The accumulation of 137Cs and its stratification in Cladonia lichens growing in the area of Kola nuclear power plant have been studied. For this purpose, samples of reindeer lichens were selected at 12 test sites in the sanitary protection zone of the station, in the observation zone, and in the background area. The specific activities of 137Cs in the samples were determined using a scintillation gamma spectrometer. The weighted average specific activities of 137Cs in Cladonia lichens were 22.3–104.8 Bq/kg, while most of the radiocaesium was concentrated in the upper layers of the lichen. Statistical data processing using a single-sample t-test, Spearman’s coefficient, and cluster analysis indicated the dominant role of global fallout in the 137Cs input into the lichens, while the possible impact of the Kola nuclear power plant on this process is limited to the sanitary protection zone.

The paper presents data obtained by studying the modes of 137Cs, 90Sr, 239,240Pu, and 237Np occurrence in different genetic horizons of Albic podzols in the area of the Kola nuclear power plant (KoNPP). The data were obtained by artificially introducing solutions of the isotopes into dry soil samples. Comparison of the results with literature data on the distribution of these radionuclides in soils elsewhere around Russia showed that the radionuclides are much more mobile in northern Albic podzols than in soils studied elsewhere in Russia: the total amounts passing into water-soluble and exchangeable forms are up to 33% 137Cs, up to 82% 90Sr, up to 39% 239, 240Pu, and up to 69% 237Np.

The content and profile distribution of 137Cs in iron-illuvial dwarf and shallow-podzolic podzols (Albic Podzols) under bilberry-lichen and green-lichen-bilberry pine forests in the located near the Kola Nuclear Power Plant have been analyzed. The pollution density (reserve) of 137Cs in the root-inhabited layer (0–30 cm) in the studied soils was significantly lower than the established control level of 37 000 Bq/m2 and amounts to 530–2459 Bq/m2. A significant part of 137Cs (60 to 90%) was concentrated in mineral horizons. It has been shown that the pollution density of 137Cs in the observation zone of a nuclear power plant was mainly due to global fallout. The greatest influence on 137Cs accumulation in the studied soils was exerted by the organic matter reserve.