engleski

Activity distribution of fission products in the surface water of the Adriatic Sea

The activity concentrations of 90Sr and 137Cs in the surface waters of the Adriatic Sea were investigated twice a year (in April and October, if possible) over the 1963 - 1997 period at four locations (towns of Rovinj, Rijeka, Split and Dubrovnik). The fallout samples were collected monthly in the town of Zadar. An exponential decline of radioactivity in sea water as well as in fallout samples followed the nuclear moratorium. After the nuclear accident at Chornobyl, higher levels of 137Cs were detected again, while the activity concentrations of 90Sr, that is less volatile than radiocaesium, have not been significantly increased. The coefficient of correlation between 90Sr activity concentrations in fallout and sea water was found to be fairly good, representing the fact that approximately 85% of man-made radioactive contamination in the Mediterranean Sea comes from fallout. The long term measurements were used to model the mean residence time of 90Sr in sea water. No significant variations of mean residence time on different locations were found, implying the uniform distribution of 90Sr through the mixed layer of the Adriatic Sea.

marine radioactivity, fission products, mean residence time, Chornobyl nuclear accident

nije evidentirano