Ratio of cord to maternal serum PCB concentrations in relation to their congener-specific physicochemical properties

Area of Science:

• Environmental Chemistry
• Toxicology
• Reproductive Health

Background:

• Polychlorinated biphenyls (PCBs) are persistent organic pollutants with known adverse health effects.
• Understanding placental transfer is crucial for assessing in utero exposure risks.
• Physicochemical properties influence the bioaccumulation and transport of environmental contaminants.

Purpose of the Study:

• To characterize the placental transfer of specific polychlorinated biphenyl (PCB) congeners.
• To investigate the relationship between human in utero PCB exposure and their physicochemical properties.
• To explore potential mechanisms of transplacental PCB transport.

Main Methods:

• Analysis of 15 PCB congeners in maternal serum and umbilical cord blood from 1134 births in eastern Slovakia (2002-2003).
• Calculation of cord serum to maternal serum (C/M) ratios for each PCB congener.
• Statistical analysis to correlate C/M ratios with physicochemical properties like KOW, molecular weight, and solubility.

Main Results:

• Significant relationships were observed between C/M ratios and various physicochemical properties, including KOW, molecular weight, and solubility.
• An inverse association was found between the logarithm of the octanol-water partition coefficient (logKOW) and the lipid-adjusted logC/M ratio (R(2)=0.039, p<0.001).
• Most evaluated physicochemical parameters were interrelated, suggesting complex transport dynamics.

Conclusions:

• Physicochemical properties, particularly lipophilicity (logKOW), significantly influence the placental transfer of PCBs.
• The findings suggest that highly lipophilic PCBs may have reduced transfer across the placenta.
• Cholesterol is proposed as a potential transplacental transporter for PCBs, warranting further investigation.