UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON D.C., 20460

PC CODE: 125501
DP BARCODE: 401610

MEMORANDUM DATE: 5/23/2013

SUBJECT: · Ecological Risk Assessment in Support of Registration Review of
Clofentezine

TO: Wilhelmena Livingston, Chemical Review Manager Kevin Costello, Chief (Acting)
Risk Management and Implementation Branch IV
Pesticide Re-evaluation Division

THROUGH: Dana Spatz, Branch Chie:D (

.**ooooo:::::;:~~~~~~~~--**

FROM: Rosanna Louie-Juzwiak, Ris ssessment Process e a Amy Blankinship, Chemist**~** 

# crJames Hetrick, Ph.D., Senior Advisor
Environmental Risk Branch 3
Environmental Fate and Effects Division (7507P)

Nick Mastrota, Ph.D., Wildlife Biologist 

# !Jt""J/t

Ronald Parker, Ph.D., Senior Environmental

### Engin~;r**li.J** Environmental Risk Branch 3
Environmental Fate and Effects Division

This memorandum transmits the preliminary ecological risk assessment for the registration
review of clofentezine (PC Code 125501), an acaricide. Based on currently registered uses and
labeled rates, this preliminary assessment presents the conclusions of potential risks to non-target organisms, including federally-listed species.

The results of this preliminary risk assessment indicate that all outdoor uses of clofentezine can potentially lead to direct adverse effects to listed and non-listed birds and mammals. As birds

serve as surrogates for reptiles and terrestrial-phase amphibians, risk to these taxa is also a possibility. Risk to terrestrial vertebrates is associated with sublethal effects on reproduction and growth that may occur with chronic exposure. Acute risk to terrestrial vertebrates is predicted to be minimal. Use of clofentezine is not expected to pose a risk to foraging (adult) bees; however,
there is a potential for risk to non-listed and listed terrestrial arthropods because of adverse
effects to reproduction and development. Use of clofentezine is not expected to cause direct or2 indirect adverse effects to non-listed or listed fish, aquati c invertebrates, or aquatic plants. Thus,
a “no effect” determination is made for all listed aqua tic organisms.

While the chronic level of concern (LOC) for terr estrial animals is exceede d, there is uncertainty with this screening-level estimate because (1) estimated environmental concentrations (EEC)
did not exceed observed lowest observed advers e effect concentrations (LOAEC) and (2) clofentezine is not persistent in the terrestrial environment, and thus is expected to decline to below toxic levels rather quickly.

A honey bee contact study found that clofentezine is practically nontoxic to adult bees. Based on available acute toxicity data with adult bees, no specific bee acute hazard statement is needed on product labels. Studies with bene ficial beetles have found that cl ofentezine also has low acute toxicity to these species. Howe ver, data published in the open literature show that clofentezine has causes toxicity to eggs and ear ly life-stages of bees and other insects. The available toxicity
data and risk assessment methods do not allow for a precise description of the chronic risk to terrestrial insects. A qualitative evaluation indicates that potential risk of clofentezine use to cause significant brood eff ects in bees is probably small, but the potential for it to cause adverse effects to listed species of terrest rial arthropods cannot be ruled out.

Several lines of evidence indica te that clofentezine has low t oxicity to plants. Limit tests conducted with terrestrial plants found no signifi cant phytotoxicity when plants were treated directly at the maximum application rate. A limit study testing the toxicity of a formulated product indicates that clofentezine is not t oxic to green algae at the solubility limit of clofentezine. Also, clofentezine is routinely applied to a wide variety of plants in greenhouses, orchards, and tree farms without any reported pr oblems with phytotoxicity or plant damage incidents. Finally, the only known toxic mode of action of clofentezine (toxicity to eggs and growth inhibition of early life-stag es of invertebrates) is not rele vant to plants. Therefore, EPA
concludes that use of clofentezine will not pose risk to either terre strial or aquatic plants, and is not expected to harm listed species of plants. Thus, a “no effect” determination is made for all listed plants.

The two major degradates of clofentezine ar e 2-chlorobenzonitrile from direct aqueous photolysis, and 2-chlorobenzoic acid (2-chlorobenzy lidine)hydrazide (AE C593600) from abiotic hydrolysis. Because toxicity data on these de gradation products were not available, acute toxicity to aquatic organisms was estimated ba sed on structural-activity relationships (SAR) using the ECOSAR program. Toxicity estimates i ndicated that these degr adation products are less toxic than that of the pare nt. Therefore, the conclusion is that a risk assessment conducted based on exposure to the parent compound would be protective.

The table below ( Table 1 ) summarizes the risk conclusions fo r direct effects to listed species.3Table 1. Listed Species Risks Associated with Potential Direct Effects Due to the Applications of Clofentezine.Listed Plant TaxonPotential Direct EffectsTerrestrial and semiaquatic plants –monocots and dicotsNo effectAquatic plantsNo effectListed Animal TaxonPotential Direct EffectsAcuteNotesChronicNotesTerrestrial invertebratesYes(see note 1)1.Adverse effects to terrestrial invertebratesare expected to be limited to those thatare exposed as eggs or larval stages.Terrestrial invertebrates exposed as adultsare not expected to be affected.ND2.Based on results from the T-REXmodel, screening-level RQs exceedthe chronic LOC for mammals of allsize classes that eat any food itemsother than fruit, seeds, or pods. Toreduce all of the RQs for chronic riskto listed mammals to less than thechronic LOC, the single applicationrate would need to be reduced to<0.024 lb a.i./A.3.Based on results from the T-REXmodel, screening-level RQs exceedthe chronic LOC for birds that eatplants (short grass or broadleafplants). To reduce all of the RQs forchronic risk to listed birds to lessthan the chronic LOC , the singleapplication rate would need to bereduced to<0.125 lb a.i./A. Theseresults are also applicable for reptilesand terrestrial phases of amphibians.Mammals NoeffectYes(see note 2)Birds NoeffectYes(see note 3)Reptiles NoeffectYes(see note 3)Amphibians NoeffectYes(see note 3)Freshwater fishNoeffect NoeffectFreshwaterinvertebratesNo effectNoeffectMollusksNo dataNo dataEstuarine/marine fish No dataNodataEstuarine/marineinvertebratesNo effect No effect4 At this current stage of the Registration Revi ew process, it is premature to make effects determinations for individual listed species unti l further refinements are conducted. In order to make effects determinations for individual species , useful refinements may include analyses of 1) more detailed, species-specific ecological and biological data; 2) more detailed and accurate information on clofentezine’s use patterns; and 3) sub-county level spatial proximity data for the co-occurrence of potential effects areas and listed species and any designa ted critical habitat. Examples of such refinements are described below.

EFED is currently developing tools that are expe cted to further refine the assessment and are designed to support effects determinations for individual federally list ed species and their designated critical habitats (whe re applicable). Scientific info rmation obtained from the U.S. Fish & Wildlife Service (USFWS), the National Marine Fisheries Service (NMFS), and other reliable sources is being co llated by EFED to address all currently listed species. The information will be stored in an Office of Pesticide Programs Pesticide Registration Information SysteM (PRISM) knowledgebase. The listed species knowledgebase will consist of an information repository that houses biological and behavioral info rmation relevant to individual species ( e.g. , habitat, diet, and life history, including specific temporal and spatial associations) and a document repository that contains supporting documents ( e.g ., USFWS recovery plans) and electronic information ( e.g ., GIS data files). For terrestrial taxa, the biological information relevant to risk quotient (RQ) calculations ( e.g ., diet and body weight) will be used to parameterize exposure estimates to derive speci es-specific RQs using a method consistent with currently used methods in the T-REX and T-HERPS models.

Refinements may also include more detailed analyses of the registered uses and their use patterns that result in LOC exceedances for federally list ed species in the screening-level assessment. The analyses may include more information on wh ere, when, and how clofentezine is used on crops including: fruit trees, nut trees, grapes, Christmas tree plan tations, and ornamental plants. Actual usage data (when availa ble) and national land-cover data sets that indicate potential use sites ( e.g ., national land cover dataset (NLCD), crop data layer (CDL)) may be used to support a more refined analysis of where clofentezine is reasonably expected to be used. Similarly, refinements for the timing of applications and how clofentezine is used may include the analysis of additional usage data, beyond what were av ailable at the time of the screening-level assessment, and a more in-depth ex ploration of agronomic practices.

The U.S. Environmental Protection Agency, along with the U.S. Department of Agriculture (USDA), the U.S. Fish and Wildlife Service (FWS ), and the National Mari ne Fisheries Service (NMFS), have announced the availability of a report developed by the National Academy of Sciences’ National Research Council (NRC) outli ning recommendations on specific scientific and technical issues related to the developmen t of endangered and threatened species risk assessments for pesticides that are compliant with the Endangered Species Act (ESA) and the Federal Insecticide, Fungicide, and Roden ticide Act (FIFRA). The EPA, USDA, FWS and NMFS asked the NRC to consider a range of scientific and technical issues including:

• identifying best available scientific data and information;

• considering sub-lethal, indire ct and cumulative effects;

• assessing the effects of chemical mixtures and inert ingredients;5 • analyzing the effects of pesticid e use through the us e of models;

• incorporating uncertainties in to the evaluations; and

• using geospatial information and datasets thatcan be employed by the agencies in the
course of these assessments.

After reviewing the NRC’s recommendations on th ese scientific and technical issues, the EPA and its federal partners will determine how th ese recommendations can be implemented and incorporated into the scientific approaches for developing listed species ri sk assessments. It is anticipated that any draft guida nce and/or science policies de veloped by EPA and its federal partners as a result of the NRC’s recommendations would be released for public comment prior to implementation.

The refinements based on individu al species data; additional, de tailed usage information, when available; and further recommendations from th e NRC report are expected to help to more accurately identify potential area s of effect and to better inform effects and habitat determinations for listed species and any designated critical habitats. For ex ample, if clofentezine is used when a particular speci es of concern is not present ( e.g ., it is migratory) or is not colocated in space, then risk of potential direct effects to the species may often be precluded. If
LOCs are still exceeded for bi rds (surrogates for terrestrial-phase amphibians and reptiles), mammals, and terrestrial invertebra tes after conducting th e refined analyses, further analyses of the potential spatial and temporal co-occurrence of listed species of conc ern (and any designated critical habitat) may be conducted. The extent of possible refinement in the analyses ofspatial/temporal co-occurrence will largely depend on the scale and quality of the available subcounty level use site ( e.g ., National Land Cover Dataset, Cropland Data Layer) and species
location data

.6 

# Ecological Risk Assessment in Support of the Registration Review of Clofentezine

Clofentezine 1,2,4,5-Tetrazine, 3,6-bis(2-chlorophenyl)-
CAS No. 74115-24-5
P.C. Code: 125501

Prepared by: Nicholas Mastrota, Wildlife Biologist Ronald Parker, Senior Environmental Engineer

Approved by: Dana Spatz, Branch Chief Rosanna Louie-Juzwiak, Risk Assessment Process Leader Amy Blankinship, Chemist James Hetrick, Senior Advisor Office of Chemical Safety and
Pollution Prevention7 TABLE OF CONTENTS

I. Executive Summary ............................................................................................................. ..... 9
A. Purpose of this Assessment .............................................................................................. 9
B. Summary of Effects and Risk Conclusions ...................................................................... 9
II. Problem Formulation ....................................................................................................... 13
A. Introduction .................................................................................................................. .. 13
B. Nature of the Stressor ..................................................................................................... 13
1. Pesticide Type, Class, and Mode of Action ................................................................ 13
2. Physical and Chemical Properties .............................................................................. 14
C. Stressor Source and Distribution .................................................................................... 15
1. Pesticide Use............................................................................................................... 15
2. Pesticide Usage ........................................................................................................... 17
D. Environmental Fate Summary ........................................................................................ 19
1. Clofentezine ................................................................................................................ 1 9
1. Degradation Products of Clofentezine ........................................................................ 21
E. Ecological Effect Summary ........................................................................................... 22
1. Aquatic Effects ........................................................................................................... 22
2. Terrestrial Effects ....................................................................................................... 28
3. Toxicity of Degradation Products ............................................................................... 31
F. Ecosystems Potentially at Risk .......................................................................................... 33
G. Assessment Endpoints .................................................................................................... 33
III. Analysis Plan and Conceptual Model ............................................................................. 35
A. Measures to Evaluate Risk Hypothesis .......................................................................... 35
B. Conceptual Model .......................................................................................................... 35
C. Risk Hypothesis.............................................................................................................. 36
D. Conceptual Diagram ....................................................................................................... 36
IV. Exposure Analysis ............................................................................................................. 38
A. Use Characterization ...................................................................................................... 38
B. Aquatic Fate and Exposure Characterization ................................................................. 38
1. Fate Characterization .................................................................................................. 38
2. Model Input Parameters .............................................................................................. 39
3. Estimated Environmental Concentrations .................................................................. 40
4. Monitoring Data ......................................................................................................... 41
C. Terrestrial Exposure ....................................................................................................... 41
V. Risk Estimates for Non-Target Organisms .......................................................................... 43
A. Aquatic Organisms ......................................................................................................... 43
1. Aquatic Animals ......................................................................................................... 43
2. Aquatic Plants ............................................................................................................. 46
B. Terrestrial Organisms ..................................................................................................... 47
1. Terrestrial Wildlife ..................................................................................................... 47
2. Terrestrial Plants ......................................................................................................... 49
3. Bees and Other Nontarget Terrestrial Arthropods ...................................................... 49
VI. Risk Description and Characterization .......................................................................... 51
A. Risk to Aquatic Organisms ............................................................................................ 51
1. Aquatic Animals ......................................................................................................... 518 2. Aquatic Plants ............................................................................................................. 54
B. Risk to Terrestrial Organisms ........................................................................................ 55
1. Nontarget Terrestrial Vertebrates ............................................................................... 55
2. Terrestrial Arthropods ................................................................................................ 58
3. Terrestrial Plants ......................................................................................................... 58
C. Ecological Incidents ....................................................................................................... 59
D. Uncertainties, Limitations, and Assumptions ................................................................ 59
1. Endocrine Disruption .................................................................................................. 59
2. Uncertainties Related to Data Limitations .................................................................. 60
3. Uncertainty in Risk Conclusions ................................................................................ 61
VII. Risk Conclusions .............................................................................................................. . 62
VIII. References .................................................................................................................... ...... 65
APPENDIX A .................................................................................................................... .......... 67
APPENDIX B .................................................................................................................... .......... 70
APPENDIX C .................................................................................................................... .......... 71
APPENDIX D .................................................................................................................... .......... 72
APPENDIX E .................................................................................................................... .......... 79
APPENDIX F .................................................................................................................... .......... 81
APPENDIX G .................................................................................................................... .......... 839 

### I. Executive Summary

A. Purpose of this Assessment

The purpose of this document is to assess the eco logical risks of the cl ofentezine (PC Code 125501). Clofentezine is an agricultural pesticide used to control mites ( i.e. , an acaricide). It is used for mite control on fruit trees, nut trees, Ch ristmas trees, and ornamental plants grown in greenhouses. This pesticide was first registered in the United States in 1989; thus, it has not been subjected to evaluation under reregistra tion. In 2007, the EFED completed a problem formulation for assessing the ecological risk s of use of clofentezine (USEPA, 2007).

This assessment evaluates risks that clofentezine’s registered uses may pose to federally listed endangered and threatened (listed) species, as we ll as to all other non-ta rget plant and animal (“non-listed”) species. This risk assessment in corporates the available effects data, and most current modeling and risk methodologies, some of which may not have been available at the time when previous clofentezine risk assessments were conducted.

B. Summary of Effects and Risk Conclusions

The results of this preliminary risk assessment indi cate that all outdoor uses of clofentezine have the potential for direct adverse effects to list ed and non-listed birds and mammals. As birds serve as surrogates for reptiles and terrestrial-pha se amphibians, risk to these taxa is also a possibility. Risk to terre strial vertebrates is associated with sublethal effects on reproduction and growth that may occur with chronic exposure. Acut e risk to terrestrial vert ebrates is predicted to be minimal. Use of clofentezine is not expected to pose a risk to foraging (adult) bees; however, there is a potential for risk to listed and non-listed terrestr ial arthropods because of adverse effects to reproduction and development. Use of cl ofentezine is not expect ed to cause direct or
indirect adverse effects to liste d and non-listed fish, aquatic invert ebrates, terrestrial plants, or aquatic plants. Thus, a “no effect” determinatio n is made for all listed aquatic organisms.

Based on the available data, suspended concentrate (SC) formulated products of clofentezine are slightly to practically non-toxic to freshwater fi sh and invertebrates on an acute-exposure basis. The limited solubility of the technical grade activ e ingredient (TGAI) prev ented classification of the acute toxicity, but the TGAI was shown to be nontoxic at concentrations that are close to the aqueous solubility limit. Acute risk quotients (RQs) for fish and aquatic invertebrates were below the EPA’s LOCs for listed and non-listed speci es. Chronic toxicity tests did not find any adverse effects caused by chronic exposure to fish at concentrations up to the solubility limit. Chronic exposure to aquatic invertebrates wa s found to inhibit reprodu ction; however, the noobservable-adverse-effects concen tration (NOAEC) in these studies was greater than EECs, and thus the chronic RQs are all below EPA’s LOC.

For birds and mammals, clofente zine is practically nontoxic on an acute exposure basis. The lack of toxicity and the relati vely low use rate resulted in acu te risk quotients well below the
EPA’s level of concern. Howeve r, chronic studies identified adverse effects to birds and
mammals. Because the NOAEC of these studies were less than the EEC for some types of birds and mammals, the chronic RQs were above the EPA’s LOC (dietary-based RQs 0.08 – 2.08, dose-based chronic RQs 0.07 – 10.83). Specificall y, chronic RQs exceeded the LOC for small10 birds that feed on plant foliage, and for mammals th at feed on plant foliag e or arthropods. Thus, all uses of clofentezine are pr edicted to pose chronic risk to birds, mammals, reptiles, and terrestrial amphibians, and may cau se adverse effects to listed sp ecies of these taxa. While the chronic LOC for terrestrial animals is exceeded, there is uncertainty with this screening-level estimate because (1) EECs did not exceed obser ved LOAECs and (2) clofentezine is not persistent in the terrestrial envi ronment, and thus is expected to decline to below toxic levels rather quickly.

A honey bee contact study found that clofentezine is practically nontoxic to adult bees. Based on available acute toxicity data with adult bees, no specific bee acute hazard statement is currently needed on product labels. Studies with beneficial beetles have f ound that clofentezine also has low acute toxicity to these sp ecies. However, data published in open literature show that clofentezine causes toxicity to eggs and early life- stages of bees and other insects. The available toxicity data and risk assessment methods do not allow for a precise description of the chronic risk to terrestrial insects. A qualitative evaluation indicates that potential risk of clofentezine use to cause significant brood effects in bees is probably small, but the potential to cause adverse effects to listed species of terrest rial arthropods cannot be ruled out.

Because clofentezine is applied only once per year and residues are not very persistent in the environment, chronic effects to te rrestrial animals are not expected to be on a scale that would significantly affect their populations. Therefore indirect effect to endangered animals from loss of ecological services, such as diminished s eed dispersal of plants, are believed to be
discountable.

Several lines of evidence indica te that clofentezine has low t oxicity to plants. Limit tests conducted with terrestrial plants found no signifi cant phytotoxicity when plants were treated directly at the maximum application rate. A limit study testing the toxicity of a formulated product of clofentezine to green algae also found no observable toxi c effects when tested at the high concentration of 100 mg pr oduct/L, with the maximum activ e ingredient concentration assumed to be at the solubility limit (34.2 μg/L). Although other types of aquatic plants may be more sensitive, and testing with other species of aquatic plants would be needed to draw general conclusions for aquatic plants as a group, this test indica tes that clofentezine is not toxic to green algae at the solubility limit of clofentezine. Also, clofentezine is routinely applied to a wide variety of plants in greenhouses, orchards, and tr ee farms without any re ported problems with phytotoxicity or plant damage incidents. Fina lly, the only known toxic mode of action of clofentezine (toxicity to eggs a nd growth inhibition of early life-stages of invertebrates) is not relevant to plants. Therefore, EPA concludes that use of clof entezine will not pose significant risk to either terrestrial or aquatic plants, and is not expected to harm listed species of plants. Thus, a “no effect” determination is made for all listed plants.

The two major degradates of clofentezine ar e 2-chlorobenzonitrile from direct aqueous photolysis, and 2-chlorobenzoic acid (2-chlorobenzy lidine)hydrazide (AE C593600) from abiotic hydrolysis. Because toxicity data on these de gradation products were not available, acute toxicity to aquatic organisms was estimated ba sed on structural-activity relationships (SAR) using the ECOSAR program. Additional informa tion on development and use of the ECOSAR
model is available at: http://www.epa.gov/oppt/newchems/tools/21ecosar.htm. Toxicity estimates11 indicated that the toxicity of th e degradation products would be less than that of the parent. Therefore, the conclusion is that a risk a ssessment conducted based on exposure to the parent compound would be protective.

Conclusions about the potential for clofentezine to cause direct effects to threatened and endangered species of various ta xa are summarized in Table 2. Because of limitations in available toxicity data and assumptions made in the exposure assessments, some uncertainty
exists in the conclusions descri bed here. (see Section VI.C.)12Table 2. Listed Species Risks Associated with Potential Direct Effects Due to the Applications of Clofentezine.Listed Plant TaxonPotential Direct EffectsTerrestrial and semiaquatic plants –monocots and dicotsNo effectAquatic plantsNo effectListed Animal TaxonPotential Direct EffectsAcuteNotesChronicNotesTerrestrial invertebratesYes(see note 1)1. Adverse effects to terrestrial invertebratesare expected to be limited to those that areexposed as eggs or larval stages. Terrestrialinvertebrates exposed as adults are notexpected to be affected.ND2. Based on results from the T-REXmodel, screening-level RQs exceedthe chronic LOC for mammals of allsize classes that eat any food itemsother than fruit, seeds, or pods. Toreduce all of the RQs for chronic riskto listed mammals to less than thechronic LOC, the single applicationrate would need to be reduced to<0.024 lb a.i./A.3. Based on results from the T-REXmodel, screening-level RQs exceedthe chronic LOC for birds that eatplants (short grass or broadleafplants). To reduce all of the RQs forchronic risk to listed birds to lessthan the chronic LOC, the singleapplication rate would need to bereduced to<0.125 lb a.i./A. Theseresults are also applicable for reptilesand terrestrial phases of amphibians.Mammals NoeffectYes(see note 2)Birds NoeffectYes(see note 3)Reptiles NoeffectYes(see note 3)Amphibians NoeffectYes(see note 3)Freshwater fishNoeffect NoeffectFreshwaterinvertebratesNo effectNoeffectMollusksNo dataNo dataEstuarine/marine fish No dataNodataEstuarine/marineinvertebratesNo effect No effect13 

### II. Problem Formulation

A. Introduction

The problem formulation describes the stressor, the conceptual model used to estimate exposure,
and the tools and methods used to assess the potential risk of clofentezine to nontarget organisms. The problem formulation for this a ssessment was originally pr ovided on February 2,
2007 in a memorandum entitled EFED Problem Formulation for Clofentezine Registration
Review , which is part of the Clofentezine Registration Review Summary Document available in
the Clofentezine Docket 1 . The problem formulation in this document represents the original problem formulation modified in response to public comments received on the original version.

B. Nature of the Stressor

1. Pesticide Type, Class, and Mode of Action
Clofentezine (3,6-bis(2-chlor ophenyl)-1,2,4,5-tetrazine; CAS Registry Number 74115-24-5) is the primary chemical stressor to be consider ed in this registration review assessment. Clofentezine belongs to the tetraz ine chemical family of pesticides . The structure of clofentezine is shown in Figure 1. The only ot her acaricide in this chemical family is diflovidazin (3-(2,6- clorophenyl)-6-(2,6-diflu rophenyl)-1,2,4,5-tetrazine; CAS Registry Number 162320-67-4), which is not a registered pesticide in the United States.

Figure 1. Chemical Structure of Clofentezine

Clofentezine is used as a selec tive mite growth regulator by acting as an ovicide. According to information provided by the registrant on the la bel for Clofentezine SC (EPA Reg. No. 66222- 53), clofentezine is active agains t eggs and early life st ages of mites. Yoshida and Fuchs (1989) found that at low doses clofentezine interferes with the development of larval stages of Varroa mites. The Insecticide Resistance Action Committee (IRAC) classifies the mode of action as Group 10, mite growth inhibitors , although the exact site of action is unknown or non-specified (IRAC, 2012). Based on claims made on the produc t labels, clofentezine is not disruptive to beneficial insects and mites even though it ha s good residual activity on European red mites,

1 http://www.regulations.gov/#!docketDetail;D=EPA-HQ-OPP-2006-0240-000314 McDaniel mites, Pacific spider mites, two-s potted spider mites, Eriophyes and yellow spider
mites.

In addition to considering exposure to the parent , two degradation products are expected to be
formed in the environment in si gnificant quantities and therefor e are considered as potential stressors. Degradation of clofentezine in soil and water via aqueous hydrolysis forms 2-
chlorobenzoic acid (2-chlorobenzylidine)hydrazide (AE C593600). Degradation of clofentezine in shallow water via aqueous photolysis forms 2-chlorobenzonitrile. 2- chlorobenzonitrile has
also been observed to form on the fruit and foliage of plants (JMPR, 2007). However, QSAR analysis of these degradation produc ts indicate that they both are significantly less toxic than the parent compound and therefore wi ll not contribute substantia lly as stressors to nontarget organisms (see Section II.E.3.)

2. Physical and Chemical Properties

Clofentezine is a crystalline solid with low a queous solubility and low volatility. The physical and chemical properties of the primary stressor, clofentezine, are shown in Table 3. During the preparation of this assessment, the solubility of clofentezine was revised upward to 34.2 parts per billion (ppb) from the pr eviously reported valu e of “less than 2.0 ppb” based on newly received data 2 . The K
oc value used in earlier EFED assessments was based on the 2.0 ppb solubility concentra tion and has therefore also be en updated for use in this assessment. The Koc value (516.1 L/kg) was calculated using the USEPA EPI (Estimation Programs Interface) Suite program version 4.10.

Table 3. Physical and Chemical Properties of Clofentezine

Common Name Clofentezine

IUPAC and CAS Name: 3,6-bis-(2-chlorophenyl)-1,2,4,5-tetrazine
CAS Registry Number 74115-24-5 Company Code: NC 21314

SMILES Code Clc1ccccc1c1nnc(c2ccccc2Cl)nn1 Empirical Formula C1 4 H 8 C 12 N 4 Molecular Weight, Daltons 303.15 Physical State Crystalline Solid (magenta crystals) Melting Point,  C 179-182 Boiling Point,  C Not applicable Solubility in Water, mgL -1 , 25  C, pH 7 34.2 μg/L
Solubility in Non-aqueous Solvents, 20  C Acetone, 0.5 g/100mL Chloroform, 5 g/100mL Benzene, 0.25 g/100mL

Ethanol, 0.1 g/100mL Hexane, 0.1 g/100mL
Dissociation Constant Not applicable Vapor Pressure, 25  C 9.75 x 10 -10 mm Hg Henry’s Law Constant 1.14 x 10 -8 atm-m 3 mole -1 Log n -octanol/water Partition Coefficient (Log K
ow ) 3.1

2 MRID 48210701Van Meter, D. (2010) Clofentezine: Determination of th e Water Solubility of a Test Substance. Project Number: 11742/6149. Unpublished study prepared by Springborn Smithers Laboratories.15 C. Stressor Source and Distribution

1. Pesticide Use

Clofentezine is a registered active ingredient of agricultural pesticide produc ts used for control of mite pests, including spider mites and the European red mite. It is registered for use on fruit trees (apples, apricots, cherries, nectarines, peaches, pe ars, and persimmons), nut trees (almonds and walnuts), grapes, Christmas trees, and ornamental plants. It is available in three formulated products:

 Apollo 42% Ovicide/Mitici de (EPA Reg. No. 66222-65)

 Apollo SC Ovicide/Mitici de (EPA Reg. No. 66222-47)

 Clofentezine SC Ovicide/Miticide (EPA Reg. No. 66222-53)

All clofentezine products are formulat ed as suspension concentrates.

Clofentezine products are diluted with water a nd applied as a spray ont o foliage. For all crops, only one treatment is permitted per growing seas on, and the maximum application rate is 0.26 lb ai/A. Treatment is recommended to occur at the first sign of mite activity, which is likely to occur early in the growing seas on. Spray is typically applied to foliage, although apple trees may be treated as delayed dormant spray, that is, s hortly prior to the openi ngs of the buds in the spring. Treatment may occur up to the pre-harvest interval, which varies from 10 days for peaches and nectarines (CA only) to 140 days for persimmons. Crop-specific details of application methods are given in16 Table 4.17 Table 4. Use Site and Applicati on Information for Clofentezine

Site Description Products 1 AI Single
Maximum Application Rate (lb/A) Max. Apps/ Crop Cycle PHI 2 (days) Application
Methods Restrictions

Apples Apollo SC 0.26 1 45 Delayed dormant or foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Pears Apollo 42%, Apollo SC 0.26 1 21 Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Stone Fruits: apricot, peach, and nectarine Apollo 42% , Apollo SC 0.26 1 10-21 a Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Cherry Apollo SC 0.26 1 21 Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Grape Apollo 42% , Apollo SC 0.26 1 21 Foliar spray with low or high volume sprayer No aerial application No chemigation
Not in NY Do not apply within 100 ft
of freshwater or estuarine
habitat

Cherry Apollo SC 0.26 1 21 Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Persimmon Apollo 42%, Apollo SC 0.26 1 140 Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Tree Nuts: Almonds
and Walnuts Apollo 42%, Apollo SC 0.26 1 14-30 b Foliar spray with low or high volume sprayer No aerial application No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat

Christmas Trees Apollo SC 0.26 1 N/A Foliar spray with low or high volume sprayer No aerial application No chemigation
Not in CA Do not apply within 100 ft
of freshwater or estuarine
habitat

Forestry trees grown in greenhouses Clofentezine
SC 0.26 1 N/A Low or ultralow volume sprayer, or hand-held sprayer No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat
Ornamental Plants: nonbearing trees, shrubs, vines and herbaceous plants Clofentezine
SC 0.26 1 N/A Low or ultralow volume sprayer, or hand-held sprayer No chemigation Do not apply within 100 ft
of freshwater or estuarine
habitat 1 Apollo 42%: Apollo 42% Ovicide/Miticide (Reg. No. 6 6222-65); Apollo SC: Apollo SC Ovicide/Miticide (Reg. No. 66222-47); Clofentezine SC: Clofentezine SC Ovicide/Miticide (Reg. No. 66222-53) 2 PHI = Pre-harvest interval (number of days pr ior to harvest that the application may occur.) a PHI of 10 days is for California only. b PHI of 14 days is for almonds grown in California only.18 2. Pesticide Usage

EPA’s Biological and Economic An alysis Division (BEAD) provi ded an analysis of nationallevel usage information using state-level usage da ta obtained from various public and proprietary sources (Appendix A). Table 5 prov ides recent estimates of the us age of clofentezine on various crops. Crops with the largest use of clofentezine are almonds, apples, cherries, peaches, and walnuts. Crops with low usage (< 500 lbs A.I.) include apricots, grapes, nectarines, pears, and plums. Clofentezine use is not restricted ge ographically and thus may be used nationwide. States with the greatest usage would be those that greatest pro duction of non-citrus fruits and nuts, which include California, Georgia, Michig an, New York, South Carolina, and Washington.

Table 5. Screening Level Estimates of Agricultural Uses of Clofentezine (125501) (February 17, 2012) 1,2

Crop Lbs. A.I. Percent Crop Treated

Average Maximum

Almonds 3,000 <2.5 5
Apples 1,000 <2.5 10
Apricots <500 <2.5 <2.5

Cherries 1,000 5 10

Grapes <500 <1 <2.5

Nectarines <500 5 10

Peaches 1,000 5 15

Pears <500 5 10

Plums/Prunes + <500 <2.5 <2.5

Walnuts 2,000 5 10

1 All numbers rounded. <500 Less than 500 pounds of active ingredient <2.5 Less than 2.5 percent of crop treated

<1 Less than 1 percent of crop treated

+ Crops not known to be listed on active end use product registrations or as Section 18 emergency exemptions when this report was run

2 SLUA data sources include: USDA-NASS (United States Departme nt of Agriculture's National Agricultural Statistics Service)
Private Pesticide Market Research California DPR (Department of Pesticide Regulation)

Figure 2 below is a map of agricultural pestic ide usage at the Crop Re porting District (CRD) level prepared by BEAD for use in the Environm ental Fate and Effects Division documents. These maps are used to help visualize where the pesticide being considered is most likely to be used and can be helpful in scenario se lection and placing the exposure assessment in context. CRDs are boundaries created by US DA NASS which are aggregates of counties (USDA, 2010). Pesticide usage is displayed as average pounds (for the years 2006-2010) per 1,000 acres of farmland in a CRD to normalize fo r the variation in farmland between CRDs. Farmland acreage was obtained from USDA (2007). Usage is based on private market surveys19 of pesticide use in agriculture (Proprietary Data, 2006-2010). The survey data are limited to the states that represent the top 80-90% of acrea ge for the individual crops; therefore, use may be occurring in regions outside the scope of the survey. CRDs showing no usage of pesticides may be due to either the lack of pesticide use in the region or non- participation in the agricultural surveys. In addition, across the years, there may be variations in the specific crops included in the CRD survey. This may result in a lower annual average for the CRD.

This map displays ratio data (i.e., average pounds per 1,000 acres of farmland) summarized at a very high-level. Readers are strongly cautione d against trying to over interpret the map without examination of the underlying data. Th e underlying data may explain some of the many reasons that a Crop Reporti ng District may have a high va lue for a particular active ingredient such as significant acreage (compare d with the CRD as a whole) of a crop or crops with a high application rate a nd frequency of application

.

Proprietary Data. 2006-2010 USDA, 2006-2010. NASS Crop Reportin g Districts. Online: http://www.ers.usda.gov/briefing/arms/r esourceregions/resourceregions.htm#nass

. USDA, 2007. Census of Agriculture. Online: http://www.agcensus.usda.gov/Pu blications/2007/index.asp

.
Figure 2. Map of clofentezine usage by crop reporting district (2006-2010).20 D. Environmental Fate Summary

1. Clofentezine

Abiotic hydrolysis and direct photolysis in water (clear shallow water) and microbial-mediated degradation are major routes of transformation for clofentezine in the environment. Abiotic hydrolysis is pH and temperature dependent. At 25°C, the hydrolytic half-lives of clofentezine are 10.4 days (pH 5), 1.4 days (pH 7) and 0.18 days (pH 9). The direct photolysis half-life is 8.8 days. Although clofentezine under la boratory conditions appears to be more persistent in aerobic soil (t 1/2 = 4 weeks in clay, 6 weeks in loamy sand a nd 8 weeks in clay loam), abiotic hydrolysis and/or direct photolysis are likely to control the degrad ation of clofentezine in the environment. However, extensive mineralization (i.e., CO 2 formation, up to 56% in ae robic soil after one year)
was found in the aerobic soil metabolism studies. T hus, mineralization is an important route of degradation in the environment. The proportion of radioactivity becoming irreversibly bound to soil increases with time to between approxima tely 30% and 50% of applied radioactivity depending on soil type. Levels of 'bound' radioac tivity further increase af ter establishment of
anaerobic conditions.

Clofentezine mobility in soils is uncertain becau se of the lack of accepta ble data to assess its mobility; however, the soil-TLC data suggests th at clofentezine may have low-to-moderate mobility in soils. Results of a more recent batch-equilibrium adsorption/ desorption study (the currently accepted methodology) was deemed i nvalid because of rapid hydrolysis of clofentezine. Even though mobility in soil data s uggest the potential of cl ofentezine to partition into the sediment phase, hydrolytic and photolytic pr ocesses in the water column are expected to
decrease the amount of clofentezine availabl e for sorption onto the sediment phase. EFED therefore used the USEPA EPI (Estimation Programs Interface) Suite 3 program to estimate the Koc (516.1 L/kg). Clofentezine has low potential to volatilize from soil or water.

Two aquatic metabolism studies, one aerobic and one anaerobic, were completed in 2010 and reviewed by the Canadian Pesticide Manage ment Regulatory Agency (PMRA), (Lentz, 2010a, 2010b). Whole system aerobic and anaerobic aq uatic half-lives were calculated for water/sediment samples collected from two ri vers in the United Kingdom. PMRA-calculated, aerobic whole-system half-life values are 23.0 and 28.9 days for the Taunton River system and Weweantic River system, respectively. PMRA- calculated, anaerobic whole-system half-life values are 44.9 and 33.2 days for the Taunton River system and Weweantic River system, respectively. An additional aerobic aquatic study with two surface water/sediment ditch
microcosms was also conducted in the United Ki ngdom. Aerobic whole-system half-life values were 18.2 and 18.9 days for the ditch water- sandy clay loam sedimentstudy and ditch waterclay loam sediment study, respectively. Studi es submitted on the environmental fate of
clofentezine are summarized in Table 6.

3 http://www.epa.gov/oppt/exposure/pubs/episuite.htm US EPA. [2012]. Estimation Programs Interface SuiteTM for Microsoft® Windows, v 4.10].21 Table 6. Environmental Fate Data from Submitted Studies on Clofentezine

Environmental Fate Study Data Comments References

835.2130 [Abiotic] Hydrolysis Temperature: 25  C Half-lives (days)

1.4 (pH 7) pH and temperature dependent MRID: 47192107
MRID: 00159135

835.2240 [Direct] Photolysis
in Water 8.8 days Dark control corrected
half-life MRID: 00159136
MRID: 00159152

835.2410 Photolysis on Soil 31 days 86% of parent remained after 31 days

835.4100 Aerobic soil
metabolism

835.4200 Anaerobic soil
metabolism Temperature: 25  C Half-lives (days) 4 weeks (clay) 6 weeks (loamy sand) 8 weeks (clay loam)

Qualitative results only Mineralization was high

Biotransformation slows
down under anaerobic conditions; mineralization
is much lower than under
aerobic conditions MRID: 40048101
MRID: 40048102
MRID: 41203701

835.4400 Anaerobic Aquatic
Metabolism Whole-system half-life
values are 44.9 and 33.2 days for two rivers in the United Kingdom PMRA Reviewed Study
(2077909) MRID: 48269302

835.4300 Aerobic Aquatic
Metabolism Whole-system half-life
values are 23.0 and 28.9 days for two rivers in the United Kingdom
Whole-system half-life
values are 18.2 and 18.9days for two watersediment ditches in the United Kingdom PMRA Reviewed Study
(2096105) MRID: 48269301

MRID: 47192116

835.1230 Mobility in Soil Koc: 516.1 (L/kg) Calculated Value EPI Suite Ver 4.10

850.1730 Fish
Bioconcentration BCF: 230x (whole body) During the depuration phase, 93% of
accumulated clofentezine was eliminated, with virtually completely elimination after 3 days. MRID 405522-0122 1. Degradation Products of Clofentezine

The major degradates of clofentezine are 2-chlo robenzonitrile (CAS No. 873-32-5) from direct aqueous photolysis and 2-chlorobenzoic acid (2-chlorobenzylidine)hydrazide (AE C593600) from abiotic hydrolysis. The product 2-chloro benzoic acid (2-chlor obenzylidine)hydrazide ) has
been identified as an abiotic hydrolysis product. The rate of abiotic hydrolysis is pH and temperature dependent. At 25° C, the half-lives of clofentezine decrease with increasing pH (10.4 day at pH 5, 1.4 day at pH 7, and 0.18 day at pH 9). The percentage , as percent of the applied radioactivity, of the hydrolysis product AE C593600 increas es with increasing pH. At the conclusion of 30 days, it accounted 14-23% at pH 5, 38% at pH 7, and 45% at pH 9. The direct photolysis of clofent ezine may involve the hydrolytic product as an intermediate. However, direct photolysis would only be significant in clear, shallow water but not in deep, turbid water. Except for CO 2 , only traces of other degradates we re identified in aerobic soils. See Table 7 below. Degradate struct ures are shown in Appendix B.

Clofentezine is degraded in so ils under aerobic conditions with a half-life of approximately 4, 6 and 8 weeks in the clay, loamy sand and clay loam respectively. Degradation of the parent proceeds via hydrolytic cleavage of the tetrazine ri ng leading to the formation of 2-chlorobenzoic (2-chlorofenzylidine) hydr azide. Further degradation leads to the formation of several other minor metabolites including 2- chlorobenzamide and 2-chlorobe nzoic acid with ultimate
mineralization to CO 2 , substantial amounts of which (up to 50% of the applied compound) were
evolved in the first 6 months from aerobi c soils. The rate of mineralization to CO 2 was drastically reduced under anaerobic conditions and is virtually abse nt in sterile soils indicating that the activity of soil microorga nisms is involved in the degradation of the pesticide in aerobic
soils.

On the surface of treated plants , clofentezine degrades primarily by photolysis, and the only major degradation product formed is 2-chlorobenzonitrile (JMPR 2007).

Table 7. Degradation Products of Clofentezine

Environmental Fate
Process Major Degradates Minor Degradates

Hydrolysis
MRID: 00159135 2-chlorobenzoic acid (2- chlorobenzylidene)hydrazide (M1 or VII) 2-chlorobenzonitrile (M2 or V)

2-chlorobenzamide (M5 or II) Aerobic Aquatic
Metabolism
MRID: 47192116 2-chlorobenzoic-(2-chlorobenzylidene)- hydrazide (compound III, AE C593600) 2,5-bis(2-chlorophenyl)-1,3,4- oxadiazole (NC 12940, compound II)

N',N-bis(2-chlorobenzoyl)-hydrazine (NC 12898, compound IV)

2-chlorobenzoic acid (NC 233, compound V) Anaerobic Aquatic
Metabolism
MRID: 48269302
PMRA: 2077909 2-cholorbenzoic acid

2-chlorobenzoic hydrazone N',N-bis(2-chlorobenzoyl)-hydrazine (NC 12898, compound IV)

2-chlorobenzoic acid (NC 233, compound V) Aerobic Soil Metabolism 2-chlorobenzoic (2-chlorofenzylidine) 2-chlorobenzamide23 MRID: 00159138 hydrazide
2-chlorobenzoic acid Direct Aqueous Photolysis
MRID: 00159136 2-chlorobenzonitrile

2-chlorobenzaldehyde

E. Ecological Effect Summary

1. Aquatic Effects

Table 8 contains the available acu te toxicity data that the EP A used to assess the risks of clofentezine to aquatic animals and plants. Fr eshwater fish serve as a surrogate to assess potential risk to aquatic-phase amphibians as well as fish. Acut e toxicity studies show that clofentezine is not acutely toxic to freshwater fish or invertebra tes at aqueous concentrations up to the solubility limit. Because of the limited sol ubility of clofentezine, testing with the TGAI could not be conducted at much above the solubility limit. Testing at higher concentrations was possible when tests were conducted with a ty pical end-use product (TEP), Apollo® 50 SC, which forms a colloidal suspension in water. Although nominal concentrations were very high, the dissolved component of clofente zine in these studies is believed to be near the solubility limit of 34.2 μg/L, while the remainder of the active ingredient would ex ist as suspended particles. (Measured concentrations of clofentezine repor ted in the study reports are believed to be unreliable because the test solution samples were not filtered or centrifuged before analysis.) While the findings of all three avai lable acute toxicity tests with fish agree in showing that the
LC 50 is greater than the solubility limit of cl ofentezine, the TEP st udy conducted with the rainbow trout using Apollo 50 SC (MRID 40568202) was used as the definitive acute fish toxicity study in this risk assessment because it is the only one of the three studies that was classified as acceptable). This TEP study showed that the 96-hr LC 50 is >24 mg product/L, classifying the product as no more than slightly toxic to fish. The limited solubility prevents
classification of the acute toxic ity of the active ingredient, but the TEP study shows that it does not cause mortality or sublethal effects at concentrations up to the solubility limit.

Three acute toxicity tests are available with th e water flea, a freshwater crustacean. Two studies conducted with the TGAI were classified as suppl emental because the lab failed to test up to the solubility limit of clofentezine (both studies) and failed to filter or centrifuge samples before measuring the test concentrations (MRID 00105919). The TEP study conducted using Apollo 50 SC (MRID 40568203) was used in this risk asse ssment as the definitive acute freshwater invertebrate toxicity study because it is the only one of the three studies that was classified as acceptable). This TEP study with the water flea showed that the 48-hr LC 50 of the product is >100 mg product/L, classifying the product as practic ally nontoxic to freshw ater invertebrates.

In acute aquatic tests conducted with Apollo® 50 SC, the mean measured concentration of the test concentrations far exceeds the solubility li mit of clofentezine. Sin ce there is no indication
that the test concentrations we re filtered before chemical analysis, the reported measured concentrations are believed to represents concen trations of undissolved suspended solids as well as the dissolved component of clofentezine. The c oncentration of dissolved clofentezine in these24 tests was assumed to be at equilibrium at near the solubility limit, and thus the LC 50 values for the active ingredient were expressed as greate r than the solubility limit (>34.2 μg a.i./L).

A toxicity study Selenastrum capricornutum conducted with a formulated product, Apollo 50 SC, found that clofentezine had no significant adverse effects on growth and reproduction of green algae at product concentrations as high as 100 mg product/L (MRID 47200501). This study was classified as supplemental because the test duration (92 hr) was shorter than the recommended duration (96-120 hr), and because the study report was missing some information on methodology, including the photoperiod, the age of the algal inoculum, test vessel fill volumes, and a description of the dilution water. Also, at the higher te st concentrations, cell growth was greatly stimulated. According to the study authors, the stimulation presumably occurred because the parent compound was degr ading into nitrogenous products which added nutrients to the growth medium, similar to fertil izer. As with the acute freshwater invertebrate tests, the concentration of clofen tezine was not expected to exceed the solubility limit, and thus the reported endpoints which exceeded the solubility limit were adjusted to the solubility limit of 34.2 μg ai/L. Despite these shortcomings, this stu dy was sufficient to show that clofentezine is not toxic to green algae up to the solubility limit of clofentezine.

Data are not available on the toxicity of clofent ezine to vascular aquatic plants. However, based on the mode of action of this pesticide ( i.e. , as an acaricide), the lack of phytotoxicity observed in terrestrial vascular plants, the lack of reported plant damage incidents or warnings about phytotoxicity to sensitive plants, adverse effects to aquatic vascular pl ants are not expected.

Table 8. Most Sensitive Acute Toxicity Values for Clofentezine to Aquatic Animals and Plants

Taxonomic Group, Study Type Surrogate Species Toxicity Citation
MRID Acceptability
Classification

Fish

Freshwater fish, Acute study with
TGAI Rainbow Trout ( Oncorhynchus mykiss ) 96-hr LC 50 > 14.6 μg ai/L (No mortality or adverse

effects were observed; highest test level was close to the solubility limit) MRID
40568201 Supplemental 1

Freshwater fish, Acute study with

Apollo 50 SC

(50% AI) Rainbow Trout ( Oncorhynchus mykiss ) 96-hr LC 50 > 24 mg product/L
96-hr LC 50 > 34.2 μg ai/L 2 MRID
40912101 Acceptable

Bluegill Sunfish ( Lepomis macrochirus ) 96-hr LC 50 > 10.1 mg product/L
96-hr LC 50 > 34.2 μg ai/L 2 MRID
00159120 Supplemental

Aquatic Invertebrates

Freshwater
invertebrates with TGAI,
Acute Water flea ( Daphnia magna ) 48-hr LC 50 > 1.15 μg ai/L MRID
40568203 Supplemental 3

Water flea ( Daphnia magna ) 48-hr LC 50 > 0.80 μg ai/L MRID
00105919 Supplemental 4

Freshwater invertebrate, Acute study with

Apollo 50 SC

(50% AI) Water flea ( Daphnia magna ) 48-hr LC 50 > 100 mg product/L
48-hr LC 50 > 34.2 μg ai/L 2 MRID
40568202 Acceptable (for TEP)

Aquatic Plants25 Taxonomic Group, Study Type Surrogate Species Toxicity Citation
MRID Acceptability
Classification

Algae, study with

Apollo 50 SC

(50% AI) Green algae ( Selenastrum capricornutum ) Formulation :
96-hr IC 50 > 100 mg/L NOAEC: 100 mg/L LOAEC: >100 mg/L

Active Ingredient:
96-hr IC 50 > 34.2 μg/L 2 NOAEC: 34.2 μg/L 2 LOAEC: >34.2 μg/L 2 MRID
47200501 Acceptable

1. This study was classified as supplemental because the study failed to establish the NOAEC and did not test to either 100 mg a.i./L or the solubility limit of clofentezine.

2. Results for the active ingredient that were calculate d based on reported measured concentration are not reported here because the analytical analysis is belie ved to have measured undissolved solids suspended in the suspension concentrate formulation as well as th e dissolved component. Instead, endpoints with reported active ingredient concentrations greater than the solubility limit were adjusted to greater than the solubility limit (>34.2 μg a.i./L).

3. This study was classified as supplemental because the study failed to establish the NOAEC and did not test to either 100 mg a.i./L or the solubility limit of clofentezine.

4. This study was classified as supplemental because the test was conducted at a nominal concentration well above the solubility limit of clofentezine, and centrifugi ng or filtering of undissolved test material was not used prior to measurement of the concentration of test material.

Table 9 contains available data on the chronic t oxicity of clofentezine to fish and aquatic
invertebrates. Two studies have been conducted on the effects of clofen tezine on the early life stage of freshwater fish. The first stu dy conducted with the rainbow trout (MRID 42735201)
found no adverse effects when the ac tive ingredient was tested at c oncentrations up to 6 μg ai/L. (Testing was conducted at 6 μg ai/L based on a solubility study conducted in 1985 which erroneously reported the solubility of clofentezine as less than 2 μg/L; however, this study was later found to be invalid and a new solubility stu dy yielded a solubility limit of 34.2 μg/L.) This study was classified as supplemental because the concentration of the solvent use (acetone) was not reported, and a solvent control group was not included in the study. A second study was conducted with the fathead minnow and using the formulated product Apollo® 50 SC (MRID 47192101). This study was conducted using a flow-t hrough system, and results are presented based on the time-weighted average of measured concentrations of the active ingredient. Since clofentezine forms a colloidal suspension in this formulated produc t, the study was able to test higher concentrations than in the TGAI study. This study found no adverse effects on growth, hatching success, or time to hatc h at test concentrations as hi gh as 979 μg ai/L, establishing a
NOAEC at this level.

Four aquatic invertebrate life-cycle studies have been submitted for clofentezine. Deficiencies in
all of these studies resu lted in all being classified as supplemental. However, the study submitted which tested the toxicity of the TGAI to Daphnia magna (MRID 42523901) is adequate as a limit test because it demonstrates that clofentezine w ould not cause chronic toxicity to this species at con centrations expected in natural water. This test found no chronic effects were caused by a single test concentration of 26.2 μg ai/L, wh ich is close to the solubility limit of clofentezine at pH 7 (34.2 μg/L). Anothe r life-cycle test was recently submitted which tested the chronic toxicity of the TGAI to the mysid ( Americamysis bahia ), a saltwater26 crustacean (MRID 48342701). This study indicates that the mysid is more sensitive to
clofentezine than Daphnia magna . Female reproduction was significantly impaired at concentrations as low as 3.6 μg a.i./L, whereas gr owth and survival were not adversely affected at any test concentration. These results suggest that the toxic mode of action in the target organisms, i.e. , toxicity to eggs and early growth stages, may also resu lt in similar toxicity to some aquatic invertebrates.

In addition to the TGAI studies, two submitted lif e-cycle studies and one open literature study provides information on the chroni c toxicity to the water flea ( Daphnia magna ) of Apollo 50 SC, a suspension containing 43.5% clof entezine. Both of these studi es were conducted according to the OECD test guideline fo r testing reproduction with Daphnia sp. (Guideline No. 211), which differs from the comparable EPA test guideline (850.1300), and one study (MRID 47192117) had numerous guideline deviations. Thus, bot h of the submitted life-cycle studies were classified as supplemental. Both of these st udies found that reproducti on was a more sensitive chronic endpoint than growth or survival. One study (MRID 47192117) was deficient because solubility challenges made the exposure concentrations uncertain, measured concentrations in aged samples were highly variable, and the study failed to establish an NOAEC for reproduction. This study found that all test concentrations significantly reduced the number of offspring produced per female. Percent re ductions (relative to the contro l) ranged from 8.25% at 0.10 mg product/L to 17.5% at 15 mg product/L. A s econd study (MRID 47192102) had a similar setup to the first except that the test vessels containe d sediment, the test wa s conducted under static
conditions rather than under static-renewal c onditions, and the test material was applied to overlying water at either Day 0 or at Day 6. Reproduction was agai n the most sensitive endpoint. When the test material was applied on Day 0, si gnificant reductions in offspring produced per
female were observed at all te st levels. Percent reductions ra nged from 14.6% at 0.275 mg product/L to 19.2% at 2.65 mg product/L. As the resu lts of this study were similar to the results of the study without sediment, the presence of sediment did not appe ar to substantially affect the reproductive toxicity of clofentezine to Daphnia magna . The study without sediment (MRID 47192117) tested lower test concentrations than did the study with sediment, and thereby established the lower LOAEC for reproductive to xicity of 100 μg product/L, or 44 μg a.i./L.
None of the studies established a NOAEC.

For chronic risk assessment, the repr oductive LOAEC of 44 μg a.i./L for Daphnia magna (MRID 47192117) was selected as the e ndpoint to assess chronic risk to freshwater invertebrates, and the NOAEC of 1.7 μg/L (MRID 48342701) was select ed to assess chronic risk to saltwater
invertebrates.

Table 9. Chronic Toxicity of Cl ofentezine to Aquatic Animals

Taxonomic Group, Study Type Surrogate Species Toxicity Citation
MRID Acceptability
Classification

Fish
Freshwater Fish, Early Life-Stage Rainbow Trout ( Oncorhynchus mykiss ) NOAEC: 6 μg ai/L LOAEC: >6 μg ai/L MRID
42735201 Supplemental 1

Freshwater fish, Early Life-Stage with Apollo 50 SC

(50% AI) Fathead Minnow ( Pimephales promelas ) NOAEC: 979 μg ai/L LOAEC: >979 μg ai/L MRID
47192101 Acceptable27 Taxonomic Group, Study Type Surrogate Species Toxicity Citation
MRID Acceptability
Classification

Freshwater Invertebrates

Freshwater invertebrates, Life-Cycle with TGAI (99.8% purity) Water flea ( Daphnia magna ) NOAEC: 26.2 μg ai/L LOAEC: >26.2 μg ai/L MRID
42523901 Supplemental 2

Freshwater invertebrates, Life-Cycle study with Apollo 50 SC

(50% AI) Water flea ( Daphnia magna ) Survival NOAEC: 15 mg product/L (6.5 mg ai/L) LOAEC: >15 mg/L (>6.5 mg ai/L)

Reproduction NOAEC: <100 μg product/L (<44 μg ai/L) LOAEC: 100 μg product/L (44 μg ai/L) (Reduced number of offspring per female ; 8.25% reduction at lowest test level)

Growth NOAEC: 100 μg product/L (44 μg ai/L) LOAEC: 350 μg product/L (150 μg ai/L) (Reduced length) MRID
47192117 Supplemental 2

Freshwater invertebrates, Reproduction study with Apollo 50 SC (50% AI) Water flea ( Daphnia magna ) Reproduction NOAEC: 0.12 mg product/L (0.06 mg ai/L) LOAEC: 1.2 mg/L (0.60 mg ai/L) (Reduced number of offspring) Eco Ref #
12662
Barber and

Barrett (1993) Qualitative

Freshwater invertebrates, Life-Cycle study,
water with sediment system with Apollo
50 SC (50% AI) Water flea ( Daphnia magna ) Survival NOAEC: 2.50 mg product/L (1.04 mg ai/L) LOAEC: >2.50 mg product/L (>1.04 mg ai/L)

Reproduction
NOAEC: < 0.275 mg product/L (<0.114mg ai/L)
LOAEC: 0.275 mg product/L (0.114 mg ai/L) (Reduced number of offspring when exposed to < 24-hr old neonates)

Growth
NOAEC: 2.50 mg/L MRID
47192102 Supplemental 328 Taxonomic Group, Study Type Surrogate Species Toxicity Citation
MRID Acceptability
Classification (1.04 mg ai/L)
LOAEC: >2.50 mg/L (>1.04 mg ai/L)
Saltwater Invertebrates

Estuarine/marine

invertebrates,

Life-Cycle Mysid shrimp (Americamysis bahia) Survival NOAEC: 29 μg ai/L LOAEC: >29 μg ai/L

Reproduction NOAEC: 1.7 μg ai/L LOAEC: 3.6 μg ai/L (Reduced number of offspring per female) MRID
48342701 Supplemental 4

1. This study was classified as supplemental because a solvent control was not included in the study design, the solvent concentration was not reported, and the stud y report lacked reporting of sublethal effects.

2. This study was classified as supplemental because the study did not identify the NOAEC and LOAEC for clofentezine, the amount of disolved AI in the test solutions was uncertain, and the control mortality was excessive (12.5%).

3. This study was classified as supplemental because it was conducted according to the protocol of OECD Guideline 202, which deviates significantly from th e OSPP Guideline for freshwater invertebrate life-cycle testing, 850.1300. Furthermore, the study failed to establish an NOAEC for reproductive effects.

4. This study was classified as supplemental because the diluter system delivered inconsistent concentrations of active ingredient during the study. Results ar e based on time-weighted average concentrations.

Barber and Barrett (1993) conducte d a study to test their hypothesis that the chronic toxicity to Daphnia magna exhibited by clofentezine products formul ated as suspension concentrate is the consequence of particles in the formulated product causing physical interference with filter feeding rather than the result of intrinsic toxi city of the active ingredient. They tested the reproductive response of Daphnia magna when exposed to three conc entrations of Apollo 50 SC (50% clofentezine), concentra tions of inert polyvinyl toluene (PVT) latex beads that were equivalent to the Apollo 50 SC concentrations in terms of particle concentrations, and a formulated blank (Apollo 50 SC form ulation without the active ingred ient) at a rate equivalent to the highest test concentration. The concentra tions of Apollo 50 SC tested were 0.12, 1.2, and 12 mg/L, which is equivalent to 0.060, 0.60, and 6.0 mg ai/L. The result showed reproduction performance was not significantly affected (relat ive to the control) by th e formulated blank, but was significantly reduced by both the Apollo 50 SC and the PVT bead treatments. The NOAEC for Apollo 50 SC treatment was 0.12 mg product/ L (0.06 mg ai/L). The reproductive response of Daphnia magna in this study was less sensitive to Apo llo 50 SC in this study than a life-cycle study submitted to the EPA (MRID 47192117) in th at the NOAEC and LOAEC were greater, although the dose-response of the number of offspring per female were similar in both studies. For example, MRID 47192117 found an 8.25% reduction in this endpoint at a concentration of 0.044 mg ai/L, and this study found a 9.8% reduction at the slightly high er concentration of 0.060 mg ai/L.

Barber and Barrett (1993) found that exposure of Daphnia magna to supposedly inert PVT latex beads also caused reductions in reproductive pe rformance. The reduction in number of offspring29 produced per adult was generally similar in test so lutions of Apollo 50 SC and mixtures of water and latex beads with identical particular con centrations (Table 10). The reproductive response was similar between comparable treatments with the exception that the reduction in offspring production was somewhat greater in the latex bead mixture than the Apollo 50 SC at the highest particular concentration (3.7 x 10 9 L -1 ). According to the study aut hors, this similarity in the reproductive responses “suggests that the effect of Apollo 50 SC was not due to any intrinsic toxicity of the formulation, but rather a conseque nce of its particular concentration.” This may explain why reproductive toxicity was observed in daphnids exposed to the SC formulated product, but not when exposed to technical grade clofentezine.

Table 10. Comparison of reproductive response of Daphnia magna exposed to Apollo 50 SC and PVT latex beads with identical particle c oncentrations (from Barb er and Barrett, 1993)

Particle
Concentration (particles/L) Product
Concentration (mg/L) AI Concentration (mg ai/L) Number of Offspring per
Adult Percent Change in No. Offspring/Adult Apollo 50
SC Latex
beads Apollo 50
SC Latex
beads
Formulated blank 0 0 35.8 35.8 -- --
3.7 x 10 7 0.12 0.06 32.3 33.8 -9.8 -5.8
3.7 x 10 8 1.2 0.60 31.4 31.9 -12.6 -10.9
3.7 x 10 9 12 6.0 29.7 23.0 -17.1 -35.9

2. Terrestrial Effects

Table 11 presents the acute toxicity data that the Ag ency used to assess the risk of clofentezine to terrestrial animals and plants. Birds act as surrogates for reptiles and terrestrial-phase amphibians when data on those species are not ava ilable. Acute oral and s ubacute dietary studies
with the northern bobwhite and ma llard all showed that clofentezi ne has low acute toxicity to birds. These studies classify cl ofentezine as practically nontoxic to birds. Acute toxicity studies with mammals show that clofentezine is prac tically nontoxic to mammals on an acute basis. Studies on dermal and inhalation toxicity in mammals found no mortality at the doses tested, indicating low acute toxicity th rough these exposure routes (Toxic ity Category III or IV).

An acute contact test with adult honey bees determined the LD 50 to be >1500 mg a.i./L. This study was classified as supplemental because exposu re was expressed as the concentration of the solution sprayed onto the bee, rath er than the amount of active ingredient app lied per bee, per the EPA test guideline. Nevertheless, this study is sufficient to show that use of clofentezine products is expected to pose minimal hazard to a dult bees from acute contact exposure. Also, an available acute oral toxicity honeybee study determined the acute oral toxicity of clofentezine to be >20 μg/bee. Based on the classification scheme used by the EPA for the acute contact studies, this toxicity level w ould classify clofentezine as practically nontoxic to bees.

Yoshida and Fuchs (1989, Eco Ref. No. 154863) provides additional information on the developmental toxicity of clofentezine to the hon ey bee. In one test, the authors exposed the
bees in the 5 th instar (L5) stage with topi cal applications of 10μl clofen tezine solutions, with test concentrations ranging from 0.05 to 500 μg/bee. Failure of the larvae to seal the cell was used as30 a measure of mortality. Elevated levels of mort ality were observed at treatment concentrations of 50 μg a.i./bee and greater. High levels of abnormal pupa development (over 40%) were observed at concentrations of 25 μg a.i./bee a nd greater. This test es tablished an NOAEL of 5 μg a.i./bee for toxicity from acute contact exposur e. In a second bee larvae feeding study, pollen mixtures, containing 1.0 to 1000 mg a.i./kg clofent ezine were fed to larvae bees of nucleus colonies. Bee larvae were in various stages of development from L1 to L5, and were grouped into three groups (L1 and L2, L3 and L4, and L5 ) to measure effects with exposure to various developmental stages. In all developmenta l groups, abnormal bee pupas were observed in groups fed pollen with a clofentezine concentr ation of 1000 mg a.i./kg. Results on mortality were uncertain because no statistical analyses we re conducted, but mortality of bees exposed at the L1 level appeared to be elev ated at clofentezine concentrati ons of 10 mg a.i./kg and greater. Based on mortality, the NOAEL for the f eeding study was 1.0 mg a.i./kg pollen.

One submitted report (MRID 471921-22) and two papers published in the open literature (Samsoe-Peterson, 1993, Olszak, 1999) provide further information on the toxicity of clofentezine to terrestrial beetles (Order Coleoptera). MRID 471921-22 found no significant adverse effects on egg survival , larvae survival, or pupae emergence in the ladybird beetle ( Coccinella septempunctata ) when they were exposed to 100 and 200 g a.i./ha, which corresponds to 0.089 and 0.18 lb a.i. /A, respectively. The spray volumes used were 500 and 1000 L/ha, which are equivalent to 54 and 110 gal/A, respectively. Olszak (1999) studied the toxicity of clofentezine and 29 other pesticides to another ladybird beetle, Adalia bipunctata . An immersion study using 0.027% (270 ppm) concentration of clofen tezine caused relatively low levels of mortality (0-15%) of various developmental stages from L 1 to adult. Clofentezine exposure caused greater effects on reproduction. When eggs were immersed, percent hatch ranged from 76.9 % for 1-day-old eggs to 45.0% for 3-day-old eggs. When females were immersed, egg production was approximately 300 eggs/female, compared to approximately 650 eggs/female in the control. Beetles were also reared on leaves which had been treated with a 0.027% clofentezine solution and allowed to age for 2 hours to 21 days. Exposure of the second
instar resulted in 0% to 47% mo rtality, and exposure to the fort h instar resulted in 0% to 37% mortality. Samsoe-Peterson (1993) studied the effects of Apo llo 50 SC on the survival and reproduction of the rove beetle, Aleochara bilineata . The beetles were sprayed with a
concentration of clofentezine of 0.02% at a rate of 6 μl/cm 2 , which the authors claim is equivalent to exposure to spray at the maximum application rate. The exposure resulted in no mortality of adults and no si gnificant reduction in egg producti on, but caused a 28% reduction in percent hatching of eggs re lative to the control. Together these papers show that clofentezine is not toxic to adult beetles, but is toxic to eggs and early life-stages. One study is available on the phytotoxicity of cl ofentezine. In a Tier 1 vegetative vigor study with the formulated product Apollo 50 SC, a pplication of clofentezine at the maximum application rate of 0.26 lb a.i./A resulted in no observable adverse effects to 4 dicot species and 2 monocot species (MRID 47192103). This indicates that foliar exposure to clofentezine is not toxic to emerged plants at envir onmentally-relevant concentrations . Toxicity related to effects on seed germination and plant emergence is unknown.31 Table 11. Acute Toxicity of Clof entezine to Terrestrial Species

Taxonomic

Group, Study Type Surrogate Species Toxicity (expressed as AI) Citation
MRID Acceptability
Classification

Birds 1

Birds 1 , Acute Oral Bobwhite quail ( Colinus virginianus ) LD 50 > 7500 mg a.i./kg-bw MRID
00105913 Acceptable

Mallard ( Anas platyrhynchos ) LD 50 > 3000 mg/kg-bw MRID
00105914 Acceptable

Birds 1 , Subacute Dietary Bobwhite quail ( Colinus virginianus ) LC 50 > 19,900 mg/kg-diet MRID
00159117 Acceptable

Mallard ( Anas platyrhynchos ) LC 50 > 20,700 mg/kg-diet MRID
00159118 Acceptable

Mammals Mammals, Acute
Oral Laboratory rat ( Rattus norvegicus ) LD 50 > 3230 mg a.i./kg-bw MRID 00159071 Acceptable (Minimal) Mammals, Acute Oral, with 80% wettable powder

formulation Laboratory rat ( Rattus norvegicus ) LD 50 > 4000 mg a.i./kg-bw MRID 00105904 Acceptable (Minimal)

Mammals, Acute Oral, with 50% wettable powder

formulation Laboratory rat ( Rattus norvegicus ) LD 50 > 5000 mg/kg-bw
LD 50 > 2500 mg a.i./kg-bw MRID 00105903 Acceptable (Guideline)

Mammals, Acute Inhalation, 80% wettable powder

formulation Laboratory rat ( Rattus norvegicus ) LC 50 > 11.35 mg/kg-bw
LC 50 > 9.08 mg a.i./kg-bw MRID 00159072 Acceptable (Minimal)

Mammals, Acute Dermal, Apollo
SC formulation (42% a.i.) Rabbit LC 50 > 20,050 mg/Kg-bw
LC 50 > 16,040 mg a.i./Kgbw MRID 00105905 Acceptable (Minimal)

Beneficial Insects

Bee, acute contact Honey bee ( Apis mellifera ) LD 50 (contact) > 1500 mg a.i./L MRID 00159121 Supplemental 2

Bee, acute oral Honey bee ( Apis mellifera ) LD 50 (oral) > 20 μ g/bee MRID 00159121 Supplemental (Nonguideline) Beneficial insect, with Apollo® 50 SC (51.7% a.i.) Ladybird Beetle ( Coccinella
septempunctata ) LC 50 > 200 g a.i./ha NOAEC: 200 g a.i./HA MRID 47192122 Supplemental (Nonguideline)

Terrestrial Plants

Terrestrial Plants, Tier 1 Vegetative Vigor with Apollo 50 SC (49.8% a.i.) Dicots (carrot, cucumber, pea, and canola) IC 25 : >0.26 lb a.i./A
NOAEL: 0.26 lb a.i./A
LOAEL: >0.26 lb a.i./A MRID 47192103 Supplemental 3

Monocots (chufa and oat) IC 25 : >0.26 lb a.i./A
NOAEL: 0.26 lb a.i./A
LOAEL: >0.26 lb a.i./A 1. Birds represent surrogates for te rrestrial-phase amphibians and reptiles. 2. This study was classified as s upplemental because the acute contact LD 50 was expressed as a concentration (mg/L) rather than the amount of a.i. per bee. 3. This study was classified as supplemental because it tested only six species (4 dicots and 2 monocots) and did not measure survival or plant height.32 Table 12 provides results of chronic toxicity tests conducted with birds and mammals. The northern bobwhite was the most sensitive bird speci es. A dietary concentration of 90 mg a.i./kg significantly reduced embryo viab ility, establishing the NOAEC at 30 mg a.i./L. For mammals, a rat 2-generation reproduction te st yielded the lowest chronic NOAEL. A dietary concentration of 500 mg a.i./kg resulted in decreased body wei ght and food consumption in the parents, and decreased pup weight in both the F1 and F2 ge nerations. The NOAEL was established at 50 mg
a.i./L.

Table 12. Chronic Toxicity of Clof entezine to Terrestrial Species

Taxonomic

Group, Study Type Surrogate Species Toxicity (expressed as AI) Citation
MRID Acceptability
Classification

Birds 1

, Reproduction Northern bobwhite ( Colinus virginianus ) NOAEC: 30 mg a.i./kg-diet LOAEC: 90 mg a.i./kg-diet (reduced embryo viability) MRID
42776101 Acceptable

Mallard ( Anas platyrhynchos ) NOAEC: 270 mg a.i./kg-dietLOAEC: >270 mg a.i./kgdiet MRID
42776102 Acceptable

Mammals, 2-

Generation Reproduction Laboratory rat ( Rattus norvegicus ) Parental NOAEC: 50 mg/kg diet LOAEC: 500 mg/kg diet (decreased body weight gain and food consumption)

Reproduction NOAEC: 1000 mg/kg diet LOAEC: >1000 mg/kg diet

Developmental NOAEC: 50 mg/kg diet LOAEC: 500 mg/kg diet (decreased pup weight) MRID 4439914 6 Acceptable

1. Birds represent surrogates for te rrestrial-phase amphibians and reptiles.

3. Toxicity of Degradation Products

The two major degradates of clofentezine are 2-chlorobenzonitrile and 2-chlorobenzoic acid (2- chlorobenzylidine)hydrazide (AE C593600). Photolysis of clofentezine forms 2- chlorobenzonitrile in soil and shallow water, and on plant surfaces. Hydrolysis of clofentezine forms 2-chlorobenzoic acid (2-chlorobenzylidene) hydrazide (AE C593600) in soil and water.
Transformation of clofentezine into both of thes e products involves cleavage of the triazine ring in the center of the molecule. As this substantially changes the shape of the molecule, these products would not likely retain the ovicidal activity of the pa rent compound. However, they may have toxicity through other mechanisms.

Because no studies on the toxic ity of AE C593600 are availa ble, the ECOSAR (ver. 1.0) program was used to estimate toxicity of this compound to aquatic organisms based on quantitative structural-activity re lationships (QSAR). Table 13 presents the estimated acute and chronic toxicity threshold values based on rela tionships with hydrazines and amides, and based33 on relationships with all uncharged compounds (neutral organics). The predicted toxicity of this degradation product is less than that of the parent compound with the exception of the predictions for toxicity to alg ae based on hydrazines. Except for green algae, conversion of the some of the parent compound to the degrada tion product would decrease the overall hazard to nontarget organisms, compared to if the applie d active ingredient remained as the parent compound. Thus, because the terrestrial and aq uatic risk assessments assumed 100% of the applied active ingredient remained as the parent compound, the risk assessments are protective. Any conversion of the parent compound to the de gradation product would only reduce risk, with the possible exception of risk to algae if the ECOSAR predic tions based on hydrazines are

correct.

Table 13. Predicted Toxicity of the Degrad ation Product AE C593600 to Aquatic Organisms Based on Quantitative –Structural Relationships.

Organism Duration Endpoint Predicted Toxicity (μg/L) Hydrazines Amides Neutral Organics Acute Toxicity
Fish 96-hr LC 50 344 3,320 16,800 Daphnid 48-hr LC 50 7,230 2,970 11,400 Green Algae 72-96 hr EC 50 0.0549 274 8,470 Chronic Toxicity Fish chronic NOAEC 26 20 1,540 Daphnid chronic NOAEC 65 39 1,330 Green Algae chronic NOAEC 0.0137 490 3,910

ECOSAR appears to predict AE C593600 may have very high toxicity to green algae based on the toxicity of hydrazine (N 2 H 4 ). Hydrazine, without a carbo xyl group or any other functional groups attached, is highly t oxic to green algae (144-hr EC 50 0.041 μg/L); however,
semicarbazides which are substituted with vari ous functional group have been found to be generally much more toxic to green al gae by 5 to7 orders of magnitude (EC 50 range from 2.5 to 190 mg/L) (Clements 1996). Also, as indicated by the predicted results in Table 13, amides are generally much less toxic to algae. Because AE C593600 is hydrazide, making it an amide as well as a hydrazine, and because it has two chloro -phenyl functional groups attached, we do not believe that the predictions of high toxicity to green algae based on simple hydrazine are appropriate for predicting the toxicity of this compound. We expect th e toxicity of AE C593600 to be closer to the SAR prediction made based on amides, 490 μg/L. Thus, we do not expect AE C593600 to be more toxic to algae than the parent , and formation of this degradation product is not expected to pose a risk to a quatic plants above what is pred icted by the curren t aquatic risk

assessment.

ECOSAR (ver. 1.0) was also used to estimate toxicity of 2-ch lorobenzonitrile to aquatic organisms. By comparing this compound to similar neutral organics, ECOSAR predicts relatively low acute and chronic toxicity for all ev aluated aquatic animals and plants (Table 14). Toxicity of this degradation produc t is therefore expected to be much less than that of the parent. As a check of the predictive ability of ECOSAR for compoun ds related to clofentezine, ECOSAR was used to predict the aquatic toxicity of clofentezine itself, and these predictions were compared to the measured toxicity values. ECOSAR pred ictions of clofentezine were based on all uncharged compounds (neutral organics ). All predicted acute and chronic toxicity thresholds were well above the solubility limit of clofentezine (34.2 μg/L). The predictions34 therefore agreed with the acute t oxicity measurements for fish a nd aquatic invertebrates, and the measured toxicity for green algae, in predicting no observable toxicity at concentrations up to the solubility limit. ECOSAR faile d to predict the chronic toxic ity related to reproductive and developmental endpoints observed in freshwater a nd saltwater invertebrates. This is likely
because related chemicals with this specific ovicide mode of action were not present in the set of chemicals used to develop ECOSAR.

Table 14. Predicted Toxicity of the Degradation Product 2-Chlorobenz onitrile to Aquatic Organisms Based on Quantitative –Structural Relationships.

Organism Duration Endpoint Predicted Toxicity (mg/L) Neutral Organics Acute Toxicity
Freshwater Fish 96-hr LC 50 73.0
Saltwater Fish 96-hr LC 50 100 Daphnid 48-hr LC 50 42.3 Mysid 96-hr LC 50 63.8 Green Algae 96 hr EC 50 21.7 Chronic Toxicity Freshwater Fish 30-days NOAEC 7.70
Saltwater Fish chronic NOAEC 11.8 Daphnid chronic NOAEC 5.05 Mysid chronic NOAEC 5.22 Green Algae chronic NOAEC 8.57

F. Ecosystems Potentially at Risk

Ecosystems potentially at risk from the use of clofentezine include th e orchards, vineyards, nurseries, and tree farms to which it is direc tly applied, and nearby te rrestrial and aquatic ecosystems. Ecological recepto rs are both terrestrial and a quatic nontarget organisms that inhabit or move through these ecosystems. Terrestri al ecosystems which may be at risk are those that may be exposed by direct application of the pesticide and those in ad jacent areas which may be exposed from spray drift. Terrestrial animal s and plants that live in or feed in exposed habitats may be at risk. Aquatic ecosystem s that may be exposed include ponds, streams, wetlands, and other water bodies receiving runoff and/or spray drift from applications to agricultural sites. As clofentezine is used in coastal locations, aquatic ecosystems potentially at risk include salt marshes and estuaries. Aquatic organisms potentially at risk include fish, aquatic invertebrates, an d plants living in the wa ter column and sediment.

G. Assessment Endpoints

Assessment endpoints include reduced survival of individuals or reproduct ion within populations and/or adverse effects to communities. Orga nisms potentially exposed include terrestrial and aquatic plants and animals. Potential effects are determined through testing of surrogate representatives within those taxonomic groups, or from other related taxonomic groups. Assessment endpoints and toxicity data used to evaluate the as sessment endpoints are identified
in Table 15.35 Table 15. Summary of Assessment Endpoints and M easures of Effects for Screening Level Risk
Assessment of Clofentezine

Assessment Endpoint Measurement Endpoint

1. Survival, reproduction, and growth of birds (Birds also serve as surrogates for reptiles and terrestrial phase amphibians in that birds are generally more sensitive than species from these other taxonomic groups.) •Acute oral LD 50 values, subacute 5-d dietary LC 50 values

•Avian reproduction study NOAEC

2. Survival, reproduction, and growth of mammals •Acute oral mammalian LD 50 values

•Mammal 2-generation reproduc tion study NOAEC or NOAEL
3. Survival and reproduction of freshwater fish and
invertebrates (Fish also serve as surrogates for aquatic phase amphibians because fish are generally more sensitive than amphibians) •Freshwater fish 96-h LC 50 and early life-stage NOAEC

•Freshwater invertebrate 48-h EC 50 and life cycle NOAEC

4. Survival and reproduction of estuarine/marine fish and
invertebrates •Estuarine/marine fish 96-h LC 50 and early life -stage NOAEC*

•Estuarine/marine invertebrate 96-h LC 50 (clofentezine) and life cycle NOAEC*

*Currently, no acute or reproducti on study using clofentezine has
been submitted. Without these data, freshwater data could be used as surrogate for these tests.
5. Perpetuation of non-target terrestrial plants (crops and non-crop species) •Monocot and dicot seedling emergence EC 25 and NOAEC, or EC 05 (clofentezine TEP) *

•Monocot and dicot vegetative vigor EC 25 and NOAEC, or EC 05 (clofentezine TEP) *

* Currently, no terrestrial plant st udy using clofentezine TEP has
been submitted. Without terrestri al plant data, assumptions of sensitivity would be made based on mode of action and other
available information.

6. Survival of beneficial in sect populations (Terrestrial invertebrates are represented by the honey bee) •Honey bee acute contact LD 50 *

* Various effects levels on toxicity to eggs and larval stages from studies published in the open litera ture are also considered in characterizing risk to beneficial insects.
7. Maintenance and growth of aquatic plants from standing crop or biomass •Aquatic plant growth and biomass 96-h EC 50 * •Aquatic plant growth a nd biomass 96-h NOAEC or EC 05 *

*Currently, no aquatic plant stud y using clofentezine has been submitted. Without aquatic plant data, assumptions of sensitivity
would be made based on mode of action and other available
information.

LD 50 : Lethal dose to 50% of test population
LC 50 : Lethal concentration to 50% of the test population
EC 50 : median effect concentration is the con centration that results in a sp ecific effect (e.g., immobilit y, emergence) to 50% of t he exposed test population
EC 05 and EC 25 : the concentration that results in a specific effect to 5% and 25%, respec tively, of the exposed test population.
NOAEC = No observed adverse effect concentration36 

### III. Analysis Plan and Conceptual Model

A. Measures to Evaluate Risk Hypothesis

In order to estimate risks of clofentezine exposur es in aquatic and terres trial environments, all exposure modeling and resulting risk conclusion s were made based on the maximum application rate, which is 0.26 lb a.i./A for all uses. As only one application may be made per season, no more than one ‘season’ of crop pr oduction in a year is expected, and clofentezine is not highly persistent in the environment, there is no need to model repeated applic ation. Tier II aquatic estimated environmental concentrations (EEC) we re generated with the USEPA Pesticide Root Zone Model (PRZM) and Exposure Analysis Modeling System (EXAMS) models using the EXPRESS shell, ( http://www.epa.gov/ceampubl/swater/express ). The model used to produce terrestrial EECs on food items is T-REX (version 1.5). The model used to derive EECs relevant to terrestrial and wetland plants is TerrPlant (ver. 1.2.2). These models are parameterized using relevant reviewed registrant-submitted environmental fate data. For more information on EPA models, http://www.epa.gov/pesticid es/science/models_db.htm

.

In the preliminary risk assessment, acute and chronic EECs are compared to acute and chronic toxicity endpoint to estimate ri sk to nontarget animals and plants , and to determine if the risk exceed the EPA’s levels of concern. Toxicity le vels are based on the most sensitive toxicity endpoints from surrogate test species. Acut e endpoints are based on mortality, and chronic endpoints are based on adverse effects on growth, re production, or survival. Measures of effect
are obtained from a suite of studies conducted wi th a limited number of surrogate species.

B. Conceptual Model

Spraying of agricultural and ornamental plants will release clofentezine into the terrestrial environment. Most of the clofentezine spray will settle on plants and soil at the target site, while some will drift off site and contaminate nearby terrestrial and aquatic habitats. That which settles on the target site may remain on treated plants, percolate into the soil, or runoff with surface water. Terrestrial animals will be exposed when they feed on contaminated food on treated sites and on sites contaminated by spray dr ift. Spray drift, surface runoff, and movement of soil particles with sorbed re sidues will cause in contaminati on of aquatic habitats, exposing aquatic animals and plants. Little of the applie d residues are likely to vol atilize, and thus longrange atmospheric transport is un likely. In soil, water, and se diment, hydrolysis and photolysis of the parent clofentezine will form 2-chlorobenzoic acid (2-chl orobenzylidine) hydrazide and/or 2-chlorobenzonitrile, thereby exposing terrestria l and aquatic organisms to these degradation products.

Clofentezine is not expected to bioaccumulate in fish in appreciable amounts. A bioconcentration study with the bluegill sunfish measured a low whole-body BCF of 230x and depuration is virtually complete after 3 days (MRID 405522-01). Furthermore, the log K
ow of clofentezine is only moderate (3.1), and the compound degrades rapidly in the environment through photolysis and hydrolysis (half-lives less than 7 days). Therefore, exposure of clofentezine to piscivorous wild life through consumption of fish is expected to be a very minor route of exposure and will not be inve stigated in this risk assessment.37 EPA’s Screening Imbibition Program (SIP) was used to conduct a screen-level assessment for
risk to terrestrial wildlife from drinking of water contaminated with clofentezine. This screening tool determines preliminary risk quotients (RQs) for birds and mammals assuming they are drinking from a water source in which the clofent ezine concentration was equal to the solubility limit. This program found that acute and chr onic RQs from this route of exposure will be no more than 0.001, indicating that drinking water is not s significant route of exposure for terrestrial wildlife. This finding was expected based on the low solubility of clofentezine (34.2 μg/L). Therefore, drinking water was not incl uded as a route of exposure in the conceptual
model for clofentezine.

EPA’s Screening Tool for Inhala tion Risk (STIR, version 1.0) was used to screen for the potential of risk to birds and mammals from inhalation of clofen tezine from foliar application. STIR calculates risk based on a theoretical upper bound estimate of inhalation exposure based on the maximum application rate, vapor pressure, and molecular weight. Based on the results of the STIR model, inhalation is not a si gnificant route of exposure for te rrestrial wildlife. This finding was expected based on the low vapor pressure of clofentezine (9.75 x 10 -10 mmHg). Therefore, inhalation was not included as a route of expos ure in the conceptual model for clofentezine.

C. Risk Hypothesis

The Agency will employ the following risk hypothe sis when assessing ecologi cal risks of the use
of clofentezine:

Clofentezine, when used in accordance with current labels, may resu lt in contamination of ecosystems and adverse effects upon the survival, growth, a nd reproduction of nontarget terrestrial and aquatic organisms, including organisms that are federally-listed as threatened and endangered species.

D. Conceptual Diagram

The potential exposure pathways and effects of clofentezine are depicted for aquatic environments in Figure 3 and for terre strial environments in Figure 4.38 Figure 3. Conceptual model depicting stressors, exposure pathways, and potential effects to aquatic animals and plants from the use of clofentezine.39 Figure 4. Conceptual model depicting stressors, exposure pathways, and potential effects to terrestrial animals and plants fr om the use of clofentezine.



### IV. Exposure Analysis

A. Use Characterization

Registered uses of clofentezine are described in detailed in section I.C of this document.
Clofentezine is used for mite control in orchar ds of various non-citrus tree crops fruit trees (including apples, apricots, cher ries, nectarines, peaches, pear s, and persimmons), nut trees (almonds and walnuts), and grapes. Clofentezine is also used on Christmas tree farms. All of
these outdoor uses are evaluated in this ecological risk assessment. Indoor use of clofentezine on ornamental plants in greenhouses is not expected to release si gnificant contaminants into the
environment and is therefore not considered in this assessment. Information on the usage of
clofentezine in the United Stat es is provided in Appendix A.

B. Aquatic Fate and Exposure Characterization

1. Fate Characterization

Abiotic hydrolysis and direct photolysis in water (clear shallow water) and microbial-mediated degradation are major routes of transformation for clofentezine in the environment. Abiotic40 hydrolysis is pH and temperature dependent. At 25°C, the hydrolytic half-lives of clofentezine are 10.4 days (pH 5), 1.4 days (pH 7) and 0.18 days (pH 9). The direct phot olysis half-life is 8.8 days. Although clofentezine under laboratory conditi ons appears to be more persistent in aerobic soil (t 1/2 = 4 weeks in clay, 6 weeks in loamy sand a nd 8 weeks in clay loam), abiotic hydrolysis and/or direct photolysis are likely to control the degrad ation of clofentezine in the environment. However, extensive mineralization (i.e., CO 2 formation, up to 56% in ae robic soil after one year)
was found in the aerobic soil metabolism studies. Thus, mineralization can also be included as a
route of transformation in th e environment. The proportion of radioactivity becoming irreversibly bound to soil increases with time to between approximately 30% and 50% of applied radioactivity depending on soil ty pe. Levels of 'bound' radio activity further increase after
establishment of anaerobic conditions.

The USEPA EPI (Estimation Programs Interface) Su ite program was used to estimate the Koc for clofentezine and its potential mobility in soils. Based on the predicted value of 516.1 L/kg, clofentezine is not expected to be very mobile in the environment. The low aqueous solubility of clofentezine (34.2 μg/L) also limits its transpor t in ground and surface water. Clofentezine has low potential to volatilize from soil or water.

Whole system aerobic and anaerobic aquatic half -lives were calculated for water/sediment samples collected from two rivers in the Unite d Kingdom. Whole-system half-life values are 23.0 and 28.9 days for the Taunton River system and Weweantic River system, respectively. PMRA-calculated, whole-system half-life valu es are 44.9 and 33.2 days for the Taunton River system and Weweantic Rive r system, respectively.

2. Model Input Parameters

The physical/chemical and environmental fate pr operties for clofentezine used as the input parameters in modeling to estimate potentia l aquatic environmental concentrations are summarized in Table 16, which also take into acc ount the required 100-foot buffers, as stated on product labels.41 Table 16. Input Parameters Used in PR ZM/EXAMS Modeling to Estimate Aquatic
Concentrations of Clofentezine

Input Parameter (Symbol; Unit) Value for Clofentezine

Molecular Weight 303.15

Vapor Pressure (torr) 9.75 x 10 -10 , mm Hg
1.31 x 10 -7 , Pa

Henry’s constant (25 o C) 1.14 x 10 -8 atm-m 3 mole -1

Solubility in Water (mg/L at 25 o C) 0.0342

Hydrolysis Half-life (t 1/2 at pH 7) 1.4 days

Aquatic Photolysis Half-life (days; t 1/2 at pH 7) 8.8 days

Aerobic Soil Metabolism [upper 90 th percentile confidence
bound on the mean half-life value (t 1/2 ; 28, 42 and 56 days)] 57.2 days

Aerobic Aquatic Metabolism Half-life (t 1/2 ; days) [Entire water/sediment system; upper 90 th percentile confidence bound on the mean half-life value (t 1/2 ; 28.9, 23.0,18.2,18.9)] 25.8 days

Anaerobic Aquatic Metabolism Half-life (t 1/2 ; days) [Entire water/sediment system; upper 90 th percentile confidence bound on the mean half-life value (t 1/2 ; 44.9 and 33.2)] 57.1 days

Average Organic Carbon-Water Partitioning Coefficient (K
oc ; mL/g) (EPI Suite Program Version 4.10) 516.1

PRZM Scenarios and Application Dates North Carolina Apple: Oct 11 New York Grape: Oct 1 Calif. Almond: Sept 30 Oregon Christmas Trees: Dec 17

Spray Drift Fraction (100 foot buffer) (From GENEEC2) 7.37

3. Estimated Environmental Concentrations

Potential aquatic exposures were estimated using the Tier II models Pesticide Root Zone Model (PRZM v3.12.2, May 12, 2005) and Exposure An alysis Modeling System (EXAMS v2.98.04.06, April 25, 2005) coupled with th e input shell pe5.pl (Nov. 16, 2006). PRZM simulates fate and transport of pesticides on the agricultural field and EXAMS simulates the fate and resulting daily concentrations of pesticides that reach an ad jacent water body through runoff, erosion, and spray drift. Simulations are based on crop-specific sc enarios developed to represent environmental conditions at sites at high runo ff-vulnerability for pesticide tran sport to surface waters from a particular crop. Exposure is estimated using a standard pond scenario based on a10-ha field bordering a 1-ha water body, 2-m deep (20,000 m 3 ) with no outlet. Using appropriate scenarios linked with local meteorological data, the model is run for 30 years with the reported EECs representing the values that are expected once ev ery ten years, based on the thirty years of daily values generated during the simulation. Additi onal information about model assumptions and uncertainties, input guidance, and scenario meta data are available at the EPA’s water modeling website, http://www.epa.gov/oppefed1/models/water/

.42 Tier II aquatic EECs for register ed outdoor uses on crops are liste d in Table 17. The use rate and application method is similar for all uses, but diff erent scenarios were used for fruit trees, grapes, nut trees, and Christmas trees to best represent these use sites. The complete output from the PRZM/EXAMS runs conducted is provided in Appendix C.

Table 17. Tier II Surface Water Estimated Environmental Concentrations (EECs) for Registered
Uses of Clofentezine

Crop/Use Site Model Scenario Peak

μ g/L (ppb) 21-day μ g/L (ppb) 60-day

μ g/L (ppb)

Fruit Trees (1 ground application @ 0.26 lb a.i./A) North Carolina Apples (NC1App-P) 3.34 0.406 0.145

Grapes (1 ground application @ 0.26 lb a.i./A) New York Grapes (NY2Gra-P) 1.02 0.170 0.0742

Almonds and Walnuts (1 ground application @ 0.26 lb a.i./A) California Walnuts (CA1Wal-P) 0.454 0.0705 0.0265

Christmas Trees (1 ground application @ 0.26 lb a.i./A) Oregon Christmas Trees
OR1Xma-P 0.964 0.123 0.0430

4. Monitoring Data

There were no reported detections of clofentezine residues in gr ound water at the time that the Pesticides in Ground Water Data Base was pub lished, in 1992 (USEPA, 1992). This may be because very few ground-water samples have been analyzed for clofentezine residues in the United States and because it has limited usage ar eas and crops. Clofentezine were not included in the suite of analyses conducted in the USEP A's National Survey of Pesticides in Drinking Water Wells (USEPA, 1990). Clofentezine also was not included in the USGS NAQWA program. No surface water monitoring was located.

The California Department of Pesticide Regulation (CDPR) surface water database ( http://www.cdpr.ca.gov/docs/ emon/surfwtr/surfcont.htm ), USGS NAWQA surface and ground water database ( http://infotrek.er.usgs.gov/apex/f?p=136:1:0::NO::: ), Pesticide Data Program ( http://www.ams.usda.gov/AMSv1.0/ams.fetchTemplateData.do?template=TemplateG&navID= &rightNav1=&topNav=&leftNav=ScienceandLa boratories&page=PDPDownloadData/Reports& resultType=&acct=pestcddataprg ), and the USGS/EPA Reservoir Data Program were evaluated for available monitoring data. No detects were se en for clofentezine in any of these databases; however, it is important to note that these sources di d not appear to be looking for clofentezine in water bodies. As a result, no detects does not nece ssarily mean that clofen tezine is not found in surface and ground water sources.

C. Terrestrial Exposure

Terrestrial exposure estimates for avian and mamma lian risk assessments were derived using the T-REX model (version 1.5, 3/22/2012). All terr estrial EECs for clofentezine are based on a43 single foliar application at the maximum rate of 0.26 lb a.i./A. Input parameters used in this modeling are given in Table 18. The default value of 35 days was used as the foliar half-life
because the distribution of chemical -specific half-lives for clofent ezine is uncertain. As only one application was modeled, the peak EEC which ar e used to calculate acute and chronic risk quotients occurs immediately appl ication. Therefore, the selecti on of the foliar half-life has no effect on the calculated terrestrial EECs or RQs. Because clofentezine degrades fairly rapidly through photolysis, and the foliar half-life may be considerably less than the default value of 35 days, the persistence of folia r residues may be less than predicted by the T-REX model. Implications of this potentially more rapid dissi pation from terrestrial food will be explored in the Risk Description and Charact erization section (Section VI).

Table 18. Input Parameters for T-REX M odeling for All Uses of Clofentezine

Input Parameters Value Source Single Application Rate (lb a.i./A) All Uses: 0.26 EPA Reg. No.

Foliar Half-life 35 days Default value 1
Number of Applications (Interval between Applications, days) All Uses: 1 EPA Reg. No. 66222-47, 66222- 53, 66222-65

Avian Oral LD 50 7500 mg/kg-bw (bobwhite) MRID 00105913
Avian Dietary LC 50 19,900 mg/kg-bw (bobwhite) MRID 00159117

Avian NOAEC 30 mg/kg-diet (bobwhite) MRID 42776101

Mammal LD 50 3200 mg/kg-bw (rat) MRID 00159071

Mammal NOAEC 50 mg/kg-diet (rat) MRID 44399146

1 The foliar half-life did not influence the prediction of th e terrestrial EECs for clofentezine because only one application of clofentezine is allowed per season, and th us the peak concentration occurs immediately after this single application before any dissipation occurs.

Terrestrial EECs for dietary-base d calculations are given in Ta ble 19, and terrestrial EECs for dose-based calculations are give n in Table 20. Complete output from the T-Rex Model is provided in Appendix D.

Table 19. Dietary-Based Cl ofentezine EEC Values
Dietary Item Dietary-Based EEC (mg/kg)
Short Grass 62.40
Tall Grass 28.60
Broadleaf Plants 35.10 Fruits, Pods, and Seeds 3.90 Arthropods 24.4444 Table 20. Avian and Mammalian Dose-Based Clofentezine Upper Bound EEC Values

Application Rate (crop) Size Class (g) Avian Dose-Based EECs (mg/kg-bw)
Dietary Item

Short Grass Tall Grass Broadleaf
Plants Fruits &
Pods Arthropods Seeds

Avian One application @ 0.26 lb a.i./A (all uses) 20 71.07 32.57 39.98 4.44 27.83 0.99

100 40.53 18.57 22.80 2.53 15.87 0.56

1000 18.14 8.32 10.21 1.13 7.11 0.25

Mammalian One application @ 0.26 lb a.i./A (all uses) 15 59.46 27.27 33.47 3.72 23.30 0.83

35 41.12 18.85 23.13 2.57 16.10 0.57

1000 9.53 4.37 5.36 0.60 3.73 0.13



### V. Risk Estimates for Non-Target Organisms

A. Aquatic Organisms

1. Aquatic Animals

Table 21 provides RQs for risk to fish from acute and chronic exposures associated with uses of clofentezine. Because of the very low solubility of clofentezine , all of the acute and chronic toxicity endpoints are nondefinitive, in that th e tests were only able to show that the LC 50 value is greater than the highest test concentration, or in the case of te sts with the TEP, are greater than the solubility limit of clofentezine (34.2 μg/L). Because the toxicity va lues are expressed as “greater than” inequalities, the RQs calcula ted from them are expressed as “less than” inequalities, indicating the upper bou nd of the RQ. For fish, acute risk quotients were shown to
be less than EPA’s LOC for risk to nonenda ngered species (0.5) and the LOC for potential adverse effects to endangered sp ecies (0.05) for all us e sites except fruit trees. For use on fruit trees, the RQ for fish was only shown to be less than 0.10, and therefore wa s not demonstrated to be less than the LOC for endangered species. Ho wever, since no treatment-related mortality or
adverse effects observed in the acut e toxicity test with the TGAI at close to the solubility limit (MRID 40568201), or with the TEP at nominal con centrations exceeding the solubility limit (MRIDs 40912101 and 00159120), the EPA concludes th at acute exposure from all uses of clofentezine, including on fruit trees, will not resu lt in adverse effects to listed species of fish (see Section VI.A.1 for more discus sion). For risk from chronic exposure, RQs for all use sites were less than 1, and therefore the RQ did not ex ceed the LOC for chronic risk (1) for all uses.

For fish, toxicity testing with the rainbow trout found no mortality or adverse effects at exposure at or near the solubility limit (MRID 00159120). Th erefore, the EPA concl udes that clofentezine
will not cause adverse acute effects at concentrations that would occur in natural waters. Therefore, a “no effect” conclusion is made for fish for all uses, including use on fruit trees.45 Since acute and chronic toxicity tests with saltwater fish are no t available, the conclusions for
freshwater fish are assumed for saltwater fish as well, although these conc lusions are uncertain.

In summary, the EPA concludes th at all registered uses of clof entezine pose minimal risk to freshwater and saltwater fish, a nd are not expected to harm thr eatened or endangered species of
fish.

Table 21. Acute and Chronic Risk Quotients for Fish Crop (Application

method) Exposure Type Habitat Type Toxicity (μg a.i./L) EEC (μg a.i./L) RQ

Fruit Trees (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 3.34 <0.10

Saltwater N/A 3.34 N/A 1

Chronic Freshwater >34.2 0.145 <0.01

Saltwater N/A 0.145 N/A 1

Grapes (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 1.02 <0.03

Saltwater N/A 1.02 N/A 1

Chronic Freshwater >34.2 0.0742 <0.01

Saltwater N/A 0.0742 N/A 1

Almonds and
Walnuts (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 0.454 <0.01

Saltwater N/A 0.454 N/A 1

Chronic Freshwater >34.2 0.0265 <0.01

Saltwater N/A 0.0265 N/A 1

Christmas Trees (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 0.964 <0.03

Saltwater N/A 0.964 N/A 1

Chronic Freshwater >34.2 0.0430 <0.01

Saltwater N/A 0.0430 N/A 1

1 No toxicity data are available for saltwater fish; however, based on the very low toxicity observed in freshwater fish, the RQ for saltwater fish is also expected to be well below 0.01.

Table 22 provides RQs for risk to aquatic i nvertebrates from acute and chronic exposures
associated with uses of clofentezine. Because of the very low solubility of clofentezine, all of the acute toxicity endpoints for aquatic inverteb rates are nondefinitive. As for fish, the acute toxicity tests were only ab le to show that the EC 50 value is greater th an the highest test concentration or the solubility limit of clofentezi ne (34.2 μg/L). Because the toxicity values are expressed as “greater than” inequalities, the RQs calculated from them are again expressed as “less than” inequalities. Acut e toxicity tests using the TGAI were supplemental and were conducted at levels less than the solubility limit. The acceptable acute toxicity test using the formulated product (MRID 40568202) was therefor e used for RQ calculations. Since the
nominal test concentrations in this test were much greater than the solubility limit of clofentezine, the concentration of dissolved clofentezine is assumed to have been close to the solubility limit of 34.2 μg a.i./L. As for fish, acute risk quotients were found to be less than EPA’s LOC for risk to nonendangered species (0.5 ) and the LOC for potential adverse effects to endangered species (0.05) for all use sites except fruit trees. For use on fruit trees, the RQ was only shown to be less than 0.10 and therefore do es not preclude possible adverse effects to46 endangered species. For risk from chronic exposu re, RQs for all use sites were less than 1, and therefore the RQ did not exceed the LOC for chronic risk (1) for any use.

In the acceptable acute toxicity study with daphnid (MRID 40568202), no more than 3 out of 30 (10%) of daphnids were immobilized at any test concentration, which equals the number that were immobilized in the negative control. At the highest test c oncentration (nominal concentration of 100 mg a.i./L), there were 2 daphnids immobilize d, less than in the control.
Because the number of immobilized daphnids in the treatments did not exceed the number in the control, they are assumed to be incidental and not treatment related. Ot her than immobilization,
no sublethal effects were observed at any test concentration. Becau se exposure to daphnids at the solubility limit did not result in any significant adverse effects (i.e., effects greater than in the control), the EPA concludes that all uses of cl ofentezine, including use on fruit trees, will cause
no acute toxic effects to threatened and enda ngered species of aquatic invertebrates.

Chronic studies with clofentezi ne found that it does negative ly affect the reproduction of
freshwater and saltwater invert ebrates, but only at concentr ations above the chronic EECs predicted for registered uses. Because the chronic NOAEC for both fres hwater and saltwater crustaceans are greater than the chronic EECs, all of the chronic RQs are less than 1.0, and
therefore does not exceed the EPA’s chronic LOC.

In summary, the EPA concludes th at all registered uses of clof entezine pose minimal risk to
freshwater and saltwater inverteb rates, and are not expected to cause any adverse effects to threatened or endangered sp ecies of invertebrates.

Table 22. Acute and Chronic Risk Quo tients for Aquatic Invertebrates

Crop (Application

method) Exposure Type Habitat Type Toxicity (μg a.i./L) EEC (μg a.i./L) RQ

Fruit Trees (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 3.34 <0.10

Saltwater N/A 3.34 N/A 1

Chronic Freshwater 44 0.406 0.01 2

Saltwater 1.7 0.406 0.24
Grapes (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 1.02 <0.03

Saltwater N/A 1.02 N/A 1

Chronic Freshwater 44 0.170 <0.01 2

Saltwater 1.7 0.170 0.10

Almonds and
Walnuts (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 0.454 <0.01

Saltwater N/A 0.454 N/A 1

Chronic Freshwater 44 0.0705 <0.01 2

Saltwater 1.7 0.0705 0.04

Christmas Trees (1 ground application @ 0.26 lb a.i./A) Acute Freshwater >34.2 0.964 <0.03

Saltwater N/A 0.964 N/A 1

Chronic Freshwater 44 0.123 <0.01 2

Saltwater 1.7 0.123 0.0747 1 No toxicity data are available for saltwater invertebrate s; however, based on the very low toxicity observed in freshwater invertebrate, the RQ for saltwater invert ebrate is also expected to be well below 0.01. 2 The RQ is uncertain because it is base d on the LOAEL rather than the NOAEL.

2. Aquatic Plants

An algal toxicity test with the TEP (MRI D 47200501) found no observable adverse effects to green algae at nominal concentrations up to 100 mg product/L. The test concentrations of dissolved clofentezine in this study are unknown b ecause the samples used for chemical analysis were not filtered before analysis. However, the dissolved concentrations in the test solutions are expected to be close to the so lubility limit, and thus the study demonstrated that clofentezine does not adversely affect the growth of green al gae up to the aqueous sol ubility limit of 34.2 μg a.i./L. Based on this, the RQs for both endange red and nonendangered species of nonvascular aquatic plants are well below the LOC of 1 for all uses of clofentezine (Table 23).

Lack of data on the toxicity of clofentezine to vascular aqua tic plants prevents quantitative assessment of risk to vascular aquatic plants. Va scular plants would need to be over 9.7 times more sensitive than the tested nonvascular aquatic plant (green algae) for the RQ to exceed the
LOC. Since clofentezine does not have a known mech anism of action that is relevant to toxicity to plants, exhibited low phytotoxicity in a study of terrestrial vascular plants, has no reported problems with plant safety, and is expected to occur in natu ral water at only very low concentrations, use of clofentezine is not expected to pose signif icant risk to vascular aquatic plants.

Table 23. Risk Quotients for Aquatic Plants

Crop (Application method) Plant Type Toxicity (μg a.i./L) EEC (μg a.i./L) RQ

NonEndangered Endangered

Fruit Trees (1 ground application @ 0.26 lb a.i./A) Vascular N/A 3.34 N/A N/A

Non-vascular IC 50 : >34.2
NOAEC: >34.2 3.34 <0.10 <0.10

Grapes (1 ground application @ 0.26 lb a.i./A) Vascular N/A 1.02 N/A N/A

Non-vascular IC 50 : >34.2
NOAEC: >34.2 1.02 <0.03 <0.03

Almonds and Walnuts (1 ground application @ 0.26 lb a.i./A) Vascular N/A 0.454 N/A N/A

Non-vascular IC 50 : >34.2
NOAEC: >34.2 0.454 <0.01 <0.01

Christmas Trees (1 ground application @ 0.26 lb a.i./A) Vascular N/A 0.964 N/A N/A

Non-vascular IC 50 : >34.2
NOAEC: >34.2 0.964 <0.03 <0.0348 B. Terrestrial Organisms

1. Terrestrial Wildlife

Table 24 provides acute and chronic risk quotie nts (RQs) for birds based on dietary toxicity studies, and Table 25 provides ad ditional acute RQs based on single- dose oral toxicity studies.
Since all uses of clofentezine ar e restricted to one application with a maximum application rate of 0.26 lb a.i./A, the RQs presented in these tables are applicable for all registered outdoor uses of clofentezine (indoor greenhouse uses are not expect ed to pose risk to nontarget wildlife). As birds are used as surrogate species for assessing risk to reptiles and terrestrial-phase amphibians, inferences based on these RQs are applied to th ose groups of organisms as well. The very low acute toxicity of clofentezine re sulted in all of the acute RQs be ing very low. All acute RQs are well below EPA’s levels of concern (LOCs) for ge neral risk to birds (0.5 ) and risk of adverse effects to threatened and endangered species of birds (0.1). Thus, EPA conc ludes that all of the registered uses of clofentezine pose minimal acute risk to birds, reptiles, and terrestrial-phase amphibians.

Toxicity data show that sublet hal effects caused by chronic expos ure to clofentezine occur at much lower exposure levels than those which may cause mortality. Thus, chronic RQs are higher than acute RQs, although they are somewhat limited by the relatively low maximum application rate and the restriction of use to one application per growing season. Dietary-based chronic RQs are based on the observation of redu ced embryo viability in the bobwhite quail at 90 mg ai/kg/diet, yielding a chr onic NOAEL of 30 mg ai/kg-diet (MRID 42776101). Chronic RQs
exceed the EPA’s level of concern for chronic eff ects to birds (1.0) for birds that feed on short grass and broadleaf plants (Table 24). This screening-level assessment indicates that all registered outdoor uses of clofentezine pose a ch ronic risk to birds, re ptiles, and terrestrialphases of amphibians, including threatened and endangered species of birds, reptiles, and terrestrial-phases of amphibians.

Table 24. Acute and Chronic Dietary-Based RQs for Birds

Application Rate (crop) Exposure Avian Dose-Based EECs (mg/kg-bw) Dietary Item

Short Grass Tall Grass Broadleaf
Plants Fruits, Pods, &

Seeds Arthropods

One application @ 0.26 lb a.i./A (all uses) Acute <0.01 <0.01 <0.01 <0.0 1 <0.01

Chronic 2.08 0.95 1.17 0.13 0.8149 Table 25. Acute Dose-Based RQs for Birds

Application Rate (crop) Size Class (g) Avian Dose-Based EECs (mg/kg-bw)
Dietary Item

Short Grass Tall Grass Broadleaf
Plants Fruits &
Pods Seeds Arthropods

One application @ 0.26 lb a.i./A (all uses) 20 0.01 0.01 0.01 <0.01 <0.01 0.01

100 0.01 <0.01 <0.01 <0.01 <0.01 <0.01

1000 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Table 26 provides acute and chr onic risk quotients (RQs) for mamma ls based on dietary toxicity studies, and50 Table 27 provides additional acute RQs based on single-dose oral toxic ity studies. The RQs presented in these tables are applicable for all re gistered outdoor uses of clofentezine. The very low acute toxicity of clofentezine resulted in al l of the acute RQs being very low. All acute RQs are well below EPA’s levels of concern (LOCs) for risk to mammals (0.5) and risk of adverse effects to threatened and endangered species of mammals (0.1). Thus, EPA concludes that all of the registered uses of clofentezine pose minimal acute risk to mammals.

However, toxicity data show that sublethal e ffects to mammals caused by chronic exposure to
clofentezine occur at lower e xposure levels than those which may cause mortality, making the chronic RQs higher than the acute RQs. Dietar y-based chronic RQs are based on the observation of parental toxicity in the la boratory rat at 500 mg a.i./kg-di et, yielding a chronic NOAEC of 50 mg a.i./kg-diet (MRID 44399146). The chronic di etary-based RQ exceeds the EPA’s level of
concern for chronic effects to birds (1.0) for mammals that f eed on short grass (Table 26). Chronic dose-based RQs also exceed the chronic LOC for mammals of all weight classes which feed on grass, broadleaf plants, or arthropods (51 Table 27). The Agency therefore concludes that a ll registered outdoor uses of clofentezine pose a chronic risk to mammals, including th reatened and endangered mammals.

Table 26. Acute and Chronic Di etary-Based RQs for Mammals

Application Rate (crop) Exposure Mammalian Dietary-Based EECs (mg/kg-bw) Dietary Item

Short Grass Tall Grass Broadleaf
Plants Fruits, Pods, &

Seeds Arthropods

One application @ 0.26 lb a.i./A (all uses) Acute <0.01 <0.01 <0.01 <0.0 1 <0.01

Chronic 1.25 0.57 0.70 0.08 0.4952 Table 27. Acute and Chronic Dose-Based RQs for Mammals

Application Rate (crop) Size Class (g) Mammalian Dose-Based EECs (mg/kg-bw)
Dietary Item

Short Grass Tall Grass Broadleaf
Plants Fruits &
Pods Seeds Arthropods

Acute One application @ 0.26 lb a.i./A (all uses) 20 0.01 <0.01 <0.01 <0.01 <0.01 0.01

100 0.01 <0.01 <0.01 <0.01 <0.01 <0.01

1000 <0.01 <0.01 <0.01 <0.01 <0.01 <0.01

Chronic One application @ 0.26 lb a.i./A (all uses) 15 10.83 4.96 6.09 0.68 0.15 4.24

35 9.25 4.25 5.20 0.58 0.13 3.62

1000 4.96 2.27 2.79 0.31 0.07 1.94

2. Terrestrial Plants

In a vegetative vigor study, four dicotyledonous plants and two monocot yledonous plants were exposed to Apollo 50 SC (49.8% a.i.) at a ra te of 0.26 lb a.i./A (MRID 47192103). This limit test measured inhibition of plant wet weight and phytotoxic effects. Compared to the control, the plants exposed to 0.26 lb a.i./A did not show a ny significant reduction in biomass, as measured by plant wet weight, and did not sh ow any signs of phytotoxicity. The application rate used in this study was equal to the maximum application rate for all registered crops. The EEC for nontarget terrestrial plants living outside the treatment site would be less than this application
rate. As the EEC has been demons trated to be less than the IC 25 and NOAEL, the RQs for both endangered terrestrial plants (EEC/NOAEL) and nonendangered terrestri al plants (EEC/IC 25 ) would be less than 1.0. The risk to emerged nont arget plants, including endangered species, is
thus less than the EPA’s level of concern.

No data are available on the effects of clof entezine on the germination and emergence of nontarget plants. Therefore, risk from inhibition of the germin ation and emergence of seeds is not known. However, considering that the vegeta tive vigor test found that clofentezine does not have any phytotoxicity activity at the maximum use rate, and cl ofentezine is recommended for use on a wide variety of woody and herbaceous plants in greenhouse use without any reported phytotoxicity, the EPA assumes that use of clofent ezine will not pose any risk significant risk to nontarget plants.

3. Bees and Other Nontarget Terrestrial Arthropods

Multiple lines of evidence indicate that use of clof entezine pose little risk to bees. An acute
contact test with adult h oney bees determined the LD 50 to be >1500 mg a.i./L. Based on recommended dilution rates provided on the produc t labels, concentrations of clofentezine in tank mixtures would not be grea ter than approximately 600 mg a.i./L. The 48-hr mortality measured for bees exposed at a spray concentr ation of 1500 mg a.i./L was 3.3%, which was less than the mortality observed in the vehicle cont rol. Thus this study i ndicates that direct application of clofentezine produc ts to adult bees would cause li ttle or no mortality. An acute53 oral toxicity honeybee study (MRI D 00159121) found that the acute oral toxicity of clofentezine was >20 μg a.i./bee. While the EPA does not have a bee toxicity classification scheme for acute oral exposure, if the scheme for acute contact toxicity for adult honey bees were applied, clofentezine would be classified as practica lly nontoxic to bees. Yoshida and Fuchs (1989) found that acute contact of larval honey bees (5 th instar) caused elevated mortality with exposures of 50 μg a.i./bee or greater, and caused increased occurrence of abnormal development at concentrations of 25 μg a.i./b ee and greater. The LOAE L of 25 μg a.i./bee was associated with abnormal development of 42.3% of the pupa. By assuming all of the abnormal pupa would die, this LOAEL may be used as a conservative estimate of the LD 50 for exposed bee larvae. Again, if this conservative estimate of the LD 50 for bee larvae were compared to the
scheme based on the acute contact LD 50 for adult honey bees, clofentezi ne would be classified as practically nontoxic to bees.

Yoshida and Fuchs (1989) derived an NOAEL for de velopmental toxicity resulting from topical exposure of clofentezine of 5 μg a.i./bee. By converting this NOAEL to a dose expressed as the amount per body weight, this NOAEL can be compar ed directly to the terrestrial EEC for arthropods to assess the potential for risk to bees. Assuming a honey bee weight of 0.128 g (USEPA, 2012), the NOAEL is equivalent to a do se of 39 mg a.i./kg-bw. The maximum EEC for arthropods is 24.4 mg/kg (Table 19). Theref ore, this evaluation i ndicates that topical exposure of clofentezine to the honey bee will be below levels that would cause toxic effects. This conclusion is uncertain, however, because the published study lacked replication, requiring effects levels to be estimated through visu al inspection, and did not evaluate growth measurements such as size or weight.

In a pollen feeding study (Yoshida and Fuchs, 1989), instances of abnormal development were observed when bee larvae were fed pollen with a clofentezine concentration of 1000 mg a.i./kgpollen, but no instance of abnormal development was observed with exposur e concentrations of 100 mg a.i./kg-pollen or less. The same study found th at the percentage of L1 and L2 larvae that sealed their cells appeared to decr ease with clofentezine concentra tions in pollen of 10 mg a.i./kg and greater. Compared to the control, the pe rcentage of sealed cells decreased 6.9% and 9.1% when exposed to 10 and 100 mg a.i./kg. No d ecrease in sealed cells was evident in larvae exposed at the L3 through L5 stages with exposur e concentrations up to 1 000 mg a.i./kg. This is
consistent with the known mode of action of clofen tezine to mites, the target arthropods, which is toxicity to eggs and early developmental stages. Unfortunately this study was conducted without replication, and thus the statistical significance of observed trends could not be
determined.

To characterize potential risk to the honey bee, EFED compar ed the effect concentrations observed in the pollen feeding study of Yoshida and Fuchs (1989) with terrestrial EECs for plants treated directly with the maximum appli cation rate (Table 19). The terrestrial EECs for plants range from 3.9 mg/kg (for fruits and pods) to 62.4 mg/kg (f or short grass). Thus, plant
EECs are below the NOAEL for observed abnormal development of bee larvae (100 mg/kg), but were within the range in which a small percen tage of observed adverse effects in bee larvae (<10% decrease of sealed cells). This suggests th at if honey bees were to forage the flowers of plants directly treated with cl ofentezine soon after application, and bring contaminated pollen back to the hive for feeding to larval bees, ther e is potential for risk to bees of the earliest54 development stages. While not ev aluated in this study, exposure in the hive could possibly also cause toxicity to the eggs of bees, as was obser ved in a study with the la dybird beetle (Olszak 1999). However, as clofentezine may be appl ied only once per growing season, and residues on foliage are not expected to be highly persistent (estimated half-life is 15.7 days), the overall effect on reproduction of the hive is e xpected to be minor and transient.

Being an acaricide, some toxic ity to nontarget arthropods is expe cted. Studies with beneficial
insects have found clofentezine to have very little toxicity to adult insects at environmentally
relevant concentrations. Studies indicating that clofentezine is practically nontoxic to adult bees have already been discussed (see above). A nonguideline study submitted by the registrant (MRID 47192122) found no adverse eff ects to a ladybird beetle ( Coccinella septempunctata ) when they were exposed to clofentezine spray at application rates of 0.089 and 0.18 lb a.i./A. Samsoe-Peterson (1993) observed no mo rtality in adult rove beetles ( Aleochara bilineata ) when sprayed with a solution of clofentezine at a co ncentration and spray ra te equivalent to the maximum application rate. However, studies have found that environmentally-relevant exposures to clofentezine can cause adverse effects on survival and development of the early life-stages of insects, including honey bees (Yoshida and Fuchs, 1989), coccinellid beetles (Olszak, 1999), and rove beetles (Samsoe-Peterson, 1993). Because of this, these data indicate that use of clofentezine may pose a risk to non listed and threatened and endangered arthropods that forage in treated orchards and tree farms. Overall, though, the toxicity and risk of clofentezine to nontarget arthropod s appear to be less than that of most insecticides (SamsoePeterson, 1993; Olszak, 1999).

In conclusion, toxicity data on the effects of clofentezine to adult and immature bees do not warrant placement of any label statement to clofen tezine products for the protection of bees. Use of clofentezine is not expect ed to harm adult nontarget arth ropods which may be exposed in treated sites during or after appl ication. However, there is a potential for risk to nontarget arthropods from potential reproduction impairment and toxicity to early life-stages. Direct
adverse effects to threatened and enda ngered arthropods are therefore possible.



### VI. Risk Description and Characterization

The results of this screening-level risk assessmen t indicate that the foliar uses of clofentezine have the potential for direct adve rse effects to listed or non-list ed birds (and, thus, reptiles and terrestrial-phase amphibians), mammals, and te rrestrial arthropods. Therefore, the risk hypothesis from the Problem Formulation is suppor ted based on expected direct effects to these species. Because direct adverse e ffects to these taxa considered in this assessment are expected, indirect effects to listed species are also expected through potentia l alterations to food source.

A. Risk to Aquatic Organisms

1. Aquatic Animals

Aquatic exposure to clofentezine is limited by seve ral factors: the relatively low application rate, the low mobility in water, the low solubility in water, and the relatively rapid degradation of the55 parent by hydrolysis and photolysis. Clofentezine has also been f ound to not be toxic to fish and aquatic invertebrates at concentrations up to the so lubility limit. This was sufficient to show that the acute RQ was less than the endangered spec ies LOC of 0.05 for all uses except the use on fruit trees, for which the acute RQ was only shown to be less than 0.10. Aquatic TGAI toxicity tests with fish and daphnids were conducted up to concentrations near saturation of clofentezine. In the TEP studies, reliable measurements of diss olved active ingredient in the test solutions are not available, but since nominal test concentrations made with the suspended concentrate product far exceeded the solubility limit of clofentezine, the dissolved concentration of clofentezine in
these test solutions are also assumed to have been close to the solubility limit. Both the TGAI and TEP studies found clofentezine caused no signifi cant mortality (i.e., not greater than in the control). Additionally, no sublethal effects were observed for either fish or daphnids at the highest test concentration. Theref ore, despite failing to show that the RQ for use on fruit trees is less than the LOC of 0.05 ( i.e. , failing to demonstrate a 20x ma rgin between the acute EEC and acute toxicity level), EPA believes that the lack of observed adverse effects at the solubility limit of clofentezine is enough evidence to conclude that all uses of cl ofentezine will not result in any adverse effects to fish or aqua tic invertebrates, including endange red species. For chronic risk, all fish and aquatic invertebrate RQs were less than 1 for all uses, indicating chronic risk does
not exceed the EPA’s level of concern.

Clofentezine is applied as products formulat ed as suspension concentrates. Suspension concentrates are composed of small colloidal particles which remain suspended in the formulation and tank mixture when applied. When applied to plants, the solid particles are expected to move little from the use site, with primarily the residues that dissolve in water being transported to natural waters. However, spray drift may deposit onto bodies of water, thereby transporting the entire formulated product, including the colloidal solid particles as well as the dissolved component of clofentezi ne. To evaluate the potential for risk from this route of exposure, the AgDRIFT model (v. 2.01) was used to estimate maximum initial water concentrations in a body of water receiving spray drift deposition. Since a 100-ft buffer zone is required between application areas and natural wa ter, the water body was assumed to be a 100 ft from the edge of the application area. To be cons ervative, fine to very fine spray droplets were assumed, and a small water body was assumed with a width of 10 ft and a water depth of 0.5 ft. The water concentrations estimated by this model were then compared to the toxicity endpoints obtained from the aquatic toxi city tests with the TEP.

Using the maximum product application rate of 8 oz/A (0.5 lb a.i./A), AgDRIFT predicts an
initial water concentrat ion of 8.70 μg product/L if the applic ation was made with a ground boom, or 0.218 μg product/L if it is done an air blast app lication is made. TEP testing with Apollo 50 SC found that product concentrations up to 24 mg /L did not cause mortality to fish (MRID 40912101), and product concentrations up to 100 mg /L did not cause immobility in daphnids above the level observed in the control (MRID 40568202). These test concentrations are over 3 orders of magnitude greater th an the predicted ini tial product concentratio ns in the water body receiving spray drift. Theref ore, spray drift of the product clearly will not yield water concentrations that would appro ach toxic levels, and thus would not result in any adverse acute
effects to fish or a quatic invertebrates.56 Chronic tests with a formulated product of clofentezine found toxi c effects to the reproduction of aquatic organisms, but only at concentrations above those predicted to occur from registered uses of clofentezine. A fish early life stage study with Apollo 50 SC did not find observable sublethal effects at a concentration of 979 μg/L, which is much higher than the pr edicted chronic EECs. All chronic RQs for fish were le ss than 0.01. Clofentezine showed greater toxicity to aquatic invertebrates in life-cycle studies. The most sensitive endpoint in these studies was fecundity (the number offspring produced per female). Reproductive effects were observed at concentrations as low as 44 μg/L in the waterfle a (a saltwater crustacean) and as low as 3.6 μg/L in the mysid (a saltwater crustacean).

The mode of action of clofentezine to the target species, mites, is toxicity to eggs and early life stages. It thus appears that clofentezine ma y exhibit the same mode of action in aquatic arthropods as well. However, a Daphnia magna reproductive toxicity study of Barber and Barrett (1983) suggests an alterna tive explanation of chr onic toxicity to aquatic invertebrates. This study measured the reproductive response of Daphnia magna when exposed to three concentrations of Apollo 50 SC (50% clofentezine) and three concentrations of inert polyvinyl toluene (PVT) latex beads. Apollo 50 SC is a suspension concentrate formulation, meaning that it consists of small particles of solid clofentezine that rema in suspended in the product and applied tank mixture. The te st concentrations of latex b eads had equivalent particle concentrations as did the Apollo 50 SC. The result of the study showed reproduction performance was significantly reduced when e xposed to both the Apollo 50 SC and the PVT bead treatments. The percent re duction in number of offspring produced per female was similar, regardless if the test was conducte d with the clofentezine product or with the latex beads. The study authors thus concluded that th e effect of Apollo 50 SC was not due to any intrinsic toxicity of the formulation, but rather a c onsequence of its particular con centration. They suggest that the ingestion of both the clofentezine particles and the latex beads by the waterflea while filter feeding reduced the organism’s feeding effici ency, which resulted in the organisms having reduced reproductive output.

Regardless of the cause of the chronic toxicity, the lowest NOAEC obtained in the aquatic reproductive test (1.7 μg a.i./L for the mysid) was higher than the highest chronic EEC for aquatic invertebrates (0.49 μg a.i./L for use on fruit trees). The highest chronic RQ was therefore less than the EPA’s chronic LOC (1).

Some uncertainty exists for chronic risk to fr eshwater invertebrates because one study with the waterflea ( Daphnia magna ) failed to identify an NOAEC, fi nding significant reduction in fecundity at the lowest test c oncentration of 44 μg a.i./L (M RID 47192117). This test level is approximately 100 times greater than the maximu m chronic EEC (0.49 μg a.i./L). The percent reduction in number of offspri ngs per female observed at 44 μg a.i./L was relatively small, 8.25%, and thus, even less reduction on offspri ng production is expected at the maximum chronic EEC (0.49 μg a.i./L). Furthermore, two other chronic studies with Daphnia magna which did obtain NOAECs found no significant chroni c effects at test con centrations well above the chronic EEC. A study submitted by the re gistrant (MRID 42523901) obtained an NOAEC of 26.2 μg a.i./L, and a published literature study Ba rber and Barrett (1993) obtained an NOAEC of 60 μg a.i./L. These NOAECs are near to or abov e the solubility limit of clofentezine and well above even the highest predicted peak EEC (4.34 μg a.i./L). Finally, the com parison of results of57 MRID 47192117 with the mysid life-cycle study (M RID 48342701) indicates th at the mysid is the more sensitive species of the two. While a test concentration of 44 μg a.i./L resulted in only an 8.25% reduction in fecundity in the waterflea study, a lower test concentration of 29 μg a.i./L resulted in a 23.7 % reduction in fecundity in the mysid study. Since a lower concentration resulted in greater impairment of reproduction, th e mysid appears to be more sensitive than the waterflea. Thus, the risk conclusions of low chronic risk based on the mysid study should be protective freshwater invertebrates as well.

In conclusion, the lack of a fully acceptable study with a freshwater invertebrate and the nondefinitive results obtained in two of the supplem ental studies increases uncertainty in the risk assessment for freshwater invertebrates, the weight of the evidence indicate that chronic exposure levels will likely remain below levels that could otherwise pose chronic effects such as reproduction impairment.

2. Aquatic Plants

Risk of clofentezine to aquatic plant is uncertain because toxicity data are available for only one species, green algae. An al gal toxicity test with the TEP (MRID 47200501) found no observable adverse effects to green algae at nominal concentrations up to 100 mg product/L. This concentration is far greater than would be expect ed to occur in natural water from deposition of spray drift. Thus, contamination from spray drift of the formulated product would not pose a significant risk to green algae. While this study failed to measure the concentrations of dissolved test material (since the samples were not filtered prior to anal ysis), the amount of suspended
clofentezine added to the test so lutions far exceeded the solubility of clofentezine, and thus the
concentration of clofentezine in the test solutions would likely be close to the solubility limit. Thus, the study demonstrated that clofentezine do es not adversely affect the growth of green algae up to the aqueous solubility limit of 34.2 μg a.i./L. The highest predicted peak EEC was 3.34 μg a.i./L for fruit trees. Thus, there is at least a 10-fold margin of safety between the expected peak exposure levels and the threshold of toxic effects for green algae. As clofentezine is applied only once per year a nd residues in water degrade fair ly rapidly by hydrolysis, water concentrations are expected to decline fairly rapidly from the peak, creating an even greater margin of safety. While some uncertainty exists in the risk assessment because of the lack of testing of species other types of green algae and diatoms, the EPA believes that the available
information is sufficient to conclude that use of clofentezine will not cause significant adverse effects to nonvascular aquatic plants.

Lack of data on the toxicity of clofentezine to vascul ar aquatic plants, and classes of nonvascular aquatic plants other than green al gae, prevents quantitative assessm ent of risk to vascular aquatic plants. However, since clofent ezine does not have a known mechanis m of action that is relevant to toxicity to plants, exhibite d low phytotoxicity in a study of te rrestrial vascular plants, has no reported incidents or issues c oncerning plant safety, there is no reason to suspect that
clofentezine would be toxic to these other classes of aquatic plants. Considering the low solubility of clofentezine, and th e low predicted concentrations in natural waters, registered uses of clofentezine is not expected to pose significant risk to any a quatic plants, and will not likely harm threatened or endangered species of aquatic plants.58 B. Risk to Terrestrial Organisms

1. Nontarget Terrestrial Vertebrates

Acute toxicity studies with both birds and mammals indicate that clofentezi ne has low toxicity to
terrestrial vertebrates. In addition, the relatively low use ra te of clofentezine (0.26 lb a.i./A) limits exposure to terrestrial animals. These tw o factors combine to create very low acute RQs for terrestrial vertebrates, with RQ values below 0.01 for all uses. Additionally, no incidents have been reported that a ttribute wildlife mortality to exposure to clofentezine.

However, chronic exposure to clofentezine is more toxic to terrestrial vertebrates. For birds, adverse effects on reproduction we re observed at dietary concentr ations as low as 90 mg ai/kgdiet, with a NOAEL established at 30 mg ai/L. Maximum EECs of clofen tezine on foliage (short grass and broadleaf plants), assuming exposure immediately after applica tion, are predicted to exceed the chronic NOAEC, making the RQs greate r than the chronic LOC of 1. For mammals, the results were similar except the RQ exceeded chronic LOC only for residues on short grass. When calculated based on the daily expected dose of active ingredie nt per unit body weight, chronic RQs for mammals exceeded 1 for all mo deled weight classes (15, 35, and 100 g) of mammals that feed on foliage (tall grass, shor t grass, or broadleaf plants) or arthropods. While the screening-level risk assessment indi cates potential chronic risk to terrestrial vertebrates, several factors would limit the extent of this risk. First, the terrestrial maximum EECs fall close to the threshold for concluding po tential chronic risk. While a few EECs exceed the NOAEC, none of the EECs exceed the LOAEC. Maximum dietary-based EECs that do exceed the NOAEC do so by no more th an about a factor of 2. Sec ond, clofentezine is not very persistent in the terrestrial envi ronment. The photolysis half-lif e is less than 7 days, and thus residues on foliage and fruit exposed to the sun ar e expected to dissipate fairly quickly. This would mean that the length of exposure to ch ronically toxic residues through consumption of contaminated plants would be fairly short. Finally, only one applicati on of clofentezine is permitted per growing season. This limit reduces the amount and duration of exposure, relative to pesticides with multiple applications.

In the screening-level risk assessment, RQ s are calculated based on the peak EEC ( i.e. , those immediately after application before any degrad ation takes place. This would represent the exposure of an animal feeding in a treated orchar d immediately after treatm ent. The persistence of the residues on the food items being consumed would influence the risk of reproductive and developmental effects occurring in that animal. If the residues quickly drop below potentially toxic levels, then the exposure to the animal in the field would not necessa rily result in the same reproductive or developmental impairment that was observed in chro nic laboratory studies, where the animal is exposed to a set dietary c oncentration for a long duration, such as 21 weeks in the avian reproduction study. While it is pos sible that the shorter-term exposure would produce the same reproductive effect s as the long-term exposure, th is is less certain than for a more persistent chemical, for which the durati on of exposure in the wild would more closely match the duration of exposure in the avian reproduction tests..59 To evaluate the duration that residues on wildlife food items would remain above potentially toxic levels, a half-life for resi due decline on those items must be estimated. The dietary-based risk assessment indicates that animals feeding on plant foliage (short grass or broadleaf plants) may be at risk. Unfortunately data were not ava ilable to measure a half-life for foliar residues. Instead, we used a study which measured the dec line of residues on grapes after treatment with clofentezine (MRID 45080701). A review of this study by the Health Effects Division found it to be scientifically acceptable. While the abso lute concentration of residues on grapes may be quite different than on leaves, the decline of residues is expected to be similar. Thus the half-life of residues in this study is expected to be a reasonable estimate of the foliar half-life.

Table 28 gives residue concentrations measured on grapes between 0 and 21 days after a single application of Apollo at the a pplication rate of 4.0 oz product/ A (0.125 lb a.i./A). From these values, a first-order decline rate (k) was estimated to be 0.0441, and the half-life (T 1/2 ) was estimated to be 15.7 days. This indicates that cl ofentezine residues are moderately persistent on foliage. Assuming the same rate of decline for residues on foliage, the fo liar EECs are expected to decline over time as depicted in Figure 5. For reference, the avian and mammalian NOAEC values are also depicted. For birds, residues on short grass are expected to remain above the NOAEC for approximately 5 days after application. Residues on tall grass and broadleaf foliage are not expected to exceed the NOAEC. For ma mmals, residues on short grass are expected to remain above the NOAEC for approximately 16-17 days, and residues on broadleaf plants are expected to remain above the NOAEC for approxi mately 3-4 days. Residues on tall grass are never expected to exceed the NOAEC.

Table 28. Measured Concentration of Clofentezine After an Application of Apollo at 4 oz/acre (from MRID 45080701)
Days Post-Application Concentration of Clofentezine on Grapes (ppm)
0 0.79
1 0.41
3 0.75
7 0.45
14 0.34
21 0.2960 Figure 5. Expected decline of maximum clofentiz ine residues on foliage, in relation to the avian
and mammalian NOAEC values.

Also, the screening level risk assessment us ed values predicted by the T-REX model for maximum residue concentrations expected on wild life food items. These values represent the highest concentrations expected to be found on a treated field immediately after application (Fletcher et al., 1994). While it is possible th at a particular animal ma y feed in the area of the field with the maximum residues, the concentrati on that would be encountered by a typical bird would be better represented by the values T-RE X predicts for mean residue concentrations (Table 29). These values represent the mean of all concentrations expected in various places on a treated field immediately after application. As evident from Table 29, none of the mean
concentrations exceed the NOAEC fo r birds (30 mg/kg) or for mamma ls (50 mg/kg). Of course,
these residues would decline further as time after application increases. Thus, an animal feeding
in an area of the treated field wi th average residue concentrations is not expected to have any adverse effects to reprod uction or development.

Table 29. Dietary-Based Clofen tezine EEC Values Based on Pr edicted Mean Concentrations
Dietary Item Dietary-Based EEC (mg/kg)
Short Grass 22.10
Tall Grass 9.36
Broadleaf Plants 11.70 Fruits, Pods, and Seeds 1.82 Arthropods 16.90

In conclusion, the screening level risk assessm ent indicate that exposur e to clofentezine may cause adverse reproductive and developmental effect s to wildlife that feed on the treated field during a time when it is reproducing. However, this risk appears to be limited for the following

reasons: 0.00 10.00 20.00 30.00 40.00 50.00 60.00 70.00

0 5 10 15 20 25 30PredictedConcentration(ppm)

Days Short Grass

Broadleaf Plants

Tall Grass

Avian NOAEC

Mammalian NOAEC61  Maximum EECs fell between the NOAEC and LOAEC, and thus the studies did not
confirm that adverse effect s would occur at the EEC.

 Dietary-based risk assessment predicted risk only for animals whic h feed on short grass or broadleaf plants, but not other food items

 Clofentezine is applied only once per season, and clofentezine resi dues are not expected to remain above the NOAEC for very long after application (3 to 17 days). These factors limit the window of opportunity of e xposure to potentially toxic levels

 While maximum expected residue concen trations exceed the NOAEC for birds and mammals, mean residue concentrations do not.

2. Terrestrial Arthropods

As with any acaricide or insectic ide, clofentezine will pose some risk to nontarget terrestrial arthropods. However, the risks posed by clofentezine appear to be quite limited compared to
other acaricide or insecticide. The toxicity of clofentezine is specific to eggs and early larval stages, with very little toxicity to adult arthropods. Therefore, use of clofentezine will not pose a
risk to adult insects who feed on treated orchards, including worker bees and other insect pollinators such as butterflies and moths. Studies have shown that exposure to clofentezine at environmentally relevant exposure levels does redu ce fecundity and reduces su rvival of early life stages of beetles (Olszak, 1999; Samsoe-Peters on, 1993) and the honey bee (Yoshida and Fuchs, 1989). Yoshida and Fuchs (1989) found that clofent ezine has less reproductive toxicity to bees
than to Verroa mite, indicating that the toxicity is somewhat selective to mites.

Clofentezine may be applied only once per year, and clof entezine is not highly persistent in the environment. Therefore, any adverse effects th at may result to the re production of nontarget arthropods are expected to be transient and not have significant populatio n- or ecosystem-level effects. However, since some impairment of the reproduction of nontarge t insects and arachnids is possible, the EPA concludes that all uses of clofentezine may cause direct adverse to threatened and endangered terrestria l arthropods. Since the toxicity of clofentezine is specific to eggs and early life stages, listed species of terr estrial arthropods may be adversely affected, including those which would lay th eir eggs on trees or other vegetative plants in treated orchards and vineyards, and pollinators which would collect s nectar or pollen from flowers of treated plants during periods of reproduction.

3. Terrestrial Plants

A tier 1 vegetative vigor study found that exposure of four dicoty ledonous plants and two monocotyledonous plants to Apollo 50 SC at a maximum applicati on rate of 0.26 lb a.i./A caused no observable adverse effects (MRID 47192103). Expos ure by spray drift to nontarget terrestrial plants living outside the treatmen t site would be equal to or le ss than this application rate. Therefore, spray drift from all uses of clofent ezine are not expected to adversely affect the vegetative vigor of nontarget plants. The fact that no incidents of phytotoxicity damage have been reported for clofentezine is consistent with the conclusion that foliar exposure to
clofentezine is not harm ful to plants.62 No data are available on the effects of clof entezine on the germination and emergence of nontarget plants. Therefore, risk from inhibition of the germin ation and emergence of seeds is not known. However, the following lines of eviden ce suggest that clofente zine is not phytotoxic to plants:

 The mode of action of clofentezine is not relevant to toxicity of plants.

 A vegetative vigor study found no observable phytotoxicity at the maximum application

rate.

 Clofentezine is recommended for use on a wi de variety of woody and herbaceous plants in greenhouse use without a ny reported phytotoxicity.

Furthermore, clofentezine is applied only by ground equipment and has low mobility in soil, factors that limit exposure to nontar get plants via spray dr ift and runoff, respectively. Therefore,
the EPA assumes that use of clofentezine will not pose any risk to nontarget plants, and will not be harmful to listed species of terrestrial plants.

C. Ecological Incidents

A preliminary review of the Ecol ogical Incident Information Syst em (EIIS, version 2.1) in May 2012 did not identify any ecological incident of adverse field effects to nontarget plants or
animals which was attributed to use of clofen tezine. Also, review of the Avian Monitoring Information System (AIMS), which is maintain ed by the American Bird Conservancy, did not identify any ecological incident associat ed with the use of clofentezine.

In addition to the incidents reco rded in EIIS and AIMS, the Agen cy maintains a database which
stores counts of minor incidents th at pesticide registrants record in quarterly aggregated incident reports. Ecological incidents recorded in these aggregated reports include those categorized as ‘minor fish and wildlife’ (W-B), ‘minor plant’ (P-B), and ‘other non-target’ (ONT) incidents, which includes reports of adverse effects to bees and other invertebrates. A review of this database in May 2012 did not identify any minor in cident associated with use of clofentezine.

D. Uncertainties, Limitations, and Assumptions

1. Endocrine Disruption

As required by FIFRA and FFDCA, EPA reviews num erous studies to asse ss potential adverse outcomes from exposure to chemicals. Collectiv ely, these studies includ e acute, subchronic and chronic toxicity, including asse ssments of carcinogenicity, ne urotoxicity, developmental, reproductive, and general or systemic toxicity. These studies include endpoints which may be susceptible to endocrine influe nce, including effects on endocri ne target organ histopathology, organ weights, estrus cyclicity, sexual maturatio n, fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and chronic studies that assess gr owth, developmental and reprod uctive effects in different taxonomic groups. As part of the Preliminary Pr oblem Formulation for Registration Review (DP Barcode D336262)

, EPA reviewed these data and select ed the most sensitive endpoints for63 relevant risk assessment scenarios from the exis ting hazard database. However, as required by FFDCA section 408(p), clofentezine is subject to the endocrine sc reening part of the Endocrine Disruptor Screening Program (EDSP).

EPA has developed the EDSP to determine whet her certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an effect produced by a “naturally occurring estrogen, or ot her such endocrine effect s as the Administrator may designate.” The EDSP employs a two-tiered approach to making th e statutorily required
determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a chemical substance to interact with the estrog en, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go th rough Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal systems will proceed to the next stag e of the EDSP where EPA will determine which, if any, of th e Tier 2 tests are necessary base d on the available data. Tier 2 testing is designed to identify a ny adverse endocrine-related eff ects caused by the substance, and establish a dose-response relationship between the dose and the E, A, or T effect.

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 chemicals, which contains 58 pestic ide active ingredients and 9 inert ingredients. Clofentezine is not among the group of 58 pesticide active ingredient s on the initial list to be screened under the EDSP. Accordingly, as part of registration review, EPA will issu e future EDSP orders/data callins, requiring the submi ssion of EDSP screening assays for clofentezine

. For further information on the status of the EDSP, the policies and procedur es, the list of 67 chemi cals, future lists, the test guidelines and the Tier 1 screen ing battery, please visit our website: http://www.epa.gov/endo/

.

2. Uncertainties Related to Data Limitations

In the absence of available data to describe the adsorption-desorption of clofentezine in the soil,
EPI Suite was used to estimate the Koc of 516.1 L/kg. Although ther e are uncertainties associated with the estimated Koc, it predicts moderate mobility in soil and aquatic
environments.

Numerous limitations in the available toxicity da ta set contributed to uncertainty in this risk assessment. Chronic toxicity studies with fish were limited to early life-stage studies. These
studies measured toxic effects of clofentezine to eggs and larval stages , but did not evaluate potential impacts on the fecundity of adult female fish exposed to the compound. For aquatic invertebrates, several life-cycle studies were available, but they all suffered deficiencies that caused them to be classified as supplemental. In addition, two of the stud ies failed to test at levels low enough to establish an NOAEC. Because they failed to establish the chronic NOAEC, the lowest LOAEC value (44 μg/L from MRID 47192117) was used to assess risk to freshwater invertebrates. The study of chronic effects to the saltwater invertebrates (MRID 48342701) did produce an NOAEC, but the results were uncertain because the diluter system in the study failed
to deliver consistent concentrations of test so lution in the exposure cham bers. Finally, toxicity data were not available for some aquatic species, including estuarine mollusks ( e.g. , the oyster), sediment-dwelling arthropods, aquatic vascular plants, diatoms, a nd blue-green algae. These64 species may be more sensitive than the species wh ich were tested, and thus the risk assessment may have underestimated risk to aquatic invertebra tes and plants.

(Barber and Barrett, 1993) provi des data suggesting that repr oductive impairment observed in chronic studies with daphnids exposed to Apo llo SC, a suspension concentrate formulation of clofentezine, may be the result of physical st ress caused by ingestion of small solid particles while filter-feeding, rather than by inherent toxicity of clofentezi ne. The chronic endpoint used
in the freshwater invertebrate risk assessment was based on a life-cycle toxicity study conducted with Apollo 50 SC (MRID 47192102), and thus the observed toxicity may have been caused by exposure to suspended particles. Crustaceans liv ing in the wild exposed to clofentezine from runoff from treated areas would be exposed main ly to dissolved clofentezine, without the high concentration of suspended part icles present in the laboratory study. Thus, the study may have
overestimated chronic risk to fres hwater invertebrates in the wild.

The lack of complete phytotoxicity data for clof entezine also creates unc ertainty in the risk assessment for terrestrial plants. Only one vegetative vigor study has been submitted (MRID 47192103). That study was classified as supplemental because it tested only 6 plant species, whereas the guideline requires 10 species. No seedling emergence data have been submitted, therefore it was not possible to asse ss the risk of impairment of the germination or emergence of plants. Nevertheless, the risk assessment concluded that signif icant adverse effects to nontarget plants from use of clofentezine are unlikely (see Section VI.B.3.)

The lack of toxicity data on the two major degradation products that are expected to form in the environment also contributes to uncertainty in this risk assessme nt. Risk could be
underestimated if either of thes e degradates are significantly mo re toxic to nontarget organisms than the parent compound. QSAR analysis using the ECOSAR program does not predict significant toxicity for these de gradates with the possible excep tion of toxicity of AE C593600 to aquatic plants (Section II.E.3). ECOSAR resu lts provided contradictory predictions for the toxicity of AE C593600 to green algae based on comparisons with differe nt chemical classes (Table 12), and further evaluation led to the co nclusion that this compound is not likely to be very toxic to aquatic plants. However, risk co uld have been underestimated if AE C593600 is actually very toxic to aquatic pl ants (as suggested by one of th e ECOSAR predictions), or if either of the major degradate compounds is more toxic to any taxa of organisms than the QSAR analysis predicted.

3. Uncertainty in Risk Conclusions

The conclusion of “no effects” for threatened a nd endangered fish is not highly certain because the nondefinitive endpoint obtained for acute toxicity to fish was not sufficient to demonstrate that RQ is less than the LOC for endangered sp ecies (0.05) for use on fruit trees. Measurement
of the acute LC 50 for fish was limited by the solubility of clofentezine and thus only was shown to be greater than 34.2 μg/L. The LC 50 would need to be greater than 66.8 μg/L for the acute RQ
to be less than the 0.05. A conclusion of “no effe cts” was made based on the lack of toxic effects observed at the solubility limit of 34.2 μg/L, whic h is approximately 10 times greater than the65 peak EEC. Nevertheless, this conclusion would ha ve been more certain if all of the acute RQs
for fish were found to be less than the LOC of 0.05.

Finally, the conclusion that use of clofentezine will pose chronic risk to terrestrial wildlife is uncertain because chronic RQs we re only slightly great er than the LOC when considering the peak EEC, but would not exceed the LOC when cons idering the mean EEC. In some cases peak terrestrial EECs on wildlife food items exceeded the NOAEC for chronic effects, but in no case did they exceed the LOAEC. Chronic RQ s were calculated base d on the maximum EEC predicted by the T-REX model. If RQs were calculated based on mean EECs, which predict average residues expected throughout a treated fi eld, the RQs would not exceed the LOC. Also, as clofentezine may be applied only once per se ason, and terrestrial resi dues are expected to dissipate fairly rapidly, even the maximum EECs would be expected to remain at potentially toxic level for no more than 17 days for resi dues on short grass, or 4 days for residues on broadleaf plants (Fig. 5). In the chronic to xicity studies, test an imals were exposed to clofentezine for much longer dura tions than this (for example, approximately 22 weeks in the avian reproduction study). Thus, it is uncertain that the relatively short exposure that is expected to animals in the wild would produce as much ch ronic toxicity as observed in the laboratory
studies.

The risk assessment determined that risk exc eeds the EPA’s LOC only for chronic effects to
terrestrial animals. Because cl ofentezine may only be applied one time per year, the chronic terrestrial RQs cannot be reduced by limiting the nu mber of allowable applications or increasing the minimal application interval. Only reducing the single application ra te would reduce these chronic RQs. For protecting birds, the maximu m single application rate would need to be
reduced to <0.125 lb a.i./A to reduce the chroni c RQ to less than the chronic LOC (1). For protecting mammals, the single appl ication rate would need to be reduced even more, to <0.024 lb a.i./A, to reduce the RQ to less than the LOC.



### VII. Risk Conclusions

The results of this screening-level risk assessmen t indicate that all outdoor uses of clofentezine have the potential for direct adve rse effects to listed and non-liste d birds and mammals. As birds serve as surrogates to reptiles and terrestrial-phase amphibians, risk to these taxa is also possible.
Risk to terrestrial vertebrates is associated with sublethal effects on reproduction and growth that may occur with chronic exposure. Use of clofent ezine is not expected to pose a risk to foraging bees, but because of potential a dverse effects to reproduction a nd development, potentially may harm nonlisted and listed species of terrestrial arthropods. Use of cl ofentezine is not expected to
cause direct or indirect adverse e ffects to fish, aquatic invertebrate s, terrestrial plants, or aquatic plants.

Based on the available data, suspended concentrate (SC) formulated product s of clofentezine are slightly to practically non-toxic to freshwater fi sh and invertebrates on an acute-exposure basis. The limited solubility of the technical grade activ e ingredient (TGAI) prev ented classification of the acute toxicity, but the TGAI was shown to be nontoxic at concentrations that are close to the limit of its solubility in water. Acute RQs fo r fish and aquatic invertebrates were below the EPA’s LOC for listed and nonlisted species. Chr onic toxicity tests did not find any adverse66 effects caused by chronic exposure to fish at concen trations up to the solub ility limit. Chronic exposure to aquatic invertebrates was found to inhibit reproduction; however, the NOAEC in these studies were greater than expected envi ronmental concentrations (EECs), and thus the chronic RQs are all below EPA’s LOC.

For terrestrial birds and mammals, clofentezine is practically nontoxic on an acute exposure basis. The lack of toxicity a nd the relatively low use rate re sulted in acute risk quotients well below the EPA’s level of concern. However, chr onic studies identified a dverse sublethal effects
to birds and mammals. Because the NOAEL of these studies were less than the EEC for some types of birds and mammals, the chronic RQs were above the EPA’s LOC (dietary-based RQs 0.08 – 2.08, dose-based chronic RQs 0.07 – 10.83). Thus, all uses of clofentezine are predicted to pose chronic risk to birds, mammals, reptil es, and terrestrial amphibians, and may cause adverse effects listed species of these taxa. The chronic risk to terrestrial animals is not highly certain because (1) EECs did not exceed observed L OAECs and (2) clofentezine is not persistent in the terrestrial environment, and thus is likely to decline to below toxic levels rather quickly.

A honey bee contact study found that clofentezine is practically nontoxic to adult bees. Based on available acute toxicity data, no specific bee acute hazard statement is currently needed on product labels. Studies with bene ficial beetles have found that cl ofentezine also has low acute toxicity to these species. However, as with m ites (the target species), clofentezine has been found to cause toxicity to eggs and early life-stages of bees and other insects. While the available toxicity data and risk assessment methods do not allow for a precise description of the
chronic risk to terrestrial inse cts, a qualitative evaluation indi cates that potential risk of clofentezine use to cause significant brood effect s in bees is small. However, because of potential reproductive effects, the EPA believes that all uses of clof entezine have the potential to
cause adverse effects to nonlisted and liste d species of terres trial arthropods.

Because clofentezine is applied only once per year and residues are not very persistent in the environment, chronic effects to te rrestrial animals are not expected to be on a scale that would significantly affect thei r populations. Therefore indirect eff ects to endangered organisms from loss of ecological services, such as diminished seed dispersal of plants, are believed to be
discountable.

Several lines of evidence indicate that clofentezine has low toxicity to plants. Toxicity to plants is not expected by the mode of ac tion of this pesticide (toxicity to eggs and growth inhibition of early life-stages of invertebrates). Limit te sts conducted with terr estrial plants found no significant phytotoxicity when plan ts were treated directly at th e maximum application rate. A limit study testing the toxicity of a formulated pr oduct of clofentezine to green algae also found
no observable toxic effects when tested at th e high concentration of 100 mg product/L. Although other types of aquatic plants may be more sensit ive, and testing with other species of aquatic plants would be needed to draw general conclu sions for aquatic plants as a group, this test
indicates that clofentezine is not toxic to green algae at the sol ubility limit of clofentezine. Also, clofentezine is routinely applie d to a wide variety of plants in greenhouses, orchards, and tree farms without any reported problems with phytotoxici ty or plant dam age incidents. Therefore, EPA concludes that use of clofentezine will not po se significant risk to either terrestrial or aquatic plants, and is not expected to harm listed species of plants.67 Conclusions on the potential for clofentezine to ca use direct and indirect effects to federally listed threatened and endangere d species of various taxa ar e summarized in Table 30. Conclusions for direct effects to listed species are also summarized in Table 1 of the Executive Summary.

Table 30. Non-listed and Listed Species Risks A ssociated with Potentia l Direct or Indirect Effects Due to the Applica tions of Clofentezine

LISTED TAXON DIRECT EFFECTS INDIRECT
EFFECTS 1 Non-listed Listed

Terrestrial and semi-aquatic plants

– monocots No No No

Terrestrial and semi-aquatic plants
– dicots No No No

Birds Yes Yes Yes

Terrestrial phase amphibians Yes Yes Yes

Reptiles Yes Yes Yes

Mammals Yes Yes Yes

Terrestrial Invertebrates Yes Yes Yes

Aquatic plants No No No

Freshwater fish No No No

Aquatic phase amphibians No No No

Freshwater crustaceans No No No

Mollusks 2 No No No

Marine/estuarine fish 2 No No No

Marine/estuarine crustaceans 2 No No No

1 Indirect effects may include general habitat modification, host plant loss, and food supply disruption.

2 Quantitative data are not available for saltwater invertebrate s, therefore RQs were not calculated. Risk conclusions were based on risk quotients calculated for freshwater invertebrates.68 

### VIII. References

Barber, I. and K. Barrett. 1993. Th e effect of a pesticide suspen sion concentrate formulation on Daphnia magna Straus reproduction. Sci. Total Environ ., 134 (Suppl. 2): 853-858.

BEAD, 2012. Usage/Use Report Package in Support of Registration Review for Clofentezine

. Memorandum from Biological and Economic Analysis Branch to Pesticide ReEvaluation Division. March 01, 2012.

Clements, R.G., J.V. Nabholz, and M. Zeeman. 1996. Estimating toxicity of industrial chemicals to aquatic organisms using stru cture-activity relationships . Ed.: R.G. Clements.

IRAC. 2012. IRAC MoA Classification Scheme . Version 7.2. IRAC Inte rnational MoA Working Group. 23 pp. Available online at: http://www.irac-online.org/cont ent/uploads/MoA-classification.pdf

JMPR, 2007. Pesticide Residues in Food 2007, Evaluations Part 1 – Residues . Joint Meeting of the FOA Panel of Experts on Pesticide Residues in Food and the Environment and the WHO Core Assessment Group, Geneva, Switzerland, 18-27 2007. FAO Plant Production and Protection Paper 192. World Health Organization and Food and Agriculture Organization of the United Nations . Rome, 2008. Available online at: http://www.fao.org/ag/AGP/AGPP/Pesticid /JMPR/Download/2007_eva/Evaluation.pdf

Lentz, Nancy R. 2010a. [14C ] Clofentezine – Aerobic A quatic Sediment Metabolism, Springborn Smithers Laboratories, Wareham, Massachusetts, Sponsor ed by Irvita Plant Protection N.V. c/o Makhteshim–Agan of No rth America Inc. 4515 Falls of Neuse Rd., Suite 300, Raleigh, NC, USA, 27609 . Study No. 11742.614746J, 135 p. PMRA 2060524

Lentz, Nancy R. 2010b. [14C]Clofentezine – Anaerobic Aquatic Sediment Metabolism, Springborn Smithers Laboratories, Wareham, Massachusetts, Sponsor ed by Irvita Plant Protection N.V. c/o Makhteshim–Agan of No rth America Inc. 4515 Falls of Neuse Rd., Suite 300, Raleigh, NC, USA, 27609. Study No. 11742.6148, 134 p. PMRA 2060525.

Olszak, R.W. 1999. Influence of some pesticides on mortality and fecundity of the aphidophagous coccinellid Adalia bipunctata L (Col., Coccinellidae). J. Appl. Ent.
123:41-45.

Samsoe-Petersen, L. 1993. Effects of 45 Insecticid es, Acaricides and Molluscicides on the Rove Beetle Aleochara bilineata (Col.: Staphylinidae) in the Laboratory. Entomophaga 38(3):
371-382.

USEPA, 1990. National Survey of Pesticides in Drinking Water Wells. Report Number: USEPA 570/9-90-015, USEPA Office of Water, Washington, DC.

USEPA, 1992. Pesticides in Ground Water Data Base. Report Numbe r(s): PB-89-164230/XAB; EPA-540/9-89/036, Environmental Protection Ag ency, Washington, DC (USA). Office of Pesticide Programs69 USEPA, 2004. Overview of the Ecological Risk Assessm ent Process in the Office of Pesticide Programs . United States Environmental Protection Agency (USEPA). Environmental
Fate and Effects Division. Office of Pesticide Programs. Available at http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

USEPA, 2012. EFED Problem Formulation for Cl ofentezine Registration Review

. Memorandum from the Environmental Fate and Effects Division to the Registration Division, Office of Pesticid e Programs, Office of Chemical Safety and Pollution Prevention. February 2, 2007.

USEPA, 2012. OCSPP 850.3020: Honey Bee Ac ute Contact Toxicity . Ecological Effects Test Guideline. Office of Chemical Safety a nd Pollution Prevention. EPA 712-C-019. January
2012.

Yoshida, T. and S. Fuchs. 1989. Blocking reproduction in Verroa jacobsoni Oud. by feeding clofentezine with pollen to its host Apis mellifera L. J. Appl. Ent. 108:519-526.70 

### APPENDIX A

Clofentezine (125501) Screening Level Usage Analysis (SLUA) Date: February 17, 2012

What is a Screening Level Usage Analysis (SLUA)?

 Available estimates of pesticide usage data for a particular active ingredient that is
used on agricultural crops in the United States.

 Pesticide usage data obtained from various sources. The data are then merged, averaged, and rounded so that the presente d information is not proprietary, business confidential, or trade secret.
What does it contain?

 Pesticide usage data for a single active ingredient only.

 Agricultural use sites (cr ops) that the pesticide is reported to be used on.

 Available pesticide usage information from U. S. states that produce 80% or more of a crop, in most cases, or less than 80%, in rare cases, depending on the scope of the survey and available resources.

 Annual percent of crop treated (average & maximum) for each agricultural crop.

 Average annual pounds of the pesticide applied for each agricultural crop (i.e., for the states surveyed, not for the entire United States). What assumptions can I make about the reported data?

 Average pounds of active ingredient applied - Values are calculated by merging pesticide usage data sources together; averaging across all observations, then rounding. Note: If the estimated value is less th an 500, then that value is labeled
<500. Estimated values between 500 & <1,000,000 are rounded to 1 significant digit. Estimated values of 1,000,000 or grea ter are rounded to 2 significant digits.)

 Average percent of crop treated - Values are calculated by merging data sources together; averaging by year, averaging acr oss all years, & rounding to the nearest multiple of 5. Note: If the estimated value is less than 2.5, then the value is labeled <2.5. If the estimated va lue is less than 1, then th e value is labeled <1.

 Maximum percent of crop treated - Value is the single maximum value reported across all data sources, across all years, & rounded up to the nearest multiple of 5.
Note: If the estimated valu e is less than 2.5, then th e value is labeled <2.5.
What are the data sources used?

 USDA-NASS (United States Department of Agriculture ’s National Agricultural Statistics Service) – pesticid e usage data from 2003 to 2010.

 Private pesticide market research – pesticide usage data from 2003 to 2010.

 California Department of Pesticide Regu lation (DPR) Pesticide Use Reporting (PUR) data for 2003 to 2010.
What are the limitations to the data?

 Additional registered uses may exist but are not included because the available surveys do not report usage (e.g., small acreage crops).

 Lack of reported usage data for the pesticide on a crop does not imply zero usage.71  Usage data on a particular site may be noted in data sources, but not quantified . In these instances, the site would not be reported in the SLUA.

 Non-agricultural use sites (e.g., turf, post-ha rvest, mosquito control, etc.) are not reported in the SLUA. A separate request must be made to receive these estimates.

 Some sites show some use, even though they are not on the label. This usage could be due to various factors, including, but not limited to Section 18 requests, existing stocks of the chemical, data collection errors , and experimental use permits (EUPs).72 February 17, 2012

Screening Level Estimates of Agricult ural Uses of Clofentezine (125501) Sorted Alphabetically

Crop

Lbs. A.I. Percent Crop Treated
Average Maximum
1 Almonds 3,000 <2.5 5
2 Apples 1,000 <2.5 10
3 Apricots <500 <2.5 <2.5
4 Cherries 1,000 5 10
5 Grapes <500 <1 <2.5
6 Nectarines <500 5 10
7 Peaches 1,000 5 15
8 Pears <500 5 10
9 Plums/Prunes + <500 <2.5 <2.5
10 Walnuts 2,000 5 10

All numbers rounded. <500 Less than 500 pounds of active ingredient <2.5 Less than 2.5 percent of crop treated

<1 Less than 1 percent of crop treated ** California data only. No information available about use of this chemical on this crop in
other states.

+ Crops not known to be listed on active end use product registrations or as Section 18

emergency exemptions when this report was run

SLUA data sources include: USDA-NASS (United States Department of Agriculture's National Agricultural Statistics Service)
Private Pesticide Market Research California DPR (Department of Pesticide Regulation)

These results reflect amalgamated data developed by the Agency and are releasable to the public.73 

### APPENDIX B

Structures of Clofentezine Degradates74 

### APPENDIX C

PRZM/EXAMS Aquatic EECs Output File

Upper 10th Percentile Limnetic EECs in Farm Pond

Chemical - Clofentezine

Scenarios Instantaneous 96-Hour 21-Day 60-Day 90-Day Annual

RUN ID: NC1App-P

RUN ID: MI1Che-P

RUN ID: NY2Gra-P

RUN ID: PA1App-P

RUN ID: OR1Xma-P

RUN ID: GA1Pch-P

RUN ID: OR1App-P

RUN ID: CA1Wal-P

RUN ID: CA1Gra-P

RUN ID: CA1Orc-P 3.34

1.04

1.02

0.996

0.964

0.832

0.726

0.454

0.170

0.139 1.48

0.460

0.453

0.477

0.377

0.363

0.413

0.210

0.745E-01

0.642E-01 0.406

0.156

0.170

0.128

0.123

0.929E-01

0.155

0.705E-01

0.214E-01

0.173E-01 0.145

0.605E-01

0.742E-01

0.558E-01

0.430E-01

0.361E-01

0.723E-01

0.265E-01

0.862E-02

0.709E-02 0.967E-01

0.423E-01

0.514E-01

0.400E-01

0.287E-01

0.241E-01

0.490E-01

0.218E-01

0.756E-02

0.475E-02 0.239E-01

0.105E-01

0.130E-01

0.988E-02

0.902E-02

0.594E-02

0.122E-01

0.594E-02

0.204E-02

0.190E-02

Express v. 1.03.02 (2007-07-20) - Exams 2.98.04.06 with PRZM 3.12.2[48]75 

### APPENDIX D

Output from T-Rex Model Run for Clofentezine

Acute and Chronic RQs are based on the Upper Bound

Kenaga Residues.76 Chemical Name: Clofentezine The maximum single day residue estimation is used for

Use All both the acute and reproduction RQs.

Formulation 0

Application Rate 0.26 lbs a.i./acre RQs reported as "0.00" in the RQ tables below should be noted as

Half-life 15.7 days <0.01 in your assessment. This is due to rounding and significant

Application Interval 0 days figure issues in Excel.

Maximum # Apps./Year 1

Length of Simulation 1 year Variable application rates? no

Endpoints

Avian Bobwhite quail LD50 (mg/kg-bw) 3000.00

Bobwhite quail LC50 (mg/kg-diet) 19900.00
Mallard

duck NOAEL(mg/k g-bw) 0.00

Bobwhite quail NOAEC (mg/kg-diet) 30.00

Mammals LD50 (mg/kg-bw) 3230.00 LC50 (mg/kg-diet) 0.00 NOAEL (mg/kg-bw) 2.50 NOAEC (mg/kg-diet) 50.0077 Dietary-based EECs (ppm) Kenaga
Values Short Grass 62.40 Tall Grass 28.60 Broadleaf plants 35.10 Fruits/pods/seeds 3.90 Arthropods 24.44



### Avian Results

Avian Body Ingestion (Fdry) Ingestio n (Fwet) % body wgt FI

Class Weight (g) (g bw/day) (g/day) consumed (kgdiet/day)

Small 20 5 23 114 2.28E-02

Mid 100 13 65 65 6.49E-02

Large 1000 58 291 29 2.91E-01

20 5 5 25 5.06E-03

Granivores 100 13 14 14 1.44E-02

1000 58 65 6 6.46E-02

Avian Body Adjusted LD50

Weight (g) (mg/kg-bw)

20 2161.29

100 2751.43

1000 3886.5078 Dose-based EECs (mg/kg-bw) Avian Classes and Body Weights (grams)

small mid large

20 100 1000

Short Grass 71.07 40.53 18.14

Tall Grass 32.57 18.57 8.32 Broadleaf plants 39.98 22.80 10.21

Fruits/pods 4.44 2.53 1.13

Arthropods 27.83 15.87 7.11

Seeds 0.99 0.56 0.25

Dose-based RQs(Dosebased EEC/adjust ed LD50) Avian Acute RQs Size Class (grams)

20 100 1000

Short Grass 0.03 0.01 0.00

Tall Grass 0.02 0.01 0.00 Broadleaf plants 0.02 0.01 0.00

Fruits/pods 0.00 0.00 0.00

Arthropods 0.01 0.01 0.00

Seeds 0.00 0.00 0.0079Dietarybased RQs(Dietarybased EEC/LC50 or NOAEC) RQs

Acute Chronic

Short Grass 0.00 2.08

Tall Grass 0.00 0.95 Broadleaf plants 0.00 1.17 Fruits/pods/
seeds 0.00 0.13

Arthropods 0.00 0.81

Note: To provide risk management with the maximum possible information, it is recommende d that boththe dosebased andconcentrationbased RQs be
calculated when data are available80 Clofentezine All Upper bound Kenaga Residues 

## Mammalian Results

Mammalian Body Ingestion (Fdry) Ingestion (Fwet) % body wgt FI

Class Weight (g bwt/day) (g/day) consumed (kgdiet/day)
15 3 14 95 1.43E-02 Herbivores/ 35 5 23 66 2.31E-02 insectivores 1000 31 153 15 1.53E-01
15 3 3 21 3.18E-03 Grainvores 35 5 5 15 5.13E-03
1000 31 34 3 3.40E-02

Mammalian Body Adjusted Adjusted Class Weight LD50 NOAEL
15 7098.99 5.49 Herbivores/ 35 5743.84 4.45 insectivores 1000 2484.39 1.92
15 7098.99 5.49 Granivores 35 5743.84 4.45
1000 2484.39 1.92

Dose-Based EECs (mg/kg-bw) Mammalian Classes and Body weight (grams)

15 35 1000

Short Grass 59.49 41.12 9.53 Tall Grass 27.27 18.85 4.37 Broadleaf plants 33.47 23.13 5.36 Fruits/pods 3.72 2.57 0.60 Arthropods 23.30 16.10 3.73 Seeds 0.83 0.57 0.13

Dose-based RQs (Dose-based EEC/LD50 or NOAEL) Small mammal Medium mammal Large mammal

15 grams 35 grams 1000 grams

Acute Chronic A cute Chronic Acute Chronic

Short Grass 0.01 10.83 0.01 9.25 0.00 4.96 Tall Grass 0.00 4.96 0.00 4.24 0.00 2.27 Broadleaf plants 0.00 6.09 0.00 5.20 0.00 2.79 Fruits/pods 0.00 0.68 0.00 0.58 0.00 0.31 Arthropods 0.00 4.24 0.00 3.62 0.00 1.94 Seeds 0.00 0.15 0.00 0.13 0.00 0.0781 Dietary-basedRQs (Dietarybased EEC/LC50 or NOAEC) Mammal RQs

Acute Chronic

Short Grass #DIV/0! 1.25 Tall Grass #DIV/0! 0.57 Broadleaf plants #DIV/0! 0.70 Fruits/pods/seeds #DIV/0! 0.08 Arthropods #DIV/0! 0.49

Note: To provide risk management with the maximum possible information, it is recommendedthat both the dosebased andconcentrationbased RQs be calculated
when data are available82 

### APPENDIX E

Output from the Screening Imbibition Program (SIP) for Clofentezine

Table 1. Inputs

Parameter Value
Chemical name Clofentezine Solubility (in water at 25 o C; mg/L) 0.002

Mammalian LD 50 (mg/kg-bw) 3230 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 20 Mammalian test species laboratory rat Body weight (g) of "other" mammalian species

Avian LD 50 (mg/kg-bw) 3000 Avian test species mallard duck Body weight (g) of "other" avian species Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 270 Bobwhite quail NOAEC (mg/kg-diet) 30 NOAEC (mg/kg-diet) for other bird species Body weight (g) of other avian species NOAEC (mg/kg-diet) for 2nd other bird species Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 0.0003 0.0003 Adjusted toxicity value (mg/kg-bw) 2484.3886 15.3832 Ratio of exposure to toxicity 0.0000 0.0000

Conclusion* Drinking water exposure alone is NOT a potential

concern for mammals Drinking water exposure alone is NOT a potential

concern for mammals83 Table 3. Avian Results

Parameter Acute Chronic Upper bound exposure (mg/kg-bw) 0.0016 0.0016 Adjusted toxicity value (mg/kg-bw) 1557.6762 3.1889 Ratio of exposure to acute toxicity 0.0000 0.0005

Conclusion* Drinking water exposure alone is NOT a potential concern for birds Drinking water exposure alone is NOT a potential concern for birds

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. Therefore, when aggregated with other routes ( i.e ., diet, inhalation, dermal), pesticide exposure through drinking water may contribute to a total exposure that has potential for effects to non-target animals.84 

### APPENDIX F

Output from the Screening Tool for Inhalation Risk (STIR) for Clofentezine



## Welcome to the EFED Screening Tool for Inhalation Risk
This tool is designed to provide the risk assessor with a rapid method for determining the potential significance of the inhalation exposure route to birds and mammals in a risk
assessment.



## Input

Application and Chem ical Information

Enter Chemical Name Clofentezine
Enter Chemical Use all Is the Application a Spray? (enter y or n) y If Spray What Type (enter ground or air) ground
Enter Chemical Molecu lar Weight (g/mole) 303.15 Enter Chemical Vapor Pressure (mmHg) 9.75E-10 Enter Application Rate (lb a.i./acre)

Toxicity Properties

Bird

Enter Lowest Bird Oral LD 50 (mg/kg bw) 3000 Enter Mineau Scaling Factor 1.15 Enter Tested Bird Weight (kg) 1.58

Mammal

Enter Lowest Rat Oral LD 50 (mg/kg bw) 3200

Enter Lowest Rat Inhalation LC 50 (mg/L) 9.08 Duration of Rat Inhalation Study (hrs) 6 Enter Rat Weight (kg) 0.3585 

## Output
Results Avian (0.020 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 1.59E-05 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.00E-06
Adjusted Inhalation LD 50 5.13E+01
Ratio of Vapor Dose to Adjusted Inhalation LD 50 3.90E-08 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 0.00E+00 Ratio of Droplet Inhalation Dose to Adjusted Inhalation
LD 50 0.00E+00 Exposure not Likely Significant

Results Mammalian (0.015 kg ) Maximum Vapor Concentration in Air at Saturation (mg/m 3 ) 1.59E-05 Maximum 1-hour Vapor Inhalation Dose (mg/kg) 2.51E-06
Adjusted Inhalation LD 50 8.11E+02
Ratio of Vapor Dose to Adjusted Inhalation LD 50 3.10E-09 Exposure not Likely Significant Maximum Post-treatment Spray Inhalation Dose (mg/kg) 0.00E+00 Ratio of Droplet Inhalation Dose to Adjusted Inhalation
LD 50 0.00E+00 Exposure not Likely Significant86 

### APPENDIX G

Results of ECOTOX Literature Search for Clofentezine

Open literature studies with toxicity data on clofentezine were identified using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007 c ), which employs a literature search engine for locating chemical toxi city data for aquatic life, terrestrial plants, and wildlife.

Accepted for EcoTox and OPP

Bostanian, N. J., Vincent, C., Pitre, D., and Simard, L. G. (1989). Chemical Control of Key and Secondary Arthropod Pests of Quebec Apple Orchards. Appl. Agric. Res. 4(3): 179-184.
EcoReference No.: 89749 Chemical of Concern: ACYP,AZ,BFT,CHX,CTZ,CYH,CYP,DM,FNV,FVL,HTX,OTQ,TDC; Habitat: T;
Effect Codes : POP; Code: LITE EVAL CODED (AZ,BFT,CTZ,CYH,CYP,DM,FNV,FVL,HTX,TDC), NO EFED CHEM (ACYP,CHX,OTQ)

Easterbrook, M. A. (1984). Effects of Pesticides on the Apple Rust Mite Aculus schlechtendali (Nal.) (Eriophyidae).
J. Hortic. Sci. 59(1): 51-55.
EcoReference No.: 71031
Chemical of Concern: AMZ,CBL,CHX,CPY,CTZ,DCF,DFZ,ES,FPP,FRM,MZB,PHSL,PIRM,PPG,SFR,TDF,TFR; Habitat: T;
Effect Codes : POP; Code: LITE EVAL CODED (AMZ,CBL,CTZ,DCF,DFZ,FPP,FRM,MZB,PIRM,PPG,SFR ,TDF,TFR), NO EFED CHEM (CHX,PHSL), TARGET (CPY,ES)

Fouche, C., Verdegaal, P., Duncan, R., and Cutter, D. (1998). Evaluation of Acaricides for Control of Spider Mites on Almonds and Impact on Two Beneficial Arthropods, 1997. Arthropod Manag. Tests 23: 59-(1D).
EcoReference No.: 150672 Chemical of Concern: ABM,CFP,C TZ,EXZ,HTX,NMO,PPG,PRB; Habitat: T; Effect Codes : POP; Code: LITE EVAL CODED (CTZ), NO EFED CHEM (E XZ), OK (ABM,CFP,HTX,NMO,PPG,PRB)

Goodwin, S. (1984). Laboratory Evaluation of Pesticides on an Australian Strain of the Chilean Predatory Mite, Phytoseiulus persimilis Athias-Henriot. In: D.A.Griffiths and C.E.Bowman (Eds.), Acarology VI, Vol. 2, Ellis Horwood, Chichester, UK 2: 647-654.
EcoReference No.: 94828
Chemical of Concern: AZ,BMY,BTN,CHX,CPY,CTZ,Captan,DCF,DIE,DM T,DZ,ES,FBOX,FNV,FO,IPD,MDT,MLN,MZB,OT Q,OXC,PIM,PMR,PPG,SFR,TCF,TDF,TFR,VCZ; Habitat: T; Effect Codes : MOR,REP; Code: LITE
EVAL CODED (AZ,BMY,CPY,CTZ,Captan,DCF ,DMT,DZ,ES,FBOX,FNV,IPD,MD T,MLN,MZB,PIM,PMR,PPG,SFR,T CF,TDF,TFR,VCZ), NO EFED CHEM (BTN,CHX,DIE,OTQ,OXC)

Olszak, R. W. (1999). Influence of Some Pesticides on Mortality and Fecundity of the Aphidophagous Coccinellid Adalia bipunctata L. (Col., Coccinellidae). Z. Angew. Entomol. 123(1): 41-45.
EcoReference No.: 64265
Chemical of Concern: ACYP,AMZ,CTZ,DFC,DOD,EFV,ES,FBOX,FO,FPP,FRM,FUZ,HTX,IPD,MEM,MZB,PHSL,PPG,TFR, TFZ,VCZ; Habitat: T; Effect Codes : MOR,REP; Code: LITE EVAL CODED (DOD,EFV,ES,FRM,FUZ,IPD,MEM,MZB,VCZ,CTZ), NO EFED CHEM (ACYP,DFC,PHSL), NO ENDPOINT (HTX,TFZ), TAR

Samsoe-Petersen, L. (1993). Effects of 45 Insecticides, Acaricides and Mollu scicides on the Rove Beetle Aleochara87 bilineata (Col.: Staphylin idae) in the Laboratory. Entomophaga 38(3): 371-382.

EcoReference No.: 63489
Chemical of Concern: ACP,AMZ,AZ,BPZ,CBL,CPY,CTZ ,CYF,CYP,CYR,DFZ,DM,DMT,DZ,FNT,FPP,FVL,FYC,HTX,KSP,L CYT,MAL,MCB,MTM,MVP,OML,OTQ,PIM,PMR,PPHD,PSM,THO; Habitat: T; Effect Codes : MOR,REP; Code: LITE EVAL CODED (CBL,CPY,CTZ,CYF,CYP,CYR,DFZ,DMT,DZ,FPP,FVL,FYC,HTX,KSP,LCYT,MAL,MCB,MTM,MVP ,OML,PIM,PMR,PSM), NO EFED CHEM (BPZ,OTQ,PPHD,THO), NO PUBL AS (ACP,AMZ,AZ,DM,FNT), TARGET (AMZ,AZ,DM,FNT)

Urbaneja, A., Pascual-Ruiz, S., Pina, T., Abad-Moyano, R., Vanaclocha, P., Monton, H., Dembilio, O., Castenera, P., and Jacas, J. A. (2008). Efficacy of Five Sel ected Acaricides Against Tetranychus urticae (Acari: Tetranychidae) and Their Side Ef fects on Relevant Natural Enemies Occurring in Citrus Orchards. Pest Manag. Sci. 64(8): 834-842.
EcoReference No.: 154868 Chemical of Concern: ALSV,CTZ,FBOX,FZQ,MOIL,TFY; Habitat: T; Effect Codes : MOR,POP,REP;
Code: LITE EVAL CODED (ALSV,CTZ,FBOX,FZQ,MOIL,TFY), NO EFED CHEM (TFY)

Yoshida, T. and Fuchs, S. (1989). Blocking Reproduction in Varroa jacobsoni Oud. by Feeding Clofentezin with Pollen to Its Host Apis mellifera L. J. Appl. Entomol. : 519-526.
EcoReference No.: 154863 Chemical of Concern: CTZ; Habitat: T; Effect Codes : GRO,MOR,REP; Code: LITE EVAL CODED (CTZ)

Papers not Accepted for ECOTOX

Hull, L. A. and Krawczyk, G. (1998). Tufted Ap ple Bud Moth Control Tactics for Apple, 1997. Arthropod Manag.
Tests 23: 22-26 (15A).
EcoReference No.: 150741 Chemical of Concern: ABM,ALSV,CTZ,IMC ,MFZ,MOIL,MOM,MP,PYX,SS,TUZ; Habitat: T; Effect
Codes : POP; Code: NO EFED CHEM (SS), NO MIXTURE (ABM,CTZ,IMC,MFZ,MOM,MP,TUZ), TARGET (ALSV,MOIL,PYX,TUZ)

Longhurst, C., Bacci, L., Bue ndia, J., Hatton, C. J., Petitp rez, J., and Tsakonas, P. (1992). Fenazaquin, a Novel Acaricide for the Management of Spider Mites in a Variety of Crops. In: Br.Crop Prot.Counc., Brighton Crop Prot.Conf.: Pests and Diseases, Vol.1-3, Int.Co nf., Nov.23-26, 1992, Brighton, England, UK, Br.Crop Prot.Counc.(BCPC), Farnham, England, UK : 51-58.
EcoReference No.: 106270 Chemical of Concern: BFT,CTZ,DCF,FBOX,FPP,FZQ,HTX,PPG; Habitat: T; Effect Codes : PHY,POP;
Code: NO CONTROL (BFT,CTZ), NO ENDPOINT (FBOX,HTX,PPG), OK (DCF,FPP,FZQ)

Maciesiak, A. and Olszak, R. W. (1999). Effectiveness of Acaricide Mixtures in the Control of Phytophagous Mites on Apple Trees. J. Fruit Ornam. Plant Res. 7(2): 91-96.
EcoReference No.: 97506 Chemical of Concern: AMZ,CTE,CTZ,HTX,PPG; Habitat: T; Effect Codes : POP; Code: LITE EVAL CODED (PPG), NO MIXTURE (AMZ,CTZ), TARGET (HTX)

Somerville, L., Challis, I. R., and Needham, D. (1989) . Relevance of Kinetic and Metabolic Data to the Interpretation of Toxicological Findings. Food Addit. Contam. 6(1): 33-39.
EcoReference No.: 150077 Chemical of Concern: CTZ; Habitat: T; Effect Codes : ACC; Code: NO CONTROL (CTZ), NO ENDPOINT (CTZ)

Van Leeuwen, T., Stillatus, V., and Tirry, L. U. C. (20 04). Genetic Analysis and Cross-Resistance Spectrum of a Laboratory-Selected Chlorfenapyr Re sistant Strain of Two-Spotted Spider Mite (Acari: Tetranychidae).88 Exp. Appl. Acarol. 32(4): 249-261.

EcoReference No.: 75967 Chemical of Concern: AMZ,BF T,CFP,CTZ,DMT,PPB,SDF; Habitat: T; Effect Codes : MOR; Code: NO CONTROL (AMZ,BFT,CFP,CTZ,DMT,SDF), NO MIXTURE (PPB)