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1.
  • Telldahl, Ylva (author)
  • Skeletal changes in lower limb bones in domestic cattle from Eketorp ringfort on the Öland island in Sweden
  • In: International Journal of Paleopathology. - 1879-9817 .- 1879-9825.
  • Journal article (peer-reviewed)abstract
    • Abstract: In this paper the occurrence of skeletal changes in joints has been investigated in cattleextremities. The bone elements derive from the archaeological site Eketorp ringfort on the Ölandisland in Sweden dated between Iron Age - Middle Age (ca 300 - 1200/50 A.D.). The analysis wasconducted in order to examine skeletal lesions and their connection to traction work. Different skeletallesions were recorded and the joint surface on metapodia and phalanges was divided in 4-7 sites toexamine if different types of lesions were located on particular sites of the articular facets or ifdifferent types of lesions were noted in bone elements from fore- and hindlimbs. The results show thatmetatarsals exhibited a higher frequency of pathologies in both phases compared to metacarpals whileanterior phalanges 1 and 2 had a higher occurrence of lesions than the posterior elements. The studyalso demonstrates that the type and location of depressions on joint surfaces are unevenly distributedbetween bone elements. Furthermore the results show that the occurrence of skeletal lesions weremore common in robust animals.
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2.
  • Abrahamsson, Otto, et al. (author)
  • Presentation and analysis of a model simulating the response of potash treatment of lakes
  • 1997
  • In: Journal of Environmental Radioactivity. - 0265-931X .- 1879-1700. ; 37:3, s. 287-306
  • Journal article (peer-reviewed)abstract
    • The potassium concentration in a lake may influence the caesium levels in lake biota. The biouptake and potential ecosystem effects of a caesium fall-out can be limited by addition of potassium, for example, by a potash treatment. This work presents for the first time a simple and practically useful model to facilitate the planning and to predict the outcome of potash treatments by simulating the processes that regulate the water chemical response of such a treatment. The model is a mixed model in the sense that it contains both statistical regressions and dynamic interactions within a lake ecosystem. This paper focuses on the dynamic processes and gives both calibrations and extensive validations of the model. A few examples on the practical use of the model are presented. The results indicate that the model, using only easily accessible input data, can, in fact, give good predictions on the increase and duration in potassium concentration following a potash treatment.
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3.
  • Isaksson, Mats, 1961, et al. (author)
  • Calculations of the deposition of 137Cs from nuclear bomb tests and from the Chernobyl accident over the province of Skane in the southern part of Sweden based on precipitation
  • 2000
  • In: Journal of Environmental Radioactivity. - 0265-931X .- 1879-1700. ; 49, s. 97-112
  • Journal article (peer-reviewed)abstract
    • The deposition of 137Cs over the province of Skane (an area of about 100x100km2) in the southern part of Sweden has been investigated. The origin of the deposition of 137Cs is, in about equal parts, from nuclear weapons tests and from the Chernobyl nuclear accident and amounts to about 1-3kBq/m2. The activity concentrations of 134Cs and 137Cs 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 134Cs and 137Cs 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. Copyright (C) 2000 Elsevier Science Ltd.
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4.
  • Adliene, Diana, et al. (author)
  • Assessment of the environmental contamination with long-lived radionuclides around an operating RBMK reactor station
  • 2006
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 90:1, s. 68-77
  • Journal article (peer-reviewed)abstract
    • The presence of man-made gamma emitting radionuclides in the region within 32 km radius of the Ignalina NPP/Lithuania has been investigated during the period 2001-2004, prior to the closure of the first 4 the two operating RBMK 1500-type reactors. Gamma spectrometric measurements of various terrestrial and aquatic plants as well as of soil samples showed moderate environmental contamination with the fission product Cs-137 and with the neutron activation products Co-60 and Mn-54. Traces of the activation products Zn-65 and Ag-110m were found in the nearest vicinity of the NPP. Activity concentrations were inhomogeneously distributed in the area of interest. Moss and algae samples showed the highest uptake of radionuclides. In addition to the gamma spectrometric measurements, the levels of C-14 were determined in the same bio-indicator samples using accelerator mass spectrometry. (c) 2006 Elsevier Ltd. All rights reserved.
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5.
  • Akbari, Keramatollah, 1961-, et al. (author)
  • Influence of indoor air conditions on radon concentration in a detached house
  • 2013
  • In: Journal of Environmental Radioactivity. - Elsevier : Elsevier BV. - 0265-931X .- 1879-1700. ; 116, s. 166-173
  • Journal article (peer-reviewed)abstract
    • Radon is released from soil and building materials and can accumulate in residential buildings. Breathing radon and radon progeny for extended periods hazardous to health and can lead to lung cancer. Indoor air conditions and ventilation systems strongly influence indoor radon concentrations. This paper focuses on effects of air change rate, indoor temperature and relative humidity on indoor radon concentrations in a one family detached house in Stockholm, Sweden.In this study a heat recovery ventilation system unit was used to control the ventilation rate and a continuous radon monitor (CRM) was used to measure radon levels. FLUENT, a computational fluid dynamics (CFD) software package was used to simulate radon entry into the building and air change rate, indoor temperature and relative humidity effects using a numerical approach.The results from analytical solution, measurements and numerical simulations showed that air change rate, indoor temperature and moisture had significant effects on indoor radon concentration. Increasing air change rate reduces radon level and for a specific air change rate (in this work Ach = 0.5) there was a range of temperature and relative humidity that minimized radon levels. In this case study minimum radon levels were obtained at temperatures between 20 and 22 °C and a relative humidity of 50-60%
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6.
  • Almgren, Sara, 1979, et al. (author)
  • Long-term investigation of anthropogenic and naturally occurring radionuclides at reference sites in western Sweden.
  • 2009
  • In: Journal of environmental radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 100:7, s. 599-604
  • Journal article (peer-reviewed)abstract
    • In case of an accidental release of radioactive substances into the environment, it is important to quickly and reliably estimate the radiation dose received by people in the affected area, and to determine the extent of the contamination. Measurements of the extent of the release and the subsequent contamination can be facilitated if there are predetermined reference sampling sites with known background radiation and inventory of radionuclides. Since 1996, 34 reference sites for soil sampling, field gamma, and intensimeter measurements have been established in western Sweden. Time series data for dose rates and radioisotope inventory have been collected at these sites, allowing for the investigation of changes in these parameters over time. The mass activity densities for the uranium and thorium series elements varied approximately between 10 and 50 Bq/kg and between 10 and 40 Bq/kg, respectively. The mass activity density of (40)K was approximately in the range 300-800 Bq/kg. The radiation exposure due to (137)Cs was rather small in this area. The dose rates calculated from in situ measurement data showed that the contribution to the total dose rate was almost entirely due to naturally occurring radionuclides. The measured dose rate was about twice as high as the calculated rate, even after subtracting the contribution from cosmic radiation. This may be explained by the fact that intensimeters generally are calibrated to measure the quantity ambient dose equivalent, which should not underestimate the effective dose.
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7.
  • Alonzo, Frederic, et al. (author)
  • Modelling the propagation of effects of chronic exposure to ionising radiation from individuals to populations
  • 2008
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 99:9, s. 1464-1473
  • Journal article (peer-reviewed)abstract
    • This study evaluated the potential effect of ionising radiation on population growth using simple population models and parameter values derived from chronic exposure experiments in two invertebrate species with contrasting life-history strategies. In the earthworm Eisenia fetida, models predicted increasing delay in population growth with increasing gamma dose rate (up to 0.6 generation times at 11 mGy h(-1)). Population extinction was predicted at 43 mGy h(-1). In the microcrustacean Daphnia magna, models predicted increasing delay in population growth with increasing alpha dose rate (up to 0.8 generation times at 15.0 mGy h(-1)), only after two successive generations were exposed. The study examined population effects of changes in different individual endpoints (including survival, number of offspring produced and time to first reproduction). Models showed that the two species did not respond equally to equivalent levels of change, the fast growing daphnids being more susceptible to reduction in fecundity or delay in reproduction than the slow growing earthworms. This suggested that susceptibility of a population to ionising radiation cannot be considered independent of the species' life history.
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8.
  • Alonzo, Frederic, et al. (author)
  • Population modelling to compare chronic external radiotoxicity between individual and population endpoints in four taxonomic groups
  • 2016
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 152, s. 46-59
  • Journal article (peer-reviewed)abstract
    • In this study, we modelled population responses to chronic external gamma radiation in 12 laboratory species (including aquatic and soil invertebrates, fish and terrestrial mammals). Our aim was to compare radiosensitivity between individual and population endpoints and to examine how internationally proposed benchmarks for environmental radioprotection protected species against various risks at the population level. To do so, we used population matrix models, combining life history and chronic radiotoxicity data (derived from laboratory experiments and described in the literature and the FRED ERICA database) to simulate changes in population endpoints (net reproductive rate R-0, asymptotic population growth rate lambda, equilibrium population size N-eq) for a range of dose rates. Elasticity analyses of models showed that population responses differed depending on the affected individual endpoint (juvenile or adult survival, delay in maturity or reduction in fecundity), the considered population endpoint (R-0, lambda or N-eq) and the life history of the studied species. Among population endpoints, net reproductive rate R-0 showed the lowest EDR10 (effective dose rate inducing 10% effect) in all species, with values ranging from 26 mu Gy h(-1) in the mouse Mus musculus to 38,000 mu Gy h(-1) in the fish Oryzias latipes. For several species, EDR10 for population endpoints were lower than the lowest EDR10 for individual endpoints. Various population level risks, differing in severity for the population, were investigated. Population extinction (predicted when radiation effects caused population growth rate lambda to decrease below 1, indicating that no population growth in the long term) was predicted for dose rates ranging from 2700 mu Gy h(-1) in fish to 12,000 mu Gy h(-1) in soil invertebrates. A milder risk, that population growth rate lambda will be reduced by 10% of the reduction causing extinction, was predicted for dose rates ranging from 24 mu Gy h(-1) in mammals to 1800 mu Gy h(-1) in soil invertebrates. These predictions suggested that proposed reference benchmarks from the literature for different taxonomic groups protected all simulated species against population extinction. A generic reference benchmark of 10 mu Gy h(-1) protected all simulated species against 10% of the effect causing population extinction. Finally, a risk of pseudo-extinction was predicted from 2.0 mu Gy h(-1) in mammals to 970 mu Gy h(-1) in soil invertebrates, representing a slight but statistically significant population decline, the importance of which remains to be evaluated in natural settings.
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9.
  • Andersson, Kasper G, et al. (author)
  • Revision of deposition and weathering parameters for the ingestion dose module (ECOSYS) of the ARGOS and RODOS decision support systems.
  • 2011
  • In: Journal of environmental radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X.
  • Journal article (peer-reviewed)abstract
    • The ECOSYS model is the ingestion dose model integrated in the ARGOS and RODOS decision support systems for nuclear emergency management. The parameters used in this model have however not been updated in recent years, where the level of knowledge on various environmental processes has increased considerably. A Nordic work group has carried out a series of evaluations of the general validity of current ECOSYS default parameters. This paper specifically discusses the parameter revisions required with respect to the modelling of deposition and natural weathering of contaminants on agricultural crops, to enable the trustworthy prognostic modelling that is essential to ensure justification and optimisation of countermeasure strategies. New modelling approaches are outlined, since it was found that current ECOSYS approaches for deposition and natural weathering could lead to large prognostic errors.
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10.
  • Beresford, Nicholas A., et al. (author)
  • Making the most of what we have : application of extrapolation approaches in radioecological wildlife transfer models
  • 2016
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 151, s. 373-386
  • Journal article (peer-reviewed)abstract
    • We will never have data to populate all of the potential radioecological modelling parameters required for wildlife assessments. Therefore, we need robust extrapolation approaches which allow us to make best use of our available knowledge. This paper reviews and, in some cases, develops, tests and validates some of the suggested extrapolation approaches. The concentration ratio (CRproduct-diet or CRwo-diet) is shown to be a generic (trans-species) parameter which should enable the more abundant data for farm animals to be applied to wild species. An allometric model for predicting the biological half-life of radionuclides in vertebrates is further tested and generally shown to perform acceptably. However, to fully exploit allometry we need to understand why some elements do not scale to expected values. For aquatic ecosystems, the relationship between log10(a) (a parameter from the allometric relationship for the organism-water concentration ratio) and log(K-d) presents a potential opportunity to estimate concentration ratios using K-d values. An alternative approach to the CRwo-media model proposed for estimating the transfer of radionuclides to freshwater fish is used to satisfactorily predict activity concentrations in fish of different species from three lakes. We recommend that this approach (REML modelling) be further investigated and developed for other radionuclides and across a wider range of organisms and ecosystems. Ecological stoichiometry shows potential as an extrapolation method in radioecology, either from one element to another or from one species to another. Although some of the approaches considered require further development and testing, we demonstrate the potential to significantly improve predictions of radionuclide transfer to wildlife by making better use of available data.
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11.
  • Bernhardsson, Christian, et al. (author)
  • Spatial variability of the dose rate from (137)Cs fallout in settlements in Russia and Belarus more than two decades after the Chernobyl accident.
  • 2015
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 149, s. 144-149
  • Journal article (peer-reviewed)abstract
    • Radionuclides from the 1986 Chernobyl accident were released and dispersed during a limited period of time, but under widely varying weather conditions. As a result, there was a high geographical variation in the deposited radioactive fallout per unit area over Europe, depending on the released composition of fission products and the weather during the 10 days of releases. If the plume from Chernobyl coincided with rain, then the radionuclides were unevenly distributed on the ground. However, large variations in the initial fallout also occurred locally or even on a meter scale. Over the ensuing years the initial deposition may have been altered further by different weathering processes or human activities such as agriculture, gardening, and decontamination measures. Using measurements taken more than two decades after the accident, we report on the inhomogeneous distribution of the ground deposition of the fission product (137)Cs and its influence on the dose rate 1 m above ground, on both large and small scales (10(ths) of km(2) - 1 m(2)), in the Gomel-Bryansk area close to the border between Belarus and Russia. The dose rate from the deposition was observed to vary by one order of magnitude depending on the size of the area considered, whether human processes were applied to the surface or not, and on location specific properties (e.g. radionuclide migration in soil).
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12.
  • Boson, Jonas, 1976-, et al. (author)
  • Evaluation of Monte Carlo-based calibrations of HPGe detectors for in situ gamma-ray spectrometry
  • 2009
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 100:11, s. 935-940
  • Journal article (peer-reviewed)abstract
    • The aim of this work was to evaluate the use of Monte Carlo-based calibrations for in situ gamma-ray spectrometry. We have performed in situ measurements at five different sites in Sweden using HPGe detectors to determine ground deposition activity levels of (137)Cs from the 1986 Chernobyl accident. Monte Carlo-calculated efficiency calibration factors were compared with corresponding values calculated using a more traditional semi-empirical method. In addition, results for the activity ground deposition were also compared with activity densities found in soil samples. In order to facilitate meaningful comparisons between the different types of results, the combined standard uncertainty of in situ measurements was assessed for both calibration methods. Good agreement, both between the two calibration methods, and between in situ measurements and soil samples, was found at all five sites. Uncertainties in in situ measurements for the given measurement conditions, about 20 years after the fallout occurred, were found to be in the range 15-20% (with a coverage factor k=1, i.e. with a confidence interval of about 68%).
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13.
  • Bradshaw, Clare, et al. (author)
  • Using an Ecosystem Approach to complement protection schemes based on organism-level endpoints
  • 2014
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 136, s. 98-104
  • Journal article (peer-reviewed)abstract
    • Radiation protection goals for ecological resources are focussed on ecological structures and functions at population-, community-, and ecosystem-levels. The current approach to radiation safety for non-human biota relies on organism-level endpoints, and as such is not aligned with the stated overarching protection goals of international agencies. Exposure to stressors can trigger non-linear changes in ecosystem structure and function that cannot be predicted from effects on individual organisms. From the ecological sciences, we know that important interactive dynamics related to such emergent properties determine the flows of goods and services in ecological systems that human societies rely upon. A previous Task Group of the IUR (International Union of Radioecology) has presented the rationale for adding an Ecosystem Approach to the suite of tools available to manage radiation safety. In this paper, we summarize the arguments for an Ecosystem Approach and identify next steps and challenges ahead pertaining to developing and implementing a practical Ecosystem Approach to complement organism-level endpoints currently used in radiation safety.
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14.
  • Bréchignac, Francois, et al. (author)
  • Addressing ecological effects of radiation on populations and ecosystems to improve protection of the environment against radiation : Agreed statements from a Consensus Symposium
  • 2016
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 158, s. 21-29
  • Research review (peer-reviewed)abstract
    • This paper reports the output of a consensus symposium organized by the International Union of Radioecology in November 2015. The symposium gathered an academically diverse group of 30 scientists to consider the still debated ecological impact of radiation on populations and ecosystems. Stimulated by the Chernobyl and Fukushima disasters' accidental contamination of the environment, there is increasing interest in developing environmental radiation protection frameworks. Scientific research conducted in a variety of laboratory and field settings has improved our knowledge of the effects of ionizing radiation on the environment. However, the results from such studies sometimes appear contradictory and there is disagreement about the implications for risk assessment. The Symposium discussions therefore focused on issues that might lead to different interpretations of the results, such as laboratory versus field approaches, organism versus population and ecosystemic inference strategies, dose estimation approaches and their significance under chronic exposure conditions. The participating scientists, from across the spectrum of disciplines and research areas, extending also beyond the traditional radioecology community, successfully developed a constructive spirit directed at understanding discrepancies. From the discussions, the group has derived seven consensus statements related to environmental protection against radiation, which are supplemented with some recommendations. Each of these statements is contextualized and discussed in view of contributing to the orientation and integration of future research, the results of which should yield better consensus on the ecological impact of radiation and consolidate suitable approaches for efficient radiological protection of the environment.
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15.
  • Chen, Peng, et al. (author)
  • Use of Be-10 isotope to predict landscape development in the source area of the Yellow River (SAYR), northeastern Qinghai-Tibet Plateau
  • 2019
  • In: Journal of Environmental Radioactivity. - : ELSEVIER SCI LTD. - 0265-931X .- 1879-1700. ; 203, s. 187-199
  • Journal article (peer-reviewed)abstract
    • The magnitude of soil and sediment erosion and accumulation processes can profoundly affect landscape development and hamper efficient management of natural resources. Consequently, estimating the rates and causes of these processes is essential, particularly in remote regions, for prediction of changes in landform and river evolution and protection of local ecosystem. We here present the results of a soil and sediment erosion investigation in the Source Area of the Yellow River (SAYR), northeast Qinghai-Tibet Plateau based on a combined analysis of Be-10 cosmogenic isotope and Soil and Water Assessment Tool (SWAT) simulation modelling. The data reveal variable soil erosion trends that range between 103 and 830 t km(-2) a(-1). The low values occur in the western part of the basin that are associated with low sediment yield, while the high values appear in the dominant sediment export part of the basin along the main stream of the Yellow River in the east. Generally, soil and sediment accumulation is characterized by high Be-10 concentration in the western part and the northwest of Ngoring Lake. The style of landform development by the erosion/accumulation processes is closely linked to the distribution and degradation extent of the permafrost in the study region. Soil surface erosion increases with more permafrost degradation from the western to the eastern part of the basin, and surface soil particles are dominantly removed from the surface rather than deeper layers.
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16.
  • Cwanek, Anna, et al. (author)
  • The study of Canadian Arctic freshwater system toward radioactive contamination - status in 1999
  • 2021
  • In: Journal of Environmental Radioactivity. - : ELSEVIER SCI LTD. - 0265-931X .- 1879-1700. ; 226
  • Journal article (peer-reviewed)abstract
    • This work provides a novel data set on accumulations of both anthropogenic (Cs-137, Pu-238, Pu239+240, Am-241) and natural (Pb-210, Ra-226, Th-232) radionuclides and an element (K). Sampling of soils and lake sediments was accomplished in 1999 during Tundra Northwest (TNW-99) international expedition to a remote region of the Canadian Arctic. The sediment ages and sedimentation rates were determined. The obtained results overall indicated a high geographical diversity of contamination levels and trends. Accumulation rates were also differential, and a sediment focusing contribution was distinctly visible. Radioactive pollution was found to be lower relative to temperate counterparts. The activity ratios of anthropogenic radionuclides corresponded to global fallout as a prevailing source in the entire examined area. The post-Chernobyl radiocaesium was observed for the westernmost lake only. The elevated level of Cs-137 and Pu239+240 in the topmost sediment at the northern and eastern Arctic Archipelago was attributed to recent resuspension and subsequent redistribution of radionuclides.
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17.
  • De La Torre Luque, Pedro, et al. (author)
  • Testing machine learning algorithms for the prediction of depositional fluxes of the radionuclides 7Be, 210Pb and 40K
  • 2023
  • In: Journal of Environmental Radioactivity. - 0265-931X .- 1879-1700. ; 265
  • Journal article (peer-reviewed)abstract
    • The monthly depositional fluxes of 7Be, 210Pb and 40K were measured at Malaga, (Southern Spain) from 2005 to 2018. In this work, the depositional fluxes of these radionuclides are investigated and their relations with several atmospheric variables have been studied by applying two popular machine learning methods: Random Forest and Neural Network algorithms. We extensively test different configurations of these algorithms and demonstrate their predictive ability for reproducing depositional fluxes. The models derived with Neural Networks achieve slightly better results, in average, although similar, having into account the uncertainties. The mean Pearson-R coefficients, evaluated with a k-fold cross-validation method, are around 0.85 for the three radionuclides using Neural Network models, while they go down to 0.83, 0.79 and 0.8 for 7Be, 210Pb and 40K, respectively, for the Random Forest models. Additionally, applying the Recursive Feature Elimination technique we determine the variables more correlated with the depositional fluxes of these radionuclides, which elucidates the main dependences of their temporal variability.
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18.
  • Dias, C M, et al. (author)
  • 14CO2 dispersion around two PWR nuclear power plants in Brazil.
  • 2009
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 100:7, s. 574-580
  • Journal article (peer-reviewed)abstract
    • Atmospheric air samples were taken within 3 km from power plants encompassing five different distances and wind directions. Samples were taken between 2002 and 2005 aiming to evaluate the environmental C-14 enrichment due to the operation of Brazilian nuclear power plants. The sampling system consisted of a pump connected to a trapping column filled with a 3 M NaOH solution. The trapped C-14 by using a single stage accelerator mass spectrometry (SSAMS). CO2 was analyzed for All sampling sites revealed measurable C-14 excess values. The maximum excesses were of 15 and 14 mBq/m(3) for sampling sites placed at NE of the power plants, which is the main wind direction in the area. The mean excesses values were 12 mBq/m(3) to the NE direction, 8 mBq/m to the E, 10 mBq/m to the N, 8 mBq/m(3) to the WNW and 7 mBq/m(3) to the W direction (increasing distances from NE to W). Compared to other Light Water Reactors (LWR) data, these means' values are significantly higher than the average worldwide reported value of 3 mBq/m(3). Available data indicate that the observed values are not related to C-14 emission by the power plants vent stack. Other factors, such as topography, seem to have an important role because it affects wind dispersion thus favoring C-14 accumulation in the sampled area. Moreover, the high elevations around the power plants enhance the chances to measure high values of C-14 since the plume can be intercepted before it is drawn to the ground. Modeling of the plume has shown that its dispersion does not follow a Gaussian model and that agreement between atmospheric CO2 and vegetation C-14 activities occurs only for sampling sites placed at NE of the power plants. (c) 2009 Elsevier Ltd. All rights reserved.
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19.
  • Dias, Cintia Melazo, et al. (author)
  • C-14, delta C-13 and total C content in soils around a Brazilian PWR nuclear power plant
  • 2009
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 100:4, s. 348-353
  • Journal article (peer-reviewed)abstract
    • Nuclear power plants release C-14 during routine operation mainly as airborne gaseous effluents. Because of the long half-life (5730 years) and biological importance of this radionuclide (it is incorporated in plant tissue by photosynthesis), several countries have monitoring programs in order to quantify and control these emissions. This paper compares the activity of C-14 in soils taken within I km from a Brazilian nuclear power plant with soils taken within a reference area located 50 km away from the reactor site. Analyses of total carbon, delta C-13 and Cs-137 were also performed in order to understand the local soil dynamics. Except for one of the profiles, the isotopic composition of soil organic carbon reflected the actual forest vegetation present in both areas. The Cs-137 data show that the soils from the base of hills are probably allocthonous. The C-14 Measurements showed that there is no accumulation due to the operation of the nuclear facility, although excess C-14 Was found in the litter taken in the area close to power plant. This indicates that the anthropogenic signal observed in the litter fall has not been transferred yet to the soil. This study is part of an extensive research programme in which other samples including air, vegetation and gaseous effluents (taken in the vent stack of the Brazilian nuclear power reactors Angra I and II) were also analyzed. The present paper aimed to evaluate how C-14 emissions from the nuclear power plant are transferred and stored by soils present in the Surroundings of the reactor site. This is the first study concerning anthropogenic 14C in soils in Brazil. (9) 2009 Elsevier Ltd. All rights reserved.
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20.
  • Döse, Magnus, et al. (author)
  • Naturally occurring radioactivity in some Swedish concretes and their constituents - Assessment by using I-index and dose-model
  • 2016
  • In: Journal of Environmental Radioactivity. - : Elsevier. - 0265-931X .- 1879-1700. ; 155-156, s. 105-111
  • Journal article (peer-reviewed)abstract
    • The reference level for effective dose due to gamma radiation from building materials and construction products used for dwellings is set to 1 mSv per year (EC, 1996, 1999), (CE, 2014). Given the specific conditions presented by the EC in report 112 (1999) considering building and construction materials, an I-index of 1 may generate an effective dose of 1 mSv per year. This paper presents a comparison of the activity concentrations of 4 0K, 226Ra and 232Th of aggregates and when these aggregates constitute a part of concrete. The activity concentration assessment tool for building and construction materials, the I-index, introduced by the EC in 1996, is used in the comparison. A comparison of the I-indices values are also made with a recently presented dose model by Hoffman (2014), where density variations of the construction material and thickness of the construction walls within the building are considered. There was a ~16-19% lower activity index in concretes than in the corresponding aggregates. The model by Hoffman further implies that the differences between the I-indices of aggregates and the concretes' final effective doses are even larger. The difference is due, mainly to a dilution effect of the added cement with low levels of natural radioisotopes, but also to a different and slightly higher subtracted background value (terrestrial value) used in the modeled calculation of the revised I-index by Hoffman (2014). Only very minimal contributions to the annual dose could be related to the water and additives used, due to their very low content of radionuclides reported.
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21.
  • Englund, Edvard, et al. (author)
  • Tracing anthropogenic nuclear activity with I-129 in lake sediment
  • 2008
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 99:2, s. 219-229
  • Journal article (peer-reviewed)abstract
    • This study reports the first data of I-129 fallout in Scandinavia, covering the last 80 years. The investigation is based on sediment sections from a lake in central Sweden. In addition to analysis of I-129, a combination of several radionuclides (Pb-210, Cs-137 and C-14) was used to establish an accurate chronology of the sediment profile. The concentration of I-129 exhibits an increasing trend (similar to 10(7) to similar to 10(9) atoms/g) during the last 40 years, suggesting a significant atmospheric input from the nuclear reprocessing facilities in Sellafield (UK) and La Hague (France). A peak corresponding to fallout from the Chernobyl accident (1986) is clearly distinguishable, whereas the impact of fallout from the nuclear weapons' tests since the early 1950s is not distinguished.
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22.
  • Eriksson, M, et al. (author)
  • Distribution and flux of Pu-238, Pu-239,Pu-240, Am-241, Cs-137 and Pb-210 to high arctic lakes in the Thule district (Greenland)
  • 2004
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 75:3, s. 285-299
  • Journal article (peer-reviewed)abstract
    • Environmental samples (soil, sediment and lake water) in the Thule area (NW Greenland) have been studied to assess the contamination of radionuclides originating from a nuclear weapons accident (the Thule accident in 1968). Four lakes were chosen at different distances from the point of impact with the Thule air base community situated in between. The sedimentation rates in the lakes varied from 0.4 mm a(-1) (5 a a(-1) to 1.6 mm a(-1) (82 mg cm(-2) a(-1)). With these sedimentation rates, it is not possible to resolve the Pu-239,Pu-240 global fallout peak from a possible Pu-239,Pu-240 "accident" peak in the sediment depth profiles. However, the Pu-239,Pu-240/Cs-137 and the Pu-238/Pu-239,Pu-240 ratios agreed well with global fallout ratios, indicating that plutonium originating from the accident had not reached these lakes. This also indicates that the Thule air base community has probably only been exposed to radionuclides from the accident to a very limited extent. A limited study showed that Pb-210 could not be used as a normalizing nuclide to explain the transport of transuranic elements from the catchment area to the lake, i.e. Pb-210 has a different transport mechanism from that of the transuranic elements studied in this investigation.
  •  
23.
  • Eriksson, Mats, et al. (author)
  • On the use of MnO2 cartridges for the plutonium determination in seawater
  • 2019
  • In: Journal of Environmental Radioactivity. - : ELSEVIER SCI LTD. - 0265-931X .- 1879-1700. ; 204, s. 66-75
  • Journal article (peer-reviewed)abstract
    • To analyze plutonium (Pu) in open ocean waters can be challenging due to the low seawater concentrations. In this study we compared two techniques for Pu determination, one in-situ MnO2 cartridge system and the more commonly used MnO2 precipitation technique. During the pre-pilot GEOTRACES cruise ANT XXX-1 (2005) we tested MnO2 cartridges for the pre-concentration of Pu from seawater at 19 sampling stations on a transect in the southeastern Atlantic Ocean between Vigo (Spain) and Cape Town (South Africa). Our in-situ sampling setup consisted of one particle cartridge followed by three MnO2 cartridges in a series. Through the system we pumped between 956 and 2700 I of surface seawater with a flow rate between 1.6 and 5.21/min. We found that the adsorption efficiency of a single MnO2 cartridge to adsorb Pu was rather constant and on average a 58 +/- 7%. The adsorption efficiency was also found to be independent of seawater: temperature in the range of 18.3-29.2 degrees C, salinity range 34.2-37.1 parts per thousand, and conductivity in the range of 46.8-58.4 mS/cm. In parallel with the in-situ sampling, discrete surface water samples between 259 and 281 I were taken and Pu was pre-concentrated using the MnO2 precipitation method. We find a good agreement between the Pu concentrations determined with the two different techniques. The in-situ pre-concentration technique requires more radiochemical work in the laboratory but has the advantage that large seawater volumes can be sampled without the necessity for radiochemical processing on-board the ship. The much larger volumes sampled with the in-situ technique compared with the precipitation technique, enables accurate determination of Pu-isotopic ratios with a low relative standard deviation. We have shown in this study that in-situ MnO2 cartridge technique can be used in a reliable way for the determination of dissolved Pu seawater concentration in open ocean waters.
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24.
  • Erlandsson, Bengt, et al. (author)
  • Urban dose rates at Gävle, Göteborg and Lund.
  • 2006
  • In: Journal of environmental radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 85:2-3, s. 241-6
  • Journal article (peer-reviewed)abstract
    • Besides gamma rays from 137Cs emanating from the Chernobyl accident, gamma rays from natural radionuclides are a dominant source of radiation exposure to the public. Since people spend much more time indoors than outdoors the radiation dose obtained inside dwellings contributes greatly to individual and collective doses. Dose rate measurements were made at 20 locations within the city of Göteborg and at further 22 reference sites within a radius of 100 km. Measurements were also made at Gävle and Lund. The dose rates were measured with RNI intensimeters, TLD (LiF) meters and in in situ measurements using an HPGe. The ground cover was grass, asphalt, concrete slates or paving-stones. The dose rates varied between 0.05 and 0.25 microSv/h. Also performed in different ways, measurements made inside and outside buildings at both Göteborg and Gävle showed inside dose rates higher than outside dose rates.
  •  
25.
  • Garcia-Tenorio, Rafael, et al. (author)
  • Journal of Environmental Radioactivity special issue: II International Conference on Radioecological Concentration Processes. (50 years later).
  • 2018
  • In: Journal of environmental radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 186, s. 1-2
  • Journal article (other academic/artistic)abstract
    • An international conference on Radioecological Concentration Processes was held in Seville, Spain, 6-9 November 2016 at the Centro Nacional de Aceleradores. It was attended by 160 participants from 35 different countries. This was the 2nd conference on this item since 1966, 50 years ago. The conference covered aspects of radiological important radionuclides on terrestrial, marine and freshwater environments and has allowed obtaining a clear picture of the status of the Radioecology as a consolidated discipline in the 21st century.
  •  
26.
  • Garnier-Laplace, J., et al. (author)
  • Issues and practices in the use of effects data from FREDERICA in the ERICA Integrated Approach
  • 2008
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 99:9, s. 1474-1483
  • Journal article (peer-reviewed)abstract
    • The ERICA Integrated Approach requires that a risk assessment screening dose rate is defined for the risk characterisation within Tiers 1 and 2. At Tier 3, no numerical screening dose rate is used, and the risk characterisation is driven by methods that can evaluate the possible effects of ionising radiation on reproduction, mortality and morbidity. Species sensitivity distribution has been used to derive the ERICA risk assessment predicted no-effect dose rate (PNEDR). The method used was based on the mathematical processing of data from FRED (FASSET radiation effects database merged with the EPIC database to form FREDERICA) and resulted in a PNEDR of 10 mu Gy/h. This rate was assumed to ascribe sufficient protection of all ecosystems from detrimental effects on structure and function under chronic exposure. The value was weighed against a number of points of comparison: (i) PNEDR values obtained by application of the safety factor method, (ii) background levels, (iii) dose rates triggering effects on radioactively contaminated sites and (iv) former guidelines from literature reviews. In Tier 3, the effects analysis must be driven by the problem formulation and is thus highly case specific. Instead of specific recommendations on numeric values, guidance on the sorts of methods that may be applied for refined effect analysis is Provided and illustrated.
  •  
27.
  • Gjelsvik, Runhild, et al. (author)
  • Polonium-210 and Caesium-137 in lynx (Lynx lynx), wolverine (Gulo gulo) and wolves (Canis lupus).
  • 2014
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 138:May 5, s. 402-409
  • Journal article (peer-reviewed)abstract
    • Wolves, lynx and wolverines are on the top of the food-chain in northern Scandinavia and Finland. (210)Po and (137)Cs have been analysed in samples of liver, kidney and muscle from 28 wolves from Sweden. In addition blood samples were taken from 27 wolves. In 9 of the wolves, samples of muscle, liver and blood were analysed for (210)Po. Samples of liver and muscle were collected from 16 lynx and 16 wolverines from Norway. The liver samples were analysed for (210)Po and (137)Cs. Only (137)Cs analyses were carried out for the muscle samples. The wolves were collected during the winter 2010 and 2011, while the samples for lynx and wolverines were all from 2011. The activity concentrations of (210)Po in wolves were higher for liver (range 20-523 Bq kg(-1) d.w.) and kidney (range 24-942 Bq kg(-1) d.w.) than muscle (range 1-43 Bq kg(-1) d.w.) and blood (range 2-54 Bq kg(-1) d.w.). Activity ratios, (210)Po/(210)Pb, in wolf samples of muscle, liver and blood were in the ranges 2-77, 9-56 and 2-54. Using a wet weight ratio of 3.8 the maximal absorbed dose from (210)Po to wolf liver was estimated to 3500 μGy per year. Compared to wolf, the ranges of (210)Po in liver samples were lower in lynx (range 22-211 Bq kg(-1) d.w.) and wolverine (range16-160 Bq kg(-1) d.w.). Concentration of (137)Cs in wolf samples of muscle, liver, kidney and blood were in the ranges 70-8410 Bq kg(-1) d.w., 36-4050 Bq kg(-1) d.w., 31-3453 Bq kg(-1) d.w. and 4-959 Bq kg(-1) d.w., respectively. (137)Cs in lynx muscle and liver samples were in the ranges 44-13393 Bq kg(-1) d.w. and 125-10260 Bq kg(-1) d.w. The corresponding values for (137)Cs in wolverine were 22-3405 Bq kg(-1) d.w. for liver and 53-4780 Bq kg(-1) d.w. for muscle. The maximal absorbed dose from (137)Cs to lynx was estimated to 3000 μGy per year.
  •  
28.
  • Gommers, A, et al. (author)
  • Radiocaesium soil-to-wood transfer in commercial willow short rotation coppice on contaminated farm land
  • 2005
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 78:3, s. 267-287
  • Journal article (peer-reviewed)abstract
    • The feasibility of willow short rotation coppice (SRC) for energy production as a revaluation tool for severely radiocaesium-contaminated land was studied. The effects of crop age, clone and soil type on the radiocaesium. levels in the wood were assessed following sampling in 14 existing willow SRC fields, planted on radiocaesium-contaminated land in Sweden following Chernobyl deposition. There was only one plot where willow stands of different maturity (R6S2 and R5S4: R, root age and S. shoot age) and clone (Rapp and L78183 both of age category R5S4) were sampled and no significant differences were found. The soils differed among others in clay fraction (3-34%). radiocaesium interception potential (515-6884 meq kg(-1)). soil solution K (0.09-0.95 mM), exchangeable K (0.58-5-77 meq kg(-1)) and cation exchange capacity (31-250 meq kg(-1)). The soil-to-wood transfer factor (TF) of radiocaesium differed significantly between soil types. The TF recorded was generally small (0.00086-0.016 kg kg(-1)), except for willows established on sandy soil (0.19-0.46 kg kg(-1)). Apart from the weak yet significant exponential correlation between the Cs-TF and the solid/liquid distribution coefficient (R-2 = 0.54) or the radiocaesium interception potential. RIP (R-2 = 0.66), no single significant correlations between soil characteristics and TF were, found. The wood-soil solution Cs-137 concentration factor (CF) was significantly related to the potassium concentration in the soil solution. A different relation was, however, found between the sandy Trodje soils (CF = 1078.8 X m(K)(-1.83), R-2 = 0.99) and the other soils (CF = 35.75 X m(K) (-0.61), R-2 =0.61). Differences in the ageing rate of radiocaesium in the soil (hypothesised fraction of bioavailable caesium subjected to fast ageing for Trodje soils only 1 % compared to other soils), exchangeable soil K (0.8-1.8 meq kg(-1) for Trodje soils and 1.5-5.8 meq kg(-1) for the other soils) and the ammonium concentration in the soil solution (0.09-0.31 mM NH4+ for the Trodje soils compared to 0.003-0.11 mM NH4+ for the other soils) are put forward as potential factors explaining the higher CF and TF observed for the Trodje soils. Though from the dataset available it was not possible to unequivocally predict the soil-to-wood- transfer, the generally low TFs observed point to the particular suitability for establishment of SRC on radiocaesium-contaminated land.
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29.
  • Hansen, Violeta, et al. (author)
  • Partition of iodine ((129)I and (127)I) isotopes in soils and marine sediments
  • 2011
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 102:12, s. 1096-1104
  • Journal article (peer-reviewed)abstract
    • Natural organic matter, such as humic and fulvic acids and humin, plays a key role in determining the fate and mobility of radioiodine in soil and sediments. The radioisotope (129)I is continuously produced and released from nuclear fuel reprocessing plants, and as a biophilic element, its environmental mobility is strongly linked to organic matter. Due to its long half-life (15.7 million years), (129)I builds up in the environment and can be traced since the beginning of the nuclear era in reservoirs such as soils and marine sediments. Nevertheless, partition of the isotope between the different types of organic matter in soil and sediment is rarely explored. Here we present a sequential extraction of (129)I and (127)I chemical forms encountered in a Danish soil, a soil reference material (IAEA-375), an anoxic marine sediment from Southern Norway and an oxic sediment from the Barents Sea. The different forms of iodine are related to water soluble, exchangeable, carbonates, oxides as well as iodine bound to humic acid, fulvic acid and to humin and minerals. This is the first study to identify (129)I in humic and fulvic acid and humin. The results show that 30-56% of the total (127)I and 42-60% of the total (129)I are associated with organic matter in soil and sediment samples. At a soil/sediment pH below 5.0-5.5, (127)I and (129)I in the organic fraction associate primarily with the humic acid while at soil/sediment pH > 6 (129)I was mostly found to be bound to fulvic acid. Anoxic conditions seem to increase the mobility and availability of iodine compared to oxic, while subaerial conditions (soils) reduces the availability of water soluble fraction compared to subaqueous (marine) conditions.
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30.
  • Henricsson, Fredrik, et al. (author)
  • Aspects on the analysis of (210)Po.
  • 2011
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 102:5, s. 415-419
  • Journal article (peer-reviewed)abstract
    • There has been little development regarding analysis of polonium (Po) in environmental samples since the 1960ies. This is due to the straightforward spontaneous deposition of this element on silver (Ag), nickel (Ni) or copper (Cu) without any radiochemical separation. For many years, no radiochemical yield determinant was used and it was generally supposed that the yield was 100% after two depositions. Counting was often done using ZnS scintillation counter coupled to a photomultiplier tube. However, the use of the yield determinants (208)Po and (209)Po and the development of alpha spectrometry showed that the yield was lower. Furthermore, the tendency of Po to volatilize at low temperatures constrains the sample preparation techniques; dry-ashing cannot be used. But during the wet-ashing procedure, there are still some losses. The aim of this study was to evaluate the Po losses during wet-ashing by the use of a double-tracer technique. We have found that the losses were about 30% when open glass beakers were used and about 17% when the samples were digested in microwave oven. When long-necked bottles (Kjeldahl flasks) were used, a loss of about 20% was registered. It has also been observed that (210)Pb to some extent is plating out together with its daughter nuclide Po during the electrochemical deposition. This will result in a systematic error since an unknown amount of supported (210)Po will be produced from the (210)Pb decay depending on the fraction of (210)Pb being deposited on the disc and the waiting time between deposition and measurement of the sample. A further consequence of this is that in the assessment of the (210)Pb content in the sample, very often the remaining liquid is stored after deposition for build-up of (210)Po. Since some (210)Pb is lost on the disc, the result for (210)Pb will be too low. Both these systematic errors give rise to a too high (210)Po/(210)Pb ratio. The fraction of (210)Pb which is plating out has been assessed in this study for different matrices and is about 50-90%. During the measurement by solid state Si-detectors, some Po is evaporated in the vacuum conditions contaminating the detectors. Experiments have here been done by heating the discs after deposition which indicate that less Po is evaporated from Ag than from Ni. The losses from Ag are less than that from the other metals probably due to a deeper penetration into the surface of Po. We conclude that in most aspects, Ag is better to use than the other plating metals.
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31.
  • Hevrøy, Tanya H., et al. (author)
  • Radiation effects and ecological processes in a freshwater microcosm
  • 2019
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 203, s. 71-83
  • Journal article (peer-reviewed)abstract
    • Ecosystem response to gamma radiation exposure depends on the different species sensitivities and the multitude of direct and indirect pathways by which individual organisms can be affected, including the potential for complex interactions across multiple trophic levels. In this study, multi-species microcosms were used to in- vestigate effects of ionizing radiation in a model freshwater ecosystem, including endpoints at both structural and functional levels and ecological interactions. Microcosms were exposed for 22 days to a gradient of gamma radiation with four dose rates from 0.72 to 19mGyh−1, which are within the range of those seen at con- taminated sites. Results showed significant dose related effects on photosynthetic parameters for all macrophyte species. No significant effects of radiation were observed for the consumers in the microcosms, however trends indicate the potential for longer-term effects. We also witnessed a different response of Daphnia magna andLemna minor compared to previous single-species studies, illustrating the importance of multispecies studies, which aim to encompass systems more realistic to natural ecosystems. Microcosms allowed us to isolate specific relationships between interacting species in an ecosystem and test the effects, both direct and indirect, of ra- diation on them. In addition, the ecological pathways and processes, and the experimental design itself, was central to understanding the results we witnessed. This type of study is important for radioecology research that has been very much limited to high dose rates and single species studies. This approach to radioecology has been strongly promoted in recent decades and, to our knowledge, this is the first microcosm study performed at dose rates similar to those at contaminated field sites.
  •  
32.
  • Hinton, T. G., et al. (author)
  • An invitation to contribute to a strategic research agenda in radioecology
  • 2013
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 115, s. 73-82
  • Journal article (peer-reviewed)abstract
    • With intentions of integrating a portion of their respective research efforts into a trans-national programme that will enhance radioecology, eight European organisations recently formed the European Radioecology ALLIANCE (www.er-alliance.org). The ALLIANCE is an Association open to other organisations throughout the world with similar interests in promoting radioecology. The ALLIANCE members recognised that their shared radioecological research could be enhanced by efficiently pooling resources among its partner organizations and prioritising group efforts along common themes of mutual interest. A major step in this prioritisation process was to develop a Strategic Research Agenda (SRA). An EC-funded Network of Excellence in Radioecology, called STAR (Strategy for Allied Radioecology), was formed, in part, to develop the SRA. This document is the first published draft of the SRA. The SRA outlines a suggested prioritisation of research topics in radioecology, with the goal of improving research efficiency and more rapidly advancing the science. It responds to the question: What topics, if critically addressed over the next 20 years, would significantly advance radioecology? The three Scientific Challenges presented within the SRA, with their 15 associated research lines, are a strategic vision of what radioecology can achieve in the future. Meeting these challenges will require a directed effort and collaboration with many organisations the world over. Addressing these challenges is important to the advancement of radioecology and in providing scientific knowledge to decision makers. Although the development of the draft SRA has largely been a European effort, the hope is that it will initiate an open dialogue within the international radioecology community and its stakeholders. This is an abbreviated document with the intention of introducing the SRA and inviting contributions from interested stakeholders. Critique and input for improving the SRA are welcomed via a link on the STAR website (www.star-radioecology.org).
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33.
  •  
34.
  • Hofman, D., et al. (author)
  • Computerised Decision Support Systems for the management of freshwater radioecological emergencies : assessment of the state-of-the-art with respect to the experiences and needs of end-users
  • 2011
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 102:2, s. 119-127
  • Journal article (peer-reviewed)abstract
    • Assessment of the environmental and radiological consequences of a nuclear accident requires the management of a great deal of data and information as well as the use of predictive models. Computerised Decision Support Systems (CDSS) are essential tools for this kind of complex assessment and for assisting experts with a rational decision process. The present work focuses on the assessment of the main features of selected state-of-the-art CDSS for off-site management of freshwater ecosystems contaminated by radionuclides. This study involved both developers and end-users of the assessed CDSS and was based on practical customisation exercises, installation and application of the decision systems. Potential end-users can benefit from the availability of several ready-to-use CDSS that allow one to run different kinds of models aimed at predicting the behaviour of radionuclides in aquatic ecosystems, evaluating doses to humans, assessing the effectiveness of different kinds of environmental management interventions and ranking these interventions, accounting for their social, economic and environmental impacts. As a result of the present assessment, the importance of CDSS "integration" became apparent: in many circumstances, different CDSS can be used as complementary tools for the decision-making process. The results of this assessment can also be useful for the future development and improvement of the CDSS.
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35.
  • Holmerin, Isak, et al. (author)
  • Benthic food web structures as an explanation for prolonged ecological half-life of Cs-137 in flatfish species in the Fukushima coastal area
  • 2022
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 246
  • Journal article (peer-reviewed)abstract
    • After the accident at the Fukushima Daiichi Nuclear Power Plant (FDNPP), Japan, in March 2011, Cs-137 in demersal fish had, between 2011 and 2015, a prolonged ecological half-life when compared to pelagic fish. Using stable isotope mixing models combined with gut content analysis and Cs-137 activity concentrations, this study investigated the hypothesis that an unexplored food web structure could be a contributing factor explaining the ecological half-life of Cs-137 in benthic flatfish. Benthic invertebrates and demersal fish species sampled in 2015 still showed Cs-137 activity concentrations higher than pre-accident. The mixing models of stable N and C isotopes and gut content analysis identified deposit, suspension and filter feeders to be the main flatfish food items in the benthos. There was a significant correlation between Cs-137 activity concentrations in specific flatfish species and benthos, and between Cs-137 activity concentrations in benthos and surface sediment. The results of this study partially explained the Cs-137 activity concentrations found in the analysed demersal fish, suggesting that the benthos can be a continuous source of Cs-137 for the demersal fish during this period of time. Extending monitoring programmes to include invertebrates that are not food species for humans would greatly improve our ability to understand the role of trophic transfer pathways and take appropriate management actions.
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36.
  • Holstein, Hanna, et al. (author)
  • Human metabolism of orally administered radioactive cobalt chloride.
  • 2015
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 143, s. 152-158
  • Journal article (peer-reviewed)abstract
    • This study investigated the human gastrointestinal uptake (f1) and subsequent whole-body retention of orally administered inorganic radioactive cobalt. Of eight adult volunteers aged between 24 and 68 years, seven were given solutions of (57)Co (T1/2 = 272 d) containing a stable cobalt carrier, and six were given carrier-free (58)Co (T1/2 = 71 d). The administered activities ranged between 25 and 103 kBq. The observed mean f1, based on 6 days accumulated urinary excretion sampling and whole-body counting, was 0.028 ± 0.0048 for carrier-free (58)Co, and 0.016 ± 0.0021 for carrier-associated (57)Co. These values were in reasonable agreement with values reported from previous studies involving a single intake of inorganic cobalt. The time pattern of the total retention (including residual cobalt in the GI tract) included a short-term component with a biological half-time of 0.71 ± 0.03 d (average ± 1 standard error of the mean for the two nuclides), an intermediate component with a mean half-time of 32 ± 8.5 d, and a long-term component (observed in two volunteers) with half-times ranging from 80 to 720 d for the two isotopes. From the present data we conclude that for the short-lived (57)Co and (58)Co, more than 95% of the internal absorbed dose was delivered within 7 days following oral intake, with a high individual variation influenced by the transit time of the unabsorbed cobalt through the gastro-intestinal tract.
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37.
  • Insulander Björk, Klara, 1982, et al. (author)
  • Experimental determination of concentration factors of Mn, Zn and I in the phytoplankton species Phaeodactylum Tricornutum
  • 2023
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 261
  • Journal article (peer-reviewed)abstract
    • Anthropogenic radionuclides released into the environment cause a radiation dose to wildlife and humans which must be quantified, both to assess the effect of normal releases, and to predict the consequences of a larger, unplanned release. To estimate the spread of the radioactive elements, the ecosystem around release points is modelled, and element uptake is usually quantified by concentration factors (CF), which relates the concentration of an element in an organism to the concentration of the same element in a medium under equilibrium conditions. In this work, we experimentally determine some phytoplankton CF that are needed for improved modelling of the marine ecosystems around nuclear facilities and release points. CFs that require better determination have been identified through literature search. Sensitivity studies, using the currently used ecosystem modelling software PREDO, show that for most studied groups, the dose committed by the respective radionuclides is almost proportional to the corresponding phytoplankton CFs. In the present work, CFs are determined through laboratory experiments with cultured phytoplankton and radionuclides of the concerned elements, assessing the element uptake by the phytoplankton through detection of the emitted radiation. The three CF assessed in this work were those for manganese, zinc and iodine in phytoplankton. Conservative estimates of these CF based on the present data are 40 000 L/kg for manganese, 50 000 L/kg for zinc and 180 L/kg for iodine with the phytoplankton masses referring to their dry weight.
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38.
  •  
39.
  • Jaeschke, Benedict C., et al. (author)
  • Bioaccumulation of tritiated water in phytoplankton and trophic transfer of organically bound tritium to the blue mussel, Mytilus edulis
  • 2013
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 115, s. 28-33
  • Journal article (peer-reviewed)abstract
    • Large releases of tritium are currently permitted in coastal areas due to assumptions that it rapidly disperses in the water and has a low toxicity due to its low energy emissions. This paper presents a laboratory experiment developed to identify previously untested scenarios where tritium may concentrate or transfer in biota relevant to Baltic coastal communities. Phytoplankton populations of Dunaliella tertiolecta and Nodularia spumigena were exposed at different growth-stages, to tritiated water (HTO; 10 MBq l(-1)). Tritiated D. tertiolecta was then fed to mussels, Mytilus edulis, regularly over a period of three weeks. Activity concentrations of phytoplankton and various tissues from the mussel were determined. Both phytoplankton species transformed HTO into organically-bound tritium (OBT) in their tissues. D. tertiolecta accumulated significantly more tritium when allowed to grow exponentially in HTO than if it had already reached the stationary growth phase; both treatments accumulated significantly more than the corresponding treatments of N. spumigena. No effect of growth phase on bioaccumulation of tritium was detectable in N. spumigena following exposure. After mussels were given 3 feeds of tritiated D. tertiolecta, significant levels of tritium were detected in the tissues. Incorporation into most mussel tissues appeared to follow a linear relationship with number of tritiated phytoplankton feeds with no equilibrium, highlighting the potential for biomagnification. Different rates of incorporation in species from a similar functional group highlight the difficulties in using a 'representative' species for modelling the transfer and impact of tritium. Accumulations of organic tritium into the mussel tissues from tritiated-phytoplankton demonstrate an environmentally relevant transfer pathway of tritium even when water-concentrations are reduced, adding weight to the assertion that organically bound tritium acts as a persistent organic pollutant. The persistence, potential for biomagnification and the increased toxicity of organic tritium increases the potential impact on the environment following a release of HTO; current legislation does not adequately take into account the nature of organic forms of tritium and therefore may be underestimating accumulation and toxic effect of tritium in the environment. Such information is necessary to accurately assess the distribution of tritium following routine releases, and to adequately protect the environment and humans.
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40.
  • Jonsson, Lage, 1949-, et al. (author)
  • Various consequences regarding hypothetical dispersion of airborne radioactivity in a city center
  • 2013
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 116, s. 99-113
  • Journal article (peer-reviewed)abstract
    • In case of dispersion of airborne radioactive material in a city center a number of questions will prompt for an answer. While many questions can get their answers in due course of time based on results of tests and sampling, a good understanding of the quantitative effect of dispersion will be very helpful to rescue staff, in particular in the early stage. In the following dose and dose rate estimates are presented for three scenarios including dispersion of radioactivity in a city center. In one case the activity is released in an open place, in another from a roof and in the third case from a source on a street where the wind is blowing along the street. In each case, at specific positions, estimates are made of dose from inhalation, and dose rates for contamination on skin as well as from radioactive particles deposited onto ground, walls and roofs (external exposure) in the city center. It should be noted that the deposition pattern in urban areas varies greatly which means that the consequences are difficult to predict. The dispersion is influenced by recirculation behind tall buildings and diverted flow close to street-ends, which have significant effects on the deposit pattern. Regarding the relative importance of contributions to total dose it is found that inhalation could play a major role for long term effects while dose to skin might dominate acute effects.
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41.
  • Jönsson, Mattias, et al. (author)
  • Modelling the external radiation exposure from the Chernobyl fallout using data from the Swedish municipality measurement system
  • 2017
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 178-179, s. 16-27
  • Journal article (peer-reviewed)abstract
    • In connection with the Chernobyl fallout and the subsequent deposition of radionuclides in Sweden, Swedish municipalities launched a measurement program to monitor the external radiation exposure. This program encompasses measurements of the ambient dose equivalent rate 1 m above ground at selected locations, and repeats those measurements at the same locations at 7-month intervals. Measurement data compiled from the seven locations with the highest deposition were combined with data from aerial surveys since May 1986 of ground deposition of 137Cs, high-resolution gamma spectrometry performed at four locations in May 1986, and measurements from fixed continuous air gamma rate monitoring stations from 28 April to 15 May 1986. Based on these datasets, a model of the time pattern of the external dose rate in terms of ambient dose equivalent rate from the Chernobyl fallout was developed. The decrease in the ambient dose equivalent rate could, on average, be described by a four-component exponential decay function with effective half-times of 6.8 ± 0.3 d, 104 ± 26 d, 1.0 ± 0.02 y and 5.5 ± 0.09 y, respectively. The predominant contributions to the external dose rate in the first month were from short-lived fission products superseded by 134Cs and then 137Cs. Integrated over 70 y and using extrapolation of the curve fits, our model predicts that 137Cs contributes about 60% and 134Cs contributes about 30% of the external effective dose at these seven locations. The projected time-integrated 70 y external effective dose to an unshielded person from all nuclides per unit total activity deposition of 137Cs is estimated to be 0.29 ± 0.0.08 mSv/(kBq m-2). These results are in agreement with those found in Chernobyl contaminated Russian forest areas, and emphasize the usefulness of maintaining a long-term and regular measurement program in contaminated areas.
  •  
42.
  • Keogh, Sinead, et al. (author)
  • Trends in the spatial and temporal distribution of 129I and 99Tc in coastal waters surrounding Ireland using Fucus vesiculosus as a bio-indicator
  • 2007
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 95:1, s. 23-38
  • Journal article (peer-reviewed)abstract
    • Spatial and temporal trends in 129I and 99Tc concentrations around the Irish coastline have been evaluated using Fucus vesiculosus as a bio-indicator. 129I concentrations in a recent set of seawater samples have also been recorded and reveal an identical spatial pattern. Concentrations of 129I in Fucus from the northeast coast of Ireland proved to be at least two orders of magnitude higher than concentrations in Fucus from the west coast. The 129I content of Fucus increased significantly between 1985 and 2003, in line with increases in discharges of 129I from the Sellafield nuclear reprocessing plant. Similar trends were observed in the case of 99Tc. 129I/99Tc ratios in Irish seawater were deduced from the Fucus data, and compared to ratios in discharges from Sellafield and from the French reprocessing plant at Cap de la Hague. Levels of 129I and 99Tc in Fucus from the west coast were found to be enhanced with respect to levels in seaweeds from other regions in the Northern Hemisphere unaffected by discharges from nuclear installations such as those referred to.
  •  
43.
  • Kock, Peder, et al. (author)
  • Comparison of airborne and terrestrial gamma spectrometry measurements - evaluation of three areas in southern Sweden.
  • 2011
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 102:6, s. 605-613
  • Journal article (peer-reviewed)abstract
    • The Geological Survey of Sweden (SGU) has been conducting airborne gamma spectrometry measurements of natural radioactivity in Sweden for more than 40 years. Today, the database covers about 80% of the country's land surface. This article explores the first step of putting this data into use in radioactive source search at ground level. However, in order to be able to use the airborne background measurements at ground level, SGU data must be validated against terrestrial data. In this work, we compare the SGU data with data measured by a portable backpack system. This is done for three different areas in southern Sweden. The statistical analysis shows that a linear relationship and a positive correlation exist between the air and ground data. However, this linear relationship could be revealed only when the region possessed large enough variations in areal activity. Furthermore, the activity distributions measured show good agreement to those of SGU. We conclude that the SGU database could be used for terrestrial background assessment, given that a linear transfer function is established.
  •  
44.
  • Kock, Peder, et al. (author)
  • On background radiation gradients - the use of airborne surveys when searching for orphan sources using mobile gamma-ray spectrometry
  • 2014
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 128, s. 84-90
  • Journal article (peer-reviewed)abstract
    • Systematic background radiation variations can lead to both false positives and failures to detect an orphan source when searching using car-borne mobile gamma-ray spectrometry. The stochastic variation at each point is well described by Poisson statistics, but when moving in a background radiation gradient the mean count rate will continually change, leading to inaccurate background estimations. Airborne gamma spectrometry (AGS) surveys conducted on the national level, usually in connection to mineral exploration, exist in many countries. These data hold information about the background radiation gradients which could be used at the ground level. This article describes a method that aims to incorporate the systematic as well as stochastic variations of the background radiation. We introduce a weighted moving average where the weights are calculated from existing AGS data, supplied by the Geological Survey of Sweden. To test the method we chose an area with strong background gradients, especially in the thorium component. Within the area we identified two roads which pass through the high-variability locations. The proposed method is compared with an unweighted moving average. The results show that the weighting reduces the excess false positives in the positive background gradients without introducing an excess of failures to detect a source during passage in negative gradients. (C) 2013 Elsevier Ltd. All rights reserved.
  •  
45.
  • Konovalenko, Lena, et al. (author)
  • Application of an ecosystem model to evaluate the importance of different processes and food web structure for transfer of 13 elements in a shallow lake
  • 2017
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 169, s. 85-97
  • Journal article (peer-reviewed)abstract
    • In environmental risk assessments of nuclear waste, there is need to estimate the potential risks of a large number of radionuclides over a long time period during which the environment is likely to change. Usually concentration ratios (CRs) are used to calculate the activity concentrations in organisms. However, CRs are not available for all radionuclides and they are not easily scalable to the varying environment. Here, an ecosystem transport model of elements, which estimates concentrations in organisms using carbon flows and food transfer instead of CR is presented. It is a stochastic compartment model developed for Lake Eckarfjarden at Forsmark in Sweden. The model was based on available data on carbon circulation, physical and biological processes from the site and identifies 11 functional groups of organisms. The ecosystem model was used to estimate the environmental transfer of 13 elements (Al, Ca, Cd, CI, Cs, I, Ni, Nb, Pb, Se, Sr, Th, U) to various aquatic organisms, using element-specific distribution coefficients for suspended particles (K-d PM) and upper sediment (K-d sed), and subsequent transfer in the foodweb. The modelled CRs for different organism groups were compared with measured CRs from the lake and literature data, and showed good agreement for many elements and organisms, particularly for lower trophic levels. The model is, therefore, proposed as an alternative to measured CR, though it is suggested to further explore active uptake, assimilation and elimination processes to get better correspondence for some of the elements. The benthic organisms (i.e. bacteria, microphytobenthos and macroalgae) were identified as more important than pelagic organisms for transfer of elements to top predators. The element transfer model revealed that most of the radionuclides were channelled through the microbial loop, despite the fact that macroalgae dominated the carbon fluxes in this lake. Thus, element-specific adsorption of elements to the surface of aquatic species, that may be food sources for organisms at higher trophic levels, needs to be considered in combination with generic processes described by carbon fluxes.
  •  
46.
  • Konovalenko, Lena, et al. (author)
  • Evaluation of factors influencing accumulation of stable Sr and Cs in lake and coastal fish
  • 2016
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 160, s. 64-79
  • Journal article (peer-reviewed)abstract
    • As a result of nuclear accidents and weapons tests, the radionuclides Cs-137 and Sr-90 are common contaminants in aquatic ecosystems. Concentration ratios (CR) based on concentrations of stable Cs and Sr in biota and media are used for the estimation of transfer of their radioisotopes for radiation dose calculations in environmental and human safety assessments. Available element-specific CRs vary by over an order of magnitude for similar organisms, thus affecting the dose estimates proportionally. The variation could be reduced if they were based on a better understanding of the influence of the underlying data and how that affects accumulation and potential biomagnification of stable Cs and Sr in aquatic organisms. For fish, relationships have been identified between water concentrations of K and CR of Cs-137, and between water concentrations of Ca and CR of Sr-90. This has not been confirmed for stable Cs and Sr in European waters. In this study, we analysed an existing dataset for stable Cs and Sr, as well as K and Ca, in four Swedish lakes and three Baltic Sea coastal areas, in order to understand the behaviour of these elements and their radioisotopes in these ecosystems. We found significant seasonal variations in the water concentrations of Cs, Sr, K and Ca, and in electrical conductivity (EC), especially in the lakes. CR values based on measurements taken at single or few time points may, therefore, be inaccurate or introduce unnecessarily large variation into risk assessments. Instead, we recommend incorporating information about the underlying variation in water concentrations into the CR calculations, for example by using the variation of the mean. The inverse relationships between fish CRCs -[K](water) and fish CRSr-[Ca](water), confirmed that stable Cs and Sr follow the same trends as their radioisotopes. Thus, they can be used as proxies when radioisotope data are lacking. EC was also strongly correlated with K and Ca concentrations in the water and could potentially be used as a quick and cost-effective method to estimate water chemistry to obtain less variable CR. We also recommend some simple improvements to data collection that would greatly enhance our ability to understand Cs and Sr uptake by fish.
  •  
47.
  • Konovalenko, Lena, et al. (author)
  • Radionuclide transfer in marine coastal ecosystems, a modelling study using metabolic processes and site data
  • 2014
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 133, s. 48-59
  • Journal article (peer-reviewed)abstract
    • This study implements new site-specific data and improved process-based transport model for 26 elements (Ac, Ag, Am, Ca, Cl, Cm, Cs, Ho, I, Nb, Ni, Np, Pa, Pb, Pd, Po, Pu, Ra, Se, Sm, Sn, Sr, Tc, Th, U, Zr), and validates model predictions with site measurements and literature data. The model was applied in the safety assessment of a planned nuclear waste repository in Forsmark, Oregrundsgrepen (Baltic Sea). Radionuclide transport models are central in radiological risk assessments to predict radionuclide concentrations in biota and doses to humans. Usually concentration ratios (CRs), the ratio of the measured radionuclide concentration in an organism to the concentration in water, drive such models. However, CRs vary with space and time and CR estimates for many organisms are lacking. In the model used in this study, radionuclides were assumed to follow the circulation of organic matter in the ecosystem and regulated by radionuclide-specific mechanisms and metabolic rates of the organisms. Most input parameters were represented by log-normally distributed probability density functions (PDFs) to account for parameter uncertainty. Generally, modelled CRs for grazers, benthos, zooplankton and fish for the 26 elements were in good agreement with site-specific measurements. The uncertainty was reduced when the model was parameterized with site data, and modelled CRs were most similar to measured values for particle reactive elements and for primary consumers. This study clearly demonstrated that it is necessary to validate models with more than just a few elements (e.g. Cs, Sr) in order to make them robust. The use of PDFs as input parameters, rather than averages or best estimates, enabled the estimation of the probable range of modelled CR values for the organism groups, an improvement over models that only estimate means. Using a mechanistic model that is constrained by ecological processes enables (i) the evaluation of the relative importance of food and water uptake pathways and processes such as assimilation and excretion, (ii) the possibility to extrapolate within element groups (a common requirement in many risk assessments when initial model parameters are scarce) and (iii) predictions of radionuclide uptake in the ecosystem after changes in ecosystem structure or environmental conditions. These features are important for the longterm (>1000 year) risk assessments that need to be considered for a deep nuclear waste repository.
  •  
48.
  • Kulan, Abdulhadi (author)
  • Seasonal Be-7 and Cs-137 activities in surface air before and after the Chernobyl event
  • 2006
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 90:2, s. 140-150
  • Journal article (peer-reviewed)abstract
    • Seasonal fluctuations of cosmogenic Be-7 (T-1/2=53.4 days) and anthropogenic Cs-137 (T-1/2 = 30 years) activities in surface air (aerosols) have been extracted from a long data record (1972-2000) at high latitude (56 degrees N-68 degrees N, Sweden). Normalization to weekly average values was used to control long-term trends so that cyclical trends could be investigated. Enhanced Be-7 activity was observed in spring and summer seasons and likely relates to the seasonal thinning of the tropopause. Variations in the Cs-137 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 Cs-137 activity was strongly related to nuclear weapons test fallout and exhibits temporal fluctuations resembling the Be-7. Conversely, since 1986 the Chernobyl-produced Cs-137 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 (CS)-C-137 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.
  •  
49.
  • Laturnus, Frank, et al. (author)
  • Chloride - a precursor in the formation of volatile organochlorines by forest plants?
  • 2008
  • In: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 99:1, s. 119-125
  • Journal article (peer-reviewed)abstract
    • Two plants, a fern (Athyrium filix-femina) and a moss (Polytrichum commune Hedw.), both commonly occurring in Northern Temperate forests, were exposed in a laboratory study to a solution of 36Cl-chloride. The uptake of 36Cl-chloride by the plants was investigated and the emission of volatile chlorine 36 by the plants was determined. Furthermore, speciation of the emitted volatile organochlorine compounds (VOCls) was investigated. For the fern and the moss a rapid uptake of 36Cl-chloride was observed within a 1-h exposure period. The uptake rates for the fern and the moss, respectively, were 16 µg 36Cl-chloride g-1 fresh weight (FW) h-1 and 3.0 µg 36Cl-chloride g-1 FW h-1, respectively. The study also suggested that after uptake by the plants 36Cl-chloride is incorporated into VOCls, which were emitted by the plants into the atmosphere. Speciation analysis of the VOCls revealed the emission of chloroform, tetrachloromethane and 1,1,1-trichloroethane. © 2007 Elsevier Ltd. All rights reserved.
  •  
50.
  • Lidman, Fredrik, et al. (author)
  • Distribution and transport of radionuclides in a boreal mire : assessing past, present and future accumulation of uranium, thorium and radium
  • 2013
  • In: Journal of Environmental Radioactivity. - : Elsevier. - 0265-931X .- 1879-1700. ; 121, s. 87-97
  • Journal article (peer-reviewed)abstract
    • The spatial distribution of U-238, Ra-226, K-40 and the daughters of Th-232, Ra-228 and Th-228, were measured in a small mire in northern Sweden. High activity concentrations of U-238 and Th-232 (up to 41 Bq U-238 kg(-1)) were observed in parts of the mire with a historical or current inflow of groundwater from the surrounding till soils, but the activities declined rapidly further out in the mire. Near the outlet and in the central parts of the mire the activity concentrations were low, indicating that uranium and thorium are immobilized rapidly upon their entering the peat. The Ra-226 was found to be more mobile with high activity concentrations further out into the mire (up to 24 Bq kg(-1)), although the central parts and the area near the outlet of the mire still had low activity concentrations. Based on the fluxes to and from the mire, it was estimated that approximately 60-70% of the uranium and thorium entering the mire currently is retained within it. The current accumulation rates were found to be consistent with the historical accumulation, but possibly lower. Since much of the accumulation still is concentrated to the edges of the mire and the activities are low compared to other measurements of these radionuclides in peat, there are no indications that the mire will be saturated with respect to radionuclides like uranium, thorium and radium in the foreseen future. On the contrary, normal peat growth rates for the region suggest that the average activity concentrations of the peat currently may be decreasing, since peat growth may be faster than the accumulation of radionuclides. In order to assess the total potential for accumulation of radionuclides more thoroughly it would, however, be necessary to also investigate the behaviour of other organophilic elements like aluminium, which are likely to compete for binding sites on the organic material. Measurements of the redox potential and other redox indicators demonstrate that uranium possibly could be reduced in parts of the mire. The results of the study suggest that this mire currently is, and historically has been, an important sink for radionuclides and that it most likely will continue to be so for a long time to come.
  •  
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