On global ¹³⁷cs di usion in bottom sediments of northern seas

Abstract

In bottom sediments of the Laptev and the Kara seas 137Cs has been migrating with di usion coe cient ( D ) n ·(10-9-10-8) cm2/s during nearly 30 years. In the sediments pro le 137Cs concentration gradient was persisting between the layers. The trend of concentration decrease from the upper to the lower layers of the core was not violated along the entire path of radionuclide migration. 137Cs has been migrating in bottom sediments slowly; nearly 20% of the radionuclide stayed in the upper (0-1 cm) layer. In the Tsivolki Bay of Novaya Zemlya Archipelago 137Cs has been migrating in very low temperature conditions of water and bottom sediments (-1.0, -1.2°С). 137Cs concentration in the upper layer of the Laptev Sea and Tsivolki Bay sediments was characterized by close values, 7-18 and 14-24 Bq/kg, which correlate with global level of sediments contamination. The Tsivolki bay is ice-covered for 10 months. 137Cs pro le in the cores was forming due to radionuclide di usion in conditions of short warm period of terrigenic sedimentation. 137Cs concentration in the bay sediments and a type of the concentration pro le demon rated an absence of radionuclide release from buried radioactive objects in the bay. 137Cs di usion coe cients de nition computed with experimental data will be necessary in radionuclide migration models and scienti cally supported measures of damage minimization from exposure to the radiation factor.