
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            WASHINGTON, D.C.  20460
                                                                      OFFICE OF
                                                            CHEMICAL SAFETY AND
\* MERGEFORMAT
                                                           POLLUTION PREVENTION


MEMORANDUM

Date:		August 6, 2013

SUBJECT:	Methoxyfenozide.  Human Health Risk Assessment to Support Proposed New Uses on Herbs, Caneberries, Dates and Sorghum; to Establish Rotational Crop Tolerances in the Rapeseed and Sunflower Oilseed Subgroups; as well as to extend and update Crop Group Tolerances on Multiple Commodities.  
 
PC Code:  121027 
DP Barcode:  D407285
Decision No.:  472142
Registration No.:  62719-442; 13-CA-09
Petition No.:  2E8118
Regulatory Action:  Section 3 Registration; Section 18 Registration (Dates only)
Risk Assessment Type:  Single Chemical Aggregate
Case No.:  7431
TXR No.:  NA
CAS No.:  161050-58-4
MRID No.:  NA
40 CFR:  180.544


FROM:	Elizabeth Holman, Physical Scientist/Risk Assessor
		Margarita Collantes, Biologist
      William Drew, Chemist
      Linnea J. Hansen, Ph.D., Biologist	
		Risk Assessment Branch II (RABII)
		Health Effects Division (7509P)

THROUGH:	Christina Swartz, Branch Chief
		Risk Assessment Branch II (RABII)
		Health Effects Division (7509P)

TO:		Laura Nollen/Barbara Madden, RM Team 05
		Risk Integration Minor Use, and Emergency Response Branch (RIMUERB)
		Registration Division (7505P)

The Registration Division (RD) requested that the Health Effects Division (HED) conduct a risk assessment for the active ingredient methoxyfenozide to estimate the risk to human health that will result from proposed new uses on herbs (subgroup 19A) except chives, caneberry (subgroup 13-07A), date, and sorghum.  In addition, this assessment also updates existing tolerances for multiple commodities; specifically, tolerances in the updated crop groups 8-10 and 11-10, and in the updated subgroups 13-07F and 13-07G were requested.  Tolerances in sugar apples, cherimoyas, atemoyas, custard apples, ilamas, soursops, and biribas were also requested, based on translation of avocado residues.  Additionally, indirect or inadvertent tolerances in the rapeseed subgroup (20A) and the sunflower subgroup (20B) were requested.  While the proposed Section 3 use on dates was undergoing review in the Agency, the state of California submitted a Section 18 Specific Emergency Exemption request for use of methoxyfenozide on dates to control carob moth.  The proposed use pattern in CA is the same as the use pattern proposed for Section 3 registration, and therefore this risk assessment addressed the proposed S18 use.

The attached human health risk assessment addresses exposure and risk associated with the proposed uses, revisions to existing tolerances, as well as the existing use on ornamentals.  The exposures assessed include dietary (food and water), inhalation for occupational workers and residential handlers, and aggregate exposure and risk for residential handlers resulting from use on ornamentals.  There were no risks of concern identified for any route or duration of exposure.

                               Table of Contents
1.0	Executive Summary	5
2.0	HED Recommendations	7
2.1	Data Deficiencies/Conditions of Registration	7
2.2	Tolerance Considerations	7
2.2.1	Enforcement Analytical Method	7
2.2.2	International Harmonization	8
2.2.3	Recommended Tolerances	8
2.2.4	Revisions to Petitioned-For Tolerances	10
2.3	Label Recommendations From Residue Review	10
3.0	Introduction	11
3.1	Chemical Identity	12
3.2	Physical/Chemical Characteristics	12
3.3	Pesticide Use Pattern	12
3.4	Anticipated Exposure Pathways	14
3.5	Consideration of Environmental Justice	14
4.0	Hazard Characterization and Dose-Response Assessment	15
4.1	Toxicology Studies Available for Analysis	15
4.2	Absorption, Distribution, Metabolism, & Elimination (ADME)	15
4.2.1	Dermal Absorption	16
4.3	Toxicological Effects	16
4.4	Safety Factor for Infants and Children (FQPA Safety Factor)	18
4.4.2	Evidence of Neurotoxicity	18
4.4.3	Evidence of Sensitivity/Susceptibility in the Developing or Young Animal	18
4.5	Toxicity Endpoint and Point of Departure Selections	19
4.5.1	Dose-Response Assessment	19
4.5.2	Recommendation for Combining Routes of Exposures for Risk Assessment	20
4.5.3	Cancer Classification and Risk Assessment Recommendation	21
5.0	Dietary Exposure and Risk Assessment	23
5.1	Metabolite/Degradate Residue Profile	23
5.1.1	Summary of Plant and Animal Metabolism Studies	23
5.1.2	Summary of Environmental Degradation	24
5.1.3	Comparison of Metabolic Pathways	24
5.1.4	Residues of Concern Summary and Rationale	24
5.2	Food Residue Profile	26
5.3	Water Residue Profile	27
5.4	Dietary Risk Assessment	28
5.4.1	Description of Residue Data Used in Dietary Assessment	28
5.4.2	Percent Crop Treated Used in Dietary Assessment	29
5.4.3	Acute Dietary Risk Assessment	29
5.4.4	Chronic Dietary Risk Assessment	29
5.4.5	Cancer Dietary Risk Assessment	30
6.0	Residential (Non-Occupational) Exposure/Risk Characterization	30
6.1	Residential Handler Exposure	30
6.2	Dermal Post-application Exposure	31
6.5	Spray Drift	32
7.0	Aggregate Exposure/Risk Characterization	32
7.1	Acute Aggregate Risk	32
7.2	Short-Term Aggregate Risk	32
7.3	Chronic Aggregate Risk	33
8.0	Cumulative Exposure/Risk Characterization	33
9.0	Occupational Exposure/Risk Characterization	33
9.1	Occupational Handlers	34
9.2	Post-application Risk	36
9.2.1	Post-application Dermal Exposure	36
9.2.2.	Post-application Inhalation Exposure	36
10.0	References	37
Appendix A.  Toxicology Profile and Executive Summaries	38
Appendix B.	Physical/Chemical Properties.	60
Appendix C.  Review of Human Research	60

1.0	Executive Summary

The Interregional Research Project Number 4 (IR-4) has submitted a petition requesting the establishment of permanent tolerances for residues of methoxyfenozide in or on dates;
caneberries (subgroup 13-07A); grain sorghum forage; grain sorghum stover; grain sorghum grain; sweet sorghum forage; sweet sorghum stover; sweet sorghum grain; sweet sorghum stalk; aspirated grain fractions (AGF), based on sorghum data; dried shelled peas and beans, except soybean (subgroup 6C), except blackeyed pea and southern pea; fresh herbs (subgroup 19A), except chives; and dried herbs (subgroup 19A), except chives.  Tolerances in the updated crop groups 8-10 and 11-10, and in the updated subgroups 13-07F and 13-07G were requested.  Tolerances in sugar apples, cherimoyas, atemoyas, custard apples, ilamas, soursops, and biribas were also requested, based on translation of avocado residues.  

Additionally, indirect or inadvertent tolerances in the rapeseed subgroup (20A) and the sunflower subgroup (20B) were requested.  The proposed new uses in dates, caneberries, sorghum and herbs are supported by magnitude of residue data generated by IR-4.  Other changes are supported by data previously reviewed by the Agency in 2009.  The requested changes for rapeseed and sunflower group are based on 2012 recommendations by EPA.  The petition proposes the deletion of the (expired) temporary tolerances in sorghum commodities, and their replacement with permanent tolerances in those commodities.  The tolerance in AGF would be increased from 2.0 to 120 ppm.  The tolerance of 0.5 ppm in dried shelled peas and beans, except soybean (subgroup 6C) was proposed at the Agency's request to better harmonize with existing Codex MRLs, with no changes in the existing use pattern for these commodities.  The existing tolerances in dried beans and dried peas would be deleted concurrently with the establishment of tolerances in subgroup 6C.  The tolerance in coriander leaves would be deleted concurrently with the establishment of the tolerance in subgroup 19A.  Finally, California is requesting a Section 18 for use of Intrepid 2F on dates/palm only.  The proposed use pattern for this Section 18 use is identical to that for the Section 3 IR-4 petition, with the same submitted residue data being used in support of both petitions.  

In developing this human health risk assessment, HED has examined the available hazard and exposure information regarding methoxyfenozide as it relates to its registered and requested uses.  The existing use on ornamentals was previously reassessed in accordance with current policies, based on the potential for residential handlers to use products in and around home gardens.  The toxicology database is considered complete for the purpose of characterizing the hazard associated with methoxyfenozide and for conducting a human health risk assessment.  

The main target organs in the rat and dog were the liver, thyroid and red blood cells (RBCs).  The most consistent findings across species and studies were decreased red blood cell parameters and increased liver, thyroid, adrenal and spleen weights.  Many of the available short-term or subchronic toxicity studies showed little or no toxicity.  Increases in thyroid and adrenal weights were observed in the rat chronic oral study.  Thyroid weights were also increased in the dog following chronic exposure, but no accompanying histopathology was observed.
 
Toxicological testing indicates that methoxyfenozide is not neurotoxic or immunotoxic; it has been categorized as "not likely" to be carcinogenic to humans.  There is no evidence of qualitative or quantitative susceptibility of the developing fetus or offspring, based on the developmental and reproductive toxicity study results.  Therefore, based on the completeness of the database, the lack of susceptibility, the lack of neurotoxicity and the conservative nature of the exposure assessment, HED has reduced the 10X Food Quality Protection Act (FQPA) Safety Factor to 1X.

Based on the submitted toxicology data and the current and proposed use patterns, HED selected endpoints for chronic dietary risk assessment, as well as for inhalation risk assessment for residential and occupational handlers.  Acute dietary risk was not evaluated because there were no toxic effects associated with a single dose, and therefore an appropriate endpoint was not identified.  There was no toxicity observed in the dermal toxicity study, and no concern for potential developmental effects; therefore, a dermal endpoint was not selected, and no dermal exposure and risk assessments were conducted (i.e., there is no hazard via the dermal route).  Furthermore, HED did not select an endpoint for incidental oral risk assessment, since the potential for post-application oral exposure to children resulting from the existing use of methoxyfenozide on ornamentals is extremely low.  Inhalation risks were assessed using the endpoint and dose from an oral study, with the assumption that inhalation toxicity would be equivalent to oral toxicity for the purpose of route-to-route extrapolation.  The endpoint selected for chronic dietary risk assessment was based on liver and thyroid effects observed in the chronic/carcinogenicity study in the rat; the blood effects seen in the dog study were considered co-critical.  For inhalation risk assessment, the endpoint selected was based on blood effects seen in a range-finding study in the dog.

HED used modeling to assess chronic dietary exposure to methoxyfenozide.  In combination with an extensive database of food consumption patterns for the U.S. population and population subgroups, this modeling used conservative upper-bound assumptions regarding residues of methoxyfenozide and its breakdown products in food and drinking water.  Specifically, the dietary assessment included tolerance-level residues from the existing and proposed uses, the assumption of 100% crop treated (CT) for all crops, and drinking water residues derived from modeling the maximum application rate in vulnerable areas.  The highest potential drinking water exposure is from ground water sources.  The chronic dietary exposure and risk estimates are below HED's level of concern (LOC) of 100% of the chronic population adjusted dose (cPAD) for the general U.S. population and all population subgroups, including those of infants and children.  The highest exposed population subgroup was children 1-2 years old, with a dietary risk estimate of 84% cPAD; all other population subgroups had lower risk estimates, including the general U.S. population at 31% cPAD.

Residential exposures are those that may occur as a result of activities in and around the home, schools and recreational areas.  Prior to 2012, a residential exposure assessment was not performed in conjunction with registration of the use of methoxyfenozide on ornamentals.  Since then an inhalation endpoint was selected and the OPP HED Residential SOPs were finalized and approved for risk assessment purposes.  Therefore, in the most recent 2012 new use risk assessment, HED assessed potential inhalation exposure for residential handlers treating ornamentals in and around home gardens (D388978, M. Collantes et al, 05/23/2012).  The resulting risk estimates are margins of exposure (MOEs) ranging from 76,000 to more than 3 million, which are not of concern.

In accordance with the FQPA, in evaluating human health risks from exposure to pesticides, HED aggregates exposure from various routes, i.e., residential exposure is added to dietary exposure from food and drinking water.  The residential handler exposure resulting from applying methoxyfenozide to ornamentals using a backpack sprayer was combined with the chronic dietary exposure from the most highly exposed adult population subgroup (general US adult population) to determine aggregate exposure and risk.  The calculated exposure resulted in an aggregate MOE of 530; this risk estimate is not of concern, since it is significantly higher than the LOC of 100.

An occupational exposure assessment was also performed for handler and post-application activities, based on standard assumptions with respect to body weight and area treated, in accordance with HED's standard procedures.  There were no chemical specific data available to assess handlers' inhalation exposure, so HED relied on surrogate data generated by various task forces.  The resulting inhalation risk estimates were MOEs ranging from 20,000 to more than 3 million and were not of concern.  A quantitative post-application exposure assessment was not completed due to the lack of dermal toxicity, and because the handlers' MOEs are expected to be protective of post-application exposure via the inhalation route.

The risk assessment is based, in part, on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical.  These studies are compliant with applicable ethical requirements (refer to Appendix C).

2.0	HED Recommendations

HED recommends in favor of the proposed registration of the new uses of methoxyfenozide on dates, sorghum, caneberries (subgroup 13-07A), and herbs (subgroup 19A) except chives, as well as updates to multiple existing tolerances supported by the existing database (with no changes in the use pattern), and establishment of the associated permanent tolerances as summarized in Table 2.2.3.

2.1	Data Deficiencies/Conditions of Registration

None

2.2	Tolerance Considerations
2.2.1	Enforcement Analytical Method

The FDA multiresidue methods are not suitable for analysis of methoxyfenozide or its regulated metabolites.  However, adequate single methods are available for enforcing the current tolerances for methoxyfenozide in primary crops and animal commodities.  Depending on the plant commodity, the limits of quantitation (LOQs) for methoxyfenozide in primary crop commodities are 0.010-0.050 ppm.  The tolerance enforcement methods include use of high performance liquid chromatography (HPLC), with either tandem mass spectrometric detection (LC/MS/MS), or ultraviolet detection (HPLC/UV).  

2.2.2	International Harmonization

Codex has not established MRLs in any of the proposed new uses.  As such, there are no harmonization issues associated with Codex for the proposed new uses in the current action.  Canada's PMRA has established MRLs in fresh Chinese chive leaves and fresh chive leaves at 5 mg/kg.  There are no Canadian MRLs in dates, caneberries or sorghum commodities.  However, for basil and caneberries, this action is being performed as a joint review with Canada's PMRA, and the recommended tolerances have been harmonized with the recommended PMRA tolerances as appropriate.  HED's recommended tolerances for the new uses were determined using the Organization for Economic Cooperation and Development (OECD) tolerance calculation procedures.  

Codex has established MRLs in grapes at 1 mg/kg, in strawberries and pome fruits at 2 mg/kg, in avocadoes at 0.7 mg/kg, and in papayas at 1 mg/kg.  

The recommended tolerance of 2.0 ppm in the updated pome fruits group (11-10), increased from the current tolerance of 1.5 ppm in group 11, would be harmonized with the Codex MRL.  It is noted that this recommended revised tolerance in pome fruit will not be harmonized with the existing PMRA tolerance of 1.5 ppm. HED has made PMRA aware of this issue, but has determined that Codex harmonization is beneficial at this time. 

The recommended tolerance of 1.0 ppm in small vine-climbing fruit, except fuzzy kiwifruit (subgroup 13-07F), translated from grape data, would be harmonized with the Codex MRL in grapes.  The recommended tolerance of 2.0 ppm in low-growing berries (subgroup 13-07G), translated from strawberry data, and increased from the current tolerance of 1.5 ppm in strawberries, would be harmonized with the Codex MRL in strawberries.  

The recommended tolerance of 0.50 ppm in dried shelled peas and beans, except soybeans (subgroup 6C) was proposed at the Agency's request to better harmonize with the existing Codex MRL of 0.5 mg/kg in dried beans.  This tolerance would replace the current tolerances of 0.24 ppm in dried beans, and 2.5 ppm in dried peas, which would both be removed.  

The recommended tolerance of 0.60 ppm in various tropical tree fruits is translated from avocado data, where there is an existing USEPA tolerance of 0.6 ppm.  There is also an existing USEPA tolerance of 0.6 ppm on papaya.  With the existing avocado and papaya tolerances not being harmonized, these new tropical tree fruit tolerances would also not be harmonized with the Codex MRLs as well.  During registration review, to the extent possible USEPA will consider opportunities for harmonizing tropical tree fruit tolerances with Codex.    

2.2.3	Recommended Tolerances

TABLE 2.2.3.	Tolerance Summary for Methoxyfenozide.  
                                   Commodity
                                Tolerance (ppm)
                   Correct Commodity Definition.  Rationale
                                       
                                   Existing 
                                   Proposed
                                 Recommended 
                                       
                                 180.544[a][1]
Herb subgroup 19A, fresh, except chives
                                     None
                                      70
                                      400
Herb subgroup 19A, except chive.  Based on submitted dried basil field trial data.  
Herb subgroup 19A, dried, except chives
                                     None
                                      400
                                       

Date
                                     None
                                      7.0
                                      8.0
Based on submitted crop field trial data.  
Caneberry subgroup 13-07A
                                     None
                                      6.0
                                      6.0

Sorghum, grain, forage
                                     None
                                      9.0
                                      15

Sorghum, grain, stover
                                     None
                                      15
                                      20

Sorghum, grain, grain
                                     None
                                      4.0
                                      6.0

Sorghum, sweet, forage
                                     None
                                      9.0
                                      15

Sorghum, sweet, stover
                                     None
                                      15
                                      20

Sorghum, sweet, grain
                                     None
                                      4.0
                                      6.0

Sorghum, sweet, stalk
                                     None
                                      9.0
                                      15

Grain, aspirated grain fractions
                                      2.0
                                      80
                                      120
Based on sorghum field trial and processing study data.  
Pea and bean, dried shelled, except soybean, subgroup 6C, except pea, blackeyed, seed and pea, southern, seed
                                     None
                                      0.5
                                     0.50
To harmonize with Codex MRLs.  
Fruit, small, vine climbing, except fuzzy kiwifruit, subgroup 13-07F
                                     None
                                      1.0
                                      1.0
Translated from grape data.  
Berry, low growing, subgroup 13-07G, except cranberry
                                     None
                                      1.5
                                      2.0
Translated from strawberry data, and raised to harmonize with Codex MRL in strawberries.  
Fruit, pome, group 11-10
                                     None
                                      1.5
                                      2.0
Update of group 11, and raised to harmonize with Codex MRL in apples.  
Vegetable, fruiting, group 8-10
                                     None
                                      2.0
                                      2.0
Update of group 8.  
Sugar apple
                                     None
                                      0.6
                                     0.60
Translated from avocado data.  
Cherimoya
                                     None
                                      0.6
                                     0.60

Atemoya
                                     None
                                      0.6
                                     0.60

Custard apple
                                     None
                                      0.6
                                     0.60

llama
                                     None
                                      0.6
                                     0.60

Soursop
                                     None
                                      0.6
                                     0.60

Biriba
                                     None
                                      0.6
                                     0.60

Pea, blackeyed, seed
                                      4.0
                                      4.0
                                      4.0
Keep as exceptions to subgroup 6C.  
Pea, southern, seed
                                      4.0
                                      4.0
                                      4.0

Coriander, leaves
                                      30
                                    Remove
                                    Remove
Covered under subgroup 19A tolerance.  
Grape
                                      1.0
                                    Remove
                                    Remove
Covered under subgroup 13-07F tolerance.  
Strawberry
                                      1.5
                                    Remove
                                    Remove
Covered under subgroup 13-07G tolerance.  
Okra
                                      2.0
                                     None
                                    Remove
Covered under group 8-10 tolerance.  
Pea, dry seed
                                      2.5
                                    Remove
                                    Remove
Covered under subgroup 6C tolerance.  
Bean, dry, seed
                                     0.24
                                    Remove
                                    Remove

                                  180.544[b]
Sorghum, grain, forage
                                      30
                                     None
                                    Remove
Expired time-limited tolerances.  
Sorghum, grain, stover
                                      60
                                     None
                                    Remove

Sorghum, grain, grain
                                     0.05
                                     None
                                    Remove

                                 180.544[d][2]
Herb and spice, group 19, except coriander, leaves
                                      4.5
                                     None
                                    Remove
Replaced by primary tolerance in subgroup 19A, except chive, and rotational tolerances in chive and subgroup 19B.  
Spice subgroup 19B
                                     None
                                     None
                                      4.5
These replace the rotational crop tolerance in group 19, except coriander leaves.  
Chive
                                     None
                                     None
                                      4.5

Rapeseed subgroup 20A
                                     None
                                      1.0
                                      1.0
Based on existing rotational crop data, and HED's previous recommendation.  
Sunflower subgroup 20B
                                     None
                                      1.0
                                      1.0


2.2.4	Revisions to Petitioned-For Tolerances

In fresh herbs, subgroup 19A (except chives), the petitioner proposed a tolerance of 70 ppm, based on the Organization of Economic Development and Cooperation's (OECD's) tolerance calculation procedure.  However, the petitioner entered all 10 sample residues into the MRL calculator.  When the average residues from each of the 5 basil field trials were entered, as the OECD guidance stipulates, the resulting recommended tolerance would be 80 ppm.  However, USEPA has determined that setting separate subgroup 19A tolerances for fresh and dried commodities is not feasible from a regulatory perspective.  Therefore, HED recommends setting the entire subgroup 19A tolerance, except chives, for both fresh and dried commodities at the higher 400 ppm level.  This 400 ppm level is derived using the submitted dried basil field trial data in the OECD calculation procedure.  

The primary crop tolerance in coriander leaves, along with the rotational crop tolerance in herbs and spices (group 19), except coriander leaves, would be removed concurrently with the establishment of the primary crop tolerance in subgroup 19A, except chives.  Although not proposed in the petition, rotational crop tolerances would necessarily be established in chives and in spices (subgroup 19B) upon establishment of the primary crop tolerance in subgroup 19A, except chives.  
   

In dates, the petitioner proposed a tolerance of 7.0 ppm, based on 4 date field trials and OECD's tolerance calculation procedure.  However, HED determined that only 3 of the trials were truly independent.  The 4 sample residues from the 2 trials deemed to be non-independent were averaged together as one input into the MRL calculator.  In addition, the total application rate at one of the other trials was only half the proposed maximum seasonal use rate, a difference of >25%.  Therefore, the residue values from this trial were doubled, per OECD's preliminary guidance on proportionality of sample residues to application rate [EPA Chemistry Science Advisory Council (ChemSAC), minutes, 3/28/2012].  When the average of these residues, along with the average residues from each of the other 2 field trials were entered into the MRL calculator, the resulting recommended tolerance was 8.0 ppm.  

In sorghum commodities, the petitioner proposed tolerances of 9.0, 15 and 4.0 ppm in the forage, stover and grain, respectively, of both grain and sweet sorghum, and 9.0 ppm in sweet sorghum stalks, based on OECD's tolerance calculation procedure.  A tolerance of 80 ppm in sorghum AGF was proposed, based on the sorghum processing study.  However, with the use of the correction for proportionality, the resulting recommended tolerances were 15, 20 and 6.0 ppm in the forage, stover and grain, respectively, of both grain and sweet sorghum, and 15 ppm in sweet sorghum stalks.  The increase in the proposed tolerance of 80 to 120 ppm for residues in AGF was also based on the adjustment for proportionality.  Although not proposed by the registrant, HED recommends that existing time-limited sorghum tolerances (established under 180.544[b]), be removed for forage, stover, and grain, as these tolerances have now expired.

Instead of the proposed tolerances in the various tropical tree fruits (0.6 ppm), HED recommends establishing the tolerances at 0.60 ppm, in order to avoid the situation where a field sample containing residues significantly above the tolerance (0.64 ppm, for example) would be considered non-violative.  For the same reason, HED recommends that the proposed tolerance of 0.5 ppm in subgroup 6C (except blackeyed and southern peas) be revised to 0.50 ppm.  

As previously discussed, HED recommends the tolerance of 2.0 ppm in the updated pome fruits group (11-10), increased from the proposed tolerance of 1.5 ppm, in order to be harmonized with the Codex MRL.  The recommended tolerance of 2.0 ppm in low-growing berries (subgroup 13-07G), translated from strawberry data, was increased from the proposed tolerance of 1.5 ppm, in order to be harmonized with the Codex MRL in strawberries.
2.3	Label Recommendations From Residue Review

Methoxyfenozide is a candidate for a 4-hour restricted entry interval (REI) which appears on the proposed supplemental and master labels.  However, the Registration Division should confirm that methoxyfenozide is a reduced risk chemical and that the correct REI is on the final registered label.

3.0	Introduction

3.1	Chemical Identity

TABLE 3.1	Methoxyfenozide Nomenclature.  
Chemical structure
                                       
Common name
Methoxyfenozide
Company experimental name
RH-2485
Molecular formula
C22H28N2O3
Molecular weight
368.47
IUPAC name
N-tert-butyl-N′-(3-methoxy-o-toluoyl)-3,5-xylohydrazide
CAS name
3-methoxy-2-methylbenzoic acid 2-(3,5-dimethylbenzoyl)-2-(1,1-dimethylethyl)hydrazide
CAS registry number
161050-58-4
End-use product (EP)
2 lb ai/gal F (Intrepid 2F, EPA Registration #62719-442)


3.2	Physical/Chemical Characteristics

THE INFORMATION REGARDING Physical chemical characteristics of methoxyfenozide does not indicate that there are any special concerns in terms of bioaccumulation, exposure or other risk assessment considerations. A table of physical and chemical properties for methoxyfenozide is included in Appendix B.

Methoxyfenozide has a low dermal absorption factor.  Dermal absorption is the process by which chemicals are transported from the outer surface of the skin into both the inner layers of the skin and into the body.  The dermal absorption factor is a numerical estimate of the percentage of the topical external dose that traverses the skin layers to the systemic circulation (e.g. the percentage of the topical external dose that is bioavailable). An in vivo dermal absorption study on an 80% wettable powder (WP) formulation of methoxyfenozide was conducted in the rat.  Cumulative absorption of approximately 2% of the applied dermal dose was observed after a 10 or 24 hour dermal exposure duration.  Consistent with the low level of absorption, a 28-day dermal study in the rat showed no toxicity up to the limit dose (1000 mg/kg/day).   Furthermore, methoxyfenozide has a large octanol-water partition coefficient (Kow) of 10[3.72] which further supports that methoxyfenozide is not easily absorbed by the skin and thus would result in lower dermal exposure.

Although methoxyfenozide is very persistent (t1/2 = 1 to 3 years in soil and water), it is not significantly volatile, and has a vapor pressure of 1.0 x 10[-][7] mm Hg at 25˚ C.  Therefore, significant inhalation exposure to methoxyfenozide is not expected.  

3.3	Pesticide Use Pattern

Methoxyfenozide is currently registered for use on ornamentals and a wide variety of agricultural crops.  

Dow AgroSciences LLC is requesting new proposed uses of the insecticide methoxyfenozide be added to the Intrepid 2F (Reg. No. 62719-442) label.  The proposed Section 3 registration includes use on herbs (subgroup 19A) except chives, dates, sorghum and caneberries (subgroup 13-07A).  In addition, California is requesting a Section 18 for use of Intrepid 2F on dates/palm only.  Intrepid 2F is formulated as a flowable concentrate containing 22.6% active ingredient (ai) or 2 lb ai per gallon.  Intrepid 2F may be applied by air, groundboom, airblast and hand held equipment.   The master label specifies that the product is not to be applied by chemigation unless specified in crop-specific directions on the label or supplemental labeling.  Therefore, since the supplemental labels did not specify use of chemigation for the proposed crops, it was not assessed as a potential method of application.

The Personal Protective Equipment (PPE) statement on the proposed label requires applicators and other handlers to wear long-sleeved shirt and long pants, socks, shoes, and chemical-resistant gloves.  

Table 3.3 provides a summary of the proposed uses. 

TABLE 3.3	Summary of Directions for Use of Methoxyfenozide.  
                          Application Type; Equipment
                                   Use Rate
                                   (lb ai/A)
                             Max. Uses Per Season
                            Max. Seasonal Use Rate
                                 (lb ai/A)[1]
                                 PHI[1] (Days)
              Use Directions, Application Timing, and Limitations
                      Herbs (Subgroup 19A), Except Chives
                           Foliar; Ground and Aerial
                                     0.12
                                     NS[2]
                                      1.0
                                       1
Minimum RTI[3] of 10 days.  Ground application:  Apply in a minimum of 10 GPA[4] to young crop or small plants.  Apply in a minimum of 20 GPA to densely foliated or difficult-to-cover crops to ensure thorough coverage.  Aerial application:  Apply in a minimum of 10 GPA.  
                                     Dates
                               Ground (Airblast)
                                     0.31
                                      NS
                                      1.0
                                       7
Begin applications before eggs hatch. Minimum RTI of 10 days.  Alternate or intersperse with other insecticides. Apply in a minimum of 100 GPA.  
                                    Sorghum
                           Foliar; Ground and Aerial
                                     0.16
                                      NS
                                     0.75
                                   3, 21[5]
Apply at first sign of egg hatch or when infestations reach threshold levels.  Ground application:  Apply in a minimum of 15 GPA.  Aerial application:  Apply in a minimum of 10GPA.  
                         Caneberries (Subgroup 13-07A)
                           Foliar; Ground and Aerial
                                     0.25
                                       3
                                     0.75
                                       3
Apply at initiation of egg-laying.  Make second application at 100% petal fall.  A third application may be required under high pest pressure.  Minimum RTI of 7 days.  Ground application:  Apply in a minimum of 30 GPA.  Aerial:  Apply in a minimum of 10 GPA.  
1. PHI = Pre-Harvest Interval.  
2. NS = Not Specified.  
3. RTI = Re-Treatment Interval.  
4. GPA = Gallons Per Acre.  
5. Minimum PHI of 3 days for forage and sweet sorghum stalks, and 21 days for grain and stover.  

3.4	Anticipated Exposure Pathways

As a result of the registered and proposed uses of the insecticide methoxyfenozide, humans may be exposed through food and drinking water, since the chemical may be applied directly to growing crops and may reach surface and ground water sources of drinking water.  In an occupational setting, applicators may be exposed while handling the pesticide prior to application (i.e., mixing/loading), as well as during application.  There is also potential for post-application exposure for workers re-entering treated fields. 

Since methoxyfenozide is also registered for use on ornamentals there is likely to be exposure in residential and non-occupational settings as well.  While the product does not appear to be intended for homeowner use, there is the potential for homeowners to purchase and apply the product to their own ornamentals.  Although there is also potential for dermal exposure, there is no expectation of dermal risk, based on the lack of dermal toxicity for methoxyfenozide.    Furthermore, the potential for post-application oral exposure to children is not expected since the extent to which young children engage in activities associated with areas where residential ornamentals are grown or use these areas for prolonged periods of play is low.  
This risk assessment considers all of the relevant exposure pathways, combining them as appropriate, to estimate overall exposure and risk. 

3.5	Consideration of Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Low-Income Populations," (http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf.  As a part of every pesticide risk assessment, OPP considers a large variety of consumer subgroups according to well-established procedures.  In line with OPP policy, HED estimates risks to population subgroups from pesticide exposures that are based on patterns of that subgroup's food and water consumption, and activities in and around the home that involve pesticide use in a residential setting.  Extensive data on food consumption patterns are compiled by the U.S. Department of Agriculture under the National Health and Nutrition Examination Survey, What We Eat in America, (NHANES/WWEIA).  These food consumption patterns are used in pesticide risk assessments for all registered food uses of a pesticide.  These data are analyzed and categorized by subgroups based on age, season of the year, ethnic group, and region of the country.  Additionally, OPP is able to assess dietary exposure to smaller, specialized subgroups and exposure assessments are performed when conditions or circumstances warrant.  Whenever appropriate, non-dietary exposures based on home use of pesticide products and associated risks for adult applicators and for children, youths, and adults entering or playing on treated areas post-application are evaluated.  Further considerations are currently in development as OPP has committed resources and expertise to the development of specialized software and models that consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups.

4.0	Hazard Characterization and Dose-Response Assessment

4.1	Toxicology Studies Available for Analysis

The toxicological database is considered complete for methoxyfenozide.  The following studies,  which utilize exposure routes (oral and dermal) consistent with potential human exposure scenarios, have been submitted:  primary acute toxicity, irritation and dermal sensitization; subchronic oral toxicity in the rat, mouse and dog; rat 28-day dermal toxicity; rat chronic oral toxicity/carcinogenicity; dog chronic oral toxicity; mouse oral carcinogenicity;  rat and rabbit oral  toxicity; rat oral two-generation reproductive toxicity; genotoxicity battery; rat acute and subchronic neurotoxicity; rat general metabolism; rat dermal penetration (on formulation); and rat immunotoxicity.  Although a 28-day inhalation toxicity study has not been submitted, HED has determined that this study is not needed (i.e., the study has been waived) for methoxyfenozide, based on a weight of evidence (WOE) approach that considered all of the available hazard and exposure information, including the use of a conservative oral point of departure (POD) that results in MOEs ranging from 20,000 to 3,100,000 for risk via the inhalation route due to residential and occupational exposures (TXR #0053782, 4/17/12).  

4.2	Absorption, Distribution, Metabolism, & Elimination (ADME)

In the rat, [14]C-radiolabeled methoxyfenozide was rapidly absorbed following gavage administration, with maximum peak plasma concentrations observed within 15 minutes of dosing.  Peak plasma concentrations at 10 mg/kg ranged from 0.70 to 1.09 ppm in males and 0.5 to 0.59 ppm in females, depending on the ring location of the radiolabel; at 1000 mg/kg, peak levels were 26.11-35.52 ppm in males and 21.92 to 29.74 ppm in females.   Plasma elimination was biphasic, with an α-phase T1/2 of 0.2 to 0.6 hr and a β-phase T1/2 of 15.2-35.6 hr and showed some variation with radiolabel location.  The total plasma elimination rate was longer for the high dose compared to the low dose animals, suggesting metabolic pathway saturation, and the effect was more prominent in female rats.  Radioactivity was extensively distributed among tissues, with the highest concentrations at Cmax (0.25 hr) observed in the intestinal tract, stomach, liver and residual carcass.  Enterohepatic circulation was observed.  Methoxyfenozide did not show a potential for bioaccumulation:  by 5 days' post-treatment, the highest levels were observed in the liver and carcass, but tissue radioactivity in all tissues was insignificant by that time.  Excretion of radiolabel was essentially complete by 48 hrs postdosing.  Based on the minimal level of radioactivity in tissues at 72 hours, absorption was estimated to be at least 62 to 70% of the administered dose (biliary plus urinary excretion).  The major route of excretion was in the feces (86-97% of the administered dose), with 5-13% of the dose excreted in the urine.  Significant dose- or sex-dependent differences in metabolic disposition were not observed.

Methoxyfenozide was extensively metabolized.  The major routes of metabolism involved O - demethylation and oxidative hydroxylation of the A-ring phenyl and/or B-ring methyl groups, followed by glucuronic acid or sulfate conjugation.  In addition to the parent compound, seven major metabolites were identified in excreta.  These included RH-131,157, RH-141,581 and RH-117,236, metabolites also identified in residues in crops or livestock.  Up to 25 metabolites were isolated from urine, but the majority represented <1-2% of the radioactive dose.  Up to 16 metabolites were identified in the feces, including the parent compound, with only six containing >=5% of the administered radiolabel.  The major fecal metabolites in all groups were products of Phase I O-demethylation and oxidative hydroxylation on the A-ring and, to a lesser extent, the B-ring.  Levels of excreted parent compound in the feces were greater in animals receiving 1000 mg/kg test material (30 to 39% of dose) when compared to the 10 mg/kg groups (14-26% of dose), consistent with saturation of absorption.  In the bile, up to 24 metabolites were detected, with the primary metabolite (13-18% of dose) being derived by glucuronide conjugation at the 0-demethylated alpha ring.  
4.2.1	Dermal Absorption

An in vivo dermal absorption study on an 80% wettable powder (WP) formulation of methoxyfenozide was conducted in the rat.  Cumulative absorption of approximately 2% of the applied dermal dose was observed after 10 or 24 hours of dermal exposure.  Consistent with this low level of absorption, a 28-day dermal study in the rat showed no toxicity up to the limit dose (1000 mg/kg/day).

4.3	Toxicological Effects

Methoxyfenozide is a diacylhydrazine insecticide active against lepidopterous insects (moths and butterflies) by competitively binding to receptors of the molting hormone in larvae.  Many of the available short-term or subchronic toxicity studies on methoxyfenozide showed little or no toxicity.  The main target organs were the liver, thyroid and red blood cells.  In the rat metabolism study, liver contained 2-9% of the administered radioactivity at Cmax, but levels decreased and bioaccumulation was not observed.  Levels in the blood were negligible.  The effects of methoxyfenozide on the blood in mammals (methemoglobinemia, decreased red blood cell parameters, Heinz body formation) are consistent with those of other hydrazine compounds.

Hematologic parameters in the rat and dog were affected by exposure to methoxyfenozide.  Mild anemia (decreases in RBC count, hematocrit and hemoglobin) was observed in both species following chronic dietary exposure, along with methemoglobinemia and RBC structural abnormalities.  Increased platelets were also observed.  An increase in the cellularity of rib and sternum bone marrow, along with macrophage pigmentation in the liver and spleen, were reported in the dog.  No significant hematological changes were seen in the dog or rat subchronic studies, or the rat two week range-finding studies; however, hematological effects were observed in the dog two week range-finding study, along with increased spleen weight.  The data suggest that a compensatory mechanism for the RBC effects may occur over time, based on the effects observed at two weeks in the dog range-finding studies that were not observed in the subchronic study, and on more pronounced changes in hematological parameters at Week 14 in the rat and dog chronic studies than were observed at evaluations conducted at later times in those studies.  No hematological effects were reported in the mouse.
  
Increased liver weight and periportal hypertrophy were observed in the rat and dog.  These findings were observed in the rat following two-week, subchronic or chronic dietary exposure, and in the dietary reproductive toxicity study, and in the dog following chronic exposure.  In the rat two-week study, increased adrenal gland weight and minimal hypertrophy of the zone fasciculata, and increased thyroid follicular cell hypertrophy/hyperplasia were also observed; however, these findings were not seen with subchronic exposure.  Thyroid hypertrophy and altered colloid and increased adrenal weights were observed in the rat chronic oral study, and the incidence and severity of chronic progressive glomerulonephropathy was increased.  Thyroid weights were increased in the dog following chronic exposure, but there was no accompanying histopathology.

In the mouse, effects were limited to decreased body weights and weight gain in the subchronic study; however, no effects were seen in the carcinogenicity study at dietary concentrations exceeding the limit dose.  No body weight effects were observed in the rat or dog.

Acute and subchronic oral neurotoxicity studies in the rat did not show evidence of potential neurotoxicity.  In the acute study, decreased hindlimb grip strength on Day 0 was reported in males.  This finding was only observed at the limit dose in males and was not observed in the subchronic neurotoxicity study and was therefore not considered evidence of neurotoxicity.  No clinical signs of toxicity or neurohistopathology were observed in other guideline studies.

No maternal or developmental effects were observed in either the rat or rabbit oral developmental toxicity studies.  In the rat two-generation reproductive toxicity study, parental effects were limited to increased liver weight and microscopic periportal hypertrophy.  No offspring or reproductive toxicity was observed.  In a 28-day dietary immunotoxicity study in the rat, no immunotoxicity was observed.  The only observed effect was increased liver weight.

Dermal effects were not observed in the rat following a 28-day exposure period (5 exposure days per week for a total of 20 exposures).  This finding is consistent with the relatively low dermal absorption of 2% of the applied dose, observed in an in vivo dermal absorption study in rats treated with an 80% WP formulation product.

There was no evidence of carcinogenicity in the rat dietary 24-month chronic toxicity/carcinogenicity study or the mouse dietary 18-month carcinogenicity study.  No mutagenic or clastogenic potential was observed in the battery of genotoxicity studies on methoxyfenozide.  Based on these findings, methoxyfenozide is classified as "not likely to be carcinogenic to humans" (2005 Agency revised carcinogenicity assessment guidelines).

4.4	Safety Factor for Infants and Children (FQPA Safety Factor)

The required 10X FQPA safety factor for methoxyfenozide was reduced to 1X, based on the following considerations: 1) the toxicity database for methoxyfenozide is complete, including studies addressing potential pre- and post-natal susceptibility; 2) there is no evidence that methoxyfenozide is neurotoxic, and a developmental neurotoxicity study is not required; 3) there is no residual uncertainty, and no evidence of  increased quantitative or qualitative susceptibility in the developing or young animal; and 4) the dietary exposure assessments do not underestimate potential exposure from food and drinking water, and the use pattern indicates a low potential for residential exposure.

 4.4.1	Completeness of the Toxicology Database

The database is considered complete with respect to evaluation of potential susceptibility/sensitivity of infants and children.  Acceptable developmental toxicity studies in two species (rat and rabbit) and a rat two-generation reproduction study have been submitted, as well as rat acute and subchronic neurotoxicity and immunotoxicity studies.  A developmental neurotoxicity study is not required, based on the lack of evidence of neurotoxicity in the adult animal and lack of increased sensitivity/susceptibility in the developing or young animal.
4.4.2	Evidence of Neurotoxicity

The available toxicity data, which include acute and subchronic neurotoxicity studies in the rat, do not demonstrate neurotoxic potential.  A decrease in hindlimb grip strength, observed in male rats on Day 0 of the acute neurotoxicity study, was not considered to be evidence of neurotoxicity because it was an isolated finding in males, not observed in females and seen only at the limit dose of 2000 mg/kg.  Additionally, no evidence of neurotoxicity was observed in the rat subchronic neurotoxicity or other studies.  A developmental neurotoxicity study is therefore not required.
4.4.3	Evidence of Sensitivity/Susceptibility in the Developing or Young Animal

There was no evidence of increased qualitative or quantitative susceptibility in the developing or young animal.  No developmental toxicity was observed in either the rat or rabbit developmental toxicity studies, and there was no evidence of offspring or reproductive toxicity in the rat two-generation reproductive toxicity study.  Dosing in all studies achieved the limit dose (>=1000 mg/kg/day).
 
4.4.4	Residual Uncertainty in the Exposure Database

There is no residual uncertainty with respect to the exposure assessments conducted for methoxyfenozide.  The dietary exposure estimates incorporate conservative estimates of all residues of concern from the food exposure pathways.  There remains an outstanding data requirement for monitoring of surface water and sediment in a representative sample of high use areas in proximity to surface water.  Thus, the Environmental Fate and Effects Division (EFED) continues to have concerns about the persistence of methoxyfenozide and potential uncertainties regarding the long-term drinking water exposure associated with the use of methoxyfenozide, and has used a highly conservative approach in deriving modeled drinking water values for the purpose of risk assessment.  The aggregate assessment including exposure from the proposed use on ornamentals also used high-end default assumptions; there is a very low potential for children's exposure to residues resulting from treatment of ornamentals.

4.5	Toxicity Endpoint and Point of Departure Selections
4.5.1	Dose-Response Assessment

A toxicity profile table, endpoint selection rationales and detailed summaries of the toxicity studies considered in the selection of toxicity endpoints for exposure assessment are provided in Appendix A of this document.

For acute dietary exposure assessment, the rat acute oral neurotoxicity study was considered for selection of a dose and endpoint.  This study was not selected because the only finding was decreased grip strength in males on Day 0 (day of dosing) at the limit dose of 2000 mg/kg; no toxicity was observed at 1000 mg/kg in males or in females up to 2000 mg/kg.  The developmental oral toxicity studies in the rat and rabbit were also considered but not selected because no maternal or developmental toxicity was observed at doses up to the limit dose (1000 mg/kg/day).  There were also no clinical effects on the initial day of dosing in any other oral toxicity study.

For selection of a chronic dietary exposure assessment dose and endpoint, the dietary rat chronic toxicity/carcinogenicity, dog chronic (1 year) and rat reproductive toxicity studies were considered.  The mouse carcinogenicity study showed no effects at dietary concentrations administering methoxyfenozide slightly above the limit dose of 1000 mg/kg/day.  Increased liver weight at doses exceeding the limit dose was the only effect observed in parental animals in the rat reproductive toxicity study, and there were no offspring or reproductive effects.  The rat chronic toxicity/carcinogenicity study with a NOAEL of 10.2 mg/kg/day was selected for determination of the cRfD.  The chronic dog study was selected as the co-critical study because these were the most sensitive studies available and the similar NOAELs (10.2 and 9.8 mg/kg/day for the rat and dog, respectively) yielded the same cRfD of 0.10 mg/kg/day.  Hematological effects were observed in both studies at the LOAELs of 106 mg/kg/day in the dog and 411 mg/kg/day in the rat.  In the rat, periportal liver hypertrophy, thyroid hypertrophy and altered colloid and increased adrenal weight were also observed at the LOAEL.  The selected dose and endpoint is protective for potential developmental effects and toxicity to the young, based on lack of developmental effects (rat and rabbit developmental studies) or toxicity to offspring (rat reproductive toxicity study) and lack of evidence of neurotoxicity.   It is also protective of hematological and other effects observed in the dog and rat two-week range-finding studies (see below).  The NOAELs/LOAELs from all other available studies were observed at higher dose levels.  

Endpoints were not selected for incidental oral exposure because, based on current and proposed use patterns which specify use on ornamentals and not turf, there are no residential uses for methoxyfenozide where significant post-application exposure to young children is anticipated.
For dermal exposure (all durations, residential and occupational exposure), an endpoint was not selected.  The rat 28-day dermal toxicity study demonstrated no toxicity up to the limit dose (1000 mg/kg/day).  Several oral toxicity studies with observed LOAELs were also considered, including the subchronic dietary studies in the rat, mouse and dog, two-week range-finding studies in the rat and dog, and the rat reproductive toxicity study.  However, the effects observed in the oral studies, which included liver hypertrophy and hematologic parameters, were evaluated in the 28-day dermal study but showed no effect of treatment.  The developmental oral toxicity studies in the rat and rabbit showed no maternal or developmental toxicity and the rat subchronic dietary neurotoxicity showed no toxicity at doses up to the limit dose (1000 mg/kg/day).  The rat 28-day dermal toxicity study was therefore considered protective of sensitive populations, including potential developmental effects.  

In past risk assessments, HED did not quantitatively assess inhalation exposure and risk, and there is no route-specific repeated-dose inhalation toxicity study available for this purpose; however, in accordance with the current policy for conducting inhalation assessments, the risk assessment team selected a dose and endpoint from the available oral studies.  The studies considered included two-week oral range-finding studies in the rat and dog, subchronic oral toxicity studies in the rat and mouse, and the reproductive toxicity study in the rat.  The subchronic oral dog study, rat and rabbit oral developmental toxicity and the rat 90-day neurotoxicity and immunotoxicity studies were not considered because no toxicity was observed.  

The two week dietary study in the dog was selected for both short- and intermediate-term inhalation exposure because it provided the most sensitive dose and endpoint available (NOAEL = 16.8 mg/kg/day, based on hematological effects at the LOAEL of 90.8 mg/kg/day) and was of an appropriate duration.  The NOAEL and LOAEL were selected from the highest individual animal NOAEL and lowest LOAEL because only two animals/sex/dose were tested.  Effects observed at the LOAEL included mild anemia, methemoglobinemia and abnormal RBC structure, and were consistently observed in individual animals.  Although these effects were not identified in the dog 90-day dietary study at dose levels up to about 200 mg/kg/day, mild anemia and methemoglobinemia were observed at Week 14 and later in the chronic dog study at doses of 106 mg/kg/day.  Additionally, in the rat two week range-finding study there were effects observed on the thyroid and adrenal gland at a comparable dose (69.3 mg/kg/day), with a NOAEL of 17 mg/kg/day (effects not observed in the subchronic rat study).  These findings were not seen in the subchronic studies, suggesting a compensatory mechanism for the toxicity of methoxyfenozide with prolonged exposure.  This dose and endpoint are therefore considered to be very conservative, but protective of all populations that may be exposed.  In light of the conservative endpoint, low acute inhalation toxicity of methoxyfenozide, low vapor pressure and low application rates for current use patterns, this oral study is considered to be protective for potential inhalation toxicity.
4.5.2	Recommendation for Combining Routes of Exposures for Risk Assessment

Dermal exposure was not assessed due to a lack of toxicity via the dermal route.  Since adults were assessed for potential inhalation exposure while applying methoxyfenozide to ornamentals, this exposure should be combined with background levels in food and water to determine aggregate exposure.  For children's residential exposure, oral post-application exposure was not assessed; only exposure from background levels of food and drinking water were assessed.  For occupational workers, only inhalation exposure and risk were assessed.
4.5.3	Cancer Classification and Risk Assessment Recommendation

Methoxyfenozide is classified as "not likely to be carcinogenic to humans," according to the revised 2005 Agency Guidelines for Carcinogen Risk Assessment.  The classification is based on lack of evidence of carcinogenicity in long-term dietary studies in the rat and the mouse, and lack of evidence of genotoxicity in the battery of mutagenicity studies.
 
4.5.4	Summary of Points of Departure and Toxicity Endpoints Used in Human Risk Assessment

Tables 4.5.4.1 and 4.5.4.2, below, summarize the dose and endpoint selection for dietary/non-occupational and occupational exposure:

Table 4.5.4.1  Summary of Toxicological Doses and Endpoints for Methoxyfenozide for Use in Dietary and Non-Occupational Human Health Risk Assessments
                              Exposure/ Scenario
                              Point of Departure
                        Uncertainty/FQPA Safety Factors
                RfD, PAD, Level of Concern for Risk Assessment
                        Study and Toxicological Effects
Acute Dietary (All Populations, including Infants and Children and Females 13-49 years of age)
No hazard was identified for a single oral exposure.
Chronic Dietary (All Populations)
NOAEL= 10.2 mg/kg/day
UFA= 10X
UFH= 10X
FQPA SF= 1
Chronic RfD = 0.10
mg/kg/day

cPAD = 0.10 mg/kg/day
Co-critical studies:
Combined oral chronic toxicity/carcinogenicity-rat
LOAEL = 411/491 mg/kg/day [M/F], based on hematological changes (decreased RBC parameters), periportal liver hypertrophy, thyroid hypertrophy and altered colloid; possibly increased adrenal weight.

Chronic oral toxicity-dog
NOAEL = 9.8/12.6 mg/kg/day[M/F]
LOAEL = 106.1/110.6 mg/kg/day, based on hematological changes (decreased RBC parameters, slight methemoglobinemia) and increased serum bilirubin.
Incidental Oral Short-Term (1-30 days)
There are no residential uses for methoxyfenozide that would result in significant post-application incidental oral exposure to children.
Dermal Short-Term (1-30 days) or Intermediate-term (1-6 months)
No toxicity, i.e., no hazard, was identified for dermal exposure.
Inhalation Short- Term (1-30 days) and Intermediate-Term (1-6 months)
NOAEL = 16.8 mg/kg/day
UFA=10X
UFH=10X
Residential LOC for MOE <= 100
Two-week oral range-finding study-dog

LOAEL = 90.8 mg/kg/day,  based on hematological changes (decreased RBC parameters, increased Heinz body count, reticulocyte counts, erythrocyte morphology and methemoglobinemia) and increased spleen weights.
Cancer (oral, dermal, inhalation)
Classification:  not likely to be carcinogenic to humans.
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and  used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures.  NOAEL = no observed adverse effect level.  LOAEL = lowest observed adverse effect level.  UF = uncertainty factor.  UFA = extrapolation from animal to human (interspecies).  UFH = potential variation in sensitivity among members of the human population (intraspecies).  FQPA SF = FQPA Safety Factor.  PAD = population adjusted dose (c = chronic).  RfD = reference dose.  MOE = margin of exposure.  LOC = level of concern.  N/A = not applicable.


Table 4.5.4.2 Summary of Toxicological Doses and Endpoints for Methoxyfenozide for Use in Occupational Human Health Risk Assessments
                              Exposure/ Scenario
                              Point of Departure
                              Uncertainty Factors
                     Level of Concern for Risk Assessment
                        Study and Toxicological Effects
Dermal Short-Term (1-30 days) or Intermediate-Term (1-6 months)
No toxicity, i.e., no hazard, was identified for dermal exposure
Inhalation Short-Term (1-30 days) and Intermediate-Term (1-6 months)
NOAEL = 16.8 mg/kg/day
UFA=10X
UFH=10X
Occupational LOC for MOE <= 100
Two-week oral range-finding study-dog

LOAEL = 90.8 mg/kg/day,  based on hematological changes (decreased RBC parameters, increased Heinz body count, reticulocyte counts, erythrocyte morphology and methemoglobinemia) and increased spleen weights.
Cancer (oral, dermal, inhalation)
Classification:  not likely to be carcinogenic to humans.
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose-response data and  used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures.  NOAEL = no observed adverse effect level.  LOAEL = lowest observed adverse effect level.  UF = uncertainty factor.  UFA = extrapolation from animal to human (interspecies).  UFH = potential variation in sensitivity among members of the human population (intraspecies).  MOE = margin of exposure.  LOC = level of concern.  N/A = not applicable 

5.0	Dietary Exposure and Risk Assessment 

5.1	Metabolite/Degradate Residue Profile
5.1.1	Summary of Plant and Animal Metabolism Studies

Acceptable studies are available depicting the metabolic fate of methoxyfenozide in target crops, rotational crops and livestock.  The main distinction between study results was that although methoxyfenozide does not undergo extensive metabolism in primary crops, it is highly metabolized in livestock and rotational crops.

The nature of methoxyfenozide residues in primary crops is adequately understood, based on acceptable metabolism studies in cotton, apples, grapes and rice.  Methoxyfenozide does not undergo extensive metabolism in primary crops.  HED has determined that the residue of concern for both the tolerance expression and risk assessment in primary crops is the parent compound only, methoxyfenozide.  

However, in rotational crops and livestock, additional metabolites are included in both the tolerance expression and the risk assessment.  The residue of concern in milk and ruminant tissues (other than liver and kidney) is parent compound; in ruminant liver and kidney methoxyfenozide and its RH-141,518 metabolite are of concern.  The residue of concern in poultry meat (muscle) and fat is parent methoxyfenozide; however, in eggs, poultry liver, and poultry meat byproducts, residues of concern include methoxyfenozide and its metabolite, RH-141,518.

In rotational crops, methoxyfenozide was highly metabolized by oxidation, demethylation and hydroxylation to non-conjugated metabolites, which were then conjugated with biomolecules, yielding bound residues and precursors in the sugar synthesis pathway.  The metabolites identified in the rotational crops were not similar to those found in the primary crop metabolism study.  The residues of concern in rotational crops include methoxyfenozide, its free phenol metabolite (RH-117,236), conjugated forms of the phenol metabolite (RH-151,055 and RH-152,072), and the metabolites RH-152,067, RH-131,157 and RH-152,071.  For enforcement purposes, the tolerance definition for rotated crops includes parent only in high-moisture crops, and the combined residues of parent and metabolites RH-151,055, RH-152,072 and RH-117,236 in low-moisture crops.
5.1.2	Summary of Environmental Degradation
Memo, K. Milians, Ph.D., Chemist, 8/17/2011, D388876

Methoxyfenozide is very persistent (t1/2 = 1 to 3 years in soil and water) and moderately mobile (Koc = 219  -  922 L/kgoc in various soils).  It is stable to photolysis and hydrolysis, is not significantly volatile, and degrades only very slowly by microbial activity.  Degradates are predominantly RH-117236 (3,5-dimethylbenzoic acid N-tert-butyl-N'-(3-hydroxy-2-methylbenzoyl)hydrazide) and RH-131154 (3-[N-tert-butyl-N'-(3-methoxy-2-methylbenzoyl)-hydrazinocarbonyl]-5-methylbenzoic acid), but these are only present at low concentrations. Because of its resistance to degradation and its mobility, methoxyfenozide has the potential to accumulate and to move off the site of application by leaching and erosion/runoff resulting in ground- and surface-water contamination.
5.1.3	Comparison of Metabolic Pathways

Methoxyfenozide is rapidly absorbed, distributed, metabolized and almost completely excreted within 48 hours in rats.  The major route of excretion was feces (86-97%) with lesser amounts in the urine (5-13%).  An enterohepatic circulation was observed.  The test material was metabolized principally by O-demethylation of the A-ring methoxy group and oxidative hydroxylation of the B-ring methyl groups followed by conjugation with glucuronic acid.  No significant sex-related or dose-dependent differences in metabolic disposition were noted.  Seven metabolites and the parent accounted for 74-90% of the administered dose in all groups.  These metabolites included RH-131,157, RH-141,518 and RH-117,236, metabolites also identified in residues in crops or livestock.

Metabolism of methoxyfenozide in other animals (poultry and ruminants) appears to be similar to its metabolism in rats.  Although methoxyfenozide does not undergo extensive metabolism in primary crops, it is highly metabolized in rotational crops.  Methoxyfenozide is metabolized by oxidation, demethylation and hydroxylation to non-conjugated metabolites, which were then conjugated with biomolecules, yielding bound residues and precursors in the sugar synthesis pathway.  This is the same basic pathway as observed in the rat.  The major drinking water degradates are also formed by ring hydroxylation and oxidation of methyl groups.  These degradates were also found in the rat.  Therefore, there were no significant residues in food or drinking water that were not seen in the rat.
5.1.4	Residues of Concern Summary and Rationale

The methoxyfenozide glucuronide conjugates are considered to be less toxic than the parent compound because glucuronide conjugation is well known to be a commonly occurring detoxification mechanism in mammalian species since it results in the formation of more polar, more water-soluble metabolites which are readily and easily excreted from the body (in this case, in the bile and urine).  Further, based on similarities of chemical structure, the non-conjugated metabolites would be expected to be no more toxic than the parent compound.  The metabolites were included in risk assessment and the tolerance expression, based on the potential for toxicity similar to that of the parent, as well as the potential for significant levels in crops and livestock, as well as the metabolites determined by the enforcement methods.

Primary Crops:  Based on acceptable metabolism studies in cotton, apples, grapes and rice, the nature of methoxyfenozide residues in primary crops is adequately understood.  HED concluded that the residue of concern for both the tolerance expression and the risk assessment in primary crops is methoxyfenozide. 

Livestock:  The qualitative nature of methoxyfenozide residues in livestock is also adequately understood, based on available ruminant and poultry metabolism studies.  HED determined that the residue of concern is the parent compound in milk and ruminant tissues (except meat byproducts), and in poultry meat and fat.  The residues of concern in meat byproducts and eggs are methoxyfenozide and its metabolite, RH-141,518.  

Rotational Crops:  The nature of methoxyfenozide residues in rotational crops is adequately understood, based on the adequate confined accumulation study.  For enforcement purposes, the tolerance definition for rotated crops includes parent only in high-moisture crops, and the combined residues of parent and metabolites RH-151,055, RH-152,072 and RH-117,236 in low-moisture crops.  Metabolites RH-152,067, RH-131,157 and RH-152,071 are also to be taken into account in risk assessments.  
	
Drinking Water:  The residues of concern in drinking water are the parent methoxyfenozide and the following degradates: RH-117236 (3,5-dimethylbenzoic acid N-tert-butyl-N'-(3-hydroxy-2-methylbenzoyl)hydrazide) and RH-131154 (3-[N-tert-butyl-N'-(3-methoxy-2-methylbenzoyl)-hydrazinocarbonyl]-5-methylbenzoic acid), but these are only present at low concentrations.

The toxicological and residue chemistry databases for methoxyfenozide have been examined to determine residue definitions for the purposes of setting tolerances and risk assessments.  The residue definitions are summarized in Table 5.1.4.

Table 5.1.4  Summary of Metabolites and Degradates to be included in the Risk Assessment and Tolerance Expression.[1]
Matrix
Residues included in Risk Assessment
Residues included in Tolerance Expression
Plants
Primary Crop
Parent methoxyfenozide
 Parent methoxyfenozide

Rotational Crop
 Parent methoxyfenozide and metabolites, RH 117,236; RH 151,055; RH 152,072; RH-152,067; 
RH-131,157; and RH-152,071
 Parent methoxyfenozide, and metabolites RH-151,055; RH-152,072; and RH-117,236
Livestock
Ruminant
Parent methoxyfenozide and metabolite RH-141,518
Parent methoxyfenozide and metabolite RH-141,518

Poultry
Parent  methoxyfenozide and metabolite 141,518
Parent  methoxyfenozide and metabolite 141,518
Drinking Water
Parent methoxyfenozide and degradates RH-117236 and RH-131154
Not Applicable
[1] Chemical structures for the residues of concern for tolerance enforcement purposes are provided in HED's Metabolism Committee  memorandum of 7/23/99 (D258034, W. Wassell).

5.2	Food Residue Profile

Memo, W. Drew, Chemist, 7/16/2013, D407758

Acceptable crop field trial data are available to support uses on herbs (subgroup 19A) except chives, dates, sorghum, and caneberry (subgroup 13-07A), and to establish tolerances for residues in the associated commodities.  Quantifiable residues were observed in/on all crop commodities.  Residue decline data indicate that residues generally declined for caneberries and sorghum.  The available data are adequate for risk assessment and tolerance assessment.  The results from these field trials are summarized in Table 5.2.

Because there are no processed commodities for caneberries or dates, processing studies were not required for these raw agricultural commodities (RACs).  The processed commodity for basil is dried basil, samples of which were produced at the field trial sites, and subsequently analyzed along with the fresh basil samples.  The submitted sorghum processing study data are adequate, and support a tolerance of 120 ppm in sorghum AGF.  This will be reflected in an increase of the currently established tolerance in AGF, from 2.0 to 120 ppm.  A tolerance in sweet sorghum syrup is not required.  

The available storage stability data are adequate, and support the storage conditions and durations for samples from the submitted caneberry, date, sorghum, and basil field trials, and the sorghum processing study.
  
Adequate livestock feeding studies are available for methoxyfenozide.  No livestock feeding studies were submitted with this petition.  Although the proposed tolerances for this action include an increase of the tolerance in sorghum grain, the revised estimated dietary burdens resulted in anticipated residues that do not exceed the tolerances currently established in livestock commodities.  Therefore, revisions to the currently established livestock tolerances are not needed as a result of the new uses.

TABLE 5.2	Summary of Residue Data from Crop Field Trials with Methoxyfenozide.
                                  Crop Matrix
                           Total Use Rate (lb ai/A)
                                   [g ai/ha]
                                  PHI (Days)
                             Residue Levels (ppm)
                                       
                                       
                                       
                                       n
                                     Min.
                                     Max.
                                     LAFT
                                     HAFT
                                    Median
                                     Mean
                                   Std. Dev.
                                     Basil
                            Fresh leaves and stems
                                  0.988-1.032
                                  [1107-1157]
                                       1
                                      10
                                     9.26
                                     47.2
                                      --
                                      --
                                     19.2
                                     21.7
                                     12.3
                                       
                                       
                                       
                                       5
                                      --
                                      --
                                     9.88
                                     43.4
                                     19.2
                                     21.7
                                     12.8
                            Dried leaves and stems
                                       
                                       
                                      10
                                     56.3
                                      194
                                      --
                                      --
                                      100
                                      110
                                     44.8
                                       
                                       
                                       
                                       5
                                      --
                                      --
                                     60.5
                                      188
                                      102
                                      110
                                     47.0
                                  Caneberries
                                  Caneberries
                                  0.744-0.778
                                   [834-872]
                                       3
                                      12
                                     0.62
                                      2.5
                                      --
                                      --
                                     1.90
                                     1.70
                                     0.65
                                       
                                       
                                       
                                       6
                                      --
                                      --
                                     0.68
                                      2.5
                                     1.90
                                     1.73
                                     0.67
                                     Dates
                                  Dried fruit
                                  0.501-0.933
                                       7
                                       8
                                      1.5
                                      3.3
                                      1.6
                                      2.3
                                      2.0
                                      2.0
                                     0.70
                                 Grain Sorghum
                                    Forage
                                  0.478-0.494
                                      2-4
                                      12
                                     0.70
                                      5.6
                                     0.77
                                      5.0
                                     2.15
                                     2.76
                                     1.45
                                     Grain
                                       
                                   11; 21-23
                                      12
                                     0.15
                                      2.6
                                     0.15
                                      2.3
                                     0.40
                                     0.72
                                     0.72
                                    Stover
                                       
                                     21-23
                                      12
                                     0.29
                                      9.7
                                     0.45
                                      7.6
                                     2.95
                                     3.18
                                     2.39
                                 Sweet Sorghum
                                    Stalks
                                     0.481
                                       3
                                       1
                                     0.045
                                     0.18
                                     0.11
                                     0.11
                                     0.11
                                     0.11
                                      NA

Adequate residue data are available to support proposed updates to crop group tolerances, and to establish indirect or inadvertent tolerances.  Specifically, tolerances in the updated crop groups 8-10 and 11-10, and in the updated subgroups 13-07F and 13-07G were requested.  Tolerances in sugar apples, cherimoyas, atemoyas, custard apples, ilamas, soursops, and biribas were also requested, based on translation of avocado residues.  Additionally, indirect or inadvertent tolerances in the rapeseed subgroup (20A) and the sunflower subgroup (20B) were requested.  The requested changes for the rapeseed and sunflower subgroups are based on 2012 recommendations by EPA.  Other changes are supported by data previously reviewed by the Agency in 2009.  

5.3	Water Residue Profile
Memo, K. Milians, Ph.D., Chemist, 4/23/2013, D407566

The estimated drinking water concentrations (EDWCs) are based on all current methoxyfenozide uses as well as the new proposed uses.   Surface water residues were modeled with the Pesticide Root Zone Model and Exposure Analysis Modeling System (PRZM-EXAMS), using EFED's standard index reservoir which incorporates flow into and out of the reservoir.  Groundwater residues were estimated using the Pesticide Root Zone Model  -  Ground Water (PRZM-GW) model, which accounts for pesticide fate in the crop root zone and multiple years of application.  The surface water values are based on the existing globe artichoke use represented by the CA lettuce scenario with an application rate of 0.25 lbs. a.i./acre/application and a total of 1.0 lb a.i./acre/season.  The estimated drinking water concentrations (EDWCs) are listed in Table 2. The EDWC used in this assessment is bolded in the table below, with the value of 251 ppb coming from the groundwater residues estimated by the PRZM-GW model.  

There remains an outstanding data requirement for monitoring of surface water and sediment in a representative sample of high use areas in proximity to surface water.  Additionally, EFED continues to have concerns about the persistence of methoxyfenozide. This persistence makes it plausible that methoxyfenozide may pose a greater long-term drinking water exposure concern than what is suggested by the screening-level assessment.  In particular, once introduced into the environment, this compound could travel to key aquatic environmental compartments, such as aquatic sediment, and persist for extended periods of time.  Thus, there are significant uncertainties regarding the potential long-term drinking water exposure associated with the use of methoxyfenozide.  Therefore EFED has used a conservative approach to modeling potential residues in ground water sources of drinking water.  

Table 5.3.	Tier II estimated drinking water concentrations (EDWCs) resulting from 			applications of methoxyfenozide (PRZM-EXAMS)
                            Drinking water source 
                                      Use
                                (modeled rate)
                           1-in-10 year acute (ppb)
                          1-in-10 year chronic (ppb)
                            30- year average (ppb)
                                 Surface water
                             (aerial application)
                                Globe Artichoke
              (0.25 lb a.i./A x 4 applic.; total of 1.0 lb/A/yr)
                                     77.7
                                     51.6
                                     37.4
                                 Surface water
                             (ground application)
                                Globe Artichoke
              (0.25 lb a.i./A x 4 applic.; total of 1.0 lb/A/yr)
                                     77.4
                                     50.4
                                     35.8
                    Tier I EDWCs for Groundwater (PRZM-GW)
                                 Crop/Scenario
                          Highest Daily value (ug/L)
                       Post Breakthrough Average (ug/L)
                  Average Simulation Breakthrough Time (days)
                          Fruiting Vegetable/WI corn
                                      251
                                      214
                                    8684.63

5.4	Dietary Risk Assessment
Memo, E. Holman, 7/16/2013, D412460
5.4.1	Description of Residue Data Used in Dietary Assessment

For this analysis existing and recommended tolerance levels were used, as well as 100% CT assumptions for all commodities.  DEEM (Version 7.81) default processing factors were used for most processed commodities that do not have individual tolerances; the only exception was an Alternative Risk Integration Assessment Team (ARIA) determined processing factor of 0.2X for orange juice (D358341, D. Rate, 6/10/2009) from a reviewed processing study.  The existing tolerances for livestock commodities were considered adequate (D407758, W. Drew, 7/16/13).  

Drinking water was incorporated directly into the dietary assessment using the maximum chronic concentration for groundwater generated by the Pesticide Root Zone Model  -  Ground Water (PRZM-GW) at 251 ppb.

5.4.2	Percent Crop Treated Used in Dietary Assessment

The chronic dietary exposure assessment, based on food and drinking water, includes the assumption of 100% CT for all existing and proposed uses.  
5.4.3	Acute Dietary Risk Assessment

There was no appropriate endpoint identified for assessing acute dietary exposure; therefore, no acute dietary risk assessment was performed.
5.4.4	Chronic Dietary Risk Assessment

An unrefined chronic dietary analysis for methoxyfenozide was conducted using tolerance level residues and 100% CT for all existing and proposed primary crop uses, and additional residues of concern in livestock commodities.  Methoxyfenozide chronic dietary (food + drinking water) exposure estimates using the DEEM-FCID(TM) software are below HED's level of concern for the U.S. population and each of the population subgroups.  Chronic dietary exposure was 31% of the cPAD for the U.S. population.  The chronic dietary exposure for the highest reported exposed population subgroup, children 1-2 years old, was 84% of the cPAD.  The results of the analysis indicate that chronic risk from the dietary (food + drinking water) exposure to methoxyfenozide will not exceed HED's LOC for the general U.S. population, nor any other population subgroups.  Based on the very conservative assumptions used, actual dietary exposure to methoxyfenozide form food and drinking water is expected to be significantly lower than the exposures presented in Table 5.4.4.

The results of the chronic dietary exposure analysis are reported in the Summary Table 5.4.4.

Table 5.4.4.  Summary of Dietary Exposure and Risk for Methoxyfenozide.  
                            Population Subgroup[1]
                         DEEM Acute Dietary Analysis,
                               95[th] Percentile
                         DEEM Chronic Dietary Analysis
                                       
                             Exposure (mg/kg/day)
                                    % aPAD
                             Exposure (mg/kg/day)
                                    % cPAD
General U.S. Population

                                       
                                       
                                    NA [2]
                                       
                                    0.031520
                                       31
All Infants (< 1 year old)
                                       
                                    0.047975
                                       47
Children 1-2 years old
                                       
                                    0.085207
                                       84
Children 3-5 years old
                                       
                                   0.065025
                                       64
Children 6-12 years old
                                       
                                    0.036288
                                       36
Youth 13-19 years old
                                       
                                   0.023942
                                       24
Adults 20-49 years old
                                       
                                    0.027714
                                       27
Adults 50+ years old
                                       
                                    0.027499
                                       27
Females 13-49 years old
                                       
                                    0.028308
                                       28
[1] Values for the population with the highest risk for each type of risk assessment are bolded.  
[2] NA = Not Applicable; no acute dietary endpoint was identified for these population subgroups.
5.4.5	Cancer Dietary Risk Assessment

HED classified methoxyfenozide as "not likely to be carcinogenetic to humans" and, therefore, cancer risk is not of concern for methoxyfenozide.

6.0 Residential (Non-Occupational) Exposure/Risk Characterization
Memo, M. Collantes 2/27/2012; D389739
Memo, M. Collantes 6/07/2013; D411612

There are no new proposed residential uses at this time; however, there are existing residential ornamental uses that were previously reassessed to reflect updates to HED's 2012 Residential SOPs along with policy changes for body weight assumptions (M. Collantes, D389739, 02/27/12).  In order to incorporate residential exposure into the short-term aggregate risk assessment, a summary of the residential exposure and risk estimates resulting from the use of methoxyfenozide on ornamentals is provided below.

6.1	Residential Handler Exposure

The Intrepid 2F label indicates that it is to be used on trees, shrubs, foliage plants and flowers grown in commercial nurseries and greenhouses, Christmas tree farms, outdoor landscapes areas, parks, recreational areas, institutional grounds and "residential property".  Since the label does not identify this product as a restricted use, a residential handler exposure assessment was performed to be protective of potential home owner exposure.  The following use scenarios and sources of unit exposures were used to assess residential handler exposures:

 Mixing/Loading/Applying for Sprays Using Manually Pressurized Handwand
 Mixing/Loading/Applying for Sprays with Back-Pack Sprayer 
 Mixing/Loading/Applying for Sprays with Hose-end Sprayer 

HED's LOC is a MOE greater than or equal to 100 for residential exposure.  A quantitative dermal assessment for residential handlers was not conducted since there is no systemic toxicity associated with dermal exposure to methoxyfenozide.  Handler inhalation exposure scenarios resulted in MOEs greater than 100, ranging from 76,000 to greater than 3 million, and these risk estimates are not of concern.  Although a point of departure from an oral study was used to assess the handler inhalation risks, the calculated MOEs are all >76,000, thus providing an ample margin of safety to account for any uncertainties in the route-to-route extrapolation.  Handler exposure and risk estimates are summarized in Table 6.1.  

      Table 6.1.:  Residential Handler Exposure and Risk Estimates for Methoxyfenozide
Exposure Scenario
Application Rate [a]
(lb ai/gal)
Amount Treated [b]
(gallons)
Inhalation 
Unit Exposure b 
(mg/lb ai)
Inhalation Dose [c] (mg/kg/day)
Inhalation MOE [d]
                   Liquid with Manually Pressurized Handwand
                                     0.025
                                       5
                                     0.018
                                   0.0000283
                                    590,000
Liquid with 
Back Pack
                                       
                                       5
                                     0.14
                                    0.00022
                                    76,000
Liquid with Hose-end Sprayer

                                       
                                      11
                                    0.0014
                                  0.00000484
                                   3,500,000
      a. In accordance with Intrepid(R) 2F (Reg.  No.: 62719-442) label: 0.025 lb ai per gallon for treatment of ornamentals  (0.25 lb ai/A / 10 gallons/A for mist blowers and air blast sprayers)
      b. In accordance with revised Residential (Garden and Trees) SOP
      c. Inhalation  dose (mg/kg/day) = inhalation unit exposure (mg/lb ai) * application rate * acres treated / body weight (80 kg)
      d. Inhalation MOE = NOAEL (16.8 mg/kg/day)/ Inhalation Dose (mg/kg/day)

6.2	Dermal Post-application Exposure

Although there is potential for post-application dermal exposure as a result of the use on ornamentals, there's no dermal toxicity associated with this exposure, and a dermal post-application exposure assessment was not conducted.  Furthermore, post-application oral exposure to children is not expected since the extent to which young children engage in activities associated with areas where residential ornamentals are grown or utilize these areas for prolonged periods of play is low.  Therefore an incidental oral endpoint was not selected and an incidental oral post-application exposure assessment was not conducted.  
 
6.3	Inhalation Post-application Exposure

Based on the Agency's current practices, a quantitative post-application inhalation exposure assessment was not performed for methoxyfenozide at this time primarily because of the low acute inhalation toxicity (Toxicity Category III and IV), vapor pressure (1 x 10[-7] mm Hg at 25ºC), and the low proposed use rate (0.31 lb ai/A).  However, volatilization of pesticides may be a source of post-application inhalation exposure to individuals nearby pesticide applications.  The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on March 2, 2010.  The Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies and procedures to identify the need for and, subsequently, the way to incorporate post-application inhalation exposure into the Agency's risk assessments.  If new policies or procedures are developed, the Agency may revisit the need for a quantitative post-application inhalation exposure assessment for methoxyfenozide.

6.5	Spray Drift

Spray drift is always a potential source of exposure to residents nearby to spraying operations.  This is particularly the case with aerial application, but, to a lesser extent, could also be a potential source of exposure from the ground application method employed for methoxyfenozide.  The Agency has been working with the Spray Drift Task Force, EPA Regional Offices and State Lead Agencies for pesticide regulation and other parties to develop the best spray drift management practices (see the Agency's Spray Drift website for more information.  The Agency has completed its evaluation of the new database submitted by the Spray Drift Task Force, a membership of U.S. pesticide registrants, and is developing a policy on how to appropriately apply the data and the AgDRIFT computer model to its risk assessments for pesticides applied by air, orchard airblast and ground hydraulic methods.  After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce off-target drift with specific products with significant risk estimates associated with drift.

Although a quantitative residential post-application inhalation exposure assessment was not performed as a result of pesticide drift from neighboring treated agricultural fields, an inhalation exposure assessment was performed for flaggers.  This exposure scenario is representative of a worst case inhalation (drift) exposure and may be considered protective of most outdoor agricultural and commercial post-application inhalation exposure scenarios.   

6.0 Aggregate Exposure/Risk Characterization

In accordance with the FQPA, HED must consider and aggregate (add) pesticide exposures and risks from three major sources: food, drinking water, and residential exposures.  In an aggregate assessment, exposures from relevant sources are added together and compared to quantitative estimates of hazard (e.g., a NOAEL or PAD), or the risks themselves can be aggregated.  When aggregating exposures and risks from various sources, HED considers both the route and duration of exposure.  In the case of methoxyfenozide, chronic aggregate risks result from exposure through food and water only.  For short-term risk, adult residential handlers' inhalation exposure was combined with background exposure from food and water.  As previously discussed (see Section 6.2), there are no residential uses for methoxyfenozide that would result in significant post-application exposure to children, based on ornamental use only. Therefore, aggregate exposure and risk for children are equivalent to those from food and water (see Section 5.4). 
  
7.1	Acute Aggregate Risk

There are no single dose effects associated with methoxyfenozide, and therefore no acute aggregate risk.

2.2 Short-Term Aggregate Risk

The residential handler exposure from applying methoxyfenozide using a backpack (Table 6.1) was combined with the chronic dietary exposure from the mostly highly exposed adult (General U.S. Population) sub-population, to determine aggregate exposure and risk as shown in Table 7.2.  The aggregate MOEs are above the LOC of 100, and therefore the aggregate risk estimate is not of concern.

Table 7.2.  Short-Term Aggregate Risk Calculations for Methoxyfenozide.
                                  Population
                                NOAEL mg/kg/day
                                    LOC[1]
                      Max Allowable Exposure[2] mg/kg/day
                   Average Food and Water Exposure mg/kg/day
                       Residential Exposure mg/kg/day[3]
                          Total Exposure mg/kg/day[4]
                Aggregate MOE (food, water, and residential)[5]

Adult (Handler)
                                     16.8
                                      100
                                     0.168
                                   0.031520
                                    0.00022
                                    0.03174
                                      530
[1] The LOC is based on the standard inter- and intra- species uncertainty factors totaling 100.  The FQPA Safety Factor has been reduced to 1X.
[2] Maximum Allowable Exposure (mg/kg/day) = NOAEL/LOC
[3] Residential Exposure (Adult Handler) = Inhalation Exposure (Table 6.1).  
[4] Total Exposure = (Avg. Food & Water Exposure + Residential Exposure)
[5] Aggregate MOE = [NOAEL16.8 mg/kg/day/Total Exposure mg/kg/day]

7.3	Chronic Aggregate Risk

Chronic aggregate risk is equivalent to chronic dietary exposure and risk, which is not of concern.  Refer to Section 5.4.4.

6.0 Cumulative Exposure/Risk Characterization

Unlike other pesticides for which EPA has followed a cumulative risk approach based on a common mechanism of toxicity, EPA has not made a common mechanism of toxicity finding as to methoxyfenozide and any other substances and methoxyfenozide does not appear to produce a toxic metabolite produced by other substances. For the purposes of this action, therefore, EPA has not assumed that methoxyfenozide has a common mechanism of toxicity with other substances. For information regarding EPA's efforts to determine which chemicals have a common mechanism of toxicity and to evaluate the cumulative effects of such chemicals, see the policy statements released by EPA's Office of Pesticide Programs concerning common mechanism determinations and procedures for cumulating effects from substances found to have a common mechanism on EPA's website at http://www.epa.gov/pesticides/cumulative/.

7.0 Occupational Exposure/Risk Characterization

Memo, M. Collantes 6/07/2013; D411612

Methoxyfenozide is intended for use by commercial and professional applicators for the control of lepidopterous pests on herbs (subgroup 19A) except chives, dates, sorghum, and caneberries (subgroup 13-07A).    In addition, California is requesting a Section 18 for use of Intrepid 2F on dates/palm only.   Methoxyfenozide is an insecticide currently registered for use on ornamentals and on numerous agricultural crops, such as dried peas and beans (subgroup 6C; except soybean), pomegranate, popcorn, citrus fruits (group 10-10), and root vegetables, except sugar beet (subgroup 1B).  

It may be applied through a variety of application methods including: aerial, ground equipment (airblast and groundboom), hand held equipment (backpack sprayer, manually-pressurized handwand and hand gun), and hose end sprayer.  Therefore, there is potential for short- and intermediate-term occupational handler and post-application exposure; long-term exposures are not expected.  
9.1	Occupational Handlers

Based upon the proposed use pattern, HED expects the most highly exposed occupational pesticide handler scenarios to be:

    * Mixing/loading liquid for aerial application to orchards (i.e., caneberries) and high acreage field crops (i.e.,herbs and sorghum)
    * Mixing/loading liquid for airblast to orchards (i.e., caneberries and dates)
    * Mixing/loading liquid for groundboom to high acreage field crops (i.e., herbs and sorghum)
    * Mixing/loading liquid for groundboom to low acreage field crops (i.e, caneberries)
    * Applying sprays via aerial application to orchards (i.e., caneberries) and high acreage field crops (i.e., herbs and sorghum)
    * Applying sprays via airblast to orchards (i.e., caneberries and dates)
    * Applying sprays via groundboom to high acreage field crops (i.e.,herbs and sorghum)
    * Flagger for aerial application to orchards (i.e., caneberries) and high acreage field crops (i.e.,herbs and sorghum)
    * Mixing/loading/applying liquid via backpack (ground/soil directed) to orchards (i.e., caneberries and dates)
    * Mixing/loading/applying liquid via mechanically pressurized handwand (broadcast foliar and drench) to orchards (i.e., caneberries and dates)
       
 Handler exposure is expected to be short- or intermediate-term in duration, based on information provided on proposed labels.  However, since the short- and intermediate-term toxicological endpoints are the same; only short-term dermal exposures have been assessed.  HED estimates exposure based on day-0 residues.  Using day-0 residues to assess intermediate-term exposure does not take into account dissipation of residues over time and thus results in a conservative estimate.  Therefore, the short-term exposure assessment represents the worst case scenario and is protective of intermediate-term exposure.  Long-term exposures are not expected, based on the existing and proposed use pattern.

No chemical-specific handler exposure data were submitted in support of the proposed uses, and therefore HED relied on the best available surrogate data to complete the occupational handler assessment.  

The proposed product label involved in this assessment directs applicators and other handlers to wear long sleeved shirt and long pants, shoes plus socks, and chemical-resistant gloves.  HED typically assesses handler exposure using "baseline" clothing assumptions, and if risks of concern are identified, the use of personal protective equipment (PPE) may be incorporated into the exposure assessment.  In the case of methoxyfenozide, there is no toxicity via the dermal route, and only inhalation exposures were assessed.  Table 9.1 presents the estimated risks for workers, based on short-term inhalation exposures at baseline (i.e. single layer clothing and no respirator), and in some situations the use of gloves or engineering controls for aerial applications.  Short- term risks for handlers are not of concern (i.e., MOEs were equal to or greater than 100) with inhalation MOEs ranging from 20,000 to 3,100,000.    No additional PPE (i.e., respirators) were needed to achieve MOEs above the LOC of 100.

Table 9.1.  Occupational Handler Non-Cancer Exposure and Risk Estimates for  Methoxyfenozide.
                               Exposure Scenario
                                Crop or Target
                           Inhalation Unit Exposure
                                 (μg/lb ai)[1]
                                    Maximum
                              Application Rate[2]
                    Area Treated or Amount Handled Daily[3]
                                  Inhalation
                                       
                                       
                               Mitigation Level
                                       
                                       
                              Dose (mg/kg/day)[4]
                                    MOE[5]
                                 Mixer/Loader
                                    Aerial 
                             Orchard (caneberries)
                                       
                                     0.219
                                (no respirator)
                                 0.25 lb ai/A
                                     350 A
                                    0.00024
                                    70,000

                  High acreage field crop (herbs and sorghum)
                                       
                                       
                                    1200 A
                                    0.00082
                                    20,000
                                  Groundboom
                                       
                  High acreage field crop (herbs and sorghum)
                                       
                                 0.25 lb ai/A
                                     200 A
                                   0.000138
                                    120,000
                                   Airblast
                        Orchard (caneberries and dates)
                                       
                                 0.31 lb ai/A
                                     40 A
                                    0.0027
                                    490,000
                                  Applicator
                                    Aerial
                             Orchard (caneberries)
                                       
                                       
                                    0.0049
                                       
                                 0.25 lb ai/A
                                     350 A
                                   0.0000053
                                   3,100,000

                  High acreage field crop (herbs and sorghum)
                                       
                                       
                                    1200 A
                                   0.000018
                                    910,000
                                  Groundboom
                  High acreage field crop (herbs and sorghum)
                                     0.34 
                                (no respirator)
                                 0.25 lb ai/A
                                     200 A
                                   0.000213
                                    79,000
                                   Airblast
                        Orchard (caneberries and dates)
                                     4.71
                                (no respirator)
                                 0.31 lb ai/A
                                     40 A
                                    0.00073
                                    23,000
                                    Flagger
                                    Aerial
     Orchard and High acreage field crop (caneberries, herbs and sorghum)
                                     0.35
                                (no respirator)
                                 0.25 lb ai/A
                                     350 A
                                    0.00038
                                    44,000
                            Mixer/Loader/Applicator
                                   Back Pack
                                       
                        Orchard (caneberries and dates)
                                     2.58
                                (no respirator)
                               0.0083 lb ai/gal
                                    40 gals
                                   0.000010
                                   1,600,000
                       Mechanically Pressurized Handgun
                                       
                                       
                                      3.9
                                (no respirator)
                                       
                                   1000 gals
                                    0.00040
                                    41,000
1	Based on the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table" ([DATE]); Level of mitigation: Baseline, PPE, Eng. Controls.
2	Based on registered or proposed label (Reg. No. 62719-442).
3	Exposure Science Advisory Council Policy #9.1.
6	Inhalation Dose = Dermal Unit Exposure (μg/lb ai) x Conversion Factor (0.001 mg/μg) x Application Rate (lb ai/acre or gal) x Area Treated or Amount  Handled Daily (A or gal/day) / BW (80 kg).
7	Inhalation MOE = Inhalation NOAEL (16.8 mg/kg/day) / Inhalation Dose (mg/kg/day).

9.2	Post-application Risk
9.2.1	Post-application Dermal Exposure

Since there's no dermal toxicity associated with methoxyfenozide, a dermal post-application exposure and risk assessment was not conducted.  
9.2.2.	Post-application Inhalation Exposure

Based on the Agency's current practices, a quantitative post-application inhalation exposure assessment was not performed for methoxyfenozide at this time primarily because of the low acute inhalation toxicity (Toxicity Category III and IV), vapor pressure (1 x 10[-7] mm Hg), and the low proposed use rate (0.31 lb ai/A).  However, there are multiple potential sources of post-application inhalation exposure to individuals performing post-application activities in previously treated fields.  These potential sources include volatilization of pesticides and resuspension of dusts and/or particulates that contain pesticides.  The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009, and received the SAP's final report on March 2, 2010. The Agency is in the process of evaluating the SAP report as well as available post-application inhalation exposure data generated by the ARTF and may, as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to incorporate occupational post-application inhalation exposure into the Agency's risk assessments.  If new policies or procedures are put into place, the Agency may revisit the need for a quantitative occupational post-application inhalation exposure assessment for methoxfenozide.

Although a quantitative occupational post-application inhalation exposure assessment was not performed, an inhalation exposure assessment was performed for occupational/commercial handlers.  Handler exposure resulting from application of pesticides outdoors is likely to result in higher exposure than post-application exposure.  Therefore, it is expected that these handler inhalation exposure estimates would be protective of most occupational post-application inhalation exposure scenarios.

Restricted Entry Interval
 The REI specified on the proposed label is based on the acute toxicity of methoxyfenozide. 
 Methoxyfenozide is classified as Toxicity Category III via the dermal route and Toxicity
 Category IV for skin irritation potential.  It is not a skin sensitizer.  Since a dermal endpoint was
 not selected a post-application risk estimates were not required  for post-application activities. 
 Under 40 CFR 156.208 (c) (2) (iii), ai's classified as Acute III or IV for acute dermal, eye
 irritation and primary skin irrigation are assigned a 12-hour REI.  Therefore, the [156 subpart K]
 Worker Protection Statement interim REI of 12 hours is adequate to protect agricultural workers
 from post-application exposures to methoxyfenozide.    

However, methoxyfenozide is not classified as a carcinogen or a neurotoxicant, nor is it associated with known reproductive or developmental effects.  Therefore, methoxyfenozide is a candidate for a 4-hour REI which appears on the proposed supplemental and master label.  

10.0	References

D407758.  Methoxyfenozide.  Petition to Establish Permanent Tolerances (and Section 3 Registration) for Residues Resulting from Food/Feed Uses of the Insecticide on Herbs (Subgroup 19A) Except Chives, Caneberries (Subgroup 13-07A), Dates and Sorghum; to Update Pome Fruits from Group 11 to 11-10, and Fruiting Vegetables from Group 8 to 8-10; to Extend the Tolerance in Grapes to Small Vine Climbing Fruits Except Fuzzy Kiwifruit (Subgroup 13-07F), the Tolerance in Strawberries to Low Growing Berries (Subgroup 13-07G) Except Cranberry, and the Tolerance in Avocadoes to Various Tropical Tree Fruits; to Delete the Tolerances in Dried Shelled Peas and Beans and Add a Tolerance in Subgroup 6C; and to Establish Rotational Crop Tolerances in the Rapeseed (Subgroup 20A) and Sunflower (Subgroup 20B) Oilseed Subgroups.  Summary of Analytical Chemistry and Residue Data.  W. Drew, 7/16/13

D407566.  Drinking Water Assessment for the IR-4 New Use Petitions for the Use of Methoxyfenozide on Herb Subgroup 19A (except chives), Dates, Sorghum, Fruiting Vegetable Group 8-10, Pome Fruit Group 11-10, Berry Subgroups 13-07 A, F & G and Tropical Tree Fruits.  K. Milians, 4/23/13.

D412460.  Methoxyfenozide.  Chronic Aggregate Dietary (Food and Drinking Water) Exposure and Risk Assessment for the Section 3 Registration on Herbs (Subgroup 19A) Except Chives, Caneberries (Subgroup 13-07A), Dates and Sorghum; to Establish Rotational Crop Tolerances in the Rapeseed (Subgroup 20A) and Sunflower (Subgroup 20B) Oilseed Subgroups; as well as to extend and update Crop Group Tolerances on Multiple Commodities.  E. Holman, 7/16/2013.

D394924.  Methoxyfenozide.  Occupational and Residential Exposure Assessment for New Uses on Root Vegetables and Citrus.  M. Collantes, 2/27/12.

D394924.  Methoxyfenozide.  Occupational and Residential Exposure Assessment for a Proposed Use on Dates, Sorghum, Herbs (subgroup 19A except chives) and Caneberries (subgroup 13-07A).  M. Collantes, 6/7/13.

D258034.  PP#8F5004 & PP#8F5006:  Methoxyfenozide.  Conclusions of the 7/13/99 Meeting of the Metabolism Assessment Review Committee.  W. Wassell, 7/13/99.

Methoxyfenozide:  Summary of Hazard and Science Policy Council (HASPOC) Meeting of March 29, 2012:  Recommendation on the need for a 28-day inhalation study.  K. Rury and J. Van Alstine, 03/23/12.

Appendix A.  Toxicology Profile and Executive Summaries

A.1	Toxicology Data Requirements
The requirements (40 CFR 158.340) for food use for methoxyfenozide are in Table 1. Use of the new guideline numbers does not imply that the new (1998) guideline protocols were used.

                                     Study
                                   Technical

                                   Required
                                   Satisfied
870.1100    Acute Oral Toxicity	
870.1200    Acute Dermal Toxicity	
870.1300    Acute Inhalation Toxicity	
870.2400    Primary Eye Irritation	
870.2500    Primary Dermal Irritation	
870.2600    Dermal Sensitization	
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
870.3100    Oral Subchronic (rodent)	
870.3150    Oral Subchronic (nonrodent)	
870.3200    21-Day Dermal	
870.3250    90-Day Dermal	
870.3465    28-or 90-Day Inhalation	
                                      yes
                                      yes
                                      yes
                                      no
                                      no*
                                      yes
                                      yes
                                      yes
                                       -
                                      no
870.3700a  Developmental Toxicity (rodent)	
870.3700b  Developmental Toxicity (nonrodent)	
870.3800    Reproduction	
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
870.4100a  Chronic Toxicity (rodent)	
870.4100b  Chronic Toxicity (nonrodent)	
870.4200a  Oncogenicity (rat)	
870.4200b  Oncogenicity (mouse)	
870.4300    Chronic/Oncogenicity	
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
870.5100    Mutagenicity -- Gene Mutation - bacterial	
870.5300    Mutagenicity -- Gene Mutation - mammalian	
870.5xxx    Mutagenicity -- Structural Chromosomal Aberrations	
870.5xxx    Mutagenicity -- Other Genotoxic Effects	
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
870.6100a  Acute Delayed Neurotoxicity (hen)	
870.6100b  90-Day Neurotoxicity (hen)	
870.6200a  Acute Neurotoxicity Screening Battery (rat)	
870.6200b  90-Day Neurotoxicity Screening Battery (rat)	
870.6300    Develop. Neurotoxicity	
                                      no
                                      no
                                      yes
                                      yes
                                      no
                                       -
                                       -
                                      yes
                                      yes
                                       -
870.7485    General Metabolism	
870.7600    Dermal Penetration	
870.7800    Immunotoxicity	
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
                                      yes
Special Studies for Ocular Effects
         Acute Oral (rat)	
         Subchronic Oral (rat)	
         Six-month Oral (dog)	
                                        
                                      no
                                      no
                                      no
                                       
                                       -
                                       -
                -
* The required repeated dose inhalation toxicity study has been waived.


A.2	Toxicity Profiles

Table A.2.1	Acute Toxicity Profile  -  Methoxyfenozide technical
Guideline No.
Study Type
MRID(s)
                                    Results
                               Toxicity Category
870.1100
Acute oral [rat]
                                   44144415
LD50 >5000 mg/kg, both sexes
                                      IV
870.1100
Acute oral [mouse]
                                   44144416
LD50 >5000 mg/kg, both sexes
                                      IV
870.1200
Acute dermal [rat]
                                   44144418
LD50 >2000 mg/kg, both sexes
                                      III
870.1300
Acute inhalation [rat]
                                   44144420
LC50 >4.3 mg/L, both sexes
                                      IV
870.2400
Acute eye irritation [rabbit]
                                   44144422
Very mild irritant
                                      IV
870.2500
Acute dermal irritation [rabbit]
                                   44144424
Not an irritant
                                      IV 
870.2600
Skin sensitization [Guinea pig]
                                   44144426
Not a sensitizer
                                      N/A


Table A.2.2	Subchronic, Chronic and Other Toxicity Profile
                                Guideline No. 
                                  Study Type
                    MRID No. (year)/ Classification /Doses
                                    Results
Nonguideline
2-week oral range-finding (rat)
44617722 (1995)
Acceptable/nonguideline
0, 50, 250, 1000, 5000, 20,000 ppm in the diet
[note:  mg/kg/day equivalents not calculated; see 90-day oral rat for mg/kg/day]
NOAEL = 250 ppm (approximately 17.0/19.1 mg/kg/day M/F based on main study doses)
LOAEL = 1000 ppm (approximately 69.3/72.4 mg/kg/day M/F based on main study doses), based on thyroid gland hypertrophy/hyperplasia in males and females, and increased adrenal hypertrophy of zona fasciculata in females.
At >=5000 ppm, increased abs/rel liver and adrenal weights, hepatocellular hypertrophy
870.3100

90-Day oral toxicity (rat)
44617722 (1995)
Acceptable/guideline

0, 50, 250, 1000, 5000, 20,000 ppm in the diet

M: 0, 3.4, 17.0, 69.3, 353.4, 1368.8 mg/kg/day
F: 0, 3.7, 19.1,72.4, 379.3, 1531.2 mg/kg/day
NOAEL =  69.3/72.4 mg/kg/day [M/F]
LOAEL = 353.4 mg/kg/day [M/F] based on periportal hepatocellular hypertrophy and increased liver weight.
At 1368.8/1531.2 mg/kg/day:  decreased RBC and Hg in females.
870.3100

90-Day oral toxicity (mouse)
44617723 (1995)	
Acceptable/guideline
0, 70, 700, 2500, 7000 ppm in the diet
M:  0, 11.9, 112.5, 428.2, 1149.3 mg/kg/day;
F:  0, 17.4, 165.1, 589.4, 1742.1 mg/kg/day	
NOAEL = 428.2/589.4 mg/kg/day [M/F]
LOAEL = 1149.3/1742.1 mg/kg/day [M/F] based on decreased body weight gain.
Nonguideline
2-week range-finding (dog)
44617724 (1995)
Acceptable/nonguideline
0, 300, 3500, 15,000 or 30,000 ppm in the diet (2 animals/sex/dose)
M:  0, 11.7-14.7, 141.6-167.6, 264.7-370.4, 571.4-631.7, 1113.7-1337.0 mg/kg/day;
F:  0, 13.3-16.8, 90.8-184.8, 285.9-336.8, 582.3-630.9, 1092.6-1169.1 mg/kg/day
NOAEL = 11.7-14.7/13.3-16.8 mg/kg/day [M/F]
LOAEL = 141.6-167.6/90.8-184.8 mg/kg/day [M/F], based on hematological changes (decreased RBC parameters, increased Heinz body count, reticulocyte counts, erythrocyte morphology and methemoglobinemia) and increased spleen weights.

At >=264.7 mg/kg/day, bilirubinemia 
870.3150

90-Day oral toxicity (dog)
44617724 (1995)
Acceptable/guideline
0, 15, 50, 500 or 5000 ppm in the diet
M:  0, 0.6, 2.0, 21.4, 197.5 mg/kg/day;
F:  0, 0.6, 1.9, 20.4, 208.8 mg/kg/day
NOAEL =  197.5/208.8 mg/kg/day [M/F]
LOAEL >197.5/208.8 mg/kg/day [M/F](HDT).
870.3200

28-Day dermal toxicity (rat)
44517725 (1998)
Acceptable/guideline
0, 75, 300, 1000 mg/kg/day
Systemic NOAEL = 1000 mg/kg/day
Systemic LOAEL  > 1000 mg/kg/day (HDT)
Local dermal NOAEL = 1000 mg/kg/day
Local dermal LOAEL  > 1000 mg/kg/day (HDT)

870.3700a

Prenatal developmental in (rat)
44638201 (1994)
Acceptable/guideline
0, 100, 300, 1000 mg/kg/day (gavage)
Maternal NOAEL = 1000 mg/kg/day
LOAEL >1000 mg/kg/day (HDT)
Developmental NOAEL = 1000 mg/kg/day
LOAEL >1000 mg/kg/day (HDT)
870.3700b

Prenatal developmental in (rabbit)
44617726 (1997)
Acceptable/guideline
0, 100, 300, 1000 mg/kg/day (gavage)
Maternal NOAEL = 1000 mg/kg/day
LOAEL > 1000 mg/kg/day (HDT)
Developmental NOAEL = 1000 mg/kg/day
LOAEL > 1000 mg/kg/day (HDT)
870.3800

Reproduction and fertility effects
(rat)
44617727 (1997)
Acceptable/guideline
0, 200, 2000 or 20,000 ppm in diet
P1 males:  0, 15.4, 153.4 or 1551.9 mg/kg/day; 
P1 females:  0, 17.9, 180.7, 1820.7 mg/kg/day
Parental/Systemic NOAEL = 153.4/180.7 mg/kg/day [M/F];
LOAEL = 1551.9/1820.7 mg/kg/day [M/F] based on increased absolute and relative liver weights and microscopic midzonal to periportal hepatocellular hypertrophy.
Reproductive NOAEL = 1551.9/1820.7 mg/kg/day [M/F];
LOAEL > 1551.9/1820.7 mg/kg/day [M/F](HDT)
Offspring NOAEL =  mg/kg/day
LOAEL > 1551.9/1820.7 mg/kg/day [M/F](HDT)
870.4100a

Chronic toxicity
(rat)
See 870.4300
870.4100b

Chronic toxicity (dog)
44617728 (1997)
Acceptable/guideline
0, 60, 300, 3000 or 30,000 ppm in diet
M:  0, 2.2, 9.8, 106.1, 1152.4 mg/kg/day
F:  0, 2.2, 12.6, 110.6, 1199.2 mg/kg/day
NOAEL = 9.8/12.6 mg/kg/day [M/F]
LOAEL = 106.1/110.6 mg/kg/day [M/F] based on mild hematological changes (decreased RBC parameters, slight methemoglobinemia) and increased serum bilirubin.  Hematological effects first observed at week 14.
At 1152.4/1199.2 mg/kg/day:  bilirubinemia in males, increased abs/rel liver and thyroid weights, increased cellularity of sternum and rib marrow, increased pigmented macrophages in liver and spleen.
870.4200

Carcinogenicity
(rat)
44617731 (1998)
Acceptable/guideline
0, 200, 8000 or 20,000 ppm in diet
M:  0, 10.2, 411 or 1045 mg/kg/day
F:  0, 11.9, 491 or 1248 mg/kg/day
NOAEL = 10.2/11.9 mg/kg/day [M/F]
LOAEL = 411/491 mg/kg/day [M/F] based on hematological changes (decreased RBC parameters), periportal liver hypertrophy, thyroid hypertrophy and altered colloid; possibly increased adrenal weight.

At 1045/1248 mg/kg/day:  decreased survival in males, decreased body weight in females, increased abs/rel liver weight, chronic progressive glomerulonephropathy, tissue mineralization.

no evidence of carcinogenicity
870.4300

Carcinogenicity
(mouse)
44617729 (1998)
Acceptable/guideline
0, 70, 2800, 7000 ppm
M:  0, 10.0, 40.5 or 1020 mg/kg/day
F:  0, 12.8, 529 or 1354 mg/kg/day 

NOAEL =  1020/1354 mg/kg/day [M/F]
LOAEL >1020/1354 mg/kg/day [M/F](HDT)

no evidence of carcinogenicity
Gene Mutation
870. 5100 
Bacterial reverse gene mutation - Salmonella
44144428 (1995)
Acceptable/guideline
0, 50, 200, 500, 2000, 5000 ug/plate, initial assay; 0, 160, 300, 500, 900, 1600 ug/plate, repeat assay
No evidence of mutagenicity with or without S9 activation up to solubility limit (precipitation observed at >=900 ug/plate).
Gene Mutation
870.5100
Bacterial reverse gene mutation  - Salmonella 
44617733 (1998)
Acceptable/guideline
0, 50, 200, 500, 2000, 5000 ug/plate, test material:  RH-117,236 (Metabolite M-B)
No evidence of mutagenicity with or without S9 activation up to solubility limit (precipitation observed at 2000 and 5000 ug/plate)
In Vitro Mammalian Gene Mutation
870.5300
HGPRT forward gene mutation assay (Chinese hamster ovary, or CHO, cells)
44617734 (1994)
Acceptable/guideline
0, 0.1, 0.5, 1.0, 5.0, 10, 50, 100, 500, 1000, 1250 ug/mL (range-finding study);
0.5, 1.0, 5.0, 10, 50, 100 ug/mL (definitive study)
No evidence of mutagenicity with or without S9 activation up to solubility limit (precipitation observed at >=100 ug/mL).
In Vitro Cytogenetics 
870.5375 
Chromosomal aberration, CHO cells
44617735 (1994)
Acceptable/guideline
0, 0.21, 0.63, 2.1, 6.3, 21, 63, 108, 625, 1250 ug/mL (range-finding study);
0, 13, 125, 100, 150 ug/mL (definitive study)
No evidence of increased frequency of chromosomal aberration in the presence or absence of S9 activation up doses causing reduced mitotic indices (>=50 ug/mL).
Other Effects 
870.5395 
In vivo mouse micronucleus assay
44617801 (1995)
Acceptable/nonguideline
0, 500, 2500, 5000 mg/kg single IP dose
No evidence of increased frequency of micronucleus formation in treated CD-1mice in bone marrow at 24 or 48 hrs postdosing; tested up to the limit dose for this assay.
870.6200a

Acute neurotoxicity screening battery (rat)
44617802 (1996)
Acceptable/guideline
0, 1000, 2000 mg/kg by gavage
NOAEL = 1000 mg/kg (males); 2000 mg/kg (females; HDT)
LOAEL = 2000 mg/kg (males) based on decreased hindlimb grip strength on Day 0; >2000 mg/kg females (HDT)
870.6200b

Subchronic neurotoxicity screening battery (rat)
44617803 (1996)
Acceptable/guideline
0, 200, 2000 or 20,000 ppm in diet
Males 0, 13, 130, 1318 mg/kg/day
Females 0, 16, 159, 1577 mg/kg/day
NOAEL = 1318/1577 mg/kg/day [M/F]; LOAEL > 1318/1577 mg/kg/day [M/F] (HDT)
870.7485

Metabolism and pharmacokinetics
(rat)
44617804 (1998)
Acceptable/guideline
Single gavage doses of 10 mg/kg and 1000 mg/kg; 5-day repeated gavage doses of 10 mg/kg
Absorption and excretion were rapid (<48 hrs postdosing).  Tissue distribution was extensive but bioaccumulation was not observed.  Major route of excretion was via feces (86-97%) and to a lesser extent, the urine (5-13%).  Enterohepatic circulation was observed.  The primary routes of metabolism were O-demethylation and oxidative hydroxylation followed by conjugation with glucuronic acid.  
870.7600
Dermal penetration (rat)
44638202 (1998)
Acceptable/guideline

Mean dermal absorption at 10 and 24 hrs was 2% using an 80WP formulation.
870.7800
Immunotoxicity (female rat)
48592601 (2011)
Acceptable/guideline
0, 76.9, 324 or 1076 mg/kg/day in the diet (ppm not indicated)
Immunotoxicity NOAEL = 1076 mg/kg/day
Immunotoxicity LOAEL = not established
Systemic toxicity NOAEL = = 76.9 mg/kg/day
Systemic toxicity LOAEL = 324 mg/kg/day, based on increased liver weights.





A.3	Hazard Identification and Endpoint Selection

A.3.1	Acute Reference Dose (aRfD)  -  All Populations including Infants and Children and Females age 13-49

An acute reference dose for methoxyfenozide was not selected.  An appropriate toxicity dose and endpoint were not identified that could be attributed to a single exposure.  Decreased hindlimb grip strength in male rats in the acute neurotoxicity study was only observed at the limit dose of 2000 mg/kg on the day of dosing.

A.3.2	Chronic Reference Dose (cRfD) 

Study Selected: Chronic Feeding-Rat and Dog (co-critical studies)
MRID Nos.:  44617731 (rat) and 44617728 (dog)	
Executive Summaries:  See Appendix A, Guideline [§ 870.3150 (dog study) and 870.3500 (rat study)] 
Dose and Endpoint for Risk Assessment: NOAEL = 10.2 mg/kg/day (rat study), based on hematological changes (decreased RBC counts, hemoglobin concentrations, and/or hematocrit in males and females), liver effects (increased liver weights in males; periportal hepatocellular hypertrophy in males and females), histopathological changes in the thyroid (increased follicular cell hypertrophy, altered colloid in males) and possible adrenal toxicity (increased adrenal weights in males and females) seen at the LOAEL = 411 mg/kg/day.  Supported by the co-critical chronic dog NOAEL = 9.8 mg/kg/day, based on mild hematological changes (decreased RBC counts, hemoglobin concentrations and/or hematocrit in males and females; slight methemoglobinemia in males and females; increased platelets in males) and clinical chemistry changes (increased total serum bilirubin in males and females; slightly increased severity of bilirubinemia in males) seen at the LOAEL = 106 mg/kg/day.  
Comments about Study/Endpoint/Uncertainty Factors:  These studies were selected because they were of the appropriate duration (chronic) and route of exposure (dietary) and provided the most sensitive doses and endpoints.  They were selected as co-critical because of their similar NOAELs, both of which provide a cRfD of 0.10 mg/kg/day.  The selected dose is protective of potential hematological, hepatic and thyroid effects identified in two-week dietary studies in the rat and dog, which identified slightly higher NOAELs (see A.3.5, below), as well as potential developmental effects.  A combined UF of 100x was utilized (10X each to account for inter- and intra-species variability).   

A.3.3	Incidental Oral Exposure (Short- and Intermediate-Term)

An incidental oral exposure dose and endpoint were not selected.  Methoxyfenozide may be used on ornamental plants in a residential setting.  However, post-application incidental oral exposure is not expected since the extent to which young children engage in prolonged play or other activities involving such areas is low, and this assessment was not performed.  



A.3.4	Dermal Exposure (Short- and Intermediate-Term) 

A dose and endpoint for dermal exposure were not selected, based on the lack of toxicity in the rat dermal exposure study and a dermal absorption study demonstrating low (about 2%) absorption of methoxyfenozide in the 80WP formulation.  An oral study was not selected because the appropriate studies either showed no toxicity at any dose tested, or the parameters affected in oral studies (e.g., hematologic changes) were examined but showed no treatment-related changes in the dermal study.

A.3.5	Inhalation Exposure (Short- and Intermediate-Term) 

Study Selected:  Two-week range-finding study for the subchronic dietary study in the dog
MRID No.:  44617722
Executive Summary:  See Appendix A, Guideline [§ 870.3150] 
Dose and Endpoint for Risk Assessment: NOAEL = 16.8 mg/kg/day, based on hematological changes seen at LOAEL = 90.8 mg/kg/day.  
Comments about Study/Endpoint/Uncertainty Factors:  No short-term or subchronic inhalation toxicity studies were available; an oral study was therefore selected for route-to-route extrapolation.  The dog 2-week dietary range-finding study was selected because it is of an appropriate duration and it identified the most sensitive dose and endpoint for this exposure scenario. Findings included hematological effects (including decreased RBC counts, decreased hemoglobin concentrations, Heinz bodies and changes in RBC morphology, increased reticulocyte counts and methemoglobinemia).  The range-finding study was selected in lieu of the 90-day subchronic dog study because no effects were reported at doses up to about 200 mg/kg/day.  However, in the chronic dog study, mild hematological changes were reported at 14 weeks at the LOAEL of 106 mg/kg/day, with a NOAEL of 9.8 mg/kg/day.  The reason for the early effects is unclear, but it may reflect adaptation of the animals to the test material.  A similar circumstance was observed with the rat two-week and 90-day dietary studies:  thyroid and adrenal effects were observed at lower dose levels in the two-week study (1000 ppm, or estimated 69 mg/kg/day with a NOAEL of 250 ppm or 17 mg/kg/day) whereas the subchronic NOAEL was 1000 ppm with a LOAEL of 5000 ppm or 353 mg/kg/day), based on liver weight increases and hypertrophy.  Decreased body weight was observed in the subchronic mouse dietary study, but no effects were seen in the 18-month carcinogenicity study.

Because only two animals/sex/dose were in each dose group, the NOAEL and LOAEL for this risk assessment were selected from the highest NOAEL and lowest LOAEL from individual animals' average daily compound intake.  The selected dose and endpoint are considered to be conservative endpoints that provide protection from potential hematological effects, which may be transient at the selected study LOAEL, based on the lack of effects in the subchronic dog study.  The study is protective of potential developmental effects, because no developmental or offspring toxicity was observed in any of the available developmental and reproductive toxicity studies.  Although a repeated-dose inhalation toxicity study is not available, the oral study is considered adequately protective, based on the conservative endpoint selected, low vapor pressure of methoxyfenozide, low application rate for current use patterns, and low acute inhalation toxicity; a 10X UFDB is therefore not required.  A combined UF of 100x was utilized (10X each to account for inter- and intra-species variability). 
A.4	Executive Summaries

A.4.1	Subchronic Toxicity

	870.3100	90-Day Oral Toxicity - Rat

In a subchronic oral toxicity study (MRID No. 44617722), methoxyfenozide technical (99.2% purity, Lot No. WS-10395, TD No. 92-014) was administered by dietary admix to Charles River Crl:CD BR rats (10/sex/group) at doses of 0, 50, 250, 1000, 5000 or 20,000 (limit dose) ppm (equivalent to average daily intakes of 0, 3.4, 17.0, 69.3, 353.4 or 1368.8 mg/kg/day in males and  0,3.7, 19.1, 72.4, 379.3 and 1,531.2 mg/kg/day in females) for 13 weeks. The following parameters were examined: mortality, clinical signs, body weights, food consumption, ophthalmology, hematology, clinical chemistry, urinalysis, organ weights, macroscopic pathology and microscopic pathology.

The following effects were observed: a statistically significant reduction in red blood cells and hemoglobin in 20,000 ppm females (7-8% less than controls) and slight or moderate periportal hepatocellular hypertrophy in all 5000 and 20,000 ppm males and females compared with none observed in controls or lower dose rats. There were statistically significant increases in relative-to-body weight liver weights in 5000 and 20,000 ppm males as well as in 20,000 ppm females (11-16% above controls). There were increases in absolute liver weights in both sexes at 5000 and 20,000 ppm when compared to controls (+7 to 13% in males and +9 to 10% in females), however these increases were not statistically significant.  

[It is noted that in the 2-week range-finding study, which tested at 0, 50, 250, 1000, 5000 and 20,000 ppm, some effects were observed which were not observed in the 13-week study, and these findings were seen at a lower dose than the LOAEL for the subchronic study.  At 1000 ppm, follicular cell thyroid follicular cell hypertrophy/hyperplasia in 3/5 males and 2/5 females, and minimal hypertrophy of the adrenal gland zona fasciculata in 1/5 female (all vs. 0/5 controls) were observed; these effects were also seen at higher doses.  At >=5000 ppm, liver absolute and relative weights in males, adrenal absolute and relative weights in females, and hepatocellular hypertrophy in females were also increased.  Necrosis of hepatocytes was observed in males at 20,000 ppm.]  

The LOAEL (subchronic study only) is 5000 ppm (353.4/379.3 mg/kg/day, males/females), based on effects on the liver (increased absolute and relative weights, and periportal hepatocellular hypertrophy in both sexes).  The NOAEL is 1000 ppm (69.3/72.4 mg/kg/day in males/females).

This study is classified Acceptable/guideline and satisfies the data requirement for OPPTS §870.3100 for a three-month oral toxicity study in rats.

	870.3100	90-Day Oral Toxicity - Mouse

In a. subchronic toxicity study (MRID No. 44617723), methoxyfenozide technical (99.2% purity, Lot No. WS-10395, TD No. 92-014) was administered by dietary admix to Charles River Crl:CD-1 (ICR) BR VAF/+ mice (10/sex/group) at doses of 0, 70, 700, 2500 or 7000 ppm (equivalent to average daily intakes of 0, 11.9, 112.5, 428.2 or 1149.3 mg/kg/day in males and 0, 17.4, 165.1, 589.4 and 1742.1 mg/kg/day in females) for 13 weeks. The following parameters were examined: mortality, clinical signs, body weights, feed consumption, hematology, clinical chemistry, organ weights, macroscopic pathology and microscopic pathology.

There were no clinical signs and all mice survived until scheduled sacrifice. Body weight gains in the 7,000 ppm group were less than respective controls for males (18%) and females (15%) for the 13-week period. Food consumption did not appear to be altered. There were no apparent effects on the following parameters: hematology, clinical chemistry, organ weights, macroscopic pathology or microscopic pathology.

The LOAEL is 7000 ppm (1149.3/1742.1 mg/kg/day in males/females; limit dose), based on a decrease in body weight gain in males and females.  The NOAEL is 2500 ppm (428.2/589.4 mg/kg/day in males/females).  

This study is classified acceptable/guideline and satisfies the data requirement for a subchronic oral toxicity study in the mouse (OPPTS §870.3100).

	870.3150	90-Day Oral Toxicity - Dog

In a subchronic toxicity study (MRID No.44617724), methoxyfenozide technical (99.8% purity, Lot No. WS-10395, TD No. 92-014) was administered by dietary admix to Hazleton Research Products beagle dogs (4/sex/group) at doses of 0, 15, 50, 500 or 5000 ppm (equivalent to average daily intakes of 0, 0.6, 2.0, 21.4 or 197.5 mg/kg/day in males and 0, 0.6, 1.9, 20.4 or 208.8 mg/kg/day in females) for 13 weeks. The 15 ppm group was then dosed for an additional 2 weeks at 15 ppm, followed by an increase in dose to 15,000 ppm for another 6 weeks. The doses in mg/kg/day for the additional 6 weeks were 422.0 mg/kg/day for males and 460.4 mg/kg/day for females. No control animals were kept beyond the original 13 weeks for comparison with these higher dose levels.  The following parameters were examined:  mortality, clinical signs, ophthalmology, body weights, feed consumption, hematology, clinical chemistry, urinalysis, organ weights, macroscopic pathology and microscopic pathology.

There was the suggestion (no statistical significance) that 5000 ppm caused a decrease in body weight gain in both sexes over the 13-week period (males: controls = 3.7 kg, 5000 ppm 3.3 kg; females: controls = 3.0 kg, 5000 ppm = 2.4 kg).  However, these differences were not considered sufficient to establish an adverse effect.  All dogs treated with 15,000 ppm for the 6 additional weeks gained weight. However, there was no additional control group with which to compare the results.  No other parameters were affected by test article administration.

[Results of a two week range-finding study were also provided in this report, which dosed 2 dogs/sex/group at 0, 300, 3500, 7000, 15,000 or 30,000 ppm (equivalent to individual animal intakes of 0, 11.7-14.7, 141.6-167.6, 264.7-370.4, 571.4-631.7 or 1113.7-1337.0 mg/kg/day for males and 0, 13.3-16.8, 90.8-184.8, 285.9-336.8, 582.3-630.9 or 1092.6-1169.1 mg/kg/day for females).  Although there were no clear-cut definitive effects on any hematology parameters in the 13-week study, in the 2-week range-finding study, there were decreases for all animals of both sexes in RBC count (13-20%), hemoglobin (9-18%) and hematocrit (8-16%) for all animals of both sexes at >=3500 ppm after two weeks when compared with the pre-dose values.  Methemoglobinemia and abnormal RBC morphology (Heinz bodies, Howell-Jolly bodies, polychromasia) were reported as well.  Increased spleen weights were also observed at >=3500 ppm.  Bilirubinemia was observed at >=7000 ppm in males.  No effects were identified in the range-finding study at 300 ppm.  

The NOAEL (subchronic study only) is 5000 ppm (197.5/208.8 mg/kg/day, males/females; HDT).  A LOAEL was not determined (>5000 ppm).  

This study is classified acceptable/guideline and satisfies the data requirement for a three-month toxicity study in dogs (OPPTS §870.3150).  Although a LOAEL was not achieved, toxicity was observed in a two-week range-finding study and an acceptable chronic dog toxicity study is available (MRID 44617728).

	870.3200	28-Day Dermal Toxicity  -  Rat

In a 28-day repeated dose dermal toxicity study (MRID 44617725), groups of 10 male and 10 female Crl:CD(R)BR rats were treated with RH-2485 Technical (98%, Lot No. 1), by dermal application to shaved skin moistened with tap water and held in place by dermal occlusion, at doses of 0, 75, 300, or 1000 mg/kg/day for 6 hours/day, 5 days/week. 

No mortality was recorded, and there were no clinical signs indicative of systemic toxicity at any treatment level. No treatment-related dermal irritation was produced. Additionally, there were no treatment-related effects on body weight, food consumption, absolute or relative organ weight, hematology, or clinical chemistry in either sex of rats. No gross or microscopic changes in either sex were found to be caused by the treatments.

The systemic NOAEL is 1000 mg/kg/day (HDT).  The systemic LOAEL was not determined for either male or female rats (>1000 mg/kg/day). The dermal NOAEL was 1000 mg/kg/day.  The dermal LOAEL was not established (>1000 mg/kg/day).

This study is classified as Acceptable/guideline and satisfies the guideline requirement for a 28-day dermal study in rats (OPPTS §870.3200). Although a LOAEL was not established, the highest dose tested (1000 mg/kg) is the limit dose.

	870.3465	90-Day Inhalation  -  Rat

Not required and not submitted

A.4.2	Prenatal Developmental Toxicity

	870.3700a Prenatal Developmental Toxicity Study - Rat

In a developmental toxicity study (MRID No. 44638201), methoxyfenozide technical (99.2% purity) was administered by gavage to Charles River Crl:CD BR VAF/Plus (Sprague-Dawley) rats (25/group) at doses of 0 (0.5% aqueous methylcellulose vehicle), 100, 300 or 1,000 mg/kg/day on gestation days 6 through 15.  The following parameters were examined: maternal (clinical signs, morbidity, mortality, body weights, food consumption, corpora lutea, implantation sites, resorption sites, abdominal/thoracic cavities and the position of live/dead fetuses) and fetuses (weights, external changes, Bouin's soft tissue examination and skeletal changes).

Maternal toxicity:  There were no deaths or clinical signs, nor where there any effects on body weights or food consumption.  No changes were noted in any of the reproductive parameters.  The maternal NOAEL is 1,000 mg/kg/day (HDT, limit dose).  A maternal LOAEL was not determined (>1,000 mg/kg/day).
      
Developmental toxicity:  Fetal examinations did not reveal any affects on body weight or gross/visceral/skeletal aspects.  The developmental NOAEL is 1,000 mg/kg/day.  A developmental LOAEL was not determined (>1,000 mg/kg/day).

This study is classified Acceptable/guideline and satisfies the guideline criteria for a developmental toxicity study in the rat (OPPTS §870.3700a).

	870.3700b Prenatal Developmental Toxicity Study - Rabbit

In a developmental toxicity study (MRID No. 44617726), methoxyfenozide technical (98.0% purity) was administered by gavage to Hazleton Research Products New Zealand White rabbits (16/group) at doses of 0 (0.5% aqueous methylcellulose vehicle), 100, 300 or 1,000 mg/kg/day on gestation days 7 through 19.  The following parameters were examined: maternal (clinical signs, morbidity, mortality, body weights, food consumption, corpora lutea, implantation sites, resorption sites, abdominal/thoracic cavities and the position of live/dead fetuses) and fetuses (weights, external changes, soft tissue examination, brain, eyes and skeletal changes).

Maternal toxicity:  There were no deaths or clinical signs, nor where there any effects on body weights or food consumption.  No changes were noted in any of the reproductive parameters.  The maternal NOAEL is 1,000 mg/kg/day (HDT, limit dose).  A maternal LOAEL was not determined (>1,000 mg/kg/day).
      
Developmental toxicity:  Fetal examinations did not reveal any affects on body weight or gross/visceral/skeletal aspects.  The developmental NOAEL is 1,000 mg/kg/day.  A developmental LOAEL was not determined (>1,000 mg/kg/day).
      
This study is classified Acceptable/guideline and satisfies the guideline criteria for a developmental toxicity study in the rabbit (OPPTS §870.3700b).

A.4.3	Reproductive Toxicity

	870.3800 Reproduction and Fertility Effects - Rat

In a two-generation reproduction study (MRID 44617727), RH-2485 Technical  (98.0% a.i.) was administered to 30 Crl:CD(R)BR rats/sex/dose in the diet at concentrations of 0, 200, 2000, or 20,000 ppm (equivalent to average daily intake for P1 males of 0, 15.4, 153.4, or 1551.9 mg/kg/day, respectively; for P1 females of 0, 17.9, 180.7, or 1820.7 mg/kg/day, respectively; for P2 males of 0, 19.1, 193.1, or 1956.0 mg/kg/day, respectively; and for P2 females of 0, 20.4, 202.7, or 2036.5 mg/kg/day, respectively).  Treatment was continuous throughout the study.  The two parental generations, P1 and P2, produced one litter of pups each (F1 and F2, respectively).  The parental animals received the test diet for 10 weeks before mating and throughout mating, pregnancy, and lactation of their litters.  Pups were selected from the F1 litters to parent the F2 generation.  The P1 generation produced 22 to 27 litters/group consisting of liveborn pups, the P2 generation produced 24 to 28 liveborn litters/group.

Parental toxicity:   In this study, the target organ for the systemic toxicity of RH-2485 Technical to adult rats was the liver.  For the P1 and P2 males and females exposed to 20,000 ppm, the absolute and relative terminal liver weights were significantly increased by 13 to 27% (p<0.05), in comparison to control values.  Microscopic changes in the liver included midzonal to periportal hepatocellular hypertrophy in all of the animals of both generations at 20,000 ppm, and in females, only, at 2000 ppm.   The incidence rates for hepatocellular hypertrophy at 0, 200, 2,000 and 20,000 ppm were as follows: 0/30, 0/30, 0/30, and 30/30 (100%), respectively, for the P1 and P2 males:  0/30, 0/30, 4/30 (13.3%) and 30/30 (100%), respectively, for the P1 females; and 0/30, 0/30, 1/30 (3.3%), and 30/30 (100%), respectively, for the P2 females.

Statistically significant reductions (p<0.05) in body weights and cumulative body weight gains were observed among the high-dose P1 males during the last 12 weeks of the study; however, the reductions were never more than 7% ( p<0.05), in comparison to control values; the overall body weight gain (weeks 0-20) for this group was depressed by 10% (p<0.05).  Body weights, food consumption, and body-weight gains were comparable to, or significantly higher than, control values for the P2 males throughout the study and for the P1 and P2 females during premating, gestation, and lactation.  Therefore, the biological significance of the reduced body weights of the P1 males is questionable.
      
The following parameters of systemic toxicity were comparable for RH-2485 Technical-treated and control P1 and P2 males and females: mortality, clinical signs, gross pathology, relative and absolute terminal weights of the reproductive organs, and microscopic pathology of the reproductive organs.  The LOAEL for parental toxicity is 20,000 ppm (1551.9 mg/kg/day), based on increased absolute and relative liver weights in males and females and on hepatocellular hypertrophy in males and females.  The NOAEL for parental toxicity is 2000 ppm (153.4 mg/kg/day).

Offspring toxicity:  Treated F1 and F2 litters were comparable to control litters with regard to macroscopic abnormalities, malformations, or variations; number of liveborn pups (total and per litter); number of live pups/litter on days 4, 7, 14, or 21 of lactation; the number of stillborn pups (total and per litter); body weights on days 0, 4, 7, 14, and 21 of lactation; sexual maturity; sex ratios; anogenital distance; and indices of survival.  The NOAEL for offspring toxicity is 20,000 ppm (1551.9 mg/kg/day; HDT).  A LOAEL for offspring toxicity was not established (>20,000 ppm).

Reproductive toxicity:  There were no treatment-related reproductive effects on the P1 and P2 males and females or their F1 and F2 offspring.  The endpoints of reproductive function and performance for P1 and P2 parental generations were comparable for RH-2485 Technical-treated and control animals with regard to the following:  length and periodicity of the estrous cycle; copulatory interval; number of females inseminated and/or pregnant; length of gestation; sperm motility, morphology, and concentration; and indices of mating, fertility, and gestation.  The NOAEL for reproductive toxicity is >20,000 ppm (1551.9 mg/kg/day).  The LOAEL for reproductive toxicity was not identified (>20,000 ppm).
      
This study is classified Acceptable/guideline and satisfies the guideline criteria for a reproductive toxicity study in the rat (OPPTS §870.3800).
A.4.4	Chronic Toxicity

	870.4100a (870.4300) Chronic Toxicity  -  Rat

See 870.4300, below

	870.4100b Chronic Toxicity - Dog

In a chronic oral toxicity study (MRID 44617728), RH-2486 technical (methoxyfenozide, 98.9% a.i., Lot No. 1, TD94-134) was administered in the diet to 4 beagle dogs/sex/dose at dietary concentrations of 0, 60, 300, 3000 or 30,000 ppm for 52 weeks (equivalent to average daily intakes of 0, 2.2, 9.8, 106.1 or 1152.4 mg/kg/day in males and 0, 2.2, 12.6, 110.6 or 1199.2 mg/kg/day in females).

The most notable compound-related hematologic effects consisted of methemoglobinemia, nucleated red blood cells (RBCs) and mild hemolysis, particularly in females.  At 3000 ppm, mild hematological effects were observed by 14 weeks of treatment.  Methemoglobinemia was observed in males (increased to 157-167% of controls) and females (153-183% of controls) at most or all time points.  In males, platelets were significantly increased (156-163%) at all time points and RBCs were significantly decreased at week 14.  Hct, Hg and RBCs were generally decreased in females throughout the study (13-18%), but only occasionally achieved statistical significance.  No overt clinical signs of treatment-related toxicity were observed, and survival, body weights, body weight gains and food consumption were also unaffected by compound administration.

At 30,000 ppm, hematological effects were more pronounced and increased cellularity of the rib and sternum marrow were observed in 1-2 males and females.  Absolute and relative liver weight were slightly increased (10-24%), but only absolute weight in males was statistically significant (24% above controls).  An increase in pigmented macrophages was observed in the liver and spleen in 1-3 animals in both sexes.  Absolute and relative thyroid weights were increased (144%/163%), but there was no corresponding histopathology.  Bilirubinemia in males was also observed.

The LOAEL is 3000 ppm (106.1/110.6 mg/kg/day in males/females), based on hematological effects including mild anemia and methemoglobinemia.  The NOAEL is 300 ppm (9.8/12.6 mg/kg/day in males/females).

This study is classified Acceptable/guideline and satisfies the guideline criteria for a chronic oral toxicity study in the dog (OPPTS §870.4100b).

A.4.5	Carcinogenicity

	870.4200a Carcinogenicity Study - rat

See 870.4300, below

	870.4200b Carcinogenicity (feeding)  -  Mouse

In a carcinogenicity feeding study (MRID 44617729), RH-2485 (98.0% a.i.; Sample No. 94-134, Lot No. 1) was administered to 60 Crl:CD-1 (ICR) BR (VAF/+) mice/sex/dose in the diet at concentrations of 0, 70, 2800 or 7000 ppm for 18 months (intake for males: 0, 10.0, 405, or 1020 mg/kg/day; for females: 0, 12.8, 529, or 1354 mg/kg/day).

No toxicologically significant differences were found between the treated and control animals of either sex.  Clinical signs, survival, body weight, and food consumption were comparable in treated and control animals.  The lower lymphocyte count and alterations in kidney and testes weights in males were small in magnitude ( 16%, p < 0.05), not dose-related, and/or lacked histopathological correlates.  There were no treatment-related gross or microscopic lesions.

The NOAEL is 7000 ppm (1020/1354 mg/kg/day for males/females)(HDT). A LOAEL was not established in this study (> 7000 ppm).

There was no evidence of carcinogenicity in male or female mice.  The incidence of neoplasms found in numerous organs and tissues was comparable in treated and control groups.  The animals were dosed adequately since their intake exceeded the limit dose of 1000 mg/kg/day.

Discussion of Tumor Data:  There was no evidence of carcinogenicity in this study. 
 
Adequacy of the Dose Levels Tested:  In this study, methoxyfenozide was administered at adequate dose levels for carcinogenicity testing since it was tested at the limit dose of 7000 ppm (1020 mg/kg/day in males and 1354 mg/kg/day in females).     

This study is classified Acceptable/guideline and satisfies the guideline requirement for a dietary carcinogenicity study in the mouse (OPPTS §870.4200b)

	870.4300 Chronic toxicity/carcinogenicity (feeding)  -  Rat

In a combined chronic toxicity /carcinogenicity study (MRID 44617731), RH-2485 technical (methoxyfenozide 98% a.i.; Lot Number 1, TD94-134) was administered in the diet to 70 male and 70 female Crl:CD[(R)]BR rats per group at concentrations of 0, 200, 8000, or 20,000 ppm (0, 10.2, 411, or 1045 mg/kg/day for males and 0, 11.9, 491, or 1248 mg/kg/day for females) for up to 99 weeks in males (only 89 weeks in the 20,000-ppm group) and 95 weeks in females except for 10 animals per sex per dose that were sacrificed at 52 weeks for interim evaluation. 
 
Survival was adversely affected in males at the 20,000-ppm dose level.  Survival rates to week 89 in the 0 and 20,000-ppm groups in the main experiment on males were 28/60 (53% dead) and 17/60 (72% dead), respectively, with this difference being significant, p<0.05 as calculated by reviewer.  The only significant (p<0.05) effects on absolute body weight, body-weight gain, and food efficiency were in the 20,000-ppm females.  In approximately the last year of the experi - ment, reductions in absolute body weight were often to a level of slightly less than 90% that of the control.  At the end of the experiment, absolute body weight was reduced 17% in females.  Reductions in body-weight gain were often to a level of about 80% of the control.  Reductions in food efficiency were about 11% and 49% in the first and second years, respectively.

Treatment-related and significant (p<0.05) hematology changes at the two higher doses consisted of small reductions (less than 10% compared to control) in RBC counts, hemoglobin concentrations, and/or hematocrit, and these effects were seen in both sexes.  At the highest dose, there were significant (p<0.05) increases in methemoglobin over the control in both sexes, and there was a significant (p<0.05) increase in platelet counts over control in females.  Clinical chemistry evaluations in both sexes at the two higher doses showed significant (p<0.05) and probably treatment-related increases in serum levels of gamma glutamyl transpeptidase (GGT) and reductions in total bilirubin in the serum.  These two effects on clinical chemistry are of uncertain, and probably unlikely, biological significance.

The liver, kidneys and thyroid were identified as targets for RH-2485 Technical toxicity.  Significant increases (p<0.05) were found in absolute and relative liver weights compared to control in both sexes at the 20,000 ppm dose.  These ranged up to 23% increase in males and 24% increase in females at the terminal sacrifice.  At the 8000 ppm dose in males at 52 weeks, a significant increase (p<0.05) was found in relative liver weight (19%) and a non-significant increase was found in absolute liver weight (21%).  These changes are consistent with the finding of much increased and significant (p<0.01) incidences of periportal hepatocellular hypertrophy in both sexes at both the 8000- and 20,000-ppm doses.  At the terminal sacrifice, the incidences of this lesion in control males and females were 2% and 3%, respectively.   [Here and below in this paragraph, percents refer to all animals in the main study.]  In contrast, in males of the 8000- and 20,000-ppm groups, the incidences were 35% and 53%, respectively.  In females of these same groups at the terminal sacrifice, the incidences were 40% and 70%, respectively.  An increase in the incidence of the more serious manifestations of chronic progressive glomerulonephropathy is thought to have increased the mortality rate of males fed 20,000-ppm of the test substance.  Microscopic analysis demonstrated two treatment-related lesions in the thyroid at the terminal sacrifice: 1) follicular cell hypertrophy in 8000-ppm males (25%, not significant) and 20,000-ppm males (31%, p<0.05) compared with 13% in controls; 2)  altered colloid in 8000 ppm males (22%, not significant) and 20,000 ppm males (24%, not significant) compared with 12% in controls as well as in 20,000-ppm females (38%, p<0.01) compared with 17% in controls.  Increases were found at the terminal sacrifice for absolute and relative weights of adrenal glands compared to controls in 20,000-ppm males (up to 25%, not significant) and in 20,000 ppm females (up to 100%, p<0.05 for relative weight).  Similar increases were found at the terminal sacrifice for absolute and relative weights of adrenal glands compared to controls in 8000-ppm males (up to 55%, not significant) and in 8000 ppm females (up to 31%, not significant).  Numerous other treatment-related microscopic lesions were identified only in 20,000-ppm females (mainly mineralizations of tissues found in from 7­13% of the animals); these were considered secondary changes attributable to uremia that resulted from the chronic progressive glomerulonephropathy.  No effects attributable to the test material were observed at 200 ppm.  The LOAEL is 8000 ppm (411 mg/kg/day for males and 491 mg/kg/day for females), based on hematological changes (decreased RBC counts, hemoglobin concentrations, and/or hematocrit in males and females), liver toxicity (increased liver weights in males and periportal hepatocellular hypertrophy in males and females), histopathological changes in the thyroid (increased follicular hypertrophy and altered colloid in males) and possible adrenal toxicity (increased adrenal weights in males and females).  The absence of treatment-related effects identifies a NOAEL of 200 ppm (10.2 mg/kg/day for males and 11.9 mg/kg/day for females).
 
No evidence of carcinogenicity was observed in rats fed RH-2485 Technical at dietary concentrations of 200, 8000, or 20,000 ppm for up to 99 weeks.  Dosing was considered adequate because of the decreases in body weights, body-weight gain, and food efficiency in female rats fed the 20,000-ppm diet and because of the decrease in survival in male rats fed the 20,000-ppm diet.  The highest dose tested for both males and females is also higher than the limit dose of 1000 mg/kg/day.

This study is classified Acceptable/guideline and satisfies the guideline requirement for a dietary carcinogenicity study in the rat (OPPTS §870.4200a)

A.4.6	Mutagenicity

	Gene Mutation
870.5100 Bacterial reverse gene mutation assay (S. typhimurium strains TA 98, TA100, TA1535, TA1537
MRID 44617728
Acceptable/guideline
Dose range 
Negative for gene mutation up to insoluble  concentrations (precipitation observed at >=2000 ug/plate) in the presence or absence of S9 metabolic activation
870.5100 Bacterial reverse gene mutation assay (S. typhimurium strains TA 98, TA100, TA1535, TA1537
MRID 44617733
Acceptable/guideline
Dose range 50 to 5000 ug/plate, test material RH-117,236 (metabolite of methoxyfenozide)
Negative for gene mutation up to insoluble concentrations (precipitation observed at 5000 ug/plate) in the presence or absence of S9 metabolic activation.
870.5300 Mammalian in vitro cell forward gene mutation assay (CHO cells)
MRID 44617734
Acceptable/guideline
Dose range 0.1 to 1250 ug/mL.
Negative for gene mutation up to insoluble concentrations (precipitation observed at >=100 ug/mL) in the presence or absence of S9 metabolic activation.



	Cytogenetics
870.5375, Mammalian in vitro chromosomal aberration assay (CHO cells)
MRID 44617735
Acceptable/guideline
Dose range 0.21 to 1250 ug/mL.
Negative for increased frequency of chromosomal aberration, up to concentrations (>=50 ug/mL) at which the mitotic indices were decreased, in the presence or absence of S9 metabolic activation.

	Other Genotoxicity
870.5395, Mouse micronucleus assay
MRID 44617801
Acceptable/guideline
Dose range 500 to 5000 mg/kg (single IP dose).
Negative for increased frequency of micronucleus formation in CD-1 mice at 24 or 48 hrs postdosing up to the limit dose for this assay.

A.4.7	Neurotoxicity

	870.6100 Delayed Neurotoxicity Study - Hen

Not required and not submitted

	870.6200 Acute Neurotoxicity Screening Battery


In an acute oral neurotoxicity study (MRID 44617802), groups of 10 Crl:CD(R)BR  rats/sex/group were administered single gavage doses of RH-2485 technical (Toxicology Department Sample Number 94-134; Lot No. 1; 98 % active ingredient) at 0 (control), 500, 1000, or 2000 mg a.i./kg. The active ingredient was suspended in 0.5% aqueous methylcellulose and administered at a constant volume of 20 ml/kg. Functional observational battery (FOB) and motor activity (MA) testing were performed prior to administration and within 3 hours (time of peak effect) of dosing (day 0), and on days 7 and 14 post-dose.  Body weights were recorded pre-test, weekly during the study period and on FOB assessment days. Clinical signs were recorded daily. At necropsy all rats were perfused in situ and given a limited gross necropsy; six rats/sex/dose (high-dose and control) were further processed for neuropathological evaluation at study termination.

All animals survived to scheduled termination.  Daily cage-side observations revealed no overt signs of treatment-related effects in males or females at any exposure concentration.  No treatment-related effects on body weight were observed during the study.

There were no observable signs of a neurotoxic effect even at the highest concentration in females.  FOB assessment on Day 0 (3 hours after dosing) revealed a decrease in hindlimb grip strength (% below controls) for males in the 2000 mg/kg group. MA assessment remained comparable to controls throughout the study for males and females in all exposure groups.
 
No neuropathological endpoints were observed during the histological examinations of the peripheral or central nervous systems of these animals at any exposure concentration.

Based on the absence of any substance-related effects on body weight or body weight gain and any clinical signs of toxicity, the NOAEL for systemic toxicity is a concentration of 2000 mg/kg for males and females. The NOAEL for neurotoxic effects is 2000 mg/kg for females. Based on a decrease in hindlimb grip strength on day 0 in the 2000 mg/kg male group, the NOAEL for males is 1000 mg/kg and the LOAEL for males is 2000 mg/kg. No LOAEL was established for systemic effects in males or females or for neurotoxic effects in females. 
      
This study is classified as Acceptable/guideline and satisfies the guideline requirement for an acute oral neurotoxicity screening study in the rat (OPPTS §870.6200a).

	870.6200 Subchronic Neurotoxicity Screening Battery

In a subchronic oral neurotoxicity study (MRID 44617803), groups of Crl:CD(R)BR rats (10 rats/sex/group) were administered concentrations of 0, 200, 2000 or 20,000 ppm of RH-2485 technical (Toxicology Department Sample Number 94-0134; Lot No. 1; 98 % active ingredient) in the diet for 3 months. These doses resulted in average daily intake values of 0, 13, 130, and 1318 mg/kg/day for males and 0, 16, 159, and 1577 mg/kg/day in females for 0, 200, 2000, and 20,000 ppm, respectively. Functional observational battery (FOB) and motor activity (MA) testing were performed prior to administration and in the 4[th], 8[th], and 13[th] week of the administration period.  Body weights were recorded pre-test, weekly during the study period and on FOB assessment days. Food consumption was determined weekly for each animal. All rats surviving to necropsy were perfused in situ and given a limited gross necropsy. Six/rats/sex/dose (high-dose and control) were further processed for neuropathological evaluation at study termination.

One male in the 20,000 ppm group was found dead during week 5 of the study; this death was attributed to a urethral obstruction and was not considered to be treatment-related. All animals in all other exposure groups survived to scheduled termination.

Daily cage-side observations and weekly physical examinations revealed no overt signs of treatment-related effects in males or females at any exposure concentration. No treatment-related effects on body weight, body weight gain, or food consumption were observed during the study.

There were no observable signs of a neurotoxic effect even at the highest concentration in males or females.  FOB and MA remained comparable to controls throughout the study and no neuropathological endpoints were observed during the histological examinations of these animals at any exposure concentration.

Based on the absence of any substance-related effects on body weight or body weight gain and any clinical signs of toxicity, the NOAEL for systemic toxicity is 20,000 ppm for males (1318 mg/kg/day) and females (1577 mg/kg/day). The NOAEL for neurotoxic effects is 20,000 ppm (1318/1577 mg/kg/day in males/females).  A LOAEL was not established for either systemic or neurotoxic effects (>20,000 ppm). 

This study is classified as Acceptable/guideline and satisfies the guideline requirement for a subchronic oral neurobehavioral screening study in the rat (§870.6200b).

	870.6300 Developmental Neurotoxicity Study

Not required and not submitted

A.4.8	Metabolism

	870.7485	Metabolism  -  Rat

In an oral metabolism study (MRID 44617804), groups of five Crl:CD(R)BR rats/sex/dose group received methoxyfenozide (technical grade, several lots labeled at different positions with radiochemical purity ranging from 96.4 to 99.0%) according to the following schedules:  a single low dose (10 mg/kg labeled with [14] C at the t-butyl, A-ring or B-ring); high dose (1000 mg/kg labeled at the t-butyl or A-ring); or diets containing 10 mg/kg unlabeled test material for two weeks, followed by a single 10 mg/kg gavage dose of test material labeled on the A-ring.  Other groups of 3-6 male and 3-6 female rats received five daily doses of 10 mg/kg test material labeled on the A-ring or a single low- or high-dose of test material labeled at the t-butyl or A-ring to determine pharmacokinetics and tissue distribution. One additional group of 4 male and 4 female cannulated rats received a single low-dose of test material labeled on the A-ring to determine biliary excretion. In a preliminary study, expired air was collected from male and female rats that received 1000 mg/kg test material labeled at the t-butyl, A-ring, or B-ring positions. It was found that < 0.1% of the administered dose was removed in this manner and no further expired air studies were done.

No test material-related deaths occurred and mass balance, ranging from 93-104%, was acceptable. The total plasma elimination rate for male and female rats was longer for high dose relative to low dose animals; suggestive of metabolic pathway saturation. This particular effect was more prominent with female rats, regardless of label position. Following absorption, the test
material was rapidly metabolized and excreted. The highest radiolabel tissue concentrations at Cmax (0.25 hours post-treatment) were found in the intestinal tract, stomach, and liver, respectively, although at Cmax the liver contained <9% of the administered dose. By 1/2 Cmax, (1-2 hours post-treatment), radiolabel concentrations in the stomach and liver had decreased to <3% of the dose but remained relatively constant in the intestinal tract. Male and female cannulated rats excreted 62-70% of the administered dose into the bile and urine, indicating that absorption would at least be equivalent. By five days after treatment, the highest concentrations of radioactivity were found in the liver (<0.2% of dose) and carcass (<0.1% of dose) with <0.01% of the dose in other tissues and organs. No apparent effects attributable to label position or sex were noted.

The test material was excreted primarily into the feces with approximately 86-97% of a 10 mg/kg or 1000 mg/kg dose eliminated by this route. Urinary excretion was relatively minor and accounted for 5-13% of the administered dose. No substantial quantitative differences in the urine and fecal excretion profiles for the different radiolabel positions were observed. 

Elimination of the radiolabel by all treatment groups and both sexes was essentially complete within 48 hours of treatment.

Before excretion, the test material was metabolized principally by O-demethylation and oxidative hydroxylation on the A-ring phenyl and/or B-ring methyl groups followed by glucuronic acid or sulfate conjugation. Cleavage of the amide linkage from either the A-ring or B-ring side and conjugation with glycine to form the corresponding substituted hippuric acid metabolite was a minor route. No significant sex-related differences in the metabolic disposition of the test material were noted, although there were some minor sex-related differences. No significant dose-dependent differences in metabolic disposition were found.

This metabolism study in the rat is classified as Acceptable/guideline and satisfies the guideline requirement for a general metabolism study (OPPTS §870.7485) in the rat.

	870.7600	Dermal Absorption - Rat

In an in vivo dermal penetration study (MRID 44638202), four male rats per experimental group were dosed by dermal application to shaved skin of methoxyfenozide as either the a-ring labeled [14]C-RH-1 12,485 80WP (80% a.i.) or the 2F formulation (2% a.i.) at 0.25, 0.025 or 0.0025 mg/cm[2] a.i. for 1, 10 or 24 hours.  

Percent absorption of the 80WP formulation at 24 hours was 0.64, 1.02 and 1.83 for the respective high to low doses. After washing, 8.90, 9.53 and 7.35 percent of the dose remained in the washed skin.  Percent absorption of the 2F formulation at 24 hours was 0.44, 0.83 and 3.20 for the respective high to low doses.  After washing, 6.40, 8.85 and 10.64 percent of the dose remained in the washed skin.  Because of the combination effects of the low doses used and the low rates of absorption, the sample assay values tended to be scattered. The absorption patterns of the two formulations overlapped with no apparent differences. Because of the absorption pattern, the quantity remaining in the skin is not expected to add significantly to the total absorbed and should not be used for risk assessment.

This study is classified as Acceptable/guideline and satisfies the guideline requirement for a dermal absorption study in the rat (OPPTS §870.7600).

A.4.9	Immunotoxicity

	870.7800	Immunotoxicity

In an immunotoxicity study (MRID 48592601), Methoxyfenozide (98.0% a.i., Lot #6329B01) was administered to female Crl:CD(SD) rats (10/dose) in the diet targeted to deliver nominal doses of 0, 75, 300, or 1000 mg/kg bw/day (actual doses of 0, 76.9, 324, or 1076 mg/kg bw/day, respectively) for 28 days. On Day 25, animals in all groups were immunized with a suspension of sheep red blood cells (SRBC) by intravenous injection (2x10[8] SRBC/animal, 0.5 mL/animal dose volume). Animals in the positive control group received an intraperitoneal injection of cyclophosphamide at a dose of 20 mg/kg bw (1 mL/kg bw dose volume) on Days 24-28. All animals were evaluated for mortality, clinical signs, body weight changes, and gross pathology. The vehicle control and test substance treatment groups also were evaluated for food consumption and hematologic parameters. Immunotoxicity was assessed for all animals by an Enzyme-linked Immunosorbent Assay (ELISA). Spleen and thymus weights were measured at necropsy (Day 29) for all animals; liver weights were measured for the vehicle control and test substance treatment groups.

There were no test substance treatment-related effects on mortality, clinical signs, body weight changes, food consumption, or hematologic parameters. A statistically significant increase in relative but not absolute liver weight was found in the 300 and 1000 mg/kg bw/day groups; one animal in the 1000 mg/kg bw/day group also had a grossly observable enlarged liver. These increases in liver weights were treatment-related and are consistent with previously reported results.

The systemic toxicity LOAEL for Methoxyfenozide in female rats is 300 mg/kg bw/day (actual dose of 324 mg/kg bw/day), based on increased relative liver weight which was consistent with previously reported results. The NOAEL for systemic toxicity is 75 mg/kg bw/day (actual dose of 76.9 mg/kg bw/day).

For immunotoxicity, there were no test substance treatment-related effects on thymus and spleen weights or serum anti-SRBC IgM antibody levels as measured by an ELISA. A high inter-individual variability of anti-SRBC antibody level was noted in all the treatment groups as well as in the control group. Evaluation of individual animal data of this study did not show any trend or distribution that would demonstrate significant suppression of anti-SRBC antibody response. Animals in the positive control group showed marked decreases of anti-SRBC abtibody response. The positive control group confirmed the ability of the test system to detect immuno-suppressive effects and confirmed the validity of the study design. 

The Natural Killer (NK) cells activity was not evaluated in this study. The toxicology database for Methoxyfenozide does not reveal any evidence of treatment-related effects on the immune system. The only potential evidence of immunotoxicity in the submitted studies was anemia and other related blood effects observed in rats and dogs; however, additional parameters indicated these effects were compensatory response to the anemia, which was observed primarily after chronic dosing. The overall weight of evidence suggests that this chemical does not directly target the immune system. Under HED guidance, a NK cells activity assay is not required at this time.  

Under conditions of this study, the immunotoxicity NOAEL is 1000 mg/kg/day (actual dose of 1076 mg/kg/day); the LOAEL was not established. 

This immunotoxicity study is classified acceptable/guideline and satisfies the guideline requirement for an immunotoxicity study (OPPTS 870.7800) in rats. 


Appendix B.	Physical/Chemical Properties.

TABLE 2	 Physicochemical Properties of Methoxyfenozide.  
                                   Parameter
                                     Value
                                   Reference
Molecular Weight
368.47
D231303; H. Podall; 19 May 1997
Melting point/range (ºC)
206.1-208

pH
7.0

Density (g/cm[3])
0.740 +- 0.0081

Water solubility (mg/L at 20ºC)
3.3

Solvent solubility (g/L at 20ºC)
N-heptane	1.87
Xylene	3.38
1,2-dichloroethane	36.72
Methanol	192.92
2-Propanol	50.22

Vapor pressure (25ºC)
1.33 x 10[-5] Pa (1 x 10[-7] mm Hg)

Dissociation constant, pKa
None

Octanol/water partition coefficient (Log [KOW])
3.72 +- 0.04

UV/visible absorption (max)
ε 55313 at 203 nm
European Commission; SANCO/10384/202  -  rev. 4; 7 October 2004

Appendix C.  Review of Human Research

This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical.  These data, which include studies from the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1); the Agricultural Handler Exposure Task Force (AHETF) database; and the Outdoor Residential Exposure Task Force (ORETF) database; are subject to ethics review pursuant to 40 CFR 26, have received that review, and are compliant with applicable ethics requirements.  For certain studies that review may have included review by the Human Studies Review Board.  Descriptions of data sources as well as guidance on their use can be found at http://www.epa.gov/pesticides/science/handler-exposure-data.html and http://www.epa.gov/pesticides/science/post-app-exposure-data.html.
