137CS concentrations in surface waters of the seas of Eurasia: results of expeditionary research in 2017

According to results of the field work conducted in 42nd cruise of the research vessel “Akademik Boris Petrov” (January-March, 2017) and 68th cruise of RV “Akademik Mstislav Keldysh” (June-August, 2017), the data on concentration of the man-made radionuclide caesium-137 in surface waters of the East China Sea, the South China Sea, Equatorial part of the Indian Ocean, the Red Sea and Mediterranean, Biscay Gulf, the English Channel, the Baltic Sea, North Atlantic, Norwegian Sea and the Barents Sea have been obtained. It was found that concentration of caesium-137 in the surface water of studied Eurasian seas is at a low level. The exception is the Baltic Sea, where the level of caesium-137 is much higher than the values observed before the Chernobyl accident. A higher concentration of caesium-137 in the surface waters of the East China Sea, compared with previous estimates, was found, which may be due to the significant discharge of a high-level liquid radioactive waste after the Fukushima-1 accident in 2011.