Polybrominated diphenyl ethers (PBDEs) in US computers and domestic carpet vacuuming:: Possible sources of human exposure

Polybrominated diphenyl ethers (PBDEs), a type of brominated flame retardant chemically and toxicologically similar to polychlorinated biphenyls (PCBs), are a class of emerging environmental and human contaminants. They have recently been detected in U.S. milk, blood, and food at the highest levels in the world. This pilot study was undertaken with the aim of determining levels of PBDE in the U.S. indoor environment, to assess the potential exposure to PBDEs from computer surfaces and carpets. Food of animal origin is the usual source of polychlorinated dibenzo-p-dioxin (PCDD), polychlorinated dibenzofurans (PCDF), and PCBs in humans, but there may also be environmental sources for intake of PBDEs. It was also our aim to characterize the PBDE congener profile in these indoor environmental samples. Four computer wipe samples and 9 domestic vacuum-sweeping samples were analyzed for 13 PBDE congeners, PBDEs 17 (2,2',4), 28 (2,4,4'), 47 (2,2',4,4'), 66 (2,3',4,4'), 77 (3,3',4,4'), 85 (2,2',3,4,4'), 99 (2,2'4,4',5), 100 (2,2',4,4',6), 138 (2,2',3,4,4',5'), 153 (2,2',4,4',5,5'), 154 (2,2',4,4',5',6), 183 (2,2',3,4,4',5,6'), and 209 (2,2',3,3',4,4',5,5',6,6'). All samples tested positive for PBDEs. PBDE 209 was the dominant congener in all 4 computer wipe samples and in 7 out of the 9 vacuum dust samples. The congener profiles observed in this study varied considerably, a finding that has been observed previously. However these congener profiles differ from the pattern seen in U.S. human milk, human blood and in food, where PBDEs 47 and 99 predominate.