Cs content and concentration factors in benthic organisms in the dump sites for solid radioactive waste in the Kara Sea

Radioactive contamination was studied in macrobenthic invertebrates and algae of the Abrosimov, Stepovoy and Tsivolky Bays of the Novaya Zemlya Archipelago and the adjacent regions of the Kara Sea during the cruises 73d and 81st on board R/V Professor Shtokman in the years 2005–2006. Maximum concentration 137Cs in sediment in studied area has been detected in the layer 10–12 cm in the Abrosimov Bay (150 Bq/kg) and in the layer 4–6 cm in the Stepovoy Bay (100 Bq/kg). Concentration of 137Cs in benthos was up to 3.19 Bq/kg of wet weight. The highest concentration has been found in benthos of the Abrosimov and Stepovoy Bays: the holothurian Myriotrochus rinkii, the isopod Saduria sabini, ophiuroids Ophiocten sericeum and Stegophiura nodosa. Myriotrochus rinkii, Saduria sabini and the brown alga Laminaria saccharina were characterized by the highest 137Cs concentration factor – 994, 599 and 425 respectively. Caesium-137 contamination occurs locally in the studied area closed to the radioactive waste disposal and does not affect on qualitative structure of the macrobenthic communities