Isopropalin (CASRN 33820-53-0)
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0064
Isopropalin;
CASRN 33820-53-0
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 Isopropalin
File First On-Line 01/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 09/01/1990 |
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 — Substance Name — Isopropalin
CASRN — 33820-53-0
Last Revised — 09/01/1990
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 hemoglobin 90-Day Rat Feeding Elanco Products, 1969a |
NOEL: 250 ppm (15 mg/kg/day) LEL: 750 ppm |
1000 |
1 |
1.5E-2 mg/kg/day |
__I.A.2. Principal and Supporting Studies (Oral RfD)
Elanco Products Company. 1969a. MRID No. 00002472. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Male and female rats were divided into 4 groups and fed the following concentrations of isopropalin in their diets: 0, 250 ppm, 750 ppm, and 2250 ppm. Average daily intake was 32, 93, and 288 mg/kg/day at the start and decreased to 15, 48, and 192 mg/kg/day by the end of 90 days. No effects were observed at 250 mg/kg/day. Reduced hemoglobin concentrations, lowered hematocrits, and altered organ weights were observed at the higher doses.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — Based on a subchronic exposure study, an uncertainty factor of 1000 was used to account for inter- and intra-species differences and the insufficient duration of the study to fully assess chronic effects.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
No chronic studies are required for isopropalin because of its use on tobacco. The Agency recognizes that the use of tobacco products is detrimental to the consumer and that the use of this product is voluntary.
Data Considered for Establishing the RfD
1) 90-Day Feeding - rat: Principal study - see discussion above; no core grade)
2) 90-Day Feeding - dog: NOEL=56.25 mg/kg/day (HDT); no core grade (Elanco Products, 1969b)
3) Teratology - rat: Fetotoxic NOEL=123 mg/kg/day; Maternal LEL=123 mg/kg/day (LDT); (soft stool and decreased food consumption); core grade minimum (Elanco Products, 1983a)
4) Teratology - rabbit: Fetotoxic NOEL=270 mg/kg/day; Maternal NOEL=60 mg/kg/day; Maternal LEL=270 mg/kg/day; (decreased food consumption and body weight); core grade minimum (Elanco Products, 1983b)
Data Gap(s): 1) Rat Reproduction Study
__I.A.5. Confidence in the Oral RfD
Study — Medium
Database — Low
RfD — Low
The principal rat studyy establishing the LEL appears to be fairly comprehensive in scope. However, the minimal number of animals used and the lack of detail in general suggest a rating of medium to low. Because of the lack of chronic and reproductive data, confidence in the database is considered low to medium. Confidence in the RfD can also be considered low to medium.
__I.A.6. EPA Documentation and Review of the Oral RfD
Pesticide Registration Standard (1981)
Pesticide Registration Files
Agency Work Group Review — 11/21/1985, 02/05/1986, 05/18/1986, 06/24/1986
Verification Date — 06/24/1986
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 Isopropalin conducted in November 2001 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 — Isopropalin
CASRN — 33820-53-0
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Isopropalin
CASRN — 33820-53-0
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 — Isopropalin
CASRN — 33820-53-0
Last Revised — 09/01/1990
_VI.A. Oral RfD References
Elanco Products Company. 1969a. MRID No. 00002472. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Elanco Products Company. 1969b. MRID No. 00134907. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Elanco Products Company. 1983a. MRID No. 00131230. Available from EPA. Write to FOI, EPA, Washington, DC 20460.
Elanco Products Company. 1983b. MRID No. 00131231. 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 — Isopropalin
CASRN — 33820-53-0
Date |
Section |
Description |
---|---|---|
03/31/1987 | IV. | Regulatory Action section on-line |
06/01/1989 | I.A.6. | Work group review dates added |
09/01/1990 | I.A. | Principal study citation year corrected |
09/01/1990 | I.A.4. | Citations added |
09/01/1990 | VI. | Bibliography on-line |
01/01/1992 | IV. | Regulatory actions updated |
08/01/1995 | I.A.6. | 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. |
12/03/2002 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
_VIII. Synonyms
Substance Name — Isopropalin
CASRN — 33820-53-0
Last Revised — 01/31/1987
- 33820-53-0
- 34113-21-8
- Benzenamine, 4-(1-methylethyl)-2,6-dinitro-N,N-dipropyl-
- Cumidine, 2,6-dinitro-N,N-dipropyl-
- EL 179
- Isopropalin
- 4-Isopropyl-2,6-dinitro-N,N-dipropylaniline
- Paarlan