Accumulation and distribution of90Sr and137Cs in birch in the zone affected by liquid discharge from the Beloyarskaya Nuclear Power Plant

The data are presented that concern the accumulation and distribution of artificial radionuclides (⁹⁰Sr and¹³⁷Cs) in the aboveground organs of birch growing in the vicinity of the Beloyarskaya Nuclear Power Plant (NPP) in the permanently inundated part of the Ol'khovka swamp, on its banks periodically flooded with water, and in watershed areas not influenced by the swamp (control). Concentrations of both radionuclides in birch trees from the swamp and its banks were several times as high as in trees from the watershed. The distribution of⁹⁰Sr in birch trunk proved to be acropetal. Trees growing on the inundated part of the swamp and on dry land significantly differed in the distribution of¹³⁷Cs. The factors controlling the distribution and accumulation of both radionuclides in birch trees growing in these areas are discussed.