What consequences did the Chernobyl nuclear disaster have for Belgium?

Answer

Dear Tim

On April 26, 1986, reactor unit 4 exploded in Chernobyl. This was the worst accident in the history of the peaceful uses of nuclear energy.
About the origin of the accident, I would like to refer you to another question that was previously answered via the IHEV platform.

In the period after the Chernobyl accident, the Belgian population was exposed to radioactive radiation in various ways. The main exposure was caused by the external radiation from the radioactive materials that ended up on the ground, by inhalation of contaminated dust and by eating contaminated food. In Belgium in 1986 the distribution of the infection was dependent on the weather conditions. In places where it rained, air activity settled on the ground and formed a greater surface contamination than in places where it remained dry. In the SCK•CEN publication ‘Chernobyl, 25 years later’ you will find a map of Belgium with therefore the measured and calculated surface activity for iodine-131, cesium-134 and cesium-137, the main isotopes released from this accident.

In Mol, which is located in the most contaminated part, SCK•CEN made a large number of measurements that were taken as a reference for Belgium. In addition to environmental radiation, radioactive iodine and cesium were also measured in air dust, grass, leafy vegetables, milk and meat. In May 1986, numerous measurements on various food crops showed that contamination levels were well below current standards. Certain vegetables whose leaves have been directly exposed to atmospheric deposition have shown maximum contamination levels for iodine-131 of 400 Bq/kg for lamb’s lettuce, 300 Bq/kg for lettuce and between 100 and 200 Bq/kg for other crops (spinach, cress, endive, leek, celery,…). Contamination levels for cesium-137 in spinach have decreased rapidly, from a maximum value of 200 Bq/kg just after deposition to 30 Bq/kg during the second half of May. As a result of the Chernobyl accident, legislation has been harmonized and new standards have been set for food crops in the event of a nuclear accident.

The extra dose burden in Belgium that could be derived from the measurements was very low. For adults, this exposure varied between 0.03 and 0.1 mSv during the first year after the accident. Due to different dietary habits and a higher sensitivity to radiation, this could rise to 0.3 mSv for the most exposed young children. For the period of 30 years after the accident, it is estimated that an additional dose of 0.1 to 0.2 mSv on average over the Belgian territory can be expected. The thyroid dose of a young child who would have drunk mainly the most contaminated milk would be 4 mSv for the first year after the Chernobyl accident.

The additional radiation exposure in Belgium as a result of the Chernobyl accident is therefore small compared to the average radiation exposure of our population (and even small compared to the geographical variations in natural radiation exposure). Even using the most pessimistic risk figures regarding cancer induction and congenital or hereditary defects, it is not possible to detect any increase. Other health effects (such as thyroid function problems, decrease in fertility, suppression of the bone marrow) were not observed in our country because they only occur if a high threshold dose is exceeded.

Tom Clarijs

Scientific collaborator