Investigating Intergenerational Differences in Human PCB Exposure due to Variable Emissions and Reproductive Behaviors

BACKGROUND: Reproductive behaviors-such as age of childbearing, parity, and breast-feeding prevalence-have changed over the same historical time period as emissions of polychlorinated biphenyls (PCB) and may produce intergenerational differences in human PCB exposure. OBJECTIVES: Our goal in this study was to estimate prenatal, post-natal, and lifetime PCB exposures for women at different ages according to year of birth, and to evaluate the impact of reproductive characteristics on intergenerational differences in exposure. METHODS: We used the time-variant mechanistic model CoZMoMAN to calculate human bio-accumulation of PCBs, assuming both hypothetical constant and realistic time-variant emissions. RESULTS: Although exposure primarily depends on when an individual was born relative to the emission history of PCBs, reproductive behaviors can have a significant impact. Our model suggests that a mother's reproductive history has a greater influence on the prenatal and post-natal exposures of her children than it does on her own cumulative lifetime exposure. In particular, a child's birth order appears to have a strong influence on their prenatal exposure, whereas post-natal exposure is determined by the type of milk (formula or breast milk) fed to the infant. CONCLUSIONS: Prenatal PCB exposure appears to be delayed relative to the time of PCB emissions, particularly among those born after the PCB production phaseout. Consequently, the health repercussions of environmental PCBs can be expected to persist for several decades, despite bans on their production for > 40 years.