uu.seUppsala University Publications
Change search
Refine search result
1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Air and Water Science.
    Alfimov, V.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics. Uppsala University, Disciplinary Domain of Science and Technology, Physics, Department of Physics and Astronomy.
    I-129 anthropogenic budget: major sources and sinks2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 3, p. 606-618Article in journal (Refereed)
    Abstract [en]

    Data are presented here on the anthropogenic 129I inventory in regions that have been strongly affected by releases from European reprocessing facilities which, to the authors’ knowledge, presently account for >90% of the global isotope source in the Earth’s surface environment. The results show that >90% of the isotope inventory occurs in marine waters with the Nordic Seas and Eurasian basin of the Arctic Ocean containing most of the 129I. Within the terrestrial environment of Europe, soils contain the largest part of the isotope inventory. However, the inventory of the terrestrial system did not provide clues on the most plausible atmospheric source of 129I to Europe, thus supply from both gaseous and marine releases is proposed. The sum of the total inventory in both the marine and terrestrial environments did not match the estimated releases. This imbalance is likely to relate to unconstrained inventory estimates for marine basins (Irish Sea, English Channel and North Sea) close to the facilities, but also to the occurrence of 129I in the biosphere, and possible overestimated releases from the nuclear reprocessing facilities. There is no doubt that the available data on 129I distribution in the environment are far from representative and further research is urgently needed to construct a comprehensive picture.

  • 2.
    Aldahan, Ala
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Englund, Edvard
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Ion Physics.
    Cato, Ingemar
    Hou, Xiaolin
    Iodine-129 enrichment in sediment of the Baltic Sea2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 3, p. 637-647Article in journal (Refereed)
    Abstract [en]

    Sediments are an excellent archive for evaluation of time-series environmental contamination of water systems. Measurements of ultra-trace radioactive species, such as 129I, provide information for both chronologic calibration and anthropogenic emissions during the nuclear era. Here data are presented on 129I and other chemical parameters from two sediment cores collected in the Baltic Sea during 1997. The sediment sections have a relatively uniform grain size (clay–mud) and cover a period of about 50 a. Distribution of 129I in the sediment strongly relates to the liquid release records from the nuclear reprocessing facilities at Sellafield and La Hague. However, syn- and post-depositional alteration of organic matter at the sediment–water interface and within the sediment column may have contributed to slightly obliterating the anthropogenic 129I signals. Indication of Chernobyl-derived 129I occurs in the sediment profile, but is apparently overridden by the overwhelming flux from the nuclear reprocessing facilities. Although the record did not cover the pre-nuclear era (before 1945) sections, the ultra sensitive 129I profile provides a potential tool for relative dating and monitoring sources of water and sediment to the region.

  • 3. Cory, Neil
    et al.
    Andrén, Cecilia
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Evolution, Limnology.
    Bishop, Kevin
    Modelling inorganic Aluminium with WHAM in environmental monitoring2007In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 22, no 6, p. 1196-1201Article in journal (Refereed)
    Abstract [en]

    Due to the varying toxicity of different Al species, information about Al concentration and speciation is important when assessing water quality. Modelling Al speciation can support operational monitoring programmes where Al speciation is not measured directly. Modelling also makes it possible to retroactively speciate older samples where laboratory fractionation was not undertaken. Organic-rich waters are a particular challenge for both laboratory analysis and models. This paper presents the modelling of Al speciation in Swedish surface waters using the Windermere Humic Acid Model (WHAM). The model was calibrated with data from operational monitoring, the Swedish national survey of lakes and rivers, and covers a broad spectrum of physical and chemical conditions. Calibration was undertaken by varying the amount of DOC active in binding Al. A sensitivity analysis identified the minimum parameters required as model input variables primarily to be total Al, organic C, pH, F, and secondly Fe, Ca and Mg. The observed and modelled Ali had no significant differences (Spearman rank, p < 0.01), however, lake samples modelled better than rivers. Samples were placed in the correct toxicological category in 89–95% of the cases. The importance of the size of the calibration data set was assessed, and reducing the calibration data set resulted in poorer correlations, but had little impact on the toxicological placement. Overall, the modelling gave satisfactory results from samples covering a broad spectrum of physical and chemical conditions. This indicates the potential value of WHAM as a tool in operational monitoring of surface waters.

  • 4. Drake, Henrik
    et al.
    Tullborg, Eva-Lena
    Annersten, Hans
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, Solid Earth Geology.
    Red-staining of the wall rock and its influence on the reducing capacity around water conducting fractures2008In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 23, no 7, p. 1898-1920Article in journal (Refereed)
    Abstract [en]

    Red-staining and alteration of wall rock is common around water conducting fractures in the Laxemar-Simpevarp area (SE Sweden), which is currently being investigated by the Swedish Nuclear Fuel and Waste Management Co. (SKB) in common with many other places. Red-staining is often interpreted as a clear sign of oxidation but relevant analyses are seldom performed. The area is dominated by Palaeoproterozoic crystalline rocks ranging in composition from quartz monzodiorite to granite. In this study wall rock samples have been compared with reference samples from within 0.1 to 1 m of the red-stained rock, in order to describe mineralogical and geochemical changes but also changes in redox conditions. A methodology for tracing changes in mineralogy, mineral and whole rock chemistry and Fe3+/Fe-tot ratio in silicates and oxides in the red-stained wall rock and the reference rock is reported. The results show that the red-stained rock adjacent to the fractures displays major changes in mineralogy, biotite, plagioclase and magnetite have been altered and chlorite, K-feldspar, albite, sericite, prehnite, epidote and hematite have been formed. The changes in chemistry are however moderate, K-enrichment, Ca-depletion and constant Fe-tot are documented. The Fe3+/Fe-tot ratio in the oxide phase is higher in the red-stained samples whereas the Fe3+/Fe-tot ratio in the silicate phase is largely similar in the wall rock and the reference samples. Because most of the Fe is hosted in the silicate phase the decrease in reducing capacity (Fe2+), if any, in the red-stained wall rock is very small and not as high as macroscopic observations might suggest. Instead, the mineralogical changes in combination with the modest oxidation and formation of minute hematite grains in porous secondary minerals in pseudomorphs after plagioclase have produced the red-staining. Increased porosity is also characteristic for the red-stained rock. Moderate alteration in the macroscopically fresh reference rock shows that the hydrothermal alteration reaches further from the fracture than the red-staining. The extent of the red-staining can therefore not be used in the same way as the extent of the alteration adjacent to a fracture. The increase in porosity in the red-stained rock may result in enhanced retention of radio-nuclides due to an increased sorptivity and diffusion close to the fracture. The hydrothermal alteration causing the red-staining is thought to have occurred at temperatures of about 250-400 degrees C, based on the secondary mineralogy. The major part of this alteration in the area is assumed to be related to fluid circulation associated with the intrusion of the Mesoproterozoic Gotemar and Uthammar granites nearby.

  • 5. Geibe, Christine E.
    et al.
    Danielsson, Rolf
    Uppsala University, Disciplinary Domain of Science and Technology, Chemistry, Department of Physical and Analytical Chemistry.
    van Hees, Patrick A. W.
    Lundström, Ulla S.
    Comparison of soil solution chemistry sampled by centrifugation, two types of suction lysimeters and zero-tension lysimeters2006In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 21, no 12, p. 2096-2111Article in journal (Refereed)
    Abstract [en]

    The choice of sampling method for soil solution is of great importance. In this paper soil solution chemistry sampled by centrifugation, two types of suction lysimeters and zero-tension lysimeters have been studied with the purpose of investigating systematic differences between them. The samples were taken at 4 depths from an acidified forest soil as well as from adjacent lime and ash treated soils. A centrifugation drainage method was compared with two types of suction lysimeters ('Rhizon' and 'Prenart') and zero-tension lysimeters. About half of the 27 variables measured showed a significant difference between the sampling methods used. Typically the centrifuged samples had lower pH (4.0 vs. 4.4), Ca (21 mu M vs. 30 mu M) and Mg (25 mu M vs. 34 mu M) concentrations and higher CI (330 mu M vs. 230 mu M) and DOC (4.4 mM vs. 3.2 mM) concentrations than the Rhizon lysimeters. Also the other lysimeters showed significant differences compared to the centrifuged samples for about half the number of analytes. Centrifuged samples had higher concentrations of all analytes except NO3 and PO4 compared to zero-tension lysimeters and also for all analytes except NO3 and Al compared to Prenart lysimeters. Among the environmental factors considered depth showed an influence to some extent, while sampling occasion had a great significant impact on the difference between the centrifugation method and the Rhizon lysimeters. Factors like individual pits or soil treatment did not show any influence on the difference between the methods.

  • 6.
    Herbert, Roger B
    et al.
    Stockholm Univ, Dept Geol & Geochem.
    Benner, S.G
    Blowes, D.W
    Solid phase iron: sulfur geochemistry of a reactive barrier for treatment of mine drainage2000In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 15, no 9, p. 1331-1343Article in journal (Refereed)
    Abstract [en]

    This paper discusses the solid phase Fe-S geochemistry of a reactive barrier at the Nickel Rim mine site (Ontario, Canada). The barrier, designed to treat groundwater contaminated by acid mine drainage, is composed of leaf and municipal compost and wood chips. This study shows that S is accumulating in the organic material as primarily acid volatile sulfides, at concentrations up to 195 mu mol S g(-1) d.w. (0.63 wt% S) in a zone of preferential flow. Pyrite and/or S-0 account for only a small fraction of the total reduced inorganic S, as oxidants are probably present at only low concentrations in the barrier system. The results of the solid phase analyses, the formation of disordered mackinawite (Fe1-xS) on piezometer tubing, and thermodynamic calculations indicate that the precipitation of poorly crystalline Fe monosulfides is the primary sink for Fe and S in the barrier. Siderite (FeCO3) formation is proposed as an additional Fe sink in areas of high Fe flux. Minor accumulations of acid-soluble, organically-bound S in the reactive barrier occur in zones of low aqueous Fe concentration. After 23 months of operation, the average rate of S accumulation at the up-gradient edge of the barrier is calculated to be 87 mu mol S g(-1) a(-1) (d.w. organic material), or 47 mol S m(-2) a(-1) in the direction of groundwater flow. Solid phase analyses from samples collected 3 and 14 months after installation indicate that the S accumulation rate declined by a factor of 3 over that time period.

  • 7.
    Tondel, Martin
    et al.
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Occupational and Environmental Medicine.
    Granath, Göran
    Wålinder, Robert
    Uppsala University, Disciplinary Domain of Medicine and Pharmacy, Faculty of Medicine, Department of Medical Sciences, Occupational and Environmental Medicine.
    137Cs activity in Sweden after the Chernobyl Nuclear Power Plant accident in relation to quaternary geology and land use2017In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 87, p. 38-43Article in journal (Refereed)
    Abstract [en]

    After the Chernobyl Nuclear Power Plant accident 137Cs was deposited in Mid-Sweden, with the highest activity in Gävle municipality. We compared aerial measurements of 137Cs on the ground over time in Gävle municipality since 1986. Maps of soil types and land use were used to analyse the decrease in activity of 137Cs. A spatial pattern was identified where the reduction of activity was greater in sand than in organic soil. For land use the reduction was greater in urban areas than in forests, with agricultural land in between. Long-term external radiation from 137Cs depends not only on the physical decay of 137Cs but also indirectly on geology, and this should be considered when calculating external radiation doses to individuals in epidemiological studies.

  • 8.
    Yi, Peng
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Chen, X. G.
    Aldahan, Ala
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Possnert, Göran
    Uppsala University, Disciplinary Domain of Science and Technology, För teknisk-naturvetenskapliga fakulteten gemensamma enheter, Tandem Laboratory.
    Hou, X. L.
    Yu, Z. B.
    Xiong, D. H.
    Wang, Biao
    Uppsala University, Disciplinary Domain of Science and Technology, Biology, Department of Ecology and Genetics, Population and Conservation Biology.
    Circulation of water masses in the Baltic Proper revealed through iodine isotopes2013In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 36, p. 118-124Article in journal (Refereed)
    Abstract [en]

    Tracer technology has been used to understand water circulation in marine systems where the tracer dose is commonly injected into the marine waters through controlled experiments, accidental releases or waste discharges. Anthropogenic discharges of I-129 have been used to trace water circulation in the Arctic and North Atlantic Ocean. Here, I-129, together with I-127, is utilized as a tracer of water pathways and circulation in the Baltic Sea through collection of seawater depth profiles. The results indicate the presence of I-129 signatures which are distinct for each water mass and provide evidence for: (1) inflow water masses through the Drogden Sill that may reach as far as the SW of the Arkona Sea, (2) a portion of North Atlantic water in the bottom of Arkona basin, (3) cyclonic upwelling which breaks through the halocline in a pattern similar to the Baltic haline conveyor belt and (4) more influx of fresher water from the Gulf of Finland and Bothnian Sea in August relative to April. These findings provide advances in labeling and understanding water pathways in the Baltic Sea.

  • 9.
    Zdanowicz, Christian
    et al.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Zheng, Jiancheng
    Geol Survey Canada, Nat Resources Canada, 601 Booth St, Ottawa, ON K1A 0E8, Canada.; Univ Ottawa, Dept Earth & Environm Sci, FSS Hall,120 Univ, Ottawa, ON K1N 6N5, Canada.
    Klimenko, Elena
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Outridge, Peter
    Geol Survey Canada, Nat Resources Canada, 601 Booth St, Ottawa, ON K1A 0E8, Canada.; Univ Manitoba, Ctr Earth Observat Sci, 535 Wallace Bldg, Winnipeg, MB R3T 2N2, Canada .
    Mercury and other trace metals in the seasonal snowpack across the subarctic taiga-tundra ecotone, Northwest Territories, Canada2017In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 82, p. 63-78Article in journal (Refereed)
    Abstract [en]

    In Canada's Northwest Territories, mining for base metals and diamonds are vital economic activitieswhich carry risks of adverse environmental impacts. To gather baseline geochemical data against which the impact of future mining activities may be measured, a survey of trace metal concentrations in snow was carried out in 2012 along a 285-km stretch of winter mining road crossing the taiga-tundra ecotone between latitudes 62.8 and 65.5 degrees N. The distribution of 17 elements, including mercury (Hg), was measured and mapped. Results indicate that road traffic along the winter road has only a modest impact on the metal content of the nearby tundra-taiga snowpack, and that this impact is largely due to the mobilization of soil dust and associated elements. However, some enrichment of As, Pb, Sr and Zn in snow was detected near former gold mine sites, likely reflecting the windborne dispersion of contam-inated soils. The Hg concentrations in snow across the study area were generally low (<=3.01 ng L^-1), anddid not covary with any  other metals, which suggests atmospheric deposition from distant/diffuse sources. An analysis of air back-trajectories pointed to the most likely distant (>10^3 km) anthropogenic source regions being eastern Asia or Russia. Using Hg data from the present survey and another source, in combination with gridded maps of snowpack water equivalent, we calculated the potential flux of atmospherically-derived Hg that could be released by spring snowmelt into the Mackenzie River to be in the order of ~195 to 404 kg a^-1, which may represent a substantial fraction of the estimated total Hg discharge to the Beaufort Sea.

1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf