Measurements of selected brominated flame retardants in nursing women: implications for human exposure

Abstract

We have examined several emerging brominated flame retardants (BFRs) including 2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate (TBB), bis(2-ethylhexyl) tetrabromophthalate (TBPH), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), 4,5,6,7-tetrabromo-1,1,3-trimethyl-3-(2,3,4,5-tetrabromophenyl)-indane (OBIND), and decabromodiphenyl ethane (DBDPE) in paired human maternal serum (n = 102) and breast milk (n = 105) collected in 2008-2009 in the Sherbrooke region in Canada. Three legacy BFRs were also included in the study for comparison: decabromobiphenyl (BB-209), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), and 2,2',4,4',5,5'-hexabromodiphenyl ethers (BDE-153). TBB, BB-153, and BDE-153 had detection frequencies greater than 55% in both serum and milk samples. Their lipid weight (lw) adjusted median concentrations (ng g(-1) lw) in serum and milk were 1.6 and 0.41 for TBB, 0.48 and 0.31 for BB-153, and 1.5 and 4.4 for BDE-153, respectively. The detection frequencies for the other BFRs measured in serum and milk were 16.7% and 32.4% for TBPH, 3.9% and 0.0% for BTBPE, 2.0% and 0.0% for BB-209, 9.8% and 1.0% for OBIND, and 5.9% and 8.6% for DBDPE. The ratio of TBB over the sum of TBB and TBPH (fTBB) in serum (0.23) was lower than that in milk (0.46), indicating TBB has a larger tendency than TBPH to be redistributed from blood to milk. Overall, these data confirm the presence of non-PBDE BFRs in humans, and the need to better understand their sources, routes of exposure, and potential human health effects.

Figure 1

Molecular structures, formulas, molecular weight (M.W.) and octanol–water partition coefficients (K_ow) of brominated flame retardants measured in this study. TBB = 2-ethyl-1-hexyl 2,3,4,5-tetrabromobenzoate, TBPH = bis(2-ethylhexyl)tetrabromophthalate, BTBPE = 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), BB-209 = decabromobiphenyl, OBIND = 4,5,6,7-tetrabromo-1,1,3-trimethyl-3-(2,3,4,5-tetrabromophenyl)-indane, DBDPE = decabromodiphenyl ethane, BB-153 = 2,2′,4,4′,5,5′-hexabromobiphenyl, and BDE-153 = 2,2′,4,4′,5,5′-hexabromodiphenyl ethers.

Figure 2

Scatter plot of BDE-153 levels in 46 paired serum and milk samples in which BDE-153 was detected in both matrices.