Polychlorinated biphenyls (PCBs) are toxic, persistent and bioaccumulative. Despite their worldwide ban in 2004, consumption of bovine products accounts for >70% of the total exposure. This is of concern since 50% Europeans exceed the tolerable weekly intake, but occasionally results aso in herd/product destruction given an accidental contamination. To improve chemical safety, the PCB-transfer from feed to cows/calves over the end of gestation and full lactation was examined. Twelve Simmental cow-calf pairs were monitored from 113 days before parturition until 288 days in milk (DIM). Calves were fed milk of their respective mother. Four cows received control grass silage and 8 a PCB-loaded soil-grass silage mix. After 164 DIM, latter was divided into 4 exposed and 4 decontaminated. The PCB kinetics were analyzed via HRGC-MS. The exposed diet had a 6 to 11-higher PCB concentration compared to the control diet, resulting in a 4 to 8-fold higher milk level. Switching exposed cows to clean feed resulted in a 2-phased exponential decline of the milk PCB concentration. Calf serum was 2 to 3-fold higher in PCB concentrations compared to cow serum. These results will help to assess the predicitive capability of physiological-based toxicokinetic mo dels, to ensure their use in risk assessment and management.
