Discharges of nuclear waste into the Kola Bay and its impact on human radiological doses

The civilian nuclear icebreaker facility, RTP "ATOMFLOT," is located in Kol a Bay, Northwest Russia, as are several nuclear installations operated by t he Russian Northern Fleet. A treatment plant at the Atomflot facility disch arges purified nuclear waste into the bay at an annual rate of 500 m(3). As a result of plant modifications this rate will soon increase to 5000 m(3)/ yr. Evidence of minor leakages of Co-60 are reported by Matishov et al. (19 99) in the vicinity of Atomflot as well as near several military installati ons in Kola and the adjacent Motovsky Bays. Cs-137 levels reported in the p resent study for seawater and. seaweed collected from locations within the bays are at expected levels except in the vicinity of Atomflot, where the C s-137 level in a seaweed sample was 46 +/- 5 Bq/kg w.w. indicating signific ant uptake of radionuclides to biota. Uptake also may be occurring in higher trophic levels of the food web throu gh environmental exchange and/or biotransformation. We consider the impact of the present and anticipated discharges from Atomflot through a radiologi cal dose assessment for humans consuming fish from Kola Bay. Mixing and tra nsport of nuclear waste is simulated using a simple box model. Maximum dose s, assuming consumption of 100 kg/yr of fish, are below 10(-9) Sv/yr; the p lanned ten-fold increase in the discharge of treated waste will increase th e doses to below 10(-8) Sv/yr. Using data on radionuclide levels in sediments and assuming equilibrium par titioning of radionuclides among sediment, seawater and fish, we estimate t hat the total doses to humans consuming fish from different areas of Kola a nd Motovsky Bays, including adjacent to military-controlled nuclear install ations, are approximate to 10(-7) Sv/yr. Nuclear activities in Kola and Mot ovsky Bays thus far have had minimal impact on the environment. Discharges from the treatment plant currently account for less than 0.2% of the total dose predictions. The increase in discharges from the treatment plant is no t expected to change significantly the relative importance of sources contr ibuting to radiological doses related to human consumption of fish. (C) 199 9 Elsevier Science Ltd. All rights reserved.