Radioactivity in Food: Experiences of the Food Control Authority of Basel-City since the Chernobyl Accident

The contamination of our environment and of food with artificial radionuclides originates from several sources. First, nuclear powers spread contamination all over the Northern Hemisphere by carrying out more than 600 atmospheric bomb tests from 1945 to 1963. The peaceful use of nuclear fission brought several accidents in nuclear installations [nuclear power plant (NPP)]. This began in the late 1940s and ended recently with the NPP’s core meltings at Fukushima-Daiji in 2011. The catastrophe at the Chernobyl NPP in 1986 spread enormous fallout over most parts of Europe. Besides the artificial contamination, one has to mention the exposure to naturally occurring radionuclides from the uranium and thorium decay series. From 1980 on, the State Laboratory Basel-City began a monitoring programme of food. Special equipment for the analysis of α-, β-, and γ-emitting radionuclides had to be built. In 1986/1987, the laboratory had to manage thousands of samples according to the accident at Chernobyl. The Government estimated the dose of the mean Swiss population from the ingestion of contaminated food to be 1 to 2 mSv. Today, the contamination of food has lowered significantly. The Office of Public Health estimated the total ingested dose of about 0.3 to 0.4 mSv/year. The main contribution comes from potassium-40 (40K; 0.2 mSv/year) and from natural radionuclides of the uranium and thorium decay series. The remaining contamination from the bomb fallout is less than 0.1 mSv/year