umu.sePublications
Change search
Refine search result
1 - 42 of 42
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Andersson, Tove
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    Giesler, Reiner
    Ecology and Environmental Science.
    Adsorption of Monomethyl Phosphate to the Goethite (-FeOOH)/water Interface2002Conference paper (Other academic)
  • 2.
    Bengtsson, Åsa
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    A comparative study of the dissolution of hydroxyapatite and fluorapatite in the absence and presence of organic ligands2005In: GEOCHIMICA ET COSMOCHIMICA ACTA 69 (10): A68-A68 Suppl. S, MAY 2005, ISSN 0016-7037, Vol. 69, no 10, p. A68-Article in journal (Other academic)
  • 3.
    Bengtsson, Åsa
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Chemistry.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    A kinetic and spectroscopic study of fluorapatite dissolution2004Conference paper (Other academic)
  • 4.
    Dopson, Mark
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Boström, Dan
    Umeå University, Faculty of Science and Technology, Department of Applied Physics and Electronics, Energy Technology and Thermal Process Chemistry.
    Silicate mineral dissolution in the presence of acidophilic microorganisms: implications for heap bioleaching2009In: Hydrometallurgy, ISSN 0304-386X, E-ISSN 1879-1158, Vol. 96, no 4, p. 288-293Article in journal (Refereed)
    Abstract [en]

    Silicate minerals are found with sulfide minerals and therefore, can be present during heap bioleaching for metal extraction. The weathering of silicate minerals by chemical and biological means is variable depending on the conditions and microorganisms tested. In low pH metal rich environments their dissolution can influence the solution chemistry by increasing pH, releasing toxic trace elements, and thickening of the leach liquor. The amenity of five silicate minerals to chemical and biological dissolution was tested in the presence of either ‘Ferroplasma acidarmanus’ Fer1 or Acidithiobacillus ferrooxidans with olivine and hornblende being the most and least amenable, respectively. A number of the silicates caused the pH of the leach liquor to increase including augite, biotite, hornblende, and olivine. For the silicate mineral olivine, the factors affecting magnesium dissolution included addition of microorganisms and Fe2+. XRD analysis identified secondary minerals in several of the experiments including jarosite from augite and hornblende when the medium contained Fe2+. Despite acidophiles preferentially attaching to sulfide minerals, the increase in iron coupled with very low Fe2+ concentrations present at the end of leaching during dissolution of biotite, olivine, hornblende, and microcline suggested that these minerals supported growth. Weathering of the tested silicates would affect heap bioleaching by increasing the pH with olivine, fluoride release from biotite, and production of jarosite during augite and hornblende dissolution that may have caused passivation. These data have increased knowledge of silicate weathering under bioleaching conditions and provided insights into the effects on solution chemistry during heap bioleaching.

  • 5. Dopson, Mark
    et al.
    Ossandon, Francisco J.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Holmes, David S.
    Metal resistance or tolerance?: Acidophiles confront high metal loads via both abiotic and biotic mechanisms2014In: Frontiers in Microbiology, ISSN 1664-302X, E-ISSN 1664-302X, Vol. 5, p. 157-Article in journal (Refereed)
    Abstract [en]

    All metals are toxic at high concentrations and consequently their intracellular concentrations must be regulated. Extremely acidophilic microorganisms have an optimum growth of pH <3 and proliferate in natural and anthropogenic low pH environments. Some acidophiles are involved in the catalysis of sulfide mineral dissolution, resulting in high concentrations of metals in solution. Acidophiles are often described as highly metal resistant via mechanisms such as multiple and/or more efficient active resistance systems than are present in neutrophiles. However, this is not the case for all acidophiles and we contend that their growth in high metal concentrations is partially due to an intrinsic tolerance as a consequence of the environment in which they live. In this perspective, we highlight metal tolerance via complexation of free metals by sulfate ions and passive tolerance to metal influx via an internal positive cytoplasmic transmembrane potential. These tolerance mechanisms have been largely ignored in past studies of acidophile growth in the presence of metals and should be taken into account.

  • 6.
    Giesler, Reiner
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Andersson, Tove
    Chemistry.
    Lövgren, Lars
    Chemistry.
    Phosphate adsorption in aluminum and iron rich humus soils from forested groundwater discharge areas2000Conference paper (Other academic)
  • 7.
    Giesler, Reiner
    et al.
    Umeå University, Faculty of Science and Technology, Ecology and Environmental Science.
    Andersson, Tove
    Chemistry.
    Lövgren, Lars
    Chemistry.
    Persson, Per
    Chemistry.
    Phosphate sorption in aluminum- and iron-rich humus soils2005In: Soil Science Society of America Journal, Vol. 69, no 1, p. 77-86Article in journal (Refereed)
    Abstract [en]

    Groundwater discharge areas in boreal forest ecosystems can potentially be areas where Fe and Al accumulate in the forest floor and affect the solubility of P. This study was conducted to determine phosphate sorption properties using humus soils containing high native amounts of Al and Fe. Humus soils were collected from two different forested groundwater discharge areas varying in pH and amount and distribution of At and Fe species. The phosphate sorption capacities were 265 and 216 mmol P kg(-1) dry wt. soil, respectively, for the two humus soils. Pyrophosphate extractable Al and Fe dominated in the first soil, 738 mmol kg(-1) dry wt. The concentration of pyrophosphate extractable Al and Fe in the second soil was 317 mmol kg(-1) dry wt.. whereas citrate-dithionite (CD) extracted 548 mmol Al and Fe kg(-1) dry wt. Using 0.1 mol dm(-3) NaCl as ionic medium gave a higher phosphate sorption compared with deionized water at the midrange additions, but no difference at the highest addition. Phosphate sorption was pH independent when 0.1 mol dm(-3) NaCl was used, whereas deionized water gave a sorption minimum at approximately pH 6. Dissolved organic carbon (DOC) release in solution was positively correlated with phosphate sorption, especially in 0.1 mol dm(-3) NaCl ionic medium. However, dissolved organic P (DOP) was unaffected by the phosphate sorption. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) indicated that precipitation of Al and Fe phosphates dominated at higher phosphate additions in the soil with mainly organically bound At and Fe, whereas both surface sorption and precipitation occurs in the soil with a larger amount of CD-extractable Fe.

  • 8. Jacks, G
    et al.
    Lövgren, LarsUmeå University, Faculty of Science and Technology, Chemistry.Löfgren, OMiskovsky, K
    Study of the chemical and ecological state of Lake Hornträsket, Mining district of Kristineberg, Northern Sweden2005Conference proceedings (editor) (Refereed)
  • 9. Jönson, J
    et al.
    Lövgren, LarsUmeå University, Faculty of Science and Technology, Chemistry.
    Attenuation of metals by sorption to secondary iron precipitates2001Conference proceedings (editor) (Refereed)
  • 10. Jönson, J
    et al.
    Lövgren, LarsUmeå University, Faculty of Science and Technology, Chemistry.
    Sorption properties of secondary iron precipitates in oxidozed mining waste2000Conference proceedings (editor) (Refereed)
  • 11. Jönsson, Jörgen
    et al.
    Jönsson, Julia
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Precipitation of secondary Fe(III) minerals from acid mine drainage2006In: Applied Geochemistry, Vol. 21, p. 437-45Article in journal (Refereed)
    Abstract [en]

    Oxidation of FeS2 in mine waste releases Click to view the MathML source, Fe(II) and H+, resulting in acid mine drainage (AMD). Subsequent oxidation and precipitation of Fe produces different Fe(III) phases where the mineralogical composition depends on pH and the ambient concentrations of metal ions and complexing ligands. The oxidation and precipitation of Fe in AMD has been studied under various conditions with the intent of understanding the role these processes play in the natural attenuation of metal contaminants in the AMD. The combined process of Fe oxidation and precipitation in AMD from the Kristineberg mine, northern Sweden, has been investigated with pH-stat experiments at pH 5.5 and 7 at 10 and 25 °C. The precipitates formed have been characterised in terms of mineralogy and surface area. Similar phases formed at both temperatures, while the oxidation and precipitation occurred more readily at the higher temperature and higher pH. At pH 7, mainly lepidocrocite (γ-FeOOH) was precipitated while at a lower pH of 5.5, a mixture of schwertmannite, goethite, ferrihydrite and lepidocrocite formed. The ambient Zn(II) concentration was immediately reduced to acceptable levels (according to Swedish EPA) at pH 7 whereas a 2–3 weeks ageing period was necessary to achieve the same effect at pH 5.5. The presence of natural organic matter (NOM) reduced the attenuating effect at pH 5.5 after ageing but increased it slightly at pH 7. Addition of Zn(II) at pH 8 resulted in a mixed Fe(III)–Zn(II) precipitate of unknown composition with some Zn(II) adsorbed at the surface. The Fe(III) precipitates formed are potentially useful for the natural attenuation of metal contaminants in AMD although based on these investigations, the degree of success depends upon pH and NOM concentration.

  • 12.
    Jönsson, Jörgen
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Complexation of Metal Ions to Secondary Iron Oxides from Mining Waste2002Conference paper (Other academic)
  • 13.
    Jönsson, Jörgen
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Schwertmannite precipitated from acid mine drainage: phase transformation, sulphate release and surface properties2005In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 20, no 1, p. 179-191Article in journal (Refereed)
    Abstract [en]

    Schwertmannite precipitated from acid mine drainage at the Kristineberg Zn-Cu mine in northern Sweden has been characterised regarding elemental composition, phase transformation as a function of pH and time. SO42- release and speciation of SO42- associated with the solid. The elemental analysis gave the composition FeSOS(OH)(5.02)(-SO4)(1.49) . 0.5H(2)O where approximately 1/3 of the SO42- is adsorbed to the surface. The conversion of schwertmannite to goethite at pH 9 was complete within 187 days; at pH 6. the conversion was still incomplete after 514 days. Lower pH and relatively high SO42- concentration decreased the conversion even further. Also temperature was shown to be an important parameter for this process and low temperature (+4 degreesC) effectively stopped the transformation at pH 3. The release of SO42- was linear with pH and X-ray photoelectron spectroscopy measurements confirming that the surface bound SO42- was released before bulk SO42-. Zeta potential measurements indicate a pH(IEP) of 7.2 for the schwertmannite sample. Prior to conversion into goethite, the SO42- associated with schwertmannite was indicated by attenuated total reflectance FTIR spectroscopy to be present both as bulk and surface species. Furthermore: the speciation of surface SO42- was shown to vary with pH and two predominating species were detected. As pH increases. SO42- is increasingly Coordinated in an outer sphere mode whereas a stronger. possibly inner sphere, complex dominates. at low pH.

  • 14.
    Jönsson, Jörgen
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Adsorption of Cu(II) to schwertmannite and goethite in presence of dissolved organic matter2006In: Water Research, ISSN 0043-1354, Vol. 40, no 5, p. 969-74Article in journal (Refereed)
    Abstract [en]

    Sorption processes involving secondary iron minerals may significantly contribute to immobilisation of metals in soils and surface waters. In the present work the effect of dissolved organic matter (DOM) from a concentrated bog-water on the adsorption of Cu(II) onto schwertmannite (Fe8O8(OH)6SO4) and goethite (alpha-FeOOH) has been studied. The acid/ base behaviour of DOM up to pH 6 was explained by assuming a diprotic acid with a density of carboxylate groups of 6.90 microeq (mg C)(-1). The resulting acidity constants, recalculated to zero ionic strength were pK(0)a1 = 3.61 and pK(0)a2 = 5.34. The uptake of DOM to schwertmannite and goethite was highest at low pH although adsorption was significant also under mildly alkaline conditions. Adsorption to the two minerals was similar although at high pH more DOM was adsorbed to schwertmannite than to goethite. DOM enhanced the adsorption of Cu(II) at moderately low pH in the goethite system but there was no effect of DOM in the case of schwertmannite. The presence of Cu(II) resulted in a decreased adsorption of DOM to goethite at weakly acidic pH and increased adsorption at high pH. In the case of schwertmannite, Cu(II) did not affect DOM uptake.

  • 15.
    Kozyatnyk, Ivan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gustafsson, A.
    MoRe Research AB, Örnsköldsvik, Sweden.
    Törneman, Niklas
    SWECO, Malmö, Sweden.
    Evaluation of barrier materials for removing pollutants from groundwater rich in natural organic matter2014In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 70, no 1, p. 32-39Article in journal (Refereed)
    Abstract [en]

    Permeable barriers are used for passive remediation of groundwater and can be constructed from a range of materials. The optimal material depends on the types of contaminants and physicochemical parameters present at the site, as well as the hydraulic conductivity, environmental safety, availability, cost and long-term stability of the material itself. The aim of the presented study was to test a number of materials for their ability to remove heavy metals and organic pollutants from groundwater with a high (140 mg L-1) content of natural organic matter (NOM). The following materials were included in the study: sand, peat, fly ash, iron powder, lignin and combinations thereof. Polluted water was fed into glass columns loaded with each sorbent and the contaminant removal efficiency of the material was evaluated through chemical analysis of the percolate. Materials based on fly ash and zero-valent iron were found to be the most effective for heavy metal removal, while fly ash and peat were the most effective for removing aliphatic compounds. Filtration through lignin and peat led to leaching of NOM. Although the leaching decreased over time, it remained high throughout the experiments. The results indicate that remediation of contaminated land at disused industrial sites is a complex task that often requires the use of mixed materials or a minimum of two sequential barriers.

  • 16.
    Kozyatnyk, Ivan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Peter, Haglund
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    On the leaching of mercury by brackish seawater from permeable barriers materials and soil2015In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 3, no 2, p. 1200-1206Article in journal (Refereed)
    Abstract [en]

    Soils at former pulp, paper and chemical plants in the subarctic (boreal) zone, including Canada, Scandinavia, Russia, and parts of the USA, are often contaminated with organic pollutants and heavy metals, of which mercury is one. The soil- and ground-water at these sites is often rich in dissolved organic matter (DOM), particularly fulvic substances. Permeable barriers are sometimes used to limit the migration of pollutants with groundwater and protect nearby aquatic environments. These are installed downstream of the source, generally close to the receiving water body. In cases when such barriers have been installed close to the sea, concerns have been raised that the seawater may back-flush the barrier and release mercury, often a key contaminant, in the form of stable chloride complexes.

    Intrusion of seawater into coastal groundwater reservoirs has previously been shown to result in dissolution of mercury from soil. Less is known about the ability of brackish water, present in estuaries or brackish seas, to mobilize mercury from soil or from barrier materials. We therefore investigated the effect of artificial brackish seawater (6.3‰ salinity) on the sorption and desorption of mercury from different barrier materials (activated carbon, fly ash, lignite, torrified material, peat, and iron powder).

    The mercury was found to be associated with the high molecular weight fraction of groundwater DOM and it was concluded that the mercury was removed (sorbed) as relatively strong DOM-complexes. Chloride ions did not seem to form aqueous complexes with mercury to any great extent and artificial brackish seawater did not desorb mercury from the contaminated soil or from the studied barrier materials.

  • 17.
    Kozyatnyk, Ivan
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Multivariate assessment of barriers materials for treatment of complex groundwater rich in dissolved organic matter and organic and inorganic contaminants2017In: Journal of Environmental Chemical Engineering, ISSN 2160-6544, E-ISSN 2213-3437, Vol. 5, no 4, p. 3075-3082Article in journal (Refereed)
    Abstract [en]

    This study focused on the challenges of treating groundwater rich in dissolved organic matter and contains both heavy metals and organic pollutants. Activated carbon, fly ash, lignite, peat, torrefied organic material and zero-valent iron were tested as prospective materials for permeable barriers. Removal of different pollutants was analyzed using coefficients of the Freundlich equation for adsorption isotherms. Principal components analysis was used to visualize similarities and differences in pollutant removal efficiency and sorbent capacity between barrier materials. Fly ash, iron (aerobic conditions) and activated carbon were found to be promising materials for dissolved organic matter removal. Fly ash was the most effective material for metal removal, and fly ash, activated carbon and peat were the most effective materials for removal of organic contaminants. Thus, fly ash shows the most potential for simultaneous removal of metals and organic pollutants. However, it has limited capacity for removing neutral halogenated aromatic compounds. For these, zero-valent iron (aerobic conditions) has greater capacity, probably because of the formation of a porous layer of iron oxyhydroxide. In summary, batch adsorption experiments followed by principal components analysis evaluation of the results are useful tools for selecting suitable materials for treatment of groundwater contaminated with multiple organic and inorganic pollutants.

  • 18.
    Kumpiene, Jurate
    et al.
    Division of Waste Science and Technology, Luleå University of Technology, SE- 97187 Luleå, Sweden.
    Ragnvaldsson, Daniel
    Swedish Defence Research Agency, Umeå, Sweden.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tesfalidet, Solomon
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gustavsson, Björn
    Division of Waste Science and Technology, Luleå University of Technology, SE- 97187 Luleå, Sweden.
    Lättström, Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Leffler, Per
    Swedish Defence Research Agency, Umeå, Sweden.
    Maurice, Christian
    Ramböll Sweden, SE-971 26 Luleå, Sweden.
    Impact of water saturation level on arsenic and metal mobility in the Fe-amended soil2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 74, no 2, p. 206-215Article in journal (Refereed)
    Abstract [en]

    The impact of water saturation level (oxidizing-reducing environment) on As and metal solubility in chromium, copper, arsenic (CCA)-contaminated soil amended with Fe-containing materials was studied. The soil was mixed with 0.1 and 1 wt% of iron grit (Fe(0)) and 1, 7 and 15 wt% of oxygen scarfing granulate (OSG, a by-product of steel processing). Solubility of As and metals was evaluated by a batch leaching test and analysis of soil pore water. Soil saturation with water greatly increased As solubility in the untreated as well as in the Fe-amended soil. This was related to the reductive dissolution of Fe oxides and increased concentration of As(III) species. Fe amendments showed As reducing capacity under both oxic and anoxic conditions. The cytotoxicity of the soil pore water correlated with the concentration of As(III). The Fe-treatments as well as water saturation of soil were less significant for the solubility of Cu, Cr and Zn than for As. The batch leaching test used for waste characterization substantially underestimated As solubility that could occur under water-saturated (anaerobic) conditions. In the case of soil landfilling, other techniques than Fe-stabilization of As containing soil should be considered.

  • 19. Köhler, S
    et al.
    Hruska, J
    Jönsson, Jörgen
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lofts, S
    Evaluation of different approaches to quantify strong organic acidity and acid-base buffering of organic-rich surface waters in Sweden2002In: Water Research, Volume, Vol. 36, no 18, p. 4487-96Article in journal (Refereed)
    Abstract [en]

    The role of organic acids in buffering pH in surface waters has been studied using a small brownwater stream (26mgL-1 TOC) draining a forested catchment in Northern Sweden. Under the conditions of elevated pressure of CO2 stream field pH was changed between 3.5 and 6.1 during the acidification and alkalinization experiment. Acid-base characteristics of the natural organic matter were also determined using a high precision potentiometric method for a concentrated sample from the same stream. We compared the predictions from the Windermere Humic Aqueous Model (WHAM Model V), a model derived from the potentiometric titration (diprotic/monoprotic acid model) and a previously derived triprotic acid model which only uses alkalinity and TOC as input variables. The predicted buffering characteristics of all three models are very similar in the pH range 4.5-7 which suggests that during routine analysis alkalinity and TOC are sufficient to give a good estimate of organic acid anion charge contribution in a large range of surface waters. A slightly adjusted version of WHAM V successfully describes the organic charge contribution in a large number of sampled surface water lakes, which were previously used to calibrate the triprotic model.

  • 20. Löfgren, Ola
    et al.
    Lövgren, LarsUmeå University, Faculty of Science and Technology, Department of Chemistry.Miskovsky, KarelFilipsson, MagnusJacks, GunnarTapper, Mats
    Amendment of the Unsaturated Zone of a Sulphide Containing Cover Applied During Remediation of the Hornträsk Cu-Zn Mine, North Sweden2009Conference proceedings (editor) (Other academic)
    Abstract [en]

    

  • 21.
    Lövgren, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Jönsson, Jörgen
    Umeå University, Faculty of Science and Technology, Chemistry.
    Adsorption of metal ions to secondary iron oxides from mine waste2003Conference paper (Other academic)
  • 22.
    Lövgren, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Jönsson, Jörgen
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sorption properties and phase transformation of schwertmannite preciptated from mining waste leachates2003Conference paper (Other academic)
  • 23.
    Lövgren, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Widerlund, A
    Öhlander, B
    Kristineberg spearheads research into safe disposal of mine waste2007Other (Other (popular science, discussion, etc.))
  • 24.
    Lövgren, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Öhlander, B
    Neretnieks, I
    Moreno, L
    Malmström, M
    Elander, P
    Lindvall, M
    Lindström, B
    MiMi - Performance Assessment Main Report2003Report (Other (popular science, discussion, etc.))
  • 25. Lützenkirchen, Johannes
    et al.
    Boily, Jean-François
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Limitations of the potentiometric titration technique in determining the proton active site density of goethite surfaces2002In: Geochimica et Cosmochimica Acta: Volume 66, Issue 19, 1 October 2002, Pages, Vol. 66, no 19, p. 3389-96Article in journal (Refereed)
    Abstract [en]

    Density of proton active surface sites at mineral surfaces is a property of fundamental importance in equilibrium modeling of surface complexation reactions. In this article, methods for an experimental determination of these sites at the surface of α-FeOOH (goethite) are explored. It is shown that previously obtained saturation data of goethite with respect to protons do not yield a site density that can be considered as an intrinsic sorbent property: the results are below crystallographically expected values and values for different ionic media in terms of composition and concentration yield different numbers—for example, chloride would yield higher values than nitrate at the same concentration, and higher electrolyte concentration would favor higher apparent maxima. Although site saturation might be explained by electrostatic repulsion, which is more efficient at high electrolyte concentration or for certain ions, further independent experimental results show that no saturation occurs on goethite down to ph ≡ −log[H+] = 2.2 and possibly to PH = 1.0 in 0.6 M NaCl. For those very low pH values, the experimental charging curve was obtained by coulometric back titration (using the Gran plot) or titrations with tris (hydroxymethyl)-aminomethane of the supernatant of acidified goethite suspension. These experimental data are to our knowledge the first high quality data at such low pHs. However, small errors in the determination of proton concentrations (1%) are shown to strongly affect the shape of the charging curve for ph < 2. Furthermore, goethite dissolution (proton consumption and iron reduction in coulometric titrations) and liquid junction effects interfere at low ph, hampering the straightforward application of coulometric Gran titrations over the whole pH range. From these experiments, it can nonetheless be ascertained that a minimum of 2.5 protons/nm2 can be adsorbed at the goethite surface from the point of zero charge (ph 9.4) to pH 0.9. Although these studies are restricted to goethite, those studies in which titrations with excess acid and base have been used for the determination of proton active site concentrations of sorbents should be reconsidered.

  • 26.
    Lützenkirchen, Johannes
    et al.
    Institute for Nuclear Waste Disposal (INE), Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany.
    Preočanin, Tajana
    Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia.
    Kovačević, Davor
    Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia.
    Tomišić, Vladislav
    Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kallay, Nikola
    Division of Physical Chemistry, Department of Chemistry, Faculty of Science, University of Zagreb, Zagreb, Croatia.
    Potentiometric titrations as a tool for surface charge determination2012In: Croatica Chemica Acta, ISSN 0011-1643, E-ISSN 1334-417X, Vol. 85, no 4, p. 391-417Article in journal (Refereed)
    Abstract [en]

    This article summarizes methods for determining proton surface charge at mineral/water interfaces. It covers conventional experimental procedures and discusses problems with the techniques. Also it involves recommendations for obtaining reasonable and comparable results. The term "comparable results" refers to comparison between results for the same solid as obtained in different laboratories. The most important parameters for the surface titrations are discussed. We also propose a reference titration procedure that would allow direct, unbiased comparisons of experimental data. The article finally includes a check-list for researchers and reviewers which should allow limiting the amount of titration data that are not useful for future uses.

     

  • 27. Lützenkirchena, J.
    et al.
    Boily, J. F.
    Gunneriusson, L.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Protonation of different goethite surfaces—Unified models for NaNO3 and NaCl media2008In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 317, no 1, p. 155-165Article in journal (Refereed)
    Abstract [en]

    Acid–base titration data for two goethites samples in sodium nitrate and sodium chloride media are discussed. The data are modeled based on various surface complexation models in the framework of the multi site complexation (MUSIC) model. Various assumptions with respect to the goethite morphology are considered in determining the site density of the surface functional groups. The results from the various model applications are not statistically significant in terms of goodness of fit. More importantly, various published assumptions with respect to the goethite morphology (i.e., the contributions of different crystal planes and their repercussions on the “overall” site densities of the various surface functional groups) do not significantly affect the final model parameters within simple 1-pK approximations. The simultaneous fit of the chloride and nitrate data results in electrolyte binding constants, which are applicable over a wide range of electrolyte concentrations including mixtures of chloride and nitrate. Model parameters for the goethite sample with 90 m2/g specific surface area are in excellent agreement with parameters that were independently obtained by another group on different goethite titration data sets.

  • 28.
    Mangold, Stefanie
    et al.
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology).
    Potrykus, Joanna
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology). Aberdeen Fungal Group, University of Aberdeen, Scotland, UK.
    Björn, Erik
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Dopson, Mark
    Umeå University, Faculty of Science and Technology, Department of Molecular Biology (Faculty of Science and Technology). Centre for Ecology and Evolution in Microbial Model Systems, School of Natural Sciences, Linnaeus University, Kalmar, Sweden.
    Extreme zinc tolerance in acidophilic microorganisms from the bacterial and archaeal domains2013In: Extremophiles, ISSN 1431-0651, E-ISSN 1433-4909, Vol. 17, no 1, p. 75-85Article in journal (Refereed)
    Abstract [en]

    Zinc can occur in extremely high concentrations in acidic, heavy metal polluted environments inhabited by acidophilic prokaryotes. Although these organisms are able to thrive in such severely contaminated ecosystems their resistance mechanisms have not been well studied. Bioinformatic analysis of a range of acidophilic bacterial and archaeal genomes identified homologues of several known zinc homeostasis systems. These included primary and secondary transporters, such as the primary heavy metal exporter ZntA and Nramp super-family secondary importer MntH. Three acidophilic model microorganisms, the archaeon 'Ferroplasma acidarmanus', the Gram negative bacterium Acidithiobacillus caldus, and the Gram positive bacterium Acidimicrobium ferrooxidans, were selected for detailed analyses. Zinc speciation modeling of the growth media demonstrated that a large fraction of the free metal ion is complexed, potentially affecting its toxicity. Indeed, many of the putative zinc homeostasis genes were constitutively expressed and with the exception of 'F. acidarmanus' ZntA, they were not up-regulated in the presence of excess zinc. Proteomic analysis revealed that zinc played a role in oxidative stress in At. caldus and Am. ferrooxidans. Furthermore, 'F. acidarmanus' kept a constant level of intracellular zinc over all conditions tested whereas the intracellular levels increased with increasing zinc exposure in the remaining organisms.

  • 29. Maurice, Christian
    et al.
    Lidelöw, Sofia
    Gustavsson, Björn
    Lättström, Anders
    Umeå University, Faculty of Science and Technology, Chemistry.
    Ragnvaldsson, Daniel
    Leffler, Per
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Tesfalidet, Solomon
    Umeå University, Faculty of Science and Technology, Chemistry.
    Kumpiene, Jurate
    Techniques for the Stabilization and Assessment of Treated Copper-, Chromium-, and Arsenic-contaminated Soil2007In: AMBIO: A Journal of the Human Environment, Vol. 36, no 6, p. 430–6-Article in journal (Refereed)
    Abstract [en]

    Remediation mainly based on excavation and burial of the contaminated soil is impractical with regard to the large numbers of sites identified as being in need of remediation. Therefore, alternative methods are needed for brownfield remediation. This study was conducted to assess a chemical stabilization procedure of CCA-contaminated soil using iron (Fe)-containing blaster sand (BS) or oxygen-scarfing granulate (OSG). The stabilization technique was assessed with regard to the feasibility of mixing ameliorants at an industrial scale and the efficiency of the stabilization under different redox conditions. The stability was investigated under natural conditions in 1-m3 lysimeters in a field experiment, and the effect of redox conditions was assessed in a laboratory experiment (10 L). The treatments with high additions of ameliorant (8% and 17%) were more successful in both the laboratory and field experiments, even though there was enough Fe on a stochiometric basis even at the lowest addition rates (0.1% and 1%). The particle size of the Fe and the mixing influenced the stabilization efficiency. The development of anaerobic conditions, simulated by water saturation, increases the fraction of arsenic (AsIII) and, consequently, As mobility. The use of high concentrations of OSG under aerobic conditions increased the concentrations of nickel (Ni) and copper (Cu) in the pore water. However, under anaerobic conditions, it decreased the As leaching compared with the untreated soil, and Ni and Cu leaching was not critical. The final destination of the treated soil should govern the amendment choice, that is, an OSG concentration of approximately 10% may be suitable if the soil is to be landfilled under anaerobic conditions. Alternatively, the soil mixed with 1% BS could be kept under aerobic conditions in a landfill cover or in situ at a brownfield site. In addition, the treatment with BS appeared to produce better effects in the long term than treatment with OSG.

  • 30.
    Nelson, Hanna
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Loring, John
    Umeå University, Faculty of Science and Technology, Chemistry.
    Arsenate adsorption to goethite studied by combining spectroscopy and potentiometry2006Conference paper (Other academic)
  • 31.
    Nelson, Hanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Composition and solubility of precipitated copper(II) arsenates2011In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 26, no 5, p. 696-704Article in journal (Refereed)
    Abstract [en]

    Equilibrium reactions involving Cu(II) and As(V) have been studied with respect to formation of complexes in aqueous solutions as well as formation of solid phases. Potentiometric titrations performed at 25 °C (I = 0.1 M Na(Cl)) and at different Cu to As ratios gave no evidence for the existence of Cu(II) arsenate complexes in solution below the pH of the precipitation boundaries (pH ≈ 4), irrespective of the Cu to As ratio and pH. Mixing of solutions of Cu(II) and As(V) at different proportions and adjusting pH to values ranging from 4 to 9 resulted in precipitation of five different solid phases. The elemental composition of the solids was determined using X-ray Photoelectron Spectroscopy, and Environmental Scanning Microscopy–Field Emission Gun equipped with an energy dispersive spectroscopy detector. The average Cu/As ratio was determined by dissolving the solids. Total soluble concentrations of the components Cu(II) and As(V), as well as the basicity of the solid phases were determined by analysis of aqueous solutions. Based upon these experimental data the stoichiometric composition of the solid phases and their stability were determined. The resulting equilibrium model includes the solid phases Cu3(AsO4)2, Cu3(AsO4)(OH)3, Cu2(AsO4)(OH), Cu5Na(HAsO4)(AsO4)3 and Cu5Na2AsO4)4, where Cu5Na(HAsO4)(AsO4)3 and Cu5Na2(AsO4)4 have not been reported previously. In 0.1 M Na(Cl), Na+ was found to be a significant component in two of the solid phases. The Cu5Na2(AsO4)4 was formed in weakly alkaline conditions with pNa < 2.5. Stability constants for all solid phases have been determined. Distribution diagrams as well as predominance area (pNa–pH) diagrams are presented to illustrate stability fields of the different solid phases.

  • 32.
    Nelson, Hanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Monodentate inner–sphere coordination of Arsenate and Phosphate Anions, stabilized by Hydrogen Bonding, at the Goethite/Water InterfaceManuscript (preprint) (Other academic)
  • 33.
    Nelson, Hanna
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Surface complexation modeling of arsenate and copper adsorption to the goethite surface2007Conference paper (Other academic)
  • 34.
    Nelson, Hanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Surface complexation modelling of arsenate and copper adsorbed at the goethite/water interface2013In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 35, p. 64-74Article in journal (Refereed)
    Abstract [en]

    The co-adsorption of Cu(II) and arsenate onto the surface of goethite has been studied by performing adsorption experiments and potentiometric titrations, and a surface complexation model has been developed to describe the experimental results. Models for the binary systems, Cu-goethite and arsenate-goethite, were acquired separately and the model parameters were then included in the ternary system, together with the solubility products of solid Cu(II) arsenates reported in the literature. The adsorption of Cu(II) was described applying a model in which Cu(II) forms bidentate bridging mono- and binuclear surface complexes. According to recent interpretations of ATR-FTIR and EXAFS data the arsenate ions are assumed to be coordinated in a monodentate fashion to singly coordinated hydroxyl groups at the surface, and hydrogen-bonded to neighbouring triply coordinated surface oxide sites. In the case of co-adsorption of Cu(II) and arsenate, the adsorption could not be predicted by applying the combined model from the two binary systems. Two ternary Cu(II)-arsenate-goethite surface complexes must be included, one complex in which an arsenate ion is coordinating to surface Fe(III) (≡FeOAsO3Cu0.5-) and one complex in which arsenate is bound to the surface by coordinating to an adsorbed Cu(II) ion (≡(Fe3OFeOH)Cu2(OH)2HAsO41-). No solid Cu (II) arsenate phases were formed under the experimental conditions in the present study. From constructed predominance area diagrams, the significance of adsorption and precipitation processes are discussed. Furthermore, calculated solubility of Cu(II) and As(V) is used to indicate optimum conditions for the cleaning of contaminated natural waters.

  • 35.
    Persson, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Tove
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nelson, Hanna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Surface complexes of monomethyl phosphate stabilized by hydrogen bonding on goethite (α-FeOOH) nanoparticles2012In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 386, no 1, p. 350-358Article in journal (Refereed)
    Abstract [en]

    Typically, a significant fraction of phosphorus in soils is composed of organic phosphates, and this fraction thus plays an important role in the global phosphorus cycle. Here we have studied adsorption of monomethyl phosphate (MMP) to goethite (α-FeOOH) as a model system in order to better understand the mechanisms behind adsorption of organic phosphates to soil minerals, and how adsorption affects the stability of these molecules. The adsorption reactions and stability of MMP on goethite were studied at room temperature as a function of pH, time and total concentration of MMP by means of quantitative batch experiments, potentiometry and infrared spectroscopy. MMP was found to be stable at the water-goethite interface within the pH region 3-9 and over extended periods of time, as well as in solution. The infrared spectra indicated that MMP formed three predominating pH-dependent surface complexes on goethite, and that these interacted monodentately with surface Fe. The complexes differed in hydrogen bonding interactions via the auxiliary oxygens of the phosphate group. The presented surface complexation model was based on the collective spectroscopic and macroscopic results, using the Basic Stern approach to describe the interfacial region. The model consisted of three monodentate inner sphere surface complexes where the MMP complexes were stabilized by hydrogen bonding to a neighboring surface site. The three complexes, which had equal proton content and thus could be defined as surface isomers, were distinguished by the distribution of charge over the 0-plane and β-plane. In the high pH-range, MMP acted as a hydrogen bond acceptor whereas it was a hydrogen bond donor at low pH.

  • 36.
    Persson, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Tove
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nelson, Hanna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Giesler, Reiner
    Umeå University, Faculty of Science and Technology, Department of Ecology and Environmental Sciences.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Surface complexes of Monomethyl Phosphate stabilized by Hydrogen Bonding on Goethite (α-FeOOH) NanoparticlesManuscript (preprint) (Other academic)
  • 37.
    Persson, Per
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nordin, Jan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Rosenqvist, Jörgen
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Öhman, Lars-Olof
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Comparison of the adsorption of o-phthalate on boehmite (γ-AlOOH), aged γ-Al2O3, and goethite (α-FeOOH)1988In: Journal of Colloid and Interface Science, ISSN 0021-9797, E-ISSN 1095-7103, Vol. 206, no 1, p. 252-266Article in journal (Refereed)
    Abstract [en]

    This work is concerned with the adsorption of o-phthalate (1,2-benzenedicarboxylate) at the water-metal (hydr)oxide interface. Previously published infrared spectroscopic, potentiometric, and adsorption data characterizing the boehmite (gamma-AlOOH) system are compared with new data collected for o-phthalate adsorption on aged gamma-Al2O3 and goethite (alpha-FeOOH). The study focuses on identifying bonding mechanisms, stoichiometries, and stabilities of the formed complexes, and comparing these among the three systems. Furthermore, the effects of ionic strength and composition of the ionic medium are investigated. The infrared spectroscopic data provided direct, molecular-level evidence for the existence of two dominating surface complexes on all three solids. One was shown to be a deprotonated outer-sphere species and the other was an inner-sphere surface complex. The inner-sphere complexes on the three solids were structurally related, and they were tentatively assigned to a mononuclear, chelating structure involving both carboxylate groups. The outer-sphere complexes were shown to increase in relative importance at high pH and low ionic strengths, while low pH and high ionic strengths favored the inner-sphere complexes. The information gained from the infrared spectroscopic investigations was used as qualitative input in the formulation of the surface complexation models. New models, based on the extended constant capacitance approach, were presented for the o-phthalate/aged gamma-Al2O3 and o-phthalate/goethite systems.

  • 38.
    Ragnvaldsson, Daniel
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lättström, Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tesfalidet, Solomon
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Leffler, Per
    Umeå University, Faculty of Medicine, Department of Public Health and Clinical Medicine, Occupational and Environmental Medicine.
    Arsenic chemical species-dependent genotoxic potential in water extracts from two CCA-contaminated soils measured by DNA-repair deficient CHO-cells2009In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 407, no 14, p. 4253-4260Article in journal (Refereed)
    Abstract [en]

    Two soils with similar contamination levels from wood preservatives containing Chromium (Cr), Copper (Cu) and Arsenic (As) (CCA), were assessed for their general toxicity and genotoxicity. A set of water-based extraction methods, including pressurized liquid extraction (PLE), and batch leaching in milli-Q water and a weak CaCl2-solution, was used to produce soil extracts containing available fractions of contaminants. In addition, to obtain indications of the contaminants' bioavailability and toxic potential the genotoxicity of the extracts was estimated by testing their ability to inhibit the growth of wildtype Chinese hamster ovary cells (CHO-cells) and three genetically modified pheno-types that are deficient in different DNA-repair mechanisms. Total extractable arsenic concentrations in the extracts were comparable between the sites. However, the genotoxic potential was clearly higher in soil R extracts. The differences in genotoxic responses were related to differences in inorganic arsenic speciation. The ratio of trivalent arsenic (AsIII) to pentavalent arsenic (AsV) was higher in all soil extracts from soil R, regardless of the leaching method used. The results of the various combinations of soil extraction techniques and assays using the CHO-cell lines reflected important differences in arsenic speciation in the two soils and possible synergistic effects in CCA-related exposure. They also indicate that speciation and combinatory effects are factors that should be taken into account when assessing risks at former wood impregnation sites contaminated by CCA-agents.

  • 39.
    Ramstedt, Madeleine
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Carlsson, Erik
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Aqueous geochemistry in the Udden pit lake, northern Sweden2003In: Applied Geochemistry, Vol. 18, no 1, p. 97-108Article in journal (Refereed)
    Abstract [en]

    The Udden pit lake in northern Sweden was studied from June 1998 to February 1999 in order to increase knowledge of the geochemistry in lakes created as a result of decommissioning open pit mines. The vertical water profile in the lake was sampled on 4 different occasions, in June, August, September and February. Water samples were analysed for total concentrations of Fe, As, Cu, Cd, Zn, Pb, Al, Ca, K, Mg, Na, Mn, S, Cl, N and P. Temperature, concentration of dissolved O2, conductivity, pH, and redox potential were measured in situ at different depths. Four layers could be observed in the lake during summer, and 3 layers during winter. A thermocline was observed during summer at a depth of 5 m and on all 4 occasions a halocline was observed at a depth of 20 m, and a redoxcline at 35 m. Oxygen concentration decreased dramatically at a depth of 20 m. pH increased downwards in the lake from 4.8 at the surface to 6.4 at the bottom of the lake. Geochemical processes occurring in the lake, the origins of the layers, the metal concentrations and the anion concentrations are discussed in this article.

  • 40. Shtangeeva, Irina
    et al.
    Tesfalidet, Solomon
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Comparison of nutrient concentrations in leaves of five plants2017In: Journal of plant nutrition, ISSN 0190-4167, E-ISSN 1532-4087, Vol. 40, no 2, p. 239-247Article in journal (Refereed)
    Abstract [en]

    The paper describes investigation on bioaccumulation of mineral elementsand identification of plants based on the concentrations of the elements inthe plant leaves. Five native plant species (Elytrigia repens, Plantago major,Urtica dioica, Chelidonium majus, and Taraxacum officinale) were studied. Toexclude the effects from different growth conditions and developmentalstages, the plants were collected simultaneously from the same site (park inSt. Petersburg, Russia). It was found that for all plants high concentrations ofpotassium, sodium, phosphorus and magnesium (K, Na, P, and Mg) weretypical, while concentrations of zinc (Zn) and copper (Cu) were the lowest.The most significant difference was found between concentrations ofelements in monocots and eudicots. Among other species,T. officinalehadthe highest concentrations of almost all elements. Excellent separation of theplants into different groups which was due to different elementconcentrations in the plant leaves was demonstrated.

  • 41.
    Öberg, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Andersson, Barbro
    Umeå University, Faculty of Science and Technology, Chemistry.
    Andersson, Patrik
    Umeå University, Faculty of Science and Technology, Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Johansson, M
    Umeå University, Faculty of Science and Technology, Chemistry.
    Karlsson, S
    Lundstedt, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Marklund, Ann
    Umeå University, Faculty of Science and Technology, Chemistry.
    Nording, Malin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Undergraduate Education in Environmental Chemistry at Umeå University, Sweden2004In: SETAC 4th World Congress/25th Annual Meeting in North America, 14-18 November, Portland OR, USA, 2004Conference paper (Other academic)
    Abstract [en]

    Abstract to the Fourth SETAC World Congress, oral presentation.

  • 42.
    Öhman, Lars-Olof
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lövgren, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Hedlund, Tomas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sjöberg, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The ionic strength dependency of mineral solubility and chemical speciation in solution2006In: Surface Complexation Modelling, Elsevier, 2006, p. 1-34Chapter in book (Other academic)
1 - 42 of 42
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf