Assessment of radioactivity levels at the Chernaya Bay underwater nuclear test site

Chernaya Bay is a 15 km long, 4-5 km wide and ca 80 m deep fjord located south on Novaya Zemlya. The sea floor in the fjord and the fjord’s surroundings contain very high levels of radioactivity due to testing of nuclear weapons during the Cold War. An underwater program of nuclear explosives was carried out as part of the FSU’s nuclear weapons testing program in the period of 1957 to 1961. At the eastern bank of the fjord underground testing of nuclear explosives were carried out in 1971 –74. Few measurements exist for the area due to tight security restrictions enforced by the Russian military. With only very rare exception non-Russian civilian investigators have been permitted into the area to obtain radioactivity samples.

Akvaplan-niva was commissioned by the Norwegian Radiation Protection Authority to conduct a joint Norwegian-Russian cooperation expedition to obtain more complete information on this important site. The expedition to Chernaya Bay was carried out in October 2000 in cooperation with the Murmansk Marine Biological Institute, Russian Academy of Sciences. The expedition included the collection of surface sediment samples from different sites to document radionuclide levels in the environment as well in biological samples.

Significant contamination of bottom sediments by the transuranium elements 239,240Pu and 241Am, in excess of global fallout, were detected in Chernaya Bay. Concentrations of 239,240Pu found in algae were 3-4 orders of magnitude higher than in algae from other areas in the Barents Sea. Marine sediments collected from stations outside of Chernaya Bay contained acceptably low levels of anthropogenic radionuclides indicating limited exchange of contaminated sediments from within the bay to the open Barents Sea is occurring in recent years. Future studies will look at radionuclide uptake and effects to biota inhabiting areas closely associated with the nuclear test sites.

Illustration: Anthropogenic radionuclides in marine sediments collected in the vicinity of the underwater nuclear testing site at Chernaya Bay, Novaya Zemlya (Carroll et al., 2002).

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