| 51. |
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| 52. |
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| 53. |
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| 54. |
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| 55. |
- Martinsson, Johan, et al.
(författare)
-
Decontamination efficiency and waste generation for the decontamination of radioactively contaminated urban and rural environments
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A radioactive fallout following a nuclear accident can result in contamination of large areas of land. In order to protect human health against ionizing radiation, large-scale decontamination that includes multiple sets of clean-up measures may be necessary. Sweden lacks national experience of this type of large-scale decontamination. There are thus great uncertainties in the effect of such a decontamination which is dependent on the efficiency and waste generation of the individual remediation measures. In this report, the results from a literature review of the Japanese experience of decontamination after the nuclear accident in Fukushima-Daiichi, 2011, are highlighted. We show that the Japanese decontamination efficiency was on average about 12 percentage points lower than the decontamination efficiencies listed in reference literature on radioactive material decontamination. Removed contaminated soil is by far the largest contribution to radioactive waste production during decontamination. There is a positive correlation between reduced radiation dose rate and amount of soil removed during decontamination. Over time, however, ecological processes contribute by far the most to reduced radiation dose rates. The results can be an important contribution to current decontamination strategies and valuable for responsible agencies and authorities in the case of nuclear fallout incident.
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| 56. |
- Martinsson, Johan, et al.
(författare)
-
Experimental wildfire induced mobility of radiocesium in a boreal forest environment
- 2021
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697. ; 792
-
Tidskriftsartikel (refereegranskat)abstract
- Wildfires are expected to increase with warmer climate, which can contribute to the mobility and the resuspension of long-lived and potentially hazardous radionuclides. The release of 137Cs during combustion of dried litter, forest floor organic soil, and peat was investigated in a small-scale experimental set-up. Combustion conditions were varied to simulate different wildfire scenarios, and the fuels were dried organic material collected in a boreal environment of Sweden that was contaminated following the Chernobyl accident in 1986. The combustion-related release of 137Cs to the air was on average 29% of the initial fuel content, while 71% of the initial 137Cs remained in the ashes after the combustion. Peat and forest soil had the highest releases (39% and 37%, respectively), although these numbers should be viewed as potential releases since authentic wildfire combustion of these fuels are usually less effective than observed in these experiments. These results indicates that the 137Cs has migrated downwards in the organic material, which imply potentially significantly more 137Cs emissions in severe wildfires with intense combustion of the organic vertical profile in peatbogs and forests. More 137Cs tended to be released during intense and efficient combustion processes, although no significant differences among combustion intensities were observed. The generated experimental data was used in an emission scenario to investigate the possible range in 137Cs emissions from a wildfire. Our study shows that a severe wildfire in a contaminated area of 10,000 ha could potentially release up to 7 TBq of 137Cs. This is the first laboratory study to investigate 137Cs release upon varying combustion conditions using real fallout contaminated organic material obtained from a boreal environment.
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| 57. |
- Martinsson, Johan, et al.
(författare)
-
Influence of variable oxygen concentration on the combustion derived release of radiocesium from boreal soil and peat
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 815
-
Tidskriftsartikel (refereegranskat)abstract
- Radiocesium, 137Cs, is one of the most common and dispersed human-made radionuclides. Substantial stocks of 137Cs are stored in organic layers, like soils and peat, as a consequence of nuclear weapons fallout and accidental releases. As climate warming progresses these organic layers are subject to enhanced risks of wildfires, especially in the vast boreal biome of the northern hemisphere. Reemission of 137Cs to the atmosphere is therefore presumed to increase. Here, we experimentally investigated the emissions and redistribution of 137Cs in smoldering fires of boreal soil and peat by varying the oxygen concentration during combustion. For both soil and peat, significantly more 137Cs was released through flaming combustion in 21% O2 (50% and 31%, respectively) compared to smoldering in reduced O2 environments (14% and 8%, respectively). The residual ashes were heavily enriched (>100%) in 137Cs. Hence, after a wildfire induced volatilization of 137Cs, there exists further pathways of 137Cs enriched ash to proliferate in the environment. These results serve as a link between wildfire combustion conditions and the mobility of the 137Cs inventory found in ground fuels of the boreal environment and can be valuable for radiological risk assessments in a warmer and a more nuclear energy reliant world.
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| 58. |
- Nilsson, Jonas, et al.
(författare)
-
Investigation and optimisation of mobile Nal(Tl) and He-3-based neutron detectors for finding point sources
- 2015
-
Ingår i: Nuclear Instruments & Methods in Physics Research. Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment. - : Elsevier BV. - 0167-5087 .- 0168-9002. ; 786, s. 127-134
-
Tidskriftsartikel (refereegranskat)abstract
- Neutron radiation produces high-energy gamma radiation through (n,gamma) reactions in matter. This can be used to detect neutron sources indirectly using gamma spectrometers. The sensitivity of a gamma spectrometer to neutrons can be amplified by surrounding it with polyvinyl chloride (PVC). The hydrogen in the PVC acts as a moderator and the chlorine emits prompt gammas when a neutron is captured. A 4.7-l He-3-based mobile neutron detector was compared to a 4-1 NOM-detector covered with PVC using this principle. Methods were also developed to optimise the measurement parameters of the systems. The detector systems were compared with regard to their ability to find (AmBe)-Am-241, (CI)-C-252 and Pu-238-C-13 neutron sources. Results from stationary measurements were used to calculate optimal integration times as well as minimum detectable neutron emission rates. It was found that the 3He-based detector was more sensitive to Cf-252 sources whereas the Nal(TI) detector was more sensitive to (AmBe)-Am-241 and Pu-238-C-13 sources. The results also indicated that the sensitivity of the detectors to sources at known distances could theoretically be improved by 60% by changing from fixed integration times to list mode in mobile surveys. (C) 2015 Elsevier B.V. All rights reserved.
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| 59. |
- Nilsson, Jonas M.C., et al.
(författare)
-
A rotating-slit-collimator-based gamma radiation mapper
- 2017
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X. ; 177, s. 225-232
-
Tidskriftsartikel (refereegranskat)abstract
- For situations with radioactive material out of control where it may be physically difficult or prohibited to access areas close to the source, measurements from distance may be the only way to assess the radiation environment. Using collimated detectors will provide means to locate the direction of the radiation from the source. To investigate the possibilities of mapping gamma emitting radioactive material in a closed non-enterable area, a tentative system for mapping radioactive materials from a distance was built. The system used a computer controlled cylindrical rotating slit collimator with a high purity germanium detector placed in the cylinder. The system could be placed on a car-towed trailer, with the centre of the detector about 1.4 m above ground. Mapping was accomplished by the use of a specially developed image reconstruction algorithm that requires measurements from two or more locations around the area to be investigated. The imaging capability of the system was tested by mapping an area, 25 by 25 m2, containing three 330 MBq 137Cs point sources. Using four locations outside the area with about 20 min measuring time in each location and applying the image reconstruction algorithm on the deconvoluted data, the system indicated the three source locations with an uncertainty of 1–3 m. The results demonstrated the potential of using collimated mobile gamma radiometry combined with image reconstruction to localize gamma sources inside non-accessible areas.
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| 60. |
- Nilsson, Jonas, et al.
(författare)
-
Tests of HPGe- and scintillation-based backpack γ-radiation survey systems.
- 2014
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 135:Apr 24, s. 54-62
-
Tidskriftsartikel (refereegranskat)abstract
- The performance of three different backpack-mounted γ-radiation survey systems has been investigated. The systems are based on a LaBr3:Ce detector and a NaI(Tl) detector both with active volume dimensions of 76.2 mm in diameter and 76.2 mm length and a 123% relative efficiency HPGe detector. The detection limits of the systems were tested in a controlled outdoor environment in Sweden, followed by field tests of the HPGe- and LaBr3:Ce-based systems at the site of a radioactive waste repository in Georgia (in the Caucasus region of Eurasia). The results showed that the high efficiency HPGe detector performed significantly better than similar sized LaBr3:Ce and NaI(Tl) detectors, however, the HPGe detector was significantly heavier than the other systems. The use of different analysis methods revealed that creating maps of the survey area was the best method for offline analysis of survey data collected from a large area. Using off-site personnel for analysis of the data proved to be beneficial.
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| 61. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
-
Evaluation of the region-specific risks of accidental radioactive releases from the European Spallation Source
- 2021
-
Ingår i: Medical Physics in the Baltic States : Proceedings of the 15th International Conference on Medical Physics - Proceedings of the 15th International Conference on Medical Physics. - 1822-5721. ; , s. 142-146
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range ofradionuclides that could be released into the environment. Some radionuclides are of particular concern such as the rare earth gadolinium-148. In this article, the local environment was investigated in terms of food production and rare earth element concentration in soil. The collected data will later be used to model thetransfer of radioactive contaminations from the ESS.
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| 62. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
-
How to detect radionuclides specific to the European Spallation Source in soil samples?
- 2023
-
Ingår i: Medical Physics in the Baltic States (2023) : Proceedings of the 16th International Conference on Medical Physics - Proceedings of the 16th International Conference on Medical Physics. ; , s. 115-120
-
Konferensbidrag (refereegranskat)abstract
- The European Spallation Source (ESS) is a neutron research facility under construction in southern Sweden. The facility will produce a wide range of radionuclides including 148Gd, 187W, 172Hf, 182Ta and 178nHf that could be released into the environment in an accident scenario. Detection limits for these contaminants in soil were estimated to be in the mg k-1 range for ICP-MS and <3 Bq per 200 ml soil for gamma-ray spectroscopy.
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| 63. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
-
Investigation of the limits of detection for specific radionuclides in soil from the European Spallation Source (ESS) using radiometric and mass spectrometric methods
- 2023
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- This study provides information about the concentration of Tungsten (W), Hafnium (Hf) and Tantal (Ta) in the ESS soil and recommendations on the most appropriate sample preparation and measurement technique to assess contamination by these elements. The current levels of W, Hf and Ta measured in this study are in agreement with the estimated values from previous geological surveys. ICP MS showed low limits of detection for W, Hf and Ta and is thus an appropriate technique for environmental monitoring. However, the three metals are difficult to extract from soil and require the use of specific sample preparation methods (based on hydrofluoric acid for example). The transfer of stable W, Hf and Ta from soil to plant is poorly known and only a handful of publications can be found that are relevant to the plants grown around the ESS. The transfer of the radioisotopes of W, Hf and Ta in particular to animals (and man) is even less studied. However, the existing articles indicate a fast excretion of radio-W and radio-Ta while the excretion is slow for radio-Hf.The Minimum Detectable Activity (MDA) for gamma emitter released from the ESS facility will depend not only on the performances of the detection equipment but also on the composition of tungsten target at the time of the release. The determination of limits of detection of ESS related gamma emitters was performed using a strategy based on simulation of spectra. Semi-synthetic gamma spectra were obtained by combining real soil measurements with simulated data for mixtures of ESS radionuclides using the software Nucleonica. The simulation of 187W spectra was used as a proof of concept for the method. With this approach, it is possible to estimate limits of detection by gamma spectroscopy for a given target composition. The limits of detection of four relevant radionuclides were successfully determined for two different compositions of the ESS target and at three different activity concentrations in soil.
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| 64. |
- Pédehontaa-Hiaa, Guillaume, et al.
(författare)
-
Region-specific radioecological evaluation of accidental releases of radionuclides from ESS
- 2021
-
Bok (refereegranskat)abstract
- Gadolinium-148 is one of the radionuclides of most concern that will be produced in the tungsten target of the European Spallation Source (ESS), as a by-product of the spallation reaction used by the facility to produce neutrons. Since 148Gd a pure alpha emitter, it is both very radiotoxic and difficult to measure. With its half-life of 75 years, it will remain in the environment for a long time if released from the facility during normal operation or after an accident. There are still uncertainties regarding the amounts that actually will be produced by spallation in the tungsten targets of the facility. As Gd-148 does not occur naturally in the environment, there is no information available about its analysis in environmental samples but a few studies provide data from irradiated target material analysed by alpha spectroscopy or inductively coupled plasma mass spectrometry (ICP-MS). This report is a continuation of the SSM project as described in the SSM report 2020:08, entitled “Identifying radiologically important ESS-specific radionuclides and relevant detection methods” that focused on the ESS-related radionuclides that will be the most relevant to study and monitor in the environment as well as the analytical techniques to detect them. The present report focuses on the rare earth elements (REEs), including their radioactive isotopes, in particular Gd-148, and is intended to highlight the knowledge gaps that exist regarding their fate in the specific environment of the ESS area. In the first part of the report, the available literature on radioecological models was reviewed, with emphasis on ESS-related radionuclides. The existing modelling programmes were surveyed as well as the most relevant environmental parameters and experimental radioecological data required to build models specific to the ESS.In the second part of the report, the area in the vicinity of the ESS was surveyed to identify the important producers of foodstuff, what plant species are grown in the area and also the local husbandry and hunting practices, in order to identify critical pathways after a radioactive dispersion into the environment in connection with a potential accident at the ESS. In the third part of this report, after a thorough literature review and preliminary assays, we propose to investigate the use of ICP-MS for assessment of Gd-148 in the event of an accidental release, knowing that this analytical technique is already used for the measurement of stable Gd and REEs in the environment. The existing methods to extract REEs from environmental samples (soil, water, plants, and animal products) and to properly assess their concentration are described in the form of a literature review. The presented examples of methods were selected to fit the type of environment found around the ESS facility and the local agricultural and horticultural practices. A pilot study was also conducted to test extraction and measurement methods on the specific type of soil around ESS. These results are presented at the end of this report.
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| 65. |
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| 66. |
- Rääf, Christopher, et al.
(författare)
-
Body burden and excretion of 137-Cs and 40K in subjects from the south of Sweden
- 2000
-
Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 47:1, s. 83-100
-
Tidskriftsartikel (refereegranskat)abstract
- The equivalent biological half-times, Te, of 137Cs and 40K in a South-Swedish urban population have been determined through whole-body measurements and urinary excretion analysis. The Te - values for 137Cs found in males were on average, significantly lower than what is given in the literature. The relatively low average whole-body content of 40K,QK, in the males could explain the discrepancy, taking into consideration that a positive correlation between the Te and QK has been suggested in an earlier work. Furthermore, the potassium-normalized caesium urinary excretion was determined for the subjects in the study, and values were found to be in accordance with earlier results. A literature study of previous experimental data on the potassium-normalized caesium excretion however raises some questions about its applicability as a method for estimating the whole-body burden of 137Cs through urine analysis.
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| 67. |
- Rääf, Christopher, et al.
(författare)
-
Calculation models for the transfer of radioactive substances from a deep repository for spent nuclear fuel to the biosphere
- 2001
-
Ingår i: Kunskapsläget på kärnavfallsområdet 2001: rapport. - 0375-250X. - 9138214466 ; :35, s. 257-318
-
Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- This chapter summarizes the state of knowledge about models which describe how radioactive substances from a geological repository can be transferred through ecosystems to flora, fauna and mankind. Radionuclide migration to the biosphere and to man primarily occurs via groundwater flows passing through the repository. For such migration to occur, the integrity of the repository barrier system must be breached, for example, due to manufacturing defects in the copper canisters containing the spent nuclear fuel or as a result of long-term corrosion in the canister or due to other canister defects. The groundwater is connected to various water systems such as wells, marshes and wetlands, lakes, water courses as well as coastal and sea waters. The groundwater can also contaminate cultivated land via groundwater transport to the cultivation zone and via irrigation. The dilution volumes in the various water systems of the biosphere largely determine the consequences from leakage from a deep repository for spent nuclear fuel in the form of radiation doses to man and animals. Another exposure pathway from a deep repository to man is via bottom sediment in seas and lakes which, after future land rise, may dry up and later be cultivated to produce foodstuffs.
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| 68. |
|
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| 69. |
- Rääf, Christopher, et al.
(författare)
-
Ecological half-time of radiocesium from Chernobyl debris and from nuclear weapons fallout as measured in a group of subjects from the south of Sweden
- 2001
-
Ingår i: Health Physics. - 1538-5159. ; 81:4, s. 366-377
-
Tidskriftsartikel (refereegranskat)abstract
- From 1960 to 1980 and between 1987 and 1994 the whole-body content of 17Cs, and when possible also 134Cs, was measured in a group of subjects living in the city of Lund, Sweden (55.7 degrees N, 13.2 degrees E). The results have been analyzed to estimate the effective ecological half-time of fallout radiocesium in humans living in the area. The Lund area (The Province of Skane) was subjected to a deposition of about 2 kBq m(-2) of pre-Chernobyl 137Cs from nuclear weapons testing and 1 kBq m(-2) of 137Cs from Chernobyl fallout in May 1986. The radiocesium from the nuclear weapons tests in the 1950's and 1960's still gave a significant contribution to the total 137Cs levels in humans in the post-Chernobyl study period (1987-1994) of about 0.4 Bq per kg body weight, which was about 10% of the peak post-Chernobyl concentration level of 137Cs (3.5-4 Bq kg(-1)) in 1987. The effective ecological half-time for 137Cs from Chernobyl was found to be 1.8 +/- 0.2 y. The aggregate transfer factor from deposition to mean activity concentration in man was estimated to be 3.6 Bq kg(-1)/kBq m(-2). These values may be compared with an effective ecological half-time of 1.3 y found in the reference group in the 1960's, and an aggregate transfer factor of 10 Bq kg(-1)/kBq m(-2). This difference is largely explained by the continuous nature of the global fallout leading to contamination on growing crops whereas the Chernobyl fallout occurred just prior to the South Swedish growing season, leading to less efficient transfer to crops and to human diet. The average committed individual effective dose (50 y) from ingested 137Cs from the Chernobyl fallout was estimated to be 0.02 mSv and from the nuclear weapons fallout (1945-1995) to be 0.20 mSv.
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| 70. |
- Rääf, Christopher, et al.
(författare)
-
Environmental radioactivity and emergency preparedness
- 2016. - 1st edition
-
Bok (populärvet., debatt m.m.)abstract
- Radioactive sources such as nuclear power installations can pose a great threat to both humans and our environment. How do we measure, model and regulate such threats? Environmental Radioactivity and Emergency Preparedness addresses these topical questions and aims to plug the gap in the lack of comprehensive literature in this field.The book explores how to deal with the threats posed by different radiological sources, including those that are lost or hidden, and the issues posed by the use of such sources. It presents measurement methods and approaches to model and quantify the extent of threat, and also presents strategies for emergency preparedness, such as strategies for first-responders and radiological triage in case an accident should happen.Containing the latest recommendations and procedures from bodies such as the IAEA, this book is an essential reference for both students and academicians studying radiation safety, as well as for radiation protection experts in public bodies or in the industry
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| 71. |
- Rääf, Christopher, et al.
(författare)
-
Gamma Spectrometry
- 2022. - 1
-
Ingår i: Handbook of Nuclear Medicine and Molecular Imaging for Physicists : Instrumentation and Imaging Procedures - Instrumentation and Imaging Procedures. - 9781138593268 - 9780429489556 ; 1
-
Bokkapitel (refereegranskat)abstract
- Gamma spectrometry primarily is used for identification and quantification of gamma-emitting radionuclides present in samples collected from a specific environment. The objective is often to determine, with a certain confidence, whether the activity concentration of the present gamma emitters exceed some reference level: for example, a criterion for the highest level of impurity of gamma emitters in a radiopharmaceutical solution. Although medical physicists within nuclear medicine applications may often rely on the delivered radioactive solutions fulfilling quality criteria in terms of specified radionuclide content, it may nevertheless still be important to have access to, and sufficiently master, gamma-spectrometric assessments to make independent quality assurances. In this chapter a brief overview of gamma-spectrometric assessment is presented, with the aim of obtaining an understanding of the physical and computational fundamentals of this measurement procedure and the quality parameters used to characterize the performance of the assessment method. What prerequisites exist for setting up a gamma-spectrometry system, and what factors influence the precision and accuracy of the method? Furthermore, this chapter presents the basic procedures for maintaining a sufficient quality in the performance of the gamma spectrometry and also provides some examples of evaluation of gamma spectra.
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| 72. |
- Rääf, Christopher, et al.
(författare)
-
Hair as an indicator of the body content of polonium in humans: preliminary results from study of five male volunteers.
- 2015
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 141, s. 71-75
-
Tidskriftsartikel (refereegranskat)abstract
- The radionuclide (210)Po is of importance from a radiation protection view and has properties that cause special problems when attempting to determine the body content in humans. Estimates have traditionally been made from either urine and/or fecal samples, which require a time-consuming radiochemical preparation before alpha spectrometric determination. In order to find a more simple and less labor intensive method hair has been used as a bioindicator and investigated in this study. The relationship between intake and excretion in hair has been estimated in five volunteers who ingested radioactive polonium ((209)Po as a bio-tracer for (210)Po) in well determined quantities. Four of the volunteers were given 5-10Bq (209)Po in a single intake (acute intake) and one volunteer has ingested a daily intake of 58.7mBq (209)Po for a period of 180d. Human hair was found to reflect the daily clearance of ingested polonium peaking at 0.001-0.01%d(-1) of the ingested amount, thereafter decreasing mono-exponentially, corresponding to a biological half-time of 10-20 days. For the case of protracted intake a mono-exponential build-up was observed with a half-time of 40±5d. In addition, after cessation of intake, a short-term component (74%) with a biological half-time of 16±4d, and a long-term component (26%) with a half-time of 93±53d were observed. It is concluded that hair can be used to detect not only the amount of ingested polonium but also whether the intake was protracted or acute.
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| 73. |
- Rääf, Christopher
(författare)
-
Human Metabolism and Ecological Transfer of Radioactive Caesium
- 2000
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The whole-body content of radiocaesium was measured in a South-Swedish urban group of people residing in the city of Lund (55.7°N, 13.2°E) between 1960 and 1994. The results from the survey have been analysed in order to estimate the ecological half-time, Teco,eff, of fallout radiocaesium and the aggregate transfer from ground deposition to man in the region. After 1987, the biological half-times, Te, of 137Cs and 40K in man were also determined in the reference group through whole-body content measurements in combination with 24-hour urine sampling. Relationships between 24-hour urinary excretion and body burden of 137Cs in the group together with data from the literature were then applied to urine samples collected in 1994 and 1995 from adult subjects living in the highly contaminated region of Bryansk, Russia, in order to estimate their average body burden of 137Cs. The equivalent biological half-time for 137Cs in females of the Lund reference group was, on average (±1 WSE), 66±3 d, which agrees with other findings, whereas the value for the males, 81±4 d, was, on average, significantly lower than what is found in the literature. This is partly explained by the elevated mean age and relatively low mean body muscle mass of the males investigated in the group during the post-Chernobyl study period. The effective ecological half-time for 137Cs from Chernobyl was found to be 1.8± 0.2 y. The aggregate transfer of 137Cs from deposition to mean activity concentration in man was estimated to be 1.7 Bq kg-1/kBq m-2. These values may be compared with an effective ecological half-time of 1.3 years found in the reference group in the 1960s, and an aggregate transfer factor of 9.8 Bq kg-1/kBq m-2. The average committed effective dose from ingested 137Cs Chernobyl fallout in the study group was estimated to be 0.02 mSv and from the nuclear weapons fallout to 0.20 mSv. The estimates of whole-body content of 137Cs in the Russian subjects obtained through creatinine normalisation of the 137Cs content in urine were, on average, a factor of 2 higher than estimates obtained through a potassium normalisation procedure; 55±8 (1 SE) kBq for creatinine and 29±4 (1 SE) kBq for potassium normalisation in the year 1994. This was due to a significant difference in the relationship between the urinary potassium and creatinine concentration between the Swedish and Russian group. The elevated potassium concentration found in the rural Russian subjects indicated a higher dietary intake of potassium, which greatly influences the accuracy and applicability of the potassium normalisation method when estimating body burden of 137Cs through urine assay. It is therefore recommended not to use the potassium normalisation procedure in cases where the daily intake of potassium is unknown. The estimated body burden of 137Cs in the Bryansk group in 1994 corresponds to a contribution to the estimated annual effective dose of 1.8 mSv y-1, which is approximately 200 times greater than the average annual dose received from ingested 137Cs by the subjects of the Lund reference group during the period 1987-1994.
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| 74. |
- Rääf, Christopher, et al.
(författare)
-
Human metabolism of radiocaesium revisited
- 2004
-
Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 112:3, s. 395-404
-
Tidskriftsartikel (refereegranskat)abstract
- Three adult volunteers (2 males and I female) have ingested radioactive caesium in two edible forms in order to compare the gastrointestinal uptake and the subsequent short-term and long-term biokinetics. Foodstuffs made of fresh-water fish or mushrooms from regions in Sweden of high Cs-137 deposition was ingested together with a (CsCl)-Cs-134-solution mixed with soft drinks. Whole-body countings of Cs-134 and Cs-137 were performed in the Malmo whole-body counter during a period of similar to50 d prior to, and 200-300 d after the ingestion. Urine and faeces were collected the day before and up to 7-10 d after the test meals, and analysed for Cs-134 and Cs-137. No significant difference in the gastrointestinal uptake fraction, f(0) = 0.98 between caesium incorporated into a foodstuff matrix and caesium in ionic form was detected. Cumulated faecal excretion during 7 d after ingestion accounted for 2-3% of the intake. No significant difference in the long-term biological half-time was found between caesium present in a food matrix and in an aqueous solution in any of the volunteers.
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| 75. |
- Rääf, Christopher, et al.
(författare)
-
Introduction of a method to calculate cumulative age- And gender-specific lifetime attributable risk (LAR) of cancer in populations after a large-scale nuclear power plant accident
- 2020
-
Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 15:2
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of age and gender in risk estimates related to long-term residence in areas contaminated by nuclear power plant fallout was evaluated by applying the lifetime attributable risk (LAR) concept to an existing exposure model that was previously used for cumulative effective dose estimates. In this study, we investigated the influence of age distribution on the number of cancer cases by applying five different age distributions from nuclear power-producing countries (India, Japan, South Korea, and the United States), and Egypt because of intentions to develop nuclear power. The model was also used to estimate the effective dose and gender-specific LAR as a function of time after fallout for the offspring of the population living in 137Cs fallout areas. The principal findings of this study are that the LAR of cancer incidence (excluding non-fatal skin cancers) over 70 y is about 4.5 times higher for newborn females (5.4% per MBq m-2 of initial 137Cs ground deposition) than the corresponding values for 30 y old women (1.2% per MBq m-2 137Cs deposition). The cumulative LAR for newborn males is more than 3 times higher (3.2% versus 1.0% per MBq m-2 137Cs deposition). The model predicts a generally higher LAR for women until 50 y of age, after which the gender difference converges. Furthermore, the detriment for newborns in the fallout areas initially decreases rapidly (about threefold during the first decade) and then decreases gradually with an approximate half-time of 10-12 y after the first decade. The age distribution of the exposed cohort has a decisive impact on the average risk estimates, and in our model, these are up to about 65% higher in countries with high birth rates compared to low birth rates. This trend implies larger average lifetime attributable risks in countries with a highly proportional younger population. In conclusion, the large dispersion (up to a factor of 4 between newborns and 30 y olds) in the lifetime detriment per unit ground deposition of 137Cs over gender and age in connection with accidental nuclear releases justifies the effort in developing risk models that account for the higher radiation sensitivity in younger populations.
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| 76. |
- Rääf, Christopher L, et al.
(författare)
-
A Novel Swedish Master’s Degree Programme for Applied Radiation Protection.
- 2012
-
Ingår i: 13th International Congress of the International Radiation Protection Association (IRPA) in Glasgow, 13-18 May 2012.
-
Konferensbidrag (refereegranskat)abstract
- Since the beginning of the 1960s Sweden has had a university programme for Medical Radiation Physics. This programme was expanded to a MSc level, when it was redesigned (mid-2000s) to generate a professional license as a clinical medical physicist, warranted by the Swedish National Board of Health and Welfare. The main end-users for this programme have been i.) hospitals and clinics, and ii.) research departments. Nuclear industries and authorities associated with radiation protection and emergency preparedness did not always recruit students from this particular programme as it was focused on topics related to the hospital environment. In the beginning of the 2000s it was identified that Sweden, as many other countries, needed an additional and supplementary skill in radiation protection, to meet a new threat from nuclear and radiological events, also including malovent use of radioactvity. A new cadre of experts had to be formed with competence within radiation protection for non-hospital issues in the next generation. In accordance with this need for a new profession, here referred to as applied radiation protection, the Medical Physics departments at Lund University (ass. prof. C. L. Rääf) and Göteborg University (prof. M. Isaksson) were commissioned by the Swedish Radiation Protection Authority in 2008 to elaborate an educational programme on a Master’s level. This programme, Applied radition protection, has recently been accepted by the Sahlgrenska Academy board of basic education at Göteborg University and is presented here. The programme is 2 years, ending with a Master thesis (30 ECTS), containing six principal courses; i.) Basic radiation protection – an introductory course to fundamental radiation protection. ii.) Emergency preparedness and management in radiological or nuclear emergencies – focusing on the role of various authorities and stakeholders in the society. iii.) Detectors and measurement methods in applied radiation protection – introducing the most common types of detectors used in stationary and mobile radiometry systems, including also search strategies for localising lost radiation sources. iv.) On-site management of radiological and nuclerar events – consisting of practical field exercises performed together with rescue workers and first responders. v.) Management of patients subjected to radiation exposure in emergency situations – focusing on the medical treatment of patients, from damage site to special medicine, including practical exercises. vi.) Nuclear energy fuel cycle – an overview of the topic with special attention to radiation protection issues, including also nuclear weapons. This Master programme is planned to be launched in autumn 2012 and is open also for applications from foreign students. For those students that graduate and wish to deepen their skills and expertise in this field, several PhD projects will be offered.
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| 77. |
- Rääf, Christopher L., et al.
(författare)
-
Average uranium bedrock concentration in Swedish municipalities predicts male lung cancer incidence rate when adjusted for smoking prevalence: Indication of a cumulative radon induced detriment?
- 2023
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 855
-
Tidskriftsartikel (refereegranskat)abstract
- Bedrock U has been used as a proxy for local indoor radon exposure. A preliminary assessment of cancer incidence rate in a cohort of 809,939 adult males living in 9 different Swedish counties in 1986 has been used to correlate the cumulative lung cancer and total cancer (excluding lung) incidence rates between 1986 and 2020, respectively with the municipality average value of bedrock U concentration obtained from Swedish geological Survey (SGU). To control for regional difference in tobacco smoking, data on county average smoking prevalence, obtained from a survey conducted by the Public Health Agency of Sweden from 2001 to 2004, was used. Regression analysis shows that there is a significant positive correlation between smoking prevalence adjusted lung cancer incidence rate in males and the municipality bedrock U concentration (R2 = 0.273 with a slope 5.0 ± 0.87·10−3 ppm−1). The correlation is even more significant (R2 = 0.759 with a slope = 4.8 ± 0.25·10−3 ppm−1) when assessed on population weighted cancer incidence data binned in nine intervals of municipality average bedrock U concentration (ranging from 0.97 to 4.9 ppm). When assessing the corresponding correlations for total cancer incidence rate (excluding cancer of the lung) with adjustment for smoking prevalence, there appears to be no or little correlation with bedrock U concentration (R2 = 0.031). We conclude that an expanded future study needs age-standardized cancer incidence data to obtain a more consistent exposure-response model. Such model could be used to predict future lung cancer cases based on geological survey maps of bedrock U as an alternative to laborious indoor radon measurements, and to discern what future lung cancer rates can be expected for a population nearing zero smoking prevalence, with and without radon prevention. © 2022 The Authors
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| 78. |
- Rääf, Christopher L., et al.
(författare)
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Time‑dependence of decontamination efficiency after a fallout of gamma‑emitting radionuclides in suburban areas: a theoretical outlook on topsoil removal
- 2022
-
Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1
-
Tidskriftsartikel (refereegranskat)abstract
- Decontamination of urban areas may be necessary in the case of extensive fallout of radioactive material after a nuclear accident, as removal of contaminated soil and vegetation will significantly reduce doses for the residents in an area affected by fallout. Experience from Japan shows that cleanup operations of urban areas may take years despite investment in ample resources. The time delay between the initial fallout and completion of the decontamination measures allows natural and physical processes to affect the results. The efficiency of the decontamination will therefore depend significantly on time. Radioecological modeling and computer simulation of urban topography with one-story houses were applied in this study to estimate action-influenced time-integrated dose reductions (TDR) of contaminated topsoil removal as a function of time after the fallout. Results indicate that the TDR decreases gradually after the fallout depending on the vertical migration rate of radiocesium and, to some extent, the initial 134Cs/137Cs ratio. Delaying the topsoil removal from 1 to 10 years will result in a TDR decrease by more than a factor of two. Removing the topsoil within one year after fallout results typically in an averted effective dose between 34 and 80 mSv per MBq m− 2 deposition of 137Cs for residents in wooden houses. The corresponding values for residents in brick houses are about 50% lower due to higher shielding. Additional modeling is needed to estimate how age and sex influence the averted detriment to affected cohorts. In addition, more in-depth knowledge of how the efficiency of topsoil removal in practice compares with hypothetical models and the effect of incomplete removal of radiocesium is needed to improve calculations of TDR values.
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| 79. |
- Rääf, Christopher, et al.
(författare)
-
Restoring areas after a radioactive fallout : A multidisciplinary study on decontamination
- 2023
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier. - 0265-931X .- 1879-1700. ; 270
-
Tidskriftsartikel (refereegranskat)abstract
- Land remediation is an important part of restoration measures after a radioactive fallout containing long-lived fission products such as 137Cs. In this multidisciplinary study, we focused on three main issues related to remediation of contaminated urban areas. First, we assessed how much decontamination contributes to reducing resident radiation exposure and how much this reduction depends on the timing of implemented measures. Second, we calculated direct and indirect costs of decontamination in an industrialized country such as Sweden. Finally, in a survey study, we considered reactions of Swedish citizens to being given the hypothetical option of moving to a site decontaminated after radioactive fallout and how this predicted response might influence the design of contingency plans. The main findings are that clean-up operations must be done within the first few years after a fallout to contribute significantly to reducing residual dose. If conducted within 1-2 years, large-scale decontamination can, on average, avert 20-200 manSv per km2 residential area and unit ground deposition of 137Cs (1 MBq). The estimated direct costs (in 2020 purchasing power) would amount to 100 million Euro per km2 decontaminated residential area (comparable to Japanese estimates after the Fukushima accident), generating 39,000 m3 of radioactive waste on average, mainly in the form of 137Cs-contaminated topsoil. In our survey study of 2291 Swedish respondents about their willingness to return to decontaminated homes, women, families with resident children, and high-income earners exhibited more skepticism about returning, even if authorities were to deem it safe. The demographic pattern in attitudes was similar to that found among evacuees in the Fukushima prefecture after 2011. We conclude that predefined ranges of measured 137Cs ground deposition can be used as guidance for rescue leaders in the early post-accident phase in long-term planning for affected areas. This planning should include timing and intensity of decontamination measures, duration of evacuation, and risk communication to citizens. Because some citizens expressed both high risk perception and risk aversion, however, timely and dialogic communication is unlikely to limit a shift after the incident to an older and more male-dominated population composition. There is a risk that those who can afford to do so will move away, whereas people whose wealth is locked in property (houses or businesses) will feel stuck. Perceptions of unfairness may fray the social fabric and complicate resettlement, which in some cases may mean inefficient outlay of decontamination costs. We believe that the issue of monetary compensation to affected residents requires priority in future work.
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| 80. |
- Rääf, Christopher, et al.
(författare)
-
The first year of a Novel Swedish Master’s Degree Programme for Applied Radiation Protection
- 2014
-
Ingår i: The 4th European Regional IRPA Congress.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The education in medical radiation physics at university level in Sweden has a history from the early 1960s. Today, the programme consists of five years of studies. However, since the development in medical applications of radiation is so rapid there is little room in the schedule for giving the students a good training in radiation protection dealing with situations outside the medical sphere. It has been recognized by the Swedish Radiation Safety Authority, SSM, (among others) that there is a severe lack of experts in radiation protection concerning nuclear or radiological accidents and malicious use of radioactive sources. In accordance with this need for a new profession, here referred to as Applied radiation protection, the Medical Physics departments at Lund University (ass. prof. C. L. Rääf) and University of Gothenburg (prof. M. Isaksson) were commissioned by SSM in 2008 to elaborate an educational programme on a Master’s level. After some years of conceiving and launching new courses in radiation protection for national professional development (CPD) of medical physicists this Master programme started in fall 2012, with two courses at the Sahlgrenska Academy at the University of Gothenburg that were adapted from the CPD programme. “National emergency preparedness for radiation protection” focuses on the role of various authorities and stakeholders in the society. The course was given as a distance course with six mandatory meetings. During three days the students meet representatives from the authorities engaged in the emergency preparedness as lecturers. During these days, the course is run together with the medical physicists following the CPD-course of the same topic. “Radiation protection and environmental impact of the nuclear fuel cycle” was given later during fall 2012, also as a distance course, including three days combined with a CPD-course. Both courses on the master level were examined by calculation exercises and essays. During fall 2013 two more courses will be given: “Detectors and measurement methods in radiation protection and emergency preparedness” and “Radiation protection in medical emergency preparedness”, with the same structure as the courses above. Plans for the future involve making the courses in this Master programme in English, and thus open for international participants. There are also plans of running fragments of these courses together with the national specialist training of radiation protection staff within the nuclear industry, in order to provide them with lectures and seminars on an academic level as a part of their professional development. In return, such a collaboration would expand the Master programme into nuclear safety and reactor physics.
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| 81. |
- Rääf, Christopher, et al.
(författare)
-
Transfer of (137)Cs from Chernobyl debris and nuclear weapons fallout to different Swedish population groups.
- 2006
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 367:Feb 24, s. 324-340
-
Tidskriftsartikel (refereegranskat)abstract
- Data from measurements on the body burden Of (CS)-C-134, Cs-137 and K-40 in various Swedish populations between 1959 and 2001 has been compiled into a national database. The compilation is a co-operation between the Departments of Radiation Physics in Malmo and Goteborg, the National Radiation Protection Authority (SSI) and the Swedish Defense Research Agency (FOI). In a previous study the effective ecological half time and the associated effective dose to various Swedish populations due to internal contamination of Cs-134 and Cs-137 have been assessed using the database. In this study values of human body burden have been combined with data on the local and regional ground deposition of fallout from nuclear weapons tests (only Cs-137) and Chernobyl debris (both Cs-134 and (CS)-C-137), which have enabled estimates of the radioecological transfer in the studied populations. The assessment of the database shows that the transfer of radiocesium from Chernobyl fallout to humans varies considerably between various populations in Sweden. In terms of committed effective dose over a 70 y period from internal contamination per unit activity deposition, the general (predominantly urban) Swedish population obtains 20-30 mu Sv/kBq m(-2). Four categories of populations exhibit higher radioecological transfer than the general population; i.) reindeer herders (similar to 700 mu Sv/kBq m(-2)), ii.) hunters in the counties dominated by forest vegetation (similar to 100 mu Sv/kBq m(-2)), iii.) rural non-farming populations living in sub-arctic areas (40-150 mu Sv/kBq m(-2)), and iv.) farmers (similar to 50 mu Sv/kBq m(-2)). Two important factors determine the aggregate transfer from ground deposition to man; i.) dietary habits (intakes of foodstuff originating from natural and semi-natural ecosystems), and ii.) inclination to follow the recommended food restriction by the authorities. The transfer to the general population is considerably lower (similar to a factor of 3) for the Chernobyl fallout than during the 1960s and 70s, which is partly explained by a higher awareness of the pathways of radiocaesium to man both by the public and by the regulating authorities, and by the time-pattern of the nuclear weapons fallout during the growth season in Sweden. (c) 2005 Elsevier B.V. All rights reserved.
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| 82. |
- Rääf, Christopher, et al.
(författare)
-
Urinary excretion measurements for the assessment of body burden of radiocaesium in man: differences between potassium and creatinine normalisation
- 1999
-
Ingår i: Applied Radiation and Isotopes. - 0969-8043. ; 51:5, s. 505-514
-
Tidskriftsartikel (refereegranskat)abstract
- Relationships between 24-h urinary excretion and body burden of 137Cs obtained in a south-Swedish population, together with data from the literature, were applied to urine samples collected in 1994-95 from adult subjects living in Russia, in order to estimate their average body burden of 137Cs. Estimates obtained through creatinine normalisation of the 137Cs content in the Russian urine were a factor of 2 higher than estimates obtained through potassium normalisation. The accuracy of both these normalisation methods is discussed, as well as the influence of the difference in dietary habits between the two populations.
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| 83. |
- Rääf, Christopher, et al.
(författare)
-
Återställning av förorenade områden efter en RN-olycka : Samhällets problem och hur bästa kombination av långsiktiga åtgärder kan väljas för att skydda människor i bebyggda miljöer mot bestrålning
- 2022
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Detta projekt har syftat till att ge svenska myndigheter och beslutsfattare enbeskrivning av samhällets problem efter ett kraftigt nedfall av långlivade radioaktivaämnen och hur den bästa kombinationen av åtgärder kan väljas för att skyddamänniskor mot bestrålning med hänsyn till ekonomiska, sociala och samhälleligafaktorer. Arbetet med att återställning av ett tätortsområde som berörts av enomfattande radioaktiv beläggning från en kärnteknisk olycka är en process som kanta många år i anspråk. Initial krishantering av myndigheterna kommer successivtbehöva övergå till långsiktig kontinuerlig riskhantering av de personer som väljer attstanna kvar eller flytta tillbaka till det drabbade området. Denna långsiktigariskhantering kommer också beröra de utrymda personer som väljer att inteåtervända till det sanerade området.I projektet har berättigandet av saneringsåtgärder, samt vilka faktorer som styr huråtgärderna ska optimeras, studerats utifrån ett flervetenskapligt perspektiv.Slutsatserna är att marksanering av bebyggda områden kan vara berättigade ur ettsamhällsperspektiv trots de mycket höga monetära kostnaderna som åtgärdernakräver i relation till de avstyrda stråldoser och cancerfall som kan uppkomma.Möjlighet till återflytt av ett utrymt område styrs i hög grad av de dosvärden sommyndigheternas skyddsåtgärder syftar till att underskrida (s.k. referensnivåer) ochsom finns angivna i svensk myndighetsvägledning (SSM, 2017). Genommarksanering kan stråldoser minskas så att dessa referensnivåer underskrids ochdärmed möjliggöra återflytt till nedfallsdrabbade områden betydligt tidigare än ombara utrymning görs, förutsatt att saneringsåtgärderna görs enligt internationelltrekommenderade metoder.Sanering kan också utgöra en tydlig milstolpe i den långsiktiga riskhanteringen förboende i ett område som berörts av radioaktiv beläggning och utgöra ettplaneringsunderlag för de drabbade individernas fortsatta livsval och bearbetning avolyckan.
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| 84. |
- Samuelsson, Christer, et al.
(författare)
-
Decontamination after a nuclear fallout: A condensed review of case studies, methods and key references up to 2014
- 2019
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of this work is to provide governmental agencies and the society a condensed overview of the current state of knowledge on the efficiency of applied restoration and remediation of areas affected by radioactive fallout. The most actual real-world case is the Fukushima accident in Japan in 2011: the accident and the following applied decontamination methods are in focus in this review study. This report was written in 2014 and reviewed and translated in 2018/2019. This work was financed by the Swedish Civil Contingencies Agency.
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| 85. |
- Stenström, Kristina, et al.
(författare)
-
The use of hair as an indicator of occupational (14)C contamination.
- 2010
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 1432-2099 .- 0301-634X. ; 49:1, s. 97-107
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents a study in which the specific activity of (14)C in hair has been investigated as an easily determined bio-indicator of the integrated (14)C exposure (over several months). The study includes 28 Swedish workers handling (14)C-labelled compounds, or working in a (14)C-enriched environment. Hair samples from personnel at a Swedish nuclear power plant showed very low levels of (14)C contamination, if any. In contrast, personnel at the investigated research departments showed (14)C levels in hair of up to 60% above the natural specific activity of (14)C. Much higher levels, up to 80 times the natural specific activity of (14)C, were found in hair from individuals working at a pharmaceutical research laboratory. This contamination was, however, not solely an internal contamination. There were indications that most of the (14)C in the hair originated from airborne (14)C-compounds, which were adsorbed onto the hair. The difficulties in removing this external (14)C contamination prior to analysis are discussed, as are the possibilities of using accelerator mass spectrometry to analyse various types of samples for retrospective dose assessment.
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| 86. |
- Sundström, Jonathan, 1993, et al.
(författare)
-
Dose and risk calculation tool for simulation of countermeasures, aimed for training of, for example, decision makers not specialized in radiation protection
- 2023
-
Ingår i: NERIS Workshop, European Radiation Protection Week (ERPW), 9-13 October 2023, Dublin, Ireland.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 87. |
- Sundström, Jonathan, 1993, et al.
(författare)
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LARCalc, a tool to estimate sex‑ and age‑specific lifetime attributable risk in populations after nuclear power plant fallout
- 2023
-
Ingår i: Scientific Reports. - 2045-2322. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- A tool called LARCalc, for calculating the radiological consequences of accidental large scale nuclear power plant releases based on estimates of 137Cs ground deposition, is presented. LARCalc is based on a previously developed models that has been further developed and packaged into an easy-touse decision support tool for training of decision makers. The software visualises the radiological impact of accidental nuclear power plant releases and the effects of various protective measures. It is thus intended as a rapid alternative for planning protective measures in emergency preparedness management. The tool predicts projected cumulative effective dose, projected lifetime attributable cancer risk, and residual dose for some default accidental release scenarios. Furthermore, it can predict the residual dose and avertable cumulative lifetime attributable risk (LAR) resulting from various protective measures such as evacuation and decontamination. It can also be used to predict the avertable collective dose and the increase in cancer incidence within the specified population. This study presents the theoretical models and updates to the previous models, and examples of different nuclear fallout scenarios and subsequent protective actions to illustrate the potential use of LARCalc.
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| 88. |
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| 89. |
- Thomas, Rimon, et al.
(författare)
-
Natural radioactivity in a former mining lake in Central Sweden
- 2016
-
Ingår i: SweRays Workshop, Stockholm, Sweden, Aug 25-26.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Historically Sweden (the major metal mining country in the European Union), with more than 2700 mines, gathers around 30000 sites that have been minor mines and/or quarries (according to the database of Geological Survey of Sweden, SGU). This huge activity has implied enormous quantities of generated mining wastes, considered, in some cases NORM (Naturally Ocurring Radioactive Material). In this work, one former mine lake nearby Kolsva (in Västmanland) was radiometrically characterized. Water samples from the pit lake, sediment and soil/rock samples were measured via alpha (for 238U, 234U, 232Th and 230Th isotopes) and via gamma spectrometry (for radionuclides belonging to both 238U and 232Th natural series). Also measurement of elementary composition in water (via ICP-MS) and in sediments (via XRF) was carried out. Regarding 238U isotopes, for instance, 100 to 600 mBq/kg were found in water samples. Having into account that an average value of this isotope in non-affecting environmental waters is around 20-30 mBq/kg it is quite clear that this site has enhanced U levels in superficial waters. These moderated levels in natural radionuclides were also confirmed in some rocks from this site with values above 1Bq/g in natural radionuclides from 238U series. The found activity concentration values will contribute to increase the external doses received by people visiting these sites for recreation (swimming, fishing, diving) purposes. Keywords: Natural radionuclides, environmental samples, mining lakes
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| 90. |
- Tondel, Martin, et al.
(författare)
-
Cancer incidence in a male adult population in relation to estimated protracted colon dose – A nested case control study in Northern Sweden after the Chernobyl Nuclear Power Plant accident
- 2022
-
Ingår i: Science of the Total Environment. - : Elsevier BV. - 0048-9697 .- 1879-1026. ; 838:3
-
Tidskriftsartikel (refereegranskat)abstract
- Introduction: Uncertainty in the dose-response of low dose radiation raised concern of an increased cancer incidence in Sweden after the Chernobyl Nuclear Power Plant (NPP) accident. Material and methods: A closed cohort was created of all males ≥18 years of age living in the Northern Sweden in 1986. In total 826,400 individuals were enrolled including 40,874 hunters. A nested case-control design was used with five controls randomly selected for each cancer case matched on year of diagnosis and year of birth. Individual absorbed colon dose was calculated 1986 to 2015. Allowing for a 5-year latency period Hazard Ratios (HR) per mGy with 95%Confidence Intervals (95%CI) were calculated in a conditional logistic regression adjusted by rural/non-rural living, length of education and pre-Chernobyl cancer incidence 1980 to 1985. A total of 127,109 cancer cases occurred from 1 January 1991 to 31 December 2015. Cancer was classified in: 1) Organ-specific (stomach, colon, liver, lung, prostate, urinary bladder, thyroid and leukaemia), 2) Other and 3) Not previously associated to ionizing radiation. Results: The average colon dose in cases was 1.77 mGy compared to controls 1.73 mGy. Hunters average colon dose was 2.32 mGy. Organ-specific cancers showed the highest HR per mGy both in the full cohort, adj HR 1.019 (1.014–1.024) and the hunter subcohort, adj HR 1.014 (1.001–1.027) during follow-up 1991 to 2015. Other cancer and Not previously associated with ionizing radiation showed lower HR per mGy. Therefore, the adj HR per mGy for Total cancer, 1.013 (1.009–1.017) was explained by Organ-specific cancer. Increased adj HR per mGy was seen in stomach, colon and prostate cancer, respectively in the full cohort and lung cancer in hunters. Conclusions: Some cancer sites previously associated with ionizing radiation showed a positive adjusted HR per mGy both in the full cohort and in the hunter subcohort.
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| 91. |
- Tondel, Martin, et al.
(författare)
-
Dose–response analysis of protracted absorbed organ dose and site-specific cancer incidence in Sweden after the Chernobyl nuclear power plant accident
- 2023
-
Ingår i: Environmental Epidemiology. - : Lippincott Williams & Wilkins. - 2474-7882. ; 7:6
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Adult males in Sweden exhibit an increased risk of cancer associated with an increased absorbed dose to the colon from the Chernobyl accident. Methods: A closed cohort, with information on hunter status, included all individuals living in northern Sweden in 1986. Complete annual information on exposure to 137Cs at the dwelling coordinate was available for a total of 2,104,101 individuals. A nested case-control method with four controls matched for year of cancer diagnosis and year of birth, was used. Individual absorbed organ doses were calculated between 1986 and 2020 including external and internal exposure. Hazard ratios (HR) per mGy with 95% confidence intervals (95% CI) were calculated using conditional logistic regression adjusted for rural/nonrural habitat, education level and pre-Chernobyl cancer incidence 1980 to 1985. A total of 161,325 cancer cases in males and 144,439 in females were included. Results: The adjusted HR per mGy for all cancer sites combined was 1.027 (95% CI = 1.022, 1.031) in males and 1.011 (95% CI = 1.006, 1.017) in females. In a post hoc analysis accounting for both remaining confounding from hunter lifestyle and the pre-Chernobyl cancer incidence by county, the adjusted HR per mGy for all cancer sites combined was 1.014 (95% CI = 1.009, 1.019) in males and 1.000 (95% CI = 0.994, 1.006) in females. The post hoc analysis suggested an increased risk of cancer in the colon, pancreas, and stomach, respectively, in males, and lymphoma in females. Conclusions: Increased cancer risk estimates were found for some specific cancer sites but remaining uncontrolled confounding due to hunter lifestyle could not be ruled out.
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| 92. |
- Tondel, Martin, 1962, et al.
(författare)
-
Estimated lifetime effective dose to hunters and their families in the three most contaminated counties in Sweden after the Chernobyl nuclear power plant accident in 1986 – A pilot study
- 2017
-
Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 0265-931X .- 1879-1700. ; 177, s. 241-249
-
Tidskriftsartikel (refereegranskat)abstract
- Hunters and their families were one of the most exposed subpopulations in Sweden after the Chernobyl nuclear power plant accident in 1986. In this pilot study we used existing registries and whole-body measurements to develop algorithms to calculate lifetime effective doses and collective doses to some hunters in Sweden. Ten hunters and their family members were randomly selected from each of the three most contaminated counties in Sweden (Västernorrland, Uppsala, Gävleborg) using the register for hunting weapons from the Police Authority in 1985. Hence, this design can be regarded as a closed cohort only including hunters and their family members living in these three counties at the time of the accident. Statistics Sweden matched these individuals (n = 85) with their dwelling coordinates onto the digital map produced by the Swedish Radiation Safety Authority after aerial measurements of 137Cs (kBq m−2). Internal effective doses were estimated using aggregated transfer factors from ground deposition to in-vivo body concentration for 134Cs and 137Cs in hunters (Bq kg−1). External effective doses were also calculated on the dwelling coordinate for 134Cs, 137Cs and short-lived nuclides in these three counties. Annual effective doses for external and internal doses were then cumulated up to a life expectancy of 80 years for men and 84 years for women, respectively. The total lifetime effective doses to the members of the hunter families in this cohort were on average 8.3 mSv in Västernorrland, 4.7 mSv in Uppsala and 4.1 mSv in Gävleborg. The effective dose to men were about 40% higher than in women. In all counties the internal dose was about 75% of the total lifetime effective dose. The collective dose for all hunters with family members, in total about 44,000 individuals, in these three counties could be approximated at about 256 manSv. This study shows it is possible to use register data to develop algorithms for calculating lifetime effective dose commitments for hunters with relatively accuracy.
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| 93. |
|
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| 94. |
- Tondel, Martin, et al.
(författare)
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Increased cancer risk in male hunters compared to the general male population in Northern Sweden after the Chernobyl Nuclear Power Plant accident?
- 2020
-
Ingår i: Environmental Epidemiology. - : Ovid Technologies (Wolters Kluwer Health). - 2474-7882. ; 4:2
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Male hunters in Swedish counties with high fallout of 137Cs after the Chernobyl Nuclear Power Plant (NPP) accident have higher radiation exposure due to higher consumption of game compared with the general population. Methods: Cancer incidence in Sweden was studied in 9 counties with different 137Cs fallout after the Chernobyl NPP accident in 1986. In total, 9,267 cancer cases occurred in hunters and 138,909 cancer cases in non-hunters to 31 December 2015. Incidence rate ratios (IRR) with 95% confidence intervals (CI) were calculated using unexposed hunters, or non-hunters, as reference to study internal radiation exposure or hunter life style, respectively. Results: Directly age standardized total cancer incidence showed an increasing trend in non-hunters. For hunters, the total cancer incidence was significantly lower up to 2001 when the total cancer incidence crossed over the weaker non-hunter trend and remained higher for the following 15 years. IRRs for total cancer in hunters versus non-hunters for each county did not show any clear exposure response pattern. IRRs for hunters versus non-hunters were higher regardless of rural/non-rural status with slightly higher risk estimates for the rural settings. The IRR for hunters was 1.06 (95% CI 1.04–1.08) 1986–2015, representing an excess of 531 cancer cases in hunters. Conclusion: An increased total incidence of cancer was identified for male hunters compared with male non-hunters. No obvious association between cancer and 137Cs from the Chernobyl NPP accident could be identified, although the exposure classification was too crude to exclude such an association.
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| 95. |
|
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| 96. |
- Waldner, Lovisa, et al.
(författare)
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Experimentally determined and Monte Carlo-calculated energy dependence of NaCl pellets read by optically stimulated luminescence for photon beams in the energy range 30 keV to 1.25 MeV
- 2020
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Ingår i: Journal of Radiological Protection. - : IOP Publishing. - 0952-4746 .- 1361-6498. ; 40:4, s. 1321-1335
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Tidskriftsartikel (refereegranskat)abstract
- Ordinary salt, NaCl, has many properties suitable for dosimetry and has been suggested for both retrospective and prospective optically stimulated luminescence (OSL) dosimetry. Lately, the focus has been on NaCl that is compressed into solid pellets, as this improves both its handling and dosimetric properties. In this project, the energy dependence of NaCl pellets produced in-house was investigated for photon energies between 30 and 1.25 MeV. The NaCl pellets were first exposed to free-in-air conditions, and the estimated absorbed dose to the NaCl pellets was compared to the air kerma, K air, at the point of exposure. Second, a backscatter medium of polymethyl methacrylate (PMMA) was added, and NaCl pellets were exposed when positioned on a ISO slab phantom to relate the response in the NaCl to the personal dose equivalent, H p(10). The results show a significant energy dependence for exposure to low-energy photons with a peak over-response compared to K air and H p(10) of up to 18. Comparisons with Monte Carlo simulations show good agreement, even though the simulations cannot account for properties related to the intrinsic luminescence effects of the NaCl pellets or the readout and calibration process. The finite thickness of the NaCl pellet makes it an imperfect Bragg-Grey cavity, which complicates the behaviour of the energy dependence. The results presented here may serve as an important basis for further experimental and theoretical modelling of a build-up layer and filters in efforts to develop a passive personal dosemeter based on NaCl.
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| 97. |
- Waldner, Lovisa, et al.
(författare)
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NaCl pellets for prospective dosimetry using optically stimulated luminescence : Signal integrity and long-term versus short-term exposure
- 2020
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Ingår i: Radiation and Environmental Biophysics. - : Springer Science and Business Media LLC. - 0301-634X .- 1432-2099. ; 59:4, s. 693-702
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Tidskriftsartikel (refereegranskat)abstract
- Optically stimulated luminescence (OSL) signal properties of pellets from three types of NaCl (two household salts and one analytical grade salt) were investigated for their use in prospective dosimetry. Special attention was given to the OSL signal behaviour with time. The readout protocol was optimised in terms of preheat temperature, and the OSL signal yield of the NaCl pellet with time as well as the fading of the OSL signal with time was investigated. The effects of acute and chronic irradiations were compared. Irradiations and readout were performed using a Risø TL/OSL reader (TL/OSL-DA-15, DTU Nutech, Denmark). The optimal preheat temperature was determined to be 100 ºC, yielding OSL signals similar to a 1 h pause before OSL signal readout. There was no OSL signal fading observed as a function of time, but a decrease in the OSL signal yield of the NaCl pellets with time resulted in an apparent inverse fading when converting the OSL signal to an absorbed dose. For chronic radiation exposures of up to five weeks, the sensitivity of the NaCl pellets was found to be stable. The results of this study show that the use of NaCl pellets for prospective dosimetry is a promising, cost-effective, and accessible complement to commercially available alternatives for accurate absorbed dose determinations.
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| 98. |
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| 99. |
- Zakaria, Mohamad, et al.
(författare)
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The 2002/2003 radionuclide concentration in the marine environment at various distances from the Barseback nuclear power plant
- 2008
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Ingår i: Radioprotection. - : EDP Sciences. - 0033-8451 .- 1769-700X. ; 43:3, s. 429-438
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Tidskriftsartikel (refereegranskat)abstract
- The activity concentration of (CS)-C-137, I-131, Zn-65, Co-60, Co-58, Mn-54, and K-40 were determined in samples of brown seaweed (Fucus) and some other marine plants using low background high-resolution gamma-spectrometry. The algae were mainly sampled in the bay just north of the Barseback NPP (55.4 N, 12.6 E) in the south of Sweden to study the contamination levels in the nearest shallow waters. One aim of the study was to investigate whether the levels were high enough to expect environmental effects. Some samples were also taken at longer distances up to 130 kin from the Barseback NPP. Measurable levels of the neutron activation products Zn-65 (up to 17 Bq/kg dw), Co-60 (100-600 Bq/kg dw), Co-58 (1-160 Bq/kg dw) and Mn-54 (12-90 Bq/kg dw) were found in the algae samples within a distance of 5 kin from the plant. The decrease in activity concentration with distance from the plant could he described by a power function with an exponent ranging from 1.4 to 2.4. This was in fair agreement with the value for a true two-dimensional dispersion model. The present-day concentrations were found to be considerably lower than in earlier studies made in the late 1970s, especially for Zn-65 and Co-58. The activity concentration of gamma emitting radionuclides in Fucus vesiculosus from the bay just north of Barseback in the period 2002-2003 was dominated by (in order of decreasing concentration): natural K-40, Co-60 from the plant, Cs-137 mainly from the Chernobyl debris, Mn-54 and Co-58 from the plant. It is not likely that any effects from the very marginal absorbed dose contribution from the Barseback NPP releases can he found even in the nearest environment. The study has also shown that the eelgrass Zostera marina may be a bioindicator to use in further studies of the radiation environment in shallow water, especially for Co-60 and Mn-54.
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| 100. |
- Ören, Ünal, et al.
(författare)
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A phantom for determination of calibration coefficients and minimum detectable activities using a dual-head gammacamera for internal contamination monitoring following radiation emergency situations
- 2016
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Ingår i: Radiation Protection Dosimetry. - : Oxford University Press (OUP). - 1742-3406 .- 0144-8420. ; 169:1, s. 297-302
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to derive calibration coefficients (in terms of cps kBq-1) and minimum detectable activities, MDA, (in terms of kBq and corresponding dose rate) for the dual head gamma camera part of an SPECT/CT-instrument when used for in vivo internal contamination measurements in radiation emergency situations. A cylindrical-conical PMMA phantom with diameters in the range of 7-30 cm was developed in order to simulate different body parts and individuals of different sizes. A series of planar gamma camera investigations were conducted using an SPECT/CT modality with the collimators removed for 131I and 137Cs, radionuclides potentially associated with radiation emergencies. Energy windows of 337-391 and 490-690 keV were selected for 131I and 137Cs, respectively. The measurements show that the calibration coefficients for 137Cs range from 10 to 19 cps kBq-1 with MDAvalues in the range of 0.29-0.55 kBq for phantom diameters of 10-30 cm. The corresponding values for 131I are 12-37 cps kBq-1 with MDAvalues of 0.08-0.26 kBq. An internal dosimetry computer program was used for the estimation of minimum detectable dose rates. A thyroid uptake of 0.1 kBq 131I (representing MDA) corresponds to an effective dose rate of 0.6 μSv d-1. A 137Cs source position representing the colon with an MDA of 0.55 kBq corresponds to an effective dose rate was 1 μSv y-1. This method using a simple phantom for the determination of calibration coefficients, and MDA levels can be implemented within the emergency preparedness plans in hospitals with nuclear medicine departments. The derived data will help to quickly estimate the internal contamination of humans following radiation emergencies.
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