The radioactivity of fungi

Numerous alarmist comments concerning the radioactivity of fungi. This article informs you of the unfoundedness of certain opinions.

The Chernobyl accident released tons of radioactive particles, in particular Cesium 137. By feeding on plant debris, the mycelium of the fungus draws its nutrients. It is capable of extracting radioactive elements from it.

Do all fungi have the same radioactivity?

Following the disaster, some fungi stored large amounts of radioactivity. It was the underground filaments (mycelium) that were highly concentrated. The toxicity rate was not the same for all the fungi because it varies:

► depending on the size of the mycelium of certain fungi,

► the layer where it is located.

Each species of mushroom has several characteristics that will influence the capacity of Cesium concentration:

► habitat (meadow, deciduous forest, conifers),

► its mode of nutrition (symbiotics, parasites),

► implantation of the mycelium (superficial or deep), etc. 

Over time, the radioactivity tends to descend and affect less superficial layers, therefore the mycelium of other species of fungi.

In France, the CRII-RAD (Independent Research and Information Commission on Radioactivity) has carried out a classification indicating the concentration capacity of different species.

This study is based on 900 analyzes of fungi taken from various regions of France from 1986 to 1997, a period of heavy contamination.

In the order of analyzes of the most affected species were:

► Bay boletus, Pine boletus, Pied de mouton, Pied bleu,

► Chanterelle tube or yellowing, Petit gris,

A little less affected:

► Chanterelles, Coulemelles, delicious lactaria,

► Ceps, Trumpets, Blood milk,

Much less affected:  

► Small Mousserons (Marasme des Oréades), Morels,

► Rough boletus and Russules.

Only the species widely consumed in France are mentioned here. 

And today, is radioactivity still present in France, in Europe, in the world?

If we look at the passage of the Chernobyl cloud, as well as the map of the CRII-RAD readings:

► the most affected regions in mainland France are all of eastern France, from Corsica to Alsace,

► Northern Italy and Austria were also heavily contaminated, almost as much as the Eastern European countries,

► the impact was less in the West of France.

The radioactivity is always present, it does not disappear overnight. Cesium 137 has a half-life of 30 years.

The current 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 50-60 Bq / kg.

 

Is there a big risk of contamination if you buy imported mushrooms? 

With a maximum rate of 600 Bq / kg, it would be necessary to eat 125 kg / year of fresh mushrooms per person to reach the maximum radiation dose acceptable to humans, which is 1mSv per year.

However, for the sake of prevention, the CRII-RAD advises mushroom enthusiasts to refer to the contamination scale it has established, to avoid species at risk and to limit their consumption of moderately contaminated species, especially when they come from the most exposed areas, and in particular from the mountain sectors of the eastern half of France.

With regard to Fukushima, the samples show that the radioactivity from Fukushima was lower than the daily variations of natural radioactivity in France.

Photo credit “Pézize scarlet”: Michel RICHARD – Haut-Rhin Mycological Society

 

Come visit us and discover the originality of our Mushroom Shop in Eguisheim in Alsace!