The Belgian PCB and dioxin incident of January-June 1999: Exposure data and potential impact on health

In January 1999, 500 tons of feed contaminated with approximately 50 kg of polychlorinated biphenyls (PCBs) and 1 g of dioxins were distributed to ani mal farms in Belgium, and to a lesser extent in the Netherlands, France, an d Germany. This study was based on 20,491 samples collected in the database of the Belgian federal ministries from animal feed, cattle, pork, poultry, eggs, milt, and various fat-containing food items analyzed for their PCB a nd/or dioxin content. Dioxin measurements showed a clear predominance of po lychlorinated dibenzofuran over polychlorinated dibenzodioxin congeners, a dioxin/PCB ratio of approximately 1:50,000 and a PCB fingerprint resembling that of an Aroclor mixture, thus confirming contamination by transformer o il rather than by other environmental sources. In this case the PCBs contri bute significantly more to toxic equivalents (TEQ) than dioxins. The respec tive means +/- SDs and the maximum concentrations of dioxin (expressed in T EQ) and PCB obsrrved per gram of fat in contaminated food were 170.3 +/- 48 7.7 pg, 2613.4 pg, 240.7 +/- 2036.9 ng, and 51059.0 ng in chicken; 1.9 +/- 0.8 pg, 4.3 pg, 34.2 +/- 30.5 ng, and 314.0 ng in milli; and 32.0 +/- 104.4 pg, 713.3 pg, 392.7 +/- 2883.5 ng, and 46000.0 ng in eggs. Assuming that a s a consequence of this incident between 10 and 15 kg PCBs and from 200 to 300 mg dioxins were ingested by 10 million Belgians, the mean intake per ki logram of body weighs is calculated to maximally 25,000 ng PCBs and 500 pg international TEQ dioxins. Estimates of the total number of cancers resulti ng: from this incident range between 40 and 8,000. Neurotoxic and behaviora l effects in neonates are also to be expected but cannot be quantified. Bec ause food items differed widely (more than 50-fold) in the ratio of PCBs to dioxins, other significant sources of contamination and a high background contamination are likely to contribute substantially to the exposure of the Belgian population.