A review on sources of brominated flame retardants and routes of human exposure with emphasis on polybrominated diphenyl ethers

The presence of brominated flame retardants (BFRs) in various environmental matrices, including humans, has been well documented. Increasing levels of these emerging contaminants in various environmental compartments suggest the wide application of these chemicals in products of everyday use. The release of BFRs from treated products is generally believed to be the major source of these contaminants into the environment, particularly in indoor environments. The sources and pathways through which BFRs enter the human system are evaluated in this paper. Human exposure via consumption of contaminated food and water, inhalation and ingestion of dust, as well as dermal absorption, are important pathways for these contaminants. Consumption of fatty foods especially fish, meat, dairy products as well as human milk constitute important routes for human exposure to these contaminants. Although brominated diphenyl ether (BDE) 209 has been found to be less bioaccumulative due to its high molecular weight, its dominance in indoor dust samples could be responsible for its detection in most human tissues investigated. BDE 47 is the most dominant polybrominated diphenyl ether (PBDE) congener found in human tissues. Regional differences in BFR levels in various environmental and biological matrices reflect their consumption patterns with higher levels mostly reported in the North American environments than in other regions of the world.