The basic patterns of the distribution, migration and accumulation of radionuclides in the bottom sediment of the Baltic Sea

Abstract

This paper focuses on the impact of certain factors on the contemporary distribution of natural (226Ra, 232Th, 40К) and anthropogenic (137Cs, 60Co) radionuclides in the sediments of the Baltic Sea. The results of the study suggest that the distribution of 137Cs is determined by the content of hydromica of silty-clay and clay grain-size fractions, while radiocaesium is mainly accumulated by silty fractions. The accumulation of 226Ra by bottom sediments is mainly determined by the pH geochemical barrier at the water-seafloor boundary. The accumulation of 232Th occurs mainly in clayey fractions of the sediment. The distribution and accumulation of 40K is predominantly determined by the ratio of potassium contained in hydromica minerals. Significant 60Co activity was registered only in a few samples.

Keywords

• radionuclide distribution patterns
• Baltic Sea
• hydromica
• pH barrier
• sediment fractions
• grain-size composition