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Ionising radiation

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

Ionisierende Strahlung

Radiation exposure from natural radionuclides in food

  • 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.

Effective dose is a measure of the effect of radiation acting on human organs and tissue when an individual eats or drinks something (ingestion). It is expressed in the unit sievert. The various types and energies of radiation have different effects on human organs and tissue.

The anticipated radiation exposure in a certain period of time can be estimated by converting the activity of a radionuclide ingested through food with the applicable dose coefficient for the radionuclide. These coefficients express the effective dose in the body per becquerel of ingested activity depending on the age of the individuals (unit: sieverts per becquerel).

According to the "Calculation Guide Mining", the activity ingested through food per year can be calculated from the specific activities determined for individual foods and the average consumption rates of various foods for a reference person per year (in kilograms per year) stated in table 3 or from the corresponding values for the total diet.

Mean consumption rates of the reference person in kilograms per year *
foodage group
<= 1 year> 1-2 years> 2-7 years> 7-12 years> 12-17 years< 17 years
* from the German Federal Law Gazette (BGBl) 2001 Part I Number 38, published in Bonn on 26 July 2001, page 1808 to 1809, last amended Federal Law Gazette Part I Number 51, published in Bonn on 13. October 2011, page 2046
1) 160 litres are added to the amount of 55 litres of drinking water consumed by an infant per year, assuming that the infant is not breastfed but is only fed infant formula products produced outside the region and regarded as not contaminated. Next, it is assumed that 0.2 kilogram of concentrate (corresponds to 1 litre of milk) is dissolved in 0.8 litre of water.
2) Food variations are to be considered alternatively; depending on the result of the exposure calculation, the least favourable food variation has to be taken as a basis.
3) The proportion of freshwater fish is an average of 17 per cent of total fish consumption and has to be adapted to regional characteristics.
4) domestic fresh fruit and fruit products
drinking water (l/a)55100100150200350
breast milk 1,2)200
milk, dairy products45160160170170130
fish 3)0,5334,557,5
Meat, sausage, eggs51350658090
grain products12308095110110
fruit, juices 4)254565656035
potatoes, root vegetables, juices304045555555
leafy vegetables36791113
vegetables, vegetable products, juices51730353540

Based on the results of the total diet analysis by the Federal Office for Radiation Protection, the following table shows the radiation exposure from food consumption for the various age groups of the population in the Federal territory:

Mean effective ingestion dose due to radionuclides of the natural decay series and potassium-40 in areas with average natural radioactivity in millisieverts per year
foodage group
<= 1 year> 1-2 years> 2-7 years> 7-12 years> 12-17 years> 17 Jahre
* including drinking water, ** according to the UNSCEAR-Report 2000
drinking water0,0110,0080,0100,0130,009
total diet (without drinking water)0,336*0,1810,1410,1380,1600,041
effective dose (without potassium-40)0,3360,1920,1490,1480,1730,050
effective dose by potassium-40-activity in humans **0,1850,1850,1850,1850,1850,165
effective dose - sum0,5210,3770,3340,3330,3580,215

Depending on age, the contributions of the uranium decay series and the thorium decay series to the effective dose, which ranged from 0.04 to 0.27 millisievert per year, differ distinctly. In line with common international specifications on age distribution for weighted values in population groups (adults: 65 per cent, children: 30 per cent, infants: 5 per cent) as given in the United Nations Scientitic Committee on the Effects ot Atomic Radiation (UNSCEAR) 2000, an age-weighted mean of 0.10 millisievert per year can be derived. Taking into account potassium-40 which makes an age-weighted contribution of about 0.17 millisievert per year, results in a natural radiation exposure of the population from food intake of about 0.27 millisieverts per year with average dietary habits.

These data are in good agreement with those stated in the UNSCEAR Report 2008: In the report, the authors estimate the contribution to ingestion due to potassium-40 at 0.17 millisievert per year, the contributions from the uranium decay series and the thorium decay series at 0.12 millisievert per year.

For comparison purposes: The total natural radiation exposure in Germany amounts to 2.1 millisieverts per year on average. External radiation exposure amounts to about 0.7 millisievert per year; inhaling the radioactive noble gas radon and its decay products causes an average radiation exposure of 1.1 millisieverts per year. Radiation exposure through food ingestion is naturally due to the properties of the soils on which the agricultural products are produced. It varies regionally only to a slight extent and is constant.

State of 2017.01.18

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