Carboxin (CASRN 5234-68-4)
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0022
Carboxin;
CASRN 5234-68-4
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 Carboxin
File First On-Line 01/31/1987
Category (section)
|
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 07/01/1989 |
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 — Carboxin
CASRN — 5234-68-4
Last Revised — 07/01/1989
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
|
---|---|---|---|---|
Reduced weight gain, 2-Year Rat Feeding Uniroyal Chemical, |
NOEL: 200 ppm LEL: 600 ppm |
100
|
1
|
1E-1
mg/kg/day |
*Conversion Factors -- l ppm = 0.05 mg/kg/day (assumed rat food consumption)
__I.A.2. Principal and Supporting Studies (Oral RfD)
Uniroyal Chemical. 1969a. MRID No. 00003031, 00021628. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Thirty male and 30 female weanling rats (Charles River Caesarean-derived strain) per group were fed technical D735 (carboxin) at dietary levels of 100 ppm (Group 2), 200 ppm (Group 3), and 600 ppm (Group 4); 60 rats of each sex comprised the control group (Group 1) and received the basal diets only; the diets were available on an ad libitum basis. The observed effects included reduced weight gain and food consumption, increased mortality, and reduced kidney, heart, and spleen weights.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — The UF of 100 includes uncertainties in the extrapolation from laboratory animals to humans.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
The NOEL of the 2-year rat study used for establishing the RfD is supported by the 3-generation rat reproduction study showing the same NOEL.
Data Considered for Establishing the RfD
1) 2-Year Feeding (Oncogenic) - rat: Principal study - see previous description; no core grade
2) 2-Year Feeding - dog: NOEL=600 ppm (15 mg/kg/day) (HDT); no core grade (Uniroyal Chemical, 1969b) 3) 3-Generation Reproduction - rat: NOEL=200 ppm (10 mg/kg/day); LEL=600 ppm (30 mg/kg/day) (depression of pup growth); core grade minimum (Uniroyal Chemical, 1968)
4) Teratology - rat: NOEL=40 mg/kg/day (highest level tested); core grade minimum (Uniroyal Chemical, 1977)
5) Teratology - rabbit: Maternal and Fetotoxic NOEL=375 mg/kg/day; Maternal and Fetotoxic LEL=750 mg/kg/day; Teratogenic NOEL=750 mg/kg/day (HDT); core grade guideline (Uniroyal Chemical, 1981)
Other Data Reviewed:
1) 90-Day Feeding - rat: NOEL=200 ppm (10 mg/kg/day); LEL=600 ppm (30 mg/kg/day) (degeneration of kidneys); no core grade (Uniroyal Chemical, 1966)
Data Gap(s): none
__I.A.5. Confidence in the Oral RfD
Study — Medium
Database — High
RfD — High
The principal study appears to be of adequate quality and is given a medium rating. Additional studies are supportive and the database is complete; thus, the database is given a high rating. High confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Office of Pesticide Programs Files (No Registration Standard for this chemical)
Agency Work Group Review — 03/26/1986
Verification Date — 03/26/1986
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the RfD for Carboxin conducted in September 2002 did not identify any critical new studies. IRIS users who know of important new studies may provide that information to the IRIS Hotline at hotline.iris@epa.gov or (202)566-1676.
__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).
_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)
Substance Name — Carboxin
CASRN — 5234-68-4
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Carboxin
CASRN — 5234-68-4
This substance/agent has not undergone a complete evaluation and determination under US EPA's IRIS program for evidence of human carcinogenic potential.
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Carboxin
CASRN — 5234-68-4
Last Revised — 07/01/1989
_VI.A. Oral RfD References
Uniroyal Chemical. 1966. MRID No. 00003063. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Uniroyal Chemical. 1968. MRID No. 00003032. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Uniroyal Chemical. 1969a. MRID No. 00003031, 00021628. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Uniroyal Chemical. 1969b. MRID No. 00003030, 00021627. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Uniroyal Chemical. 1977. MRID No. 00003120, 00053729. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
Uniroyal Chemical. 1981. MRID No. 00086054. Available from EPA. Write to FOI, EPA, Washington D.C. 20460.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Carboxin
CASRN — 5234-68-4
Date |
Section |
Description |
---|---|---|
03/01/1988 | I.A.5. | Confidence levels revised |
06/30/1988 | I.A.4. | Study descriptions clarified |
07/01/1989 | I.A. | Citations added |
07/01/1989 | I.A. | Reference Citations added |
07/01/1989 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory action updated |
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. |
12/03/2002 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Carboxin
CASRN — 5234-68-4
Last Revised — 01/31/1987
- 5234-68-4
- 5-CARBOXANILIDO-2,3-DIHYDRO-6-METHYL-1,4-OXATHIIN
- Carboxin
- CARBOXINE
- D 735
- DCMO
- 2,3-DIHYDRO-5-CARBOXANILIDO-6-METHYL-1,4-OXATHIIN
- 5,6-DIHYDRO-2-METHYL-3-CARBOXANILIDO-1,4-OXATHIIN
- 5,6-DIHYDRO-2-METHYL-N-PHENYL-1,4-OXATHIIN-3-CARBOXAMIDE
- 2,3-DIHYDRO-6-METHYL-1,4-OXATHIIN-5-CARBOXANILIDE
- 5,6-DIHYDRO-2-METHYL-1,4-OXATHIIN-3-CARBOXANILIDE
- F 735
- FLO PRO V SEED PROTECTANT
- 1,4-OXATHIIN-3-CARBOXAMIDE, 5,6-DIHYDRO-2-METHYL-N-PHENYL-
- 1,4-OXATHIIN-3-CARBOXANILIDE, 5,6-DIHYDRO-2-METHYL-
- 1,4-OXATHIIN, 2,3-DIHYDRO-5-CARBOXANILIDO-6-METHYL-
- VITAVAX