Abstract
The analysis of the long-term evolution of the 90Sr concentration field in water, sediments and biota of the Barents Sea is given. The writing is based on original data collected by the MMBI during longterm studies of the Arctic seas. Modern ideas about the content and distribution patterns of this radionuclide in various elements of the regional marine ecosystem have been obtained. There is a steady downward trend in the long-term dynamics of 90Sr concentrations. The trend line is complicated by quasi-two-year and seven-year oscillation cycles, which are apparently caused by the natural dynamics of the Atlantic transit of radioactivity in the Barents Sea. The current 90Sr concentration field is characterized by its low content in water, bottom sediments and biota in the last ten years. Stable low concentrations are caused by low-level atmospheric fallout in the North Atlantic and the Barents Sea as a result of gas-aerosol emissions from operating reactor installations of nuclear power plants and the fleet. The transfer of waters by transatlantic currents remains relevant for the Barents Sea. These waters are polluted by discharges of liquid radioactive waste by radiochemical plants and the nuclear infrastructure of Northern Europe. Domestic point potential sources of radiation give a local effect of pollution in the areas of the coastal zone of the Kola Peninsula and Novaya Zemlya.