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  • 1.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Andrusikiewicz, Waclaw
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Bilstad, Torleiv
    Cala, Marek
    Cholewa, Marcin
    Drielsma, Johannes
    Galos, Krzysztof
    Gehör, Seppo
    Karu, Veiko
    Kotarska, Izabela
    Koch, Lutz
    Kreisel, Stefan
    Kuiala, Kauko
    Kulczycka, Joanna
    Ostrega, Anna
    Repo, Hanna
    Sädbom, Stefan
    Szcech, Anna
    Szlugaj, Jaroslaw
    Szmigielski, Piotr
    Swierczynski, Wieslaw
    Uberman, Ryszard
    Valgma, Ingo
    Wrzosek, Krzysztof
    Mining waste management in the Baltic Sea Region: Min-Novation project2013Book (Refereed)
  • 2.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Cala, Marek
    Ostreca, A.
    Reclamation and revitalisation of waste dumps or land after waste recovery2013In: Mining waste management in the Baltic Sea Region: Min-Novation project / [ed] Marek Cała, Krakow: Wydawnictwa AGH , 2013, p. 195-236Chapter in book (Refereed)
  • 3.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Häller, Sara
    Örebro University, School of Science and Technology.
    Panova, Elena
    St Petersburgs universitet, St Petersburg, Ryssland.
    Grawunder, Anja
    Friedrich Sciller Univ., Jena, Germany.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Water chemistry and trace metal concentrations in an acidic alum shale pit lake: effects of liming2011In: Mine water: managing the challenges: proceedings of the International Mine Water Association Congress 2011 / [ed] Trude R.Rüde, Antje Freund, Christian Wolkersdorfer, Aachen: RWTH , 2011, p. 503-508Conference paper (Refereed)
  • 4.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Grawunder, Anja
    Institute of Geoscience, Friedrich Schiller University, Jena, Germany .
    Neutralisation of an acidic pit lake by alkaline waste products2014In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 21, no 11, p. 6930-6938Article in journal (Refereed)
    Abstract [en]

    A former open pit where black shale (alum shale) was excavated during 1942-1965 has been water filled since 1966. The water chemistry was dominated by calcium and sulphate and had a pH of 3.2-3.4 until 1997-1998, when pH was gradually increasing. This was due to the intrusion of leachates from alkaline cement waste deposited close to the lake. A stable pH of around 7.5 was obtained after 6-7 years. The chemistry of the pit lake has changed due to the neutralisation. Concentrations of some dissolved metals, notably zinc and nickel, have gone down, as a result of adsorption/co-precipitation on solid phases (most likely iron and aluminium hydroxides), while other metals, notably uranium and molybdenum, are present at elevated levels. Uranium concentration is reaching a minimum of around pH 6.5 and is increasing at higher pH, which may indicate a formation of neutral and anionic uranyl carbonate species at high pH (and total carbonate levels around 1 mM). Weathering of the water-exposed shale is still in progress.

  • 5.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kumla, Sweden.
    Sjöberg, Viktor
    Örebro University, School of Science and Technology.
    Sädbom, Stefan
    Bergskraft Bergslagen AB, Kumla, Sweden.
    Control of metal releases from historic sulphidic mine waste: Experience from the test site at the Ljusnarsberg mine field, Sweden (Project Bergskraft Bergslagen)2010In: Proc. EU Mine Drainage Research Exchange Conf. PADRE, June 11, Freiberg, Germany, 2010, p. 1 p-Conference paper (Refereed)
  • 6.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB.
    Sädbom, Stefan
    Bergskraft Bergslagen.
    Strategy for treatment of historic sulphidic mine waste: Experiences from the Ljusnarsberg Mine Field, Sweden2009In: Proc. 12th EuCheMS International Conference on Chemistry and the Environment, June 14-17, Stockholm, 2009, p. 197-Conference paper (Refereed)
  • 7.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Metal releases from historic sulphidic mine site (Ljusnarsberg, Sweden): mobilization and attenuation processes2008Conference paper (Refereed)
  • 8.
    Angelstam, Per
    et al.
    Örebro University, School of Science and Technology.
    Andersson, Kjell
    Isacson, Maths
    Gavrilov, Dmitri V.
    Axelsson, Robert
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Degerman, Erik
    Elbakidze, Marine
    Kazakova-Apkarimova, Elena Yu.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Sadbom, Stefan
    Törnblom, Johan
    Örebro University, School of Science and Technology.
    Learning about the history of landscape use for the future: consequences for ecological and social systems in Swedish Bergslagen2013In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 42, no 2, p. 146-159Article in journal (Refereed)
    Abstract [en]

    Barriers and bridges to implement policies about sustainable development and sustainability commonly depend on the past development of social-ecological systems. Production of metals required integration of use of ore, streams for energy, and wood for bioenergy and construction, as well as of multiple societal actors. Focusing on the Swedish Bergslagen region as a case study we (1) describe the phases of natural resource use triggered by metallurgy, (2) the location and spatial extent of 22 definitions of Bergslagen divided into four zones as a proxy of cumulative pressure on landscapes, and (3) analyze the consequences for natural capital and society. We found clear gradients in industrial activity, stream alteration, and amount of natural forest from the core to the periphery of Bergslagen. Additionally, the legacy of top-down governance is linked to today's poorly diversified business sector and thus municipal vulnerability. Comparing the Bergslagen case study with other similar regions in Russia and Germany, we discuss the usefulness of multiple case studies.

  • 9.
    Benyamine, Michelle
    et al.
    Örebro University, Department of Natural Sciences.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Sandén, Per
    Multi-objective environmental management in constructed wetlands2004In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 90, no 1-3, p. 171-185Article in journal (Refereed)
    Abstract [en]

    We examined multi-objective environmental management as applied to pursuing concurrent goals of water treatment, biodiversity and promotion of recreation in constructed wetlands. A case study of a wetland established to treat landfill leachate, increase biodiversity, and promote recreation was evaluated. The study showed that attempts to combine pollution management with activities promoting biodiversity or recreation are problematic in constructed wetlands. This could be because the typical single-objective focus of scientific research leads to contradictions when planning, implementing and assessing the multi-objective use of wetlands. In the specific case of wetland filters for landfill leachate treatment, biodiversity, and recreation, there is a need for further research that meet practical needs to secure positive outcomes.

  • 10.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Environmental impact from an alum shale deposit, Kvarntorp, Sweden: Present and future scenarios2010In: Mine water & innovative thinking: proceedings 2010 / [ed] Wolkersdorfer, C. and Freund, A., Nova Scotia, Canada: Cape Breton University Press , 2010, p. 551-554Conference paper (Refereed)
    Abstract [en]

    During the second World War it was decided to produce oil through pyrolysis of alum shalegiving rise to waste products (coke and ash). Waste was deposited in the open pits and in a waste deposit.Due to the high remaining energy in the waste materials the waste deposit still today has significantlyelevated temperatures (above 500 °c). remaining pyrite in the waste material has also led to ArDwith elevated trace metal concentrations. the waste deposit is no great environmental problemtoday but as soon as the waste pile cools off both the volumes of drainage and concentrations oftrace metals will increase dramatically

  • 11.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    On the chemical state and mobility of lead and other trace elements at the biogeosphere/technosphere interface2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Most inorganic contamination has occurred at the interface between the technosphere and the biogeosphere, even though atmospheric emissions have affected the entire globe. Several human activities now pose a substantial threat towards human health and the ecosystems. It was thus decided to study lead as an element with significant anthropogenic emissions in a variety of sources and environments. Lead and other trace elements were studied in groundwaters used for drinking water, in roadside environments, at a shooting range and in a contaminated lake in order to obtain information about mobility and redistribution in different hydrobiogeochemical environments.

    It was found that 60% of the investigated drilled wells in crystalline bedrock failed to meet international health safety limits. This was mainly due to the presence of enhanced concentrations of fluoride and uranium.

    Along roads the concentrations and massfluxes increased significantly for lead, as well as for otheer elements during the winter. This is most likely due to increased pavement wear as a consequence of studded tires and use of deicing salts. The mobility of trace elements also increased in the roadside soils, threatening the shallow groundwater.

    At the shooting range it was found that the downward migration of lead was greater than expected and equilibrium with cerussite was suggested from solid speciation and geochemical calculations. Antimony was associated with lead and showed, despite differences in chemical properties, a similar distribution pattern. This was due to the fact that the major part of the transport at the shooting range was physical.

    In the contaminated lake, several findings regarding the solid speciation of lead was confirmed and other information about redistribution into the hypolimnion from the sediment was gained.

    List of papers
    1. Chemical character of drinking water from Swedish crystaline bedrock
    Open this publication in new window or tab >>Chemical character of drinking water from Swedish crystaline bedrock
    (English)Manuscript (preprint) (Other academic)
    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-15924 (URN)
    Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-10-17Bibliographically approved
    2. Speciation of heavy metals in road runoff and roadside total deposition
    Open this publication in new window or tab >>Speciation of heavy metals in road runoff and roadside total deposition
    Show others...
    2003 (English)In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 147, no 1-4, p. 343-366Article in journal (Refereed) Published
    Abstract [en]

    The concentrations of Cd, Co, Cu, Pb, W and Zn were measured in road runoff and total deposition at two Swedish field sites during one year. It was found that the concentrations of most elements increased significantly during the winter, up to one order of magnitude. For cobalt and tungsten, it was found that around 90% of the total mass transport occurred during the winter, whereas for Cu, Pb, Cd, Zn and Na, the corresponding figures were 70–90, 40–80, 60–90, 50–70 and >99% depending on site specific conditions. The deicing salts (rock salts) did not significantly contribute to the increase in trace element concentrations. Instead, the increased concentrations were due to more intense wearing of the pavement during the winter because of the use of studded tires in combination with the chemical effects caused by the use of deicing salts. New potential elemental markers for roads and traffic are suggested.

    National Category
    Natural Sciences
    Research subject
    Enviromental Science
    Identifiers
    urn:nbn:se:oru:diva-5196 (URN)10.1023/A:1024545916834 (DOI)
    Available from: 2009-01-30 Created: 2009-01-30 Last updated: 2017-12-14Bibliographically approved
    3. Mobilisation of heavy metals by deicing salts in a roadside environment
    Open this publication in new window or tab >>Mobilisation of heavy metals by deicing salts in a roadside environment
    Show others...
    2004 (English)In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 38, no 3, p. 720-732Article in journal (Refereed) Published
    Abstract [en]

    The seasonal variations of some selected heavy metals (Cd, Cu, Pb and Zn) and principal anions in soil solutions were monitored as a function of distance from the road at two field sites in Sweden. During the winter, the conductivity, concentrations of dissolved sodium and chloride increased dramatically due to the application of deicing agents (i.e. NaCl). Due to ion exchange, the pH decreased one unit in the soil solutions, whereas the concentrations of total organic carbon decreased due to coagulation and/or sorption to stationary solids. The heavy metal concentrations increased during the winter, but through different mechanisms. Cadmium concentrations in the aqueous phase increased as a response to ion exchange, possibly also enhanced by the formation of chloride complexes. Similarly, the concentrations of zinc increased, due to ion exchange, with calcium and protons. The mechanisms of mobilisation for copper and lead were not that clear probably due to association with coagulated or sorbed organic matter in combination with colloid dispersion

    National Category
    Natural Sciences
    Research subject
    Enviromental Science
    Identifiers
    urn:nbn:se:oru:diva-5200 (URN)10.1016/j.watres.2003.11.006 (DOI)
    Available from: 2009-01-30 Created: 2009-01-30 Last updated: 2017-12-14Bibliographically approved
    4. Metal leachability and anthropogenic signal in roadside soils estimated from sequential extraction and stable lead isotopes
    Open this publication in new window or tab >>Metal leachability and anthropogenic signal in roadside soils estimated from sequential extraction and stable lead isotopes
    2004 (English)In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 90, no 1-3, p. 135-160Article in journal (Refereed) Published
    Abstract [en]

    Several roadside soil samples were collected at two field sites in Sweden. They were analysed for total elemental content (using both ICP-MS and XRF) and stable lead isotopes. Extraction with deicing salt solution and sequential extraction were performed in order to elucidate the potential mobility due to the use of deicing agents. The total concentrations of elements, especially lead, have decreased and lead is presently almost at background concentrations (15–51 ppm for surface samples). However, the isotopic signature indicates that old gasoline lead still is left at the site constructed prior to 1975. The field site constructed in 1992 showed, however, no 206Pb/207Pb ratio below 1.14. Only minor amounts were leached using deicing salt solutions; for lead only 0.29%, on average, was extracted indicating that the mobile fraction already was released. Sequential extraction indicated that lead mainly was associated with reducible (34.4%) and oxidisable (35.4%) fractions. Exchangable and acid soluble fractions contained 20.3% while 10.0% was found in the residual fraction. The salt extraction released, however, very low concentrations indicating that most in fraction 1 is acid soluble (e.g. carbonates). Tungsten was also found at high concentrations indicating a possible impact from studded tires. For tungsten the following composition was obtained: residual (48.0%) > oxidisable (47.6%) > reducible (3.3%) > exchangeable/acid soluble (1.1%). From the isotopic studies it was also suggested that the order for incorporating anthropogenic lead into soils is exchangeable/carbonates > (hydr)oxides > organic matter > residual. The multivariate technique principal component analysis (PCA) seems promising for evaluating large sequential extraction datasets.

    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-5197 (URN)10.1023/B:EMAS.0000003572.40515.31 (DOI)
    Available from: 2009-01-30 Created: 2009-01-30 Last updated: 2017-12-14Bibliographically approved
    5. Factors affecting the dissolution of lead pellets in natural waters
    Open this publication in new window or tab >>Factors affecting the dissolution of lead pellets in natural waters
    (English)Manuscript (preprint) (Other academic)
    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-15925 (URN)
    Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-10-17Bibliographically approved
    6. Multielement contamination at a skeet and trap shooting range: I: mobility assessment through sequential extraction
    Open this publication in new window or tab >>Multielement contamination at a skeet and trap shooting range: I: mobility assessment through sequential extraction
    (English)Manuscript (preprint) (Other academic)
    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-15926 (URN)
    Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-10-17Bibliographically approved
    7. Multielement contamination at a skeet and trap shooting range: II: seasonal and spatial variations in surface and groundwaters
    Open this publication in new window or tab >>Multielement contamination at a skeet and trap shooting range: II: seasonal and spatial variations in surface and groundwaters
    (English)Manuscript (preprint) (Other academic)
    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-15928 (URN)
    Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-10-17Bibliographically approved
    8. Migration and mobility of lead and antimony from a heavily polluted lake sediment
    Open this publication in new window or tab >>Migration and mobility of lead and antimony from a heavily polluted lake sediment
    (English)Manuscript (preprint) (Other academic)
    National Category
    Chemical Sciences
    Research subject
    Chemistry
    Identifiers
    urn:nbn:se:oru:diva-15929 (URN)
    Available from: 2011-06-15 Created: 2011-06-15 Last updated: 2017-10-17Bibliographically approved
  • 12.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Bohlin, Hanna
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Holm, Nils
    Element (Ag, Cd, Cu, Pb, Sb, Tl and Zn), element ratio and lead isotope profiles in a sediment affected by a mining operation episode during the late 19th century2006In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 177, no 1-4, p. 285-311Article in journal (Refereed)
    Abstract [en]

    Mining operations at Maarsaetter in 1877-81 resulted in increased metal loading to a small lake, notably as sulphidic tailings. The event is taken as an opportunity to study the present environmental impact of a historical single major metal release. Lake water and four sediment cores were sampled and analysed for principal and trace elements in solid and aqueous phases as well as general hydrochemical conditions. Chronologies were determined from super(206)Pb/ super(207)Pb ratios and historical records.Ordinary sedimentation after the event has lead to that the tailings are found as a distinct layer at a depth of 18-22 cm in the sediment. The layer is characterized by elevated metal concentrations in the solid and pore water phases, respectively, circum neutral pH and sulphate concentrations below detection. Geochemical modelling indicated a preference for carbonate equilibrium in the waste while sulphides prevailed above it. It is concluded that the growth of the ordinary sediment on top of the waste has lead to a physicochemical barrier that seals of the waste from the overlying sediment. Chemical or physical rupture of the barrier will release the metals to downstream regions.According to the chronologies at least three sources have contributed to the present elevated levels of metals, in additions to the release of tailings. Copper from a historical blast furnace prior to the event at Maarsaetter, transport from mineralized parts of the watershed and release of contaminated water from present mining operations maintain elevated levels of notably zinc, silver, cadmium and lead. At present less than 10% of the lead content at the sediment/water interface comes from atmospheric deposition. Increased levels of antimony and thallium were not observed prior to ca 1950.

  • 13.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Börjesson, Erika
    SWECO VBB VIAK, SE-61132 Nykoping, Sweden.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Diurnal variations of abiotic parameters in a stream, recipient for drainage water in Ranstad, southwest Sweden2002In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 4, no 5, p. 772-777Article in journal (Refereed)
    Abstract [en]

    During 24 h, water samples were taken for determination of a number of key parameters in a water system containing high concentrations of FeII at circumneutral pH. None of the major constituents (Ca, Mg, Na, K and sulfate) showed diurnal variations, while dissolved oxygen and pH increased during the night. This increase could entirely be explained by the decrease in water temperature. However, the concentration of FeII slightly increased at constant concentration of total Fe during the night, opposite to earlier observations in other systems where the presence of FeII was shown to be controlled by photoreduction. Nocturnal peaks of FeII have also been observed in other systems with high iron concentrations, however, at acidic pH, but without obvious explanation. The mechanisms for this process therefore need further investigation.

  • 14.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Dario, Mårten
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Effects of a fulvic acid on the adsorption of mercury and cadmium on goethite2003In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 304, no 1-3, p. 257-268Article in journal (Refereed)
    Abstract [en]

    The effects of an aquatic fulvic acid on the pH-dependent adsorption of Hg(II) and Cd(II) to particulate goethite (a-FeOOH) were studied in batch systems. The ionic medium consisted of 0.01 M HClO and the total concentrations 4 of mercury and cadmium were maintained at 10y8 M with 203Hg and 109Cd as tracers. pH In the systems was varied in the range 3–10 by addition of HClO and NaOH.All commercial chemicals were of analytical grade or better. An 4 aquatic fulvic acid (20 ppm), previously isolated and characterised in detail, was used as a model for humic substances and its adsorption to goethite is included in this study. The adsorption of the fulvic acid (20 ppm) onto goethite decreased slowly from 90% at pH 3–7.5 to 10% at pH 10. In systems without fulvic acid the adsorption of mercury increased in a linear fashion from 10% at pH 3 to 70% at pH 10.In the presence of fulvic acid (20 ppm), the adsorption was almost quantitative in the intermediate pH range (pH 5–7), and exceeded 92% over the entire pH range. Thus, association between mercury and the fulvic acid enhanced adsorption in general although the largest impact was found at low pH.Adsorption of cadmium increased from nearly 0 to almost 100% at approximately pH 6. In the presence of fulvic acid, the adsorption increased below pH 7 and decreased above pH 7. The adsorption isotherm for mercury when the concentration was increased from 10y8 to 1.8=10y4 M showed a corresponding increase of K (lyg) up to a total concentration at 10y6 M.At higher mercury concentrations K was lowered. In the presence of fulvic acid the corresponding relationship of K was bi-modal, i.e. high values at low and intermediate concentrations of mercury. This behaviour suggests that in the absence of fulvic acid the adsorption follow the expected behaviour, i.e. adsorption sites with similar affinity for mercury. In the presence of fulvic acid, additional adsorption sites are available by the organic molecule (possibly sulfur groups) when it is associated to the goethite. The adsorption isotherm for cadmium indicates a lowering of K at 10y4 M. Cadmium had no competitive effect on mercury and vice versa. Zinc, however, affected the adsorption of cadmium but not the adsorption of mercury.

  • 15.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Domeij, Joel
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Flooding of oxidized waste rock amended with alkaline by-products2010In: 34th British Columbia Mine Reclamation & 35th CLRA/ACRSD National Conference, 2010, p. 10 pages-Conference paper (Refereed)
    Abstract [en]

    Leaching of trace elements (Cd, Cu, Pb and Zn) from oxidized waste rock amended with different alkaline by-products was studied during flooding. It has been argued that water covers for oxidized waste would significantly increase leaching through reductive dissolution of the pre-formed hydrous ferric oxides and the associated trace elements. After approximately three weeks pH in the reference had reached 2.5 and 3.3 in the pore and overlying water, respectively. This can be compared with pH from 6.1 (water works granules) to above 10 (lime kiln dust) in the amended systems. It is clear that the carbonate dominated alkaline by-products have lower pH than the oxide/hydroxide based by-products. However, the systems amended with carbonate based by-products have significantly higher alkalinity. Cadmium, Cu, Pb and Zn concentrations within the waste decreased with at least 99% compared to the reference. In most systems the surface waters can even be used as drinking water. Cadmium, copper and zinc concentrations are clearly related to pH with decreasing concentrations with increasing pH. Lead concentrations, on the other hand, decrease to pH 8, where the concentrations start to increase slightly again due to the formation of soluble Pb(OH)₃⁻ and Pb(OH)₄²⁻ species. The results indicate that flooding of oxidized waste rock amended with alkaline by-products can be used as a successful remediation technique.

  • 16.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Häller, Sara
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Geochemical processes in a historical alum shale dump, Kvarntorp2011In: Programme and Abstracts / [ed] Sarala P, Ojala VJ, Porsanger M-L, Vuorimiesyhdistys , 2011, p. 97, 6p CD-Rom-Conference paper (Refereed)
  • 17.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Multielement contamination at a skeet and trap shooting range: I: mobility assessment through sequential extractionManuscript (preprint) (Other academic)
  • 18.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Metal leachability and anthropogenic signal in roadside soils estimated from sequential extraction and stable lead isotopes2004In: Environmental Monitoring & Assessment, ISSN 0167-6369, E-ISSN 1573-2959, Vol. 90, no 1-3, p. 135-160Article in journal (Refereed)
    Abstract [en]

    Several roadside soil samples were collected at two field sites in Sweden. They were analysed for total elemental content (using both ICP-MS and XRF) and stable lead isotopes. Extraction with deicing salt solution and sequential extraction were performed in order to elucidate the potential mobility due to the use of deicing agents. The total concentrations of elements, especially lead, have decreased and lead is presently almost at background concentrations (15–51 ppm for surface samples). However, the isotopic signature indicates that old gasoline lead still is left at the site constructed prior to 1975. The field site constructed in 1992 showed, however, no 206Pb/207Pb ratio below 1.14. Only minor amounts were leached using deicing salt solutions; for lead only 0.29%, on average, was extracted indicating that the mobile fraction already was released. Sequential extraction indicated that lead mainly was associated with reducible (34.4%) and oxidisable (35.4%) fractions. Exchangable and acid soluble fractions contained 20.3% while 10.0% was found in the residual fraction. The salt extraction released, however, very low concentrations indicating that most in fraction 1 is acid soluble (e.g. carbonates). Tungsten was also found at high concentrations indicating a possible impact from studded tires. For tungsten the following composition was obtained: residual (48.0%) > oxidisable (47.6%) > reducible (3.3%) > exchangeable/acid soluble (1.1%). From the isotopic studies it was also suggested that the order for incorporating anthropogenic lead into soils is exchangeable/carbonates > (hydr)oxides > organic matter > residual. The multivariate technique principal component analysis (PCA) seems promising for evaluating large sequential extraction datasets.

  • 19.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Mobilisation of lead: field measurements at a trap range compared to solubility experiments2000Conference paper (Refereed)
  • 20.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Bäckman, Lars
    Folkeson, Lennart
    Lind, Bo
    Mobilisation of heavy metals by deicing salts in a roadside environment2004In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 38, no 3, p. 720-732Article in journal (Refereed)
    Abstract [en]

    The seasonal variations of some selected heavy metals (Cd, Cu, Pb and Zn) and principal anions in soil solutions were monitored as a function of distance from the road at two field sites in Sweden. During the winter, the conductivity, concentrations of dissolved sodium and chloride increased dramatically due to the application of deicing agents (i.e. NaCl). Due to ion exchange, the pH decreased one unit in the soil solutions, whereas the concentrations of total organic carbon decreased due to coagulation and/or sorption to stationary solids. The heavy metal concentrations increased during the winter, but through different mechanisms. Cadmium concentrations in the aqueous phase increased as a response to ion exchange, possibly also enhanced by the formation of chloride complexes. Similarly, the concentrations of zinc increased, due to ion exchange, with calcium and protons. The mechanisms of mobilisation for copper and lead were not that clear probably due to association with coagulated or sorbed organic matter in combination with colloid dispersion

  • 21.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Ekholm, David
    Evenhamre, Per
    Skogsjö, Erika
    Sediment quality before, during and after remediation of historical mine waste at Bersbo, Sweden2009In: Securing the Future and 8th ICARD, 2009, p. 11 pages-Conference paper (Refereed)
  • 22.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Lifvergren, Thomas
    Estimation of molecular weight distributions of humic substances in sediment pore waters: PLS modelling of field data2001In: 8th Nordic IHSS symposium on humic substances: characterisation, dynamics, transport and effects, Copenhagen: Royal Veterinary and Agricultural University , 2001, p. 17-21Conference paper (Refereed)
  • 23.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Mellberg, Karin
    Factors affecting the dissolution of lead pellets in natural watersManuscript (preprint) (Other academic)
  • 24.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Salih, Isam
    Pettersson, Håkan
    Chemical character of drinking water from Swedish crystaline bedrockManuscript (preprint) (Other academic)
  • 25.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Ulrika
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Hydrogeochemical interpretations of a fly ash/municipal sludge covered sulphidic mine waste deposit: a case study of alkaline leachates in an acidic environmentManuscript (Other academic)
  • 26.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Lifvergren, Thomas
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Migration and mobility of lead and antimony from a heavily polluted lake sedimentManuscript (preprint) (Other academic)
  • 27.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Nilsson, Ulrika
    Håkansson, Karsten
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Speciation of heavy metals in road runoff and roadside total deposition2003In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 147, no 1-4, p. 343-366Article in journal (Refereed)
    Abstract [en]

    The concentrations of Cd, Co, Cu, Pb, W and Zn were measured in road runoff and total deposition at two Swedish field sites during one year. It was found that the concentrations of most elements increased significantly during the winter, up to one order of magnitude. For cobalt and tungsten, it was found that around 90% of the total mass transport occurred during the winter, whereas for Cu, Pb, Cd, Zn and Na, the corresponding figures were 70–90, 40–80, 60–90, 50–70 and >99% depending on site specific conditions. The deicing salts (rock salts) did not significantly contribute to the increase in trace element concentrations. Instead, the increased concentrations were due to more intense wearing of the pavement during the winter because of the use of studded tires in combination with the chemical effects caused by the use of deicing salts. New potential elemental markers for roads and traffic are suggested.

  • 28.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Fly ash injection into weathered mine waste2013In: Annual International Mine Water Association Conference: Reliable Mine Water Technology / [ed] Brown, A.; Figueroa, L. & Wolkersdorfer, Ch., Colorado, USA: IMWA , 2013, p. 513-519Conference paper (Refereed)
    Abstract [en]

    By adding alkaline ashes through injection to weathered mine waste pH increased approximately 3 units, trace element was immobilized and flow rate decreased due to formation of hard pans. Reduction in trace element concentrations was around 96.9-99.6 % for copper, 94.7-99.7 % for zinc and 22.9-99.8 % for cadmium. For lead the best reduction was 97.3 % and the worst -393 % (increase). MSWI ashes performed worst with low buffering capacity and increase in vanadium and molybdenum concentrations.

  • 29.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Mixing of acid rock drainage with alkaline ash leachates: fate and immobilisation of trace elements2011In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 222, no 1-4, p. 377-389Article in journal (Refereed)
    Abstract [en]

    Acid rock drainage (ARD) from mine waste dumps often contains ferrous iron, sulphate and high concentrations of trace elements detrimental to the environment. Future costs will be enormous if the problem is not treated today. Simple, low maintenance, cost-effective methods for remediation of historical mine sites are therefore desired. In this study several mine waters were mixed with an alkaline ash leachtes in order to study the fate of the trace elements from both the mine waters (Cd, Cu, Pb, Zn, Ni and Co) and the ash leachates (Cr and Mo). It was found that the addition of ash water will precipitate hydrous ferric oxides (HFO) and hydrous aluminium oxides (HAO) and thereby inducing trace element sorption and co precipitation. It is also clear that the composition of the formed HFO/HAO mix determines the efficiency of the sorption for different trace elements. It is apparent that the amount of precipitating iron will determine the effectiveness of the removal of the trace elements. Sorption occurred much earlier (often one pH unit or more) in the system with high iron concentrations compared to the systems with lower iron concentrations. Removal of cadmium and zinc is difficult below pH 8 if the amount of precipitates is low. Using ash for generation of alkaline water may be a problem with regards to chromium and molybdenum. It is, however, possible to avoid problems with molybdenum by keeping the final pH around 7 and chromium(VI) from the ash water will be reduced into chromium(III) and precipitated as the hydroxide in the presence of iron(II) from the mine waters.

    The results imply that it is possible to also use fly ashes in alkaline leach beds in order to neutralize ARD followed by precipitation and sorption of trace elements.

  • 30.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Permanent under water storing of weathered mine waste after removal of fine fraction and addition of ash2014In: An Interdisciplinary Response to Mine Water Challenges / [ed] Sui, W., Sun, Y. & Wang, C., Xuzhou: China University of Mining and Technology Press , 2014, p. 711-714Conference paper (Refereed)
    Abstract [en]

    Weathered sulphidic mine waste is a major environmental problem. An experiment was performed in order to study water covers for oxidized mine waste. In two experiments oxidized mine waste were covered with water, in one experiment the fine fraction was removed and in one experiment alkaline ash was also added prior to water covering. It was found that removal of the fine fraction decreased pH and increased trace element concentrations. Water covering of the mine waste with and without ash decreased trace element concentrations indicating that co disposing oxidized sulphidic mine waste and ash under water might be a promising remediation method.

  • 31.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Stabilization of acid generating waste rock with fly ash: Immobilization of arsenic under alkaline conditions2010In: Mine water & innovative thinking: proceedings 2010 / [ed] Wolkersdorfer, C. and Freund, A., ovaScotia, Canada: Cape Breton University Press , 2010, p. 555-558Conference paper (Refereed)
    Abstract [en]

    A fly ash was used to increase pH and decrease arsenic leaching from an acidic mine waste.Both the amended system as well as the control system was leached with ultra pure water. pH in thecontrol increased from 1.7 to 2.7 at the end of the experiment while the pH in the amended systemdecreased from 12.6 to 11.5. compared to the control the initial concentrations of arsenic decreasedwith almost three orders of magnitude in the amended systems. A combination of co precipita-tion with iron and calcium arsenate precipitation were identified as the major arsenic immobi-lization mechanisms.

  • 32.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Uranium leaching from a burning black shale deposit: Present conditions and future scenarios2015In: Uranium – Past and Future Challenges: Proceedings of the 7th International Conference on Uranium Mining and Hydrogeology / [ed] Broder, J; Arab, Alireza, Springer Publishing Company, 2015, p. 47-54Conference paper (Refereed)
    Abstract [en]

    During WW2 oil was produced through pyrolysis of alum shale giving rise to waste that was deposited in the open pits and in a waste deposit. The waste deposit still today has significantly elevated temperatures (above 500 °C). Remaining pyrite in the waste material has also led to ARD with elevated trace metal concentrations. The waste deposit is no great environmental problem today but as soon as the waste pile cools off both the volumes of drainage and concentration of uranium will increase significantly.

  • 33.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kumla, Sweden.
    Use of multivariate statistics in order to understand the flow of acid rock drainage from an abandoned mining site2016In: Journal of Environmental Protection, ISSN 2152-2197, E-ISSN 2152-2219, Vol. 7, no 3, p. 358-371Article in journal (Refereed)
    Abstract [en]

    Pathways for acid rock drainage from an abandoned mining site (sulphidic ore) were investigated by analysing ground, seepage and surface waters. It was found that in affected ground and seepage waters pH was lower (average pH 5.0); sulphate higher (average 350 mg/L) and trace element concentrations were significantly increased (4330 μg/L copper and 7700 μg/L zinc) compared to surrounding waters. Multivariate statistics (principal component analysis) were used on the data set. Obtained loading plot showed a clear negative correlation between pH and parameters found at high concentrations, indicating that these parameters are found at the source term (acid rock drainage). Lead was also found in close proximity to iron and turbidity indicating that lead might be associated with particles. The score plot presented almost all samples from high concentrations to low concentrations along the first principal component (explaining 63% of the variation in the data set) indicating that dilution was an important mechanism for the decrease in concentrations as opposed to immobilisation on surfaces along the flowpath. Decrease in fluoride and sulphate along one of the suspected flowpath coincided with an increase in calcium. Through geochemical calculations it was concluded that calcite (CaCO3) dissolved along the flowpath and thus induced precipitation of gypsum (CaSO4) and fluorite (CaF2). Through a combination of PCA and geochemical calculations the most likely flowpaths for contaminated water from the abandoned mining site were presented, making it possible to prevent further negative effects on the surface water.

  • 34.
    Bäckström, Mattias
    et al.
    Örebro University, Department of Natural Sciences.
    Sartz, Lotta
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Multielement contamination at a skeet and trap shooting range: II: seasonal and spatial variations in surface and groundwatersManuscript (preprint) (Other academic)
  • 35.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Prevention of ARD through stabilization of waste rock with alkaline by-products: results from a meso-scale experiment2010In: Mina Water & Innovative Thinking: proceedings 2010 / [ed] Wolkersdorfer, C. & Freund, A, Nova Scotia, Canada: Cape Breton University Press , 2010, p. 559-563Conference paper (Refereed)
  • 36.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology.
    Larsson, Erik
    Bergskraft Bergslagen, Kopparberg, Sweden.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Properties of alkaline materials for injection into weathered mine waste piles: methods and initial pilot trials2011In: Mine water: managing the challenges: proceedings of the International Mine Water Association Congress 2011 / [ed] Rüde, Thomas R.; Freund, Antje; Wolkersdorfer, Christian, Aachen: RWTH , 2011, p. 265-269Conference paper (Refereed)
    Abstract [en]

    Several alkaline materials were studied with regards to their ability to form stable suspensions withwater. Gravitational injection of alkaline materials were performed into weathered mine waste in two differentpilot scales (25 L and 1 000 L). When water was added after injection lime mud (LM) was flushed out whilelime kiln dust (LKD) and green liqour (GLD) remained within the mine waste. Deconstruction of the pilot sys-tems showed that both materials had penetrated the voids present. LKD and GLD increased pH significantlyand reduced trace metal concentratios. It is concluded that both LKD and GLD are suitable for stabilizing acidgenerating mine waste.

  • 37.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sädbom, Stefan
    Risk assessment of historical mine waste using chemical analysis and ocular mineral/rock classification: a comparison2008In: ICAM 2008: 9th International Congress for Applied Mineralogy, 2008, p. 85-90Conference paper (Refereed)
  • 38.
    Bäckström, Mattias
    et al.
    Örebro University, School of Science and Technology.
    Sädbom, Stefan
    Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Suggestion for a protocol for detailed investigation of historical mine sites2012In: 9th International Conference on Acid Rock Drainage (ICARD 2012) / [ed] Price, W.A., Hogan, C. and Tremblay, G., Red Hook, NY: Curran Associates, Inc., 2012, p. 1340-1350Conference paper (Refereed)
    Abstract [en]

    A protocol for detailed investigation of mine sites is suggested. Results from the investigation are important when planning mine site reclamation. Initially, the mine site is divided into several sub sites according to topography. For general appearance the following parameters were developed and estimated directly in the field for every sub site:

    (1) shape, (2) historical land use, (3) amount of waste rock, (4) weathering, (5) waste rock size, (6) carbonates and silicates, (7) vegetation cover, (8) low and high species, (9) moss and grass/herbs, (10) broad-leaf and coniferous, (11) spruce and pine, (12) birch and aspen, and (13) blueberries and lingonberries. Every parameter was designated a numerical value between 0 and 5. After sampling ocular mineral/rock classification was performed on composite samples from every sub site and the following major components were determined: (14) silicate, (15) mica, (16) granite/pegmatite, (17) carbonates, (18) iron oxide ore and (19) sulphide ore. In addition the relative distribution between the different sulphide minerals was also determined: (20) chalcopyrite vs sphalerite; (21) galena vs sphalerite; (22) chalcopyrite vs galena and (23) pyrite vs pyrrhotite.

    Results from a historical mine site in Kopparberg, Sweden, are used to illustrate the methodology

  • 39. Dahlén, Johan
    et al.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Ephraim, James
    Borén, Hans
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Determination of the molecular weight of fulvic acids by UV/VIS spectroscopy1999In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 38, no 4, p. 783-794Article in journal (Refereed)
    Abstract [en]

    Partial least squares (PLS) modeling was applied to investigate number-average molecular weights (Mn) and weight-average molecular weights (Mw) of fulvic acids (FAs) in relation to the corresponding UVNIS spectra. The Mn and Mw values were determined by size exclusion chromatography (SEC). The impact of pH control, wavelength range and density as well as smoothing and derivation of spectra were tested. It was found that PLS models based on absorbance spectra can be a fast and powerful complement to existing techniques employed for determination of molecular weights of FAs. Control of pH of the FA solutions is important for the performance of the models. The models were also compared with the best univariate alternatives.

  • 40. Dahlén, Johan
    et al.
    Karlsson, Stefan
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Hagberg, Jessika
    Örebro University, Department of Natural Sciences.
    Pettersson, Håkan
    Determination of nitrate and other water quality parameters in groundwater from UV/Vis spectra employing partial least squares regression2000In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 40, no 1, p. 71-77Article in journal (Refereed)
    Abstract [en]

    The use of UV/Vis spectroscopy in combination with partial least squares (PLS) regression for the simultaneous prediction of nitrate and non-purgeable organic carbon (NPOC) in groundwaters was evaluated. A model of high quality was obtained using first order derivative spectra in the range 200–300 nm. Inclusion of non-UV-absorbing constituents in the modeling procedure, i.e., chloride, sulfate, fluoride, total carbon (TC), inorganic carbon (IC), alkalinity, pH and conductivity was also evaluated. This model seemed to be useful for prediction of chloride, TC, IC, alkalinity and conductivity, while its ability to predict sulfate, fluoride and pH was poor. In conclusion, application of PLS regression, which requires neither filtration of samples nor addition of chemicals, is a promising alternative for fast interpretation of geochemical patterns of groundwater quality.

  • 41.
    Fahlqvist, Linnea
    et al.
    Örebro University, School of Science and Technology. Bergskraft Bergslagen, Kopparberg, Sweden.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Removal of uranium from a neutral mine water using uncoated and iron oxyhydroxide coated iron tailings2013In: Annual International Mine Water Association Conference: Reliable Mine Water Technology / [ed] Brown, A.; Figueroa, L. & Wolkersdorfer, Ch., Colorado, USA: IMWA , 2013, p. 551-557Conference paper (Refereed)
  • 42.
    Fahlqvist, Linnea
    et al.
    Örebro University, School of Science and Technology.
    Sartz, Lotta
    Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Bäckström, Mattias
    Örebro University, School of Science and Technology. Bergskraft Bergslagen AB, Kopparberg, Sweden.
    Removal of zinc and lead from a neutral mine water using iron tailings and iron oxyhydroxide coated iron tailings2012In: Mine Water and the Environment / [ed] McCullough, C.D., Lund, M.A. and Wyse, L., International Mine Water Association (IMWA) , 2012, p. 584A-584GConference paper (Refereed)
  • 43. Gustafsson, Jon Petter
    et al.
    Dässman, Ellinor
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Towards a consistent geochemical model for prediction of uranium(VI) removal from groundwater by ferrihydrite2009In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 24, no 3, p. 454-462Article in journal (Refereed)
    Abstract [en]

    Uranium(VI), which is often elevated in granitoidic groundwaters, is known to adsorb strongly to Fe (hydr)oxides under certain conditions. This process can be used in water treatment to remove U(VI). To develop a consistent geochemical model for U(VI) adsorption to ferrihydrite, batch experiments were performed and previous data sets reviewed to optimize a set of surface complexation constants using the 3-plane CD-MUSIC model. To consider the effect of dissolved organic matter (DOM) on U(VI) speciation, new parameters for the Stockholm Humic Model (SHM) were optimized using previously published data. The model, which was constrained from available X-ray absorption fine structure (EXAFS) spectroscopy evidence, fitted the data well when the surface sites were divided into low- and high-affinity binding sites. Application of the model concept to other published data sets revealed differences in the reactivity of different ferrihydrites towards U(VI). Use of the optimized SHM parameters for U(VI)-DOM complexation showed that this process is important for U(VI) speciation at low pH. However in neutral to alkaline waters with substantial carbonate present, Ca–U–CO3 complexes predominate. The calibrated geochemical model was used to simulate U(VI) adsorption to ferrihydrite for a hypothetical groundwater in the presence of several competitive ions. The results showed that U(VI) adsorption was strong between pH 5 and 8. Also near the calcite saturation limit, where U(VI) adsorption was weakest according to the model, the adsorption percentage was predicted to be >80%. Hence U(VI) adsorption to ferrihydrite-containing sorbents may be used as a method to bring down U(VI) concentrations to acceptable levels in groundwater.

  • 44.
    Henriksson, Sara
    et al.
    Örebro University, School of Science and Technology.
    Hagberg, Jessika
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Persson, I.
    Lindström, Gunilla
    Örebro University, School of Science and Technology.
    Assessment of PCDD/Fs levels in soil at a contaminated sawmill site in Sweden: a GIS and PCA approach to interpret the contamination pattern and distribution2013In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 180, p. 19-26Article in journal (Refereed)
    Abstract [en]

    Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzo-p-furans (PCDD/Fs) were analysed in soil from a Swedish sawmill site where chlorophenols (CPs) had been used more than 40 years ago. The most contaminated area at the site was the preservation subarea where the PCDD/F WHO2005-TEQ level was 3450 times higher than the current Swedish guideline value of 200 ng TEQ/kg soil for land for industrial use. It was also shown that a fire which destroyed the sawmill might have affected the congener distribution at the concerned areas. To get a broader picture of the contamination both GIS (spatial interpolation analysis) and multivariate data analysis (PCA) were applied to visualize and compare PCDD/F levels as well as congener distributions at different areas at the site. It is shown that GIS and PCA are powerful tools in decisions on future investigations, risk assessments and remediation of contaminated sites.

  • 45.
    Karlsson, Lovisa
    et al.
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Leaching of sulfidic alum shale waste at different temperatures2012In: 9th International Conference on Acid Rock Drainage (ICARD 2012) / [ed] Price, W.A., Hogan, C. and Tremblay, G., Red Hook, NY: Curran Associates, Inc., 2012, p. 1015-1025Conference paper (Refereed)
    Abstract [en]

    Four different alum shale waste products (unprocessed shale, weathered fines, processed shale and shale ash) from Kvarntorp, Sweden, were leached at different temperatures (-18°C, +22°C and +70°C) in order to elucidate the influence from freezing (frost wedging) and high temperatures (heat generated during sulfide oxidation). Unprocessed shale and the weathered fine fraction have an acidic pH while the processed shale and the shale ash have circum neutral pH. Leaching was performed at liquid solid ratio of 10:1 at room temperature followed by treatment at different temperatures for 24 hours (cycle repeated 10 times). pH, electrical conductivity, redox, alkalinity, acidity, sulfate, major cat ions and trace elements were measured. pH was almost one pH unit lower in the heat treated shale ash samples compared to the samples kept in the freezer. No significant pH differences were observed for the other samples. Iron and sulfate concentrations were found to be higher in the heat treated samples still containing pyrite (unprocessed shale and weathered fines) indicating a higher rate of oxidation. When it comes to trace elements molybdenum, for instance, significantly higher concentrations were leached from the processed shale compared to the unprocessed shale indicating increased leachability due to transformation of the primary minerals

  • 46.
    Karlsson, Lovisa
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Sjöberg, Viktor
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Release of metals from unprocessed and processed black shale due to natural weathering2013In: Annual International Mine Water Association Conference: Reliable Mine Water Technology / [ed] Adrian Brown, Linda Figueroa, Christian Wolkersdorfer, Colorado, USA: IMWA , 2013, p. 391-397Conference paper (Refereed)
    Abstract [en]

    Black shale was mined and processed for recovery of hydrocarbons in Kvarntorp, some 200 km SW of Stockholm, Sweden, during 1942–66. Remains from the mining period is a deposit with 40 Mm³ of crushed shale residues: Unprocessed 3ne-grained shale as well as processed shale. The deposit is still hot; oxidation of sulphides as well as burning of hydrocarbons are still in progress some 50 years a1er closure. Weathering of the shale leads to releases of metal-rich leachates which will increase with time. The release of metals from pristine shale as well as weathered shale (exposed to the atmosphere for 50 years) and two di2erent processed shale residues have been studied using water of di2erent pH as leaching solution, to simulate extreme pH-variations in environmental waters: 3.0 (determined by oxidation of iron sulphides), 5.5 (bu2ered by carbon dioxide), 8.5 (bu2ered by calcite) and 12.5 (bu2ered by calcium hydroxide). Extraction of cationic elements was substantial (several percent of the total content) for Ca and Mg, as well as Ni, Co and U at pH 3, and very high (up to 50–60 %) for anionic elements (V, Mo, As) at pH 12.5. Especially the high-temperature processed shale would be a potential source for As and Mo at high pH. The pH-dependence of the weathering processes should be considered when future remediation (or metal recovery) processes and strategies are designed.

  • 47.
    Karlsson, Stefan
    et al.
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Changes in hydrochemistry some 15 years after covering of sulphidic mine waste, Bersbo, Sweden2005In: Securing the future: international conference on mining and the environment, metals and energy recovery : proceedings, 2005, p. 509-518Conference paper (Refereed)
  • 48.
    Karlsson, Stefan
    et al.
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Bäckström, Mattias
    Örebro University, School of Science and Technology.
    Weathering mechanisms and composition of effluents from a sulphide mine waste deposit after covering: twenty years of field data2010In: Mine water and innovative thinking: proceedings 2010 / [ed] Christian Wolkersdorfer, Antje Freund, Nova Scotia, Canada: Cape Breton, University Press , 2010, p. 359-362Conference paper (Refereed)
    Abstract [en]

    In 1988 a deposit with some 500,000 m³ of coarse sulphidic mine waste at Bersbo, Sweden, was covered with compacted illitic clay or cement stabilised coal fly-ash (CeFill) to prevent  eathering and the transport of metals. Theoretically, oxidation of pyrite would give a sulphate/iron ratio in solution exceeding 2, if oxygen is the electron acceptor, but below 2 if Fe(III) is the oxidizing agent. The effluents had ratios of 35—50 and 2—0.8 before and after covering, respectively, why it is concluded that weathering continued. The altered hydrological regime contributes to changes in metal concentrations in the surrounding surface water.

  • 49.
    Karlsson, Stefan
    et al.
    Örebro University, Department of Natural Sciences.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Surface water quality in Bersbo, Sweden: fifteen years after amelioration of sulphidic waste2003Conference paper (Refereed)
  • 50.
    Karlsson, Stefan
    et al.
    Örebro University, Department of Natural Sciences.
    Grahn, Evastina
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Bäckström, Mattias
    Örebro University, Department of Natural Sciences.
    Historical pollution of seldom monitored trace elements in Sweden - Part A: sediment properties and chronological indicators2006In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 8, no 7, p. 721-731Article in journal (Refereed)
    Abstract [en]

    Sediment cores from four small oligotrophic boreal lakes, with minor acidification, in remote regions of central Sweden were used for historical interpretation of their metal content, with focus on Cu, Cd, Pb and Zn in Lake Stensjön, which has the longest sediment record (at least two centuries according to 210Pb dating). Comparison is made with the other three lakes. Major and trace elements in lake water, porewater and the acid-leached (HNO3) solid sediment phase was analysed with ICP-MS. In addition, general lake water chemistry, TOC and principal anions were measured in the aqueous phases. Redistribution processes were interpreted from geochemical modelling. The solid/solution distribution of pe/pH sensitive elements, indicates a minor diagenetic redistribution and the concentration profiles are therefore suitable for chronological evaluation. The ratios of Al, Ti, Sc and V, indicated a qualitative shift of sedimenting material a century ago, which did not have any impact on the retention of trace elements. Lead had a concentration profile, supported by the 206Pb/207Pb ratio, where it was possible to distinguish preindustrial conditions, early industrialisation in Europe, industrialisation in Sweden, and the use of leaded petrol after the Second World War. Cadmium showed a similar concentration pattern. The zinc profile resembled that of cadmium, but with less enrichment. Local lithogenic sources are believed to be quantitatively important. The solid/solution distribution (Kd) was independent of depth for all four elements. The sediment concentrations of copper and zinc are not related to early industrialisation but its concentration has doubled since the Second World War.

12 1 - 50 of 95
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