Strontium-90 in Seawater and Bottom Sediments of the Barents Sea Shelf (2000–2019)

The long-term dynamics of the 90 Sr concentration in water and bottom sediments of the Barents Sea is analyzed. The dependence of the distribution of 90 Sr on the conditions of the geographical environment of the reservoir is shown. A rapid decrease in the specific and volumetric activity occurred after the prohibition of nuclear weapons testing and rationing of radioactive discharges by chemical plants in Western Europe in the 1960s and 1990s. Its current concentration is 3–5 times lower compared to the 1990s. The nature of the 90 Sr distribution in the sea is determined by the currents and macro- and mesoscale dynamics of the waters in the basin. In bottom sediments, the concentration depends on the bottom relief, the granulometric composition, and the intensity of sedimentation. The combination of these factors and the availability of modern sources of 90 Sr allows us to distinguish two types of marine accumulation sites, i.e., the coastal zone and the open water of the shelf. The cyclic variability and the general tendency of decreasing concentrations of 90 Sr in the Barents Sea are shown.