p. 233 - 243 SUR LA RADIOACTIVE DE L'EAU DE MER DANS LA BAIE DE MAMAIA PENDANT LA PERIODE 1986-1992 V. Patrascu Institut Roumain de Recherches Marines Constanta Abstract This paper reviews the gamma measurements of sea water radioctivity in Mamaia Bay for a recent lapte of time and estimates the evolution of the radionuclides concentrations as compared to Chernobyl moment and their present level as compared to the previous "clean" years. We have noticed 40K (a few Bq/1), 228Ac and 226 Ra (of the order of 10-1, 10-2 Bq/1) for their contributions to the natural radioactivity. The fission and activation products have increased the inventory of radionuclides from the environment (54Mn, 60Co, 106Ru, 110mAg, 125Sb, 134Cs, 137Cs). The natural processes from the marine environment diminish that increase, their concentration had low values in 1992 (a few tens of mBq/l for 137Cs). The paper includes interpretation possibilities and admissibility criteria of radiation exposition levels. Mamaia could be the pretext for presenting the general tendency of the radionuclides fund observed along the Romanian littoral.