14. Gamma-Ray Radionuclides in Sediments from Mamaia Beach on the Romanian Black Sea Coast

Tourist activities on the seaside, but not exclusively, are dependent of the quality of the environmental components from the coastal zone. The water and the substrate are some of the main components. Their importance is supported, on the other hand, by their background role in the marine ecosystem. The surveillance of the radioactive indicator for sediments helps at knowing its distribution in the marine ecosystem and at assessing the risk of exposure to ionizing radiation for people. Setting-up and maintaining a database is necessary both for the present state, as well as to assess trends. A further study may reveal important knowledge in combination with other environmental factors, such as hydrodynamics, chemicals, for example, and their impact on biota. The Navodari – Mamaia area, which is now contained in a plan to rehabilitate the shoreline, was taken as a case study. The samples were collected on seven profiles distributed in that area, all from the sands at terrestrial vegetation limit and up to sediments submerged up to 12 m. The 56 samples were analyzed in IFIN-HH underground laboratory with ultra-low radiation background. The results indicated the presence of artificial radionuclide Cs-137, with values between 0.5 and 10.5 Bq/kg. The natural radionuclide K-40 is also present in the range of 55–494 Bq/kg sediment.