Bayleton (CASRN 43121-43-3)
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0131
Bayleton;
CASRN 43121-43-3
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 Bayleton
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 — Bayleton
CASRN — 43121-43-3
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
|
---|---|---|---|---|
Decreased body weight 2-Year Rat Dietary Mobay Chemical, 1978 |
NOEL: 50 ppm LEL: 500 ppm |
100
|
1
|
3E-2
mg/kg/day |
*Conversion Factors: 1 ppm = 0.05 mg/kg/day (assumed rat food consumption)
__I.A.2. Principal and Supporting Studies (Oral RfD)
Mobay Chemical Corporation. 1978a. MRID No. 00032538. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Fifty male and 50 female young Wistar rats were fed 50, 500, or 5000 ppm of
Bayleton in the diet for 2 years. A control group was included. Animals were
examined daily for physical appearance, body weight, behavioral changes,
clinical effects, and pharmacological response. A decrease in body weight
gain, erythrocyte count, and hemoglobin level was observed at 500 ppm. At
5000 ppm, cyclic decreases in food consumption accompanied by violent motor
reactions were observed. Decreased body weight gain, increased mortality,
decreased hemoglobin, decreased hematocrit and thrombocyte count, and
increased cholesterol were observed at the high dose.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — An uncertainty factor of 100 has been used to account for the inter- and
intraspecies differences in the extrapolation from laboratory animals to
humans.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Teratogenic studies in rats are positive (cleft palates).
Data Considered for Establishing the RfD:
1) 2-Year Feeding - rat: Principal study - see previous description; core
grade minimum
2) 2-Year Feeding - dog: NOEL=100 ppm (2.5 mg/kg/day); LEL=1000 ppm grade
minimum (25 mg/kg/day) (no weight gain, increased serum alkaline phosphatase
and N-demethylase activity, and increased liver weight); core grade minimum
(Mobay Chemical, 1978b)
3) Teratology - rat: Teratogenic NOEL=50 mg/kg/day; Teratogenic LEL=100
mg/kg/day (cleft palates); Maternal Toxicity NOEL=10 mg/kg/day; Maternal
Toxicity LEL=25 mg/kg/day (increased motor activity and depression of maternal
weight gain); core grade minimum (Mobay Chemical, 1981)
4) Teratology - rabbit: NOEL=50 mg/kg/day (HDT); Maternal Toxicity NOEL=50
mg/kg/day (HDT); core grade minimum (Mobay Chemical, 1976)
5) 3-Generation Reproduction - rat: Fetotoxic NOEL=50 ppm (2.5 mg/kg/day);
LEL=300 ppm (15 mg/kg/day) (decreased pup weight gain); Maternal Toxicity
NOEL=300 ppm; Maternal Toxicity LEL=1800 ppm (90 mg/kg/day) (decreased body
weight gain, effect on lactation performance); Reproductive NOEL=300 ppm;
Reproductive LEL=1800 ppm (decreased fertility, decreased litter size); core
grade minimum (Mobay Chemical, 1979)
Other Data Reviewed:
1) 2-Year Feeding (oncogenic) - mice: Systemic NOEL=50 ppm (7.50 mg/kg/day);
Systemic LEL=300 ppm (45 mg/kg/day) (increased mortality at 12 months); core
grade minimum (Mobay Chemical, 1980)
Data Gap(s): None
__I.A.5. Confidence in the Oral RfD
Study — High
Database — High
RfD — High
The principal study appears to be of good quality, and therefore, is given a high rating. Additional studies are of medium to high quality. Moreover, the 2-year dog study provides the same NOEL and RfD. Therefore, the database is given a high confidence. High confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Office of Pesticide Programs Files
Agency Work Group Review — 03/11/1986
Verification Date — 03/11/1986
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 Bayleton conducted in November 2001 identified one or more significant new studies. IRIS users may request the references for those studies from 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 — Bayleton
CASRN — 43121-43-3
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Bayleton
CASRN — 43121-43-30
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 — Bayleton
CASRN — 43121-43-3
Last Revised — 11/01/1989
_VI.A. Oral RfD References
Mobay Chemical Corporation. 1976. MRID No. 00048631, 00060230. Available
from EPA. Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1978a. MRID No. 00032538. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1978b. MRID No. 00032539. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1979. MRID No. 00032541. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1980. MRID No. 00069013. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
Mobay Chemical Corporation. 1981. MRID No. 00089023. Available from EPA.
Write to FOI, EPA, Washington, DC 20460.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — Bayleton
CASRN — 43121-43-3
Date |
Section |
Description |
---|---|---|
03/01/1988 | I.A.1. | Dose conversion clarified |
03/01/1988 | I.A.4. | Core grades added |
11/01/1989 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory action on-line |
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 — Bayleton
CASRN — 43121-43-3
Last Revised — 03/31/1987
- 43121-43-3
- AMIRAL
- BAY 6681 F
- Bayleton
- BAY-MEB-6447
- 2-BUTANONE, 1-(4-CHLOROPHENOXY)-3,3-DIMETHYL-1-(1,2,4-TRIAZOL-1-YL)-
- 1-(4-CHLOROPHENOXY)-3,3-DIMETHYL-1-(1,2,4-TRIAZOL-1-YL)-BUTAN-2-ONE
- 1-(4-CHLOROPHENOXY)-3,3-DIMETHYL-1-(1H-1,2,4-TRIAZOL-1-YL)-2-BUTANONE
- MEB 6447
- TRIADIMEFON
- 1H-1,2,4-TRIAZOLE, 1-((tert-BUTYLCARBONYL-4-CHLOROPHENOXY)METHYL)-