カテゴリー「ecology・environment」
Title: The spatial variability of Chernobyl-derived 137Cs inventories in a small agricultural drainage basin in central Russia
Author: V.N. Golosov, D.E. Walling, A.V. Panin, E.D. Stukin, E.V. Kvasnikova, N.N. Ivanova
Reference: Applied Radiation and Isotopes, Volume 51, Issue 3, September 1999, Pages 341-352
DOI: http://dx.doi.org/10.1016/S0969-8043(99)00050-0
Keywords: Chernobyl; Radionuclides; Fallout; Caesium-137; Post-fallout redistribution
Abstract: Little information currently exists regarding the small-scale spatial variability of Chernobyl radiocaesium fallout and associated inventories. This contribution reports the results of a study of the variability of inventories within the 2.18-km2 Lapki balka catchment located near Tula in central Russia. The local area was characterized by inventories in excess of 200 kBq m−2 immediately after the Chernobyl accident and pre-existing bomb-derived inventories can be ignored in view of their very low magnitude. Field sampling and measurements included both collection of soil cores for subsequent laboratory analysis and in situ field measurements using a CORAD portable detector. The results obtained show evidence of a systematic south–north increase in the reference inventory across the basin, which must be taken into account when interpreting subsequent radiocaesium redistribution within the basin. Random spatial variability of inventories of a similar magnitude to that reported for bomb-derived fallout was also documented. The extent of random spatial variability varied between different geomorphological units. Maximum variability, with coefficients of variation up to 20%,was associated with areas of sediment accumulation within the balka bottoms. Substantial variability (cv. typically ca. 15%) was found within flat cultivated areas and undisturbed areas both on the interfluves and on the balka sides, all of which could serve as reference sites. Minimum variability (cv. typically ca. 12%) was associated with the cultivated slopes with no evidence of sediment accumulation.
URL: http://www.sciencedirect.com/science/article/pii/S0969804399000500
Title: Development of requirements for environmental specimen banking in ecological monitoring (exemplified by the Chernobyl NPP accident area)
Author: V.A. Borzilov
Reference: Science of The Total Environment, Volumes 139–140, 1 November 1993, Pages 197-201
DOI: http://dx.doi.org/10.1016/0048-9697(93)90019-3
Keywords: data bank; accident area; Chernobyl NPP; ecological monitoring
Abstract: Development of requirements for a data bank for natural media as a system of intercorrelated parameters to estimate system states are determined. The problems of functional agreement between experimental and calculation methods are analysed when organizing the ecological monitoring. The methods of forming the environmental specimen bank to estimate and forecast radioactive contamination and exposure dose are considered to be exemplified by the peculiarities of the spatial distribution of radioactive contamination in fields. Analysed is the temporal dynamics of contamination for atmospheric air, soil and water.
URL: http://www.sciencedirect.com/science/article/pii/0048969793900193
Title: Radiological effects on populations of Oligochaeta in the Chernobyl contaminated zone
Author: V.G. Tsytsugina, G.G. Polikarpov
Reference: Journal of Environmental Radioactivity, Volume 66, Issues 1–2, 2003, Pages 141-154
DOI: http://dx.doi.org/10.1016/S0265-931X(02)00120-0
Keywords: Oligochaeta; The Chernobyl NPP accident; Reproduction; Chromosome aberrations
Abstract: A detailed investigation of 3 populations of Oligochaete species (Dero obtusa, Nais pseudobtusa and Nais pardalis) has been carried out in a contaminated lake of the close-in Chernobyl zone and in a control lake. Hydrochemical indices and concentrations of heavy metals, chloro-organic compounds and 90Sr in bottom sediments have been measured. Absorbed doses were calculated on the basis of the results of radiochemical analysis and assessed directly with thermoluminescent dosimeters (TLD). Stimulation of paratomous division (asexual reproduction) was found in one species of worm (D. obtusa), and activation of sexual reproduction in the two other species studied. An increase in the amount of cytogenetic damage in the somatic cells of worms from the contaminated lake was found and an attempt was made to assess the relative contributions of radiation and chemical exposure on the basis of analyses of inter-cellular aberration distributions and the types of chromosome aberrations observed in the cells.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X02001200
Title: The role of soil erosion and fluvial processes in the post-fallout redistribution of Chernobyl-derived caesium-137: a case study of the Lapki catchment, Central Russia
Author: A.V Panin, D.E Walling, V.N Golosov
Reference: Geomorphology, Volume 40, Issues 3–4, October 2001, Pages 185-204
DOI: http://dx.doi.org/10.1016/S0169-555X(01)00043-5
Keywords: Chernobyl; Caesium-137; Redistribution; Fluvial processes; Sediment; Soil erosion; Deposition
Abstract: The central area of the Russian Plain received substantial amounts Cs-137 fallout as a result of the Chernobyl accident in 1986, with inventories exceeding 40 kBq m−2 in many of the areas close to Chernobyl. Concern over the longer-term fate of this contamination has focused attention on the need to predict the post-fallout redistribution of the radiocaesium and, thus, future changes in the spatial distribution of contamination in the landscape. Since radiocaesium reaching the land surface as fallout is rapidly and strongly adsorbed by soil and sediment particles, any attempt to predict its post-fallout redistribution must focus on erosion and sediment delivery processes and must rely heavily on a knowledge of the geomorphological processes involved. This paper reports a detailed investigation of post-fallout Cs-137 redistribution in the 2.18-km2 Lapki catchment in the Middle-Russian Upland, which has required consideration of soil erosion processes, sediment delivery pathways, sediment delivery ratios and sediment sinks. The time elapsed since the Chernobyl accident is currently insufficient to result in significant reduction of Cs-137 inventories in eroding areas, but areas of deposition on both the lower slopes and on the balka sides and bottoms are already marked by significant increases in Cs-137 inventories. The results obtained emphasise that any attempt to develop meaningful predictions of the longer-term redistribution of Chernobyl-derived Cs-137 fallout within the Russian Plain must be based on a sound and detailed understanding of the linkage between the slopes and the balka systems and the fate of sediment entering the balka systems.
URL: http://www.sciencedirect.com/science/article/pii/S0169555X01000435
Title: Characteristics of Chernobyl-derived radionuclides in particulate form in surface waters in the exclusion zone around the Chernobyl Nuclear Power Plant
Author: Takeshi Matsunaga, Takashi Ueno, Hikaru Amano, Y Tkatchenko, A Kovalyov, Miki Watanabe, Yoshikazu Onuma
Reference: Journal of Contaminant Hydrology, Volume 35, Issues 1–3, 15 December 1998, Pages 101-113
DOI: http://dx.doi.org/10.1016/S0531-5131(01)00601-X
Keywords: Chernobyl; Transuranic elements; Cs-137; Sr-90; Surface water body; Partitioning; Distribution ratio
Abstract: The distribution of Chernobyl-derived radionuclides in river and lake water bodies at 6–40 km from the Chernobyl Nuclear Power Plant was studied. Current levels of radionuclides (Cesium-137, Strontium-90, Plutonium, Americium and Curium isotopes) in water bodies and their relation to the ground contamination are presented. The investigation of the radionuclide composition of aqueous and ground contamination revealed that radionuclides on suspended solids (particulate form) originate mainly from the erosion of the contaminated surface soil layer in the zone. Apparent distribution ratios between particulate and dissolved forms are compared to known distribution coefficients.
URL: http://www.sciencedirect.com/science/article/pii/S0169772298001193
Title: I-129 and I-131 ground deposition densities are correlated in Belorussian settlements contaminated following the Chernobyl accident
Author: Masaharu Hoshi, Valery F Stepanenko, Yuri I Gavrilin, Yuri M Volkov, Irina K Makarenkova, Jun Takada, Valery E Shevchuk, Valery G Skvortsov, Dmitry V Petin, Elena K Iaskova, Alexey E Kondrashov, Alexander I Ivannikov, Nataly M Ermakova, Leonid N Chunikhin
Reference: International Congress Series, Volume 1234, May 2002, Pages 115-120
DOI: http://dx.doi.org/10.1016/S0531-5131(01)00601-X
Keywords: Chernobyl accident; I-129; I-131; Thyroid dose
Abstract: Long-living I-129 is considered as the witness of short-living I-131 fallout following the Chernobyl accident. Data on I-129 deposition densities might help to estimate thyroid doses in population of many contaminated areas where information on the I-131 ground deposition density is unknown.
This pilot study aimed to investigate the correlations between I-129 ground deposition densities measured in 2000 and those of I-131 measured in 1986.
I-129 measurements were performed by iodine separation and registration of I-129 decays using beta-x coincidence. Soil samples were collected and I-129, Cs-137 ground deposition densities were measured in three contaminated raions of Belorussia (14 locations in 12 settlements). For 10 of 12 settlements, there were available data of I-131 and Cs-137 spectrometric measurements during the first weeks after the accident in 1986.
Results of I-129 and Cs-137 measurements in 2000 were used for the reconstruction of I-131/Cs-137 ratio. Comparisons of reconstructed I-131/Cs-137 ratios with the I-131/Cs-137 ratios obtained by direct measurements in 1986 showed good agreement: correlation coefficient was 0.69 and linear regression coefficient (±SD) was 2.36(±0.88). The study confirms the possibility to apply the data on I-129 ground deposition densities for further application to improve estimations of thyroid absorbed doses, which result from I-131 irradiation.
URL: http://www.sciencedirect.com/science/article/pii/S053151310100601X
Title: Mapping of 137Cs deposition over eastern France 16 years after the Chernobyl accident
Author: Philippe Renaud, Laurent Pourcelot, Jean-Michel Métivier, Marcel Morello
Reference: Science of The Total Environment, Volume 309, Issues 1–3, 20 June 2003, Pages 257-264
DOI: http://dx.doi.org/10.1016/S0048-9697(03)00049-4,
Keywords: Chernobyl; 137Cs; Depositions mapping; France
Abstract: We observed the relationship between present-day 137Cs surface activity and the rainfall in May 1986 to establish a relevant map of 137Cs deposition over eastern France. This study was performed in an area of the lower Rhône valley where clayey soils are assumed to trap caesium efficiently. Based on the rainwater/airborne activity ratio deduced from this relationship, we verified that present-day activities, measured in clayey soils of this type, are relatively representative of the initial depositions. The interlocked contaminated areas of the resulting map can be related to rainfall occurrences, as is the case for all countries affected by the Chernobyl fallout. This map can be reasonably compared with those obtained for countries bordering France in terms of both activity levels and extent of homogeneous activity areas. Lastly, we demonstrate that it would not be possible to produce a coherent map of initial fallout by extending the campaign over the whole of the eastern territory based on present-day soil activity measurements alone. Hence, only the relationship between 137Cs deposition and the rainfall of the first week of May 1986 can be used to construct a map depicting the Chernobyl fallout over eastern France.
URL: http://www.sciencedirect.com/science/article/pii/S0048969703000494
Title: 137Cs distribution among annual rings of different tree species contaminated after the Chernobyl accident
Author: N.V Soukhova, S.V Fesenko, D Klein, S.I Spiridonov, N.I Sanzharova, P.M Badot
Reference: Journal of Environmental Radioactivity, Volume 65, Issue 1, 2003, Pages 19-28
DOI: http://dx.doi.org/10.1016/S0265-931X(02)00061-9
Keywords: Chernobyl; Radioactivity; Radionuclides; Betula pendula; Pinus sylvestris; Radiocaesium; Tree rings; Radial distribution
Abstract: The distributions of 137Cs among annual rings of Pinus sylvestris and Betula pendula at four experimental sites located in the most contaminated areas in the Russian territory after the Chernobyl accident in 1986 were studied. Trees of different ages were sampled from four forest sites with different tree compositions and soil properties. The data analysis shows that 137Cs is very mobile in wood and the 1986 rings do not show the highest contamination. The difference between pine and birch in the pattern of radial 137Cs distribution can be satisfactorily explained by the difference in radial ray composition. 137Cs radial distribution in the wood can be described as the sum of two exponential functions for both species. The function parameters are height, age and species dependent. The distribution of 137Cs in birch wood reveals much more pronounced dependence on site characteristics and/or the age of trees than pines. The data obtained can be used to assess 137Cs content in wood.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X07000252
Title: Long-term investigations of radiocaesium activity concentrations in carp in North Croatia after the Chernobyl accident
Author: Zdenko Franić, Gordana Marović
Reference: Journal of Environmental Radioactivity, Volume 94, Issue 2, May 2007, Pages 75-85
DOI: http://dx.doi.org/10.1016/j.jenvrad.2007.01.001
Keywords: Carp; Concentration factor; 137Cs; 134Cs; Chernobyl accident; Dose; Fish consumption
Abstract: Long-term investigations of radiocaesium activity concentrations in carp in the Republic of Croatia are presented. The radiocaesium levels in carp decreased exponentially and the effective ecological half-life of 137Cs was estimated to be about 1 year during 1987–2002 and 5 years during 1993–2005.
The observed 134Cs:137Cs activity ratio in carp was found to be similar to the ratio observed in other environmental samples.
The concentration factor for carp (wet weight) was estimated to be 128 ± 74 L kg−1, which is in reasonable agreement with model prediction based on K+ concentrations in water.
Estimated annual effective dose received by adult members of the Croatian population due to consumption of carp contaminated with 134Cs and 137Cs are small: per capita dose from this source during 1987–2005 was estimated to be 0.5 ± 0.2 μSv.
Due to minor freshwater fish consumption in Croatia and low radiocaesium activity concentrations in carp, it can be concluded that carp consumption was not a critical pathway for the transfer of radiocaesium from fallout to humans after the Chernobyl accident.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X07000252
Title: Distribution of pre- and post-Chernobyl radiocaesium with particle size fractions of soils
Author: Pasquale Spezzano
Reference: Journal of Environmental Radioactivity, Volume 83, Issue 2, 2005, Pages 117-127
DOI: http://dx.doi.org/10.1016/j.jenvrad.2005.02.002
Keywords: Chernobyl fallout; Weapons fallout; Soil; Radiocaesium; Particle size distribution
Abstract: The association of radiocaesium with particle size fractions separated by sieving and settling from soils sampled eight years after the Chernobyl accident has been determined. The three size fractions were: 63 μm. 137Cs in the soil samples was associated essentially with the finer size fractions, which generally showed specific activities 3–5 times higher than the bulk samples.
Activity ratios of 134Cs/137Cs in the clay-sized fractions appear to be lower with respect to the corresponding values in bulk soil samples. This result indicates that some differences still exists in the particle size distribution between 137Cs originating from nuclear weapons, which has been in the soil for decades after fallout, and 137Cs coming from the Chernobyl accident, eight years after the deposition event. This behaviour could be related to “ageing” processes of radiocaesium in soils.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X05000548
