RADIONUCLIDES IN FISH OF THE CHERNOBYL EXCLUSION ZONE: SPECIES-SPECIFICITY, SEASONALITY, SIZE- AND AGE-DEPENDENT FEATURES OF ACCUMULATION

The results of studies during 2006-2013 of fish from 12 water bodies with different hydrological mode and levels of radioactive contamination within the Chernobyl exclusion zone are presented.The specific activity of 90 Sr and 137 Cs for 17 species of fish, concerning various ecological groups was estimated.The fish of stagnant water bodies of the Chernobyl exclusion zone continue to be characterized by the high concentration of 90 Sr and 137 Cs.Radionuclide specific activity in fish of closed water bodies of the Chernobyl exclusion zone during our studies in all cases exceeded maximal permissible levels, according to the standards, accepted in Ukraine for fish production: in 53-2892 times on 90 Sr and in 6-212 times on 137 Cs.In fish of the riverbed sites of the Pripyat River within the Chernobyl exclusion zone some single cases which exceeded the maximal permissible level on 137 Cs, mainly the predatory fish, were registered.The analysis of radionuclide specific activity data in fish of various size, weight and age groups on an example of the common rudd and the European perch from Glubokoye Lake has allowed the revelation of a dependence of 90 Sr and 137 Cs accumulation on the weight of body and the age of fishes.