FISH AS BIOINDICATORS OF RADIOCESIUM POLLUTION IN AQUATIC ENVIRONMENTIN GREECE

It is well known that selected organisms can offer an easy tool for ra dioactive pollution ''signal'', whereas the radiological impact of the pollution event can also be early approached by the appropriate selec tion of the organism-bioindicator. The nomination of an organism as bi oindicator for a radionuclide is more complicated if compared with the stable isotopes even the biochemical behaviour is the same. The physi cal half-life of the radionuclides interferes to the ecological retent ion/elimination time and gives another parameter, the effective half-l ife, which defines the integrated activity concentration of radionucli de in the organism considered. Nevertheless, absolute activity concent ration, concentration factor in relation to sea-water and the effectiv e half-life of a radionuclide are the parameters, which can be used fo r the selection of organism-sentinels of radioactive pollution in aqua tic ecosystems. In the present study the selection of some aquatic org anisms as bioindicators for rdioacaesium (Cs-137 + Cs-134) pollution w arning in marine and freshwater environment in Greece are evaluated, i n relation to the ecological and the radiological impact assessment, a s well, based on a bulk of activity concentration measurements on mari ne and freshwater biota, during the period 1984 - 1989. The Chernobyl influence to the Greek aquatic environment was also interpretated in c onsideration to the organisms' response to the pollution event. Furthe rmore, marine organisms and freswater fish are suggested as bioindicat ors for radiocaesium pollution according to the established criteria.