UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON D.C., 20460 

PC Code: 125203 

DP Barcode: D402548 

MEMORANDUM 

Date: 

Subject: 

To: 

From: 

Through: 

December 5, 2012 

Registration Review - Preliminary Problem Formulation for the 

Environmental Fate, Ecological Risk, Endangered Species, and Drinking 

Water Exposure Assessments for Clodinafop-propargyl 

Wilhelmena Livingston, Chemical Review Manager 

Risk Management and Implementation Branch 4 

Pesticide Re-evaluation Division 

Attached is the preliminary problem formulation for the ecological risk assessment to be 

conducted as part of the Registration Review of clodinafop-propargyl. 

Page 1 of50 
Page 2 of 50 

1. Introduction 

EFED evaluated the most recent ecological risk assessment and drinking water 

assessment for clodinafop-propargyl (PC Code 125203) in association with the updated 

toxicity, exposure, and usage information to determine if sufficient data are available and 

if further updates are needed to support registration review. The most recent ecological 

risk assessment is the 2000 New Chemical assessment (DP Barcode: D244333/ 

D246816) for the use of clodinafop-propargyl (also referred to as clodinafop) on wheat. 

For more information on the drinking water assessment, please see Section 2.2. The 

structure of clodinafop-propargyl and degradates of concern can be found in Appendix D. 

Clodinafop-propargyl is known as an aryloxyphenoxypropionic herbicide and is an 

acetyl-coenzyme A carboxylase (AC case) inhibitor and a systemic, post emergence 

herbicide used for post-emergent weed control of wild oats, green and yellow foxtail, and 

Persian darnel in wheat fields (including Durum). The herbicide inhibits the 

carboxylation of acetyl-CoA to malonyl-CoA that decreases fatty acid biosynthesis and 

prevents actively growing target weed species from maintaining their cell membrane 

integrity. The product is absorbed through the leaves and is rapidly translocated to the 

growing points of leaves and stems. 

 The formulation (clodinafop 2-E Herbicide, brand named HORIZON) of clodinafoppropargyl (22.3% a.i.) and inert ingredients (77.7%) may be applied to wheat by ground 

or air to control actively growing weeds. The wheat is protected from phytotoxic effects 

from clodinafop-propargyl by the presence of a safener, cloquintocet-mexyl (an inert 

ingredient). This particular formulated end-use product contains two pounds of active 

ingredient (lb a.i.) per gallon. The maximum application rate for this use is 0.0632 

pounds of active ingredient per acre (lb a.i./A) (USEPA 2000). The safener is applied in 

the herbicide end-use formulation at the rate of 0.0125 – 0.0157 lb safener./A when using 

3.2 or 4.0 fluid ounces of the product, respectively. Appendix A (BEAD memo) lists the 

use patterns of maximum exposure for the current uses of clodinafop-propargyl. 

Table 1: Screening Level Estimates of Agricultural Uses of Clodinafop-propargyl 

(125203) (January 18, 2012) 

Percent Crop Treated 

 Crop Lbs. A.I. Avg. Max. 

1 Barley + 1,000 <1 <2.5 

2 Wheat 90,000 5 10 

1) All numbers rounded. 

<500 Less than 500 pounds of active ingredient 

<2.5 Less than 2.5 percent of crop treated 

<1 Less than 1 percent of crop treated 

+ Crops not known to be listed on active end use product registrations or as Section 18 emergency 

exemptions for the period reported in this SLUA. 

2) SLUA data sources include: USDA-NASS (United States Department of Agriculture's National Agricultural Statistics 

Service) 

Private Pesticide Market Research 

3) These results reflect amalgamated data developed by the Agency and are releasable to the public. 
Page 3 of 50 

A Screening Level Usage Analysis conducted by the Agency indicates that the treated 

fraction of crops was reported to be 5% or less on average, with a maximum of 10%. 

There appears to be reported uses of clodinafop on barley, but this is not a known 

registered use for clodinafop. As a result, this use is deemed to be a misreported crop, or 

misuse, and will not be assessed in the risk assessment. The only known registered use 

for clodinafop is for wheat, which is classified as a terrestrial food and feed use. Please 

see Table 2 below for labeled uses. 

 

Table 2: Labeled Uses for Clodinafop-propargyl per LUIS Report (Created 6/1/2012) 

Use 

(Product 

Name, AI%, 

Formulation) 

Reg# 

Original 

(Product / 

A. I.) 

Max App 

Rate 

A. I. Max 

App Rate 

Max # 

Apps @ 

Max Rate 

/ CC 

Application 

Method 

Type 

Application 

Method 

Equipment 

Application 

Method 

Timing 

WHEAT 

(Discover NG/ 

Horizon NG, 

6.4% a.i., 

Emulsifiable 

Concentrate) 

100-1173 16 fl oz/ A 0.0632 lb a.i. / 

A 1 Broadcast. Aircraft, Ground Foliar, Tillering 

WHEAT 

(Discover 

Herbicide, 

22.3% a.i., 

Emulsifiable 

Concentrate) 

100-907 4 fl oz /A *0.0625 lb 

a.i./A 1 Broadcast. Aircraft, Ground 

Foliar, 

Postemergence 

*Based on the label, the product contains 2 lb a.i. per gallon. 

2. Conclusions from Previous Risk Assessments 

There has only been one ecological risk assessment performed on clodinafop; a new 

chemical assessment (USEPA 2000). Based on the new chemical assessment, acute risks 

to most organisms are not expected from ground application. Minimal acute risk is 

expected for clodinafop-propargyl to aquatic plants. However, it was determined that 

there was potential risk to federally-listed (i.e., listed as endangered or threatened) 

terrestrial plants inhabiting dry and semi-aquatic areas from aerial application, based on 

observed effects in the terrestrial plant toxicity test, (corn, oats, and ryegrass) exposed to 

the formulated product. Data to assess chronic risk to fish and aquatic invertebrates were 

incomplete, as there were no data for estuarine/marine fish and invertebrates, and only 

chronic freshwater invertebrate data were available for the acid CGA-193469, the 

primary degradate of clodinafop-propargyl. Given the available data, the new chemical 

assessment reported that there was minimal concern for chronic risk to freshwater 

organisms given that the EECs were far below the toxicity levels of concern. 

2.1. Ecological Risk Assessments 

Refer to Table 3 for the major ecological conclusions presented in the new chemical 

assessment. The check marks in the table refer to taxa expected to be at some level of risk 
Page 4 of 50 

as a result of the use on wheat. In addition, the check marks refer to acknowledged 

persistence of the chemical and potential ground water contamination as a result of the 

use on wheat. The results are based on all residues of concern (parent and the primary 

degradate CGA-193469). 

Table 3. Summary of Risk Concerns Identified for Clodinafop-propargyl in New Chemical 

Risk Assessment (DP Barcodes: D244333/ D246816) 

Birds Mammals Terrestrial 

Plants 

Terrestrial 

Inverts Fish Aquatic Inverts 

Aquatic 

Plants 

Ground water 

Contamination Persistence Degradate of Concern 

-- -- √a --b -- -- -- √c √d CGA193469 a

 The level of concern is exceeded for listed terrestrial plants when applying to adjacent dry and 

semi-aquatic areas by air. No level of concern is exceeded for non-listed terrestrial plants. b

 Based on an oral study on honey bees, clodinafop-propargyl is practically nontoxic to bees on an 

acute contact basis. 

c

 Clodinafop acid and its transformation products are highly mobile to mobile, persistent, and may 

reach ground water and surface water. 

d

 Clodinafop acid and its transformation products are persistent. 

Except for terrestrial plants, risk to terrestrial animals and aquatic plants and 

animals was expected to be minimal. Clodinafop-propargyl’s risk was only to 

terrestrial plants from aerial application. Cloquintocet-mexyl, a safener used in 

formulation with clodinafop-propargyl, had a minimal risk to animals and was 

presumed to have minimal risk to all plants. 

2.2. Drinking Water Exposure Assessments 

The most recent DWA was performed March 29, 2006 (DP 324688) and drinking water 

EECs are included in Table 4. In this DWA, the surface water values were modeled 

using PRZM EXAMS based on the North Dakota wheat scenario, with a percent crop 

area factor of 0.56. Concentrations in groundwater were estimated using the Tier 1 SCIGROW (screening) model. 

Table 4: EDWCs of the Combined Toxic Residues of Clodinafop-propargyl and Three Major 

Degradation Products1, 2

Surface Water

1-in-10 yr Peak 

μg/L (ppb). 

1-in-10 yr Annual Mean 

μg/L (ppb). 

Overall Annual Mean 

μg/L (ppb). 

3.3 2.5 1.7

Ground Water 

 Acute Chronic 

 0.227 0.227 1

 Degradates: (R)-2-[4-[(5-chloro-3-fluoro-2-pyridinyl)oxy]phenoxy]-propanoic acid, 5-chloro-3-fluoro-2(1H)-

pyridinone, and 4-[(5-chloro-3-fluoro-2-pyridinyl)oxy]phenol 

2

 Simulation used one aerial application of 0.0625 lb. a.i./acre, with the concentration values adjusted with the percent 

crop area factor (PCA) of 0.56. 

The Agency anticipates conducting an updated DWA to evaluate potential residues in 

groundwater, using the PRZM-GW model, which is replacing the SCI-GROW model. 
Page 5 of 50 

SCI-GROW is an empirical model based on a linear best fit of 13 prospective 

groundwater studies (one year of application). SCI-GROW was designed solely for use as 

a Tier I screening tool and does not have the capability to consider mitigating 

circumstances such as variability in leaching potential of different soils, weather 

(including rainfall), depth to aquifer, nor does it consider multiple years of application. 

To address these issues, the Agency developed PRZM-GW model. PRZM-GW is a onedimensional, finite-difference model that estimates the concentrations of pesticides in 

groundwater. It accounts for pesticide fate in the crop root zone by simulating pesticide 

transport and degradation through the soil profile after a pesticide is applied to an 

agricultural field. PRZM-GW permits the assessment of multiple years of pesticide 

application (up to 100 years) on a single site. 

2.3. Clean Water Act Programs 

Clodinafop 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 information provided at 

http://iaspub.epa.gov/waters10/attains_nation_cy.control?p_report_type=T#tmdl_by_poll

utant. 

The 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/oppfead1/cb/ppdc/2006/november06/session1-sop.pdf), in 

order to ensure they can be used quantitatively or qualitatively in pesticide risk 

assessments.
Page 6 of 50 

3. Environmental Fate and Transport 

The major route of dissipation for clodinafop-propargyl is de-esterification through 

abiotic hydrolysis and microbial mediated metabolism to form CGA-193469. Abiotic 

hydrolysis half-lives of clodinafop-propargyl are 18 days in pH 4 buffer solution, 26 days 

at pH 5, 6.1 days at pH 7, and 3.9 days at pH 9 (MRID 46012926). The major hydrolysis 

degradation product (>10% of applied radioactivity) was CGA-193469. Minor 

degradation products (<1% of applied radioactivity) in the hydrolysis studies include 

CGA-193468, CGA-215010, and CGA-302371. The aqueous photolysis half-life of 

clodinafop-propargyl ranges from 20.5 to 24.1 days in pH 5 buffer solution (MRID 

46012927 and 46012928). Photodegradation products include CGA-215010, CGA193468, CGA-302371, CGA-293358, and CGA-040725, NOA-428715, and CO2. In 

aerobic soil and aquatic metabolism studies, clodinafop-propargyl degrades rapidly 

(~t1/2=<1 day) to form CGA-193469 (MRID 46012931, 46012930). The batch 

equilibrium data for clodinafop-propargyl represent the adsorption and desorption 

behavior of CGA-193469 because of the rapid degradation of clodinafop-propargyl 

during equilibration (MRID 46012935) Rapid degradation of clodinafop-propargyl was 

confirmed in bare ground and cropped terrestrial field dissipation studies in North Dakota 

(MRID 46012939 and 46373401). 

The major degradation product and suspected active ingredient of clodinafop-propargyl 

is CGA-193469. Potential routes of dissipation for CGA-193469 are aerobic soil 

metabolism, leaching, and runoff. CGA-193469 had half-lives of 1 to 2.4 days in 

aerobic soil metabolism studies (MRID 46012931 and 46012930). In aerobic aquatic 

metabolism studies, CGA-193469 had a half-life of 41 days in the total water:sediment 

system (MRID 44399177). In anaerobic soil and aquatic environments, CGA-193469 is 

moderately persistent (MRID 44399177, 44399176, 46012932, 46012933). Because of 

the rapid and complete degradation of clodinafop-propargyl to form CGA-193469 in 

metabolism studies, the observed degradation products can be attributed to CGA-193469. 

Major degradation products (>10% of applied radioactivity) include CGA-193469, CGA302371, and CGA-193468. Minor degradation products (<10% of applied radioactivity) 

include CGA-215010, CGA -214111, and CGA-293356. CGA-193469 is expected to be 

mobile (Kfoc = 44-89) in soil and aquatic environments. Terrestrial field dissipation 

confirms the dissipation of CGA-193469 through degradation and leaching. CGA193469 had a field dissipation half-life of 7 days (MRID 46012939 and 46373401). 

Additionally, CGA-193469 was detected in a single replicate sample at 15-30 cm depth. 

Although clodinafop-propargyl has a log Kow exceeding 3, rapid degradation of 

clodinafop-propargyl in soil and aquatic environments is expected to limit 

bioaccumulation potential. The bioconcentration factor for clodinafop-propargyl was 26-

29 X for fillet, 494-496X for visceria, and 228-243X for whole fish from concentrations 

of 0.21 and 2.1 ug/L (MRID 44719601). Degradation products in fish tissues were 

identified as CGA-193469 (maximum concentration 61-582 ug/kg in viscera) and NOA428715 (maximum concentration 23.6-299 ug/kg in viscera). Bioconcentrated residues 

were rapidly and completely eliminated from fish tissues during a 14 day depuration 

period. 
Page 7 of 50 

Degradation Products 

The degradation products identified in each fate study and their maximum concentration 

formed are shown in Table 5. The environmental fate studies indicate the degradation 

products are mobile (Kfoc = 32-630) and more persistent than clodinafop-propargyl. 

Table 5: Degradation Product Formation in Environmental Fate Studies 

Degradation Product Study Maximum Percentage Formed 

CGA-193469 Hydrolysis 70-105% of applied (30 days) 

Photodegradation in Water 36.5% of applied (37 days) 

Aerobic Soil 79.9% of applied (2 hours) 

Aerobic Aquatic 97.6% of applied (1-14 days) 

Anaerobic Aquatic 102.3% of applied (28 days) 

CGA-193468 Hydrolysis 1.1% of applied 

Photodegradation in Water 8.06 of applied(37 days) 

Aerobic Soil 10.7% of applied (3 days) 

Anaerobic Aquatic 44.4% of applied 

CGA-215010 Hydrolysis 1.0% of applied 

Photodegradation in Water 0.57 of applied (37 days) 

Aerobic Soil 1.0% of applied 

Anaerobic Aquatic 4.9% of applied 

CGA-302371 Hydrolysis 1.1% of applied 

Aerobic Soil 22.6% of applied (14 days) 

Aerobic Aquatic 45.9% of applied (119 days) 

Anaerobic Aquatic 10.5% of applied (245 days) 

CGA-293358 Photodegradation in Water 2.58% of applied(37 days) 

CGA-040725 Photodegradation in Water 1.08% of applied (37 days) 

NOA-428705 Photodegradation in Water 3.76% of applied (37 days) 

CGA-214111 Aerobic Soil 5.6% of applied 

Anaerobic Aquatic 1.1% of applied 

The Health Effects Division previously identified the following residues of concern for 

clodinafop for the drinking water assessment: 

o (R)-2-[4-[(5-chloro-3-fluoro-2-pyridinyl)oxy]phenoxy]-2-propynyl ester 

propanoic acid (Parent, CAS # 105512-06-9, CGA-184927) 

o 2-[4-(5-chloro-3-fluoro-pyridin-2-yloxy)-phenoxy]-propionic acid (CAS # 

114420-56-3, CGA-193469) 

o 5-chloro-3-fluoro-2(1H)-pyridinone (CGA-302371) 

o 4-[(5-chloro-3-fluoro-2-pyridinyl)oxy]phenol (CGA-193468) 

These degradation products were considered in the most recent drinking water 

assessment, but for the ecological risk assessment the parent (CGA-184927) and the acid 

(CGA-193469) will be considered. Clodinafop belongs to a class of herbicides known as 

aryloxyphenoxypropionic herbicides. The active moiety for this class of compounds is 

present in the parent and the acid degradate (CGA-193469). However, the active 

functional group of the compound is not seen in the degradates of the acid (CGA-302371 

and CGA-193468). As a result, it is not believed these two degradates are as toxic as the 
Page 8 of 50 

parent and the acid; therefore, only the parent and the primary acid (CGA193469) will be 

considered as part of the total toxic residues (TTR) exposure in the ecological risk 

assessment. 

4. Receptors 

Table 7 and Table 7 provide a summary of the aquatic and terrestrial taxonomic groups, 

respectively, and most sensitive surrogate species tested to characterize the potential 

acute and chronic ecological effects of clodinafop-propargyl and its degradates (CGA302371, CGA-193469). Table 6 and Table 7 also provide a preliminary overview of the 

acute toxicity classifications of clodinafop-propargyl and its degradates to the tested 

species. 

In general, all endpoints in terms of the parent clodinafop-propargyl and its primary 

degradate (CGA-193469) will be assessed in terms of acid equivalence (a.e.) instead of 

active ingredient (a.i.), given the rapid degradation (approximately 6 days at pH 7 for 

aquatic systems – hydrolysis MRID 46012926, <0.25 hr in terrestrial systems -aerobic 

soil MRID 46012930) of the parent to CGA-193469 (DP 215199). The conversion is 

based on a ratio of molecular weights, not unlike the fate and toxicity bridging strategy 

utilized in a 2,4-D risk assessment completed in 2009 (US EPA, 

http://www.epa.gov/oppfead1/endanger/litstatus/effects/redleg-frog/2-4-d/analysis.pdf). 

None of the available data (although limited) indicate that any of the degradates are more 

toxic than the parent compound. Therefore, the assumption of equivalent or lesser 

toxicity of the degradate relative to the parent was made on the basis that the residues of 

concern are of equal or lesser toxicity than that of the parent compound. 

 

4.1. Effects to Aquatic Organisms 

Acute toxicity classifications indicate that the parent compound is highly toxic to 

freshwater fish and at most slightly to moderately toxic to freshwater invertebrates. The 

degradate CGA-193469 is at most moderately toxic to freshwater invertebrates. Available 

data (acute and chronic data on the freshwater invertebrate) on the parent, clodinafoppropargyl and the primary degradate, CGA-193469, suggest that the relative toxicity is 

uncertain because the data on the parent is either based on a non-definitive value (acute) 

or is not available (i.e., classified as invalid, chronic). A comparison of non-vascular 

aquatic plant data suggests that the green algae (S. subspicatus) is less sensitive to the 

degradate CGA-302371 than it is to the parent compound; however, there are no data 

available on the primary degradate, CGA-193469. No chronic data are available for the 

freshwater fish and freshwater invertebrates on the parent. 
Page 9 of 50 

Table 6. Summary of the Most Sensitive Endpoints from Available Aquatic Toxicity 

Studies for Clodinafop-propargyl and its Degradates (CGA-193469, CGA-302371) 

Taxonomic 

Group 

Study 

Type % a.i. Surrogate Species 

Toxicity 

Value 

MRID and 

Classification 

Acute 

Toxicity 

Classification 

Freshwater 

fish1

Acute 

93.7 

Bluegill sunfish 

(Lepomis 

macrochirus) 

LC50: 0.24 

mg total/L 

44399113 

Supplemental2 Highly toxic 

99 

(CGA302371) 

Rainbow trout 

(Oncorhynchus 

mykiss) 

LC50 >95.4 

mg a.i./L 

44399108 

Supplemental3 

Practically 

non-toxic 

Chronic 

(Early 

LifeStage) 

No Data --- --- -- -- 

Freshwater 

invertebrates 

Acute 

94.7 

Waterflea 

(Daphnia 

magna) 

LC50: >2.0 

mg a.i./L 

44561102 

Supplemental4

Moderately 

toxic 

86.4 

(CGA193469) 

LC50: >9.2 

mg a.i./L 

44399116 

Supplemental4 

Moderately 

toxic 

99 

(CGA302371) 

LC50: >98.9 

mg a.i./L 

44399117 

Supplemental4 

Practically 

non-toxic 

Chronic 

99.3 

(CGA193469) 

NOAEC: 

2.6 mg 

a.i./L 

LOAEC: 

10.3 mg 

a.i./L 

44399121 

Supplemental4 

Not 

applicable 

Estuarine/ 

marine fish Acute No Data --- --- -- -- 

Estuarine/ 

marine 

invertebrates 

Acute No Data --- --- -- -- 

Aquatic plants 

and algae 

Vascular 94.2 Duckweed 

(Lemna gibba) 

EC50: >2.4 

mg a.i./L 

44399165 

Acceptable 

Moderately 

toxic (at 

most) 

Nonvascular 

94.2 

Freshwater 

diatom 

(Navicula 

pelliculosa) 

EC50: 3.0 

mg a.i./L 

44399166 

Acceptable 

Moderately 

toxic 

99 

(CGA302371) 

Green Algae 

(Scenedesmus 

subspicatus) 

EC50: 30.6 

mg a.i./L 

44399161 

Supplemental5 Slightly toxic 

1 Freshwater fish may be surrogates for aquatic-phase amphibians. 2

 A definite chemical analysis was not determined by centrifuging the test material 

3

 Only 7 fish were used per concentration 

4

 pH and water hardness exceeded the recommended range of the EPA guidelines 

5

 Study terminated at 72-hr instead of 96-hr 
Page 10 of 50 

4.2. Effects to Terrestrial Organisms 

Acute toxicity classifications indicate that the parent compound is slightly toxic to birds 

on an oral basis and practically non-toxic to birds on a dietary basis. Similarly, the parent 

compound is classified as practically non-toxic to honeybees on an acute contact basis. 

Uncertainty in the available data stems from the following: 1) an acute oral passerine 

study is not available; 2) no toxicity data are available for degradates (except for the 

terrestrial plant tier II studies on CGA-193469). No open literature toxicity data were 

submitted or identified; however, a couple of terrestrial plant studies were completed in 

2002 and reviewed by EFED in 2004, in response to requested data identified in the 2000 

new chemical assessment. The data request was for a seedling emergence study and a 

vegetative vigor study using the acid degradate without a safener. Indeed, the tier II 

studies were conducted with 100% CGA-193469; seedling emergence (MRID 46012902) 

and vegetative vigor (MRID 46012901). A comparison of terrestrial plant data (TEP 

versus degradate CGA-193469) is also inconclusive. Firstly, the dicots were deemed 

insensitive to the test compounds in all terrestrial plant studies (seedling emergence and 

vegetative vigor). With regard to monocots, heightened sensitivity (in ryegrass) to the 

degradate than to the TEP is observed in the seedling emergence studies, but reduced 

sensitivity (in corn) to the degradate relative to the TEP is observed in the vegetative 

vigor studies. 

Table 7. Summary of the Most Sensitive Endpoints from Terrestrial Toxicity Studies for 

Clodinafop-propargyl and its Degradate CGA-193469 

Taxonomic 

Group 

Study Type % a.i. Surrogate 

Species 

Toxicity 

Value 

MRID and 

Classification 

Acute 

Toxicity 

Classification 

Birds1

Acute oral 93.7 

Northern 

bobwhite 

quail 

(Colinus 

virginianus) 

LD50: 1455 

mg a.i./kg 

44399106 

Acceptable Slightly toxic 

Sub-acute 

dietary 93.7 

Northern 

bobwhite 

quail 

LC50: >51202

mg a.i./kg

44399110 

Acceptable 

Practically 

nontoxic 

Chronic 94.2 

Northern 

bobwhite 

quail 

NOAEC & 

LOAEC: > 

500 mg 

a.i./kg 

(no 

significant 

reduction at 

the highest 

concentration 

tested) 

44399112 

Acceptable Not 

applicable 

Mammals Acute Oral 93.7 

Laboratory 

rat (Rattus 

norvegicus) 

LD50: 1392 

mg a.i./kg 

(male) 

44399124 Slightly toxic 
Page 11 of 50 

Taxonomic 

Group 

Study Type % a.i. Surrogate 

Species 

Toxicity 

Value 

MRID and 

Classification 

Acute 

Toxicity 

Classification 

Acute 

Inhalation 93.7 

 Laboratory 

rat (Rattus 

norvegicus) 

LC50: 2325 

mg/m3

 

(2.3 mg/L) 

44399126 

(4-hr 

exposure) 

-- 

Chronic (2-

gen) 93.7 Lab rat 

NOAEC: 50 

mg a.i./kg 

LOAEC: 

5003

 mg 

a.i./kg 

44399146 Not 

applicable 

Insects Acute contact 93.7 

Honey bee 

(Apis 

mellifera) 

LD50: >100 

g a.i./bee 

44399167 

Acceptable 

Practically 

nontoxic 

Terrestrial 

plants 

Seedling 

Emergence 

(Tier II) 

TEP4

Monocot – 

Ryegrass 

EC25: 0.031 

lbs a.i./A 

NOAEC: 

0.023 lbs 

a.i./A 

Endpoint: 

shoot weight 

44555002 

Acceptable 

Not 

applicable 

Dicot5 - 

None 

EC25: >0.091 

lbs a.i./A 

NOAEC: 

0.091 lbs 

a.i./A 

CGA193469 

(Deg.) 

Monocot – 

Ryegrass 

EC25: 0.017 

lbs a.i./A 

NOAEC: 

0.00788 lbs 

a.i./A 

Endpoint: 

dry weight 

46012902 

Acceptable 

Not 

applicable 

Dicot6 – 

None 

EC25: >0.063 

lbs a.i./A 

NOAEC: 

0.063 lbs 

a.i./A 

Vegetative 

vigor (Tier II) 

TEP4

Monocot - 

Corn 

EC25: 0.0048 

lbs a.i./A 

NOAEC: 

0.0028 lbs 

a.i./A 

Endpoint: 

phytotoxicity 

44555002 

Acceptable 

Not 

applicable 

Dicot7 - 

None 

EC25: >0.091 

lbs a.i./A 

NOAEC: 

0.091 lbs 

a.i./A 
Page 12 of 50 

Taxonomic 

Group 

Study Type % a.i. Surrogate 

Species 

Toxicity 

Value 

MRID and 

Classification 

Acute 

Toxicity 

Classification 

CGA193469 

(Deg.) 

Monocot - 

Corn 

EC25: 0.031 

lbs a.i./A 

NOAEC: 

0.0158 lbs 

a.i./A 

Endpoint: 

dry weight 

46012901 

Acceptable 

Not 

applicable 

Dicot8 - 

None 

EC25: >0.063 

lbs a.i./A 

NOAEC: 

0.063 lbs 

a.i./A 1 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 2

 One bird perished at 325 mg a.i./kg on day 1 

3

 Parent: based on decrease in body weight gain, reduced food consumption, increased liver and kidney weights and 

histopathological changes in the liver 

4

 CGA-184927 (22.3% a.i.); CGA-185072 (5.79% a.i.) 

5

 Dicots tested include cabbage, lettuce, tomato, soybean, carrot, cucumber 

6

 Dicots tested include carrot, cucumber, lettuce, radish, soybean, tomato 

7 Dicots tested include cabbage, lettuce, radish, soybean, carrot, cucumber 

8

 Dicots tested include carrot, cucumber, lettuce, radish, soybean, tomato 
Page 13 of 50 

4.3. Ecological Incidents 

Preliminary reviews of the Ecological Incident Information System (EIIS, version 2.1) 

and the Avian Incident Monitoring System (AIMS)1

 were conducted on August 22, 2012. 

A total of 2 EIIS incidents associated with clodinafop-propargyl use were located. In 

addition to the incidents recorded in EIIS and AIMS, additional incidents have been 

reported to the Agency in aggregated incident reports, within the US EPA Office of 

Pesticide Programs Incident Data System. Pesticide registrants report certain types of 

incidents to the Agency as aggregate counts of incidents occurring per product per 

quarter. However, for clodinafop-propargyl no aggregate incident reports were available. 

2 EIIS Incident reports: Plants

Incident ID: I014266-002

The ‘possible’ spray (drift) from unspecified misuse of clodinafop-propargyl led to this 

terrestrial plant incident (possibly strawberries) in the summer of 2003 in Manitoba, 

Canada. 

Incident ID: I016904-001

The ‘probable’ accidental ground spray (direct treatment) from accidental exposure or 

misuse of clodinafop-propargyl led to this terrestrial plant incident (150 acres of corn) in 

the summer of 2005 in North Dakota. 

5. Conceptual Model 

The parent, clodinafop, rapidly degrades to the acid equivalent, and the acid degrades to 

form the remaining residues of concern. The conceptual model will consider the acid 

(CGA-193469), as well as remaining parent compound if any, to determine a total toxic 

residue (TTR) approach (see Section 6: Analysis Plan for how that will be done). The 

environmental fate properties of TTR indicate that direct spray, spray drift, leaching to 

ground water, surface water exposure, and runoff represent potential transport 

mechanisms of clodinafop to aquatic and terrestrial organisms. Clodinafop acid and its 

transformation products are highly mobile to mobile, persistent, and may reach ground 

water and surface water. 

Additional Terrestrial Exposure Pathways 

Inhalation Exposure

The Screening Tool for Inhalation Risk (STIR v.1.0, November 19, 2010) was used to 

calculate an upper bound estimate of exposure using clodinafop-propargyl’s vapor 

pressure (2.39 x 10-8 mm Hg at 25o

C) and molecular weight (349.74 g/mol) for vapor 

phase exposure as well as the maximum application rate (0.0632 lb a.i./A, which is the 

maximum single as well as seasonal application rate to wheat) and method of application 

(ground spray applications; note: altering the method of application to aerial spray did not 

 

1

 http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm 
Page 14 of 50 

change the conclusions) for spray drift. STIR incorporates results from several toxicity 

studies including acute oral and inhalation rat toxicity endpoints obtained from the “sixpack” of core studies, which are a series of six guideline studies that are submitted to the 

Registration Division of the Office of Pesticide Programs on laboratory rats for technical 

and formulated products of a pesticide (male rat acute oral (TGAI): LD50 = 1392 mg 

a.i./kg-bw, MRID 44399124; rat inhalation (TGAI): 4-hour LC50 = 2.3 mg/L, MRID 

44399126). In addition, the most sensitive acute oral avian toxicity endpoint (Northern 

bobwhite quail, LD50 = 1455 mg a.i./kg-bw, MRID 44399106) was used. Based on the 

results of the STIR model, inhalation exposure alone was not determined to be a potential 

pathway of concern for avian or mammalian species on an acute basis as a result of 

ground or aerial spray applications of clodinafop-propargyl on wheat. For raw 

input/output, see Appendix C. 

Inhalation exposure via spray drift and/or vapor-phase of the pesticide alone does not 

appear to be of concern. The analysis of the inhalation route in STIR does not consider 

that aggregation with other exposure pathways such as dietary, dermal, or drinking water 

may contribute to a total exposure that has a potential for effects to non-target animals. 

However, the Agency does consider the relative importance of other routes of exposure in 

situations where data indicate that pesticide exposures through other routes may be 

potentially significant contributors to wildlife risk (USEPA, 2004). Detailed information 

about STIR v.1.0, as well as the tool, can be found on the EPA’s website at: 

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial. 

Drinking Water Exposure

Drinking water for the purposes of terrestrial organism risk assessment is defined as that 

portion of an organism’s daily water intake that is not met by dietary or metabolic 

sources and must be consumed in liquid form. Typical drinking water sources for 

wildlife in pesticide use areas may include on-field puddles, irrigation equipment (e.g., 

drip irrigation in grape cultivation), dew deposited on treated plants, and off-field surface 

water exposures. 

The Screening Imbibition Program (SIP v.1.0, Released June 15, 2010) was used to 

calculate an upper bound estimate of exposure using clodinafop-propargyl’s solubility in 

water (4 mg/L at 25o

C). Using TGAI clodinafop-propargyl data for the most sensitive 

acute (LD50 = 1455 mg a.i./kg-bw for the Northern bobwhite quail, MRID 44399106) and 

chronic (NOAEC > 500 mg a.i./kg-diet, Northern bobwhite quail, MRID 44399112) 

avian toxicity endpoints and the most sensitive acute (LD50 = 1392 mg a.i./kg-bw, male 

rat, MRID 44399124) and chronic (reproduction NOAEC = 50 mg/kg-diet, which was 

converted to 2.5 mg/kg-bw/day based on a recalculation in T-REX using standard FDA 

lab rat conversion, MRID 44399146) mammalian toxicity endpoints. Drinking water 

exposure alone was determined not to be a potential pathway of concern for avian and 

mammalian species on an acute and chronic basis. For raw input/output, see Appendix 

C. Detailed information about the SIP v.1.0, as well as the tool, can be found on the 

EPA’s website at http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial. For 

raw input/output, see Appendix C. 
Page 15 of 50 

6. Analysis Plan 

The total toxic residues approach will be used for the clodinafop assessment when 

determining the Environmental fate data parameters for modeling using the Guidance for 

Selecting Input Parameters in Modeling the Environmental Fate and Transport of 

Pesticides, Version 2.1, October 22, 2009 and the draft Guidance for Modeling Pesticides 

Total Toxic Residues (TTR) May 20, 2009. Using this total toxic residue approach 

assumes the residues of concern are of equal toxicity to the parent compound. 

The TTR approach will be used to determine the input parameters for aquatic and 

terrestrial exposure. Given the limited toxicity data to reliably compare the relative 

toxicity between the parent and its primary degradate (the acid CGA-193469), the 

assumption of equivalent or lesser toxicity of the degradate relative to the parent was 

made on the basis of the available acute and chronic data. 

Likewise, for both aquatic and terrestrial exposure, an acid equivalence to the degradate 

(CGA-194369) will be calculated. The acid equivalence calculation is a conversion from 

active ingredient to acid equivalent using the relationship between the molecular weight 

of the parent and its primary degradate (the acid CGA-193469) in order to normalize the 

toxicity data to the same concentration units. A memo written in 2006 (DP 215199) 

stated that since “the reported environmental fate half-lives of clodinafop... [without 

TTR]...are very short, EFED believes that the major degradate (CGA-194369), may 

actually be the active ingredient.” Given the rapid degradation of the parent to the acid 

(approximately 6 days at pH 7 for aquatic systems – hydrolysis MRID 46012926, <0.25 

hrs in terrestrial systems -aerobic soil MRID 46012930). 

Therefore, all inputs for modeling, in addition to performing TTR, will be converted to 

the acid equivalence for the degradate CGA-194369. In general, all toxicity endpoints in 

terms of the parent clodinafop-propargyl and CGA-193469 will be reported in terms of 

acid equivalence (a.e.) instead of active ingredient (a.i.), given the rapid degradation 

(approximately 6 days at pH 7 for aquatic systems – hydrolysis MRID 46012926, <0.25 

hrs in terrestrial systems -aerobic soil MRID 46012930) of the parent to CGA-193469 

(DP 215199). 

A selection of environmental fate and transport properties of clodinafop and degradate of 

concern are summarized in Table 8. For chemical structures see Appendix D. A detailed 

list of all studies and acceptability status can be found in Section 7. 

Table 8: Chemical Properties and Environmental Fate Parameters of Clodinafop 

and Degradate of Concern 

Parameter Value Source

Selected Physical/Chemical Parameters 

Molecular Weight (Parent) 349.74 Sigma-Aldrich Co. 

Vapor pressure 2.39 x 10-8 mmHg at 25 C (parent) 44399101 
Page 16 of 50 

Parameter Value Source

Aqueous solubility 4.0 mg/L at pH 7, 25 C (parent) 44399101 

Henry’s Law Constant (20°C) 2.75 x 10-9 atm x m3/mole calculated 

Persistence

Hydrolysis half-life (25C) TTR: stable (total toxic residues) 46012926

Aqueous photolysis half-life (25C) 

52 days (total toxic residues, study submitted 

under 46012928) 

46012927, 

46012928 

Aerobic soil metabolism half-life (25°C) Total toxic residues: 96.6 and 67.9 days 

46012930, 

46012931, 

44399177 

Anaerobic aquatic metabolism half-life (20-

29C) 

stable (total toxic residues**) 46012933, 

46012933 

Aerobic aquatic metabolism half-life 

[dissipation half-life A] (25C) 

CGA-193469 half-life = 41 days in the total 

water:sediment system MRID 44399177 

Mobility

Koc 

285 (average of all Koc values from 

TTRs[55,89,43,32,46,58,52,70,50,81,62,72,6

1,98,32,71,87,96,76,832,2133,647,998,718,5

77]) 

46012935, 

46012934, 

46012937, 

46012936 

* while the half-life only includes only two of the three degradates of concern, most of the uncertainty associated with using this value 

is captured by calculating the 90% upper bound on the mean 

 ** t 1⁄2 = 965 days calculated 

Since the parent degrades rapidly to the acid and the acid is an ionic compound that is, by 

nature, not expected to bioaccumulate, it is not necessary to run KABAM because 

accumulation in fish tissues is not expected. 

 
Page 17 of 50 

6.1. Stressors of Concern 

The stressors of concern for aquatic and terrestrial organisms are the parent compound 

and the acid degradate (CGA-193469). It is believed that the degradates CGA-193468 

and CGA-302371, which are degradates formed from the acid, are less toxic than the 

parent and the acid. Clodinafop belongs to a class of herbicides known as 

aryloxyphenoxypropionic herbicides. The active moiety for this class of compounds is 

present in the parent and the acid degradate (CGA-193469). However, the active 

functional group of the compound is not seen in the degradates of the acid (CGA-302371 

and CGA-193468). As a result, it is not believed these two degradates are as toxic as the 

parent and the acid. 

The clodinafop residues of concern may be reevaluated pending receipt and review of 

additional environmental fate and toxicity data. Safeners are currently not included in the 

assessment. 

6.2. Measures of Exposure 

EFED will use standard available models to evaluate potential exposures to aquatic and 

terrestrial organisms as described at 

http://www.epa.gov/pesticides/science/models_db.htm. 

Screening level calculations have suggested that drinking water and inhalation exposure 

pathways for wildlife are likely not of concern (Appendix C). 

In addition to the routes of exposure described above, irrigation water exposure/analysis 

may be conducted as clodinafop residues/degradates are persistent and mobile and may 

contaminate irrigation water. 

6.3. Measures of Effect 

Toxicity data presented in Section 3 of this problem formulation will be used to calculate 

risk quotients. In general, all endpoints in terms of the parent clodinafop-propargyl and 

CGA-193469 will be reported in terms of acid equivalence (a.e.) instead of active 

ingredient (a.i.), given the rapid degradation (approximately 6 days at pH 7 for aquatic 

systems – hydrolysis MRID 46012926, <0.25 hrs in terrestrial systems -aerobic soil 

MRID 46012930) of the parent to CGA-193469 (DP 215199). Any additional 

information submitted by the registrant or found in the open literature prior to conduct of 

the risk assessment will also be considered. The open literature studies are identified 

using EPA’s ECOTOXicology database (ECOTOX) (USEPA, 2007c), which employs a 

literature search engine for locating chemical toxicity data for aquatic life, terrestrial 

plants, and wildlife. 
Page 18 of 50 

6.4. 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 pesticides in registration review. These assessments will 

be conducted in accordance with standard EPA procedures and good scientific judgment. 

6.5. Endocrine Disruptor Screening Program 

As required by FIFRA and FFDCA, EPA reviews numerous studies to assess potential 

adverse outcomes from exposure to chemicals. Collectively, these studies include acute, 

subchronic and chronic toxicity, including assessments of carcinogenicity, neurotoxicity, 

developmental, reproductive, and general or systemic toxicity. These studies include 

endpoints which may be susceptible to endocrine influence, including effects on 

endocrine target organ histopathology, organ weights, estrus cyclicity, sexual maturation, 

fertility, pregnancy rates, reproductive loss, and sex ratios in offspring. For ecological 

hazard assessments, EPA evaluates acute tests and chronic studies that assess growth, 

developmental and reproductive effects in different taxonomic groups. As part of the 

registration review decision, EPA reviewed these data and selected the most sensitive 

endpoints for relevant risk assessment scenarios from the existing hazard database. 

However, as required by FFDCA section 408(p), clodinafop-propargyl is subject to the 

endocrine screening part of the Endocrine Disruptor Screening Program (EDSP). 

EPA has developed the EDSP to determine whether certain substances (including 

pesticide active and other ingredients) may have an effect in humans or wildlife similar to 

an effect 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 assays 

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 systems 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, and establish a 

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

Under FFDCA section 408(p), the Agency must screen all pesticide chemicals. 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. 

Clodinafop-propargyl is not among the group of 58 pesticide active ingredients on the 

initial list to be screened under the EDSP. Accordingly, as part of registration review, 

EPA will issue future EDSP orders/data call-ins, requiring the submission of EDSP 

screening assays for clodinafop-propargyl. For further information on the status of the 

EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test 
Page 19 of 50 

guidelines and the Tier 1 screening battery, please visit our website: 

http://www.epa.gov/endo/. 

7. Preliminary Identification of Data Gaps 

7.1. Environmental Fate

Table 9 identifies environmental fate studies, as well as study classifications, and 

whether or not further data are needed in order to support risk assessment. 

Table 9. Submitted Environmental Fate Data for Clodinafop 

OCSPP Guideline Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed to 

conduct risk 

assessment? 

Current 

Additional Data 

Need 

835.2120 Hydrolysis 44399169 Unacceptable (no) 

46012926 Acceptable -- 

835.2240 

44399170 Unacceptable 

(no) Aqueous 

photolysis -- 46012927 Acceptable 

46012928 Acceptable 

835.2410 Soil photolysis 44399171 Acceptable (no) -- 

835.4100 Aerobic soil 

metabolism 

44399174 Supplemental 

(no) -- 

44399172 Supplemental 

44399173 Supplemental 

44399176 Supplemental 

46012931 Acceptable 

46012931 Acceptable 

835.4200 

Anaerobic soil 

metabolism 44399176 Supplemental (no) 

A new anaerobic 

soil metabolism 

study is not 

expected to provide 

useful information 

for this risk 

assessment. 

835.4300 

Aerobic aquatic 

metabolism 

44387449 Supplemental 

(no) -- 44399177 Supplemental 

44399178 Supplemental 

835.4400 Anaerobic aquatic 

metabolism 

46012933 Acceptable 

(no) -- 44387448 Supplemental 

4399176 Supplemental 
Page 20 of 50 

OCSPP Guideline Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed to 

conduct risk 

assessment? 

Current 

Additional Data 

Need 

46012932 Acceptable 

4399177 Supplemental 

835.1230/835.1240 

Adsorption/ 

desorption and 

leaching 

46012937 Acceptable 

(CGA-193469) 

(no) 

-- 

44831201 Supplemental 

(CGA-193469) 

44831202 Supplemental 

(CGA-302371) 

46012935 Supplemental 

46012936 Supplemental 

44399179 Unacceptable 

44399180 Unacceptable 

46012934 Supplemental 

44399182 Supplemental 

44399181 Unacceptable 

835.1410 Volatility – 

laboratory Not required 

835.6100 

Terrestrial field 

dissipation 

46012939/ 

46373401 

Supplemental 

for CGA193469 

(no) 

-- 

Analytical 

method in soil 46012938 Acceptable 

835.6200 

Aquatic field 

dissipation 

Not required 

Analytical 

method in water 
Page 21 of 50 

OCSPP Guideline Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed to 

conduct risk 

assessment? 

Current 

Additional Data 

Need 

850.1730 Fish 

bioconcentration 

44719601/ 

44719602 Supplemental (no) -- 

7.2 Ecological Effects 

Table , Table and 12 identify ecological effects studies as well as study classifications 

and whether or not further data are needed in order to support risk assessment. 

Rationales for the additional data requested are presented in the preliminary identification 

of data gaps section. 

Toxicity data for the parent compound are available for birds, mammals, terrestrial 

invertebrates, terrestrial plants, vascular and non-vascular aquatic plants, freshwater fish 

and freshwater invertebrates. For degradates CGA-302371 and CGA-193469, acute and 

chronic toxicity data are available for freshwater fish and invertebrates as well as a green 

algae study. Data gaps are identified and summarized in subsequent tables.

Currently, there are no data are available for estuarine/marine fish or invertebrates on an 

acute or chronic basis. To determine if data are needed, EPA conducted a cursory 

analysis to estimate how much more sensitive estuarine/marine animals would need to be 

in order to exceed the level of concern. In the case for fish, based on the peak surface 

water estimated environmental concentration (EEC) of 2.5 ppb, in order to exceed the 

listed acute LOC of 0.05 for fish and considering the LC50 of 0.24 ppm for freshwater 

fish (bluegill sunfish, MRID 44399113), the marine/estuarine endpoint would need to be 

over 1,900 times more sensitive in order to exceed the LOC. For acute exposure to 

invertebrates, even when assuming that the lowest reported endpoint of >2.0 ppm as a 

definitive value, the marine/estuarine invertebrate endpoint would need to be 

approximately 16,000 times more sensitive in order to exceed the LOC. Therefore, at this 

time, EFED does not recommend requesting toxicity data to evaluate potential toxicity to 

estuarine/marine animals at this time, and intends to use the available freshwater animal 

data as a surrogate to assess potential risk to all aquatic animals. 
Page 22 of 50 

Table 10. Submitted Aquatic Ecological Effects Data for Clodinafop-propargyl 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

(%purity) 

Are data 

needed to 

conduct 

risk 

assessment? 

Comments 

 850.1010 Freshwater 

invertebrate 

acute toxicity 

44399115 Supplemental 

(TGAI, 93.7%)

No A definitive endpoint was not 

determined. There is 

unexplained variability across 

studies in the freshwater 

invertebrate data and no clear 

explanation as to presence of 

mortality at lower 

concentrations.

44561102 Supplemental 

(TGAI, 94.7%) 

850.1025 

850.1035 

850.1045 

850.1055 

Saltwater 

invertebrate 

acute toxicity 

None N/A No -- 

 850.1075 Freshwater 

fish acute 

toxicity 

44561101 Acceptable 

(TGAI, 94.7%) 

No -- 

44399114 Supplemental 

(TGAI, 93.7%) 

A definitive chemical analysis 

was not determined by 

centrifuging the test material. 44399113 Supplemental 

(TGAI, 93.7%) 

 850.1075 Saltwater fish 

acute toxicity 

None N/A No -- 

 850.1300 Freshwater 

invertebrate 

life cycle 

44399119 Invalid No A definite LOAEC could not 

be produced because test 

concentrations were only 

measured for 3 days instead of 

21 days 

44399120 Invalid Test solutions contained 

precipitate but were not 

centrifuged before chemical 

analysis; the LOAEC was at 

the lowest test level, therefore 

the NOAEC could not be 

produced. 

 850.1350 Saltwater 

invertebrates 

life cycle 

None N/A No -- 

 850.1400 Freshwater 

fish 

early-life stage 

None N/A Yes Study is recommended 

preferably on a species already 

tested in an acute study. 

Non-GLN Long-term 

lethality 

toxicity 

44399118 Supplemental 

(TGAI, 93.7%) 

No Rainbow trout 21-day toxicity 

study. 
Page 23 of 50 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

(%purity) 

Are data 

needed to 

conduct 

risk 

assessment? 

Comments 

 850.1400 Saltwater fish 

early-life stage 

None N/A No -- 

 850.1500 Fish life cycle None N/A No -- 

850.4400 Aquatic plant 

growth: 

Tier II vascular 

plants 

44399165 Acceptable No -- 

850.5400 Aquatic Plant 

Growth: 

Tier II nonvascular plants 

44399162 Acceptable 

(TGAI, 94.2%) 

No -- 

44399163 Supplemental 

(TGAI, 94.2%) 

Study terminated at 72-h 

instead of 96-h. 

44561104 Acceptable 

(TGAI, 94.7%) 

-- 

44399166 Acceptable 

(TGAI, 94.2%) 

-- 

44399164 Supplemental 

(TGAI, 94.2%) 

Initial numbers of cells 

exceeded the recommended 

range of 3,000-10,000 cells. 

44561103 Acceptable 

(TGAI, 94.7%) 

-- 

Table 11. Submitted Terrestrial Ecological Effects Data for Clodinafop-propargyl

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed for 

risk 

assessment? 

Comments 

 850.2100 Avian oral 

toxicity 

44399106 Acceptable 

(TGAI, 93.7%) 

Yes Data is available for Northern 

bobwhite quail and mallard 

duck, but it is not available for 

a passerine species, which is 

required under 40 CFR Part 

158. 

44399107 Acceptable 

(TGAI, 93.7%) 

 850.2200 Avian dietary 

toxicity 

44399110 Acceptable 

(TGAI, 93.7%) 

No -- 

44399109 Acceptable 

(TGAI, 93.7%) 

 850.2300 Avian 

reproduction 

44399112 Acceptable 

(TGAI, 94.2%) 

No -- 
Page 24 of 50 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed for 

risk 

assessment? 

Comments 

44399111 Invalid Total number of eggs laid and 

eggs laid per hen are 

significantly lower in the 

control group; thus, the power 

of the test is insufficient to 

determine a statistically 

significant endpoint. 

 850.3020 Honey bee 

acute contact 

toxicity 

44399167 Acceptable 

(TGAI, 93.7%) 

No -- 

850.3030 Honey bee 

residue on 

foliage 

None N/A No -- 

 850.3040 Field testing 

for 

pollinators 

None N/A No -- 

850.4100 Terrestrial 

plant toxicity: 

Tier II 

seedling 

emergence 

44555002 Acceptable 

(TEP, 2 a.i.) 

No CGA-184927 (22.3%); 

CGA-185072 (5.79%) 

46012902 Acceptable 

(TGAI, deg)1 

CGA-193469 (100%) 

850.4150 Terrestrial 

plant toxicity: 

Tier II 

vegetative 

vigor 

44555002 Acceptable 

(TEP, 2 a.i.) 

No CGA-184927 (22.3%); 

CGA-185072 (5.79%) 

46012901 Acceptable 

(TGAI, deg)1 

CGA-193469 (100%) 

1 These terrestrial plant studies were completed in 2002 and reviewed by EFED in 2004, which address the 

data request of the 2000 new chemical assessment. The data request was for a seedling emergence and a 

vegetative vigor study using a degradate without a safener. The prior data gap has been fulfilled. 

 
Page 25 of 50 

Table 12. Aquatic Ecological Effects Data for Clodinafop-propargyl Degradates, 

CGA-302371 and CGA-193469 

OCSPP 

Guideline 

Data 

Requirement 

Submitted 

Studies 

(MRID) 

Study 

Classifications 

Are data 

needed for 

risk 

assessment? 

Comments 

 850.1010 Freshwater 

invertebrate 

acute toxicity 

44399116 Supplemental 

(TGAI, deg, 

86.4%) 

No A definitive endpoint was not 

determined. Test compound: 

degradate CGA-193469. 

44399117 Supplemental 

(TGAI, deg, 

99%) 

No pH and water hardness exceeded 

the recommended range of the 

EPA guidelines requirements. 

Test compound: CGA-302371. 

850.1075 Freshwater 

fish acute 

toxicity 

44399108 Supplemental 

(TGAI, deg, 

99%) 

No Only 7 fish were used per 

concentration. Test compound: 

CGA-302371. 

 850.1300 Freshwater 

invertebrate 

life cycle 

44399121 Supplemental 

(TGAI, deg, 

99.3%) 

No pH and water hardness exceeded 

the recommended range of the 

EPA guidelines requirements. 

Test compound: CGA-193469. 

850.5400 Aquatic Plant 

Growth: 

Tier II nonvascular 

plants 

44399161 Supplemental 

(TGAI, 99%) 

No Test compound: CGA-302371. 

Several ecological effects data gaps were noted in the 2000 New Chemical Risk 

Assessment for clodinafop 2E Herbicide (HORIZON) (DP Barcode: D244333, 

D246816), including an avian reproduction toxicity study. The remaining data gaps were 

identified for this problem formulation. 

Active ingredient: Clodinafop-propargyl 

Avian Reproduction (OCSPP 850.2300): 

Subdivision E requires two avian reproduction studies for a complete risk 

characterization of the active ingredient, but the requirement is only partially fulfilled 

Given that chronic risk to birds appeared to be minimal [NOAEC = 500 mg a.i./kg-diet 

(the highest concentration tested) ], a mallard reproduction study was considered a 

guideline requirement, but at the time of the new chemical assessment (USEPA 2000), 

the study was not recommended to be requested because it was not considered of high 

value. The weight of evidence does not warrant the need for an additional avian 

reproduction study. 

OCSPP 850.2100 Avian oral toxicity: 

Two acceptable oral toxicity studies are available, one each for the Northern bobwhite 

quail (MRID 44399106) and mallard duck (MRID 44399107). However, avian acute oral 

toxicity data are not available for passerines, which are required under 40 CFR Part 158 

(July 1, 2010). The 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. Though 
Page 26 of 50 

all four, submitted acute avian studies (oral, MRID 44399106 and 44399107, as well as 

dietary, MRID 44399110 and 44399109) indicated low toxicity to the parent clodinafoppropargyl, the passerine test species may indicate greater sensitivity. For acute and listed 

species LOC exceedances to take place, acute dose-based toxicity endpoints (LD50) for 

passerines (approximate body weight of 20g; consumption of short grass) would need to 

be on the order of 34.54 mg a.i./kg-bw and 172.7 mg a.i./kg-bw, respectively (assuming a 

single application rate of 0.0632 lbs a.i./A and default half-life of 35 days; using T-REX 

1.5). Given that little is known about the relative toxicities of upland game birds and 

waterfowl to passerines, the probability of achieving this value is uncertain. However, 

given that the 14-day NOAEL for the Northern bobwhite acute oral study (521 mg 

a.i./kg-bw; MRID 44399106) was on the order of the potential level at which listed 

species LOC exceedances might be observed (i.e., at LD50 of 172.7 mg a.i./kg-bw), a 

request for a passerine study is warranted. 

Passerines are the most common birds (in terms of numbers and number of species) in the 

United States. Many utilize agricultural fields, forests, residential areas and surrounding 

areas, and, therefore, have the potential to be exposed to pesticides used in agricultural, 

forest, and residential settings. It is likely that, for the requested use patterns, passerines 

are more likely to be exposed to clodinafop-propargyl than upland game species and 

waterfowl. Passerines are smaller and have a higher energy requirement than larger-sized 

birds. As such, passerines may be more sensitive than other birds. A protocol is 

requested prior to submission of the study. If oral acute toxicity data are not submitted 

for passerines, risk cannot be precluded for passerine species. 

OCSPP 850.1400 Chronic Toxicity to Freshwater Fish (Fish Early-life Stage)

Given the broadcast (ground/aerial) applications of clodinafop-propargyl (currently 

registered for wheat), it is possible for the parent and its degradates to enter the aquatic 

ecosystem via runoff and drift; the compounds are persistent as they are stable to 

hydrolysis and aqueous photolysis. A chronic freshwater fish study is not available for 

clodinafop-propargyl or its degradates. The lack of these data is a noted uncertainty in the 

2000 new chemical risk assessment. A fish early-life stage toxicity study conducted with 

the parent compound is recommended, preferably on a species already tested in the acute 

freshwater fish studies. 

8. References 

USEPA. 2000. New Chemical: Clodinafop 2E Herbicide (HORIZON). Chemical: 125203 

/ Company: 000100 Novartis Crop Protection. DP Barcode: D244333/ D246816. 

Office of Prevention, Pesticides, and Toxic Substances. Office of Pesticide 

Programs. 
Page 27 of 50 

Appendices 

– Appendix A: BEAD Report and SLUA 

– Appendix B: OPPIN Bibliography 

– Appendix C: STIR/SIP model outputs 

– Appendix D: Chemical Structures 

– Appendix E: Additional Discussion on Available Aquatic Toxicity Data 

on Degradates 

 
Page 28 of 50 

Appendix A: BEAD Report and SLUA 

EFED Label Data Report Ingredient: Clodinafop-propargyl (125203) Current As of Date: 6/1/2012 NDC - No Dosage Conversion ; NS - Not Specified 

Site Desc Use Group Desc Reg# LUIS Accepted Date AI% Formulation Desc Product Name Original (Product / A. I.) Max App Rate A. I. Max App Rate Max # Apps @ Max Rate / CC 

M

WHEAT TERRESTRIAL FOOD + FEED 100- 1173 10/3/2008 6.4 EC DISCOVER NG/HORIZON NG 16 fl oz/ 1 a .0632 lb / a 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 1173 10/3/2008 6.4 EC DISCOVER NG/HORIZON NG 16 fl oz/ 1 a .0632 lb / a 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 1173 10/3/2008 6.4 EC DISCOVER NG/HORIZON NG 16 fl oz/ 1 a .0632 lb / a 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 1173 10/3/2008 6.4 EC DISCOVER NG/HORIZON NG 16 fl oz/ 1 a .0632 lb / a 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 907 9/19/2008 22.3 EC DISCOVER HERBICIDE 1 unspecified NDC 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 907 9/19/2008 22.3 EC DISCOVER HERBICIDE 1 unspecified NDC 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 907 9/19/2008 22.3 EC DISCOVER HERBICIDE 1 unspecified NDC 1 BWHEAT TERRESTRIAL FOOD + FEED 100- 907 9/19/2008 22.3 EC DISCOVER HERBICIDE 1 unspecified NDC 1 B
Page 29 of 50 

Clodinafop-propargyl (125203) 

Screening Level Usage Analysis (SLUA) 

Date: January 18, 2012 

What is a Screening Level Usage Analysis (SLUA)? 

 Available estimates of pesticide usage data for a particular active ingredient 

that is used on agricultural crops in the United States.

 Pesticide usage data obtained from various sources. The data are then 

merged, averaged, and rounded so that the presented information is not 

proprietary, business confidential, or trade secret. 

What does it contain? 

 Pesticide usage data for a single active ingredient only.

 Agricultural use sites (crops) that the pesticide is reported to be used on. 

 Available pesticide usage information from U.S. states that produce 80% or 

more of a crop, in most cases, or less than 80%, in rare cases, depending on 

the scope of the survey and available resources.

 Annual percent of crop treated (average & maximum) for each agricultural 

crop.

 Average annual pounds of the pesticide applied for each agricultural crop (i.e., 

for the states surveyed, not for the entire United States). 

What assumptions can I make about the reported data? 

 Average pounds of active ingredient applied - Values are calculated by 

merging pesticide usage data sources together; averaging across all 

observations, then rounding. Note: If the estimated value is less than 500, 

then that value is labeled <500. Estimated values between 500 & <1,000,000 

are rounded to 1 significant digit. Estimated values of 1,000,000 or greater 

are rounded to 2 significant digits.) 

 Average percent of crop treated - Values are calculated by merging data 

sources together; averaging by year, averaging across all years, & rounding to 

the nearest multiple of 5. Note: If the estimated value is less than 2.5, then 

the value is labeled <2.5. If the estimated value is less than 1, then the value 

is labeled <1. 

 Maximum percent of crop treated - Value is the single maximum value 

reported across all data sources, across all years, & rounded up to the nearest 

multiple of 5. Note: If the estimated value is less than 2.5, then the value is 

labeled <2.5.

What are the data sources used?

 USDA-NASS (United States Department of Agriculture’s National 

Agricultural Statistics Service) – pesticide usage data from 2003 to 2010. 

 Private pesticide market research – pesticide usage data from 2003 to 2010.

 California Department of Pesticide Regulation (DPR) Pesticide Use 

Reporting (PUR) data for 2003 to 2009. 

What are the limitations to the data? 

 Additional registered uses may exist but are not included because the 

available surveys do not report usage (e.g., small acreage crops). 
Page 30 of 50 

 Lack of reported usage data for the pesticide on a crop does not imply zero 

usage. 

 Usage data on a particular site may be noted in data sources, but not 

quantified. In these instances, the site would not be reported in the SLUA. 

 Non-agricultural use sites (e.g., turf, post-harvest, mosquito control, etc.) are 

not reported in the SLUA. A separate request must be made to receive these 

estimates. 

 Some sites show some use, even though they are not on the label. This usage 

could be due to various factors, including, but not limited to Section 18 

requests, existing stocks of the chemical, data collection errors, and 

experimental use permits (EUPs). 
Page 31 of 50 

 January 18, 2012 

Screening Level Estimates of Agricultural Uses of Clodinafop-propargyl (125203) 

Sorted Alphabetically

 

Percent Crop Ttd.

 

 Crop Lbs. A.I. Avg. Max.

1 Barley + 1,000 <1 <2.5

2 Wheat 90,000 5 10

All numbers rounded. 

<500 Less than 500 pounds of active ingredient 

<2.5 Less than 2.5 percent of crop treated 

<1 Less than 1 percent of crop treated 

 

+ Crops not known to be listed on active end use product registrations or as 

Section 18 emergency 

exemptions for the period reported in this SLUA. 

 

 

SLUA data sources include: 

USDA-NASS (United States Department of Agriculture's National Agricultural 

Statistics Service) 

Private Pesticide Market Research 

These results reflect amalgamated data developed by the Agency and are releasable to the 

public. 

 
Page 32 of 50 

Appendix B: OPPIN Bibliography 

Fate Bibliography: 

Bibliography 

161-1 Hydrolysis 

MRID Citation Reference 

44387442 Keller, A. (1991) Hydrolysis of (inert ingredient) Under Laboratory 

Conditions: Lab Project Number: 14/91: 388-91: 89AK01. Unpublished 

study prepared by Novartis Crop Protection AG. 39 p. 

44399169 Keller, A. (1987) Hydrolysis of CGA-184927 Under Laboratory 

Conditions: Lab Project Number: 31/87: 185-87: 86AK01. Unpublished 

study prepared by Novartis Crop Protection AG. 37 p. 

46012926 Spare, W. (2001) Aqueous Hydrolysis of (Carbon 14)-CGA-184927 

Under Laboratory Conditions: Final Report. Project Number: 003/035, 

66/00. Unpublished study prepared by Exygen Research. 415 p. 

161-2 Photodegradation-water 

MRID Citation Reference 

44387443 Schaffer, A. (1991) Aqueous Photolysis of (inert ingredient) Under 

Laboratory Conditions: Lab Project Number: 21/91: 381-91: 90AS01. 

Unpublished study prepared by Novartis Crop Protection AG. 45 p. 

44399170 Keller, A. (1990) Photolysis of CGA-184927 in Aqueous Solutions 

Under Laboratory Conditions: Lab Project Number: 5/90: 350-90: 

87AK11. Unpublished study prepared by Novartis Crop Protection AG. 

35 p. 

45059201 Phaff, R. (1995) Rate and Quantum Yield of the Direct 

Phototransformation of CGA-193469 Under Laboratory Conditions in 

Water: Final Report: Lab Project Number: 525-94: 94RP04. 

Unpublished study prepared by Novartis Crop Protection AG. 30 p. 

46012927 Anderson, W. (2002) Photodegradation of (Carbon 14)-CGA-184927 in 

pH Buffered Solution Under Artificial Light: Final Report. Project 

Number: 82/00. Unpublished study prepared by Syngenta Crop 

Protection, Inc. 130 p. 

46012928 Anderson, W. (2003) Photodegradation of (Carbon 14)[Phenyl]-CGA-
Page 33 of 50 

184927 in pH 5 Buffered Solution Under Artificial Light: Final Report. 

Project Number: 19/02. Unpublished study prepared by Syngenta Crop 

Protection, Inc. 133 p. 

161-3 Photodegradation-soil 

MRID Citation Reference 

44387444 Keller, A. (1993) Soil Photolysis of (inert ingredient) Under Laboratory 

Conditions: Lab Project Number: 02/93: 613-93: 92AK02. Unpublished 

study prepared by Novartis Crop Protection AG. 45 p. 

44399171 Keller, A. (1993) Soil Photolysis of CGA-184927 Under Laboratory 

Conditions: Lab Project Number: 01/93: 607-93: 92AK01. Unpublished 

study prepared by Novartis Crop Protection AG. 48 p. 

162-1 Aerobic soil metabolism 

MRID Citation Reference 

44387445 Keller, A. (1991) Degradation of (inert ingredient) in Two Soils Under 

Aerobic Laboratory Conditions at 20 (degree): Lab Project Number: 

89AK05: 390-91. Unpublished study prepared by Novartis Crop 

Protection AG. 19 p. 

44387446 Keller, A. (1992) Rate of Degradation of (inert ingredient) in Aerobic 

Soil at Various Conditions: Lab Project Number: 23/92: 509-92: 

91AK01. Unpublished study prepared by Novartis Crop Protection AG. 

31 p. 

44387447 Keller, A. (1992) Degradation of (inert ingredient) in Soil under Aerobic, 

Aerobic/Anaerobic and Sterile/Aerobic Conditions at 20 (degree): Lab 

Project Number: 35/92: 508-92: 90AK01. Unpublished study prepared 

by Novartis Crop Protection AG. 48 p. 

44399172 Keller, A. (1992) Degradation of CGA-184927 in Three Soils Under 

Aerobic Conditions at 20 (degrees centigrade): Lab Project Number: 

07/92: 500-92: 90AK04. Unpublished study prepared by Novartis Crop 

Protection AG. 31 p. 

44399173 Keller, A. (1989) Degradation of CGA-184927 in Soil Under Aerobic 

Conditions at 15 (degrees centigrade): Lab Project Number: 27/89: 334-

89: 87AK13. Unpublished study prepared by Novartis Crop Protection 

AG. 25 p. 

44399174 Keller, A. (1989) Degradation of (carbon 14)-Pyridine-Labeled CGA-
Page 34 of 50 

184927 in Aerobic Soil at 25 (degrees centigrade): Lab Project Number: 

25/89: 337-89: 87AK12. Unpublished study prepared by Novartis Crop 

Protection AG. 30 p. 

44399176 Keller, A. (1989) Degradation of (carbon 14)-Phenyl-Labeled CGA184927 in Aerobic, Aerobic/Anaerobic and Sterile/Aerobic Soil at 25 

(degrees centigrade): Lab Project Number: 26/89: 335-89: 87AK12. 

Unpublished study prepared by Novartis Crop Protection AG. 37 p. 

46012930 Spare, W. (2003) Aerobic Soil Metabolism of (Carbon 14)-PyridinylLabeled CGA-184927: Final Report. Project Number: 003/039, 2218/01. 

Unpublished study prepared by Exygen Research. 490 p. 

46012931 Spare, W. (2003) Aerobic Soil Metabolism of (Carbon 14)-PhenylLabeled CGA-184927: Final Report. Project Number: 003/038, 207/01. 

Unpublished study prepared by Exygen Research. 412 p. 

162-2 Anaerobic soil metabolism 

MRID Citation Reference 

44387447 Keller, A. (1992) Degradation of (inert ingredient) in Soil under Aerobic, 

Aerobic/Anaerobic and Sterile/Aerobic Conditions at 20 (degree): Lab 

Project Number: 35/92: 508-92: 90AK01. Unpublished study prepared 

by Novartis Crop Protection AG. 48 p. 

44399176 Keller, A. (1989) Degradation of (carbon 14)-Phenyl-Labeled CGA184927 in Aerobic, Aerobic/Anaerobic and Sterile/Aerobic Soil at 25 

(degrees centigrade): Lab Project Number: 26/89: 335-89: 87AK12. 

Unpublished study prepared by Novartis Crop Protection AG. 37 p. 

162-3 Anaerobic aquatic metab. 

MRID Citation Reference 

44387448 Keller, A. (1992) Rate of Degradation of (inert ingredient) Under 

Aerobic, Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures: Lab Project Number: 08/93: 612-93: 91AK02. 

Unpublished study prepared by Novartis Crop Protection AG. 47 p. 

44399177 Keller, A. (1993) Rate of Degradation of CGA-184927 Under Aerobic, 

Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures (Including Amendment 1): Lab Project Number: 07/93: 

608-93: 91AK04. Unpublished study prepared by Novartis Crop 

Protection AG. 63 p. 
Page 35 of 50 

45059203 Keller, A. (1995) Rate of Degradation of CGA-184927 Under Aerobic, 

Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures: Final Report Amendment: Lab Project Number: 07/93: 

608-93: 91AK04. Unpublished study prepared by Novartis Crop 

Protection AG. 19 p. 

46012932 Concha, M. (2003) CGA-184927: Anaerobic Aquatic Metabolism of 

[Pyridinyl-2,6](Carbon 14)-CGA-184927 in a Sediment/Water System: 

Final Report. Project Number: 1059W, 80/00. Unpublished study 

prepared by PTRL West, Inc. 266 p. 

46012933 Concha, M. (2003) CGA-184927: Anaerobic Aquatic Metabolism of 

[Phenyl-U](Carbon 14)-CGA-184927 in a Sediment/Water System: 

Final Report. Project Number: 1109W, 35/02. Unpublished study 

prepared by PTRL West, Inc. 246 p. 

162-4 Aerobic aquatic metab. 

MRID Citation Reference 

44387448 Keller, A. (1992) Rate of Degradation of (inert ingredient) Under 

Aerobic, Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures: Lab Project Number: 08/93: 612-93: 91AK02. 

Unpublished study prepared by Novartis Crop Protection AG. 47 p. 

44387449 Reischmann, F. (1996) Metabolism of (inert ingredient) under Aerobic 

Conditions in Aquatic Systems: Lab Project Number: 95RF02: 460/96. 

Unpublished study prepared by Novartis Crop Protection AG. 71 p. 

44399177 Keller, A. (1993) Rate of Degradation of CGA-184927 Under Aerobic, 

Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures (Including Amendment 1): Lab Project Number: 07/93: 

608-93: 91AK04. Unpublished study prepared by Novartis Crop 

Protection AG. 63 p. 

44399178 Reischmann, F. (1996) Metabolism of (Carbon 14)-Phenyl and (Carbon 

14)-Pyridine CGA-184927 under Aerobic Conditions in Aquatic 

Systems: Lab Project Nos. 95RF03; 459-96. Unpublished study prepared 

by Novartis Crop Protection AG. 89 p. 

45059203 Keller, A. (1995) Rate of Degradation of CGA-184927 Under Aerobic, 

Anaerobic and Sterile Conditions in an Aquatic System at Two 

Temperatures: Final Report Amendment: Lab Project Number: 07/93: 

608-93: 91AK04. Unpublished study prepared by Novartis Crop 

Protection AG. 19 p. 

163-1 Leach/adsorp/desorption 
Page 36 of 50 

MRID Citation Reference 

44387450 Keller, A. (1991) Leaching Characteristics of Aged Residues of (inert 

ingredient) in Two Soils after 200 mm of Artificial Rainfall: Lab Project 

Number: 24/91: 386-91: 90AK02/A. Unpublished study prepared by 

Novartis Crop Protection AG. 33 p. 

44387451 Keller, A. (1991) Leaching Model Study with (inert ingredient) in Four 

Soil Types: Lab Project Number: 89AK03: 389-91. Unpublished study 

prepared by Novartis Crop Protection AG. 36 p. 

44387452 Keller, A. (1991) Leaching Characteristics of Aged Residues of (inert 

ingredient) in Two Soils after 508 mm of Artificial Rainfall: Lab Project 

Number: 25/91: 383-91: 90AK02/B. Unpublished study prepared by 

Novartis Crop Protection AG. 35 p. 

44387453 Keller, A. (1990) Adsorption / Desorption of (inert ingredient) in 

Various Soil Types: Lab Project Number: 41/90: 354-90: 89AK02. 

Unpublished study prepared by Novartis Crop Protection AG. 34 p. 

44399179 Keller, A. (1990) Leaching Characteristics of Aged Residues of (carbon 

14)-CGA-184927 in Two Soil Types After 508 mm Rainfall: Lab Project 

Number: 10/90: 346-90: 88AK09-2. Unpublished study prepared by 

Novartis Crop Protection AG. 37 p. 

44399180 Keller, A. (1990) Leaching Characteristics of Aged Residues of (carbon 

14)-CGA-184927 in Two Soil Types After 200 mm Rainfall: Lab Project 

Number: 6/90: 352-90: 88AK09-1. Unpublished study prepared by 

Novartis Crop Protection AG. 35 p. 

44399181 Keller, A. (1989) Adsorption/Desorption of CGA-184927 in Various 

Soil Types: Lab Project Number: 29/89: 331-89: 88AK12. Unpublished 

study prepared by Novartis Crop Protection AG. 34 p. 

44399182 Keller, A. (1989) Leaching Model Study with CGA-184927 in Four Soil 

Types: Lab Project Number: 23/89: 336-89: 88AK02. Unpublished study 

prepared by Novartis Crop Protection AG. 29 p. 

44831201 Hill, A. (1994) CGA 193469: Adsorption/Desorption in Three Soils: 

Final Report: Lab Project Number: HE 380/221: 910-99: 380/221-1015. 

Unpublished study prepared by Hazleton Europe. 84 p. 

44831202 Hill, A. (1994) CGA 302371: Adsorption/Desorption in Three Soils: 

Final Report: Lab Project Number: 380/222: 911-99: P9093D. 

Unpublished study prepared by Hazleton Europe. 86 p. 

46012934 Spare, W. (2003) Adsorption and Desorption Study to Determine the 

Mobility and Distribution of [2,6-(Carbon 14)]CGA-302371 in Soil: 

Final Report. Project Number: EXP/003/042, 003/042, 72/00. 

Unpublished study prepared by Exygen Research. 296 p. 
Page 37 of 50 

46012935 Spare, W. (2003) Adsorption and Desorption Study to Determine the 

Mobility and Distribution of [Phenyl-U-(Carbon 14)]CGA-184927 in 

Soil: Final Report. Project Number: 003/041, 69/00, 02P/003/041. 

Unpublished study prepared by Exygen Research. 306 p. 

46012936 Spare, W. (2003) Adsorption and Desorption Study to Determine the 

Mobility and Distribution of [Phenyl-U-(Carbon 14)]CGA-193468 in 

Soil: Final Report. Project Number: 003/046, 31/03, EXP/003/046. 

Unpublished study prepared by Exygen Research. 303 p. 

46012937 Spare, W. (2003) Adsorption and Desorption Study to Determine the 

Mobility and Distribution of [Phenyl-U-(Carbon 14)]CGA-193469. 

Project Number: 003/043, EXP/003/043, 71/00. Unpublished study 

prepared by Exygen Research. 304 p. 

164-1 Terrestrial field dissipation 

MRID Citation Reference 

44399183 Purdy, J. (1997) Detailed Study Summary Covering CGA-184927 and 

(Inert) Soil Dissipation Studies in Canada: Lab Project Number: 500-97. 

Unpublished study prepared by Novartis Crop Protection, Inc. 4 p. 

44399184 Purdy, J. (1993) Horizon 240EC (Topik 240EC) (CGA-184927 

(Clodinafop-Propargyl) + (Inert Ingredient) (Includes Volume 1: 

Environmental Chemistry and Fate Assessment and Volume 2: Soil 

Dissipation Studies in Canada): Lab Project Nos. 1603/91; 1603/92: 626-

93. Unpublished study prepared by Novartis Crop Protection AG. 143 p. 

44399188 Altenburger, E. (1991) Determination of Residues of Metabolites CGA193469 and CGA-153433 by Liquid Chromatography (HPLC): Lab 

Project Number: REM 138.04: 515-97. Unpublished study prepared by 

Novartis Crop Protection AG. 19 p. 

44399189 Mair, P. (1992) Determination of Residues of Metabolites CGA-193469 

and CGA-153433 by Liquid Chromatography (HPLC): Lab Project 

Number: REM 138.07: 517-97. Unpublished study prepared by Novartis 

Crop Protection AG. 16 p. 

44646101 Nelson, S.; Bruns, G. (1998) Method of Analysis for the Determination 

of CGA 184927 and the Acid Metabolite CGA 193469 by GC/MS: Lab 

Project Number: 321-98: 147.00. Unpublished study prepared by EnviroTest Laboratories. 40 p. 

44646102 Nelson, S.; Bruns, G. (1998) Method of Analysis for the Determination 

of CGA 302371 (UE Metabolite) in Soil by LC/MS: Lab Project 

Number: MS 47.00: 320-98. Unpublished study prepared by Enviro-Test 

Laboratories. 23 p. 
Page 38 of 50 

46012938 Chamkasem, N. (2002) Analytical Method 38-01 for the Determination 

of CGA-184927 and its Degradates CGA-193468, CGA-193469 and 

CGA-302371 and (Inert Ingredient) and its Degradate (Inert Ingredient) 

in Soil by High Performance Liquid Chromatography with Mass 

Spectrometric Detection. Project Number: 38/01. Unpublished study 

prepared by Syngenta Crop Protection, Inc. 102 p. 

46012939 Speth, R. (2003) Terrestrial Field Dissipation of Discover Herbicide 

(CGA-184927) on Bare Soil and Spring Wheat in North Dakota: Final 

Report. Project Number: 36/01, 46966, 14663/1. Unpublished study 

prepared by Analytical Bio-Chemistry Labs., Inc., ABC Laboratories, 

Inc. and Ricerca Biosciences, LLC. 510 p. 

46373401 Speth, R.; Cassidy, P. (2004) Stability of CGA-184927, CGA-193468, 

CGA-193469, CGA-302371, CGA-185072 and CGA-153433 in Soil 

Under Freezer Storage Conditions. Project Number: 14900, 1823/02. 

Unpublished study prepared by Ricerca Biosciences, LLC. 110 p. 

164-2 Aquatic field dissipation 

MRID Citation Reference 

45059202 Ellgehausen, H. (1999) Calculation of the Degradation Kinetics of 

Metabolites CGA-193469, CGA-193468 and CGA-302371 in Aquatic 

Systems: Final Report: Lab Project Number: 99EEH05: 1218-99. 

Unpublished study prepared by Novartis Crop Protection AG. 28 p. 

165-4 Bioaccumulation in fish 

MRID Citation Reference 

44387455 Burri, R. (1993) Accumulation and Elimination of (inert ingredient) by 

Bluegill Sunfish in a Dynamic Flow-through System: Lab Project 

Number: 313143: 628-93. Unpublished study prepared by RCC 

Umweltchemie AG. 103 p. 

44719601 Peters, J. (1998) Uptake, Depuration, and Bioconcentration of (carbon 

14)-Pyridinyl-CGA-184927 in Fish Under Flow-Through Test 

Conditions: Lab Project Number: ABR-98070: 61-98: 44374. 

Unpublished study prepared by Novartis Crop Protection, Inc., ABC 

Laboratories, Inc. and Covance Laboratories. 456 p. 

860.1380 Storage stability data 
Page 39 of 50 

MRID Citation Reference 

46012916 Hamilton, L. (2001) Residue Stability of CGA-184927 and (Inert 

Ingredient) and Their Metabolites, CGA-193469 and (Inert Ingredient), 

Fortified into Wheat Forage and Hay Under Freezer Storage Conditions: 

Final Report. Project Number: 128/99. Unpublished study prepared by 

Syngenta Crop Protection, Inc. 120 p. 

46012917 Hamilton, L. (2001) Residue Stability of CGA-193469 and (Inert 

Ingredient), Fortified into Wheat Germ Under Freezer Storage 

Conditions: Final Report. Project Number: 224/01. Unpublished study 

prepared by Syngenta Crop Protection, Inc. 47 p. 

Eco Bibliography: 

125203 Clodinafop-propargyl Eco Effects Bibliography 

71-1 Avian Single Dose Oral Toxicity 

MRID Citation Reference 

44387406 Hakin, B.; Johnson, A.; Anderson, A. et al. (1988) Acute Oral Toxicity 

(LD50) of (inert ingredient) to the Bobwhite Quail: Lab Project Number: 

CBG 471/89310: 215-88. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 39 p. 

44387407 Hakin, B.; Norman, A.; Anderson, A. et al. (1989) Acute Oral Toxicity 

(LD50) of (inert ingredient) to the Mallard Duck: Lab Project Number: 

CBG 472/89311: 344-89. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 37 p. 

44399106 Hakin, B.; Norman, A.; Anderson, A. et al. (1990) Acute Oral Toxicity 

(LD50) of CGA-184927 to the Bobwhite Quail: Lab Project Number: 

CBG 467/89396: 341-89. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 39 p. 

44399107 Hakin, B.; Rodgers, M.; Norman, A. et al. (1990) Acute Oral Toxicity 

(LD50) of CGA-184927 to the Mallard Duck: Lab Project Number: CBG 

468/89444: 342-89. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 40 p. 

71-2 Avian Dietary Toxicity 

MRID Citation Reference 

44387408 Hakin, B.; Norman, A.; Rodgers, A. et al. (1990) The Subacute Dietary 

Toxicity (LD50) of (inert ingredient) to the Mallard Duck: Lab Project 
Page 40 of 50 

Number: CBG 470/89102: 346-89. Unpublished study prepared by 

Huntingdon Research Centre, Ltd. 36 p. 

44387409 Hakin, B.; Norman, A.; Rodgers, A. et al. (1989) The Dietary Toxicity 

(LD50) of (inert ingredient) to the Bobwhite Quail: Lab Project Number: 

CBG 469/89703: 345-89. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 38 p. 

44399109 Hakin, B.; Norman, A.; Rodgers, M. et al. (1989) The Subacute Dietary 

Toxicity (LC50) of CGA-184927 to Mallard Duck: Lab Project Number: 

466/89118: 212-88: CBG/466. Unpublished study prepared by 

Huntingdon Research Centre, Ltd. 37 p. 

44399110 Hakin, B.; Rodgers, M.; Norman, A. et al. (1990) The Dietary Toxicity 

(LC50) of CGA-184927 to the Bobwhite Quail: Lab Project Number: 

CBG 465/89445: 343-89. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 38 p. 

71-4 Avian Reproduction 

MRID Citation Reference 

44399111 Johnson, A.; Healey, G.; Anderson, A. et al. (1993) CGA-184927--

Mallard Duck Dietary Reproduction Study: Lab Project Number: CBG 

547/931488: 512-92. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 178 p. 

44399112 Johnson, A.; Healey, G.; Anderson, A. et al. (1993) CGA-184927--

Bobwhite Quail Dietary Reproduction Study: Lab Project Number: CBG 

545/931487: 513-92. Unpublished study prepared by Huntingdon 

Research Centre, Ltd. 245 p. 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 

44387410 Rufli, H.; Lanter, F.; de Morsier, A. (1988) Report on the Test for Acute 

Toxicity of (inert ingredient) to Bluegill (Lepomis macrochirus): Lab 

Project Number: 871686: 217-88. Unpublished study prepared by CibaGeigy, Ltd. 17 p. 

44387411 Rufli, H.; Dieterle, R.; de Morsier, A. (1988) Report on the Test for 

Acute Toxicity of (inert ingredient) to Rainbow Trout (Salmo gairdneri): 

Lab Project Number: 871684: 218-88. Unpublished study prepared by 

Ciba-Geigy, Ltd. 17 p. 

44399108 Rufli, R.; Bader, U.; Gonzalez-Valero, J. (1995) Acute Toxicity of CGA302371 (Metabolite of CGA-184927) to Rainbow Trout (Oncorhynchus 

mykiss) in the Static System: Lab Project Number: 951511: 752-95. 
Page 41 of 50 

Unpublished study prepared by Ciba-Geigy, Ltd. 30 p. 

44399113 Rufli, H.; Heinemann, G.; de Morsier, A. (1989) Report for Acute 

Toxicity of CGA-184927 Technical to Bluegill (Lepomis macrochirus): 

Lab Project Number: 881071: 213-88. Unpublished study prepared by 

Ciba-Geigy, Ltd. 21 p. 

44399114 Rufli, H.; Dieterle, R.; de Morsier, A. (1989) Test for Acute Toxicity of 

CGA-184927 Technical to Rainbow Trout (Salmo gairdneri): Lab 

Project Number: 881069: 214-88. Unpublished study prepared by CibaGeigy, Ltd. 24 p. 

44399118 Vial, A.; Bader, U.; de Morsier, A. (1990) Report on the Prolonged 

Toxicity Test of CGA-184927 Technical to Rainbow Trout: Lab Project 

Number: 901140: 356-90. Unpublished study prepared by Ciba-Geigy 

Ltd. 36 p. 

44561101 Ward, T.; Magazu, J.; Boeri, R. (1998) Acute Toxicity Of CGA-184927 

to the Rainbow Trout, Oncorhynchus mykiss: Lab Project Number: 

1422-NO. Unpublished study prepared by T.R. Wilbury Labs, Inc. 29 p. 

72-2 Acute Toxicity to Freshwater Invertebrates 

MRID Citation Reference 

44387412 Rufli, H.; Lanter, F.; de Morsier, A. (1988) Report on the Test for Acute 

Toxicity of (inert ingredient) to Daphnia magna: Lab Project Number: 

871681: 216-88. Unpublished study prepared by Ciba-Geigy, Ltd. 18 p. 

44399115 Rufli, H.; Dieterle, R.; de Morsier, A. (1988) Report on the Test for 

Acute Toxicity of CGA-184927 Technical to Daphnia magna: Lab 

Project Number: 871491: 201-87: 740/87. Unpublished study prepared 

by Ciba-Geigy, Ltd. 19 p. 

44399116 Putt, A.; Brown, M.; Kendall, T. et al. (1993) CGA-193469--Acute 

Toxicity to Daphnids (Daphnia magna) Under Static Renewal 

Conditions: Lab Project Number: 93-12-5071: 629-93: 

1781.0893.6386.110. Unpublished study prepared by Springborn 

Labs., Inc. 72 p. 

44399117 Neumann, C.; Bader, U.; Gonzalez-Valero, J. (1996) Acute Toxicity 

Test of CGA-302371 (Metabolite of CGA-184927) to the Cladoceran 

Daphnia magna Under Static Conditions: Lab Project Number: 951512: 

749-95: I95-22. Unpublished study prepared by Ciba-Geigy Ltd. 36 p. 

44561102 Ward, T.; Magazu, J.; Boeri, R. (1998) Acute Toxicity Of CGA-184927 

to the Daphnid, Daphnid magna: Lab Project Number: 1423-NO: 589-

97. Unpublished study prepared by T.R. Wilbury Labs., Inc. 27 p. 

72-4 Fish Early Life Stage/Aquatic Invertebrate Life Cycle 

Study 

MRID Citation Reference 
Page 42 of 50 

44399119 Hertl, J.; Schreitmuller, J. (1996) Influence of CGA-184927 Technical on 

Survival and Reproduction of Daphnia magna in a Semistatic Test (21 

days) at pH 6.7--7.0: Lab Project Number: 566703: 463-96: 566704. 

Unpublished study prepared by RCC Umweltchemie GmbH & Co. KG. 

45 p. 

44399120 Vial, A.; Bader, U.; de Morsier, A. (1990) Report on the Reproduction 

Test of CGA-184927 Technical to Daphnia (Daphnia magna Straus 

1820): Lab Project Number: 901139: 355-90: 90 11 39. Unpublished 

study prepared by Ciba-Geigy, Ltd. 33 p. 

44399121 Grade, R.; Bader, U.; Gonzalez-Valero, J. (1995) Report on the 

Reproduction Test of CGA-193469 to Daphnia (Daphnia magna Straus 

1820) Under Semi-Static Conditions: Lab Project Number: 951509: 751-

95. Unpublished study prepared by Ciba-Geigy, Ltd. 36 p. 

122-1 Seed Germination/Seedling Emergence and Vegetable 

Vigor 

MRID Citation Reference 

44555002 Schwab, D. (1998) Evaluating the Effects on CGA-184927 on the 

Emergence and Vegetative Vigor of Non-Target Terrestrial Plants: Lab 

Project Number: 44185. Unpublished study prepared by ABC 

Laboratories, Inc. 179 p. 

850.4225 Seedling emergence, Tier II (formerly 123-1) 

MRID Citation Reference 

46012902 Porch, J.; Martin, K.; Krueger, H. (2002) CGA-193469: A Toxicity Test to 

Determine the Effects on Seedling Emergence of Ten Species of Plants: 

Final Report. Project Number: 528/145, 1638/02. Unpublished study 

prepared by Wildlife International, Ltd. 131 p. 

850.4250 Vegetative vigor, Tier II (formerly 123-1) 

MRID Citation Reference 

46012901 Porch, J.; Martin, K.; Krueger, H. (2002) CGA-193469: A Toxicity Test to 

Determine the Effects on Vegetative Vigour of Ten Species of Plants: 

Final Report. Project Number: 528/146, 03/02. Unpublished study 

prepared by Wildlife International, Ltd. 197 p. 
Page 43 of 50 

123-2 Aquatic plant growth 

MRID Citation Reference 

44399161 Grade, R.; Bader, U.; Gonzalez-Valero, J. (1995) Growth Inhibition Test 

of CGA-302371 (Metabolite of CGA-184927) to Green Algae 

(Selenastrum capricornotum) in A Static System: Lab Project Number: 

951510: 750-95: I/95-22. Unpublished study prepared by Ciba-Geigy 

Ltd. 29 p. 

44399162 Grade, R.; Bader, U.; de Morsier, A. (1993) Report on the Growth 

Inhibition Test of CGA-184927 Technical to Green Algae, Scenedesmus 

subspicatus: Lab Project Number: 928202: 514-92: 921536. 

Unpublished study prepared by Ciba-Geigy Ltd. 27 p. 

44399163 Hertl, J.; Schreitmuller, J. (1996) Toxicity of CGA-184927 Technical to 

Scenedesmus subspicatus in an Algal Growth Inhibition Test at pH 7.0: 

Lab Project Number: 566701: 461-96: 566702. Unpublished study 

prepared by RCC Umweltchemie GmbH & Co. KG. 41 p. 

44399164 Grade, R.; Bader, U.; de Morsier, A. (1993) Report on the Growth 

Inhibition Test of CGA-184927 Technical to Blue Algae (Microcystis 

aeruginosa): Lab Project Number: 928201: 516-92: 921535. 

Unpublished study prepared by Ciba-Geigy, Ltd. 27 p. 

44399165 Hoberg, J.; Smith, H.; Gibbons, J. et al. (1993) CGA-184927--Toxicity to 

Duckweed, Lemna gibba: Lab Project Number: 93-6-4832: 614-93: 

1781.0593.6362.410. Unpublished study prepared by Springborn Labs., 

Inc. 73 p. 

44399166 Grade, R.; Bader, U.; de Morsier, A. (1993) Report on the Growth 

Inhibition Test of CGA-184927 Technical to Diatoms (Navicula 

pelliculosa): Lab Project Number: 928203: 515-92: 921537. Unpublished 

study prepared by Ciba-Geigy, Ltd. 27 p. 

44561103 Ward, T.; Magazu, J.; Boeri, R. (1998) Growth And Reproduction 

Toxicity Test With CGA-184927 and the Freshwater Alga, Anabaena 

flos-aquae: Lab Project Number: 1421-NO: 592-97. Unpublished study 

prepared by T.R Wilbury Labs, Inc. 29 p. 

44561104 Ward, T.; Magazu, J.; Boeri, R. (1998) Growth and Reproduction 

Toxicity Test with CGA-184927 and the Freshwater Alga, Selenastrum 

capricornutum: Lab Project Number: 1419-NO: 591-97. Unpublished 

study prepared by T.R. Wilbury Labs, Inc. 29 p. 

141-1 Honey bee acute contact 

MRID Citation Reference 

44399167 Cole, J. (1987) The Acute Contact and Oral Toxicity to Honeybees of 

Compound CGA-184927: Lab Project Number: CBG 447/871222: 202-

87: CBG/447D. Unpublished study prepared by Huntingdon Research 

Centre, Ltd. 17 p. 
Page 44 of 50 

Appendix C: STIR/SIP model outputs 

STIR – ground spray 

Input 

Application and Chemical Information 

Enter Chemical Name 

Clodinafoppropargyl 

Enter Chemical Use wheat 

Is the Application a Spray? (enter y or n) y 

If Spray What Type (enter ground or air) ground 

Enter Chemical Molecular Weight (g/mole) 349.74 

Enter Chemical Vapor Pressure (mmHg) 2.39E-08 

Enter Application Rate (lb a.i./acre) 0.0632 

Toxicity Properties 

Bird 

Enter Lowest Bird Oral LD50 (mg/kg bw) 1455 

Enter Mineau Scaling Factor 1.15 

Enter Tested Bird Weight (kg) 0.178 

Mammal 

Enter Lowest Rat Oral LD50 (mg/kg bw) 1392 

Enter Lowest Rat Inhalation LC50 (mg/L) 2.3 

Duration of Rat Inhalation Study (hrs) 4 

Enter Rat Weight (kg) 0.35 

Output 

Results Avian (0.020 kg ) 

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 4.50E-04 

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 5.65E-05 

Adjusted Inhalation LD50 1.34E+01 

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.22E-06 Exposure not Likely Significant 

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 6.68E-03 

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 4.98E-04 Exposure not Likely Significant 

Results Mammalian (0.015 kg ) 

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 4.50E-04 

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 7.11E-05 

Adjusted Inhalation LD50 1.37E+02 

Ratio of Vapor Dose to Adjusted Inhalation LD50 5.19E-07 Exposure not Likely Significant 

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 8.39E-03 

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 6.13E-05 Exposure not Likely Significant 
Page 45 of 50 

STIR – Aerial spray 

Input 

Application and Chemical Information 

Enter Chemical Name 

Clodinafoppropargyl 

Enter Chemical Use wheat 

Is the Application a Spray? (enter y or n) y 

If Spray What Type (enter ground or air) air 

Enter Chemical Molecular Weight (g/mole) 349.74 

Enter Chemical Vapor Pressure (mmHg) 2.39E-08 

Enter Application Rate (lb a.i./acre) 0.0632 

Toxicity Properties 

Bird 

Enter Lowest Bird Oral LD50 (mg/kg bw) 1455 

Enter Mineau Scaling Factor 1.15 

Enter Tested Bird Weight (kg) 0.178 

Mammal 

Enter Lowest Rat Oral LD50 (mg/kg bw) 1392 

Enter Lowest Rat Inhalation LC50 (mg/L) 2.3 

Duration of Rat Inhalation Study (hrs) 4 

Enter Rat Weight (kg) 0.35 

Output 

Results Avian (0.020 kg ) 

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 4.50E-04 

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 5.65E-05 

Adjusted Inhalation LD50 1.34E+01 

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.22E-06 Exposure not Likely Significant 

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 6.07E-03 

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 4.53E-04 Exposure not Likely Significant 

Results Mammalian (0.015 kg ) 

Maximum Vapor Concentration in Air at Saturation 

(mg/m3) 4.50E-04 

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 7.11E-05 

Adjusted Inhalation LD50 1.37E+02 

Ratio of Vapor Dose to Adjusted Inhalation LD50 5.19E-07 Exposure not Likely Significant 

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 7.63E-03 

Ratio of Droplet Inhalation Dose to Adjusted Inhalation 

LD50 5.57E-05 Exposure not Likely Significant 
Page 46 of 50 

SIP 

Table 1. Inputs 

Parameter Value 

Chemical name clodinafop-propargyl 

Solubility (in water at 25oC; mg/L) 4 

 

Mammalian LD50 (mg/kg-bw) 1392 

Mammalian test species laboratory rat 

Body weight (g) of "other" mammalian 

species 

 

Mammalian NOAEL (mg/kg-bw) 2.5 

Mammalian test species laboratory rat 

Body weight (g) of "other" mammalian 

species 

 

Avian LD50 (mg/kg-bw) 1455 

Avian test species northern bobwhite quail 

Body weight (g) of "other" avian species 

Mineau scaling factor 1.15 

 

Mallard NOAEC (mg/kg-diet) 

Bobwhite quail NOAEC (mg/kg-diet) 500 

Table 2. Mammalian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 0.6880 0.6880 

Adjusted toxicity value (mg/kg-bw) 1070.6715 1.9229 

Ratio of exposure to toxicity 0.0006 0.3578 

Conclusion* 

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

Drinking water exposure 

alone is NOT a potential 

concern for mammals 

Table 3. Avian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 3.2400 3.2400 

Adjusted toxicity value (mg/kg-bw) 1048.2249 53.1492 

Ratio of exposure to acute toxicity 0.0031 0.0610 

Conclusion* 

Drinking water exposure 

alone is NOT a potential 

concern for birds 

Drinking water exposure 

alone is NOT a potential 

concern for birds 

 

*Conclusion is for drinking water exposure alone. This does not combine all routes of exposure. 

Therefore, when aggregated with other routes (i.e., diet, inhalation, dermal), pesticide exposure through 

drinking water may contribute to a total exposure that has potential for effects to non-target animals. 

 
Page 47 of 50 

Appendix D: Chemical Structures 
Page 48 of 50 

 
Page 49 of 50 

Appendix E. Additional Information and Uncertainties with 

Availability Aquatic Toxicity Studies Conducted with 

Degradates of Clodinafop-propargyl 

Acute toxicity classifications indicate that the parent compound is highly toxic to 

freshwater fish and at most slightly to moderately toxic to freshwater invertebrates. The 

degradate CGA-302371 is practically non-toxic to freshwater fish and freshwater 

invertebrates and appears to be less toxic to freshwater organisms (fish, invertebrates, and 

green algae) than the parent. The degradate CGA-193469 is at most moderately toxic to 

freshwater invertebrates. Available data (acute and chronic data on the freshwater 

invertebrate) on the parent, clodinafop-propargyl and the primary degradate, CGA193469, suggest that the relative toxicity is uncertain because the data on the parent is 

either based on a non-definitive values (acute) or is not available (i.e., classified as 

invalid, chronic). A comparison of non-vascular aquatic plant data suggests that the green 

algae (S. subspicatus) is less sensitive to the degradate CGA-302371 than it is to the 

parent compound; however, there are no data available on the primary degradate, CGA193469. Below is a discussion on the available toxicity data conducted with clodinafoppropargyl, as well as any tested degradates: 

1) All acute freshwater invertebrate data on the parent and degradate CGA1934692

 are non-definitive endpoints. For example, the freshwater invertebrate study 

(MRID 44561102) tested the daphnid at levels that far exceed clodinafop-propargyl’s 

limit of solubility yet no mortality was observed, but at levels below water solubility (in 

the MRID 44561102) some mortality was observed. Ultimately, there is variability across 

studies in the freshwater invertebrate data and no clear explanation as to the mortality 

observed at lower concentrations. Furthermore, the freshwater invertebrate study (MRID 

44399116) with the degradate (CGA-193469) is based on testing only a single 

concentration in which the solubility limit is not reported and no solvent is used. 

Although available freshwater invertebrate studies reported non-definitive endpoints that 

are at levels that exceed the surface water EEC for wheat (0.000206 mg/L for the parent; 

USEPA 2000), even when assuming the use of these values as definitive endpoints to 

calculate RQs, the compounds tested (CGA-193469, CGA-302371, and parent), are not 

expected to lead to effects when used on wheat at the currently registered application 

rate. 

2) An available rainbow trout (Oncorhynchus mykiss) study on the degradate 

CGA-302371 yielded a non-definitive endpoint. However, this freshwater fish data 

(MRID 44399108) on the degradate (CGA-302371) had no mortality and good recovery 

of tested compound (mean measured concentrations were 95-104% of nominal) for all 

five tested concentrations, even though the solubility limit of the degradate is not 

 

2

 The only freshwater fish data on the degradate CGA-302371 is also based on a non-definitive endpoint. 

However, the freshwater fish data (MRID 44399108) on the degradate (CGA-302371) had no mortality and 

good recovery of tested compound (mean measured concentrations were 95-104% of nominal) for all five 

tested concentrations. The daphnid study (MRID 44399117) on the same degradate (CGA-302371) is also 

based on a non-definitive endpoint, but there was 20% mortality present at the termination of the study for 

the highest tested concentration. 
Page 50 of 50 

reported. However, a comparison of the freshwater fish studies on the parent compound 

indicates that the bluegill sunfish (Lepomis macrochirus) may be more sensitive to the 

parent (0.24 mg total/L, 95%CI: 0.12-0.26 mg total/L, MRID 44399113) than is the 

rainbow trout (Oncorhynchus mykiss: 0.30 mg a.i./L,95% CI: 0.26-0.34 mg a.i./L, MRID 

44561101; 0.39 mg total/L, 95% CI: 0.22-0.78 mg total/L, MRID 44399114). The 

confidence intervals seemingly overlap (for MRIDs 44399113 and 44561101), but it is 

possible that with centrifugation the bluegill endpoint would have been lower than 

reported. 

3) The only acute bluegill study (MRID 44399113) and one of two trout studies 

(MRID 44399114) did not centrifuge samples prior to analysis even though a precipitate 

was observed. However, measured concentrations were progressively increasing and not 

reflecting sampling undissolved material (so stated for MRID 443991143), a solvent 

(DMF) was used, and the test concentrations were below the aquatic solubility limit of 

the parent (4 mg/L at 25oC). The endpoint values are, at best, based on total test 

compound present, and may not be representative of bioavailable test concentrations (see 

comparison of endpoints above). Although the endpoints did not differ greatly from the 

acceptable trout study, which did not report a precipitate (MRID 44561101), it is possible 

that the actual bioavailable concentrations could yield lower endpoints in the studies 

where precipitate was observed had the samples been centrifuged. 

 

3

 A reclassification of the trout study(MRID 44399114) is not necessary and a new trout study is not 

needed. See data gaps section for freshwater fish discussion.