Elucidation of environmental and human emission by PBDDs/DFs and PXDDs/DFs in Japan

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Polybrominated diphenyl ethers (PBDEs) and tetrabromobisphenol A (TBBPA) are used in large quantities as brominated flame-retardants (BFRs) to reduce the risk of fire in a wide range of manufacture products such as computers, furnitures, textiles and automobiles. Inaddition, there is sufficient evidence that the above similar process or incineration of consumer products containing such flame-retardant chemicals results in the formation of polybrominated dibenzo-p-dioxins/furans (PBDD/DFs) and monobromo-polychlorinated dibenzo-p-dioxins/furans (PXDD/DFs). These chemicals, as well as the BFRs, have been found to occur throughout the environment. And the intake of these contaminants from food, air and water is suspected to be the primary route of human. The levels of PCDDs/DFs, PXDDs/DFs and PBDDs/DFs in the sediments from Setouchi-Sea were compared. Almost was PCDDs/DFs, showing the levels of PCDDs/DFs (1.3 - 13 ng/gd.w)>PBDDs/DFs (15 - 16,000 pg/g d.w.)>PXDDs/DFs (1.0 - 90 pg/g d.w ). Especially, extreme high pollution by PBDDs /DFs was observed in the sample of Mizushima, and high concentrations of TeBDD/DF, PeBDD and HxBDD as 2,3,7,8-substituted isomer were detected.The TEQ levels of PCDDs/DFs, PXDDs/DFs and PBDDs/DFs in the mixed breast milk, cow's milk and powdered milk were investigated. Average TEQ concentration (20.3 pg TEQ/g lipid) in breast samples from primiparae was over two-fold against that (10.8 pg TEQ/g lipid) from multiparae. As an extremely interesting phenomenon, it was recognized that the ratio of PXDDs/DF for PCDDs/DFs calculated as TEQ concentration ranged between 4 and 46 %.