### 2

C arfentrazone

- ethyl ( i.e. , F8426) is the ethyl ester o f carfentrazone ( i.e. , F8426

- chloropropionic acid). Carfentrazone

- ethyl readily hydrolyzes to carfentrazone via aerobic microbial metabolism and alkaline hydrolysis ( degradation by anaerobic microbial metabolism is uncertain). Carfentrazone, however, is not readily biodegraded and is stable to hydrolysis. Aqueous photolysis may be a dominant route of degradation of carfentrazone in clear, shallow waters (photolysis on soil is uncertain). Additional major routes of dissipation of carfentrazone include le aching and runoff, due to its mobility in soil. Carfentrazone and its ethyl ester have low volatility and are not expected to bioconcentrate in aquatic or terrestrial organisms

.

Carfentrazone

- ethyl is a triazolinone (mode

- of

- action group E/14) that inhibits the enzyme protoporp hyrinogen oxidase (PPO), resulting in an accumulation of protoporphyrins that , in the presence of ultraviolet light, can be photoactivated into reactive oxygen radicals that have the potential to cause oxidative damage to cell membranes. This class of herbicides is referred to as light

- dependent peroxidizing herbicides (LDPHs), which have enhanced toxicity in the presence of solar ultraviolet light. Although LDPH toxicity to fish appears to increase as light intensity increase s, no definitive data have been submitted to allow for a determination regarding how much toxicity may increase in the presence of direct sunlight. The default toxicity factor is currently 29.

Carfentrazone

- ethyl is moderately toxic to fish and aquatic invertebrates on an acute basis. Some data are available to estimate chronic toxicity to fish (rainbow trout NOAEC = 118 μg a.i./L ); however, data have so far been inadequate to confidently estimate the light

- dependent peroxidizing enhancement to toxicity. Carfentrazone

- ethyl is very highly toxic to aquatic plants, which is expected given its herbicidal properties.

Carfentrazone

- ethyl is practically non

- toxic to terrestrial animals

. However, t oxicity data

are not available for passerine bird species that may in some cases be more sensitive than the mallard and bobwhite that are currently tested

. The chief terrestrial risk is to non

- target plants. Incident reports confirm that carfentrazone

- ethyl use may cause damage to non

- target plants. T oxicity data using a typical end

- use product is needed to adequately characterize risk to plants.

### 3



# Problem Formulation for the Environmental Fate, Ecological Risk , Endangered Species, and Drinking Water Exposure Assessment s in Support of the Registration Review of Carfentrazone

- ethyl

CAS Registry Number: 1 28639

- 02

- 1 PC Code: 128712

Prepared by: Greg Orrick, Environmental Scientist Donna R. Judkins, Ph.D., Biologist U. S. Environmental Protection Agency Office of Pesticide Programs Environmental Fate and Effects Division Environmental Risk Branch I I 1200 Pennsylvania Ave., NW Mail Code 7507P Washington, DC 20460 Reviewed by: R. David Jones, Ph.D., Senior Agronomist Jean Holmes, DVM,MPH, Risk Assessment Process Leader Brian Anderson, Branch Chief



### March 8 , 2011

### 4

Table of Contents

1. Purpose

................................ ................................ ................................ ................................ 5 2. Problem Formulation

................................ ................................ ................................ .......... 5 2.1. Natur e of Regulatory Action

................................ ................................ ................................ 5 2.2. Previous Risk Assessments

................................ ................................ ................................ .. 5 2.2.1. Ecological Risk Assessments

................................ ................................ ........................ 5 2.2.2. Drinking Water Exposure Assessments

................................ ................................ ........ 7 2.2.3. Clean Water Act Programs

................................ ................................ ........................... 7 3. Stressor Source and Distribution

................................ ................................ ........................ 8 3.1. Overview of Pesticide Usage

................................ ................................ ............................. 10 3.2. Environmental Fate and Transport

................................ ................................ .................... 11 4. Receptors

................................ ................................ ................................ ........................... 15 4.1. Aquatic and Terrestrial Effects

................................ ................................ .......................... 16 4.2. Incident Database Review

................................ ................................ ................................ . 25 4. 3. Ecosystems Potentially at Risk

................................ ................................ .......................... 26 5. Assessment Endpoints

................................ ................................ ................................ ...... 26 6. Conceptual Model

................................ ................................ ................................ .............. 28 6.1. Risk Hypothesis

................................ ................................ ................................ ................. 28 6.2. Concept ual Diagram

................................ ................................ ................................ .......... 29 7. Analysis Plan

................................ ................................ ................................ ..................... 31 7.1. Stressors of Concern

................................ ................................ ................................ .......... 32 7.2. Measures of Exposure

................................ ................................ ................................ ........ 32 7.3. Measures of Effect

................................ ................................ ................................ ............. 34 7.4. Int egration of Exposure and Effects

................................ ................................ .................. 35 7.5. Endangered Species Assessments

................................ ................................ ...................... 35 7.6. Drinking Water Assessment

................................ ................................ .............................. 36 7.7. Endocrine Disruptor Screening Program

................................ ................................ ........... 36 7.8. Preliminary Identification of Data Gaps

................................ ................................ ............ 37 7.8.1. Environmental Fate

................................ ................................ ................................ ..... 37 7.8.2. Effects

................................ ................................ ................................ ......................... 39 8. References

................................ ................................ ................................ ......................... 44 APPENDIX A: Car fentrazone

- ethyl Eco Effects Bibliography

................................ .................. 48 APPENDIX B: Environmental Degradates of Carfentrazone

- ethyl.

................................ ........... 54 APPENDIX C: Data Call

- In Tables.

................................ ................................ ........................... 58

### 5

1. Purpose

The purpose o f this problem formulation is to provide a better understanding of the environmental fate and ecological effects of carfentrazone

- ethyl, considering its currently registered uses

. 

### Carfentrazone

- ethyl is a triazolinone herbicide used to control broadleaf w eeds and grasses in a wide range of agricultural crops, turfgrass, non

- agricultural areas, and aquatic areas including water bodies and wetlands. It provides a plan for analyzing relevant data for carfentrazone

- ethyl and conducting updated ecological risk and drinking water assessments for registered uses. Additionally, this problem formulation identifies remaining data gaps, uncertainties and potential assumptions used to address those uncertainties in characterizing the ecological risk associated with t he registered uses of carfentrazone

- ethyl.

2. Problem Formulation

2.1. Nature of Regulatory Action

This report summarizes the Environmental Fate and Effects Division‟s (EFED) Problem Formulation for the Registration Review of carfentrazone

- ethyl.

The Food Quality Protection Act of 1996 mandated the Environmental Protection Agency (EPA or the Agency) to implement a new program, i.e ., registration review ( http://www.epa.gov/oppsrrd1/registrat ion_review/ ). All pesticides distributed or sold in the United States generally must be registered by the EPA. The decision to register a pesticide is based on the consideration of scientific data and other factors showing that it will not cause

unreason able risks to human health, workers, or the environment when used as directed on product labeling. The registration review program is intended to ensure that, as the ability to assess risk evolves and as policies and practices change, all registered pesti cides continue to meet the statutory standard of no unreasonable adverse effects to human health and the environment. Changes in science, public policy, and pesticide use practices will occur over time. Through the new registration review program, the Age ncy periodically reevaluates pesticides to make sure that as change occurs, products in the marketplace can be used safely.

As part of the implementation of the new Registration Review program pursuant to Section 3(g) of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its evaluation to determine whether carfentrazone

- ethyl continues to meet the FIFRA standard for registration. This problem formulation for the environmental fate and ecological risk assessment chapter in support of the registration review is intended for the initial docket opening the public phase of the review process.

2.2. Previous Risk Assessments

2.2.1. Ecological Risk Assessments

Previous Assessments The most recent risk assessments available in the docket which serve as the basis for this problem formulation include the following:

### 6

Experimental

- use permit s for F8426 Herbicide use on wheat, corn, soybeans and sorghum, 199 5 and 199 7 ( D P 205680 and 221704) New use assessment for sweet corn, sorghum and rice, 1999 (D P 261660) 1


### New use assessment for caneberries (raspberries and blackberries) , turf and cotton, 2001 (D P 272622, 272623 , and 272733) 2 

### Section 18 for use on sweet corn to control broadleaf weeks in Wisconsin, 2001 (D P 265843). Section 18 fo r use on hops for mildew control in Washington, Oregon and Idaho, 2001 (D P 273524, 273680, and 273683) Section 18 for use on fruiting vegetables in Florida for control of nightshade, purslane and morninglory, 2002 (D P 282105) New use as an aquatic herbicid e, 2004 (D P 294782) 3


### New use assessment (including drinking water and eco logical assessment) for grapes, tobacco, citrus, pome and stone fruits, tree nuts including pistachio, and tuberous and corm vegetables, April 29, 2004 (D P 296368) 4 

### Memo conveying Enumeration of Endangered Plant Species for Proposed Use of Carfentrazone

- ethyl on Various Crops, August 2, 2004 (D P 299145) August 5, 2004 memo (D P 293217) conveying the DER for MRID 46037001, accepting the rainbow trout early life

- stage study under UVL c onditions. January 25, 2006 data call

- in (DCI 128712

- 26285 ) asking for special LDPH study. November 23, 2009 memo (D P 333793) reclassifies MRID 460370 0 1 as “Supplemental, for qualitative use only” (does not satisfy DCI 128712

- 26285). Label amendment assess ment for rice, 2011 (DP 384371)

S everal ecological risk assessments for carfentrazone

- ethyl concluded risk and uncertainties in the following area: risk to aquatic and terrestrial plants from many uses, especially aerial application to corn and sorghum; acute and chronic risk to fish, aquatic plants and shoreline terrestrial plants from use as an aquatic herbicide; and chronic risk to fish from use on caneberries; uncertainty in the degree to which toxicity may be increased in the presence of sunlight;
pr imary data gaps identified included a modified early life stage study in fish to evaluate enhanced toxicity in the presence of sunlight and terrestrial plant toxicity studies using a TEP.

1 Carfentrazone

- ethyl Herbicide Environmental Fate and Ecological Effects Assessment and Risk Characterization for a Section 3 for Use on Sweet Corn, Sorghum, and Rice (J. Carleton, N. Mastrota, 12/2/99; DP 261660).
2 New uses of Carfentrazone

- ethyl on caneberry, cotton, and turf. 2001 (J. Carleton, R. Felthousen and W. Eckel DP 272622, 272623 and 272733).
3 New use of carfentrazone

- ethyl as an aquatic herbicide, July 1, 2004 (W. Erickson and W. Eckel, DP 294782).
4 Drinking Water and Ecological Assessment for Proposed New Uses of Carfentrazone

- ethyl on Grapes, Tobacco, Citrus, Pome and Stone Fruits, Tree Nuts including Pistachio, and Tuberous and Corm Vegetables Subgroup., April 29, 2004 (W. Erickson, DP 2 96368).

### 7 2.2.2. Drinking Water Exposure Assessments

A new chemical d rinkin g water exposure assessment wa s conducted for carfentrazone

- ethyl in November 1999 (DP barcode 240937). The use pattern of highest exposure estimates was rice, with acute and chronic total residue e stimat ed drinking water concentrations (EDWC) in surface
water of 205 μg/L and 7 μg/L, respectively

. These values were based on field study data and a 2x dilution factor rather than model estimates. Assumptions used in this drinking water assessment were later revised (DP barcode 384371, USE PA, 2011). Total residues included the parent compound, F8426

- chloropropionic acid, F8426

- cinnamic acid, F8426

- propionic acid, F8426

- be nzoic acid, and 3

- hydroxymethyl

- F8426

- benzoic acid. Surface water and ground water total residue EDWCs for use on sweet corn and sorghum were up to 1.7 μg/L and 6.6 μg/L, respectively. A Section 18 assessment conducted in May 2000 (DP barcode 265843) relied upon the 1999 DWA exposure estimates.

In February 2001, a drinking water exposure assessment was conducted for prop osed new uses (DP barcode 271184+). Residues of concern were represented by modeling only the chloropropionic acid of carfentrazone

- ethyl ( i.e. , carfentrazone acid). Surface water exposure estimates for acute and chronic exposure were 21 μg/L and 20 μg/L (56

- day mean), respectively. The ground water EDWC was 13 μg/L.

A Section 18 assessment of use on fruiting vegetables in Florida was conducted t he following year, in April 2002 (DP barcode 282105). In this assessment, ca neberries remained the use of

max imum exposure estimates (excluding use on rice). Once again, residues of concern were represented by modeling carfentrazone acid. Surface water exposure estimates for acute and chronic exposure were 34 μg/L and 19 μg/L (annual mean), respectively. The gr ound water EDWC was 13 μg/L. Assessments of multiple agricultural crops and aquatic uses conducted in October 2003 (DP barcode 293780+) and May 2004 (DP barcode 296368) relied upon the maximum exposure estimates of the 2002 Section 18 assessment for use i n human health dietary risk assessment.

The most recent drinking water exposure assessment was conducted in 2011 for proposed label amendments to the current use on rice (DP barcode 384371). C arfentrazone

- ethyl, its acid (carfentrazone), and its cinnamic acid were the residues of concer n in drinking water. Surface water exposure was estimated with the Tier I Rice Model that was provisionally modified to estimate degradation using laboratory data. The proposed label amendments and the currently labeled u se on rice resulted in similar surface water exposure estimates of 125

- 126 μg/L (peak exposure) and 48 μg/L (chronic exposure).

2.2 .3 . Clean Water Act Programs

Aquatic Life Criteria and Aquatic Life Benchmarks

The Clean Water Act requires the Agency to publish water quality criteria that accurately reflect the latest scientific knowledge on the kind and extent of all identifiable effects on health and welfare which might be expected from the presence of pollutants in any body of water, including ground water. While these recommended criteria do not, in themselves, impose any

### 8

requirements, states and authorized tribes can use them to develop water quality standards. An Aquatic Life Ambient Water Quality Criteria document has not been published for carfent razone

- ethyl (refer to url: http://www.epa.gov/waterscience/criteria/ ).

Based on toxicity values revised by the EPA, the OPP publishes aquatic life benchmarks for freshwater species, based on the most sensitive species from the most recent risk assessments. For carfentrazone

- ethyl, no aquatic life benchmarks have been published (see url: http://www.ep a.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm#benchmarks ).

Impaired Water Bodies

Carfentrazone

- ethyl is not identified as a cause of impairment for any water bodies listed as impaired under section 303(d) of the Clean Water Act, based on inform ation provided at http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88 5 . No Total Maximum Daily Load (TMDL) c riteria have been developed for carfentrazone

ethyl, based on information provided at http://iaspub.epa.gov/tm dl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id =885&p_pollutant_group_name=PESTICIDES . More information on impaired water bodies and TMDLs can be found at http://www.epa.gov/owow/tmdl/ . Th e Agency invites submission of water quality data for this pesticide. To the extent possible, data should conform to the quality standards in Appendix A of the OPP Standard Operating Procedure: Inclusion of Impaired Water Body and Other Water Quality Data in OPP’s Registration Review Risk Assessment and Management Process (see: http://www.epa.gov/oppsrrd1/registration_review/water_quality_sop.htm ) , in order to ensure they can be used quantitatively or qualitatively in pesticide risk assessments.

3. Stress or Source and Distribution

Carfentrazone

- ethyl is registered for use as an herbicide on a myriad of vegetable, field, orchard, and non

- agricultural sites. Agricultural sites for which carfentrazone

- ethyl is registered for use include those of the crop groups for root and tuber vegetables, bulb vegetab les, leafy vegetables including brassica vegetables, legume vegetables, fruiting vegetables, cucurbit vegetables, citrus fruits, pome fruits, stone fruits, berries and small fruits, tree nuts, cereal grains, hay, and spices. Additional agricultural sites include cotton, dates, fallow land, figs, hops, okra, olives, peanuts, persimmons, pomegranates, sugarcane, sunflowers, tobacco, and other tropical and subtropical crops including avocados, bananas, cocoa, tea, Indian mulberries, vanilla, coconuts, palms, coffee, guayule, atemoyas, cherimoyas, biribas, canistels, feijoa, jaboticaba, longans, mangos, papayas, pulasans, rambutans, sapodillas, sapotas, soursops, star apples, and teosinte. Non

agricultural sites include ornamentals (including trees, grasses, a nd other plants), turf, grass grown for seed, uncultivated land, commercial areas including airports, farm premises, residential areas, recreational areas, pastures and rangeland, forests and tree plantations (including Christmas tree plantations), rights

- of

- way, paved areas, drainage systems, mine sites, and aquatic areas (including water bodies and wetlands).

Table 3.1 lists the use patterns of maximum exposure for the current uses of carfentrazone

- ethyl. Assessment of labeled uses on avocados and cof fee will be used as a surrogate for assessment of

### 9

the remaining labeled tropical and subtropical crops ( i.e. , bananas, cocoa, tea, Indian mulberries, vanilla, coconuts, palms, guayule, atemoyas, cherimoyas, biribas, canistels, feijoa, jaboticaba, longans, mangos, papayas, pulasans, rambutans, sapodillas, sapotas, soursops, star apples, and teosinte). The extent of production of many of these crops in the United States and its territories is unclear.

TABLE 3.1. Labeled Carfentrazone

- ethyl Use Patterns of M aximum Exposure.

Use Max.

Single App. Rate (lbs a.i./A) Max. No.

of App.
per Season Min.

Reapp. Interval (d) Max. Seasonal App. Rate (lbs a.i./A) Max. No.

of Seasons per Year A Max.

Annual App. Rate (lbs a.i./A) App.

Type

Pastures, millet NS B NS NS NS TBD D TBD Aerial
Cotton NS NS 10 NS 1 NS Ground Rice, wild rice 0.23 NS NS 0.35 1 0.35 Ground
Jerusalem artichokes 0.13 NS NS 0.038 TBD TBD Ground
Cane berries 0.12 NS 14 0.46 1 0.46 Ground

Potatoes 0.099 NS NS 0.21 1 0.21 Aerial
Ornamental turf 0.098 NS 14 NS 4 NS Ground Fallow land, airports, commercial premises, forest/tree farms, golf course turf, residential premises, rights

- of

- way, uncultivated non

- ag. areas, paved areas, water bodies 0.094 NS NS NS NA NS Aerial

Hay, grass for seed, rangeland, sod

farms 0.092 1 NA 0.092 2 0.18 Aerial

Recreational areas 0.055 NS NS NS 4 NS Aerial Cabbage, Christmas trees, commercial lawns, fencerows, industrial areas, ornamental trees and plants, residential lawns, sugarcane, tobacco 0.042 NS NS NS 4 NS Aerial F

Farm premises, mine sites 0.040 NS NS NS NA NS Aerial Legume veg., sorghum 0.036 NS NS NS 1 NS Aerial Grapes, hops, some vegetables, stone fruits, tree nuts 0.036 NS 14 0.14 1 0.14 Aerial G

Brassica veg., bush berries, cucurbit veg., spice crops, fruiting veg., leafy veg., root and tuber veg. 0.036 NS NS 0.11 3 0.33 Aerial

Cereal grains (barley, corn, oats, rye, rice, wild rice, buckwheat, teosinte, triticale, and wheat) 0.036 1 NA 0.036 3 0.11 Aerial

Tree nuts, stone fruits, citrus fruits, pome fruits, subtropical and tropical fruits such as avocados, bananas and coffee 0.031 NS 14 E 0.20 1 0.20 Ground

Cranberries, mangos 0.031 NS NS 0.12 1 0.12 Ground
Recreational lawns 0.031 NS 14 0.093 3 0.28 Ground Peanuts, sunflowers 0.028 NS NS NS 1 NS Aerial

### 10 Use Max.

Single App. Rate (lbs a.i./A) Max. No.

of App.
per Season Min.

Reapp. Interval (d) Max. Seasonal App. Rate (lbs a.i./A) Max. No.

of Seasons per Year A Max.

Annual App. Rate (lbs a.i./A) App.

Type

Bermuda grass 0.028 NS NS NS NA NS Ground Artichokes, okra, bulb veg. 0.017 NS NS 0.52 3 1.6 Ground

Water, swamp, wetland, drainage

system 0.54 lbs

a.i./acre

- ft NS 14 NS NA C NS Injection

0.20 lbs a.i./acre

- ft NS 14 NS NA NS Boat,

etc.

A Based on data regarding California agriculture provided in a memo from BEAD to EFED (USEPA, 2007).
B NS means “not stated”.
C NA means “not applicable”.
D TBD means “to be determined”.
E Reapplication interval is 14 days for a seasonal maximum application rate of 0.20 lbs a.i./A but is also not stated for some uses for a seasonal maximum application rate of 0.12 lbs a.i./A.
F Aerial application for cabbage, ground application for other uses.
G Aerial application for grapes, ground application for other uses.



### Conservative assumptions will be made for maximum application rates (single, seasonal, or both) and minimum reapplica tion intervals (3 days is the default assumption) if they are not stated on the current labels.

3.1. Overview of Pesticide Usage

Based on a Screening Level Usage Analysis conducted by the Agency (USEPA 2010) , using data from 2001 to 2007, roughly 46,000 pounds of carfentrazone

- ethyl are applied annually to agricultural crops. Carfentrazone

- ethyl usage is highest on cotton and rice, with annual average s of 20,000 lbs and 10,000 lbs of active ingredient (lbs a.i.) applied , respectively (representing 43% an d 22% of the total use on agricultural crops , respectively ). The crop with the highest average percent crop treated with carfentrazone

- ethyl is caneberries (65%), followed by hops (60%). Estimates of non

- agricultural uses are not readily available.

Acco rding to the United States Geological Survey‟s national pesticide usage data (based on information from 1999 to 2004), an average of 96,439 lbs of carfentrazone

- ethyl per year are applied nationally to agriculture in the United States (see Figure 3.1 ). Ba sed on these data, approximately 35 % of the average pounds of carfentrazone

- ethyl used per year is applied to corn, approximately 34 % is applied to rice , and 29 % is applied to cotton

.

### 11

F IGURE 3.1. Estimated Us ag e of Carfentrazone

- ethyl (USGS, 2010).

3.2. Environmental Fate and Transport

Carfentrazone

- ethyl [e thyl α,2

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoate ; CAS No. 128639

- 02

- 1 ; PC code 128712] is the ethyl ester of carfentrazone (CAS No. 128621

- 72

- 7 ), which is its chloropropionic acid (chemical names and structures are provided in Appendix B ). Carfentrazone

- ethyl readily hydrolyzes to carfentrazone via aerobic microbial metabolism and alkaline hydrolysis (anaerobic microbial metabolis m is uncertain). Carfentrazone, however, is not readily biodegraded and is stable to hydrolysis. Aqueous photolysis may be a dominant route of degradation of carfentrazone in clear, shallow waters (photolysis on soil is uncertain) . Additional major rout es of dissipation of carfentrazone include leaching and runoff , due to its mobility in soil . Environmental fate and transport properties of carfentrazone

- ethyl and carfentrazone are summarized in Tables 3. 2 and 3. 3 , respectively.

### 12

TABLE 3. 2

. General Physi cal/Chemical Properties and Environmental Fate Parameters of Carfentrazone

- ethyl.
Parameter Value Reference Physical/Chemical Parameters

Molecular mass 412.20 g/mol (Calculated) Water solubility 12 mg/L (20°C) 22 mg/L (25°C)

MRID 43939203 Vapor pressure 5.4 x 10 - 8 torr (20°C) 1.2 x 10 - 7 torr (25°C)
Octanol

- water partition coefficient (K OW ) 2.3 x 10 3 (log K OW = 3.36)

Henry‟s Law constant 2.4 x 10 - 9 atm·m 3 /mol (20°C) 3.0 x 10 - 9 atm·m 3 /mol (25°C)
Octanol

- air partition coefficient (K OA ) 2.3 x 10 10 torr (20°C) 1.9 x 10 10 torr (25°C) (Calculated from P/C properties) Dissociation constant (pKa) No dissociation MRID 43939203
Persistence in Water Hydrolysis half

- life No evidence of degradation (pH 5) 8.6 d (pH 7) 2.8 hrs (pH 9) MRID 43189231

Aqueous photolysis half

- life 9.5 d MRID 44934201 Aerobic aquatic metabolism half

life 2.3 hrs (clay loam sediment; pH 7.3

- 8.1) 2.7 hrs (silty clay loam sediment; pH 5.1

- 7.7) MRID 44419016

Persistence in Soil

Aerobic soil metabolism half

- life 12 ± 13 d (loamy sand; pH 4.5) 1.0 ± 0.1 d (Speyer 2.2 loamy sand; pH 5.8) 0.10 ± 0 d (silt loam; pH 5.6) 0.12 ± 0.01 d ( sandy clay loam; pH 5.7) MRID 44165034

Mobility No acceptable soil mobility data because compound is not stable in soil.

Bioconcentration

Fish bioconcentration factor 49 (edible), ≤413 (inedible), ≤186 (whole fish) MRID 44165042 Field Dissipation Terrestrial field dissipation DT 50 2 d (KS sand) 5 d (MN silt loam) (Parent detected ≤20 cm deep.) (MRID 44165039) A

Intervals were in ad equate to establish a half

- life ( NC sandy loam ) 1 d ( IA clay loam) (Parent detected ≤10 cm deep.) MRID 44419017

Aquatic field dissipation DT 50 5 d (CA rice water; pH 7.3) 2 d (LA rice water; pH 6.1) (MRID 44654701) B

0.3 d (6.2 hrs; FL pond; pH 7.9) MRID 46253901

A Study results are uncertain because the analytical method used was not independently validated.
B Study results are uncertain because storage stability data were not provided.

### 13 Mobility

C arfentrazone

- ethyl is soluble in water up to 22 mg/L (at 25°C; MRID 43939203). V olatilization into air will b e limited

, with a relatively low vapor pressure (1.2 x 10 - 7 

### torr at 25°C) and Henry‟s Law Constant (3.0 x 10 - 9 

### atm·m 3 

### /mol at 25°C). EpiSUITE (v4.0) estimates a half

- life in air of 51 hours for carfentrazone

- ethyl, which indicates that any volatilized residues will persist in air, which may result in long

- range transport. However, long

- range transport of carfentrazone

- ethyl is not an exposure route of concern due to the compound‟s low volatility and low persistence in most environments following deposition from the air

. The mobility of carfentrazone

- ethyl in soil could not be measured due to its rapid degradation in soil.

The octanol

- water (K OW 

### ) and octanol

- air (K OA 

### ) partition coefficients of carfentrazone

- ethyl (2.3 x 10 3 

### and 1.9 x 10 10 

### , respectively) were sufficiently high to investigate the compound‟s bioaccumulation potential. However, fish bioconcentration factors are ≤413, indicating th at bioaccumulation of carfentrazone

- ethyl residues is not a primary concern in aquatic organisms (MRID 44165042). C arfentrazone

- ethyl is not expected to bioconcentrate in terrestrial organisms either due to its low bioconcentration in aquatic organisms an d its low expected availability to terrestrial organisms due to its non

- persistence in most environments

.

Degradation

Carfentrazone

- ethyl rapidly hydrolyzes in alkaline water ( half

- life of 2.8 hours at pH 9) and readily hydrolyzes in neutral water (half

- life of 8.6 days at pH 7)

. There is no evidence of degradation by hydrolysis in acidic water (pH 5; MRID 43189231). The compound is readily microbially metabolized in aerobic environments, with half

- lives in soi l ranging from 0 .1 0 to 21 days ( mean of 3.2±7.2; MRID 44165034) and half

- lives in water of 2.3 to 2.7 hours (MRID 44419016). The degradation half

- lives in water, however, may have been shortened by instability during sample processing and any storage prio r to analysis. They also may reflect chemical hydrolysis as well as biodegradation since water pH values were up to 7.7 and 8.1 on study intervals when the test compound was detected ; however, this is uncertain because degradation rates were similar betwee n systems of predominantly acidic and alkaline pH

. T he bio degradation half

- lives in soil and water only describe the initial degradation kinetics of carfentrazone

- ethyl since the degradation kinetics were biphasic over time and not first

- order. Low level s of the compound (generally less than 10% of the applied in soil and less in water ) persisted over the duration of the studies

. The biodegradation of carfentrazone

- ethyl in anaerobic environments is uncertain because a cceptable anaerobic biodegradation d ata have not been submitted

.

Carfentrazone

- ethyl undergoes aqueous photolysis, with a half

- life of 9.5 days (MRID 44934201). However, b iodegradation and any neutral to alkaline hydrolysis

, rather than photolysis, are expected to dominate degradation.

T ransformation Products

The primary degradate of carfentrazone

- ethyl is carfentrazone ( i.e. , carfentrazone acid, the chloropropionic acid of carfentrazone

- ethyl; 

### chemical names and structures are provided in Appendix B ) . Carfentrazone formed up to 99.7% of the applied radioactivity (% AR) by 14 days

### 14

after treatment and was stable at each pH in the submitted hydrolysis study of the 

### ethyl ester (MRID 43189231). Carfentrazone also formed up to 90% AR (1.3 days after treat ment) and 80% AR (1 or 7 days after treatment) in the submitted aerobic soil metabolism and aerobic aquatic metabolism studies of the ethyl ester, respectively. Carfentrazone was persistent in some aerobic soils, with half

lives of 31, 101, and 286 days ( MRID 44165034 ), and persistent in some aerobic 

### aquatic systems as well , with half

- lives of 39 and 72 days in a submitted study of the ethyl ester (MRID 44419016

, study in review ). A review from the European Commission (2003) indicates that carfentrazone i s persistent in anaerobic environments as well, with a DT 50 

### greater than 100 days. Photolysis may be an important route of dissipation for carfentrazone, with half

- lives in water of 5.4 to 10 days reported in the European Commission (2003) review.

As an anion (pKa 

### of 2.66 ; Kemikalie

- inspektionen, 2008 ), carfentrazone is mobile, with 

### soil

- water partition coefficients (K d 

### ) ranging from 0.39 to 1.3 L/kg in five soils (MRID 43189233). Partitioning to soil was not correlated with the soil‟s fraction of organi c carbon. 

### Carfentrazone, as an anion, will not bioconcentrate in aquatic or terrestrial organisms.

Physicochemical properties of carfentrazone are uncertain. Studies have not been submitted or located on the water solubility, vapor pressure, octanol

- wat er partition coefficient, or dissociation constant of carfentrazone. Estimates from EpiSUITE are uncertain, as the model was not designed to be accurate for ionic compounds. For example, EpiSUITE (v4.0) estimates a log K OW 

### of 3.48 for carfentrazone, which is inaccurate ( i.e. , too high) for an anion. Values of log K OW 

### for carfentrazone reported by some secondary sources ( e.g. , Kemikalie

- inspektionen

, 2008) appear to be similarly inaccurate at acidic pH values

. Table 3. 3 su mmarizes reported environmental fate and transport properties of carfentrazone.

TABLE 3. 3

. General Physical/Chemical Properties and Environmental Fate Parameters of Carfentrazone Acid

. Parameter Value Reference A Physical/Chemical Parameters
Molecular mass 384.14 g/mol (C alculated) Dissociation constant (pKa) 2.66 (temperature not reported) Kemikalie

inspektionen , 2008
Persistence in Water Hydrolysis half

- life N o evidence of degradation (pH 5)

N o evidence of degradation (pH 7) N o evidence of degradation (pH 9) MRID 4 3189231

Aqueous photolysis half

- life 5.4

- 10.4 d European Commission, 2003 Aerobic aquatic metabolism half

- life 39 d (silty clay loam sediment) 72 d (clay loam sediment) MRID 44419016

Persistence in Soil
Aerobic soil metabolism half

life 30.9 d (Speyer 2.2 loamy sand) 101 d (UK clay loam) 286 d (US Cosad loamy sand) MRID 44165034

A na erobic soil metabolism DT 50 >100 d (Speyer 2.2 loamy sand) European Commission, 2003

### 15

Parameter Value Reference A Mobility
Soil

- water partitioning coefficient (K d ) 0.39 (CA loamy sand; 0.23% o.c.) 1.05 (UK sandy clay loam; 3.4% o.c.) 1.11 (Speyer 2.2 loamy sand; 2.3% o.c.) 1.28 (NY loamy sand; 1.9% o.c.) 1.32 (UK silt loam; 2.7% o.c.) MRID 43189233

A Sources with no MRID have not been reviewed by the Agency.



### Other major degradates of carfentrazone

- ethyl in aerobic soil include its cinnamic acid (up to 51% AR at 33 days), its propionic acid (up to 23% AR at 270 days), its benzoic acid (up to 22% AR at 365 days), 3

- hydroxymethyl

- F8426

- benzoic acid (up to 24% AR at 365 days), and an unidentified compound, Unknown 7 (up to 18% AR at 365 days; MRID 44165034). In aerobic aquatic systems, the only major degradate of carfentrazone

- ethyl other than carfentrazone acid was its cinnamic acid (up to 11% AR at 21 days); MRID 44416016, study in review). Major photolytic degradates of carfentrazone

- ethyl included α,2,4

- trihydroxy

- F8426 (up to 18% AR at 15 days), α

- hydroxymethyl

- 2,4

- dihydroxy

- F8426 (up to 15% AR at 15 days), and α

- hydroxy

F8426 (up to 12% AR at 8 days; MRID 449 34201). Major photolytic degradates of carfentrazone acid are uncertain because acceptable aqueous photolysis data on carfentrazone have not been submitted. Carbon dioxide and other volatile compounds formed no more than 4.6% AR in any submitted study of carfentrazone

- ethyl.

The cinnamic acid, propionic acid, and benzoic acid of carfentrazone

- ethyl were persistent in aerobic soils, with respective half

- life ranges of 65

- 430 days, 56

- 370 days, and 420

- 3300 days (MRID 44633504). All of these acids were mo bile in soil, with respective Freundlich K OC 

### value ranges of 44

- 333 L/kg OC 

### (cinnamic acid), 27

- 260 L/kg OC 

### (propionic acid), and 4

- 41 L/kg OC 

### (benzoic acid; MRID 44165036). The mobility in soil of 3

- hydroxymethyl

- F8426

- benzoic acid was shown to be high, wit h Freundlich K OC 

### values ranging from <0.3 to 9 L/kg OC 

### (MRID 44165037).

In summary, nine major degradates of carfentrazone

- ethyl have been identified in submitted studies. Six degradates, including carfentrazone acid, form in aerobic soil. Three degradat es are photoproducts that are not expected to be prominent in the environment due to biodegradation and alkaline hydrolysis processes dominating the degradation of carfentrazone

- ethyl.

4. Receptors

Consistent with the process described in the Overview Do cument 5 

### , the risk assessment for carfentrazone

- ethyl will rely on a surrogate species approach. T oxicological data generated from surrogate test species, that are intended to be representative of broad taxonomic groups, are used
to e xtrapolate to potential effects on a variety of species (receptors) included under these taxonomic groupings.

5 Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs. Office of Prevention, Pesticides, and Toxic Substances. Office of Pesticide Programs. Washington, D.C. January 23, 2004

.

### 16

A cute and chronic toxicity data from studies submitted by pesticide registrants along with the available open literature are used to evaluate the potential direct and indirect effects of carfentrazone

- ethyl on aquatic and terrestrial receptors. Toxicity studies for the technical g rade active ingredient (TGAI) and the typical end

- use product (TEP) will all be considered in the ecological risk assessment. O pen literature studies are identified using EPA‟s ECOTOX database 6 

### that employs a literature search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife. R esearch papers accepted into the ECOTOX database are screened using standard procedures to ensure consistent, high quality informa tion; these studies will be considered during the „Analysis‟ phase of risk assessment process. The Ecological Incident Information System (EIIS, version 2.1 7 

### ) that tracks incident reports submitted to EPA and the Avian Monitoring Information System (AIMS 8 

### ) will be used to identify supportive, line of evidence information on exposure of aquatic and terrestrial receptors. Data from all of these sources can also provide insight into the direct and indirect effects of carfentrazone

- ethyl on biotic communities from loss of species that are sensitive to the chemical.

4.1. Aquatic and Terrestrial Effects

Effects on Aquatic Organisms

A cute aquatic toxicity data are available for carfentrazone

- ethyl ; however, chronic toxicity data are incomplete, lacking freshwa ter life

- cycle and saltwater early life

- stage studies , which are needed due to potential direct application to water

. Moreover , c arfentrazone

- ethyl ‟s mode

- of

action (previously described) as a protoporphyrinogen oxidase inhibitor

, raises substantial concerns for its LDPH toxicity to aquatic organisms

. Table 4.1 provides a summary of the most sensitive data from taxonomic groups and the surrogate species used to characterize potential acute and chronic aquatic effects of carfentrazone

- ethyl

. A list of all submitted studies to date is found in Appendix A

.

TABLE 4.1

. Aquatic toxicity profile for Carfentrazone

- ethyl

Taxon Exposure

Duration Guideline Most Sensitive Species Tested Toxicity Value Acute Toxicity Category 1 MRID

Freshwater Fish and Aquatic

Phase Amphibians Acute 850.1075 Rainbow trout Oncorhynchus mykiss LC 50 = 1.6 mg

a.i. /L using TGAI (91.7% a.i.) Moderately

Toxic 43189228

Chronic 850.1400

850.1500 Rainbow trout

ELS 2 Test

Rainbow trout Life Cycle Test NOAEC = 118

μg a.i./L LOAEC = 242 μg a.i./L 3

-- 4 NA 44424201

--

6 http://www.epa.gov/ecotox
7 http://www.epa.gov/oppefed1/general/databasesdescription.htm
8 American Bird Conservency database, http: //www.abcbirds.org/

.

### 17

Taxon Exposure

Duration Guideline Most Sensitive Species Tested Toxicity Value Acute Toxicity Category 1 MRID

LDPH 5 Study No

Guidelines (modified 850.1400) Rainbow trout

Rainbow trout NOAEC = < 16.4

μg a.i./L LOAEC = 16.4 μg a.i./L 6

NOAEC = 22 μg a.i./L LOAEC = 45 μg a.i./L 7 NA 44963201 No NOAEC, dosing and dissolved oxygen problems.

46037001 Does not meet requirement for an LDPH study.

Estuarine/ Marine Fish Acute 850.1075 Tidewater silverside Menidia beryllina LC 50 = 1.14 mg

a.i./L using TGAI (90.3 % a.i.) Moderately

Toxic 44165005

Chronic 850.1400

- - No Data

-- --

Freshwater Invertebrates Acute 850.1010 Water flea Daphnia
magna EC 50 = >9.8 mg

a.i./L Moderately

Toxic 43189230

850.1735 Invertebrate

Sediment Test No Data

-- --
Chronic 850.1300 Water flea

-- NA

--

Estuarine/ Marine Invertebrates Acute Mysid shrimp Mysidopsis bahia LC 50 = 1.16 mg

a.i./L Moderately

Toxic 44165003

850.1740 Invertebrate

Sediment Test No Data

-- --
Chronic 850.1350

-- No Data NA

--

Vascular plant Tier I and

Tier II 8 850.4400 Duckweed ( Lemna gibba ) EC 50 = 5.9 μg ai/L;
NOAEL = 2.2 ppb NA 43849603

Non

vascular plant Tier I and

Tier II 8 850.5400 Freshwater diatom ( Navicula pelliculosa ) EC 50 = 6.5 μg

ai/L
NOAEL = 1.9 ppb NA 43849605

1 Categories of acute toxicity for aquatic organisms based on LC 50 (mg/L): < 0.1 very highly toxic; 0.1

- 1 highly toxic; >1

- 10 moderately toxic; >10

- 100 slightly toxic; >100 practically nontoxic.
2 ELS = early life

- stage 3

. Based on significant reductions in total length and wet weight of juvenile fish.
4 Missing Data.
5 LDPH = Light

- Dependant Peroxidizing H erbicide ; Data Call In, GDCI 128712

- 26285, required FMC to submit a fish early life

- cycle study (OPPTS guideline 850.1400) for carfentrazone

- ethyl under ultraviolet light conditions. Though study is underway, d ata have not yet been submitted; therefore, a data gap still exists DCI 128712

- 26285.
6 Based on significant reductions in wet weight at lowest test concentration; length and survival also reduced at 34.6 μg ai/L.
7 Based on larval survival, length at day 58 and terminal growth (length, wet weight, and dry weight)
8 Guideline specifies that if 50% effect is exceed ed in Tier I, then Tier II data are also required

.



### The LC 50 

### was 1.6 mg a.i./ L for rainbow trout using te chnical grade carfentrazone

- ethyl (MRID 43189228 ). For estuarine/marine fish, the tidewater silverside LC 50 

### was 1.14 mg a.i./L

, also using technical grade (MRID 44165005). In an early life

- stage study rainbow trout had

### 18

significant reductions in total length and wet weight of juvenile fish at a concentration of 242 μg a.i./L (NOAEC = 118 μg a.i./L; MRID 44424201 ) under standard test conditions. However, attempts made to estimate the LDPH enhanced toxicity were unsuccessf ul (MRIDs 44963201 and 46037001 ). In the former study (MRID 44963201 ) , dissolved oxygen problems were cited. The latter study (MRID 46037001 ) was initially classified as acceptable and later downgraded to supplemental for qualitative use because the ligh ting was not deemed adequate for an LDPH study ; however this study did add a line of evidence showing that the LDPH toxicity appears to be o n the order of five to ten times greater . The NOAEC for rainbow trout was <16.4 μg a.i./L ( 44963201 )

, but no endpoi nts were confirmed for use in risk assessment. This is a data gap.

Acute toxicity data are required per 40 CFR Part 158.630 for fish and aquatic invertebrates for all terrestrial and aquatic uses. Since carfentrazone

- ethyl converts rapidly, 2.3

- 2.7 h, into carfentrazone acid, which has an aerobic aquatic half

- life of 39

- 72 d, data on carfentrazone acid acute toxicity to fish and aquatic in vertebrates will also be assessed. With the exception of saltwater fish and mollusk toxicity data, most of the needed data are available; see section below where the information is presented by taxonomic group. Acute saltwater fish and oyster shell

depos ition studies with carfentrazone acid are needed; these are data gap s

.

Since carfentrazone

- ethyl may be directly applied to water, chronic toxicity data are required for both fish and aquatic invertebrates, both freshwater and saltwater. Though the aerobic aquatic half

- life is 2.3

- 2.7 h (MRID 44419016) , no acceptable anaerobic aquatic data are available and so, the persistence of carfentrazone

- ethyl in anaerobic aquat ic environments is unknown. The compound hydrolyzes quickly (t 1/2 

### of 2.8 hrs) in alkaline waters and is stable in acidic waters

. The main degradate, carfentrazone acid ( Table 3.3 

### ), has a n aerobic aquatic metabolism t 1/2 

### of 39

- 72 d. Because the pesticide may be applied directly to water and the estimated environmental concentration (EE C

, 12 μg a.i. /L f rom use as an aquatic herbicide ) is ≥ 

### 0.1 of the fish early life

stage study (NOAEC = 118 μg a.i./L; MRID 44424201 or <16.4 μg a.i./L from LDPH toxicity, MRID 44963201 ) , the requirement for a fish life

- cycle study is triggered using a freshwater fish species

. A freshwater invertebrate life

- cycle test using the TGAI is required for all terrestrial and aquatic uses. Since, however, the acid form is expected to be the dominant form after a few hours, this test is requested using carfentrazone acid, in lieu of parent. A fish early life

- stage study and an invertebrate life

- cycle study are both required for saltwater species due to the potential for direct application to saltwater

. These studies should be conducted using species for which acute data are available

. Chronic fish and aquatic invertebrate studies should be conducted using the degradate, carfentrazone acid 

### , since this is the form expecte d in chronic aquatic exposure.

Acute s ediment toxicity tests for freshwater and saltwater invertebrates are needed since :

the soil

- water partition coefficient is unknown due to rapid degradation of the parent compound, and so the half

- life for the parent plus acid is not a primary

concern , even though the anaerobic aquatic half

- life has not been determined ; and the Koc is unknown; however, if it does hydrolyze to the acid quickly in aerobic and anaerobic water bodies, then the Koc of the acid woul d be more relevant. Being an ion, the acid is m obile to highly mobile with Koc value s ranging from 6.3 to 48 L/kg

.

### 19

The core issue is whether the residues will partition to sediment. The parent's Kow is slightly greater than 1000, so it triggers acute se diment tox icity studies . B ut it is expected to be very short lived. The acid, on the other hand, will not primarily partition to sediment. Therefore, even though the acid may persist, it does not trigger the chronic sediment toxicity study because it wi ll not partition to sediment. The parent half

- life is <10 d in soil ( aerobic aquatic half

- life 2.3

- 2.7 h

, MRID 44419016) suggesting the need for acute, rather than chronic, sediment data. Therefore, acute sediment tox icity studies are needed for the pare nt only.

Carfentrazone

- ethyl was very highly toxic to aquatic plants (EC 50 

### = 6.5 μg a

. i

. /L for a diatom and 5.9 μg a

. i

. /L for duckweed).

Data are available to assess toxicity to four degradation products [ F8426

- cinnamic acid, carfentrazone ( F8426

- chloropropionic acid )

, F8426

- benzoic acid and F8426

- proprionic acid ]

. These data are presented below by taxonomic group of test organisms

.

Fish and Aquatic

- Phase Amphibians

Since LC 50' 

### s for the parent compound ( Table 4.1 ) fall in the range of >1 to 10 p pm, carfentrazone

- ethyl is classified as moderately toxic to freshwater and saltwater fish on an acute basis. Rainbow trout toxicity studies with four degradation products of carfentrazone

- ethyl show that they are all slightly to practically nontoxic to f ish ( Table 4.2 ). Degradates tested were less toxic than parent to fish on an acute basis.

TABLE 4.2 . Acute Toxicity of Degradation Products of Carfentrazone

- ethyl to the Rainbow Trout

Degradation product % ai 96

- hour LC 50 

### (ppm) Toxicity

Category MRID No.

Author/Year Study

Classification

F4826

– chloropropionic acid (carfentrazone acid) 99.0 >99.2 Slightly toxic to Practically nontoxic 44165015 Acceptable

F4826

- benzoic acid 99.0 >92.5 Slightly toxic to Practically nontoxic 44165009 Acceptable

F4826

– cinnamic acid 96.6 >25.4 Slightly toxic to Practically nontoxic 44176105 Acceptable

F4826

– proprionic acid 98.6 >95.6 Slightly toxic to Practically nontoxic 44165013 Acceptable



### Aquatic I nvertebrates

Since LC 50' 

### s for the parent compound ( Table 4.1 ) fall in the range of >1 to 10 ppm, carfentrazone

- ethyl is classified as moderately toxic to aquatic invertebrates on an acute basis. Daphnid toxicity studies with four degradation products of carfentrazone

- ethyl show that they are all slightly to practically nontoxic to freshwater invertebrates ( Table 4.3 )

. Similarly, one test conducted with the mysid with one degradate shows it to be slightly to practically nontoxic.

### 20

Therefore, degradates tested were less toxic than parent t o aquatic invertebrates, both freshwater and saltwater, on an acute basis.

TABLE 4.3 . Acute Toxicity of Degradation Products of Carfentrazone

- ethyl to the Waterflea and the Mysid

Degradation product % ai 96

- hour EC50 (ppm) Toxicity

Category MRID No. Study Classification

Waterflea (

Daphnia magna )

F4826

– chloropropionic acid (carfentrazone acid) 99.0 >101 Practically nontoxic 44165016 Acceptable

F4826

– benzoic acid 99.0 >92.8 Slightly toxic to Practically nontoxic 44165007 Acceptable

F4826

– cinnamic acid 96.9 >10.7 Slightly toxic to Practically nontoxic 44176103 Acceptable

F4826

– proprionic acid 98.6 >102 Practically nontoxic 44165011 Acceptable 

### Mysid ( Mysidopsis bahia )

F4826

– chloropropionic acid (carfentrazone acid) 99.0 >99.2 Slightly toxic to Practically nontoxic 44165015 Acceptable



### Aquatic Plants Aquatic plant and algae testing is required for any herbicide that has outdoor non

- residential terrestrial uses that may move off

- site by runoff (solubility >10 ppm in water), by drift (aerial or irrigation), or that is applied directly to aquatic use sites (except residential). Results of Tier II toxicity testing show that technical carfentrazone

- ethyl exhibits considerable toxicity to aquatic plants, algae, and blue

- green algae ( Table Error! Reference source not found. 4.1 ). The most sensitive aquatic plant tested is the vascular plant duckweed (EC 50 

### = 5.9 μg a

. i

. /L). The freshwater diatom is also highly sensitive to carfentrazone

- ethyl (EC 50 

### = 6.5 μg a

. i

. /L).

TABLE 4.4 . Acute Toxicity of Degradation Products of Carfentrazone

- ethyl to Freshwater Green Algae (

Pseudokirchneria subcapitata , formerly Selenastrum capricornutum ).

Degradation product % ai EC 50 

### (ppb) NOAEL

(ppb) MRID No.

Author/Year Study

Classification
F8426

- Chloropropionic Acid (carfentrazone acid) 98.6 534 405 44165014 Supplemental 1

F8426

- Benzoic Acid 98.6 12,600 2,700 44165006 Supplemental 1

F8426

- Cinnamic Acid 98.6 26.2 8.46 44176102 Supplemental 1

F8426

- Propionic Acid 98.6 139 100 44165010 Supplemental 1

1 Only 72 h; G uideline 850. 5 400 specifies 1 20 h, but otherwise, scientifically sound. 

### Selenastrum capricornutum

### 21

Algal toxicity studies with four degradation products of carfentrazone

- ethyl show a broad range of toxicity to algae ( Table 4. 4 ) , all less toxic than parent

. Even though the se studies were classified as supplemental, due to the short test duration (72 h, rather than the guideline requirement of 120 h), they can be compared to parent toxi city at 72 h by using MRID 44419005 (s ee Table 7.6 ) , since this study also had only 72 h duration. This study showed parent to be more toxic than either degradate with a 72

- h EC 50 

### of 12.7 μg ai/L (as compared to 26.2

- 12,600) and NOAEC of 8.15 μg ai/L (as compared to 8.46

- 2700). Cinnamic acid was the most toxic degradation product to green algae , with toxicity approximately half that of the parent based on EC 50 

### results, but very close based on the no

- effect level.

Effects on Terrestrial Organisms

Laboratory and field toxicity studies are available for characterization of the effects of carfentrazone

- ethyl to birds (also surrogate for terrestrial

- phase amphibians and reptiles) and mammals. Table 4.5 provides a summary of the most sensitive species tested for each terrestrial taxonomic group; see Appendix A for a complete list of submitted studies to date.

TABLE 4 .5

. Terrestrial toxicity profile for carfentrazone

- ethyl

Taxon Exposure

Duration Guideline Most Sensitive Species Tested Toxicity Value Acute Toxicity Category MRID

Mammals Acute 850.2400 Norway Rat Rattus norvegicus LD 50 = >5000

mg/kg bw Practically

Nontoxic 43189207

Chronic 870

- 3800

( 83

- 4 two gen

. repro

. ) Norway Rat NOAEL = 142 mg/kg/d ( 1500 ppm) LOAEL = 387 mg/kg/d for females (4000 ppm) 1 NA 44165026

Birds, Reptiles and Terrestrial

Phase Amphibians Acute Oral 850.2100 Northern Bobwhite Colinus virginianus

Passerine LD 50 = >2250 mg

ai/Kg bw

, NOAEL = 810 mg/kg bw 2

Data Gap Practically

Nontoxic

-- 43189225

--

Sub

- acute Dietary 850.2200 Northern bobwhite
and
Mallard duck Anas platyrhynchos L C 50 = >5620 mg ai/kg NO A EC = 5620 mg ai/ kg 3 Practically

Nontoxic 43189226

43189227

Chronic Reproduction 850.2300 Mallard duck NOAEC = 1000 mg ai/kg LOAEC = > 1 0 00 mg ai/ kg 4 NA 44419003

Terrestrial Invertebrates Acute 850.3020 Honey Bee Apis mellifera LD 50 = > 27.9 μg

a.i./bee, NOAEC = 27.9 μg a.i./

bee 5 Prac t ically

Nontoxic 44 633502

### 22

Taxon Exposure

Duration Guideline Most Sensitive Species Tested Toxicity Value Acute Toxicity Category MRID

Non

guideline Earthworm,

Eisenia foetida EC 50 >820 = m g

ai/kg

, NOAEC = 820 m g ai/kg Prac t ically Nontoxic 44176101

Terrestrial Plants Tier I I Plant

Studies with TGAI 850.4100

Seedling Emergence Monocot:

Onion Allium cepa

Dicot: Cabbage Brassica oleraceae EC 25 = >0.009 lb

a.i./A , NOAEC = 0.002 lb a.i./ A 6

EC 25 = 0.0 1 7 lb a.i./A

, NOAEC = 0.007 lb a.i./ A 7 NA 43939204

850.4150 Vegetative Vigor Monocot:

Onion

Dicot: Tomato
Solanum esculentum EC 25 = 0.012 lb

a.i./A , NOAEC = 0.00 6 lb a.i./A 8

EC 25 = 0.0012 lb a.i./A , NOAEC = 0.0006 lb a.i./A NA 43892716

1 Based on decreased pup body weights in both sexes of the F2 generation
2 The NOEL of 810 mg/kg is based upon the slight reduction in body weight gain noted among birds at the 1350 and 2250 test levels.
3 No effects seen at the highest concentration tested.
4 No observed reproduction impairment at the highest concentration tested.
5 No observed reproduction impairment at the highest concentration tested.
6 Based on shoot weight.
7 Based on shoot length
8 Based on weight.



### Acute toxicity to terrestrial animals is categorized using the classification system shown in Table 4.6 ( US EPA, 2004). Toxicity categories for terrestrial plants have not been defined.

TABLE 4.6

. Categories of Acute Toxicity for Avian and Mammalian Stud ies
Toxicity Category Oral LD 50 Dietary LC 50 Very highly toxic < 10 mg/kg < 50 ppm Highly toxic 10

- 50 mg/kg 50

- 500 ppm Moderately toxic 51

- 500 mg/kg 501

- 1000 ppm Slightly toxic 501

- 2000 mg/kg 1001

- 5000 ppm Practically non

- toxic > 2000 mg/kg > 5000 ppm



### Mammals, Birds, Terrestrial

- Phase Amphibians and Reptiles

Carfentrazone

- ethyl is categorized as practically nontoxic toxic to birds (surrogate for terrestrial

phase amphibians and reptiles ) , mammals

, and terrestrial insects on an acute basis (LD 50 

### = >5000 mg a

. i

. /kg and >2250 mg a

. i

. / k g based on body weight of the rat and quail; respectively

, and >200 mg/bee; MRIDs 43189207, 43189225 and 44176108 ). Acceptable acute avian oral toxicity data have not been submitted for a passerine species, which is now required under the 40 CFR Part 158 (2008) data requirements for conventional pesticides.

### 23

Carfentrazone

- ethyl affect ed mammalian development, causing decreased pup body weights in both sexes of the F2 genera tion in a two

- generation reproduction study with the rat at a dietar y concentration of 1500 ppm (MRID 4416526)

.

Two avian subacute dietary toxicity studies were submitted , one with Northern bobwhite (MRID 431892 26) and on e with mallards (MRID 431892 27). Both studies found the dietary LC 50 

### to be >5620 mg a

. i

. /L. Both studies show that carfentrazone

- ethyl is practically nontoxic to birds on a subacute basis.

Results of avian reproduction studies using the TGAI showed that dietary concentrations up to 10 00 ppm caused no observed reproduction impairment in either quail or mallards

. D ietary exposure to 1000 ppm caused reduction in body weight in adult bobwhite. Results were uncertain in the bobwhite reproduction study due to problems with health of test birds, but results are sufficient to conclude that use of carfentrazone

- ethyl has low chronic toxicity to birds. Therefore, this study does not need to be repeated. Based on the application rates approved for carfentr azone

- ethyl, EECs are not expected to approach levels that showed potential effects in the reproduction toxicity studies.

Terrestrial Invertebrates

A honey bee acute contact study was performed using TGAI ( 92.2 % a

. i

. ) resulting in 48

- h acute contact LD 50 

### of > 27.9 μg a.i./bee (MRID 44633502

, Table 4.5 ). This study was classified as

a cceptable

, indicating that carfentrazone

- ethyl is practically nontoxic to terrestrial invertebrates

. 9



### Earthworm subchronic (14

- d) toxicity tests are available for the pare nt compound and four degradates ( Table 4.7 ). No significant effects were seen at the top test concentration, which was 1000 mg a.i./kg in all studies. The differences in EC 50 

### s and NOAELs represents mean measured concentrations in all except MRID 44176104 (data is not available for measured concentrations in this study). These studies indicate that carfentrazone

- ethyl and its major degradates are practically non

- toxic to earthworms.

TABLE 4.7

. Acute Toxicity of Degradation Products of Carfentrazone

- ethyl to Earthworm s , (

Eisenia foetida )

. Degradation product % ai EC 50 

### (pp m ai) NOAEL

(pp m ai) MRID No.

Author/Year Study

Classification
F4826

– cinnamic acid 96.9 >1000 1 1000 1 44176104 Supplemental 2

F4826

– chloropropionic acid (carfentrazone acid) 99.0 >756 756 44165017 44409007 Supplemental 2

F4826

– benzoic acid 99 >753 753 44165008 44419009 Supplemental 2

F4826

– proprionic acid 98.6 >846 846 44165012 44419008 Supplemental 2

1 No measured concentrations were reported in this study, 1000 mg ai/kg was the top nominal concentration in all studies presented in this table; therefore, cinnamic acid is not necessarily less toxic than the other degradates or parent, this inf ormation is needed to be able to make a comparison.
2 No approved guideline currently exists f or this study, but otherwise, it is scientifically sound.

9 http://www.epa.gov/oppefed1/ecorisk_ders/toera_analysis_eco.htm

### 24 Terrestrial Plants (Guideline 850.4100 and 850.4150) using TEP

For effects on seedling emergence, onion wa s the most sensitive species with an EC 25 

### of >0.009 lb a

. i

. /A and a NOAEL of 0.00 2 lb a

. i

. / A. . For effects on vegetative vigor, tomato wa s the most sensitive species with an EC 25 

### of 0.0012 lb a

. i

. /A and an NOAEL of 0.0006 lb a

. i

. /A. Available terrestrial plant toxicity studies were classified supplemental because the test substance was technical product ; guidelines require that plant testing be conducted using a typical enduse product, TEP. The proposed rule establishing use of the TEP for vegetative vigor and seedling emergence studies states, “The TEP that contains the highest percent age of active ingredient, and/or is the most commonly used, would be required. ” (FR Vol. 70 No. 47; March 11, 2005; 12289). Tier II seedling emergence and vegetative vigor studies on all plants tested (see Tables 4.8 and 4.9 ) should be repeated using TEP. This is a data gap.

TABLE 4.8 . Seedling emergence toxicity of nontarget terrestrial plant (Tier II)

Species % ai EC 25 

### (lb ai/A) NOAEL (lb ai/A)
Corn (monocot) 91.7 >0.063 0.063
Onion (monocot) 91.7 >0.009 0.002
Ryegrass (monocot) 91.7 >0.063 0.063
Wheat (monocot) 91.7 >0.063 0.063
Cabbage (dicot) 91.7 0.022 0.007
Cucumber (dicot) 91.7 >0.063 0.021
Lettuce (dicot) 91.7 0.026 0.006
Radish (dicot, root crop) 91.7 0.023 0.007
Tomato (dicot) 91.7 0.037 0.021
Soybean (dicot) 91.7 >0.063 0.063

TABLE 4.9. Vegetative vigor toxicity of nontarget terrestrial plant (Tier II)

Species % ai EC 25 

### (lb ai/A) NOAEC (lb ai/A)
Corn (monocot) 91.7 >0.063 0.063
Onion (monocot) 91.7 0.012 0.006
Ryegrass (monocot) 91.7 >0.063 0.063
Wheat (monocot) 91.7 >0.063 0.063
Cabbage (dicot) 91.7 0.0019 0.0005

### 25

TABLE 4.9. Vegetative vigor toxicity of nontarget terrestrial plant (Tier II)

Species % ai EC 25 

### (lb ai/A) NOAEC (lb ai/A)
Cucumber (dicot) 91.7 0.0025 0.0008
Lettuce (dicot) 91.7 0.0023 0.0004
Radish (dicot, root crop) 91.7 0.0027 0.0004
Tomato (dicot) 91.7 0.0012 0.0006
Soybean (dicot) 91.7 >0.019 0.006

The potential for e ffects to non

- target plants ha s been demonstrated in the field ( see Section 4.2. Incident Database Review below) although the magnitude is uncertain

.
4.2. Incident Database Review

A n incident review was made on October 27, 2010 by querying the Ecological Incident Information System (EIIS, version 2.1) and the Avian Montoring Information System (AIMS ), for more information, see Receptors section, above. R eported ecological incidents from the EIIS database associated with the use of carfentra zone

- ethyl are summarized in Table 4. 10 ; no bird incidents were found in the AIMS database

.

TABLE 4. 10 . Summary of Reported Incidents Involving Carfentrazone

- ethyl

Taxon Number of Incidents Involving Carfentrazone

- ethyl

Registered Use/Misuse, (Undetermined) Likelihood,

Highly Probable Likelihood,

P robable Likelihood,

Possible Likelihood,

Not Likely

Terrestrial Vertebrates 0/0

- 0

- - 0

- - 0

- - 0

- Terrestrial Invertebrates 0/0

- 0

- - 0

- - 0

- - 0

- Terrestrial Plants 2 / 6 (2) 3 2 3 2
Aquatic Animals 0/0

- 0

- - 0

- - 0

- - 0

-

Ten incidents involving carfentrazone

- ethyl have been reported so far, seven in Washington and three in California. All reported incidents involved plant damage; no animal incidents have been reported. The two incidents ( I014796

- 001 and I014796

- 002 ) from registered use of carfentrazone

- ethyl were both from use on sweet corn in 2003 , and involved extensive damage (145 and 515 acres, respectively); however, both were determined “not likely” to have been caused by carfentrazone

- ethyl

. T hese two i ncident s , submitted by EPA Region 10

, w ere from Dept. of Agriculture, State of Washington from investigation s of damage to corn. In both cases, Atrazine 4F ( I014796

- 002 report merely specifies Atrazine) , Outlook and Aim (active ingredient

### 26

is car fentrazone

- ethyl) were applied in accordance with l abel s . Laboratory analysis in both

cases , however, did not detect any of the ingredients applied. Investigators speculated that there was an adverse reaction from Outlook to the variety of sweet corn gro wn, caused by weather and irrigation conditions for the crop. Laboratory analysis also showed MCPA residues (another herbicide) , which was allegedly not applied at the time of the incident but is not normal ly found long after an application

. Two incidents classified as “highly probable” for attribution to carfentrazone

- ethyl were both due to misuses, one intentional (I0210998

- 028). Of the two incidents classified “probable,” one was deemed accidental (I020725

- 055), but one was undetermined (I 019519

- 043), and therefore, may have been due to a registered use; both of these occurred in California. Similarly, of the
t hree incidents classified as “possible” two w ere determined to be from misuse (one accidental) of carfentrazone

- ethyl, while the le gality of use for the other was undetermined, and therefore, may have been due to a registered use. Overall, available incident data indicate that exposure pathways for carfentrazone

- ethyl are complete and that exposure levels may be sufficient to result in field

- observable effects.

4.3. Ecosystems Potentially at Risk

Carfentrazone

- ethyl may be applied as an aerial or ground spray herbicide to terrestrial habitats for agricultural uses, and as a spot treatment for non

- agricultural and residential areas o r directly
to water

. The ecosystems potentially at risk are often extensive in scope; therefore, it may not be possible to identify specific ecosystems during the development of a nation

- wide ecological risk assessment. However, in general terms, terrest rial ecosystems potentially at risk could include the treated field and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or gr asslands, woodlands, riparian habitats, and other uncultivated areas. Due to the persistence of carfentrazone

- ethyl, it is expected to drift and/or runoff due to application to food crops, resulting in possible exposure to aquatic ecosystems. Aquatic ecos ystems potentially at risk due to the use of carfentrazone

- ethyl include water bodies adjacent to, or downstream from, the treated field and might include impounded bodies such as ponds, lakes and reservoirs, or flowing waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also includes marine ecosystems, including estuaries. When applied directly to water, aquatic animals and plants, as well as shoreline terrestrial plants, are at risk.

5. Assessment Endpoints

Assessment endpoints are defined as “explicit expressions of the actual environmental value that is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the valued attributes of the environment that are considered to be at risk; and 2) operationally defining the assessment endpoint in terms of an ecological entity ( i.e ., a community of fish and aquatic invertebrates) and its attributes ( i.e ., survival and reproduction). Therefore, se lection of the assessment endpoints is based on valued entities (i.e., ecological receptors), the ecosystems potentially at risk, the migration pathways of pesticides, and the routes by which ecological receptors are exposed to pesticide

- related contaminat ion. The selection of clearly defined assessment endpoints is important because they provide direction and boundaries in the risk

### 27

assessment for addressing risk management issues of concern. Changes to assessment endpoints are typically estimated from th e available toxicity studies, which are used as the measures of effects to characterize potential ecological risks associated with exposure to a pesticide, such as carfentrazone

- ethyl

. In its ecological risk assessments, the Agency does not routinely incl ude an evaluation of mixtures of active ingredients, either those mixtures of multiple active ingredients in product formulations or those in the applicator‟s tank. In the case of the product formulations of active ingredients (that is, a registered produ ct containing more than one active ingredient), each active ingredient is subject to an individual risk assessment for regulatory decision regarding the active ingredient on a particular use site. If effects data are available for a formulated product

con taining more than one active ingredient, the data may be used qualitatively or quantitatively in accordance with the Agency‟s Overview Document and the Services‟ Evaluation Memorandum (USEPA, 2004 and USFWS/NMFS/NOAA , 2004).

Available toxicity data for en vironmental mixtures of carfentrazone

- ethyl with other pesticides will be presented as part of the ecological risk assessment. It is expected that the toxic effect of carfentrazone

- ethyl , in combination with other pesticides used in the environment, is likely to be a function of many factors including but not necessarily limited to: (1) the exposed species, (2) the co

- contaminants in the mixture, (3) the ratio of carfentrazone

- ethyl and c o

- contaminant concentrations, (4) differences in the pattern and duration of exposure among contaminants, and (5) the differential effects of other physical/chemical characteristics of the receiving waters ( e.g. organic matter present in sediment and suspe nded water). Quantitatively predicting the combined effects of all these variables on mixture toxicity to any given taxa with confidence is beyond the capabilities of the available data and methodologies. However, a qualitative discussion of implications of the available pesticide mixture effects data on the confidence of risk assessment conclusions will be addressed as part of the uncertainty analysis.

Carfentrazone

- ethyl is a triazolinone herbicide that belongs to the mode

- of

- action group E/14 that inh ibits the enzyme protoporp hyrinogen oxidase (PPO ). This class of herbicides is referred to as light

- dependen t peroxidizing herbicides (LDPH ), which have enhanced toxicity in the presence of solar ultraviolet light. LDPHs target PPO specifically , which is present in the heme and chlorophyll biosynthetic pathways of animals and plants, respectively. Inhibition of PPO in animals and plants leads to an accumulation of phototoxic heme and chlorophyll precursors called protoporphyrins, which, in the presence o f ultraviolet light, produce activated oxygen radicals that can rapidly disrupt cellular function via oxidative damage to cell membranes . Some chemicals in this class have also been associated with peroxisome proliferation, which can induce hepatocellular carcinomas in rodents. (Smith and Elcombe 1989, Ashby et al. as cited in Krijt et al. 1999). Other example registered herbicides in this group include oxyfluorfen, acifluorfen, lactofen, nitrofen, and fomesafen.

To estimate exposure concentrations, the ecological risk assessment considers applications at maximum rates. If multiple applications are allowed, the maximum amount per application and minimum interval between applications are used

– provided that maximum total annual application amounts are a lso included in this configuration. Several EFED exposure models ( e.g. , PRZM

- EXAMS, T

- REX) are used to estimate likely high

- end exposure to carfentrazone

-

### 28

ethyl . The most sensitive toxicity endpoints are used from surrogate test species to estimate
treatment

- related direct effects on acute mortality and chronic reproductive, growth and survival assessment endpoints. Toxicity tests are intended to determine effects of pesticide exposure on birds, mammals, fish, terrestrial and aquatic invertebrates, and plants. These tests include short

term acute, sub

- acute, and reproduction studies and are typically arranged in a hierarchical or tiered system that progresses from basic laboratory tests to applied field studies. The toxicity studies are used to eva luate the potential of a pesticide to cause adverse effects, to determine whether further testing is required, and to determine the need for precautionary label statements to minimize the potential adverse effects to non

- target animals and plants.

6. Conceptual Model

For a chemical to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathway is the means by which a pesticide moves in the envir onment from a source to an ecological receptor. For an ecological exposure pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposur e.

A conceptual model provides a written description and visual representation of the predicted relationships between carfentrazone

- ethyl, potential routes of exposure, and the predicted effects for the assessment endpoint. A conceptual model consists of two major components: risk hypothesis and a conceptual diagram (USEPA, 1998).

6.1. Risk Hypothesis

Risk hypotheses are specific assumptions about potential adverse effects ( i.e. , changes in assessment endpoints) and may be based on theory and logic, empirical data, mathematical models, or probability models (USEPA

, 1998). For this assessment, the risk is stressor

- initiated, where the stressor is the release of carfentrazone

- ethyl into the environment. The following risk hypotheses are presumed for this screening

- level assessment:

Carfentra zone

- ethyl

, when used in accordance with registered labels, will lead to of f

- site movement of the compound’s residues via runoff, spray drift, and eroded soil leading to
exposure of nontarget plants and animals Based on information on the environmental fate, mode of action, direct toxicity

, and potential indirect effects of the compound’s residues

, the registered uses of carfentrazone

- ethyl cause reduced survival, growth, and
repr oduction to non

- target terrestrial and aquatic animals and plants.

Carfent razone

- ethyl, when applied directly to water in accordance with current labels, will result in exposure of non

- tar get aquatic plants and animals, which will result in adverse effect s upon the survival, growth, and/or reproduction of non

- target aquatic animals and plants.

### 29

6.2. Conceptual Diagram

The conceptual site model is a generic graphic depiction of the risk hypothesis, and assumes that the herbici de, carfentrazone

- ethyl, having multiple outdoor agricultural and non

- agricultural uses, is capable of affecting aquatic and terrestrial animals provided that environmental concentrations are sufficiently elevated as a result of proposed label uses. Based on an examination of the physicochemical properties of carfentrazone

- ethyl, the fate and disposition in the environment, and mode of application, a conceptual model was developed that represents the possible relationships between the stressors, ecological receptors, and the assessment endpoints. Through a preliminary iterative process of examining available data, the conceptual model ( i.e

., the representation of the risk hypothesis) may be refined to reflect the likely exposure pathways and the organisms that are most relevant and applicable to this assessment (see Figure 6.1 and Figure 6. 2 below). They include the parent compound , or stressor (carfentrazone

- ethyl ) , the

sources, transport pathways, exposure media and exposure points, biological receptor types

, and attribute changes.

In order for a chemical to pose an ecological risk, it must reach ecological receptors in biologically significant concentrations. An exposure pathw ay is the means by which a pesticide moves in the environment from a source to an ecological receptor. For an ecological exposure pathway to be complete, it must have a source, a release mechanism, an environmental transport medium, a point of exposure for ecological receptors, and a feasible route of exposure. In addition, the potential mechanisms of transformation (as well as which transformation products may form in the environment, in which media, and how much) must be understood, especially if the chem ical‟ s transformation products are of greater toxicological concern than the parent compound. In this case

, only the parent compound is examined, since major degradates are less toxic than parent. The assessment of ecological exposure pathways, therefore , includes an examination of the source and potential migration pathways, and the determination of potential exposure routes for carfentrazone

- ethyl

. Under the possible uses of carfentrazone

- ethyl, the sources and mechanisms of release of the compound are from ground or aerial spray applications to agricultural and non

- agricultur al areas

. Surface runoff from the areas of application is assumed to depen d on factors such as topography, irrigation, and rainfall events. Direct deposition may result in contamination of food items that may be consumed by terrestrial organisms. Spray drift results in contaminated adjacent areas, including bodies of water. A s mentioned in Section 3 above, carfentrazone

- ethyl‟s tendency to move from soil to surface water is unknown and it has little tendency to leach to ground water due to its quick degradation to carfentrazone acid . Due to the low potential for volatilizati on, atmospheric transport of carfentrazone

- ethyl is unlikely.

For aquatic receptors, the major point of exposure is through direct contact with the water column, sediment, and pore water (gill/ integument) contaminated from either direct application,
spra y drift (from spray application)

, and/or runoff from treated areas. Indirect effects to aquatic organisms (both fish and aquatic invertebrates) can also occur through impact to various food chains (bioaccumulation/ bioconcentration). The representative a quatic receptors are certain freshwater and estuarine/ marine fish, invertebrates, and, in certain cases, aquatic plants. The major point of exposure for terrestrial animals is consumption of food contaminated with

### 30

residues such as grass, foliage, and sma ll insects. For plants, the point of exposure is direct contact or root uptake. The representative terrestrial receptors are mammals, birds and terrestrial plants. The attribute changes used to assess risk to terrestrial receptors depend on the type of test ( e.g. , reduced survival, growth, or reproduction for animals and seedling emergence and vegetative vigor for plants). It should be noted, that these species do not cover all the possible species in the animal and plant kingdoms; certain taxa are cons idered as surrogates for other taxa. For example, fish may be considered surrogates for aquatic phase amphibians.

This conceptual model also shows details about biomagnification for a chemical (see piscivorous birds and mammals in ( Figure 6.1 ). Carfentr azone

- ethyl has a log K OW 

### and log K OA 

### (2.3 x 10 3


### and 1.9 x 10 10 

### , respectively) that indicate that bioconcentration in aquatic and terrestrial organisms should be investigated . However, fish bioconcentration factors are ≤413, indicating that carfentrazone

- ethyl residues will not bioconcentrate in aquatic organisms (MRID 44165042). And the compound is not expected to be available to bioconcentrate in terrestrial organisms due to its non

- persistence and its low bioconcentration observed in aquatic organisms.

FIGURE 6.1

. Conceptual model depicting stressors, exposure pathways, and potential effects to aquatic organisms from the use of carfentrazone

- ethyl on agricultural and certain

non - agricultural sites

. Dotted lines indic ate exposure pathways that have a low likelihood of contributing to ecological risk. **Route of exposure includes only ingestion of fish and aquatic inverts. 

### Stressor

Source

Receptors

Attribute Change Carfentrazone

- ethyl applied to agricultural or non

- agricultural use site

Direct Application or Spray drift

Aquatic animals Invertebrates Vertebrates **Piscivorous mammals and birds

Individual organisms Reduced survival Reduced growth Reduced reproduction Food chain Reduction in algae and vascular plants Reduction in prey availability Habitat integrity Reduction in primary productivity Reduced cover Surface water/ Sediment Runoff

Aquatic Animals Invertebrates Vertebrates 

### Exposure Media

Uptake/gills

or integument



### Ingestion Ingestion Atmospheric transport

Wet/dry deposition Soil Leaching to

Groundwater

Uptake/gills

or integument

Aquatic Plants

Non

- vascular Vascular Uptake/cell, roots, leaves Riparian plants terrestrial exposure pathways; see Figure 6.1b

### 31

FIGURE 6.2

. Conceptual model depicting stressors, exposure pathways, and potential effects to terrestrial organisms from the use of carfentrazone

- ethyl on agricultural and certain non

- agricultural sites

. Dotted lines indicate exposure pathways that have a low likelihood of co n tributing to ecological risk.

Drinking water exposure of carfentrazone

- ethyl to avian and mammalian species will be screened to determine if this is a potential pathway of concern. The Screening Imbibition Program (SIP v.1.0, Released Jun. 15, 2010) will be used to calculate an upper bound estimate of exposure using carfentrazone

- ethyl‟s solubility, the most sensitive acute and chronic avian toxicity endpoints, and the most sensitive acute and chronic mammalian toxicity endpoints.

7. Analysis Plan

In registration review, pesticide ecological risk assessments will follow the Agency‟s Guidelines for Ecological Risk Assessment, will be in compliance with the paper titled “Overview of the Ecological Risk Assessment Process in the Office of Pesticide Programs, U.S. Environmental Protection Agency” (USEPA, 2004), and will be done in accordance with Section 7 of the Endangered Species Act. Stressor

Source

Attribute Change Carfentrazone

- ethyl applied to agricultural or non

- agricultural terrestrial use site

Direct application Spray drift

Terrestrial vertebrates Terrestrial invertebrates

Individual organisms Reduced survival Reduced growth Reduced reproduction Food chain Reduction in prey and food Habitat integrity Reduction in primary productivity Reduced cover Terrestrial plants grasses/ forbs, fruit, seeds (trees, shrubs) Runoff

Terrestrial vertebrates 

### Exposure Media & Receptors Soil

Ingestion Ingestion Ingestion Dermal uptake/Ingestion Atmospheric transport

Root uptake/contact

Wet/dry deposition

Ingestion Leaching to

Groundwater Irrigation water

### 32

Previously completed screening level risk assessments and exceedances of Agency levels of concern indicate a need t o further examine and refine risk. Analysis of potential indirect effects on listed species is also required. This analysis plan will be revisited and may be revised depending upon the data available in the open literature and the information submitted b y the public in response to the opening of the Registration Review docket.

Use information will be retrieved from registration labels and used as inputs for estimating exposure concentrations from the various use scenarios. Carfentrazone

- ethyl ‟s use patt erns suggest potential risk concerns to aquatic and terrestrial organisms. The range of potential exposure to carfentrazone

- ethyl to non

- target terrestrial organisms can vary on application method (aerial or ground), application rate, and use pattern.

7.1. Stressors of Concern

The focus of this assessment is solely on carfentrazone

- ethyl because ecotoxicity data indicate that carfentrazone acid and other transformation products are much less toxic to aquatic organisms than the parent compound . Toxicit y data on pesticide mixtures (products containing multiple active ingredients) and environmental mixtures of carfentrazone

- ethyl with other pesticides (those mixtures occurring in the environment following application), if available, may be discussed as pa rt of the ecological risk assessment. Carfentrazone

- ethyl may be applied in tank mixtures with other products approved for use on registered crops. It is expected that the toxic effect of carfentrazone

- ethyl , in combination with other pesticides used in the environment, is likely to be a function of many factors including, but not necessarily limited to: (1) the exposed species, (2) the co

- contaminants in the mixture, (3) the ratio of carfentrazone

- ethyl and

co

- contaminant concentrations, (4) differences in the pattern and duration of exposure among contaminants, and (5) the differential effects of other physical/ chemical characteristics of the receiving waters ( e.g. organic matter present in sediment and suspended water). Quantitatively predicting the c ombined effects of all these variables on mixture toxicity to any given taxa with confidence is beyond the capabilities of the available data and methodologies. However, a qualitative discussion of implications of the available pesticide mixture effects d ata on the confidence of risk assessment conclusions will be addressed as part of the uncertainty analysis.

7.2. Measures of Exposure

In order to estimate risks of carfentrazone

- ethyl exposures in aquatic and terrestrial environments, all exposure modeling and resulting risk conclusions will be made based on maximum application rates for the current use patterns. Measures of exposure are based on aquatic and terrestrial models that pr edict estimated environmental concentrations of carfentrazone

- ethyl using maximum labeled application rates and methods, as well as any mitigation measures specifically indicated on the label. The models used to predict aquatic 1

- in

10 year EECs are the T ier I Rice Model and the Tier II coupled models Pesticide Roo t Zone Model and EX posure Analysis Model System (PRZM/EXAMS). The model used to predict terrestrial exposure is T

- REX. The model used to derive EECs relevant to terrestrial and wetland plants i s TerrPlant

. These models are parameterized using relevant reviewed registrant

submitted environmental fate and transport data.

### 33

PRZM (v.3.12.2, May 12, 2005) and EXAMS (v.2.98.4.6, April 25, 2005) are the current screening simulation models coupled with the graphical user interface, PE ( v5.0, November, 2006 ) to generate daily exposures and 1

- in

- 10 year EECs of carfentrazone

- ethyl that may occur from spray drift and runoff to surface water bodies adjacent to application sites. PRZM simulates pesticide app lication, movement and transformation on an agricultural field and the resultant pesticide loadings to a receiving water body via runoff , erosion and spray drift. EXAMS simulates the fate of the pesticide and resulting concentrations in the water body. T he standard scenario used for ecological pesticide assessments assumes application to a 10

- hectare agricultural field that drains into an adjacent 1

- hectare water body that is 2 meters deep (20,000

m 3 

### volume) with no outlet. The composite model PRZM/ EXAMS is used to estimate screening

level exposure of aquatic organisms to stressors.

The Tier I Rice Model (v1.0; May 8, 2007) relies on an equilibrium partitioning concept to provide conservative estimates of EECs resulting from application of pesticides to rice paddies. When a pesticide is applied to a rice paddy, the model assumes that it will instantaneously partition between a water phase and a sediment phase. The model does not account for pesticide degradation, mass transfer between the aqueous phase and the sediment, volatilization, dilution, or other dissipation processes. The Tier I Rice Model was calibrated to generate estimates that are consistent with or conservative for dissolved concentrations measured within rice paddies and in discharged pad dy water. The model was not evaluated or calibrated for concentrations measured in sediment and does not account for residue s bound to suspended sediment. The Tier I Rice Model may be provisionally refined to account for degradation, as was done in a rec ent drinking water exposure assessment (DP 384371; USEPA, 2011).

The measure of exposure for aquatic species is the 1

- in

- 10 year return peak or rolling mean concentration. The 1

- in

- 10 year peak is used for estimating acute exposures of direct effects to aquatic organisms. The 1

- in

- 10

- year 60

- day mean is used for assessing chronic exposure to fish and aquatic

- phase amphibians. The 1

- in

- 10

- year 21

- day mean is used for assessing aquatic invertebrate chronic exposure.

Given the aquatic toxicity of carfentrazone

- ethyl

, its potential for direct application to water and the unknown degradation of parent under anaerobic conditions , the Agency will also consider the potential ex posures resulting from benthic/ sediment concentrations (EECs). Pore water

co ncentrations are commonly used to predict toxicity of non

- ionic substances in sediments and characterize exposure to organisms that spend time in or near sediments (Di Toro et al.

, 1991; USEPA

, 2002). PRZM/ EXAMS estimates 1

- in

- 10

- year peak and 21

- day mean EECs for pore
water.

Exposure estimates for terrestrial animals assumed to be in the target area are derived using the T

- REX model (version 1.3.1, 12/07/2006). For pesticides such as carfentrazone

- ethyl , which can be applied as a dust, this includes the amount of pesticide per square foot, used in LD 50 

### per square foot risk assessment calculations. EECs for terrestrial plants inhabiting dry and wetland areas are derived using TerrPlant (version 1.2.2, 12/26/2006). This model uses e stimates of pesticides in runoff and in spray drift to calculate EECs. EECs are based upon solubility, application rate and minimum incorporation depth.

### 34

7.3. Measures of Effect

Ecological effects data are used as measures of direct and indirect effects to biological receptors. Data are typically obtained from registrant

- submitted studies or from literature studies identified by ECOTOX. The ECOTOX database provides more ecological effects data in an attempt to bridge existing data gaps. ECOTOX is a sou rce for locating single chemical toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and Development, and the National Health and Environmental Effects Research Laboratory's Mid

- Continent Ecology Division.

The acute measures of effect used for animals in this assessment are the LD 50 

### , LC 50 

### and EC 50 

### for the most sensitive species measured for each assessed group

. The assessed grou ps are, freshwater fish, freshwater invertebrates, estuarine \ marine fish, estuarine/marine invertebrates, mammals, birds, terrestrial invertebrates, aquatic plants, and terrestrial plants. LD stands for "Lethal Dose", and LD 50 

### is the amount of a material, given all at once, that is estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” and LC 50 

### is the concentration of a chemical that is estimated to kill 50% of the test organisms. EC stands for “Effective Concentr ation” and the EC 50 

### is the concentration of a chemical that is estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic measures of exposure for listed and non

- listed animals are the NOAEL and NOAEC. NOAEL stands for “No Observed

Adverse

- Effect

- Level” and refers to the highest tested dose of a substance that has been reported to have no harmful (adverse) effects on test organisms. The NOAEC ( i.e. , “No

- Observed

Adverse

- Effect

- Concentration”) is the highest test concentrat ion at which none of the observed effects were statistically different from the control. For non

- listed plants, only acute exposures are assessed ( i.e. , EC 25 

### for terrestrial plants and EC 50 

### for aquatic plants); for listed plants either the NOAEC or EC 05 

### i s used.

Information on the potential effects of carfentrazone

- ethyl on non

- target animals is also collected from the Ecological Incident Information System (EIIS). The EIIS is a database containing adverse effect (typically mortality) reports on non

- targ et organisms where such effects have been associated with the use of pesticides. Information on incidents involving avian species is also provided through the Avian Monitoring Information System (AIMS), which is maintained by the American Bird Conservancy

.
Where available, sub

- lethal effects observed in both registrant

- submitted and open literature studies will be evaluated qualitatively. Such effects may include behavioral changes ( e.g. , lethargy and changes in coloration). Quantitative assessments of risks, though, are limited to those endpoints that can be directly linked to the Agency‟s assessment endpoints of impaired survival, growth and reproduction.

The assessment of risk for direct effects to non

- target organisms makes the assumption that the toxicity of carfentrazone

- ethyl to birds is similar to terrestrial

- phase amphibians and reptiles. The same assumption is made for fish and aquatic

- phase amphibians.

### 35

Several toxicity studies are needed to better assess the potenti al risk of carfentrazone

- ethyl
exposure to non

- target organisms, including : terrestrial plant toxicity studies using a TEP; passerine acute oral toxicity ; acute toxicity to mollusks using carfentrazone acid; chronic fish and aquatic invertebrate toxicity u sing carfentrazone acid ; acute sediment toxicity; and light

- dependent peroxidizing herbicide (LDPH) toxicity.

7.4. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects characterization to determine the potential ecological risk from the use of pesticides and the likelihood of direct and indirect effects to non

- target organisms in aquatic and terrestrial habitats. The exposure and toxicity effects data are integrated in order to evaluate th e risks of adverse ecological effects on

non

- target species. For the assessment of risks, the risk quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are divided by acute and chronic toxicity values. The resulting RQs ar e then compared to the Agency‟s Levels of Concern (LOCs) (USEPA

, 2004). These criteria will be used to indicate when carfentrazone

- ethyl ‟s uses, as directed on the label, have the potential to cause adverse direct or indirect effects to non

- target organis ms. In addition, incident data from the EIIS will be considered as part of the risk characterization.

7.5. Endangered Species Assessments

Consistent with the Agency‟s responsibility under the Endangered Species Act (ESA), the Agency will evaluate risks to Federally

- listed threatened and/or endangered (listed) species from registered uses of carfentrazone

- ethyl . This assessment will be conducted in accordance with the Overview Document (USEPA

, 2004), provisions of the ESA, and the Services‟ Endangered Sp ecies Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the registration of carfentrazone

- ethyl is based on an action area. The action area is considered to be the area directly or indirectly affected by the federal acti on, as indicated by the exceedance of Agency Levels of Concern (LOCs) used to evaluate direct or indirect effects. The Agency‟s approach to defining the action area under the provisions of the Overview Document (USEPA

, 2004) considers the results of the r isk assessment process to establish boundaries for that action area with the understanding that exposures below the Agency‟s defined LOCs constitute a no

- effect threshold. For the purposes of this assessment, attention will be focused on the footprint of the action ( i.e. , the area where carfentrazone

- ethyl application occurs), plus all areas where offsite transport may result in potential exposure that exceeds the Agency‟s LOCs. Specific measures of ecological effect that define the action area for liste d species include any direct and indirect effects and/ or potential modification of its critical habitat, including reduction in survival, growth, and reproduction as well as the full suite of sub

- lethal effects available in the effects literature. Theref ore, the action area extends to a point where environmental exposures are below any measured lethal or sub

lethal effect threshold for any biological entity at the whole organism, organ, tissue, and/ or

### 36

cellular level of organization. In situations where it is not possible to determine the threshold for an observed effect, the action area is not spatially limited and is assumed to be the entire United States.

Probit Analysis

Analysis of raw data from the aquatic acute toxicity studies for carfentrazone

- e thyl will be used to estimate probabilities of effects to aquatic and terrestrial animals. Slope estimates along with 95% conficence intervals will be used. When slope data is unavailable, a default slope of 4.5 is used with confidenct intervals of 2 and 9 ( Urban and Cook , 19 86 ).

7.6. Drinking Water Assessment

A drinking water assessment will be conducted to support future human health risk assessments of carfentrazone

- ethyl

. The drinking water assessment will incorporate model estimates of carfentrazone

- ethyl residues of concern in surface and ground waters. The MARC determined that the residues of concern in water are carfentrazone

- ethyl, its acid (carfentrazone) , and its cinnamic acid ( USEPA, 1998 a ). Concentrations in surface waters will be estimated using the Tier I model s FQPA Index Reservoir Screening T ool (FIRST, v.1.1.1, Dec. 18, 2007) and Tier I Rice Model (v1.0, May 8, 2007) followed, if necessary, by the Tier II linked models Pesticide Root Zone Model (PRZM v3.12.2, May 12, 2005) and EXposure Analysi s Modeling System (EXAMS v2.98.4. 6, Apr. 25, 2005 ). Ground water estimates of concentrations will be estimated using the Tier I model Screening Concentr ation in Ground Water ( SCI

- GROW v2.3, Jul. 29, 2003 ) followed by a higher tier mode l if necessary . The drinking water assessment will also include a summary of available surface and ground water monitoring data.

7.7. Endocrine Disruptor Screening Program

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor Screening Program (EDSP) to determine whether certain substances (including pesticide active and other ingredients) may have an effect in humans or wildlife similar to an eff ect produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator may designate.” The EDSP employs a two

- tiered approach to making the statutorily required determinations. Tier 1 consists of a battery of 11 screening as says to identify the potential of a chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal systems. Chemicals that go through Tier 1 screening and are found to have the potential to interact with E, A, or T hormonal s ystems will proceed to the next stage of the EDSP where EPA will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 testing is designed to identify any adverse endocrine related effects caused by the substance, a nd establish a dose

- response relationship between the dose and the E, A, or T effect.

Between October 2009 and February 2010, EPA issued test orders/data call

- ins for the first group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. This list of chemicals was selected based on the potential for human exposure through pathways such as food and water, residential activity, and certain post

- application agricultural scenarios. This list should not be construed as a list of known or likely endocrine disruptors.

### 37

Carfentrazone

- ethyl was not included in the list. Test orders were issued in November, 2009. Carfentrazone

- ethyl is not among the group of 58 pesticide active ingredients on the initial list to be screened under the EDSP. Under FFDCA sec. 408(p) the Agency must screen all pesticide chemicals. Ac cordingly, EPA anticipates issuing future EDSP test orders/data call

- ins for all pesticide active ingredients.

For further information on the status of the EDSP, the policies and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 scr eening battery, please visit our website: http://www.epa.gov/endo/.

7.8. Preliminary Identification of Data Gaps

The Agency needs additional environmental fate and ecological effects studies prior to conducting the planned assessments. Data gaps, uncert ainties and potential paths forward for the
assessment s of carfentrazone

- ethyl are described below.

7.8.1 . Environmental Fate

The studies submitted to fulfill environmental fate data requirements for carfentrazone

- ethyl are not sufficient for exposure assessment. The submitted anaerobic aquatic metabolism study was conducted on one soil with HPLC water ; pH and dissolved oxygen were not reported; and sampling intervals were inadequate to describe the decline of the paren t compound (MRID 44165035) . Therefore, a guideline

- compliant study is requested of acidic sediments and their associated waters.

Aqueous photolysis may be an important degradation route for carfentrazone acid. The submitted aqueous photolysis study on c arfentrazone acid was unacceptable because the sterility of the samples was not determined during the study and material balances were poor in some samples, showing a pattern of decline over time (MRID 44165032 ). Therefore, a new stud y is requested in ord er to describe the environmental fate of carfentrazone in clear, shallow, sun

- lit surface waters.

The submitted soil photolysis study of carfentrazone

- ethyl is unacceptable (MRID 44165033). However, this data gap does not need to be filled because biodeg radation rates are expected to outpace photolysis rates in soil. A column leaching study of carfentrazone

- ethyl is unacceptable (MRID 44165038) and a batch equilibrium study was not submitted. However, the compound is too short

- lived in soil to allow for a successful batch equilibrium study. Batch equilibrium data are available for the major identified degradates in aerobic soil, carfentrazone, F8426

- cinnamic acid

, F8426

- propionic acid

, F8426

- benzoic acid , and 3

- hydroxymethyl

- F8426

- benzoic acid (MRID 431 89233, 44165036, 44165037). Therefore, batch equilibrium data on carfentrazone

ethyl are not requested.

A submitted analytical method in soil ( MRID 44165040 and used in MRID 44165039 ) is upgradeable without an independent lab oratory validation (ILV) report . MRID 44165043 was submitted as an ILV for MRID 44165039 /44165040 . However, the method validated in MRID 44165043 was described in MRID 44419018 and not used in MRID 44165039. Therefore, the

### 38

analytical method in soil described in MRID 44419018 is acceptable, based on the ILV, and the terrestrial field dissipation study in MRID 44165039 is not acceptable ( i.e. , is upgradeable) without independent validation of the analytical method in soil used in the study (independent validation of analytical met hods used in field studies was required for studi es submitted on and after April 19, 1996, twelve months after publication of 60 FR 19589; Apr. 19, 1995). An ILV of the analytical method used in MRID 44165039 (MRID 44165040) is requested to support the fi eld dissipation study.

Frozen s torage stability data are needed to upgrade an aquatic field dissipation study ( MRID 44654701 ) to an acceptable classification. These data are requested.

Tables 7.1, 7.2, and 7.3 identify studies by M RID that offer data fo r each guideline requirement, as well as study classifications and whether or not further data are needed in or der to support risk
assessment . Draft Data Call

- In (DCI) tables for requested data are provided in APPENDIX C

.

TABLE 7.1. Submitted Environmen tal Fate Data for Carfentrazone

- ethyl.
Guideline Data

Requirement Submitted

Studies (MRID) Classification Data Needed ? Comments

835.2120 Hydrolysis 43189231 Acceptable No.

--

835.2240 Aqueous

photolysis 44165031 Unacceptable No.

--

44934201 Acceptable
835.2410 Soil photolysis 44 165033 Unacceptable Currently,

no. Biodegradation rates are expected to

outpace photolysis rates.
835.4100 Aerobic soil

metabolism 4 3189232 Upgradeable No.

--

44165034 Supp lemental
835.4200 Anaerobic soil

metabolism (None) (Not applicable) Currently,

no. These data are not expected to change

pending exposure assessments.
835.4300 Aerobic aquatic

metabolism 4 4419016 Supplemental No.

--

835.4400 Anaerobic aquatic

metabolism 44165035 Unacceptable Yes. A guideline

- compliant study conducted in acidic systems is requested.
835.1230 835.1240 Adsorption/

desorption and leaching 44165038 Una cceptable Currently,

no. Carfentrazone

- ethyl was too short

lived in soil to conduct a batch equilibrium study.
835.6100 Terrestrial field

dissipation 44165039 Upgradeable Yes. MRID 44165039 is upgradeable without independent validation of the analytical method in soil used in the study (MRID 44165040)

. MRID 44419017 may be upgradeable with acceptable soil characterization and storage stability data of sufficient duration. Submitted analytical methods are upgradeable if not independently validated. 44419017 Supplemental Storage stability 4 4165049 Acceptable Analytical method in soil 44 165040,

44165039 Upgradeable

44419018 (ILV: 44165043) Acceptable

### 39

Guideline Data

Requirement Submitted

Studies (MRID) Classification Data Needed ? Comments

835.6200 Aquatic field

dissipation 44419019 Unacceptable Yes. Frozen s torage stability data are needed to upgrade MRID 44654701 to an acceptable classification

. 44654701 Upgradeable
46253901 Supplemental Storage stability (None) (N/A) Analytical method in water 44165002 Acceptable

850

. 173 0 Fish BCF 44165042 Acceptable No.

--



### TABLE 7.2

. Submitted Environmental Fate Data for Carfentrazone Acid

. OCSPP Guideline Data

Requirement Submitted

Studies (MRID) Classification Data Gap? Comments

835.2240 Aqueous

photolysis 44165032 Unacceptable Yes. A guideline

- compliant study conducted in sterilized water is requested.
835.4100 Aerobic soil

metabolism 44633504 Supplemental No.

--

835.1230 835.1240 Adsorption/

desorption and leaching 43189233 Supplemental No.

--



### TABLE 7.3

. Submitted Environmental Fate Data for Degradates of Carfentrazone

- ethyl and Carfentrazone Acid

. OCSPP Guideline Data

Requirement Submitted

Studies (MRID) Classification Data Gap? Comments

835.4100 Aerobic soil

metabolism 44633504 Supplemental No.

--

835.1230 835.1240 Adsorption/

desorption and leaching 44165036 Supplemental No.

--

44165037 Supplemental



### 7.8 .2. Effects

Although many submissions have been made to provide data on the effects of carfentrazone

ethyl to aquatic and terrestrial organisms, data gaps still exist ( Tables 7.4

- 7. 6 ). Data gaps include the following: avian acute oral toxicity on a passerine species; terrestrial plant toxicity studies using a TEP; aquatic invertebrate life cycle toxicity; and full life

- cycle fish toxicity. These data gaps are discussed below.

### 40

TABLE 7. 4

. Available Ecological Effects Data for Aquatic Animals Exposed to Carfentrazone

- ethyl and Remaining Data Gaps.

Guideline Description MRID/ Accession Classification Data Gap? C omments

850.1010 Freshwater

invertebrates

– Acute toxicity 43189230 Acceptable

No --

44165004 Acceptable

45168001 In Review Mixture: Carfentrazone

ethyl/Metsulfuron

- methyl test.

850.1025 850.1035 Saltwater

invertebrates

– Acute toxicity 44165003 Acceptable Yes, mollusk data for carfentrazone acid --

850.1075 Freshwater fish

–

Acute toxicity 43189228 Acceptable No

--

43189229 Acceptable

850.1075 Saltwater fish

–

Acute toxicity 44165005 Acceptable Yes, for carfentrazone acid --

850.1300 Freshwater

invertebrate

– life cycle test 44419006 Invalid Yes Guideline

- compliant studies are requested for both freshwater and saltwater invertebrates, with carfentrazone acid.. 850.1350 Saltwater

invertebrates

– life cycle test -- -- Yes

850.1400 Freshwater fish

–

early life stage test 44424201 Acceptable No

--

850.1400 modified Light

- Dependent

Peroxidizing Herbicide (LDPH) Fish ELS Study 44963201 Supplemental

Yes Modified protocol : “Early Life

- Stage Toxicity Test with Fathead Minnow ( Pimephales promelas ) Under High Light Conditions Following FIFRA Guideline 72

- 4 and OPPTS Draft Guideline 850.1400 .” Protocol has been approved and study is in progress 46037001 Supplemental

850.1400 Saltwater fish

–

early life stage test -- -- Yes A guideline

- compliant study is requested using an estuarine/ marine fish (a species for which acute toxicity data are available) with carfentrazone acid.

850.1500 Fish life cycle test

-- -- Yes A guideline

- compliant study is requested using a freshwater fish (a species for which acute toxicity data are available) with carfentrazo ne acid.

### 41

Guideline Description MRID/ Accession Classification Data Gap? C omments

850.1735 Whole Sediment:

acute freshwater invertebrates -- -- Yes

--

850.1740 Whole Sediment:

acute marine invertebrates -- -- Yes

--



### TABLE 7. 5 . Available Ecological Effects Data for Terrestrial Animals Exposed to Carfentrazone

- ethyl and Remaining Data Gaps.

Guideline Description MRID/ Accession Classification Data Gap? Comments

850.2100 Avian acute oral

toxicity : Bobwhite quail

Passerine Species 43189225 Acceptable Yes A dosing study with a passerine species is now required (protocol to be submitted for approval)

.

-- --
850.2200 Avian sub

- acute

dietary toxicity :

Bobwhite quail

Mallard 43189226 Acceptable No --

43189227 Acceptable

850.2300 Avian

reproduction :

Bobwhite quail

Mallard 44419002 Supplemental No Quail study (44419002) was compromised by the death and injury of birds caused by a commotion but able to show no significant treatment

- related effects and does not have to be repeated. 44419003 Acceptable

850.3020 Honeybee acute

contact toxicity 44176108 Supplemental

No 44176108

- Study scientifically sound but only 24h; guideline specifies 48

- h. 24

- h NOAEL was 200 ug a.i./bee, highest level tested. 44633502 Acceptable

Non

Guidleline 14

- d Toxicity to

the Earthworm, Eisenia foetida 441650 08

Propionic Acid Supplemental

No 44165008, 44165012, 44165017, 44176101 and 44176104 were s upplemental because no approved guidelines

. This deviation do es not impact study results, data may be used in risk assessment.

For 44176101

, LC50 was 4441900 9 Addendeum to 44165008 with test concentration
measurements Supplemental

44165012 Proprionic Acid Supplemental

### 42

Guideline Description MRID/ Accession Classification Data Gap? Comments

44419008 Addendeum to 44165012 with test concentration
measurements Supplemental >820 mg ai/kg and NOAEC was 820 mg ai/kg (highest conc. tested)

– Tested on F8426 Technical (95.0% purity)

. Another study 44176104 was tested on F8426

- Cinnamic Acid (96.9% purity) and used nominal, rather than measured concentrations. The nominal

con centrations were the same and the results the same in that there were no effects in the highest treatment tested 1000 mg ai/kg. If these two studies were to be compared, measured concentrations would be needed for 44176104.

Addenda w ere sent ( 44419007, 4 4419008 and 44419009 ) which defined the highest test concentration s for 441650 08

, 44165012 and 44165017

, respectively, as 753, 846 and 756 mg ai/kg. 4416501 7 Chloropropionic Acid Supplemental

4441900 7 Addendeum to 44165012 with test concentration
measurements Supplemental

44176101 TGAI Supplemental

44176104 Cinn Acid Supplemental



### TABLE 7.6 . Available Ecological Effects Data for Plants Exposed to Carfentrazone

- ethyl and Remaining Data Gaps.

Guideline Description MRID Classification Data Gap? C omments

850.4100 Terrestrial Plant toxicity:

Tier I seedling emergence 43939204 Supplemental No These studies were originally classified as acceptable, but later downgraded to supplemental due to use of TGAI (F8426 Technical 91.7% purity), rather than the required TEP. Da ta on TEP toxicity to terrestrial plants is needed.

45626901 test with m ixture: Parent plus two metabolites.

44419005 had 72h duration, rather than guideline 120h, otherwise scientifically sound. 850.4100 Terrestrial Plant toxicity:

Tier 2 seedling emergence 43939204 Supplemental Yes, for TEP

850.4150 Terrestrial Plant toxicity:

Tier I vegetative vigor 43892716 Supplemental No

850.4150 Terrestrial Plant toxicity:

Tier 2 vegetative vigor 43939204 Supplemental Yes, for TEP 43892716 Supplemental

850.4400 Aquatic Plant Growth:

vascular plants 43849603 Acceptable No

45626901 In Review

850.5400 Aquatic Plant Growth: algae 43829717 Acceptable No

43849603 Acceptable

43849604 Acceptable

43849605 Acceptable

43849606 Acceptable

44419005 Supplemental

### 43

Acceptable acute toxicity studies were submitted for freshwater and saltwater fish ( MRIDs 43189228 and 44165005). Due to carfentrazone

- ethyl‟s previously recognized LDPH toxicity, a DCI was issued in 2006 (DCI 128712

- 26285 ) asking for a special LDPH study. However, attempts made to estimate the LDPH toxicity were unsuccessful (MRIDs 44963201 and 46037001 ) due to prob lems with dissolved oxygen and inadequate lighting. Although the toxicity appears to be on the order of five to ten times greater, no endpoints were confirmed for use in risk assessment. Since carfentrazone

- ethyl converts rapidly to carfentrazone acid ac ute data are also needed on this degradate ; data are available for rainbow trout (MRID 44165015 )

, daphnids and mysids (MRIDs 44165016 and 44165015 ) but not for saltwater fish or mollusks

. Th ese are data gap s

. One acceptable early life

- stage study is available for freshwater fish but no acceptable chronic toxicity data are available for estimating the chronic effects of carfentrazone

- ethyl or its acid to invertebrates , in freshwater or saltwater, by water column or sediment exposure

. Since carfentrazone

- ethyl may be applied directly to water, and the expected EEC is > 0.1 of the early life stage NOAEC for rainbow trout ( i.e. , <16.4 μg a.i./L, based on LDPH toxicity, MRID 44963201), chronic data are required per 40 CFR Part 158.630 . Chronic studies using saltwater fish and both freshwater and saltwater invertebrates are needed with carfentrazone acid due to the rapid conversion. Without this data, risk would have to be assumed but would not be quantifiable.

Acc eptable acute avian oral toxicity data were submitted for exposures of bobwhite quail and mallard duck to carfentrazone

- ethyl ; however, data are not available for passerines, which are required under the new 40 CFR Part 158 (Oct. 26, 2007) data requirement s for conventional pesticides (72 FR 60934; USEPA 2007 d ). The new Part 158 data requirements specify that acute avian oral toxicity data be submitted for either a mallard duck or bobwhite quail and a passerine species. Therefore, an avian oral toxicity t est (OCSPP Guideline 850.2100) is required for passerine birds, as specified in 40 CFR Part 158 (Oct. 26, 2007). EFED recommends that the Pesticide Re

- evaluation Division (PRD) request submission of a passerine study protocol for review by the Agency prio r to initiation of this study. If oral acute toxicity data are not submitted for passerines, EFED will assume acute risk for passerine species.

Studies submitted for terrestrial plants were originally categorized as acceptable, but later downgraded to su pplemental since they were conducted using TGAI, rather than TEP. Since guidelines specify the use of TEP, all plant species tested should be retested using TEP.

After evaluation of the available data for carfentrazone

- ethyl, the effects data gaps for registration review are (additional information is in Appendix C) :

Guideline Number : 850.1025, Oyster acute toxicity with carfentrazone acid. Guideline Number : 850.1075 , Fish acute toxicity (saltwater) with carfentrazone acid. Guideline Number: Both 850.1300 and 850.1350, Aquatic Invertebrate Life Cycle Toxicity ( freshwater and estuarine/marine) with carfentrazone acid

. Guideline Number: 850.1400, Early Life

- Stage Toxicity (saltwater fish) with carfentrazone acid.

### 44 Guideline Number: 850.1400 Using M odi fied Protocol f or Light

- Dependent Peroxidizing Herbicide (LDPH) ELS Toxicity (freshwater fish ) with TGAI. Guideline Number: 850.1500, Full Life Cycle Fish Test (freshwater) with carfentrazone acid

. Guideline Numbers: 850.1735 and 850.1740 , Acute Whole Sediment Toxicity with TGAI (freshwater and saltwater). Guideline Number: 850.2100, Study Title: Acute Avian Oral Toxicity Test using a Passerine species with TGAI

. Guideline Numbers : 850.4100 and 850.4150, Tier 2 Seedling Emergence and Veg etative Vigor with TEP

. Additional information can be found in Appendix C.

8. References

Di Toro, D. M., Zarba, C. S., Hansen, D. J., Berry, W. J. , Schwartz, R. C., Cowan, C. E. 1991. Technical basis for establishing sediment quality criteria for nonio nic organic chemicals using equilibrium partitioning. Environmental Toxicology and Chemistry, 10, 1541

- 1586.

European Commission. 2003. Review report for the active substance carfentrazone

- ethyl. European Commission, Health & Consumer Protection Direct orate

- General. April 10, 2003. Online at: http://ec.europa.eu/food/plant/protection/evaluation/newactive/list1

- 19_en.pdf

Kemikalieinspektionen (Swedish Chemicals Agency). 2008. Sammanställning av protokoll om riktvärden för växtskyddsmedel i ytvatten (Summary of minutes on benchmarks for pesticides in surface water). Kemikalieinspektionen, Bekämpningsmedel och biotekniska produkter. April 29 , 2008. Online at: http://www.kemi.se/upload/Bekampningsmedel/Vaxtskyddsmedel/Protokoll_riktvarden_vaxtskyddsmedel. pdf

Krijt, J., Stranska , P., Sanitrak, J., Chlumska, A., and Fakan, F. 1999. Liver preneoplastic changes in mice treated with the herbicide fomesafen. Hum. Exp. Toxicol. 18 : 338

- 344. (EcoReference No.: 95400)

Smith L.L. and C.R. Elcombe. 1989. Mechanistic studies and their role in the toxicological evaluation of pesticides. Food Addit. Contam. 6 Suppl. 1, pp. S57

- S65.

Urban, J.D., and N.J

. Cook. 1986. Ecological Risk Assessment: Standard Evaluation Procedures. Report No. EPA 540/9

- 85

- 001. U

. S

. Environmental Protection Agency, Hazard Evaluation Division, Washington, D.C. Available from NTIS (National Technical Information Service), Springfield, Virginia 22161, as PB 86

- 247

- 657.

U.S. Environmental Protection Agency (USEPA). 1998. Guidelines for Ecological Risk Assessment

, United States Environ mental Protection Agency, Washington, D.C.: Government Printing Office. Available at http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=12460 (Accessed June 19, 2009).

USEPA

. 1998 a

. Carfentrazone

- ethyl: Metabolism Asse ssment Review Committee (MARC) Memorandum. PP#7F4795. U.S. Environmental Protection Agency, Office of Pesticide Programs, Health Effects Division. Jun. 19, 1998.

USEPA. 2004

. Overview of the Ecological Risk Assessment Process in the Office of Pestic ide Programs, United States Environ mental Protection Agency, Washington, D.C.: Government Printing Office. Available at http://www.epa.gov/espp/consultation/ecorisk

- overview.pdf (Accessed June 19, 2009).

### 45

USEPA. 2010. Screening Level Us age Analysis (SLUA): Carfentrazone

- ethyl (128712)

. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention , Biological and Economic Analysis Division. Jul. 21, 2010

.
USEPA. 2011. Orrick, G. Carfentrazone

- ethyl: Drinking Water Expo sure Assessment of Proposed Label Amendments for Use on Rice

. DP barcode 384371. U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Environmental Fate and Effects Division. Memorandum to Health Effects Division and Registration Division. Feb. 16, 2011.

U.S. Fisheries and Wildlife Service and National Marine Fisheries Service ( US FWS/NMFS ). 1998

. Endangered Species Consultation Handbook: Procedures for Conducting Consultation and Conference Activities Under Sectio n 7 of the Endangered Species Act. Final Draft, United States Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS), Washington, D.C.: Government Printing Office. Available at http://www.fws.gov/endangered/consultations/s7hndbk/s 7hndbk.htm (Accessed June 19, 2009).

U.S. Fisheries and Wildlife Service, National Marine Fisheries Service and National Oceanic and Atmospheric Administration ( USFWS/NMFS/NOAA )

. 2004. 50 CFR Part 402. Joint Counterpart Endangered Species Act Section 7 Consultation Regulations; Final Rule. Federal Register Volume 69, Number 20, Pages 47731

- 47762. August 5, 2004.

U.S. Geological Survey (USGS). 2010

. 2002 Pesticide Use Maps. U.S. Geological Su rvey, National Water

Quality Assessment (NAWQA) Program, Pesticide National Synthesis Program. Accessed on Dec. 14, 2010 . Online at: http://water.usgs.gov/nawqa/pnsp/u sage/maps/compound_listing.php?year=02

SUBMI TTED ENVIRONMENTAL FATE STUDIES

MRID 43189231 Citation

Willut, J. (1993) Hydrolysis of F8426 at 25 degree C: Revised Report: Lab Project Number: 842E1193E1: P/2887. Unpublished study prepared by FMC Corp. 59 p.

43189232 Goodyear, A. (1994) (Carbon 14) F8426: Aerobic Soil Metabolism and Degradation: Final Interim

Report: Lab Project Number: 573/2: 573/ 2/1015: PC/0197. Unpublished study prepared by Hazleton Europe. 152 p.

43189233 Voelkl, S. (1994) Adsorption/D esorption of (carbon 14)

- F8426

- Chloropropionic Acid on Five Soils:

Lab Project Number: 346173: 842I3293E1: PC/0202. Unpublished study prepared by RCC Umweltchemie AG. 166 p.

44165002 Wenger, K. (1996) F8426 Technical: Analytical Method Validation in Filt ered and Unfiltered

Saltwater: Lab Project Number: V96

- 0046: J9602001D: FMC/SWMV/F8426. Unpublished study prepared by Toxikon Environmental Sciences. 32 p.

44165031 Willut, J. (1994) Photodegradation of (carbon 14)

- F8426 in Buffered Aqueous Solution at pH 5 by

Artificial Sunlight: Revised: Lab Project Number: P

- 2884: 842E1293E1. Unpublished study prepared by FMC Corp. 133 p.

44165032 Willut, J. (1995) Photodegradation of (carbon 14)

- F8426

- chloropropionic Acid in Buffered Aqueous

Solution by Simulated Sunlight: Lab Project Number: P

- 3051: 842E1294E1. Unpublished study prepared by FMC Corp. 175 p.

44165033 Willut, J. (1994) Photodegradation of (carbon 14)

- F8426 in Soil by Simulated Sunlight: Lab Project

Number: P

- 2915: 842E1393E1. Unpublished study prep ared by FMC Corp. 64 p.

44165034 Goodyear, A. (1995) (Carbon 14)

- F8426: Aerobic Soil Metabolism and Degradation: Final Report: Lab

Project Number: PC

- 0227: 842I2193E1: 573/2. Unpublished study prepared by Corning Hazleton Europe. 241 p.

### 46

44165035 Goodyear , A. (1995) (Carbon 14)

- F8426: Anaerobic Soil Metabolism and Degradation: Final Report:

Lab Project Number: PC

- 0241: 842I2594E1: 573/4. Unpublished study prepared by Corning Hazleton Europe. 128 p.

44165036 Gravelle, W. (1995) Adsorption/Desorption of (ca rbon 14)

- F8426

- benzoic Acid, (carbon 14)

- F8426

-

cinnamic Acid, and (carbon 14)

- F8426

- propionic Acid on Five Soils: Lab Project Number: P

- 3070: 842I3295E1. Unpublished study prepared by FMC Corp. 127 p.

44165037 Varanyak, L. (1996) Adsorption/Desorption of (carbon 14)

- F8426

- benzoic Acid on Five Soils: Lab

Project Number: P

- 3139: 842E3296E1. Unpublished study prepared by FMC Corp. 80 p.

44165038 Voelkl, S.; Morgenroth , U. (1995) Leaching Characteristics of Aged Residues of (carbon 14)

- F8426 in

Five Soils under Laboratory Conditions: Lab Project Number: PC

- 0210: 842I3193E1: 345284. Unpublished study prepared by RCC Umweltchemie AG. 223 p.

44165039 Jang, D. (1996) Terre strial Field Dissipation

-- Carfentrazone

- ethyl (F8426) 50 DF Herbicide: Lab

Project Number: RAN

- 0270: 842E4194E1. Unpublished study prepared by FMC Corp. 286 p.

44165040 Jang, D. (1996) Analytical Methodology for the Determination of Carfentrazone

- ethyl (F 8426) and Its

Metabolites in/on Bare Soil: Lab Project Number: RAN

- 0270M: 842E4194E1. Unpublished study prepared by FMC Corp. 101 p.

44165042 Schocken, M. (1995) F8426 Flow

- Through Bioconcentration and Metabolism Study with Rainbow

Trout (Oncorhynchus myk iss)...: Final Report: Lab Project Number: PC

- 0236: 94

- 8

- 5403: 842E5493E1. Unpublished study prepared by Springborn Labs, Inc. 179 p.

44165043 Bixler, T. (1996) Independent Method Validation: Determination of F8426 and Its Metabolites in/on

Soil: Lab Proj ect Number: RC

- 0058: 842MVL96R1: A005.005. Unpublished study prepared by Maxim Technologies, Inc. 87 p.

44165049 Starner, K. (1996) Cold Storage Stability of Significant F8426 Environmental Degradates on Soil:

F8426

- propionic Acid, F8426

- cinnamic Acid, F8 426

- benzoic Acid, and F8426

- chloropropionic Acid: Lab Project Number: RAN

- 0285: 842CSS95R1. Unpublished study prepared by FMC Corp. 104 p.

44419016 Elmarakby, S. (1997) Aerobic Aquatic Metabolism of (carbon 14)

- F8426: Lab Project Number:

842E2296E1: P

- 3266: F97092

- 801. Unpublished study prepared by FMC Corp. 194 p.

44419017 Schreier, T. (1997) Terrestrial Field Dissipation

-- F8426 50 DF Herbicide: Lab Project Number:

842E4195E1: RAN

- 0301. Unpublished study prepared by FMC Corp. 183 p.

44419018 Hubbar d, H. (1997) Analytical Methodology for the Determination of Carfentrazone

- Ethyl and its

Metabolites on Soil: Lab Project Number: RAN

- 0301M: 842E4195E1. Unpublished study prepared by FMC Corp. 49 p.

44419019 Summer, S.; Saxena, A. (1997) Carfentrazone

- eth yl (F8426) Herbicide

-- Aquatic Field Dissipation: Lab

Project Number: N002159A: 842E4296E1: PC

- 0281. Unpublished study prepared by Battelle. 185 p.

44633504 George, M. (1997) Aerobic Soil Degradation of the F8426 Acid Metabolites, F8426

- chloropropionic

aci d, F8426

- propionic acid, F8426

- cinnamic acid, and F8426

- benzoic acid: Lab Project Number: 842I2195E1: RAN

- 0276: 540W. Unpublished study prepared by FMC Corporation and PTRL West. 219 p.

44654701 Holihan, J. (1998) F8426 40 DF Herbicide

- Aquatic Field Dissipation: Lab Project Number:

842E4297E1: P

- 3311. Unpublished study prepared by FMC Corporation. 150 p.

44934201 Concha, M. (1999) Photodegradation of (carbon

- 14)F8426 in Buffered Aqueous Solution at pH 5 under

Artificial Light: Lab Project Number: 832 W: 842E1299E1: PC

- 0294. Unpublished study prepared by PTRL West, Inc. 128 p.

### 47

46253901 Dow, K. (2004) F8426 Aquatic Herbicide Dissipation Following Treatment of a Pond. Project Number:

842E4203E1, P/3657. Unpublished study prepared by FMC Corp. and NDR Res earch and Stone Environmental, Inc. 129 p.

SUBMITTED EFFECTS STUDIES CITED (See Appendix A for eco citations) 43189207 43189225 43189226 43189227 43189228 43189230 43829717 43849603 43849604 43849605 43849606 43892716 43939204 44165003 44165004 44165005 44165006 44165007 44165008 44165009 44165010 44165011 44165012 44165013 44165014 44165015 44165015 44165016 44165017 44165026 44176101 44176102 44176103 44176104 44176105 44176108 44409007 44419002 44419003 44419005 44419006 44419007 44419008 44419009 44424201 44633502 44963201 46037001

Mammalian Studies Cited:
44165026 Barton, S. (1994) F8426: Dose Range Finding Reproduction Study in Rats: Re vised Final Report: Lab

Project Number: A93

- 3759: 490835: 11056. Unpublished study prepared by Inveresk Research International. 162 p.

43189207 Freeman, C. (1994) Acute Oral Toxicity Study in Rats: F8426 Technical: Lab Project Number:

A92/3632. Unpublished study prepared by FMC Corp. 26 p.

### 48



## APPENDIX A : Carfentrazone

- ethyl Eco Effects Bibliography

71

- 1 Avian Single Dose Oral Toxicity

MRI D Citation Reference

43189225 2013852 Campbell, S.; Beavers, J. (1994) F8426 Technical: An Acute Oral Toxicity Study with the Northern Bobwhite: Lab Project Number: 104/175: A93/3769. Unpublished study prepared by Wildlife International Ltd. 18 p.



## 71

- 2 Avian Dietary Toxicity

MRID Citation Reference

43189226 2013850 Campbell, S.; Beavers, J. (1994) F8426 Technical: An Dietary LC50 Study with the Northern Bobwhite: Lab Project Number: 104/ 173: A93/3770. Unpublished study prepared by Wildlife International Ltd. 35 p.

43189227 2013851 Campbell, S.; Beavers, J. (1994) F8426 Technical: A Dietary LC50 Study with the Malla rd: Lab Project Number: A93/3768: 104/174. Unpublished study prepared by Wildlife International Ltd. 36 p.



## 71

- 4 Avian Reproduction

MRID Citation Reference

44419002 2013839 Pedersen, C. (1997) Avian Reproductive Toxicity Study with F8426 Technical in Bobwhite Quail: Lab Project Number: 112

- 013

- 07: A96

- 4402: 112S39A

- 2. Unpublished study prepared by Bio

- Life Associates, Ltd. 459 p.

44419003 2013835 Pedersen, C. (1997) Avian R eproductive Toxicity Study with F8426 Technical in Mallard Ducks: Lab Project Number: 112

- 014

- 08: A96

- 4403: 112S40. Unpublished study prepared by Bio

- Life Associates, Ltd. 539 p.



## 72

- 1 Acute Toxicity to Freshwater Fish

MRID Citation Reference

43189228 2082306 Sword, M.; Bucksath, J.; Bussard, J. (1994) Acute Flow

- Through Toxicity of F8426 Technical to Rainbow Trout (Oncorhynchus mykiss): Final Report: Lab Project Number: A93/3758: 40960. Unpublished study prepared by ABC Lab., Inc. 240 p.

43189229 2082307 Sword, M.; Bucksath, J.; Bussard, J.; et al. (1994) Acute Flow

- Through Toxicity of F8426 Technical to Bluegill (Lepomis macrochirus): Final Report: Lab Project Number: 40961: A93/3757. Unpublished study prepared by ABC Lab., Inc. 191 p.

### 49

44165009 2013828 Ward, T.; Magazu, J.; Boeri, R. (1995) Acute Toxicity of F8426

- Benzoic Acid to the Rainbow Trout, Oncorhynchus mykiss: (Final Report): Lab Project Number: A95

- 4210: 786

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 35 p.

44165013 2034176 Ward, T.; Kowalski, P.; Boeri, R. (1995) Acute Toxicity of F8426

- Propionic Acid to the Rainbow Trout, Oncorhynchus mykiss: (Final Report): Lab Project Number: A95

- 4214: 789

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 35 p.

44165015 2013830 Ward, T.; Kowalski, P.; Boeri, R. (1995) Acute Toxicity of F8426

- Chloropropionic Acid to the Rainbow Trout, Oncorhynchus mykiss: (Final Report): Lab Project Number: A95

- 4216: 782

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 35 p.

44176105 2013819

2013823 Cunningham, F. (1995) F8426

- Cinnamic Acid: Acute Toxicity to Rainbow

Trout, Oncorhynchus mykiss, Under Static Test Conditions: Lab Project Number: A95

- 4222: J9506003B: FMC/E103. Unpublished study prepared by Toxikon Enviro nmental Sciences. 45 p.



## 72

- 2 Acute Toxicity to Freshwater Invertebrates

MRID Citation Reference

43189230 2013849 Hicks, S.; Murrell, H.; Bucksath , J. (1994) Acute Flow

- Through Toxicity of F8426 Technical to Daphnia magna: Final Report: Lab Project Number: 40962: A93/3800. Unpublished study prepared by ABC Lab., Inc. 292 p.

44165007 2013821 Ward, T.; Magazu, J.; Boeri, R. (1995) Acute Toxicity of F8426

- Benzoic Acid to the Daphnid, Daphnia magna: (Final Report): Lab Project Number: A95

- 4208: 785

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 36 p.

44165011 2013822 Ward, T.; Kowalski, P.; Boeri, R. (1995) Acute Toxicity of F8426

- Propion ic Acid to the Daphnid, Daphnia magna: (Final Report): Lab Project Number: A95

- 4212: 788

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 37 p.

44165016 2013818 Ward, T.; Kowalski, P.; Boeri, R. (1995) Acute Toxicity of F8426

- Chloropropionic Ac id to the Daphnid, Daphnia magna: (Final Report): Lab Project Number: A95

- 4217: 781

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 35 p.

44176103 2013832 Cunningham, F. (1995) F8426

- Cinnamic Acid: Acute Toxicity to the Water Flea, Daphnia mag na, Under Static Test Conditions: Lab Project Number: A95

- 4220: J9506003A: FMC/E101. Unpublished study prepared by Toxikon Environmental Sciences. 44 p.

45168001 Mixture Samel, A. (2000) Carfentrazone Ethyl/Metsulfuron Methyl (DPX

- KW025) 50 WG (4:1): Static, Acute, 48

- Hour, Toxicity Test to Daphnia magna: Lab Project Number: 13204: 241: DUPONT

- 4145. Unpublished study prepared by E.I. du Pont de Nemours and Company. 38 p.

### 50



## 72

- 3 Acute Toxicity to Estuarine/Marine Organis ms

MRID Citation Reference

44165003 2013824 Dunham, M.; Cunningham, F. (1996) F8426 Technical: Acute Toxicity to the Mysid (Mysidopsis bahia) Under Flow

- Through Test Conditions: (Final Report): Lab Project Number: A96

- 4377: J9602001A: FMC/F8426/MYSIDOPSIS BAHIA/FT ACUTE. Unpublished study prepared by Toxikon Environmental Sciences. 45 p.

44165004 2013825 Cunningham, F. (1996) F8426 Technical: Acute Effects on New Shell Growth of the Eastern Oyster (Crassostrea virginica): (Final Report): Lab Project Number: A96

- 4378: J9602001C: FMC/F8426/OYSTER/GROWTH. Unpublished study prepared by Toxikon Environmental Sciences. 46 p.

44165005 201 3826 Dunham, M.; Cunningham, F. (1996) F8426 Technical: Acute Toxicity to the Tidewater Silverside (Menidia beryllina) Under Flow

- Through Conditions: (Final Report): Lab Project Number: A96

- 4376: J9602001B: FMC/F8426/MENIDIA BERYLLINA/FT ACUTE. Unpublished study prepared by Toxikon Environmental Sciences. 45 p.



## 72

- 4 or 850

- 1400 Fish Early Life Stage/Aquatic Invertebrate Life Cycle Study

MRID Citation Reference

44419006 2013838

2013840 Knacker, T.; Schallnas, H.; Weidenauer , M. (1992) A Study on the Chronic

Toxicity of F8426 Technical to Daphnia magna: Lab Project Number: A96

- 4547: 91186

- FMC: A

- 17

- 95

- 35. Unpublished study prepared by ECT Oekotoxikologie GmbH and Battelle. 148 p.

44424201 2013834

2034173 Liu, H.; Kranzfelder, J.; Groetsch, K. (1997) Carfentrazone

- ethyl (F8426)

Technical: Toxicity to Embryos and Larvae of the Rainbow Trout, Oncorhynchus mykiss, Under Flow

- Through Test Conditions: Lab Project Number: A96

- 4528: J9609004A: FMC/F8426/RT ELS. Unpublished study prepared by Toxikon Environmental Sciences. 121 p.

44963201 2013845 Ellenberg, W.; Rielly, P.; Glover, S. (1999) Carfentrazone

- ethyl (F8426) Technical: Toxicity to Embryos and Larvae of the Rainbow Trout, Oncorhynchus mykiss, Under Flow

- Through Co nditions: Lab Project Number: 99J0001: A99

- 4961: FMC/F8426/RT ELS. Unpublished study prepared by Toxikon Corporation. 148 p.

46037001 2016951 Ross, T.; Kendall, T.; Krueger, H. (2003) F8426: An Early Life

- Stage Toxicity Test with the Rainbow Trout (Oncor hynchus mykiss) Under Ultraviolet Light Conditions: Final Report. Project Number: 104A/107, A2001/5397. Unpublished study prepared by Wildlife International, Ltd. 72 p.

### 51



## 122

- 2 Aquatic plant growth

MRID Citation Reference

44419004 2013836 Ward, T.; Kowalski, P.; Boeri, R. (1997) Growth and Reproduction Toxicity Test with F8426 Cinnamic Acid and the Freshwater Alga, Selenastrum capricornutum: Lab Project Number: A96

- 4468: 1068

- FM. Unpublished study prepared by T.R. Wilbury Labs., Inc. 41 p.



## 123

- 1 Seed germination/seedling emergence and vegitative vigor

MRID Citation Reference

43829716 2034151 Feutz , E. (1994) Evaluating the Effects of F8426 on the Germination, Emergence, and Vegetative Vigor of Non

- Target Terrestrial Plants: Final Report: Lab Project Number: 41031: PC

- 0209: 842E7393E1. Unpublished study prepared by ABC Labs, Inc. 365 p.

43939204 2013858 Feutz, E. (1996) Evaluating the Effects of F8426 on the Germination, Emergence, and Vegetative Vigor of Non

- Target Terrestrial Plants: Supplement to Final Report: Lab Project Number: 41031: 842E7393E1: PC

- 0209. Unpublished study prepared by ABC Lab s, Inc. 253 p.



## 123

- 2 Aquatic plant growth

MRID Citation Reference

43829717 2013856 Hicks, S.; Bussard, J. (1994) Acute Toxicity of F8426 Technical to Selenastrum capricornutum Printz : Final Report: Lab Project Number: 40964: A93

- 3801. Unpublished study prepared by ABC Labs, Inc. 397 p.

43849603 2013857 Forbis, A.; Ziegler, T.; Veltri , J. (1995) Acute Toxicity of F8426 Technical to Lemna gibba G3: Final Report: Lab Project Number: 42391: A94

- 4112: ABC 42391. Unpublished study prepared by ABC Labs, Inc. 85 p.

43849604 2013855 Forbis, A.; Ziegler, T.; Bucksath, J. (1995) Acute Toxicity of F8426 Technical to Skeletonema costatum: Final Report: Lab Project Number: 42388: A94

- 4113: ABC 42388. Unpublished study prepared by ABC Labs, Inc. 82 p.

43849605 2013853 Forbis, A.; Ziegler, T.; Bucksath, J. (1995) Acute Toxicity of F8426 Technical to Navicula pelliculosa Final Report: Lab Project Number: 42389: A94

- 4114: ABC 42389. Unpublished study prepared by ABC Labs, Inc. 82 p.

43849606 2013854 Forbis, A.; Ziegler, T.; Bucksath, J. (1995) Acute Toxicity of F8426 Technical to Anabaena flos

- aqua e Final Report: Lab Project Number: 42390: A94

- 4115: ABC 42390. Unpublished study prepared by ABC Labs, Inc. 81 p.

44165006 2013820 Ward, T.; Magazu, J.; Boeri, R. (1995) Acute Toxicity of F8426

- Benzoic Acid to the Freshwater Alga, Selenastrum capricornu tum: (Final Report): Lab Project Number: A95

- 4140: 708

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 38 p.

### 52

44165010 2013829 Ward, T.; Kowalski, P.; Boeri , R. (1995) Acute Toxicity of F8426

- Propionic Acid to the Freshwater Alga, Selenastrum capricornutum: (Final Report): Lab Project Number: A95

- 4211: 790

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 38 p.

44165014 2014020 Ward, T.; Kowalski, P.; Boeri, R. (1995) Acute Toxicity of F8426

- Chloropropionic Acid to the Freshwater Alga, Selenastrum capricornutum: (Final Report): Lab Project Number: A95

- 4215: 783

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 38 p.

44176102 2013817 Cunningham, F. (1995) F8426

- Cinnamic Acid: Toxicity to the Freshwater Green Alga, Selenastrum capricornutum, Under Static Test Conditions: Lab Project Number: A95

- 4219: J9506003C: FMC/E106.9. Unpublished study prepared by Toxikon Environmental Sciences. 52 p.

44419005 2013837 Ward, T.; Kowalski, P.; Boeri, R. (1997) Growth and Reproduction Toxicity Test with F8426 Technical and the Freshwater Alga, Selenastrum capricornutum: Lab Project Number: A96

- 4496: 1069

- FM. Unpublished study prepared by T.R. Wilbury Labs., Inc. 41 p.

45626901 Hahne, R.; Koch, D.; Jackson

- Gheissani, A. (2002) Toxicity of a Mixture of Parent (F8426 Technical) and Two Metabolites to Duckweed, Lemna gibba G3, Determined Under Static Test Conditions: Lab Project Number: 47254: A2002

- 54 98. Unpublished study prepared by ABC Laboratories, Inc. 59 p.



## 141

- 1 Honey bee acute contact

MRID Citation Reference

44176108 2013827 Beech, P. (1995) Carfentrazone (F8426): A Determination of Topical and Oral LD50s for the Honey Bee, Apis mellifera: Lab Project Number: FMC

- 95

- 1: 842AF95304. Unpublished study prepared by Agrochemical Evaluation Unit. 21 p.

44633502 2013843 Liu, H.; Kranzfelder , J. (1998) F8426: Honey Bee Acute Contact LD50: Lab Project Number: J9710009: A97

- 4748: F605. Unpublished study prepared by Toxikon Environmental Sciences. 30 p.



## Non Guideline Selections

44165002 Analytical

Method Validation Wenger, K. (1996) F8426 Technical: Analytical Method Validation in Filtered

and Unfiltered Saltwater: Lab Project Number: V96

- 0046: J9602001D: FMC/SWMV/F8426. Unpublished study prepared by Toxikon Environmental Sciences. 32 p.

44165008 2036868 Ward, T.; Magazu, J.; Boeri, R. (1995) Acute Toxicity of F8426

- Benzoic Acid to the Earthworm, Eisenia foetida: (Final Report): Lab Project Number: A95

- 4209: 784

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 32 p.

44165012 2036870 Ward, T.; Kowalski, P .; Boeri, R. (1995) Acute Toxicity of F8426

- Propionic Acid to the Earthworm, Eisenia foetida: (Final Report): Lab Project Number: A95

- 4213: 787

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 31 p.

### 53

44165017 2036871 Ward, T.; Kowalski, P.; Boe ri, R. (1995) Acute Toxicity of F8426

- Chloropropionic Acid to the Earthworm, Eisenia foetida: (Final Report): Lab Project Number: A95

- 4218: 780

- FM. Unpublished study prepared by T. R. Wilbury Labs, Inc. 31 p.

44176101 2036867 Sword, M.; Bucksath, J.; Bu ssard, J. (1994) 14

- Day Toxicity of F8426 Technical to the Earthworm, Eisenia foetida: Final Report: Lab Project Number: 40963: A93

- 3802: 040963. Unpublished study prepared by ABC Labs., Inc. 236 p.

44176104 2036869 Aufderheide, J.; Kranzfelder , J. (1995) F8426

- Cinnamic Acid: Acute Toxicity to the Earthworm, Eisenia foetida (Soil Test): Lab Project Number: A95

- 4221: J9506003D: J9506003D/FMC A95

- 42. Unpublished study prepared by Toxikon Environmental Sciences. 37 p.

44419007 Ward, T.; Magazu, J.; Boeri, R. (1997) Acute Toxicity of F8426

-- Chloropropionic Acid to the Earthworm, Eisenia foetida: Report Addendum: Lab Project Number: A95

- 4218

- 01: 780

- FM. Unpublished study prepared by T.R. Wilbury Labs., Inc. 15 p.

44419008 Ward, T.; Magazu, J.; B oeri, R. (1997) Acute Toxicity of F8426

-- Propionic Acid to the Earthworm, Eisenia foetida: Report Addendum: Lab Project Number: A95

- 4213

- 01: 787

- FM. Unpublished study prepared by T.R. Wilbury Labs., Inc. 15 p.

44419009 Ward, T.; Magazu, J.; Boeri, R. (1 997) Acute Toxicity of F8426

-- Benzoic Acid to the Earthworm, Eisenia foetida: Report Addendum: Lab Project Number: A95

- 4209

- 01: 784

- FM. Unpublished study prepared by T.R. Wilbury Labs., Inc. 15 p.

45902901 Herrick, R. (2003) Efficacy of F

- 8426 Aquatic H erbicide for Aquatic Weed Control: Lab Project Number: PDM

- 037

- 03. Unpublished study prepared by FMC Corporation. 33 p. {OPPTS 810.1000}

45902903 Jackson

- Gheissari , A. (2003) Ecological Exposure and Risk Assessment for Aquatic Applications of Carfentrazone

- Ethyl: Lab Project Number: A2003

- 5602. Unpublished study prepared by FMC Corporation. 37 p.

45902904 Keifer, D. (2003) Application of F8426 and F8426

- Chloropro pionic Acid to Plant Foliage in Irrigation Water: Lab Project Number: P

- 3594: G030.202. Unpublished study prepared by FMC Corporation

46305703 Nissin

- Meyer, S.; McCoy, E.; Holihan, J.; et. al. (2003) Ecological Exposure and Risk Assessment for the Use of Carfentrazone

- Ethyl (F8426) Herbicide for Site Preparation. Project Number: A2003/5667. Unpublished study prepared by FMC Corp. Agricultural Products Group. 30 p.

46305704 Nissen

- Meyer, S. (2004) Ecological Exposure and Risk Assessment for Non

Target Te rrestrial, Semi

- Aquatic, and Aquatic Plants from the Use of Carfentrazone ROW Herbicide. Project Number: P/3713. Unpublished study prepared by FMC Corp. Agricultural Products Group. 30 p.

### 54



## APPENDIX B : Environmental Degradates of Carfentrazone

- et hyl

.

TABLE B 1. Carfentrazone

- ethyl and Its Major Environmental Degradates.
Code Name/ S ynonym Chemical N ame Chemical S tructure Study Type Maximum %AR (day) Final %AR

(study length)

PARENT COMPOUND 

### Carfentrazone

ethyl
F8426
FMC 116426 Ethyl α,2

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoate

CAS No.: 128639

- 02

- 1

Formula: C 15 H 14 Cl 2 F 3 N 3 O 3 MW: 412.20 g/mol Aerobic soil MRID 44165034 Aqueous photolysis MRID 44934201 Hydrolysis MRID 4 3189231 Aerobic aquatic MRID 44419016
Field studies MRID 44165039

MRID 44 419017
MRID 44 419019 MRID 46253901

TRANSFORMATION PRODUCTS 

### Carfentrazone
F8426

- chloro

propionic acid
F8426

- Cl

- PAc
FMC 124161 α,2

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoic acid

CAS No.: 128621

- 72

- 7

Formula: C 13 H 10 Cl 2 F 3 N 3 O 3 MW: 384.14 g/mol Aerobic soil 90 % ( 1.3 d) n.d. A ( 365 d) Aqueous photolysis not identified Hydrolysis

– pH 5

– pH 7

– pH 9 9.5% (30 d)

90.0% (30 d) 99.7% (14 d) 9.5% ( 30 d)

90.0% (30 d) 97.5% (30 d) Aerobic aquatic 80% (1 d, 7 d) 59% (30 d)
Field studies

Water:

Sediment:
Water: Sediment: 49 μg/L (1 d) n.d. A ( 356 d)

33 μg/L (0 d) n.d. A (178 d) 81 μg/L (0 d) 34 μg/kg (0 d) n.d. A (80 d)

1

- 5 μg/kg (365 d) 6.8 μg/L (1 d) 1.9 μg/kg (30 d) n.d. A ( 30 d)

1.9 μg/kg (30 d) 

### F8426

- cinnamic acid
F8426

- CAc
FMC 125151 2

- chloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropenoic acid

Formula: C 13 H 9 ClF 3 N 3 O 3 MW: 347.68 g/mol Aerobic soil 51% (33 d) 31% (365 d) Aqueous photolysis n ot identified Hydrolysis n ot identified Aerobic aquatic 11% (21 d) 8.8% (30 d)
Field studies

Water:

Sediment: 5.0 μg/L (7 d) n.d. A ( 356 d)

6.1 μg/L (14 d) n.d. A ( 652 d)
5 μg/L (21 d) 10 μg/kg (1 d) n.d. A (80 d)

1

- 5 μg/kg (365 d) not analyzed

### 55

Code Name/ S ynonym Chemical N ame Chemical S tructure Study Type Maximum %AR (day) Final %AR

(study length)
F8426

- propionic acid
F8426

- PAc
FMC 125165 2

- chloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoic acid

Formula: C 13 H 11 ClF 3 N 3 O 3 MW: 349.70 g/mol Aerobic soil 23% (270 d) 20% (365 d) Aqueous photolysis n ot identified Hydrolysis n ot identified Aerobic aquatic 16% (30 d) 16% (30 d)
Field studies

Water:

Sediment: 6.2 μg/L (14 d) n.d. A ( 356 d)

3.7 μg/L (14 d) n.d. A ( 178 d)
9 μg/L (7 d) 11 μg/kg (7 d) n.d. A (80 d)

1

- 5 μg/kg (365 d) not analyzed 

### F8426

- benzoic acid
F8426

- BAc
FMC 97083 2

- chloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzoic acid

Formula: C 11 H 7 ClF 3 N 3 O 3 MW: 321.64 g/mol Aerobic soil 22% (365 d) 22% (365 d) Aqueous photolysis n ot identified Hydrolysis n ot identified Aerobic aquatic 3.6% (30 d) 3.6% (30 d)
Field studies

Water:

Sediment: 14 μg/L (14 d) n.d. A ( 356 d)

5.4 μg/L (21 d) n.d. A ( 178 d)
n.d. A
1

- 5 μg/kg (0 d) n.d. A (80 d)

n.d. A (365 d) not analyzed 

### α,2 ,4

- trihydroxy

F8426 Ethyl α,2,4

- trihydroxy

- 5

- [4

-

(difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- benzenepropanoate

Formula: C 15 H 17 F 2 N 3 O 6 MW: 373.32 g/mol Aerobic soil n ot identified Aqueous photolysis 18% (15 d) 18% (15 d) Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies not analyzed



### α - hydroxy

- F8426 Ethyl α

- hydroxy

- 2

- dichloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoate

Formula: C 15 H 15 ClF 3 N 3 O 4 MW: 393.75 g/mol Aerobic soil n ot identified Aqueous photolysis 12 % (8 d) 2.8% (15 d) Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies not analyzed

### 56

Code Name/ S ynonym Chemical N ame Chemical S tructure Study Type Maximum %AR (day) Final %AR

(study length)

α - hydroxymethyl

2,4

- dihydroxy

F8426 Ethyl α

- hydroxymethyl

- 2,4

-

dihydroxy

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- methyl

- 5

- oxo

- 1H

1,2,4

- triazol

- 1

- yl]

- benzeneethanoate

Formula: C 15 H 17 F 2 N 3 O 6 MW: 373.32 g/mol Aerobic soil n ot identified Aqueous photolysis 15 % (15 d) 15% (15 d) Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies not analyzed



### 3

- hydroxymethyl

F8426

- chloropropionic acid
3

- hydroxymethyl

carfentrazone α,2

- dichloro

- 5

- [4

-

(difluoromethyl)

- 4,5

- dihydro

- 3

- hydroxymethyl

- 5

- oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropanoic acid

Formula: C 13 H 10 Cl 2 F 3 N 3 O 4 MW: 400.14 g/mol Aerobic soil 9.1% (100 d) 7.9% (365 d) Aqueous photolysis n ot identified Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies not analyzed



### 3

- hydroxymethyl

F8426

- cinnamic acid 2

- chloro

- 5

- [4

- (difluoromethyl)

-

4,5

- dihydro

- 3

- hydroxymethyl

- 5

-
oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzenepropenoic acid

Formula: C 13 H 9 ClF 3 N 3 O 4 MW: 363.68 g/mol Aerobic soil 5.9% (365 d) 5.9% (365 d) Aqueous photolysis n ot identified Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies not analyzed



### 3

- hydroxymethyl

F8426

- benzoic acid
FMC 125171 2

- chloro

- 5

- [4

- (difluoromethyl)

- 4,5

- dihydro

- 3

- hydroxymethyl

- 5

-
oxo

- 1H

- 1,2,4

- triazol

- 1

- yl]

- 4

- fluorobenzoic acid

Formula: C 11 H 7 ClF 3 N 3 O 4 MW: 337 .64 g/mol Aerobic soil 24% (365 d) 24% (365 d) Aqueous photolysis not identified Hydrolysis n ot identified Aerobic aquatic n ot identified
Field studies

Water:

Sediment: not analyzed

1.6 μg/L (44 d) n.d. A ( 178 d)
1

- 5 μg/L (3 d) 1

- 5 μg/kg (14 d) n.d. A (80 d)

n.d. A (365 d) not analyzed 

### Unknown 7 ( unknown ) ( unknown ) Aerobic soil 18 % (365 d) 18% (365 d)

### 57

Code Name/ S ynonym Chemical N ame Chemical S tructure Study Type Maximum %AR (day) Final %AR

(study length)
Carbon dioxide Carbon dioxide

Formula: CO 2 MW: 44.1 g/mol Aerobic soil not analyzed Aqueous photolysis 4.6% (15 d) 4.6% (15 d) Hydrolysis not analyzed Aerobic aquatic not analyzed 

### Volatile compounds (not applicable)

(not applicable) Aerobic soil 2.5% (365 d) 2.5% (365 d) Aqueous photolysis n.d. A (15 d) n.d. A (15 d) Hydrolysis not analyzed Aerobic aquatic 0.4% (30 d) 0.4% (30 d) 

### Unextracted residues (not applicable) (not applicable) Aerobic soil 40.3% (365 d) 40.3% (365 d) Aerobic aquatic 6.1% (21 d) 4.2% (30 d)

A “n.d.” means “not detected. ”

## APPENDIX C : Data Call

- In Tables

.

The followi ng proposed Data Call

- in tables include rationales for requiring the data requested in this problem formulation, explanations of the utility of the data, and explanations for how the data might impact risk assessment, following the format provided by the Pesticide Re

- evaluation Division.

Guideline Number: 835.2240 Study Title: Photodegradation in Water (Degradate) Rationale for Requiring the Data The Agency has a limited understanding of how carfentrazone acid (degradate of carfentrazone

- ethyl) behaves in the environment once the parent compound is applied. Depending on how quickly, to what extent, and to which transformation products the compound degrades, carfentrazone acid may or may not pose potential exposure concern in water bodies.

Submitted data regarding photodegradation of carfentrazone acid in water (MRID 44165032) are not acceptable for risk assessment. T he sterility of the samples wa s not determined during the study and material balances were poor in some samples, showing a pattern of decline over time

. In order to better understand the photodegradation of carfentrazone acid residues in water, the Agency is requiring an aqueous photo lysis study of carfentrazone (rather than carfentrazone

- ethyl) tha t fulfills the data requirement

. Practical Utility of the Data How will the data be used? Submission of an acceptable aqueous photolysis study will facilitate a better understanding of carfentrazone under irradiated, aqueous conditions. If data indicate that photolysis of dissolved residues of concern is rapid, then the Agency could potentially determine that carfentrazone residues of concern do not persist in water bodies in which phot olysis occurs ( i.e. , clear, shallow water bodies). If data indicate that photolysis of dissolved residues of concern is not appreciable in water, then the Agency would rely on hydrolysis and aqueous biometabolism data to determine whether carfentrazone re sidues persist in water.

How could the data change the Agency’s decision, or impact the Agency’s future decision

making? In the absence of adequate aqueous photolysis data, carfentrazone residues in water will be assumed stable to photodegradation. If the required data indicate that carfentrazone residues in water are readily photolyzed, then risk assessment conclusions and associated labeled use precautions and/or restrictions could change.

Guideline Number: 835.4400 Study Title: Anaerobic Aquatic Metabolism Rationale for Requiring the Data The Agency has a limited understanding of how carfentrazone

- ethyl behaves in anaerobic aquatic environments once applied. Depending on how quickly, to what extent, and to which transformation products the compound degrades, carfentrazone

- ethyl may or may not pose potential exposure concern in water. Because carfentrazone

- ethyl degradation in anaerobic surface water systems is not well understood, the Agency is requiring data.

### 59 Practical Utility of the Data How will the data be used? Anaerobic aquatic metabolism data will facilitate a better understanding of the fate of carfentrazone

ethyl residues in water. If data indicate that degradation in anaerobic conditions occurs rapidly in acidic, surficial aquatic systems and produces nonto xic transformation products, then the Agency could potentially determine that carfentrazone

- ethyl residues of concern do not persist in these systems. If data indicate that degradation is not appreciable in acidic, surficial aquatic systems or that the
tr ansformation products are of similar or higher toxicity than the parent compound, then the Agency could conclude that carfentrazone

- ethyl residues of concern persist in acidic, surficial aquatic systems under anaerobic conditions.

How could the data chang e the Agency’s decision or impact the Agency’s future decision

- making? In the absence of the requested data, carfentrazone

- ethyl will be assumed stable to biodegradation in anaerobic, surficial aquatic environments. If the required data indicate that ca rfentrazone

- ethyl in anaerobic surficial aquatic environments is rapidly biodegraded to nontoxic degradation products, including in acidic conditions, then risk assessment conclusions and associated labeled use precautions and/or restrictions could be made less restrictive.

Guideline Number: 835.6100 (Independent Laboratory Validation Only) Study Title: In dependent Laboratory Validation of Analytical Method for Residues in Soil Rationale for Requiring the Data Independently validated analytical methods for residues in soil, water, sediment, and plant material (environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in submitted environmental fate and ecological effects studies. Submitted analytical methods a re also used by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent laboratory validations for submitted a nalytical methods are necessary to confirm that the methods are functional and to confirm the levels of detection and quantitation reported in registrant

prepared validations.

An analytical method ( a.k.a. environmental chemistry method) for carfentrazone

- ethyl residues in soil (parent plus degradates carfentrazone, F8426

- cinnamic acid, F8426

- propionic acid, and F8426

- benzoic acid), MRID 44161540

, was subm itted by the registrant in support of the terrestrial field dissipation study, MRID 44161539 . However, an independent validation o f this method was not submitted

. Therefore, an independent laboratory validation of the submitted analytical method for carfentrazone

ethyl residues in soil (MRID 44161540 ) is required in order to evaluate MRID 44161539

. Practical Utility of the Data How will the data be used? In the absence of independent validation, the submitted environmental chemistry method MRID 44161540 and the field study it supports, MRID 44161539, are not reviewable. An i ndependently validated environmental chemistry method will be used to evaluate the s ubmitted data and will be made available for enforcement and monitoring purposes at the federal, state, and local levels.

How could the data change the Agency’s decision, or impact the Agency’s future decision

making? Risk assessment conclusions could be altered if they are not supported by field study data or environmental monitoring detections that are based on independen tly validated environmental chemistry methods.

### 60

Guideline Number: 835.6200 (Frozen Storage Stability Study Only) Study Title: Storage Stability of Residues in Frozen Water and Sediment Rationale for Requiring the Data The Agency has a limited understanding of how carfentrazone

- ethyl behaves when app lied to rice paddies. Depending on how quickly and to what extent the compound and its main degradates dissipate from rice paddies

, carfentrazone

- ethyl residues may or may n ot pose potential exposure concern in and down stream from rice paddies . Because carfentrazone

- ethyl dissipation in rice paddies is no t well understood, the Agency requ ired an aquatic field dissipation study of carfentrazone

- ethyl applied to rice paddies i n California and Louisiana

. This study was submitted under MRID 44654701.

Storage stability data for carfentrazone

- ethyl and analyzed degradates (carfentrazone , F8426

- propionic acid, F8426

- cinnamic acid, F8426

- benzoic acid, and 3

- hydroxymethyl

- F8426

- benzoic acid) in water and sediment samples in frozen storage were not subm itted by the registrant in support of MRID 44 654701

. The field study data are not reviewable without storage stability data to indicate whether and how much

r esidues degrade during handling, storage, and processing of samples. Therefore, these data are required in order to evaluate MRID 4 4654701

. Practical Utility of the Data How will the data be used? In the absence of frozen storage stability data , the submitted aquatic field dissipation study, MRID 44654701, is not reviewable. Frozen storage stability data will be used to evaluate the submitted data

, by indicating whether and how much residues degrade during handling, storage, and processing of

s amples.

How could the data change the Agency’s decision, or impact the Agency’s future decision

making? Risk assessment conclusions could be altered if they are not supported by field study data or if laboratory study data are not consistent with field study data that are supported with acceptable storage stability data.

Guideline Number: 850. 10 25 Study Title: Oyster Acute Toxicity Test (Shell Deposition) with carfentrazone acid Rationale for Requiring the Data Acute toxicity data are required per 40 CFR Part 158.630 for aquatic invertebrates for all terrestrial and aquatic uses . Since carfentrazone

- ethyl converts rapidly, 2.3

- 2.7 h, into carfentrazone acid, which has an aerobic aqu a tic half

- life of 39

- 72 d, the data are needed with carfentrazone acid

.

Practical Utility of the Data How will the data be used? Acute data on the acid degradate would allow the Agency to better assess and characterize toxicity ; acute toxicity of carfentrazone

- ethyl may be different from carfentrazone acid. The effects data would be used to determine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on fish or by indirect e ffects by reducing their food sources. By refining the assessment, the Agency would be able to determine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity concerns with carfentrazone

- ethyl or its maj or degradate, carfentrazone acid

.
How could the data impact the Agency’s future decision

- making? If future endangered species risk assessments are performed without these data, the Agency would have to assume that carfentrazone

- ethyl "may affect" endangered saltwater mollusks directly (and endangered

### 61

species from other taxa indirectly), and use of car fentrazone

- ethyl might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result i n use restrictions for carfentrazone

- ethyl which are unnecessarily severe.

Guideline Number: 850. 1075 Study Title: Fish Acute Toxicity Test ( Saltwater ) with carfentrazone acid Rationale for Requiring the Data Acute toxicity data are required per 40 CFR Part 158.630 for fish for all terrestrial and aquatic uses

. Since carfentrazone

- ethyl converts rapidly, 2.3

- 2.7 h, into carfentrazone acid, which has an aerobic aquatic half

- life of 39

- 72 d, the data are needed with carfentrazone acid

. The specie s used should be the same as the saltwater fish ELS test with the acid degradate. Practical Utility of the Data How will the data be used? Acute data on the acid degradate would allow the Agency to better assess and characterize toxicity; acute toxicity of carfentrazone

- ethyl may be different from carfentrazone acid. The effects data would be used to determine the likelihood that the acute risks can potentially impact aquatic communities, either by direct effects on fish or by indirect effects by reducing their food sources. By refining the assessment, the Agency would be able to determine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity conce rns with carfentrazone

- ethyl or its major degradate, carfentrazone acid

.
How could the data impact the Agency’s future decision

- making? If future endangered species risk assessments are performed without these data, the Agency would have to assume that carfentrazone

- ethyl "may affect" endangered saltwater mollusks directly (and endangered species from other taxa indirectly), and use of car fentrazone

- ethyl might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result i n use restrictions for carfentrazone

- ethyl which are unnecessarily severe.

Guideline Number: 850. 1400 Study Title: Fish Early Life

- Stage Test ( Saltwater ) with carfentrazone acid Rationale for Requiring the Data Since carfentrazone

- ethyl may be applied directly to water, this data is required per 40 CFR Part 158.630 . Since the aerobic aquatic half

- life is 2.3

- 2.7 h for parent, but 39

- 72 d for carfentrazone acid, the data is being requested using carfentrazone acid , which is the dominant form expected in chronic aquatic exposure. The species used should be the same as the saltwater fish acute test with the acid degradate. Practical Utility of the Data How will the data be used? The fish full life

- cycle study would allow the Agency to analyze chronic effects, including effects on reproductive success and growth, to fish and aquatic

- phase amphibians. The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by di rect effects on fish or by indirect effects by reducing their food sources. By refining the assessment, the Agency would be able to determine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity concern s with carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making?

### 62

If future endangered species risk assessments are performed without these data, the Agency would have to assume that carfentrazone

- ethyl "may affect" endangered fis h and aquatic

- phase amphibians directly (and endangered species from other taxa indirectly), and use of carfentrazone

- ethyl might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility t he Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for carfentrazone

- ethyl which are unnecessarily severe.

Guideline Number: 850.1500 Study Title: Fish Full Life

- cycle Test (Freshwater) with carfentrazone acid Rationale for Requiring the Data Since carfentrazone

- ethyl may be applied directly to water, and the expected EEC is > 0.1 of the early life stage NOAEC for rainbow trout (i.e ., <16.4 μg a.i./L, based on LDPH toxicity, MRID 44963201), this study is required per 40 CFR Part 158.630. Available environmental fate data indicate that carfentrazone

- ethyl is not persistent in aquatic environments (aerobic aquatic half

- life is 2.3

- 2.7 h); however, chronic exposures are of potential concern for its major degradate, carfentrazone acid, which has aerobic aquatic half

- lives ranging 39 to 72 d. At this time, chronic toxicity data are not available for fish exposed to carfentrazone acid. The refore, the data is being requested using carfentrazone acid, which is the dominant form expected in chronic aquatic exposure. Rainbow trout should be used since acceptable acute toxicity data with the acid degradate are available for this species

. Practical Utility of the Data How will the data be used? The fish full life

- cycle study would allow the Agency to analyze chronic effects, including effects on reproductive success and growth, to fish and aquatic

- phase amphibians. The effects data woul d be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by direct effects on fish or by indirect effects by reducing their food sources. By refining the assessment, the Agency would be able to determ ine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity concerns with carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? If future endangered species risk assessments a re performed without these data, the Agency would have to assume that carfentrazone

- ethyl "may affect" endangered fish and aquatic

- phase amphibians directly (and endangered species from other taxa indirectly), and use of carfentrazone

- ethyl might need to b e restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for carfentra zone

- ethyl which are unnecessarily severe.

Guideline Number: 850.1300 Study Title: Daphnid Chronic Toxicity Test with carfentrazone acid. Rationale for Requiring the Data Carfentrazone

- ethyl is moderately toxic to aquatic invertebrates on an acute basis. It may be applied directly to water, and t he persistence of carfentrazone

- ethyl in water does not preclude the potential for chronic exposure to be sufficient to elicit to xic responses. This requirement is based on carfentrazone

ethyl use in a variety of products applied directly to water and used in agriculture. Since carfentrazone

ethyl may be applied directly to freshwater, a life

- cycle study is required using a fresh water daphnid

. Since the aerobic aquatic half

- life is 2.3

- 2.7 h for parent, but 39

- 72 d for carfentrazone acid, the data are being requested on the acid form, which is the dominant form expected in chronic aquatic exposure. Daphnia magna should be used since acceptable acute toxicity data with the degradate are available.

### 63 Practical Utility of the Data How will the data be used? The full life

- cycle study would allow the Agency to further analyze potential chronic effects. The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by direct effects on aquatic invertebrates or by indirect effects by reducing their food sources. By refining the assessment, the Agen cy would be able to determine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity concerns with carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? If future endangered species risk assessments are performed without these data, the Agency would have to assume that carfentrazone

ethyl "may affect" endangered aquatic invertebrates directly (and endangered species from other taxa indirectly), and use of carfentrazone

- ethyl m ight need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for carfentrazone

- ethyl which are unnecessarily severe.

Guideline Number: 850.13 5 0 Study Title: Mysid Chronic Toxicity Test with carfentrazone acid. Rationale for Requiring the Data Carfentrazone

- ethyl is moderately toxic to aquatic invertebrates on an acute basis. It may be applied directly to water, and t he persistence of carfentrazone

- ethyl in water does not preclude the potential for chronic exposure to be sufficient to elicit to xic responses. This requirement is based on carfentrazone

ethyl use in a variety of products applied directly to water and used in agriculture. Since carfentrazone

ethyl may be applied directly to saltwater , a life

- cycle study is required using a saltwa ter mysid

. Since the aerobic aquatic half

- life is 2.3

- 2.7 h for parent, but 39

- 72 d for carfentrazone acid, the data are being requested on the acid form, which is the dominant form expected in chronic aquatic exposure. Mysidopsis bahia should be used si nce acceptable acute data is available for this species with the acid degradate. Practical Utility of the Data How will the data be used? The full life

- cycle study would allow the Agency to further analyze potential chronic effects. The effects data would be used to determine the likelihood that the chronic risks can potentially impact aquatic communities, either by direct effects on aquatic invertebrates or by indirect effects by reducing their food sources. By refining the assessment, the Agency wo uld be able to determine whether the mitigation imposed as part of the registration review process was appropriate due to toxicity concerns with carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? If future endangered speci es risk assessments are performed without these data, the Agency would have to assume that carfentrazone

ethyl "may affect" endangered aquatic invertebrates directly (and endangered species from other taxa indirectly), and use of carfentrazone

- ethyl might need to be restricted in areas where endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act and could result in use restrictions for carfentrazone

- ethyl which are unnecessarily severe.

### 64

Guideline Numbers: 850. 1735 Study Title: W hole sediment Acute Toxicity Invertebrates, Freshwater with TGAI using Hyalella Rationale for Requiring the Data Available information indicates that benthic organisms may be exposed via run

- off or spray drift applications used in agricultural, forest, and residential settings, or by direct application to water. The Kow and dissipation half

- lives meet the criteria for requiring an acute sediment organism toxicity study. Sediment toxicity tests are required to satisfy the Agency‟s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007).

Acute tests using freshwater species, Hyalella azteca and Chironomus tentans

, are requested. Although both Hyalella and Chironomus are freshwater species, they differ substantially in their ecological niche ( i.e. , epibenthic vs. infaunal), physiology, and potential sensitivities to pesticide exposure. Pra ctical Utility of the Data How will the data be used? Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms associated with uses of carfentrazone

- ethyl. The data will reduce uncertainties associated with the current risk assessment for benthic species and will improve our understanding of the potential effects of carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? Acceptable data for benthic organisms will reduce the uncertain ty from previous assessments. If the data indicate that registered carfentrazone

- ethyl usage may pose a risk of adverse effects to non

- target benthic organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this ri sk. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for carfentrazone

- ethyl which may otherwise be avoided, or which are unne cessarily severe.

Guideline Numbers: 850. 1735 Study Title: W hole sediment Acute Toxicity Invertebrates, Freshwater with TGAI using Chironomus Rationale for Requiring the Data Available information indicates that benthic organisms may be exposed via run

- off or spray drift applications used in agricultural, forest, and residential settings, or by direct application to water. The Kow and dissipation half

- lives meet the criteria for requiring an acute sediment organism toxicity study. Sediment toxicity tests are required to satisfy the Agency‟s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007).

Acute tests using freshwater species, Hyalella azteca and Chironomus tentans

, are requested. Although both Hyalella and Chironomus are freshwater species, they differ substantially in their ecological niche ( i.e. , epibenthic vs. infaunal), physiology, and potential sensitivities to pesticide exposure. Pr actical Utility of the Data How will the data be used? Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms associated with uses of carfentrazone

- ethyl. The data will reduce uncertainties associated with the current risk assessment for benthic species and will improve our understanding of the potential effects of carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? Acceptable data for benthic organisms will reduce the uncertain ty from previous assessments. If the

### 65

data indicate that registered carfentrazone

- ethyl usage may pose a risk of adverse effects to non

- target benthic organisms above the Agency Level of Concern, the Agency may explore decision options to mitigate this ri sk. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for carfentrazone

- ethyl which may otherwise be avoided, or which are unne cessarily severe.

Guideline Numbers: 850. 1740 Study Title: W hole sediment Acute Toxicity Invertebrates, Marine Rationale for Requiring the Data Available information indicates that benthic organisms may be exposed via run

- off or spray drift applications used in agricultural, forest, and residential settings, or by direct application to water. The Kow and dissipation half

- lives meets the criteria for requiring an acute sediment organism toxicity study. Sediment toxicity tests are required to satisfy the Agency‟s updated data requirements for outdoor uses in 40 CFR Part 158 (October 26, 2007).

Carfentrazone

- ethyl has the potential to enter estuarine/marine water bodies based on current usuage patterns that include coastal areas. Therefore, testing is required for Leptocheirus plumulosus , an estuarine/marine sediment

- dwelling invertebrate species

. Practical Utility of the Data How will the data be used? Data from sediment toxicity studies will be used to estimate potential risks to benthic organisms associated with uses of carfentrazone

- ethyl. The data will reduce uncertainties associated with the current risk assessment for benthic species and will improve our understanding of the potential effects of carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? Acceptable data for benthic organisms will reduce the uncertainty from previous assessments. If the data indicate that registered carfentrazone

- ethyl usage may pose a risk of adverse effects to non

- target benthic organisms above the Agency Level of Concern, the Agency may explore decision options to mitigat e this risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for carfentrazone

- ethyl which may otherwise be avoided, or which are unnecessarily severe.

Guideline Number: 850.2100 Study Title: Avian Acute Oral Toxicity Test Rationale for Requiring the Data Acceptable acute avian oral toxicity data were not submitted for a passerine species exposed to carfentrazone

- ethyl, which is now required under the 40 CFR Part 158 (CFR 40 2008) data requirements for conventional pesticides. The revised Part 158 data requ irements specify that acute avian oral toxicity data be submitted for either one waterfowl or one upland game species and one passerine species. Many passerine species utilizing forests, residential areas and surrounding areas, have the potential to be

ex posed to pesticides used in agricultural, forest, and residential settings. It is likely that, for most pesticide use patterns, passerines are more likely to be exposed to pesticides than upland game species and waterfowl. Because passerine species have higher metabolic rates due to their smaller sizes than either waterfowl or upland game bird species and because they may utilize different metabolic pathways, they may be more or less sensitive to carfentrazone

- ethyl. In order to properly characterize risk to passerines, an avian oral toxicity test is required for passerine birds. A passerine study protocol must be submitted for review by the Agency prior to initiation of the study.

### 66 Practical Utility of the Data How will the data be used? Acute avian oral toxicity data for passerine species will be used to refine the screening

- level risk assessment by determining whether there are differences in avian species sensitivity to carfentrazone

ethyl between currently tested passerine and upland g ame and/or waterfowl species that are beyond the simple allometric predictions currently employed in the absence of such passerine data. The current extrapolation method may be under

- or over

- estimating risks to passerines.

How could the data impact the A gency’s future decision

- making? If future risk assessments, including listed species assessments, are performed without these data, the Agency would have to assume that carfentrazone

- ethyl “may affect” listed birds directly (and listed species from other t axa indirectly), and use of carfentrazone

- ethyl and its formulated products may need to be restricted in areas where listed species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in complying with the En dangered Species Act and could result in restrictions for carfentrazone

- ethyl use that might prove to be unnecessary given data to address this area of uncertainty.

Guideline Number: 850. 41 00 Study Title: Tier 2 Seedling Emergence Test With TEP Rationale for Requiring the Data Available terrestrial plant toxicity studies were submitted using technical product, rather than a typical endues product, TEP; guidelines require that plant testing be conducted using TEP. The proposed rule establishing use of the TEP for vegetative vigor and seedling emergence studies states, “The TEP that contains the highest percentage of active ingredient, and/or is the most commonly used, would be required.” (FR Vol. 70 No. 47; March 11, 2005; 12289). Tier II seedli ng emergence and vegetative vigor studies on monocot and dicot test species should be repeated using TEP. Practical Utility of the Data How will the data be used? Toxicity data using TEP will be used to refine the screening

- level risk assessment by estimating potential risks to non

- target terrestrial plants associated with uses of carfentrazone

- ethyl. The data will reduce uncertainties associated with the current risk assessment for non

- target plants and will improve our understanding of the potential effects of carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? Acceptable data for terrestrial plants will reduce the uncertainty from previous assessments. If the data indicate that registered carfentrazone

- ethyl usage may pose a risk of adverse effects to non

- target terrestrial plants above the Agency Level of Concern, the Agency may explore decision options to mitigate this risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for carfentrazone

- ethyl which may otherwise be avoided, or which are unnecessarily severe.

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Guideline Number: 850 .4150 Study Title: Tier 2 Vegetative Vigor Test With TEP Rationale for Requiring the Data Available terrestrial plant toxicity studies were submitted using technical product, rather than a typical endues product, TEP; guidelines require that plant testing be conducted using TEP. The proposed rule establishing use of the TEP for vegetative vigor and seedling emergence studies states, “The TEP that contains the highest percentage of active ingredient, and/or is the most commonly used, would be requi red.” (FR Vol. 70 No. 47; March 11, 2005; 12289). Tier II seedling emergence and vegetative vigor studies on monocot and dicot test species should be repeated using TEP. Practical Utility of the Data How will the data be used? Toxicity data using TEP will be used to refine the screening

- level risk assessment by estimating potential risks to non

- target terrestrial plants associated with uses of carfentrazone

- ethyl. The data will reduce uncertainties associated with the current risk assessment for non

- target plants and will improve our understanding of the potential effects of carfentrazone

- ethyl.

How could the data impact the Agency’s future decision

- making? Acceptable data for terrestrial plants will reduce the uncertainty from previous assessments. If the data indicate that registered carfentrazone

- ethyl usage may pose a risk of adverse effects to non

- target terrestrial plants above the Agency Level of Concern, the Agency may explore decision options to mitigate this risk. The lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act, and could result in use restrictions for carfentrazone

- ethyl which may otherwise be avoided, or which are unnecessarily severe.