カテゴリー「ecology・environment」
Title: Radioactivity measurements in air over Europe after the Chernobyl accident
Author: Frank Raes, Giovanni Graziani, David Stanners, Franco Girardi
Reference: Atmospheric Environment. Part A. General Topics, Volume 24, Issue 4, 1990, Pages 909-916
DOI: http://dx.doi.org/10.1016/0960-1686(90)90293-V
Keywords: Chernobyl; air concentrations; LRT; Cs-134/Cs-137
Abstract: A comprehensive European data set of radioactivity in air caused by the accident at the Chernobyl nuclear power plant is presented. For the first 2 weeks after the beginning of the release, levels of particulate I-131, Cs-134 and Cs-137 (85 locations) and of total I-131 (10 locations) are given. All data are stored in a computerized data base. For the first time the passage of the Chernobyl cloud over Europe is mapped after re-averaging the time histories in each location to produce coherent daily concentrations. Cs-134/Cs-137 ratios were analyzed: the ‘European’ average ratio calculated from 1239 samples is 0.55, with a standard deviation of 0.25.
URL: http://www.sciencedirect.com/science/article/pii/096016869090293V
Title: Radiocesium in muscle tissue of reindeer and pike from northern Sweden before and after the Chernobyl accident. A retrospective study on tissue samples from the Swedish Environmental Specimen Bank
Author: Sevald Forberg, Tjelvar Odsjö, Mats Olsson
Reference: Science of The Total Environment, Volume 115, Issue 3, 30 April 1992, Pages 179-189
DOI: http://dx.doi.org/10.1016/0048-9697(92)90328-P
Keywords: radiocesium; reindeer; pike; Chernobyl; environmental specimen bank
Abstract: After the Chernobyl accident in April 1986, considerable deposition of radionuclides occurred regionally in eastern, central and northwestern Sweden. Locally, the fallout of radiocesium exceeded the remainder from atmospheric nuclear weapons tests by several magnitudes. Since the end of the 1960s samples of organs from various plant and animal species, annually collected at different localities, have been preserved in the Swedish Environmental Specimen Bank (ESB). In this work samples from the ESB have been used for retrospective studies of radioactive pollution. The activities of Cs-134 and Cs-137 in muscle tissues from reindeer, Rangifer tarandus, and pike, Esox lucius, preserved in the ESB, were measured. The samples were collected annually; the reindeer at three localities in northern Sweden and the pike at one of them. In material collected prior to the Chernobyl accident, the levels of Cs-137 were 57–180 Bq/kg in reindeer and 14–24 Bq/kg in pike, fresh weight basis. These levels relate to earlier nuclear bomb tests. A significant decrease was found in pike during the pre-Chernobyl period (1971–1986). In post-Chernobyl samples the burden of Cs-137 varied from amounts equal to the former levels in the northernmost locality and up to 80 times higher for the maximum values in the southernmost locality. The highest value recorded was 18 425 Bq/kg in reindeer. The geographic variations in reindeer from Chernobyl fallout were in accordance with the pattern of deposition estimated by aircraft surveys performed in May 1986. The ratio between ‘new’ and ‘old’ radiocesium burdens in pike, caught in 1987, approached the corresponding ratio for reindeer grazing in the precipitation area of the lake; 33 and 19, respectively.
URL: http://www.sciencedirect.com/science/article/pii/004896979290328P
Title: Rural areas affected by the Chernobyl accident: Radiation exposure and remediation strategies
Author: P. Jacob, S. Fesenko, I. Bogdevitch, V. Kashparov, N. Sanzharova, N. Grebenshikova, N. Isamov, N. Lazarev, A. Panov, A. Ulanovsky, Y. Zhuchenko, M. Zhurba
Reference: Science of The Total Environment, Volume 408, Issue 1, 15 December 2009, Pages 14-25
DOI: http://dx.doi.org/10.1016/j.scitotenv.2009.09.006
Keywords: Caesium; Chernobyl; Ionizing radiation; Rehabilitation; Remediation
Abstract: Main objectives of the present work were to develop an internationally agreed methodology for deriving optimized remediation strategies in rural areas that are still affected by the Chernobyl accident, and to give an overview of the radiological situation in the three affected countries, Belarus, Russia and Ukraine. Study settlements were defined by having in 2004 less than 10,000 inhabitants and official dose estimates exceeding 1 mSv. Data on population, current farming practices, contamination of soils and foodstuffs, and remedial actions previously applied were collected for each of such 541 study settlements. Calculations of the annual effective dose from internal radiation were validated with extensive data sets on whole body counter measurements. According to our calculations for 2004, in 290 of the study settlements the effective dose exceeded 1 mSv, and the collective dose in these settlements amounted to about 66 person-Sv. Six remedial actions were considered: radical improvement of grassland, application of ferrocyn to cows, feeding pigs with uncontaminated fodder before slaughter, application of mineral fertilizers for potato fields, information campaign on contaminated forest produce, and replacement of contaminated soil in populated areas by uncontaminated soil.
URL: http://www.sciencedirect.com/science/article/pii/S004896970900850X
Title: The effective source area of 90Sr for a stream near Chernobyl, Ukraine
Author: Rina Freed, Leslie Smith, Dmitri Bugai
Reference: Journal of Contaminant Hydrology, Volume 71, Issues 1–4, July 2004, Pages 1-26
DOI: http://dx.doi.org/10.1016/j.jconhyd.2003.07.002
Keywords: Chernobyl; Hydrologic contaminant transport; Non-point source; Soil contamination; Strontium-90
Abstract: Remediation of streams impacted by non-point source contaminants requires an understanding of both the areas within a watershed that are contributing contamination to streams and the pathways of contaminant migration to streams. From 1998 to 2002, we studied the migration of 90Sr in the Borschi watershed, a small (8.5 km2) catchment three km south of the Chernobyl Nuclear Power Plant, Ukraine. Fuel particles, distributed in a heterogeneous pattern across the watershed, are weathering and releasing 90Sr from the fuel matrix. Depletion of 90Sr, evaluated in comparison to the immobile fission product europium-154, is occurring in the channel and wetland sediment. Channel sediments are uniformly depleted in 90Sr with depth. In wetland sediments, there is a zone of depletion in the top10 cm and a zone of accumulation at depths from 10 to 25 cm. Estimates of 90Sr depletion are used to map the effective source area that has contributed 90Sr loading to the main channel. The effective source area includes channel bottom sediments, a wetland in the central region of the watershed, and periodically flooded soils surrounding the wetland. The total depletion from the effective source area is estimated to be 36±7×1010 Bq. Based on observations of stream flow rate and water quality in 1999–2001, the annual 90Sr removal rate from the watershed is estimated to be 1.4±0.2×1010 or 1.5% of the inventory per year. When extrapolated over a 15-year period following the Chernobyl accident, the last value is in reasonable agreement with the estimated depletion of the source area based on 90Sr/154Eu ratios. The 90Sr yearly leaching rate considering the whole watershed is 0.2% while the 90Sr leaching rate considering the effective source area is an order of magnitude higher. Most of the 90Sr release in the watershed has originated from an effective source area of 0.62 km2, or 7% of the watershed area.
URL: http://www.sciencedirect.com/science/article/pii/S0169772203002225
Title: Countermeasures in agricultural production as an effective means of mitigating the radiological consequences of the Chernobyl accident
Author: R.M. Alexakhin
Reference: Science of The Total Environment, Volume 137, Issues 1–3, 2–4 September 1993, Pages 9-20
DOI:http://dx.doi.org/10.1016/0048-9697(93)90374-F
Keywords: Chernobyl accident; agriculture; caesium-137; radioactive contamination; countermeasures
Abstract: In the wake of the Chernobyl accident of 1986, the implementation of a variety of protective measures in agriculture has been the most effective means of reducing the total radiation dose of the population; reduction of external radiation by soil decontamination is much less cost effective. As a result of the agricultural countermeasures, internal doses have been decreased by a factor of approximately three. In Russia, these countermeasures resulted in a decrease of 137Cs accumulation in arable crops by a factor of about 2.3 and in pastures of about 2.8. Reduction of radiocaesium in herbage is one of the most importance factors, since this results in a reduction of 137Cs in milk — the main source of radiation dose in the human diet. Countermeasures used on grazing land included ploughing, liming, application of fertilisers etc. 137Cs in plant crops can be decreased 5–10 times by changing the type of crops cultivated. In natural meadows and pastures and on arable soils without the benefit of treatment, it has been observed that plant uptake of 137Cs decreased with time. The efficiency of different protective measures in agriculture has been assessed in the accident-affected zone.
URL: http://www.sciencedirect.com/science/article/pii/004896979390374F
Title: Concentration levels of technetium-99 in forest soils collected within the 30-km zone around the Chernobyl reactor
Author: S Uchida, K Tagami, E Wirth, W Rühm
Reference: Environmental Pollution, Volume 105, Issue 1, April 1999, Pages 75-77
DOI:http://dx.doi.org/10.1016/S0269-7491(98)00210-3
Keywords: Technetium-99; Chernobyl accident; Forest soil; Cesium-137; ICP-MS
Abstract: Technetium-99 (99Tc) concentrations in surface soil samples collected from three forest sites within the 30-km zone around the Chernobyl reactor were determined. A simple and rapid analytical method, which consists of volatilizing and trapping Tc in a combustion apparatus, purifying the Tc with an extraction chromatographic resin and measuring it by ICP-MS, was used for the determination. The concentrations of 99Tc in the samples ranged from 1.1 to 14.1 Bq kg−1 on an air-dried soil basis. The activities of the nuclide in the soils around the Chernobyl reactor were one or two orders of magnitude higher than in other areas which were less affected by the accident. The activity ratios of 99Tc/137Cs ratios in the soils were calculated as on the order of 3.7×10−5 to 1.3×10−4.
URL: http://www.sciencedirect.com/science/article/pii/S0269749198002103
Title:Plutonium, 137Cs and 90Sr in selected invertebrates from some areas around Chernobyl nuclear power plant
Author: Jerzy W. Mietelski, Svetlana Maksimova, Przemysław Szwałko, Katarzyna Wnuk, Paweł Zagrodzki, Sylwia Błażej, Paweł Gaca, Ewa Tomankiewicz, Olexandr Orlov
Reference: Journal of Environmental Radioactivity, Volume 101, Issue 6, June 2010, Pages 488-493
DOI:http://dx.doi.org/10.1016/j.jenvrad.2008.04.009
Keywords: Plutonium; 90Sr; 137Cs; Chernobyl; Invertebrates; Radioactive contamination of biota
Abstract: Results are presented for 137Cs, 90Sr and plutonium activity concentrations in more than 20 samples of terrestrial invertebrates, including species of beetles, ants, spiders and millipedes, collected in the highly contaminated area of the Chernobyl exclusion zone. The majority of samples were collected in Belarus, with some also collected in the Ukraine. Three other samples were collected in an area of lower contamination. Results show that seven samples exceed an activity concentration of 100 kBq/kg (ash weight – a.w.) for 137Cs. The maximum activity concentration for this isotope was 1.52 ± 0.08 MBq/kg (a.w.) determined in ants (Formica cynerea). Seven results for 90Sr exceeded 100 kBq/kg (a.w.), mostly for millipedes. Relatively high plutonium activity concentrations were found in some ants and earth-boring dung beetles. Analyses of activity ratios showed differences in transfer of radionuclides between species. To reveal the correlation structure of the multivariate data set, the Partial Least-Squares method (PLS) was used. Results of the PLS model suggest that high radiocesium activity concentrations in animal bodies can be expected mainly for relatively small creatures living on the litter surface. In contrast, high strontium activity concentrations can be expected for creatures which conduct their lives within litter, having mixed trophic habits and a moderate lifespan. No clear conclusions could be made for plutonium.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X08000696
Title: The chernobyl accident: Modelling of dispersion over europe of the radioactive plume and comparison with air activity measurements
Author: Armand Albergel, Daniel Martin, Bernard Strauss, Jean-Michel Gros
Reference: Atmospheric Environment (1967), Volume 22, Issue 11, 1988, Pages 2431-2444
DOI:http://dx.doi.org/10.1016/0004-6981(88)90475-1
Keywords: Long-range; modelling; radioisotopes; caesium; Chernobyl; nuclear; accident; trajectories; dispersion
Abstract: Following the release of radionuclides from the Chernobyl power plant accident, a long-range transport and deposition model is used to describe the plume dispersion over Europe. The aim of this study is the validation of a fast Lagrangjan model and a better understanding of the relative impact of some mechanisms, such as the initial plume rise. Comparisons between results and 137Cs measurement activity are discussed according to spatial and temporal variations. It is shown that many measurements can be explained only if the initial plume rise taken at 925, 850 and 700mb is considered.
URL:http://www.sciencedirect.com/science/article/pii/0004698188904751
Title: Fractal fluctuation of aerosol concentration near Chernobyl
Author: Y. Hatano, N. Hatano
Reference: Atmospheric Environment, Volume 31, Issue 15, August 1997, Pages 2297-2303
DOI:http://dx.doi.org/10.1016/S1352-2310(97)00017-4
Keywords: Aerosol; Chernobyl; fluctuation; fractal; correlation; theoretical model; diffusion
Abstract: We present a simple model of aerosol migration with fractal, or self-similar fluctuation of wind speed. The purpose of the study is to explain fractal fluctuation of airborne radionuclide concentration which was measured daily near Chernobyl by Garger et al. Our theoretical prediction on the concentration fluctuation agrees with the measured data remarkably. We also predict that the mean concentration decreases in time as , where λ denotes the sum of constants of the first-order kinetics, such as the radioactive decay rate and the chemical reaction rate. It is suggested that the characteristics of fluctuation appearing in our model are universal for large-scale atmospheric pollution.
URL: http://www.sciencedirect.com/science/article/pii/S1352231097000174
Title:Forests and forestry: radiation protection measures with special reference to the Chernobyl accident zone
Author: F.A. Tikhomirov, A.I. Shcheglov, V.P. Sidorov
Reference: Science of The Total Environment, Volume 137, Issues 1–3, 2–4 September 1993, Pages 289-305
DOI: http://dx.doi.org/10.1016/0048-9697(93)90395-M
Keywords: Chernobyl; radiation protection; countermeasures; forest management
Abstract: A large proportion of the area contaminated by the Chernobyl accident in the former USSR is forested and has presented unique problems when considering appropriate post-contamination management and clean-up techniques. These problems are related to the forest’s role as both a source and sink for radioactive contamination. Although it has been suggested that resuspension from forested areas may provide a secondary source of contamination to adjacent land, data collected after the Kyshtym and Chernobyl accidents suggest that forest ecosystems may also be effective in limiting the further spread of contamination away from the point of initial deposition and that this effect will increase over time. Such evidence serves to highlight the importance of these ecosystems in influencing the behaviour of radionuclides immediately after their release to the environment. Management practices for forested areas adopted since 1986 are described and a critical appraisal is presented of engineering-based countermeasures implemented over the initial post-accident period. These were intended to remove large quantities of contaminated materials from the forest environment. However, it is suggested that the natural processes of self-decontamination of trees and forest floor litter layers are sufficiently rapid and efficient to necessitate radical alterations to the technologically based approaches adopted in the first 2 years after the Chernobyl accident.
URL: http://www.sciencedirect.com/science/article/pii/004896979390395M
