| 1. |
- Eriksson, M, et al.
(författare)
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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
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Ingår i: Journal of Environmental Radioactivity. - : Elsevier BV. - 1879-1700 .- 0265-931X. ; 75:3, s. 285-299
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Gäfvert, Torbjörn, et al.
(författare)
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Radionuclide fluxes at a plant manufacturing dicalcium phosphate for domestic animals
- 2001
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 54:1, s. 61-73
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Tidskriftsartikel (refereegranskat)abstract
- We have studied a phosphate rock plant which produces dicalcium phosphate (DCP), used as a source of calcium and phosphorus for domestic animals. A by-product in the manufacturing process is calcium chloride which is used in the oil industry, the food industry and as road-salt. The objectives of our study were to describe the fluxes of radionuclides from the U-238 decay series and to estimate the radiation doses to workers at the plant. The radionuclides in the phosphate rock were found to be in secular radioactive equilibrium with U-238, With an average activity concentration of 837 Bq kg(-1). Separation and concentration processes were observed at different stages in the plant. Most of the Ra-226 was found in the calcium chloride, while the major part of the U-238, about 950 Bq kg(-1), was found in the dicalcium phosphate. The annual occupational effective dose to the workers was found to be below the 1 mSv limit recommended by ICRP (1991a) for the public. This study has shown a good example of an important non-nuclear industry with a high input of natural radionuclides with several conceivable pathways to man.
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| 3. |
- Gäfvert, Torbjörn, et al.
(författare)
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Removal of radionuclides at a waterworks.
- 2002
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 63:2, s. 105-115
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Tidskriftsartikel (refereegranskat)abstract
- A waterworks with an average production rate of 1.3 m3 s(-1), providing several large cities in the province of Scania with drinking water has been studied regarding its capacity to remove several natural and anthropogenic radionuclides. The raw water is surface water from lake Bolmen which is transported through an 80 km long tunnel in the bedrock before it enters the waterworks. The method used for purification is a combination of coagulation-flocculation and filtration in sand filters. Two different purification lines are currently in use, one using Al2(SO4)3 as a coagulant and one using FeCl3. After coagulation and flocculation the precipitate is removed and the water is passed through two different sand filters (rapid filtration and slow filtration). Water samples were collected at the lake, the inlet to the waterworks, after each of the flocculation basins (Al2(SO4)3 and FeCl3), after rapid filtration and from the municipal distribution network. The samples were analysed with respect to their content of uranium, thorium, polonium, radium, plutonium and caesium. The results show a high removal capacity for uranium (about 85%), thorium (>90%), plutonium (>95%) and polonium (>90% in the coagulation-flocculation process) while caesium, strontium and radium pass through the purification process with almost unchanged activity concentrations. During transportation of the water in the tunnel it was also observed that infiltration of groundwater leads to a change in isotopic ratios and/or activity concentrations for the naturally occurring radionuclides and plutonium.
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| 4. |
- Holm, Elis
(författare)
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The Swedish Nuclear Dilemma
- 2001
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 54:2-3, s. 113-115
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Tidskriftsartikel (refereegranskat)
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| 5. |
- Isaksson, Mats, 1961, et al.
(författare)
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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
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Ingår i: Journal of Environmental Radioactivity. - 0265-931X .- 1879-1700. ; 49, s. 97-112
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Tidskriftsartikel (refereegranskat)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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| 6. |
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| 7. |
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| 8. |
- Roos, Birgitta, et al.
(författare)
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Experimental methods of determining the activity depth distribution of implanted 210Pb in glass.
- 2002
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 63:2, s. 135-151
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Tidskriftsartikel (refereegranskat)abstract
- Glass is often used in radon surveys to estimate retrospective radon concentrations, as radon progenies are embedded in the upper surface layer. Experimental methods based on etching to determine the depth distribution of recoil-implanted 210Po in glass from radon decay in air is presented. By carefully controlling chemical concentrations and exposure time during which the glass is etched, stepwise removal of the surface material was possible. Two different etching agents, diluted HF/HNO3 and NaOH were utilised, with very similar results. Experimental recoil depths of 210Po agree with theoretical calculations from the literature. The maximum implantation depth obtained using this procedure was 100 +/- 20nm.
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| 9. |
- Rääf, Christopher, et al.
(författare)
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Body burden and excretion of 137-Cs and 40K in subjects from the south of Sweden
- 2000
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 47:1, s. 83-100
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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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| 10. |
- Shaw, G., et al.
(författare)
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A cost-benefit analysis of long-term management options for forests following contamination with (CS)-C-137
- 2001
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 56:1-2, s. 185-208
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Tidskriftsartikel (refereegranskat)abstract
- This paper provides a description of a cost-benefit analysis applied to determine the cost effectiveness, or otherwise, of nine management strategies potentially applicable to forests contaminated with Cs-137. Th management strategies were considered singly and in a number of likely combinations. A management strategy was considered to be cost-effective if it resulted in a lower overall monetary detriment than was incurred if use of the contaminated forest was continued on a 'business as usual' basis. Only the banning of mushroom collection and restriction of public access proved to be cost-effective management strategies on the basis of this definition. However, even these strategies only proved cost-effective at high levels of Cs-137 contamination, at which net savings in detriment in the form of public dose were achieved. Cost-effective savings of doses to forest workers were never achieved at any of the contamination levels considered in this study. It is suggested that novel alternative uses of contaminated forests are required which could provide added value to the standing crop in return for small increases in public and worker doses. One such use might be biofuel production.
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| 11. |
- Vandenhove, H., et al.
(författare)
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Short rotation coppice for revaluation of contaminated land
- 2001
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 56:1-2, s. 157-184
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Tidskriftsartikel (refereegranskat)abstract
- When dealing with large-scale environmental contamination, as following the Chernobyl accident, changed land use such that the products of the land are radiologically acceptable and sustain an economic return from the land is a potentially sustainable remediation option. In this paper, willow short rotation coppice (SRC) is evaluated on radiological, technical and economic grounds for W. European and Belarus site conditions. Radiocaesium uptake was studied in a newly established and existing SRC. Only for light-texture soils with low soil potassium should cultivation be restricted to soils with contamination levels below 100 370 kBq m(-2) given the TFs on these soils (5 x 10(-4) and 2 x 10(-3) m(2) kg(-1)) and considering the Belarus exemption limit for firewood (740 Bq kg(-1)). In the case of high wood contamination levels ( > 1000 Bq kg(-1)). power plant personnel working in the vicinity of ash conveyers should be subjected to radiation protection measures. For appropriate soil conditions, potential SRC yields are high. In Belarus, most soils are sandy with a low water retention, for which yield estimates are too low to make production profitable without irrigation. The economic viability should be thoroughly calculated for the prevailing conditions. In W. Europe, SRC production or conversion is not profitable without price incentives. For Belarus, the profitability of SRC on the production side largely depends on crop yield and price of the delivered bio-fuel. Large-scale heat conversion systems seem the most profitable and revenue may be considerable. Electricity routes are usually unprofitable. It could be concluded that energy production from SRC is potentially a radiologically and economically sustainable land use option for contaminated agricultural land.
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| 12. |
- Vintro, LL, et al.
(författare)
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Transport of plutonium in surface and sub-surface waters from the Arctic shelf to the North Pole via the Lomonosov Ridge
- 2002
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 60:1-2, s. 73-89
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Tidskriftsartikel (refereegranskat)abstract
- New data on the levels and long-range transport of plutonium in the Arctic Ocean, recorded in the course of two expeditions to this zone in, 1994 and 1996, are discussed in this paper. Specifically, approximately 100 plutonium measurements in surface and sub-surface water sampled at 58 separate stations throughout the Kara, Laptev and East Siberian Seas, as well as along latitudinal transects across the Lomonosov Ridge, are reported and interpreted in terms of the circulation pathways responsible for the transport of this element from the North Atlantic to the Arctic Shelf and into the Arctic interior. In addition, the behaviour of plutonium in its transit through the vast Arctic shelf seas to open waters under extreme environmental conditions is discussed in terms of the partitioning of plutonium between filtered (<0.45 mum) seawater and suspended particulate, and its association with colloidal matter. Finally, limited evidence of the presence of a colloidal plutonium component in Arctic waters subject to direct riverine input is adduced.
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| 13. |
- Yiou, F, et al.
(författare)
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I-129/I-127, I-129/Cs-137 and I-129/Tc-99 in the Norwegian coastal current from 1980 to 1998
- 2002
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Ingår i: Journal of Environmental Radioactivity. - 1879-1700. ; 60:1-2, s. 61-71
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Tidskriftsartikel (refereegranskat)abstract
- Discharges of the nuclides I-129, Cs-137 and Tc-99 from the nuclear reprocessing facilities at Sellafield (UK) and La Hague (France) are very useful as oceanic tracers. On the basis of I-129/I-127, Cs-137 and Tc-99 measurements in archived seaweeds,the ratios of I-129/I-127, I-129/Cs-137 and I-129/Tc-99 have been estimated in seawater at two locations (Utsira and Kiberg) in the Norwegian Coastal Current from 1980 to 1998. These ratios, which vary up to two orders of magnitude over this period, are potentially very interesting for determining "transit times" in the Arctic and North Atlantic oceans. While the long-term trends in these ratios are quite clear, measurements in monthly and bimonthly samples show considerable structure. Further studies are required to determine the exact origin of this structure, which may be a limiting factor in the time resolution that can be obtained with these parameters.
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| 14. |
- Bergman, Björn, et al.
(författare)
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High-resolution reflection seismic imaging of the upper crust at Laxemar, southeastern Sweden
- 2002
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Ingår i: Tectonophysics. - 0040-1951 .- 1879-3266. ; 355:1-4, s. 201-213
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Tidskriftsartikel (refereegranskat)abstract
- A major cost in exploring the upper 1–2 km of crystalline crust with reflection seismics is the drilling required for explosive sources. By reducing the charge size to a minimum, shallow inexpensive shotholes can be drilled with handheld equipment. Here, we present results from a full-scale test using small charges for high-resolution seismic surveying over a nuclear waste disposal study site (not an actual site). Two 2–2.5-km-long crossing profiles were acquired in December 1999 with 10-m shot and geophone spacing in the Laxemar area, near Oskarshamn in southeastern Sweden. After standard processing, including dip moveout (DMO), several subhorizontal to moderately dipping reflections are imaged. Many of the dipping ones can be correlated to fracture zones observed in a ca. 1700-m-deep borehole where the profiles cross and/or to fracture zones mapped on the surface. The imaged fracture zones form a complex 3D pattern illustrating the necessity of having 3D control before interpreting seismic reflection data. Analyses of sonic and density logs from the borehole show that greenstones have significantly higher impedances than the more dominant granite found in the borehole (granite/greenstone reflection coefficient is +0.065). These greenstones may contribute to the reflectivity when associated with fracture zones. In some cases, where they are present as larger subhorizontal lenses, they may be the dominant source of reflectivity. A set of north-dipping (10°) reflectors at 3–3.5-km depth can be correlated to a similar set observed below the island of Ävrö about 3 km to the east.
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