ii 

The Environmental Fate and Effects Division (EFED) and Antimicrobials Division (AD) have 

completed the preliminary problem formulation (attached) for the environmental fate, ecological 

risk, endangered species, and drinking water exposure assessments to be conducted as part of the 

Registration Review of the organochlorine fungicide, mildewcide, algicide, and acaricide, 

chlorothalonil. This document is intended to provide an overview of what is currently known 

regarding the environmental fate and ecological effects associated with registered uses of 

chlorothalonil and its degradation products, and outlines uncertainties regarding attributes of the 

parent compound and its transformation products. It describes the preliminary ecological risk 

hypothesis and the processes that will be used during the completion of drinking water and 

ecological risk assessments in support of Registration Review. Within OPP, the EFED is 

responsible for assessing the conventional agricultural food and non-agricultural turf uses of 

chlorothalonil and the AD is responsible for assessing the wood and material preservative and 

material additive uses of chlorothalonil. 

This problem formulation outlines the plan to be utilized in the risk assessment of chlorothalonil. 

The risk assessment will consider not only parent chlorothalonil, but also the major degradate of 

toxicological concern, SDS-3701 (other degradates may be considered if additional information 

indicates they are of toxicological concern), and manufacturing by-products of concern, 

including hexachlorobenzene (HCB) and congeners (structurally related chemicals) of 

polyhalogenated dibenzo-p-dioxins/dibenzofurans (dioxins/furans). This document also 

recommends studies that should be included in a data call-in (DCI) to address uncertainties 

surrounding the environmental fate and potential ecological effects of chlorothalonil. In addition 

to the DCI recommendations, EPA is requesting additional information from the chlorothalonil 

registrants to establish the levels of the known chlorothalonil impurities [i.e., hexachlorobenzene 

(HCB) and dioxin/furans] in currently registered products. Additional details are provided in the 

problem formulation. 

 
1 

REGISTRATION REVIEW 

Preliminary Problem Formulation for the Environmental Fate, Ecological Risk, Endangered 

Species and Drinking Water Assessments for: 

Chlorothalonil 

2,4,5,6-Tetrachloroisophthalonitrile 

Prepared by: 

Amy Blankinship, Chemist 

Rochelle Bohaty, PhD, Chemist 

Tanja Crk, MA, Biologist 

Melissa Panger, PhD, Senior Scientist 

Reviewed by: 

Rosanna Louie-Juzwiak, Risk Assessment 

Process Leader 

Dana Spatz, Branch Chief 

U. S. Environmental Protection Agency 

Office of Pesticide Programs 

Environmental Fate and Effects Division 

Environmental Risk Branch 3 

1200 Pennsylvania Ave., NW 

Mail Code 7507P 

Washington, DC 20460 

Srinivas Gowda, Microbiologist 

William Erickson, PhD, Biologist 

Najm Shamim, PhD, Chemist 

Nader Elkassabany, PhD, Branch Chief 

U.S. Environmental Protection Agency 

Office of Pesticide Programs 

Antimicrobials Division 

Risk Assessment and Science Support Branch 

1200 Pennsylvania Ave., NW 

Mail Code 7510P 

Washington, DC 20460 

March 22, 2012 

Cl

Cl Cl

Cl

N

N
2 

TABLE OF CONTENTS 

I. Purpose .............................................................................................................. 3

II. Problem Formulation ....................................................................................... 3

A. Nature of Regulatory Action ........................................................................................... 3

B. Previous Assessments ..................................................................................................... 4

C. Stressor Source and Distribution .................................................................................... 6

D. Environmental Fate and Transport ............................................................................... 30

E. Ecological Effects ......................................................................................................... 51

F. Analysis Plan ................................................................................................................ 78

G. Preliminary Identification of Data Gaps ....................................................................... 87

H. Effects ........................................................................................................................... 91

I. Other Information Needs .............................................................................................. 96

APPENDIX A. References ...................................................................................... 98

Appendix B: Submitted Environmental Fate and Ecological Studies for the Registration 

of Chlorothalonil ..................................................................................................... 100

APPENDIX C: Environmental Fate Studies Kinetic Analyses .......................... 124

APPENDIX D: DCI Justification Tables .............................................................. 133

APPENDIX E: SIP Input and Output .................................................................. 144

Appendix F: Stir Input and Output ...................................................................... 146
3 

I. PURPOSE 

The purpose of this problem formulation is to provide the status of the environmental fate and 

ecological effects of chlorothalonil based on currently registered uses. This document provides a 

plan for analyzing data relevant to chlorothalonil and for conducting environmental fate, 

ecological risk, endangered species and drinking water exposure 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 

environmental fate and ecological risk associated with the registered uses of chlorothalonil.

II. PROBLEM FORMULATION 

A. NATURE OF REGULATORY ACTION

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

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

Agency (EPA, or ‘the Agency’). In determining whether a pesticide can be registered in the 

United States, EPA evaluates its safety to non-target species based on a wide range of 

environmental and health effects studies. In 1996, FIFRA was amended by the Food Quality 

Protection Act (FQPA), and the Agency was mandated to implement a new program for the 

periodic review of pesticides, i.e., registration review.1

 The Registration Review program is 

intended to ensure that, as the ability to assess risk evolves and as policies and practices change, 

all registered pesticides continue to meet the statutory standard of no unreasonable adverse 

effects to human health and the environment. Changes in science, public policy and pesticide use 

practices will occur over time. Through the new Registration Review program, the Agency 

periodically reevaluates pesticides to make sure that as change occurs, products in the 

marketplace can be used safely. 

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

FIFRA, the Agency is beginning its evaluation of chlorothalonil to determine whether it 

continues to meet the FIFRA standard for registration. This problem formulation for the 

environmental fate, ecological risk, endangered species and drinking water assessment chapter in 

support of the registration review will be posted in the initial docket which will open the public 

phase of the review process. This problem formulation considers all current and active 

registrations for chlorothalonil. 

Problem formulations provide a strategic framework for the risk assessment. By identifying the 

important components of the problem, it focuses the assessment on the most relevant life history 

stages, habitat components, chemical properties, exposure routes and endpoints. The structure of 

this risk assessment is based on guidance contained in U.S. EPA’s Guidance for Ecological Risk 

Assessment (U.S. EPA 1998a), the Services’ Endangered Species Consultation Handbook (U.S. 

FWS/NMFS 1998) and is consistent with procedures and methodology outlined in the Overview 

Document (U.S. EPA, 2004) and reviewed by the U.S. Fish and Wildlife Service and National 

Marine Fisheries Service (U.S. FWS/NMFS 2004). 

 

1

 (http://www.epa.gov/oppsrrd1/registration_review/) 
4 

B. PREVIOUS ASSESSMENTS

Ecological Risk Assessments 

Chlorothalonil has a long regulatory history, and a number of ecological risk assessments have 

been completed. Risk to non-target organisms was evaluated for conventional uses of 

chlorothalonil as part of the Re-registration Eligibility Decision (RED) in April 1999. A 

quantitative ecological risk assessment was not performed for antimicrobial chlorothalonil uses 

at the time of the RED because the Agency did not anticipate any exposure of concern to fish, 

wildlife, and/or endangered species based on the registered use patterns; furthermore, discharge 

to the environment complied with all Federal disposal laws and NPDES. For registration review, 

the Agency anticipates the need to conduct a comprehensive ecological risk assessment for both 

conventional and antimicrobial uses of chlorothalonil. 

For conventional pesticide uses in the 1999 RED document, exceedances of the Agency’s 

presumptive level of concern (LOC) values included exceedances for birds, mammals, fish, 

aquatic invertebrates and aquatic plants. According to the RED, as part of the outlined ecological 

risk mitigation measures for conventional uses, the chlorothalonil registrants agreed to revise 

their product labels to include maximum individual application rates, minimum application 

intervals, and maximum seasonal application rates. Additionally, the registrants agreed to 

include a requirement for untreated buffers between treated agricultural fields and 

marine/estuarine water bodies (150 ft for aerial and air-blast applications and 25 ft for ground 

applications). 

As part of a recent “me-too” registration for turf and ornamentals (DP328075, 220223, 301503, 

301500; June 2006), new data were submitted that indicated greater toxicity of chlorothalonil to 

birds and daphnids than the data used in the 1999 RED. Additionally, ecological risk assessments 

for IR-4 uses on multiple crops (e.g., fruiting vegetables, cucurbit vegetables, okra, persimmon, 

horseradish, rhubarb, ginseng, yams, lupine, lentils, brassica head and stem vegetables) have 

been conducted since the 1999 RED. The potential risks identified from the new uses were 

similar to those previously reported in the RED. 

In October 2007, the Agency completed an assessment of the potential direct and indirect effects 

of conventional uses of chlorothalonil to the California red-legged frog (CRLF) and potential 

modification to designated critical habitat from uses of chlorothalonil. Based on the information 

available at that time the Agency made a May Affect and Likely to Adversely Affect 

determination for the CRLF from the use of chlorothalonil. Additionally, the Agency determined 

that there is the potential for modification of CRLF designated critical habitat from the use of 

chlorothalonil. 

According to the 1999 RED document for chlorothalonil, the 1984 Registration Standard for 

chlorothalonil required that levels of hexachlorobenzene (HCB), an impurity in technical 

chlorothalonil, be at or below 0.05%. Certification of HCB levels was required in the RED. 

Additionally, there was a 1987 Data Call-In (DCI) to identify and indicate the amount of other 

known impurities in technical chlorothalonil (i.e., dioxins and dibenzofurans) via revised 

Confidential Statements of Formula (CSFs). At the time of the RED, these data were still 

outstanding. These impurities have not been considered in past ecological risk assessments; 
5 

however, they will be considered in the ecological risk assessment conducted for chlorothalonil 

as part of the Registration Review process. 

After reviewing the previous risk assessments, modifications to the risk analyses are expected 

during the Registration Review Process. These changes are expected to be due, in part, to an 

evolution of Agency policy, exposure model development, and additional data requirements. For 

example, the environmental fate and ecological toxicity data were reevaluated as part of the 

problem formulation phase of the Registration Review process and changes in guideline 

standards and policies or in some cases the study reevaluation and interpretation of the study 

resulted in the selection of different endpoints. 

Drinking Water Exposure Assessments 

Several drinking water assessments (DWAs) have been completed for chlorothalonil. As part of 

the 1999 RED, a drinking water exposure assessment was completed for conventional uses. A 

DWA exposure assessment was not performed specifically for antimicrobial chlorothalonil uses 

at the time of the RED because the Agency did not anticipate any exposure of concern based on 

the registered antimicrobial use patterns and that discharges to the environment complied with all 

Federal disposal laws and NPDES. 

The 1999 RED drinking water exposure assessment performed included a review of groundwater 

and surface water monitoring data and was based on these data. Model simulations were not 

performed or used for the drinking water exposure assessment.2

 The Agency used groundwater 

monitoring data [a 16 μg/L combined concentration of four environmental transformation 

products: 3-carbamoyl-2,4,5-trichlorobenzoic acid (SDS-46851), 3-cyano-6-hydroxy-2,4,5-

trichlorobenzamide (SDS-47525), 4-hydroxy-2,5,6-trichloro-1,3-dicyanobenzene (SDS-3701), 

and 3-cyano-2,4,5,6-tertachlorobenzamide (SDS-19221)] from New York to represent the 

potential exposure to chlorothalonil and other potentially toxic transformation products. 

Since the RED, several drinking water assessments have been completed for chlorothalonil. 

These assessments have utilized Tier I groundwater and Tier II surface water modeling for 

estimating exposure to chlorothalonil and its transformation product of toxicological concern, 

SDS-3701. Monitoring data have also been considered in these assessments; however, these data 

have not been recommended for use in the Human Health Assessment. The monitoring data was 

not recommended for use because: 1) the monitoring data do not specifically target 

chlorothalonil; 2) the number of samples taken at an individual site during a one year period is 

limited; 3) the reported data are several years old and may not accurately reflect current use 

patterns; and 4) available monitoring data do not include degradates, and, therefore, do not 

capture the potential exposure risk to total toxic chlorothalonil residues. In support of the 2010 

IR-4 registration of chlorothalonil (Bravo Weather Stick®, 54%) new uses on bulb vegetables, 

bushberries and low growing berries, a DWA was completed (DP 370488).3

 This recent 

 

2

 Frankenberry, M. Craqven, H. Clem, A. Wolf, J. Nelson, H. EFED RED Science Chapter for Chlorothalonil, 

October 20, 1997 DP Codes 224421, 226857, 229496, 229499, 237908, 237908 

3

 R. Bohaty, Drinking Water Assessment for the IR-4 Registration of Chlorothalonil (Bravo Weather Stick®, 54%) 

and the Degradation Product, 4-Hydroxy-2,5,6-trichloro-1,3-dicyanobenzene (SDS-3701) for the New Uses On: 

Bulb Vegetables, Bushberries, and Low Growing Berries (PC Code: 081901; DP Barcode: 370488) 
6 

assessment determined that chlorothalonil uses on horseradish, which was previously determined 

(DP 346321)4

 to result in the most conservative estimated drinking water concentrations 

(EDWCs) of all chlorothalonil uses, was still the use that resulted in the most conservative 

EDWC (1 in 10 year peak concentration of 316 μg/L based on Tier II surface water modeling) of 

all currently registered uses of chlorothalonil. Past DWAs completed for chlorothalonil uses on 

turf also yielded very high EDWCs; however, turf application rates have been reduced in recent 

years reducing the corresponding EDWCs. 

C. STRESSOR SOURCE AND DISTRIBUTION

Chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile; CAS 1897-45-6) is a broad spectrum, nonsystemic pesticide. Chlorothalonil is mainly used as a fungicide to control fungal foliar diseases 

of vegetable, field, and ornamental crops; however, chlorothalonil is also registered for use as an 

industrial and consumer wood preservative, a fungicidal/mildewcidal/algicidal paint, stain, and 

coating film preservative, and a material preservative paper and paperboard (non-food contact) 

and for the “in-service” life of caulks and sealants, adhesives, grouts and joint compounds, 

wallboard, stucco. The chemical structure of chlorothalonil is provided in Figure 1. Table 1

includes chemical identification and physical chemical properties of chlorothalonil. 

 

Figure 1. Chemical Structure of Chlorothalonil 

Table 1. Chemical Identification Information for Chlorothalonil 

Parameter Value Source/Classification 

(Comments) 

Chemical Name 2,4,5,6-tetrachloroisophthalonitrile ChemDraw Ultra 

Chemical Abstracts Service 

(CAS) Registry Number 1897-45-6 CAS Registry 

Molecular Formula C8Cl4N2 ChemDraw Ultra 

USEPA Pesticide Code (PC #) 081901 Not applicable 

Smiles Notation C1(=C(C(=C(C(=C1Cl)C#N)Cl)Cl)Cl)C#N Pubchem 

Molecular Mass 265.9 g/mol ChemDraw Ultra 

Melting point 250-251°C MRID 42354608, Acc. No. 

143749 

Boiling point 350°C (760 mmHg) MRID Nos. 42354608, Acc. 

No. 143749 

Density 

Specific Gravity 

1.8 g cm−3

, solid 

1.8 at 25 deg C/4 deg C 

Relative density (water = 1): 1.8 

MRID 40047601 

Dissociation Constant in Not applicable Chlorothalonil is a neutral 

 

4

 L. Shanaman, Drinking Water Assessment for the IR-4 Registration of Chlorothalonil (Bravo Weather Stick®, 

54%) and the Degradation Product, 4-Hydroxy-2,5,6-trichloro-1,3-dicyanobenzene (SDS-3701) for the New Uses 

on: Fruiting Vegetables, Cucurbit Vegetables, Okra, Persimmon, Horseradish, Rhubarb, Ginseng, Yam, Lupine, 

Lentils and Brassica Head and Stem Vegetables (PC Code: 081901; DP Barcode: 346321). 

Cl

Cl Cl

Cl

N

N
7 

Water molecule that does not 

dissociate to ionic species in 

aqueous solution. 

MRID 42354608, Acc. No. 

143749 

Vapor Pressure 

5.72 x 10-7 torr (25 °C) 

2.65 x 10-6 torr (35 °C) 

2.65 x 10-5 torr (45 °C)

Acc. No. 259753 

scientifically valid 

Water Solubility 0.8-0.96 mg/L 1999 RED 

Henry’s Law Constant 2.6 x 10-7 atm - m3/mol 1999 RED 

Log Kow 3.8 (Kow = 6277) 1999 RED 

The manufacturing processes for chlorothalonil are known to result in impurities including: 

hexachlorobenzene (HCB), polychlorinated dioxins (D), and dibenzofurans (F), as well as other 

possible organochlorine contaminants. These chemicals have been found in technical grade 

chlorothalonil, as well as formulated chlorothalonil products; however, the levels are low (39 ng 

DF/g a.i.).5

 Formulation documentation confirms low levels of HCB in currently registered 

chlorothalonil products; however, there is no information provided on the other types of 

contaminants mentioned above. 

Several environmental transformation products of chlorothalonil are known including the major 

transformation products: SDS-3701, SDS-46851, 3-cyano-2,4,5-trichlorobenzamide (SDS47523), 2-amido-3,5,6-trichloro-4-cyanobenzenesulfonic acid (R417888), sodium 2,4-bis-amido3,5,6-trichlorobenzenesulfonate (R471811), 4-amindo-2,5-dichloro-6-cyanobenzene-1,3-

disulphonic acid (R419492), 5-cyano-4,6,7-trichloro-2H-1,2-benzisothiazol-3-one (SDS-67042), 

2,5,6-trichloro-1,3-dicyanobenzene-4-sulphonate, trichloro-1,3-dicyanobenzene and 2,5,6-

trichloro-4-(glutathio-S-yl)isophthalonitrile (SDS-66382). There are also numerous minor 

transformation products. Additional discussion of the formation of chlorothalonil transformation 

products in the environment is provided in the Environmental Fate and Transport section of this 

document. 

The only transformation product previously considered of toxicological concern is SDS-3701. 

This metabolite is also known to form under various laboratory test conditions, as well as in the 

environment. The chemical structure of SDS-3701 is provided in Figure 2. Given that there are 

uncertainties in the fate profile for chlorothalonil regarding the potential for degradates/ 

transformation products, if additional information becomes available, the evaluation of 

chlorothalonil and any transformation products deemed to be of toxicological concern will be 

evaluated during the risk assessment phase of the Registration Review process by incorporating 

the total toxic residue approach when deriving aquatic and terrestrial environmental 

concentrations. See Table 2 for the fate properties of SDS-3701. 

 

5

 Holt. E.; Weber, R.; Stevenson, G.; Gaur, C. Environ. Sci. Technol. 2010, 44, 5409-5415. 

Cl

Cl OH

Cl

N

N
8 

Figure 2. Chemical Structure of SDS-3701, 4-hydroxy-2,5,6-trichloro-1,3-dicyanobenzene 

Table 2. Chemical Identification Information for SDS-3701, 4-hydroxy-2,5,6-trichloro-1,3-

dicyanobenzene 

Parameter Value Source/Classification 

(Comments) 

Chemical Name 4-hydroxy-2,5,6-trichloro-1,3-dicyanobenzene ChemDraw Ultra 

Chemical Abstracts Service 

(CAS) Registry Number 28343-61-5 CAS Registry 

Molecular Formula C8Cl3N2OH ChemDraw Ultra 

USEPA Pesticide Code Not applicable -- 

Smiles Notation C1(=C(C(=C(C(=C1Cl)C#N)O[H])Cl)Cl)C#N Pubchem 

Molecular Mass 247.5 g/mol ChemDraw Ultra 

Vapor Pressure (25 °C) 6.1 x 10-7 mm Hg Modified Grain Method 

EPI Suite (v4.00) 

Water Solubility 88 mg/L (fragment estimate) v1.01 

EPI Suite (v4.00) 

Henry’s Law Constant 2.2 x 10-11 atm/m3

/mol (bond method) 

2.8 x 10-11 atm/m3/mol (group method) EPI Suite (v4.00) 

Log Kow 3.1 WSKOW v1.41 

EPI Suite (v4.00) 

EPA does not routinely include in its risk assessments an evaluation of active ingredient mixtures 

- either mixtures of multiple active ingredients in product formulations or an applicator tank mix. 

In the case of the product formulations of active ingredients (a.i.) (that is, a registered product 

containing more than one active ingredient), each active ingredient is subject to an individual 

risk assessment for regulatory decision-making regarding the active ingredient on a particular use 

site. If effects data are available for a formulated product containing more than one active 

ingredient, and demonstrate potentially enhanced toxicity to a non-target organism from 

exposure to the multiple a.i.’s, these data may be used qualitatively or quantitatively in 

accordance with the Agency’s Overview Document and the Services’ Evaluation Memorandum 

(U.S., EPA 2004; USFWS/NMFS 2004, respectively) for risk assessment purposes. 

There are 34 registered end-use products that contain multiple active ingredients, including 

chlorothalonil (see Table 3). Acute oral mammalian LD50 data for multiple active ingredient 

end-use products which can be expressed as chlorothalonil relative to the single active ingredient 

are available for several of the multi-active ingredient formulations. These data, along with other 

data available on chlorothalonil mixtures, will be considered in the risk assessment conducted for 

the chlorothalonil registration review. 

 
9 

Table 3. Conventional and Antimicrobial Chlorothalonil Formulated Products that 

Contain More than One Active Ingredient 

Product EPA Registration 

Number % Active Ingredient (PC Code) 

RIDOMIL GOLD BRAVO 100-800 72% Chlorothalonil (081901) 

4.5% Metalaxyl-M (113502) 

QUADRIS OPTI 100-1171 46% Chlorothalonil (081901) 

4.6% Azoxystrobin (128810) 

TILT BRAVO SE 100-1192 38.5% Chlorothalonil (081901) 

2.9% Propiconazole (122101) 

RIDOMIL GOLD BRAVO SC 100-1221 33.1% Chlorothalonil (81901) 

3.3% Metalaxyl-M (113502) 

INSTRATA 100-1231 

1.2% Fludioxonil (071503) 

29.9% Chlorothalonil (081901) 

4.7% Propiconazole (122101) 

REVUS OPTI 100-1279 3.3% Mandipropamide Technical 0(36602) 

33.3% Chlorothalonil (081901) 

RENOWN FUNGICIDE 100-1315 45% Chlorothalonil (081901) 

3% Azoxystrobin (128810) 

CONCERT II (FUNGICIDE) 100-1347 

38.5% Chlorothalonil (081901) 

2.9% Propiconazole (122101) 

DACONIL ACTION 100-1364 

0.1% 1,2,3-Benzothiadiazole-7-carbothioic acid, 

S-methyl ester (06140 2) 

53.9% Chlorothalonil (081901) 

NUFARM TM + CTN SPC 66.6 

WDG FUNGICIDE 228-638 50% Chlorothalonil (081901) 

16.7% Thiophanate-methyl (102001) 

TM + CTN E-PRO 90 WDG 

FUNGICIDE 228-639 72% Chlorothalonil (081901) 

18% Thiophanate-methyl (102001) 

RESERVE FUNGICIDE 432-1486 40% Chlorothalonil (081901) 

5% Triticonazole (125620) 

CUPRINOL STAIN AND 

WOOD PRESERVATIVE 577-544 0.7% Chlorothalonil (081901) 

0.3% Bis(tributyltin) oxide (083001) 

SPECTRO 90 WDG 1001-72 72% Chlorothalonil (081901) 

18% Thiophanate-methyl (102001) 

NEXGEN 1022-583 14.7% Methylene bis(thiocyanate) (068102) 

14.5% Chlorothalonil (081901) 

DENSIL CA 1258-1270 

47% Chlorothalonil (081901) 

6% N-Cyclopropyl-N'-(1,1-dimethylethyl)-6-

(methylthio)-1,3,5-triaz ine-2,4-diamine (128996) 

FUNGITROL 2010 1529-47 

20.1% Chlorothalonil (081901) 

10.1% 3-Iodo-2-propynyl butylcarbamate 

(107801) 

FUNGITROL 2002 1529-48 

48% Chlorothalonil (081901) 

5.9% N-Cyclopropyl-N'-(1,1-dimethylethyl)-6-

(methylthio)-1,3,5-triaz ine-2,4-diamine (128996) 

HELENA BRAVO S 5905-472 27.3% Sulfur (077501) 

19.2% Chlorothalonil (081901) 

THE ANDERSONS 3-WAY 

SNOW MOLD FUNGICIDE 9198-227 

7.5% Benzene, pentachloronitro- (056502) 

3.9% Chlorothalonil (081901) 

0.6% Propiconazole (122101) 

TERRANIL S 9779-337 27.3% Sulfur (077501) 
10 

Product EPA Registration 

Number % Active Ingredient (PC Code) 

19.2% Chlorothalonil (081901) 

CONSYST WDG 48234-7 50% Chlorothalonil (081901) 

16.7% Thiophanate-methyl (102001) 

FLOURONIL FUNGICIDE 55146-81 72% Chlorothalonil (081901) 

4.4% Metalaxyl-M (113502) 

ANTIBLU MC-30 62190-30 14.7% Methylene bis(thiocyanate) (068102) 

15.5% Chlorothalonil (081901) 

DISARM C FUNGICIDE 66330-379 2.4% Fluoxastrobin (028869) 

38.4% Chlorothalonil (081901) 

ACTICIDE PM 67071-2 19% Diuron (035505) 

14.7% Chlorothalonil (081901) 

ACTICIDE PM FLOWABLE 67071-15 19% Diuron (035505) 

14.7% Chlorothalonil (081901) 

ACTICIDE SR-1216/6 67071-17 

19% Diuron (035505) 

8.8% Chlorothalonil (081901) 

6% Octhilinone (099901) 

THOR GMBH ACTICIDE PAX 67071-39 

19% Diuron (035505) 

11.8% Chlorothalonil (081901) 

6% Octhilinone (099901) 

MONCUT CL FLOWABLE 71711-2 38.6% Chlorothalonil (081901) 

10.3% Flutolanil (128975) 

NAI-301 4 SE FUNGICIDE 71711-24 

21.7% Chlorothalonil (081901) 

1.8% Propiconazole (122101) 

17.2% Flutolanil (128975) 

INTACE FUNGICIDE B-6773 74075-1 28.3% Chlorothalonil (081901) 

12.1% p-Tolyl diiodomethyl sulfone (101002) 

PEREGRINE 81943-7 50% Chlorothalonil (081901) 

16.7% Thiophanate-methyl (102001) 

TEE-1 UP WDG FUNGICIDE 83070-2 50% Chlorothalonil (081901) 

16.7% Thiophanate-methyl (102001) 

Pesticidal Mechanism of Action 

Chlorothalonil acts on mold, mildew, stain, and rot-causing fungi, staining and disfiguring algae, 

bacteria and microbes. Chlorothalonil targets multiple sites of the fungal pathogen upon contact 

(FRAC, 2011) affecting various enzymes and other metabolic processes in fungi; however, the 

exact mechanism of action is unknown. Chlorothalonil is believed to combine with glutathione in 

fungal cells tying up available glutathione. It inhibits spore germination, and is toxic to fungal 

cell membranes. Unlike many other fungicides, chlorothalonil resistance has not been reported. 

The mode of action for algae and bacteria is unknown. 

Overview of Pesticide Use and Usage 

Conventional use registrations of chlorothalonil consist of use on a variety of terrestrial food and 

feed crops, terrestrial non-food crops, and greenhouse food/non-food crops. Antimicrobial use 

registrations of chlorothalonil permit its use as an industrial and consumer wood preservative, a 

materials preservative, and as a fungicide/mildewcide/algaecide paint, stain, and coating film 

preservative. Chlorothalonil is formulated in solid form as dust, water dispersible granules, 
11 

pellets, tablets, and as a wettable powder. In liquid form, chlorothalonil is available as an 

emulsifiable, flowable, and soluble concentrate as well as a ready-to-use solution. 

For conventional uses chlorothalonil is used as a preventative treatment and it is applied either 

by aerial or ground equipment, and can be used in tank mixes. A summary of the conventional 

pesticide agricultural and non-agricultural uses of chlorothalonil is provided in the sections 

below based on information from the Biological and Economic Analysis Division (BEAD).6

Total chlorothalonil use is estimated to be approximately 13.5 million pounds per year. 

For antimicrobial uses, chlorothalonil is also used as a preventative treatment. It can be applied 

to wood either at the industrial scale by dipping, spraying or pressure treatment and for consumer 

products (paints, stains and coatings) by hand spray or brush. Chlorothalonil is also mixed or 

blended into materials (e.g., paints, stains, stucco, adhesives, caulk) using a variety of methods 

depending upon the material. For the most part these are blended at the industrial or 

manufacturing scale, the exception is post-manufacturing paint additive products. There are 

wood preservative stains and coatings for use by professionals or the public which can be handspray, brush or pad applied. Similarly there are exterior and interior film preservatives (paints, 

stains and coatings) which can be applied to a variety of surface materials including wood, metal, 

masonry, and concrete by professionals or the public by hand-spray, brush or pad. A summary of 

the antimicrobial uses is available in the Summary of Registered Antimicrobial Uses of 

Chlorothalonil in Support of the Registration Review Summary Document available in the 

docket. 

Agricultural Uses

Chlorothalonil is labeled for use on hundreds of terrestrial food crops including: almond, apricot, 

asparagus, banana, bean (dry), bean (snap, succulent), broccoli, Brussels sprouts, cabbage, carrot, 

cauliflower, celery, cherry (sweet and tart), cocoa bean, coffee bean, corn (sweet), cucumber, 

ginseng, horseradish, lentils, lupine, mango, melon, mushroom, nectarine, okra, papaya, parsnip 

(root), passion fruit, pea (edible-podded), peach, peanut, persimmon, pistachio, plum (fresh and 

prune), pumpkin, rhubarb, soybean, squash (summer and winter), tomato and yam, and bulb 

vegetables. 

Based on private market pesticide usage data from 1998-2010, the annual total agricultural usage 

averaged approximately nine million pounds for eight million treated acres. For these same 

years, the largest markets in terms of total pounds active ingredient applied are peanuts (37%), 

potatoes (26%) and tomatoes (8%). The crops with the most total area treated (total land) are 

peanuts (42%), potatoes (31%) and tomatoes (6%). The maximum percent cropped area treated 

for chlorothalonil is for peanuts (80%), celery (70 %), tomatoes (70%) and watermelons (65%).7

The agricultural use of chlorothalonil in the lower 48 states is shown in Figure 3. The map was 

prepared by BEAD based on private market surveys (proprietary source) of pesticide use in 

 

6

 Yourman, L.; Alsadek, J.; Ranville, M.; BEAD Chemical Profile for Registration Review: Chlorothalonil (089101) 

Oct. 25, 2011 

7

 USDA-NASS 2001-2008; private pesticide market research 2001-2008; and California Department of Pesticide 

Regulation 2000-2009. 
12 

agriculture for 2006-2010 at the Crop Reporting District (CRD) level.8

 CRDs are boundaries 

created by USDA NASS which are aggregates of counties.9

 The map reveals intensive 

agricultural use in Michigan, Maine, Long Island (New York) and the Southeast (Florida, 

Georgia and Mississippi). The states with the most agricultural usage were on average Georgia 

(25%), Florida (13%), California (9%), Michigan (8%) and Alabama (7%). The survey data are 

limited to the states that represent the top 80-90% of acreage for the individual crops; therefore, 

use may be occurring in regions outside the scope of the survey. Pesticide usage is displayed as 

average pounds (for the years 2006-2010) per 1,000 acres of farmland in a CRD to normalize for 

the variation in farmland between CRDs. Farmland acreage was obtained from USDA.10 The 

map is an illustration of a snapshot in time of chlorothalonil use for agricultural purposes and 

does not include non-agricultural uses. 

Figure 3. Agricultural Use Pattern Summary for Chlorothalonil 

Conventional Non-Agricultural Uses

Non-agricultural use sites include golf courses, lawns around commercial and industrial 

buildings, and other turfgrass such as professional and collegiate athletic fields. Chlorothalonil is 

also registered for home garden use on fruit and vegetables. Of these uses, chlorothalonil use is 

highest on golf courses, at approximately three million pounds per year. A large amount of 

chlorothalonil is also used by consumers (i.e., residential use). On average consumers use 

 

8

 Kaul, M. Chlorothalonil Usage Map by Crop Reporting District, October 26, 2011 (via email) 9

 USDA, 2006-2010. NASS Crop Reporting Districts. Online: 

http://www.ers.usda.gov/briefing/arms/resourceregions/resourceregions.htm#nass. 10 USDA, 2007. Census of Agriculture. Online: http://www.agcensus.usda.gov/Publications/2007/index.asp. 
13 

approximately one million pounds of chlorothalonil per year. Usage data for 2002, 2004 and 

2006 suggest the use of chlorothalonil is increasing on institutional turf while nursery and 

greenhouse use is going down. In total, the average yearly non-agricultural use of chlorothalonil 

is approximately 4.5 million pounds per year. This statistic also includes turf farms which for 

analysis purposes were considered non-agricultural use. 

Antimicrobial Non-Agricultural Uses

Chlorothalonil is used as a material preservative for wood products used in making wood 

composites. It is mixed into wood stains, paints, and coatings; exterior aqueous- and solventbased paints, stains, and coatings as film preservatives and mixed into aqueous-based adhesives, 

stucco, grouts and joint compounds, aqueous-based caulks and sealants as an antimildew/ 

antimold surface protectant. It is also used as an industrial wood preservative both as an additive 

to dip, spray, and pressure treatment solutions and independently as a sapstain preventative in 

freshly sawn lumber and timber as well as mold control on previously pressure treated wood 

products. The pressure treatment use of chlorothalonil is carried along with previously registered 

chromate copper arsenate (CCA) mixture solution. Industrial scale wood preservative is applied 

by dipping, spraying or pressure treatment. Treated wood types includes timber, utility poles, 

crossarms, crossties, posts, pilings, construction timbers, lumber and wood products such as 

particle board, fencing, decking, building siding, and shingles. Chlorothalonil is also mixed or 

blended into a variety of materials (e.g., paints, stains, stucco, adhesives, caulk) using a variety 

of methods depending upon the material. For the most part these are blended at the industrial or 

manufacturing scale, the exception is post-manufacturing paint additive products. There are 

wood preservative stains and coatings for use by professionals or the public which can be hand 

spray, brush or pad applied. Similarly there are exterior and interior film preservatives (paints, 

stains and coatings) which can be applied to a variety of surface materials including wood, metal, 

masonry, and concrete by professionals or the public by hand spray, brush or pad. The pressure 

treatment use of chlorothalonil is carried along with previously registered chromate copper 

arsenate (CCA) mixture solution. 

Label Application Rates and Intervals 

Chlorothalonil labels may be categorized into two types: labels for manufacturing uses 

(including technical grade chlorothalonil and its formulated products) and end-use products. 

While technical products are not used directly in the environment, they are used to make 

formulated products. A complete list of all current conventional chlorothalonil uses and how 

EFED currently understands them, including the uncertainties for which reasonable conservative 

assumptions will be made in the absence of additional label information, are listed in Table 4. 

Table 5 summarizes the antimicrobial registrations of chlorothalonil as currently understood by 

AD. 

For some uses, there are different label restrictions for agricultural and non-agricultural use 

labels for the same crop; these differences are also highlighted in Table 4 as appropriate. The 

final risk assessment will be based on the labeled uses (maximum single and yearly application 

rates and minimum retreatment intervals) at the time the assessment is conducted and are 

considered part of the federal action reflecting the current labeled uses of chlorothalonil. 
14 

Table 4. Chlorothalonil Conventional Pesticide Use Label Summary* 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

ALMOND:air/ground Hull split, petal fall, popcorn to full bloom, postharvest, bud break, foliar 

3.0 18.8 NS [61 ] NS [32] 

- If 6 applications at 3.0 ladditional application of 0made in that year to reach annual maximum applicat- Geographic disallowabl- 150 day(s) preharvest in- 42 day(s) preharvest int

APRICOT: air/ground Hull split, petal fall, popcorn to full bloom, postharvest, bud break, foliar, delayed dormant, dormant, established plantings, late fall, pink through petal fall, popcorn NS [3.14] NS [15.5] NS [51] NS [10] 

- The application informa- For ECHO® RTU (EPA label does not specify a siapplication rate for the folnectarine, apricot, cherry, application rate for these u- “Apply full coverage sprto thoroughly cover tree cundersides of leaves.” - Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int

ASPARAGUS: air/GroundEarly bloom, post-final harvest, postharvest 

3.0 9.0 NS [31] 14 

- Buffer zone restriction. - Geographic disallowabl- 120 day(s) preharvest i- 190 day(s) preharvest i

BANANA: air/ground (not specified); foliar 

2.7 30.0 NS [111] 10 

- If 11applications at 2.7 additional application of 0made in that year to reach annual maximum applicat

- Geographic allowable: P- Max application rate is cycle (not per year) 

BEANS, DRIED-TYPE: 1.5 6.0 NS [41] 7 - Buffer zone restriction. 
15 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/ chemigation /groundEarly bloom through foliar, Early bloom, Foliar 

- Geographic disallowabl- 14 day(s) preharvest int- 42 day(s) preharvest int

BEANS, SUCCULENT (SNAP): air/groundEarly bloom through foliar 2.3 9.0 NS [41] 7 

- If 4 applications at 2.3 lwould result in 0.2 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 2.5 lb/a (residential) 60- 7 day(s) preharvest inte

BEANS: air/ground (not specified) Early bloom, when needed 

0.2034 0.2034 NS [11] 7 

- Max application rate is per year. - 7 day(s) preharvest inte

BULB VEGETABLES: air/chemigation/groundFoliar 1.2 5.0 NS [41] 7 

- If 4 applications at 1.2 ladditional application of 0made in that year to reach maximum application rate

BLUEBERRY:air/groundAt bud break, Delayed dormant, Post-final harvest, Postharvest 

3.0 9.0 NS [31] 10 

- Buffer zone restriction. - Geographic allowable: F- Geographic disallowabl- 42 day(s) preharvest int

BRASSICA (HEAD AND STEM): air/chemigation/ground Foliar, Postemergence, Posttransplant, Transplant, When needed

1.5 8.8 NS [61] 

7 

- Labels differ on the maxmaximum annual applicattherefore, rates associated and maximum annual app- If 6 applications at 1.5 l

would result in 0.2 lb a.i./a.i./acre annual maximum 

1.1 10.5 NS [91] 

BROCCOLI, CHINESE: air/chemigation/groundFoliar, Postemergence, Transplant 

1.5 12.0 NS [81] 7 

- Buffer zone restriction. - 7 day(s) preharvest inte

BROCCOLI: 1.5 12.0 NS [81] 7 - 7 day(s) preharvest inte
16 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/groundFoliar, Postemergence, Posttransplant, Transplant, When needed BRUSSELS SPROUTS: air/chemigation/groundFoliar, Postemergence, Posttransplant, Sprout, Transplant, When needed 

1.5 12.0 NS [81] 7 

- Buffer zone restriction. - Geographic allowable: Postemergence) - 0 day(s) preharvest inte- 7 day(s) preharvest inte

CABBAGE, CHINESE: air/chemigation/groundFoliar, Postemergence, Posttransplant, Transplant, When needed Foliar 

1.5 12.0 NS [81] 7 

- Buffer zone restriction. - 7 day(s) preharvest inte

CABBAGE: air/chemigation/groundFoliar, Postemergence, Posttransplant, Transplant, When needed 

1.5 12 NS [81] 7 

- Buffer zone restriction. - 7 day(s) preharvest inte

CARROT (INCLUDING TOPS): air/chemigation/groundFoliar, When needed 

1.5 15 NS [101] 7 

- Geographic disallowabl- 0 day(s) preharvest inte- 7 day(s) preharvest inte

CAULIFLOWER: air/chemigation/groundFoliar, Postemergence, Posttransplant, Transplant, When needed 

1.5 12 NS [81] 7 

- Buffer zone restriction. - 7 day(s) preharvest inte

CELERY: 2.3 18.0 NS [81] 3 - If 8 applications at 2.3 l
17 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/groundAt planting, Foliar, Postemergence, Posttransplant, Seed bed, Transplant 

would result in 0.4 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 7 day(s) preharvest inte

CHERRY: air/ground Bloom, Delayed dormant, Dormant, Established plantings, Foliar, Pink through petal fall, Popcorn to full bloom, Popcorn, Postharvest 

NS [4.2] NS [15.5] NS [31] 7 

- Not all of the labels for single or max annual applthe label for ECHO® RTU 30) does not specify a sinapplication rate for the folnectarine, apricot, cherry, application rate for these u- “Apply full coverage sprto thoroughly cover tree cundersides of leaves.” - If 3 applications at 4.2 ladditional application of 2made in that year to reach annual maximum applicat

- Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int

CHRISTMAS TREE PLANTATIONS: air/ground Nurserystock, Before budbreak, After bud break, 

4.2 

16.5 

NS [41] 

NS [32] 

- If 3 applications at 4.5 ladditional application of 3made in that year to reach annual maximum applicat

4.5 NS [31] 

COLE CROPS: air/chemigation/ground Foliar

1.0 12.0 NS [121] 17 

- No comment 

COMMERCIAL/INDUSTRIAL 11 26.0 NS [21] NS [32] - If 2 applications at 11 lb 
18 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

LAWNS: chemigation/ground foliar, late fall, fall, at seeding, late winter

additional application of 4made in that year to reach maximum application rate

CONIFERS (PLANTATIONS/NURSERIES): air/chemigation/ground Nurserystock, Before budbreak, After bud break, Spring, Seed bed

4.5 16.5 NS [31] NS [32] 

- If 3 applications at 4.5 ladditional application of 3made in that year to reach annual maximum applicat

CORN (UNSPECIFIED): air/ground Foliar, Seed crop 

1.5 9 NS [61] 7 

- Application information - Buffer zone restriction. - 14 day(s) preharvest int

CORN, SWEET: air/ground Foliar, Seed crop, When needed 

1.5 9.0 NS [61] 

7 

4 (for as needed 

low rate) 

- Buffer zone restriction. - 14 day(s) preharvest int- 7 day(s) preharvest inte

CRANBERRY: air/chemigation/groundEarly bloom through foliar, Early bloom, Foliar, Prebloom 5.3 15.1 NS [31] 10 

- If 3 applications at 5.3 would result in 0.8 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - Geographic disallowabl- 50 day(s) preharvest int

CUCUMBER: air/chemigation/groundAt vine formation, Foliar, When needed 

6.3 (vine 

formation) 

15.8 

NS [21] 

7 

- If 2 applications at 6.3 ladditional application of 3made in that year to reach annual maximum applicat- If 7 applications at 2.3 lwould result in 0.3 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 0 day(s) preharvest inte- 7 day(s) preharvest inte

2.3 (foliar) NS [71] 

CUCURBIT VEGETABLES: 2.3 15.8 NS [71] 5 - If 7 applications at 2.3 l
19 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/ground Foliar

would result in 0.3 lb a.i./a.i./acre annual maximum 

FILBERT (HAZELNUT): air/ground At bud break, Delayed dormant, Foliar, Popcorn 3.6 9 NS [21] 14 

- If 2 applications at 3.6 ladditional application of 1made in that year to reach maximum application rate- Buffer zone restriction. - Geographic allowable: - 120 day(s) preharvest in

FOREST TREES (SOFTWOODS, CONIFERS): Nurserystock, Before budbreak, After bud break, Spring, Seed bed

4.5 16.5 NS [41] NS [32] 

- Not all of the labels for minimum application inte- If 4 applications at 4.5 lwould result in 1.5 lb a.i./a.i./acre annual maximum 

FRUITING VEGETABLES: air/chemigation/ground Foliar 

2.3 18.0 NS [81] 7 

- If 3 applications at 2.3 lwould result in 0.4 lb a.i./a.i./acre annual maximum 

GARBANZOS (INCLUDING CHICK PEAS): air/ chemigation /groundFoliar 

1.5 6.0 NS [41] 7 

- WA020022 does not limapplication rate or the num

GARBANZOS (INCLUDING CHICK PEAS): air/chemigation/groundFoliar 

1.5 6.0 NS [41] 7 

- Do not make more than cycle. - Geographic allowable: N- 14 day(s) preharvest int

GARLIC : 2.3 15.1 NS [61] 7 - If 6 applications at 2.3 l
20 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/groundFoliar, Seed crop, When needed 

additional application of 1made in that year to reach annual maximum applicat- Buffer zone restriction. - Foliar and Seed Crop: G- Grown for seed only. - 7 day(s) preharvest inte

GINSENG (MEDICINAL): air/chemigation/ground Foliar

NS [1.5] NS [21] NS [141] 7 

- Not all of the labels for single or max annual appl

GOLF COURSE: 6.25 25 NS [41] 7 - No comment GRASS FORAGE/FODDER/HAY: air/ground Foliar, Seed crop 

1.6 4.5 NS [31] 14 

- If 3 applications at 1.6 would result in 0.3 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 14 day(s) preharvest int

GRASSES GROWN FOR SEED : air/chemigation/groundInternode elongation 

1.5 4.5 NS [31] 14 

- 14 day(s) preharvest int

HORSERADISH: air/chemigation/ground Foliar 2.2 18.0 NS [81] 7 

- If 8 applications at 2.2 ladditional application of 0made in that year to reach annual maximum applicat

LEEK: air/chemigation/groundFoliar, When needed 2.3 6.8 NS [31] 7 

- Buffer zone restriction. - Do not make more than cycle. - 14 day(s) preharvest int - 7 day(s) preharvest inte

LENTILS: 1.1 6.0 NS [51] 7 - If 5 applications at 1.1 l
21 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/ground Foliar

additional application of 0made in that year to reach maximum application rate

LUPINE, GRAIN: air/chemigation/ground Foliar 1.1 6.0 NS [51] 7 

- If 5 applications at 1.1 ladditional application of 0made in that year to reach maximum application rate

MANGO: air/ground At bud break, Early bloom through foliar, Early bloom, Popcorn 

2.6 24 NS [91] 7 

- If 9 applications at 2.6 ladditional application of 0made in that year to reach annual maximum applicat

- 21 day(s) preharvest int

MELONS: air/chemigation/ground At vine formation, Foliar

6.3 (vine 

formation) 

15.8 

NS [21] 

7 

- If 2 applications at 6.3 ladditional application of 3made in that year to reach annual maximum applicat- If 7 applications at 2.3 lwould result in 0.3 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 0 day(s) preharvest inte- 7 day(s) preharvest inte

2.3 (foliar) NS [71] 

MINT/PEPPERMINT/ SPEARMINT: air/chemigation/ground Foliar 

1.1 3.0 NS [31] 7 

- If 3 applications at 1.1 lwould result in 0.3 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - Geographic allowable: - 80 day(s) preharvest int

MINT: 1.1 3.0 NS [31] 7 - If 3 applications at 1.1 l
22 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/ground Foliar 

would result in 0.3 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - Geographic allowable: - 80 day(s) preharvest int

MUSHROOMS: chemigation/groundAfter spawning, Plant bed 11.5 NS [23] 2 NS [32] 

- The maximum number max annual application racycles not per year. - 5 day(s) preharvest inte

NECTARINE: air/ground Before bud break, Bloom, Delayed dormant, Dormant, Established plantings, Foliar, Late fall, Petal fall through foliar, Petal fall, Pink through petal fall, Popcorn to full bloom, Popcorn, Postharvest 3.1 15.5 NS [51] 10 

- For ECHO® RTU (EPA label does not specify a siapplication rate for the folnectarine, apricot, cherry, application rate for these u- “Apply full coverage sprto thoroughly cover tree cundersides of leaves.” - Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest in- Preharvest interval not l

ONION: air/chemigation/ground Foliar, In storage, Seed crop, When needed 

2.2 15 NS [71] 7 - If 7 applications at 2.2 l

would result in 0.4 lb a.i./a.i./acre annual maximum - Buffer zone restriction. - 7 day(s) preharvest inte

6.8 (seed) 6.83 NS [33] Not applicable3

ONIONS (GREEN): 2.3 6.8 3 7 - Buffer zone restriction. 
23 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/ground foliar, When needed 

- Do not make more than cycle. - 14 day(s) preharvest int - 7 day(s) preharvest inte

ORNAMENTALS (LAWNS, TURF, SOD FARMS) : air/chemigation/ground 

13.0 

(chemigation 

and ground) 

27.0 

NS [21] 

NS [32] 

- If 2 applications at 13.0 additional application of 1made to reach the 27.0 lb application rate. - If 2 applications at 11.4 additional application of 4made to reach the 27.0 lb application rate. 

11.4 NS [21] 

ORNAMENTALS (PLANTS AND TREES): air/chemigation/ground 

NS [1.5] NS [36.36] NS [241] NS [7] 

- The application informaall of the labels for this usannual application rate or application interval. - If 24 applications at 1.5 additional application of 0made in that year to reach annual maximum applicat

Other 

PAPAYA: ground Foliar 3.0 6.8 3 14 

- Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int- 14 day(s) preharvest int

PARSNIP: air/chemigation/ground Foliar 

1.6 6.0 4 7 

- Buffer zone restriction. - Geographic disallowabl- 10 day(s) preharvest int

PASSION FRUIT 2.2 7.6 NS [31] 14 - If 3 applications at 2.2 l
24 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

(GRANADILLA): ground Bloom through foliar, Bloom, Foliar,

additional application of 1made in that year to reach maximum application rate- Buffer zone restriction. - Geographic allowable: H- 7 day(s) preharvest inte

PEACH: air/ground Before bud break, Bloom, Dormant, Established plantings, Foliar, Late fall, Delayed dormant , Petal fall through foliar, Petal fall, Pink through petal fall, Popcorn to full bloom, Popcorn, Postharvest 

3.1 15.5 NS [51] 10 

- For ECHO® RTU (EPA label does not specify a siapplication rate for the folnectarine, apricot, cherry, application rate for these u- “Apply full coverage sprto thoroughly cover tree cundersides of leaves.” - Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int

PEANUTS (UNSPECIFIED): air/chemigation/ground Foliar, Postplant, 

1.2 

9.0 

NS [71] 10 

- If 7 applications at 1.2 ladditional application of 0made in that year to reach maximum application rate- Buffer zone restriction. - Do not apply through ansystem. - Do not make more than cycle. - 14 day(s) preharvest int- Postplant: 120 months restriction. 

0.75 

(postplant) 4 (postplant) 14 (postplant) 

PISTACHIO: air/ground Bloom 

4.5 22.5 NS [51] 28 

- 14 day(s) preharvest int - 42 day(s) preharvest in

PLANTAIN: 2.7 30.0 NS [111] 10 - If 11applications at 2.7 
25 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/ground Foliar

additional application of 0made in that year to reach annual maximum applicat

- Geographic allowable: P- Max application rate is cycle (not per year) 

PLUM: air/ground Bloom, Delayed dormant, Dormant, Established Plantings, Foliar, Pink through petal fall, Popcorn to full bloom, Popcorn 

3.13 15.53 NS [51] 10 

- Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int

POTATO, WHITE/IRISH: air/chemigation/ground At vine formation, Foliar, When needed 

1.4 

NS [4.2 (except 

in FL); 5.6 (in 

FL)] 

NS [3 (except 

in FL); 4 (in 

FL)] 

5 

- The max annual applicaof applications is not provfor this use. - The max annual applica81. - Buffer zone restriction. - Geographic allowable: - 5 day(s) preharvest inte- 7 day(s) preharvest inte

PRUNE: air/ground Bloom, Delayed dormant, Dormant, Established Plantings, Foliar, Pink through petal fall, Popcorn to full bloom, Popcorn 3.1 15.5 NS [51] 10 

- For ECHO® RTU (EPA label does not specify a siapplication rate for the folnectarine, apricot, cherry, application rate for these u- “Apply full coverage sprto thoroughly cover tree cundersides of leaves.” - Buffer zone restriction. - Geographic disallowabl- 00 day(s) preharvest int

PUMPKIN: 1.36 15.75 NS [111] 10 - If 11 applications at 1.3
26 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/ground Foliar, When needed 

an additional application obe made in that year to reannual maximum applicat- Buffer zone restriction. - 0 day(s) preharvest inte- 7 day(s) preharvest inte

ROSE: ground Foliar 1.1 NS [27] NS [27] 7 

- The application informall of the labels for this usapplication rate or max nuallowed/year. 

SHALLOT: air/chemigation/ground Foliar, When needed 2.2 6.7 NS [31] 7 

- Do not make more than cycle. - 14 day(s) preharvest int - 7 day(s) preharvest inte

SOYBEANS (UNSPECIFIED): air/chemigation/ground At emergence through seedling stage, At emergence, Bloom through foliar, Early bloom through foliar, Foliar, Postemergence 

1.9 4.5 NS [21] NS [14] 

- If 2 applications at 1.9 ladditional application of 0made in that year to reach maximum application rate- The application interval the labels for this use. - Buffer zone restriction. - Geographic disallowabl- 42 day(s) preharvest int

SQUASH (ALL OR UNSPECIFIED): air/chemigation/ground Foliar, When needed 1.36 15.75 NS [111] 10 

- If 11 applications at 1.3an additional application obe made in that year to reannual maximum applicat

- Buffer zone restriction. - 0 day(s) preharvest inte- 7 day(s) preharvest inte

STONE FRUITS: NS [4.2] NS [15.5] NS [31] 7 - Not all of the labels for 
27 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

ns At bud break, Hull split, Pink through petal fall, Popcorn

single or max annual appl- If 3 applications at 4.2 ladditional application of 2made in that year to reach annual maximum applicat- Buffer zone restriction. - 00 day(s) preharvest int

STRAWBERRY: air/chemigation/ground Nonbearing nursery stock, Preplant 

1.1 15 NS [141] NS [10] 

- Geographic allowable: - Nonbearing Nursery Sto- Tank dip (no retreatmenCA960027) - If 14 applications at 1.1 would result in 0.4 lb a.i./a.i./acre annual maximum 

SUGAR BEET: air/chemigation/ground October 

1.3 NS [36.4 – see comments] NS [28 – see comments] NS [32] 

- Geographic allowable: OR990039 - The max annual applicatapplications allowed per yapplication interval are nothis use; therefore, the mathat can be modeled (for aassumed. 

TOMATO: air/chemigation/ground Foliar, Fruiting, When needed 

2.3 15.1 NS [61] 7 

- If 6 applications at 2.3 ladditional application of 1made in that year to reach annual maximum applicat

- Buffer zone restriction. - Geographic disallowabl- 0 day(s) preharvest inte- 7 day(s) preharvest inte

YAM: 0.9 11.2 NS [121] 10 - If 12 applications at 0.9 
28 

Use: 

Method 

Timing 

(For Any Registration Number)

LIMITATIONS

Maximum 

Single 

Application

 Rate (lb 

a.i./acre) 

Maximum 

Yearly 

Application 

Rate (lb 

a.i./acre) 

Maximum 

Number of 

Applications

Per Year 

Minimum 

Retreatment 

Interval (days) 

Com

air/chemigation/ground Foliar 

additional application of 0made in that year to reach annual maximum applicat

* Table reflects current labels as of December 23, 2011. The bracketed information represents the assumptions that will be made for risk assessment purposes in the absence of additional lab

NS = ‘not specified’ on at least one of the labels for that use site. 

1. The maximum number of applications/year was calculated by dividing the maximum annual application rate by the single max

allowed on the label. If the single max application cannot be evenly divided into the max application rate, it is indicated this in This implies that the use may not be modeled by simply multiplying the number of applications by the maximum single applic

2. A 3-day reapplication interval is assumed based on the shortest retreatment interval allowed on any label for any chlorothaloni3. Since this is a seed treatment use only one application is assumed per season; however, since onions specifically green onions 

times per year in some locations the number of applications per year is assumed to be three.11 This assumes that the label that 

also include onion (green onion) limitations. 

11 Kaul, M. Maximum Number of Crop Cycles Per Year in California for Methomyl Use Sites. Date February 28, 2001. 
29 

Table 5. Chlorothalonil Antimicrobial Pesticide Use Label Summary 

Use1 Method of Application Application Rate Maximum Concentration of a.i. in Treated Material 

Industrial wood preservative (timber, lumber, utility poles, crossarms, crossties) and sapstain 

Dip tank, brush, 

spray 2,486 to 23,797 ppm a.i. Retention rate in lbs a.i./ft3 is not provided 

Pressure treatment At retention level of 0.3 to 0.8 a.i lbs ft3 0.8 lbs a.i. per ft3 of wood 

Material preservative—wood composites 

Various methods are 

used to mix 1.25-12.5 lbs a.i./ft3 12.5 lbs a.i./ft3

Industrial preparation of over-thecounter wood preservative paints, stains, and coatings (siding, fences, decks, planking, shingles, shakes, wood furniture) 

Various industrial 

methods are used to 

mix and blend 

 13,950 ppm 

Tresprato esurf

Industrial preparation of over-thecounter antifungal/antimold paints, stains, and coating for use on metal, masonary, etc. (Film preservative) 

Various industrial 

methods are used to 

mix and blend 

13,950 ppm exterior 

9,799 ppm interior 

Tresprato esurfmet

Material preservative—stucco 

Various industrial 

methods are used to 

mix and blend 

No application rate to exterior 

surfaces provided 

Material preservative—aqueousbased adhesives, caulks & sealants Various industrial methods are used to mix and blend No application rate to exterior surfaces provided 11,750 ppm No 

outd

Material preservative—Paper/paper board (non-food contact) 

Various industrial 

methods are used to 

mix and blend 

No application rate provided 1,415 ppm 

lbs a.i./ft3: pounds of active ingredient per cubic foot ppm: parts per million or milligram per kilogram (mg/kg) 
30 

D. ENVIRONMENTAL FATE AND TRANSPORT

Chlorothalonil Fate Properties

Environmental fate properties of chlorothalonil are summarized in Table 6. The fate dataset has 

major deficiencies. No fate studies are classified as acceptable with the exception of two BCF 

studies. Based on supplemental information, chlorothalonil was shown to undergo a number of 

different chemical reactions including de-chlorination, hydroxylation and sulfonation in the 

environment to form a number of different transformation products. All the transformation 

products reported retain the phenyl ring with the exception of carbon dioxide (CO2). Maximum 

concentration of each transformation product formed is provided in Table 7. In summary, 

laboratory studies indicate chlorothalonil will transform primarily through aqueous photolysis in 

clear, shallow water. Chlorothalonil is also susceptible to microbial-mediated transformation, 

with transformation rates often departing from first-order kinetics. Degradation rates have been 

shown to be dependent on the application rate with higher chlorothalonil application rates 

resulting in slower degradation rates and vice versa. Data also suggest that chlorothalonil is 

rapidly transformed in water/sediment systems under both aerobic and anaerobic conditions. 

Field dissipation studies show that chlorothalonil dissipates (e.g., transformation or relocation) 

with half-lives less than 100 days; however, in a few field dissipation studies chlorothalonil was 

observed in soil samples taken after one year. Batch equilibrium data suggest chlorothalonil is 

slightly to hardly mobile in soil systems. A summary of submitted environmental fate studies is 

provided in APPENDIX A. A detailed discussion of each of the relevant environmental fate 

studies is provided in the subsections below. 

Table 6. Environmental Fate Parameters of Chlorothalonil 

Parameter Value Source 

Classification; Comments

Abiotic Transformation Mechanisms

Hydrolysis Half-life No substantial degradation 

(pH 5 and 7) 

MRID 00040539 

Supplemental 

 Some aspects of the study are invalid 

(i.e., pH 9). Transformation of 

chlorothalonil was observed at pH 9; 

however, a mass balance was not 

provided and degradation products were 

only analyzed in one sample (day 89). 

Additional data are needed to assess the 

transformation of chlorothalonil under 

basic conditions (pH >9). 

Soil Photolysis Half-life 

No substantial degradation MRID 00087349 

Supplemental 

No substantial degradation MRID 00040543 

Supplemental 

Aqueous Photolysis 

half-life 

10.3 hours 

pH 7, 30 °North 

MRID 45710223 

Supplemental3 

Biotic Transformation Mechanisms1

Aerobic Soil 

Metabolism Half-life 

58 days (SFO)/ 127 days (DFOP) 

STERILE CONTROL: 105 days (SFO) 

39 mg/kg (~78 lb/a2

); Illinois silty clay loam 

(pH 5.1 1.3% OC) 

MRID 00087351 

MRID 00040547 

Supplemental 
31 

Parameter Value Source 

Classification; Comments

15 days (SFO)/ 23 days (IORE) 

STERILE CONTROL: 32 days (SFO) 

39 mg/kg (~78 lb/a2); Iowa loam (pH 7.0 4.2% 

OC) 

These two MRIDs are the same study. 

A substantial amount of chlorothalonil 

transformation is observed in the sterile 

controls; and a material balance could not 

be determined because unextracted 

residues were not measured directly. 

14 days (SFO)/ 23 days (IORE) 

STERILE CONTROL: 33 days (IORE) 

39 mg/kg (78 lb/a2); Texas sandy loam (pH 8.0 

0.9% OC) 

10 days (SFO)/ 16 days (IORE) 

STERILE CONTROL: 33 days (SFO) 

3.9 mg/kg (8 lb/a2); Ohio sandy loam (pH 6.0 

1.9% OC) 

5.4 days (SFO)/ 18 days (IORE) 

1 mg/kg, 1.7 lb/a2

; Ohio loamy sand (pH 5.1, 

1.5% OC, 2.6 %OM, 7.1, 7.0 CEC) MRID 43879601 

21.3 days (SFO)/ 34.8 days (IORE) Supplemental 

10 mg/kg (20 lb/a2); Ohio loamy sand (pH 5.1, 

1.5% OC, 2.6 %OM, 7.1, 7.0 CEC) 

0.5 days (SFO)/0.3 days (IORE) 

0.1 mg/kg (0.2 lb/a2

); 18 acres (not reported) 

MRID 47207702 

Supplemental 

No data are provided for day 0 (assumed 

to be 100%), for this reason, 

chlorothalonil concentration at day 0 was 

assumed to be 100% of the applied 

radioactivity; soil characterization was not 

provided; duplicate samples were not 

analyzed; and no soil controls were 

provided. 

3 days (SFO)/ 18 days (IORE) 

1 mg/kg (2 lb/a2); 18 acres (not reported) 

10 days (SFO) 

10 mg/kg (20 lb/a2

); 18 acres (not reported) 

18 days (SFO)/ 243 days (IORE) 

25 mg/kg (50 lb/a2

); 18 acres (not reported) 

1 day (SFO)/ 1.5 days (IORE) 

1.5 kg/ha; 1.3 lb/a; 18 acres (pH 5.4, 4.5% OC, 

4.5 %OM, 16.2 CEC) MRID 47207703 

Supplemental 

Application rates are not reflective of 

current maximum label rates and 

transformation of chlorothalonil has been 

shown to be concentration dependent. 

0.3 days (SFO)/ 0.5 days (IORE) 

1.5 kg/ha; 1.3 lb/a; Chamberlain’s Farm (pH 

6.8, 3.2% OC, 3.2% OM, 8.0 CEC) 

1.3 days (SFO)/ 1.7 days (IORE) 

1.5 kg/ha; 1.3 lb/a; ERTC (pH 5.0, 1.3% OC, 

1.3% OM, 4.4 CEC) 

2.4 days (SFO)/ 4.1 days (IORE) 

1.5 kg/ha; 1.3 lb/a; Munster (pH 4.8, 2.5% OC, 

2.5% OM, 5.5 CEC) 

Anaerobic Soil 

Metabolism Half-life no data available 

Aerobic Aquatic 

Metabolism Half-life 

3.4 days (SFO)/ 8.5 days (IORE) 

Bury Pond [pH 5.2 (water) 8.0 (sediment), 1% 

OC, 16 CEC)], 

The concentrations varied substantially 

throughout the study. 

MRID 45908001 

Supplemental 

The stability of the parent and its 

transformation products during storage 

prior to analysis were not addressed; 

volatile transformation products were 

detected at ≥10% AR but not identified; 

and there is also a large amount of 

unidentified HPLC residues. 

0.1 day (SFO)/1.1days (IORE) 

Houghton Meadow [pH 6.73 (water) 7.3 

(sediment), 5.8% OC, 51.4 CEC)] 
32 

Parameter Value Source 

Classification; Comments

0.06 days (SFO)/ 0.1 days (IORE) 

0.6 mg/L; Ohio and DI water (pH 6.8) 

MRID 42226101 

Supplemental 

Studies were not conducted with natural 

water. 

0.3 days (SFO)/ 1.9 days (DFOP) 

0.6 mg/L; Virginia with artificial sea water (pH 

9.3) 

2.6 days (SFO)2

Emperor Lake (pH 7.4) 

MRID 47207701 

Supplemental 

Establishment of chlorothalonil 

transformation profile could not be 

determined; analytical methods were not 

suitable for isolating individual 

compounds; and not all major 

transformation products were identified. 

0.8 days (SFO)2 

Bury Pond (pH 7.9) 

Anaerobic Aquatic 

Metabolism Half-life 

10.6 days (SFO) 

Tennessee silt loam (pH 6.0-7.2, 8.4-10.4 

CEC) 

MRID 00147975 

Supplemental 

No data are provided for day 0 (assumed 

to be 100%), for this reason, 

chlorothalonil concentration at day 0 was 

assumed to be 100% of the applied 

radioactivity; for one test system the study 

was terminated before the pattern of 

dissipation of some of the major 

transformation products was established; 

distilled water was used instead of natural 

water and soil rather than sediment was 

used in this study; and although the test 

system was kept on nitrogen (30 days 

prior to study initiation) redox potentials 

and oxygen concentrations were not 

provided during the experiment so it 

cannot be determined that the test systems 

was anaerobic. 

9.7 days (SFO)/ 21.5 days (IORE) 

Ohio sandy loam (pH 5.7-6.0, 112.0-12.6 

CEC) 

Mobility

Range of Freundlich 

soil-water partition 

coefficients (KF); 

exponent (1/n) values; 

and 

organic carbonnormalized coefficients 

(KFOC) 

12, 14, 19, 56, 131, and 500 L/kg-soil; 

0.66, 0.66, 0.72, 0.91, 1.1, and 1.2; and 

1121, 2039, 2958, 5085, 6605, and 11935 

mL/gOC 

MRID 00029406 

Supplemental 

The temperature and the light conditions 

used in the definitive study were not 

reported; a desorption phase was not 

conducted; and material balance was not 

determined. 
33 

Parameter Value Source 

Classification; Comments

Field Dissipation 

Terrestrial Field 

Dissipation Half-life 

58, 56, 74, and 81 days* 

00071625 

Supplemental 

*Sampling intervals were inadequate to 

define the half-life under field conditions. 

A storage stability study was not 

conducted. The pattern of formation and 

decline of the transformation products 

could not be determined. And the 

sampling depth was not sufficient to 

define leaching. 

33, 46, 50, 58, and 74 days* 

MRIDs 00071627, 00087369, 00087332, 

and 00087301 

Supplemental 

*Sampling intervals were inadequate to 

define the half-life under field conditions 

Analytical methods were inadequate in 

identifying transformation products of 

chlorothalonil. 

Bioaccumulation 

Fish BCF 

edible, non-edible, and 

whole fish tissues 

256, 5812 and 3077 

at initial water exposure level of 0.1 μg/L 

chlorothalonil 

MRID 45710224 

Acceptable 

Chlorothalonil concentration in water 

during the exposure ranged from 39-97%.

No data was provided on the depuration 

rates in this study. 

306, 5694 and 3041 

at initial water exposure level 0.5 μg/L 

chlorothalonil 

Oyster BCF 

whole oyster 

2660 (total residue primarily of transformation 

products) 

MRID 43070601 

Acceptable 

1. Representative half-life values were calculated using the draft NAFTA degradation kinetics document: 

Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media (draft document June 

29, 2011); Single First Order (SFO), Nth-Order Rate Model or Indeterminate Order Rate Equation Model 

(IORE), and Double First-Order in Parallel (DFOP) 

2. SFO kinetic analysis was the only method employed. 

3. Aquatic photolysis study was reclassified to supplemental as all major transformation products were not 

adequately identified. Additional data are needed to identify all major transformation products or other 

residues of potential toxicological concern. 

Applied Radioactivity (AR) 

BCF: bioconcentration factor 

Cation Exchange Capacity (CEC) 

DI: deionized water 

lb/a2

: pound per square acre 

mg/kg: milligrams per kilogram 

mL/gOC: milliliters per gram of organic carbon 

Organic Carbon (OC) 

OM: organic matter 

pH: One divided by the log of the hydrogen ion concentration 
34 

Table 7. Maximum Observed Concentrations of Chlorothalonil Transformation Products in EnvironmentStudies 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

Major (>10%) Transformation Products 

SDS-3701 

DCA-3701 

DS-3701 

R182281 

CNIL/02

4-hydroxy-2,5,6-trichloro-1,3-

dicyanobenzene 

C1(=C(C(=C(C(=C1Cl)C#N)O

[H])Cl)Cl)C#N 

Aquatic Photolysis 

835.2240 

45121803 

Supplemental2 

Aerobic Soil 

Metabolism 

835.4100 

00040547 00087351 

Supplemental 

Aerobic Aquatic 

Metabolism 

835.4300 

45908001 

Supplemental 

Hydroxy-chloro-1,3-

dicyanobenzene (unspecified 

number of attached atoms (1-3) 

N

N Clx OHx

Aquatic Photolysis 

835.2240 

45121803 

Supplemental2 

SDS-47523 

R611966 

CNIL/05 

3-cyano-2,4,5-

trichlorobenzamide 

C1(=C(C(=CC(=C1Cl)C(=O)N

([H])[H])Cl)Cl)C#N CONH2

N

Cl

ClCl

Aerobic Soil 

Metabolism 

835.4100

43879601 

Supplemental3 

SDS-46851 3-carbamoyl-2,4,5- Aerobic Soil 43879601 

Cl

Cl OH

Cl

N

N
35 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

R611965 

CNIL/04 

trichlorobenzoic acid 

C1(=CC(=C(C(=C1Cl)C(=O)N

([H])[H])Cl)Cl)C(=O)O[H] 

COOH

CONH2Cl

Cl

Cl

Metabolism 

835.4100

Supplemental3

R417888 

CNIL/10 

2-amido-3,5,6-trichloro-4-

cyanobenzenesulfonic acid 

C1(=C(C(=C(C(=C1Cl)C(=O)

N([H])[H])[S](=O)(=O)O[H])C

l)Cl)C#N 

CONH2

N

Cl

ClCl

SO3H

Aerobic Soil 

Metabolism 

835.4100 

47207703 

Supplemental 

R471811 

CNIL/13 

Sodium 2,4-bis-amido-3,5,6-

trichlorobenzenesulfonate 

C1(=C(C(=C(C(=C1Cl)C(=O)

N([H])[H])[S](=O)(=O)[O-

])Cl)C(N([H])[H])=O)C#N.[Na

+] 

CONH2

N

Cl

Cl

H2NOC

SO3Na

Aerobic Soil 

Metabolism 

835.4100 

47207702 

Supplemental 

R419492 

CNIL/12 

4-amindo-2,5-dichloro-6-

cyanobenzene-1,3-disulphonic 

acid 

N

Cl

Cl

HO3S

SO3H

CONH2

Aerobic Soil 

Metabolism 

835.4100 

47207703 

Supplemental 
36 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

SDS-67042 

R613841 

5-cyano-4,6,7-trichloro-2H-1,2-

benzisothiazol-3-one 

4,6,7-trichloro-5-cyano-2Hbenzisothiazol-3-one 

C1(=C(C(=C2C(=C1Cl)C(NS2

)=O)Cl)Cl)C#N 

N

Cl

ClCl

S NH

O

Aerobic Aquatic 

Metabolism 

835.4300 

42226101 

Supplemental 

2,5,6-trichloro-1,3-

dicyanobenzene-4-sulphonate 

N

Cl

ClCl

SO3H N

Aerobic Soil 

Metabolism 

835.4100 

45908001 

Supplemental 

 Trichloro-1,3-dicyanobenzene 

N

Cl N 3

Aquatic Photolysis 

835.2240 

45121803 

Supplemental2 

Aerobic Aquatic 

Metabolism 

835.4300 

45908001 

Supplemental 
37 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

SDS-66382 2,5,6-trichloro-4-(glutathion-S- yl)isophthalonitrile 

N

Cl

ClCl

S N

HN

HN O

O

HO O

HO

H2N

O

Aerobic Aquatic 

Metabolism 

835.4300 

42226101 

Supplemental 

 Carbon Dioxide CO2

Aerobic Soil 

Metabolism 

835.4100 

47207703 

Supplemental 

Minor (<10%) Transformation Products 

SDS-13353 2,5,6-trichloro-4- (thio)isophthalonitrile 

N

Cl

ClCl

SH N

Aerobic Aquatic 

Metabolism 

835.4300 

42226101 

Supplemental 
38 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

SDS-66432 

N Cl

Cl

S S

N

HN

NHO

O

O

OH

OH H2N

O

NH

NH

O

O O

HO

HO NH2

O

2,5-dichloro-4,6-di-(glutathion-S-yl)isophthalonitrile 

Aerobic Aquatic 

Metabolism 

835.4300 

42226101 

Supplemental 

DS-19221 

SDS-19221 

R613636 

CNIL/03 

3-Cyano-2,4,5,6-

tertachlorobenzamide 

CONH2

N

Cl

Cl

ClCl Aerobic Soil Metabolism 

835.4100 

00040547 00087351 

Supplemental 

SDS-47524 

R611967 

CNIL/06 

3-cyano-2,5,6-

trichlorobenzamide 

CONH2

N

Cl

Cl

Cl

Aerobic Soil 

Metabolism 

835.4100

43879601 

Supplemental3 
39 

Code Name/ 

Synonym 

Chemical Name 

Smiles Code Chemical Structure 

Study Type/ 

Corresponding 

OCSPP Guideline 

MRID 

(classification) 

SDS-47525 

R611968 

CNIL/07 

3-cyano6-hydroxy-2,4,5-

trichlorobenzamide 

CONH2

N

Cl

ClCl

OH

Aerobic Soil 

Metabolism 

835.4100

47207702 

Supplemental 

R418503 

CNIL/11 

2,5 Dichloro-4,6-

dicyanobenzene-1,3-disulfonic 

acid 

N

Cl

Cl

H3OS

SO3H N

Aerobic Soil 

Metabolism 

835.4100 

4720772 

Supplemental 

R419492 

CNIL/12 

4-carbamoyl-2,5-dichloro-6-

cyano-benzene-1,3-disulfonic 

acid 

CONH2

N

Cl

Cl

H3OS

SO3H

Aerobic Soil 

Metabolism 

835.4100 

4720772 

Supplemental 

1. Bold font indicates maximum concentration was observed at study termination; therefore, the formation and decline of the tr

was not established in the experiment. 

2. Aquatic photolysis study was reclassified to supplemental as all major transformation products were not adequately identified

needed to identify all major transformation products or other residues of toxicological concern.

3. This aerobic soil metabolism study was reclassified to supplemental as all major transformation products were not adequately 

data are needed to identify all major transformation products or other residues of toxicological concern. 

Applied Radioactivity (AR) 
40 

Abiotic Degradation 

Hydrolysis

One submitted study explored the hydrolysis of chlorothalonil at pH 5, 7 and 9 [MRID 00040539 

(1976)]. The study was originally classified as acceptable; however, after recent review this 

study has been reclassified to supplemental. The portion of the study that was conducted at pH 9 

does not meet guideline standards because a material balance and characterization of the 

transformation products were not provided. The data suggest that chlorothalonil may hydrolyze 

(DT50 = 51 days) under basic conditions (pH >7), but that chlorothalonil is not susceptible to 

hydrolysis at pHs 5 and 7. Additional data are needed on chlorothalonil hydrolysis at pH 9 and 

until such data is received hydrolysis is considered a data gap. 

Aquatic Photolysis

Five aquatic photolysis studies were submitted for chlorothalonil; however, two of these studies 

[MRIDs 40183418 (1987) and 00087281 (1972)] were deemed unacceptable. These studies were 

classified unacceptable, because the intensity and spectral distribution of the artificial light 

source to natural sunlight was not provided, and identification of the transformation products was 

not provided. Another study [MRID 41030001 (1989)] is not actually an aquatic photolysis 

study. The submitted material provided supplemental information on concerns raised by EPA in 

the review of the unacceptable study, MRID 40183418, including characterization of the 

artificial light source and sample frequency. The submittal of this information does not support 

upgrading the classification of MRID 40183418. A previously classified supplemental study 

[MRID 00040540 (1976)] was reevaluated and reclassified as unacceptable because the study 

report did not adequately compare the intensity and spectral distribution of the artificial light 

source to natural sunlight, or, identify transformation products. Based on laboratory data 

generated using an artificial light source, a more recent study [MRID 45710223 (1996)] showed 

that chlorothalonil did transform under aqueous photolysis with an environmental predicted 

photo-transformation half-life of 10.3 hours (DT50 = 10.5 hours artificial light; MRID 45710223) 

at 30 °N latitude. This study was originally classified as acceptable; however, after a recent 

review this study was reclassified as supplemental. This study was reclassified because three 

major transformation products [47% of the applied radioactivity (AR)] were not identified—this 

is a data gap. Additional data are needed to identify these major transformation products or any 

other potentially toxic transformation products observed in the study. If additional data are not 

provided, the unknown residues will be assumed to be of equal toxicity to chlorothalonil or SDS3701, whichever is more conservative, for risk assessment purposes. 

Soil Photolysis

Eight soil photolysis studies have been submitted for chlorothalonil. Three of these studies were 

deemed suitable for use in risk assessment and were classified supplemental [MRIDs 00087349 

(1975), 00040543 (1976) and 00156470 (1985)] while the others have been classified as 

unacceptable (see APPENDIX A) for a number of reasons including: the studies were not 

conducted on soil or the intensity and spectral distribution of the artificial light source to natural 

sunlight was not provided. Despite the guideline deviations in the supplemental studies, it was 
41 

determined that little would be gained from repeating these studies as no substantial degradation 

of chlorothalonil was observed in these studies; therefore, chlorothalonil is considered stable to 

soil photolysis. 

Biotic Degradation 

Aerobic Soil Metabolism

Six aerobic soil metabolism studies have been submitted for chlorothalonil. Two of the six 

studies [MRIDs 00087285 (1970) and 00114035 (1970)] were determined to be unacceptable 

because the studies were conducted with bacterial cultures (inoculated with soil perfusions) and 

not soil. These studies were not reevaluated as part of this problem formulation. The remaining 

studies have been classified as supplemental, and are discussed individually, below. 

One of the aerobic soil metabolism studies appears to have been submitted twice and as a result 

was given two different MRID numbers (MRIDs 00087351/00040547(1976)). For this study, 

two different application rates were used - 8 and 78 lb a.i./a. The highest application rate is much 

higher (6 times) than the current application rate (13 lb a.i./a) permitted on registered 

conventional pesticide chlorothalonil use labels. Chlorothalonil transformation half-lives ranged 

from 10 to 58 days using non-linear single first order (SFO) kinetic model; however, 

chlorothalonil does not follow SFO degradation kinetics. Upon additional kinetic analysis using 

Nth-Order Rate Model or Indeterminate Order Rate Equation Model (IORE), and Double FirstOrder in Parallel (DFOP) models,12 representative half-life values for chlorothalonil were 

determined to range from 16-127 days. Chlorothalonil concentrations decrease at the beginning 

of the study; however, after approximately 20-40 days chlorothalonil concentrations become 

steady at approximately 40-50% of the AR in one soil and 10-20% of the AR in the other three 

soils tested. In general, the transformation of chlorothalonil depends on the application rate as 

the highest application rate resulted in the longest half-life while the lowest application rate 

resulted in the shortest half-life. A substantial amount of chlorothalonil transformation was 

observed in the sterile control (half-life values ranged from 33-105 days). It is unclear if this 

transformation is representative of another dissipation pathway or if the soils were not sterile. In 

three of the four sterile control experiments, chlorothalonil transformation can be described using 

SFO. Chlorothalonil transformation in the fourth control experiment is best described using 

IORE. Two transformation products were identified in this study, SDS-3701 (34.1% AR) and 

DS-19221 (7.3% AR). Although these transformation products were identified, a material 

balance could not be determined because unextracted residues were not measured and it is 

unclear if all major, or potentially toxic, transformation products were identified. Up to 27% of 

the applied radioactivity was found in the aqueous extracts. This material was not characterized. 

In another aerobic soil metabolism study, chlorothalonil was also investigated at application rates 

of approximately 2 and 20 lb a.i./a [MRID 43879601 (1995)]. The corresponding half-lives were 

6 and 21 days using a non-linear SFO kinetic model, respectively. Nevertheless, chlorothalonil 

transformation was shown not to follow SFO kinetics. Upon additional kinetic analysis, the 

representative half-life values for chlorothalonil were determined to be 18 and 35 days using 

 

12 Guidance for Evaluating and Calculating Degradation Kinetics in Environmental Media (draft document June 29, 

2011). 
42 

IORE, respectively. These results also suggest that chlorothalonil transformation depends on the 

application rate. Neither of the two application rates used in this study are representative of the 

current maximum single rate (13 lb a.i./a). Transformation products identified in this study 

include SDS-3701 (14% AR), SDS-19221 (6.35% AR), SDS-47523 (10% AR), SDS-47524 

(13.77 % AR), SDS-47525 (4.73% AR), and SDS-46851 (19% AR). One major transformation 

product (representing up to 12% AR) was not identified in this study. 

The aerobic soil metabolism of chlorothalonil was also investigated over a range of application 

rates [approximately 0.2-50 lb a.i./a; MRID 47207702 (2000)]. This study also showed that the 

transformation rate of chlorothalonil depends on the soil application rate. Estimated 

chlorothalonil half-lives ranged from less than a day to 18 days using SFO kinetics. The 

transformation of chlorothalonil is best described using IORE for three of the test concentrations 

and SFO for one of the test concentrations. The representative half-life values ranged from less 

than one day for the lowest application rate (0.2 lb a.i./a) to 243 days for the highest application 

rate (50 lb a.i./a). This study also shows that any chlorothalonil present after approximately 20-

40 days is no longer metabolized. The range of application rates tested in this study spans the 

current maximum application rate; however, the current maximum application rate was not 

tested. No data on transformation of chlorothalonil were provided until day two; therefore, the 

half-life values above were derived assuming a 100% of the applied radioactivity was present on 

day one. This introduces uncertainty in the representation of the calculated half-life values, 

especially for the lowest application rate tested as the estimated half-life value was less than two 

days. This uncertainty limits the usefulness of the data for risk assessment purposes. This study 

also did not include soil characterization, duplicate samples, or sterile controls, further 

complicating the interpretation of the study. Transformation products identified in this study 

include SDS-3701, R417888, R471811, SDS-19221, SDS-47523, SDS-47524, SDS-47525, 

R419492, SDS-46851 and CO2. 

The last aerobic soil metabolism study submitted for chlorothalonil indicates half-life values 

ranged from 1 to 2.5 days using (SFO); however, SFO does not best describe the data [MRID 

47207703 (2001)]. In all four soils the transformation of chlorothalonil is best described by 

IORE with representative half-life values ranging from less than one day to up to four days. 

These results are for chlorothalonil applications around 1 lb a.i./a, and are consistent with other 

studies conducted with a similar application rate. This study was originally classified as an 

acceptable study; however, this study has been reclassified to supplemental as the results may 

not represent the half-life value of the current maximum single chlorothalonil application rate 

(13 lb a.i./a) or a large number of other current maximum single chlorothalonil application rates 

(see Table 4). For chlorothalonil the application rate has been shown in other studies to influence 

the rate of transformation. These reported half-life values should not be used to represent the 

current chlorothalonil use pattern. Transformation products identified in this study include 

R182281, R417888, R419492, SDS-19221, SDS-46851, SDS-47523, R471811 and CO2.

 

Taken together, these aerobic soil metabolism studies demonstrate that chlorothalonil can 

undergo a number of different chemical reactions in the soil to form a number of transformation 

products. All the transformation products reported retain the phenyl ring with the exception of 

CO2. Maximum observed concentrations of each of these transformation products reported in the 

submitted aerobic soil metabolism studies are highlighted in Table 7. The transformation rate of 
43 

chlorothalonil was also shown to be heavily influenced by the application rate. Higher 

application rates result in longer half-life values while lower application rates result in shorter 

half-life values (MRIDs 43879601, 47207702, 00087351 and 00040547). This is likely the result 

of a decrease in viability of the soil microbes after exposure to chlorothalonil. This is supported 

by a decrease in observed microbial activity at study termination as compared to study initiation 

(MRID 47207703). All aerobic soil metabolism kinetic analyses are provided in APPENDIX B. 

In general, this suite of studies indicate that chlorothalonil degrades over the first 20 days; 

however, if any chlorothalonil remains after 20-40 days it is not likely to be metabolized or it is 

metabolized very slowly. This was generally observed for all application rates. Representative 

half-life values for chlorothalonil compared to application rates used in the submitted studies that 

span the current single maximum application rates are provided in Table 8. Based on the data 

presented in this table, the half-life value for the currently approved maximum application rate is 

likely between 18-35 days; however, additional data are needed to confirm this assumption. 

Table 8. Representative Aerobic Soil Metabolism Half-life Values for Chlorothalonil in 

Relationship to Experimental Application Rates and Current Maximum Single Application 

Rate 

Application Rate 

(lb a.i./a)

Representative 

Half-life (days) Source Comments 

1 2 

MRID 47207703 

IORE best fit kinetic 

model 

1 1 

1 2 

1 4 

2 18 MRID 43879601 

2 18* MRID 47207702 

8 16 MRIDs 

00087351/00040547 

20 35 MRID 43879601 

20 10* MRID 47207702 SFO best fit kinetic 

model 

50 243* MRID 47207702 IORE best fit kinetic 

model 

*The half-life value is estimated as data were not provided until two days after treatment. 

Zigzag line represents current maximum single application rate. 

Anaerobic Soil Metabolism

No anaerobic soil metabolism data has been submitted. This is considered a data gap. In absence 

of this data the anaerobic aquatic metabolism rate may be used as a surrogate. A supplemental 

anaerobic aquatic metabolism (MRID 00147975) study has been submitted (see discussion 

below). 

Aerobic Aquatic Metabolism

Three different aerobic aquatic metabolism studies have been submitted for chlorothalonil. All of 

these studies have been classified as supplemental. All three studies indicate that chlorothalonil 

transformation is rapid (<1 day). Nevertheless, all of these studies have deficiencies that limit the 

use of the data for risk assessment purposes. One common deficiency is that none of the studies 
44 

identified all the major transformation products. One of the studies [MRID 45908001 (1996)] 

report fluctuating chlorothalonil concentrations (going up and down) and thus corresponding 

half-life values should not be used quantitatively in a risk assessment. In another study (MRID 

42226101(1991)], artificial sources of water were used and the resulting half-life values may not 

accurately represent those found in natural water bodies. Additional data are needed on the 

transformation rate of chlorothalonil in aerobic aquatic systems, as well as full characterization 

of all major transformation products or transformation products of toxicological concern. Until 

such information is received aerobic aquatic metabolism is considered a data gap. 

Anaerobic Aquatic Metabolism

One supplemental anaerobic aquatic metabolism study [MRID 00147975 (1985)] has been 

submitted. These data suggest that chlorothalonil can transform under anaerobic conditions; 

however, after reevaluation of the study several deficiencies have been noted that limit the use of 

these data for risk assessment purposes. Redox potentials and oxygen concentrations were not 

provided during the experiment; therefore, it cannot be confirmed that the system was anaerobic. 

Since the test system was purged with nitrogen for 30 days prior to study initiation it is assumed 

that the study was conducted under anaerobic conditions; however, additional data are needed to 

confirm this assumption. In addition, no data are provided for day 0. For this reason, 

chlorothalonil concentration at day 0 was assumed to be 100% of the applied radioactivity. The 

study was also terminated before the pattern of formation and decline could be established for 

the transformation products in one of the test systems. The test systems used in this experiment 

are soil and distilled water. Current guidelines indicate that anaerobic aquatic metabolism studies 

should be conducted with sediment (not soil) along with natural water (not distilled water). For 

all the reasons mentioned above, the anaerobic aquatic metabolism study is considered a data gap 

without additional information. 

Adsorption/Desorption-Batch Equilibrium 

One supplemental adsorption study [MRID 00029406 (1980)] indicates that chlorothalonil is 

slightly to hardly mobile in soils (KF range from 12 to 500 L/kg-soil while Koc values range from 

1121 to 11935 mL/gOC). The leaching potential of chlorothalonil through soil is correlated with 

the organic carbon fraction of the soil. The Freundlich exponent (1/n) ranges from 0.7 to 1.2, 

suggesting that adsorption is non-linear. This study did not investigate the desorption of 

chlorothalonil from soil, and this is considered a data gap. 

Terrestrial Field Dissipation

Two supplemental terrestrial field dissipation studies [MRIDs 00071625 (1981) and MRIDs 

00071627, 00087332, 00087369, 00087301 (1980, 1967 and 1965)] are available for 

chlorothalonil. In both of these studies, sampling did not begin until at least one month after 

chlorothalonil applications. This limits the ability to estimate a representative half-life value for 

chlorothalonil, as well as for any chlorothalonil transformation products. In addition, both of 

these studies also have additional deficiencies as listed in Table 6, including limited 

characterization of environmental transformation products. The estimated half-life values suggest 

that substantial amounts of applied chlorothalonil could be available for runoff or soil-sorbed 
45 

erosion transport for several weeks to months post-application (estimated half-life values ranged 

from 33 to 81 days). Terrestrial field dissipation is considered a data gap for chlorothalonil. 

Fish Bioaccumulation

A fish bioconcentration [MRID 45710224 (1997)] study showed that chlorothalonil is absorbed 

by fish; however, it depurates when exposure ceases (approximately 31-35% decrease after one 

day). For the two different concentrations tested (0.1 μg/L and 0.5 μg/L) the bioconcentration 

factor (BCF) were determined to range from 256-306, 5694-5812 and 3041-3077 for the edible, 

non-edible, and whole fish tissues, respectively. Three transformation products were identified to 

form—triglutathione and diglutathione conjugates and SDS-3701. Several other transformation 

products were observed. These transformation products did not make up more than 10% AR 

combined. Up to 28 % of the AR was identified as polar components and not characterized while 

up to 15% of the radioactivity was not extracted. 

An oyster bioconcentration (MRID 43070601) study showed that chlorothalonil is adsorbed by 

oysters. A total residue BCF (primary transformation products) was determined to be 2600 

suggesting there is some potential for bioaccumulation of chlorothalonil transformation products. 

Dissipation 

Spray Drift

Based on conventional use patterns there is the potential for chlorothalonil to drift following 

application. Spray drift results in deposition to adjacent areas including terrestrial habitats and 

aquatic environments that serve as habitat or source water for drinking water. In general, 

deposition of drifting or volatilized pesticides is expected to be greatest closest to the site of 

application. 

As result of the 1999 RED, all agricultural labels were updated to include a buffer zone between 

agricultural fields (including sod farms, farms, forests, nurseries and greenhouses) and 

marine/estuarine water bodies. The required buffer is 150 feet for aerial and air-blast applications 

and 25 feet for ground applications. 

 
46 

Overspray-Antimicrobial Coating Applications

Application of exterior paints, stains, and coatings using air or airless spray equipment13 has the 

potential, due to overspray, to result in deposition to adjacent areas. This is considered a 

negligible exposure pathway of antimicrobials for nontarget organisms due to a combination of 

factors. With delivery rates of paint on the order of 0.24 gallons per minute (gpm) to greater 

than 1 gpm (0.91 to >3.8 liters per minute) for airless sprayers14, median droplet size is expected 

to be in the hundreds to thousands of micron size range which is much larger than particle sizes 

that are more prone to drift (<150 microns). Additionally, the high percent solids content in 

paints, stains and coatings (20-70% solids for exterior coatings15) is expected to drastically 

reduce the distance overspray would travel from the point of application as compared to spray 

drift from agricultural spray applications. While such conditions are expected, to the best of the 

Agency’s knowledge there is no quantitative information available on the distance paints, stains, 

and coatings drift from various spray equipment applications. In OECD Emission Scenario 

Document Number 22 for Coatings15 the estimate of drift is 1 to 10% based on a review of 

general and agricultural spray drift information in support of Emission Scenario Document for 

Biocides used as Masonry Preservatives,16 At the highest chlorothalonil active ingredient content 

in paint (0.12 lbs per gallon), if 10% drifted over a perimeter of 25 ft the loading rate is <1 lb 

a.i./acre. Another factor considered is that the frequency of overspray occurring at any given 

location will be extremely limited as the life expectancy of paint on exterior home building 

wood, aluminum, or brick components is 7 to 10 years17,18. Smaller structural elements such as 

decks which have been treated with clear, preservative coatings may require more frequent 

treatment (life expectancy 1 to 2 years) but due to the small size of these structure, the Agency 

expects that environmental loading will be negligible despite the more frequent applications. 

Volatilization 

Based on laboratory data, the vapor pressure (5.7 x 10-7 torr) and Henry’s Law Constant (2.6 x 

10-7 atm - m3/mole) values for chlorothalonil indicate some degree of volatility from both soil 

and water (semi-volatile). However, volatilization would not be expected to be a major 

dissipation route. Nonetheless, a number of studies have documented atmospheric transport and 

redeposition of various pesticides, including chlorothalonil, from the Central Valley to the Sierra 

Nevada Mountains.19,20,21 This is likely the result of prevailing winds blowing across the Central 

 

13 0-1 bar or 0-14.5 pounds per square inch of pressure 

14 http://www.portlandcompressor.com/airless/tip-sizing.aspx 15 Emission Scenario Documents on Coatings Industry (Paints, Laquers, Varnishes). OECD Series on Emission 

Scenario Documents Number 22. ENV/JM/MONO(2009)24. 

http://www.oecd.org/officialdocuments/displaydocumentpdf/?cote=env/jm/mono(2009)24&doclanguage=en 16 Migne, V. 2002. Supplement to the methodology for risk evaluation of biocides. Emission scenario document 

for biocides used as masonry preservatives (product type 10). Institut National De L’Environnement Industriel Et 

Des Risques (INERIS). CA-Jun03-Doc.8.2-PT10. 

17 http://www.fpl.fs.fed.us/documnts/finlines/knaeb95b.pdf 18 Appendix C –Life Expectancy of Housing Components. National Association of Home Buliders Economics 

Department. http://www.metrohome.us/information_kit_files/life.pdf 19 Fellers, G.M, L.L. McConnell, D. Pratt, S. Datta. 2004. Pesticides in Mountain Yellow-Legged Frogs (Rana 

Mucosa) from the Sierra Nevada Mountains of California, USA. Environ. Tox. Chem. 23 (9):2170-2177. 

20 Sparling, D.W., Fellers, G.M., McConnell, L.L., 2001. Pesticides and amphibian population declines in California 

USA. Environ. Tox. Chem. 20: 1591-1595. 
47 

Valley eastward to the Sierra Nevada Mountains transporting airborne pollutants such as 

chlorothalonil into the Sierra Nevada ecosystems. In addition, local ambient air monitoring data 

from a site in North Dakota and three sites in California, to list a few, indicate that chlorothalonil 

was present in the air at application sites and at locations up to a mile away from the application 

sites.22 Data from the state of Montana show detections of chlorothalonil in precipitation. This 

indicates that chlorothalonil volatility or particle phase transport plays a role in the dissipation of 

chlorothalonil and that it is possible for chlorothalonil exposure to occur adjacent to application 

sites, as well as areas distant from application sites (long range transport). 

The magnitude of transport via secondary drift depends on the amount of chlorothalonil that 

becomes mobilized into air and its eventual removal through wet and dry deposition of gases, 

and particles and photochemical reactions in the atmosphere. Currently, the Agency does not 

have data on direct and indirect chlorothalonil phototransformation (OCSPP 835.2370). 

Therefore, physicochemical properties of chlorothalonil that describe its potential to enter the air 

from water or soil (e.g., Henry’s Law constant and vapor pressure), pesticide use data, modeled 

estimated concentrations in water and air, and available air monitoring data will be considered in 

evaluating the potential for atmospheric transport of chlorothalonil. In order to reasonably 

estimate concentrations of chlorothalonil in air, additional information is needed, including flux 

data, for chlorothalonil from a field volatility study (OCSPP 835.8100). 

Volatilization from freshly applied wood preservative or exterior paints, stains, and coatings, 

stucco, grout, adhesives, sealants or volatilization from these materials after they have cured or 

dried is not expected to be a major or significant dissipation route or exposure pathway for nontarget organisms. Unlike agricultural uses, application of these products by homeowners or 

professionals is limited in both time and spatial extent. For example, homes made out of cedar 

or other wood types, depending on the harshness of the climates, are repainted every three to 

seven years, while newer siding materials require paint every 10 to 15 years.23 Spray 

applications are limited in spatial extent to areas smaller than a single house (e.g., furniture, 

concrete driveway or sidewalk), up to the size of a house or building structure. At such a 

localized scale and limited time scale for vulnerability to rapid volatilization, and expected 

relatively instant dilution and turbulence in air, exposure of nontarget organisms would be 

negligible for these uses. 

Runoff

Fate data indicate that chlorothalonil can dissipate in the environment after application via 

dissolved phase and sorption to eroded sediment. To gain a better idea of the potential exposure 

to chlorothalonil as a result of these dissipation pathways, PRZM (Pesticide Root Zone Model) 

will be used to simulate pesticide transport as a result of runoff and erosion from an agricultural 

field. In addition to model estimates, monitoring data will also be evaluated. 

 21 LeNoir, J.S., L.L. McConnell, G.M. Fellers, T.M. Cahill, J.N. Seiber. 1999. Summertime Transport of Currentuse pesticides from California’s Central Valley to the Sierra Nevada Mountain Range, USA. Environmental 

Toxicology & Chemistry 18(12): 2715-2722. 

22 JOURNAL OF PESTICIDE REFORM/ WINTER 1997 • VOL.17, NO. 

http://64.233.161.104/search?q=cache:0yXOLRyW_IUJ:www.pesticide.org/chlorothalonil.pdf+chlorothalonil+moni

toring&hl=en&gl=us&ct=clnk&cd=5 

23 http://www.ehow.com/way_5231946_should-paint-house_.html 
48 

Monitoring data can elucidate what is happening under current use practices and under typical 

conditions. Although monitoring data can provide a direct estimate of the concentration of a 

pesticide in water, it does not always provide a reliable estimate of peak exposures because 

sampling may not occur where the highest pesticide concentrations are found and/or sampling 

may not occur when the pesticide concentrations are the highest. In addition, monitoring is often 

conducted for purposes other than characterizing exposure from a particular pesticide. A useful 

interpretation of monitoring values requires in-depth assessment of the data. A thorough 

examination of available monitoring data will be conducted as part of the registration review 

exposure assessment. A brief summary of what is currently known about available monitoring 

data is provided below by media. 

 The NAWQA (USGS National Water Quality Assessment Data Warehouse) is a national-scale 

assessment program that contains monitoring data for pesticides in streams. The NAWQA 

monitoring program was not designed to specifically target chlorothalonil use; however, the 

database includes data for chlorothalonil (NAWQA parameter codes 49306 and 70314). 

NAWQA reports chlorothalonil detections in surface water. These data will be evaluated and 

specific attention will be paid to the sample timing and frequency of sampling. 

California Department of Pesticide Regulation (CalDPR) also has data on detections of 

chlorothalonil in surface water samples. 

The Agency invites submission of water quality data for chlorothalonil. 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. 

Soil Leaching

NAWQA reports detections of chlorothalonil transformation products in groundwater. In 

addition, groundwater monitoring data from Suffolk County, New York (MRID 44006001, 

1996) confirmed that chlorothalonil metabolites were present in ground water. These data will be 

evaluated and specific attention will be paid to the sample timing and frequency of sampling. 

Several interim reports [MRIDs 43959401 (1996), 43959402 (1996), and 44254801 (1997)] 

submitted to the Agency by the registrant for a small-scale prospective groundwater study 

suggest that chlorothalonil and some of its environmental transformation products can leach to 

groundwater. The final report for this study has not been submitted to the Agency. To date the 

interim reports have not been fully reviewed. The Agency will consider all available data during 

the risk assessment phase of registration review. 
49 

Treated Wood Leaching

No leaching studies of chlorothalonil and its major transformation products are available for 

treated wood. These data are needed to conduct the ecological assessment for wood preservative 

uses.” 

Clean Water Act 

Organochlorine pesticides are identified as a cause of impairment for two water bodies listed as 

impaired under section 303(d) of the Clean Water Act as of the water body report completed in 

2010. 24 It is unclear if chlorothalonil is one of the organochlorine pesticides contributing to the 

water body impairment. The two water bodies are Niagara River, upper, main stem and Niagara 

River, lower, main stem. A Total Maximum Daily Loads (TMDL)25 has not been developed for 

chlorothalonil or organochlorine pesticides. 

SDS-3701 

As mentioned above, chlorothalonil is likely to transform to form SDS-3701 under various 

environmental conditions. SDS-3701 is much more soluble (115.7 mg/L at 25 °C; EPI Web 4.0 

WSKOW v. 1.41) than chlorothalonil. Laboratory studies suggest that SDS-3701 may also 

transform through microbial-mediated processes, and is more mobile than chlorothalonil (see 

Tables 6, 7, and 9). A summary of the environmental fate properties of SDS-3701 is provided in 

Table 9. A detailed discussion of each of the relevant environmental fate studies is provided in 

the subsections below. 

Table 9. Environmental Fate Parameters of SDS-3701 

Parameter Value Source 

Classification; Comments

Abiotic Transformation Mechanisms

Hydrolysis Half-life No data 

Soil Photolysis Half-life No data 

Biotic Transformation Mechanisms 

Aqueous Photolysis 

half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty.1

 

Aerobic Soil 

Metabolism Half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty.

Anaerobic Soil 

Metabolism Half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty.

Aerobic Aquatic 

Metabolism Half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty.

Anaerobic Aquatic 

Metabolism Half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty.

 

24 http://iaspub.epa.gov/tmdl_waters10/attains_nation.cause_detail_303d?p_cause_group_id=885&p_cycle=2010 

25 http://www.epa.gov/owow/tmdl/ 
50 

Parameter Value Source 

Classification; Comments

Mobility

Range of Freundlich 

soil-water partition 

coefficients (KF); 

exponent (1/n) value; 

and 

organic carbonnormalized coefficients 

(KFOC) 

5, 9, and 11 L/kg-soil 

0.96, 0.87, and 0.91; and 

718, 351 and 559 mL/gOC

MRID 46786901 

Supplemental 

Field Dissipation 

Terrestrial field 

dissipation half-life No data 

Concentrations of SDS-3701 can be added to 

chlorothalonil in a total toxic residue approach 

to account for this uncertainty. 1

This approach can only be used for SDS-3071 as it is identified in the chlorothalonil studies. 

EPA does not currently anticipate requiring any environmental fate-related data for any of the 

other chlorothalonil environmental transformation products or manufacturing byproducts like 

HCB and dioxin/furans. In the absence of these data, if degradates of similar toxicity to 

chlorothalonil are identified as residues of toxicological concern a total toxic residue method will 

be employed to derive estimated environmental concentrations. 

Environmental Transport Assessment for Conventional Pesticide Use 

Possible routes of transport of pesticides, and pesticide transformation products including 

chlorothalonil and its environmental transformation products, are illustrated in Figure 4. In 

addition to fate data, monitoring data suggest that chlorothalonil can dissipate in the environment 

after application via dissolved phase (dissolved in water); eroded sediment, spray drift, and 

volatilization are probable environmental transport mechanisms for chlorothalonil. 

Chlorothalonil applications can lead to surface water contamination as a result of spray drift as 

well as through runoff and sediment erosion. Aerobic soil metabolism data indicated that once 

chlorothalonil reaches the soil it can be transformed to SDS-3701 (a transformation product of 

toxicological concern) as well as several other transformation products (discussed further in the 

environmental fate section of this document). The soil/water partitioning of chlorothalonil 

indicates that chlorothalonil runoff is generally by dissolution in runoff water rather than soil 

erosion (i.e., chlorothalonil is not expected to readily sorb to soil and sediment). Chlorothalonil 

may also leach through the soil. SDS-3701 may also reach surface water though runoff and 

sediment erosion. SDS-3701 as well as other chlorothalonil soil transformation products has 

been shown to leach to groundwater. Once in surface water, chlorothalonil is expected to 

transform rapidly via aqueous photolysis as well as metabolism. 
51 

Figure 4. Potential Routes of Pesticide Dissipation in the Environment 

Environmental Transport Assessment for Antimicrobial Pesticide Uses 

For chlorothalonil applied to wood (e.g., lumber, timber) at the industrial scale by dip (bulk and 

non-bulk vats), pad, spray, or pressure treatment, there is potential for emissions of 

chlorothalonil and its major transformation products to waste water treatment plants (WWTPs) 

with subsequent discharge to surface water, and to soil and surface water from leaching of 

treated wood during storage and in-service use of the wood (OECD, 2000) (see Figure 7). 

Manufacturing of paints, stains, and coatings with film preservatives added can also result in 

discharge of chlorothalonil to WWTPs. For chlorothalonil spray, pad, or brush applied as a wood 

preservative or as an antimildew/antimold surface protectant, leaching from exterior surfaces of 

treated items (e.g, fencing, shakes, decking, treated concrete, stucco, etc.) to soil with subsequent 

run-off to surface water and/or leaching from soil to groundwater has the potential to occur. 

Aerobic soil metabolism data indicated that once chlorothalonil reaches the soil it can be 

transformed to SDS-3701 (a residue of potential toxicological concern) as well as several other 

transformation products (discussed further in the environmental fate section of this document). 

The soil/water partitioning of chlorothalonil indicates that chlorothalonil runoff is generally by 

dissolution in runoff water rather than soil erosion. Chlorothalonil may also leach through the 

soil. SDS-3701 may also reach surface water though runoff and sediment erosion. SDS-3701 as 

well as other chlorothalonil soil transformation products has been shown to leach to 

groundwater. Once in surface water, chlorothalonil is expected to transform rapidly via aqueous 

photolysis as well as aqueous metabolism. 

E. ECOLOGICAL EFFECTS

The Agency evaluates the potential for adverse effects as a result of chlorothalonil usage. As 

described in the Agency’s Overview Document (U.S. USEPA, 2004), 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 

and estuarine/marine fish, freshwater and estuarine/marine invertebrates, aquatic plants, birds, 

mammals, terrestrial invertebrates, and terrestrial plants. The environmental fate and toxicity of 
52 

chlorothalonil have been discussed in depth in the 1997 Science Chapter for the Reregistration 

Eligibility Decision document published in 1999, and readdressed in previous risk assessments 

(D301163, D301165, 2004 and D371947, 2009). A brief summary of toxicity data is provided in 

Tables 10 through 12. Toxicity endpoints are based on data generated from guideline studies 

submitted by the registrant, and from open literature studies that meet the criteria for inclusion 

into the ECOTOX database maintained by the Office of Research and Development (U.S. EPA, 

2004).26 

Acute (short-term) and chronic (long-term) toxicity information is characterized based on 

registrant-submitted studies and a comprehensive review of the open literature on chlorothalonil. 

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

establish the probability of an individual effect and reviews of ecological incident reports, are 

conducted to further refine the characterization of potential ecological effects associated with 

exposure to chlorothalonil. A summary of the available ecotoxicity information and the incident 

information for chlorothalonil are provided below. 

The available data for chlorothalonil (Tables 10 and 11) indicate that the technical grade active 

ingredient (TGAI) is: 

• Very highly toxic to freshwater and saltwater organisms (96-h LC50 = 18 μg a.i./L, 

rainbow trout; 48-h EC50 = 54 μg a.i./L, freshwater crustacean); 

• Practically nontoxic to small mammals on an acute oral basis, based on rat data (LD50

>10,000 mg/kg-bw; 

• Practically nontoxic to birds on an acute oral basis (LD50 >4,640 mg/kg-bw for mallard 

ducks and >2,000 mg/kg-bw for Japanese quail) and a sub-acute dietary basis (LD50

≥21,500 mg a.i./kg-diet for mallard and >10,000 mg a.i./kg-diet for bobwhite quail); 

• Practically nontoxic to honey bees (LD50 > 181 μg/bee); 

Also: 

• The EC50 for non-vascular aquatic plants (freshwater diatoms) is 12 μg a.i./L, and the 

EC50 for aquatic vascular plants (duckweed) is 640 μg a.i./L; 

• The EC25 for inhibition of growth in terrestrial plants is approximately 16 lb a.i./A. 

For birds, no mortality occurred in studies that tested up to 4640 mg/kg-bw in an acute oral 

gavage study and at dietary concentrations up to 21,500 mg a.i./kg-diet in subacute studies. 

However, there was reduced body weight gain at various concentrations in several of the acute 

and sub-acute studies (e.g., MRIDs 00068753, 00030388, 00039146). For mammals, no 

mortality occurred up to 10,000 mg/kg-bw, the highest dose tested, but clinical signs of toxicity 

(e.g., decreased activity, diarrhea, tremors, and decreased reflexes and muscle tone) were present 

(MRID 00094941). 

Chronic toxicity studies established the following no-observable adverse effect concentration 

(NOAEC) values: birds 153 mg a.i./kg-diet, bobwhite quail; small mammals 1,200 mg a.i./kg-

 

26 http://cfpub.epa.gov/ecotox/ 
53 

diet, rat; freshwater fish 1.3 μg a.i./L, fathead minnow; freshwater invertebrates 0.6 μg a.i./L, 

daphnia; and estuarine invertebrates <0.65 μg a.i./L, mysid. 

Tables 10 and 11 summarize the most sensitive ecological toxicity endpoints for parent 

chlorothalonil based on currently available data. A brief summary of submitted data considered 

relevant to this ecological risk assessment is presented below. Additional data have also been 

submitted by the registrant regarding toxicity of a multi-a.i. formulation (chlorothalonil and 

penthiopyrad) to a variety of non-target terrestrial invertebrates. These will be reviewed and 

evaluated to determine potential use in the ecological risk assessment. 

Table 10. Aquatic Toxicity Profile for Chlorothalonil 

Taxon 

Exposure 

Duration 

Most Sensitive 

Species Tested Toxicity Value

Acute 

Toxicity 

Category 

Classification Source 

Freshwater Fish 

Acute 

Rainbow trout 

Onchorynchis 

mykiss 

96-hr LC50= 

18 μg a.i./L 

Very Highly 

toxic Acceptable MRID 45710219 

Chronic 

Fathead minnow

Pimephales 

promelas 

NOAEC = 

1.3 μg ai/L N/A Supplemental1 MRID 00030391 

Freshwater 

Invertebrates 

Acute 

Water Flea 

Daphnia 

 magna 

48-hr EC50 = 

54 μg a.i./L 

Very highly 

toxic Acceptable MRID 

45710221 

Chronic Water Flea 

Daphnia magna

21-day 

NOAEC = 0.6 

μg ai/L 

N/A Supplemental2 MRID 

45710222 

Saltwater Fish Acute No acceptable study available3

Chronic No data available 

Saltwater 

Invertebrates 

Acute 

Eastern oyster 

Crassostrea 

virginica

96- hr 

EC50 = 3.6 μg 

a.i./L 

(shell 

deposition) 

Very highly 

toxic Acceptable MRID 00138143 

Chronic No acceptable study available4

Non-vascular 

plant -- 

Diatom 

Navicula 

pelliculosa

5-d EC50 = 

12 μg a.i./L 

NOAEC = 

3.9 μg a.i./L 

(based on area 

under curve) 

N/A Acceptable MRID 

44908105 

Vascular plant -- Duckweed 

Lemna gibba

7-d EC50 = 

640 μg ai/L 

NOAEC = 

290 μg ai/L 

(based on dry 

wt) 

N/A Acceptable 

MRID 

44908102 
54 

Taxon 

Exposure 

Duration 

Most Sensitive 

Species Tested Toxicity Value

Acute 

Toxicity 

Category 

Classification Source 

1 This endpoint is appropriate for quantitative use; classified Supplemental due to replicate size and solvent control 

mortality. 

2 Classification based on instability of the test substance as measured concentrations were below detection for 

several concentrations at the end of a renewal period. The endpoint values for this study are derived on the basis of 

biological significance and not statistical significance. Given that the study was conducted as a static renewal with 

non-detection levels accounted for in the concentration estimates by using a value of zero for the non-detects [i.e. 

the compound was unstable between media renewal intervals but the shape of the decline curve for the chemical is 

unknown]. 

3

A study with sheepshead minnow was available (MRID 00127863); however, given the uncertainties in the 

exposure concentrations (nominal concentrations in a static system), the endpoint value is for qualitative use only 

and a new study is requested. 

4

 A mysid life-cycle study (MRID 42433807) was available and originally the study was classified as unacceptable. 

Prior to Registration Review, the study was reclassified to acceptable, but as part of a re-evaluation during 

Registration Review, it has been downgraded to unacceptable once again.

Table 11. Terrestrial Toxicity Profile for Chlorothalonil 

Taxon Exposure 

Duration 

Most Sensitive 

Species Tested Toxicity Value 

Acute 

Toxicity 

Category 

Classification Source 

Mammals 

Acute Oral 

Rat 

Rattus 

norvegicus 

LD50 = >10,000 

mg/kg-bw 

Practically 

non-toxic Acceptable MRID 00094941 

Chronic Repro 

Rat 

R. norvegicus 

2-Generation 

repro

NOAEL = 1,200 mg 

a.i./kg-diet 

(92.5 mg a.i/kg-bw) 

LOAEL = 3,000 mg 

a.i./kg-diet 

N/A Acceptable MRID 

45710209 

Birds 

Acute Oral 

Passerine species No Data -- -- -- 

Mallard Duck 

Anas 

platyrhynchos 

LD50 >4640 mg/kg – 

bw 

Practically 

non-toxic Acceptable MRID 

00068753 

Subacute 

dietary 

Mallard Duck 

A. platyrhynchos

LC50 >21,500 mg 

a.i./kg-diet 

Practically 

non-toxic Acceptable MRID 

00039146 

Bobwhite quail 

Colinus 

virginianus

LC50 >10,000 mg 

a.i./kg-diet 

Practically 

non-toxic Acceptable MRID 00030388 

Chronic Repro Bobwhite quail 

C. virginianus

NOAEC = 153 mg 

a.i./kg-diet 

LOAEC = 624 mg 

a.i./kg-diet 

N/A Acceptable MRID 

45710218 

Terrestrial 

Invertebrates Acute Honey Bee Apis mellifera LD50 >181 μg a.i./bee Practically 

non-toxic Acceptable MRID 00077759 

Terrestrial 

Plants 

Seed germination/seedling 

emergence--

Tier 1 

10 species 

EC25 = >16 lb a.i./A 

NOAEL < 16 lb 

a.i./acre (for onion) 

N/A Acceptable MRID 

42433808 

Vegetative 

vigor--Tier 1 10 species 

EC25 = >16 lb a.i./A 

NOAEL < 16 lb 

a.i./acre (for 

cucumber) 

N/A Acceptable MRID 

42433809 
55 

The major degradate of chlorothalonil previously identified as of toxicological concern is SDS3701. The toxicity data for this chemical, summarized in Table 12, are available for freshwater 

fish/invertebrates, aquatic plants, mammals, and birds. 

For the major degradate SDS-3701 acute toxicity data indicate that it is: 

• Moderately toxic to very highly toxic (more toxic than parent) to small mammals (oral 

LD50 = 242 mg/kg-bw, rat acute; 6 mg/kg-bw, rat chronic); 

• Slightly toxic to moderately toxic (more toxic than parent) to birds (LD50 = 158 mg/kgbw, mallard duck acute oral toxicity; 1746 ppm, bobwhite quail sub-acute dietary 

toxicity); 

• Slightly toxic to moderately toxic (less toxic than parent) to aquatic organisms (96-hr 

LC50 = 9.2 ppm, bluegill sunfish; 48-h EC50 = 26 mg/L, daphnia); and 

• Less toxic than parent to algae (EC50 = 33.7 mg/L). 

Table 12. Aquatic and Terrestrial Toxicity Profile for SDS-3701 

Taxon Exposure 

Duration 

Most Sensitive 

Species Tested Toxicity Value 

Acute 

Toxicity 

Category 

Source 

Freshwater 

Fish Acute Bluegill sunfish 

Lepomis macrochirus

96 h LC50 = 9,200 μg/L 

SDS-3701

Moderately 

toxic Ernst et al., 19931

Freshwater 

Invertebrates Acute Water Flea 

Daphnia magna 

48 h EC50 = 26,000 μg/L 

SDS-3701 Slightly toxic Killeen et al., 19772

(MRID 00030394) 

Vascular 

Plant -- Duckweed Lemna gibba No data available 

Non-vascular 

plant -- 

Green Alga 

Selenastrum 

capricornutum 

EC50 = 33,700 μg/L SDS3701 NA Ernst et al 1993 

Mammals 

Acute Oral Rat 

Rattus norvegicus 

LD50 = 242 mg/kg-bw 

SDS-3701

Moderately 

toxic MRID 00001098 

Chronic 

Repro 

Rat 

R. norvegicus 

1-Generation repro 

3-Generation repro 

NOAEL = 6 mg/kg-bw 

(120 mg a.i./kg-diet) 

SDS-3701 No LOAEL 

NOAEL = 6.25 mg/kg-bw 

(125 mg a.i./kg-diet) 

SDS-3701 No LOAEL 

NA 

MRID 00127845 

MRID 00127844 

Birds 

Acute Oral Mallard Duck 

Anas platyrhynchos 

LD50= 158 mg/kg–bw 

SDS-3701

Moderately 

toxic MRID 00030395 

Subacute 

dietary 

Mallard Duck 

A. platyrhynchos 

LC50= 2000 mg a.i./kgdiet SDS-3701 Slightly toxic MRID 00115108 

Bobwhite quail 

Colinus virginianus 

LC50= 1746 mg a.i./kgdiet SDS-3701 Slightly toxic MRID 00115109 

Chronic 

Repro 

Mallard Duck 

A. platyrhynchos 

NOAEC = 50 mg a.i./kgdiet 

SDS-3701 

LOAEC = 100 mg/kg

N/A MRID 40729402 
56 

Taxon Exposure 

Duration 

Most Sensitive 

Species Tested Toxicity Value 

Acute 

Toxicity 

Category 

Source 

SDS-3701 

Bobwhite quail 

C. virginianus 

NOAEC = 100 mg a.i./kgdiet SDS-3701

LOAEC = 250 mg a.i./kgdiet SDS-3701

N/A MRID 40729404 

Terrestrial 

Invertebrates Acute Honey Bee 

Apis mellifera No Data for SDS-3701 -- -- 

Terrestrial 

plants N/A N/A No Data for SDS-3701 -- -- 

1 Due to reporting deficiencies in the available document, these values should only be used qualitatively. 

 

Effects to Aquatic Organisms 

Freshwater Invertebrates - Acute Exposure Studies

Chlorothalonil (TGAI, Parent)

An open literature study (Davies et al., 1994) reported 96-hour LC50 values for two invertebrate 

species that were more sensitive to chlorothalonil than daphnids (48-h EC50 of 54 μg a.i./L). 96-

hour LC50 values for the giant freshwater crayfish (Astacopsis gouldi) and the freshwater atyid 

shrimp (Paratya australiensis) were 12 μg a.i./L and 16 μg a.i./L, respectively. Details of the 

study were not reported in the article such as potential prior pesticide exposure of the wild caught 

P. australiensis, the five test concentration levels, and control survival performance. Finally, the 

invertebrates in the study were fed crumbled commercial salmon food which may be an adequate 

substrate for chlorothalonil to bind (log Kow 3.8); therefore, the bioavailability of the test 

compound is an uncertainty. 

The technical grade study on the water flea (MRID 45710221) indicated a 48-hour EC50 of 54 μg 

a.i./L based on immobility of the test organisms. Cumulative immobility was 0% in the negative 

and solvent control groups, and 0, 0, 5, 5, 40, 100, 95, 100, and 100% in the mean-measured 

concentration 5.1, 9.3, 16.9, 31.6, 51.5, 95.2, 169.5, 286.7, and 491.6 μg a.i./L test groups. Given 

the uncertainty in the open literature study (Davies et al. 1994) endpoints, this latter study would 

provide the next most sensitive and valid endpoint for use in risk estimation. In all cases, the 

technical grade active ingredient of chlorothalonil is considered very highly toxic to freshwater 

invertebrates. 

OCSPP guideline spiked-sediment toxicity tests for freshwater and estuarine/marine sedimentdwelling organisms to address exposure from both water and sediment are not available. A 28-

day whole sediment spiked-water study, which followed OECD 219 guidance, with Chironomus 

riparius is available but has not been formally reviewed (MRID 45425801). In this study, 

chlorothalonil was applied at test initiation to the overlying water; the OECD guideline is 

reflective of a single spray drift or run-off event exposure scenario. According to the study 

author, residues of chlorothalonil were found in pore water and sediment [concentrations not 

reported] from the highest test concentration (0.5 mg/L) at 24 hour and 7 days and in the 

sediment at 28 days. Also, at this high test concentration, 0.5 mg/L, there was 0% emergence 

after 28 days with the next lower concentration results comparable to the control. The study 
57 

provides evidence that chlorothalonil is toxic to sediment-dwelling organisms in a watersediment test system. Chronic sediment toxicity testing of midges should include an evaluation 

of reproduction, as well as survival, emergence, and growth. The OECD 219, OCSPP 850.1735 

and OCSPP 850.1740 do not evaluate reproduction and are considered short-term or sub-chronic 

tests. 

Based on the guidance outlined in 40 CFR Part 158 for sediment organism testing, chlorothalonil 

meets the requirements for sediment testing: Kow ≥ 3; Kd ≥ 50 and Koc ≥1000. An evaluation of 

the persistence of chlorothalonil in soil indicates representative half-lives range from 1 day to 

243 days (aerobic soil metabolism) and that the transformation rate is application rate dependent. 

Based on the data presented in Table 8, the half-life value for the currently approved maximum 

chlorothalonil application rate is likely between 18-35 days; however, additional data are being 

requested to confirm this assumption. Aerobic aquatic representative half-life values are 

generally less than 10 days based on total system (water and sediment). For the aerobic aquatic 

studies, chlorothalonil is added to the water column, and as chlorothalonil may enter aquatic 

systems via runoff through sorbtion to soil particles, there is uncertainty in the rate of 

chlorothalonil dissipation in the water-sediment system. Chlorothalonil is expected to reach 

aquatic environments from spray drift, as well as leaching and runoff, and based on its use 

patterns, it has the potential to reach both freshwater and estuarine/marine environments. As the 

fate studies suggest that chlorothalonil may dissipate in the aquatic environment under aerobic 

conditions, it is requested that the 10-day whole sediment toxicity studies be conducted 

following OPPTS 850.1735 and 850.1740 guidelines. It is also requested that studies be 

conducted on freshwater organisms, Chironomus tentans and Hyallela azteca, as well as the 

recommended estuarine/marine organism, Leptocheirus plumulosus. However, since 

chlorothalonil may be persistent in terrestrial environments, based on the aerobic soil metabolism 

data, and is expected to enter aquatic environments through runoff, this runoff may provide a 

more chronic or pulsed exposure to sediment organisms. Therefore, it is recommended that after 

the 10-day studies along with the requested environmental fate data are submitted and reviewed, 

if there is evidence that chronic toxicity testing is warranted (based on observed toxicity and 

persistence in the 10-day studies and modeled chronic EECs), then chronic testing will likely be 

requested. Chronic testing would evaluate reproduction as well as survival and growth; 

additionally emergence for midge species. 

End-Use Product (TEP, Formulation)

The conventional end-use product, Bravo 720 (54% a.i.), was tested on the water flea at the 

following mean-measured test concentration levels: 50, 91, 160, 260, and 420 μg form/L 

(equivalent to 27, 49, 86, 140, and 227 μg a.i./L). This study (MRID 42433806) indicated an 

EC50 of 97 μg a.i./L based on immobility (equivalent to mortality) of the test organisms, whereby 

the mean cumulative immobility at 48-hours was 0% in the negative control group, and 0, 0, 30, 

95, and 100% in the respective tested concentrations. As in the case of the technical grade active 

ingredient, the end-use product is also considered to be very highly toxic to freshwater 

invertebrates. 

SDS-3701 (Degradate)
58 

The chlorothalonil degradate, SDS-3701, appears to be considerably less toxic than parent 

chlorothalonil as either technical grade or end-use product to freshwater invertebrates. The 48-

hour LC50 in the water flea was 26,000 μg a.i./L (MRID 00030394) based on mortality of the test 

organisms, whereby average percentage mortality was 0, 7, 27, 87, 80, and 100% in the nominal 

test concentrations 10,000, 15,000, 22,000, 32,000, 46,000, 68,000, and 100,000 μg a.i./L. An 

acetone solvent was used; the negative and solvent controls had 0% mortality at 48-hours. As 

these values are based on nominal concentrations, and the degradation of SDS-3701 in water is 

not known, there is uncertainty in what the actual exposure concentrations were. 

Freshwater Invertebrates - Chronic Exposure Studies

Chlorothalonil (TGAI, Parent)

A chronic study using the parent chlorothalonil as the test substance yielded an overall 21-day 

survival-based NOAEC of 0.6 μg a.i./L (MRID 45710222) with the water flea. The LOAEC in 

this study was 1.8 μg a.i./L, which was based on increased mortality. After 21 days of exposure, 

cumulative adult mortality/immobility was 7% for both control groups (acetone and negative), 

and 5, 25, 40, 55, and 60% in the mean-measured concentrations <0.0001 (<limit of detection, 

solvent control), 0.60, 1.8, 5.8, 19, and 75 μg a.i./L, respectively. There was a significant 

inhibitory effect on reproduction (number of live young/adult) at the 75 μg a.i./L test level. The 

total number of live young produced per adult was ≥40 for the control through 19 μg a.i./L test 

groups, and was 31 for the 75 μg a.i./L group. No dead young were observed during the study in 

any test group, and the number of unhatched eggs per adult was <1 for all control and test 

groups. Terminal growth measurements were not performed. 

However, chlorothalonil was unstable under the static renewal conditions employed in this test, 

declining to less than the level of detection to 62% of nominal concentrations in expired test 

media. Because chlorothalonil concentrations declined to less than the level of detection at the 

lower concentrations, there is considerable uncertainty in the chlorothalonil levels associated 

with toxic effects in this study. Thus, the study was classified supplemental. Furthermore, the 

most sensitive endpoint, survival, for this study was derived on the basis of biological 

significance and not statistical significance. The study was conducted as a static renewal with 

non-detection levels accounted for in the concentration estimates and represented as a value of 

zero (i.e., the compound was unstable between media renewal intervals but the decline of 

chlorothalonil in the water column could not be determined as concentrations were only 

measured at the beginning and end of a renewal period). 

As there is uncertainty in the mean measured test concentrations, given that chlorothalonil 

dissipated during the renewal periods, there is uncertainty if the NOAEC value accurately 

reflects the actual exposure concentrations. However, it is determined that the observed mortality 

effect is treatment related and the reported NOAEC value will be used in the risk estimation 

calculation. However, a second chronic Daphnia study with a higher reported NOAEC will be 

used to characterize risk to freshwater aquatic invertebrates. The second chronic study utilized a 

flow-through test design and parent chlorothalonil as the test substance; the water flea study 
59 

yielded a 21-day NOAEC of 39.5 μg a.i./L (MRID 00115107) based on both survival and 

cumulative number of offspring produced per female. 

Estuarine/Marine Invertebrates - Acute Exposure Studies

Chlorothalonil (TGAI, Parent)

Significant reductions in shell deposition were observed in the eastern oyster study (MRID 

00138143) for the six measured concentrations tested (ranging 0.6 – 30.8 μg a.i./L), yielding a 

96-hr EC50 of 3.6 μg/L (95% CI of 2.9 – 4.3 μg a.i./L). Chlorothalonil is considered very highly 

toxic to estuarine-marine mollusks. 

On the basis of mortality in the 96-hour study (MRID 00127864) conducted on the pink shrimp 

(Penaeous duorarum), the 96-hr LC50 was 165 μg/L. Chlorothalonil is considered highly toxic 

to estuarine-marine shrimp. 

As described above, spiked-sediment data for estuarine/marine sediment organisms are not 

available but are requested. 

End-Use Product (TEP, Formulation)

The single study on a conventional pesticide formulated product (Bravo; 75% a.i.) and 

dungeness crab larvae (Cancer magister) was an open literature study (MRID 00127865), which 

was deemed supplemental as it provided some useful information; however, due to missing 

information on dose concentrations and possible control contamination, the study is reclassified 

to unacceptable and will not be used further in the risk assessment.

Estuarine/Marine Invertebrates - Chronic Exposure Studies

Chlorothalonil (TGAI, Parent)

A mysid shrimp (Americamysis bahia formerly called Mysidopsis bahia) chronic toxicity test 

(MRID 42433807) that may be reported in previous risk assessments was re-evaluated for 

registration review. A recalculation (Dunnett’s test) of the endpoints for this study using the 

current methodology of using the negative control yielded a significant difference at every 

concentration level and a non-definitive NOAEC of <0.65 μg a.i./L. On this basis and additional 

issues with the study, this study has been re-classified to unacceptable and a new study is 

requested at this time. 

Freshwater Fish - Acute Exposure Studies

Chlorothalonil (TGAI, Parent)

There are several acute freshwater fish toxicity studies available. The reported 96-h LC50 values 

for freshwater fish range from 10.5 to 120 μg a.i./L. For the study with the most sensitive 96-h 

LC50 value of 10.5 μg a.i./L using rainbow trout, a co-stressor of reduced oxygen (ca. 50% of 
60 

saturation) was used in the study (Ecotox 87454;7055); therefore, this study was deemed not 

appropriate for use in the risk estimation (risk quotient) evaluation. However, it will be used 

during the risk description/characterization of chlorothalonil for freshwater fish. The second 

most sensitive study, which also used rainbow trout, reported a 96-h LC50 value of 18 μg a.i./L 

and this value will be used to calculate the risk quotient (MRID 45710219). In this study, 

swimming and/or hanging at the surface, lethargy, loss of equilibrium, and/or moribundity were 

observed in surviving fish from the ≥17.7 μg a.i./L groups; effects were first observed within 6 

hours of exposure and continued through 96 hours in groups with surviving fish. The observed 

NOEC (for mortality and sub-lethal effects) was 8.5 μg a.i./L. 

A 96-hour fathead minnow (4-8 day old larvae) LC50 value was also conducted in the fathead 

minnow chronic life-cycle study (discussed below) and was reported to be 23 μg/L by the study 

authors. This value was calculated using mean measured concentrations during a 35 day testing 

period in which the first sample was collected on Day 6. The 96-h LC50 value was recalculated 

(using Toxanal) using the reported 35 day mean measured concentrations for a 96-hour value of 

16 μg/L. As there is uncertainty in the LC50 value due to the uncertainty in the actual exposure 

concentrations during the 96 hour period, the reported 96 hour value for the rainbow trout above 

will be used as the acute endpoint for the assessment (18 μg a.i./L) which is very close to the 

calculated fathead minnow value. 

End-Use Product (TEP, Formulation)

Laboratory acute toxicity studies with freshwater fish for conventional pesticide chlorothalonil 

formulations are available. The formulations tested include: Bravo W-75 (75% a.i.) and Bravo 

720 (54% a.i.). MRIDs 00087304, 00087303, and 00087258 (Bravo W-75 (75% a.i.) were 

considered in the 1999 RED; however, as part of the registration review process they were reevaluated. These studies were conducted as static test systems, did not report if a dilution water 

control group was used, and the results were based on nominal concentrations, and as such these 

studies are now classified as unacceptable. For MRIDs 43302101 and 42433804, the test system 

was flow-through and the results were based on mean measured concentrations. The LC50 values 

range from 49 to 61 μg/L (26 – 33 μg a.i./L) and are presented in Table 13. 

In the paper by Ernst, 1991 (MRID 44286001), for the formulation, Bravo 500 (40% a.i.), the 96 

hour LC50 for the three-spine stickleback was <73 μg a.i/L (183 μg/L formulation; measured 

concentration); mortality on individual test concentrations was not available. For rainbow trout, 

the 96 hour LC50 was 69 μg a.i./L (173 μg/L formulation; nominal) using Bravo 500, and this 

value was not statistically different (p<0.05) from that of the technical (76 μg a.i./L, nominal). 
61 

Table 13. Acute Toxicity for Freshwater Fish for Chlorothalonil Conventional Use 

Formulations 

Test Species % a.i. 

(Formulation)

LC50 μg/L 

Formulation

Citation 

(MRID #)

Toxicity 

Category1

Rainbow trout 54 

(Bravo 720) 61 (33.2 μg a.i./L) 43302101 very highly 

toxic 

Bluegill 54 

(Bravo 720) 49 (26.3 μg a.i./L) 42433804 very highly toxic 

Rainbow trout 40 

(Bravo 500) 173 (69 μg a.i./L 

Ernst et al., 

1991 

(44286001) 

highly toxic 

Three-spined 

stickleback 

40 

(Bravo 500) <183 (< 73 μg a.i./L) 

Ernst et al., 

1991 

(44286001) 

highly toxic 

1

based on formulated product 

Additional data have also been submitted by the registrant regarding toxicity of a multi-a.i. 

formulation (chlorothalonil and penthiopyrad) to a variety of non-target terrestrial invertebrates. 

These will be reviewed and evaluated to determine potential use in the ecological risk 

assessment. 

SDS-3701 Degradate

SDS-3701 acute toxicity tests with bluegill sunfish are available. For both MRID 00029415 and 

00030393, the 96-h LC50 values of 45,000 and 15,000 μg/L, respectively, are uncertain as 

dissolved oxygen was not measured in all treatments, some of which had significant mortality; 

where dissolved oxygen was measured it was less than 60% of saturation during some period of 

testing. Therefore, the potential co-stressor of low oxygen may have been present during both of 

these studies which may have influenced the toxicity and renders the reported LC50 values 

unreliable. Although the co-stressor of low dissolved oxygen makes it difficult to interpret 

whether the observed mortality was attributed to chlorothalonil or to the low dissolved oxygen, it 

appears that SDS-3701 is less toxic than parent chlorothalonil to freshwater fish. For MRID 

00030393, at a nominal concentration of 6,000 μg/L where the dissolved oxygen was 8% of 

saturation at 96 hours, there was no observed mortality with the bluegill. Another study 

conducted with bluegill reported a 96 hour LC50 of 9,200 μg a.i./L (Ernst, 1993); however, 

control performance and a summary of mortality in the treatment groups as well as measured 

concentrations were not reported and as such this study will be used qualitatively. However, 

additional studies with SDS-3701 are not requested at this time. 

Freshwater Fish - Chronic Exposure Studies

Chlorothalonil (TGAI, Parent)

A chronic toxicity test for chlorothalonil with fathead minnow was available (MRID 00030391). 

The study authors reported NOAEC was 3.0 μg/L based on significantly reduced number of eggs 

per spawn and hatchability of F1 eggs at 6.5 μg/L. The study authors performed statistics on 

number of eggs/spawn; however, a decrease in the total number of spawns and eggs was 

observed in the 3.0 μg/L compared to the control. The number of eggs per female in the negative 
62 

control was 494 whereas it was 103 in the 3.0 μg/L group; however, because there is inherent 

variability in egg production and the use of only two replicates, this decrease (79% difference) 

was not significant. However, the decrease is thought to be biologically significant and 

treatment-related and therefore, the NOAEC is 1.4 μg/L where the number of eggs per female 

was 459. The report did not indicate if the test solutions were adjusted for purity (96%), 

therefore, the 1.4 μg/L value was adjusted for purity and the NOAEC to be used in the risk 

assessment is 1.3 μg a.i./L. During this study, all of the fish in the solvent control replicate A 

died between day 16 and 33 due to microbial buildup which could not be controlled. Fish from 

solvent control B were placed in replicate A and these fish were carried out through the 

remainder of the study; in addition, the hatching success for solvent control replicate A was 

significantly less than the negative control due to several early egg spawns that did not hatch. 

Given this mortality and the use of two replicates that diminished the ability to detect significant 

differences, this study is re-classified as Supplemental but a new study is not requested at this 

time. 

Chronic toxicity tests with the degradate SDS-3701 were not available. 

Estuarine/Marine Fish Acute and Chronic Exposure Studies

Chlorothalonil (TGAI, Parent)

For estuarine/marine fish, a sheepshead minnow study was available with a reported LC50 of 33 

μg/L (MRID 00127863). This study was conducted using 3-7 day old larvae. Sublethal effects 

were not reported but there was no mortality reported at 30 μg/L. The study was conducted using 

‘whole material’ and the purity of the material was not reported. The LC50 was recalculated using 

the current EFED model (Toxanal, June 12, 2009). This study was conducted using a static 

system without measuring the test concentrations and as such there is uncertainty in the actual 

exposure chlorothalonil concentrations. This uncertainty is significant given that for several 

other studies conducted with chlorothalonil, maintaining nominal concentrations was difficult 

even under flow-through conditions (MRID 45710219; 00030391). This study has been reclassified as Supplemental and for qualitative use only. As such a new acute study with 

sheepshead minnow in which the test concentrations are monitored is requested. 

A chronic toxicity test for an estuarine/marine fish species is not available and as a result this 

study is considered to be a data gap. Based on the chlorothalonil conventional agricultural use 

map in Figure 3, chlorothalonil may potentially be present in estuarine/marine environments, 

especially in the Southeast. As there is uncertainty in the acute LC50 value for sheepshead 

minnow, and there are problems with calculating a fish acute-to-chronic ratio to extrapolate a 

chronic value for the sheepshead minnow—in the absence of data chronic risk to 

estuarine/marine fish will be assumed. The only fish species with both an acute and chronic 

value was the fathead minnow, but given the exposure uncertainties in the both the fathead 

minnow acute LC50 value and NOEC from the chronic study, using an ACR derived from these 

values is not reliable. 
63 

Aquatic-phase Amphibians

In the paper by McMahon et al., 2011 toxicity of chlorothalonil to amphibians was evaluated. 

This study evaluated mortality in three different species of frogs. This paper will be considered 

for potential use in the risk assessment. 

Aquatic Plants

Chlorothalonil (TGAI, Parent)

A chlorothalonil toxicity test with the aquatic vascular plant, Lemna gibba, is available and the 

7-day EC50 value is 640 μg a.i./L, based on dry weight (MRID 44908102). The NOAEC is 290 

μg a.i./L. The original review compared the chlorothalonil treatment groups to the pooled 

controls; therefore, dry weight endpoint was re-analyzed using the current methodology of using 

the negative control. In addition, the study authors reported toxic symptoms as discolored 

leaves, reduced root growth, and small frond size in concentrations of 71 μg/L and higher from 

Day 2 onward. By the end of the experiment, similar symptoms were observed at the two lowest 

concentrations, 17 and 35 μg/L. 

Several non-vascular toxicity tests using chlorothalonil are available. The most sensitive 5-day 

EC50 endpoint values for the freshwater (Navicula pelliculosa) and marine diatom (Skeletonema 

costatum) were similar with values of 12 and 14 μg a.i./L, respectively (MRID 44908105; 

44908103). A green algae, Selenastrum capricornutum, 5-day EC50 value was 190 μg a.i./L 

(MRID 42432801). In the original review of these studies, the treatment groups were compared 

to a pooled control or solvent control and only the endpoint of cell density was analyzed. 

Therefore, cell density was re-analyzed using a comparison to the negative control and the 

additional endpoints of area under the curve, growth rate, and yield were analyzed. Prior to this 

problem formulation, the study with Anabaena flos-aqua was deemed unacceptable due to higher 

than recommended starting cell density which may have had an impact on the study. Upon 

further review, growth in this study was deemed acceptable and therefore this study is upgraded 

to Acceptable (MRID 44908104). As stated above, the cell density was re-analyzed as well as 

the additional endpoints. An additional green algae study was available in the open literature and 

the reported EC50 value was 6.8 μg a.i./L (Mezcua et al., 2002; Ecotox 80359). This study 

utilized the Algaltoxkit which is reported to be a miniaturized assay that uses ‘algal beads’, 

which can be stored for long periods of time, as the initial source of the algal cells. The assay is 

performed in disposable spectophotometric cells of 10 cm path length, which are used as test 

vessels and analytical containers. This assay is reported to basically adhere to the ISO 8692 

norm and the OECD 201 Test Guideline27. Since this study design seems to deviate substantially 

from the OPPTS 850.5400 guideline, this study, while reporting the most sensitive algal endpoint 

these results will only be used qualitatively. 

SDS-3701 (Degradate)

 

27 http://www.microlan.nl/uploads/files/qaqc/intercalibration_exercise_onthe_algal_toxicity_toxkits.pdf?phpMyAdmin=90a1592554ecf76ebe7c76e2d531280f (accessed December 13, 2011). 
64 

A green algae (Selenastrum capricornutum) study with SDS-3701 was available with a reported 

EC50 value of 33,700 μg a.i./L (Ernst et al., 1993). Details on the methodology were not 

provided in the report as well as a summary of the cell counts therefore this study will be used 

qualitatively. However, additional data is not requested at this time. 

Conventional Use Pesticide Field Studies 

In the paper by Ernst, 1991 (MRID 44286001), spraying of ponds at 875 g a.i./ha (0.78 lb a.i./A) 

resulted in mortality of caged water boatmen (Sigara alternate) and threespine stickleback 

(Gasterosteus aculeatus) which could be related to chlorothalonil exposure. However, caddisfly 

larvae (Limnephilus spp.), freshwater clams (Psidium spp.), water beetles (Haliplus spp.), scud 

(Gramarus spp.) and midge larvae (Chironomidae) did not suffer substantial chlorothalonilinduced mortality. Changes in endemic benthic invertebrate abundance after sprays were not 

remarkable or related to treatment. Faunal impacts on the pond were generally of smaller 

magnitude than were predicted by bioassay results. Factors such as dilution, adsorption to 

suspended particles and microbial degradation are thought to have attenuated the initial pond 

concentrations of chlorothalonil, thereby reducing the toxicity. 

A field study was conducted in which Bravo 500 was applied 3 times to soybeans adjacent to an 

experimental and control pond (MRIDs 00071552, 00127862) and was preliminarily reviewed 

for Registration Review. However, after treatment, maximum residues were 0.6 ppb and 1.1 ppb 

in the experimental and control pond water, respectively. The highest residues found in sediment 

were 51 ppb and 31 ppb in the experimental pond and control pond, respectively. As 

chlorothalonil was detected in the control pond, this study is deemed invalid. 

An additional mesocosm study, Ashwell, 2002 (MRID 46047304) is available and will be 

reviewed. 

Effects to Terrestrial Organisms 

Birds

Chlorothalonil (TGAI, Parent)

One avian acute oral toxicity study is available for chlorothalonil exposure to Mallard duck 

(Anas platyrhynchos) (MRID 00068753). There were no mortalities observed during the study 

and the LD50 value was determined to be greater than 4,640 mg/kg-bw (the highest concentration 

tested). Chlorothalonil is, therefore, classified as practically non-toxic to birds on an acute oral 

basis. The LOAEC in this study was determined to be 2,150 mg a.i./kg-bw based on reduced 

body weight. 

Avian subacute dietary toxicity studies have been submitted for Northern bobwhite quail 

(Colinus virginianus) (MRID 00030388) and mallard duck (MRID 00039146). There were no 

mortalities at any exposure level for either the bobwhite quail or the mallard duck, and therefore 

the LC50 values are greater than 10,000 mg a.i./kg-diet and greater than 21,500 mg a.i./kg-diet, 

respectively. Chlorothalonil is, therefore, classified as practically non-toxic to birds on a 

subacute dietary basis. In the bobwhite quail study, there was a slight reduction in body weight 
65 

at the highest concentration tested (10,000 mg a.i./kg-diet) and in the mallard study there was 

reduced weight gain starting at the 4,600 mg a.i./kg-diet concentration. 

The most sensitive avian reproduction toxicity study submitted for chlorothalonil was conducted 

using bobwhite quail (MRID 45710218). The results of this study were not included in the 

chlorothalonil RED, because it was not submitted to the Agency until after the RED was 

completed (however, it has been used in subsequent risk assessments). A NOAEC of 153 mg 

a.i./kg-diet and a LOAEC of 624 mg a.i./kg-diet were found, based on a reduced number of 14-

day old survivors per hen (and the related endpoint of reduced number of eggs laid per hen). 

Although the endpoints were not statistically significantly different than the controls, the 

differences were considered biologically significant (there was an 18% reduction in the number 

of 14-day old survivors/hen and a 34% reduction in the number of eggs laid/hen at the 624 mg 

a.i./mg-diet concentration when compared to the controls). 

SDS-3701 (Degradate)

SDS-3701 has been shown to be considerably more toxic than chlorothalonil to birds on an acute 

basis. The most sensitive LD50 and LC50 of 158 mg/kg-bw (mallard duck) and 1746 mg a.i./kgdiet (northern bobwhite quail), respectively, will be used to calculate RQs for the degradate 

(MRIDs 00030395 and 00115109, respectively). Available avian reproduction studies using 

SDS-3701 indicates that SDS-3701 is more toxic to bird reproduction than parent chlorothalonil. 

In mallard ducks and bobwhite quail, the NOAECs for SDS-3701 are 200- and 1.5-fold lower, 

respectively, than NOAECs for chlorothalonil. The NOAEC for mallard ducks and SDS-3701 is 

50 mg a.i./kg-diet (the LOAEC is 100 mg a.i./kg-diet based on reduced egg-shell thickness; there 

were also the following effects noted at 250 mg a.i./kg-diet – reduced adult body weight, food 

consumption, number of eggs laid, hatchability, and hatchling survival) (MRID 40729402). The 

NOAEC for bobwhite quails and SDS-3701 is 100 mg a.i./kg-diet (the LOAEC is 250 mg 

a.i./kg-diet based on reduced number of eggs laid and hatchling survival) (MRID 40729404). 

Mammals

Chlorothalonil (TGAI, Parent)

Chlorothalonil is practically non-toxic to mammals [rat (Rattus norvegicus)] on an acute oral 

basis (LD50 >10,000 mg/kg-bw, MRID 00094940). Reproductive impairment was not observed 

in two 2-generation reproduction toxicity studies with rats (R. norvegicus) (MRIDs 41706201, 

45710209) at the highest chlorothalonil levels tested (3000 mg a.i./kg-diet, approximately 230 to 

250 mg/kg-bw). The most sensitive NOAEL = 1,200 mg a.i./kg-diet (LOAEL = 3,000 mg 

a.i./kg-diet, based on decreased body weight gain in parents and offspring) (MRID 45710209). 

SDS-3701 (Degradate)

The degradate, SDS-3701, is more toxic than chlorothalonil with an LD50 of 242 mg/kg-bw, 

which classifies SDS-3701 as moderately toxic to mammals (rat) (MRID 0001098). SDS-3701 

was studied in a 1-generation and a 3-generation rat reproduction toxicity studies (MRIDs 

00127844 and 00127845, respectively). No reproductive impairment occurred in these studies 

up to the maximum dose tested of approximately 6 mg/kg-bw (120 – 125 mg a.i./kg-diet). 
66 

Terrestrial Invertebrates

A honey bee acute contact study (formulation was not identified) resulted in honey bee 

LD50>181 μg a.i./bee (MRID 00077759). There was no mention of mortality or sublethal effects 

in the study. Chlorothalonil is, therefore, classified as practically non-toxic to bees. Additional 

data have also been submitted by the registrant regarding toxicity of a multi-a.i. formulation 

(chlorothalonil and penthiopyrad) to a variety of non-target terrestrial invertebrates. These will 

be reviewed and evaluated to determine potential use in the ecological risk assessment. 

Terrestrial Plants

Tier I seedling emergence and vegetative vigor studies are available for chlorothalonil using 16 

lb a.i./acre test concentrations (MRIDs 42433808 and 42433809). These studies were not 

conducted with a typical end-use product (TEP), but were instead conducted using chlorothalonil 

mixed with a solvent (100% acetone). In previous risk assessments it was concluded that Tier II 

testing was not necessary because the highest registered application rate for chlorothalonil was 

22.7 lb a.i./acre and there were no effects ≥ 25% at the 16 lbs a.i./acre concentration. It was 

reported that the most sensitive species in the seedling emergence study (onions) showed an 11% 

reduction in wet weight and the most sensitive species in the vegetative vigor study (soybean) 

showed a 9% reduction in fresh weight. However, upon a re-evaluation of these studies as part 

of the Registration Review process it was determined that these results were based on the pooled 

(solvent and negative) controls instead of the more appropriate negative control. When the 

results are compared to the negative (and not the pooled) control, onion shows an inhibition in 

growth of 26% in the seedling emergence study and cucumber shows a 26% inhibition in growth 

in the vegetative vigor study at the 16 lbs a.i./acre concentration. 

Contaminant toxicity (dioxins and HCB) 

Another possible source of toxicity from the use of chlorothalonil products is the presence of the 

known impurities that result from the manufacturing process. Hexachlorobenzene (HCB), 

dioxin/furan congeners and other possible organochlorine contaminants have been found in the 

chlorothalonil products. The term “dioxins” is used to represent polychlorinated dibenzo-pdioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). There are 210 different congeners 

of dioxins (75 PCDDs and 135 PCDFs); however, only 17 congeners are considered to be of 

toxicological concern (listed in Table 14). For these 17 congeners, evidence is sufficient to 

conclude that a common mechanism of action, involving binding of the chemicals to the aryl 

hydrocarbon receptor (AHR) as the initial step, underlies 2,3,7,8-TCDD-like toxicity elicited by 

these PCDDs, PCDFs, and Polychlorinated biphenyls (PCBs) (Van den Berg et al., 1998, 2006; 

Hahn, 2002). 

Table 14. Dioxin Congeners of Toxicological Concern; Toxicity equivalency factors for 

mammals, birds and fish associated with each isomer are from U.S. EPA 2008b 

Congener* Mammal TEF Bird TEF Fish TEF 

2378-TCDF 0.1 1 0.05 
67 

Congener* Mammal TEF Bird TEF Fish TEF 

12378-PeCDF 0.03 0.1 0.05 

23478-PeCDF 0.3 1 0.5 

123478-HxCDF 0.1 0.1 0.1 

123678-HxCDF 0.1 0.1 0.1 

234678-HxCDF 0.1 0.1 0.1 

123789-HxCDF 0.1 0.1 0.1 

1234678-HpCDF 0.01 0.01 0.01 

1234789-HpCDF 0.01 0.01 0.01 

OCDF 0.0003 0.0001 <0.0001 

2378-TCDD 1 1 1 

12378-PeCDD 1 1 1 

123478-HxCDD 0.1 0.05 0.5 

123678-HxCDD 0.1 0.01 0.01 

123789-HxCDD 0.1 0.1 0.01 

1234678-HpCDD 0.01 <0.001 0.001 

OCDD 0.0003 0.001 <0.001 

*Abbreviations are as follows: TCDD = tetrachlorodibenzodioxin; PeCDD = pentachlorodibenzodioxin; HxCDD = 

hexachlorodibenzodioxin; HpCDD = Heptachlorodibenzodioxin; OCDD = Octachlorodibenzodioxin; TCDF = 

Tetrachlorodibenzofuran; PeCDF = Pentachlorodibenzofuran; HxCDF = Hexachlorodibenzofuran; HpCDF = 

Heptachlorodibenzofuran; OCDF = octachlorodibenzofuran 

Research has been conducted to characterize the toxicities of PCDDs and PCDFs especially 

relative to each other, since these compounds are often present together in the environment. 

Demonstrated toxic effects of 2,3,7,8-TCDD and other similar-acting PCDD, PCDF and PCB 

congeners in fish, birds, and mammals include adverse effects on reproduction, development, 

and endocrine functions; wasting syndrome; immunotoxicity; and mortality in both laboratory 

and field settings (U.S. EPA 2008b). The EPA (U.S. EPA 2008b) and the World Health 

Organization (Van Den Berg et al. 1998 and 2006) have established toxicity equivalency factors 

(TEFs) for dioxins as they relate to mammals, to birds and to fish (Table 14). In the TEF 

approach, the toxicities of individual congeners are related to 2,3,7,8-TCDD, which is the most 

toxic congener of dioxins to animals (U.S. EPA 2008b; Table 14). For each PCDD and PCDF, 

the concentration (or mass) of the chemical is multiplied by its TEF. The sum of the product for 

each PCDD and PCDF represents the toxicity equivalent (TEQ) concentration relative to 2,3,7,8-

TCDD (Equation 1; U.S. EPA 2008b). 

Equation 1. = ∑n

n TEFn TEQ Concentration *

Dioxins, and HCB are both listed under the Stockholm Convention as Persistent Organic 

Pollutants (POPs). These chemicals are persistent, bioaccumulative and subject to long range 

transport. In general, chronic toxicity endpoints for mammals and birds exposed to pesticides are 

expressed in terms of mg pesticide/kg-bw. The toxicity of 2,3,7,8-TCDD is expressed in units of 

ng/kg-bw, which indicates that this chemical is orders of magnitude more toxic than pesticides 

which are typically assessed by OPP. To characterize the risk associated with HCB, the toxicity 

of HCB will be summarized from the scientific literature. The Agency for Toxic Substances and 

Disease Registry (ATSDR), associated with the Center for Disease Control (CDC), 
68 

Toxicological Profile for HCB (ATSDR, 2002) will be used as one source of information in the 

characterization of the toxicity of HCB. 

When using the TEQ approach, the exposure concentration of each dioxin congener is adjusted 

relative to the toxicity of 2,3,7,8-TCDD. 

In 1993, EPA developed a report (interim) on the available data and methods for assessing 

ecological risks associated with 2,3,7,8-TCDD (USEPA 1993). This section summarizes the 

ecological effects data that are described in that report. Because of the low solubility and high 

Koc and Kow values of dioxins, a method for characterizing toxicity based on the concentration 

of dioxin in the organism (tissue-based residues), rather than freely dissolved concentrations in 

the water is used. Therefore, this section will report toxicity data in terms of organism 

concentrations. 

Currently, the toxicity and risk associated with the presence of the contaminant HCB has not 

been fully characterized. However, information from available scientific literature, including the 

Toxicological Profile for HCB (ATSDR, 2002) will be used to characterize the toxicity and 

estimate the risk associated with the presence of HCB as a contaminant of chlorothalonil. 

Fish

Toxicity data are available for several species of freshwater and saltwater fish exposed to 

2,3,7,8-TCDD. A review of the data indicates that the most sensitive life stage is fish fry. 

According to the 1993 EPA report, “[T]here is no definitive evidence of adverse effects in any of 

the fish species tested if accumulation in eggs is less than 34 pg TCDD/g [ng TCDD/kg], the 

highest no observed effect level for trout fry. This likely corresponds to an accumulation in 

parent fish, with lipid content similar to the eggs, of less than 50 pg TCDD/g.” Based on this 

information, the NOAEC for effects of 2,3,7,8-TCDD on fish fry is 34 ng/kg, which corresponds 

to an accumulation in parent fish (who transfer dioxins to eggs) of <50 ng/kg. Effects to fish fry 

survival are expected when concentrations of 2,3,7,8-TCDD in eggs are 50-500 ng/kg, which 

corresponds to concentrations of 75-705 ng/kg in parent fish. Mortality in adult fish is expected 

with body concentrations of 2,3,7,8-TCDD are 1000-15000 ng/kg (USEPA 1993). 

Aquatic Invertebrates

Data are available from toxicity studies where a species of freshwater invertebrates, i.e., the 

cladoceran Daphnia magna, and a snail (Physa sp.) were exposed to 2,3,7,8-TCDD. After 33-d 

exposures, no adverse effects were observed in either species. Concentrations of 2,3,7,8-TCDD 

in the cladoceran and snail were 1,570,000 and 502,000 ng/kg, respectively (Inensee and Jones 

1975; Inensee 1978). These concentrations are based on measured levels of 2,3,7,8-TCDD in 

tissues. 

Aquatic Plants

Data are available from toxicity studies where non-vascular, i.e., algae (Oedogonium cardiacum) 

and vascular, i.e., duckweed (Lemna minor), aquatic plants were exposed to 2,3,7,8-TCDD. 

After 33-d exposures, no toxic effects were observed in either species. Concentrations of 2,3,7,8-
69 

TCDD in duckweed and algae were 30,700 and 2,295,000 ng/kg, respectively, without any 

apparent adverse effects on the aquatic plants (Inensee and Jones 1975; Inensee 1978). These 

concentrations are based on measured levels of 2,3,7,8-TCDD in aquatic plants. 

 

Birds

In 2003, EPA finalized a document summarizing available laboratory and field studies involving 

reproductive toxicity in birds that are exposed to dioxins. A review of available studies indicates 

that exposures of birds to dioxins lead to mortality, deformity and inhibited development in 

offspring (USEPA 2003b). 

In the Great Lakes Water Quality Initiative Criteria for the Protection of Wildlife for 2,3,7,8-

TCDD, USEPA Office of Water (USEPA OW) also identified several studies reporting toxicity 

data involving chronic exposures of birds to 2,3,7,8-TCDD. From these studies, OW selected a 

reproduction study with the ring-necked pheasant (Phasianus colchicus) exposed to 2,3,7,8-

TCDD (Nosek et al. 1992a, 1992b, 1993) to derive the avian wildlife value used for the 2,3,7,8-

TCDD criteria. In this study, female birds were dosed intraperitonieally with 2,3,7,8-TCDD for 

10 weeks at 1.4, 14 and 140 ng/kg-day. As the birds were injected with the chemical which does 

not represent a relevant route of exposure, this study is not appropriate for use in an EFED and 

AD risk assessment. 

Mammals

Chronic toxicity endpoints for mammals exposed to 2,3,7,8-TCDD have been identified by the 

USEPA OW for the Great Lakes Water Quality Initiative Criteria for the Protection of Wildlife 

(USEPA 1995). USEPA OW defined a no observed adverse effect level (NOAEL) of 1 ng/kgbw/day (i.e., 0.001 μg/kg-bw/day or 1x10-6 mg/kg-bw/day) for reproductive effects to mammals 

exposed to 2,3,7,8-TCDD in food. This NOAEL was based on reduced fertility in first (f1) and 

second generation (f2) rats at the lowest observed adverse effect level (LOAEL) of 10 ng/kgbw/day (Murray et al. 1979). 

Ecological Incidents 

Reviews of the Ecological Incident Information System (EIIS, version 2.1) and the Avian 

Incident Monitoring System (AIMS)28 were conducted on Nov. 28, 2011. There are 33 

chlorothalonil incidents reported in the EIIS (see Table 15). The reported incidents occurred 

between 1976 and 2003. In one of the incidents, chlorothalonil was unlikely the cause of the 

incident. Six of the incidents involved misuses or spills. In the remaining 26 incidents, the 

legality of use was either a registered use (5) or undetermined (21) and the certainty index was 

possible (24) or highly probable (2). Of these 26 incidents, 7 involved aquatic animals, 4 

involved terrestrial animals, and 15 involved plant damage. There were no additional incidents 

identified in the AIMS database for chlorothalonil. 

In the risk assessment, the incidents will be further evaluated to determine if the reported 

incidents represent current patterns of use for chlorothalonil. Examples of additional 

 

28 http://www.abcbirds.org/abcprograms/policy/pesticides/aims/aims/index.cfm 
70 

considerations are mitigation (e.g., reduced application rates), product cancellations, and changes 

in use patterns that have occurred since the date of the reported incident(s). 

In addition to the incidents recorded in EIIS and AIMS, additional pesticide incidents are 

reported to the Agency in aggregated incident reports. Ecological incidents reported in aggregate 

reports include those categorized as ‘minor fish and wildlife’ (W-B), ‘minor plant’ (P-B), and 

‘other non-target’ (ONT) incidents. ‘Other non-target’ incidents include reports of adverse 

effects to insects and other terrestrial invertebrates. As of Nov. 28, 2011, there have been 409 

aggregate incidents reported to the Agency from 1995 to 2011 (404 involving plants and 5 

involving animals). These incidents will be assumed to be the result of registered uses unless 

additional information on the aggregate incidents is provided for the risk assessment. 

Table 15. Summary of Incidents Reported in EIIS 

Type Incident ID Year Legality Certainty 

AQUATIC B000637-001 1976 Undetermined Highly Probable 

AQUATIC I000636-014 1984 Undetermined Possible 

AQUATIC B0000-500-15 1989 Registered use Possible 

TERRESTRIAL I000103-008 1990 Undetermined Unlikely 

PLANTS I003377-013 1993 Misuse (accidental) Highly Probable 

AQUATIC I002200-001 1994 Registered use Possible 

AQUATIC I003596-001 1994 Undetermined Possible 

PLANTS I014406-002 1996 Misuse Possible 

AQUATIC I012265-006 1996 Undetermined Possible 

AQUATIC I007372-007 1997 Misuse (accidental) Probable 

PLANTS I014597-011 1998 Registered use Possible 

PLANTS I007340-625 1998 Undetermined Possible 

PLANTS I007340-629 1998 Undetermined Possible 

PLANTS I007340-631 1998 Undetermined Possible 

PLANTS I007340-628 1998 Undetermined Possible 

PLANTS I007340-630 1998 Undetermined Possible 

PLANTS I007340-632 1998 Undetermined Possible 

PLANTS I014597-010 1998 Registered use Possible 

PLANTS I007340-638 1998 Undetermined Possible 

PLANTS I007340-686 1998 Undetermined Possible 

PLANTS I007340-693 1998 Misuse (intentional) Possible 

PLANTS I007340-712 1998 Undetermined Possible 

TERRESTRIAL I013884-010 1998 Undetermined Highly Probable 

TERRESTRIAL I014341-034 1999 Undetermined Possible 

TERRESTRIAL I014341-033 1999 Undetermined Possible 

TERRESTRIAL I013587-012 1999 Undetermined Possible 

PLANTS I009262-115 1999 Undetermined Possible 

AQUATIC I017028-001 2000 Undetermined Possible 

PLANTS I011838-111 2001 Undetermined Possible 

PLANTS I011942-002 2001 Undetermined Possible 

PLANTS I013550-002 2001 Registered use Possible 

TERRESTRIAL/AQUATIC I011988-008 2001 Misuse (accidental) Possible 

AQUATIC I014538-013 2003 Spill Possible 

The shaded incidents will not be considered in the risk assessment because they involve misuses or incidents 

unlikely caused by chlorothalonil. 

Characteristics of Ecosystems Potentially at Risk 
71 

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

to identify specific ecosystems during the development of a nation-wide ecological risk 

assessment. However, in general terms, terrestrial ecosystems potentially at risk from 

conventional pesticide uses 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 from conventional uses include water bodies adjacent to, 

or downstream from, the treated site and might include impounded bodies such as ponds, lakes 

and reservoirs, or flowing waterways such as streams or rivers including all adjacent off-channel 

habitats that are permanently or intermittently connected to flowing waters. For uses in coastal 

areas, aquatic habitat also includes marine ecosystems, including estuaries, embayments, and 

near shore environments. 

Aquatic ecosystems potentially at risk from industrial pressure treated wood use and industrial 

discharge from film preservative manufacturing include those water bodies to which a WWTP 

directly discharges effluent or downstream of the effluent discharge and could include 

impounded bodies such as lakes and reservoirs or flowing waterways such as streams and rivers 

or if the WWTP discharges to the ocean or an estuary, ecosystems affected may include marine 

coastal ecosystems, bays and estuaries. Similarly, aquatic ecosystems potentially at risk from 

wood preservative uses include water bodies adjacent to or nearby the application or use site. 

Such water bodies might include impounded waters such as ponds, lakes and reservoirs, or 

flowing waterways such as streams or rivers including all adjacent off-channel habitats that are 

permanently or intermittently connected to flowing waters. For uses in coastal areas, aquatic 

habitat also includes marine ecosystems, including estuaries, embayments, and near shore 

environments. 

Assessment Endpoints 

Assessment endpoints are defined as “explicit expressions of the actual environmental value that 

is to be protected.” Defining an assessment endpoint involves two steps: 1) identifying the 

valued attributes of the environment that are considered to be at risk; and 2) operationally 

defining the assessment endpoint in terms of an ecological entity (i.e., a community of fish and 

aquatic invertebrates) and its attributes (i.e., survival and reproduction). Therefore, selection of 

the assessment endpoints is based on valued entities (i.e., ecological receptors), the ecosystems 

potentially at risk, the migration pathways of pesticides, and the routes by which ecological 

receptors are exposed to pesticide-related contamination. The selection of clearly defined 

assessment endpoints is important because they provide direction and boundaries in the risk 

assessment for addressing risk management issues of concern. Changes to assessment endpoints 

are typically estimated from the available toxicity studies, which are used as the measures of 

effects to characterize potential ecological risks associated with exposure to a pesticide, such as 

chlorothalonil. For a summary of the aquatic and terrestrial toxicological endpoints for 

chlorothalonil see Tables 10 and 11 in the Ecological Effects section, respectively. 
72 

Conceptual Model 

The conceptual model is a graphic representation of the structure of the risk assessment. It 

specifies the chlorothalonil release mechanisms, biological receptor types, and effects endpoints 

of potential concern. The conceptual models for aquatic and terrestrial exposures from 

conventional use pesticides Figures 5 and 6, respectively. Dashed lines denote exposure routes 

not assessed due to the likelihood of low potential exposure. 

Chlorothalonil, when used as a material preservative surface protectant in joint and dry 

compound for use on wallboard, in accordance with current labels, is not expected to result in 

exposure of non-target organisms. This use is expected to result in no transport of chlorothalonil 

or its major degradates to outdoor environments either at the industrial facilities where it is added 

to the joint or dry compound or during its storage and in-service use. Wallboard is used 

primarily to form the interior of houses or commercial buildings (e.g., drywall, particle board, 

plasterboard, gypsum board). No effect to non-target organisms including Federally-listed 

threatened and endangered species (listed) as well as non-listed species is expected because 

exposure is not expected. 

Potential emission sources of wood preservative treatment facilities are described in detail in the 

OECD (2000) Emission Scenario Document (ESD) for Wood Preservatives Part 1. Of these 

potential sources, the major emission sources identified as likely and complete, given the fate 

and transport properties of chlorothalonil was collection of wastes from various process points 

with subsequent discharge to on-site or off-site waste water treatment plants (WWTPs), leaching 

Figure 7 along with the receptors of concern and the potential attribute changes in the receptors 

due to exposure to chlorothalonil and its major transformation product (SDS-3701). Emissions 

to air during the application process is likely but low as the vapor pressure of chlorothalonil is 

considered negligible (~ 10-7 mm Hg) while volatilization from treated wood would be even 

lower as more chlorothalonil will absorb into the interior of the wood structure and less would 

be at the surface. Bioaccumulation or food chain transfer is considered a potential exposure 

pathway contributing to risk to aquatic and terrestrial biota that ingest aquatic biota because 

chlorothalonil has a fish BCFs greater than 3000 for whole fish (greater than 5500 for ‘nonedible’ portion [while this portion is usually not eaten by humans, it includes soft internal body 

organs such as the liver, guts, etc. and skin that would be ingested by wildlife]) (MRID 

45710224) and the BCF for total chlorothalonil residues is 2660 in mollusk (MRID 43070601). 

Chlorothalonil, added to exterior wood preservative paints, stains, and coatings, when used in 

accordance with current labels, is expected to result in exposure of non-target organisms as 

chlorothalonil and its major transformation products in these consumer products can leach from 

exterior treated surfaces (e.g., wood, concrete, brick) to soil, and treated surfaces can result in 

transport to surface water, and can leach from contaminated soil to groundwater. Potential 

sources and transport mechanisms are depicted in Figure 8 along with the receptors of concern 

and the potential attribute changes in the receptors due to exposure to chlorothalonil and its 

major transformation products of toxic concern. Exposure of nontarget organisms from 

overspray drift is considered a negligible exposure pathway as discussed previously in the 

environmental fate assessment section. Emissions to air during the application process is likely 

low as the vapor pressure of chlorothalonil is considered negligible (~ 10-7 mm Hg) while 
73 

volatilization from treated wood and other surfaces would be even lower as more chlorothalonil 

will be absorbed into the structure and less would be at the surface. Bioaccumulation or food 

chain transfer in the aquatic environment is considered a potential exposure pathway contributing 

to risk to aquatic and terrestrial biota that ingest aquatic biota. 

Figure 5. Conceptual Model for Conventional Pesticide Use Effects on Aquatic Systems 

Stressor

Source

Receptors

Attribute

Change

DCPA applied to use site and associated degradate and impurities

Spray drift

Fish/aquaticphase 

amphibians

**Piscivorous 

mammals and 

birds 

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of 

PCEs

related to prey 

availability

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface water/

Sediment

Runoff

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Uptake/gills 

or integument

Ingestion Ingestion

Long range 

atmospheric 

transport

Wet/dry deposition

Soil Groundwater

Uptake/gills 

or integument

Aquatic Plants

Non-vascular

Vascular

Uptake/cell, 

roots, leaves Riparian plant

terrestrial 

exposure 

pathways

Chlorothalonil applied to use site and associated degradate and impurities
74 

Figure 6. Conceptual Model for Conventional Pesticide Use Effects on Terrestrial Systems 

 

Stressor

Source

Receptors

Attribute

Change

Chlorothalonil applied to use site and associated degradate and impurities

Direct

application Spray drift

Birds/terrestrialphase 

amphibians/

reptiles/mammals

Terrestrial 

insects

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in prey

Modification of

PCEs related to

prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Terrestrial/riparian

plants grasses/forbs,

fruit, seeds (trees,

shrubs)

Runoff

Mammals/ 

birds

Exposure

Media

Soil

Ingestion/ 

inhalation

Ingestion/ 

inhalation

Ingestion/

inhalation

Ingestion

Dermal uptake/Ingestion/

inhalation 

Long range 

atmospheric 

transport

Root uptake

Wet/dry deposition

Terrestrial 

phase 

amphibians

-

Ingestion/ 

inhalation
75 

Figure 7. Conceptual Model of the Transport, Exposure and Effects to Aquatic and 

Terrestrial Organisms from Industrial Treated Wood Product Uses of Chlorothalonil 

Stressor

Source

Receptors 

and 

Exposure 

Routes

Attribute

Change(s)

Dip, Pad or Pressure 

Treated Wood Process 

Facility Drain

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in aquatic plants

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface Water

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Uptake across gills or 

integument and/or sediment 

ingestion

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption by 

cells, roots, leaves, 

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore

/ Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g.,amphibians, mollusks, crustaceans,, etc.)

Ingestion

STP/WWTP

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

Post-Treated Wood 

Product Storage

Leaching and Run-off

In-Use Service of Wood 

Treated Wood Products

Leaching and Run-off

Sediment
76 

Figure 8. Conceptual Model of the Transport, Exposure and Effects to (A) Aquatic and (B) 

Terrestrial Organisms from Use of Chlorothalonil in Consumer Products used Outdoors 

Stressor

Source

Receptors 

and 

Exposure 

Routes

Attribute

Change(s)

Exterior application to wood and wood products or use of antimildew/antimold 

products on exterior surfaces (e.g., paints and coatings for concrete, etc.)

Leaching/Run-off

Individual organisms

Reduced survival

Reduced growth

Reduced reproduction

Food chain

Reduction in algae

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary productivity

Reduced cover

Community change

Modification of PCEs related to 

habitat

Surface water/

Sediment

Overspray

Aquatic Animals

Invertebrates

Vertebrates

Exposure

Media

Ingestion Ingestion

Long range 

atmospheric 

transport

Wet/dry deposition

Uptake across gills or 

integument and/or sediment 

ingestion

Aquatic Plants

Non-vascular

Vascular

Uptake or sorption by cell, 

roots, or leaves, Riparian plant

terrestrial 

exposure 

pathways see 

Figure 8(B)

Piscivorous*

Invertebrates

Vertebrates

Phytoplanktivore/ 

Herbivore

Invertebrates

Vertebrates

*As used here this term refers to animals (terrestrial or aquatic) that eat not just fish but any aquatic animal (e.g.,amphibians, mollusks, crustaceans,, etc.)

Ingestion

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk

(A)

Stressor

Source/ 

Exposure 

Media

Receptors 

and 

Exposure 

Routes

Attribute

Change(s)

Exterior application to wood and wood products or use of antimildew/antimold products 

on exterior surfaces (e.g., paints and coatings for concrete, etc.)

Over Spray

Terrestrial insects

Individual organisms

Reduced survival 

(emergence*)

Reduced growth

Reduced reproduction**

Food chain

Reduction in plant biomass

Reduction in prey

Modification of PCEs 

related to prey availability

Habitat integrity

Reduction in primary 

productivity

Reduced cover

Community change

Modification of PCEs 

related to habitat

Terrestrial plants

Grasses/forbs, fruit, 

seeds, trees, shrubs

Leaching

Terrestrial Animals

Birds (Reptiles, Amphibians)

Mammals

Soil

Ingestion Ingestion

Dermal uptake/ 

Ingestion

Long range 

atmospheric transport

Root uptake

Wet/dry 

deposition

Dermal contact

Contact/Uptake 

leaves, stems

Beneficial 

Insects

Reduced 

survival

*Refers to seedling emergence

**Vegetative vigor and seedling emergence endpoints are assumed to be as sensitive or more sensitive than 

reproduction endpoint and plant reproduction s not explicitely evaluated.

(B)

Key

Most likely

exposure pathway 

contributing to risk

Low likelihood of 

contributing to risk
77 

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 chlorothalonil, the 

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

assessment: 

Conventional Pesticide Uses: 

Chlorothalonil, when used in accordance with current labels, can result in off-site 

movement of the compound via runoff, leaching to groundwater, spray drift and 

atmospheric transport leading to exposure of non-target plants and animals. 

Direct applications to and atmospheric deposition to foliar surfaces may serve as 

a major source of chlorothalonil exposure to wildlife. Exposure in these 

environmental compartments will result in adverse effects upon the survival, 

growth, and reproduction of non-target terrestrial and aquatic organisms. These 

non-target organisms include federally-listed threatened and endangered species. 

Industrial Wood Preservative Uses: 

Chlorothalonil, when used as an industrial wood preservative, in accordance with 

current labels, can result in transport of it and its major transformation products via 

down-the-drain disposal from a wood preservative facility to surface water. Leaching 

and run-off to soil and surface water may occur during storage and/or in-service use of 

treated wood. Exposure in these environmental compartments has the potential to reduce 

survival, growth, and/or reproduction in non-target aquatic organisms, terrestrial nontarget plants, and non-target terrestrial organisms that ingest aquatic animals and 

plants—when used in accordance with the current labels. These non-target organisms 

include Federally-listed threatened and endangered species (listed) as well as non-listed 

species. 

Consumer Product Wood Preservative, and Exterior Building/Construction 

Material Preservative/Surface Protectant Uses: 

Chlorothalonil, when used as a consumer product wood preservative or as a 

surface protectant, in accordance with current labels, can result in transport of it 

and its major transformation products off the in-service use site from leaching 

and run-off to soil and surface water. Exposure in these environmental 

compartments has the potential to reduce survival, growth, and/or reproduction 

in non-target aquatic organisms, terrestrial non-target organisms—when used in 

accordance with the current labels. These non-target organisms include 

Federally-listed threatened and endangered species (listed) as well as non-listed 

species. 

Joint and Dry Compound for Use on Wallboard: 

Chlorothalonil, when used as a material preservative in joint and dry compound 

for use on wallboard, in accordance with current labels, will not result in 

exposure of non-target organisms. This use has no exposure and therefore no 

effect to non-target organisms including Federally-listed threatened and 

endangered species (listed) as well as non-listed species. 
78 

F. ANALYSIS PLAN

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

estimated. The use, environmental fate, and ecological effects of chlorothalonil 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 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 chlorothalonil is estimated using the probit dose-response slope and either 

the level of concern (discussed below) or actual calculated risk quotient value. For down-thedrain risk estimates, an approach that estimates the number of days a concentration-of-concern 

(COC) is exceeded, also referred to as a probabilistic dilution model (PDM) approach may be 

used to assess risk to aquatic organisms. 

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

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

chlorothalonil. 

Measures of Exposure 

Aquatic Exposure

Drinking Water 

Conventional Pesticide Uses

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

assessments of chlorothalonil. The drinking water assessment will incorporate model estimates 

of chlorothalonil and any transformation products of toxicological concern in surface water and 

groundwater. The potential toxicity of chlorothalonil transformation products will be considered 

in the drinking water assessment conducted during the Registration Review process. The final 

determination of the residues of concern will be made through consultation with the Health 

Effects Division (HED) and through any proceedings of the ROCKS (Residues of Concern 

Knowledge Subcommittee). The drinking water assessment will include the modeling results 

discussed in the Drinking Water Exposure Assessment section above and will also include a 

summary of available surface water and groundwater monitoring data. 

The potential toxicity of chlorothalonil transformation products in addition to SDS-3701 will be 

considered in the drinking water assessment conducted during the Registration Review process. 

If degradates of similar toxicity to chlorothalonil are identified as residues of toxicological 

concern a total toxic residue method will be employed to derive EDWCs. To account for total 

toxic residues, each relevant environmental fate study (hydrolysis, aqueous photolysis, aerobic 

soil metabolism, etc.) will be used to calculate the amount of total toxic residues present in each 

study at each sampling interval. If a transformation product was not identified in one of the 

studies it will be assumed to be a toxic residue. The total concentrations at each sampling 

interval will be used to recalculate the rate constant and the corresponding half-life value for 
79 

each study. These data will then be used to calculate modeling input parameters according to the 

current (the time when the assessment is completed) input parameter guidance. When there are 

no data available for the identified or unidentified transformation products, input values will be 

assumed to be equivalent to the parent value. If data are available for both chlorothalonil and the 

transformation products of toxicological concern and the data cannot be combined, the most 

conservative plausible values will be used. This will be based on the assessor’s best judgment. 

Rationales for choosing each input parameter will be discussed in the assessment. If a 

transformation product is identified that has a different mode of toxicity or is substantially more 

toxic than the parent it will be modeled separately if data are available. 

The current models available for conducting drinking water assessment for surface water include 

PRZM (Pesticide Root Zone Model, version 3.12.3, June 2006) and EXAMS (EXposure 

Analysis Modeling System, version 2.98.04.06, April 2005) models. PRZM will be used to 

simulate pesticide transport as a result of runoff and erosion from an agricultural field while 

EXAMS will be used to estimate environmental fate and transport of pesticides in the index 

reservoir. Measures of exposure will be based maximum single and year labeled application 

rates, minimum retreatment intervals, and conservative methods of application. The location of 

the field is specific to the crop being simulated using site-specific information on the soils, 

weather, cropping, and management factors associated with the scenario. The crop/location 

scenario is intended to represent a high-end exposure site on which the crop is normally grown. 

Based on historical rainfall patterns, the receiving water body receives multiple runoff events 

during the years simulated. Weather and agricultural practices are simulated for 30 years so that 

the 10-year exceedances probability at the site can be estimated. The simulation is generated 

using 30 years of meteorological data, encompassing the years from 1961 to 1990. Several 

standard PRZM scenarios are available which will be used to represent each chlorothalonil use. 

If multiple scenarios exist for the same crop the most conservative scenario will be used. If a 

PRZM scenario does not exist for a specific chlorothalonil use and surrogate scenario will be 

used. Generally, the 1-in-10 year peak is used for estimating acute exposures, 1-in-10-year 

annual average is used for assessing chronic exposure, and a 1-in-10 year average is used for 

cancer exposure; however, a distribution of daily concentrations or some other averaging period 

not listed above could be used depending on the exposure duration of concern. 

Currently, groundwater modeling is completed using SCI-GROW (Screening Concentration in 

Groundwater, version 2.3, August 8, 2003); however, PRZM-groundwater [(GW); November 2, 

2011 Prerelease version] is also available to refine groundwater exposure estimates. SCI-GROW 

is an empirical model based on a linear best fit through 13 single-application groundwater 

studies. PRZM-GW can be used to simulate vertical pesticide transport through the soil profile 

into an aquifer following application to an agricultural field. The PRZM scenarios used in 

groundwater simulations are representative of vulnerable sites—shallow unconfined aquifers 

under an agricultural field with leaching prone soil—and output values represent pesticide 

concentrations that may be observed in drinking water resulting from the use of groundwater 

vulnerable to pesticide contamination as source water. The results are expected to represent the 

upper bound values on the concentrations of toxic residues that might be found in drinking water 

supplied by groundwater. 
80 

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. 

Antimicrobial Pesticide Uses

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

of chlorothalonil. The drinking water assessment will incorporate model estimates of 

chlorothalonil in surface water from the industrial wood preservative use. 

The General Population and Ecological Exposure from Industrial Releases module of E-FAST2 

(version 2, August 31, 2009) and the Industrial Releases module will be used to develop 

screening estimates of total toxic residues of chlorothalonil concentrations in drinking water 

sources that are derived from streams and rivers that receive wastewater discharges from a 

facility engaged in industrial uses of wood preservatives. In the absence of appropriate data on 

the percent removal of chlorothalonil and its major toxic transformation products during drinking 

water treatment the Agency will assume there is no removal. 

Spray Drift 

AgDrift will be used to assess the potential spray drift of chlorothalonil to adjacent terrestrial 

habitats or aquatic environments that serve as habitat and source water for drinking water. These 

data will be compared to the Levels of Concern (LOCs) for humans and non-target organisms. In 

addition to the use of spray drift models, as part of the registration review assessment, available 

monitoring data from the open literature and any submitted data will be evaluated to assess the 

potential impacts of spray drift on human health and non-target organisms. Other methods of 

atmospheric transport are possible other than spray drift including volatilization or particulate 

phase transport. 

Volatilization 

While the Agency does not yet have a method for quantitatively assessing long range transport, 

PERFUM can be used to look at vapor phase concentrations of chlorothalonil adjacent to 

application sites. If a long range transport model is available at the time the assessment is 

completed, long range transport of chlorothalonil will be quantitatively assessed. 

Ecological Exposure for Conventional Use Pesticides 

Estimated environmental concentrations of chlorothalonil and other residues of potential 

toxicological concern in surface water will also be calculated using PRZM-EXAMs; however, 

the standard scenarios used for ecological pesticide assessments assume application to a 10-

hectare agricultural field that drains into an adjacent 1-hectare water body that is 2 meters deep 

(20,000 m3

 volume) with no outlet. PRZM/EXAMS is used to estimate screening-level exposure 

of aquatic organisms to chlorothalonil. The measure of exposure for aquatic species is the 1-in10 year return peak or rolling mean concentration. The 1-in-10 year peak is used for estimating 

acute exposures of direct effects to aquatic organisms. The 1-in-10-year 60-day mean is used for 
81 

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

is used for assessing chronic exposure to aquatic invertebrates. As stated in the drinking water 

portion above, the potential toxicity of chlorothalonil transformation products in addition to 

SDS-3701 will be considered as part of the risk assessment process. If degradates of similar 

toxicity to chlorothalonil are identified as residues of toxicological concern a total toxic residue 

method will be employed to derive estimated environmental concentrations (EECs). 

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

to spray drift are derived using the T-REX model (version 1.4.1, 10/09/2008). This model 

incorporates the Kenega nomograph, as modified by Fletcher et al. (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 Kenega 1972). The 

Fletcher et al. (1994) modifications to the Kenega 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. 

Terrestrial exposure to the degradate SDS-3701, which is more toxic to birds and mammals than 

the parent, will be estimated using TREX. The application rate input value will be the maximum 

registered application rate times the maximum percent that the degradate was formed in the fate 

studies (i.e., 34.1%, aerobic soil metabolism studies, MRIDs 00040547 and 00087351). The 

potential toxicity of chlorothalonil transformation products in addition to SDS-3701 will be 

considered as part of the risk assessment process. If degradates of similar toxicity to 

chlorothalonil are identified as residues of toxicological concern for terrestrial organisms then it 

is assumed that these degradates would be accounted for when the EECs are derived by using the 

default 35-day foliar half-life in T-REX (i.e., this is similar to the TTR approach described above 

for the aquatic assessment). 

 

EECs for terrestrial plants inhabiting dry and wetland areas are derived using TerrPlant (version 

1.2.2, 12/26/2006). This model uses estimates of pesticides in runoff and in spray drift to 

calculate EECs. EECs are based upon solubility, application rate and minimum incorporation 

depth. 

In general, deposition of drifting or volatilized pesticides is expected to be greatest close to the 

site of application. The AgDRIFT spray drift model (v2.01; May 2001) is used to assess 

exposures of organisms to chlorothalonil deposited on terrestrial habitats by spray drift. 

Aquatic exposure to the impurities, HCB and dioxins, will be characterized. PRZM/EXAMS 

will be used to estimate screening-level exposure of aquatic organisms to these compounds. 

Terrestrial exposure to HCB and 2,3,7,8-tetrachlorodebenzo-p-dioxin (TCDD) will be estimated 

using TREX, and KABAM, as bioaccumulation is a major transport pathway for these 

chemicals. The application rate input value will be either the maximum allowed amount of the 

impurity in the final formulation or an upper estimate of the amount in the final formulation, 

respectively.

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

upper bound estimate of exposure to wildlife via drinking water using chlorothalonil’s aquatic 
82 

solubility limit (0.8 mg/L), the most sensitive acute and chronic avian toxicity endpoints (mallard 

duck with LD50 >4,640 mg/kg-bw and bobwhite quail NOAEC = 153 mg a.i./kg-diet, 

respectively), and the most sensitive acute and chronic mammalian toxicity endpoints (rat LD50

>10,000 mg/kg-bw, and NOAEL = 92.5 mg a.i./kg-bw, respectively). Drinking water exposure 

alone was determined not to be a potential pathway of concern for parent chlorothalonil for avian 

or mammalian species on an acute basis or chronic basis. For a sample of the output generated 

by SIP v.1.0, please see APPENDIX D. Detailed information about the SIP v.1.0, as well as the 

tool, can be found on the EPA’s website at 

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

SIP was also used to calculate an upper bound estimate of exposure to wildlife via drinking water 

using the estimated aquatic solubility limit for the degradate SDS-3701 (115.7 mg/L), the most 

sensitive acute and chronic avian toxicity endpoints (mallard duck with LD50 = 158 mg/kg-bw 

and NOAEC = 50 mg a.i./kg-diet, respectively), and the most sensitive acute and chronic 

mammalian toxicity endpoints (rat LD50 = 242 mg/kg-bw, and NOAEL = 6 mg a.i./kg-bw, 

respectively). Drinking water exposure alone was determined to be a potential pathway of 

concern for avian and mammalian species on an acute basis and chronic basis. This pathway for 

the degradate will be explored further with the development of SIP v.2.0 in the Ecological Risk 

Assessment for chlorothalonil. Again, for a sample of the output generated by SIP v.1.0, please 

see APPENDIX D. 

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

an upper bound estimate of exposure using chlorothalonil’s vapor pressure (5.7 x 10-7 torr) and 

molecular weight (265.91 amu) for vapor phase exposure as well as the maximum application 

rate (13 lb a.i./acre) and method of application for spray drift. STIR incorporates results from 

several toxicity studies including acute oral and inhalation rat toxicity endpoints obtained from 

the “six-pack” of core studies, which are a series of six guideline studies that are submitted to the 

Registration Division of the Office of Pesticide Programs for technical and formulated products 

of a pesticide [rat acute oral LD50 >10,000 mg a.i./kg-bw and acute inhalation LC50 = 0.012 

mg/L (MRID 43678403), respectively] as well as the most sensitive acute oral avian toxicity 

endpoint (enter avian species with LD50 > 4,640 mg a.i./kg-bw). Based on the results of the 

STIR model, inhalation exposure alone was determined to be a potential pathway of concern for 

avian and mammalian species on an acute basis. 

The inhalation pathway via spray drift of the pesticide is of potential significance. This pathway 

will be explored further by requesting additional toxicity or exposure data (non-guideline acute 

avian inhalation toxicity) that may reduce uncertainty and the incorporation of this data into the 

inhalation risk assessment for birds and mammals. Potential risks from inhalation of the 

chlorothalonil degradate SDS-3701 will be considered in the assessment, but EFED does not 

recommend requesting an avian inhalation study for SDS-3701 at this time. For a sample of the 

output generated by STIR v.1.0, please see APPENDIX E. Detailed information about the STIR 

v.1.0 tool can be found on the EPA’s website at: 

http://www.epa.gov/pesticides/science/models_pg.htm#terrestrial. 
83 

Ecological Exposure for Antimicrobial Use Pesticides 

The tool used to predict aquatic estimated environmental concentrations (EECs) and the number 

of days a COC is exceeded for down-the-drain emissions is the Exposure and Fate Assessment 

Screening Tool (E-FAST2) (version 2, August 31, 2009). For the wood preservative treatment 

process emission scenario, the General Population and Ecological Exposure from Industrial 

Releases module, hereinafter referred to as the Industrial Releases module, will be used to 

develop screening estimates of chlorothalonil and its major transformation toxic residues in 

surface waters as a result of facility drain releases to WWTPs29. Inputs in addition to the 

physical-chemical properties of chlorothalonil and its toxic transformation products include 

information regarding: the percent removal during wastewater treatment; production or use 

volume for the industrial wood preservative use (to help determine the number of facilities); and 

treatment wood preservative facility information, such as number of days of release per year. For 

the physical-chemical properties the Agency anticipates using the available environmental fate 

information from guideline studies for chlorothalonil and its major degradates which are 

summarized in Tables 7 through 9. An Activated Sludge Respiration Inhibition Test (ASRI) and 

one of four biodegradation tests (Ready Biodegradation; Porous Pot; Simulation Test to Assess 

the Biodegradability of Chemicals Discharged in Wastewater Treatment, Test for Biodegradation 

in Activated Sludge; or Simulation Test – Aerobic Sewage Treatment: A. Activated Sludge 

Units) are required to analyze the potential impact of the chemical on the microorganisms in the 

biological treatment processes of a WWTP, and to determine its fate and residue levels in surface 

water receiving effluent discharge. The Ready Biodegradability Test is not an option if the 

median effect concentration (EC50) from the ASRI test is less than or equal to 20 milligrams per 

liter (mg/L); in that case, one of the three simulation tests must be performed. 

Default values for volume of wood treated per day from the emission scenario for wood 

preservatives document (OECD, 2002), the water solubility of chlorothalonil, and label use rate 

will be used to estimate releases to a facility drain in units of kilograms per day (kg/site/day). 

Facility information needed to estimate aquatic exposures from emissions to WWTP from the 

industrial wood preservative process include the following: 

• The number of facilities that treat (dip, spray, or pressure) wood products with 

chlorothalonil; and 

• How many of these facilities have on-site and/or off-site wastewater treatment. 

In the absence of information on the number of facilities that treat wood products with 

chlorothalonil and how many of these facilities have on-site and/or off-site wastewater treatment, 

the Agency will assume that all wood treatment facilities in the United States have the potential 

to use chlorothalonil. 

In the absence of appropriate test data on biodegradation during wastewater treatment, the 

Agency will assume that there is no removal of chlorothalonil and its major toxic transformation 

products during wastewater treatment. 

 

29 http://www.epa.gov/opptintr/exposure/pubs/screen.htm 
84 

The tool used to predict aquatic EECs for leaching and runoff from treated materials (e.g., fence, 

deck, siding, shakes, foundations, etc.) and from contaminated soil at wood preservative facilities 

is expected to be PRZM/EXAMS. A pervious soil, impervious surface, and a combination of 

pervious and impervious surfaces (residential scenario) is expected to be used to bound risks. 

For the physical-chemical properties the Agency anticipates using the available environmental 

fate information from guideline studies for chlorothalonil and its major degradates which are 

summarized in Tables 7 through Table 9. Emission rate of chlorothalonil and its major toxic 

transformation products and impurities of concern is needed for treated materials as input to 

determine loading. 

Measures of Toxicity 

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

Data were obtained from registrant-submitted studies. Also, prior to completion of the risk 

assessment, literature studies identified by ECOTOX will also be incorporated as appropriate. 

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 MidContinent Ecology Division (USEPA 2007d). 

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 to olfaction (relating to the sense of smell) in fish]. 

Quantitative assessments of risks, though, are limited to those endpoints that can be directly 

linked to the Agency’s assessment endpoints of impaired survival, growth and reproduction. 

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

toxicity of chlorothalonil to birds is similar to terrestrial-phase amphibians and reptiles. The 

same assumption is made for fish and aquatic-phase amphibians in the absence of data. If data 

becomes available for these taxa, then it will be evaluated for use in the risk assessment. 

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, the EC25 for 
85 

terrestrial plants and EC50 for aquatic plants is used; for listed plants, either the NOAEC or EC05

is used. 

Measures of Risk 

Previously completed screening level risk assessments and exceedances of Agency levels of 

concern indicate a need to further examine and refine risk to aquatic and terrestrial animal and 

aquatic plant species. Analysis of potential indirect effects on listed species (both aquatic and 

terrestrial) is also required. This analysis plan will be revisited and may be revised depending 

upon the data available in the open literature and the information submitted by the public in 

response to the opening of the Registration Review docket. 

Integration of Exposure and Effects 

Risk characterization is the integration of exposure and ecological effects characterization to 

determine the potential ecological risk from the use of chlorothalonil on use sites listed in Table 

4 for conventional uses and for the registered antimicrobial used listed in Table 5, 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 chlorothalonil risks for 

conventional uses and for antimicrobial uses—except for the down-the-drain analysis, the risk 

quotient (RQ) method is used to compare exposure and measured toxicity values. EECs are 

divided by acute and chronic toxicity values. The resulting RQ values are then compared to the 

Agency’s LOC values (USEPA 2004). These criteria are used to indicate when chlorothalonil’s 

uses, as directed on the label, have the potential to cause adverse direct or indirect effects to nontarget organisms. In addition, incident data from EIIS, aggregate incident reports, and AIMS 

will be considered as part of the risk characterization. As noted previously, where data are 

lacking on the toxicity of chlorothalonil, risk will be presumed. 

For down-the-drain risk estimates for antimicrobial uses, exposure and toxicity information is 

integrated using an approach that estimates the number of days a COC is exceeded, also referred 

to as a probabilistic dilution model (PDM) approach. COC values will be derived for 

chlorothalonil by multiplying the Agency’s presumptive level of concern (LOC) values, which 

are unitless, by the most sensitive endpoint for the relevant receptor group. This allows 

expression of the LOC values in terms of concentration. Calculations used for determining COC 

values are listed in for aquatic animals and plants (see Table 16). 

Table 16. Aquatic Animal and Plant LOC Values and Comparable COC Values 

LOC COC calculations

Aquatic Animals 

 Acute risk 0.5 (LC50 or EC50 ) × LOC

 Acute listed species 0.05 (LC50 or EC50 ) × LOC

 Chronic risk 1 NOAEC × LOC

Aquatic Plants 

 Listed species 1 IC50 × LOC

 Non-listed species 1 NOAECa × LOC a

An IC05 may be used as a surrogate when a NOAEC cannot be determined. 
86 

For a screening level estimate, results are based on a high-end scenario which represents the 

averaged probability of exceedance of 10 percent of wastewater treatment plants (WWTPs) that 

have the highest probability of exceedance of the COC following treatment based on the 

distribution of the ratio of stream flows to wastewater treatment plant flows for the category of 

Standard Industrial Classification (SIC) code that most closely represents wood preservative 

treatment facilities These results are expressed as the number of days per year of exceedance of 

the concentrations of concern determined for key categories of aquatic organisms, including 

freshwater fish, freshwater invertebrates, and aquatic plants. EECs based on the 10th percentile 

WWTP 1Q1030 and 7Q1031 are also provided. After the Agency’s down-the-drain assessment is 

performed, if any of the Agency’s acute COCs for the high-end exposure scenario has a 

probability of being exceeded >4 days/year, or a chronic COC has a probability of being 

exceeded >20 days/year, a potential for adverse effects is presumed.

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 chlorothalonil. 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 area 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. 

When conducting the ecological risk assessment for chlorothalonil 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 chlorothalonil 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 

 

30 Hydrologically-based design flow term describing the lowest one-day average flow that occurs (on average) once 

every ten years. 

31 Hydrologically-based design flow term describing the lowest consecutive seven-day average flow that occurs (on 

average) once every ten years. 
87 

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. 

Endocrine Disruptor Screening Program 

As required under FFDCA section 408(p), EPA has developed the Endocrine Disruptor 

Screening Program (EDSP) to determine whether certain substances (including pesticide active 

and other ingredients) may have an effect in humans or wildlife similar to an 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, and 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. 

 

Between October 2009 and February 2010, EPA issued test orders/data call-ins for the first 

group of 67 chemicals, which contains 58 pesticide active ingredients and 9 inert ingredients. 

This list of chemicals was selected based on the potential for human exposure through pathways 

such as food and water, residential activity, and certain post-application agricultural scenarios. 

This list should not be construed as a list of known or likely endocrine disruptors. 

Chlorothalonil was among the group of 58 pesticide active ingredients that received EDSP test 

orders. For information on the status of the orders issued under the EDSP for each chemical, 

please visit our website at http://www.epa.gov/endo/ and click on the "Status of EDSP 

Orders/DCIs" in the Highlights Box. Additional information on the EDSP, including the policies 

and procedures, the list of 67 chemicals, the test guidelines and the Tier 1 screening battery, can 

also be found at this website. 

G. PRELIMINARY IDENTIFICATION OF DATA GAPS 

Environmental Fate 

Several environmental fate studies have been submitted to support the registration of 

chlorothalonil; however, many of these studies were classified as supplemental or unacceptable. 

For many of the studies, the identification of chlorothalonil transformation products was not 

provided. The status of environmental fate studies for chlorothalonil is presented in Table 17. 
88 

Table 17. Environmental Fate Data Requirement Table for Chlorothalonil

Guideline Description MRID Classification Data 

Gap? Comments 

835.1110 

Activated Sludge 

Sorption 

Isotherm, TGAI 

No data ─ Yes 

To determine extent of partitioning of 

chlorothalonil and its major toxic 

transformation products to biosolids for 

the antimicrobial down-the-drain analysis

835.2120 Hydrolysis 00040539 Supplemental Yes 

No data have been provided on the 

transformation of chlorothalonil under 

basic conditions. Data on the dissipation 

of chlorothalonil at pH >7 (e.g., pH 9) is 

needed. 

835.2410 Soil Photolysis 

00087349 Supplemental No Despite the guideline deviations in these 

studies, little would be gained from 

repeating them—chlorothalonil is 

considered stable 

00040543 Supplemental No 

835.2370 Air Photolysis No data available Yes No data has been provided on the 

photolysis for chlorothalonil in air. 

835.2240 Aqueous 

Photolysis 45710223 Supplemental Yes 

MRID 45710223 was originally classified 

as acceptable; however, after a recent 

review this study was reclassified as 

supplemental because three major 

transformation products (up to 47% AR) 

were not identified. Additional data are 

needed to identify these major 

transformation products and any other 

potentially toxic transformation products 

observed in this study. If this information 

cannot be provided, a new study is 

required. If additional data are not 

provided, these unidentified residues 

would be assumed to be as toxic as 

chlorothalonil or SDS-3701 as part of a 

total toxic residue approach. 

835.3110 

or 

Ready 

Biodegradability, 

TGAI or No data ─ Yes 

The results of the ASRI effects test (GLN 

850.6800 or OECD 209), determine 

which of these biodegradation tests are 

required. If the ASRI test EC50 is < 20 

mg/L, then choose either: (i) the 

Biodegradation in Activated Sludge 

(835.3280), or (ii) the Simulation Test – 

Aerobic Sewage Treatment: A. Activated 

Sludge Units (835.3240), or (iii) the 

Porous Pot Test (835.3220). If the ASRI 

835.3220 

or 

Porous Pot Study, 

TGAI or 

835.3240 

or 

Simulation Test – 

Aerobic Sewage 

Treatment: A 

Activated Sludge 

Units, TGAI or 

 
89 

Guideline Description MRID Classification Data 

Gap? Comments 

835.3280 

Simulation Tests 

to Assess the 

Primary and 

Ultimate 

Biodegradability 

of Chemicals 

Discharged to 

Wastewater, also 

referred to as the 

Biodegradation in 

Activated Sludge 

Test TGAI 

test EC50 is > 20 mg/L, then the applicant 

must choose either: (i) Ready 

Biodegradability (835.3110), or (ii) a) 

Biodegradation in Activated Sludge 

(835.3280), or b) the Simulation Test – 

Aerobic Sewage Treatment: A. Activated 

Sludge Units (835.3240), or c) the Porous 

Pot Test (835.3220). If the Ready 

Biodegradability study is conducted and 

the antimicrobial passes, then no further 

testing is required. If, however, the 

antimicrobial fails the Ready 

Biodegradability Study, then the (i) 

Biodegradation in Activated Sludge, or 

(ii) Simulation Test – Aerobic Sewage 

Treatment: A. Activated Sludge Units or 

(iii) the Porous Pot Study is required. In 

the absence of this data, no 

biodegradation of the test compound 

during wastewater treatment would be 

assumed. Required for the antimicrobial 

down-the-drain analysis.

835.4100 Aerobic Soil 

Metabolism 

00087351 

00040547 Supplemental

Yes 

Each of the submitted studies has 

deficiencies that limit the use of the data 

(see Table 5). In addition, chlorothalonil 

transformation in soil has been shown to 

be concentration dependent and none of 

the submitted studies have been 

conducted at the maximum use rates for 

agricultural or conventional nonagriculture uses. A new study that 

explores current maximum single 

application rates is required so that an 

appropriately representative half-life 

value can be calculated. Antimicrobial 

uses, will have much lower loading rates 

than the agricultural uses and 

conventional non-ag uses, and therefore 

this is not identified as a data gap for 

antimicrobial uses. 

43879601 Supplemental

47207702 Supplemental

47207703 Supplemental

835.4200 Anaerobic Soil 

Metabolism No data available Yes 

No data have been submitted to fulfill 

this data requirement; however, an 

anaerobic aquatic metabolism study is 

being requested in lieu of the anaerobic 

soil metabolism study. 

835.4300 Aerobic Aquatic 

Metabolism 

45908001 Supplemental Yes None of the studies identified all the 

42226101 Supplemental major transformation products and it is 
90 

Guideline Description MRID Classification Data 

Gap? Comments 

47207701 Supplemental

unclear if the degradation rates can be 

accurately calculated based on the 

submitted data. For these reasons, 

additional data are needed on the 

transformation rate of chlorothalonil in 

aerobic aquatic systems as well as full 

characterization of all major 

transformation products or transformation 

products of toxicological concern. 

835.4400 

Anaerobic 

Aquatic 

Metabolism 

00147975 Supplemental Yes 

Redox potentials and oxygen 

concentrations during the experiment 

were not provided; therefore, it cannot be 

confirmed that the system was anaerobic. 

No data are provided for day 0. The study 

was also terminated before the pattern of 

formation and decline could be 

established for the transformation 

products in one of the test systems. The 

test systems did not use an appropriate 

sediment/water matrix. A new anaerobic 

aquatic study is required. 

835.1230 

835.1240 

Adsorption/ 

Desorption 

Batch 

Equilibrium 

00029406 Supplemental Yes 

Information is needed on the desorption 

of chlorothalonil as well as the 

temperature and the light conditions used 

in this experiment, if this cannot be 

provided a new study is required. 

835.6100 Terrestrial Field 

Dissipation 

00071627, 00087369, 

00087332, 00087301 Supplemental

Yes 

There were several deficiencies in the 

submitted studies including: no storage 

stability data, inadequate sampling 

intervals, limited sampling depths. 

Additional information is needed to 

confirm the chlorothalonil dissipation 

conceptual model proposed based on the 

laboratory data. In addition, 

environmental chemistry methods for 

water and soil should be submitted for 

chlorothalonil. This study is not required 

to conduct the risk assessment for 

antimicrobial uses. 

00071625 Supplemental

835.8100 Field Volatility No data available Yes No data has been provided on the field 

volatility of chlorothalonil. 

835.6200 Aquatic Field 

Dissipation 127861 Acceptable No 

850.1730 Fish 

Bioconcentration 45710224 Acceptable No 

850.1710 Oyster 

Bioconcentration, 43070601 Acceptable No 
91 

Guideline Description MRID Classification Data 

Gap? Comments 

Special 

Study 

Wood Leaching 

Study, TEP No data ─ Yes 

To determine leach rate of chlorothalonil 

and its major toxic transformation 

products, and impurities of concern out of 

preserved wood for use in modeling 

loading to soil from rain washoff of 

antimicrobial applied wood preservatives. 

The leach rate from other material 

preservative uses (e.g., stucco, paint, 

coating, and caulk) is desired but in the 

absence of leaching data, the wood 

leaching results will be assumed to apply. 

A protocol should be submitted for 

Agency review prior to conducting the 

study. 

Data deficiencies: 

Data deficiencies and data gaps described in this assessment were identified in previous 

assessments (see 1999 RED, 2007 CRLF Assessment, and D371947) and are summarized below. 

Data on the amount of SDS-3701 expected after chlorothalonil application to only peanut hay, 

turf, and grass grown for seed are available and do not provide a dependable basis for estimating 

the amount of SDS-3701 that may form on avian and mammalian food items (i.e., tall and short 

grass). Also, most of the available residue studies were designed to measure the amount of SDS3701 that is taken up by crops and how much accumulates in vegetable items associated with 

human consumption such as beans and fruits, rather than pesticide concentrations on animal food 

items. The amount of SDS-3701 available for terrestrial animal consumption is an uncertainty.

Additionally, EFED recommends that the Agency work with the chlorothalonil registrants to 

establish the levels of the known chlorothalonil impurities (i.e., HCB and dioxin/furans) in 

currently registered products. EFED does not anticipate requiring any environmental effectsrelated data for HCB and dioxin/furans. 

H. EFFECTS

Data gaps: 

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

aquatic and terrestrial organisms, data gaps still exist to support both conventional and 

antimicrobial uses. Data gaps include the following: avian acute oral toxicity (passerine), avian 

acute inhalation, terrestrial plant, acute and chronic estuarine-marine fish, chronic estuarinemarine invertebrate, freshwater and estuarine/marine sediment toxicity, and activated sludge 

respiration inhibition. These data gaps are discussed below in Tables 18, 19, and 20. 
92 

Table 18. Summary of Ecological Effects Data for Terrestrial Animals Exposed to 

Chlorothalonil and Identified Data Gaps. 

Guideline Description MRID Classification Data 

Gap?* Comments 

850.2100 Avian acute oral 

toxicity 00068753 Acceptable Yes1

(C) 1

 Avian acute oral toxicity 

data are not available for 

passerines, which are 

required under the 40 

CFR Part 158. Therefore, 

this is identified as a data 

gap. 

2

 An evaluation of 

inhalation as a route of 

exposure using the 

Screening Tool for 

Inhalation Risk (STIR, v. 

1.0) model suggests that 

inhalation exposure is a 

pathway of concern for 

avian wildlife due to 

vapor-phase pesticide 

850.2200 Avian dietary 

toxicity 

00030388 Acceptable No 00039146 Acceptable 

Special 

study 

Avian acute 

inhalation 

No data 

available Not applicable Yes2(C) 

850.2300 Avian reproduction 45710218 Acceptable No 

850.3020 Honeybee acute 

contact toxicity 00077759 Acceptable No 

* C = data gap for conventional uses 

Table19. Summary of Ecological Effects Data for Aquatic Animals Exposed to 

Chlorothalonil and Identified Data Gaps 

Guideline Description MRID Classification Data 

Gap?* Comments 

850.1075 Freshwater fish – 

Acute toxicity 45710219 Acceptable No 1

Study re-classified due 

to variability in 

reproduction stemming 

from number of 

replicates and issues 

with solvent control 

survival. However, a 

new study is not 

requested at this time. 

2

 Classification based 

on instability of test 

material in test 

solutions however a 

new study is not 

requested at this time. 

3

Conducted as static test 

850.1500 Freshwater fish – 

Life-cycle toxicity 00030391 Supplemental1 No

850.1010

Freshwater 

invertebrates – 

Acute toxicity 

45710221 

(TGAI) Acceptable No 

850.1300 

Freshwater 

invertebrate – 

life cycle test 

45710222 

(TGAI) Supplemental2 No 

850.1075 Saltwater fish – 

Acute toxicity 00127863 Supplemental3 Yes 

(C,A) 
93 

Guideline Description MRID Classification Data 

Gap?* Comments 

850.1025 

(shell dep) 

Saltwater 

invertebrates – Acute 

toxicity 

00138143 

(TGAI; 

presumably 

parent 

compound) 

Acceptable No 

and did not measure test 

concentrations, study 

not for quantitative use 

4

The submission of 

study is needed. 

5

Study yielded nondefinitive endpoint. 

850.1400 Saltwater fish – 

early life stage test No data No data4 Yes 

(C,A) 

850.1350 

Saltwater 

invertebrates – life 

cycle test 

42433807 

(TGAI) Unacceptable5 Yes 

(C,A) 

850.1735 

Freshwater 

invertebrate – Acute 

whole sediment 

No Data No data4 Yes 

(C,A) 

850.1740 

Estuarine/marine 

invertebrate – Acute 

whole sediment 

No Data No data4 Yes 

(C,A) 

* C, A = data gap for both conventional and antimicrobial uses 

Table 20. Summary of Ecological Effects Data for Plants Exposed to Chlorothalonil and 

Identified Data Gaps 

Guideline Description MRID Classification Data 

Gap?* Comments 

850.4100 

Terrestrial Plant 

toxicity: seedling 

emergence 

(Tier 1) 

42433808 Acceptable Yes 

(C) 

The study was not conducted with a 

typical end-use product (TEP) – it 

was conducted using TGAI and a 

solvent (acetone). At 16 lbs 

a.i./acre (1.2 times the highest 

currently registered single 

application rate) there was a 26% 

inhibition in plant growth for onion 

when compared to the negative 

control. 

850.4150 

Terrestrial Plant 

toxicity: vegetative 

vigor 

(Tier 1) 

42433809 Acceptable Yes 

(C) 

The study was not conducted with a 

typical end-use product (TEP) – it 

was conducted using TGAI and a 

solvent (acetone). At 16 lb a.i./acre 

(1.2 times the highest currently 

registered single application rate) 

there was a 26% inhibition in plant 

growth for cucumber when 

compared to the negative control. 

850.5400 

Aquatic Plant 

Growth: algae 

(Tier 1 & 2) 

44908105 Acceptable 

No -- 44908103 Acceptable 

42432801 Acceptable 
94 

Guideline Description MRID Classification Data 

Gap?* Comments 

44908104 Acceptable 

850.4400 

Aquatic Plant 

Growth: vascular 

plants 

(Tier 1 & 2) 

44908102 Acceptable No -- 

850.6800 

or OECD 

209

Activated Sludge 

Respiration 

Inhibition

No data ─ Yes 

(A) -- 

* C = data gap for conventional uses 

 A = data gap for antimicrobial uses 

 C,A = data gap for both conventional and antimicrobial uses 

Avian Acute Oral Toxicity 

Acceptable acute avian oral toxicity data were submitted for exposures of mallard duck to 

chlorothalonil; however, data are not available for passerines, which are required under the 40 

CFR Part 158 (Oct. 26, 2007) data requirements for conventional pesticides (72 FR 60934; 

USEPA 2007d). The Part 158 data requirements specify that acute avian oral toxicity data be 

submitted for either a mallard duck or bobwhite quail and a passerine species. Therefore, an 

avian oral toxicity test (OCSPP Guideline 850.2100) is needed for passerine birds, as specified in 

40 CFR Part 158 (Oct. 26, 2007). 

Although, there were no mortalities observed during the acute oral study available for mallard 

ducks and the LD50 value was determined to be greater than 4,640 mg/kg-bw (the highest 

concentration tested), the LOAEC in this study was determined to be 2,150 mg a.i./kg-bw based 

on reduced body weight. Weight loss was also noted in the available avian sub-acute dietary 

studies, indicating potential toxicity of chlorothalonil to birds. Therefore, this indicates that 

chlorothalonil may be toxic to birds. 

EFED recommends that the Pesticide Re-evaluation Division (PRD) request submission of a 

passerine study protocol for review by the Agency prior to initiation of this study. If oral acute 

toxicity data are not submitted for passerines, EFED will assume acute risk for passerine species. 
95 

Avian Acute Inhalation Toxicity 

Acceptable acute avian toxicity data were submitted for oral exposures of mallard duck (Anas 

platyrhynchos) to chlorothalonil; however, data are not available for inhalation toxicity. Acute 

toxicity data using rats indicate that mammals are much more sensitive to chlorothalonil when 

exposed via the inhalation route compared to the oral route. Furthermore, an evaluation of 

inhalation as a route of exposure using the Screening Tool for Inhalation Risk (STIR, v. 1.0) 

model suggests that inhalation exposure is a pathway of concern for avian wildlife due to vaporphase pesticide. Therefore, EFED recommends requesting an acute avian inhalation toxicity test 

using the most sensitive avian species as shown by avian acute oral studies. The study being 

requested will aid in evaluating this pathway of concern for avian taxa. An avian inhalation study 

protocol must be submitted for review and approval by the Agency prior to initiation of this 

study. 

Terrestrial Plant Studies 

Terrestrial plant toxicity studies using TEP(s) and associated risk analysis of plants are required 

for registration of conventional pesticides with outdoor uses (CFR Part 158). For terrestrial 

plants, Tier II studies are required when potential concerns are triggered (i.e., when there is some 

indication that there may be significant toxicity to plants). These indicators may be an herbicidal 

mode of action, statements on the label indicating toxicity to plants, or ≥ 25% effect levels in the 

Tier I studies. 

Tier I seedling emergence and vegetative vigor studies are available for chlorothalonil using 16 

lb a.i./acre test concentrations (MRIDs 42433808 and 42433809). These studies were not 

conducted with a typical end-use product (TEP), but were instead conducted using chlorothalonil 

mixed with a solvent (100% acetone). When the results are compared to the negative (and not 

the pooled) control, onion shows an inhibition in growth of 26% in the seedling emergence study 

and cucumber shows a 26% inhibition in growth in the vegetative vigor study at the 16 lbs 

a.i./acre concentration. 

Because these studies were conducted using TGAI mixed with acetone (instead of a TEP) and 

there were effects greater than 25% noted in the studies for some species, EFED recommends 

that these data be requested for the chlorothalonil risk assessment. If additional toxicity data for 

terrestrial plants are not submitted for chlorothalonil, EFED will assume risk for terrestrial 

plants. 

Acute and Chronic Estuarine-marine Fish Studies 

The available acute sheepshead study was conducted as a static study and the test concentrations 

were not measured. Given the difficulties in maintaining test concentrations observed in other 

aquatic fish toxicity studies, there is substantial uncertainty in the actual exposure concentrations 

in the acute sheepshead study. As chlorothalonil is very highly toxic to fish, the use of nominal 

test concentrations is probably underestimating risk to estuarine-marine fish. 
96 

A chronic toxicity test with chlorothalonil for estuarine-marine fish is not available. As 

chlorothalonil is toxic to fish, this study is needed to evaluate risk to estuarine-marine fish. If 

data are not provided, EFED will assume risk to estuarine-marine fish. 

Chronic Estuarine-marine Invertebrate Study 

The available chronic mysid shrimp toxicity study is classified as unacceptable based on several 

factors: 1) test concentrations of several replicates were variable and did not meet ASTM 

requirements; 2) average solvent control survival was only 62%; and, 3) the NOAEC and MATC 

could not be determined. A recalculation (Dunnett’s test) of the endpoints for this study using the 

current methodology of using the negative control yielded a significant difference at every 

concentration level and a non-definitive NOAEC of <0.65 μg a.i./L. On this basis and additional 

issues with the study, this study has been re-classified as unacceptable and a new study is 

requested at this time. 

Freshwater and Estuarine-marine Sediment Studies 

Based on it use pattern and fate properties, chlorothalonil has the potential to reach freshwater 

and estuarine-marine aquatic environments and bind to sediment. In addition, a 28-day study, in 

which chlorothalonil was applied to water, provided evidence that chlorothalonil is toxic to 

sediment-dwelling organisms in a water-sediment system. Therefore, 10-day toxicity test 

following OPPTS 850.1735 and 850.1740 guidelines are requested for both freshwater 

organisms, Chironomus tentans and Hyallela azteca as well as the recommended 

estuarine/marine organism, Leptocheirus plumulosus. However, since chlorothalonil may be 

persistent in terrestrial environments, based on the aerobic soil metabolism, and is expected to 

enter aquatic environments through runoff, this runoff may provide a more chronic or pulsed 

exposure to sediment organisms. Therefore, it is recommended that after the 10-day studies are 

submitted and reviewed, if there is evidence that chronic toxicity testing may be warranted 

(based on observed toxicity and persistence in the 10-day studies and modeled EECs), then 

chronic testing, which would evaluate reproduction as well as survival and growth, should also 

be requested. 

I. OTHER INFORMATION NEEDS

There is specific information that will assist the Agency in refining the environmental fate, 

ecological risk, endangered species, and drinking water exposure assessments, including any 

species-specific effects determinations. The Agency is very much interested in obtaining the 

following information: 

1. confirmation on the following label information 

a. frequency of application, application intervals, and maximum number of 

applications per season 

b. geographic limitations on use 

2. use or potential use distribution (e.g., acreage and geographical distribution of relevant 

crops) 

3. use history 
97 

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. usage/use information for non-agricultural uses (e.g., forestry, residential, rights-of-way) 

8. 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 

9. typical interval (days) 

10. state or local use restrictions 

11. ecological incidents (non-target plant damage and avian, fish, reptilian, amphibian and 

mammalian mortalities) not already reported to the Agency 

12. monitoring data 

13. the amount of dioxins/furans, and HCB present in technical chlorothalonil. 

The analysis plan will be revisited and may be revised depending upon the data available in the 

open literature and the information submitted by the public in response to the opening of the 

Registration review docket. 
98 

APPENDIX A. REFERENCES 

Agency for Toxic Substances and Disease Registry (ATSDR). 2002. Toxicological Profile for 

 Hexachlorobenzene. U.S. Department of Health and Human Services. Public Health 

 Service. 

Ernst, W.R; J.D.A. Vaughn; A.L. Huybers; K.G. Doe; P.A. Hennigar PA. 1993. The toxicity of 

chlorothalonil and its 4-hydroxy metabolite to selected aquatic species. Environment 

Canada, Environmental Protection, Conservation and Protection, Dartmouth, Nova 

Scotia. Unpublished manuscript 

Hahn, ME. 2002. Aryl hydrocarbon receptors: diversity and evolution. Chem Biol Interact 

141:131-160. 

Isensee, A.R. and G.E. Jones. 1975. Distribution of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) 

 in aquatic model ecosystem. Environ. Sci. Technol. 9:668-672. 

Isensee, A.R. 1978. Bioaccumulation of 2,3,7,8-tetrachlorodibenzo-para-dioxin. Ecol. Bull. 

 (Stockholm) 27:255-262. 

Killeen JC Jr.; G.A. Leblanc; G.A. Cary. 1977. Acute Toxicity of DS-3701 to the water flea 

(Daphnia magna). EG & G Bionomics report to Diamond and Shamrock Corporation 

Report No. 1000-5TX-77-0071-001. 

McMahon, T.; N. Halstead; S. Johnson; T. Raffel, J. M. Romansic; P. W. Crumrine; R.K. 

Boughton; L. B. Martin; J. R. Rohr. 2011. The Fungicide Chlorothalonil is Nonlinearly 

Associated with Corticosterone Levels, Immunity, and Mortality in Amphibians. 

Environ. Health Perspect. 119:1098-1103. http://dx.doi.org/10.1289/ehp.1002956

Mezcua, M.; M.D. Hernando; L. Piedra; A. Aguera; A.R. Fernandez-Alba. 2002. 

Chromatogrophy-Mass Spectrometry and Toxicity Evaluation of Selected Contaminants 

in Seawater. Chromatographia 56(3/4):199-205 

Murray, F.J., Smith, F.A., Nitschke, K.D., Huniston, C.G, Kociba, R.J, and B.A. Schwetz. 1979. 

 Three-generation reproduction study of rats given 2,3,7,8-tetrachlorodobenzo-p- diozin 

 (TCDD) in the diet. Toxicol. Appl. Pharmacol. 50:241-252. 

Nosek, J.A., Sullivan, J.R., Hurley, S.S., Olson, J.R., Craven, S.R. and R.E. Peterson. 1992a. 

 Metabolism and disposition of 2,3,7,8-tetrachlorodibenzo-p-dioxin in ring-necked 

 pheasant hens, chicks, and eggs.. J. Toxicol. Environ. Health, 35:153-164. 

Nosek, J.A., Sullivan, J.R., Hurley, S.S., Craven, S.R. and R.E. Peterson. 1992b. Toxicity and 

 reproductive effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin toxicity in ring-necked 

 pheasant hens. J. Toxicol. Environ. Health, 35: 187-198. 
99 

Nosek, J.A., Sullivan, Amundson, T.E., Craven, S.R., Miller, L.M., Fitzpatrick, A.G., Cook, 

 M.E. and R.E. Peterson. 1993. Embryotoxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in 

 the ring-necked pheasants. Environ. Toxicol. Chem. 12:1215-1222. 

U.S. EPA. 1995. Great Lakes Water Quality Initiative criteria Documents for the Protection of 

 Wildlife – DDT, Mercury, 2,3,7,8-TCDD, PCBs. U.S. Environmental Protection 

 Agency, Office of Water. March 1995. EPA/820/B/95/008. 

U.S. EPA. 2003a. Exposure and Human Health Reassessment of 2,3,7,8-Tetrachlorodibenzo-pdioxin (TCDD) and Related Compounds. Part 1. Estimating Exposure to Dioxin-Like 

Compounds. Volume 2. Properties, Environmental Levels, and Background Exposures. 

NAS Review Draft. December 2003. EPA/600/P-00/001Cb. National Center for 

Environmental Assessment. Office of Research and Development. Washington, D.C. 

Available at: http://www.epa.gov/ncea/pdfs/dioxin/nas-review/ (accessed 02/04/2009) 

U.S. EPA. 2003b. analysis of laboratory and field studies of reproductive toxicity in birds 

 exposed to dioxin-like compounds for use in ecological risk assessment. United States 

 Environmental Protection Agency. Office of Research and Development. National Center 

 for Environmental Assessment. Cincinnati, OH. EPA/600/R-03/114F. April, 2003. 

U.S. EPA. 2004. Overview of the Ecological Risk Assessment Process in the Office of Pesticide 

Programs. January 23, 2004. Office of Pesticide Programs. Office of Prevention, 

Pesticides, and Toxic Substances. Washington, D.C. Available at: 

http://www.epa.gov/espp/consultation/ecorisk-overview.pdf (accessed January 26, 2009) 

U.S. EPA, 2006b. Technical Factsheet on: Dioxin (2,3,7,8-TCDD). National Primary Drinking 

Water Regulations. Office of Water. Washington, D.C. Available at: 

http://www.epa.gov/OGWDW/dwh/t-soc/dioxin.html (accessed February 4, 2009) 

U.S. EPA. 2008b. Framework for application of the toxicity equivalence methodology for 

 polychlorinated dioxins, furans, and biphenyls in ecological risk assessment. United 

 States Environmental Protection Agency. Office of the Science Advisor, Risk 

 Assessment Forum. EPA 100/R-08/004. June 2008. 

Van den Berg, M., L. Birnbaum, A.T. Bosveld et al. 1998. Toxic equivalency factors (TEFs) for 

 PCBs, PCDDs, PCDFs for humans and wildlife. Environ. Health Perspect. 106(12):775-

 792. 

Van den Berg, M., L.S. Birnbaum, M. Denison et al. 2006. The 2005 World Health Organization 

 re-evaluation of human and mammalian toxic equivalency factors for dioxins and dioxin-

 like compounds. Toxicol. Sci. 93(2):223-241. 
100 

APPENDIX B: SUBMITTED ENVIRONMENTAL FATE AND ECOLOGICAL 

STUDIES FOR THE REGISTRATION OF CHLOROTHALONIL 

161-1 Hydrolysis 

MRID Citation Reference 

0040539 

161-2 Photodegradation-water 

MRID Citation Reference 

40183418 Nelsen, T. (1987) An Aqueous Photolysis Study with [Carbon 14]- 2,4,5,6-

Tetrachloroisophthalonitrile (Chlorothalonil), SDS- 2787: Ricerca Study No. 85-0075. 

Unpublished study prepared by Ricerca, Inc. 59 p. 

41030001 Doran, T. (1989) An Aqueous Photolysis Study with ^Carbon 14|-2,4, 5,6-

Tetrachloroisothalonitrile (Chlorothalonil), SDS-2787: Document No. 1185-85-0075-EF-001. 

Unpublished study prepared by Ricerca, Inc. 35 p. 

45710223 Kirkpatrick, D. (1996) Chlorothalonil Photodegradation in Water: Lab Project Number: VCM 

42/951419: VCM/42. Unpublished study prepared by Huntingdon Research Centre Ltd. 78 p. 

40540 Szalkowski, M.B. (1976) Photodegradation of Daconil in Aqueous Systems. (Unpublished study 

received Feb 25, 1976 under 6F1749; submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:096466-C) 

87281 Wolfe, A.L. (1972) The Effect of Ultraviolet Radiation on 4- Hydroxy-2,5,6-

trichloroisophthalonitrile in Aqueous Solutions. (Unpublished study received Aug 11, 1970 

under 1F1024; submitted by Diamond Shamrock Chemical Co., Cleveland, Ohio; CDL:093333-

A) 

161-3 Photodegradation-soil 

MRID Citation Reference 

40541 Szalkowski, M.B. (1976) Photodegradation of Daconil and Its Metab- olite, 4-Hydroxy-2,5,6-

trichloroisophthalonitrile, on Inert Surfaces. (Unpublished study received Feb 25, 1976 under 

6F1749; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; 

CDL:096466-D) 

40542 Szalkowski, M.B. (1975) Photodegradation of Daconil and 4-Hydroxy- 2,5,6-

trichloroisophthalonitrile on Silica Gel Plates. (Unpub- lished study received Feb 25, 1976 under 

6F1749; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL: 

096466-E) 

40543 Szalkowski, M.B. (19??) Photodegradation and Mobility of Daconil and Its Major Metabolite on 

Soil Thin Films. (Unpublished study received Feb 25, 1976 under 6F1749; submitted by 

Diamond Sham- rock Agricultural Chemicals, Cleveland, Ohio; CDL:096466-F) 

87348 Szalkowski, M.B. (1975) Photodegradation of Daconil and 4-Hydroxy- 2,5,6-

trichloroisophthalonitrile on Silica Gel Plates. (Unpub- lished study received Feb 25, 1976 under 

6F1749; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL: 

097394-D) 
101 

87349 Szalkowski, M.B. (1975) Photodegradation and Mobility of Daconil and Its Major Metabolite on 

Soil Thin Films. (Unpublished study received Feb 25, 1976 under 6F1749; submitted by 

Diamond Sham- rock Agricultural Chemicals, Cleveland, Ohio; CDL:097394-E) 

143751 Szalkowski, M. (19??) Photodegradation and Mobility of Daconil and Its Major Metabolite on 

Soil Thin Films. Unpublished study prepared by Diamond Shamrock Corp. 35 p. 

UNACCEPTABLE:

156470 Nelson, T. (1985) Scientific Validity of the [Carbon-14] Chlorothalonil Soil Photolysis Study. 

Unpublished study prepared by SDS Biotech Corp. 27 p. 

41030002 Nelsen, T. (1989) Photodegradation and Mobility of Daconil and Its Major Metabolite on Soil 

Thin Films. Unpublished study prepared by Fermenta Plant Protection Co. 22 p. 

162-1 Aerobic soil metabolism 

MRID Citation Reference 

40547 Szalkowski, M.B. (1976) Effect of Microorganisms upon the Soil Metabolism of Daconil and 4-

Hydroxy-2,5,6,trichloroisophthalo- nitrile. (Unpublished study received Feb 25, 1976 under 

6F1749; prepared in cooperation with Ohio State Univ., Soil Testing Laboratory, submitted by 

Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:096466-J) 

87285 Duane, W.C. (1970) Biodegradation of Daconil 2787. (Unpublished study received Aug 11, 

1970 under 1F1024; submitted by Diamond Shamrock Chemical Co., Cleveland, Ohio; 

CDL:093333-E). 

87351 Szalkowski, M.B. (1976) Effect of Microorganisms upon the Soil Metabolism of Daconil and 4-

Hydroxy-2,5,6-trichloroisophthalo- nitrile. (Unpublished study received Feb 25, 1976 under 

6F1749; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; 

CDL:097394-I) 

114035 Diamond Shamrock Chemical Co. (1970) The Results of Tests on the Amount of Residue 

Remaining, Including a Description of the Analytical Method Used: ?Daconil 2787|. 

(Compilation; unpub- lished study received Sep 1, 1971 under 1F1024; CDL:091899-B) 

43879601 Duane, W. (1995) Aerobic Metabolism of (carbon 14)-Chlorothalonil in Soil: Lab Project 

Number: 93-0295: SDS-2787: 5905-93-0295-EF-002. Unpublished study prepared by Ricerca, 

Inc. 105 p. 

47207702 Gibbings, E.; Bramley, Y. (2000) Chlorothalonil: Aerobic Soil Degradation at Four Treatment 

Rates: Final Report. Project Number: TMJ4487B, T003973/07. Unpublished study prepared by 

Syngenta Jealotts Hill International. 37 p. 

47207703 Bramley, Y.; Gibbings, E. (2001) Chlorothalonil: Degradation in Aerobic Soil: Final Report. 

Project Number: RJ3099B, T003974/07. Unpublished study prepared by Syngenta Jealotts Hill 

International. 68 p. 

162-2 Anaerobic soil metabolism 

MRID Citation Reference 

162-3 Anaerobic aquatic metab. 

MRID Citation Reference 

45330901 Gentle, W. (1999) Chlorothalonil: Dissipation in a 30cm Deep Indoor Aquatic Microcosm: Lab 

Project Number: TMJ4216B. Unpublished study prepared by Zeneca Agrochemicals. 15 p. 
102 

147975 Nelsen, T. (1985) An Anaerobic Aquatic Soil Metabolism Study with [Radiolabeled Carbon]-

chlorothalonil: Document No. 680-3EF-84- 0026-001. Unpublished study prepared by SDS 

Biotech Corp. 68 p. 

162-4 Aerobic aquatic metab. 

MRID Citation Reference 

42226101 Hatzenbeler, C. (1991) An Aerobic Aquatic Soil Metabolism Study with ?carbon 14|-

Chlorothalonil: Lab Project Number: 90-0240; 3163-90-0240-EF-001. Unpublished study 

prepared by Ricerca, Inc. 137 p. 

43890604 Frazier, H. (1995) Chlorothalonil--A Summary of Aerobic Aquatic Degradation Data (Half-Life 

Values) in Natural Water: Lab Project Number: 5980-95-0263-EF-001: 95-0263: J9203008. 

Unpublished study prepared by Ricerca, Inc. and Toxikon Environmental Sciences. 65 p. 

47207701 Hurt, A.; Oliver, S. (2002) Chlorothalonil: Degradation of (Carbon 14)-Labelled Compound in 

Natural Water Sediment Systems Under Laboratory Conditions: Final Report. Project Number: 

RJ3227B, T003976/07. Unpublished study prepared by Syngenta Jealotts Hill International. 86 

p. 

163-1 Leach/adsorp/desorption 

MRID Citation Reference 

29406 Szalkowski, M.B.; Stallard, D.E. (1980) Adsorption of Chloro- thalonil (2,4,5,6-

Tetrachloroisophthalonitrile) DS-2787. (Un- published study received Feb 19, 1980 under 677-

313; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:099248-

D) 

29407 Szalkowski, M.B.; Mannion, J.J.; Stallard, D.E.; et al. (1979) Quantitation and Characterization 

of the Biotransformation Pro- ducts of 2,4,5,6-Tetrachloroisophthalonitrile (Chlorothalonil, DS2787) in Soil. (Unpublished study received Feb 19, 1980 un- der 677-313; submitted by 

Diamond Shamrock Agricultural Chemi- cals, Cleveland, Ohio; CDL:099248-E) 

40546 Szalkowski, M.B. (1976) Leaching of Degradation Products. (Unpub- lished study received on 

unknown date under 6F1749; submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:096466-I) 

71058 Johnston, E.F. (1981) Soil Disappearance Studies with Benlate^(R)I Fungicide and Bravo^(R)I 

500 F Fungicide, Alone and in Combina- tion: Document No. AMR-06-81. (Unpublished study 

received Feb 27, 1981 under 352-354; submitted by E.I. du Pont de Nemours & Co., 

Wilmington, Del.; CDL:244633-B) 

87286 Wolfe, A.L.; Stallard, D.E. (1968) The Fate of DAC-3701 (4-Hydroxy- 2,5,6-

trichloroisophthalonitrile) in Soil. (Unpublished study received Aug 11, 1970 under 1F1024; 

submitted by Diamond Sham- rock Chemical Co., Cleveland, Ohio; CDL:093333-F) 

87332 Stallard, D.E.; Wolfe, A.L. (1967) The Fate of 2,4,5,6-Tetra- chloroisophthalonitrile (Daconil 

2787) in Soil. (Unpublished study received May 17, 1967 under 7F0599; submitted by Diamond 

Alkali Co., Cleveland, Ohio; CDL:090770-J) 

87349 Szalkowski, M.B. (1975) Photodegradation and Mobility of Daconil and Its Major Metabolite on 

Soil Thin Films. (Unpublished study received Feb 25, 1976 under 6F1749; submitted by 

Diamond Sham- rock Agricultural Chemicals, Cleveland, Ohio; CDL:097394-E) 

87350 Szalkowski, M.B. (1976) Leaching of Degradation Products: ?Daco- nil|. (Unpublished study 

received Feb 25, 1976 under 6F1749; submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:097394-H) 
103 

87369 Skinner, W.A.; Wolfe, A.L.; Stallard, D.E. (1965) Determinations of the Fate of 2,4,5,6-

Tetrachloroisophthalonitrile (Daconil 2787) in Soil. (Unpublished study received Sep 30, 1965 

under 677- 229; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; 

CDL:120430-A) 

115105 Capps, T.; Marciniszyn, J.; Marks, A.; et al. (1982) Adsorption and Desorption of Chlorothalonil 

to Soils: Document No. 555-4EF-81- 0216-001. (Unpublished study received Sep 21, 1982 

under 0F2405; submitted by Diamond Shamrock Corp., Cleveland, OH; CDL: 071096-B) 

137232 Nelsen, T.; Marks, A.; Ignatoski, J. (1983) Mobility of Chlorothal- onil and Metabolites in Soil: 

Document No. 000-3EF-83-0112-002; Report/DS-2787. (Unpublished study received Dec 20, 

1983 under 50534-8; submitted by SDS Biotech Corp., Painesville, OH; CDL: 252253-A) 

138144 Vonk, J.; Van Den Hoven, A.; De Jong, P.; et al. (1983) Mobility of Chlorothalonil and 

Metabolites in Soil: Report No. 83/0684a/ 4205-61044/HV/IH. (Unpublished study received Jan 

10, 1984 under 50534-8; prepared by Institute of Applied Chemistry TNO, Neth., submitted by 

SDS Biotech Corp., Painesville, OH; CDL: 072267-A) 

143752 Nelson, T. (1985) An Aged Soil Leaching Study with [Carbon-14]- Chlorothalonil (2, 4, 5, 6-

Tetrachloroisophthalonitrile). Un- published study prepared by SDS Biotech Corporation. 13 p. 

153730 Nelson, T. (1985) An Aged Soil Leaching Study with [Carbon-14]- Chlorothalonil (2, 4, 5, 6-

Tetrachloroisophthalonitrile): Report No. SDS-2787. Unpublished study prepared by SDS 

Biotech Corp. 71 p. 

153731 Capps, T. (1982) Adsorption and Desorption of Chlorothalonil to Soils: Report No. DS-2787. 

Unpublished study prepared by Dia- mond Shamrock Corp. 57 p. 

44483404 Waller, R. (1992) Adsorption and Desorption of SDS-46851 to Soils: Lab Project Number: 90-

0374: 3605-90-0374-EF-001: REPORT/SDS-46851. Unpublished study prepared by Ricerca, 

Inc. 102 p. 

44483405 Archer, G. (1991) Adsorption and Desorption of SDS-3701 to Soils: Lab Project Number: 90-

0375: 3606-90-0375-EF-001: REPORT/SDS-3701. Unpublished study prepared by Ricerca, Inc. 

120 p. 

163-2 Volatility - lab 

MRID Citation Reference 

143751 Szalkowski, M. (19??) Photodegradation and Mobility of Daconil and Its Major Metabolite on 

Soil Thin Films. Unpublished study prepared by Diamond Shamrock Corp. 35 p. 

164-1 Terrestrial field dissipation 

MRID Citation Reference 

71625 Nixon, W.B. (1981) Tank Mix Soil Dissipation Studies: Ridomil^(R)I/ Bravo^(R)I; 

Ridomil^(R)I/Difolatan^(R)I; Ridomil^(R)I/Dithane M- 45^(R)I: Report No. EIR-81003. 

(Unpublished study received Apr 15, 1981 under 100-607; submitted by Ciba-Geigy Corp., 

Greens- boro, N.C.; CDL:070010-A) 

71627 Ciba-Geigy Corporation (1980) ?Tank Mix Soil Dissipation Studies with Various Chemicals|: 

AG-A 4801 I, II A. (Compilation; unpublished study, including AG-A 4801 I, II, III, 2nd Report 

A, 4802 I, II, III, 4802 I, II, III, Second Report B..., received Apr 15, 1981 under 100-607; 

CDL:070010-E) 

87296 Stallard, D.E.; Wolfe, A.L.; Duane, W.C. (1972) Evaluation of the Leaching of Chlorothalonil 

under Field Conditions and Its Poten- tial To Contaminate Underground Water Supplies. 

(Unpublished study received Feb 25, 1976 under 6F1749; submitted by Diamond Shamrock 
104 

Chemical Co., Cleveland, Ohio; CDL:098072-R) 

87300 Wolfe, A.L.; Stallard, D.E. (1965) Residue of Tetrachloroisoph- thalonitrile (Forturf) in Soil 

Resulting from Foliar Application to Established Turf. (Unpublished study received Dec 21, 

1965 under unknown admin. no.; submitted by Diamond Shamrock Chemical Co., Cleveland, 

Ohio; CDL:110552-A) 

87332 Stallard, D.E.; Wolfe, A.L. (1967) The Fate of 2,4,5,6-Tetra- chloroisophthalonitrile (Daconil 

2787) in Soil. (Unpublished study received May 17, 1967 under 7F0599; submitted by Diamond 

Alkali Co., Cleveland, Ohio; CDL:090770-J) 

87369 Skinner, W.A.; Wolfe, A.L.; Stallard, D.E. (1965) Determinations of the Fate of 2,4,5,6-

Tetrachloroisophthalonitrile (Daconil 2787) in Soil. (Unpublished study received Sep 30, 1965 

under 677- 229; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; 

CDL:120430-A) 

41564828 Rose, C.; Ballee, D. (1988) Determination of Residues (Field-Soil Dissipation) of 

Tetrachloroisophthalonitrile (Chlorothalonil, SDS-2787), Its Soil Metabolites and 

Manufacturing Impurities in Soil from Bravo Treated Areas-Donalsonville, GA-1986-1988: Lab 

Project Number: 1401-86-0084-CR-002: 1401-86-0084. Unpublished study prepared by Ricerca, 

Inc. 413 p. 

41564829 Formanik, J. (1989) Field-Soil Dissipation of Residues of Tetra- chloroisophthalonitrile 

(Chlorothalonil, SDS-2787), Its Soil Metabolites and Manufacturing Impurities in Soil from 

Bravo Treated Areas-Fresno, CA-1986-1988: Lab Project Number: 1401-86- 0084-cr-003: 

1401-86-0084. Unpublished study prepared by Ri- cerca, Inc. 550 p. 

41564830 King, C. (1989) Field-Soil Dissioation of Residues of Tetrachloro- isophthalonitrile 

(Chlorothalonil, SDS-2787), Its Degradation Products and Manufacturing Impurities in Soil 

from Bravo Treated Areas-Greenfirld, CA.-1986-1988: Lab Project Number: 1401-86- 0084-

CR-004. Unpublished study prepared by Ricerca, Inc. 361 p. 

42433813 Kenyon, R.; Ballee, D. (1991) Field Soil Dissipation of Residues of Tetrachloroisophthalonitrile 

(Chlorothalonil, SDS-2787), It's Soil Metabolites and Manufacturing Impurities in Soil from 

Bravo Treated Areas--Phelps, NY: 1986-1988: Lab Project Number: 86-0084: 1401-86-0084-

CR-018. Unpublished study prepared by ISK Biotech Corp. 340 p. 

42433814 Kenyon, R. (1991) Residues of Tetrachloroisophthalonitrile (Chlorothalonil, SDS-2787), It's 

Degradation Products and Manufacturing Impurities in Soil from a Stability Study--One Year 

Interim Report: Lab Project Number: 3436-89-0375: 3436-89-0375-CR-001. Unpublished study 

prepared by Ricerca, Inc. 137 p. 

42875907 Jacobson, B.; Schollenberger, J. (1992) Dissipation of 4-Hydroxy-2,4,5-

Trichloroisophthalonitrile (SDS-3701) in Soil: A Re-analysis of Chlorothalonil Soil Dissipation 

Data: Lab Project Number: 1874-T. Unpublished study prepared by Ricerca, Inc. 23 p. 

44006001 Ricerca, Inc. (1996) Environmental Fate of Chlorothalonil and Metabolites in Soil, Plants, 

Surface Water and Ground Water--Additional New Information: Lab Project Number: EF-96-

HF-020-001-001: WR 1201T: 762-3AS-86-0010-000. Unpublished study. 206 p. 

164-2 Aquatic field dissipation 

MRID Citation Reference 

127861 Diamond Shamrock Agricultural Chemicals (1982) ?Bravo: Residues in Rice and Other 

Subjects|. (Compilation; unpublished study re- ceived Apr 21, 1983 under 677-313; 

CDL:071553-B) 

45908001 Kirkpatrick, D. (1996) Chlorothalonil Degradability and Fate in Water/Sediment Systems: Lab 

Project Number: VCM 45: VCM 45/962245. Unpublished study prepared by Technology 
105 

Sciences Group Inc. 126 p. 

165-0 Accumulation Studies -- General 

MRID Citation Reference 

115104 Marciniszyn, J.; Marks, A.; Ignatoski, J. (1982) Characterization and Quantitation of 14Cresidues in Water, Soil and Fish Exposed to 14C-2,4,5,6-tetrachloroisophthalonitrile 

(Chlorothalonil, DS-2787) in a Static Aquatic System: Document No. 078-3EI-79- 0030-002. 

(Unpublished study received Sep 21, 1982 under 0F2405; submitted by Diamond Shamrock 

Corp., Cleveland, OH; CDL: 071096-A) 

127860 Stallard, D.; Marks, A.; Ignatoski, J.; et al. (1982) Evaluation of the Residues of ... 

Chlorothalonil, DS-2787 and ... DS-3701 on Rice Straw, Rice Grain and the Impact of Rice 

Paddy Ecology: Document No. 069-3CR-82-0136-001. (Unpublished study received Apr 21, 

1983 under 677-313; submitted by Diamond Shamrock Ag- ricultural Chemicals, Cleveland, 

OH; CDL:071553-A) 

127862 Hutchinson, C.; Shults, S.; Killeen, J.; et al. (1982) Aquatic Field Study with Bravo 500: 

Document No. 518-5TX-81-0171-003. (Unpublished study received Apr 21, 1983 under 677-

313; sub- mitted by Diamond Shamrock Agricultural Chemicals, Cleveland, OH; CDL:071552-

A) 

137146 Shults, S.; Killeen, J.; Ignatoski, J. (1982) Aquatic Field Study with Bravo 500: Document No. 

518-5TX-81-0171-003. (Unpublished study received Jan 18, 1984 under 50534-8; prepared by 

Diamond Shamrock Corp., submitted by SDS Biotech Corp., Painesville, OH; CDL:072280-A) 
106 

71-1 Avian Single Dose Oral Toxicity 

MRID Citation Reference 

30395 Beavers, J.B.; Fink, R.; Brown, R. (1978) Final Report: Acute Oral LD50--Mallard Duck: 

Project No. 111-110. (Unpublished study including submitter summary, received Feb 19, 1980 

under 677- 313; prepared by Wildlife International, Ltd. in cooperation with Washington 

College, submitted by Diamond Shamrock Agricul- tural Chemicals, Cleveland, Ohio; 

CDL:099247-N) 

68753 Fink, R.; Beavers, J.B.; Brown, R. (1977) Final Report: Acute Oral LD50--Mallard Duck: 

Project No. 111-109. (Unpublished study, including submitter summary, received Jan 19, 1978 

under 677- 229; prepared by Wildlife International Ltd. and Washington College, submitted by 

Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:232729-A) 

40964105 Shults, S.; Wilson, N.; Killeen, J. (1987) Acute Oral Toxicity (LD50) Study in Japanese Quail 

with Technical Chlorothalonil: Ricerca--Document No. 1582-87-0041-TX-002. Unpublished 

study prepared by Wildlife International Ltd. 54 p. 

71-2 Avian Dietary Toxicity 

MRID Citation Reference 

30388 Shults, S.K.; Killeen, J.C., Jr.; Heilman, R.D. (1979) Chlorothalo- nil (Technical) Eight-Day 

Dietary (LCI50^) Study in Bobwhite Quail. (Unpublished study received Feb 19, 1980 under 

677- 313; prepared in cooperation with Wildlife International, Ltd., submitted by Diamond 

Shamrock Agricultural Chemicals, Cleveland Ohio; CDL:099247-A) 

30389 Shults, S.K.; Killeen, J.C., Jr.; Heilman, R.D. (1979) Chlorothalonil (Technical) Eight-Day 

Dietary (LC50) Study in Mallard Ducks. (Unpublished study received Feb 19, 1980 under 677- 

313; prepared in cooperation with Wildlife International, Ltd., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, Ohio; CDL:099247-B) 

39146 Dieterich, W.H. (1965) Acute Dietary Administration--Wildfowl: Project No. 200-163. 

(Unpublished study received Feb 25, 1976 under 6F1749; prepared by Hazleton Laboratories, 

Inc., submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:096459-

B) 

115108 Shults, S.; Killeen, J.; Ignatoski, J. (1981) Dietary Study (LC50) in Mallard Ducks with DS3701 (4-Hydroxy-2,5,6-trichloroiso- phthalonitrile): Document No. 449-5TX-81-0008-002. 

(Unpublished study received Sep 21, 1982 under 0F2405; submitted by Diamond Shamrock 

Corp., Cleveland, OH; CDL:071097-B) 

115109 Shults, S.; Killeen, J.; Ignatoski, J. (1981) Dietary Study (LC50) in Bobwhite Quail with DS3701 (4-Hydroxy-2,5,6-trichloroiso- phthalonitrile): Document No. 448-5TX-81-0007-002. 

(Unpublished study received Sep 21, 1982 under 0F2405; submitted by Diamond Shamrock 

Corp., Cleveland, OH; CDL:071097-C) 

71-4 Avian Reproduction 

MRID Citation Reference 

41440 Fink, R. (1976) Final Report: One-Generation Reproduction Study-- Bobwhite Quail: Project 

No. 111-107. (Unpublished study in- cluding submitter summary, received Feb 19, 1980 under 

677-313; prepared by Wildlife International, Ltd., submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:099247-F) 

41441 Fink, R. (1976) Final Report: One-Generation Reproduction Study-- Mallard Duck: Project No. 

111-108. (Unpublished study including submitter summary, received Feb 19, 1980 under 677-
107 

313; pre- pared by Wildlife International, Ltd., submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:099247-G) 

40729401 Shults, S.; Wilson, N.; Killeen, J. (1988) Pilot Reproduction Study in Mallard Ducks with 4-

Hydroxy-2,5,6-trichloroisophthalonitrile Project ID. 230-102. Unpublished study prepared by 

Wildlife International Ltd. and Ricerca, Inc. 134 p. 

40729402 Shults, S.; Wilson, N.; Killeen, J. (1988) Reproduction Study in Mallard Ducks with 4-Hudroxy2,5,6-trichloroisophthalonitrile: Project ID. 230-106. Unpublished study prepared by Wildlife 

International Ltd. and Ricerca, Inc. 193. 

40729403 Shults, S.; Wilson, N.; Killeen, J. (1988) Pilot Reproduction Study in Bobwhite Quail with 4-

Hydroxy-2,5,6-trichloroisophthalonitrile: Project ID. 230-101. Unpublished study prepared by 

Wildlife International Ltd. and Ricerca, Inc. 131 p. 

40729404 Shults, S.; Wilson, N.; Killeen, J. (1988) Reproduction Study in Bobwhite Quail with 4-

Hydroxy-2,5,6-trichloroisophthalonitrile: Project Id. 230-105. Unpublished study prepared by 

Wildlife International Ltd. and Ricerca, Inc. 195 p. 

40964101 Shults, S.; Wilson, N.; Killeen, J. (1988) Pilot Reproduction Study in Mallard Ducks with 

Technical Chlorothalonil: Document No. 1469-87-0003-TX-002. Unpublished study prepared 

by Wildlife In- ternational Ltd. in cooperation with Ricerca, Inc. 138 p. 

40964102 Shults, S.; Wilson, N.; Killeen, J. (1988) Reproduction Study in Mallard Ducks with Technical 

Chlorothalonil: Ricerca--Document No. 1469-87-0004-TX-002. Unpublished study prepared by 

Wild- life International Ltd. in cooperation with Ricerca, Inc. 196 p. 

40964103 Shults, S.; Wilson, N.; Killeen, J. (1988) Pilot Reproduction Study in Bobwhite Quail with 

Technical Chlorothalonil: Ricerca--Docu- ment No. 1469-87-0005-TX-002. Unpublished study 

prepared by Wildlife International Ltd. in cooperation with Ricerca, Inc. 136 p. 

40964104 Shults, S.; Wilson, N.; Killeen, J. (1988) Reproduction Study in Bobwhite Quail with Technical 

Chlorothalonil: Ricerca--Document No. 1469-87/-0006-TX-002. Unpublished study prepared by 

Wild- life International Ltd. in cooperation with Ricerca, Inc. 185 p. 

45710218 Redgrave, V. (1993) Chlorothalonil: Bobwhite Quail Dietary Reproduction and Tolerance 

Studies: Lab Project Number: VCM 11/930496. Unpublished study prepared by Huntingdon 

Research Centre Ltd. 314 p. {OPPTS 850.2300} 

BEES: 

MRID: 77759 

Citation 

Reference: 

Atkins, E.L., Jr.; Anderson, L.D. (1969) Effect of Pesticides on Apiculture: Project No. 1499; 

Research Report CF-4863. Annual rept., Oct 1968. (Unpublished study received Mar 16, 1970 under 

0F0961; prepared by Univ. of California--Riverside, Dept. of Entomology, submitted by Nor-Am 

Agricultural Products, Inc., Naperville, Ill.; CDL:093272-B) 

72-1 Acute Toxicity to Freshwater Fish 

MRID Citation Reference 

87258 McCann, J.A.; Pitcher, F. (1973) ?Bravo TM W-75: Bluegill (?~Lepomis macrochirus?~)|: Test 

No. 548. (U.S. Environmental Protection Agency, Pesticide Regulation Div., Agricultural 

Research Center, Animal Biology Laboratory and Fish Toxicity Laboratory; unpublished study; 

CDL:128550-A) 

87303 Pitcher, F. (1972) ?Tetrachloroisophthalonitrile: Rainbow Trout (?~Salmo gairdneri~?)|: Test 

No. 503. (U.S. Agricultural Re- search Service, Pesticides Regulation Div., Animal Biology 

Lab- oratory; unpublished study; CDL:130256-A) 
108 

87304 Pitcher, F. (1972) ?Tetrachloroisophthalonitrile: Rainbow Trout (?~Salmo gairdneri~?)|: Test 

No. 504. (U.S.Agricultural Re- search Service, Pesticides Regulation Div., Animal Biology 

Labo- ratory; unpublished study; CDL:130254-A) 

42433804 Gelin, M.; Laveglia, J. (1992) Bravo 720--Acute Toxicity to Bluegill Sunfish (Lepomis 

macrochirus) under Flow-Through Conditions: Lab Project Number: 5088-91-0428-TX-002: 

12073. 1091.6110.105: 91-0428. Unpublished study prepared by Ricerca, Inc. and Springborn 

Labs, Inc. 69 p. 

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Trout: Lab Project Number: 258052. Unpublished study prepared by RCC UmweltChemie Ag. 

44 p. 

43302101 Shults, S.; Brock, A.; Laveglia, J. (1994) Acute Toxicity to Rainbow Trout (Oncorhynchus 

mykiss) under Flow-through Conditions with BRAVO 720: Final Report: Lab Project Number: 

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Presence of Sediment: Lab Project Number: RIA 002/983531. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 151 p. 

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VCM 8(B)/920232. Unpublished study prepared by Huntingdon Research Centre Ltd. 25 p. 

{OPPTS 850.1075} 

45710220 Douglas, M. (1992) The Acute Toxicity of Chlorothalonil to Common Carp: Lab Project 

Number: VCM 8(C)/920233. Unpublished study prepared by Huntingdon Research Centre Ltd. 

24 p. {OPPTS 850.1075} 

72-2 Acute Toxicity to Freshwater Invertebrates 

MRID Citation Reference 

68754 LeBlanc, G.A. (1977) Acute Toxicity of DTX-77-0072 to the Water Flea (~Daphnia magna~). 

(Unpublished study, including submit- ter summary, received Jan 19, 1978 under 677-229; 

prepared by EG & G, Bionomics, submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:232729-B) 

42433806 Gelin, M.; Laveglia, J. (1992) Bravo 720--Acute Toxicity to Daphnids (Daphnia magna) under 

Flow-through Conditions: Lab Project Number: 5087-91-0427-TX-002: 12073.1091.6108.115: 

91-0427. Unpublished study prepared by Springborn Labs, Inc. and Ricerca, Inc. 135 p. 

45425801 Forster, A. (1998) Toxicity of Chlorothalonil to the Sediment Dwelling Phase of the Midge 

Chironomus Riparius: Lab Project Number: RIA 1/974025. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 54 p. 

45425802 Forster, A. (1998) Chlorothalonil: Assessment of Acute Toxicity to Daphnia Magna in the 

Presence of Sediment: Lab Project Number: RIA 003/982279. Unpublished study prepared by 

Huntingdon Life Sciences Ltd. 150 p. 

45710221 Douglas, M. (1992) The Acute Toxicity of Chlorothalonil to Daphnia magna: Lab Project 

Number: VCM 8(A)/920231. Unpublished study prepared by Huntingdon Research Centre Ltd. 

24 p. {OPPTS 850.1010} 

72-3 Acute Toxicity to Estuarine/Marine Organisms 

MRID Citation Reference 

127863 Ward, S.; Shults, S.; Killeen, J.; et al. (1982) Static Acute Toxicity Study in Sheepshead 
109 

Minnows with Technical Chlorothalonil: Document No. 537-5TX-82-0053-002. (Unpublished 

study received Apr 21, 1983 under 677-313; submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, OH; CDL:071552-B) 

127864 Ward, S.; Shults, S.; Killeen, J.; et al. (1982) Static Acute Toxicity Study in Penaeid (Pink) 

Shrimp with Technical Chloro- thalonil: Document No. 537-5TX-82-0054-002. (Unpublished 

study received Apr 21, 1983 under 677-313; submitted by Diamond Sham- rock Agricultural 

Chemicals, Cleveland, OH; CDL:071552-C) 

127865 Armstrong, D.; Buchanan, D.; Caldwell, R. (1976) A mycosis caused by lagenidium sp. in 

laboratory-reared larvae of the dungeness crab, cancer magister, and possible chemical 

treatments. Jour- nal of Invertebrate Pathology 28:329-336. (Also In unpublished submission 

received Apr 21, 1983 under 677-313; submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, OH; CDL: 071552-D) 

138143 Ward, G.; Shuba, P. (1983) Acute Toxicity of T-117-11 to Eastern Oysters (Crassostrea 

virginica): Report No. BP-83-2-25. (Un- published study received Jan 10, 1984 under 50534-8; 

prepared by EG & G Bionomics, submitted by SDS Biotech Corp., Painesville, OH; 

CDL:072266-A) 

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

MRID Citation Reference 

29410 Szalkowski, M.B.; Stallard, D.E.; Bachand, R.T., Jr. (1979) Acute Toxicity of 2,4,5,6-

Tetrachloroisophthalonitrile (Chlorothalo- nil) to Bluegill Sunfish (?~Lepomis macrochirus~?): 

Research Re- port R-79-0003. (Unpublished study received Feb 19, 1980 under 677-313; 

submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:099248-H) 

29415 Szalkowski, M.B.; Stallard, D.E.; Bachand, R.T., Jr. (1979) Acute Toxicity of 4-Hydroxy-2,5,6-

trichloroisophthalonitrile (DS-3701) to Bluegill Sunfish (?~Lepomis macrochirus~?): Research 

Report R-79-0004. (Unpublished study received Feb 19, 1980 under 677- 313; submitted by 

Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:099248-M) 

30390 Shults, S.K.; Killeen, J.C., Jr.; Heilman, R.D.; et al. (1980) Chlorothalonil (Technical) Acute 

Toxicity (LCI50^) Study in Channel Catfish. (Unpublished study including report # BW-79-6- 

460, received Feb 19, 1980 under 677-313; prepared in coopera- tion with EG&G, Bionomics, 

submitted by Diamond Shamrock Agri- cultural Chemicals, Cleveland, Ohio; CDL:099247-E) 

30393 Buccafusco, R.J. (1977) Acute Toxicity of DTX-77-0070 to Bluegill (?~Lepomis 

macrochirus~?). (Unpublished study including sub- mitter summary, received Feb 19, 1980 

under 677-313; prepared by EG&G, Bionomics, submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:099247-L) 

39145 Dieterich, W.H. (1965) Acute Aqueous Exposure--Fish: Project No. 200-164. (Unpublished 

study received Feb 25, 1976 under 6F1749; prepared by Hazleton Laboratories, Inc., submitted 

by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL: 096459-A) 

41439 Shults, S.K.; Killeen, J.C., Jr.; Heilman, R.D.; et al. (1980) Chlorothalonil (Technical) Acute 

Toxicity (LCI50^) Study in Bluegill. (Unpublished study including report # BW-79-6-446, 

received Feb 19, 1980 under 677-313; prepared in cooperation with EG&G, Bionomics, 

submitted by Diamond Shamrock Agricul- tural Chemicals, Cleveland, Ohio; CDL:099247-D) 

56486 Shults, S.K.; Killeen, J.C., Jr.; Heilman, R.D. (1980) Chlorothalo- nil (Technical) Acute 

Toxicity (LCI50^) Study in Rainbow Trout. (Unpublished study including report # BW-79-6-

461, re- ceived Feb 19, 1980 under 677-313; prepared in cooperation with EG&G, Bionomics, 

submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:099247-C) 

115107 Shults, S.; Killeen, J.; Ignatoski, J. (1982) Chronic Toxicity Study in Daphnia magna with 
110 

Technical Chlorothalonil: Document No. 447-5TX-81-0006-002. (Unpublished study received 

Sep 21, 1982 under 0F2405; submitted by Diamond Shamrock Corp., Cleve- land, OH; 

CDL:071097-A) 

42433807 Shults, S.; Brock, A.; Laveglia, J. (1991) Flow-through Life-Cycle Toxicity Test in Mysid 

Shrimp with Technical Chlorothalonil: Lab Project Number: 3228-89-0043-TX-002: 12073. 

0289. 6100. 530: 90-05-3330. Unpublished study prepared by Springborn Labs, Inc. and 

Ricerca, Inc. 103 p. 

42924901 Surprenant, D. (1993) Individual Growth Data for First Generation Male and Female Shrimp for 

the Study, "Flow-through Life-cycle Toxicity Test in Mysid Shrimp with Technical 

Chlorothalonil," (MRID #42433807; Doc. No. (3228-89-0043-TX-002): Lab Project Number: 

FW-93-RPB-004-001. Unpublished study prepared by Springborn Labs., Inc. 6 p. 

45710222 Douglas, M. (1992) An Assessment of the Effects of Chlorothalonil on the Reproduction of 

Daphnia magna: Lab Project Number: VCM 8(E)/920814. Unpublished study prepared by 

Huntingdon Research Centre Ltd. 65 p. {OPPTS 850.1500} 

72-6 Aquatic org. accumulation 

MRID Citation Reference 

43070601 Kabler, K.; Quinn, B. (1993) Chlorothalonil: Bioconcentration Test with the Eastern Oyster, 

Crassostrea virginica, Under Flow-Through Conditions: Lab Project Number: J9205003. 

Unpublished study prepared by Toxikon Environmental Sciences. 68 p. 

72-7 Simulated or Actual Field Testing 

MRID Citation Reference 

44286001 Ernst, W.; Doe, K.; Jonah, P. et al. (1991) The toxicity of chlorothalonil to aquatic fauna and the 

impact of its operational use on a pond ecosystem. Archives of Environmental Contamination 

and Toxicology 21:1-9. 

44453501 Ernst, W.; Doe, K.; Jonah, P. et al. (1991) The toxicity of chlorothalonil to aquatic fauna and the 

impact of its operational use on a pond ecosystem. Archives of Environmental Contamination 

and Toxicology 21:1-9. 

81-1 Acute oral toxicity in rats 

MRID Citation Reference 

11514 Perkins, C.T. (1975) Acute Oral Toxicity of DTX-75-0018 in Male and Female Albino Rats: 

Project Number: 27-216. (Unpublished study received Jan 27, 1976 under 677-EX-13; prepared 

by Bio/Tox Re- search Laboratories, Inc., submitted by Diamond Shamrock Agri- cultural 

Chemicals, Cleveland, Ohio; CDL:227752-D) 

11515 Perkins, C.T. (1975) Acute Oral Toxicity of DTX-75-0019 in Male and Female Albino Rats: 

Project Number: 27-219. (Unpublished study received Jan 27, 1976 under 677-EX-13; prepared 

by Bio/Tox Labo- ratories, Inc., submitted by Diamond Shamrock Agricultural Chem- icals, 

Cleveland, Ohio; CDL:227752-H) 

14430 Perkins, C.T. (1975) Acute Dermal Toxicity of DTX-75-0018 in Albino Rabbits: Project 

Number: 27-214. (Unpublished study received Jan 27, 1976 under 677-EX-13; prepared by 

Bio/Tox Research Laboratories, Inc., submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:227752-E) 

14431 Perkins, C.T. (1975) Acute Eye Irritation of DTX-75-0018 in Albino Rabbits with and without 

Washing: Project Number: 27-215. (Un- published study received Jan 27, 1976 under 677-EX-
111 

13; prepared by Bio/Tox Research Laboratories, Inc., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, Ohio; CDL:227752-F) 

14432 Perkins, C.T. (1975) Acute Dermal Toxicity of DTX-75-0019 in Albino Rabbits: Project 

Number: 27-217. (Unpublished study received Jan 27, 1976 under 677-EX-13; prepared by 

Bio/Tox Research Labo- ratories, Inc., submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:227752-I) 

14433 Perkins, C.T. (1975) Acute Eye Irritation of DTX-75-0019 in Albino Rabbits with and without 

Washing: Project Number: 27-218. (Un- published study received Jan 27, 1976 under 677-EX13; prepared by Bio/Tox Research Laboratories, Inc., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, Ohio; CDL:227752-J) 

30353 Braun, W.G.; Rinehart, W.E. (1979) Acute Oral Toxicity Study in Rats: Project No. 5121-78. 

(Unpublished study including submit- ter summary, received Feb 19, 1980 under 677-313; 

prepared by Bio/dynamics, Inc., submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:099244-D) 

30357 Braun, W.G.; Rinehart, W.E. (1978) Acute Oral Toxicity Study in Rats: Compound: T-118-1: 

Project No. 5124-78. (Unpublished study including submitter summary, received Feb 19, 1980 

under 677-313; prepared by Bio/dynamics, Inc., submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:099244-H) 

38909 Doyle, R.L.; Elsea, J.R. (1963) Acute Oral, Dermal, and Eye Toxici- ty and Irritation Studies on 

DAC-2787: N-107. (Unpublished study received Feb 25, 1976 under 6F1749; prepared by Hill 

Top Research Institute, Inc., submitted by Diamond Shamrock Agricul- tural Chemicals, 

Cleveland, Ohio; CDL:096457-A) 

38910 Powers, M.B. (1965) Acute Oral Administration--Rats: Project No. 200-167. (Unpublished 

study received Feb 25, 1976 under 6F1749; prepared by Hazleton Laboratories, Inc., submitted 

by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL: 096457-B) 

38911 Paynter, O.E. (1965) Final Report: Oral Dose Range--Dogs: Project No. 200-168. (Unpublished 

study received Feb 25, 1976 under 6F1749; prepared by Hazleton Laboratories, Inc., submitted 

by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL: 096457-C) 

42447 Piccirillo, V.J.; Leatherwood, L.; Shopp, G. (1979) Acute Oral Toxicity (LDI50^) Study in Rats 

with T-126-1: Project No. 209-C. Final rept. (Unpublished study received Sep 2, 1980 under 

2204- 17, prepared by Borriston Research Laboratories, Inc., submitted by Diamond Shamrock 

Corp., Morristown, N.J.; CDL:243157-C) 

47937 Wazeter, F.X.; Goldenthal, E.I.; Dean, W.P. (1971) Acute Oral LDI50^ in Male Albino Rats: 

IRDC No. 293-004. (Unpublished study received Dec 8, 1976 under 677-313; prepared by 

Interna- tional Research and Development Corp., submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:095783-B) 

47938 Hastings, T.F. (1973) AOLDI50^ in S-D Rats Using DAC-3701. (Unpub- lished study received 

Dec 8, 1976 under 677-313; prepared by Bio/Tox Research Laboratories, Inc., submitted by 

Diamond Sham- rock Agricultural Chemicals, Cleveland, Ohio; CDL:095783-C) 

47939 Wazeter, F.X.; Goldenthal, E.I.; Dean, W.P. (1972) Acute Oral Tox- icity (LDI50^) in Beagle 

Dogs: IRDC No. 239-021. (Unpublished study including letter dated Oct 13, 1972 from E.I. 

Goldenthal to Milton Eisler, received Dec 8, 1976 under 677-313; prepared by International 

Research and Development Corp., submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL: 095783-D) 

55020 Dean, W.P. (1976) Acute Oral Toxicity (LDI50^) Study in Male and Female Albino Rats: IRDC 

No. 293-050. (Unpublished study re- ceived Sep 23, 1976 under 6G1871; prepared by 

International Re- search and Development Corp., submitted by Diamond Shamrock Ag- 
112 

ricultural Chemicals, Cleveland, Ohio; CDL:095293-G) 

61443 WARF Institute, Incorporated (1975) Report: WARF No. 5010231. Summary of studies 

228211-C through 228211-F. (Unpublished study received Jun 17, 1975 under 538-139; 

submitted by O.M. Scott & Sons Co., Marysville, Ohio; CDL:228211-B) 

61444 WARF Institute, Incorporated (1975) Acute Oral Toxicity: WARF No. 5010231. (Unpublished 

study received Jun 17, 1975 under 538-139; submitted by O.M. Scott & Sons Co., Marysville, 

Ohio; CDL:228211-C) 

70357 Chevron Chemical Company (1974) Summary: Toxicology for Ortho Liq- uid Lawn Disease 

Control (Chlorothalonil 2.88 Flowable). Sum- mary of studies 232607-B through 232607-L. 

(Unpublished study received Nov 23, 1976 under 239-2432; CDL:232607-A) 

70358 Rittenhouse, J.R.; Narcisse, J.K. (1974) The Acute Oral Toxicity of Daconil 2.88F to Adult 

Male and Female Rats: SOCAL 571/XVIII:75 (S-669). (Unpublished study received Nov 23, 

1976 under 239- 2432; submitted by Chevron Chemical Co., Richmond, Calif.; CDL:232607-B) 

87306 Heenehan, P.R.; Braun, W.G.; Rinehart, W.E. (1977) Acute Oral Tox- icity Study: Project No. 

4501-77. (Unpublished study, including submitter summary, received Oct 24, 1978 under 677-

315; prepared by Bio/dynamics, Inc., submitted by Diamond Shamrock Agricul- tural 

Chemicals, Cleveland, Ohio; CDL:235370-A) 

87322 WARF Institute, Incorporated (1973) Report: WARF No. 3091600. (Un- published study 

received Feb 6, 1974 under 538-114; submitted by O.M. Scott & Sons Co., Marysville, Ohio; 

CDL:023130-D) 

91284 Paynter, O.E. (1965) Final Report: Oral Dose Range--Dogs: Project No. 200-168. (Unpublished 

study received May 17, 1967 under 7F0599; prepared by Hazleton Laboratories, Inc., submitted 

by Diamond Alkali Co., Cleveland, Ohio; CDL:090769-B) 

92411 Goldenthal, E.I.; Wazeter, F.X.; Dean, W.P. (1972) Acute Oral Toxicity (LDI50^) in Beagle 

Dogs: 293-021. (Unpublished study, including letter dated Oct 13, 1972 from E.I. Goldenthal to 

Milton Eisler, received on unknown date under 2F1230; prepared by International Research and 

Development Corp., submitted by Diamond Shamrock Chemical Co., Cleveland, Ohio; 

CDL:091081-B) 

94728 Moreno, M.T.; Lundberg, D.; Killeen, J.C., Jr.; et al. (1980) Acute Oral (LD\50^) Toxicity Study 

in Rats with Nopcocide N-96: Docu- ment No. 103-5TX-79-0057-002; prepared in cooperation 

with MB Research Laboratories, Inc. Unpublished study; 13 p. 

94941 Shults, S.K.; Killeen, J.C., Jr.; Ignatoski, J.A. (1981) Acute Oral Toxicity (LDI50^) Study in 

Rats with Technical Chlorothalonil: Document No. 296-5TX-80-0092-002. (Unpublished study 

received Feb 22, 1982 under 677-283; submitted by Diamond Shamrock Agricultural 

Chemicals, Cleveland, Ohio; CDL:246843-C) 

105964 Bottoms, J. (1981) Oral Toxicity--EPA 40 CFR 163.81-1 Proposed: ?Germain's Lawn and 

Garden Fungicide|: Laboratory No. 17480. (Unpublished study received May 12, 1982 under 

6993-61; pre- pared by Applied Biological Sciences Laboratory, submitted by Germain's, Inc., 

Los Angeles, CA; CDL:247763-A) 

120333 Cannelongo, B.; Sabol, E.; Sabol, R. (1982) Rat Acute Oral Toxici- ty: Bravo 500/Sulphur 6 

50:50 072382-A: Project No. 2781-82. (Unpublished study received Dec 9, 1982 under 5905-

472; pre- pared by Stillmeadow, Inc., submitted by Helena Chemical Co., Memphis, TN; 

CDL:249039-A) 

126494 Perkins, C.; Dickson, M. (1975) Acute Oral Toxicity of DTX-75-0018 in Male and Female 

Albino Rats: Project No. 27-216. (Unpub- lished study received Jan 27, 1976 under unknown 

admin. no.; prepared by Bio/Tox Research Laboratories, Inc., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, OH; CDL: 249762-A) 
113 

126497 Perkins, C.; Dickson, M. (1975) Acute Oral Toxicity of DTX-75-0019 in Male and Female 

Albino Rats: Project No. 27-219. (Unpub- lished study received Jan 27, 1976 under unknown 

admin. no.; prepared by Bio/Tox Research Laboratories, Inc., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, OH; CDL: 249762-D) 

136963 Mastri, C. (1971) Report to ...: Acute Toxicity Studies with Dac- onil-Dexon 40-32, Seed 

Protectant--7385-21: IBT No. A9419. (Un- published study received Feb 19, 1971 under 677-

311; prepared by Industrial Bio-Test Laboratories, Inc., submitted by Diamond Shamrock 

Agricultural Chemicals, Cleveland, OH; CDL:004258-C) 

137703 Dunn, G.; Guidi, L. (1981) Acute Oral Range Finding Determination Performed on 9660-1: 

Bioassay Systems Corp. Project No. 10656. (Unpublished study received Feb 14, 1984 under 

518-71; prepared by Bioassay Systems Corp., submitted by Darworth, Inc., Avon, CT; 

CDL:252618-A) 

137949 Penick Corp. (19??) Acute LD50 Values Were Determined for 3 Pesti- cides and the Synergist 

Sulfoxide. (Unpublished study received Jan 15, 1973 under 432-502; CDL:003351-N) 

141697 Major, D. (1983) Acute Oral Toxicity LD50 Study in Rats with Chlo- rothalonil 90 DG: 

Document No: 620-5TX-83-0019-002. Unpublished study prepared by Diamond Shamrock 

Corporation and Toxicol/Sisa, Inc. 49 p. 

145529 Sabol, E. (1982) Rat Acute Oral Toxicity: Bravo 500/Sulphur 6 50:50 072382-A: Project No. 

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147071 James, C. (1985) Acute Oral Toxicity (LD50) Study in Rats with Chlorothalonil + Copper + 

Maneb (WDG) Formulation: Report No: TEK/0018/P1105/0. Unpublished study prepared by 

Sisa Toxicolo- gical Laboratories, Inc. 83 p. 

147868 Schiavo, D.; Breckenridge, C.; Grewen, J. (1985) Acute Oral Toxici- ty Study in Male & Female 

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152530 Davis, T. (1985) Acute Oral Toxicity Screen [Olympic Semi-Transpa- rent Weather Screen]: 

Lab No. 59425. Unpublished study prepared by Mideco, Inc. 45 p. 

154287 Shults, S. (1985) Acute Oral Toxicity (LD50) Study in Rats with Chlorothalonil + Oxadixyl 

(WDG) Formulation: Report Document No.: 738-5TX-85-0016-002. Unpublished study 

prepared by SDS Biotech Corp. and SISA Toxicological Laboratories, Inc. 49 p. 

160358 Levitz, E. (1985) Acute Oral Toxicity Study in Rats: Test Mate- rial: Chlorothalonil 90DF: 

Project No. 5969-85. Unpublished study prepared by Bio/dynamics Inc. 9 p. 

162383 Savides, M. (1986) Identification of Metabolites in Urine and Blood following Oral 

Administration of [Carbon 14]-Chlorothanolin ([Carbon 14]-SDS-2787) Male Rats: II. Effects 

of Multiple Dose Administration on the Excretion of Thiol Metabolites in Urine Excretion of 

Thiol Metabolites in Urine: Report/SDS-2787: Docu- ment No. 621-4AM-83-0061-002. 

Unpublished study prepared by SDS Biotech Corp. 72 p. 

40243702 Ford, W.; Killeen, J. (1987) A 90-day Feeding Study in Rats with Chlorothalonil: Supplemental 

Data: Document No.: 1115-85-0079- TX-006; Project ID: 293-144. Unpublished study prepared 

by Ricerca, Inc. in cooperation with International Research and Development Corp.; 

Experimental Pathology Laboratories, Inc.; and Laboratoire d'histopathologie, C.E.R.T.I. 464 p. 

40405102 Gabriel, D. (1987) Consyst Turf Fungicide - Acute Oral Toxicity, Single Level - Rats: Proj. No. 

87-5495A. Unpublished study pre- pared by Biosearch Inc. 8 p. 

40459605 Reagan, E. (1987) Acute Oral Toxicity Study of Flexgard III in Sp- rague Dawley Rats: Lab. 

Proj. ID 9537-A. Unpublished study pre- pared by Food & Drug Research Laboratories, Inc. 35 

p. 
114 

40461002 Siglin, J. (1987) Acute Oral Toxicity Study of Ole' K in Rats: Lim- it Test (EPA): SLS Study 

No. 3159.10. Unpublished study pre- pared by Springborn Life Sciences, Inc. 25 p. 

40461003 Siglin, J. (1987) Acute Oral Toxicity Study of Ole' K in Rats: LD50 Test (EPA): SLS Study No. 

3159.23. Unpublished study prepared by Springborn Life Sciences, Inc. 85 p. 

40509901 Siglin, J. (1987) Acute Oral Toxicity Study of Flowable Chloro- thalonil in Rats (EPA): Study 

No. 3159.5.1. Unpublished study prepared by Springborn Institute for Bioresearch, Inc. 25 p. 

40703904 Kuhn, J. (1988) Acute Oral Toxicity Study in Rats: Lesco Two-Some Flowable Fungicide: Proj. 

No. 5339-88. Unpublished study pre- pared by Stillmeadow, Inc. 19 p. 

40956504 Myers, R.; Christopher, S. (1988) Woolsey Lumaguard Anti-fouling Finish 680 Blue: Acute 

Toxicity and Primary Irritation Studies: Laboratory Project ID: 51-594. Unpublished 

compilation prepared by Union Carbide, Bushy Run Research Center. 25 p. 

41206011 Shults, S.; Wilson, N.; Killeen, J. (1989) Acute Oral Toxicity (LD50) Study in Rats with 

Tuffcide 500: Project ID: 88-0051; Document No. 3034-88-0051-TX-001. Unpublished study 

prepared by Ricerca, Inc. 37 p. 

41564801 Shults, S.; Long, M.; Wilson, N. (1985) Acute Oral Toxicity Screen- ing in Rats with SDS46851: Lab Project Number: 684-5TX-84-0033- 001. Unpublished study prepared by SDS 

Biotech Corp. 31 p. 

41756602 Kuhn, J. (1990) Acute Oral Toxicity Study in Rats: Chlorothalonil 6L: Lab Project Number: 

7098-90. Unpublished study prepared by Stillmeadow, Inc. 11 p. 

41822103 Shults, S.; Brock, A.; Kileen, J. (1990) Acute Oral Toxicity (LD50) Study in Rats with ASC66779-0101-0701: Lab Project Number: 2051 -89-0376-TX-001: 89-0376. Unpublished study 

prepared by Ricerca , Inc. 37 p. 

41978401 Robbins, G. (1991) Acute Oral Toxicity in Rats: Funginil Lawn and Garden Fungicide: Lab 

Project Number: A3159. Unpublished study prepared by Cosmopolitan Safety Evaluation, Inc. 

19 p. 

42148514 Shults, S.; Brock, A.; Killeen, J. (1991) Acute Oral Toxicity Study in Rats with ASC-66518-

0101-1203: Lab Project Number: 3780-91-0030-TX-001: 91-0030. Unpublished study prepared 

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42325604 Shults, S.; Brock, A.; Killeen, J. (1990) Acute Oral Toxicity (LD50) Study in Rats with ASC66792-X-0104: Lab Project Number: 90-0170. Unpublished study prepared by Ricerca, Inc. 47 

p. 

42493401 Cerven, D. (1991) Single Dose Oral Toxicity in Rats/LD 50 in Rats: Compound SO-1 

Chlorothalonil 75 W D G Lab Project Number: MB 91-778 A. Unpublished study prepared by 

MB Research Laboratories Inc. 29 p. 

42552504 Cerven, D. (1992) Single Dose Oral Toxicity in Rats/LD50 in Rats: SO-2, Chlorothalonil 

Flowable 40.8%: Lab Project Number: MB 91-924 A. Unpublished study prepared by MB 

Research Labs, Inc. 24 p. 

42670002 Gabriel, D. (1992) Acute Oral Toxicity, Two Levels--Rats: ConSyst (chlorothalonil and 

thiophanate methyl): Lab Project Number: 92-7558A. Unpublished study prepared by Biosearch 

Inc. 15 p. 

42683101 Kuhn, J. (1992) Acute Oral Toxicity Study in Rats: Chlorothalonil 4L, Flowable Agricultural 

Fungicide: Lab Project Number: 9401-92. Unpublished study prepared by Stillmeadow, Inc. 20 

p. 

42789404 Shults, S.; Brock, A.; Killeen, J. (1991) Acute Oral Toxicity (LD50) Study in Rats with ASC64216-0101-0301: Lab Project Number: 91-0025: 3779-91-0025-TX-001. Unpublished study 
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42864801 Kukulinski, M. (1993) Acute Oral Toxicity Study: Yard Guard: Final Report: Lab Project 

Number: 93-98-1. Unpublished study prepared by Tox Monitor Labs, Inc. 9 p. 

42871701 Kuhn, J. (1993) Acute Oral Toxicity Study in Rats: Chlorothalonil Flowable 720: Lab Project 

Number: 9895-93. Unpublished study prepared by Stillmeadow, Inc. 18 p. 

42976104 Kuhn, J. (1993) Acute Oral toxicity Study in Rats: Export (ASC-67097): Lab Project Number: 

9055-92. Unpublished study prepared by Stillmeadow, Inc. 24 p. 

42979104 Parcell, B.; McRae, L. (1993) Acute Oral Toxicity to the Rat of SR2040 (Proposed ACTICIDE 

PM) (Diuron, Chlorothalonil): Lab Project Number: THR 24/930085/AC. Unpublished study 

prepared by Huntingdon Research Centre Ltd. 19 p. 

43041202 Kuhn, J. (1993) Acute Oral Toxicity Study in Rats: Dragon Rose and Flower Dust: Lab Project 

Number: 0394-93. Unpublished study prepared by STILLMEADOW, Inc. 21 p. 

43142005 Gabriel, D. (1992) Acute Oral Toxicity, LD-Rats: ConSyst 4FL: Lab Project Number: 

92/7571A. Unpublished study prepared by Biosearch Inc. 23 p. 

43520202 Wnorowski, G. (1994) Acute Oral Toxicity Limit Test (in Rats): Chlorothalonil 90D: Lab 

Project Number: 3135: P320. Unpublished study prepared by Product Safety Labs. 16 p. 

43594004 Shults, S.; Brock, A.; Laveglia, J. (1994) ASC 66783: Acute Oral Toxicity (LD50) Study in Rats 

With Chlorothalonil Plus Flutolanil (ASC 66783-0201-0202): Lab Project Number: 5933-93-

0350-TX-001. Unpublished study prepared by Ricerca, Inc. 42 p. 

43622601 Wnorowski, G. (1995) Acute Oral Toxicity Defined LD50 (in Rats): Chlorothalonil & Sulphur 

Fungicide: Lab Project Number: 3453: P320. Unpublished study prepared by Product Safety 

Labs. 26 p. 

43646603 Shults, S.; Brock, A.; Laveglia, J. (1992) Acute Oral Toxicity (LD50) Study in Rats with ASC 

67114-0101-0101: Lab Project Number: ASC-67114-0101-0101: 1081-92-0237-AS-001: 5323-

92-0201-TX-001. Unpublished study prepared by Ricerca, Inc. 56 p. 

43678401 Kuhn, J. (1992) Acute Oral Toxicity Study in Rats: Chlorothalonil Technical: Lab Project 

Number: 9374-92. Unpublished study prepared by Stillmeadow, Inc. 12 p. 

43793301 McRae, L. (1995) SR 2040 (Acticide PM): Acute Oral Toxicity to the Rat: Lab Project Number: 

THR/33: THR/33/951611/AC. Unpublished study prepared by Huntingdon Research Centre Ltd. 

16 p. 

43800324 Kuhn, J. (1995) Acute Oral Toxicity Study in Rats: CGA-32951/CT 76.5 WP: Final Report: Lab 

Project Number: 2014-95. Unpublished study prepared by Stillmeadow, Inc. 39 p. 

43809202 Wnorowski, G. (1995) Acute Oral Toxicity Defined LD50 (in Rats): Terranil & Copper: Lab 

Project Number: 3815: P320. Unpublished study prepared by Product Safety Labs. 27 p. 

44044204 Shults, S.; Brock, A.; Laveglia, J. (1995) Acute Oral Toxicity (LD50) Study in Rats with 

Dacobre (ASC-67213-0101-0101): Lab Project Number: 6275-94-0208-TX-002: 94-0208: 

6275-94-0208-TX-001. Unpublished study prepared by Ricerca, Inc. 88 p. 

44064601 Denton, S. (1992) T81 Propamocarb-HCL: Rat Acute Oral Toxicity Study: Lab Project Number: 

920530D/SMS 411/AC: TOX/92/186-19: TOX 92156. Unpublished study prepared by 

Huntingdon Research Centre Ltd. 23 p. 

44071104 Wnorowski, G. (1995) Acute Oral Toxicity Defined LD50 (in Rats): BP-1007: Lab Project 

Number: 3421: P320. Unpublished study prepared by Product Safety Labs. 28 p. 

44079802 Glaza, S. (1996) Acute Oral Toxicity Study of EXP-10673A in Rats: Final Report: Lab Project 
116 

Number: CHW 50302780: TP3013R: 50302780. Unpublished study prepared by Corning 

Hazleton Inc. 40 p. 

44412201 Bomann, W. (1993) Study on the Acute Oral Toxicity in Rats: Tebuconazole and 

Chlorothalonile: Lab Project Number: 22696: T 5044160. Unpublished study prepared by Bayer 

Ag. 40 p. 

44420401 Kuhn, J. (1997) Acute Oral Toxicity in Rats: NeXgen: Lab Project Number: 3580-97: S9-FF81-

1. Unpublished study prepared by Stillmeadow, Inc. 21 p. 

44993203 Wnorowski, G. (1999) Acute Oral Toxicity Study in Rats--Limit Test: GX-611001E: Lab 

Project Number: 7703: P320. Unpublished study prepared by Product Safety Labs. 17 p. 

{OPPTS 870.1100} 

45038501 Moore, G. (1999) Acute Oral Toxicity Study in Rats: Spectro 90 WDG: Lab Project Number: 

8116: P320. Unpublished study prepared by Product Safety Labs. 20 p. {OPPTS 870.1100} 

45049103 Moore, G. (2000) Acute Oral Toxicity Study in Rats--Limit Test: GX-612/Equus DF: Lab 

Project Number: 8136: P320. Unpublished study prepared by Product Safety Labs. 15 p. 

{OPPTS 870.1100} 

45077801 Kuhn, J. (1998) Acute Oral Toxicity Study in Rats: IBC 4A: Final Report: Lab Project Number: 

3852-97. Unpublished study prepared by Stillmeadow, Inc. 20 p. 

45077802 Kuhn, J. (1997) Acute Oral Toxicity Study in Rats: IBC 4B: Final Report: Lab Project Number: 

3853-97. Unpublished study prepared by Stillmeadow, Inc. 22 p. 

45077803 Kuhn, J. (1998) Acute Oral Toxicity Study in Rats: IBC 4C: Final Report: Lab Project Number: 

3854-97. Unpublished study prepared by Stillmeadow, Inc. 18 p. 

45077804 Kuhn, J. (1998) Acute Oral Toxicity Study in Rats: IBC 4D: Final Report: Lab Project Number: 

3855-97. Unpublished study prepared by Stillmeadow, Inc. 18 p. 

45082801 Auletta, C. (1985) Acute Oral Toxicity: Terranil 90DF (in Rats): Lab Project Number: 5971-85. 

Unpublished study prepared by Bio/dynamics, Inc. 11 p. {OPPTS 870.1100} 

45105603 Merkel, D. (2000) Acute Oral Toxicity in Rats--Limit Test of Cuprinol Siding & Stain 

Preservative: Lab Project Number: 8749: P320. Unpublished study prepared by Product Safety 

Labs., Inc. 14 p. {OPPTS 870.1100} 

45105604 Merkel, D. (2000) Acute Oral Toxicity in Rats--Limit Test of Cuprinol Siding & Stain 

Preservative: Lab Project Number: 8755: P320. Unpublished study prepared by Product Safety 

Labs., Inc. 14 p. {OPPTS 870.1100} 

45134401 Moore, G. (2000) Acute Oral Toxicity Study in Rats--Limit Test: Allpro Exotherm Termil: Lab 

Project Number: 8915. Unpublished study prepared by Product Safety Labs. 15 p. {OPPTS 

870.1100} 

45162202 Kuhn, J. (2000) Acute Oral Toxicity Study in Rats: Chlorothalonil 51% Flowable: Final Report: 

Lab Project Number: 5836-00. Unpublished study prepared by Stillmeadow, Inc. 11 p. {OPPTS 

870.1100} 

45163901 Moore, G. (2000) Acute Oral Toxicity Study in Rats: (Chlorothalonil): Lab Project Number: 

PSL-8730: P320.ZEN.CHLORO. Unpublished study prepared by Product Safety Labs. 21 p. 

{OPPTS 870.1100} 

45339801 Merkel, D. (2001) Acute Oral Toxicity Study in Rats-Limit Test: Bio-Flex: Lab Project Number: 

10003: P320. Unpublished study prepared by Product Safety Labs. 14 p. {OPPTS 870.1100} 

45464702 Merkel, D. (2001) Acute Oral Toxicity Study in Rats--Limit Test: Intace B-6773: Lab Project 

Number: 10552. Unpublished study prepared by Product Safety Labs. 16 p. {OPPTS 870.1100} 
117 

45507302 Freemantle, M. (2001) BP 1040: Acute Oral Toxicity Study in the Rat: Final Report: Lab Project 

Number: 1803/16-D6144. Unpublished study prepared by Covance Laboratories Ltd. 31 p. 

{OPPTS 870.1100} 

45559703 Moore, G. (2001) Acute Oral Toxicity Study in Rats--Limit Test: Taratek 5F: Lab Project 

Number: 10601: P320. Unpublished study prepared by Product Safety Labs. 15 p. {OPPTS 

870.1100} 

45606004 Kuhn, J. (2001) Acute Oral Toxicity Study in Rats: Echo Home Garden Fungicide & Insecticide: 

Final Report: Lab Project Number: 6401-01. Unpublished study prepared by Stillmeadow, Inc. 

14 p. {OPPTS 870.1100} 

45710203 Cummins, H. (1988) Chlorothalonil Technical: Acute Oral Toxicity Study in the Rat: Lab 

Project Number: 88/CFA002/276. Unpublished study prepared by Life Science Research. 19 p. 

{OPPTS 870.1100} 

83-4 2-generation repro.-rat 

MRID Citation Reference 

38912 Paynter, O.E. (1966) Reproduction--Rabbits: DAC 2787: Project No. 200-176. (Unpublished 

study received Feb 25, 1976 under 6F1749; prepared by Hazleton Laboratories, Inc., submitted 

by Diamond Shamrock Agricultural Chemicals, Cleveland, Ohio; CDL:096457-D) 

38913 Paynter, O.E.; Kundzin, M.; Crews, L.M. (1967) Final Report: Three- Generation Reproduction 

Study--Rats: Project No. 200-150. (Un- published study received Feb 25, 1976 under 6F1749; 

prepared by Hazleton Laboratories, Inc., submitted by Diamond Shamrock Agri- cultural 

Chemicals, Cleveland, Ohio; CDL:096457-E) 

38914 Paynter, O.E.; Kundzin, M. (1967) Final Report: Three-Generation Reproduction Study--Rats: 

Project No. 200-155. (Unpublished study received Feb 25, 1976 under 6F1749; prepared by 

Hazleton Laboratories, Inc., submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL:096457-F) 

42095 Budny, J.A. (1976) Letter sent to E.M. Wilson dated Dec 2, 1976 ?Points of clarification on 

Bravo 6F in response to phone con- versations 11/23/76 and 11/24/76 between Dr. Coberly 

(EPA) and Dr. Budny (Diamond Shamrock)|. (Unpublished study received Dec 8, 1976 under 

677-313; submitted by Diamond Shamrock Agri- cultural Chemicals, Cleveland, Ohio; 

CDL:095783-E) 

47946 Hastings, T.F.; Ferrell, J.F. (1975) 3-Generation Reproduction Study in Albino Rats: Dac-3701: 

Study No. 24-051A. Final rept. (Unpublished study including submitter summary, received Dec 

8, 1976 under 677-313; prepared by Bio/Tox Research Laboratories, Inc. and Experimental 

Pathology Laboratories, Inc., submitted by Diamond Shamrock Agricultural Chemicals, 

Cleveland, Ohio; CDL: 095783-M) 

87283 Diamond Shamrock Chemical Company (19??) Litter Observations in 3-generation Rat 

Reproduction Study--Daconil. (Unpublished study received Aug 11, 1970 under 1F1024; 

CDL:093333-C) 

91288 Paynter, O.E.; Kundzin, M. (1967) Final Report: Three-generation Reproduction Study--Rats: 

Project No. 200-150. (Unpublished study received May 17, 1967 under 7F0599; prepared by 

Hazleton Laboratories, Inc., submitted by Diamond Alkali Co., Cleveland, Ohio; CDL:090769-

K) 

91289 Paynter, O.E.; Kundzin, M. (1967) Final Report: Three-generation Reproduction Study--Rats: 

Project No. 200-155. (Unpublished study received May 17, 1967 under 7F0599; prepared by 

Hazleton Laboratories, Inc., submitted by Diamond Alkali Co., Cleveland, Ohio; CDL:090769-
118 

L) 

112736 Paynter, O. (1965) Progress Report: Three-generation Reproduction Study--Rats: ?Dac-2787|: 

Project No. 200-150. (Unpublished study received Oct 20, 1965 under 7G0516; prepared by 

Hazleton Laboratories, Inc., submitted by Diamond Alkali Co., Cleveland, OH; CDL:090609-H) 

127844 Ford, W.; Killeen, J.; Ignatoski, J.; et al. (1981) A Three Gen- eration Reproduction Study in 

Rats with DS-3701. (Unpub- lished study received Apr 21, 1983 under 677-313; submitted by 

Diamond Shamrock Agricultural Chemicals, Cleveland, OH; CDL: 071524-E) 

127845 Ford, W.; Bush, M.; Killeen, J.; et al. (1982) A One-generation Reproduction Study in Rats with 

DS-3701: Document No. 529-5TX- 81-0193-002. (Unpublished study received Apr 21, 1983 

under 677-313; submitted by Diamond Shamrock Agricultural Chemicals, Cleveland, OH; 

CDL:071525-E) 

131200 Killeen, J.; Ford, W.; Ignatoski, J.; et al. (1981) A Three Genera- tion Reproduction Study in 

Rats with DS-3701: Document No. 107- 5TX-78-0023-002. (Unpublished study received Oct 3, 

1983 under 3F2875; prepared by Diamond Shamrock Agricultural Chemicals, submitted by SDS 

Biotech Corp., Painesville, OH; CDL:071976-A) 

140849 Hastings, T.; Stemmer, K.; Ferrell, J. (1974) 3-Generation Repro- duction Study in Albino Rats 

Using DAC-3701 in the Diet: Project No. 24-051. Final rept. (Unpublished study received Jul 

31, 1974 under 2F1230; prepared by Bio/Tox Research Laboratories, Inc., submitted by 

Diamond Shamrock Chemical Co., Cleveland, OH; CDL:097942-A) 

146938 Ford, W.; Killeen, J.; Ignatoski, J. (1985) Histopathology Evalua- tion--A Three Generation 

Reproduction Study in Rats with SDS- 3701: Report No. 107-5TX-78-0023-102. Unpublished 

study pre- pared by SDS Biotech Corp. 257 p. 

41706201 Lucas, F.; Benz, G. (1990) A Two Generation Reproduction Study in Rats with Technical 

Chlorothalonil: Lab Project Number: 87-0121: 1722-87-0121-TX-003. Unpublished study 

prepared by Ricerca, Inc., and Experimental Pathology Labs, Inc. 1673 p. 

45710209 Myers, D. (1995) Chlorothalonil: A Study of the Effect on Reproductive Function of Two 

Generations in the Rat: Lab Project Number: VCM 21/942505. Unpublished study prepared by 

Huntingdon Research Centre Ltd. 402 p. {OPPTS 870.3800} 

121-1 Phytotoxicity 

MRID Citation Reference 

8144 Bear, W.H. (1973) Lannate L--Celery. (Unpublished study received Mar 5, 1974 under 352-342; 

prepared in cooperation with A. Duda & Sons, submitted by E.I. du Pont de Nemours & Co., 

Wilmington, Del.; CDL:023293-G) 

9563 Kantzes, J.G.; Weaver, L.O. (1964) Results of Tomato Fungicide Tests--1964. (Unpublished 

study received May 29, 1970 under 0F0923; prepared by Univ. of Maryland, Dept. of Botany, 

submit- ted by Uniroyal Chemical, Bethany, Conn.; CDL:091577-Q) 

9943 Smith, D.H.; Crosby, F.D. (1968) Peanuts: Leafspot:~Cercospora~ ?~arachidicola?~. 

(Unpublished study received Feb 26, 1969 un- der 3238-42; prepared by Univ. of Georgia, 

Georgia Station in cooperation with ESSA-Weather Bureau, Georgia Station, submitted by 

Agrico Chemical Co., Tulsa, Okla.; CDL:220181-A) 

13021 Nor-Am Agricultural Products, Incorporated (1963) Nematocides-- Fungicide Trials. 

(Unpublished study received on unknown date under 2139-76; CDL:025254-H) 

22056 Smith, D.H. (1969) 1969 Peanut Leafspot Fungicide Test--Plains, Georgia. (Unpublished study 

including letter dated Oct 24, 1969 from D.H. Smith to Sidney Fox, received Dec 9, 1969 under 

400- EX-37; prepared by Univ. of Georgia, Dept. of Plant Pathology, Georgia Station, submitted 
119 

by Uniroyal Chemical, Bethany, Conn.; CDL:123444-H) 

30230 R.T. Vanderbilt Company, Incorporated (1970) Leaf Spot Test 1--1970 (Miscellaneous 

Chemicals Test). (Unpublished study received May 6, 1971 under 1965-66; CDL:025216-A) 

30715 Simone, ?; Jackson, ?; Couch, ?; et al. (1978) Results from Tersan 1991 & Daconil Alone & in 

Combination on Turfgrass. (Unpub- lished study received Feb 29, 1980 under 352-357; prepared 

in cooperation with Univ. of Illinois and others, submitted by E.I. du Pont de Nemours & Co., 

Wilmington, Del.; CDL:241974-A) 

38737 Green Light Company (1959) A Test of Borer Killer Phytotoxicity to Young Cottonwood Trees: 

Test No. 3. (Unpublished study includ- ing test no. 2, received Jul 29, 1968 under 869-40; CDL: 

236701-A) 

87373 Alvarez, A. (1975) Letter sent to John Hylin dated Oct 17, 1975: Bravo 6F, efficacy and 

phytotoxicity data. (Unpublished study received Mar 15, 1976 under 6E1761; prepared by Univ. 

of Hawaii, Dept. of Plant Pathology, submitted by Interregional Research Project No. 4, New 

Brunswick, NJ; CDL:097359-B) 

97624 Diamond Shamrock Agricultural Chemicals (1976) Results of 1976 Bravo 6F Experimental Use 

Permit on Citrus. (Compilation; un- published study received Sep 14, 1977 under 677-EX-9; 

CDL: 233159-A) 

136952 Diamond Shamrock Agricultural Chemicals (1966) ?Efficacy: DAC2787 and Others|. 

(Compilation; unpublished study received Apr 25, 1967 under 677-282; CDL:004248-A) 

136972 Diamond Shamrock Agricultural Chemicals (1971) ?Efficacy of Bravo 6F|. (Compilation; 

unpublished study received Nov 16, 1971 under 677-313; CDL:004260-B) 

147022 SDS Biotech Corp. (1984) [Bravo 500: Control of Anthracnose on To- matoes]. Unpublished 

compilation. 68 p. 

122-1 Seed Germination/Seedline Emergence and Vegetable Vigor 

MRID Citation Reference 

159006 Kahlon, P.; Banerjee, M. (1979) Evaluation of bravo, phosdrin and telvar as possible 

environmental mutagens. Bull. Environm. Contam. Toxicol. 22:365-370. 

42433808 Backus, P. (1992) Effect of Chlorothalonil on Seed Germination/Seedling Emergence (Tier I): 

Lab Project Number: 92-0119: 5234-92-0119-BE-001. Unpublished study prepared by Ricerca, 

Inc. 63 p. 

42433809 Backus, P. (1992) Effect of Chlorothalonil on Vegetative Vigor of Plants (TIer I): Lab Project 

Number: 92-0120: 5234-92-0120-BE-001. Unpublished study prepared by Ricerca, Inc. 50 p. 

123-2 Aquatic plant growth 

MRID Citation Reference 

42432801 Hughes, J.; Williams, T. (1992) The Toxicity of Technical Chlorothalonil Fungicide to 

Selenaestrum capricornutum: Lab Project Number: B038-001-1. Unpublished study prepared by 

Malcolm Pirnie, Inc. 37 p. 

44908102 Smyth, D.; Magor, S.; Shillabeer, N. (1998) Chlorothalonil: Toxicity to Duckweed: Lab Project 

Number: BL6473/B: AF0336/A: WINO 41417. Unpublished study prepared by Brixham 

Environmental Laboratory, Zeneca Limited. 24 p. 

44908103 Smyth, D.; Magor, S.; Shillabeer, N. (1998) Chlorothalonil: Toxicity to Marine Alga: 

Skeletonema costatum: Lab Project Number: BL6422/B: AF0302/C: WINO 41416. Unpublished 
120 

study prepared by Brixham Environmental Laboratory, Zeneca Limited. 25 p. 

44908104 Smyth, D.; Magor, S.; Shillabeer, N. (1998) Chlorothalonil: Toxicity to Marine Alga: Anabaena 

flos-aquae: Lab Project Number: BL6413/B: AF0302/A: WINO 41414. Unpublished study 

prepared by Brixham Environmental Laboratory, Zeneca Limited. 26 p. 

44908105 Smyth, D.; Magor, S.; Shillabeer, N. (1998) Chlorothalonil: Toxicity to Freshwater Diatom: 

Navicula pelliculosa: Lab Project Number: BL6423/B: AF0302/B: WINO 41415. Unpublished 

study prepared by Brixham Environmental Laboratory, Zeneca Limited. 24 p. 

165-4 Bioaccumulation in fish 

MRID Citation Reference 

45710224 McEwen, A. (1997) Chlorothalonil Bioaccumulation in Rainbow Trout: Lab Project Number: 

VCM 67/963833: VCM/67. Unpublished study prepared by Huntingdon Life Sciences Ltd. 86 p. 

165-5 Bioaccum-aquatic non-target 

MRID Citation Reference 

44286001 Ernst, W.; Doe, K.; Jonah, P. et al. (1991) The toxicity of chlorothalonil to aquatic fauna and the 

impact of its operational use on a pond ecosystem. Archives of Environmental Contamination 

and Toxicology 21:1-9. 

850.1010 Aquatic invertebrate acute toxicity, test, freshwater daphnids 

MRID Citation Reference 

47737324 Gallagher, S.; Kendall, T.; Krueger, H. (2009) Chlorothalonil/Penthiopyrad (DPX-QFA61) SC 

(250 g/L:100 g/L): A 48-Hour Static Acute Toxicity Test with the Cladoceran (Daphnia magna). 

Project Number: DUPONT/25538, DUPONT/25538/OCR, 112A/252. Unpublished study 

prepared by Wildlife International, Ltd. 52 p. 

850.1075 Fish acute toxicity test, freshwater and marine 

MRID Citation Reference 

47737323 Gallagher, S.; Kendall, T.; Krueger, H. (2009) Chlorothalonil/Penthiopyrad (DPX-QFA61) SC 

(250 g/L:100 g/L): A 96-Hour Static Acute Toxicity Test with the Rainbow Trout 

(Oncorhynchus mykiss). Project Number: DUPONT/25536, DUPONT/25536/OCR, 112A/253. 

Unpublished study prepared by Wildlife International, Ltd. 51 p. 

48513701 Brain, R.; Perkins, D.; Bang, J.; et al. (2011) Chlorothalonil Preliminary Response to the 

National Marine Fisheries Service Revised Draft Biological Opinion Concerning Chlorothalonil 

of May 13, 2011: Final Report. Project Number: TK0061921. Unpublished study prepared by 

Syngenta Crop Protection. 25 p. 

850.1950 Field testing for aquatic organisms 

MRID Citation Reference 

46047304 Ashwell, J.; Grant, R.; Dark, R.; et. al. (2002) Outdoor Microcosm Study to Assess the Effect of 

Chlorothalonil on Aquatic Oranisms: Final Report. Project Number: RJ3261B, 00JH010. 

Unpublished study prepared by Syngenta Jealotts Hill International. 923 p. 

850.2100 Avian acute oral toxicity test 

MRID Citation Reference 
121 

46998703 Roy, B. (2006) Acute Oral Toxicity Study of Banko 720 SC in Rats. Project Number: 5138. 

Unpublished study prepared by Jai Research Foundation. 37 p. 

850.3020 Honey bee acute contact toxicity 

MRID Citation Reference 

47737326 Jeyalakshmi, T. (2009) Chlorothalonil/Penthiopyrad (DPX-QFA61) SC (250 g/L:100 g/L): 

Acute Oral and Contact Toxicity to the Honey Bee, Apis mellifera L.. Project Number: 

DUPONT/24930, DUPONT/24930/OCR, 08279. Unpublished study prepared by International 

Institute of Biotechnology and Toxicology . 37 p. 

850.5400 Algal toxicity, Tiers 1 and II 

MRID Citation Reference 

47737325 Porch, J.; Kendall, T.; Krueger, H. (2009) Chlorothalonil/Penthiopyrad (DPX-QFA61) SC (250 

g/L:100 g/L): A 72-Hour Toxicity Test with the Freshwater Alga (Pseudokirchneriella 

subcapitata). Project Number: DUPONT/25534, DUPONT/25534/OCR, 112A/249. Unpublished 

study prepared by Wildlife International, Ltd. 62 p. 

870.1000 Acute toxicity testing--background 

MRID Citation Reference 

46230803 Longobardi, C. (2001) Acute Oral Toxicity Study in the Rat: Nuocide 2002. Project Number: 

8045/005, 8045/005/T/340/2001. Unpublished study prepared by Research Toxicology Centre, 

S.p.A. 67 p. 

46230804 Longobardi, C. (2001) Acute Dermal Toxicity Study in the Rat: Nuocide 2002. Project Number: 

8046/005, 8046/005/T/323/2000. Unpublished study prepared by Research Toxicology Centre, 

S.p.A. 24 p. 

46230806 Longobardi, C. (2001) Acute Eye Irritation in the Rabbit: Nuocide 2002. Project Number: 

8049/005, 8049/005/T/379/2000. Unpublished study prepared by Research Toxicology Centre, 

S.p.A. 24 p. 

46230807 Longobardi, C. (2001) Acute Dermal Irritation Study in the Rabbit: Nuocide 2002. Project 

Number: 8048/005, 8048/005/T/332/2000. Unpublished study prepared by Research Toxicology 

Centre, S.p.A. 23 p. 

46230808 Longobardi, C. (2001) Delayed Dermal Sensitisation Study in the Guinea Pig (Buehler Method): 

Nuocide 2002. Project Number: 8050/005, 8050/005/T/159/2001. Unpublished study prepared 

by Research Toxicology Centre, S.p.A. 26 p. 

47365002 Orr, G. (2008) Bridging Statement Concerning Applicability of Existing of Acute Toxicity 

Studies to Pegasus DFX. Project Number: PEC/007/T. Unpublished study prepared by Rivendell 

Consulting USA, LLC. 6 p. 

870.1100 Acute oral toxicity 

MRID Citation Reference 

45843603 Merkel, D. (2002) Acute Oral Toxicity Study in Rats: Azoxystrobin/Chlorothalonil 660 SC-A: 

Final Report: Lab Project Number: 12496: 1829-02: P320 UDP. Unpublished study prepared by 

Product Safety Labs. 18 p. 

46079703 Merkel, D. (2003) Acute Oral Toxicity Up and Down Procedure in Rats: Propiconazole(CGA64250)/Chlorothalonil SE: Final Report. Project Number: 12966, 1836/02, P320/UDP. 
122 

Unpublished study prepared by Product Safety Labs, Food Products Laboratory and Silliker 

Laboratories of New Jersey, Inc. 16 p. 

46230803 Longobardi, C. (2001) Acute Oral Toxicity Study in the Rat: Nuocide 2002. Project Number: 

8045/005, 8045/005/T/340/2001. Unpublished study prepared by Research Toxicology Centre, 

S.p.A. 67 p. 

46231303 Longobardi, C. (2001) Nuocide 2010: Acute Oral Toxicity Study in the Rat. Project Number: 

8045/006, 8045/006/T/350/2001. Unpublished study prepared by Research Toxicology Centre, 

S.p.A. and Creanova Inc. 65 p. 

46328501 Moore, G. (2004) Acute Oral Toxicity Up And Down Procedure in Rats: NAI-301 4SE. Project 

Number: 15144, P320/UDP. Unpublished study prepared by Product Safety Labs. 15 p. 

46387403 Kuhn, J. (2004) Metalaxyl-M (Mefenoxam)/Chlorothalonil SC (040/400) (A13842C): Acute 

Oral Toxicity Study in Rats: Final Report. Project Number: 8188/04, T006822/04. Unpublished 

study prepared by Stillmeadow, Inc. 13 p. 

46440703 Moore, G. (2004) AND4251: Acute Oral Toxicity Up and Down Procedure in Rats. Project 

Number: 15720, P320/UDP. Unpublished study prepared by Product Safety Labs. 14 p. 

46502803 Merkel, D. (2005) Acute Oral Toxicity Up and Down Procedure in Rats with 

Propiconazole/Fludioxonil/Chlorothalonil SE: Final Report. Project Number: 16351, 

T001009/04, P320/UDP. Unpublished study prepared by Product Safety Laboratories. 17 p. 

46946304 Durando, J. (2006) Acute Oral Toxicity Up and Down Procedure in Rats: CTN G-Pro 720. 

Project Number: 19410, P320/UDP. Unpublished study prepared by Product Safety 

Laboratories. 17 p. 

47061003 Merkel, D. (2004) NOA 446510/Chlorothalonil SC (040/400) (A-13985A): Acute Oral Toxicity 

Up and Down Procedure in Rats: Final Report. Project Number: 14728, T003560/03, P320. 

Unpublished study prepared by Product Safety Laboratories. 17 p. 

47294603 Durando, J. (2007) Disarm C Fungicide: Acute Oral Toxicity Up and Down Procedure in Rats. 

Project Number: 23060, P320/UDP. Unpublished study prepared by Product Safety 

Laboratories. 17 p. 

47333105 Merkel, D. (2004) Acute Oral Toxicity Up and Down Procedure in Rats: LBG-G31FCL. Project 

Number: 14968, P320/UDP. Unpublished study prepared by Product Safety Laboratories. 15 p. 

47405203 Durando, J. (2007) Azoxystrobin/Chlorothalonil SC (038.7/580) (A15935A) - Acute Oral 

Toxicity Up-and-Down Procedure in Rats: Final Report. Project Number: 22325, T008672/06. 

Unpublished study prepared by Product Safety Laboratories. 17 p. 

47409003 Durando, J. (2008) Acute Oral Toxicity Up and Down Procedure in Rats: Chlorothalonil 82.5 

WDG. Project Number: P320/UDP, 24306, 080212/4H. Unpublished study prepared by Product 

Safety Laboratories. 15 p. 

47457903 Moore, G. (2008) Acute Oral Toxicity Up and Down Procedure in Rats: 39.95% Chlorthalonil + 

4.99% Triticonazole SC. Project Number: P320/UDP, 24844, 080411/8D. Unpublished study 

prepared by Eurofins Product Safety Laboratories. 14 p. 

47734803 Kuhn, J. (2009) Antiblu MC-30: Acute Oral Toxicity (UDP) in Rats: Final Report. Project 

Number: 12301/08. Unpublished study prepared by Stillmeadow, Inc. 15 p. 

47737316 Carpenter, C. (2008) Chlorothalonil/Penthiopyrad (DPX-QFA61) SC (250 g/L:100 g/L): Acute 

Oral Toxicity Study in Rats - Up-and-Down Procedure. Project Number: DUPONT/24839, 

DUPONT/24839/OCR, 17747. Unpublished study prepared by E.I. du Pont de Nemours and 

Company. 39 p. 

47900003 Durando, J. (2008) Chlorothalonil/Acibenzolar SC (A16422A)-Acute Oral Toxicity Up-and-
123 

Down Procedure in Rats: Final Report. Project Number: 24535, T008659/06. Unpublished study 

prepared by Eurofins/Product Safety Laboratories. 17 p. 

48326606 Kuhn, J. (2010) Chlorothalonil TC: Acute Oral Toxiciity Study (UDP) in Rats: Final Report. 

Project Number: 14089/10. Unpublished study prepared by Stillmeadow, Inc. 11 p. 

48515005 Clouzeau, J. (1994) Acute Oral Toxicity in Rats: Echo 375/Cymoxanil 50. Project Number: 

11854/TAR. Unpublished study prepared by Centre International de Toxicologie. 29 p. 

 
124 

APPENDIX C: Environmental Fate Studies Kinetic Analyses 

Aerobic Soil Metabolism Kinetic Analysis 

MRID 0040547
125 
126 
127 

 
128 

MRID 47207702
129 
130 

MRID 43879601
131 

MRID 47207703
132 
133 

APPENDIX D: DCI Justification Tables 

Environmental Fate 

Guideline Number: 835.2120 

Study Title: Hydrolysis

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are required for all terrestrial use patterns. 

One study has been submitted that explored the hydrolysis of chlorothalonil at pH 5, 7 and 9 (MRID 0040539). 

The study was originally classified as acceptable; however, after recent review this study has been reclassified 

to supplemental because the portion of the study that was conducted at pH 9 does not meet guideline criteria 

because a material balance and characterization of the transformation products were not provided. The data 

suggest that chlorothalonil may hydrolyze (DT50 = 51 days) under basic conditions (pH >7). Additional data are 

needed on chlorothalonil hydrolysis at pH 9. 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism. Knowledge of the persistence chlorothalonil 

in aquatic environments as well as the identification of transformation products will help the Agency determine 

and estimate exposure of chlorothalonil and other residues of potential toxicological concern to non-target 

organisms. The results of this study will be used in the environmental fate assessment, and later on, in the 

ecological risk characterization. 

For modeling generally the half-life value used in modeling is for pH 7; however, it is likely that the drinking 

water assessment as well as the aquatic exposure assessment will need to be highly refined. Without hydrolysis 

data at pH 9 the effects different aquatic environment (pH >7) may have on chlorothalonil cannot be assessed. 

In addition, drinking water treatment process such as water softening cannot be taken into account. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., assume chlorothalonil is 

stable to hydrolysis at all pH ranges and/or if it transforms it transforms to a residue of toxicological concern). 

This conservative assumption could lead to higher predicted concentrations (EECs or EDWCs), according to the 

models, and consequently, higher risk quotients or drinking water exposures. Also, there would be a higher 

degree of uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.2370 

Study Title: Air Photolysis

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are required for all terrestrial use patterns. 

Based on laboratory data, the vapor pressure (5.7 x 10-7 torr) and Henry’s Law Constant (2.6 x 10-7 atm - 

m3

/mole) values for chlorothalonil indicate some degree of volatility from both soil and water (semi-volatile). 

However, volatilization would not be expected to be a major dissipation route. Nonetheless, a number of 

studies have documented atmospheric transport and redeposition of various pesticides, including chlorothalonil. 

In addition, local ambient air monitoring data from sites near application, as well as locations up to a mile away 

from the application sites. Data from the state of Montana show detections of chlorothalonil in precipitation. 

This indicates that chlorothalonil volatility or particle phase transport plays a role in the dissipation of 

chlorothalonil and that it is possible for chlorothalonil exposure to occur adjacent to application sites, as well as 
134 

areas distant from application sites (long range transport). 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism via the inhalation route. Knowledge of the 

persistence chlorothalonil in air as well as the identification of transformation products will help the Agency 

determine and estimate exposure of chlorothalonil and other residues of potential toxicological concern to nontarget organisms in air. This data will be compared to inhalation toxicity data for non-target organism. 

Specifically, the data will be used to help refine spray drift and volatility estimates of chlorothalonil and its 

transformation of toxicological concern. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., that chlorothalonil does 

not degrade in the air). This conservative assumption could lead to higher predicted concentrations (EECs or 

EDWCs), according to the models, and consequently, higher risk quotients or drinking water exposures. Also, 

there would be a higher degree of uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.2240 

Study Title: Aquatic Photolysis

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are required for all terrestrial use patterns. 

Five aquatic photolysis studies have been submitted for chlorothalonil; however, two of these studies (MRIDs 

40183418 and 0087281) were deemed unacceptable. Another study (MRID 41030001) is not actually an aquatic 

photolysis study. The submitted material provides supplemental information on concerns raised by EPA in the 

review of the unacceptable study, MRID 40183418 including characterization of the artificial light source and 

sample frequency. The submittal of this information does not support changing the classification of MRID 

40183418. A previously classified acceptable study (MRID 0040540) was reevaluated and reclassified as 

supplemental because the study report did not adequately compare the intensity and spectral distribution of the 

artificial light source to natural sunlight or identify transformation products. Based on laboratory data generated 

using an artificial light source, a more recent study (MRID 45710223) showed that chlorothalonil did transform 

under aqueous photolysis with an environmental predicted photo-transformation half-life of 10.3 hours (DT50 = 

10.5 hours; MRID 45710223) at 30 °N latitude. This study was originally classified as acceptable; however, 

after a recent review this study was also reclassified as supplemental. This study was reclassified because three 

major transformation products [47% of the applied radioactivity (AR)] were not identified. Additional data is 

needed to identify these major transformation products or any other potentially toxic transformation products 

observed in the study. 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism. Knowledge of the persistence chlorothalonil 

in aquatic environments as well as the identification of transformation products will help the Agency determine 

and estimate exposure of chlorothalonil and other residues of potential toxicological concern to non-target 

organisms. The results of this study will be used in the environmental fate assessment, and later on, in the 

ecological risk characterization. 

Specifically, the data will be used to derive the aquatic photolysis half-life value used as an input parameter for 

aquatic models—PRZM-EXAMS permitting the Agency estimate exposure of chlorothalonil and its 

transformation products of toxicological concern to non-target organisms. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., the unidentified residues 
135 

are as toxic as chlorothalonil or its most toxic transformation product whichever is greatest). This conservative 

assumption could lead to higher predicted concentrations (EECs or EDWCs), according to the models, and 

consequently, higher risk quotients or drinking water exposures. Also, there would be a higher degree of 

uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.4100 

Study Title: Aerobic Soil Metabolism

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are conditional required for all terrestrial use patterns. 

Six aerobic soil metabolism studies have been submitted for chlorothalonil. Two of the six studies (MRIDs 

87285 and 114035) were determined to be unacceptable because the studies were conducted with bacterial 

cultures (inoculated with soil perfusions) and not soil. The remaining studies have been classified supplemental. 

Taken together these aerobic soil metabolism studies demonstrate that chlorothalonil can undergo a number of 

different chemical reactions in the soil to form a number of different transformation products. All the 

transformation products reported retain the phenyl ring with the exception of CO2. The transformation rate or 

chlorothalonil was also shown to be heavily influenced by the application rate. Higher application rates results 

in long half-life values while lower application rates result in shorter half-life values (MRIDs 43879601, 

47207702, 00087351and 00040547). This is likely the result of a decrease in viability of the soil microbes after 

exposure to chlorothalonil. This is supported by a decrease in observed microbial activity at study termination as 

compared to study initial (MRID 47207703). None of the studies have been conducted at application rates that 

represent the maximum single application rates currently permitted on the label. In general, this suite of studies 

indicate that chlorothalonil degrades over the first 20 days; however, if any chlorothalonil remains after 20-40 

days it is not likely to be metabolized or it is metabolized very slowly. Based on the data presented in this table, 

the half-life value for the currently approved maximum application rate is likely between 18-35 days; however, 

additional data are needed to confirm this assumption. It was also noted that in several of the submitted studies 

that not all of the transformation products were identified. This limits the Agency’s ability to identify residues 

of toxicological concern. 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism. Knowledge of the persistence chlorothalonil 

based on the current use pattern will help the Agency determine and estimate exposure of chlorothalonil and 

other residues of potential toxicological concern to non-target organisms. 

Specifically, the data will be used to derive the aerobic soil metabolism half-life value used as an input 

parameter for aquatic models—PRZM-EXAMS and SCI-GROW/PRZM_GW permitting the Agency estimate 

exposure of chlorothalonil and its transformation products of toxicological concern to non-target organisms. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., that chlorothalonil 

degrades at rates representative of higher applications rates). This conservative assumption could lead to higher 

predicted concentrations (EECs or EDWCs), according to the models, and consequently, higher risk quotients or 

drinking water exposures. Also, there would be a higher degree of uncertainty in the environmental fate 

assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.4300 

Study Title: Aerobic Aquatic Metabolism
136 

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are required for all terrestrial use patterns. 

Three different aerobic aquatic metabolism studies have been submitted for chlorothalonil. All of these studies 

have been classified as supplemental. All three studies indicate that chlorothalonil transformation is rapid >1 

day. Nevertheless, all of these studies have deficiencies that limit the use of the data for risk assessment 

purposes. One common deficiency is that none of the studies identified all the major transformation products. 

One of the studies (MRID 45908001) report fluctuating chlorothalonil concentration (going up and down) and 

thus corresponding half-life values should not be use quantitatively in risk assessment. In another study (MRID 

42226101), artificial sources of water were used and the resulting half-life values may not accurately represent 

those for natural water. Additional data is needed on the transformation rate of chlorothalonil in aerobic aquatic 

systems, as well as full characterization of all major transformation products or transformation products of 

toxicological concern. 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism. Knowledge of the persistence chlorothalonil 

based on the current use pattern will help the Agency determine and estimate exposure of chlorothalonil and 

other residues of potential toxicological concern to non-target organisms. 

Specifically, the data will be used to derive the aerobic aquatic metabolism half-life value used as an input 

parameter for aquatic models—PRZM-EXAMS permitting the Agency estimate exposure of chlorothalonil and 

its transformation products of toxicological concern to non-target organisms. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., the unidentified residues 

are as toxic as chlorothalonil or its most toxic transformation product whichever is greatest). This conservative 

assumption could lead to higher predicted concentrations (EECs or EDWCs), according to the models, and 

consequently, higher risk quotients or drinking water exposures. Also, there would be a higher degree of 

uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.1230/835.1240 

Study Title: Adsorption/ Desorption Batch Equilibrium

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are required for all terrestrial use patterns. 

An adsorption study has been submitted for chlorothalonil; however, it was classified as supplemental because 

the temperature and light conditions used in the experiment were not reported. No data has been submitted on 

the desorption of chlorothalonil from soil. 

Practical Utility of the Data 

How will the data be used? 

Chlorothalonil is toxic to humans and to other non-target organism. Knowledge of the mobility chlorothalonil 

based on the current use pattern will help the Agency determine and estimate exposure of chlorothalonil. 

 

Specifically, the data will be used to determine the fate of chlorothalonil in soil and system systems to better 

characterize the exposure of non-target organisms to chlorothalonil. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., assume highest possible 

concentrations in both water and soil or sediment depending on the exposure scenario evaluated) for risk 
137 

assessment purposes. This conservative assumption could lead to higher predicted concentrations (EECs or 

EDWCs), according to the models, and consequently, higher risk quotients or drinking water exposures. Also, 

there would be a higher degree of uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.4200 

Study Title: Anaerobic Aquatic Metabolism

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are conditional required for all terrestrial use patterns. 

One supplemental anaerobic aquatic metabolism study (MRID 00147975) has been submitted. These data 

suggest that chlorothalonil can transform under anaerobic conditions; however, after reevaluation of the study 

several deficiencies have been noted that limit the use of this data for risk assessment purposes. Redox 

potentials and oxygen concentrations were not provided during the experiment; therefore, it cannot be 

confirmed that the system was anaerobic. Since the test system was purged with nitrogen for 30 days prior to 

study initiation it is assumed that study was conducted under anaerobic conditions; however, additional data are 

needed to confirm this assumption. In addition, no data are provided for day 0. For this reason, chlorothalonil 

concentration at day 0 was assumed to be 100% of the applied radioactivity. The study was also terminated 

before the pattern of formation and decline could be established for the transformation products in one of the 

test systems. The test systems used in this experiment are soil and distilled water. Current guidelines indicate 

that anaerobic aquatic metabolism studies are conducted with sediment (not soil) along with natural water (not 

distilled water). For all the reasons mentioned above, the anaerobic aquatic metabolism study is considered a 

data gap without additional information. 

Practical Utility of the Data 

How will the data be used? 

Specifically, the data will be used to derive the anaerobic aquatic metabolism half-life value used as an input 

parameter for aquatic models—PRZM-EXAMS permitting the Agency estimate exposure of chlorothalonil and 

its transformation products of toxicological concern to non-target organisms. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency would have to make a conservative assumption (e.g., chlorothalonil is stable to 

anaerobic aquatic metabolism). This conservative assumption could lead to higher predicted concentrations 

(EECs or EDWCs), according to the models, and consequently, higher risk quotients or drinking water 

exposures. Also, there would be a higher degree of uncertainty in the environmental fate assessment. 

The lack of this data limits the flexibility the Agency and registrants have to come into compliance with the 

Endangered Species Act. This could result in use restrictions for chlorothalonil that may be unnecessary.

Guideline Number: 835.8100 

Study Title: Field Volatility

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are conditional required for all terrestrial use patterns. 

Based on laboratory data, the vapor pressure (5.7 x 10-7 torr) and Henry’s Law Constant (2.6 x 10-7 atm - 

m3

/mole) values for chlorothalonil indicate some degree of volatility from both soil and water (semi-volatile). 

However, volatilization would not be expected to be a major dissipation route. Nonetheless, a number of 

studies have documented atmospheric transport and redeposition of various pesticides, including chlorothalonil. 

In addition, local ambient air monitoring data from sites near application, as well as locations up to a mile away 

from the application sites. Data from the state of Montana show detections of chlorothalonil in precipitation. 

This indicates that chlorothalonil volatility or particle phase transport plays a role in the dissipation of 
138 

chlorothalonil and that it is possible for chlorothalonil exposure to occur adjacent to application sites, as well as 

areas distant from application sites (long range transport). 

Practical Utility of the Data 

How will the data be used? 

While the Agency does not have a method for assessing long range transport at this time, PERFUM can be used 

to look at vapor phase concentrations of chlorothalonil adjacent to application sites. If a long range transports 

model is available at the time the assessment is completed long range transport of chlorothalonil will be 

assessed. 

How could the data impact the Agency’s future decision-making? 

Without this data the Agency would have to assume exposure to chlorothalonil through volatility. Quantitative 

assessment would be limited; therefore, the risk would be assumed. 

If future endangered species risk assessments are performed without these data, the Agency would have to 

presume risk to non-target organism from use of chlorothalonil in the air. Therefore, use of chlorothalonil and 

its formulated products may need to be restricted in areas where listed species could be exposed. The lack of 

these data will limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act and could result in use restrictions for chlorothalonil that are unnecessarily severe. 

Guideline Number: 835.4300 

Study Title: Terrestrial Field Dissipation

Rationale for Requiring the Data 

According to 40 CFR Part 158, Subpart N (Environmental Fate) §158.1300 (Environmental fate data 

requirements table), these data are conditional required for all terrestrial use patterns. 

Two supplemental terrestrial field dissipation studies are available for chlorothalonil. In both of these studies, 

sampling did not begin until at least one month after chlorothalonil applications. This limits the ability to 

estimate a represent half-life value for chlorothalonil, as well as for any chlorothalonil transformation products. 

The estimate half-life values suggest that substantial amounts of applied chlorothalonil could be available for 

runoff or soil- sorbed erosion transport for several weeks to months post-application (estimated half-life values 

ranged from 33 to 81 days). 

There is also no environmental chemistry method for chlorothalonil in water. 

Practical Utility of the Data 

How will the data be used? 

Terrestrial field dissipation data is used to confirm the conceptual environmental fate model derived from 

laboratory studies to insure that all appropriate dissipation pathways are identified and that all environmentally 

relevant transformation products are identified. 

How could the data impact the Agency’s future decision-making? 

Without these data, the Agency is unable to confirm the conceptual model for the dissipation of chlorothalonil 

and its transformation products in the environment. This lead could lead to a higher degree of uncertainty in the 

environmental fate assessment.

Environmental Effects 

Guideline Number: 850.2100 

Study Title: Avian Acute Oral Toxicity Test 

Rationale for Requiring the Data 

Acceptable acute avian oral toxicity data were submitted for exposures of mallard ducks (Anas platythynchos) to 

chlorothalonil; however, data are not available for a passerine species, which is required under the 40 CFR Part 

158 (Oct. 26, 2007) data requirements for conventional pesticides. The new Part 158 data requirements specify 

that acute avian oral toxicity data be submitted for either mallard duck or bobwhite quail and a passerine species. 

Although, there were no mortalities observed during the acute oral study available for mallard ducks and the LD50

value was determined to be greater than 4,640 mg/kg-bw (the highest concentration tested), the LOAEC in this 
139 

study was determined to be 2,150 mg a.i./kg-bw based on reduced body weight. Weight loss was also noted in the 

available avian sub-acute dietary studies, indicating potential toxicity of chlorothalonil to birds. Therefore, an 

avian oral toxicity test is required for passerine birds, as specified in 40 CFR Part 158. A passerine study protocol 

must be submitted for review by the Agency prior to initiation of this study. 

Practical Utility of the Data 

How will the data be used? 

Acute avian oral toxicity data for passerine species will be used to refine the screening-level assessment by 

determining whether there are differences in avian species sensitivity to chlorothalonil between passerines and 

upland game and waterfowl species. If oral acute toxicity data are not submitted for passerines, risk will be 

assumed for all passerine species. 

How could the data impact the Agency’s future decision-making? 

If future endangered species risk assessments are performed without these data, the Agency would have to assume 

that chlorothalonil “may affect” listed passerine birds directly (and listed species from other taxa indirectly), and 

use of chlorothalonil and its formulated products may need to be restricted in areas where listed species could be 

exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming into 

compliance with the Endangered Species Act and could result in use restrictions for chlorothalonil use that are 

unnecessarily severe. 

Guideline Numbers: 850.4100 and 850.4150 

Study Title: Terrestrial Plant Toxicity Tests (Tier II) 

Rationale for Requiring the Data 

Terrestrial plant toxicity studies using TEP(s) and associated risk analysis of plants are required for registration of 

pesticides with outdoor uses (CFR Part 158). For terrestrial plants, Tier II studies are required when potential 

concerns are triggered (i.e., when there is some indication that there may be significant toxicity to plants). These 

indicators may be an herbicidal mode of action, statements on the label indicating toxicity to plants, or ≥ 25% 

effect levels in the Tier I studies. 

Tier I seedling emergence and vegetative vigor studies are available for chlorothalonil using 16 lb a.i./acre test 

concentrations (MRIDs 42433808 and 42433809). These studies were not conducted with a typical end-use 

product (TEP), but were instead conducted using chlorothalonil mixed with a solvent (100% acetone). When the 

results are compared to the negative (and not the pooled) control, onion shows an inhibition in growth of 26% in 

the seedling emergence study and cucumber shows a 26% inhibition in growth in the vegetative vigor study at the 

16 lb a.i./acre concentration. Because these studies were conducted using TGAI mixed with acetone (instead of a 

TEP) and there were effects greater than 25% noted in the studies for some species, EFED recommends that these 

data be requested for the chlorothalonil risk assessment. If additional toxicity data for terrestrial plants are not 

submitted for chlorothalonil, EFED will assume risk for terrestrial plants. 

Practical Utility of the Data 

How will the data be used? 

Tier II vegetative vigor and seedling emergence data for terrestrial plants will be used to determine the potential 

for chlorothalonil to affect non-target plant species in the terrestrial environment. In the absence of data specific 

for these plants, risk to terrestrial plants will be assumed. 

How could the data impact the Agency’s future decision-making? 

If future endangered species risk assessments are performed without these data, the Agency would have to 

presume risk to non-target terrestrial plants from use of chlorothalonil. Therefore, use of chlorothalonil and its 

formulated products may need to be restricted in areas where listed species could be exposed. The lack of these 

data will limit the flexibility the Agency and registrants have in coming into compliance with the Endangered 

Species Act and could result in use restrictions for chlorothalonil that are unnecessarily severe. 

Guideline Number: Non-guideline 

Study Title: Avian Inhalation Toxicity 

Rationale for Requiring the Data 

Acceptable acute avian toxicity data were submitted for oral exposures of mallard duck (Anas platythynchos) 
140 

to chlorothalonil; however, data are not available for inhalation toxicity. Acute toxicity data using rats 

indicate that mammals are much more sensitive to chlorothalonil when exposed via the inhalation route 

compared to the oral route. Furthermore, an evaluation of inhalation as a route of exposure using the 

Screening Tool for Inhalation Risk (STIR, v. 1.0) model suggests that inhalation exposure is a pathway of 

concern for avian wildlife due to spray drift. Therefore, an acute avian inhalation toxicity test is being 

requested using the most sensitive avian species as shown by avian acute oral studies. The study being 

requested will aid in evaluating this pathway of concern for avian taxa. An avian inhalation study protocol 

must be submitted for review and approval by the Agency prior to initiation of this study. 

Practical Utility of the Data 

How will the data be used? 

Acute avian inhalation toxicity data will be used to identify potential risks to birds from acute exposure to 

chlorothalonil. The data will reduce uncertainties associated with the current risk assessment for birds and 

will improve the Agency’s understanding of the potential effects of chlorothalonil on terrestrial species. If 

inhalation acute toxicity data are not submitted for birds, then risk to birds from acute inhalation exposure to 

chlorothalonil will be presumed. 

How could the data impact the Agency’s future decision-making? 

If future endangered species risk assessments are performed without these data, the Agency would have to 

assume that chlorothalonil “may affect” listed bird species directly (and listed species from other taxa 

indirectly), and use of chlorothalonil and its formulated products may need to be restricted in areas where 

listed species could be exposed. The lack of these data will limit the flexibility of the Agency and the 

registrants for compliance with the Endangered Species Act and could result in use restrictions for 

chlorothalonil use that are unnecessarily severe. 

Guideline Number: 850.1075 

Study Title: Fish Acute Toxicity Test, Estuarine-marine, Chlorothalonil TGAI 

Rationale for Requiring the Data 

An acceptable estuarine-marine fish study for chlorothalonil is not currently available to assess the risk of 

chlorothalonil to estuarine/marine fish on an acute exposure basis. Chlorothalonil is applied in many different 

scenarios where drift or runoff is expected to enter aquatic ecosystems. 

The requested data would allow EPA to refine its acute risk estimates for estuarine/marine fish, and allow it to 

define an action area for endangered species. Risk mitigation strategies (e.g., determining maximum chlorothalonil 

application rate that results in an RQ below the LOC) cannot be evaluated without this data. 

Practical Utility of the Data 

How will the data be used? 

The data will be used to estimate potential risks to estuarine/marine fish, including the likelihood of potential risks 

to endangered species, either by direct effects or by indirect effects, and to reduce uncertainties associated with the 

current ecological risk assessment. By refining the assessment, the Agency will be able to determine whether 

current labeling is appropriate and whether further mitigation is necessary. 

How could the data impact the Agency’s future decision-making? 

If future endangered species risk assessments are performed without these data, the Agency would have to assume 

that chlorothalonil "may affect" endangered fish directly (and endangered species from other taxa indirectly), and 

use of chlorothalonil products might need to be restricted in areas where endangered species could be exposed. The 

lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act and could result in use restrictions for chlorothalonil products which are unnecessarily 

severe.
141 

Guideline Number: 850.1400

Study Title: Fish Early-Life Stage Toxicity (Saltwater), (Cyprinodon variegates) is the preferred species 

Test Substance: Chlorothalonil (TGAI)

Rationale for Requiring the Data

The requested data would allow EPA to refine its chronic risk (growth and reproduction) estimates for 

estuarine/marine fish, and allow it to define an action area for endangered species. Risk mitigation strategies (e.g., 

determining maximum chlorothalonil application rate that results in an RQ below the LOC) cannot be evaluated 

without this data. 

 

Since the registration of chlorothalonil, the Agency has worked to finalize its update to the data requirements in 40 

CFR Part 158. These updated data requirements were promulgated in October 2007. Now one estuarine/marine 

fish early life stage study is required to support all terrestrial, aquatic, forestry, and residential turf use patterns 

when those uses can lead to exposure in estuarine and/or marine habitats. 40 CFR Part 158 was revised to list the 

fish early-life stage and aquatic invertebrate life-cycle studies as separate requirements in the data table; then 

identify each test organism as a freshwater or saltwater species. For the saltwater fish early-life stage and saltwater 

invertebrate life-cycle data requirements, the Agency requires testing of one fish species and one aquatic 

invertebrate species, respectively, for the terrestrial, aquatic, forestry, and residential turf use patterns when 

estuarine or marine habitats may be exposed to the chemical. Previously, the saltwater invertebrate life cycle and 

saltwater fish early life stage tests were combined under one data requirement with testing required of only the 

more sensitive species in acute studies. However, when a pesticide enters the aquatic environment, both groups of 

organisms are exposed. Moreover, acute sensitivity is not necessarily a reliable indicator of chronic sensitivity 

when looking across different groups of organisms. Therefore, chronic data are needed regardless of the results of 

acute testing. 

This change was warranted because the relative sensitivity of fish and invertebrates can vary widely across 

chemicals. Previously, only the more sensitive of the two organisms, either fish or aquatic invertebrates, as 

determined by Tier I acute studies, was tested. However, since both organisms are exposed when a pesticide enters 

an aquatic environment and the acute sensitivity of an invertebrate may not accurately predict the chronic 

sensitivity in fish and vice versa, both species must now be tested for chronic effects. 

Chlorothalonil is toxic to both freshwater and estuarine-marine fish on an acute basis and is toxic to freshwater fish 

on a chronic basis. Therefore, chlorothalonil has the potential to be toxic to estuarine-marine fish on a chronic 

basis as well. Chlorothalonil is applied in many different scenarios where drift or runoff is expected to enter 

estuarine and marine ecosystems. 

Practical Utility of the Data

How will the data be used? 

These data are needed for a registration review decision and for an endangered species assessment, which will be 

conducted as part of that decision. The effects data would be used to determine the likelihood that the chronic risks 

can potentially impact aquatic communities, by direct effects on fish and their reproduction. In the absence of data, 

the Agency will use available toxicity data to determine an acute-to-chronic ratio (ACR) using conservative 

assumptions to be more protective, especially of endangered species. In addition, other sources of data from other 

chemicals in similar chemical class or mode of action group may be used to derive ACR using most conservative 

assumptions. By refining the assessment, the Agency would be able to determine the appropriate mitigation for 

chlorothalonil. 

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without these data, the Agency would have to assume 

that chlorothalonil “may affect” endangered fish directly (and endangered species from other taxa indirectly). 

Thus, use of chlorothalonil might need to be restricted in areas where endangered species could be exposed. The 

lack of these data will limit the flexibility the Agency and registrants have in coming into compliance with the 

Endangered Species Act and could result in use restrictions for chlorothalonil which are unnecessarily severe. 

Guideline Number: 850.1350

Study Title: Mysid Chronic Toxicity 

Test Substance: Chlorothalonil (TGAI)
142 

Rationale for Requiring the Data

The submitted study (MRID 42433807) indicates that chlorothalonil is toxic to estuarine-marine invertebrates on a 

chronic basis; however, the study resulted in a non-definitive NOAEC value (significant effects at all 

concentrations tested). Therefore, a definitive NOAEC value is not available and use of the non-definitive value 

may underestimate risk to estuarine-marine invertebrates. 

The requested data would allow EPA to refine its chronic risk (growth and reproduction) estimates for 

estuarine/marine invertebrates, and allow it to define an action area for endangered species. Risk mitigation 

strategies (e.g., determining maximum chlorothalonil application rate that results in an RQ below the LOC) cannot 

be evaluated without this data. 

 

Practical Utility of the Data

How will the data be used? 

These data are needed for a registration review decision and for an endangered species assessment, which will be 

conducted as part of that decision. The effects data would be used to determine the likelihood that the chronic risks 

can potentially impact aquatic communities, by direct effects on aquatic invertebrates and their reproduction. In 

the absence of data, the Agency may use available freshwater invertebrate toxicity data to determine an acute-tochronic ratio (ACR) using conservative assumptions to be more protective, especially of endangered species. In 

addition, other sources of data from other chemicals in similar chemical class or mode of action group may be used 

to derive ACR using most conservative assumptions. By refining the assessment, the Agency would be able to 

determine the appropriate mitigation for chlorothalonil. 

How could the data impact the Agency’s future decision-making?

If future endangered species risk assessments are performed without these data, the Agency would have to assume 

that chlorothalonil “may affect” endangered estuarine-marine aquatic invertebrates directly (and endangered 

species from other taxa indirectly). Thus, use of chlorothalonil might need to be restricted in areas where 

endangered species could be exposed. The lack of these data will limit the flexibility the Agency and registrants 

have in coming into compliance with the Endangered Species Act and could result in use restrictions for 

chlorothalonil which are unnecessarily severe. 

Guideline Number: 850.1735 and 850.1740 

Study Title: 10-day Whole Sediment Toxicity Test, Chlorothalonil TGAI: 850.1735 with Chironomus tentans

and Hyalella azteca; 850.1740 with Leptocheirus plumulosus 

Rationale for Requiring the Data 

Data for freshwater and estuarine-marine sediment-dwelling invertebrates in a water-sediment test system are not 

currently available to assess the risk of chlorothalonil to freshwater and estuarine/marine sediment-dwelling 

organisms on a short-term exposure basis. Chlorothalonil is applied in many different scenarios where drift or 

runoff is expected to enter aquatic ecosystems. Therefore, 10-day toxicity test following OPPTS 850.1735 and 

850.1740 guidelines are requested for both freshwater organisms, Chironomus tentans and Hyallela azteca as well 

as the recommended estuarine/marine organism, Leptocheirus plumulosus. However, since chlorothalonil may be 

persistent in terrestrial environments, based on the aerobic soil metabolism, and is expected to enter aquatic 

environments through runoff, this runoff may provide a more chronic exposure to sediment organisms. Therefore, it 

is recommended that after the 10-day studies are submitted and reviewed, if there is evidence that chronic toxicity 

testing may be warranted (based on observed toxicity and persistence in the 10-day studies), then chronic testing, 

which would evaluate reproduction as well as survival and growth, should also be requested. 

The requested data would allow EPA to refine its risk estimates for freshwater and estuarine/marine sedimentdwelling invertebrates, and allow it to define an action area for endangered species. Risk mitigation strategies (e.g., 

determining maximum chlorothalonil application rate that results in an RQ below the LOC) cannot be evaluated 

without this data. 

Practical Utility of the Data 

How will the data be used? 

The data will be used to estimate potential risks to freshwater and estuarine/marine sediment-dwelling invertebrates, 
143 

including the likelihood of potential risks to endangered species, either by direct effects or by indirect effects, and to 

reduce uncertainties associated with the current ecological risk assessment. By refining the assessment, the Agency 

will be able to determine whether current labeling is appropriate and whether further mitigation is necessary. 

How could the data impact the Agency’s future decision-making? 

If future endangered species risk assessments are performed without these data, the Agency would have to assume 

that chlorothalonil "may affect" endangered sediment-dwelling invertebrates directly (and endangered species from 

other taxa indirectly), and use of chlorothalonil products might need to be restricted in areas where endangered 

species could be exposed. The lack of these data will limit the flexibility the Agency and registrants have in coming 

into compliance with the Endangered Species Act and could result in use restrictions for chlorothalonil products 

which are unnecessarily severe.

 
144 

APPENDIX E: SIP Input and Output 

Parent Chlorothalonil: 

Degradate SDS-3701: 

Table 1. Inputs 

Table 1. Inputs

Parameter Value

Chemical name Chlorothalonil

Solubility (in water at 25o

C; mg/L) 0.8

Mammalian LD50 (mg/kg-bw) 10000

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Mammalian NOAEL (mg/kg-bw) 92.5

Mammalian test species laboratory rat

Body weight (g) of "other" mammalian species

Avian LD50 (mg/kg-bw) 4640

Avian test species mallard duck

Body weight (g) of "other" avian species

Mineau scaling factor 1.15

Mallard NOAEC (mg/kg-diet)

Bobwhite quail NOAEC (mg/kg-diet) 153

NOAEC (mg/kg-diet) for other bird species

Body weight (g) of other avian species

NOAEC (mg/kg-diet) for 2nd other bird species

Body weight (g) of 2nd other avian species

Table 2. Mammalian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.1376 0.1376

Adjusted toxicity value (mg/kg-bw) 7691.6057 71.1474

Ratio of exposure to toxicity 0.0000 0.0019

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Drinking water exposure 

alone is NOT a potential 

concern for mammals

Table 3. Avian Results

Parameter Acute Chronic

Upper bound exposure (mg/kg-bw) 0.6480 0.6480

Adjusted toxicity value (mg/kg-bw) 2409.2059 16.2636

Ratio of exposure to acute toxicity 0.0003 0.0398

Conclusion*

Drinking water exposure 

alone is NOT a potential 

concern for birds

Drinking water exposure 

alone is NOT a potential 

concern for birds

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

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

may contribute to a total exposure that has potential for effects to non-target animals.
145 

Parameter Value 

Chemical name SDS-3701 

Solubility (in water at 25oC; mg/L) 115.7 

Mammalian LD50 (mg/kg-bw) 242 

Mammalian test species laboratory rat 

Mammalian NOAEL (mg/kg-bw) 6 

Mammalian test species laboratory rat 

Avian LD50 (mg/kg-bw) 158 

Avian test species mallard duck 

Mineau scaling factor 1.15 

Mallard NOAEC (mg/kg-diet) 50 

 

Table 2. Mammalian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 19.9004 19.9004 

Adjusted toxicity value (mg/kg-bw) 186.1369 4.6150 

Ratio of exposure to toxicity 0.1069 4.3121 

Conclusion* 

Exposure through 

drinking water alone is a 

potential concern for 

mammals 

Exposure through 

drinking water alone is a 

potential concern for 

mammals 

 

Table 3. Avian Results 

Parameter Acute Chronic 

Upper bound exposure (mg/kg-bw) 93.7170 93.7170 

Adjusted toxicity value (mg/kg-bw) 82.0376 2.4806 

Ratio of exposure to acute toxicity 1.1424 37.7795 

Conclusion* 

Exposure through 

drinking water alone is a 

potential concern for 

birds 

Exposure through 

drinking water alone is a 

potential concern for 

birds 

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

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

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

 
146 

APPENDIX F: STIR Input and Output 

Input

Application and Chemical Information

Enter Chemical Name Chlorothalonil

Enter Chemical Use Turf (golfcourse)

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

If Spray What Type (enter ground or air) ground

Enter Chemical Molecular Weight (g/mole) 265.91

Enter Chemical Vapor Pressure (mmHg) 5.72E-07

Enter Application Rate (lb a.i./acre) 13

Toxicity Properties

Bird

Enter Lowest Bird Oral LD50 (mg/kg bw) 4640

Enter Mineau Scaling Factor 1.15

Enter Tested Bird Weight (kg) 1.6

Mammal

Enter Lowest Rat Oral LD50 (mg/kg bw) 10000

Enter Lowest Rat Inhalation LC50 (mg/L) 0.012

Duration of Rat Inhalation Study (hrs) 4

Enter Rat Weight (kg) 0.35

Output

Results Avian (0.020 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 8.19E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.03E-03

Adjusted Inhalation LD50 2.23E-02

Ratio of Vapor Dose to Adjusted Inhalation LD50 4.61E-02 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.37E+00

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 6.15E+01 Proceed to Refinements

Results Mammalian (0.015 kg )

Maximum Vapor Concentration in Air at Saturation (mg/m3) 8.19E-03

Maximum 1-hour Vapor Inhalation Dose (mg/kg) 1.29E-03

Adjusted Inhalation LD50 7.14E-01

Ratio of Vapor Dose to Adjusted Inhalation LD50 1.81E-03 Exposure not Likely Significant

Maximum Post-treatment Spray Inhalation Dose (mg/kg) 1.73E+00

Ratio of Droplet Inhalation Dose to Adjusted Inhalation LD50 2.42E+00 Proceed to Refinements

**NOTE**: When entering values, pres

in order to update linked cells.