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  • 301.
    Höpner, Friederike
    et al.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Bender, Frida A. -M.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Ekman, Annica M. L.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Praveen, P. S.
    Bosch, Carme
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Fundació CTM Centre Tecnològic, Spain.
    Ogren, J. A.
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ramanathan, V.
    Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 20122016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 2, p. 1045-1064Article in journal (Refereed)
    Abstract [en]

    A detailed analysis of optical and microphysical properties of aerosol particles during the dry winter monsoon season above the northern Indian Ocean is presented. The Cloud Aerosol Radiative Forcing Experiment (CARDEX), conducted from 16 February to 30 March 2012 at the Maldives Climate Observatory on Hanimaadhoo island (MCOH) in the Republic of the Maldives, used autonomous unmanned aerial vehicles (AUAV) to perform vertical in situ measurements of particle number concentration, particle number size distribution as well as particle absorption coefficients. These measurements were used together with surface-based Mini Micro Pulse Lidar (MiniMPL) observations and aerosol in situ and off-line measurements to investigate the vertical distribution of aerosol particles. Air masses were mainly advected over the Indian subcontinent and the Arabian Peninsula. The mean surface aerosol number concentration was 1717 +/- 604cm(-3) and the highest values were found in air masses from the Bay of Bengal and Indo-Gangetic Plain (2247 +/- 370cm(-3)). Investigations of the free tropospheric air showed that elevated aerosol layers with up to 3 times higher aerosol number concentrations than at the surface occurred mainly during periods with air masses originating from the Bay of Bengal and the Indo-Gangetic Plain. This feature is different compared to what was observed during the Indian Ocean Experiment (INDOEX) conducted in winter 1999, where aerosol number concentrations generally decreased with height. In contrast, lower particle absorption at the surface (sigma(abs)(520nm) = 8.5 + 4.2Wm(-1)) was found during CARDEX compared to INDOEX 1999. Layers with source region specific single-scattering albedo (SSA) values were derived by combining vertical in situ particle absorption coefficients and scattering coefficients calculated with Mie theory. These SSA layers were utilized to calculate vertical particle absorption profiles from MiniMPL profiles. SSA surface values for 550 nm for dry conditions were found to be 0 : 94 +/- 0 : 02 and 0 : 91 +/- 0 : 02 for air masses from the Arabian Sea (and Middle East countries) and India (and Bay of Bengal), respectively. Lidar-derived particle absorption coefficient profiles showed both a similar magnitude and structure as the in situ profiles measured with the AUAV. However, primarily due to insufficient accuracy in the SSA estimates, the lidar-derived absorption coefficient profiles have large uncertainties and are generally weakly correlated to vertically in situ measured particle absorption coefficients. Furthermore, the mass absorption efficiency (MAE) for the northern Indian Ocean during the dry monsoon season was calculated to determine equivalent black carbon (EBC) concentrations from particle absorption coefficient measurements. A mean MAE of 11.6 and 6.9m(2) g(-1) for 520 and 880 nm, respectively, was found, likely representing internally mixed BC containing particles. Lower MAE values for 880 and 520 nm were found for air masses originating from dust regions such as the Arabian Peninsula and western Asia (MAE(880 nm) = 5.6m(2) g(-1), MAE(520 nm) = 9.5m(2) g(-1)) or from closer source regions as southern India (MAE(880 nm) = 4.3m(2) g(-1), MAE(520 nm) = 7. 3m(2) g(-1)).

  • 302.
    Iadaresta, Francesco
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Crescenzi, Carlo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Universita di Salerno, Italy.
    Amini, Ahmad
    Colmsjö, Anders
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Koyi, Hirsh
    Abdel-Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Application of graphitic sorbent for online microextraction of drugs in human plasma samples2015In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1422, p. 34-42Article in journal (Refereed)
    Abstract [en]

    In the present work a new sorbent based on graphitized carbon (CarbonX (R) COA) was evaluated in microextraction by packed sorbent (MEPS) for extraction of lidocaine and ropivacaine from human plasma samples. The new graphitic sorbent showed high recoveries of lidocaine and ropivacaine compared to C18 sorbent In the present study the G-MEPS (syringe packed with graphitic sorbent) was connect online with liquid chromatography tandem mass spectrometry (LC-MS/MS). In order to obtain a fast and reliable method different factors affecting MEPS performance were investigated. The extraction efficiency of the graphitic sorbent was compared with silica-based sorbents used in MEPS. The G-MEPS was also evaluated for reuse (50-100 times). The recoveries of lidocaine and ropivacaine from plasma samples were 79% and 82%; respectively. The method was validated according to FDA (Food and Drug Administration) guideline for bioanalytical method validation. Linearity was assessed in the range 5-2000 nmol/L, with coefficient of determination r(2) > 0,995 (n=3) for lidocaine and r(2) > 0.997 (n=3) for ropivacaine. The lower limit of quantification (LLOQ) was 5 nmol/L and the limit of detection (LOD) was 1 nmol/L for studied analytes in plasma samples. For both analytes considered in this study the accuracy values in plasma samples were ranged from 86% to 113%. The Inter-day precisions, expressed as relative standard deviation (%RSD), at three different concentrations (QC-samples) ranged from 8% to 9% for lidocaine, and from 4% to 11% for ropivacaine.

  • 303.
    Iadaresta, Francesco
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Manniello, Michele Dario
    Östman, Conny
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Crescenzi, Carlo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Salerno, Italy.
    Holmbäck, Jan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Russo, Paola
    Chemicals from textiles to skin: an in vitro permeation study of benzothiazole2018In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, no 25, p. 24629-24638Article in journal (Refereed)
    Abstract [en]

    Despite the possible impact on human health, few studies have been conducted to assess the penetration and accumulation of contaminants in the skin after a prolonged contact with textile materials. In previous studies, we have shown that benzothiazole and its derivatives, as well as other potentially hazardous chemicals, often are present as textile contaminants in clothes available on the retail market. Since benzothiazole is a common contaminant in clothes, these can be a possible route for human chemical exposure, both systemic and onto the skin. To investigate this potential exposure, Franz-type and flow-through cells were used for the permeation studies together with a Strat-MA (R) artificial membranes. Experiments were performed using solutions of benzothiazole, as well as contaminated textile samples in the donor chamber. Benzothiazole was demonstrated to penetrate through, as well as being accumulated in the membrane mimicking the skin. After 24 h, up to 62% of benzothiazole was found in the acceptor cell, while up to 37% was found absorbed in the skin mimicking membrane. It also was shown that there was release and permeation from contaminated fabrics. The results indicate that benzothiazole can be released from textile materials, penetrate through the skin, and further enter the human body. This will possibly also apply to other chemical contaminants in textiles, and the results of this study indicate that the presence of these textile contaminants entails potential health risks. A rough risk assessment was made for clothing textiles according to Environmental Protection Agency (EPA) and European regulations for carcinogenic and non-carcinogenic compounds, using literature data for benzothiazole.

  • 304.
    Ingre-Khans, Ellen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University.
    Transparency within REACH?: Regulatory risk assessment of industrial chemicals2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chemicals provide us with many benefits but can also have adverse effects on human health and the environment. Concerns that previous European legislations were not providing adequate protection from chemical risks resulted in a new chemicals legislation – REACH – in 2007. According to REACH, the chemical industry must ensure that risks from chemicals they produce or import at or above one tonne per year can be adequately controlled. Data on the chemicals’ properties and uses, hazards and risks as well as instructions for safely handling the chemicals, must be provided by industry to the European Chemicals Agency (ECHA) before the chemicals are allowed on the European market. The information is used by ECHA and the competent authorities of the Member States to identify chemicals of concern that warrant regulation. Thus, the registered data need to be reliable and relevant as well as transparently reported to ensure that chemicals of concern can be identified. The aim of this thesis was to provide insights into the risk assessments carried out by industry under REACH to contribute to a safer use of chemicals.

    The results in this thesis show that information that is used for concluding on hazards and risks of chemicals as well as industry’s conclusions are reported in a semi-transparent manner and therefore difficult for third parties to fully scrutinise and evaluate (paper I). This was in part due to the protection of confidential information as laid down by law but also related to ECHA’s procedures for making information available to the public as well as industry’s reporting. Furthermore, industry is only required under REACH to summarise (eco)toxicity studies that are gathered for the risk assessment. Consequently, data based on industry studies that are not publicly available cannot be scrutinised and independently assessed by third parties. Thus, the system relies on studies being accurately summarised by the registrant although this was not always seen to be the case (paper IV). 

    Furthermore, the current framework for industry to evaluate (eco)toxicity studies and report data evaluations under REACH was found to be neither systematic nor transparent (paper II). Studies may not be evaluated based on their inherent scientific quality when the Klimisch method for evaluating data is used, which is the recommended data evaluation method under REACH. Using the Klimisch method may also result in giving less weight to non-standard studies, such as many academic research studies, than studies performed according to standardised test guidelines, although non-standard studies could contribute with important information to the risk assessment. The structure and transparency of data evaluations could be improved by using a framework that has clear criteria and guidance as well as a structured format for reporting data evaluations (paper III). This would support more harmonised and transparent data evaluations and encourage studies to be evaluated according to their inherent scientific quality rather than mere compliance with standardised test guidelines.

    The overall objective of this thesis is to contribute to the development of systematic and transparent risk assessments under REACH, which is critical for using chemicals safely.

  • 305.
    Ingre-Khans, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Beronius, Anna
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reliability and relevance evaluations of REACH data2019In: Toxicology Research, ISSN 2045-452X, E-ISSN 2045-4538, Vol. 8, no 1, p. 46-56Article in journal (Refereed)
    Abstract [en]

    Regulatory authorities rely on hazard and risk assessments performed under REACH for identifying chemicals of concern and to take action. Therefore, these assessments must be systematic and transparent. This study investigates how registrants evaluate and report data evaluations under REACH and the procedures established by the European Chemicals Agency (ECHA) to support these data evaluations. Data on the endpoint repeated dose toxicity were retrieved from the REACH registration database for 60 substances. An analysis of these data shows that the system for registrants to evaluate data and report these evaluations is neither systematic nor transparent. First, the current framework focuses on reliability, but overlooks the equally important aspect of relevance, as well as how reliability and relevance are combined for determining the adequacy of individual studies. Reliability and relevance aspects are also confused in the ECHA guidance for read-across. Second, justifications for reliability evaluations were mainly based on studies complying with GLP and test guidelines, following the Klimisch method. This may result in GLP and guideline studies being considered reliable by default and discounting non-GLP and non-test guideline data. Third, the reported rationales for reliability were frequently vague, confusing and lacking information necessary for transparency. Fourth, insufficient documentation of a study was sometimes used as a reason for judging data unreliable. Poor reporting merely affects the possibility to evaluate reliability and should be distinguished from methodological deficiencies. Consequently, ECHA is urged to improve the procedures and guidance for registrants to evaluate data under REACH to achieve systematic and transparent risk assessments.

  • 306.
    Ingre-Khans, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Beronius, Anna
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Toxicity studies used in registration, evaluation, authorisation and restriction of chemicals (REACH): How accurately are they reported?2019In: Integrated Environmental Assessment and Management, ISSN 1551-3777, E-ISSN 1551-3793, Vol. 15, no 3, p. 458-469Article in journal (Refereed)
    Abstract [en]

    Toxicity studies on chemicals registered under the European Union's Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) regulation are provided as summaries instead of as a full study report. Because the registration data are used by regulatory agencies to identify chemicals of concern, the study summaries must accurately reflect the information in studies. A “study summary” should include sufficient information on the objectives, methods, results, and conclusions in the full study report in order for the relevance of the study to be determined. Sometimes a “robust study summary” is required, which should contain more detailed information to enable an independent assessment of the study. The aim of the present investigation is to examine how well published toxicity papers were reflected in study summaries submitted by registrants under REACH. Summaries of 20 published studies (peer‐reviewed studies, including 1 abstract) were examined and broad categories of various types of observed differences were derived. The extent to which information in the published studies was reported, as well as how accurately the information was reflected, varied. How accurately the information was reflected also varied. Differences between the published studies and the summaries included simple typing errors, unclear and incomplete reporting, as well as the omission of information on, for example, study design, results, or interpretation of the results, which in some cases could be considered relevant for the risk assessment. This raises concerns regarding the accuracy of study summaries and their use for decision making. Moreover, the possibility for third parties to independently assess and scrutinize the summaries is limited. Considering that we rely on REACH registration data for chemical safety, all data used for risk assessment should be accessible for thorough examination and fully independent assessment.

  • 307.
    Ingre-Khans, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Beronius, Anna
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Transparency of chemical risk assessment data under REACH2016In: Environmental Science: Pocesses & Impacts, ISSN 2050-7887, Vol. 18, no 12, p. 1508-1518Article in journal (Refereed)
    Abstract [en]

    The REACH regulation requires EU manufacturers and importers of substances to register information on the hazard and risk of their substances with the European Chemicals Agency (ECHA). Risk management of the substances is based on the provided information. It is known that conclusions on hazard and risk are influenced by expert judgements as well as potential conflict of interests. Thus, it is important that hazard and risk assessments are transparent and can be evaluated by a third party. The aim of this study is to scrutinize the transparency, i.e. the accessibility and comprehensibility, of information on substances registered under REACH. Data on repeated dose toxicity and hazard assessment conclusions were extracted for 60 substances from the REACH registration database available on the ECHA website. The data were compiled in a database for systematically evaluating the transparency of information related to the conclusions on hazard or risk. In addition, chemical safety reports (CSR) were requested from ECHA for five substances. The transparency of information on the hazard and risk of substances was found to be limited for several reasons. First, certain information was removed due to confidentiality and certain fields were not published because they could contain confidential information although the information had not been claimed confidential. Also, the extent to which registrants reported information varied, and the presentation of some data and certain terminology required further clarification. In addition, the data source for the majority of the key and supporting studies could not be identified due to confidentiality. Since registrants are only required to summarise studies, it cannot be verified whether all relevant information from non-public industry reports have been reported. Lastly, certain information related to the hazard and risk assessment were only reported in the CSR which is only available upon request; a time-consuming and work-intensive process. As information on registered chemicals is currently provided to the public, it is difficult to follow steps that are undertaken in the hazard and risk assessment. This limits the possibility for a third party to evaluate the assessment.

  • 308.
    Ingre-Khans, Ellen
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Beronius, Anna
    Improving structure and transparency in reliability evaluations of data under REACH – suggestions for a systematic methodIn: Article in journal (Refereed)
    Abstract [en]

    The goal of identifying hazardous chemicals registered under the REACH Regulation and taking appropriate risk management measures relies on robust data registrations. However, the current procedures for European chemical manufacturers and importers to evaluate data under REACH neither support systematic evaluations of data nor transparently communicate these assessments. The aim of this study was to explore how using a data evaluation method with predefined criteria for reliability and establishing principles for assigning reliability categories could contribute to more structured and transparent evaluations under REACH. In total, 20 peer-reviewed studies for 15 substances registered under REACH were selected for an in-depth evaluation of reliability with the SciRAP tool. The results show that using a method for study evaluation, with clear criteria for assessing reliability and assigning studies to reliability categories, contributes to more structured and transparent reliability evaluations. Consequently, it is recommended to implement a method for evaluating data under REACH with predefined criteria and fields for documenting and justifying the assessments to increase consistency of data evaluations and transparency.

  • 309.
    Islam, Farhana
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Victoria, Canada.
    Granot, Ori
    McIndoe, J. Scott
    Determination of n-Alkanes in Jet Fuel by Cold-electron Ionization Gas Chromatography-Mass Spectrometry2017In: Analytical Letters, ISSN 0003-2719, E-ISSN 1532-236X, Vol. 50, no 10, p. 1593-1601Article in journal (Refereed)
    Abstract [en]

    A rapid, easy, and reliable method was developed for the characterization of jet fuel with minimal sample preparation. A standard solution of 13 aliphatic n-alkanes in hexane was used to evaluate and validate the separation using cold-electron ionization gas chromatography-mass spectrometry. The method was evaluated and validated by the linearity, accuracy, and precision for all analytes. The limits of detection and quantification for each n-alkane were also evaluated. Nine major n-alkanes from n-octane to n-hexadecane were positively identified and quantified in jet fuel due to the enhanced molecular ion in the mass spectra. Major n-alkanes and their corresponding isomers in jet fuel were also identified from the extracted ion chromatograms. n-Undecane, n-dodecane, n-tridecane, and n-tetradecane were present at the highest concentrations in jet fuel at approximately 7% (v/v). The total concentrations of total straight chain alkanes were 34-37% in jet fuel that was comparable with the standard value of 32%.

  • 310.
    Ivansson, Milena Edith
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Stable chlorine isotope analysis of chlorinated acetic acids2016Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Chlorinated acetic acids (CAAs) constitute a group of polar organic compounds that are ubiquitous in the environment. Their environmental occurrence has been extensively studied but their sources are still not well constrained. Isotopic characterization of compounds found in the environment can provide additional information and allow their source apportionment. Previous studies indicate, however, that CAAs of industrial and natural origin may not be distinguishable by stable carbon isotope analysis only. This thesis presents an analytical method for stable chlorine isotope analysis of CAAs using gas chromatography/quadruple mass spectrometry (GC/qMS), for which systems are found in most laboratories. The method was cross-calibrated with an offline reference method and allows the determination of chlorine isotope signatures of CAAs with sample amounts as small as 10 pmol with good precisions of <1 ‰. With this method CAAs can be isotopically characterized at environmental relevant concentrations, in contrast to conventional offline methods were large sample requirements limit the application. This new method enables multi-element stable isotope analysis of CAAs and may help to identify and quantify sources of CAAs to the environment.

  • 311. Jaeger, Anna
    et al.
    Posselt, Malte
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Betterle, Andrea
    Schaper, Jonas
    Mechelke, Jonas
    Coll, Claudia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lewandowski, Joerg
    Spatial and Temporal Variability in Attenuation of Polar Organic Micropollutants in an Urban Lowland Stream2019In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, no 5, p. 2383-2395Article in journal (Refereed)
    Abstract [en]

    Contamination of rivers by trace organic compounds (TrOCs) poses a risk for aquatic ecosystems and drinking water quality. Spatially- and temporally varying environmental conditions are expected to play a major role in controlling in-stream attenuation of TrOCs. This variability is rarely captured by in situ studies of TrOC attenuation. Instead, snap-shots or time-weighted average conditions and corresponding attenuation rates are reported. The present work sought to investigate this variability and factors controlling it by analysis of 24 TrOCs over a 4.7 km reach of the River Erpe (Berlin, Germany). The factors investigated included sunlight and water temperature as well as the presence of macrophytes. Attenuation rate constants in 48 consecutive hourly water parcels were tracked along two contiguous river sections of different characteristics. Section 1 was less shaded and more densely covered with submerged macrophytes compared to section 2. The sampling campaign was repeated after macrophyte removal from section 1. The findings show, that section 1 generally provided more favorable conditions for both photo- and biodegradation. Macrophyte removal enhanced photolysis of some compounds (e.g., hydrochlorothiazide and diclofenac) while reducing the biodegradation of metoprolol. The transformation products metoprolol acid and valsartan acid were formed along the reach under all conditions.

  • 312. Jahnke, Annika
    et al.
    Arp, Hans Peter H.
    Escher, Beate I.
    Gewert, Berit
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kühnel, Dana
    Ogonowski, Martin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Aquabiota Water Research AB, Sweden.
    Potthoff, Annegret
    Rummel, Christoph
    Schmitt-Jansen, Mechthild
    Toorman, Erik
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reducing Uncertainty and Confronting Ignorance about the Possible Impacts of Weathering Plastic in the Marine Environment2017In: Environmental Science and Technology Letters, ISSN 2328-8930, Vol. 4, no 3, p. 85-90Article, review/survey (Refereed)
    Abstract [en]

    Plastic in the global oceans fulfills two of the three conditions for pollution to pose a planetary boundary threat because it is causing planetary-scale exposure that is not readily reversible. Plastic is a planetary boundary threat if it is having a currently unrecognized disruptive effect on a vital Earth system process. Discovering possible unknown effects is likely to be aided by achieving a fuller understanding of the environmental fate of plastic. Weathering of plastic generates microplastic, releases chemical additives, and likely also produces nanoplastic and chemical fragments cleaved from the polymer backbone. However, weathering of plastic in the marine environment is not well understood in terms of time scales for fragmentation and degradation, the evolution of particle morphology and properties, and hazards of the chemical mixture liberated by weathering. Biofilms that form and grow on plastic affect weathering, vertical transport, toxicity, and uptake of plastic by marine organisms and have been underinvestigated. Laboratory studies, monitoring, and models weathering on plastic debris are needed to reduce uncertainty in hazard and risk assessments for known and field of the impact of suspected adverse effects. However, scientists and decision makers must also recognize that plastic in the oceans may have unanticipated effects about which we are currently ignorant. Possible impacts that are currently unknown can be confronted by vigilant monitoring of plastic in the oceans and discovery-oriented research related to the possible effects of weathering plastic.

  • 313.
    Jahnke, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Helmholtz Centre for Environmental Research – UFZ, Germany.
    Holmbäck, Jan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Argelia Andersson, Rina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kierkegaard, Amelie
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mayer, Philipp
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Differences between Lipids Extracted from Five Species Are Not Sufficient To Explain Biomagnification of Nonpolar Organic Chemicals2015In: Environmental Science and Technology Letters, ISSN 2328-8930, Vol. 2, no 7, p. 193-197Article in journal (Refereed)
    Abstract [en]

    Lipids are the major sorptive phase for many organic chemicals that bioaccumulate in foodwebs. However, lipids are usually operationally defined by the extraction protocol. Large differences in sorptive capacities between species would violate assumptions implicit in widely used lipid-normalization procedures and invalidate generic bioaccumulation factors. We extracted lipids from five species from different trophic levels and domains and determined fractions of triglycerides, phospholipids, and cholesterol. We passively dosed the lipids with cyclic volatile methylsiloxanes and chlorobenzenes via headspace from spiked olive oil to determine their sorptive capacities. Lipids from seal blubber and pork bacon solely composed of triglycerides had capacities similar to that of olive oil; lipids from mussels, herring, and guillemot egg had quantifiable fractions of phospholipids and cholesterol and showed capacities reduced by factors of up to 2.3-fold. Generally, the sorptive capacities of the lipids were not elevated relative to the olive oil controls and are unlikely to explain a substantial part of biomagnification.

  • 314.
    Jahnke, Annika
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Helmholtz Centre for Environmental Research − UFZ, Germany.
    Mayer, Philipp
    Schäfer, Sabine
    Witt, Gesine
    Haase, Nora
    Escher, Beate I.
    Strategies for Transferring Mixtures of Organic Contaminants from Aquatic Environments into Bioassays2016In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, no 11, p. 5424-5431Article in journal (Refereed)
    Abstract [en]

    Mixtures of organic contaminants are ubiquitous ronment. Depending on their persistence and physicochemical properties, individual chemicals that make up the mixture partition and distribute within the environment and might then jointly elicit toxicological effects. For the assessment and monitoring of such mixtures, a variety of cell-based in vitro and low-complexity in vivo bioassays based on algae, daphnids or fish embryos are available. A very important and sometimes unrecognized challenge is how to combine sampling, extraction and dosing to transfer the mixtures from the environment into bioassays, while conserving (or re-establishing) their chemical composition at adjustable levels for concentration-effect assessment. This article outlines various strategies for quantifiable transfer from environmental samples including water, sediment, and biota into bioassays using total extraction or polymer-based passive sampling combined with either solvent spiking or passive dosing.

  • 315. Jahnke, Annika
    et al.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergmann, Melanie
    Bräunig, Jennifer
    Landmann, Madlen
    Schäfer, Sabine
    Escher, Beate I.
    Emerging investigator series: effect-based characterization of mixtures of environmental pollutants in diverse sediments2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 12, p. 1667-1679Article in journal (Refereed)
    Abstract [en]

    This study investigated whether cell-based bioassays were suitable to characterize profiles of mixture effects of hydrophobic pollutants in multiple sediments covering remote Arctic and tropical sites to highly populated sites in Europe and Australia. The total contamination was determined after total solvent extraction and the bioavailable contamination after silicone-based passive equilibrium sampling. In addition to cytotoxicity, we observed specific responses in cell-based reporter gene bioassays: activation of metabolic enzymes (arylhydrocarbon receptor: AhR, peroxisome proliferator activated receptor gamma: PPAR) and adaptive stress responses (oxidative stress response: AREc32). No mixture effects were found for effects on the estrogen, androgen, progesterone and glucocorticoid receptors, or they were masked by cytotoxicity. The bioanalytical equivalent concentrations (BEQ) spanned several orders of magnitude for each bioassay. The bioavailable BEQs (passive equilibrium sampling) typically were 10-100 times and up to 420 times lower than the total BEQ (solvent extraction) for the AhR and AREc32 assays, indicating that the readily desorbing fraction of the bioactive chemicals was substantially lower than the fraction bound strongly to the sediment sorptive phases. Contrarily, the bioavailable BEQ in the PPAR assay was within a factor of five of the total BEQ. We identified several hotspots of contamination in Europe and established background contamination levels in the Arctic and Australia.

  • 316.
    Jakobsson, Martin
    et al.
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Nilsson, Johan
    Stockholm University, Faculty of Science, Department of Meteorology .
    Anderson, Leif
    Backman, Jan
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Björk, Göran
    Cronin, Thomas M.
    Kirchner, Nina
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Koshurnikov, Andrey
    Mayer, Larry
    Noormets, Riko
    O'Regan, Matthew
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Stranne, Christian
    Stockholm University, Faculty of Science, Department of Geological Sciences. University of New Hampshire, USA.
    Ananiev, Roman
    Barrientos Macho, Natalia
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Cherniykh, Denis
    Coxall, Helen
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Eriksson, Björn
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Flodén, Tom
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Gemery, Laura
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jerram, Kevin
    Johansson, Carina
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Khortov, Alexey
    Mohammad, Rezwan
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Semiletov, Igor
    Evidence for an ice shelf covering the central Arctic Ocean during the penultimate glaciation2016In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 7, article id 10365Article in journal (Refereed)
    Abstract [en]

    The hypothesis of a km-thick ice shelf covering the entire Arctic Ocean during peak glacial conditions was proposed nearly half a century ago. Floating ice shelves preserve few direct traces after their disappearance, making reconstructions difficult. Seafloor imprints of ice shelves should, however, exist where ice grounded along their flow paths. Here we present new evidence of ice-shelf groundings on bathymetric highs in the central Arctic Ocean, resurrecting the concept of an ice shelf extending over the entire central Arctic Ocean during at least one previous ice age. New and previously mapped glacial landforms together reveal flow of a spatially coherent, in some regions41-km thick, central Arctic Ocean ice shelf dated to marine isotope stage 6 (similar to 140 ka). Bathymetric highs were likely critical in the ice-shelf development by acting as pinning points where stabilizing ice rises formed, thereby providing sufficient back stress to allow ice shelf thickening.

  • 317.
    Jamshidi, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Kharazmi University, Iran.
    Rofouei, Mohammad Kazem
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. IVL Swedish Environmental Research Institute, Sweden.
    Using magnetic core-shell nanoparticles coated with an ionic liquid dispersion assisted by effervescence powder for the micro-solid-phase extraction of four beta blockers from human plasma by ultra high performance liquid chromatography with mass spectrometry detection2019In: Journal of Separation Science, ISSN 1615-9306, E-ISSN 1615-9314, Vol. 42, no 3, p. 698-705Article in journal (Refereed)
    Abstract [en]

    In this work, a novel, efficient, and green sorbent, SiO2@Fe3O4 has been created and functionalized with 1-butyl-3-methylimidazolium hexafluorophosphate as an ionic liquid. This sorbent was applied for microextraction of four beta blockers, propranolol, metoprolol, atenolol, and alprenolol with bupivacaine as internal standard from human plasma followed by liquid chromatography with mass spectrometric detection. A mixture of sodium bicarbonate and sodium dihydrogen phosphate was used as an extractant dispersive agent (effervescent power) to enhance the interaction between the magnetic sorbent and analytes. Main affecting parameters on microextraction and elution were optimized. Figures of merit for dispersive solid phase extraction with ionic liquid coated magnetic nanoparticles assisted by effervescent powder were calculated under the optimized conditions. The detection limits for propranolol, metoprolol, atenolol, and alprenolol were found at 0.33, 0.62, 0.03, and 0.44 ng/mL, respectively. For all analytes, good linearity was obtained. Intra-(n = 5) and interday (n = 10) precision were both under 6.3% while the preconcentration factors were obtained in the range between 15-18. The extraction efficiencies for each analyte ranged from 75 to 91%. The method was successfully applied for determination of trace amounts of the beta blockers in human plasma samples.

  • 318. Jantunen, Liisa M.
    et al.
    Wong, Fiona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gawor, Anya
    Kylin, Henrik
    Helm, Paul A.
    Stern, Gary A.
    Strachan, William M. J.
    Burniston, Deborah A.
    Bidleman, Terry F.
    20 Years of Air-Water Gas Exchange Observations for Pesticides in the Western Arctic Ocean2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 23, p. 13844-13852Article in journal (Refereed)
    Abstract [en]

    The Arctic has been contaminated by legacy organochlorine pesticides (OCPs) and currently used pesticides (CUPs) through atmospheric transport and oceanic currents. Here we report the time trends and air-water exchange of OCPs and CUPs from research expeditions conducted between 1993 and 2013. Compounds determined in both air and water were trans- and cis-chlordanes (TC, CC), trans- and cis-nonachlors (TN, CN), heptachlor exo-epoxide (HEPX), dieldrin (DEL), chlorobomanes (Sigma CHBs and toxaphene), dacthal (DAC), endosulfans and metabolite endosulfan sulfate (ENDO-I, ENDO-II, and ENDO SUL), chlorothalonil (CHT), chlorpyrifos (CPF), and trifluralin (TFN). Pentachloronitrobenzene (PCNB and quintozene) and its soil metabolite pentachlorothianisole (PCTA) were also found in air. Concentrations of most OCPs declined in surface water, whereas some CUPs increased (ENDO-I, CHT, and TFN) or showed no significant change (CPF and DAC), and most compounds declined in air. Chlordane compound fractions TC/(TC + CC) and TC/(TC + CC + TN) decreased in water and air, while CC/(TC + CC + TN) increased. TN/(TC + CC + TN) also increased in air and slightly, but not significantly, in water. These changes suggest selective removal of more labile TC and/or a shift in chlordane sources. Water air fugacity ratios indicated net volatilization (FR > 1.0) or near equilibrium (FR not significantly different from 1.0) for most OCPs but net deposition (FR < 1.0) for Sigma CHBs. Net deposition was shown for ENDO-I on all expeditions, while the net exchange direction of other CUPs varied. Understanding the processes and current state of air surface exchange helps to interpret environmental exposure and evaluate the effectiveness of international protocols and provides insights for the environmental fate of new and emerging chemicals.

  • 319.
    Jiang, Liying
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mass Spectrometry of Non-protein Amino Acids: BMAA and Neurodegenerative Diseases2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Neurodegenerative diseases have been shown to correlate positively with an ageing population. The most common neurodegenerative diseases are amyotrophic lateral sclerosis (ALS), Parkinson’s disease and Alzheimer’s disease. The cause of these diseases is believed to be the interaction between genetic and environmental factors, synergistically acting with ageing. BMAA (β-methylamino-L-alanine) is one kind of toxin present in our environment and might play an important role in the development of those diseases.

    BMAA was initially isolated from cycad seeds in Guam, where the incidence of ALS/Parkinsonism-dementia complex among the indigenous people was 50 – 100 times higher than the rest of the world in the 1950’s. BMAA can induce toxic effects on rodents and primates. Furthermore, it can potentiate neuronal injury on cell cultures at concentrations as low as 10 µM. BMAA was reported to be produced by cyanobacteria, and could bio-magnify through the food chain.

    In this thesis, work was initially focused on the improvement of an existing analytical method for BMAA identification and quantification using liquid chromatography coupled with tandem mass spectrometry.  Subsequently, the refined method was applied to environmental samples for probing alternative BMAA producer(s) in nature and to seafood samples for estimation of human exposure to this toxin.

    In Paper I, a systematic screening of the isomers of BMAA in a database was performed and seven potential isomers were suggested. Three of them were detected or suspected in natural samples. In Paper II, a deuterated internal standard was synthesized and used for quantifying BMAA in cyanobacteria. In Paper III, Diatoms were discovered to be a BMAA producer in nature. In Paper IV, ten popular species of seafood sold in Swedish markets were screened for BMAA. Half of them were found to contain BMAA at a level of 0.01 – 0.90 µg/g wet weight. In Future perspectives, the remaining questions important in this field are raised.

  • 320.
    Johansson, Christer
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Environment and Health Administration, SLB, Sweden.
    Lövenheim, Boel
    Schantz, Peter
    Wahlgren, Lina
    Almström, Peter
    Markstedt, Anders
    Strömgren, Magnus
    Forsberg, Bertil
    Nilsson Sommar, Johan
    Impacts on air pollution and health by changing commuting from car to bicycle2017In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 584, p. 55-63Article in journal (Refereed)
    Abstract [en]

    Our study is based on individual data on people's home and work addresses, as well as their age, sex and physical capacity, in order to establish realistic bicycle-travel distances. A transport model is used to single out data on commuting preferences in the County Stockholm. Our analysis shows there is a very large potential for reducing emissions and exposure if all car drivers living within a distance corresponding to a maximum of a 30 min bicycle ride to work would change to commuting by bicycle. It would result in >111,000 new cyclists, corresponding to an increase of 209% compared to the current situation. Mean population exposure would be reduced by about 7% for both NOx and black carbon (BC) in the most densely populated area of the inner city of Stockholm. Applying a relative risk for NOx of 8% decrease in all-cause mortality associated with a 10 mu g m(-3) decrease in NOx, this corresponds to >449 (95% CI: 340-558) years of life saved annually for the Stockholm county area with 2.1 million inhabitants. This is more than double the effect of the reduced mortality estimated for the introduction of congestion charge in Stockholm in 2006. Using NO2 or BC as indicator of health impacts, we obtain 395 (95% CI: 172-617) and 185 (95% CI: 158-209) years of life saved for the population, respectively. The calculated exposure of BC and its corresponding impacts on mortality are likely underestimated. With this in mind the estimates using NOx, NO2 and BC show quite similar health impacts considering the 95% confidence intervals.

  • 321.
    Johansson, Jana
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University.
    Sources, transport and fate of perfluoroalkyl acids in the atmosphere2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Perfluoroalkyl acids (PFAAs) are man-made chemicals which have been observed in the global environment, even in locations far away from where they are emitted. These persistent substances are taken up in humans and biota and may have toxic effects. Knowledge about how PFAAs are dispersed in the environment is needed to discern strategies to manage their sources and to evaluate the efficacy of adopted legislation. This thesis aimed to increase our understanding of the sources of PFAAs to the atmosphere and how PFAAs are transported in air. The results of Paper I demonstrated that gaseous perfluorooctanoic acid (PFOA) sorbs to typical glass fibre filters (GFFs) used in high-volume air sampling of PFAAs. As a consequence, the fraction of gaseous PFOA present in sampled air is underestimated, while the fraction of PFOA associated with aerosols is overestimated. Replacing GFFs with filters deactivated through silanisation and siliconisation did not eliminate this sampling artefact and is therefore not recommended as a means to determine the gas-particle partitioning of PFAAs. In Paper II, monitoring of the mass of PFOA transferred from water solutions of pH 0.2-5.5 demonstrated that the acid dissociation constant of linear PFOA and the four most ubiquitous branched PFOA isomers is around or below 1. Furthermore, the results demonstrated that the presence of counter ions and organic matter in water retarded, rather than enhanced, the volatilisation of PFOA. Therefore, volatilisation of all isomers of PFOA from environmental waters is expected to be negligible. To further study the transfer of PFAAs from environmental waters to air, Paper III simulated the process of sea spray generation in the laboratory. Strong enrichment of PFAAs was observed from bulk water to the surface microlayer and to aerosols. The enrichment increased with PFAA chain length, indicating that this process is of greater importance for more surface active substances. The highest enrichment was observed in aerosols < 1.6 µm, which can travel over long distances if not rained out. Based on the measured aerosol enrichment factors we estimated that approximately 70 metric tonnes of PFAAs are aerosolised from the global oceans yearly and that 3% of this mass is deposited in terrestrial environments. Paper IV reported the occurrence of branched PFOA isomers in deposition sampled in five geographical locations. The presence of these isomers demonstrated that atmospheric transformation of fluorotelomer alcohols is not the only ongoing source of PFAAs to air. We hypothesised that, additionally, both sea spray aerosols and direct emissions from manufacturing sources contributed to the contamination of the precipitation on different spatial scales. Although further research is required to determine the relative importance of different sources to the atmosphere locally and globally, this thesis has substantially advanced the state-of-the-science by i) demonstrating the significance of an air sampling artefact discussed as an uncertainty in the scientific literature over the past decade, ii) definitively ruling out volatilisation from environmental waters as a source of PFOA to air, iii) demonstrating transfer of PFAAs from seawater to air via sea spray aerosols and thus quantifying the environmental importance of this process, and iv) ultimately demonstrating that several types of sources of PFAAs impact the global atmosphere and thus PFAA contamination patterns in precipitation.

  • 322.
    Johansson, Jana H.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Berger, Urs
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Can the use of deactivated glass fibre filters eliminate sorption artefacts associated with active air sampling of perfluorooctanoic acid?2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 224, p. 779-786Article in journal (Refereed)
    Abstract [en]

    Experimental work was undertaken to test whether gaseous perfluorooctanoic acid (PFOA) sorbs to glassfibre filters (GFFs) during air sampling, causing an incorrect measure of the gas-particle equilibriumdistribution. Furthermore, tests were performed to investigate whether deactivation by siliconisationprevents sorption of gaseous PFOA to filter materials. An apparatus was constructed to closely simulate ahigh-volume air sampler, although with additional features allowing introduction of gaseous test compoundsinto an air stream stripped from particles. The set-up enabled investigation of the sorption ofgaseous test compounds to filter media, eliminating any contribution from particles. Experiments wereperformed under ambient outdoor air conditions at environmentally relevant analyte concentrations.The results demonstrate that gaseous PFOA sorbs to GFFs, but that breakthrough of gaseous PFOA on theGFFs occurs at trace-level loadings. This indicates that during high volume air sampling, filters do notquantitatively capture all the PFOA in the sampled air. Experiments with siliconised GFFs showed thatthis filter pre-treatment reduced the sorption of gaseous PFOA, but that sorption still occurred atenvironmentally relevant air concentrations. We conclude that deactivation of GFFs does not allow forthe separation of gaseous and particle bound perfluorinated carboxylic acids (PFCAs) during active airsampling. Consequently, the well-recognised theory that PFCAs do not prevail as gaseous species in theatmosphere may be based on biased measurements. Caution should be taken to ensure that this artefactwill not bias the conclusions of future field studies.

  • 323.
    Johansson, Jana H.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Salter, Matthew E.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Acosta Navarro, Juan Camilo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nilsson, E. Douglas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Global transport of perfluoroalkyl acids via sea spray aerosol2019In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, no 4, p. 635-649Article in journal (Refereed)
    Abstract [en]

    Perfluoroalkyl acids (PFAAs) are persistent organic pollutants found throughout the world's oceans. Previous research suggests that long-range atmospheric transport of these substances may be substantial. However, it remains unclear what the main sources of PFAAs to the atmosphere are. We have used a laboratory sea spray chamber to study water-to-air transfer of 11 PFAAs via sea spray aerosol (SSA). We observed significant enrichment of all PFAAs relative to sodium in the SSA generated. The highest enrichment was observed in aerosols with aerodynamic diameter < 1.6 mm, which had aerosol PFAA concentrations up to similar to 62 000 times higher than the PFAA water concentrations in the chamber. In surface microlayer samples collected from the sea spray chamber, the enrichment of the substances investigated was orders of magnitude smaller than the enrichment observed in the aerosols. In experiments with mixtures of structural isomers, a lower contribution of branched PFAA isomers was observed in the surface microlayer compared to the bulk water. However, no clear trend was observed in the comparison of structural isomers in SSA and bulk water. Using the measured enrichment factors of perfluorooctanoic acid and perfluorooctane sulfonic acid versus sodium we have estimated global annual emissions of these substances to the atmosphere via SSA as well as their global annual deposition to land areas. Our experiments suggest that SSA may currently be an important source of these substances to the atmosphere and, over certain areas, to terrestrial environments.

  • 324.
    Johansson, Jana H.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Shi, Yali
    Salter, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of isomer patterns2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 7, p. 997-1006Article in journal (Refereed)
    Abstract [en]

    To evaluate the relevance of different proposed sources of perfluoroalkyl acids (PFAAs) to air, their isomer patterns were analyzed in deposition samples collected from five geographical locations: two urban sites in China (>360 km from known operational fluorochemical manufacturing facilities), one remote marine site in the Azores archipelago and two Swedish sites representing urban and background conditions. Despite variable contributions from linear perfluorooctanoic acid (PFOA) in the samples, the pattern of branched PFOA isomers was similar to those of technical standards manufactured using electrochemical fluorination (ECF). This indicates that atmospheric fate processes have little influence on the isomer profiles of PFOA and that the relative contribution of PFOA manufactured using ECF (typically 20-26% branched isomers) and telomerization (typically one single linear isomer) can be determined in atmospheric deposition samples by analyzing the proportions of branched and linear isomers. In Chinese samples, branched isomers contributed 15-25% to the total loading of PFOA, indicating that the samples were dominated by ECF PFOA. Samples in the Azores had 8-10% contribution from branched PFOA isomers, indicating an approximately equal influence of ECF and telomer sources. Only three of the samples collected in Sweden displayed a quantifiable contribution from branched PFOA isomers (8-13% of overall PFOA loading in the samples). One branched PFNA isomer was observed in samples from the marine sites. Direct manufacturing discharges, transport of sea spray aerosols and degradation of precursors are all suggested to be contributing sources, albeit to different extents, to PFAAs in air at the different geographical locations where precipitation was sampled.

  • 325.
    Johansson, Jana H.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yan, Hong
    Berger, Urs
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Water-to-air transfer of branched and linear PFOA: Influence of pH, concentration and water type2017In: Emerging Contaminants, ISSN 2405-6650, E-ISSN 2405-6642, Vol. 3, no 1, p. 46-53Article in journal (Refereed)
    Abstract [en]

    The volatilisation of perfluorooctanoic acid (PFOA) was measured experimentally at a range of pH valuesusing a previously published laboratory method. Water-to-air transfer was studied for five structuralisomers, namely: the linear isomer (n-PFOA) and the four most commonly occurring branched isomers(3-, 4-, 5- and 6-PFOA). The influence of water concentration and water type on the pH-dependent waterto-air transfer was also investigated for n-PFOA. The water-to-air transfer was studied over the course of 48 h at pH values ranging from 0.2 to 5.5. Under all experimental conditions tested, the volatilisation ofPFOA was negligible at pH > 2.5. In experiments performed with MilliQ water, volatilisation increasedwith decreasing water pH. In experiments performed with tap water and lake water, maximum volatilisationwas observed at pH 1. The concentration of PFOA in water had no influence on the pH value atwhich water-to-air transfer was observed (i.e. at pH < 2.5) for the concentration range tested (0.1e50 mg/L PFOA in deionised water). Although the percentage of PFOA volatilised was significantly different forthe four branched isomers at low pH, volatilisation was not observed above pH 2.5 for any branchedisomer suggesting that all PFOA isomers have a low pKa. Overall, these laboratory results demonstratethat volatilisation of any structural isomer of PFOA from water is negligible at environmentally-relevantconditions. It is unlikely that PFOA isomers will be fractionated in the environment as a result of volatilisationbecause it is a process of negligible environmental relevance.

  • 326.
    Johansson, Jana
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Salter, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Navarro, Juan-Camilo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nilsson, Douglas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cousins, Ian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Global transport of perfluoroalkyl acids via sea spray aerosolManuscript (preprint) (Other academic)
  • 327.
    Johansson, Jana
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Shi, Yali
    Cousins, Ian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Spatial variation in the atmospheric deposition of perfluoroalkyl acids: source elucidation through analysis of homologue and isomer patternsManuscript (preprint) (Other academic)
    Abstract [en]

    To evaluate the relevance of different proposed sources of perfluoroalkyl acids (PFAAs) to air, PFAA homologue and isomer patterns were analysed in precipitation collected from five geographical locations suspected to be influenced by these different types of sources. In Chinese samples, perflourooctanoic acid (PFOA) dominated the homologue patterns with concentrations exceeding those observed in European samples by a factor of 2-59. Furthermore, the isomer pattern of PFOA in Chinese samples was close to that of technical standards for PFOA manufactured using electrochemical fluorination (ECF). This finding suggests that direct manufacturing emissions of PFOA to air dominate the loading of PFOA in air in these regions of China. The PFAA homologue pattern observed in precipitation sampled in Stockholm was dominated by perfluorohexanoic acid, perfluorononanoic acid (PFNA) and PFOA. The isomer pattern of PFOA was to a large degree linear indicating that telomer-based sources, i.e. most likely atmospheric degradation of fluorotelomer alcohols, dominate in this urban area. Samples from the Azores, a group of islands located in the open Atlantic, were dominated by perfluorooctane sulfonic acid (PFOS), PFNA and PFOA, which displayed an isomer patttern suggestive of input from both ECF and telomer sources. A similar pattern was observed in precipitation collected during winter months at a rural site on the Swedish west coast, while samples taken at this site during summer displayed homologue and isomer patterns more like those observed in Stockholm. We hypothesize that the contribution from ECF PFOA observed in European samples was due to influence from sea spray aerosols and this requires further detailed investigation.

  • 328.
    Julin, Jan
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Eastern Finland, Finland.
    Murphy, Benjamin N.
    Patoulias, David
    Fountoukis, Christos
    Olenius, Tinja
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Pandis, Spyros N.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Impacts of Future European Emission Reductions on Aerosol Particle Number Concentrations Accounting for Effects of Ammonia, Amines, and Organic Species2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 2, p. 692-700Article in journal (Refereed)
    Abstract [en]

    Although they are currently unregulated, atmospheric ultrafine particles (<100 nm) pose health risks because of, e.g., their capability to penetrate deep into the respiratory system. Ultrafine particles, often minor contributors to atmospheric particulate mass, typically dominate aerosol particle number concentrations. We simulated the response of particle number concentrations over Europe to recent estimates of future emission reductions of aerosol particles and their precursors. We used the chemical transport model PMCAMx-UF, with novel updates including state-of-the-art descriptions of ammonia and dimethylamine new particle formation (NPF) pathways and the condensation of organic compounds onto particles. These processes had notable impacts on atmospheric particle number concentrations. All three emission scenarios (current legislation, optimized emissions, and maximum technically feasible reductions) resulted in substantial (10-50%) decreases in median particle number concentrations over Europe. Consistent reductions were predicted in Central Europe, while Northern Europe exhibited smaller reductions or even increased concentrations. Motivated by the improved NPF descriptions for ammonia and methylamines, we placed special focus on the potential to improve air quality by reducing agricultural emissions,, which are a major source of these species. Agricultural emission controls showed promise in reducing ultrafine particle number concentrations, although the change is nonlinear with particle size.

  • 329. Jung, Chang Hoon
    et al.
    Yoon, Young Jun
    Kang, Hyo Jin
    Gim, Yeontae
    Lee, Bang Yong
    Ström, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Krejci, Radovan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tunved, Peter
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    The seasonal characteristics of cloud condensation nuclei (CCN) in the arctic lower troposphere2018In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 70, no 1, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Cloud Condensation Nuclei (CCN) concentration and aerosol size distributions in the Arctic were collected during the period 2007-2013 at the Zeppelin observatory (78.91 degrees N, 11.89 degrees E, 474 masl). Annual median CCN concentration at a supersaturation (SS) of 0.4% show the ranges of 45 approximate to 81cm(-3). The monthly median CCN number density varied between 17cm(-3) in October 2007 and 198cm(-3) in March, 2008. The CCN spectra parameters C (83cm(-3)) and k (0.23) were derived. In addition, calculated annual median value of hygroscopicity parameter is 0.46 at SS of 0.4%. Particle number concentration of accumulation mode from aerosol size distribution measurements are well correlated with CCN concentration. The CCN to CN>10 nm (particle number concentration larger than 10nm in diameter) ratio shows a maximum during March and minimum during July. The springtime high CCN concentration is attributed to high load of accumulation mode aerosol transported from the mid-latitudes, known as Arctic Haze. CCN concentration remains high also during Arctic summer due to the source of new CCN through particle formation followed by consecutive aerosol growth. Lowest aerosol as well as CCN number densities were observed during Arctic autumn and early winter when aerosol formation in the Arctic and long-range transport into the Arctic are not effective.

  • 330. Kademoglou, Aikaterinin
    et al.
    Giovanoulis, Georgios
    Magnér, Jörgen
    Collins, Chris
    de Wit, Cynthia
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In vitro bioaccessibility of plasticisers in indoor dust using simulated lung fluids2016Conference paper (Refereed)
  • 331. Kademoglou, Katerina
    et al.
    Giovanoulis, Georgios
    Palm-Cousins, Anna
    Padilla-Sanchez, Juan Antonio
    Magnér, Jörgen
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Collin, Christopher D.
    In Vitro Inhalation Bioaccessibility of Phthalate Esters and Alternative Plasticizers Present in Indoor Dust Using Artificial Lung Fluids2018In: Environmental Science and Technology Letters, E-ISSN 2328-8930, Vol. 5, no 6, p. 329-334Article in journal (Refereed)
    Abstract [en]

    Phthalate esters (PEs) are used as plasticizers in consumer products. Their low migration stability has resulted in the classification of PEs as major indoor contaminants. Because of PE's ubiquity and adverse health effects on humans and especially children, non-phthalate alternative plasticizers have been introduced into the market. This is the first study of in vitro inhalation bioaccessibility of PEs (e.g., DMP, DEP, and DEHP) and alternative plasticizers (e.g., DEHT and DINCH) via indoor dust to assess inhalation as an alternative route of exposure. Two artificial lung fluids were used, mimicking two distinctively different pulmonary environments: (1) artificial lysosomal fluid (ALF, pH 4.5) representing the intracellular acidic lung fluid inhaled particle contact after phagocytosis by alveolar macrophages and (2) Gamble's solution (pH 7.4), the extracellular healthy fluid for deep lung deposition of dust. DMP and DEP were highly bioaccessible (>75%), whereas highly hydrophobic compounds such as DEHP, DINCH, and DEHT were <5% bioaccessible via both artificial lung fluids. Our findings show that the inhalation bioaccessibility of PEs is primarily governed by their hydrophobicity and water solubility. Further research is necessary to develop unified and biologically relevant inhalation bioaccessibility tests, employed as part of human risk assessment of volatile and semivolatile organic pollutants.

  • 332. Kaiser, Sonja
    et al.
    Goeckede, Mathias
    Castro-Morales, Karel
    Knoblauch, Christian
    Ekici, Altug
    Kleinen, Thomas
    Zubrzycki, Sebastian
    Sachs, Torsten
    Wille, Christian
    Beer, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Process-based modelling of the methane balance in periglacial landscapes (JSBACH-methane)2017In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 10, no 1, p. 333-358Article in journal (Refereed)
    Abstract [en]

    A detailed process-based methane module for a global land surface scheme has been developed which is general enough to be applied in permafrost regions as well as wetlands outside permafrost areas. Methane production, oxidation and transport by ebullition, diffusion and plants are represented. In this model, oxygen has been explicitly incorporated into diffusion, transport by plants and two oxidation processes, of which one uses soil oxygen, while the other uses oxygen that is available via roots. Permafrost and wetland soils show special behaviour, such as variable soil pore space due to freezing and thawing or water table depths due to changing soil water content. This has been integrated directly into the methane-related processes. A detailed application at the Samoylov polygonal tundra site, Lena River Delta, Russia, is used for evaluation purposes. The application at Samoylov also shows differences in the importance of the several transport processes and in the methane dynamics under varying soil moisture, ice and temperature conditions during different seasons and on different microsites. These microsites are the elevated moist polygonal rim and the depressed wet polygonal centre. The evaluation shows sufficiently good agreement with field observations despite the fact that the module has not been specifically calibrated to these data. This methane module is designed such that the advanced land surface scheme is able to model recent and future methane fluxes from periglacial landscapes across scales. In addition, the methane contribution to carbon cycle-climate feedback mechanisms can be quantified when running coupled to an atmospheric model.

  • 333. Kaldmae, Margit
    et al.
    Österlund, Nicklas
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lianoudaki, Danai
    Sahin, Cagla
    Bergman, Peter
    Nyman, Tomas
    Kronqvist, Nina
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Allison, Timothy M.
    Marklund, Erik G.
    Landreh, Michael
    Gas-Phase Collisions with Trimethylamine-N-Oxide Enable Activation-Controlled Protein Ion Charge Reduction2019In: Journal of the American Society for Mass Spectrometry, ISSN 1044-0305, E-ISSN 1879-1123, Vol. 30, no 8, p. 1385-1388Article in journal (Refereed)
    Abstract [en]

    Modulating protein ion charge is a useful tool for the study of protein folding and interactions by electrospray ionization mass spectrometry. Here, we investigate activation-dependent charge reduction of protein ions with the chemical chaperone trimethylamine-N-oxide (TMAO). Based on experiments carried out on proteins ranging from 4.5 to 35kDa, we find that when combined with collisional activation, TMAO removes approximately 60% of the charges acquired under native conditions. Ion mobility measurements furthermore show that TMAO-mediated charge reduction produces the same end charge state and arrival time distributions for native-like and denatured protein ions. Our results suggest that gas-phase collisions between the protein ions and TMAO result in proton transfer, in line with previous findings for dimethyl- and trimethylamine. By adjusting the energy of the collisions experienced by the ions, it is possible to control the degree of charge reduction, making TMAO a highly dynamic charge reducer that opens new avenues for manipulating protein charge states in ESI-MS and for investigating the relationship between protein charge and conformation.

  • 334. Karl, Matthias
    et al.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Mashayekhy Rad, Farshid
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Backlund, Are
    Lopez-Aparicio, Susana
    Heintzenberg, Jost
    New insights in sources of the sub-micrometre aerosol at Mt. Zeppelin observatory (Spitsbergen) in the year 20152019In: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 71, no 1, p. 1-29Article in journal (Refereed)
    Abstract [en]

    In order to evaluate the potential impact of the Arctic anthropogenic emission sources it is essential to understand better the natural aerosol sources of the inner Arctic and the atmospheric processing of the aerosols during their transport in the Arctic atmosphere. A 1-year time series of chemically specific measurements of the sub-micrometre aerosol during 2015 has been taken at the Mt. Zeppelin observatory in the European Arctic. A source apportionment study combined measured molecular tracers as source markers, positive matrix factorization, analysis of the potential source distribution and auxiliary information from satellite data and ground-based observations. The annual average sub-micrometre mass was apportioned to regional background secondary sulphate (56%), sea spray (17%), biomass burning (15%), secondary nitrate (5.8%), secondary marine biogenic (4.5%), mixed combustion (1.6%), and two types of marine gel sources (together 0.7%). Secondary nitrate aerosol mainly contributed towards the end of summer and during autumn. During spring and summer, the secondary marine biogenic factor reached a contribution of up to 50% in some samples. The most likely origin of the mixed combustion source is due to oil and gas extraction activities in Eastern Siberia. The two marine polymer gel sources predominantly occurred in autumn and winter. The small contribution of the marine gel sources at Mt. Zeppelin observatory in summer as opposed to regions closer to the North Pole is attributed to differences in ocean biology, vertical distribution of phytoplankton, and the earlier start of the summer season.

  • 335. Karl, Matthias
    et al.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Mashayekhy Rad, Farshid
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bäcklund, Are
    Lopez-Aparicio, Susana
    Heintzenberg, Jost
    Sources of the sub-micrometre aerosol at Mt. Zeppelin Observatory (Spitsbergen) in the year 2015: Indication for ice-related marinegelsManuscript (preprint) (Other academic)
  • 336.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Duberg, Jon
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Motwani, Nisha H.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Hogfors, Hedvig
    Klawonn, Isabell
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Ploug, Helle
    Barthel Svedén, Jennie
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Garbaras, Andrius
    Sundelin, Brita
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hajdu, Susanna
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Larsson, Ulf
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs2015In: Ambio, ISSN 0044-7447, E-ISSN 1654-7209, Vol. 44, p. 413-426Article in journal (Refereed)
    Abstract [en]

    Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N-2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.

  • 337.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Do deposit-feeders compete? Isotopic niche analysis of an invasion in a species-poor system2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 9715Article in journal (Refereed)
    Abstract [en]

    Successful establishment of invasive species is often related to the existence of vacant niches. Competition occurs when invaders use the same limiting resources as members of the recipient community, which will be reflected in some overlap of their trophic niches. The concept of isotopic niche has been used to study trophic niche partitioning among species. Here, we present a two-year field study comparing isotopic niches of the deposit-feeding community in a naturally species-poor system. The isotopic niche analyses showed no overlap between a recent polychaete invader and any of the native species suggesting that it has occupied a vacant niche. Its narrow isotopic niche suggests specialized feeding, however, the high delta N-15 values compared to natives are most likely due to isotope fractionation effects related to nitrogen recycling and a mismatch between biological stoichiometry of the polychaete and the sediment nitrogen content. Notably, highly overlapping isotopic niches were inferred for the native species, which is surprising in a food-limited system. Therefore, our results demonstrate that invaders may broaden the community trophic diversity and enhance resource utilization, but also raise questions about the congruence between trophic and isotopic niche concepts and call for careful examination of assumptions underlying isotopic niche interpretation.

  • 338.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Niemand, Clarisse
    Savage, Candida
    Pilditch, Conrad A.
    Density of Key-Species Determines Efficiency of Macroalgae Detritus Uptake by Intertidal Benthic Communities2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 7, article id e0158785Article in journal (Refereed)
    Abstract [en]

    Accumulating evidence shows that increased biodiversity has a positive effect on ecosystem functioning, but the mechanisms that underpin this positive relationship are contentious. Complete extinctions of regional species pools are comparatively rare whereas compositional changes and reductions in abundance and biomass are common, although seldom the focus of biodiversity-ecosystem functioning studies. We use natural, small-scale patchiness in the density of two species of large bivalves with contrasting feeding modes (the suspension-feeding Austrovenus stutchburyi and deposit-feeding Macomona liliana) to examine their influence on the uptake of nitrogen from macroalgae detritus (i.e. measure of ecosystem function and food web efficiency) by other infauna in a 10-d laboratory isotope-tracer experiment. We predicted that densities of these key bivalve species and functional group diversity (calculated as Shannons H, a density-independent measure of community composition) of the intact infaunal community will be critical factors explaining variance in macroalgal per capita uptake rates by the community members and hence determine total uptake by the community. Results show that only two species, M. liliana and a large orbiniid polychaete (Scoloplos cylindrifer) dominated macroalgal nitrogen taken up by the whole community due to their large biomass. However, their densities were mostly not important or negatively influenced per capita uptake by other species. Instead, the density of a head-down deposit-feeder (the capitellid Heteromastus filiformis), scavengers (mainly nemertines and nereids) and species and functional group diversity, best explained per capita uptake rates in community members. Our results demonstrate the importance of species identity, density and large body size for ecosystem functioning and highlight the complex interactions underlying loss of ecological functions with declining biodiversity and compositional changes.

  • 339.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reutgard, Martin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Isotopic niche reflects stress-induced variability in physiological status2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 2, article id 171398Article in journal (Refereed)
    Abstract [en]

    The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpreted as alterations in isotopic niche. This hypothesis was tested by inducing physiological stress in the deposit-feeding amphipod Monoporeia affinis exposed to either different feeding regimes or contaminated sediments. In the amphipods, we measured body condition indices or reproductive output to assess growth status and delta C-13 and delta N-15 values to derive isotope niche metrics. As hypothesized, greater isotopic niche estimates were derived for the stressed animals compared to the control groups. Moreover, the delta N-15 values were influenced by body size, reproductive status and parasite infestations, while delta C-13 values were influenced by body size, oxygen conditions and survival. Using regression analysis with isotope composition and growth variables as predictors, we were able to discriminate between the amphipods exposed to nutritionally or chemically stressful conditions and those in the control groups. Thus, interpretation of isotopic niche can be confounded by natural or anthropogenic stressors that may induce an apparent change in isotopic niche. These findings stress the importance of including measures of growth and health status when evaluating stable isotope data in food web studies.

  • 340.
    Karlsson, Emma
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Compositional clues to sources and sinks of terrestrial organic matter transported to the Eurasian Arctic shelf2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The amount of organic carbon (OC) present in Siberian Arctic permafrost soils is estimated at twice the amount of carbon currently in the atmosphere. The shelf seas of the Arctic Ocean receive large amounts of this terrestrial OC from Eurasian Arctic rivers and from coastal erosion. Degradation of this land-derived material in the sea would result in the production of dissolved carbon dioxide and may then add to the atmospheric carbon dioxide reservoir. Observations from the Siberian Arctic suggest that transfer of carbon from land to the marine environment is accelerating. However, it is not clear how much of the transported OC is degraded and oxidized, nor how much is removed from the active carbon cycle by burial in marine sediment.

    Using bulk geochemical parameters, total OC, d13C and D14C isotope composition, and specific molecular markers of plant wax lipids and lignin phenols, the abundance and composition of OC was determined in both dissolved and particulate carrier phases: the colloidal OC (COC; part of the dissolved OC), particulate OC (POC), and sedimentary OC (SOC). Statistical modelling was used to quantify the relative contribution of OC sources to these phases. Terrestrial OC is derived from the seasonally thawing top layer of permafrost soil (topsoil OC) and frozen OC derived from beneath the active layer eroded at the coast, commonly identified as yedoma ice complex deposit OC (yedoma ICD-OC). These carbon pools are transported differently in the aquatic conduits. Topsoil OC was found in young DOC and POC, in the river water, and the shelf water column, suggesting long-distance transport of this fraction. The yedoma ICD-OC was found as old particulate OC that settles out rapidly to the underlying sediment and is laterally transported across the shelf, likely dispersed by bottom nepheloid layer transport or via ice rafting.

    These two modes of OC transport resulted in different degradation states of topsoil OC and yedoma ICD-OC. Terrestrial CuO oxidation derived biomarkers indicated a highly degraded component in the COC. In contrast, the terrestrial component of the SOC was much less degraded. In line with earlier suggestions the mineral component in yedoma ICD functions as weight and surface protection of the associated OC, which led to burial in the sediment, and limited OC degradation. The degradability of the terrestrial OC in shelf sediment was also addressed in direct incubation studies. Molecular markers indicate marine OC (from primary production) was more readily degraded than terrestrial OC. Degradation was also faster in sediment from the East Siberian Sea, where the marine contribution was higher compared to the Laptev Sea. Although terrestrial carbon in the sediment was degraded slower, the terrestrial component also contributed to carbon dioxide formation in the incubations of marine sediment.

    These results contribute to our understanding of the marine fate of land-derived OC from the Siberian Arctic. The mobilization of topsoil OC is expected to grow in magnitude with climate warming and associated active layer deepening. This translocated topsoil OC component was found to be highly degraded, which suggests degradation during transport and a possible contribution to atmospheric carbon dioxide. Similarly, the yedoma ICD-OC (and or old mineral soil carbon) may become a stronger source with accelerated warming, but slow degradation may limit its impact on active carbon cycling in the Siberian Shelf Seas.

  • 341.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Alling, Vanja
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    van Dongen, Bart
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Manchester, UK.
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Contrasting sources of dissolved and particulate organic matter along 62N-72N in the Siberian-Arctic Lena RiverManuscript (preprint) (Other academic)
    Abstract [en]

    The Lena River transports large amounts of sediment and dissolved organic matter to the shallow Laptev Sea, where it may be subject to degradation and potential release of OC. We studied organic matter collected in summer 2008, along a 1450 km section of the Lena River, from near Yakutsk at 62°N to the deltaic region at 72°N, to better understand potential in-river processing of the terrestrial particulate and dissolved fractions in the river surface water.

    Carbon isotopes (δ13C and Δ14C) and plant wax lipid markers combine to reveal two distinct OC pools with different behavior in the river. The molar OC/TN ratios for POC were low (6-13) which suggests contribution from (freshwater) plankton, but most of the POC was of old age (770-4500 14C years) which rather suggests a pre-aged origin - perhaps from erosion of riverbank permafrost material. Much in contrast, COC was young (20-440 14C years) and displayed a high OC/TN composition (23-56) with a steady δ13C signal along the river course (-26.7 to -27.7). There was an apparent absence of ice complex deposit permafrost (mineral soil/yedoma OC) in the COC fraction, and only small contributions to POC. The COC signal suggest contribution from contemporary plant detritus/surface soil OC. It seems as if pre-aged permafrost OC, potentially from riverbank erosion, partitions into the particulate pool and almost not at all to the DOC/COC pool.

    Degradation markers indicate a highly degraded COC lipid pool and a less degraded POC - the n-alkane carbon preference index (CPI, C24-C34) was 1.0-1.3 for COC and 1.2-4.9 (on average 3.3) for POC.

    Taken together DOC/COC and POC have clearly different terrestrial sources and different fates on its way to the shelf waters. Previously freeze-locked old permafrost OC remobilizes into the Lena River in particulate form which (at least temporarily) escapes degradation as it follows the river course seawards in a less degraded state.

  • 342.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gelting, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Institute of Marine Sciences, Italy.
    van Dongen, Bart
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Orjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin2016In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 30, no 6, p. 898-919Article in journal (Refereed)
    Abstract [en]

    Thawing Arctic permafrost causes massive fluvial and erosional releases of dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and degradation of remobilized terrestrial carbon may affect large-scale carbon cycling, by comparing molecular and dual-isotope composition of waterborne high molecular weight DOC (>1kD, aka colloidal OC), POC, and sedimentary OC (SOC) across the East Siberian Arctic Shelves. Lignin phenol fingerprints demonstrate a longitudinal trend in relative contribution of terrestrial sources to coastal OC. Wax lipids and cutins were not detected in colloidal organic carbon (COC), in contrast to POC and SOC, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases. The C-14 signal suggests overwhelmingly contemporary sources for COC, while POC and SOC are dominated by old C from Ice Complex Deposit (ICD) permafrost. Monte Carlo source apportionment (C-13, C-14) constrained that COC was dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution ICD and other older permafrost stocks (9%). This distribution is likely a result of inherent compositional matrix differences, possibly driven by organomineral associations. Modern OC found suspended in the surface water may be more exposed to degradation, in contrast to older OC that preferentially settles to the seafloor where it may be degraded on a longer timescale. The different sources which partition into DOC, POC, and SOC appear to have vastly different fates along the Eurasian Arctic coastal margin and may possibly respond on different timescales to climate change.

  • 343.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gelting, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    van Dongen, Bart
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Different sources and degradation state of dissolved, particulate and sedimentary organic matter along the Eurasian Arctic coastal marginManuscript (preprint) (Other academic)
    Abstract [en]

    Thawing of permafrost in the Eurasian Arctic causes massive fluvial and erosional releases of both dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and extent of degradation of remobilized terrestrial carbon pools imprint on major recipient carbon pools and thereby affect large-scale carbon cycling.  The molecular and dual-isotope composition is compared with source end-member composition in waterborne high-molecular weight DOC (>1kD, a.k.a. colloidal OC), POC and in sedimentary OC (SOC) along coastal Kara, Laptev and East Siberian Seas.

    The lignin phenol fingerprint demonstrates a clear geospatial trend in the relative contribution of different terrestrial sources to coastal OC in going from the west to the east.  The wax lipids and cutins were much less abundant in the COC compared to in the POC and SOC compartment, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases.  The Δ14C signal suggests that the COC is overwhelmingly derived from contemporary carbon sources. Furthermore, degradation proxies based on terrestrial lignin phenol biomarkers suggest a highly degraded COC composition. Monte Carlo based source apportionment simulations of the δ13C/Δ14C composition constrained that the COC is dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution from Ice Complex Deposit (ICD) and other older stocks of permafrost carbon (9%). This contrasts starkly to the POC and especially the SOC compartment, which are dominated by old C from ICD-OC permafrost.

    These results combine with other recent studies to suggest a pattern along the East Siberian Arctic margin of SOC being constantly older yet less degraded than water column POC. This study also extends this perspective spatially along the Eurasian Arctic seaboard and also to the large COC (HMW DOC) pool, which is even younger yet even more degraded than the POC. An implication is that DOC and POC pools need to be treated separately in assessments of effects on the large-scale carbon cycle (and climate feedback) of old carbon released from thawing permafrost to aquatic receptors across the Eurasian Arctic coast. 

  • 344.
    Karlsson, Emma S.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bruchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Charkin, A.
    Dudarev, O.
    Semiletov, I.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Contrasting regimes for organic matter degradation in the East Siberian Sea and the Laptev Sea assessed through microbial incubations and molecular markers2015In: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 170, p. 11-22Article in journal (Refereed)
    Abstract [en]

    Compositional studies of organic matter on the East Siberian Arctic Shelf (ESAS) suggest that different terrestrial carbon pools have different propensities for transport and/or degradation. The current study combined laboratory-based microbial degradation experiments with earlier published degradation-diagnostic composition of several classes of terrestrial biomarkers on the same sediments to investigate differences and driving forces of terrestrial organic matter (TerrOM) degradation in two biogeochemically-contrasting regimes of the ESAS. The incubation-based anaerobic degradation rates were consistently higher (by average factor of 6) in the East Siberian Sea Kolyma Paleoriver Channel (ESS-KPC) (15 mu mol CO2 g OC-1 day(-1)) compared to the Laptev Sea Buor-Khaya Bay (LS-BKB) (2.4 mu mol CO2 g OC-1 day(-1)). The reported molecular markers show similarities between the terrestrial carbon pools in the two systems, but impose contrasting degradation regimes in combination with the incubation results. For the LS-BKB, there was a strong relationship between the degradation rates and the three lignin phenol-based degradation proxies (r(2) = 0.93-0.96, p < 0.01, linear regression) and two wax lipid-based degradation proxies (r(2) = 0.71 and 0.66, p < 0.05, linear regression). In contrast, for the ESS-KPC system, there was no relationship between incubation-based degradation rates and molecular marker-based degradation status of TerrOM. A principal component analysis indicated that short-chain fatty acids and dicarboxylic acids from CuO oxidation are mainly of terrestrial origin in the LS-BKB, but mainly of marine origin in the ESS-KPC. Hence, the microbial degradation in the western (LS-BKB) system appears to be fueled by TerrOM whereas the eastern (ESS-KPC) system degradation appears to be driven by MarOM. By combining molecular fingerprinting of TerrOM degradation state with laboratory-based degradation studies on the same ESAS sediments, a picture evolves of two distinctly different modes of TerrOM degradation in different parts of the ESAS system.

  • 345.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quaranta, Alessandro
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Glycosylation patterns of selected proteins in individual serum and cerebrospinal fluid samples2017In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 145, p. 431-439Article in journal (Refereed)
    Abstract [en]

    A method we previously developed has been applied to the determination of the glycosylation pattern of specific proteins in biological samples. Six proteins (alpha-1-anthrypsin, transferrin, haptoglobin, Cl inhibitor, alpha-1 acid glycoprotein, and immunoglobulin G) were studied in serum samples from five individuals and cerebrospinal fluid (CSF) samples from three individuals, to investigate the expected normal distribution of glycosylation patterns and to assess whether this methodology can be used to discriminate between samples from different individuals. For serum samples, the differences were shown to be small, while much larger differences were found for the CSF samples, with a greater number of glycoforms present. This can be linked to the occurrence of differential glycosylation in proteins expressed in the brain compared with proteins expressed elsewhere in the body. The developed method could distinguish differences in the glycosylation pattern of specific proteins in the individual samples, which was not reflected in the glycan content of total CSF. This is the first time that the glycoforms of several of these proteins have been investigated in CSF.

  • 346.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Samuelsson, Kristin
    Simonsson, Carl
    Stenfeldt, Anna-Lena
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jonsson, Charlotte
    Karlberg, Ann-Therese
    The Fate of a Hapten - From the Skin to Modification of Macrophage Migration Inhibitory Factor (MIF) in Lymph Nodes2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 2895Article in journal (Refereed)
    Abstract [en]

    Skin (contact) allergy, the most prevalent form of immunotoxicity in humans, is caused by low molecular weight chemicals (haptens) that penetrate stratum corneum and modify endogenous proteins. The fate of haptens after cutaneous absorption, especially what protein(s) they react with, is largely unknown. In this study the fluorescent hapten tetramethylrhodamine isothiocyanate (TRITC) was used to identify hapten-protein conjugates in the local lymph nodes after topical application, as they play a key role in activation of the adaptive immune system. TRITC interacted with dendritic cells but also with T and B cells in the lymph nodes as shown by flow cytometry. Identification of the most abundant TRITC-modified protein in lymph nodes by tandem mass spectrometry revealed TRITC-modification of the N-terminal proline of macrophage migration inhibitory factor (MIF) - an evolutionary well-conserved protein involved in cell-mediated immunity and inflammation. This is the first time a hapten-modified protein has been identified in lymph nodes after topical administration of the hapten. Most haptens are electrophiles and can therefore modify the N-terminal proline of MIF, which has an unusually reactive amino group under physiological conditions; thus, modification of MIF by haptens may have an immunomodulating role in contact allergy as well as in other immunotoxicity reactions.

  • 347. Karlsson, Oskar
    et al.
    Jiang, Liying
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ersson, Lisa
    Malmström, Tim
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Brittebo, Eva B.
    Environmental neurotoxin interaction with proteins: Dose-dependent increase of free and protein-associated BMAA (beta-N-methylamino-L-alanine) in neonatal rat brain2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 15570Article in journal (Refereed)
    Abstract [en]

    beta-Methylamino-L-alanine (BMAA) is implicated in the aetiology of neurodegenerative disorders. Neonatal exposure to BMAA induces cognitive impairments and progressive neurodegenerative changes including intracellular fibril formation in the hippocampus of adult rats. It is unclear why the neonatal hippocampus is especially vulnerable and the critical cellular perturbations preceding BMAA-induced toxicity remains to be elucidated. The aim of this study was to compare the level of free and protein-associated BMAA in neonatal rat brain and peripheral tissues after different exposures to BMAA. Ultra-high performance liquid chromatography-tandem mass spectrometry analysis revealed that BMAA passed the neonatal blood-brain barrier and was distributed to all studied brain areas. BMAA was also associated to proteins in the brain, especially in the hippocampus. The level in the brain was, however, considerably lower compared to the liver that is not a target organ for BMAA. In contrast to the liver there was a significantly increased level of protein-association of BMAA in the hippocampus and other brain areas following repeated administration suggesting that the degradation of BMAA-associated proteins may be lower in neonatal brain than in the liver. Additional evidence is needed in support of a role for protein misincorporation in the neonatal hippocampus for long-term effects of BMAA.

  • 348. Kase, Robert
    et al.
    Korkaric, Muris
    Werner, Inge
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Criteria for Reporting and Evaluating ecotoxicity Data (CRED): comparison and perception of the Klimisch and CRED methods for evaluating reliability and relevance of ecotoxicity studies2016In: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 28, article id 7Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The regulatory evaluation of ecotoxicity studies for environmental risk and/or hazard assessment of chemicals is often performed using the method established by Klimisch and colleagues in 1997. The method was, at that time, an important step toward improved evaluation of study reliability, but lately it has been criticized for lack of detail and guidance, and for not ensuring sufficient consistency among risk assessors.

    RESULTS: A new evaluation method was thus developed: Criteria for Reporting and Evaluating ecotoxicity Data (CRED). The CRED evaluation method aims at strengthening consistency and transparency of hazard and risk assessment of chemicals by providing criteria and guidance for reliability and relevance evaluation of aquatic ecotoxicity studies. A two-phased ring test was conducted to compare and characterize the differences between the CRED and Klimisch evaluation methods. A total of 75 risk assessors from 12 countries participated. Results show that the CRED evaluation method provides a more detailed and transparent evaluation of reliability and relevance than the Klimisch method. Ring test participants perceived it to be less dependent on expert judgement, more accurate and consistent, and practical regarding the use of criteria and time needed for performing an evaluation.

    CONCLUSIONS: We conclude that the CRED evaluation method is a suitable replacement for the Klimisch method, and that its use may contribute to an improved harmonization of hazard and risk assessments of chemicals across different regulatory frameworks.

  • 349. Kerré, B.
    et al.
    Bravo, C. T.
    Leifeld, J.
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Smolders, E.
    Historical soil amendment with charcoal increases sequestration of non-charcoal carbon: a comparison among methods of black carbon quantification2016In: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 67, no 3, p. 324-331Article in journal (Refereed)
    Abstract [en]

    We have shown previously that soil with historical (>150 years) applications of charcoal had larger recent (C4-maize derived) carbon content than adjacent soil; however, we could not determine whether there was an effect on older, C3-plant-derived, soil organic carbon (SOC). Therefore, we assessed the effect of historical additions of charcoal on the sequestration of recent and older SOC with a combination of delta C-13 analysis and different quantification techniques for black carbon (BC): dichromate oxidation (Cr2O7), chemo-thermal oxidation (CTO-285) and differential scanning calorimetry (DSC). Topsoils cropped with maize (Zea mays) under former charcoal production sites (N = 12) were identified in the field as black spots and had a larger (3.5%, P < 0.05) percentage of organic carbon (OC) contents than adjacent soil outside these spots (2.0%). The charcoal content varied with the detection technique used as follows: CTO-285 > DSC > Cr2O7. Black spots contained 1.6-1.7 times more (P < 0.05) maize-derived OC content than adjacent soil, irrespective of the BC quantification technique. The content of non-charcoal OC was 1.0-1.4 times larger in black spots than in adjacent soil, but differences were significant only for the Cr2O7 method. Soil physicochemical fractionation showed that at charcoal production sites more OC was recovered in the particulate organic matter and silt and clay fractions. The delta C-13 analysis suggested that additional maize-OC in black spots was in the physically more protected silt and clay fraction. Overall, this study shows that historical charcoal amendment in soil enhances the accumulation of recent maize-derived OC in a temperate climate without replacing the older C stocks.

  • 350.
    Keshavarzi, Neda
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Mashayekhy Rad, Farshid
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mace, Amber
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ansari, Farhan
    Akhtar, Farid
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Berglund, Lars
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Nanocellulose-Zeolite Composite Films for Odor Elimination2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 26, p. 14254-14262Article in journal (Refereed)
    Abstract [en]

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 mu m thick zeolite CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography mass spectroscopy (GC/MS) analysis showed that the CNF zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

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