Deep-water profiling of 137Cs and 90Sr in the Black Sea: a further insight into dynamics of the post-Chernobyl radioactive contamination

The first post-Chernobyl measurements of vertical distribution of 137Cs in the abyssal Black Sea waters have been conducted in the vicinity of submarine canyon Viteaz together with profiling of 90Sr. This allowed showing an increase in 137Cs concentration and the low 90Sr/137Cs activity ratio (≈0.2) at 1,000 m water depth, suggesting the long-distance influence of the Danube River runoff through the Viteaz Canyon. Calculation of inventories of 90Sr and 137Cs in oxic and anoxic Black Sea waters and their comparison with the total input of these radionuclides to the Black Sea after the Chernobyl accident have revealed considerable accumulation of them in the deep water column.