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2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209) (CASRN 1163-19-5)

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2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209); CASRN 1163-19-5

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 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209)

File First On-Line 01/31/1987

Category (section)
Status
Last Revised
Oral RfD Assessment (I.A.) on-line 02/01/1995
Inhalation RfC Assessment (I.B.) no data  
Carcinogenicity Assessment (II.) on-line 01/01/1990

_I.  Chronic Health Hazard Assessments for Noncarcinogenic Effects

_I.A. Reference Dose for Chronic Oral Exposure (RfD)

Substance Name — 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209)
CASRN — 1163-19-5
Last Revised — 02/01/1995

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

No adverse effects
observed

Rat Chronic Oral
Bioassay

Kociba et al., 1975

NOEL: 1.0 mg/kg/day

LOAEL: none

100
1
1E-2
mg/kg/day

Liver enlargement

Rat Subchronic
Oral Bioassay

Norris et al., 1973, 1975

NOEL: 8 mg/kg/day

LOAEL: 80 mg/kg/day

*Conversion Factors: none

__I.A.2. Principal and Supporting Studies (Oral RfD)

Kociba, R.J., L.O. Frauson, C.G. Humiston, et al. 1975. Results of a two- year dietary feeding study with decabromodiphenyl oxide (DBDPO) in rats. J. Combust. Toxicol. 2: 267-285.

Norris, J.M., J.W. Ehrmantraut, C.L. Gibbons, et al. 1973. Toxicological and environmental factors involved in the selection of decadibromophenyl oxide as a fire retardant chemical. Appl. Polym. Symp. 22: 195-219.

Norris, J.M., R.J. Kociba, B.A. Schwetz, et al. 1975. Toxicology of octabromobiphenyl and decabromodiphenyl oxide. Environ. Health Perspect. 11: 153-161.

Kociba et al. (1975) treated Sprague-Dawley (Spartan) rats (25/sex/dose) with daily doses (in the diet) of 0.0, 0.01, 0.1, and 1.0 mg decabromodiphenyl ether (oxide)/kg bw for 2 years. Parameters examined were hematology, clinical chemistry, food consumption, organ weight, body weight, and incidence of histopathologic lesions. No significant differences between treatment and control groups were found. The NOEL for this study was 1.0 mg/kg/day. Norris et al. (1973, 1975) reported on earlier stages of the same study.

Supporting data are reported by Norris et al. (1973, 1975) in a 30-day oral study, in which male rats were administered 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209) at dietary concentrations of 0, 0.01, 0.1, or 1.0%. These concentrations correspond to doses of 0, 8, 80, or 800 mg/kg/day. A NOEL for enlarged livers of 8 mg/kg/day was established. This short-term-to-subchronic NOEL is close to the chronic NOEL of 1.0 mg/kg/day when adjusted by a factor of 10 to account for the uncertainty in extrapolating subchronic dose to chronic dose.

The chemical analysis of the DBDPE used in these studies was reported as follows (Kociba et al., 1975): DBDPE, 77.4%; nonabromodiphenyl ether (NBDPE), 21.8%; and octabromodiphenyl ether (OBDPE), 0.8%. The presence of OBDPE in this mixture has an uncertain effect on the toxicity of DBDPE, since information on the mechanism of toxicity of DBDPE is lacking. An RfD of 0.00062 mg/kg/day has been proposed for OBDPE based on its liver enzyme reducing capabilities (U.S. EPA, 1984). No RfD has been proposed for NBDPE because of lack of data.

__I.A.3. Uncertainty and Modifying Factors (Oral RfD)

UF — The 100-fold factor reflects both the expected intra- and interspecies variability to the toxicity of this chemical in lieu of specific data.

MF — None

__I.A.4. Additional Studies/Comments (Oral RfD)

Absorption and subsequent toxicity of this compound may be highly dependent on the relative proportions of water and oils in the diet because of the chemical's physical properties (low aqueous solubility and varied crystal size).

__I.A.5. Confidence in the Oral RfD

Study — Medium
Database — Low
RfD — Low

The principal study was well-conducted with a sufficient number of animals and toxicity parameters, but lacked an adequate dose range. The supporting in- house study, which established the LOAEL, was very short in duration. Since no other data pertaining to the chronic toxicity of DBDPE were found in the available literature, confidence in the database is rated low. Low confidence in the RfD follows.

__I.A.6. EPA Documentation and Review of the Oral RfD

Source Document — U.S. EPA, 1984

The ADI in the 1984 Health and Environmental Effects Profile has received an Agency Review with the help of two external scientists.

Other EPA Documentation — None

Agency Work Group Review — 10/09/1985

Verification Date — 10/09/1985

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 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209) conducted in August 2003 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).

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_I.B. Reference Concentration for Chronic Inhalation Exposure (RfC)

Substance Name — 2,2',3,3',4,4',5,5',6,6'-Decabromodiphenyl ether (BDE-209)
CASRN — 1163-19-5

Not available at this time.

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_II.  Carcinogenicity Assessment for Lifetime Exposure

Substance Name — Decabromodiphenyl ether (DBDPE)
CASRN — 1163-19-5
Last Revised — 01/01/1990

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 — C; possible human carcinogen

Basis — Based on no human data and limited evidence of carcinogenicity in animals; namely, significantly increased incidences of neoplastic liver nodules in male and female rats and increased incidences of hepatocellular adenomas or carcinomas (combined) in male mice.

__II.A.2. Human Carcinogenicity Data

None.

__II.A.3. Animal Carcinogenicity Data

Limited. Groups of 50 male and 50 female F344-N rats and 50 male and 50 female B6C3F1 mice were given diets containing 0, 25,000, or 50,000 ppm commercial-grade compound (94-97% pure) for 103 weeks. Average daily dosages estimated from food consumption data were 1120 and 2240 mg/kg for low- and high-dose male rats; 1200 and 2550 mg/kg for low- and high-dose female rats; 3200 and 6650 mg/kg for low- and high-dose male mice; and 3760 and 7780 mg/kg for low- and high-dose female mice (NTP, 1985). Rats and mice were maintained without treatment for an additional 1 and 0-1 weeks, respectively, and then sacrificed.

Survival of the low-dose male rats was significantly lower than controls after week 102; however, since no reduced survival was observed in any other group and the decrease was observed so late in the study, the authors concluded that the effect on survival may not have been compound related. The incidences of liver neoplastic nodules in low- and high-dose male rats (7/50 and 15/49, respectively) and high-dose female rats (9/50) were significantly greater than in controls (1/50 in both males and females). Incidences of hepatocellular carcinoma alone (1/50, control males; 1/50, low- dose males; 1/49, high-dose males; 0/50, control females; 2/49, low-dose females; 0/50, high-dose females) were not significantly increased in the treated groups compared to controls. A dose-related trend for mononuclear cell leukemia was observed in treated male rats; however, because of the high incidence in control animals, this was not considered to be biologically significant.

No evidence of carcinogenicity was observed in female mice, although there was some indication that cancer incidence had increased in male mice. Hepatocellular adenomas or carcinomas (combined) occurred at a significantly increased incidence in low-dose male mice (control, 8/50; low dose, 22/50; high dose, 18/50) after correction for survival. The incidence of hepatocellular carcinomas alone was not significant in either the low- or high-dose male mice. Treatment-related effects on body weight or clinical signs of toxicity or survival were not observed in any dose group. A high mortality of control male mice during the first year of the study, presumably due to fighting weakens the evidence of carcinogenicity in male mice. Thyroid gland follicular cell adenomas or carcinomas (combined) also occurred in treated male mice, but the increases were not significant (control, 0/50; low dose, 4/50; high dose, 3/50). The incidence of follicular cell hyperplasia in male mice was significantly increased.

Group of 25 male and 25 female Sprague-Dawley rats were given decabromodiphenyl oxide in the diet at dose levels of 0, 0.01, 0.1, or 1.0 mg/kg/day for 2 years (Kociba et al., 1975; Norris et al., 1973, 1975). The sample used contained 77.4% decabromodiphenyl oxide, 21.8% nonabromodiphenyl oxide and 0.8% octabromodiphenyl oxide. Histological examinations conducted on rats that died during the study and on those sacrificed at termination (day 702 for males and day 735 for females) did not reveal any treatment-related neoplastic effects as indicated by numbers of rats that developed tumors, total numbers of tumors, specific types of tumors or combined male and female data.

__II.A.4. Supporting Data for Carcinogenicity

The commercial-grade compound used in the NTP (1985) carcinogenicity study was not mutagenic in Salmonella typhimurium strains TA1535, TA1537, TA98, or TA100 with or without rat or hamster liver enzyme preparations (NTP, 1985). Doses ranged from 100 to 10,000 /g/plate. Mutagenicity was not detected in the mouse lymphoma L5178Y/TK+/-assay with or without rat liver enzyme preparations at doses of 7 to 10 /g/mL (NTP, 1985). Sister chromatid exchanges or chromosomal aberrations were not induced in Chinese hamster ovary cells treated in vivo at doses of 50 to 500 /g/mL with or without rat liver enzyme preparations (NTP, 1985).

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_II.B. Quantitative Estimate of Carcinogenic Risk from Oral Exposure

Not available.

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_II.C. Quantitative Estimate of Carcinogenic Risk from Inhalation Exposure

Not available.

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_II.D. EPA Documentation, Review, and Contacts (Carcinogenicity Assessment)

__II.D.1. EPA Documentation

Source Document — U.S. EPA, 1987

The 1987 Health and Environmental Effects Profile for Decabromodiphenyl Oxide has received Agency Review.

__II.D.2. EPA Review (Carcinogenicity Assessment)

Agency Work Group Review — 05/04/1989

Verification Date — 05/04/1989

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 Decabromodiphenyl ether (DBDPE) conducted in August 2003 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).

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_III.  [reserved]
_IV.  [reserved]
_V.  [reserved]


_VI.  Bibliography

Substance Name — Decabromodiphenyl ether (DBDPE)
CASRN — 1163-19-5
Last Revised — 12/01/1989

_VI.A. Oral RfD References

Kociba, R.J., L.O. Frauson, C.G. Humiston, et al. 1975. Results of a two-year dietary feeding study with decabromodiphenyl oxide (DBDPO) in rats. J. Combust. Toxicol. 2: 267-285.

Norris, J.M., J.W. Ehrmantraut, C.L. Gibbons, et al. 1973. Toxicological and environmental factors involved in the selection of decadibromophenyl oxide as a fire retardant chemical. Appl. Polym. Symp. 22: 195-219.

Norris, J.M., R.J. Kociba, B.A. Schwetz, et al. 1975. Toxicology of octabromobiphenyl and decabromodiphenyl oxide. Environ. Health Perspect. 11: 153-161.

U.S. EPA. 1984. Health and Environmental Effects Profile for Brominated Biphenyl Ethers. Prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste, Washington, DC.

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_VI.B. Inhalation RfC References

None

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_VI.C. Carcinogenicity Assessment References

Kociba, R.J., L.O. Frauson, C.G. Huniston, et al. 1975. Results of a two- year dietary feeding study with decabromodiphenyl oxide (DBDPO) in rats. J. Combust. Toxicol. 2(4): 267-285.

Norris, J.M., J.W. Ehrmantraut, C.L. Gibbons, et al. 1973. Toxicological and environmental factors involved in the selection of decabromodiphenyl oxide as a fire retardant chemical. App. Polym. Symp. 22: 195-219.

Norris, J.M. R.J. Kociba, B.A. Schwetz, et al. 1975. Toxicology of octabromodiphenyl and decabromodiphenyl oxide. Environ. Health Perspect. 11: 153-161.

NTP (National Toxicology Program). 1985. NTP Technical Report on the Toxicology and Carcinogenesis Studies of Decabromodiphenyl Oxide in F344/N Rats and B6C3F1 Mice (Feed Studies). NTP-TR-309, NIH-85-2565.

U.S. EPA. 1987. Health and Environmental Effects Profile for Decabromodiphenyl Oxide. Prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH, for the Office of Solid Waste, Washington, DC.

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_VII.  Revision History

Substance Name — Decabromodiphenyl ether (DBDPE)
CASRN — 1163-19-5

Date
Section
Description
03/01/1988 I.A.4. Text clarified
03/01/1988 I.A.6. Verification date changed
08/01/1989 II. Carcinogen assessment now under review
08/01/1989 VI. Bibliography on-line
12/01/1989 I.A.2. Corrected Norris et al. 1975 citation
12/01/1989 II. Carcinogen assessment on-line
12/01/1989 VI.C. Carcinogen references added
01/01/1990 II.A.3. Doses corrected
01/01/1992 I.A.7. Secondary contact changed
01/01/1992 IV. Regulatory Action section on-line
02/01/1995 I.A.7. Secondary contact's name changed
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.
02/05/2003 I., II. This chemical is being reassessed under the IRIS Program.
10/28/2003 I.A.6., II.D.2. Screening-Level Literature Review Findings message has been added.

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_VIII.  Synonyms

Substance Name — Decabromodiphenyl ether (DBDPE)
CASRN — 1163-19-5
Last Revised — 01/31/1987

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