title: Depuration of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) in breast milk from California first-time mothers (primiparae).
abstract: BACKGROUND
  Little is known about the rates of loss (depuration) of polybrominated diphenyl ethers (PBDEs) and polychlorinated biphenyls (PCBs) from mothers during lactation. Depuration rates affect infant exposure to chemicals during breast-feeding, and fetal and lactational transfers during subsequent pregnancies.
  
  
  OBJECTIVE
  Our objective in this study was to estimate depuration rates of PBDEs and PCBs using serial samples of breast milk.
  
  
  METHODS
  Nine first-time mothers (primiparae) each collected samples at 4, 6, 8, 12, 16, 20, and 24 weeks after birth. Nine additional primiparae each collected two samples at varying time intervals (18 to > 85 weeks after birth). Analytical precision was assessed to evaluate the accuracy of measured monthly percentage declines in PBDEs and PCBs.
  
  
  RESULTS
  The four major PBDE congeners decreased 2 or 3% +/- 1% per month over the 6-month period. These decreases were consistent over a 50-fold range (21-1,330 ng/g lipid weight) of initial PBDE concentrations in breast milk. The change in PCB-153 ranged from + 0.3% to -0.6% per month, with heterogeneous slopes and greater intraindividual variability. PBDE and PCB concentrations declined 1% per month over longer periods (up to 136 weeks).
  
  
  CONCLUSIONS
  Our data indicate that PBDEs and PCBs are not substantially (4-18%) reduced in primiparae after 6 months of breast-feeding. Consequently, the fetal and lactational exposures for a second child may not be markedly lower than those for the first. Participants were volunteers from a larger study population (n = 82), and were typical in their PBDE/PCB levels and in many demographic and lifestyle factors. These similarities suggest that our results may have broader applicability.
authors.affiliation: Environmental Chemistry Laboratory, California Department of Toxic Substances Control, Berkeley, California, USA. khooper@dtsc.ca.gov
authors.forename: Kim
authors.initials: K
authors.lastname: Hooper
authors.forename: Jianwen
authors.initials: J
authors.lastname: She
authors.forename: Margaret
authors.initials: M
authors.lastname: Sharp
authors.forename: Joan
authors.initials: J
authors.lastname: Chow
authors.forename: Nicholas
authors.initials: N
authors.lastname: Jewell
authors.forename: Rosanne
authors.initials: R
authors.lastname: Gephart
authors.forename: Arthur
authors.initials: A
authors.lastname: Holden
mesh_terms: D000328:Adult; D002140:California; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000378:metabolism*; D005260:Female; D006801:Humans; D007774:Lactation / Q000378:metabolism*; D018811:Maternal Exposure; D008895:Milk, Human / Q000737:chemistry*; D009035:Mothers; D010647:Phenyl Ethers / Q000378:metabolism*; D011075:Polybrominated Biphenyls / Q000378:metabolism*; D011078:Polychlorinated Biphenyls / Q000378:metabolism*