Polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from the Pacific Northwest

Breast milk samples from 40 first-time mothers from the Pacific Northwest of the US and Canada were analyzed for polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs). Total PBDEs (∑PBDEs), calculated by summing values for the 12 PBDEs congeners analyzed, ranged from 6 to 321 ppb (lipid weight) (mean = 96 ppb; median = 50 ppb). In ∼40% of the women (15/40), ∑PBDEs > 100 ppb lw in their milk, and four samples had levels >250 ppb lw. PBDE 47 was the dominant congener in most samples, whereas PBDE 153 was predominant in a few (3/40). ∑PCBs were calculated by summing values for the 82 PCB congeners analyzed, and ranged from 49 to 415 ppb (lipid weight) (mean = 147 ppb; median = 126 ppb). ∼30% of the mothers (13/40) have ∑PBDEs > ∑PCBs in their milk samples, and ∼65% (25/40) have BDE 47 > PCB 153 in breast milk samples, with BDE 47 averaging 3-fold greater levels than PCB 153. Clearly, the lower brominated PBDEs are surpassing PCBs as a major environmental concern in North America, and are likely affecting significant portions of the populations in these regions. PBDEs have become a major persistent organic pollutant. However, there are no positive correlations between levels of ∑PBDEs and ∑PCBs, or between levels of PBDE 47 and PCB 153, suggesting there may be some differences in exposure pathways for PBDEs and PCBs in humans.