2,6-Dimethylphenol (CASRN 576-26-1)
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0230
2,6-Dimethylphenol;
CASRN 576-26-1
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 2,6-Dimethylphenol
File First On-Line 09/01/1988
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 09/07/1988* |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | no data |
*A comprehensive review of toxicological studies was completed 01/06/05 - please see section I.A.6 for more information.
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — 2,6-Dimethylphenol
CASRN — 576-26-1
Last Revised — 09/07/1988
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 |
---|---|---|---|---|
Body weight changes Rat Subchronic Toxicity Veldre and Janes, 1979 |
NOEL: 0.6 mg/kg/day LOAEL: 6.0 mg/kg/day |
1000
|
1
|
6E-4
mg/kg/day |
*Conversion Factors -- None
__I.A.2. Principal and Supporting Studies (Oral RfD)
Veldre, I.A. and H.J. Janes. 1979. Toxicological studies of shale oils, some of their components and commercial products. Environ. Health Perspect. 30: 141-146.
White rats (unspecified number) were administered orally 0, 0.6 and 6.0 mg/kg/day isomeric 2,6-dimethylphenol over an 8-month period. No effects were reported at 0.6 mg/kg/day. Animals receiving 6 mg/kg/day exhibited body weight changes, blood pressure changes, changes in protein sulfhydryl groups in blood serum and internal organs, and histopathological changes in liver, kidney and spleen. Dividing the NOEL of 0.6 mg/kg/day by an uncertainty factor of 1000 results in an oral RfD of 6E-4 mg/kg/day.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — The UF of 1000 includes factors of 10 for species to species extrapolation, 10 to protect sensitive humans and 10 to extrapolate from subchronic to chronic exposure.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
Maazik (1967) reported the results of subchronic oral administration of 2,6- dimethylphenol in rats. No effects were reported at 0.06 mg/kg/day. In the 6.0 mg/kg/day dose group, rats showed decreased weight gain and significant decreased levels of protein sulfhydryl groups in serum. Histological examination showed marked histopathological changes in the liver and kidney.
There are no published data on teratogenicity or reproductive effects.
__I.A.5. Confidence in the Oral RfD
Study — Low
Database — Low
RfD — Low
Confidence in the study is low because details of the experiment are not available. There is one subchronic toxicity study supporting the LOAEL, but there are no other reported long-term assays. Therefore, confidence in the database and RfD are rated low.
__I.A.6. EPA Documentation and Review of the Oral RfD
Source Document — U.S. EPA, 1986
Limited peer review and extensive Agency-wide review, 1986.
Other EPA Documentation — None
Agency Work Group Review — 01/22/1986
Verification Date — 01/22/1986
A comprehensive review of toxicological studies published through 2004 was conducted. No new health effects data were identified that would be directly useful in the revision of the existing RfD for 2,6-Dimethylphenol and a change in the RfD is not warranted at this time. For more information, IRIS users may contact 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 — 2,6-Dimethylphenol
CASRN — 576-26-1
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — 2,6-Dimethylphenol
CASRN — 576-26-1
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 — 2,6-Dimethylphenol
CASRN — 576-26-1
Last Revised — 03/01/1991
_VI.A. Oral RfD References
Maazik, I.K. 1967. Standards for dimethylphenol isomers in water bodies. Gig. Sanit. 11: 28-35.
U.S. EPA. 1986. Health and Environmental Effects Profile for Dimethylphenols. Prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response, Washington, DC.
Veldre, I.A. and H.J. Janes. 1979. Toxicological studies of shale oils, some of their components and commercial products. Environ. Health Perspect. 30: 141-146.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
None
_VII. Revision History
Substance Name — 2,6-Dimethylphenol
CASRN — 576-26-1
Date |
Section |
Description |
---|---|---|
09/07/1988 | I.A. | Oral RfD summary on-line |
03/01/1991 | VI. | Bibliography 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. |
10/28/2003 | I.A.6. | Screening-Level Literature Review Findings message has been added. |
03/03/2005 | I.A.6. | Screening-Level Literature Review Findings message has been removed and replaced by comprehensive literature review conclusions. |
_VIII. Synonyms
Substance Name — 2,6-Dimethylphenol
CASRN — 576-26-1
Last Revised — 09/07/1988
- 576-26-1
- 2,6-Dimethylphenol
- Dimethylphenol, 2,6-
- 2,6-DMP
- 3,4-XYLENOL