Pentabromodiphenyl ether (CASRN 32534-81-9)
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0184
Pentabromodiphenyl ether;
CASRN 32534-81-9
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 Pentabromodiphenyl ether
File First On-Line 03/31/1987
Category (section) |
Status |
Last Revised |
---|---|---|
Oral RfD Assessment (I.A.) | on-line | 08/01/1990 |
Inhalation RfC Assessment (I.B.) | no data | |
Carcinogenicity Assessment (II.) | on-line | 08/01/1990 |
_I. Chronic Health Hazard Assessments for Noncarcinogenic Effects
_I.A. Reference Dose for Chronic Oral Exposure (RfD)
Substance Name — Pentabromodiphenyl ether
CASRN — 32534-81-9
Last Revised — 08/01/1990
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 |
---|---|---|---|---|
Induction of hepatic Subchronic, Rat, Oral Carlson, 1980 |
NOAEL: 3.13 umol/kg/ LOAEL: 6.25 umol/ |
1000
|
1
|
2E-3
mg/kg/day |
*Conversion Factors: 1 umol = 0.5647 mg
__I.A.2. Principal and Supporting Studies (Oral RfD)
Carlson, G.P. 1980. Induction of xenobiotic metabolism in rats by brominated diphenyl ethers administered for 90 days. Toxicol. Lett. 6: 207-212.
Carlson (1980) administered pentabromodiphenyl ether (commercial grade) in corn oil by gavage to groups of six male Sprague-Dawley rats weighing 200 to 250 g for 90 days. Two dosing regimens were used: a high-dose series of 0, 6.25, 12.5, or 25 umol/kg/day (equivalent to 0, 3.53, 7.06, or 14.12 mg/kg/day, respectively) and a low-dose series of 0, 0.78, 1.56, or 3.13 umol/kg/day (equivalent to 0, 0.44, 0.88, or 1.77 mg/kg/day, respectively). Liver enzyme induction occurred at all dose levels, and some of these changes were persistent, lasting for 30-60 days after the cessation of treatment. No histologic liver abnormalities were observed in rats administered the low-dose series. Histologic evaluation was not performed on the high-dose rats; thus, these dose levels should be considered as possible AELs (adverse-effect levels). Since the relevance of hepatic enzyme induction to health effects is not established, this endpoint, in the absence of a histopathology evaluation, is not considered adverse. Thus, the highest NOAEL for pentabromodiphenyl ether is considered to be 1.77 mg/kg/day, the highest dose for which liver enzyme induction occurred, but no histologic liver abnormalities were found.
__I.A.3. Uncertainty and Modifying Factors (Oral RfD)
UF — The uncertainty of 1000 reflects 10 for both intraspecies and interspecies variability to the toxicity of this chemical in lieu of specific data, and 10 for extrapolation of a subchronic effect level to its chronic equivalent.
MF — None
__I.A.4. Additional Studies/Comments (Oral RfD)
None.
__I.A.5. Confidence in the Oral RfD
Study — Low
Database — Low
RfD — Low
Although six dose levels were used in the critical study, the study was of short duration, only one sex and one species were exposed, there were only six animals/group, and few toxic endpoints were examined. The study also did not establish a definitive LOAEL or NOAEL; thus, confidence in the study is low. Supporting evidence is limited; therefore, a low confidence rating is given to the database. Low confidence in the RfD follows.
__I.A.6. EPA Documentation and Review of the Oral RfD
Source Document — U.S. EPA, 1983
This document has received an Agency Review with the help of two external scientists.
Other EPA Documentation — None
Agency Work Group Review — 10/09/1985, 05/15/1986
Verification Date — 05/15/1986
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 Pentabromodiphenyl ether 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 — Pentabromodiphenyl ether
CASRN — 32534-81-9
Not available at this time.
_II. Carcinogenicity Assessment for Lifetime Exposure
Substance Name — Pentabromodiphenyl ether
CASRN — 32534-81-9
Last Revised — 08/01/1990
Section II provides information on three aspects of the carcinogenic assessment for the substance in question; the weight-of-evidence judgment of the likelihood that the substance is a human carcinogen, and quantitative estimates of risk from oral exposure and from inhalation exposure. The quantitative risk estimates are presented in three ways. The slope factor is the result of application of a low-dose extrapolation procedure and is presented as the risk per (mg/kg)/day. The unit risk is the quantitative estimate in terms of either risk per ug/L drinking water or risk per ug/cu.m air breathed. The third form in which risk is presented is a drinking water or air concentration providing cancer risks of 1 in 10,000, 1 in 100,000 or 1 in 1,000,000. The rationale and methods used to develop the carcinogenicity information in IRIS are described in The Risk Assessment Guidelines of 1986 (EPA/600/8-87/045) and in the IRIS Background Document. IRIS summaries developed since the publication of EPA's more recent Proposed Guidelines for Carcinogen Risk Assessment also utilize those Guidelines where indicated (Federal Register 61(79):17960-18011, April 23, 1996). Users are referred to Section I of this IRIS file for information on long-term toxic effects other than carcinogenicity.
_II.A. Evidence for Human Carcinogenicity
__II.A.1. Weight-of-Evidence Characterization
Classification — D; not classifiable as to human carcinogenicity
Basis — No human data and animal data available.
__II.A.2. Human Carcinogenicity Data
None.
__II.A.3. Animal Carcinogenicity Data
None.
__II.A.4. Supporting Data for Carcinogenicity
Pentabromodiphenyl ether (purity unknown) was not mutagenic in a Salmonella typhimurium assay, in which four strains were utilized both with and without metabolic activation (Zeiger et al., 1987).
Pentabromodiphenyl ether is structurally-related to decabromodiphenyl ether, a possible human carcinogen. Decabromodiphenyl ether is also not mutagenic for S. typhimurium.
_II.B. Quantitative Estimate of Carcinogenic Risk from Oral Exposure
None.
_II.C. Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure
None.
_II.D. EPA Documentation, Review, and Contacts (Carcinogenicity Assessment)
__II.D.1. EPA Documentation
Source Document — U.S. EPA, 1984 . Health and Environmental Effects Profile for Brominated Diphenyl Ethers. 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.
The 1984 Health and Environmental Effects Profile for Brominated Diphenyl Ethers has received Agency Review.
__II.D.2. EPA Review (Carcinogenicity Assessment)
Agency Work Group Review — 06/15/1990
Verification Date — 06/15/1990
Screening-Level Literature Review Findings — A screening-level review conducted by an EPA contractor of the more recent toxicology literature pertinent to the cancer assessment for Pentabromodiphenyl ether 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.
__II.D.3. EPA Contacts (Carcinogenicity Assessment)
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).
_III.
[reserved]
_IV. [reserved]
_V. [reserved]
_VI. Bibliography
Substance Name — Pentabromodiphenyl ether
CASRN — 32534-81-9
Last Revised — 08/01/1990
_VI.A. Oral RfD References
Carlson, G.P. 1980. Induction of xenobiotic metabolism in rats by bromi- nated diphenyl ethers administered for 90 days. Toxicol. Lett. 6: 207-212.
U.S. EPA. 1983. Health and Environmental Effects Profile for Brominated Diphenyl Ethers. Prepared by the Office of Health and Environmental Assess- ment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste, Washington, DC.
_VI.B. Inhalation RfC References
None
_VI.C. Carcinogenicity Assessment References
U.S. EPA. 1984. Health and Environmental Effects Profile for Brominated Diphenyl Ethers. 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.
Zeiger, E., B. Anderson, S. Haworth, T. Lawlor, K. Mortelmans and W. Speck. 1987. Salmonella mutagenicity tests: III. Results from the testing of 255 chemicals. Environ. Mutag. 9(Suppl. (9): 1-110.
_VII. Revision History
Substance Name — Pentabromodiphenyl ether
CASRN — 32534-81-9
Date |
Section |
Description |
---|---|---|
09/01/1989 | VI. | Bibliography on-line |
07/01/1990 | II. | Carcinogen assessment now under review |
08/01/1990 | I.A. | Text edited |
08/01/1990 | II. | Carcinogen assessment on-line |
08/01/1990 | VI.C. | Carcinogen references added |
01/01/1992 | I.A.7. | Secondary contact changed |
01/01/1992 | IV. | Regulatory Action section 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., II.D.2. | Screening-Level Literature Review Findings message has been added. |
02/05/2003 | I., II. | This chemical is being reassessed under the IRIS Program. |
12/07/2004 | I.A.2. | Text corrected. |
_VIII. Synonyms
Substance Name — Pentabromodiphenyl ether
CASRN — 32534-81-9
Last Revised — 03/31/1987
- 32534-81-9
- Benzene, 1,1'-oxybis-, pentabromo deriv.
- DE 71
- Pentabromodiphenyl ether