Biological concentration of radionuclides in plants and animals after Chernobyl catastrophe

The 137Cs radioactivity and its distribution in plants (trees, mushrooms, berries, duckweed, and etc.) and animals (insects, mice, fish, and etc.) were measured in contaminated areas of southern Belarus, which was highly polluted by radionuclides as a result of the Chernobyl catastrophe in Ukraine in 1986. Gamma spectrometry of 137Cs was carried out, and a computer graphic imaging analysis was performed to visualize the distribution of radioactive nuclides in the organisms. The specimen was placed on the imaging plate, the plate was exposed for 20 h. High 137Cs radioactivity was detected in both the animals (mice, moles, dragonflies, grasshoppers, and fish) and the plants (pine trees, oak leaves, mushrooms, berries, duckweed). The 137Cs radioactivity in the organisms was proportional to the radioactivity in the soil. Assessment of its distribution showed that 137Cs was highly concentrated in muscle, but there were no substantial differences in 137Cs radioactivity according to organ or species. Computer graphic imaging analysis clearly revealed non-uniform distribution of 137Cs radioactivity in the animals and plants. In pine trees, the highest level of radioactivity was found in the bark, and it decreased toward the center of the tree. In conclusion, the authors suggest that self-cleaning of the soil will require a very long time and that the biological concentrations will persist and increase in higher animals for a long time, resulting in accumulation of both external and internal radiation exposure in animals. (K.H.)