Polybrominated diphenyl ethers in UK human milk: Implications for infant exposure and relationship to external exposure

Fourteen tri-deca polybrominated diphenyl ethers (PBDEs) were investigated in 35 human milk samples from Birmingham, UK. While none of the hepta-nona BDEs (the main components of the octaBDE technical mixture) was above the limit of quantitation (LOQ); BDE-47 (average concentration=3.3ngg lipid weight (lw)) was quantified in all samples contributing 34-74% to σtri-hexa BDEs (the principal constituents of the pentaBDE commercial formulation). BDE-209 (the main congener in the decaBDE formulation) was present above the LOQ in 69% of samples (average concentration=0.31ngg lw). Concentrations of σtri-hexa BDEs ranged from 0.2 to 26ngg lw with concentrations of BDE-47>BDE-153>BDE-99. While concentrations of σtri-hexa BDEs in this study (average=5.95ngg lw) were at the high end of those reported from other European countries, concentrations of BDE-209 were lower than those reported in human milk from other countries. The average exposure of a UK nursing infant to σtri-hexa BDEs (35ng (kg bw)day) via breast milk exceeded the upper-bound dietary intakes of both UK adults and toddlers. Using a simple one compartment pharmacokinetic model, PBDE intakes of UK adults via inhalation, diet and dust ingestion were converted to predicted body burdens. Predictions compared well with those observed for σtri-hexa BDEs and BDE-209 in breast milk.