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  • 351.
    Drugge, Lisbeth
    Luleå tekniska universitet.
    Geochemistry of the Lule River, northern Sweden, before and after regulation2003Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Lule River is the largest and most important river for hydropower production in Sweden. This river, situated in the northern part of the country, has been regulated since the beginning of the 20th century and is heavily regulated with 15 power stations. The major aim of this study is to quantify the transport of nutrients and other elements in a reservoir, Stora Lulevatten, since knowledge about processes in upstream reservoirs is limited. Monthly sampling of the filtered (<0.22m) phase of river water was performed at the Porjus and Vietas power stations over a period of 15 months. To quantify the effects of river regulation, a geochemical mass balance study was performed. The results show retention of S, K, Si, NO3-N, Fe, PO4-P, Al, Mn and DOC in the reservoir. The study indicates retention levels of 34-43% for Si, Al, Mn, DOC, PO4-P, NO3-N, and for Fe, as much as 68%. A model comparing pre-regulation transport of elements at Porjus power station with present-day transport is presented. The results agree well with the retention of S, DOC, Fe Si, Mn and Al in the reservoir, and thus decreased transport after regulation. One reason for the changed transport is the changed discharge pattern after regulation. Three sediment cores were sampled in the reservoir, and analysed in details for main elements, P and N, and diatom frustules were counted in the sediments. A significantly higher Si/Al ratio could be observed in all three cores after regulation, which correlates with an increased concentration of diatoms in the sediment. The annual retention of non-detrital Si in the sediments as calculated from sediment geochemistry (2138 tonnes Sind/year) is in relatively good agreement with the retention obtained from the mass balance study (3320 tonnes Si/year). A comparison of the background and present-day accumulation of non-detrital Si suggests that the Si retention has increased by 698 tonnes/year after regulation of the Lule River. This increase may be an effect of an increased diatom production in Stora Lulevatten appearing after the construction of the reservoir. Seasonal variations in the geochemical constituents in the regulated Lule River have been studied during an entire year cycle (May 2000 to June 2001) at the Boden power station, near the mouth of the river. Comparing the Si retention in the reservoir with the total transport of Si at Boden, the increased deposition of 698 tonnes Si/year corresponds to a reduction in the Si transport to the Gulf of Bothnia by 2%. The geochemistry of the regulated Lule River is compared with a pristine river, the Kalix River, for which data from a previous study at Luleå University of Technology are available. The results from this comparison show that the transport of Fe (and probably also of P) was found to be clearly decreased due to regulation. The decreased transport of Fe agrees well with the mass balance study, decreased transport after regulation at Porjus and retention of Fe and P in the sediments in Stora Lulevatten. Stora Lulevatten acts as a sink for Fe, Si and P. Considering that Stora Lulevatten is small compared to upstream reservoirs, the total retention is probably larger than that observed in Stora Lulevatten. A result of changed discharge pattern after regulation is that nutrients and other elements reach the Gulf of Bothnia in changed amounts and during different seasons than what would have been the case for an unregulated river.

  • 352.
    Du, Andao
    et al.
    National Research Centre of Geoanalysis, 26 Baiwanzhun Dajie, Beijing.
    Wu, Shuqi
    National Research Centre of Geoanalysis, 26 Baiwanzhun Dajie, Beijing.
    Sun, Dezhong
    National Research Centre of Geoanalysis, 26 Baiwanzhun Dajie, Beijing.
    Wang, Shuxian
    National Research Centre of Geoanalysis, 26 Baiwanzhun Dajie, Beijing.
    Markey, Richard
    AIRIE Group, Department of Earth Resources, Colorado Slate University.
    Stain, Holly
    AIRIE Group, Department of Earth Resources, Colorado Slate University.
    Morgan, John
    AIRIE Group, Department of Earth Resources, Colorado Slate University.
    Malinovskiy, Dmitry
    Preparation and certification of Re-Os dating reference materials: molybdenites HLP and JDC2004In: Geostandards and Geoanalytical Research, ISSN 1639-4488, E-ISSN 1751-908X, Vol. 28, no 1, p. 41-52Article in journal (Refereed)
    Abstract [en]

    Two Re-Os dating reference material molybdenites were prepared. Molybdenite JDC and molybdenite HLP are from a carbonate vein-type molybdenum-(lead)-uranium deposit in the Jinduicheng-Huanglongpu area of Shaanxi province, China. The samples proved to be homogeneous, based on the coefficient of variation of analytical results and an analysis of variance test. The sampling weight was 0.1 g for JDC and 0.025 g for HLP. An isotope dilution method was used for the determination of Re and Os. Sample decomposition and pre- concentration of Re and Os prior to measurement were accomplished using a variety of methods: acid digestion, alkali fusion, ion exchange and solvent extraction. Negative thermal ionisation mass spectrometry and inductively coupled plasma-mass spectrometry were used for the determination of Re and 187Os concentration and isotope ratios. The certified values include the contents of Re and Os and the model ages. For HLP, the Re content was 283.8 ± 6.2 µg g-1, 187Os was 659 ± 14 ng g-1 and the Re-Os model age was 221.4 ± 5.6 Ma. For JDC, the Re content was 17.39 ± 0.32 µg g-1, 187Os was 25.46 ± 0.60 ng g-1 and the Re-Os model age was 139.6 ± 3.8 Ma. Uncertainties for both certified reference materials are stated at the 95% level of confidence. Three laboratories (from three countries: P.R. China, USA, Sweden) joined in the certification programme. These certified reference materials are primarily useful for Re-Os dating of molybdenite, sulfides, black shale, etc. .

  • 353.
    Dubois, Isabelle E.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Specific surface area of some minerals commonly found in granite2011Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    The specific surface area, determined by the BET method, is a parameter often used to scale results of mineral studies of surface reactions in terms of rate and capacity to the field scale. Such extrapolations of results from small-scale laboratory experiments to the field-scale are important within many environmental applications. An example of this is for the prediction of radionuclide retention in the bedrock surrounding a deep repository for radioactive waste, following failure of the engineered barriers, where radionuclides may sorb onto minerals constituting the geological environment.

    As a first step, the approach used in this work is to study the relationship between specific surface area and the particle size (0.075-8 mm) and to approach the field scale via measurements on large, centimetre-sized pieces, for seven natural minerals commonly found in granite: apatite, biotite, chlorite, K-feldspar, hornblende, labradorite and magnetite. The underlying assumption is that sorption of radionuclides can be related to specific surface area of a particular mineral in a continuation of this project.The results show that the phyllosilicates biotite and chlorite have a specific surface area that is about 10 times larger than the other minerals. Over the range of particle size fractions studied, the specific surface area varies between 0.1 and 1.2 m2g-1 for biotite and chlorite. The other studied minerals have specific surface areas varying between 0.01 m2g-1 for the largest fraction and up to 0.06 - 0.12 m2g-1 for the smallest. Results show linear relationships between the specific surface area and the inverse of the particle size for all studied minerals for small particle sizes, as expected. For some minerals, however, the data seemingly can be divided in two linear trends, where a change in internal surface area, surface roughness and/or particle geometry as the particle size decreases may explain this behaviour.

    Interestingly, for larger particles, there is a deviation from the linearity observed for small particles. Tentatively, this behaviour is attributed to a disturbed zone, created by the mechanical treatment of the material during particle size reduction, extending throughout small particles, but not altering an undisturbed core of the larger particles. In agreement with this, measurements on large pieces show a surface area 5 to 150 times lower than expected from the linear trends observed for the crushed material, implying an overestimation of the surface area and possibly also of the sorption capacities of the rock material from simple extrapolations of experimental results employing finely crushed material to the field situation.

  • 354.
    Dubois, Isablle E.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology (moved 20130630). Chalmers University of Technology, Gothenburg, Sweden.
    Holgersson, S.
    Allard, S.
    Malmström, Maria
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology (moved 20130630).
    Correlation between particle size and surface area for chlorite and K-feldspar2010In: Water-Rock Interaction - Proceedings of the 13th International Conference on Water-Rock Interaction, WRI-13 / [ed] P. Birkle, I.S. Torres-Alvorado, 2010, p. 717-720Conference paper (Refereed)
    Abstract [en]

    The specific surface area as determined by BET analysis is often used for scaling mineral surface reaction capacities and rates between particles of different sizes as found in nature. Generally, an inverse proportionality between BET area and particle size is assumed, based on geometry. However, macroscopic laboratory studies of mineral surface reactions generally employ crushed material that may have been mechanically disturbed, potentially leading to an artificial increase in the specific surface area, and a change in the apparent surface reactivity. In this study, we determine the BET area for natural K-feldspar and chlorite samples from Sweden as function of particle size in a first step towards relating the surface reactivity for these minerals to grain size.

  • 355.
    Dubois, Isablle E.
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology (moved 20130630).
    Holgersson, S.
    Allard, S.
    Malmström, Maria
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology (moved 20130630).
    Dependency of BET surface area on particle siz for some granitic minerals2011In: Proc. radiochem. acta, Vol. 1, p. 75-82Article in journal (Refereed)
    Abstract [en]

    In order to assess the geochemical retention properties of rocks, which will be the final barrier for radionuclide transport to the biosphere in the case of a failed deep underground repository for spent nuclear fuel, radionuclide sorption experiments are usually made with crushed material. This raises the issue of extrapolating results obtained from laboratory experiments to the field scale. As sorption is generally related to the surface area of the geological material, it is then important to consider the dependency of the specific surface area on the particle size. In this work, BET surface area determinations of samples of different particle sizes are conducted on two minerals commonly found in granite: labradorite and magnetite. The results show a linearre lationship between BET surface area and the inverse of the particle size, up to a certain particle size. Furthermore, results also show that the specific surface area for intact, larger pieces is much smaller than the one predicted by a linear extrapolation of results on crushed material. Therefore, extrapolation of BET area for fine particles to the field situation will lead to an overestimation of the surface area and thereby also the radionuclide sorption, if sorption coefficients are extrapolated as well. Also of importance is that these results show that sorption experiments on crushed material may dominantly reflect properties of new surface, created during the mechanically treatment of the samples.

  • 356. Duffy, Brendan
    et al.
    Quigley, Mark
    Harris, Ron
    Ring, Uwe
    Stockholm University, Faculty of Science, Department of Geological Sciences. University of Canterbury.
    Arc-parallel extrusion of the Timor sector of the Banda arc-continent collision2013In: Tectonics, ISSN 0278-7407, E-ISSN 1944-9194, Vol. 32, no 3, p. 641-660Article in journal (Refereed)
    Abstract [en]

    Structural studies of synorogenic basins in Timor using field and remote sensing techniques provide new structural and geomorphic evidence for syn-collisional extension in the converging plate boundary zone between the Australian Plate and Banda Arc. Fault mapping and kinematic analysis at scales ranging from outcrop (<1m(2)) to the dimensions of the active orogen in East Timor (similar to 100km(2)) identify a predominance of NW-SE oriented dextral-normal faults and NE-SW oriented sinistral-normal faults that collectively bound large (5-20km(2)) bedrock massifs throughout the island. These fault systems intersect at non-Andersonian conjugate angles of approximately 120 degrees and accommodate an estimated 20km of NE-directed extension across the Timor orogen based on reconstructions of fault-dismembered massifs. Major orogen-parallel ENE-oriented faults on the northern and southern sides of Timor exhibit normal-sinistral and normal-dextral kinematics, respectively. The overall pattern of deformation is one of lateral crustal extrusion sub-parallel to the Banda Arc. Stratigraphic relationships suggest that extrusion began prior to 5.5Ma, before pronounced rapid uplift of the orogen. We link this to progressive coupling of the fore-arc to an underthrust plateau on the Australian Plate and subduction of its ocean crust. Our results enable us to track the structural evolution of the upper crust during dramatic plate-boundary reorganizations accompanying the transition from subduction to collision. The deformation structures that we document suggest that both upper and lower plate deformation during incipient island arc-continent collision was largely controlled by the geometry and topography of the lower plate.

  • 357.
    Dumas, Helene
    Luleå tekniska universitet.
    Litho-facies of the metasedimentary formations in the central part of the Skellefteå district1986Report (Other academic)
  • 358.
    Ebenå, Gustav
    et al.
    Linköping University, Department of Biology.
    Hagberg, Jessika
    Örebro University, MTM, Department of Natural Sciences, Örebro.
    Carlsson, Erik
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Origin and distribution of low molecular weight organic acids and bacteria in a depth profile of a soil covered tailings impoundment in northern Sweden2007In: Journal of Geochemical Exploration, ISSN 0375-6742, E-ISSN 1879-1689, Vol. 92, no 2-3, p. 186-195Article in journal (Refereed)
    Abstract [en]

    The tailings at Kristineberg, northern Sweden, have a very low content of organic carbon, a feature common with many sulfidic tailing impoundments. Three different experiments were set-up to assess the role of carbon dioxide in a depth profile. Firstly, pore gas was collected in vials from ground water pipes at various points in the profile of a dry covered tailings impoundment and analyzed in the laboratory for CO2, O2, N2, H2, and CH4 contents. Secondly, pore water was extracted from tension lysimeters at various depths. This water was analyzed for numbers of bacteria (iron-oxidizing and sulfur-oxidizing, both by MPN), and low molecular weight organic acids. Thirdly, Acidithiobacillus ferrooxidans (Strain DSMZ No 1927) was grown on a mixture of irradiated tailings and sterile water. The amount of organic acids produced was monitored.The largest bacterial count of iron-oxidizing bacteria, 4.7 × 105/g tailings, was at the oxidation front, while the heterotrophic sulfur-oxidizing bacteria were mainly found in the unsaturated, oxidized zone, 2.65 × 104/g tailings. The oxidation front was also the location where the largest amount of organic acids was found in the field study (formate 0.83 mg/l and acetate 0.51 mg/l). The acetic acid found coincides with the highest count of iron-oxidizing bacteria.The intrusion of O2 and CO2 at the studied location is enough for microbiological activity, although the overall effect on AMD production is not addressed.The results from laboratory incubations indicate that the microbial community produces organic carbon with CO2 as the sole carbon source, up to 1.35 mg/l after 16 weeks measured as TOC.To conclude, we suggest that knowledge of the intrusion of both CO2 and O2 is vital for a full understanding of the microbial ecology, and thus the weathering processes, in a dry covered tailings impoundment. Hence, the CO2 produced in the till cover and entering the tailings ecosystem is crucial to the function of the ecosystem.

  • 359.
    Ecke, Frauke
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Christensen, Pernilla
    Rentz, Ralf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Hörnfeldt, Birger
    Do landscape properties matter for densities of the grey-sided vole?: a comparison among managed and pristine forest landscapes2007In: 5. European Congress of Mammology, 2007, Vol. 2, p. 467-467Conference paper (Other academic)
  • 360.
    Ecke, Frauke
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Christensen, Pernilla
    Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, Umeå.
    Rentz, Ralf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Nilsson, Mats
    Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, Umeå.
    Sandström, Per
    Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, Umeå.
    Hörnfeldt, Birger
    Department of Forest Resource Management and Geomatics, Swedish University of Agricultural Sciences, Umeå.
    Landscape structure and the long-term decline of cyclic grey-sided voles in Fennoscandia2010In: Landscape Ecology, ISSN 0921-2973, E-ISSN 1572-9761, Vol. 25, no 4, p. 551-560Article in journal (Refereed)
    Abstract [en]

    Changes in forest landscape structure have been suggested as a likely contributing factor behind the long-term decline in the numbers of cyclic grey-sided voles (Clethrionomys rufocanus) in northern Fennoscandian lowland regions in contrast to mountain regions due to the absence of forest management in the mountains. This study, for the first time, formally explored landscape structure in 29 lowland (LF) and 14 mountain forest (MF) landscapes (each 2.5 × 2.5 km) in northern Sweden, and related the results to the cumulated spring trapping index of the grey-sided vole in 2002-2006. The grey-sided vole showed striking contrasts in dynamics close in space and time. The MF landscapes were characterized by larger patches and less fragmentation of preferred forest types. The grey-sided vole was trapped in all of 14 analyzed MF landscapes but only in three out of 29 of the LF landscapes. MF and LF landscapes with grey-sided vole occurrence were characterized by similar focal forest patch size (mean 357 ha, minimum 82 ha and mean 360 ha, minimum 79 ha, respectively). In contrast, these MF compared to the LF landscapes were characterized by larger patches of preferred forest types and less fragmented preferred forest types and by a lower proportion of clear-cut areas. The present results suggest that landscape structure is important for the abundance of grey-sided voles in both regions. However, in the mountains the change from more or less seasonal dynamics to high-amplitude cycles between the mid 1990s and 2000s cannot be explained by changes in landscape structure.

  • 361.
    Ecke, Frauke
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Engström, Emma
    Rentz, Ralf
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Husson, Eva
    Sediment and water interactions with macrophyte element concentrations and community structure2009Conference paper (Other academic)
    Abstract [en]

    Littoral interactions among sediment, water and macrophytes are poorly understood. In particular there is a gap in knowledge concerning the importance of macrophytes as sinks and sources of trace elements. Such knowledge is however central for, amongst others, explaining potential mechanisms behind the community structure of macrophytes and for the development of macrophyte-based indicator values. We studied the interactions between the three matrices (sediment, water and macrophytes) at 19 sampling sites in Storträsket, a 1.7 km2 boreal lake at the land uplift coast of Northern Sweden in summer 2008. The catchment of Storträsket was dominated  by coniferous forest of mainly the dwarf-shrub type and open wet mires. The upper sediment layers (0-6 cm) were dominated by fine detritus. Fine detritus dominated also the lower layers (>6 cm but ≤10 cm) at all but four of the studied localities where fine sediments (particle diameter <0.2 mm) dominated. Sediment and water element concentrations were related to element concentrations in the dominating macrophyte species, viz. Nuphar lutea (roots and leaves), Potamogeton natans (leaves) and Sparganium angustifolium (leaves) and to chlorophyll concentrations using uni- and multivariate statistics. We studied 27 major and trace elements. Estimations of abundance and biomass of N. lutea in eight bays was based on the evaluation of high resolution (2 cm) aerial photographs. The total biomass of N. lutea and standardized biomass (biomass per unit of area) differed significantly among bays. Also concentrations in all matrices as well as in chlorophyll showed significant spatial variation in the lake. N. lutea showed for several elements significant partitioning of elements between roots and leaves (e.g. Ca, K, Na, Fe, Pb, Zn). Correlations between element concentrations in sediment/water and in macrophytes were in general weak but significant for amongst others Si in water and leaves of P. natans and Co, Cu and Fe in water and roots of N. lutea. Interpreting correlations of elements between the sediment and macrophytes might in our study be impeded by potential incorporation of lithogenic material in extracellular macrophyte tissue. Our study identified especially N. lutea as a major sink (during vegetation period) and source (during autumn and winter) of several major and trace elements. Interactions between the matrices, chlorophyll concentrations and macrophyte community structure are further discussed as well as the implications of our results for the development of macrophyte-based indicator values.

  • 362.
    Egli, M.
    et al.
    Department of Geography, University of Zurich, Switzerland.
    Filip, D.
    Department of Geography, University of Zurich, Switzerland.
    Mavris, C.
    Department of Geography, University of Zurich, Switzerland.
    Fischer, B.
    Department of Geography, University of Zurich, Switzerland.
    Götze, J.
    TU Bergakademie Freiberg, Institute of Mineralogy, Freiberg, Germany.
    Raimondi, S.
    Dipartimento Sistemi Agro-Ambientali, Università degli Studi di Palermo, Palermo, Italy.
    Seibert, J.
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Rapid transformation of inorganic to organic and plant-available phosphorous in soils of a glacier forefield2012In: Geoderma, Vol. 189-190, p. 215-226Article in journal (Refereed)
    Abstract [en]

    Chemical weathering of rocks or sediments is extremely important for the generation of soils, for the evolution of landscape, and as a main source of inorganic nutrients for plant growth and therefore for life. Temporal trends in weathering mechanisms, plant succession and nutrients availability in cold environments can be successfully studied in soil chronosequences along a glacier forefield. In the present paper, this was carried out in the pro-glacial area of Morteratsch. Different forms of phosphorous in the soil, stream and spring water chemistry were investigated. Apatite constitutes the main source of P, but it occurs only as a minor accessory mineral phase in the granitic/gneiss parent material. The identification of apatite was performed using SEM-EDX and cathodoluminescence. Water chemistry data indicated some calcite dissolution at the earliest phase of exposure, pyrite and - on older surfaces increasingly - feldspar weathering. Apatite also seemed to contribute to Ca which is leached from the soils. The concentrations of dissolved P in the stream and spring waters were, however, extremely low (only a few μg P/l). In the topsoil, the total stocks of P showed a slight decrease with time. Losses were rather difficult to detect even though the water fluxes through the soils and discharges are relatively high. Soil organic P is almost identical to the EDTA-extractable fraction. In an 11.5. ky-old soil outside the glacier forefield the concentration and proportions of organic P, EDTA-extractable P and inorganic P forms did not differ that much from the oldest soils (max. 150. years) of the glacier forefield. In the bulk soil, about 78% of total P was transformed into an organic form (40% already after 150. years) and, in the fine earth, about 81% (40-70% after about 150. years of soil evolution). Thus the P transformation reactions are shown to be very rapid, occur predominantly in the early phase of soil formation, and could be best described by an exponential decay model. © 2012 Elsevier B.V.

  • 363.
    Ehlin, Per-Olov
    Luleå tekniska universitet.
    Birch leaf compositions above different types of bedrock in glaciated areas1985In: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 107, no 3, p. 223-231Article in journal (Refereed)
    Abstract [en]

    Birch leaves (Betula alba) as well as Ao, A2, B2 and C soils can rarely indicate the underlying rock type. Plants may show only anomalous concentrations of characteristic elements such as Ca above limestone and Cr or Ni above gabbro. If the plant compositions are used to distinguish types of basement rock, they could differentiate slightly between limestone and quartzite, limestone and granite, and porphyrite and granite, using their Ti, Al and Cu data, respectively. B2 soil analyses could differentiate between limestone and silicate rocks in the basement, using Ca or Mg data. Plants have also a limited capacity to reflect the underlying soil; only Fe data are highly correlated with those of C and Ao soil. Compositional correlations between plants and soil or rock are strongest in wetlands

  • 364.
    Ehlin, Per-Olov
    Luleå tekniska universitet.
    Seasonal variations in metal contents of birch1982In: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 104, no 1, p. 63-67Article in journal (Refereed)
    Abstract [en]

    A two year study of the metal content of birch leaves shows that most of the major elements increase in content during the growth season, whereas Cu and Ni decrease during its beginning. All trace elements have rather constant contents after the beginning of July. Ground water changes seem to explain the differences in major element contents between samples taken from 1977 and 1978. Physiological and leaf weight changes could explain the major variations during the growth season and the physiologically influenced increases are well eliminated by normalizations. Only the 1977 Mn increase is not eliminated, probably because of unusual ground water content. The best normalizations found are those with respect to Fe + Al + Zn, Ba + Sr and Al + Ti. Irregular variations in metal contents are hardly caused by occasional weather changes; probably they are caused by occasional ground water variations.

  • 365.
    ehlin, Per-Olov
    Luleå tekniska universitet.
    Uptake of Ni and Cu by birch trees in a mineralized area in northern Sweden1983In: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 105, no 1, p. 17-21Article in journal (Refereed)
    Abstract [en]

    Young leaves and twigs of birch have been analysed along a profile across a narrow pyrrhotite-pentlandite mineralization in gabbro. A Ni-Cu anomaly is apparent in the plants and is still more distinct after normalization with respect to Ba + Sr. Leaf samples generally have a stronger contrast than twigs

  • 366.
    Ekblom, Sanna
    et al.
    Örebro University, Örebro, Sweden.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Treatment of Historical Mining Waste using different Incineration Ashes2017In: Mine Water & Circular Economy / [ed] Wolkersdorfer, C., Sartz, L., Sillanpää, M. and Häkkinen, A, Lappeenranta, Finland: Lappeenranta University of Technology , 2017, Vol. II, p. 1125-1132Conference paper (Refereed)
    Abstract [en]

    ARD from historical mining sites in Sweden is a major source for trace elements to surface waters. In order to be able to treat a large portion of these sites cost effective reclamation methods is necessary. Incineration ashes were used in leaching tests to study their effect on a highly weathered mining waste in order to neutralize acidity and immobilize trace elements. This study shows that ashes can be used to increase pH and decrease trace element mobility from oxidized mining waste. Increased leaching of Cl, Mo and Sb, however, needs to be considered for waste fuel ashes before use.

  • 367.
    Ekeberg, Jonas
    et al.
    Umeå University, Faculty of Science and Technology, Department of Physics. ABB Schweiz AG, Corporate Research, CH-5405 Baden-Dättwil, Switzerland.
    Stasiewicz, Kristof
    Swedish Institute of Space Physics, P.O. Box 537, SE-751 21 Uppsala, Sweden.
    Wannberg, Gudmund
    Swedish Institute of Space Physics, P.O. Box 812, SE-981 28 Kiruna, Sweden.
    Sergienko, Tima
    Swedish Institute of Space Physics, P.O. Box 812, SE-981 28 Kiruna, Sweden.
    Eliasson, Lars
    Swedish Institute of Space Physics, P.O. Box 812, SE-981 28 Kiruna, Sweden.
    Incoherent scatter ion line enhancements and auroral arc-induced Kelvin-Helmholtz turbulence2015In: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 122, p. 119-128Article in journal (Refereed)
    Abstract [en]

    We present two cases of incoherent-scatter ion line enhancements in conjunction with auroral arcs drifting through the radar beam. The up- and downshifted ion line shoulders as well as the spectral region between them are enhanced equally and simultaneously. The power enhancements are one order of magnitude above the thermal level and are concentrated in less than 15 km wide altitude ranges at the ionospheric F region peak. The auroral arc passages are preceded by significantly enhanced ion temperatures in the E region, which are shown to generate high velocity shears. We use a Hall MHD model of velocity shears perpendicular to the geomagnetic field and show that a Kelvin-Helmholtz instability will grow for the two presented cases. We assess the possibility that the subsequently generated low frequency turbulence can explain the observed spectrally uniform ion line power enhancements.

  • 368. El Albani, Abderrazak
    et al.
    Bengtson, Stefan
    Canfield, Donald E.
    Bekker, Andrey
    Macchiarelli, Roberto
    Mazurier, Arnaud
    Hammarlund, Emma U.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Boulvais, Philippe
    Dupuy, Jean-Jacques
    Fontaine, Claude
    Fuersich, Franz T.
    Gauthier-Lafaye, Francois
    Janvier, Philippe
    Javaux, Emmanuelle
    Ossa, Frantz Ossa
    Pierson-Wickmann, Anne-Catherine
    Riboulleau, Armelle
    Sardini, Paul
    Vachard, Daniel
    Whitehouse, Martin
    Meunier, Alain
    Large colonial organisms with coordinated growth in oxygenated environments 2.1 Gyr ago2010In: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 466, no 7302, p. 100-104Article in journal (Refereed)
    Abstract [en]

    The evidence for macroscopic life during the Palaeoproterozoic era (2.5-1.6 Gyr ago) is controversial(1-5). Except for the nearly 2-Gyr-old coil-shaped fossil Grypania spiralis(6,7), which may have been eukaryotic, evidence for morphological and taxonomic bio-diversification of macroorganisms only occurs towards the beginning of the Mesoproterozoic era (1.6-1.0 Gyr)(8). Here we report the discovery of centimetre-sized structures from the 2.1-Gyr-old black shales of the Palaeoproterozoic Francevillian B Formation in Gabon, which we interpret as highly organized and spatially discrete populations of colonial organisms. The structures are up to 12 cm in size and have characteristic shapes, with a simple but distinct ground pattern of flexible sheets and, usually, a permeating radial fabric. Geochemical analyses suggest that the sediments were deposited under an oxygenated water column. Carbon and sulphur isotopic data indicate that the structures were distinct biogenic objects, fossilized by pyritization early in the formation of the rock. The growth patterns deduced from the fossil morphologies suggest that the organisms showed cell-to-cell signalling and coordinated responses, as is commonly associated with multicellular organization(9). The Gabon fossils, occurring after the 2.45-2.32-Gyr increase in atmospheric oxygen concentration(10), may be seen as ancient representatives of multicellular life, which expanded so rapidly 1.5 Gyr later, in the Cambrian explosion.

  • 369.
    Elhami, Ehsan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ask, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Erlström, Mikael
    Geological Survey of Sweden.
    Mattsson, Hans
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Physical Properties of Core Samples from the Swedish Part of the Southern Baltic Sea: Implications for CO2 Storage2016In: Energy Procedia, ISSN 1876-6102, E-ISSN 1876-6102, Vol. 97, p. 356-363Article in journal (Refereed)
    Abstract [en]

    This paper presents the results from a series of physical measurements conducted on core samples from the Swedish part of the southern Baltic Sea. The samples consist of 16 Cambrian sandstone samples (potential reservoir rock) and 9 Ordovician limestone samples (potential caprock). The two rock types reveal contrasting properties; axial P-wave velocity and density for the sandstone samples are 3.14±0.95km/s and 2.26±0.12 gr/cm3, respectively while for the limestone samples they are 6.09±0.22km/s and 2.58±0.08 gr/cm3, respectively. The scatter of the evaluated properties indicates aleatory variability and epistemic uncertainty in the properties which can be better addressed by further tests on more samples.

  • 370.
    Elhami, Ehsan
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ask, Maria
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Mattsson, Hans
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Mining and Geotechnical Engineering.
    Physical- and geomechanical properties of a drill core sample from 1.6 km depth at the Heletz site in Israel: Some implications for reservoir rock and CO2 storage2016In: International Journal of Greenhouse Gas Control, ISSN 1750-5836, E-ISSN 1878-0148, Vol. 48, no 1, p. 84-93Article in journal (Refereed)
    Abstract [en]

    We have measured physical- and geomechanical properties of a core sample that was collected from 1.6 km depth at the Heletz site in Israel, within reservoir rock, layer A. The core sample is composed of poorly consolidated sandstone, with several layers of coarser grain sizes. Average bulk density and porosity are 1.93 ± 0.11 g/cm3 and 36 ± 5%, respectively.Both nondestructive and destructive tests have been made on the core sample and its subsamples, including CT-scanning, oedometer tests, drained direct shear tests, as well as measurements of index properties, X-ray fluorescence and X-ray diffraction. These tests provide an initial evaluation of the properties of the reservoir rock, but are far from capturing epistemic variability of the reservoir rock. The results support the macroscopic observation, that the sample is poorly consolidated compared to its depth of deposition. The effective pre-consolidation pressure is less than 0.2 MPa and the maximum peak shear strength obtained is less than 1 MPa (normal stress = 1 MPa). In comparison, effective vertical stress from weight of the overlying rocks is estimated to 14 MPa using the average bulk density of the core. All measurements suggest that our reservoir rock sample is extremely weak with respect to its depth of deposition.

  • 371.
    Ellmann, Artu
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    Two deterministic and three stochastic modifications of Stokes’s formula: A case study for the Baltic countries2005In: Journal of Geodesy, ISSN 0949-7714, E-ISSN 1432-1394, Vol. 79, no 1-3, p. 11-23Article in journal (Refereed)
    Abstract [en]

    In regional gravimetric geoid determination, it is customary to use the modified Stokes formula that combines local terrestrial data with a global geopotential model. This study compares two deterministic and three stochastic modification methods for computing a regional geoid over the Baltic countries. The final selection of the best modification method is made by means of two accuracy estimates: the expected global mean square error of the geoid estimator, and the statistics of the post-fit residuals between the computed geoid models and precise GPS-levelling data. Numerical results show that the modification methods tested do not provide substantially different results, although the stochastic approaches appear formally better in the selected study area. The 2.8-5.3 cm (RMS) post-fit residuals to the GPS-levelling points indicate the suitability of the new geoid model for many practical applications. Moreover, the numerical comparisons reveal a one-dimensional offset between the regional vertical datum and the geoid models based upon the new GRACE-only geopotential model GGM01s. This gives an impression of a greater reliability of the new model compared to the earlier, EGM96-based and somewhat tilted regional geoid models for the same study area.

  • 372.
    Elming, Sten-åke
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    A palaeomagnetic and geochemical study of mafic dikes in northern Sweden1990In: Abstracts: Second Symposium on the Baltic Shield with Workshop on Correlation with Laurentia, Lund, Sweden June 5-7, 1990, Lund: International Geological Correlation Programme , 1990, p. 34-Conference paper (Other academic)
  • 373. Emo, Robert
    et al.
    Smit, Matthijs
    Schmitt, Melanie
    Swedish Museum of Natural History, Department of Geology.
    Kooijman, Ellen
    Swedish Museum of Natural History, Department of Geology.
    Scherer, Erik
    Sprung, Peter
    Bleeker, Wouter
    Mezger, Klaus
    Evidence for evolved Hadean crust from Sr isotopes in apatite within Eoarchean zircon from the Acasta Gneiss Complex2018In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 235, p. 450-462Article in journal (Refereed)
    Abstract [en]

    Current models for the properties of Hadean-Eoarchean crust encompass a full range of possibilities, involving crust that is anywhere from thick and differentiated to thin and mafic. New data are needed to test and refine these models, and, ultimately, to determine how continents were first formed. The Rb-Sr system provides a potentially powerful proxy for crustal evolution and composition. However, this system has thus far been underutilized in studies on early crustal evolution due to its susceptibility to re-equilibration. Overcoming this issue requires new analytical approaches to micro-sample ancient Sr-rich mineral relics that may retain primary Rb-Sr systematics, allowing for the precise and accurate determination of initial 87Sr/86Sr values. In this study, we used a novel application of laser-ablation multi-collector inductively coupled plasma mass spectrometry to determine the Sr isotope composition of apatite inclusions in >3.6 Ga zircon grains from Eoarchean granodiorite gneisses of the Acasta Gneiss Complex, Slave Province, Canada. The 87Rb-corrected 87Sr/86Sr values of these inclusions are largely identical and are distinctly different from values obtained from altered matrix apatite. The inclusion data provide the first direct estimate of initial 87Sr/86Sr for these ancient rocks. Combining this result with information on the protolith and source-extraction age yields estimates for the range of Rb/Sr values, and by extension composition, that the source of these rocks may have had. The data indicate that continental crust containing over 60 wt% of SiO2 was present in the ca. 4.2 Ga source of the Acasta Gneiss Complex. Thus vestiges of evolved crust must have existed within the primitive proto-continents that were present on the Hadean Earth.

  • 374.
    Engström, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    An inter-laboratory calibration of Si isotope reference materials2006In: Vol. 70, no 18, Suppl. 1, p. A529-Article in journal (Refereed)
  • 375.
    Engström, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Fractionation of the stable silicon isotopes: analytical method developments and selected applications in geochemistry2007Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    During the last few decades, variations in the 'natural' isotopic abundances of stable elements (termed 'fractionation') have received considerable interest from the scientific community. Though analytical methods and techniques for the measurement of isotopic abundances with adequate figures of merit have been available for light elements (e.g. B, C, N and O) for some time, and the wealth of data produced has secured maturity status for such applications, relatively modest progress in fractionation studies devoted to high-mass elements has been made until recently, mainly because of constraints of the available analytical techniques. The situation has changed drastically with the advent of multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), with the number of reports about natural fractionation of Fe, Cu, Zn, Mo, Cd, Sn increasing exponentially during the recent years. In spite of the high Si abundance in nature and the importance of the element in many areas of the Earth sciences (focusing on e.g. weathering, the global Si cycle, paleoclimate studies, paleoceanography, and biological uptake), the available information on Si isotope fractionation remains rather limited due to the laborious and hazardous chemical purification procedures associated with the analyses. The focus of this thesis was the development of analytical methods for the precise and accurate measurements of Si isotope ratios, which is an absolute requirement for meaningful fractionation studies, in various matrices. This work involved detailed studies on sample preparation (including matrix separation) and refining the measurement protocol by using high resolution MC-ICP-MS. In the former stages, quantitative analyte recovery, thorough control of contamination levels and purification efficiency were the major targets, while severe spectral interferences and the need for adequate instrumental mass bias corrections challenged the latter. The performance of the method was tested in the first inter- laboratory performance assessment study of its kind with good results. As limited examples of applications, studies on Si isotope fractionation in aqueous, plant and humus samples were performed utilizing methods developed. The efficient analyte separation, high-resolution capability of the instrument, quantitative Si recovery and accurate mass bias correction using Mg as internal standard, allowed the determination of the Si isotopic composition of natural waters and biological samples with long-term reproducibility, expressed as twice the standard deviation (2σ), equal to or less than 0.10‰ for δ29Si and 0.25‰ for δ30Si. Furthermore, the presence of a challenging spectral interference on 29Si originating from 28SiH+ was revealed during this study, indicating that instrumental resolution in excess of 3500 is required for interference-free Si isotopic analyses. However, despite complete removal of N-, O-, and C-containing interferences appearing on the high-mass side of the Si isotopes, it was found that exact matching of both the acid matrix and the Si concentration are mandatory due to tailing from the abundant 14N16O+ interference on 30Si. This thesis also includes results from the first study of the Si isotopic homogeneity of major biomass components from a defined area in Northern Sweden covered by boreal forest. Since the potential impact of vegetation on the terrestrial biogeochemical cycle has attracted considerable interest, thorough characterization of the Si isotopic composition of the biomass potentially allows the utilization of this isotope system in the assessment of the relative contributions of biogenic and mineral silica in plants, soil solutions and natural waters (including fresh-, brackish- and marine waters). Isotopic analyses of the biological materials yielded a surprisingly homogenous silicon isotopic composition (relative to the NBS28 Si reference material), expressed as δ29Si (2σ), ranging from (- 0.14 ± 0.05)‰ to (0.13 ± 0.04)‰ Furthermore, elemental and isotopic analysis of local airborne particulate matter suggests that vegetation also accumulates silica via incorporation of exogenous Si containing primary and secondary minerals (in addition to root uptake of non-ionic silicic acid), a fact that has been neglected in previously published studies. This strongly indicates that the presence of potential surface contributions must be considered during in situ silicon uptake studies

  • 376.
    Engström, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Fractionation of the stable silicon isotopes studied using MC-ICP-MS: analytical method developments and applications in geochemistry2010Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    In spite of the high Si abundance in natural systems, expected significant mass-dependent fractionations, and the importance of the element in many areas of the Earth sciences (focusing on e.g. silicate weathering, global climate, paleoceanography, and biogeochemical Si cycling), the available information on Si isotope fractionation has remained rather limited due to the laborious and hazardous chemical purification procedures associated with the analyses. The initial focus of this thesis was therefore the development of analytical methods for the precise and accurate measurements of Si isotope ratios in a variety of matrices, which is an absolute requirement for meaningful fractionation studies. This involved detailed studies on sample preparation and refining the measurement protocol by using high resolution MC-ICP-MS. In the former stages, quantitative analyte recovery, thorough control of contamination levels and purification efficiency were the major targets, while severe spectral interferences and the need for adequate instrumental mass bias corrections challenged the latter. Efficient analyte separation, high-resolution capability of the instrument, quantitative Si recovery and accurate mass bias correction using Mg as internal standard, allowed the determination of the Si isotopic composition of Si reference materials, natural waters, plant and humus samples with long-term reproducibility, expressed as twice the standard deviation (2σ), equal to or less than 0.10‰ for δ29Si and 0.25‰ for δ30Si. Furthermore, the presence of a challenging spectral interference on 29Si originating from 28SiH+ was revealed, indicating that an instrumental resolution in excess of 3500 is required for interference-free Si isotopic analyses. However, despite complete removal of N-, O-, and C based interferences appearing on the high-mass side of the Si isotopes, it was found that exact matching of the acid matrix and Si concentration are mandatory due to tailing from the abundant 14N16O+ interference on 30Si. In addition, the condition of the high resolution slit is of the utmost importance for achieving highly accurate and precise δ30Si determinations.Methods developed were applied in geochemical studies aimed at increasing our knowledge of processes governing the terrestrial Si cycle in arctic and sub-arctic environments. This thesis includes results from the first study investigating the Si isotopic homogeneity of the major biomass component in Northern Sweden. The analyses revealed a narrow isotopically-light δ30Si range limited to (0.5 ± 0.2)‰ for bulk plant material averaging (-0.11 ± 0.18)‰, suggesting that Si isotopes might have the potential for use in the quantification of the biogenic impact on the biogeochemical cycle. Elemental analyses further revealed the presence of exogenous Si plant surface contaminations, a fact that has been neglected previously. This strongly indicates that potential surface Si contributions must be considered in biogeochemical studies.High-frequency sampling of the Kalix River system revealed detectable variations in the dissolved Si isotopic composition even on a daily basis. Hydrological modelling, elemental normalization and land cover analysis identified relative enrichments of dissolved Si originating from the forest covered areas and relative depletions from the mountainous lake areas as major processes controlling the Si budget in the system. The enrichments and depletions of dissolved Si were accompanied by decreased and increased δ30Si, suggesting that the forest areas are a source of isotopically-light Si to the system. The result of this study provides evidence that the formation and dissolution of biogenic silica has the potential to significantly affect the riverine Si budget and isotopic composition.Spatial dissolved Si isotope variations in the Lena River system, delta area and estuary suggest that processes controlling the Si budget in these systems are capable of altering the Si isotopic composition of the riverine end-member, a fact that must be considered in future studies. The isotopically-light Si isotopic composition in the Lena River, compared to data from boreal systems not underlain by permafrost, further strengthens the previous hypothesis of a significant biogenic impact in Siberia. Spatial variations in vegetation and permafrost cover, accompanied by detectable Si isotope differences, suggest that climatically induced permafrost thawing might have a significant impact on the riverine and marine Si isotope budget.

  • 377. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Förekomst av osmium och osmiumtetroxid i Norrbottens län2007Report (Other (popular science, discussion, etc.))
  • 378.
    Engström, Emma
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Baxter, Douglas
    Ingri, Johan
    Öhlander, Björn
    Characterization of the silicon isotopic composition of the terrestrial biogenic output from a boreal forest in Northern Sweden2007In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 71, no 15s, p. A256-Article in journal (Other academic)
    Abstract [en]

    During the last decade, the potential plant impact on the biogeochemical cycle of Si via the large terrestrial biogenic Si reservoir formed by vegetation has attracted considerable interest. It has been concluded that the release of silicic acid from dissolution of soil phytoliths might exceed the Si mobilized by weathering of Si-containing primary minerals, which implies that the biogenic contribution to the total content of Si in the soil profile must be considered in weathering studies. Information about Si isotopes can potentially be used for differentiation between relative contributions from biogenic and mineral sources in natural waters, soil solutions and plants. This would, however, require thorough characterization of the terrestrial biogenic Si reservoir, a task that received somewhat limited attention to date. The aim of the present study was to characterize the Si isotopic composition of a boreal forest, with bedrock consisting of dolomitic limestone, in Northern Sweden. Representative biomass from the forest area exhibited a surprisingly homogenous Si isotopic composition, ranging from δ29Si (-0.14 ± 0.05)‰ (2σ) to (0.13 ± 0.04)‰. Further, a change in the Si isotopic composition of (+0.39 ± 0.04)‰ has been detected in Leymus arenarius, indicating predominant accumulation of heavier isotopes from spring to autumn. Recent studies of Si isotopic composition in plants have been focused on the root uptake of dissolved silicic acid as the only Si accumulation path. Results acquired during the present study provide compelling evidence to suggest that exogenous Si is also incorporated in the surface structure of the plant material. A surface contribution in excess of 5% of the total Si would introduce a significant shift in the bulk isotopic composition (>0.1‰) assuming that the exogenous material differed by 2‰ from the biogenic Si. This strongly suggests that the surface contribution must be carefully considered during in situ uptake studies.

  • 379.
    Engström, Emma
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Baxter, Douglas
    Öhlander, Björn
    Chromatographic purification for the determination of dissolved silicon isotopic composition in natural waters by high-resolution multicollector inductively coupled plasma mass spectrometry2006In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 78, no 1, p. 250-257Article in journal (Refereed)
    Abstract [en]

    A procedure is described for accurate Si isotope ratio measurements by multicollector inductively coupled plasma mass spectrometry (MC-ICPMS). Dissolved silicon was preconcentrated and separated from other elements present in natural surface waters using anion-exchange chromatography. The optimized procedure provides virtually complete elimination of major inorganic constituents while maintaining Si recovery in excess of 97%. High-resolution capabilities of MC-ICPMS used in this study allow interference-free measurements of 28Si and 29Si isotopes using conventional solution nebulization sample introduction without aerosol desolvation. Owing to the magnitude of polyatomic ion contributions in the region of mass 30, mostly from 14N16O+, measurements of the 30Si isotope can be affected by tailing of the interference signals, making exact matching of analyte and nitric acid concentrations in all measurement solutions mandatory. Isotope abundance ratio measurements were performed using the bracketing standards approach and on-line correction for mass-bias variations using an internal standard (Mg). Uncertainties, expressed as 95% confidence intervals, for replication of the entire procedure are better than ±0.18" for δ29Si and ±0.5" for δ30Si. For the first time with MC-ICPMS, the quality of Si isotope abundance ratio measurements could be verified using a three-isotope plot. All samples studied were isotopically heavier than the IRMM-018 Si isotopic reference material.

  • 380. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ingri, Johan
    Baxter, Douglas
    Ecke, Frauke
    Österlund, Helene
    Öhlander, Björn
    Temporal isotopic variations of dissolved silicon in a pristine boreal river2009In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, no 13, Suppl. S, p. A333-Article in journal (Other academic)
    Abstract [en]

    Interest in quantifying the biogenic impact on the terrestrial biogeochemical Si cycle has increased significantly since biological control has been suggested. Previous observations of isotopic fractionation of Si during biogeochemical and geochemical processes imply that seasonal dissolved Si isotopic patterns in rivers have the potential for use in extracting information about the riverineand terrestrial biogeochemical Si cycles.Therefore, variations in the isotopic composition of dissolved riverine Si were investigated for the Kalix River, Northern Sweden, one of the largest pristine rivers in Europe, based on high-frequency sampling during a period of 25 weeks from early April to early October 2006. Temporal variations spanning 0.4. for δ29Si and 0.8. for δ30Si of dissolved Si in the Kalix River were observed during the period, suggesting that the riverine Si input to the oceans cannot be considered to have a constant Si isotopic composition even on a short time scale. The results implicate biogeochemical Si-cycling via formation and dissolution of biogenic silica as major processes controlling the Si transport in boreal systems. The Si budget in the river system appeared to be controlled by relative Si accretions during high discharge events and relative Si depletions in the subarctic mountainous and lake dominated areas. There were also temporal variations in Si isotopic composition with accretion (relative Si contribution), accompanied by depletion of the heavier Si isotopes, while the opposite trend was observed during periods of riverine Si depletion. These isotope variations can be explained by release of plant derived silica, depleted in heavier Si isotopes, during the spring snowmelt. Further, increased volumetric contribution from the headwater and losses of Si due to biogenic silica formation by diatoms in the subarctic lakes at a later period are expected to be responsible for the preferential losses of lighter isotopes. These conclusions are further verified by land cover analysis.

  • 381.
    Engström, Emma
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ingri, Johan
    Baxter, Douglas
    Ecke, Frauke
    Österlund, Helene
    Öhlander, Björn
    Temporal isotopic variations of dissolved silicon in a pristine boreal river2010In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 271, no 3-4, p. 142-152Article in journal (Refereed)
    Abstract [en]

    It has previously been concluded that the stable Si isotopes are fractionated during geochemical and biogeochemical elemental transfers, such as weathering and precipitation of clays and biogenic Si, which has opened up the possibility of using Si as a tracer in natural terrestrial ecosystems. Furthermore, quantification of the biogenic impact on the biogeochemical Si cycle has attracted significant scientific interest since biological control has been suggested. Previous observations of seasonal variations in the dissolved Si isotopic pattern further imply that high-frequency riverine sampling during main hydrological events might provide important information about natural processes governing the fluvial biogeochemical Si cycle.Therefore, temporal variations in the isotopic composition of riverine dissolved Si were investigated for the Kalix River, Northern Sweden, the largest pristine river system in Europe, based on high-frequency sampling during a period of 25 weeks from early April to early October 2006. Temporal variations spanning 0.4‰ for δ29Si and 0.8‰ for δ30Si of dissolved Si in the Kalix River were observed during the period, suggesting that the riverine dissolved Si input to the oceans cannot be considered to have a constant Si isotopic composition even on a short time scale.The results implicate biogeochemical Si-cycling via formation and dissolution of biogenic silica as processes significantly affecting the dissolved Si transport in boreal systems during April to early October. The Si budget in the river system appeared to be controlled by relative Si enrichment during high discharge events and relative Si depletions in the subarctic mountainous and lake dominated areas. The Si enrichments and depletions were accompanied by decreasing and increasing riverine δ29Si and δ30Si, respectively. These isotope variations can be explained by release of plant derived silica, depleted in heavier Si isotopes, during the spring snowmelt. Further, increased volumetric contribution from the headwater and losses of dissolved Si due to biogenic silica formation by diatoms in the subarctic lakes at a later period are expected to be responsible for the preferential losses of lighter isotopes, as further verified by land cover analysis

  • 382. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Öhlander, Björn
    Ingri, Johan
    Baxter, Douglas
    Silicon isotopic composition of boreal forest vegetation in Northern Sweden2008In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 257, no 3-4, p. 247-256Article in journal (Refereed)
    Abstract [en]

    Thorough characterization of the Si isotopic composition of the terrestrial biogenic pool could potentially allow Si isotope information to be used when assessing the relative contributions from biogenic and mineral sources to soil water, plants and surface waters. In the present study, the Si isotopic compositions of major biomass components in a boreal forest in Northern Sweden were investigated, along with the relative contributions from exogenous Si incorporated in the plant structure. This was achieved using chemical purification and high-resolution multi-collector inductively coupled mass spectrometry (MC-ICP-MS) for the precise and accurate determination of the Si isotopic composition of plants. The technique, which relies on multi-elemental analysis of plant ashes and sample-specific HF-dissolution followed by strong-anion exchange chromatography, allows efficient separation of Si from matrix and interfering elements, while recovering in excess of 99% Si. The long-term instrumental reproducibility, expressed as two standard deviations (2σ), for the isotopic reference material NBS28 (n=12) was 0.06‰ for δ29Si and 0.12‰ for δ30Si. Results for the analyses of composite plant samples for the eight most prolific species in the boreal forest yielded a surprisingly homogenous Si isotopic composition, expressed as δ29Si (±expanded combined uncertainty) and δ30Si, ranging from (-0.15±0.11)‰ to (0.13±0.06)‰ and (-0.31±0.08)‰ to (0.22±0.13)‰, respectively. Isotopic and elemental analyses of local airborne particulate material suggest that the exogenous Si contribution varies between >1% and >70%, indicating that the potential surface contribution must be considered during Si uptake studies. The present study thus provides evidence that thorough appreciation of the forms of Si in plants is an absolute requirement when assessing the plant impact on the Si cycle via the difference in dissolution kinetics for phytoliths and lithogenic Si.

  • 383.
    Engström, Emma
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Stenberg, Anna
    Luleå tekniska universitet.
    Baxter, Douglas
    Malinovskiy, Dmitry
    Irma, Mäkinen
    Finnish Environment Institute.
    Pönni, Seppo
    Pirkanmaa Regional Environment Centre.
    Rodushkin, Ilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Effects of sample preparation and calibration strategy on accuracy and precision in the multi-elemental analysis of soil by sector field ICP-MS2004In: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 19, p. 858-866Article in journal (Refereed)
    Abstract [en]

    Soil samples were prepared for multi-element analysis using HNO3 leaching or pseudo-total digestion with HNO3, HCl and HF in a microwave oven, both methods requiring 70 min heating time. Two calibration approaches for the soil characterization were also compared: external calibration, combined with internal standardization, and isotope dilution (ID) after appropriate spiking of the soils with a stable isotope mixture prior to sample preparation. Analyses were performed using inductively coupled plasma sector field mass spectrometry (ICP-SFMS). Accurate total elemental concentrations were only obtained for Cd and P using both sample preparation methods in two certified reference materials, NIST SRM 2709 and CCRMP SO-2, as well as comparable values for a Finnish inter-laboratory soil. The pseudo-total digestion method also provided accurate results for As, Be, Co, Fe, Mn, Ni, Pb, Sb, Ti, V and Zn. For Cu in SO-2 and Cr in both certified reference materials, incomplete recoveries were always obtained. In the case of Cr, this is due to difficulties associated with the complete solubilization of refractory minerals.For a given final dilution factor, external calibration provides better limits of detection (LODs) than ID. As both methods of quantification yield results of essentially equivalent accuracy and precision, external calibration is to be preferred as a greater number of elements are amenable to analysis in a shorter measurement time. On the other hand, ID can be combined with matrix separation (NH3 precipitation was used here), allowing lower dilution factors to be used without deleterious effects on the instrumental performance. In particular, improved LODs could be obtained for Cd, Cu and Hg, primarily as a result of being able to introduce ten-fold more concentrated solutions from which the bulk of the matrix had been removed. For Cu and Ni, matrix separation almost eliminated Ti, and thus the formation of spectrally interfering TiO+ was completely suppressed. Potentially, the combination of ID and matrix separation would allow these elements to be determined without resorting to medium resolution measurement mode, again improving the LODs for the determination by ID-ICP-SFMS.

  • 384. Engström, Emma
    et al.
    Stenberg, Anna
    Luleå tekniska universitet.
    Senioukh, Svetlana
    ALS Analytica AB, Luleå.
    Edelbro, Roland
    ALS Analytica AB, Luleå.
    Baxter, Douglas
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Multi-elemental characterization of soft biological tissues by inductively coupled plasma-sector field mass spectrometry2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 521, no 2, p. 123-135Article in journal (Refereed)
    Abstract [en]

    The performance of double-focusing, sector field ICP-MS (ICP-SFMS) for the multi-elmental analysis of soft tissues following microwave-assisted digestion with nitric acid was eveluated and factors affecting method limits of detection discussed. Accuracy was assessed by replicate analyses of certified reference materials and by participation in performance evaluation programs; the precision was better than 5% relative standard deviation (RSD) for the majority of elements. Cl was the only element for which ICP-SFMS data consistently deviated from certified concentrations in the reference materials tested. Comparison between results obtained by ICP-SFMS and ICP optical emission spectrometry showed good agreement for elements present in tissues at concentrations above 2 μg g-1. The concentrations of 68 elements in different fish and animal soft tissues (muscle, liver, kidney, lung and brain) are presented, and, where possible, compared to previously published data.

  • 385.
    Engström Johansson, Alexandra
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Single-Grain Zircon U-Pb Dating and Magnetic Susceptibility of Polish Loess to Determine Late Quaternary Dust Provenance and Paleoclimate2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Windblown mineral dust has accumulated into thick loess layers across the European continent. Loess deposits are valuable paleoclimatic archives as they record climate change on centennial- to glacialinterglacial timescales. A reliable identification of dust sources is of fundamental importance for paleoclimatic reconstructions of atmospheric circulation patterns and dust pathways, and for understanding the link between mechanisms of dust production and -emissions and climate change.

    European dust sources are however still relatively poorly constrained, which in part is related to the few provenance studies performed using single-grain techniques. Single-grain techniques, and in particular single-grain U-Pb dating of detrital zircons, may allow for a reliable identification of multiple individual sources, as has been shown for the Chinese loess archive. Few dust provenance studies in general, and none found using single-grain techniques, have been performed on Polish loess samples. The location of Polish loess deposits in the central parts of the European continent may allow for a more complete paleoclimatic picture by tying together provenance studies from west to east, as well as for distinguishing between the proposed central European dust source areas of distal Fennoscandia and the proximal mountains of Moravia, the Alps, the Sudetes, the Bohemian Massif and the Carpathians.

    Forty-two loess samples were collected from the Biały Kościół loess profile in southwestern Poland, spanning deposition ages from the Eemian to the Holocene (MIS 5-1). Five samples were dated using single-grain zircon U-Pb geochronology and thirty-seven samples were measured and analysed using magnetic parameters of mass-specific-, frequency- and phase dependent susceptibility which reflect changes in mineralogy and grain size of magnetic mineral fractions. Magnetic susceptibility results show variations between and within stratigraphic units. Different soil formation processes appear to have been dominant during the three paleosol units (Holocene, MIS 3, MIS 5), while variability in magnetic susceptibility during MIS 4 and 2 may be related to source changes caused by changes in climatic conditions. Single-grain zircon U-Pb age distribution data indicate similar dust provenance for the Biały Kościół loess since the Eemian, with a very prominent age peak at ca. 325 Ma that is reflected to varying degree in all other sediment samples. The prominence and relative importance of the 325 Ma peak is best matched by sites along the lower Danube and the Tisza River, and corresponds to crustal rock ages related to the Variscan orogeny. Variscan source terranes can be found across central Europe and may suggest the outer Western Carpathians and the Bohemian Massif as potential primary source rocks for the Biały Kościół loess.

  • 386.
    Enholm, Zacharias
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Petrografisk-mineralkemisk karakterisering av Muonionalustameteoriten2012Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna uppsats består av två delar, den första behandlar kortfattat elementens och solsystemets genes för att fortsätta med en mer omfattande beskrivning av meteoriterna, deras klassifikation, mineralogi och upprinnelse. Den andra delen av uppsatsen beskriver prepareringen, innefattande montering, slipning, polering och etsning, samt undersökningen av Muonionalustameteoriten. Muonionalusta är en Fe,Ni-meteorit av typen oktaedrit tillhörande den kemiska gruppen IVA. Meteoriten undersöks både med hjälp av malmmikroskopi och med FE-EPMA/WDS-analys. Fem stycken metalliska faser identifierades, nämligen kamacit, taenit, troilit, schreibersit och daubréelit samt viss förekomst av vad som tros vara kromit. Texturer av olika slag identifierades även, däribland chockinducerade Neumannlinjer.

  • 387.
    Enmark, Thomas
    Luleå tekniska universitet.
    A versatile interactive computer program for computation and automatic optimization of gravity models1981In: Geoexploration, ISSN 0016-7142, Vol. 19, no 1, p. 47-66Article in journal (Refereed)
    Abstract [en]

    A computer program for computation and automatic optimization of gravity models is presented. The basic model used is a 21/2 dimensional body, i.e. a body of polygonal cross-section with the tails in the strike direction cut off. An optimization procedure that computes the best model in the least-squares sense, is described. The main program and two subroutines are reproduced. The optimization of complicated models composed of several bodies of arbitrary lengths, shapes, densities etc. takes typically no more than about 1-2 min on a medium sized computer with the program described

  • 388.
    Enmark, Thomas
    Luleå tekniska universitet.
    Development of optimization procedures for gravity and magnetic interpretation and their application to some geological structures in northern Sweden1982Doctoral thesis, comprehensive summary (Other academic)
  • 389.
    Enmark, Thomas
    Luleå tekniska universitet.
    The plausibility of some deep structure models in the Skellefte field in Northern Sweden1981In: Vol. 19, no 2, p. 144-145Article in journal (Other academic)
  • 390.
    Enmark, Thomas
    et al.
    Luleå tekniska universitet.
    Nisca, Dan H.
    The Gallejaur Intrusion in northern Sweden: a geophysical study1983In: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 105, no 4, p. 287-300Article in journal (Refereed)
    Abstract [en]

    Geophysical and geological models of the Gallejaur structure in northern Sweden are presented. The plausibility of each of them is discussed. It is shown that the models so far suggested, as interpreted mainly on the basis of geological mapping, are not compatible with petrophysical studies combined with gravity and magnetic data. An alternative model of the Gallejaur structure based on combined geological, petrophysical and geophysical interpretation is suggested. The structure is interpreted as a large rounded mafic laccolith intrusion with a shallow cap of monzonite derived by differentiation at the top. The maximum depth extent of the structure is calculated to be about 3.5 to 4.5 kilometres.

  • 391.
    Entwistle, Jane A.
    et al.
    Department of Geography and Environmental Sciences, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST, UK.
    Amaibi, Patrick M.
    Department of Applied Sciences, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST, UK.
    Dean, John R.
    Department of Applied Sciences, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST, UK.
    Deary, Michael E.
    Department of Geography and Environmental Sciences, Northumbria University, Ellison Building, Newcastle upon Tyne NE1 8ST, UK.
    Medock, Daniel
    Toxicology Department, Centre for Radiation, Chemical and Environmental Hazards, Public Health England, Chilton, Didcot, Oxon OX11 0RQ, UK.
    Morton, Jackie
    Health and Safety Executive, Harpur Hill, Buxton SK17 9JN, UK.
    Rodushkin, Ilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering. ALS Global Scandinavia, Aurorum 10, 977 75 Luleå, Sweden.
    Bramwell, Lindsay
    Institute of Health and Society, Medical Faculty, Newcastle University, Newcastle upon Tyne NE2 4AX, UK.
    An apple a day? Assessing gardeners' lead exposure in urban agriculture sites to improve the derivation of soil assessment criteria2019In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 122, p. 130-141Article in journal (Refereed)
    Abstract [en]

    Globally, many of our urban agriculture sites (UAS) contain high levels of lead (Pb), a contaminant of toxicological concern to humans. To improve the derivation of soil assessment criteria at UAS, and avoid inappropriate closure of these valuable community spaces, we sampled nearly 280 paired soil and crop samples across 31 UAS gardens. This sampling was coupled with an exposure and food frequency questionnaire and participants blood Pb levels (BLL), (43 gardeners and 29 non-gardening neighbours). In 98% of the sampled soils, Pb concentrations were above the current UK soil guideline for UAS (80 mg/kg), however despite the high soil Pb (geometric mean: 324 mg/kg), and high soil bioaccessible Pb (geometric mean: 58.7%), all participants BLL were <4.1 μg/dL (range: 0.6–4.1 μg/dL). Indeed, there was no statistically significant difference between the BLL of the UAS gardeners and those of their non-gardening neighbours (p = 0.569).

    Pb uptake, however, varied with crop type and our study highlights the suitability of certain crops for growing at UAS with elevated Pb (e.g. tubers, shrub and tree fruit), whilst limiting the consumption of others (selected root vegetables, such as rhubarb, beetroot, parsnips and carrots, with observed Pb concentrations > 0.1 mg/kg FW).

    The importance of defining the exposure scenario of a specific sub-population (i.e. UAS gardeners) is highlighted. Our preferred models predict site specific assessment criteria (SSAC) of 722–1634 mg/kg. We found fruit and vegetable consumption rates by all participants, and not just the UAS gardeners, to be considerably higher than those currently used to derive the UK's category 4 screening levels (C4SLs). Furthermore, the soil to plant concentration factors (SPCFs) used to derive the UAS C4SL significantly over predict Pb uptake. Our study indicates it may be appropriate to develop a distinct exposure dataset for UAS. In particular we recommend the derivation of SPCFs that are reflective of urban soils, both in terms of the range of soil Pb concentrations typically observed, but also the sources (and hence human oral bioaccessibility and plant-availability) of this Pb.

  • 392.
    Eriksson, Erik
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences, LUVAL.
    Hydrokemi: Om de kemiska processerna i vattnets kretslopp2012Book (Other academic)
  • 393.
    Eriksson, Sarah
    Uppsala University, Disciplinary Domain of Science and Technology, Earth Sciences, Department of Earth Sciences.
    Tracing the Origin of Metasedimentary Rocks in the Faroe-Shetland Basin2016Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    The Faroe-Shetland region has been exposed to a long history of tectonic events and the geology in the area is rather complex. This history has led to the formation large metasedimentary deposits, though the origin of these deposits is not yet fully understood. Possible source areas are Greenland, Norway and Scotland. To give a further understanding of the geology in the Faroe-Shetland basin and its regional relationship this study will analyze metasediments to classify them and compare them with other related sediments. Geochemical, petrographical and isotopic data will be for classification. Through this comparison it is evident that the metasediments from the Faroe-Shetland basin contain remnants from several different deposits and cannot be rated to one specific origin. This is shown by the 143Nd/ 144Nd , 87Sr/ 86Sr and 206Pb/204Pb , 207Pb/204Pb, 208Pb/204Pb isotope ratios found in the Faroe-Shetland basin compared with other possible source areas from Greenland, Norway and Scotland. This has shown that the isotope from the Faroe region correlate well with Caledonian traces from both Greenland and Scotland. Though the Torridonian sandstone from Scotland can also be correlated with the metasediments in the Faroe-Shetland basin.

  • 394. Erixon, Peter
    Igenväxning och vegetationsutbredning i Luleå innerfjärdar 1995-20042005Report (Other academic)
    Abstract [en]

    In 1992-1994 the local authority of Luleå dammed up the water in the four innermost bays of Luleå (Luleå innerfjärdar). The measures were taken to save the interconnected bays and prevent them become owergrown with aquatic plants and in the long run become svamps and land. The main causes of the succession from aquatic to terrestrial areas were land uplift ( about 1 cm/year), sedimentation eutrophication and owergrowth. A comparison between botanical investigations, including field inventories and analyses of air photgraphs, for the years 1995 and 2004 establish the following facts: In the four dammed up bays, Björkskata-, Björsby-, Sink- and Sörfjärden, the areas of aquatic vegetation are decreased and the density of plants have been reduced. There are much more areas of clean watersurfaces 2004 then 1995. Common Reed (Phragmites australis), which in 1994 made a big contribution to the owergrown situation in the bays, are considrably decreased. Other species that are decreased are Schoenoplectus lacustris, Potamogeton natans, Potamogeton perfoliatus, Sagittaria natans, Ranunculus peltatus and Elodea canadensis The principal cause of the reduction of aquatic vegetation in the innermost bays must be the higher water level during the vegetative period caused by the weirs. In Skurholmsfjärden, outside the weirs, there have been a slight increase of the watervegetation during the ten years period of studies. Here, in opposite to the other bays, the meanwaterlevel have sunk about 10 cm from 1995 to 2004. If it is possible to raise the meanwaterlevel in the innermost bays of Luleå a little bit more (10-20 cm) the reducing effect of the vegetation most likely will be even more noticeable than during 1995-2004. If more reduction of water vegetation in Luleå innerfjärdar is desired take the following measures into consideration: to pump water into the bays to get a higher waterlevel. to reduce the outlet of nutrients from different antropogenic sources. to accept owergrowth in some selected parts of the bays where the effects of recreation and aestheticall values are small. These parts will act like a sewage treatment plant and the water quality will be better with less nutrients in other parts of the bay-system which will slow down the owergrowth.

  • 395.
    Erixon, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Inpumpning av vatten till Luleå innerfjärdar - MKB: alternativa lösningar - hydrologiska, vattenkemiska och vegetationsmässiga konsekvenser2009Report (Other academic)
    Abstract [sv]

    Luleå tekniska universitet har av Luleå kommun, tekniska förvaltningen, fått i uppdrag att utreda effekterna av inpumpning av externt vatten till de uppdämda Luleå innerfjärdar. Fem olika alternativ jämförs inledningsvis varav två efter urval utgör huvudalternativen för den fortsatta miljökonsekvensbedömningen. Som grund för jämförelsen och bedömningen vilar resultaten från tidigare utredningar om innerfjärdarnas hydrologiska, vattenkemiska och ekologiska status. Resultaten från utredningen kan sammanfattas:Bedömningen görs att inpumpningens vattenståndshöjande effekt är den enskilt största faktor som påverkar vattenvegetationens utbredning i innerfjärdarna, genom att märkbart reducera denna. Den inverkan som valet av pump- och strömriktning har på växternas utbredning är förmodligen marginell, Av de två huvudalternativ för inpumpning av vatten som jämförs måste en inpumpning från Skurholmsfjärden förordas före en inpumpning från Mulöviken/Hagaviken på grund av följande orsaker/förhållanden:Läckaget i likskärsbanken försvårar en inpumpning över denna damm betydligt.En inpumpning från Skurholmsfjärden överensstämmer med den naturliga strömbild som nu råder i fjärdarna.En inpumpning från Skurholmsfjärden överensstämmer vattenkvalitetsmässigt bättre med det successionsstadie (den naturliga utvecklingen) som fjärdarna befinner sig idag 2005.Vatten inpumpat från Skurholmsfjärden håller högre vattenkemisk kvalitet än vatten från Mulöviken.· Vid en inpumpning från Skurholmsfjärden kommer fler fjärdbassänger att nås av vattenkvalitetsförbättringar. Detta gäller även den icke dämda SkurholmsfjärdenTrots att stor osäkerhet råder om läckagets storlek i främst likskärsbanken görs bedömningen att en pumpkapacitet på 0,5 m3/s kan vara tillräcklig för att under de flesta vädermässiga förhållanden fylla fjärdarna till bredden under perioden mitten av juni till slutet av september.Energiåtgången för att pumpa 0,5 m3/s under 3,5 månader är ca 9000 kWh. Dammkrönet vid lulsundskanalen måste höjas så att det ligger ca 10 cm över dammkrönet vid likskärsbanken.Ett kontrollprogram för inpumpningens inledande skede (provpumpning) presenteras. Föreliggande rapport skall tillsammans med resultaten från en föreslagen provpumning ingå i en slutlig och fullständig miljökonsekvensbeskrivning (MKB)

  • 396.
    Erixon, Peter
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Klimatstyrda sulfidoxidationer som orsak till surhet och höga metallhalter i vattendrag i norra Sverige2009Report (Other academic)
    Abstract [en]

    This study about existence, causes and effects of oxidations in sulphide-bearing sediments in the coastland of northen Sweden is based upon an unique waterchemical sample program during 1990-2007 including the following parameters: pH, alkalinity, colournumber (mg Pt/l), COD (Chemical Oxygen Demand), sulphate, totalphosphorus, totalnitrogen and conductivity. For the years 2003-2007 the program was supplemented with metals. This investigation focus on the waterchemistry in surface water in lakes, watercourses and estuaries. The main objectives of this study is to give valuable contribution to the answers of the following research questions: What characterize the total waterchemistry in surface water where sulphide oxidations occur in the catchment areas?What conditions are responsible for and determine the large waterchemical variation in the watercourses? What conditions regulate the episodes of accidification?What period in summer show the most pronounced impact from sulphide oxidation on surface water chemistry?What chemical reactions and mechanisms are responsible for the changing waterquality connected with episodes of acidification?How large are the conribution from sulphide oxidation to acidity and high metal concentrations in watercourses relatively other potential sources?In what amounts are metals transported out in the estuaries in the Bothnian Bay from small coastal watercourses compared to big mountain rivers?Have the metals different distrubution patterns in the estuary?What is the environmental and ecotoxicological effects of suldphide oxidations in coastal areas of the Bothnian Bay nowadays and in the future?What consequences have the existence of sulphide oxidations for environmental monitoring and management and for the implementation of the EU Water Frame Work Directive?Results and conclusions from the investigations can be summarized:(1) An extreme waterchemical variation occur in the watercourses within and between years, The existence of sulphide oxidations in the catchment areas are responsible for the extreme variation.(2) The climate in the investigation areas with its over time variable precipitiation causes large variations in the groundwater table which have an impact on and regulate the size of oxidations occuring in the catchments sulphide-bearing sediments and this in turn produces a large waterchemical variation in the watercourses (= ”Climate-induced sulphide oxidations”)(3) Episodes, with a total and radical change of the waterchemistry, occur in the watercourses as a result of climate-induced sulphide oxidations. This ”waterchemical reversal” is distinguished by the fact that previous high values for the parameters (group A:) pH, alkalinity, COD, colour, P, Fe and Cr will decrease considerable simultaneously as the concentrations for the parameters (group B:) sulphate, conductivity, Al, Cd, Co, Mn, Ni and Zn make a pronounced increase. All the results throughout this study show positive correlations between parameters in the same group (A or B) and negative correlations between the groups. During 1990-2007 there were at least three large climate-induced episodes of acidification with the waterchemical reversal here described.(4) Despite the huge waterchemical differens between identified episodes and more regular interepisodes, the relatively high concentration of metals and sulphur during the interepisodes confirms that oxidations in the catchments sulphide sediments constantly have an impact more or less on the waterquality of the surface water.(5) The size of sulphide oxidations in the catchment during different years are in the studied watercourse waterchemically more pronounced in june compared to maj or july. An explanation for those circumstances is presented.(6) Sulphide oxidations are the main cause to acidity and high metal concentrations in the investigated watercourses. The contribution to the pH-decline from factors such as increase in natural organic (humic) acidity or antropogenic acid deposition are of minor significance.(7) The total metal transport from Persöfjärden is of the same magnitude (Ni, Zn) or exceeds that in Kalix River (Al, Co, Mn) with a catchment approximately 100 times larger. The results from the studied watercourses indicate that the large number of small catchments i coastal areas in nothen Sweden could be a significant an so far unknown metal source for the Bothnian bay/Baltic Sea.(8) A metal-retention study shows that the metals transported in a stream have different distribution pattern in the estuary. The estuary acts like a significant trap for Al and Fe and like a source for Mn. For Co, Cd, Ni and Zn have more or less the same amounts that entered the estuary passed it. Mechanisms for the metals deposition to and leakage from the sediments are discussed.(9) To explain the chemical reactions and mechanisms responsible for the ”waterchemical reversal” with a significant decline of humic substances some hypothetical explanations are presented where Fe and Al are playing an important role in the flocculation of organic substances. The hypothesis support the consistently results that Fe have a high positive correlation and Al a negative correlation with organic substances (COD/ colour).(10) The significant positive correlations between phosphorous and COD/colour respectively iron indicate that the large decline in the concentrations of phosphorous during the episodes is due to the fact that phosphotous is removed from the water together with (1) flocculated organic substances and/or (2) precipitated iron.(11) Some observed ecotoxicological effects of the climate-induced sulphide oxidations are death of fish, increased distribution of some macrophytes, temporary dissappearance of some ”sea-birds” and absence of algae-blooming 1990-2007.(12) The unexpected high concentrations of cadmium found in liver from fish in the Bothnian Bay and the large variation between years could be the the result of the variable outflush of cadmium that natural climate-induced sulphide oxidations produce in coastal watercourses in northen Sweden and Finland.(13) The occurence of climate-induced sulphide oxidations have a radical impact on the waterchemical and biological parameters that are measured by routine in environmental monitoring. For that reason, for one thing to make it possible to discriminate antropogenic sources of acidity and high metal concentrations from natural sulphide oxidations, it is necessary to put specially demand for the design and interpretation of monitoring programs in sulphide-bearing ares. The climate induced sulphide oxidations have a significant impact on seven of Swedens 16 Environmental Objectives.

  • 397. Erixon, Peter
    Luleå innerfjärdar: Rapport A: Vattenkvalitet, bottenkvalitet, vegetation1996Report (Other academic)
    Abstract [sv]

    På grund av bl a landhöjningen håller Luleå innerfjärdar på att växa igen. Genom ett uppdämningsföretag (1993) hoppas man kunna bevara innerfjärdarnas landskapsestetiska och rekreativa värden. Undersökningens huvudsyften är att kartlägga innerfjärdarnas nuvarande och framtida förhållanden när det gäller vattenkvalitet, bottenkvalitet och vegetationsutbredning. En bedömning av vattnets kvalitet (närsalter, syre, ljusförhållanden och försurning) redovisas och havets betydelsefulla roll som vattenkvalitetspåverkare visas. Bottnarnas hårdhet, organiska halt och syrestatus beskrivs. Vegetationens utbredning, täthet och artsammansättning redovisas. Storleken på landtillvinningens och vegetationsutbredningens hastighet under de senaste femtio åren visas i kartform. Tre scenarier som visar hur innerfjärdarna ser ut år 2050 när det gäller landtillvinning, vattenvegetation och vattenkvalitet under olika yttre förutsättningar presenteras. Principiella samt för innerfjärdarna specifika metoder att möta landhöjningen och den ökade eutrofieringen på diskuteras.

  • 398. Erixon, Peter
    Vattenkvalitet i Luleå innerfjärdar 1990-20042005Report (Other academic)
    Abstract [sv]

    Luleå tekniska universitet får i uppdrag att utreda vilka effekter på vattenkvaliteten de av Luleå kommun vidtagna vattentekniska åtgärder 1992-1994 har fått i Luleå innerfjärdar. Genom bearbetning och analys av flera vattenkemiska provtagningsprogram mellan åren 1990-2004 kan följande slutsatser dras: Efter det att de vattentekniska åtgärderna vidtogs 1992-94 har inga dramatiska förändringar av vattenkvaliteten skett. Halter och värden ligger i stort kvar på samma nivåer som innan åtgärderna vidtiogs. Om de vattentekniska åtgärdena inte hade vidtagits hade inte innerfjärdarna haft en bättre vattenkvalitet än vad de har idag. Halter och värden hade då legat på ungefär samma nivåer som de gör i de uppdämda fjärdarna idag. Innerfjärdarnas vatten måste betecknas som förhållandevis näringsrika, de centrala delarna Holmsundet och Björsbyfjärden mer än de yttre. Den ovanliga vattenkvaliteten med höga metallhalter och låga pH-värden under 2003 och speciellt 2004 beror med mycket stor sannolikhet på klimatgenererade sulfidoxidationer i avrinningsområdet. De i innerfjärdarna upplagda muddermassornas bidrag till de höga metallhalterna är med mycket stor sannolikhet marginellt. De mångfalt förhöjda metallhalterna och låga pH-värdena beror med stor sannolikhet inte på metallindustriell verksamhet i området. Inga märkbara förändringar av vattenkvaliteten i fjärdarnas olika delar kan uppmärksammas till följd av den förändrade strömriktning som som de vattentekniska åtgärderna medförde. Havets vattenkvalitetshöjande effekt är mycket begränsad under perioden maj till mitten av september.

  • 399.
    Eshagh, Mehdi
    KTH, School of Architecture and the Built Environment (ABE), Urban Planning and Environment, Geodesy and Geoinformatics.
    On the reliability and error calibration of some recent Earth's gravity models of GOCE with respect to EGM082013In: ACTA GEOD GEOPHYS, ISSN 2213-5812, Vol. 48, no 2, p. 199-208Article in journal (Refereed)
    Abstract [en]

    The Gravity field and steady-state Ocean Circulation Explorer (GOCE) mission is dedicated to recover spherical harmonic coefficients of the Earth's gravity field to degree and order of about 250 using its satellite gradiometric data. Since these data are contaminated with coloured noise, therefore, their inversion will not be straightforward. Unsuccessful modelling of this noise will lead to biases in the harmonic coefficients presented in the Earth's gravity models (EGMs). In this study, five of the recent EGMs of GOCE such as two direct, two time-wise and one space-wise solution are used to degree and order 240 and their reliability is investigated with respect to EGM08 which is assumed as a reliable EGM. The detected unreliable coefficients and their errors are replaced by the corresponding ones from EGM08 as a combination strategy. A condition adjustment model is organised for each two corresponding coefficients of GOCE EGMs and EGM08; and errors of the GOCE EGMs are calibrated based on a scaling factor, obtained from a posteriori variance factor. When the factor is less than 2.5 it will be multiplied to the error otherwise the error of EGM08 coefficient will be considered as the calibrated one. At the end, a simple geoid estimator is presented which considers the EGMs and their errors and its outcomes are compared with the corresponding geoid heights derived from the Global Positioning System (GPS) and the levelling data (GPS/levelling data), over Fennoscandia. This comparison shows that some of the combined-calibrated GOCE EGMs are closer to the GPS/levelling data than the original ones.

  • 400.
    Eshagh, Mehdi
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    Kiamehr, Ramin
    KTH, School of Architecture and the Built Environment (ABE), Transport and Economics (closed 20110301).
    A Strategy for Optimum Designing of the Geodetic Networks from the Cost, Reliability and Precision Views2007In: Acta Geodaetica et Geophysica Hungarica, ISSN 1217-8977, E-ISSN 1587-1037, Vol. 42, no 3, p. 297-308Article in journal (Refereed)
    Abstract [en]

    There are different criteria for designing a geodetic network in an optimal way. An optimum network can be regarded as a network having high precision, reliability and low cost. Accordingly, corresponding to these criteria different single-objective models can be defined. Each one can be subjected to two other criteria as constraints. Sometimes the constraints can be contradictory so that some of the constraints are violated. In this contribution, these models are mathematically reviewed. It is numerically shown how to prepare these mathematical models for optimization process through a simulated network. We found that the reliability model yields small position changes between those obtained using precision respectively. Elimination of some observations may happen using precision and cost model while the reliability model tries to save number of observations. In our numerical studies, no contradictions can be seen in reliability model and this model seems to be more suitable for designing of the geodetic and deformation networks.

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