There have been many alarmed comments regarding the radioactivity of mushrooms. This article informs you of some unfounded opinions.
The Chernobyl accident released tons of radioactive particles in particular cesium 137. By feeding on plant debris, the mushroom mycelium draws its nutrients. It is able to extract radioactive elements.
Do all mushrooms have the same radioactivity?
Following the disaster, some mushrooms have stored large amounts of radioactivity. Those are the underground filaments (mycelium) which were highly concentrated. The toxicity rate was not the same for all mushrooms because it varies depending:
► on the size of the mycelium of fungi,
► of the layer where it is located.
Each mushroom species has several characteristics that will influence the cesium concentration ability:
► habitat (grassland, deciduous forest, coniferous)
► its means of nutrition (symbiotic parasites)
► implementation of the mycelium (superficial or deep), etc.
Over time, the radioactivity tends to descend and to affect lower surface layers, thus the mycelia of other mushroom species.
In France, CRII-RAD (Commission of Independent Research and Information on Radioactivity) conducted a ranking indicating the level of concentration of different species. This study is based on analysis of 900 mushrooms collected in various regions of France from 1986 to 1997, a period of strong contaminations –
► The most affected species were:
► Bolet bai, Bolet pines, Sweet Tooth, Blue Foot,
► Chanterelle in tube or yellowing, small gray mushrooms,
► Slightly less affected:
► Chanterelles, parasol mushrooms, Lactarius delicious
► Porcini, Trumpets, blood Lactarius,
► Much less affected:
► Small mushrooms (Marasmius Oreades), Morels,
► Rough boletus and Russules.
Mentioned here are only the species most consumed in France.
In 2016, is still radioactivity present in France, in Europe, or in the world?
If we look at the passage of the Chernobyl cloud and map of CRII-RAD readings:
► the most affected regions in France are all eastern France, Corsica to Alsace,
► northern Italy and Austria were also heavily contaminated, almost as much as the Eastern Europe countries,
► fallouts were lower in the west of France.
The radioactivity is still present, as it does not disappear overnight. Cesium 137 has a half life of 30 years.
The relevant European standard is 600 Bq / kg of fresh mushrooms. In France, in the most affected regions, the value is 400 Bq / kg.
In Catalan country where our dried mushrooms are harvested, the value is only 50 to 60 Bq / kg.
Is there a higher risk of contamination if you buy imported mushrooms? With a maximum level of 600 Bq / kg would have to eat 125 kg / year of fresh mushrooms per person to reach the maximum radiation dose acceptable by humans is 1 mSv per year.
However for the sake of prevention, CRII-RAD advises mushroom enthusiasts to refer to the scale of contamination it has established, to prevent species at risk and limit their consumption of moderately contaminated species, especially when they come from the most exposed areas, including mountain areas of the eastern half of France.
Regarding Fukushima, the samples show that radioactivity from Fukushima has been less than the daily variations of natural radioactivity in France.
Photo creds "Sarcoscypha coccinea": Michel RICHARD - Société Mycologique du Haut-Rhin (Mycological Society of Upper Rhine)