Summary of Technical Review Comments on the OctaBDE Risk Profile under the
UNECE-LRTAP POPs Protocol
Introduction
Commerical octaBDE (CAS Number: 32536-52-0), is a complex mixture of several polybrominated
diphenyl ethers with varying degrees of bromination, typically consisting of penta-, hexa-, hepta-,
octa-, nona-, and deca-bromodiphenyl ether isomers.
OctaBDE belongs to a larger group of polybrominated diphenyl ethers that are used as flame
retardants mostly in applications in the plastics and textile industries.
The European Union has submitted a dossier, “Risk Profile and Summary Report for
Octabromodiphenyl ether, August 2005”, to nominate octaBDE for inclusion into the United Nations
Economic Commission for Europe (UNECE) Annex 1 of the Protocol to the Convention on Longrange Transboundary Air Pollution (LRTAP) on Persistent Organic Pollutants (POPs). The
information in the dossier focuses on the POP characteristics of the commercial octaBDE formulation
and is, to a large extent, based on the EU Risk Assessment Report (European Commission 2003).
Therefore this review deals also with the congeners contained in the product. The dossier concludes
that the commercial octaBDE product meets the Executive Body Decision 1998/2 criteria under the
UNECE LTRAP POPs protocol for persistence, potential long-range environmental transport,
potential to cause adverse effects, and bioaccumulation.
Five independent referees reviewed the dossier on OctaBDE and submitted their referee reports to the
coordinator. This summary is based on four of the referee reports. One review (review D) was not used
in preparing this summary as it did not provide a final conclusion on the dossier in meeting the
indicative values. It was also prepared in a deviating format.
Method
As instructed, the technical content of the dossier was critically examined and evaluated against the
requirements outlined in the Executive Body Decision 1998/2. The dossier was analysed on reliability,
transparency, and completeness, and the degree to which the information provided supports the
proposal. The factors that have been taken into account for the conclusions on para. 2 a-b of EB
1998/2 were also recorded. Additional information considered for octaBDE included the January 20,
2006 summary of comments on octaBDE.
Various reviewers retrieved open literature in order to check if the dossier was up-to-date and if this
additional information was in line with the information in the dossier. However, this information was
not considered in deciding if the indicative values are met or not.
Summary review
POP characteristics-Summary of dossier in terms of the guidance and indicative numerical values
provided in Executive Body Decision 98/2 for:
a) Potential for long-range atmospheric transport
In the EB decision 1998/2 the potential for long-range transboundary atmospheric transport is outlined
as: “Evidence that the substance has a vapor pressure below 1,000 Pa and an atmospheric half-life
greater than two days. Alternatively, monitoring data showing that the substance is found in remote
regions.”
reviewer A: Based on the reported vapor pressure and atmospheric half-life, and possible adsorption
onto atmospheric particles, the dossier concludes that the potential for long-range atmospheric
transport for octaBDE is supported. Using the category approach, the dossier further suggests that
data available for the lower and higher brominated congeners showing their potential for long-range
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atmospheric transport can also be used to support a concern that octaBDE would behave similarly.
reviewer B: The proposal refers to the data evaluated during the EU risk assessment procedure on
octaBDE. It shows that the indicative numerical values given in EB 1998/2 regarding vapour pressure
and atmospheric half-life are exceeded. Monitoring data from remote regions show that also higher
brominated congeners are susceptible to long range atmospheric transport.
Reviewer C: The information provided in the dossier is sufficient. OctaBDE meets the indicative
values mentioned in EB 1998/2 for potential for long-range transboundary atmospheric transport. The
conclusion was based on vapour pressure and half-life in the atmosphere.
Reviewer E: Commercial octaBDE technically satisfies the screening requirement for the potential for
long-range transboundary atmospheric transport when attached to particles;
Overall conclusion
All reviewers concluded that the commercial OctaBDE meets the indicative value for long-range
transboundary atmospheric transport. This conclusion is based on vapour pressure and half-life.
Furthermore it is stated that monitoring data show the suspectibility to long range atmospheric
transport of some components of OctaBDE.
b) Toxicity and Ecotoxicity
Toxicity is described in the EB 1998/2 decision as: “potential to adversely affect human health and/or
the environment.” No further indicative values on toxicity are given in the EB 1998/2 decision.
Reviewer A: The dossier further states that the EU Risk Assessment recommended that octaBDE be
classified as “Toxic”, and that the commercial octaBDE product fulfills the Executive Body Decision
1998/2 criteria with regard to the potential for adverse effects on human health or the environment.
reviewer B: Based on the hazard potential concerning human health and concern of toxic effects to
predators octaBDE fulfils the requirement of EB Decision 1998/2 with regard to the potential for
adverse effects on human health and /or the environment.
Reviewer C: The information provided in the dossier is sufficient. OctaBDE meets the criteria
mentioned in EB 1998/2 for toxicity and ecotoxicity, at least due to the lower brominated diphenyl
ethers in the commercial mixture.
Reviewer E: Commercial octaBDE has the potential to adversely affect human health and/or the
environment.
Overall conclusion
All reviewers concluded that the commercial OctaBDE meets the indicative value for toxicity and
ecotoxicity
c) Persistence
In the EB 1998/2 decision persistence is defined as: “evidence that the substance's half-life in water is
greater than two months, or that its half-life in soils is greater than six months, or that its half-life in
sediments is greater than six months.” Alternatively, evidence that the substance is otherwise
sufficiently persistent to be of concern within the scope of the protocol may also fulfill this criterion.
Reviewer A: The dossier reports that available laboratory test data indicate octaBDE is expected to
have mineralization half-lives greater than 2 months in water and greater than 6 months in soils and
sediment, and concludes that octaBDE is considered to be persistent in the environment.
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reviewer B: The proposal concludes that octaBDE is persistent in the environment. However under
certain environmental conditions (e.g. anaerobic state in soil) degradation might occur leading to the
formation of lower brominated congeners, which are also of high concern. The proposal reported no
experimentally determined half-lives. However, from the information submitted it can be concluded
that the indicative numerical values given in EB 1998/2 are likely to be met and that the substance is
sufficiently persistent to be of concern within the scope of the protocol.
Reviewer C: The information provided in the dossier, is sufficient. OctaBDE meets the criteria
mentioned in EB 1998/2 for persistency. The conclusion was based on the fact that the based on
available laboratory test data, octaBDE is considered to be persistent in the environment and is
expected to have mineralization half lives of >2 months in water and >6 months in soil and sediment.
This was supported by literature data on congeners present in OctaBDE.
Reviewer E: Commercial octaBDE meets the LRTAP POPs guidance for environmental persistence
Overall conclusion
All reviewers concluded that the commercial OctaBDE meets the indicative value for persistence.
The reviewers cited the mineralization half lives of >2 months in water and >6 months in soil and
sediment mentioned in the dossier.
d) bioaccumulation
In EB 1998/2 decision bio-accumulation: (i) Evidence that the BCF or BAF for the substance is
greater than 5,000 or the log Kow is greater than 5; or (ii) Alternatively, if the bio-accumulative
potential is significantly lower than (i) above, other factors, such as the high toxicity of the substance,
that make it of concern within the scope of the protocol.
Reviewer A: The dossier concludes that an assessment of the bioaccumulation potential of commercial
octaBDE is complicated by the fact that it is a complex mixture of several polybrominated diphenyl
ethers with varying degrees of bromination, and that the bioaccumulative properties vary with bromine
content. The dossier cites a log octanol-water partition coefficient (Kow) of 6.29 for commercial
octaBDE and suggests that experimental results indicate octaBDE does not bioconcentrate. The
dossier concludes that no significant bioconcentration of octaBDE itself is expected, but the lower
brominated congeners that are components of the commercial mixture (pentabromodiphenyl ether and
hexabromodiphenyl ether) are considered to be highly bioaccumulative, with BCFs greater than 5,000.
reviewer B: The assessment of the bio-accumulation potential of commercial octaBDE is not
unambiguous. The log Kow representing the first screening criteria for bio-accumulation exceeds the
indicative numerical value according EB 1998/2.
BCF values in aquatic organisms span a range from 5 600 to < 9.5, the main components hepta- and
octaBDE exhibit BCFs < 100. However evidence exists that higher brominated congeners metabolise
to less brominated compounds which are also of high concern.
Available monitoring data on PBDEs including heptaBDE show trophic transfer and indications for
ecological magnification.
Though not all indicators for bio-accumulation are met by all components of commercial octaBDE
there is sufficient information available that bio-accumulation does occur from the release of
commercial octaBDE in the environment.
Reviewer C: The information provided in the dossier is sufficient. OctaBDE meets the criteria
mentioned in EB 1998/2 for bioaccumulation.
The log Kow reported in the dossier is 6.29. The dossier concludes that based on its octanol-water
partition coefficients octaBDE would be expected to be bioaccumulative, but that experimental results
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indicate that octaBDE does not bioconcentrate, probably due to its large size precluding crossing of
cell walls in organisms. Additional literature is provided. Sellström et al (2005) provides an excellent
figure (Figure 2) on the relationship between logKow and bioaccumulation from soil/sediment to
animal factor (BSAF). It shows that also in the higher brominated diphenyl ethers a high
bioaccumulation factor can be expected.
Reviewer E: OctaBDE does not meet the LRTAP POPs guidance for bioaccumulation based on the
evidence presented. Information beyond that conveyed in the risk profile is available for consideration
of the <12% hexaBDE component
Overall conclusion
Three reviewers concluded that the commercial OctaBDE meets the indicative value for
bioaccumulation. These reviewers mentioned that the log Kow representing the first screening
criterion for bio-accumulation exceeds the indicative numerical value according EB 1998/2. They
also indicated that the assessment of the bio-accumulation potential of commercial octaBDE was
not unambiguous as the commercial OctaBDE is a mixture of BDE’s with different characteristics
and as experimental results show that octaBDE does not concentrate. Reviewer number 4
concluded that OctaBDE does not meet the POPs guidance for bioaccumulation based on
evidence presented. However, this reviewer stated that information beyond that conveyed in the
risk profile is available for consideration of the <12% hexaBDE component
Monitoring or equivalent scientific information suggesting long-range transboundary
atmospheric transport – Summary of the dossier in terms of EB Decision 1998/2-2a
Reviewer A: According to the dossier, available monitoring data show that octaBDE is found mainly
in soils and sediments close to sources of release; monitoring data for remote areas are not available
for octaBDE itself. To fill this data gap, the dossier uses the category approach and considers the
available data for the lower and higher brominated congeners to support a concern for the long-range
transboundary atmospheric transport. Additional support comes from the vapor pressure and
atmospheric half-life, which appear to meet the Executive Decision 1998/2 screening criteria.
Reviewer B: Though monitoring data on octaBDE isomers are scare sufficient information exists that
some congeners contained in octaBDE formulations undergo LRAT and are liabel to bio-accumulate
in apical arctic predators.
The profile of commercial octaBDE concerning monitoring data is less detailed but serves the purpose
to show that these compounds are detected in abiotic and biotic samples in regions far from their
source.
Reviewer C: The dossier concludes that there are no monitoring data from remote locations available
for octaBDE itself. The available monitoring data generally show that octaBDE is found mainly in
sediments and mainly close to sources of release.
Limited monitoring data in air from remote areas of Sweden found no octaBDEs to be present, but
found indications of the presence of hexabromodiphenyl ethers and heptabromodiphenyl ethers
associated with the particulate phase. The dossier also concludes that the lower brominated congeners
(e.g. pentabromodiphenyl ethers and hexabromodiphenyl ethers) present in the commercial octaBDE
appear to be subject to long-range environmental transport, possibly by the atmosphere, as they are
widely found in sediment and biota in remote areas.
Reviewer E: Commercial octaBDE does not exhibit the semivolatile properties and propensity for
LRAT that are the hallmarks of most problematic POPs. HexaBDE has been detected more regularly
and at higher concentrations in remote locations and may be more likely subject to LRAT.
Overall conclusion
Three reviewers indicate that there are no or limited data from remote areas, but that the dossier
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points out that sufficient information exists that some congeners contained in octaBDE
formulations undergo LRAT. The fourth reviewer indicate that commercial octaBDE does not
exhibit the semivolatile properties and propensity for LRAT, but that hexaBDE has been detected
more regularly and at higher concentrations in remote locations and may be more likely subject to
LRAT. HexaBDE is one of the congeners present in commercial OctaBDE (<12%)
Sufficiency of the information to suggest that the substance is likely to have significant adverse
human and/or environmental effects resulting from its long-range transboundary atmospheric
transport – Summary of the dossier in terms of EB Decision 1998/2-2b
Reviewer A: Sufficient or suitable information was not presented in the dossier and therefore the
proposal does not meet the criteria to support the statement whether commercial octaBDE is likely to
have significant
adverse human and/or environmental effects resulting from its long-range transboundary atmospheric
transport.
Reviewer B: Though congeners contained in commercial octaBDE do not belong to the most abundant
PBDEs detected in the environment their hazard profile combined with their ubiquitous occurrence in
the environment including top predators far from their sources implicates that adverse effects on
human health and the environment cannot be excluded.
Reviewer C: The dossier concludes that available data indicate that penta- and hexabromo diphenyl
ethers have a much higher bioconcentration potential than the other components of octaBDE and so
are likely to have a higher potential to cause adverse effects on organisms in the environment.
Therefore the presence of lower brominated diphenyl ethers in the commercial octaBDE products is of
concern.
Reviewer E: No information is provided in the dossier to support a determination that commercial
octaBDE is likely to have significant adverse effects resulting from its long-range atmospheric
transport.
Overall conclusion:
Two reviewers (B & C) conclude that by using a category approach, the available data for the
bioconcentration potential of the lower brominated congeners present in the commercial octaBDE
mixture, support a concern for environmental effects.
One reviewer (A) concludes that the dossier provide no information to support that commercial
octaBDE is likely to have significant adverse effects resulting from its long-range atmospheric
transport and one reviewer(E) concludes that the dossier does not specifically address nor provide
evidence to support the specific statement linking effects to long-range transport, that is, "that
commercial octaBDE is likely to have significant adverse human and/or environmental effects
resulting from its long-range transboundary atmospheric transport".
Conclusions on the technical content of the dossier
Reviewer A: "For the most part, while the dossier provided a reasonable and logical case in favor of
supporting the proposal that commercial octaBDE meets the individual screening criteria outlined in
the Executive Decision 1998/2 for persistence, potential long-range environmental transport, potential
to cause adverse effects, and bioaccumulation, sufficient or suitable information was not presented in
the dossier and therefore the proposal does not meet the criteria to support the statement whether
commercial octaBDE is likely to have significant adverse human and/or environmental effects
resulting from its long-range transboundary atmospheric transport. Moreover, in order to fill data gaps
where data on commercial octaBDE were limited or altogether absent, the dossier uses the category
approach to support a concern. This approach is entirely reasonable; however, there are some instances
where the relevancy of using data from other lower or higher brominated congeners is not completely
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clear, or lacking in sufficient detail to support using them, leaving the reader with many unanswered
questions. In most of these instances, a stronger case could be made by simply adding more complete
detailed information. The reviewer mentions examples where insufficient information is presented or
where transparency is lacking, e.g., toxicological data."
Reviewer B: The technical content of the dossier is robust and sufficient to fulfil the requirements of
EB 1998/2. Most information contained in the proposal originates from the EU Risk Assessment
Report, which can be regarded as trustable and a high rated data source. However some sections could
be more elaborated e.g. toxicological data. Also the consideration of recent research and work could
have strengthened the proposal. It was not always clear if information/test results refer to the octaBDE
isomers or to the commercial formulation.
Reviewer C: The dossier is written in a compact and easy readable style. The literature used in the
dossier is up-to-date. The dossier provides enough information for screening against the indicative
values of the POP characteristics.
Reviewer E:
The risk profile, although dated August 2005, is several years out of date regarding the scientific
literature, relying primarily on an EU Risk Assessment Report (2003) where data collection had
terminated in 2002.
Overall, the risk profile was concisely written and consistent with the 2003 European Union Risk
Assessment Report on octaBDE on which it was based. A central finding of the EU Report
highlighted that there is a need for further information and/or toxicity testing. This is noteworthy
because the date of last literature search and technical review for the EU Report was in 2002 (EU
Report 2003) and, although the LRTAP risk profile was prepared in August 2005, it contains virtually
none of the extensive contemporary literature on the PBDEs published during this interval. This is a
serious deficiency. The deficiency is more noteworthy as this concern for contemporary information
was raised during the previous reviews of LRTAP risk profiles, but does not appear to have been
addressed. A single supplementary citation submitted by the Canadian government for consideration
(Gerecke et al., 2005), while informative regarding debromination potential, does not compensate for
the volume and quality of research undertaken in over the last three to four years.
Several of the LRTAP EB Decision 1998/2 requirements were not addressed, notably EB Decision
98/2 2(a) and 2(b), precluding the ability to conclude that they have been satisfied.
Overall conclusion
The reviewers stated that for the most part, the dossier provided a reasonable and logical case in
favor of supporting the proposal. The risk profile was concisely written and consistent with the
2003 European Union Risk Assessment Report. However, it was also mentioned that in many
instances, the dossier is lacking in transparency, completeness, and in sufficient detail to support
the proposal and that the dossier does not contain the most recent literature. Reviewer no. 4 even
states ‘Ít contains virtually none of the extensive contemporary literature on the PBDEs published
during this interval (2002-2005). Two reviewers indicate that the dossier does not specifically
address nor provide evidence in support of EB decisions 98/2 2(a) and 2(b) and indicate this is a
serious deficiency. Guidance of the EB on the precise interpretation of decisions EB 1998/2 2a
and 2b concerning the dossier requirements and the reviewers task would be welcome.
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