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  • 1. Aamaas, Borgar
    et al.
    Boggild, Carl Egede
    Stordal, Frode
    Berntsen, Terje
    Holmen, Kim
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Elemental carbon deposition to Svalbard snow from Norwegian settlements and long-range transport2011Inngår i: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 63, nr 3, s. 340-351Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The impact on snow pack albedo from local elemental carbon (EC) sources in Svalbard has been investigated for the winter of 2008. Highly elevated EC concentrations in the snow are observed around the settlements of Longyearbyen and Svea (locally > 1000 ng g(-1), about 200 times over the background level), while EC concentrations similar to the background level are seen around Ny-Alesund. Near Longyearbyen and Svea, darkened snow influenced by wind transported coal dust from open coal stockpiles is clearly visible from satellite images and by eye at the ground. As a first estimate, the reduction in snow albedo caused by local EC pollution from the Norwegian settlements has been compared to the estimated reduction caused by long-range transported EC for entire Svalbard. The effect of local EC from Longyearbyen, Svea and all Norwegian settlements are estimated to 2.1%, 7.9% and 10% of the total impact of EC, respectively. The EC particles tend to stay on the surface during melting, and elevated EC concentrations due to the spring melt was observed. This accumulation of EC enhances the positive albedo feedbacks. The EC concentrations were observed to be larger in metamorphosed snow than in fresh snow, and especially around ice lenses.

  • 2. Abbasi, Saeed
    et al.
    Jansson, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Olander, Lars
    Olofsson, Ulf
    Sellgren, Ulf
    A pin-on-disc study of the rate of airborne wear particle emissions from railway braking materials2012Inngår i: Wear, ISSN 0043-1648, E-ISSN 1873-2577, Vol. 284, s. 18-29Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The current study investigates the characteristics of particles generated from the wear of braking materials, and provides an applicable index for measuring and comparing wear particle emissions. A pin-on-disc tribometer equipped with particle measurement instruments was used. The number concentration, size, morphology, and mass concentration of generated particles were investigated and reported for particles 10 nm-32 mu m in diameter. The particles were also collected on filters and investigated using EDS and SEM. The effects of wear mechanisms on particle morphology and changes in particle concentration are discussed. A new index, the airborne wear particle emission rate (AWPER), is suggested that could be used in legislation to control non-exhaust emissions from transport modes, particularly rail transport.

  • 3.
    Abbasi, Saeed
    et al.
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Jansson, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sellgren, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Olofsson, Ulf
    KTH Royal Inst Technol, Dept Machine Design, Stockholm, Sweden.
    Particle Emissions From Rail Traffic: A Literature Review2013Inngår i: Critical reviews in environmental science and technology, ISSN 1064-3389, E-ISSN 1547-6537, Vol. 43, nr 23, s. 2511-2544Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Particle emissions are a drawback of rail transport. This work is a comprehensive presentation of recent research into particle emissions from rail vehicles. Both exhaust and nonexhaust particle emissions are considered when examining particle characteristics such as PM10, and PM2.5 concentration levels, size, morphology, composition, and adverse health effects, current legislation, and available and proposed solutions for reducing such emissions. High concentration levels in enclosed rail traffic environments are reported and some toxic effects of the particles. The authors find that only a few limited studies have examined the adverse health effects of nonexhaust particle emissions and that no relevant legislation exists. Thus further research in this area is warranted.

  • 4. Abbasi, Saeed
    et al.
    Olander, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Larsson, Christina
    Olofsson, Ulf
    Jansson, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sellgren, Ulf
    A field test study of airborne wear particles from a running regional train2012Inngår i: Proceedings of the Institution of mechanical engineers. Part F, journal of rail and rapid transit, ISSN 0954-4097, E-ISSN 2041-3017, Vol. 226, nr 1, s. 95-109Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Inhalable airborne particles have inverse health effects. In railways, mechanical brakes, the wheel–rail contact, current collectors, ballast, sleepers, and masonry structures yield particulate matter. Field tests examined a Swedish track using a train instrumented with particle measurement devices, brake pad temperature sensors, and speed and brake sensors. The main objective of this field test was to study the characteristics of particles generated from disc brakes on a running train with an on-board measuring set-up. Two airborne particle sampling points were designated, one near a pad–rotor disc brake contact and a second under the frame, not near a mechanical brake or the wheel–rail contact; the numbers and size distributions of the particles detected were registered and evaluated under various conditions (e.g. activating/deactivating electrical brakes or negotiating curves). During braking, three speed/temperature-dependent particle peaks were identified in the fine region, representing particles 280, 350, and 600 nm in diameter. In the coarse region, a peak was discerned for particles 3–6 µm in diameter. Effects of brake pad temperature on particle size distribution were also investigated. Results indicate that the 280 nm peak increased with increasing temperature, and that electrical braking significantly reduced airborne particle numbers. Field emission scanning electron microscope images captured particles sizing down to 50 nm. The inductively coupled plasma mass spectrometry results indicated that Fe, Cu, Zn, Al, Ca, and Mg were the main elements constituting the particles.

  • 5. Abiven, Samuel
    et al.
    Hund, Andreas
    Martinsen, Vegard
    Cornelissen, Gerard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM). Norwegian University of Life Sciences (NMBU), Norway; Norwegian Geotechnical Institute (NGI), Norway .
    Biochar amendment increases maize root surface areas and branching: a shovelomics study in Zambia2015Inngår i: Plant and Soil, ISSN 0032-079X, E-ISSN 1573-5036, Vol. 395, nr 1-2, s. 45-55Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Positive crop yield effects from biochar are likely explained by chemical, physical and/or biological factors. However, studies describing plant allometric changes are scarcer, but may be crucial to understand the biochar effect. The main aim of the present study is to investigate the effect of biochar on root architecture under field conditions in a tropical setting. The presented work describes a shovelomics (i.e., description of root traits in the field) study on the effect of biochar on maize root architecture. Four field experiments we carried out at two different locations in Zambia, exhibiting non-fertile to relatively fertile soils. Roots of maize crop (Zea mays L.) were sampled from treatments with fertilizer (control) and with a combination of fertilizer and 4 t.ha(-1) maize biochar application incorporated in the soil. For the four sites, the average grain yield increase upon biochar addition was 45 +/- 14 % relative to the fertilized control (from 2.1-6.0 to 3.1-9.1 ton ha(-1)). The root biomass was approximately twice as large for biochar-amended plots. More extensive root systems (especially characterized by a larger root opening angle (+14 +/- 11 %) and wider root systems (+20 +/- 15 %)) were observed at all biochar-amended sites. Root systems exhibited significantly higher specific surface areas (+54 +/- 14 %), branching and fine roots: +70 +/- 56 %) in the presence of biochar. Biochar amendment resulted in more developed root systems and larger yields. The more extensive root systems may have contributed to the observed yield increases, e.g., by improving immobile nutrients uptake in soils that are unfertile or in areas with prolonged dry spells.

  • 6.
    Achtert, Peggy
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Tesche, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Assessing lidar-based classification schemes for polar stratospheric clouds based on 16 years of measurements at Esrange, Sweden2014Inngår i: Journal of Geophysical Research: Atmospheres, ISSN 2169-8996, Vol. 119, nr 3, s. 1386-1405Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lidar measurements of polar stratospheric clouds (PSCs) are commonly analyzed in classification schemes that apply the backscatter ratio and the particle depolarization ratio. This similarity of input data suggests comparable results of different classification schemes—despite measurements being performed with a variety of mostly custom-made instruments. Based on a time series of 16 years of lidar measurements at Esrange (68°N, 21°E), Sweden, we show that PSC classification differs substantially depending on the applied scheme. The discrepancies result from varying threshold values of lidar-derived parameters used to define certain PSC types. The resulting inconsistencies could impact the understanding of long-term PSC observations documented in the literature. We identify two out of seven considered classification schemes that are most likely to give reliable results and should be used in future lidar-based studies. Using polarized backscatter ratios gives the advantage of increased contrast for observations of weakly backscattering and weakly depolarizing particles. Improved confidence in PSC classification can be achieved by a more comprehensive consideration of the effect of measurement uncertainties. The particle depolarization ratio is the key to a reliable identification of different PSC types. Hence, detailed information on the calibration of the polarization-sensitive measurement channels should be provided to assess the findings of a study. Presently, most PSC measurements with lidar are performed at 532 nm only. The information from additional polarization-sensitive measurements in the near infrared could lead to an improved PSC classification. Coincident lidar-based temperature measurements at PSC level might provide useful information for an assessment of PSC classification.

  • 7.
    Acosta Navarro, Juan Camilo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Smolander, S.
    Struthers, H.
    Zorita, E.
    Ekman, Annica M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Kaplan, J. O.
    Guenther, A.
    Arneth, A.
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Global emissions of terpenoid VOCs from terrestrial vegetation in the last millennium2014Inngår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 119, nr 11, s. 6867-6885Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We investigated the millennial variability (1000 A.D.-2000 A.D.) of global biogenic volatile organic compound (BVOC) emissions by using two independent numerical models: The Model of Emissions of Gases and Aerosols from Nature (MEGAN), for isoprene, monoterpene, and sesquiterpene, and Lund-Potsdam-Jena-General Ecosystem Simulator (LPJ-GUESS), for isoprene and monoterpenes. We found the millennial trends of global isoprene emissions to be mostly affected by land cover and atmospheric carbon dioxide changes, whereas monoterpene and sesquiterpene emission trends were dominated by temperature change. Isoprene emissions declined substantially in regions with large and rapid land cover change. In addition, isoprene emission sensitivity to drought proved to have significant short-term global effects. By the end of the past millennium MEGAN isoprene emissions were 634 TgC yr-1 (13% and 19% less than during 1750-1850 and 1000-1200, respectively), and LPJ-GUESS emissions were 323 TgC yr-1(15% and 20% less than during 1750-1850 and 1000-1200, respectively). Monoterpene emissions were 89 TgC yr-1(10% and 6% higher than during 1750-1850 and 1000-1200, respectively) in MEGAN, and 24 TgC yr-1 (2% higher and 5% less than during 1750-1850 and 1000-1200, respectively) in LPJ-GUESS. MEGAN sesquiterpene emissions were 36 TgC yr-1(10% and 4% higher than during 1750-1850 and 1000-1200, respectively). Although both models capture similar emission trends, the magnitude of the emissions are different. This highlights the importance of building better constraints on VOC emissions from terrestrial vegetation.

  • 8.
    Adolfsson-Erici,
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Allmyr,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Antibakteriellt behandlade konsumentprodukter - källa till exponering av människa och miljö2007Rapport (Annet (populærvitenskap, debatt, mm))
  • 9.
    Adolfsson-Erici,
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Allmyr,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Andersson, H.
    Glynn, A.
    Sources of triclosan exposure to humans2007Inngår i: SETAC News: May 20-24, 2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 10.
    Adolfsson-Erici,
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Alsberg,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Magnér,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gunnarsson, L.
    Larsson, D.G.J.
    Pharmacuticals in fish bile2007Inngår i: SNMM: March 12-14 2007, 2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 11.
    Adolfsson-Erici,
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Alsberg,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Magnér,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gunnarsson, L.
    Larsson, D.G.J.
    Tracing pharmaceutical residues from humans to fish2007Inngår i: SETAC News: May 20-24, 2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 12.
    Adolfsson-Erici, M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Pettersson, M.
    Parkkonen, J.
    Sturve, J.
    Triclosan, a commonly used bactericide found in human milk and in the aquatic environment in Sweden2002Inngår i: Chemosphere, ISSN 0366-7111, Vol. 46, nr 9-10, s. 1485-1489Artikkel i tidsskrift (Fagfellevurdert)
  • 13.
    Adolfsson-Erici, Margaretha
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Fish bile in environmental analysis2005Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    This work explores the usefulness of fish bile analysis in combination with biomarkers for identifying and evaluating new environmental contaminants in the aquatic environment. It illustrates how bile analysis can be used together with biomarkers to assess the causes of estrogenic effects, to identify chemicals in the aquatic environment that are taken up by fish, and to monitor environmental exposure.

    In a first application, fish exposed to sewage treatment plant effluent were studied. Elevated levels of vitellogenin in the exposed fish demonstrated that estrogenic effects occurred. Several estrogen disrupting substances were identified in the fish bile, and analysis of water samples confirmed that these substances were present in the effluent. The synthetic estrogen 17a-ethinylestradiol, which is known to be present in sewage treatment plant effluent, was shown for the first time to be taken up by fish. Considering the reported potencies of the detected substances, it was concluded that 17a-ethinylestradiol was the major contributor to the estrogenic effects.

    Chemical analysis of bile was used to identify rubber additives that were released from tires immersed in water. The bile of rainbow trout held in the water contained high levels of metabolites of PAHs and aromatic nitrogen compounds. Several biomarkers were also measured in the exposed fish, and EROD induction and oxidative stress were observed. Based on the bile analysis observations together with knowledge of toxicological mechanisms, it was postulated that the EROD induction was due to the PAHs, while aromatic nitrogen compounds caused the oxidative stress.

    Resin acids in fish bile proved to be a good indicator of exposure in a chronic long-term study of rainbow trout exposed to effluent from a total chlorine free (TCF) pulp mill. Elevated levels of GST (gluthatione-S-transferase) and GR (gluthatione reductase) activity, and the presence of DNA adducts after a two month recovery period, indicated that compounds in the pulp mill effluents have persistent effects. In addition to characterising the exposure of the fish to the effluent, the analysis of the resin acids in the bile provided evidence of accidents in the pulp mill that the existing process monitoring system had not detected.

    Resin acids in bile were also found to be a valuable indicator of exposure to pulp mill effluents for eelpout living in the Baltic Sea. A correlation between resin acid levels in bile and skewed sex ratios provided an important link in the chain of evidence that substances in the pulp mill effluents cause male bias of the eelpout embryos.

    A particularly good example of the potential of bile analysis was the identification of a previously unknown environmental contaminant. A large peak was observed in the bile extracts of fish that had been exposed to sewage treatment plant effluent. This peak was identified as triclosan, which demonstrated its presence in sewage treatment plant effluent. Other work went on to show that it is a common contaminant of the aquatic environment. The ability of fish to concentrate contaminant metabolites in bile to levels very much higher than in the environment, and the comparatively low levels of analytic interferences, make bile a particularly attractive matrix to search for new, unknown organic pollutants

  • 14.
    Adolfsson-Erici, Margaretha
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Åkerman, Gun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Jahnke, Annika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mayer, Philipp
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    A flow-through passive dosing system for continuously supplying aqueous solutions of hydrophobic chemicals to bioconcentration and aquatic toxicity tests2012Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 86, nr 6, s. 593-599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A continuous supply of water with defined stable concentrations of hydrophobic chemicals is a requirement in a range of laboratory tests such as the OECD 305 protocol for determining the bioconcentration factor in fish. Satisfying this requirement continues to be a challenge, particularly for hydrophobic chemicals. Here we present a novel solution based on equilibrium passive dosing. It employs a commercially available unit consisting of similar to 16000 polydimethylsiloxane (PDMS) tubes connected to two manifolds. The chemicals are loaded into the unit by repeatedly perfusing it with a methanol solution of the substances that is progressively diluted with water. Thereafter the unit is perfused with water and the chemicals partition from the unit into the water. The system was tested with nine chemicals with logK(ow) ranging from 4.1 to 6.3. The aqueous concentrations generated were shown to be largely independent of the water flow rate, and the unit to unit reproducibility was within a factor of similar to 2. In continuous flow experiments the aqueous concentrations of most of the study chemicals remained constant over 8 d. A model was assembled that allows prediction of the operating characteristics of the system from the logKow or PDMS/water partition coefficient of the chemical. The system is a simple, safe, predictable and flexible tool that generates stable aqueous concentrations of hydrophobic chemicals.

  • 15.
    Adolfsson-Erici, Margaretha
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Åkerman, Gun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Internal Benchmarking Improves Precision and Reduces Animal Requirements for Determination of Fish Bioconcentration Factors2012Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, nr 15, s. 8205-8211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The enactment of new chemical regulations has generated a large need for the measurement of the fish bioconcentration factor (BCF). Past experience shows that the BCF determination lacks precision, requires large numbers of fish, and is costly. A new protocol was tested that shortens the experiment from up to 12 weeks for existing protocols to 2 weeks and reduces the number of fish by a factor of 5, while introducing internal benchmarking for the BCF determination. Rainbow trout were simultaneously exposed to 11 chemicals. The BCFs were quantified using one of the test chemicals, musk xylene, as a benchmark. These were compared with BCFs measured in a parallel experiment based on the OECD 305 guideline. The agreement was <20% for five chemicals and between 20%-25% for two further, while two chemicals lay outside the BCF operating window of the experiment and one was lost due to analytical difficulties. This agreement is better than that observed in a BCF Gold Standard Database. Internal benchmarking allows the improvement of the precision of BCF determination in parallel to large reduction in costs and fish requirements.

  • 16.
    Adolfsson-Erici, Margaretha
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Åkerman, Gun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    In-vivo passive sampling to measure elimination kinetics in bioaccumulation tests2012Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 88, nr 1, s. 62-68Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The application of in-tissue passive sampling to quantify chemical kinetics in fish bioconcentration experiments was investigated. A passive sampler consisting of an acupuncture needle covered with a PDMS tube was developed together with a method for its deployment in rainbow trout. The time to steady state for chemical uptake into the passive sampler was >1 d, so it was employed as a kinetically limited sampler with a deployment time of 2 h. The passive sampler was employed in parallel with the established whole tissue extraction method to study the elimination kinetics of 10 diverse chemicals in rainbow trout. 4-n-nonylphenol and 2,4,6-tri-tert-butylphenol were close to or below the limit of quantification in the sampler. For chlorpyrifos, musk xylene, hexachlorobenzene, 2,5-dichlorobiphenyl and p,p'-DDT. the elimination rate constants determined with the passive sampler method and the established method agreed within 18%. Poorer agreement (35%) was observed for 2,3,4-trichloroanisole and p-diisopropylbenzene because fewer data were obtained with the passive sampling method due to its lower sensitivity. The work shows that in-tissue passive sampling can be employed to measure contaminant elimination kinetics in fish. This opens up the possibility of studying contaminant kinetics in individual fish, thereby reducing the fish requirements and analytical costs for the determination of bioconcentration factors.

  • 17.
    Adolfsson-Erici, Margaretha
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Åkerman, Gun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Measuring bioconcentration factors in fish using exposure to multiple chemicals and internal benchmarking to correct for growth dilution2012Inngår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 31, nr 8, s. 1853-1860Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Modern chemical legislation requires measuring the bioconcentration factor (BCF) of large numbers of chemicals in fish. The BCF must be corrected for growth dilution, because fish growth rates vary between laboratories. Two hypotheses were tested: (1) that BCFs of multiple chemicals can be measured simultaneously in one experiment, and (2) that internal benchmarking using a conservative test substance in the chemical mixture can be used to correct for growth dilution. Bioconcentration experiments were conducted following major elements of the OECD 305 guideline. Fish were simultaneously exposed to 11 chemicals selected to cover a range of BCFs and susceptibility to biotransformation. A method was developed to calculate the growth-corrected elimination rate constant from the concentration ratio of the analyte and a benchmarking chemical for which growth dilution dominated other elimination mechanisms. This method was applied to the experimental data using hexachlorobenzene as the benchmarking chemical. The growth dilution correction lowered the apparent elimination rate constants by between 5% and a factor of four for eight chemicals, while for two chemicals the growth-corrected elimination rate constant was not significantly different from zero. The benchmarking method reduced the uncertainty in the elimination rate constant compared to the existing method for growth dilution correction. The BCFs from exposing fish to 10 chemicals at once were consistent with BCF values from single-chemical exposures from the literature, supporting hypothesis 1. Environ. Toxicol. Chem. 2012; 31: 18531860. (c) 2012 SETAC

  • 18.
    Aeppli, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Bastviken, David
    Andersson, Per
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Chlorine Isotope Effects and Composition of Naturally Produced Organochlorines from Chloroperoxidases, Flavin-Dependent Halogenases, and in Forest Soil2013Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 13, s. 6864-6871Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The use of stable chlorine isotopic signatures (delta Cl-37) of organochlorine compounds has been suggested as a tool to determine both their origins and transformations in the environment. Here we investigated the delta Cl-37 fractionation of two important pathways for enzymatic natural halogenation: chlorination by chloroperoxidase (CPO) and flavin-dependent halogenases (FDH). Phenolic products of CPO were highly Cl-37 depleted (delta Cl-37 = -12.6 +/- 0.9 parts per thousand); significantly more depleted than all known industrially produced organochlorine compounds (delta Cl-37 = -7 to +6 parts per thousand). In contrast, four FDH products did not exhibit any observable isotopic shifts (delta Cl-37 = -0.3 +/- 0.6 parts per thousand). We attributed the different isotopic effect to the distinctly different chlorination mechanisms employed by the two enzymes. Furthermore, the delta Cl-37 in bulk organochlorines extracted from boreal forest soils were only slightly depleted in Cl-37 relative to inorganic Cl. In contrast to previous suggestions that CPO plays a key role in production of soil organochlorines, this observation points to the additional involvement of either other chlorination pathways, or that dechlorination of naturally produced organochlorines can neutralize delta Cl-37 shifts caused by CPO chlorination. Overall, this study demonstrates that chlorine isotopic signatures are highly useful to understand sources and cycling of organochlorines in nature. Furthermore, this study presents delta Cl-37 values of FDH products as well of bulk organochlorines extracted from pristine forest soil for the first time.

  • 19.
    Aeppli, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Andersson, Per
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Direct compound-specific stable chlorine isotope analysis of organic compounds with quadrupole GC/MS using standard isotope bracketing2010Inngår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 82, nr 1, s. 420-426Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A method has been developed for the direct determination of the stable chlorine isotope composition (delta(37)Cl) of organochlorines that eliminates sample preparation, achieves precision comparable to earlier techniques while improving the sensitivity, and makes use of benchtop gas chromatography-quadrupole mass spectrometry instruments (GCqMS). The method is based on the use of multiple injections (n = 8-10) of the sample, bracketed by a molecularly identical isotopic standard with known delta(37)Cl, determined using off-line thermal ionization mass spectrometry (TIMS). Mass traces of two isotopologues differing by one chlorine isotope were used to calculate delta(37)Cl values. Optimization of mass spectrometry and peak integration parameters as well as method validation was achieved using tetrachloroethene (PCE), p,p'-dichlorodiphenyltrichloroethane (DDT), and pentachlorophenol (PCP), spanning a delta(37)Cl range of -5.5 to +3.2 per thousand vs SMOC. Injecting 1.6-1100 pmol resulted in standard deviations (1sigma) of 0.6-1.3 per thousand, and the delta(37)Cl results agreed with values independently measured with TIMS. The method was tested by determining the Rayleigh fractionation during evaporation of pure liquid PCE, resulting in a chlorine isotopic enrichment factor of epsilon(Cl) = -1.1 +/- 0.4 per thousand. Furthermore, position-specific delta(37)Cl analysis based on analysis of DDT mass fragments was evaluated. The GCqMS-delta(37)Cl method offers a simplified yet sensitive approach for compound-specific chlorine isotope analysis.

  • 20.
    Aeppli, Christoph
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Tysklind, Mats
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Use of Cl and C Isotopic Fractionation to Identify Degradation and Sources of Polychlorinated Phenols: Mechanistic Study and Field Application2013Inngår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 47, nr 2, s. 790-797Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The widespread use of chlorinated phenols (CPs) as a wood preservative has led to numerous contaminated sawmill sites. However, it remains challenging to assess the extent of in situ degradation of CPs. We evaluated the use of compound-specific chlorine and carbon isotope analysis (Cl- and C-CSLA) to assess CP biotransformation. In a laboratory system, we measured isotopic fractionation during oxidative 2,4,6-trichlorophenol dechlorination by representative soil enzymes (C. fumago chloroperoxidase, horseradish peroxidase, and laccase from T. versicolor). Using a mathematical model, the validity of the Rayleigh approach to evaluate apparent kinetic isotope effects (AKIE) was confirmed. A small but significant Cl-AKIE of 1.0022 +/- 0.0006 was observed for all three enzymes, consistent with a reaction pathway via a cationic radical species. For carbon, a slight inverse isotope effect was observed (C-AKIE = 0.9945 +/- 0.0019). This fractionation behavior is clearly distinguishable from reported reductive dechlorination mechanisms. Based on these results we then assessed degradation and apportioned different types of technical CP mixtures used at two former sawmill sites. To our knowledge, this is the first study that makes use of two-element CSIA to study sources and transformation of CPs in the environment.

  • 21.
    Ahlm, L
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nilsson, D
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krejci, R
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mårtensson, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Vogt, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Artaxo, P.
    Aerosol Fluxes over Amazon Rain Forest Measured with the Eddy Covariance Method2008Inngår i: American Geophysical Union (AGU) Fall Meeting 2008: 15-19 December, San Fransisco, CA, USA, 2008Konferansepaper (Fagfellevurdert)
  • 22.
    Ahlm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Aerosol Exchange between Forests and the Atmosphere: Fluxes over a Tropical and a Boreal Forest2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The main goal of this thesis was to investigate primary biogenic aerosol emission from the Amazon rain forest through measurements of vertical turbulent aerosol number fluxes. In addition, the particle dry deposition sink has been analysed and quantified, and is also compared with the dry deposition sink at a boreal forest site.

    The total aerosol number flux of particles with diameter larger than 10 nm was dominated by downward fluxes at the rain forest site, even in the most pristine conditions in the wet season. This is an indication that the primary biogenic aerosol number source is small when considering the total particle size spectrum. However, size resolved aerosol number fluxes indicated net emission for particles with dry diameter 0.5-2.5 μm in clean conditions. These emission fluxes are likely explained by a primary biogenic aerosol source from the rain forest and seemed to be best correlated with horizontal wind speed, peaking during afternoon. Even though there are few particles in this diameter interval, typically one particle per cm3, they could potentially play an important role as giant nuclei in warm rain initiation.

    Average particle number based dry deposition velocities over the whole aerosol population were lower at the rain forest site than at the boreal forest site. The reasons are likely the high fraction of accumulation mode particles at the rain forest site and low wind speeds in the tropics compared to the midlatitudes.

    This thesis provides a relation describing emission of particles with diameter 0.5-2.5 μm from the rain forest, as a function of wind speed. In addition, linear equations relating average dry deposition velocity of the total aerosol number population to friction velocity are suggested for both the wet and dry season at the rain forest site. Finally, this thesis provides a relationship between dry deposition velocity of particles within the diameter range 0.25-0.45 μm, friction velocity and particle diameter.

  • 23.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Julin, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Fountoukis, C.
    Pandis, S. N.
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Particle number concentrations over Europe in 2030: the role of emissions and new particle formation2013Inngår i: Atmospheric Chemistry and Physics Discussions, ISSN 1680-7367, E-ISSN 1680-7375, Vol. 13, nr 20, s. 10271-10283Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The aerosol particle number concentration is a key parameter when estimating impacts of aerosol particles on climate and human health. We use a three-dimensional chemical transport model with detailed microphysics, PMCAMx-UF, to simulate particle number concentrations over Europe in the year 2030, by applying emission scenarios for trace gases and primary aerosols. The scenarios are based on expected changes in anthropogenic emissions of sulfur dioxide, ammonia, nitrogen oxides, and primary aerosol particles with a diameter less than 2.5 mu m (PM2.5) focusing on a photochemically active period, and the implications for other seasons are discussed. For the baseline scenario, which represents a best estimate of the evolution of anthropogenic emissions in Europe, PMCAMx-UF predicts that the total particle number concentration (N-tot) will decrease by 30-70% between 2008 and 2030. The number concentration of particles larger than 100 nm (N-100), a proxy for cloud condensation nuclei (CCN) concentration, is predicted to decrease by 40-70% during the same period. The predicted decrease in N-tot is mainly a result of reduced new particle formation due to the expected reduction in SO2 emissions, whereas the predicted decrease in N-100 is a result of both decreasing condensational growth and reduced primary aerosol emissions. For larger emission reductions, PMCAMx-UF predicts reductions of 60-80% in both N-tot and N-100 over Europe. Sensitivity tests reveal that a reduction in SO2 emissions is far more efficient than any other emission reduction investigated, in reducing N-tot. For N-100, emission reductions of both SO2 and PM2.5 contribute significantly to the reduced concentration, even though SO2 plays the dominant role once more. The impact of SO2 for both new particle formation and growth over Europe may be expected to be somewhat higher during the simulated period with high photochemical activity than during times of the year with less incoming solar radiation. The predicted reductions in both N-tot and N-100 between 2008 and 2030 in this study will likely reduce both the aerosol direct and indirect effects, and limit the damaging effects of aerosol particles on human health in Europe

  • 24.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mårtensson, Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Vogt, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Artaxo, Paulo
    Emission and dry deposition of accumulation mode particles in the Amazon Basin2010Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 10, nr 21, s. 10237-10253Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Size-resolved vertical aerosol number fluxes of particles in the diameter range 0.25–2.5 μm were measured with the eddy covariance method from a 53 m high tower over the Amazon rain forest, 60 km NNW of Manaus, Brazil. This study focuses on data measured during the relatively clean wet season, but a shorter measurement period from the more polluted dry season is used as a comparison. Size-resolved net particle fluxes of the five lowest size bins, representing 0.25–0.45 μm in diameter, pointed downward in more or less all wind sectors in the wet season. This is an indication that the source of primary biogenic aerosol particles may be small in this particle size range. In the diameter range 0.5–2.5 μm, vertical particle fluxes were highly dependent on wind direction. In wind sectors where anthropogenic influence was low, net emission fluxes dominated. However, in wind sectors associated with higher anthropogenic influence, net deposition fluxes dominated. The net emission fluxes were interpreted as primary biogenic aerosol emission, but deposition of anthropogenic particles seems to have masked this emission in wind sectors with higher anthropogenic influence. The emission fluxes were at maximum in the afternoon when the mixed layer is well developed, and these emissions were best correlated with horizontal wind speed by the equation log10F=0.47·U+2.26 where F is the emission number flux of 0.5–2.5 μm particles [m−2s−1] and U is the horizontal wind speed [ms−1] at the top of the tower.

  • 25.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mårtensson, Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Vogt, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Artaxo, Paulo
    Size-resolved dry deposition velocities of particles with diameters 0.25-0.45 μm to a tropical rain forestManuskript (preprint) (Annet vitenskapelig)
  • 26.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Launiainen, S.
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Grönholm, T.
    Rinne, J.
    Mårtensson, Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Aalto, P.
    van Ekeren, S.
    Kulmula, M.
    Vesala, T.
    The boreal forest canopy and aerosol eddy covariance fluxes2007Inngår i: EAC 2007 Salzburg: 9-14/9, 2007Konferansepaper (Annet (populærvitenskap, debatt, mm))
  • 27.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mårtensson, Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Vogt, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Artaxo, Paulo
    A comparison of dry and wet season aerosol number fluxes over the Amazon rain forest2010Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 10, nr 6, s. 3063-3079Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Vertical number fluxes of aerosol particles and vertical fluxes of CO2 were measured with the eddy covariance method at the top of a 53m high tower in the Amazon rain forest as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) experiment. The observed aerosol number fluxes included particles with sizes down to 10 nm in diameter. The measurements were carried out during the wet and dry season in 2008. In this study focus is on the dry season aerosol fluxes, with significant influence from biomass burning, and these are compared with aerosol fluxes measured during the wet season. Net particle deposition fluxes dominated in daytime in both seasons and the deposition flux was considerably larger in the dry season due to the much higher dry season particle concentration. The particle transfer velocity increased linearly with increasing friction velocity in both seasons. The difference in transfer velocity between the two seasons was small, indicating that the seasonal change in aerosol number size distribution is not enough for causing any significant change in deposition velocity. In general, particle transfer velocities in this study are low compared to studies over boreal forests. The reasons are probably the high percentage of accumulation mode particles and the low percentage of nucleation mode particles in the Amazon boundary layer, both in the dry and wet season, and low wind speeds in the tropics compared to the midlatitudes. In the dry season, nocturnal particle fluxes behaved very similar to the nocturnal CO2 fluxes. Throughout the night, the measured particle flux at the top of the tower was close to zero, but early in the morning there was an upward particle flux peak that is not likely a result of entrainment or local pollution. It is possible that these morning upward particle fluxes are associated with emission of primary biogenic particles from the rain forest. Emitted particles may be stored within the canopy during stable conditions at nighttime, similarly to CO2, and being released from the canopy when conditions become more turbulent in the morning.

  • 28.
    Ahlm, Lars
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mårtensson, Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Vogt, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Artaxo, Paulo
    Aerosol number fluxes over the Amazon rain forest during the wet season2009Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 9, nr 24, s. 9381-9400Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Number fluxes of particles with diameter larger than 10 nm were measured with the eddy covariance method over the Amazon rain forest during the wet season as part of the LBA (The Large Scale Biosphere Atmosphere Experiment in Amazonia) campaign 2008. The primary goal was to investigate whether sources or sinks dominate the aerosol number flux in the tropical rain forest-atmosphere system. During the measurement campaign, from 12 March to 18 May, 60% of the particle fluxes pointed downward, which is a similar fraction to what has been observed over boreal forests. The net deposition flux prevailed even in the absolute cleanest atmospheric conditions during the campaign and therefore cannot be explained only by deposition of anthropogenic particles. The particle transfer velocity vt increased with increasing friction velocity and the relation is described by the equation vt=2.4×10−3×u* where u* is the friction velocity. Upward particle fluxes often appeared in the morning hours and seem to a large extent to be an effect of entrainment fluxes into a growing mixed layer rather than primary aerosol emission. In general, the number source of primary aerosol particles within the footprint area of the measurements was small, possibly because the measured particle number fluxes reflect mostly particles less than approximately 200 nm. This is an indication that the contribution of primary biogenic aerosol particles to the aerosol population in the Amazon boundary layer may be low in terms of number concentrations. However, the possibility of horizontal variations in primary aerosol emission over the Amazon rain forest cannot be ruled out.

  • 29. Ahlvik, P
    et al.
    Karlsson, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Westerholm, Roger
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Åsman, P
    Exhaust emissions from flexi-fuel light-duty passenger cars fuelled by petrol (E5) and bioethanol (E70, E85) tested at ambient temperatures of +22°C and -7°C: Part 1:Regulated and particulate emissions.2008Inngår i: Proceedings of the17:th International Symposium on Alcohol Fuels, 2008Konferansepaper (Annet vitenskapelig)
  • 30. Ahrens, L.
    et al.
    Plassmann, Merle
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Xie, Z.Y.
    Ebinghaus, R.
    Determination of polyfluoroalkyl compounds in water and suspended particulate matter in the river Elbe and North Sea, Germany2009Inngår i: Frontiers of Environmental Science & Engineering in China, ISSN 1673-7520, Vol. 3, nr 2, s. 152-170Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The distribution of polyfluoroalkyl compounds (PFCs) in the dissolved and particulate phase and their discharge from the river Elbe into the North Sea were studied. The PFCs quantified included C-4-C-8 perfluorinated sulfonates (PFSAs), 6:2 fluorotelomer sulfonate (6:2 FTS), C-6 and C-8 perfluorinated sulfonates (PFSiAs), C-4-C-12 perfluorinated carboxylic acids (PFCAs), perfluoro-3,7-dimethyl-octanoic acid (3,7m(2)-PFOA), perfluorooctane sulfonamide (FOSA), and n-ethyl perfluroctane sulfonamidoethanol (EtFOSE). PFCs were mostly distributed in the dissolved phase, where perfluorooctanoic acid (PFOA) dominated with 2.9-12.5 ng/L. In the suspended particulate matter FOSA and perfluorooctane sulfonate (PFOS) showed the highest concentrations (4.0 ng/L and 2.3 ng/L, respectively). The total flux of Sigma PFCs from the river Elbe was estimated to be 802 kg/year for the dissolved phase and 152 kg/year for the particulate phase. This indicates that the river Elbe acts as a source of PFCs into the North Sea. However, the concentrations of perfluorobutane sulfonate (PFBS) and perfluorobutanoic acid (PFBA) in the North Sea were higher than that in the river Elbe, thus an alternative source must exist for these compounds

  • 31. Aidas, Kestutis
    et al.
    Agren, Hans
    Kongsted, Jacob
    Laaksonen, Aatto
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mocci, Francesca
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    A quantum mechanics/molecular dynamics study of electric field gradient fluctuations in the liquid phase. the case of na+ in aqueous solution2013Inngår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 15, nr 5, s. 1621-1631Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The Na-23 quadrupolar coupling constant of the Na+ ion in aqueous solution has been predicted using molecular dynamics simulations and hybrid quantum mechanics/molecular mechanics methods for the calculation of electric field gradients. The developed computational approach is generally expected to provide reliable estimates of the quadrupolar coupling constants of monoatomic species in condensed phases, and we show here that intermolecular polarization and non-electrostatic interactions are of crucial importance as they result in a 100% increased quadrupolar coupling constant of the ion as compared to a simpler pure electrostatic picture. These findings question the reliability of the commonly applied classical Sternheimer approximation for the calculations of the electric field gradient. As it can be expected from symmetry considerations, the quadrupolar coupling constants of the 5- and 6-coordinated Na+ ions in solution are found to differ significantly.

  • 32. Allen, G.
    et al.
    Coe, H.
    Clarke, A.
    Bretherton, C.
    Wood, R.
    Abel, S. J.
    Barrett, P.
    Brown, P.
    George, R.
    Freitag, S.
    McNaughton, C.
    Howell, S.
    Shank, L.
    Kapustin, V.
    Brekhovskikh, V.
    Kleinman, L.
    Lee, Y-N
    Springston, S.
    Toniazzo, T.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Fochesatto, J.
    Shaw, G.
    Krecl, P.
    Brooks, B.
    McMeeking, G.
    Bower, K. N.
    Williams, P. I.
    Crosier, J.
    Crawford, I.
    Connolly, P.
    Allan, J. D.
    Covert, D.
    Bandy, A. R.
    Russell, L. M.
    Trembath, J.
    Bart, M.
    McQuaid, J. B.
    Wang, J.
    Chand, D.
    South East Pacific atmospheric composition and variability sampled = ong 20 degrees S during VOCALS-REx2011Inngår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 11, nr 11, s. 5237-5262Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The VAMOS Ocean-Cloud-Atmosphere-Land Regional Experiment (VOCALS-REx) was conducted from 15 October to 15 November 2008 in the South East Pacific (SEP) region to investigate interactions between land, sea and atmosphere in this unique tropical eastern ocean environment and to improve the skill of global and regional models in = presenting the region. This study synthesises selected aircraft, ship = d surface site observations from VOCALS-REx to statistically summarise = d characterise the atmospheric composition and variability of the = rine Boundary Layer (MBL) and Free Troposphere (FT) along the 20 = grees S parallel between 70 degrees W and 85 degrees W. Significant = nal gradients in mean MBL sub-micron aerosol particle size and = mposition, carbon monoxide, sulphur dioxide and ozone were seen over = e campaign, with a generally more variable and polluted coastal = vironment and a less variable, more pristine remote maritime regime. = adients in aerosol and trace gas concentrations were observed to be = sociated with strong gradients in cloud droplet number. The FT was = ten more polluted in terms of trace gases than the MBL in the mean; = wever increased variability in the FT composition suggests an episodic = ture to elevated concentrations. This is consistent with a complex = rtical interleaving of airmasses with diverse sources and hence = llutant concentrations as seen by generalised back trajectory = alysis, which suggests contributions from both local and long-range = urces. Furthermore, back trajectory analysis demonstrates that the = served zonal gradients both in the boundary layer and the free = oposphere are characteristic of marked changes in airmass history with = stance offshore - coastal boundary layer airmasses having been in = cent contact with the local land surface and remote maritime airmasses = ving resided over ocean for in excess of ten days. Boundary layer = mposition to the east of 75 degrees W was observed to be dominated by = astal emissions from sources to the west of the Andes, with evidence = r diurnal pumping of the Andean boundary layer above the height of the = rine capping inversion. Analysis of intra-campaign variability in = mospheric composition was not found to be significantly correlated = th observed low-frequency variability in the large scale flow pattern; = mpaign-average interquartile ranges of CO, SO(2) and O(3) = ncentrations at all longitudes were observed to dominate over much = aller differences in median concentrations calculated between periods = different flow regimes. The campaign climatology presented here aims = provide a valuable dataset to inform model simulation and future = ocess studies, particularly in the context of aerosol-cloud = teraction and further evaluation of dynamical processes in the SEP = gion for conditions analogous to those during VOCALS-REx. To this end, = r results are discussed in terms of coastal, transitional and remote = atial regimes in the MBL and FT and a gridded dataset are provided as = resource.

  • 33.
    Alling, Vanja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Terrestrial organic carbon dynamics in Arctic coastal areas: budgets and multiple stable isotope approaches2010Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Arctic rivers transport 31-42 Tg organic carbon (OC) each year to the Arctic Ocean, which is equal to 10% of the global riverine OC discharge. Since the Arctic Ocean only holds approximately 1% of the global ocean volume, the influence of terrestrially derived organic carbon (OCter) in the Arctic Ocean is relatively high. Despite the global importance of this region the behavior of the, by far largest fraction of the OCter, the dissolved organic carbon (DOC) in Arctic and sub-arctic estuaries is still a matter of debate. This thesis describes data originating from field cruises in Arctic and sub-arctic estuaries and coastal areas with the aim to improve the understanding of the fate of OCter in these areas, with specific focus on DOC. All presented studies indicate that DOCter and terrestrially derived particulate organic carbon (POCter) are subjected to substantial degradation in high-latitude estuaries, as shown by the non-conservative behavior of DOC in the East Siberian Arctic Shelf Seas (ESAS) (paper I) and the even more rapid degradation of POC in the same region (paper II). The removals of OCter in Arctic shelf seas were further supported by multiple isotope studies (paper III and IV), which showed that a use of 13C/12C in both OC and DIC, together with 34S/32S is a powerful tool to describe the sources and fate of OCter in estuaries and coastal seas. High-latitude estuaries play a key role in the coupling between terrestrial and marine carbon pools. In contrast to the general perception, this thesis shows that they are not only transportation areas for DOCter from rivers to the ocean, but are also active sites for transformation, degradation and sedimentation of DOCter, as well as for POCter. In a rapidly changing climate, the importance of these areas for the coupling between inorganic and organic carbon pools cannot be underestimated.

  • 34. Alling, Vanja
    et al.
    Hale, Sarah E.
    Martinsen, Vegard
    Mulder, Jan
    Smebye, Andreas
    Breedveld, Gijs D.
    Cornelissen, Gerard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM). Norwegian University of Life Sciences, Norway; Norwegian Geotechnical Institute (NGI), Norway.
    The role of biochar in retaining nutrients in amended tropical soils2014Inngår i: Journal of Plant Nutrition And Soil Science/Zeitschrift für Pflanzenernahrung und Bodenkunde, ISSN 1436-8730, E-ISSN 1522-2624, Vol. 177, nr 5, s. 671-680Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This study investigated the effect of biochar amendments on the retention and availability of plant nutrients and Al in seven acidic tropical soils from Zambia and Indonesia. The experiments carried out investigated whether the adsorption capacity of NH4+ in the soils increased upon the addition of biochar and which effect biochar had on available concentrations of NO3-, K+, Mn2+, Mg2+, PO43-, and Al3+. These nutrients were selected as they represent those important to plant growth and soil quality. No significant increases or decreases in aqueous NH4+-N concentration with additions of biochar were detected. The Gaines-Thomas model was used in order to calculate selectivity coefficients for NH4+ exchange (K-gt values). Following the addition of biochar to soil, K-gt values decreased showing a reduction in the selective binding of NH4+ in the biochar amended soil compared to the control. The concentration of NO3- increased following the addition of biochar to the soils. The addition of 5 and 10% biochar to the Indonesian soil did not significantly alter (t-test confidence level 0.05) the sorption of PO43- to the soil-biochar mixtures as compared to the soil alone. However, the addition of biochar to the soil from Zambia increased the sorption of PO43- compared to the soil alone. The concentrations of K+ and Mg2+ were significantly increased for almost all soils (t-test at the 0.05 confidence level) following the addition of biochar. Addition of biochar to all but two soils significantly decreased (t-test confidence level 0.05) Mn2+ concentrations. The concentration of Al3+ in the soils decreased exponentially significantly (t-test confidence level 0.05) following the amendment of biochar in accordance with the increase in pH observed when biochar was added to the soil. These results show that biochar has the ability to release essential plant growth nutrients as well as alleviate Al toxicity in these soils.

  • 35.
    Alling, Vanja
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Rahm, Lars
    Polehne, Falk
    Tracing terrestrial organic matter by delta34S and delta13C signatures in a subarctic estuary2008Inngår i: Limnology and Oceanography, ISSN 0024-3590, E-ISSN 1939-5590, Vol. 53, nr 6, s. 2594-2602Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A key issue to understanding the transformations of terrestrial organic carbon in the ocean is to disentangle the latter from marine-produced organic matter. We applied a multiple stable isotope approach using 34S and 13C isotope signatures from estuarine dissolved organic matter (DOM), enabling us to constrain the contribution of terrestrial-derived DOM in an estuarine gradient of the northern Baltic Sea. The stable isotope signatures for dissolved organic sulfur (34SDOS) have twice the range between terrestrial and marine end members compared to the stable isotope signatures for dissolved organic carbon (13CDOC); hence, the share of terrestrial DOM in the total estuarine DOM can be calculated more precisely. DOM samples from the water column were collected using ultrafiltration on board the German RV Maria S Merian during a winter cruise, in the Bothnian Bay, Bothnian Sea, and Baltic proper. We calculated the terrestrial fraction of the estuarine DOC (DOCter) from both 13CDOC and 34SDOS signatures and applying fixed C: S ratios for riverine and marine end members to convert S isotope signatures into DOC concentrations. The 34SDOS signature of the riverine end member was +7.02‰, and the mean signatures from Bothnian Bay, Bothnian Sea, and Baltic proper were +10.27, +12.51, and +13.67‰, respectively, showing an increasing marine signal southwards (34SDOS marine end member 5 18.1‰). These signatures indicate that 87‰, 75‰, and 67‰, respectively, of the water column DOC is of terrestrial origin (DOCter) in these basins. Comparing the fractions of DOCter in each basin—that are still based on few winter values only—with the annual river input of DOC, it appears that the turnover time for DOCter in the Gulf of Bothnia is much shorter than the hydraulic turnover time, suggesting that high-latitude estuaries might be efficient sinks for DOCter.

  • 36.
    Alling, Vanja
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Porcelli, D.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Stockholms universitet, Stockholm Resilience Centre, Baltic Nest Institute.
    Anderson, L. G.
    Sanchez-Garcia, L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Andersson, P. S.
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM). Stockholms universitet, Stockholm Resilience Centre, Baltic Nest Institute.
    Degradation of terrestrial organic carbon, primary production and out-gassing of CO2 in the Laptev and East Siberian Seas as inferred from delta C-13 values of DIC2012Inngår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 95, s. 143-159Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cycling of carbon on the Arctic shelves, including outgassing of CO2 to the atmosphere, is not clearly understood. Degradation of terrestrial organic carbon (OCter) has recently been shown to be pronounced over the East Siberian Arctic Shelf (ESAS), i.e. the Laptev and East Siberian Seas, producing dissolved inorganic carbon (DIC). To further explore the processes affecting DIC, an extensive suite of shelf water samples were collected during the summer of 2008, and assessed for the stable carbon isotopic composition of DIC (delta C-13(DIC)). The delta C-13(DIC) values varied between -7.2 parts per thousand to +1.6 parts per thousand and strongly deviated from the compositions expected from only mixing between river water and seawater. Model calculations suggest that the major processes causing these deviations from conservative mixing were addition of (DIC) by degradation of OCter, removal of DIC during primary production, and outgassing of CO2. All waters below the halocline in the ESAS had delta C-13(DIC) values that appear to reflect mixing of river water and seawater combined with additions of on average 70 +/- 20 mu M of DIC, originating from degradation of OCter in the coastal water column. This is of the same magnitude as the recently reported deficits of DOCter and POCter for the same waters. The surface waters in the East Siberian Sea had higher delta C-13(DIC) values and lower DIC concentrations than expected from conservative mixing, consistent with additions of DIC from degradation of OCter and outgassing of CO2. The outgassing of CO2 was equal to loss of 123 +/- 50 mu M DIC. Depleted delta C-13(POC) values of -29 parts per thousand to -32 parts per thousand in the mid to outer shelf regions are consistent with POC from phytoplankton production. The low delta C-13(POC) values are likely due to low delta C-13(DIC) of precursor DIC, which is due to degradation of OCter, rather than reflecting terrestrial input compositions. Overall, the delta C-13(DIC) values confirm recent suggestions of substantial degradation of OCter over the ESAS, and further show that a large part of the CO2 produced from degradation has been outgassed to the atmosphere.

  • 37.
    Alling, Vanja
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sanchez-Garcia, Laura
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Porcelli, Don
    Pugach, Sveta
    Vonk, Jorien E.
    van Dongen, Bart
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Stockholms universitet, Stockholm Resilience Centre.
    Anderson, Leif G.
    Sokolov, Alexander
    Stockholms universitet, Stockholm Resilience Centre.
    Andersson, Per
    Humborg, Christoph
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM). Stockholms universitet, Stockholm Resilience Centre.
    Semiletov, Igor
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Non-conservative behavior of dissolved organic carbon across the Laptev and East Siberian Seas2010Inngår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 24, s. GB4033-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Climate change is expected to have a strong effect on the Eastern Siberian Arctic Shelf (ESAS) region, which includes 40% of the Arctic shelves and comprises the Laptev and East Siberian seas. The largest organic carbon pool, the dissolved organic carbon (DOC), may change significantly due to changes in both riverine inputs and transformation rates; however, the present DOC inventories and transformation patterns are poorly understood. Using samples from the International Siberian Shelf Study 2008, this study examines for the first time DOC removal in Arctic shelf waters with residence times that range from months to years. Removals of up to 10%–20% were found in the Lena River estuary, consistent with earlier studies in this area, where surface waters were shown to have a residence time of approximately 2 months. In contrast, the DOC concentrations showed a strong nonconservative pattern in areas with freshwater residence times of several years. The average losses of DOC were estimated to be 30%–50% during mixing along the shelf, corresponding to a first-order removal rate constant of 0.3 yr−1. These data provide the first observational evidence for losses of DOC in the Arctic shelf seas, and the calculated DOC deficit reflects DOC losses that are higher than recent model estimates for the region. Overall, a large proportion of riverine DOC is removed from the surface waters across the Arctic shelves. Such significant losses must be included in models of the carbon cycle for the Arctic Ocean, especially since the breakdown of terrestrial DOC to CO2 in Arctic shelf seas may constitute a positive feedback mechanism for Arctic climate warming. These data also provide a baseline for considering the effects of future changes in carbon fluxes, as the vast northern carbon-rich permafrost areas draining into the Arctic are affected by global warming.

  • 38.
    Allmyr, M
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Harden, F.
    Toms, L-ML.
    Mueller, J.F.
    McLachlan, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Adolfsson-Erici, M
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sandborgh Englund, G.
    The influence of age and gender on triclosan concentrations in Australian human blood serum2008Inngår i: Sci. Tot. Environ.Artikkel i tidsskrift (Fagfellevurdert)
  • 39.
    Allmyr, Mats
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Panagiotidis, Georgios
    Sparve, Erik
    Diczfalusy, Ulf
    Sandborgh-Englund, Gunilla
    Human Exposure to Triclosan via Toothpaste does not change CYP3A4 Activity or Plasma Concentrations of Thyroid Hormones2009Inngår i: Basic & Clinical Pharmacology & Toxicology, ISSN 1742-7835, E-ISSN 1742-7843, Vol. 105, nr 5, s. 339-344Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Triclosan is an antibacterial compound commonly used in cosmetics and personal care products for everyday use. As previously shown, triclosan is found in the plasma, urine and milk from large parts of different human populations. Recent studies have revealed that triclosan is able to activate the human pregnane X receptor in vitro and thus possibly affecting metabolism of drugs in humans via the induction of CYP3A4. Besides, triclosan has been shown to affect thyroid hormonal levels in rats in vivo. In the present study, we investigated if an everyday exposure to triclosan via triclosan-containing toothpaste for 14 days in 12 adult humans caused an increase in plasma 4 beta-hydroxycholesterol, indicative of CYP3A4 induction, and/or alterations in thyroid hormonal status. The plasma triclosan concentrations increased from 0.009-0.81 ng/g to 26-296 ng/g (ranges) upon exposure. Despite this, there were no significant changes in plasma levels of either plasma 4 beta-hydroxycholesterol or thyroid hormones during the exposure. This indicates that the normal use of triclosan-containing toothpaste is not likely to alter metabolism of drugs via CYP3A4 induction or cause adverse events because of thyroid disturbances in humans.

  • 40. Almeida, Joao
    et al.
    Schobesberger, Siegfried
    Kuerten, Andreas
    Ortega, Ismael K.
    Kupiainen-Maatta, Oona
    Praplan, Arnaud P.
    Adamov, Alexey
    Amorim, Antonio
    Bianchi, Federico
    Breitenlechner, Martin
    David, Andre
    Dommen, Josef
    Donahue, Neil M.
    Downard, Andrew
    Dunne, Eimear
    Duplissy, Jonathan
    Ehrhart, Sebastian
    Flagan, Richard C.
    Franchin, Alessandro
    Guida, Roberto
    Hakala, Jani
    Hansel, Armin
    Heinritzi, Martin
    Henschel, Henning
    Jokinen, Tuija
    Junninen, Heikki
    Kajos, Maija
    Kangasluoma, Juha
    Keskinen, Helmi
    Kupc, Agnieszka
    Kurten, Theo
    Kvashin, Alexander N.
    Laaksonen, Ari
    Lehtipalo, Katrianne
    Leiminger, Markus
    Leppa, Johannes
    Loukonen, Ville
    Makhmutov, Vladimir
    Mathot, Serge
    McGrath, Matthew J.
    Nieminen, Tuomo
    Olenius, Tinja
    Onnela, Antti
    Petaja, Tuukka
    Riccobono, Francesco
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Rissanen, Matti
    Rondo, Linda
    Ruuskanen, Taina
    Santos, Filipe D.
    Sarnela, Nina
    Schallhart, Simon
    Schnitzhofer, Ralf
    Seinfeld, John H.
    Simon, Mario
    Sipila, Mikko
    Stozhkov, Yuri
    Stratmann, Frank
    Tome, Antonio
    Troestl, Jasmin
    Tsagkogeorgas, Georgios
    Vaattovaara, Petri
    Viisanen, Yrjo
    Virtanen, Annele
    Vrtala, Aron
    Wagner, Paul E.
    Weingartner, Ernest
    Wex, Heike
    Williamson, Christina
    Wimmer, Daniela
    Ye, Penglin
    Yli-Juuti, Taina
    Carslaw, Kenneth S.
    Kulmala, Markku
    Curtius, Joachim
    Baltensperger, Urs
    Worsnop, Douglas R.
    Vehkamaki, Hanna
    Kirkby, Jasper
    Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere2013Inngår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 502, nr 7471, s. 359-+Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nucleation of aerosol particles from trace atmospheric vapours is thought to provide up to half of global cloud condensation nuclei(1). Aerosols can cause a net cooling of climate by scattering sunlight and by leading to smaller but more numerous cloud droplets, which makes clouds brighter and extends their lifetimes(2). Atmospheric aerosols derived from human activities are thought to have compensated for a large fraction of the warming caused by greenhouse gases(2). However, despite its importance for climate, atmospheric nucleation is poorly understood. Recently, it has been shown that sulphuric acid and ammonia cannot explain particle formation rates observed in the lower atmosphere(3). It is thought that amines may enhance nucleation(4-16), but until now there has been no direct evidence for amine ternary nucleation under atmospheric conditions. Here we use the CLOUD (Cosmics Leaving OUtdoor Droplets) chamber at CERN and find that dimethylamine above three parts per trillion by volume can enhance particle formation rates more than 1,000-fold compared with ammonia, sufficient to account for the particle formation rates observed in the atmosphere. Molecular analysis of the clusters reveals that the faster nucleation is explained by a base-stabilization mechanism involving acid-amine pairs, which strongly decrease evaporation. The ion-induced contribution is generally small, reflecting the high stability of sulphuric acid-dimethylamine clusters and indicating that galactic cosmic rays exert only a small influence on their formation, except at low overall formation rates. Our experimental measurements are well reproduced by a dynamical model based on quantum chemical calculations of binding energies of molecular clusters, without any fitted parameters. These results show that, in regions of the atmosphere near amine sources, both amines and sulphur dioxide should be considered when assessing the impact of anthropogenic activities on particle formation.

  • 41.
    Alsberg,
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Kärsrud,
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Broms, S.
    Gleisner, M.
    Provningsjämförelse 2007 - Bestämning av petroleumkolväten i standardlösningar, vatten och jord med GC/MS2007Rapport (Annet (populærvitenskap, debatt, mm))
  • 42.
    Alsberg, T
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Kärsrud, A
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gleisner, M.
    Provningsjämförelse 2008 - Bestämning av petroleumkolväten i standardlösningar, vatten och jord med GC/MS2008Rapport (Annet vitenskapelig)
  • 43.
    Alsberg, T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Minten, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Haglund, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
    Törnqvist, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljökemi.
    Determination of hydroxyalkyl derivatives of cobalamin (vitamin B12) using reversed phase high performance liquid chromatography with electrospray tandem mass spectrometry and ultraviolet diode array detection2001Inngår i: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 15, nr 24, s. 2438-45Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) and ultraviolet diode array detection (UV-DAD), coupled on-line to reversed phase high performance liquid chromatography (HPLC), was used for the characterization of hydroxyalkyl derivatives of cob(I)alamin. The reduced form of vitamin B12, cob(I)alamin, denoted a supernucleophile due to its high nucleophilic strength, has shown promise as an analytical tool in studies of electrophilically reactive compounds in vitro and in vivo. A method for analysis of DNA-phosphate adducts was developed earlier utilizing the supernucleophilicity of cob(I)alamin to transfer alkyl groups from the phosphotriester configuration in DNA, with the formation of a Co-substituted alkyl-cobalamin (alkyl-Cbl) complex. For the purpose of identification and quantification of alkyl-Cbls at high sensitivity, an MS/MS method has been developed with application to a number of 2-hydroxyalkyl-cobalamins (OHalkyl-Cbls). The precursor oxiranes were reacted with cob(I)alamin, followed by clean-up and mass spectrometric analysis of the resulting OHalkyl-Cbls. It was found that ionization was highly dependent on solvent composition. By using acetonitrile/water/trifluoroacetic acid (TFA) (eluent I), the base peak was the doubly protonated molecule [M + 2H](2+), whereas acetonitrile/water/1-methylpiperidine (eluent II) yielded the singly protonated molecule [M + H](+) as the base peak. Excellent separation was obtained with eluent II, with good separation between stereoisomers, thus enabling the characterization of these by means of UV spectra. Limits of quantitation for 2-hydroxypropyl-cobalamin (OHPr-Cbl) were 0.2 and 2 pg/microL (or 0.1 and 1 fmol/microL) using selected ion recording (SIR) with eluent I and II, respectively. The obtained detection level should be sufficient for analysis of alkyl-Cbls from a wide range of toxicological applications.

  • 44. Amato, F.
    et al.
    Querol, X.
    Johansson, C.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Nagl, C.
    Alastuey, A.
    A review on the effectiveness of street sweeping, washing and dust suppressants as urban PM control methods2010Inngår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 408, nr 16, s. 3070-3084Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Given the absence of a definitive threshold for atmospheric particulate matter (PM)-induced adverse health effects and the evidence of road traffic as a main contributor to PM-urban levels, there is a general agreement in reducing PM-associated health risks by firstly focusing on vehicle traffic sector. Beside the reduction of primary exhaust emissions, recent potential measures are challenging to reduce emissions of particulate matter from abrasion and resuspension processes given the high potential health burden of heavy metals and metalloids sourced by vehicle-wear particles (brakes, tires, rotor, discs and catalysts) and of coarse particles (PM2.5-10). Some mitigating measures can be adopted in order to reduce road dust emissions from paved roads by removing or binding those particles already deposited and easy to be resuspended by traffic-generated turbulence. Sweeping, water flushing and use of chemical suppressants are usually more commonly employed to try to diminish emissions, but evaluating the effectiveness of preventive measures on improving air quality is a difficult task, consequently there is a general dearth of information about their effectiveness in reducing ambient PM concentrations. In particular, the scientific bibliography seems to be particularly scarce, whilst most of the information comes from local authorities committees. Consequently the existing reports are often aimed only to the municipalities and in the native language, with an objective difficulty for the international scientific community to access to them. For this review we have gathered contributions from some of major experts in this field, with the purpose of taking advantage of their background and personal awareness about any kind of related reports even not in English. Furthermore, the results we have gathered are often dissimilar, probably due to the different local conditions (weather, road pavement conditions etc.), therefore another objective of the review is to make a balance of actual knowledge and create a useful reference for future research studies and air quality management.

  • 45. Amcoff, Patric
    et al.
    Åkerman, Gun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Börjeson, Hans
    Tjärnlund, Ulla
    Norrgren, Leif
    Balk, Lennart
    Hepatic activities of thiamine-dependent enzymes, glucose-6-phosphate dehydrogenase and cytochrome P4501A in Baltic salmon (Salmo salar) yolk-sac fry after thiamine treatment2000Inngår i: Aquatic Toxicology, ISSN 0166-445X, Vol. 48, nr 4, s. 391-402Artikkel i tidsskrift (Fagfellevurdert)
  • 46. Amstaetter, Katja
    et al.
    Eek, Espen
    Cornelissen, Gerard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sorption of PAHs and PCBs to activated carbon: Coal versus biomass-based quality2012Inngår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 87, nr 5, s. 573-578Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The addition of activated carbon (AC) is an increasingly popular method for pollutant immobilization, and the AC material can be made of biomass or coal/fossil feedstock. The aim of the present study was to investigate whether there are differences between pollutant sorption to biomass and coal-based AC in the presence and absence of sediment. Through N-2 and CO2 adsorption to probe surface area and pore size it was shown that the biomass-based AC had a stronger dominance of narrow pores in the size range 3.5-15 angstrom than the anthracite-based material. In the absence of sediment, sorption isotherms for the probe compounds pyrene and PCB-101 showed stronger sorption for the biomass-based AC (logarithmic Freundlich coefficients 8.15 for pyrene; 9.91 for PCB-101) than for the anthracite-based one (logarithmic Freundlich coefficients 7.20 and 9.70, respectively). In the presence of sediment, the opposite trend was observed, with the stronger sorption for anthracite-based AC. Thus, the presence of competing and/or pore-blocking sediment constituents reduces sorption to a larger extent for biomass-derived AC (factor of 5 for pyrene to almost 100 for PCB-101) than for anthracite-based AC (no reduction for pyrene to factor of 5 for PCB-101). This difference is tentatively attributed to the difference in pore size distribution, narrow pores being more prone to clogging, and could have implications for remediation feasibility with AC from different sources.

  • 47. Anav, Alessandro
    et al.
    Friedlingstein, Pierre
    Beer, Christian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Ciais, Philippe
    Harper, Anna
    Jones, Chris
    Murray-Tortarolo, Guillermo
    Papale, Dario
    Parazoo, Nicholas C.
    Peylin, Philippe
    Piao, Shilong
    Sitch, Stephen
    Viovy, Nicolas
    Wiltshire, Andy
    Zhao, Maosheng
    Spatiotemporal patterns of terrestrial gross primary production: A review2015Inngår i: Reviews of geophysics, ISSN 8755-1209, E-ISSN 1944-9208, Vol. 53, nr 3, s. 785-818Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Great advances have been made in the last decade in quantifying and understanding the spatiotemporal patterns of terrestrial gross primary production (GPP) with ground, atmospheric, and space observations. However, although global GPP estimates exist, each data set relies upon assumptions and none of the available data are based only on measurements. Consequently, there is no consensus on the global total GPP and large uncertainties exist in its benchmarking. The objective of this review is to assess how the different available data sets predict the spatiotemporal patterns of GPP, identify the differences among data sets, and highlight the main advantages/disadvantages of each data set. We compare GPP estimates for the historical period (1990-2009) from two observation-based data sets (Model Tree Ensemble and Moderate Resolution Imaging Spectroradiometer) to coupled carbon-climate models and terrestrial carbon cycle models from the Fifth Climate Model Intercomparison Project and TRENDY projects and to a new hybrid data set (CARBONES). Results show a large range in the mean global GPP estimates. The different data sets broadly agree on GPP seasonal cycle in terms of phasing, while there is still discrepancy on the amplitude. For interannual variability (IAV) and trends, there is a clear separation between the observation-based data that show little IAV and trend, while the process-based models have large GPP variability and significant trends. These results suggest that there is an urgent need to improve observation-based data sets and develop carbon cycle modeling with processes that are currently treated either very simplistically to correctly estimate present GPP and better quantify the future uptake of carbon dioxide by the world's vegetation.

  • 48.
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    A systematic examination of a random sampling strategy for source apportionment calculations2011Inngår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 412, s. 232-238Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Estimating the relative contributions from multiple potential sources of a specific component in a mixed environmental matrix is a general challenge in diverse fields such as atmospheric, environmental and earth sciences. Perhaps the most common strategy for tackling such problems is by setting up a system of linear equations for the fractional influence of different sources. Even though an algebraic solution of this approach is possible for the common situation with N + 1 sources and N source markers, such methodology introduces a bias, since it is implicitly assumed that the calculated fractions and the corresponding uncertainties are independent of the variability of the source distributions. Here, a random sampling (RS) strategy for accounting for such statistical bias is examined by investigating rationally designed synthetic data sets. This random sampling methodology is found to be robust and accurate with respect to reproducibility and predictability. This method is also compared to a numerical integration solution for a two-source situation where source variability also is included. A general observation from this examination is that the variability of the source profiles not only affects the calculated precision but also the mean/median source contributions.

  • 49.
    Andersson, August
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Sheesley, Rebecca J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Krusa, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Johansson, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    (14)C-Based source assessment of soot aerosols in Stockholm and the Swedish EMEP-Aspvreten regional background site2011Inngår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 45, nr 1, s. 215-222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Combustion-derived soot or black carbon (BC) in the atmosphere has a strong influence on both climate and human health. In order to propose effective mitigation strategies for BC emissions it is of importance to investigate geographical distributions and seasonal variations of BC emission sources. Here, a radiocarbon methodology is used to distinguish between fossil fuel and biomass burning sources of soot carbon (SC). SC is isolated for subsequent off-line (14)C quantification with the chemothermal oxidation method at 375 degrees C (CTO-375 method), which reflects a recalcitrant portion of the BC continuum known to minimize inadvertent inclusion of any non-pyrogenic organic matter. Monitored wind directions largely excluded impact from the Stockholm metropolitan region at the EMEP-Aspvreten rural station 70 km to the south-west. Nevertheless, the Stockholm city and the rural stations yielded similar relative source contributions with fraction biomass (f(biomass)) for fall and winter periods in the range of one-third to half. Large temporal variations in (14)C-based source apportionment was noted for both the 6 week fall and the 4 month winter observations. The f(biomass) appeared to be related to the SC concentration suggesting that periods of elevated BC levels may be caused by increased wood fuel combustion. These results for the largest metropolitan area in Scandinavia combine with other recent (14)C-based studies of combustion-derived aerosol fractions to suggest that biofuel combustion is contributing a large portion of the BC load to the northern European atmosphere.

  • 50.
    Andersson, Camilla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för tillämpad miljövetenskap (ITM).
    Air Pollution Dependency on Climate Variability and Source Region: Past, Current and Future Air Pollution Scenarios over Europe2009Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The main objectives of this thesis were to investigate the dependency of European air pollution on climate variability and emission source region. Calculations with a chemistry transport model (CTM) were conducted to investigate the influence of climate variability. The CTM was forced by both simulated past (a re-analysis spanning 1958-2001) and future (a climate simulation spanning 1961-2100) meteorology keeping anthropogenic emissions constant. To investigate the influence of emission source region emissions were varied in western, eastern and northern Europe in seven-year (1997-2003) simulations.

    The main conclusions in this thesis are

    §         There is variability in air pollution due to climate variability on time scales from year to year to decades and long-term trends. Hence, what is measured now will not be valid in a decade, or even next year.

    §         Interannual variability in air pollution due to climate variability is greater than interannual variability in anthropogenic emissions.

    §         The extreme conditions in 2003, resulting in elevated surface O3 concentrations, could be an indication on what we can expect in the future.

    §         The trend in surface O3 over the past due to climate change is similar to the projected trend due to future climate change: increasing in south-western and central Europe and decreasing in north-eastern Europe.

    §         Changes in isoprene emissions and dry deposition dependency on soil moisture are of importance for changes in surface O3 in central and southern Europe. It is vital to include these processes, especially the latter in climate change effect studies of surface O3.

    §         This work indicates that it is of greater importance for health benefits of the European population to reduce primary PM emissions than precursors of secondary inorganic aerosol under the assumption of higher relative risk for primary PM. This is especially the case in western Europe.

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