Brominated flame retardants in matched serum samples from Swedish first-time mothers and their toddlers.

Tri-decabrominated diphenyl ethers and 21 other flame retardants were determined in matched serum samples from 24 Swedish mothers (Uppsala county) and their toddlers (11-15 months of age). The median concentrations of individual polybrominated diphenyl ethers (PBDEs) ranged from 0.036 to 0.95 ng/g lipid in mothers and from 0.057 to 1.5 ng/g lipid in toddlers. BDE-209 was detected in all but one sample. BDE-153 was the predominant congener in the mothers while in toddlers, BDE-209 was found in the highest concentrations. The levels of BDE-47, -100, -207, -208, and -209 in toddlers were significantly higher (p < 0.05) than those in their mothers. Dechlorane Plus (anti- and syn-) and α- and β-tetrabromoethylcyclohexane were detected in a few (2-4) serum samples from both mothers and toddlers. This study also reports concentrations of α-HBCD and eight emerging brominated flame retardants (EBFRs) in the standard reference material serum (SRM 1958, NIST). Lack of correlations between the matched serum samples indicate different exposure routes for octa-decaBDEs in mothers versus toddlers. Congener-to-congener correlations within the mother or toddler cohorts suggest diet as an important exposure pathway for tetra-nonaBDEs for mothers, breastfeeding as a predominant exposure pathway for tetra-hexaBDEs, and dust for octa-decaBDEs for toddlers.