Frequency distributions of 90Sr and 137Cs concentrations in an ecosystem of the "Red Forest" area in the Chernobyl exclusion zone.

In the most highly contaminated region of the Chernobyl Exclusion Zone, the "Red Forest" site, the accumulation of the major dose-affecting radionuclides (90Sr and 137Cs) within the components of an ecological system encompassing 3,000 m(2) was characterized. The sampled components included soils (top 0-10 cm depth), Molina caerulea (blue moor grass), Camponotus vagus (carpenter ants), and Pelobates fuscus (spade-footed toad). In a comparison among the components of this ecosystem, the 90Sr and 137Cs concentrations measured in 40 separate grids exhibited significant differences, while the frequency distribution of the values was close to a logarithmically-normal leptokurtic distribution with a significant right-side skew.