TRANSFER OF VARIOUS PCDDS AND PCDFS VIA PLACENTA AND MOTHERS MILK TO MARMOSET OFFSPRING

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDDs and PCDFs) were given subcutaneously as a defined mixture (with a composition similar to that found in incinerator fly ash) to a marmoset couple (Callithrix jacchus). At the time of treatment the female was pregnant (about 9 weeks post ovulationem) and gave birth to 3 offspring about 11 weeks later. Transfer of PCDDs and PCDFs via placenta and mother's milk was studied. Concentrations in the livers of two newborn were measured on the day of birth. In the third offspring and in the parents the concentrations were determined after a nursing period of 33 days. 1. 1. For most of the 2,3,7,8-substituted congeners transfer of PCDDs and PCDFs via placenta was very low, especially for the PCDFs. The highest transfer rate was observed for 2,3,7,8-T4CDD and 1,2,3,7,8-P5CDD. For all other compounds concentrations in hepatic tissue of the newborn were lower than 1/10 of those measured in the dam. 2. 2. Exposure of the baby to PCDDs and PCDFs via mother's milk was clearly higher than via placenta. After a 33-day nursing period hepatic concentrations in the suckled infants for some of the 2,3,7,8-substituted congeners (2,3,7,8-T4CDD, 1,2,3,7,8-P5CDD, 1,2,3,6,7,8-H6CDD; 1,2,3,7,8,9-H6CDF) were well above the corresponding concentrations in the dam. About equal concentrations in maternal and newborn liver were found for 1,2,3,4,7,8-H6CDD, 1,2,3,7,8,9-H6CDD; 2,3,4,7,8-P5CDF, 1,2,3,4,7,8-H6CDF, and 1,2,3,6,7,8-H6CDF. Clearly lower concentrations were reached in the baby's liver when compared with maternal liver for 2,3,4,6,7,8-H6CDF and all the hepta- and octa-chlorinated congeners. Subsequent to the single dose there was practically no transfer of 2,3,7,8-T4CDF and 1,2,3,7,8-P5CDF to the offspring due to the very low tissue concentrations in the maternal organism. © 1990.