タグ「137Cs」
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: A three-dimensional model for the dispersion of radioactive substances in marine ecosystems. Application to the Baltic Sea after the Chernobyl disaster
Author: M. Toscano-Jimenez, R. García-Tenorio
Reference: Ocean Engineering, Volume 31, Issues 8–9, June 2004, Pages 999-1018
DOI: http://dx.doi.org/10.1016/j.oceaneng.2003.11.003
Keywords: 3-D model; Diffusion scales; 137Cs; Chernobyl; Baltic Sea
Abstract: A 3-D dispersion model has been developed to simulate the dispersion of nuclear contaminants in marine ecosystems. This model is characterized by presenting high spatial resolution, by taking into account the possible sedimentation of a fraction of the contaminants, and by formulating the diffusion processes using an original approach.
The model has been applied and validated taking the Baltic Sea as its scenario, and using the 137Cs originating from the Chernobyl accident as the substance which experienced the dispersion. The simulation of a year’s dispersion of the 137Cs in the Baltic sea (just after the Chernobyl accident) has been performed.
URL: http://www.sciencedirect.com/science/article/pii/S0029801804000046
Title: Changes in the forms of 137Cs and its availability for plants as dependent on properties of fallout after the Chernobyl nuclear power plant accident
Author: N.I. Sanzharova, S.V. Fesenko, R.M. Alexakhin, V.S. Anisimov, V.K. Kuznetsov, L.G. Chernyayeva
Reference: Science of The Total Environment, Volume 154, Issue 1, 1 September 1994, Pages 9-22
DOI: http://dx.doi.org/10.1016/0048-9697(94)90609-2
Keywords: Chernobyl NPP; Radionuclide; Forms in soil; Availability; Transfer factor; Ecological half line
Abstract: The dynamics of exchangeable and acid soluble 137Cs content in soils, as well as 137Cs transfer factors for natural vegetation were studied for different sites within a 50-km zone around the Chernobyl nuclear power plant after the 1986 accident. Changes in 137Cs forms in soils during the 6 years after the accidental release of radioactive substances and availability of this radionuclide to plants at that time were dependent on the character of radioactive fallout (fuel particles, aerosols of different dispersion) and soil type. Transformation of different 137Cs species in soils with time after the accident was observed (destruction of fuel particles, ageing of 137Cs and changes in the 137Cs sorption strength of the soil solid phase). Behaviour of 137Cs in the ‘near’ and ‘remote’ zones was different. The content of exchangeable 137Cs in soils was found to have decreased after the accident. The average half-life of 137Cs in grass stand in dry meadow in the ‘remote’ zone is 3.5 years, and in the second (slower) period after the accident, this half-life for 137Cs will amount to about 17 years. The 137Cs transfer factors for peaty swamped soils were 3.7–6.6 times as high as for soils of automorphous series.
URL: http://www.sciencedirect.com/science/article/pii/0048969794906092
Title: Calculations of the deposition of 137Cs from nuclear bomb tests and from the Chernobyl accident over the province of Skåne in the southern part of Sweden based on precipitation
Author: Mats Isaksson, Bengt Erlandsson, Maj-Lena Linderson
Reference: Journal of Environmental Radioactivity, Volume 49, Issue 1, May 2000, Pages 97-112
DOI: http://dx.doi.org/10.1016/S0265-931X(99)00101-0
Keywords: Deposition; Precipitation; Radiocalsium; ; Global fallout; Chernobyl fallout
Abstract: The deposition of over the province of Skåne (an area of about 100×100 km2) in the southern part of Sweden has been investigated. The origin of the deposition of is, in about equal parts, from nuclear weapons tests and from the Chernobyl nuclear accident and amounts to about 1–3 kBq/m2. The activity concentrations of and in soil samples from 16 sites distributed in a grid pattern over the investigated area have been measured and the depositions from the nuclear weapons tests and from the Chernobyl accident have been separated. These pre- and post-Chernobyl activities have been compared with depositions calculated from measurements of the activity concentrations of and in precipitation at two places and from measurements of the precipitation from a network of between 113 and 143 precipitation stations. Comparisons with in situ measurements and with aerial survey measurements have also been made. The agreement is good gain and it has been possible to gain a good and detailed knowledge in retrospect of the deposition from measurements of the deposition per mm of precipitation from just a few stations, and of the precipitation from a network of stations.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X99001010
Title: Analysis of radiocaesium in the Lebanese soil one decade after the Chernobyl accident
Author: O. El Samad, K. Zahraman, R. Baydoun, M. Nasreddine
Reference: Journal of Environmental Radioactivity, Volume 92, Issue 2, 2007, Pages 72-79
DOI: http://dx.doi.org/10.1016/j.jenvrad.2006.09.008
Keywords: 137Cs; Activity concentration; Soil; Chernobyl accident; Lebanon
Abstract: Fallout from the Chernobyl reactor accident due to the transport of a radioactive cloud over Lebanon in the beginning of May 1986 was studied 12 years after the accident for determining the level of 137Cs concentration in soil. Gamma spectroscopy measurements were performed by using coaxial high sensitivity HPGe detectors. More than 90 soil samples were collected from points uniformly distributed throughout the land of Lebanon in order to evaluate their radioactivity. The data obtained showed a relatively high 137Cs activity per surface area contamination, up to 6545 Bq m−2 in the top soil layer 0–3 cm. The average activity of 137Cs in the top soil layer 0–3 cm in depth was 59.7 Bq kg−1 dry soil ranging from 15 to 119 Bq kg−1 dry soil. The horizontal variability was found to be about 45% between the sampling sites. The depth distribution of total 137Cs activity in soil showed an exponential decrease. Estimation of the annual effective dose due to external radiation from 137Cs contaminated soil for selected sites gave values ranging from 19.3 to 91.6 μSv y−1.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X06001676
Title: Seasonal 7Be and 137Cs activities in surface air before and after the Chernobyl event
Author: A. Kulan
Reference: Journal of Environmental Radioactivity, Volume 90, Issue 2, 2006, Pages 140-150
DOI: http://dx.doi.org/10.1016/j.jenvrad.2006.06.010
Keywords: 7Be; 137Cs; Atmosphere; Aerosols; Chernobyl fallout; Nuclear weapons fallout; Sweden; Europe
Abstract: Seasonal fluctuations of cosmogenic 7Be (T1/2 = 53.4 days) and anthropogenic 137Cs (T1/2 = 30 years) activities in surface air (aerosols) have been extracted from a long data record (1972–2000) at high latitude (56°N–68°N, Sweden). Normalization to weekly average values was used to control long-term trends so that cyclical trends could be investigated. Enhanced 7Be activity was observed in spring and summer seasons and likely relates to the seasonal thinning of the tropopause. Variations in the 137Cs activity record seem to reflect how the isotope was injected in the atmosphere (stratospheric from bomb tests and tropospheric from the Chernobyl accident) and subsequent transport mechanisms. Accordingly, until 1986, the surface air 137Cs activity was strongly related to nuclear weapons test fallout and exhibits temporal fluctuations resembling the 7Be. Conversely, since 1986 the Chernobyl-produced 137Cs dominates the long-term record that shows annual cycles that are strongly controlled by atmospheric boundary layer conditions. Additionally, short-term data within the post-Chernobyl period suggest subtle intrusion of air masses rich in 137Cs that may occur throughout the year, and differences resulting from spatial occurrence at these latitudes. This is an important observation that may have to do with year-to-year variation and calls for caution when interpreting short-term data records.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X06001032
Title: Remediation strategies for rural territories contaminated by the Chernobyl accident
Author: P. Jacob, S. Fesenko, S.K. Firsakova, I.A. Likhtarev, C. Schotola, R.M. Alexakhin, Y.M. Zhuchenko, L. Kovgan, N.I. Sanzharova, V. Ageyets
Reference: Journal of Environmental Radioactivity, Volume 56, Issues 1–2, 2001, Pages 51-76
DOI: http://dx.doi.org/10.1016/S0265-931X(01)00047-9
Keywords: Chernobyl accident;137Cs; Remediation; Contamination; Dose
Abstract: The objective of the present paper is to derive remediation strategies for rural settlements contaminated by the Chernobyl accident in which annual doses to a critical group still exceed 1 mSv. Extensive radioecological data have been collected for 70 contaminated settlements. A dose model based on these data resulted in estimates that are on average close to and a bit less than the official dose estimates (‘catalogue doses’) published by the responsible Ministries of Belarus, Russia and Ukraine. For eight remedial actions that can be applied on a large scale, effectiveness and costs have been assessed in light of their dependence on soil type, contamination level and on the degree of previous application of remedial actions. Remediation strategies were derived for each of the 70 settlements by choosing remedial actions with lowest costs per averted dose and with highest degree of acceptability among the farmers and local authorities until annual doses are assessed to fall below 1 mSv. The results were generalised to 11 contamination/internal-dose categories. The total numbers of rural inhabitants and privately owned cows in the three countries distributed over the categories were determined and predicted until the year 2015. Based on these data, costs and averted doses were derived for the whole affected population. The main results are (i) about 2000 Sv can be averted at relatively low costs, (ii) the emphasis on reducing external exposures should be increased, (iii) radical improvement of hay-land and meadows and application of Prussian blue to cows should be performed on a large scale if annual doses of 1 mSv are an aim to be achieved, (iv) additional remedial actions of importance are fertilising of potato fields, distribution of food monitors and restriction of mushroom consumption, and (v) for inhabitants of some settlements (in total about 8600) annual doses cannot be reduced below 1 mSv by the remedial actions considered.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X01000479
Title: Chernobyl radioactivity persists in reindeer
Author: Lavrans Skuterud, Eldar Gaare, Inger Margrethe Eikelmann, Knut Hove, Eiliv Steinnes
Reference: Journal of Environmental Radioactivity, Volume 83, Issue 2, 2005, Pages 231-252
DOI: http://dx.doi.org/10.1016/j.jenvrad.2005.04.008
Keywords: Caesium-137; Effective half-life; Reindeer; Lichen; Plant; Food chain; Chernobyl
Abstract: Transfer of 137Cs in the soil–plant/lichen–reindeer food chain was studied in central (Østre Namdal) and southern Norway (Vågå) during 2000–2003. Reindeer from these areas have been continuously subjected to countermeasure application since the 1986 Chernobyl accident. In both areas no decline in 137Cs concentrations was detectable in reindeer slaughtered in autumn since 1995, or in reindeer slaughtered in winter since 1998–1999. Seasonal differences in 137Cs concentrations in reindeer have been less pronounced in recent years, with 137Cs concentrations occasionally higher in autumn than in winter. Soil-to-plant 137Cs transfer was significantly higher in Østre Namdal than in Vågå. Climatic influences on lichen growth and abundance, and on soil properties that influence the availability of 137Cs for plant uptake, are hypothesized to have a larger impact on long-term transfer of radiocaesium in the soil–plant/lichen–reindeer food chain than has been previously observed.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X05001402
Title: Accumulation of Chernobyl-derived 137Cs in bottom sediments of some Finnish lakes
Author: Erkki Ilus, Ritva Saxén
Reference: Journal of Environmental Radioactivity, Volume 82, Issue 2, 2005, Pages 199-221
DOI: http://dx.doi.org/10.1016/j.jenvrad.2005.01.008
Keywords: Lake sediments; Chernobyl fallout; Caesium-137; Sedimentation rate
Abstract: The amount and vertical distribution of Chernobyl-derived 137Cs in the bottom sediments of some Finnish lakes were studied. Sediment and surface water samples were taken in 2000 and 2003 from 12 stations in nine lakes and the results were compared with those obtained in corresponding surveys carried out in 1969, 1978, 1988 and 1990. Each of the five deposition categories of Chernobyl fallout in Finland were represented. The depth profiles of 137Cs in the sediments showed considerable variety in the lakes studied. The peak values varied between 1.5 and 46 kBq kg−1 dry wt. The size and shape of the peak did not always correlate with the amount of deposition in the area, but on the other hand, reflected differences in sedimentation processes in different lakes. In some of the lakes the peak still occurred in the uppermost (0–2 cm) sediment layer, but in an extreme case the peak occurred at a depth of 22–23 cm corresponding to a sedimentation rate of 16 mm year−1 during the 14 years after the Chernobyl accident. The total amounts of 137Cs in sediments varied from 15 to 170 kBq m−2 at the sampling stations studied. Since 1990, the amounts have continued to increase slightly in two lakes, but started to decrease in the other lakes. In most of the lakes, the total amounts of 137Cs in sediments were about 1.5–2 times higher than in local deposition. In two lakes, the ratio was below 1, but in one case 3.2. Compared with the total amounts of 137Cs at the same stations in the late 1960s and 1970s, the values were now at their highest, at about 60-fold. The most important factors affecting 137Cs values in sediments were the local amount of deposition and the type of the lake and the sediment, but in addition, there were a number of other factors to be considered.
URL: http://www.sciencedirect.com/science/article/pii/S0265931X0500041X
