THE OLFACTORY SYSTEM AS A PORTAL OF ENTRY FOR AIRBORNE POLYCHLORINATED-BIPHENYLS (PCBS) TO THE BRAIN

Ferrets, mammalian carnivores, kept in an indoor enclosure were contin uously exposed to low concentrations of polychlorinated biphenyls (PCB s) in the ambient air for 5 years. After that time PCB concentrations were quantified in the olfactory bulbs and in the remaining brain, adi pose tissue and liver. The results revealed unexpectedly high PCB conc entrations in the olfactory bulbs, surpassing those in the remaining b rain and the peripheral tissues. The PCB congener pattern in the olfac tory bulbs resembled that found in the ambient air and the less chlori nated volatile PCBs were found in higher concentrations. We, therefore , assume that airborne PCBs enter directly via the olfactory system an d are transported through the axons to the olfactory bulbs where they accumulate.