(Poly)brominated diphenylethers (PBDEs) are a group of chemicals with similar properties that are used as mixtures in industrial applications. There are a total of 209 individual chemicals ('congeners') within the family of PBDEs. Three main types can be distinguished, depending on how many atoms of bromine are present in each molecule: Penta-BDE (5 bromine atoms), Octa-BDE (8 bromine atoms) and Deca- (10 bromine atoms). These three substances are the only PBDEs commercially available.
Pentabromodiphenylether (Penta-BDE) is itself a mixture of related substances, which contain four to six atoms of bromine per molecule. The commercial grade is found as a dense amber thick oily liquid or semi-solid that decomposes when heated above 200 0C. It is completely non-flammable and is used as a flame retardant. It is insoluble in water but mixes with paraffin oil and other organic solvents. It is almost completely non volatile.
Penta-BDE is used mainly as flame retardant in flexible polyurethane foam for furniture and upholstery in the USA, and to a lesser extent in rigid plastics and adhesives, and may make up 10% by weight of the finished product. Manufacture of Penta-BDE in the EU ceased in 1997 and usage rates have fallen steadily in the past decade. Octa-BDE and Deca-BDE are used in conjunction with antimony trioxide as flame retardants in rigid plastics used in making cars and consumer goods such as electrical appliances. In the European Union a ban on the marketing and use of Penta-BDE and Octa-BDE in all applications will be effective from 15 August 2004 onwards.
PBDEs may be released into the environment during the manufacture of the chemical itself, incorporation into plastic products (mostly polyurethane foam), processing of the foam into finished articles, release during the lifetime of the article and finally disposal in landfill or incineration. In general small amounts only of the substance are released because of its very low volatility and low water solubility. Dust produced from foam products is usually the main form of release from products. Penta-BDE has also been measured in animal tissue, water and sediment far from sources of release, giving concern over the possible global impact of releases.
Impacts on human health and environment
Excessive exposure to Penta-BDE may affect the liver of humans. Penta-BDE is highly toxic to aquatic animals and may cause long-term adverse effects to the aquatic environment. Penta-BDE is highly persistent and bioaccumulative. Effects on the growth and reproduction of aquatic animals have been reported. Aquatic toxicity and bioaccumulation potential of PBDEs decrease with increasing bromination, therefore it is unlikely that Deca-PBDE will show any toxic effects to invertebrates at concentrations below its solubility limit. PBDEs may decompose in fires to produce highly toxic brominated chemicals.
PBDEs are listed as priority substances, Penta-BDE even as a priority hazardous substance in the Water Framework Directive.
Penta-, Octa- and Deca-BDE are all priority substances under Regulation 793/93. The risk assessment reports on all 3 substances can be downloaded from http://ecb.jrc.it/existing-chemicals/.
Emission to water reporting threshold: 1 kg/year
Data source: European Pollutant Emission Register