[The dynamics of 137Cs and 40K accumulation in the tissue of food species of fish in the Tobol and Irtysh Rivers during 1995-2007].

The results of long-term investigations of 137Cs and 40K accumulation in the tissue of food species of fish in the Tobol and Rivers were analyzed. It was revealed, that the highest specific activity of 137Cs is characteristic for predatory species of fish. Yearly, seasonal and age peculiarities of 137Cs accumulation in fish were examined in this work. The tendency to the lowering of the specific activity of the man-caused 137Cs values was revealed for the entire time of radio-ecological investigations of fish from the Tobol and Irtysh Rivers. The comparative analyses of the 137Cs accumulation in fish tissue were carried out at the different parts of the studied rivers.