Analysis of the specific activity of cesium-137 in the fruiting bodies of representatives of the genus Leccinum collected during mass fruiting in the vicinity of the Seytesyavr Lake (Khibiny) showed that it does not exceed the permissible values. The data obtained can be used as reference data for comparison with the results of accumulation of cesium-137 by fruiting bodies of species of the genus Leccinum collected in other regions.

For the first time, pH factor of soil-water extract was used to separate genus Leccinum systematic units. It was found that the increased acidity of raised sphagnum bogs and boggy areas with a developed green mosses cover leads to cesium-137 accumulation in fungi fruit bodies of Leccinum holopus.

The accumulation of cesium-137 by the cap and stalk of fruiting bodies of Leccinum aurantiacum (Bull.) Gray from the podzolic soil of an aspen forest 30-35 years old was compared with spruce undergrowth, which resumes after felling and damage to the litter. The average specific activity of caesium-137 for dry caps is 1589±85 Bq/kg and for stems 879±72 Bq/kg. It has been established that the specific activity of cesium-137 does not exceed the allowable values. The coefficients of accumulation of cesium-137 by parts of fruiting bodies from the soil vary in the following range: for caps from 5.4 to 6.8, and for legs from 1.2 to 2.8. The maximum specific activity of caesium-137 was found in the forest litter 461±54 Bq/kg. With increasing depth, it naturally decreases.

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