Change search
Refine search result
12131415 701 - 724 of 724
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 701. Zhang, Jin
    et al.
    Kamstra, Jorke H.
    Ghorbanzadeh, Mehdi
    Weiss, Jana M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. VU University Amsterdam, The Netherlands.
    Hamers, Timo
    Andersson, Patrik L.
    In Silico Approach To Identify Potential Thyroid Hormone Disruptors among Currently Known Dust Contaminants and Their Metabolites2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 16, p. 10099-10107Article in journal (Refereed)
    Abstract [en]

    Thyroid hormone disrupting chemicals (THDCs) interfere with the thyroid hormone system and may induce multiple severe physiological disorders. Indoor dust ingestion is a major route of THDCs exposure in humans, and one of the molecular targets of these chemicals is the hormone transporter transthyretin (TTR). To virtually screen indoor dust contaminants and their metabolites for THDCs targeting TTR, we developed a quantitative structure activity relationship (QSAR) classification model. The QSAR model was applied to an in-house database including 485 organic dust contaminants reported from literature data and their 433 in silico derived metabolites. The model predicted 37 (7.6%) dust contaminants and 230 (53.1%) metabolites as potential TTR binders. Four new THDCs were identified after testing 23 selected parent dust contaminants in a radio-ligand TTR binding assay; 2,2',4,4'-tetrahydroxybenzophenone, perfluoroheptanesulfonic acid, 3,5,6-trichloro-2-pyridinol, and 2,4,5-trichlorophenoxyacetic acid. These chemicals competitively bind to TTR with 50% inhibition (IC50) values at or below 10 mu M. Molecular docking studies suggested that these THDCs interacted similarly with TTR via the residue Ser117A, but their binding poses were dissimilar to the endogenous ligand T4. This study identified new THDCs using an in silico approach in combination with bioassay testing and highlighted the importance of metabolic activation for TTR binding.

  • 702. Zhang, Shipeng
    et al.
    Wang, Minghuai
    Ghan, Steven J.
    Ding, Aijun
    Wang, Hailong
    Zhang, Kai
    Neubauer, David
    Lohmann, Ulrike
    Ferrachat, Sylvaine
    Takeamura, Toshihiko
    Gettelman, Andrew
    Morrison, Hugh
    Lee, Yunha
    Shindell, Drew T.
    Partridge, Daniel G.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Oxford, UK.
    Stier, Philip
    Kipling, Zak
    Fu, Congbin
    On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 5, p. 2765-2783Article in journal (Refereed)
    Abstract [en]

    Aerosol-cloud interactions continue to constitute a major source of uncertainty for the estimate of climate radiative forcing. The variation of aerosol indirect effects (AIE) in climate models is investigated across different dynamical regimes, determined by monthly mean 500 hPa vertical pressure velocity (omega(500)), lower-tropospheric stability (LTS) and large-scale surface precipitation rate derived from several global climate models (GCMs), with a focus on liquid water path (LWP) response to cloud condensation nuclei (CCN) concentrations. The LWP sensitivity to aerosol perturbation within dynamic regimes is found to exhibit a large spread among these GCMs. It is in regimes of strong large-scale ascent (omega(500)aEuro-aEuro parts per thousand < aEuro-a'25 hPa day(-1)) and low clouds (stratocumulus and trade wind cumulus) where the models differ most. Shortwave aerosol indirect forcing is also found to differ significantly among different regimes. Shortwave aerosol indirect forcing in ascending regimes is close to that in subsidence regimes, which indicates that regimes with strong large-scale ascent are as important as stratocumulus regimes in studying AIE. It is further shown that shortwave aerosol indirect forcing over regions with high monthly large-scale surface precipitation rate (> 0.1 mm day(-1)) contributes the most to the total aerosol indirect forcing (from 64 to nearly 100 %). Results show that the uncertainty in AIE is even larger within specific dynamical regimes compared to the uncertainty in its global mean values, pointing to the need to reduce the uncertainty in AIE in different dynamical regimes.

  • 703.
    Zhou, Yihui
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Athanassiadis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Wideqvist, Ulla
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bignert, Anders
    Qiu, Yanling
    Zhu, Zhiliang
    Zhao, Jianfu
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish Toxicology Sciences Research Center (Swetox), Sweden; Tongji University, China.
    Extensive organohalogen contamination in wildlife from a site in the Yangtze River Delta2016In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 554, p. 320-328Article in journal (Refereed)
    Abstract [en]

    The environmental and human health concerns for organohalogen contaminants (OHCs) extend beyond the 23 persistent organic pollutants (POPs) regulated by the Stockholm Convention. The current, intense industrial production and use of chemicals in China and their bioaccumulation makes Chinese wildlife highly suitable for the assessment of legacy, novel and emerging environmental pollutants. In the present study, six species of amphibians, fish and birds were sampled from paddy fields in the Yangtze River Delta (YRD) were screened for OHCs. Some extensive contamination was found, both regarding number and concentrations of the analytes, among the species assessed. High concentrations of chlorinated paraffins were found in the snake, Short-tailed mamushi (range of 200-340 mu g g(-1) lw), Peregrine falcon (8-59 mu g g(-1) lw) and Asiatic toad (97 mu g g(-1) lw). Novel contaminants and patterns were observed; octaCBs to decaCB made up 20% of the total polychlorinated biphenyls (PCBs) content in the samples and new OHCs, substituted with 5-8 chlorines, were found but are not yet structurally confirmed. In addition, Dechlorane 602 (DDC-DBF) and numerous other OHCs (DDTs, hexachlorocyclohexanes (HCHs), polybrominated diphenyl ethers (PBDEs), hexbromocyclododecane (HBCDD), chlordane, heptachlor, endosulfan and Mirex) were found in all species analyzed. These data show extensive chemical contamination of wildlife in the YRD with a suite of OHCs with both known and unknown toxicities, calling for further indepth studies.

  • 704.
    Zhou, Yihui
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China.
    Chen, Qiaofeng
    Du, Xinyu
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Qiu, Yanling
    Ye, Lu
    Zhu, Zhiliang
    Zhao, Jianfu
    Occurrence and trophic magnification of polybrominated diphenyl ethers (PBDEs) and their methoxylated derivatives in freshwater fish from Dianshan Lake, Shanghai, China2016In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 219, p. 932-938Article in journal (Refereed)
    Abstract [en]

    In this study, polybrominated diphenyl ethers (PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) were analyzed in eleven freshwater fish species from Dianshan Lake, Shanghai, China. The highest concentrations of PBDEs and MeO-PBDEs were found in snakehead, with mean values of 38 ng g(-1) lw and 4.2 ng g(-1) lw, respectively. BDE-47 was the predominant congener of PBDEs, followed by BDE-154. Congener pattern variation of PBDEs was observed among different fish species, implying differences in biotransformation potential among fish. Yellow catfish showed highest concentrations of BDE-99, -153 and -183, suggesting that it is more resistant to debromination than any other fish analyzed in the present study. Trophic magnification factors were in the range of 1.35-1.81 for all the PBDE congeners, but not for 2'-MeO-BDE-68. Negative relationship was observed between PBDEs concentration and sample size (length and weight), indicating fish size dilution effect.

  • 705.
    Zhou, Yihui
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China.
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Qiu, Yanling
    Bignert, Anders
    Zhu, Zhiliang
    Zhao, Jianfu
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish Toxicology Sciences Research Center, Sweden; Tongji University, China.
    A novel pollution pattern: Highly chlorinated biphenyls retained in Black-crowned night heron (Nycticorax nycticorax) and Whiskered tern (Chlidonias hybrida) from the Yangtze River Delta2016In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 150, p. 491-498Article in journal (Refereed)
    Abstract [en]

    Contamination of organochlorine pesticides (OCPs), polychlorinated diphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and their methylated counterparts (MeO-PBDEs) were determined in Black-crowned night heron (Nycticorax nycticorax) and Whiskered tern (Chlidonias hybrida) from two drinking water sources, e.g. Tianmu lake and East Tai lake in Yangtze River Delta, China. A novel PCBs contamination pattern was detected, including 11% and 6.9% highly chlorinated biphenyls (PCBs with eight to ten chlorines) in relation to total PCB concentrations in the Black-crowned night heron and Whiskered tern eggs, respectively. The predominating OCPs detected in the present study were 4,4'-DDE, with concentration range 280-650 ng g(-1) lw in Black crowned night heron and 240-480 ng g(-1) lw in Whiskered tern, followed by beta-HCH and Mirex. 6MeO-BDE-90 and 6-MeO-BDE-99 are the two predominant congeners of MeO-PBDEs whereas 6-OH-BDE-47 contributes mostly to the OH-PBDEs in both species. Contamination level was considered as median or low level compared global data.

  • 706.
    Zhou, Yihui
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Stewart, Kathryn
    Rantakokko, Panu
    Bignert, Anders
    Ruokojärvi, Päivi
    Kiviranta, Hannu
    Qiu, Yanling
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ma, Zhijun
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    High concentrations of OCDD and related chemicals in heron and tern eggs from Yangtze River Delta indicating PCP originArticle in journal (Other academic)
  • 707.
    Zhou, Yihui
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China.
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Stewart, Kathryn
    Rantakokko, Panu
    Bignert, Anders
    Ruokojärvi, Päivi
    Kiviranta, Hannu
    Qiu, Yanling
    Ma, Zhijun
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Tongji University, China; Karolinska Institute, Sweden.
    Human exposure to PCDDs and their precursors from heron and tern eggs in the Yangtze River Delta indicate PCP origin2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 225, p. 184-192Article in journal (Refereed)
    Abstract [en]

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are highly toxic to humans and wildlife. In the present study, PCDD/Fs were analyzed in the eggs of whiskered terns (Chlidonias hybrida), and genetically identified eggs from black-crowned night herons (Nycticorax nycticorax) sampled from two lakes in the Yangtze River Delta area, China. The median toxic equivalent (TEQ) of PCDD/Fs were 280 (range: 95-1500) and 400 (range: 220-1100) pg TEQ g(-1) lw (WHO, 1998 for birds) in the eggs of black-crowned night heron and whiskered tern, respectively. Compared to known sources, concentrations of PCDDs relative to the sum of PCDD/Fs in bird eggs, demonstrated high abundance of octachlorodibenzo-p-dioxin (OCDD), 1,2,3,4,6,7,8-heptaCDD and 1,2,3,6,7,8-hexaCDD indicating pentachlorophenol (PCP), and/or sodium pentachlorophenolate (Na-PCP) as significant sources of the PCDD/Fs. The presence of polychlorinated diphenyl ethers (PCDEs), hydroxylated and methoxylated polychlorinated diphenyl ethers (OH-and Me0-PCDEs, known impurities in PCP products), corroborates this hypothesis. Further, significant correlations were found between the predominant congener CDE-206, 3'-OH-CDE-207, 2'-MeO-CDE-206 and OCDD, indicating a common origin. Eggs from the two lakes are sometimes used for human consumption. The WHO health-based tolerable intake of PCDD/Fs is exceeded if eggs from the two lakes are consumed regularly on a weekly basis, particularly for children. The TEQs extensively exceed maximum levels for PCDD/Fs in hen eggs and egg products according to EU legislation (2.5 pg TEQ g(-1)/w). The results suggest immediate action should be taken to manage the contamination, and further studies evaluating the impacts of egg consumption from wild birds in China. Likewise, studies on dioxins and other POPs in common eggs need to be initiated around China.

  • 708. Zhou, Yihui
    et al.
    Yin, Ge
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Du, Xinyu
    Xu, Maoying
    Qiu, Yanling
    Ahlqvist, Patrik
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Chen, Qiaofeng
    Zhao, Jianfu
    Short-chain chlorinated paraffins (SCCPs) in a freshwater food web from Dianshan Lake: Occurrence level, congener pattern and trophic transfer2018In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 615, p. 1010-1018Article in journal (Refereed)
    Abstract [en]

    Short-chain chlorinated paraffins (SCCPs) are new group of persistent organic pollutants (POPs) listed in the Stockholm Convention. The Yangtze River Delta is among the industrially most developed areas in China, supporting a large production and consumption of chlorinated paraffins (CPs). Despite this, there is very limited data on the environmental exposure of SCCPs from the region. This study analyzed SCCPs in 14 wild aquatic organisms from Dianshan Lake, Shanghai, China. The concentrations of total SCCPs ranged from 10 to 1300 mu g g(-1) lipid weight, with significantly higher levels (p < 0.05) in benthic (benthic fish and invertebrates) than in non-benthic species (pelagic and mesopelagic fish). The abundance of C-10 congeners was much higher in the benthic species compared to in the non-benthic species. The calculated trophic magnification factors (TMFs) of SCCP congeners varied from 1.19 (C10H12Cl10) to 1.57 (C13H20Cl8). The TMFs were significantly correlated (p < 0.01) with carbon-chain length in a positive linear relationship and with Log K-ow in a parabolic curve relationship. Considering the high concentrations of SCCPs in wild aquatic organisms and the trophic magnification observed in the freshwater food web, further studies should be undertaken to assess the environmental fate of SCCPs and the public health risk in the Yangtze River Delta.

  • 709.
    Ziarrusta, Haizea
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of the Basque Country (UPV/EHU), Spain.
    Mijangos, Leire
    Izagirre, Urtzi
    Plassmann, Merle M.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Benskin, Jonathan P.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Anakabe, Eneritz
    Olivares, Maitane
    Zuloaga, Olatz
    Bioconcentration and Biotransformation of Amitriptyline in Gilt-Head Bream2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 4, p. 2464-2471Article in journal (Refereed)
    Abstract [en]

    Extensive global use of the serotonin norepinephrine reuptake inhibitor Amitriptyline (AMI) for treatment of mental health problems has led to its common occurrence in the aquatic environment. To assess AMI bioconcentration factors, tissue distribution, and metabolite formation in fish, we exposed gilt-head bream (Sparus aurata) to AMI in seawater for 7 days at two concentrations (0.2 mu g/L and 10 mu g/L). Day 7 proportional bioconcentration factors (BCFs) ranged from 6 (10 mu g/L dose, muscle) to 127 (0.2 mu g/L dose, brain) and were consistently larger at the low dose level. The relative tissue distribution of AMI was consistent at both doses, with concentrations decreasing in the order brain approximate to gill > liver > plasma > bile >> muscle. Using a suspect screening workflow based on liquid chromatography-high resolution (Orbitrap) mass spectrometry we identified 33 AMI metabolites (both Phase I and Phase II), occurring mostly in bile, liver and plasma. Ten structures are reported for the first time. Remarkably, all 33 metabolites retained the tricyclic ring structure common to tricyclic antidepressants, which may be toxicologically relevant. Collectively these data indicate that, in addition to AMI, a broad suite of metabolites should be included in biomonitoring campaigns in order to fully characterize exposure in aquatic wildlife.

  • 710.
    Zieger, Paul
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Aalto, P. P.
    Aaltonen, V.
    Aijala, M.
    Backman, J.
    Hong, J.
    Komppula, M.
    Krejci, Radovan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Helsinki, Finland.
    Laborde, M.
    Lampilahti, J.
    de Leeuw, G.
    Pfuller, A.
    Rosati, B.
    Tesche, Matthias
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tunved, Peter
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vaananen, R.
    Petaja, T.
    Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 13, p. 7247-7267Article in journal (Refereed)
    Abstract [en]

    Ambient aerosol particles can take up water and thus change their optical properties depending on the hygroscopicity and the relative humidity (RH) of the surrounding air. Knowledge of the hygroscopicity effect is of crucial importance for radiative forcing calculations and is also needed for the comparison or validation of remote sensing or model results with in situ measurements. Specifically, particle light scattering depends on RH and can be described by the scattering enhancement factor f(RH), which is defined as the particle light scattering coefficient at defined RH divided by its dry value (RH < 30-40 %). Here, we present results of an intensive field campaign carried out in summer 2013 at the SMEAR II station at Hyytiala, Finland. Ground-based and airborne measurements of aerosol optical, chemical and microphysical properties were conducted. The f(RH) measured at ground level by a humidified nephelometer is found to be generally lower (e.g. 1.63 +/- 0.22 at RH = 85% and lambda = 525 nm) than observed at other European sites. One reason is the high organic mass fraction of the aerosol encountered at Hyytiala to which f(RH) is clearly anti-correlated (R-2 approximate to 0.8). A simplified parametrization of f(RH) based on the measured chemical mass fraction can therefore be derived for this aerosol type. A trajectory analysis revealed that elevated values of f(RH) and the corresponding elevated inorganic mass fraction are partially caused by transported hygroscopic sea spray particles. An optical closure study shows the consistency of the ground-based in situ measurements. Our measurements allow to determine the ambient particle light extinction coefficient using the measured f(RH). By combining the ground-based measurements with intensive aircraft measurements of the particle number size distribution and ambient RH, columnar values of the particle extinction coefficient are determined and compared to columnar measurements of a co-located AERONET sun photometer. The water uptake is found to be of minor importance for the column-averaged properties due to the low particle hygroscopicity and the low RH during the daytime of the summer months. The in situ derived aerosol optical depths (AOD) clearly correlate with directly measured values of the sun photometer but are substantially lower compared to the directly measured values (factor of similar to 2-3). The comparison degrades for longer wavelengths. The disagreement between in situ derived and directly measured AOD is hypothesized to originate from losses of coarse and fine mode particles through dry deposition within the canopy and losses in the in situ sampling lines. In addition, elevated aerosol layers (above 3 km) from long-range transport were observed using an aerosol lidar at Kuopio, Finland, about 200 km east-northeast of Hyytiala. These elevated layers further explain parts of the disagreement.

  • 711.
    Zieger, Paul
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vaisanen, O.
    Corbin, J. C.
    Partridge, Dan G.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bastelberger, S.
    Mousavi-Fard, M.
    Rosati, B.
    Gysel, M.
    Krieger, U. K.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Nenes, A.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Virtanen, A.
    Salter, Matthew E.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Revising the hygroscopicity of inorganic sea salt particles2017In: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, article id 15883Article in journal (Refereed)
    Abstract [en]

    Sea spray is one of the largest natural aerosol sources and plays an important role in the Earth's radiative budget. These particles are inherently hygroscopic, that is, they take-up moisture from the air, which affects the extent to which they interact with solar radiation. We demonstrate that the hygroscopic growth of inorganic sea salt is 8-15% lower than pure sodium chloride, most likely due to the presence of hydrates. We observe an increase in hygroscopic growth with decreasing particle size (for particle diameters <150 nm) that is independent of the particle generation method. We vary the hygroscopic growth of the inorganic sea salt within a general circulation model and show that a reduced hygroscopicity leads to a reduction in aerosol-radiation interactions, manifested by a latitudinal-dependent reduction of the aerosol optical depth by up to 15%, while cloud-related parameters are unaffected. We propose that a value of kappa(s) = 1.1 (at RH = 90%) is used to represent the hygroscopicity of inorganic sea salt particles in numerical models.

  • 712.
    Zou, Hongyan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    The measurement of chemical persistence in the field by benchmarking: Theory and Experiment2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Persistence is one of the core criteria in chemical exposure and hazard assessment. It is often defined as the half-life for the removal of a chemical from a specified environment by transformation. Chemicals with long transformation half-lives may pose high risks for wildlife or humans and be subject to long-range transport to remote areas. It is challenging to measure persistence directly in the field in view of the complexity of the natural environment and spatial and temporal variability in environmental conditions that may affect degradation.

    The mass balance approach is the most commonly used method for field measurement of persistence. In this thesis an alternative to the traditional mass balance approach that uses benchmarking is proposed and evaluated using models and field application. The benchmarking approach compares the relative behavior of chemicals, rather than measuring the absolute value of a property. The unknown property (persistence in this thesis) of test chemicals can be estimated by comparison against another chemical for which this property is known.

    In Paper I, the potential of benchmarking to measure persistence in the field was evaluated by modeling. A framework for applying benchmarking to measure persistence in the field was developed. Lake systems with hydraulic residence times of the order of months were identified as appropriate field sites to measure the persistence of chemicals that are close to the regulatory thresholds, which are also on the scale of months. Field studies in two Swedish lakes were conducted. Both are shallow lakes, whereas Norra Bergundasjön (Paper II) has a longer residence time (four months) than Boren (one to two months; Paper III). In Paper II the benchmarking approach was tested to measure the persistence of a group of chemicals that were expected to stay in the water phase. Acesulfame K (artificial sweetener) without observable degradation in the lake was used as the benchmark chemical. The persistence of 9 pharmaceuticals and one X-ray contrast agent was measured to range from <1-2 days (ketoprofen) to 580-5700 days (carbamazepine). The results obtained using the benchmarking approach agreed well with the mass balance approach, indicating that the benchmarking approach can be a valid and useful method to measure persistence in the field. In Paper III the seasonality in chemical persistence was investigated by benchmarking. The seasonal difference in chemical persistence was found to be largest between spring and autumn. The persistence of 5 chemicals in spring were lower than in autumn, mainly attributed to lower temperature and less sunlight in autumn. The spatial variation of the persistence of chemicals was observed by comparing the persistence of chemicals in spring in the two lakes. Thus benchmarking is a useful tool to study the temporal and spatial variation of persistence in the real environment.  

    Paper IV explores the potential of benchmarking thoroughly and the application of benchmarking in a regulatory context. Benchmarking could facilitate more field measurements of persistence, leading to a better understanding of the temporal and spatial variability of persistence in various environments and a basis for lab-to-field extrapolation. Besides quantitative estimation of persistence in the field, benchmarking can be applied to determine the relative magnitude of persistence, called threshold benchmarking which could be a valuable tool in regulatory processes.

  • 713.
    Zou, Hongyan
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kierkegaard, Amelie
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    MacLeod, Matthew
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    McLachlan, Michael S.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Using Chemical Benchmarking to Determine the Persistence of Chemicals in a Swedish Lake2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 3, p. 1646-1653Article in journal (Refereed)
    Abstract [en]

    It is challenging to measure the persistence of chemicals under field conditions. In this work, two approaches for measuring persistence in the field were compared: the chemical mass balance approach, and a novel chemical benchmarking approach. Ten pharmaceuticals, an X-ray contrast agent, and an artificial sweetener were studied in a Swedish lake. Acesulfame K was selected as a benchmark to quantify persistence using the chemical benchmarking approach. The 95% confidence intervals of the half-life for transformation in the lake system ranged from 780-5700 days for carbamazepine to <1-2 days for ketoprofen. The persistence estimates obtained using the benchmarking approach agreed well with those from the mass balance approach (1-21% difference), indicating that chemical benchmarking can be a valid and useful method to measure the persistence of chemicals under field conditions. Compared to the mass balance approach, the benchmarking approach partially or completely eliminates the need to quantify mass flow of chemicals, so it is particularly advantageous when the quantification of mass flow of chemicals is difficult. Furthermore, the benchmarking approach allows for ready comparison and ranking of the persistence of different chemicals.

  • 714.
    Zou, Hongyan
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Radke, Michael
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kierkegaard, Amelie
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    McLachlan, Michael S.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Temporal Variation of Chemical Persistence in a Swedish Lake Assessed by Benchmarking2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 16, p. 9881-9888Article in journal (Refereed)
    Abstract [en]

    Chemical benchmarldng was used to investigate the temporal variation of the persistence of chemical contaminants in a Swedish lake. The chemicals studied included 12 pharmaceuticals, an artificial sweetener, and an X-ray contrast agent. Measurements were conducted in late spring, late autumn, and winter. The transformation half-life in the lake could be quantified for 7 of the chemicals. It ranged from several days to hundreds of days. For 5 of the chemicals (bezafibrate, climbazole, diclofenac, furosemide, and hydrochlorothiazide), the measured persistence was lower in late spring than in late autumn. This may have been caused by lower temperatures and/or less irradiation during late autumn. The seasonality in chemical persistence contributed to changes in chemical concentrations in the lake during the year. The impact of seasonality of persistence was compared with the impact of other important variables determining concentrations in the lake: chemical inputs and water flow/dilution. The strongest seasonal variability in chemical concentration in lake water was observed for hydrochlorothiazide (over a factor of 10), and this was attributable to the seasonality in its persistence.

  • 715.
    Zurita, Javier
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Amino acids with relevance to health, climate and the environment: Development of mass spectrometric methods2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Amino acids play vital roles in health, either in their native form or chemically modified. Some studies have linked certain non-proteinogenic amino acids to neurodegenerative diseases, such as in the case of β-methylaminoalanine (BMAA). Various environmental pollutants, including carcinogenic polycyclic aromatic compounds, are able to react forming adducts with blood proteins. Amino acids may also be essential in chemical ecology as constituents of flower nectar, potentially used by common feeders as butterflies to synthesize pheromones. Additionally, proteinaceous materials have been detected in aerosols with an apparent potential to influence climate, possibly having a role in cloud formation.

    The determination of amino acids presents many challenges, due to the fact that they are most often constituents of complex sample matrices that contain a high level of chemical interferences. In this respect, mass spectrometry (MS) is a selective and sensitive analytical tool that can be used to measure amino acids in biological samples.

    In this work, several analytical methods based on MS were developed. (i) First, derivatization with a permanently charged N-hydroxysuccinimide ester of N-butylnicotinic acid (C4-NA-NHS) was used to increase the sensitivity and selectivity for amino acids. This strategy was applied to localize BMAA in both visceral and non-visceral parts of blue mussels. (ii) Moreover, a method was developed to separate and determine L- and D- BMAA in cycad seeds by derivatization with a chiral reagent, (+)-1-(9-fluorenyl) ethyl chloroformate (FLEC). Together with L-BMAA, appreciable amounts of D-BMAA (50.13 ± 0.05 and 4.08 ± 0.04 µg BMAA/g Cycas micronesica, wet weight, respectively) were detected for the first time after enzymatic digestion, suggesting D-BMAA may be bound to proteins or may be a conjugate and released only after hydrolysis. (iii) Derivatization with C4-NA-NHS was applied as well for the determination of amino acids in nectar of Bunias orientalis. The presence of tryptophan and phenylalanine, purportedly used to synthesize anti-aphrodisiac pheromones by nectar feeders (adult male butterflies), could then be observed. (iv) Furthermore, the profiling of amino acids in Arctic aerosols was carried out and was used to measure the contribution of free and polyamino acids in aerosol formation. Levels detected were in the range of 0.02-2914 pmol/m3 sampled air. For the first time the measurement of polyamino acids in the Arctic atmosphere was reported. Additionally, possible anthropogenic and marine sources were suggested. The results support the hypothesis that proteinaceous materials act as cloud condensation nuclei over the Arctic. (v) Finally, a method was developed employing selective chromatography/high-resolution MS to identify histidine and lysine adducts in serum albumin of mice exposed to the carcinogen benzo(a)pyrene, as well as in human samples in vivo. Adduct isomers from diol epoxide metabolites could be detected in serum albumin from human samples at attomole/mg levels. This work shows the possibility of future exposure measurements from these compounds in different groups of the population.

    This thesis presents the development of improved analytical methodologies for detecting and identifying trace levels of amino acids, to investigate their relevance in health, climate and the environment.

  • 716.
    Zurita, Javier
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Motwani, Hitesh V.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Souliotos, Vassilis L
    Kyrtopoulos, Soterios A
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Detection of benzo[a]pyrene diol epoxide adducts to histidine and lysine in serum albumin in vivo by high-resolution-tandem mass spectrometryManuscript (preprint) (Other academic)
  • 717.
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In Response: Reporting recommendations to ensure reliability and reproducibility of ecotoxicity studies—A tripartite initiative2016In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 35, no 5, p. 1072-1073Article in journal (Other academic)
  • 718.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Berg, Cecilia
    Björlenius, Berndt
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Brunström, Björn
    Fick, Jerker
    Gunnarsson, Lina
    Larsson, D. G. Joakim
    Sumpter, John P.
    Tysklind, Mats
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Improving Environmental Risk Assessment of Human Pharmaceuticals2015In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, no 9, p. 5336-5345Article in journal (Refereed)
    Abstract [en]

    This paper presents 10 recommendations for improving the European Medicines Agency's guidance for environmental risk assessment of human pharmaceutical products. The recommendations are based on up-to-date, available science in combination with experiences from other chemical frameworks such as the REACH-legislation for industrial chemicals. The recommendations concern: expanding the scope of the current guideline; requirements to assess the risk for development of antibiotic resistance; jointly performed assessments; refinement of the test proposal; mixture toxicity assessments on active pharmaceutical ingredients with similar modes of action; use of all available ecotoxicity studies; mandatory reviews; increased transparency; inclusion of emission data from production; and a risk management option. We believe that implementation of our recommendations would strengthen the protection of the environment and be beneficial to society. Legislation and guidance documents need to be updated at regular intervals in order to incorporate new knowledge from the scientific community. This is particularly important for regulatory documents concerning pharmaceuticals in the environment since this is a research field that has been growing substantially in the last decades.

  • 719.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Beronius, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Weight of evidence evaluation and systematic review in EU chemical risk assessment: Foundation is laid but guidance is needed2016In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 92-93, p. 590-596Article, review/survey (Refereed)
    Abstract [en]

    The aim of this review was to investigate if and how the application of weight of evidence (WoE) evaluation or systematic review (SR) in chemical risk assessment is promoted within different regulatory frameworks in the European Union. Legislative and relevant guidance documents within nine regulatory frameworks were scrutinized and compared. WoE evaluation or SR is promoted in seven of the investigated frameworks but sufficient guidance for how to perform these processes is generally lacking. None of the investigated frameworks give enough guidance for generating robust and reproducible WoE evaluations or SRs. In conclusion, the foundation for use of WoE evaluation and SR is laid-in the majority of the investigated frameworks, but there is a need to provide more structured and detailed guidance. In order to make the process of developing guidance as efficient as possible, and to ensure smooth transfer of risk assessment's between frameworks if a chemical is risk assessed both as, for example, a biocide and an industrial chemical, it is recommended that guidance is developed jointly by the European regulatory agencies.

  • 720.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Brenig, Mattheus
    Führ, Martin
    Schenten, Julian
    Refining tools to bridge the gap between academia and chemical regulation: perspectives for WikiREACH2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 12, p. 1466-1473Article, review/survey (Refereed)
    Abstract [en]

    Regulatory hazard and risk assessments of chemical substances have to include all reliable and relevant data to be credible and complete. However, screening the literature for appropriate studies and extracting data is burdensome. Therefore, reducing impediments by making data easily and readily accessible to risk assessors could result in more comprehensive hazard and risk assessments. In this paper, we study WikiPharma, a database that aggregates ecotoxicity data for pharmaceuticals, extracted from peerreviewed studies. The use of the WikiPharma database is explored to develop strategies on how similar tools can bridge between science and policy by providing risk assessors with easily accessible summary data. Specifically, adapting the concept of WikiPharma to industrial chemicals regulated under the REACH regulation is discussed. Experiences with WikiPharma show that there is interest in using peerreviewed studies in regulatory decision-making. However, tools like WikiPharma require constant updates. Hence, as for WikiREACH, effective incentives are needed to motivate researchers to feed in relevant data for regulatory assessments. Besides, support by automated processes can aid in the labourintensive activity of gathering data. To ensure that such a tool is continuously maintained and compatible with the regulatory system, and thereby useful for hazard and risk assessments of chemicals, it would benefit from being developed in collaboration with the major stakeholders in the field, i.e. regulatory agencies, academia, industry, scientific journals, and providers of research network platforms.

  • 721.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Christiansen, Sofie
    Hanberg, Annika
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Andersson, Lars
    Andersen, Sjur
    Appelgren, Henrik
    Bjørge, Christine
    Clausen, Ian Henning
    Eide, Dag Markus
    Hartmann, Nanna B.
    Husøy, Trine
    Halldórsson, Halldór Pálmar
    van der Hagen, Marianne
    Ingre-Khans, Ellen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lillicrap, Adam David
    Beltoft, Vibe Meister
    Mörk, Anna-Karin
    Murtomaa-Hautala, Mari
    Nielsen, Elsa
    Ólafsdóttir, Kristín
    Palomäki, Jaana
    Papponen, Hinni
    Reiler, Emilie Marie
    Stockmann-Juvala, Helene
    Suutari, Tiina
    Tyle, Henrik
    Beronius, Anna
    A call for action: Improve reporting of research studies to increase the scientific basis for regulatory decision-making2018In: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 38, no 5, p. 783-785Article in journal (Refereed)
    Abstract [en]

    This is a call for action to scientific journals to introduce reporting requirements for toxicity and ecotoxicity studies. Such reporting requirements will support the use of peer-reviewed research studies in regulatory decision-making. Moreover, this could improve the reliability and reproducibility of published studies in general and make better use of the resources spent in research.

  • 722.
    Ågerstrand, Marlene
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sobek, Anna
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lilja, Karl
    Linderoth, Maria
    Wendt-Rasch, Lina
    Wernersson, Ann-Sofie
    Rudén, Christina
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    An academic researcher's guide to increased impact on regulatory assessment of chemicals2017In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, no 5, p. 644-655Article in journal (Refereed)
    Abstract [en]

    The interactions between academic research and regulatory assessment of chemicals may in theory seem straightforward: researchers perform studies, and these studies are used by regulators for decision-making. However, in practice the situation is more complex, and many factors decide a research study's regulatory use. According to several EU chemical legislations, all available and relevant studies can be used in hazard and risk assessment of chemicals. However, in practice, standard tests conducted under GLP and sponsored and provided by industry are predominantly used. Peer-reviewed studies from independent sources are often disregarded or disputed since they often do not comply with regulatory data requirements and quality criteria. To help bridge such a gap, the aim of this paper is to give an overview of the general workings of legislation of chemicals and propose a set of actions to increase the usability of research data. In the end, this may increase the use of academic research for decision-making and ultimately result in more science-based policies. From a policy perspective, useful scientific evidence comprises those studies that are sufficiently reliable and relevant. This is not in contradiction to the aims of research and generally accepted scientific standards.

  • 723. Åkerblom, Staffan
    et al.
    Meili, Markus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bishop, Kevin
    Organic Matter in Rain: An Overlooked Influence on Mercury Deposition2015In: Environmental Science and Technology Letters, E-ISSN 2328-8930, Vol. 2, no 4, p. 128-132Article in journal (Refereed)
    Abstract [en]

    The importance of Hg emissions for deposition will be scrutinized in the future as new legislation to control emissions of Hg to the atmosphere comes into effect. We show that mercury (Hg) concentrations in rainfall are closely linked to organic matter (OM) with consistent Hg/TOC ratios over large spatial scales decreasing from that in an open field (OF, 1.5 mu g g(-1)) to that in throughfall (TF, 0.9 mu g g(-1)). The leaf area index was positively correlated with both TF [Hg] and total organic carbon ([TOC]), but not the Hg/TOC ratio. This study shows that the progression in the Hg/TOC ratio through catchments starts in precipitation with Hg/TOCbulk dep > Hg/TOCsoil (water) > Hg/TOCstreamwater These findings raise an intriguing question about the extent to which it is not just atmospheric [Hg] but also OM that influences [Hg] in precipitation. This question should be resolved to improve the ability to discern the importance of changing global Hg emissions for deposition of Hg at specific sites.

  • 724.
    Österlund, Nicklas
    et al.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kulkarni, Yashraj S.
    Misiaszek, Agata D.
    Wallin, Cecilia
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Krüger, Dennis M.
    Liao, Qinghua
    Mashayekhy Rad, Farshid
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jarvet, Jüri
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Strodel, Birgit
    Wärmländer, Sebastian K. T. S.
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kamerlin, Shina C. L.
    Gräslund, Astrid
    Stockholm University, Faculty of Science, Department of Biochemistry and Biophysics.
    Amyloid-beta Peptide Interactions with Amphiphilic Surfactants: Electrostatic and Hydrophobic Effects2018In: ACS Chemical Neuroscience, ISSN 1948-7193, E-ISSN 1948-7193, Vol. 9, no 7, p. 1680-1692Article in journal (Refereed)
    Abstract [en]

    The amphiphilic nature of the amyloid-beta (A beta) peptide associated with Alzheimer's disease facilitates various interactions with biomolecules such as lipids and proteins, with effects on both structure and toxicity of the peptide. Here, we investigate these peptide-amphiphile interactions by experimental and computational studies of A beta(1-40) in the presence of surfactants with varying physicochemical properties. Our findings indicate that electrostatic peptide-surfactant interactions are required for coclustering and structure induction in the peptide and that the strength of the interaction depends on the surfactant net charge. Both aggregation-prone peptide-rich coclusters and stable surfactant-rich coclusters can form. Only A beta(1-40) monomers, but not oligomers, are inserted into surfactant micelles in this surfactant-rich state. Surfactant headgroup charge is suggested to be important as electrostatic peptide-surfactant interactions on the micellar surface seems to be an initiating step toward insertion. Thus, no peptide insertion or change in peptide secondary structure is observed using a nonionic surfactant. The hydrophobic peptide-surfactant interactions instead stabilize the A beta monomer, possibly by preventing self-interaction between the peptide core and C terminus, thereby effectively inhibiting the peptide aggregation process. These findings give increased understanding regarding the molecular driving forces for A beta aggregation and the peptide interaction with amphiphilic biomolecules.

12131415 701 - 724 of 724
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf