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problem formulation provides an overview of what is currently known about the environmental 

fate and ecological effects associated with cloransulam-methyl and its degradates. It also 

describes the preliminary ecological risk hypothesis and analysis plan for evaluating and 

characterizing risk to non-target species in support of the registration review of cloransulammethyl. This document also recommends studies that should be included in a generic data call-in 

(DCI) to address uncertainties surrounding the environmental fate and potential ecological 

effects of cloransulam-methyl.
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Problem Formulation for the Environmental Fate, 

Ecological Risk, Endangered Species, and Drinking 

Water Exposure Assessments in Support of the 

Registration Review of Cloransulam-methyl

(chemBlink, 2010)

methyl 3-chloro-2-[[(5-ethoxy-7-fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)

sulfonyl]amino]benzoate

CAS Registry Number: 147150-35-4 

PC Code: 129116

Prepared by:

Elizabeth Bosecker, Biologist

Alicia Korol, Biologist

Reuben Baris, Environmental Scientist

U.S. Environmental Protection Agency

Office of Pesticide Programs

Environmental Fate and Effects Division

Environmental Risk Branch IV

1200 Pennsylvania Ave., NW

Mail Code 7507P

Washington, DC 20460

Reviewed by:

Thomas Steeger, Ph.D, Senior Biologist

Cheryl Sutton, Ph.D., Environmental Scientist

Marietta Echeverria, Branch Chief, ERB IV

December 10, 2010
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Table of Contents

1. Purpose....................................................................................................................................... 5

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

2.1. Nature of Regulatory Action............................................................................................... 5

2.2. Previous Assessments......................................................................................................... 6

2.2.1. Ecological Risk Assessments....................................................................................... 6

2.2.2. Drinking Water Exposure Assessments....................................................................... 6

3. Stressor Source and Distribution ............................................................................................... 6

3.1. Mechanism of Action.......................................................................................................... 6

3.2. Overview of Pesticide Use and Usage ................................................................................ 7

3.3. Environmental Fate and Transport.................................................................................... 11

3.5. Water Quality.................................................................................................................... 14

4. Receptors.................................................................................................................................. 15

4.1. Effects to Aquatic Organisms........................................................................................... 15

4.2. Effects to Terrestrial Organisms....................................................................................... 20

4.3. Incident Databases Review............................................................................................... 23

4.4. Ecosystems Potentially at Risk ......................................................................................... 24

5. Assessment Endpoints ............................................................................................................. 24

6. Conceptual Model.................................................................................................................... 24

6.1. Risk Hypothesis................................................................................................................ 25

6.2. Conceptual Diagram ......................................................................................................... 25

7. Analysis Plan ........................................................................................................................... 27

7.1. Stressors of Concern ......................................................................................................... 28

7.2. Measures of Exposure....................................................................................................... 28

7.3. Measures of Effect ............................................................................................................ 30

7.4. Integration of Exposure and Effects ................................................................................. 31

7.5. Deterministic and Probabilistic Assessment Methods...................................................... 31

7.6. Endangered Species Assessments..................................................................................... 32

7.7. Drinking Water Assessment ............................................................................................. 32

7.8. Preliminary Identification of Data Gaps........................................................................... 33

7.8.1. Environmental Fate.................................................................................................... 33

7.8.2. Effects Data................................................................................................................ 35

8. References................................................................................................................................ 41

APPENDIX A: Registered Uses and Application Rates for Cloransulam-methyl...................... 47

APPENDIX B. Major Environmental Degradates of Cloransulam-methyl. ............................... 52

APPENDIX D. Submitted Ecological Effects Toxicity Data for Cloransulam-methyl .............. 68

APPENDIX E: SIP v.1.0 Inputs and Outputs.............................................................................. 74

APPENDIX F: Data Call-In Tables............................................................................................. 77
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1. Purpose

The purpose of this problem formulation is to provide an understanding of what is known about 

the environmental fate and ecological effects of cloransulam-methyl, considering its currently 

registered use. Cloransulam-methyl is a triazolopyrimidine sulfonanilide herbicide currently 

registered for use on soybeans. There are no residential uses for cloransulam-methyl nor are 

there formulations of cloransulam-methyl classified as “restricted use” pesticides. This

document provides a plan for analyzing data relevant to cloransulam-methyl and for conducting

environmental fate, ecological risk, endangered species, and drinking water exposure 

assessments for its registered use. Additionally, this problem formulation identifies data gaps, 

uncertainties, and potential assumptions used to address those uncertainties relative to 

characterizing the potential ecological risk associated with the registered use of cloransulammethyl on soybean.

2. Problem Formulation

2.1. Nature of Regulatory Action

Under the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), all pesticides distributed 

or sold in the United States generally must be registered by the Environmental Protection 

Agency (Agency). In determining whether a pesticide can be registered in the U.S., the Agency 

evaluates its safety to non-target species based on a wide range of environmental and health 

effects studies. In 1996, FIFRA was amended by the Food Quality Protection Act, and the 

Agency was mandated to implement a new program for the periodic review of pesticides, i.e., 

Registration Review (http://www.epa.gov/oppsrrd1/registration_review/). The Registration 

Review program is intended to ensure that, as the ability to assess risk evolves and as policies 

and practices change, all registered pesticides continue to meet the statutory standard of no 

unreasonable adverse effects to human health and the environment. Changes in science, public 

policy, and pesticide use practices will occur over time. Through the new Registration Review 

program, the Agency periodically reevaluates pesticides to make sure that as change occurs, 

products in the marketplace can be used safely. 

As part of the implementation of the new Registration Review program pursuant to Section 3(g) 

of the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA), the Agency is beginning its 

evaluation of cloransulam-methyl to determine whether it continues to meet the FIFRA standard 

for registration. This problem formulation for the environmental fate, ecological risk, 

endangered species, and drinking water assessment chapter in support of the registration review 

of cloransulam-methyl will be posted in the initial docket which will open the public phase of the 

review process.
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2.2. Previous Assessments

2.2.1. Ecological Risk Assessments

Cloransulam-methyl was first registered in 1997 by DowElanco. According to the chemical's 

initial assessment (D223558, D223605; USEPA, 1997), risk to non-target terrestrial plants 

resulting from cloransulam-methyl use was identified based on Risk Quotients (RQs) ranging 

from <1 to 12. In contrast, the Agency‟s Level of Concern (LOC) was not exceeded for nontarget aquatic plants, nor Federally listed threatened and endangered (listed) or non-listed 

terrestrial or aquatic animals. Label precautions for non-target insects were deemed unnecessary 

because cloransulam-methyl was categorized as practically non-toxic to young adult honey bees 

(USEPA, 1997) on an acute contact exposure basis. Further, cloransulam-methyl and its 

similarly structured transformation products were determined to exhibit characteristics similar to 

those pesticides that are known to leach to ground water. Thus a prospective ground water study 

was requested as a condition of registration.

After reviewing the previous risk assessment, modifications to the previous risk analyses are 

expected. These changes are due to an evolution of Agency policy since cloransulam-methyl 

was first registered (e.g., evaluating drinking water exposure to birds and mammals). While nontarget terrestrial and aquatic plants were previously assessed, an assessment on listed species in 

these taxa was not performed. Further, environmental fate and ecological toxicity data were reevaluated as part of the Registration Review process and certain studies that previously met 

guideline standards or registration requirements may no longer meet current guideline standards 

(e.g., terrestrial plant toxicity studies). 

2.2.2. Drinking Water Exposure Assessments

A full drinking water assessment has not been conducted for cloransulam-methyl. While a 

limited-scope water resources assessment was completed as part of the new chemical registration 

in 1997 (DP Barcodes D223558 and D223560), that assessment is not consistent with the current 

standards used by EFED to assess drinking water exposure. A full drinking water exposure 

assessment using up-to-date models and data will be completed during the registration review 

process. At that time, the Health Effects Division (HED) will be consulted in order to determine 

which, if any, of cloransulam-methyl‟s degradates are residues of toxicological concern and 

should be included in the drinking water exposure assessment in support of the human health 

dietary risk assessment. Many degradates detected in the fate studies are considered major 

degradates due to their formation at concentrations >10% of the applied parent (identified in 

Section 3.4).

3. Stressor Source and Distribution

3.1. Mechanism of Action
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Cloransulam-methyl is an Acetohydroxyacid Synthetase (AHAS) inhibitor also known as an

Acetolactate Synthase inhibitor (ALS inhibitor) in the triazolopyrimidine herbicide family 

(HRAC, 2009). Acetolactate Synthase is responsible for the production of three essential amino 

acids. An inhibition of this enzyme causes stunting and delayed growth that can ultimately lead 

to plant death (UM Extension, 2009). Cloransulam-methyl is a systemic herbicide that moves 

through the xylem and phloem (as opposed to certain ALS inhibitors that only move through 

phloem) to areas of new growth, and it is taken up by the plant through roots and foliage (UM 

Extension, 2009). 

3.2. Overview of Pesticide Use and Usage

Cloransulam-methyl is currently registered for use as a pre- and post-emergent herbicide in 

soybean production. Eight end-use products containing cloransulam-methyl are currently 

registered for use in the United States (Table 3.2). End-use products are formulated as 

suspension concentrates (SC), water soluble packets (WSP), and wettable powders (WP). Five 

of these end-use products are co-formulated or co-packaged with one of three other active 

ingredients; three with sulfentrazone (CAS number 122836-35-5; GAUNTLET®70 DF 

HERBICIDE, GAUNTLET®70 WP HERBICIDE, and AUTHORITY® DF Herbicide); one with 

flumetsulam (CAS number 98967-40-9; FRONTROW®); and one with flumioxazin (CAS 

number 103361-09-7; GANGSTER® HERBICIDE WSP). 

Table 3.2. Currently Registered Cloransulam-methyl End-Use Products.

FORMULATION EPA REG. 

NO.

% ACTIVE METHODS OF 

APPLICATION

USE RESTRICTIONS

RIVERDALE®565 

SELECTIVE 

HERBICIDE

SC

228-380 84 Ground - Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.

- Do not apply through an irrigation system

- Avoid direct or indirect contact with non-target 

plants.

-Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites.

-Aerial application is prohibited.

-If used in OH, MN, MI, WI, IA, NE, KS,OK, MO 

(excluding bootheel), IL and IN (north of 

Interstate 64), SD, ND, PA, and NY, if soil OM is 

3% or less, use 0.6 oz/acre. If soil OM is greater 

than 3% use 0.75 oz/acre. South of Interstate 64 

in IL and IN at all OM levels use 0.75 oz/acre. 

GAUNTLET®

WSP

279-3231 42 Ground - Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.

- Do not apply through an irrigation system

-Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites.

GAUNTLET®70 

DF HERBICIDE

279-3246 7.9 Ground - Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.
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FORMULATION EPA REG. 

NO.

% ACTIVE METHODS OF 

APPLICATION

USE RESTRICTIONS

WP -Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites.

GAUNTLET®70 

WP HERBICIDE

WP

279-3247 7.9 Ground - Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.

- Do not apply through an irrigation system

-Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites.

GANGSTER®

HERBICIDE

WSP

59639-131 84 Ground

Aerial (Except 

New York)

- Do not apply through an irrigation system

-Do not graze treated fields or feed treated forage 

or hay to livestock

-Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites.

-If applying by air, observe drift management 

restrictions and precautions issued under Aerial 

Application

 -Do not apply during low-level inversion 

 conditions when winds are gusty, etc.

 -Do not apply within 40 ft. of non-target plants 

 or crops

 -Do not apply within 100 ft. of emerged cotton 

 crops

 -Do not apply within 40ft of streams, 

 wetlands, marshes, ponds, lakes, and 

 reservoirs

 -Do not apply by air in the state of New York

CLORANSULAMMETHYL®

TECHNICAL

62719-274 97.5 N/A 

(Manufacturing 

Use)

-Do not discharge effluent containing this product 

into lakes, streams, ponds, estuaries, oceans, or 

other water unless with the requirements of the 

NPDES permit and the primary authority has been 

notified. 

-Do not discharge effluent containing this product 

into sewer systems without previously notifying 

the local sewage treatment plant authority

FIRSTRATE®

WP

62719-275 84 Ground

Aerial (Except 

New York)

- Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.

- Do not apply through an irrigation system

-Do not apply under conditions which favor runoff 

or wind erosion, or when conditions favor drift to 

non-target sites

-If used in DE, CT, IA, KS, MD, ME, MI, MN, 

MO (excluding the bootheel), ND, NE, NH, OH, 

OK, SD, VT, WI, PA, NY, and areas north of 

Interstate 64 in the states of IL, IN, KY, WV, and 

VA is soil OM is 3.0% or less use 0.6 oz/acre. If 

soil OM is greater than 3.0% use 0.75 oz/acre. All 

areas south of the above mentioned geographic 

area at all OM levels use 0.75 oz/acre.

FRONTROW® 62719-299 84 Ground

Aerial (Except in 

-Do not apply directly to water, areas where 

surface water is present, or intertidal areas below 
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FORMULATION EPA REG. 

NO.

% ACTIVE METHODS OF 

APPLICATION

USE RESTRICTIONS

WSP

New York) the mean high water mark.

- Do not mix, load, rinse, or wash equipment or 

containers within 50 feet of any wells or other 

bodies of water.

- Do not apply through an irrigation system

-Do not apply more than 0.84 oz per acre per crop 

growing season.

-Do not exceed 0.07 lb cumulative application of 

the active ingredient flumetsulam.

-Do not exceed 0.055 lb per year of the active 

ingredient cloransulam-methyl 

-Do not graze treated fields or feed treated forage 

or hay to livestock

-If applying by air, observe drift management 

restrictions and precautions issued under Aerial 

Application

 -Do not apply during low-level inversion 

 conditions when winds are gusty, etc.

 -Do not apply within 40 ft. of non-target plants 

 or crops

 -Do not apply within 100 ft. of emerged cotton 

 crops

 -Do not apply within 40ft of streams, 

 wetlands, marshes, ponds, lakes, and 

 reservoirs

 -Do not apply by air in the state of New York

-Avoid all direct and indirect contact with nontarget plants

-Do not harvest soybeans for 70 days after 

application of Frontrow®.

The maximum seasonal application rate for cloransulam-methyl on soybeans is 0.055 pounds of 

active ingredient per acre (lbs a.i./A), while the maximum single application rate is 0.040 lbs 

a.i./A. The risk assessment will assess one cropping season per year of soybeans, an annual rate 

of 0.055 lbs a.i./A, which reflects the majority of cloransulam-methyl use in the United States 

(USDA, 1997). As can be seen in APPENDIX A, the labels permit slightly higher application 

rates for soils with greater than 3% soil organic matter. APPENDIX A provides a complete list 

of registered products and their corresponding single and seasonal maximum application rates. 

According to the United States Geological Survey‟s (USGS; 

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=02&map=m9103) national 

pesticide usage data, an annual average of 82,155 lbs of cloransulam-methyl, based on data for 

the years 1999 to 2004, were applied nationally to soybeans in the United States. The highest 

use areas are in the Midwest and along the Mississippi River watershed (Figure 3.1). Additional 

data based on a Screening Level Usage Analysis (SLUA) conducted by the Agency (USEPA,

2010), using data from 1998 to 2008, reported the average annual cloransulam-methyl use was 

44,000 lb a.i./year. This yearly average is almost half of that reported by the USGS, but the 

SLUA data covers 11 years of usage rather than the 6 years covered by the USGS. The SLUA 

data indicate that cloransulam-methyl usage increased from 1998-2001 and then almost steadily 
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decreased from 2002 to 2007, where 4 of the 5 highest annual average usages occurred in the 

years 1999 – 2002 (Figure 3.2). 

FIGURE 3.1. USGS Estimated, Annual, National, Agricultural Cloransulam-methyl Usage 

from 1999-2004 (USGS 2010; 

http://water.usgs.gov/nawqa/pnsp/usage/maps/show_map.php?year=02&map=m9103).1

 

1 The pesticide use maps available from National Pesticide Synthesis site show the average annual pesticide use 

intensity expressed as average weight (in pounds) of a pesticide applied to each square mile of agricultural land in a 

county. The area of the map is based on state-level estimates of pesticide use rates for individual crops that were 

compiled by the CropLife Foundation, Crop Protection Research Institute based on information collected during 

1999 through 2004 and on 2002 Census of Agriculture county crop acreage. The maps do not represent a specific 

year, but rather show typical use patterns over the five year period 1999 through 2004.
-11 of 85-

FIGURE 3.2. Screening Level Usage Analysis (SLUA) of National, Annual, Agricultural 

Cloransulam-methyl Usage from 1998-2008 (USEPA, 2010)

3.3. Environmental Fate and Transport

Laboratory and field data indicate that cloransulam-methyl (methyl 3-chloro-2-[[(5-ethoxy-7-

fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-yl)sulfonyl]amino]benzoate) is highly mobile in the 

environment (mean Freundlich adsorption constant (Kf) of 0.84 mL/g; MRIDs 43003435, 

43216602) and is essentially non-volatile (vapor pressure of 3.0 x 10-16 torr; MRID 43668933). 

The major routes of dissipation appear to be biotic metabolism, abiotic photolysis in water and 

soil, and leaching. Hydrolysis may be an important mode of dissipation in alkaline environments 

(pH 9). However, there is uncertainty about the fate of cloransulam-methyl in aquatic 

environments since acceptable aerobic aquatic metabolism data have not been submitted. 

The initial transformation of cloransulam-methyl involves modifications of functional groups 

while the structural “backbone” of the chemical remains intact. The three transformation 

products that retain a similar structure to the parent (cloransulam, 5-hydroxy-chloransulam, and 

5-hydroxy-cloransulam-methyl) appear to be mobile, and more persistent than the parent. In 

studies done on Green Alga (Psuedokirchneriella subcapitata, reported as Selenastrum 

capricornutum Printz), the demethylated cloransulam is the only degradate that is shown to have 

similar toxicity to parent cloransulam-methyl based on aquatic nonvascular plant toxicity data 

(MRIDs 44744514 and 43668917). Later degradation involves cleavage of the sulfonamide 

bridge or a break in the triazolopyrimidine ring and requires more energy (from photolysis) or 

special conditions (alkaline hydrolysis or anaerobic metabolism). Laboratory studies reported 

cloransulam-methyl had a transformation half-life of 9 to 30 days in aerobic soil under laboratory 

conditions. In an anaerobic aquatic water/sediment system, cloransulam-methyl degraded with a 

total system half-life of 16 days. Acceptable guideline data showing the fate of the compound in 

an aerobic aquatic water/sediment system are not available. In field studies, half of the parent 

Cloransulam-methyl

0

80,000

1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008

Year

Pounds AI
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dissipated from the surface in less than 6 days (DT50) largely attributed to metabolism and 

photolysis at the surface in the warm, moist soil exposed to sunlight at both field sites. However, 

parent cloransulam-methyl and structurally similar transformation products were detected at a 

maximum depth of 45 cm (27 DAT), and at 30 cm (155 DAT) indicating that cloransulammethyl and its structurally similar transformation products may persist longer in the subsurface 

soil layers relative to surface layers.

Microbial transformation and abiotic soil photolysis occur in the surface layer of the soil, but 

these processes may not be major factors if the chemical leaches to the subsurface, where 

hydrolysis or other slower degradation processes may dominate. So, cloransulam-methyl and its 

structurally-similar transformation products may be more persistent when leached into the 

subsurface. However, there are several uncertainties about the fate of cloransulam-methyl, 

namely the biotic degradation in anaerobic environments (e.g., subsurface below 1 meter) due to 

lack of anaerobic soil metabolism data. Further, the potential risk of ground water contamination 

resulting from applications of cloransulam-methyl is uncertain due to the potential persistence in 

the subsurface layers where metabolic activity is low. In an attempt to address this uncertainty, a 

prospective ground water (PGW) study conducted at three U.S. sites was submitted as a 

condition of the registration of the compound, and is currently under review.

Additional data submitted in support of the PGW studies has been reviewed and classified as 

supplemental. Two sites, La Porte, Indiana, and Janesville, Iowa, used for a cloransulam-methyl 

prospective groundwater (PGW) study had been previously used for flumetsulam (La Porte, IN) 

and flufanacet (Janesville, IA) PGW studies. In a study (MRID 44809201) conducted to 

investigate whether enhanced degradation of cloransulam-methyl might occur in field soils 

previously treated with flumetsulam or flufanacet, it was found that there was no enhanced 

degradation of cloransulam-methyl due to the previous treatment with the other pesticides.

Table 3.4 summarizes the general physical, chemical, and fate and transport properties of 

cloransulam-methyl.

Table 3.4. General Chemical Properties and Environmental Fate Properties of 

Cloransulam-methyl.

Parameter Value Reference Comments

Selected Physical/Chemical Parameters

Molecular mass 429.82 g/mol MRID 43668933

Vapor pressure (20°C) 3.0 x 10-16 torr MRID 43668933

Water solubility (20°C) 3 mg/L (pH 5)

180 mg/L (pH 7)

3400 mg/L (pH 8.5)

MRID 43668933

Henry‟s law constant (20°C, pH 7) 9.43 x 10-19 Calculated HLC = (VAPR÷760) ÷ 

(SOL÷MWT)

Octanol-water partition coefficient 

(LogKOW) (20°C)

pH 5 = 1.12

pH 7 = -0.365

pH 8.5 = -1.24

MRID 43668933

Persistence
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Parameter Value Reference Comments

Hydrolysis

pH 5: stable

pH 7: stable

pH 9: 3 days

MRID 43003432 pH 7 half-life was 

extrapolated beyond the 

study duration (118-231 

days)

Aqueous Photolysis (t 1⁄2 ) 

0.015 days (22 minutes) MRID 43715402 Corrected environmental 

half-life (40oN)

Soil Photolysis (t 1⁄2 )

30-70 days MRID 43760001 There are significant 

differences in the halflives of the two radiolabeled studies.

Aerobic Soil Metabolism, parent only

(t 1⁄2 )

Biphasic Kinetic Model:

13 days (loam) 

 Observed DT50=22 days

 Observed DT90=225days

9 days (loamy sand)

 Observed DT50=14 days

 Observed DT90=150 days

MRID 43003433 Cloransulam-methyl does 

not appear to fit the 1st

order model, exhibits 

biphasic degradation.

An additional study is 

currently under review 

(MRID 44809201). 15, 15, 15, 18, 22, 21, 21, 

13, 30, 15, 17, 17, 18, 19, 

20, 19 days

MRID 43216602, 

43003435†

(ancillary data)

Aerobic soil metabolism Half-lives not useful other 

than for comparison to data 

for previously treated soils.

MRID 

44809201

Supplemental study with 

some deficiencies

precluding use of t1⁄2‟s for 

assessment purposes. 

Anaerobic Soil Metabolism

No data --

Anaerobic Aquatic Metabolism (t 1⁄2 )

16 days MRID 43715403 Supplemental study. The 

pH of the system was not 

reported.

Aerobic Aquatic Metabolism

No data --

Mobility

Freundlich Kf (mL/g) 0.82, 0.40, 0.49, 1.45, 0.32, 

0.21, 4.89, 0.29, 1.06, 0.45, 

0.97, 0.29, 0.33, 0.19, 1.06, 

0.25

MRID 43003435, 

43216602

There was no correlation 

between Kf and % organic 

carbon. Mean Kf of 0.84 

mL/g.

Organic Carbon Partitioning Coefficient 

Koc (mL/g oc)

67, 16, 158, 242, 16, 20, 

157, 60, 54, 18, 262, 28, 12, 

34, 51, 27

MRID 43003435, 

43216602

Coefficient of variance is 

less for Kfthan Koc

Field Dissipation
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Parameter Value Reference Comments

Terrestrial Field Dissipation (t 1⁄2 )

(top 15 cm of soil)

3.5 days (Indiana) 

5.0 days (Mississippi)

MRID 43716002 Dissipation half-lives are 

based on a non-linear 2-

compartment model. 

DT90‟s at both sites were 

less than 45 days. Warm 

sunny weather and moist 

soil favored photolysis 

and metabolism as 

dissipation routes. 

In Review MRID 44231501

† MRID 43216602 an adsorption/desorption study provides ancillary data for aerobic degradation of cloransulam-methyl which will be used as 

additional aerobic soil metabolism degradation half-lives.

3.4. Degradates of Concern

Major degradates are compounds that form at greater than 10% of the applied in at least one fate 

study, or are known to be toxicologically significant. There were nine major degradates reported 

in the fate studies. These include the structurally similar transformation products cloransulam

(37-38% at 28 days), 5-hydroxy-cloransulam-methyl (17% at 14 days) and 5-hydroxycloransulam (11-21% after 120 days) which were observed in the aerobic and anaerobic 

metabolism studies. Other degradates such as cloransulam-methyl fluorethenyl (49-54% at 365 

days) were found in anaerobic conditions. Cloransulam-methyl fluorethenyl appears to be 

persistent under anaerobic conditions (concentrations were increasing at the termination of the 

study 365 DAT). Sulfonic acid (TSPA) was the major photolytic degradate in the soil photolysis 

study (peak concentration of 22% at the end of the study). Sulfinic acid was detected in the 

aqueous photolysis study (23% at the end of the study). Cloransulam-methyl imidate (max. of 

29%) and cloransulam-methyl acetic acid (max. of 54%) were associated with the hydrolysis of 

cloransulam-methyl. Appendix B lists all the major degradates, chemical structures, chemical 

names, and which studies are associated with the formation of each degradate.

3.5. Water Quality

Cloransulam-methyl is not identified as a cause of impairment for any water bodies under section 

303(d) of the Clean Water Act2. In addition, no Total Maximum Daily Loads (TMDL) have been 

developed for cloransulam-methyl3and there are no aquatic life criteria for cloransulam-methyl4. 

More information on impaired water bodies and TMDLs can be found at 

http://www.epa.gov/owow/tmdl/.

 

2

based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=885, accessed July 

21, 2010

3

based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation.tmdl_pollutant_detail?p_pollutant_group_id=885&p_pollutant_

group_name=PESTICIDES, accessed Jan. 26, 2010

4

based on information provided at http://www.epa.gov/waterscience/criteria/aqlife/index.html
-15 of 85-

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.

No monitoring data were available for cloransulam-methyl. Neither the USGS‟s National Water 

Quality Assessment (NAWQA) program nor the California Department of Pesticide Regulation 

monitoring programs included cloransulam-methyl as an analyte.

4. Receptors

Consistent with the process described in the Overview Document (USEPA, 2004), the risk 

assessment for cloransulam-methyl relies on a surrogate species approach. Toxicological data 

generated from surrogate test species, which are intended to be representative of broad 

taxonomic groups, are used to extrapolate the potential effects on a variety of species (receptors) 

included under these taxonomic groupings.

Acute and chronic toxicity data from studies submitted by pesticide registrants along with the 

available open literature are used to evaluate the potential direct and indirect effects of 

cloransulam-methyl to aquatic and terrestrial receptors. This includes toxicity on the technical 

grade active ingredient, degradates, and when available, formulated products (e.g., “Six-Pack” 

studies). The open literature studies are identified through EPA‟s ECOTOXicology (ECOTOX) 

database, which employs a literature search engine for locating chemical toxicity data for aquatic 

life, terrestrial plants, and wildlife. The evaluation of both sources of data may also provide 

insight into the direct and indirect effects of cloransulam-methyl on biotic communities from loss 

of species that are sensitive to the chemical and from changes in structure and functional 

characteristics of the affected communities. Open literature studies from an ECOTOX run 

conducted in April of 2010 for cloransulam-methyl have not been formally reviewed as part of 

this Problem Formulation. A preliminary screen of the data reveals an acceptable study on 

terrestrial plants, mentioned in Section 4.2. References to all studies, both acceptable and 

unacceptable for EFED‟s use, are presented in Appendix C. Data from these studies and data 

from an up-dated ECOTOX run for cloransulam-methyl will be evaluated for possible 

quantitative and/or qualitative inclusion in the risk assessment in support of Registration Review.

A summary of the most sensitive data representing non-target organisms exposed to 

cloransulam-methyl in aquatic and terrestrial habitats is provided in Section 4.1. A summary of 

ecological incidents associated with cloransulam-methyl and a description of ecosystems 

potentially at risk are provided in Section 4.2.

4.1. Effects to Aquatic Organisms

Effects data are available on aquatic animals and plants for cloransulam-methyl, as well as 
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aquatic plants for the degradates 5-hydroxy-cloransulam-methyl, 5-hydroxy-cloransulam, and 

cloransulam. Based on the available data, cloransulam-methyl is categorized as slightly toxic on 

an acute exposure basis to freshwater fish and practically non-toxic on an acute basis to

estuarine/marine fish and invertebrates. There are no acute toxicity data for freshwater 

invertebrates. Additionally, because chronic data on aquatic organisms were not required at the 

time cloransulam-methyl was first registered, no chronic toxicity data exists for freshwater and 

estuarine/marine fish and invertebrates. The most sensitive species for each taxa from submitted 

aquatic animal toxicity studies are presented in Table 4.1. A summary of all submitted

ecotoxicity data for cloransulam-methyl and degradates is provided in Appendix D. 

Table 4.1. Summary of the Most Sensitive Species by Taxon from Submitted Aquatic

Animal Toxicity Studies for Cloransulam-methyl. 

TAXON SPECIES ENDPOINT CHEMICAL/

FORMULATION MRID

STUDY 

CLASSIFICATION

Freshwater 

Fish (Acute)

Rainbow Trout

(Oncorhynchu

s mykiss)

96-hr LC50

>86 mg a.i./L

Cloransulammethyl (97.3%)430034

-10 Acceptable

Estuarine/

Marine Fish 

(Acute)

Inland 

Silverside 

(Menidia 

beryllina)

96-hr LC50

>121 mg a.i./L

Cloransulammethyl (97.4%)437189

-01 Acceptable

Estuarine/

Marine 

Invertebrates 

(Acute)

Eastern Oyster 

(Crassostrea 

virginica)

96-hr LC50 

>111 mg a.i./L

Cloransulammethyl (97.4%)437189

-02 Acceptable

Freshwater 

Fish 

(Chronic)

-- -- -- -- --

Freshwater 

Invertebrates

(Acute & 

Chronic)

-- -- -- -- --

Estuarine/

Marine Fish

(Chronic)

-- -- -- -- --

Estuarine/

Marine 

Invertebrates

(Chronic)

-- -- -- -- --

Data from acceptable acute 96-hour freshwater fish studies were submitted for rainbow trout, 

Oncorhynchus mykiss, (MRID 430034-10) and bluegill sunfish, Lepomis macrochirus (MRID 

430034-11). No treatment-related mortalities nor sublethal effects were observed for either 

study; the resulting LC50 values were >89 mg a.i./L for the rainbow trout (most sensitive 

freshwater fish species tested) and >154 mg a.i./L for the bluegill sunfish, based on mean 

measured concentrations of filtered samples. Both studies were conducted as limit 

concentrations of nominal 300 mg a.i./L, but due to the limit of solubility, filtered samples of 

average concentrations over the 96-hr study period were 89 mg a.i./L and 154 mg a.i./L for the 
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rainbow trout and bluegill study, respectively. Based on this data, cloransulam-methyl‟s toxicity 

to freshwater fish is limited by solubility. Data are available for one estuarine/marine fish, the 

inland silverside, Menidia beryllina (MRID 437189-01), resulting in a 96-hr LC50 >121 mg 

a.i./L. The solubility of cloransulam-methyl was determined to be 232 mg/L for the test, and as 

such, insoluble material was not noted in the test media (pH ranged from 7.7 – 8.1). Nominal 

and mean-measured concentrations were 125 mg a.i./L and 121 mg a.i./L, respectively. No 

mortality or signs of toxicity were reported for the duration of the study. 

Two acceptable toxicity studies were submitted on aquatic invertebrates, an acute toxicity study 

to the grass shrimp, Palaemonetes pugio, (MRID 437189-03) and an acute toxicity to the Eastern 

oyster, Crassostrea virginica, (MRID 437189-02). No mortality or sublethal effects from 

cloransulam-methyl exposure were reported for the grass shrimp; the 96-hr LC50 was >121 mg 

a.i./L. In contrast, effects on mean shell deposition to the Eastern oyster were reported at the 

limit concentration (111 mg a.i./L) tested. Mean shell deposition was decreased 18% compared 

to the negative control, and no additional adverse effects were noted. The 96-hr EC50 for Eastern 

oyster was >111 mg a.i./L (most sensitive estuarine/marine invertebrate acute toxicity endpoint) 

and the 96-hr NOAEC was < 111 mg a.i./L based on mean shell deposition. No insoluble

material was noted in either the grass shrimp or eastern oyster study throughout the duration of 

the test. An acute study for freshwater invertebrates, looking at the waterflea (Daphnia magna), 

was submitted but classified invalid (MRID 43003412). No chronic study on aquatic 

invertebrates has been submitted. 

The most sensitive species for both vascular and nonvascular aquatic plants for cloransulammethyl and degradates from submitted toxicity studies are presented in Table 4.2. 

Table 4.2. Summary of the Most Sensitive Endpoints from Submitted Aquatic Plant

Toxicity Studies for Cloransulam-methyl and Degradates. 

TAXON ENDPOINT CHEMICAL/

FORMULATION MRID STUDYCLASSIFICATION

Aquatic Nonvascular Plants

Green Alga 

(Psuedokirchneriella 

subcapitata,formerly 

Selenastrum 

capricornutum)

96-hr EC50 = 0.003 

mg a.i./L

Slope: 1.04 0.159

NOAEC = 0.00094 

mg a.i./L

(algal cell density)

Cloransulam-methyl 

(Firstrate®; 82.2%) 447445-17 Acceptable

Cyanobacteria 

(Anabaena flosaquae)

120-hr EC50 = >29.9 

mg a.i./L

NOAEC = 29.9 mg 

a.i./L

(algal cell density)

5-hydroxycloransulam-methyl 

(>95%)

447445-01 Supplemental

Freshwater Diatom 

(Navicula 

pelliculosa)

120-hr EC50 = >10.7 

mg a.i./L

NOAEC = 5.64 mg 

a.i./L

(algal cell density)

5-hydroxycloransulam (>96%) 447445-07 Supplemental
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Green Alga 

(P. 

subcapitata,formerly

S. capricornutum )

96-hr EC50 = 0.0074 

mg a.i./L

Slope: 1.06 0.145

EC05 = 0.0021 mg 

a.i./L

(algal cell density)

Cloransulam (>96%) 447445-14; 

436689-17 Acceptable

Aquatic Vascular Plants

Duckweed

(L. gibba)

14-day EC50 = 110 

mg a.i./L (frond 

number)

Slope: 6.44 0.159

NOAEC = 58.3 mg 

a.i./L (frond number 

& growth rate)

5-hydroxycloransulam-methyl 

(>95%)

447445-05 Supplemental

Duckweed

(L. gibba)

14-day EC50 = ≥ 100 

mg a.i./L (frond 

number)

NOAEC = 53.6 mg 

a.i./L

5-hydroxycloransulam (>97%) 447445-10 Acceptable

Duckweed

(L. gibba)

14-day EC50 = 0.130 

mg a.i./L (frond 

number)

Slope: 4.51 0.439

NOAEC = 0.0611mg 

a.i./L

Cloransulam (>96%) 447445-15 Acceptable

An acceptable Tier II toxicity study on the green alga, Psuedokirchneriella subcapitata, (MRID 

447445-17) was submitted for cloransulam-methyl using the formulated product Firstrate®

(82.2%); the resulting 96-hr EC50 was 0.003 mg a.i./L with a corresponding NOAEC of 0.00094 

mg a.i./L. A study conducted on the toxicity to nonvascular plants with the technical grade 

active ingredient was not submitted. A Tier II study (MRID 436689-16) conducted on the 

aquatic vascular plant duckweed, Lemna gibba, with the technical grade active ingredient is 

classified as invalid and cannot be used in an assessment.

Tier II algal toxicity studies on aquatic plants have been submitted for the degradates 5-hydroxycloransulam-methyl, 5-hydroxy-cloransulam, and cloransulam. For 5-hydroxy-cloransulammethyl, three scientifically valid Tier II toxicity studies were submitted, a study on the green alga 

P. subcapitata (MRID 447445-04), the cyanobacteria Anabaena flos-aquae (MRID 447445-01), 

and the saltwater diatom Skeletonema costatum (MRID 447445-03). A second toxicity study is 

available with P. subcapitata (MRID 437600-04) for 5-hydroxy-cloansulam-methyl; however, it 

was conducted as a preliminary experiment, where numerous guideline deviations and data 

omissions were apparent, and the study is considered supplemental information for qualitative 

use only. A submitted study for 5-hydroxy-cloransulam-methyl on the freshwater diatom 

Navicula pelliculosa (MRID 447445-02) was determined to be scientifically unsound and is 

classified invalid. The EC50 and NOAEC values from the acceptable studies are presented in 

Appendix D. Overall, the acceptable studies demonstrate that 5-hydroxy-cloransulam-methyl is 

less toxic to fresh- and saltwater algae than is cloransulam-methyl. EC50 values for 5-hydroxycloransulam-methyl based on algal cell density range from >26.3 mg a.i./L to >93.3 mg a.i./L 

(for both 96-hr and 120-hr studies), much higher than the most sensitive 96-hr EC50 for 

cloransulam-methyl (0.003 mg a.i./L). For two of these studies, the green alga and 
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cyanobacteria, a major change in pH occurred at the two highest test concentrations (nominal 

50.0 and 100 mg a.i./L). Between both studies, pH ranged from 3.7-5.9 at the two highest test 

concentrations. The drop in pH did not appear to affect the solubility of 5-hydroxy-cloransulammethyl.

Four Tier II algal studies were submitted for 5-hydroxy-cloransulam on P. subcapitata (MRID 

447445-09), A. flos-aquae (MRID 447445-06), S. costatum (MRID 447445-08), and N. 

pelliculosa (MRID 447445-07). A second study was submitted for P. subcapitata (MRID 

437600-04), but it was conducted as a preliminary experiment, where numerous guideline 

deviations and data omissions were apparent, and the study is considered supplemental 

information for qualitative use only. The EC50 and NOAEC values, if available, are presented 

for these studies in Appendix D. Overall, the acceptable studies demonstrate that 5-hydroxycloransulam is less toxic to fresh- and saltwater algae than is cloransulam-methyl. The 96-hr and 

120-hr EC50 values for 5-hydroxy-cloransulam-methyl based on alga cell density ranged from 

>10.7 mg a.i./L to >103 mg a.i./L, higher than the most sensitive 96-hr EC50 for cloransulammethyl (0.003 mg a.i./L). The 5-hydroxy-cloransulam degradate demonstrated the same effects 

on pH that 5-hydroxy-cloransulam-methyl exhibited. Test media for the higher concentrations 

(nominal 25.0, 50.0, 100 mg a.i./L) tested for the freshwater green alga, freshwater diatom, and 

freshwater cyanobacteria, had pH values in the range of 3.3 to 5.0. The drop in pH did not 

appear to affect the solubility of 5-hydroxy-cloransulam for the duration of the tests.

Four Tier II algal studies submitted for cloransulam on P. subcapitata (MRID 447445-14), A. 

flos-aquae (MRID 447445-11), S. costatum (MRID 447445-13), and N. pelliculosa (MRID 

447445-12). A summary of the EC50 and NOAEC or EC05 values are presented for these studies 

in Appendix D. Based on a comparison of toxicity to P. subcapitata, cloransulam is roughly as 

toxic to nonvascular plants as cloransulam-methyl: the 96-hr EC50 based on alga cell density for 

cloransulam and cloransulam-methyl is 0.0074 mg a.i./L and 0.003 mg a.i./L, respectively (see 

Table 4.3). The toxicity of cloransulam to other algae is magnitudes less than the toxicity to P. 

subcapitata, with 120-hr EC50 values ranging from >3.65 mg a.i./L to >90.8 mg a.i./L. 

Cloransulam appeared to affect pH at the highest concentration tested (nominal 100 mg a.i./L) 

with the freshwater diatom (N. pelliculosa); no effect on solubility was noted. 

Toxicity studies on the aquatic vascular plant, L. gibba, were also submitted for the degradates 5-

hydroxy-cloransulam-methyl (MRID 447445-05), 5-hydroxy-cloransulam (MRID 447445-10), 

and cloransulam (MRID 447445-15). The EC50 and NOAEC are presented for these studies in 

Appendix D. Overall, cloransulam is orders of magnitude more toxic to L. gibba based on algal 

cell density than the other two degradates: The 14-d EC50 for cloransulam, 5-hydroxycloransulam-methyl, and 5-hydroxy-cloransulam is 0.130, 110, ≥100 mg a.i./L, respectively (see 

Table 4.3). No effects on pH were observed for these studies. A study on L. gibba submitted

for cloransulam-methyl was classified as invalid because it was scientifically unsound. 

Table 4.3 presents a comparison of toxicity to P. subcapitata and L. gibba between cloransulammethyl and degradates. The data indicate that cloransulam-methyl and cloransulam are equally 

toxic to P. subcapitata, while 5-hydroxy-clornasulam-methyl and 5-hydroxy-cloransulam are 

order of magnitude less toxic. 
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Table 4.3: Most Sensitive Endpoints for Aquatic Plant Toxicity Studies using P. 

subcapitata and L.gibba for Cloransulam-methyl and Degradates 

CHEMICAL SPECIES ENDPOINT (mg 

a.i./L) MRID

STUDY 

CLASSIFICATION

Aquatic Nonvascular Plants

cloransulam-methyl 

(First-rate; 82.2%)

Green Alga 

(P. subcapitata,

formerly S. 

capricornutum

Printz)

96-hr EC50 = 0.003 

NOAEC = 0.00094 

(algal cell density)

447445-17 Acceptable

cloransulam (>96%)

96-hr EC50 = 0.0074 

EC05 =0.0021

(algal cell density)

447445-14; 

436689-17 Acceptable

5-hydroxycloransulam-methyl

(>95%)

96-hr EC50 = >26.3 

NOAEC = 26.3 (algal 

cell density)

447445-04 Supplemental

5-hydroxycloransulam (>97%)

96-hr EC50 = >27.9 

NOAEC = 27.9 (algal 

cell density)

447445-09 Supplemental

Aquatic Vascular Plants

cloransulam (>96%)

Duckweed 

(L. gibba)

14-day EC50 = 0.130 

(frond number)

NOAEC = 0.

447445-15 Acceptable

5-hydroxycloransulam-methyl 

(>95%)

14-day EC50 = 110 

(frond number)

NOAEC = 58.3 (frond 

number & growth rate)

447445-05 Supplemental

5-hydroxycloransulam (>97%)

14-day EC50 = ≥ 100 

(frond number)

NOAEC = 53.6 

447445-10 Acceptable

4.2. Effects to Terrestrial Organisms

Table 4.2 summarizes the most sensitive terrestrial animal toxicity endpoints for cloransulammethyl based on an evaluation of submitted studies. Cloransulam-methyl is categorized as 

practically nontoxic to birds on both an acute oral and subacute dietary exposure basis and it 

practically nontoxic to mammals on an acute oral exposure basis. Cloransulam-methyl is 

practically nontoxic to young adult honey bees on an acute contact exposure basis. Chronic 

toxicity studies of mallard duck (Anas platyrhynchos; MRID 436993-01) and bobwhite quail 

(Colinus virginianus; MRID 436689-05), originally submitted for the registration of 

cloransulam-methyl, were re-evaluated and are included in the summary table below. Available 

terrestrial plant toxicity studies are also reported in this section. Terrestrial plant toxicity studies 

examining vegetative vigor and seedling emergence were submitted for cloransulam-methyl 

(MRID 437154-04) and for the degradates 5-hydroxy-cloransulam-methyl, 5-hydroxycloransulam, and cloransulam (MRID 447445-16). Additionally, one open literature study was 

available on the effects of the degradate cloransulam to soybean growth and development, which 

will be evaluated for possible quantitative and/or qualitative inclusion in the final environmental 

fate and ecological effects risk assessment.
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Table 4.4. Summary of the Most Sensitive Endpoints from Submitted Terrestrial Toxicity 

Studies for Cloransulam methyl. 

TAXON ENDPOINT CHEMICAL/

FORMULATION MRID STUDY CLASSIFICATION

BIRDS

Acute Oral

Bobwhite quail 

(Colinus 

virginianus)

14-day LD50 > 2250 

mg a.i./kg-bw

Cloransulam-methyl 

(97.3%) 430034-07 Acceptable

Sub-Acute Dietary

Mallard Duck 

(Anas 

platyrhynchos)

8-day LC50 > 5620 

mg a.i./kg-diet

Cloransulam-methyl 

(97.3%) 430034-08 Acceptable

Bobwhite quail 

(Colinus 

virginianus)

8-day LC50 > 5620 

mg a.i./kg-diet

Cloransulam-methyl 

(97.3%) 430034-09 Acceptable

Chronic

Mallard Duck 

(Anas 

platyrhynchos)

NOAEC:127 mg 

a.i./kg diet

LOAEC: 485 mg 

a.i./kg diet

Cloransulam-methyl 

(97.3%) 436993-01 Acceptable

Bobwhite quail 

(Colinus 

virginianus)

NOAEC: <654 mg 

a.i./kg diet

LOAEC: 654 mg 

a.i./kg diet

Cloransulam-methyl 

(97.3%) 436689-05 Supplemental

MAMMALS

Acute

Laboratory Rat 

(Rattus norvegicus) 

LD50 > 5000 mg/kgbwCloransulam-methyl 

(97.3%) 430034-13 Acceptable

Chronic

Rat

(Rattus norvegicus)

NOAEL = 10 mg/kgbw

LOEAL = 100 

mg/kg-bw

Based on parental 

systemic toxicity

Cloransulam-methyl 436689-11 Acceptable

TERRESTRIAL INVERTEBRATES

Honey Bee (Apis 

melifera) LD50 > 25 μg a.i./bee Cloransulam-methyl(97.3%) 430034-31 Acceptable

TERRESTRIAL VASCULAR PLANTS: SEEDLING EMERGENCE

Monocot EC25 = >0.0613 lbs 

ai/A

Cloransulam-methyl 

(97.3%) 44744516 Acceptable. 

Dicot (Radish) EC25 = >0.0484 lbs 

ai/A

Cloransulam-methyl 

(97.3%) 44744516 Acceptable. 

TERRESTRIAL VASCULAR PLANTS: VEGETATIVE VIGOR

Monocot (Wheat) NOAEC: 0.0559 lbs 

a.i./A

Cloransulam-methyl 

(97.3%) 44744516 Acceptable. 

Dicot (Radish) EC25: 0.0118 lbs ai/A Cloransulam-methyl 

(97.3%) 44744516 Acceptable
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An acceptable avian single oral dose toxicity study with bobwhite quail (Colinus virginianus) is 

available for cloransulam-methyl (MRID 43003407); the resulting 14-day LD50 was determined 

to be > 2250 mg a.i./kg with a corresponding NOAEL of 2250 mg a.i./kg-bw. No mortality, sign 

of toxicity, or effect on body weight or feed consumption occurred at any dose level. All birds 

were normal in appearance and behavior throughout the study. Two acceptable avian dietary 

toxicity studies were submitted to the Agency for cloransulam-methyl using the bobwhite quail 

(C. virginianus) (MRID 43003409) and mallard duck (Anas platyrhunchos) (MRID 43003408). 

The resulting 8-day LC50 for both studies was >5620 mg a.i./kg-diet, with a corresponding 

NOAEC of 5620 mg a.i./kg-diet. No mortality, effect on body weight gain or feed consumption, 

or any other sublethal effect occurred in either study at any tested concentration level. Based on 

these three studies, cloransulam-methyl is classified practically non-toxic to birds on an acute 

oral and subacute dietary exposure basis. Two toxicity studies on avian reproduction for the 

mallard duck (MRID 43699301) and Bobwhite quail (MRID 43668905) were re-evaluated. 

These studies were originally submitted for the registration of cloransulam-methyl and the 

previous reviews identified effects to mallard ducks; effects to bobwhite quail were not 

identified. The mallard duck (A. platyrhunchos) study revealed a NOAEC of 127 mg ai/kg-diet 

and a LOAEC of 485 mg ai/kg-diet with the most sensitive endpoint being eggshell thickness, 

while the bobwhite quail (C. virginianus) study showed a NOAEC and LOAEC of <654 mg 

ai/kg diet and 654 mg ai/kg diet, respectively. 

Two acute oral toxicity studies on Fischer 344 rats were conducted for the registration of 

cloransulam-methyl. In one study conducted on cloransulam-methyl (97.3%) (MRID 430034-

13), a limit dose of 5,000 mg/kg was administered to both males and females and no significant 

clinical signs of toxicity were reported; the LD50 was >5,000 mg/kg-bw. In a second study 

conducted on the formulation FirstRate®a formulated product with the active ingredient 

cloransulam-methyl only (84.4% a.i.) (MRID 430034-19), a limit dose of 5,000 mg form/kg-bw 

was administered to both male and female rats. Sublethal signs of toxicity included perineal 

urine, fecal soiling, loose stool, and salivation. Based on a lack of mortality, the LD50 was 

>5,000 mg form/kg-bw. 

An acute rat single-oral dose toxicity study was submitted to the Agency for the formulation 

Gauntlet®70 DF (MRID 45388202), a mixture of the two active ingredients cloransulam-methyl 

(8.1%) and sulfentrazone (61.8%). Young adult Sprague-Dawley rats (5 male and 5 female) 

were orally gavaged with Gauntlet®70 DF as a 50% w/v concentration in tap water at the doses 

1,000 mg/kg (males only), 2,500 mg/kg, 4,000 mg/kg, and 5,000 mg/kg. None of the males 

dosed at 1,000 mg/kg died; at 2,500 mg/kg 3 males and 1 female died; at 4,000 mg/kg 3 males 

and 2 females died; and at 5,000 mg/kg all 5 males and females died. Observed symptoms of 

toxicity were abdominal gripping, colonic convulsions, diarrhea, decreased locomotion, 

hypersensitivity to touch/sound, loss of muscle control, oral discharge, tremors, and writhing. 

Necropsy revealed one 5,000 mg/kg male with red urine in its bladder. The LD50 = 2504 mg/kg 

based male mortality, and the LD50 = 3803 mg/kg based on female mortality. This study was 

classified acceptable. 

A two-generation (chronic) reproduction study in male and female Sprague-Dawley rats (MRID 

43668911) was submitted to the Agency for registration of cloransulam-methyl. Test rats 

received nominal daily doses of 0 (control), 10, 100, and 500 mg/kg-bw/day in their feed. Based 
-23 of 85-

on decreased live pups and increased pup deaths, the NOAEL and LOAEL for

developmental/offspring systemic toxicity is 100 mg/kg-diet/day and 500 mg/kg-bw/day, 

respectively. Histopathological alterations of the kidney occurred at 100 mg/kg-bw/day in both 

male and female parental rats. Thus the NOAEL for parental systemic toxicity is 10 mg/kgbw/day. The NOAEL based on developmental/offspring systemic toxicity will be used to assess 

chronic risk of cloransulam-methyl use to mammals. 

Cloransulam-methyl is classified practically non-toxic to young adult honey bees (Apis 

mellifera) based on the one acute contact toxicity study (MRID 430034-31). The resulting LD50 

and NOAEL based on immobile/lethargic bees is >25 μg a.i./bee and 25 μg a.i./bee, respectively.

4.3. Incident Databases Review

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

Avian Incident Monitoring System (AIMS)5 were conducted on July 27, 2010. A total of 54 

incidents associated with cloransulam-methyl use have been reported (all involving plants, 

mostly soybeans and corn) in EIIS. The reported incidents occurred between 1998 and 2005, 

with affected areas ranging from 5 acres to 677.5 acres. Most of the incidents were the result of 

a broadcast application, while a number of others involved spray application. Most of the 

incidents involved the application of FirstRate®, a formulated product with the active ingredient 

cloransulam-methyl only. Moreover, the certainty with which these incidents were a result of 

cloransulam-methyl use was described as highly probable in two incidents, probable in thirty-six 

incidents, possible in thirteen incidents, and unlikely in three incidents. Thirty-seven of the 

incidents were the result of registered use, four were the result of misuse (intentional), seven 

were the result of misuse (accidental); however, it is unknown if the other five incidents resulted 

from misuse or registered uses. Specific details of the incidents are described below. No 

incidents involving birds were reported in the AIMS database for cloransulam-methyl.

In addition to the incidents recorded in EIIS, additional incidents have been reported to the 

Agency in aggregated incident reports. Pesticide registrants report certain types of incidents to 

the Agency as aggregate counts of incidents occurring per product per quarter. Ecological 

incidents reported in aggregate reports include those categorized as „minor fish and wildlife‟ (WB), „minor plant‟ (P-B), and „other non-target‟ (ONT) incidents. „Other non-target‟ incidents 

include reports of adverse effects to insects and other terrestrial invertebrates. For cloransulammethyl, as of July 27, 2010, registrants have reported 102 minor plant incidents associated with 

the use of cloransulam methyl, all of which occurred between 1998 and 2006. The number of 

individual plants affected in these incidents was not specified. Unless additional information on 

these aggregated incidents becomes available, they will be assumed to be representative of 

registered uses of cloransulam-methyl in the risk assessment. All of the reported incidents 

involved terrestrial plants.

The total number of actual incidents associated with the use of cloransulam-methyl may be 

higher than what is reported to the Agency. Incidents may go unreported since effects may not 

 

5

http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm
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be immediately apparent and/or readily attributed to the use of a chemical. As such, the absence 

of incident reports cannot be construed as the absence of incidents.

4.4. Ecosystems Potentially at Risk

The ecosystems at risk are often extensive in scope; therefore, it may not be possible to identify 

specific ecosystems during the development of a nation-wide ecological risk assessment. 

However, in general terms, terrestrial ecosystems potentially at risk could include the treated 

field and immediately adjacent areas that may receive drift or runoff. Areas adjacent to the 

treated field could include cultivated fields, fencerows and hedgerows, meadows, fallow fields or 

grasslands, woodlands, riparian habitats and other uncultivated areas. 

Aquatic ecosystems potentially at risk include water bodies adjacent to, or downstream from, the 

treated field and could include impounded bodies such as ponds, lakes and reservoirs, or flowing 

waterways such as streams or rivers. For uses in coastal areas, aquatic habitat also includes 

marine ecosystems, including estuaries. 

5. Assessment Endpoints

Assessment endpoints represent the actual environmental value that is to be protected, defined by 

an ecological entity (species, community, or other entity) and its attribute or characteristics 

(USEPA, 1998a). For cloransulam-methyl, the ecological entities may include the following: 

birds, mammals, terrestrial-phase amphibians, reptiles, freshwater fish and invertebrates, aquaticphase amphibians, estuarine/marine fish and invertebrates, terrestrial plants, terrestrial 

invertebrates, and aquatic plants. The attributes for each of these entities include growth, 

reproduction, and survival.

6. Conceptual Model

For a pesticide to pose an ecological risk, it must reach ecological receptors in biologically 

significant concentrations. An exposure pathway is the means by which a pesticide moves in the 

environment from a source to an ecological receptor. For an ecological pathway to be complete, 

it must have a source, a release mechanism, an environmental transport medium, a point of 

exposure for ecological receptors, and a feasible route of exposure.

The conceptual model for cloransulam-methyl provides a written description and visual 

representation of the predicted relationships between cloransulam-methyl, potential routes of 

exposure, and the predicted effects for the assessment endpoint. A conceptual model consists of 

two major components: risk hypothesis and a conceptual diagram (USEPA, 1998).

Based on the submitted environmental fate data, cloransulam-methyl is not expected to volatilize 

and persistence in surface waters is uncertain; however, its soil mobility and persistence in the 

soil subsurface is of concern. The compound, and its major degradates, may potentially leach to 

ground water where they could persist (a PGW study is currently under review). Cloransulammethyl is degraded mainly by photolysis in clear shallow water and aerobic microbial 
-25 of 85-

degradation in soil, and degrades by hydrolysis under alkaline conditions. Due to its low Kow

value, cloransulam-methyl is not expected to bioaccumulate in aquatic or terrestrial food chains.

Previous ecological risk assessments for cloransulam-methyl identified risk to listed and nonlisted terrestrial plants from cloransulam-methyl use. As such, listed species in all taxa may 

potentially be affected indirectly due to alterations in their habitat and effects on primary 

productivity. It was determined that all other taxa were not at direct risk from cloransulammethyl use in soybean. However, this determination was based on an incomplete dataset, and 

risks to freshwater and estuarine/marine fish and invertebrates and aquatic plants are uncertain. 

Additionally, effects data on birds, aquatic vascular plants, and terrestrial plants are being reevaluated. These preliminary conclusions are used to derive the risk hypothesis and conceptual 

diagram discussed below.

6.1. Risk Hypothesis

A risk hypothesis describes the predicted relationship among the stressor, exposure, and 

assessment endpoint response along with the rationale for their selection. Because data are either 

not available with which to assess the chronic effects of cloransulam-methyl on aquatic animals 

or data are incomplete with which to assess chronic effects to birds or effects to aquatic vascular 

and nonvascular plants, there is uncertainty regarding potential risk to these taxa. Based on this 

lack of data, and on an anticipated risk determination for listed aquatic plant species, the 

following ecological risk hypothesis is being employed for this ecological risk assessment:

Given the uses of cloransulam-methyl as a pre- and post-emergent herbicide in soybean 

production and its environmental fate properties, there is potential exposure from 

cloransulam-methyl and its degradates of concern to non-target terrestrial and/or 

aquatic organisms. When used in accordance with the label, cloransulam-methyl and its 

degradates may result in potential adverse effects upon the survival, growth, and 

reproduction of non-target terrestrial and/or aquatic organisms. 

6.2. Conceptual Diagram

The environmental fate properties of cloransulam-methyl indicate that runoff, spray drift and 

direct spray represent potential transport mechanisms to aquatic and terrestrial habitats where 

non-target organisms may be either directly or indirectly exposed. These transport mechanisms 

(i.e., sources) are depicted in the conceptual diagrams below (Figures 6.1 and 6.2) along with 

the receptors of concern and the potential attribute changes in the receptors due to exposures of 

cloransulam-methyl. While not captured in Figure 6.2, exposure of terrestrial vertebrates from 

drinking water containing cloransulam-methyl and degradates of concern is also a route of 

exposure that will be assessed.
-26 of 85-

FIGURE 6.1. Conceptual Model for Cloransulam-methyl and Degradate Effects on 

Aquatic Organisms. Dotted Lines Indicate Exposure Pathways that Have a Low Likelihood of 

Contributing to Ecological Risk.

Stressor

Source

Receptors

Attribute

Change

Cloransulam-methyl and Degradates of Concern applied to use site

Spray drift

Aquatic animals

Invertebrates 

Vertebrates

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in nonvascular 

and vascular plants

Reduction in prey

Modification of PCEs

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Atmospheric 

transport

Wet/dry deposition

Soil Leaching to

Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plants

terrestrial 

exposure 

pathways see 

Figure 6.2
-27 of 85-

FIGURE 6.2. Conceptual Model for Cloransulam-methyl and Degradate Effects on 

Terrestrial Organisms. Dotted Lines Indicate Exposure Pathways that Have a Low Likelihood 

of Contributing to Ecological Risk.

7. Analysis Plan

In order to address the risk hypothesis, the potential for adverse effects on the environment will 

be estimated. The use, environmental fate, and ecological effects of cloransulam-methyl will be

characterized and integrated to assess the risks. Risk quotients (RQ) will be derived for 

cloransulam-methyl by dividing estimated environmental concentrations (EEC) by the most 

sensitive endpoint from the relevant, available toxicity data for cloransulam-methyl.

This analysis plan will be revisited and may be revised depending upon a full review of the data 

available in the open literature and the information submitted by the public in response to the 

opening of the Registration Review docket.

Stressor

Source

Attribute

Change

Cloransulam-methyl and Degradates of Concern applied to use site

Direct

application Spray drift

Terrestrial 

vertebrates

Terrestrial 

inverts

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey and food

Modification of PCEs

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related

to habitat

Terrestrial plants

grasses/forbs, fruit, seeds 

(trees, shrubs)

Runoff

Terrestrial 

Vertebrates 

Exposure Media 

& Receptors Soil

Ingestion

Ingestion

Ingestion

Dermal uptake/Ingestion

Atmospheric 

transport

Root uptake/contact

Wet/dry deposition

Ingestion

Leaching to

Groundwater

Irrigation 

water
-28 of 85-

7.1. Stressors of Concern

The stressors, or residues, of concern in this assessment will include cloransulam-methyl and any

degradates determined to be of toxicological concern. Terrestrial and aquatic plants studies are 

available on three of the degradates identified in Section 3.4 determined to be mobile and more 

persistent than the parent: 5-hydroxy-cloransulam-methyl, 5-hydroxy-cloransulam, and 

cloransulam. All available studies on terrestrial plants have been reviewed for both 

cloransulam-methyl and degradates, as well as a study on vascular plants for cloransulammethyl. Based on the available toxicity data, as seen in Table 4.3, cloransulam-methyl (MRID 

44744517) and cloransulam (MRID 44744514; 43668917) are similarly toxic (same order of 

magnitude) to the green alga, P. subcapitata. The toxicity endpoints of 5-hydroxy-cloransulammethyl (MRID 44744504) and 5-hydroxy-cloransulam (MRID 44744509) to P. subcapitata are 

more than four times less toxic. Thus, the stressors of concern for this assessment will include 

cloransulam-methyl and cloransulam, as well as any other degradates determined to be of 

toxicological concern at the time the risk assessment is completed. Modeled exposure estimates 

resulting from cloransulam-methyl use will reflect the predicted environmental fate of 

cloransulam-methyl and any residues of toxicological concern.

 

The Agency does not routinely include an evaluation of mixtures of active ingredients in its 

ecological risk assessments, either those mixtures of multiple active ingredients in product 

formulations or those in the applicator‟s tank. In the case of the product formulations of active 

ingredients (that is, a registered product containing more than one active ingredient), each active 

ingredient is subject to an individual risk assessment for regulatory decision regarding the active 

ingredient on a particular use site. If effects data are available for a formulated product 

containing more than one active ingredient, the data may be used qualitatively or quantitatively 

in accordance with the Agency‟s Overview Document and the Services‟ Evaluation 

Memorandum (USEPA, 2004; USFWS/NMFS, 2004). 

Available toxicity data for environmental mixtures of cloransulam-methyl with other pesticides 

will be presented as part of the ecological risk assessment. It is expected that the toxic effect of 

cloransulam-methyl, in combination with other pesticides used in the environment, is likely to be 

a function of many factors including but not necessarily limited to: (1) the exposed species, (2) 

the co-contaminants in the mixture, (3) the ratio of cloransulam-methyl and co-contaminant 

concentrations, (4) differences in the pattern and duration of exposure among contaminants, and 

(5) the differential effects of other physical/chemical characteristics of the receiving waters (e.g.

organic matter present in sediment and suspended water). Quantitatively predicting the 

combined effects of all these variables on mixture toxicity to any given taxa with confidence is 

beyond the capabilities of the available data and methodologies. However, a qualitative 

discussion of implications of the available pesticide mixture effects data on the confidence of 

risk assessment conclusions will be addressed as part of the uncertainty analysis.

7.2. Measures of Exposure

In order to estimate risks of cloransulam-methyl exposures in aquatic and terrestrial 

environments, all exposure modeling and resulting risk conclusions will be made based on 
-29 of 85-

maximum application rate for the currently registered use [i.e., soybeans] as discussed in Section 

3.2. Measures of exposure are based on aquatic and terrestrial models that estimate 

environmental concentrations of cloransulam-methyl using the maximum labeled application rate 

and application methods that have the greatest potential for off-site transport of the chemical. 

The models used to generate aquatic estimated environmental concentrations (EEC) are the 

Pesticide Root Zone Model (PRZM) coupled with the EXposure Analysis Model System 

(EXAMS). The EECs will be based on the parent compound plus the degradate cloransulam, as 

well as any other degradates that are determined to be of toxicological concern based on 

information available at the time of the assessment. Environmental inputs for the total toxic 

residues in aquatic systems (cloransulam-methyl + cloransulam) will be calculated using the total 

residue approach (TR). The model used to produce terrestrial EECs on food items is T-REX. 

The model used to derive EECs relevant to terrestrial and wetland plants is TerrPlant. These 

models are parameterized using relevant reviewed registrant-submitted environmental fate data.

PRZM (v3.12.2, May 2005) and EXAMS (v2.98.4.6, April 2005) are screening simulation 

models coupled with the graphical user interface, PE (v5.0, November 2006) to generate daily 

exposures and 1-in-10-year EECs of cloransulam-methyl (and residues of concern) that may 

occur in surface water bodies adjacent to application sites receiving cloransulam-methyl through 

runoff and spray drift. PRZM simulates pesticide application, movement and transformation on 

an agricultural field and the resultant pesticide loadings to a receiving water body via runoff, 

erosion, and spray drift. EXAMS simulates the fate of the pesticide and resulting concentrations

in the water body. The standard watershed geometry used for ecological pesticide assessments 

assumes application to a 10-hectare agricultural field that drains into an adjacent 1-hectare water 

body that is 2 meters deep (20,000 m3volume) with no outlet. The composite model 

PRZM/EXAMS is used to estimate screening-level exposure of aquatic organisms to 

cloransulam-methyl. The measure of exposure for aquatic species is the 1-in-10-year peak or 

rolling mean concentration. The 1-in-10-year peak is used for estimating acute exposures of 

direct effects to aquatic organisms. The 1-in-10-year 60-day mean is used for assessing the 

effects to fish and aquatic-phase amphibians from chronic exposure. The 1-in-10-year 21-day 

mean is used for assessing the effects on aquatic invertebrates from chronic exposure.

Exposure estimates for terrestrial animals assumed to be in the target area or in an area exposed 

to spray drift are derived using the T-REX model (version 1.4.1, 10/08/2008). This model 

incorporates the Kenaga nomograph, as modified by Fletcher et al. (1994), which is based on a 

large set of actual field residue data. The upper limit values from the nomograph represent the 

95th percentile of residue values from actual field measurements (Hoerger and Kenaga 1972). 

The Fletcher et al. (1994) modifications to the Kenaga nomograph are based on measured field 

residues from 249 published research papers, including information on 118 species of plants, 121 

pesticides, and 17 chemical classes. For input into T-REX, the default foliar dissipation half-life 

of 35 days will be used due to insufficient foliar dissipation rate data on cloransulam-methyl. If 

terrestrial plant toxicity data are available, EECs for terrestrial plants inhabiting dry and wetland 

areas are derived using TerrPlant (version 1.2.2, 12/26/2006). This model uses estimates of 

pesticides in runoff and in spray drift to calculate EECs. EECs are based upon solubility, 

application rate and minimum incorporation depth. 
-30 of 85-

The AgDRIFT spray drift model (v2.01; May, 2001) is used to assess exposures of organisms to 

cloransulam-methyl deposited on terrestrial habitats by spray drift.

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

upper bound estimate of exposure using cloransulam-methyl‟s solubility, the most sensitive acute 

and chronic avian toxicity endpoints (bobwhite quail LD50 >2250 mg a.i./kg-bw; NOAEC 

unavailable) and the most sensitive acute and chronic mammalian toxicity endpoints (laboratory 

rat LD50 >5,000 mg a.i./kg-bw and NOAEL = 100 mg a.i./kg-bw, respectively). Appendix E 

provides a description of the model and assumptions in deriving an upper bound exposure 

estimate. At a pH of 8.5, cloransulam-methyl‟s reported solubility in water at 20°C is 3400 

mg/L (MRID 43668933). Drinking water exposure alone was determined to be a potential 

concern for mammals on a chronic basis, and a potential pathway of concern for birds on chronic 

basis due to non-definitive endpoints (see Appendix E for model results). Although this model 

flags acute exposure to birds and mammals as a potential concern based on potential estimated 

environmental concentrations in drinking water at pH 8.5 and above, toxicity data demonstrate 

that acute/subacute effects from cloransulam-methyl exposure is not likely a concern for birds or 

mammals. This pathway will be explored further with the development of SIP v.2.0 in the 

Ecological Risk Assessment for cloransulam-methyl. 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. 

7.3. Measures of Effect

Ecological effects data are used as measures of direct and indirect effects to biological receptors. 

As discussed previously, data are obtained from registrant-submitted studies or from literature 

studies identified by ECOTOX. The ECOTOX database provides more ecological effects data in 

an attempt to bridge existing data gaps. ECOTOX is a source for locating single chemical 

toxicity data and potential chemical mixture toxicity data for aquatic life, terrestrial plants, and 

wildlife. ECOTOX was created and is maintained by the USEPA, Office of Research and 

Development, and the National Health and Environmental Effects Research Laboratory's MidContinent Ecology Division.

Also as discussed previously, information on the potential effects of cloransulam-methyl on nontarget animals is also collected from the Ecological Incident Information System (EIIS; USEPA, 

2007c). The EIIS is a database containing adverse effect (typically mortality) reports on nontarget organisms where such effects have been associated with the use of pesticides.

Incidents reported in the aggregate incident reports and the Avian Incident Monitoring System 

(AIMS) will also be searched again. AIMS is a database administered by the American Bird 

Conservancy with partial funding from EPA). It contains publicly available data on reported 

avian incidents involving pesticides

(http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm).

Where available, sub-lethal effects observed in both registrant-submitted and open literature 

studies will be evaluated qualitatively. Such effects may include behavioral changes (e.g., 
-31 of 85-

lethargy and changes in coloration). Quantitative assessments of risks, though, are limited to 

those endpoints that can be directly linked to the Agency‟s assessment endpoints of impaired 

survival, growth and reproduction.

The assessment of risk for direct effects to non-target organisms makes the assumption that 

toxicity of cloransulam-methyl to birds is similar to terrestrial-phase amphibians and reptiles. 

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

The acute measures of effect used for animals in this assessment are the LD50, LC50 and EC50. 

LD stands for "Lethal Dose", and LD50 is the amount of a material, given all at once, that is 

estimated to cause the death of 50% of the test organisms. LC stands for “Lethal Concentration” 

and LC50 is the concentration of a chemical that is estimated to kill 50% of the test organisms. 

EC stands for “Effective Concentration” and the EC50 is the concentration of a chemical that is 

estimated to produce a specific effect in 50% of the test organisms. Endpoints for chronic 

measures of exposure for listed and non-listed animals are the NOAEL/NOAEC and NOEC. 

NOAEL stands for “No Observed-Adverse-Effect-Level” and refers to the highest tested dose of 

a substance that has been reported to have no harmful (adverse) effects on test organisms. The 

NOAEC (i.e., “No-Observed-Adverse-Effect-Concentration”) is the highest test concentration at 

which none of the observed effects were statistically different from the control. The NOEC is 

the No-Observed-Effects-Concentration. For non-listed plants, only acute exposures are 

assessed (i.e., EC25 for terrestrial plants and EC50 for aquatic plants); for listed plants either the 

NOAEC or EC05 is used. 

7.4. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effect characterizations to 

determine the potential ecological risk from the use of cloransulam-methyl and the likelihood of 

direct and indirect effects to non-target organisms in aquatic and terrestrial habitats. The 

exposure and effects data are integrated in order to evaluate potential adverse ecological effects 

on non-target species. For the assessment of cloransulam-methyl risks, the risk quotient (RQ) 

method is used to compare estimated exposure and measured toxicity values. Acute and chronic 

EECs are divided by acute and chronic toxicity values. The resulting RQs are then compared to 

the Agency‟s Levels of Concern (LOC) (USEPA 2004). These criteria are used to indicate when 

cloransulam-methyl‟s use, as directed on the labels, has the potential to cause adverse direct or 

indirect effects to non-target organisms. In addition, incident data from EIIS, aggregate incident 

reports, and AIMS will be considered as part of the risk characterization.

7.5. Deterministic and Probabilistic Assessment Methods

The quantitative assessment of risk will primarily depend on the deterministic point estimatebased approach described in the risk assessment. Depending on the risk manager‟s need for 

additional information regarding risk, an effort will be made to further qualitatively describe risk 

using probabilistic tools that the Agency has developed. These tools have been reviewed by 

FIFRA Scientific Advisory Panels (http://www.epa.gov/scipoly/sap/index.htm) and have been 
-32 of 85-

deemed as appropriate means of refining assessments where deterministic approaches have 

identified risks.

7.6. 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 cloransulam-methyl. This assessment will be conducted in accordance with 

the Overview Document (USEPA, 2004), provisions of the ESA, and the Services‟ Endangered 

Species Consultation Handbook (USFWS/NMFS, 1998).

The assessment of effects associated with the registration of cloransulam-methyl is based on an 

action area. The action area is considered to be the area directly or indirectly affected by the 

federal action, as indicated by the exceedance of Agency Levels of Concern (LOCs) used to 

evaluate direct or indirect effects. The Agency‟s approach to defining the action area under the 

provisions of the Overview Document (USEPA, 2004) considers the results of the risk 

assessment process to establish boundaries for that action area with the understanding that 

exposures below the Agency‟s defined LOCs constitute a no-effect threshold. For the purposes 

of this assessment, attention will be focused on the footprint of the action (i.e., the area where 

cloransulam-methyl application occurs), plus all areas where offsite transport (i.e., spray drift, 

runoff, etc.) may result in potential exposure that exceeds the Agency‟s LOCs. Specific 

measures of ecological effect that define the action area for listed species include any direct and 

indirect effects and/or potential modification of its critical habitat, including reduction in 

survival, growth, and reproduction as well as the full suite of sub-lethal effects available in the 

effects literature. Therefore, the action area extends to a point where environmental exposures 

are below any measured lethal or sub-lethal effect threshold for any biological entity at the whole 

organism, organ, tissue, and cellular level of organization. In situations where it is not possible 

to determine the threshold for an observed effect, the action area will be assumed to encompass 

the entire United States.

7.7. Drinking Water Assessment

A drinking water assessment will be conducted to support future human health dietary risk 

assessments of cloransulam-methyl. The drinking water assessment will incorporate model 

estimates of cloransulam-methyl residues of concern, including cloransulam-methyl and any 

degradates of toxicological concern, in surface water and ground water. Concentrations of 

cloransulam-methyl and its residues of concern in surface water will be estimated using 

PRZM/EXAMS (see description in Section 7.2). Ground water exposure estimates for 

cloransulam-methyl and its residues of concern will be estimated using the Screening 

Concentration in Ground Water (SCI-GROW) model (v.2.3, July 2003) followed by a higher tier 

model if necessary. The drinking water assessment will also include a summary of available 

surface and ground water monitoring data.
-33 of 85-

7.8. Preliminary Identification of Data Gaps

7.8.1. Environmental Fate

The studies submitted to fulfill environmental fate data requirements for cloransulam-methyl are 

not sufficient for an exposure assessment. Six guideline requirements have not been satisfied. 1) 

The current supplemental anaerobic aquatic metabolism study will be used for risk assessment 

purposes, however an additional acceptable study in an acidic (low pH) system is required to 

fulfill the guideline and better understand the potential variability in the biotic degradation of 

cloransulam-methyl in oxygen limiting aquatic environments. 2) There is no anaerobic soil 

metabolism study. 3) There is no acceptable terrestrial field dissipation study, currently reviewed 

studies are classified as supplemental but will be used for risk assessment. There is an additional 

terrestrial field dissipation study that was submitted to the Agency and is currently under review. 

4) There is no acceptable frozen storage stability study, and an aerobic soil metabolism study 

(MRID 43003434), showed that extracted residues decreased as a result of frozen storage prior to 

analysis. It is important to have an acceptable frozen storage stability study using the same soils 

as the terrestrial field dissipation study in order to be confident that any degradation measured in 

the test system was due solely to the environment of that test system, and not due to handling and 

storage. 5) Acceptable aerobic aquatic metabolism data are not available. A submitted study 

(MRID 44265302) was classified as unacceptable and cannot be used for risk assessment. 6) 

Although not crucial for risk assessment purposes, the Agency does require that an acceptable 

method and two independent laboratory validations (ILVs) be submitted for sediment.

Table 7.2 identifies studies by MRID that offer data for each guideline requirement, as well as 

study classifications and whether or not further data are needed in order to support risk 

assessment (i.e., whether there is a data gap). Draft Data Call-In (DCI) tables for requested data 

are provided in APPENDIX F.

TABLE 7.1. Environmental Fate Data Requirement Table for Cloransulam-methyl.

OPPTS 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Classification Data Gap? Comment

835.2120 Hydrolysis 43003432 Acceptable No

835.2240 Aqueous photolysis 43715402 Acceptable No

835.2410 Soil photolysis 43760001 Supplemental No

Study has been reclassified as 

SUPPLEMENTAL because there are 

significant differences in the half-lives of the 

two labeled studies. Light intensity and 

aerobic soil metabolism appeared to be 

dominant, however when corrected for 

metabolism and day light at 40oN half-lives 

are still significantly different.

835.4100 Aerobic soil 

metabolism

43003433 Acceptable

No

Classified acceptable in EUP memo (Clem to 

Taylor 12/23/95)

43216602 

(aka 

43003435)

Supplemental

Supplemental aerobic metabolism data on 16 

soils from an adsorption/desorption study.

43003434 Supplemental Supplemental data (same study as MRID 
-34 of 85-

OPPTS 

Guideline Data Requirement

Submitted 

Studies 

(MRID)

Classification Data Gap? Comment

43003433)

43003435 Supplemental Supplemental data (Same study as MRID 

43216602)

44809201 Under review

Study was conducted using soils form two 

sites (IA & IN) that were previously used for 

flufanacet and flumetsulam PGW studies, 

respectively.

Currently under review.

835.4200 Anaerobic soil 

metabolism No data -- Yes

1997 fate assessment (D223558+) stated that 

anaerobic aquatic metab study was submitted 

in place of the anaerobic soil to fulfill this 

requirement. Current data requirements 

include both studies.

835.4300 Aerobic aquatic 

metabolism 44265302 Not Acceptable Yes

Multiple deficiencies including inadequate 

duration of study and failure to demonstrate 

patterns of formation and decline of 

degradates.

835.4400 Anaerobic aquatic 

metabolism 43715403 Supplemental Yes

Data are needed for two additional sediment 

systems, one each at a neutral and an acidic 

pH.

835.1230 Adsorption/ 

desorption and 

leaching

43003434 Acceptable

No

Also includes ancillary data on aerobic soil 

metabolism.

43003435 

and 

43216602

Acceptable Also includes ancillary data on aerobic soil 

metabolism.

835.6100

Terrestrial field 

dissipation

43760002 Supplemental

Yes

A frozen storage stability study has not been 

submitted.

44231501 Under review Currently under review

Freezer storage 

stability No data --

Data from another study (MRID 43003434) 

show extracted residues decreased as a result 

of frozen storage prior to analysis. An 

acceptable freezer storage stability study using 

the soils used in the TFD studies is needed.

Analytical method 

– soil 44231502 Acceptable No

Analytical method 

- water 44231503 Acceptable No

Analytical method 

- sediment No data -- Yes

835.7100

Prospective 

Ground Water 

Monitoring

46161601 Under review --

Study was submitted as a condition of 

registration. Currently under review.

850.1730 Fish 

bioconcentration No data -- No

Low Kow value indicates a low potential for 

cloransulam-methyl to bioconcentrate in fish, 

therefore a study is not required under 40 

CFR part 158 Subpart G.
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7.8.2. Effects Data

Although many submissions have been made to provide studies on the effects of cloransulammethyl to aquatic and terrestrial organisms, data gaps remain (Tables 7.3-7.5). Data gaps 

include the following: avian acute oral, avian reproduction, freshwater invertebrate, freshwater 

invertebrate life-cycle, freshwater fish early life stage, terrestrial plant tier II vegetative vigor, 

and aquatic vascular and nonvascular plant toxicity studies. These data gaps are discussed below. 

TABLE 7.2. Available Ecological Effects Data for Terrestrial Animals Exposed to 

Cloransulam-methyl and Remaining Data Gaps.

Guideline Description MRID/

Accession

Classification Data 

Gap?

Comments

850.2100 Avian acute oral 

toxicity

430034-07 Acceptable Yes* *Avian acute oral toxicity data 

are not available for 

passerines, which are required 

under the new 40 CFR Part 

158. Therefore, this is 

identified as a data gap.

** Adverse significant effects 

were found at the lowest 

treatment concentration.

850.2200 Avian sub-acute 

dietary toxicity 

430034-08 Acceptable No

430034-09 Acceptable

850.2300 Avian reproduction 436689-05 Supplemental Yes **

436993-01 Acceptable No 

850.3020 Honeybee acute 

contact toxicity

430034-31 Acceptable No
-36 of 85-

TABLE 7.3. Available Ecological Effects Data for Aquatic Animals Exposed to 

Cloransulam-methyl and Remaining Data Gaps.

Guideline Description MRID/ 

Accession Classification Data Gap? Comments

850.1075 Freshwater fish –

Acute toxicity 

430034-11 Acceptable

No

* Toxicity data for freshwater 

fish and invertebrates, which 

are required, are not currently 

available. Therefore, these are 

identified as data gaps.

**Conditional data 

requirement not triggered 

based on ecotoxicity data, 

predicted EECs, fate 

properties, and use pattern 

criteria

430034-10 Acceptable

850.1010

Freshwater 

invertebrates –

Acute toxicity

430034-12 Invalid Yes*

850.1075

850.1025

850.1035

Estuarine and Marine 

Organisms –

Acute toxicity 

437189-01 Acceptable

437189-02 Acceptable No

437189-03 Acceptable

850.1300

Freshwater 

invertebrate –

life cycle test

None Not applicable Yes*

850.1350

Saltwater invertebrates 

–

life cycle test

None Not applicable No**

850.1400 Freshwater fish –

early life stage test None Not applicable Yes*

850.1400 Saltwater fish –

early life stage test None Not applicable No**

850.1500 Fish life cycle test None Not applicable No**
-37 of 85-

TABLE 7.4. Available Ecological Effects Data for Plants Exposed to Cloransulam-methyl

and Remaining Data Gaps.

Guideline Description MRID Classification Data 

Gap? Comments

850.4100

Terrestrial Plant 

toxicity: Tier I seedling 

emergence

None Not applicable No

Tier I toxicity data for 

terrestrial plants are not 

required for known 

phytotoxicants.

850.4225

Terrestrial Plant 

toxicity: Tier II seedling 

emergence

44744516 Acceptable Yes

The study was conducted 

using the TGAI (typical grade 

active ingredient) instead of 

the required TEP (typical enduse product)

850.4150

Terrestrial Plant 

toxicity: Tier I 

vegetative vigor

None Not applicable No

Tier I toxicity data for 

terrestrial plants are not 

required for known 

phytotoxicants.

850.4250

Terrestrial Plant 

toxicity: Tier II

vegetative vigor

44744516 Acceptable Yes

The study was conducted 

using the TGAI (typical grade 

active ingredient) instead of 

the required TEP (typical enduse product); Study duration 

was not reported

850.5400 Aquatic Plant Growth: 

algae 44744517 Acceptable Yes

Data are required for four 

species: a freshwater green 

alga, freshwater diatom, 

nitrifying cyanobacteria, and 

saltwater diatom. Data were 

only submitted for the parent 

compound on a green alga.

850.4400 Aquatic Plant Growth: 

vascular plants 43668916 Invalid Yes

The results of this study do not 

fully meet guideline standards 

for an aquatic plant growth 

test using L. gibba.

Avian Acute Oral and Reproduction Toxicity 

Acceptable acute avian oral toxicity data were submitted for exposures of bobwhite quail and 

mallard duck to cloransulam-methyl; however, data are not available for passerines, which are 

required under the new 40 CFR Part 158 (Oct. 26, 2007) data requirements for conventional 

pesticides (72 FR 60934; USEPA 2007d). The new Part 158 data requirements specify that 

avian acute oral toxicity data (OCSPP Guideline 850.2100) be submitted for either a mallard 

duck or bobwhite quail and a passerine species. Due to lack of reported toxicity in mallard duck 

and bobwhite quail to cloransulam-methyl on an acute oral and subacute dietary exposure basis, 

significant acute oral effects to passerines are not expected. Unless new information suggests 

passerines might be sensitive to cloransulam-methyl, EFED will not otherwise (i.e. in the 

absence of data) assume acute risk for passerine species. 
-38 of 85-

Under the 40 CFR Part 158 (Oct. 26, 2007) data requirements for conventional pesticides, avian 

reproduction data are required on waterfowl and upland game species (OCSPP Guideline

850.2300). Data for cloransulam-methyl were reviewed for both an upland game species 

(bobwhite quail), MRID 43668905, and waterfowl species (mallard duck), MRID 436993-01. 

The bobwhite quail study resulted in significant adverse effects at the lowest treatment 

concentration. The NOAEC for the bobwhite quail was statistically determined to be <654 mg 

a.i./kg-diet based on number of eggs set, number of viable embryos, number of live embryos, 

number hatched, and hatchling survival. The preliminary NOAEC based on these five 

parameters in the mallard study is 1,505 mg a.i./kg-diet, indicating that for certain parameters the 

bobwhite quail is more sensitive to cloransulam-methyl. Therefore, since a preliminary review 

suggests that the bobwhite study failed to determine a NOAEC, and because additional avian 

reproduction data on bobwhite quail for cloransulam-methyl would result in a more sensitive 

avian reproductive endpoint for certain parameters, we recommend requesting a second avian 

reproduction study with the bobwhite quail for cloransulam-methyl at this time. 

Acute and Chronic Freshwater Invertebrate and Fish Studies

 

An acute freshwater invertebrate study (OCSPP Guideline 850.1010), a chronic freshwater 

invertebrate life cycle study (OCSPP Guideline 850.1300), and a chronic freshwater fish early 

life stage study (OCSPP Guideline 850.1400) are all required for registration of pesticides with 

outdoor uses (CFR Part 158). To meet the freshwater fish early life stage study requirement, 

data must be submitted on one of the two species tested for the acute freshwater fish toxicity 

studies. If the test species is different than the two species used for the freshwater fish acute 

toxicity tests, a 96-hour LC50 on that species must also be provided. Currently, only one of the 

three aforementioned studies has been submitted, i.e., an acute freshwater invertebrate study 

(MRID 430034-12), however, this study was classified invalid. As such, we recommend 

requesting toxicity data on acute effects to freshwater invertebrates, and chronic effects to 

freshwater invertebrates and fish. In the absence of these data, EFED will assume risk to these 

taxa from use of cloransulam-methyl.

Chronic toxicity studies for cloransulam-methyl with estuarine/marine fish or invertebrates are 

not available at this time. In the absence of this data, an assumption of chronic risk to these taxa 

will be made using an acute-to-chronic ratio (ACR). A chronic effects endpoint for either 

estuarine/marine fish or invertebrates will be derived by applying a ratio of acute and chronic 

freshwater endpoints (from the same species) to an acute estuarine/marine endpoint. Risk to 

estuarine/marine fish and invertebrates will be based on the newly derived endpoint. 

Terrestrial Plant Studies 

Terrestrial plant toxicity studies are required for registration of pesticides with outdoor uses 

(CFR Part 158). For known phytotoxicants, Tier II vegetative vigor (OSCPP 850.4100) and Tier 

II seedling emergence (OCSPP 850.4150) studies are required on a TEP to investigate the effects 

of the pesticide end-use product on the growth and survival of terrestrial plants. A seedling 

emergence study, MRID 437154-04, and vegetative vigor study, MRID 437154-04, were 

reviewed. Because the seedling emergence study was conducted on the TGAI and not the TEP, 
-39 of 85-

the study will not fully meet registration requirements for a phytotoxicant. Likewise, the 

available vegetative vigor study was conducted on the TGAI and not a TEP; additionally, this 

study had notable Guideline deviations (e.g. study duration not reported) and thus does not 

appear to fully meet Guideline standards nor meet registration requirements. Because the 

toxicity of cloransulam-methyl to terrestrial plants may be enhanced when formulated as a 

product with additional ingredients, such as surfactants, and due to the number of reported 

incidents on terrestrial plants, we recommend requesting both a second Tier II seedling 

emergence and Tier II vegetative vigor toxicity study conducted on a TEP containing the single 

active ingredient cloransulam-methyl (i.e., Riverdale® and Firstrate® formulations). In the 

absence of these data, the extent of risks to plants could potentially be underestimated. 

Statement of Possible Future Data Call In (DCI) for Plant Reproductive Study on 

Acetohydroxyacid Synthetase (AHAS) Inhibitors (historically referred to as Acetolactate 

Synthase (ALS) Inhibitors)

There is evidence that some Sulfonylurea herbicides (SUs) have been associated with effects on 

reproduction in plants under field conditions (See chlorsulfuron RED (D330621)). It is uncertain 

at this time whether the Agency‟s standard vascular plant toxicity testing provides endpoints that

are adequately protective of possible reproduction effects to plants resulting from applications of 

SUs. The uncertainty lies in whether reproductive effects occur at rates lower than the vegetative 

vigor endpoint. To address this uncertainty, plant reproduction testing is now being requested by 

EPA‟s Environmental Fate and Effects Division (EFED) in the Office of Pesticide Programs 

(OPP) for all SUs.

It is possible that reproduction effects to plants associated with SUs are mediated by the 

presently understood mechanism of action for this class of herbicide which is inhibition of 

Acetohydroxyacid Synthetase (AHAS). The inhibition of AHAS disrupts the synthesis of 

branched chain amino acids (valine, leucine, and isoleucine) that are important for a variety of 

plant cellular functions. Historically, this class of herbicides has been referred to as Acetolactate 

Synthase (ALS) inhibitors (specifically referring to inhibition of the formation of acetolactate in

the synthesis of valine and leucine), but this ignores the role of AHAS in isoleucine synthesis 

and is therefore referred to herein as AHAS inhibitors. If AHAS mediation for reproduction 

effects is factual for the SUs, then other chemical classes which also exert herbicidal effects 

through AHAS inhibition may potentially exhibit effects on plant reproduction.

At this point the Agency believes that there is insufficient data to determine if, in the case of 

SUs, reproduction effects from available data are reproducible in the proposed testing scheme 

and whether any observed effects would be adequately represented by the more routinely tested 

effects endpoints for plants. The Agency expects that the currently required testing for SUs will 

be important in making that determination. Until then, the Agency is looking for public input 

regarding scientific evidence for the conservation of reproduction concerns across the other 

AHAS inhibiting herbicides. 

As SU testing results become available, the Agency will compare the results with other standard 

effects endpoints and review any public input on evidence associating AHAS inhibition with 

reproduction effects for other chemical classes of herbicides. This will inform the Agency in 
-40 of 85-

making decisions regarding the need for any expansion of plant reproduction testing with a larger 

set of AHAS inhibiting herbicide chemicals.

Vascular Aquatic Plant and Alga Studies

Aquatic plant toxicity studies and associated risk analysis of plants are required for registration 

of pesticides with outdoor uses (40 CFR Part 158). For known phytotoxicants, a Tier II aquatic 

vascular plant toxicity study (OCSPP Guideline 850.4400) and four Tier II non-vascular plant 

toxicity studies (OCSPP Guideline 850.5400) on either the TGAI or TEP are required. The 

available vascular aquatic plant study with the TEP using L. gibba, MRID 436689-16, was 

reviewed and does not fully meet OCSPP Guideline standards due to a number of noted 

deficiencies and uncertainties (i.e., test substance instability, solvent control contamination, and 

solvent control effect uncertainty). In contrast, the available freshwater green alga toxicity study 

(MRID 447445-17) is classified "acceptable"; however, three more nonvascular plant studies are 

required, i.e., freshwater diatom, saltwater diatom, and a nitrifying cyanobacteria. Because 

cloransulam-methyl is a known phytotoxicant, EFED recommends requesting another toxicity 

study on an aquatic vascular plant and three additional toxicity studies on nonvascular aquatic 

plants. EFED will assume risk to aquatic plants (vascular and nonvascular) in the absence of 

these data. 
-41 of 85-

8. References

ChemBlink. 2010. Online database for chemicals from around the world (cloransulam-methyl 

structure) Accessed on July 20, 2010. Online at: 

http://www.chemblink.com/structures/147150-35-4.gif.

Fletcher, J.S., J.E. Nellessen, and T.G. Pfleeger. 1994. Literature review and evaluation of the 

EPA food-chain (Kenaga) nomogram, an instrument for estimating pesticide residues on 

plants. Environ. Tox. Chem. 13:1383-1391.

Herbicide Resistance Action Committee (HRAC). 2009. Classification of Herbicides According 

to Mode of Action. Accessed on August 20, 2010. Online at 

http://www.hracglobal.com/Publications/ClassificationofHerbicideModeofAction/tabid/2

22/Default.aspx.

Hoerger, F. and E. E. Kenaga. 1972. Pesticide Residues on Plants: Correlation of 

Representative Data as a Basis for Estimation of their Magnitude in the Environment. In

F. Coulston and F. Korte, eds., Environmental Quality and Safety: Chemistry, 

Toxicology, and Technology, Georg Thieme Publ., Stuttgart, West Germany, pp. 9-28.

University of Minnesota Extension (UM Extension). 2009. Herbicide and Nonherbicide Injury 

Symptoms on Spring Wheat and Barley: Amino Acid Synthesis Inhibitors. Accessed 

August 8, 2010. Online at:

http://www.extension.umn.edu/distribution/cropsystems/components/6967_01g.html

USDA. 1997. Usual Planting and Harvesting Dates for U.S. Field Crops. National Agricultural 

Statistics Service. United States Department of Agriculture. Accessed August 9, 2010. 

Online at: http://usda.mannlib.cornell.edu/usda/nass/planting/uph97.pdf 

USEPA. 1997. Cloransulam-methyl Risk Assessment. DP Barcode: D223558; D223605. U.S. 

Environmental Protection Agency, Office of Pesticide Programs. August 8, 1997.

USEPA. 1998. Guidelines for Ecological Risk Assessment. Risk Assessment Forum, Office of 

Research and Development, Washington, D.C. EPA/630/R-95/002F. April 1998. 

http://cfpub.epa.gov/ncea/cfm/recordisplay.cfm?deid=30759

USEPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. U.S. Environmental Protection Agency, Office of Prevention, Pesticides and 

Toxic Substances, Office of Pesticide Programs, Washington DC. January 23, 2004.

USEPA. 2007a. Ecological Incident Information System. 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf

USEPA. 2007b. ECOTOXicology Database. Office of Research and Development National 

Health and Environmental Effects Research Laboratory‟s (NHEERL‟s) Mid-Continent 

Ecology Division (MED). http://cfpub.epa.gov/ecotox/.
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USEPA. 2010. Cloransulam-methyl (129116): Screening Level Usage Analysis. U.S. 

Environmental Protection Agency, Office of Prevention, Pesticides and Toxic 

Substances, Biological and Economic Analysis Division. Jan 21, 2010.

U.S. Fish and Wildlife Service (USFWS) and National Marine Fisheries Service (NMFS). 1998. 

Endangered Species Consultation Handbook: Procedures for Conducting Consultation 

and Conference Activities Under Section 7 of the Endangered Species Act. Final Draft. 

March 1998.

USFWS/NMFS/NOAA.2004. 50 CFR Part 402. Joint Counterpart Endangered Species Act 

Section 7 Consultation Regulations; Final Rule. Federal Register Volume 69. Number 

20.Pages 47731-47762. August 5, 2004.

U.S. Geological Survey (USGS). 2010. Pesticide Use Maps. U.S. Geological Survey, National 

Water-Quality Assessment (NAWQA) Program, Pesticide National Synthesis Program. 

Accessed on July 20, 2010. Online at: 

http://water.usgs.gov/nawqa/pnsp/usage/maps/compound_listing.php?year=02
-43 of 85-

SUBMITTED ENVIRONMENTAL FATE STUDIES:

MRID: Citation:

43003432 Zabik, S. (1993) Hydrolysis of XDE-565 in Three Water Systems: Buffered at pH 5, 7, and 9, Natural 

Water and Soil Slurry: Lab Project Number: ENV91086. Unpublished study prepared by DowElanco. 82 

p. 

43715402 Cook, W.; Saunders, D. (1995) Aqueous Photolysis of XDE-565: Lab Project Number: ENV92002. 

Unpublished study prepared by DowElanco. 171 p. 

44265301 Cook, W.; Powers, F. (1996) Photodegradation of Cloransulam-methyl in Aqueous Buffer: (Final 

Report): Lab Project Number: ENV96085. Unpublished study prepared by DowElanco. 83 p. 

43760001 Merritt, D.; Cook, W. (1995) Photodegradation of DE-565 (Cloransulam-Methyl) on Soil: Lab Project 

Number: ENV92003: GH-C 3668. Unpublished study prepared by DowElanco North American 

Environmental Chemistry Lab. 89 p. 

43003433 Wolt, J.; Smith, J.; Sims, G. (1993) Aerobic Metabolism of (carbon 14)-(Phenyl)-and (Pyrimidine)-

XDE-565 in Two Soils: Lab Project Number: ENV91095. Unpublished study prepared by DowElanco. 

91 p. 

43216601 Smith, J.; Wolt, J.; Sims, G. (1993) A Kinetic Study of XDE-565 Sorption and Degradation on Sixteen 

Soils: MRID 43003434: Lab Project Number: ENV91095.01: GH-C 3095. Unpublished study prepared 

by DowElanco. 53 p. 

44809201 Batzer, F.; Yoder, R. (1999) Aerobic Soil Metabolism of Cloransulam-methyl on Soils from La Porte, 

IN and Janesville, IA: Lab Project Number: 980072. Unpublished study prepared by Dow AgroSciences 

LLC. 63 p. 

43715403 Erhardt-Zabik, S.; Havens, P.; Hawes, K. (1995) The Anerobic Aquatic Metabolism of XDE-565: Lab 

Project Number: ENV91110. Unpublished study prepared by DowElanco. 87 p. 

44265302 Hawes, K.; Ulmer, J. (1997) The Aerobic Aquatic Metabolism of DE-565: (Final Report): Lab Project 

Number: ENV96033. Unpublished study prepared by DowElanco. 70 p. 

43003434 Smith, J.; Wolt, J.; Sims, G. (1993) A Kinetic Study of XDE-565 Sorption and Degradation on Sixteen 

Soils: Lab Project Number: ENV91095.01. Unpublished study prepared by DowElanco. 51 p. 

43003435 Cleveland, C.; Ostrander, J.; Miller, J. (1993) Laboratory Mobility Assessments of XDE-565 and 

Metabolites: Lab Project Number: ENV92042: ENV93086. Unpublished study prepared by DowElanco. 

108 p. 

43216602 Cleveland, C.; Ostrander, J.; Miller, J. (1993) Laboratory Mobility Assessments of XDE-565 and 

Metabolites: MRID 43003435: Lab Project Number: ENV92042: ENV93086: GH-C 3125. Unpublished 

study prepared by DowElanco. 102 p. 

43760002 Zabik, J.; Miller, J.; Ostrander, J.; et al. (1995) Amended Report for Terrestrial Field Dissipation of 

Cloransulam-Methyl: Lab Project Number: ENV93031: GH-C 3621R. Unpublished study prepared by 

DowElanco North American Environmental Chemistry Lab. 224 p. 

44231501 van Wesenbeeck, I.; Bormett, G.; Roberts, D. (1996) Terrestrial Field Dissipation of Cloransulammethyl: (Final Report): Lab Project Number: ENV95017: GRM95.10. Unpublished study prepared by 

DowElanco; A&L Great Lakes Labs; and MVTL Labs. 240 p. 

44231502 Duebelbeis, D.; Thomas, A. (1996) Method Validation Report for the Determination of Residues of 

Cloransulam-methyl and Cloransulam in Soil by Capillary Gas Chromatography with Mass Selective 

Detection: (Final Report): Lab Project Number: RES95068: GRM 95.10. Unpublished study prepared by 

DowElanco. 53 p. 

46161601 Carver, L.; van Wesenbeeck, I.; Dolder, S. (2003) Prospective Ground-Water Monitoring Study for 

Cloransulam-methyl: Final Report. Project Number: ENV98032, 369/02, 369/03. Unpublished study 
-44 of 85-

prepared by Analytical Bio-Chemistry Labs, Inc., Crop Management Strategies, Inc., and Agsearch. 

2285 p.

43668933 Cleveland, C. (1995) Environmental Fate Summary for Cloransulam-Methyl (DE-565): Lab Project 

Number: GH-C 3629. Unpublished study prepared by DowElanco. 40 p. 

SUBMITTED EFFECTS STUDIES:

MRID: Citation:

43003407 Campbell, S.; Lynn, S. (1991) XDE-565 Herbicide: An Acute Oral Toxicity Study with the Northern 

Bobwhite: Lab Project Number: ES-DR-0314-2107-3: 103-362. Unpublished study prepared by Wildlife 

International Ltd. 21 p. 

43003408 Grimes, J.; Lynn, S.; Smith, G. (1991) XDE-565 Herbicide: A Dietary LC50 Study with the Mallard: 

Lab Project Number: ES-DR-0314-2107-2: 103-361A. Unpublished study prepared by Wildlife 

International Ltd. 21 p. 

43003409 Grimes, J.; Lynn, S.; Smith, G. (1991) XDE-565 Herbicide: A Dietary LC50 Study with the Northern 

Bobwhite: Lab Project Number: ES-DR-0314-2107-1: 103-360A. Unpublished study prepared by 

Wildlife International Ltd. 21 p. 

43668905 Beavers, J.; Foster, J.; Ross, T.; et al. (1995) XDE-565 Herbicide: A Reproduction Study with the 

Northern Bobwhite (Colinus virginianus): Lab Project Number: 103-374: DECO-ES-2514. Unpublished 

study prepared by Wildlife International Ltd. 156 p. 

43699301 Beavers, J.; Foster, J.; Ross, T.; et al. (1995) XDE-565 Herbicide: A Reproduction Study with the 

Mallard (Anas platyrhynchos): Lab Project Number: 103-375: DECO-ES-2513. Unpublished study 

prepared by Wildlife International Ltd. 153 p. 

43003410 Gorzinski, S.; Rick, D.; Richardson, C. (1991) XDE-565 Herbicide: Acute Toxicity to the Rainbow 

Trout, Oncorhynchus mykiss Walbaum: Lab Project Number: ES-DR-0314-2107-6. Unpublished study 

prepared by Dow Chemical Co. 29 p. 

43003411 Gorzinski, S.; Rick, D.; Richardson, C. (1991) XDE-565 Herbicide: Acute Toxicity to the Bluegill, 

Lepomis macrochirus Rafinesque: Lab Project Number: ES-DR-0314-2107-5. Unpublished study 

prepared by Dow Chemical Co. 29 p. 

43003412 Milazzo, D.; Servinski, M. (1991) XDE-565 Herbicide: Acute Toxicity to the Daphnid, Daphnia magna 

Straus: Lab Project Number: ES-DR-0314-2107-8. Unpublished study prepared by Dow Chemical Co. 

27 p. 

43718901 Ward, T.; Maguzu, J.; Boeri, R. (1992) Acute Toxicity of XDE-565 Herbicide to the Silverside, Menidia 

beryllina: Lab Project Number: 54-DO: ES-2495. Unpublished study prepared by T.R. Wilbury Labs, 

Inc. 23 p. 

43718902 Ward, T.; Magazu, J.; Boeri, R. (1993) Acute Flow-Through Mollusc Shell Deposition Test with XDE565 Herbicide: Lab Project Number: 53-DO: ES-2496. Unpublished study prepared by T.R. Wilbury 

Labs, Inc. 23 p. 

43718903 Ward, T.; Magazu, J.; Boeri, R. (1992) Acute Toxicity of XDE-565 Herbicide to the Grass Shrimp, 

Palaemonetes pugio: Lab Project Number: 52-DO: ES-2494. Unpublished study prepared by T.R. 

Wilbury Labs, Inc. 23 p. 

43003413 Cosse, P.; Berdasco, N. (1992) XDE-565: Acute Oral Toxicity Study in Fischer 344 Rats: Lab Project 

Number: DR-0314-2107-011A. Unpublished study prepared by Dow Chemical Co. 28 p. 

43003419 Gilbert, K.; McGuirk, R. (1993) NAF-75: Acute Oral Toxicity Study in Fischer 344 Rats: Lab Project 
-45 of 85-

Number: DR-0339-1206-001A. Unpublished study prepared by Dow Chemical Co. 29 p. 

45388202 Freeman, C.; Scubelek, S. (2001) Gauntlet 70 DF Acute Oral Toxicity Study in Rats: Lab Project 

Number: A2000-5316. Unpublished study prepared by FMC Corporation. 22 p. {OPPTS 870.1100} 

44744516 Porch, J.; Krueger, H.; McCormick, R. (1999) Effect of Three Metabolites of Cloransulam-methyl on the 

Emergence and Vegetative Vigor of Non-Target Terrestrial Plants (Tier I/II): Lab Project Number: 379-

101: ENV98050. Unpublished study prepared by Wildlife International Ltd. 281 p. {850.4100, 

850.4225} 

43715404 Schwab, D. (1995) Evaluating the Effects of XDE-565 on the Seedling Emergence and Vegetative Vigor 

of Non-Target Terrestrial Plants: Lab Project Numbers: 41706: RES94064. Unpublished study prepared 

by DowElanco. 148 p. 

44744516 Porch, J.; Krueger, H.; McCormick, R. (1999) Effect of Three Metabolites of Cloransulam-methyl on the 

Emergence and Vegetative Vigor of Non-Target Terrestrial Plants (Tier I/II): Lab Project Number: 379-

101: ENV98050. Unpublished study prepared by Wildlife International Ltd. 281 p. {850.4100, 

850.4225} 

43668916 Milazzo, D.; Servinski, M.; Weinberg, J.; et al. (1994) XDE-565 Herbicide: The Toxicity to the Aquatic 

Plant, Duckweed, Lemna gibba L. G-3: Lab Project Number: DECO-ES-2582. Unpublished study 

prepared by The Dow Chemical Co. 33 p. 

43668917 Milazzo, D.; Massaro, L.; Kirk, H.; et al. (1995) XDE-565 Acid: the Toxicity to the Green Alga, 

Selenastrum capricornutum Printz: Lab Project Number: DECO-ES-2906. Unpublished study prepared 

by The Dow Chemical Co. 31 p. 

43760003 Massaro, L.; Milazzo, D. (1995) 5-Hydroxy-DE-565: Evaluation of the Toxicity to the Green Alga, 

Selenastrum capricornutum Printz: Lab Project Number: DECO-ES-2971. Unpublished study prepared 

by The Dow Chemical Co. 11 p. 

43760004 Massaro, L.; Milazzo, D. (1995) 5-Hydroxy-DE-565 Acid: Evaluation of the Toxicity to the Green Alga, 

Selenastrum capricornutum Printz: Lab Project Number: DECO-ES-2972. Unpublished study prepared 

by The Dow Chemical Co. 10 p. 

44744501 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 

Exposed Bluegreen Alga, Anabaena flos-aquae: Lab Project Number: 981109. Unpublished study 

prepared by The Dow Chemical Company. 36 p. 

44744502 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 

Exposed Freshwater Diatom, Navicula pelliculosa: Lab Project Number: 981104. Unpublished study 

prepared by The Dow Chemical Company. 35 p. 

44744503 Kirk, H.; Gilles, M.; Hugo, J. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Exposed 

Saltwater Diatom, Skeletonema costatum: Lab Project Number: 981105. Unpublished study prepared by 

The Dow Chemical Company. 33 p. 

44744504 Kirk, H.; Gilles, M.; Rick, D. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 

Exposed Freshwater Green Alga, Selenastrum capricornutum Printz: Lab Project Number: 981110. 

Unpublished study prepared by The Dow Chemical Company. 36 p. 

44744505 Kirk, H.; Gilles, M.; Rick, D. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 

Exposed Aquatic Plant, Duckweed, Lemna gibba L. G-3: Lab Project Number: 981106. Unpublished 

study prepared by The Dow Chemical Company. 38 p. 

44744506 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Acid 

Exposed Bluegreen Alga, Anabaena flos-aquae: Lab Project Number: 981078. Unpublished study 

prepared by The Dow Chemical Company. 36 p. 

44744507 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Acid 
-46 of 85-

Exposed Freshwater Diatom, Navicula pelliculosa: Lab Project Number: 981075. Unpublished study 

prepared by The Dow Chemical Company. 35 p. 

44744508 Kirk, H.; Gilles, M.; Hugo, J. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Acid 

Exposed Saltwater Diatom, Skeletonema costatum: Lab Project Number: 981077. Unpublished study 

prepared by The Dow Chemical Company. 33 p. 

44744509 Kirk, H.; Gilles, M.; Rick, D. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Acid 

Exposed Freshwater Green Alga, Selenastrum capricornutum Printz: Lab Project Number: 981076. 

Unpublished study prepared by The Dow Chemical Company. 37 p. 

44744510 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of 5-Hydroxy-DE-565 Acid 

Exposed Aquatic Plant, Duckweed, Lemna gibba L. G-3: Lab Project Number: 981074. Unpublished 

study prepared by The Dow Chemical Company. 38 p. 

44744511 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of DE-565 Acid Exposed Blue 

Green Alga, Anabaena flos-aquae: Lab Project Number: 981031. Unpublished study prepared by The 

Dow Chemical Company. 36 p. 

44744512 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of DE-565 Acid Exposed 

Freshwater Diatom, Navicula pelliculosa: Lab Project Number: 981028. Unpublished study prepared by 

The Dow Chemical Company. 35 p. 

44744513 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of DE-565 Acid Exposed 

Saltwater Diatom, Skeletonema costatum: Lab Project Number: 981029. Unpublished study prepared by 

The Dow Chemical Company. 33 p. 

44744514 Milazzo, D.; Massaro, L.; Kirk, H. (1995) XDE-565 Acid: The Toxicity to the Green Alga, Selenastrum 

capricornutum Printz: Lab Project Number: DECO-ES-2906. Unpublished study prepared by The Dow 

Chemical Company. 31 p. 

44744515 Kirk, H.; Gilles, M.; Hugo, J. et al. (1998) Phytotoxicological Evaluation of DE-565 Acid Exposed 

Aquatic Plant, Duckweed, Lemna gibba L. G-3: Lab Project Number: 981030. Unpublished study 

prepared by The Dow Chemical Company. 38 p. 

44744517 Kirk, H.; Hugo, J.; McFadden, L. (1997) Phytotoxicological Evaluation of XDE-565 (NAF-75 

Formulation) with a Freshwater Green Algae, Selenastrum capricornutum: Lab Project Number: 971123. 

Unpublished study prepared by The Dow Chemical Company. 44 p. 

43003431 Lynn, S.; Hoxter, K. (1991) XDE-565 Herbicide: An Acute Contact Toxicity Study with the Honey Bee: 

Lab Project Number: ES-DR-0314-2107-4: 103-363A. Unpublished study prepared by Wildlife 

International, Ltd. 18 p. 
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APPENDIX A: Registered Uses and Application Rates for Cloransulam-methyl.

USE PRODUCT MAX SINGLE 

APPL. RATE

(lbs a.i./A)

MAX APPL. 

RATE PER 

CROP CYCLE 

(CC) OR YEAR

Soybeans Riverdale 565 Selective 

Herbicide 0.039 0.055 lbs ai/A/yr

Gauntlet (First Rate) 0.039 0.039 lbs ai/A/cc

Authority First DF 

Herbicide 0.040 0.055 lbs ai/A/cc

Gauntlet 70 WP 

Herbicide 0.040 0.040 lbs ai/A/cc

Gangster Herbicide 0.032 0.032 lbs ai/A/cc

FirstRate Herbicide 0.039 0.055 lbs ai/A/yr

Frontrow Herbicide 0.018 0.055 lbs ai/A/cc

Table 1: Riverdale 565 Selective Herbicide

Table 2: Gauntlet (FirstRate)

Table 3: Authority First DF Herbicide
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Table 4: Gauntlet 70 WP Herbicide
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Table 5: Gangster Herbicide
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-51 of 85-

Table 6: FirstRate Herbicide

Table 7: Frontrow Herbicide
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APPENDIX B. Major Environmental Degradates of Cloransulam-methyl.

Table B.1. Chemical Names, Structures, and Maximum Reported Amounts of Cloransulam-methyl’s Major Degradates.

Code Name/ 

Synonym Chemical NameA Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

PARENT

Cloransulam

-methyl

IUPAC: methyl 3-chloro-N-(5-ethoxy-7-

fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-

ylsulfonyl)anthranilate

CAS: methyl 3-chloro-2-[[(5-ethoxy-7-

fluoro[1,2,4]triazolo[1,5-c]pyrimidin-2-

yl)sulfonyl]amino]benzoate

CAS-no: 147150-35-4

Formula: C15H13ClFN5O5S

MW: 

MAJOR (>10%) DEGRADATES

Cloransulam

Formula: C14H11ClFN5O5S

MW: NA

Aerobic Soil Metab 43003433 37 (28) 10 (357)

Anaerobic Aquatic 

Metab 43715403 36 (28) ND (365)

5-OHcloransulam

NA

Aerobic Soil Metab 43003433 16 (28) 2 (357)

Anaerobic Aquatic 

Metab 43715403 22 (273) 1.8 (365)
-53 of 85-

Code Name/ 

Synonym Chemical NameA Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

5-OHcloransulammethyl

NA

Aerobic Soil Metab 43003433 17 (14) 1 (357)

Hydrolysis 43003432

5.8 (termination 

of study, day 

30)

5.8 (30)

Cloransulam

-methyl 

fluorethenyl

Name: N-(2-carbo~p~yZ-6-chloro)-[Inzethyl-5-(2-$uo~oethe~2~.y4~-- i~

triazolo-3-sulfonamide

Anaerobic Aquatic 

Metab 47315403 66 (365)

66 

(termination of 

study)

Sulfonic acid 

(TSPA)

NA

Soil Photolysis 43760001 22 (termination 

of study) 22

Sulfinic acid NA

NA Aqueous Photolysis 43715402 23 (termination 

of study) 23

Cloransulam

-methyl 

imidate

Chemical Name: N-(2-carbomethoxy-6-

chlorophenyl )-2-N-ethyl imido-3-

(1,2,4)-triazoloacetic acid-5-sulfonamide

Hydrolysis 43003432 29 (3) 20 (7)
-54 of 85-

Code Name/ 

Synonym Chemical NameA Chemical Structure Study Type MRID Maximum %AR (day)

Final %AR 

(study length)

Cloransulam

-methyl 

acetic acid

Chemical Name: N - (2-carbomethoxy-6-

chl orophenyl )-3-(1,2,4)-triazoloacetic 

acid-5-sulfonamide

Hydrolysis 43003432

54 (study 

termination, day 

7)

54 (7)

CO2

--

O=C=O Aerobic Soil Metab 43003433 10 10

A. IUPAC and CAS chemical names were sourced from the Compendium of Pesticide Common Names (Copyright © 1995–2009 Alan Wood). Online at: 

http://www.alanwood.net/pesticides/
-55 of 85-

APPENDIX C: ECOTOX Open Literature Studies for Cloransulam-methyl

Acceptable for EcoTox and OPP

Nelson, K. A. (2000). Soybean [Glycine max (L.) Merr] Growth and Development, White Mold [Sclerotinia 

sclerotiorum (Lib.) de Bary] Incidence, and Yellow Nutsedge (Cyperus esculentus L.) Control as Affected 

by Glyphosate and Other Herbicides. Ph.D Thesis, Michigan State Univ.,MI 279 p. (UMI# 9971967).

EcoReference No.: 120063

Chemical of Concern: GFS,HSF,IZP,NHSO4,CRM,IZX,CLNS,GYP,THF,LCF,SFZ,RIM,SXD,PTB; 

Habitat: T; Code: LITE EVAL CODED(CLNS),NO 

MIXTURE(NHSO4,THF,SXP),OK(CRM,IZP,PTB,GFS,GYP).

Acceptable for EcoTox but not OPP

Lewer, P., Finney-Brink, K. L., and Duebelbeis, D. O. (2000). Nature of the Residue of [14C]Cloransulam-Methyl 

in Lactating Goats. J.Agric.Food Chem. 48: 2532-2546.

EcoReference No.: 120081

Chemical of Concern: CLNSM; Habitat: T; Effect Codes: ACC; Code: NO ENDPOINT(CLNSM).

Smith, D. A. and Hallett, S. G. (2006). Interactions Between Chemical Herbicides and the Candidate Bioherbicide 

Microsphaeropsis amaranthi. Weed Sci. 54: 532-537 .

EcoReference No.: 119975

Chemical of Concern: ACF,MBZ,GFS,PAQT,PMSM,CFE,ATZ,GIB,CLNS,GYP,BMN,LCF,IZT; 

Habitat: T; Effect Codes: POP; Code: NO 

CONC(ATZ,CLNS,CFE,LCF,PAQT,GFS,MBZ),TARGET(GYP).

Excluded

1997). Cloransulam-methyl; pesticide tolerances. Fed. Regist. 62: 49158-49163.

Chem Codes: Chemical of Concern: CLNSM Code: FOOD.

Pesticide Fact Sheet: Cloransulam-Methyl. Govt Reports Announcements & Index (GRA&I), Issue 06, 1998 .

Chem Codes: Chemical of Concern: CLNS Code: REVIEW.

Abu-Farha, M., Niles, J., and Willmore, W. G. (2005). Erythroid-Specific 5-Aminolevulinate Synthase Protein Is 

Stabilized by Low Oxygen and Proteasomal Inhibition. Biochem Cell Biol Biochemistry and cell biology 

= Biochimie et biologie cellulaire 83: 620-30.

Chem Codes: Chemical of Concern: CLNS Code: HUMAN HEALTH,IN VITRO.

Akiyama, Yumi, Matsuoka, Tomofumi, and Mitsuhashi, Takao (2009). Multi-residue screening method of acidic 

pesticides in agricultural products by liquid chromatography/time of flight mass spectrometry. J. Pestic. 

Sci. (Tokyo, Jpn.) 34: 265-272.

Chem Codes: Chemical of Concern: CLNS Code: CHEM METHODS.

Alikhanidi, Sokratis and Takahashi, Yoshimasa (2004). Pesticide persistence in the environment - collected data and 

structure-based analysis. J. Comput. Chem., Jpn. 3: 59-70.

Chem Codes: Chemical of Concern: CLNS Code: FATE.

Anon (2002). 2-(2,2-difluoroethoxy)-6-trifluoromethyl-N-(5,8-dimethoxy[1,2,4]t riazolo [1,5-c]pyrimidin-2-

yl)benzenesulfonamide and its use as a herbicide in mixtures. Res. Discl. 462: P1832-P1833.

Chem Codes: Chemical of Concern: CLNSM,PXS Code: MIXTURE.
-56 of 85-

Anon (2002). N-(5,7-dimethoxy[1,2,4]triazolo[1,5-a]pyrimidin-2-yl)arylsulfonamide compounds and their use as 

herbicides in mixtures. Res. Discl. 459: 1230-1231.

Chem Codes: Chemical of Concern: CLNS Code: REVIEW.

Bergman, A. M., Munch-Petersen, B., Jensen, P. B., Sehested, M., Veerman, G., Voorn, D. A. , Smid, K., Pinedo, 

H. M., and Peters, G. J. ( 2001). Collateral Sensitivity to Gemcitabine (2',2'-Difluorodeoxycytidine) and 

Cytosine Arabinoside of Daunorubicin- and Vm-26-Resistant Variants of Human Small Cell Lung Cancer 

Cell Lines. Biochem Pharmacol Biochemical pharmacology 61: 1401-8.

Chem Codes: Chemical of Concern: CLNS Code: HUMAN HEALTH.

Camaioni, D. M., Samuels, W. D., Linehan, J. C., Sharma, A. K., and Hogan, M. O. ( Organic Tanks Safety 

Program, Fy97 Waste Aging Studies. Revision 1. Govt Reports Announcements & Index (GRA&I), Issue 

08, 1999.

Chem Codes: Chemical of Concern: CLNS Code: FATE.

Cupples, Alison M., Sims, Gerald K., Hultgren, Ryan P., and Hart, Steven E (2000). Effect of soil conditions on the 

degradation of cloransulam-methyl. J. Environ. Qual. 29: 786-794 .

Chem Codes: Chemical of Concern: CLNS Code: BACTERIA,FATE.

Del Carmen Vila M, Aldonatti, C., and San Martin De Viale Lc ( Evaluation of the Porphyrinogenic Ability of 

Lindane in Rats. ACTA PHYSIOL PHARMACOL LATINOAM; 36 (1). 1986. 69-76.

Chem Codes: Chemical of Concern: CLNS,HCCH Code: NON-ENGLISH .

Fortin, J., Flury, M., Jury, W. A., and Streck, T. ( Rate-Limited Sorption of Simazine in Saturated Soil Columns.

JOURNAL OF CONTAMINANT HYDROLOGY; 25 (3-4). 1997. 219-234.

Chem Codes: Chemical of Concern: CLNS,SZ Code: FATE.

Herman, Rod A. and Scherer, Peter N (2006). Fit of four curve-linear models to decay profiles for pest control 

substances in soil. J. Agric. Food Chem. 54: 4343-4349.

Chem Codes: Chemical of Concern: CLNS Code: FATE.

Hernandez-Borges, Javier, Garcia-Montelongo, Francisco J., Cifuentes, Alejandro, and Rodriguez-Delgado, Miguel 

Angel (2005). Analysis of triazolopyrimidine herbicides in soils using field-enhanced sample injectioncoelectroosmotic capillary electrophoresis combined with solid-phase extraction. J. Chromatogr., A 1100: 

236-242.

Chem Codes: Chemical of Concern: CLNSM Code: CHEM METHODS.

Hernandez-Borges, Javier, Garcia-Montelongo, Francisco J., Cifuentes, Alejandro, and Rodriguez-Delgado, Miguel 

Angel (2005). Determination of herbicides in mineral and stagnant waters at ng/L levels using capillary 

electrophoresis and UV detection combined with solid-phase extraction and sample stacking. J. 

Chromatogr., A 1070: 171-177.

Chem Codes: Chemical of Concern: CLNSM Code: CHEM METHODS.

Hernandez-Borges, Javier, Rodriguez-Delgado, Miguel Angel, Garcia-Montelongo, Francisco J., and Cifuentes, 

Alejandro (2005). Analysis of pesticides in soy milk combining solid-phase extraction and capillary 

electrophoresis-mass spectrometry. J. Sep. Sci. 28: 948-956.

Chem Codes: Chemical of Concern: CLNS Code: CHEM METHODS.

Ibsen, T. G. ( Lims Strategy Review. Govt Reports Announcements & Index (GRA&I), Issue 20, 1995.

Chem Codes: Chemical of Concern: CLNS Code: CHEM METHODS/REVIEW.

Igoryanova, N. A., Shukhnov, A. F., Spirichev, V. B., Ivanov, A. A., Fadina, I. V., Guseva, L. I., Meandrova, S. B., 

and Shatnyuk, L. N. ( Enrichment of High and First-Rate Wheat's Flour With Vitamins and Mineral 

Substances. VOPROSY PITANIYA; 0 (5). 1994. 5-8.

Chem Codes: Chemical of Concern: CLNS Code: NON-ENGLISH,HUMAN HEALTH.
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Johnson, Timothy C (2006 ). The Discovery of Florasulam and Penoxsulam Herbicides. CRM-089.

Chem Codes: Chemical of Concern: CLNS Code: ABSTRACT.

Johnson, Timothy C., Martin, Timothy P., Mann, Richard K., and Pobanz, Mark A (2009). Penoxsulam - structureactivity relationships of triazolopyrimidine sulfonamides. Bioorg. Med. Chem. 17: 4230-4240.

Chem Codes: Chemical of Concern: CLNSM Code: REVIEW.

Kochelaev, V. A., Gaĭ, Sin, N. K., and Sviridiuk, A. I. ( [Providing Safe Work Conditions in Jsc 

&Quot;Uralasbest&Quot;]. Med Tr Prom Ekol. 2008(3):37-42. [Meditsina truda i promyshlennaia 

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Chem Codes: Chemical of Concern: CLNS Code: NON-ENGLISH,HUMAN HEALTH.

Krieger, M. S., Wynn, J. L., and Yoder, R. N (2000). Extraction of cloransulam-methyl from soil with subcritical 

water and supercritical CO2. J. Chromatogr., A 897: 405-413.

Chem Codes: Chemical of Concern: CLNSM Code: CHEM METHODS.

Krieger, Mark, Yoder, Robin, Stafford, Les, Batzer, Fred, Smith, Joelene, Cook, Wendi, and Lewer, Paul (2000). 

Environmental fate and metabolism of the sulfonamide herbicides diclosulam and cloransulam-methyl .

AGRO-090.

Chem Codes: Chemical of Concern: CLNSM Code: FATE.

Kusell, M., Lake, L., Andersson, M., and Gerschenson, L. E. (1978). Cellular and Molecular Toxicology of Lead. Ii. 

Effect of Lead on Delta-Aminolevulinic Acid Synthetase of Cultured Cells. J Toxicol Environ Health 4: 

:515-25.

Chem Codes: Chemical of Concern: CLNS,PbN Code: IN VITRO.

Lehotay, S. J. ( Supercritical Fluid Extraction of Pesticides in Foods. JOURNAL OF CHROMATOGRAPHY A; 785 

(1-2). 1997. 289-312.

Chem Codes: Chemical of Concern: CLNS Code: CHEM METHODS.

Liao, Quan, Yao, Jianhua, and Yuan, Shengang (2007). Prediction of mutagenic toxicity by combination of 

Recursive Partitioning and Support Vector Machines. Mol. Diversity 11: 59-72.

Chem Codes: Chemical of Concern: CLNS Code: MODELING,REVIEW.

Löwkvist, B., Oredsson, S. M., Holm, I., Emanuelsson, H., and Heby, O. (1987). Inhibition of Polyamine Synthesis 

Reduces the Growth Rate and Delays the Expression of Differentiated Phenotypes in Primary Cultures of 

Embryonic Mesoderm From Chick. Cell Tissue Res 249: :151-60.

Chem Codes: Chemical of Concern: CLNS Code: IN VITRO.

Paulson, B. K., Porter, T. J., and Kent, C. (1989). The Effect of Polycyclic Aromatic Hydrocarbons on Choline 

Kinase Activity in Mouse Hepatoma Cells. Biochim Biophys Acta 1004: :274-7.

Chem Codes: Chemical of Concern: CLNS,PAH Code: IN VITRO.

Premi, P. R. and Cornfield, A. H. (1969). Effects of Addition of Copper, Manganese, Zinc and Chromium 

Compounds on Ammonification and Nitrification During Incubation of Soil. Plant Soil 31: 345-352.

Chem Codes: Chemical of Concern: CaSO4,CrS,CuS,ZnS,MnSO4 Code: NO SPECIES.

Rodriguez-Delgado, Miguel Angel and Hernandez-Borges, Javier (2007). Rapid analysis of triazolopyrimidine 

sulfoanilide herbicides in waters and soils by high-performance liquid chromatography with UV detection 

using a C18 monolithic column. J. Sep. Sci. 30: 8-14.

Chem Codes: Chemical of Concern: CLNSM Code: CHEM METHODS.

Roth, Gary A (1995). Synthesis of Cysteine and Homoglutathione Conjugates of Crop Protection Agents Containing 

Electrophilic Centers. J. Org. Chem. 60: 8105-9.

Chem Codes: Chemical of Concern: CLNS Code: CHEM METHODS.
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Sampedro, M. A., Blanco, A., Llama, M. J., and Serra, J. L. (1995). Sorption of Heavy Metals to Phormidium 

Laminosum Biomass. Biotechnol.Appl.Biochem. 22: 355-366.

Chem Codes: Chemical of Concern: CuS,ZnS,FeS,CrS,NiS,CdCl,PbN Code: NO SPECIES.

Scrano, L., Bufo, S. A., Cataldi, T. R., and Albanis, T. A. (2004). Surface Retention and Photochemical Reactivity 

of the Diphenylether Herbicide Oxyfluorfen. J Environ Qual Journal of environmental quality 33: 605-

11. 

Chem Codes: Chemical of Concern: CLNS,OXF Code: FATE.

Shackelford, Darcy D., Duebelbeis, Dennis O., and Snell, Brian E (1996). Determination of Residues of 

Cloransulam-methyl in Soybeans and Soybean Forage, Hay, and Processed Commodities by Capillary Gas 

Chromatography with Mass Spectrometric Detection. J. Agric. Food Chem. 44: 3570-3575.

Chem Codes: Chemical of Concern: CLNSM Code: CHEM METHODS.

Shareef, A., Egerer, S., and Kookana, R. (2009). Effect of Triclosan and Triclocarban Biocides on Biodegradation of 

Estrogens in Soils. Chemosphere 77: :1381-6.

Chem Codes: Chemical of Concern: CLNS Code: BACTERIA,FATE.

Shi, S., Hudson, F. N., Botta, D., Mcgrath, M. B., White, C. C., Neff-Laford, H. D., Dabrowski, M. J., Singh, N. P., 

and Kavanagh, T. J. (2007). Over Expression of Glutamate Cysteine Ligase Increases Cellular Resistance 

to H2o2-Induced Dna Single-Strand Breaks. Cytometry A 71: 686-92.

Chem Codes: Chemical of Concern: CLNS,HOX Code: IN VITRO.

Shier, W. T. (1979). Activation of High Levels of Endogenous Phospholipase A2 in Cultured Cells. Proc Natl Acad 

Sci U S A 76: :195-9.

Chem Codes: Chemical of Concern: CLNS Code: IN VITRO.

Sims, G. K (2006). Nitrogen starvation promotes biodegradation of N-heterocyclic compounds in soil. Soil Biol. 

Biochem. 38: 2478-2480.

Chem Codes: Chemical of Concern: CLNSM,ATZ Code: BACTERIA,FATE.

Sims, Gerald K. and Cupples, Alison M (1999). Factors controlling degradation of pesticides in soil. Pestic. Sci. 55: 

598-601.

Chem Codes: Chemical of Concern: CLNSM,ATZ Code: FATE.

Stoner, G. D. (1991). Lung Tumors in Strain a Mice as a Bioassay for Carcinogenicity of Environmental Chemicals.

Exp.Lung Res. 17: 405-423.

Chem Codes: Chemical of Concern: 

BAP,PAH,DMBA,NSA,CH3I,CF,4CE,MnSO4,CrS,CIN,MEN,MAT,MSC,SAC,VNL,DNT Code: REFS 

CHECKED/REVIEW.

Tarasov, V. A., Abilev, S. K., Velibekov, R. M., and Aslanyan, M. M. (2003). Efficiency of Batteries of Tests for 

Estimating Potential Mutagenicity of Chemicals. Russ.J.Genet.(Translation of Genetika (Moscow Russian 

Federation)) 39: 1191-1200.

Chem Codes: Chemical of Concern: 

ACD,PAH,BZD,DDT,Captan,NaNO3,PCP,THM,CHR,Ziram,ETHN,ETO,ACY,BMY,DMT,Cd,CdCl,TPE

,MP,MOR,As,PRN,PCB,SAC,FML,CrS,CrCl3 Code: REFS CHECKED/REVIEW.

van Wesenbeeck, I. J. and Havens, P. L. (1999). A Groundwater Exposure Assessment for Cloransulam-Methyl in 

the U.s. Soybean Market. Journal of Environmental Quality [J. Environ. Qual.]. Vol. 28, no. 2, pp. 513-

522. Mar-Apr 1999. 28: 513-522.

Chem Codes: Chemical of Concern: CLNSM Code: FATE,MODELING,REVIEW.

van Wesenbeeck, I. J., Zabik, J. M., Wolt, J. D. , Bormett, G. A., and Roberts, D. W (1997). Field dissipation of 

cloransulam-methyl at two sites in the US soybean market. AGRO-075.
-59 of 85-

Chem Codes: Chemical of Concern: CLNSM Code: FATE.

van Wesenbeeck, Ian, Carver, Les, Cartron, Juliet, Brandt, Jodi, and Snyder, Nathan (2000). Comparison of tracer 

and herbicide leaching using pipe lysimeters and porous cup lysimeters. AGRO-131.

Chem Codes: Chemical of Concern: CLNS Code: FATE.

Van Wesenbeeck, Ian J. and Havens, Patrick L (1999). Water quality: a groundwater exposure assessment for 

cloransulam-methyl in the U.S. soybean market. J. Environ. Qual. 28: 513-522.

Chem Codes: Chemical of Concern: CLNS Code: MODELING,REVIEW.

van Wesenbeeck, Ian J., Zabik, John M., Wolt, Jeffrey D., Bormett, Gary A., and Roberts, David W (1997). Field 

dissipation of cloransulam-methyl at four sites in the U.S. soybean market. J. Agric. Food Chem. 45: 3299-

3307.

Chem Codes: Chemical of Concern: CLNSM Code: FATE.

Wallace, A., Romney, E. M., and Patel, P. M. (1978). Role of Synthetic Chelating Agents in Trace Metal Uptake by 

Plants. In: D.C.Adriano and I.L.Brisbin,Jr.(Eds.), Environmental Chemistry and Cycling Processes, 

Proc.Symp.Held at Augusta, Georgia, April 18-May 1, 1976, Tech.Info.Center, U.S.Dep of Energy 

(U.S.NTIS CONF-760429) 645-657.

Chem Codes: Chemical of Concern: Pb,CrS,CdS,Ni,Co Code: REFS CHECKED/REVIEW.

Whiteside, Melanie, Mineau, Pierre, Morrison, Clare, and Knopper, Loren D (2008). Comparison of a score-based 

approach with risk-based ranking of in-use agricultural pesticides in Canada to aquatic receptors. Integr. 

Environ. Assess. Manage. 4: 215-236.

Chem Codes: Chemical of Concern: CLNS Code: REVIEW.

Wolt, Jeffrey D., Smith, Joelene K., Sims, Jerry K., and Duebelbeis, Dennis O (1996). Products and kinetics of 

cloransulam-methyl aerobic soil metabolism. J. Agric. Food Chem. 44: 324-32.

Chem Codes: Chemical of Concern: CLNSM Code: FATE.

Yeh, C. K. and Novak, J. T. ( Anaerobic Biodegradation of Gasoline Oxygenates in Soils. WATER 

ENVIRONMENT RESEARCH; 66 (5). 1994. 744-752.

Chem Codes: Chemical of Concern: CLNS Code: BACTERIA,FATE.

Zabik, J. M., Ostrander, J. A., Roberts, D. W., and Thompson, G. D (1996). Assessing the dissipation of 14C 

cloransulam-methyl under field conditions. AGRO-015.

Chem Codes: Chemical of Concern: CLNSM Code: FATE.

Zabik, J. M. Ostrander J. A., Roberts, D. W., and Thompson, G. D. ( Assessing the Dissipation of 14c CloransulamMethyl Under Field Conditions . 211TH AMERICAN CHEMICAL SOCIETY NATIONAL MEETING, NEW 

ORLEANS, LOUISIANA, USA, MARCH 24-28, 1996. ABSTRACTS OF PAPERS AMERICAN CHEMICAL 

SOCIETY; 211 (1-2). 1996. AGRO 15.

Chem Codes : Chemical of Concern: CLNS Code: FATE.

Zhang, N. and Casida, J. E. (2002). Novel Irreversible Butyrylcholinesterase Inhibitors: 2-Chloro-1-(SubstitutedPhenyl)Ethylphosphonic Acids. Bioorg Med Chem Bioorganic & medicinal chemistry 10: 1281-90.

Chem Codes: Chemical of Concern: CLNS,EPH Code: CHEM METHODS,IN VITRO.

Target: Toxicity of Chemical on Intended Pest

Al-Khatib, Kassim, Peterson, Dallas E., and Regehr, David L (2000). Control of imazethapyr-resistant common 

sunflower (Helianthus annuus) in soybean (Glycine max) and corn (Zea mays). Weed Technol. 14: 133-

139.

Chemical of Concern: CLNS,IZT,CRM,GYP,ATZ; Habitat: T; Code: TARGET(CLNS).
-60 of 85-

Allen, Jayla R., Johnson, William G., Smeda, Reid J., Wiebold, William J., and Massey, Raymond E (2001). 

Management of acetolactate synthase (ALS)-resistant common sunflower (Helianthus annuus L.) in 

soybean (Glycine max). Weed Technol. 15: 571-575.

Chemical of Concern: CLNS,IZT,CRM,IZQ,IZX; Habitat: T; Code: TARGET(CLNS).

Armel Gregory R., Richardson Robert J., Wilson Henry P., Trader Brian W., Whaley Cory M., Hines Thomas E., 

Armel Gregory R., Richardson Robert J., Trader Brian W., Whaley Cory M., Wilson Henry P., Hines 

Thomas E., Armel Gregory R., Richardson Robert J., Trader Brian W., and Whaley Cory M. (2009). 

Evaluation of Acetolactate Synthase-Inhibiting Herbicides for Weed Control in Transplanted Bell Pepper. 

HortTechnology, vol. 19, no. 2, pp. 400-404, 2009.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Ashigh, Jamshid and Tardif, Francois J (2006). ALS-inhibitor resistance in populations of eastern black nightshade 

(Solanum ptycanthum) from Ontario. Weed Technol. 20: 308-314.

Chemical of Concern: CLNS,IZT,ATZ; Habitat: T; Code: TARGET(CLNS).

Askew, S. D., Wilcut, J. W., and Langston, V. B. (1999). Weed Management in Soybean (Glycine max) with 

Preplant-Incorporated Herbicides and Cloransulam-Methyl. Weed Technol. 13: 276-282.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Barnes, J. W. (2003). Factors Influencing Weed Control Potential of Cloransulam in Soybean (Glycine max). 

Ph.D.Thesis, Univ.of Arkansas,AK 226 p. (Order No.AADAA-I3097299).

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(FSF,CLNS).

Barnes, J. W. and Oliver, L. R. (2004). Cloransulam Absorption, Translocation, and Efficacy on Common Broadleaf 

Weed Species . Weed Sci. 52: 634-641.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Barnes, J. W. and Oliver, L. R. (2004). Preemergence Weed Control in Soybean with Cloransulam. Weed Technol.

18: 1077-1090.

Chemical of Concern: FSF,CLNS; Habitat: T; Code: TARGET(FSF,CLNS).

Barnes, Jeff W. and Oliver, Lawrence R (2004). Cloransulam antagonizes annual grass control with 

aryloxyphenoxypropionate graminicides but not cyclohexanediones. Weed Technol. 18: 763-772.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Baumgartner, Jolene R., Al-Khatib, Kassim, and Currie, Randall S (1999). Cross-resistance of imazethapyrresistant common sunflower (Helianthus annuus) to selected imidazolinone, sulfonylurea, and 

triazolopyrimidine herbicides. Weed Technol. 13: 489-493.

Chemical of Concern: CLNS,CR,IZX,THF; Habitat: T; Code: TARGET(CLNS).

Brewer, C. (2007). Arkansas glyphosate-resistant common ragweed (Ambrosia artemisiifolia). 

Chemical of Concern: CLNS,GYP,PAQT,24D,DMB,GFS; Habitat: T; Code: TARGET(CLNS).

Christoffers, Michael J., Nandula, Vijay K., Howatt, Kirk A., and Wehking, Todd R (2006). Target-site resistance to 
-61 of 85-

acetolactate synthase inhibitors in wild mustard (Sinapis arvensis). Weed Sci. 54: 191-197.

Chemical of Concern: CLNS,IZT,THF,IZX; Habitat: T; Code: TARGET(CLNS).

Corrigan, Karen A. and Harvey, R. Gordon (2000). Glyphosate with and without residual herbicides in no-till 

glyphosate-resistant soybean (Glycine max). Weed Technol. 14: 569-577.

Chemical of Concern: CLNS,GYP,IZT; Habitat: T; Code: TARGET(CLNS).

Davis, Vince M., Gibson, Kevin D., Bauman, Thomas T., Weller, Stephen C., and Johnson, William G (2009). 

Influence of weed management practices and crop rotation on glyphosate-resistant horseweed (Conyza 

canadensis) population dynamics and crop yield-years III and IV. Weed Sci. 57: 417-426.

Chemical of Concern: CLNS,RIM,ATZ,GYP,FZF,GFS; Habitat: T; Code: TARGET(CLNS).

Davis, Vince M., Kruger, Greg R., Stachler, Jeff M., Loux, Mark M., and Johnson, William G (2009). Growth and 

seed production of horseweed (Conyza canadensis) populations resistant to glyphosate, ALS-inhibiting, and 

multiple (glyphosate + ALS-inhibiting) herbicides. Weed Sci. 57: 494-504.

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Dirks, Jeremy F., Johnson, William G., Smeda, Reid J., Wiebold, William J., and Massey, Raymond E (2000). Use 

of preplant sulfentrazone in no-till, narrow-row, glyphosate-resistant Glycine max. Weed Sci. 48: 628-639.

Chemical of Concern: CLNS,SFZ; Habitat: T; Code: TARGET(CLNS).

Felix, Joel, Doohan, Douglas J., Ditmarsen, Scott C., Schultz, Marvin E., Wright, Terry R., Flood, Brian R., and 

Rabaey, Thomas L (2002). Sensitivity of sweet corn (Zea mays L.) and potatoes (Solanum tuberosum L.) to 

cloransulam-methyl soil residues. Crop Prot. 21: 763-772 .

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Fennimore, Steven A., Lanini, W. Thomas, McGiffen, Milton E., and Bell, Carl E (2000). Evaluation of low-rate 

herbicides for potential use in vegetable crops. Proc. West. Soc. Weed Sci. 53: 53-57.

Chemical of Concern: CLNS,IZX; Habitat: T; Code: TARGET(CLNS).

Franey, R. J. and Hart, S. E. (1999). Time of Application of Cloransulam for Giant Ragweed (Ambrosia trifida) 

Control in Soybean (Glycine max). Weed Technol. 13: 825-828.

Chemical of Concern: LCF,CLNS; Habitat: T; Code: TARGET (LCF,CLNS).

Franzen, D. W., O'Barr, J. H., and Zollinger, R. K (2004). Influence of certain postemergence broadleaf herbicides 

on soybean stressed from iron deficiency chlorosis. Agron. J. 96: 1357-1363.

Chemical of Concern: CLNS,IZT,THF,IZM,BT,GYP; Habitat: T; Code: TARGET(CLNS).

Gerwick, B. Clifford, Cseke, Csaba T., Deboer, Gerry, Kleschick, William A., and Schmitzer, Paul R (1996). 

Translation of in vitro activity to in vivo activity: lessons from the triazolopyrimidine sulfonanilides. Weed 

Sci. 44: 757-762.

Chemical of Concern: CLNSM; Habitat: T; Code: TARGET(CLNS).

Gonzini, Lisa C., Hart, Stephen E., and Wax, Loyd M (1999). Herbicide combinations for weed management in 

glyphosate-resistant soybean (Glycine max). Weed Technol. 13: 354-360.
-62 of 85-

Chemical of Concern: CLNSM,GYP,IZT; Habitat: T; Code: TARGET(CLNS).

Green, Jerry M., Hale, Theresa, Pagano, Margaret A., Andreassi, John L. II, and Gutteridge, Steven A (2009). 

Response of 98140 corn with gat4621 and hra transgenes to glyphosate and ALS-inhibiting herbicides. 

Weed Sci. 57: 142-148.

Chemical of Concern: CLNSM,GYP,CRM,SMU; Habitat: T; Code: TARGET(CLNS).

Grey, Timothy L., MacRae, Andrew, and Culpepper, A. Stanley (2008). Transplanted onion response to previously 

applied residual herbicides. Weed Technol. 22: 477-480.

Chemical of Concern: CLNS,DU; Habitat: T; Code: TARGET(CLNS).

Grichar, W. James (2007). Control of smellmelon (Cucumis melo) in soybean with herbicides. Weed Technol. 21: 

777-779.

Chemical of Concern: CLNS,PDM,GYP,CRM; Habitat: T; Code: TARGET(CLNS).

Griffin, Roy Matthew (2003). Weed control in early-maturing Mississippi soybean at various row spacings and 

planting dates. 

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Hanson, B. D., Park, K. W., Mallory-Smith, C. A. , and Thill, D. C (2004). Resistance of Camelina microcarpa to 

acetolactate synthase inhibiting herbicides. Weed Res. 44: 187-194.

Chemical of Concern: CLNS,IZX,MTS,CSF; Habitat: T; Code: TARGET(CLNS).

James Grichar, W., Dotray, Peter A., and Ray Langham, D (2009). Sesame (Sesamum indicum L.) response to 

preemergence herbicides. Crop Prot. 28: 928-933.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Johnson, Bryan F., Bailey, William A., Wilson, Henry P., Holshouser, David L., Herbert, D. Ames Jr., and Hines, 

Thomas E (2002). Herbicide effects on visible injury, leaf area, and yield of glyphosate-resistant soybean 

(Glycine max). Weed Technol. 16: 554-566.

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Krausz, Ronald F., Kapusta, George, and Matthews, Joseph L (1998). Sulfentrazone for weed control in soybean 

(Glycine max). Weed Technol. 12: 684-689.

Chemical of Concern: CLNS,SFZ; Habitat: T; Code: TARGET(CLNS).

Krausz, Ronald F. and Young, Bryan G (2001). Response of double-crop glyphosate-resistant soybean (Glycine 

max) to broadleaf herbicides. Weed Technol. 15: 300-305.

Chemical of Concern: CLNS,IZT,IZX,LCF; Habitat: T; Code: TARGET(CLNS).

Kruger, Greg R., Davis, Vince M., Weller, Stephen C., Stachler, J. M., Loux, M. M., and Johnson, William G 

(2009). Frequency, distribution, and characterization of horseweed (Conyza canadensis) biotypes with 

resistance to glyphosate and ALS-inhibiting herbicides. Weed Sci. 57: 652-659.

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).
-63 of 85-

Lamego, F. P., Vidal, R. A., Burgos, N. R., and Federizzi, L. C (2009). Cross-resistance of Bidens subalternans to 

acetolactate synthase inhibitors in Brazil. Weed Res. 49: 634-641.

Chemical of Concern: CLNSM,CRME,IZT; Habitat: T; Code: TARGET(CLNS).

Lamego, Fabiane P., Charlson, Dirk, Delatorre, Carla A., Burgos, Nilda R., and Vidal, Ribas A (2009). Molecular 

basis of resistance to ALS-inhibitor herbicides in greater beggarticks. Weed Sci. 57: 474-481.

Chemical of Concern: CLNS,IZT,CRM; Habitat: T; Code: TARGET(CLNS).

Legleiter, Travis R. and Bradley, Kevin W (2008). Glyphosate and multiple herbicide resistance in common 

waterhemp (Amaranthus rudis) populations from Missouri. Weed Sci. 56: 582-587.

Chemical of Concern: CLNS,GYP,THF; Habitat: T; Code: TARGET(CLNS).

Manning, Grant R. and Fennimore, Steven A (2001). Evaluation of low-rate herbicides to supplement methyl 

bromide alternative fumigants to control weeds in strawberry. HortTechnology 11: 603-609.

Chemical of Concern: CLNS,MB,NPP; Habitat: T; Code: TARGET(CLNS).

McKelvey, Robert A., Wright, John P., and Honegger, Joy L (2002). A comparison of crop and non-crop plants as 

sensitive indicator species for regulatory testing. Pest Manage. Sci. 58: 1161-1174.

Chemical of Concern: CLNSM,CZE,TFN; Habitat: T; Code: TARGET(CLNS).

Millar, Katherine, Gibson, David J., Young, Bryan G., and Wood, Andrew J (2007). Impact of interspecific 

competition on seed development and quality of five soybean cultivars. Aust. J. Exp. Agric. 47: 1455-1459.

Chemical of Concern: CLNS,MTC; Habitat: T; Code: TARGET(CLNS).

Nelson, K. A. and Renner, K. A. (1998). Postemergence Weed Control with CGA-277476 and Cloransulam-Methyl 

in Soybean (Glycine max). Weed Technol. 12: 293-299 .

EcoReference No.: 64012

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Nelson, Kelly A. and Renner, Karen A (2002). Yellow nutsedge (Cyperus esculentus) control and tuber production 

with glyphosate and ALS-inhibiting herbicides. Weed Technol. 16: 512-519.

Chemical of Concern: CLNS,GYP,IZT,RIM,IZX; Habitat: T; Code: TARGET(CLNS).

Nelson, Kelly Allan (1997). Postmergence weed control in soybean (Glycine max (L.) Merr) with imazamok, 

imazethapyr, oxasulfuron, and cloransulam-methyl. 

Chemical of Concern: CLNSM,IZT; Habitat: T; Code: TARGET(CLNS).

Norris, Justin L., Shaw, David R., and Snipes, Charles E (2001). Weed control from herbicide combinations with 

three formulations of glyphosate. Weed Technol. 15: 552-558.

Chemical of Concern: CLNS,GYP,FSF,LCF,CRM; Habitat: T; Code: TARGET(CLNS).

Olszyk, David, Pfleeger, Thomas, Lee, E. Henry, and Plocher, Milton (2010). Potato (Solanum tuberosum) 

greenhouse tuber production as an assay for asexual reproduction effects from herbicides. Environ. 

Toxicol. Chem. 29: 111-121.
-64 of 85-

Chemical of Concern: CLNS,DMB,GYP,IZP,SMU; Habitat: T; Code: TARGET(CLNS).

Patzoldt, W. L. and Tranel, P. J. (2007). Multiple ALS Mutations Confer Herbicide Resistance in Waterhemp 

(Amaranthus tuberculatus). Weed Sci. 55: 421-428.

EcoReference No.: 119504

Chemical of Concern: IZT,THF,CLNS,PTB; Habitat: T; Effect Codes: GRO,BCM; Code: 

OK(IZT,PTB),TARGET(THF,CLNS).

Patzoldt, W. L., Tranel, P. J., Alexander, A. L., and Schmitzer, P. R. (2001). A Common Ragweed Population 

Resistant to Cloransulam-Methyl. Weed Sci. 49: 485-490.

EcoReference No.: 67160

Chemical of Concern: CLNSM; Habitat: T; Code: TARGET(CLNSM).

Patzoldt, William L. and Tranel, Patrick J (2002). Molecular analysis of cloransulam resistance in a population of 

giant ragweed. Weed Sci. 50: 299-305.

Chemical of Concern: CLNS,IZT,CRM; Habitat: T; Code: TARGET(CLNS).

Patzoldt, William L. and Tranel, Patrick J (2007). Multiple ALS mutations confer herbicide resistance in waterhemp 

(Amaranthus tuberculatus). Weed Sci. 55: 421-428.

Chemical of Concern: CLNS,IZT,THF,CRM,PTB; Habitat: T; Code: TARGET(CLNS).

Payne, Scott A. and Oliver, Lawrence R (2000). Weed control programs in drilled glyphosate-resistant soybean. 

Weed Technol. 14: 413-422.

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Pfleeger, Thomas, Olszyk, David, Plocher, Milton , and Yilma, Solomon (2008). Effects of low concentrations of 

herbicides on full-season, field-grown potatoes. J. Environ. Qual. 37: 2070-2082.

Chemical of Concern: CLNSM,IZP,SMM,GYP; Habitat: T; Code: TARGET(CLNS).

Pline, W. A., Wilcut, J. W., and Edmisten, K. L. (2002). Postemergence Weed Control in Soybean (Glycine max) 

with Cloransulam-Methyl and Diphenyl Ether Tank-Mixtures. Weed Technol. 16: 737-742.

Chemical of Concern: FSF,CLNSM; Habitat: T; Code: TARGET(FSF,CLNSM).

Poston, D. H., Wu, J., Hatzios, K. K., and Wilson, H. P. (2001). Enhanced Sensitivity to Cloransulam-Methyl in 

Imidazolinone-Resistant Smooth Pigweed. Weed Sci. 49: 711-716.

EcoReference No.: 63726

Chemical of Concern: CLNSM; Habitat: T; Code: TARGET(CLNSM).

Poston, Daniel H., Nandula, Vijay K., Griffin, R. Matt, and Koger, Clifford H (2007). Texasweed (Caperonia 

palustris) control in soybean with postemergence herbicides. Weed Technol. 21: 670-673.

Chemical of Concern: CLNS,FSF,GYP; Habitat: T; Code: TARGET(CLNS).

Poston, Daniel H., Wilson, Henry P., and Hines, Thomas E (2000). Imidazolinone resistance in several Amaranthus 

hybridus populations. Weed Sci. 48: 508-513.

Chemical of Concern: CLNSM,CRM,THF; Habitat: T; Code: TARGET(CLNS).
-65 of 85-

Reddy, K. N. (2000). Weed Control in Soybean (Glycine max) with Cloransulam and Diclosulam. Weed Technol.

14: 293-297.

EcoReference No.: 59626

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Rundle, Mark F., Walters, S. Alan, and Young, Bryan G (2007). Efficacy of postemergence corn and soybean 

herbicides on volunteer horseradish (Armoracia rusticana). Weed Technol. 21: 501-505.

Chemical of Concern: CLNS,CRM,IZX,24D,IZT; Habitat: T; Code: TARGET(CLNS).

Shaw, D. R., Bennett, A. C., and Grant, D. L. (1999). Weed Control in Soybean (Glycine max) with Flumetsulam, 

Cloransulam, and Diclosulam. Weed Technol. 13: 791-798 .

EcoReference No.: 64298

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Shaw, David R. and Arnold, James C (2002). Weed control from herbicide combinations with glyphosate. Weed 

Technol. 16: 1-6.

Chemical of Concern: CLNSM,GYP; Habitat: T; Code: TARGET(CLNS).

Sikkema, Peter H., Brown, Lynette, Shropshire, Christy, Spieser, Helmut, and Soltani, Nader (2008). Flat fan and air 

induction nozzles affect soybean herbicide efficacy. Weed Biol. Manage. 8: 31-38.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Sikkema, Peter H., Soltani, Nader, Shropshire, Christy, and Cowan, Todd (2004). Tolerance of white beans to 

postemergence broadleaf herbicides. Weed Technol. 18: 893-901.

Chemical of Concern: CLNSM,THF,CRM,BMN; Habitat: T; Code: TARGET(CLNS).

Soltani, Nader, Shropshire, Christy, Cowan, Todd , and Sikkema, Peter (2004). White bean sensitivity to 

preemergence herbicides. Weed Technol. 18: 675-679.

Chemical of Concern: CLNSM; Habitat: T; Code: TARGET(CLNS).

Soltani, Nader and Sikkema, Peter H (2005). White bean (Phaseolus vulgaris) tolerance to preplant-incorporated 

herbicides. Weed Biol. Manage. 5: 35-38.

Chemical of Concern: CLNSM; Habitat: T; Code: TARGET(CLNS).

Stachler, J. (2008). Characterization and management of glyphosate-resistant giant ragweed (Ambrosia trifida L.) 

and horseweed [Conyza canadensis (L.) cronq.]. 

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Taylor, Jeffrey B., Loux, Mark M., Harrison, S. Kent, and Regnier, Emilie (2002). Response of ALS-resistant 

common ragweed (Ambrosia artemisiifolia) and giant ragweed (Ambrosia trifida) to ALS-inhibiting and 

alternative herbicides. Weed Technol. 16: 815-825.

Chemical of Concern: CLNSM,GYP,LCF,FSF; Habitat: T; Code: TARGET(CLNS).

Trainer, Geoffrey D., Loux, Mark M., Harrison, S. Kent, and Regnier, Emilie (2005). Response of horseweed 

biotypes to foliar applications of cloransulam-methyl and glyphosate. Weed Technol. 19: 231-236.
-66 of 85-

Chemical of Concern: CLNSM,GYP; Habitat: T; Code: TARGET(CLNS).

Trezzi, Michelangelo M., Felippi, C. L., Mattei, D., Silva, H. L., Nunes, A. L., Debastiani, C., Vidal, R. A., and 

Marques, A (2005). Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors 

in Euphorbia heterophylla biotypes. J. Environ. Sci. Health, Part B B40: 101-109.

Chemical of Concern: CLNS,FSF,IZT; Habitat: T; Code: TARGET(CLNS).

Ulloa Cortazar, S. (2007 ). Response of Asiatic dayflower (Commelina communis L.) to glyphosate and alternatives 

in soybean. 

Chemical of Concern: CLNSM,GYP,LCT,MBZ; Habitat: T; Code: TARGET(CLNS).

Ulloa, Santiago M. and Owen, Micheal D. K (2009). Response of Asiatic dayflower (Commelina communis) to 

glyphosate and alternatives in soybean. Weed Sci. 57: 74-80.

Chemical of Concern: CLNS,GYP; Habitat: T; Code: TARGET(CLNS).

Vangessel, Mark J (1999). Control of perennial weed species as seedlings with soil-applied herbicides. Weed 

Technol. 13: 425-428.

Chemical of Concern: CLNS,MBZ,CMZ; Habitat: T; Code: TARGET(CLNS).

Vangessel, Mark J., Monks, David W., and Johnson, Quintin R (2000). Herbicides for potential use in lima bean 

(Phaseolus lunatus) production. Weed Technol. 14: 279-286.

Chemical of Concern: CLNS,LCF; Habitat: T; Code: TARGET(CLNS).

Vyn, J. D., Swanton, C. J., Weaver, S. E., and Sikkema, P. H (2007). Control of herbicide-resistant common 

waterhemp (Amaranthus tuberculatus var. rudis) with pre- and post-emergence herbicides in soybean. Can. 

J. Plant Sci. 87: 175-182.

Chemical of Concern: CLNS,MTL,LNR,FSF,GYP,ACF; Habitat: T; Code: TARGET(CLNS).

Westhoven, Andrew M., Stachler, Jeff M., Loux, Mark M., and Johnson, William G (2008). Management of 

glyphosate-tolerant common lambsquarters (Chenopodium album) in glyphosate-resistant soybean. Weed 

Technol. 22: 628-634.

Chemical of Concern: CLNSM,GYP; Habitat: T; Code: TARGET(CLNS).

Whaley, Cory M., Wilson, Henry P., and Westwood, James H (2006). ALS resistance in several smooth pigweed 

(Amaranthus hybridus) biotypes. Weed Sci. 54: 828-832.

Chemical of Concern: CLNS,IZT,CRM,THF,PTB; Habitat: T; Code: TARGET(CLNS).

Whaley, Cory M., Wilson, Henry P., and Westwood, James H (2007). A new mutation in plant ALS confers 

resistance to five classes of ALS-inhibiting herbicides. Weed Sci. 55: 83-90.

Chemical of Concern: CLNS,CRM,IZT,THF; Habitat: T; Code: TARGET(CLNS).

Wheeler, Melissa Ann Monique (2005). Impact of mutations in acetolactate synthase on resistance of redroot 

pigweed (Amaranthus retroflexus L.) and green pigweed (Amaranthus powellii S. Wats) to flucarbazone 

and pyrithiobac. 
-67 of 85-

Chemical of Concern: CLNS,PTB,FCB,IZX,CRM,FMS,FTS; Habitat: T; Code: TARGET(CLNS).

Yenish, Joseph P. and Eaton, Nichole A (2002). Weed control in dry pea (Pisum sativum) under conventional and 

no-tillage systems. Weed Technol. 16: 88-95.

Chemical of Concern: CLNS,IZT,FTS,SFZ,BT,FSF,IZX; Habitat: T; Code: TARGET(CLNS).

York, Alan C., Stewart, Alexander M., Vidrine, P. Roy, and Culpepper, A. Stanley (2004). Control of volunteer 

glyphosate-resistant cotton in glyphosate-resistant soybean. Weed Technol. 18: 532-539.

Chemical of Concern: CLNS,FTS,IMQ,MBZ,CRM,SFZ,GYP; Habitat: T; Code: TARGET(CLNS).

Zelaya, Ian A. and Owen, Micheal D. K (2004). Evolved resistance to acetolactate synthase-inhibiting herbicides in 

common sunflower (Helianthus annuus), giant ragweed (Ambrosia trifida), and shattercane (Sorghum 

bicolor) in Iowa. Weed Sci. 52: 538-548.

Chemical of Concern: CLNS,IZT,CRM,NSF; Habitat: T; Code: TARGET(CLNS).

Zheng, D. (2007). Resistance to ALS-inhibiting herbicides in common ragweed, foxtail and horseweed. 

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).

Zheng, D., Patzoldt, W. L., and Tranel, P. J. (2005). Association of the W574L ALS Substitution with Resistance to 

Cloransulam and Imazamox in Common Ragweed (Ambrosia artemisiifolia). Weed Sci. 53: 424-430.

Chemical of Concern: CLNS; Habitat: T; Code: TARGET(CLNS).
-68 of 85-

APPENDIX D. Submitted Ecological Effects Toxicity Data for Cloransulam-methyl

TABLE 1. Ecological Effects Data for Terrestrial and Aquatic Animals

SPECIES ENDPOINT

CHEMICAL/

FORMULATI

ON

MRID

STUDY 

CLASSIFICATIONCOMMENTS

BIRDS

Birds (Acute)

Bobwhite quail

(Colinus 

virginianus)

14-day LD50 > 

2250 mg 

a.i./kg-bw

Cloransulammethyl (97.3%) 43003407 Acceptable

Birds (Acute/Sub-Acute)

Mallard Duck

(Anas 

platyrhynchos)

8-day LC50 > 

5620 mg 

a.i./kg-diet

Cloransulammethyl (97.3%) 43003408 Acceptable

Bobwhite quail 

(Colinus 

virginianus)

8-day LC50 >

5620 mg 

a.i./kg-diet

Cloransulammethyl (97.3%) 43003409 Acceptable

Birds (Chronic)

Mallard Duck 

(Anas 

platyrhynchos)

NOAEC:127 

mg a.i./kg diet

LOAEC: 485 

mg a.i./kg diet

Cloransulammethyl (97.3%) 436993-01 Acceptable

Endpoints 

based on 

decrease in 

eggshell 

thickness and 

live embryos 

per viable 

embryos.

Bobwhite quail 

(Colinus 

virginianus)

NOAEC: <654 

mg a.i./kg diet

LOAEC: 654 

mg a.i./kg diet

Cloransulammethyl (97.3%) 436689-05 Supplemental

Endpoints 

based on 

decreases in 

eggs set/pen, 

viable 

embryos/pen, 

No. 

Hatchlings/pen, 

Hatchling 

survival/pen 

MAMMALS

Mammals (Acute)

Laboratory Rat

(Rattus 

norvegicus)

LD50 > 5000 

mg a.i./kg-bw

Cloransulammethyl 43003413 Minimum

Satisfies 

guideline

requirements

Laboratory Rat 

– Fischer 344 

LD50 > 5000 

mg a.i./kg-bw 

(M& F)

Firstrate 

(84.8%) 43003419 Minimum

Satisfies 

guideline 

requirements

SpragueDawley Rat 

Male LD50 = 

2504 mg 

a.i./kg-bw

Female LD50 = 

3803 a.i./kg-bw

Gauntlet 70 DF 

(8.1%) 45388202 Acceptable

Need to 

confirm study 

with RD

Mammals (Chronic)
-69 of 85-

SPECIES ENDPOINT

CHEMICAL/

FORMULATI

ON

MRID

STUDY 

CLASSIFICATIONCOMMENTS

SpragueDawley Rat

NOAEL = 10 

mg/kg-bw

LOEAL = 100 

mg/kg-bw

Based on 

parental 

systemic 

toxicity

Cloransulammethyl 43668911 Acceptable

TERRESTRIAL INVERTEBRATES

Honey Bee

(Apis melifera)

LD50 > 25 μg 

a.i./bee

Cloransulammethyl (97.3%) 43003431 Acceptable

FRESHWATER FISH 

Freshwater Fish (Acute)

Bluegill Sunfish

(Lepomis 

macrochirus)

96-hr LC50 > 

154 mg a.i./L

Cloransulammethyl (97.3%) 43003411 Acceptable

Rainbow Trout

(Oncorhynchus 

mykiss)

96-hr LC50 > 86 

mg a.i./L

Cloransulammethyl (97.3%) 43003410 Acceptable

Freshwater Fish (Chronic)

ESTUARINE/MARINE FISH

Estuarine/Marine Fish (Acute)

Inland 

Silverside

(Menidia 

beryllina)

96-hr LC50 > 

121 mg a.i./L

Cloransulammethyl (97.4%) 43718901 Acceptable

Estuarine/Marine Fish (Chronic)

FRESHWATER INVERTEBRATES

Freshwater Invertebrates (Acute)

Waterflea 

(Daphnia 

magna)

--

Cloransulammethyl (97.3%) 43003412 Invalid

Freshwater Invertebrates (Chronic)

ESTUARINE/MARINE INVERTEBRATES

Estuarine/Marine Invertebrate (Acute)

Eastern Oyster

(Crassostrea 

virginica)

96-hr LC50 > 

111 mg a.i./L

Cloransulammethyl (97.4%) 43718902 Acceptable

Grass Shrimp

(Palaemonetes 

pugio)

96-hr LC50 > 

121 mg a.i./L

Cloransulammethyl (97.4%) 43718903 Acceptable

Estuarine/Marine Invertebrate (Chronic)
-70 of 85-

TABLE 2. Cloransulam-methyl Ecological Effects Data for Terrestrial Plants

Seedling Emergence Tier II Toxicity Test

Species EC25

(lbs 

a.i./L)

NOAEC 

(lbs 

a.i./L)

Most 

Sensitive 

Endpoint

Compound MRID Classification Comment

Radish 0.00356 0.00145 Fresh 

weight

Cloransula

m-methyl

(98.2%)

43715404 Supplemental Conducted 

on the 

TGAI and 

not the TEP Onion 0.00356 0.00289 Shoot 

length

Tomato 0.00487 0.00145 Fresh 

weight

Carrot 0.00956 0.00289 Fresh 

weight

Ryegrass 0.0297 0.0231 Shoot 

length

Corn >0.0462 0.0231 Shoot 

length

Soybean >0.0462 0.0231 Shoot 

length

Cotton >0.0462 0.02310 Fresh 

Weight

Pinto Bean >0.0462 0.0462 None

Wheat >0.0462 0.0462 None

TABLE 3. Degradate Ecological Effects Data for Terrestrial Plants

Seedling Emergence Tier I/II Toxicity Test

Species EC25

(lbs 

a.i./A)

NOAEC 

(lbs 

a.i./A)

Most 

Sensitive 

Endpoint

Compound MRID Classificati

on

Comment

Radish

>0.048

4 lbs 

ai/A

0.0484 lbs 

ai/A

Length, 

Fresh 

Weight, 

Emergenc

e

5-hydroxycloransulmmethyl44744516 The 

study on 

cloransu

lam is 

Accepta

ble; 5-

OHcloransu

lam is

Supple

mental. 

The

study on 

5-OHcloransu

lammethyl 

is

Supple

mental. 

Conducted 

on the 

TGAI and 

not the TEP 5-hydroxycloransulm

cloransulam

Vegetative Vigor Tier I/II Toxicity Test
-71 of 85-

Species EC25

(lbs 

a.i./A)

NOAEC 

(lbs 

a.i./A)

Most 

Sensitive 

Endpoint

Compound MRID Classification Comment

Radish 0.0118 

lbs ai/A

0.00654 

lbs ai/A Fresh 

Weight

5-hydroxycloransulmmethyl44744516 The study 

on 

cloransula

m is 

Acceptabl

e; 5-OHcloransula

m is

Suppleme

ntal. The

study on 

5-OHcloransula

m-methyl 

is

Suppleme

ntal. 

Conducted 

on the 

TGAI and 

not the 

TEP; Study 

duration not 

reported 

5-hydroxycloransulm

cloransula

m

TABLE 4. Ecological Effects Data for Aquatic Plants

SPECIES ENDPOINT

CHEMICAL/

FORMULATION 

(percent active 

ingredient)

MRID

STUDY 

CLASSIFICATIONCOMMENTS

Aquatic Nonvascular Plants

Green Alga 

(Psuedokirchneriella 

subcapitata,reported 

as Selenastrum 

apricornutum)

96-hr EC50 = 

0.003 mg a.i./L 

NOAEC = 

0.00094 mg 

a.i./L

TEP (FirstRate) 

(82.2%) 44744517 Acceptable

Green Alga 

(Psuedokirchneriella 

subcapitata, 

reported as 

Selenastrum 

capricornutum

Printz)

Unknown; 

study could not 

derive endpoint

5-hydroxycloransulammethyl (not 

reported)

43760003 Supplemental

Cyanobacteria 

(Anabaena flosaquae)

120-hr EC50

>29.9 mg a.i./L

NOAEC = 29.9 

mg a.i./L

5-hydroxycloransulammethyl (>95%)

44744501 Supplemental

Freshwater Diatom 

(Navicula 

pelliculosa)

--

5-hydroxycloransulammethyl (>95%)

44744502 Invalid

Saltwater Diatom 

(Skeletonema 

costatum)

120-hr EC50 > 

93.3 mg a.i./L

NOAEC = 93.3 

mg a.i./L

5-hydroxycloransulammethyl (>95%)

44744503 Acceptable
-72 of 85-

Green Alga 

(Psuedokirchneriella 

subcapitata,reported 

as Selenastrum 

apricornutum

Printz)

96-hr EC50 > 

26.3 mg a.i./L

NOAEC = 26.3 

mg a.i./L 

5-hydroxycloransulammethyl (>95%)

44744504 Supplemental

Green Alga

(Psuedokirchneriella 

subcapitata, 

reported as 

Selenastrum 

capricornutum

Printz)

Unknown; 

study could not 

derive endpoint

5-hydroxycloransulam (not 

reported)

43760004 Supplemental

Cyanobacteria 

(Anabaena flosaquae)

120-hr EC50 = 

>26.5 mg a.i./L

NOAEC = 26.5 

mg a.i./L

5-hydroxycloransulam 

(>96%)

44744506 Supplemental

Freshwater Diatom 

(Navicula 

pelliculosa)

120-hr EC50 = 

>10.7 mg a.i./L

NOAEC = 5.64 

mg a.i./L

5-hydroxycloransulam 

(>96%)

44744507 Supplemental

Saltwater Diatom 

(Skeletonema 

costatum)

120-hr EC50

>103 mg a.i./L

NOAEC = 103 

mg a.i./L

5-hydroxycloransulam 

(>97%)

44744508 Acceptable

Green Alga 

(Psuedokirchneriella 

subcapitata,reported 

as Selenastrum 

apricornutum

Printz)

96-hr EC50 = 

>27.9 mg a.i./L

NOAEC = 27.9 

mg a.i./L

5-hydroxycloransulam 

(>97%)

44744509 Supplemental

Freshwater Diatom 

(Navicula 

pelliculosa)

120-hr EC50 = 

>47.5 mg a.i./L

NOAEC = 47.5 

mg a.i./L

Cloransulam 

(>96%) 44744512 Supplemental

Cyanobacteria 

(Anabaena flosaquae)

120-hr EC50

>3.65, <7.71 

mg a.i./L 

NOAEC = 3.65 

mg a.i./L

Cloransulam 

(>96%) 44744511 Supplemental

Saltwater Diatom 

(Skeletonema 

costatum)

120-hr EC50 > 

90.8 mg a.i./L 

NOAEC = 90.8 

mg a.i./L

Cloransulam 

(>96%) 44744513 Acceptable

Green Alga

(Psuedokirchneriella 

subcapitata,reported 

as Selenastrum 

apricornutum

Printz)

96-hr EC50 = 

0.0074 mg 

a.i./L

EC05 =0.0021

mg a.i./L

Cloransulam 

(>96%)

44744514; 

43668917 Acceptable

Aquatic Vascular Plants
-73 of 85-

Duckweed

(L. gibba)

--

Cloransulammethyl (97.3%) 43668916 Invalid

The results of 

this study do 

not fully meet 

guideline 

standards based 

on test 

substance 

instability, 

control 

contamination, 

and uncertainty 

regarding the 

effects of the 

solvent 

Duckweed

(L. gibba)

14-day EC50 = 

110 mg a.i./L 

(frond number)

NOAEC = 58.3 

mg a.i./L 

(frond number 

& growth rate)

5-hydroxycloransulammethyl (>95%)

44744505 Supplemental

Duckweed

(L. gibba)

14-day EC50 = 

≥ 100 mg a.i./L 

(frond number)

NOAEC = 53.6 

mg a.i./L

5-hydroxycloransulam 

(>97%)

44744510 Acceptable

Duckweed

(L. gibba)

14-day EC50 = 

0.130 mg a.i./L 

(frond number)

NOAEC = 

0.0611mg 

a.i./L

Cloransulam 

(>96%) 44744515 Acceptable
-74 of 85-

APPENDIX E: SIP v.1.0 Description, Assumptions, Inputs and Outputs

SIP v.1.0 provides an upper bound estimate of exposure of birds and mammals to pesticides through 

drinking water alone. This model is intended for use in problem formulation to determine whether or not 

drinking water exposure alone is a potential pathway of concern. This does not aggregate drinking water 

exposure with other exposure routes (i.e., diet, inhalation, dermal).

Assumptions:

SIP employs the following conservative assumptions to derive upper bound exposure 

estimates:

1) The chemical concentration in drinking water is at the solubility limit in water (at 25oC).

2) The assessed animals obtain 100% of their daily water needs through drinking water.

3) The daily water need is equivalent to the daily water flux rate as calculated by Nagy and 

Peterson (1988).

4) The body weight of the assessed bird is equivalent to the smallest generic bird modeled in 

T-REX (i.e., 20 g). This assumption results in the highest ratio of exposure to toxicity for the 3 

assessed avian body weights of T-REX (i.e., 20, 100, 1000 g).

5) The body weight of the assessed mammal is equivalent to the largest generic mammal 

modeled in T-REX (i.e., 1000 g). This results in the highest ratio of exposure to toxicity for the 3 

assessed mammalian body weights of T-REX (i.e., 15, 35, 1000 g). 
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Table 1. Inputs

Parameter Value

Chemical name Cloransulam-methyl

Solubility (in water at 25oC; 

mg/L) 3400

Mammalian LD50 (mg/kg-bw) 5000

Mammalian test species laboratory rat

Body weight (g) of "other" 

mammalian species

Mammalian NOAEL (mg/kg-bw) 100

Mammalian test species laboratory rat

Body weight (g) of "other" 

mammalian species

Avian LD50 (mg/kg-bw) 2250

Avian test species northern bobwhite quail

Body weight (g) of "other" avian 

species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet) 0

Bobwhite quail NOAEC (mg/kgdiet) 0

NOAEC (mg/kg-diet) for other 

bird species

Body weight (g) of other avian 

species

NOAEC (mg/kg-diet) for 2nd 

other bird species

Body weight (g) of 2nd other 

avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kgbw) 584.8000 584.8000

Adjusted toxicity value (mg/kgbw) 3845.8028 76.9161

Ratio of exposure to toxicity 0.1521 7.6031

Conclusion*

Exposure through 

drinking water alone is 

a potential concern for 

mammals

Exposure through drinking 

water alone is a potential 

concern for mammals
-76 of 85-

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kgbw) 2754.0000 2754.0000

Adjusted toxicity value (mg/kgbw) 1620.9664 0.0000

Ratio of exposure to acute 

toxicity 1.6990 0.0000

Conclusion*

Exposure through 

drinking water alone is 

a potential concern for 

birds

Due to insufficient data, risk 

cannot be precluded

*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.
-77 of 85-

APPENDIX F: Data Call-In Tables

The Environmental Fate and Effects Division (EFED) has completed a Data Call-In (DCI) table 

for the cloransulam-methyl environmental fate and effects data gaps identified in Registration 

Review. The attached DCI table, which includes the guideline number and study title for 

required data, also provides a rationale for requiring the data, an explanation of how the data will 

be used, and a brief description of how the data could impact the Agency‟s future decisionmaking.

Guideline Number: 835.4300

Study Title: Aerobic Aquatic Metabolism

Rationale for Requiring the Data

Acceptable data on the aerobic aquatic metabolism of cloransulam-methyl in two sediment systems are 

required under 40 CFR Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial 

uses. Submitted aerobic aquatic metabolism data were classified as not acceptable. The Agency has a 

limited understanding of how cloransulam-methyl behaves in aerobic aquatic environments once applied. 

Data are needed for two sediment-water systems conducted (one each) at neutral and acidic pHs. 

Practical Utility of the Data

How will the data be used?

Aerobic aquatic metabolism data will facilitate a better understanding of the fate of cloransulam-methyl 

residues in water. If data indicate that degradation in aerobic conditions occurs rapidly in neutral and 

acidic aquatic systems and produces nontoxic transformation products, then the Agency could potentially 

determine that cloransulam-methyl residues of concern do not persist in these systems. If data indicate 

that degradation is not appreciable in aquatic systems or that the transformation products are of similar or 

higher toxicity than the parent compound, then the Agency could conclude that cloransulam-methyl 

residues of concern persist in acidic aquatic systems under anaerobic conditions. 

How could the data change the Agency’s decision or impact the Agency’s future decision-making? 

In the absence of the requested data, cloransulam-methyl aerobic aquatic metabolism half-lives will be 

conservatively assumed to be stable at a neutral pH, or less conservatively at two times the aerobic soil 

metabolism half-life modeling input value. If the required data indicate that cloransulam-methyl in 

aerobic aquatic environments is rapidly biodegraded to nontoxic degradation products, then risk 

assessment conclusions and associated labeled use precautions and/or restrictions could be made less 

restrictive.

Guideline Number: 835.4400

Study Title: Anaerobic Aquatic Metabolism

Rationale for Requiring the Data

Acceptable data on the anaerobic aquatic metabolism of cloransulam-methyl are required under 40 CFR 

Part 158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Anaerobic aquatic 

metabolism data have only been submitted for one sediment, but were classified supplemental, whereas 

acceptable data for two sediments are required. The Agency has a limited understanding of how 

cloransulam behaves in anaerobic aquatic environments once applied. An anaerobic aquatic metabolism 

study of cloransulam-methyl (MRID 43715403) was submitted to the Agency. However, data are needed 

for two additional sediment-water systems conducted at a neutral and an acidic pH. The current 
-78 of 85-

supplemental study will be used for risk assessment purposes, however additional studies conducted in an 

acidic (low pH) system and a neutral pH system is required to fulfill the guideline and better understand 

the potential variability in the biotic degradation in oxygen limiting aquatic environments. Thus, the 

Agency is requiring an OCSPP guideline-compliant anaerobic aquatic metabolism study with two 

systems, one each at a neutral pH and one at an acidic pH. 

Practical Utility of the Data

How will the data be used?

Anaerobic aquatic metabolism data will facilitate a better understanding of the fate of cloransulammethyl residues in water. If data indicate that degradation in anaerobic conditions occurs rapidly in 

acidic and/or neutral aquatic systems and produces nontoxic transformation products, then the Agency 

could potentially determine that cloransulam-methyl residues of concern do not persist in these systems. 

If data indicate that degradation is not appreciable in aquatic systems or that the transformation products 

are of similar or higher toxicity than the parent compound, then the Agency could conclude that 

cloransulam-methyl residues of concern persist in acidic aquatic systems under anaerobic conditions. 

How could the data change the Agency’s decision or impact the Agency’s future decision-making? 

In the absence of the requested data, cloransulam-methyl anaerobic aquatic metabolism half-lives will be 

conservatively assumed to be stable at a neutral pH, or less conservatively three times the current 

anaerobic soil metabolism half-life. However, since the compound is hydrolytically stable at neutral and 

acidic pHs, the current study (which does not clearly identify the system pH) does not accurately capture 

the potential variability in the anaerobic degradation rates. If the required data indicate that cloransulammethyl in anaerobic aquatic environments is rapidly biodegraded to nontoxic degradation products, then 

risk assessment conclusions and associated labeled use precautions and/or restrictions could be made less 

restrictive.

Guideline Number: 835.4200

Study Title: Anaerobic Soil Metabolism

Rationale for Requiring the Data

Acceptable data on the anaerobic soil metabolism of cloransulam-methyl are required under 40 CFR Part 

158, Subpart N (revised July 1, 2009) for labeling that includes terrestrial uses. Currently, there are no 

submitted studies that satisfy the guideline. Therefore, the Agency has a limited understanding of how 

cloransulam-methyl behaves in anaerobic soil environments once applied. Depending on how quickly, to 

what extent, and to which transformation products the compound degrades, cloransulam-methyl may or 

may not pose a potential for ground water contamination. Because cloransulam-methyl degradation in 

anaerobic soil systems is not well understood, the Agency is requiring an OCSPP guideline-compliant 

anaerobic soil metabolism study.
-79 of 85-

Practical Utility of the Data

How will the data be used?

Anaerobic soil metabolism data will facilitate a better understanding of the fate of cloransulam-methyl 

residues in subsurface soil, and anaerobic sediments. If data indicate that degradation in anaerobic 

conditions occurs rapidly and produces nontoxic transformation products, then the Agency could 

potentially determine that cloransulam-residues residues of concern do not persist in these systems. If 

data indicate that degradation is not appreciable in anaerobic systems or that the transformation products 

are of similar or higher toxicity than the parent compound, then the Agency could conclude that 

cloransulam-methyl residues of concern persist in anaerobic soil systems. 

How could the data change the Agency’s decision or impact the Agency’s future decision-making? 

In the absence of the requested data, cloransulam-methyl anaerobic soil metabolism half-lives will be 

conservatively assumed stable. If the required data indicate that cloransulam-methyl in anaerobic soil

environments is rapidly biodegraded to nontoxic degradation products, then risk assessment conclusions 

and associated labeled use precautions and/or restrictions could be made less restrictive.

Guideline Number: 835.6100

Study Title: Storage Stability

Rationale for Requiring the Data

Acceptable data on the frozen storage stability of cloransulam-methyl are required under 40 CFR Part 

158, Subpart N (revised July 1, 2009), for labeling that includes terrestrial uses, as part of the submitted 

terrestrial field dissipation studies. The Agency has a limited understanding of how cloransulam-methyl 

behaves in frozen storage conditions between the time of sampling and the time of analysis. One study 

(MRID 430034-34) showed extracted residues decreased as a result of frozen storage prior to analysis. 

Submission of a storage stability study is essential in order to be confident that any degradation measured 

in the test system was due solely to the environment of that test system, and not due to handling and 

storage.

Practical Utility of the Data

How will the data be used?

Storage stability data will facilitate a better understanding of the fate of cloransulam-methyl residues

during storage and handling between sampling and analysis. If data indicate that significant degradation 

of cloransulam-methyl or its degradates occur then the data from the field studies are no longer valid as it 

would not be feasible to determine if the degradation measured in the test system was due solely to the 

environment of that test system, and not due to handling and storage.

How could the data change the Agency’s decision or impact the Agency’s future decision-making? 

In the absence of the required data, the field data for cloransulam-methyl will be qualitatively used in the 

risk assessment. These data are used for confirmatory purposes to ensure that any degradation observed 

in the test systems is due solely to the test environment and not handling or storage.
-80 of 85-

Guideline Number: 835.6100 

Study Title: Analytical Method (and Associated Independent Laboratory Validation) for Residues 

in Sediment

Rationale for Requiring the Data

Independently validated analytical methods for residues in soil, water, sediment, and plant material 

(environmental chemistry methods) submitted by the registrant are used to evaluate analyses described in 

submitted environmental fate and ecological effects studies. Submitted analytical methods are also used 

by various Federal, State, Tribal, and local agencies to detect and monitor residues that are or are 

suspected to be in environmental compartments due to outdoor uses and accidental releases. Independent 

laboratory validations for submitted analytical methods are necessary to confirm that the methods are 

functional and to confirm the levels of detection and quantitation reported in registrant-prepared 

validations.

Practical Utility of the Data

How will the data be used?

In the absence of independently validated environmental chemistry methods, submitted environmental 

fate and ecological effects data may not be reviewable and entities outside the Agency may lack 

chemical-specific methods for analyses in environmental compartments. Independently validated 

environmental chemistry methods will be used to evaluate submitted environmental fate and ecological 

effects data and will be made available for enforcement and monitoring purposes at the federal, state, and 

local levels.

How could the data change the Agency’s decision, or impact the Agency’s future decision-making? 

Risk assessment conclusions could be altered if they are not supported by either study data or 

environmental monitoring detections that are based on independently validated environmental chemistry 

methods. Furthermore, while not directly related to Agency decision-making, independently validated 

environmental chemistry methods are necessary to ensure the safety of those in proximity to releases of 

cloransulam-methyl residues in the environment.

Guideline Number: 850.2300 

Study Title: Avian Reproduction Test 

Rationale for Requiring the Data

Under the 40 CFR Part 158 (Oct. 26, 2007) data requirements for conventional pesticides, avian 

reproduction data are required on waterfowl and upland game species (OCSPP Guideline 850.2300). 

Data for cloransulam-methyl are have been reviewed for both an upland game species (bobwhite quail), 

MRID 436689-05, and waterfowl species (mallard duck), MRID 436993-01. The bobwhite quail study 

resulted in significant adverse effects at the lowest treatment concentration. The NOAEC for the 

bobwhite quail was determined to be <654 mg a.i./kg-diet based on number of eggs set, number of viable 

embryos, number of live embryos, number hatched, and hatchling survival. The NOAEC based on these 

parameters in the mallard study is 1,505 mg a.i./kg-diet, indicating that for certain parameters, the 

bobwhite quail is more sensitive to cloransulam-methyl. Therefore, since a definitive NOAEC value is 

required, an additional study of bobwhite quail is recommended.

Practical Utility of the Data

How will the data be used?

Reproduction data for bobwhite quail will be used to reduce uncertainties associated with using data from 

a potentially-less sensitive species (mallard duck) to assess chronic risks to birds and by extension to 

terrestrial-phase amphibians and reptiles from cloransulam-methyl exposure. If reproduction toxicity 

data are not submitted for bobwhite quail, the current non-definitive NOAEC would be used to assess 

chronic avian risk and all chronic risk quotients would be assumed greater than their actual value. As 

such, chronic risk to birds from cloransulam-methyl use on soybeans would be presumed.
-81 of 85-

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without these data, the Agency would have 

to assume that cloransulam-methyl “may affect” listed birds, reptiles, and terrestrial-phase amphibians 

directly (and listed species from other taxa indirectly), and use of cloransulam-methyl and its formulated 

products may need to be restricted in areas where listed species could be exposed. The lack of these data 

will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered 

Species Act and could result in use restrictions for cloransulam-methyl use that are unnecessarily severe.

Guideline Number: 850.1010

Study Title: Acute Freshwater Invertebrate Toxicity Test

Rationale for Requiring the Data

The CFR Part 158 data requirements specify that acute toxicity data on freshwater invertebrates are 

required for the registration of pesticides with outdoor uses. Scientifically valid acute toxicity data are 

not available for freshwater invertebrates. Additionally, no data exists on the chronic exposure of 

cloransulam-methyl to freshwater invertebrates that could suggest cloransulam-methyl is practically nontoxic to freshwater invertebrates. An acute freshwater invertebrates toxicity test (OCSPP 850.1010) is 

requested at this time. 

Practical Utility of the Data

How will the data be used?

Acute freshwater invertebrate toxicity data will be used to determine the potential for cloransulam-methyl 

to affect invertebrate species in freshwater environments. The data will reduce uncertainties associated 

with the current risk assessment for freshwater invertebrates and will improve the Agency‟s 

understanding of the potential effects of cloransulam-methyl on aquatic animals. In the absence of data 

specific for these invertebrates, risk to freshwater invertebrates will be presumed.

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without these data, the Agency would have 

to assume that cloransulam-methyl “may affect” listed freshwater invertebrates directly (and listed 

species from other taxa indirectly), and use of cloransulam-methyl and its formulated products may need 

to be restricted in areas where listed species could be exposed. The lack of these data will limit the 

flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act 

and could result in use restrictions for cloransulam-methyl use that are unnecessarily severe.

Guideline Number: 850.1300

Study Title: Freshwater Invertebrate Life Cycle Toxicity Test

Rationale for Requiring the Data

The Agency has worked to finalize the data requirements updates in 40 CFR Part 158. These updated 

data requirements were promulgated in October 2007. As a result, one freshwater invertebrate life-cycle 

study (OCSPP 850.1300) is required to support all terrestrial use patterns. Chronic toxicity data are 

currently unavailable for freshwater invertebrates and a life cycle toxicity test is requested at this time. 

Practical Utility of the Data

How will the data be used?

Chronic freshwater invertebrate toxicity data will be used to determine the potential for cloransulammethyl to affect reproduction, growth and survival of invertebrate species in freshwater environments

following prolonged exposure. The data will reduce uncertainties associated with the current risk 

assessment for freshwater invertebrates and will improve the Agency‟s understanding of the potential 

chronic effects of cloransulam-methyl on aquatic animals. In the absence of data specific for these 

invertebrates, chronic risk to freshwater invertebrates will be presumed.

How could the data impact the Agency’s future decision-making?
-82 of 85-

If future endangered species risk assessments are performed without these data, the Agency would have 

to assume that cloransulam-methyl “may affect” listed freshwater invertebrates directly (and listed 

species from other taxa indirectly), and use of cloransulam-methyl and its formulated products may need 

to be restricted in areas where listed species could be exposed. The lack of these data will limit the 

flexibility the Agency and registrants have in coming into compliance with the Endangered Species Act 

and could result in use restrictions for cloransulam-methyl use that are unnecessarily severe.

Guideline Number: 850.1400

Study Title: Fish Early-Life Stage Toxicity Test, Freshwater

Rationale for Requiring the Data

The Agency has worked to finalize the data requirements updates in 40 CFR Part 158. These updated 

data requirements were promulgated in October 2007. As a result, one freshwater fish early-life stage

study (OCSPP 850.1400) is required to support all terrestrial use patterns. Chronic toxicity data are 

currently unavailable for freshwater fish and an early-life stage toxicity test is requested at this time. 

Practical Utility of the Data

How will the data be used?

Chronic freshwater fish toxicity data will be used to determine the potential for cloransulam-methyl to 

affect the reproduction, survival, and growth of fish in freshwater environments. The data will reduce 

uncertainties associated with the current risk assessment for freshwater fish (and by extension for aquaticphase amphibians as well) and will improve the Agency‟s understanding of the potential effects of 

cloransulam-methyl on aquatic animals. In the absence of data specific for these fish, chronic risk to 

freshwater fish and aquatic-phase amphibians will be presumed.

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without these data, the Agency would have 

to assume that cloransulam-methyl “may affect” listed freshwater fish and aquatic-phase amphibians

directly (and listed species from other taxa indirectly), and use of cloransulam-methyl and its formulated 

products may need to be restricted in areas where listed species could be exposed. The lack of these data 

will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered 

Species Act and could result in use restrictions for cloransulam-methyl use that are unnecessarily severe.

Guideline Number: 850.4225

Study Title: Terrestrial Plant Seedling Emergence Test (Tier II)

Rationale for Requiring the Data

Terrestrial plant toxicity studies are required for registration of pesticides with outdoor uses (CFR Part 

158). For known phytotoxicants, a Tier II seedling emergence study (OCSPP 850.4225) is required on a

TEP to investigate the effects of the pesticide end-use product on the emergence, growth, and survival of 

terrestrial plants. Although the available emergence study, MRID 437154-04, has been reviewed, the 

registration requirement for a Tier II seedling emergence test on a TEP has not been met. Because the 

toxicity of cloransulam-methyl to terrestrial plants is expected to be enhanced when formulated as a 

product with additional ingredients, such as surfactants, we recommend requesting a second Tier II 

seedling emergence toxicity study conducted on a TEP containing the single active ingredient 

cloransulam-methyl (i.e., Riverdale® and Firstrate® formulations). In the absence of this data, risk 

to plants off the application site would potentially be underestimated. 
-83 of 85-

Practical Utility of the Data

How will the data be used?

Tier II vegetative vigor data for terrestrial plants will be used to determine the potential for cloransulammethyl to affect non-target plant species in the terrestrial environment and to reduce uncertainties 

associated with the current risk assessment to terrestrial plants. In the absence of data specific to the 

emergence and initial growth life stages, the spatial extent of risk to terrestrial plants off the application 

site would potentially be underestimated.

How could the data impact the Agency’s future decision-making?

Because plants form the basis of most habitats and significantly contribute to overall environmental 

quality, a solid understanding of the potential risks to terrestrial plants is essential for sound 

environmental management. If the data indicates that registered cloransulam-methyl usage poses an even 

greater risk of adverse effects to non-target terrestrial plants above the Agency Level of Concern, the 

Agency may further explore decision options to mitigate this risk. The lack of data on the spatial extent 

of risk will limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act. 

Guideline Number: 850.4250

Study Title: Terrestrial Plant Vegetative Vigor Test (Tier II)

Rationale for Requiring the Data

Terrestrial plant toxicity studies and associated risk analysis of plants are required for registration of 

pesticides with outdoor uses (CFR Part 158). For known phytotoxicants, a Tier II vegetative vigor study

(OSCPP 850.4250) is required on a TEP to investigate the effects of the pesticide end-use product on the 

growth and survival of terrestrial plants. The available vegetative vigor study, MRID 437154-04, has 

been reviewed, but does not satisfy registration and guideline requirements. The registration requirement 

for a Tier II vegetative vigor test on a TEP has not been met, and the study does not appear to fully meet 

guideline standards based on notable guideline deviations. Because the toxicity of cloransulam-methyl to 

terrestrial plants is expected to be enhanced when formulated as a product with additional ingredients, 

such as surfactants, we recommend requesting a second Tier II vegetative vigor toxicity study conducted 

on a TEP containing the single active ingredient cloransulam-methyl (i.e., Riverdale® and 

Firstrate® formulations). In the absence of this data, risk to plants off the application site would 

potentially be underestimated. 

Practical Utility of the Data

How will the data be used?

Tier II vegetative vigor data for terrestrial plants will be used to determine the potential for cloransulammethyl to affect non-target plant species in the terrestrial environment and to reduce uncertainties 

associated with the current risk assessment to terrestrial plants. In the absence of data specific to the 

vegetative life stages, the spatial extent of risk to terrestrial plants off the application site would 

potentially be underestimated.

How could the data impact the Agency’s future decision-making?

Because plants form the basis of most habitats and significantly contribute to overall environmental 

quality, a solid understanding of the potential risks to terrestrial plants is essential for sound 

environmental management. If the data indicates that registered cloransulam-methyl usage poses an even 

greater risk of adverse effects to non-target terrestrial plants above the Agency Level of Concern, the 

Agency may further explore decision options to mitigate this risk. The lack of data on the spatial extent 

of risk will limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act. 
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Guideline Number: 850.4400 

Aquatic Plant Growth Tier II Study (Vascular plants)

Rationale for Requiring the Data

Aquatic vascular plant toxicity studies and associated risk analysis of aquatic vascular plants are required 

for registration of pesticides with outdoor uses (40 CFR Part 158). For known phytotoxicants, a Tier II 

aquatic vascular plant toxicity study (OCSPP Guideline 850.4400) on either the TGAI or TEP is required. 

The available vascular aquatic plant study with a TEP using L. gibba, MRID 436689-16, has been 

reviewed and does not appear to fully meet OCSPP Guideline standards due to a number of noted 

deficiencies and uncertainties (i.e., test substance instability, solvent control contamination, and solvent 

control effect uncertainty). These data are insufficient to quantitatively assess risk to aquatic vascular 

plants from cloransulam-methyl use.

Practical Utility of the Data

How will the data be used? 

These data will be used to estimate potential risks to aquatic vascular plants from cloransulam-methyl 

exposure. The data will reduce uncertainties associated with the current risk assessment for aquatic 

vascular plants and will improve our understanding of the potential effects of cloransulam-methyl use on 

aquatic vascular plants. Because plants form the basis of most habitats and significantly contribute to 

overall environmental quality, a solid understanding of the potential risks to aquatic plants is essential for 

sound environmental management. The data will also be used in determining whether a “may affect” to 

Federally-listed threatened and endangered species is likely under the Endangered Species Act.

How could the data impact the Agency’s future decision-making?

Without aquatic plant growth data for cloransulam-methyl, the Agency cannot determine the levels of 

cloransulam-methyl that result in effects to vascular aquatic plants. If these data are not available, risk to 

aquatic vascular plants will be presumed and the extent of risk from cloransulam-methyl usage could 

potentially be underestimated. The lack of these data will limit the flexibility the Agency and registrants 

have in coming into compliance with the Endangered Species Act, and could result in severe use 

restrictions for cloransulam-methyl, a known phytotoxicant, which may otherwise be avoided.

Guideline Number: 850.5400 

Algal Toxicity Tier II Study

Rationale for Requiring the Data

Aquatic (both vascular and non-vascular species) toxicity studies and associated risk analysis of plants 

are required for registration of pesticides with outdoor uses (CFR Part 158). For known phytotoxicants, 

four Tier II nonvascular toxicity studies (OCSPP Guideline 850.5400) on either the TGAI or 

TEP are required. There is currently only one available study on freshwater green algae to determine 

levels of cloransulam-methyl that could result in effects to aquatic non-vascular plants. Three more 

nonvascular plant studies are required as specified in 40 CFR Part 158; these include a study on a

freshwater diatom, saltwater diatom, and nitrifying cyanobacteria. 

Practical Utility of the Data

How will the data be used? 

This Tier II data will be used to adequately assess risks to aquatic nonvascular plants from cloransulammethyl exposure. The data will reduce uncertainties associated with the current risk assessment for 

aquatic nonvascular plants based currently on only one species and will improve our understanding of the 

potential effects of cloransulam-methyl use on aquatic plants. In the absence of data specific to 

freshwater diatoms, saltwater diatoms, and a nitrifying cyanobacteria, the extent of effects to nonvascular 

plants would be unknown and the extent of risk to aquatic plants could potentially be underestimated. 
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Because plants form the basis of most habitats and significantly contribute to overall environmental 

quality, a solid understanding of the potential risks to aquatic plants is essential for sound environmental 

management. As a known phytotoxicant, risk to aquatic plants from cloransulam-methyl use would be 

presumed in the absence of these data. The data will also be used in determining whether a “may affect” 

to Federally-listed threatened and endangered species is likely under the Endangered Species Act.

How could the data impact the Agency’s future decision-making?

Without additional nonvascular aquatic plant toxicity data for cloransulam-methyl, the Agency cannot 

determine with certitude the levels of cloransulam-methyl that result in effects to nonvascular aquatic 

plants. If this data is not available, the extent of risk to aquatic nonvascular plants from cloransulammethyl usage could potentially be underestimated. The lack of these data will limit the flexibility the 

Agency and registrants have in coming into compliance with the Endangered Species Act, and could 

result in severe use restrictions for cloransulam-methyl, a known phytotoxicant, which may otherwise be 

avoided.