Radioecological Research on Ecosystems of Beloyarsk Npp on the Ural

The BNPP is one of the large nuclear sites of the Ural region. During several years of investigations there were estimated the contributions made by the gas-aerosol fallouts and liquid radioactive waste effluents discharged from the BNPP at normal operation mode into the contamination of natural ecosystems. In general a 50-year period of the BNPP operation did not lead to any increase in the content of 90Sr,137Cs and 238-240Pu in the soil- plant cover of its 30-km zone. A long -term discharge of waste waters from the BNPP into the Olkhovsk bog - river ecosystem resulted in the increase of the content of the radionuclides in water and in the bottom sediments of the bog. The stock of radionuclides in the Olkhovsk bog is about 3.7T Bq at present time; and 99% the radionuclides are in the bottom sediments. This fact makes the Olkhovsk bog to be a potential source of contamination of the conjugated territories and the open hydrographic network. An annual departure of the radionuclides from the Olkhovsk bog was calculated. It is 2. 1M6Bq/yr for isotopes Pu, 1170 MBq/yr for 90Sr and 1581 MBq/yr for 137Cs.