Time course of PCDD/PCDF/PCB concentrations in breast-feeding mothers and their infants.

PCDD/PCDF/PCB concentrations were measured in samples from four mothers (at delivery and during lactation) and their infants (at birth and the end of first year of life). For two of these mothers it was the second delivery and breast-feeding period, and additional data were available from first lactation period and the first-born infant at the age of 11 to 12 months. Five of the six infants were fully breast-fed for at least 17 weeks. In four of them a distinct PCDD/PCDF/PCB accumulation was observed at the end of the first year of life: concentrations in blood fat were 1.5 to 3.6 times higher than maternal levels measured at the same time. Due to decreasing maternal body burdens during lactation, PCDD/PCDF concentrations at 11 to 12 months of life were only about half as high in the second infant as in the first one at the same age. During second pregnancy, no important change of the concentrations was observed in maternal blood.