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

OFFICE OF
PREVENTlON. PESTICIDES
AND TOXIC SUBSTANCES

Date: March 17,2010

MEMORANDUM

SUBJECT:

Herbicide. Aminocyclopyrachlor: Human Health Risk Assessment for Proposed Uses as an

. sk Assessment Review Committee

## 1?.~ 

# 3/(7/=0**~~** S/I7/4nD Health Effects 01 15100 (7509

Ray Kent, Branch Chief

Susan Hummel, Senior**Sci~csJ.1** Richard Loranger and Jack Arth

Health Effects Division (7509P)

Jim Tompkins and Mindy Ondish, PM 25

Herbicide Branch Registration Division (7505P) THROUGH:

TO: PC Codes: 288008,288009,288010, DP Barcode: D369057 611472, 688008

Decision No.: 400967 Registration Nos.: 00352-lNG,00352-lNN,
00352-lNT, 00352-lNU, 00352-IRE, 00352-
IRG,00352-IRL,00352-IRR,00352-IRU, 00352-TIA,00352-TIL, 00352-TIT, 00352-
TIU, 00352-TOA, 00352-TOE, 00352-TOG, 00352-TOI, 00352-TOL, 00352-TOO,
00352-TOT,00352-TOU

Petition No.: N/A Re2Ulatorv Action: Section 3

Risk Assessment Type: Single Chemical Case No.: N/A

TXR No.: N/A CAS No,: 858956-08-8,1:58956-35-1,858954- 83-3,124423-84-3,1759-53-1

MRID Nos.: N/A 40 CFR: NA

# dRi~~~)~ FROM: Jessica Ryman, Ph.D., D.A.B.T., Toxicolo}..ist



### James S 

### Miller, Environrnenta:..?.2;icx::::::.:...

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# .**lJtt/~** Thurston Morton, Chemist ./;) 'v'

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Page I of76Table of Contents
1.0 Executive Summary .......................................................................................................... 4
2.0 Ingredient Profile .............................................................................................................. 9 2.1 Summary of Proposed Uses.................................................................................... 9
2.2 Structure and Nomenclature ................................................................................. 11 2.3 Physical and Chemical Properties......................................................................... 13
3.0 Hazard Characterization and Dose-Response Assessment ......................................... 15
3.1 Hazard Characterization........................................................................................ 15 3.1.1 Database Summary ................................................................................... 15
3.1.1.1 Studies available and consider ed (animal, human, general literature)................................................................................................... 15 3.1.1.2 Mode of action, metabolism, toxicokinetic data........................ 15 3.1.1.3 Sufficiency of studies/data......................................................... 16 3.1.2 Toxicological Effects................................................................................ 16 3.2 Consideration of Toxicity to Children .................................................................. 17 3.2.1 Adequacy of the Toxicity Database.......................................................... 18 3.2.2 Evidence of Neurotoxicity ........................................................................ 18 3.2.3 Evidence of Developmental Toxicity ...................................................... 18 3.2.4 Evidence of Reproductive Toxicity .......................................................... 18 3.2.5 Determination of Susceptibility ................................................................ 18 3.2.6 Recommendation for a Developm enal Neurotoxicity Study.................... 19 3.3 Dose-Response Assessment.................................................................................. 19 3.3.1 Acute Reference Dose (aRfD) - All Populations...................................... 19 (Includes Females 13-49) 3.3.2 Chronic Reference Dose (cRfD)............................................................... 19 3.3.3 Incidental Oral Exposure (Shor t- and Intermediate-Term)....................... 19 3.3.4 Dermal Absorption.................................................................................... 20 3.3.5 Dermal Exposure (Short-, Intermediate- and Long-Term)....................... 20 3.3.6 Inhalation Exposure (Short-, Intermediate- and Long-Term)................... 20 3.3.7 Level of Concern for Margin of Exposure................................................ 21 3.3.8 Recommendation for Aggregate Exposure Risk Assessments ................. 21 3.3.9 Consideration of Carcinogenic Potential ................................................ 21 3.3.10 Summary of Toxicological Doses an d Endpoints for Use in Human Risk

Assessments .......................................................................................................... 22
4.0 Public Health and Pesticide Epidemiology Data .......................................................... 24
5.0 Dietary Exposure/Risk Characterization ..................................................................... 25 5.1 Environmental Degradation.................................................................................. 25 5.1.1 Stability, mobility, and degradates............................................................ 25 5.1.2 Toxicity profile of major degradates......................................................... 25 5.1.3 Degradates of concern............................................................................... 26 5.1.4 Drinking Water Residue Profile................................................................ 27 5.2 Dietary Exposure and Risk ................................................................................... 29 5.2.1 Acute Dietary Exposure/Risk ................................................................... 30 5.2.2 Chronic Dietary Exposure/Risk ................................................................ 30 5.2.3 Cancer Dietary Risk.................................................................................. 32
6.0 Residential (Non-Occupational) Exposure/Risk Characterization ............................ 32

Page 2 of 766.1 Residential Handler Exposure............................................................................... 33 6.1.1 Data and Assumptions for Residential Handler Exposure Scenarios ....... 33 6.1.1.1 Unit Expsoures........................................................................... 33
6.1.1.2 Area Treated............................................................................... 33 6.1.1.3 Application Rate ........................................................................ 33
6.1.1.4 Results and Conclusions ............................................................ 34 6.2 Residential Postapplication Exposure................................................................... 34 6.2.1 Data and Assumptions for Resident ial Postapplication Scenarios ........... 35
6.2.2 Results and Conclusions ........................................................................... 35 6.3 Spray Drift ........................................................................................................... 35 7.0 Aggregate Risk Assessment s and Risk Characterization ............................................ 36
8.0 Occupational Exposure/Risk Pathway .......................................................................... 36
8.1 Short-Term and Intermediate-Term Handler Risk................................................ 36 8.1.1 Data and Asuumptions for Occupati onal Handler Exposure Scenarios ............... 37 8.1.1.1 Unit Expsoures........................................................................... 37
8.1.1.2 Area Treated............................................................................... 38 8.1.1.3 Application Rate ........................................................................ 38
8.1.1.4 Results and Conclusions ............................................................ 39 8.2 Short-Term and Intermediate-Term Postapplication Risk.................................... 41
9.0 Data Needs and Label Recommendations .................................................................... 41 9.1 Toxicology ............................................................................................................ 41 9.2 Occupational and Resi dential Expsoure ............................................................... 41
10.0 References (Memoranda) ............................................................................................... 42 Appendix A: Toxicology Assessment ........................................................................... 43 A.1 Toxicology Data Requirements ............................................................................ 43 A.2 Toxicity Profiles.................................................................................................... 44
A.3 Executive Summaries............................................................................................ 48 A.3.1 Subchronic Toxicity................................................................................. 48 A.3.2 Prenatal Developmental Toxicity............................................................. 53 A.3.3 Reproductive Toxicity.............................................................................. 55 A.3.4 Chronic Toxicity ...................................................................................... 56 A.3.5 Carcinogenicity ........................................................................................ 57 A.3.6 Mutagenicity ............................................................................................ 57 A.3.7 Neurotoxicity ........................................................................................... 60
A.3.8 Metabolism............................................................................................... 63 A.3.9 Special/Other Studies............................................................................... 66 A.4 References (In MRID Order) ............................................................................... 69 Appendix B: Review of Human Research ................................................................... 75 Appendix C: Chemical Structures of Degradates ...................................................... 75

Page 3 of 761.0 Executive Summary

This document describes the human health risk assessment conducted to support the Section 3 registration decision of a new herbicide active ingr edient, aminocyclopyrachlor.

Aminocyclopyrachlor is a member of the pyrimid ine carboxylic acid ch emical class. The pesticidal mode of action is dysregulation of ge ne products involved in a uxin receptor activity,
which interferes with normal shoot and root development to stop the growth of weeds. Aminocyclopyrachlor is being registered for uses of general weed and br ush control on private, public and military lands including sod farms, un-cultivated non-agricultural areas such as airports, highways, railroads, golf courses, lumber yards, wild life habitats, multi family residential complexes, recreation areas, utility rights of way, w ith residential use specified for
lawn/turf.

Three forms of aminocyclopyrachlor are being registered: the pare nt acid (PC Code 288008), the potassium salt (PC Code 288010), and the me thyl ester (aminocyclopyrachlor-methyl, PC Code 288009). All three forms are components of both manufacturing and end-use products. The parent acid (aminocyclopyrachlor) is considered the active ingredient.

Hazard and Dose-Response Considerations

The toxicology database for am inocyclopyrachlor is adequate for risk assessment for the proposed use patterns. Acute t oxicity studies investigated both aminocyclopyrachlor and aminocyclopyrachlor-methyl, since both will be market ed in end-use products. Both exhibit low acute toxicity by oral, dermal, or inhalation routes of exposure, and neither cause skin
sensitization or irritation. Howeve r, both caused mild eye irritation.

Pharmacokinetic studies via th e oral route showed that both aminocyclopyrachlor and aminocyclopyrachlor-methyl are rapidly absorb ed, with rapid metabolic conversion of aminocyclopyrachlor-methyl to ami nocyclopyrachlor. Elimination is almost complete within 24 hours. Subchronic dietary, reproduc tive toxicity, and gene mutati on studies were performed with both aminocyclopyrachlor and aminocyclopyrachlor-m ethyl at similar doses. These studies all yielded similar results. These re sults, together with similar acu te toxicity profiles and evidence from metabolism studies showing that aminoc yclopyrachlor-methyl is rapidly converted to aminocyclopyrachlor, form a scie ntific justification for consid ering aminocyclopyrachlor and aminocyclopyrachlor methyl toxi cologically equivalent, thus allowing bridging the toxicity database for aminocyclopyrachlor-methyl wi th studies using aminocyclopyrachlor.

Aminocyclopyrachlor and aminocycl opyrachlor-methyl have low subchronic toxicity via the oral route. The most sensitive species is the rat, with decreased body weight at the limit dose in subchronic dietary studies as the most sensitive e ndpoint of toxicity. The major effect observed across species for aminocyclopyrach lor was decreased body weight at the limit dose. No toxicity
was observed in subchronic diet ary studies in dogs at the hi ghest dose of aminocyclopyrachlor tested, which was half the limit dose. No targ et organ of toxicity was identified. No sex differences in toxicity were observed for eith er aminocyclopyrachlor or aminocyclopyrachlormethyl.

Page 4 of 76Aminocyclopyrachlor was not neurotoxic when admi nistered acutely or subchronically via the oral route. Aminocyclopyrachlor-methyl showed no evidence of neurotoxicity or reproductive toxicity in an extended one ge neration reproductive toxicity st udy in rats. Aminocyclopyrachlor did not cause developmental toxic ity in rats and rabbits. Theref ore, there is low concern for reproductive, developmental, or neur otoxicity for aminocyclopyrachlor and aminocyclopyrachlor-methyl.

Aminocyclopyrachlor and aminocycl opyrachlor-methyl are considered to have low potential to cause chronic toxicity or carci nogenicity. No evidence of genotoxic effects were observed in mutagenicity studies in vitro for aminocyclopyrachlor and aminocyclopyrachlor-methyl or in

vivo for aminocyclopyrachlor. No evidence of ta rget organ toxicity was observed in oral subchronic studies for aminocyclopyrachlor and aminocyclopyrachlor-methyl at doses exceeding
the limit dose.

Immunotoxicity was investigated via the oral route in two species (rats and mice) for aminocyclopyrachlor. There was no evidence of immunotoxicity.

Exposures to aminocyclopyrachlor and aminocycl opyrachlor-methyl will occur primarily by the dermal route and by inhalation durin g occupational and residential use. Acute toxicity via the dermal route for aminocyclopyrachlor or aminocyclopyrachlor-methyl was low (Category IV). No dermal toxicity endpoint was identified for aminocyclopyrachlor because no toxicity was observed at the limit dose in a 28 day dermal toxicity study. The dermal toxicity of aminocyclopyrachlor-methyl is expected to be si milar to aminocyclopyrachlor, based on similar acute dermal, acute oral, and subchronic oral toxi city profiles. Acute st udies also indicated low toxicity of aminocyclopyrachlor and aminocyc lopyrachlor-methyl via inhalation, since acute inhalation toxicity with aminoc yclopyrachlor was low (Category IV ). No subchronic inhalation studies were available for aminocyclopyrachlo r or aminocyclopyrachl or-methyl. However, subchronic toxicity is of low c oncern due to low acute toxicity and high margins of exposure.

An environmental photodegradate of aminocyclopyr achlor present on ly in surface water is of concern for drinking water exposures. This photodegradate, IN-V0977 (cyclopropane carboxylic acid), has a different mode of toxic action than aminocyclopyrach lor. Oral administration of cyclopropane carboxylic aci d causes severe impairment of mitochondrial function by inhibiting the beta oxidation of fatty acids, resulting in micr ovesicular steatosis (accumulation of small fat droplets in cells). The liver is the most se nsitive organ, and hepato cellular microvesicular steatosis is often accompanied by liver necrosis and inflammation, decreased hepatic glycogen, and decreased blood glucose levels. These effects have been obser ved with acute (one to three days) and longer (up to 14 days) exposure. The mo st sensitive species is the rabbit. Hepatic
microvesicular steatosis in th e rabbit follows a different dose-response than body weight
decreases observed with aminoc yclopyrachlor and aminocyclopyrach lor-methyl in rats, with a
LOAEL that is 100-fold lower.

Dietary Exposure Considerations

There are no proposed food uses for aminocyc lopyrachlor, however, dietary exposure to aminocyclopyrachlor and its environmental degradates from drinking water were considered. .

Page 5 of 76Page 6 of 76 Since aminocyclopyrachlor-methyl rapidly hyd rolyses to aminocyclopyrachlor in the environment, there are no risks of concern for drinking water exposures to aminocyclopyrachlormethyl. Aminocyclopyrachlor is persistent in both aerobic and an aerobic aquatic environments.
Consideration of acute and chroni c dietary endpoints is relevant for the proposed use patterns. No endpoint for acute toxicity was identified fo r aminocyclopyrachlor, a nd so no acute dietary risk assessment was performed. Risks for chr onic dietary exposures to aminocyclopyrachlor from drinking water were considered, and the risk estimates for the general U.S. population and all other regulated population subgro ups are below the leve l of concern. Cancer risks for dietary exposure to aminocyclopyrachlor in drinking water were not assessed.

The major route of environmental degradation of aminocyclopyrachlor is aqueous photolysis, which produces five degradates. Of thes e, one environmental degradate, IN-V0977 (cyclopropane carboxylic acid), was of concern. Dietary assessments of acute and chronic dietary exposures of cyclopropane carboxylic acid from drinking water were performed, and
were below the level of concern. Cancer risks for dietary exposure to cyclopropane carboxylic acid in drinking water were not assessed.

Residential Exposure Considerations

Residential handler exposures to aminocycl opyrachlor and aminocyclopyrachlor-methyl may occur dermally and by inhalation. The durations of exposures relevant to the proposed use patterns are short-term and intermediate term. No dermal hazard for aminocyclopyrachlor and aminocyclopyrachlor-methyl was identified because no toxicity was observed at the limit dose in a subchronic dermal exposure study with aminocyc lopyrachlor. Therefore, a quantitative dermal
risk assessment was not done. Inhalation risk was assessed by analysis of short-term and intermediate-term exposures using the product wi th the highest application rate and hazards
identified in subchronic oral toxi city studies. No risks of conc ern for residential handlers were identified in residential exposure scenarios.

Residential exposures to aminocyclopyrachlor an d aminocyclopyrachlor-methyl can also occur after application (post-applica tion exposures) by different expos ure routes for a variety of populations. Young children are a population of particular concern, and post-application exposures via the oral route (hand-to-mouth, object -to-mouth, and ingestion of soil) were also considered for the product with the highest appl ication rate. No single or combined risks of concern for post-application exposures of con cern were identified in any population, including
children.

Aggregate Exposure Considerations

The potential for significant aggregate risk s from exposures to aminocyclopyrachlor was
considered. There are no food uses for am inocyclopyrachlor, and dietary exposure to aminocyclopyrachlor from drinking wa ter is expected to be low. The margins of exposure from residential uses are very high. Thus, there is low potential fo r significant aggregate exposures and resulting risks from aminocyclopyrachlo r from drinking water and from residential applications.Occupational Exposure Considerations

Occupational handler exposures to aminocyclopyrachlor and aminocyclopyrachlor-methyl may occur dermally and by inhalation and are short-term or intermed iate-term for the proposed use pattern. No dermal hazard for aminocycl opyrachlor and aminocyclopyrachlor-methyl was identified because no toxicity was observed at the limit dose in a subchronic dermal exposure study with aminocyclopyrachlor. Therefore, a quan titative dermal risk assessment was not done. Inhalation risk was assessed by analysis of shor t-term and intermediate-term exposures using the product with the highest applica tion rate and hazards identified in subchronic oral toxicity
studies. No risks of concern fo r occupational handlers were id entified in occupational exposure
scenarios.

Occupational post-application e xposures via the dermal route were not assessed because no toxicity was observed at the limit dose in a subchronic dermal toxicity study with aminocyclopyrachlor. Occupati onal post-application exposures to aminocyclopyrachlor and aminocyclopyrachlor-methyl via the inhalation r oute were not assessed because no risks of concern were identified in application scenario s, which would have higher exposures than postapplication due to low vapor pressu re and dilution in outdoor air.

Environmental Justice Considerations

Environmental justice concerns, to the extent possible, were consid ered in this human heath risk assessment in accordance with U.D. Executive Order 12989, “Federal Actions to Address Environmental Justice in Minority Popul ations and Low-Income Populations” ( http://www.epa/gov/compliance/resources/policies/ej/exec_order_12898.pdf ).

As part of every pesticide risk assessment, OP P 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 ar ound the home that involve pesticide use in a residential setting. Whenever ap propriate, non-dietary exposures ba sed 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-appli cation are evaluated. Further c onsiderations 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 pattern s among specific subgroups.

Use of Humans in Research

This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pesticide or other chemical. These studies (listed in Appendix B) have been determined to require a re view of their ethical conduct, a nd have received that review, and were determined to be appropr iate (ethically conducted) for purposes of risk assessment.

Page 7 of 76Additional Data Needs and Recommendations

No additional data are required to assess the human health risks of aminocyclopyrachlor or aminocyclopyrachlor-methyl for the use patterns described in this risk assessment. Additional
data are needed to address the hazard of ch ronic exposure to the environmental degradate cyclopropane carboxylic acid. HED recommends th at registration of the aminocyclopyrachlor and aminocyclopyrachlor-methyl products describe d in this risk assessm ent be conditional until the hazards of chronic exposure to cyclopropane carboxylic acid are identified in a repeated dose study in a sensitive species.

Label directions call for a restrict ed entry interval (REI) of 4 hour s, however due to a category III in acute eye irritation HED maintains that a RE I of 12 hours is appropria te and that all label directions reflect this change . Also, labels for 352-TOA, 352-TIU, and 352-TOL do not state application rates and so should be revised.

Page 8 of 762.0 Ingredient Profile

2.1 Summary of Proposed Uses

Aminocyclopyrachlor (acid and potassium salt) and aminocyclopyrachlor-methyl are being registered for uses of general weed and brus h control on private, public and military lands including sod farms, un-cultivated non-agricultural areas such as airports, highways, railroads, golf courses, lumber yards, wild life habitats, multi family residential complexes, recreation areas, utility rights of way, with residential use sp ecified for lawn/turf. Products will be applied in three different formulations: granular, water di spersible granular (i.e. dry flowable), and as a soluble liquid. Occupational appl ication scenarios include: aeri al (fixed wing or helicopter), ground boom, right of way sprayer, push type sp reader, push cyclone spreader, tractor drawn broadcast spreader, and LOC handgun equipment (which are typically used by a lawn care operator or landscape maintenance personnel). Broadcast applications may be performed by using either a single ground boom, a tractor type broadcast, or as a banded application for preplant, pre-emergence, or early post-emergence. Pre-plant applications ca n be made as either a single or split application that is either surface applied or incor porated. Residential application scenarios include low pressure handwand, hose-end sprayer, and hand held spreader (i.e. belly grinder).

A summary of the proposed us e profile is presented in Table 2.1.1. For products containing aminocyclopyrachlor-methyl, maximum application units are in pounds of acid equivalent per

acre.

Table 2.1.1. Summary of Directions for Use of Aminocyclopyrachlor (Parent Acid and Potassium Salt) and Aminocyclopyrachlor-Methyl Application Equipment 1 Sites EPA Reg. # Max Application 2 Formulation

Non-Crop 352-TIA

352-TIT

352-TIL 0.28

Turf/Sod Farm 352-TOE

352-TOU

352-TOE

352-TOU Water Dispersible

Granular

Turf/Lawn Golf

Course 352-TOG Groundboom (Open Cab)

Turf/Sod Farm. 352-TOG 0.07

Soluble Liquid

1 No chemical-specific handler exposure da ta were submitted in support of this registration; therefore data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 were used.

2 The maximum application rate (lb ae/Acre) = pounds of acid equivalent per acre.

Page 9 of 76Table 2.1.1. Summary of Directions for Use of Aminocyclopyrachlor (Parent Acid and Potassium Salt) and Aminocyclo pyrachlor-Methyl (Continued)

Application Equipment 1 Sites EPA Reg. # Max Application 2 Formulation

Non-Crop 352-TIA

352-TIT

352-TIL 0.28 Water Dispersible

Granular LCO Handgun

Turf/Lawn/Sod
Farm/Golf Course 352-TOG

352-TOE

352-TOU 0.07 Soluble Liquid

Aerial (Fixed Wing)
Enclosed Cockpit Non-Crop 352-TIA

352-TIT

352-TIL 0.28 Water Dispersible

Granular

Push Cyclone Spreader

Push Type

Spreader

Tractor Drawn
Broadcast Spreader Sod Farm Golf

Course 352-IRU

352-IRE

352-IRG

352-TOT 0.108 Granular

Non-Crop 352-TIA

352-TIT

352-TIL 0.28 Water Dispersible

Granular

Right of Way Sprayer Turf/Lawn
Sod Farm
Golf Course 352-TOG

352-TOE

352-TOU 0.07 Soluble Liquid

1 No chemical-specific handler exposure da ta were submitted in support of this registration; therefore data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 were used.

2 The maximum application rate (lb ae/Acre) = pounds of acid equivalent per acre.

Page 10 of 76Table 2.1.1. Summary of Directions for Use of Aminocyclopyrachlor (Parent Acid and Potassium Salt) and Aminocyclo pyrachlor-Methyl (Continued)

Application Equipment Sites EPA Reg. # Max Application 1 Formulation

Low Pressure

Handwand Soluble Liquid

Hose-End Sprayer ("Mix Your Own" 0.07

Water dispersible

granular

Belly Grinder Turf (Lawns) 352-TOG

352-TOE

352-TOU

352-TOT

352-IRG

352-TOI

352-IRU

352-TOO

352-IRL

352-INN

352-ING

352-INU

352-INT

352-IRR 0.108 Granular (dry bulk fertilizer)

1 No chemical-specific handler exposure da ta were submitted in support of this registration; therefore data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 were used.

2 The maximum application rate (lb ae/Acre) = pounds of acid equivalent per acre.

2.2 Structure and Nomenclature

Three forms of aminocyclopyrachlor are being registered: the pare nt acid (PC Code 288008), the potassium salt (PC Code 288010), and the me thyl ester (aminocyclopyrachlor-methyl, PC Code 288009). All three forms are components of both manufacturing and end-use products.

Page 11 of 76Table 2.2.1. Test Compound Nomenclature-Aminocyclopyrachlor (parent acid)

Chemical Structure N

N

NH 2 Cl O

OH

Empirical Formula C 8 H 8 ClN 3 O 2 Molecular Weight 213.6 g/mole

Common Name Aminocyclopyrachlor Company Experimental

Name DPX-MAT28

IUPAC Name 6-amino-5-chloro-2-cyc lopropyl-4-pyrimidinecarboxylic acid

CAS Name 6-amino-5-chloro-2-cyclopropyl-4-pyrimidinecarboxylic acid CAS Registry Number 858956-08-8

Chemical Class Pyrimidine carboxylic acid Impurities of Concern None

Table 2.2.2. Test Compound Nomenclature-Am inocyclopyrachlor (potassium salt)

Chemical Structure N

N

NH 2 Cl O

O – K +

Empirical Formula C 8 H 7 ClKN 3 O 2 Common Name Aminocyclopyrachlor Company Experimental

Name DPX-MAT28

IUPAC Name potassium 6-amino-5-chloro -2-cyclopropylpyrimidine-4- carboxylate

CAS Name potassium 6-amino-5-ch loro-2-cyclopropyl-4- pyrimidinecarboxylate CAS Registry Number 858956-35-1

Chemical Class Pyrimidine carboxylic acid Impurities of Concern None

Page 12 of 76Table 2.2.3. Test Compound Nomenclature-Aminocyclopyrachlor-methyl (methyl ester)

Chemical Structure N

N

NH 2 Cl O

O

CH 3

Empirical Formula C 9 H 10 ClN 3 O 2 Molecular Weight 227.6 g/mole

Common Name Aminocyclopyrachlor-methyl Company experimental

Name DPX-KJM44

IUPAC Name methyl 6-amino-5-chloro-2 -cyclopropylpyrimidine-4- carboxylate

CAS Name methyl 6-amino-5-chlo ro-2-cyclopropyl-4- pyrimidinecarboxylate CAS Registry Number 858954-83-3

Chemical Class Pyrimidine carboxylic acid Impurities of Concern None

2.3 Physical and Chemical Properties

The physical and chemical property data for aminocyclopyrachlor technical (DPX-MAT 28 Technical Herbicide 352-TIE) were summari zed in a Memorandum from A. Abramovitch (D357886, August 16, 2009). These data are summarized in Table 2.3.1.

The physical and chemical property data for aminocyclopyrachlor-methyl technical (DPXKJM44 Technical Herbicide 352-TIG) were al so summarized in a Memorandum from A. Abramovitch (D357975, August 25, 2009). These data are summarized in Table 2.3.2.

Page 13 of 76Table 2.3.1. Physiochemical Properties of Aminocyclopyrachlor

Parameter Value Reference Melting point 140.8oC 47559809 pH (20.1°C) 3.34 47559812 Density (20°C) 1.34 g/mL 47559809

Water solubility (20°C) 3.13 g/L (pH 4) 4.20 g/L (pH 7) 3.87 g/L (pH 9) 47559816

Vapor pressure 6.92 x10 -6 Pa (20°C)

4.91 x10 -6 Pa (25°C) 47559818

Dissociation constant (20°C) 4.65 47559814

Octanol/water partition coefficient (log 10 ) at 20°C -1.01 (pH 4) -2.48 (pH 7) 1.07 (mili-Q water) 47559815

UV/visible absorption spectrum pH/nm
1.8/220 7.0/285, 240, 210 10.5/280, 240, 210 47573401

Table 2.3.2. Physiochemical Properties of Aminocyclopyrachlor-methyl

Parameter Value Reference Melting point 148.9oC 47559829 pH (20.1°C) 6.16 47559832

Density (20°C) 1.44 g/mL 47559828

47559829 Water solubility (20°C) 0.354 g/L 47559835

Vapor pressure 4.19 x10 -4 Pa (20°C)

4.45 x10 -4 Pa (25°C) 47559902

Dissociation constant (20°C) Not applicable Not applicable Octanol/water partition coefficient (log 10 ) at 20°C 1.87 47559834

UV/visible absorption spectrum pH/nm 1.8/300, 220 7.0/300, 235, 205

10.5/285, 235 47559833

Page 14 of 763.0 Hazard Characterization and Dose-Response Assessment

3.1 Hazard Characterization

3.1.1 Database Summary

3.1.1.1 Studies available and considered (a nimal, human, general literature)

The following studies were submitted to the Agency for endpoint selection:

• Acute toxicity (OPPTS guideline) acute oral , dermal, inhalation, eye irritation, dermal irritation, and dermal sensitization st udies for aminocyclopyrachlor and aminocyclopyrachlor-methyl and an acute neur otoxicity study for aminocyclopyrachlor.

• Subchronic (OPPTS guideline) toxicity stud ies in rats, mice, and dogs; prenatal development studies in rats and rabbits; a re production and fertility effects study in rats;
acute and subchronic neurotoxic ity studies in rats; a complete mutagenicity battery; immunotoxicity studies in mice and rats ; and a metabolism study in rats for aminocyclopyrachlor. There are also subchroni c oral toxicity and metabolism studies in rats and an in vitro genotoxicity (gene muta tion) study for aminocyc lopyrachlor-methyl.

• One (OECD guideline) extended one generation reproduction study in rats that includes a modified functional observational battery for aminocyclopyrachlor-methyl.

3.1.1.2 Mode of action, metabolism, toxicokinetic data

Aminocyclopyrachlor is a pyrimidine carboxylic acid a nd an auxin-type herbicide. Like other auxin-type herbicides, the pesticid al mode of action in plants is disorganized plant growth. No toxic mode of action for aminocyclopyrachlor or aminocyclopyrachlor-methyl has been
identified in mammals.

Pharmacokinetic studies in rats show that both aminocyclopyrachlor and aminocyclopyrachlor-methyl are rapidly absorbed, with peak concentrations occurring in plasma and red blood cells (RBCs) at 0.3-1.0 hours for aminocyclopyrachlor and at 0.3-0.6 hours after dosing for aminocyclopyrachlor-methyl. Aminocyc lopyrachlor-methyl was ra pidly metabolized to aminocyclopyrachlor (within 30 minutes). No ot her metabolites were identified for either compound. The areas under the cu rve (AUCs) for both compounds s caled with dose, indicating that metabolic processes were not saturated. The (plasma) elimination half-life of aminocyclopyrachlor of 5.6-5.7 hours was shorter than that for aminocycl opyrachlor-methyl at 8.7-13.3 hours. The majority of the administered dose of both compounds was excreted within 24 h, although elimination differed slightl y. For aminocyclopyrachlor, 35.8-53.71% was
eliminated in the urine and 31.4-48.0% was elimin ated in the feces. For aminocyclopyrachlormethyl, the majority was recovered in the urine 78.80-78.82%, with a smaller amount eliminated in the feces (1.72-4.57%). Neither aminocyc lopyrachlor or aminocyclopyrachlor-methyl was eliminated as expired air. No sex differen ces in absorption, distribution, metabolism, or excretion were observed for either aminocyc lopyrachlor or aminocyclopyrachlor-methyl.

Page 15 of 763.1.1.3 Sufficiency of Studies/Data

No additional information was found when screening the general scientific literature for
information relevant to the hazard assessment of aminocyclopyrachlor. However, these studies for aminocyclopyrachlor and aminocyclopyr achlor-methyl in the OPP toxicity database are adequate for risk assessment based on the proposed use pattern.

3.1.2 Toxicological Effects

Acute toxicity studies investigated both aminocyclopyrachlor and aminocyclopyrachlor-methyl, since both will be marketed in end-use products. Both exhibit low acute toxicity by oral, dermal, or inhalation exposure, and neither cause skin sensitization or irritation. However, both cause mild eye irritation. Subchronic dietary, reproducti ve toxicity, and gene mutation studies were also performed with both aminocyclopyrachlor and aminocyclopyrachlor-methyl at similar doses. These studies all yielded similar results. These results, together with evidence from metabolism studies showing that aminocycl opyrachlor-methyl is rapidly converted to aminocyclopyrachlor, form a scie ntific justification for bridgi ng the toxicity database for aminocyclopyrachlor-methyl with studi es using aminocyclopyrachlor.

. Toxic effects of aminocyclopyrachlor and ami nocyclopyrachlor-methyl vi a the oral route of exposure (in the diet) in subchr onic (90-Day) rodent studies we re limited to decreases in body weights ( ≤ 10%), body weight gains, food consumption, and food efficiency in both sexes when these compounds were administered to rats at the limit dose (1000 mg/kg/day). These results were consistent with acute studies, which showed low toxicity vi a the oral route for aminocyclopyrachlor and aminocyclopyrachlor- methyl at the maximum dose (LD50 >5000 mg/kg). Subchronic dietary exposure of dogs to aminocyclopyrachlor resulted in no adverse effects at doses up to almost half the limit dose (426/388 mg/kg/da y in males/females) in both sexes (the limit dose was not tested). No evidence of neurotoxicity in rats was observed after acute (gavage) or subchronic (d ietary) oral administration of aminocyclopyrachlor at the limit dose (2000 mg/kg for acute neur otoxicity, 1000 mg/kg for subchr onic neurotoxicity). An extended one generation reproductiv e toxicity study in rats for aminocyclopyrachlor-methyl that
included a functional obse rvational battery also showed no evidence of ne urotoxicity at the limit dose (1000 mg/kg/day). Aminocyclopyrachlor s howed no evidence of immunotoxicity with dietary exposure at the limit dose (1000 mg/kg) in mice or rats.

There were no adverse effects of aminocyclopyr achlor on prenatal development or maternal health in rats after oral (gav age) administration to dams at the limit dose (1000 mg/kg/day). Administration of aminocyclopyrachlo r to rabbit dams via oral (gav age) at the limit dose resulted
in one treatment-related death and two abortions that were considered secondary to maternal weight losses of 17-19%. No developmental eff ects were observed in rabbit kits. There were no effects of aminocyclopyrachlor on reproduction and fert ility in rats at the lim it dose. Toxicity in parental rats and offspring was limited to d ecreases in body weights at the limit dose. An extended one generation reproductiv e toxicity study in rats for aminocyclopyrachlor-methyl also showed no adverse effects on reproduction at the limit dose.

There was no evidence of toxicity when aminoc yclopyrachlor was administered via the dermal

Page 16 of 76Page 17 of 76 route in rats at the limit dose for 28 days. These results were consistent with acute studies, which
showed no irritation or skin sensitization fo r aminocyclopyrachlor oraminocyclopyrachlormethyl. No subchronic dermal toxicity studies were available for aminocyclopyrachlor-methyl. However, subchronic dermal toxic ity for aminocyclopyrachlor-methyl is expected to be similar to aminocyclopyrachlor, based on similar toxic ity profiles in acute dermal, acute oral, and subchronic oral toxicity profile s. Subchronic inhalation stud ies for aminocyclopyrachlor and aminocyclopyrachlor-methyl were not available. However, the likelihood of subchronic toxicity by the inhalation route is expected to be low, based on acute inhalation studies showing that aminocyclopyrachlor and aminoc yclopyrachlor-methyl had low toxicity at twice the limit concentration of 2 mg/L.

Aminocyclopyrachlor and aminocycl opyrachlor-methyl are considered to have low potential to cause chronic toxicity or carcinogenicity. A battery of mutagenicity studies for aminocyclopyrachlor showed no muta genicity in bacteria, or ma mmalian cells with or without metabolic activation. Aminocyclopyrachlor did not induce chromosomal aberrations in human peripheral blood lymphocytes in vitro in the presence of absence of metabolic activation. Aminocyclopyrachlor did not increase the fre quency of micronucleated polychromactic erythrocytes in bone marrow. Together, these st udies indicate that aminocyclopyrachlor is not genotoxic. Aminocyclopyrachlor-methyl also sh owed no evidence of mutagenicity in an in vitro gene mutation study. No evidence of target or gan toxicity was observed in oral subchronic studies for aminocyclopyrachlor and aminocycl opyrachlor-methyl at doses exceeding the limit
dose.

The toxicity of the environm ental photodegradate of ami nocyclopyrachlor, cyclopropane carboxylic acid, was also assessed because structur al alerts for toxicity for this compound were identified by structural activity relationships (SAR). The most sensitive species, the most sensitive endpoint, and the mechanism of toxicity of cyclopropane carboxylic acid are known. Administration of cyclopropane ca rboxylic acid orally and by in traperitoneal injection (i.p.) acutely (one to three days) or l onger (up to 14 days) re sults in hypoglycemia a nd liver toxicity in rabbits and rats characterized by microvesicular steatosis. The most sensitive species is the rabbit. Hepatic microvesicular steatosis is th e most sensitive endpoint. The mechanism of toxicity is inhibition of beta oxidation of fatty acids in the mitochondria.

3.2. Consideration of Toxicity to Children

Food Quality Protection Act (FQPA) considerations do not apply to aminocyclopyrachlor for the (non-food) use patterns described in this risk assessment. However, the HED risk assessment team has reviewed the toxicity database for indi cations that young may be particularly sensitive to the effects of aminocyclopyrachl or, since some products may be us ed in residential settings.3.2.1 Adequacy of the Toxicity Database

Sufficient data in the form of acceptable O PPTS guideline and non-gui deline studies are
available to evaluate risks to children and are listed below:

• One rat developmental toxicity study w ith aminocyclopyrachlor (guideline)

• One rabbit developmental toxicity study with aminocyclopyrachlor (guideline)

• One two-generation reproduction study in rats with aminocyclopyrachlor (guideline)

• One extended one generation reproduction study in rats with aminocyclopyrachlormethyl (OECD 415) that includes a modifi ed functional observational battery (nonguideline)

3.2.2 Evidence of Neurotoxicity

Sufficient data in the form of acceptable O PPTS guideline and non-gui deline studies are available to evaluate neurotoxicity. No evidence of neurotoxicity was ob served in an acute or subchronic neurotoxicity st udies in rodents at the limit dose after exposure to aminocyclopyrachlor. Also, no evidence of neur otoxicity was observed in an extended onegeneration reproduction study in rats with aminoc yclopyrachlor-methyl that included a modified functional observational battery.

3.2.3 Evidence of Developmental Toxicity

No evidence of developmental toxicity was observed when aminocyclopyrachlor was administered in the diet of rats or orally by gavage to rabbits at the limit dose.

3.2.4 Evidence of Reproductive Toxicity

No evidence of adverse effects of aminocyc lopyrachlor or aminoc yclopyrachlor-methyl on reproduction or fertility parameters were observed in dietary studies with rats.

3.2.5 Determination of Susceptibility

There was no evidence of prenatal toxicity resu lting from exposure to aminocyclopyrachlor. There is no evidence of increased susceptibility following in utero exposure to aminocyclopyrachlor in rats or rabbits in deve lopmental toxicity studies, which showed no adverse effects in offspring at the limit dose. An increase in abortions in maternal rabbits was observed at the limit dose, but this was considered secondary to decreases in body weight. There was also no evidence of increased susceptibil ity of offspring to aminocyclopyrachlor in reproduction and fertility studies in rats, for wh ich adverse effects were limited to decreased body weights in both maternal animals and offspri ng at the limit dose. Therefore, the young are

not considered more susceptible th an adults to adverse effects from aminocyclopyrachlor or aminocyclopyrachlor-methyl.

Page 18 of 763.2.6 Recommendation for a Developmental Neurotoxicity Study

There was no evidence of acute or subchronic neur otoxicity in OPPTS guideline studies in adult animals and no evidence of increased suscepti bility of offspring. Also, no evidence of neurotoxicity was found in mature offspring that were exposed to aminocyclopyrahclor-methyl

in utero in an OECD 415 one generation reprodu ction study, which included a functional observational battery. Therefore, a Developmental Neurotoxicity Study is not required at this time for the use patterns described herein.

3.3 Dose-Response Assessment

3.3.1 Acute Reference Dose (aRfD) – All Populations

No acute endpoint was identified because no toxicity was observed at the limit dose in acute oral studies. This is also applicable to Females 13-49.

3.3.2 Chronic Reference Dose (cRfD)

Study selected: 90-day oral toxicity feeding study in rats (OPPTS 870.3100).

MRID Nos. : 47573403 (2008) and 47560007 (2008) Executive Summary: See Appendix A Dose and Endpoint for Risk Assessment: The NOAEL is the point of departure at 349.4/448.0 mg/kg/day M/F (350 mg/kg/da y). The LOAEL is 1044.6/1424.9 mg/kg/day M/F (limit dose) based on decreased body weights, body weight gains, food consum ption, and food efficiency in
both sexes. Uncertainty Factor(s): 1000X [10X interspecies x 10X intraspecies x 10 X subchronic to chronic]

Comments about selected study: This study is suitable because it is route-specific, of relevant duration, addresses all endpoi nts of concern, and is performed in the most sensitive species at the most sensitive endpoints. Also, the results of th is study with aminocyclopyr achlor are consistent with those of a similar 870.3100 Guideline study with aminocyclopyrachlor-methyl (MRIDs 47560008 and 47560009, see Appendix A for the Executive Summary for this study), which also found decreased body weights, body weight gains, food consumption, and food efficiency in both sexes at the limit dose (1022/1219 mg/kg/day M/F).

3.3.3 Incidental Oral Exposure ( Short- and Intermediate-Term)

Study selected: 90-day oral toxicity feeding study in rats (OPPTS 870.3100).

MRID Nos. : 47573403 (2008) and 47560007 (2008) Executive Summary: See Appendix A Dose and Endpoint for Risk Assessment: The NOAEL is the point of departure at 349.4/448.0 mg/kg/day M/F (350 mg/kg/da y). The LOAEL is 1044.6/1424.9 mg/kg/day M/F (limit dose )

Page 19 of 76Page 20 of 76 based on decreased body weights, body weight gains, food consum ption, and food efficiency in
both sexes. Uncertainty Factor(s): 100X [10X interspeci es x 10X intraspecies] Comments about selected study: This study is suitable because it is route-specific, addresses all endpoints of concern, and is performed in the most sensitive species at the most sensitive endpoints. The duration of this study is relevant to intermed iate-term exposure and is also protective of short-term exposures. Also, the resu lts of this study with aminocyclopyrachlor are
consistent with those of a similar 870.3100 Gu ideline study with aminocyclopyrachlor-methyl (MRIDs 47560008 and 47560009, see Appendix A for the Executive Summary for this study), which also found decreased body weights, body weight gains, food consumption, and food efficiency in both sexes at the limit dose (1022/1 219 mg/kg/day M/F). Long- term incidental oral exposures are not anticipated based on the proposed use pattern.

3.3.4 Dermal Absorption

There are no dermal absorption studies for am inocyclopyrachlor. Therefore, a conservative default dermal absorption f actor of 100% was used.

3.3.5 Dermal Exposure (Short and Intermediate-Term)

No dermal endpoint was identified because no toxicity was observed in a 28-day dermal toxicity study (OPPTS 870.3200) at the limit dose. A 90-day dermal toxicity study was not available. The requirement for a 90-day dermal toxicity study was waived because the 28-day dermal toxicity study is considered su itable for long-term exposures a nd all endpoints of concern were assessed (J. Ryman, May 13, 2009, D364576).

3.3.6 Inhalation Exposure (Short and Intermediate-Term)

Study selected: 90-day oral toxicity feeding study in rats (OPPTS 870.3100).

MRID Nos. : 47573403 (2008) and 47560007 (2008) Executive Summary: See Appendix A Dose and Endpoint for Risk Assessment: The NOAEL is the point of departure at 349.4/448.0 mg/kg/day M/F (350 mg/kg/da y). The LOAEL is 1044.6/1424.9 mg/kg/day M/F (limit dose ) based on decreased body weights, body weight gains, food consum ption, and food efficiency in
both sexes. Uncertainty Factor(s): 100X [10X interspeci es x 10X intraspecies] Comments about selected study: A route-specific study of suita ble duration was not available. Therefore, a subchronic oral t oxicity study was used. This st udy was considered suitable because significant inhalation exposure is not an ticipated for the proposed use patterns due to low volatility, outdoor uses, and application met hods that are not anti cipated to generate respirable aerosols. Long-term inhalation expo sures are not anticipated based on the proposed
use pattern.3.3.7 Level of Concern for Margin of Exposure

Route Short-Term

(1 - 30 Days) Intermediate-Term

(1 - 6 Months)

Occupational (Worker) Exposure

Dermal NA NA

Inhalation 100 100

Residential Exposure

Dermal NA NA

Inhalation 100 100

Incidental Oral 100 100
NA=Not applicable because no endpoint was identified

3.3.8 Recommendation for Aggregat e Exposure Risk Assessments

Quantitative, aggregate exposure and risk assessm ents for aminocyclopyrachlor are not required for the proposed (non-food) use patterns because Food Quality Protection Act (FQPA) considerations do not apply. However, the po tential for significant aggregate exposures and
risks are estimated in this risk assessment. Since the oral and inhalation endpoints are based on the same effects (e.g., decreased bod y weights), it is appropriate to combine those exposures and
risks.

3.3.9 Consideration of Carcinogenic Potential

Aminocyclopyrachlor and aminocycl opyrachlor-methyl are considered to have low potential to cause chronic toxicity or carci nogenicity. No evidence of genotoxic effects were observed in mutagenicity studies in vitro for aminocyclopyrachlor and aminocyclopyrachlor-methyl or in

vivo for aminocyclopyrachlor. No evidence of ta rget organ toxicity was observed in oral subchronic studies for aminocyclopyrachlor and aminocyclopyrachlor-methyl at doses exceeding the limit dose. Therefore, cancer risk was not assessed.

.

Page 21 of 763.3.10 Summary of Toxicological Doses a nd Endpoints for Use in Human Risk
Assessments

Table 3.3.10.1 Summary of Toxicological Doses and Endpoints for Aminocyclopyrachlor for Use in Dietary and Non-Occupational (R esidential) Human Health Risk Assessments

Exposure/
Scenario Point of Departure Uncertainty

Factors RfD, PAD,
Level of
Concern for
Risk

Assessment Study and Toxicological Effects

Acute Dietary (General Population, including
Females 13-49
and Infants and Children) NA
No hazard

was identified. NA NA Acute Neurotoxicity-rat (870.6200a) NOAEL = 2000 mg/kg/day. No acute neurotoxicity.

Chronic Dietary (>6 months,
General Population, including
Females 13-49
and Infants and Children ) NOAEL = 350 mg/kg/day UF A = 10x

UF H = 10x

UF S = 10x RfD= 0.35 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes

Incidental
Oral ShortTerm (1-30 days) NOAEL=

350 mg/kg/day UF A = 10 x

UF H =10 x The LOC is

3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes

Incidental
Oral
IntermediateTerm (1-6 months) NOAEL=

350 mg/kg/day UF A = 10 x

UF H =10 x The LOC is

3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes

Dermal ShortTerm (1-30 days) NA
No hazard

was identified. NA NA 28-Day Dermal Toxicity- rat (870.3200) NOAEL = 1000 mg/kg/day. No dermal toxicity.

Dermal
IntermediateTerm (1-6 months) NA
No hazard

was identified. NA NA 28-Day Dermal Toxicity- rat (870.3200) NOAEL = 1000 mg/kg/day. No dermal toxicity.

Page 22 of 76Page 23 of 76 Table 3.3.10.1 Summary of Toxicological Doses and Endpoints for Aminocyclopyrachlor for Use in Dietary and Non-Occupational (R esidential) Human Health Risk Assessments

Exposure/
Scenario Point of Departure Uncertainty

Factors RfD, PAD,
Level of
Concern for
Risk

Assessment Study and Toxicological Effects

Inhalation
Short- Term (1-30 days) NOAEL=350 mg/kg/day (inhalation
and oral are
assumed to
be equivalent) UF A = 10 x

UF H =10 x Residential
LOC for
MOE = 100 is

3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes

Inhalation
IntermediateTerm (1-6 months) NOAEL=350 mg/kg/day (inhalation
and oral are
assumed to
be equivalent) UF A = 10 x

UF H =10 x Residential
LOC for
MOE = 100 is

3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes Cancer (oral, dermal, inhalation) NA

Point of Departure (POD) = A data point or an estimated poin t that is derived from observed dose-response data and used to mark the beginning of extrapolation to determine risk associated with lower en vironmentally relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies). UF L = use of a LOAEL to extrapolate a

NOAEL. UF S = use of a short-term study for long-term risk assessment. RfD = reference dose. MOE = margin of exposure. LOC = level of con cern. NA = not applicable.Table 3.3.10.2 Summary of Toxicological Doses and Endpoints for Aminocyclopyrachlor for Use in Occupational Huma n Health Risk Assessments

Exposure/
Scenario Point of Departure Uncertainty

Factors Level of Concern
for Risk

Assessment Study and Toxicological Effects

Dermal ShortTerm (1-30 days) NA
No hazard

was identified NA NA 28-Day Dermal Toxicity- rat (870.3200) NOAEL = 1000 mg/kg/day. No dermal toxicity.

Dermal
IntermediateTerm (1-6 months) NA
No hazard

was identified NA NA 28-Day Dermal Toxicity- rat (870.3200) NOAEL = 1000 mg/kg/day. No dermal toxicity.

Inhalation
Short-Term (1-30 days) NOAEL=350 mg/kg/day (inhalation
and oral are
assumed to
be equivalent) UF A = 10 x

UF H =10 x Occupational
LOC for MOE =
100 is 3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes

Inhalation
Intermediateterm (1-6 months) NOAEL=350 mg/kg/day (inhalation
and oral are
assumed to
be equivalent) UF A = 10 x

UF H =10 x Occupational
LOC for MOE =
100 is 3.5 mg/kg/day 90-Day Oral Toxicity Feeding-rat (870.3100)

LOAEL = 1045 mg/kg/day (limit dose) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes Cancer (oral, dermal, inhalation) NA

Point of Departure (POD) = A data point or an estimated poin t that is derived from observed dose-response data and used to mark the beginning of extrapolation to determine risk associated with lower en vironmentally relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intrasp ecies). MOE = margin of exposure. LOC = level of concern. NA = not applicable.

4.0 Public Health and Pesticide Epidemiology Data

Aminocyclopyrachlor is a new active ingredient that has not been re gistered for use. There are no public health or epidemiological data.

Page 24 of 765.0 Dietary Exposure/Risk Characterization

All of the proposed uses for aminocyclopyrachl or are non-food. Therefore, the only dietary exposures considered in th is assessment are from dr inking water exposures to aminocyclopyrachlor and environmental degradates.

5.1. Environmental Degradation

5.1.1 Stability, mobility, and degradates

The following information on environmental stability and degrad ation products of aminocyclopyrachlor are summarized from EFED ’s “Drinking Water Degr adates Identification Memorandum for Aminocyclopyrachlor” memora ndum (C. Koper, August 25, 2009, D368339).

Aminocyclopyrachlor is non-volatile and highly soluble in water, wh ich indicates that dissipation of aminocyclopyrachlor in the en vironment is expected to occur predominantly via runoff and leaching. Terrestrial field dissipation studies conducted in the continental United States and Canada showed that dissipation occurred with half-lives ranging from 22 to 126 days. Aminocyclopyrachlor is characterized as being modera tely mobile to slightly mobile in test soils based on the adsorption of aminocyclopyrachlor to test soils in batch equilibrium studies. Aminocyclopyrachlor was detected at soil depths of 70 – 90 cm at 365 days, indicating that leaching of residues into groundwater may occur.

Aminocyclopyrachlor is environmentally persistent in diverse environments. It persists in aerobic aquatic environments with a dissipation time of greater than 100 days and in aerobic
terrestrial environments with a half-life of 315 days. It is al so stable in anaerobic aquatic environments with a half life of 1733 days and in anaerobic terrestrial envi ronments with a halflife of 6932 days.

The major route of degradation of aminocyclopyr achlor is abiotic via aq ueous photolysis with a half-life of l.2 days in shallow, clear, and well-lit natural (pH 6.2) water bodies and 7.8 days in pH 4 buffer solution. However, it is slowly phot olyzed on soil, with a half-life of 129 days. Aminocyclopyrachlor is stable to hydrolysis at pH 4 and 7. At pH 9, the half-life was calculated to be at least 34.7 days, however , the possibility that the com pound does not degrade at this pH
could not be ruled out due to mass balance issues.

The major environmental degradates of am inocyclopyrachlor include IN-LXT69, IN-QFH57, IN-Q3007, IN-V0977, IN-YY905, CO 2 and an unidentified a queous photoproduct. The structures of these degradates are listed in Appendix C.

5.1.2 Toxicity Profile of Major Degradates

The following information was obtained from HE D’s “Aminocyclopyrachlor. Report of the Residues of Concern Knowledgebase Subcommitt ee (ROCKS)” memorandum (from G. Kramer, October 15, 2009, D370638). The toxicity profiles of aminocyclopyrachlor and the five major

Page 25 of 76environmental degradates [(IN-LXT69, 5-chloro -2-cyclopropyl-pyrimidin-4-ylamine); (INQFH57, 4-cyano-2-cyclopropyl-1H-imid azole-5-carboxylic acid); (IN-Q3007, cyclopropanecarboxamide); (IN-V0977, cycl opropane carboxylic acid); (IN-YY905, cyclopropanecarboximidamide)] were determined by structure-activity relationship (SAR) analysis using DEREK for Window s (Version 11.0.0). Four of the degradates (IN-LXT69, INQFH57, IN-V0977, IN-YY905) were excluded as resi dues of concern. However, structural alerts and studies in the general scientific lite rature indicated that the environmental degradate IN-V0977 (cyclopropane car boxylic acid) has a different mode of toxicity than the parent compound.

The toxicity of IN-V0977 (cyclo propane carboxylic acid) was addressed by the registrant in a position paper (MRID 47898501) describing what is known about the toxicity of cyclopropane carboxylic acid from the scientific literature and other sources. This position paper was evaluated in a memorandum (fro m J. Ryman, December 31, 2009, D371431) entitled “Toxicity assessment of IN-V0977 (cyclopr opane carboxylic acid)”. The mechanism of toxicity of cyclopropane carboxylic acid has been identified by extensiv e study of the drug panadiplon, which is metabolized to cyclopropane carboxylic acid after oral administration. The mechanism is severe impairment of mitochondrial func tion that causes decreased energy production in diverse organs, with the liver being highly sens itive. The toxic endpoint of concern to the Agency for cyclopropane carboxylic acid was identified as microve sicular steatosis, which can result in liver failure, pancreatitis, kidney failure , coma, and death. The health effects associated
with microvesicular steatosis tend to be more a dverse than those associated with macrovesicular steatosis (accumulation of large fat droplets in cells) in which m itochondrial function is not as compromised, although both can cause inflammati on and scarring in the liver. The most sensitive species in which to observe hepatic microvesicu lar steatosis resulting from cyclopropane carboxylic acid e xposure is the rabbit.

5.1.3 Degradates of Concern

One degradate of concern, cyclopropane carboxylic ac id, has been identified. An acute RfD of 0.0026 mg/kg/day and a chronic RfD of 0.00087 mg/kg/day were determined based on a 2-week oral (gavage) study published in the general sc ientific literature (MRID 47916803). This study investigated the toxicity of pa nadiplon, which is metabolized to cyclopropane carboxylic acid (the toxic entity) in the most sensitive sp ecies (the rabbit). The most sensitive endpoint was hepatic steatosis with a dose-related increase in the incidence and severity of liver damage. No NOAEL was identified, and so a LOA EL of 10 mg/kg/day was us ed as the point of departure (POD). This POD for panadiplon wa s converted to a POD of 2.55 mg/kg/day for cyclopropane carboxylic acid, base d on molecular weights (337.35 g/mole for panadiplon and 86.09 g/mole cyclopropane carboxylic acid) and a mole ratio of 1 mo le of cyclopropane carboxylic acid/mole panadiplon, and assuming 100% conversion of panadi plon to cyclopropane carboxylic acid. Since there is ev idence that hepatic steatosis can occur after acute exposure (1-3 days), acute dietary exposure wa s assessed using this same study. Uncertainty factors used for acute dietary exposures were 10-fold for intras pecies differences, 10-fold for interspecies differences, and 10-fold for extrapolating from a LOAEL to NOAEL. For chronic dietary exposures, an additional 3X uncertainty factor was added for extrapolation from a 14 day study to chronic exposure (J. Ryman, December 31, 2009, D371431). No additional database

Page 26 of 76uncertainty factors were added. The toxicological endpoints used for assessing dietary exposures to this degradate are summarized in Table 5.1.3

.

Table 5.1.3. Summary of Toxicological Dose s and Endpoints for the Environmental Degradate, IN-V0977 (Cyclopropane Carboxylic Acid) for Use in Dietary Human Health
Risk Assessments

Exposure/
Scenario Point of Departure Uncertainty

Factors RfD, PAD,
Level of
Concern for
Risk

Assessment Study and Toxicological Effects

Acute Dietary (All Populations) LOAEL =

2.55 mg/kg/day cyclopropane carboxylic
acid UF A = 10x

UF H = 10x

UF L = 10x RfD=

0.0026 mg/kg/day Rabbit study MRID 47916803 (1998) Non-guideline, oral (gavage) for 14 days 0, 10, 20 mg/kg/day (panadiplon) LOAEL = 10 mg/kg/day based on hepatic
steatosis

Chronic Dietary Long-term (>6 months) LOAEL =

2.55 mg/kg/day cyclopropane carboxylic
acid UF A = 10x

UF H = 10x

UF L = 10x

UF S = 3x RfD=

0.00087 mg/kg/day Rabbit study MRID 47916803 1998) Non-guideline, oral (gavage) for 21 days 0, 10, 20 mg/kg/day (panadiplon) LOAEL = 10 mg/kg/day based on hepatic
steatosis

Cancer (oral) NA Point of Departure (POD) = A data point or an estimated poin t that is derived from observed dose-response data and used to mark the beginning of extrapolation to determine risk associated with lower en vironmentally relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sensitivity among members of the human population (intraspecies). UF L = use of a LOAEL to extrapolate a

NOAEL. UF S = use of a short-term study for long-term risk assessment. RfD = reference dose. NA = not applicable.

5.1.4 Drinking Water Residue Profile

The risk of ground and surface water contam ination and the estimated drinking water concentrations of aminocycl opyrachlor and cyclopropane carboxyl ic acid in surface and ground water for non-crop and turf uses were describe d in a memorandum (from C. Koper, January 08, 2010, D368238) entitled “Drinking wa ter assessment for aminoc yclopyrachlor acid and its degradate cyclopropane carboxylic acid (IN-V09 77) for non-crop and turf use”. Based on the proposed application rates and th e environmental fate properties of aminocyclopyrachlor acid, both surface water and ground water contaminati on may occur from aminocyclopyrachlor acid, but only surface water contamination is expected for the degradate cyclopropane carboxylic acid (IN-V0977).

The risk of water contamination by the parent (a minocyclopyrachlor acid) is primarily associated with stability and mobility of the parent (a minocyclopyrachlor acid) and the toxicity and mobility of the degradate (cyclopropane carboxy lic acid (IN-V0977)). The parent may move from the treated field to ground water through leaching. The primar y route of formation of the degradate is through aqueous photolys is. Since the parent is not su sceptible to soil photolysis (t

Page 27 of 761/2 = 129 days; MRID 47560213), the degradate is not an issue for ground water contamination and exposure to the degradate is most likely to occur from spray drift in aqueous environments.

Due to the difference in toxicities, the parent and degradate were as sessed separately. The Estimated Drinking Water Concentrations (EDWCs) for use in the human health risk assessment are based on the maximum proposed application rates specified in the product labels. For aminocyclopyrachlor acid for non-crop use, a sing le application of 0.284 lbs. a.i./acre can be applied for a yearly maximum application rate of 0.284 lbs. a.i./acre. For turf use, three applications of 0.108 lbs. a.i./acre can be applied with a 30-day application interval for a yearly maximum application rate of 0.324 lbs. a.i./acre. The application rate for the cyclopropane carboxylic acid (IN-V0977) degradate can be calc ulated by multiplying the application rate of the parent (e.g.: 0.284 lbs. a.i./acre) by the fracti on of the maximum detected degradate from the submitted fate studies (0.146; MRID 47560211) then multiplying by the ratio of the molecular weights of the degradate to parent (86.09/213.62) . Following this equation, the maximum single application rate was 0.017 lbs. degradate/acre for non-crop use and 0.006 lbs. degradate/acre for
turf.

Tier I screening models were employed for th is assessment. For surface water, the FIRST ( F QPA I ndex R eservoir S creening T ool, Version1.1.1) model was used to estimate drinking water concentrations. For ground water, the SCI-GROW model (Scree ning Concentration in Ground Water Program Version 2.3) was used to pr edict the maximum acut e and chronic (annual average) concentrations present in shallow ground water.

For drinking water derived from surface water for the parent aminocyclopyrachlor acid, the
FIRST model estimated the acute and chronic (annual average) concentrations at 27.287 ug/L and 16.965 ug/L, respectively. For drinking water derived from surface water for the degradate cyclopropanecarboxylic acid (IN-V0977), the acute a nd chronic (annual average) concentrations are 1.742 ug/L and 1.246 ug/L, respectively. Fo r drinking water derive d from ground water for the parent aminocyclopyrachlor acid, the SCI-GROW model estimated the ground water concentration to be 40.2 ug/L. This concentra tion should be used for the acute and chronic values. In addition, since the parent is not susceptible to soil photolysis (t 1/2 = 129 days; MRID 47560213), the degradate is not an issue for gr ound water contamination; therefore, no SCIGROW modeling was performed on the degradate.

The estimated surface water concentrations of the parent aminocyclopyrachlor acid and its degradate cyclopropane carboxylic acid (IN-V09 77) for the use on non-crop applications and turfgrasses are summarized in Table 5.1.4. The estimated ground water concentrations of aminocyclopyrachlor are also summarized in Table 5.1.4 . Selected values from Table 5.1.4
were used to calculate acute and/or chronic dietary exposures to aminocyclopyrachlor and its degradate from drinking water as described in Section 5.2.

Page 28 of 76Table 5.1.4 Estimated Drinking Water Con centrations (EDWCs) resulting from applications of aminocyclopyrachlor acid a nd the degradate cyclopropane carboxylic acid (IN-V0977) for non-crop and turf use.

Drinking

Water
Source (Model) Compound Use Method Application

Rate (interval

between applications) Adjustme

nt Factor 2 Peak Day (acute)
Concentrati

on (μg/L) Annual Average (chronic)
Concentrati

on (μg/L)

Aerial 1 app @ 0.284
a.i./acre

(NA) 25.576 15.904

NonCrop
Ground 1 app @ 0.284
a.i./acre

(NA) 25.641 15.943 Aminocyclopyrachl
or Acid

Turf Granular 3 app @ 0.108
a.i./acre (30 days) 27.287 16.965

NonCrop 1 app @ 0.017 degradate/acre (NA) 1.515 1.084 Surface

Water (FIRST)

Cyclopropane carboxylic Acid (IN-V0977) Turf Granular

1 3 app @ 0.006 degradate/acre (30 days) 0.87

1.742 1.246

NonCrop --- 1 app @ 0.284
a.i./acre

(NA) --- 35.2 35.2 Ground

Water(SCIGROW) Aminocyclopyrachl
or Acid

Turf --- 3 app @ 0.108
a.i./acre (30 days) --- 40.2 40.2

Bold values denote maximum Estimated Drinking Water Concentrations (EDWCs)

1 Granular method of application was selected for the degradate (Drift = 0.0% and Application Efficiency = 100%). All applications are liquid unless otherwise noted.

2 Adjustment Factors: PCA = Percent Crop Area NA = Not Applicable

5.2 Dietary Exposure and Risk

An acute and chronic dietary exposure analysis was performed for drinking water only, since
there are no food uses for this re gistration action. The analysis was performed using the Dietary Exposure Evaluation Model DEEM-FCIDTM, Versi on 2.03. This model uses food consumption data from the U.S. Department of Agricu lture’s Continuing Surveys of Food Intakes by Individuals (CSFII) from 1994-1996 along with a s upplemental children’s survey from 1998. Aminocyclopyrachlor is a new active ingredient (a.i.) and, as such, is not registered for any food or non-food uses. The proposed use is on turf and ornamentals. As there are no registered or proposed food uses for aminocyclopyrachlor, diet ary exposure to the chemical will be through drinking water only. Dietary exposures to bot h aminocyclopyrachlor and the environmental degradate, IN-V0977 (cyclopropane carboxylic acid) from drinking water were considered in a memorandum (from T. Morton, January 19, 201 0, D369058) entitled “Aminocyclopyrachlor:
Revised Acute and Chronic Diet ary (Drinking Water Only) Exposur e Analysis for the Section 3 Registration Action”.

Page 29 of 76Page 30 of 76 The Estimated Drinking Water Con centration (EDWC) used in the acute and chronic dietary risk assessment was provided by the corrected EFED (Memo, D368238, C. Koper, 01/08/2010). The annual average EDWC for chronic exposure asse ssment was incorporated directly into the dietary assessment in the food categories “water, direct, all sources” a nd “water, indirect, all sources.” The EDWCs for aminocyclopyrachlor were generated with the model FIRST for surface water and SCI-GROW for groundwater. Modeled surface and groundwater EDWCs are based on the label application rate to turf and non-crop. The FIRST annual average surface water estimate of 16.965 ppb is less than the SCI- GROW groundwater estimate of 40.2 ppb. As a result, the ground water estimate was used in th e chronic dietary analysis for the parent. For the degradate, an annual peak EDWC of 1.742 ppb wa s used for the acute dietary analysis and an annual average EDWC of 1.246 ppb was used for the chronic dietary analysis. Additional information concerning the water models is available at the EPA internet site: http://www.epa.gov/oppefed/models/water/

. Dietary risk assessment incorporat es both exposure and toxicity of a given pesticide. For acute and chronic assessments, the risk is expresse d as a percentage of a maximum acceptable dose (i.e., the dose that HED has concluded will result in no unreasonable adverse health effects). For chemicals that have only non-food us es, this dose is referred to as the reference dose (RfD). The RfD is equivalent to the poi nt of departure (e.g., NOAEL, L OAEL) divided by the required uncertainty factors.

For acute and non-cancer chronic ex posures to non-food-use pestic ides, HED is concerned when estimated dietary risk exceeds 100% of the RfD. HED is generally concerned when estimated
cancer risk exceeds one in one million. Referen ces that discuss the acute and chronic risk assessments in more detail are available on the EPA/pesticides website: “Available Information on Assessing Exposure from Pesticides, A User’s Guide,” 6/21/2000, web link: http://www.epa.gov/fedrgstr/EPA-PEST/2000/July/Day-12/6061.pdf ; or see SOP 99.6 (8/20/1999).

5.2.1 Acute Dietary Exposure/Risk

An acute dietary endpoint was not identifie d for the parent aminocyclopyrachlor ( Table 5.2.1 ). An acute dietary endpoint was identified for the environmental degradate IN-V0977 ( Table
5.2.2 ). The most highly exposed population subgroup is All Infants (<1 year old) which utilizes 13 % of the acute RfD (aRfD) for the environmen tal degradate IN-V0977. The risk estimates for the general U.S. population and all other regul ated population subgroups are below HED’s level of concern (<100% of the cRfD) for the environmental degradate IN-V0977.

5.2.2 Chronic Dietary Exposure/Risk

A chronic dietary endpoint was identified for aminocyclopyrachlor. Th e most highly exposed population subgroup is All Infants (<1 year old) which utilizes <1% of the chronic reference dose (cRfD). A chronic dietary e ndpoint was also identified for the environmental degradate INV0977. The most highly exposed population subgroup is All Infants (<1 year old) which uses
9.9% of the cRfD. The risk estimates for the general U.S. population and all other regulated population subgroups are below HED’s level of con cern (<100% of the cRfD) for both the parent aminocyclopyrachlor and the environmental degradate (IN-V0977).Table 5.2.1 Results of Acute and Chronic Dr inking Water Exposure and Risk Estimates for Aminocyclopyrachlor

Acute Dietary Chronic Dietary Cancer

Population Subgroup* Dietary Exposure (mg/kg/day) % a PAD Dietary Exposure (mg/kg/day) % c PAD Dietary Exposure (mg/kg/day) Risk

General U.S. Population 0.000847 <1

All Infants (< 1 year old) 0.002778 <1

Children 1-2 years old 0.001258 <1

Children 3-5 years old 0.001178 <1

Children 6-12 years old 0.000812 <1

Youth 13-19 years old 0.000612 <1

Adults 20-49 years old 0.000791 <1

Adults 50+ years old 0.000832 <1

Females 13-49 years old Not Applicable: No Acute Dietary Endpoint
Was Identified

0.000788 <1 Not Applicable: No Cancer Dietary Endpoint
Was Identified

Table 5.2.2 Results of Acute and Chronic Dr inking Water Exposure and Risk Estimates for Degradate (IN-V0977)

Acute Dietary

95 th percentile Chronic Dietary Cancer

Population Subgroup* Dietary Exposure (mg/kg/day) % a PAD Dietary Exposure (mg/kg/day) % c PAD Dietary Exposure (mg/kg/day) Risk

General U.S. Population 0.000091 3.5 0.000026 3.0

All Infants (< 1 year old) 0.000343 13 0.000086 9.9

Children 1-2 years old 0.000143 5.5 0.000039 4.5

Children 3-5 years old 0.000130 5.0 0.000037 4.2

Children 6-12 years old 0.000091 3.5 0.000025 2.9

0.000074 2.8 0.000019 2.2 Not Applicable: No Acute Dietary Endpoint
Was Identified

Page 31 of 76Page 32 of 76 Table 5.2.2 Results of Acute and Chronic Dr inking Water Exposure and Risk Estimates for Degradate (IN-V0977)

Acute Dietary

95 th percentile Chronic Dietary Cancer

Population Subgroup* Dietary Exposure (mg/kg/day) % a PAD Dietary Exposure (mg/kg/day) % c PAD Dietary Exposure (mg/kg/day) Risk

Youth 13-19 years old

Adults 20-49 years old 0.000084 3.2 0.000025 2.8

Adults 50+ years old 0.000076 2.9 0.000026 3.0

Females 13-49 years old 0.000085 3.3 0.000024 2.8

5.2.3 Cancer Dietary Risk

No cancer endpoint has been identified for amin ocyclopyrachlor or cyclopropane carboxylic acid. Therefore, the cancer risk from dietary exposure were not assessed.

6.0 Residential (Non-Occupational) Exposure/Risk Characterization

The residential risk assessment addresses exposures that individuals receiv e through their use of consumer products that contain aminocyclopyrachl or and through exposures they could receive from frequenting areas that have been previously treated. Reside ntial uses in this registration
action are control of broad leaf and woody species weeds includi ng many terrestrial, riparian invasive, and noxious weeds on lawn/turf. Based on label specific information and information provided by the registrant, resi dential handler exposures are expected to be short- and
intermediate-term in duration. The residential handler and postapplication exposure and risk, based on product labels, is summarized below a nd is also described in a Memorandum entitled “Occupational and Residential Risk Assessment to Support the Request for Registration of Aminocyclopyrachlor, its methyl ester and pot assium salt on Turf and Non-crop areas” (J.S. Miller, January 30, 2010, D372493).6.1 Residential Handler Exposure

Based on label specific information and inform ation provided by the registrant, residential handler exposures are expected to be short- and intermediate -term in duration. Long-term residential handler exposures are not expected.

The Agency identified several residential expos ure scenarios based on the types of equipment and techniques that potentially can be used for aminocyclopyrachlor applications. These
scenarios include:

• Mixing/Loading/Applying

o Low Pressure Handwand: Dry flowable and soluble liquid formulations to
lawn/turf

o Hose-End Sprayer: Dry flowable and sol uble liquid formulations to lawn/turf

o Hand Held Spreader (Belly Grinder): Granular formula tion to lawn/turf

6.1.1. Data and Assumptions for Residential Handler Exposure Scenarios

The following data and assumptions were used to calculate residential handler risks using a Margin of Exposure (MOE) of 100. Daily dose estimates were calculated using relevant application parameters (i.e., rate and area trea ted) along with unit exposures. Exposures were then adjusted for body weight (an average adult body weight of 70 kg was assumed). Routes of residential exposures are dermal and inhalation. Quantification of derm al exposures was not performed because no toxicity was observed in a subchronic dermal toxicity study at the limit dose (1000 mg/kg). Inhalation risks were asse ssed by using an absorption factor of 100% (assuming no respirator use) to calculate dose levels.

6.1.1.1. Unit Exposures

Chemical-specific data for assessing exposure during pesticide handli ng activities were not submitted to the Agency in support of this Sec tion 3 application. Therefore, unit exposure data from the PHED Surrogate Exposure Gu ide dated August 1998 were used.

6.1.1.2. Area Treated

It is Agency policy to assume a lawn/turf treatment area of 0.5 acres per day for all residential
handler scenarios.

6.1.1.3. Application Rate

Aminocyclopyrachlor (as parent acid and potassium salt) and aminocyclopyrachlor -methyl are applied in three different formulations: a wa ter dispersible granular , a soluble liquid, and a granular. Labels were chosen th at that were representative of th ese different formulations and all exposure scenarios, and while yielding the maxi mum application rate for exposure assessment (i.e. would be the most conservative). These application rates range from a minimum of 0.07 lbs acid equivalent/acre to a maximum of 0.10 lbs acid equivalent/acre ( Table 2.1.1 ).

Page 33 of 766.1.1.4. Results and Conclusions

Results of the residential handler risk assessment are summarized in Table 6.1.1. All exposure
scenarios are for lawn/turf. For all residential exposu re scenarios, MOEs were greater than 100 (MOE >100), and therefore are not of concern.

Table 6.1.1 Summary of Residential Short a nd Intermediate-Term Risk Assessment for Aminocyclopyrachlor (Acid and Potassium Salt) and Aminocyclopyrachlor-Methyl

Exposure Scenario Application

Rate (lb ae/A) Area

Treated (A/day) Inhalation
Unit Exposure ( μ g/lb ai) Inhalation Daily Dose (mg/kg/day) Inhalation
Short/IntermediateTerm MOE

Open Mixing, Loading, and Applying

Low Pressure

Handwand (Soluble Liquid) 30 0.000015 23,000,000

Open Mixing, Loading, and Applying Hose-end Sprayer

(Dry Flowable) 0.07

17 0.0000085 41,200,000

Open Mixing, Loading, and Applying Belly Grinder

(Granular) 0.10 0.5

62 0.000048 7,300,000

ae=acid equivalent; A=acre; ai=active ingredient

6.2. Residential Postapplication Exposure

Individuals of varying ages and life stages can potentially be exposed to aminocyclopyrachlor when they do activities in areas that have been previously treated. Post-application exposure
scenarios include scenarios that are relevant to toddlers, which were considered. These scenarios are non-dietary ingestion exposures resulting from transfer of pes ticide resides on treated areas to hands that may put in the mouth (hand-to-mouth transfer), transfer of pesticide residues on treated areas to objects that may be put in the mouth (e.g. object-to-mouth), and ingestion of soil from pesticide treated areas. The postapplica tion exposure and risk, ba sed on product labels, is
summarized below and is also described in a Memorandum entit led “Occupational and
Residential Risk Assessment to Support the Request for Regist ration of Aminocyclopyrachlor, its methyl ester and potassium salt on Turf a nd Non-crop areas” (J.S. Miller, January 30, 2010, D372493).

Page 34 of 76Page 35 of 76 6.2.1. Data and Assumptions for Residential Postapplication Scenarios

The following data and assumptions were used to calculate residential post application risks using a Margin of Exposure (MOE) of 100. Routes of postapplication exposure were assumed to be dermal and oral. Quantification of dermal expos ures was not performed because no toxicity was observed in a subchronic dermal toxicity study at the limit dose (1000 mg/kg). Oral exposures were determined by calculating daily dose esti mates from hand-to-mouth, object-to-mouth, and soil ingestion exposures. Exposures were then adjusted for body weight (a child’s body weight of 15 kg was assumed). Oral exposures were th en added to arrive at a combined MOE.

6.2.2. Results and Conclusions

Results of the residential postapplicati on risk assessment are summarized in Table 6.2.1. For all residential exposure scen arios, combined MOEs for Shor t-Term and Intermediate-Term exposure were greater than 100 (MOE > 100) and therefore are not of concern.

Table 6.2.1.: Toddler Residential Risk Esti mates for Post-Application Exposure to Aminocyclopyrachlor (Acid and Potassium Salt) and Aminocyclopyrachlor-Methyl

Exposure Scenario TC

cm 2 /hr Route of Exposure Application Rate MOE at Day 0 Combined MOE 1

Ingestion

Outdoors S-Term Int-Term

Hand to Mouth Activity on Turf 234,000 493,000

Object to Mouth Activity on Turf 938,000

Soil Ingestion N/A Oral 0.1

70,000,000 322,000

1 Combined MOE value shown is for Intermediate-Term, but is inclusive of Short-Term.

6.3 Spray Drift

Spray drift is always a potential source of expos ure to residents nearby to spraying operations. This is particularly the case with aerial appl ication, but, to a lesser ex tent, could also be a potential source of exposure from th e ground application method employed for aminocyclopyrachlor. The Agency has been work ing with the Spray Drift Task Force, EPA Regional Offices and State Lead Agencies for pes ticide regulation and othe r parties to develop the best spray drift management practices. On a chemical by chemical basis, the Agency is now requiring interim mitigation measures for aerial a pplications that must be placed on product labels/labeling. The Agency has completed its ev aluation of the new database submitted by the Spray Drift Task Force, a membership of U.S. pe sticide registrants, and is developing a policy on how to appropriately apply the da ta and the AgDRIFT computer model to its risk assessments for pesticides applied by air, orch ard airblast and ground hydraulic me thods. After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce off-target drift with specific products with significant ri sks associated with drift.7.0 Aggregate Risk Assessment s and Risk Characterization

The potential for significant aggregate exposur es to aminocyclopyrachlor from dietary and residential uses relative to non-aggregate expos ures was considered. The highest estimated residential exposure (0.000048 mg/kg/day via in halation during mixing, loading, and applying a granular formulation with a belly grinder, Table 6.1.1 ) combined with the highest estimated dietary exposure (0.002778 mg/kg/ day for All Infants < 1 year, Table 5.2.1 ). This combined
value of 0.003 was over 1000- fold lower than the point of departure of 3.5 mg/kg/day, based on the most conservative level of concern for margin of exposure (350 mg/kg/day with MOE=100). This estimate indicates that aggregate expos ures to aminocyclopyrachlor will not result in significantly increased risk rela tive to non-aggregate exposure.

8.0 Occupational Exposure/Risk Pathway

This section of the risk assessment addresses exposures to individuals who are exposed to aminocyclopyrachlor as part of their employment. These exposures can occur because people have contact with aminocyclopyrachlor while using commercial products containing aminocyclopyrachlor (i.e., handlers) or by being in areas that have been previously treated (post-application).

Occupational uses in this regi stration action are general weed and brush control on private, public and military lands including un-cultivat ed non-agricultural areas such as airports, highways, railroads, golf courses, lumber yards, wild life habitats, multi family residential complexes, recreation areas, sod farms, utility ri ghts of way, and residential lawns. Based on label specific information and information pr ovided by the registrant, occupational handler exposures are expected to be short- and intermediate-term in duration.

The occupational handler and post-application e xposure and risk, based on product labels, is
summarized below and is also described in a Memorandum entitle d “Occupational and
Residential Risk Assessment to Support the Request for Regist ration of Aminocyclopyrachlor, its methyl ester and potassium salt on Turf a nd Non-crop areas” (J.S. Miller, January 30, 2010, D372493).

8.1 Short-Term and Intermediate-Term Handler Risk

Based on label specific information and inform ation provided by the registrant, occupational handler exposures are expected to be short- and intermediate -term in duration. Long-term occupational handler exposu res are not expected.

The Agency completes occupational handler risk a ssessments using scenarios as the basis for the
calculations as described in the U.S. EPA Guidelines for Exposure Assessment . For commercial pesticide products, the Agency cat egorizes handler exposures base d on the kinds of formulations (e.g., liquids), the kinds of equipment used to make applications (e.g., types of handheld equipment), the nature of the task (e.g., mixing/loading, applyi ng, or both combined), and the level of personal protection used. Identifying the durat ion of exposure is also a critical element in the development of a risk assessment to ensure that the proper hazard component is used.

Page 36 of 76The Agency identified several major occupati onal exposure scenarios based on the types of equipment and techniques that potentially can be used for aminocyclopy rachlor applications.
These scenarios include:

• Mixing/Loading

o Groundboom: Dry flowable and soluble li quid formulations to non-crops, golf courses, sod farms, and lawn/turf

o Aerial (fixed and non-fixed wing): Dry flowable formulation to non-crops

o LCO handgun: Water dispersible granul es and soluble liquid formulations to non-crops, golf courses, sod farms, and lawn/turf

o Right of way sprayer: Wate r dispersible granules and soluble liquid formulations to non-crops, golf courses, sod farms, and lawn/turf

o Push type spreader: Granular formul ation to golf courses, sod farms, and
lawn/turf

o Tractor drawn broadcast spreader: Granul ar formulation to golf courses, sod farms, and lawn/turf

o Push cyclone spreader: Granular formul ations to golf courses, sod farms, and
lawn/turf

• Applying

o Groundboom: Dry flowable and soluble li quid formulations to non-crops, golf courses, sod farms, and lawn/turf.

o Aerial (fixed an non-fixed wing): Dr y flowable formulation to non-crops

o LCO handgun: Water dispersible granules and soluble liquid formulations to non-crops, golf courses, sod farms, and lawn/turf

o Right of way sprayer: Wate r dispersible granules and soluble liquid formulations to non-crops, golf courses, sod farms, and lawn/turf

o Tractor drawn broadcast spreader: Granul ar formulation to golf courses, sod farms, and lawn/turf

• Flagging

o Aerial (fixed and non-fixe d wing): Dry flowable formulation to non-crops

8.1.1. Data and Assumptions for Occ upational Handler Exposure Scenarios

The following data and assumptions were used to calculate occupational handler risks using a Margin of Exposure (MOE) of 100. Daily dose estimates were calculated using relevant application parameters (i.e., rate and area trea ted) along with unit exposures. Exposures were then adjusted for body weight (an average adult body weight of 70 kg was assumed). Routes of occupational exposures are dermal and inhalation. Quantification of dermal exposures was not performed because no toxicity was observed in a subchronic dermal toxicity study at the limit dose (1000 mg/kg). Inhalation risks were asse ssed by using an absorption factor for 100% (assuming no respirator use) to calculate dose levels.

8.1.1.1. Unit Exposures

Chemical-specific data for assessing exposure during pesticide handli ng activities were not submitted to the Agency in support of this Sectio n 3 application. It is HED policy to use data from the Pesticide Handlers Exposure Database (PHED) Version 1.1 to assess handler exposures

Page 37 of 76Page 38 of 76 for regulatory actions when chemical-specific data are not available (HED Science Advisory Council for Exposure, SOP Number .007, January 1999).

8.1.1.2. Area Treated

Assumptions made regarding the number of acres of land treated per day for different mixing, loading, and application scenarios are described in a Standard Operating Procedure (SOP) of the HED Exposure Science Advisory Committee (Num ber 9.1). These assumptions relevant to occupational handler scenario s indicated by product labels are summarized below:

• 40 acres per day for mixing/ loading, and appl ying for lawn/turf and golf courses when using groundboom equipment

• 80 acres per day for mixing/loading and a pplying for non-crops and sod farms with groundboom equipment

• 350 acres per day for mixing/loading, applyi ng and flagging for non-crops with aerial equipment

• 5.0 acres per day for application for non-crop, lawn/turf, golf courses, and sod farms with LOC handgun equipment and right of way sprayers

• 100 acres per day for mixing and loading fo r non-crop and lawn/turf with LOC handgun equipment. (Based upon mixing and loading of 20 trucks that wi ll apply 5 acres of formulation per day).

• 5.0 acres per day for loading and applying for sod farm and golf courses with a push type spreader

• 40 acres per day for application for sod fa rms and golf courses with a tractor drawn broadcast spreader or push cyclone spreader

8.1.1.3. Application Rate

Aminocyclopyrachlor (parent acid and potassium salt) and aminocyclopyrachlor-methyl are applied in three different formulations: a wa ter dispersible granular , a soluble liquid, and a granular. Labels were chosen th at that were representative of th ese different formulations and all exposure scenarios, and while yielding the maxi mum application rate for exposure assessment (i.e. would be the most conservative). Du Pont labels DPXKJM44 80XP Herbicide/EPA Reg. No. 352 – TOE, DPX-MAT28 240SL Turf Herb icide/EPA Reg No. 352-TOG, and DuPontTM
DPX-MAT28 0.064G Lawn Herbicide + Fertiliz er/EPA Reg No. 352-TOT satisfied this criterion. These application rates range from a minimum of 0.07 lbs acid equivalent/acre to a maximum of 0.28 lbs acid equivalent/acre.8.1.1.4. Results and Conclusions

Results of the occupational handler risk assessment are summarized in Table 8.1.1 . Inhalation Unit Exposure calculations were based on no re spiratory protection. For all occupational exposure scenarios, MOEs were gr eater than 100 (MOE >100), and th erefore are not of concern.

Table 8.1.1. Summary of Occupational Short a nd Intermediate-Term Risk Assessment for Aminocyclopyrachlor (Acid and Potassium Salt) and Aminocyclopyrachlor-methyl

Exposure Scenario Crops Application

Rate (lb ae/A) Area

Treated (A/day) Inhalation
Unit Exposure ( μ g/lb ai) Inhalation Daily Dose (mg/kg/day) Inhalation
Short/
IntermediateTerm MOE

Open Mixing and Loading
Groundboom (Dry Flowable) 0.77 0.0002464 1,400,000

Applying Sprays with
Groundboom (Open Cab) (Dry Flowable) Non-Crop 0.28

0.74 0.0002368 1,500,000

Open Mixing and Loading
Groundboom (Dry Flowable) 0.77 0.0000616 5,700,000

Applying Sprays with
Groundboom (Open Cab) (Dry Flowable) Turf /Sod

Farm 80

0.74 0.0000592 5,900,000

Open Mixing and Loading
Groundboom (Liquid) 0.07

1.2 0.000048 7,300,000

Applying Sprays with
Groundboom (Open Cab)

(Liquid) Turf/Lawn
Golf

Course

. 40

0.74 0.0000296 12,000,000

Open Mixing and Loading
Groundboom (Liquid) 1.2 0.000096 3,600,000

Applying Sprays with
Groundboom (Open Cab)

(Liquid) Turf/Sod

Farm 0.07

80

0.74 0.0000592 5,900,000

Page 39 of 76Table 8.1.1. Summary of Occupational Short a nd Intermediate-Term Risk Assessment for Aminocyclopyrachlor (Acid and Potassium Salt) and Aminocyclopyrachlor-methyl

Inhalation Application Inhalation Area Inhalation Exposure Scenario Crops Rate (lb ae/A) Treated (A/day) Unit Short/ Daily Dose Exposure Intermediate- (mg/kg/day) ( μ g/lb ai) Term MOE

Mixing/Loading LOC Handgun (Dry Flowable) Non-crop 0.28 100 1 0.77 0.000308 1,100,000

Applying LOC Handgun (Dry Flowable) Non-crop 0.28 5 1.4 0.000028 13,000,000

Mixing/Loading LOC Handgun (Liquid) 100 1 1.2 0.00012 2,900,000

Applying LOC Handgun (Liquid) Turf/Lawn
Sod Farm
Golf

Course 0.07

5 1.4 0.000007 50,000,000

Mixing/Loading
Aerial (Dry Flowable) 0.77 0.001078 320,000

Applying Sprays
Aerial (Enclosed Cockpit)

(Dry Flowable) 1.3 0.00182 190,000

Aerial Flagging Non-Crop 0.28 350

0.15 0.00021 1,700,000

Mixing /Loading Push Type Spreader (Granular) 1.7 0.00001 27,000,000

Applying Push Type Spreader (Granular) 5

1.2 0.0000093 38,000,000

Mixing/Loading/Applyi

ng Tractor Drawn Broadcast Spreader (Granular) Sod Farm
Golf

Course 0.108

40 7.3 0.000451 780,000

Page 40 of 76Page 41 of 76 Table 8.1.1. Summary of Occupational Short a nd Intermediate-Term Risk Assessment for Aminocyclopyrachlor (Acid and Potassium Salt) and Aminocyclopyrachlor-methyl

Exposure Scenario Crops Application

Rate (lb ae/A) Area

Treated (A/day) Inhalation
Unit Exposure ( μ g/lb ai) Inhalation Daily Dose (mg/kg/day) Inhalation
Short/
IntermediateTerm MOE

Applying Right of Way Sprayer (Dry Flowable) Non-Crop 0.28 5 3.9 0.000078 4,500,000

Mixing/Loading Right of Way Sprayer (Dry Flowable) Non-Crop 0.28 0.77 0.0000154 23,000,000

Applying Right of Way Sprayer (Soluble Liquid) Turf/Lawn
Sod Farm
Golf

Course 0.07 5

3.9 0.0000195 18,000,000

ae=acid equivalent; A=acre; a.i.=active ingredient

1 100 acres represents an individual mixing an d loading 20 trucks that will apply 5 acres

8.2 Short-Term and Intermediate-Term Postapplication Risk

Postapplication exposures are expe cted to be short-term and intermediate term in duration. Long-term post-application exposures are not exp ected. Routes of occupational exposures are dermal and inhalation. Post-application inhalatio n exposures are expected to be negligible (based on the occupational handler in halation MOE values of (190,000 – 50,000,000) and
therefore were not assessed. Quantification of dermal exposur es was not performed because no toxicity was observed in a subc hronic dermal toxicity study at the limit dose (1000 mg/kg).

9.0 Data Needs and Label Recommendations

9.1 Toxicology

No additional toxicity data are required to asse ss the human health risks of aminocyclopyrachlor for the use patterns described in this risk asse ssment. A repeated dose study in a sensitive species is needed to address the hazard of chronic exposure to the environmental degradate cyclopropane carboxylic acid.

9.2 Occupational and Residential Exposure

No additional data required. Label directions call for a restricted entry interval (REI) of 4 hours. However due to a category III in acute eye irritation, HED recommends a REI of 12 hours and
that all label directions refl ect this change. Labels for 352-TOA, 352-TIU, and 352-TOL do not state application rates, and so HED reco mmends that these labels be revised.Page 42 of 76 10.0 References (Memoranda)

MRID references are listed in Appendix A (secti on A.4). The following Memoranda (listed in order of date) were cited within the main text of this risk assessment:

Waiver request for a 90-day dermal toxicity study (870.3250) and status of the mutagenicity testing database for DPX-MAT28, J. Ryman, May 13, 2009, D364576, TXR 0055180.

PRODUCT CHEMISTRY REVIEW OF: DP X MAT28 Technical Herbicide, A. Abramovitch, August 16, 20009, D357886.

Drinking Water Degradates Iden tification Memorandum for Ami nocyclopyrachlor, C. Koper , August 25, 2009, D368339.

PRODUCT CHEMISTRY REVIEW OF: DPX KJM44 Technical Herbicide , A. Abramovitch , August 25, 2009, D357975.

Aminocyclopyrachlor. Report of the Residue s of Concern Knowledgebase Subcommittee (ROCKS), G. Kramer, October 15, 2009, D370638,

Toxicity assessment of IN-V0977 (cyc lopropane carboxylic acid).J. Ryman
, December 31, 2009, D371413, TXR 0055290.

Drinking water assessment for aminocyc lopyrachlor acid and its degradate cyclopropanecarboxylic acid (IN-V0977) for non-crop and turf use, C. Koper, January 8, 2010,

D368238.

Aminocyclopyrachlor: Revised Acute and Chr onic Dietary (Drinking Water Only) Exposure Analysis for the Section 3 Registrati on Action, T. Morton, January 19, 2010, D372779.

Occupational and Residential Risk Assessment to Support the Request for Registration of Aminocyclopyrachlor, its methyl ester and pot assium salt on Turf and Non-crop areas, J.S. Miller, January 30, 2010, D372493.

Recommended waivers of conditionally required toxicology studies for non-food uses of aminocyclopyrachlor, J. Ryman, February 4, 2010, D373897.Page 43 of 76 Appendix A: Toxicology Assessment

A.1 Toxicology Data Requirements

The requirements (40 CFR Part 158.510) fo r non-food pesticides are listed below :

Technical Test

Required Satisfied

870.1100 Acut e Oral T oxicity................................................... 870.1200 Acute Dermal Toxicity ..............................................

870.1300 Acute Inhalation Toxicity..........................................
870.2400 Prim ary Eye Ir ritation................................................
870.2500 Primar y Dermal Irritation ..........................................
870.2600 Dermal Sensitization.................................................. yes

yes

yes

yes

yes

yes yes

yes

yes

yes

yes

yes

870.3100 Oral Subchronic (rodent) ...........................................
870.3150 Oral Subchronic (n onrodent) ..................................... 870.3200 21-Day Dermal .......................................................... 870.3250 90-Day Dermal ..........................................................

870.3465 90 -Day Inhalation...................................................... CR

CR

no

yes CR yes Waiver recommended 1

yes yes (waived) 2

Waiver recommended 1

870.3700a Developmenta l Toxicity (rodent)............................... 870.3700b Developmental Toxicity (nonrodent)......................... 870.3800 Reproduction ............................................................. yes

yes

yes yes

yes

yes

870.4100a Chronic Toxicity (rodent) ..........................................
870.4100b Chronic T oxicity (nonrodent)....................................

870.4200a Onc ogenicity (rat)...................................................... 870.4200b Oncogenicity (mouse)................................................ CR

CR

CR
CR Waiver recommended 1

Waiver recommended 1

Waiver recommended 1

Waiver recommended 1

870.5100 Mutagenicity —Gene Mutation - bacterial................. 870.5300 Mutagenicity—Gene Mutation - mammalian............ 870.5375 Mutagenicity—In Vitro Chromosomal Aberrations.. 870.5385 Mutagenicity—In Vivo Bone Marrow
Chromosomal ...............................................................................
870.5395 Mutagenicity—In Vivo Erythrocyte Micronucleus ... yes

yes

yes

yes

yes yes

yes

yes yes (waived) 2

yes

870.6100a Acute Dela yed Neurotox. (hen) ................................. 870.6100b 90-Day Neurotoxicity (hen).......................................

870.6200a Acute Neurotox. Screening Battery (rat) ................... 870.6200b 90-Day Neuro. Screening Battery (rat)...................... 870.6300 Develop. Neuro.......................................................... CR

CR

yes

yes CR Waiver recommended 1

Waiver recommended 1

yes

yes

Waiver recommended 1

870.7200 Compan ion animal safety ..........................................

870.7485 Ge neral Meta bolism ..................................................

870.7600 Derm al penetr ation ....................................................
870.7800 Immunotoxicity ......................................................... CR

CR

CR

yes Waiver recommended 1

yes

Waiver recommended 1
yes`

CR=conditionally required

1 Rationale described in a Memorandum entitled “Recommended waivers of conditionally required toxicology studies for non-food uses of aminocyclopyrachlor” (J. Ryman, February 4, 2010, D373897).

2 Rationale described in a Memorandum entitled “Waiver request for a 90-day dermal toxicity study (870.3250) and status of the mutagenicity testing database for DPX-MAT28” ( J. Ryman, May 13, 2009, D364576, TXR 0055180).Page 44 of 76 A.2 Toxicity Profiles

Table A.2.1 Acute Toxicity Profile for Aminocyclopyrachlor technical

Guideline No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral [rat] 47559934 LD 50 >5000 mg/kg IV

870.1200 Acute dermal [rat] 47559935 LD 50 >5000 mg/kg IV

870.1300 Acute inhalation [rat] 47560001 LD 50 >5.4 mg/L IV

870.2400 Acute eye irritation [White New Zealand rabbit] 47560002 Mild irritant III

870.2500 Acute dermal irritation [rabbit] 47560003 Non-irritant IV

870.2600 Skin sensitization [Guinea Pig] 47560004 Non-sensitizer IV

Table A.2.2 Acute Toxicity Profile for Aminocyclopyrachlor-methyl technical

Guideline No. Study Type MRID(s) Results Toxicity Category

870.1100 Acute oral [rat] 47560027 LD 50 >5000 mg/kg IV

870.1200 Acute dermal [rat] 47560028 LD 50 >5000 mg/kg IV

870.1300 Acute inhalation [rat] 47560029 LD 50 >5.4 mg/L IV

870.2400 Acute eye irritation [White New Zealand rabbit] 47560030 Mild irritant III

870.2500 Acute dermal irritation [rabbit] 47560031 Non-irritant IV

870.2600 Skin sensitization [Guinea Pig] 47560032 Non-sensitizer IV

Table A.2.3 Subchronic, Chronic and Other T oxicity Profile Toxicity Profile for Aminocyclopyrachlor

Guideline No Study Type MRID
Classification

Doses Results

870.3100 90-Day Oral Toxicity Feeding-mouse 47560010 (2008) 47560011 (2008) Acceptable/guideline

0, 300, 1000, 3000, 7000 ppm 0/0, 47/61, 154/230, 459/649, and 1088/1623 mg/kg/day (M/F) NOAEL= 7000 ppm (1088/1623 mg/kg/day M/F, limit dose)

LOAEL = not established.

870.3100 90-Day Oral Toxicity Feeding-rat 47573403 (2008) 47560007 (2008) Acceptable/guideline 0, 600, 2000, 6000, 18000 ppm 0/0, 34.8/44.8, 114.3/145.7, 349.4/448.0, NOAEL = 6000 ppm (349.4/448.0 mg/kg/day M/F)

LOAEL = 18,000 ppm (1044.6/1424.9 mg/kg/day M/F), based on decreased body weights, body weight gains, food consumption, and food effi ciency in both sexes.Page 45 of 76 1044.6/1424.9 mg/kg/day (M/F)

870.3150

90-Day Oral Toxicity Feeding-dog 47560012 (2008) 47560013 (2008) Unacceptable/guideline

0, 250, 1250, 5000, 15000 ppm

0/0, 6.5/7.0, 33/38, 126/124, 426/388 mg/kg /day M/F NOAEL = 15,000 ppm (426/388 mg/kg/day M/F)

LOAEL = not established.

870.3200 28-Day Dermal Toxicity- rat 47560014 (2008) Acceptable/guideline

0, 150, 400, or 1000 mg/kg/day NOAEL = 1000 mg/kg/day

LOAEL = not established.

870.3250 90-Day Dermal Toxicity- rat 47725701 (2009) Waived Memo D364756 (2009)

870.3465 90-Day Inhalation No study available. Waived Memo D373897 (2010)

870.3700a
Prenatal Developmental- rat 47560016 (2008) Acceptable/guideline

0, 30, 100, 300, or 1000 mg/kg/day (GD 6-20) Maternal NOAEL = 1000 mg/kg/day
LOAEL = not established. Developmental NOAEL= 1000 mg/kg/day
LOAEL = not established.

870.3700b
PrenatalDevelopmentalrabbit 47560015 (2008) Acceptable/guideline

0, 100, 300, 500, or 1000 mg/kg/day (GD 7-28) Maternal NOAEL = 500 mg/kg/day LOAEL = 1000 mg/kg/day based on mortality and abortion and decreased body weight gains and food consumption. Developmental NOAEL = 1000 mg/kg/day
LOAEL =not established.

870.3800 Reproduction and Fertility Effects-rat 47575101 (2008) Acceptable/guideline

0, 500, 1500, 5000, or 17,000 ppm

0/0, 36/41, 109/125, 363/416, or 1285/1454 mg/kg/day M/F Parental Systemic NOAEL = 5000 ppm (363/416 mg/kg/day M/F) Parental Systemic LOAEL = 17000 ppm (1285/1454 mg/kg/day) based on decreased body weights. Reproduction NOAEL = 17000 ppm (1285/1454 mg/kg/day M/F) Reproduction
LOAEL was not established. Offspring NOAEL = 5000 ppm (363/416 mg/kg/day) Offspring LOAEL = 17,000 ppm (1285/1454 mg/kg/day M/F) based on decreased body weights in F1 and F2 pups.

870.4100aChronic Toxicityrodent No study available Waiver recommended Memo D373897 (2010)

870.4100bChronic Toxicitynonrodent No study available Waiver recommended Memo D373897 (2010)

870.4200a Waiver recommendedPage 46 of 76 Oncogenicity-rat No study available Memo D373897 (2010)

Waiver recommended Memo D373897 (2010)

870.4200a Oncogenicity-mouse No study available Waiver recommended Memo D373897 (2010)

Gene Mutation

870.5100

In vitro Bacterial Gene
Mutation 47560019 (2007) Acceptable/guideline 0, 50, 150, 500, 1500, or 5000 μg/plate (+/- S9) There was no evidence of indu ced mutant colonies over background in the presence or absence of S9-activation.

Gene Mutation

870.5300

In vitro Mammalian
Cells Gene Mutation (Chinese Hamster Ovary Cells) 47560020 (2007) Acceptable/guideline 0, 750, 1000, 1500, 1750, or 2150 μg/mL (+/-S9) There was no evidence of indu ced mutant colonies over background in the presence or absence of S9-activation.

Cytogenetics

870.5375

In vitro Mammalian Cytogenetics
ChromosomalAberration Assayhuman peripheral blood lymphocytes 47560021 (2007) Acceptable/guideline 0, 267, 534, 1068, or 2136 μg/mL (+/-S9) There was no evidence of chro mosome aberrations induced over background in the presence or absence of S9-activation.

Cytogenetics

870.5385
Mammalian Bone
Marrow Chromosome
Aberration Test No study available Waived Memo D364576 (2009)

Cytogenetics-other

870.5395 In Vivo
Mammalian Cytogenetics - Erythrocyte
Micronucleus-mouse 47560022 (2007) 0, 500, 1000, or 2000 mg/kg (limit dose) No significant increase in th e frequency of micronucleated polychromatic erythrocytes in bone marrow after any
treatment time.

870.6100a Acute Delayed Neurotox-hen No study available Waiver recommended Memo D373897 (2010) 870.6100b 90-Day
Neurotox.-hen No study available Waiver recommended Memo D373897 (2010)

870.6200a Acute Neurotoxicity-rat 47725702 (2009) Acceptable/guideline 0, 200, 1000, 2000 mg/kg (limit dose)

(0.5%carboxymethylcellulose vehicle) NOAEL = 2000 mg/kg (limit dose)

No acute neurotoxicity.

870.6200b
Subchronic Neurotoxicity-rat 47573403 (2008) 47560007 (2008) Acceptable/guideline 0, 600, 2000, 6000, 18000 ppm 0/0, 34.8/44.8, 114.3/145.7, 349.4/448.0, NOAEL = 18,000 ppm (limit dose) (1044.6/1424.9 mg/kg/day M/F)

No subchronic neurotoxicity.Page 47 of 76 1044.6/1424.9 mg/kg/day (M/F)

870.7485
Metabolism and
Pharmacokinetics-rat 47560023 (2007) Acceptable/guideline 25 or 500 mg/kg bw (single oral dose) Peak plasma and RBC concentrations at 0.3-1.0 h. AUC
scaled with dose. Whole blood radiolabel distribution: plasma (60%), RBCs (40%) in RBCs. Plasma elimination half-life was 5.6-5.7 h. Majority eliminated within 24 h as unmetabolized parent: 35.8-53.71% (urine) 31.4-48.0% (feces). No sex differences.

870.7600 Dermal penetration No study available Waiver recommended Memo D373897 (2010)

870.7800 Immunotoxicity-rat 47560025 (2008)\ Acceptable/guideline 0, 600, 6000, 18000 ppm (male rats) 0, 42, 407, 1277 mg/kg/day (male rats) Systemic NOAEL= 18,000 ppm (1277 mg/kg/day) Systemic LOAEL= not established Immunotoxicity NOAEL= 18,000 ppm (1277 mg/kg/day) Immunotoxicity LOAEL= not established

870.7800 Immunotoxicity-mouse 47560026 (2008) Acceptable/guideline 0, 300, 3000, 7000 ppm (male mice) 0, 45, 425, and 1056 mg/kg/day (male mice Systemic NOAEL= 7,000 ppm (1056 mg/kg/day) Systemic LOAEL= not established Immunotoxicity NOAEL= 7,000 ppm (1056 mg/kg/day) Immunotoxicity LOAEL= not established

Table A.2.4 Subchronic, Chronic and Other T oxicity Profile Toxicity Profile for Aminocyclopyrachlor-methyl

Guideline No Study Type MRID
Classification

Doses Results

Non-guideline, OECD
415 –Extended One Gen. Repro.-rat 47560018 (2006)Acceptable/nonguideline 0, 600, 5000, 17000

ppm 0/0, 49/53, 385/435,
1378/1489 mg/kg/day M/F (28 d premating to PND 60 of F1). Parental Systemic NOAEL = 5000 ppm (398/435 mg/kg/day M/F) Parental Systemic LOAEL = 17,000 ppm (1378/1489 mg/kg/day) based on decreased food consumption and efficiency in the P generation and on decreased body weights and food consumption in the F1 generation. .

No reproductive toxicity (NOAEL=17,000 ppm (1378/1489 mg/kg/day).

Offspring NOAEL = 5000 ppm (398/435 mg/kg/day M/F) Offspring LOAEL = 17,000 ppm (1378/1489 mg/kg/day M/F) based on dehydration, decreased pup body weight gains, and decreased body weights late in lactation.

870.3100 90-Day Oral Toxicity Feeding-rat 47560008 (2008) 47560009 (2008) Acceptable/guideline 0, 600, 2000, 6000, 18000 ppm 0/0, 35/43, 117/133, 347/405, 1022/1219 mg/kg/day (M/F) NOAEL = 6000 ppm (347/405 mg/kg/day M/F)

LOAEL = 18,000 ppm (1022/1219 mg/kg/day M/F) based on decreased body weights, body weight gains, food consumption, and food effi ciency in both sexes.

Gene Mutation

870.5100

In vitro Bacterial Gene 47560033 (2005)Acceptable/Nonguideline There was no evidence of indu ced mutant colonies over background in the presence or absence of S9-activation.Page 48 of 76 Mutation 0, 100, 333, 1000, 3333, or 5000 μg/plate (+/-S9)

870.6300 Developmental Neurotoxicity-rat No study available Waiver recommended Memo D373897 (2010)

870.7200 Companion animal safety No study available Waiver recommended Memo D373897 (2010)

870.7485
Metabolism and
Pharmacokinetics-rat 47560024 (2007) Acceptable/guideline 25 or 500 mg/kg bw (single oral dose) Peak plasma and RBC concentrations at 0.3-0.6 h. AUC
scaled with dose. Whole blood radiolabel distribution: plasma (60%), RBCs (40%) in RBCs. Plasma elimination half-life was 8.7-13.3 h. Major ity eliminated within 24 h as DPX-MAT28: 78.80-78.82% (u rine), minor in feces (1.72- 4.57%). No sex differences.

A.3 Executive Summaries

A.3.1 Subchronic Toxicity

870.3100 90-Day Oral Toxicity - Rat

EXECUTIVE SUMMARY : In a subchronic oral and neurotoxicity study (MRID 47573403 and 47560007), aminocyclopyrachlor (DPX-MAT 28; 92.2% a.i.; Batch No. DPX-MAT28- 009) was administered in the di et to Crl:CD(SD) rats (15/sex/ dose) at doses (adjusted for purity) of 0, 600, 2000, 6000, or 18,000 ppm (equivalent to 34.8/44.8, 114.3/145.7, 349.4/448.0, and 1044.6/1424.9 mg/kg/day) for 13 w eeks (94-95 days in males and 96-97 days in females). Neurobehavioral assessment (functional observati onal battery [FOB] and motor activity testing) was performed prior to treatment and during Weeks 4, 8, and 13 on 10 rats/sex/group. On Day 56, plasma concentrat ions of DPX-MAT28 and the environmental degradateIN-LXT69 were measured in 5 rats/s ex/dose. At study termination, gross and histopathology were performed on 10 rats /sex/group, while 5 rats/sex/group were anesthetized and perfused in situ for neuropathological examinat ion. The tissues from the perfused animals in the control and 18,000 ppm groups were subjected to histopathological evaluation of brain, spinal cord, and peripheral nervous system tissues.

All animals survived to the day of scheduled sacrifice. One control male and one 6000 ppm female were accidentally killed during bl ood collection just prior to necropsy.

No treatment-related effects were observed in da ily or weekly clinical observations and there
were no test substance-relate d opthamological signs for either sex. There were no test substance-related or statistically significant effects on functional obser vational battery (FOB) parameters: forelimb and hindlimb grip strengt h, footsplay, body temperat ure, or behavioral parameters in either sex. Additionally, there we re no test substance-related or statistically significant effects on duration of movement or number of movements measured in the motor activity analysis of males and females.

At 18,000 ppm, decreases (p ≤ 0.05; except as noted) in body we ights were observed in the males from Days 28-91 ( ↓ 6-9%, NS at Days 56 and 70) and in the females on Days 56, 70, and 77 ( ↓ 8-10%). Overall (Days 0-91) body weight gain was decreased (p ≤ 0.05) by 15-18%Page 49 of 76 in both sexes. Significant decreases (p ≤ 0.05) in food consumption were observed at 18,000 ppm during Days 0-7, 21-28, and 42-49 in males ( ↓ 7-8%) and during Days 70-77 in females ( ↓ 11%). Decreased (p ≤ 0.05) food efficiency was noted in males during Days 21-28, 70-77, and 77-84 ( ↓ 18-73%) and in females during Days 62-70 ( ↓ 112%). Overall (Days 0-91) food efficiency was decreased (p ≤ 0.05) by 11% in males and 17% in females.

There were no adverse effects of the test substance on organ weights, ophthalmology, hematology, coagulation, clinical chemistry, or urinalysis parameters in males and females.
There were no effects of the test substan ce on brain weights or gross or microscopic neuropathology in either sex at any dose.

The plasma concentrations of DPX-MAT28 a nd the metabolite IN-LXT69 were measured on Day 56 by high performance liquid chromat ography with detection by tandem mass spectrometry (LC/MS/MS, MRID 47560007). DPX-MAT28 was the most abundant metabolite in male and female rats, with the highest concentrations at 10, 268 and 13, 428 ng/mL for 18,000 ppm male and female rats, respect ively. In contrast, plasma levels of INLXT68 were lower for this dose group at con centrations of 82 and 80 ng/mL for males and females, respectively. The average concentra tion of DPX-MAT28 in plasma was higher in
females than in males at all dose levels. Th e IN-LXT69 plasma concentrations were below the limit of quantitation for the 600 ppm di etary concentration. The average IN-LXT69 plasma concentrations appeared to be similar for males and females. There was no apparent plateau for the DPX-MAT28 of IN-LXT68 plasma concentrations when compared to dietary intake levels (e.g. plasma concentrations increase d with increasing concentration in the diet).

The LOAEL for systemic effects is 18,000 ppm (1044.6/1424.9 mg/kg/day), based on decreased body weights, body weight gains, fo od consumption, and food efficiency in
both sexes. The NOAEL is 6000 ppm (349.4/448.0 mg/kg/day).

The LOAEL for neurotoxicity was not observed. The NOAEL is 18,000 ppm (1044.6/1424.9 mg/kg/day) in both sexes.

The study is classified as Acceptable/Guideline and satisfies the guideline requirements for a 90-day oral toxicity study (OPPTS 870.3100; OE CD 408) and a subchronic neurotoxicity study (OPPTS 870.6200b; OECD 424) in rats.

. COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.

EXECUTIVE SUMMARY : In a subchronic oral t oxicity study (MRIDs 47560008 and 47560009), Aminocyclopyrachlor-methyl (95% a.i. ; Lot #068) was administered to 10 Sprague-Dawley rats/sex/dose group in th e diet at dose levels of 0, 600, 2000, 6000, or 18,000 ppm (equivalent to 0/0, 35/43, 117/133, 347/405, and 1022/1219 mg/kg/day in males/females) for approximately 90 days (94 or 95 days in males and 95 or 96 days in females). On Days 60 and 87, blood was collected from the orbital sinus or tail vein of 5 rats/sex/dose group for the dete rmination of plasma concentr ation of the test substance (methyl aminocyclopyrachlor) and the meta bolites DPX-MAT28 (aminocyclopyrachlor) and

IN-LXT69.Page 50 of 76 All animals survived to scheduled sacrifice. There were no treatment-related clinical signs or effects on ophthalmology. Functional Observat ional Battery (FOB) parameters were measured in a different study (MIRD 47560018) . At 18,000 ppm, body weight decreased with time and was decreased ( ↓ 8% ) in males and females by Day 91, although this decrease was not statistically significant. Statistically significant (p<0 .05) decreases in body weight were observed in females at earlier time point s (Day 42 and Day 84). Body weight gain also decreased with time, and was significantly decr eased over the treatment period (Day 0-91) in males ( ↓ 14%) and females ( ↓ 24%). Food consumption also tende d to decrease with time and was significantly decreased in males ( ↓ 9%) and females ( ↓ 11%) over the treatment period (Day 0-Day 91). Food efficiency was significantly decreased in females ( ↓ 31%) from Days 0-7. Food efficiency over the treatment pe riod (Days 0-91) was decreased in males ( ↓ 5%) and females ( ↓ 15%), but these decreases were not statistically significant.

There were no adverse effects of treatment on hematology, clinical chemistry, or urinalysis
parameters.

There were decreases in organ weights that we re not considered adve rse due to lack of corroborating gross and histopathol ogical changes. Absolute and relative (to brain weight) liver weights were decreased in the 18,000 ppm males ( ↓ 13%) and absolute, relative (to brain weight), and relative (to body wei ght) heart weights in the 6000 and 18,000 ppm females were decreased ( ↓ 8-16%).

The parent compound DPX-KJM44 (aminocyclopyr achlor methyl) was not detected in any of the plasma samples. DPX-MAT28 was th e predominant plasma metabolite. This metabolite was dose-dependently increased in all treated groups, with plasma concentrations of 254, 1489, 6444, and 20,660 ng/mL in the males and 376, 2202, 5316, and 29,784 ng/mL in the females fed the 600, 2000, 6000, and 18,000 ppm diets respectively. Plasma
concentrations of the metabolite IN-LXT69 we re considerably lower than DPX-MAT28, but were also dose-dependently incr eased in all treated groups, with plasma concentrations of 12, 45, 136, and 439 ng/mL in the males and 15, 45, 125, and 415 ng/mL in the females fed the 600, 2000, 6000, and 18,000 ppm diets respectively. All of the control plasma samples were below the limit of quantitation (LOQ) for DPX-KJM44 and IN-LXT69. Plasma concentrations for DPX-MAT28 were below the LOQ in all of the control samples for the males and in two of the samples from the females; however, 3 of the 5 female plasma samples had DPX-MAT28 at concentr ations 2 to 4 times the LOQ.

The LOAEL is 18,000 ppm (equivalent to 1022/ 1219 mg/kg/day in males/females) based on decreased body weights, body weight gains, food consumption, and food efficiency in both sexes. The NOAEL is 6000 ppm (equivalent to 347/405 mg/kg/day in males/females).

This study is classified as Acceptable/Guideline and satisfies the guideline requirements (OPPTS 870.3100a; OECD 408) for a subchr onic oral toxicity study in rats.

COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.Page 51 of 76 870.3150 90-Day Oral Toxicity – Dog

EXECUTIVE SUMMARY : In this subchronic oral toxi city study (MRID 47560012), 4 beagle dogs/sex/group were administered aminocycl opyrachlor (DPX-MAT28; 92.2% a.i.; Batch No. DPX-MAT28-009) daily via the diet (400 g offered daily for approxi mately 2 hours) at doses of 0, 250, 1250, 5000, or 15,000 ppm (equivalent to 0/0, 6.5/7.0, 33/38, 126/124, and 426/388 mg/kg/day in males/females) for 13 weeks.

No treatment related effect was observed on mort ality, clinical signs, ne urological evaluations, body weight, body weight gains, food consump tion, food efficiency, hematology, clinical chemistry, urinalysis, organ weights, or gross or mi croscopic pathology.

A dose-related increase in the incidence of skin s caling on the feet was observed in males, with 4/4 males affected at 15,000 ppm. Half of the fe males were affected at the high dose. In most cases, all 4 feet exhibited scaling. The time of onset of scaling in most cases was 41-56 days, continuing to study termination (Day 91). The clinical severity of this effect was not noted and the foot pads were not biopsied. This effect was not considered adverse, because no impairment in walking or weight bearing and no grooming (e.g. licking/biting) of the feet was observed.

The plasma concentrations of parent increa sed with dietary inta ke ranging from 1968-63,000 ng/mL in males and 3193-82,575 ng/mL in fema les at doses of 250-15,000 ppm. Plasma concentrations were always higher in the female s than in the males. The metabolite IN-LXT69 was below the limit of quantitation except at 15,000 ppm, where only minor amounts (11.6-11.7 ng/mL) were noted (MRID 47560013).

Total cytochrome P450 measur ed was unrelated to dose in both sexes and was 0.320-0.409 nmol/mg in males and 0.378-0.421 nmol/mg in females. At 5000 and 15,000 ppm, induction of the isozymes 1A1 in males ( ↑ 402-420%) and 2B1/2 in males ( ↑ 91-125%) and females ( ↑ 34- 93%) was observed (p ≤ 0.05 at 5000 ppm only). A decreased level of 2E1 was noted in the 15,000 ppm males ( ↓ 37%). Although the effect on 2E1 seemed dose-dependent, the noted decrease was not statistically si gnificant and a similar effect was not noted in females. It is
unclear if there is an in hibitory effect on 2E1.

The LOAEL was not observed. The NOAEL is 15,000 ppm (equivalent to 426/388 mg/kg/day in males/females).

This study is classified Unacceptable/Guideline and does not satisfy the guideline requirements (OPPTS 870.3150; OECD 409) for a s ubchronic oral toxicity study in dogs. An adverse effect
was not noted and the limit dose wa s not tested. This study is upgradable pending submission of a satisfactory dose- selection rationale.

COMPLIANCE : Signed and dated Data Confidentiality, GLP Compliance, Flagging, and Quality Assurance statements were provided.Page 52 of 76 870.3200 21/28-Day Dermal Toxicity – Rat

EXECUTIVE SUMMARY : In a 28-day dermal toxicity study (MRID 47560014), DPXMAT28 (Aminocyclopyrachlor; 90.9% a.i., Ba tch # DPX-MAT28-010) was applied to the shaved intact skin of 10 Sprague-Dawley rats/sex/ dose at dose levels (adj usted for purity) of 0, 150, 400, or 1000 mg/kg/day (limit dose) for 6 hours/day for 28 consecutive days.

There were no unscheduled deaths. There were no effects of the test substance on ophthalmology parameters. The only clinical sign observed was limited and very slight (barely perceptible) erythema/edema (score of 1 on a scale of 4, 4 being severe) in three males. Animals affected were one male at 400 mg/kg/day on Day 28, one male at 1000 mg/kg/day on Day 3, and one male at 1000 mg/kg/day on Day 28. There were no adverse effects of the test substance on body weight, body weight gain, food consumpti on, food efficiency, clinical chemistry, hematology, gross pathology, or histopathology.

There were statistically significan t, dose-related changes in adre nal gland and ovary weights in 1000 mg/kg/day females and a decrease in kidney weights in females at 150 mg/kg/day that were not considered adverse due to a lack of corroborating microscopic lesions.

The LOAEL was not observed. The NO AEL is 1000 mg/kg/day (limit dose).

This study is classified as Acceptable/Guideline and satisfies the guideline requirement for a 28-day dermal toxicity study (O PPTS 870.3200; OECD 410) in rats.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

870.3250 90-Day Dermal Toxicity – Rat

No study was submitted. This study was waived in a Memorandum entitled “Waiver request for a 90-day dermal toxicity study ( 870.3250) and status of the mutage nicity testing database for DPX-MAT28”, J. Ryman, May 13, 2009, D364576.

870.3465 90-Day Inhalation – Rat

No study was submitted. This study was recommende d for a waiver in a Memorandum entitled “Recommended waivers of conditionally require d toxicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because significant inhalation exposure is not anticipated for the proposed us e patterns due to low volatility, outdoor uses, application methods that are not anticipated to generate respirab le aerosols, and high margins of

exposure.Page 53 of 76 A.3.2 Prenatal Developmental Toxicity

870.3700a Prenatal Developmental Toxicity Study – Rat

EXECUTIVE SUMMARY : In a developmental toxicity study (MRID 47560016), Aminocyclopyrachlor (92.2%; Batch #DPX-MAT 28-9-009) in 0.5% methylcellulose was administered via daily oral gavage in a dos e volume of 5 mL/kg to 25 time-mated presumed pregnant Sprague-Dawley rats/dose group at doses of 0, 30, 100, 300, or 1000 mg/kg/day from gestation days (GD) 6-20. On GD 21, all matern al rats were euthanized; each dam’s uterus was
removed via cesarean section and its contents examined. The fetuses were examined for external, visceral, and skeletal malformations and variations.

All maternal animals survived until scheduled term ination. No clinical signs of toxicity were noted in any of the dams. Body weights, body wei ght gains, and food consumption in the treated groups were comparable to controls throughout the study. The only gross abnormality was liver discoloration in a single dam at 100 mg/kg/day, and this findi ng was considered incidental because it was minimal in incidence and not observed at the high dose.

The maternal LOAEL was not observed. Th e maternal NOAEL is 1000 mg/kg/day (limit dose).

There were no abortions, premature deliveries, late resorptions, complete litter resorptions, or
dead fetuses. There were no effects of treatment on the numbers of litters, live fetuses, or early resorptions. Furthermore, sex ratio and post-implantation losse s in the treated groups were comparable to controls.

There was no evidence of altered growth or development. Fetal body weights in the treated groups were comparable to controls.

There were no treatment-related external, visceral , or skeletal variations or malformations. Skeletal variations in the skull, vertebrae, ribs, and sternebrae were unrelated to dose. One skeletal malformation (fused cervical vertebra e) was found at 300 mg/kg/day. The only other malformations were: anophthalmia and eye bulge in one 300 mg/kg/day fetus and protruding tongue in another 300 mg/kg/day fetus. These findi ngs were considered incidental because they only occurred in individual fetuses an d were not observed at the high dose.

The developmental LOAEL was not observ ed. The developmental NOAEL is 1000 mg/kg/day (limit dose).

This study is classified as Acceptable/Guideline and satisfies the guideline requirement (OPPTS 870.3700a; OECD 414) for a developmen tal toxicity study in rats.

COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.Page 54 of 76 870.3700b Prenatal Developmenta l Toxicity Study - Rabbit

EXECUTIVE SUMMARY : In a developmental toxicity study (MRID 47560015), Aminocyclopyrachlor (92.2% a.i.; Lot #MAT28-009) in 0.5% methylcellulose was administered daily via oral gavage in a dose volume of 4 mL/kg to 22 time-mated presumed pregnant New Zealand White rabbits/dose group at doses of 0, 100, 300, 500, or 1000 mg/kg/day from gestation days (GD) 7-28. On GD 29, all matern al rabbits were euthanized; each dam’s uterus
was removed via cesarean section and its contents examined. The fetuses were examined for external, visceral, and skeletal malformations and variations.

There was one maternal death at 1000 mg/kg/ day on GD 13 that was considered treatmentrelated. Increased respiration was observed 1 hour afte r dosing on GD 7 in this animal, and rales and decreased defecation were noted during GD 9-13. This female had a body weight loss of 394 g from GD 7-13 and consumed ≤ 14 g food/day for 4-5 days prior to death. Also at 1000 mg/kg/day, two animals aborted (one on GD 20 and the other on GD 26). Clinical findings
noted for both females included decreased defeca tion several days prior to abortion and red material in the cage pan or angiogenital area on the day of abortion. These abortions may be secondary to body weight loss >10%. These fe males exhibited body weight losses of 636-643 g (17-19%) from GD 7 through the day of abortion. These maternal effects corresponded with reduced food consumption, generally ≤ 17 g/day from GD 13 or 17 th rough the day of abortion.

There was one death at 1000 mg/kg/day unrelated to treatment that was attributed to a gavage
error and another death at 100 mg/kg/day of unknown cause. One 300 mg/kg/day animal aborted on GD 28. Clinical findings noted for this female prior to abortion incl uded 11 occurrences of
decreased defecation and 3 occurrences of soft stool. This female consumed ≤ 18 g of food per day between GD 18-19 and 27-28, but had no notable effects on body weight gain. This abortion at 300 mg/kg/day was not considered an effect of treatment because it was not dose-related (no abortions at 500 mg/kg/day). Aside from the a bove-mentioned clinical signs associated with mortality and abortion, no treatment-related clin ical signs were observed. The only treatmentrelated gross findings at necropsy were in animals that died or aborted. These findings included red skin matting around the urogenital or nasal areas , dark red contents in the vagina, and white precipitate in the abdominal soft tissue.

Reductions in food consumption were statistical ly significant only in the 1000 mg/kg/day group.
These reductions were consiste ntly about 30% after GD 14-15 through the end of the study. Decreases in body weight gain were statistically significant only at GD 14-17, although the decreases throughout the remainder of the study ar e probably of biological significance. This consistent relationship between decreased f ood consumption and decreased body weight gain were not observed in the 500 mg /kg/day group. In this group, no significant differences in body weight gain were observed and there were no significant decreases in food consumption.

The maternal LOAEL is 1000 mg/kg/day (limit dose) based on mortality, decreased body weight gains and food consumption, a nd abortion. The maternal NOAEL is 500 mg/kg/day.

At 1000 mg/kg/day, there were two animals that we re not pregnant, two th at died, and two that aborted, resulting in a lower number of litters at this dose (16) compared to controls (21). WhenPage 55 of 76 examined on a per litter basis, there were no effects of treatment on the mean numbers live fetuses, early resorptions, or late resorptions. Furthermore, fetal body weights, sex ratio, and post-implantation losses in the treated groups were comparable to controls.

There were no treatment-related external, viscer al, or skeletal malformations or variations.

The developmental LOAEL was not observ ed. The developmental NOAEL is 1000 mg/kg/day (limit dose).

This study is classified Acceptable/Guideline and satisfies the guideline requirement (OPPTS 870.3700b; OECD 414) for a developmen tal toxicity study in rabbits.

COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.

A.3.3 Reproductive Toxicity

870.3800 Reproduction and Fertility Effects – Rat

EXECUTIVE SUMMARY : In a two-generation repr oduction toxicity study (MRID 47575101), DPX-MAT28 (Aminocyclopyrachlor; 90.9-92.2% a.i.; Batch Nos. DPX-MAT28- 009 and DPX-MAT28-010) was administered in the diet to 28 Sprague Dawley (Crl:CD[SD]) rats/sex/dose group at dietar y levels of 0, 500, 1500, 5000, or 17,000 ppm (equivalent to 0/0, 36/41, 109/125, 363/416, and 1285/1454 mg/kg bw/day in males/females during pre-mating) for two successive generations with one litter per generation. The P (parental) generation animals were fed the test diets for at least ten weeks pr ior to mating to produce the F1 litters. The F1 litters were culled on post-natal day (PND) 4 to eight pups/litter (four/sex where possible). On PND 21, one pup/sex/litter (where po ssible) was selected and fed the same test diet concentration
as the dam. These animals were fed the test di ets for at least ten weeks prior to mating (at 13 weeks of age) to produce the F2 litters.

No treatment-related effects were observed on mortality, clinical signs , or macroscopic or microscopic findings.

Over the pre-mating period in P and F1 males, body weights were significantly (p ≤ 0.05) decreased ( ↓ 6-15%) at 5000 ppm and above, as were body weight gains ( ↓ 7-17%). Food efficiency was decreased ( ↓ 8-15%) at 1500 ppm and above. For P and F1 females over this period, body weights were decreased ( ↓ 6-14%) at 17,000 ppm. Food efficiency and body weight gain were decreased for P females only at 17,000 ppm ( ↓ 12-16%).

Over the period of gestation in P and F1 females, body weight and body weight gain was significantly decreased for P females only at 17,000 ppm ( ↓ 8-12%). Food consumption and food efficiency were also decreased for these animals ( ↓ 10% and ↓ 20%, respectively). There were no significant effects of the test substance on these parameters in F1 females. Over the lactation period, body weights were transiently but significantly decreased ( ↓ 7-9%) in P females at 17,000 ppm on LD 0-7. Decreases in body weights of F1 females were not statistically significant.Page 56 of 76 Terminal body weights were significantly (p ≤ 0.05) decreased at 17,000 ppm for P males and females ( ↓ 6-7%) F1 males ( ↓ 16%). At 5,000 ppm, terminal body weight was decreased ( ↓ 9%) for F1 males only. There were significant decreases ( ↓ 4-5%) in absolute (but not relative) brain weights for P and F1 females at 17,000 ppm. At 5,000 ppm, decreases in absolute brain weights were observed for P females only ( ↓ 4%). There were no correlating microscopic findings.

The LOAEL for parental toxicity is 17, 000 ppm (equivalent to 1285/1454 mg/kg in males/females), based on decreased body weig hts in parental males and females. The NOAEL is 5000 ppm (equivalent to 363/416 mg/kg in males/females).

No treatment-related effects on litter parameters were noted for the F1 or F2 generations. Specifically, there were no treatmen t-related effects on survival indi ces, clinical signs, sex ratio, attainment of developmental landmarks , or gross or microscopic pathology.

At 17,000 ppm, body weights were significantly (p ≤ 0.05) decreased at PND 21 in the F1 ( ↓ 15%) and F2 pups ( ↓ 8%). Body weights in the F1 pups were consistently decreased at PND 0, 4, 7, 14, and 21 at this dose, whereas body weights were decreased in F2 pups only at PND 21. There were no statistically significant decreases in body weight gain . In weanlings, terminal body weights were significantly decreased in both gene rations for both sexes (F1 males, F1 females, F2 males, F2 females) at 17,000 ppm ( ↓ 9-14%).

The LOAEL for offspring toxicity is 17,000 ppm (equivalent to 1285/1454 mg/kg in males/females), based on decreased body weights in the F1 and F2 pups. The NOAEL is 5000 ppm (equivalent to 363/416 mg /kg in males/females).

No treatment-related differences were observed in estrus cycle length or cyclicity, sperm parameters, numbers of primordial and pre-antral follicles, mati ng, fertility, pre- coital interval length, gestation length, number of implantation sites, or post-im plantation loss, or reproductive failures. Thus reproductive performance of P a nd F1 animals was not affected by treatment.

The LOAEL for reproductive toxicity was not observed. The NOAEL is 17,000 ppm (equivalent to 1285/1454 mg/k g in males/females).

This study is classified as Acceptable/Guideline and satisfies the guideline requirements (OPPTS 870.3800; OECD 416) for a two-generati on reproduction study in the rat.

COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.

A.3.4 Chronic Toxicity

870.4100a (870.4300) Chronic Toxicity – Rodent

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ry man, February 4, 2010, D373897).Page 57 of 76 870.4100b Chronic Toxicity -Nonrodent

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ry man, February 4, 2010, D373897).

A.3.5 Carcinogenicity

870.4200a Oncogenicity - rat

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because the proposed use patterns have low potential for chronic and signi ficant exposure. Also, no evidence of genotoxic
effects were observed in mutagenicity studies in vitro , and no pathological effects were observed
in oral subchronic studies.

870.4200b Oncogenicity - Mouse

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ry man, February 4, 2010, D373897).

A.3.6 Mutagenicity

870.5100 Bacterial Reverse Mutation

EXECUTIVE SUMMARY : In two independent trials of a reverse gene mutation assay in bacteria (MRID 47560019), Salmonella typhimurium strains TA98, TA100, TA1535, and
TA1537 and Escherichia coli strain WP2 uvrA were exposed to DPX-MAT28 (Aminocyclopyrachlor, 92.2% a.i., Batch No.: DPX-MAT 28-009) in DMSO at concentrations of 0, 1.5, 5.0, 15, 50, 150, 500, 1500, or 5000 μg/plate (+/-S9, Trial 1) and 0, 50, 150, 500, 1500, or 5000 μg/plate (+/-S9, Trial 2) using the standard plate incorporation met hod. The S9 fraction was derived from the livers of male Spra gue-Dawley rats induced with Aroclor ® 1254. Standard strain-specific mutagens served as positive controls.

DPX-MAT28 was tested up to the limit dose (5000 μg /plate). No evidence of cytotoxicity was observed at any concentration in any strain in either trial in the presence or absence of S9-
activation. There were no marked in creases in the mean number of revertants/plate in any strain. The positive controls induced the appropriate resp onse in all strains in th e presence and absence
of S9-activation. There was no evidence of induced mutant colonies over background.

The study is classified as Acceptable/Guideline and satisfies the guideline requirements (OPPTS 870.5100; OECD 471) for in vitro mutagenicity (bacterial re verse gene mutation) data.

COMPLIANCE : Signed and dated Data Confidentiality, GLP Compliance, and Quality Assurance statements were provided.Page 58 of 76 EXECUTIVE SUMMARY : In a reverse gene mutation a ssay in bacteria (MRID 47560033), Salmonella typhimurium strains TA98, TA100, TA1535, and TA1537 and Escherichia coli strain

WP2 uvr A were exposed to IN-KJM44 (aminocycl opyrachlor-methyl, 95.3% a.i., Batch No.: 032) in DMSO at concentrations of 0, 100, 333, 1000, 3333, or 5000 μg/plate (+/-S9) using the standard plate incorporation method. The S9 fraction was derived from the livers of male Sprague-Dawley rats induced with Aroclor ® 1254. Standard strain-specific mutagens served as positive controls.

IN-KJM44 was tested up to the limit dose (5000 μg /plate). No evidence of cytotoxicity was observed at any concentration in any strain in either trial in the presence or absence of S9-
activation. There were no marked in creases in the mean number of revertants/plate in any strain. The positive controls induced the appropriate resp onse in all strains in th e presence and absence
of S9-activation. There was no evidence of induced mu tant colonies over background.

The study is classified as Acceptable/Non-guideline and does not satisfy the guideline requirements (OPPTS 870.5100; OECD 471) for in vitro mutagenicity (bacterial reverse gene mutation) data. The study is upgradable to Acceptable, Guideline following receipt of GLP compliance and Quality Assurance statements.

COMPLIANCE : A signed and dated Data Confidential ity statement was provided. The study was conducted in a GLP-compliant lab following SO Ps but was not proven to be GLP compliant. A Quality Assurance statement was not provided.

870.5300 In Vitro Mammalian Cell Mutation

EXECUTIVE SUMMARY : In a mammalian cell gene mutation assay at the HGPRT locus (MRID 47560020), duplicate cultures of Chines e hamster ovary (CHO) cells cultured in vitro were exposed to DPX-MAT28 (Aminocyclopyrac hlor, 92.2% a.i., doses adjusted for purity, Batch No: DPX-MAT28-009) in DMSO at concentrations of 0, 750, 1000, 1500, 1750, or 2150 μg/mL in the presence and absence of S9-activation for 5 hours.

DPX-MAT28 was tested up to 2150 μg/mL, whic h was the solubility limit (4000 μg/mL +/-S9 was precipitating). No precipitation of the test material or evidence of cytotoxicity were observed at any concentration in the presence or absence of S9. No marked increase in mutant frequency was observed at any c oncentration in the presence or absence of S9-activation. The positive controls induced the appropriate response in the presence and absence of S9. There was
no evidence of induced mutant colonies over background in the presence or absence of S9-
activation.

This study is classified as Acceptable/Guideline and satisfies the guide line requirement (OPPTS 870.5300, OECD 476) for in vitro mutagenicity (mammalian fo rward gene mutation) data.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

870.5375 In Vitro Mammalian Chromosomal AberrationPage 59 of 76 EXECUTIVE SUMMARY : In a mammalian cell cytogenetic s assay (chromosome aberration; MRID 47560021), lymphocyte cultures were prepared from human peripher al blood and exposed to DPX-MAT28 (92.2% a.i., doses adjusted for purity, Batch # DPX-MAT28-009) in DMSO at concentrations of 0, 267, 534, 1068, or 2136 μg/mL for either 4 hours followed by a 16 hour recovery period (+/-S9) or for 20 hours with no recovery period (-S9). The S9 fraction was
derived from the livers of male rats indu ced with Aroclor 1254. Cyclophosphamide and mitomycin C served as the positive controls in the presence and absence of S9, respectively.

DPX-MAT28 was tested up to the limit dose (2136 μg /mL, 10mM). No precipitation of the test material was observed at any con centration (+/-S9). No substan tial decreases in mitotic index were observed at any concentra tion after 4 (+/-S9) or 20 hrs (-S 9) of treatment; therefore, concentrations of 0, 534, 1068, and 2136 μg/mL were selected for evaluation of chromosomal aberrations in each assay. No significant increases in the mean percentage of cells with
structural or numerical abortions or in aberrations per cell we re observed after treatment for 4 hrs (+/-S9) or 20 hrs (-S9). The positive controls induced the appropriate response in the presence
and absence of S9. There was no evidence of ch romosome aberrations induced over background in the presence or absence of S9-activation.

This study is classified as Acceptable/Guideline and satisfies the Guideline requirement (OPPTS 870.5375, OECD 473) for in vitro mutagenicity (chromosome aberration) data.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

870.5385 Mammalian In Vivo Bone Marrow Chromosomal

No study was submitted. This study was waived in a Memorandum entitled “Waiver request for a 90-day dermal toxicity study ( 870.3250) and status of the mutage nicity testing database for DPX-MAT28”, J. Ryman, May 13, 2009, D364576.

870.5395 Mammalian Erythrocyte Micronucleus

EXECUTIVE SUMMARY : In a bone marrow micronucleus assay (MRID 47560022), 5 young adult Crl:CD1(ICR) mice/sex/dose/sampling time were treated once via gavage (10 mL/kg) with DPX-MAT28 (Aminoc yclopyrachlor; 92.2% a.i., doses adjusted for purity; Batch No. DPX-MAT28-009) in sterile water at dos es of 0, 500, 1000, or 2000 mg/kg (limit dose).
Bone marrow cells were harvested at 24 a nd 48 hours post-dosing. Additionally, 5 mice/sex were treated with cyclophosphamide (50 mg/kg) and marrow cells were harvested at 24 hours post-dosing.

DPX-MAT28 was tested at up to the limit dose (2000 mg/kg). No mo rtality or clinical signs of toxicity were observed at any dos e at either time point. No si gnificant decrease in polychromatic erythrocyte to normochromatic er ythrocyte ratios (PCE:NCE) wa s observed, indicating that the
test material was not toxic to the bone marrow. The positive control induced the appropriate

response. There was no significant increase in the frequency of micronucleated polychromatic erythrocytes in bone marrow after any treatment time.Page 60 of 76 This study is classified as Acceptable/Guideline and satisfies the guide line requirement (OPPTS 870.5395; OECD 474) for in vivo cytogenetic mutagenicity data.

COMPLIANCE : Signed and dated Data Confidentiality, GLP Compliance, and Quality Assurance statements were provided.

A.3.7 Neurotoxicity

870.6100a Acute Delayed Neurotoxicity Study - Hen

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because aminocyclopyrachlor is not an organophosphate pesticide, nor was there ev idence of acute or subchronic neurotoxicity.

870.6100b 90-Day Neurotoxicity Study - Hen

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because aminocyclopyrachlor is not an organophosphate pesticide, nor was there ev idence of acute or subchronic neurotoxicity.

870.6200a Acute Neurotoxicity Screening Battery

In an acute neurotoxicity study (MRID 47725702), DPX-MAT28 (92.2% a.i.; Lot # 009) in 0.5% aqueous methylcellulose was administered once via gavage (5 mL/kg) to 10 Sprague-Dawley rats/sex/group at dose levels of 0, 200, 1000, or 2000 mg/kg (limit dose). Neurobehavioral assessment (functional observational battery [FOB ] and motor activity testing) was performed on all rats at pre-dosing and Days 1 (approximate ly 2 hours post-dosing; estimated time of peak effect), 8, and 15. At study termination, 5 ra ts/sex/group were anesthetized and perfused in situ for neuropathological examination. The tissues fr om the perfused animals in the control and 2000 mg/kg groups were subjected to histopathological evaluati on of brain and peripheral nervous system tissues. Acceptable positive control data were provided.

There were no treatment-related effects on morta lity, clinical signs of toxicity, body weight, food consumption, brain weight, body weight gain, gross pathology, or ne uropathology. FOB and motor activity testing revealed no treatment-related effects.

There were no neurological effects observed at any dose in either sex.

The LOAEL was not observed. The NOAEL is 2000 mg/kg (limit dose).

The study is classified as Acceptable/Guideline and satisfies the guide line requirement (OPPTS 870.6200a) for an acute neurotoxicity study in rats.COMPLIANCE : Signed and dated Data Confidentiality, GLP Compliance, Flagging, and Quality Assurance statements were provided.

870.6200b Subchronic Neurotoxicity Screening Battery

EXECUTIVE SUMMARY : In a subchronic oral and neurotoxicity study (MRID 47573403 and 47560007), aminocyclopyrachlor (DPX-MAT28; 92.2% a.i.; Batch No. DPX-MAT28-009) was administered in the diet to Crl:CD(SD) rats (15/sex/dose) at doses (a djusted for purity) of 0, 600, 2000, 6000, or 18,000 ppm (equivalent to 34.8/44.8, 114.3/145.7, 349.4/448.0, and 1044.6/1424.9 mg/kg/day) for 13 weeks (94-95 days in males and 96-97 days in females). Neurobehavioral assessment (func tional observational battery [FOB] and motor activity testing) was performed prior to treatment and during Weeks 4, 8, and 13 on 10 rats/sex/group. On Day 56, plasma concentrations of DPX-MAT28 and the metabolite IN-LXT69 were measured in 5/sex/dose. At study termination, gro ss and histopathology were performed on 10 rats/sex/group, while 5 ra ts/sex/group were anes thetized and perfused in situ for neuropathological examination. Th e tissues from the perfused animals in the control and 18,000 ppm groups were subjected to hi stopathological evaluation of brai n, spinal cord, and peripheral nervous system tissues.

All animals survived to the day of scheduled sacrifice. One control male and one 6000 ppm female were accidentally killed during bl ood collection just prior to necropsy.

No treatment-related effects were observed in da ily or weekly clinical observations and there were no test substance-related op thamological signs for either sex. There were no test substancerelated or statistically significant effects on f unctional observational battery (FOB) parameters: forelimb and hindlimb grip strength, footsplay, b ody temperature, or behavioral parameters in either sex. Additionally, there were no test substance-related or statistically significant effects on
duration of movement or number of movements measured in the mo tor activity analysis of males
and females.

At 18,000 ppm, decreases (p ≤ 0.05; except as noted) in body wei ghts were observed in the males from Days 28-91 ( ↓ 6-9%, NS at Days 56 and 70) and in the females on Days 56, 70, and 77 ( ↓ 8- 10%). Overall (Days 0-91) body weight gain was decreased (p ≤ 0.05) by 15-18% in both sexes. Significant decreases (p ≤ 0.05) in food consumption were observed at 18,000 ppm during Days 0-7, 21-28, and 42-49 in males ( ↓ 7-8%) and during Days 70-77 in females ( ↓ 11%). Decreased (p ≤ 0.05) food efficiency was noted in ma les during Days 21-28, 70-77, and 77-84 ( ↓ 18-73%) and in females during Days 62-70 ( ↓ 112%). Overall (Days 0-91) f ood efficiency was decreased (p ≤ 0.05) by 11% in males and 17% in females.

There were no adverse effects of the test substance on organ weights, ophthalmology, hematology, coagulation, clinical chemistry, or urinalysis parameters in males and females.
There were no effects of the test substan ce on brain weights or gross or microscopic neuropathology in either sex at any dose.

Page 61 of 76Page 62 of 76 The plasma concentrations of DPX-MAT28 a nd the metabolite IN-LXT69 were measured on Day 56 by high performance liquid chromatography with detection by tandem mass spectrometry (LC/MS/MS, MRID 47560007). DPX-MAT28 was the most abundant metabolite in male and female rats, with the highest concentrati ons at 10, 268 and 13, 428 ng/mL for 18,000 ppm male and female rats, respectively. In contrast, plas ma levels of IN-LXT68 were lower for this dose group at concentrations of 82 and 80 ng/mL for males and females, respectively. The average concentration of DPX-MAT28 in pl asma was higher in females than in males at all dose levels. The IN-LXT69 plasma concentrations were below the limit of quantitation for the 600 ppm dietary concentration. The average IN-LXT69 plasma concentrations appear ed to be similar for males and females. There was no apparent pl ateau for the DPX-MAT28 or IN-LXT68 plasma concentrations when compared to dietary intake levels (e.g. plasma c oncentrations increased with increasing concentra tion in the diet).

The LOAEL for systemic effects is 18,000 ppm (1044.6/1424.9 mg/kg/day), based on decreased body weights, body weight gains, food consumption, and food efficiency in both
sexes. The NOAEL is 6000 ppm (349.4/448.0 mg/kg/day).

The LOAEL for neurotoxicity was not observed. The NOAEL is 18,000 ppm (1044.6/1424.9 mg/kg/day) in both sexes.

The study is classified as Acceptable/Guideline and satisfies the guideline requirements for a 90-day oral toxicity study (OPPTS 870.3100; OECD 408) and a subchronic neurotoxicity study (OPPTS 870.6200b; OECD 424) in rats.

. COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.

870.6300 Developmental Neurotoxicity Study

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because there is no evidence of acute or subchronic neurotoxicity in adult animal s and no evidence of increased susceptibility in young animals.

870.7200 Companion Animal Safety

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because no uses on companion animals or companion animal exposures are expected.A.3.8 Metabolism

870.7485 Metabolism - Rat

EXECUTIVE SUMMARY In this metabolism study (MRID 47560023), [pyramidine-2- 14 C]- DPX-MAT28 (aminocyclopyrachlor; Lot No. 01; radiochemical purity 99.5%) in 0.5% methylcellulose (4 ml/kg) was administered by a si ngle oral gavage to groups of Sprague Dawley rats for the following studies: (i) a pilot mass balance study conducted on one rat/sex dosed at 25 mg/kg; (ii) a blood pharmacokinetic study conducted on four rats/sex give n either a 25 or 500 mg/kg dose; and (iii) a plasma metabolite study c onducted on three rats/sex dosed at 500 mg/kg. Metabolite profiles were also determined for urin e and feces collected in the pilot mass balance study.

DPX-MAT28 was absorbed with peak concentrations occurring in plasma and RBCs at 0.3-1.0 h post-dosing. The AUC for DPX-MAT28 was 7.0-9.0 μ g*h/g at 25 mg/kg and 150.8-168.4

μ g*h/g at 500 mg/kg, a difference of approximately 19 to 21-fold, which scaled with the 20-fold difference in dose. The majority of the whol e blood radiolabel was found in the plasma (60%), with about 40% in RBCs, Total recoveries of the administered dose (AD) were 69.9% for the male (which is low) and 107.9% for the female . DPX-MAT28 was rapidly eliminated after a single oral gavage dose, with mean elimination half-life values of 5.6-5.7 h for plasma at 25 or 500 mg/kg. The majority of radioactivity wa s recovered 0-24 h pos t-dosing, with 35.8-53.71%
eliminated in the urine of males and females a nd 31.4-48.0% eliminated in the feces of males and females No radioactivity was detected in the expired air as exhaled volatiles or CO 2 for DPXMAT28. Cage wash accounted for a small por tion (0.36-1.21% AD) of radioactivity, and a minor amount of radioactivity was detected in the residual feed. At 168 h post-dosing, the residual carcass of the male accounted for 0.04% AD; radioactivity was below the limit of
detection in the collected tissues from bot h sexes and in the female residual carcass.

Plasma, urine, and feces were examined for me tabolites at 30 minutes, 24 hours, and 24 hours, respectively. Only a single peak was obs erved in each matrix, and was identified as unmetabolized parent. In a concurrently review ed subchronic oral toxici ty study in rats (MRID 47573403), a metabolite (IN-LTX69) was quantified in plasma; however, this metabolite was not detected in the present study following a single dose of the test compound. Control pooled plasma samples and pre-dose urine and fecal sa mples were fortified with radiolabeled DPXMAT28 dosing solution to determine stability at 3 (feces), 10 (urine), and 14 (plasma) days; no
noticeable differences were observe d, indicating that the test co mpound was stable in the plasma, urine, and feces, and in the prepared sample extracts.

This metabolism study is classified Acceptable/Guideline and satisfies the guideline requirement for a Tier 1 metabolism study [OPPTS 870.7485, OECD 417] in rats.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

Page 63 of 76EXECUTIVE SUMMARY : In this metabolism study (MRID 47560024), [pyramidine-2- 14 C]- DPX-KJM44 (Lot No. SEL/1539A; radioche mical purity 99.2%) in 4 ml/kg of 0.5% methylcellulose was administered by a single oral gavage to groups of Sprague Dawley rats for the following studies: (i) a pilot mass balance study conducted on one rat/sex dosed at 25 mg/kg; (ii) a blood pharmacokinetic study conducted on four rats/sex gi ven either a 25 or 500 mg/kg dose; and (iii) a plasma metabolite study conducted on three rats/sex dosed at 500 mg/kg. Metabolite profiles were also determined for urin e and feces collected in the pilot mass balance study.

The test compound was rapidly absorbed with peak concentrations occurring in plasma and RBC at 0.3-0.6 h post-dosing. The AUC for DPX-KJM44 was 14.5-14.8 μ g*h/g at 25 mg/kg and

241.5-255.8 μ g*h/g at 500 mg/kg, a difference of approxi mately 18-fold, which scaled with the 20-fold difference in dose. The majority of th e whole blood radiolabel was found in the plasma (60%), with about 40% in RBCs. No differences were observed between the sexes.

Total recoveries of the admi nistered dose (AD) were 89.2% for the male and 82.6% for the female. The plasma half-life for DPX-KJM 44 was 8.7-13.3 h at 25 or 500 mg/kg . The majority of radioactivity was recovered in the urine by 24 h post-dosing. (78.80-78.82%) for
both males and females. A small amount was eliminated in the f eces (1.72-4.57%) within 24 hours. No radioactivity was detected in the expired air as exhaled volatiles or CO 2 during the first 48. Cage wash accounted for a small portio n (0.08-1.92% AD) of radioactivity, and a minor amount of radioactivity was detected in the re sidual feed. At 168 h pos t-dosing, radioactivity
was below the limit of detection in the collected ti ssues except for the male gastrointestinal tract and contents (0.01% AD). Minor amounts of radioactivity were al so detected in the residual carcass (0.12-0.14% AD).

Plasma, urine, and feces were examined for me tabolites at 30 minutes, 24 hours, and 24 hours, respectively. Only a single metabolite, DPX-MAT28, (the free acid of DPXKJM44) was
observed in each matrix. Identification was c onfirmed by comparison of mass spectrograph data from the experimental matrices with data obtai ned from fortified control plasma, and fortified pre-dose urine and feces. In a concurrently revi ewed subchronic oral toxicity study in rats (MRID 47573403), a metabolite (IN-LTX69) was quantif ied in plasma; however, this metabolite was not detected in the present study follo wing a single dose of the test compound.

Control pooled plasma samples and pre-dose urine and fecal samples were fortified with radiolabeled DPX-KJM44 dosing solution to determ ine stability at 3 (feces), 10 (urine), and 14 (plasma) days. No noticeable differences were obse rved in the urine and feces or in the prepared sample extracts. However, the majority of DPX-KJM44 in plasma was metabolized to DPXMAT28 when the sample was fortified and anal yzed on the same day. Once the plasma was extracted, DPX-KJM44 appeared to be stable.

This metabolism study is classified Acceptable/Guideline and satisfies the guideline requirement for a Tier 1 metabolism study [OPPTS 870.7485, OECD 417] in rats.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

Page 64 of 76Page 65 of 76 870.7600 Dermal Absorption – Rat

No study was submitted. This study was recomme nded for a waiver in a Memorandum entitled “Waivers of conditionally required to xicology studies for non-food uses of aminocyclopyrachlor” ( J. Ryman, February 4, 2010, D373897) because a dermal absorption factor of 100% was assumed and was appropriate for risk assessment of the proposed non-food

uses. 870.7800 Immunotoxicity-Rat

EXECUTIVE SUMMARY : In an immunotoxicity study (MRID 47560025) DPX-MAT28 (Aminocyclopyrachlor; 92.2% a.i.; Batch No. DPX-MAT28-009) was administered to ten male Sprague Dawley (Crl:CD[SD]) rats/dose group in the diet at dose le vels of 0, 600, 6,000 or 18,000 ppm (equivalent to 0, 42, 407, and 1277 mg/kg bw/day) for 28 days. An additional group of five rats were dosed by intr aperitoneal injection (10 mL/kg) with 25 mg/kg cyclophosphamide monohydrate to serve as positive controls. System ic toxicity parameters were evaluated, and immunotoxicity was investigated by performi ng an enzyme-linked immunoabsorbant assay (ELISA) to measure serum IgM responses to sheep red blood cells (sRBC) following
immunization with sRBC.

Systemic toxicity was not observed. There were no effects of treatment on mortality, clinical signs, body weights, body weight gains, food cons umption, food efficiency, organ weights, or gross pathology at any dose level.

The LOAEL for systemic toxicity was not obs erved. The NOAEL for systemic toxicity is 18,000 ppm (equivalent to 1277 mg/kg bw/day in males).

There was no evidence of immunotoxicity. No effects of treatment were observed on the humoral immune response as measured by the primary serum IgM antibody response to the Tdependent antigen, sheep erythrocytes. Spl een and thymus weights were unaffected by

treatment.

Positive control rats demonstrated an 82% decrease in Log 2 titer compared to concurrent controls, demonstrating the abilit y of this ELISA to detect suppression of the humoral immune

response.

The LOAEL for immunotoxicity was not obs erved. The NOAEL for immunotoxicity is 18,000 ppm (equivalent to 1277 mg/kg bw/day in males).

This immunotoxicity study is classified Acceptable/Guideline and satisfies the guideline requirements (OPPTS 870.7800) for an immunotoxicity study in rats.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.870.7800 Immunotoxicity-Mouse

EXECUTIVE SUMMARY : In an immunotoxicity study (MRID 47560026) DPX-MAT28 (Aminocyclopyrachlor; 92.2% a.i.; Batch Nos. DPX-MAT28-009) was administered to ten male CD-1 (Crl:CD[ICR]) mice/dose group in the diet at dose levels of 0, 300, 3,000 or 7,000 ppm (equivalent to 0, 45, 425, and 1056 mg/kg bw/day) for 28 days. An additional group of five mice were dosed by intraperitoneal injection (10 mL/kg) with 25 mg/kg cyclophosphamide monohydrate to serve as positive controls. System ic toxicity parameters were evaluated, and immunotoxicity was investigated by performi ng an enzyme-linked immunoabsorbant assay (ELISA) to measure serum IgM responses to sheep red blood cells (sRBC) following
immunization with sRBC.

Systemic toxicity was not observed. There were no effects of treatment on mortality, clinical signs, body weights, body weight gains, food cons umption, food efficiency, organ weights, or gross pathology at any dose level.

The LOAEL for systemic toxicity was not obs erved. The NOAEL for systemic toxicity is 7000 ppm (equivalent to 1056 mg/kg bw/day in males).

There was no evidence of immunotoxicity. No effects of treatment were observed on the humoral immune response as measured by the primary serum IgM antibody response to the Tdependent antigen, sheep erythrocytes. Spl een and thymus weights were unaffected by

treatment.

Positive control mice demonstrated a 73% decrease in Log 2 titer compared to concurrent controls, demonstrating the abilit y of this ELISA to detect suppression of the humoral immune

response.

The LOAEL for immunotoxicity was not obs erved. The NOAEL for immunotoxicity is 7000 ppm (equivalent to 1056 mg/kg bw/day in males).

This immunotoxicity study is classified Acceptable/Guideline and satisfies the guideline requirements (OPPTS 870.7800) for an immunotoxicity study in mice.

COMPLIANCE : Signed and dated Data Confiden tiality, GLP Compliance, and Quality Assurance statements were provided.

A.3.9 Special/Other Studies

Non-Guideline 14-Day Oral Toxicity Study-Rabbit

EXECUTIVE SUMMARY: Cyclopropane carboxylic acid has been identified as an environmental degradate of aminocyclopyrachlor that is of concern. There are no toxicity studies with cyclopropan e carboxylic acid suitable for risk a ssessment. However, cyclopropane carboxylic acid is also a metabolite of a drug cal led panadiplon, the toxic effects of which are

Page 66 of 76mediated by cyclopropane carboxylic acid. Theref ore, the following study from the general
scientific literature w ith panadiplon was used.

In a 14-day oral toxicity study, micronized panadiplon (pur ity unknown, batch/lot unknown), which is metabolized to cyclopropane carboxyl ic acid, was administered to Dutch-belted rabbits/dose orally (via gavage) in 1.25% low viscosity, microcry stalline cellulose and sodium carboxymethylcellulose NF, 0.2% polysorbate NF food grade, and 0.1N sodium hydroxide in purified water USP without sorbic acid at dose levels of 0 mg/kg (9 rabbits), 10 mg/kg (10 rabbits), or 20 mg/kg (10 rabbits) per day.

In 20 mg/kg animals, there was treatment relate d mortality in 2/10 rabb its and clinical signs (lethargy and weakness) in 6/10 rabbits. Both treated groups had gross liver lesions (white streaks and masses on the liver from a few mm up to 2 cm) in 4/10 animals (10 mg/kg) and 10/10 animals (20 mg/kg). Serum triglycerides were elevated on Day 14 only for 10 mg/kg animals, whereas 20 mg/kg animals had elevated serum tr iglycerides from Day 4 onward and elevated serum liver enzyme (aspartic acid transcar bamylase) from Day 8 onward. Microvesicular hepatic steatosis was observed in all treated an imals. This was accompanied by single cell or
multi-cell centrilobular necrosis in 7/10 animals at 10 mg/kg and centrilobular necrosis or focal coagulative necrosis in 10/10 animals at 20 mg /kg. Inflammatory cells and fibrosis were observed in larger necrotic foci th at corresponded with gross lesions.

The LOAEL for panadiplon is 10 mg/kg/day based on gross liver lesions a nd microscopic effects of microvesicular hepatic st eatosis and necrosis. The NOAEL was not observed.

The LOAEL for panadiplon (LOAEL P ) was converted to a LOAEL for CPCA (LOAEL C ) based on molecular weight and mole fraction, assumi ng a metabolic conversion of panadiplon to cyclopropane carboxylic acid of 100%. 100% was a ssumed because no experimental data were available regarding the percent conversion of panadiplon to cyclopr opane carboxylic acid.

LOAEL P = 10 mg/kg/day x [(86.09 g CPCA/mole) / (337.35 g panadiplon/mole)] x [1 mole CPCA/mole panadiplon]= 2.55 mg/kg/day = LOAEL C

The LOAEL for cyclopropane carboxylic acid is 2.5 mg/kg/day, based on gross liver lesions and microscopic effects of microvesicular hepa tic steatosis and necrosis. The NOAEL was

not observed.

This 90-day oral toxicity study in female Dutch-belted rabbit acceptable/non-guideline

.

COMPLIANCE : Signed and dated GLP, Quality Assurance, and Data Confidentiality

statements were not provided.

OECD 415 One Generation Reproduction-Rat

EXECUTIVE SUMMARY: In a non-guideline one-genera tion reproduction toxicity study (MRID 47560018), IN-KJM44 (Aminocyclopyrachlo r-methyl; 99.7% a.i.; Lot # 027) was administered in the diet to 10 Sprague Dawley rats/sex/dose group at dietary levels of 0, 600, 5000, or 17,000 ppm (equivalent to an averag e of 0/0, 49/53, 398/435, and 1378/1489 mg/kg/day

Page 67 of 76in P and F1 generation males/females during pre- mating). The P generation animals were fed the test diets for at least 28 days prior to mating to produce the F1 litters. Dams were allowed to deliver and rear their offspring until weaning on post-natal day (PND) 21. The F1 litters were culled to 4 pups/sex/litter (lit ter size permitting) on PND 4. In addition to the parameters typically evaluated in a repr oductive toxicity study, hemato logy and clinical chemistry evaluations were performed on 5 rats/sex/d ose from the P generation on Day 29 and at
termination. Neurobehavioral ev aluations (functional observationa l battery and motor activity measurements) were conducted on all P generation male (day 27) and female (day 28) animals during the pre-test period. At weaning, 10 F1 ra ts/sex/group were randomly selected to continue on study and were fed the same test diet concen tration as their dam until termination at PND 60.

One P male was found dead on Day 6; however, th is mortality was not considered treatmentrelated because no clinical signs of toxicity were observed in this animal prior to death, and no gross lesions were noted at ne cropsy. All other P and F1 ma les and females survived to
scheduled termination. No treatme nt-related effects were observed on clinical signs, FOB, motor activity, hematology, clinical chemistry, organ weights, gross pathology, or histopathology.

At 17,000 ppm, during the pre-mating period, food efficiency was decreased by 27% (p<0.01) for Days 0-7 in the P males compared to cont rols. In the P females at this dose, food consumption was decreased (p<0.05) by 11-15% for Days 0-7 and 7-14 and for the overall (Days 0-28) pre-mating period. However, body weights and body weight gains of the treated P females were unaffected by treatment. Body weights an d body weight gains of the treated P males were comparable to controls throughout pre-mating, post-mating period (Days 28-60), and for the overall study (PND 0-60). In the P dams, body we ights, body weight gains, food consumption, and food efficiency were unaffected by tr eatment throughout gest ation and lactation.

In the F1 adults at 17,000 ppm, body weights were decreased by 8-17% (p<0.05) in the males from Day 0 and continuing through Day 21 and by 11-15% in the females on Days 0 and 7. Food consumption was decreased (p<0.05) by 9- 17% in the males for Days 0-7, 14-21, 21-28, and 0-39 and by 8% in the females for Days 0-39.

The LOAEL for parental toxicity is 17,000 ppm (equivalent to 1378/1489 mg/kg/day in males/females), based on decreased food consum ption and efficiency in the P generation and on decreased body weights and food consumption in the F1 generation. The NOAEL is 5000 ppm (equivalent to 398/435 mg/k g/day in males/females).

There were no effects of treatment on sex ratio or on gestation, live birth, viability, lactation, or litter survival indices during th e post-natal period. Sexual matu ration, organ weights, and gross pathology were unaffected by treatment.

At 17,000 ppm, eight pups from one litter were dehydrated compared to 0 controls. F1 pup body weights were decreased (p <0.05) by 9% on PND 14 and by 17% on PND 21 compared to controls. Pup body weight gains for the overall post-natal period (PND 0-21) were decreased (NS) by 20% compared to controls.

Page 68 of 76The LOAEL for offspring toxicity is 17,000 ppm (equivalent to 1378/1489 mg/kg/day in males/females), based on dehydration, decreased pup body weight gains, and decreased pup body weights late in lactation. The NOAEL is 5000 ppm (equivalent to 398/435 mg/kg/day in males/females).

There were no effects of treatment on mating or fertility indices, gestat ion duration, number of implantation sites, implantation efficiency, or post -implantation loss. Pre-coital duration was not reported, and sperm parameters were not measure d. Estrus cycle stage for the pre-mating period was not reported. Microscopic examination of th e vagina at study termination did not indicate any effects of treatment on the estrus cycle stage.

The LOAEL for reproductive toxicity was not observed. The NOAEL is 17,000 ppm (equivalent to 1378/1489 mg/kg/ day in males/females).

This study is classified as an Acceptable/Non-guideline one-generation reproduction study in

rats.

COMPLIANCE : Signed and dated Data Confidentia lity, GLP Compliance, Flagging, and Quality Assurance statements were provided.

A.4 References (In MRID Order)

47559809 Anand, H. (2007) DPX-MAT28: Labor atory Study of Physicochemical Properties for Color, Odor, Physical State, Melting Po int, Boiling/Decomposition, Relative Density and Bulk Density. Project Number: G4781, DUPONT/22551. Unpublished study prepared by Advinus Therapeutics Private Limited. 35 p.

47559812 Moorthy, M. (2007) DPX-MAT28: Laboratory Study of pH. Project Number: G4785, DUPONT/22543. Unpublished study prepar ed by Advinus Therapeutics Private Limited. 19 p.

47559814 Anand, H. (2007) DPX-MAT28: Labor atory Study of Dissociation Constants in Water. Project Number: G4789, DUPONT/2255 5. Unpublished study prepared by Advinus Therapeutics Private Limited. 28 p.

47559815 Manjunatha, S. (2007) DPX-MAT2 8: Laboratory Study of n-Octanol/ Water Partition Coefficient. Project Number: G4782, DUPONT/22544. Unpublished study prepared by Advinus Therapeutics Private Limited. 63 p.

47559816 Moorthy, M. (2007) DPX-MAT28: Labor atory Study of Water Solubility. Project Number: G4783, DUPONT/22541. Unpublished st udy prepared by Advinus Therapeutics Private Limited. 46 p.

47559818 Moorthy, M. (2007) DPX-MAT28: La boratory Study of Vapour Pressure. Project Number: DUPONT/22537, G4780. Unpublished st udy prepared by Advinus Therapeutics Private Limited. 57 p.

Page 69 of 7647559820 Hirata, C. (2008) DPX-MAT28: Volat ility, Calculation of Henry's Law Constant. Project Number: DUPONT/22545/EU. Unpublished study prepared by E. I. Du Pont De Nemours and Co., Inc. 8 p.

47573401 Moorthy, M. (2007) DPX-MAT28: Laboratory Study of UV-VIS Absorption Spectrum and Molar Absorptivity. Proj ect Number: G4784, DUPONT/22536. Unpublished study prepared by Advinus Therapeutics Private Limited. 35 p.

47559828 Shalini, L. (2007) DPX-KJM44: La boratory Study of Physicochemical Properties for Color, Odor, Physical State, Melting Po int, Boiling Point/Decomposition and Relative Density. Project Number: G4792, DUPONT/23307. Unpublished st udy prepared by Advinus Therapeutics Private Limited. 32 p.

47559829 Shalini, L. (2007) DPX-KJM44: La boratory Study of Physicochemical Properties for Color, Odor, Physical State and Bulk Density. Project Number: G4890, DUPONT/22552. Unpublished study prepared by Advinus Therapeutics Private Limited. 22 p.

47559832 Moorthy, S. (2007) DPX-KJM44: Laboratory Study of pH. Project Number: G4796, DUPONT/22532. Unpublished study prepar ed by Advinus Therapeutics Private Limited. 20 p.

47559833 Moorthy, M. (2007) DPX-KJM44: Laboratory Study of UV-VIS Absorption Spectrum and Molar Absorptivity. Proj ect Number: G4795, DUPONT/22546. Unpublished study prepared by Advinus Therapeutics Private Limited. 38 p.

47559834 Manjunatha, S. (2007) DPX-KJM4 4: Laboratory Study of N-Octanol/Water Partition Coefficient. Project Number : DUPONT/22533, G4793. Unpublished study prepared by Advinus Therapeutics Private Limited. 34 p.

47559835 Moorthy, M. (2007) DPX-KJM44: Labor atory Study of Water Solubility. Project Number: G4794, DUPONT/22530. Unpublished st udy prepared by Advinus Therapeutics Private Limited. 33 p.

47559902 Moorthy, M. (2007) DPX-KJM44 (PAI): Laboratory Study of Vapour Pressure. Project Number: DUPONT/22547, G4791. Un published study prepared by Advinus Therapeutics Private Limited. 49 p.

47559934 Carpenter, C. (2007) DPX-MAT28 Tec hnical: Acute Oral Toxicity Study in RatsUp-and-Down Procedure. Project Nu mber: DUPONT/22371, 17181, 834. Unpublished study prepared by E.I. du Pont de Nemours and Company. 27 p.

47559935 Carpenter, C. (2007) DPX-MAT28 Techni cal: Acute Dermal Toxicity Study in Rats. Project Number: DUPONT/22370, 17181, 673. Unpublished study prepared by E.I. du Pont de Nemours and Company. 32 p.

Page 70 of 7647560001 Anand, S. (2007) DPX-MAT28 Technical : Inhalation Median Lethal Concentration (LC50) Study in Rats. Project Number: 22373. U npublished study prepared by E.I. du Pont de Nemours and Company. 42 p.

47560002 Carpenter, C. (2007) DPX-MAT28 Techni cal: Acute Eye Irritation Study in Rabbits. Project Number: 22372. Unpublished study prepared by E.I. du Pont de Nemours and Company. 21 p.

47560003 Carpenter, C. (2007) DPX-MAT28 T echnical: Acute Dermal Irritation Study in Rabbits. Project Number: 22369. Unpublished study prepared by E.I. du Pont de Nemours and Company. 22 p.

47560004 Carpenter, C. (2007) DPX-MAT28 Tec hnical: Local Lymph Node Assay (LLNA) in Mice. Project Number: 22374. Unpublished study prepared by E.I. du Pont de Nemours and Company. 36 p.

47560007 Anand, S. (2008) DPX-MAT28 Techni cal: Subchronic Toxicity 90 Day Feeding Study in Rats. Project Number: 21490. Unpublishe d study prepared by E.I. du Pont de Nemours and Company. 30 p.

47560008 Anand, S. (2008) DPX-KJM44 Techni cal: Subchronic Toxicity 90-Day Feeding Study in Rats. Project Number: 22570. Unpublished study prepared by E.I. du Pont de Nemours and Company, Critical Path Services, LLC, and Histo Techniques, Ltd. 438 p.

47560009 Anand, S. (2007) DPX-KJM44 Techni cal: Subchronic Toxicity 90-Day Feeding Study in Rats. Project Number: 21491. Unpublished study prepared by E.I. du Pont de Nemours and Company. 30 p.

47560010 Anand, S. (2008) DPX-MAT28 Techni cal: Subchronic Toxicity 90-Day Feeding Study in Mice. Project Number: 21491. Unpub lished study prepared by E.I. du Pont de Nemours and Company. 403 p.

47560011 Anand, S. (2008) DPX-MAT28 Techni cal: Subchronic Toxicity 90 Day Feeding Study in Mice. Project Number: 21491. Unpub lished study prepared by E.I. du Pont de Nemours and Company. 26 p.

47560012 Luckett, E. (2008) DPX-MAT28 Tec hnical: Subchronic Toxicity 90-Day Feeding Study in Dogs: Revised Final Report. Pr oject Number: DUPONT/21489, 125/068. Unpublished study prepared by MPI Research, Inc. 841 p.

47560013 Luckett, E.; Mawn, M. (2008) DPX- MAT28 Technical: Subchronic Toxicity 90 Day Feeding Study in Dogs. Project Nu mber: DUPONT/21489, 125/068. Unpublished study prepared by E.I. du Pont de Nemours and Company. 27 p.

47560014 Merkel, D. (2008) DPX-MAT28 Techni cal: Dermal Toxicity Study (28 Day Repeat Dermal Application Study in Rats). Project Number: DUPONT/22796, 22352. Unpublished

Page 71 of 76study prepared by Product Safety Laboratories, E.I. du Pont de Nemours and Company and Charles River Breeding Labor atories, Inc. 207 p.

47560015 Fleeman, T. (2008) A Prenatal Deve lopment Toxicity Study of DPX-MAT28 in Rabbits: Revision 2 Final Report. Project Number: WIL/189193, DUPONT/22377. Unpublished study prepared by WIL Res earch Laboratories, Inc. 690 p.

47560016 Lewis, J. (2008) DPX-MAT28 Technical : Developmental Toxicity Study in Rats. Project Number: DUPONT/22378, 07/CPS/032. Unpublis hed study prepared by E.I. du Pont de Nemours and Company and Critical Path Services, LLC. 372 p.

47560018 Lewis, J. (2006) IN-KJM44: One-Ge neration Reproduction Study in Rats. Project Number: DUPONT/17315. Unpublished study prepar ed by E.I. du Pont de Nemours and Company. 741 p.

47560019 Wagner, V.; VanDyke, M. (2008) DPX-MAT28 Technical: Bacterial Reverse Mutation Assay. Project Number: AC02HJ/503/BTL, 17293, H/27937. Unpublished study prepared by Bioreliance and D upont Haskell Laboratory. 73 p.

47560020 Clarke, J. (2007) DPX-MAT28 Techni cal: In vitro Mammalian Cell Gene Mutation Test (CHO/HGPRT Assay). Project Number: AC02HJ/782/ BTL, 17293, 515. Unpublished study prepared by Bioreliance and Dupont Haskell Laboratory. 48 p.

47560021 Gudi, R.; Rao, M. (2007) DPX- MAT28 Technical: In vitro Mammalian
Chromosome Aberration Test in Human Peripheral Blood Lym phocytes. Project Number: AC02HJ/341/BTL, DUPONT/22709, 17293. Unpublishe d study prepared by Bioreliance. 58 p.

47560022 Krsmanovic, L.; Huston, T. (2007) DPX-MAT28 Technical: Mouse Bone Marrow Erythrocyte Micronucleus Tes t: Final Report. Project Number: AC02HJ/123/BTL, 17293, 572. Unpublished study prepared by Dupont Haskel l Laboratory and Bioreliance. 57 p.

47560023 Himmelstein, M. (2008) [Carbon 14]-D PX-MAT28: Plasma Pharmacokinetics and
Pilot Material Balance in Male and Female Rats. Pr oject Number: DUPONT/22033, 17124, 1017. Unpublished study prepared by E.I. du Pont de Nemours and Company. 91 p.

47560024 Himmelstein, M. (2008) [carbon 14]-D PX-KJM44: Plasma Pharmaconkinetics and
Pilot Material Balance in Male and Female Rats. Pr oject Number: DUPONT/22375, 17271, 1017. Unpublished study prepared by E.I. du Pont de Nemours and Company. 90 p.

47560025 Hoban, D. (2008) DPX-MAT28 Tec hnical: 28-Day Immunotoxicity Feeding Study in Male Rats . Project Number: DUPONT /22794, 17286, 1545. Unpublished study prepared by E.I. du Pont de Nemours and Company, Critical Path Services, LLC, and ImmunoTox, Inc. 93 p.

47560026 Hoban, D. (2008) DPX-MAT28 Tec hnical: 28-Day Immunotoxicity Feeding Study in Male Mice. Project Number: DUPONT /22795, 17286, 1546. Unpublished study prepared by E.I. du Pont de Nemours and Company, Critical Path Services, LLC, and ImmunoTox, Inc. 99 p.

Page 72 of 7647560027 Carpenter, C. (2007) DPX-KJM44 Tec hnical: Acute Oral Toxicity Study in RatsUp-and-Down Procedure. Project Nu mber: DUPONT/22950, 17251, 834. Unpublished study prepared by E.I. du Pont de Nemours and Company. 28 p.

47560028 Carpenter, C. (2007) DPX-KJM44 Techni cal: Acute Dermal Toxicity Study in Rats. Project Number: DUPONT/22951, 17251, 673. Unpublished study prepared by E.I. du Pont de Nemours and Company. 29 p.

47560029 O'Neal, F. (2008) DPX-KJM44 Tec hnical: Acute Inhalation Toxicology Test Waiver. Project Number: DUPONT/26475. U npublished study prepared by DuPont Crop Protection. 11 p.

47560030 Carpenter, C. (2007) DPX-KJM44 Tec hnical: Acute Eye Irritation Study in Rabbits. Project Number: DUPONT/23435, 602, 17251. Unpublished study prepared by E.I. du Pont de Nemours and Company. 21 p.

47560031 Carpenter, C. (2007) DPX-KJM44 T echnical: Acute Dermal Irritation Study in Rabbits. Project Number: DUPONT/22952, 17251, 1008. Unpublished study prepared by E.I. du Pont de Nemours and Company. 22 p.

47560032 Carpenter, C. (2008) DPX-KJM44 Tec hnical: Local Lymph Node Assay (LLNA) in Mice. Project Number: DUPONT/23436, 17251, 1234. Unpublished study prepared by E.I. du Pont de Nemours and Company. 36 p.

47560033 Ford, L. (2005) IN-KJM44: Bacterial Reverse Mutation Test. Project Number: DUPONT/17971, 15744, 502. Unpublished study prepared by E.I. du Pont de Nemours and Company. 33 p.

47560211 Lowrie, C. (2008) Photodegradation of [Pyrimidine-2-(Carbon 14)]DPX-MAT28 in pH 4 Buffer and Natural Water by Simulated Sunlight: Final Report. Project Number: 212706, DUPONT/22117. Unpublished study prepared by Charles River Laboratories. 88 p.

47560213 Wardrope, L. (2008) Photodegradatio n of [Pyrimidine-2-(Carbon 14)]-DPX-MAT28 on Soil: Final Report. Project Number: DUPONT/22118, 807770. Unpublished study prepared by Charles River Laboratories. 76 p.

47573403 Anand, S. (2008) DPX-MAT28 Techni cal: Subchronic Toxicity: 90-Day Feeding Study in Rats. Project Number: DUPONT/ 21490, 17053, 1026. Unpublished study prepared by E.I. du Pont de Nemours and Company. 583 p.

47575101 Lewis, J. (2008) DPX-:MAT28 Tec hnical: Multi-Generation Reproduction Study in Rats. Project Number: 1 7123, 904, DUPONT/22032. Unpublished study prepared by E.I. du Pont de Nemours and Company. 1642 p

.
47725701 O'Neal, F. (2009) Aminocyclopyrachl or (DPX-MAT28) Technical Registration: Waiver Request for the 90-Day Dermal T oxicity Study. Project Number: DUPONT/27949. Unpublished study prepared by DuPont Crop Protection. 10 p.

Page 73 of 76Page 74 of 76 47725702 Barnett, J. (2009) Oral (Gavage) Acute Neurotoxicity St udy of DPX-MAT28-009 in Rats. Project Number : AUV00038, DUPONT/22792, WR/17270/ SC/1261. Unpublished study prepared by Charles River Laboratories. 530 p.

47898501 O'Neal F.; Snyder, N.; Hirata, C. (2 009) IN-V0977: Exposure and Risk Assessments of Photolytic Decomposition Product of Ami nocyclopyrachlor (DPX-MAT28). Project Number: DUPONT/29367. Unpublished study prepared by E.I. Du Pont de Nemours and Company. 41 p.

47916803 Ulrich, R.; Bacon, J.; Branstetter, D.; et al. (1994) Induction of a Hepatic Toxic Syndrome in the Dutch-Belted Rabbit by a Quinoxalinone Anxiolytic. Toxicology 98: 187-198.Appendix B: Review of Human Research

The PHED Task Force, 1995. The Pesticide Handlers Exposure Database, Version 1.1.
Electronic Database. Task Force members Heal th Canada, U. S. Environmental Protection Agency, and the National Agricultural Chemi cals Association, rele ased February, 1995.

Appendix C: Chemical Stru ctures of Degradates

The following chemical structures of the 5 environmental degradates of aminocyclopyrachlor were obtained from HED’s “Aminocyclopyrachlor. Report of the Residues of Concern Knowledgebase Subcommittee (ROCKS)” memo randum (from G. Kramer, October 15, 2009, D370638).

Degradate 1: IN-LXT69

IUPAC Name: 5-Chloro-2-cyclopropyl-pyrimidin-4-ylamine

CAS Name : Not reported

CAS. No.: Not reported

N N NH

2 Cl

Degradate 2: IN-QFH57

IUPAC Name: 4-Cyano-2-cyclopropyl-1H-i midazole-5-carboxylic acid

CAS Name : 4-Cyano-2-cyclopropyl-1H-imi dazole-5- carboxylic acid

CAS. No.: Not reported

HN N OH O N

Page 75 of 76Page 76 of 76 Degradate 3: IN-Q3007

IUPAC Name: Cyclopropanecarboxamide

CAS Name : Cyclopropanecarboxamide

CAS. No.: 6228-73-5

O N H

H

Degradate 4: IN-V0977

IUPAC Name: Cyclopropanecarboxylic acid

CAS Name : Cyclopropanecarboxylic acid

CAS. No.: 1759-53-1

O OH

Degradate 5: IN-YY905

IUPAC Name: Cyclopropanecarboximidamide

CAS Name : Cyclopropanecarbamidine

CAS. No.: Not reported

NH NH

2