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  • 1.
    Conrad, Sarah
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Gelting, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nordblad, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden .
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden .
    Andersson, Per S.
    Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden.
    Porcelli, Don
    Department of Earth Sciences, Oxford University, Oxford, UK.
    Gustafsson, Örjan
    Department of Environmental Science and Analytical Chemistry, Stockholm University, Stockholm, Sweden.
    Semiletov, Igor
    International Arctic Research Center (IARC), University of Alaska, Fairbanks, AK, USA. Pacific Oceanological Institute (POI), Far Eastern Branch of the Russian Academy of Sciences (FEBRAS), Vladivostok, Russia. Tomsk National Research Politechnical University, Arctic Seas Carbon International Research Laboratory, Tomsk, Russia.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea2019Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 16, nr 6, s. 1305-1319Artikel i tidskrift (Refereegranskat)
    Abstract [en]

     Riverine Fe input is the primary Fe source for the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate ( >  0.22 μm), colloidal (0.22 μm–1 kDa), and truly dissolved (<  1 kDa) fractions of Fe was carried out. The total Fe concentrations ranged from 0.2 to 57μM with Fe dominantly as particulate Fe. The loss of >  99% of particulate Fe and about 90% of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative δ56Fe values (relative to IRMM-14). The colloidal Fe phase showed negative δ56Fe values close to the river mouth (about -0.20 ‰) and positive δ56Fe values in the outermost stations (about +0.10 ‰). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative δ56Fe values, representing chemically reactive ferrihydrites. The positive δ56Fe values of the colloidal phase within the outer Lena River freshwater plume might represent Fe oxyhydroxides, which remain in the water column, and will be the predominant δ56Fe composition in the Arctic Ocean.

  • 2.
    Rodushkin, Ilia
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Paulukat, Cora
    ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Pontér, Simon
    ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Baxter, Douglas
    ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Sörlin, Dieke
    ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Pallavicini, Nicola
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå.
    Rodushkina, Katerina
    Department of Chemistry, Uppsala University, Uppsala.
    Application of double-focusing sector field ICP-MS for determination of ultratrace constituents in samples characterized by complex composition of the matrix2018Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 622-623, s. 203-213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The performance of double focusing, sector field mass spectrometry (ICP-SFMS) for determination of analytes, including technology critical elements (TCE), at ultra-trace levels in environmental and clinical matrices was critically evaluated. Different configurations of the ICP-SFMS introduction system as well as various sample preparations, pre-concentration and matrix separation methods were employed and compared. Factors affecting detection capabilities and accuracy of data produced (instrumental sensitivity, contamination risks, purity of reagents, spectral interferences, matrix effects, analyte recovery and losses) were discussed. Optimized matrix-specific methods were applied to a range of reference and control materials (riverine, brackish and seawaters; whole blood, serum and urine) as well as tap water and snow samples collected in the area of Luleå city, northern Sweden; brackish and seawater from the Laptev Sea; venous blood samples with a special emphasis on determination of Au, Ag, Ir, Os, Pd, Pt, Re, Rh, Ru, Sb and Te. Even though these low abundant elements are relatively under-documented, the results produced were compared with published data, where available.

  • 3.
    Ingri, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Conrad, Sarah
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Lidman, Fredfrik
    Department of Forest Ecology and Management, Swedish University of Agricultural Sciences, Umeå.
    Nordblad, Fredrik
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB.
    Rodushkin, Ilia
    ALS Laboratory Group, ALS Scandinavia AB.
    Porcelli, Don
    Department of Earth Sciences, University of Oxford.
    Iron isotope pathways in the boreal landscape: Role of the riparian zone2018Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 239, s. 49-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stable Fe isotope compositions have been measured in water samples of the subarctic Kalix River, a first-order stream, and soil water samples from a riparian soil profile adjacent to the first-order stream (Northern Sweden). In the first-order stream, dominated by forest, both the particulate (>0.22 µm) and dissolved (<0.22 µm) phase showed negative δ56Fe values (relative to IRMM-014) during base flow and meltwater discharge in May (−0.97 to −0.09‰). The Fe isotope composition in the water from the riparian soil profile varied between −0.20 and +0.91‰ with sharp gradients near the groundwater table. A linear correlation between the δ56Fe values and the TOC/Febulk ratio was measured during snowmelt in the unfiltered river waters (δ56Fe from −0.02 to +0.54‰), suggesting mixing of two Fe components. Two groups of Fe aggregates, with different Fe isotope compositions, are formed in the boreal landscape. We propose that carbon-rich aggregates, Fe(II)(III)-OC, have negative δ56Fe values and Fe-oxyhydroxides have positive δ56Fe values. A mixture of these two components can explain temporal variations of the Fe isotope composition in the Kalix River. This study suggests that stable Fe isotopes can be used as a tool to track and characterize suspended Fe-organic carbon aggregates during transport from the soil, via first-order streams and rivers, to coastal sediment. Furthermore, the differences in Fe isotope values in the Kalix River and the first-order stream during base flow conditions suggest that the primary Fe sources for river water change throughout the year. This model is combining the Fe isotope composition of first-order streams and rivers to weathering and transport processes in the riparian soil.

  • 4.
    Pallavicini, Nicola
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden.
    Baxter, Douglas C.
    ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Hawley, Scott
    Department of Earth Sciences, Durham University, Durham, UK.
    Hirst, Catherine
    Department of Geosciences, Natural History Museum, Stockholm, Sweden.
    Rodushkina, Katerina
    Department of Chemistry, Uppsala University, Uppsala, Sweden.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Laboratory Group, ALS Scandinavia AB, Luleå, Sweden.
    Ranges of B, Cd, Cr, Cu, Fe, Pb, Sr, Tl, and Zn Concentrations and Isotope Ratios in Environmental Matrices from an Urban Area2018Ingår i: Journal of Spectroscopy, ISSN 2314-4920, E-ISSN 2314-4939, s. 1-17, artikel-id 7408767Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Isotopic information may provide powerful insight into the elemental cycling processes which occur in natural compartments. Further implementation of isotopic techniques in natural sciences requires a better understanding of the range of elemental and isotopic compositional variability in environmental matrices. This study assesses the local-scale concentration and isotopic composition variability of nine elements: boron (B), cadmium (Cd), chromium (Cr), copper (Cu), iron (Fe), lead (Pb), strontium (Sr), thallium (Tl), and zinc (Zn) in lysimetric waters, mushrooms, litter, needles, leaves, and lichens. Sequential extractions were also performed on soil samples from 6 depth profiles providing more detailed information on the variability of elemental concentrations and isotope ratios between the elemental pools present in soil. For most of the sample types studied the range of isotopic variability between samples spans almost the entire ranges reported in the literature for natural samples. These results represent a starting point for discussing the role of natural variability in isotopic studies (for example, as a limiting factor in the use of isotopic mixing models) and a baseline for future in-depth studies examining the controls on isotope fraction in natural systems

  • 5.
    Rodushkin, Ilia
    et al.
    ALS Scandinavia AB.
    Pallavicini, Nicola
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    ALS Scandinavia AB.
    Sörlin, Dieke
    ALS Scandinavia AB.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas C.
    ALS Scandinavia AB.
    Assessment of the natural variability of B, Cd, Cu, Fe, Pb, Sr, Tl and Zn concentrations and isotopic compositions in leaves, needles and mushrooms using single sample digestion and two-column matrix separation2016Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 31, nr 1, s. 220-233Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An analytical procedure allowing multi-elemental analyses and isotope ratio measurements of eight of these (B, Cd, Cu, Fe, Pb, Sr, Tl and Zn) in matrices relevant for bio-monitoring using a single highpressure acid digestion was developed. Method blanks, separation efficiency of matrix elements, repeatability and reproducibility were evaluated using sets of preparation blanks, certified reference materials and duplicate samples prepared and analyzed over a period of several months. The method was used to assess the natural variability of concentrations and isotopic compositions in bio-indicators (tree leaves, needles and mushrooms, over 240 samples) collected mainly from a confined area in North-East Sweden. Ranges found from leaves and needles were compared with data obtained for limited numbers of samples collected in Spain, Italy, France, United Kingdom and Iceland.

  • 6.
    Pontér, Simon
    et al.
    Department of Environmental Science and Analytical Chemistry, ACES, Stockholm University.
    Pallavicini, Nicola
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    ALS Scandinavia AB.
    Rodushkin, Ilia
    Chromium isotope ratio measurements in environmental matrices by MC-ICP-MS2016Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 31, nr 7, s. 1464-1471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An analytical procedure consisting of high pressure/temperature acid digestion using an UltraCLAVE system and a one pass, single column matrix separation using DOWEX AG 1X8 anion exchange resin was applied to the determination of Cr concentrations and δ53Cr in chromites, soils, and biological matrices (epiphytic lichens and mosses) using a combination of ICP-SFMS and MC-ICP-MS. The overall reproducibility of the method was assessed by replicate preparation and Cr isotope ratio measurements performed by different operators in multiple analytical sessions over a few months and was found to be 0.11‰ (2σ). The accuracy was evaluated using commercially available reference materials for which measured data were compared with certified values (for Cr concentrations) and previously published results (for isotope data). The results demonstrate a uniform Cr isotope composition in soil depth profiles sampled in different urban environments. A strong negative correlation between δ53Cr and Cr concentrations in lichens and mosses indicates that airborne Cr from local anthropogenic source(s) is depleted in heavy isotopes.

  • 7.
    Pallavicini, Nicola
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas C.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rodushkin, Ilya
    Cadmium isotope ratio measurements in environmental matrices by MC-ICP-MS2014Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 29, nr 9, s. 1570-1584Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Various stages of an analytical method for high-precision cadmium (Cd) isotope ratio measurements by MC-ICP-MS (sample preparation, matrix separation, instrumental analysis and data evaluation) were critically evaluated and optimized for the processing of carbon-rich environmental samples. Overall reproducibility of the method was assessed by replicate preparation and Cd isotope ratio measurements in various environmental matrices (soil, sediment, Fe-Mn nodules, sludge, kidney, liver, leaves) and was found to be better than 0.1‰ (2σ for δ114Cd/110Cd) for the majority of samples. Cd isotope ratio data for several commercially-available reference materials are presented and compared with previously published results where available. The method was used in a pilot study focusing on the assessment of factors affecting Cd isotope composition in tree leaves. A summary of results obtained for a large number (n > 80) of birch (Betula pubescenes) leaves collected from different locations in Sweden and through the entire growing season is presented and potential reasons for observed variability in Cd isotope composition are discussed. Seasonal dynamics of element concentrations and isotope compositions in leaves were also compared for Os, Pb, Zn and Cd.

  • 8.
    Rodríguez, Nathalie Pérez
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Langella, Francesca
    Institute for Microbiology, Friedrich-Schiller-University, Jena.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Kothe, Erika
    Institute for Microbiology, Friedrich-Schiller-University, Jena.
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    The role of bacterial consortium and organic amendment in Cu and Fe isotope fractionation in plants on a polluted mine site2014Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 21, nr 11, s. 6836-6844Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Copper and iron isotope fractionation by plant uptake and translocation is a matter of current research. As a way to apply the use of Cu and Fe stable isotopes in the phytoremediation of contaminated sites, the effects of organic amendment and microbial addition in a mine spoiled soil seeded with Helianthus annuus in pot experiments and field trials were studied. Results show that the addition of a microbial consortium of ten bacterial strains has an influence on Cu and Fe isotope fractionation by the uptake and translocation in pot experiments, with an increase in average of 0.99‰ for the δ65Cu values from soil to roots. In the field trial, the amendment with the addition of bacteria and mycorrhiza as single and double inoculation enriches the leaves in 65Cu compared to the soil. As a result of the same trial, the δ56Fe values in the leaves are lower than those from the bulk soil, although some differences are seen according to the amendment used. Siderophores, possibly released by the bacterial consortium, can be responsible for this change in the Cu and Fe fractionation. The overall isotopic fractionation trend for Cu and Fe does not vary for pots and field experiments with or without bacteria. However variations in specific metabolic pathways related to metal-organic complexation and weathering can modify particular isotopic signatures.

  • 9.
    Pallavicini, Nicola
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ecke, Frauke
    Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    ALS Scandinavia AB.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    A high-throughput method for the determination of Os concentrations and isotope ratio measurements in small-size biological samples2013Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 28, nr 10, s. 1591-1599Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An analytical method allowing multi-element characterization by external calibration, osmium (Os) concentration determination by isotope dilution (ID) and 187Os/188Os isotope abundance ratio measurement from a single sample preparation was developed. The method consists of microwave-assisted, closed-vessel acid digestion of small (0.01-0.4 g dry weight) biological samples spiked with Os solution enriched in a 190Os isotope followed by concentration and Os isotope ratio measurements using double-focusing, sector field inductively coupled plasma mass-spectrometry (ICP-SFMS) operated with methane addition to the plasma and solution nebulization (SN) sample introduction. For samples with Os content below 500 pg, complementary analysis using gas-phase introduction (GPI) on the remaining sample digests was performed. The use of disposable plastic lab ware for sample digestion and analysis by SN ICP-SFMS circumvents Os carry-over effects and improves the sample throughput and cost-efficiency of the method. For a 0.1 g dried sample, Os method limits of detection (MLODs) of 2 pg g -1 and 0.2 pg g-1 were obtained using SN or GPI, respectively. Long-term reproducibility of 187Os/188Os isotope abundance ratio measurements using the GPI approach was better than 1.5% RSD for our in-house control sample (moose kidney) with an Os concentration of approximately 5 pg g-1. Os data for several commercially available reference materials of biological or plant origin (not certified for Os) are presented. The method was used in the large scale bio-monitoring of free-living bank voles from an area affected by anthropogenic Os emissions.

  • 10.
    Rodríguez, Nathalie Pérez
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nason, Peter
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Alakangas, Lena
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Copper and iron isotope fractionation in mine tailings at the Laver and Kristineberg mines, northern Sweden2013Ingår i: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 32, s. 204-215Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Previous research has shown that Cu and Fe isotopes are fractionated by dissolution and precipitation reactions driven by changing redox conditions. In this study, Cu isotope composition (65Cu/63Cu ratios) was studied in profiles through sulfide-bearing tailings at the former Cu mine at Laver and in a pilot-scale test cell at the Kristineberg mine, both in northern Sweden. The profile at Kristineberg was also analysed for Fe isotope composition (56Fe/54Fe ratios). At both sites sulfide oxidation resulted in an enrichment of the lighter Cu isotope in the oxidised zone of the tailings compared to the original isotope ratio, probably due to preferential losses of the heavier Cu isotope into the liquid phase during oxidation of sulfides. In a zone with secondary enrichment of Cu, located just below the oxidation front at Laver, δ65Cu (compared to ERM-AE633) was as low as -4.35 ± 0.02‰, which can be compared to the original value of 1.31 ± 0.03‰ in the unoxidised tailings. Precipitation of covellite in the secondary Cu enrichment zone explains this fractionation. The Fe isotopic composition in the Kristineberg profile is similar in the oxidised zone and in the unoxidised zone, with average δ56Fe values (relative to the IRMM-014) of -0.58± 0.06‰ and -0.49 ± 0.05‰, respectively. At the well-defined oxidation front, δ56Fe was less negative, -0.24 ± 0.01 ‰. Processes such as Fe(II)-Fe(III) equilibrium and precipitation of Fe-(oxy)hydroxides at the oxidation front are assumed to cause this Fe isotope fractionation. This field study provides additional support for the importance of redox processes for the isotopic composition of Cu and Fe in natural systems.

  • 11.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, D.C.
    ALS Scandinavia AB.
    Isotopic analyses by ICP-MS in clinical samples2013Ingår i: Analusis, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 405, nr 9, s. 2785-2797Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This critical review focuses on inductively coupled plasma mass spectrometry (ICP-MS) based applications for isotope abundance ratio measurements in various clinical samples relevant to monitoring occupational or environmental exposure, human provenancing and reconstruction of migration pathways as well as metabolic research. It starts with a brief overview of recent advances in ICP-MS instrumentation, followed by selected examples that cover the fields of accurate analyte quantification using isotope dilution, tracer studies in nutrition and toxicology, and areas relying upon natural or man-made variations in isotope abundance ratios (Pb, Sr, actinides and stable heavy elements). Finally, some suggestions on future developments in the field are provided

  • 12. Baxter, Douglas
    et al.
    Rodushkin, Ilya
    ALS Scandinavia AB.
    Engström, Emma
    ALS Scandinavia AB.
    Isotope abundance ratio measurements by inductively coupled plasma-sector field mass spectrometry2012Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 27, nr 8, s. 1355-1381Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This tutorial reviews fundamental aspects of isotope abundance ratio measurement by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS). After a synopsis of the scope of isotope abundance ratio measurement and a summary introduction to the factors affecting precision and accuracy, attention is turned to noise sources. Detailed theory behind Poisson or counting statistics and plasma flicker noise components is given, since much of the observed imprecision can be attributed to these sources. Using single collector instruments, ion beams from different isotopes are sampled in rapid sequence, and so ratioing of the signals will be subject to fluctuations derived from intensity variations, i.e., flicker noise. It is demonstrated that flicker noise can, under specified circumstances, become the limiting factor for the attainable precision. Furthermore, the practice of partitioning dwell times, ostensibly to optimize precision based on isotopic abundances and assumed Poisson statistics, is shown to be flawed and actually requires accounting for flicker noise. In addition to random uncertainty, various offset factors may contribute to systematic error in measured isotope abundance ratios. Two of these, namely mass scale shift and spectral interferences are ameliorated using ICP-SFMS. The former is eliminated when operating under conditions providing flat-topped peaks, such that the minor drift in mass calibration typical of the technique becomes inconsequential and the intensity remains the same. Isotope abundance ratio measurements are subject to three further important offset factors. First is abundance sensitivity, which quantifies the extent of peak tailing to neighboring masses and can present a considerable source of offset. Second is mass bias, resulting from the fact that all sector field devices exhibit increasing sensitivity with ion mass, and various empirical methods used to correct for this effect are compared and contrasted. Third is detector dead time, which affects mass spectrometers equipped with ion counting systems. Although a well-understood phenomenon, all current methods for determining the dead time on the basis of experimentally measured isotope abundance ratios are likely to yield biased estimates. Finally, the capabilities of ICP-SFMS for the determination of isotope abundance ratios are placed in perspective by making a brief comparison with other techniques.

  • 13. Heghe, Lana Van
    et al.
    Engström, Emma
    Rodushkin, Ilya
    ALS Scandinavia AB.
    Isotopic analysis of the metabolically relevant transition metals Cu, Fe and Zn in human blood from vegetarians and omnivores using multi-collector ICP-mass spectrometry2012Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 27, s. 1327-1334Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-collector ICP-mass spectrometry (MC-ICP-MS) was used for the isotopic analysis of Cu, Fe and Zn, isolated from human whole blood. For chromatographic isolation of these elements, the method first described by Maréchal, Telouk and Albarède (Chem. Geol., 1999, 156, 251–273) and relying on the use of AG MP-1 strong anion exchange resin was further tailored and subsequently validated. It was shown that all three target elements could be obtained in pure form and with quantitative recovery from Seronorm whole blood reference material. MC-ICP-MS isotope ratio measurement conditions were optimized so as to avoid the influence of spectral overlap and the capabilities of several methods to correct for instrumental mass discrimination were compared. The method developed was then applied to a set of whole blood samples from supposedly healthy volunteers (reference population). For Fe, the by now well-known difference in isotopic composition between blood from male and female individuals was confirmed. The isotopic composition of Zn in whole blood was assessed to be governed by the diet as a significant difference could be established between blood from vegetarians and from omnivores, respectively. For the isotopic composition of Cu, interpretation of the results is more challenging, as neither gender, nor diet seems to have a significant influence, but the combined influence of both factors may show an effect.

  • 14.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    ALS Scandinavia AB.
    Engström, Emma
    Hoogewerff, J.
    Centre for Forensic Provenancing, School of Chemistry University of East Anglia, Norwich.
    Horn, P.
    München University.
    Papesch, W.
    Austrian Research Center Seibersdorf (ARCS).
    Watling, J.
    Centre for Forensic Science, University of Western Australia, Perth.
    Latkoczy, C.
    Swiss Federal Institute of Technology (ETH).
    Peijl, G. van der
    Netherlands Forensic Institute, The Hague.
    Berends-Montero, S.
    Netherlands Forensic Institute, The Hague.
    Ehleringer, J.
    University of Utah, Biology Department.
    Zdanowicz, V.
    Bureau of Customs and Border Protection, 7501 Boston Boulevard, Springfield.
    Elemental and isotopic characterization of cane and beet sugars2011Ingår i: Journal of Food Composition and Analysis, ISSN 0889-1575, E-ISSN 1096-0481, Vol. 24, nr 1, s. 70-78Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An interlaboratory program designed to assess the feasibility of using multi-element and isotopic measurements for determining the geographic origin of sugars permitted an intercomparison of the performance (in terms of limits of detection, reproducibility and bias) of various analytical techniques: inductively coupled plasma (ICP)-optical emission spectrometry (OES); different variations of ICP-mass spectrometry (MS): quadrupole (QMS), sector-field (SFMS) and multi-collector (MC-ICP-MS); thermal ionization MS (TIMS); and isotope ratio MS (IRMS). These various methods were applied to cane (raw and refined) and beet (refined) sugars from different origins. Concentrations of 63 elements and isotope ratios of Pb, Sr and C in sugar samples are reported. Determining the geographic origin of sugars appears feasible using elemental fingerprinting

  • 15.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Inorganic constituents of nuts and seeds2011Ingår i: Nuts and Seeds in Health and Disease Prevention, Elsevier, 2011, s. 65-72Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    This chapter presents data on the inorganic components of hazelnuts, walnuts, almonds, pecans, cashews, Brazil nuts, pistachios, pine nuts, peanuts, coconuts, pumpkin seeds, and sunflower seeds. Based on average consumption data for nuts and seeds, their nutritional significance and toxicological relevance in dietary intake are discussed.

  • 16.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Sörlin, Dieke
    ALS Scandinavia AB.
    Baxter, Douglas
    ALS Scandinavia AB.
    Hörnfeldt, Birger
    Swedish University of Agricultural Sciences, Department of Wildlife, Fish and Environmental Studies.
    Nyholm, Erik
    Department of Ecology and Environmental Science, Umeå University.
    Ecke, Frauke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Uptake and accumulation of anthropogenic Os in free-living bank voles (Myodes glareolus)2011Ingår i: Water, Air and Soil Pollution, ISSN 0049-6979, E-ISSN 1573-2932, Vol. 218, nr 1-4, s. 603-610Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Osmium tetroxide (OsO4) is one of the most toxic air contaminants but its environmental effects are poorly understood. Here, for the first time, we present evidence of osmium uptake in a common herbivore (bank vole, Myodes glareolus) in boreal forests of northern Sweden. Voles (n = 22) and fruticose arboreal pendular lichens, the potential main winter food source of the vole, were collected along a spatial gradient to the west of a steelwork in Tornio, Finland at the Finnish-Swedish border. 187Os/188Os isotope ratios increased and osmium concentrations decreased in lichens and voles along the gradient. Osmium concentrations in lichens were 10,000-fold higher than those in voles. Closest to the steelwork, concentrations were highest in kidneys rather than skin/fur that are directly exposed to airborne OsO4. The kidney-to-body weight ratio was higher at the two localities close to the steelwork. Even though based on a small sample size, our results for the first time demonstrate that osmium is taken up, partitioned, and accumulated in mammal tissue, and indicate that high kidney-to-body weight ratios might be induced by anthropogenic osmium.

  • 17.
    Boman, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Rodushkin, Ilya
    ALS Scandinavia AB.
    Åström, E.M.
    Linnaeus University, School of Natural Sciences, Kalmar.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fe and Zn isotopic variations in Finnish acid sulfate soils2010Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, nr 12/ Suppl 1, s. A102-Artikel i tidskrift (Övrigt vetenskapligt)
  • 18.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fractionation of the stable silicon isotopes studied using MC-ICP-MS: analytical method developments and applications in geochemistry2010Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

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

  • 19. Boman, Anton
    et al.
    Engström, Emma
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Åström, Mats
    Linnéuniversitetet.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Isotopic variations of Fe and Zn in Finnish acid sulfate soils2010Ingår i: Proceedings of the 19th World Congress of Soil Science: Soil Solutions for a Changing World / [ed] RJ Gilkes; N Prakongkep, 2010, s. 1-4Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of a Neptune high-resolution MC-ICP-MS (Thermo Fisher Scientific) in this study has enabled high precision measurements of Fe and Zn isotopic ratios in Finnish acid sulfate soils in one near shore area (Vassor) and one inland area (Rintala).

  • 20.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Baxter, Douglas
    Sources of contamination and remedial strategies in the multi-elemental trace analysis laboratory2010Ingår i: Analusis, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 396, nr 1, s. 365-377Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    In theory, state of the art inductively coupled plasma mass spectrometry (ICP-MS) instrumentation has the prerequisite sensitivity to carry out multi-elemental trace analyses at sub-ng L-1 to sub-pg L-1 levels in solution. In practice, constraints mainly imposed by various sources of contamination in the laboratory and the instrument itself, and the need to dilute sample solutions prior to analysis ultimately limit detection capabilities. Here we review these sources of contamination and, wherever possible, propose remedial strategies that we have found efficacious for ameliorating their impact on the results of multi-elemental trace analyses by ICP-MS. We conclude by providing a list of key points to consider when developing methods and preparing the laboratory to routinely meet the demands of multi-elemental analyses at trace analytical levels by ICP-MS.

  • 21.
    Engström, Emma
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Baxter, Douglas
    Ecke, Frauke
    Österlund, Helene
    Öhlander, Björn
    Temporal isotopic variations of dissolved silicon in a pristine boreal river2010Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 271, nr 3-4, s. 142-152Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 22.
    Ingri, Johan
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Gelting, Johan
    Nordblad, Fredrik
    Engström, Emma
    Rodushkin, Ilya
    Andersson, P.S.
    Oxford University.
    Porcelli, D.
    Oxford University.
    Gustafsson, O.
    Stockholms Universitet.
    Semiletov, I.
    University of Alaska.
    Öhlander, Björn
    Fractionation of iron isotopes during estuarine mixing in Ob, Yenisey and Lena freshwater plumes2009Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, nr 13, Suppl. S, s. A569-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Iron isotopes were measured in suspended matter (>0.2 µm) in the Ob, Yenisey and Lena River freshwater plumes during the International Siberian Shelf Study 2008 (ISSS-08). The δ56Fe value was around zero within the Lena River and close to the river mouth, but changed to more negative values in the outer parts of the plume. In both the Ob and Yenisey plumes suspended matter in the surface water had clearly negative values whereas samples close to the bottom showed values close to zero.It has previously been suggested that total Fe in river suspended matter (>0.2µm) in boreal regions is roughly a mixture of three phases, detrital particles (δ56Fe around zero), oxyhydroxide particles (δ56Fe positive) and C-Fe particles (δ56Fe negative). We suggest that the δ56Fe pattern observed in this study is the result of relatively rapid removal of detrital particles and Fe-oxyhydroxides, leaving a suspended fraction with negative values in the surface water in the outer parts of the freshwater plumes. Hence, during estuarine mixing of suspended particles heavy iron isotopes are deposited close to the river mouth, whereas light isotopes are exported to open ocean water.

  • 23.
    Ecke, Frauke
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Rentz, Ralf
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Husson, Eva
    Sediment and water interactions with macrophyte element concentrations and community structure2009Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

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

  • 24.
    Nordblad, Fredrik
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rodushkin, Ilya
    Engström, Emma
    Ecke, Frauke
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Ingri, Johan
    Stream water geochemistry of boron and boron isotopes in a small boreal catchment affected by a major forest fire2009Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, nr 13, Supp. S, s. A952-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

    Previous research [1] has suggested that the boron (B) isotope system has a potential to be used as a tracer for detecting historic wood fire events. It was hypothesized that highly elevated B concentrations in sediments of a lake, accompanied by an enrichment of 10B, were a result of an urban wood fire event in the 19th century. The δ11B decrease in these sediments exceeded 9 ., coinciding with a peak in the B concentration.To evaluate this hypothesis, seasonal isotopic pattern of boron (B) was investigated during spring and summer 2007 in a small stream draining a boreal forest area which was severely burnt in a major forest fire in the summer of 2006. Dissolved (< 0.22 µm) boron concentrations of the burnt area were significantly higher compared to a non-burnt reference stream, while 11B/10B ratios were significantly lower. Dissolved δ11B differences between the reference and the burnt area stream were found to be -9 to -22 .. We interpret the elevated B concentrations, accompanied by enrichment of 10B, in the burnt stream as wood and plant ash leaching of biogenic B from the burnt forest by surface run-off. Our results suggest that a boreal forest fire event significantly increases the leached amount of isotopically lighter B in the dissolved phase of stream run-off.[1] Peltola & Åström (2006), Appl. Geochem. 21 (2006) 941-948.

  • 25. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ingri, Johan
    Baxter, Douglas
    Ecke, Frauke
    Österlund, Helene
    Öhlander, Björn
    Temporal isotopic variations of dissolved silicon in a pristine boreal river2009Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 73, nr 13, Suppl. S, s. A333-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

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

  • 26.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Sörlin, D.
    ALS Scandinavia AB.
    Baxter, Douglas
    Levels of inorganic constituents in raw nuts and seeds on the Swedish market2008Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 392, nr 2-3, s. 290-304Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The levels of approximately 70 elements were determined in different culinary nuts (hazelnuts, walnuts, almonds, bitter almonds, pecans, cashews, Brazil nuts, pistachios, pine nuts, peanuts and coconuts) and seeds (pumpkin and sunflower) available on the Swedish market. The study was limited to raw, virtually unprocessed nuts and seeds (both shelled and unshelled) excluding mixed, roasted or salted products. In total, 44 products from different suppliers were analyzed, with the number of samples per nut/seed variety reflecting the availability of unprocessed products in retail outlets, varying from two for bitter almonds and pistachios to six for hazelnuts and walnuts. This selection includes samples from at least 11 different countries of origin. The optimized analytical procedure consists of microwave-assisted sample digestion using a HNO3/HF mixture, followed by multi-elemental analysis by double focusing, sector field inductively coupled plasma mass spectrometry. The analyses were accompanied by rigorous quality control measures including thorough control of potential sample contamination at all analytical stages, participation in inter-laboratory performance assessment schemes, and the analysis of certified reference materials of plant origin. Concentrations thus obtained were compared with data from product labels (where available), food composition tables and other relevant surveys, demonstrating, depending on the elements in question, close agreement as well as considerable differences.

  • 27. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Öhlander, Björn
    Ingri, Johan
    Baxter, Douglas
    Silicon isotopic composition of boreal forest vegetation in Northern Sweden2008Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 257, nr 3-4, s. 247-256Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 28.
    Reynolds, Ben C.
    et al.
    IGMR, Erdwissenschaften, ETH Zürich.
    Aggarwal, Jugdeep
    Keck Isotope Laboratory, Department of Earth Sciences, University of California.
    Andre, Luc
    Department of Geology, Musée Royal de l'Afrique Centrale, Leuvensesteenweg.
    Baxter, Douglas
    Beucher, Charlotte
    Department of Ecology Evolution and Marine Biology, Marine Science Institute, University of California.
    Brzezinski, Mark A.
    Department of Ecology Evolution and Marine Biology, Marine Science Institute, University of California.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Georg, R. Bastian
    IGMR, Erdwissenschaften, ETH Zürich.
    Land, Magnus
    Department of Geology and Geochemistry, Laboratory for Isotope Geology, Stockholm University.
    Leng, Melanie J.
    NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham.
    Opfergelt, Sophie
    Department of Geology, Musée Royal de l'Afrique Centrale, Leuvensesteenweg.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Sloane, Hilary J.
    NERC Isotope Geosciences Laboratory, British Geological Survey, Keyworth, Nottingham.
    Boorn, Sander H. J. M. van den
    Department of Earth Sciences, Utrecht University.
    Vroon, Pieter Z.
    Department of Petrology, FALW, Vrije Universiteit, De Boelelaan.
    Cardinal, Damien
    Department of Geology, Musée Royal de l'Afrique Centrale, Leuvensesteenweg.
    An inter-laboratory comparison of Si isotope reference materials2007Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 22, nr 5, s. 561-568Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Three Si isotope materials have been used for an inter-laboratory comparison exercise to ensure reproducibility between international laboratories investigating natural Si isotope variations using a variety of chemical preparation methods and mass spectrometric techniques. These proposed standard reference materials are (i) IRMM-018 (a SiO2 standard), (ii) Big-Batch (a fractionated SiO2 material prepared at the University of California Santa Barbara), and (iii) Diatomite (a natural diatomite sample originally deposited as marine biogenic opal). All analyses are compared with the international Si standard NBS28 (RM8546) and are in reasonable agreement (<+/- 0.22 parts per thousand. 1 sigma(SD) delta Si-30) given the different measurement techniques involved. These methods include both acid and alkaline dissolution/fusion, Si separation using cation exchange, selective co-precipitation, and gas-source versus plasma-ionization (high and low resolution) mass-spectrometric techniques. The average delta Si-30 for Diatomite, IRMM-018, and Big-Batch are + 1.26 parts per thousand, -1.65 parts per thousand and -10.48 parts per thousand, respectively, with corresponding delta Si-9 values of + 0.64 parts per thousand, -0.85 parts per thousand and -5.35 parts per thousand for the same standards, respectively. For the most fractionated standard (Big-Batch), results demonstrate a kinetic mass-dependent fractionation effect for atomic Si (i.e., delta Si-29 similar to 0.51 x delta Si-30). There is almost no statistical difference between the mean values obtained by each participating laboratory, with the notable exception of the IRMM-018 standard. This effect could be caused by heterogeneity or contamination of this standard. The results for the other two standards indicate that data sets produced using any of the methods employed in this study will have similar precision and differences are limited to 0.2 parts per thousand in mean delta Si-30 values for a given sample between laboratories, or differences of 0.13 parts per thousand. in mean delta Si-29 values.

  • 29.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Bergman, T.
    BD Fisk AB, Luleå.
    Douglas, G.
    Kalix kommun, Kalix.
    Engström, Emma
    Sörlin, D.
    ALS Analytica AB, Luleå.
    Baxter, Douglas
    Authentication of Kalix (NE Sweden) vendace caviar using inductively coupled plasma-based analytical techniques: evaluation of different approaches2007Ingår i: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 583, nr 2, s. 310-318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different analytical approaches for origin differentiation between vendace and whitefish caviars from brackish- and freshwaters were tested using inductively coupled plasma double focusing sector field mass spectrometry (ICP-SFMS) and multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). These approaches involve identifying differences in elemental concentrations or sample-specific isotopic composition (Sr and Os) variations. Concentrations of 72 elements were determined by ICP-SFMS following microwave-assisted digestion in vendace and whitefish caviar samples from Sweden (from both brackish and freshwater), Finland and USA, as well as in unprocessed vendace roe and salt used in caviar production. This data set allows identification of elements whose contents in caviar can be affected by salt addition as well as by contamination during production and packaging. Long-term method reproducibility was assessed for all analytes based on replicate caviar preparations/analyses and variations in element concentrations in caviar from different harvests were evaluated. The greatest utility for differentiation was demonstrated for elements with varying concentrations between brackish and freshwaters (e.g. As, Br, Sr). Elemental ratios, specifically Sr/Ca, Sr/Mg and Sr/Ba, are especially useful for authentication of vendace caviar processed from brackish water roe, due to the significant differences between caviar from different sources, limited between-harvest variations and relatively high concentrations in samples, allowing precise determination by modern analytical instrumentation. Variations in the 87Sr/86Sr ratio for vendace caviar from different harvests (on the order of 0.05-0.1%) is at least 10-fold less than differences between caviar processed from brackish and freshwater roe. Hence, Sr isotope ratio measurements (either by ICP-SFMS or by MC-ICP-MS) have great potential for origin differentiation. On the contrary, it was impossible to differentiate between Swedish caviar processed from brackish water roe and Finnish freshwater caviar based solely on 187Os/188Os ratios.

  • 30.
    Engström, Emma
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Ingri, Johan
    Öhlander, Björn
    Characterization of the silicon isotopic composition of the terrestrial biogenic output from a boreal forest in Northern Sweden2007Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 71, nr 15s, s. A256-Artikel i tidskrift (Övrigt vetenskapligt)
    Abstract [en]

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

  • 31.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Baxter, Douglas
    Evaluation of simultaneous analyte leaching/vapour phase introduction for direct os isotope ratio measurements in solid samples by double focusing sector field ICP-MS2007Ingår i: Geostandards and Geoanalytical Research, ISSN 1639-4488, E-ISSN 1751-908X, Vol. 31, nr 1, s. 27-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The analytical performance of a hyphenated method for Os isotope ratio measurements by double focusing, sector field ICP-MS (ICP-SFMS) was evaluated. The method is based on several optimised, concurrent processes: Os extraction from samples in hot concentrated nitric acid; separation of Os from the digest solution by formation of volatile osmium tetroxide accelerated by continuous hydrogen peroxide addition; transport of analyte vapour by an oxygen flow into the ICP; and isotopic analysis by ICP-SFMS. Due to the very efficient analyte utilisation (in excess of 0.5‰), isotope ratio measurement can be performed at low pg Os levels. Combined with the ability to process sample sizes up to 2 g (up to 50 g if the organic matrix of biological or botanical samples is eliminated by ashing), materials with Os concentrations in the low, or even sub-pg g-1 range can be analysed by the method. Given that two complete digestion/distillation systems are available for interchangeable use, throughputs of up to 15 samples per 8-hour shift can be achieved. The method precision, evaluated as the long-term reproducibility of 187Os/188Os ratio measurements in a commercial Os standard containing 0.5 ng Os, was 0.16% relative standard deviation (RSD, 1 s). The method has been applied to perform replicate 187Os/188Os ratio measurements in a suite of 50 reference materials of various origins and matrix compositions, with Os concentrations varying from <0.1 pg g-1 to >100 ng g-1, yielding an average precision of 3% RSD. Though none of the materials tested are certified for Os content or Os isotope composition, comparison of the obtained data with published Os isotope information for similar sample types revealed close agreement between the two. The method can also be used for the simultaneous, semi-quantitative approximation of Os concentrations.

  • 32.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fractionation of the stable silicon isotopes: analytical method developments and selected applications in geochemistry2007Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

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

  • 33. Engström, Emma
    et al.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Förekomst av osmium och osmiumtetroxid i Norrbottens län2007Rapport (Övrig (populärvetenskap, debatt, mm))
  • 34. Baxter, Douglas
    et al.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Klockare, Dennis
    ALS Analytica AB, Luleå.
    Waara, Hans
    ALS Analytica AB, Luleå.
    Methylmercury measurement in whole blood by isotope-dilution GC-ICPMS with 2 sample preparation methods2007Ingår i: Clinical Chemistry, ISSN 0009-9147, E-ISSN 1530-8561, Vol. 53, nr 1, s. 111-116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Despite its known toxicity, methylmercury is rarely measured directly in clinical studies; instead, conclusions are based on total mercury measurements. We have developed isotope-dilution-based methods for methylmercury-specific analysis of whole blood by coupled gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS). Methods: We analyzed animal and human blood samples after alkaline digestion or extraction of methylmercury into dichloromethane and back extraction into water. Methylmercury was converted to the volatile ethyl derivative, purged, and trapped on a solid-phase collection medium, and then introduced into the GC-ICPMS system. Results: Limits of quantification were 0.4 and 0.03 mu g/L at a signal-to-noise ratio of 10 with the alkaline digestion and extraction methods, respectively. Extraction met our selected acceptable total error criterion, with an SD of 0.58 mu g/L at the critical maternal blood concentration of 5.8 mu g/L.Results obtained with alkaline digestion indicated the need for improved random analytical uncertainty, which was achieved by increasing the enrichment of the isotope dilution. For 37 blood samples, the mean (SD) proportion of total mercury present as methylmercury was 60 (27)%, range 6%-100%.Conclusions: The combination of extraction and isotope-dilution GC-ICPMS meets the requirements for use as a reference method for measuring methylmercury in whole blood.

  • 35.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Sörlin, Dieke
    ALS Analytica AB, Luleå.
    Pontèr, Christer
    ALS Analytica AB, Luleå.
    Baxter, Douglas
    Osmium in environmental samples from Northeast Sweden: Part I. Evaluation of background status2007Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 386, nr 1-3, s. 145-158Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Osmium (Os) concentrations and 187Os/188Os isotope abundance ratios are presented for sedimentary materials, soils, humus, plants, mushrooms, mosses and lichens collected in the vicinity of the town of Luleå, Northeast Sweden, the data for biological specimens being the first reported. Contributions from sampling and varying exposure time to the observed environmental variability were evaluated. Sedimentary materials (from both fresh and brackish water) are most elevated in radiogenic 187Os, followed by inorganic soil horizons, mushrooms and humus. The Os isotopic compositions of plants, mosses and lichens are much less radiogenic, with mean 187Os/188Os lying within a relatively narrow 0.3-0.6 range. Significant temporal variations in Os concentrations and isotopic compositions of plant samples are attributed to integrative uptake of airborne Os with non-radiogenic composition. Measured Os concentrations in biological matrices increase in the order: small shrub leaves (blueberry and lingonberry) ≤ spruce needles ≤ mushrooms ≤ tree leaves ≤ pine needles < mosses lichens. The concentrations found in three different species of plant were used to provide the first estimates of gaseous osmium tetroxide (OsO4) in the environment. Though the Os content of samples from Northeast Sweden does not differ significantly from matrix-matched international reference materials (not certified for Os) of abiotic origin, the estimates of gaseous OsO4 concentrations are roughly an order of magnitude higher than have been reported for particle-bound Os in other studies. The pronounced spatial variations between relatively closely situated sites in mean 187Os/188Os ratios for samples of the same species (presumably with the same dominating uptake mechanism) point to the presence of different local Os sources. This study therefore demonstrates that emissions of Os from automobile catalytic converters are not the only source of contemporary environmental contamination.

  • 36.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Sörlin, Dieke
    ALS Analytica AB, Luleå.
    Pontér, Christer
    ALS Analytica AB, Luleå.
    Baxter, Douglas
    Osmium in environmental samples from Northeast Sweden: Part II. Identification of anthropogenic sources2007Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 386, nr 1-3, s. 159-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Osmium (Os) concentrations and 187Os/188Os isotope abundance ratios measured in epiphytic lichens from Northeast Sweden have been used for the identification of anthropogenic emission sources of this element. Based on isotope abundance ratios and similarities in spatial distributions between Os and chromium, smelters operated on chromium ores from Kemi deposits have shown to be the most important factor affecting the airborne Os burden in the region. The extent of the exposure is reflected by lichen concentrations near the source exceeding those from remote areas by a factor of 1000. Contributions from metal foundries processing iron, copper, lead and zinc ores can also be seen, though, because of lower Os concentrations in the feedstock, on a considerably lower scale. Masked by these industrial emissions in the studied area, the impact of Os originating from automotive catalytic converters cannot be resolved at present.

  • 37.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    An inter-laboratory calibration of Si isotope reference materials2006Ingår i: Vol. 70, nr 18, Suppl. 1, s. A529-Artikel i tidskrift (Refereegranskat)
  • 38.
    Engström, Emma
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Öhlander, Björn
    Chromatographic purification for the determination of dissolved silicon isotopic composition in natural waters by high-resolution multicollector inductively coupled plasma mass spectrometry2006Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 78, nr 1, s. 250-257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 39. Baxter, Douglas
    et al.
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Malinovskiy, Dmitry
    Revised exponential model for mass bias correction using an internal standard for isotope abundance ratio measurements by multi-collector inductively coupled plasma mass spectrometry2006Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 21, nr 4, s. 427-430Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An internal standard (IS) can be used to account for moderate, matrix-related shifts in mass bias using multi-collector inductively coupled plasma mass spectrometry through the empirical, linear relationship between measured isotope abundance ratios for different elements in ln-ln space. Unfortunately, erroneous mass bias corrected isotope abundance ratios may be returned by the model, requiring artificial adjustment of the true isotope abundance ratio of the IS. Although inadequate correction for peak tailing has been convincingly used to explain this problem, our analysis of the literature describing the development of the mass bias correction model using an IS reveals the presence of a source of systematic error. The origin of this error is purely mathematical and is eliminated in the revised model presented, in which mass bias corrected isotope abundance ratios are independent of the isotopic composition of the IS. An expression for computing the total combined uncertainty in the corrected ratio, incorporating contributions from the linear model, the isotopic reference material, and measurements of analyte element and IS in the sample, is also derived.

  • 40.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Baxter, Douglas
    Tracing Os pollution sources using isotope signatures2006Ingår i: 3rd Nordic conference on plasma spectrochemistry: plasma spectrochemical abstracts, Amherst, Mass: ICP Information Newsletter, Inc , 2006Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    A hyphenated method for Os isotope ratio measurements by double focusing, sector field ICP-MS (ICP-SFMS) was developed. The method is based on several optimised, concurrent processes: Os extraction from samples in hot concentrated nitric acid; separation of Os from the digest solution by formation of volatile osmium tetroxide accelerated by continuous hydrogen peroxide addition; transport of analyte vapour by an oxygen flow into the ICP; and isotopic analysis by ICP-SFMS. Due to the very efficient analyte utilisation (in excess of 0.5‰), isotope ratio measurement can be performed at low pg Os levels. Combined with the ability to process sample sizes up to 2 g (up to 50 g if the organic matrix of biological or botanical samples is eliminated by ashing), materials with Os concentrations in the low, or even sub-pg g-1 range can be analysed by the method. This ability was used to measure Os concentrations and isotope ratios in variety of environmental and geological materials. Based on the data, it was possible to trace both long-range and local Os emission sources.

  • 41.
    Rodushkin, Ilia
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Nordlund, Peter
    Analytica AB.
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Improved multi-elemental analyses by inductively coupled plasma-sector field mass spectrometry through methane addition to the plasmat2005Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 20, nr 11, s. 1250-1255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Changes in the analytical performance of double focusing sector field inductively coupled plasma mass spectrometry (ICP-SFMS) caused by addition of methane to the argon gas ICP were studied for approximately 100 isotopes of 70 elements. The parameters under consideration included instrumental background, analyte sensitivity, precision and formation of spectral interferences as functions of methane flow added to the sample gas. It was shown that for many analytes the capabilities of ICP-SFMS significantly improve by virtue of enhanced sensitivity and reduction of polyatomic interferences. In contrast to quadrupole-based ICP-MS, these gains in instrumental performance do not compromise multi-element capabilities given that the amount of methane is carefully optimized. The accuracy of the results for the determination of 50 elements in water samples was evaluated using the certified reference materials SLRS-4 and SLEW-2.

  • 42.
    Stenberg, Anna
    et al.
    Luleå tekniska universitet.
    Malinovskiy, Dmitry
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Andren, Henrik
    Forsling, Willis
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Engström, Lena-Maria
    Umeå universitet.
    Wahlin, Anders
    Umeå universitet.
    Engström, Emma
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Measurement of iron and zinc isotopes in human whole blood: preliminary application to the study of HFE genotypes2005Ingår i: Journal of Trace Elements in Medicine and Biology, ISSN 0946-672X, E-ISSN 1878-3252, Vol. 19, nr 1, s. 55-60Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Multi-collector inductively coupled plasma - sector field mass spectrometry was applied to the measurement of Fe and Zn isotopes in human whole blood samples. For the Fe present in the blood of healthy adults, enrichment of the lighter isotopes relative to a standard material was observed, in agreement with earlier studies. The level of fractionation was found to be lower in hemochromatosis patients exhibiting homozygous (C282Y/C282Y) mutation of the HFE gene. On the one hand, this reinforces the hypothesis that Fe fractionation in blood decreases with enhanced dietary absorption. On the other hand, this contradicts predictions made on the basis of determinations of Fe fractionation in blood samples collected from subjects characterized by milder HFE mutations. In healthy subjects, the Zn in blood is depleted in lighter isotopes, consistent with the limited number of prior observations. As for Fe, the Zn isotopic composition exhibited a tendency toward lower levels of fractionation in the blood of subjects with hereditary hemochromatosis with homozygous mutation (C282Y/C282Y) of the HFE gene. The results therefore suggest that both Fe and Zn isotopic signatures in whole blood, at least to some extent, reflect polymorphisms in the HFE gene.

  • 43.
    Rodushkin, Ilya
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Stenberg, Anna
    Luleå tekniska universitet.
    Baxter, Douglas
    Determination of low-abundant elements at ultra-trace levels in urine and serum by inductively coupled plasma mass spectrometry2004Ingår i: Analusis, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 380, nr 2, s. 247-257Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A procedure is described for the determination of Y, Zr, Nb, Ru, Rh, Pd, Ag, SB, Te, Hf, Ta, W, Re, Os, Ir, Pt, An, Tl, Bi, and U in human urine and serum at concentrations relevant to the occupationally unexposed population. Sample preparation was limited to tenfold dilution with 2% HCl. A combination of a sample introduction system designed to provide enhanced sensitivity and the use of water and acids of high-purity has resulted in limits of quantification (LOQ) in the sub-nanogram per liter range for 13 analytes. Instrumental background caused by release of analytes (Y, Zr, Ag, Sb, Au, Tl, Bi, U) from different parts of the sample-introduction system was found to be the major limitation in obtaining better LOQ. Nevertheless, detection capabilities of the proposed procedure were adequate for all elements except Ru, Pd, and Rh. Despite the use of high-resolution mode for these analytes some unresolved spectral interferences might still be present. For 13 elements an external accuracy assessment was accomplished by participating in proficiency testing and inter-comparison programs. Results obtained for pooled urine and serum were compared with concentrations reported for occupationelly unexposed populations in recent publications.

  • 44.
    Engström, Emma
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Stenberg, Anna
    Luleå tekniska universitet.
    Baxter, Douglas
    Malinovskiy, Dmitry
    Irma, Mäkinen
    Finnish Environment Institute.
    Pönni, Seppo
    Pirkanmaa Regional Environment Centre.
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Effects of sample preparation and calibration strategy on accuracy and precision in the multi-elemental analysis of soil by sector field ICP-MS2004Ingår i: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 19, s. 858-866Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 45.
    Stenberg, Anna
    et al.
    Luleå tekniska universitet.
    Andren, Henrik
    Malinovskiy, Dmitry
    Engström, Emma
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser.
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Baxter, Douglas
    Isotopic variations of Zn in biological materials2004Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, nr 14, s. 3971-3978Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Variations in the isotopic composition of Zn present in various biological materials were determined using high-resolution multicollector inductively coupled plasma mass spectrometry (MC-ICPMS), following digestion and purification by anion exchange chromatography. To correct for differences in instrumental mass discrimination effects between samples and standards, Cu was employed as an elemental spike. Complementary analyses of Zn separates by sector field ICPMS instruments revealed that the concentrations of the majority of potentially interfering elements were reduced to negligible levels. Residual spectral interferences resulting from 35Cl16O2+, 40Ar14N2+, and 40Ar14N16O+ could be instrumentally resolved from the 67Zn, 68Zn, and 70Zn ion beams, respectively, during measurement by MC-ICPMS. The only other observed interference in the Cu and Zn mass range that could not be effectively eliminated by high-resolution multicollection resulted from 35Cl2+, necessitating modification of the sample preparation procedure to allow accurate 70Zn detection. Complete duplication of the entire analytical procedure for human whole blood and hair, as well as bovine liver and muscle, provided an external reproducibility of 0.05-0.12” (2) for measured 66/64Zn, 67/64Zn, and 68/64Zn values, demonstrating the utility of the method for the precise isotopic analysis of Zn in biological materials. Relative to the selected Zn isotopic standard, 66/64Zn values for biological samples varied from -0.60” in human hair to +0.56” in human whole blood, identifying the former material as the isotopically lightest Zn source found in nature to date.

  • 46. Engström, Emma
    et al.
    Stenberg, Anna
    Luleå tekniska universitet.
    Senioukh, Svetlana
    ALS Analytica AB, Luleå.
    Edelbro, Roland
    ALS Analytica AB, Luleå.
    Baxter, Douglas
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Multi-elemental characterization of soft biological tissues by inductively coupled plasma-sector field mass spectrometry2004Ingår i: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 521, nr 2, s. 123-135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

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