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  • 1.
    Allard, Bert
    et al.
    Örebro University, School of Science and Technology.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Greis, Christina
    Örebro University, Department of Natural Sciences.
    Pettersson, Håkan
    Linköpng Univ.
    Düker, Anders
    Örebro University, School of Science and Technology.
    Redistribution of Pu, Am, Cs and Np in salt marsh sediment: Wigtown Merse, Irish Sea2009In: 8th International Conference on Methods and Applications of Radioanalytical Chemistry (MARC VIII) / [ed] Rolf Zeisler, Kenan Ünlü, Susan Heller-Zeisler, Melville, N.Y.: American Institute of Physics (AIP), 2009, p. 1-24Conference paper (Refereed)
  • 2.
    Elgh-Dalgren, Kristin
    et al.
    Örebro University, School of Science and Technology.
    Düker, Anders
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    van Hees, Patrick
    Örebro University, School of Science and Technology.
    Simultaneous re­mediation of explosives and lead from contaminated soil by pH-adjust­mentManuscript (preprint) (Other academic)
    Abstract [en]

    Soil washing with pH-adjusted water was evaluated in two soils containing dif­ferent concentrations of heavy metals and explosives. Overall, the most efficient treatment was with water adjusted to pH 12 by NaOH. For explosives, pH 12 removed significantly higher amounts (P<0.05) of RDX and TNT compared to pH 4 (adjusted with HNO3) and distilled water in a moderately contaminated soil (230 mg HMX/kg, 1340 mg RDX/kg, 450 mg TNT/kg). In a more highly contaminated soil (6080 mg HMX/kg, 28740 mg RDX/kg, 3120 mg TNT/kg), the pH 12-treatment was the most efficient for removal of TNT and 2,4-DNT. Explosives removal increased with treatment time, probably due to the kineti­cally slow processes underlying the explosives degradation. Mobilization of heavy metals was strongly dependent on pH, with pH 12 mobilizing more than pH 3. In addition, the change in distribution coefficient (Kd) was more pro­nounced for local contaminants Pb and Cd in comparison with Cu and Zn, which were present in background concentrations.

  • 3.
    Elgh-Dalgren, Kristin
    et al.
    Örebro University, School of Science and Technology.
    Düker, Anders
    Örebro University, School of Science and Technology.
    Arwidsson, Zandra
    Örebro University, School of Science and Technology.
    von Kronhelm, Thomas
    van Hees, Patrick A. W.
    Örebro University, School of Science and Technology.
    Re-cycling of remediated soil: evaluation of leaching tests as tools for characterization2011In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 31, no 2, p. 215-224Article in journal (Refereed)
    Abstract [en]

    In Sweden, leaching tests with deionized water (D.W.) are frequently utilized in risk assessment, but implementation of these results to evaluate the risk of spreading in the environment is difficult. One problem is that most leaching procedures only consider heavy metals release, whereas organic pollutants are left out. The aim of the present study was to assess the possible pollutant miti­gation in four remediated soils, three with heavy metals and one with polycyclic aromatic hydrocarbons (PAH), utilizing three different leaching solutions: D.W., a weak ionic solution (0.001 M CaCl2) and an artificially made soil wa­ter (ASW). In general, batch leaching implied larger contaminant removal than column leaching, possibly due to the more rough treatment of the soil particles, and guidelines would at times be exceeded by batch leaching but not column leaching. Utilization of CaCl2 was found to release much less heavy metal than D.W., whereas the metals mobilized by ASW were removed from solution by the filtration of soil leachates. Low molecular weight PAH was most efficiently mobilized by CaCl2, while D.W. worked better for high molecular weight PAH. Despite very low initial PAH-concentrations, tap- and groundwater criteria were exceeded by all leaching solutions.

  • 4.
    Elgh-Dalgren, Kristin
    et al.
    Örebro University, School of Science and Technology.
    Waara, Sylvia
    Mälardalen University.
    Düker, Anders
    Örebro University, School of Science and Technology.
    von Kronhelm, Thomas
    SAKAB AB.
    van Hees, Patrick A. W.
    Örebro University, School of Science and Technology.
    Anaerobic bioremediation of a soil with mixed contaminants: Explosives degradation and influence on heavy metal distribution, monitored as changes in concentration and toxicity2009In: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 202, no 1-4, p. 301-313Article in journal (Refereed)
    Abstract [en]

    Two soils with explosives and metals were evaluated for the degradation efficiency of explosives by native microorganisms under anaerobic conditions. The commercially available method Daramend®, amended with zero-valent iron (ZVI), was compared with a horse-manure amended compost and a treatment with ZVI alone. In a moderately contaminated soil, Daramend® and ZVI treatment gave significantly higher removal rates compared  to compost and control treatments (Tukey’s test, P<0.05). The largest overall decrease in ecotoxicity, measured with bioluminescent bacteria (Vibrio fischeri), was achieved with ZVI-treatment. In a more contaminated soil no degradation of contaminants and no decline in soil toxicity could be distinguished after the same time period. Problems with establishment of anaerobic conditions during parts of the remediation process and low microbial activity due to acute toxicity of contaminants are plausible explanations. Redistribution that could potentially lead to mobilization of the co-contaminant Pb was not observed in either of the soils during the biological treatments.

  • 5.
    Grahn, Evastina
    et al.
    Örebro University, Department of Natural Sciences.
    Greis, Christina
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Pettersson, Håkan
    Failure of 137Cs and 239/240Pu dating of lake sediments: fallout from nuclear weapons testing and from the Chernobyl accident as well as redistribution processes?Manuscript (Other academic)
  • 6.
    Grahn, Evastina
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Sediment reference concentrations of seldom monitored trace elements (Ag, Be, In, Ga, Sb, Tl) in four Swedish boreal lakes: comparison with commonly monitored elements2006In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 367, no 2-3, p. 778-790Article in journal (Refereed)
    Abstract [en]

    This paper presents reference and recent acid-leachable concentrations of some seldom monitored trace elements (SMTE; Ag, Be, Ga, In, Sb and Tl) in sediments from four boreal oligotrophic lakes in a south to north transect in Sweden. For comparison commonly monitored trace elements (As, Cd, Co, Cr, Cu, Ni, Pb and Zn) are included as well as those of relevance for redistribution processes (Al, Ca, Fe, Mg and Mn).

    Pore water pH and the corresponding solid/solution distribution coefficients (Kd) indicated that redistribution of the elements due to acidification is minor. The depth of impact was defined as the level in the sediment where the mean values became constant on successive exclusion of metal concentrations in overlying strata. Reference concentrations were calculated below the depth of impact. The present concentration changes are estimated by the ratio between the average concentration above the depth of impact and the reference concentration.

    Reference concentration ranges for the SMT-elements are (mg/kg, dry wt.): Ag 0.16–0.66; Be 1.6–3.7; Ga 2.0–5.1; In 0.05–0.22; Sb 0.05–0.11 and Tl 0.17–0.70. The concentration ratios for these elements ranged in the two most southern lakes from 1.5 to 4.5 and in the two northern ones from 0.6 to 1.6. A high correlation between Kd for the SMT-elements, and iron, except for Sb and Tl, infer that the biogeochemistry of iron is quantitatively important for the accumulation of these elements.

    The reference concentration ranges for the commonly monitored trace elements are (mg/kg, dry wt.): As 7.0–29.6; Cd 0.33–0.98; Co 5.7–23.8; Cr 15.2–26.1; Cu 27.6–58.4; Ni 5.4–20.8; Pb 44–96. The corresponding concentration ratios were 1.2–18 (second highest 3.9) in the two most southern lakes and 0.8–1.6 in the two northern ones. Declining ratios were found from south to north, most obvious for cobalt and zinc. The copper ratios did not show a regional pattern, partly because of the impact from old mine waste.

    Increased concentrations of Ag, Be, Ga, In, Sb and Tl in recent sediments up to 4.5 times the reference levels in combination with the geographical pattern infer an elevated loading of these elements.

  • 7.
    Grahn, Evastina
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Seldom monitored trace elements (Ag, Au, Ga, In, Sb, Tl) in two urban lake sediments in Central Sweden: a case studyManuscript (Other academic)
  • 8.
    Grahn, Evastina
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Karlsson, Ulrika
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Historical pollution of seldom monitored trace elements in Sweden: Part B: sediment analysis of silver, antimony, thallium and indium2006In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 8, no 7, p. 732-744Article in journal (Refereed)
    Abstract [en]

    Sediment cores from four boreal and remote lakes in a south to north transect in central Sweden were analysed for acid leachable silver, antimony, thallium and indium in the solid sediment phase and the corresponding porewater. Dating of the cores was made by their content of acid leachable lead and the 206Pb/207Pb ratio, in one lake also by 210Pb. The impact of diagenesis on element redistribution in the sediments was included and found to be minor except for thallium. The results show lowered concentrations towards the north and most intense accumulation after the Second World War, which is taken as evidence for atmospheric deposition being the primary source. Indium has declining concentrations in recent strata while silver and antimony increase. Thallium has lowered acid-leachable concentrations in recent strata. For all metals the impact of domestic industrialisation as well as the early industrialisation of central Europe is discernible. Only thallium appears to reach a geological background at depths that correspond to the late 18th century. For the other metals elevated levels are concluded.

  • 9.
    Greis, Christina
    et al.
    Örebro University, Department of Natural Sciences.
    Duker, Anders
    Man-Technology-Environment Research Centre, Örebro University, Örebro, Sweden.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Roos, Per
    Department of Radiation Physics, Lund University Hospital, Lund, Sweden; Risø National Laboratory, Roskilde, Denmark.
    Holm, Elis
    Department of Radiation Physics, Lund University Hospital, Lund, Sweden; .
    Plutonium remobilization in a humic-rich lake2007In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 277, no 1, p. 265-268Article in journal (Refereed)
    Abstract [en]

    Fresh water from Lake Svartsjön, Sweden, was collected and four fractions were prepared: (1) adsorption on DEAE, (2) flocculation with Ca2+, (3) co-precipitation with Fe hydrous oxide and (4) co-precipitation with Mn hydrous oxide. The plutonium level in the lake is 65 fg/l (222 μBq/l), measured by ICP-QMS and ICP-SFMS. Pronounced accumulation in fractions (1) (34%) and (2) (66%), combined with observed levels of organic matter indicate that plutonium is predominantly associated with organic matter. Measurements of isotopic ratios indicate that 77% of the plutonium originates from weapons testing and the remaining appears to originate from the Chernobyl accident.

  • 10.
    Greis, Christina
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Pettersson, Håkan
    Radiofysikavdelningen, O-centrum US, Universitetssjukhuset, Linköping, Sweden .
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Determination of plutonium in environmental samples with quadrupole ICP-MS2008In: Journal of Radioanalytical and Nuclear Chemistry, ISSN 0236-5731, E-ISSN 1588-2780, Vol. 275, no 1, p. 55-70Article in journal (Refereed)
    Abstract [en]

    A method for rapid determination of plutonium isotopes in environmental samples with ultrasonic nebulisation and quadrupole ICP-MS detection was established. Techniques for sample dissolution, pre-concentration and chemical separation were evaluated and the optimal scheme outlined. Comparisons with α-spectrometry and high resolution ICP-MS confirmed the suitability of the method when applied to different environmental matrices within the global fallout concentration range in the northern hemisphere as well as more contaminated sites. Operational detection limits were 0.5–1.5 fg/l for fresh waters and 0.03–0.1 ng/kg for lake sediments and saline marsh sediments.

  • 11.
    Karlsson, Stefan
    et al.
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Grahn, Evastina
    Örebro University, Department of Natural Sciences.
    Sediment chronologies of As, Bi, and Ga in Sweden - impact of industrialisation2007In: Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering, ISSN 1093-4529, E-ISSN 1532-4117, Vol. 42, no 2, p. 155-164Article in journal (Refereed)
    Abstract [en]

    The acid-leachable amount and pore water concentration of As, Bi and Ga in sediment cores from four remote lakes in a south to north transect in Sweden were used to recapitulate the pollution history of the elements. The diagenetic impact on the element distribution was elucidated from their solid/solution partition and relationships to elements indicative for diagenesis. Dating was made by their acid-leachable lead content in combination with the Pb-206/Pb-207 ratio. In one of the lakes this approach was validated against dating with Pb-210. The impact of diagenesis on the sediment distribution of theses elements was found to be low enough for a chronological interpretation of the sediment profiles, as evidenced by their ratios to elements indicative of the geological background. A closer examination of the diagenetic impact would however be required if a more detailed chronology is desired. This study has demonstrated that atmospheric deposition of arsenic, bismuth and gallium contributes to the sediment inventory of these elements. The major part of the deposition of arsenic and bismuth took place after the Second World War. For gallium no concentrations exceeding background were detected before circa 1930. Increased levels of arsenic are traceable to circa 1850. For bismuth increased levels are concluded to extend before 1790, i.e., background concentrations were not reached in the present cores. For all elements the atmospheric deposition has been lower towards the north.

  • 12.
    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.

  • 13.
    Karlsson, Ulrika
    et al.
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Separation and quantification of Tl(I) and Tl(III) in fresh water samples2006In: Journal of Environmental Science and Health. Part A: Toxic/Hazardous Substances and Environmental Engineering, ISSN 1093-4529, E-ISSN 1532-4117, Vol. 41, no 7, p. 1155-1167Article in journal (Refereed)
    Abstract [en]

    The two oxidation states of thallium, Tl(I) and Tl(III), were quantified by IC-ICP-MS using complexation of Tl3+ with DTPA (penta-carboxymethyl-diethylenetriamine) and separation on a cation exchange column according to a modification of the method devised by Coetzee et al. In order to avoid successively lowered separation efficiency and loss of resolution during a run, a gradient elution was made using HCl instead of HNO3. With an ultrasonic nebuliser instead of a V-groove nebuliser the limit of detection for Tl(I) and Tl(III) could be lowered from 25 ng/L and 3.0 ng/L to 9.0 ng/L and 0.7 ng/L, respectively, which is adequate for many fresh water systems. The stability of Tl(III) in acidic solutions was found to be concentration dependent, with an initially high reduction rate of Tl(III). Exposure of the sample to light further increased the reduction rate. Addition of DTPA (0.01 mM) and acid (HNO3, 1%) to a sample with 1 μg/L Tl(III) stabilised the Tl(III) content for at least 48 h. Analysis of field samples showed that only acidification is inadequate to maintain the original distribution of Tl(I) and Tl(III). Internal calibration (standard addition) and correction of the analytical signal (205Tl) with a non-ionic internal standard (11B) yielded almost quantitative recoveries of both Tl(I) and Tl(III). A scheme for field sample preparation is proposed, including sampling, storage and pre-analysis treatment.

  • 14.
    Karlsson, Ulrika
    et al.
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    The effect of light and iron(II)/iron(III) on the distribution of Tl(I)/Tl(III) in fresh water systems2006In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 8, no 6, p. 634-640Article in journal (Refereed)
    Abstract [en]

    The distribution of aqueous Tl(I)/Tl(III) as a function of light exposure and solution properties was studied by quantifying the oxidation states after separation with ion chromatography and on-line detection with ICP-MS. Ultraviolet irradiation of aqueous solutions containing 1 μg l−1 Tl(III) and in equilibrium with the atmosphere increases the reduction rate. In systems with photoreduction of Fe(III)(aq) a quantitative oxidation of Tl(I)(aq) was observed, notably at low pH. The process is reversible, as indicated by formation of Tl(I) when the irradiated systems were kept in the dark. In systems with colloidal silica-stabilised ferrihydrite, UV irradiation also leads to oxidation of Tl(I)(aq), but not quantitatively. It is suggested that adsorption of thallium to the ferrihydrite determines the rate of oxidation. Detectable, but not quantitative, oxidation of Tl(I)(aq) took place when natural water samples with 1 μg l−1 Tl(I)(aq) were exposed to either sunlight or UV-light. For these samples, the reduction was not quantitative when they were kept in the dark for 24 h. The results suggest that the light dependent iron cycle in fresh water systems strongly influences the redox state of thallium.

  • 15.
    Svensson, Margareta
    et al.
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Formation of HgS: mixing HgO or elemental Hg with S, FeS or FeS22006In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 368, no 1, p. 418-423Article in journal (Refereed)
    Abstract [en]

    The aim of this study is to assess the feasibility for generation of the sparingly soluble solid HgS from HgO or elemental Hg by mixing with a suitable sulphur source under various conditions (dry, wet at different pH, and room temperature). The formation of mercury sulphide was confirmed in 14 of the 36 combinations of Hg and S sources. Mercury sulphide was generally formed under alkaline conditions. Almost 100% HgS was obtained in anaerobic systems at high pH in the presence of elemental sulphur after about two years. Thus, it is feasible to create an environment at room temperature that, with time, leads to the generation of HgS from elemental Hg or HgO. This is relevant for the design of a repository for permanent geologic disposal of mercury. Choosing wrong components and conditions can however lead to a reduction of Hg(II) to elemental mercury.

  • 16.
    Svensson, Margareta
    et al.
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Formation of cinnabar: an estimation of favourable conditions2006Manuscript (preprint) (Other academic)
  • 17.
    Svensson, Margareta
    et al.
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Formation of cinnabar: estimation of favourable conditions in a proposed Swedish repository2006In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 136, no 3, p. 830-836Article in journal (Refereed)
    Abstract [en]

    A deep repository for permanent storage of mercury will be designed and built in Sweden. The preferred chemical state for mercury in such a repository would be the sulphide HgS (cinnabar), which is a highly insoluble and the dominating natural mercury mineral. The possible formation of HgS from HgO or Hg(0) by reaction with a sulphur source (S, FeS or FeS2) is discussed from thermodynamic considerations, and pe–pH-diagrams are constructed by using the computer code MEDUSA to illustrate under which conditions HgS would dominate. Calculations of the speciation (PHREEQE) under varying conditions (S/Hg-ratios, presence of chloride) are given.

    Long-term laboratory experiments are performed, where the formation of HgS from the basic components is demonstrated (after mixing under various conditions and storage at room temperature for up to 3 years).

    The feasibility of HgS-formation with time in a geologic repository under conditions representative of deep granitic bedrock (calcium-bicarbonate buffered to pH 7–8.5) is discussed, as well as effects of alkaline conditions (concrete environment, pH 10.5–12.5). Formation of soluble polysulphides is not expected as long as the S/Hg mole ratio is within 1–1.3 and pH is below 10.5–11. Concrete should be used with caution. Suitable ballast materials could be introduced that would reduce porewater-pH that otherwise would be above 12.

  • 18.
    Svensson, Margareta
    et al.
    Örebro University, Department of Natural Sciences.
    Hagelberg, Erik
    Düker, Anders
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Speciation and solubility of mercury in aerobic solutionsManuscript (Other academic)
  • 19.
    Temnerud, Johan
    et al.
    Örebro University, Department of Natural Sciences.
    Duker, Anders
    Örebro University, Department of Natural Sciences.
    Karlsson, Stefan
    Örebro University, Department of Natural Sciences.
    Allard, Bert
    Örebro University, Department of Natural Sciences.
    Köhler, Stephan
    Dept. of Applied Geosciences, Technical University of Graz, Graz, Austria.
    Bishop, Kevin
    Dept. of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Landscape scale patterns in the character of natural organic matter in a Swedish boreal stream network2009In: Hydrology and Earth System Sciences, ISSN 1027-5606, E-ISSN 1607-7938, Vol. 13, no 9, p. 1567-1582Article in journal (Refereed)
    Abstract [en]

    This paper defines landscape-scale patterns in the character of natural organic matter (NOM) and tests for relationships to catchment soil, vegetation and topography. The drainage network of a boreal catchment, subcatchment size 0.12-78 km(2), in Northern Sweden was sampled in August 2002 during a period of stable low water flow. The NOM was characterized with UV/Vis spectroscopy, fluorescence, XAD-8 fractionation (%humic substances), gel permeation chromatography (apparent molecular weight), and elemental composition (C:N). The largest spatial variation was found for C: N, absorbance ratio, and specific visible absorptivity. The lowest variation was in fluorescence index, %humic substances and molecular retention time. The variation in total organic carbon (TOC), iron and aluminium concentration was more than twice that of C: N. Between headwater and downstream sites no significant changes were distinguished in the NOM character. At stream reaches, junctions and lakes little change (<10%) in NOM character was observed. Common factor analysis and partial least squares regression (PLS) revealed that the spatial variation in surface coverage of lakes and mires could explain some of the variation of TOC and NOM character. Our suggestion is that the mosaic of landscape elements (different amounts of water from lakes, forest soil and mires) delivers NOM with varying characteristics to a channel network that mixes conservatively downstream, with possible small changes at some stream reaches, junctions and lakes.

  • 20.
    Temnerud, Johan
    et al.
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden; Swedish Meteorological and Hydrological Institute, Research Department, Norrköping, Sweden .
    Düker, Anders
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Karlsson, Stefan
    Örebro University, School of Science and Technology.
    Allard, Bert
    Örebro University, School of Science and Technology.
    Bishop, Kevin
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden; Department of Earth Sciences, Uppsala University, Uppsala, Sweden .
    Föster, Stephan
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden .
    Köhler, Stephan
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden .
    Spatial patterns of some trace elements in four Swedish stream networks2013In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 10, no 3, p. 1407-1423Article in journal (Refereed)
    Abstract [en]

    Four river basins in southern Sweden, with catchment sizes from 0.3 to 127 km2 (median 1.9), were sampled in October∼2007. The 243 samples were analysed for 26 trace elements (Ag, As, Au, Ba, Be, Bi, Cd, Co, Cr, Cu, Ga, Ge, In, La, Li, Mo, Ni, Pb, Sb, Se, Sn, Tl, Ti, U, V and Zn) to identify spatial patterns within drainage networks. The range and median of each element were defined for different stream orders, and relationships to catchment characteristics, including deposition history, were explored. The sampling design made it possible to compare the differences along 40 stream reaches, above and below 53 stream junctions with 107 tributaries and between the 77 inlets and outlets of 36 lakes. The largest concentration differences (at reaches, junctions and lakes) were observed for lakes, with outlets usually having lower concentration compared to the inlets for As, Ba, Be, Bi, Cd, Co, Cr, Ga, Ge, Ni, Pb, Sn, Ti, Tl, U, V and Zn. Significantly lower concentrations were observed for Cd and Co when comparing headwaters with downstream sites in each catchment. Common factor analysis (FA) revealed that As, Bi, Cr, Ga, Ge, Tl and V co-vary positively with Al, Fe and total organic carbon (TOC) and negatively with La, Li and pH. The strong removal of a large number of trace elements when passing through lakes is evident though in the FA, where lake surface coverage plots opposite to many of those elements. Forest volume does not respond in a similar systematic fashion and, surprisingly, the amount of wetland does not relate strongly to either Fe or TOC at any of the rivers. A better understanding of the quantitative removal of organic carbon and iron will aid in understanding trace element fluxes from landscapes rich in organic matter and iron.

  • 21.
    Temnerud, Johan
    et al.
    Örebro University, Department of Natural Sciences.
    Düker, Anders
    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.
    Köhler, Stephan
    Dept. of Applied Geosciences, Technical University of Graz, Graz, Austria.
    Bishop, Kevin
    Dept. of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Landscape scale patterns in the character of natural organic matter in a Swedish boreal stream network2009Conference paper (Refereed)
1 - 21 of 21
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