On peculiarities of vertical distribution of 239,240 Pu, 238 Pu and 137 Cs activity concentrations and their ratios in lake sediments and soils (original) (raw)
Related papers
Plutonium Contamination in Soils and Sediments at Mayak Pa, Russia
Health Physics, 2005
The Mayak Production Association (Mayak PA) was established in the late 1940's to produce plutonium for the Soviet Nuclear Weapons Programme. In total, seven reactors and two reprocessing plants have been in operation. Today, the area comprises both military and civilian reactors as well as reprocessing and metallurgical plants. Authorized and accidental releases of radioactive waste have caused severe contamination to the surrounding areas. In the present study, ␣-spectrometry and inductively coupled plasma-mass spectrometry (ICP-MS) have been used to determine plutonium activities and isotope ratios in soil and sediment samples collected from reservoirs of the Techa River at the Mayak area and downstream Techa River. The objective of the study was to determine the total inventory of plutonium in the reservoirs and to identify the different sources contributing to the plutonium contamination. Results based on ␣-spectrometry and ICP-MS measurements show the presence of different sources and confirmed recent reports of civilian reprocessing at Mayak. Determination of activity levels and isotope ratios in soil and sediment samples from the Techa River support the hypothesis that most of the plutonium, like other radionuclides in the Techa River, originated from the very early waste discharges to the Techa River between 1949 and 1951. Analysis of reservoir sediment samples suggest that about 75% of the plutonium isotopes could have been released to Reservoir 10 during the early weapons production operation of the plant, and that the majority of plutonium in Reservoir 10 originates from discharges from power production or reprocessing. Enhanced 240 Pu/ 239 Pu atom ratios in river sediment upper layers (0-2 cm) between 50 and 250 km downstream from the plant indicate a contribution from other, non-fallout sources.
Lithuanian Journal of Physics
Vertical distributions of 239,240Pu and 137Cs activity concentrations in the waterlogged and non-boggy soil cores sampled in the vicinity of Vilnius City and in the Varėna District were analyzed. The radionuclides appeared in the soils mainly as a result of the fallout after the nuclear weapon testing in atmosphere in 1960s and due to the Chernobyl NPP accident in 1986. The deposited radionuclides on the surface of waterlogged soils on the shores of lakes experienced processes of translocation and accumulation, therefore their total activity in the column differs from the activity in non-boggy soils. The mobility of plutonium is the highest in waterlogged organic-rich soils. Clay in the waterlogged soil significantly limits the migration of radiocesium and does not affect noticeably the mobility of plutonium. Compared with radiocesium, the mobility of plutonium in non-boggy soils is somewhat limited. So, in waterlogged and non-boggy soils, the radionuclide mobilizing factors act in ...
Environmental behavior of plutonium isotopes studied in the area affected by the Chernobyl accident
The environmental behavior of Chernobyl-derived plutonium was reviewed in soil and aquatic environments in the affected areas of Ukraine. Dissolution of the released fuel particles marked the beginning of the migration in the environment for the Chernobyl-derived plutonium. Once dissolved, the plutonium distributed over the surface soil layer with low infiltration capacity. This relative immobility of plutonium in the soil environment is attributed to its affinity for soil organics, as suggested by previous studies of chemical partitioning. The relative immobility of plutonium was also seen in its fluvial transport along the Dnieper River. Dissolved organic matter, most probably humic substances, helped stabilize dissolved plutonium in the lake waters. Dissolved organic matter and purified humic substances in the area have been characterized for the fluorescence properties, molecular size distribution, functionality, and sources. Further analyses of the phase and chemical speciation of plutonium, taking into account the characterizations of matrices including humic substances, are needed to more fully understand the behavior of Chernobyl-derived plutonium, and to contribute to predict the migration of plutonium in other circumstances.
Radioprotection, 2002
The northeastern Poland is the area where fallout of Chernobyl 'fuel-like hot-particles" occurred. Experiment on the leaching out of radionuclides from forest litter was performed. Five samples were subsequently leached out by: a weak hydrochloric acid (fulvic acid fraction), ammonia water (humic acid fraction) and 2 M HCl (soluble fraction). Residue was analysed as well, after full mineralisation. Results on total activities and its distribution between fractions obtained for: l37 Cs, ^Sr, 239+240 Pu, I3 *Pu and M1 Am are presented. Relatively high activities of plutonium were observed in humic acid tractions. This founding support suggestions by other authors on possible complexing of Pu by humic acid.
Plutonium and thorium isotopes in the bottom sediments of some Mazurian Lakes (Poland)
Journal of Radioanalytical and Nuclear Chemistry, 2018
Presented are results on the Pu and Th isotopes activity concentration found in the upper part of bottom sediments collected from a deep part of 29 lakes in N-E Poland by diving in 2000. Analyses of Pu isotopic ratios allowed for the discussion of Pu origin. Maximum percentage of 239?240 Pu activity from Chernobyl fallout was 24%. Surface deposition of 239?240 Pu was calculated. No relationship was found between the plutonium and main chemical matrix components of sample nor with the trophic status of the lake. Pu activities were weakly correlated with measured previously 137 Cs activities.
Journal of Radioanalytical and Nuclear Chemistry, 2016
The paper summarizes results of investigation of the current state of radioactive contamination on site being under consideration for planned nuclear power plant in northern Poland. Thanks to use of sequential procedure it was possible to determine activity concentrations for radioisotopes of nine elements, both natural and artificial. Results show that observed levels of radioactive contamination are rather typical for central Europe and global fallout is dominant factor of presence of artificial radionuclides. The total deposition for artificial radionuclides revealed maxima equal to 1747 ± 121 Bq/m 2 for 137 Cs, 3854 ± 158 Bq/m 2 for 90 Sr, 101 ± 23 mBq/m 2 for 237 Np, 57.7 ± 6.0 Bq/m 2 for 241 Am, 3.27 ± 0.80 Bq/m 2 for 238 Pu and 68.5 ± 5.0 Bq/m 2 for 239?240 Pu.
Activity concentration of plutonium isotopes in bottom sediments and water in Crimean salt lakes
Journal of Radioanalytical and Nuclear Chemistry, 2020
The 238,239+240 Pu activity concentrations in sediments and in water in the Crimean salt lakes were studied. Activity ratio of 238 Pu/ 239+240 Pu in depth profiles of sediments was used to estimate the contribution of two main sources of man-made plutonium to the Pu sediment inventory. The most part of the plutonium was of global origin. Concentration factor of the plutonium isotopes in sediments, radiocapacity factor of the lake, the type of biogeochemical behavior of plutonium in these reservoirs and the sediment inventory of 238,239+240 Pu in the lakes were evaluated.
Man-made plutonium radioisotopes in the salt lakes of the Crimean peninsula
Journal of Oceanology and Limnology, 2018
Investigations of 239+240 Pu and 238 Pu in the surface layer (0-5 cm) of bottom sediment in the Crimean 10 salt lakes from 4 geographical groups were carried out for the fi rst time. The 239+240 Pu varied widely between regional geographical groups of lakes as well as within groups too and ranged from 11±4 to 451±43 mBq 239+240 Pu/kg. The highest levels of 239+240 Pu-419±27, 443±24 and 451±43 mBq/kg were observed in the Yevpatoriya (Lake Kyzyl-Yar), the Tarkhankut (Dzharylhach) and the Kerch group (Tobechik), respectively. The lowest values of 239+240 Pu were identifi ed in three lakes of the Perekop group and were 20±12, 24±6 and 48±6 mBq/kg. In all lakes 238 Pu was an order of magnitude lower than 239+240 Pu and varied from 4.8±2.6 to 30.7±5.5 mBq/kg. The 238 Pu activity was decay-corrected to 1986. The characteristic ratio of the 238 Pu/ 239+240 Pu activities in the sediment and percentage of the Chernobyl-derived Pu was calculated. The largest percentages of the Chernobyl-derived Pu were observed in the Evpatoriya group (Lake Sasyk-Sivash)-16.2%±8.26%, the Tarkhankut group (Dzharylhach)-8.4%±2.10% and the Kerch group (Aktash)-10.5%±5.56%. The study of the depth distribution of plutonium in the Lake Kyzyl-Yar bottom sediment core (0-25 cm) was fulfi lled. It was shown that 239+240 Pu was high enough in all studied layers of bottom sediment, but the highest activity ratio 238 Pu/ 239+240 Pu (0.062±0.020) was found in the deepest layer of 15-20.5 cm and the percentage of Chernobyl-derived Pu was estimated at 6.8%±2.85% in this layer.