2

studies needed to address uncertainties identified in the environmental fate and ecological effects 

database for chlorsulfuron.
3

Problem Formulation for the 

Environmental Fate and Ecological Risk, Endangered 

Species, and Human Health Drinking Water

Assessments in Support of the Registration Review of 

Chlorsulfuron

Chlorsulfuron (CAS 64902-72-3)

PC Code 118601

Prepared by:

Mary Clock-Rust, Biologist

Katrina White, Ph.D., Biologist

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:

Jim Carleton, Ph.D., Senior Fate Scientist

Thomas Steeger, Ph.D., Senior Biologist

Marietta Echeverria, Branch Chief

November 15, 2012
4

Table of Contents

1. Purpose........................................................................................................................................ 6

2. Description of Regulatory Action............................................................................................... 6

3. Conclusions from Previous Risk Assessments........................................................................... 6

4. Mechanism of Action.................................................................................................................. 8

5. Overview of Pesticide Usage ...................................................................................................... 8

6. Environmental Fate and Transport............................................................................................ 10

6.1. Monitoring Data................................................................................................................. 16

6.2. Clean Water Act................................................................................................................. 17

7. Receptors................................................................................................................................... 18

7.1. Effects to Aquatic Organisms............................................................................................ 20

7.2. Effects to Terrestrial Organisms........................................................................................ 21

7.3. Degradate Toxicity............................................................................................................. 23

7.4. Ecological Incidents........................................................................................................... 23

8. Evaluation of Non-definitive Toxicity Values.......................................................................... 25

9. Ecosystems Potentially at Risk ................................................................................................. 26

10. Assessment Endpoints ............................................................................................................ 26

11. Identification of Stressors of Concern .................................................................................... 26

12. Risk Hypothesis...................................................................................................................... 29

13. Exposure Pathways of Concern, Models, and Toxicity Endpoints......................................... 30

14. Analysis Plan .......................................................................................................................... 31

14.1. Measures of Exposure...................................................................................................... 32

14.1.A. Exposure in the Aquatic Environment ................................................................ 32

14.1.B. Exposure to Terrestrial Animals ......................................................................... 33

14.1.C. Exposure to Terrestrial Plants............................................................................. 33

14.1.D. Exposure to Spray Drift....................................................................................... 34

14.2. Measures of Effect ........................................................................................................... 34

14.3. Integration of Exposure and Effects ................................................................................ 35

14.3.A. Deterministic and Probabilistic Assessment Methods........................................ 35

14.4. Endangered Species Assessments.................................................................................... 36

14.5. Human Health Drinking Water Assessment.................................................................... 36

14.6. Endocrine Disruptor Screening Program......................................................................... 37

15. Preliminary Identification of Data Gaps................................................................................. 38

15.1. Fate................................................................................................................................... 38

15.1.A. Rationales for Requesting Fate Studies............................................................... 41

15.1.B Rationales for Not Requesting Fate Studies........................................................ 42

15.1.A. Additional Information that would be Useful for Monitoring and Risk 

Assessment............................................................................................................................ 43

15.2. Effects.............................................................................................................................. 43

15.2.A. Degradate Toxicity Data ..................................................................................... 46

16. Other Information Needs ........................................................................................................ 46

17. References............................................................................................................................... 47

17.1. Studies Related to Environmental Fate Data ................................................................... 50

17.2. Data submitted on Ecological Effects.............................................................................. 55
5

List of Tables

Table 1. Previously Estimated Drinking Water Concentrations for the Human Health Risk 

Assessment...................................................................................................................................... 8

Table 2. Summary of physical-chemical properties of chlorsulfuron1 ........................................ 10

Table 3. Abiotic and Biotic Transformation of Chlorsulfuron .................................................... 12

Table 4. Summary of Submitted Sorption Studies of Chlorsulfuron (MRID 42156705)2 .......... 14

Table 5. Summary of maximum amount of transformation products observed in fate studies. .. 16

Table 6. OPP Aquatic Life Benchmarks for Chlorsulfuron in μg a.i./L1 .................................... 17

Table 7. Most Sensitive Species Evaluated for Potential Ecological Effects from Chlorsulfuron.

....................................................................................................................................................... 18

Table 8. Summary of residues of concern for different classes of organisms............................. 28

Table 9. Summary of exposure pathways, endpoints, and models used in risk assessment........ 31

Table 10. Summary of Submitted Environmental Fate Studies, Study Classifications and Data 

Gaps for Chlorsulfuron and Its Degradates .................................................................................. 38

Table 11. Summary of Submitted Ecological Effects Studies and Data Gaps for Parent 

Chlorsulfuron ................................................................................................................................ 44

List of Figures

Figure 1. Potential Degradation Pathway of Chlorsulfuron Based on Degradates Obserbed in 

Laboratory and Field Studies........................................................................................................ 15

List of Appendices

Appendix A. List of Registered Products Containing Chlorsulfuron and Percent Active 

Ingredients..................................................................................................................................... 60

Appendix B. ECOSAR and ASTER Output................................................................................ 62

Appendix C. Ecological Toxicity Summary for Aquatic and Terrestrial Organisms from 

Chlorsulfuron ................................................................................................................................ 90

Appendix D. Results from Screening Imbibition Program (SIP) and the Screening Tool for 

Inhalation Risk Assessment (STIR).............................................................................................. 93

Appendix E. Example T-Rex Input and Output for Chlorsulfuron. ............................................ 96

Appendix F. Example Terrplant (v. 1.2.2) Input and Output for Chlorsulfuron ........................ 98

Appendix G. Reference List for OPPTS/OCSPP Fate Guidelines.............................................. 99

Appendix H. Identification of Transformation Products and Listing of the Maximum Amounts 

Observed in Fate Studies ............................................................................................................ 101

Appendix I. Justification of the Identified Residues of Concern............................................... 108
6

1. Purpose

The purpose of this problem formulation is to provide an understanding of the environmental fate 

and ecological effects of the registered uses of chlorsulfuron (1-(2-chlorophenylsulfonyl)-3-(4-

methoxy-6-methyl-1,3,5-triazin-2-yl)urea), the first registered sulfonyl urea herbicide in United 

States. It is a systemic pre or post-emergent herbicide used to control both grass and broadleaf 

weeds, and is registered for use on agricultural and nonagricultural crops.This document 

provides a plan for analyzing data relevant to chlorsulfuron and for conducting an environmental 

fate and ecological risk, Federally-listed endangered/threatened species (hereafter referred to as 

“listed” species), and human health drinking water assessments for its registered uses. 

Additionally, this problem formulation is intended to identify data gaps, uncertainties, and 

potential assumptions used to address those uncertainties, relative to characterizing the 

ecological risk associated with the registered uses of chlorsulfuron. 

2. Description of Regulatory Action

The Food Quality Protection Act of 1996 mandated the Environmental Protection Agency (EPA) 

to implement a new program for assessing the risks of pesticides, i.e., Registration Review 

(http://www.epa.gov/oppsrrd1/registration_review/). All pesticides distributed or sold in the 

United States generally must be registered by EPA. The decision to register a pesticide is based 

on the consideration of scientific data and other factors showing that it will not cause 

unreasonable risks to human health, workers, or the environment when used as directed on 

product labeling. The Registration Review program is intended to ensure that, as the ability to 

assess risk evolves and as policies and practices change, all registered 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,

and through the new Registration Review program, the Agency periodically reevaluates 

pesticides to ensure that as change occurs, products in the marketplace can be used safely. 

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

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

evaluation to determine whether chlorsulfuron continues to meet the FIFRA standard for 

registration. This problem formulation for the environmental fate and ecological risk assessment 

chapter in support of the Registration Review is intended for the initial docket opening the public 

phase of the review process. 

3. Conclusions from Previous Risk Assessments

The Agency has conducted multiple ecological risk assessments on chlorsulfuron that serve as a 

basis for this Problem Formulation, including the most recently completed ecological risk 

assessment written in support of the Reregistration Eligibility Decision (RED) (Kiernan and 

Young, 2005, DP330621). The previously evaluated uses include aerial and ground applications 

to cereal grains (wheat, oats, and barley), pasture and rangeland, and fallow land. Ground 

applications were evaluated for lawns, ornamental turf, sod farms, and non-cropland, such as 

roadway rights-of-way, airports, and other areas. The highest seasonal application rate evaluated 
7

was for ground applications to ornamentals and turf (0.25 lbs a.i./acre applied twice a year). The 

highest aerial application rate evaluated was for pasture and rangeland (0.0625 lbs a.i./acre/year). 

The labels did not specify a maximum number of applications or reapplication interval. 

Exposure was estimated for parent chlorsulfuron only, in the standard EPA farm pond using the 

Pesticide Root Zone Model coupled with the Exposure Analysis Model System (PRZM and 

EXAMS). Based on model output and because of chlorsulfuron’s low degradation rate,

chlorsulfuron concentrations in water were estimated to continually increase over the simulation 

period and chronic and peak concentrations were all nearly identical for all scenarios tested. The 

maximum one in ten year peak, 21-day average, and 60-day average concentrations in water 

were all 9.5 μg/L. 

Risk Summary for Chlorsulfuron from EFED’s 2005 Risk Assessment

Based on a screening-level [deterministic] risk assessment, risk quotients for terrestrial 

and aquatic animals do not exceed either acute or chronic risk levels of concern [LOCs] 

at current maximum application rates; however, LOCs for risks to nontarget terrestrial 

and aquatic plants are exceeded by orders of magnitude. [Screening level RQs for listed 

aquatic and terrestrial plants ranged from 18 to 580.] In regions where chlorsulfuron 

has been used regularly, chlorsulfuron concentrations in ground and surface irrigation 

water may result in damage to agricultural crops that are sensitive to chlorsulfuron. 

Additionally, uncertainty was identified regarding the potential effects that drift may have 

on fruit development in nontarget plant communities.1

Because LOCs for plants are exceeded, indirect effects to all listed species have the potential to

occur.

Chlorsulfuron Spray Drift onto Non-Target Terrestrial Plants

In 2005, EFED conducted a refined spray drift assessment to better characterize the potential risk 

to non-target plants at varying distances from a chlorsulfuron-treated field. The results of the

assessment indicate that while the extent of potential risk depends on the application rates and 

environmental conditions, almost all of the exposure scenarios indicate the potential for adverse 

effects to plants hundreds of feet from chlorsulfuron-treated fields.

Drinking Water Assessment

A drinking water assessment was completed at the same time that the RED ecological risk 

assessment was completed for chlorsulfuron (Kiernan and Young, 2005, DP330621). Drinking 

water exposure was evaluated for use on wheat and turf. Estimated drinking water 

concentrations (EDWCs) in surface water were estimated using PRZM/EXAMs. The Screening 

Concentration in Ground Water (SCIGROW) model was used to estimate exposure to residues in 

ground water. Table 1 provides details on the reported EDWCs. A drinking water assessment 

for the highest current use pattern2

 has not been conducted.

 1 (J.S. Fletcher et al., 1993) 2 According to the EFED Label Data Report completed on 08/03/2012, the highest current use pattern has a single 
8

Table 1. Previously Estimated Drinking Water Concentrations for the Human Health Risk 

Assessment

Use

Estimated Drinking Water Concentration (μg chlorsulfuron/L water)

Surface Water Ground Water Peak Annual Mean

Wheat1

0.023 lbs a.i./A 0.95 0.25

Turf2

0.0625 lbs a.i./A 1.9 0.96 1.6

1 A PCA of 0.57 was used with the surface water EDWC. 2 A PCA of 0.87 was used in the surface water EDWC.

4. Mechanism of Action

Chlorsulfuron is a sulfonylurea herbicide (Wood, 2009). It is a systemic pre or post-emergence

herbicide used to control both grass and broadleaf weeds, and is registered for use on agricultural 

and nonagricultural crops. Its mode of action in plants is through inhibition of the enzyme 

acetolactate synthetase (ALS) which results in inhibition of branched chain amino acid 

biosynthesis (Ware and Whitacre, 2004). Inhibition of this enzyme blocks biosynthesis of the 

branch chain amino acids valine, leucine, and isoleucine involved in plant growth and leads to 

plant death. 

5. Overview of Pesticide Usage

Chlorsulfuron was first registered in 1982 by DuPont under a Section 3 registration for use on 

wheat, barley and forage grasses and non-cropland grasses and tree plantings (USEPA, 2005). 

Chlorsulfuron is formulated in 36 active end-use products and is formulated as a flowable 

concentrate, granular, and water dispersible granular. Twenty-two co-formulated products

containing chlorsulfuron also have one of the following active ingredients: aminocyclopyrachlor, 

flucarbazone-sodium, metsulfuron, sulfentrazone or sulfometuron. Application methods include 

broadcast, low volume ground spray, soil and spot treatment, handguns, boom sprayers, 

backpacks, and/or hand held sprayers. It may be applied using aerial and ground application 

methods. Application method timings include fallow, preplant, postplant, and postemergence. 

The chemical profile produced by the Office of Pesticide Programs’ Biological and Economic 

Assessment Division (BEAD) (Ratnayake et al., 2012) and Label Use Information System 

(LUIS) tables, located in the docket, lists the use patterns of maximum exposures for the current 

uses of chlorsulfuron.

 application rate of 0.14 lbs a.i./A, the maximum number of applications, minimum retreatment interval, and the 

maximum annual application rate per acre are not specified. Use sites allowing this application rate include airports, 

landing fields, commercial and industrial lawns, commercial storage/warehouses premises, industrial outdoor 

construction areas, intermittently flooded areas/water, nonagricultural rights of ways/fencerows/hedgerows,

nonagricultural uncultivated areas, sewage disposal areas, and dry swamps/marshes/wetlands/stagnant water.
9

Currently registered uses include agricultural and non-agricultural use sites as described below:

Agricultural Use Sites

Mung beans, barley, field corn, oats, proso millet, safflower, sorghum, soybeans, triticale, wheat, 

cotton, pastures, rangeland, forage and fodder grasses, farm yards and uncultivated agricultural 

areas.

Non-Agricultural Use Sites

Ornamental lawns and turf, ditch banks, flood plains (dry), intermittently flooded areas (dry), 

swamps/marshes/bogs/standing water (vegetation)3, waterway edges and non-agricultural 

uncultivated areas/soils (airports, fencerows, military installations, rights-of-way, walkways, 

paths, etc.). 

The Appendix A Label Data Report (dated 08/03/2012) (dated 08/03/2012) is available in the 

docket and provide more detailed information on currently registered use patterns. According to 

the EFED Label Data Report completed on 08/03/2012, the highest current use pattern has a 

single application rate of 0.14 lbs a.i./A, the maximum number of applications, minimum 

retreatment interval, and the maximum annual application rate per acre are not specified. Use 

sites allowing this application rate include airports, landing fields, commercial and industrial 

lawns, commercial storage/warehouses premises, industrial outdoor construction areas, 

intermittently flooded areas/water, nonagricultural rights of ways/fencerows/hedgerows, 

nonagricultural uncultivated areas, sewage disposal areas, and dry 

swamps/marshes/wetlands/stagnant water. The labels do not have language that prohibits aerial 

applications and it is assumed that aerial applications may occur. The lowest reported maximum 

single application rate is 0.0078 lb a.i./A, with a maximum of 1 application per crop cycle is for 

use on wheat and barley. The corresponding minimum retreatment interval is not specified and 

the maximum annual application rate is 0.0625 lb a.i./A. There are higher maximum application 

rates for wheat and barley on other labels and some only include the maximum single application 

rate and lack information on the maximum number of applications, maximum annual application 

rate and minimum retreatment interval.

Based on the BEAD chemical profile (Ratnayake et al., 2012), the majority of chlorsulfuron 

applied to agricultural areas is applied to winter wheat (~95%). Smaller percentages (~2%) are 

applied to spring wheat and pastureland. Usage on nonagricultural crops is not quantified and 

reported on in the BEAD chemical profile.

Based on the BEAD chemical profile, labels for chlorsulfuron allow for use in agricultural 

uncultivated areas and non-agricultural uncultivated areas. A clear definition of what sites are 

included or excluded based on these terms is needed. Unclear label terminology could lead to 

use of chlorsulfuron on areas that are not intended use sites. Information on more specific use 

sites would allow a more refined/precise risk assessment. Defining use sites is important in 

determining where a product may be used, and which endangered species may be in proximity to 

locations of potential uses of chlorsulfuron.

Some labels include the following statements or similar statements in the general information 

 3 These uses do not include applications directly to water.
10

section:

“Some of these sites contain temporary pools of surface water as a result of site management. 

Use this product to treat intermittent drainage, intermittently flooded low lying sites, seasonally 

dry flood plains and transitional areas between upland and lowland sites when no water is 

present. In addition, apply this product to bogs, marshes, and swamps after water has receded 

and to seasonally dry flood deltas. Do not make applications to natural or man-made bodies of 

water such as canals, lakes, ponds, reservoirs, and streams.”

After applications to these areas, chlorsulfuron could potentially be introduced into water when 

water levels rise. More information on these uses (both on labels and what are the current 

practices) would improve the ability to predict potential exposure in aquatic systems.

As a result of the potential risk to off-target plants from chlorsulfuron spray drift, some 

chlorsulfuron labels include a section highlighting spray drift management. 

6. Environmental Fate and Transport

Chlorsulfuron will enter the environment via spray applied directly onto soil and foliage. It may 

move off-site via spray drift, leaching, and runoff. Chlorsulfuron may be applied to areas where 

flooding may occur after the application, and may also be introduced into water bodies when 

water levels rise and come into contact with soil containing residues of chlorsulfuron.

Table 2 summarizes the identity information and physical-chemical properties of chlorsulfuron. 

Chlorsulfuron has a log dissociation constant (pKa) of 3.4 and is a weak acid indicating it will 

primarily exist as a negatively charged ion (anion) in the natural environment. Its solubility 

increases with pH (587 mg/L at pH 5 and 3,380,000 mg/L at pH 7). Chlorsulfuron is considered 

non-volatile from dry non-adsorbing surfaces, water, and moist soil (OPPTS4 Guideline 

835.6100 classification). Based on chlorsulfuron’s log octanol-water partition coefficient (KOW) 

values of -1.41 to 0.34 and log octanol-air partition coefficient (KOA) values of -12.2 to -15.9, it 

is not likely to bioconcentrate in aquatic or terrestrial organisms. 

Table 2. Summary of physical-chemical properties of chlorsulfuron1

Parameter Value and Units Source and/or Comment

PC Code 118601 (USEPA, 2012c)

CAS Number CAS 64902-72-3 (USEPA, 2012c)

SMILES Code C1=CC=CC(=C1[S](NC(NC2=NC(=NC(=N2

)C)OC)=O)(=O)=O)Cl (USEPA, 2012c)

Chemical Name 1-(2-chlorophenyl)sulfonyl-3-(4-methoxy-6-

methyl-1,3,5-triazin-2-yl)urea (IUPAC) (USEPA, 2012c)

Empirical Formula C12H12ClN5O4S (USEPA, 2012c)

Molecular Weight 357.77 g/mole calculated

 4 Office of Prevention, Pesticides, and Toxic Substances (OPPTS) is now the Office of Chemical Safety and 

Pollution Prevention (OCSPP); however, some guidelines still reference OPPTS.
11

Parameter Value and Units Source and/or Comment

UV/Visible 

Absorption

No absorbance maxima was observed above 

290 nm MRID 47179901

Water Solubility pH 5 at 25o

C: 587±18.7 mg/L

pH 7 at 25o

C: 3,180,000 mg/L MRID: 42454104 (Gregg, 2008)

Vapor Pressure 2.3×10-11 Torr at 25oC MRID: 42454105 and identical 43898601; 

Non-volatile under field conditions

Henry’s Law 

constant

pH 5: 1.71×10-14 atm-m3/mol

pH 7: 3.15×10-18 atm-m3/mol

Estimated from vapor pressure

and water solubility at 25oC.

Dissociation 

Constant (pKa) 3.4 weak acid (Gregg, 2008)

Octanol-water 

partition coefficient 

(Kow)

pH 5 at 25oC: 2.19 and 2.07 (log KOW~0.34)

pH 7 at 25oC: 0.110 and 0.0947 (log KOW~-

0.95)

pH 9 at 25oC: 0.0387 (log KOW~-1.41)

MRID: 42454107

Not likely to bioconcentrate

Air-water partition 

coefficient (KAW)

pH 5: 6.98 × 10-13 (log KAW = -12.2)

pH 7: 1.29 × 10-16 (log KAW = -15.9)

Non-volatile from water surface.

Estimated from vapor pressure

and water solubility at 25oC.

Octanol-air partition 

coefficient (KOA)

pH 5: 1.4×108 (log KOA = 12.5)

pH 7: 8.54×10-14 (log KOA = 14.9)

Estimated from KAW and KOW. Unlikely to 

accumulate in terrestrial organisms due to low 

log KOW.

2

Cwater+soil/Cair pH 7: 8.4×1015

Estimated from KAW, ratio of soil/weight of 

water (r) of 6, and measured KF of 0.91 L/kg 

which was assumed to be equivalent to the Kd

value. Nonvolatile from moist soil 1

All estimated values were estimated according to “Guidance for Reporting on the Environmental Fate and 

Transport of the Stressors of Concern in Problem Formulations for Registration Review, Registration Review Risk 

Assessments, Listed Species Litigation Assessments, New Chemical Risk Assessments, and Other Relevant Risk 

Assessments” (USEPA, 2010). 2 A recent scientific advisory panel (SAP) reported, “Gobas et al (2003) concluded that chemicals with a log KOA > 

5 can biomagnify in terrestrial food chains if log KOW >2 and the rate of chemical transformation is low. However, 

further proof is needed before accepting these limits without reservations” (USEPA, 2009c). This was also 

supported by Armitage and Gobas’s work completed in 2007 (Armitage and Gobas, 2007). 

Table 3 summarizes abiotic and biotic transformation data. The range of half-lives for 

chlorsulfuron in soil and water indicates that it is persistent to very persistent (Toxic Release 

Inventory Classification) with half-lives ranging from 13 days to stable (Table 3) (USEPA, 

2012a). Hydrolysis is the primary mechanism of degradation at low pH. However, in neutral and 

alkaline environments, biodegradation is expected to dominate as pH increases and chlorsulfuron 

becomes less susceptible to hydrolysis. 

Chlorsulfuron is stable to hydrolysis except at acidic pH where the half-life is 22-23 days at 25o

C

(MRID 42156701). It is stable to aqueous photolysis and degrades slowly via soil photolysis

(half-lives ranged from 138-183 days in one clay loam soil; MRID 42156702). 

Only supplemental data are available on aerobic soil metabolism, for which available half-lives 

range from 60 to 299 days in eight soils (Table 3). Unextracted and unidentified residues were 

present in some soils and it was unknown whether these residues were a residue of concern; 

additionaly data on the extraction efficiency were not available and exhaustive extractions were 
12

not completed. Therefore, degradation kinetics were calculated assuming that unidentified and 

unextracted residues were a residue of concern. Submitted aquatic metabolism data are not 

considered valid. Anaerobic soil metabolism and aerobic aquatic metabolism data were not 

submitted. 

Table 3. Abiotic and Biotic Transformation of Chlorsulfuron

Parameter Calculated DT50 or Half-life

(days)1

Source (Study 

Classification) Comments

Hydrolysis

SFO linear regression,1 24±1oC:

pH 5 at 25oC: 22.4-23.1 days (SFO)

pH 7 at 25oC: Stable

pH 9 at 25oC: Stable

MRID 42156701 

same as 

41408102

Acceptable

SFO linear regression,1 20oC:

pH 4 at 20oC: not stable

pH 7 at 20o

C: Stable

pH 9 at 20oC: Stable

MRID 00035270

no DER

Study not consistent with guideline 

(Garner, 1980).

Atmospheric 

Degradation

Hydroxyl radical reaction rate:

4 days (estimated)

Estimated Using 

EPIWeb Version 

4.1 see Appendix 

A.

- Assumed 12-hour day; 1.5×106 OH 

molecules/cm3 using EPIweb 

version 4.1 (USEPA, 2009b)

- Chlorsulfuron is considered 

nonvolatile and thus little is 

expected to volatilize into air. The 

small amount that does volatilize 

may undergo long range transport in 

air.2

Aqueous 

Photolysis

24±1oC

Stable (pH 5, 7, 9)

MRID 42156702 

same as

41408101 

Acceptable

Soil 

Photolysis

SFO linear reg. 25±5o

C1, pH 8.0:

138 days, clay loam, triazine label

183 days, clay loam, phenyl label

MRID 41721001; 

duplicate of 

42156703

Acceptable

Calculated for 52oN latitude.

Aerobic Soil 

Metabolism3

SFO linear reg1, temperature NR:

60 days, silt loam, pH 6.0

60 days, sandy loam, pH 6.4 00035273

Supplementalnot for use in 

modeling

- May not be used to fulfill guideline. 

- Maintained in a greenhouse and the 

temperature was not held constant. 

- Soil was sieved with 0.157 inch 

screen, soil moisture 20-80% water 

holding capacity, not conducted in 

dark, mass balance low. 

25oC

0.1 mg/kg silt loam, pH 6.4

13.0 (IORE) and 17.3 (SFO) parent

13.4 (IORE) and 22.4 (SF) 

parent+unext

299 (SFO) parent+unext+unident

1.0 mg/kg silt loam soil, pH 6.4

12.1 (SFO) parent

12 (IORE) and 13 (SFO), 

parent+unext

Stable, parent+unext+unident

MRID 00035275

duplicates of

00086814

00083950

SupplementalMay be used in 

modeling 

depending on 

what other data 

are available5

- May not be used to fulfill guideline. 

One ring labeled. One replicate. No 

raw data. Degradates not followed. 

- Data were available at two 

concentrations in one soil. For 

modeling, the longest value 

recommended for model input 

across the concentrations will be 

used as the value to be used to 

estimate a representative model 

input value for that soil using the 

NAFTA guidance4

.
13

Parameter Calculated DT50 or Half-life

(days)1

Source (Study 

Classification) Comments

Anaerobic 

Soil 

Metabolism

No data submitted -- --

Aerobic 

Aquatic 

Metabolism

No data submitted -- --

Anaerobic 

Aquatic 

Metabolism

SFO linear, 25oC:

445 days, PA, pond, pH 5.6, tri

170 days, PA, pond, pH 5.6, phe

66 days, Alberta, pond, pH 8.4, phe

86 days, NE, pond, pH 8.3, phe

47 days, IL, pond, pH 5.0, phe

MRID 42156704 

update to 

00086815

Supplementalnot for use in 

modeling

- May not be used to fulfill guideline. 

- Alfalfa added to test system. 

- Rates were faster in sterile controls 

in the PA ponds suggesting that 

degradation was not mediated by 

microbes. 

Abbreviations: ECM=Environmental Chemistry Method; ILV=Independent Laboratory Validation; SFO=Single 

First Order; NA: Not Applicable; unext=unextracted; unident=unidentified; reg=regression 1 DT50 values were calculated using linear regression and the single first order equation or nonlinear regression and 

single first order (SFO), double first order in parallel (DFOP), or indeterminate order equations (IORE). An SFO 

value is reported for all studies. In addition, an IORE value was reported when that was the recommended model 

based on “Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media” dated December 

21, 2011, available at http://www.epa.gov/oppfead1/international/naftatwg/guidance/degradation-kin.pdf (accessed 

11/15/2012). The value used to estimate a model input value is a calculated SFO DT50, TIORE, or the slow DT50

from the DFOP equation. The values in this table do not necessarily reflect the values that will be used to estimate a 

model input value.

2 The minutes of the Scientific Advisory Panel examining issues related to persistent, bioaccumulative, and toxics 

states, “To protect against long range transport, a two-day degradation half-life in air is used internationally in 

regulations that identify persistent chemicals.” (USEPA, 2009c) 3 MRID 42214201 is an aerobic soil metabolism study that summarizes many studies including MRID 00035273. 

All studies were determined to be unacceptable, except MRID 00035273, which was reviewed under MRID 

00035273. 

4 When the SFO model does not fit the data well (as determined by the Guidance for Evaluating and Calculating 

Degradation Kinetics in Environmental Media available at 

http://www.epa.gov/oppfead1/international/naftatwg/guidance/degradation-kin.pdf), a first estimate of the 

representative half-life for modeling is made by calculating TIORE. TIORE is the half-life of a SFO model that passes 

through a hypothetical DT90 of the Indeterminate Order Rate Equation (IORE) fit. An additional fit of the Double 

First Order in Parallel (DFOP) is also determined. The shorter of TIORE versus the DFOP slow rate half-life is used 

as the representative value for modeling. If these values are the only data available for modeling, the value for this 

one soil will then be multiplied by three to account for the uncertainty in aerobic soil metabolism (NAFTA, 2012). 5 These data are supplemental and additionall data are requested because these data may not be used to fulfill the 

guideline. However, in the absence of additional data, these data may be used in estimating exposure as they are the 

only data available. Mass balances were low at only a couple of sampling points (87%) and unidentified residues 

were high (up to 48%). If these data were used in modeling, assumptions would be made to ensure that the use of 

these data were conservative.

Chlorsulfuron is classified as mobile to highly mobile with Freundlich organic carbon 

normalized soil-water distribution coefficients (KFOC) values ranging from 8 to 31 (mg/L)(mg/kg)-

1/n measured in four soils (MRID 42156705; Table 4)

5

. It has the potential to move to ground 

water. Based on chlorsulfuron’s water solubilities and pKa value, its affinity to organic materials 

(and thus organic carbon partition coefficient, KOC) is expected to decrease with increasing pH. 

 5 MRID 42214202 and 43421401 are classified as supplemental because the identity of the radioactivity was not 

determined. Using the lowest available degradation half-life, it was determined that at least 95% of the radioactivity 

should be the parent. Therefore, additional data on sorption coefficients were not requested.
14

Table 4. Summary of Submitted Sorption Studies of Chlorsulfuron (MRID 42156705)2

Soil, texture % 

sand

% 

silt

% 

clay

% 

OC

soil 

pH

KF

(mg/L)(m

g/kg)-1/n

1/n

KFOC

(mg/L)(mg/

kg)-1/n

Chlorsulfuron 

concentration in 

water (mg/L)1

Madera, 

loam 48 35 17 0.46 8 0.28 0.9 35 0.15 – 4.53

Woodstone, 

sandy loam 60 33 7 0.64 6.6 0.09 0.85 8 0.17 – 5.31

Keyport, silt 

loam 20 39 21 1.1 5.7 0.38 0.88 20 0.13 – 4.3

Flanagan, silt 

loam 2 81 17 2.5 5.4 0.91 0.91 21 0.09– 3.06

1 The sorption coefficients are applicable over the range of equilibrium chlorsulfuron concentrations in water over 

which the coefficients were measured.

2 Values of Kd and KOC values were not calculated for this study. Values of Kd and KOC may be calculated and used 

in modeling for a future assessment.

In 15 supplemental field lysimeter studies, estimated dissipation half-lives ranged from 16 days 

to 210 days (MRID 42214202 and 43421401). Leaching of chlorsulfuron was observed, with 

detections at depths up to 38 cm. Residues observed in these field studies include parent 

chlorsulfuron, chlorosulfonamide, triazine amine, hydroxyl triazine amine, ring-opened 

chlorsulfuron, 2-chlorophenylsulfonylurea, o-desmethylchlorsulfuron, and triazine urea 

The environmental fate database is not complete, and the information on transformation products 

may change with the receipt of additional fate data. The following eight transformation products 

were observed in environmental fate studies: 

• O-desmethylchlorsulfuron (2-chloro-N-[[(4-hydroxy-6-methyl-1,3,5-triazine-2-yl)-

amino)carbonyl]benzenesulfanamide; ODMC)

• ring-opened chlorsulfuron (1-(2-chlorophenylsulfonyl)-7-acetyltriuret; ROC)

• chlorosulfonamide (2-chlorobenzenesulfanamide; CSM)

• triazine amine (2-amino-4-methoxy-6-methyl-1,3,5-triazine; TA)

• hydroxyl triazine amine (4-hydroxy-6-methyl-1,3,5-triazine-2-amine; OHTA)

• dihydroxy triazine (2,4-dihydroxy-6-methyl-1,3,5-triazine; DT)

• 2-chlorophenylsulfonylurea (2-chloro-N-(aminocarbonyl)benzenesulfanamide; CPSU)

• triazine urea (TU)

The following degradation products were hypothesized as potential transformation products by 

study authors:

• acetylbiuret (1-acetylbiuret)

• o-desmethyl triazine amine (ODMTA)

• 5-hydroxychlorosulfanamide (2-chloro-5-hydroxybenzenesulfanamide; OHCSM)

• 5-hydroxychlorsulfuron (2-chloro-5-hydroxy-N-[(4-methoxy-6-methyl-1,3,5-triazin-2-

yl)aminocarbonyl] benzenesulfonamide; OHCSF)
15

Figure 1. Potential Degradation Pathway of Chlorsulfuron Based on Degradates Obserbed 

in Laboratory and Field Studies

Purple and bold values were present at greater than 10% of applied radioactivity in laboratory studies and the 

asterisk indicates the compound was observed in a lysimeter study. Residues that were not major but were 

observed in lysimeter studies are blue. Abbreviations are defined in text above figure.

There were five major degradates observed in the environmental fate laboratory studies: odesmethylchlorsulfruon, chlorosulfonamide, triazine amine, ring-opened chlorsulfuron, and 2-

chlorophenylsulfonylurea.

6

 Dihydroxy triazine was present at its maximum of 9% at the end of 

the hydrolysis study (pH 5 only). Had the study continued for longer, it seems likely that 

dihydroxy triazine would have been found to be a major degradate. Table 5 shows the 

maximum amount of applied radioactivity for each identified transformation product and 

corresponding study type. Many of the maximum values were observed at the final sampling 

interval. Residues observed in field studies include the major residues observed in the laboratory 

studies (o-desmethyl chlorsulfuron, chlorosulfonamide, triazine amine, ring-opened 

chlorsulfuron, and 2-chlorophenylsulfonylurea) and two residues not observed in laboratory 

studies (triazine urea and hydroxy triazine amine). Soil column leaching studies suggested that 

chlorsulfuron was more mobile than chlorosulfonamide and triazine amine, except for 

chlorosulfonamide in a Keyport silt loam soil. MRID 46155803 examines sorption of triazine 

amine and is currently under review.

 6 Major degradates are those present at ≥10% applied parent equivalents.
16

Table 5. Summary of maximum amount of transformation products observed in fate 

studies.

Chlorsulfuron 

degradatesf

Maximum Degradate % of Applied Radioactivity Associated with Compound (Time of Peak)

Amount Detected at Final Sampling Interval in Corresponding Study

Hydrolysis Aqueous 

Photolysis Soil Photolysis Aerobic Soil Anaerobic Aquatic

Observed 

in 

Lysimeter 

Study

CSM*+ 33 (31 days)a,d 2 (31 days)a NR NA 14 (70 days)a Yes

ROC*+ 18 (31 days)a,e NR NR NA 31 (365 days)ab Yes

ODMC*+ 14 (21 days)

12 (31 days)d 1 (31 days)a 3 (74 days)a NA 31 (365 days)ab Yes

TA*+ 17 (31 days)a,d NR 6 (74 days) NA 21 (365 days)a Yes

CPSU* NA NA NA NA 14 (56 days)a Yes

TU+ NA NA 8 (74 days) NA NR Yes

OHTA NA NA NA NA NR Yes

DT 9 (31 days)a,e NR 1 (74 days) NA No

OHCSF NA NA NA NA NA NA

ODMTA NA NA NA NA <0.1 (all days) No

OHCSM NA NA NA NA <0.1 (all days) No

AB NA NA NA NA NA No

Abbreviations: NA=not analyzed; ND=not determined; NR=not reported a Peak at final sampling interval in some studies. b Polar compounds were identified as either ODMC or ROC in the anaerobic aquatic study.

c See Appendix H for more information on source of information in this table. d Observed at more than one pH but only major at pH 5.

e Observed at pH 5 only.

f Bold values with asterisk indicate the degradate is a major degradate. A plus (+) sign indicates that toxicity data 

are available for the degradate (see Appendix I).

6.1. Monitoring Data

The following databases and sources were searched for monitoring information on chlorsulfuron 

on August 2, 2012:

• The United States Geological Survey (USGS) National Water-Quality Assessment 

(NAWQA) Program Data Warehouse 

(http://infotrek.er.usgs.gov/traverse/f?p=NAWQA:HOME:1405517206944567)

• The USGS National Stream Quality Accounting Network (NASQAN) program 

(http://water.usgs.gov/nasqan/ )

• California Department of Pesticide Regulation (DPR) Surface Water Database 

(http://www.cdpr.ca.gov/docs/emon/surfwtr/surfdata.htm)

• California Environmental Data Exchange Network (CEDEN; http://www.ceden.org/)
17

No monitoring data are available, as none of the databases looked for chlorsulfuron in water. 

Records for chlorsulfuron were available in the Storet/WQX Data Warehouse 

(http://www.epa.gov/raf/publications/guidelines-ecological-risk-assessment.htm). These records 

will be completely reviewed when the risk assessment is completed.

6.2. Clean Water Act

Chlorsulfuron is not identified as a cause of impairment for any water bodies listed as impaired 

under section 303(d) of the Clean Water Act, based on information provided at 

http://iaspub.epa.gov/tmdl_waters10/attains_nation_cy.cause_detail_303d?p_cause_group_id=88

5. In addition, no Total Maximum Daily Loads (TMDL) have been developed for the herbicide, 

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. More information on impaired water bodies and 

TMDLs can be found at http://www.epa.gov/owow/tmdl/.

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.

Aquatic life benchmarks for chlorsulfuron are reported in Table 6. The correct benchmark for 

nonvascular aquatic plants (50 μg a.i./L) should replace the previous value which was 

erroneously reported as 0.055 μg a.i./L due to a conversion error. Aquatic Life Benchmarks, 

developed by OPP for baseline risk assessments, are estimates of the concentrations below which 

pesticides are not expected to harm aquatic life. Each Aquatic Life Benchmark is based on the 

most sensitive, scientifically acceptable toxicity endpoint available to EPA for a given taxon (for 

example, freshwater fish) of all scientifically acceptable toxicity data available to EPA 

multiplied by the corresponding level of concern of 0.5 for acute endpoints and 1.0 for chronic 

and plant endpoints. Aquatic life benchmarks may be found at 

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm. 

Table 6. OPP Aquatic Life Benchmarks for Chlorsulfuron in μg a.i./L1

Fish Aquatic Invertebrates Nonvascular 

Plants

Vascular 

Plants

Office of Water Aquatic 

Life Criteria

Acute Chronic Acute Chronic Acute Acute Maximum 

Conc.

Continuous 

Conc.

>125,000 32,000 >185,000 20,000 50 0.35 -- -- 1 The benchmarks at http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm are currently incorrect 

and will be updated to be consistent with what is reported in this document.
18

7. Receptors

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

assessment will rely 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 to potential effects on a variety of species (receptors) included under these 

taxonomic groupings. The most sensitive endpoint for each taxon is evaluated. Assessment 

endpoints include direct toxic effects on the survival, reproduction, and growth of terrestrial and 

aquatic life, as well as indirect effects, such as reduction in prey base and/or modification of 

habitat. The evaluated taxa include freshwater fish, freshwater aquatic invertebrates, birds, small 

mammals, terrestrial invertebrates, algae, and terrestrial plants.

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

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

aquatic and terrestrial receptors. These data include studies on the technical grade active 

ingredient, degradates, and formulated products (e.g. “six-pack” acute toxicity studies). The open 

literature studies are identified using EPA’s ECOTOX database, which employs a literature 

search engine for locating chemical toxicity data for aquatic life, terrestrial plants, and wildlife 

(USEPA, 2009a). The evaluation of both sources of data can also provide insight into direct and 

indirect effects of chlorsulfuron on biotic communities from loss of species that are sensitive to 

the chemical, and from changes in structure and functional characteristics of affected 

communities.

Other sources of information, including use of the acute probit dose-response relationship to

establish the probability of an individual effect and the Ecological Incident Information System 

(EIIS), are consulted to further refine the characterization of potential ecological effects 

associated with exposure to chlorsulfuron. A summary of the currently available ecotoxicity 

information and the incident information for chlorsulfuron are provided below. 

Table 7 provides a summary of the most sensitive surrogate species tested to characterize the 

potential acute and chronic ecological effects of chlorsulfuron. Some of the values in the table 

below have been revised since the last risk assessment based on a re-evaluation of DERs for 

chlorsulfuron for this problem formulation.

Table 7. Most Sensitive Species Evaluated for Potential Ecological Effects from

Chlorsulfuron.

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

Birds1

Acute 

(Dose-based)

Bobwhite Quail 

(Colinus virginianus)

LD50 >5,000 mg a.i./kgbw Acute000352-63

(Acceptable)

Practically 

non-toxic

Acute 

(Dose-based)

Mallard Duck

(Anas platyrhynchos)

LD50>5,000 mg a.i./kgdiet

Acute000352-66 

(Acceptable) Practically 

non-toxic
19

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

Chronic Bobwhite Quail 

(Colinus virginianus)

NOAEC = 174 mg a.i./kgdiet

LOAEC (reproduction)

= 961 mg a.i./kg-diet

Other sublethal effects

One-Generation 

Reproduction 426340-

01

(Acceptable)

--

Mammals

Acute

Laboratory Rat 

(Rattus norvegicus)

LD50>5,500 mg a.i./kg-bw Acute000314-06

(Acceptable)

Practically 

Non-toxic

Chronic

NOAEL = 100 mg/kg-diet

LOAEL (decreased bw in 

males) = 500 mg/kg-diet

2-Year 

Chronic000860-03

(Acceptable)

--

Insects

Acute (contact) Honey Bee 

(Apis mellifera) LD50>25 μg a.i./bee

48-Hour

421299-02

(Acceptable)

Practically 

Non-toxic

Freshwater fish2

Acute

Rainbow Trout

(Oncorhynchus 

mykiss) 

LC50>300 mg a.i./L

96-Hour 

000352-58

(Acceptable)

Practically

Non-toxic

Chronic

NOAEC

= 32 mg a.i./L

LOAEC (length) 

= 66 mg a.i./L

Other sublethal effects

77-Day Early Life 

Stage

419764-05

(Acceptable)

--

Freshwater Invertebrates

Acute

Water Flea (Daphnia 

magna)

EC50>370 mg a.i./L 48-Hour

000352-62

(Acceptable)

Practically 

Non-toxic

Chronic

NOAEC

= 20 mg a.i./L

LOAEC (reproduction) 

=36 mg/L

21-Day

419764-04 and 

419764-08

(Supplemental)3

--

Estuarine/Marine Fish

Acute Sheepshead Minnow 

(Cyprinodon 

varigatus)

LC50>980 mg a.i./L

96-Hour

419764-01 

(Acceptable)

Practically 

Non-toxic

Chronic -- -- ---

Estuarine/Marine Invertebrates

Acute

Mysid 

(Americamysis

bahia)

LC50>89 mg a.i./L

96-Hour

419764-02

(Acceptable)

Slightly toxic

Terrestrial Plants

Monocot Onion

(Allium cepa)

EC25 (dry wt) = 

3 x 10-4 lb a.i./A

----

NOAEC (dry wt) = 

4.5 x 10-5 lb a.i./A

Tier 2 Seedling 

Emergence

463618-01

(Supplemental)

4

NA

EC25 (dry wt) = 

2.2 x 10-5 lb a.i./A

----

EC05(shoot height) = 

2.6 x 10-6 lb a.i./A

Tier 2 Vegetative 

Vigor

463268-01

(Supplemental) 5

NA
20

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

Dicot

Pea 

(Pisum sativum)

EC25(dry wt) = 2.2 x 10-5 lb 

a.i./A

----

NOAEC = 1.8 x 10-4 lb 

a.i./A

Tier 2 Seedling 

Emergence

463618-01

(Supplemental) 4

NA

Rape

(Brassica rapa)

EC25 (dry wt) = 

1.0 x 10-5 lb a.i./A

----

EC05 (shoot height) = 

8.0 x 10-7 lb a.i./A

Tier 2 Vegetative 

Vigor

46578942 

(Supplemental) 5

NA

Aquatic Plants

Aquatic vascular 

Plants

Duckweed 

(Lemna gibba)

EC50 (dry wt) =

3.5 x 10-4 mg a.i./L

-------

NOAEC (frond no. and dry 

wt) =

2.4 x 10-4 mg a.i./L

14-Day Study

458329-01

(Supplemental)6

NA

Non-Vascular 

Aquatic Plants

Green Algae 

(Pseudokirchneriella 

subcapitata )

EC50 (cell density) =

0.05 mg a.i./L

-------

NOAEC (cell density) = 

0.0094 mg a.i./L

120-Hour

421868-01

(Supplemental)7

NA

1 Birds represent surrogates for terrestrial-phase amphibians and reptiles. 2 Freshwater fish may be surrogates for aquatic-phase amphibians. 3 The chronic daphnid study was classified as supplemental due to a number of deficiencies and deviations. 4 The seedling emergence study is classified as supplemental due to plant crowding in pots and low light conditions.

5 The vegetative vigor study is classified as supplemental due to lack of a defined dose response curve and low light 

conditions. An extrapolated EC05 was used in place of a NOAEC as the endpoint for chronic toxicity per EPA policy. 6 This study is classified as supplemental because the study was conducted as a static test. 7 This study is classified as supplemental as raw data were not available and the EC50 was calculated using nominal 

concentration values. This value was erroneously reported in the last risk assessment (Table 9) and in EPA’s Aquatic Life 

Benchmarks7 as 0.000055 mg a.i./L (Kiernan and Young, 2005, DP330621).

7.1. Effects to Aquatic Organisms

Summary 

Table 7 summarizes the most sensitive endpoints used in risk assessment for aquatic organisms. 

Based on these data, chlorsulfuron is characterized as practically non-toxic to freshwater and 

marine/estuarine fish on an acute exposure basis. Many of the acute toxicity endpoints are nondefinitive (i.e., “greater than” values) as no mortalities or effects were observed at the highest 

concentrations tested. Chlorsulfuron is considered practically nontoxic to freshwater 

invertebrates and slightly toxic to estuarine/marine invertebrates on an acute exposure basis. 

 7 Benchmarks, developed for baseline risk assessments, are estimates of the concentrations below which pesticides 

are not expected to harm aquatic life. Each Aquatic Life Benchmark is based on the most sensitive, scientifically 

acceptable toxicity endpoint available to EPA for a given taxon (for example, freshwater fish) of all scientifically 

acceptable toxicity data available to EPA multiplied by the corresponding level of concern of 0.5 for acute endpoints 

and 1.0 for chronic and plant endpoints. Aquatic life benchmarks may be found at 

http://www.epa.gov/oppefed1/ecorisk_ders/aquatic_life_benchmark.htm. 
21

Compared to aquatic animals, aquatic plants are orders of magnitude more sensitive to 

chlorsulfuron. The endpoints and concentrations from these studies will be used to assess risks to 

fish (and aquatic-phase amphibians for which fish serve as surrogates) and aquatic invertebrates 

from exposure to water containing chlorsulfuron residues from runoff and/or drift from treated 

areas. No data have been submitted on toxicity of degradates of chlorsulfuron to aquatic 

organisms.

Fish

Chlorsulfuron is practically non-toxic to both freshwater fish and estuarine/marine fish on an 

acute exposure basis. Chronic exposure of rainbow trout (Oncorhynchus mykiss) to chlorsulfuron 

resulted in a NOAEC of 32 mg a.i./L (LOAEC = 66 mg a.i./L) based on decreased growth 

(length), while a chronic study of sheepshead minnow (Cyprindon varigatus) resulted in a 

NOAEC of 980 mg a.i./L (LOAEC>980 mg a.i./L) based on decreased growth (length). 

Aquatic Invertebrates 

Chlorsulfuron is practically non-toxic to freshwater invertebrates, and is slightly toxic to 

estuarine/marine invertebrates on an acute exposure basis. Chronic exposure to chlorsulfuron 

resulted in a NOAEC of 20 mg a.i./L (LOAEC=36 mg a.i./L) for water flea (Daphnia magna) 

based on total decreased growth (length). A chronic toxicity study with marine/estuarine 

invertebrates is not available. 

Aquatic Plants

Studies were submitted for a freshwater vascular plant (duckweed, Lemna gibba), and for the 

nonvascular aquatic plant green algae (Pseudokirchneriella subcapitata, formerly called

Selenastrum capricornutum), a freshwater blue-green (cyanobacteria) algae (Anabaena flosaquae), a freshwater diatom (Navicula pelliculosa), and a marine diatom (Skeletonema costatum) 

exposed to the technical chlorsulfuron. 

Exposure of duckweed to chlorsulfuron technical resulted in an 7-day EC50 value of 0.35 μg 

a.i./L and a NOAEC of 0.24 μg a.i./L. These values will be used in assessing potential risks of 

chlorsulfuron to aquatic vascular plants. 

The most sensitive 96-hr EC50 value for nonvascular plants is 50 μg a.i./L; the associated 

NOAEC is 9.4 μg a.i./L for reductions in cell density. Green algae are the most sensitive aquatic 

nonvascular plants to chlorsulfuron. 

7.2. Effects to Terrestrial Organisms

Available ecotoxicity data indicate that chlorsulfuron is characterized as practically non-toxic to 

mammals and birds on an acute exposure basis and the compound is practically nontoxic to birds 

on an a subacute dietary exposure basis as well. Many of the acute toxicity endpoints are nondefinitive (i.e., “greater than” values) as no mortalities or toxic effects were observed at the 

highest levels tested. Compared to terrestrial animals, plants are orders of magnitude more 

sensitive to chlorsulfuron. The endpoints and concentrations from these studies will be used to 

assess risk to mammals and birds from direct application of chlorsulfuron to treated areas and 

from off-target spray drift. Table 7 summarizes the most sensitive endpoints used in risk 
22

assessment for terrestrial animals. No data have been submitted for degradates of chlorsulfuron 

on toxicity to terrestrial organisms.

The acute and chronic toxicity values associated with chlorsulfuron exposure to mammals, 

birds, and terrestrial plants are summarized in Appendix C. 

Mammals

A toxicity study in Norway rats (Rattus norvegicus) indicates that chlorsulfuron is practically 

non-toxic to rats on an acute oral exposure basis with an LD50 >5,500 mg/kg-bw, the highest 

dose tested (MRID 000314-06). 

A combined chronic/carcinogenicity study in rats was used by the Health Effects Division to 

select the dose and endpoint for establishing the chronic reference dose (for use in human 

exposure assessment). The NOAEL is 5 mg/kg/day or 100 mg a.i./kg-diet, and the LOAEL is 25

mg a.i./kg/day or 500 mg a.i./kg-diet, based on decreased body weight gain in females (MRID 

000860-03).

Birds

A study of acute toxicity in bobwhite quail (Colinus virginianus) indicates that chlorsulfuron is 

practically non-toxic to bobwhite quail on an acute oral exposure basis (LD50>5,000 mg 

a.i./kg-bw, highest dose tested). On a subacute dietary exposure basis, in mallard ducks (Anas 

platyrhynchos), chlorsulfuron resulted in an LC50>5,000 mg a.i./kg-diet, the highest dose tested

(MRID 000352-66). 

No treatment-related effects on adult bird mortality, food consumption, body weight, or 

reproductive parameters and no clinical signs or treatment-related effects in offspring survival or 

body weight were observed in studies of the chronic toxicity of chlorsulfuron for mallard duck or

bobwhite quail. The NOAEC for mallard duck is >961 mg a.i./kg-diet and 961 mg a.i./kg-diet for 

bobwhite quail (MRID 426340-01).

No chronic toxicity studies for chlorsulfuron formulations or chlorsulfuron degradates in avian or 

mammal species have been submitted. In the absence of other data, the toxicity data for birds 

serves as surrogate information for the effects of chlorsulfuron on reptiles and terrestrial-phase 

amphibians.

Terrestrial Invertebrates

Results of available toxicity studies indicate that chlorsulfuron is practically non-toxic to honey 

bees (Apis mellifera) on an acute contact exposure basis (LD50 >25 μg a.i./bee; MRID 000314-

06). 

Terrestrial Plants

Results of the seedling emergence study identify onion (Allium cepa) as the most sensitive 

monocotyledonous plant species and pea (Pisum sativum) as the most sensitive dicotyledonous

plants, with decreased dry weight as the most sensitive endpoint affected. The NOAEC and 

EC25 values of 0.000045 lbs a.i./A and 0.0003 lbs a.i./A, respectively, for onion, and 0.00018

lbs a.i./A and 0.000022 lbs a.i./A, respectively, for pea will be used to assess the effects of 
23

exposure to chlorsulfuron on seedling emergence in non-listed and listed terrestrial plants

(MRID 463618-01). 

Results of the Tier II vegetative vigor studies identify onion (Allium cepa) as the most sensitive 

monocot and rape (Brassica rapa) as the most sensitive dicot, with dry weight and shoot height

as the most sensitive endpoints affected for onion and rape, respectively. The EC05 (used in place 

of a NOAEC for listed species assessment) and EC25 values of 0.0000026 lbs a.i./A and 

0.000022 lbs a.i./A, respectively, for onion, and the EC05 and EC25 values of 0.0000008 lbs 

a.i./A and 0.00001 lb a.i./A, respectively, for rape were the most sensitive endpoints for

chlorsulfuron on vegetative vigor in non-listed and listed terrestrial plants (MRID 463268-01) .

A series of special studies on the reproductive toxicity of chlorsulfuron on soybeans (Glycine 

max) was submitted by DuPont and two studies were recently reviewed by EFED. Based on the 

results of the studies, it was concluded that the inhibitory concentration for 25% of the plants 

tested (IC25 or EC25) determined in a typical guideline vegetative vigor study (850.4150) is 

protective of inhibitory effects of exposure at reproductive stages. The studies were classified as 

acceptable (D404866). As a result of the analysis of this study, no further data for chlorsulfuron 

reproductive effects on terrestrial plants are needed for risk assessment purposes (MRID 487769-

02 and 487769-03). 

EFED's Plant Technical Team (PTT) conducted an analysis of available SU plant reproduction 

data from the open literature and the registrant-submitted data for chlorsulfuron and concluded 

that data from the 850.4150 vegetative vigor guideline study are sufficiently protective of 

potential impacts to plant reproduction. Acetolactate synthase (ALS) inhibitors primarily affect 

metabolically-active meristem tissues. When plants are exposed at a young, vigorously growing 

life-stage, effects are expressed primarily as inhibition of vegetative growth (i.e. biomass, shoot 

length). As plants mature these effects are less pronounced. However, as plants enter their 

reproductive life-stage, the metabolically-active tissue will include flower and seed production. 

Plants exposed to SU herbicides during the reproductive life stage are likely to exhibit adverse 

effects on reproduction, generally expressed as reduced seed number or reduced seed weight. 

Based on the latest data analysis, these effects are expected to occur at similar concentrations to 

those effects determined in the guideline vegetative vigor studies (850.4150) so further data are 

not requested at this time. 

7.3. Degradate Toxicity

Toxicity and risk from chlorsulfuron degradates is an area of uncertainty. There is an exposure 

concern for these degradates due to the potential mobility and formation rates relative to the 

parent chlorsulfuron. Degradates are discussed in more detail in Section 11, Stressors of 

Concern.

7.4. Ecological Incidents 

A preliminary review was made on August 13, 2012 of the Incident Data System (IDS) and the 

Ecological Incident Information System (EIIS, version 2.1.1), which are maintained by the 
24

Agency’s Office of Pesticide Programs, and the Avian Monitoring Information System (AIMS), 

which is maintained by the American Bird Conservancy. 

In addition to individual incidents recorded in EIIS, incidents may be 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” (W-B), “minor plant” 

(P-B), and “other nontarget” (ONT) incidents. “Other nontarget” incidents include reports of 

adverse effects to insects and other terrestrial invertebrates. For chlorsulfuron, 9 plant damage 

incidents were reported in the EIIS database (accessed July 19, 2012) and 7 separate aggregate 

incidents (6 plant damage) were reported in the IDS database (accessed August 13, 2012). No 

incidents involving birds have been reported for chlorsulfuron to the AIMS database (accessed 

August 13, 2012). A summary of plant incidences reported for chlorsulfuron is provided below.

As recently as September, 2011, plant damage was reported as a result of chlorsulfuron use. 

Incidents are reported in the Aggregate Incident Summary Report for chlorsulfuron for several 

recent years: 2011 (two reported incidents-both for plant damage), 2010 (three reported 

incidents-one for plant damage, two for wildlife), 2008 (one reported incident for plant damage) 

and 2003 (one reported incident for plant damage).

The EIIS contains nine incident reports. The most recent of these incidents (IO17719-001) 

occurred in July, 2006 in Shasta County, California, where 126 acres of an agricultural area were 

affected due to ‘possible’ exposure from chlorsulfuron. In June, 2006, in Whitman County, 

Washington, an agricultural area was affected by exposure to chlorsulfuron from a right-of-way 

spraying, although the incident is listed as “unlikely” (I021457-012). In April, 2004 in 

Multnomah County, Oregon, a right-of-way spraying of chlorsulfuron was considered 

“probable” and caused $40,000 of damage (I015576-001). In August, 2005 in Sutter County, 

California, more than 75 trees were damaged by a “probable” exposure to chlorsulfuron from a 

right-of-way treatment (I016671-001). 

In June 1998 in Benton County, WA, an orchard bound on three sides by dry land' wheat 

reported four years of reduced Bing cherry production (I013884-012). The Washington State

Department of Agriculture investigated, but the cause remains unknown and the investigation 

was not continued. Chlorsulfuron was one of the herbicides used on the wheat fields. Another 

incident occurred in 1997 (I0 13882-035), where potatoes were possibly affected by tank

contamination by chlorsulfuron near Walla Walla, WA. Also in 1997, leaf spots in cherry and 

apple orchards in Douglas County, WA were reported (I0 13 883-003). Chlorsulfuron and 2,4-D 

were used on nearby wheat fields and the spots were thought by investigators to be due to 

chlorsulfuron drift. In 1994, a farmer in KY reported damage to tobacco seedlings after 2,4-D 

and chlorsulfuron were used on a nearby road right-of-way (1001473-001). That the damage 

(chlorosis and growth cessation) was due to chlorsulfuron was determined to be "possible".

The last incident in the database (1000230-001) is reported to be from spring 1977 and was 

reported to the Agency in 1992. Peach trees in a Benton, WA orchard were severely damaged 

and cherry and prune trees were damaged to a lesser degree (pear trees were unaffected). It was 

determined that the damage was "definitely due" to chlorsulfuron, which had been applied to a 

nearby wheat field. The date of 1977 raised questions, as chlorsulfuron was not registered until 
25

1982. The incident was reported by George Abel, Pesticide and Toxic Substance Branch, US 

EPA, Region 101 1200 Sixth Avenue, Seattle, WA 98101. An investigation into this anomaly 

suggests that the correct date of this incident was likely 1987, according Cliff Weed, Compliance 

Program Manager, Pesticide Management Division, Washington State Department of 

Agriculture (personal communication, March 09, 2005). Weed, an employee since 1985, recalls 

that numerous incidents of crop damage, most allegedly due to chlorsulfuron, were investigated 

in the spring of, 1987. He specifically recalls an incident involving peaches; however, as the 

Department routinly discards records after seven years, no known records from that time exist.

The Horse Heaven Hills lawsuits are not in the Agency's EIIS database, but the alleged incidents 

of chlorsulfuron drift were investigated by Fletcher (1991). An orchard suffered several years of

reduced yield in the late 1980s in an area proximal to wheat farms at Horse Heaven Hills, where

herbicides were regularly used. While the reduced yields and plant damage were not noted 

before the use of chlorsulfuron in the area, the investigation results were inconclusive.

In the risk assessment, these databases will be checked again and any incidents reported will be 

further evaluated to determine if the reported incidents represent current patterns of use for 

chlorsulfuron. The absence of reported incidents should not be construed as the absence of 

incidents. Incident reports for non-target organisms typically provide information only on 

mortality events and plant damage. Sublethal effects in organisms such as abnormal behavior, 

reduced growth and/or impaired reproduction are rarely reported, except for phytotoxic effects in 

terrestrial plants.

8. Evaluation of Non-definitive Toxicity Values

Many of the acute terrestrial and aquatic animal studies resulted in non-definitive toxicity values, 

meaning that the actual toxicity of the compound is “greater than” the LC50, and thus, unknown. 

This evaluation is specific to the active ingredient as the data for the TGAI may not be 

representative or predictive of toxicity for the end-use product.

Aquatic Animals

In an effort to determine whether additional data are needed to evaluate risk to non-target aquatic 

fish and invertebrates, EFED conducted a comparison of the non-definitive toxicity value to the

estimated aquatic concentration (EEC). For acute exposure to listed aquatic organisms, the EEC 

would have to be 468 times higher than the previous EEC to approach a risk of concern for 

aquatic animals.

Birds and Mammals

For acute exposure to listed birds, the EEC would have to be 15 times higher than the previous 

EEC. For acute exposure to listed mammals, the EEC would have to be 20 times higher than the 

previous EEC. Therefore, the risk to birds and mammals is presumed to be low and additional 

data are not needed at this time.
26

9. Ecosystems Potentially at Risk

The ecosystems potentially at risk may be 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 down stream from the 

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

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

marine ecosystems, including estuaries. 

10. 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, 1998). For chlorsulfuron, the ecological entities include the following: birds, reptiles, 

terrestrial-phase amphibians, mammals, freshwater fish, freshwater aquatic-phase amphibians 

and invertebrates, estuarine/marine fish and invertebrates, terrestrial plants, insects, aquatic 

plants, and algae. The attributes for each of these entities include growth, reproduction, and 

survival. 

11. Identification of Stressors of Concern

The transformation products important for consideration for exposure include: 

• the major degradates and degradates observed in lysimeter studies (ring-opened 

chlorsulfuron, o-desmethylchlorsulfuron, 2-chlorophenylsulfonylurea, 

chlorosulfonamide, triazine amine), 

• degradates observed in lysimeter studies (hydroxy triazine amine and triazine urea), 

• and the minor degradate dihydroxy triazine. 

Dihydroxy triazine was observed at 9% applied radioactivity in the hydrolysis study at pH 5 on 

the final sampling interval and is assumed to be essentially a major degradate because if the 

study was continued it is possible that it would have been observed at 10% or higher applied 

radioactivity. All of these degradates are assumed to have the potential to occur in the natural 

environment and to have some potential for exposure. Appendix H provides structure, identity, 

and fate information on the transformation products. Other transformation products or higher 

percentages of transformation products could be observed in fate laboratory studies submitted in 

the future to address data gaps. These transformation products would have the potential to be 

observed in the environment based on registered uses. Valid aerobic soil and aerobic aquatic 

metabolism studies are not available and are particularly important studies in understanding the 

environmental fate and transformation products that are likely to be observed in the natural 

environment. 
27

Toxicity data on chlorsulfuron degradation products have not been submitted to EFED; however, 

data are available from other sources. These data were used to prioritize the residues of concern 

for ecological risk assessment. As these prioritizations were made based on unreviewed data, 

these determinations may be revisited when data are fully reviewed. It is recommended that 

these data be submitted to EFED to support the registration review of chlorsulfuron and to fully 

support determinations on the potential residues of concern for chlorsulfuron.

Residues of Concern for Drinking Water Consumed by Humans

The most recent drinking water assessment completed for chlorsulfuron was in support of the 

Tolerance Registration Eligibility Decision (TRED) and was completed in 2002 (Shanaman, 

2002, D266073). A Tier 1 risk assessment was completed. The only residue considered in the 

assessment was the parent chlorsulfuron. In 1995 the Health Effect Division (HED) Metabolism 

Committee Meeting (MARC) considered the residues of concern for residues for dietary items 

(e.g., in plants and commodities) (Abbots, 1995a, 1995b). The committee determined that the 

residue to be regulated in plants and animal commodities was parent chlorsulfuron only. It is 

anticipated that the residues of concern for human health drinking water will be revisited as new 

fate data (e.g., aerobic and anaerobic metabolism data and an aquatic field dissipation study) that 

could influence the decision on the potential residues of concern for human health drinking water 

become available. 

Residues of Concern for Ecological Risk Assessment

The residues of concern for exposure to aquatic organisms are assumed to be chlorsulfuron, odesmethyl chlorsulfuron, ring-opened chlorsulfuron, and 2-chlorophenylsulfonyl urea. These 

degradates retain the sulfonylurea group and/or have data that suggest that chronic toxicity to 

daphnid will be within an order of magnitude of the parent. These residues are expected to have 

the greatest impact on the risk assessment for aquatic plants as sulfonylureas are highly toxic to 

plants and fate data will influence exposure estimates for aquatic plants. Structural activity 

relationships combined with exposure estimates indicate that degradates that are in a separate 

chemical class are not significantly more toxic than the parent such that they would change the 

risk conclusions from evaluating risk due to exposure to the parent alone. Therefore, they were 

determined to be not of concern. Justifications for the determinations on the ecological residues 

of concern are described in Appendix I. 

Method of Estimating Exposure and Evaluating Risk for Degradates

To estimate exposure to compounds assumed to have toxicity similar to that of the parent (e.g.,

o-desmethyl chlorsulfuron, ring-opened chlorsulfuron, and 2-chlorophenylsulfonyl urea for the 

ecological risk assessment), a total toxic residue (TTR) approach will be used.

8

 This entails

summing the residues observed in fate studies, and then estimating degradation rates based on 

the total summed residues. The resulting TTR degradation rates will then be used to estimate 

exposures, in place of degradation rates based on parent alone. Data on organic-carbon 

normalized distribution coefficients are requested for degradates observed in high percentages in 

 8 Justifications for the determinations on the ecological residues of concern are described in Appendix I. 
28

the fate studies (ring-opened chlorsulfuron and 2-chlorophenylsulfonyl urea)

9

. In the TTR 

approach, the lowest KOC will be used in modeling, under the assumption that this provides the 

most conservative estimate of residue mobility. Modeled total toxic residue concentrations will 

then be compared to the most sensitive toxicity endpoints for the parent or residue of concern. 

Table 8 summarizes the approaches to be used for assessing risks to various taxa from different 

transformation products.

Table 8. Summary of residues of concern for different classes of organisms

Transformation Product

Is the transformation product a residue of concern?

If yes, assessment method.

Aquatic 

Animals

Aquatic 

Plants

Terrestrial 

Vertebrates

Terrestrial 

Invertebrates

Terrestrial 

Plants

O-desmethyl chlorsulfuron Yes-TTR1 Yes-TTR1 Yes-TTR1,2 Yes-TTR1,2 Yes-TTR1,2

Ring-opened chlorsulfuron Yes-TTR1 Yes-TTR1 Yes-TTR1,2 Yes-TTR1,2 Yes-TTR1,2

2-Chlorophenylsulfonylurea Yes-TTR1 Yes-TTR1 Yes-TTR1,2 Yes-TTR1,2 Yes-TTR1,2

Triazine amine No No No No No

Triazine urea No No No No No

Hydroxyl triazine amine No No No No No

Dihydoxy triazine No No No No No

Chlorosulfonamide No No No No No

Hydroxy chlorosulfonamide No3 No3 No3 No3 No3

O-desmthyl triazine amine No3 No3 No3 No3 No3

5-hydroxy chlorsulfuron No3 No3 No3 No3 No3

Acetylbiuret No3 No3 No3 No3 No3

Abbreviation: TTR= Total toxic residue approach

1 Residues included in the TTR approach for these taxa are the parent and o-desmethyl chlorsulfuron, ringopened chlorsulfuron, and 2-chlorosulfonylurea. 

2 As these degradates are assumed to have similar toxicity to the parent and exposure estimates are not 

related to the fate data, the presence of these degradates does not alter the estimate of risk for these taxa 

from that estimated for the parent alone. If one of these degradates is found to be more toxic than the 

parent or if the presence of these degradates could influence the estimate of exposure, this approach will be 

revisited.

3 Determined not to be a residue of concern based on a low likelihood of exposure as this degradate was not 

observed in laboratory or field studies. This may be re-evaluated if this residue is observed in fate studies 

in the future.

For terrestrial organisms, residues of concern are the same as residues of concern identified for

aquatic organisms. While the TTR approach was identified as the method to evaluate risk due to 

exposure to chlorsulfuron and major degradates, fate data are not used in T-REX (unless foliar 

dissipation data are available10) and Terrplant, the models used to estimate terrestrial exposure. 

Therefore, use of the TTR approach for terrestrial animals will not change their exposure 

estimates. If terrestrial exposure estimation methods change in the future so as to incorporate 

environmental fate data, a more complete analysis of exposures to residues of concern for 

terrestrial animals may be possible.

 9 Batch equilibrium data for o-desmethylchlorsulfuron is not requested. While loss of a methyl group is likely to 

influence the measured sorption coefficients, it is assumed that the measured values would be similar to those 

measured for chlorsulfuron. EPIWEB version 4.1 predicted KOC values of 124, 423, and 1 L/kg-organic carbon for 

parent, ring opened chlorsulfuron, and 2-chlorophenylsulfonylurea, respectively. 10 Foliar dissipation data are not available for chlorsulfuron. 
29

Mixtures

Evaluation of pesticide environmental mixtures is beyond the scope of this assessment because 

of myriad factors that cannot be quantified based on the available data. Those factors include 

identification of other possible co-contaminants and their concentrations, differences in the 

pattern and duration of exposure among contaminants, and the differential effects of other 

physical/chemical characteristics of the receiving waters (e.g. organic matter present in sediment 

and suspended water). Evaluation of factors that could influence additivity/synergism is beyond 

the scope of this assessment and the capabilities of the available data to allow for an evaluation. 

However, it is acknowledged that not considering mixtures could over- or under-estimate risks 

depending on the type of interaction and factors discussed above. The assessment will, however, 

analyze the toxicity of formulated products (including formulations involving more than one 

active ingredient) and will determine whether formulated products are more toxic than the 

technical grade active ingredient data used for assessing both direct and indirect risks. Twentytwo products also have one of the following active ingredients: aminocyclopyrachlor, 

flucarbazone-sodium, metsulfuron, sulfentrazone, or sulfameturon (Appendix A). 

Flucarbazone-sodium, metsulfuron, and sulfentrazone are herbicides that like chlorsulfuron act 

on acetolactate synthetase (ALS) (Ware and Whitacre, 2004). Aminocyclopyrachlor is an 

pyrimidine carboxylic acid class herbicide (Ullagadi et al., 2010) and sulfentrazone is an anilide 

herbicide; Aminocyclopyrachlor and sulfentrazone have different modes of action from 

chlorsulfuron (Wood, 2009). If use of any of these products result in spray drift to a water body, 

acute aquatic toxicity data on a representative typical end-use product should be available for 

that mixture of ingredients. Additionally, terrestrial plant toxicity data should be available for a 

typical end-use product containing the combination of active ingredients.

12. Risk Hypothesis

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

assessment endpoint response along with the rationale for their selection. For chlorsulufuron, the 

following ecological risk hypothesis is being employed for this national-level ecological risk 

assessment:

Given the uses of chlorsulfuron and its environmental fate properties, there is a likelihood 

of exposure to non-target terrestrial and/or aquatic organisms. When used in accordance 

with the label, chlorsulfuron and its degradates may result in adverse effects upon the 

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

These nontarget organisms may include Federally-listed threatened and endangered 

species. Based on the previous risk assessment and analysis supporting this problem 

formulation, direct effects are likely for aquatic and terrestrial plants, and indirect effects 

may result for all other taxa due to direct effects on plants. 
30

13. Exposure Pathways of Concern, Models, and Toxicity Endpoints

The environmental fate properties of chlorsulfuron and use patterns indicate that direct spray, 

spray drift, leaching to ground water, and runoff represent important transport pathways. 

Chlorsulfuron may also be introduced into water bodies including streams, rivers, ponds, 

marshes, etc., when rising water (i.e. as a result of flooding) inundates terrestrial areas where the 

chemical has been applied. Potential exposure pathways and justifications for including them or 

not in the risk assessment are discussed below. Table 9 summarizes the exposure pathways, 

toxicity endpoints, and models used in the risk assessment. More information on the exposure 

models is provided in Section 14.1. More information on the endpoints that will be used in the 

assessment is available in Section 7.

Considerations in Defining Exposure Pathways 

Although chlorsulfuron may be applied as a granule or as a flowable liquid, spray drift is only 

expected to result in significant exposure with broadcast applications (both aerial and ground 

spray) of the flowable liquid formulations. Dry formulations that are applied as a flowable liquid 

may result in significant spray drift exposure. Applications with hand-held sprayers are assumed 

to result in minimal spray drift. 

Exposure to Birds and Mammals via Inhalation and Drinking Water

Using currently available aquatic toxicity data for animals, the Screening Tool for Inhalation 

Risk (STIR) version 1.0 (November 23, 2010) indicates that exposure via inhalation is not likely 

to present a risk concern for birds and mammals (Appendix D). These results combined with 

the low rate of volatilization indicate that long-range transport in the vapor phase is not an 

exposure pathway of concern. The Screening Imbibition Program (SIP) version 1.0, August 19, 

2010 indicates that chlorsulfuron has the potential to be present in drinking water at sufficiently 

high concentrations to result in a risk concern (Appendix D).11 This is a highly conservative 

evaluation, as SIP assumes that concentrations in drinking water could be at the level of 

solubility. Additionally, non-definitive acute endpoints for mammals and birds and definitive 

chronic endpoints were used in the model. Given the low toxicity of chlorsulfuron to animals it 

is likely that risk to birds and mammals exposed to residues in drinking water will be at 

acceptable levels.

Bioconcentration, Exposure in Sediment, and Leaching to Groundwater

Chlorsulfuron’s KOA, KOW, and BCF indicate that chlorsulfuron is not likely to bioconcentrate or 

bioaccumulate in aquatic or terrestrial organisms. Freundlich organic-carbon normalized 

distribution coefficients (KFOC) range from 8 to 31 (mg/L)(mg/kg)-1/n, indicating that chlorsulfuron

has the potential to leach into groundwater and that sediment does not need to be considered as a 

separate exposure pathway for aquatic invertebrates. Finally, surface and ground water 

 11 At pH 7 and above it is a potential concern for mammals and birds due to both acute and chronic exposure. At pH 

5, it is a potential concern for birds via acute and chronic exposure and a potential concern for mammals due to 

chronic exposure only.
31

contaminated with chlorsulfuron has the potential to be used as irrigation water, which would

result in exposure to terrestrial plants (Kiernan and Young, 2005, DP330621). 

Table 9. Summary of exposure pathways, endpoints, and models used in risk assessment.

Assessed 

Group

Endpoints Evaluated Transport and 

Exposure Pathway

Method of Estimating Exposure

Aquatic 

Vertebrates

Acute: 96-hr LC50

Chronic: NOAEC

Spray drift and runoff to 

water column

Rise of water after 

application to dry 

surface in 

wetlands/marsh/ etc.

Sediment does not need 

to be considered as a 

separate exposure 

pathway

PRZM/EXAMS, AgDRIFT or 

AgDISP

Method to be determined

Aquatic 

Invertebrates

Acute: 48-hr LC50/EC50

Chronic: NOAEC

Aquatic 

Plants EC50

Terrestrial 

Vertebrates

Acute: Oral LD50/

DietaryLC50

Chronic: NOAEC

Spray Drift and direct 

spray to

Residues on foliage

Residues in drinking 

water

Inhalation not a pathway 

of concern

Bioconcentration in 

aquatic organisms not a 

pathway of concern

AgDRIFT or AgDISP

TREX, AgDRIFT or AgDISP

Method to be determined

Terrestrial 

Invertebrates Method under development

Terrestrial 

Plants

EC25, EC05, and 

NOAEC

Runoff (vegetative vigor 

and seedling emergence) 

and Spray Drift

(vegetative vigor)

Water used as irrigation 

water

TERRPLANT and AgDRIFT or 

AgDISP

SCIGROW and PRZM/EXAMs

Human 

Health 

Drinking 

Water

See Human Health 

Toxicity Assessment

Surface Water

Ground Water

PRZM/EXAMs

SCIGROW

14. Analysis Plan 

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

estimated. The registered uses, environmental fate, and ecological effects of chlorsulfuron are 

characterized and integrated to assess the risks. This is accomplished using a risk quotient (ratio 

of exposure concentration to effects concentration) approach. Although risk is often defined as 
32

the likelihood and magnitude of adverse ecological effects, the risk quotient-based approach does 

not provide a quantitative estimate of likelihood and/or magnitude of an adverse effect. 

However, as outlined in the Overview Document (USEPA, 2004), the likelihood of effects to 

individual organisms from particular uses of chlorsulfuron is estimated using the probit doseresponse slope and either the level of concern (discussed below) or actual calculated risk quotient 

value.

This analysis plan will be revisited, and may be revised depending upon information submitted 

by stakeholders and the public in response to the opening of the Registration Review docket for 

chlorsulfuron.

14.1. Measures of Exposure 

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

terrestrial organisms as described at http://www.epa.gov/pesticides/science/models_db.htm. 

The versions used by the Agency at the time the risk assessment is completed will be used in the 

assessment.

14.1.A. Exposure in the Aquatic Environment

Exposure to organisms in surface water will be estimated using PRZM/EXAMs.

According to the EFED Table 1 LUIS report (dated 08/03/2012), chlorsulfuron may be used in 

airports and landing fields, commercial and industrial lawns, commercial storages and 

warehouses, outdoor industrial construction areas, nonagricultural rights-ofways/fencerows/hedgerows, nonagricultural uncultivated areas, ornamental lawns/turf, paved 

areas. EFED is currently exploring methods to assess urban and residential uses of pesticides on 

a national basis. At the present time, EFED considers the use of the impervious surface scenario 

(a PRZM modeling scenario) as the most suitable available modeling approach for impervious 

runoff. The PRZM impervious scenario may be used in tier II PRZM/EXAMS along with a 

residential or other suitable scenario such as rights-of-way (ROW) to obtain EECs. The 

conceptual model for the residential scenario integrates simultaneous modeling of the individual 

use scenario with an impervious scenario. This approach assumes that no watershed is 

completely covered by either 1⁄4-acre lots (the basis for the residential scenario) or undeveloped 

land (the basis for the ROW scenario) for residential and ROW use patterns; therefore, 

differential amounts of runoff will occur within the watershed. The impervious scenario was 

developed to represent the paved areas within a watershed not including roads, parking lots, 

sidewalks, and buildings outside the 1⁄4-acre lot (the 1⁄4-acre lot scenario accounts for impervious 

surfaces such as buildings within the represented area). By modeling a separate scenario for 

impervious surfaces, it is also possible to estimate that amount of exposure that could occur 

when the pesticide is oversprayed onto this surface. Using two scenarios in tandem requires 

post-processing of the modeled output in order to derive a weighted EEC that represents the 

contribution of both the pervious (i.e., residential and ROW scenarios) and the impervious 

surfaces. Exposure from both scenarios can also be weighted and aggregated. The daily time 

series from each model run from the time series file (NAME_TS.out) generated from the PRZM 

graphical user interface (PE5.pl) residential and impervious surface scenarios are combined 
33

using Microsoft® EXCEL. The time series data are weighted based on percentage of impervious 

surface and pervious surface, the percentage of the pervious and impervious surface treated, and 

an adjusted time series is created. Rolling averages for the relevant durations of exposure (e.g., 

21-day and 60-day averages) are calculated, and the relevant one-in-ten year return EEC is 

generated from these distributions.

Concentrations of chlorsulfuron and associated residues (o-desmethylchlorsulfuron, ring-opened 

chlorsulfuron, and 2-chlorosulfonylurea for ecological risk assessment, and parent chlorsulfuron 

for human health drinking water) in ground water will be estimated using EFED's Tier I aquatic 

model SCIGROW (Screening Concentration In Ground Water)(USEPA, 2011). 

In addition to modeling estimates, available monitoring data will be evaluated. Monitoring data 

will include those collected/reported by states as well as other federal departments/agencies (e.g., 

USGS National Water Quality Assessment; http://water.usgs.gov/nawqa/). 

A downstream dilution model (under development) may be used to identify areas downstream 

from use areas that may have EECs high enough to result in risk concerns. This analysis will be 

used to define potential areas of effects for listed species. 

14.1.B. Exposure to Terrestrial Animals 

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

area exposed to spray drift will be derived using the T-REX model (version 1.4.1, 10/09/2008) 

(USEPA, 2008). This model incorporates the Kenaga nomograph, as modified by Fletcher et 

al.(J. S. Fletcher et al., 1994) (1994), which is based on a large set of field residue data. The 

upper-limit values from the nomograph represent the upper bound 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 (J. S. 

Fletcher et al., 1994). T-REX generates exposure estimates based on these data, and assuming a 

35-day foliar dissipation half-life in the absence of Foliar Residue Dissipation data.

For applications of granules containing chlorsulfuron, acute exposure and risks to terrestrial 

wildlife are estimated with the conceptual approach and the LD50/ft2 method employed in the 

model T-REX. Terrestrial EECs will be calculated based on an estimation of loadings of 

pesticide per unit area (expressed in terms of mg a.i./ft2

) for a single application (multiple 

applications are not accounted for in this analysis); the available mass of pesticide per square 

foot is then compared to the acute oral dose for toxicity (LD50 values adjusted for body weight 

and percent body weight consumed) to derive risk quotients for birds and/or mammals. Acute 

and chronic exposures for granules are also estimated based on the direct consumption of 

granules. 

14.1.C. Exposure to Terrestrial Plants

EECs for terrestrial plants inhabiting dry and wetland areas are derived using the program 

TERRPLANT (version 1.2.2, 12/26/2006) (USEPA, 2006). This model uses estimates of 
34

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

application rate and minimum incorporation depth. AgDRIFT may also be used to assess 

exposure to spray drift.

Non-target crops may be exposed to contaminated irrigation waters from surface water or 

shallow ground water containing chlorsulfuron. The potential risks to plants when exposed to 

irrigation water contaminated with chlorsulfuron will be estimated for both ground water and 

surface water irrigation sources. The EEC for ground water will be calculated using the Tier 1 

SCIGROW model, while that for surface water will be calculated using PRZM and EXAMS

results from the scenario yielding the highest EECs. Comparisons will be made to the most 

sensitive endpoint from the vegetative vigor study, under the assumption that irrigation water 

does not run off or infiltrate, but stays ponded at the surface.

14.1.D. Exposure to Spray Drift 

Two spray drift models, AgDISP and AgDRIFT, are used to assess exposures of aquatic and 

terrestrial organisms to chlorsulfuron deposited in terrestrial and aquatic habitats by spray drift. 

AgDrift (Spray Drift Task Force Spray Software) is the model most commonly used by EFED to 

simulate spray drift into terrestrial and aquatic environments. AgDISP (Teske and Curbishley, 

2003) is used when a parameter needs to be modeled that is not available in AgDRIFT. Spray 

drift analysis will be an important part of the analysis in defining the potential area of effects for 

endangered species.

14.2. Measures of Effect

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

Data are obtained from registrant-submitted studies or from literature studies identified by 

ECOTOX. The ECOTOXicology database (ECOTOX) will be searched in order to provide 

more ecological effects data 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 Mid-Continent Ecology Division (USEPA, 2009a).

Information on the potential effects of chlorsulfuron on non-target animals is also collected from 

the Incident Data System (IDS), the Ecological Incident Information System (EIIS, version 

2.1.1) (USEPA, 2012b). The EIIS is a database containing adverse effect (typically mortality) 

reports on non-target organisms where such effects have been associated with the use of 

pesticides. Both IDS and EIIS are maintained by the Agency’s Office of Pesticide Programs. 

Another data base with information on non-target birds is the Avian Monitoring Information 

System (AIMS), which is maintained by the American Bird Conservancy. See Section 7.4 above 

for details about reported incidents involving chlorsulfuron.

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

studies will be evaluated qualitatively. Such effects have included behavioral changes (e.g., 

lethargy, changes in coloration and effects olfaction). Quantitative assessments of risks, though, 
35

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 employs the assumption that 

toxicity of chlorsulfuron to birds is similar to that for terrestrial-phase amphibians and reptiles. 

An analogous assumption is made for fish and aquatic-phase amphibians. 

The acute measures of effect used for animals in this screening-level 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. 

14.3. Integration of Exposure and Effects

Risk characterization is the integration of exposure and ecological effects characterization to 

determine potential ecological risks from the use of chlorsulfuron as described on labels, and the 

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

The exposure and toxicity effects data are integrated in order to evaluate the risks of adverse 

ecological effects on non-target species. For the assessment of chlorsulfuron risks, the risk 

quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are 

divided by acute and chronic toxicity endpoints. The resulting RQs are then compared to the 

Agency’s LOCs (USEPA, 2004). These criteria are used to indicate when uses of chlorsulfuron, 

as directed on the label, have the potential to cause adverse direct or indirect effects to non-target 

organisms. As noted previously, where data are lacking on the toxicity of chlorsulfuron or its 

transformation products, risk will be presumed. 

 

14.3.A. Deterministic and Probabilistic Assessment Methods

Calculation of risk quotients (and the determinations of areas of effect which are calculated using 

risk quotients) will primarily depend on the deterministic point-estimate based approach. An 

effort may be made to further describe risk using probabilistic tools that the Agency has 

developed. These tools have been reviewed by FIFRA Scientific Advisory Panels and have been 

deemed as appropriate means of refining assessments where deterministic approaches have 

identified risks.
36

14.4. Endangered Species Assessments

Consistent with the Agency’s responsibility under the Endangered Species Act (ESA), the 

Agency will evaluate risks to Federally-listed threatened and/or endangered (listed) species from 

registered uses of chlorsulfuron. 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 action area is used to identify all listed (threatened and endangered) species and designated 

critical habitat that could be affected by the Federal action. The Federal action is the 

authorization or registration of pesticide use or uses as described on the label(s) of pesticide 

products containing a particular active ingredient. The action area is defined by the Endangered 

Species Act as, “all areas to be affected directly or indirectly by the Federal action and not 

merely the immediate are involved in the action” (50 CFR §402.2). Based on an analysis of the 

Federal action, the action area is defined by the actual and potential use of the pesticide.

In the case of nationwide ecological risk assessment conducted for chlorsulfuron under 

Registration Review, the action area will encompass the entire United States and its territories. 

The purpose of defining the action area as the entire United States and its territories is to ensure 

that the initial area of consideration encompasses all areas where chlorsulfuron may be used now 

and in the future, including the potential for off-site transport via spray drift and downstream 

dilution. Additionally, the concept of a nationwide action area takes into account the potential 

for direct and indirect effects and any potential modification to critical habitat based on 

ecological effect measures associated with reduction in survival, growth, and reproduction, as 

well as the full suite of sublethal effects available in the effects literature. It is important to note 

that the nationwide action area does not imply that direct and/or indirect effects and critical 

habitat modification are expected to, or are likely to occur over the full extent of the action area, 

but rather to identify all listed species and critical habitat that may potentially be affected by the 

action. The Agency will use more rigorous analysis including consideration of available land 

cover data, toxicity data, and exposure information to determine areas where individual listed 

species and designated critical habitat may be affected or modified via endpoints associated with 

reduced survival, growth, or reproduction.

14.5. Human Health Drinking Water Assessment

In order to bring the drinking water assessment up to date with current data, models and 

simulation model guidance, a new drinking water assessment will be conducted to support future 

human health dietary risk assessments of chlorsulfuron. Concentrations of chlorsulfuron (and 

identified residues of concern) in surface waters will be estimated using PRZM and EXAMs (see 

description above). Percent Cropped Area (PCA) adjustment factors are used to account for the 

maximum fractional area within a watershed that may be planted with a modeled crop, and are 

used to modify human health estimated drinking water concentrations predicted by PRZM and 

EXAMS (Echeverria et al., 2012). Chlorsulfuron has uses in agricultural, commercial, and 

residential uses sites; therefore, a PCA of 1.0 will be used. Previous drinking water assessments 

used a PCA of 0.87 for turf uses (Kiernan and Young, 2005, DP330621).
37

An Estimated Drinking Water Concentration (EDWC) of chlorsulfuron in groundwater will be 

estimated using EFED’s Tier I aquatic model SCIGROW version 2.3; 8/8/2003. 

The drinking water assessment will also include available surface and ground water monitoring 

data with consideration of changes in use patterns that may have occurred. States are encouraged 

to submit monitoring data for review.

14.6. Endocrine Disruptor Screening Program

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

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

chronic toxicity, including assessments of carcinogenicity, neurotoxicity, developmental, 

reproductive, and general or systemic toxicity. These studies include endpoints which may be 

susceptible to endocrine influence, including effects on endocrine target organ histopathology, 

organ weights, estrus cyclicity, sexual maturation, fertility, pregnancy rates, reproductive loss, 

and sex ratios in offspring. For ecological hazard assessments, EPA evaluates acute tests and 

chronic studies that assess growth, developmental and reproductive effects in different 

taxonomic groups. As part of its reregistration decision, EPA reviewed these data and selected 

the most sensitive endpoints for relevant risk assessment scenarios from the existing hazard 

database. However, as required by FFDCA section 408(p), chlorsulfuron is subject to the 

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

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

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

produced by a “naturally occurring estrogen, or other such endocrine effects as the Administrator 

may designate.” The EDSP employs a two-tiered approach to making the statutorily required 

determinations. Tier 1 consists of a battery of 11 screening assays to identify the potential of a 

chemical substance to interact with the estrogen, androgen, or thyroid (E, A, or T) hormonal 

systems. Chemicals that go through Tier 1 screening and are found to have the potential to 

interact with E, A, or T hormonal systems will proceed to the next stage of the EDSP where EPA 

will determine which, if any, of the Tier 2 tests are necessary based on the available data. Tier 2 

testing is designed to identify any adverse endocrine-related effects caused by the substance, and 

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

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

October 2009 and February 2010, EPA issued test orders/data call-ins for the first group of 67 

chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. Chlorsulfuron

is not among the group of 58 pesticide active ingredients on the initial list to be screened under 

the EDSP (http://www.epa.gov/scipoly/oscpendo/pubs/final_list_frn_041509.pdf). Accordingly, 

as part of registration review, EPA will issue future EDSP orders/data call-ins, requiring the 

submission of EDSP screening assays for chlorsulfuron. For further information on the status of 

the EDSP, the policies and procedures, the list of 67 chemicals, future lists, the test guidelines 

and the Tier 1 screening battery, please visit our website: http://www.epa.gov/endo/.
38

15. Preliminary Identification of Data Gaps 

15.1. Fate

Several fate studies are needed to better characterize the environmental fate and transport of 

chlorsulfuron. Given that the primary risk concern for chlorsulfuron is risk to plants; the main 

uncertainties these data requirements will help understand is the potential risk to plants. The 

studies listed below will decrease the uncertainty in determining the potential exposure to the 

pesticide. 

• Aerobic Soil Metabolism (OPPTS12,13 Guideline number 835.4100) for parent

• Aerobic Aquatic Metabolism (OPPTS Guideline Number 835.4300) for parent

• Anaerobic Aquatic Metabolism (OPPTS Guideline Number 835.4400) for parent

• Aquatic Field Dissipation Study (OPPTS Guideline Number 835.6200) for parent

• Environmental Chemistry Methods for Soil and Plant Material (OCSPP Guideline 

850.6100) for parent and major degradates 

• Environmental Chemistry Methods for Water (OCSPP Guideline 850.6100) for parent 

and major degradates to support the aquatic field dissipation study

Table 10 summarizes the fate data requirements for chlorsulfuron. A rationale discussing the 

need for each study is also provided below.

Table 10. Summary of Submitted Environmental Fate Studies, Study Classifications and 

Data Gaps for Chlorsulfuron and Its Degradates

OPPTS or 

OCSPP 

Guideline

MRID

(Test 

Substance1)

Study 

Classification

Comments on Study 

Classification Data Gap?3 Comments

Hydrolysis

835.2120

(161-1)

35270 Not formally 

classified

Guideline study 

recommended in 

Garner (1980).

83946 Invalid No --

Raw data not 

provided. 

Radiochemical purity 

not provided. 

Percentages of 

degradates not 

provided.

42156701

same as

41408102

Acceptable

Aqueous 

Photolysis 

835.2240

(161-2)

42156702

Same as

41408101

Acceptable No --

 12 Office of Prevention, Pesticides, and Toxic Substances (OPPTS) is now the Office of Chemical Safety and 

Pollution Prevention (OCSPP); however, some guidelines still reference OPPTS and so those guidelines are 

referenced with OPPTS in this document. 13 A list of all OPPTS and OCSPP Guidelines discussed in this document is available in Appendix G.

.
39

OPPTS or 

OCSPP 

Guideline

MRID

(Test 

Substance1)

Study 

Classification

Comments on Study 

Classification Data Gap?3 Comments

Soil Photolysis

835.2410

(161-3)

83947 same as 

86813 Invalid --

41721001 No --

same as

42156703

Acceptable --

Aerobic Soil 

Metabolism 

835.4100

(162-1)

42214201

Most studies 

unacceptable, 

one study 

supplemental

Not enough 

information is 

available in the studies 

to use the results to 

fulfill guideline 

requirements

Yes

Metabolism data are needed to 

estimate exposure to residues 

in the aquatic environment 

and to define the 

transformation products likely 

to occur in aerobic soil. 

00035273 Supplemental

Maintained in a 

greenhouse and 

temperature was not 

held constant.

00035275 same 

as

00086814 and

00083950

Supplemental

One ring labeled. 

One replicate. No raw 

data. Degradates not 

followed.

Anaerobic Soil 

Metabolism

835.4200

(162-2)

No data 

submitted Not applicable -- No

While anaerobic soil 

metabolism data are required 

according the 40 CFR 

158.1300, these data are not 

used in exposure modeling 

and exposure of chlorsulfuron 

to humans in ground water is 

currently not a major concern. 

Therefore, these data would 

likely have little impact on the 

risk conclusions.

Aerobic Aquatic 

Metabolism 

835.4300

(162-4)

No data 

submitted Not applicable -- Yes Metabolism data are needed to 

estimate exposure to residues 

in the aquatic environment 

and to define the 

transformation products likely 

to occur in the aquatic 

environment. 

Anaerobic 

Aquatic 

Metabolism 

835.4400

(162-3)

42156701

same as

00086815

Supplemental

Alfalfa added to test 

system. Degradation 

was faster in sterile 

controls suggesting 

that degradation was 

not mediated by 

microbes.

Yes

Batch 

Equilibrium

835.1230

(163-1)

42156705 Supplemental Adequate data for 

parent on 4 soils

No

Batch equilibrium data are 

available on 4 soils only. 

Typically data are also 

available on a sediment as 

well. Data were not requested 

as they are not expected to 

substantially impact the risk 

conclusions. 

00083948 Invalid

45371826 Invalid

46155803

Triazine amine Under review
40

OPPTS or 

OCSPP 

Guideline

MRID

(Test 

Substance1)

Study 

Classification

Comments on Study 

Classification Data Gap?3 Comments

Aquatic Field 

Dissipation

835.6200

No data 

available NA -- Yes

As chlorsulfuron may be used 

in areas that will become 

flooded after use, an aquatic 

field dissipation study is 

recommended that is 

representative of these use 

patterns. 

Terrestrial Field 

Dissipation

No data 

available NA -- No

Lysimeter studies are 

available and additional data 

are not expected to impact 

risk conclusions.

Bioconcentration 

Factor

850.1730

42214204

00083951

00086820

Supplemental

MRID 42214204 is a 

compilation of 

00083951 and 

00086820.

No

KOW range from 0.04 to 2.16 

and chlorsulfuron is not likely 

to bioconcentrate.

Environmental 

Chemistry 

Method: Water

850.6100

43406701 

supplemented 

by 43406702

Not reviewed

Solid phase extraction 

with C18 cartridge 

and HPLC-UV: 

chlorsulfuron, 

metsulfuron methyl, 

and several other 

compounds. No 

independent 

laboratory validation. 

Limit of detection was 

0.05 μg/L.

Yes

An ECM and ILV are needed 

with a limit of quantitation 

(LOQ) for the parent below 

0.2 μg/L that may be used in 

monitoring.

2 All major 

degradates should be included 

in the method and have an 

associated LOQ and limit of 

detection (LOD) lower than 

levels that would result in a 

risk concern.

Environmental 

Chemistry 

Method: Soil

and sediment

850.6100

No data 

available NA -- Yes

An ECM and ILV are needed 

with associated LOQ and 

LOD for all major degradates 

for soil and sediment. The 

method(s) is needed to 

support the terrestrial field 

dissipation study and to 

provide the ability to monitor 

for chlorsulfuron in the case. 

Environmental 

Chemistry 

Method: Plant 

Material

850.6100

No data 

available NA -- Yes

An ECM and ILV are needed 

with associated LOQ and 

LOD for all major degradates 

for soil and sediment. The 

method(s) is needed to 

support the terrestrial field 

dissipation study and to 

monitor for chlorsulfuron. 

Abbreviations: ECM=Environmental Chemistry Method; ILV=independent laboratory Validation

1 Test substance is included if the study was conducted on a material other than the parent, chlorsulfuron.

2 The LOQ was based on the NOAEC for aquatic vascular plants (NOAEC = 0.00024 mg a.i./L) and an LOC of 1

(MRID 45832901).

3 The study is considered a data gap if it is required in 40 CFR 158.1300 or data are needed to reduce uncertainty 

in the risk assessment.
41

15.1.A. Rationales for Requesting Fate Studies

• Aerobic Soil Metabolism (OPPTS Guideline number 835.4100) for parent; 

Aerobic Aquatic Metabolism (OPPTS Guideline Number 835.4300) for parent; 

Anaerobic Aquatic Metabolism (OPPTS Guideline Number 835.4400) for parent; 

These three data requirements are standard data requirements for terrestrial and aquatic use

patterns and available data are not adequate for risk assessment (40 CFR Part 158.1300). Data 

are needed to 1) identify potential degradates and transformation products, 2) better understand 

the potential for metabolism and degradation in the environment, and 3) to determine how the 

environmental fate of chlorsulfuron in the field compares to that predicted by laboratory studies. 

In the absence of laboratory studies examining degradation kinetics, degradation of chlorsulfuron 

in various media will either be assumed to be stable or a conservative estimate of degradation 

will be estimated based on open literature data. 

• Aquatic Field Dissipation Study (OPPTS Guideline Number 835.6200) for representative 

end-use products and uses; 

Environmental Chemistry Methods for Water (OCSPP Guideline 850.6100) for parent 

and major degradates to support the aquatic field dissipation study

Chlorsulfuron may be applied to intermittently dry areas including wetlands, marshes, and bogs. 

It is possible that chlorsulfuron will be introduced into the aquatic environment when water rises 

after areas are treated with chlorsulfuron. This is similar to an aquatic use. Aquatic field 

dissipation studies are standard data requirements for applications to water bodies and the use 

pattern is similar to uses on rice where a pesticide is applied to a dry field and the field is then 

flooded. The aquatic field dissipation study is requested in order to better understand the 

potential for aquatic exposure and exposure to degradates from uses in intermittently dry areas. 

This study is most important in informing the exposure assessment for aquatic plants from these 

use patterns. Aquatic field dissipation studies require the submission of an environmental 

chemistry method and corresponding independent laboratory validation (ILV) specific to the 

parent and major transformation products observed in environmental laboratory studies. It is 

recommended that a protocol be submitted prior to initiation of the study.

• Environmental Chemistry Methods for Water (OCSPP Guideline 850.6100) for parent 

and major transformation products;

Environmental Chemistry Methods for Soil (OCSPP Guideline 850.6100) for parent and 

major transformation products;

Environmental Chemistry Methods for Plants (OCSPP Guideline 850.6100) for parent 

and major transformation products

Environmental Chemistry Methods (ECM) and ILV in water, soil, and plants are needed with a 

limit of quantitation (LOQ) that are relevant to the potential for risk for plants. LOQ for 

residues of concern should be low enough to cover the concentration that could result in a risk 

concern (e.g., toxicity endpoint multiplied by the LOC). For water, the LOQ should be below

0.2 μg/L. Methods and associated ILV are also needed to support field dissipation studies and 

the method evaluated must be the same method used in the corresponding field dissipation study. 
42

One method may be used to fulfill both data needs. All major degradates should be included in 

the method and have an associated LOQ and limit of detection (LOD). Currently available 

methods do not have an ILV or low enough LOQ and LOD.

15.1.B Rationales for Not Requesting Fate Studies

• Anaerobic Soil Metabolism (OPPTS Guideline Number 835.4200) for parent

While anaerobic soil metabolism data are required according the 40 CFR 158.1300, these data 

are not used in exposure modeling and exposure of chlorsulfuron to humans in ground water is 

currently not a major concern. Therefore, these data would likely have little impact on the risk 

conclusions. Therefore, this study is not requested at this time.

• Batch Equilibrium (OPPTS Guideline Number 835.1230) for parent in one sediment

Sorption coefficients were measured on four soils. Data are normally measured on four soils and 

one sediment. Sediment sorption coefficients are often higher than those measured in soil; 

Allen-king et al. (Allen-King et al., 2002) state that, “compared to soil organic matter, freshwater 

sediment organic matter has been reported to contain fewer polar functional groups, and has been 

observed to have roughly 2-fold greater HOC [hydrophobic organic sorption]. Based on 

chlorsulfuron’s water solubilities and pKa value, its affinity to organic materials (and thus

organic carbon partition coefficient, KOC) is expected to decrease with increasing pH. Submitted 

batch equilibrium data do not confirm this; however, open literature support the conclusion that 

pH is one of the most important factors in the resulting sorption coefficients and is more 

important than the percent organic carbon (Cotterill et al., 1989). Additional data on sorption in 

sediment is not expected to alter the risk conclusions because of the following:

1) pH is one of the main factors influencing sorption of chlorsulfuron. Sorption coefficients 

for soil are available over a range of pH (5.4 to 8). 

2) Sorpiton coefficients in soil indicate that chlorsulfuron has a high mobility 

• Batch Equilibrium (OPPTS Guideline Number 835.1230) for ring-opened chlorsulfuron 

and 2-chlorophenylsulfonylurea

The ecological risk assessments identified ring-opened chlorsulfuron and 2-

chlorophenylsulfonylurea as residues of concern for chlorsulfuron. Both of these residues were 

major residues observed in laboratory and field studies. Therefore, data on the sorption 

coefficients of these degradates are needed to permit estimation of concentrations of total toxic 

residues in water. O-desmethyl chlorsulfuron is expected to have mobility similar to that of the 

parent; therefore, data on the parent compound may be used to estimate soil sorption of this 

degradate. EPIWEB version 1.4 predicted KOC values of 124, 423, and 1 L/kg-organic carbon 

for chlorsulfuron, ring opened chlorsulfuron, and 2-chlorophenylsulfonylurea, respectively. 

These differences in sorption coefficients had little impact on the estimated EEC using 

PRZM/EXAMs. In the absence of additional data, sorption coefficients will be estimated using 

the current version of EPIWEB (USEPA, 2009b). Batch equilibrium studies for degradates are 
43

available in the open literature (AERU, 2012). Submission of these open literature data to the 

agency would reduce uncertainty in the final risk assessment.

• Terrestrial Field Dissipation (OPPTS Guideline Number 835.6100) for parent

While a terrestrial field dissipation study is required according to 40 CFR Part 158.1300, these 

data are not used in exposure modeling and lysimeter studies are available that provide 

information on the leaching behavior and degradates observed in the field. Therefore, these data 

would likely have little impact on the risk conclusions. Therefore, this study is not requested at 

this time.

15.1.A. Additional Information that would be Useful for Monitoring and Risk 

Assessment

Having access to sensitive methods (and standards) using a variety of instruments would enable 

State Agencies and other interested third parties to investigate incidents or other impacts 

associated with chlorsulfuron use and could provide Agency with a better set of field data than 

we have at the present to assess the risk to plants as a results of typical use. These methods 

could be specific to chlorsulfuron and/or its transformation products, or multiresidue methods for 

multiple compounds that include chlorsulfuron and/or its degradates. These methods would add 

to the methods already available for monitoring. 

 

15.2. Effects

The ecological effects database for chlorsulfuron parent is complete and adequate for risk 

assessment. Additional ecological effects studies on chlorsulfuron are not needed at this time to 

assess the potential risk of chlorsulfuron exposure to non-target organisms. However, if 

application rates change or new uses are proposed in the future, then these data may be required.

Effects studies needed for the degradates or chlorsulfuron are discussed in Section B.3.

The following study is a standard data requirement for chlorsulfuron; however, data are not 

requested at this time. 

• Avian Acute Oral Toxicity Test with a Passerine Species (850.2100)

Table 11 summarizes the effects data requirements for chlorsulfuron. 
44

Table 11. Summary of Submitted Ecological Effects Studies and Data Gaps for Parent 

Chlorsulfuron

OPPTS Guideline MRID Study 

Classification Data Gap? Comments for Data Gap

Terrestrial Animals

850.2100

Avian Oral 

Toxicity –

Waterfowl or 

Upland Game Bird

000352-63 Acceptable No

850.2100

Avian Acute Toxicity 

- Passerine

NA NA No

See discussion below regarding acute toxicity for 

passerines.

850.2200

Avian Dietary 

Toxicity

000352-66 Acceptable No

850.2300

Avian Reproduction 426340-01 Acceptable

Acceptable

No

850.3020

Honeybee Acute 

Contact Toxicity

421299-02 Acceptable No

Aquatic Animals 

850.1075

Freshwater Fish-Acute 

Toxicity

000352-58 Acceptable No

850.1075

Saltwater Fish-Acute 

Toxicity

419764-01 Acceptable No

850.1010

Freshwater 

Invertebrates-Acute 

Toxicity

000352-62 Acceptable No

850.1025

850.1035

Saltwater 

Invertebrates-Acute 

Toxicity

419764-02 Acceptable No

850.1300

Freshwater 

Invertebrates-Life 

Cycle Test

419764-04 Supplemental No

The submitted study has a number of deficiencies 

and deviations from the guideline. However, the 

results of the study are adequate for risk 

assessment.

850.1350

Saltwater 

Invertebrates-Life 

Cycle Test

No data No

850.1400

Freshwater Fish-Early 

Life Stage Test

419764-05 Acceptable No

850.1500

Fish-Life Cycle Test NR No
45

OPPTS Guideline MRID Study 

Classification Data Gap? Comments for Data Gap

Plants 

850.4100

Terrestrial Plant 

Toxicity-Tier 1 

Seedling Emergence

463618-01 Supplemental No

The submitted study does not meet the guideline 

requirements for a seedling emergence study due 

to plant crowding and reduced light conditions. 

However, a new tier 1 seedling emergence study 

is not requested as tier 2 data are available.

850.4225

Terrestrial Plant 

Toxicity-Tier 2 

Seedling Emergence

463618-01 Supplemental No

The submitted study is classified as supplemental 

but data are useful for risk assessment. 

850.4150

Terrestrial Plant 

Toxicity-Tier 1 

Vegetative Vigor

463268-01 Supplemental No

The submitted study does not meet the guideline 

requirements for a vegetative vigor study because 

the application rates tested were lower than the 

maximum application rate, and was not tested on 

all 10 species. However, a new tier 1 vegetative 

vigor study is not requested as tier 2 data are 

available.

850.4150 Terrestrial 

Plant Toxicity-Tier 2 

Vegetative Vigor

463268-01 Supplemental No The submitted study is classified as supplemental 

but data are useful for risk assessment. 

(Non-Guideline)

Special Study-NonTarget Plant 

Reproductive Toxicity

487769-02,

487769-03 Acceptable No

850.4400

Aquatic Plant GrowthAlgae458329-02 Acceptable No

850.4400

Aquatic Plant GrowthVascular Plants

458329-01 Supplemental No

The submitted study was classified as 

supplemental because it was conducted as a static 

test and test concentrations were not measured at 

test termination. However, the study results are 

useful for risk assessment.

Rationales for Not Requesting Acute Oral Toxicity Test with a Passerine Species (850.2100)

According to the 40 CFR Part 158.630, acute oral toxicity data are required for a passerine 

species. Because no acute oral toxicity data have been submitted for a passerine species exposed 

to chlorsulfuron, this is a data gap. No acute oral toxicity data with passerines for chlorsulfuron 

or its degradates have been identified in the scientific literature (using ECOTOX).

Available acute oral toxicity data for birds (MRID 000352-63) indicate that chlorsulfuron is 

practically nontoxic to birds on an acute oral exposure basis. In addition, in a sub-acute dietary 

toxicity study (MRID 000352-66) with the mallard duck, no mortalities were observed at the 

highest test levels (i.e., 5,000 mg a.i./kg-diet) and the compound is classified as practically nontoxic to birds on a subacute dietary exposure basis. In addition, no sublethal effects were 

observed in these studies.
46

Given the low application rate of chlorsulfuron (i.e., 0.12 lb a.i./A for ornamental turf), it is 

expected that the exposure of birds to chlorsulfuron will be low (the dose-based EEC for birds is 

33.31 mg/kg/day based on T-REX version 4.1.1). The lowest acute values for birds are 5,000

mg a.i./kg-bw (highest dose tested) for acute oral toxicity for mallard ducks; the corresponding 

NOAEL value is 5,000 mg a.i./kg-bw (no mortality or frank toxicity was observed). As the acute 

oral toxicity value is based on body weight, the NOAEL value for the avian acute oral was 

entered into T-REX to obtain the adjusted toxicity value for the much smaller passerine bird. 

The adjusted acute toxicity value for 20-g birds is 2596 mg a.i./kg-bw. This estimated acute

toxicity value for birds is at least 79 times the EEC.14 Given the data for acute toxicity of 

chlorsulfuron to aquatic and terrestrial vertebrates and the absence of incident data to the 

contrary, the weight-of-evidence suggests that chlorsulfuron will be relatively nontoxic to 

passerine species as well. Therefore, EFED is not requesting oral toxicity data for passerines 

exposed to chlorsulfuron or its degradates.

15.2.A. Degradate Toxicity Data

Structure-activity relationship data, read across analysis, and exposure estimates were used to 

make the determinations on which degradates would be evaluated in the risk assessment. While 

data on chlorsulfuron degradates are not required, open literature ecotoxicity data are available 

and could be used to confirm the determination (Appendix I). These studies include the 

following for o-desmethyl chlorsulfuron, ring-opened chlorsulfuron, chlorosulfonamide, triazine 

amine, and triazine urea. 

• Freshwater fish-acute toxicity (OPPTS Guideline 850.1075)

• Freshwater invertebrate- acute toxicity (OPPTS Guideline 850.1010)

• 96-hr algal study (OPPTS Guideline 850.4400)

• Freshwater Invertebrates – Life Cycle Test (OPPTS Guideline 850.1300)

Open literature data measuring sorption coefficients for some degradation products are also 

available. Batch equilibrium data on degradates that retain the sulfonylurea bridge would reduce 

uncertainty in the estimated exposure to total residues of concern for ecological risk assessment.

16. Other Information Needs

There is specific information that will assist the Agency in refining the ecological risk 

assessment, including any species-specific effects determinations. The Agency is very interested 

in obtaining the following information:

1. confirmation on the following label information

a. frequency of application, application intervals, formulation types, and maximum 

number of applications per season

b. geographic limitations on use

c. spray drift advisory statements

2. use or potential use distribution (e.g., acreage and geographical distribution of relevant 

crops)

 14 For the lowest ratio for acute terrestrial animals (acute avian oral): 2596 ÷ 33 = 79
47

3. use history

4. median and 90th percentile reported use rates (lbs. a.i./acre) from usage data – national, 

state, and county

5. application timing (date of first application and application intervals) by crop – national, 

state, and county

6. sub-county crop location data

7. directly acquired county-level usage data (not derived from state level data)

a. maximum reported use rate (lbs. a.i./acre) from usage data – county

b. percent crop treated – county

c. median and 90th percentile number of applications – county

d. total pounds per year – county

e. the year the pesticide was last used in the county/sub-county area

f. the years in which the pesticide was applied in the county/sub-county area

8. state or local use restrictions

9. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency

10. monitoring data 

In order to assess the risk to terrestrial organisms exposed to granules the weight of one granule 

for each granule formulation would be useful. 

17. References

 

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Assessment Process for Pesticides with Persistent, Bioaccumulative, and Toxic 

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2009).

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Data Submitted To Support Registration

17.1. Studies Related to Environmental Fate Data

MRID Citation Reference

Reports of Multiple phys/chem Characteristics

31432

E.I. du Pont de Nemours & Company (1977) DPX-4189: Technical Data Sheet. (Unpublished 

study received Jun 16, 1980 under 352-EX- 105; CDL:099459-E)

35255

E.I. du Pont de Nemours & Company (1980) ?Chemical Study of DPX- 4189|. (Unpublished 

study received Jun 16, 1980 under 352-105; CDL:099462-A)

35271 Rapisarda, C.; Shrivastava, S.P.; Butler, L.D. (1978?) Physical Properties of DPX-4189: 

Octanol/Water Partition Ratio, Solubili- ties, and Soil Absorption Data. (Unpublished study 

received Jun 16, 1980 under 352-105; submitted by E.I. du Pont de Nemours & Co., 

Wilmington, Del.; CDL:099462-R)

83941

E.I. du Pont de Nemours & Company (1981) Du Pont Glean^(TM)I Weed Killer: Technical Data 

Sheet. (Unpublished study received Sep 1, 1981 under 352-403; CDL:245878-A)

83948

Rapisarda, C.; Shrivastava, S.P.; Butler, L.D. (1980?) Physical Properties of DPX-4189: 

Octanol/Water Partition Ratio, Solubilities, and Soil Adsorption Data [K-values and TLC (Rf) 
51

Values]: Document No. AMR-28-81. (Unpublished study received Sep 1, 1981 under 352-403; 

submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:245878-I)

99125 E.I. du Pont de Nemours & Company, Incorporated (1981) Du Pont Glean^(TM)I Weed Killer: 

Technical Data Sheet. (Unpublished study received Nov 13, 1981 under 352-404; CDL:070470-

A)

148288

E. I. du Pont de Nemours & Co. (1985) [Product Chemistry Data for Finesse Herbicide]. 

Unpublished compilation. 9 p.

40622707 Armstrong, J. (1988) Physical/Chemical Characteristics of End Use Product Du Pont Avatar 

Herbicide: Laboratory Project ID: FPC-88- 5-PC. Unpublished study prepared by E. I. du Pont 

de Nemours and Co., Inc. 9 p.

42454102 Schmuckler, M.; Moore, L. (1992) Physical and Chemical Characteristics of Chlorsulfuron: Lab 

Project Number: AMR 2370-92. Unpublished study prepared by E. I. du Pont de Nemours and 

Co. 25 p.

42454103

Moore, L. (1992) Solubility of Chlorsulfuron in Organic Solvents Using Continuous Sample 

Agitation: Lab Project Number: AMR 2375-92. Unpublished study prepared by E.I. du Pont de 

Nemours and Co. 16 p.

42454104 Schmuckler, M. (1992) Determination of the Water Solubility of Chlorsulfuron, W4189 

(Revision): Lab Project Number: W4189.B. Unpublished study prepared by E.I. du Pont de 

Nemours and Co. 27 p.

42454105 Schmuckler, M. (1992) Vapor Pressure of Chlorsulfuron at 25 degrees celsius (Revised): Lab 

Project Number: G/PC-22-CA. Unpublished study prepared by E.I. du Pont de Nemours and Co. 

15 p.

43898601

Schmuckler, M. (1992) Vapor Pressure of Chlorsulfuron at 25 (degrees) C: Lab Project Number: 

G/PC-22-CA. Unpublished study prepared by Du Pont Agricultural Products. 15 p.

42454106 Schmuckler, M.; Moore, L.; Wilds, J. (1992) Dissociation Constant of Chlorsulfuron: Lab 

Project Number: AMR 2367-92. Unpublished study prepared by E. I. du Pont de Nemours and 

Co. 22 p.

42454107

Schmuckler, M. (1992) N-Octanol/Water Partition Coefficient of Chlorsulfuron (Revised): Lab 

Project Number: DUP-31-88: AMR-1224-88. Unpublished study prepared by Enviro-Bio-Tech, 

Ltd. and E.I. Du Pont de Nemours. 27 p.

47179901 Huntley, K. (2001) Chlorsulfuron Technical (DPX-W4189): Determination of the UV/Visible 

Absorption. Project Number: 46649, 6283. Unpublished study prepared by Analytical BioChemistry Labs., Inc. 29 p.

47831303

Miller, R. (2009) Chlorsulfuron Technical: Product Properties: Color, Physical State, Odor, 

Stability to Normal and Elevated Temperatures, Oxidation/Reduction: Chemical Incompatibility, 

pH, UV/Visible Absorption, Melting Point/Melting Range, Density/Relative Density/Bulk 

Density, Dissociation Constants in Water, Partition Coefficient (n-Octanol/Water), Water 

Solubility, and Vapor Pressure. Project Number: CHB/EX/640/010/P/1, CHB/OP/MTH/183/P/2, 

CHB/EX/640/001/P/1. Unpublished study prepared by PhibroWood, LLC. 49 p.

42454108

Moore, L. (1992) Stability of Chlosulfuron in the Presence of Metal and Metal Ions, in Sunlight 

and at Normal and Elevated Temperatures: Lab Project Number: AMR 2372-92. Unpublished 

study prepared by E. I. Du Pont de Nemours and Co. 24 p.

Hydrolysis

35270

Han, J.C.Y. (1960?) Hydrolysis and Photolysis Studies with 14C- DPX-4189: AMR-08-80A. 

(Unpublished study received Jun 16, 1980 under 352-105; submitted by E.I. du Pont de Nemours 

& Co., Wil- mington, Del.; CDL:099462-Q)
52

83946

Han, J.C.Y. (19??) Hydrolysis of ^14IC-Labeled DPX-W4189: Document No. AMR-39-81. 

(Unpublished study received Sep 1, 1981 under 352-403; submitted by E.I. du Pont de Nemours 

& Co., Wilmington, Del.; CDL:245878-G)

41408102

Dietrich, R.; McAleer, N. (1989) Hydrolysis of ?Phenyl(U)-carbon 14|Chlorsulfuron and 

?Triazine-2-carbon 14|Chlorsulfuron: Lab Report No. AMR-1455-89.161-1. Unpublished study 

prepared by E.I. du Pont de Nemours & Co., Inc., Agricultural Products Dept. 61 p.

42156701

Dietrich, R.; McAleer, N. (1989) Hydrolysis of ?Phenyl(U)-?carbon 14||Chlorsulfuron and 

?Triazine-2-?carbon 14||Chlorsulfuron: Lab Project Number: AMR-1455-89.161-1. Unpublished study prepared by E.I. du Pont de Nemours & Co., Inc. 61 p.

Photodegradation-water

41408101 Dietrich, R.; McAleer, N. (1989) Photodegradation of ?Phenyl(U)- carbon 14|Chlorsulfuron and 

?Triazine-2-carbon 14|Chlorsulfuron in Water Conducted in Sunlight: Lab Report No. AMR1455-89. Unpublished study prepared by E.I. du Pont de Nemours & Co., Inc., Agricultural 

Products Dept. 45 p.

42156702

Dietrich, R.; McAleer, N. (1989) Photodegradation of ?Phenyl(U)-?carbon 14||Chlorsulfuron and 

?Triazine-2-?carbon 14||Chlorsulfuron in Water Conducted in Sunlight: Lab Project Number: 

AMR-1455-89. Unpublished study prepared by E.I. du Pont de Nemours & Co., Inc. 44 p.

Photodegradation-soil

83947

Han, J.C.Y. (1960?) Photolysis of ^14I-C-Phenyl Labeled DPX-W4189 on Soil: Document No. 

AMR-42-81. (Unpublished study received Sep 1, 1981 under 352-403; submitted by E.I. du Pont 

de Nemours & Co., Wilmington, Del.; CDL:245878-H)

86813

Han, J.C.Y. (19??) Photolysis of ^14IC-Phenyl Labeled DPX-W4189 on Soil: Document No. 

AMR-42-81. (Unpublished study received Nov 13, 1981 under 352-404; submitted by E.I. du 

Pont de Nemours & Co., Inc., Wilmington, Del.; CDL:070470-H)

41721001

Hawkins, D.; Kirkpatrick, D.; Dean, G. (1990) The Photodegradation of ?Carbon 14| 

Chlorsulfuron on a Silty Clay Loam Soil: Lab Pro- ject Number: HRC/DPT 205/90571: AMR1563-89. Unpublished study prepared by Huntingdon Research Centre Ltd. 58 p.

42156703

Hawkins, D.; Kirkpatrick, D.; Dean, G.; et al. (1990) The Photodegradation of ?carbon 

14|Chlorsulfuron on a Silty Clay Loam Soil: Lab Project Number: HRC/DPT 205/90571: AMR1563-89. Unpublished study prepared by Huntingdon Research Centre Ltd. 58 p.

Aerobic soil metabolism

35273

Han, J.C.Y. (19??) Aerobic Soil Metabolism of 14C-Phenyl Labeled DPX-4189: AMR-08-80 C. 

(Unpublished study received Jun 16, 1980 under 352-105; submitted by E.I. du Pont de Nemours 

& Co., Wil- mington, Del.; CDL:099462-T)

35275

Rapisarda, C. (1965?) Microbial Degradation of 14C-Phenyl Labeled DPX-4189 in Soil. 

(Unpublished study received Jun 16, 1980 un- der 352-105; submitted by E.I. du Pont de 

Nemours & Co., Wil- mington, Del.; CDL:099462-V)

83950

Rapisarda, C. (1981) Microbial Degradation of ^14IC-DPX-4189 in Soil: Document No. AMR43-81. (Unpublished study received Sep 1, 1981 under 352-403; submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:245878-K)
53

86814

Rapisarda, C. (1981) Microbial Degradation of [carbon 14]-DPX-4189 in Soil: Document No. 

AMR-43-81. (Unpublished study received Nov 13, 1981 under 352-404; prepared in cooperation 

with Univ. of Delaware, College of Agricultural Sciences, submitted by E.I. du Pont de Nemours 

& Co., Inc., Wilmington, Del.; CDL:070470-J)

42214201

Priester, T. (1991) Aerobic Soil Metabolism of Chlorsulfuron: Lab Project Number: AMR 2213-

91. Unpublished study prepared by E.I. du Pont de Nemours and Co. 305 p.

Anaerobic aquatic metab.

86815

Chrzanowski, R.L. (1980) Degradation of [carbon 14]-DPX-W4189 in Anaerobic Aquatic 

Environments: Document No. AMR-38-81. (Unpublished study received Nov 13, 1981 under 

352-404; prepared in cooperation with Univ. of Delaware, College of Agriculture, submitted by 

E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.; CDL: 070470-K)

Aerobic aquatic metab.

42156704

Chrzanowski, R.; Priester, T. (1991) Degradation of ?carbon 14|-DPX-W4189 in Anaerobic 

Aquatic Environments: Lab Project Number: AMR 38-91. Unpublished study prepared by E.I. 

du Pont de Nemours and Co. 45 p.

Leach/adsorp/desorption

35271

Rapisarda, C.; Shrivastava, S.P.; Butler, L.D. (1978?) Physical Properties of DPX-4189: 

Octanol/Water Partition Ratio, Solubili- ties, and Soil Absorption Data. (Unpublished study 

received Jun 16, 1980 under 352-105; submitted by E.I. du Pont de Nemours & Co., 

Wilmington, Del.; CDL:099462-R)

35272

Chrzanowski, R.L. (1974) Soil Column Absorption Studies with 14C- DPX-4189 Herbicides on 

Soils. (Unpublished study received Jun 16, 1980 under 352-105; submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:099462-S)

83948

Rapisarda, C.; Shrivastava, S.P.; Butler, L.D. (1980?) Physical Properties of DPX-4189: 

Octanol/Water Partition Ratio, Solubilities, and Soil Adsorption Data [K-values and TLC (Rf) 

Values]: Document No. AMR-28-81. (Unpublished study received Sep 1, 1981 under 352-403; 

submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:245878-I)

83949

Chrzanowski, R.L. (1980?) Soil Column Leaching Studies with ?^14IC|-DPX-4189: Document 

No. AMR-26-81. (Unpublished study received Sep 1, 1981 under 352-403; submitted by E.I. du 

Pont de Nemours & Co., Wilmington, Del.; CDL:245878-J)

86816

Chrzanowski, R.L. (1980) Soil Column Leaching Studies with (Carbon-14)|- DPX-4189: 

Document No. AMR-26-81. (Unpublished study received Nov 13, 1981 under 352-404; prepared 

in cooperation with Univ. of Delaware, College of Agricultural Sciences, submitted by E.I. du 

Pont de Nemours & Co., Inc., Wilmington, Del.; CDL:070470-L)

42156705

Priester, T.; Sheftic, G. (1989) Batch Equilibrium (Adsorption/Desorption) with (carbon 14) 

Chlorsulfuron and Soil Thin-Layer Chromatography Studies with (carbon 14)Chlorsulfuron and 

its Major Soil Degradates: Lab Project Number: AMR-1277-88. Unpublished study prepared by 

E. I. du Pont de Nemours & Co., Inc. 58 p.

45371826

Weber, J.; Miller, C. (1999) Organic Chemical Movement Over and Through Soil. Unpublished 

study prepared by North Carolina State University and University of North Carolina. 33 p.
54

46155803

Yeomans, P.; Swales, S. (2000) (Carbon 14) IN-A4098: Adsorption/Desorption in Soil. Project 

Number: DUPONT/3832, 3832, 550/80. Unpublished study prepared by Covance Laboratories, 

Ltd. 52 p.

Terrestrial field dissipation

35274

E.I. du Pont de Nemours & Company (1979) Field Soil Disappearance Studies with 14C-Labeled 

DPX-4189. (Unpublished study received Jun 16, 1980 under 352-105; CDL:099462-U)

86817

Han, J.C.Y. (1981) 14C-DPX-W4189 Soil Disappearance Studies in the Field: Document No. 

AMR-54-81. (Unpublished study received Nov 13, 1981 under 352-404; submitted by E.I. du 

Pont de Nemours & Co., Inc., Wilmington, Del.; CDL:070470-M)

41714401

Dietrich, R.; Taylor, G. (1990) Field Soil Dissipation of (Phenyl (U)-(Carbon 14)) Chlorsulfuron 

and (Triazine-2-(Carbon 14)) Chlosulfuron in Madera, California: Lab Project Number: AMR1417-89: EF-89-03. Unpublished study prepared by E. I. du Pont de Nemours and Co. in 

Association with Pan-Agricultural Laboratories, Inc. 66 p.

42214202

Djanegara, T. (1991) Field Soil Dissipation Studies of Chlorsulfuron: Lab Project Number: 

AMR 2205-91. Unpublished study prepared by E. I. du Pont de Nemours & Co. 229 p.

43421401

Rhodes, B. (1994) Terrestrial Field Soil Dissipation of (carbon 14)-Chlorsulfuron: Lab Project 

Number: AMR 2266-91. Unpublished Study Prepared by DuPont Agricultural products and 

University of Idaho. 99 p.

Confined rotational crop

47459401

Swanson, M. (1988) Confined Accumulation Study of [carbon 14]-Sulfometuron Methyl of 

Rotational Crops. Project Number: AMR/956/87. Unpublished study prepared by DuPont 

Experiment Station Laboratories. 42 p.

Field rotational crop

42214203

Djanegara, T. (1991) Accumulation Studies of Chlorsulfuron in Rotational Crops: Lab Project 

Number: AMR 2242-91. Unpublished study prepared by E. I. du Pont de Nemours & Co. 157 p.

Bioconcentration in fish

42214204

Priester, T. (1991) Fish Accumulation Potential for Chlorsulfuron: Lab Project Number: AMR 

2238-91. Unpublished study prepared by E. I. du Pont de Nemours & Co. 61 p.

83951

Han, J.C.Y. (19??) Residue Studies with [carbon 14]-DPX-4189 in Bluegill Sunfish: Document 

No. AMR-32-81. (Unpublished study re- ceived Sep 1, 1981 under 352-403; submitted by E.I. 

du Pont de Nemours & Co., Wilmington, Del.; CDL:245878-L)

Environmental Chemistry Methods

83954

E.I. du Pont de Nemours & Company, Incorporated (19??) Determina- tion of DPX-4189: 

Reversed-phase Liquid Chromatography (RPLC) Assay Method. Undated method no. C 

298.0282 (R). (Unpublished study received Sep 1, 1981 under 352-EX-109; CDL:245879-E)

43406701

Battelle (1991) Method for the Determination of Chlorsulfuron, DPX-A7881, DPX-F5384, 

DPX-L5300, DPX-M6316, and Metsulfuron Methyl in Groundwater: (Revised) Final Report: 

Lab Project Number: AMR 1335-88. Unpublished study. 66 p.
55

43406702

Battelle (1991) Method for the Determination of Chlorsulfuron, DPX-A7881, DPX-F5384, 

DPX-L5300, DPX-M6316, and Metsulfuron Methyl in Groundwater: Supplement A to Report: 

Lab Project Number: AMR 1335-88. Unpublished study. 38 p.

Non-Guideline

35277

Julis, A.J. (1980) The Effect of DPX-4189 on Microorganisms and Microbial Populations of 

Soils: AMR-13-80. (Unpublished study received Jun 16, 1980 under 352-105; submitted by E.I. 

du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-X)

46017702

Mckelvey, R.; Strek, H.; Carski, H.; et. al. (2003) Registrant Error Corrections and Comments on 

the Agency Document "Environmental Fate and Ecological Effects Risk Assessment for 

Chlorsulfuron". Unpublished study prepared by: E. I. du Pont de Nemours and Co. 95 p.

46128401 McKelvey, R.; Carski, T.; Dulka, J.; et. al. (2003) Registration Error Corrections and Comments 

on the Agency Memorandum Entitled "Spray Drift Risks to Non-Target Plants Associateed with 

Chlorsulfuron Applications". Unpublished study prepared by E. I. Du Pont De Nemours and Co., 

Inc. 42 p.

17.2. Data submitted on Ecological Effects

Avian Single Dose Oral Toxicity

MRID Citation Reference

35263 Hinkle, S.; Twigg, C.J. (1980) Final Report--Acute Oral LD50 Study in Bobwhite 

Quail: Project No. 201-538. (Unpublished study re- ceived Jun 16, 1980 under 352-

105; prepared by Hazleton Labora- tories America, Inc., submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:099462-I) 

35264 Hinkle, S.; Bristol, K.L. (1980) Final Report--Acute Oral LD50 Study in Mallard 

Ducks: Project No. 201-525. (Unpublished study received Jun 16, 1980 under 352-

105; prepared by Hazelton Labo- ratories America, Inc., submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:099462-J) 

Avian Dietary Toxicity

35265 Hinkle, S. (1979) Final Report--Avian Dietary Toxicity (LC50) Study in Bobwhite 

Quail: Project No. 201-523. (Unpublished study re- ceived Jun 16, 1980 under 352-

105; prepared by Hazleton Labora- tories America, Inc., submitted by E.I. du Pont de 

Nemours & Co., Wilmington, Del.; CDL:099462-K) 

35266 Hinkle, S.; Wentz, K.L. (1979) Final Report--Avian Dietary Toxicity (LC50) in 

Mallard Ducks: Project No. 201-524. (Unpublished study received Jun 16, 1980 under 

352-105; prepared by Hazleton Laboratories America, Inc., submitted by E.I. du Pont 

de Nemours & Co., Wilmington, Del.; CDL:099462-L) 

90009 Fink, R.; Beavers, J.B.; Joiner, G.; et al. (1981) Eight-day Die- tary LCI50^--Bobwhite 

Quail: H-12,700-02: Project No. 112-126; HLO-806-81. Final rept. (Unpublished study 

received Dec 28, 1981 under 352-404; prepared by Wildlife International, Ltd., 

submitted by E.I. du Pont de Nemours & Co., Inc., Wilmington, Del.; CDL:070534-B) 

Avian Reproduction

42634001 Beavers, J.; Foster, J.; Lynn, S.; et al. (1992) H-18,053 (Chlorsulfuron): A Onegeneration Reproduction Study with the Northern Bobwhite (Colinus virginianus): 

Lab Project Number: 112-266: 564-92. Unpublished study prepared by Wildlife 

International Ltd. 185 p. 

42634002 Beavers, J.; Foster, J.; Lynn, S.; et al. (1992) H-18,053 (Chlorsulfuron): A One-
56

Generation Reproduction Study with the Mallard (Anas platyrhynchos): Lab Project 

Number: 112-267: 565-92. Unpublished study prepared by Wildlife International 

Ltd. 185 p. 

Acute Toxicity to Freshwater Fish

35258 Smith, E.J. (1979) 96-Hour LC50 to Bluegill Sunfish: Haskell Labo- ratory Report 

No. 385-79. (Unpublished study received Jun 16, 1980 under 352-105; submitted by 

E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-D) 

35259 Smith, E.J. (1979) 96-Hour LC50 to Bluegill Sunfish: Haskell Labo- ratory Report 

No. 386-79. (Unpublished study received Jun 16, 1980 under 352-105; submitted by 

E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-E) 

35260 Smith, E.J. (1979) 96-Hour LC50 to Fathead Minnows: Haskell Labora- tory Report 

No. 384-79. (Unpublished study received Jun 16, 1980 under 352-105; submitted by 

E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-F) 

35261 Smith, E.J. (1979) 96-Hour LC50 to Channel Catfish: Haskell Labora- tory Report 

No. 856-79. (Unpublished study received Jun 16, 1980 under 352-105; submitted by 

E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-G) 

45202909 Grande, M.; Andersen, S.; Berge, D. (1994) Effects of pesticides on fish: 

experimental and field studies. Norwegian Journal of Agricultural Sciences Suppl. 

13: 195-209. 

47642101 Baummer, J. (2008) IN-D5293-016: Static, Acute, 24-Hours Lead Optimization 

Screen Using Fathead Minnows, Pimephales promelas. Project Number: 

DUPONT/18071/206, 18071, 28795. Unpublished study prepared by E.I. du Pont de 

Nemours and Company. 6 p.

Acute Toxicity to Freshwater Invertebrates

35262 Goodman, N.C. (1979) 48-Hour LC50 to~Daphnia magna~?: Haskell Lab- oratory 

Report No. 152-79. (Unpublished study received Jun 16, 1980 under 352-105; 

submitted by E.I. du Pont de Nemours & Co., Wilmington, Del.; CDL:099462-H) 

Acute Toxicity to Estuarine/Marine Organisms

41976401 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 

(Chlorsulfuron) to the Sheepshead Minnow, Cyprindon variegatus: Lab Project 

Number: MR-4581-866: 516-91: 9130-DU. Unpublished study prepared by 

EnviroSystems Division. 31 p. 

41976402 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 

(Chlorsulfuron) to the Mysid, Mysidopsis bahia: Lab Project Num- ber: MR-4581-

866: 523-91: 9131-DU. Unpublished study prepared by EnviroSystems Division. 31 

p. 

41976403 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 

(Chlorsulfuron) to Bivalve Mollusc Embryos and Larvae: Lab Proj- ect Number: 

MR-4581-866: 524-91: 9132-DU. Unpublished study prepared by EnviroSystems 

Division. 31 p. 

42328601 Ward, T.; Boeri, R. (1991) Static Acute Toxicity of DPX-W4189-165 

(Chlorsulfuron) to Bivalve Mollusc Embryos and Larvae: Lab Project Number: 524-

91: MR-4581-866. Unpublished study prepared by EnviroSystems Division, 

Resource Analysts, Inc. 31 p. 

Fish Early Life Stage/Aquatic Invertebrate Life Cycle Studies

41976404 Ward, T.; Boeri, R. (1989) Chronic Toxicity of DPX-W4189-94 to Daphnia 
57

magna: Lab Project Number: 4581-655: 87-89. Unpublished study prepared by 

E.I. du Pont de Nemours and Co. 27 p. 

41976405 Pierson, K. (1991) Flow-Through 77 Day Toxicity of DPX-W4189-170 to 

Embryo and Larval Rainbow Trout, Oncorhynchus mykiss: Lab Proj- ect 

Number: 494-91: MR-4581-866. Unpublished study prepared by E.I. du Pont de 

Nemours and Co. 471 p. 

41976408 Hutton, D. (1991) Chronic Toxicity of DPX-W4189-94 to Daphnia magna Lab 

Project Number: 4581-655: 87-89. Unpublished study prepared by E.I. du Pont 

de Nemours and Co. 92 p. 

42309701 Hutton, D. (1992) Chronic Toxicity of DPX-W4189-94 to Daphnia magna: 

Supplement #1: Lab Project Number: 87-89. Unpublished study prepared by 

E.I. du Pont de Nemours and Co. 8 p. 

Seed Germination/Seedling Emergence and Vegetative Vigor

42201001 McKelvey, R.; Kuratle, H. (1991) Influence of Chlorsulfuron on Seed 

Germination, Seedling Emergence and Vegetative Vigor of Several Terrestrial 

Plants: Lab Project Number: AMR 2070-91. Unpublished study prepared by E.I. 

du Pont de Nemours and Co. 235 p. 

42587201 McKelvey, R.; Kuratle, H. (1992) Influence of Chlorsulfuron on Seed 

Germination, Seedling Emergence, and Vegetative Vigor of Several Terrestrial 

Plants: Revision No. 1: Lab Project Number: AMR 2070-91. Unpublished study 

prepared by E.I. du Pont de Nemours and Co. 235 p. 

Aquatic plant growth Tier 1

45088212 Fairchild, J.; Ruessler, D.; Haverland, P. et al. (1996) Comparative Sensitivity of 

Selenastrum capricornutum and Lemna minor to Sixteen Herbicides. Archives of 

Environmental Contamination and Toxicology 32:353-357. 

46045201 Sloman, T. (2002) Chlorsulfuron (DPX-W4189) 75WG: Influence on Growth 

and Growth Rate of the Green Alga Selenastrum capricornutum. Project 

Number: DUPONT/10063, 10063. Unpublished study prepared by Dupont 

Haskell Laboratory. 49 p.

46045202 Sloman, T. (2002) Chlorsulfuron (DPX-W4189) 75WG: Influence on Growth 

and Reproduction of Lemna gibba. Project Number: DUPONT/10064, 10064, 

E1415/91. Unpublished study prepared by Dupont Haskell Laboratory. 49 p.

Seed germination/seedling emergence and vegetative vigor

42201001 McKelvey, R.; Kuratle, H. (1991) Influence of Chlorsulfuron on Seed 

Germination, Seedling Emergence and Vegetative Vigor of Several Terrestrial 

Plants: Lab Project Number: AMR 2070-91. Unpublished study prepared by 

E.I. du Pont de Nemours and Co. 235 p. 

42587201 McKelvey, R.; Kuratle, H. (1992) Influence of Chlorsulfuron on Seed 

Germination, Seedling Emergence, and Vegetative Vigor of Several Terrestrial 

Plants: Revision No. 1: Lab Project Number: AMR 2070-91. Unpublished 

study prepared by E.I. du Pont de Nemours and Co. 235 p. 

Terrestrial plant toxicity, Tier 1 (seeding emergence)

46361801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Study to Investigate the Effects on Seedling Emergence and 

Growth of Ten Terrestrial Plants Following Soil Exposure. Project Number: 

112/541, 14901, 1495. Unpublished study prepared by Wildlife International, 

Ltd. 264 p.

Terrestrial plant toxicity, Tier 1 (vegetative vigor)
58

46326801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Study to Investigate the Effects on Vegetative Vigor of Ten 

Terrestrial Plants Following Foliar Exposure. Project Number: 112/542, 

DUPONT/13552, 14901. Unpublished study prepared by Wildlife 

International, Ltd. 191 p.

47845101 Porch, J.; Martin, K. (2009) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Rate Response Study to Investigate the Comparative Effects on 

Vegetative Vigor of Sugarbeet Following Foliar Exposure by High Volume 

and Volume Reduction Methods. Project Number: 112/622A, 

DUPONT/21982, 17791/1496. Unpublished study prepared by Wildlife 

International, Ltd. 77 p.

Seedling emergence, Tier II

46361801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Study to Investigate the Effects on Seedling Emergence and 

Growth of Ten Terrestrial Plants Following Soil Exposure. Project Number: 

112/541, 14901, 1495. Unpublished study prepared by Wildlife International, 

Ltd. 264 p.

Vegetative vigor, Tier II

46326801 Porch, J.; Martin, K. (2004) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Study to Investigate the Effects on Vegetative Vigor of Ten 

Terrestrial Plants Following Foliar Exposure. Project Number: 112/542, 

DUPONT/13552, 14901. Unpublished study prepared by Wildlife 

International, Ltd. 191 p.

47845101 Porch, J.; Martin, K. (2009) Chlorsulfuron (DPX-W4189) 75WG: A 

Greenhouse Rate Response Study to Investigate the Comparative Effects on 

Vegetative Vigor of Sugarbeet Following Foliar Exposure by High Volume and 

Volume Reduction Methods. Project Number: 112/622A, DUPONT/21982, 

17791/1496. Unpublished study prepared by Wildlife International, Ltd. 77 p.

Aquatic plant growth

42186801 Blasberg, J.; Hicks, S.; Stratton, J. (1991) Acute Toxicity of Chlorsulfuron to 

Selenastrum capricornutum Printz: Final Report: Lab Project Number: AMR2081-91: 39427. Unpublished study prepared by ABC Laboratories, Inc. 33 

p. 

45832901 Boeri, R.; Wyskiel, D.; Ward, T. (2002) Chlorsulfuron (DPX-W4189) 

Technical: Influence on Growth Rate of the Duckweed, Lemna gibba: Lab 

Project Number: 2042-DU: DUPONT-4468: ASTM E1415-91. Unpublished 

study prepared by T.R. Wilbury Laboratories. 38 p. 

45832902 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) 

Technical: Influence on Growth and Growth Rate of the Alga, Skeletonema 

costatum: Lab Project Number: 2043-DU: DUPONT-4465. Unpublished 

study prepared by T.R. Wilbury Laboratories. 37 p. 

45832903 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) 

Technical: Influence on Growth and Growth Rate of Alga, Anabaena flosaquae: Lab Project Number: DUPONT-4466: 2044-DU. Unpublished study 

prepared by T.R. Wilbury Laboratories. 38 p. 

45832904 Boeri, R.; Wyskiel, D.; Ward, T. (2001) Chlorsulfuron (DPX-W4189) 

Technical: Influence on Growth and Growth Rate of the Alga, Navicula 

pelliculosa: Lab Project Number: DUPONT-4467: 2045-DU. Unpublished 

study prepared by T.R. Wilbury Laboratories. 37 p. 
59

Honeybee Toxicity

42129902 Hoxter, K.; Lynn, S. (1991) H (No.)18,053: An Acute Contact Toxici- ty Study 

with the Honey Bee: Lab Project Number: 112-260: 690-91. Unpublished study 

prepared by Wildlife International Ltd. 15 p. 
60

Appendix A. List of Registered Products Containing Chlorsulfuron and Percent Active 

Ingredients

# EPA Reg. 

# Name Percent Chlorsulfuron

1 352-516 DUPONT CHLORSULFURON TECHNICAL 98

2 228-375 RIVERDALE CORSAIR SELECTIVE 

HERBICIDE 75

3 228-600 NUP 08136 15

48 Metsulfuron

4 228-672 NUFARM CHLORSULF SPC 75 WDG 

HERBICIDE 75

5 228-673 ETI 123 01 H-D2 75

6 228-676 ETI 122 01 H-D 62.5

12.5 Metsulfuron

7 352-445 DUPONT FINESSE HERBICIDE 62.5

12.5 Metsulfuron

8 352-522 DUPONT GLEAN FERTILIZER 

COMPATIBLE HERBICIDE 75

9 352-645 DUPONT LANDMARK XP HERBICIDE 25

50 Sulfometuron

10 352-653 DUPONT GLEAN XP HERBICIDE 75

11 352-654 DUPONT TELAR XP HERBICIDE 75

12 352-669 DUPONT CIMARRON X-TRA HERBICIDE 37.5

30 Metsulfuron

13 352-670 DUPONT CIMARRON PLUS HERBICIDE 15

48 Metsulfuron

14 352-712 DUPONT THROTTLE MP HERBICIDE

9

48 Sulfentrazone

18 Sulfometuron

15 352-718 DUPONT FINESSE GRASS & BROADLEAF 

HERBICIDE

25

46.7 Flucarbazone-sodium

16 352-725 DUPONT THROTTLE XP HERBICIDE

9

18 Sulfometuron

48 Sulfentrazone

17 352-827 DUPONT FINESSE CEREAL AND 

FALLOW HERBICIDE

62.5

12.5 Metsulfuron

18 352-IUL DUPONT PLAINVIEW HERBICIDE

9.4

18.7 Sulfmeturon

31.2 Aminocyclopyrachlor

19 352-846 DUPONT PERSPECTIVE HERBICIDE 15.8

39.5 Aminocyclopyrachlor

20 352-ILR DUPONT PERSPECTIVE R&P HERBICIDE 15.8
61

# EPA Reg. 

# Name Percent Chlorsulfuron

39.5 Aminocyclopyrachlor

21 34704-

1004 LPI CHLOR-METSUL 62.512.5 Metsulfuron

22 67760-79 CHEMINOVA CHLORSULFURON 

TECHNICAL 98.3

23 67760-80 CHISUM HERBICIDE 15

48 Metsulfuron

24 67760-81 REPORT HERBICIDE 75

25 67760-82 REPORT EXTRA HERBICIDE 62.5

12.5 Metsulfuron

26 67760-98 CHI-CHLORSUL NC-75 HERBICIDE 75

27 71368-91 NUP 08135 62.5

12.5 Metsulfuron

28 71368-92 NUP 08134 75

29 71368-94 NUP-08111 FC HERBICIDE 75

30 71368-95 NUP-08113 HERBICIDE 15

48 Metsulfuron

31 71368-96 NUP-08111 HERBICIDE 75

32 71368-97 NUP-08112 HERBICIDE 62.5

12.5 Metsulfuron

33 81927-43 ALLIGARE CHLORSULFURON 75 75

34 84930-17 ARC CHLORMET HERBICIDE 62.5

12.5 Metsulfuron

35 85588-9 CHLORMET HERBICIDE 62.5

12.5 Metsulfuron

36 85588-17 CHLORMET XP HERBICIDE 62.5

12.5 Metsulfuron
62

Appendix B. ECOSAR and ASTER Output

Chlorsulfuron

SMILES : CLc1ccccc1S(=O)(=O)NC(=O)Nc2nc(nc(OC)n2)C

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C12 H12 CL1 N5 O4 S1 

MOL WT : 357.77

Log Kow: 2.26 (KowWin estimate)

Melt Pt: 

Wat Sol: 3.1E+004 mg/L (experimental database)

ECOSAR v1.00 Class(es) Found

------------------------------

Triazines

Amides 

Sulfonyl Ureas 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Triazines : Fish 96-hr LC50 73.573

Triazines : Daphnid 48-hr LC50 56.449

Triazines : Green Algae 96-hr EC50 19.763

Triazines : Fish ChV 15.601 !

Triazines : Daphnid 21-day ChV 6.477

Triazines : Green Algae ChV 6.232

Amides : Fish 96-hr LC50 28.568

Amides : Daphnid 48-hr LC50 17.617

Amides : Green Algae 96-hr EC50 0.664

Amides : Fish ChV 0.169

Amides : Daphnid ChV 0.232 !

Amides : Green Algae ChV 0.598

Sulfonyl Ureas : Daphnid 48-hr LC50 54.403

Sulfonyl Ureas : Green Algae 96-hr EC50 0.040

Sulfonyl Ureas : Daphnid ChV 5.398 !

Sulfonyl Ureas : Green Algae ChV 0.010 !

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 165.297

(Baseline Toxicity) : Daphnid 48-hr LC50 98.456

 : Green Algae 96-hr EC50 47.272

 : Fish ChV 15.601

 : Daphnid ChV 9.526

 : Green Algae ChV 17.948

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR
63

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Sulfonyl Ureas :

---------------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)
64

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

ODMC

SMILES : CLc1c(cccc1)S(=O)(=O)NC(=O)Nc2nc(nc(n2)C)O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C11 H10 CL1 N5 O4 S1 

MOL WT : 343.75

Log Kow: 1.20 (KowWin estimate)

Melt Pt: 

Wat Sol: 632.2 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Phenols

Triazines

Amides 

Sulfonyl Ureas 

Phenol Amines 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Phenols : Fish 96-hr LC50 195.832

Phenols : Fish 14-day LC50 1324.549 *

Phenols : Daphnid 48-hr LC50 50.743

Phenols : Green Algae 96-hr EC50 252.136

Phenols : Fish 30-day ChV 11.325

Phenols : Fish 60-day ChV 0.010

Phenols : Daphnid 21-day ChV 9.666

Phenols : Green Algae ChV 119.649

Phenols : Fish (SW) 96-hr LC50 233.334

Phenols : Earthworm 14-day LC50 675.142 *

Phenols : Lemna Gibba 7-day EC50 209.243

Triazines : Fish 96-hr LC50 1368.476 *

Triazines : Daphnid 48-hr LC50 470.759

Triazines : Green Algae 96-hr EC50 82.778

Triazines : Fish ChV 120.468 !

Triazines : Daphnid 21-day ChV 33.238

Triazines : Green Algae ChV 19.025

Amides : Fish 96-hr LC50 188.348

Amides : Daphnid 48-hr LC50 80.609

Amides : Green Algae 96-hr EC50 1.258

Amides : Fish ChV 1.113
65

Amides : Daphnid ChV 1.063 !

Amides : Green Algae ChV 0.574

Sulfonyl Ureas : Daphnid 48-hr LC50 286.408

Sulfonyl Ureas : Green Algae 96-hr EC50 0.038

Sulfonyl Ureas : Daphnid ChV 26.794 !

Sulfonyl Ureas : Green Algae ChV 0.010 !

Phenol Amines : Fish 96-hr LC50 27.068

Phenol Amines : Daphnid 48-hr LC50 2.656

Phenol Amines : Green Algae 96-hr EC50 11.734

Phenol Amines : Fish ChV 1.608 !

Phenol Amines : Daphnid 21-day ChV 0.999

Phenol Amines : Green Algae ChV 1.943

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 1246.913 *

(Baseline Toxicity) : Daphnid 48-hr LC50 653.564 *

 : Green Algae 96-hr EC50 203.322

 : Fish ChV 120.468

 : Daphnid ChV 52.447

 : Green Algae ChV 63.639

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Phenols:

-------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 7.0 (Fish 96-hr LC50, Daphnid LC50)

Maximum LogKow: 6.4 (Fish 14-day LC50, Earthworm, Lemna)

Maximum LogKow: 7.0 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum LogKow: 5.0 (Fish (SW) 96-hr LC50, Mysid)

Maximum Mol Wt: 1000

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is
66

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Sulfonyl Ureas :

---------------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Phenol Amines :

--------------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50)
67

Maximum LogKow: 7.0 (Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

ROC

SMILES : c1cccc(c1CL)S(NC(=O)(NC(=O)(NC(=O)(NCC))))(=O)=O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C11 H13 CL1 N4 O5 S1 

MOL WT : 348.76

Log Kow: 2.86 (KowWin estimate)

Melt Pt: 

Wat Sol: 22.79 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Imides

Amides 

Sulfonyl Ureas 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Imides : Fish 96-hr LC50 21.653

Imides : Daphnid 48-hr LC50 25.630 *

Imides : Green Algae 96-hr EC50 2.570

Imides : Fish ChV 2.106 !

Imides : Daphnid ChV 2.341 !

Imides : Green Algae ChV 1.311

Amides : Fish 96-hr LC50 9.391

Amides : Daphnid 48-hr LC50 7.117

Amides : Green Algae 96-hr EC50 0.442

Amides : Fish ChV 0.056

Amides : Daphnid ChV 0.094 !

Amides : Green Algae ChV 0.583

Sulfonyl Ureas : Daphnid 48-hr LC50 20.305

Sulfonyl Ureas : Green Algae 96-hr EC50 0.039

Sulfonyl Ureas : Daphnid ChV 2.083 !

Sulfonyl Ureas : Green Algae ChV 0.010 !

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 50.361 *

(Baseline Toxicity) : Daphnid 48-hr LC50 32.241 *
68

 : Green Algae 96-hr EC50 19.776

 : Fish ChV 4.691

 : Daphnid ChV 3.467

 : Green Algae ChV 8.373

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Imides:

------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Sulfonyl Ureas :

---------------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.
69

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

CPSU

SMILES : c1cccc(c1CL)S(NON)(=O)=O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C6 H7 CL1 N2 O3 S1 

MOL WT : 222.65

Log Kow: -1.74 (KowWin estimate)

Melt Pt: 

Wat Sol: 1E+006 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Aliphatic Amines

Amides 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Aliphatic Amines : Fish 96-hr LC50 6935.824

Aliphatic Amines : Daphnid 48-hr LC50 323.221

Aliphatic Amines : Green Algae 96-hr EC50 41.178

Aliphatic Amines : Fish ChV 87.064

Aliphatic Amines : Daphnid ChV 0.061

Aliphatic Amines : Green Algae ChV 44.049

Aliphatic Amines : Fish (SW) 96-hr LC50 7161.330

Aliphatic Amines : Mysid Shrimp (SW) 96-hr LC50 336.394

Aliphatic Amines : Green Algae (SW) 96-hr EC50 40.947

Aliphatic Amines : Fish (SW) ChV 87.064

Aliphatic Amines : Mysid Shrimp (SW) ChV 0.061

Aliphatic Amines : Green Algae (SW) ChV 37.399

Amides : Fish 96-hr LC50 25929.938

Amides : Daphnid 48-hr LC50 4016.072

Amides : Green Algae 96-hr EC50 5.382

Amides : Fish ChV 153.286
70

Amides : Daphnid ChV 52.979 !

Amides : Green Algae ChV 0.372

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 2.5e+005

(Baseline Toxicity) : Daphnid 48-hr LC50 91699.672

 : Green Algae 96-hr EC50 8528.177

 : Fish ChV 25745.279

 : Daphnid ChV 4373.101

 : Green Algae ChV 1559.670

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Aliphatic Amines:

----------------

 For Fish 96-hr LC50: For aliphatic amines with log Kow greater than 7.0,

a test duration of greater than 96 hrs may be required for proper

expression of toxicity. Also, if the toxicity value obtained by the use

of this equation exceeds the water solubility (measured or estimated),

mortalities greater than 50% would not be expected in a saturated

solution during an exposure period of 96 hrs.

 For Daphnid 48-hr LC50: For aliphatic amines with log Kow greater than

5.0, a test duration of greater than 48 hrs may be required for proper

expression of toxicity. Also, if the toxicity value obtained by the use

of this equation exceeds the water solubility (measured or estimated),

significant mortalities would not be expected in a saturated solution 

during an exposure period of 48 hrs.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 7, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Mysid Shrimp Acute Toxicity Values: If the log Kow of the chemical is

greater than 6, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Fish and Daphnid Chronic Toxicity Values: If the log Kow of the chemical

is greater than 8.0, or if the compound is solid and the ChV exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For Green Algae Chronic Toxicity Values: If the log Kow of the chemical

is greater than 7.0, or if the compound is solid and the ChV exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 6.0 (Fish, Mysid LC50)

Maximum LogKow: 5.0 (Daphnid LC50)
71

Maximum LogKow: 7.0 (Green Algae EC50)

Maximum LogKow: 8.0 (Fish, Daphnid ChV)

Maximum LogKow: 7.0 (Green Algae ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Chlorosulfonamide

SMILES : c1cccc(c1CL)S(N)(=O)=O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C6 H6 CL1 N1 O2 S1 

MOL WT : 191.63

Log Kow: 1.01 (KowWin estimate)

Melt Pt: 

Wat Sol: 1.126E+004 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Amides 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Amides : Fish 96-hr LC50 148.411

Amides : Daphnid 48-hr LC50 59.482

Amides : Green Algae 96-hr EC50 0.792

Amides : Fish ChV 0.877

Amides : Daphnid ChV 0.785 !

Amides : Green Algae ChV 0.320

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 1006.577

(Baseline Toxicity) : Daphnid 48-hr LC50 515.613

 : Green Algae 96-hr EC50 148.375

 : Fish ChV 97.657

 : Daphnid ChV 40.009

 : Green Algae ChV 44.857
72

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

OHCSM

SMILES : c1cc(cc(c1CL)S(N)(=O)=O)O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C6 H6 CL1 N1 O3 S1 

MOL WT : 207.63

Log Kow: 0.53 (KowWin estimate)

Melt Pt: 

Wat Sol: 5.311E+004 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Phenols

Amides 

Phenol Amines 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Phenols : Fish 96-hr LC50 366.152

Phenols : Fish 14-day LC50 3077.110

Phenols : Daphnid 48-hr LC50 73.492

Phenols : Green Algae 96-hr EC50 389.742

Phenols : Fish 30-day ChV 17.217

Phenols : Fish 60-day ChV 0.006

Phenols : Daphnid 21-day ChV 14.014

Phenols : Green Algae ChV 186.525

Phenols : Fish (SW) 96-hr LC50 655.371
73

Phenols : Earthworm 14-day LC50 766.474

Phenols : Lemna Gibba 7-day EC50 482.513

Amides : Fish 96-hr LC50 385.550

Amides : Daphnid 48-hr LC50 130.909

Amides : Green Algae 96-hr EC50 1.168

Amides : Fish ChV 2.279

Amides : Daphnid ChV 1.727 !

Amides : Green Algae ChV 0.347

Phenol Amines : Fish 96-hr LC50 29.939

Phenol Amines : Daphnid 48-hr LC50 2.059

Phenol Amines : Green Algae 96-hr EC50 12.699

Phenol Amines : Fish ChV 2.376 !

Phenol Amines : Daphnid 21-day ChV 1.235

Phenol Amines : Green Algae ChV 1.905

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 2779.821

(Baseline Toxicity) : Daphnid 48-hr LC50 1343.641

 : Green Algae 96-hr EC50 317.504

 : Fish ChV 272.574

 : Daphnid ChV 95.772

 : Green Algae ChV 87.931

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Phenols:

-------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 7.0 (Fish 96-hr LC50, Daphnid LC50)

Maximum LogKow: 6.4 (Fish 14-day LC50, Earthworm, Lemna)

Maximum LogKow: 7.0 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum LogKow: 5.0 (Fish (SW) 96-hr LC50, Mysid)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------
74

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Phenol Amines :

--------------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50)

Maximum LogKow: 7.0 (Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

TA

SMILES : c1(nc(nc(n1)C)N)OC

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C5 H8 N4 O1 

MOL WT : 140.15

Log Kow: 1.26 (KowWin estimate)

Melt Pt: 

Wat Sol: 6982 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Anilines (Aromatic Amines)

Triazines

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Anilines (Aromatic Amines) : Fish 96-hr LC50 49.036

Anilines (Aromatic Amines) : Fish 14-day LC50 93.947

Anilines (Aromatic Amines) : Daphnid 48-hr LC50 1.861

Anilines (Aromatic Amines) : Green Algae 96-hr EC50 7.741

Anilines (Aromatic Amines) : Fish ChV 0.206

Anilines (Aromatic Amines) : Daphnid ChV 0.036

Anilines (Aromatic Amines) : Green Algae ChV 5.013

Triazines : Fish 96-hr LC50 474.380

Triazines : Daphnid 48-hr LC50 170.514
75

Triazines : Green Algae 96-hr EC50 31.135

Triazines : Fish ChV 43.819 !

Triazines : Daphnid 21-day ChV 12.364

Triazines : Green Algae ChV 7.281

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 454.133

(Baseline Toxicity) : Daphnid 48-hr LC50 239.704

 : Green Algae 96-hr EC50 76.364

 : Fish ChV 43.819

 : Daphnid ChV 19.433

 : Green Algae ChV 24.156

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Anilines (Aromatic Amines):

--------------------------

 For Fish Acute Toxicity Values: 2,3,5,6-Tetrachloroaniline is 19 times

more toxic than predicted by this SAR. Tetrabromoaniline may be more toxic

than predicted by this SAR as well.

 For Daphnid and Green Algae Toxicity Values: Tetrachloro- and tetrabromaniline may be 20 times toxic than predicted by this SAR.

 N-Substituted anilines are less toxic than predicted by these SARs;

for these compounds, Neutral Organic SARs are used.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >7.8 (Fish 96-hr LC50, Daphnid 48-h LC50)

Maximum LogKow: >3.7 (Fish 14-day LC50)

Maximum LogKow: >4 (Green Algae 96-hr EC50 and ChV)

Maximum LogKow: >4.3 (Fish ChV)

Maximum LogKow: >2.4 (Daphnid ChV)

Maximum Mol Wt: 1000

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility
76

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

OHTA

SMILES : c1(nc(nc(n1)C)N)O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C4 H6 N4 O1 

MOL WT : 126.12

Log Kow: 0.21 (KowWin estimate)

Melt Pt: 

Wat Sol: 6.36E+004 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Anilines (Aromatic Amines)

Phenols

Triazines

Phenol Amines 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Anilines (Aromatic Amines) : Fish 96-hr LC50 156.785

Anilines (Aromatic Amines) : Fish 14-day LC50 1173.842

Anilines (Aromatic Amines) : Daphnid 48-hr LC50 2.720

Anilines (Aromatic Amines) : Green Algae 96-hr EC50 8.773

Anilines (Aromatic Amines) : Fish ChV 1.057

Anilines (Aromatic Amines) : Daphnid ChV 0.072

Anilines (Aromatic Amines) : Green Algae ChV 6.142

Phenols : Fish 96-hr LC50 387.619

Phenols : Fish 14-day LC50 3624.494

Phenols : Daphnid 48-hr LC50 68.620

Phenols : Green Algae 96-hr EC50 375.745

Phenols : Fish 30-day ChV 16.463

Phenols : Fish 60-day ChV 0.004

Phenols : Daphnid 21-day ChV 13.092

Phenols : Green Algae ChV 180.578

Phenols : Fish (SW) 96-hr LC50 847.462

Phenols : Earthworm 14-day LC50 634.912
77

Phenols : Lemna Gibba 7-day EC50 566.281

Triazines : Fish 96-hr LC50 8264.440

Triazines : Daphnid 48-hr LC50 1331.906

Triazines : Green Algae 96-hr EC50 122.145

Triazines : Fish ChV 316.924 !

Triazines : Daphnid 21-day ChV 59.425

Triazines : Green Algae ChV 20.817

Phenol Amines : Fish 96-hr LC50 24.484

Phenol Amines : Daphnid 48-hr LC50 1.414

Phenol Amines : Green Algae 96-hr EC50 10.275

Phenol Amines : Fish ChV 2.241 !

Phenol Amines : Daphnid 21-day ChV 1.067

Phenol Amines : Green Algae ChV 1.468

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 3208.659

(Baseline Toxicity) : Daphnid 48-hr LC50 1490.360

 : Green Algae 96-hr EC50 307.638

 : Fish ChV 316.924

 : Daphnid ChV 100.217

 : Green Algae ChV 80.224

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Anilines (Aromatic Amines):

--------------------------

 For Fish Acute Toxicity Values: 2,3,5,6-Tetrachloroaniline is 19 times

more toxic than predicted by this SAR. Tetrabromoaniline may be more toxic

than predicted by this SAR as well.

 For Daphnid and Green Algae Toxicity Values: Tetrachloro- and tetrabromaniline may be 20 times toxic than predicted by this SAR.

 N-Substituted anilines are less toxic than predicted by these SARs;

for these compounds, Neutral Organic SARs are used.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >7.8 (Fish 96-hr LC50, Daphnid 48-h LC50)

Maximum LogKow: >3.7 (Fish 14-day LC50)

Maximum LogKow: >4 (Green Algae 96-hr EC50 and ChV)

Maximum LogKow: >4.3 (Fish ChV)

Maximum LogKow: >2.4 (Daphnid ChV)

Maximum Mol Wt: 1000

Phenols:

-------
78

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 7.0 (Fish 96-hr LC50, Daphnid LC50)

Maximum LogKow: 6.4 (Fish 14-day LC50, Earthworm, Lemna)

Maximum LogKow: 7.0 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum LogKow: 5.0 (Fish (SW) 96-hr LC50, Mysid)

Maximum Mol Wt: 1000

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Phenol Amines :

--------------

 For All Acute and Chronic Toxicity Values: If the log Kow of the chemical

is greater than the value listed below, or if the compound is solid and the

LC50, EC50 or ChV exceeds the water solubility by 10X, no effects at

saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50)

Maximum LogKow: 7.0 (Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)
79

Maximum Mol Wt: 1000

DT

SMILES : c1(nc(nc(n1)O)C)O

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C4 H5 N3 O2 

MOL WT : 127.10

Log Kow: 0.89 (KowWin estimate)

Melt Pt: 

Wat Sol: 1.652E+004 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Triazines

Phenols, Poly 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Triazines : Fish 96-hr LC50 1235.114

Triazines : Daphnid 48-hr LC50 333.698

Triazines : Green Algae 96-hr EC50 47.687

Triazines : Fish ChV 83.438 !

Triazines : Daphnid 21-day ChV 20.356

Triazines : Green Algae ChV 9.964

Phenols, Poly : Fish 96-hr LC50 53.625

Phenols, Poly : Daphnid 48-hr LC50 382.571

Phenols, Poly : Green Algae 96-hr EC50 1.358

Phenols, Poly : Fish 30-day ChV 20.450

Phenols, Poly : Daphnid 21-day ChV 153.074

Phenols, Poly : Green Algae ChV 0.719

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 857.570

(Baseline Toxicity) : Daphnid 48-hr LC50 432.514

 : Green Algae 96-hr EC50 118.070

 : Fish ChV 83.438

 : Daphnid ChV 32.807

 : Green Algae ChV 34.868

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical
80

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Phenols, Poly :

--------------

 For Fish Acute Toxicity Values: If the log Kow of the chemical is

greater than 7.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Daphnid Acute Toxicity Values: If the log Kow of the chemical is

greater than 5.5, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 7.0 (Fish LC50)

Maximum LogKow: 5.5 (Daphnid LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

TU

SMILES : c1(nc(nc(n1)OC)NC(=O)(N))C
81

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C6 H9 N5 O2 

MOL WT : 183.17

Log Kow: 0.89 (KowWin estimate)

Melt Pt: 

Wat Sol: 9174 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Substituted Ureas

Triazines

Amides 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Substituted Ureas : Fish 96-hr LC50 335.991

Substituted Ureas : Daphnid 48-hr LC50 748.598

Substituted Ureas : Green Algae 96-hr EC50 0.131

Substituted Ureas : Fish ChV 4.645

Substituted Ureas : Daphnid ChV 51.317

Substituted Ureas : Green Algae ChV 0.038 !

Triazines : Fish 96-hr LC50 1745.865

Triazines : Daphnid 48-hr LC50 474.167

Triazines : Green Algae 96-hr EC50 68.066

Triazines : Fish ChV 118.619 !

Triazines : Daphnid 21-day ChV 29.016

Triazines : Green Algae ChV 14.251

Amides : Fish 96-hr LC50 177.021

Amides : Daphnid 48-hr LC50 68.031

Amides : Green Algae 96-hr EC50 0.819

Amides : Fish ChV 1.046

Amides : Daphnid ChV 0.897 !

Amides : Green Algae ChV 0.306

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 1219.356

(Baseline Toxicity) : Daphnid 48-hr LC50 615.494

 : Green Algae 96-hr EC50 168.497

 : Fish ChV 118.619

 : Daphnid ChV 46.744

 : Green Algae ChV 49.822

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.
82

Substituted Ureas:

-----------------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Triazines:

---------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:
83

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

AB

SMILES : O=C(N)(NC(=O)(NC(=O)(C)))

CHEM : 

CAS Num: 

ChemID1: 

ChemID2: 

ChemID3: 

MOL FOR: C4 H7 N3 O3 

MOL WT : 145.12

Log Kow: -0.43 (KowWin estimate)

Melt Pt: 

Wat Sol: 1.86E+005 mg/L (WskowWin estimate)

ECOSAR v1.00 Class(es) Found

------------------------------

Imides

Amides 

 Predicted

ECOSAR Class Organism Duration End Pt mg/L (ppm)

=========================== ================== ======== ====== ==========

Imides : Fish 96-hr LC50 3420.288

Imides : Daphnid 48-hr LC50 3031.061

Imides : Green Algae 96-hr EC50 17.170

Imides : Fish ChV 343.458 !

Imides : Daphnid ChV 173.596 !

Imides : Green Algae ChV 9.741

Amides : Fish 96-hr LC50 1564.157

Amides : Daphnid 48-hr LC50 380.466

Amides : Green Algae 96-hr EC50 1.517

Amides : Fish ChV 9.247

Amides : Daphnid ChV 5.019 !

Amides : Green Algae ChV 0.242

=========================== ================== ======== ====== ==========

Neutral Organic SAR : Fish 96-hr LC50 12753.230

(Baseline Toxicity) : Daphnid 48-hr LC50 5485.136

 : Green Algae 96-hr EC50 872.098

 : Fish ChV 1277.494

 : Daphnid ChV 329.594

 : Green Algae ChV 202.479

Note: * = asterisk designates: Chemical may not be soluble

 enough to measure this predicted effect.

Note: ! = exclamation designates: The toxicity value was determined from

 a predicted SAR using established acute-to-chronic ratios and ECOSAR

 regression techniques which are documented in the supporting Technical

 Reference Manual. When possible, this toxicity value should be

 considered in a weight of evidence approach.
84

Imides:

------

 For Fish and Daphnid Acute Toxicity Values: If the log Kow of the chemical

is greater than 5.0, or if the compound is solid and the LC50 exceeds the

water solubility by 10X, no effects at saturation are predicted for these

endpoints.

 For Green Algae Acute Toxicity Values: If the log Kow of the chemical is

greater than 6.4, or if the compound is solid and the EC50 exceeds the water

solubility by 10X, no effects at saturation are predicted for these endpoints.

 For All Chronic Toxicity Values: If the log Kow of the chemical is greater

than 8.0, or if the compound is solid and the ChV exceeds the water solubility

by 10X, no effects at saturation are predicted for these endpoints.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: 5.0 (LC50)

Maximum LogKow: 6.4 (EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Amides :

-------

No limitations known at this time.

ECOSAR v1.00 SAR Limitations:

----------------------------

Maximum LogKow: >8.5 (LC50)

Maximum LogKow: >8.0 (EC50,ChV)

Maximum Mol Wt: 1000

Baseline Toxicity SAR Limitations:

---------------------------------

Maximum LogKow: 5.0 (Fish 96-hr LC50; Daphnid LC50)

Maximum LogKow: 6.4 (Green Algae EC50)

Maximum LogKow: 8.0 (ChV)

Maximum Mol Wt: 1000

Ring-opened Chlorsulfuron

ASTER ECOTOXICITY PROFILE 

U.S. Environmental Protection Agency

Office of Research and Development

National Health and Environmental Effects Research Laboratory

Mid-Continent Ecology Division

Contact: Scientific Outreach Program

218-529-5225 or FAX 218-529-5003

Internet: ecotox.support@epa.gov

The ASTER (ASsessment Tools for the Evaluation of Risk) database integrates aquatic and 

terrestrial toxicity database information and quantitative structure activity relationships 
85

(QSARs) to assess the environmental risk of discrete chemicals. ASTER is designed to 

provide high quality data for discrete chemicals, when available in the ECOTOX database, 

and mechanistically-based QSAR estimates when data are lacking.

You should consult the original scientific paper to ensure an understanding of the context of 

the data retrieved from the ECOTOX database.

I. CHEMICAL IDENTIFICATION

Parameter Value

Name

CAS Number -1

SMILES C1=CC=CC(=C1Cl)S(NC(NC(NC(NCC)=O)=O)=O)(=O)=O

Formula C11CLH13N4O5S

II. ENVIRONMENTAL EXPOSURE ASSESSMENT

Parameter Value Source Reference

Molecular Weight (g/mole) 348.76 Calculated

Melting Point (C) Not available for this chemical

Boiling Point (C) 481.66 Calculated

Vapor Pressure (mm of Hg) 2.36E-12 Calculated

Ht Vaporization (cal/mole) 2.55E04 Calculated

Solubility in Water (mg/L) 652.72 Calculated

CLogP 0.70 CLogP 83337

KowWin 2.86** KowWin 83336

pKa Not available for this chemical

Adsorption Coef (log Koc) 2.89 Calculated

Henry's Constant (atmm**3/mole) 1.66E-15 Calculated

Log10 (Henry's Constant)(atmm**3/mole) -14.78 Calculated

Hydrolysis Half-life (days) Not available for this chemical

BioDegradation Data Linear Model Prediction : Does Not 

Biodegrade Fast

Non-Linear Model Prediction: Does 

Not Biodegrade Fast

Ultimate Biodegradation Timeframe: 

Months

Primary Biodegradation Timeframe: 

Weeks

MITI Linear Model Prediction : Not 

Readily Degradable

MITI Non-Linear Model Prediction: 

Not Readily Degradable

<BR< font>

BioWin 83338
86

Mackay Level 1 Environmental 

Partitioning @ 25C

Fugacity = 2.16E-15 Pa

0.00 % into air

5.17 % into soil

90.00 % into water

0.01 % into suspended solids

0.00 % into aquatic biota

4.82 % into sediment

** Denotes the LogP value used in calculations

III. ECOTOXICOLOGICAL HAZARD ASSESSMENT

Table 1. Geometric Means of all data passing the ASTER filter by Species Group

Habitat Species Effect Count Geo Mean Min Max

No Records Found

Table 2. Median Acute Data values

Habit

at

Taxon Gro

up

Name Endpoi

nt

Effe

ct

Measu

re

Medi

a

Dur (

d)

Exposu

re

Median C

onc

Sour

ce

Ref

No

A Fish Pimephales 

promelas LC50 MOR MORT FW 4 S 42049.29 ug/L

QSA

R 9003

A Fish Ictalurus 

punctatus LC50 MOR MORT FW 4 S 18141.68 

ug/L

QSA

R 9003

A Fish Daphnia 

magna

LC50 MOR MORT FW 4 S 23260.33 

ug/L

QSA

R 9003

A Fish Oncorhync

hus mykiss LC50 MOR MORT FW 4 S 17458.54 ug/L

QSA

R 9003

A Fish

Lepomis 

macrochiru

s

LC50 MOR MORT FW 4 S 33276.23 

ug/L

QSA

R 9003

Table 3. Median Chronic Data values

Habit

at

Taxon Gro

up

Name Endpoi

nt

Effe

ct

Measu

re

Medi

a

Dur (

d)

Exposu

re

Median Co

nc

Sourc

e

Ref N

o

A Fish

Pimephal

es 

promelas

MATC GRO GGRO FW 4 S 6941.73 

ug/L QSAR 9003

Table 4. Median Bioconcentration Data values

Habit

at

Taxon Gr

oup

Name Endpo

int

Effe

ct

Meas

ure

Med

ia

Dur (

d)

Expos

ure

Sit

e

Median C

onc

BCF Va

lue

Sour

ce

Ref

No

A Fish

Pimeph

ales 

promela

s

BCF AC

C RSDE FW 4 S W

O 72.34 QSA

R 7

Table 5. Additional Agency Benchmark Data
87

Habit

at

Taxon Gro

up

Nam

e

Endpoi

nt

Effec

t

Measur

e

Medi

a

Dur (d

)

Exposur

e

Median Co

nc

Sourc

e

Ref N

o

No Records Found

IV. ECOLOGICAL RISK CHARACTERIZATION

A. Environmental Exposure Assessment

Henry's Constant = 1.66E-15 atm-m**3/mole

Log10 (Henry's Constant) = -14.78 atm-m**3/mole

Lyman et al. 1982. would conclude that a chemical with these properties is non-volatile. See 

page 15-15.

The QSAR system does not yet model the hydrolysis of Urea derivatives like this.

B. Ecotoxicological Hazard Assessment

NONPOLAR NARCOSIS The acute mode of toxic action for this class of xenobiotics is 

generally attributed to narcosis (the toxicologically induced and reversible stages of neural 

disruption, i.e. general anesthesia). Intoxication via nonpolar narcosis is thought to be the 

minimal effect that can be elicited by a xenobiotic and the QSAR for nonpolar narcosis 

provides predictions of baseline acute toxicity [3261]. Chemicals that act via a more specific 

mode of action, or are metabolically activated, will generally be more toxic than what would 

be predicted by the nonpolar narcosis QSAR. The acute toxicity modeling component in 

ASTER assesses the structural characteristics of chemicals and evaluates whether or not an 

entered compound contains specific functional moieties (or moieties capable of being 

bioactivated) that are associated with more specific modes of toxic action. The nonpolar 

narcosis QSAR is invoked only if the structural characteristics of a chemical do not suggest a 

more specific mode of action.

When sufficient data is available from fathead minnow early life stage (ELS) tests (32-d 

exposures) completed at MED-Duluth, QSAR models have been developed to predict chronic 

values for either survival or growth, which ever is the most sensitive endpoint. A chronic 

value is defined as the geometric mean of the LOEC (lowest observable effect concentration) 

and the NOEC (no observable effect concentration). These models have been developed for 

groups of xenobiotics that have been classified based on their acute modes of toxic action. 

Empirical observations suggest that when a statistically robust ELS QSAR can be established 

and when 96-h LC50/32-d ELS chronic value ratios are within a factor of 20 it is reasonable 

to assume that adverse effects are elicited through the same mode of toxic action in both 4-

d and 32-d exposures. If during a chronic exposure a different mode of action is involved, or 

if metabolic activation is significant, the ratios between acute and chronic endpoint values 

for a group of xenobiotics are generally quite variable and typically exceed two orders of 

magnitude. In addition, the statistical strength of ELS QSARs in these instances are poor.

C. Other Information

Triazine Amine

08-Aug-12

ASTER ECOTOXICITY PROFILE 
88

U.S. Environmental Protection Agency

Office of Research and Development

National Health and Environmental Effects Research Laboratory

Mid-Continent Ecology Division

Contact: Scientific Outreach Program

218-529-5225 or FAX 218-529-5003

Internet: ecotox.support@epa.gov

The ASTER (ASsessment Tools for the Evaluation of Risk) database integrates aquatic and 

terrestrial toxicity database information and quantitative structure activity relationships 

(QSARs) to assess the environmental risk of discrete chemicals. ASTER is designed to 

provide high quality data for discrete chemicals, when available in the ECOTOX database, 

and mechanistically-based QSAR estimates when data are lacking.

You should consult the original scientific paper to ensure an understanding of the context of 

the data retrieved from the ECOTOX database.

I. CHEMICAL IDENTIFICATION

Parameter Value

Name

CAS Number -1

SMILES C1(=NC(=NC(=N1)C)N([H])[H])OC

Formula C5H6N4O

II. ENVIRONMENTAL EXPOSURE ASSESSMENT

Parameter Value Source Reference

Molecular Weight (g/mole) 138.13 Calculated

Melting Point (C) Not available for this chemical

Boiling Point (C) 211.10 Calculated

Vapor Pressure (mm of Hg) 0.21 Calculated

Ht Vaporization (cal/mole) 1.07E04 Calculated

Solubility in Water (mg/L) 2.40E04 Calculated

CLogP -1.10 CLogP 83337

KowWin 1.26** KowWin 83336

pKa Not available for this chemical

Adsorption Coef (log Koc) 2.02 Calculated

Henry's Constant (atmm**3/mole) 1.55E-06 Calculated

Log10 (Henry's Constant)(atmm**3/mole) -5.81 Calculated

Hydrolysis Half-life (days) Hydrolysis unlikely

BioDegradation Data Linear Model Prediction : 83338
89

Biodegrades Fast

Non-Linear Model Prediction: Does 

Not Biodegrade Fast

Ultimate Biodegradation Timeframe: 

Weeks-Months

Primary Biodegradation Timeframe: 

Days-Weeks

MITI Linear Model Prediction : Not 

Readily Degradable

MITI Non-Linear Model Prediction: 

Not Readily Degradable

<BR< font>

Mackay Level 1 Environmental 

Partitioning @ 25C

Fugacity = 2.13E-06 Pa

5.15 % into air

0.14 % into soil

94.59 % into water

0.00 % into suspended solids

0.00 % into aquatic biota

0.13 % into sediment

** Denotes the LogP value used in calculations

III. ECOTOXICOLOGICAL HAZARD ASSESSMENT

Table 1. Geometric Means of all data passing the ASTER filter by Species Group

Habitat Species Effect Count Geo Mean Min Max

No Records Found

Table 2. Median Acute Data values

Habit

at

Taxon Gro

up

Name Endpoi

nt

Effe

ct

Measu

re

Medi

a

Dur (

d)

Exposu

re

Median C

onc

Sour

ce

Ref

No

A Fish Pimephales 

promelas LC50 MOR MORT FW 4 S 508615.0

5 ug/L

QSA

R 9003

A Fish Ictalurus 

punctatus LC50 MOR MORT FW 4 S 218687.07 ug/L

QSA

R 9003

A Fish Daphnia 

magna

LC50 MOR MORT FW 4 S 236329.4

6 ug/L

QSA

R 9003

A Fish Oncorhync

hus mykiss LC50 MOR MORT FW 4 S 242121.52 ug/L

QSA

R 9003

A Fish

Lepomis 

macrochiru

s

LC50 MOR MORT FW 4 S 375895.4

8 ug/L

QSA

R 9003

Table 3. Median Chronic Data values

Habit

at

Taxon Gro

up

Name Endpoi

nt

Effe

ct

Measu

re

Medi

a

Dur (

d)

Exposu

re

Median Co

nc

Sourc

e

Ref N

o

A Fish

Pimephal

es 

promelas

MATC GRO GGRO FW 4 S 68049.41 

ug/L QSAR 9003
90

Table 4. Median Bioconcentration Data values

Habit

at

Taxon Gr

oup

Name Endpo

int

Effe

ct

Meas

ure

Med

ia

Dur (

d)

Expos

ure

Sit

e

Median C

onc

BCF Va

lue

Sour

ce

Ref

No

A Fish

Pimeph

ales 

promela

s

BCF AC

C RSDE FW 4 S W

O 3.94 QSA

R 7

Table 5. Additional Agency Benchmark Data

Habit

at

Taxon Gro

up

Nam

e

Endpoi

nt

Effec

t

Measur

e

Medi

a

Dur (d

)

Exposur

e

Median Co

nc

Sourc

e

Ref N

o

No Records Found

IV. ECOLOGICAL RISK CHARACTERIZATION

A. Environmental Exposure Assessment

Henry's Constant = 1.55E-06 atm-m**3/mole

Log10 (Henry's Constant) = -5.81 atm-m**3/mole

Lyman et al. 1982. would conclude that a chemical with these properties will volatilize 

slowly from open water. See page 15-15.

Hydrolysis is not likely to be an important transformation mechanism for this chemical.

B. Ecotoxicological Hazard Assessment

NONPOLAR NARCOSIS The acute mode of toxic action for this class of xenobiotics is 

generally attributed to narcosis (the toxicologically induced and reversible stages of neural 

disruption, i.e. general anesthesia). Intoxication via nonpolar narcosis is thought to be the 

minimal effect that can be elicited by a xenobiotic and the QSAR for nonpolar narcosis 

provides predictions of baseline acute toxicity [3261]. Chemicals that act via a more specific 

mode of action, or are metabolically activated, will generally be more toxic than what would 

be predicted by the nonpolar narcosis QSAR. The acute toxicity modeling component in 

ASTER assesses the structural characteristics of chemicals and evaluates whether or not an 

entered compound contains specific functional moieties (or moieties capable of being 

bioactivated) that are associated with more specific modes of toxic action. The nonpolar 

narcosis QSAR is invoked only if the structural characteristics of a chemical do not suggest a 

more specific mode of action.

Appendix C. Ecological Toxicity Summary for Aquatic and Terrestrial Organisms from 

Chlorsulfuron

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

Birds1

Acute 

(Dose-based)

Bobwhite Quail 

(Colinus 

virginianus)

LD50 >5,000 mg a.i./kg-bw Avian Acute

000352-63

(Acceptable)

Practically 

non-toxic

Sub-Acute Dietary

Mallard Duck

(Anas 

platyrhynchos)

LC50>5,000 mg a.i./kgdiet

Avian Dietary

000352-66 

(Acceptable)

--
91

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

Chronic

Mallard Duck NOAEC ≥961 mg a.i./kg-diet

LOAEC >961 mg a.i./kg-diet

Avian Reproduction

426340-02

(Acceptable)

--

Bobwhite Quail 

(Colinus 

virginianus)

NOAEC = 174 mg a.i./kgdiet

LOAEC = 961 mg a.i./kg-diet

Avian Reproduction 

426340-01

(Acceptable)

--

Mammals

Acute

Laboratory Rat 

(Rattus norvegicus)

LD50>5,500 mg a.i./kg-bw

Acute Mammal

000314-06

(Acceptable)

Practically 

Non-toxic

Chronic NOAEL = 100 mg/kg/day 

LOAEL = 500 mg/kg-diet

Chronic 

000860-03 

(Acceptable)

--

Insects

Acute (contact) Honey Bee 

(Apis mellifera L.) LD50>25 ug a.i./bee

48-Hour

421299-02

(Acceptable)

Practically 

Non-toxic

Freshwater fish2

Acute Rainbow Trout

(Oncorhynchus 

mykiss) 

LC50>300 mg a.i./L

96-Hour 

000352-58

(Acceptable)

Practically

Non-toxic

Chronic NOAEC (length) 

= 32 mg a.i./L

Early Life Stage

419764-05

(Acceptable)

--

Freshwater Invertebrates

Acute

Water Flea 

(Daphnia magna)

EC50>370 mg a.i./L 48-Hour

000352-62

(Acceptable)

Practically 

Non-toxic

Chronic NOAEC (reproduction) 

= 20 mg a.i./L

21-Day

419764-04 and 

419764-08

(Supplemental)

--

Estuarine/Marine Fish

Acute Sheepshead 

Minnow 

(Cyprindon 

varigatus)

LC50>980 mg a.i./L 96-Hour

419764-01 

(Acceptable)

Practically 

Non-toxic

Chronic NOAEC (length) = 980 mg 

a.i./L ---

Estuarine/Marine Invertebrates

Acute Eastern Oyster 

(Crassostrea 

virginica)

EC50=376 mg a.i./L

Static Acute

419764-03

(Supplemental)

Practically 

Non-toxic

EC50=385 mg a.i./L

Static Acute

423286-01

(Acceptable)

Practically 

Non-toxic

Acute Mysid (Mysidopsis 

bahia) LC50>89 mg a.i./L

96-Hour

419764-02

(Acceptable)

Slightly toxic

Terrestrial Plants

Monocot Onion

(Allium cepa)

EC25 (dry wt) = 

3 x 10-4 lb a.i./A

----

NOAEC (dry wt) = 

4.5 x 10-5 lb a.i./A

Seedling Emergence

463618-01

(Supplemental) ---
92

Exposure Scenario Species

Acute Toxicity

--

Chronic Toxicity

Citation

MRID

Acute Toxicity 

Classification

EC25 (dry wt) = 

2.2 x 10-5 lb a.i./A

----

EC05 (shoot height) = 

2.6 x 10-6 lbs a.i./A

Vegetative Vigor

463268-01

(Supplemental) ---

Dicot

Pea 

(Pisum sativum)

EC25= 2.2 x 10-5 lb a.i./A

----

NOAEC = 1.8 x 10-4 lb a.i./A

Seedling Emergence

463618-01

(Supplemental)

---

Rape

(Brassica rapa)

EC25 (dry wt) = 

1.0 x 10-5 lb a.i./A

EC05 (shoot height) = 

8.0 x 10-7 lb a.i./A

Vegetative Vigor

46578942 

(Supplemental)

---

Aquatic Plants

Aquatic vascular 

Plants

Duckweed 

(Lemna gibba)

EC50 (dry wt) =

3.5 x 10-4 mg a.i./L

-------

NOAEC (frond no. and dry 

wt) =

2.4 x 10-4 mg a.i./L

14-Day Study

458329-01

(Supplemental)

---

Non-Vascular 

Aquatic Plants

Green Algae 

(Selenastrum 

capricornutum)

EC50 (cell density) =

0.05 mg a.i./L

-------

NOAEC (cell density) = 

0.0094 mg a.i./L

120-Hour

421868-01

(Supplemental)

---

Freshwater Algae 

(Anabaena flosaquae)

EC50= (biomass) 0.61 mg 

a.i./L

------

NOAEC (biomass and cell 

density) =0.24 mg a.i./L

120-Hour

458329-03

(Acceptable)

---

Algae (Skeletonema 

costatum)

EC50 (cell density, biomass 

and growth rate) >126 mg 

a.i./L

------

NOAEC (cell density, 

biomass and growth rate) = 

126 mg a.i./L

120-Hour

458329-02

(Acceptable)

---

Freshwater Algae 

(Navicula 

pelliculosa)

EC50 (cell density, biomass 

and growth rate) >126 mg 

a.i./L

------

NOAEC (cell density, 

biomass and growth rate) = 

126 mg a.i./L

120-Hour

458329-04

(Acceptable)

---
93

Appendix D. Results from Screening Imbibition Program (SIP) and the Screening Tool for 

Inhalation Risk Assessment (STIR)

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

upper bound estimate of exposure using chlorsulfuron’s highest water solubility (3,180,000 

mg/L, pH 7 at 25oC, MRID 42454104), the most sensitive acute and chronic avian toxicity 

endpoints (Bobwhite Quail with LD50 >5000 mg/kg-bw and NOAEC = 174 mg/kg-diet, 

respectively) and the most sensitive acute and chronic mammalian toxicity endpoints (Rat LD50

>5000 mg/kg-bw and NOAEL = 5 mg/kg-bw, respectively). Based on the output, exposure 

through drinking water alone results in potential acute and chronic risk to small birds and 

potential chronic risk to small mammals. Although due to the use of the non-definitive acute 

values where no mortality was observed at those reported levels and the very high water 

solubility, the potential for acute risk is expected to be quite conservative. Results from SIP are 

shown below.

Inhalation is another potential exposure route for terrestrial vertebrates. Based on the vapor 

pressure of chlorsulfuron’s physical-chemicl properties, it is nonvolatile from dry soil and water 

and is predictd to be rapidly lost from moist soil. However, because it is an anion, it is expected 

that loss from moist soil may be minimal and it was not rapidly lost from moist soils in 

laboratory studies. Therefore, risk from inhalation is not expected. The 4-hr LC50 inhalation 

study using rats was greater than 5.9 mg/L (MRID 00086825). The STIR model (Screening Tool 

for Inhalation Risk) was used to evaluate inhalation risk to birds. The non-definitive acute oral 

values for both birds and mammals were used in the model. Based on STIR, risk to birds from 

inhalation alone is not expected. Results from STIR are shown below.
94

SIP Version 1.0. August, 19, 2010
95

Results From STIR Version 1.0, November 23, 2010
96

Appendix E. Example T-Rex Input and Output for Chlorsulfuron.

 

T-Rex can be found at: http://www.epa.gov/oppefed1/models/terrestrial/trex_usersguide.htm 

Summary of Risk Quotient Calculations Based on Upper Bound Kenaga EECs

Table X. Upper Bound Kenaga, Acute Avian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted

LD50

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

20 3602.15 33.31 0.01 15.27 0.00 18.74 0.01 2.08 0.00 0.46 0.00

100 4585.71 19.00 0.00 8.71 0.00 10.69 0.00 1.19 0.00 0.26 0.00

1000 6477.49 8.50 0.00 3.90 0.00 4.78 0.00 0.53 0.00 0.12 0.00

Table X. Upper Bound Kenaga, Subacute Avian Dietary Based Risk Quotients

LC50

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

EEC RQ EEC RQ EEC RQ EEC RQ

0 29.25 ##### 13.41 ##### 16.45 #DIV/0! 1.83 #####

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Avian Dietary Based Risk Quotients

NOAEC 

(ppm)

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

EEC RQ EEC RQ EEC RQ EEC RQ

174 29.25 0.17 13.41 0.08 16.45 0.09 1.83 0.01

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Acute Mammalian Dose-Based Risk Quotients 

Size Adjusted EECs and RQs
97

Class

(grams)

LD50

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 12088.07 27.89 0.00 12.78 0.00 15.69 0.00 1.74 0.00 0.39 0.00

35 9780.54 19.27 0.00 8.83 0.00 10.84 0.00 1.20 0.00 0.27 0.00

1000 4230.38 4.47 0.00 2.05 0.00 2.51 0.00 0.28 0.00 0.06 0.00

Table X. Upper Bound Kenaga, Acute Mammalian Dietary Based Risk 

Quotients

LC50 

(ppm)

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

EEC RQ EEC RQ EEC RQ EEC RQ

0 29.25 ##### 13.41 ##### 16.45 #DIV/0! 1.83 #####

Size class not used for dietary risk quotients

Table X. Upper Bound Kenaga, Chronic Mammalian Dietary Based Risk 

Quotients

NOAEC 

(ppm)

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

EEC RQ EEC RQ EEC RQ EEC RQ

100 29.25 0.29 13.41 0.13 16.45 0.16 1.83 0.02

Size class not used for dietary risk quotients 

Table X. Upper Bound Kenaga, Chronic Mammalian Dose-Based Risk Quotients

Size 

Class

(grams)

Adjusted 

NOAEL

EECs and RQs

Short Grass Tall Grass

Broadleaf 

Plants/

Small Insects

Fruits/Pods/

Seeds/

Large Insects

Granivore

EEC RQ EEC RQ EEC RQ EEC RQ EEC RQ

15 10.99 27.89 2.54 12.78 1.16 15.69 1.43 1.74 0.16 0.39 0.04

35 8.89 19.27 2.17 8.83 0.99 10.84 1.22 1.20 0.14 0.27 0.03

1000 3.85 4.47 1.16 2.05 0.53 2.51 0.65 0.28 0.07 0.06 0.02
98

Appendix F. Example Terrplant (v. 1.2.2) Input and Output for Chlorsulfuron

 

TerrPlant v. 1.2.2

Green values signify user inputs (Tables 1, 2 and 4). 

Input and output guidance is in popups indicated by red arrows.

Table 1. Chemical Identity.

Chemical Name Chlorsulfuron

PC code 118601

Use Ornamental Turf

Application Method Ground

Application Form Spray 

Solubility in Water 

(ppm) 587

Table 2. Input parameters used to derive EECs.

Input Parameter Symbol Value Units

Application Rate A 0.121875 lb ai/A

Incorporation I 1 none

Runoff Fraction R 0.05 none

Drift Fraction D 0.01 none

Table 3. EECs for Chlorsulfuron. Units in lb ai/A.

Description Equation EEC

Runoff to dry areas (A/I)*R 0.00609375

Runoff to semi-aquatic areas (A/I)*R*10 0.0609375

Spray drift A*D 0.00121875

Total for dry areas ((A/I)*R)+(A*D) 0.0073125

Total for semi-aquatic areas ((A/I)*R*10)+(A*D) 0.06215625

Table 4. Plant survival and growth data used for RQ derivation. Units are in lb ai/A.

Seedling Emergence Vegetative Vigor

Plant type EC25 NOAEC EC25 NOAEC 

Monocot 0.0003 0.000045 0.000022 0.0000026

Dicot 0.000022 0.00018 0.00001 0.0000008

Table 5. RQ values for plants in dry and semi-aquatic areas exposed to Chlorsulfuron through runoff 

and/or spray drift.*

Plant Type Listed Status Dry Semi-Aquatic Spray Drift

Monocot non-listed 24.38 207.19 55.40

Monocot listed 162.50 1381.25 468.75

Dicot non-listed 332.39 2825.28 121.88

Dicot listed 40.63 345.31 1523.44

*If RQ > 1.0, the LOC is exceeded, resulting in potential for risk to that plant group.
99

Appendix G. Reference List for OPPTS/OCSPP Fate Guidelines

The Office of Prevention, Pesticides, and Toxic Substances (OPPTS) became the Office of 

Chemical Safety and Pollution Prevention (OCSPP) in 2011. Some guidelines have not been 

updated since the name change and the titles still use OPPTS. Others have been updated and 

reference OCSPP.

OPPTS or OCSPP

Guideline

Citation

Hydrolysis

835.2120

(161-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2120 Hydrolysis. E. 

712-C-08-012. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aqueous Photolysis 

835.2240

(161-2)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2240 

Photodegradation in Water. E. 712-C-08-013. October 2008. Office of Prevention, Pesticides, and 

Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Soil Photolysis

835.2410

(161-3)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.2410 

Photodegradation in Soil. E. 712-C-08-015. October 2008. Office of Prevention, Pesticides, and 

Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aerobic Soil 

Metabolism 

835.4100

(162-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.4100 Aerobic Soil 

Metabolism; OPPTS 835.4200 Anaerobic Soil Metabolism. EPA712-C-08-016 & E. 712-C-08-017. 

October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States Environmental 

Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 17, 

2012).

Anaerobic Soil 

Metabolism

835.4200

(162-2)

Aerobic Aquatic 

Metabolism 

835.4300

(162-4)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.4300 Aerobic Aquatic 

Metabolism; OPPTS 835.4400 Anaerobic Aquatic Metabolism. EPA 712-C-08-018 & E. 712-C-08-

019. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 17, 

2012). Anaerobic Aquatic 

Metabolism 

835.4400

(162-3)

Sorption coefficients

835.1230

(163-1)

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1230 

Adsorption/Desorption (Batch Equilibrium). E. 712-C-08-009. October 2008. Office or Prevention, 

Pesticides, and Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Leaching and Aged 

Column Leaching 

835.1240

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1240 Leaching Studies. 

E. 712-C-08-010. October 2008. Office of Prevention, Pesticides, and Toxic Substances. United 

States Environmental Protection Agency. Available at 

http://www.regulations.gov/#!documentDetail;D=EPA-HQ-OPPT-2009-0152-0007 (Accessed May 

5, 2012).
100

OPPTS or OCSPP

Guideline

Citation

Terrestrial Field 

Dissipation

835.6100

USEPA. 2008. Fate, Transport, and Transformation Guidelines. OPPTS 835.1230 

Adsorption/Desorption (Batch Equilibrium). E. 712-C-08-009. October 2008. Office or Prevention, 

Pesticides, and Toxic Substances. United States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 5, 

2012).

Aquatic Field 

Dissipation

835.6200

USEPA. 2008. Fate, Transport, and Transformation Test Guidelines. OPPTS Aquatic (Sediment) 

Field Dissipation. EPA 712-C-08-021. October 2008. Office of Prevention, Pesticides, and Toxic 

Substances. United States Environmental Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series835.htm (Accessed May 15, 

2012).

Bioconcentration 

Factor

850.1730

USEPA. 1996. Ecological Effects Test Guidelines. OPPTS 850.1730 Fish BCF. E. 712-C-96-129. 

April 1996. Environmental Fate and Effects Division. Office of Pesticide Programs. United States 

Environmental Protection Agency. Available at 

http://www.epa.gov/opptsmnt/pubs/frs/publications/OPPTS_Harmonized/850_Ecological_Effects_T

est_Guidelines/Drafts/850-1730.pdf (Accessed May 14, 2012).

Environmental 

Chemistry Method

850.6100

USEPA. 2012. Ecological Effects Test Guidelines. OCSPP 850.6100: Environmental Chemistry 

Methods. E. 712-C-001. January 2012. Office of Chemical Safety and Pollution Prevention. United 

States Environmental Protection Agency. Available at 

http://www.epa.gov/ocspp/pubs/frs/publications/Test_Guidelines/series850.htm (Accessed August 

10, 2012).
101

Appendix H. Identification of Transformation Products and Listing of the Maximum 

Amounts Observed in Fate Studies

Table H1. Summary of maximum amount of transformation products observed in fate 

studies.

Chemical Study Type MRID Maximum %AR (day)a Final %AR (study length)a

Chlorsulfuron

Hydrolysis 42156701

39 (31 days), pH 5, ph 

40 (31 days), pH 5, tri

99 (31 days), pH 7, ph

97 (31 days), pH 7, tri

96 (31 days), pH 9, ph

98 (31 days, pH 9, tri

Aqueous 

photolysis 42156702

97 (31 days) light, pH 7, ph

99 (31 days) dark, pH 7, ph

98 (31 days), light, pH 7, tri

97 (31 days), dark, pH 7, tri

Soil photolysis 41721001 

42156703 75.7 (73.6 days) tri

Aerobic Soil 00035275

7.4 (180 days), 1 mg/kg, ph

6.7 (180 days, 0.1 mg/kg, ph

Anaerobic 

Aquatic 42156704

54 (365 days), PA, tri

75 (70 days), PA, phe

50 (56 days), Canada, phe

82 (35 days), NE, phe

66 (28 days), IL, phe

Odesmethylchlorsulfuron 

(ODMC)

Hydrolysis 42156701

13 (21 days), pH 5, ph

14 (21 days), pH 5, tri

ND pH 7, ph

1 (31 days), pH 7, tri

1 (31 days), pH 9, ph

2 (31 days, pH 9, tri

10 (31 days), pH 5, ph 

12 (31 days), pH 5, tri

ND (31 days), pH 7, ph

1 (31 days), pH 7, tri

1 (31 days), pH 9, ph

2 (31 days, pH 9, tri

Aqueous 

photolysis 42156702

1.4 (31 days), pH 7 light, ph

0.5 (31 days), pH 7 dark, ph

0.9 (21 days), light, pH 7, tri

1.1 (31 days), dark, pH 7, tri

1.4 (31 days), pH 7 light, ph

0.5 (31 days), pH 7 dark, ph

0.9 (21 days), light, pH 7, tri

1.1 (31 days), dark, pH 7, tri

Soil photolysis 41721001 

42156703 2.8 (74 days), tri 2.8 (74 days), tri

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic1 42156704

31 (365 days), PA, tri

11 (70 days), PA, phe

18 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

31 (365 days), PA, tri

11(70 days), PA, phe

18 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

Ring-opened 

chlorsulufuron

Hydrolysis 42156701

16 (31 days), pH 5, ph 

18 (31 days), pH 5, tri

ND (31 days), pH 7, ph

ND (31 days), pH 7, tri

ND (31 days), pH 9, ph

ND (31 days, pH 9, tri

16 (31 days), pH 5, ph 

18 (31 days), pH 5, tri

ND (31 days), pH 7, ph

ND (31 days), pH 7, tri

ND (31 days), pH 9, ph

ND (31 days, pH 9, tri
102

Chemical Study Type MRID Maximum %AR (day)a Final %AR (study length)a

Aqueous 

photolysis 42156702 NR pH 7 NR pH 7

Soil photolysis 41721001 

42156703 NR NR

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic1 42156704

31 (365 days), PA, tri

11 (70 days), PA, phe

18 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

31 (365 days), PA, tri

11(70 days), PA, phe

18 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

2-

chlorobenzenesulfonami

de (CSM)

Hydrolysis 42156701

33 (31 days), pH 5, ph 

NA (31 days), pH 5, tri

1 (31 days), pH 7, ph

NA (31 days), pH 7, tri

2 (31 days), pH 9, ph

NA (31 days, pH 9, tri

33 (31 days), pH 5, ph 

NA(31 days), pH 5, tri

1 (31 days), pH 7, ph

NA (31 days), pH 7, tri

2 (31 days), pH 9, ph

NA(31 days, pH 9, tri

Aqueous 

photolysis 42156702

1.7 (31 days), pH 7 light, ph

1.0 (21 days), pH 7 dark, ph

NA, pH 7, tri

1.7(31 days), pH, 7 light, ph

0.8 (31 days), pH 7 dark, ph

NA, pH 7, tri

Soil photolysis 41721001 

42156703 NR NR

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704

NR (365 days), PA, tri

14 (70 days), PA, phe

11 (56 days), Canada, phe

17 (21 days), NE, phe

13 (28 days), IL, phe

NR (365 days), PA, tri

14(70 days), PA, phe

11 (56 days), Canada, phe

3 (35 days), NE, phe

13 (28 days), IL, phe

Triazine Amine (TA)

Hydrolysis 42156701

NA (31 days), pH 5, ph 

17 (31 days), pH 5, triazine

NA(31 days), pH 7, ph

1 (31 days), pH 7, triazine

NA (31 days), pH 9, ph

1 (31 days, pH 9, triazine

NA (31 days), pH 5, ph 

17(31 days), pH 5, triazine

NA (31 days), pH 7, ph

1 (31 days), pH 7, triazine

NA (31 days), pH 9, ph

1 (31 days, pH 9, triazine

Aqueous 

photolysis 42156702 NR pH 7 NR pH 7

Soil photolysis 41721001 

42156703 5.5 (74 days), tri 5.5 (74 days), tri

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704

21 (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

21 (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

2-chlorosulfonylurea 

(CPSU) Anaerobic 

Aquatic 42156704

NA (365 days), PA, tri

3.1 (7 days), PA, phe

14 (56 days), Canada, phe

12 (35 days), NE, phe

9.1 (28 days), IL, phe

NA(365 days), PA, tri

2.1 (70 days), PA, phe

14 (56 days), Canada, phe

12 (35 days), NE, phe

9.1 (28 days), IL, phe
103

Chemical Study Type MRID Maximum %AR (day)a Final %AR (study length)a

Dihydroxy Triazine 

(DT)

Hydrolysis 42156701

NA (31 days), pH 5, ph 

9 (31 days), pH 5, triazine

NA (31 days), pH 7, ph

ND (31 days), pH 7, triazine

NA (31 days), pH 9, ph

ND (31 days, pH 9, triazine

NA (31 days), pH 5, ph 

9 (31 days), pH 5, triazine

NA (31 days), pH 7, ph

ND(31 days), pH 7, triazine

NA (31 days), pH 9, ph

ND (31 days, pH 9, triazine

Soil photolysis 41721001 

42156703 1.2 (74 days), tri 1.2 (74 days), tri

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704

NA (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

NA (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

O-desmethyl triazine 

Amine (ODMTA)

Structure not provided

Anaerobic 

Aquatic 42156704

<0.1 (365 days), PA, tri

<0.1 (70 days), PA, phe

<0.1 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

<0.1 (365 days), PA, tri

<0.1 (70 days), PA, phe

<0.1 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

Triazine Urea (TU)

Hydrolysis 42156701 NA NA

Aqueous 

photolysis 42156702 NR pH 7 NR pH 7

Soil photolysis 41721001 

42156703 7.6 (74 days), tri 7.6 (74 days), tri

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704

NR (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

NR (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

Hydroxy Triazine 

Amine (OHTA) Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704

NR (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

NR (365 days), PA, tri

NA (70 days), PA, phe

NA (56 days), Canada, phe

NA (35 days), NE, phe

NA (28 days), IL, phe

Hydroxy Chlorsulfuron 

(OHCSF)

Hydrolysis 42156701 NA NA

Aqueous 

photolysis 42156702 NA NA

Soil photolysis 41721001 

42156703 NA NA
104

Chemical Study Type MRID Maximum %AR (day)a Final %AR (study length)a

Aerobic Soil 00035275 NA NA

Anaerobic 

Aquatic 42156704 NA NA

5-

hydroxychlorosulfanami

de (OHCSM)

Anaerobic 

Aquatic 42156704

NR (365 days), PA, tri

<0.1 (70 days), PA, phe

<0.1 (56 days), Canada, phe

<0.1 (21 days), NE, phe

<0.1 (28 days), IL, phe

NR (365 days), PA, tri

<0.1 (70 days), PA, phe

<0.1 (56 days), Canada, phe

<0.1 (35 days), NE, phe

<0.1 (28 days), IL, phe

Others/ Individual 

Unknowns

Hydrolysis 42156701 ≤2 ≤2 (31 days)

Aqueous 

photolysis 42156702 NR pH 7 NR pH 7

Soil photolysis 41721001 

42156703 1.7 (53 days), tri 1.6 (74 days), tri

Aerobic Soil 00035275 52.9 (180 days), 0.1 mg/kg, ph

60.4 (180 days, 1.0 mg/kg, ph

52.9 (180 days), 0.1 mg/kg, 

ph

60.4 (180 days, 1.0 mg/kg, 

ph

Unextracted residues

Soil photolysis 41721001

42156703

7.2 (18 days), light, tri

8.8 (7 days), dark, tri

9.7 (77 days), light, ph

6.2 (31 days), dark, ph

3.8 (74 days), light, tri

3.5 (31 days, dark, tri

9.7 (77 days), light, ph

6.2 (31 days), dark, ph

Aerobic Soil 00035275 9 (120 days), 0.1 mg/kg, ph

7 (120 days), 1 mg/kg, ph

5 (120 days), 0.1 mg/kg, ph

5 (120 days), 1 mg/kg, ph

Anaerobic 

Aquatic 42156704

4 (365 days), PA, tri

2 (28 days), PA, phe

14 (56 days), Canada, phe

14 (21 days), NE, phe

13 (28 days), IL, phe

4 (365 days), PA, tri

1 (70 days), PA, phe

14 (56 days), Canada, phe

10 (35 days), NE, phe

13 (28 days), IL, phe

CO2

Soil photolysis 41721001 

42156703 

<0.9 (74 days), light, tri 

<0.5 (31 days), dark, tri 

8.0 (31 days), light, ph 

<1 (31 days), dark, ph 

<0.9 (74 days), light, tri 

<0.5 (31 days), dark, tri 

8.0 (31 days), light, ph 

<1 (31 days), dark, ph 

Aerobic Soil 00035275 5 (180 days), 0.1 mg/kg, ph

5 (180 days), 1 mg/kg, ph

5 (120 days), 0.1 mg/kg, ph

5 (120 days), 1 mg/kg, ph

Total Volatiles

Soil photolysis 41721001

42156703

<2.5 (74 days), light, tri

<2.1 (74 days), dark, tri

8 (31 days), light, ph

<3.3 (31 days), dark, ph

<2.5 (74 days), light, tri

<2.1 (74 days), dark, tri

8 (31 days), light, ph

<3.3 (31 days), dark, ph

ND=not detected; NA=not analyzed; NR=not reported in DER; ph=phenyl ring radiolabed; tri=triazine ring 

radiolabeled

1 The study reported total amount of polar compounds and indicated that the polar compounds were o-desmethyl 

chlorsulfuron or ring-opened chlorsulfuron. The total amount reported as polar compounds were reported for odesmethyl chlorsulfuron and ring-opened chlorsulfuron.
105

Table H2. Name, SMILES Code, Molecular Weight, and Structure of Chlorsulfuron and 

its Transformation Products2

Chemical Structure

Common Name: Chlorsulfuron (CSF)

IUPAC Name: 2-chloro-N

1-(2-chlorophenylsulfonyl)-3-(4-methoxy-6-methyl1,3,5-triazin-2-yl)urea

CAS name: 2-chloro-N-[[(4-methoxy-6-methyl1,3,5-triazin-2-

yl)amino]carbonyl]benzenesulfonamide

Other names: DPX-4189; IN-W4189

SMILES:

Clc1ccccc1S(=O)(=O)NC(=O)Nc2nc(nc(OC)n2)C

MW=357.77

Common Name: 5-hydroxychlorsulfuron (OHCSF)

Other Names: 2-chloro-5-hydroxy-N-[(4-methoxy6-methyl-1,3,5-triazin-2-yl)aminocarbonyl] 

benzenesulfonamide; IN-M6957

SMILES: 

ClC1=C(C=C(C=C1)O)S(=O)(=O)NC(=O)NC2=N

C(=NC(=N2)C)OC

MW=373.77

Log KOW=1.70 (estimated)

Common Name: O-desmethylchlorsulfuron 

(ODMC)

Other Names: 2-chloro-N-[[(4-hydroxy-6-methyl1,3,5-triazine-2-yl)-

amino)carbonyl]benzenesulfanamide

SMILES:

ClC1=C(C=CC=C1)S(=O)(=O)NC(=O)NC2=NC(=

NC(=N2)C)O[H]

MW=343.75

Log KOW=1.20 (estimated)

Common Name: Ring-opened chlorsulfuron (ROC)

Other Names: 1-(2-chlorophenylsulfonyl)-7-

acetyltriuret;

2-chloro-N-[[[[[[(2-

oxethyl)amino]carbonyl]amino]carbonyl]-

amino]carbonyl]benzenesulfanamide; IN-JJ998

SMILES:

C1=CC=CC(=C1Cl)S(NC(NC(NC(NCC)=O)=O)=

O)(=O)=O

MW=348.76

Log KOW=2.86 (estimated)
106

Common Name: 2-chlorophenylsulfonylurea 

(CPSU)

Other Names: 2-chloro-N-

(aminocarbonyl)benzenesulfanamide

SMILES: C1=CC=CC(=C1Cl)S(NON)(=O)=O

MW=222.65

Log KOW= -1.74 (estimated)

Common Name: Chlorosulfonamide (CSM)

Other names: 2-chlorobenzenesulfanamide; 

INA4097

CAS#: 6961-82-6

SMILES:

C1=CC=CC(=C1Cl)S(N([H])[H])(=O)=O

MW=191.63

Log KOW=0.74 (experimental)

Common Name: 5-hydroxychlorosulfanamide 

(OHCSM)

Other names: 2-chloro-5-

hydroxybenzenesulfanamide; INA5760

SMILES:

C1=CC(=CC(=C1Cl)S(N([H])[H])(=O)=O)O

MW=207.63

Log KOW=0.53 (estimated)

Common Name: Triazine amine (TA)

Other Names: 2-amino-4-methoxy-6-methyl-1,3,5-

triazine; INA40981

CAS #: 1668-54-8

SMILES: C1(=NC(=NC(=N1)C)N([H])[H])OC

MW=140.15

Log KOW=1.26 (estimated)

Common Name: Hydroxyy Triazine Amine (OH 

TA)

Other Names: 4-hydroxy-6-methyl-1,3,5-triazine2-amine; IN-B5528

CAS RN: 4719-11-3

SMILES: C1(=NC(=NC(=N1)C)N([H])[H])O

MW=126.12

Log KOW=0.21 (estimated)
107

Common Name: Dihydroxy Triazine (DT)

Other Names: 2,4-dihydroxy-6-methyl-1,3,5-

triazine

SMILES: C1(=NC(=NC(=N1)O[H])C)O[H]

MW=127.10

Log KOW=0.89 (estimated)

Common Name: Triazie Urea (TU)

Other Names: INV71603

SMILES: C1(=NC(=NC(=N1)OC)NC(N)=O)C

MW=183.17

Log KOW=0.89 (estimated)

O-desmethyltriazine amine (ODMTA) This was reportedly looked for in the anaerobic aquatic 

metabolism study (MRID 42156704); however, a 

structure and formal name was not provided. From the

name, it implies that it will be a structure similar to 

triazine amine with a missing methyl group.

Common Name: Acetylbiuret

Other Names: 1-acetylbiuret

CAS Number: 591-38-8

SMILES: C(N)(NC(NC(C)=O)=O)=O

MW=145.12

Log KOW= -0.43 1 This is a transformation product for chlorsulfuron, thifensulfuron methyl, tribenuron methyl, and metsulfuron 

methyl.

2 Molecular weight (MW) and log KOW were obtained from EPIWEB version 4.1.

3 This is a transformation product for chlorsulfuron and thifensulfuron-methyl.
108

Appendix I. Justification of the Identified Residues of Concern

The identified transformation products in environmental fate studies include ring-opened 

chlorsulfuron, o-desmethylchlorsulfuron, 2-chlorophenylsulfonylurea, chlorosulfonamide, 

triazine amine, hydroxy triazine amine, triazine urea, and dihydroxy triazine. All of these 

degradates are assumed to have the potential to occur in the natural environment and to have 

some potential for exposure. While hydroxychlorsulfuron, o-desmethyl triazine amine, hydroxyl 

chlorosulfonamide, and acetylbiuret are hypothesized degradation products, they were not 

observed in environmental fate studies; therefore, the likelihood of exposure to these degradates 

is assumed to be minimal. Appendix H provides structure, identity, and fate information on the 

transformation products. Incomplete fate data are available and other transformation products or 

higher percentages of transformation products could be observed in fate studies submitted in the 

future. Aerobic soil and aerobic aquatic metabolism studies are not available and are particularly 

important studies in understanding the environmental fate and transformation products that are 

likely to be observed in the natural environment. Toxicity data on chlorsulfuron degradation 

products have not been submitted to EFED; however, data are available from other sources. 

These data were used to prioritize the residues of concern for ecological risk assessment. As 

these prioritizations were made based on unreviewed data, these determinations may be revisited 

when data are fully reviewed. It is recommended that these data be submitted to EFED to 

support the reregistration of chlorsulfuron and to fully support determinations on the potential 

residues of concern for chlorsulfuron.

Residues of Concern for Drinking Water Consumed by Humans

The most recent drinking water assessment completed for chlorsulfuron was in support of the 

TRED and was completed in 2002 (Shanaman, 2002, D266073). A Tier 1 risk assessment was 

completed. The only residue considered in the assessment was the parent chlorsulfuron. In 1995 

the Health Effect Division (HED) Metabolism Committee Meeting (MARC) considered the 

residues of concern for residues for dietary items (e.g., in plants and commodities) (Abbots, 

1995a, 1995b). The committee determined that the residue to be regulated in plants and animal 

commodities was parent chlorsulfuron only. It is anticipated that the residues of concern for 

human health drinking water will be revisited as new fate data that could influence the decision 

on the potential residues of concern for human health drinking water become available. 

Sulfonylureas

O-desmethyl chlorsulfuron, ring-opened chlorsulfuron, and 2-chlorophenylsulfonylureas are the 

transformation products that retain the sulfonylurea bridge of parent chlorsulfuron (see Figure 

I1). O-desmethyl chlorsulfuron was detected at maxima of up to 31%, and was a major 

degradate in the hydrolysis and anaerobic aquatic metabolism study. Ring-opened chlorsulfuron 

was found at a maximum of 18% in the hydrolysis study. The metabolite 2-chlorosulfonylurea 

was found at a maximum of 12% in the anaerobic aquatic metabolism study. The odesmethylchlorsulfuron, ring-opened chlorsulfuron, and 2-chlorophenylsulfonylurea are present 

at high enough amounts in laboratory studies that they may be assumed to be found in the natural 

environment, and to potentially result in exposure. As o-desmethyl chlorsulfuron, ring-opened 

chlorsulfuron, and 2-chlorophenylsulfonylurea are sulfonylureas, they are assumed to be a 
109

residue of concern, and therefore a total toxic residue (TTR) approach will be used for evaluating 

exposure and risk for all taxa. In the absence of toxicity data on these three transformation 

products, their toxicities will be assumed to be similar to that of the parent. 

Definitive and measured toxicity data for o-desmethyl chlorsulfuron are available for green 

algae that suggest that o-desmethyl chlorsulfuron is much less toxic to aquatic plants than is 

chlorsulfuron (chlorsulfuron algae 72-hr EC50 was 0.05 mg/L and the o-desmethyl chlorsulfuron 

72-hr EC50 for green algae was 26.4 mg/L). Given that the only difference in structure between 

chlorsulfuron and o-desmethyl chlorsulfuron is the presence of a methyl group in place of a 

hydrogen in the former, not enough data across species are available to determine that odesmethyl chlorsulfuron is not a residue of concern for plants. Additionally, the chronic 

endpoints for fish suggest that the assumption of similar toxicity is appropriate for o-desmethyl 

chlorsulfuron. Chronic flow through studies are expected to only reflect exposure to parent 

chlorsulfuron. Depending on the hydrolysis and aerobic aquatic metabolism half-life, degradates 

may occur in chronic static studies (especially aquatic plant studies). The duration of the aquatic 

plant studies is 7-days for vascular plants and 96-hours for algal studies. No aerobic aquatic 

metabolism data are available for chlorsulfuron and it is stable to hydrolysis at pH 7 and 9. 

Therefore, there is not enough data to suggest that there was significant exposure to degradates in 

aquatic plant studies.

ECOSAR version 1.0 was also used to estimate the toxicity of transformation products (Table 

I1). ECOSAR is used to prioritize the need for additional data on degradates, but is not used in 

place of toxicity data or to calculate risk quotients. Based on ECOSAR analysis, ring-opened 

chlorsulfuron was shown to be a potential residue of concern for chronic toxicity to aquatic 

vertebrates and invertebrates, as predicted chronic endpoints were much lower than those for 

chlorsulfuron (20,000 – 32,000 μg/L for the parent and 5.6 to 94 μg/L for ring-opened 

chlorsulfuron). However, this prediction is based on very limited data, and given the weight of 

evidence is not sufficient to justify requiring additional data. Additionally, predicted acute 

endpoints for ring-opened chlorsulfuron were lower than those measured for the parent. These 

are discussed in more detail in the next paragraphs.

Data on the amide chemical class was used to estimate the sensitive toxicity endpoints. 

ECOSAR estimated the chronic endpoint of ring-opened chlorsulfuron for fish and the amide 

chemical class based on a single measured toxicity endpoint. The fish chronic toxicity endpoint 

used for the chemical class is for 4-nitrobenzamide and the endpoint is 1.74 mg/L. ECOSAR 

used an acute to chronic ratio approach for the amide class to estimate the chronic toxicity 

endpoint for daphnid for ring-opened chlorsulfuron. Based on the limited information used to 

predict the chronic toxicity of this class of compounds, there is a high level of uncertainty with 

this predicted endpoint. Based on the maximum amount observed of ring-opened chlorsulfuron 

as a fraction of the parent was at 31% in an anaerobic aquatic metabolism study and the highest 

EEC previously reported for chlorsulfuron of 9.5 μg/L (9.5 x 0.31 = 3 μg/L), concentrations of 

ring-opened chlorsulfuron could reach concentrations in the range of the predicted toxicity 

endpoints for chlorsulfuron; however the concentrations would be much lower than the one 

available endpoint for that chemical class. While predicted EECs may approach the predicted 

toxicity levels for sulfonylurea degradates, not enough information is available to support this 

predicted toxicity endpoint to indicate that it is likely to have a different chronic toxicity 
110

endpoint from the parent. Therefore, chronic toxicity data for ring-opened chlorsulfuron are not 

needed to complete a risk assessment and ring-opened chlorsulfuron will be assumed to have a 

similar acute and chronic toxicity to the parent unless data are available to indicate otherwise. If 

data on chlorsulfuron degradates are available, EFED would encourage the registrant to submit 

them to EFED. Unreviewed measured chronic daphnid data data on ring-opened chlorsulfuron 

indicates that chlorsulfuron has a toxicity in the same order of magnitude of chlorsulfuron 

(NOAEC for chlorsulfuron=20 mg/L; NOAEC for ring-opened chlorsulfuron is 11.7 mg/L). 

This supports use of the assumption of similar toxicity for the parent for the evaluation of 

chronic toxicity for ring-opened chlorsulfuron.

The predicted acute toxicity endpoints for ring-opened chlorsulfuron are also lower than those 

measured for parent chlorsulfuron. The lowest predicted endpoints were based on the imide and 

amide class. The amide regression for predicting fish 96-hr LC50s is based on six endpoints for 

fish ranging from 0.3 to 290 mg/L. The amide regression for predicting daphnid 48-hr LC50s is 

based on three endpoints ranging from 2 to 128 mg/L. While the regressions are based on 

limited data, the measured endpoints are within the range of predicted endpoints for ring-opened 

chlorsulfuron. Using a rough estimate of possible exposure for ring-opened chlorsulfuron of 3 

μg/L and the most sensitive predicted acute endpoint for ring-opened chlorsulfuron (7100 μg/L), 

it is not likely that exposure levels could achieve concentrations where a risk concern would 

arise (3/7100 = 0.0004 and the corresponding lowest level of concern is 0.05). Therefore, 

additional data on the acute toxicity of ring-opened chlorsulfuron is not recommended. 

Unreviewed measured acute toxicity data on ring-opened chlorsulfuron and chlorsulfuron both 

yielded nondefinitive endpoints. It is expected that the assumption of similar toxicity for acute 

toxicity will not significantly impact risk conclusions. If data on chlorsulfuron degradates are 

available, EFED would encourage the registrant to submit them to EFED. 

 

Chlorsulfuron (CSF)

5-hydroxychlorsulfuron (OHCSF) O-desmethyl chlorsulfuron (ODCSF)
111

2-chlorosulufronylurea

ring-opened chlorsulfuron (ROC)

Figure I1. Structures of chlorsulfuron, O-desmethyl chlorsulfuron, and 5-

hydroxychlorsulfuron, and 3-chlorosulfonylurea

Table I1. Comparison of measured and estimated toxicity endpoints for chlorsulfuron and 

chlorsulfuron transformation products (estimated using ECOSAR version 1).*

Compound Toxicity Endpoint in mg/L (measured or estimated for chemical class)

96-hr FW fish 

EC50/LC50

(mg/L)

48-hr 

Daphnid LC50

(mg/L)

96-hr EC50

Green Algae

(mg/L)

Fish Chronic 

Value

(mg/L)

Daphnid 

Chronic 

Value

(mg/L)

Sulfonylureas

Chlorsulfuron 

(measured)

>300 (meas)

74 (triaz)

29 (amide)

165 (NO)

>370 (meas)

56 (triaz)

18 (amide)

54 (SU)

98 (NO)

0.05 (meas)

20 (triaz)

0.66 (amide)

0.04 (SU)

47 (NO)

32 (meas)

16 (triaz)

0.17 (amide)

-- (SU)

16 (NO)

20 (meas)

6.2 (triaz)

0.23 (amide)

5.4 (SU)

18 (NO)

ODMC

INM6957

>120 (meas)4

196 (phenol)

1368 (triaz)

188 (amide)

-- (SU)

1247 (NO)

>122 (meas)4

51 (phenol)

471 (triaz)

81 (amide)

286 (SU)

654 (NO)

26.4 (meas)4

252 (phenol)

83 (triaz)

1.3 (amide)

0.038 (SU)

203 (NO)

-- (meas)4

1325 (phenol)

120 (triaz)

1.1 (amide)

-- (SU)

120 (NO)

57.7 (meas)4

9.7 (phenol)

33 (triaz)

0.57 (amide)

27 (SU)

52 (NO)

ROC

IN-JJ998

>96 (meas)4

22 (imide)

9.4 (amide)

-- (SU)

50 (NO)

>102 (meas)4

26 (imide)

7.1 (amide)

20 (SU)

32 (NO)

>70 (meas)4

2.6 (imide)

0.44 (amide)

0.039 (SU)

--

2.1 (imide)

0.0056 (amide)

-- (SU)

4.7 (NO)

11.7 (meas)4

2.3 (imide)

0.094 (amide)

2.1 (SU)

3.5 (NO)

CPSU 6936 (aa)

25929 (amide)

2.5×105 (NO)

323 (aa)

4016 (amide)

91699 (NO)

41 (aa)

5.4 (amide)

8528 (NO)

87 (aa)

153 (amide)

25745 (NO)

8.0 (aa)

53 (amide)

4373 (NO)

Sulfonamides

CSM

INA4097

>124 (meas)3

148 (amide)

1006 (NO)

>129 (meas)3

59 (amide)

516 (NO)

>131 (meas)3

0.79 (amide)

148 (NO)

-- (meas)

0.88 (amide)

98 (NO)

39.3 (meas)

0.79 (amide)

40 (NO)

OHCSM 366 (phenol)

386 (amide)

30 (phenola)

2779 (NO)

73 (phenol)

131 (amide)

2.1 (phenola)

1344 (NO)

390 (phenol)

1.2 (amide)

12.7 (phenola)

318 (NO)

0.006 (phenol)

2.3 (amide)

1.2 (phenola)

273 (NO)

14 (phenol)

1.7 (amide)

1.2 (phenola)

96 (NO)

Triazines

TA

INA4098

>0.93 (meas)2

49 (aniline)

474 (triaz)

>99 (meas)2

1.9 (aniline)

171 (triaz)

>10 (meas)4

7.7 (aniline)

31 (triaz)

-- (meas)

0.21 (aniline)

44 (triaz)

97 (meas)

0.04 (aniline)

12 (triaz)
112

Compound Toxicity Endpoint in mg/L (measured or estimated for chemical class)

96-hr FW fish 

EC50/LC50

(mg/L)

48-hr 

Daphnid LC50

(mg/L)

96-hr EC50

Green Algae

(mg/L)

Fish Chronic 

Value

(mg/L)

Daphnid 

Chronic 

Value

(mg/L)

454 (NO) 239 (NO) 76 (NO) 44 (NO) 19 (NO)

DT 1235 (triaz)

54 (phenolp)

858 (NO)

334 (triaz)

383 (phenolp)

433 (NO)

48 (triaz)

1.4 (phenolp)

118 (NO)

83 (triaz)

20 (phenolp)

83 (NO)

20 (triaz)

153 (phenolp)

33 (NO)

TU

INV7160

> 1 (meas)1

336 (surea)

1746 (triaz)

177 (amide)

1219 (NO)

>1.3 (meas)1

749 (surea)1

464 (triaz)

68 (amide)

615 (NO)

>10,>11(meas)1

0.13 (surea)

68 (triaz)

0.82 (amide)

168 (NO)

-- (meas)

4.6 (surea)

119 (triaz)

1.0 (amide)

119 (NO)

-- (meas)

51 (surea)

29 (triaz)

0.90 (amide)

47 (NO)

OHTA

INB5528

157 (aniline)

388 (phenol)

8264 (triaz)

24 (phenola)

3209 (NO)

2.7 (aniline)

69 (phenol)

1332 (triaz)

1.4 (phenola)

1490 (NO)

8.7 (aniline)

376 (phenol)

122 (triaz)

308 (phenola)

307 (NO)

0.77 (aniline)

0.004 (phenol)

317 (triaz)

317 (phenola)

317 (NO)

0.07 (aniline)

13 (phenol)

59 (triaz)

100 (phenola)

100 (NO)

Prometron 7.7 (meas)5 17.7 (meas)5,6 0.5 (meas)5,7 3.45 (meas)5 20 (meas)5

Others

AB 3420 (imide)

1564 (amide)

12573 (NO)

3031 (imide)

380 (amide)

5485 (NO)

17 (imide)

1.5 (amide)

872 (NO)

343 (imide)

9.2 (amide)

1277 (NO)

174 (imide)

5.0 (amide)

330 (NO)

Meas=measured; SU=sulfonylurea; NO=neutral organic; triaz=triazine; aa=aliphatic amine; phenola=phenol amine; 

phenolp=phenols, poly; surea=substituted ureas

* Blue values are measured values. Black values were estimated by ECOSOAR version 1.0. Purple and bold

values indicate that the endpoint was much lower than that measured for the parent. Estimated toxicity endpoints 

are only used to prioritize which degradates are likely a risk concern and how they should be handled in the risk 

assessment. The estimated values may over or under estimate actual toxicity of the compounds. 

Appendix B provides the output from ECOSAR. 1

 This degradate is a thifensulufron-methyl degradate. Data are available for rainbow trout (Onchorychus mykiss), 

daphnia, S. capricornutum, and Lemna gibba in the EU Monograph for thifensulfuron-methyl. These data have not 

been reviewed by the USEPA.

2 Data on the toxicity of triazine amine are available in the IUPAC Footprint Database (AERU, 2012). A Lemna

and algae EC50 were also reported at 10 mg/L. These data have not been reviewed by the USEPA. 3 Data on the toxicity of chlorosulfonamide are available in the footprint database. The fish acute NOAEC was 

reportedly 124 mg/L, daphnid acute NOAEC was 129 mg/L, Lemna 7-day EC50 was 26.5 mg/L, and the algae 

NOAEC was 131 mg/L. Data are also available on Collembola (28-day NOAEC = 0.9 mg/L) and earthworms. 

These data have not been reviewed by the USEPA.

4 Data were obtained from a draft risk assessment prepared by the European Commission (AERU, 2012). Data have 

not been reviewed by the EPA. 

5 Data represent the most sensitive endpoint reported for prometron in the EFED Pesticide Ecotoxicity Database 

searched on August 9, 2012. Only studies conducted on the technical product or with greater than 98% a.i. were 

examined.

6 Endpoint reported is for the mysid (Americamysis bahia). 7 The marine diatom (Phaeodactylum tricornutum) was more sensitive than green algae for prometon and the 

reported endpoint was 0.23 mg/L.

Triazines

Triazine amine, hydroxy triazine amine, triazine urea, and dihydroxy triazine are all triazines 

observed in chlorsulfuron fate studies. The structures of these compounds are shown in Figure 
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I2. These compounds lack the sulfonylurea bridge, and are thus likely to act by a different mode 

of action than parent chlorsulfuron. Toxicity data on the triazine amine and triazine urea are 

available from the International Union of Pure and Applied Chemistry (IUPAC) Footprint 

Database (AERU, 2012), and from a draft chlorsulfuron risk assessment from the European 

Commission (European Commission, 2007). Additionally, toxicity data on prometron (a triazine 

herbicide with a similar structure) were evaluated for more perspective on the potential toxicity 

of the triazine degradates. The lowest measured acute endpoint for the triazines was 7.7 mg/L, 

and the lowest chronic or plant endpoint was 0.5 μg/L. Given that the highest EEC reported for 

the parent was orders of magnitude lower than this at 9.5 μg/L, it is unlikely that aquatic 

concentrations will be sufficiently high to elicit a toxicity concern for these degradates.15,16 This 

indicates that the triazines need not be considered residues of concern for chlorsulfuron. 

Triazine Amine Hydroxyl triazine

Triazine urea Dihydroxy triazine

 Prometron

Figure I2. Structures of triazine amine, triazine urea, dihyrdroxy triazine, and hydroxy 

triazine, and prometron (a triazine herbicide with toxicity data available).

Sulfonamides

Chlorosulfonamide is a major degradate observed in laboratory studies and in lysimeter studies. 

The only definitive endpoint for chlorsulfonamide was 39.3 mg/L for daphnid (Table 6). This 

value is within an order of magnitude of the daphnid chronic endpoint for the parent of 20 mg/L. 

ECOSAR predicted a chronic endpoint that was lower than that measured for parent 

 15 EEC/Toxicity endpoint = 9.5 μg/L / 7700 μg/L = 0.001; this value is much lower than the acute LOC of 0.05. 16 EEC/Toxicity endpoint = 9.5 μg/L / 500 μg/L = 0.019;this value is much lower than the plant LOC of 1.0.
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chlorsulfuron (Daphnids: 0.79 mg/L for chlorsulfonamide versus 20 mg/L for parent); however, 

EECS are not expected to approach levels that could result in a risk concern (9.5 μg/L/790 

μg/L=0.01). As exposure to chlorosulfonamide is expected to be lower than to exposure to 

parent chlorsulfuron, it is assumed that a risk assessment based on parent chlorsulfuron will be 

protective of the potential exposure due to exposure to chlorosulfonamide. This degradate will 

not be considered as residues of concern in a total toxic residue approach because it does not 

retain the sulfonylurea group.

Estimating Exposure to Total Residues

The ecological risk assessments identified ring-opened chlorsulfuron and 2-

chlorophenylsulfonylurea as residues of concern for chlorsulfuron. Both of these residues were 

major residues observed in laboratory and field studies. Therefore, data on the sorption 

coefficients of these degradates are needed to permit estimation of concentrations of total toxic 

residues in water. O-desmethyl chlorsulfuron is expected to have mobility similar to that of the 

parent; therefore, data on the parent compound may be used to estimate soil sorption of this 

degradate. EPIWEB version 1.4 predicted KOC values of 124, 423, and 1 L/kg-organic carbon 

for chlorsulfuron, ring opened chlorsulfuron, and 2-chlorophenylsulfonylurea, respectively. 

These differences in sorption coefficients had little impact on the estimated EEC using 

PRZM/EXAMs. In the absence of additional data, sorption coefficients will be estimated using 

the current version of EPIWEB (USEPA, 2009b).