What are brominated flame retardants?

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The Norwegian Institute for Air Research (NILU) has developed methods for analysis and undertakes several projects to structure the know-ledge on Brominated flame retardants (BFRs) in the environment.

Brominated flame retardants (BFRs) are a group of organic compounds used as additives to electronic equipments, furnitures, textiles, plastics and isolation materials for their flame retardant properties.

The most commonly used BFRs are the brominated diphenylethers (PBDE), hexabromocyclododecane (HBCD) and tetrabromobisphenol-A (TBBPA) with a world annual use of approximately 150 000 ton. The annual use of BFRs in Norway is approximately 300 ton.

The start of a fire can occur spontaneously or result from an external source, such as a flame. It is generally assumed that BFRs, during strong heat, liberate hydrogen bromide, which react with the free radicals responsible for the propagation of combustion and suppress it. The decomposition of the bromined flame retardant will occur approximately 50ºC below that of the polymer.

BFR as environmental contaminants

The extensive use of BFRs and their structural similarity to the polychlorinated biphenyls (PCBs) and dioxins make them potential environmental hazards. The BFRs may leak into the environment from products containing the substances, and be spread by atmospheric and aquatic transport. The BFRs are persistent and bioaccumulate in the biota. BFRs are even found in considerable amounts in mother’s milk.

What are brominated flame retardants?
The highest concentrations are found in animals which are at the top of the trophic levels and which have based their nourishment on food with marine or limnic origin. Screening of the levels of Penta-BDEs in Norwegian lakes revealed that fish from lake Mjøsa have very high levels of these compounds compared to other lakes. These findings indicate that lake Mjøsa is exposed to local sources of pollution.
What are brominated flame retardants?

Are brominated flame retardants toxic?

BFRs have a low acute toxicity, but are suspected to be harmful during long term exposure. The toxic effects resemble the toxic effects of the PCBs, and include effects on immune-, nervous- and endocrine system.

Infants exposed to environmental contaminants during their mother’s pregnancy are especially vulnerable since they are not yet fully developed. For the same reasons the findings of environmental contaminants in mother’s milk is of concern, although the advantage of nursing is not questioned.

Animals, which periodically suffer from starvation, are also vulnerable since environmental toxins may then redistribute from the fat deposits to blood and brain. Although the toxic effects of BFRs are claimed to be less than those observed for the PCBs, they will contribute as an additional load to the biota together with other types of pollution.

What are brominated flame retardants?

Research at NILU

To achieve more knowledge, NILU has several on-going projects to strengthen the national competence concerning sources, spread, exposure and toxic effects of environmental contaminants such as the BFRs. On the basis of findings in the environment, the Norwegian pollution authorities have now implemented actions to reduce the release and industrial use of the most toxic and environmental persistent BFRs.

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