Prenatal and postnatal exposure risk assessment of chlorinated paraffins in mothers and neonates: Occurrence, congener profile, and transfer behavior

Gestation and lactation are very sensitive and vulnerable stages for human growth and development. During these two periods, short-chain chlorinated paraffins (SCCPs) and medium-chain chlorinated paraffins (MCCPs) can be transported to neonates via transplacental and breastfeeding transfers, and eventually posing potential adverse effects to neonates. Up to date, no simultaneous investigation of prenatal and postnatal exposure of CPs is reported. To bridge this knowledge gap, we have analyzed SCCPs and MCCPs in 20 complete sets of maternal serum, umbilical cord serum, placenta, and breast milk. The levels of both Sigma SCCP and Sigma MCCP followed the order of maternal serum > breast milk > cord serum > placenta. The breastfeeding transfer ratios (R-BM approximate to 1.0) of CPs were greater than the corresponding transplacental transfer ratios (R-CM < 1.0), demonstrating the higher transport of CPs during the lactation period. The placental retention/or accumulation ratios (R-PM) showed that CPs were effectively retained by the placental barrier. Furthermore, the total exposure amount of SCCPs and MCCPs during the lactation period was > 100 times higher than the gestation exposure amounts. This study helps to better understand the prenatal and postnatal exposure of CPs and provides a solid basis for accurate human health risk assessment of CPs.