Anthropogenic radioactivity in the Arctic Ocean — review of the results from the joint German project (original) (raw)
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Benchmarking of numerical models describing the dispersion of radionuclides in the Arctic Seas
Science of The Total Environment, 1997
As part of the International Arctic Seas Assessment Project (IASAP) of the International Atomic Energy Agency (IAEA), a working group was created to model the dispersal and transfer of radionuclides released from radioactive waste disposed of in the Kara Sea. The objectives of this group are: (1) development of realistic and reliable assessment models for the dispersal of radioactive contaminants both within, and from, the Arctic ocean; and (2) evaluation of the contributions of different transfer mechanisms to contaminant dispersal and hence, ultimately, to the risks to human health and environment. With regard to the first objective, the modelling work has been directed towards assessment of model reliability and asone aspect of this, a benchmarking exercise has been carried out. This paper briefly describes the benchmark scenario, the models developed and used, and discusses some of the benchmarking results. The role of the exercise within the modelling programme of IASAP will be discussed and future work described. 0 1997 Elsevier Science B.V.
Journal of Environmental Radioactivity, 2015
Dispersion Sediment Box models Hydrodynamic models a b s t r a c t Four radionuclide dispersion models have been applied to simulate the transport and distribution of 137 Cs fallout from Chernobyl accident in the Baltic Sea. Models correspond to two categories: box models and hydrodynamic models which solve water circulation and then an advection/diffusion equation. In all cases, interactions of dissolved radionuclides with suspended matter and bed sediments are included. Model results have been compared with extensive field data obtained from HELCOM database. Inventories in the water column and seabed, as well as 137 Cs concentrations along 5 years in water and sediments of several sub-basins of the Baltic, have been used for model comparisons. Values predicted by the models for the target magnitudes are very similar and close to experimental values. Results suggest that some processes are not very relevant for radionuclide transport within the Baltic Sea, for instance the roles of the ice cover and, surprisingly, water stratification. Also, results confirm previous findings concerning multi-model applications.
Transport and Fate of 137Cs Released From Multiple Sources in the North Atlantic and Arctic Oceans
Frontiers in Marine Science, 2021
The North Atlantic and Arctic oceans, along with the North Pacific, are the main reservoirs of anthropogenic radionuclides introduced in the past 75 years. The POSEIDON-R compartment model was applied to the North Atlantic and Arctic oceans to reconstruct 137Cs contamination in 1945–2020 due to multiple sources: global fallout, exchange flows with other oceans, point-source inputs in the ocean from reprocessing plants and other nuclear facilities, the impact of the Chernobyl accident and secondary contamination resulting from river runoff and redissolution from bottom sediments. The model simulated the marine environment as a system of 3D compartments comprising the water column, bottom sediment, and biota. The dynamic model described the transfer of 137Cs through the pelagic and benthic food chains. The simulation results were validated using the marine database MARIS. The calculated concentrations of 137Cs in the seaweed and non-piscivorous and piscivorous pelagic fish mostly foll...
Journal of Environmental Radioactivity, 1991
As a result of the Chernobyl fallout the Baltic Sea was the most affected marine ecosystem. The occurrence of 'hot spots' at the water surface was characteristic for the contamination. A one dimensional vertical dispersion model was used to explain the distribution of the radionuclides cesium 137 and cesium 134 in the water column of the central Bothnian Sea for the first six months after the contamination. In addition to the physical dispersion processes, specific chemical characteristics of the radionuclides were taken into consideration. During the time of siumulation, 5 per cent of the radionuclides cesium 137 and cesium 134 were trapped in the sediment, and 50 per cent of the plutonium 239/240 activity concentration was deposited, however, it's activity concentration measured in the water column was close to the limit of detection.
Calculation of artificial radionuclides in the ocean by an ocean general circulation model
2001
The concentrations of three artificial radionuclides (90 Sr, 137 Cs and 239+240 Pu) introduced into seawaters from global fallout were simulated from 1957 to 1994 by using an ocean general circulation model. The distributions of the calculated 137 Cs and 90 Sr concentrations were in good agreement with the observed concentrations. The vertical distribution of the calculated 239+240 Pu concentration in the South Pacific also agreed with the observed data. However, the calculated 239+240 Pu concentrations in the North Pacific water columns were significantly underestimated in comparison with the observed data, which strongly suggests the presence of additional sources of plutonium input to the North Pacific.
Three-dimensional model of radionuclide dispersion in estuaries and shelf seas
Environmental Modelling and Software, 1998
The 3-D model THREETOX was developed for the assessment of contamination in coastal seas and inland water bodies. It includes a high resolution numerical hydrodynamic submodel, a dynamic-thermodynamic ice submodel, and submodels for suspended sediment and pollution transport. The results of two case studies are described. The first case concerns a 2-year simulation of the Chernobyl radionuclide contamination of the Dnieper-Bug estuary to validate the model. In the second case study, simulations were performed for the assessment of the consequences of the possible release of radionuclides from scuttled reactors and containers with liquid radioactive wastes in the Novaya Zemlya fjords and the East Novaya Zemlya Trough of the Kara Sea. The simulated results demonstrated the capability of the THREETOX model to describe a wide spatial and temporal range of radionuclide transport processes in the ocean.
Collective doses to man from dumping of radioactive waste in the Arctic Seas
Science of The Total Environment, 1997
A box model for the dispersion of radionuclides in the marine environment covering the Arctic Ocean and the North Atlantic Ocean has been constructed. Collective doses from ingestion pathways have been calculated from unit releases of the radionuclides 3H, 6oCo, 63Ni, 90Sr, lz91, 137Cs, 239Pu and 241Am into a fjord on the east coast of NovayaZemlya. The results show that doses for the shorter-lived radionuclides (e.g. 137Cs) are derived mainly from seafood production in the Barents Sea. Doses from the longer-lived radionuclides (e.g. 239Pu) are delivered through marine produce further away from the Arctic Ocean. Collective doses were calculated for two release scenarios, both of which are based on information of the dumping of radioactive waste in the Barents and Kara Seas by the former Soviet Union and on preliminary information from the International Arctic Sea Assessment Programme. A worst-case scenario was assumed according to which all radionuclides in liquid and solid radioactive waste were available for dispersion in the marine environment at the time of dumping. Release of radionuclides from spent nuclear fuel was assumed to take place by direct corrosion of the fuel ignoring the barriers that prevent direct contact between the fuel and the seawater. The second scenario selected assumed that releases of radionuclides from spent nuclear fuel do not occur until after failure of the protective barriers. All other liquid and solid radioactive waste was assumed to be available for dispersion at the time of discharge in both scenarios. The estimated collective dose for the worst-case scenario was about 9 ma&v and that for the second scenario was about 3 manSv. In both cases 13'Cs is the radionuclide predicted to dominate the collective doses as well as the peak collective dose rates. 0 1967 Elsevier Science B.V.
Radioprotection, 2005
A linked chain of 1D river model RIVTOX and 3D estuary model THREETOX was used to assess impact of the previous and potential releases from the nuclear installations in the basins of Ob' and Yenisey rivers on radioactive contamination of the rivers and the Kara Sea. The RIVTOX includes the model of river hydraulics, suspended sediment and radionuclide transport in river channels. THREETOX includes a set of sub-models: a hydrodynamics sub-model, ice dynamics-thermodynamics sub-model, suspended sediment transport and radionuclide transport sub-models. The radionuclide transport model simulates processes in the water, suspended sediments and in bottom sediments. The simulations of the flux of 90 Sr and 137 Cs through the Ob' River and estuary from activities at the Mayak Production Association for the period 1949-1994 and through the Yenisey River and estuary from activities at the Mining, Chemical Combine for the period 1959-1994 were carried out. Based on scenarios, simulations have been performed in order to assess the potential risk of contamination from existing and potential sources of radionuclides into the Kara Sea through the Ob' and Yenisey rivers.
Science of The Total Environment, 1997
_---Russian-Norwegian expeditions to the Kara Sea and to dumping sites in the fjords of Novaya Zemlya have taken place annually since 1992. In the fjords, dumped objects were localised with sonar and ROV equipped with underwater camera. Enhanced levels of 13'Cs, 6oCo, "Sr and 23gX240Pu in sediments close to dumped containers in the Abrosimov and Stepovogo fjords demonstrated that leaching from dumped material has taken place. The contamination was inhomogeneously distributed and radioactive particles were identified in the upper 10 cm of the sediments. 137Cs was strongly associated with sediments, while 90Sr was more mobile. The contamination was less pronounced in the areas where objects presumed to be reactor compartments were located. The enhanced level of radionuclides observed in sediments close to the submarine in Stepovogo fjord in 1993 could, however, not be confirmed in 1994. Otherwise, traces of 6oCo in sediments were observed in the close vicinity of all localised objects. Thus, the general level of radionuclides in waters, sediments and biota in the fjords is, somewhat higher or similar to that of the open Kara Sea, i.e. significantly lower than in other adjacent marine systems (e.g. Irish Sea, Baltic Sea, North Sea). The main sources contributing to radioactive contamination were global fallout from atmospheric nuclear weapon tests, river transport from Ob and Yenisey, marine transport of discharges from Sellafield, UK and fallout from Chernobyl. Thus, the radiological impact to man and the arctic environment of the observed leakages from dumped radioactive waste today, is considered to be low. Assuming all radionuclides are released from the waste, preliminary assessments indicate a collective dose to the world population of less than 50 man Sv. 0 1997 Elsevier Science B.V. * Corresponding author. Tel.: + 47 64948350; fax: + 47 64948359 0048-9697/97/$17.00 0 1997 Elsevier Science B.V. All rights reserved. PII SOO48-9697(97) 00115-O 186 B. Salbu et al. / The Science of the Total Environment 202 II 947) 185 19X