The Sedimentation Rate in the Crimean Hypersaline Lake Aktashskoye Estimated Using the Post-Chernobyl Artificial Radionuclide 90Sr as a Radiotracer

Artificial 90Sr is one of the most important long-lived radionuclides of global radioactive fallout from the atmosphere after the testing of nuclear weapons and the accident at the Chernobyl Nuclear Power Plant in 1986. In addition to fallout from the atmosphere, secondary radioactive contamination of Crimea was mainly from the Dnieper River and the North Crimean Canal, which occurred until 2014. 90Sr was used as the optimal radiotracer for estimating the rate of sedimentation in the Crimean hypersaline lake. Its vertical distribution in the bottom sediments was assessed. In the core of the bottom sediments, the detectable activity of 90Sr in layers 0–1.5 cm and 16.7–21.9 cm was absent, and it was determined again in the layer of 15.5 cm, which was associated with atmospheric fallout of the radionuclide after the Chernobyl NPP accident. There were well-isolated peaks of specific activity in layers at a depth of 4.6 and 13.3–14.3 cm. The calculated rate of sedimentation varied within 0.5–1.5 cm year−1: the minimum rate corresponded to the period 1971–2017, and the highest rate corresponded to the period 1954–1971.