Evolution of 137Cs Activity Concentration in the Aegean Sea

A review of the evolution of 137Cs activity concentrations in the Aegean Sea is presented almost 34 years after the Chernobyl accident. The data from field measurements are interpreted considering the different water masses present in the Aegean Sea, for better understanding of 137Cs spatial and temporal variation. The last 15 years, a lot of effort is given in the study of the vertical advection of 137Cs and the related processes in the deep basins of the Aegean Sea. These results provided significant information about the average values along with depth of the velocity and diffusion parameters. The role of 137Cs as a circulation and mixing tracer is undergoing a gradual weakening, since the gradient of its activity concentration between the water masses is small. 137Cs is proved to be a valuable radiotracer for identifying the Black Sea Water masses since they are still enriched with higher values of 137Cs compared to the background values in the Mediterranean Sea.