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Ionising radiation

Environmental Radioactivity - Medicine - Occupational Radiation Protection - Nuclear Hazards Defence

Ionisierende Strahlung

Radioactivity in foods

Radionuclides have partly chemical features as nutrients. Therefore, together with the nutrients they need for growth, plants and animals also take take up radionuclides. The activity level in foods depend on

  • the radioactivity content of the source media (soils, water),
  • the availability of the nutrients and the other substances contained in the soil and water as well as on
  • other conditions prevailing in the habitat of the animals and plants.

Foods can also be radioactively contaminated via the air. For example, the decay products of the gaseous radon-222 may deposit on the surface of foliage and be taken in by the leaves. In addition to the natural radioactivity, also radionuclides of artificial origin may get into the food chain, for example via the global fallout from atmospheric nuclear weapons tests or as a result of reactor accidents.

Within the framework of the Integrated Measuring and Information System for the Surveillance of Environmental Radioactivity (IMIS), agricultural products produced in Germany and drinking water are sampled on a regular basis.

Vegetables and fruits

Radionuclides in food

All foods contain natural radionuclides. In addition, the Chernobyl accident and the atmospheric nuclear weapons tests gave rise to artificial radionuclides in food. The natural radioactivity in foods contributing to the radiation exposure to man is mainly caused by the potassium isotope Potassium-40 and the long-lived radionuclides of the uranium-radium decay chain and the thorium decay chain. Among artificial radionuclides, especially caesium-137 is important for the radiation exposure to man.

Brazil nuts in front of a bowl

Natural radioactivity in food

With the essential elements for food taken up from the soil, also radioactive substances get into the plants and thus into the food chain. Knowledge of the content of natural radioactive substances in food is necessary to estimate the radiation exposure to man resulting from the ingestion of food. The results show that with regard to the mixed diet, there is no significant difference between the individual German regions.

Water poured into a glas

Radionuclides in mineral waters

Natural waters like groundwater and spring water always contain natural radioactive substances alongside traces of other minerals. This applies to drinking water and to mineral water, which is often taken from very low-lying water resources and therefore has a higher degree of mineralisation.

Silhouette of spoon and fork

Dose contribution through nutrition

All foods contain a certain amount of natural radionuclides which cause internal radiation exposure to humans when they are consumed. The exposure can be calculated from the radionuclide content and its age-dependent biological effect on the organism and the consumption rates. According to investigations, it amounts to 0.3 millisievert per year on average in Germany.

Wild boar searching for food

Radioactive contamination of mushrooms and wild game

As a result of the Chernobyl reactor accident, certain species of mushrooms and wild game are still highly contaminated with caesium-137 in some areas of Germany. This applies especially to Southern Germany – in particular Southern Bavaria and the Bavarian Forest.

Water reservoirSource: © Joachim Donath

Radionuclides in drinking water

The "Guidelines for the analysis and assessment of radioactive substances in drinking water by implementing the Drinking Water Ordinance" published in February 2017 form the basis for the comprehensive testing of water quality with respect to radioactivity-related parameters.

© Bundesamt für Strahlenschutz