Vertical distribution of anthropogenic radionuclides in cores from contaminated floodplains of the Yenisey River (original) (raw)
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Journal of Geochemical Exploration, 2014
Eu Radionuclide burial patterns Landscape-radiometric survey and soil sampling performed in the islands of Beriozovy and Balchug (20 km downstream the Krasnoyarsk Mining and Chemical Combine), and in the Mikhin Island (180 km downstream) showed that the distribution of technogenic radionuclides depends upon the history of contamination and landscape features of the floodplain. Contamination densities of 137 Cs appeared to be significantly higher than could be expected from global fallout (1.75-2.5 kBq/m 2 ): in 2000 the maximum value for 137 Cs in the Beriozovy Island equaled 663 kBq/m 2 , in the Balchug site -577 kBq/m 2 and in the Mikhin Island -518 kBq/m 2 ). 137 Cs contamination density was practically independent of the remoteness from the KMCC that proved its considerable migration in the water-soluble or fine particulate forms. Vertical distributions of man-made nuclides in soil cores depended upon the different half-life of the studied radionuclides, the soil profile relative altitude, its structure and texture. The two main burial depths of 137 Cs activity depended upon the intensity of sedimentation and varied from 5 cm to 20-25 cm. In 2000 maximum contamination by 60 Co and 152,154 Eu isotopes was associated with the top layer and decreased exponentially with depth. Obtained data is believed to be important for ecological monitoring of the flood plains subjected to radionuclide contamination. (E.M. Korobova), Justin.Brown@nrpa.no (J. Brown), potapov_v@mail.ru (V.N. Potapov).
Water Quality, 2017
The Yenisei River is one of the largest rivers in the world. There is Mining and Chemical Combine (MCC) of Rosatom located at Krasnoyarsk, on the bank of the River Yenisei, 50 km downstream of the city of Krasnoyarsk. Since 1958 MCC used river's water for cooling of industrial nuclear reactors for the production of weapon plutonium-238 Pu. Besides the pollution caused by industry-related radionuclides, pollution by natural radionuclide-uranium and its isotopes-are also investigated. Besides the natural uranium isotopes (234 U, 235 U, 238 U), exclusive artificial isotope-236 U was also found. Yenisei water was also polluted by high tritium content: from 4 Bq/L (back road value) to 200 Bq/L (some sample of water). The total amount of radionuclides investigated was about 20 radioisotopes. These radionuclides have different physical and chemical properties, different half-lives, and so on. Thus, the data on artificial radionuclides entering the Yenisei River water were obtained by long-term monitoring, which is likely to be connected with the activity of the industrial enterprises located on the river's banks of the studied area.
Radioprotection, 2002
The results of the retrospective global radioactive contamination mapping of the Enisey-river catchment are presented. The maps of spatial ,J7 Cs distributions of 1964, 1974, 1986, 2000 are compiled using the geoinformation technologies in the Institute of Global Climate and Ecology. The territory of mapping is 2600000 km 2. The mapping is done from the airbome-gamma-spectrum data obtained at the beginning of 1960, of 1970 and 1990. In 2000 the global levels of IJ7 Cs are 0.4-3 kBq/m J. A small contribution of Chernobyl deposition can be registered on the maps built later 1986 (0.02-0.15 kBq/m :). The levels of 2.5-3 kBq/m 1 in the region of Severo-Eniseyski and Teya localities can be estimated as the tail part of the eastern Chernobyl partem. The present levels of 2.59-122 kBqVm 2 are observed on the Enissey valley at distances of 0-1700 km from Krasnoyarsk-26. The parameters of runoff and soil erosion are estimated using the cartographic information, provided by the Laboratory of River Processes and Soil Erosion of the Moscow State University. A part of 137 Cs, accumulated in the Enisey-valley from early 1960 to 2000 with the transport of soil material from interfluve of all Enisey tributaries, will be estimated using a balance model of soil erosion. The contribution of IJT Cs from the catchment to the valley is estimated with respect to total l37 Cs deposited in the valley.
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.
Environmental Geology, 2004
Total concentrations of 13 elements (K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Y, Zr, Pb) in the size-fractionated Sava River sediments upstream and downstream of the Krsko nuclear power plant together with metal speciation within bulk sediment have been investigated. Trace metals generally increase with decreasing particle size, however, because of entrapment of organic matter in the 0.63-1 mm fraction, concentrations in the coarser sediment fraction are higher than expected. Exchangeable Pb, Zn, Cu, Mn, Cr and Fe are generally found to represent a negligible fraction of the total metal concentration of the bulk sediment. Seasonal variations of the Pb, Zn and Cu concentrations in the <0.5 mm fraction reflect decreased values during the spring period. Heavy metal concentrations in the 2003 waste water discharges from the Krsko nuclear power plant released into the Sava River were much lower than their maximum allowed values. Combined rubidium and organic matter normalization of the Zn, Pb and Cu concentrations, which was applied on the minus 0.063 mm fraction, indicated three potential sources of contaminants.
Association of plutonium with sediments from the Ob and Yenisey Rivers and Estuaries
Journal of Environmental Radioactivity, 2009
The present study applied sequential extraction techniques to investigate the binding and mobility of plutonium (Pu) in sediments from the rivers and estuaries of the Ob and Yenisey. As a study site, the Ob and Yenisey are particularly interesting as both rivers have weapons-grade Pu sources in their catchment areas, including the Russian Pu production and reprocessing plants at Mayak, Tomsk-7 and Krashnoyarsk, and the Semipalantinsk nuclear weapons testing site in Kazakhstan. Plutonium activity and 240 Pu/ 239 Pu ratios were determined using accelerator mass spectrometry (AMS). Sequential extractions showed that between 47 and 80% of the Pu in Yenisey River sediments and 35-53% of the Pu in soils around the Techa River are mobilized with weak oxidising agents, which can indicate that Pu is bound to organic material. In contrast, Pu in Ob and Yenisey Estuarine sediments was more strongly bound, with 60-100% being found in the HNO 3 -extractable fraction. This change in speciation could reflect either that Pu bound to organic material in the Techa and Yenisey River sediments becomes more fixed to the sediments with time, or that organic-bound Pu is mobilized and released to the water when the sediments encounter the more saline water of the Ob and Yenisey estuaries. In general, 240 Pu/ 239 Pu ratios were relatively consistent between different extraction fractions, although, in whole sediments, an increase in ratio was observed with distance from the source. This reflects the increased influence of weapon fallout from catchment runoff within the river systems, as compared to the weapons-grade sources close to the production and reprocessing plants. Knowledge of Pu speciation in the Ob and Yenisey Rivers, and the processes controlling its behaviour in estuarine systems, can improve predictions of its transfer and subsequent environmental impact to Arctic Seas.
Radioactive pollution of the Ob river system from urals nuclear enterprise ‘MAJAK’
Journal of Environmental Radioactivity, 1994
The Techa river belongs to the Iset Tobol-Irtysh-Ob river system. Around 1950 the Techa was contaminated with medium and high level radioactive waste Ji'om the MAJAK nuclear installation. The total discharge amounted to 100 PBq: 9°Sr and WCs contributed 11"6% and 12"2% respectively. Presentl)' the Techa contains about 0"3 TBq 9°Sr, more than 6 TBq ]~T Cs and about 8 GBq 23°'24t)pu. The levels o]" the radionuclides upstreanl are several orders o[magnitude higher than those expected[?om globalJ'allout. The activit.r concentrations decrease exponentially or by power functions with distance. The study has shown that the contamination of the soil ¢?[ the Techa JTood plain is 15-85 times higher than globaljitllout levels. There is an unexplained radioactive contamination in the lset river qfter con/hwnce with the Techa.
Applied Radiation and Isotopes, 1995
The major sources of plutonium isotopes in the environment are from nuclear weapons testing via global and close-in (debris) fallout, nuclear fuel reprocessing and fabrication plant effluents. Measurements of differences in the Pu isotopic ratios (239pu/z4°pu, 23sPu/239.~4°Pu and 24~pu/239.2~Pu) have yielded information not only on the time horizons for sedimentary deposits but also on the sources of Pu. We have measured 23sPu, 239.24°pu and ~37Cs concentrations in the surlicial sediments of the Ob and Yenisey Rivers (Russia) and the Kara Sea. The downcore variations of 23sPu and 239.24°Pu concentrations have also been measured in some sediment cores. A comparison of the sediment core inventories of 239' 24°Pu along with the 23spu/239'24°pu activity ratios with those expected from global fallout at the study sites allows us to estimate the relative amounts of reactor-derived 23sPu and 239.2~Pu from the dumped reactor sites in the study area. In surficial sediment samples, the 239.24°Pu concentrations vary between 9.4 and 627 mBq kg -~, with a mean of 250 mBq kg ~.