Radioactive contamination of mushrooms from Polis'ke Forestry (Kyiv Region, Ukraine) long after the Chornobyl accident.

A study of the radiocaesium activity in fruitbodies of 54 mushroom species from 18 locations of Polis'ke Forestry complex was carried out with (cid:2) -spectrometry. In some mushroom samples, strontium was determined with a radiochemical method. However, the mushrooms accumulated 137 Cs one to three orders of magnitude more actively than 90 Sr. The highest levels of 137 Cs activity, recorded in Lactarius rufus , Imleria badia , Paxillus involutus and Cortinarius praestans from the forest area at the settlement of Polis'ke in 1998 and 2000, exceeded 1 MBq/kg dry mass. By 2018, the activity of 137 Cs in 60.0% and 37.84% of mushroom samples in the Zelenopolyans'ke and Steshchyns'ke Forestries, respectively, exceeded the maximum permissible level valid in Ukraine, 2,500 Bq/kg dry mass. Significant differences in the levels of contamination of the same species are noted not only at different locations, but also within the same sampling site, which is probably associated with a complex of factors which are difficult to assess, such as extremely heterogeneous nature of contamination, depth of mycelium in the soil layer, and micro-climatic conditions in the place where individual fruitbodies grow. The data obtained indicate a persistent risk to the population due to internal exposure as a result of uncontrolled consumption of wild mushrooms in this region. In 2018, the potential equivalent dose per year (contribution of 137 Cs only) reached maximum values of 0.239 mSv in Suillus spp. and 0.130 mSv in Imleria badia from Zelenopolyans'ke Forestry.