PBDE levels in breast milk are decreasing in California

- We found significant declines in PBDE and PCB levels between 2003-2005 and 2009-2012 in breast milk of California women.
- We found highly correlated levels and identical congener profiles in breast milk, maternal, and cord blood.
- We confirmed that PBDE levels are decreasing in California after PBDE ban.
- Almost 30% of breastfed babies would be exposed to BDE-47 above the USEPA RfD.

To assess the efficacy of the bans in reducing PBDE levels, we recruited 67 California first time mothers (sampled during 2009-2012) and collected cord blood at birth (n = 31), breast milk (n = 66) and maternal blood (n = 65) at 3-8 weeks postpartum. Using the same sample extraction procedures and analytical instrumentation method (GC-HRMS), we compared PBDE as well as PCB levels in these breast milk samples to those from our previous study (n = 82, sampled during 2003-2005) and found that the sum of PBDEs over the ∼7 year course declined by 39% (GeoMean = 67.8 ng/g lipid in 2003-2005; 41.5 ng/g lipid in 2009-2012) and that the sum of PCBs declined by 36% (GeoMean = 71.6 ng/g lipid in 2003-2005; 45.7 ng/g lipid in 2009-2012). This supports our earlier finding of a PBDE decline (39%) in blood. We also found that the PBDE concentrations and congener profiles were similar in breast milk and their matched maternal/cord blood: BDE-47 was the dominant congener, followed by BDE-153, -99, and -100. Similar levels and congener profiles of PBDEs in these matrices suggest that they are at equilibrium. Therefore, we propose that maternal serum levels may be used to predict an infant's daily dose of PBDE exposure from breastfeeding when breast milk levels are not available. In addition, our study confirmed that breastfeeding babies are still exposed to high levels of PBDEs, even though PBDE levels are decreasing.

PBDE levels (mean and standard error, ng/g lipid) decreased in CA breast milk in 2009-2012 (red bars) compared to 2003-2005 levels (blue bars). *** = p < 0.05, p values were determined from one tailed t test.186