Deca-brominated diphenyl ether (deca-BDE) and hexabromocyclododecane (HBCD) are increasingly replacing penta- and octa-BDEs, which were banned after risk assessments carried out under the EU existing substances Directive classed them as persistent, bioaccumulative and toxic (PBT).
Deca-BDE and HBCD are still going through the risk assessment process. Strong interest in the compounds has led to new research reports appearing every month. Recently, the compounds were found in human breast milk and in wildlife as far away as the Arctic.
The Swedish chemicals inspectorate Kemi, which is carrying out the EU environmental risk assessment of HBCD, believes there is enough evidence to classify it as a PBT compound. Meanwhile, the Environment Agency has been carrying out regular reviews of its EU risk assessment of deca-BDE.
HBCD - used in polystyrene foam and textiles - is known to meet the EU’s toxic and bioaccumulative criteria but breaks down too quickly in some tests to be classed as persistent. However recent studies suggest that, in sediment, it only degrades as far as the persistent substance 1,5,9-cyclododecatriene.
Kemi argues this means it should be classed as a PBT and is preparing a final risk assessment to this effect, which will be circulated to member states in April.
Classifying borderline PBTs should be easier under the EU’s forthcoming REACH regime for chemicals regulation, which allows substances to be classed as being PBT or of "equivalent concern", says Lars Andersson, who is in charge of the risk assessment.
The Agency completed its original assessment of deca-BDE three years ago, but is updating it in light of new information.
Recent findings include the discovery of record levels of BDE 209 - the main component of deca-BDE - in Chinese birds of prey. Concentrations of up to 12 micrograms per gram of liver tissue show its ability to bioaccumulate, say the researchers.1
In 2004, the Agency had concluded there was not enough evidence for a PBT classification, despite deca-BDE’s widespread presence and the possibility of it breaking down into more toxic and bioaccumulative substances.
An addendum to the risk assessment, compiled by the Agency in 2005, supported its original conclusions. But the EU’s Scientific Committee on Health and Environmental Risks (SCHER) recommended risk reduction measures and more regular review of the risk assessment (ENDS Report 364, pp 11-12 ).
The current review will be the Agency’s last chance to add to the huge file of data which will be passed to the European Chemicals Agency after REACH enters into force in June.
The controversy surrounding deca-BDE and the data’s complexity has prompted the Agency to seek advice from the government’s Advisory Committee on Hazardous Substances.
Documents for the committee’s next meeting show that environmental concentrations are still some way off those expected to cause harm, but raise concerns about accumulation in the environment which could be harmful and impossible to reverse.
"This lack of confidence about what constitutes a ‘safe level’ together with the potential for serious consequences… dictate a different approach to risk assessment for these substances," says the briefing paper.
The voluntary emissions control action programme (VECAP) for deca-BDE, established by the textiles industry in 2004, was expanded to HBCD in 2005 but no results are yet available. A parallel programme for polystyrene applications has also not released reduction figures.
An industry presentation on HBCD programmes at the Chemicals Stakeholder Forum in January met with a frosty reaction. Gwynne Lyons of WWF accused presenters of misrepresenting Kemi’s position on HBCD and said the reduction programme would not be appropriate if the substance was classified as PBT. Other panellists criticised the lack of baseline data.