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Chlorothalonil (CASRN 1897-45-6)

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0143

Chlorothalonil; CASRN 1897-45-6

Health assessment information on a chemical substance is included in IRIS only after a comprehensive review of chronic toxicity data by U.S. EPA health scientists from several Program Offices and the Office of Research and Development. The summaries presented in Sections I and II represent a consensus reached in the review process. Background information and explanations of the methods used to derive the values given in IRIS are provided in the Background Documents.

STATUS OF DATA FOR Chlorothalonil

File First On-Line 03/31/1987

Category (section)
Status
Last Revised
Oral RfD Assessment (I.A.) on-line 03/01/1988
Inhalation RfC Assessment (I.B.) no data
Carcinogenicity Assessment (II.) no data

_I.  Chronic Health Hazard Assessments for Noncarcinogenic Effects

_I.A. Reference Dose for Chronic Oral Exposure (RfD)

Substance Name — Chlorothalonil
CASRN — 1897-45-6
Last Revised — 03/01/1988

The oral Reference Dose (RfD) is based on the assumption that thresholds exist for certain toxic effects such as cellular necrosis. It is expressed in units of mg/kg-day. In general, the RfD is an estimate (with uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population (including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. Please refer to the Background Document for an elaboration of these concepts. RfDs can also be derived for the noncarcinogenic health effects of substances that are also carcinogens. Therefore, it is essential to refer to other sources of information concerning the carcinogenicity of this substance. If the U.S. EPA has evaluated this substance for potential human carcinogenicity, a summary of that evaluation will be contained in Section II of this file.

__I.A.1. Oral RfD Summary

Critical Effect
Experimental Doses*
UF
MF
RfD

Renal tubular
epithelial
vacuolation

2-Year Dog Feeding
Study

Diamond Shamrock
Chemical, 1970a

NOEL: 60 ppm converted
to 1.5 mg/kg/day)

LEL: 120 ppm (converted
to 3 mg/kg/day)
100
1
1.5E-2
mg/kg/day

*Conversion Factors: 1 ppm diet = 0.025 mg/kg/day

__I.A.2. Principal and Supporting Studies (Oral RfD)

Diamond Shamrock Chemical Corporation. 1970a. MRID No. 00057702, 00114034. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Groups of eight male and eight female dogs were fed 0, 60, and 120 ppm chlorothalonil for 2 years. Renal tubular epithelial vacuolation and pigmentation were observed at 120 ppm.

__I.A.3. Uncertainty and Modifying Factors (Oral RfD)

UF — The UF of 100 accounts for uncertainties in the extrapolation from laboratory animals to humans and for sensitive humans.

MF — None

__I.A.4. Additional Studies/Comments (Oral RfD)

Data Considered for Establishing the RfD:

1) 2-Year Feeding - dog: Principal study - see previous description; core grade minimum

2) 13-Week Feeding - rat: NOEL=1.5 mg/kg/day; LEL=3.0 mg/kg/day; (irregular intracytoplasmic inclusion bodies in the proximal convoluted tubule of males); core grade guideline (Diamond Shamrock, 1983a)

3) 2-Year Feeding (oncogenic) - rat: Systemic NOEL=3.0 mg/kg/day (HDT); no core grade (Diamond Shamrock, 1970b)

4) Teratology - rabbit: Maternal NOEL=5 mg/kg/day; Maternal LEL=50\mg/kg/day (4 spontaneous abortions); core grade supplementary (Diamond Shamrock, 1975)

5) Teratology - rat: Maternal NOEL=100 mg/kg/day; Maternal LEL=400\mg/kg/day (mortality, reduced body weight, increased resorptions and post implantation bases); core grade guideline (Diamond Shamrock, 1983b)

6) 3-Generation Reproduction - rat: Reproductive LEL=75 mg/kg/day (LDT) (depressed pup weight, and gastric and esophageal acanthosis in the offspring); no core grade (Diamond Shamrock, 1967)

Data Gap(s): Rabbit Teratology Study; Rat Reproduction Study

__I.A.5. Confidence in the Oral RfD

Study — High
Database — Medium
RfD — Medium

The principal study appears to be of good quality and therefore is given a high confidence rating. The database is supportive, but some of the studies are of low quality. Thus, the database is given medium confidence. Medium confidence in the RfD follows.

__I.A.6. EPA Documentation and Review of the Oral RfD

Pesticide Registration Files

Agency Work Group Review — 04/08/1986

Verification Date — 04/08/1986

__I.A.7. EPA Contacts (Oral RfD)

Please contact the IRIS Hotline for all questions concerning this assessment or IRIS, in general, at (202)566-1676 (phone), (202)566-1749 (FAX) or hotline.iris@epa.gov (internet address).

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_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)

Substance Name — Chlorothalonil
CASRN — 1897-45-6

Not available at this time.

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_II.  Carcinogenicity Assessment for Lifetime Exposure

Substance Name — Chlorothalonil
CASRN — 1897-45-6

Not available at this time.

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_III.  [reserved]
_IV.  [reserved]
_V.  [reserved]

_VI.  Bibliography

Substance Name — Chlorothalonil
CASRN — 1897-45-6
Last Revised — 10/01/1990

_VI.A. Oral RfD References

Diamond Shamrock Agricultural Chemicals. 1967. MRID No. 00038913, 00091288, 00112736. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Diamond Shamrock Chemical Corporation. 1970a. MRID No. 00057702, 00114034. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Diamond Shamrock Chemical Corporation. 1970b. MRID No. 00035559. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Diamond Shamrock Agricultural Chemicals. 1975. MRID No. 00127855. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Diamond Shamrock Agricultural Chemicals. 1983a. MRID No. 00127852. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

Diamond Shamrock Agricultural Chemicals. 1983b. MRID No. 00012963, 00130733. Available from EPA. Write to FOI, EPA, Washington, DC 20460.

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_VI.B. Inhalation RfC References

None

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_VI.C. Carcinogenicity Assessment References

None

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_VII.  Revision History

Substance Name — Chlorothalonil
CASRN — 1897-45-6

Date
Section
Description
03/01/1988 I.A.1. Dose conversion clarified
03/01/1988 I.A.5. Confidence levels revised
09/01/1989 II. Carcinogen assessment now under review
11/01/1989 VI. Bibliography on-line
10/01/1990 III.A. Health Advisory on-line
10/01/1990 VI.D. Health Advisory references added
01/01/1992 IV. Regulatory actions updated
08/01/1995 II. EPA's RfD/RfC and CRAVE workgroups were discontinued in May, 1995. Chemical substance reviews that were not completed by September 1995 were taken out of IRIS review. The IRIS Pilot Program replaced the workgroup functions beginning in September, 1995.
04/01/1997 III., IV., V. Drinking Water Health Advisories, EPA Regulatory Actions, and Supplementary Data were removed from IRIS on or before April 1997. IRIS users were directed to the appropriate EPA Program Offices for this information.
01/12/2000 I.A., II. This chemical is being reassessed under the IRIS Program.
02/09/2004 I.A., II. This chemical is no longer being reassessed under the IRIS Program. See Federal Register February 9, 2004 (Volume 69, Number 26).

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_VIII.  Synonyms

Substance Name — Chlorothalonil
CASRN — 1897-45-6
Last Revised — 03/31/1987

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