The Belgian PCB/dioxin incident: A critical review of health risks evaluations

The Belgian PCB/dioxin incident is a food contamination that occurred in Belgium in January 1999 when a tank of recycled fats used to produce animal feeds was accidentally contaminated by approximately 100 L of polychlorinated biphenyl (PCB) oil containing 50 kg PCBs expressed as the sum of the seven markers, I g (TEQ) dioxins (PCDD/Fs) and 2 g toxic equivalent (TEQ) dioxin-like PCBs. The incident was discovered when a poultry poisoning resembling the classic chick edema disease broke out in several farms that had received contaminated feeds. The delay in making public this incident resulted in a major political and food crisis and caused much concern in the population. We review here the health risk evaluations that were made after this incident and we assess the likelihood of the different scenarios by taking into account recent data on the real scale of the contamination and on the dioxin body burden of the general population in Belgium. These new data confirm that the incident was too limited in time and in scale to have increased the PCB/dioxin body burden of the general population at large, a conclusion supported by a survey of dioxin levels in blood conducted at the end of 1999. Only farmers in poultry farms affected by the incident (about 30 farms) and having regularly consumed their own products could have increased their PCB/dioxin body burden. It is unlikely, however, that these farmers could have increased their PCB/dioxin body burden above levels prevailing in the 1980s or now found in communities regularly consuming seafood.