond298.exv 

Chemical Name: penflufen 

Description Variable Name Value Units Comments 

Molecular weight mwt 317.41 g/mol 

Henry's Law Const. henry atm-m^3/mol 

Vapor Pressure vapr 9e-9 torr 

-Page 109 of 115- 
Solubility sol 10.9 mg/L 

Kd Kd mg/L 

Koc Koc 290 mg/L 

Photolysis half-life kdp 83 days Half-life 

Aerobic Aquatic Metabolism kbacw 978 days Halfife 

Anaerobic Aquatic Metabolism kbacs 0 days Halfife 

Aerobic Soil Metabolism asm 577 days Halfife 

Hydrolysis: pH 7 0 days Half-life 

Method: CAM 4 integer See PRZM manual 

Incorporation Depth: DEPI 7.6 cm 

Application Rate: TAPP 0.31 kg/ha 

Application Efficiency: APPEFF 1.0 fraction 

Spray Drift DRFT 0.00 fraction of application rate applied to pond 

Application Date Date 01-05 dd/mm or dd/mmm or dd-mm or dd-mmm 

Record 17: FILTRA 

 IPSCND 1 

 UPTKF 

Record 18: PLVKRT 

 PLDKRT 

 FEXTRC 0.5 

Flag for Index Res. Run IR EPA Pond 

Flag for runoff calc. RUNOFF none none, monthly or total(average of entire run) 

 

-Page 110 of 115- 
Appendix F. Federally Listed Species Potentially at Risk from the Proposed Uses of 

Penflufen 

Bird counts by state associated with the highest two exposure scenarios 

Species Counts by State and Generic Taxon

No species were excluded.

Minimum of 1 Acre.

All Medium Types Included

canola, corn for grain, corn for silage or greenchop, corn-popcorn & sweet corn, corn-sweet 

for seed, cotton-all, safflower, sunflower seed-all

AL, AK, AS, AZ, AR, CA, CO, CT, DE, DC, FM, FL, GA, GU, HI, ID, IL, IN, IA, KS, KY, LA, ME, MH, MD, 

MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, MP, an, OA, an, OP, OH, OK, OR, PW, 

Alabama

The Generic Taxon Amphibian has 10 species co-occurring with the indicated crops

The Generic Taxon Bird has 52 species co-occurring with the indicated crops

The Generic Taxon Reptile has 17 species co-occurring with the indicated crops

Arizona

The Generic Taxon Amphibian has 12 species co-occurring with the indicated crops

The Generic Taxon Bird has 47 species co-occurring with the indicated crops

The Generic Taxon Reptile has 2 species co-occurring with the indicated crops

Arkansas

The Generic Taxon Bird has 44 species co-occurring with the indicated crops

California

The Generic Taxon Amphibian has 93 species co-occurring with the indicated crops

The Generic Taxon Bird has 125 species co-occurring with the indicated crops

The Generic Taxon Reptile has 52 species co-occurring with the indicated crops

Colorado

The Generic Taxon Bird has 88 species co-occurring with the indicated crops

Connecticut

The Generic Taxon Bird has 12 species co-occurring with the indicated crops

The Generic Taxon Reptile has 2 species co-occurring with the indicated crops

Delaware

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

The Generic Taxon Reptile has 1 species co-occurring with the indicated crops

Florida

The Generic Taxon Amphibian has 23 species co-occurring with the indicated crops

The Generic Taxon Bird has 252 species co-occurring with the indicated crops

The Generic Taxon Reptile has 95 species co-occurring with the indicated crops

-Page 111 of 115- 
Georgia

The Generic Taxon Amphibian has 24 species co-occurring with the indicated crops

The Generic Taxon Bird has 324 species co-occurring with the indicated crops

The Generic Taxon Reptile has 57 species co-occurring with the indicated crops

Guam

The Generic Taxon Bird has 5 species co-occurring with the indicated crops

The Generic Taxon Reptile has 4 species co-occurring with the indicated crops

Hawaii

The Generic Taxon Bird has 50 species co-occurring with the indicated crops

Illinois

The Generic Taxon Bird has 7 species co-occurring with the indicated crops

Indiana

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

The Generic Taxon Reptile has 3 species co-occurring with the indicated crops

Iowa

The Generic Taxon Bird has 5 species co-occurring with the indicated crops

Kansas

The Generic Taxon Bird has 71 species co-occurring with the indicated crops

Kentucky

The Generic Taxon Bird has 29 species co-occurring with the indicated crops

Louisiana

The Generic Taxon Bird has 31 species co-occurring with the indicated crops

The Generic Taxon Reptile has 5 species co-occurring with the indicated crops

Maine

The Generic Taxon Bird has 10 species co-occurring with the indicated crops

Maryland

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

The Generic Taxon Reptile has 4 species co-occurring with the indicated crops

Massachusetts

The Generic Taxon Bird has 19 species co-occurring with the indicated crops

The Generic Taxon Reptile has 4 species co-occurring with the indicated crops

Michigan

The Generic Taxon Bird has 35 species co-occurring with the indicated crops

The Generic Taxon Reptile has 6 species co-occurring with the indicated crops

Minnesota

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

Mississippi

-Page 112 of 115- 
The Generic Taxon Amphibian has 2 species co-occurring with the indicated crops

The Generic Taxon Bird has 30 species co-occurring with the indicated crops

The Generic Taxon Reptile has 47 species co-occurring with the indicated crops

Missouri

The Generic Taxon Bird has 6 species co-occurring with the indicated crops

Montana

The Generic Taxon Bird has 29 species co-occurring with the indicated crops

Nebraska

The Generic Taxon Bird has 135 species co-occurring with the indicated crops

Nevada

The Generic Taxon Bird has 4 species co-occurring with the indicated crops

The Generic Taxon Reptile has 4 species co-occurring with the indicated crops

New Hampshire

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

New Jersey

The Generic Taxon Bird has 23 species co-occurring with the indicated crops

The Generic Taxon Reptile has 17 species co-occurring with the indicated crops

New Mexico

The Generic Taxon Amphibian has 5 species co-occurring with the indicated crops

The Generic Taxon Bird has 58 species co-occurring with the indicated crops

The Generic Taxon Reptile has 1 species co-occurring with the indicated crops

New York

The Generic Taxon Bird has 63 species co-occurring with the indicated crops

The Generic Taxon Reptile has 22 species co-occurring with the indicated crops

North Carolina

The Generic Taxon Bird has 153 species co-occurring with the indicated crops

The Generic Taxon Reptile has 48 species co-occurring with the indicated crops

North Dakota

The Generic Taxon Bird has 78 species co-occurring with the indicated crops

Northern Mariana Islands

The Generic Taxon Bird has 15 species co-occurring with the indicated crops

Ohio

The Generic Taxon Bird has 8 species co-occurring with the indicated crops

The Generic Taxon Reptile has 5 species co-occurring with the indicated crops

Oklahoma

The Generic Taxon Bird has 220 species co-occurring with the indicated crops

The Generic Taxon Reptile has 1 species co-occurring with the indicated crops

-Page 113 of 115- 
Oregon

The Generic Taxon Bird has 41 species co-occurring with the indicated crops

Pennsylvania

The Generic Taxon Bird has 1 species co-occurring with the indicated crops

The Generic Taxon Reptile has 15 species co-occurring with the indicated crops

Puerto Rico

The Generic Taxon Amphibian has 10 species co-occurring with the indicated crops

The Generic Taxon Bird has 57 species co-occurring with the indicated crops

The Generic Taxon Reptile has 29 species co-occurring with the indicated crops

Rhode Island

The Generic Taxon Bird has 10 species co-occurring with the indicated crops

South Carolina

The Generic Taxon Amphibian has 4 species co-occurring with the indicated crops

The Generic Taxon Bird has 108 species co-occurring with the indicated crops

The Generic Taxon Reptile has 2 species co-occurring with the indicated crops

South Dakota

The Generic Taxon Bird has 79 species co-occurring with the indicated crops

Tennessee

The Generic Taxon Bird has 24 species co-occurring with the indicated crops

Texas

The Generic Taxon Amphibian has 21 species co-occurring with the indicated crops

The Generic Taxon Bird has 309 species co-occurring with the indicated crops

The Generic Taxon Reptile has 11 species co-occurring with the indicated crops

Utah

The Generic Taxon Bird has 23 species co-occurring with the indicated crops

The Generic Taxon Reptile has 1 species co-occurring with the indicated crops

Virgin Islands

The Generic Taxon Reptile has 1 species co-occurring with the indicated crops

Virginia

The Generic Taxon Amphibian has 3 species co-occurring with the indicated crops

The Generic Taxon Bird has 7 species co-occurring with the indicated crops

The Generic Taxon Reptile has 4 species co-occurring with the indicated crops

Washington

The Generic Taxon Bird has 45 species co-occurring with the indicated crops

West Virginia

The Generic Taxon Amphibian has 5 species co-occurring with the indicated crops

Wisconsin

-Page 114 of 115- 
-Page 115 of 115- 

The Generic Taxon Bird has 6 species co-occurring with the indicated crops

Wyoming

The Generic Taxon Amphibian has 1 species co-occurring with the indicated crops

The Generic Taxon Bird has 27 species co-occurring with the indicated crops

Fish and surrogates count by State associated with rice 

Species Counts by State and Generic Taxon

No species were excluded.

Minimum of 1 Acre.

All Medium Types Included

rice

AL, AK, AS, AZ, AR, CA, CO, CT, DE, DC, FM, FL, GA, GU, HI, ID, IL, IN, IA, KS, KY, LA, ME, MH, MD, 

MA, MI, MN, MS, MO, MT, NE, NV, NH, NJ, NM, NY, NC, ND, MP, an, OA, an, OP, OH, OK, OR, PW, 

Arkansas

The Generic Taxon Fish has 15 species co-occurring with the indicated crops

California

The Generic Taxon Amphibian has 31 species co-occurring with the indicated crops

The Generic Taxon Fish has 55 species co-occurring with the indicated crops

Florida

The Generic Taxon Fish has 1 species co-occurring with the indicated crops

Illinois

The Generic Taxon Fish has 2 species co-occurring with the indicated crops

Louisiana

The Generic Taxon Fish has 27 species co-occurring with the indicated crops

Mississippi

The Generic Taxon Fish has 16 species co-occurring with the indicated crops

Missouri

The Generic Taxon Fish has 8 species co-occurring with the indicated crops

Tennessee

The Generic Taxon Fish has 4 species co-occurring with the indicated crops

Texas

The Generic Taxon Amphibian has 3 species co-occurring with the indicated crops