THE INTERPRETATION OF ITALIAN BREAST MILK MONITORING OF DIOXIN-LIKE AND NON-DIOXIN LIKE POLLUTANTS WITH A PBPK MODEL INTEGRATING A NOVEL APPROACH TO DESCRIBE PRE- AND POSTNATAL MOTHER/CHILD TRANSFER

Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are widespread environmental contaminants. They enter the human body mainly with food and because of lipophilic character they accumulate in fatty tissues. Knowledge about the intake and body burden of PCDD/Fs and PCBs in a population helps to focus efforts to diminish population exposure to these compounds. This study aimed to interpret the results from a recent biomonitoring study of PCDD/Fs and PCBs in breast milk of Italian non-occupationally exposed mothers by a PBPK model of mother and infant. Measurements included detection of 2,3,7,8 substituted polychlorinated dibenzo-p-dioxins, polychlorinated dibenzofurans and polychlorinated biphenyls and estimation of the dietary intake of these pollutants by lactating infants. The modelling part was focused on one PCB congener – PCB 153. Here, reverse dosimetry was performed to estimate mother external dose, and forward dosimetry to predict tissue concentrations in mother and infant daily intake. The modeling outcomes provided an historical perspective on the changing exposure of the Italian population to PCB-153. They realistically reflect the evolution of daily intake during the mother’s life, and evolution of blood contamination. At the same time it was proved that breast milk is good biomarker of historical exposure and in combination with PBPK modeling can be used to characterize prospectively and retrospectively, internal and external exposures. So far, this is the first study which reconstructed the dynamic exposure for specific population. Results of this work can dramatically change the way to perform modeling for substances such us POPs, similar trends to PCBs is observed for PCDD/Fs , DDT, HCB etc.