Time trends and individual characteristics associated with polybrominated diphenyl ethers in breast milk samples 2006–2009 in Lower Saxony, Germany

BackgroundSince 2006 polybrominated diphenyl ether (PBDE) concentrations have been analyzed within the scope of the breast milk project conducted by the Governmental Institute of Public Health of Lower Saxony.ObjectivesTemporal trends and regional distributions of the resident population as well as the relevance of individual factors influencing PBDE concentration were to be determined.MethodsFour PBDE congeners (BDE-47, BDE-153, BDE-99, BDE-100) have been analyzed. The concentrations are fitted by linear regression models, whereby individual factors of the mother are surveyed by a standardized questionnaire.ResultsA total of 2173 samples taken between 2006 and 2009 shows an estimated total PBDE mean value of 1.68 ng/g lipid weight (l.w.). In contrast to most other studies, the proportion of BDE-153 exceeds the one of BDE-47 (median: 0.51 ng/g l.w. vs. 0.31 ng/g l.w.).BMI shows a positive correlation with BDE-47 and a negative correlation with BDE-153, both statistically significant (p < 0.001). For BDE-153, other significant factors (former breast feeding periods, birth year of the mother and country of birth) reflect also dilution effects and the time of accumulation. A decreasing temporal trend is observed for BDE-47 but not for BDE-153.ConclusionsThe correlation patterns, the temporal trends and the various influencing factors may reflect differences in exposure sources and/or metabolism between the major congeners BDE-47 and BDE-153. Therefore it seems to be necessary to discuss the concentrations of BDE-47 and BDE-153 separately as leading indicators instead of using a total PBDE.