Brominated diphenylethers (EHC 162, 1994)

INTERNATIONAL PROGRAMME ON CHEMICAL SAFETY

ENVIRONMENTAL HEALTH CRITERIA 162

BROMINATED DIPHENYL ETHERS

This report contains the collective views of an international group of
experts and does not necessarily represent the decisions or the stated
policy of the United Nations Environment Programme, the International
Labour Organisation, or the World Health Organization.

First draft prepared by Dr G.J. van Esch, Bilthoven, Netherlands

Published under the joint sponsorship of
the United Nations Environment Programme,
the International Labour Organisation,
and the World Health Organization

World Health Organization
Geneva, 1994

The International Programme on Chemical Safety (IPCS) is a joint
venture of the United Nations Environment Programme, the International
Labour Organisation, and the World Health Organization. The main
objective of the IPCS is to carry out and disseminate evaluations of
the effects of chemicals on human health and the quality of the
environment. Supporting activities include the development of
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that could produce internationally comparable results, and the
development of manpower in the field of toxicology. Other activities
carried out by the IPCS include the development of know-how for coping
with chemical accidents, coordination of laboratory testing and
epidemiological studies, and promotion of research on the mechanisms
of the biological action of chemicals.

WHO Library Cataloguing in Publication Data

Brominated diphenylethers.

(Environmental health criteria; 162)

1.Phenyl ethers -- adverse effects 2.Environmental exposure
3.Occupational exposure I.Series

ISBN 92 4 157162 4 (NLM Classification: QD 341.E7)
ISSN 0250-863X

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CONTENTS

GLOSSARY

BROMINATED DIPHENYL ETHERS -- GENERAL INTRODUCTION

1. GENERAL REMARKS

2. GENERAL INFORMATION ON BROMINATED DIPHENYL ETHERS
2.1. Analytical methods
2.2. Production levels and processes
2.3. Resins, polymers and substrates in which PBDE are used

3. FORMATION OF BROMINATED DIBENZOFURANS DIPHENYL ETHERS
3.1. General
3.2. Additional data on pyrolysis of non-specified PBDE and/or
polymers containing non-specified PBDE

4. WORKPLACE EXPOSURE STUDIES
4.1. Exposure to PBDE
4.2. Exposure to PBDF/PBDD

5. EXPOSURE OF THE GENERAL POPULATION
5.1. General population
5.2. Possible exposure to PBDE and PBDF/PBDD
5.2.1. Television sets
5.2.2. Fire tests and fire accidents

6. ENVIRONMENTAL POLLUTION BY PBDE
6.1. Ultimate fate following use
6.2. Air
6.3. Soil
6.4. Water
6.5. Sediments and sewage sludge
6.6. Aquatic vertebrates
6.7. Aquatic mammals
6.8. Terrestrial vertebrates
6.8.1. Birds
6.8.2. Humans

DECABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS, AND RECOMMENDATIONS
1.1. Summary and evaluation
1.1.1. Identity, physical and chemical properties
1.1.2. Production and uses
1.1.3. Environmental transport, distribution, and
transformation
1.1.4. Environmental levels and human exposure
1.1.5. Kinetics and metabolism in labortory animals and
humans
1.1.6. Effects on laboratory mammals and in vitro test
systems
1.1.7. Effects on humans
1.1.8. Effects on other organisms in the laboratory and
field
1.2. Conclusions
1.2.1. DeBDE
1.2.2. Breakdown products
1.3. Recommendations
1.3.1. General
1.3.2. Further studies

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.1.1. Pure substance
2.1.2. Technical product

2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTALEXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
4.1. Transport and distribution between media
4.1.1. Extraction from polymers
4.2. Biotransformation
4.3. Abiotic degradation
4.3.1. Photodegradation
4.3.2. Pyrolysis
4.3.3. Combustion of DeBDE and polymers containing DeBDE
4.3.3.1 Pyrolysis studies
4.3.3.2 Workplace exposure studies

4.4. Ultimate fate following use
4.4.1. General
4.4.2. Exposure of the general population
4.5. Fire accident
4.6. Simulated fire conditions
4.7. Bioaccumulation

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Air
5.1.2. Water
5.1.3. Aquatic sediments
5.1.4. Aquatic and terrestrial organisms
5.2. Exposure of humans
5.2.1. Occurrence of DeBDE in human tissues
5.2.2. Occupational exposure

6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS
6.1. Absorption and elimination
6.2. Distribution
6.3. Retention and turnover

7. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
7.1. Single exposure
7.1.1. Oral: Rat
7.1.2. Dermal: Rabbit
7.1.3. Inhalation: Rat
7.2. Short-term exposure
7.2.1. Oral
7.2.1.1 Mouse
7.2.1.2 Rat
7.2.2. Inhalation
7.2.2.1 Rat
7.3. Long-term exposure
7.3.1. Oral
7.3.1.1 Mouse
7.3.1.2 Rat
7.4. Skin and eye irritation; sensitization
7.4.1. Skin irritation
7.4.2. Eye irritation
7.4.3. Sensitization
7.4.4. Chloracnegenic activity
7.5. Reproductive toxicity, embryotoxicity, and teratogenicity
7.5.1. Reproductive toxicity
7.5.2. Teratogenicity
7.6. Mutagenicity and related end-points
7.6.1. Mutation
7.6.2. Chromosomal effects
7.7. Carcinogenicity
7.7.1. Oral
7.7.1.1 Mouse
7.7.1.2 Rat

7.8. Other special studies
7.8.1. Liver
7.8.2. Miscellaneous
7.8.3. Toxicity of soot, char, and other waste products
from combustion of DeBDE-containing polymers
7.8.3.1 Acute oral toxicity
7.8.3.2 Skin irritation and comedogenicity
7.8.3.3 Eye irritation

8. EFFECTS ON HUMANS
8.1. General population exposure
8.2. Occupational exposure
8.2.1. Skin sensitization
8.2.2. Neurotoxicity
8.2.3. Epidemiological studies

9. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD

10. PREVIOUS EVALUATIONS BY INTERNATIONAL BODIES

NONABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.2. Recommendations

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

OCTABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.1.1. Identity, physical and chemical properties
1.1.2. Production and uses
1.1.3. Environmental transport, distribution, and
transformation
1.1.4. Environmental levels and human exposure
1.1.5. Kinetics and metabolism in laboratory animals and
humans
1.1.6. Effects on laboratory mammals and in vitro test
systems
1.1.7. Effects on humans
1.1.8. Effects on other organisms in the laboratory and
field
1.2. Conclusions
1.2.1. OBDE
1.2.2. Breakdown products

1.3. Recommendations
1.3.1. General
1.3.2. Further studies

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.1.1. Technical product
2.3. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTALEXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
4.1. Biotransformation
4.2. Abiotic degradation
4.2.1. Pyrolysis of octabromodiphenyl ether
4.2.2. Pyrolysis studies with polymers containing
octabromodiphenyl ether
4.2.3. Behaviour of octabromodiphenyl ether during
processing
4.3. Bioaccumulation
4.4. Ultimate fate following use

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Water
5.1.2. Aquatic sediments
5.1.3. Aquatic and terrestrial organisms
5.2. Exposure of the general population
5.3. Occupational exposure during manufacture, formulation or
use

6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
6.1. Single exposure
6.1.1. Oral: Rat
6.1.2. Dermal: Rabbit
6.1.3. Inhalation: Rat
6.2. Short-term exposure
6.2.1. Oral: Rat
6.2.2. Inhalation: Rat
6.3. Long-term exposure
6.4. Skin and eye irritation; sensitization
6.4.1. Skin irritation
6.4.2. Eye irritation

6.5. Teratogenicity, reproductive toxicity,
and embryotoxicity
6.5.1. Teratogenicity
6.5.1.1 Oral: Rat
6.5.1.2 Oral: Rabbit
6.6. Mutagenicity and related end-points
6.6.1. DNA damage
6.6.2. Mutation
6.6.3. Chromosomal effects
6.7. Carcinogenicity
6.8. Other special studies
6.8.1. Liver
6.9. Appraisal

HEPTABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, AND ANALYTICAL
METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE

6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
6.1. Single exposure
6.2. Skin and eye irritation; sensitization

HEXABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.1.1. Technical product
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.3. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Levels in the environment
5.1.1. Water
5.1.2. Aquatic sediments
5.1.3. Aquatic and terrestrial organisms
5.2. General population exposure

6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

PENTABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.1.1. Identity, physical and chemical properties
1.1.2. Production and uses
1.1.3. Environmental transport, distribution and
transformation
1.1.4. Environmental levels and human exposure
1.1.5. Kinetics and metabolism in laboratory animals and
humans
1.1.6. Effects on laboratory mammals and in vitro test
systems
1.1.7. Effects on humans
1.1.8. Effects on other organisms in the laboratory and
field
1.2. Conclusions
1.2.1. PeBDE
1.2.2. Breakdown products
1.3. Recommendations
1.3.1. General
1.3.2. Further studies

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.1.1. Technical product
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
4.1. Pyrolysis
4.2. Workplace exposure studies
4.3. Bioaccumulation
4.4. Ultimate fate following use

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Levels in the environment
5.1.1. Sediment and sewage sludge
5.1.2. Fish and shellfish
5.1.3. Aquatic mammals
5.1.4. Terrestrial mammals
5.1.5. Birds
5.2. General population

6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

7. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
7.1. Single exposures
7.1.1. Oral
7.1.2. Dermal
7.1.3. Inhalation
7.2. Short-term exposure
7.3. Long-term exposure
7.4. Skin and eye irritation; sensitization
7.4.1. Skin irritation
7.4.2. Eye irritation
7.5. Reproductive toxicity, embryotoxicity and teratogenicity
7.6. Mutagenicity and related end-points
7.7. Carcinogenicity
7.8. Other special studies

TETRABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.1.1. Identity, physical and chemical properties
1.1.2. Production and uses
1.1.3. Environmental transport, distribution, and
transformation
1.1.4. Environmental levels and human exposure
1.1.5. Effects on laboratory mammals and in vitro test
systems
1.1.6. Kinetics and metabolism in laboratory animals and
humans
1.1.7. Effects on humans
1.1.8. Effects on other organisms in the laboratory and
field
1.2. Conclusions
1.2.1. TeBDE
1.2.2. Breakdown products
1.3. Recommendations
1.3.1. General
1.3.2. Further studies

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
4.1. Pyrolysis
4.2. Ultimate fate following use

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Soil and sediment
5.1.2. Fish and shellfish
5.1.3. Birds
5.1.4. Aquatic mammals
5.1.5. Terrestrial mammals
5.2. General population exposure

6. KINETICS AND METABOLISM IN LABORATORY ANIMALS AND HUMANS

TRIBROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.2. Recommendations

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

4. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
4.1. Environmental levels
4.1.1. Birds

DIBROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.2. Recommendations

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Water
5.1.2. Soil/sediment
5.1.3. Birds
5.2. General population exposure

6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
6.1. Single exposure
6.2. Other special studies
6.2.1. Liver

MONOBROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS AND RECOMMENDATIONS
1.1. Summary and evaluation
1.1.1. Physical and chemical properties
1.1.2. Production and uses
1.1.3. Environmental transport, distribution, and
transformation
1.1.4. Environmental levels and human exposure
1.1.5. Kinetics and metabolism in laboratory animals and
humans
1.1.6. Effects on laboratory mammals and in vitro test
systems
1.1.7. Effects on humans
1.1.8. Effects on other organisms in the laboratory and
field
1.2. Conclusions and recommendations

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS
2.1. Identity
2.2. Physical and chemical properties
2.3. Analytical methods

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE
3.1. Natural occurrence
3.2. Anthropogenic sources
3.2.1. Production levels and processes
3.2.2. Uses

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION
4.1. Transport and distribution between media
4.2. Biotransformation
4.2.1. Biodegradation

5. ENVIRONMENTAL LEVELS AND HUMAN EXPOSURE
5.1. Environmental levels
5.1.1. Water
5.1.2. Soil/Sediment
5.1.3. Aquatic organisms

6. EFFECTS ON LABORATORY MAMMALS AND IN VITRO TEST SYSTEMS
6.1. Reproductive toxicity, embryotoxicity,
teratogenicity
6.2. Carcinogenicity

7. EFFECTS ON OTHER ORGANISMS IN THE LABORATORY AND FIELD

REFERENCES

RESUME ET EVALUATION, CONCLUSIONS ET RECOMMANDATIONS

RESUMEN, EVALUACION, CONCLUSIONES Y RECOMENDACIONES

GLOSSARY

PBDE polybrominated diphenyl ethers
MBDE monobromodiphenyl ethers
DiBDE dibromodiphenyl ethers
TrBDE tribromodiphenyl ethers
TeBDE tetrabromodiphenyl ethers
PeBDE pentabromodiphenyl ethers
HxBDE hexabromodiphenyl ethers
HpBDE heptabromodiphenyl ethers
OBDE octabromodiphenyl ethers
NBDE nonabromodiphenyl ethers
DeBDE decabromodiphenyl ethers

PBDF polybrominated dibenzofurans
TeBDF tetrabromodibenzofurans
PeBDF pentabromodibenzofurans
HxBDF hexabromodibenzofurans
HpBDF heptabromodibenzofurans

PBDD polybrominated dibenzodioxins
TeBDD tetrabromodibenzodioxins
PeBDD pentabromodibenzodioxins
HxBDD hexabromodibenzodioxins
HpBDD heptabromodibenzodioxins

PBBz polybrominated benzenes
PBP polybrominated phenols
PBN polybrominated naphthalenes
PBB polybrominated biphenyls
PCB polychlorinated biphenyls
THP Tetrakis(hydroxymethyl)phosphonium salts

ABS acrylonitrile-butadiene-styrene
BASF Badische Anilin und Soda Fabrik
BFRIP Brominated Flame Retardant Industry Panel
BOD biochemical oxygen demand
CEFIC Conseil Européen de l'Industrie Chimique (European
Chemical Industry Council)
DTA differential thermal analysis
EBFRIP European Brominated Flame Retardant Industry Panel
EEC European Economic Community
ER epoxy resin
FY Fiscal Year
GC/ECD gas chromatography/electron capture detector
GC/MS gas chromatography/mass spectrometry
HIPS high impact polystyrene
HPLC high pressure liquid chromatography
HRGC/MS high resolution gas chromatography/mass spectrometry

IG ignition loss
NCI negative chemical ionization
NHATS National Human Adipose Tissue Survey
NIOSH National Institute of Occupational Safety and Health
PA polyamide
PAN polyacrylonitrile
PBT polybutylene terephthalate
PE polyethylene
PET polyethylene terephthalate
PP polypropylene

PR phenolic resin
PS polystyrene
PUR polyurethane
PVC polyvinylchloride
SIM selective ion monitoring
TGA thermal gravimetric analysis
UPE unsaturated (Thermoset) polyesters
US EPA United States Environmental Protection Agency
US NTP United States National Toxicology Program
XPE cross-linked polyethylene

WHO TASK GROUP ON ENVIRONMENTAL HEALTH CRITERIA FOR BROMINATED
DIPHENYL ETHERS

Members

Dr L.A. Albert, Consultores Ambientales Asociados, S.C., Xalapa,
Veracruz, Mexico (Vice-Chairman)

Dr S. Dobson, Institute of Terrestrial Ecology, Monks Wood
Experimental Station, Cambridgeshire, United Kingdom

Professor B. Jansson, Institute of Applied Environmental Research,
Stockholm University, Solna, Sweden

Dr J. Kielhorn, Fraunhofer Institute for Toxicology and Aerosol
Research, Hanover, Germany

Dr M. Luotamo, Finnish Institute of Occupational Health, Helsinki,
Finland

Professor Wai-On Phoon, Worksafe Australia, and University of Sydney,
Sydney, Australia (Chairman)

Mr J. Rea, Department of Environment, London, United Kingdom

Dr S. Sleight, Department of Pathology, Michigan State University,
East Lansing, USA

Observers

Dr M.L. Hardy, Health and Environment, Ethyl Corporation, Baton Rouge,
USA

Dr D.L. McAllister, Quality Assurance and Research Services,

Great Lakes Chemical Corporation, West Lafayette, Indiana, USA

Secretariat

Dr K.W. Jager, International Programme on Chemical Safety, World
Health Organization, Geneva, Switzerland (Secretary)

Dr G.J. van Esch, Bilthoven, The Netherlands (Rapporteur)

NOTE TO READERS OF THE CRITERIA DOCUMENTS

Every effort has been made to present information in the criteria
documents as accurately as possible without unduly delaying their
publication. In the interest of all users of the environmental health
criteria documents, readers are kindly requested to communicate any
errors that may have occurred to the Director of the International
Programme on Chemical Safety, World Health Organization, Geneva,
Switzerland, in order that they may be included in corrigenda, which
will appear in subsequent volumes.

* * *

A detailed data profile and a legal file can be obtained from the
International Register of Potentially Toxic Chemicals, Case Postale
356, 1219 Chatelaine, Geneva, Switzerland (Telephone No. 9799111).

* * *

This publication was made possible by grant number 5 U01
ES02617-14 from the National Institute of Environmental Health
Sciences, National Institutes of Health, USA.

NOTE: The proprietary information contained in this document cannot
replace documentation for registration purposes, because the latter
has to be closely linked to the source, the manufacturing route, and
the purity/impurities of the substance to be registered. The data
should be used in accordance with paragraphs 82-84 and recommendations
paragraph 90 of the Second FAO Government Consultation (1982).

ENVIRONMENTAL HEALTH CRITERIA FOR BROMINATED DIPHENYL ETHERS

A WHO Task Group on Environmental Health Criteria for Brominated
Diphenyl Ethers met at the World Health Organization, Geneva, from
28 June to 2 July 1993. Dr K.W. Jager, of the IPCS, welcomed the
participants on behalf of Dr M. Mercier, Director IPCS, and the three
cooperating organizations (UNEP/ILO/WHO). The Group reviewed and
revised the draft criteria monograph and made an evaluation of the
risks for human health and the environment from exposure to brominated
diphenyl ethers.

The first draft of the monograph was prepared by Dr G.J. van Esch
of the Netherlands, who also prepared the second draft, incorporating
comments received following circulation of the first draft to the IPCS
contact points for Environmental Health Criteria monographs.

Dr K.W. Jager of the IPCS Central Unit was responsible for the
scientific content of the monograph, and Mrs M.O. Head of Oxford,
England, for the editing.

The fact that industry made proprietary toxicological information
available to the IPCS and the Task Group on the products under
discussion is gratefully acknowledged. This allowed the Task Group to
make its evaluation on a more complete data base.

The efforts of all who helped in the preparation and finalization
of the document are gratefully acknowledged.

BROMINATED DIPHENYL ETHERS GENERAL INTRODUCTION

1. GENERAL REMARKS

This Environmental Health Criteria monograph on brominated
diphenyl ethers has been prepared as part of an overview on the impact
of a number of flame retardants on human health and the environment.
The group of polybrominated diphenyl ethers (PBDE) has been selected
as a priority because of the recent interest in these substances. Only
products based on penta-, octa-, and decabromodiphenyl ethers are of
commercial interest.

The general chemical formula of brominated diphenyl ethers is:

Polybrominated diphenyl ethers (PBDE) have a large number of
congeners, depending on the number and position of the bromine atoms
on the two phenyl rings. The total number of possible congeners is
209, and the numbers of isomers for mono-, di-, tri- up to
decabromodiphenyl ethers are: 3, 12, 24, 42, 46, 42, 24, 12, 3, and 1,
respectively.

The commercial PBDE are produced by the bromination of diphenyl
oxide under certain conditions, which result in products containing
mixtures of brominated diphenyl ethers (see the individual PBDE). The
compositions of commercial DeBDE, OBDE, and PeBDE are given in
Table 1.

No, or virtually no, data are available on dibromo-, tribromo-,
hexabromo-, heptabromo-, and nonabromodiphenyl ether (DiBDE, TrBDE,
HxBDE, HpBDE, and NBDE, respectively). Flame retardants containing
predominantly penta-, octa- and decabromodiphenyl ethers are
commercially produced (with tetrabromodiphenyl ether as a major
component of "pentabromo-diphenyl ether", which is a mixture).

The commercial PBDE are rather stable compounds with boiling
points ranging between 310 and 425 °C and with low vapour pressures,
e.g., 3.85 up to 13.3 Pa at 20-25 °C; they are lipophilic substances.
Their solubility in water is very poor, especially that of the higher
brominated diphenyl ethers, and the n-octanol/water partition
coefficients (log Pow) range between 4.28 and 9.9.

Polybrominated diphenyl ethers have not been reported to occur
naturally in the environment, but other types of brominated diphenyl
ethers have been found in marine organisms (Carte & Faulkner, 1981;
Faulkner, 1990).

The presence in the environment of some of the brominated diphenyl
ethers has been documented, the highest concentration being 1 g/kg
sediment in streams or ponds in the vicinity of a manufacturing
facility.

Data on environmental fate, although limited to MBDE, DiBDE, and
DeBDE, suggest that biodegradation is not an important degradation
pathway for the PBDE, but that photodegradation may play a significant
role.

Table 1. Composition of commercial brominated diphenyl ethers

Product Composition

PBDE^a TrBDE TeBDE PeBDE HxBDE HpBDE OBDE NBDE DeBDE

DeBDE 0.3-3% 97-98%
OBDE 10-12% 43-44% 31-35% 9-11% 0-1%
PeBDE 0-1% 24-38% 50-62% 4-8%
TeBDE^b 7.6% -- 41-41.7% 44.4-45% 6-7%

^a Unknown structure.
^b No longer commercially produced. Analysis of one single sample.

Many reports have appeared in the literature describing the
behaviour of brominated flame retardants under pyrolytic conditions.
In general, these reports have indicated that maximum concentrations
of PBDF and/or PBDD were observed at temperatures of 400-800 °C and
that the 2,3,7,8-substituted compounds were seen only in very low
concentrations.

Processing of the polymers under abusive or extreme conditions
produced higher levels of PBDF, but the concentrations were
significantly lower than the values previously reported from
laboratory pyrolysis studies. 2,3,7,8-Brominated isomers were only
found at low levels in a sample abusively processed. The
2,3,7,8-brominated isomers, which are of concern for toxicological and
regulatory reasons, were not detected under normal processing
conditions. The results of the laboratory pyrolysis experiments with
PBDE, showed that PBDF and/or PBDD were formed in various
concentrations, depending on the type of PBDE, the polymer matrix, the
specific processing conditions (temperature, presence of oxygen, etc.)
and equipment used, and the presence of Sb₂O₃. Behaviour of PBDE is
strongly dependent upon the polymer matrix and upon the specific
processing conditions mentioned above, thus laboratory pyrolysis
experiments can hardly be used as reliable models to predict behaviour
in commercial moulding operations.

2. GENERAL INFORMATION ON BROMONATED DIPHENYL ETHERS

2.1 Analytical methods

Several methods to determine residues of PBDE in various media
(air, sewage sludge, sediment, human adipose tissue, marine organisms,
fish, and feed) as well as in commercial products have been reported.
For details, see Table 2.

In general, sample extraction and clean-up techniques for the
analysis of PBDE residues in biological samples are similar to those
developed for PBB (see EHC 152: Polybrominated biphenyls), though
the chromatographic conditions have to be modified in view of the long
retention times of the highly brominated PBDE. Temperature programming
and the use of capillary columns have been found to be very useful for
the separation of the different congeners of PBDE. Recovery for the
different PBDE is generally higher than 80%. Most methods are based on
extraction with organic solvents, such as hexane/acetone,
hexane/diphenyl ether, acetone, etc, purification of the extracts by
gel permeation or adsorption chromatography, and determination mainly
by gas chromatography, either with electron capture detection (ECD),
or, coupled with mass spectrometry (MS). A multi-residue method has
also been developed that includes a multi-step separation enabling the
determination of several polychlorinated and polybrominated pollutants
in biological samples (Jansson et al., 1991).

Table 2. Analytical methods for PBDE

Sample Extraction and clean-up Separation and Limit of Reference
detection determination

Sewage extract with chloroform; evaporate and dissolve GC/MS 0.06 mg/kg Kaart & Kokk
residue in ethanol (1987)

Sediment extract with acetone; clean-up on Florisil NAA; < 5 µg/kg Watanabe et al.
GC/EC < 5 µg/kg (1987b)

Fish extract with acetone-hexane + hexane-ethyl ether; GC/EC; limit of Andersson &
treatment with sulfuric acid or clean-up on alumina; GC/MS detection Blomkvist
chromatography on silica gel 0.1 mg/kg fat (1981)

Animal tissues homogenize; extract with n-hexane-acetone; GC/MS (NCl) 10 ng/kg Jansson et al.
(Multi-residue treatment with sulfuric acid; gel permeation (1991)
method) chromatography; chromatography or silica gel;
chromatography or activated charcoal

Rat liver extract with tetrahydrofuran HPLC Rogers & Hill
(1980)

Table 2 (continued)

Sample Extraction and clean-up Separation and Limit of Reference
detection determination

Fish extract freeze-dried powdered sample with pet. ether; GC/MS < 5 µg/kg fat Kruger (1988)
gel permeation chromatography; clean-up on Florisil; (NCl/SIM)
elute with hexane

Cow's milk centrifuge; gel permeation chromatography; clean-up GC/MS < 2.5 µg/kg fat Kruger (1988)
on Florisil; elute with hexane (NCl/SIM)

Human milk extract with potassium oxalate/ethanol/diethyl GC/MS < 0.6 µg/kg fat Kruger (1988)
ether/pentane; gel permeation chromatography; (NCl/SIM)
clean-up on Florisil; elute with hexane

Human adipose extract with methylene chloride; evaporate; clean-up HRGC/HRMS^a limit of Cramer et al.
tissue on silica gel followed by clean-up on alumina and on detection (1990a,b)
a carbon/silica gel column 0.73-120 ng/kg
(different
congeners)

Commercial PBDE homogenize and dissolve in tetrachloromethane for HPLC; GC/MS; -- deKok et al.
HPLC and GC/MS or n-hexane for TLC/UV TLC/UV (1979)

^a High resolution gas chromatography/high resolution mass spectrometry.

2.2 Production levels and processes

According to the information given by the European Brominated
Flame Retardant Industry Panel (EBFRIP), eight manufacturers are
currently producing polybrominated diphenyl ethers. They are: Dead Sea
Bromines/Eurobrome (The Netherlands); Atochem (France); Ethyl
Corporation (USA); Great Lakes Chemical Corporation (USA); Tosoh
(Japan); Matsunaga (Japan); Nippo (Japan); Great Lakes Chemical Ltd
(United Kingdom).

The annual global consumption of PBDE is 40 000 tonnes (30 000
tonnes of DeBDE; 6000 tonnes OBDE and 4000 tonnes PeBDE) (Arias,
1992).

It has been reported that the use of brominated flame retardants
in Japan increased from 2500 tonnes in 1975 to 22 100 tonnes in 1987
(Watanabe & Tatsukawa, 1990).

The production and import figures for the European Economic
Community (EEC) are given in Table 3.

Table 3. Production and import quantities of PBDE in metric
tonnes in the EEC^a

1986 1987 1988 1989

Production 4276 3624 4066 3843
Import 4310 3492 4955 7103
Total 8586 7116 9021 10 946

^aFrom: EBFRIP (1990).

Data on the usage of PBDE are available for some individual
European countries. Germany uses 3000-5000 tonnes/year, Sweden
1400-2000 tonnes/year, and The Netherlands 3300-3700 tonnes/year
(OECD, 1991; van Zorge, 1992), but Pijnenburg & Everts (1991) and
Pijnenburg et al. (1992) reported a level of 2500 tonnes PBDE for the
last country. In the United Kingdom, up to 2000 tonnes per year are
used (UK DOE, 1993).

Because of the significant reduction in the fire hazard for the
public achieved by the use of PBDE in a wide range of applications,
particularly in the furniture industry, and electrical/computer
components and housing, the consumption of PBDE has significantly
increased over the last years (EBFRIP, 1990).

2.3 Resins, polymers, and substrates in which PBDE are used

The major uses of the polybrominated diphenyl ethers in descending
order of importance are: high-impact polystyrene, ABS, flexible
polyurethane foam, textile coatings (not clothing), wire and cable
insulation, electrical/electronic connectors and other interior parts.
These applications account for at least 80-90% of the consumption of
brominated diphenyl ethers in the USA.

Brominated diphenyl ethers are used as additive flame retardants.
Additive flame retardants are incorporated into the plastic matrix
like other additives, such as plasticizers. The ideal additive is
inexpensive, colourless, easily blended, compatible, heat and light
stable, efficient, permanent, and has no deleterious effect on the
properties of the base polymer. The most important limitations are
incompatibilities that affect the physical properties of the polymers
and the tendency for additives to be fugitive. These additive flame
retardants are much more prone to leaching or escape from the finished
polymer product than the reactive flame retardants (Hutzinger et al.,
1976; Hutzinger & Thoma, 1987; Larsen, 1980).

The uses of penta-, octa-, and decabromodiphenyl ethers in the
different resins, polymers, and substrates are shown in Table 4. The
principal applications of these PBDE-containing substances are shown
in Table 5.

PBDE are used in the different resins, polymers, and substrates at
levels ranging from 5 up to 30%. The quantities used for each
application are not publicly available. In consumer products, resins
containing PBDE are typically used in interior parts, minimizing the
potential for exposure of the public. The incorporation of the PBDE
into the polymer matrix further reduces the possibilities of exposure
(EBFRIP, 1990).

Table 4. Use of penta- (PeBDE), octa- (OBDE), and decabromodiphenyl ethers
(DeBDE) in resins, polymers, and substrates^a

Resins/polymers/substrates DeBDE OBDE PeBDE

ABS X
Epoxy-resins X
Phenolic resins X X
PAN X
PA X X
PBT X X
PE/XPE X
PET X
PP X
PS, HIPS X X
PVC X X
PUR X
UPE X X
Rubber X X
Paints/lacquers X X
Textiles X X

^aFrom: EBFRIP (1990); UK Department of Environment (1992).

Table 5. The various applications of resins in which PBDE are used are listed below^a

Polymer Principal applications Examples of final products

ABS Moulded parts TV-sets/business machines,
computer housings, household
appliances (hairdryer, curler),
automotive parts, electronics,
telecommunications

EPOXY Circuit boards, Computers, ship interiors,
protective coatings electronic parts

PAINTS/ Coatings Marine and industry lacquers
LACQUERS for protection of containers

PHENOLICS Printed circuit boards Paper laminates/glass prepregs
for printed circuit boards

PAN Panels, electrical Lighting panels for elevators
components and rooms, housing of electrical
appliances

PA Electrical connectors, Computers, connectors,
automative interior housing in electrical industry,
parts board, electrical connectors,
automotive industry,
transportation

PBT Electrical connectors Switches, fuse, switch box,
and components computer housings, switchboard
electrical connectors,
stereos, business machines,
military electronics

PE/XPE Cross-linked wire and Major application: power cable
cable, foam tubing, with cross-linked low density
weather protection PE; also used for conduit for
and moisture barriers building with high density PE;
Final uses: portable apparatus
building control, instrument,
shipboard, automotive, marine
appliances, insulation of heating
tubes

PET Electrical Boxes, relays, coils, bobbins
components

Table 5. (cont'd).

Polymer Principal applications Examples of final products

PP Conduits, electronic TV and electronic devices, such
devices as yoke, housings, circuit board
hangers, conduits; Final uses:
electro-mechanical parts TV,
hot waste water pipes,
underground junction boxes

PS, HIPS TV cabinets and back TV back panels, computer
covers, electrical covers and housings of
appliance housings electrical appliances, office
machines, smoke detectors

PVC Cable sheets Wire end cables, floor mats,
industrial sheets

PUR Cushioning materials, Furniture, sound insulation
packaging, padding panels, wood imitations,
transportation

RUBBER Transportation Conveyor belts, foamed pipes
for insulation

TEXTILES Coatings Back coatings, impregnation:
carpets, automotive seating,
furniture in homes and official
buildings, aircraft, undergrounds,
tents, trains, and military
safety clothing

UPE Circuit boards, Electrical equipment, coatings
coatings for chemical processing plants
mouldings, military and marine
applications: construction
panels

^aFrom: EBFRIP (1990).

3. FORMATION OF BROMINATED DIBENZOFURANS AND DIBENZODIOXINS FROM
POLYBROMINATED DIPHENYL ETHERS

3.1 General

Polybrominated dibenzofurans (PBDF) and polybrominated
dibenzodioxins (PBDD) can be formed from polybrominated diphenyl
ethers, polybrominated phenols, and polybrominated biphenyls under
different conditions, including heating (combustion). Laboratory
experiments have also demonstrated the formation of PBDF and PBDD
during the pyrolysis of certain other brominated flame retardants (see
the EHC on Brominated flame retardants, in preparation). As
discussed in EHC 88: Polychlorinated dibenzo-para-dioxins and
dibenzofurans, there are hundreds of possible congeners of
halogenated dibenzofurans and dibenzo-dioxins. However, only congeners
with substituents in the 2,3,7,8-positions are of toxicological
significance. In many reports, only the total levels of PBDF and PBDD
are given, without regard to substitution pattern; such totals are of
limited value in the estimation of possible risk.

Hutzinger & co-workers investigated the pyrolysis of brominated
flame retardants and flame retardant polymer systems and several
publications have appeared. In general, the results reported showed
that brominated dibenzofurans were observed at 700-800 °C and that the
2,3,7,8-substituted compounds were seen in only low concentrations, if
at all (Thoma et al., 1987a,b; Thoma & Hutzinger, 1987; Dumler et al.,
1989).

Shortly after the initial reports of Buser and Hutzinger, BFRIP
and German chemical companies (Bayer, BASF, and Hoechst) and American
industries independently reported the results of combustion and
pyrolysis experiments with flame retarded polymers (BFRIP, 1990).

Recently, brominated aromatic compounds have also attracted
attention, since reports have appeared about emissions of PBDD and
PBDF and other brominated and mixed halogenated aromatic compounds in
accidental fires and from the combustion of waste (see section 4 of
both DeBDE and OBDE).

For more information on these pyrolysis experiments, see the
different sections relating to the individual brominated diphenyl
ethers, e.g., PeBDE, OBDE, and DeBDE.

As an example, the formation of PBDF and PBDD from
decabromodiphenyl ether is illustrated in Fig. 1.

3.2 Additional data on the pyrolysis of non-specified PBDE and/or
polymers containing non-specified PBDE

The earliest published work on the pyrolysis of brominated flame
retardants was that of Buser, whose first paper appeared in 1986
(Buser, 1986). Buser pyrolysed three technical PBDE mixtures with
different degrees of bromination from commercial sources (pentabromo-,
71% bromine; octabromo-, 79% bromine (predominantly hexa- to
nonabrominated PBDE) and decabromo-, 83% bromine, 97% DeBDE) at
510-630 °C in small quartz vials. The vials were placed in a heated
oven for about one minute, and the contents analysed.

A range of PBDD and PBDF was found with a total yield of up to 10%.
HRGG/MS analysis revealed the formation of reasonably simple mixtures
of reaction products with often one or two main PBDF- and
PBDD-isomers. Debromination reactions lead to lower brominated PBDF
and PBDD congeners. In general, the higher brominated PBDE lead to
higher brominated PBDF and PBDD. Most likely, the PBDF and PBDD are
formed in intramolecular cyclization reactions involving the attack by
oxygen on the diphenyl ether system (Fig. 1) (Buser, 1986; Bieniek et
al., 1989).

The next report to appear in the literature was also in 1986 from
the laboratory of Hutzinger. Hutzinger's group pyrolysed penta- and
decabromodiphenyl ethers at 700, 800, and 900 °C, in a quartz tube
oven, for about 10 min. They did not provide any isomer-specific
results, but they reported the formation of PBDF and PBDD. Hutzinger
continued to investigate the pyrolysis of brominated flame retardants
and brominated flame retardant polymer systems, and several
publications appeared (Thoma et al., 1987a,b; Thoma & Hutzinger, 1987;
Dumler et al., 1989a). In general, the results reported in these
publications were consistent with those of earlier work in that
maximum concentrations of PBDF were observed at 700-800 °C and
2,3,7,8-substituted compounds were seen only in very low
concentrations, if at all.

Shortly after the initial reports of Buser and Hutzinger, BFRIP
and German chemical companies (Bayer, BASF and Hoechst) independently
reported the results of combustion and pyrolysis experiments with
flame retarded polymers.

In the German work, pyrolysis studies were conducted with
high-impact polystyrene/DeBDE, polypropylene/DeBDE, and ABS/OBDE
(Neupert et al., 1989) (see also individual flame retardants). In all
of these studies, the pyrolysis residues were analysed for the
presence of PBDD and PBDF. While brominated PBDF were identified, only
very small quantities of 2,3,7,8-TeBDF were observed (see Table 6)
(BFRIP, 1990).

Table 6. Analytical results from the pyrolysis products of ABS/OBDE
(Bayer)^a

Compound Concentration

Test 1 (ppm) Test 2 (ppm)

Brominated ND^b ND^b
dibenzodioxins

Brominated
dibenzofurans:

MBDF 115 60
DiBDF 10 000 7500
TrBDF 8000 2500
TeBDF 2000 2500
2,3,7,8-TeBDF < 0.1 < 8
PeBDF 1700 2000
HxBDF 530 470
HpBDF < 1.4 32
OBDF < 3 < 2.5

^aFrom: BFRIP(1990).
^bND = Not detectable.

Other brominated pyrolysis products of PBDE may be formed by
cleavage and oxidation, including PBBz, phenol, and some naphthalenes.
PBDF, however, may also be formed from small reactive species
generated during PBDE cleavage (Umweltbundesamt, 1989; Buser, 1986)
(see also the individual brominated diphenyl ethers).

Striebich et al. (1991) examined gas phase oxidative and pyrolysis
thermal decomposition of a 1:1 percentage weight mixture of two
commercial polybrominated diphenyl ether products (tri- through
deca-bromination). The gas phase material was quantitatively
transported to a quartz thermal reactor and subjected to a series of
controlled time/temperature exposures (300-800 °C for 2.0 seconds) in
either air or a nitrogen atmosphere. Thermal decomposition products
were identified. Isomers with higher levels of bromination were
generally more stable than lower brominated diphenyl ethers, under
both oxidative and pyrolytic conditions. Table 7 shows the approximate
yields of products from brominated diphenyl ethers. At 800 °C, all
products were decomposed to HBr or non-detectable products, in both
air and nitrogen. Neither PBDF/PBDD nor any parent material could be
detected at this temperature.

Table 7. Thermal decomposition products from a mixture of two
commercial PBDE (1:1 w/w)^a

Product Maximum yield (%)

Nitrogen (650 °C) Air (625 °C)

Dibromobenzenes 0.35 ND^c
Tribromobenzenes 0.64 0.92
Tetrabromobenzenes 0.43 0.95
Unknown (pentabromobenzenes?) 0.04 0.24
Brominated alkanes, alkenes, 1.40 0.77
and other PICs^b

DiBDF 0.03 ND^c
TrDBF 0.03 0.03
TeBDF 0.03 0.03
DiBDD ND^c 0.04
TrBDD ND^c 0.04
TeBDD ND^c 0.01

^aFrom: Striebich et al. (1991).
^bPICs = Products of incomplete combustion.
^cND = Not detectable.

4. WORKPLACE EXPOSURE STUDIES

4.1 Exposure to PBDE

Inhalation exposure to brominated diphenyl ethers is expected to
be low, since the vapour pressure of these chemicals is in the range
of 10^-7 mmHg. Particulates in the respirable range are expected to be
formed during the grinding of solids. As inhalation of dust is
possible, the use of dust respirators and gloves/goggles is
recommended in areas of potential exposure.

Dermal exposure may occur during filtration, drying,
drumming/bagging, size reduction, and maintenance (US EPA, 1986).

Exposure to these compounds can also take place during processing
(incorporation into various polymers) and the use of the polymer blend
to fabricate the final articles. After processing, the resin is
generally in the form of pellets rather than powder. Exposure is
expected to be low at fabrication sites because of the low vapour
pressure and of ventilation controls (US EPA, 1986).

4.2 Exposure to PBDF/PBDD

Workers may be exposed to PBDF/PBDD during the production and
processing of plastics containing PBDE as flame retardants and of
products made from them. In addition, workers and the general
population may be exposed to PBDF/PBDD when products, particularly
from the electrical, electronic, and computer industries, emit
PBDF/PBDD during normal operations (see section 4 of both DeBDE and
OBDE).

The PBDF/PBDD contents of component parts taken from 6 electrical
appliances (including printers, TV sets, and computer terminals) as
well as two casings were determined. PBDF/PBDD were detected in 16 of
the materials; mainly higher brominated PBDF at concentrations of
between 0.007 and 4.2 mg/kg (sum of MBDF to HxBDF/MBDD to HxBDD) were
found (Hamm & Theisen. 1992).

Determination of PBDE and PBDF concentrations in air and dust
samples were made in offices having a large number of TV or computer
monitors in operation: the police traffic control office in Hamburg
(47 monitors; room 100 m², 6 m high, 23 °C) and three rooms of a
television company with monitors (20 °C).

In the police traffic control office, air samples were taken for 3
days at a level of 1.5 m above the floor, a total of 84 m³ air being
drawn, and analysed. Dust samples were taken from the monitors from a
total surface of 3 × 10 m (39 g).

In the first room of a television company (50 m²), where 58
monitors were in use, a total of 129 m³ air was taken over 5 days. In
the second room (40 m²),where 38 monitors were in use, 126 m³ air
was taken, while in the third room (30 m²), where 42 monitors were in
use, 145 m³ air was taken. Dust samples were also collected once a
day from all rooms using a vacuum cleaner.

The concentrations in air of the police station and the television
company ranged between 0.29 and 1.27 pg PBDF/m³ and 97 pg PBDE/m³.
Indoor dust contained PBDF at low ppb and PBDE at high ppb levels.
2,3,7,8-substituted PBDF were not detected (limit of determination
between 0.3 and 0.1 µg/m³) (Ball et al., 1992).

5. EXPOSURE OF THE GENERAL POPULATION

5.1 General population

Limited information is available on the exposure of the general
population to brominated diphenyl ethers. Uptake of TeBDE and PeBDE
may occur in humans via the foodchain, e.g., by consuming fish. In
Germany, PBDE has been detected in human and cow's milk at levels of
2.6 and 3 µg/kg fat, respectively (Kruger, 1988).

Remmers et al. (1990) found evidence of the occurrence of
polychlorinated diphenyl ethers (PCDE) and PBDE in human adipose
tissue specimens from the USA, during the analysis of these tissues
for dioxins and furans. The results showed the presence of HxBDE/HxCDE
through to DeBDE/DeCDE in the tissues analysed.

The presence of brominated diphenyl ethers was indicated in all of
the 47 samples analysed (Cramer et al., 1990a,b). The human samples
were composites derived from all parts of the USA and covering ages
ranging from birth to > 45 years. Additional work is needed to
confirm the presence of these compounds, which have been found
provisionally in the following frequencies and concentrations; HxBDE
(72%; nd-1000 ng/kg); HpBDE (100%; 1-2000 ng/kg) and OBDE (60%;
nd-8000 ng/kg). DeBDE was found in only a few samples at
concentrations of 0.4-0.7 ng/kg.

Exposure may also mainly occur through skin contact (flame retardants
in polymers used in textiles), but also via inhalation (release of
flame retardants from the polymer matrix) (US EPA, 1986).

5.2 Possible exposure to PBDE and PBDF/PBDD

5.2.1 Television sets

Studies were carried out to determine whether PBDF escape from TV
sets. Four air samples (2 parallel to each other) were taken over 3
days in a closed room (volume 26.8 m³), where a new TV set was
operating for 17 h/day. The surface temperature of the TV set (back
panel) was 38-40 °C. One sampling was performed above the TV set,
while the others were carried out in the centre of the room (2.2 m
from the TV set). The levels in the centre of the room of tri-,
tetra-, penta-, and hexabromo-dibenzofurans were 25, 2.7, 0.5, and
0.1 µg/m³, respectively (levels in outdoor air ranged from < 0.05 to
0.16 µg/m³). Above the TV set, the concentrations of the 4 PBDF were
143, 11, 0.5, and < 0.1 µg/m³. Hepta- and octabromodibenzofuran, and
poly-brominated dibenzodioxins were not found (limits of determination
0.1 and 0.2 µg/m³, respectively) (Bruckmann et al., 1990).

An investigation was conducted to determine the emissions of PBDE
and PBDF from plastics in two TV sets, one colour and one monochrome,
two computer monitors, and three printers, under conditions of use.
Analytical methods were refined to obtain a reliable determination of
PBDF. Each appliance was placed, under conditions of use, in a test
chamber. The volume of the steel chamber was 1.17 m³ (1.5 × 1.07 ×
0.82m). For three days, pure air was continuously drawn through the
chambers at a rate of 1.5 m³/h; the emitted compounds were absorbed

on a sampler for the subsequent extraction and determination of PBDE
and PBDF with 4 or more bromines. PBDF concentrations were found to
vary between not detected (limit of detection 3-10 pg) and 1799 pg per
appliance tested and PBDE concentrations, between 0.4 and
889 ng/appliance; 2,3,7,8 isomers (1070 µg/appliance) were detected
only from the colour TV set (Ball et al., 1991).

Three new television sets were placed in a 1.81 m³ test chamber.
Two of the cabinets were made from polystyrene, which was flame
retarded with 11.5% DeBDE. The third television set was made of
high-impact polystyrene, treated with DeBDE/Sb₂O₃ as a flame
retardant. PBDF and PBDD concentrations were determined in air
collected over 3 days while the two television sets were operating and
during one day when the third TV set was operating. The concentrations
of TeBDD, PeBDD, TeBDF, and PeBDF ranged between 0.09 and 1.52 µg/m³
(Ranken et al., 1990).

5.2.2 Fire tests and fire accidents

Six appliances and 2 casings were burned in a fire test room
(floor area 21 m², volume 48 m³), which was kept closed during the
fire tests and slowly ventilated after extinguishing the fires (worst
case conditions). After the fire test, samples of combustion residues
and smoke condensate were taken. Smoke was collected in 5 tests. The
combustion residues showed the presence of PBDF and PBDD in
concentrations ranging between 1 and 1930 mg/kg and from the casing
components almost 1%. Smoke condensate from contaminated surfaces
contained levels of between 6 and 1610 µg monobromo- up to
hexabromodibenzofuran/dibenzodioxin per m². Smoke contained
11-1700 µg monobromo- up to hexabromo- dibenzofuran/dibenzodioxin per
m³ (see Table 8) (Hamm & Theisen, 1992).

Residues and smoke condensates resulting from actual fire
accidents with 9 TV sets were examined. PBDF/PBDD concentrations in
the residues were mainly in the µg/kg range, one value being
107 mg/kg. Close to the fire site, the PBDF/PBDD area contamination
concentrations were between 0.1 and 13.1 µg/m³ (see Table 9) (Hamm &
Theisen, 1992).

It was concluded that the levels of PBDF/PBDD produced in real
fires are much lower than those produced under fire-test conditions.

Table 8. PBDF/D concentrations in original components of electrical appliances and in samples from fire tests with these
appliances or with their casings^a

Object of investigation Original components Fire test samples

Casings Printed circuit Combustion Smoke Smoke
boards residues condensate

Total mono- to Total mono- to Total mono- to Total mono- to Total mono-to
hexaBDF/D µg/g hexaBDF/D µg/g hexaBDF/D hexaBDF/D hexaBDF/D
(ppm) (ppm) µg/g (ppm) µg/m² µg/m³

Casing of electrical appliance 1 0.63 -^b 8700 177 -^b
Casing of electrical appliance 2 0.64 -^b 7750 1610 -^b
Electrical appliance 3 -^c 1.77 468 106 456
Electrical appliance 4 0.06 3.44 43 260 355
Electrical appliance 5 0.81 1.98 18 396 1700
Electrical appliance 6 4.20 0.35 1930 234 1350
Etectrlcal appliance 7 -^c 0.13 1 6 11
Electrical appliance 8 1.26 0.007 24 323 -^b

^aFrom: Hamm & Thiesen (1992).
^b = Not determined.
^c = Not detectable.

Table 9. PBDF/D-concentrations in residues and smoke condensates from
real fire accidents with television sets^a

Fire accident Combustion Smoke condensates
(Case number) residues

Close to fire site At some
distance from
fire site

Total mono- to Total mono- to Total mono- to
hexaBDF/D hexaBDF/D hexaBDF/D
µg/g (ppm) µg/m² µg/m²

I 0.235 10.7 0.665
II 0.004 0.134 0.102
III 0.209 13.1 0.382
IV 0.009 ND^b ND^b
V 0.001 4.82 1.39
VI 0.017 0.759 0.425
VII 0.001 0.021 0.008
VIII 0.001 10.5 5.37
IX 107 7.47 0.847

^aFrom: Hamm & Thiesen (1992).
^bND = Not detectable.

6. ENVIRONMENTAL POLLUTION BY PBDE

6.1 Ultimate fate following use

Products containing PBDE are disposed of in the normal domestic
waste stream (landfill and incineration).

No studies are available on the fate of PBDE-containing products
in landfills, but there is concern that the PBDE may eventually leach
out. Bearing in mind that PBDE, at least the congeners with more than
3 bromine atoms, are persistent in the environment, the introduction
of such chemicals into widespread products may be a considerable
long-term diffuse source of emissions of these compounds to the
environment. This type of source is difficult to control and the
unnecessary use of persistent organic compounds should be avoided.

Formation of PBDF and/or PBDD as a result of landfill fires is
also a possibility, though no data are available on the scale of this
source. The results of pyrolysis experiments showed that PBDE can form
PBDF and PBDD (in much smaller quantities) under a wide range of
heating conditions (see General Introduction sections 3.1 and 3.2). If
chlorine is present, mixed halogenated furans/dioxins can also be
generated (Oberg et al., 1987; Zier et al., 1991). Unless sufficiently
high temperatures and long residence times are maintained, PBDF/PBDD
can be generated during the incineration of products containing PBDE.
They can also result from poorly-controlled combustion gas cooling.
Modern, properly operated municipal waste incineration (MWI) should
not emit significant quantities of PBDF/PBDD, regardless of the
composition of the municipal waste.

Lahl et al. (1991) reported increases in dibenzofuran and
dibenzodioxin levels in filter dust, when products containing PBDE
were added to the feed-stock. Riggs et al. (1990) reported PBDF
generation when a flame retarded resin was burnt under simulated MWI
conditions. However, Oberg et al. (1987) reported no increased
emissions of dibenzodioxins when the bromine content of an
incineration feed-stock was increased. Monobromodichloro-dibenzofuran
levels were slightly increased. Oberg & Bergström (1990) conducted
further experiments with a hazardous waste incinerator, to study the
relationship between bromine levels in municipal waste and incinerator
dibenzodioxin and dibenzofuran emissions. They concluded that no
unacceptable environmental risks were associated with the incineration
of brominated compounds in plants with good combustion conditions
equipped with efficient flue gas cleaning. They further noted that
only 0.0125% of the feed to Swedish MWIs was brominated waste.

6.2 Air

Watanabe et al. (1992) reported on the presence of PBDE in the air
in Taiwan and Japan. The concentrations in the air samples collected
in Taiwan from a recycling plant in January 1991 were, in general,
higher than those in Japan; 3 samples were analysed in Taiwan, and 5
in Japan. Tribromo-, tetrabromo-, pentabromo-, and hexabromodiphenyl
ethers were present in the following mean concentrations: Taiwan, 32,
52, 23, and 31 µg/m³, and, Japan, 7.1, 21, 8.9, and 21 µg/m³,
respectively.

6.3 Soil

Two ash and two soil samples were collected in Taiwan from a
recycling plant in January 1991 and analysed for the presence of PBDE.
Tri-, tetra-, penta-, hexa-, and decabromodiphenyl ethers were present
in ash in the following concentrations 20-20, 130, 78-110, 47-54, and
510-2500 µg/kg, respectively; the concentrations in soil were 38-40,
75-104, 41-84, 20-23 and 260-330 µg/kg, respectively. Hepta- and
octabromodiphenyl ether were not found (Watanabe et al., undated).

6.4 Water

Marine, estuarine, and river water samples were analysed for the
presence of the different PBDE. Except for monobromo-diphenyl ether,
levels of all the higher brominated PBDE were below the detection
limit. MBDE was mainly found in the surroundings of manufacturing
plants in the USA (US EPA, 1986).

6.5 Sediments and sewage sludge

In Japan, Spain, Sweden, and the USA, studies were carried out to
determine the presence of the different PBDE in marine, estuarine, or
river sediment. PBDE were mainly found in river sediment. In general,
the levels were below 100 µg/kg dry weight, except in rivers in the
vicinity of manufacturing plants. In these cases, the concentrations
were much higher. In a river in Sweden, concentrations of 11.5 mg
DeBDE, 0.8 mg TeBDE, and 2.8 mg PeBDE/kg dry weight were found. In the
USA, at a manufacturing plant, as much as 1 g DeBDE/kg was found
(Zweidinger et al., 1978; DeCarlo, 1979; Environment Agency Japan,
1983, 1989, 1991; Watanabe et al., 1986, 1987b; Fernandez et al.,
1992).

The upper layers in a laminated sediment core from the Baltic Sea
(Bornholm Deep) contained higher levels of TeBDE and PeBDE than the
deeper layers, indicating an increasing burden of these compounds
(Nylund et al., 1992).

A series of samples of sewage sludges from municipal waste water
treatment plants in Germany were analysed for poly-halogenated
compounds, such as halogenated diphenyl ethers. Tribromo- to
heptabromodiphenyl ethers were found at relatively high concentrations
(Hagenmaier et al., 1991). Sewage sludge was analysed in Sweden for
the presence of TeBDE and PeBDE. Concentrations of 15 and 19 µg/kg,
respectively, were found (Sellström et al., 1990a,b).

6.6 Aquatic vertebrates

The presence of PBDE depends mainly on the degree of bromination.
DeBDE, OBDE, and HxBDE were not found in mussel and fish samples
collected in Japan. No data are available for HpBDE. However, PeBDE
was found in mussel and fish species in concentrations of < 3 µg/kg
wet weight in Japan. Concentrations of 22 µg 2,2',4,4',5-PeBDE/kg wet
weight were found in cod liver collected in the North Sea, and
concentrations of up to 64 µg/kg on a fat basis were found in fish
collected in Sweden. The concentrations were much higher in fish
collected in the vicinity of industrial areas, e.g., up to 9.4 mg/kg
on a fat basis (Jansson et al., in press). Levels for TeBDE, mainly
2,2',4,4'-TeBDE, were comparable but generally higher. Mussels and

fish in Japan contained up to 14.6 µg/kg wet weight, cod liver
collected in the North Sea, 360 µg/kg, and eel from the Netherlands,
up to 1700 µg/kg fat. Different species of fish collected in Sweden
contained up to 88 mg/kg fat (Andersson & Blomkvist, 1981; Watanabe,
1987; Watanabe et al., 1987b; De Boer, 1989, 1990). An increasing
trend was observed in PeBDE and TeBDE levels in freshwater fish in
Sweden. Only limited data are available concerning lower brominated
PBDE (Jansson et al., in press).

Thirty-five samples of 18 freshwater fish collected in German
rivers, and 17 samples collected from the Baltic Sea and the North Sea
contained 18.2-983.6 and 0.6-119.9 µg PBDE/kg fat (determined as
Bromkal 70-SDE), respectively (Kruger, 1988).

6.7 Aquatic mammals

Three bottle-nose dolphins (Tursiops truncatus), collected
during the 1987/88 mass mortality event along the central and south
Atlantic coast of the USA, were analysed for brominated diphenyl
ethers. The concentrations of PBDE were 200, 220, and 180 µg/kg lipid
(Kuehl et al., 1991).

Limited data are available on the presence of PBDE in aquatic
mammals. 2,2'4,4'5-PeBDE was found in ringed and grey seals, collected
in Sweden, in concentrations of 1.7 and 40 µg/kg fat, respectively.
TeBDE, mainly 2,2',4,4'-TeBDE, was also found in the blubber of these
2 species in concentrations of 47 and 650 µg/kg fat, respectively
(Jansson et al., in press). Seals collected at Spitzbergen contained
approximately 10 µg PBDE/kg fat, determined as Bromkal 75DE (Kruger,
1988).

6.8 Terrestrial vertebrates

Pooled samples of rabbits, moose, and reindeer, collected in
Sweden, contained PeBDE and TeBDE in concentrations of <0.3, 0.64,
and 0.26 µg 2,2',4,4',5-PeBDE/kg and <2, 0.82, and 0.18 µg
2,2',4,4'-TeBDE/kg lipid, respectively (Jansson et al., in press).

Four samples of cow's milk were analysed in Germany for the
presence of PBDE. The average concentration was 3.572 µg/kg fat (range
2.536-4.539 µg/kg) determined as Bromkal 70-5DE. The main component
was HxBDE (Kruger, 1988).

6.8.1 Birds

Limited data are available on the presence of PBDE in birds. In
Sweden, 2,2',4,4',5-PeBDE was found in the muscle tissue of osprey, in
newborn starlings, and in guillemot eggs in concentrations of 140,
2.3-4.2, and 24-260 µg/kg lipid, respectively. A trend towards
increasing concentrations of PeBDE and TeBDE in guillemot eggs from
the Baltic Sea was observed. 2,2',4,4'-TeBDE was found in the muscle
tissue of osprey in concentrations of up to 1800 µg/kg. Guillemots
collected from the Baltic Sea, the North Sea, and Spitzbergen
contained 370, 80, and 130 µg/kg on a fat basis, respectively (Jansson
et al., 1987, 1993).

In the USA, indications were found that dibromodiphenyl ether was
present in the eggs of fish-eating birds, but it was not quantified
(Stafford, 1983).

6.8.2 Humans

In Germany, 25 samples of breast milk were analysed for the
presence of PBDE. The ages of the women ranged between 24 and 36 years
and most of them were breast-feeding their first or second child. The
samples contained 0.6-11.1 µg PBDE/kg fat, determined as Bromkal
70-5DE. The main component was HxBDE. One sample from a Chinese woman
showed 7.7 µg PBDE/kg fat; a sample from another woman, exposed
occupationally to hydraulic fluids and transformer oils, contained
50 µg PBDE/kg fat. This last value was excluded from the given range
and average. (Kruger, 1988).

DECABROMODIPHENYL ETHER

1. SUMMARY, EVALUATION, CONCLUSIONS, AND RECOMMENDATIONS

1.1 Summary and evaluation

1.1.1 Identity, physical and chemical properties

Typically, commercial DeBDE has a purity of 97-98%, with 0.3-3.0% of
nona- and/or octabrominated diphenyl ethers. Nonabromodiphenyl ether
(NBDE) is the major impurity. In contrast to the other polybrominated
diphenyl ethers there is only one isomer of DeBDE.

The melting point of DeBDE is approximately 300 °C and decomposition
occurs above 400 °C. Solubility in water is 20-30 µg/litre and the log
of the n-octanol/water partition coefficient is greater than 5.
Vapour pressure is < 10^-6 mmHg at 20 °C.

1.1.2 Production and uses

Among the brominated diphenyl ethers (mono- to deca-),
deca-bromodiphenyl ether is the most important commercial product with
regard to production and use.

Commercial DeBDE has been produced in increasing degrees of purity
since the late 1970s. The global production of DeBDE is approximately
30 000 tonnes/year. It is used as an additive flame retardant in many
plastics, especially high-impact polystyrene, and in the treatment of
textiles used in soft furnishing, automobile fabrics, and tents.

1.1.3 Environmental transport, distribution, and transformation

Photodegradation of DeBDE occurs in organic solvents under
ultraviolet radiation (UVR) or sunlight; lower brominated diphenyl
ethers and brominated dibenzofurans are formed. Photodegradation also
occurs, to a lesser extent, in water with sunlight; however, lower
brominated diphenyl ethers and brominated dibenzofurans have not been
found.

Levels of DeBDE extracted from polymers are close to, or below,
the limit of detection, depending on the polymer type and extraction
solvent.

Because of its extremely low water solubility and vapour pressure,
DeBDE is likely to be transported primarily by adsorption to
particulate matter. It is persistent and likely to accumulate in
sediment and soil.

No data are available on its bioavailability from sediment and
soil. A study on rainbow trout did not show any bioaccumulation in
flesh, skin, or viscera, over 48 h. DeBDE is unlikely to bioaccumulate
because of its high relative molecular mass.

Products containing commercial DeBDE will eventually be disposed
of by landfill or incineration. DeBDE may eventually leach from
landfills. Polybrominated dibenzofurans (PBDF) and mixed
halogen-dibenzofurans and -dibenzodioxins may result from landfill
fires and inefficient incineration. Products containing commercial
DeBDE may contribute to these emissions.

Pyrolysis of both commercial DeBDE itself and polymers (HIPS, PBT,
industrial polypropylene) containing DeBDE, in the presence of oxygen,
produced PBDF, polybrominated dibenzodioxins (PBDD) being found to a
lesser extent. The maximum formation' of PBDF occurs at 400-500 °C,
but it can occur at temperatures up to 800 °C, and Sb₂O₃ plays a
catalytic role in the formation of PBDF and PBDD.

The formation, and amounts found, of PBDF and PBDD depend on
temperature, oxygen content, and length of pyrolysis. In the absence
of oxygen, mainly polybromobenzenes and polybromonaphthalenes are
formed.

1.1.4 Environmental levels and human exposure

DeBDE has been identified in air in the vicinity of manufacturing
plants at concentrations of up to 25 µg/m³. DeBDE was not detected in
water samples collected in Japan in the period 1977-91. However, it
was detected in river and estuarine sediment, collected in Japan in
the same period, at concentrations of up to approximately 12 mg/kg dry
weight. DeBDE (up to 1 g/kg) was also found in the USA in river
sediment close to one manufacturing plant. DeBDE was not detected in
fish samples collected in Japan, but, in one mussel sample, a level
just above the level of detection was found. DeBDE was not detected in
human adipose tissue samples collected in Japan, but, in the USA,
DeBDE was found in 3 out of 5 samples of human adipose tissue.

Human exposure to DeBDE can occur in the course of manufacture and
formulation into polymers. Exposure of the general population to DeBDE
is insignificant.

Determination of occupational exposure to the breakdown products
of DeBDE during manufacture, formulation, or use, showed that air
samples close to the extruder head contained high concentrations of
PBDF. Lower levels were found in the air of the workroom. PBDF was
also found in wipe samples. The application of good engineering
techniques has been shown to reduce occupational exposure to PBDF.

Exposure of, the general population to PBDF impurities in flame
retarded polymers is unlikely to be of significance.

1.1.5 Kinetics and metabolism in laboratory animals and humans

DeBDE is poorly absorbed from the gastrointestinal tract and is
rapidly excreted following injection.

The results of metabolic studies on the rat, using ¹⁴C labelled
DeBDE, indicated a half-life for the disappearance from the body of
less than 24 h and that the principal route of elimination following
oral ingestion was via the faeces. No appreciable ¹⁴C activity (less
than 1%) was found in either urine or expired air.

Rats fed 0.1 mg/kg body weight per day, for up to two years,
showed no accumulation of DeBDE in serum, kidneys, muscle, or testes,
as estimated from total bromine determination. Bromine accumulation in
the liver plateaued at 30 days and was cleared within 10 days
following treatment. After 180 days of treatment, the bromine level in
the liver of treated rats was no greater than that in control rats.
Adipose tissue accumulated low levels of total bromine, which remained
after 90 days of clean diet; the nature of the retained "bromine" is
not known. Since DeBDE accounted for only 77% of the commercial
mixture used, "bromine" could have been derived from NBDE or OBDE.

1.1.6 Effects on laboratory mammals and in vitro test systems

The acute toxicity of DeBDE for laboratory animals is low. The
substance is not an irritant to the skin or eyes of rabbits. It is not
chloracnegenic on the skin of rabbits and is not a human skin
sensitizer.

The combustion products of flame retarded polystyrene containing
DeBDE and Sb₂0₃ were tested for acute toxicity and comedogenicity.
The rat oral LD₅₀ of the soot and char was >2000 mg/kg body weight.

In short-term toxicity studies on rats and mice, DeBDE (purity
>97%) at dietary levels of 100 g/kg (4 weeks) or 50 g/kg (13 weeks;
equivalent to 2500 mg/kg body weight for the rat) did not induce
adverse effects. A one-generation reproduction study on rats showed no
adverse effects with dose levels of 100 mg/kg body weight. DeBDE did
not cause any teratogenic effects in the fetuses of rats administered
a dose level of 100 mg/kg body weight. With 1000 mg/kg body weight,
malformations, such as delayed ossification, were seen. DeBDE was not
shown to be mutagenic in a number of tests.

In a carcinogenicity study on rats and mice, DeBDE (purity 94-99%)
was administered at dietary levels of up to 50 g/kg. An increase in
the incidence of adenomas (but not carcinomas) was found in the livers
of male rats receiving 25 g/kg and female rats receiving 50 g

DeBDE/kg. In male mice, increased incidences of hepatocellular
adenomas and/or carcinomas (combined) were found at 25 g/kg and an
increase in thyroid follicular cell adenomas/ carcinomas (combined) at
both dose levels. Female mice did not show any increase in tumour
incidence. There was equivocal evidence for carcinogenicity in male
and female rats and male mice only at dose levels of 25-50 g DeBDE/kg
diet. As the results of all mutagenicity tests have been negative, it
can be concluded that DeBDE is not a genotoxic carcinogen. IARC (1990)
concluded that there was limited evidence for the carcinogenicity of
DeBDE in experimental animals. The very high dose levels, lack of
genotoxicity, and minimal evidence for carcinogenicity indicate that
DeBDE, at the present exposure levels, does not present a carcinogenic
risk for humans.

1.1.7 Effects on humans

No evidence for skin sensitization was found in 200 human subjects
exposed to DeBDE in a sensitization test.

A morbidity study of extruder personnel blending
polybutyl-eneterephthalate containing DeBDE, with consequently
potential exposure to PBDD and PBDF for 13 years, did not reveal any
deleterious effects, even though 2,3,7,8-TeBDF and -TeBDD were
detected in the blood. Results of immunological studies showed that
the immune system of the exposed persons was not adversely affected in
13 years.

1.1.8 Effects on other organisms in the laboratory and field

The EC₅₀s for the growth of 3 marine unicellular algae were
greater than 1 mg DeBDE/litre. No further information is available on
the effects of DeBDE on other organisms in the laboratory and field.

1.2 Conclusions

1.2.1 DeBDE

DeBDE is widely used incorporated in polymers as an additive flame
retardant. Contact of the general population is with products made
from these polymers. Exposure is very low since the DeBDE is not
readily extracted from polymers. The acute toxicity of DeBDE is very
low and there is minimal absorption from the gastrointestinal tract.
Thus, risk to the general population from DeBDE is considered to be
insignificant.

Occupational exposure is to DeBDE in particulate form. The control
of dust during manufacture and use will adequately reduce the risk for
workers.

DeBDE is persistent and binds to particulate matter in the
environment; it is likely to accumulate in sediment. It is unlikely to
bioaccumulate. Current evidence suggests that environmental
photodegradation in water does not lead to the formation of lower
brominated diphenylethers or brominated dibenzofurans, but little is
known about degradation in other media.

There is minimal information on the toxicity of DeBDE for
organisms in the environment.

1.2.2 Breakdown products

Formation of PBDF and, to some extent, PBDD may occur when DeBDE,
or products containing it, are heated to 300-800 °C. The possible
hazards associated with this have to be addressed.

Properly controlled incineration does not lead to the emission of
significant quantities of brominated dioxins and -furans. Any
uncontrolled combustion of products containing DeBDE can lead to an
unquantified generation of PBDF/PBDD. The significance of this for
both humans and the environment will be addressed in a future
Environmental Health Criteria on PBDF/PBDD.

PBDF have been found in the blood of workers involved in the
production of plastics containing DeBDE. No adverse health effects
have been associated with this exposure. Good engineering controls can
prevent worker exposure to PBDF.

1.3 Recommendations

1.3.1 General

* Workers involved in the manufacture of DeBDE and products
containing the compound should be protected from exposure through
the application of appropriate industrial hygiene measures, the
monitoring of occupational exposure, and engineering controls.

* Environmental exposure should be minimized through the appropriate
treatment of effluents and emissions in industries using the
compound or products. Disposal of industrial wastes and consumer
products should be controlled, to minimize environmental
contamination with this persistent material and its breakdown
products.

* Manufacturers should minimize levels of impurities in commercial
DeBDE products, using the best available techniques. A purity of
97% or higher is recommended.

* Incineration should only be carried out in properly constituted
incinerators, running at consistently optimal conditions. Burning
by any other means may lead to the production of PBDF and/or PBDD.

1.3.2 Further studies

* Further studies on the bioavailability and toxicity of
sediment-bound DeBDE should be performed on relevant organisms.

* Continued monitoring of environmental levels is required.

* The generation of PBDF under real fire conditions should be
further investigated.

* Environmental biodegradation, and photodegradation in compartments
other than water, should be further studied.

* Investigation into possible methods and consequences of recycling
of DeBDE-containing polymers should be made.

* Analytical methods for DeBDE in various matrices should be
validated.

2. IDENTITY, PHYSICAL AND CHEMICAL PROPERTIES, ANALYTICAL METHODS

2.1 Identity

2.1.1 Pure substance

Chemical structure:

Chemical formula: C₁₂Br₁₀O

Relative molecular mass: 959.22

Chemical name: decabromodiphenyl ether
(DeBDE); decabromodiphenyl
oxide

CAS registry number: 1163-19-5
(61345-53-7, mixture of
decabromodiphenyl oxide and
Sb₂O₃)

CAS name: 1,1'-oxybis[2,3,4,5,6-pentabromo]-
benzene

IUPAC name: bis(pentabromophenyl) ether

EINECS registry number: 214604

MITI number: 3-2846

Synonyms: decabromobiphenyl ether;
decabromobiphenyl oxide;
Decabrom; ether,
bis(pentabromophenyl);
ether, decabromodiphenyl

From: US EPA (1984); Ethyl Corp. (1992a).

On the basis of the chemical structure, decabromodiphenyl ether is
fully brominated and there is only one congener.

2.1.2 Technical product

Trade names: FR-300 BA; DE-83-RTM; Saytex
102; Saytex 102E; FR-1210;
Adine 505; AFR 1021;
Berkflam B10E; BR55N;
Bromkal 81; Bromkal 82-ODE;
Bromkal 83-10 DE; Caliban
F/R-P 39P; Caliban F/R-P 44;
Chemflam 011; DE 83; DP 10F;
EB 10FP; EBR 700; Flame Cut
BR 100; FR 300BA; FR P-39;
FRP 53; FR-PE; FR-PE(H);
Planelon DB 100; Tardex 100;

Trade names (contd) NC-1085; HFO-102; Hexcel PF1;
Phoscon Br-250; NCI-C55287
Caliban-F/RP-44 is a DeBDE
mixture with antimony oxide,
and, F/RP-53 contains 60% DeBDE,
which is used in conjunction with
THP-salts finishes and an acrylic
binder.

Commercial DeBDE is typically composed of 97-98% decabromodiphenyl
ether with 0.3-3.0% other brominated diphenyl ethers (BFRIP, 1990)
(see Table 1). Nonabromodiphenyl ether isomers are the major
impurities. The commercial product typically contains a minimum of
81-83% bromine (IARC, 1990) (83% theoretical; Ethyl Corp. 1992a).

Differences in manufacturing processes affect the nature and
amounts of impurities in the product (Larsen, 1980). Today's
commercial product is considerably purer than that manufactured in the
past. Isomers of nonabromodiphenyl ether and octabromodiphenyl ether
have been reported as impurities in DeBDE (Timmons & Brown, 1988).
FR-300-BA, produced in the early 1970s (no longer a commercial
product), was composed of 77.4% DeBDE, 21.8% NBDE, and 0.8% OBDE
(Norris et al., 1975c). Later production of DeBDE, by the same
manufacturer, ranged in composition from 94 to 99% DeBDE with 0.3-4.5%
impurities (NBDE isomers were identified as the major impurities)
(NTP, 1986). Other DeBDE products, e.g., DE-83, Saytex 102E, and
Bromkal 82-ODE have a purity of approximately 93 to 98.5% with
different quantities of impurities (Dow Chem. Comp., 1978; De Kok et
al., 1979; Davidson & Ariano, 1986).

The availability of a technical product (possibly FR-1208) of
88.1% purity containing 11% nona-, and 0.5% octabromodiphenyl ether,
and 0.1% hexabromobenzene has been reported (Klusmeier et al., 1988).

In Japan, a DeBDE is produced containing about 3% of
nonabromodiphenyl ether as an impurity (Watanabe & Tatsukawa, 1987).

2.2 Physical and chemical properties

Commercial DeBDE is a free-flowing, odourless, off-white powder,
with a bromine content of 81-83% and a high melting point.

Melting point: 290-306 °C

Decomposition point, >320, >400, and 425 °C
DTA (different products)

Volatility: 1% 319 °C
TGA (% weight loss) 5% 353 °C
10% 370 °C
50% 414 °C
90% 436 °C

Specific gravity: 3.0, 3.25 at 20 °C

Decabromodiphenyl ether

Vapour pressure: <10^-6 20 °C
(mmHg) <1 250 °C
2.03 278 °C
5.03 306 °C

Solubility: water 20-30 µg/litre
(at 25 °C) cottonseed oil 600 mg/litre
saturated copra oil 920 mg/litre
acetone 0.5, 1.0 g/litre
benzene 1.0, 4.8 g/litre
chlorobenzene 6.0 g/litre
methylene bromide 4.2 g/litre
methylene chloride 1.0, 4.9 g/litre
o-xylene 8.7 g/litre
methanol 1 g/litre
toluene 2 g/litre
methyl ethyl ketone 1 g/litre
pentane <1 g/litre
styrene <1 g/litre

Stability: stable under normal temperatures and
pressures

Flash-point: none

Flammability: non-flammable

Autoignition point: not applicable

n-Octanol/water
partition
coefficient
(log P_ow): 5.24; 9.97*

From: Norris et al. (1973, 1974, 1975a,c); Tabor & Bergman (1975);
US EPA (1986); Chemag. (1988); Great Lakes Chemical Corporation
(1990b); IARC (1990); Kopp (1990); Watanabe & Tatsukawa (1990)*;
Bromine Compounds Ltd. (1992); Ethyl Corp. (1992a).

2.3 Analytical methods

The detection and quantification of DeBDE have been investigated
by several authors. The methods are based on gas-liquid
chromatographic separation using different detection methods, such as
electron capture detection and mass spectrometry (see General
Introduction, section 2.1 and Table 2).

3. SOURCES OF HUMAN AND ENVIRONMENTAL EXPOSURE

3.1 Natural occurrence

DeBDE has not been reported to occur naturally (see General
Introduction, section 1.1).

3.2 Anthropogenic sources

3.2.1 Production levels and processes

DeBDE is produced by the bromination of diphenyl oxide in the
presence of a Friedel-Crafts catalyst (Larsen, 1978). It is
manufactured in a batch process in enclosed vessels during both the
reaction and the drying cycle (US EPA, 1988; IARC, 1990).

Commercial production of DeBDE in the USA began in 1976. Among
brominated flame retardants, the quantities produced rank second only
to the quantities of tetrabromobisphenol A. There are 2 manufacturers
in the USA (BFRIP, 1992). IARC (1990) reported 2 manufacturers in
Belgium, 1 each in Switzerland, the United Kingdom, and Israel, and 5
in Japan (US EPA, 1988).

About 30 000 tonnes of DeBDE are used annually throughout the
world. About 40% of this total is used (in combination with antimony
trioxide) in high-impact polystyrene applications, such as television
and radio cabinets. Textile applications, such as a polyester fibre
additives and coatings for automobile fabric, tarpaulins, and tents
account for about 900 tonnes (IARC, 1990; OECD, 1991; Arias, 1992).

The annual consumption of DeBDE in Japan was 1000 tonnes in 1976,
2900 tonnes in 1984, 4000 tonnes in 1987, and 9800 tonnes in 1991,
mainly used for polystyrene, polyester, and polypropylene (Watanabe,
1987; Watanabe et al., 1987b; Watanabe et al., undated). Recently
published figures from a Japanese study showed that the consumption of
PBDE (mainly DeBDE) in Japan was about 20-30% of the total consumption
of brominated flame retardants (OECD, 1991).

In the Federal Republic of Germany, 1800-2000 tonnes were used in
plastics in 1988. DeBDE mixed with antimony trioxide and DeBDE used in
conjunction with tetrakis (hydroxymethyl) phosphonium (THP) salt
finishes and an acrylic binder are used to blend 50/50 and 65/35 with
polyester/cotton (Ulsamer et al., 1980).

An estimation of the use of decabromodiphenyl ether in the
Netherlands in 1988 was 1100-1300 tonnes (Anon, 1989).

3.2.2 Uses

DeBDE is a non-reactive, additive flame retardant widely used for
its high bromine content, thermal stability, and cost effectiveness.
It is used in thermoplastic resins, thermoset resins, textiles,
adhesives, and coatings. The major applications are for high-impact
polystyrene, cross-linked polyethylene polybutyl-eneterephthalate,
glass-reinforced thermoset and thermoplastic polyester moulding
resins, low density polyethylene extrusion coatings, non-drip
polypropylene (homo and copolymers), acrylo-nitrile-butadiene-styrene
rubber (ABS), nylon, adhesives, epoxy resins, polyvinylchloride, and
elastomers. The concentrations of DeBDE in the polymers range from 6
to 22% (Tabor & Bergman, 1975; Flick, 1986; NTP, 1986; Kaart & Kokk,
1987; IARC 1990).

A mixture of DeBDE and antimony trioxide has been used to treat
nylon and polyester/cotton fabrics for industrial safety apparel and
tents (LeBlanc, 1979). DeBDE is also used in the insulating materials
for wire and electrical cable (IARC, 1990).

In the United Kingdom, approximately 1000-1200 tonnes DeBDE is
used per year in the textile industry (back coatings on synthetic
fibres) (United Kingdom Department of Environment, 1992).

4. ENVIRONMENTAL TRANSPORT, DISTRIBUTION, AND TRANSFORMATION

4.1 Transport and distribution between media

4.1.1 Extraction from polymers

Pellets of ABS (acrylonitrile-butadiene-styrene) terpolymer and
polystyrene containing 10% DeBDE, were placed in 2 litres of water and
shaken mechanically. Total bromine in water was estimated after 3 h
and up to 187 h. Extraction of bromine took place from the ABS, during
the first 43 h, in concentrations ranging from <1.0 to 3.7 mg/litre.
No bromine was extracted from polystyrene (limit of determination
<0.5 mg/litre). Because there was no increase in bromine
concentration with time, it was suggested by the authors that the
levels found were due to erosion and not to extraction. Extraction
studies were also carried out under static conditions with pellets of
ABS containing 4.25% DeBDE. Water, acetic acid, and cottonseed oil
were used as extraction solvents at temperatures of approximately 50
or 60 °C, during 1 or 7 days. Extraction occurred only with cottonseed
oil (7 days, 60 °C) at 1 mg DeBDE/litre (limit of determination
0.075 mg/litre) (Norris et al., 1973, 1974, 1975a).

4.2 Biotransformation

No data are available.

4.3 Abiotic degradation

4.3.1 Photodegradation

Studies have been performed on the photodegradation of DeBDE in
organic solvents and water. Organic solvents were used in the initial
photodegradation studies because of the extremely low water solubility
of DeBDE. In xylene, DeBDE was photodegraded by reductive
debromination with a half-life of 15 h (Norris et al., 1973, 1975a).

A commercial mixture of DeBDE containing traces of a
nonabromodiphenyl ether, was irradiated in hexane solution with UVR
and sunli