

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

Date:	December 21, 2011

Subject:	Metaflumizone.  Revised Human-Health Risk Assessment Associated with a Section 3 Registration for a Fire Ant Bait for Application to Citrus, Tree Nuts, and Grape, and a new Section 3 Registration for a Fly Bait for Application around Industrial, Commercial, Agricultural and Recreational Facilities/Structures and Premises.  

PC Codes:  281250 (E Isomer); 281251 (Z isomer)
DP Barcode:  D393447
Decision No.:  384157
Registration No.:  7969-226
Petition No.:  7F7260
Regulatory Action:  Section 3
Risk Assessment Type:  single chemical aggregate
Case No.:  7446
TXR No.:  not available
CAS No.:  139968-49-3
MRID No:  none
40 CFR:  180.###

From:	Kelly M. Lowe, Environmental Scientist
	Tom Bloem, Chemist 
	Chester E. Rodriguez, Ph.D., Toxicologist
	Risk Assessment Branch 1 (RAB1)
	Health Effects Division (HED, 7509P)
	
Through:	Dana M. Vogel, Branch Chief
		George F. Kramer, Ph.D., Senior Chemist
		RAB1/HED (7509P)

To:	Kable Davis (RM 07)
	Registration Division (RD, 7505P)

Note:  This document supersedes D345134 (T. Bloem et al., 26-Jan-10).  An immunotoxicity study has been received and reviewed by the Agency and updates have been made to the Food Quality Protection Act (FQPA) Safety Factor (SF).  In addition, an assessment for a new Section 3 Registration for a fly bait product has been included in this document.

The HED of the Office of Pesticide Programs (OPP) is charged with estimating the risk to human health from exposure to pesticides.  The RD of OPP has requested that HED evaluate hazard and exposure data and conduct dietary, occupational, residential, and aggregate exposure assessments, as needed, to estimate the risk to human health that will result from all registered/ proposed metaflumizone uses.  The hazard characterization was provided by Chester Rodriguez (RAB1); the residue chemistry review and dietary exposure assessment were provided by Tom Bloem (RAB1); the occupational/residential exposure assessment and risk assessment was provided by Kelly Lowe (RAB1); and the drinking water assessment was provided by Mohammed Ruhman of the Environmental Fate and Effects Division (EFED).
                               Table of Contents
                                       
1.0 Executive Summary	3
2.0 Ingredient Profile	8
2.1 Summary of Registered/Proposed Uses	8
2.2 Structure and Nomenclature	10
3.0 Hazard Characterization/Assessment	10
3.1 Absorption, Distribution, Metabolism, Excretion (ADME)	11
3.2 Mammalian Toxicology	11
3.3 Toxicity Endpoint Selection	13
3.4 FQPA Safety Factor Considerations	17
3.4.1 Completeness of the Toxicology Database	17
3.4.2 Evidence of Neurotoxicity	17
3.4.3 Evidence of Sensitivity/Susceptibility in Developing Animals	17
3.4.4 Residual Uncertainty in the Exposure Database	18
4.0 Dietary Exposure/Risk Characterization	18
4.1 Metabolism (Crops, Livestock, and Rotational Crops) and Environmental Degradation	18
4.2 Analytical Methodology	19
4.3 Comparative Metabolic Profile	19
4.4 Drinking Water Residue Profile	20
4.5 Food Residue Profile	21
4.6 International Residue Limits and HED-Recommended Tolerances	22
4.7 Dietary Exposure and Risk	22
5.0 Residential Exposure/Risk Characterization	23
5.1 Residential Handler Exposure	23
5.2 Residential Post-application Exposure	24
5.3 Combined Residential Exposure	24
6.0 Aggregate Risk Assessments and Risk Characterization	25
6.1 Acute Aggregate Risk	26
6.2 Short-/Intermediate- Term Aggregate Risk	26
6.3 Chronic Aggregate Risk	27
6.4 Cancer Aggregate Risk	27
7.0 Cumulative Risk Characterization/Assessment	27
8.0 Occupational Exposure/Risk Characterization	27
8.1 Occupational Handler Exposure	27
8.2 Occupational Post-application Exposure	31
8.3 Restricted Entry Interval	31
9.0 Data Deficiencies	31
9.1 Toxicology	31
9.2 Residue Chemistry	31
9.3 Occupational and Residential Exposure	32
Appendix A.  Toxicity Profile Tables	33
Appendix B.  Chemical Names and Structures	38
1.0 Executive Summary

Metaflumizone (2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl)phenyl]ethylidene]-N-[4-(trifluoromethoxy)phenyl]hydrazinecarboxamide; E and Z isomers) is a semicarbazone insecticide that blocks the sodium channels of the nervous system in susceptible insects leading to inhibited feeding and paralysis (Lepidoptera and Coleoptera).  The E and Z isomers are typically present at an E:Z ratio of >9:1.  HED previously reviewed a petition concerning the application of metaflumizone as a pet care product and fire ant bait for use on lawns, landscapes, golf courses, and other non-cropland (D304496, R. Mitkus et al., 24-Jan-2006).   It should be noted that the pet use currently registered for metaflumizone is in the process of being cancelled; however, the use has been included in this risk assessment.  Existing stock of the registered product will continue to be sold, but registration will not be maintained beyond 2012.

BASF Corporation is currently proposing the application of Altrevin(TM) Fire Ant Bait Insecticide (EPA File Symbol No. 7969-###) to citrus fruits, grapes, and tree nuts and proposed the establishment of the following permanent tolerances for residues of metaflumizone (E and Z isomers):  Citrus Fruits, Group 10 - 0.01 ppm; Tree Nuts, Group 14 - 0.01 ppm; Grapes, table - 0.01 ppm; and Grapes, wine - 0.01 ppm.  In addition, BASF Corporation is also proposing the application of Metaflumizone Fly Bait (EPA Reg #7969-xxx) for control of the adult common housefly around industrial buildings, commercial facilities, and agricultural structures and premises.  It can also be used around recreational facilities and outdoor recreational areas.

A previous risk assessment (D345134, T. Bloem et.al, 26-Jan-10) assessed risks from the proposed new fire ant bait uses; however, the current risk assessment supersedes that document and reflects updates related to the FQPA SF and includes an assessment for the new Section 3 registration as a fly bait product.  

Hazard Characterization: Hematotoxicity (toxicity of the blood) was the primary toxic effect of concern following subchronic or chronic oral exposures to metaflumizone.  Splenic extramedullary hematopoiesis, increased hemosiderin, and anemia were the most common hematotoxic effects reported after repeated oral dosing with metaflumizone. Chronic oral (gavage) exposures to dogs resulted in slight decreases in mean corpuscular hemoglobin concentration and total hemoglobin, leading to increased plasma bilirubin, increased urinary urobilinogen, and increased hemosiderin in the liver.  In a chronic toxicity/carcinogenicity study in mice, anemia was observed in the form of increased hemosiderin in the spleen, increased mean absolute reticulocyte count, decreased mean corpuscular volume, and mean corpuscular hemoglobin. The postulated pesticidal mode of action of metaflumizone involves inhibition of sodium channels in target insect species; however, in mammals (rats), there were only clinical signs of neurotoxicity (i.e., piloerection and body temperature variations) with no neuropathology and in the presence of systemic toxicity (e.g., recumbency and poor general state) following acute or repeated exposures.  Similarly, several immune system organs seem to be affected following metaflumizone administration via the oral, dermal, and inhalation routes (e.g., the presence of macrophages in the thymus, lymphocyte necrosis in the mesenteric lymph nodes, and diffuse atrophy of the mandibular); however, there was no evidence of any functional deficits at the highest dose tested in a recently submitted and reviewed guideline immunotoxicity study.  Therefore, the clinical neurotoxicity signs and the effects on the immune system organs following metaflumizone administration are likely to be secondary to the hematotoxic effects.  Metaflumizone induced a malformation based on an absent subclavian artery at a relatively high dose in the developmental toxicity study in rabbits.  However, this was observed at the same dose as severe maternal toxicity, which included late-term abortions and other clinical signs of toxicity.  There was no evidence (quantitative or qualitative) of increased susceptibility following in utero exposures to rats or rabbit and following pre-and post natal exposures to rats. There was no evidence that metaflumizone is genotoxic and carcinogenicity studies with mice and rabbits were negative.

Dose-Response Assessment and FQPA SF Decision:  The points of departures (PoDs) and toxicological endpoints of concern are the same as those described in the risk assessment document dated January 26, 2010 (D345134).

The metaflumizone risk assessment team recommends that the FQPA SF be (a) reduced from 10x to 3x for all oral exposure scenarios, (b) retained at 10x for inhalation exposure scenarios, and (c) reduced from 10x to 1x for dermal exposure scenarios.  The reasons are as follows (for a more detailed discussion see Section 3.4): 
   1) Although metaflumizone shows evidence of potential immunotoxicity in the form of dose-related effects in the organs of the immune system across multiple studies with either the parent compound (composed of both E and Z isomers) or the Z-isomer of metaflumizone, evaluation of a recently submitted immunotoxicity study did not result in a point of departure lower than those from the last risk assessment and there were no immune system functional deficits (D345134, T. Bloem et al., 26-Jan-10).
   2) Reducing the FQPA SF at 3x for a database uncertainty for all oral exposure scenarios is adequate to protect against any toxicity that might occur at 2-fold lower doses in dietary exposures (absorption was noted to be 2-fold greater in dietary versus oral gavage studies).
   3) The FQPA SF of 10x is being retained for inhalation exposure scenarios for the use of a lowest-observed adverse-effect level (LOAEL) instead of a NOAEL.
   4) The FQPA SF for dermal exposure scenarios is being reduced from 10x to 1x since there is a route-specific study with a clear NOAEL and the concern for developmental toxicity is low.
   5) There are no residual concerns or uncertainties for pre- and/or postnatal toxicity.
   6) There is no clear evidence that metaflumizone directly targets the nervous system in mammals.
   7) The dietary analysis is conservative in that tolerance-level residues, 100% crop treated, and modeled drinking water estimates were assumed.  Therefore, HED concludes that while the submission of data/information by the petitioner addressing the residue chemistry deficiencies may conceivably result in adjustment of the maximum theoretical residue estimate, actual metaflumizone dietary exposure estimates will not be greater than those generated in the current risk assessment (i.e., incorporation of anticipated residues, percent crop treated estimates, and/or refined drinking water estimates will compensate for any increase in the maximum theoretical residue).
   8) The residential analysis is conservative in that health-protective assumptions were assumed along with the use of the Residential SOPs.  

HED notes that route-specific toxicity studies were selected for assessment of short-/intermediate-term dermal, inhalation, and oral exposures.  Short/intermediate-term dermal and inhalation exposures can be aggregated based on the effects on the immune system organs seen at the LOAEL in the selected studies.  Short/intermediate-term oral, dermal, and inhalation exposures can be aggregated based on the decreased body weight or decreased body-weight gain effects seen at the LOAEL in the selected oral and dermal studies and at doses above the LOAEL in the selected inhalation study.  

Dietary Exposure Assessment:  Acute and chronic metaflumizone dietary risk assessments were conducted using the Dietary Exposure Evaluation Model - Food Consumption Intake Database (DEEM-FCID, ver. 2.03) model.  DEEM-FCID(TM) (ver. 2.03) incorporates consumption data from the United States Department of Agriculture (USDA) Continuing Surveys of Food Intakes by Individuals (CSFII; 1994-1996 and 1998).  The acute and chronic dietary analyses assumed tolerance-level residues, 100% crop treated, and modeled drinking water estimates from the Pesticide Root Zone Model-Exposure Analysis Modeling System (PRZM-EXAMS).  The drinking water estimates were based on the application of metaflumizone as a fly bait on use sites such as recreational facilities and outdoor recreational areas including parks, picnic grounds, and camp grounds, which are represented by the turf modeling scenario [this scenario resulted in the highest estimated drinking water concentration (EDWC)].  DEEM(TM) (ver. 7.81) default processing factors were assumed for all commodities excluding grape raisin, grape juice, and citrus juice, which were reduced to 1 based on empirical data.  An acute dietary exposure estimate was generated for females 13-49 years old, but not for the remaining population subgroups since an endpoint attributed to a single dose was not identified for those populations.  The acute dietary exposure estimate for females 13-49 years old was <1% of the acute population-adjusted dose (aPAD) and, therefore, does not exceed HED's level of concern (LOC).  The chronic dietary exposure estimates were <1% of the cPAD and, therefore, do not exceed HED's LOC (children 1-2 years old were the most highly exposed population subgroup).  

Residential Risk:  Residential exposure is not anticipated from the proposed fire ant bait applications to citrus fruits, grapes and tree nuts; however, residential post-application exposure is anticipated from the proposed fly bait application scenarios.  The resulting dermal and incidental oral MOEs were greater than the LOCs of 100 and 300, respectively, and, therefore, were not of concern.  

There are already registered pet care and fire ant bait (for application to lawns, landscapes, golf courses, and other non-cropland) uses that may result in residential exposures.  As was noted above, the pet care product is in the process of being cancelled; however, the use has been included in this risk assessment.  The MOEs for the fire ant bait use (lawns, landscapes, golf courses, and other non-cropland) are >100 for dermal exposures, >300 for incidental oral exposures and >1000 for inhalation exposures and, therefore, do not exceed HED's LOCs.  The MOEs for the pet care product are >100 for dermal exposures and >300 for incidental oral exposures and, therefore, do not exceed HEDs LOC.  

Aggregate Risk:  In accordance with the FQPA, HED must consider and aggregate pesticide exposures and risks from dietary (food and water) and residential (dermal, inhalation, and incidental oral) sources.  When aggregating exposures and risks from these sources, HED considers the route and duration of exposure as well as the toxicological effects for each route.  Short-/intermediate-term dermal, oral, and inhalation exposures can be aggregated based on a common toxic effect (decreased body weight or decreased body-weight gain).  Based on this and the proposed/registered uses, aggregate acute, short-/intermediate-term, and chronic assessments were conducted.  An aggregate cancer risk assessment was not performed because metaflumizone is not considered to be a carcinogen.  

Acute/Chronic Aggregate Risk - Since there are no registered/proposed uses that result in acute or chronic residential exposure, the acute and chronic aggregate exposure assessment consists of exposure from food and water.  The acute (<1% aPAD) and chronic (1% cPAD) dietary exposure estimates do not exceed HED's LOC.  

Short-/Intermediate-Term Aggregate Risk  -  The short-term aggregate assessment combines food and drinking water exposure with the highest potential residential exposure.  The pet care products result in the highest potential residential exposure estimates, with the fly bait products resulting in the second highest.  Because the pet uses of metaflumizone are in the process of being cancelled, a short-term aggregate assessment was performed both for the pet care product and for the fly bait product.  Intermediate-term exposures are possible for the pet care product; however, since the points of departure for the short- and intermediate-term durations are the same for metaflumizone, the short-term aggregate assessment is protective of longer-term exposures for the pet care product.  For adults and the general U.S. population, the short- and intermediate-term aggregate assessment combines chronic dietary with residential post-application dermal exposure.  For young children, the short-and intermediate-term aggregate assessment combines chronic dietary exposure with incidental oral and dermal post-application exposures.  Since the LOC is different for dermal and oral exposures (100 and 300, respectively), the aggregate risk index (ARI) method was used to determine aggregate risk (ARIs > 1 are not a risk of concern).  The aggregate ARIs from food, water, and non-occupational exposures are >1 for both the fly bait and pet care uses for adults and children. Therefore, short-/intermediate-term aggregate risk estimates do not exceed HED's LOC.

Occupational Risk:  The occupational handler assessment for the proposed uses (fire ant bait on citrus fruit, grapes and tree nuts, and fly bait around industrial buildings, commercial facilities, agricultural structures and premises, recreational facilities and outdoor recreational areas) was completed assuming the maximum label application rates.  Broadcast applications were assumed to be made by tractor-drawn spreaders, belly grinders, and/or push-type spreaders.  Placing bait in bait stations was assumed to be done using a cup/spoon or by hand.  Based on the activity use pattern, the duration of exposure is expected to be short- and intermediate-term for occupational scenarios; long-term exposures (greater than 6 months) are not anticipated.  The same points of departure are used for short- and intermediate-term exposures; therefore, risks are the same for all durations of exposure.  The proposed labels require long-sleeved shirt and long pants and chemical-resistant gloves as dermal PPE for all applicators and other handlers.  

Occupational handler dermal and inhalation risk estimates were calculated.  The dermal and inhalation exposure risks for mixer/loaders, applicators, and mixer/loader/applicators are not of concern (i.e., MOEs >100 for dermal exposures and >1000 for inhalation exposures) at baseline and with the addition of gloves as recommended by the label.  Occupational dermal postapplication exposure was not assessed as it is not anticipated that workers will be exposed after application of the fly bait and/or the fire ant bait.  HED believes the presence of commercial workers in treated areas (e.g., industrial and commercial buildings) is minimal after application of the fly bait.  In the case of the fire ant bait, all applications are directed towards the soil surface and workers are not expected to frequent areas infested with active fire ants.    

Restricted Entry Interval (REI):  The proposed uses for the fly bait product are non-agricultural sites; therefore, a REI is not required.  For the fire ant bait product (citrus fruits, grapes and tree nuts), since a quantitative post-application dermal risk assessment has not been conducted, the default Worker Protection Standard (WPS) REI applies and is based on the acute toxicity category of the technical for dermal toxicity, skin irritation potential, and eye irritation potential.  Metaflumizone has low acute toxicity (Category IV) via the dermal route, and is neither a dermal irritant (Category IV), eye irritant (Category IV), nor a dermal sensitizer.  Therefore, the default REI of 12 hours would apply for metaflumizone.   

Environmental-Justice Considerations:  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.hss.energy.gov/nuclearsafety/env/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 USDA under CSFII and 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 toddlers, 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.

HED Recommendation:  Pending submission of a revised Section B, revised Section F, and analytical reference standards to the EPA National Pesticide Standards Repository; the toxicological, residue chemistry, and occupational/residential exposure databases support granting a conditional registration for the proposed metaflumizone uses.  In conjunction with this registration, the tolerances listed below should be established with the tolerance expression, commodity definitions, and numerical tolerances described as follows:  

Tolerances are established for residues of the insecticide metaflumizone, including its metabolites and degradates, in or on the commodities listed below.  Compliance with the tolerance levels specified below is to be determined by measuring only the sum of metaflumizone (E and Z isomers; 2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl) phenyl]ethylidene]-N-[4-(trifluoromethoxy)phenyl] hydrazinecarboxamide) and its metabolite 4-{2-oxo-2-[3-(trifluoromethyl) phenyl]ethyl}-benzonitrile, calculated as the stoichiometric equivalent of metaflumizone, in or on the following commodities:  Fruit, citrus, group 10 - 0.04 ppm; Nut, tree, group 14 - 0.04 ppm; Almond, hulls - 0.04 ppm; and Grape - 0.04 ppm.  

The conditional registration may be made unconditional pending resolution of the following issues: 

   * Cabbage metabolism study (46264326.der.wpd) - Information pertaining to sample extraction and analysis dates is required; if the interval from harvest to analysis is greater than the currently validated interval, then additional storage stability data will also be necessary. 
   * Cotton metabolism study (46264324.der.wpd) - Individual concentrations of the unknowns should be reported; if any unknown comprises >10% of the total radioactive residue (TRR), then further characterization/identification procedures may be required (based on these data additional residues may be included for risk assessment).  
   * Storage stability data - To support the subject field trial and processing studies, the following storage stability data are required which demonstrate the stability of metaflumizone (E and Z isomers) and M320I04:  grapes - 4.8 months; citrus fruit - 5.6 months; almond hulls - 6.5 months; and almond nutmeat - 5.8 months.  

2.0 Ingredient Profile

2.1 Summary of Registered/Proposed Uses

Registered:  HED previously reviewed a petition concerning the application of metaflumizone as a pet care product (maximum application rate of 0.002 lb ai/animal; 12 applications/year) and fire ant bait product for application to lawns, landscapes, golf courses, and other non-cropland (maximum application rate of 0.001 lb ai/acre; 4 applications/year; homeowner application permitted) (D304496, R. Mitkus et al., 24-Jan-2006).  It should be noted that the pet use currently registered for metaflumizone is in the process of being cancelled; however, the use has been included in this risk assessment.  Existing stock of the registered product will continue to be sold, but registration will not be maintained beyond 2012.

Proposed:  The petitioner is proposing application of Altrevin(TM) Fire Ant Bait Insecticide (EPA Reg. No. 7969-###; granular (G); 0.063% active ingredient) to citrus fruits, grapes, and tree nuts (see Table 2.1.1).  The label also includes directions for use in orchards and nurseries containing field- or container-grown nonbearing stone and pome fruit trees (application within a year of harvest is prohibited).  The proposed label includes a 12-hour REI.  On page 3 of the label, HED requests that the petitioner list the crops for each crop group as defined in 40 CFR 180.41 and eliminate the "including but not limited to" phrase.  A revised Section B is requested.  

In addition, the Registrant is proposing the use of metaflumizone as a granular fly bait for control of the adult common housefly around industrial buildings, commercial facilities, and agricultural structures and premises.  It can also be used around recreational facilities and outdoor recreational areas.  The end-use product is Metaflumizone Fly Bait (EPA Reg #7969-xxx; granular (G)), containing 0.063% active ingredient.  The bait can be broadcast over large areas as a scatter bait or placed in bait stations/trays.  The maximum application rate proposed for broadcast applications (scatter bait) is 0.014 lb ai/A, and for bait stations/trays is 2 oz bait/station hung or placed at a density of 8-10 stations/2000 square feet.  

Table 2.1.1:  Summary of Proposed Directions for Metaflumizone.
                    Application Timing; Type; and Equipment
                                   Product; 
                                  Formulation
                                [EPA Reg. No.]
                               Application Rate
                           Max. No. App. per Season
                            Max. Seasonal App. Rate
                                      PHI
                                    (days)
                        Use Directions and Limitations
Citrus trees (citrus and Fortunella spp.):  including but not limited to orange (sweet, sour), lemon, lime, grapefruit, citrus hybrids (chironja, tangelo, tangor), kumquat, Mandarin (tangerine), pummelo, and Satsuma mandarin
Nut trees:  including, but not limited to almond, beech nut, Brazil nut, butternut, cashew, chestnut, chinquapin, filbert, hickory nut, macadamia nut, pecan, and walnut
Grape vineyards; and orchards and nurseries containing field- or container-grown nonbearing stone and pome fruit trees
Postemergence;
Broadcast; Ground
Altrevin(TM) Fire Ant Bait Insecticide; 0.063% G
[7969-###]
0.0006-0.001 lb ai/acre
4
0.004 lb ai/acre
5[1]
Broadcast applications are to be made in areas having a mound density of at least 1 mound per 2,000 square feet.  Otherwise, individual mound spot treatments are to be made (see below).  A minimum retreatment interval (RTI) of 4 weeks is proposed.
Postemergence;
Spot; Ground
Altrevin(TM) Fire Ant Bait Insecticide; 0.063% G
[7969-###]
0.00004-0.00008
lb ai/mound; 
not to exceed 0.001 lb ai/acre
not indicated
0.004 lb ai/acre
5[1]
Spot applications are to be made in areas having a mound density of less than 1 mound per 2,000 square feet.  Otherwise, broadcast applications are to be made (see above).  A minimum RTI of 4 weeks is proposed.
Around industrial buildings, commercial facilities, agricultural structures and premises, recreational facilities and outdoor recreational areas.
Postemergence; Broadcast; Ground[2]
Metaflumizone Fly Bait; 
0.063% G
[7969-###]
0.014 lb ai/acre

not indicated
not indicated
NA
Do not apply in side homes.  Apply in locations where children and pets cannot access or come into contact with bait granules.

Do not apply in are where livestock can ingest or contact bait.

Do not use (except for bait station use) in edible product areas where food is commercially prepared or process or in serving areas when food exposed.

Do not place bait in piles or in wet/moist areas.

Do not pile or heap bait in station or tray.

Reapply as bait is consumed to maintain control.
Postemergence; Spot; Ground[3]
Metaflumizone Fly Bait; 
0.063% G
[7969-###]
0.000079 lb ai/station and 8-10 stations/2000 ft[2]




1. Application to non-bearing pome and stone fruit trees is permitted up to 1-year before first harvest.
2.  Locations include:  (1) Outside of food and beverage plants, meat and poultry processing plants, food handling establishments, restaurants, cafes, fast-food establishments, supermarkets, farm markets, bakeries, commissaries, warehouses, and the refuse dumpsters associated with these establishments.  (2) Outside of livestock handling and feeding facilities including broiler  and layer houses, swine production facilities, livestock barns, horse stables, milking parlors, dairy barns, feed lots, feed storage buildings, feed silos, and other animal handling and feeding facilities. (3) Indoors in livestock handling and feeding facilities.  Only in areas where livestock cannot come in contact with or ingest bait granules; such as walkways or manure pits in caged layer houses, dairy barns, and swine facilities.  (4) Outdoors around recreational facilities and outdoor recreational areas including parks, picnic grounds, campgrounds, and outdoor latrines.
3. Locations include:  (1) In and around food and beverage processing plants, meat and poultry processing plants, food handling establishments, restaurants, cafes, fast-food establishments, supermarkets, farm markets, bakeries, commissaries and warehouses.  (2) In and around livestock handling and feeding facilities including broiler and layer houses, swine production facilities, livestock barns, horse stables, milking parlors, dairy barns, feed lots, feed storage buildings, feed silos and other animal handling and feeding facilities.  

2.2 Structure and Nomenclature

The chemical structure and nomenclature of metaflumizone and the physicochemical properties of the technical grade of metaflumizone are presented in Tables 2.2.1 and 2.2.2, respectively.

Table 2.2.1:  Metaflumizone Nomenclature.
Chemical structure
                                       
Common name
Metaflumizone
Company experimental name
BAS 320 I
IUPAC name
(EZ)-2'-[2-(4-cyanophenyl)-1-(α,α,α-trifluoro-m-tolyl)ethylidene]-4-(trifluoromethoxy)carbanilohydrazide
CAS name
2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl)phenyl]ethylidene]-N-[4-(trifluoromethoxy)phenyl]hydrazinecarboxamide
CAS registry number
139968-49-3
End-use product (EP)
Altrevin Fire Ant Bait Insecticide (0.063% G formulation; EPA Reg. No. 7969-###)

Table 2.2.2:  Physicochemical Properties of Metaflumizone.
Melting point
Two melting points observed at approximately 127 ºC and 186 ºC.
MRID 46264204
pH
6.48 at 25 ºC (1% aqueous suspension)
MRID 46264524
Density (20 ºC)
1.461 g/cm[3]
MRID 46264204
Water solubility (20 ºC)
D.I. water	1.79 μg/L
pH 5	1.35 μg/L
pH 7	1.81 μg/L
pH 9	1.73 μg/L
MRID 46264208
Solvent solubility (20 ºC)
Acetone	142.7 mg/L
Acetonitrile	60.3 mg/L
DCM	92.7 mg/L
EtOAc	159.7 mg/L
Heptane	0.0084 mg/L
Methanol	13.95 mg/L
Toluene	3.96 mg/L
MRID 46264212
Vapor pressure
1.24 x 10[-8] Pa at 20 ºC
MRID 46264206
Dissociation constant, pKa
None in pH range 2-12
MRID 46264217
Octanol/water partition coefficient, Log(KOW)
Log POW = 5.1 (Z isomer)
Log POW = 4.4 (E isomer)
MRID 46264213
UV/visible absorption spectrum
Molar absorptivity:  3.81x10[4] L/Mcm at 234 nm; 1.93x10[4] L/Mcm at 280 nm. 
MRID 46264207

3.0 Hazard Characterization/Assessment

The hazard characterization and toxicity profile tables (Appendix A) for metaflumizone have been updated since the last risk assessment (D345134, T. Bloem, 26-Jan-10) in order to include an immunotoxicity study recently submitted and reviewed by the Agency.  This document includes information related to that study and updates to the FQPA SF. Oral gavage and dietary exposures to metaflumizone are addressed when appropriate since an absorption study (MRID# 47249001) demonstrated an approximately 2-fold greater absorption from dietary exposures as compared to oral gavage dosing. Because of this difference in absorption, toxicity via dietary exposure has the potential to occur at doses 2-fold lower than those currently identified using gavage dosing (for more details, see D345134, T. Bloem, 26-Jan-10).

3.1 Absorption, Distribution, Metabolism, Excretion (ADME)

Gavage Route:  Metaflumizone was poorly absorbed from the gastrointestinal (GI) tract of rats following oral dosing via gavage at 30 and 1000 mg/kg with an apparent inverse dose-absorption relationship (up to 7% was absorbed following a 30 mg/kg dose; up to 2% after a 1000 mg/kg dose).  Following a single dose (30 mg/kg/day) of radioactive metaflumizone by gavage, residues (up to 0.6% of the dose) were detected in the liver only.  After two weeks of repeated daily dosing at 30 mg/kg/day, the tissue distribution of metaflumizone was increased, with up to 1% of the administered dose measured in the liver, kidney, muscle, fat, and plasma.  Average concentrations in fat did not decrease by 168 hrs following the last dose in a repeated dosing paradigm, a finding that is consistent with the lipophilic nature of metaflumizone (log KOW = 5.1).  These observations, as well as the relatively long elimination half-life of metaflumizone (up to 17 days, depending on which ring is labeled) and the very large volume of distribution of metaflumizone in rats (up to 156 L) indicate that the small fraction of metaflumizone absorbed from the GI tract following gavage dosing is slowly eliminated from the body.  There were no major sex-related differences in excretion.  Approximately 90% of the administered dose was excreted in the feces as untransformed metaflumizone seven days following a single dose, with 1-2% excreted in urine.  The absorbed fraction of metaflumizone was extensively biotransformed, primarily by hydroxylation of the aniline or benzonitrile ring or hydrolysis of the central hydrazine carboxamide group, and all metabolites were excreted in either the urine or bile. 

3.2 Mammalian Toxicology

A summary of the subchronic and chronic toxicity and genotoxicity databases for metaflumizone, its Z-isomer, and the goat/plant/soil metabolite M320I23 is found in Table A.2.  

Gavage Dosing with Metaflumizone

Metaflumizone technical (96% metaflumizone; mixture of ~90% E-isomer:10% Z-isomer) demonstrated low acute toxicity via the oral, dermal, and inhalation routes of exposure (Category IV).  It is neither a dermal irritant (Category IV), an eye irritant (Category IV), nor a dermal sensitizer.  Acute toxicity testing of the Z-isomer and the goat/plant/soil metabolite M320I23 yielded results similar to those for the technical product (Table A.1).

Metaflumizone caused both hematotoxicity (toxicity of the blood) and immunotoxicity as primary toxic effects following subchronic or chronic oral exposure.  Metaflumizone induced slight anemia and/or a compensatory extramedullary hematopoiesis in the spleen in the 90-day oral toxicity study in rats.  Similar hematological effects were not observed at the doses tested in the chronic toxicity/carcinogenicity study in rats, however, a negative finding may have been due to an adaptive response to the anemia following long-term exposure in this species.  In the chronic toxicity study in dog, anemia was observed in the form of slight decreases in mean corpuscular hemoglobin concentration and total hemoglobin leading to increased plasma bilirubin, increased urinary urobilinogen, and increased hemosiderin in the liver.  In the chronic/carcinogenicity study in mice, anemia in the form of increased hemosiderin in the spleen, increased mean absolute reticulocyte count, and decreased mean corpuscular volume and mean corpuscular hemoglobin were observed in both males and females. 

Hematotoxicity and/or immunotoxicity were also observed following dermal exposure to metaflumizone.  In a rat 90-day dermal toxicity study, increased hemosiderin was observed in the livers of females, along with increased macrophages in the thymus, lymphocyte necrosis in the mesenteric lymph nodes, and diffuse atrophy of the mandibular lymph node.  Lymphocyte necrosis in the mesenteric lymph node was also the critical effect (i.e., observed at the lowest dose) reported in a rat 28-day inhalation toxicity study, thereby supporting the conclusion that metaflumizone is immunotoxic across all routes of exposure tested.

The potential neurotoxicity of metaflumizone was assessed in both acute and subchronic neurotoxicity studies.  There was no evidence of neurotoxicity in the acute neurotoxicity study in rats up to the highest dose tested (the limit dose).  Piloerection and body temperature variations were noted in the subchronic neurotoxicity study in rats, and salivation and ataxia were observed at the high dose in a chronic study with dogs.  However, reduced general condition and/or recumbency, indicators of general systemic toxicity, were also observed in both sexes in both studies.  Thus, although metaflumizone is postulated to operate by way of a neurotoxic mechanism of action (sodium channel inhibition) in insect species, it is difficult to separate the clinical signs of neurotoxicity from a general systemic toxic effect in mammals.

In the developmental toxicity study in rat, toxicity to the offspring was not observed at any dose, whereas mild maternal toxicity (decreased body-weight gain) was observed at the highest dose tested.  In the developmental toxicity study in rabbits, the malformation absent subclavian artery was observed at the same dose as severe maternal toxicity, which included late-term abortions and clinical signs of toxicity.  In the 2-generation reproductive toxicity study in rats, perinatal mortality was observed in offspring.  However, the mortality was most likely the result of the improper nursing behavior, as well as the decreased body weight and clinical signs of toxicity, exhibited by the parents at the same dose.  Similar findings were observed in the range-finding developmental neurotoxicity study in rats, in which pup mortality was observed at the same dose as clinical signs of toxicity and total litter loss in maternal animals.

There was no evidence indicating that metaflumizone is genotoxic and carcinogenicity studies with mice and rats were negative.    

Oral Gavage Dosing with the Z-isomer of Metaflumizone:  
In a 3-month oral study with the Z-isomer alone (99.7%), groups of 10 Sprague-Dawley rats/sex were gavaged daily at doses of 0, 100, 300, or 1000 mg/kg/day for 90 days.  Mortality, reduced general condition, piloerection, and decreased overall motor activity were observed in females at the LOAEL of 300 mg/kg/day (NOAEL = 100 mg/kg/day).  In males, decreased overall motor activity was observed at the highest dose tested only (LOAEL = 1000 mg/kg/day; NOAEL = 300 mg/kg/day).  A comparison with the subchronic (90-day) neurotoxicity study in rats using metaflumizone technical (LOAEL = 150 mg/kg/day; NOAEL = 36 mg/kg/day), indicates that the Z-isomer is most likely less potent than metaflumizone technical (predominantly E-isomer), because it caused toxicity at doses that were 2-fold and 7-fold higher than the technical active in females and males, respectively.  In addition, like metaflumizone technical, the Z-isomer of metaflumizone was negative for mutagenicity with and without metabolic activation in an in vitro bacterial reverse mutation (Ames) assay.

Oral Gavage Dosing with Metabolite M320I23:  
M320I23 is a metabolite of metaflumizone that is generated in soil, plants (cotton, tomato, white cabbage), and goats, but not in rats.  No adverse effects were observed in a 3-month oral (gavage) study of M320I23 in rats.  M320I23 was negative for mutagenicity in an in vitro bacterial reverse mutation (Ames) test with and without metabolic activation and an in vitro mammalian gene mutation study at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus in Chinese hamster ovary (CHO) cells without metabolic activation (inconclusive results were obtained in the presence of metabolic activation due to compound precipitation).  M320I23 was also negative in an in vitro mammalian chromosomal aberration study with V79 cells without metabolic activation.  Although the metabolite was positive in this in vitro study with metabolic activation, it was negative in an in vivo mammalian cytogenetics assay (mouse micronucleus test), which would be considered a more relevant test system for clastogenicity since it was tested in a whole animal.  The overall weight of the evidence for this metabolite, therefore, indicates that M320I23 is less toxic than metaflumizone technical and non-mutagenic like the parent compound.

Dietary Dosing with Metaflumizone

Five short-term toxicity studies, in which rats or mice were exposed to metaflumizone in the diet, were submitted to the Agency after the original data package submission.  These studies were conducted early in the development of metaflumizone as an insecticide, and the results of these studies led to the (appropriate) decision by the registrant to conduct all of its guideline studies using gavage dosing.  In every study, decreased body weight and body-weight gains were observed in the presence of decreased food consumption.  Because the decreases in body weight were observed only in the presence of decreased food consumption at the doses tested in these studies (>=3.8 mg/kg bw/day), the effect on body weight could not be attributed to a direct effect of treatment, but rather was due to the decreased food consumption, which was most likely caused by a lack of palatability of the test substance when administered in the diet.  The results from these five studies were supported by two additional studies, also later submitted to the Agency, which demonstrated that when given a preference in a free-choice feeding regimen, rats strongly preferred untreated control feed and avoided diet that was treated with metaflumizone; and when given no preference in an alternate-day feeding regimen, rats ate less and lost weight on those days in which they were forced to eat diet treated with metaflumizone.  The results of these seven studies were supported by an eighth study in which no effect on body weight or food consumption was observed when rats were administered metaflumizone by gavage at doses that were similar to the dietary studies.  Because the lower body weight observed in the dietary studies was caused by the animals eating less due to the unpalatability of metaflumizone, and not to direct toxicity of the test compound (for example, on intermediary metabolism), they are not relevant for endpoint selection for risk assessment.  However, it would be anticipated that humans, like rodents, might also smell and not eat food that contained residues of metaflumizone at the levels tested in these additional animal toxicity studies, thereby limiting ingestion of the compound.

3.3 Toxicity Endpoint Selection

A summary of the toxicological endpoints and doses chosen for the exposure scenarios relevant for the current human-health risk assessment are summarized below and in Tables 3.3.1 (for dietary and residential exposure) and 3.3.2 (for occupational exposure).  Since the last risk assessment (D345134, T. Bloem, 26-Jan-10), an immunotoxicity study was submitted and reviewed by the Agency.  The results of the study did not impact the toxicity endpoint selection from the last risk assessment; except for the FQPA factor, which was previously retained at 10x due to the absence of an immunotoxicity study (see FQPA considerations below; Section 3.4). Since long-term dermal and inhalation exposures are not expected with the current use pattern, endpoints for these exposure scenarios are not presented.  

Dietary and Residential Exposure

Acute Dietary Endpoint (General population including infants and children):  An acute dietary endpoint was not established for this population group since an endpoint of concern (effect) attributable to a single dose was not identified in the database.  Studies considered for this endpoint included the acute neurotoxicity study for which a LOAEL was not observed.  

Acute Dietary Endpoint (Females 13-49 years old): This endpoint was established based on a developmental effect observed in the rabbit developmental toxicity study that can be potentially due to a single dose of metaflumizone.  The effects consisted of an absent subclavian artery in the offspring at the LOAEL of 300 mg/kg bw/day metaflumizone (NOAEL = 100 mg/kg bw/day).  The rat developmental toxicity study was also considered for this endpoint; however, no developmental effects were observed in this study at the highest dose tested of 120 mg/kg bw/day metaflumizone.  A combined uncertainty factor (UF) of 300 was applied to account for interspecies (10x) and intraspecies (10x) extrapolation and a FQPA SF of 3x was retained because the rabbit developmental toxicity study was performed via oral gavage dosing.  Dietary exposures (which are more relevant for human exposures) exhibited an approximately 2-fold greater absorption into the systemic circulation and, thus, can potentially lead to toxicity at 2-fold lower levels of exposure.  Thus, the aPAD for females 13-49 years old is estimated to be 0.33 mg/kg bw/day.

Chronic Dietary Endpoint: This endpoint was based on results of a chronic toxicity study in dogs via capsule administration.  The effects at the LOAEL of 30 mg/kg bw/day (NOAEL = 12 mg/kg bw/day) consisted of reduced general health condition, slight to severe ataxia, recumbency, and severe salivation, decreases in MCHC and total Hb and increased bilirubin, increased urobilinogen, and increased hemosiderin in the liver.  A combined UF of 300 was applied to account for interspecies (10x) and intraspecies (10x) extrapolation and an FQPA factor of 3x being retained for the higher absorption observed with dietary exposures to metaflumizone (see above).  Thus, the cPAD is estimated to be 0.040 mg/kg bw/day.

Incidental Oral (Short- and Intermediate-Term): This endpoint was selected on the basis of the maternal effects observed in the rat 2-generation reproductive toxicity study at the LOAEL of 50 mg/kg bw/day metaflumizone (NOAEL = 20 mg/kg bw/day).  Maternal toxicity consisted of poor general health and body weight deficits that were also associated with improper nursing behavior.  Similar effects were also noted in a developmental neurotoxicity study (gavage, range finding) also considered for this endpoint. In this study, poor maternal health was also observed at the LOAEL of 120 mg/kg bw/day metaflumizone (NOAEL = 80 mg/kg bw/day).  Both studies considered for this endpoint achieved a clear NOAEL for the offspring effects, but the NOAEL of 20 mg/kg bw/day for the 2-generation reproductive toxicity study is considered more protective.  A combined UF of 300 was applied to account for interspecies (10x) and intraspecies (10x) extrapolation and an FQPA SF of 3x to account for the 2-fold greater absorption observed in dietary versus oral gavage exposures (see above).  The LOC is 300.

Dermal (Short- and Intermediate-Term):  This endpoint was based on a rat 90-day dermal toxicity study in which deficits in body weight, body-weight gain and food consumption (in males and females); anogenital smearing;  increased macrophages in the thymus; lymphocyte necrosis in the mesenteric lymph nodes; diffuse atrophy of the mandibular lymph node; and increased hemosiderin in the liver (females only) were observed at the LOAEL of 300 mg/kg bw/day (NOAEL = 100 mg/kg bw/day).  The LOC is 100 based on a combined UF of 100 for interspecies (10x) and intraspecies (10x) extrapolation.

Inhalation (Short- and Intermediate-Term):  There is a 28-day inhalation study that is adequate for both exposure durations.  There was no NOAEL identified for female rats.  At the LOAEL of 0.10 mg/L metaflumizone (NOAEL = 0.03 mg/L), histopathology of the nasal tissues, lungs, thymus, prostate, and adrenal cortex was observed in males.  The LOAEL identified in females resulted in lymphocyte necrosis in the mesenteric lymph node.  The FQPA of 10x is being retained for lack of a NOAEL for females, in addition to the combined UF of 100 for interspecies (10x) and intraspecies (10x) extrapolation.  

HED notes that route-specific toxicity studies were selected for assessment of short-/intermediate-term dermal, inhalation, and oral exposures.  Short/intermediate-term dermal and inhalation exposures can be aggregated based on the immunotoxic effects seen at the LOAEL in the selected studies.  Short/intermediate-term oral, dermal, and inhalation exposures can be aggregated based on the decreased body weight or decreased body-weight gain effects seen at the LOAEL in the selected oral and dermal studies and at doses above the LOAEL in the selected inhalation study.  

Table 3.3.1:  Summary of Toxicological Doses and Endpoints for Metaflumizone Used in Residential Human-Health Risk Assessments.[1]
                               Exposure Scenario
                       Dose Used in Risk Assessment, UF
                      FQPA SF or LOC for Risk Assessment
                        Study and Toxicological Effects
Acute Dietary-general population, including infants and children
                                      N/A
                                      N/A
An endpoint of concern (effect) attributable to a single dose was not identified in the database.  Quantification of acute risk to general population including infants and children is not required.
Acute Dietary-females 13-49 years old
NOAEL = 100 mg/kg/day
UF = 100
FQPA SF = 3x 

aPAD =aRfD = 0.33 mg/kg/day
Developmental toxicity (rabbit; gavage dosing); Offspring LOAEL = 300 mg/kg/day based on absent subclavian artery.
Chronic Dietary-general population, including infants and children
NOAEL = 12 mg/kg/day
UF = 100
FQPA SF = 3x 

cPAD =cRfD = 0.04 mg/kg/day
Chronic toxicity (dog; capsule dosing); LOAEL = 30 mg/kg/day based on reduced general health condition, slight to severe ataxia, recumbency, and severe salivation, decreases in MCHC and total Hb and increased bilirubin, increased urobilinogen, and increased hemosiderin in the liver.
Short- (1-30 days) and Intermediate- (1-6 months) Term Incidental Oral 
NOAEL = 20 mg/kg/day
LOC (residential) = MOE < 300
2-generation reproduction (rat); Maternal LOAEL = 50 mg/kg/day based on poor general health and decreased body weight.
Short- (1-30 days) and Intermediate-(1-6 months) Term Dermal
NOAEL = 100 mg/kg/day
LOC (residential) = MOE < 100

LOC (occupational) = MOE < 100 
90-day dermal (rat); LOAEL = 300 mg/kg/day based on decreased BW gain and food consumption (M&F); anogenital smearing, decreased BW, increased macrophages in the thymus, lymphocyte necrosis in the mesenteric lymph nodes, diffuse atrophy of the mandibular lymph node, and increased hemosiderin in the liver (F).
Short- (1-30 days) and Intermediate- 
(1-6 months) Term Inhalation
LOAEL = 0.03 mg/L[*]
NOAEL not observed
LOC (residential) = MOE < 1000 
(includes 10x FQPA SF in form of UFL)

LOC (occupational) = MOE < 1000
(includes 10x UFL)
28-day inhalation (rat); LOAEL = 0.03 mg/L[*] based lymphocyte necrosis in the mesenteric lymph node (F).
Cancer (oral, dermal, inhalation)
Classification:  Not likely to be carcinogenic to humans.
[1]  UF = uncertainty factor, FQPA SF = FQPA Safety Factor, NOAEL = no-observed adverse-effect level, LOAEL = lowest-observed adverse-effect level, RfD = reference dose (a = acute, c = chronic), PAD = population-adjusted dose, MOE = margin of exposure, LOC = level of concern, N/A = Not Applicable, UFL = uncertainty factor for lack of a NOAEL and extrapolation of a 28-day study for longer durations.
[*]  0.03 mg/L x 100% absorption x 45.2 L/hr/kg (conversion factor) x 6 hrs/day (exposure duration) x 1 (activity factor) = 8 mg/kg bw/day

Occupational Exposure

Dermal (Short- and Intermediate-Term):  This endpoint was based on a rat 90-day dermal toxicity study in which deficits in body weight, body-weight gain and food consumption (in males and females); anogenital smearing;  increased macrophages in the thymus; lymphocyte necrosis in the mesenteric lymph nodes; diffuse atrophy of the mandibular lymph node; and increased hemosiderin in the liver (females only) were observed at the LOAEL of 300 mg/kg bw/day (NOAEL = 100 mg/kg bw/day).  The LOC is 100 based on a combined UF of 100 for interspecies (10x) and intraspecies (10x) extrapolation.

Inhalation (Short- and Intermediate-Term): There is a 28-day inhalation study that is adequate for both exposure durations.  There was no NOAEL identified for female rats.  At the LOAEL of 0.10 mg/L metaflumizone (NOAEL = 0.03 mg/L), histopathology of the nasal tissues, lungs, thymus, prostate, and adrenal cortex was observed in males.  The LOAEL identified in females resulted in lymphocyte necrosis in the mesenteric lymph node.  The FQPA of 10x is being retained for lack of a NOAEL for females, in addition to the combined UF of 100 for interspecies (10x) and intraspecies (10x) extrapolation.  

Table 3.3.2:  Summary of Toxicological Doses and Endpoints for Metaflumizone Used in Occupational Human-Health Risk Assessments.[1]
                               Exposure Scenario
                       Dose Used in Risk Assessment, UF
                      FQPA SF or LOC for Risk Assessment
                        Study and Toxicological Effects
Short- (1-30 days) and Intermediate-(1-6 months) Term Dermal
NOAEL = 100 mg/kg/day
LOC (residential) = MOE <100

LOC (occupational) = MOE <100 
90-day dermal (rat); LOAEL = 300 mg/kg/day based on decreased BW gain and food consumption (M&F); anogenital smearing, decreased BW, increased macrophages in the thymus, lymphocyte necrosis in the mesenteric lymph nodes, diffuse atrophy of the mandibular lymph node, and increased hemosiderin in the liver (F).
Short- (1-30 days) and Intermediate- 
(1-6 months) Term Inhalation
LOAEL = 0.03 mg/L[*]
NOAEL not observed
LOC (residential) = MOE <1000 
(includes 10x FQPA SF in form of UFL)

LOC (occupational) = MOE <1000
(includes 10x UFL)
28-day inhalation (rat); LOAEL = 0.03 mg/L[*] based on lymphocyte necrosis in the mesenteric lymph node (F).
[1]  UF = uncertainty factor, FQPA SF = FQPA Safety Factor, NOAEL = no-observed adverse-effect level, LOAEL = lowest-observed adverse-effect level, RfD = reference dose (a = acute, c = chronic), PAD = population-adjusted dose, MOE = margin of exposure, LOC = level of concern, N/A = Not Applicable, UFL = uncertainty factor for lack of a NOAEL and extrapolation of a 28-day study for longer durations.
[*]  0.03 mg/L x 100% absorption x 45.2 L/hr/kg (conversion factor) x 6 hrs/day (exposure duration) x 1 (activity factor) = 8 mg/kg bw/day

3.4 FQPA Safety Factor Considerations

The metaflumizone risk assessment team recommends that the FQPA SF be reduced from 10x to 3x  for all oral exposure scenarios, be retained at 10x for inhalation exposure scenarios, and be reduced to 1x for dermal exposures. 

3.4.1 Completeness of the Toxicology Database

The toxicology database for metaflumizone is adequate for registration. In the last risk assessment (D345134, T. Bloem, 26-Jan-10) the only database deficiency noted was an immunotoxicity study.  Since then, an immunotoxicity study has been received and evaluated by the Agency.  The results of the study did not result in a point of departure lower than those from the last risk assessment.  

A difference in absorption was noted between oral gavage and dietary dosing. Absorption via the diet, a more relevant route of exposure for oral human risk assessments, was noted to be greater than via gavage by a factor of 2.  Therefore, toxicity via the diet can be expected at doses that are approximately 2-fold lower than those currently selected for dietary and incidental oral risk assessments, which are based on gavage dosing.  Thus, an FQPA SF of 3x is being retained in the form of a database uncertainty factor for all oral exposure scenarios to protect against any toxicity that might result via the dietary (oral) route.

In the case of inhalation exposure scenarios, the FQPA SF of 10x is being retained as an uncertainty factor for the use of a lowest-observed-adverse-effect level (LOAEL) in the absence of a NOAEL from a 28-day inhalation study. 

The reduction of the FQPA SF from 10x to 1x for dermal exposure scenarios is justified since there is a route-specific study with a clear NOAEL. 

3.4.2 Evidence of Neurotoxicity

Clinical signs indicative of neurotoxicity were observed in several studies; however, these signs were generally observed in the presence of poor animal health (e.g., reduced general health condition, loss of body weight, death).  In addition, no neuropathology was observed in any study with metaflumizone.  No signs of abnormal offspring behavior, central nervous system (CNS) malformations, effects on offspring brain weights, or effects on offspring sexual maturation were observed in the developmental or 2-generation reproduction studies.  No adverse effects were reported on motor activity or in the functional observational battery in the chronic/carcinogenicity study in rats.  There was no evidence of neurotoxicity in the acute neurotoxicity test in rat up to the limit dose.  

3.4.3 Evidence of Sensitivity/Susceptibility in Developing Animals

There are no residual concerns or uncertainties for increased sensitivity/susceptibility in developing animals resulting from pre- and/or postnatal exposure.  

3.4.4 Residual Uncertainty in the Exposure Database

The dietary analysis is conservative in that tolerance-level residues, 100% crop treated, and modeled drinking water estimates were assumed.  Therefore, HED concludes that while the submission of data/information by the petitioner addressing the residue chemistry deficiencies may conceivably result in adjustment of the maximum theoretical residue estimate, actual metaflumizone dietary exposure estimates will not be greater than those generated in the current risk assessment (i.e., incorporation of anticipated residues, percent crop treated estimates, and/or refined drinking water estimates will compensate for any increase in the maximum theoretical residue).  The residential analysis is conservative in that health-protective assumptions were assumed along with the use of the Residential SOPs.  

4.0 Dietary Exposure/Risk Characterization
residue chemistry summary - D345540, T. Bloem, 26-Jan-10
dietary exposure - D393549, T. Bloem, 20-Sep-11
drinking water - D367556, J. Melendez, 3-Aug-2011

4.1 Metabolism (Crops, Livestock, and Rotational Crops) and Environmental Degradation

The petitioner previously submitted cotton, cabbage, tomato, goat, and hen metabolism studies and confined rotational crop studies conducted with metaflumizone uniformly ring-labeled in the [benzonitrile-[14]C] metaflumizone (B-label) and [trifluoromethoxyphenyl-[14]C] metaflumizone (T-label) rings.  Based on these data and information concerning environmental degradation of metaflumizone, HED concluded that the residue of concern in plants, livestock, rotational crops, and drinking water are as defined in Table 4.1.1.  For further information concerning these conclusions, see the HED risk assessment document D304496 (R. Mitkus et al., 24-Jan-06).  

HED notes that the residue of concern in ruminants is to be reevaluated if the ruminant dietary burden increased significantly.  Almond hulls (90% dry matter; dairy only) and dried citrus pulp (91% dry matter; beef and dairy) are the only feed commodities associated with the current petition (maximum of 10% of the diet).  HED previously estimated beef and dairy cattle dietary burdens at 2.53 ppm and 0.36 ppm, respectively (D308394, T. Bloem, 30-Nov-05).  Based on the recommended almond hull and citrus tolerances (0.04 ppm), the maximum contribution of almond hulls and/or dried citrus pulp to the beef/dairy cattle diet is 0.008 ppm.  Therefore, the previous conclusions concerning the residues of concern in ruminants remain appropriate.  

The metabolites M320I04, M320I23, and M320I28 are not considered to cause greater toxicity than parent (metaflumizone) or toxicity other than the parent compound.  M320I04 lacks the T-ring, which is thought to drive the toxicity for metaflumizone.  M320I23 and M320I28 contain the T-ring; however, they do not contain any additional functionalities that would enhance their toxicity above that of parent.  It is noted that the cotton (PHI = 21 days) and tomato (PHI = 0 and 7 days) metabolism studies and the environmental degradation studies indicated that selective metabolism and/or isomerization resulted in E:Z metaflumizone isomer ratios of ~1:1 (cotton and tomato) and 1.7:1 (environmental degradation).  However, as stated in Section 3.2, HED concludes that the Z-isomer, even when enriched to 100%, is of lesser toxicity than metaflumizone technical, and, therefore, the toxicological studies performed with the technical product (E:Z of >90%:10%) are protective of any potential enrichment of the Z-isomer.

HED notes the initial metaflumizone human-health risk assessment (D304496, R. Mitkus et al., 24-Jan-2006) indicated that metaflumizone (E and Z isomers) and M320I23 were the residues of concern in drinking water and EFED provided estimated drinking water concentrations (EDWCs) for these compounds (D319414, M. Ruhman, 13-Mar-2006).  Subsequent EDWC memorandum from EFED provided concentrations for parent only and noted that previously a conservative approach was taken by modeling parent plus M320I23.  The environmental degradation section of the above referenced human-health risk assessment (Section 5.1.4) indicated the following:  "...due to their low concentrations and slow formation, the environmental degradates of metaflumizone are not expected to be threats to surface water".  Based on this and since the groundwater EDWC for combined parent and M320I23 was orders of magnitude lower than that for surface water, HED concludes that EDWCs representing parent only are acceptable.  

Table 4.1.1:  Residues of Concern for Tolerance Expression and Risk Assessment (see Appendix B.6 for structures).
                                    Matrix
                     Residues included in Risk Assessment
                   Residues included in Tolerance Expression
Plants[1]
metaflumizone (E and Z isomers) and M320I04
metaflumizone (E and Z isomers) and M320I04
Livestock (excluding ruminant liver)[2]
metaflumizone (E and Z isomers)
metaflumizone (E and Z isomers)
Livestock ruminant liver[2]
metaflumizone (E and Z isomers) and M320I28[3]
metaflumizone (E and Z isomers)
Rotational crops
metaflumizone (E and Z isomers) and M320I04
metaflumizone (E and Z isomers) and M320I04
Drinking water
metaflumizone (E and Z isomers) 
Not applicable
1  This decision is contingent on the petitioner submitting data which address the following: (1) cabbage metabolism study - information pertaining to sample extraction and analysis dates; if the interval is > currently validated interval, then additional storage stability data are required; (2) cotton metabolism study - individual concentrations of the unknowns is needed; if any unknown comprises >10% of the TRR, then further characterization/identification procedures may be required (based on these data additional residues may be included for risk assessment).
2  For future petitions, these conclusions will be re-evaluated; see Section 5.1.6 of D304496 (R. Mitkus et al., 24-Jan-2006).
3  Acetonitrile and acetic acid microwave extraction of the methanol extracted liver residues results in the formation of M320I28 (microwave assisted cleavage and/or derivatization; common moiety method).

4.2 Analytical Methodology

HED previously determined that the BASF liquid chromatography/mass spectrometer/mass spectrometer (LC/MS/MS) Method 531/0 is adequate for tolerance enforcement and forwarded this method to the Food and Drug Administration (FDA; D308394, T. Bloem, 30-Nov-05; D328915, T. Bloem, 17-May-06).  Citrus, grape, and tree nut samples from the field trial and processing studies were analyzed for residues of metaflumizone (E and Z isomers; limit of quantitation (LOQ) = 0.01 ppm) and M320I04 (LOQ = 0.018 ppm) using BASF method 531/0.  Based on the adequate validation data submitted with the field trial and processing studies, HED concludes that the current enforcement method is suitable for enforcement of the tolerances associated with the current petition.  

4.3 Comparative Metabolic Profile

M320I04 (all structures found in Appendix B) is the only metabolite that is common to plants, livestock (hen and goat), and the rat.  In plants, it appears that metaflumizone is metabolized by way of the following reactions: isomerization of the metaflumizone E isomer to the Z isomer (cotton, tomato); ring closure to form metabolite M320I23 (circular parent; in cotton, tomato, and cabbage); cleavage of metaflumizone at the imine bridge, resulting in the formation of M320I04 and a metabolite containing the p-trifluoromethoxyaniline moiety (cotton, tomato, cabbage, and rotational crops); cleavage of M320I23 to form M320I05 (p-trifluoromethoxyaniline; cotton); and cleavage of M320I23 and/or M320I04 to form M320I06 (4-cyanobenzoic acid; cotton, tomato, and cabbage).

Metabolites M320I04/25/26/27 are common to both hen and goat.  In hen, it appears that metaflumizone is metabolized via the following reactions: hydroxylation of metaflumizone at the 3-trifluoromethylphenyl ring to form M320I27; formation of M320I04 and a metabolite containing the p-trifluoromethoxyaniline moiety (as in plants); and/or reduction of M320I04 to form M320I25, which is conjugated with glutamic acid to form M320I26.  In goat, metabolism of metaflumizone appears to occur in the following manner: hydroxylation of metaflumizone at the trifluoromethoxyaniline ring forming M320I22 followed by conjugation to glucuronic acid to form M320I24; hydroxylation of metaflumizone at the benzyl position to form M320I07 followed by oxidation and ring formation yielding M320I23; formation of M320I04 and a metabolite containing the p-trifluoromethoxyaniline moiety (as in plants and hen); cleavage of M320I04 to form M320I06, which is conjugated with glycine to form M320I13; and/or reduction of M320I04 to form M320I25, which is conjugated with glucuronic acid to form M320I10 or conjugated with glutamic acid to form M320I26.  The petitioner isolated and identified M320I17 (trifluoromethoxyaniline derivative) as a major residue in urine (53% TRR), which indicates that free T-ring compounds are forming in significant concentrations.

In the rat, metaflumizone is thought to be metabolized by several pathways.  M320I04 (plus the p-trifluoromethoxyaniline moiety) is formed in a similar manner as in plants and livestock.  M320I04 is then further metabolized to M320I06 and then M320I13 and/or M320I10 (without M320I25 intermediate), as in goat.  M320I05 is also formed from parent, as in cotton, but in one step (without cyclization).  M320I23 (circular parent) is not formed in the rat as it is in certain plants and goat.  Two metabolites were measured in the rat that were also found in goat (M320I07/17).  Metabolites that were unique to the rat included M320I21 (trifluoromethoxyaniline derivative conjugated to glutathione and glucuronic acid), M320I12 (product conjugated to glutathione and glucuronic acid after T-ring cleavage), and M320I16 (trifluoromethoxyurea derivative).

4.4 Drinking Water Residue Profile

Metaflumizone has a low vapor pressure (9.30 x 10[-11] torr) and very low solubility in water (solubility 1.79 ppb at 20[o]C).  Metaflumizone was practically stable to aqueous hydrolysis in neutral and alkaline conditions and to photolysis on soil (predicted environmental soil photolysis half-life of 54 days).  It has also shown the same stability to metabolism in the aerobic soil system (the 90[th] percentile half-life of 134 days), and the anaerobic aquatic water/sediment systems (half-life of >378 days).  In field studies, metaflumizone has shown similar persistence in planted terrestrial field studies (half-life of 6-24 days in bare-ground plots and 174-618 days in plots planted with cotton and potatoes).  In contrast, relatively low persistence was observed in highly acidic aqueous systems or in aqueous systems exposed to light energy (half-lives of 5-29 days).  For mobility, metaflumizone appears to have very high affinity to soil and sediment particles rendering it to be immobile in systems with varied textures and organic matter content (Koc of 16,534-51,031 L Kg[-1]).  The chemical is not expected to partition into the air due to its very low vapor pressure.

EFED provided surface and ground estimated drinking water concentrations generated using the Screening Concentration in Groundwater (SCI-GROW) and Pesticide Root Zone Model - Exposure Analysis Modeling System (PRZM-EXAMS) models, respectively ( D367556, J. Meléndez, 3-Aug-2011).  The models were run using the fly bait application scenario to turf to represent application to use sites such as recreational facilities and outdoor recreational areas including parks, picnic grounds, and camp grounds (26 x 0.0137 lb ai/acre; yielded the highest EDWCs).  The SCI-GROW model resulted in a point estimate of 2.14 x 10[-3] ppb and the PRZM-EXAMS model resulted in peak residue of 1.14 ppb and a 1-in-10 year annual mean concentration of 0.597 ppb for residues of metaflumizone (E and Z isomers).  Therefore, the acute and chronic dietary exposure analyses assumed a drinking water estimate of 1.14 ppb and 0.597ppb, respectively.  

4.5 Food Residue Profile

Granular Fly Bait Application:  The proposed granular fly bait application scenario does permit application in and around food handling establishments and agricultural structures and premises including inside livestock premises.  However, the labels include the following restrictions:  Do not apply in areas where livestock can ingest or contact the bait and do not use (except for bait station use) in edible product areas where food is commercially prepared or processed or in serving areas when food is exposed.  Considering these restrictions and since metaflumizone has a low vapor pressure (1.24 x 10[-8] Pa at 20 ºC), HED concludes that this use will not result in significant residues in/on food/feed.  

Citrus, Grape, Tree Nuts, and Non-Bearing Stone and Pome Fruit Trees:  The submitted citrus fruit, grape, and tree nut magnitude of the residue studies are adequate pending submission of supporting storage stability data.  Residues of metaflumizone (E and Z isomers) and M320I04 were <LOQ (limit of quantitation) in/on all samples of citrus fruit, grape, tree nutmeat, and almond hulls harvested 5 days following a single soil application of the test formulation at 0.004 lb ai/acre (4x/1x the maximum proposed single/seasonal application rate).  The submitted data will support tolerances for the combined residues of metaflumizone (E and Z isomers) and the metabolite M320I04 (expressed as parent) in/on citrus fruit, grape, tree nuts, and almond hulls at the combined LOQ of 0.04 ppm.  A revised Section F is requested.

The submitted grape and orange processing studies are adequate pending submission of supporting storage stability data.  Residues of metaflumizone (E and Z isomers) and M320I04 were <LOQ in/on the orange and grape raw agricultural commodity (RAC) and orange oil following application at 5x the proposed rate.  Processing data for the grape processed commodities and the remaining orange processed commodities were not provided and are unnecessary since residues were <LOQ in/on the RAC following treatment at 5x.  The data indicate that no tolerances are needed for the processed commodities of grape or citrus fruit.  

Based on the submitted residue data and low application rate, HED concludes that application to non-bearing stone and pome fruit trees may be considered a non-food use (application within 1 year of harvest is prohibited).

Livestock:  Considering the proposed/registered uses, the only feedstuffs are almond hulls and dried citrus pulp, which may be fed to cattle (no poultry or hog feed commodities).  Using the revised OPPTS 860.1000 Table 1, the maximum reasonably balanced diet (MRBD) for beef and dairy cattle is 0.004 ppm; based on these dietary burdens and the previously reviewed cattle feeding study (D308394, T. Bloem, 30-Nov-05), HED concludes that livestock tolerances are unnecessary.

Rotational Crops:  Citrus fruits, grapes, and tree nuts are typically not rotated; therefore, data pertaining to rotational crops are not required to support the proposed uses.

4.6 International Residue Limits and HED-Recommended Tolerances

There are no Canadian, Mexican, or Codex Maximum Residue Limits (MRLs) established for residues of metaflumizone; therefore, harmonization is not relevant.  HED requests that the petitioner submit a revised Section F specifying the commodity definitions and numerical tolerances specified in Table 5.6.1 and the following tolerance definition:  

   Tolerances are established for residues of the insecticide metaflumizone, including its metabolites and degradates, in or on the commodities in the table below.  Compliance with the tolerance levels specified below is to be determined by measuring only the sum of metaflumizone (E and Z isomers; 2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl) phenyl]ethylidene]-N-[4-(trifluoromethoxy)phenyl] hydrazinecarboxamide) and its metabolite 4-{2-oxo-2-[3-(trifluoromethyl) phenyl]ethyl}-benzonitrile, calculated as the stoichiometric equivalent of metaflumizone, in or on the following commodities:  

Table 4.6.1:  Tolerance Summary for Metaflumizone.
                                   Proposed
                                HED-Recommended
                                   Comments
                                   Commodity
                                Tolerance (ppm)
                             Commodity Definition
                                Tolerance (ppm)
                                       
Citrus Fruits, Group 10
                                     0.01
Fruit, citrus, group 10
                                     0.04
Based on the field trial data, a higher tolerance is required.
Tree Nuts, Group 14
                                     0.01
Nut, tree, group 14
                                     0.04

Grapes, table
                                     0.01
Grape
                                     0.04

Grapes, wine
                                     0.01
                                      --
                                     none
Based on the processing data, a separate tolerance for wine is not required.
Almond, hulls
                                     none
Almond, hulls
                                     0.04
Based on the field trial data, a tolerance is required.

4.7 Dietary Exposure and Risk

Acute and chronic metaflumizone dietary risk assessments were conducted using DEEM-FCID (ver. 2.03) model.  DEEM-FCID(TM) (ver. 2.03) incorporates consumption data from the USDA CSFII (1994-1996 and 1998).  The acute and chronic dietary analyses assumed tolerance-level residues, 100% crop treated, and modeled drinking water estimates from the Pesticide Root Zone Model-Exposure Analysis Modeling System (PRZM-EXAMS).  The drinking water estimates were based on the application of metaflumizone as a fly bait on use sites such as recreational facilities and outdoor recreational areas including parks, picnic grounds, and camp grounds represented by the turf modeling scenario [this scenario resulted in the highest estimated drinking water concentration (EDWC)].  DEEM(TM) (ver. 7.81) default processing factors were assumed for all commodities excluding grape raisin, grape juice, and citrus juice, which were reduced to 1 based on empirical data.  The acute dietary exposure estimate for females 13-49 years old was <1% the aPAD and, therefore, does not exceed HED's LOC.  An endpoint attributable to a single dose was not identified for the remaining population subgroups.  The chronic dietary exposure estimates were 1% the cPAD and, therefore, do not exceed HED's LOC (children 1-2 years old were the most highly exposed population subgroup).  Table 4.7.1 is a summary of the acute and chronic dietary exposure estimates for the various populations. 

Table 4.7.1.  Summary of Acute and Chronic Dietary Exposure and Risk for Metaflumizone (drinking water included).
Population Subgroup
                                     Acute
                                    Chronic

                               aPAD (mg/kg/day)
                             Exposure (mg/kg/day)
                                     %aPAD
                               cPAD (mg/kg/day)
                             Exposure (mg/kg/day)
                                     %cPAD
General U.S. Population
                            no endpoint identified
                                     0.04
                                   0.000092
                                    <1.0
All Infants (< 1 year old)
                                       
                                       
                                   0.000102
                                    <1.0
Children 1-2 years old
                                       
                                       
                                   0.000323
                                    <1.0
Children 3-5 years old
                                       
                                       
                                   0.000239
                                    <1.0
Children 6-12 years old
                                       
                                       
                                   0.000132
                                    <1.0
Youth 13-19 years old
                                       
                                       
                                   0.000079
                                    <1.0
Adults 20-49 years old
                                       
                                       
                                   0.000066
                                    <1.0
Adults 50+ years old
                                       
                                       
                                   0.000071
                                    <1.0
Females 13-49 years old
                                     0.33
                                   0.000329
                                    <1.0
                                       
                                   0.000071
                                    <1.0

5.0 Residential Exposure/Risk Characterization
D393548, K. Lowe, 20-Sep-11
D393547, K. Lowe, 20-Sep-11

The proposed fire ant bait product (citrus fruit, grapes, and tree nuts) is not expected to result in residential exposure since the proposed use sites are agricultural sites.  Note: The proposed use as an agricultural fire ant bait was previously assessed (D367561, M. Dow, 07-Dec-09), but revisions have been made to account for the revisions to the hazard assessment of metaflumizone (D393547, K. Lowe, 20-Sep-11).  

The proposed fly bait product can be used in areas where children could be present and, therefore, a residential assessment was performed for this use.  
 
There are already registered fire ant bait uses (lawns, landscapes, golf courses, and other non-cropland) and pet uses (spot-on product) that would result in residential exposure that have been previously assessed (D345154, T. Bloem et al., 26-Jan-2010; D315785, M. Dow, 19-Jan-2006).  The pet use product is in the process of being cancelled; however, it has been included in this assessment.  Existing product will continue to be sold; but the registration will not be maintained past 2012.
   
5.1 Residential Handler Exposure

Fly Bait (proposed): The proposed product is not anticipated to result in non-occupational use as it is proposed for commercial/recreational areas such as campgrounds and picnic grounds.  It is expected that commercial handlers would apply this product to areas such as these.  Therefore, a residential handler assessment has not been performed for the proposed fly bait product.

Fire Ant Bait (registered on lawns, landscapes, golf courses, and other non-cropland):  Residential handler exposure was expected for homeowners who may apply the registered fire ant bait product to home lawns.  Since the residential and commercial fire ant products have identical application rates, HED used the commercial loader/applicator dermal (no gloves) and inhalation exposure assumptions to calculate exposure and risk estimates for the homeowner loader/applicator scenario (commercial push-type drop spreader; 5 acres/day; only short-term exposures anticipated).  Risks were not a concern for residential handlers (i.e., MOEs > the LOC of 100 for dermal exposures and 1000 for inhalation exposures; see Table 4.4).

Pet Care (registered spot-on product):  Residential handler exposure/risk from metaflumizone application to domestic pets was not assessed because handler contact is expected to be negligible.  The spot-on product is designed to be self-contained as it is applied directly from the tube to the pet with the tip of the applicator used to part the pet's hair.  

5.2 Residential Post-application Exposure

Fly Bait (proposed):  The proposed fly bait product can be used in areas where adults and children could be present, such as campgrounds and picnic grounds.  For adults, dermal exposure was assessed and for children (3 to <6 year olds), dermal and incidental oral exposure (e.g., hand-to-mouth exposure) was assessed for individuals contacting turf or soil treated with fly bait granules.  Short-term dermal and incidental oral exposures/risks have been assessed here and since the short- and intermediate-term PODs are the same, the short-term assessment is protective of longer-term exposures.  In addition, the fly bait product is a granular product and; therefore, ingestion of metaflumizone granules found in treated turf is also a potential source of exposure for children.  This scenario is considered an episodic event by HED and, therefore, is assessed as an acute exposure (i.e., acute dietary endpoints are used).  Since there is no acute dietary endpoint applicable to children, no quantitative assessment was needed.  The resulting dermal and incidental oral MOEs were greater than the LOCs of 100 and 300, respectively, and, therefore, were not of concern (see Table 6.4.1).  

Fire Ant Bait (registered on lawns, landscapes, golf courses, and other non-cropland):  Use of the fire ant bait products may result in short-term post-application exposure to children (3 to <6 year olds; dermal and incidental oral), adults (dermal), and adolescents (dermal) contacting treated turf.  As stated above, short-term exposures are expected; however, since the short- and intermediate-term PODs are the same, the short-term risk estimates are protective of any potential intermediate-term exposures.  Ingestion of metaflumizone granules found in treated lawns is also a potential source of exposure for children.  This scenario is considered an episodic event by HED and, therefore, is assessed as an acute exposure (i.e., acute dietary endpoints are used).  Since there is no acute dietary endpoint applicable to children, no quantitative assessment was needed.  The resulting dermal and incidental oral MOEs were greater than the LOCs of 100 and 300, respectively, and, therefore, were not of concern (see Table 6.4.1).  

Pet Care (registered spot-on product):  As mentioned above, the pet care products registered for metaflumizone are in the process of being cancelled; however, the uses have been included in this risk assessment.  The pet care products may result in short- and intermediate-term post-application dermal (all populations) and incidental oral [children (3 to<6 year olds)] exposures.  The resulting MOEs are >100 for dermal exposure and >300 for incidental oral exposures and, therefore, exceed HED's LOC (see Table 6.4.1).  HED notes that pet care product exposure calculations can be considered refined in that they are based on the assumptions that 0.78% of the application rate is available as dislodgeable residue rather than the default 20%; for further information see D315785 (M. Dow, 19-Jan-06).

5.3 Combined Residential Exposure

For residential handlers, dermal and inhalation exposures are combined since the endpoints are similar for these routes.  For children (3 to <6 year olds), post-application hand-to-mouth and dermal exposures are combined.  Dermal exposure could be combined with all the incidental oral exposure scenarios (e.g., hand-to-mouth, object-to-mouth, soil ingestion) since it is assumed that these exposures do not occur as single, isolated events, but rather as a series of concurrent events that may overlap.  However, combining all of the incidental oral exposures with dermal exposure would be overly conservative because each of these scenarios, independently, incorporates high-end, health protective inputs or assumptions.  Combining post-application dermal exposure with only hand-to-mouth exposure is considered a protective estimate of children's exposure to pesticides used in residential settings.

Since the LOCs for the dermal, inhalation and incidental oral routes are not the same (dermal LOC = 100, inhalation LOC = 1000, and incidental oral LOC = 300), these routes were combined using the ARI approach.  All of the combined risk estimates are greater than the LOC and, therefore, are not of concern.

Table 5.3.1.  Summary of Short-term Residential Handler and Post-application Exposures and Risks.
Population
Route of Exposure
Dose (mg/kg/day)
MOE[1]
Fire Ant Bait (registered on lawns, landscapes, golf courses, and other non-cropland; D345154/D315785)
Adult -- Residential Handler
Dermal
0.00021
480,000

Inhalation
0.00000045
18,000,000

Combined dermal and inhalation
--
ARI2 = 3,800
Adult  -  Residential Post-application
Dermal
0.000232
430,000
Adult  -  Golfer Post-application
Dermal
0.000016
6,200,000
Adolescent  -  Golfer Post-application
Dermal
0.0000272
3,700,000
Children (3 to <6 year olds)  -  
Post-application
Incidental oral hand-to-mouth
0.000015
1,300,000

Incidental oral object-to-mouth
0.00000093
22,000,000

Dermal
0.00039
260,000

Combined incidental oral hand-to-mouth and dermal
--
ARI3 = 1,600
Pet Care (registered spot-on; D345154/D315785)
Adults  -  Post-application 
Dermal
0.29
340
Children (3 to <6 year olds)  -  
Post-application 
Incidental oral hand-to-mouth
0.035
570

Dermal
0.16
620

Combined incidental oral hand-to-mouth and dermal
--
ARI3 = 1.5
Fly Bait (proposed; D393548)
Adult  - Post-application
Dermal
0.0033
31,000
Children (3 to <6 year olds)  -  
Post-application
Incidental oral hand-to-mouth
0.00021
96,000

Incidental oral object-to-mouth
0.000052
380,000

Incidental soil ingestion
0.0000007
29,000,000

Dermal
0.0054
18,000

Combined incidental oral hand-to-mouth and dermal
--
ARI3 = 120
1.	MOE = NOAEL (mg/kg/day) / Dose (mg/kg/day). 
2.	ARI = Aggregate Risk Index = 1 / ((1 / (MOEinhalation / LOCinhalation)) + (1 / (MOEdermal / LOCdermal))); ARI > 1 indicates an acceptable 	exposure. 
3.	ARI = Aggregate Risk Index = 1 / ((1 / (MOEincidental oral hand-to-mouth / LOCincidental oral hand-to-mouth)) + (1 / (MOEdermal / LOCdermal))); ARI > 1 indicates an acceptable exposure.

6.0 Aggregate Risk Assessments and Risk Characterization
 
 In accordance with the FQPA, HED must consider and aggregate pesticide exposures and risks from dietary (food and water) and residential (dermal, inhalation, incidental oral) sources.  When aggregating exposures and risks from these sources, HED considers the route and duration of exposure as well as the toxicological effects for each route.  As indicated above, short-/intermediate-term dermal, oral, and inhalation exposures can be aggregated based on a common toxic effect (decreased body weight or decreased body-weight gain).  Based on this and the proposed/registered uses, aggregate acute, short-/intermediate-term, and chronic assessments were conducted.  
 
6.1 Acute Aggregate Risk

Since there are no registered/proposed uses that result in acute residential exposure to females 13-49 years old (acute endpoint was not identified for the remaining populations), the acute aggregate exposure assessment consists of exposure from only food and water.  The acute dietary exposure estimate for females 13-49 years old was <1% the aPAD and, therefore, does not exceed HED's LOC (see Section 5.2).  

6.2 Short-/Intermediate- Term Aggregate Risk
 
The short-term aggregate assessment combines food and drinking water exposure with the highest potential residential exposure.  As seen in table 6.3.1, the pet care products result in the highest potential residential exposure estimates, with the fly bait products resulting in the second highest.  Because the pet uses of metaflumizone are in the process of being cancelled, a short-term aggregate assessment was performed both for the pet care product and for the fly bait product.  Intermediate-term exposures are possible for the pet care product; however, since the points of departure for the short- and intermediate-term durations are the same for metaflumizone, the short-term aggregate assessment is protective of longer-term exposures for the pet care product. 

For adults and the general U.S. population, the short- and intermediate-term aggregate assessments combine chronic dietary with residential post-application dermal exposure.  For young children, the short-and intermediate-term aggregate assessments combine chronic dietary exposure with incidental oral and dermal post-application exposure.  HED uses chronic dietary exposure when conducting short- and intermediate-term aggregate assessments since it has been determined that these will more accurately reflect exposure from food over the HED defined short- and intermediate-term interval than will acute exposure.  
 
Table 6.2.1 is a summary of the short-term and intermediate-term aggregate risk estimates resulting from the fly bait product and the pet care product.  Since the LOCs for the dermal and oral routes are not the same (dermal LOC = 100 and oral LOC = 300), these routes were combined using the ARI approach.  The aggregate ARIs are >1; therefore, none of the calculated short- and intermediate-term aggregate risks are of concern.   

Table 6.2.1:  Short- and Intermediate-Term Aggregate Risk
Population
                Background Dietary + Incidental Oral Exposures
                             Residential Exposures
                                     ARI 
                       (food, water, and residential)[f]

                                   Oral LOC
                Chronic Food and Water Exposure (mg/kg/day)[a]
                    Incidental Oral Exposure (mg/kg/day)[b]
                                  Oral MOE[c]
                                  Dermal LOC
                        Dermal Exposure (mg/kg/day)[d]
                                 Dermal MOE[e]
                                       
Pet Care Product (Short and Intermediate-term)
General U.S. Population
                                      300
                                    0.00008
                                      NA
                                    250,000
                                      100
                                     0.29
                                      340
                                       3
Children 1-2 years old
                                       
                                    0.00031
                                     0.035
                                      570
                                       
                                     0.16
                                      620
                                       2
Fly Bait Product (Short-term)
General U.S. Population
                                      300
                                    0.00008
                                      NA
                                    250,000
                                      100
                                    0.0033
                                    31,000
                                      230
Children 1-2 years old
                                       
                                    0.00031
                                    0.00021
                                    39,000
                                       
                                    0.0054
                                    18,000
                                      75
a. See Table 5.7.1 for exposures.
b. See Table 6.3.1 for exposures.  Incidental oral exposure only represents hand-to-mouth exposure for purposes of the aggregate assessment.  
c. Oral MOE = NOAEL (20 mg/kg/day) / (chronic food/water exposure + incidental oral exposure).
d. See Table 6.3.1 for exposures.
e. Dermal MOE = NOAEL (100 mg/kg/day) / (dermal exposure).
f. ARI (Aggregate Risk Index) = 1 / ((1 / (Oral MOE / Oral LOC)) + (1 / (Dermal MOE / Dermal LOC))); ARI > 1 indicates an acceptable exposure.

6.3 Chronic Aggregate Risk

Since there are no registered/proposed uses that result in chronic residential exposure, the chronic aggregate exposure assessment consists of exposure from food and water.  The chronic dietary exposure estimate was <=1% the cPAD and, therefore, does not exceed HED's LOC (see Section 5.2).  

6.4 Cancer Aggregate Risk

An aggregate cancer risk assessment was not performed because metaflumizone is not considered to be a carcinogen.  

7.0 Cumulative Risk Characterization/Assessment

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 for metaflumizone and any other substances; and metaflumizone does not appear to produce a toxic metabolite produced by other substances.  For the purposes of this tolerance action, therefore, EPA has assumed that metaflumizone does not have 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/.

8.0 Occupational Exposure/Risk Characterization
D393547, K. Lowe, 20-Sep-11
D393548, K. Lowe, 20-Sep-11

There are two proposed products that may result in occupational handler and post-application exposure:  (1) Metaflumizone Fly Bait for use around industrial buildings, commercial facilities, agricultural structures and premises, recreational facilities and outdoor recreational areas; and (2) Altrevin Fire Ant Bait Insecticide for use as a soil treatment in citrus orchards, tree nut orchards, grape vineyards, nonbearing stone and pome fruit orchards and in nurseries containing nonbearing container- or field-grown stone and pome fruit tree stock.

Note:  The proposed use as an agricultural fire ant bait was previously assessed (D367561, M. Dow, 07-Dec-09), but revisions have been made to account for the revisions to the FQPA SF (D393547, K. Lowe, 20-Sep-11).

8.1 Occupational Handler Exposure

The proposed products are both solid bait formulations.  Metaflumizone Fly Bait is to be used as a scatter bait for broadcast treatment or placed in bait stations/trays.  Altrevin Fire Ant Bait Insecticide can be used for broadcast and individual mound applications.  

Dermal and inhalation exposures/risks were estimated for handlers involved in mixing/loading activities for granular formulations for tractor-drawn spreader equipment, applying granulars via tractor-drawn spreader or by hand, and mixing/loading/applying activities for handheld equipment, such as push-type spreaders, belly grinders and spoons.  The metaflumizone product labels require long-sleeved shirt and long pants and chemical-resistant gloves as dermal PPE for all applicators and other handlers.  

No chemical-specific handler exposure data were submitted in support of this Section 3 registration.  To assess handler exposures for regulatory actions when chemical-specific monitoring data are not available, HED relies on the most scientifically reliable surrogate data currently available from various sources such as PHED, AHETF, and ORETF.  Some of this data, such as the industry task force data, is compensatory, subject to the data protection provisions of FIFRA.  HED policy on use of surrogate data is described in more detail on the Agency's website (http://www.epa.gov/pesticides/science/handler-exposure-data.html).  Scenario-specific surrogate exposure data, including their sources, are presented in the "Occupational Pesticide Handler Unit Exposure Surrogate Reference Table" (http://www.epa.gov/pesticides/science/handler-exposure-table.pdf).    

Typically, HED completes short- and intermediate-term assessments for occupational scenarios in all cases because these kinds of exposures are likely and acceptable use/usage data are not available to justify deleting intermediate-term scenarios.  Based on use data and label instructions, HED believes that occupational exposures may occur over a single day or up to weeks at a time for many use-patterns and that intermittent exposure over several weeks may also occur.  Some applicators may apply these products over a period of weeks, because they are commercial applicators who are completing multiple applications for multiple clients.  Long-term exposures are not expected, therefore, a long-term assessment was not conducted.  

Dermal and inhalation risks were combined in this assessment, since the toxicological effects for these exposure routes were similar.  A total ARI was used since the LOCs for dermal exposure (100) and inhalation exposure (1000) are different.  The target ARI is 1; therefore, ARIs of less than 1 are risks of concern.  

Table 8.1.1 presents the exposure/risks for short- and intermediate-term dermal and inhalation exposures at baseline and with gloves.  The dermal and inhalation exposure risks for mixer/loaders, applicators and mixer/loader/applicators are not of concern (i.e., MOEs >100 for dermal and >1000 for inhalation; ARIs >1) at baseline and with the addition of gloves.  

Table 8.1.1.  Short-/Intermediate-Term Occupational Exposure and Risk Estimates for Metaflumizone.  
Exposure Scenario
Use Site
Mitigation[1]
Dermal Unit Exposure
(ug/lb ai)[2]
Inhalation Unit Exposure
(ug/lb ai)[2]
Application Rate[3]
Amount Treated Daily[4]
Dermal
Inhalation
ARI[9]







Dose
(mg/kg/day)[5]
MOE[6]
Dose
(mg/kg/day)[7]
MOE[8]

MIXER/LOADER
Mixing / Loading Granules for Tractor Drawn Spreader Applications
Fire Ant Bait
Baseline
8.4
1.7
0.001 lb ai/acre
40 acres
0.0000048
21,000,000
9.70E-07
8,200,000
7,900


PPE-G
6.9
NA


0.0000039
25,000,000
NA
NA
35,000

Fly Bait
Baseline
8.4
1.7
0.014 lb ai/acre
40 acres
0.000067
1,500,000
1.40E-05
590,000
570


PPE-G
6.9
NA


0.000055
1,800,000
NA
NA
2,500
APPLICATOR
Applying Granules via Tractor Drawn Spreader
Fire Ant Bait
Baseline
9.9
1.2
0.001 lb ai/acre
40 acres
0.0000057
18,000,000
6.90E-07
12,000,000
11,000


PPE-G
7.2
NA


0.0000041
24,000,000
NA
NA
47,000

Fly Bait
Baseline
9.9
1.2
0.014 lb ai/acre
40 acres
0.000079
1,300,000
9.60E-06
830,000
780


PPE-G
7.2
NA


0.000058
1,700,000
NA
NA
3,400
Applying Granules by Hand
Fire Ant Bait
Baseline
104000
470
0.000078 lb ai/mound
5 mounds
0.00058
170,000
2.60E-06
3,100,000
1,100


PPE-G
71000
NA


0.0004
250,000
NA
NA
2,100

Fly Bait
Baseline
104000
470
0.017 lb ai/acre
0.5 acre
0.013
7,900
5.70E-05
140,000
51


PPE-G
71000
NA


0.0086
12,000
NA
NA
100
MIXER/LOADER/APPLICATOR
Mixing / Loading/Applying Granulars via "Push Type" Rotary Spreader
Fire Ant Bait
Baseline
440
10
0.001 lb ai/acre
5 acres
0.000031
3,200,000
7.10E-07
11,000,000
8,200


PPE-G
240
NA


0.000017
5,800,000
NA
NA
28,000

Fly Bait
Baseline
440
10
0.014 lb ai/acre
5 acres
0.00044
230,000
1.00E-05
800,000
590


PPE-G
240
NA


0.00024
420,000
NA
NA
2,000
Applying Ready to Use Granular by Spoon (MRID #452507-01; Fipronil study)
Fire Ant Bait
Baseline
No Data
45
0.000078 lb ai/mound
5 mounds
No Data
No Data
2.50E-07
32,000,000
No Data 


PPE-G
2000
NA


0.000011
9,000,000
NA
NA
58,000

Fly Bait
Baseline
No Data
45
0.017 lb ai/acre
0.5 acre
No Data
No Data
5.50E-06
1,500,000
No Data


PPE-G
2000
NA


0.00024
410,000
NA
NA
2,600
Mixing / Loading/Applying Granulars via Belly Grinder
Fire Ant Bait
Baseline
10000
62
0.001 lb ai/acre
1 acre
0.00014
700,000
8.90E-07
9,000,000
3,900


PPE-G
9300
NA


0.00013
750,000
NA
NA
6,400

Fly Bait
Baseline
10000
62
0.014 lb ai/acre
1 acre
0.002
50,000
1.20E-05
650,000
280


PPE-G
9300
NA


0.0019
54,000
NA
NA
460
[1] Level of mitigation: Baseline and PPE-G (gloves).  Gloves are recommended PPE on proposed label.
2 PHED/ORETF/AHETF 
3 Based on proposed label (Reg. No. #7969-xxx)
4 Exposure Science Advisory Council Policy #9.1
5 Dermal Dose = Dermal Unit Exposure (mg/kg) x Application Rate (lb ai/acre) x Amount Treated (acres/day) / BW (70 kg)

6 Dermal MOE = Dermal NOAEL (100 mg/kg/day) / Dermal Dose (mg/kg/day).  LOC = 100.
7 Inhalation Dose = Inhalation Unit Exposure (mg/kg) x Application Rate (lb ai/acre) x Amount Treated (acres/day) / BW (70 kg)
8 Inhalation MOE = Inhalation NOAEL (8 mg/kg/day) / Inhalation Dose (mg/kg/day).  LOC = 1000.
9 ARI (Aggregated Risk Index) = 1 / ((1 / (Dermal MOE / Dermal LOC)) + (1 / (Inhalation MOE / Inhalation LOC))).  Baseline dermal and PPE-G Dermal combined with Baseline Inhalation.

8.2 Occupational Post-application Exposure

Occupational dermal postapplication exposure was not assessed.  With regard to the fly bait use, it is not anticipated that workers will be exposed after application of the fly bait.  HED believes the presence of commercial workers in treated areas is minimal after application.  With regard to the fire ant bait use, dermal contact with treated surfaces is not expected; all applications are directed towards the soil surface.  In addition, workers are not expected to frequent areas infested with active fire ants.  For these reasons, a quantitative dermal post-application assessment has not been conducted.  

Based on the Agency's current practices, a quantitative occupational post-application inhalation exposure assessment was not performed for metaflumizone at this time.  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 (FIFRA) Scientific Advisory Panel (SAP) in December 2009.  The Agency received the SAP's final report on March 2, 2010 (http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html).  The Agency is in the process of evaluating the SAP report as well as available post-application inhalation exposure data generated by the Agricultural Reentry Task Force 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 metaflumizone. 

8.3 Restricted Entry Interval

For the fly bait product, a REI is not required since the proposed use sites are non-agricultural sites.  For the fire ant bait (citrus fruit, grapes, and tree nuts), a REI is required on the label and the draft label lists a 12-hour REI.  Metaflumizone is classified in Acute Toxicity Category IV for acute dermal toxicity, acute inhalation toxicity, primary eye irritation, primary dermal irritation and it is not a dermal sensitizer.  Therefore, the interim WPS REI of 12 hours is adequate to protect agricultural workers from post-application exposures.  

9.0 Data Deficiencies

9.1 Toxicology

   * None.

9.2 Residue Chemistry

   * A revised Section B is requested which list the crops for each crop group as defined in 40 CFR 180.41 and eliminates the "including but not limited to" phrase.
   * A revised Section F with the tolerance expression, commodity definitions, and numerical tolerances described as follows:  Tolerances are established for residues of the insecticide metaflumizone, including its metabolites and degradates, in or on the commodities in the table below.  Compliance with the tolerance levels specified below is to be determined by measuring only the sum of metaflumizone (E and Z isomers; 2-[2-(4-cyanophenyl)-1-[3-(trifluoromethyl)phenyl]ethylidene]-N-[4-(trifluoromethoxy)phenyl] hydrazinecarboxamide) and its metabolite 4-{2-oxo-2-[3-(trifluoromethyl)phenyl]ethyl}-benzonitrile, calculated as the stoichiometric equivalent of metaflumizone, in or on the following commodities:  Fruit, citrus, group 10 - 0.04 ppm; Nut, tree, group 14 - 0.04 ppm; Almond, hulls - 0.04 ppm; and Grape - 0.04 ppm.  
   * Standards of the metaflumizone (E and Z isomers) and 4-{2-oxo-2-[3-(trifluoromethyl)phenyl] ethyl}-benzonitrile should be submitted to the EPA National Pesticide Standards Repository.  
   * Cabbage metabolism study (46264326.der.wpd) - Information pertaining to sample extraction and analysis dates is required; if the interval from harvest to analysis is greater than the currently validated interval, then additional storage stability data will also be necessary. 
   * Cotton metabolism study (46264324.der.wpd) - Individual concentrations of the unknowns should be reported; if any unknown comprises >10% TRR, then further characterization/ identification procedures may be required (based on these data additional residues may be included for risk assessment).  
   * Storage stability data - To support the subject field trial and processing studies, the following storage stability data are required which demonstrate the stability of metaflumizone (E and Z isomers) and M320I04:  grapes - 4.8 months; citrus fruit - 5.6 months; almond hulls - 6.5 months; and almond nutmeat - 5.8 months.  

9.3 Occupational and Residential Exposure

   * None.



Appendix A.  Toxicity Profile Tables

Table A.1:  Acute Toxicity Profile - Metaflumizone Technical (96% ai), Z-isomer, and Metabolite M320I23.
                           Guideline No./Study Type
                                   MRID No.
                                    Results
                               Toxicity Category
                       Metaflumizone Technical (96% ai)
870.1100/Acute oral toxicity rat
                                   46264232
LD50 => 5,000 mg/kg (males, females combined)
                                      IV
870.1100/Acute oral toxicity mouse
                                   46264234
LD50 => 5,000 mg/kg (males, females combined)
                                      IV
870.1200/Acute dermal toxicity rat
                                   46264235
LD50 > 5,000 mg/kg (males, females combined)
                                      IV
870.1300/Acute inhalation toxicity rat
                                   46264236
LC50 > 5.2 mg/L (males, females combined)
                                      IV
870.2400/Primary eye irritation rabbit
                                   46264238
Conjunctivitis in 2/3, 1/3, 0/3 at 1, 24, and 48 hours, resp.; no positive effects
                                      IV
870.2500/Primary dermal irritation rabbit
                                   46264237
non-irritant PII = 0
                                      IV
870.2600/Dermal sensitization guinea pig
                                   46264239
is not a sensitizer
                                      N/A
                                   Z-isomer
870.1100/Acute oral toxicity rat
                                   46264231
LD50 => 5,000 mg/kg (males, females combined)
                                      IV
                              Metabolite M320I23
870.1100/Acute oral toxicity rat
                                   46264233
LD50 => 2,000 mg/kg (HDT[1]) (females)
                                      III
[1] HDT=Highest Dose Tested 

Table A.2:  Subchronic and Chronic Toxicity and Genotoxicity Profile  -  Metaflumizone Technical, Z-isomer, and Metabolite M320I23.
                                Guideline No./
                                  Study Type
                     MRID No. (Year)/Doses/ Classification
                                    Results
                            Metaflumizone Technical
4-day palatability rats 
(Alternate-day feeding regimen)
47036907 (2007)

Unacceptable/non-guideline
(individual animal data not submitted)
Reduced food consumption and corresponding body weight losses occurred when treated diet was offered compared to control diet, indicating poor palatability of the diet when the test material is incorporated as an admixture in feed.
5-day palatability rats 
(Free-choice regimen)
47036908 (2007)

Unacceptable/non-guideline
(individual animal data not submitted)
When offered a choice of control feed or diet treated with 400 ppm of the test material, rats exhibited a strong preference for the control feed by avoidance of the treated diet.  This avoidance indicates poor palatability of the diet when the test material is incorporated as an admixture in feed.
7-day rats (gavage)
47036909 (2007)

0, 6, 16, or 28 mg/kg bw/day

Unacceptable/non-guideline
(individual animal and dose analysis data not submitted)
No effects on food consumption or body-weight gain.  In contrast, significant decreases in food consumption and body-weight gain were observed after 7 days of treatment at similar doses via the diet (MRID 47036902) 
90-day oral rats (dietary)
47036902 (1999/2007)

0, 50, 100, 200, or 400 ppm (equivalent to 0, 3.8, 7.2, 13.7, or 26.3 mg/kg/day)

Acceptable (non-guideline)
NOAEL not established 
LOAEL = 50 ppm (3.8 mg/kg/day) based on decreased food consumption, body weights, and body-weight gains, due to poor palatability of the test substance
28-day oral rats (dietary)
47036903 (1999/2007)

0, 10, 20, or 40 ppm (equivalent to 0, 1.1, 2.2, or 4.3 mg/kg/day)

Acceptable (non-guideline)
NOAEL = 20 ppm (2.2 mg/kg/day)
LOAEL = 40 ppm (4.3 mg/kg/day) based on decreased food consumption, body-weight gains, and body weights, due to poor palatability of the test substance
28-day oral rats (dietary)
47036904 (2000)

0, 250, 1000, 5000, or 10,000 ppm (equivalent to 0/0, 27.2/23.8, 86.4/83.2, 417.5/360.6, or 798.1/783.0 mg/kg/day [M/F]

Acceptable (non-guideline)
NOAEL not established
LOAEL = 250 ppm (27.2/23.8 mg/kg/day) based on decreased food consumption, body-weight gains, and body weights, due to poor palatability of the test substance
28-day oral mice (dietary)
47036905 (1999/2007)

0, 50, 200, or 800 ppm (equivalent to 0, 10, 42, or 101 mg/kg/day 

Acceptable (non-guideline)
NOAEL = 50 ppm (10 mg/kg/day)
LOAEL = 200 ppm (42 mg/kg/day) based on decreased food consumption, body-weight gains, and body weights, due to poor palatability of the test substance
28-day oral mice (dietary)
47036906 (2001/2007)

0, 10, 20, or 40 ppm (equivalent to 0, 2.0, 4.3, or 8.2 mg/kg/day)

Acceptable (non-guideline)
NOAEL = 40 ppm (8.2 mg/kg/day)
LOAEL not established
870.3100
90-day oral rats (gavage)
46264241 (2002)

0, 100, 500 or 1000 mg/kg/day

Unacceptable (guideline)
NOAEL (28-day) = 100 mg/kg/day  
LOAEL (28-day) = 500 mg/kg/day based on decreased BW, BW gain and food consumption, and splenic extramedullary hematopoiesis and hepatocellular hypertrophy

NOAEL (90-day) = not established
LOAEL (90-day) = not established
It is noted that treatment-related effects were not identified in either sex at 100 mg/kg/day after 90 days.
870.3250
90-day dermal rats
46264303 (2004)

0, 100, 300 or 1000 mg/kg/day

Acceptable (guideline)
NOAEL = 100 mg/kg/day
LOAEL = 300 mg/kg/day based on decreased BW gain and food consumption (M&F); anogenital smearing, decreased BW, increased macrophages in the thymus, lymphocyte necrosis in the mesenteric lymph nodes, diffuse atrophy of the mandibular lymph node, and increased hemosiderin in the liver (F)
8703465
28-day inhalation
rats 
47839301 (2004)

0, 0.03, 0.10, or 0.70 mg/L

Acceptable (non-guideline)
NOAEL= 0.03 mg/L (M) and not observed (F)
LOAEL = 0.10 mg/L based on histopathology of the nasal tissues, lungs, thymus, prostate, and adrenal cortex (M); 
and 0.03 mg/L based on lymphocyte necrosis in the mesenteric lymph node (F).  
870.3700
Developmental toxicity rats (gavage)
46264316 (2004)

0, 15, 40 or 120 mg/kg/day

Acceptable (guideline)
Maternal NOAEL = 40 mg/kg/day  
Maternal LOAEL = 120 mg/kg/day based on decreased corrected BW gain (corrected for uterine weights)

Developmental NOAEL = 120 mg/kg/day (HDT)
Developmental LOAEL > 120 mg/kg/day
870.3700
Developmental toxicity rabbits (gavage)
46264317 (2004)
0, 30, 100 or 300 mg/kg/day

Acceptable (guideline)
Maternal NOAEL = 100 mg/kg/day
Maternal LOAEL = 300 mg/kg/day based on abortions (GD 22 and 28), ataxia (GD 23-28), lateral recumbency (GD 26-29), and poor health state (GD 27-29)
Developmental  NOAEL = 100 mg/kg/day 
Developmental LOAEL = 300 mg/kg/day, based on absent subclavian artery
870.3800
2-generation reproduction rats (gavage)
46264315 (2004)

P generation: 0, 12, 30 or 75 mg/kg/day (mid and high doses reduced to 20 and 50 mg/kg/day, resp., after 17 weeks of treatment)

F1 generation: 0, 12, 20 or 50 mg/kg/day 

Acceptable (guideline)
Parental NOAEL = 20 mg/kg/day
Parental LOAEL = 50 mg/kg/day based on poor health state and decreased BW

Reproductive NOAEL = 20 mg/kg/day
Reproductive LOAEL = 50 mg/kg/day based on improper nursing behavior

Offspring NOAEL = 20 mg/kg/day
Offspring LOAEL = 50 mg/kg/day based on mortality (from birth to weaning)
870.4100
Chronic toxicity dogs (capsule)
46264302 (2004)

0, 6, 12 or 30 (60/40/30) mg/kg/day (dose level altered in high dose group)

Acceptable (guideline)
NOAEL = 12 mg/kg/day 
LOAEL = 30 mg/kg/day based on reduced general health condition, slight to severe ataxia, recumbency, and severe salivation (all clinical signs observed on >=day 191); decreases in MCHC and total Hb and increased bilirubin, increased urobilinogen, and increased hemosiderin in the liver
870.4200
Carcinogenicity
mice (gavage)
46264314 (2003)

0, 100, 250 or 1000 mg/kg/day

Acceptable (guideline)
NOAEL = 250 mg/kg/day
LOAEL = 1000 mg/kg/day (limit dose), based on incr. hemosiderin in the spleen, increased mean absolute reticulocyte count, and decreased mean corpuscular volume and mean corpuscular hemoglobin (M&F); and decreased BW gain (M).
No evidence of carcinogenicity.
870.4300
Chronic Toxicity/Carcinogenicity rats (gavage)
46264240 (2003)

0, 30, 60 or 300/200 mg/kg/day (high dose reduced to 200 mg/kg/day in females after 2 weeks of treatment)

Acceptable (guideline)
NOAEL = 30 (M) and 60 mg/kg/day (F)
LOAEL = 60 mg/kg/day based on basophilic hepatocellular alterations and hepatocellular hypertrophy (M); 200 mg/kg/day based on decreased BW, BW gain, and food consumption (F).  
No evidence of carcinogenicity.
870.5100
In Vitro bacterial reverse mutation (S. typhimurium/E. coli)
46264304 (2001)

15, 50, 150, 500, or 5000 g/plate (std. plate test) (-/+ activation)

Acceptable (guideline)
Negative.
870.5300
In Vitro mammalian gene mutation (CHO/HGPRT)
46264307 (2002)

0, 25.0, 50.0, 100.0, 156.3, 200.0, 312.5, 400.0, 625.0, 800.0, 1250.0, 2500.0 or 5000.0 u g/mL (- activation)

0, 50.0, 100.0, 156.3, 200.0, 312.5, 400.0, 625.0, 800.0, 1200.0, 1250.0, 2500.0 or 5000.0 ug/mL (+ activation)

Unacceptable (guideline)
Inconclusive without metabolic activation due to compound precipitation at all concentrations tested

Inconclusive with metabolic activation due to compound precipitation at all concentrations tested
870.5375
In Vitro mammalian chromosomal aberration  (V79)
46264309 (2002)

0, 3.125, 6.25, 12.5, 25.0 or 50.0 u g/mL (- activation);

0, 25.0, 50.0 or 100.0 u g/mL (+ activation)

Acceptable (guideline)
Positive without metabolic activation at soluble (12.5 u g/mL) and insoluble (>= 25 u g/mL) concentrations.  

Negative with metabolic activation.
870.5395
In Vivo mammalian cytogenetics  (mouse micronucleus)
46264311 (2002)

0, 500, 1000 or 2000 mg/kg

Acceptable (guideline)
Negative.
870.5550
UDS in mammalian cells
46264313 (2003)

0, 1000 or 2000 mg/kg

Acceptable (guideline)
Negative.
870.6200
Acute neurotoxicity rats (gavage)
46264318 (2003)

0, 125, 500, or 2000 mg/kg/day

Acceptable (guideline)
NOAEL = 2000 mg/kg/day (HDT)  
LOAEL > 2000 mg/kg/day
870.6200
Subchronic neurotoxicity rats (gavage)
46264319 (2003)

0, 12, 36, 150 or 300 mg/kg/day

Acceptable (guideline)
NOAEL = 36 mg/kg/day
LOAEL = 150 mg/kg/day, based on death, reduced general condition, and piloerection (M&F); hyperthermia (M); abnormal squatting posture, hypothermia, decreased BW, BW gain, and food consumption (F)
870.6300
Developmental Neurotoxicity
rats (gavage) (range-finding)
47839302 (2005)

0, 50, 80, or 120 mg/kg bw/day
Maternal NOAEL = 80 mg/kg/day
Maternal LOAEL = 120 mg/kg/day, based on poor general state and total litter loss in both cohorts.

Offspring NOAEL = 80 mg/kg/day
Offspring LOAEL = 120 mg/kg/day based on pup mortality
870.7485
Metabolism rats (gavage)
46264230 (2002)

30 and 1000 mg/kg (single dose)

30 mg/kg (14-day repeated dosing)

Acceptable (guideline)
Following a single oral dose of [benzonitrile ring-U-[14]C] and [trifluoromethoxyphenyl ring-U-[14]C] metaflumizone, the amount of absorption was <7.5% for the 30 mg/kg dose group and <2% for the 1000 mg/kg dose group after 72 hours. The majority (>90%) of the 2 doses were excreted in the feces.  Biliary excretion accounted for <5% of the low dose and <2% of the high dose.  Urinary excretion was also low at 1-2%.  The absorbed doses were distributed quickly to the muscle, liver, kidney, and fat within 0.5-2 hours.  Total radioactivity in muscle, liver, kidney, blood, and plasma reached maximal levels at or near the blood Tmax irrespective of sex or dose.  Near the blood Tmax, radioactivity was highest in fat or liver, followed by kidney and blood/plasma/muscle.  Unchanged parent accounted for the majority of radioactive residue in muscle, liver, kidney, fat and plasma.  BAS 320I was metabolized via hydroxylation of the aniline or benzonitrile ring and hydrolysis of the central hydrazine carboxamide group to yield the aniline derivatives and phenacyl benzoylnitrile derivatives.  The trifluoromethoxyaniline was shown to conjugate with malonic and oxalic acids.  Glycine conjugation occurred at the carboxyl group of the cyanobenzoic acid. Glutathione conjugation occurred by displacement of one of the fluorine atoms of the trifluoromethyl or trifluoromethoxy group to form S-(N-(N-γ-glutamyl))-cysteinyl-, glycyl-conjugate.

After 14 days of daily dosing at 30 mg/kg/day, metaflumizone concentrations were up to 26 (muscle), 13 (liver), 13 (kidney), 43 (fat), and 26 (plasma) times higher than those found after a single oral dose.  [Trifluoromethoxyphenyl ring- U-[14]C]-labeled parent/metabolite(s) appeared to partition into RBCs, rather than plasma, in both sexes after 14 days of dosing.
Single, low-dose absorption study (gavage vs dietary)

47249001 (2007)

0.73 mg/kg bw (single-dose gavage)
0.76 mg/kg bw (single-dose dietary)

Unacceptable/non-guideline 
(biliary excretion not measured)
10.8% absorption via gavage

23.0% absorption via diet

Although measurement of radioactivity excreted into the bile was not made and is necessary for a complete characterization of absorption, study data indicate that the relative percentage of administered dose excreted into bile under either dosing regimen would be similar
870.7800
Immunotoxicity
28 days
(oral gavage)

48448601(2011)
0, 15, 40, or 75 mg/kg/day
Immunotoxicity: NOAEL = 75 mg/kg bw/day
 LOAEL =  not identified
Systemic toxicity: NOAEL = 40 mg/kg bw/day
LOAEL = 75 mg/kg bw/day based on decreases in body weights, body weight gains, and food consumption.
                                   Z-isomer
870.3100
3-month oral
rats - gavage
46264301 (2004)

0, 100, 300 or 1000 mg/kg/day

Acceptable (guideline)
NOAEL = 100 (F) and 300 (M) mg/kg/day  
LOAEL = 300 (F) and 1000 (M) mg/kg/day, based on mortality, clinical signs (reduced general condition and piloerection), and lymphocyte necrosis in the mesenteric lymph node (F) and decreased motor activity (M&F)
870.5100
In Vitro bacterial reverse  mutation (S. typhimurium/E. coli)
46264305 (2002)

20-5000 u g/plate (std. plate test) (-/+ activation)

4-2500 u g/plate (preincubation assay) (-/+ activation)

Acceptable (guideline)
Negative with and without metabolic activation.

Negative with and without metabolic activation.
                              Metabolite M320I23
870.3100
3-month oral rats - gavage
46264242 (2004)

0, 50, 200, or 1000 mg/kg/day

Acceptable (guideline)
NOAEL = 1000 mg/kg/day (HDT)
LOAEL > 1000 mg/kg/day
870.5100
In vitro bacterial reverse  mutation (S. typhimurium, E. coli)
46264306 (2003)

20, 100, 500, 2500, or 5000 ug/plate (std. plate test) (-/+ activation) 

62.5, 125, 250, 500, 1500 ug/plate (preincubation assay) (-/+ activation)

Acceptable (guideline)
Negative with and without metabolic activation.

Negative with and without metabolic activation.
870.5300
In Vitro mammalian gene mutation (CHO/HGPRT)
46264308 (2004)

0, 0.125, 0.25, 0.5, 1.0, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, or 6.0 u g/mL (- activation)

0, 1.25, 2.5, 3.125, 5, 6.25, 10, 12.5, 15, 20, 25, 30, 40, 50, or 100 u g/mL (+ activation) 

Unacceptable (guideline)
Negative without metabolic activation.

Inconclusive with metabolic activation due to compound precipitation at all concentrations tested
870.5375
In Vitro mammalian chromosomal aberration  (V79)
46264310 (2004)

0, 0.25, 0.5 or 1.0 ug/mL (- activation)

0, 1.0, 5.0, 7.5, 10.0 or 12.5 ug/mL  (+ activation)

Acceptable (guideline)
Negative without metabolic activation.

Positive with metabolic activation.
870.5395
In Vivo mammalian cytogenetics  (mouse micronucleus)
46264312 (2004)

0, 500, 1000 or 2000 mg/kg 

Acceptable (guideline)
Negative.
Appendix B.  Chemical Names and Structures

                               Common name/code
                                 Chemical name
                              Chemical structure
Metaflumizone E isomer
4-{(2E)-2-({[4-(trifluoromethoxy)-anilino]carbonyl}hydrazono)-2-[3-(trifluoromethyl)phenyl]ethyl}-benzonitrile

2-[2-(4-cyanophenyl)-1-[3-trifluoromethyl)phenyl]ethylidene]-N-[4-hydrazinecarboxamide (E)
                                       
Metaflumizone Z isomer
2-[2-(4-cyanophenyl)-1-[3-trifluoromethyl)phenyl]ethylidene]-N-[4-hydrazinecarboxamide (Z)
                               \s \* MERGEFORMAT
M320I04
4-{2-oxo-2-[3-(trifluoromethyl)phenyl]ethyl}-benzonitrile
                                       
M320I05
(CL 65504)
p-trifluoromethoxyaniline
                                       
M320I06
(found in tomato and cattle urine)
4-cyanobenzoic acid
                                       
M320I07
2-[2-(4-cyanophenyl)-2-hydroxy-1-[3-trifluoromethyl)phenyl]ethylidene]-N-[4-hydrazinecarboxamide
                                       
M320I10

                                       
M320I13
{[(4_cyanophenyl)acetyl]amino}acetic acid
                                       
M320I17
(isolated and identified in goat urine)
oxo{[4_(trifluoromethoxy)phenyl]amino}acetic acid
                                       
M320I22 (E and Z isomers)
                                      --
                                       
M320I23
4-{5-hydroxy-3-oxo-4-[4-(trifluoromethoxy)phenyl]-6-3-(trifluoromethyl)phenyl]-2,3,4,5-tetrahydro-1,2,4-triazin-5-yl}benzonitrile
                                       
M320I24 (E and Z isomers)
                                      --
                                       
M320I25
4-{2-hydroxy-2-[3-(trifluoromethyl)phenyl]ethyl}-benzonitrile
                                       
M320I26
4-amino-5-{2-(4-cyanophenyl)-1-[3-(trifluoromethyl)phenyl]ethoxy}-5-oxopentanoic acid
                                       
M320I28

(hydrolysis product of Metaflumizone)
N-[4-(trifluoromethoxy)phenyl]-acetamide
                                       

