Abstract

In January 1999, 50 kg polychlorinated biphenyls (PCBs) contaminated with 1 g dioxins were accidentally added to a stock of recycled fat used for the production of 500 tonnes animal feed in Belgium. Although signs of poultry poisoning were noticed by February 1999, the extent of the contamination was publicly announced only in May 1999, when it appeared that more than 2500 poultry and pig farms could have been involved. This has resulted in a major food crisis, known worldwide as the "Belgian PCB/dioxin crisis". The crisis was resolved by the implementation of a large food monitoring program for the seven PCB markers (PCBs 28, 52, 101, 118, 138, 153 and 180). When PCB concentrations exceeded the tolerance levels of 100, 200 or 1000 ng/g fat for milk, meat or animal feed, respectively, the 17 toxic polychlorinated dibenzodioxins and furans (PCDD/Fs) congeners were also determined. By December 1999, more than 55,000 PCB and 500 dioxin analyses were already done by Belgian and international laboratories. The highest concentrations of PCBs and dioxins and the highest percentage of affected animals were found in poultry. Several important consequences of the food crisis were: (1) the introduction in 1999 of norms for PCBs in feedstuffs and food in Belgium followed by the introduction in 2002 of European harmonized norms for PCDD/Fs in animal feed and food of animal origin; (2) the systematic national monitoring of food of animal origin; and (3) the creation of the Federal Agency for Food Safety in Belgium. The human health risk following this major incident was assessed with contradictory results. It was suggested that, since only a limited proportion of the food chain was contaminated, it is unlikely that adverse effects were inflicted in the Belgian population. However, another assessment suggests that neurotoxic and behavioural effects in neonates, together with an increase in the number of cancers, may be observed.