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  • 201.
    Ek, Caroline
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mustajärvi, Lukas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Garbaras, Andrius
    Bariseviciute, Ruta
    Sapolaite, Justina
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlson, Agnes M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Using Compound-Specific and Bulk Stable Isotope Analysis for Trophic Positioning of Bivalves in Contaminated Baltic Sea Sediments2018Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, nr 8, s. 4861-4868Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Stable nitrogen isotopes (delta N-15) are used as indicators of trophic position (TP) of consumers. Deriving TP from delta N-15 of individual amino acids (AAs) is becoming popular in ecological studies, because of lower uncertainty than TP based on bulk delta N-15 (TPbulk). This method would also facilitate biomagnification studies provided that isotope fractionation is unaffected by toxic exposure. We compared TPAA and TPbulk estimates for a sediment-dwelling bivalve from two coastal sites, a pristine and a contaminated. Chemical analysis of PCB levels in mussels, sediments, and pore water confirmed the expected difference between sites. Both methods, but in particular the TPAA underestimated the actual TP of bivalves. Using error propagation, the total uncertainty related to the analytical precision and assumptions in the TP calculations was found to be similar between the two methods. Interestingly, the significantly higher intercept for the regression between T-AA, and TPbulk in the contaminated site compared to the pristine site indicates a higher deamination rate due to detoxification as a result of chronic exposure and a higher N-15 fractionation. Hence, there is a need for controlled experiments on assumptions underlying amino acid-specific stable isotope methods in food web and bimagnification studies.

  • 202.
    Ek, Caroline
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mustajärvi, Lukas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Garbaras, Andrius
    Bariseviciute, Ruta
    Sapolaite, Justina
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlson, Agnes M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Using compound-specific and bulk stable isotope analysis for trophic positioning of bivalves in contaminated Baltic sediments: a field evaluationManuskript (preprint) (Övrigt vetenskapligt)
  • 203.
    Ek, Caroline
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlson, Agnes M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hansson, Sture
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Stable Isotope Composition in Daphnia Is Modulated by Growth, Temperature, and Toxic Exposure: Implications for Trophic Magnification Factor Assessment2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 11, s. 6934-6942Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The potential for using stable isotope analysis in risk assessment of environmental contaminants is crucially dependent on the predictability of the trophic transfer of isotopes in food webs. The relationship between contaminant levels and trophic position of consumers is widely used to assess biomagnification properties of various pollutants by establishing trophic magnification factors (TMF). However, contaminant-induced variability of the isotopic composition in biota is poorly understood. Here, we investigated effects of toxic exposure on delta N-15 and delta C-13 values in a consumer, with a main hypothesis that these effects would be largely mediated via growth rate and metabolic turnover of the test animals. The cladoceran Daphnia magna was used in two experiments that were conducted to manipulate growth and body condition (assayed as C:N ratio) by food availability and temperature (Experiment 1) and by toxic exposure to the pesticide lindane (Experiment 2). We found a significant negative effect of growth rate and a positive effect of temperature on the consumer-diet discrimination factor for delta N-15 and delta C-13, with no effects on the C:N ratio (Experiment 1). In lindane-exposed daphnids, a significant growth inhibition was observed, with concomitant increase in metabolic costs and significantly elevated size-specific delta N-15 and delta C-13 values. Moreover, a significantly higher incorporation of carbon relative to nitrogen, yet a concomitant decrease in C:N ratio was observed in the exposed animals. Together, these results have methodological implications for determining trophic positions and TMF in polluted environments, where elevated delta N-15 values would translate into overestimated trophic positions and underestimated TMF. Furthermore, altered delta C-13 values may lead to erroneous food-chain assignment of the consumer in question.

  • 204.
    Ek, Caroline
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yu, Zhenyang
    Garbaras, Andrius
    Oskarsson, Hanna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Eriksson Wiklund, Ann-Kristin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kumblad, Linda
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Metabolic alterations in Gammarus spp. exposed to the beta-blocker propranolol: what causes the increase in stable isotope ratios?Manuskript (preprint) (Övrigt vetenskapligt)
  • 205.
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Review of the use of Ceramium tenuicorne growth inhibition test for testing toxicity of substances, effluents, products sediment and soil2017Ingår i: Estuarine, Coastal and Shelf Science, ISSN 0272-7714, E-ISSN 1096-0015, Vol. 195, s. 88-97Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A growth inhibition test has been developed based on two clones of the red macroalga Ceramium tenuicorne, one originating from 7 PSU and the other from 20 PSU. The species can be adapted to different salinities and the test can be carried out between 4 and 32 PSU. This test became an ISO standard in 2010 (ISO 107 10) for testing of chemicals and water effluents. In this study new and published data has been compiled on toxicity of single substances, waste waters from pulp mills, leachates from antifouling paints, harbour sediments and soil used for maintenance of leisure boats. The results show that the alga is sensitive to both metals and organic compounds and to biocides used in antifouling paints. By testing leachates from antifouling paints these could be ranked according to their toxicity. Similarly, the toxicity of waste waters from pulp mills was determined and the efficiency of secondary treatment evaluated. Further, the test method proved useful to test the toxicity in sediment samples. Sediments from small town harbours and ship lanes were shown to be harmful and compounds originating from antifouling paints were responsible for a large part of the inhibiting effect. The alga proved to be sensitive to contaminants leaking from boat yard soil. The growth inhibition test is a robust test that has high repeatability and reproducibility and easily can be applied on water, soil and sediment samples without being too costly. The species is found wort-wide in temperate waters, which makes the results relevant for large areas. In the Baltic Sea C tenuicorne is the most common red alga species and is thus particularly relevant for this area. The overall results show that contaminants from boat activities and the use of antifouling paints in particular pose a threat to the environment.

  • 206.
    Eklund, Britta
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hansson, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bengtsson, Henrik
    Eriksson Wiklund, Ann-Kristin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Pollutant Concentrations and Toxic Effects on the Red Alga Ceramium tenuicorne of Sediments from Natural Harbors and Small Boat Harbors on the West Coast of Sweden2016Ingår i: Archives of Environmental Contamination and Toxicology, ISSN 0090-4341, E-ISSN 1432-0703, Vol. 70, nr 3, s. 583-594Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This investigation set out to analyze the toxicity of surface sediments in a number of natural harbors and small boat harbors on the west coast of Sweden. This was done with the growth inhibition method with Ceramium tenuicorne. Also, concentrations of copper (Cu), lead (Pb), zinc (Zn), irgarol, organotin compounds, and polycyclic aromatic hydrocarbons (PAHs) in the sediments were analyzed. The small boat harbors were heavily polluted by Cu, Zn, butyltins, and PAHs, and to a lesser extent by Pb. The Cu, Pb, Zn, and butyltins probably originated from their past and/or present use in antifouling paints, whereas the PAHs probably had multiple sources, including boat motor exhausts. The measured toxicity of the sediment was generally related to their Cu, Zn, and butyltin content, although other toxic substances than those analyzed here probably contributed to the toxicity in some of the harbors. The natural harbor sediments contained less pollutants and were less toxic than the small boat harbor sediments. Nevertheless, our data indicate that the boating pressure today may be high enough to produce toxic effects even in natural harbors in pristine areas. The strongest relationship between toxicity and the major pollutants was obtained when the sediment toxicity was expressed as gram wet weight per liter compared with gram dry weight per liter and gram total organic carbon per liter. Hence, for pollutants that can be elutriated with natural sea water, sediment toxicity expressed as gram wet weight per liter appears preferable.

  • 207.
    Eklund, Britta
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Watermann, Burkard
    Persistence of TBT and copper in excess on leisure boat hulls around the Baltic Sea2018Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, nr 15, s. 14595-14605Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A handheld XRF-analyzer specially calibrated for measurements of metals on plastic boat hulls has been used on leisure boats in Denmark (DK), Finland (FI), and Germany (DE). The results on tin and copper are presented as mu g metal/cm(2). Tin is a proxy for the occurrence of organotin compounds on the boat. Two or three sites were visited in each country and between 25 and 90 boats were measured at each site. Every boat was measured at six to eight places, and the results are presented both as mean and median values. Linear regression of mean to median values of the 377 data pairs shows high relationship with R-2 = 0.9566 for tin and R-2 of 0.9724 for copper and thus both ways of calculation may be used. However, for regulative use, it is suggested that all individual measurements on each boat should be presented and used for decisions of removal or sealing of boat hulls. The results are compared with published data from different parts of Sweden, i.e., boats in fresh water, brackish water, and salt water. The results show that tin with mean values > 50 mu g Sn/cm(2) is still found on 42, 24, and 23% of the boats in DK, FI, and DE, respectively. The corresponding percentages based on median values are 38, 22, and 18% for DK, FI, and DE, respectively. The variation among boats is high with a maximum mean value of 2000 mu g Sn/cm(2). As comparison, one layer of an old TBT antifouling paint Hempels Hard racing superior, corresponds to 300 mu g Sn/cm(2). The percentage of boats with tin >400 mu g Sn/cm(2) content based on mean values was 10% in DK, 5% in FI, and 1% in DE. The corresponding median values were 9, 6, and 1% for DK, FI, and DE. Copper, >100 mu g Cu/cm(2), was detected on all measured boats in DK and in DE and on all but 3% of the FI boats. One layer of Hempels MilleXtra corresponds to I' 4000 mu g Cu/cm(2). The recommendation on the can is to apply two layers. The proportion of boats with higher mean copper values than 8000 mu g Cu/cm(2) was 51, 56, and 61 for boats in DK, FI, and DE, respectively. The proportion based on median values > 8000 mu g Cu/cm(2) was 50, 54, and 61% for DK, FI, and DE. The conclusion is that many leisure boats around the Baltic Sea still display or possess antifouling paints containing organotin compounds and that more than half of the boats have more copper than needed for one boat season according to the paint producers. Much of these known toxic compounds will probably be released into the environment and harm the biota. The calibrated XRF-method, intended for area measurements on boat hulls, is an easy and cheap way to detect boats with organotin compounds and high copper content. We recommend environmental authorities to use this method for identification of such boats and to use the results for requesting measures to minimize further leakage to the environment.

  • 208.
    El Beqqali, Aziza
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Novel Microextraction Techniques for Bioanalysis of Neurotransmitters and Biomarkers in Biological Fluids2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Sample preparation (sample pre-treatment) is the initial step and an essential part in bioanalysis procedure. The main role of sample preparation is to extract and transfer the analyte(s) of interest from a complex matrix to a purified media such as a pure solvent for analysis and quantification. Biological fluids are complex and contain, in addition to the target analyte(s), many different unwanted compounds from salts to proteins. Thus, the analysis of these samples requires an effective sample preparation method prior to the liquid chromatography-mass spectrometry (LC/MS) and gas chromatography-mass spectrometry (GC/MS) assays. The aim of the present work was to evaluate micro-extraction by packed sorbent (MEPS) and develop new sample preparation techniques for the extraction of neurotransmitters and biomarkers from biological samples. Moreover, two new sample preparation techniques were developed. The first developed technique is molecular imprinting on polysulfone membrane (MIPM), and the second one is molecularly imprinted polymer in tablet form (MIPT).

    MEPS is a well-known sample preparation technique that can be used online with analytical instruments without any modifications. In this thesis, MEPS was used online with liquid chromatography-tandem mass spectrometry (LC/MS/MS) for the quantification of dopamine and serotonin in human urine samples (Study I) and with GC/MS for the analysis of methadone in humane urine (Study II). Polystyrene polymer and silica-C8 were used as sorbent in Study I and Study II, respectively. In both studies, small sample volumes (50 µL) were used and full method validation was performed. In both studies (I and II), MEPS enhanced the limit of detection (LOD) and reduced the extraction time compared to the previously published methods. In Study I, the mean accuracies of quality control (QC) samples of dopamine and serotonin were 99–101% while the precision values (RSD) were 6–11%. In Study II, the accuracy values of methadone were between 97 and 107% while the precisions (RSD) were between 11 and 15%.

    MIP-sol-gel on polysulfone membrane (MIPM) was developed and used in combination with MEPS for the extraction of hippuric acid (HA) in plasma and urine samples (Study III). A good selectivity was obtained using plasma and urine samples. The precision of QC samples in plasma and urine samples were 2.2–4.8% and 1.1–6.7%, respectively. The method recovery was above 90%.

    In Study IV, a new technique was developed using a tablet form of molecularly imprinted sol-gel (MIPT) for the extraction of methadone from human plasma samples. Methadone-d9 was selected as the template for accurate recovery, and 3-(propyl methacrylate) trimethoxysilane (3PMTMOS) was used as a precursor. The extraction recovery was higher than 80%. The LOD and LLOQ were 1.0 and 5.0 ng mL-1, respectively. The validation showed good selectivity, accuracy and precision.

    In Study I, III and IV, LC/MS/MS system was used while GC/MS was used in Study II for the separation and detection of target analytes.

    There will always be a high demand for rapid, selective, reliable and sensitive techniques for sample preparation. It is convenient to use molecular dynamics simulations as a theoretical tool for the optimization of molecularly imprinted system. Suitable monomers and cross-linkers are crucial to synthesize the new membrane and tablet molecular imprinted polymer platforms for all kinds of molecules.

  • 209.
    El Beqqali, Aziza
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ahmadi, Mazaher
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Determination of AZD6118 in dog plasma samples utilizing microextraction by packed sorbent and liquid chromatography-electrospray ionization tandem mass spectrometry2017Ingår i: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 1043, s. 20-24Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, for the first time, a method has been developed for the determination of AZD6118, a candidate drug, in dog plasma samples. The method is based on microextraction by packed sorbent (MEPS) of the drug prior to liquid chromatography-electrospray ionization tandem mass spectrometry assay. Various important factors affecting MEPS performance were optimized, and under the optimized condition, a linear calibration curve in the concentration range of 20-25,000 nmol L-1 with a coefficient of determination over 0.99 was obtained. The back-calculated values of the calibration points showed good agreement with the theoretical concentrations (coefficients of variation percent between 0.3-3.8). The lower limit of quantification and limit of detection were 20.0 and 2.9 nmol L-1, respectively. The repeatability and accuracy of the method was evaluated by determination of quality control samples at three concentration levels (low, medium and high) using the developed method, and the results (coefficients of variation values were between 1.9% and 3.2%, relative recoveries ranged between 93.5-102.1%) confirm that a powerful method has been developed for the extraction and determination of the investigated drug in dog plasma.

  • 210.
    El-Beqqali, Aziza
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: I. Determination of methadone in human plasma utilizing liquid chromatography-tandem mass spectrometry2016Ingår i: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 936, s. 116-122Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the present work molecularly imprinted sol-gel tablet (MIP-Tablet) was prepared. The MIP-sol-gel was prepared as a thin layer on polyethylene material in a tablet form. Methadone-d9 was selected as the template and 3-(propylmethacrylate)-trimethoxysilane was used as precursor. MIP-Tablet was applied for micro-solid phase extraction (μ-SPE). The MIP-Tablet was used for the determination of methadone in human plasma samples utilizing liquid chromatography-tandem mass spectrometry; and each tablet could be used twenty times. The extraction time was 10 min while desorption time was 6 min. Factors affecting the extraction efficiency such as desorption solvents, sample pH, salt addition, extraction time, desorption time and adsorption capacity were investigated. The calibration curves were obtained within the range of 5-5000 ng/mL using methadone in human plasma samples. The coefficients of determination (r(2)) values were >= 0.999 for all runs and the extraction recovery was >80%. The accuracy values for quality control samples varied from +3.6 to +9.7% and the inter-day precision (RSD %) values were ranged from 5.0 to 8.0%. The limit of detection was 1.0 ng/mL and the lower limit of quantification was 5 ng/mL utilizing methadone in human plasma samples.

  • 211.
    El-Beqqali, Aziza
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andersson, Lars I.
    Jeppsson, Amin Dadoun
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Molecularly imprinted polymer-sol-gel tablet toward micro-solid phase extraction: II. Determination of amphetamine in human urine samples by liquid chromatography tandem mass spectrometry2017Ingår i: Journal of chromatography. B, ISSN 1570-0232, E-ISSN 1873-376X, Vol. 1063, s. 130-135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Amphetamine selective molecularly imprinted sol-gel polymer tablets, MIP-tablets, for solid-phase micro extraction of biofluid samples were prepared. An acetonitrile solution of deuterated amphetamine template and silane precursor, 3-(propylmethacrylate) trimethoxysilane, was soaked into the pores of polyethylene tablet substrates and polymerized by an acid-catalysed sol-gel process. Application of the resultant MIP-tablets to extract amphetamine from human urine samples followed by LC-MS/MS analysis was investigated. The extraction protocol was optimised with respect to pH of sample, addition of sodium chloride, extraction time, desorption solvent and desorption time. The final analysis method determined amphetamine in human urine with a limit of detection (LOD) of 1.0 ng/mL and a lower limit of quantification (LLOQ) of 5 ng/mL. Validation demonstrated accuracy of the method was 91.0-104.0% and inter-assay precision was 4.8-8.5% (RSD). Extraction recovery was 80%. The MIP-tablets could be re-used and the same tablet could be employed for more than twenty extractions.

  • 212. Elliott, John F.
    et al.
    Ramzy, Ahmed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Nilsson, Ulrika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Moffat, Wayne
    Suzuki, Kunimasa
    Severe intractable eyelid dermatitis probably caused by exposure to hydroperoxides of linalool in a heavily fragranced shampoo2017Ingår i: Contact Dermatitis, ISSN 0105-1873, E-ISSN 1600-0536, Vol. 76, nr 2, s. 114-115Artikel i tidskrift (Övrigt vetenskapligt)
  • 213. Elm, Jonas
    et al.
    Myllys, Nanna
    Olenius, Tinja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Halonen, Roope
    Kurtén, Theo
    Vehkamäki, Hanna
    Formation of atmospheric molecular clusters consisting of sulfuric acid and C8H12O6 tricarboxylic acid2017Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 19, nr 6, s. 4877-4886Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Using computational methods, we investigate the formation of atmospheric clusters consisting of sulfuric acid (SA) and 3-methyl-1,2,3-butanetricarboxylic acid (MBTCA), identified from a-pinene oxidation. The molecular structure of the clusters is obtained using three different DFT functionals (PW91, M06-2X and oB97X-D) with the 6-31++ G(d, p) basis set and the binding energies are calculated using a high level DLPNO-CCSD(T)/ Def2-QZVPP method. The stability of the clusters is evaluated based on the calculated formation free energies. The interaction between MBTCA and sulfuric acid is found to be thermodynamically favourable and clusters consisting of 2-3 MBTCA and 2-3 SA molecules are found to be particularly stable. There is a large stabilization of the cluster when the amount of sulfuric acid-carboxylic acid hydrogen bonded interactions is maximized. The reaction free energies for forming the (MBTCA) 2-3(SA) 2-3 clusters are found to be similar in magnitude to those of the formation of the sulfuric acid-dimethylamine cluster. Using cluster kinetics calculations we identify that the growth of the clusters is essentially limited by a weak formation of the largest clusters studied, implying that other stabilizing vapours are required for stable cluster formation and growth.

  • 214.
    Elmongy, Hatem
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Analytical Methods For Sports Drugs: Challenges and Approaches2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Drugs used to enhance human performance in sport competitions are prohibited by the world anti-doping association (WADA). Biological samples from athletes are continuously tested for adverse analytical findings regarding the identity and/or quantity of the banned substances. The current thesis deals with the development of new analytical methods to determine the concentrations of certain drugs used by athletes and even by regular users for therapeutic purposes. The developed methods aim to analyze the contents of these drugs in the biological matrices; plasma, serum and saliva to provide a successful approach towards either doping detection or therapeutic monitoring. β-adrenergic blockers such as propranolol and metoprolol are used in sports to relief stress and as therapeutic agents in the treatment of hypertension. Both drugs are in chiral forms and available only as racemic mixtures. The different pharmacology of each enantiomer necessitates the monitoring of each enantiomer by stereoselective analytical technique such as chiral liquid chromatography for separation and mass spectrometry for selective detection. The Endogenous anabolic androgenic steroids (EAAS) on the other hand are only notoriously used in sports to increase muscle mass and strength. A method utilizing high-resolution mass spectrometry (HRMS) coupled to ultra-high performance liquid chromatography (UHPLC) was developed for the simultaneous determination of EAAS and their conjugated metabolites to provide a better insight into the steroidal module of the athlete biological passport (ABP). Moreover, the steroidal profile was assessed in serum using the proposed method after the administration of Growth hormone injection as an approach toward the implementation of a new endocrinological module based on steroids biomarkers to hormone doping.  Biological samples contain many components that may interfere with the analytical measurements. Therefore, sample preparation methods were developed using solid phase extraction (SPE) and miniaturized techniques such as microextraction by packed sorbents (MEPS) for the purification and pre-concentration of analytes prior to LC/MS analysis.

  • 215.
    Elmongy, Hatem
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Development and validation of a UHPLC-HRMS method for the simultaneous determination of the endogenous anabolic androgenic steroids in human serumManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Being performance enhancing hormones, endogenous anabolic androgenic steroids (EAAS) are banned from most competitive sports by the World Anti-doping Agency (WADA).. In anti-doping control laboratories, routine assays are mainly performed on urine samples of athletes in and out of competitions. Serum constitutes a promising alternative to urine as it is less subjected to manipulation or contamination issues that may influence the method sensitivity. The simultaneous determination of EAAS and their conjugated metabolites is very challenging due to their contradicting chemical behaviors at the ionization interface of the mass spectrometer. This may prejudice their detection or limit the method sensitivity. Herein, we have addressed these challenges and developed a new method for the simultaneous determination of unconjugated, sulphate and glucuronide EAAS (Androsterone, Etiocholanolone, testosterone, epitestosterone, dihydrotestosterone, dehydroepiandrosterone, androstenedione and 17a-hydroxyprogesterone) in human serum using ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS). The use of mass spectrometric detection in full scan mode facilitated the study of the most versatile adducts for detection and quantitation. Using solid phase extraction as sample preparation protocol prior to analysis, the method limits of quantitation ranged from 0.006 to 7.904 ng/mL and the recoveries ranged from 70.2 to 96.5 %. The method calibration was performed in untreated serum representing realistic matrix composition with correlation coeffecients ranged from 0.9859 to 0.9988. Finally, the serum- levels of the investigated steroids were determined in 4 male and 1 female human subject to provide estimates of baseline levels based on individual values.

  • 216.
    Elmongy, Hatem
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Longitudinal studies of putative growth hormone (GH) biomarkers and hematological and steroidal parameters in relation to 2 weeks administration of human recombinant GHManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Detection of low doses of recombinant growth hormone is a challenge in anti-doping testing. Future testing leads toward longitudinal monitoring of IGF-I and P-III-NP in an endocrine module. Additional biomarkers, for example vitamin D binding protein, alpha-HS-glycoprotein, fibronectin 1 and decoin have been identified in different omics studies. Here we have longitudinally studied the usefulness of these putative biomarkers in relation to two weeks administration of low doses of recombinant growth hormone in healthy male volunteers. Moreover, we studied the hematological parameters included in the athlete biological passport as well as serum concentration of dihydrotestosterone-sulfate. Alpha-HS-glycoprotein decreased 25 % up to three weeks after treatment period (p˂0.05), whereas fibronectin increased 20 % during the treatment (p˂0.05). The addition of these two biomarkers increased the likelihood to detect recombinant growth hormone intake based on individual calculated thresholds in some of the participants as compared to the GH2000 score. A minor 10 % increase (p=0.003) in reticulocytes percentage and OFF-score was observed, but the changes did not lead to any atypical profile based on individual passport thresholds. Vitamin D binding protein, decoin and dihydrotestosterone-sulfate were not affected by recombinant growth hormone. Dihydrotestosterone-sulfate was negatively correlated with the IGF-I biomarker at baseline (R=-0.50, p=0.003) and post dose (R=-0.59, p=0.01). In conclusion we have verified Alpha-HS-glycoprotein and fibronectin 1 as promising future biomarkers for detecting low doses of recombinant growth hormone and further studies of these proteins are encouraged.

  • 217.
    Elmongy, Hatem
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Damanhour University, Egypt.
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Saliva as an alternative specimen to plasma for drug bioanalysis: A review2016Ingår i: TrAC. Trends in analytical chemistry, ISSN 0165-9936, E-ISSN 1879-3142, Vol. 83, s. 70-79Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Saliva provides a suitable medium for screening and determination of drugs. It is easy to collect and handle besides the non-invasive sampling. Extraction techniques such as micro-extraction by packed sorbent (MEPS) and dried saliva spot (DSS) provides fast and efficient recovery of the analytes. Moreover, MEPS could be fully automated to ascertain method reproducibility and DSS provides fast simultaneous collection and extraction of samples. Several studies were conducted to determine drugs in saliva in correlation to plasma aiming to establish rigid evidence on the suitability of saliva in monitoring of drug levels. Only free drug could be present in salivary fluid thus protein binding of drugs affect markedly on the salivary levels of drugs. Pharmacokinetic parameters could be determined for drugs in saliva with emphasis on diffusion parameters of drugs to salivary fluid such as pH and drug lipophilicity. Screening techniques are mainly based on mass spectrometry (MS) with an emphasis on Liquid Chromatography-Mass Spectrometry (LC-MS), due to limited sample volumes and the low detection limits. Saliva could make drug testing outside laboratory environments feasible with the appropriate techniques for analysis. This review focuses on the developments and challenges in testing of drugs in saliva in correlation to plasma and application to drug analysis in saliva regarding therapeutic drug monitoring and pharmacokinetics.

  • 218.
    Elmongy, Hatem
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Damanhour University, Egypt.
    Ahmed, Hytham
    Wahbi, Abdel-Aziz
    Amini, Ahmad
    Colmsjö, Anders
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Determination of metoprolol enantiomers in human plasma and saliva samples utilizing microextraction by packed sorbent and liquid chromatography-tandem mass spectrometry2016Ingår i: BMC Biomedical chromotography, ISSN 0269-3879, E-ISSN 1099-0801, Vol. 30, nr 8, s. 1309-1317Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A sensitive, accurate and reliable bioanalytical method for the enantioselective determination of metoprolol in plasma and saliva samples utilizing liquid chromatography-electrospray ionization tandem mass spectrometry was developed and validated. Human plasma and saliva samples were pretreated by microextraction by packed sorbent (MEPS) prior to analysis. A new MEPS syringe form with two inputs was used. Metoprolol enantiomers and internal standard pentycaine (IS) were eluted from MEPS sorbent using isopropanol after removal of matrix interferences using aliquots of 5% methanol in water. Complete separation of metoprolol enantiomers was achieved on a Cellulose-SB column (150x4.6mm, 5m) using isocratic elution with mobile phase 0.1% ammonium hydroxide in hexane-isopropanol (80:20, v/v) with a flow rate of 0.8mL/min. A post-column solvent-assisted ionization was applied to enhance metoprolol ionization signal in positive mode monitoring (+ES) using 0.5% formic acid in isopropanol at a flow rate of 0.2mL/min. The total chromatographic run time was 10min for each injection. The detection of metoprolol in plasma and saliva samples was performed using triple quadrupole tandem mass spectrometer in +ES under the following mass transitions: m/z 268.0872.09 for metoprolol and m/z 303.3154.3 for IS. The linearity range was 2.5-500ng/mL for both R- and S-metoprolol in plasma and saliva. The limits of detection and quantitation for both enantiomers were 0.5 and 2.5ng/mL respectively, in both matrices (plasma and saliva). The intra- and inter-day precisions were presented in terms of RSD values for replicate analysis of quality control samples and were <5%; the accuracy of determinations varied from 96 to 99%. The method was able to determine the therapeutic levels of metoprolol enantiomers in both human plasma and saliva samples successfully, which can aid in therapeutic drug monitoring in clinical laboratories.

  • 219.
    Elmongy, Hatem
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Damanhour University, Egypt.
    Ahmed, Hytham
    Wahbi, Abdel-Aziz
    Koyi, Hirsh
    Abdel-Rehim, Mohamed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Online post-column solvent assisted and direct solvent-assisted electrospray ionization for chiral analysis of propranolol enantiomers in plasma samples2015Ingår i: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1418, s. 110-118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An Online post-column solvent-assisted ionization (OPSAI) method was developed for enhancing the ionization of the beta-blocker propranolol utilizing normal phase LC-MS/MS. Solvent-assisted electrospray ionization (SAESI) was studied by the introduction of the assistant solvents A: 0.5% Formic acid in Isopropanolol, B: 0.5% Formic acid in lsopropanolol-Water (1:1), and C: 0.5% Formic acid in water into the electrospray ionization chamber using a spray needle. Analyte molecules can be directly ionized by the aid of the assistant solvent spray. Both methods were applied to the chiral separation of propranolol enantiomers using normal phase analysis on cellulose-based chiral column. Interestingly, both methods are easy to handle and offer a wide range of assistant solvents that can be used in order to gain the optimum ionization of the analyte molecules. The both methods considerably improved the analyte signal and the peak area greatly increased. The propranolol average signal-to-noise (S/N) ratio was enhanced from 26 +/- 1 and 42 +/- 1 to 2341 +/- 61 and 1725 +/- 29 for R-propranolol and S-propranolol, respectively, when the post-column solvent method (OPSAI) was used with isopropanol-assistant solvent (A). While in case of solvent-assisted electrospray ionization method (SAESI) signal was enhanced from 26 +/- 1 and 42 +/- 1 to 2223 +/- 72 and 2155 +/- 58 for R-propranolol and S-propranolol, respectively, with water as an assistant solvent. The limit of detection was 10 ng/mL and the method was linear in the range 50-2000 ng/mL. The NPLC-MS method was applied for the determination of propranolol enantiomers in human plasma after microextraction by packed C18 sorbent.

  • 220. Enell, Anja
    et al.
    Lundstedt, Staffan
    Arp, Hans Peter H.
    Josefsson, Sarah
    Cornelissen, Gerard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Norwegian Geotechnical Institute (NGI), Norway.
    Wik, Ola
    Berggren Kleja, Dan
    Combining Leaching and Passive Sampling To Measure the Mobility and Distribution between Porewater, DOC, and Colloids of Native Oxy-PAHs, N-PACs, and PAHs in Historically Contaminated Soil2016Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, nr 21, s. 11797-11805Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Different methods to quantify soil porewater concentrations of contaminants will provide different types of information. Passive sampling measurements give freely dissolved porewater concentrations (C-pw,C-free), while leaching tests provide information on the mobile concentration (C-pw,C-leach), including contaminants associated with dissolved organic carbon (DOC) and particles/colloids in the porewater. This study presents a novel combination of these two measurements, to study the sorption and mobility of polycyclic aromatic compounds (PACs) to DOC and particulate organic carbon (POC) in 10 historically contaminated soils. The PACs investigated were polycyclic aromatic hydrocarbons (PAHs), oxygenated-PAHs, and nitrogen containing heterocyclic PACs. Observed C-pw,C-leach was up to 5 orders of magnitude higher than C-pw,C-free; implying large biases when C-pw,C-leach is used to assess bioavailability or soil partitioning. Sorption of PACs to DOC and POC was important for the mobility of compounds with log K-OW > 4. Average DOC/water-partitioning coefficients (K-DOC) correlated well with KOW (log K-DOC = 0.89 x log K-OW +1.03 (r(2) = 0.89)). This relationship is likely more accurate for historically contaminated soils than previously published data, which suffer from artifacts caused by problems in measuring C-pw,C-free correctly or not using historically contaminated soils. POC/water-partitioning coefficients (K-POC) were orders of magnitude larger than corresponding K-DOC, suggesting sorption to mobile particles/colloids is the dominant mechanism for PAC mobility.

  • 221. Erb, Karl-Heinz
    et al.
    Kastner, Thomas
    Plutzar, Christoph
    Bais, Anna Liza S.
    Carvalhais, Nuno
    Fetzel, Tamara
    Gingrich, Simone
    Haberl, Helmut
    Lauk, Christian
    Iedertscheider, Maria N.
    Pongratz, Julia
    Thurner, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Luyssaert, Sebastiaan
    Unexpectedly large impact of forest management and grazing on global vegetation biomass2018Ingår i: Nature, ISSN 0028-0836, E-ISSN 1476-4687, Vol. 553, nr 7686, s. 73-76Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Carbon stocks in vegetation have a key role in the climate system(1-4). However, the magnitude, patterns and uncertainties of carbon stocks and the effect of land use on the stocks remain poorly quantified. Here we show, using state-of-the-art datasets, that vegetation currently stores around 450 petagrams of carbon. In the hypothetical absence of land use, potential vegetation would store around 916 petagrams of carbon, under current climate conditions. This difference highlights the massive effect of land use on biomass stocks. Deforestation and other land-cover changes are responsible for 53-58% of the difference between current and potential biomass stocks. Land management effects (the biomass stock changes induced by land use within the same land cover) contribute 42-47%, but have been underestimated in the literature. Therefore, avoiding deforestation is necessary but not sufficient for mitigation of climate change. Our results imply that trade-offs exist between conserving carbon stocks on managed land and raising the contribution of biomass to raw material and energy supply for the mitigation of climate change. Efforts to raise biomass stocks are currently verifiable only in temperate forests, where their potential is limited. By contrast, large uncertainties hinder verification in the tropical forest, where the largest potential is located, pointing to challenges for the upcoming stocktaking exercises under the Paris agreement.

  • 222. Faassen, Elisabeth J.
    et al.
    Antoniou, Maria G.
    Beekman-Lukassen, Wendy
    Blahova, Lucie
    Chernova, Ekaterina
    Christophoridis, Christophoros
    Combes, Audrey
    Edwards, Christine
    Fastner, Jutta
    Harmsen, Joop
    Hiskia, Anastasia
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kaloudis, Triantafyllos
    Lopicic, Srdjan
    Lürling, Miquel
    Mazur-Marzec, Hanna
    Meriluoto, Jussi
    Porojan, Cristina
    Viner-Mozzini, Yehudit
    Zguna, Nadezda
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    A Collaborative Evaluation of LC-MS/MS Based Methods for BMAA Analysis: Soluble Bound BMAA Found to Be an Important Fraction2016Ingår i: Marine Drugs, ISSN 1660-3397, E-ISSN 1660-3397, Vol. 14, nr 3, artikel-id 45Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Exposure to beta-N-methylamino-l-alanine (BMAA) might be linked to the incidence of amyotrophic lateral sclerosis, Alzheimer's disease and Parkinson's disease. Analytical chemistry plays a crucial role in determining human BMAA exposure and the associated health risk, but the performance of various analytical methods currently employed is rarely compared. A CYANOCOST initiated workshop was organized aimed at training scientists in BMAA analysis, creating mutual understanding and paving the way towards interlaboratory comparison exercises. During this workshop, we tested different methods (extraction followed by derivatization and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis, or directly followed by LC-MS/MS analysis) for trueness and intermediate precision. We adapted three workup methods for the underivatized analysis of animal, brain and cyanobacterial samples. Based on recovery of the internal standard D(3)BMAA, the underivatized methods were accurate (mean recovery 80%) and precise (mean relative standard deviation 10%), except for the cyanobacterium Leptolyngbya. However, total BMAA concentrations in the positive controls (cycad seeds) showed higher variation (relative standard deviation 21%-32%), implying that D(3)BMAA was not a good indicator for the release of BMAA from bound forms. Significant losses occurred during workup for the derivatized method, resulting in low recovery (<10%). Most BMAA was found in a trichloroacetic acid soluble, bound form and we recommend including this fraction during analysis.

  • 223. Fahlgren, Camilla
    et al.
    Gómez-Consarnau, Laura
    Zábori, Julia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindh, Markus V.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mårtensson, E. Monica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Uppsala University, Sweden.
    Nilsson, Douglas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Pinhassi, Jarone
    Seawater mesocosm experiments in the Arctic uncover differential transfer of marine bacteria to aerosols2015Ingår i: Environmental Microbiology Reports, ISSN 1758-2229, E-ISSN 1758-2229, Vol. 7, nr 3, s. 460-470Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biogenic aerosols critically control atmospheric processes. However, although bacteria constitute major portions of living matter in seawater, bacterial aerosolization from oceanic surface layers remains poorly understood. We analysed bacterial diversity in seawater and experimentally generated aerosols from three Kongsfjorden sites, Svalbard. Construction of 16S rRNA gene clone libraries from paired seawater and aerosol samples resulted in 1294 sequences clustering into 149 bacterial and 34 phytoplankton operational taxonomic units (OTUs). Bacterial communities in aerosols differed greatly from corresponding seawater communities in three out of four experiments. Dominant populations of both seawater and aerosols were Flavobacteriia, Alphaproteobacteria and Gammaproteobacteria. Across the entire dataset, most OTUs from seawater could also be found in aerosols; in each experiment, however, several OTUs were either selectively enriched in aerosols or little aerosolized. Notably, a SAR11 clade OTU was consistently abundant in the seawater, but was recorded in significantly lower proportions in aerosols. A strikingly high proportion of colony-forming bacteria were pigmented in aerosols compared with seawater, suggesting that selection during aerosolization contributes to explaining elevated proportions of pigmented bacteria frequently observed in atmospheric samples. Our findings imply that atmospheric processes could be considerably influenced by spatiotemporal variations in the aerosolization efficiency of different marine bacteria.

  • 224. Fang, Shuhong
    et al.
    Li, Cheng
    Zhu, Lingyan
    Yin, Hongling
    Yang, Yingchun
    Ye, Zhixiang
    Cousins, Ian T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Spatiotemporal distribution and isomer profiles of perfluoroalkyl acids in airborne particulate matter in Chengdu City, China2019Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 689, s. 1235-1243Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Airborne particulate matter (APM) was collected in four seasons at five different areas of the city of Chengdu, China to study the spatial and seasonal contamination pattern of perfluoroalkyl acids (PFAAs). The results showed that Sigma PFAA concentrations in Downtown Chengdu (mean value: 297 +/- 238 pg/m(3)) were higher than concentrations in suburban areas. The highest concentrations of PFAAs occurred during spring (97.5-709 pg/L; arithmetic mean concentration: 297 +/- 191 pg/L) while the lowest concentration occurred during autumn (9.27-105 pg/L; arithmetic mean concentration 41.1 +/- 24.8 pg/L). Perfluorooctanoic acid (PFOA) was the main PFAA quantified during winter, summer and autumn, and perfluorononanoic acid (PFNA) was the predominant PFAA in spring. Relative humidity (RH) and average daily precipitation (PRE) showed significant negative correlations with PFAA concentrations in winter and summer, suggesting that they played an important role in controlling PFAA concentrations in APM. The linear structural isomer of PFOA (n-PFOA) was the most abundant isomer in APM in Chengdu, with the average proportion of 85.6% +/- 6.13%, higher than the proportion in ECF PFOA commercial products (74.3-77.6%). However, the consistent fingerprint of branched PFOA in the APM implies that ECF PFOA makes a significant contribution to the PFOA in APM. PEELS in the APM collected throughout the year had a mean proportion of 54.0 +/- 8.81% of n-PFOS. This proportion of n-PFOS is lower than commercial ECF products (62.9-78.2%), suggesting an additional proportion of branched PFOS isomers in APM in Chengdu.

  • 225.
    Fang, Wenzheng
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Zheng, Mei
    Lee, Meehye
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kim, Sang-Woo
    Du, Ke
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Divergent Evolution of Carbonaceous Aerosols during Dispersal of East Asian Haze2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 10422Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Wintertime East Asia is plagued by severe haze episodes, characterized by large contributions of carbonaceous aerosols. However, the sources and atmospheric transformations of these major components are poorly constrained, hindering development of efficient mitigation strategies and detailed modelling of effects. Here we present dual carbon isotope (delta C-13 and Delta C-14) signatures for black carbon (BC), organic carbon (OC) and water-soluble organic carbon (WSOC) aerosols collected in urban (Beijing and BC for Shanghai) and regional receptors (e.g., Korea Climate Observatory at Gosan) during January 2014. Fossil sources (>50%) dominate BC at all sites with most stemming from coal combustion, except for Shanghai, where liquid fossil source is largest. During source-to-receptor transport, the delta C-13 fingerprint becomes enriched for WSOC but depleted for water-insoluble OC (WIOC). This reveals that the atmospheric processing of these two major pools are fundamentally different. The photochemical aging (e.g., photodissociation, photooxidation) during formation and transport can release CO2/CO or short-chain VOCs with lighter carbon, whereas the remaining WSOC becomes increasingly enriched in delta C-13. On the other hand, several processes, e.g., secondary formation, rearrangement reaction in the particle phase, and photooxidation can influence WIOC. Taken together, this study highlights high fossil contributions for all carbonaceous aerosol sub-compartments in East Asia, and suggests different transformation pathways for different classes of carbonaceous aerosols.

  • 226.
    Fang, Wenzheng
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. East China Normal University, China.
    Du, Ke
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Xing, Zhenyu
    Cho, Chaeyoon
    Kim, Sang-Woo
    Deng, Junjun
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Dual-Isotope Constraints on Seasonally Resolved Source Fingerprinting of Black Carbon Aerosols in Sites of the Four Emission Hot Spot Regions of China2018Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 123, nr 20, s. 11735-11747Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Despite much recent efforts, the emission sources of black carbon (BC) aerosols. central input to understanding and predicting environmental and climate impact. remain highly uncertain. Here we present observational delta C-13/Delta C-14-based constraints on the sources of BC aerosols over the four seasons in each of the four key hot spot emission regions of China: Beijing-Tianjin-Hebei (BTH-Wuqing; where Wuqing is the sampling location), Yangtze River Delta (YRD-Haining), Pearl River Delta (PRD-Zhongshan), and Sichuan Basin (SC-Deyang). Overall, BC loadings were highest in winter, yet elevated loadings were also observed in other seasons, for example, spring at SC-Deyang and fall at PRD-Zhongshan. Annually, the dominant BC sources were coal (50 +/- 20%) for BTH-Wuqing, liquid fossil for YRD-Haining (46 +/- 8%) and PRD-Zhongshan (48 +/- 18%), whereas liquid fossil (42 +/- 17%) and biomass burning (41 +/- 14%) equally affected SC-Deyang. There is also different but distinct seasonalities in BC sources for the different sites. As an example, for BTH-Wuqing coal burning increased from summer to winter, while summer and spring BTH-Wuqing were more influenced by liquid fossil. In contrast, for YRD-Haining, the relative importance of emission sources was more constant over the year. These quantitative observational constraints on source-seasonality of BC aerosols in receptor sites located in China's four key economic zones highlight that regulatory control on BC aerosol emissions from different fuels should consider both seasonal and regional variations. Our results also suggest that models on estimates of BC-induced climate and air quality should consider variations over both regional and seasonal scales.

  • 227. Faxneld, Suzanne
    et al.
    Berger, Urs
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Helmholtz Centre for Environmental Research—UFZ, Germany.
    Helander, Björn
    Danielsson, Sara
    Miller, Aroha
    Nyberg, Elisabeth
    Persson, Jan-Olov
    Stockholms universitet, Naturvetenskapliga fakulteten, Matematiska institutionen.
    Bignertt, Anders
    Temporal Trends and Geographical Differences of Perfluoroalkyl Acids in Baltic Sea Herring and White-Tailed Sea Eagle Eggs in Sweden2016Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, nr 23, s. 13070-13079Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Temporal and spatial trends of perfluoroalkyl acids (PFAAs) were investigated in Baltic Sea herring liver (Clupea harengus) from three sites, and white-tailed sea eagle (WTSE) eggs (Haliaeetus albicilla) from two freshwater and two marine areas in Sweden. Trends of most quantifiable PFAAs increased over the monitored period (1980-2014 in herring, 1960s/1980s-2010 in WTSE). No significant decreasing trends were observed for the most recent ten years for any substances, except perfluorooctane sulfonamide (FOSA). Concentrations of perfluorooctanesulfonic acids (PFOS) in herring showed a distinct decreasing spatial trend moving from the more southern site toward the more northern site, indicating main input of PFOS into the southern Baltic Sea. For WTSE, PFOS concentration was higher in the marine compared to the freshwater environment, explained by the cumulative historic contamination of the Baltic Sea. Similarly, concentrations in WTSE were lower in the northern part of the Baltic Sea compared to further south. Concentrations of PFUnDA, representing long-chain perfluoroalkyl carboxylic acids (PFCAs), showed a more homogeneous spatial distribution compared to PFOS for both herring and WTSE, indicating that atmospheric inputs (via precursors) of the long-chain PFCAs are important contributors in the study areas.

  • 228. Feng, X.
    et al.
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmes, R. M.
    Vonk, J. E.
    van Dongen, B. E.
    Semiletov, I. P.
    Dudarev, O. V.
    Yunker, M. B.
    Macdonald, R. W.
    Montluon, D. B.
    Eglinton, T. I.
    Multi-molecular tracers of terrestrial carbon transfer across the pan-Arctic: comparison of hydrolyzable components with plant wax lipids and lignin phenols2015Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 12, nr 15, s. 4841-4860Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hydrolyzable organic carbon (OC) comprises a significant component of sedimentary particulate matter transferred from land into oceans via rivers. Its abundance and nature are however not well studied in Arctic river systems, and yet may represent an important pool of carbon whose fate remains unclear in the context of mobilization and related processes associated with a changing climate. Here, we examine the molecular composition and source of hydrolyzable compounds isolated from sedimentary particles derived from nine rivers across the pan-Arctic. Bound fatty acids (b-FAs), hydroxy FAs, n-alkane-alpha,omega-dioic acids (DAs) and phenols were the major components released upon hydrolysis of these sediments. Among them, b-FAs received considerable inputs from bacterial and/or algal sources, whereas omega-hydroxy FAs, mid-chain substituted acids, DAs, and hydrolyzable phenols were mainly derived from cutin and suberin of higher plants. We further compared the distribution and fate of suberin- and cutin-derived compounds with those of other terrestrial biomarkers (plant wax lipids and lignin phenols) from the same Arctic river sedimentary particles and conducted a benchmark assessment of several biomarker-based indicators of OC source and extent of degradation. While suberin-specific biomarkers were positively correlated with plant-derived high-molecular-weight (HMW) FAs, lignin phenols were correlated with cutin-derived compounds. These correlations suggest that, similar to leaf-derived cutin, lignin was mainly derived from litter and surface soil horizons, whereas suberin and HMW FAs incorporated significant inputs from belowground sources (roots and deeper soil). This conclusion is supported by the negative correlation between lignin phenols and the ratio of suberin-to-cutin biomarkers. Furthermore, the molecular composition of investigated biomarkers differed between Eurasian and North American Arctic rivers: while lignin dominated in the terrestrial OC of Eurasian river sediments, hydrolyzable OC represented a much larger fraction in the sedimentary particles from Colville River. Hence, studies exclusively focusing on either plant wax lipids or lignin phenols will not be able to fully unravel the mobilization and fate of bound OC in Arctic rivers. More comprehensive, multi-molecular investigations are needed to better constrain the land-ocean transfer of carbon in the changing Arctic, including further research on the degradation and transfer of both free and bound components in Arctic river sediments.

  • 229. Feng, Xiaojuan
    et al.
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmes, R. Max
    Vonk, Jorien E.
    van Dongen, Bart E.
    Semiletov, Igor P.
    Dudarev, Oleg V.
    Yunker, Mark B.
    Macdonald, Robie W.
    Wacker, Lukas
    Montlucon, Daniel B.
    Eglinton, Timothy I.
    Multimolecular tracers of terrestrial carbon transfer across the pan-Arctic: C-14 characteristics of sedimentary carbon components and their environmental controls2015Ingår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 29, nr 11, s. 1855-1873Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Distinguishing the sources, ages, and fate of various terrestrial organic carbon (OC) pools mobilized from heterogeneous Arctic landscapes is key to assessing climatic impacts on the fluvial release of carbon from permafrost. Through molecular C-14 measurements, including novel analyses of suberin- and/or cutin-derived diacids (DAs) and hydroxy fatty acids (FAs), we compared the radiocarbon characteristics of a comprehensive suite of terrestrial markers (including plant wax lipids, cutin, suberin, lignin, and hydroxy phenols) in the sedimentary particles from nine major arctic and subarctic rivers in order to establish a benchmark assessment of the mobilization patterns of terrestrial OC pools across the pan-Arctic. Terrestrial lipids, including suberin-derived longer-chain DAs (C-24,C-26,C-28), plant wax FAs (C(24,26,2)8), and n-alkanes (C-27,C-29,C-31), incorporated significant inputs of aged carbon, presumably from deeper soil horizons. Mobilization and translocation of these old terrestrial carbon components was dependent on nonlinear processes associated with permafrost distributions. By contrast, shorter-chain (C-16,C-18) DAs and lignin phenols (as well as hydroxy phenols in rivers outside eastern Eurasian Arctic) were much more enriched in C-14, suggesting incorporation of relatively young carbon supplied by runoff processes from recent vegetation debris and surface layers. Furthermore, the radiocarbon content of terrestrial markers is heavily influenced by specific OC sources and degradation status. Overall, multitracer molecular C-14 analysis sheds new light on the mobilization of terrestrial OC from arctic watersheds. Our findings of distinct ages for various terrestrial carbon components may aid in elucidating fate of different terrestrial OC pools in the face of increasing arctic permafrost thaw.

  • 230.
    Filipovic, Marko
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Fate of perfluoroalkyl acids in the aquatic environment with a focus on mass balance studies2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [sv]

    Perfluorerade alkylsyror (PFAA) är kemikalier som är producerade av människan. Deras unika egenskaper gör att de kan användas i många olika industriella applikationer. PFAAs används i brandsläckningsskum, vattenavvisande kläder, hydrauliska oljor och matförpackningar.

    PFAAs har visat sig vara persistenta i miljön, och långkedjiga PFAA-homologer har visat sig vara bioackumulerbara samt ha en toxisk verkan. Reglering på internationell nivå tillsammans med initiativ från industrin har lett till minskning av direkta utsläpp. Punktkällor som brandövningsplatser samt andra diffusa källor fortsätter att förorena omgivande vattendrag, jordlager och fauna. Den utbredda föroreningen av PFAAs har därför blivit prioriterad för reglering. För att förstå utsläppen av PFAAs i miljön, hur de transporteras samt deras öde i miljön, är det viktigt att utföra studier som belyser dessa områden.

     

    Denna doktorsavhandling inkluderar fyra vetenskapliga publikationer. Syftet med de underliggande studierna var att öka den holistiska förståelsen av PFAAs rörelse i akvatiska system. Studierna gjordes genom att kombinera kemiska analysmetoder med modellering. Följande  studier genomfördes; Transport och spridning av PFAAs från en brandövningsplats (Paper I), recyklering av PFAAs i den akvatiska miljön med fokus på vattenreningsverk (Paper II), massbalans av PFAAs i Östersjön (Paper III), transport och öde av PFAAs i två pristina vattendrag (Paper IV).

     

    Resultat från (Paper I) visade att brandövningsplatser vid en flygplats som inte har varit i bruk i mer än 30 år, fortfarande är punktkällor av PFAAs till omgivande vattendrag. Summan av PFAAs koncentrationer i grundvattnet och ytvattnet sträckte sig från 740 till 51000 ng L-1 och <0.5 till 79 ng L-1 i respektive vattendrag. Koncentrationen av PFOS i muskelvävnad från  aborre i en av sjöarna var 77 till 370 ng g-1 våtvikt. Dessa värden representerar några av de högsta uppmätta koncentrationerna i världen. I Paper II testades betydelsen av PFAAs från recirkulering i miljön i jämförelse med nya utsläpp från teknosfären. Recirkulering av PFAAs i miljön kan förekomma då PFAAs i inkommande vatten till reningsverk kommer från dricksvatten.

    Denna studie visar att dricksvatten kan vara en påtaglig källa av PFAAs till vattenreningsverk i områden med förhöjda halter av PFAAs i miljön. Detta måste tas hänsyn till när man beräknar emissioner med utgående vatten från vattenreningsverk. Massbalanser av PFAAs i reningsverken visar att PFHxA och PFOA bildades av prekursorämnen i vattenreningsverken. I Paper III beräknades massbalanserna av PFAAs i Östersjön, beräkningarna visar att floder och atmosfärisk nedebörd var de viktigaste källorna medan utsläppen från vattenreningsverk var markant lägre. Importen av PFAAs estimerades vara högre än exporten, varför vi tror att PFAAs mängden I Östersjön kommer att öka över tid. Vidare gjordes en mass balans av PFAAs i två avlägsna avrinningsområden (Paper IV). Resultaten visar att importen av PFAAs dominerar över exporten från båda avrinningsområdena. Detta indikerar att en stor del av PFAAs som kommer ner via nederbörd kommer att ansamlas i jorden eller i grundvattnet. Dessa PFAAs kan vid senare tillfälle komma att släppas ut till floder som rinner ut i marina vatten.

  • 231.
    Filipovic, Marko
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Laudon, Hjalmar
    McLachlan, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Berger, Urs
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mass Balance of Perfluorinated Alkyl Acids (PFAAs) in a Pristine Boreal CatchmentManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Mass balances of ten individual PFAAs in two nested pristine catchments in Northern Sweden with different sizes and hydrological functions were assembled for 2011-2012. Concentrations of PFAAs in rain and snowmelt, as well as in stream water at the outlet of the two watersheds were measured and used to calculate PFAA inputs and outputs to the catchments. The results generally showed a great excess of PFAA inputs for both catchments. During spring flow the stream water showed PFAA patterns resembling the patterns in rain (as opposed to snowmelt) and the mass balances were roughly closed for several PFAAs, suggesting that snowmelt water infiltrating the ground had displaced water from the previous summer. Comparison of PFAA mass balances between the two catchments further suggested that atmospheric inputs of short-chain (replacement) perfluoroalkyl carboxylic acids had increased in the years before sampling, while inputs of the legacy perfluorooctane sulfonic acid had decreased. The overall positive mass balances indicate that a considerable portion of the PFAAs deposited from the atmosphere are stored in soil and may be released to surface and marine water environments in the future.

  • 232.
    Filipovic, Marko
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Laudon, Hjalmar
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Berger, Urs
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Helmholtz Centre for Environmental Research—UFZ, Germany.
    Mass Balance of Perfluorinated Alkyl Acids in a Pristine Boreal Catchment2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 20, s. 12127-12135Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Mass balances of ten individual perfluorinated alkyl acids (PFAAs) in two nested pristine catchments in Northern Sweden with different sizes and hydrological functions were assembled for 2011-2012. Concentrations of PFAAs in rain and snowmelt, as well as in streamwater at the outlet of the two watersheds were measured and used to calculate PFAA atmospheric inputs to and riverine outputs from the catchments. The results generally showed a great excess of PFAA inputs for both catchments over the whole study year. However, during the spring flood period, the inputs and outputs were within a factor of 2 for several PFAAs and the streamwater showed PFAA patterns resembling the patterns in rain (as opposed to snowmelt), suggesting that snowmelt water infiltrating the ground had displaced water from the previous summer. Comparison of PFAA mass balances between the two catchments further suggested that atmospheric inputs of short-chain (replacement) perfluoroalkyl carboxylic acids had increased in the years before sampling, while inputs of the legacy perfluorooctane sulfonic acid had decreased. Overall, the mass balances indicate that a considerable portion of the PFAAs deposited from the atmosphere are stored in soil and may be released to surface and marine water environments in the future.

  • 233. Frank, Dorothe A.
    et al.
    Reichstein, Markus
    Bahn, Michael
    Thonicke, Kirsten
    Frank, David
    Mahecha, Miguel D.
    Smith, Pete
    Van der Velde, Marijn
    Vicca, Sara
    Babst, Flurin
    Beer, Christian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Max Planck Institute for Biogeochemistry, Jena, Germany.
    Buchmann, Nina
    Canadell, Josep G.
    Ciais, Philippe
    Cramer, Wolfgang
    Ibrom, Andreas
    Miglietta, Franco
    Poulter, Ben
    Rammig, Anja
    Seneviratne, Sonia I.
    Walz, Ariane
    Wattenbach, Martin
    Zavala, Miguel A.
    Zscheischler, Jakob
    Effects of climate extremes on the terrestrial carbon cycle: concepts, processes and potential future impacts2015Ingår i: Global Change Biology, ISSN 1354-1013, E-ISSN 1365-2486, Vol. 21, nr 8, s. 2861-2880Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Extreme droughts, heat waves, frosts, precipitation, wind storms and other climate extremes may impact the structure, composition and functioning of terrestrial ecosystems, and thus carbon cycling and its feedbacks to the climate system. Yet, the interconnected avenues through which climate extremes drive ecological and physiological processes and alter the carbon balance are poorly understood. Here, we review the literature on carbon cycle relevant responses of ecosystems to extreme climatic events. Given that impacts of climate extremes are considered disturbances, we assume the respective general disturbance-induced mechanisms and processes to also operate in an extreme context. The paucity of well-defined studies currently renders a quantitative meta-analysis impossible, but permits us to develop a deductive framework for identifying the main mechanisms (and coupling thereof) through which climate extremes may act on the carbon cycle. We find that ecosystem responses can exceed the duration of the climate impacts via lagged effects on the carbon cycle. The expected regional impacts of future climate extremes will depend on changes in the probability and severity of their occurrence, on the compound effects and timing of different climate extremes, and on the vulnerability of each land-cover type modulated by management. Although processes and sensitivities differ among biomes, based on expert opinion, we expect forests to exhibit the largest net effect of extremes due to their large carbon pools and fluxes, potentially large indirect and lagged impacts, and long recovery time to regain previous stocks. At the global scale, we presume that droughts have the strongest and most widespread effects on terrestrial carbon cycling. Comparing impacts of climate extremes identified via remote sensing vs. ground-based observational case studies reveals that many regions in the (sub-)tropics are understudied. Hence, regional investigations are needed to allow a global upscaling of the impacts of climate extremes on global carbon-climate feedbacks.

  • 234.
    Franke, Vera
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish University of Agricultural Sciences, Sweden.
    Zieger, Paul
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Wideqvist, Ulla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Acosta Navarro, Juan Camilo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Barcelona Supercomputing Center, Spain.
    Leck, Caroline
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Rosati, Bernadette
    Gysel, Martin
    Salter, Matthew Edward
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Chemical composition and source analysis of carbonaceous aerosol particles at a mountaintop site in central Sweden2017Ingår i: Tellus. Series B, Chemical and physical meteorology, ISSN 0280-6509, E-ISSN 1600-0889, Vol. 69, artikel-id 1353387Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The chemical composition of atmospheric particulate matter at Mt. angstrom reskutan, a mountaintop site in central Sweden, was analysed with a focus on its carbonaceous content. Filter samples taken during the Cloud and Aerosol Experiment at angstrom re (CAEsAR 2014) were analysed by means of a thermo-optical method and ion chromatography. Additionally, the particle light absorption and particle number size distribution measurements for the entire campaign were added to the analysis. Mean airborne concentrations of organic and elemental carbon during CAEsAR 2014 were OC= 0.85 +/- 0.8 mu gm(-3) and EC = 0.06 +/- 0.06 mu gm(-3), respectively. Elemental to organic carbon ratios varied between EC/OC = 0.02 and 0.19. During the study a large wildfire occurred in Vastmanland, Sweden, with the plume reaching our study site. This led to significant increases in OC and EC concentrations (OC = 3.04 +/- 0.03 mu gm(-3) and EC = 0.24 +/- 0.00 mu gm(-3)). The mean mass-specific absorption coefficient observed during the campaign was sigma(BC)(abs) = 9.1 +/- 7.3 m(2)g(-1) (at wavelength lambda= 637 nm). In comparison to similarly remote European sites, Mt. angstrom reskutan experienced significantly lower carbonaceous aerosol loadings with a clear dominance of organic carbon. A mass closure study revealed a missing chemical mass fraction that likely originated from mineral dust. Potential regional source contributions of the carbonaceous aerosol were investigated using modelled air mass back trajectories. This source apportionment pointed to a correlation between high EC concentrations and air originating from continental Europe. Particles rich in organic carbon most often arrived from highly vegetated continental areas. However, marine regions were also a source of these aerosol particles. The source contributions derived during this study were compared to emission inventories of an Earth system model. This comparison highlighted a lack of OC and EC point-sources in the model's emission inventory which could potentially lead to an underestimation of the carbonaceous aerosol reaching Mt. angstrom reskutan in the simulation of this Earth system model.

  • 235.
    Freud, Eyal
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Leaitch, Richard
    Nguyen, Quynh T.
    Massling, Andreas
    Skov, Henrik
    Barrie, Leonard
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Pan-Arctic aerosol number size distributions: seasonality and transport patterns2017Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 17, nr 13, s. 8101-8128Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic environment has an amplified response to global climatic change. It is sensitive to human activities that mostly take place elsewhere. For this study, a multi-year set of observed aerosol number size distributions in the diameter range of 10 to 500 nm from five sites around the Arctic Ocean (Alert, Villum Research Station - Station Nord, Zeppelin, Tiksi and Barrow) was assembled and analysed. A cluster analysis of the aerosol number size distributions revealed four distinct distributions. Together with Lagrangian air parcel back-trajectories, they were used to link the observed aerosol number size distributions with a variety of transport regimes. This analysis yields insight into aerosol dynamics, transport and removal processes, on both an intra- and an inter-monthly scale. For instance, the relative occurrence of aerosol number size distributions that indicate new particle formation (NPF) event is near zero during the dark months, increases gradually to similar to 40% from spring to summer, and then collapses in autumn. Also, the likelihood of Arctic haze aerosols is minimal in summer and peaks in April at all sites. The residence time of accumulation-mode particles in the Arctic troposphere is typically long enough to allow tracking them back to their source regions. Air flow that passes at low altitude over central Siberia and western Russia is associated with relatively high concentrations of accumulation-mode particles (N-acc) at all five sites - often above 150 cm(-3). There are also indications of air descending into the Arctic boundary layer after transport from lower latitudes. The analysis of the back-trajectories together with the meteorological fields along them indicates that the main driver of the Arctic annual cycle of N-acc, on the larger scale, is when atmospheric transport covers the source regions for these particles in the 10-day period preceding the observations in the Arctic. The scavenging of these particles by precipitation is shown to be important on a regional scale and it is most active in summer. Cloud processing is an additional factor that enhances the N-acc annual cycle. There are some consistent differences between the sites that are beyond the year-to-year variability. They are the result of differences in the proximity to the aerosol source regions and to the Arctic Ocean sea-ice edge, as well as in the exposure to free-tropospheric air and in precipitation patterns - to mention a few. Hence, for most purposes, aerosol observations from a single Arctic site cannot represent the entire Arctic region. Therefore, the results presented here are a powerful observational benchmark for evaluation of detailed climate and air chemistry modelling studies of aerosols throughout the vast Arctic region.

  • 236. Fuchslueger, Lucia
    et al.
    Wild, Birgit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Vienna, Austria.
    Mooshammer, Maria
    Takriti, Mounir
    Kienzl, Sandra
    Knoltsch, Anna
    Hofhansl, Florian
    Bahn, Michael
    Richter, Andreas
    Microbial carbon and nitrogen cycling responses to drought and temperature in differently managed mountain grasslands2019Ingår i: Soil Biology and Biochemistry, ISSN 0038-0717, E-ISSN 1879-3428, Vol. 135, s. 144-153Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Grassland management can modify soil microbial carbon (C) and nitrogen (N) cycling, affecting the resistance to extreme weather events, which are predicted to increase in frequency and magnitude in the near future. However, effects of grassland management on microbial C and N cycling and their responses to extreme weather events, such as droughts and heatwaves, have rarely been tested in a combined approach. We therefore investigated whether grassland management affects microbial C and N cycling responses to drought and temperature manipulation. We collected soils from in situ drought experiments conducted in an extensively managed and an abandoned mountain grassland and incubated them at two temperature levels. We measured microbial respiration and substrate incorporation, as well as gross rates of organic and inorganic N cycling to estimate microbial C and N use efficiencies (CUE and NUE). The managed grassland was characterized by lower microbial biomass, lower fungi to bacteria ratio, and higher microbial CUE, but only slightly different microbial NUE. At both sites drought induced a shift in microbial community composition driven by an increase in Gram-positive bacterial abundance. Drought significantly reduced C substrate respiration and incorporation by microbes at both sites, while microbial CUE remained constant. In contrast, drought increased gross rates of N mineralization at both sites, whereas gross amino acid uptake rates only marginally changed. We observed a significant direct, as well as interactive effect between land management and drought on microbial NUE. Increased temperatures significantly stimulated microbial respiration and reduced microbial CUE independent of drought or land management. Although microbial N processing rates showed no clear response, microbial NUE significantly decreased at higher temperatures. In summary in our study, microbial CUE, in particular respiration, is more responsive to temperature changes. Although N processing rates were stronger responding to drought than to temperature microbial NUE was affected by both drought and temperature increase. We conclude that direct effects of drought and heatwaves can induce different responses in soil microbial C and N cycling similarly in the studied land management systems.

  • 237.
    Furuhagen, Sara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholm University.
    Application and interpretation of biomarkers in ecotoxicology - from molecular to individual level responses2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The use of biomarkers is considered a promising alternative, or complement, to traditional ecotoxicological assays. Toxic effects are often initially manifested at the molecular or biochemical level, biomarkers are therefore used as sensitive indicators of toxic exposure. Ideally, biomarkers would also indicate reduced fitness and possible later effects at the individual or population levels. However, implementing biomarkers in ecotoxicology is challenging and few biomarkers have an established connection to reduced individual fitness. The aim of this thesis was to increase the value and improve the interpretation of biomarker responses in ecotoxicological studies by examining the impact of confounding factors and the relationship between oxidative biomarkers and reproductive effects in crustaceans.

    The sensitivity of biomarkers was confirmed in paper I as toxic effects of pharmaceuticals with conserved drug target orthologs were observed at the molecular and biochemical levels both earlier and at lower concentrations than effects on mortality and reproduction. No toxic effects were observed for the pharmaceutical without identified drug target orthologs, thus stressing the importance of considering toxic mechanisms and being aware of the most likely target when evaluating toxic effects also in non-target species. Many xenobiotics and environmental stressors interfere with oxidative processes, making oxidative biomarkers interesting to study in ecotoxicology and stress ecology. Still, feeding rate was identified as a confounding factor for antioxidant capacity (assayed as oxygen radical absorbance capacity, ORAC) and lipid peroxidation in ecotoxicological studies (paper II). However, ORAC normalized to protein was independent of altered feeding rates, hence it can be applied as a suitable exposure biomarker without considering alterations and effects of feeding rate. The connection between reproduction and oxidative stress is dual, as reproduction both can be inhibited by oxidative stress and induce pro-oxidative processes. Further, a positive association was found between ORAC and the occurrence of embryo aberrations in the benthic amphipod Monoporeia affinis (paper III). An association between antioxidant defense and reproduction was also observed for Daphnia magna (paper IV). Threshold values for identification of exposed individuals and prediction of possible later reproductive effects were established for ORAC.

    This thesis has contributed to diminishing some of the knowledge gaps limiting the use of oxidative biomarkers in ecotoxicology, by contributing to increased understanding of how oxidative biomarkers relate to important life-traits. Moreover, ORAC has been identified as a suitable biomarker of not only exposure, but also reproductive effects. Future research should continue to establish connections between biomarker responses and effects at higher levels, and focus on providing defined threshold values to enable predictions about later effects.   

  • 238.
    Furuhagen, Sara
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Liewenborg, Birgitta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Breitholtz, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Oxidative biomarkers as indicators of reproductive effects in Daphnia magnaManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Oxidative stress can be induced by various stressors, and oxidative biomarkers are commonly used as indicators of xenobiotic exposure. However, the capacity of oxidative biomarkers to predict pro-oxidative exposure or indicate reproductive effects has not been evaluated. In this study, we hypothesized that biomarkers of oxidative stress (catalase, antioxidant capacity, and lipid peroxidation) can be used to diagnose pro-oxidative exposure, with concomitant reproductive penalties. We exposed Daphnia magna to UVB irradiation, a known agent inducing pro-oxidative processes in various organisms, from birth to adult stage. The biomarker responses were followed in different life-stages in concert with reproductive success and individual growth rate. The UVB exposure induced alterations in antioxidant capacity (measured as oxygen radical absorbance capacity, ORAC) in both juvenile and adult daphnids. Moreover, these effects were age-specific, with decreased and increased ORAC in juveniles and adults, respectively. These changes were associated with reproductive success, as increased number of offspring was negatively associated with antioxidant capacity. Also, a trans-generational effect was observed as exposed females allocated less antioxidants to their offspring. ORAC normalized to protein content (ORACp) was identified as a suitable biomarker of pro-oxidative exposure. For diagnostics of oxidative stress in field and laboratory settings, two logistic models employing ORACp in juvenile and adult D. magna were proposed; the classification accuracy of the models was about 80%. None of the other biomarkers contributed significantly to the models.

  • 239.
    Fyrestam, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Escherichia coli is killed by 405 nm blue light due to its endogenous porphyrins induced by 5-aminolevulinic acidManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Antimicrobial phototherapy without the use of an exogenous photosensitizer has been suggested to be a complement to antibiotics.  A commonly accepted hypothesis is that bacteria are producing endogenous porphyrins that may act as photosensitizers. To our best knowledge there are no studies linking the production of singlet oxygen for naturally occurring porphyrins to the bacterial porphyrin content, and the photosensitivity of bacteria. In the present study, we determined the quantum yield of singlet oxygen for three porphyrins commonly detected in bacteria. Porphyrin content in E. coli was determined by HPLC-MS/MS before and after administration of 5-aminolaevulinic acid (5-ALA) to the cultivation broth. 5-aminolaevulinic acid is a porphyrin precursor and will induce high amounts of intracellular porphyrins. Cultures of E. coli grown with and without 5-ALA were illuminated with 405 nm light at different light doses. Relative to the amount, uroporphyrin demonstrated the highest quantum yield of singlet oxygen, followed by coproporphyrin and protoporphyrin IX. E. coli was analyzed for porphyrin content and only low amounts of coproporphyrin I, coproporphyrin III and protoporphyrin IX could be detected. In addition, E. coli showed no sensitivity for 405 nm light at the highest dose (172.8 J/cm2). However, when E. coli was grown in 5 mM 5-ALA for 48 h, the intracellular content of porphyrins increased remarkably. Uroporphyrin was the most abundant porphyrin with 48% of total porphyrin content. Addition of 5-ALA also made E. coli more sensitive for blue light. A light dose of 4.8 J/cm2 reduced viable E. coli with 3 log10 steps and at a light dose of 57.6 J/cm2 the killing efficiency was higher than the level to work as an disinfectant (>5 log10 steps). These results shows that E. coli is be killed by light due to its endogenously produced porphyrins and that uroporphyrin could play an important part in these mechanisms.  

  • 240.
    Fyrestam, Jonas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Porphyrins and heme in microorganisms: Porphyrin content and its relation to phototherapy and antimicrobial treatments in vivo and in vitro2017Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    One of the greatest threats to human health is increasing antimicrobial resistance among pathogens, and finding alternatives for treatment of bacterial infections is of highest importance together with a more controlled use of antibiotics. Porphyrins and heme have both been shown to be a promising class of compounds for inactivation of bacteria; porphyrins by their excellent properties to act as a photosensitizer, and heme by its importance as an iron source during a bacterial infection in vertebrates.

    This thesis describes the development of analytical methods for the identification and determination of porphyrins and heme using liquid chromatography coupled to tandem mass spectrometry. Subsequently, these developed methods were applied to bacterial samples to investigate different culture conditions and additives effect to the intracellular porphyrin and heme composition. Singlet oxygen production of three naturally occurring porphyrins have been determined together with the photosensitivity for blue light and the porphyrin content in E. coli. Toothbrushes equipped with a LED, emitting light with a wavelength of 450 nm, were used in an eight week randomized clinical trial to investigate any positive periodontal effect of blue light.

    Porphyrin and heme content in Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis were highly affected by the different cultivation conditions. The culture age of A. actinomycetemcomitans affected the porphyrin profile, while only small changes were observed for P. gingivalis during growth. A large change of the porphyrin profile could be observed when the bacteria were passaged onto a new growth medium. Additional porphyrins were detected and the total porphyrin content increased up to 28 times. These findings highlight the need for more standardized cultivation procedures when performing in vitro experiments.

    Heme content in Escherichia coli was affected when different additives related to biosynthesis of heme were added to the growth medium. The uptake of heme could be reduced with 52% when a compound that chemically looks similar to heme was added to the growth medium. Since heme acquisition is important for many pathogens, this could be a promising target for antimicrobial drugs.

    E. coli showed no sensitivity for 405 nm light using light doses up to 172.8 J/cm2 and only low concentrations of porphyrins could be quantified. By adding a porphyrin precursor to E. coli the intracellular concentration of porphyrins increased remarkably and a light dose of 57.6 J/cm2 reduced the bacterial number with > 5 log10 steps. This shows that E. coli can be killed due to their endogenous porphyrins.

    In the clinical study we could see a weak trend that the 450 nm LED toothbrush possessed a phototherapeutic effect for three clinical indices. All indices were decreased in the intervention group, but there were no statistically significant difference compared to the control group. However, four inflammation markers were significantly decreased in the intervention group while only one decreased significantly in the control group.

    In conclusion, this thesis has shown that porphyrins and heme are produced endogenously in microorganisms and that the porphyrin profiles vary depending on culture conditions and different additives. Furthermore, porphyrins may be used as endogenous photosensitizers to inactivate bacteria, but more research is necessary to determine if there is a specific porphyrin that contributes more to the photosensitivity.

  • 241.
    Fyrestam, Jonas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bjurshammar, Nadja
    Paulsson, Elin
    Johannsen, Annsofi
    Östman, Conny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Determination of porphyrins in oral bacteria by liquid chromatography electrospray ionization tandem mass spectrometry2015Ingår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 407, nr 23, s. 7013-7023Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biofilms in the oral cavity can be visualized by fluorescence and a common assumption is that the endogenously produced porphyrins in certain bacteria give rise to this fluorescence. Porphyrin content in oral bacteria has been sparingly investigated, and non-selective detection techniques such as utilizing the Soret fluorescence band of porphyrins are often used. In the present study, a quantitative and selective method for the determination of porphyrins in oral bacteria has been developed and validated using high performance liquid chromatography-tandem mass spectrometry. Lysis of bacteria using Tris-EDTA buffer together with ultrasonication showed high microbial killing efficiency ≥99.98 %, and sample clean-up using C18-solid phase extraction resulted in low matrix effects ≤14 % for all analytes. Using this method, the porphyrin content was determined in the two oral pathogens Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis, as well as for baker’s yeast, Saccharomyces cerevisiae. Uroporphyrin, 7-carboxylporphyrin, 6-carboxylporphyrin, coproporphyrin, and protoporphyrin IX were identified in the investigated microorganisms, and it was shown that the porphyrin profile differs between the two bacteria, as well as for S. cerevisiae. To our knowledge, this is the first time the porphyrin profile has been determined for the bacterium A. actinomycetemcomitans.

  • 242.
    Fyrestam, Jonas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bjurshammar, Nadja
    Paulsson, Elin
    Mansouri, Nesrine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Johannsen, Annsofi
    Östman, Conny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Influence of culture conditions on porphyrin production in Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis2017Ingår i: Photodiagnosis and Photodynamic Therapy, ISSN 1572-1000, E-ISSN 1873-1597, Vol. 17, s. 115-123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Increasing antibiotic resistance among pathogens has raised the demands for new treatment methods such as antimicrobial photodynamic therapy (aPDT) and phototherapy (PT). Experiments for investigating the effects of these methods are often performed in vitro, but the procedures for cultivation of microbes vary between different studies. The aim of this study has been to elucidate how the profile of endogenously produced porphyrins differs by changing the variables of bacteria culturing conditions.

    Methods: Two oral pathogens, Aggregatibacter actinomycetemcomitans and Porphyromonasgingivalis, were selected as model organisms. The contents of porphyrins and heme in the bacteria were analysed with liquid chromatography-tandem mass spectrometry when bacteria was cultivated for different lengths of time (3-9 days), upon passaging as well as when growth medium were supplemented with or without horse blood.

    Results: Both porphyrin and heme content in A. actinomycetemcomitans are highly affected by the age of the culture, and that the porphyrin profiles changes during cultivation. When cultivated colonies of A. actinomycetemcomitans were passaged onto a new, fresh growth medium a large change in porphyrin content occurred. Additional porphyrins were detected; uroporphyrin and 7-carboxylporphyrin, and the total porphyrin content increased up to 28 times, When P. gingivalis was grown on blood containing medium higher concentrations of protoporphyrin IX (2.5 times) and heme (5.4 times) were quantified compared to bacteria grown without blood.

    Conclusions: This study demonstrate that there is a need for more standardized culturing protocols when performing aPDT and PT experiments in vitro to avoid large variations in porphyrin profiles and concentrations, the aPDT/PT target compounds, depending on the culturing conditions.

  • 243.
    Fyrestam, Jonas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Östman, Conny
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Determination of heme in microorganisms using HPLC-MS/MS and cobalt(III) protoporphyrin IX inhibition of heme acquisition in Escherichia coli2017Ingår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 409, nr 30, s. 6999-7010Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    One of the main threats to the achievements in modern medicine is antimicrobial resistance. Molecular targeting of bacterial acquisition mechanisms of heme has been suggested to be an alternative to antibiotics. In the present study, HPLC-MS/MS combined with a simple clean-up based on liquid-liquid extraction has been developed and evaluated for simultaneous determination of heme and porphyrin heme precursors in microorganisms. Experimental design was used to optimize the extraction parameters, to obtain a method with high recovery, low matrix effects, and high precision. The effects of additives in the culture medium on the biosynthesis of heme were studied using Escherichia coli as a model microorganism. 5-Aminolaevulinic acid and hemin increased the heme concentration in E. coli by a factor of 1.5 and 4.5, respectively. Addition of 5-aminolaevulinic acid bypassed the E. coli negative feedback control of heme biosynthesis, which led to high amounts of intracellular porphyrins. The high heme concentration obtained when hemin was used as a culture additive shows that E. coli has an uptake of heme from its surroundings. In contrast, addition of cobalt protoporphyrin IX to the growth medium reduced the amount of heme in E. coli, demonstrating this compound’s ability to mimic real heme and inhibit the heme acquisition mechanisms.

  • 244.
    Fång, Johan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish Museum of Natural History, Sweden.
    Nyberg, Elisabeth
    Swedish Museum of Natural History, Sweden.
    Winnberg, Ulrika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Swedish Museum of Natural History, Sweden.
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish Toxicology Sciences Research Center (Swetox), Sweden.
    Spatial and temporal trends of the Stockholm Convention POPs in mothers' milk - a global review2015Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 22, nr 12, s. 8989-9041Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Persistent organic pollutants (POPs) have been of environmental and health concern for more than half a century and have their own intergovernmental regulation through the Stockholm Convention, from 2001. One major concern is the nursing child's exposure to POPs, a concern that has led to a very large number of scientific studies on POPs in mothers' milk. The present review is a report on the assessment on worldwide spatial distributions of POPs and of their temporal trends. The data presented herein is a compilation based on scientific publications between 1995 and 2011. It is evident that the concentrations in mothers' milk depend on the use of pesticides and industrial chemicals defined as POPs. Polychlorinated biphenyls (PCBs) and dioxins are higher in the more industrialized areas, Europe and Northern America, whereas pesticides are higher in Africa and Asia and polybrominated diphenyl ethers (PBDEs) are reported in higher concentrations in the USA. POPs are consequently distributed to women in all parts of the world and are thus delivered to the nursing child. The review points out several major problems in the reporting of data, which are crucial to enable high quality comparisons. Even though the data set is large, the comparability is hampered by differences in reporting. In conclusion, much more detailed instructions are needed for reporting POPs in mothers' milk. Temporal trend data for POPs in mothers' milk is scarce and is of interest when studying longer time series. The only two countries with long temporal trend studies are Japan and Sweden. In most cases, the trends show decreasing concentrations of POPs in mothers' milk. However, hexabromocyclododecane is showing increasing temporal concentration trends in both Japan and Sweden.

  • 245.
    Gamal Ramzi, Ahmed
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Analytical methodologies for common skin allergens: Organic thioureas, isothiocyanates and fragrance hydroperoxides in everyday life products2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis describes analytical methodologies for the determination of important skin-sensitizing chemicals in two types of commercial items: chloroprene rubber and fragrance products which are both well-known to be associated with contact allergy.

    Chloroprene rubber (neoprene) is widely used in different applications and products, such as bags, gloves, wetsuits, braces, mouse pads et c. Exposure to chloroprene rubber materials has resulted in numerous cases of allergic contact dermatitis. Organic thioureas have been considered the main culprits, even though they at the same time have been classified as weak or non-sensitizers in the murine local lymph node assay (LLNA). Previous findings indicate that a possible reason for sensitization is that organic thioureas are being metabolized in the skin into more reactive electrophiles, such as isothiocyanates and isocyanates, after skin exposure. In this thesis, chemical analyses of a number of chloroprene products from the European open market showed the presence of diethylthiourea in all analyzed items, while other organic thioureas could not be detected. The levels of diethylthiourea varied, with the highest at 158 µg cm-2 in a used back support that had previously caused allergic contact dermatitis in a patient. Furthermore, it was discovered that all the examined items emitted ethyl isothiocyanate. LLNA showed that ethyl isothiocyanate is a strong skin sensitizer, as has been shown earlier for other tested isothiocyanates. Isothiocyanates were shown to be thermally formed from diethyl, diphenyl and dibutylthiourea at a temperature as low as 35 °C, i. e. around skin temperature. Altogether, the results from these experiments, patch tests and chemical analyses revealed that isothiocyanates are important haptens in contact allergy to chloroprene rubber.

    Fragrances constitute one of the main causes of contact allergy, next to nickel and preservatives. The most widespread fragrances in cosmetics and perfumes on the market are monoterpenes, such as linalool and limonene, which at air exposure easily oxidize to hydroperoxides, which are strongly skin sensitizing compounds and the main haptens. Despite this, there is so far no EU regulation concerning fragrance hydroperoxides in products, which may be due to lack of analytical methods which can reliably measure them in fragrances. Presented in this thesis is a toolbox of different analytical methods, applied on essential oils, shampoo, patch test preparations and different types of perfumes. Furthermore, one of our studies elucidated the first case (to my knowledge) of allergic contact dermatitis as being correlated to a product that contains a fragrance hydroperoxide.

    Taken together, the thesis shows the importance of developing analytical methods for the identification, measurement and detection of important haptens in contact allergy. 

  • 246. Gawhane, R. D.
    et al.
    Rao, P. S. P.
    Budhavant, Krishnakant
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Meshram, D. C.
    Safai, P. D.
    Anthropogenic fine aerosols dominate over the Pune region, Southwest India2019Ingår i: Meteorology and atmospheric physics (Print), ISSN 0177-7971, E-ISSN 1436-5065, Vol. 131, nr 5, s. 1497-1508Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The major water-soluble ions, organic carbon (OC), elemental carbon (EC) and mass concentration of fine- (PM2.5) and coarse-mode (PM10-2.5) aerosols were measured at Pune during January-December 2016. The mass closure approach was used by comparing the sum of the masses of the individual chemical species to the gravimetric PM obtained by weighting the filter samples. The 1 year mean total mass concentration of fine and coarse mode was 40 mu gm(-3) (64%) and 23 mu g m(-3) (36%), respectively. The PM2.5/PM10 ratio was 0.64 +/- 0.9 indicating an abundance of fine-mode particles over Pune during the study period. A principal component analysis identified three components, where the one with highest explanatory power (59%) displayed clear impact of anthropogenic sources on the measured mass concentration of a majority of the compounds. The strong linear relationships between EC, OC, nss-SO42- and nss-K+ suggest a predominance of a common primary source, with a contribution from biofuel as well as biomass burning sources. Keeping the strong correlation and sources of individual chemical species as the base, it was noticed that (1) major contributors to fine- and coarse-mode particles over the Pune regions are carbonaceous aerosols and secondary inorganic aerosols (non-sea-salt SO42-, NO3-, and NH4+), (2) anthropogenic aerosols contribute mostly to the fine-mode, and (3) meteorological parameters play an important role in controlling levels of fine- and coarse-mode particles. Taken together, the study clearly indicates the dominance of anthropogenic sources during the entire year with more significance in the winter season.

  • 247. Ge, Linke
    et al.
    Dong, Qianqian
    Halsall, Crispin
    Chen, Chang-Er L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Li, Jun
    Wang, Degao
    Zhang, Peng
    Yao, Ziwei
    Aqueous multivariate phototransformation kinetics of dissociated tetracycline: implications for the photochemical fate in surface waters2018Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 25, nr 16, s. 15726-15732Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Antibiotics are ubiquitous pollutants in aquatic systems and can exist as different dissociated species depending on the water pH. New knowledge of their multivariate photochemical behavior (i.e., the photobehavior of different ionized forms) is needed to improve our understanding on the fate and possible remediation of these pharmaceuticals in surface and waste waters. In this study, the photochemical degradation of aqueous tetracycline (TC) and its dissociated forms (TCH20, TCH-, and TC2-) was investigated. Simulated sunlight experiments and matrix calculations indicated that the three dissociated species had dissimilar photolytic kinetics and photo-oxidation reactivities. TC2- photo-degraded the fastest due to apparent photolysis with a kinetic constant of 0.938 +/- 0.021 min(-1), followed by TCH- (0.020 +/- 0.005 min(-1)) and TCH20 (0.012 +/- 0.001 min(-1)), whereas Tar was found to be the most highly reactive toward center dot OH (105.78 +/- 3.40 M(-1 )s(-1)), and TC2- reacted the fastest with O-1(2) (344.96 +/- 45.07 M-1 s(-1)). Water with relatively high pH (e.g., similar to 8-9) favors the dissociated forms of TCH- and TC2- which are most susceptible to photochemical loss processes compared to neutral TC. The calculated corresponding environmental half-lives (t(1/2,E) ) in sunlit surface waters ranged from 0.05 h for pH = 9 in midsummer to 3.68 h for pH = 6 in midwinter at 45 degrees N latitude. The moms was dominated by apparent photolysis (especially in summer, 62-91%), followed by O-1(2) and center dot OH oxidation. Adjusting the pH to slightly alkaline conditions prior to UV or solar UV light treatment may be an effective way of enhancing the photochemical removal of TC from contaminated water.

  • 248.
    Gebbink, Wouter A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Berger, Urs
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Helmholtz Centre for Environmental Research − UFZ, Germany.
    Perfluoroalkyl Acids (PFAAs) and Selected Precursors in the Baltic Sea Environment: Do Precursors Play a Role in Food Web Accumulation of PFAAs?2016Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 50, nr 12, s. 6354-6362Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present study examined the presence of perfluoroalkyl acids (PFAAs) and selected precursors in the Baltic Sea abiotic environment and guillemot food web, and investigated the relative importance of precursors in food web accumulation of PFAAs. Sediment, water, zooplankton, herring, sprat, and guillemot eggs were analyzed for perfluoroalkane sulfonic acids (PFSAs; C-4,C-6,C-8,C-10) and perfluoroalkyl carboxylic acids (PFCAs; C6-15) along with six perfluorooctane sulfonic acid (PFOS) precursors and 11 polyfluoroalkyl phosphoric acid diesters (diPAPs). FOSA, FOSAA. and its methyl and ethyl derivatives (Me- and EtFOSAA), and 6:2/6:2 diPAP were detected in sediment and water. While FOSA and the three FOSAAs were detected in all biota, a total of nine diPAPs were only detected in zooplankton. Concentrations of PFOS precursors and diPAPs exceeded PFOS and PFCA concentrations, respectively, in zooplankton, but not in fish and guillemot eggs. Although PFOS precursors were present at all trophic levels, they appear to play a minor role in food web accumulation of PFOS based on PFOS precursor/PFOS ratios and PFOS and FOSA isomer patterns. The PFCA pattern in fish could not be explained by the intake pattern based on PFCAs and analyzed precursors, that is, diPAPs. Exposure to additional precursors might therefore be a dominant exposure pathway compared to direct PFCA exposure for fish.

  • 249.
    Gebbink, Wouter A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bossi, Rossana
    Rigét, Frank F.
    Rosing-Asvid, Aqqalu
    Sonne, Christian
    Dietz, Rune
    Observation of emerging per- and polyfluoroalkyl substances (PFASs) in Greenland marine mammals2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 144, s. 2384-2391Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The present pilot study examined emerging per- and polyfluoroalkyl substances (PFASs), i.e., a suite of short chain perfluoroalkyl acids (PFAAs), PFAA precursors and replacement chemicals, and legacy PFASs (long chain length PFAAs) in livers from ringed seals, polar bears and, for the first time, killer whales from East Greenland collected in 2012-2013. Among the emerging PFASs, perfluorobutanesulfonic acid (PFBS) and F-53B (a chlorinated polyfluorinated ether sulfonic acid) were detected in Arctic wildlife, albeit at concentrations approximately four orders of magnitude lower compared to perfluorooctanesulfonic acid (PFOS). PFOS was positively correlated with F-53B, but not PFBS in all three species. A total of 17 PFASs were detected in killer whales, including in a mother-fetus pair, demonstrating maternal transfer. Sigma PFAS concentrations in killer whales (269 +/- 90 ng/g) were comparable to concentrations found in ringed seals (138 +/- 7 ng/g), however, an order of magnitude lower compared to concentrations found in polar bear livers (2336 +/- 263 ng/g). Patterns of long chain PFAAs in killer whales differed from the pattern in ringed seals and polar bears. Of the monitored PFAA precursors, only perfluorooctanesulfonamide (FOSA) was detected in all three species, and FOSA/PFOS ratios and isomer patterns indicated that killer whales have a potential lower metabolic capacity to degrade FOSA compared to polar bears and ringed seals.

  • 250.
    Gebbink, Wouter A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Glynn, Anders
    Berger, Urs
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Temporal changes (1997-2012) of perfluoroalkyl acids and selected precursors (including isomers) in Swedish human serum2015Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 199, s. 166-173Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Concentrations (including isomer patterns) and temporal changes (1997-2012) of perfluoroalkyl acids (PFAAs) and selected perfluorooctane sulfonate (PFOS) and perfluoroalkyl carboxylic acid (PFCA) precursors were determined in serum samples from Swedish women. Perfluorooctane sulfonamide (FOSA) and perfluorooctane sulfonamidoacetic acid (FOSAA), as well as its N-methyl and N-ethyl derivatives (MeFOSAA and EtFOSAA) were consistently detected. Highest PFOS precursor concentrations were found for EtFOSAA (before year 2000) or MeFOSAA and FOSAA (after 2000). Disappearance half-lives for all PFOS precursors were shorter compared to PFOS. 4:2/6:2 and 6:2/6:2 polyfluoroalkyl phosphate diesters (diPAPs) were detected in <60% of the samples, whereas 6:2/8:2 and 8:2/8:2 diPAPs were detected in >60% of the samples, but showed no significant change in concentrations over time. Linear and sumbranched isomers were quantified separately for three PFAAs and three precursors. Significant changes between 1997 and 2012 in the % linear isomer were observed for PFOA and FOSA (increase) and PFOS (decrease).

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