INTAKE, FECAL EXCRETION, AND BODY BURDEN OF POLYCHLORINATED DIBENZO-P-DIOXINS AND DIBENZOFURANS IN BREAST-FED AND FORMULA-FED INFANTS

To assess toxicokinetics of polychlorinated dibenzo;p-dioxins (PCDDs) and dibenzofurans (PCDFs), oral intake and fecal excretion were measur ed in two breast-fed infants and one formula-fed infant during the Ist y of life. The intake of these compounds was up to 50 times higher in the breast-fed infants. In these children, fecal excretion of the mai n tetra- to hexachlorinated congeners was less than 9% of the intake a t age of 1 and 5 mo, indicating almost complete intestinal absorption during breast-feeding, In contrast, distinctly higher fecal excretion rates were observed for the hepta- and octachlorinated compounds. Desp ite much lower PCDD/PCDF intake after weaning, concentrations in stool fat did not decrease substantially. We conclude that concentrations i n fecal fat more or less reflect those in body fat. Additionally, PCDD /PCDF concentrations were measured in blood fat of all infants (and in a second formula-fed baby) at the age of 11 mo. International toxicit y equivalent (I-TEq) concentrations in the formula-fed infants were le ss than 25% of maternal values and about 10 times lower than in the in fants breast-fed for 6-7 mo. In the latter, a distinct accumulation wa s found for the tetra- to hexachlorinated congeners compared with mate rnal concentrations. We conclude that accumulation of PCDDs and PCDFs in infants is as high as expected on the basis of intake data and assu ming complete absorption and negligible elimination during the Ist y o f life.