Over 600 bomb tests in the atmosphere led to a contamination of the Northern Hemisphere with long-lived radionuclides, such as radiocaesium, radiostrontium, and plutonium.
In addition to the emission controls of the NPPs and other radiation-producing facilities, the monitoring of radioactive fallout from the atmospheric, nuclear bomb tests is of special concern. Today, five NPPs are producing about 38% of the electric power in Switzerland. In 1969, the first nuclear power plant (NPP) of Beznau came on line to produce electric power. Some years later, the federal government initiated a countrywide monitoring programme. In the 1950s, Otto Huber and his team from the University of Fribourg started the regular monitoring of radioactivity in Switzerland. The remaining contamination from the bomb fallout is less than 0.1 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 Office of Public Health estimated the total ingested dose of about 0.3 to 0.4 mSv/year. Today, the contamination of food has lowered significantly. The Government estimated the dose of the mean Swiss population from the ingestion of contaminated food to be 1 to 2 mSv.
In 1986/1987, the laboratory had to manage thousands of samples according to the accident at Chernobyl. Special equipment for the analysis of α-, β-, and γ-emitting radionuclides had to be built. From 1980 on, the State Laboratory Basel-City began a monitoring programme of food. Besides the artificial contamination, one has to mention the exposure to naturally occurring radionuclides from the uranium and thorium decay series. The catastrophe at the Chernobyl NPP in 1986 spread enormous fallout over most parts of Europe. This began in the late 1940s and ended recently with the NPP’s core meltings at Fukushima-Daiji in 2011. The peaceful use of nuclear fission brought several accidents in nuclear installations. First, nuclear powers spread contamination all over the Northern Hemisphere by carrying out more than 600 atmospheric bomb tests from 1945 to 1963. The contamination of our environment and of food with artificial radionuclides originates from several sources.
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