Page 3 of 70

5. 4 .2 Chronic and Cancer Dietary Exposure and Risk

................................ ................... 2 3

6.0 RESIDENTIAL EXPOSURE AND RISK

................................ ................................ ........ 2 4

6.1 Residential Bystander Postapplication Inhalation Exposure

................................ ............. 2 4

6.2 Spray Drift

................................ ................................ ................................ ......................... 2 5

7.0 AGGREGATE EXPOSURE AND RISK ASSESSMENT

................................ ............... 2 5

7.1 Short

- Term Aggregate Risk to Residential Applicators

................................ .................... 2 6

7.2 Short

- Term Aggregate Risk for Residen tial Post

- Application Exposure

.......................... 2 6

8.0 CUMULATIVE RISK

................................ ................................ ................................ ....... 2 7

9.0 OCCUPATIONAL EXPOSURE AND RISK

................................ ................................ ... 2 8

9 .1 Handler Exposure

................................ ................................ ................................ .............. 2 8

9.1.1 Handler Exposure Scenarios

................................ ................................ .................. 2 8

9.1.2 Handler Exposure Data and Assumptions

................................ ............................. 2 9

9.1.3 Handler Exposure and Risk Estimates

................................ ................................ ... 2 9

9.2 Post Applicatoin Exposure

................................ ................................ ................................ 31

9.2.1 Post Application Exposure Scenarios

................................ ................................ .... 32

9.2.2 Post Application Exposure Data and Assumptions for Field Crops

...................... 32

9.2.3 Post Application Exposure Data and Assumptions for Post Harvest Potato

......... 3 3

9.2.3 Post Application Exposure and Risk Estimates

................................ ..................... 3 3

10.0 REFERENCES

................................ ................................ ................................ .................. 3 5

Appendix A. Toxicity Profile and Executive Summaries

................................ .............................. 3 6

A.1 Toxicity Data Requirements

................................ ................................ .................. 3 6

A.2 Toxicity Profiles

................................ ................................ ................................ ..... 3 7

A.3 Hazard Identification and Endpoint Selection

................................ ....................... 42

A.4 Executive Summaries

................................ ................................ ............................. 4 4 Appendix B. Metabolism

................................ ................................ ................................ .............. 6 4 Appendix C. Physical/Chemical Properties

................................ ................................ ................... 70 Appendix D. Review of Human Research

................................ ................................ ..................... 70Page 4 of 70

1.0 EXECUTIVE SUMMARY

This assessment provides information to support amended Section 3 registrations for the new postharvest use of difenoconazole on Tuberous and Corm Vegetables Subgroup 1C and the expansion of currently registered foliar uses for fruiting vegetables, citrus fruits, pome fruits, and strawberries to include the additional commodities specified under Fruiting Vegetables Group 8

- 10, Citrus Fruits Group 10

- 10, Pome Fruits Group 11

- 10, and Low growing Berry Subgroup 13

- 07G, Except Cranberry. This document assesses dietary and drinking water risks associated with

exposures resulting from currently registered and proposed ne w uses of and tolerances for

difenoconazole

. It also assesses potential enhanced sensitivity of infants and children from dietary and/or residential exposure as required under the Food Quality Protection Act (FQPA) of

1996.

Use Profile

Difenoconazole i s a broad spectrum fungicide belonging to the triazo le group of fungicides . It is currently registered in the U.S. for use as a seed treatment on barley, canola, cotton, sweet corn, wheat, and triticale and for foliar application to numerous food crops an d

ornamentals . Tolerances for difenoconazole

, currently established under 40 CFR §180.475

, range from 0.01

- 95 ppm . Difenoconazole acts by blocking demethylation during sterol biosysnthesis which, in turn, disrupts membrane synthesis . Difenocon a zole is a vailable as

emulsifiable concentrate , soluble concentrate , emulsion [oil] in water, flowable suspension, and ready

- to

- use formulations. As a seed treatment, it is applied with commercial grade seed treatment equipment. As a foliar treatment, it is applie d to field and vegetable crops

, landscape

ornamentals and golf course turf by commercial applicators using aerial and ground application methods and equipment. It is applied to ornamentals by residential applicators using hand held

sprayers.

Proposed N ew Use s

The Interregional Research Project No. 4 (IR

- 4) is requesting the following actions.

1) Establishment of tolerances for residues of difenoconazole in/on Fruiting Vegetables Group 8

- 10, Citrus Fruits Group 10

- 10, Pome Fruits Group 11

- 10, and Low growing Berry Subgroup 13

- 07G, Except Cranberry. 2) An increase in the existing tolerance in/on Vegetable, tuberous and corm, subgroup 1C from 0.01 ppm to 4.0 pp m; 3) Removal of existing tolerances in/on potato, processed waste, fruiting vegetable (group 8), citrus (group 10), pome fruit(group 11), and strawberry; 4) An amendment for the Section 3 registration for Thesis TM Fungicide (EPA Reg. No. 100

- 1386) to add a postharvest use on Vegetables, tuberous and corm, subgroup 1C (1 application at 0.0070 lb ai/ton tubers); and 5) Amendments for the Section 3 registrations for InspireTM Fungicide (EPA Reg. No. 100

- 1262)

, Inspir eTM XT Fungicide ( EPA Reg. No. 100

- 1312)

, Quadris TopTM Fungicide ( EPA Reg. No. 100

- 1313) and I nspire Super TM Fungicide ( EPA Reg. No. 100

- 1317 ) to expand currently registered foliar uses for fruiting vegetables, citrus fruits, pome fruits,Page 5 of 70

and strawberries t o include the additional commodities specified under the following new crop groups/subgroup; Fruiting Vegetables Group 8

- 10, Citrus Fruits Group 10

- 10, Pome Fruits Group 11

- 10, and Low growing Berry Subgroup 13

- 07G, Except Cranberry. No substantive change s to the currently registered foliar use patterns on the subject crops have been proposed.

Hazard Identification

Subchronic and chronic toxicity studies with difenoconazole in mice and rats showed decreased body weights, decreased body weight gains an d effects on the liver. Acute and subchronic neurotoxicity studies showed evidence of neurotoxic effects. However, the observed

effects were transient and the dose

- response was well characterized with identified dose levels at

which no observed adverse ef fects were seen. The available toxicity studies indicated no increased susceptibility of rats or rabbits from in utero or postnatal exposure to difenoconazole.

There are no indications of immunotoxicity in the available studies

. No evidence of carcinogenicity was seen in the chronic/cancer rat study . Evidence for carcinogenicity was seen

in mice as induction of liver tumors at doses which were considered to be excessively high for carcinogenicity testing. Difenoconazole has been classified as “Suggestive Evidence of Carcinogenic Potential” with risk quanti fied using a non

- linear (Margin of Exposure) approach

. The cancer classification is based on excessive toxicity observed at the two highest doses, the

absence of tumors at the lower doses and the absence of genotoxic effects. The FQPA Safety

Factor is reduced to 1 X

. Difenoconazole exhibits low acute toxicity by the oral, dermal and inhalation routes of exposure. It is not an eye or skin irritant and is not a sensitizer.

The toxicological database for difenoconazole is sufficient to conduct this risk

assessment. An immunotoxicity study, required under Part 158 Toxicology Data requirements,

has been submitted an d is under review.

Dose Response Assessment

Toxicological poin ts of departure (PODs) were selected for dietary and drinking water

exposures for the assessment of proposed new uses of difenoconazole

. Acute and chronic PODs were selected for assessment of food and water exposures. An acute POD for all populations

was selected from an acute neurotoxicity study in rats based on reduced grip strength

. A chronic

POD was selected from a c hronic/carcinogenicity study in rats based on body weight effects

. Short and intermediate

- term incidental oral, dermal and inhalation PODs were selected from a n oral rat reproduction study based on decreased body weight effects in pups and parental animals

. A dermal absorption factor is applied when dermal exposure endpoints are selected from oral toxicity studies. A dermal absorption factor of 6% was used for the dermal exposure assessment. Inhalation toxicity is assumed to be equivalent to oral toxicity. An uncertainty factor of 100X was applied endpoints selected for all exposure s routes (10 X for interspecies extr apolation, 10X

for intraspecies variation).Page 6 of 70

Exposure/Risk Assessment and Risk Characterization

Risk assessments were conducted for dietary (food and water) , occupational and aggregate exposure for the proposed new uses of difenoconazole

. A new residential assessment is not required because the proposed new use does not include residential applications or

exposures

. Screening level acute and refined chronic dietary and drinking water risk assessments
indicate that for all commodities, dietary an d drinking water exposure estimates are below

HED’s level of concern. Additionally, t he requested use s of difenoconazole result ed in an increase in dietary exposure estimates for free triazole or conjugated triazoles. Therefore, dietary exposure analyses for the triazole metabolites need ed to be updated (T. Morton, D397591, 1/26/12). R isk estimates for worker handler and post

- application exposure scenarios exposures

are not of concern at maximum use rate s for existing and proposed new uses. Aggregate risks

are not of concern.

Aggregate Assessment of Free Triazole & its Conjugates

The addition of the new proposed uses increase s the aggregate exposure to free triazoles and its conjugates. Therefore, the aggregate human health risk assessment was upd ated for free triazoles and its conjugates and the aggregate estimates remain below HED’s level of concern

.

Use of Human Studies

This risk assessment relies in part on data from studies in which adult human subjects were intentionally exposed to a pest icide or other chemical. These studies , listed in Appendix D have been determined to require a review of their ethical conduct . S ome of these studies are also subject to review by the Human Studies Review Board. All of the studies used have received the appropriate review.

2.0 HED RECOMMENDATIONS

2.1 Data Deficiencies

S ubmission of a revised Section B and a revised Section F are required (see Section 2.2.3)

. An immunotoxicity study, required under Part 158 Toxicology Data requirements, has been submitted and is under review. The Hazard and Science Policy Council ( HASPOC ) concluded based on a weight of evidence ( WOE) approach that a 28

- day inhalation toxicity study is not required at this time. This approach considered all of the availab le hazard and exposure information for difenoconazole, including: (1) the use of an oral POD that results in MOEs greater than 1,300 (the lowest MOE) for risk via the inhalation route resulting from occupational and residential; (2) the physical/chemical p roperties and very low vapor pressure of difenoconazole; and (3) the toxicological profile of difenoconazole.Page 7 of 70

2.2 Tolerance Considerations

2.2.1 Enforcement Analytical Method

An adequate enforcement method, GC/NPD method AG

- 575B, is available for the

determination of residues of difenoconazole per se in/on plant commodities

. An adequate enforcement method, LC/MS/MS method REM 147.07b, is available for the determination of

re sidues of difenoconazole and CGA

- 205375 in livestock commodities. Adequate confirmatory

methods are also available.

2.2.2 International Harmonization

Codex maximum residue levels (MRLs) for residues of difenoconazole per se have been

established at 0 .5 ppm for tomato; 0.5 ppm for pome fruits; and 0.02 ppm for potato. Based on the available magnitude of the residue data, harmonization with these established Codex MRLs is not possible because

, due to differences in good agricultural practices (GAP) the Codex MRLs

are too low to adequately cover residues resulting from the proposed use rates in the U.S

. Mexican and Canadian MRLs have been established for difenoconazole; however, no Mexican MRLs have been established for the requested crops. Canadian MR Ls for residues of

difenoconazole per se have been established at 0.6 ppm for a number of fruiting vegetables and 1.0 ppm for a number of pome fruit, and are in harmony with proposed U.S. tolerances. HED has been informed by RD that Canada has agreed to h armonize with the proposed U.S. tolerance for vegetable, tuberous and corm, subgroup 1C at 4.0 ppm.

2.2.3 Recommended Tolerances

HED has examined the residue chemistry database for difenoconazole and pending submission of a revised Section F (see requir ements under Revisions to Petitioned for Tolerances), there are no residue chemistry issues that would preclude es tablishment of tolerances for residues of difenoconazole only in/on the commodities listed b elow :

Vegetable, fruiting, group 8

- 10

................................ ................ 0.60 ppm Fruit, citrus, group 10

- 10

................................ .......................... 0.60 ppm Fruit, pome, group 11

- 10

................................ .......................... 1.0 ppm Berry, low growing, subgroup 13

- 07G, except cranberry

........ 2.5 ppm Vegetable, tuberous and corm, subgroup 1 C

............................ 4.0 ppm Potato, wet peel

................................ ................................ ......... 7.3 ppm

C urrently established tolerances for residues of difenoconazole in/on Vegetable, fruiting, group 8 (0.60 ppm); Fruit, citrus, group 10 (0.60 ppm); Fruit, pome group 11 (1.0 ppm); and Strawberry (2.5 ppm) should be removed.Page 8 of 70

Notes to PM:

1. A tolerance for Low growing berry subgroup 13

- 07G, except cranberry was specified in the Notice of Filing. Available data would support a tolerance in/on Berry, low growing, subgroup

13

- 07G. The petition is unclear as to why the petitioner wants to restrict the use on cranberry.

2. As directed by RD, the pr oposed use on Grapes and other small fruit vine climbing subgroup (except fuzzy kiwifruit) was not considered because the Notice of Filing did not include a tolerance proposal for this subgroup.

3. No data were submitted to address existing residue chem istry conditions of registration for the

end

- use products under consideration. Although not reiterated here, these data remain outstanding and are relevant to the current petition.

4. Use information was taken from Section B of the petition only. No additional draft labeling was provided for review. RD informed HED that the petitioner is requesting a postharvest use on all commodities listed under Vegetables, tuberous and corm, su bgroup 1C and not just potato as specified in Section B of the petition.

2.2.4 Revisions to Petitioned

- For Tolerances

HED’s recommended revisions to the tolerances and/or commodity definitions submitted by IR

- 4 for this Section 3 petition are liste d in Table 1. The proposed removal of the currently established tolerance for residues of difenoconazole on potato, processed waste is not appropriate; a tolerance is needed for residues of difenoconazole in potato, wet peel at 7.3 ppm.

Table 1

. Tolerance Summary for Difenoconazole.

Commodity Proposed

To lerance (ppm) Recommended

Tolerance (ppm) Correct Commodity Definition ;

Comments

Vegetable, fruiting, group 8

- 10 0.6 0.60

Fruit, citrus, group 10

- 10 0.6 0.60

Fruit, pome, group 11

- 10 1.0 1.0

Low growing berry subgroup 13

- 07G, except cranberry 2.5 2.5 Berry, low growing, subgroup 13

- 07G, except cranberry

Vegetable, tuberous and corm, subgroup 1C 4.0 4.0

Potatoes, proce ss ed waste remove 7.3 Potato, wet peel

Vegetable, fruiting, group 8 remove remove Fruit, citrus, group 10 remove remove Fruit, pome, group 11 remove remove Strawberry remove removePage 9 of 70

2.2.5 Label Recommendations

- For InspireTM Fungicide , Section B of the petition must be amended to: remove the

restriction for use on small tomatoes (page 25 of 68); and remove all use directions for grapes and other small fruit vine climbing except fuzzy kiwifruit (page 26 of 68).

- For InspireTM XT Fungicide , Section B of the petition must be amended to: remove all

use directions fo r bulb vegetables (page 41 of 68).

- For Quadris TopTM Fungicide , Section B of the petition must be amended to: remove the restriction for use on small tomatoes (page 39 of 68); and remove all use directions for grapes and other small fruit vine climbing e xcept fuzzy kiwifruit (page 36 of 68).

- For Inspire SuperTM Fungicide , Section B of the petition must be amended to: remove the restriction for use on small tomatoes (page 30 of 68); and remove all use directions for grapes and other small fruit vine climb ing except fuzzy kiwifruit (page 31 of 68).

- For ThesisTM Fungicide , Section B of the petition must be amended to: specify a maximum use rate of 0.0070 lb ai/ton of tubers (not just 0.3 fl. oz. product/ton of tubers); specify a delivery rate of 0.5 gal/ton of tubers; prohibit the use of adjuvants; and specify use on all tuberous and corm vegetables listed under subgroup 1C. . RD informed HED that the petitioner is requesting a postharvest use on all commodities listed under Vegetables, tuberous and corm, subgroup 1C and not just potato as specified in Section B of the petition.

- Concerning rotational crop restrictions and foliar uses under consideration: Although no information was provided on this topic in Section B of the petition, HED has determined

th at available data support a 30

- day plantback interval (PBI) for cereal and root/tuber

crops not already registered for foliar use with difenoconazole and a 60

- day PBI for all other crops not already registered for foliar use with difenoconazole.Page 10 of 70

3 .0 INGREDIENT PROFILE

3 .1 Chemical Identity

Table 2

. Structures and Nomenclature

. Chemical structure of

difenoconazole

Common name Difenoconazole

Company experimental name CGA

- 169374

IUPAC name 1

- ({2

- [2

- chloro

- 4

- (4

- chlorophenoxy)phenyl]

- 4

- methyl

- 1,3

- dioxolan

- 2

- yl}methyl)

- 1H

- 1,2,4

- triazole

CAS name 1

- [[2

- [2

- chloro

- 4

- (4

- chlorophenoxy)phenyl]

- 4

- methyl

- 1,3

- dioxolan

- 2

- yl]methyl]

- 1H

- 1,2,4

- triazole

CAS registry number 119446

- 68

- 3

End

- use product s (E P) InspireTM Fungicide ( 100

- 1262 ), InspireTM XT Fungicide ( 100

- 1312 ), Quadris TopTM Fungicide (100

- 1313), Inspire SuperTM Fungicide (100

- 1317), ThesisTM Fungicide (100

- 1386),

3.2 Physical/Chemical Characteristics

A d etailed description of the physio chemical properties of difenoconazole is provided in Appendix C. Difenoconazole exhibits relatively low solubility in water and higher solubility in solvents. It has a very low vapor pressure. Based on the field and laboratory studies,

difenoconazole is persistent in soil and slightly mobile. It has low potential to reach ground water, except in soils of high sand and low organic matter content. Difenoconazole does not present significant concerns for bioaccumulation based on the lipophilicity of the c ompound, as

well as the mammalian metabolism studies.

3

. 3 Pesticide Use Pattern

Difenoconazole is currently registered in the U.S. for use as a seed treatment on barley, wheat, and triticale , canola, sweet corn and cotton . It is also registered for foliar applications to numerous fruit and vegetable crops, ornamentals and golf course turf. Proposed new uses

include a post

- harvest use on potato . The use patterns for the amended use are provided in Table

3

.Page 11 of 70

Table 3. Summary of Proposed Amended Use for Difenoconazole

. Appl. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Max.

Appl. Rate (AR) (lb ai/A) Max. No.

Appl. per

Season Max.

Seasonal

AR (lb ai/A) PHI

(days) Use Directions and

Limitations

Potato PostHarvest (PH)

In

- line

aqueous spray application using T

- ject, CDA, or

similar application

system. 3.0 lb ai/gal

FS [100

- 1386] 0.3 fl. oz

of product/ton

of tubers 1 N/A N/A For treatment of certain postharvest rots caused by

Silver scurf ( Helminthosporium solani) and

Fusium species. Ensure proper coverage of the

tubers. Tubers should be tumbling as they are treated. Mix the fungicide solution in an appropriate amount of water for the crop being treated.

Must be used in tank mixture

with fludioxonil and azoxystrobin. Fruiting Vegetables Foliar, Broadcast, Ground, aerial, or chemigation 2.08 lb/gal

EC [100

- 1262] 0.114 Not Specified (NS) 0.46 0 A 7

- day minimum RTI is specified.

Do not use on varieties in

which the mature tomatoes will be less than 2 inches (such as cherry tomatoes). 1.05 lb/gal

MAI SC [100

- 1313] Peppers

0.115

Tomatoes

0.07 0.73 lb/gal

MAI EW [100

- 1317] 0.114

Citrus Fruits
Foliar, Broadcast,

Ground or

aerial 2.08 lb/gal

EC [100

- 1262] 0.125 NS 0.5 0 A 7

- day minimum RTI is specified.

1.05 lb/gal

MAI SC [100

- 1313] 0.126

Pome Fruits
Foliar, Broadcast,

Ground or

aerial 2.08 lb/gal

EC [100

- 1262] 0.07 NS 0.33 72

14 A 7

- day minimum RTI is specified.

0.73 lb/gal

MAI EW [100

- 1317] 0.07

Strawberries and other low growing berries (except cranberry)
Foliar, Broadcast, Ground ,

aerial or chemigation 2.08 lb/gal

EC [100

- 1262] 0.114 NS 0.46 0 A 7

- day minimum RTI is specified.

2.08 lb/gal

MAI EC [100

- 1312] 0.114

1.05 lb/gal

MAI SC 0.115Page 12 of 70

Table 3. Summary of Proposed Amended Use for Difenoconazole

. Appl. Timing, Type, and Equip. Formulation

[EPA Reg. No.] Max.

Appl. Rate (AR) (lb ai/A) Max. No.

Appl. per

Season Max.

Seasonal

AR (lb ai/A) PHI

(days) Use Directions and

Limitations

[100

- 1313] 0.73 lb/gal

MAI EW [100

- 1317] 0.114

3.4 Anticipated Exposure Pathways

Dietary (food and water) and occupational exposures are expected based on existing and proposed new use difenoconazole as a post harvest use on potato

. A new residential exposure assessment is not required because t here are no residential uses or exposures associated with the proposed new use

. The short

- term aggregate exposure assessment

, which takes into account residential exposure plus average ex posure leve ls to food and water, has been updated to incorporate dietary exposure from the proposed new uses.

3. 5 Considerations of Environmental Justice

Potential areas of environmental justice concerns, to the extent possible, were considered in this human health risk assessment, in accordance with U.S. Executive Order 12898, "Federal Actions to Address Environmental Justice in Minority Populations and Lo w

- Income Populations," http://www.eh.doe.gov/oepa/guidance/justice/eo12898.pdf ).

As a part of every pesticide risk assessment, OPP considers a large variety of consumer subgroups according to well

- established procedures. In line with OPP policy, HED estimates risks to population subgroups from pesticide exposures that are based on pat terns of that subgroup’s food and water consumption, and activities in and around the home that involve pesticide use in a residential setting. Whenever appropriate, non

- dietary exposures based on home use of pesticide products and associated risks for ad ult applicators and for toddlers, youths, and adults entering or playing on treated areas post application are evaluated. Further considerations are currently in development, as OPP has committed resources and expertise to the development of specialized s oftware and models that consider exposure to bystanders and farm workers as well as lifestyle and traditional dietary patterns among specific subgroups.

4 .0 HAZARD CHARACTERIZATION/ASSESSMENT

4 .1 Toxicology Studies Available for Analysis

T he toxicol ogy database for difenoconazole is adequate for evaluating and characterizing difenoconazole toxicity and selecting endpoints for purposes of this risk assessment. A ll toxicity studies required in accordance with new 40 CFR Part 158 the data requirements have been

submitted. An immunotoxicity study has been submitted and is under review.Page 13 of 70

4 .2 Absorption, Distribution, Metabolism and Excretion

The absorption, distribution, metabolism, and excretion of difenoconazole were studied

in rats. In one study, t he test compound was labeled with C 14 at either the phenyl or triazole ring. Animals were administered a single oral gavage dose of 0.5 or 300 mg/kg of radiolabeled compound or 0.5 mg/kg unlabeled compound by gavage for 14 days followed by a single gava ge dose of 0.5 mg/kg [ 14 C]

- difenoconazole on day 15. In a second follow

- up study [ 14 C]

- difenoconazole (phenyl ring label) was administered as single oral gavage dose of 0.5 or 300 mg/kg. The second study was conducted to address deficiencies in the initi al study by providing biliary excretion and identi fi cation of metabolites.

D ifenoconazole was rapidly absorbed and extensively distributed, metabolized, and excreted in rats for all dosing regimens. D istribution, metabolism and elimination of

difenoconazole were not sex related in the first study

. Recovery of administered dose was 96

- 108%

. Bil iary excretion

, examined in the second study

, constituted the main route of elimination with some dose and sex dependency (75% at the low dose for both sexes; 56% for males and 39% for females at the high dose). Ur inary and fecal eliminations exhibited a dose

- related pattern at 48 hours . In bile duct cannulated rats, 9

- l4% of dose was eliminated in the urine at the low dose versus 1% in the high

- dose ra ts. In bile duct cannulated rats, 2

- 4% was eliminated in

the feces at the low dose versus 17

- 22% at the high dose. Half

- lives of elimination are approximately 20 hours for the low dose groups and 33

- 48 hours for the high dose group. Radioactivity in the blood peaked at 2 to 4 hours at the low and high dose respectively

.

Difenoconazole undergoes successive oxidation and conjugation reactions. Following administration of 300 mg/kg of ( 14 C

- phenyl) difenoconazole

, three major urinary metabolites

were identified as CGA 205375 and HO

- CGA 205375 (6% of dose ), sulfate conjugates (and their isomers) of H O

- 205375 (3.9% of dose ) , and the hydroxyacetic metabolite of H O

- CGA

20537 5 (2.0% of dose )

. N o single unknown urinary metabol ite accounted for >1.1% of the dose.

Free triazole metabolite was detected in the urine of the triazole

- label groups and its byproduct was detected in the liver of phenyl labeled groups only.

The study results indicate that difenoconazole and/or its meta bolites do not bioaccumulate appreciably following oral exposure since all tissues contained negli gib le levels (<1%) or radioactivity 7 days post exposure.

A dermal absorption factor of 6% was derived based on data from a triple pack of a 28 rat

in vivo dermal absorption study and in vitro dermal absorption studies conducted with rat and human skin. Inhalation toxicity is assumed to be equivalent to oral toxicity.

4.3 Toxicological Effects

Subchronic and chronic studies with difenoconazole in mice and rats showed decreased body weights, decreased body weight gains and effects on the liver (e.g. hepatocellular hypertrophy, liver necrosis, fatty changes in the liver )

. In an acute neurotoxicity study in rats,

reduced fore

- limb grip strength was observ ed on day 1 in males and clinical signs of neurotoxicity were observed in females at the limit dose of 2000 mg/kg. In a subchronicPage 14 of 70

neurotoxicity study in rats, decreased hind limb strength was observed in males only at the mid

and high

- dose s

. However, t he effects observed in acute and subchronic neurotoxicity studies are transient , and the dose

- response is well characterized with identified no observed adverse effect levels ( NOAELs )

. No s ystemic toxicity was observed at the limit dose in the most recent ly

submitted 28

- day rat dermal toxicity study.

The available toxicity studies indicated no increased susceptibility of rats or rabbits from

in utero or postnatal exposure to difenoconazole. In prenatal developmental toxicity studies in

rats and rabbits and in the two

- generation reproduction study in rats, fetal/offspring toxicity, when observed, occurred at equivalent or higher doses than in the maternal/parental animals.

There are no indications in the available studies that organs associated with immune

function

, such as the thymus and spleen, are affected by difenoconazole

. An immunotoxicity study, required under Part 158 Toxicology Data requirements, has been submitted and is under

review.

In accordance with HED’s current policy and EPA’s 200 5 Cancer Guidelines, difenoconazole is classified as “Suggestive Evidence of Carcinogenic Potential” based on liver tumors observed in mice at 300 ppm and higher, the absence of tumors at two lower doses of 10 and 30 ppm, excessive toxicity observed at the two highest doses of 2500 and 4500 ppm, the absence of genotoxic and no evidence of carcinogenicity in rats. HED’s Cancer Peer Review

Committee recommended use of an MOE approach to risk assessment using the chronic point of departure (POD) based on effe cts observed in the chronic mouse study relevant to tumor development ( i.e. , hepatocellular hypertrophy, liver necrosis, fatty changes in the liver and bile stasis). The POD is considered protective of the cancer effects.

Difenoconazole possesses low a cute toxicity by the oral, dermal and inhalation routes of exposure. It is not an eye or skin irritant and is not a sensitizer.

The toxicity profiles for difenoconazole are provided in Appendix A.

4

. 4 Safety Factor for Infants and Children (FQPA Safety Factor)

The FQPA factor for increased susceptibility to infant s and children is reduced to 1x based on the following considerations. Further discussion may be found in the following

sections.

- The t oxicology data base for difenoconazole is complete and adequate for assessing

incre ased susceptibility under FQPA.

- There is no indication of increased susceptibility of rats or rabbit fetuses to in utero and/or postnatal exposure in the developmental and r eproductive toxicity data.

- T here are no residual uncertainties in the exposure database.

- The dietary risk assessment is conservative and will not underestimate dietary exposure

to difenoconazole.Page 15 of 70

4.4.1 Completeness of the Toxicology Database

The toxicity database is sufficient for a full hazard evaluation and is considered adequate to evaluate risks to infants and children. Acceptable acute and subchronic neurotoxicity studies

are availab le. An immunotoxicity study required under new 40 CFR Part 158 data requirements for registration of a pesticide (food and non

- food uses) has been submitted and is under review

. The Hazard and Science Policy Council ( HASPOC ) concluded based on a weight of evidence ( WOE) approach that a 28

- day inhalation toxi city study is not required at this time. This approach considered all of the available hazard and exposure information for difenoconazole, including: (1) the use of an oral POD that results in MOEs greater than 1,300 (the lowest MOE)

for risk via the inhal ation route resulting from occupational and residential; (2) the physical/chemical properties and very low vapor pressure of difenoconazole; and (3) the toxicological profile of difenoconazole.

4.4.2 Evidence of Neurotoxicity

In an acute neurotoxicity study in rats, reduced fore

- limb grip strength was observed on day 1 in males . C linical signs of neurotoxicity were observed in females at the limit dose of 2000 mg/kg. The effect in males is considered transient since it was not observed at later

observation points . T oxicity in females was observed only at the limit dose. In a subchronic neurotoxicity study in rats decreased hind limb strength was observed in males only

. The effects observed in acute and subchronic neurotoxicity studies are transient , and the dose

- response is

well characterized with identified NOAELs. Based on the toxicity profile, and lack of concern for neurotoxicity, a developmental neurotoxicity study in rats is not required.

4.4.3 Evidence of Sensitivity/Susceptibility in the Developing or Young Animal

The available Agency Guideline studies indicated no increased susceptibility of rats or rabbits to in utero and/or postnatal exposure to difenoconazole. In the prenatal developmental toxicity studies in rats and rabbits and the two

- generat ion reproduction study in rats, toxicity to the fetuses/offspring, when observed, occurred at equivalent or higher doses than in the maternal/parental animals.

In a rat developmental toxicity study developmental effects were observed at doses higher th an those which caused maternal toxicity. Developmental effects in the rat included increased incidence ossification of the thoracic vertebrae and hyoid, decrease d number of sternal

centers of ossification , increased number of ribs and thoracic vertebrae

, and decrease d number of

lumbar vertebrae . In the rabbit study, developmental effects (increases in post

- implantation loss and resorptions and decreases in fetal body weight) were also seen at maternally toxic doses. In

the two

- generation reproduction st udy in rats, toxicity to the fetuses/offspring, when observed, occurred at equivalent or higher doses than in the maternal/parental animals.Page 16 of 70

4

. 4

. 4 Residual Uncertainty in the Exposure Database

T here are no residual uncertainties in the exposure database. The dietary risk assessment

is conservative and will not underestimate dietary exposure to difenoconazole.

4

. 5 Toxicity Endpoint and Point of Departure

4.5.1 Dose

- Response Assessment

Toxicity endpoints and points of departure (PODs) for dietary (food and water),

o ccupational, and residential exposure scenarios are summarized below. A detailed description of the studies used as a basis for the selected endpoints are presented in Append ix A.

An acute POD of 25 mg/kg/day (NOAEL) was selected from an acute neurotoxicity study in rats based on reduced fore

- limb grip strength in males on day 1 at the LOAEL of 200 mg/kg/day

. An uncertainty factor (UF) of 100x (10x to account for interspec ies extrapolation and 10x for intraspecies variation) was applied to the NOAEL to obtain an acute reference dose ( aRfD ) of 1.0 mg/kg/day. Since the FQPA factor has been reduced to 1X, the acute population adjusted dose ( a PAD) is equivalent to the a RfD. T he selected e ndpoint is considered appropriate for acute dietary exposure because effects were seen after a single dose. The endpoint is protective of the general population and all subpopulations for effects seen in the acute neurotoxicity study in rats. It is also protective of developmental and maternal effects observed in the rabbit developmental toxicity study at the LOAEL of 75 mg/kg/day and NOAEL of 25 mg/kg/day.

A chronic POD of 0.96 mg/kg/day (NOAEL) was selected from a chronic/oncogenicity

oral study in rats based on cumulative decreases in body weight gains in males observed at the LOAEL of 24 mg/kg/day. A UF of 100x (10x to account for interspecies extrapolation and 10x for intraspecies variation) was applied to the dose to obtain a chronic reference dose (cRfD /cPAD ) of 0.0 1 mg/kg/day.

S hort

- term incidental oral and short

- and intermediate term dermal and inhalation POD s of 1.25 mg/kg/day were selected from a two generation reproduction study in rats based on decreased pup weight in males at 12.5 mg/kg/day (LOAEL) on day 21 , and reductions in body weight gain in F0 females. Although dermal toxicity studies are available, a POD from an oral study was selected because effects in young animals (decreased pup weight) the primary effe ct of concern for short, intermediate and long term exposure is not specifically evaluated in the available dermal toxicity studies that only assess adult animals. The selected endpoint is protective of offspring effects from dermal exposure. An MOE 100 is required for the short

and intermediate

- term dermal and inhalation exposure scenarios based on the conventional uncertainty factor of 100 ( 10x for interspecies extrapolation and 10x for intraspecies variation )

. There are no residential uses for difen oconazole that would result in incidental oral exposure to
children.

A dermal absorption factor (DAF) is applied when dermal exposure endpoints are selected from oral toxicity studies. The dermal factor converts the oral dose to an equivalentPage 17 of 70

dermal d ose for the risk assessment. A DAF of 6% was selected for use in risk assessment based on available in vivo dermal absorption studies in rat and in vitro dermal absorption studies

conducted with rat and human skin. Further discussion of the dermal absorp tion may be found in

Attachment A.3

.

4.5.2 Recommendations for Combining Exposure Routes

When there are potential residential exposures to the pesticide, aggregate risk assessment must consider exposures from three major sources: oral, dermal and inhalation exposures. Oral,

d ermal and inhalation exposures to residents should be aggregated for difenoconazole because

the endpoints selected for these exposure routes are based on common toxicological effects.

4

. 5.3 Classification of Carcinogenic Potential

Difenoconazole is not mutagenic, and no evidence of carcinogenicity was seen in rats.

E vidence for carcinogenicity was seen in mice, where liver tumors were induced at doses which were considered to be excessively high for carcinogenicity testing. Liver tumors were observed in mice at 300 ppm and higher; however, based on excessive toxicity observed at the two highest doses of 2500 and 4500 ppm (females terminated after two weeks due to excessive toxicity resulting in moribundity and death), the absence of tumors at two lower doses of 10 and 30 ppm

, t he absence of genotoxic effects

, and no e vidence of carcinogenicity in rats. In accordance with

HED’s current policy and EPA’s 2005 Cancer Guidelines, difenoconazole is classified as “Suggestive Evidence of Carcinogenic Potential,” b ased on excessive toxicity observed at the two highest doses, t he absence of tumors at the lower doses and the absence of genotoxic effects

. Based on the CPRC recommendation, the risk assessment uses an (MOE) approach utilizing the

no

- observable

- adverse

- effects

- level (NOAEL) of 30 ppm ( 4.7 and 5.6 mg/kg/day in males and females, respectively) and the lowest

- observable

- adverse

- effects

- level (LOAEL) of 300 ppm ( 46

and 58 mg/kg/day in males and females, respectively) from the mouse study using only those biological endpoints which were relevant to tumor development ( i.e. , hepatocellular hypertrophy, liver necrosis, fatty change s in the liver and bile stasis). The chronic POD of 0.96 mg/kg/day selected based on bodyweight effects is protective of the cancer effects.

4

. 5.4 Summary of Points of Departure Used in Risk Assessment

Toxicological doses/endpoints selected for the difenoconazole risk ass essment are provided in Tables 4 and 5

.Page 18 of 70

Table 4 . Summary of Toxicological Doses and Endpoints for Difenoconazole for Use in Dietary and Non

- Occupational

Human Health Risk Assessments

Exposure

Scenario Point of

Departure Uncertainty/FQPA

Safety Factors RfD, PAD, LOC

for Risk

Assessment Study and Relevant Toxicological

Effects

Acute Dietary (All populations) NOAEL = 25

mg/kg UF A = 10X

UF H = 10X

UF FQPA = 1X aRfD = aPAD =

0.25 mg/kg/day Acute Neurotoxicity Study in Rats

LOAEL= 200 mg/kg in males based

on reduced fore

- limb grip strength in males on day 1. Chronic Dietary (All populations) NOAEL = 0.96

mg/kg/day UF A = 10X

UF H = 10X

UF FQPA = 1X cRfD = cPAD =

0.01mg/kg/day Combined chronic

toxicity/carcinogenicity (rat; dietary)

LOAEL = 24.1 /32.8 mg/kg/day (M/F) based on cumulative decreases in body

- weight gains.

Incidental Oral

Short

- Term (1

- 30 days) Oral NOAEL =

1.25 mg/kg/day UF A = 10X

UF H = 10X

UF FQPA = 1X Residential LOC

for MOE<100 Reproduction and fertility Study (rat;

dietary) Parental/ Offspring LOAEL = 12.5 mg/kg/day based on decreased pup weight in males on day 21 and reduction in body

- weight gain of F 0 females prior to mating, gestation

and la ctation.

Dermal

Short

- and

Intermediate

- Term (1

- 30 days and 1

- 6 months)

DAF = 6% Oral NOAEL =

1.25 mg/kg/day UF A = 10X

UF H = 10X

UF FQPA = 1X Residential LOC

for MOE<100 Reproduction and fertility Study (rat;

dietary) Parental/ Offspring LOAEL

= 12.5 mg/kg/day based on decreased pup weight in males on day 21 and reduction in body

- weight gain of F 0 females prior to mating, gestation

and lactation.

Inhalation (Short

- and

Intermediate

- term)

Inhalation and oral absorption assumed equivalent Oral NOAEL =

1 .25 mg/kg/day UF A = 10X

UF H = 10X

UF FQPA = 1X Residential LOC

for MOE<100 Reproduction and fertility Study (rat;

dietary) Parental/ Offspring LOAEL = 12.5 mg/kg/day based on decreased pup weight in males on day 21 and reduction in body

- weight gain of F 0 females prior to mating, gestation

and lactation. Cancer (oral, dermal, inhalation) Difenoconazole is classified “ Suggestive Evidence of Carcinogenic Potential” with a non

- linear (MOE)

approach for human risk characterization (CPRC Document, 7/27/94, Memo, P. V. Shah dated March 3, 2007, HED Doc. No. 0054532).
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose

- response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL = no observed adverse effect level. LOAEL = lowest observed adverse effect level. UF = uncertainty factor. UF A = extrapolation from animal to human (interspecies). UF H = potential variation in sens itivity among members of the human population (intraspecies DAF = Dermal Absorption FactorPage 19 of 70

Table 5 . Summary of Toxicological Doses and Endpoints for Difenoconazole for Use Occupational Human Health Risk

Assessments Exposure

Scenario Point of

Departure Uncertainty/FQPA

Safety Factors RfD, PAD, Level of

Concern for Risk

Assessment Study and Toxicological Effects

Dermal

Short

- and

Intermediate

- Term (1

- 30 days and 1

- 6 months)

DAF = 6% Oral NOAEL

= 1.25 mg/kg/day UF A = 10X

UF H = 10X Occupational LOC for

MOE<100 Reproduction and fertility Study (rat; dietary) Parental/ Offspring LOAEL = 12.5 mg/kg/day based on decreased pup weight in males on day 21 and reduction in body

- weight gain of F 0 females prior to mating, gestation

and lactation

. Inhalation (Short

- and

Intermediate

- term)

Inhalation and oral absorption assumed equivalent Oral NOAEL

= 1.25 mg/kg/day UF A = 10X

UF H = 10X Occupational LOC for

MOE<100 Reproduction and fertility Study (rat; dietary) Parental/ Offspring LOAEL

= 12.5 mg/kg/day based on decreased pup weight in males on day 21 and reduction in body

- weight gain of F 0 females prior to mating, gestation

and lactation. Cancer (oral, dermal, inhalation) Difenoconazole is classified “ Suggestive Evidence of Carcinogenic Potential” with a non

- linear (MOE)

approach for human risk characterization (CPRC Document, 7/27/94, Memo, P. V. Shah dated March 3, 2007, HED Doc. No. 0054532).
Point of Departure (POD) = A data point or an estimated point that is derived from observed dose

- response data and used to mark the beginning of extrapolation to determine risk associated with lower environmentally relevant human exposures. NOAEL

= no observed adverse effect level. LOAEL = lowest observed adverse effec t 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). FQPA SF = FQPA Safety Factor. PAD = population adjusted dose (a = acute, c = chronic). RfD = reference dose. MOE = margin of exposure. LOC = level of concern. N/A = not applicable.

5 .0 DIETARY AND DRINKING WATER EXPOSURE AND RISK ASSESSMENT

5 .1 Metabolite/Degradate Residue Profile

5.1.1 Summary of Plant and Animal Metabolism Studies

The nature of the residue in plants is understood based on acceptable plant metabolism studies reflecting foliar applications in canola, grape, potato, tomato, and wheat, and seed

treatment in wheat. HED concludes that the residue of concern for both tole rance enforcement and risk assessment for crops included in this petition is difenoconazole per se . The nature of the residue in livestock is understood based on acceptable goat and hen metabolism studies. The

residues of concern for both tolerance setti ng and risk assessment for livestock commodities are

difenoconazole per se and its metabolite CGA

- 205375. In addition, metabolite OH

- CGA

169374, which comprised 15% of the TRR in goat milk from the phenyl

- labeled study, should be

considered as a residue o f concern for the dietary risk assessment.

The nature of the residue in rotational crops is adequately understood. The metabolism

of difenoconazole in rotat ional crops is similar to that of primary crops. The available

difenoconazole confined and limi ted field rotational crop trials are deemed adequate to satisfy data requirements under Guidelines 860.1850 and 860.1900. Taken together, these data support

a 30

- day plantback interval (PBI) for cereal and root/tuber crops not already registered for foli ar use with difenoconazole and a 60

- day PBI for all other crops not already registered for foliar usePage 20 of 70

with difenoconazole. With these PBIs, tolerances for residues of difenoconazole are not needed for rotational crops.

5.1. 2 Comparison of Metabolic Pa thways

Little information is available on the toxici ty of the major difenoconazole metabolite s. The CGA

- 205375 metabolite formed in livestock appears to be formed in the rat also and is, therefore, part of the total toxic exposure for these animals.

5.1.3 Residues of Concern Summary and Rationale

Residues of concern were determined based on recommendations from the HED Residues of Concern Knowledgebase Sub

- committee (ROCKS) (D391350, 9/19/11)

. The residue of concern for plant commodities for tolerance ex pression and risk assessment purposes

is difenoconazole per se

. The HED ROCKS has determined that the parent compound and the

CGA

- 205375 metabolite are the residues of concern in livestock commodities for both the tolerance expression and the risk assessm ent. In addition, metabolite OH

- CGA

- 169374, which comprised 15% of the TRR in goat milk from the phenyl

- labeled study, should be considered as a residue of concern for the dietary risk assessment. Based on available goat metabolism data,

total residues of concern in milk for dietary risk assessments (parent, CGA

- 205375, and OH

CGA

- 169374), should be calculated by multiplying the tolerance in milk by a factor of 1.5x.

Table 6 summarizes tolerance expression and the residues of concern in plant and livestoc k

commodities.

Table 6 . Difenoconazole Residues of Concern in Plants and Ruminants.

Matrix Residues of Concern

For Risk Assessment For Tolerance Expression

Plants Primary and Rotational crops Parent Only Parent Only

Livestock Ruminant and Poultry Parent and CGA 205375 Parent and CGA 205375

Milk Parent, CGA 205375 and

OH

- CGA

- 169374 Parent and CGA 205375

Drinking Water Parent and CGA 205375 NA

Note: The triazole

- containing metabolites 1,2,4

- T, TA, and TAA should be included in the residues of concern for risk assessment purposes only for plant and livestock commodities. Since these metabolites are common to the entire class of

traizole

- derivative fungicides and because of differential toxicity between metabolites and the various parent compoun ds, risks associated with exposure to 1,2,4

- T and to TA/TAA are addressed separately.

5.2 Food Residue Profile

5.2.1 Residue s in Crops

The submitted postharvest potato magnitude of the residue data, conducted with a 3.0 lb/gal flowable suspension (FS) formulation of difenoconazole adequately reflect the proposed use pattern for potato postharvest. Provided the use is expanded to all tuber and corm vegetables listed under subgroup 1C, for which potato is the representati ve commodity, these data will support a tolerance of 4.0 ppm in/on Vegetables, tuberous and corm, subgroup 1C.Page 21 of 70

Previously submitted field trial data are adequate to support the proposed amended uses. It is important to note that the proposed amendmen ts to existing labels are limited to expansions to add the commodities specified under the new crop groups/subgroups and do not include substantive changes to currently registered use patterns (i.e., maximum use rates, retreatment intervals, preharvest int ervals, use of adjuvants, etc.). The proposed tolerances in/on F ruiting Vegetables Group 8

- 10 (0.6 ppm); Citrus Fruits Group 10

- 10 (0.6 ppm), Pome Fruits Group 11

- 10 (1.0 ppm), and Low growing Berry Subgroup 13

- 07G, Except Cranberry (2.5 ppm) are appropri ate.

5.2.2 Residue in Livestock and Poultry

There are no new livestock feedstuffs associated with the proposed uses since difenoconazole is already registered for foliar uses on potatoes, citrus fruits, and pome fruits. However, due to the proposed postharvest use on potatoes, difenoconazole residue estimate s in/on potato culls and potato processing waste, which are beef and dairy feedstuffs, have increased substantially. Potato culls and potato processing waste are both carbohydrate concentrates which are sometimes used in cattle feeding and considered alte rnative feedstuffs. There are no poultry or swine feedstuffs associated with the proposed uses. Adequate cattle and poultry feeding studies are available for difenoconazole

.

The dietary burdens for beef and dairy cattle are recalculated for this Sect ion 3 action. In accordance with ChemSAC recommendations concerning blended commodities (ChemSAC meeting minutes 12/21/11), the difenoconazole residue estimate in/on potato processing waste for livestock MRBD calculations (3.5 ppm) was based on the median residue value for potato reflecting the proposed post harvest use (1.13 ppm) and the average concentration factor for potato wet peel (3.1x). Potato processing waste replaces AGF and wet apple pomace as the major contributors to the MRBDs of cattle for d ifenoconazole. The MRBDs are recalculated to be: 7.4 ppm for beef cattle and 2.8 ppm for dairy cattle. Based on the re calculated dietary burdens and the feeding study data, HED concludes that the currently established tolerances for milk, meat, fat, me at byproducts (except liver) and liver a re adequate to support the proposed

uses

.

5. 2.3 Residue s in Processed Commodities

Adequate processing data for potato were submitted with the petition. The potato processing data indicate that residues of difenoc onazole do not concentrate in flakes and chips but do concentrate in wet peel. Based on the HAFT for residues in/on potatoes postharvest (2.34 ppm) and the average processing factor for potato wet peel (3.1x), expected residues of

difenoconazole from the proposed postharvest use on potato would be 7.3 ppm in potato, peel, wet. The proposed removal of the currently established tolerance for residues of difenoconazole on potato, processed waste is not appropriate; a tolerance is needed for residues of

difen oconazole in potato, peel, wet at 7.3 ppm. Apple, tomato, and orange processing data were previously submitted and are adequate to support the proposed uses. No changes to the currently established tolerances in apple, wet pomace (4.5 ppm), citrus, drie d pulp (2.0 ppm), and citrus oil (25 ppm) are needed.Page 22 of 70

5. 3 Water Residue Profile

The drinking water estimates used in the dietary risk assessment were provided by the

Environmental Fate and Effects Division. EFED conducted a Tier II drinking water assessment for surface water sources using the Pesticide Root Zone/Exposure Analysis Modeling System (PRZM/ EXAMS ) for the registered and proposed new uses. Among the registered and proposed new uses, the highest estimated drinking water concentrations (E DWCs) for surface water sources were derived for aerial applications of difenoconazole to New York grapes at the maximum annual application rate of 0.46 lb ai/acre The estimated drinking water residues for 1

- in

- 10 year annual peak, 1

- in

- 10 year annual mean , and 36

- year annual mean are 17.4, 11.8, and 8.6 μg/L (ppb) respectively. The highest S creening C oncentration I n GRO und W ater ( SCI

GROW) estimated drinking water concentration of difenoconazole from sh allow ground water

sources is 1.28 x 10 - 2 μg/L

, obtai ned for the maximum application rate for ornamentals (0.52 lb ai/A) . These concentrations can be considered as both the acute and chronic groundwater values. The EDWCs from ground water sources are expected to be the same for the proposed golf course

tur f uses as estimated for ornamentals. The 1

- in

- 10 year annual peak EDWC of 17.4 μg/L (ppb) was used for the acute dietary (food plus water) exposure analysis and the 1

- in

- 10 year annual mean EDWC of 11.8 μg/L (ppb) was used for the chronic dietary (food p lus water) exposure analysis.

5. 4 Dietary and Drinking Water Exposure and Risk

Screening level acute and refined chronic dietary and drinking water exposure and risk assessments were conducted using the Dietary Exposure Evaluation Model with the Food Commodity Intake Database (DEEM

- FCIDTM). Dietary risk assessment incorporates both exposure and toxicity of a given pesticide. For acute and chronic dietary assessments, the risk is expressed as a percentage of a maximum acceptable dose (i.e., the dose w hich HED has concluded will result in no unreasonable adverse health effects). This dose is referred to as the population adjusted dose (PAD). The PAD is equivalent to the POD divided by the uncertainty

factors

. For acute and non

- cancer chronic exposure s, HED is concerned when estimated dietary

risk exceeds 100% of the PAD.

5.4 .1 Acute Dietary Risk Assessment

The un refined acute analysis for food and water as sumed tolerance

- level residues, 100% crop treated (CT), and the available empirical or DEEM (ver. 7.81) default processing factors. The resulting acute food plus water exposure estimates were less than HED’s level of concern (

- <100% of the acute population

- adjusted dose (aPAD)) at the 95 th percentile of the exposure distribution for the general U.S. population (12 % aPAD) and all population sub

- groups; the most highly exposed population subgroup was children1

- 2 years old with 27 % aPAD.Page 23 of 70

Table 7 . Summary of Acute Dietary Exposure (Food and Drinking Water) and Risk for Difenoconazole at

the 95 th Percentile.

Population Subgroup aPAD (mg/kg/day) Exposure (mg/kg/day) %aPAD

General U.S. Population

0.25 0.030385 12

All Infants (< 1 year old) 0.056767 23

Children 1

- 2 years old 0.066505 27

Children 3

- 5 years old 0.053081 21

Children 6

- 12 years old 0.034395 14

Youth 13

- 19 years old 0.023787 10

Adults 20

- 49 years old 0.022687 9

Adults 50+ years old 0.025302 10

Females 13

- 49 years old 0.022729 9

5.4.2 Chronic Dietary Risk Assessment

The somewhat refined chronic analysis for food and water assumed tolerance

- level residues for some commodities, average field trial residues for the majority of commodities, the available empirical or DEEM (ver. 7. 81) default processing factors, and 100 % CT. The resulting chronic food plus water exposure estimates were less than HED’s level of concern (

- <100% of the chronic population

- adjusted dose (cPAD)) for the general U.S. population (30 % cPAD) and all popula tion sub

- groups; the most highly exposed population subgroup was

children 1

- 2 years old with 75 % cPAD.

Table 8 . Summary of Chronic Dietary (Food and Drinking Water) Exposure and Risk for Difenoconazole.

Population Subgroup cPAD (mg/kg/day) Exposure (mg/kg/day) %cPAD

General U.S. Population

0.01 0.002987 30

All Infants (< 1 year old) 0.004701 47

Children 1

- 2 years old 0.007460 75

Children 3

- 5 years old 0.006242 62

Children 6

- 12 years old 0.003903 39

Youth 13

- 19 years old 0.002574 26

Adults 20

- 49 years old 0.002382 24

Adults 50+ years old 0.002594 26

Females 13

- 49 years old 0.002304 23

Dietary Assessment of Free Triazole and its Conjugates

Reference: Common Triazole Metabolites: Updated Dietary (Food + Water) Exposure and Risk Assessment to

Address The Amended Propiconazole Section 3 Registration to Add Uses on Snap beans, succulent shelled beans, dry beans, tomato (post

- harvest, citrus (post

- harvest) , and stone fruit (post

- harvest); The Amended Difenoconazole Section 3 Registration to Add Use on Root and Tuber group 1C; and the Amended Flutriafol Section 3 Registration

to Add Use on Field Corn. T. Morton , DP397591. drs, 1 / 26 /1 2

.Page 24 of 70

T he proposed Section 3 use s of propiconazole result s in an increase in dietary exposure estimates for free triazole or conjugated triazoles. Therefore, the last dietary exposure analyses for the triazole

metabolites need ed to be updated. The proposed Section 3 uses of difenoconazole results in dietary risk estimates below HED’s level of concern; see Table 9.

Table 9 . Summary of Dietary (Food and Drinking Water) Exposure and Risk for the Common Triazole Metabolites Adding the new Section 3 Uses for Propiconazole, Flutr iafol, and Difenoconazole.

Population Subgroup Acute Dietary ( 95 th Percentile) Chronic Dietary Cancer

Dietary Exposure (mg/kg/day) % aPAD* Dietary Exposure (mg/kg/day) % cPAD* Dietary Exposure (mg/kg/day) Risk

1,2,4

- Triazole General U.S. Population 0.00 8892 30 0.001 409 2 8

Not Applicable Not

Applicable All Infants (< 1 year old) 0.01 2475 42 0.00 1923 39

Children 1

- 2 years old 0.0 23049 77 0.00 3723 75

Children 3

- 5 years old 0.01 7674 59 0.002 994 60

Children 6

- 12 years old 0.0 11632 39 0.001 891 3 8

Youth 13

- 19 years old 0.00 8196 27 0.001 266 2 5

Adults 20

- 49 years old 0.00 6959 23 0.00 1162 2 3 Adults 50+ years old 0.00 6050 20 0.00 1097 22

Females 13

- 49 years old 0.00 7007 23 0.00 1166 23 Triazolylalanine + Triazolylacetic Acid

General U.S. Population

Not Applicable Not

Applicable 0.01 9824 22

Not Applicable Not

Applicable All Infants (< 1 year old) 0.0 20308 2 3

Children 1

- 2 years old 0.0 56263 63

Children 3

- 5 years old 0.0 45007 50

Children 6

- 12 years old 0.0 28078 31

Youth 13

- 19 years old 0.01 8635 21

Adults 20

- 49 years old 0.01 5881 1 8 Adults 50+ years old 0.0 14719 1 6

Females 13

- 49 years old 0.0 86155 86 0.01 6036 1 8 * The values for the highest exposed population for each type of risk assessment are bolded.

6.0 RESIDENTIAL EXPOSURE AND RISK

A new residential exposure assessment is not required for the proposed amended/new

use s because there are no homeowner uses or application to residential areas associated with

the se use s

. However, difenoconazole is register ed on ornamentals and golf coarse turf which will result in residential exposure. Therefore, theses residential uses were aggregated with the recent dietary exposure.

6.1 Residential Bystander Post A pplication Inhalation Exposure

Based on the Agency's current practices, a quantitative residential bystander postapplication inhalation exposure assessment was not performed for difenoconazole at this time. However, volatilization of pesticides may be a potential source of postapplication inhalation exposur e to individuals nearby to pesticide applications. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide,Page 25 of 70

Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009. The Agency received the SAP’s final report on March 2, 2010 ( http://www.epa.gov/scipoly/SAP/meetings/2009/120109meeting.html ). The Agency is in the process of evaluating the SAP report and may, as appropriate, develop policies and procedures, to identify the need for and, subsequently, the way to incorporate postapplication inhalation exposure into the Agency's risk assessments. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative postapplication inhalation exposure assessment
for difenoconazole

.

6.2 Spray Drift

Spray drift is always a potential source of exposure to residents nearby to spraying operations. This is particularly the case with aerial application, but, to a lesser extent, could also be a potential source of exposure from the ground application metho d employed for

difenoconazole . The Agency has been working with the Spray Drift Task Force, EPA Regional Offices and State Lead Agencies for pesticide regulation and other parties to develop the best spray drift management practices (see the Agency’s Spra y Drift website for more information at http://www.epa.gov/opp00001/factsheets/spraydrift.htm). On a chemical by chemical basis, the Agency is now requiring interim mitigation measures for aerial applications that must be placed on product labels/labeling . The Agency has completed its evaluation of the new database submitted by the Spray Drift Task Force, a membership of U.S. pesticide registrants, and is developing a policy on how to appropriately apply the data and the AgDRIFT computer model to

its risk assessments for pesticides applied by air, orchard airblast and ground hydraulic methods. After the policy is in place, the Agency may impose further refinements in spray drift management practices to reduce off

- target drift with specific products with s ignificant risks

associated with drift.

7.0 AGGREGATE EXPOSURE AND RISK ASSESSMENT

In accordance with the FQPA, when there are potential residential exposures to a pesticide, aggregate risk assessment must consider exposures from three major routes: oral, dermal, and inhalation. There are three sources for these types of exposures: food, drinking water, and reside ntial uses. In an aggregate assessment, risks from rele vant sources are added together and compared to a level of concern. Since a common effect has been identified for

assessment of short

- term oral, dermal, and inhalation exposures (changes in body weig hts and body

- weight gains) for difenoconazole, the short

- term aggregate risk assessment combines exposure from food, water, and residential sources. Only short

- term residential exposures are expected based on current use patterns. T he acute and chronic e xposure estimates from the dietary exposure analyses represent aggregate risk for acute and chronic exposures.

Difenoconazole is currently registered for the following uses that could result in residential exposures: Ornamentals. EPA assessed residential exposure using the following assumptions: Adults may be exposed to difenoconazole from its currently registered use on ornamentals. Residential pesticide handlers may be exposed to short

- term duration (1

- 30 days) only. The dermal and inhalation (short

- term) residential exposure was assessed for "homeowners" mixer/loader/applicator wearing short pants and short

- sleeved shirts as well asPage 26 of 70

shoes plus socks using garden hose

- end sprayer, “pump

- up” compressed air sprayer, and backpack sprayer. Residential p ost

- application exposure may occur from use of difenoconozole on golf course turf. Short

- term dermal exposure was assessed for post

- application exposure to golf course turf. Further information regarding EPA standard assumptions and generic inputs for

re sidential exposures may be found at http://www.epa.gov/pesticides/trac/science/trac6a05.pdf

.

7. 1 Short

- Term Aggregate Risk to Residential Applicators

Short term aggregate exposure takes into account residential exposure plus average exposure levels to food and water (considered to be a background exposure level). The short term aggregate risk for residential handlers is the estimated risk associated with combined risks from average food and drinking water exposures and dermal and inhalation exposures to adult applicators. Short term aggregate risk estimates for re sidential handlers are provided in Table 10 aggregates the short

- term risk for adults fr om residential handler exposure and average food and water exposure (as a background). The lowest aggregate MOE is 200 , which is greater than the target MOE of 100 and therefore not of concern

.

Table 10 : Estimated Difenoconazole Short

- term Aggregate Risk to Adults from Residential Handler Activities

Exposure Scenario Target
MOE 1 Route of

Exposure Daily dose

mg/kg/day NOAELs

mg/kg/day MOE at Day 0 Combined MOE 4

Average Food and Water

(As background) N/A Food and

water 0.002958

1.25 4 20 2 NA

Hose End Sprayer

- Ornamentals

100 Dermal and

Inhalation 0.0022 575 3 240

Handheld Pump Spray

- Ornamentals 0.0031 400 200

Hose End Sprayer

– Flower

Gardens 0.0019 660 260

Handheld Pump Spray

– Flower Gardens 0.0021 590 250

1 Target MOE= 100, Developmental rat

- increased incidence of rudimentary risks. NOAEL = 0.96

2 MOE food and water = [(short

- term oral NOAEL)/(chronic dietary exposure)]

3 MOE dermal and inhalation = [(short

- term NOAEL (1.25 )/(high

- end inhalation and dermal residential exposure)]

4 Aggregate Combined MOE (food, water, and residential) = 1÷ [(1÷MOE food and water) + (1÷MOE handler inhalation and dermal)].

7.2 Short

- Term Aggregate Risk for Residential Post

- Application Exposure

Table 1 1 aggregates the short

- term risk for adults from residential post application, and

average food and water exposure

. The highest post application exposure from residential use on turf was used in the short term aggregate. The aggregate MOE is 600 , which is greater than the target MOE of 100. This aggregate exposure assessment is considered very conservative

because the assumptions used for each of the scenarios separately are already high end (i.e., time spent outdoors, dislodgeable residues).Page 27 of 70

Table 1 1 : Estimated Difenoconazole Short

- term Aggregate Risk from Residential Post

- Application Activities

Exposure Scenario Target

MOE 1 Route of Exposure Daily D ose

mg/kg/day NOAELs MOE at Day

0 Combined

MOE 4

Average Food and Water

Adult N/A Food and

water 0.002958 1.25 420 2 NA

Adult Golfer 100 Dermal 0.00024 5200 3 390

1 Target MOE= 100, Developmental rat

- increased incidence of rudimentary risks. NOAEL = 0.96

2 MOE food and water = [(short

- term oral NOAEL)/(chronic dietary exposure)]

3 MOE dermal = [(short

- term dermal NOAEL)/(high

- end dermal residential exposure)]

4 Aggregate Combined MOE (food, water, and residential) = 1÷ [(1÷MOE food and water) + (1÷MOE post appl. dermal)].

Updated Aggregate Assessment of Free Triazole & its Conjugates

Reference: Common Triazole Metabolites: Updated Aggregate Human Health Risk Assessment to Address Tolerance Petitions for Propiconazole, Difenoconazole, and Flutriafol . DP 397592 , T. Morton, 1 / 26 /1 2

.

The addition of the new proposed uses increase the aggregate expos ure to free triazoles and its conjugates. Therefore, the aggregate human health risk assessment for free triazoles and its conjugates was updated and the aggregate estimates are below HED’s level of concern ( DP3 97592 , T. Morton, 1 / 26 /1 2).

8 .0 CUMULATIVE RISK

Difenoconazole is a member of the triazole

- containing class of pesticides. Although conazoles act similarly in plants (fungi) by inhibiting ergosterol biosynthesis, there is not necessarily a relationship between their pesticidal activity and their mechanism of toxicity in mammals. Structural similarities do not constitute a common mechanism of toxicity. Evidence is needed to establish that the chemicals operate by the same, or essentially the same, sequence of major biochemical events (EPA, 2002). In conazoles, however, a variable pattern of toxicological responses is found ; s ome are hepatotoxic and hepatocarcinogenic in mice. Some induce thyroid tumors in rats. Some induce developmental, reproductive, and neurological effects in rodents.

Furth ermore, the conazoles produce a diverse range of biochemical events including altered cholesterol levels, stress responses, and altered DNA methylation. It is not clearly understood whether these biochemical events are directly connected to their toxicolo gical outcomes. Thus, there is currently no evidence to indicate that conazoles share common mechanisms of toxicity and EPA is not following a cumulative risk approach based on a common mechanism of toxicity for the conazoles. For information regarding E PA’s procedures for cumulating effects from substances found to have a common mechanism of toxicity, see EPA’s website at http://www.epa.gov/pesticides/cumulative

.

Difenoconazole is a triazole

- derived pesticide. This class of compounds can form the commo n metabolite 1,2,4

- triazole and two triazole conjugates ( triazolylalanine and triazolylacetic acid ). To support existing tolerances and to establish new tolerances for triazole

- derivat ive pesticides, including propiconazole , U.S. EPA conducted a human hea lth risk assessment for exposure to 1,2,4

- triazole, triazolylalanine, and triazolylacetic acid resulting from the use of all current andPage 28 of 70

pending uses of any triazole

- derived fungicide. The risk assessment is a highly conservative, screening

- level evaluati on in terms of hazards associated with common metabolites (e.g., use of a maximum combination of uncertainty factors) and potential dietary and non

- dietary exposures (i.e., high end estimates of both dietary and non

- dietary exposures). In addition, the Ag ency retained the additional 10X FQPA safety factor for the protection of infants and children. The assessment includes evaluations of risks for various subgroups, including those comprised of

infants and children. The Agency’s complete risk assessment i s found in the propiconazole reregistration docket at http://www.regulations.gov , Docket Identification (ID) Number EPA

HQ

- OPP

- 2005

- 0497.

9.0 OCCUPATIONAL EXPOSURE/RISK CHARACTERIZATION

Occupational handler and post

- application exposure scenarios are assessed for the risk

assessment of the uses . Based on the product labels and information provided by the registrant,

short

- and intermediate

- term exposure is assessed for occupational handlers and post

- application

activities. Chronic exposure is not expected for the proposed use patterns. Derma l and inhalation exposures to workers are aggregated for difenoconazole because the PODs for these routes are based on common toxicological effects.

9.1 Handler Exposure

The term “handler” applies to individuals who mix, load, and apply the pesticide product. There is a potential for exposure to difenoconazole during mixing, loading, and app lication activities through inhalation routes only

. Difenoconazole products are applied to using aerial, groundboom, chemigation

, and handheld sprayers

. The pro posed new post harvest use on potatoes is by automated spray application.

9.1 .1 Handler Exposure Scenarios

The following handler exposure scenarios evaluated for this assessment are based on information provided in the proposed labels.

9.2.1.1 Folia r Applications to Field Crops

• Open mixing/loading liquid formulation for groundboom, aerial, chemigation, and airblast application ;

• Applying with aerial, groundboom, and airblast sprayer equipment ; and

• Flagging for aerial application

.

9.2.1.2 Post

- Harvest Application to Potatoes

• Open mixing/loading liquid for automated spray application.Page 29 of 70

9.1.2 Handler Exposure Data and Assumptions

No chemical

- specific handler exposure data were submitted in support of this registration. It is the policy of HED to use the best available data to assess handler exposure. Sources of generic handler data, used as surrogate data in the absence of chemical

- specific data, include the Pesticide Handlers Exposure Database Version 1.1 (PHED 1.1), t he Agricultural Handler Exposure Task Force (AHETF) database, the Outdoor Residential Exposure Task Force (ORETF) database, or other registrant

- submitted occupational exposure studies. Some of these data are proprietary (e.g., AHETF data), and subject to the data protection provisions of FIFRA. The standard values recommended for use in predicting handler exposure that are used in this assessment, known as “unit exposures”, are outlined in the “Occupational Pesticide Handler Unit Exposure Surrogate Refere nce Table” (http://www.epa.gov/opp00001/science/handler

- exposure

table.pdf), which, along with additional information on HED policy on use of surrogate data, including descriptions of the various sources, can be found at http://www.epa.gov/pesticides/science/handler

- exposure

- data.html

.

• Average body weight of an adult handler is 8 0 kg.

• Dermal absorption factor is 6%

• Exposure duration short

- term (1

- 30 days), intermediate

- term (1

- 6 months)

• Maximum label application rates for aerial, groundboom and airblast to fruit, vegetable and berry crops :

- 0.0 7

– 0.1 3 lb ai/A

• Area treated for aerial, groundboom

, airblast and chemigation application to field crops :

- 350 acres per day for aerial application

- 80 acres per day for groundboom application

- 40 acres per day for airblast application

• Maximum label application rates post

- harvest use on potatoes

- 0.00025 gal ai / lb potato

• A mount of potatoes treated/processed

- 1,440,000 lbs per day (180,000 lbs per hour x 8 hrs per day)

9.1 .3 Handler Exposure and Risk Estimates

All worker exposures are assessed as short

- and intermediate

- term based on label prescribed uses and expected exposure durations. Exposure and risk estimates indicate non

cancer risks are not of concern for occupational handler activities for the proposed new uses (MOEs > 100). A summary of occupational handler exposure and risk calculations, assumptions,

and results are provided in Table s 1 2 and 1 3

.Page 30 of 70

Table 1 2

. Occupational Handler Short

- /Intermediate

- Term Dermal and Inhalation Exposure Estimated Risk

Exposure

Scenario Crop Unit Exposure 1
(ug/lb ai) App.

Rate 2

(lb ai/A) Area

Treated 3
(A/Day) ST & IT Dose

(mg/kg/day) ST & IT MOEs

LOC = 100 Combined

MOEs 8

LOC=100

Dermal

Base line Inh al

BL Dermal 4

Base line Inh al

. 5

Base line Dermal 6

Base line Inh al

. 7

Base line Inhal +

Dermal

Mixing/Loading

– Liquid

Groundboom

Citrus fruits

220 0.219 0.13 80 0.0017 0.000028 730 44,000 720

Airblast 40 0.00086 0.000014 1,500 88,000 1,400

Aerial &

Chem. 350 0.0075 0.00012 170 10,000 160

Groundboom Fruiting

Vegetables; Strawberry/

low growing berry 0.11 80 0.0015 0.000024 860 52,000 850

Airblast 40 0.0007 0.000012 1,700 100,000 1,700

Aerial &

Chem. 350 0.0064 0.00011 200 12,000 190

Groundboom

Pome

Fruits 0.07 80 0.0009 0.000015 1,400 82,000 1,300

Airblast 40 0.0005 0.00000 8 2,700 160,000 2,700

Aerial &

Chem. 350 0.0040 0.000067 310 19,000 300

Groundboom Strawberry/

low growing berry 0.11 80 0.0015 0.000024 860 52,000 850

Airblast 40 0.0007 0.000012 1,700 100,000 1,700

Aerial &

Chem. 350 0.0064 0.00011 200 12,000 190

Applying Liquid

Groundboom

Citrus fruits 78.6 0.34

0.13 80 0.00061 0.000044 2,000 28,000 1,900

Airblast 1770 4.71 40 0.0069 0.00031 180 4,100 170

Aerial N/A 0.068 350 N/A 0.000039 N/A 32,000 N/A

Groundboom Fruiting

Vegetables; Strawberry/

low growing berry 78.6 0.34

0.11 80 0.00052 0.000037 2,400 33,000 2,200

Airblast 1770 4.71 40 0.0058 0.00026 210 4,800 200

Aerial N/A 0.068 350 N/A 0.000033 N/A 38,000 N/A

Groundboom

Pome

Fruits 78.6 0.34

0.07 80 0.00033 0.000024 3,800 53,000 3,500

Airblast 1770 4.71 40 0.0037 0.00016 340 7,600 320

Aerial N/A 0.068 350 N/A 0.000021 N/A 60,000 N/A

Groundboom Strawberry/

low growing berry 78.6 0.34

0.11 80 0.00052 0.000037 2,400 33,000 2,200

Airblast 1770 4.71 40 0.0058 0.00026 210 4,800 200

Aerial N/A 0.068 350 N/A 0.000033 N/A 38,000 N/A

Flagging

Aerial Citrus fruits

11 0.35 0.13

350 0.0063 0.00020 200 6,300 190

Fruiting Vegetables; Strawberry/

low growing berry 0.11 0.0053 0.00017 240 7,400 230

Pome

Fruits 0.07 0.0034 0.00011 370 12,000 360Page 31 of 70

Table 1 2

. Occupational Handler Short

- /Intermediate

- Term Dermal and Inhalation Exposure Estimated Risk

Exposure

Scenario Crop Unit Exposure 1
(ug/lb ai) App.

Rate 2

(lb ai/A) Area

Treated 3
(A/Day) ST & IT Dose

(mg/kg/day) ST & IT MOEs

LOC = 100 Combined

MOEs 8

LOC=100

Dermal

Base line Inh al

BL Dermal 4

Base line Inh al

. 5

Base line Dermal 6

Base line Inh al

. 7

Base line Inhal +

Dermal

Strawberry/

low growing berry 0.11 0.0053 0.00017 240 7,400 230

1 Based on “Occupational Pesticide Handler Unit Exposure Surrogate Reference Table” (September 26, 2011); includes data from

PHED/ORETF/AHETF .

2 Based on proposed label.

3 Exposure Science Advisory Council Policy #9.1.

4 Dermal Dose = Dermal Unit Exposure (mg/lb ai) x Application Rate (lb ai/acre) x Area Treated (Acres/day) x DAF (6%)/BW (80 kg ).

5 Inhalation Dose = Inhalation Unit Exposure (mg/kg) x Application Rate (lb ai/acre) x Area Treated (Acres/day) x DAF (6%)/BW (80 kg).

6 Dermal MOE = Dermal NOAEL (1.25 mg/kg/day)/Dermal Dose (mg/kg/day). Level of concern = 100.

7 Inhalation MOE = Inhalation NOAEL (1.25 mg/kg/day)/ In halation Dose (mg/kg/day). Level of concern = 100.

8 Total MOE = NOAEL (mg/kg/day)/Dermal Dose + Inhalation Dose.

Table 1 3 . Occupational Handler Short

- and Intermediate

- Term Dermal and Inhalation Exposure and Risk Estimates

for Potato Post

- Harvest Use

Exposure

Scenario Solution

Conc. 2
(lb ai/gal soln) Amount

Treated/ Day 3
( gal/lb ) Amount

Processe d 4

(lbs /hr) Dermal

UE (mg/lb ai) Inhal.

UE 5
(mg/lb ai) Daily Dose 6

(mg ai/kg/day) MOEs

LOC=100

Dermal Inhal. Dermal Inhal.

Open Mixing/Loading Liquids 0.014 0.00025 180,000 0.220 0.000219 0.00084 0.000014 1,500 90,000

1. Liquid Formulation

– Thesis EPA Reg. No. 100

- 1386

2. Solution Concentration

- fl oz product/gal water x lb ai/gal product x 1 gal/128 fl oz (e.g. 0.3 fl oz product/0.5 gal water x 3 lb ai/gal product x 1 gal/128 fl oz) 3. Amount Treated Per day

- gallons/lb of tubers (e.g. 0.5 gal treats 2,000 lb tubers = 1 gal/4,000 lb tubers). Provided by the registrant, in an email correspondence.

4. Amount Processed

- lbs boxes per hour . Assumed that a packing facility could potentially pack 2,000 boxes per hour, each weighing 90 lbs (2,000 boxes/hr x 90 lbs /box = 180,000 lbs/hr) 5. Unit Exposure Values

- Baseline (e.g. no gloves or respirator)

6. Short

- a nd Intermediate Term Inhalatio n Daily Dose

- [Amount Processed (lb boxes/hr) x Amount Treated daily (gal/lb) x soln concentration (lb ai/gal soln) x Unit Exposure x 8 (hr/day) x absorption factor (0.06 dermal only ]/body weight

7. Short Term MOE

- NOAEL (1.25 mg/kg/day)/Daily Dose (mg ai/kg/day)

8. Intermediate Term MOE

- NOAEL (1.25 mg/kg/day)/Daily Dose (mg ai/kg/day)

9.2 Post

- Application Exposure

HED uses the term “post

- application” to describe those individuals who can be exposed to pesticides after entering areas previously tre ated with pesticides and performing certain tasks or activities (also often referred to as reentry exposure). Post

- application exposures are expected to occur primarily via the dermal route. Post

- application exposures are expected to occur primarily via the dermal route. Based on the Agency's current practices, a quantitative post application inhalation exposure assessment was not performed for difenoconazole. However, volatilization of pesticides may be a potential source of post application inhalation exposure to individuals nearby to pesticide applications. The Agency sought expert advice and input on issues related to volatilization of pesticides from its Federal Insecticide, Fungicide, and Rodenticide Act Scientific Advisory Panel (SAP) in December 2009. The Agency received thePage 32 of 70

SAP’s final report on March 2, 2010 and is in the process of evaluating the SAP report. The Agency may, as appropriate, develop policies and procedures to identify the need for and, subsequently, the way to incorporate post application inhalation exposure into the Agency's risk assessments. If new policies or procedures are put into place, the Agency may revisit the need for a quantitative post application inhalation exposure assessment.

9.2 .1 Post

- Application Exposure Scenarios

There are no compound specific data with which to estimate post

- application exposures to agricultural workers. Estimates of post

- application re

- entry exposure to agricultural workers are based upon the EXPOSAC Standard Operating Procedures (SOP s) (3.1, Reference 4). This

SOP lists a number of possible post

- application agricultural activities for the proposed crop uses

that m ight result in post

- application.

The following post

- application exposure scenarios were assessed for proposed post

emerg ence uses of difenoconazole.

- Citrus fruits, Crop group 10

- 10 ; hand harvesting, hand pruning, scouting, hand weeding,

orchard maintenance

- Fruiting Vegetable Crop group 8

- 10; irrigation (hand set) , hand h arvesting, tying/training

, transplanting

, scouting

, hand pruning ; scouting; thinning

, hand weeding

- Pome Fruit Crop group 11

- 10 ; hand harvesting, thinning, training , transplanting, hand weeding, propping, orchard maintenance.

- Strawberry and other low growing berry (subgroup 13

- 07 G , except cranberry) ; hand harvesting, leaf pulling, tying/training

, irrigation (hand set)

, scouting

, propagating , hand pruning

, trellis repair; transplanting , hand p runing (shears); hand weeding

, canopy management

- Post

- harvest potato; sorting, packing and culli ng treated potatoes

In accordance with the Worker Protection Standard (WPS), a 12

- hr restricted entry interval (REI) is required for chemicals classified under Toxicity Category III/IV.

9

. 2

. 2 Post Application Exposure Data and Assumptions for Field Crops

• Average body weight of an adult handler is 70 kg.

• Dermal absorption factor is 6%

• Exposure duration is 8 hrs per day

• Maximum label application rates:

- 0. 125 lb ai/A for citrus fruits

- 0.11 lb ai /A for fruiting vegetables

- 0.07 lb ai/A for pome fruit

- 0.114 lb ai/A for low growing berries

• Transfer Coefficients:

- 100

– 1400 cm 2 /hour for citrus fruit post

- application activities

- 70

– 1900 cm 2 /hour for fruiting vegetable post

- application activities

- 100

– 3600 cm 2 /hour for pome frui t post

- application activities

- 70

– 5500 cm 2 /hour for low growing berry post

- application activities

• Initial fraction of ai retained on foliage is 20%

• Exposure is assumed to occur on the day of application (day 0)Page 33 of 70

9.2.3 Post Application Exposure Assumptions for Post

- Harvest Potato

The proposed occupational uses for difenoconazole addressed in this document involve

post

- harvest applications, resulting in the potential for exposure during sorting, packing and culling treated potatoes. Therefore a dermal risk assessment was performed. The estimates of exposure is derived from residue chemistry data, surface area calculations, a reentry study for citrus (used as surrogate) found in the scientific literature, and a study monitoring the amount of

m aterial transferred during contact with a treated surface (Refer to ExpoSAC draft policy by D. Jaquith, 11/2005).

• A “standard” potato has a diameter of 2.25 to inches in diameter and weighs 213 grams;

• The residue level of pesticide for potatoes used in this assessment is 2.34 ppm ( μg /g) obtained from chemical specific data (highest average field trial (HAFT) for this commodity.

• All of the pesticide residue is on the surface of the commodity. The chemic al is not applied as a systemic product.

• Workers are assumed to perform the sorting/culling tasks for 8 hours per day.

• Dermal absorption is 6% for difenoconazole

.

• The transfer efficiency of the chemical is less than 2 percent.

• The transfer coefficient for the palmar surface of the hands only is 408 cm2 per hour.

9 .2 .4 Post

- Application Exposure and Risk Estimates

A target LOC or MOE of 100 is considered adequate for dermal exposure. Post

application e xposure and risk estim ates are not of concern (MOEs > 100 ). A summary of post

application exposure and risk calculations

, assumptions, and results is provided in Table s 1 4 and

1 5.Page 34 of 70

Table 1 4 . Estimated Difenoconazole Exposure & MOEs for Occupational Post

- Application Exposure

Exposure

Scenario Post

- application

Activities TC

(cm 2 /hr) App

Rate (lb ai/A) DFR

(mg/cm 2 ) Dermal

Dose (mg/kg/day) MOE

LOC =

100

Citrus fruits, Crop group 10

- 10 Harvesting, Hand 1400 0.125 0.00028 0.0024 530

Pruning, Hand; Scouting 580 0.125 0.00028 0.0010 1300
Transplanting 230 0.125 0.00028 0.0004 3200 Baiting/Trapping; Weeding, Hand; Orchard

maintenance 100 0.125 0.00028 0.0002 7400

Fruiting Vegetable, Crop group 8

- 10 Irrigation (hand set) 1900 0.11 0.00025 0.00281 440

Harvesting, Hand; Tying/Training 1100 0.11 0.00025 0.00163 770

Harvesting, Hand; Tying/Training 550 0.11 0.00025 0.00081 1500

Transplanting 230 0.11 0.00025 0.00034 3700
Scouting 210 0.11 0.00025 0.00031 4000 Pruning, Hand; Scouting; Thinning Fruit; Weeding,

Hand 90 0.11 0.00025 0.0001 9400

Weeding, Hand; Pruning,

Hand 70 0.11 0.00025 0.0001 12000

Pome Fruit, Crop Group 11

- 10 Thinning Fruit 3600 0.07 0.00016 0.0034 370

Harvesting, Hand 1400 0.07 0.00016 0.0013 950
Scouting; Pruning, Hand; Training 580 0.07 0.00016 0.00055 2300

Transplanting 230 0.07 0.00016 0.00022 5800
Weeding, Hand; Propping;

Orchard maintenance 100 0.07 0.00016 0.00009 13000

Strawberry and other low growing berry (subgroup

13

- 07G, except cranberry) Harvesting, Hand; Leaf

Pulling; Tying/Training 5500 0.114 0.00026 0.0084 150

Irrigation (hand set) 1900 0.114 0.00026 0.0029 430
Harvesting, Hand; Tying/Training; 1400 0.114 0.00026 0.0021 580

Harv esting, Hand; Harvesting; S couting; 1100 0.114 0.00026 0.0017 740

Propagating; Pruning, Hand; Scouting; Trellis Repair; Tying/Training; Weeding, Hand 640 0.114 0.00026 0.0010 1300

Transplanting 230 0.114 0.00026 0.00035 3500
Scouting 210 0.114 0.00026 0.00032 3900

Pruning, Hand (shears); Weeding, Hand; Canopy Management 70 0.114 0.00026 0.00011 12000

1. DFR = AR x F x (1

- D) t x 4.54E8 μg/lb x 2.47E

- 8 acre/cm 2
2. MOE = POD (NOAEL, 1.25 mg /kg/day) / Daily Dermal Dose. Daily Dermal Dose = [ DF R (μg/cm 2 ) x TC x 0.001 mg/μg x 8 hrs/day x 6 % dermal absorption] body weight 80 kg adult )

.Page 35 of 70

Table 1 5 . Summary of Estimated Post Harvest Post

- application MOEs for Potatoes

Chemical in Specific Commodity 1 (Potato) Commodity Specific

Surface area (cm2) Surface

Residue (μg/cm 2 ) Daily Dose 2

(mg /kg /day) Short & Int

Term MOE 3

LOC = 100 Chemical Residue μg /g (PPM) Commodity

Avg. Weight (g) Chemical

Residue (μg)/ Commodity

2.34 213 498 214 2.3 0.000114 11,000

1 Residue level calculations for potatoes based on highest average field trial

2 Daily Dose = [(408 cm2/hr) x (2.3μg/cm2) x (8 hrs/day) x (6% of Dermal Absorption) x (2% Transfer Efficiency) x (0.001 mg/μg)]/80 Kg

3 MOE mat = NOAEL / Daily Dose. (Short & Intermediate

- Term NOAEL = 1.25 mg/kg/day)

10.0 REFERENCES

Difenoconazole. Petition for Postharvest (PH) Use on Potatoes and Expansions of Existing Crop Group/Representative Commodity Uses to Fruiting Vegetables Group 8

- 10, Citrus Fruits Group

10

- 10, Pome Fruits Group 11

- 10, and Low growing Berry Subgroup 13

- 07G, Except Cranber ry. Summary of Analytical Chemistry and Residue Data, B. Cropp

- Kohlligian, D38 9912

, 5 / 30 /12

Difenoconazole. Acute and Chronic Aggregate Dietary Exposure and Risk Assessments for the Petition for Postharvest (PH) Use on Potatoes and Expansions of Existing Crop Group/Representative Commodity Uses to Fruiting Vegetables Group 8

- 10, Citrus Fruits Group

10

- 10, Pome Fruits Group 11

- 10, and Low growing Berry Subgroup 13

- 07G, Except Cranberry.
T. Morton, D 397664

, 5 / 30 /12

Difenoconazole. Occupa tional and R esidential Exposure Assessment to Evaluate the Risk from Proposed Uses on Post

- Harvest Potatoes, and the Expansion of Various Crop Groups Including: Citrus Fruit Group 10

- 10 ; Fruit ing Vegetable Subgroups 8

- 10; Low Growing Berry Subgroup

1 3

- 07 G, except cr anberry; Pome Fruit, Crop Group 11

- 10 and Fruiting Vegetable, Crop Group 8

- 10), Ivan Nieves, D398608, 5 / 30 /12

Difenoconazole (Parent Only) Drinking Water Assessment in Support of New Use Registration Action for Golf Course Turf. I. Maher, D371044, 6/1/ 10 , Updated EFED; Memo, F. Khan, 23

- February

- 2012; D398836

Difenoconazole. Request for Restatement of 1994 EPA Cancer Classification and Risk Assessment Approach Using Current Terminology. P.V. Shah, D 318039, 3/1/07

Difenoconazole

– with both available in vivo and in vitro dermal absorption studies, select an appropriate dermal absorption factor to be used for risk assessment, J. Chen, 12/18/08

Difenconazole : Summary of Hazard and Science Policy Council (HASPOC) Meeting of February 23, 2012: Recommendations on the need for a 28

- day inhalation study , D. Smegal, TXR#0054074, 3/5/12

.Page 36 of 70

APPENDI CES

A. TOXICOLOGY DATA SUMMARY

A.1 Guideline Data Requirements

Guideline

No. Study Type Technical MRID

No. Required Submitted

870.3100

870.3150

870.3200

870.3250

870.3465 Subchronic (Oral) Toxicity

- Rodent

................................ ....................

Subchronic (Oral) Toxicity

- Non

- Rodent

................................ ........... 21/28

- Day Dermal Toxicity

................................ ................................ .

90

- Day Dermal Toxicity

................................ ................................ ...... 90

- Day Inhalation Toxicity

................................ ................................ . Y

Y

N

N

N Y

Y

Y

N

N 42090022

42090021

4 2090013

42090013

46950310

870.3700a

870.3700b

870.3800 Prenatal Developmental Toxicity

- Rodent

................................ ..........

Prenatal Developmental Toxicity

- Non

- Rodent

................................ ..

Reproduction and Fertility Effects

................................ ....................... Y

Y

Y Y

Y

Y 42090016

42710008

42090017

42710008

42090018

870.4100a

870.4100b

870.4200a

870.4200b

870.4300 Chronic (Oral) Toxicity

- Rodent

................................ .........................

Chronic (Oral) Toxicity

- Non

- Rodent (Dog)

................................ ......

Carcinogenicity

- Rat

.................. ................................ ....................

Carcinogenicity

- Mouse

................................ ................................ ......

Combined Chronic Toxicity /Carcinogenicity Y

Y

Y

Y

Y Y

Y

Y

Y

Y 42090015

42710006

42090012

42710005

42090019

42710010

42090015

42710006

42090015

42710006

870.6100a

870.6100b

870.6200a

870.6200b

870.6300

870.7800 Neurotoxicity

- Acute Delayed Neurotox.

- Hen

................................ ...

Neurotoxicity

- Subchronic

- Hen

................................ ....................... Neurotoxicity

- Acute

- Rat

................................ ................................ .. Neurotoxicity

- Subchronic

- Rat

................................ .......................... Developmental Neurotoxicity.................. Immunotoxicity.............................

................................ .............. N

N

Y

Y

N

Y N

N

Y

Y

N

Y ---

--- 46950327

46950329

--

--Page 37 of 70

A .2 Toxic ity Profiles

Table A. 1

. Acute Toxicity Profile

– Difenoconazole

Guideline No. Study Type MRID No. Results Toxicity Category

870.1100 Acute oral 42090006 LD 50 = 1450 mg/kg III

870.1200 Acute dermal 42090007 LD 50 > 2010 mg/kg III

870.1300 Acute inhalation 42090008 LC 50 > 3.3 mg/L III

870.2400 Eye irritation 42090009 Mild irritation reversible in 7 days III

870.2500 Dermal irritation 40789807 Slight irritation IV

870.2600 Skin sensitization 42090011, 42710004 Negative N/A

Table A. 2

. Subchronic, Chronic and Other Toxicity Profile of Difenoconazole

Guideline

No. Study Type MRID No. (year)/

Classification /Doses Results

870.3100 90

- Day oral

toxicity (rat) 42090022 (1987)

Acceptable/guideline 0, 20, 200, 750, 1500 or 3000

ppm 0, 1, 10, 37.5, 75 and 150 mg/kg/d NOAEL = 20 ppm (1 mg/kg/day) LOAEL = 200 ppm (10 mg/kg/day) based on the 10% decrease in body weight in the 200 ppm females (as well as a negative trend in feed consumption) and Increases in absolute liver weights in both sexes

870.3100 90

- Day oral

toxicity (mouse) 42090021 (1987)

Minimum/guideline 0, 20, 200, 2500, 7500 or 15,000 ppm M: 0, 2.9, 30.8, 383.6, 1125 and 2250 mg/kg/d F: 0, 4.1, 41.5, 558.9, 1125 and 2250 mg/kg/d NOAEL = 20 ppm (2.9 mg/kg/day) LOAEL = 200 ppm (30.8 mg/kg/day) based on body weight changes & liver histopathology.

870.3150 26

- Week oral

toxicity 42090012 (1987)

Minimum/ guideline 0, 100, 1000, 3000 or 6000 ppm M: 0, 3.6, 31.3, 96.6 and 157.8 mg/kg/d F: 0, 3.4, 34.8, 110.6 and 203.7 mg/kg/d NOAEL = 3000 ppm (31.3 mg/kg/day in males/34.8 mg/kg/day in females) LOAEL = 6000 ppm (96.6 mg/kg/day in males/110.6 mg/kg/day in females) , based primarily on microscopic

examination of CGA 169374

- related lenticular cataracts.

870.3200 21/28

- Day dermal

toxicity (rat) 42090013 (1987)

Minimum/ guideline 0, 10, 100 and 1000 mg/kg/d NOAEL = 1 0 mg/kg/day LOAEL = 100 mg/kg/day based on statistically significant decrements in body weight, body weight gain, and food consumption.

870.3200 21/28

- Day dermal

toxicity (rat) 46950310 (2000)

Acceptable/ guideline 0, 10, 100 and 1000 mg/kg/d NOAEL (systemic) = 1000 mg/kg/day LOAEL (systemic) was not determined. NOAEL (dermal) = 100 mg/kg/day LOAEL (dermal) = 1000 mg/kg/day based on hyperkeratosis at the skin application site.

870.3700a Prenatal

developmental in (rat) 42090016, 42710007 (1987)

Mini mum/ guideline 0, 2, 20, 100 or 200 mg/kg/d

from GD 6

- 15 (nominal doses differed widely from theoretical, this required altering NOAEL/LOAEL values) Maternal NOAEL = 16 mg/kg/day

LOAEL = 85 mg/kg/day based on decreased body weight gain and food consumption. Developmental NOAEL = 85 mg/kg/day

LOAEL = 171 mg/kg/day based on alterations in fetal

ossification.Page 38 of 70

Table A. 2

. Subchronic, Chronic and Other Toxicity Profile of Difenoconazole

Guideline

No. Study Type MRID No. (year)/

Classification /Doses Results

870.3700b Prenatal

developmental in (rabbit) 42090017, 42710008 (1987)

Minimum/ guid eline 0, 1, 25 or 75 mg/kg/d from GD

7

- 19 Maternal NOAEL = 25 mg/kg/day LOAEL = 75 mg/kg/day based on decreased body weight gain and food consumption. Developmental NOAEL = 25 mg/kg/day LOAEL = 75 mg/kg/day based on nonsignificant increases in postimpla ntation loss and resorptions/doe and a significant decrease in fetal weight.

870.3800 Reproduction and

fertility effects (rat) 42090018 (1988)

Minimum/ guideline 0, 25, 250 or 2500 ppm 0, 1.25, 12.5 and 125 mg/kg/d Parental/Systemic NOAEL = 25 ppm (1.25 mg/kg/day) LOAEL = 250 ppm (12.5 mg/kg/day) based on reductions (statistically nonsignificant) in body weight gain which appear to be part of a dose

- related trend days 70

- 77 prior to mating, days 0

- 7 of gestation, an d days 7

- 14 of

lactation Offspring NOAEL = 25 ppm (1.25 mg/kg/day) LOAEL = 250 ppm (12.5 mg/kg/day) based on a significant reduction in the body weight of F1 male pups at day 21 in the 250 ppm group.

870.4100b Chronic toxicity

(dog) 42090012, 42710005 (1988)

Minimum/ guideline 0, 20, 100, 500 or 1500 ppm M: 0, 0.71, 3.4, 16.4 and 51.2 mg/kg/d F: 0, 0.63, 3.7, 19.4 and 44.3 mg/kg/d NOAEL = 100 ppm (3.4 mg/kg/day in males/3.7 mg/kg/day in females) LOAEL = 500 ppm (16.4 mg/kg/day in males/19.4 mg/kg/day in females) , based on significant inhibition of body weight gain in females.

870.4200 Carcinogenicity

(rat) 42090019, 42710010 (1989)

Minimum/ guideline 0, 10, 20, 500 or 2500 ppm M: o, 0.48, 0.96, 24.12 and 123.7 mg/kg/d F: 0, 0.64, 1.27, 32.79 and

169.6 mg/kg/d NOAEL = 20 ppm (0.96 mg/kg/day in males/1.27 mg/kg/day in females) LOAEL = 500 ppm (24.1 mg/kg/day in males/ 32.8 mg/kg/day in females) based on reductions in cumulative body weight gains in the 500 and 2500 ppm groups.

No evidence of carcinogen icity

870.4300 Carcinogenicity

(mouse) 42090015, 42710006 (1989)

Minimum/ guideline 0, 10, 30, 300, 2500 or 3000

ppm M: 0, 1.51, 4.65, 46.29, 423.1 and 818.9 mg/kg/d F: 0, 1.9, 5.63, 57.79 and 512.6 mg/kg/d NOAEL = 30 ppm (4.7 mg/kg/day in males/5.6 mg/kg/day in females) LOAEL = 300 ppm (46.3 mg/kg/day in males/57.8 mg/kg/day in females) based on reductions in the cumulative body weight gains and hepatocellular hypertrophy, liver necrosis, fatty changes in the liver and bile stasis in the 300, 2500 & 4500 ppm groups.

Evidence of carcinogenicity (liver adenoma/carcinoma in both sexes)

870.5100 In vitro bacterial

gene mutation (Salmonella typhimurium/ E. coli) / mammalian activation gene mutation assay 42090019, 42710010 (1989)

Minimum/ guideline

340

- 5447 μg/plate;

85

- 1362 μg/plate (repeat assay with TA1537 and TA98) There were sufficient and valid data to conclude that CGA 169374 technical was negative in the microbial gene mutation assay.Page 39 of 70

Table A. 2

. Subchronic, Chronic and Other Toxicity Profile of Difenoconazole

Guideline

No. Study Type MRID No. (year)/

Classification /Doses Results

870.5300 in vitro

mammalian cell gene mutation assay in mouse lymphoma cells 42090024 (1986)

Unacceptable/ guideline No conclusion can be reached from the three nonactivated and two S9 activated mouse lymphoma forward mutation assays conducted with difenoconazole technical. The study was seriously compromised.

870.5375 In vitro

Mammalian Cytogenetics (chromosomal aberrations) a ssay in Chinese

hamster CHO

cells 46950319 (2001)

Acceptable/ guideline 0, 21.99, 27.49, or 34.36 μg/mL (

- S9) 0, 34.36, 53.69 or 67.11 μg/mL (+S9) There was evidence of a weak induction of structural chromosomal aberrations over background in the presence of S9

- mix.

870.5375 In vitro

Mammalian Cytogenetics (chromosomal aberrations) a ssay in Chinese

hamster CHO

cells 46950321 (2001)

Acceptable/ guideline 0, 26.3, 39.5 or 59.3 μg/mL (

- S9) 0, 11.7 or 17.6 μg/mL (+S9) There was evidence of a weak induction of structural chromosomal aberrations over background.

870.5375 In vitro

Mammalian Cytogenetics (chromosomal aberrations) a ssay in human lymphocytes 46950323 (2001)

Acceptable/ guideline 0, 5, 30 or 75 μg/mL (

- S9) 0, 5, 30 or 62 μg/mL (+S9) There was no evidence of structural chromosomal aberrations induced over background.

870.5385 In vivo

mammalian

chromosomal

aberration test Assay in Mice 42090023 (1986)

Unacceptable/guideline 250, 500 or 1000 mg/kg There was no evidence of a cytotoxic effect on the target organ or significant increase in the frequency of nuclear anomalies (micronuclei). However, the study was compromised.

870.5395 In vivo

mammalian cytogenetics

- erythrocyte

micro nucleus assay in mice 41710011 (1992)

Acceptable/guideline Doses up to 1600 mg/kg Mice bone marrow

- No increase in micronucleated polychromatic erythrocytes occurred with CGA

- 1 69374 (91.2% a.i).

870.5550 Unscheduled

DNA Synthesis in

Mammalian Cells

in Culture 4210012 (1992)

Acceptable/ guideline Doses up to 50 μg/mL CGA

- i69374 tech. (92.2% a.i.) was considered to be negative in the unscheduled DNA synthesis assay in rat primary hepatocytes as measured by an autoradiographic method at concentrations up to 50.0 μg/mL.

870.5550 Unscheduled

DNA Synthesis in

Mammalian Cells

in Culture 42090027 (1985)

Unacceptable/ guideline

0.25

- 31.25 μg/mL No conclusion can be reached from the unscheduled DNA synthesis (UDS) primary rat hepatocyte assay

conducted with difenoconazole technical at concentrations ranging from 0.25 to 31.25 μg /mL. The sensitivity of the study was severely compromised.Page 40 of 70

Table A. 2

. Subchronic, Chronic and Other Toxicity Profile of Difenoconazole

Guideline

No. Study Type MRID No. (year)/

Classification /Doses Results

870.5550 Unscheduled

DNA Synthesis in

Mammalian Cells

in Culture 42090026 (1985)

Unacceptable/ guideline

0.08

- 10 μg/mL No conclusion can be reached from the unscheduled DNA synthesis (UDS) human fibroblast assay conducted with difenoconazole tech. at conc. ranging from 0.08 to 10 μg /mL.

870.6200a Acute

neurotoxicity screening battery 46950327 (2006)

Acceptable/ guideline 0, 25, 200 or 2000 mg/kg/d NOAEL (M) = 25 mg/kg/day LOAEL (M) = 200 mg/kg/day based on reduced fore

limb grip strength in males on day 1 and increased motor activity on Day 1

. NOAEL (F) = 200 mg/kg/day LOAEL (F) = 2000 mg/kg/day based on decreased body weight, the following clinical signs: upward curvature of the spine, tip

- toe gait, decreased activity, piloerection and sides pinched in and d ecreased motor activity.

870.6200b Subchronic

neurotoxicity screening battery 46950329 (2006)

Acceptable/ guideline 0, 40, 250, or 1500 ppm M; 0, 2.8, 17.3 or 107.0 mg/kg/d F: 0, 3.2, 19.5, or 120.2 mg/kg/d NOAEL (M) = 40 ppm (2.8 mg/kg/day) LOAEL (M) = 250 ppm (17.3 mg/kg/day) based on decreased hind limb strength. NOAEL (F) = 250 ppm (19.5 mg/kg/day) LOAEL (F) = 1500 (120.2 mg/kg/day) based on decreased body weight, body weight gain and food efficiency.

870.7485 Metabolism and

pharmacokinetics (rat) 42090028 (1990)

Acceptable/ guideline 14 daily doses of 0.5 or 300 mg/kg M ale and female Sprague

- Dawley rats. Animals were administered a single oral gavage dose of 0.5 or 300 mg/kg [ 14 C]CGA

- 169374, or 0.5 mg/kg unlabeled GGA

169374 by gavage for 1 4 days followed by a single gavage dose of 0.5 mg/kg [ 14 C)CGA

- 169374 on day 15. The test compound was labeled with C 14 at either the phenyl or triazole ring.

870.7485 Metabolism and

pharmacokinetics (rat) 42090028 (1990)

42090029 (1987) 42090030 (1987) 42090031 (1988) Acceptable/ guideline Single oral dose 0.5 or 300 mg/kg 14 daily doses of 0.5 or 300 mg/kg M ale and female Sprague

- Dawley rats. Animals were administered a single oral gavage dose of 0.5 or 300 mg/kg [ 14 C]CGA

- 169374, or 0.5 mg/kg unlabele d GGA

169374 by gavage for 14 days followed by a single gavage dose of 0.5 mg/kg [ 14 C)CGA

- 169374 on day 15. The test compound was labeled with C 14 at either the phenyl or triazole ring.

[ 14 C] CCA 169374 was rapidly and extensively distributed, metabolized, and excreted in rats for all dosing regimens. The metabolism of difenoconazole appears to be extensive because the metabolites accounted for most of the recovered radioactivity in the excrete. Three major metabolites were identified in the feces (i.e. metabolites A, B, and C). Two of the metabolites were separated into isomers (i.e., Al, A2, B1, and B2). Metabolite C was detected only in the high

dose groups, indicating that metabolism of

difenoconazole i s dose

- related and involves saturation of the metabolic pathway. Free triazole metabolite was

detected in the urine of triazole

- labeled groups and its byproduct was detected in the liver of phenyl labeled groups only. Other urinary metabolites were not

cha racterized.Page 41 of 70

Table A. 2

. Subchronic, Chronic and Other Toxicity Profile of Difenoconazole

Guideline

No. Study Type MRID No. (year)/

Classification /Doses Results

870.7485 Metabolism and

pharmacokinetics (rat) 42090028 (1990)

42090029 (1987) 42090030 (1987) 42090031 (1988) Acceptable/ guideline in conjunction with MRIDs 420710013, 42710014 listed

below Single oral dose 0.5 or 300 mg/kg 14 daily doses of 0.5 or 300 mg/kg The absorption, distribution, metabolism, and excretion of CGA 169374 were studied in groups of male and female Sprague

- Dawley rats. Animals were administered a single oral gavage dose of 0.5 or 300 mg/kg [ 14 C]CGA

169374, or 0.5 mg/k g unlabeled GGA

- 169374 by gavage for 14 days followed by a single gavage dose of 0.5 mg/kg [ 14 C)CGA

- 169374 on day 15. The test compound

was labeled with C 14 at either the phenyl or triazole ring.

[ 14 C] CCA 169374 was rapidly and extensively distributed, metabolized, and excreted in rats for all dosing regimens. the extent of absorption is undetermined pending determination of the extent of biliary excretion.

The 4

- day recoveries were 97.94

- 107.75% of the administered dose for all dosing groups. The elimin ation of radioactivity in the feces (78.06

- 94.61% of administered dose) and urine (8.48

- 21.86%) were almost comparable for all oral dose groups, with slightly higher radioactivity found in the feces of the high

- dose group

than the low

- dose groups. This was probably due to biliary excretion, poor absorption or saturation of the metabolic pathway. The radioactivity in the blood peaked

at about 24

- 48 hours for an dosing group. Half

- lives of elimination appear to be approximately 20 hours for the

low

- dose grou ps and 33

- 48 hours for the high

- dose group. The study results also indicate that difenoconazole

and/or its metabolites do not bioaccumulate to an appreciable extent following oral exposure since all the tissues contained negligible levels (< 1%) of radioac tivity 7 days postexposure.

The metabolism of difenoconazole appears to be

extensive because the metabolites accounted for most of the recovered radioactivity in the excrete. Three major metabolites were identified in the feces (i.e. metabolites A, B, and C). Two of the metabolites were separated into isomers (i.e., Al, A2, B1, and B2). Metabolite C was detected only in the high

- dose groups, indicating that

metabolism of difenoconazole is dose

- related and involves saturation of the metabolic pathway. Fre e triazole metabolite was detected in the urine of triazole

labeled groups and its byproduct was detected in the liver of phenyl labeled groups only. Other urinary metabolites

were not characterized.

These studies indicate that distribution, metabolism, a nd

elimination of CGA

- 169374 were not sex related. There was a slight dose difference in the metabolism and

elimination of CGA

- 169374. In phenyl and triazole labeling studies, fecal excretion of radioactivity was higher in the high dose animals compared to the low dose animals, and an additional metabolite was found in the feces of the high dose animals compared to the low dose animals. There was no major difference in the distribution and excretion of radioactivity with labeling at the phenyl

and triazole ring positions, however, there were some

different metabolites identified. The studies also showed that administration of 0.5 and 300 mg/kg CGA

- 169314 did not induce any treatment related clinical effects.Page 42 of 70

APPENDIX A .3 HAZARD IDENTIFICATION AND ENDPOINT SELECTION

A.3. 1 Acute Population Adjusted Doses (aPAD)

– All Populations

Selected Study: Acute Neur o toxicity Study in Rats

MRID 46950327 Dose and Endpoint for Establishing an aPAD : NOAEL is 25 mg/kg/day. LOAEL is 200 mg/kg/day based on reduced fore

- limb grip strength in males on day 1.

U ncertainty Factor (UF ): 100 This includes 10x for interspecies extrapolation and 10x for intraspecies variation. Comments about Study/Endpoin t : The selected e ndpoint is considered appropriate for acute dietary exposure because effects were seen after a single dose. The endpoint is protective of the general population and all subpopulations for effects seen in the acute neurotoxicity study in rats. It is also protective of developmental and maternal effects observed in the rabbit developmental toxicity study at the LOAEL of 75 mg/kg/day and NOAEL of 25 mg/kg/day.

A.3.2 Chronic Population Adjusted Dose (cPAD)

– All Populations

Selected Study: Chronic/Oncogenicity Study in Rats

MRID 42090019/20

D ose and Endpoint for Establishing an cPAD : The NOAEL is 0.96 mg/kg/day. The LOAEL is 24.12 mg/kg/day based on cumulative decreases in body weight gains at 24.12 mg/kg/day in

males

. Uncertainty Factor (UF ): 100 This includes 10X for interspecies extrapolation and 10x for intraspecies variation

.

A.3.3 Incidental Oral Exposure (Short

- Term)

Selected Study: Two Generation Reproduction Study in Rats

MRID 42090018 Dose and Endpoint for Establishing POD : The NOAE L is 1.25 mg/kg/day based on decreased pup weight in males at 12.5 mg/kg/day (LOAEL) on day 21 , and reductions in body weight gain

in F0 females. Uncertainty Factor (UF ): An MOE 100 is required for t he short

- and intermediate

- term scenarios for dermal exposure is based on the conventional uncertainty factor of 100. This includes 10x for interspecies extrapolation and 10x for intraspecies variation.

Comments about Study/Endpoint : There are no residential uses for difenoconazole that would General Population aPAD = (NOAEL) 25 mg/kg = 0. 25 mg/kg (UF) 100

General Population cPAD = (NOAEL ) 0.96 mg/kg/day = 0.0 1 mg/kg/day (UF) 100Page 43 of 70

result in incidental oral exposure to children. However, a short term oral exposure endpoint is required for aggregate risk assessment.

A. 3 .4 Dermal Absorption

A dermal absorption factor (DAF) is applied when dermal exposure endpoints are selected from oral toxicity studies. The dermal factor converts the oral dose to an equivalent

dermal dose for the risk assessment. A DAF of 6% was selected for use in risk assessment based

on available in vivo dermal absorption studies in rat and in vitro dermal absorption studies conducted with rat and human skin. The DAF was selected by a special working group of the Antimicrobials Division Toxicity Endpoint Selection Committee (12/18/08 memorandum from J.

Chen to M. Swindell

– Attachment A.3 ).

A. 3 .5 Dermal Exposure (Short and Intermediate

- Term)

Selected Study: Two Generation Reproduction Study in Rats ( MRID 42090018)

See Section A.4.3

Dose and Endpoint for Establishing POD : The NOAE L is 1.25 mg/kg/day based on decreased pup weight in males at 12.5 mg/kg/day (LOAEL) on day 21 and reductions in body weight gain in F0 females.. Dermal absorption is 6%.

Uncertainty Factor (UF ): An MOE 100 is required for the short

- and intermediate

- term

sce narios for dermal exposure is based on the conventional uncertainty factor of 100. This includes 10x for interspecies extrapolation and 10x for intraspecies variation.

Comments about Study/Endpoint : Although dermal toxicity studies are available, a POD from an oral study was selected because effects in young animals (decreased pup weight) the primary effect of concern for short, intermediate and long term exposure is not specifically evaluated in the available dermal toxicity studies that only assess adu lt animals. The selected endpoint is protective of offspring effects from dermal exposure. A DAF of 6% is applied to the POD for dermal exposure.

A

. 3

. 6 Inhalation Exposure (Short

- and Intermediate

- Term)

Selected Study: Two Generation Reproduction Study in Rats ( MRID 42090018)

See Section A .4.3Page 44 of 70

A.4 EXECUTIVE SUMMARIES FOR SUPPORTING TOXICITY STUDIES

A.4.1 Subchronic Toxicity

870.3100 90

- Day Oral Toxicity

– Rat MRID 42090022

CGA

- 169374 Technical was administered orally in feed admixtures to six groups of rats of both sexes at 0 ppm, 20 ppm, 200 ppm, 750 ppm, 1500 ppm, and 3000 ppm for 13 weeks. The results of this dietary subchronic evaluation of the toxicity of the test artic le were generally unremarkable. There was a significant trend for decreased body weights in both sexes, and the 200 ppm female rats showed an approximate 10% decrease in body weight relative to their controls concomitant with decreased food consumption. Th ere was one dose

— related effect of the chemical discovered during the histopathology examination, that identified modest diffuse hepatocellular enlargement, vis a vis. increased liver weights, in rats of both sexes at the two highest doses tested. Addition ally, although not statistically significant, compared to the other groups there was an increase in the frequency and quantity of ketones in the urine of group 6 males. The presence of elevated ketone levels may be due to gluconeogenesis driven by

decrease d protein intake from the diet as a result of decreased food intake. The somewhat compromised nutritional status of the rats could possibly and indirectly have promoted the hepatocellular enlargement as well. It is possible to conclude from this study, tha t based on approximately 10% decrease in body weight in the 200 ppm females (concomitant with a negative trend for food consumption) and increases in absolute liver weights in both sexes appearing at 750 ppm, the LOAEL is 200 ppm. The NOAEL was 20 ppm.

Cor e Classification: Minimum

870.3100 90

- Day Oral Toxicity

– Mouse MRID 42090021

CGA 169374 was offered in feed admixtures to five groups of mice composed of 15 animals/group/sex and 20 mice per sex for controls in dietary concentrations of 20 ppm, 200 ppm, 2500 ppm, 7500 ppm, or 15000 ppm for 13 weeks. Most of the mice fed 7500 ppm or 15,000 ppm test article, groups 5 and 6 respectively, died during the first week on study. There

were some CGA 169374

- related effects. The statistical analysis of total food consumption and body weight changes over the course of the study showed significa ntly reduced body weight gain for paired group 4 (2500 ppm) females and a significant negative trend. Compound

— related effects from histologic examination were confined to the liver. Hepatotoxicity in mice that DOS was evidenced by hepatocellular enlargeme nt and necrosis of individual hepatocytes. Those mice that survived to the end of the study showed hepatotoxicity that included hepatocellular enlargement in group 4 animals and group 3 males and hepatocytic vacuolization in group 4 animals. Furthermore, c oagulative necrosis was observed in the livers of 4/9 group 4 females. This finding, however, was not considered treatment related, because the foci were frequently small and random. The animals in groups 5 and 6, which represent the unscheduled deaths, ha d a high incidence of changes consistent with stress. The changes included lymphoid depletion or necrosis of the spleen, lymph nodes, and thymus, hypocellularity of the femoral marrow, mucosal erosion/ulceration of the glandular stomach, and in the female mice necrosis of individual cells in the adrenal cortex, specifically in the zona reticularis. Hyperkeratosis of thePage 45 of 70

nonglandular stomach was observed in males especially from group 6. The study director suggests the “stress” effects may be related to inap petence and a failure to eat as opposed to a direct effect of the test article. On the strength of the available data as they relate to the dose levels tested and to the parameters observed, the body weight changes and the liver histopathology form the bas is for setting the NOAEL at 20 ppm, and the LOAEL at 200 ppm. The mortality data indicate the MTD was exceeded and is likely S 7500 ppm.

870.3150 26 Week Oral Feeding study

– dog OPPTS MRID 42090012

CGA 169374 was offered in feed admixtures to five groups of beagle dogs composed of three animals/group/sex in dietary concentrations of 0 ppm, 100 ppm, 1000 ppm, 3000 ppm, or 6000 ppm for a minimum of 28 weeks. None of the dogs DOS. Compound

— related effects, developed essentially at the 3000 ppm and 6000 ppm dose levels. The singularly most striking compound effect was bilateral lenticular cataracts ophthalmoscopically

- observed in all dogs at 6000 ppm and in one female beagle at 3000 ppm. Additionally, iridic changes (irregular pupillary margins, miosis), seco ndary to lens induced uveitis, were also present in the affected animals. There were also reductions in mean body weight in females and males at 6000 ppm test compound throughout the study; weight loss was observed during the first three weeks on study.

Bo dy weight loss was precipitated by moderate to severe reductions in mean food consumption in females and males at 6000 ppm during the study with slight reductions observed in males at 3000 ppm and 1000 ppm and in one female at 3000 ppm. Furthermore, there were slight reductions in values for red blood cell count, hemoglobin, and hematocrit in females and males at 6000 ppm. There were also decrements in some serum clinical chemistry measurements including calcium and total protein in females at 6000 ppm and moderate increases in serum alkaline phosphatase in one or both sexes at 3000 ppm. There were modest alterations in several absolute and/or relative organ weight measurements to include the heart, prostate gland, salivary gland, uterus, kidney, liver, and brain at the highest dose tested (HOT). Nevertheless, liver weight measurements were also increased in Group 4 females. There were no other test article

— related changes in any other parameter examined. On the strength of the available data as they

relate t o the dose levels tested and the parameters observed, the LOAEL and the NOAEL for the test article in female and male beagle dogs were 3000 ppm and 1000 ppm, respectively, based primarily on microscopic examination of CGA 169374

- related lenticular cataract s. Core

Classification: Minimum

A.4.2 Prenatal Developmental Toxicity

870.3700a Prenatal Developmental Toxicity Study

– Rat MRID 42090016

CGA 169347 technical was administered by gavage on days 6

- 15 of gestation to presumed pregnant rats at 0, 2, 20, 100, or 20a mg/kg. Significant decreases in maternal body weight gain and feed consumption were observed during the dosing period for the feed consumption were observed during the dosing period for the 100 and 200 mg/kg groups. These animals also exhibited a significant increase in the incidence of excess salivation. There was a non significant decrease in the mean number of fetuses per dam, and non significant increases in the mean number of resorptions per dam and % postimplantation loss in the 200 mg/kg group. There was a slight (non significant) decrease in mean fetal body weight at the 200 mg/kg group. ThePage 46 of 70

following represents the significant alterations in the development of fetuses in the 200 mg/kg group. The incidence of bifid or unilateral ossification of the thoracic vertebrae was significantly increased on the fetal basis. There were also significant increases in the average number of

os sified hyoid and decreases in the average number of sternal centers of ossification (per fetus per litter). The average number of ribs was significantly increased (with accompanying increases in the number of thoracic vertebrae), and decreases in the numbe r of lumbar vertebrae in this group. These findings may be related to maternal toxicity. This study may be upgraded after satisfactory review of the response to the noted deficiencies. core classification: supplementary

. NOTE: Due to the relatively high p ercent deviation of the

actual doses tested from the theoretical concentration the effect levels have been modified accordingly. This modification may be subject to change as the purity is currently unknown.

Maternal NO A EL = 16 mg/kg; Maternal LOEL = 85 mg /kg ; Developmental Toxicity NO A EL = 85 mg/kg; Developmental Toxicity LO A EL = 171 mg/kg

870.3700b Prenatal Develo pmental Toxicity Study

– Rabbit MRID 42090017

CGA 169347 technical was administered by gavage on days 7

— 19 ofgestation to presumed

pregnant rabbits at 0, 1, 25, or 73 mg/kg. Maternal toxicity was observed in this study as the death of one doe and abortions observed in two other high dose does. In addition, significant reductions in body weight gain of high dose does, were present days 7

- 10, 10

— 14, 7

- 20, and 0

— 29. These reductions correspond with reduced feed consumption during these intervals (significant reductions in feed consumption in the HDT were only observed during the treatment period, not after treatment). Slight nonsignificant increas es in postimplantation loss and

resor p tions/doe were observed in the H D T. The significant decrease in fetal weight at the HDT may have been due to treatment. The significant differences in fetal weight observed at the low and mid dose were apparently not d ue to treatment. Core Classification: supplementary

Maternal NO A EL = 25 mg/kg; Maternal LOEL = 75 mg/kg Developmental Toxicity NO A EL 25 mg/kg; Developmental Toxicity LOEL = 75 mg/kg

A.4.3 Reproductive Toxicity

870.3800 Reproduction and Fertility Effects

– Rat MRID 42090018

In a two generation reproduction study, difenoconazole was administered in the diet to male and female rats at 0, 25, 250, or 2500 ppm [0, 1.25, 12.5, or 125 mg/kg/day, respectively].

Statistica l ly significant reductions in body weight gains of F0 and F1 males were observed at 2500 ppm during Days 70

- 77 and during the course of the study [terminal body weight minus Day 0 body weight ] . Significant r eductions in body weight gains of F0 and F1 females were seen during the pre

- mating, gestation, and lactation periods. A dose

- related, but non

- statistically significant decreases in body weight gain was seen in F0 females at 250 ppm during Days 70

- 77 prior to mating, Days 0

- 7 of gestation, and Days 7

- 14 of lactation: At 2500 ppm, signific ant reductions in pup body weight were detected on Days 0, 4 [pre

- and post culling], 7, 14, and 21 for males and females of both generations. There was a significant reduction in the body weight of F 1 male pups on Day 21 in the 250 ppm group. The percenta ge of male pups in the F1 generation surviving Days 0

- 4 was significantly reduced in the 2500 ppmPage 47 of 70

group: For parental toxicity, the LOAEL of 250 ppm [12.5 mg/ kg/day is based on the decreased maternal body weight gain; the NOAEL is 25 ppm [1.25 mg/kg/day. F or offspring toxicity, the LOAEL of 250 ppm [12.5 mg/kg/day] is base d on decreased pup weights at Day 21; the NOAEL is 25 ppm [1.25 mg/kg/day].

A.4.4 Chronic Toxicity

870.4100a (870.4300) Combined Chronic Toxicity/Carcinogenicity

– Rat MRIDs

42090019/

- 2 0

CGA 169374 was administered in the diet to male and female rats [80/sex/dose] for 104 weeks at 0; 10; 20; 500; and 2500 ppm. There were reductions in cumulative body weight gains in the 500 and the 2500 ppm gr oups. Mean liver weight was in cr eased at week 53 and t termination in the 2500 ppm group. Hepatocellular hypertrophy was observed in the 500 and the 2500 ppm animals at termination. Additional findings in the clinical chemistry data also indicated that liver was the primary target organ for toxic ity. No treatment related increased incidences of neoplastic findings were observed in this study. The NO A EL for the study was 20 ppm which was equal to 0.96 and 127 mg /kg / d for males and females respectively. The LO A EL was 500 ppm equal to

24.12 and 32.79 mg/kg/day for males and females respectively based on cumulative decreases in body weight gains. Discussion of Tumor Data No treatment related increased incidences of neoplastic findings were observed in this study. Adequacy of the Dose Levels Tested The dose levels tested were considered adequate by the Cancer Peer Review Committee. ( memorandum of July 27,1994 from B. Rinde of the Health Effects Division )

870.4100b Chronic Toxicity

- Dog MRID 42090012

CGA 169347 was administered in the diet to male and female dogs at 0, 20, 100, 500, or 1500 ppm. The NO A EL was 100 ppm and the L OA EL was 500 ppm based on the following. Females receiving 1500 ppm in the diet had a significant reduction in body weight gain on day 7. Females in the 500 and 1500 ppm groups, a lthough not statistically significant, had inhibited body weight gain throughout the study. These animals also had significant reductions in food consumption on days 7, 35, 70, and 357. The reduction in mean percent reticulocytes at the highest dose tested on day 359 may have been related to treatment, Significant increases (treatment related at day 85; dose

— related at days 175 and 359) were observed in alkaline phosphatase in males receiving 1500 ppm. This study may be upgraded upon satisfactory review of the registrants response to the deficiencies (submission of the purity and raw daily observation data).

Classification: core

— supplementary

A.4.5 Carcinogenicity

870.4200a Carcinogenicity/Chronic Study

– Mice MRIDs 42090015 and 42710006

CD

- I mice were fed diets containing difenoconazole at 0; 10; 30; 300; 2500or 4500 [males only]

for 78 weeks. The NO A EL was 30 ppm equal to 4.65 mg /k g/d in males and 5.63mg/kg/d inPage 48 of 70

females respectively. The LO A EL was 300 ppm equal to 46.29 mg/kg/d in males and 57.79mg/kg/ d in females based on reductions in the cumulative body weight gains at the higher

dose levels.

Discussion of Tumor Data: Difenoconazole was reviewed by the HED

- CPRC on May 18,1994 ( memorandum of July 27, 1994 from E. Rinde of the NED CPRC to C. Giles

- Par ker of RD) and classified as a Category C carcinogen without a q

- star. The margin

- of

- exposure ( MO E ) approach was selected because there was only very weak (limited) evidence of carcinogenic potential at dose levels not considered to be excessive with signi ficant changes observed only at excessive doses. There was no evidence for genotoxicity. There was a statistically significant increase in liver adenomas, carcinomas, and combined liver adenomas and carcinomas in both sexes at doses of 2500 and 4500 ppm. T hese doses were considered to be excessively high for cancer testing. Liver necrosis and liver adenomas were also noted in males at 300 ppm. There were no statistically significant increases in liver tumors at 10 or 30 ppm. Adequacy of the Dose Levels

Tes ted: The Health Effects Division Cancer Peer Review Committee considered the doses adequate and the study acceptable.

870.42 00b Carcinogenicity (feeding)

– Rat MRIDs 42090019/

- 20

CGA 169374 was administered in the diet to male and female rats [80/sex/dose] for 104 weeks at 0; 10; 20; 500; and 2500 ppm. There were reductions in cumulative body weight gains in the 500 and the 2500 ppm g r oups. Mean liver weight was in cr eased at week 53 and t termination in the 2500 ppm group . Hepatocellular hyper trophy was observed in the 500 and the 2500 ppm animals at termination. Additional findings in the clinical chemistry data also indicated that liver was the primary target organ for toxicity. No treatment related increased incidences of neoplastic findings were observed in this study. The NO A EL for the study was 20 ppm which was equal to 0.96 and 127 mg /kg / d for males and females respectively. The LO A EL was 500 ppm equal to

24.12 and 32.79 mg/kg/day for males and females respectively based on cumulative dec reases in body weight gains. Discussion of Tumor Data No treatment related increased incidences of neoplastic findings were observed in this study. Adequacy of the Dose Levels Tested The dose levels tested were considered adequate by the Cancer Peer Revie w Committee. ( memorandum of July 27,1994 from B. Rinde of the Health Effects Division )

A.4.6 Mutagenicity

Gene Mutation

Guideline # 870.5100 Bacterial assay 42090019, 42710010 Minimum/ guideline

Guideline #870.5300, In vitro mammalian cell gene mutation test

MRID 42090024
Unacceptable Guideline Not mutagenic

No conclusion can be reached from the three nonactivated and two S9 activated mouse lymphoma forward mutation assays conducted with difenoconazole technical. The study was seriously compromised.Page 49 of 70

Cytogenetics

Guideline # 870.5375, Clastogenicity in mammalian cells MRID 46950319, 46950321 Acceptable Guideline

MRID 46950323

Guideline #870.5395

Micronucleus test in bone marrow

MRID 41710011 Acceptable Guideline

Guideline #870.5550 Unscheduled DNA Synthesis in

Mammalian Cells in Culture 4210012 (1992) Acceptable/ guideline There was evidence of a weak induction of structural chromosomal aberrations over background in the presence of S9

- mix.

There was no evidence of structural chromosomal aberrations induced over background. Mice bone marrow

- No increase in micronucleated polychromatic erythrocyte s occurred with CGA

- 169374 (91.2% a.i).

CGA

- 169374 tech. (92.2% a.i.) was considered to be negative in the unscheduled DNA synthesis assay in rat primary hepatocytes as measured by an autoradiographic method at concentrations up to 50.0 μg/mL.

A.4.7 Neurotoxicity

870.6100 Delayed Neurotoxicity Study

– Hen

- NA

870.6200 Acute Neurotoxicity Screening Battery

– Rat MRID 46950327

In an acute neurotoxicity study (MRID 46950327), groups of fasted Alpk:APfSD Wistar

- derived rats (10/sex/dose), at least 42 days old, were g i ven a single oral dose of difenoconazole technical (CGA169374) (94.3% w/w, batch/lot # WM806228) in 1% w/v aqueous carboxymethylcellulose (CMC) at doses of 0, 25, 200, or 2000 mg/kg bw and ob served for 14 days. Dose levels selected for this study were based on the results of preliminary acute neurotoxicity study (MRID 46950325). Neurobehavioral assessm ent (fun ctional observational battery and motor activity testing) was performed on 10 animals /sex/group on days

- 7, 1, 8, and 15. Body weight and food consumption were measured weekly throughout the study. At study termination, 5 animals/sex/group were euthanized and per fu sed in situ for neuropathological examination; brain weight was recorded fro m these animals. Of the perfused animals, 5 animals/sex from the control and high dose groups were subjected to histopathological evaluation of brain and peripheral nervous system tissues.

There were no unscheduled deaths at any dose level. Weight change on the day of dosing by the control, low

- , mid

- , and high

- dose groups was

- 2.1,

- 1.0,

- 7.8, and

- 18.3 g, respectively, for males and 0.0, 2.1,

- 3.8, and

- 13.0 g, respectively, for females. Body weight for females had recovered to control levels by day 8. Food consumption for males given 2000 mg/kg was approximately 20% less than control during week 1 only (p< 0.01 ). Food consumption for these animals recovered to control levels during week 2. There were no differences from control for females at any dose level or for males at the lower dose levels. These effects on body weight and food consumption were not toxicologically significant.

At 2000 mg/kg, a number of adverse clinical signs were observed on day I (at the time of peak effect), including: upward c urvature of the spine (8 males, 9 females); tip

- toe gait (3, 8);Page 50 of 70

decreased activity (6, 7); piloerection (3, 5); sides pinched in (3, 7); and subdued (1, 0). Females

were affected more than males. All treatment

- related clinical signs observed on day 1 show ed complete recovery by day 5 (males) or day 7 (females). Significant decreases in fore

- limb grip strength were se en in mid

- ( 23%) and high

- dose (26%) males on day 1. Females dosed with 2000 mg/kg had lower motor activities on day 1 (37%), at the time of p eak effect, and on day 8 (31%). Males dosed with 200 or 2000 mg/kg had higher motor activities than the controls on day 1, 50% and 55%, respectively, at the time of peak

effect. There were no effects on brain weight at any dose level. Neuropathological exa mination of the central and peripheral nervous system showed no effects of treatment at doses of 2000 mg/kg in both sexes. The LOAEL for acute neurotoxicity of difenoconazole technical (CGA169374) in male rats is 200 mg /kg bw based on reduced fore

- limb gri p strength in males on day 1. The NOAEL is 25 mg/kg bw. The LOAEL for acute neurotoxicity of difenoconazole technical (CGA169374) in female rats is 2000 mg/kg . B ased on decreased body weight, the following clinical signs: upward curvature of the spine, ti p

- toe gait, decreased activity, piloerection and sides pinched in, and decreased motor activity. The NOAEL is 200 mg/kg bw.

870.6200 Subchronic Neurotoxicity Screening Battery

In a subchronic neurotoxicity study (MRID 46950329) difenoconazole technical (94.5% w/w, batch no. WM806228) was administered to groups of 12 male and 12 female Alpk:AP f SD (Wistar

- derived) rats at concentrations of 0, 40, 250, or 1500 ppm in the diet for 90 days. Respective dose levels corresponded to 0, 2.8, 17.3 or 107.0 mg/kg b w/day for males and 0, 3.2, 19.5, or 120.2 mg/kg bw/day for females. Neurobehavioral assessment (functional observational battery and motor activity testing) was performed in 12 animals/sex/group pretest and during weeks 2, 5, 9, and 14. Cholinesterase a ctivity was not determined. At study termination, 5 animals/sex/group were euthanized and perfused in situ for neuropathological examination. Of the perfused animals, 5/sex from the control group and 5/sex from the 1500 ppm group were subjected to histop athological evaluation of brain and peripheral nervous system tissues. Treatment with difenoconazole at concentrations up to 1500 ppm in the diet had no effect on mortality or clinical signs. Relative to respective control weight, final body weight of mal es and females in the 1500 ppm group was reduced by 9% and 7%. Body weight gain was reduced by

22% in males and 23% in females. Food consumption was reduced in this group (statistically significant only in females [7%]), and food efficiency was significa ntly reduced in males by 21% (p≤0.05) and in females by 21% (ns). Lower dose groups were unaffected. Absolute liver weight in males and females in the 1500 ppm group was increased over respective control weight by 38% and 45%

. Liver was not weighed in l ower dose groups. The increase in liver weight was considered a normal response to chemical treatment.

During weeks 2, 9 and 14, hind

- limb grip strength in males in the 1500 ppm group was reduced by 18 to 27% relative to the control values. At week 14, hind

- limb grip strength in males in the 250 ppm group was significantly (p≤0.05) reduced by 20% relative to the control values. FOB observations in females were unaffected by treatment. Motor activity was unaffected in both

sexes at all observation times . Brain weight was unaffected by treatment and there were no

treatment

- related neuropathological lesions.

The LOAEL in male rats is 250 ppm in the diet (17.3 mg/kg bw/day), based on decreased hindPage 51 of 70

limb strength. The NOAEL is 40 ppm (2.8 mg/kg bw/day). The LOAEL in female rats is 1500 ppm in the diet (120.2 mg/kg bw/day), based on decreased body weight, body weight gain and food efficiency. The NOAEL is 250 ppm (19.5 mg/kg bw/day). The study is classified as Acceptable/Guideline

A.4.8 Metabolism

870.7485 Metabolism

– Rat

Study 1 The absorption, distribution, metabolism, and excretion of difenoconazole were studied in groups of male and, female Sprague

- Dawley rats. Animals we re administered a single oral gavage dose of 0.5 or 300 mg/kg [ 14 C ] dif enoconazole or 0.5 mg/kg unlabeled difenoconazole by gavage for 14 days followed by a single gavage dose of 0.5 mg/kg [ 14 C] difenoconazole on day 15. The test compound was labeled with [ 14 C] at either the phenyl or triazole ring.

[ 14 C] CCA 169374 was rapidly and extensively distributed, metabolized, and excreted in rats for all dosing regimens. the extent of absorption is undetermined pending determination of the extent of biliary excretion. The 4

- day recoveries were 97.94

- 107.75% of the administered dose for all dosing groups. The elimination of radioactivity in the feces (78.06

- 94.61% of administered dose) and urine (8.48

- 21.86%) were almost comparable for all oral dose groups, with slightly higher radioactivity found in the feces of the high

- dose gr oup than the low

- dose groups. This was probably due to biliary excretion, poor absorption or saturation of the metabolic pathway. The radioactivity in the blood peaked at about 24

- 4 8 hours for an dosing group. Half

- lives of elimination appear to be approx imately 20 hours for the low

- dose groups and 33

- 48 hours for the high

- dose group. The study results also indicate that difenoconazole and/or its metabolites do not bioaccumulate to an appreciable extent following oral exposure since all the tissues contain ed negligible levels (< 1% ) of radioactivity 7 days postexposure.

The metabolism of difenoconazole appears to be extensive because the metabolites accounted for most of the recovered radioactivity in the excrete. Three major metabolites were identified in the feces (i.e. metabolites A , B , and C). Two of the metabolites were separated into isomers (i.e., Al, A2, B 1, and B 2). M etabolite C was detected only in the high

- dose groups, indicating that

metabolism of difenoconazole is dose

- related and involves sa turation of the metabolic pathway.

Free triazole metabolite was detected in the urine of triazole

- labeled groups and its byproduct was detected in the liver of phenyl labeled groups only. Other urinary metabolites were not

characterized.

These study resul ts indicate that distribution, metabolism, and elimination of difenoconazole

were not sex related. Th e re was a slight dose

- related difference in the metabolism and

elimination difenoconazole . In phenyl

- and triazole

- labeling studies, fecal excretion of

ra dioactivity was higher in the high

- dose animals compared to the low

- dose animals, and an additional metabolite was found in the feces of the high

- dose animals compared to the low

- dose animals. There were no major differences in the distribution and excreti on of radioactivity with labeling at the phenyl and triazole ring positions, however, there were some different metabolitesPage 52 of 70

ide n tified. The studies a lso showed that administration of 0.5 and 100 mg/kg difenoconazole did not induce any apparent treatment

- re lated clinical effects.

The study is cla ssi fied as acceptable guideline when considered together with data provided in

additional rat metabolism studies (MRIDs 42710014, 42710013) submitted as supplemental to this study . This study may be upgraded if the following additional information is provided and is judged to be acceptable:

Study 2 These studies (MRIDs 42710014, 42710013) were submitted because EPA requested additional information not provided in the Sponsor’s previously submitted metabolism studies ( M RID Nos.

420900

- 28/29/30/31). The present studies describe the absorption, distribution, and excretion, as well as pharmacokinetics, of [ 14 C] difenoconazole after a single oral gavage dose of 0.5 or 300 mg/kg in rats (Report 1) and isolated and identifi ed urinary metabolites in three females after a single oral gavage dose of 300 mg/kg (Report 2).

Following oral administration of 0.5 or 300 mg/kg 14 C

- CCA 169374 in rats, the test compound was adequately absorbed and mainly eliminated via the bile; no evidence of bioaccumulation in any tissue was noted. After 48 hours, total recovery (independent of dose and sex) was ≈ 96% of

the administered dose. Bil iary excretion constituted the main route of elimination with some

dose

- and sex

- dependency ( ≈ 75% at the low dose for both sexes; 56% for males and 39% for females at the high dose). Urinary and fecal eliminations exhibited a dose

- related pattern at 48

ho urs. In the urine, 9

- l4% was eliminated at the low dose versus 1% in the high

- dose rats. In the feces, 2

- 4% was eliminated at the low dose versus 17

- 22% at the high dose. In cannulated males after 48 hours, ≈ 80% was eliminated via the bile, while ≈ 4% an d ≈ 14% were eliminated via urine and feces, respectively. Therefore, this study indicates that most of the dose following oral administration is absorbed as indicated by the biliary excretion data. The dose

- related difference in elimination suggests that saturation is reached at the higher dose level resulting in an increase

of unabsorbed test material.

Maximum concentration in blood was reached within 2 hours at the low dose and 4 hours at the high dose. By 24 hours, <0.05 ppm equivalent was detected in the blood. Total recovery ranged from 95% to 97% after 48 hours, irrespective of dose and sex. During the first 12 hours, slight differences were evident between males and females with regard to Tmax, Cmax, and rate of

elimination. The concentration in fe males was approximately half of that in males and was

eliminated faster than in males. Mean half

- lives in males and females from Tmax to 12 hours, were 6.2 and 4.4 hours, respectively; from 24 to 168 hours, they were 2.8 and 3.7 days, respectively.

Follow ing administration of 300 mg/kg of ( 14 C

- phenyl) CGA 169374, 3 major urinary metabolites were identified: sulfate conjugates (and their isomers) of H O

- CGA 205375, isomers

of HO

- CGA 205375, and the hydroxyacetic metabolite of H0

- CGA 205373. The major urinary metabolites of CGA 169374 have been identified and no single unknown metabolite accounted

for >1.1% of the dose.

These studies alone do not meet the minimum requirements for Guidelines 85

- 1. However, thesePage 53 of 70

studies combined with previously submitted studies (MRID Nos. 420900

- 28/29/30/31) are considered to be acceptable,

A.4.9 Immunotoxicity

870.7800 Immunotoxicity

– Rat

A difenoconazole immunotoxicity has been submitted by the registrant and is under review.Page 54 of 70

A.4.1 Dermal ToxicityPage 55 of 70Page 56 of 70Page 57 of 70Page 58 of 70Page 59 of 70Page 60 of 70Page 61 of 70Page 62 of 70Page 63 of 70Page 64 of 70

B. METABOLISM

B.1 Chemical Names And Structures

Table B.1 Difenoconazole Nomenclature

. Chemical structure

Common name Difenoconazole

Company experimental name CGA

- 169374

IUPAC name 1

- ({2

- [2

- chloro

- 4

- (4

- chlorophenoxy)phenyl]

- 4

- methyl

- 1,3

- dioxolan

- 2

- yl}methyl)

- 1H

- 1,2,4

- triazole

CAS name 1

- [[2

- [2

- chloro

- 4

- (4

- chlorophenoxy)phenyl]

- 4

- methyl

- 1,3

- dioxolan

- 2

- yl]methyl]

- 1H

- 1,2,4

- triazole

CAS registry number 119446

- 68

- 3

Chemical structure of

CGA

- 205375 livestock

metabolite

Chemical structure of 1,2,4

- Triazole (1,2,4

- T)

Chemical structure of Triazolylalanine (TA)

Chemical structure of Triazolylacetic acid (TAA)Page 65 of 70

B. 2 Metabolism Summary Table

Table B

. 2 Maximum Residues of CGA

- 205374, CGA

- 205375, and CGA

- 189138 in Metabolism Studies Reflecting Foliar Appls.

Note: Excludes data reflecting 0

- day PHIs (parent was >85% of TRR ) and RACs having n o detectable residues of the subject

metabolites. Crop [MRID Citation] RAC Radiolabel

Position Number

of Appl s

. Times

Rate (lb ai/A) PHI

(days) Residues Expressed as ppm ( % of TRR )

Difenoconazole CGA

- 205374 CGA

- 205375 CGA

- 189138

Wheat [42090032] Stalks 14 C Phenyl 4 x 0.22 29 23 (50%)

-- -- -- 14 C Triazole 27 (50%)

-- 2.7 (5%)

-- Canola (Rape seed) [44701701] [44701702] Stalks 14 C Phenyl 2 x 0.11 53 0.745 (17.3%)

-- 0.608 (14.1%) 1 0.069 (1.6%) 2

14 C Triazole 0.828 (17.1%) 0.058 (1.2%) 2 0.828 (17.1%) 1

-- Pods 14 C Phenyl 0.570 (18.1%) 1 0.009 (0.3%) 2 0.340 (10.8%) 1 0.054 (1.7%) 2

14 C Triazole 0.814 (17.3%) 1 0.038 (0.8%) 2 0.612 (13.0%) 1

-- Seed 14 C Phenyl 0.022 (14.4%)

-- 0.012 (7.9%) 0.0004 (0.3%)

14 C Triazole 0.093 (4.1%)

-- 0.014 (0.6%)

-- Potato 3

[42090036] Foliage 14 C Phenyl 6 x 0.11 12 9.47 (76.4%) 0.14 (1.1%) 0.27 (2.2%) 0.07 (0.5%)

Tuber 14 C Phenyl 0.001 (8.7%) 0.0004 (3.1%) 0.0004 (3.0%)

-- Tomato [42090035] Foliage 14 C Phenyl 3 x 0.22 40 1.1 (31%) 0.12 (3.4%) 0.18 (5.2%)

14 C Triazole 2.1 (28%) 0.32 (4.3%)

-- 14 C Phenyl 2 x 0.22 14 1.3 (59.1%) 0.08 (3.8%) 0.09 (4.3%)

14 C Triazole 1.5 (52.1%) 0.10 (3.5%)

-- Tomato [42090038] [42090039] Foliage 14 C Phenyl 6 x 0.11 35 5.36 (64.7%) 0.32 (3.9%) 0.20 (2.4%) 4 0.08 (0.9%)

14 C Triazole 5.25 (68.0%) 0.13 (1.63%) 0. 76 ( 9.8 %) 5

-- Fruit 14 C Phenyl 0.11 (66.3%) 0.002 (1.4%) 0.005 (2.6%) 6

--

14 C Triazole 0.10 (50.9%) 0.001 (0.52%) 0.002 (0.74%) --

Grape [43673201] Fruit 14 C Phenyl 3 x 0.22 20 0.065 (51.2%) 0.005 (4.1%) 0.008 (6.6%) 0.005 (4.0%)

14 C Triazole 5 x 0.22 0.052 (45.1%) 0.002 (1.7%) 0.004 (3.5%)

-- Leaves 14 C Phenyl 3 x 0.22 4.260 (46.4%) 0.762 (8.3%) 0.395 (4.3%) 0.487 (5.3%)

14 C Triazole 5 x 0.22 1.821 (31.5%) 0.173 (3.0%) 0.225 (3.9%)

--Page 66 of 70

B. 3 Metabolic Pathways

Plant

Goat MetabolismPage 67 of 70

P roposed metabolic pathway in the rat (urine)Page 68 of 70

Proposed metabolic pathway in rat (feces). The ketone, CGA

- 205374, is presented as an intermediate from parent

to CGA

- 205375.Page 69 of 70

Proposed mechanism for formation of metabolites A & B by the NIH ShiftPage 70 of 70

C. PHYSICAL/CHEMICAL PROPERTIES

Table C. 1 Physicochemical Properties of Difenoconazole.

Parameter Value Reference

Melting point 78.6 oC DP#s 172067 and 178394, 10/26/92, R.

Lascola pH 6

- 8 at 20 oC (saturated solution)

Density 1.37 g/cm 3 at 20 oC

Water solubility 3.3 ppm at 20 oC

Solvent solubility g/100 mL at 25 oC :

n

- hexane: 0.5

1

- octanol: 35

toluene: 77

acetone: 88

ethanol: 89

Vapor pressure 2.5 x 10 - 10 mm Hg at 25 oC

Dissociation constant, pK

a pure grade (99.3% ± 0.3%) difenoconazole in water (with 4% methanol) at 20oC is 1.1 DP# 375159, 5/26/10, B. Cropp

Kohlligian

Octanol/water partition coefficient, Log(K OW ) 4.2 at 25 oC DP#s 172067 and 178394, 10/26/92, R.

Lascola

UV/visible absorption spectrum

max at about 200 and 238 nm (in methanol at 26 oC) PMRA Proposed Regulatory Decision Document on Difenoconazole, 4/14/99 (PRDD99

- 01)

D. REVIEW OF HUMAN RESEARCH

Klonne , D. (1999) Integrated Report for Evaluation of Potential Exposures to Homeowners and Professional Lawn Care Operators Mixing, Loading, and Applying Granular and Liquid Pesticides to Residential Lawns: Lab Project Number: OMA005: OMA001: OMA002. Unpubli shed study prepared by Riceerca, Inc., and Morse Laboratories. 2213 p. (MRID 44972201).

The PHED Task Force, 1995. The Pesticide Handlers Exposure Database, Version 1.1. Task Force members Health Canada, U.S. Environmental Protection Agency, and the Na tional Agricultural Chemicals Association, released February, 1995.