Placental transfer of persistent organic pollutants and feasibility using the placenta as a non-invasive biomonitoring matrix.

The placenta is a crucial organ for the supply of oxygen and nutritional elements from mother to fetus. Several studies have reported evidence of the placental transfer of persistent organic pollutants (POPs). Despite the importance of prenatal exposure to POPs, the transport process of POPs via the human placenta is not well understood. To investigate the transport processes of these contaminants and to assess the feasibility of the placenta as a non-invasive biological matrix, we measured 19 polychlorinated biphenyls (PCBs), 18 organochlorine pesticides (OCPs), and 24 polybrominated diphenyl ethers (PBDEs) in placenta tissues. The total concentrations of PCBs, OCPs, and PBDEs in placental tissues ranged from 0.36 to 75.2 (median: 5.85) ng/g lipid wt, 1.37 to 250 (63.5) ng/g lipid wt, and 1.21 to 427 (11.7) ng/g lipid wt, respectively. The BDE 209 concentrations were higher than those reported in previous studies presumably because of the high consumption of deca-BDE technical mixtures in Korea. The concentrations of all of the POPs in placental tissues correlated significantly with each other, but BDE 209 concentration did not correlate with that of any other contaminants possibly because of different exposure sources and kinetics. Maternal age, body mass index, and parity were contributors to the accumulation of several POPs in the placenta. Partitioning ratios between maternal blood-placenta-cord blood showed that lower molecular-weight and hydrophobic POPs were preferentially transported from maternal blood to the placenta and that higher molecular-weight and hydrophobic contaminants tended to remain in placental tissues. Regression analysis showed significant relationships between the POP concentrations in multiple biological matrices such as maternal blood, placenta, cord blood, and meconium. These relationships suggest that the placenta can be used as a non-invasive matrix for biomonitoring prenatal exposure to several POPs.