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  • 1.
    Aasa, Jenny
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cancer Risk Assessment of Glycidol: Evaluation of a Multiplicative Risk Model for Genotoxic Compounds2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Humans are exposed to chemical compounds in everyday life, both from the environment and from endogenous processes. Some compounds constitute a risk for cancer development. One such compound is glycidol, which is genotoxic and an animal carcinogen. It is the model compound of this work, partly due to its presence in food. Glycidol, often together with 3-monochloropropane-1,2-diol (3-MCPD), occurs in the form of esters particularly in refined cooking oils, which are used in a variety of food products. The esters are hydrolyzed in the gastrointestinal tract to form glycidol (and 3-MCPD).

    The aim of the thesis has been to evaluate an approach for cancer risk estimation of genotoxic carcinogens based on a multiplicative (relative) risk model and genotoxic potency. Further, the aim was to estimate the cancer risk for exposure to glycidol via food. Measurement of the internal doses (concentration × time) of glycidol in the studied biological systems, including humans, has been crucial. Glycidol is electrophilic and forms adducts with nucleophilic sites in proteins and DNA. The doses of glycidol were quantified by mass spectrometry: in vivo from adduct levels to hemoglobin (Hb); in vitro from adducts to cob(I)alamin.

    The first part of the thesis concerns the genotoxic potency (genotoxic response per internal dose) of glycidol, measured in vitro by mutation studies and in vivo by micronuclei as a biomarker for genotoxicity (short-term studies in mice). The results were compared to that of ionizing radiation, used as a standard, to estimate the relative genotoxic potency of glycidol: 10 and 15 rad-equ./mMh from mutations and micronuclei, respectively. No induction of micronuclei was observed for the related compound 3-MCPD.

    Tumor incidence from published carcinogenicity studies of glycidol in mice and rats, together with the measured in vivo doses, was evaluated with the relative cancer risk model. A good agreement between predicted and observed tumor incidence was shown, and no significant difference of the obtained cancer risk coefficients (risk per dose) between mice (5.1 % per mMh) and rats (5.4 % per mMh) was observed. The overall results support that the relative risk coefficient (β) is independent of sex, tumor site, and species, and indicated that it can be transferred also to humans. The doubling dose, expressed as 1/β, is the dose that is required to double the background tumor incidence. The mean of the doubling doses from mice and rats (19 mMh) was assumed valid for risk estimation for humans. Transfer of β of glycidol to rad-equ. via its relative genotoxic potency showed a risk coefficient in agreement with the relative cancer risk coefficient of ionizing radiation.

    In the final work, the lifetime (70 years) in vivo doses of glycidol were calculated from measured Hb adduct levels in blood from 50 children and 12 adults, and compared to the doubling dose. A fivefold variation was observed in the in vivo doses. The estimated lifetime excess cancer risk from glycidol exceeds 1/1000. This is much higher than what is considered as an acceptable risk.

    To conclude, the multiplicative (relative) risk model together with relative genotoxic potency is promising to use in an approach for cancer risk estimation and in line with 3R (reduce-refine-replace) initiatives.

  • 2.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Abramsson-Zetterberg, Lilianne
    Carlsson, Henrik
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    The genotoxic potency of glycidol established from micronucleus frequency and hemoglobin adduct levels in mice2017In: Food and Chemical Toxicology, ISSN 0278-6915, E-ISSN 1873-6351, Vol. 100, p. 168-174Article in journal (Refereed)
    Abstract [en]

    Glycidol is a genotoxic animal carcinogen that has raised concern due to its presence in food, as glycidyl fatty acid esters. Here we investigated the genotoxicity of glycidol in BalbC mice (0-120 mg/kg) by monitoring the induction of micronuclei in peripheral blood as a marker of chromosomal damage. The scoring of the micronuclei was assessed by flow cytometry. In the treated mice, the internal dose of glycidol, expressed as area under the concentration-time curve, AUC (mol x L-1 x h; Mh), was measured by dihydroxypropyl adducts to hemoglobin (Hb). The study showed that glycidol induced linear dose dependent increases of Hb adducts (20 pmol/g Hb per mg/kg) and of micronuclei frequencies (12 parts per thousand per mMh). Compared to calculations based on administered dose, an improved dose-response relationship was observed when considering internal dose, achieved through the applied combination of sensitive techniques used for the scoring of micronuclei and AUC estimation of glycidol in the same mice. By comparing with earlier studies on micronuclei induction in mice exposed to ionizing radiation we estimated the radiation dose equivalent (rad-eq.) of glycidol to be ca 15 rad-eq./mMh.

  • 3.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Abramsson-Zetterberg, Lilianne
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. National Food Agency, Sweden.
    Measurement of micronuclei and internal dose in mice demonstrates that 3-monochloropropane-1,2-diol (3-MCPD) has no genotoxic potency in vivo2017In: Food and Chemical Toxicology, ISSN 0278-6915, E-ISSN 1873-6351, Vol. 109, p. 414-420Article in journal (Refereed)
    Abstract [en]

    In this study 3-monochloropropane-1,2-diol (3-MCPD), a compound that appears as contaminant in refined cooking oils, has been studied with regard to genotoxicity in vivo (mice) with simultaneous measurement of internal dose using state-of-the-art methodologies. Genotoxicity (chromosomal aberrations) was measured by flow cytometry with dual lasers as the frequency of micronuclei in erythrocytes in peripheral blood from BalbC mice intraperitoneally exposed to 3-MCPD (0, 50, 75, 100, 125 mg/kg). The internal doses of 3-MCPD in the mice were calculated from N-(2,3-dihydroxypropyl)-valine adducts to hemoglobin (Hb), quantified at very low levels by high-resolution mass spectrometry.

    Convincing evidence for absence of genotoxic potency in correlation to measured internal doses in the mice was demonstrated, despite relatively high administered doses of 3-MCPD. The results are discussed in relation to another food contaminant that is formed as ester in parallel to 3-MCPD esters in oil processing, i.e. glycidol, which has been studied previously by us in a similar experimental setup. Glycidol has been shown to be genotoxic, and in addition to have ca. 1000 times higher rate of adduct formation compared to that observed for 3-MCPD. The conclusion is that at simultaneous exposure to 3-MCPD and glycidol the concern about genotoxicity would be glycidol.

  • 4.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Granath, Fredrik
    Cancer risk estimation of glycidol based on rodent carcinogenicity studies, a multiplicative risk model and in vivo dosimetryManuscript (preprint) (Other academic)
    Abstract [en]

    Here we evaluate a multiplicative (relative) risk model for more reliable cancer risk estimations of genotoxic compounds. According to this model, cancer risk is proportional to background tumor incidence and to internal dose of the genotoxic compound. A relative risk coefficient is considered to be common across species, sex, and tumor sites. The model has previously been shown to be successfully applied to rodent carcinogenicity data for a few genotoxic compounds. The aim of the present study was to evaluate this risk model for glycidol, a common food contaminant. Tumor data from published glycidol carcinogenicity studies in mice and rats were evaluated with the model, using internal doses estimated from hemoglobin adduct measurements in blood of B6C3F1 mice and Sprague Dawley rats treated with glycidol in short-term exposure studies.

    The evaluation demonstrated that the relative risk model is valid for glycidol. A good agreement between predicted and observed tumor incidence was demonstrated in the animals, supporting a relative risk coefficient that is independent of species, sex, and tumor site. There was no significant difference of the risk coefficients between mice (5.1 % per mMh) and rats (7.1 % per mMh) when the internal doses of glycidol were considered. Altogether, this mechanism-based risk model gives a common and more reliable risk coefficient which could be extrapolated to humans via internal dose measurements, and by considering the background cancer incidence.

  • 5.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vare, Daniel
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Motwani, Hitesh V.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jenssen, Dag
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quantification of the mutagenic potency and repair of glycidol-induced DNA lesions2016In: Mutation research. Genetic toxicology and environmental mutagenesis, ISSN 1383-5718, E-ISSN 1879-3592, Vol. 805, p. 38-45Article in journal (Refereed)
    Abstract [en]

    Glycidol (Gly) is an electrophilic low-molecular weight epoxide that is classified by IARC as probably carcinogenic to humans. Humans might be exposed to Gly from food, e.g. refined vegetable oils, where Gly has been found as a food process contaminant. It is therefore important to investigate and quantify the genotoxicity of Gly as a primary step towards cancer risk assessment of the human exposure. Here, quantification of the mutagenic potency expressed per dose (AUC: area under the concentration time curve) of Gly has been performed in Chinese hamster ovary (CHO) cells, using the HPRT assay. The dose of Gly was estimated in the cell exposure medium by trapping Gly with a strong nucleophile, cob(I)alamin, to form stable cobalamin adducts for analysis by LC-MS/MS. Gly was stable in the exposure medium during the time for cell treatment, and thus the dose in vitro is the initial concentration x cell treatment time. Gly induced mutations in the hprt-gene at ante of 0.08 +/- 0:01 mutations/10(5) cells/mMh. Through comparison with the effect of ionizing radiation in the same system a relative mutagenic potency of 9.5 rad-eq./mMh was obtained, which could be used for comparison of genotoxicity of chemicals and between test systems and also in procedures for quantitative cancer risk assessment. Gly was shown to induce strand breaks, that were repaired by base excision repair. Furthermore, Gly-induced lesions, present during replication, were found to delay the replication fork elongation. From experiments with repair deficient cells, homologous recombination repair and the ERCC1-XPF complex were indicated to be recruited to support in the repair of the damage related to the stalled replication elongation. The type of DNA damage responsible for the mutagenic effect of Gly could not be concluded from the present study.

  • 6.
    Aasa, Jenny
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vryonidis, Efstathios
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Abramsson-Zetterberg, Lilianne
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Internal dose of glycidol in children and estimation of associated cancer riskManuscript (preprint) (Other academic)
    Abstract [en]

    Children are more susceptible to exposures to harmful compounds compared to adults. Monitoring of the actual exposures in vivo is important to enable risk mitigation actions. The general population, including children, is exposed to the carcinogen glycidol through food. A possible exposure source to glycidol is food containing refined cooking oils where it is present as a process-induced contaminant in the form of fatty acid esters.

    In the present study internal (in vivo) doses of the genotoxic and carcinogenic compound glycidol have been determined in a cohort of 50 children and in a reference group of 12 adults (non-smokers and smokers). The lifetime in vivo doses of glycidol have been calculated from the levels of the hemoglobin (Hb) adduct N-(2,3-dihydroxypropyl)-valine in blood samples from the subjects, demonstrating about a 5-fold variation between the children (71–322 µMh). This variation is likely due to different dietary habits and/or different genotypes/phenotypes of the enzymes involved in the detoxification of glycidol. Data from the adults indicate that the non-smoking subjects are exposed to about the same level as the children, whereas the smoking subjects have about double levels, likely due to the presence of glycidol in tobacco smoke. The estimated exposure to glycidol in the children is higher than those estimated by European Food Safety Authority.

    The calculated relative cancer risk increment due to glycidol exposure demonstrated an unacceptable risk for all subjects. The excess lifetime risk based on the estimated lifetime in vivo doses of glycidol exceeded 1/1000, which should be compared to a generally applied acceptable lifetime risk level of 1/100 000. A small contribution to the internal dose of glycidol from other precursors to the measured Hb adduct, and corresponding contribution to estimated risks from intake of glycidol from food cannot though be excluded.

  • 7. Abel, Sebastian
    et al.
    Nybom, Inna
    Maenpaa, Kimmo
    Hale, Sarah E.
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Norwegian Geotechnical Institute, Norway; Norwegian University of Life Sciences, Norway.
    Akkanen, Jarkko
    Mixing and capping techniques for activated carbon based sediment remediation Efficiency and adverse effects for Lumbriculus variegatus2017In: Water Research, ISSN 0043-1354, E-ISSN 1879-2448, Vol. 114, p. 104-112Article in journal (Refereed)
    Abstract [en]

    Activated carbon (AC) has been proven to be highly effective for the in-situ remediation of sediments contaminated with a wide range of hydrophobic organic contaminants (HOCs). However, adverse biological effects, especially to benthic organisms, can accompany this promising remediation potential. In this study, we compare both the remediation potential and the biological effects of several AC materials for two application methods: mixing with sediment (MIX) at doses of 0.1 and 1.0% based on sediment dw and thin layer capping (TLC) with 0.6 and 1.2 kg AC/m(2). Significant dose dependent reductions in PCB bioaccumulation in Lumbriculus variegatus of 35-93% in MIX treatments were observed. Contaminant uptake in TLC treatments was reduced by up to 78% and differences between the two applied doses were small. Correspondingly, significant adverse effects were observed for L. variegatus whenever AC was present in the sediment. The lowest application dose of 0.1% AC in the MIX system reduced L variegatus growth, and 1.0% AC led to a net loss of organism biomass. All TLC treatments let to a loss of biomass in the test organism. Furthermore, mortality was observed with 1.2 kg ACim(2) doses of pure AC for the TLC treatment. The addition of clay (Kaolinite) to the TLC treatments prevented mortality, but did not decrease the loss in biomass. While TLC treatments pose a less laborious alternative for AC amendments in the field, the results of this study show that it has lower remediation potential and could be more harmful to the benthic fauna.

  • 8.
    Acosta Navarro, Juan C.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ekman, Annica M. L.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Pausata, Francesco S. R.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Lewinschal, Anna
    Stockholm University, Faculty of Science, Department of Meteorology .
    Varma, Vidya
    Seland, Øyvind
    Gauss, Michael
    Iversen, Trond
    Kirkevåg, Alf
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hansson, Hans Christen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Future response of temperature and precipitation to reduced aerosol emissions as compared with increased greenhouse gas concentrations2017In: Journal of Climate, ISSN 0894-8755, E-ISSN 1520-0442, Vol. 30, no 3, p. 939-954Article in journal (Refereed)
    Abstract [en]

    Experiments with a climate model (NorESM1) were performed to isolate the effects of aerosol particles and greenhouse gases on surface temperature and precipitation in simulations of future climate. The simulations show that by 2025-2049, a reduction of aerosol emissions from fossil fuels following a maximum technically feasible reduction (MFR) scenario could lead to a global and Arctic warming of 0.26 K and 0.84 K, respectively; as compared with a simulation with fixed aerosol emissions at the level of 2005. If fossil fuel emissions of aerosols follow a current legislation emissions (CLE) scenario, the NorESM1 model simulations yield a non-significant change in global and Arctic average surface temperature as compared with aerosol emissions fixed at year 2005. The corresponding greenhouse gas effect following the RCP4.5 emission scenario leads to a global and Arctic warming of 0.35 K and 0.94 K, respectively.

    The model yields a marked annual average northward shift in the inter-tropical convergence zone with decreasing aerosol emissions and subsequent warming of the northern hemisphere. The shift is most pronounced in the MFR scenario but also visible in the CLE scenario. The modeled temperature response to a change in greenhouse gas concentrations is relatively symmetric between the hemispheres and there is no marked shift in the annual average position of the inter-tropical convergence zone. The strong reduction in aerosol emissions in MFR also leads to a net southward cross-hemispheric energy transport anomaly both in the atmosphere and ocean, and enhanced monsoon circulation in Southeast and East Asia causing an increase in precipitation over a large part of this region.

  • 9.
    Acosta Navarro, Juan Camilo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Anthropogenic influence on climate through changes in aerosol emissions from air pollution and land use change2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Particulate matter suspended in air (i.e. aerosol particles) exerts a substantial influence on the climate of our planet and is responsible for causing severe public health problems in many regions across the globe. Human activities have altered the natural and anthropogenic emissions of aerosol particles through direct emissions or indirectly by modifying natural sources. The climate effects of the latter have been largely overlooked. Humans have dramatically altered the land surface of the planet causing changes in natural aerosol emissions from vegetated areas. Regulation on anthropogenic and natural aerosol emissions have the potential to affect the climate on regional to global scales. Furthermore, the regional climate effects of aerosol particles could potentially be very different than the ones caused by other climate forcers (e.g. well mixed greenhouse gases). The main objective of this work was to investigate the climatic effects of land use and air pollution via aerosol changes.

    Using numerical model simulations it was found that land use changes in the past millennium have likely caused a positive radiative forcing via aerosol climate interactions. The forcing is an order of magnitude smaller and has an opposite sign than the radiative forcing caused by direct aerosol emissions changes from other human activities. The results also indicate that future reductions of fossil fuel aerosols via air quality regulations may lead to an additional warming of the planet by mid-21st century and could also cause an important Arctic amplification of the warming. In addition, the mean position of the intertropical convergence zone and the Asian monsoon appear to be sensitive to aerosol emission reductions from air quality regulations. For these reasons, climate mitigation policies should take into consideration aerosol air pollution, which has not received sufficient attention in the past.

  • 10.
    Acosta Navarro, Juan Camilo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Historical anthropogenic radiative forcing of changes in biogenic secondary organic aerosol2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human activities have lead to changes in the energy balance of the Earth and the global climate. Changes in atmospheric aerosols are the second largest contributor to climate change after greenhouse gases since 1750 A.D. Land-use practices and other environmental drivers have caused changes in the emission of biogenic volatile organic compounds (BVOCs) and secondary organic aerosol (SOA) well before 1750 A.D, possibly causing climate effects through aerosol-radiation and aerosol-cloud interactions. Two numerical emission models LPJ-GUESS and MEGAN were used to quantify the changes in aerosol forming BVOC emissions in the past millennium. A chemical transport model of the atmosphere (GEOS-Chem-TOMAS) was driven with those BVOC emissions to quantify the effects on radiation caused by millennial changes in SOA.

    The specific objectives of this licentiate thesis are: 1) to understand what drove the changes in aerosol-forming BVOC emissions (i.e. isoprene, monoterpenes and sesquiterpenes) and to quantify these changes; 2) to calculate for the first time the combined historical aerosol direct and aerosol-cloud albedo effects on radiation from changing BVOC emissions through SOA formation; 3) to investigate how important the biological climate feedback associated to BVOC emissions and SOA formation is from a global climate perspective.

    We find that global isoprene emissions decreased after 1800 A.D. by about 12% - 15%. This decrease was dominated by losses of natural vegetation, whereas monoterpene and sesquiterpene emissions increased by about 2% - 10%, driven mostly by rising surface air temperatures. From 1000 A.D. to 1800 A.D, isoprene, monoterpene and sesquiterpene emissions decline by 3% - 8% driven by both, natural vegetation losses, and the moderate global cooling between the medieval climate anomaly and the little ice age. The millennial reduction in BVOC emissions lead to a 0.5% to 2% reduction in climatically relevant aerosol particles (> 80 nm) and cause a direct radiative forcing between +0.02 W/m² and +0.07 W/m², and an indirect radiative forcing between -0.02 W/m² and +0.02 W/m². The suggested biological climate feedback seems to be too small to have observable consequences on the global climate in the recent past.

  • 11.
    Acosta Navarro, Juan Camilo
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Varma, Vidya
    Stockholm University, Faculty of Science, Department of Meteorology .
    Riipinen, Irina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Seland, O.
    Kirkevag, A.
    Struthers, Hamish
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Linköping University, Sweden.
    Iversen, T.
    Hansson, Hans-Christen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ekman, Annica M. L.
    Stockholm University, Faculty of Science, Department of Meteorology .
    Amplification of Arctic warming by past air pollution reductions in Europe2016In: Nature Geoscience, ISSN 1752-0894, E-ISSN 1752-0908, Vol. 9, no 4, p. 277-+Article in journal (Refereed)
    Abstract [en]

    The Arctic region is warming considerably faster than the rest of the globe(1), with important consequences for the ecosystems(2) and human exploration of the region(3). However, the reasons behind this Arctic amplification are not entirely clear(4). As a result of measures to enhance air quality, anthropogenic emissions of particulate matter and its precursors have drastically decreased in parts of the Northern Hemisphere over the past three decades(5). Here we present simulations with an Earth system model with comprehensive aerosol physics and chemistry that show that the sulfate aerosol reductions in Europe since 1980 can potentially explain a significant fraction of Arctic warming over that period. Specifically, the Arctic region receives an additional 0.3Wm(-2) of energy, and warms by 0.5 degrees C on annual average in simulations with declining European sulfur emissions in line with historical observations, compared with a model simulation with fixed European emissions at 1980 levels. Arctic warming is amplified mainly in fall and winter, but the warming is initiated in summer by an increase in incoming solar radiation as well as an enhanced poleward oceanic and atmospheric heat transport. The simulated summertime energy surplus reduces sea-ice cover, which leads to a transfer of heat from the Arctic Ocean to the atmosphere. We conclude that air quality regulations in the Northern Hemisphere, the ocean and atmospheric circulation, and Arctic climate are inherently linked.

  • 12.
    Ahlm, Lars
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yli-Juuti, T.
    Schobesberger, S.
    Praplan, A. P.
    Kim, J.
    Tikkanen, O. -P.
    Lawler, M. J.
    Smith, J. N.
    Trostl, J.
    Acosta Navarro, Juan Camilo
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Baltensperger, U.
    Bianchi, F.
    Donahue, N. M.
    Duplissy, J.
    Franchin, A.
    Jokinen, T.
    Keskinen, H.
    Kirkby, J.
    Kuerten, A.
    Laaksonen, A.
    Lehtipalo, K.
    Petaja, T.
    Riccobono, F.
    Rissanen, M. P.
    Rondo, L.
    Schallhart, S.
    Simon, M.
    Winkler, P. M.
    Worsnop, D. R.
    Virtanen, A.
    Riipinen, I.
    Modeling the thermodynamics and kinetics of sulfuric acid-dimethylamine-water nanoparticle growth in the CLOUD chamber2016In: Aerosol Science and Technology, ISSN 0278-6826, E-ISSN 1521-7388, Vol. 50, no 10, p. 1017-1032Article in journal (Refereed)
    Abstract [en]

    Dimethylamine (DMA) has a stabilizing effect on sulfuric acid (SA) clusters, and the SA and DMA molecules and clusters likely play important roles in both aerosol particle formation and growth in the atmosphere. We use the monodisperse particle growth model for acid-base chemistry in nanoparticle growth (MABNAG) together with direct and indirect observations from the CLOUD4 and CLOUD7 experiments in the cosmics leaving outdoor droplets (CLOUD) chamber at CERN to investigate the size and composition evolution of freshly formed particles consisting of SA, DMA, and water as they grow to 20nm in dry diameter. Hygroscopic growth factors are measured using a nano-hygroscopicity tandem differential mobility analyzer (nano-HTDMA), which combined with simulations of particle water uptake using the thermodynamic extended-aerosol inorganics model (E-AIM) constrain the chemical composition. MABNAG predicts a particle-phase ratio between DMA and SA molecules of 1.1-1.3 for a 2nm particle and DMA gas-phase mixing ratios between 3.5 and 80 pptv. These ratios agree well with observations by an atmospheric-pressure interface time-of-flight (APi-TOF) mass spectrometer. Simulations with MABNAG, direct observations of the composition of clusters <2nm, and indirect observations of the particle composition indicate that the acidity of the nucleated particles decreases as they grow from approximate to 1 to 20nm. However, MABNAG predicts less acidic particles than suggested by the indirect estimates at 10nm diameter using the nano-HTDMA measurements, and less acidic particles than observed by a thermal desorption chemical ionization mass spectrometer (TDCIMS) at 10-30nm. Possible explanations for these discrepancies are discussed.

  • 13.
    Ahmadi, Hamid
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bolinius, Dämien Johann
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jahnke, Annika
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mass transfer of hydrophobic organic chemicals between siliconesheets and through plant leaves and low-density polyethylene2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 164, p. 683-690Article in journal (Refereed)
    Abstract [en]

    Plant leaves play an important role in the fate of hydrophobic organic contaminants (HOCs) in theenvironment. Yet much remains unknown about the permeability of leaves by HOCs. In this pilot studywe measured (i) the kinetics of mass transfer of three polycyclic aromatic hydrocarbons (PAHs) and sixpolychlorinated biphenyls between a spiked and an unspiked sheet of polydimethylsiloxane (PDMS) indirect contact with each other for 24 h and (ii) kinetics of mass transfer of two PAHs through leaves andlow-density polyethylene (LDPE) in a passive dosing experiment by inserting these matrices between thetwo sheets of PDMS for 48 h. The kinetics of mass transfer of fluoranthene between PDMS sheets in directcontact were a factor of 12 slower than those reported in the literature. The kinetics of mass transfer offluorene and phenanthrene through leaves were within the range of those previously reported for 2,4-dichlorophenoxyacetic acid through isolated cuticles. Our results provide a proof-of-concept demon-stration that the passive dosing method applied in this study can be used to measure the mass transfercoefficients of organic chemicals through leaves. Key recommendations for future experiments are toload the PDMS at the highest feasible concentrations to avoid working at analyte levels close to the limitof detection, to keep the leaves moist and to minimize potential pathways for contamination of the PDMSsheets by exposure to laboratory air.

  • 14.
    Ahmadi, Mazaher
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Bu-Ali Sina University, Iran.
    Elmongy, Hatem
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Madrakian, Tayyebeh
    Abdel-Rehim, Mohamed
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nanomaterials as sorbents for sample preparation in bioanalysis: A review2017In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 958, p. 1-21Article, review/survey (Refereed)
    Abstract [en]

    In recent years, application of nanomaterials as sorbent has gained the attention of researchers in bioanalysis. Different nanomaterials have been utilized as the sorbent in extraction techniques such as solid phase extraction, dispersive solid phase extraction, magnetic solid phase extraction, microextraction by packed sorbent, solid phase microextraction, dispersive pt-solid phase extraction, and stir bar sorptive extraction. In the present review, different nanomaterials which have recently been utilized as sorbent for bioanalysis are classified into six main groups, namely metallic, metallic and mixed oxide, magnetic, carbonaceous, silicon, and polymer-based nanomaterials. Application of these nanomaterials in different extraction techniques for bioanalysis has been reviewed. This study shows that magnetic nanomaterials have gained significant attention owing to their magnetic separation ability. In addition, the present review shows that there is a lack in the application of nanomaterials for on-line analysis procedures, most probably due to some intrinsic properties of nanomaterials such as spontaneous agglomeration.

  • 15.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ahmed, Baram
    Aziz, Bakhtyar K.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Native and oxygenated polycyclic aromatic hydrocarbons in ambient air particulate matter from the city of Sulaimaniyah in Iraq2015In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 116, p. 44-50Article in journal (Refereed)
    Abstract [en]

    The concentrations of 43 polycyclic aromatic hydrocarbons (PAHs) and 4 oxygenated PAHs (OPAHs) are reported for the first time in particulate matter (PM10) sampled in the air of the city of Sulaimaniyah in Iraq. The total PAH concentration at the different sampling sites varied between 9.3 and 114 ng/m(3). The corresponding values of the human carcinogen benzotalpyrene were between 0.3 and 6.9 ng/m(3), with most samples exceeding the EU annual target value of 1 ng/m(3). The highly carcinogenic dibenzopyrene isomers dibenzo[a,l]pyrene, dibenzo[a,e]pyrene, dibenzo[a,i]pyrene and dibenzo[a,h]pyrene constituted 0.1-0.4% of the total PAH concentration. However, when scaling for relative cancer potencies using toxic equivalency factors, a benzo[a]pyrene equivalent concentration of dibenzo[a,l]pyrene equal to that of benzo[a]pyrene was obtained, indicating that the contribution of dibenzo[a,l]pyrene to the carcinogenicity of the PAHs could be similar to that of benzo[a]pyrene. A high correlation between the determined concentrations of the dibenzopyrene isomers and benzo[a]pyrene was found, which supported the use of benzo[a]pyrene as an indicator for the carcinogenicity of PAHs in ambient air. The total concentrations of the four OPAHs, 9,10-anthraquinone, 4H-cyclopenta[def]phenanthren-4-one, benzanthrone, and 7,12-benz[a]anthraquinone, varied between 0.6 and 8.1 ng/m(3), with 9,10-anthraquinone being the most abundant OPAH in all of the samples.

  • 16.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Emissions of particulate associated oxygenated and native polycyclic aromatic hydrocarbons from vehicles powered by ethanol/gasoline fuel blendsManuscript (preprint) (Other academic)
  • 17.
    Ahmed, Trifa M.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergvall, Christoffer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Emissions of particulate associated oxygenated and native polycyclic aromatic hydrocarbons from vehicles powered by ethanol/gasoline fuel blends2018In: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 214, p. 381-385Article in journal (Refereed)
    Abstract [en]

    Emission factors for oxygenated polycyclic aromatic hydrocarbons (OPAHs) and PAHs have been determined from two different fuel flexible light duty vehicles operated at -7 degrees C in the New European Driving Cycle (NEDC) and at +22 degrees C in the Artemis Driving Cycle (ADC). Three different gasoline/ethanol blends, commercially available in Sweden, were tested i.e., gasoline E5, with 5% v/v ethanol and ethanol fuel E85 with 85% v/v ethanol and winter time quality E70 with 70% v/v ethanol, respectively. The results showed greatly increased emissions of both OPAHs and PAHs at cold engine start conditions (-7 degrees C in the NEDC) compared to warm engine start (+ 22 degrees C in the ADC). For the OPAHs, higher average total emission factors were obtained when running on E85 compared to E5 at both cold 2.72 mu g/km vs 1.11 mu g/km and warm 0.19 mu g/km vs 0.11 mu g/km starting conditions with the highest emissions when using E70 at -7 degrees C 4.12 mu g/km. The same trend was found for the PAHs at cold engine start with higher average total emission factors when using ethanol fuel 71.5 mu g/km and 60.0 mu g/km for E70 and E85, respectively compared to gasoline E5 (20.2 mu g/km). Slightly higher average total PAH emissions were obtained when operating at + 22 degrees C with E5 compared to with E85 1.23 mu g/km vs 0.72 mu g/km.

  • 18. Al-Anati, Lauy
    et al.
    Viluksela, Matti
    Strid, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish Toxicology Sciences Research Center (Swetox), Sweden.
    Andersson, Patrik L.
    Stenius, Ulla
    Högberg, Johan
    Hydroxyl metabolite of PCB 180 induces DNA damage signaling and enhances the DNA damaging effect of benzo[a]pyrene2015In: Chemico-Biological Interactions, ISSN 0009-2797, E-ISSN 1872-7786, Vol. 239, p. 164-173Article in journal (Refereed)
    Abstract [en]

    Non-dioxin-like (NDL) polychlorinated biphenyls (PCBs) and their hydroxyl metabolites (OH-PCBs) are ubiquitous environmental contaminants in human tissues and blood. The toxicological impact of these metabolites is poorly understood. In this study rats were exposed to ultrapure PCB180 (10-1000 mg/kg bw) for 28 days and induction of genotoxic stress in liver was investigated. DNA damage signaling proteins (pChk1Ser317 and gamma H2AXSer319) were increased dose dependently in female rats. This increase was paralleled by increasing levels of the metabolite 3'-OH-PCB180. pChk1 was the most sensitive marker. In in vitro studies HepG2 cells were exposed to 1 mu M of PCB180 and 3'-OH-PCB180 or the positive control benzo[a]pyrene (BaP, 5 mu M). 3'-OH-PCB180, but not PCB180, induced CYP1A1 mRNA and gamma H2AX. CYP1A1 mRNA induction was seen at 1 h, and gamma H2AX at 3 h. The anti-oxidant N-Acetyl-L-Cysteine (NAC) completely prevented, and 17 beta-estradiol amplified the gamma H2AX induction by 3'-OH-PCB180. As 3'-OH-PCB180 induced CYP1A1, a major BaP-metabolizing and activating enzyme, interactions between 3'-OH-PCB180 and BaP was also studied. The metabolite amplified the DNA damage signaling response to BaP. In conclusion, metabolism of PCB180 to its hydroxyl metabolite and the subsequent induction of CYP1A1 seem important for DNA damage induced by PCB180 in vivo. Amplification of the response with estradiol may explain why DNA damage was only seen in female rats.

  • 19. Alastuey, Andres
    et al.
    Querol, Xavier
    Aas, Wenche
    Lucarelli, Franco
    Perez, Noemi
    Moreno, Teresa
    Cavalli, Fabrizia
    Areskoug, Hans
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Balan, Violeta
    Catrambone, Maria
    Ceburnis, Darius
    Cerro, Jose C.
    Conil, Sebastien
    Gevorgyan, Lusine
    Hueglin, Christoph
    Imre, Kornelia
    Jaffrezo, Jean-Luc
    Leeson, Sarah R.
    Mihalopoulos, Nikolaos
    Mitosinkova, Marta
    O'Dowd, Colin D.
    Pey, Jorge
    Putaud, Jean-Philippe
    Riffault, Veronique
    Ripoll, Anna
    Sciare, Jean
    Sellegri, Karine
    Spindler, Gerald
    Yttri, Karl Espen
    Geochemistry of PM10 over Europe during the EMEP intensive measurement periods in summer 2012 and winter 20132016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 10, p. 6107-6129Article in journal (Refereed)
    Abstract [en]

    The third intensive measurement period (IMP) organised by the European Monitoring and Evaluation Programme (EMEP) under the UNECE CLTRAP took place in summer 2012 and winter 2013, with PM10 filter samples concurrently collected at 20 (16 EMEP) regional background sites across Europe for subsequent analysis of their mineral dust content. All samples were analysed by the same or a comparable methodology. Higher PM10 mineral dust loadings were observed at most sites in summer (0.5-10aEuro-A mu gaEuro-m(-3)) compared to winter (0.2-2aEuro-A mu gaEuro-m(-3)), with the most elevated concentrations in the southern- and easternmost countries, accounting for 20-40aEuro-% of PM10. Saharan dust outbreaks were responsible for the high summer dust loadings at western and central European sites, whereas regional or local sources explained the elevated concentrations observed at eastern sites. The eastern Mediterranean sites experienced elevated levels due to African dust outbreaks during both summer and winter. The mineral dust composition varied more in winter than in summer, with a higher relative contribution of anthropogenic dust during the former period. A relatively high contribution of K from non-mineral and non-sea-salt sources, such as biomass burning, was evident in winter at some of the central and eastern European sites. The spatial distribution of some components and metals reveals the influence of specific anthropogenic sources on a regional scale: shipping emissions (V, Ni, and SO42-) in the Mediterranean region, metallurgy (Cr, Ni, and Mn) in central and eastern Europe, high temperature processes (As, Pb, and SO42-) in eastern countries, and traffic (Cu) at sites affected by emissions from nearby cities.

  • 20. Almén, Anna-Karin
    et al.
    Vehmaa, Anu
    Brutemark, Andreas
    Bach, Lennart
    Lischka, Silke
    Stuhr, Annegret
    Furuhagen, Sara
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Paul, Allanah
    Bermudez, J. Rafael
    Riebesell, Ulf
    Engström-Öst, Jonna
    Negligible effects of ocean acidification on Eurytemora affinis (Copepoda) offspring production2016In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 13, no 4, p. 1037-1048Article in journal (Refereed)
    Abstract [en]

    Ocean acidification is caused by increasing amounts of carbon dioxide dissolving in the oceans leading to lower seawater pH. We studied the effects of lowered pH on the calanoid copepod Eurytemora affinis during a mesocosm experiment conducted in a coastal area of the Baltic Sea. We measured copepod reproductive success as a function of pH, chlorophyll a concentration, diatom and dinoflagellate biomass, carbon to nitrogen (C : N) ratio of suspended particulate organic matter, as well as copepod fatty acid composition. The laboratory-based experiment was repeated four times during 4 consecutive weeks, with water and copepods sampled from pelagic mesocosms enriched with different CO2 concentrations. In addition, oxygen radical absorbance capacity (ORAC) of animals from the mesocosms was measured weekly to test whether the copepod's defence against oxidative stress was affected by pH. We found no effect of pH on offspring production. Phytoplankton biomass, as indicated by chlorophyll a concentration and dinoflagellate biomass, had a positive effect. The concentration of polyunsaturated fatty acids in the females was reflected in the eggs and had a positive effect on offspring production, whereas monounsaturated fatty acids of the females were reflected in their eggs but had no significant effect. ORAC was not affected by pH. From these experiments we conclude that E. affinis seems robust against direct exposure to ocean acidification on a physiological level, for the variables covered in the study. E. affinis may not have faced acute pH stress in the treatments as the species naturally face large pH fluctuations.

  • 21. Alves, Andreia
    et al.
    Giovanoulis, Georgios
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish Environmental Research Institute, Sweden.
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Erratico, Claudio
    Lucattini, Luisa
    Haug, Line S.
    Jacobs, Griet
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Leonards, Pim E. G.
    Covaci, Adrian
    Magner, Jorgen
    Voorspoels, Stefan
    Case Study on Screening Emerging Pollutants in Urine and Nails2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 7, p. 4046-4053Article in journal (Refereed)
    Abstract [en]

    Alternative plasticizers and flame retardants (FRs) have been introduced as replacements for banned or restricted chemicals, but much is still unknown about their metabolism and occurrence in humans. We identified the metabolites formed in vitro for four alternative plasticizers (acetyltributyl citrate (ATBC), bis(2-propylheptyl) phthalate (DPHP), bis(2-ethylhexyl) terephthalate (DEHTP), bis(2ethylhexyl) adipate (DEHA)), and one FR (2,2-bis (chloromethyl)-propane-1,3-diyltetrakis(2-chloroethyl) bisphosphate (V6)). Further, these compounds and their metabolites were investigated by LC/ESI-Orbitrap-MS in urine and finger nails collected from a Norwegian cohort. Primary and secondary ATBC metabolites had detection frequencies (% DF) in finger nails ranging from 46 to 95%. V6 was identified for the first time in finger nails, suggesting that this matrix may also indicate past exposure to FRs as well as alternative plasticizers. Two isomeric forms of DEHTP primary metabolite were highly detected in urine (97% DF) and identified in finger nails, while no DPHP metabolites were detected in vivo. Primary and secondary DEHA metabolites were identified in both matrices, and the relative proportion of the secondary metabolites was higher in urine than in finger nails; the opposite was observed for the primary metabolites. As many of the metabolites present in in vitro extracts were further identified in vivo in urine and finger nail samples, this suggests that in vitro assays can reliably mimic the in vivo processes. Finger nails may be a useful noninvasive matrix for human biomonitoring of specific organic contaminants, but further validation is needed.

  • 22. Anderson, Leif G.
    et al.
    Ek, Jörgen
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ericson, Ylva
    Humborg, Christoph
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Semiletov, Igor
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre.
    Ulfsbo, Adam
    Export of calcium carbonate corrosive waters from the East Siberian Sea2017In: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, no 7, p. 1811-1823Article in journal (Refereed)
    Abstract [en]

    The Siberian shelf seas are areas of extensive biogeochemical transformation of organic matter, both of marine and terrestrial origin. This in combination with brine production from sea ice formation results in a cold bottom water of relative high salinity and partial pressure of carbon dioxide (pCO(2)). Data from the SWERUS-C3 expedition compiled on the icebreaker Oden in July to September 2014 show the distribution of such waters at the outer shelf, as well as their export into the deep central Arctic basins. Very high pCO(2) water, up to similar to 1000 mu atm, was observed associated with high nutrients and low oxygen concentrations. Consequently, this water had low saturation state with respect to calcium carbonate down to less than 0.8 for calcite and 0.5 for aragonite. Waters undersaturated in aragonite were also observed in the surface in waters at equilibrium with atmospheric CO2; however, at these conditions the cause of undersaturation was low salinity from river runoff and/or sea ice melt. The calcium carbonate corrosive water was observed all along the continental margin and well out into the deep Makarov and Canada basins at a depth from about 50 m depth in the west to about 150 m in the east. These waters of low aragonite saturation state are traced in historic data to the Canada Basin and in the waters flowing out of the Arctic Ocean north of Greenland and in the western Fram Strait, thus potentially impacting the marine life in the North Atlantic Ocean.

  • 23.
    Andersson, Anastasia
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Johansson, Frank
    Sundbom, Marcus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ryman, Nils
    Stockholm University, Faculty of Science, Department of Zoology.
    Laikre, Linda
    Stockholm University, Faculty of Science, Department of Zoology.
    Lack of trophic polymorphism despite substantial genetic differentiation in sympatric brown trout (Salmo trutta) populations2017In: Ecology of Freshwater Fish, ISSN 0906-6691, E-ISSN 1600-0633, Vol. 26, no 4, p. 643-652Article in journal (Refereed)
    Abstract [en]

    Sympatric populations occur in many freshwater fish species; such populations are typically detected through morphological distinctions that are often coupled to food niche and genetic separations. In salmonids, trophic and genetically separate sympatric populations have been reported in landlocked Arctic char, whitefish and brown trout. In Arctic char and brown trout rare cases of sympatric, genetically distinct populations have been detected based on genetic data alone, with no apparent morphological differences, that is cryptic structuring. It remains unknown whether such cryptic, sympatric structuring can be coupled to food niche separation. Here, we perform an extensive screening for trophic divergence of two genetically divergent, seemingly cryptic, sympatric brown trout populations documented to remain in stable sympatry over several decades in two interconnected, tiny mountain lakes in a nature reserve in central Sweden. We investigate body shape, body length, gill raker metrics, breeding status and diet (stomach content analysis and stable isotopes) in these populations. We find small significant differences for body shape, body size and breeding status, and no evidence of food niche separation between these two populations. In contrast, fish in the two lakes differed in body shape, diet, and nitrogen and carbon isotope signatures despite no genetic difference between lakes. These genetically divergent populations apparently coexist using the same food resources and showing the same adaptive plasticity to the local food niches of the two separate lakes. Such observations have not been reported previously but may be more common than recognised as genetic screenings are necessary to detect the structures.

  • 24.
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    A Model for the Spectral Dependence of Aerosol Sunlight Absorption2017In: Acs Earth and Space Chemistry, ISSN 2472-3452, Vol. 1, no 9, p. 533-539Article in journal (Refereed)
    Abstract [en]

    Sunlight-absorbing aerosols, e.g., black and brown carbon (BC and BrC), have a potentially large, but highly uncertain contribution to climate warming. The spectral dependence of the aerosol absorption in the visible and near-UV regime is almost universally well-described with a heuristic power law, where the exponent is termed the absorption Angstrom exponent. However, the 2 underlying physicochemical causes for this relation are unknown. Here, a model is presented that predicts the emergence of the power law spectral dependence and unifies the absorption behavior of BC and BrC. Building on the theory of light absorption in amorphous materials, the interaction between multiple functional groups upon absorption is predicted to be a key feature for this broad spectral dependence. This aerosol amorphous absorption model is in agreement with recent empirical findings and provides a conceptual basis for the additional research needed to better constrain the optical properties of light-absorbing aerosols and their environmental impact.

  • 25.
    Andersson, August
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Deng, Junjun
    Du, Ke
    Zheng, Mei
    Yan, Caiqing
    Sköld, Martin
    Stockholm University, Faculty of Science, Department of Mathematics.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Regionally-Varying Combustion Sources of the January 2013 Severe Haze Events over Eastern China2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 4, p. 2038-2043Article in journal (Refereed)
    Abstract [en]

    Thick haze plagued northeastern China in January 2013, strongly affecting both regional climate and human respiratory health. Here, we present dual carbon isotope constrained (Delta C-14 and delta C-13) source apportionment for combustion-derived black carbon aerosol (BC) for three key hotspot regions (megacities): North China Plain (NCP, Beijing), the Yangtze River Delta (YRD, Shanghai), and the Pearl River Delta (PRD, Guangzhou) for January 2013. BC, here quantified as elemental carbon (EC), is one of the most health-detrimental components of PM2.5 and a strong climate warming agent. The results show that these severe haze events were equally affected (similar to 30%) by biomass combustion in all three regions, whereas the sources of the dominant fossil fuel component was dramatically different between north and south. In the NCP region, coal combustion accounted for 66% (46-74%, 95% C.I.) of the EC, whereas, in the YRD and PRD regions, liquid fossil fuel combustion (e.g., traffic) stood for 46% (18-66%) and 58% (38-68%), respectively. Taken together, these findings suggest the need for a regionally-specific description of BC sources in climate models and regionally-tailored mitigation to combat severe air pollution events in East Asia.

  • 26. Andriukonis, Eivydas
    et al.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kinetic N-15-isotope effects on algal growth2017In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, article id 44181Article in journal (Refereed)
    Abstract [en]

    Stable isotope labeling is a standard technique for tracing material transfer in molecular, ecological and biogeochemical studies. The main assumption in this approach is that the enrichment with a heavy isotope has no effect on the organism metabolism and growth, which is not consistent with current theoretical and empirical knowledge on kinetic isotope effects. Here, we demonstrate profound changes in growth dynamics of the green alga Raphidocelis subcapitata grown in N-15-enriched media. With increasing N-15 concentration (0.37 to 50 at%), the lag phase increased, whereas maximal growth rate and total yield decreased; moreover, there was a negative relationship between the growth and the lag phase across the treatments. The latter suggests that a trade-off between growth rate and the ability to adapt to the high N-15 environment may exist. Remarkably, the lag-phase response at 3.5 at% N-15 was the shortest and deviated from the overall trend, thus providing partial support to the recently proposed Isotopic Resonance hypothesis, which predicts that certain isotopic composition is particularly favorable for living organisms. These findings confirm the occurrence of KIE in isotopically enriched algae and underline the importance of considering these effects when using stable isotope labeling in field and experimental studies.

  • 27.
    Andrys, Rudolf
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Charles University Prague, Czech Republic .
    Zurita, Javier
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Zguna, Nadezda
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Verschueren, Klaas
    De Borggraeve, Wim M.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Improved detection of beta-N-methylamino-L-alanine using N-hydroxysuccinimide ester of N-butylnicotinic acid for the localization of BMAA in blue mussels (Mytilus edulis)2015In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, no 13, p. 3743-3750Article in journal (Refereed)
    Abstract [en]

    beta-N-Methylamino-l-alanine (BMAA) is an important non-protein amino acid linked to neurodegenerative diseases, specifically amyotrophic lateral sclerosis (ALS). Because it can be transferred and bioaccumulated higher up the food chain, it poses significant public health concerns; thus, improved detection methods are of prime importance for the identification and management of these toxins. Here, we report the successful use of N-hydroxysuccinimide ester of N-butylnicotinic acid (C-4-NA-NHS) for the efficient separation of BMAA from its isomers and higher sensitivity in detecting BMAA compared to the current method of choice using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization. Implementation of this efficient method allowed localization of BMAA in the non-visceral tissues of blue mussels, suggesting that more efficient depuration may be required to remove this toxin prior to consumption. This is a crucial method in establishing the absence or presence of the neurotoxic amino acid BMAA in food, environmental or biomedical samples.

  • 28. Andrén, Elinor
    et al.
    Telford, Richard J.
    Jonsson, Per
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reconstructing the history of eutrophication and quantifying total nitrogen reference conditions in Bothnian Sea coastal waters2017In: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 198, p. 320-328Article in journal (Refereed)
    Abstract [en]

    Reference total nitrogen (TN) concentrations for the Gardsfjarden estuary in the central Bothnian Sea, which receives discharge from an industrial point-source, have been estimated from diatom assemblages using a transfer function. Sedimentological and diatom evidence imply a good ecological status before 1920 with an assemblage dominated by benthic taxa indicating excellent water transparency, high diatom species richness and less organic sedimentation resulting in homogeneous well oxygenated sediments. A change in the diatom assemblage starts between 1920 and 1935 when the species richness declines and the proportion of planktic taxa increases. Increased organic carbon sedimentation after 1920 led to hypoxic bottom waters, and the preservation of laminae in the sediments. The trend in the reconstructed TN-values agrees with the history of the discharge from the mill, reaching maximum impact during the high discharge between 1945 and 1990. The background condition for TN in Gardsfjarden is 260-300 mu L-1, reconstructed until 1920.

  • 29.
    Areskoug, Hans
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Equivalence of PM10 Instruments ata Road Traffic Site: A Study in Stockholm Spring 20122015Report (Other academic)
  • 30.
    Avagyan, Rozanna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    From source to the environment: Strategies for identification and determination of hydroxylated polycyclic aromatic hydrocarbons in complex particulate matrices2017Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Adverse health effects have been linked to exposure to particulate matter, and wood combustion is considered as an important source of harmful particulate matter in the urban air and environment. Hydroxylated polycyclic aromatic hydrocarbons are a group of compounds with toxic, endocrine disrupting and carcinogenic properties. Sources of hydroxylated polycyclic aromatic hydrocarbons are different incomplete combustion processes, such as coal and wood combustion. They can also be formed by microbiological and/or photochemical degradation of polycyclic aromatic hydrocarbons in the environment.

    This thesis describes analytical strategies and methods that have been developed and used for screening, tentative identification and determination of hydroxylated polycyclic aromatic hydrocarbons in wood combustion and urban air particles. Conventional targeted analytical methods have been developed for compounds with available reference standards, while suspect and non-target screening strategies have been used for the identification of suspects and unknown compounds lacking reference standards. Each step of the developed analytical methods is described and discussed: the choice of the analytical strategy, sampling of the matrices, extraction, clean-up, instrumental analysis, data processing and validation of the methods.

    The influence of wood type (birch, spruce, pine and aspen) and burning conditions (nominal and high burn rate) on the hydroxylated polycyclic aromatic hydrocarbon emissions has been examined, showing that emissions from nominal burn rate combustion correspond on average to 14 % of the emissions from high burn rate combustion. It has been shown that spruce and pine have the highest emissions for nominal burn rate and high burn rate combustion, respectively.

    The composition of wood combustion particles has been examined and 32 suspect hydroxylated polycyclic aromatic hydrocarbons have been tentatively identified together with 20 other oxygen-containing small molecular weight compounds. Furthermore, the presence of hydroxylated polycyclic aromatic hydrocarbons in airborne particles from an urban background and a car tunnel has been investigated, and nine target and 11 suspect hydroxylated polycyclic aromatic hydrocarbons have been determined and tentatively identified, respectively.

    In summary, this thesis has shown that wood combustion is an important emission source of hydroxylated aromatic hydrocarbons and that the chemical composition of the emitted particles strongly depends on both burning conditions and wood type. Furthermore, the findings suggest that there might be other sources of these compounds in the urban environment than wood burning, such as the traffic. Thus, further investigations are required to fully understand the formation, sources and presence of hydroxylated polycyclic aromatic hydrocarbons in the atmosphere. The suitability of different analytical strategies and methods for identification and determination of hydroxylated polycyclic aromatic hydrocarbons is also discussed.

  • 31.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Luongo, Giovanna
    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.
    Östman, Conny
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Benzothiazole, benzotriazole, and their derivates in clothing textiles - a potential source of environmental pollutants and human exposure2015In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 22, no 8, p. 5842-5849Article in journal (Refereed)
    Abstract [en]

    Textiles play an important role in our daily life, and textile production is one of the oldest industries. In the manufacturing chain from natural and/or synthetic fibers to the final clothing products, the use of many different chemicals is ubiquitous. A lot of research has focused on chemicals in textile wastewater, but the knowledge of the actual content of harmful chemicals in clothes sold on the retail market is limited. In this paper, we have focused on eight benzothiazole and benzotriazole derivatives, compounds rated as high production volume chemicals. Twenty-six clothing samples of various textile materials and colors manufactured in 14 different countries were analyzed in textile clothing using liquid chromatography tandem mass spectrometry. Among the investigated textile products, 11 clothes were for babies, toddlers, and children. Eight of the 11 compounds included in the investigation were detected in the textiles. Benzothiazole was present in 23 of 26 investigated garments in concentrations ranging from 0.45 to 51 μg/g textile. The garment with the highest concentration of benzothiazole contained a total amount of 8.3 mg of the chemical. The third highest concentration of benzothiazole (22 μg/g) was detected in a baby body made from “organic cotton” equipped with the “Nordic Ecolabel” (“Svanenmärkt”). It was also found that concentrations of benzothiazoles in general were much higher than those for benzotriazoles. This study implicates that clothing textiles can be a possible route for human exposure to harmful chemicals by skin contact, as well as being a potential source of environmental pollutants via laundering and release to household wastewater.

  • 32.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nyström, Robin
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Determination of hydroxylated polycyclic aromatic hydrocarbons by HPLC-photoionization tandem mass spectrometry in wood smoke particles and soil samples2015In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, no 16, p. 4523-4534Article in journal (Refereed)
    Abstract [en]

    A simple and fast method for analysis of hydroxylated polycyclic aromatic hydrocarbons using pressurized liquid extraction and high performance liquid chromatography utilizing photoionization tandem mass spectrometry was developed. Simultaneous separation and determination of nine hydroxylated polycyclic aromatic hydrocarbons and two hydroxy biphenyls could be performed in negative mode with a run time of 12 min, including equilibration in 5 min. The calibration curves were in two concentration ranges; 1-50 ng/mL and 0.01-50 mu g/mL, with coefficients of correlation R (2) > 0.997. The limits of detection and method quantification limits were in the range of 9-56 pg and 5-38 ng/g, respectively. A two-level full factorial experimental design was used for screening of conditions with the highest impact on the extraction. The extraction procedure was automated and suitable for a large number of samples. The extraction recoveries ranged from 70 to 102 % and the matrix effects were between 92 and 104 %. The overall method was demonstrated on wood smoke particles and soil samples with good analytical performance, and five OH-PAHs were determined in the concentration range of 0.19-210 mu g/g. As far as we know, hydroxylated polycyclic aromatic hydrocarbons were determined in wood smoke and soil samples using photoionization mass spectrometry for the first time in this present study. Accordingly, this study shows that high performance liquid chromatography photoionization tandem mass spectrometry can be a good option for the determination of hydroxylated polycyclic aromatic hydrocarbons in complex environmental samples.

  • 33.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nyström, Robin
    Lindgren, Robert
    Boman, Christoffer
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Particulate hydroxy-PAH emissions from a residential wood log stove using different fuels and burning conditions2016In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 140, p. 1-9Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polycyclic aromatic hydrocarbons are oxidation products of polycyclic aromatic hydrocarbons, but have not been studied as extensively as polycyclic aromatic hydrocarbons. Several studies have however shown that hydroxylated polycyclic aromatic hydrocarbons have toxic and carcinogenic properties. They have been detected in air samples in semi urban areas and combustion is assumed to be the primary source of those compounds. To better understand the formation and occurrence of particulate hydroxylated polycyclic aromatic hydrocarbons from residential wood log stove combustion, 9 hydroxylated polycyclic aromatic hydrocarbons and 2 hydroxy biphenyls were quantified in particles generated from four different types of wood logs (birch, spruce, pine, aspen) and two different combustion conditions (nominal and high burn rate). A previously developed method utilizing liquid chromatography photo ionization tandem mass spectrometry and pressurized liquid extraction was used. Polycyclic aromatic hydrocarbons were analyzed along with hydroxylated polycyclic aromatic hydrocarbons. The hydroxylated polycyclic aromatic hydrocarbon emissions varied significantly across different wood types and burning conditions; the highest emissions for nominal burn rate were from spruce and for high burn rate from pine burning. Emissions from nominal burn rate corresponded on average to 15% of the emissions from high burn rate, with average emissions of 218 mu g/MJ(fuel) and 32.5 mu g/MJ(fuel) for high burn rate and nominal burn rate, respectively. Emissions of the measured hydroxylated polycyclic aromatic hydrocarbons corresponded on average to 28% of polycyclic aromatic hydrocarbons emissions. This study shows that wood combustion is a large emission source of hydroxylated polycyclic aromatic hydrocarbons and that not only combustion conditions, but also wood type influences the emissions of hydroxylated polycyclic aromatic hydrocarbons and polycyclic aromatic hydrocarbons. There are few studies that have determined hydroxylated polycyclic aromatic hydrocarbons in emissions from wood combustion, and it is therefore necessary to further investigate the formation, occurrence and distribution of these compounds as they are present in significant amounts in wood smoke particles.

  • 34.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Target and suspect screening of OH-PAHs in air particulate using liquid chromatography- orbitrap high resolution mass spectrometryManuscript (preprint) (Other academic)
  • 35.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Target and suspect screening of OH-PAHs in air particulates using liquid chromatography-orbitrap high resolution mass spectrometry2017In: Talanta: The International Journal of Pure and Applied Analytical Chemistry, ISSN 0039-9140, E-ISSN 1873-3573, Vol. 165, p. 702-708Article in journal (Refereed)
    Abstract [en]

    Up until now, the methods used for determination of hydroxylated polycyclic aromatic hydrocarbons in air particulate samples have been target methods, only determining compounds with available reference standards. In this present study, a combined target and suspect screening strategy for the analysis of hydroxylated polycyclic aromatic hydrocarbons was developed, utilizing liquid chromatography coupled to orbitrap high resolution mass spectrometry. The target screening included simultaneous determination of nine hydroxylated polycyclic aromatic hydrocarbons, while additional eight hydroxylated polycyclic aromatic hydrocarbon masses were screened for using the suspect screening. The target screening was validated with respect to linearity, limits of detection and quantification and matrix effects. The calibration curves ranged from 0.01 to 10 ng/mL, the method limits of detection and. quantification were in the rage of 0.001-0.018 pg/m(3) and 0.006-0.061 pg/m(3), respectively, while matrix effects ranged from 83% to 104%. For the suspect screening, a list with expected precursor ions created from suspect monoisotopic masses was used. The suspects were then identified by the accurate exact mass, with a mass accuracy threshold < 5 ppm, molecular formula, isotopic pattern, and mass spectra (fragments) and also semi-quantified in order to obtain information on their relative levels in different matrixes. The developed strategy was applied on five air particulate samples collected from an urban background and five samples from a car tunnel in Stockholm (Sweden). In total 20 hydroxylated polycyclic aromatic hydrocarbons were detected, of which nine compounds were determined using the target screening and 11 were tentatively identified and semi-quantified using the suspect screening strategy. The concentrations of the target compounds ranged from 20.7 to 96.9 pg/m(3), for most of the analytes the concentrations in particles from car tunnel were slightly higher than in urban air particles. The levels of most of the tentatively identified compounds were also slightly higher in particles from the car tunnel.

  • 36.
    Avagyan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Åberg, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Suspect screening of OH-PAHs and non-target screening of other organic compounds in wood smoke particles using HR-Orbitrap-MS2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 163, p. 313-321Article in journal (Refereed)
    Abstract [en]

    Wood combustion has been shown to contribute significantly to emissions of polycyclic aromatic hydrocarbons and hydroxylated polycyclic aromatic hydrocarbons, compounds with toxic and carcinogenic properties. However, only a small number of hydroxylated polycyclic aromatic hydrocarbons have been determined in particles from wood combustion, usually compounds with available reference standards. In this present study, suspect and non-target screening strategies were applied to characterize the wood smoke particles from four different wood types and two combustion conditions with respect to hydroxylated polycyclic aromatic hydrocarbons and other organic compounds. In the suspect screening, 32 peaks corresponding to 12 monohydroxylated masses were tentatively identified by elemental composition assignments and matching of isotopic pattern and fragments. More than one structure was suggested for most of the measured masses. Statistical analysis was performed on the non-target screening data in order to single out significant peaks having intensities that depend on the wood type and/or combustion condition. Significant peaks were found in both negative and positive ionization modes, with unique peaks for each wood type and combustion condition, as well as a combination of both factors. Furthermore, structural elucidation of some peaks was done by comparing the spectra in the samples with spectra found in the spectral databases. Six compounds were tentatively identified in positive ionization mode, and 19 in negative ionization mode. The results in this present study demonstrate that there are significant overall differences in the chemistry of wood smoke particles that depends on both the wood type and the combustion condition used.

  • 37.
    Avgayan, Rozanna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Target and suspect screening of OH-PAHs in air particulate using liquid chromatography- orbitrap high resolution mass spectrometry.Manuscript (preprint) (Other academic)
  • 38. Baars, Holger
    et al.
    Kanitz, Thomas
    Engelmann, Ronny
    Althausen, Dietrich
    Heese, Birgit
    Komppula, Mika
    Preissler, Jana
    Tesche, Matthias
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Meteorology .
    Ansmann, Albert
    Wandinger, Ulla
    Lim, Jae-Hyun
    Ahn, Joon Young
    Stachlewska, Iwona S.
    Amiridis, Vassilis
    Marinou, Eleni
    Seifert, Patric
    Hofer, Julian
    Skupin, Annett
    Schneider, Florian
    Bohlmann, Stephanie
    Foth, Andreas
    Bley, Sebastian
    Pfuller, Anne
    Giannakaki, Eleni
    Lihavainen, Heikki
    Viisanen, Yrjo
    Hooda, Rakesh Kumar
    Pereira, Sergio Nepomuceno
    Bortoli, Daniele
    Wagner, Frank
    Mattis, Ina
    Janicka, Lucja
    Markowicz, Krzysztof M.
    Achtert, Peggy
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Meteorology .
    Artaxo, Paulo
    Pauliquevis, Theotonio
    Souza, Rodrigo A. F.
    Sharma, Ved Prakesh
    van Zyl, Pieter Gideon
    Beukes, Johan Paul
    Sun, Junying
    Rohwer, Erich G.
    Deng, Ruru
    Mamouri, Rodanthi-Elisavet
    Zamorano, Felix
    An overview of the first decade of Polly(NET): an emerging network of automated Raman-polarization lidars for continuous aerosol profiling2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 8, p. 5111-5137Article in journal (Refereed)
    Abstract [en]

    A global vertically resolved aerosol data set covering more than 10 years of observations at more than 20 measurement sites distributed from 63 degrees N to 52 degrees S and 72 degrees W to 124 degrees E has been achieved within the Raman and polarization lidar network Polly(NET). This network consists of portable, remote-controlled multiwavelength-polarization-Raman lidars (Polly) for automated and continuous 24/7 observations of clouds and aerosols. Polly(NET) is an independent, voluntary, and scientific network. All Polly lidars feature a standardized instrument design with different capabilities ranging from single wavelength to multiwavelength systems, and now apply unified calibration, quality control, and data analysis. The observations are processed in near-real time without manual intervention, and are presented online at polly.tropos.de. The paper gives an overview of the observations on four continents and two research vessels obtained with eight Polly systems. The specific aerosol types at these locations (mineral dust, smoke, dust-smoke and other dusty mixtures, urban haze, and volcanic ash) are identified by their Angstrom exponent, lidar ratio, and depolarization ratio. The vertical aerosol distribution at the Polly(NET) locations is discussed on the basis of more than 55 000 automatically retrieved 30 min particle backscatter coefficient profiles at 532 nm as this operating wavelength is available for all Polly lidar systems. A seasonal analysis of measurements at selected sites revealed typical and extraordinary aerosol conditions as well as seasonal differences. These studies show the potential of Polly(NET) to support the establishment of a global aerosol climatology that covers the entire troposphere.

  • 39. Backman, John
    et al.
    Schmeisser, Lauren
    Virkkula, Aki
    Ogren, John A.
    Asmi, Eija
    Starkweather, Sandra
    Sharma, Sangeeta
    Eleftheriadis, Konstantinos
    Uttal, Taneil
    Jefferson, Anne
    Bergin, Michael
    Makshtas, Alexander
    Tunved, Peter
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Fiebig, Markus
    On Aethalometer measurement uncertainties and an instrument correction factor for the Arctic2017In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 10, no 12, p. 5039-5062Article in journal (Refereed)
    Abstract [en]

    Several types of filter-based instruments are used to estimate aerosol light absorption coefficients. Two significant results are presented based on Aethalometer measurements at six Arctic stations from 2012 to 2014. First, an alternative method of post-processing the Aethalometer data is presented, which reduces measurement noise and lowers the detection limit of the instrument more effectively than box-car averaging. The biggest benefit of this approach can be achieved if instrument drift is minimised. Moreover, by using an attenuation threshold criterion for data post-processing, the relative uncertainty from the electronic noise of the instrument is kept constant. This approach results in a time series with a variable collection time (Delta t) but with a constant relative uncertainty with regard to electronic noise in the instrument. An additional advantage of this method is that the detection limit of the instrument will be lowered at small aerosol concentrations at the expense of temporal resolution, whereas there is little to no loss in temporal resolution at high aerosol concentrations (>2.1-6.7Mm(-1) as measured by the Aethalometers). At high aerosol concentrations, minimising the detection limit of the instrument is less critical. Additionally, utilising co-located filter-based absorption photometers, a correction factor is presented for the Arctic that can be used in Aethalometer corrections available in literature. The correction factor of 3.45 was calculated for low-elevation Arctic stations. This correction factor harmonises Aethalometer attenuation coefficients with light absorption coefficients as measured by the co-located light absorption photometers. Using one correction factor for Arctic Aethalometers has the advantage that measurements between stations become more inter-comparable.

  • 40. Balducci, Catia
    et al.
    Green, David C.
    Romagnoli, Paola
    Perilli, Mattia
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. City of Stockholm, Sweden.
    Panteliadis, Pavlos
    Cecinato, Angelo
    Cocaine and cannabinoids in the atmosphere of Northern Europe cities, comparison with Southern Europe and wastewater analysis2016In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 97, p. 187-194Article, review/survey (Refereed)
    Abstract [en]

    This study reports the first investigation of atmospheric illicit drug concentrations in Northern Europe usingmeasurements of cocaine and cannabinoids in Amsterdam, London and Stockholm. Further, these measurements were compared to those made in Rome to explore the geographical and inter-city variability. Co-located measurements of atmospheric particulate mass and PAHs were used to help describe and interpret the illicit drug measurements with respect to atmospheric dispersion. Cocaine concentrations ranged from 0.03 to 0.14 ng/m(3) in Amsterdam, from 0.02 to 0.33 ng/m(3) in London and were below quantification limit (3pg/m(3)) in Stockholm. Cannabinol was the only cannabinoidmolecule detected in the three cities. During this campaign, London reported the highest concentrations of cocaine and meaningful differences were detected between the urban background and city centre London sites. Mean cocaine concentrations measured in Amsterdam during March 2011 were also compared with those measured simultaneously in eight Italian cities. The cocaine concentration inAmsterdamwas comparable to that measured at an urban background inMilan and at a densely populated site in Florence. Although correlating atmospheric concentrations directlywith drug prevalence is not possible using current data, links between concentrations of cocaine and estimates of abuse prevalence assessed by the more routinely usedwastewater analysiswere also examined. A statistically significant correlationwas found between the two sets of data (R-2= 0.66; p= 0.00131). Results confirmed that meteorology, population rate and habits of consumption influence the atmospheric concentrations of drugs. If these confounding factors were better controlled for, the techniques described here could became an easy and cost effective tool to index the impact of cocaine abuse in the area; especially where local hot spots need to be identified.

  • 41.
    Balk, Lennart
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hägerroth, Per-Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gustavsson, Hanna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sigg, Lisa
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Åkerman, Gun
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ruiz Munoz, Yolanda
    Honeyfield, Dale C.
    Tjärnlund, Ulla
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Oliveira, Kenneth
    Ström, Karin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    McCormick, Stephen D.
    Karlsson, Simon
    Ström, Marika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Karolinska Institutet, Sweden.
    van Manen, Mathijs
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Utrecht University, Germany.
    Berg, Anna-Lena
    Halldorsson, Halldor P.
    Strömquist, Jennie
    Collier, Tracy K.
    Börjeson, Hans
    Mörner, Torsten
    Hansson, Tomas
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Widespread episodic thiamine deficiency in Northern Hemisphere wildlife2016In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 6, article id 38821Article in journal (Refereed)
    Abstract [en]

    Many wildlife populations are declining at rates higher than can be explained by known threats to biodiversity. Recently, thiamine (vitamin B-1) deficiency has emerged as a possible contributing cause. Here, thiamine status was systematically investigated in three animal classes: bivalves, ray-finned fishes, and birds. Thiamine diphosphate is required as a cofactor in at least five life-sustaining enzymes that are required for basic cellular metabolism. Analysis of different phosphorylated forms of thiamine, as well as of activities and amount of holoenzyme and apoenzyme forms of thiaminedependent enzymes, revealed episodically occurring thiamine deficiency in all three animal classes. These biochemical effects were also linked to secondary effects on growth, condition, liver size, blood chemistry and composition, histopathology, swimming behaviour and endurance, parasite infestation, and reproduction. It is unlikely that the thiamine deficiency is caused by impaired phosphorylation within the cells. Rather, the results point towards insufficient amounts of thiamine in the food. By investigating a large geographic area, by extending the focus from lethal to sublethal thiamine deficiency, and by linking biochemical alterations to secondary effects, we demonstrate that the problem of thiamine deficiency is considerably more widespread and severe than previously reported.

  • 42. Bannan, Thomas J.
    et al.
    Booth, A. Murray
    Jones, Benjamin T.
    O'Meara, Simon
    Barley, Mark H.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Percival, Carl J.
    Topping, David
    Measured Saturation Vapor Pressures of Phenolic and Nitro-aromatic Compounds2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 7, p. 3922-3928Article in journal (Refereed)
    Abstract [en]

    Phenolic and nitro-aromatic compounds are extremely toxic components of atmospheric aerosol that are currently not well understood. In this Article, solid and subcooled-liquid-state saturation vapor pressures of phenolic and nitro-aromatic compounds are measured using Knudsen Effusion Mass Spectrometry (KEMS) over a range of temperatures (298-318 K). Vapor pressure estimation methods, assessed in this study, do not replicate the observed dependency on the relative positions of functional groups. With a few exceptions, the estimates are biased toward predicting saturation vapor pressures that are too high, by 5-6 orders of magnitude in some cases. Basic partitioning theory comparisons indicate that overestimation of vapor pressures in such cases would cause us to expect these compounds to be present in the gas state, whereas measurements in this study suggest these phenolic and nitro-aromatic will partition into the condensed state for a wide range of ambient conditions if absorptive partitioning plays a dominant role. While these techniques might have both structural and parametric uncertainties, the new data presented here should support studies trying to ascertain the role of nitrogen containing organics on aerosol growth and human health impacts.

  • 43. Baranizadeh, Elham
    et al.
    Murphy, Benjamin N.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Julin, Jan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Eastern Finland, Finland.
    Falahat, Saeed
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reddington, Carly L.
    Arola, Antti
    Ahlm, Lars
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mikkonen, Santtu
    Fountoukis, Christos
    Patoulias, David
    Minikin, Andreas
    Hamburger, Thomas
    Laaksonen, Ari
    Pandis, Spyros N.
    Vehkamäki, Hanna
    Lehtinen, Kari E. J.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Implementation of state-of-the-art ternary new-particle formation scheme to the regional chemical transport model PMCAMx-UF in Europe2016In: Geoscientific Model Development, ISSN 1991-959X, E-ISSN 1991-9603, Vol. 9, no 8, p. 2741-2754Article in journal (Refereed)
    Abstract [en]

    The particle formation scheme within PMCAMx-UF, a three-dimensional chemical transport model, was updated with particle formation rates for the ternary H2SO4-NH3-H2O pathway simulated by the Atmospheric Cluster Dynamics Code (ACDC) using quantum chemical input data. The model was applied over Europe for May 2008, during which the EUCAARI-LONGREX (European Aerosol Cloud Climate and Air Quality Interactions-Long-Range Experiment) campaign was carried out, providing aircraft vertical profiles of aerosol number concentrations. The updated model reproduces the observed number concentrations of particles larger than 4 nm within 1 order of magnitude throughout the atmospheric column. This agreement is encouraging considering the fact that no semi-empirical fitting was needed to obtain realistic particle formation rates. The cloud adjustment scheme for modifying the photolysis rate profiles within PMCAMx-UF was also updated with the TUV (Tropospheric Ultraviolet and Visible) radiative-transfer model. Results show that, although the effect of the new cloud adjustment scheme on total number concentrations is small, enhanced new-particle formation is predicted near cloudy regions. This is due to the enhanced radiation above and in the vicinity of the clouds, which in turn leads to higher production of sulfuric acid. The sensitivity of the results to including emissions from natural sources is also discussed.

  • 44. Batistuzzo, S.
    et al.
    Galvão, M. O.
    Duarte, E. S.
    Hoelzemann, J. J.
    Menezes Filho, J.
    Sadiktsis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Westerholm, Roger
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Dreij, K.
    PAH exposure and relationship between buccal micronucleus cytome assay and urinary 1-hydroxypyrene levels among cashew nut roasting workers2016In: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 258, p. S223-S224Article in journal (Refereed)
    Abstract [en]

    The present study conducted the first assessment of the occupational risk associated to artisanal cashew nut roasting by the use of exposure and effect biomarkers, as well as the characterization and dispersion analysis of the released particulate matter (PM). The PM concentrations in the exposed area were higher than in the non-exposed area. Furthermore, in the control area yielded a higher prevalence of coarse particles, while in the exposed area was observed fine particles. The morphological analysis showed a wide variety of particles. Biomass burning tracers K, Cl, S and Ca were the major inorganic compounds and polycyclic aromatic hydrocarbons (PAHs) with mutagenic and carcinogenic potential, such as benzo[a]pyrene, benzo[b]fluoranthene, benzo[a]anthracene, benzo[j]fluoranthene and indeno[1,2,3-c,d]pyrene were the most abundant PAHs. In addition, atmospheric modeling analysis suggest that these particles can reach regions higher than 40 kilometers. Occupational PAH exposure was confirmed by increases in 1-OHP levels in cashew nut workers. The frequencies of BMCyt biomarkers of genotoxic (micronuclei and nuclear bud) and cytotoxic (pyknosis, karyolysis, karyorrhexis and condensed chromatin) were higher in the exposed group (p < 0.0001) compared with the control group. The influence of factors such as age on the micronucleus was evidenced and a correlation between 1-OHP and MN was observed. It was the first study to found a correlation between these types of biomarkers. The uses of exposure and effect biomarkers were therefore efficient in assessing the occupational risk associated with artisanal cashew nut roasting and the high rates of PM2.5 are considered a potential contributor to this effect.

  • 45.
    Beer, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Permafrost Sub-grid Heterogeneity of Soil Properties Key for 3-D Soil Processes and Future Climate Projections2016In: Frontiers in Earth Science, ISSN 2296-6463, Vol. 4, article id UNSP 81Article in journal (Refereed)
    Abstract [en]

    There are massive carbon stocks stored in permafrost-affected soils due to the 3-D soil movement process called cryoturbation. For a reliable projection of the past, recent and future Arctic carbon balance, and hence climate, a reliable concept for representing cryoturbation in a land surface model (LSM) is required. The basis of the underlying transport processes is pedon-scale heterogeneity of soil hydrological and thermal properties as well as insulating layers, such as snow and vegetation. Today we still lack a concept of how to reliably represent pedon-scale properties and processes in a LSM. One possibility could be a statistical approach. This perspective paper demonstrates the importance of sub-grid heterogeneity in permafrost soils as a pre-requisite to implement any lateral transport parametrization. Representing such heterogeneity at the sub-pixel size of a LSM is the next logical step of model advancements. As a result of a theoretical experiment, heterogeneity of thermal and hydrological soil properties alone lead to a remarkable initial sub-grid range of subsoil temperature of 2C, and active-layer thickness of 150 cm in East Siberia. These results show the way forward in representing combined lateral and vertical transport of water and soil in LSMs.

  • 46.
    Beer, Christian
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Porada, Philipp
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ekici, Altug
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Bjerknes Centre for Climate Research, Norway.
    Brakebusch, Matthias
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Effects of short-term variability of meteorological variables on soil temperature in permafrost regions2018In: The Cryosphere, ISSN 1994-0416, E-ISSN 1994-0424, Vol. 12, no 2, p. 741-757Article in journal (Refereed)
    Abstract [en]

    Effects of the short-term temporal variability of meteorological variables on soil temperature in northern high-latitude regions have been investigated. For this, a process-oriented land surface model has been driven using an artificially manipulated climate dataset. Short-term climate variability mainly impacts snow depth, and the thermal diffusivity of lichens and bryophytes. These impacts of climate variability on insulating surface layers together substantially alter the heat exchange between atmosphere and soil. As a result, soil temperature is 0.1 to 0.8 degrees C higher when climate variability is reduced. Earth system models project warming of the Arctic region but also increasing variability of meteorological variables and more often extreme meteorological events. Therefore, our results show that projected future increases in permafrost temperature and active-layer thickness in response to climate change will be lower (i) when taking into account future changes in short-term variability of meteorological variables and (ii) when representing dynamic snow and lichen and bryophyte functions in land surface models.

  • 47.
    Bejgarn, Sofia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bogdal, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Institute for Chemical and Bioengineering, ETH Zurich, Switzerland.
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Toxicity of leachate from weathering plastics: An exploratory screening study with Nitocra spinipes2015In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 132, p. 114-119Article in journal (Refereed)
    Abstract [en]

    Between 60% and 80% of all marine litter is plastic. Leachate from plastics has previously been shown to cause acute toxicity in the freshwater species Daphnia magna. Here, we present an initial screening of the marine environmental hazard properties of leachates from weathering plastics to the marine harpacticoid copepod [Crustacea] Nitocra spinipes. Twenty-one plastic products made of different polymeric materials were leached and irradiated with artificial sunlight. Eight of the twenty-one plastics (38%) produced leachates that caused acute toxicity. Differences in toxicity were seen for different plastic products, and depending on the duration of irradiation. There was no consistent trend in how toxicity of leachate from plastics changed as a function of irradiation time. Leachate from four plastics became significantly more toxic after irradiation, two became significantly less toxic and two did not change significantly. Analysis of leachates from polyvinyl chloride (PVC) by liquid chromatography coupled to a full-scan high-resolution mass spectrometer showed that the leachates were a mixture of substances, but did not show evidence of degradation of the polymer backbone. This screening study demonstrates that leachates from different plastics differ in toxicity to N. spinipes and that the toxicity varies under simulated weathering.

  • 48.
    Bergman, Åke
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish toxicology sciences research center, Sweden; Karolinska Institutet, Sweden; Tongji University, China.
    Bignert, AndersQiu, YanlingStockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China.Yin, GeStockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Chemical Pollution - Challenges in the Yangtze River Delta, China: A 2017 Sino-Swedish Research Report2017Collection (editor) (Other academic)
    Abstract [en]

    Over time China became the globally most important manufacturer of chemicals and inherited the pollution problems with production and use of chemicals. The Yangtze River Delta is very much a central area for the chemical production and for manufacturing of a variety of chemical products, materials and goods. A science based cooperation between researchers from Tongji University, Stockholm University and the Swedish Museum of Natural History started to develop in the first decade of the present century. The cooperation was aimed to improve the understanding of chemical pollutants and their influence on wildlife and humans in the Yangtze River Delta area, to generate novel data and establish advanced chemical monitoring programs.

    Chemical Pollution — Challenges in the Yangtze River Delta is the first scientific report of the Chemstrres project, "Swedish-Chinese chemical pollution stress and risks research program in the Yangtze River Delta region". The project has been funded by the Swedish Research Council. This book covers the essentials of the natural, social, economic, and chemical environments of the Yangtze River Delta, as well as an up-to-date, introduction of the research activities and highlights within Chemstrres. The book is aimed to attract readers from all sectors of society; vivid graphics and diagrams can be found throughout the text. Both Chemstrres project and this book are expected to bring scientists and decision makers closer together, to enable science based management for improved human health and environmental prosperity. 

  • 49. Beronius, A.
    et al.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Making the most of expert judgment in hazard and risk assessment of chemicals2017In: Toxicology Research, ISSN 2045-452X, E-ISSN 2045-4538, Vol. 6, no 5, p. 571-577Article in journal (Refereed)
    Abstract [en]

    Evaluation of the reliability and relevance of toxicity and ecotoxicity studies is an integral step in the assessment of the hazards and risks of chemicals. This evaluation is inherently reliant on expert judgment, which often leads to differences between experts' conclusions regarding how individual studies can contribute to the body of evidence. The conclusions of regulatory assessment, such as establishing safe exposure levels for humans and the environment and calculations of margins of exposure, may have large consequences for which chemicals are permitted on the market and their allowed uses. It is therefore important that such assessments are based on all reliable and relevant scientific data, and that assessment principles and assumptions, such as expert judgment, are transparently applied. It is not possible nor desirable to completely eliminate expert judgment from the evaluation of (eco) toxicity studies. However, it is desirable to introduce measures that increase structure and transparency in the evaluation process so as to provide scientifically robust risk assessments that can be used for regulatory decision making. In this article we present results from workshop exercises with Nordic experts to illustrate how experts' evaluations regarding the reliability and relevance of (eco) toxicity studies for risk assessment may vary and discuss methods intended to promote structure and transparency in the evaluation process.

  • 50.
    Beronius, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vandenberg, Laura N.
    Using systematic reviews for hazard and risk assessment of endocrine disrupting chemicals2016In: Reviews in endocrine and metabolic disorders (Print), ISSN 1389-9155, E-ISSN 1573-2606, Vol. 16, no 4, p. 273-287Article, review/survey (Refereed)
    Abstract [en]

    The possibility that endocrine disrupting chemicals (EDCs) in our environment contribute to hormonally related effects and diseases observed in human and wildlife populations has caused concern among decision makers and researchers alike. EDCs challenge principles traditionally applied in chemical risk assessment and the identification and assessment of these compounds has been a much debated topic during the last decade. State of the science reports and risk assessments of potential EDCs have been criticized for not using systematic and transparent approaches in the evaluation of evidence. In the fields of medicine and health care, systematic review methodologies have been developed and used to enable objectivity and transparency in the evaluation of scientific evidence for decision making. Lately, such approaches have also been promoted for use in the environmental health sciences and risk assessment of chemicals. Systematic review approaches could provide a tool for improving the evaluation of evidence for decision making regarding EDCs, e.g. by enabling systematic and transparent use of academic research data in this process. In this review we discuss the advantages and challenges of applying systematic review methodology in the identification and assessment of EDCs.

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