Ändra sökning
Avgränsa sökresultatet
1234567 151 - 200 av 929
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf
Träffar per sida
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sortering
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
  • Standard (Relevans)
  • Författare A-Ö
  • Författare Ö-A
  • Titel A-Ö
  • Titel Ö-A
  • Publikationstyp A-Ö
  • Publikationstyp Ö-A
  • Äldst först
  • Nyast först
  • Skapad (Äldst först)
  • Skapad (Nyast först)
  • Senast uppdaterad (Äldst först)
  • Senast uppdaterad (Nyast först)
  • Disputationsdatum (tidigaste först)
  • Disputationsdatum (senaste först)
Markera
Maxantalet träffar du kan exportera från sökgränssnittet är 250. Vid större uttag använd dig av utsökningar.
  • 151. Cho, Chaeyoon
    et al.
    Kim, Sang-Woo
    Lee, Meehye
    Lim, Saehee
    Fang, Wenzheng
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Park, Rokjin J.
    Sheridan, Patrick J.
    Observation-based estimates of the mass absorption cross-section of black and brown carbon and their contribution to aerosol light absorption in East Asia2019Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 212, s. 65-74Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, we estimated the contribution of black carbon (BC) and brown carbon (BrC) to aerosol light absorption from surface in-situ and aerosol robotic network (AERONET) columnar observations. The mass absorption cross-section (MAC) of BC (MAC(BC)) was estimated to be 6.4 +/- 1.5 m(2) g(-1) at 565 mn from in-situ aerosol measurements at Gosan Climate Observatory (GCO), Korea, in January 2014, which was lower than those observed in polluted urban areas. A BrC MAC of 0.62 +/- 0.06 m(2) g(-1) (565 mn) in our estimate is approximately ten times lower than MACK at 565 nm. The contribution of BC and BrC to the carbonaceous aerosol absorption coefficient at 565 nm from the in-situ measurements was estimated at 88.1 +/- 7.4% and 11.9 +/- 7.4%, respectively at GCO. Similarly, the contribution of BC and BrC to the absorption aerosol optical depth (AAOD) for carbonaceous aerosol (CA), constrained by AERONET observations at 14 sites over East Asia by using different spectral dependences of the absorption (i.e., absorption Angstrom exponent) of BC and BrC, was 84.9 +/- 2.8% and 15.1 +/- 2.8% at 565 nm, respectively. The contribution of BC to CA AAOD was greater in urban sites than in the background areas, whereas the contribution of BrC to CA AAOD was higher in background sites. The overall contribution of BC to CA AAOD decreased by 73%-87% at 365 nm, and increased to 93%-97% at 860 nm. The contribution of BrC to CA AAOD decreased significantly with increasing wavelength from approximately 17% at 365 nm to 4% at 860 nm.

  • 152. Choi, J. H.
    et al.
    Jang, E.
    Yoon, Y. J.
    Park, J. Y.
    Kim, T.-W.
    Becagli, S.
    Caiazzo, L.
    Cappelletti, D.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Eleftheria, K.
    Park, K.-T.
    Jang, K. S.
    Influence of Biogenic Organics on the Chemical Composition of Arctic Aerosols2019Ingår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 33, nr 10, s. 1238-1250Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We use an ultrahigh-resolution 15-T Fourier transform ion cyclotron resonance mass spectrometer to elucidate the compositional changes in Arctic organic aerosols collected at Ny-angstrom lesund, Svalbard, in May 2015. The Fourier transform ion cyclotron resonance mass spectrometer analysis of airborne organic matter provided information on the molecular compositions of aerosol particles collected during the Arctic spring period. The air mass transport history, combined with satellite-derived geographical information and chlorophyll concentration data, revealed that the molecular compositions of organic aerosols drastically differed depending on the origin of the potential source region. The protein and lignin compound populations contributed more than 70% of the total intensity of assigned molecules when the air masses mainly passed over the ocean region. Interestingly, the intensity of microbe-derived organics (protein and carbohydrate compounds) was positively correlated with the air mass exposure to phytoplankton biomass proxied as chlorophyll. Furthermore, the intensities of lignin and unsaturated hydrocarbon compounds, typically derived from terrestrial vegetation, increased with an increase in the advection time of the air mass over the ocean domain. These results suggest that the accumulation of dissolved biogenic organics in the Arctic Ocean possibly derived from both phytoplankton and terrestrial vegetation could significantly influence the chemical properties of Arctic organic aerosols during a productive spring period. The interpretation of molecular changes in organic aerosols using an ultrahigh-resolution mass spectrometer could provide deep insight for understanding organic aerosols in the atmosphere over the Arctic and the relationship of organic aerosols with biogeochemical processes in terms of aerosol formation and environmental changes.

  • 153. Christia, Christina
    et al.
    Poma, Giulia
    Harrad, Stuart
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sjöström, Ylva
    Leonards, Pim
    Lamoree, Marja
    Covaci, Adrian
    Occurrence of legacy and alternative plasticizers in indoor dust from various EU countries and implications for human exposure via dust ingestion and dermal absorption2019Ingår i: Environmental Research, ISSN 0013-9351, E-ISSN 1096-0953, Vol. 171, s. 204-212Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Plasticizers are a category of chemicals extensively used in consumer products and, consequently, their presence is ubiquitous in the indoor environment. In the present study, an analytical method has been developed for the quantification of plasticizers (7 legacy phthalate esters (LPEs) and 14 alternative plasticizers (APs)) in indoor floor dust based on ultrasonic and vortex extraction, Florisil fractionation and GC-(EI)-MS analysis. Dust samples (n = 54) were collected from homes, offices, and daycare centers from different EU countries (Belgium, the Netherlands, Ireland and Sweden). Method LOQs ranged from 0.2 to 5 mu g/g. Tri-n-hexyl trimellitate (THTM) was not detected in any sample, whereas dimethyl phthalate (DMP), diphenyl phthalate and acetyl triethyl citrate (ATEC) were detected only in 6, 2 and 1 out of 54 samples, respectively. The highest concentrations of plasticizers were measured in Swedish offices, at a mean concentration of total plasticizers of 1800 mu g/g, followed by Swedish daycare centers at 1200 and 670 mu g/g for winter and spring sampling, respectively. Generally, the contribution of APs was slightly higher than for LPEs for all indoor environments (mean contribution 60% and 40%, respectively based on contributions per indoor environment). For the APs, main contributors were DINP in Belgian homes (28%), Swedish offices (60%), Swedish daycare centers (48%), and Dutch offices (31%) and DEHT in Belgian (28%), Irish (40%) and Dutch homes (37%) of total APs. The predominant LPE was bis-2-ethylhexyl-phthalate (DEHP) with a mean contribution varying from 60% to 85% of total LPEs. Human exposure was evaluated for dust ingestion and dermal absorption using hazard quotients (HQs) of plasticizers (ratio between average daily doses and the reference dose). None of the HQs of plasticizers exceeded 1, meaning that the risk for adverse human health effects from these plasticizers via dust ingestion and dermal absorption is unlikely.

  • 154. Christiansen, Sigurd
    et al.
    Salter, Matthew E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Nguyen, Quynh T.
    Bilde, Merete
    Sea Spray Aerosol Formation: Laboratory Results on the Role of Air Entrainment, Water Temperature, and Phytoplankton Biomass2019Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, nr 22, s. 13107-13116Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Sea spray aerosol (SSA) emission is a complex process affected by various controlling factors. This work seeks to deconvolute some of this complexity in a controlled laboratory setting using a plunging jet by varying three key parameters, one at a time: (1) air entrainment rate, (2) seawater temperature, and (3) biomass of phytoplankton. The production of SSA is found to vary linearly with air entrainment rate. By normalizing the production flux to air entrainment rate, we observe nonlinear variation of the production efficiency of SSA with seawater temperature with a minimum around 6-10 degrees C. For comparison, SSA was also generated by detraining air into artificial seawater using a diffuser demonstrating that the production efficiency of SSA generated using a diffuser decreases almost linearly with increasing seawater temperature, and the production efficiency is, significantly higher than that for SSA generated using a plunging jet. Finally, by varying the amount of phytoplankton biomass we demonstrate that SSA particle production varies nonlinearly with the amount of biomass in seawater.

  • 155. Cirino, Glauber
    et al.
    Brito, Joel
    Barbosa, Henrique M. J.
    Rizzo, Luciana V.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    de Sá, Suzane S.
    Jimenez, Jose L.
    Palm, Brett B.
    Carbone, Samara
    Lavric, Jost V.
    Souza, Rodrigo A. F.
    Wolff, Stefan
    Walter, David
    Tota, Júlio
    Oliveira, Maria B. L.
    Martin, Scot T.
    Artaxo, Paulo
    Observations of Manaus urban plume evolution and interaction with biogenic emissions in GoAmazon 2014/52018Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 191, s. 513-524Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    As part of the Observations and Modeling of the Green Ocean Amazon (GoAmazon 2014/5) Experiment, detailed aerosol and trace gas measurements were conducted near Manaus, a metropolis located in the central Amazon Basin. Measurements of aerosol particles and trace gases were done downwind Manaus at the sites T2 (Tiwa Hotel) and T3 (Manacapuru), at a distance of 8 and 70 km from Manaus, respectively. Based on in-plume measurements closer to Manaus (site T2), the chemical signatures of city emissions were used to improve the interpretation of pollutant levels at the T3 site. We derived chemical and physical properties for the city's atmospheric emission ensemble, taking into account only air masses impacted by the Manaus plume at both sites, during the wet and dry season Intensive Operating Periods (IOPs). At T2, average concentrations of aerosol number (CN), CO and SO2 were 5500 cm(-3) (between 10 and 490 nm), 145 ppb and 0.60 ppb, respectively, with a typical ratio ACN/ACO of 60-130 particles cm(-3) ppb(-1). The aerosol scattering (at RH < 60%) and absorption at 637 nm at T2 ranged from 10 to 50 M m(-1) and 5-10 M m(-1), respectively, leading to a mean single scattering albedo (SSA) of 0.70. In addition to identifying periods dominated by Manaus emissions at both T2 and T3, the plume transport between the two sampling sites was studied using back trajectory calculations. Results show that the presence of the Manaus plume at site T3 was important mainly during the daytime and at the end of the afternoons. During time periods directly impacted by Manaus emissions, an average aerosol number concentration of 3200 cm(-3) was measured at T3. Analysis of plume evolution between T2 and T3 indicates a transport time of 4-5 h. Changes of submicron organic and sulfate aerosols ratios relative to CO (Delta OA/Delta CO and Delta SO4/Delta CO, respectively) indicate significant production of secondary organic aerosol (SOA), corresponding to a 40% mass increase in OA and a 30% in SO4 mass concentration. Similarly, during air mass arrival at T3 the SSA increased to 0.83 from 0.70 at T2, mainly associated with an increase in organic aerosol concentration. Aerosol particle size distributions show a strong decrease in the Aitken nuclei mode (10-100 nm) during the transport from T2 to T3, in particular above 30 nm, as a result of efficient coagulation processes into larger particles. A decrease of 30% in the particle number concentration and an increase of about 50 nm in geometric mean diameter were observed from T2 to T3 sites. The study of the evolution of aerosol properties downwind of the city of Manaus improves our understanding of how coupling of anthropogenic and biogenic sources may be impacting the sensitive Amazonian atmosphere.

  • 156. Clift, Roland
    et al.
    Sim, Sarah
    King, Henry
    Chenoweth, Jonathan L.
    Christie, Ian
    Clavreul, Julie
    Mueller, Carina
    Posthuma, Leo
    Boulay, Anne-Marie
    Chaplin-Kramer, Rebecca
    Chatterton, Julia
    DeClerck, Fabrice
    Druckman, Angela
    France, Chris
    Franco, Antonio
    Gerten, Dieter
    Goedkoop, Mark
    Hauschild, Michael Z.
    Huijbregts, Mark A. J.
    Koellner, Thomas
    Lambin, Eric F.
    Lee, Jacquetta
    Mair, Simon
    Marshall, Stuart
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mila i Canals, Llorenc
    Mitchell, Cynthia
    Price, Edward
    Rockström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Suckling, James
    Murphy, Richard
    The Challenges of Applying Planetary Boundaries as a Basis for Strategic Decision-Making in Companies with Global Supply Chains2017Ingår i: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 9, nr 2, artikel-id 279Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Planetary Boundaries (PB) framework represents a significant advance in specifying the ecological constraints on human development. However, to enable decision-makers in business and public policy to respect these constraints in strategic planning, the PB framework needs to be developed to generate practical tools. With this objective in mind, we analyse the recent literature and highlight three major scientific and technical challenges in operationalizing the PB approach in decision-making: first, identification of thresholds or boundaries with associated metrics for different geographical scales; second, the need to frame approaches to allocate fair shares in the 'safe operating space' bounded by the PBs across the value chain and; third, the need for international bodies to co-ordinate the implementation of the measures needed to respect the Planetary Boundaries. For the first two of these challenges, we consider how they might be addressed for four PBs: climate change, freshwater use, biosphere integrity and chemical pollution and other novel entities. Four key opportunities are identified: (1) development of a common system of metrics that can be applied consistently at and across different scales; (2) setting 'distance from boundary' measures that can be applied at different scales; (3) development of global, preferably open-source, databases and models; and (4) advancing understanding of the interactions between the different PBs. Addressing the scientific and technical challenges in operationalizing the planetary boundaries needs be complemented with progress in addressing the equity and ethical issues in allocating the safe operating space between companies and sectors.

  • 157.
    Coll, Claudia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Changes in sediment bacterial community composition throughout an OECD 308 test with ten micropollutantsManuskript (preprint) (Övrigt vetenskapligt)
  • 158.
    Coll, Claudia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindim, Claudia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sohn, Michael D.
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Prospects for finding Junge variability-lifetime relationships for micropollutants in the Danube river2019Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, nr 9, s. 1489-1497Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Persistence of chemical pollutants is difficult to measure in the field. Junge variability-lifetime relationships, correlating the relative standard deviation of measured concentrations with residence time, have been used to estimate persistence of air pollutants. Junge relationships for micropollutants in rivers could provide evidence that half-lives of compounds estimated from laboratory and field data are representative of half-lives in a specific system, location and time. Here, we explore the hypothesis that Junge relationships could exist for micropollutants in the Danube river using: (1) concentrations of six hypothetical chemicals modeled using the STREAM-EU fate and transport model, and (2) concentrations of nine micropollutants measured in the third Joint Danube Survey (JDS3) combined with biodegradation half-lives reported in the literature. Using STREAM-EU, we found that spatial and temporal variability in modeled concentrations was inversely correlated with half-life for the four micropollutants with half-lives <= 90 days. For these four modeled micropollutants, we found Junge relationships with slopes significantly different from zero in the temporal variability of concentrations at 88% of the 67 JDS3 measurement sites, and in the spatial variability of concentrations on 36% out of 365 modeled days. A Junge relationship significant at the 95% confidence level was not found in the spatial variability of nine micropollutants measured in the JDS3, nor in STREAM-EU-modeled concentrations extracted for the dates and locations of the JDS3. Nevertheless, our model scenarios suggest that Junge relationships might be found in future measurements of spatial and temporal variability of micropollutants, especially in temporal variability of pollutants measured downstream in the Danube river.

  • 159.
    Coll, Claudia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Raven, Bier
    Li, Zhe
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Langenheder, Silke
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Association between aquatic micropollutant degradation and river sediment bacterial communitiesManuskript (preprint) (Övrigt vetenskapligt)
  • 160. Conrad, Sarah
    et al.
    Ingri, Johan
    Gelting, Johan
    Nordblad, Fredrik
    Engström, Emma
    Rodushkin, Ilia
    Andersson, Per S.
    Porcelli, Don
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Semiletov, Igor
    Öhlander, Björn
    Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea2019Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 16, nr 6, s. 1305-1319Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Riverine Fe input is the primary Fe source for the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate (> 0.22 mu m), colloidal (0.22 mu m-1 kDa), and truly dissolved (< 1 kDa) fractions of Fe was carried out. The total Fe concentrations ranged from 0.2 to 57 mu M with Fe dominantly as particulate Fe. The loss of > 99% of particulate Fe and about 90% of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative delta Fe-56 values (relative to IRMM-14). The colloidal Fe phase showed negative delta Fe-56 values close to the river mouth (about -0.20 parts per thousand) and positive delta Fe-56 values in the outermost stations (about +0.10 parts per thousand). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative delta Fe-56 values, representing chemically reactive ferrihydrites. The positive delta Fe-56 values of the colloidal phase within the outer Lena River freshwater plume might represent Fe oxyhydroxides, which remain in the water column, and will be the predominant delta Fe-56 composition in the Arctic Ocean.

  • 161. Cooper, Glinda S.
    et al.
    Lunn, Ruth M.
    Ågerstrand, Marlene
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Glenn, Barbara S.
    Kraft, Andrew D.
    Luke, April M.
    Ratcliffe, Jennifer M.
    Study sensitivity: Evaluating the ability to detect effects in systematic reviews of chemical exposures2016Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 92-93, s. 605-610Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    A critical step in systematic reviews of potential health hazards is the structured evaluation of the strengths and weaknesses of the included studies; risk of bias is a term often used to represent this process, specifically with respect to the evaluation of systematic errors that can lead to inaccurate (biased) results (i.e. focusing on internal validity). Systematic review methods developed in the clinical medicine arena have been adapted for use in evaluating environmental health hazards; this expansion raises questions about the scope of risk of bias tools and the extent to which they capture the elements that can affect the interpretation of results from environmental and occupational epidemiology studies and in vivo animal toxicology studies, (the studies typically available for assessment of risk of chemicals). One such element, described here as sensitivity, is a measure of the ability of a study to detect a true effect or hazard. This concept is similar to the concept of the sensitivity of an assay; an insensitive study may fail to show a difference that truly exists, leading to a false conclusion of no effect Factors relating to study sensitivity should be evaluated in a systematic manner with the same rigor as the evaluation of other elements within a risk of bias framework. We discuss the importance of this component for the interpretation of individual studies, examine approaches proposed or in use to address it, and describe how it relates to other evaluation components. The evaluation domains contained within a risk of bias tool can include, or can be modified to include, some features relating to study sensitivity; the explicit inclusion of these sensitivity criteria with the same rigor and at the same stage of study evaluation as other bias-related criteria can improve the evaluation process. In some cases, these and other features may be better addressed through a separate sensitivity domain. The combined evaluation of risk of bias and sensitivity can be used to identify the most informative studies, to evaluate the confidence of the findings from individual studies and to identify those study elements that may help to explain heterogeneity across the body of literature.

  • 162.
    Cornelissen, Gerard
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Norwegian Geotechnical Institute, Norway; Norwegian University of Life Sciences (NMBU), Norway.
    Schaanning, Morten
    Gunnarsson, Jonas S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Eek, Espen
    A large-scale field trial of thin-layer capping of PCDD/F-contaminated sediments: Sediment-to-water fluxes up to 5 years post-amendment2016Ingår i: Integrated Environmental Assessment and Management, ISSN 1551-3777, E-ISSN 1551-3793, Vol. 12, nr 2, s. 216-221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The longer-term effect (3-5 y) of thin-layer capping on in situ sediment-to-surface water fluxes was monitored in a large-scale field experiment in the polychlorinated dibenzodioxin and dibenzofuran (PCDD/F) contaminated Grenlandfjords, Norway (4 trial plots of 10000 to 40000 m(2) at 30 to 100 m water depth). Active caps (designed thickness 2.5 cm) were established in 2 fjords, consisting of dredged clean clay amended with powdered activated carbon (PAC) from anthracite. These active caps were compared to 2 nonactive caps in one of the fjords (designed thickness 5 cm) consisting of either clay only (i.e., without PAC) or crushed limestone. Sediment-to-water PCDD/F fluxes were measured in situ using diffusion chambers. An earlier study showed that during the first 2 years after thin-layer capping, flux reductions relative to noncapped reference fields were more extensive at the fields capped with nonactive caps (70%-90%) than at the ones with PAC-containing caps (50%-60%). However, the present work shows that between 3 and 5 years after thin-layer capping, this trend was reversed and cap effectiveness in reducing fluxes was increasing to 80% to 90% for the PAC caps, whereas cap effectiveness of the nonactive caps decreased to 20% to 60%. The increasing effectiveness over time of PAC-containing active caps is explained by a combination of slow sediment-to-PAC mass transfer of PCDD/Fs and bioturbation by benthic organisms. The decreasing effectiveness of nonactive limestone and clay caps is explained by deposition of contaminated particles on top of the caps. The present field data indicate that the capping efficiency of thin active caps (i.e., enriched with PAC) can improve over time as a result of slow diffusive PCDD/F transfer from sediment to PAC particles and better mixing of the PAC by bioturbation. Integr Environ Assess Manag 2016;12:216-221.

  • 163.
    Cousins, Ian T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Balan, Simona A.
    Scheringer, Martin
    Weber, Roland
    Wang, Zhanyun
    Blum, Arlene
    Diamond, Miriam
    Fletcher, Tony
    Goldenman, Gretta
    Higgins, Christopher
    Lindeman, Avery E.
    Peaslee, Graham
    Trier, Xenia
    de Voogt, Pim
    Comment on Fluorotechnology Is Critical to Modern Life: The FluoroCouncil Counterpoint to the Madrid Statement2015Ingår i: Journal of Environmental Health Perspectives, ISSN 0091-6765, E-ISSN 1552-9924, Vol. 123, nr 7, s. A170-A170Artikel i tidskrift (Refereegranskat)
  • 164.
    Cousins, Ian T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Goldenman, Gretta
    Herzke, Dorte
    Lohmann, Rainer
    Miller, Mark
    Ng, Carla A.
    Patton, Sharyle
    Scheringer, Martin
    Trier, Xenia
    Vierke, Lena
    Wang, Zhanyun
    DeWitt, Jamie C.
    The concept of essential use for determining when uses of PFASs can be phased out2019Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, nr 11, s. 1803-1815Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Because of the extreme persistence of per- and polyfluoroalkyl substances (PFASs) and their associated risks, the Madrid Statement argues for stopping their use where they are deemed not essential or when safer alternatives exist. To determine when uses of PFASs have an essential function in modern society, and when they do not, is not an easy task. Here, we: (1) develop the concept of essential use based on an existing approach described in the Montreal Protocol, (2) apply the concept to various uses of PFASs to determine the feasibility of elimination or substitution of PFASs in each use category, and (3) outline the challenges for phasing out uses of PFASs in society. In brief, we developed three distinct categories to describe the different levels of essentiality of individual uses. A phase-out of many uses of PFASs can be implemented because they are not necessary for the betterment of society in terms of health and safety, or because functional alternatives are currently available that can be substituted into these products or applications. Some specific uses of PFASs would be considered essential because they provide for vital functions and are currently without established alternatives. However, this essentiality should not be considered as permanent; rather, constant efforts are needed to search for alternatives. We provide a description of several ongoing uses of PFASs and discuss whether these uses are essential or non-essential according to the three essentiality categories. It is not possible to describe each use case of PFASs in detail in this single article. For follow-up work, we suggest further refining the assessment of the use cases of PFASs covered here, where necessary, and expanding the application of this concept to all other uses of PFASs. The concept of essential use can also be applied in the management of other chemicals, or groups of chemicals, of concern.

  • 165.
    Cousins, Ian T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ng, Carla A.
    Wang, Zhanyun
    Scheringer, Martin
    Why is high persistence alone a major cause of concern?2019Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, nr 5, s. 781-792Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Persistence is a hazard criterion for chemicals enshrined in chemical regulation worldwide. In this paper, we argue that the higher the persistence of a chemical, the greater the emphasis that it should be given in chemicals assessment and decision making. We provide case studies for three classes of highly persistent chemicals (chlorofluorocarbons, polychlorinated biphenyls, and per-and polyfluoroalkyl substances) to exemplify problems unique to highly persistent chemicals, despite their otherwise diverse properties. Many well-known historical chemical pollution problems were the result of the release of highly persistent chemicals. Using evaluative modeling calculations, we demonstrate that if a chemical is highly persistent, its continuous release will lead to continuously increasing contamination irrespective of the chemical's physical-chemical properties. We argue that these increasing concentrations will result in increasing probabilities of the occurrence of known and unknown effects and that, once adverse effects are identified, it will take decades, centuries or even longer to reverse contamination and therefore effects. Based on our findings we propose that high persistence alone should be established as a sufficient basis for regulation of a chemical, which we term the P-sufficient approach. We argue that regulation on high persistence alone is not over-precautionary given the historical and ongoing problems that persistent chemicals have caused. Regulation of highly persistent chemicals, for example by restriction of emissions, would not only be precautionary, but would serve to prevent poorly reversible future impacts.

  • 166.
    Cousins, Ian T.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vestergren, Robin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Wang, Zhanyun
    Scheringer, Martin
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    The precautionary principle and chemicals management: The example of perfluoroalkyl acids in groundwater2016Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 94, s. 331-340Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Already in the late 1990s microgram-per-liter levels of perfluorooctane sulfonate (PFOS) were measured in water samples from areas where fire-fighting foams were used or spilled. Despite these early warnings, the problems of groundwater, and thus drinking water, contaminated with perfluoroalkyl and polyfluoroalkyl substances (PFASs) including PFOS are only beginning to be addressed. It is clear that this PFAS contamination is poorly reversible and that the societal costs of clean-up will be high. This inability to reverse exposure in a reasonable timeframe is a major motivation for application of the precautionary principle in chemicals management. We conclude that exposure can be poorly reversible; 1) due to slow elimination kinetics in organisms, or 2) due to poorly reversible environmental contamination that leads to continuous exposure. In the second case, which is relevant for contaminated groundwater, the reversibility of exposure is not related to the magnitude of a chemical's bioaccumulation potential. We argue therefore that all PFASs entering groundwater, irrespective of their perfluoroalkyl chain length and bioaccumulation potential, will result in poorly reversible exposures and risks as well as further clean-up costs for society. To protect groundwater resources for future generations, society should consider a precautionary approach to chemicals management and prevent the use and release of highly persistent and mobile chemicals such as PFASs. (C) 2016 Elsevier Ltd. All rights reserved.

  • 167. Croft, B.
    et al.
    Wentworth, G. R.
    Martin, R. V.
    Leaitch, W. R.
    Murphy, J. G.
    Murphy, Benjamin N.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. U.S. Environmental Protection Agency, USA.
    Kodros, J. K.
    Abbatt, J. P. D.
    Pierce, J. R.
    Contribution of Arctic seabird-colony ammonia to atmospheric particles and cloud-albedo radiative effect2016Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 7, artikel-id 13444Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic region is vulnerable to climate change and able to affect global climate. The summertime Arctic atmosphere is pristine and strongly influenced by natural regional emissions, which have poorly understood climate impacts related to atmospheric particles and clouds. Here we show that ammonia from seabird-colony guano is a key factor contributing to bursts of newly formed particles, which are observed every summer in the near-surface atmosphere at Alert, Nunavut, Canada. Our chemical-transport model simulations indicate that the pan-Arctic seabird-influenced particles can grow by sulfuric acid and organic vapour condensation to diameters sufficiently large to promote pan-Arctic cloud-droplet formation in the clean Arctic summertime. We calculate that the resultant cooling tendencies could be large (about -0.5Wm(-2) pan-Arctic-mean cooling), exceeding -1Wm(-2) near the largest seabird colonies due to the effects of seabird-influenced particles on cloud albedo. These coupled ecological-chemical processes may be susceptible to Arctic warming and industrialization.

  • 168. Croft, Betty
    et al.
    Martin, Randall V.
    Leaitch, W. Richard
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Breider, Thomas J.
    D'Andrea, Stephen D.
    Pierce, Jeffrey R.
    Processes controlling the annual cycle of Arctic aerosol number and size distributions2016Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, nr 6, s. 3665-3682Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Measurements at high-Arctic sites (Alert, Nunavut, and Mt. Zeppelin, Svalbard) during the years 2011 to 2013 show a strong and similar annual cycle in aerosol number and size distributions. Each year at both sites, the number of aerosols with diameters larger than 20 nm exhibits a minimum in October and two maxima, one in spring associated with a dominant accumulation mode (particles 100 to 500 nm in diameter) and a second in summer associated with a dominant Aitken mode (particles 20 to 100 nm in diameter). Seasonal-mean aerosol effective diameter from measurements ranges from about 180 in summer to 260 nm in winter. This study interprets these annual cycles with the GEOS-Chem-TOMAS global aerosol microphysics model. Important roles are documented for several processes (new-particle formation, coagulation scavenging in clouds, scavenging by precipitation, and transport) in controlling the annual cycle in Arctic aerosol number and size. Our simulations suggest that coagulation scavenging of interstitial aerosols in clouds by aerosols that have activated to form cloud droplets strongly limits the total number of particles with diameters less than 200 nm throughout the year. We find that the minimum in total particle number in October can be explained by diminishing new-particle formation within the Arctic, limited transport of pollution from lower latitudes, and efficient wet removal. Our simulations indicate that the summertime-dominant Aitken mode is associated with efficient wet removal of accumulation-mode aerosols, which limits the condensation sink for condensable vapours. This in turn promotes new-particle formation and growth. The dominant accumulation mode during spring is associated with build up of transported pollution from outside the Arctic coupled with less-efficient wet-removal processes at colder temperatures. We recommend further attention to the key processes of new-particle formation, interstitial coagulation, and wet removal and their delicate interactions and balance in size-resolved aerosol simulations of the Arctic to reduce uncertainties in estimates of aerosol radiative effects on the Arctic climate.

  • 169. Cui, Xinjuan
    et al.
    Wang, Xinfeng
    Yang, Lingxiao
    Chen, Bing
    Chen, Jianmin
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Radiative absorption enhancement from coatings on black carbon aerosols2016Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 551, s. 51-56Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The radiative absorption enhancement of ambient black carbon (BC), by light-refractive coatings of atmospheric aerosols, constitutes a large uncertainty in estimates of climate forcing. The direct measurements of radiative absorption enhancement require the experimentally-removing the coating materials in ambient BC-containing aerosols, which remains a challenge. Here, the absorption enhancement of the BC core by non-absorbing aerosol coatings was quantified using a two-step removal of both inorganic and organic matter coatings of ambient aerosols. The mass absorption cross-section (MAC) of decoated/pure atmospheric BC aerosols of 4.4 +/- 0.8 m(2)g(-1) was enhanced to 9.6 +/- 1.8 m(2)g(-1) at 678-nm wavelength for ambiently-coated BC aerosols at a rural Northern China site. The enhancement of MAC (E-MAC) rises from 1.4 +/- 0.3 in fresh combustion emissions to similar to 3 for aged ambient China aerosols. The three-week high-intensity campaign observed an average E-MAC of 2.25 +/- 0.55, and sulfates were primary drivers of the enhanced BC absorption.

  • 170.
    Dahlberg, Anna-Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Environmentally relevant chemical disruptors of oxidative phosphorylation in Baltic Sea biota: Exposure and toxic potentials2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis focuses on toxicity and occurrence of hydroxylated polybrominated diphenyl ethers (OH-PBDEs) in Baltic Sea biota. The aims were to assess OH-PBDEs potency for disruption of oxidative phosphorylation (OXPHOS) and determine their and related compounds exposure in Baltic blue mussel, herring and long-tailed duck. A method for analysis of OH-PBDEs in herring and long-tailed duck plasma was also evaluated.

    Relevant OH-PBDEs were tested in vitro for OXPHOS disruption, using a classic rat mitochondrial respiration assay and a cell mitochondrial membrane potential assay. All compounds were found to disrupt OXPHOS either by protonophoric uncoupling and/or via inhibition of the electron transport chain. 6-OH-BDE47 and 6-OH-BDE85, were identified as particularly potent OXPHOS disruptors. Strong synergism was observed when OH-PBDEs were tested as a mixture corresponding to what is present in Baltic blue mussels.

    Baltic blue mussel is main feed for several species of mussel feeding sea ducks which have decreased dramatically in numbers. To assess long-tailed ducks exposure to brominated substances, liver tissue from long-tailed ducks wintering in the Baltic Sea and blue mussels were analysed. The result confirms that long-tailed duck are exposed to OH-PBDEs via their diet. However, low concentrations were found in the duck livers, which suggest low retention of these compounds despite daily intake. How the nutritional value of blue mussels as feed for sea ducks are affected by OH-PBDE exposure still needs further studies. Other species of sea ducks foraging on Baltic blue mussels during summer months can also be more exposed due to seasonal variation in primary production.

    Herring sampled in the Baltic Proper and Bothnian Sea, were found to contain OH-PBDEs and high levels of their methylated counterpart, MeO-PBDEs. As demethylation of MeO-PBDEs is known to occur in fish, MeO-PBDEs may pose as additional source for more toxic OH-PBDEs in herring and their roe.

  • 171.
    Dahlberg, Anna-Karin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Legradi, Jessica
    Legler, Juliette
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Anthropogenic and naturally produced brominated substances in Baltic herring (Clupea harengus) from two sites in the Baltic SeaManuskript (preprint) (Övrigt vetenskapligt)
  • 172.
    Dahlberg, Anna-Karin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Legradi, Jessica
    Legler, Juliette
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Anthropogenic and naturally produced brominated substances in Baltic herring (Clupea harengus membras) from two sites in the Baltic Sea2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 144, s. 2408-2414Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the eutrophicated Baltic Sea, several naturally produced hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been found in marine biota. OH-PBDEs are toxic to adult and developing zebrafish and shown to be potent disruptors of oxidative phosphorylation (OXPHOS). Disturbed OXPHOS can result in altered energy metabolism and weight loss. In herring, the concentration of OH-PBDEs (i.e. 2'-OH-BDE68 and 6-OH-BDE47) has increased during the period 1980-2010 in the Baltic Proper. Over the same time period, the condition and fat content in Baltic herring have decreased. Given the toxicity and increasing trends of OH-PBDEs in Baltic herring it is important to further assess the exposure to OH-PBDEs in Baltic herring. In this study, the concentrations of OH-PBDEs and related brominated substances i.e. polybrominated phenols (PBPs), polybrominated anisoles (PBAs), methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and polybrominated diphenyl ethers (PBDEs) were measured in herring sampled in the northern Baltic Proper (Asko, n = 12) and the southern Bothnian Sea (Angskarsklubb, n = 12). The geometric mean (GM) concentrations (ng/g l.w.) at Asko and Angskarsklubb were; Sigma(2)PBPs: 4.3 and 9.6, Sigma 2PBAs: 34 and 20, Sigma 6OH-PBDEs: 9.4 and 10, Sigma 7MeO-PBDEs: 42 and 150, Sigma 6PBDEs: 54 and 27, respectively. 6-OH-BDE47 dominated the OH-PBDE profile and comprised 87% (Asko) and 91% (Angskarsklubb) of the Sigma OH-PBDEs. At Angskarsklubb the mean concentration of Sigma MeO-PBDEs (150 ng/g l.w.) was 15 times higher than Sigma OH-PBDEs. As other fish species are known to metabolically transform MeO-PBDEs to OH-PBDEs, high levels of MeO-PBDEs can be of concern as a precursor for more toxic OH-PBDEs in herring and their roe.

  • 173.
    Dahlberg, Anna-Karin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindberg Chen, Vivian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Larsson, Kjell
    Bergman, Åke
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hydroxylated and methoxylated polybrominated diphenyl ethers in long-tailed duck (Clangula hyemalis) and their main food, Baltic blue mussel (Mytilus trossulus x Mytilus edulis)Manuskript (preprint) (Övrigt vetenskapligt)
  • 174.
    Dahlberg, Anna-Karin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindberg Chen, Vivian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Larsson, Kjell
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish Toxicology Sciences Research Center (Swetox), Sweden.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hydroxylated and methoxylated polybrominated diphenyl ethers in long-tailed ducks (Clangula hyemalis) and their main food, Baltic blue mussels (Mytilus trossulus x Mytilus edulis).2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 144, s. 1475-1483Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Long-tailed ducks (Clangula hyemalis) that breed in northern Europe and western Siberia and commonly winter in the Baltic Sea, are threatened by a significant population decrease. The ducks are, by primarily feeding on Baltic blue mussels (Mytilus trossulus x Mytilus edulis) while wintering in the Baltic Sea, potentially subjected to high levels of toxic hydroxylated polybrominated diphenyl ethers (OH-PBDEs). To assess long-tailed ducks exposure to polybrominated phenols (PBPs), polybrominated anisoles (PBAs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs), their methylated counterparts (MeO-PBDEs) and polybrominated diphenyl ethers (PBDEs), livers of ten long-tailed ducks wintering in the Baltic Sea were analysed. Pattern and levels of analytes in long-tailed ducks (liver) and blue mussels sampled in March and May at nine sites in the Baltic Sea were compared. The geometric mean concentration (ng/g l.w.) in livers of long-tailed ducks and Baltic blue mussels were: Sigma(2)PBPs: 0.57 and 48; Sigma 2PBAs: 0.83 and 11; Sigma 7OH-PBDEs: 6.1 and 45; Sigma 7MeO-PBDEs: 3.8 and 69; Sigma 7PBDEs: 8.0 and 7.2, respectively. Based on an estimated daily intake of 450 g fresh blue mussel meat, long-tailed ducks daily dietary intake of brominated substances while foraging in the Baltic Sea in March-May was estimated to; 390 ng Sigma(2)PBPs, 90 ng Sigma 2PBAs, 370 ng Sigma 7OH-PBDEs, 590 ng Sigma 7MeO-PBDEs and 59 ng Sigma 7PBDEs. The low levels of PBPs, PBAs, OH-PBDEs and MeO-PBDEs in the long-tailed duck livers compared to blue mussel, despite a continuous daily intake, suggest that these compounds are poorly retained in long-tailed ducks.

  • 175.
    Dahlgren, Elin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Enhus, Carolina
    Lindqvist, Dennis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Induced production of brominated aromatic compounds in the alga Ceramium tenuicorne2015Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 22, nr 22, s. 18107-18114Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the Baltic Sea, high concentrations of toxic brominated aromatic compounds have been detected in all compartments of the marine food web. A growing body of evidence points towards filamentous algae as a natural producer of these chemicals. However, little is known about the effects of environmental factors and life history on algal production of brominated compounds. In this study, several congeners of methoxylated polybrominated diphenyl ethers (MeO-PBDEs), hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and brominated phenols (BPs) were identified in a naturally growing filamentous red algal species (Ceramium tenuicorne) in the Baltic Sea. The identified substances displayed large seasonal variations in the alga with a concentration peak in July. Production of MeO-/OH-PBDEs and BPs by C. tenuicorne was also established in isolated clonal material grown in a controlled laboratory setting. Based on three replicates, herbivory, as well as elevated levels of light and salinity in the culture medium, significantly increased the production of 2,4,6-tribromophenol (2,4,6-TBP). Investigation of differences in production between the isomorphic female, male and diploid clonal life stages of the alga grown in the laboratory revealed a significantly higher production of 2,4,6-TBP in the brackish water female gametophytes, compared to the corresponding marine gametophytes. Even higher concentrations of 2,4,6-TBP were produced by marine male gametophytes and sporophytes.

  • 176. Dahlgren, Elin
    et al.
    Lindqvist, Dennis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Dahlgren, Henrik
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lehtila, Kari
    Trophic transfer of naturally produced brominated aromatic compounds in a Baltic Sea food chain2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 144, s. 1597-1604Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Brominated aromatic compounds (BACs) are widely distributed in the marine environment. Some of these compounds are highly toxic, such as certain hydroxylated polybrominated diphenyl ethers (OH-PBDEs). In addition to anthropogenic emissions through use of BACs as e.g. flame retardants, BACs are natural products formed by marine organisms such as algae, sponges, and cyanobacteria. Little is known of the transfer of BACs from natural producers and further up in the trophic food chain. In this study it was observed that total sum of methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and OH-PBDEs increased in concentration from the filamentous red alga Ceramium tenuicorne, via Gammarus sp. and three-spined stickleback (Gasterosteus aculeatus) to perch (Perca fluviatilis). The MeO-PBDEs, which were expected to bioaccumulate, increased in concentration accordingly up to perch, where the levels suddenly dropped dramatically. The opposite pattern was observed for OH-PBDEs, where the concentration exhibited a general trend of decline up the food web, but increased in perch, indicating metabolic demethylation of MeO-PBDEs. Debromination was also indicated to occur when progressing through the food chain resulting in high levels of tetra-brominated MeO-PBDE and OH-PBDE congeners in fish, while some penta- and hexa-brominated congeners were observed to be the dominant products in the alga. As it has been shown that OH-PBDEs are potent disruptors of oxidative phosphorylation and that mixtures of different congener may act synergistically in terms of this toxic mode of action, the high levels of OH-PBDEs detected in perch in this study warrants further investigation into potential effects of these compounds on Baltic wildlife, and monitoring of their levels.

  • 177.
    Dahlgren Strååt, Kim
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Simulating Transport and Understanding Future Fluxes of Organic Carbon in Rivers Draining into the Baltic Sea2017Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Riverine organic (TOC, Total Organic Carbon) and inorganic (DIC, Dissolved Inorganic Carbon) carbon are the main sources of carbon in the Baltic Sea. While the importance of this contribution has been evaluated, there are currently several gaps in our knowledge of the mechanisms governing organic carbon dynamics in this region, especially for the particulate form, and the impact of future climate change on organic carbon transport. This licentiate thesis addresses this research deficit by (1) developing a model for assessing the flux of particulate organic carbon (POC), and by (2) simulating the potential climate effects on the transport and fate of TOC, both particulate and dissolved organic carbon, in the Baltic Sea environment.

    Study I developed a novel dynamic model for simulating the generation and transport of POC in all the major rivers discharging into the Baltic Sea. The POC load was assessed using algorithms for the processes governing the input i.e. erosion, litterfall and in-stream primary production. Using daily information on precipitation and temperature, the water discharge from each river was calculated. The total annual POC load from the Baltic Sea drainage basin was predicted within a factor of about 2 and was estimated to be 0.34 Tg POC, or 7-10 % of the annual TOC. The prediction of the timing of the monthly peak loads, however, was hampered by the current lack of field measurements of POC loads to the Baltic Sea.

    Study II assessed the potential future climate effects on riverine TOC (particulate and dissolved organic carbon, DOC) in the Baltic Sea drainage basin. A small decrease in POC load (-7 %) was predicted and no changes in DOC load on an annual and total basin scale, but the simulations showed significant variations between seasons and across sub-basins by the end of this century. Seasonal total loads were predicted to increase in winter and decrease in summer. Due to counterbalancing increases and decreases in predicted TOC loads in various parts of the Baltic Sea catchment, the impact of climate change on the total carbon budget in this region was limited. However, our simulation results indicated significant differences over time in POC and DOC export across the six Baltic Sea sub-basins, and an altered seasonal pattern in the timing and magnitude of the delivery.

    This thesis comprises a first attempt to better describe the mechanisms and dynamics of OC generation and transport in the Baltic Sea catchment and assess the potential climate effects on the transport with a spatiotemporal resolution. The work provides a starting point for further development of the understanding of large scale organic carbon export and how it may be affected in the future. This thesis also discuss the role of riverine organic carbon in biogeochemical processes, food web structures and contaminant transport in inland, coastal and marine waters.

  • 178.
    Dahlgren Strååt, Kim
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Smedberg, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Modeling total particulate organic carbon (POC) flows in the Baltic Sea catchment2016Ingår i: Biogeochemistry, ISSN 0168-2563, E-ISSN 1573-515X, Vol. 128, nr 1-2, s. 51-65Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The largest input source of carbon to the Baltic Sea catchment is river discharge. A tool for modeling riverine particulate organic carbon (POC) loads on a catchment scale is currently lacking. The present study describes a novel dynamic model for simulating flows of POC in all major rivers draining the Baltic Sea catchment. The processes governing POC input and transport in rivers described in the model are soil erosion, in-stream primary production and litter input. The Baltic Sea drainage basin is divided into 82 sub-basins, each comprising several land classes (e.g. forest, cultivated land, urban areas) and parameterized using GIS data on soil characteristics and topography. Driving forces are temperature, precipitation, and total phosphorous concentrations. The model evaluation shows that the model can predict annual average POC concentrations within a factor of about 2, but generally fails to capture the timing of monthly peak loads. The total annual POC load to the Baltic Sea is estimated to be 0.34 Tg POC, which constitutes circa 7-10 % of the annual total organic carbon (TOC) load. The current lack of field measurements of POC in rivers hampers more accurate predictions of seasonality in POC loads to the Baltic Sea. This study, however, identifies important knowledge gaps and provides a starting point for further explorations of large scale POC mass flows.

  • 179.
    Dahlgren Strååt, Kim
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mörth, Carl-Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum.
    Future export of particulate and dissolved organic carbon from land to coastal zones of the Baltic Sea2018Ingår i: Journal of Marine Systems, ISSN 0924-7963, E-ISSN 1879-1573, Vol. 177, s. 8-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Baltic Sea is a semi-enclosed brackish sea in Northern Europe with a drainage basin four times larger than the sea itself. Riverine organic carbon (Particulate Organic Carbon, POC and Dissolved Organic Carbon, DOC) dominates carbon input to the Baltic Sea and influences both land-to-sea transport of nutrients and contaminants, and hence the functioning of the coastal ecosystem. The potential impact of future climate change on loads of POC and DOC in the Baltic Sea drainage basin (BSDB) was assessed using a hydrological-biogeochemical model (CSIM). The changes in annual and seasonal concentrations and loads of both POC and DOC by the end of this century were predicted using three climate change scenarios and compared to the current state. In all scenarios, overall increasing DOC loads, but unchanged POC loads, were projected in the north. In the southern part of the BSDB, predicted DOC loads were not significantly changing over time, although POC loads decreased in all scenarios. The magnitude and significance of the trends varied with scenario but the sign (+ or -) of the projected trends for the entire simulation period never conflicted. Results were discussed in detail for the middle CO2 emission scenario (business as usual, a1b). On an annual and entire drainage basin scale, the total POC load was projected to decrease by ca 7% under this scenario, mainly due to reduced riverine primary production in the southern parts of the BSDB. The average total DOC load was not predicted to change significantly between years 2010 and 2100 due to counteracting decreasing and increasing trends of DOC loads to the six major sub-basins in the Baltic Sea. However, predicted seasonal total loads of POC and DOC increased significantly by ca 46% and 30% in winter and decreased by 8% and 21% in summer over time, respectively. For POC the change in winter loads was a consequence of increasing soil erosion and a shift in duration of snowfall and onset of the spring flood impacting the input of terrestrial litter, while reduced primary production mainly explained the differences predicted in summer. The simulations also showed that future changes in POC and DOC export can vary significantly across the different sub-basins of the Baltic Sea. These changes in organic carbon input may impact future coastal food web structures e.g. by influencing bacterial and phytoplankton production in coastal zones, which in turn may have consequences at higher trophic levels.

  • 180.
    Dalirian, Maryam
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Investigating parameters governing liquid-phase cloud activation of atmospheric particles2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Aerosol-cloud interactions are one of the main sources of uncertainties in modeling and predicting the Earth’s climate. To overcome this uncertainty, we need to improve the understanding about the processes and parameters defining how aerosol particles turn into cloud condensation nuclei (CCN) or ice nuclei (IN) to produce cloud droplets or ice crystals. The focus of this dissertation is on liquid phase cloud droplets. The thesis investigates the effect of water solubility and surface tension on the CCN activity of atmospheric aerosol particles. These parameters are among the key properties defining how an aerosol particle can turn into a cloud droplet. The main goals of this thesis are to investigate 1) the CCN activity of aerosol particles containing both water soluble and insoluble substances and 2) the contribution of molecular-scale surface structure to the surface tension and CCN activity of atmospherically relevant aqueous mixtures.

    In the first part of this thesis, the CCN activity of water-insoluble aerosol constituents coated by water-soluble or sparingly soluble species was investigated. The results showed that the CCN activity of the insoluble silica and black carbon particles, with sizes between 100 and 300 nm, increased with the amount of the coating on the insoluble cores and at thick enough coating approached the CCN activity of the soluble species. Moreover, controlled dry coating of the insoluble BC cores yielded a size-independent distribution of the coating material on the insoluble cores, which was not achieved by wet coating of the silica particles. The results also confirmed that by knowing the fraction of soluble material (coating thicknesses), the existing theories gave a reasonable estimate of the CCN activity for the mixed soluble-insoluble particles. Finally, the results highlight the need for including the impacts of co-emitted or later condensed compounds in estimates of the climate impacts of atmospheric insoluble aerosol species.

    In the second part of the thesis, surface propensity of succinic acid, pure or mixed with soluble inorganic salts in the aqueous droplets, were quantified via molecular-level surface composition measurement by X-ray Photoelectron Spectroscopy (XPS). The XPS and molecular dynamic (MD) simulations of succinic acid aqueous solutions showed strong enrichment of the succinic acid at the surface of the liquid droplets compared to the bulk solution. This effect was more pronounced in the presence of the highly soluble inorganic salts like NaCl and (NH4)2SO4 in the system. The modeled surface tension of the pure organic or mixture of organic and inorganic substances, using surface enrichment factors derived from the XPS experiments were in good agreement with the experimental surface tension data. This demonstrates the high potential of XPS for direct measurements of the surface composition of atmospherically relevant aqueous mixtures. The results suggest that for modeling the phase-state and water content of the atmospheric particles, the contribution by the surface layer needs to be considered, because aqueous droplet can contain larger amounts of organic compounds than the bulk solubility limit of the solutions. However, the effect of the aqueous surface composition on the CCN activation of particles consisting of the studied mixtures was estimated to be very small.

    The results presented in this thesis provide new insights into the relationship between aerosol particle composition and cloud condensation nuclei activity. However, the effect of more realistic complex mixtures will require more research. The results showed that for modeling semi-volatile species, the partitioning between the gas and condensed phase needs to be considered. In addition, along with the liquid-phase cloud activation, the ice nucleation ability of the particles made of soluble and insoluble species requires to be further investigated.

  • 181.
    Dalirian, Maryam
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Keskinen, H.
    Ahlm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ylisirniö, A.
    Romakkaniemi, S.
    Laaksonen, A.
    Virtanen, A.
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    CCN activation of fumed silica aerosols mixed with soluble pollutants2015Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, nr 7, s. 3815-3829Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Particle-water interactions of completely soluble or insoluble particles are fairly well understood but less is known of aerosols consisting of mixtures of soluble and insoluble components. In this study, laboratory measurements were performed to investigate cloud condensation nuclei (CCN) activity of silica particles mixed with ammonium sulfate (a salt), sucrose (a sugar) and bovine serum albumin known as BSA (a protein). The agglomerated structure of the silica particles was investigated using measurements with a differential mobility analyser (DMA) and an aerosol particle mass analyser (APM). Based on these data, the particles were assumed to be compact agglomerates when studying their CCN activation capabilities. Furthermore, the critical super-saturations of particles consisting of pure and mixed soluble and insoluble compounds were explored using existing theoretical frameworks. These results showed that the CCN activation of single-component particles was in good agreement with Kohler- and adsorption theory based models when the agglomerated structure was accounted for. For mixed particles the CCN activation was governed by the soluble components, and the soluble fraction varied considerably with particle size for our wet-generated aerosols. Our results confirm the hypothesis that knowing the soluble fraction is the key parameter needed for describing the CCN activation of mixed aerosols, and highlight the importance of controlled coating techniques for acquiring a detailed understanding of the CCN activation of atmospheric insoluble particles mixed with soluble pollutants.

  • 182.
    Dalirian, Maryam
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ylisirniö, Arttu
    Buchholz, Angela
    Schlesinger, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Virtanen, Annele
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Cloud droplet activation of black carbon particles coated with organic compounds of varying solubility2018Ingår i: Atmospheric Chemistry and Physics Discussions, ISSN 1680-7367, E-ISSN 1680-7375, Vol. 18, nr 16, s. 12477-12489Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Atmospheric black carbon (BC) particles are a concern due to their impact on air quality and climate. Their net climate effect 15 is, however, still uncertain. This uncertainty is partly related to the contribution of coated BC-particles to the global CCN budgets. In this study, laboratory measurements were performed to investigate cloud condensation nuclei (CCN) activity of BC (Regal black) particles, in pure state or coated through evaporating and subsequent condensation of glutaric acid, levoglucosan (both water-soluble organics) or oleic acid (an organic compound with low solubility). A combination of Soot Particle Aerosol Mass Spectrometer (SP-AMS) measurements and size distribution measurements with Scanning Mobility 20 Particle Sizer (SMPS) showed that the studied BC particles were nearly spherical agglomerates with a fractal dimension of 2.79 and that they were coated evenly by the organic species. The CCN activity of BC particles increased after coating with all the studied compounds and was governed by the fraction of organic material. The CCN activation of the BC particles coated by glutaric acid and levoglucosan were in good agreement with the theoretical calculations using shell-and-core model, which is based on a combination of the CCN activities of the pure compounds. The oleic acid coating enhanced the CCN 25 activity of the BC particles, even though the pure oleic acid particles were CCN inactive. The surprising effect of oleic acid might be related to the arrangement of the oleic acid molecules on the surface of the BC cores or other surface phenomena facilitating water condensation onto the coated particles. Our results show potential in accurately predicting the CCN activity of atmospheric BC coated with organic species by present theories, given that the identities and amount of the coating species are known. Furthermore, our results suggest that even relatively thin soluble coatings (around 2 nm for the compounds studied here) are enough to make the insoluble BC particles CCN active at typical atmospheric supersaturations and thus be efficiently taken up by cloud droplets. This highlights the need of an accurate description of the composition of atmospheric particles containing BC to unravel their net impact on climate.

  • 183. Dall' Osto, M.
    et al.
    Beddows, D. C. S.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hansson, Hans-Christen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yoon, Y. J.
    Park, Ki-Tae
    Becagli, S.
    Udisti, R.
    Onasch, T.
    O'Dowd, C. D.
    Simo, R.
    Harrison, Roy M.
    Arctic sea ice melt leads to atmospheric new particle formation2017Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 7, artikel-id 3318Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Atmospheric new particle formation (NPF) and growth significantly influences climate by supplying new seeds for cloud condensation and brightness. Currently, there is a lack of understanding of whether and how marine biota emissions affect aerosol-cloud-climate interactions in the Arctic. Here, the aerosol population was categorised via cluster analysis of aerosol size distributions taken at Mt Zeppelin (Svalbard) during a 11 year record. The daily temporal occurrence of NPF events likely caused by nucleation in the polar marine boundary layer was quantified annually as 18%, with a peak of 51% during summer months. Air mass trajectory analysis and atmospheric nitrogen and sulphur tracers link these frequent nucleation events to biogenic precursors released by open water and melting sea ice regions. The occurrence of such events across a full decade was anti-correlated with sea ice extent. New particles originating from open water and open pack ice increased the cloud condensation nuclei concentration background by at least ca. 20%, supporting a marine biosphere-climate link through sea ice melt and low altitude clouds that may have contributed to accelerate Arctic warming. Our results prompt a better representation of biogenic aerosol sources in Arctic climate models.

  • 184. Dall'Osto, M.
    et al.
    Beddows, D. C. S.
    Asmi, A.
    Poulain, L.
    Hao, L.
    Freney, E.
    Allan, J. D.
    Canagaratna, M.
    Crippa, M.
    Bianchi, F.
    de Leeuw, G.
    Eriksson, A.
    Swietlicki, E.
    Hansson, Hans Christen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Henzing, J. S.
    Granier, C.
    Zemankova, K.
    Laj, P.
    Onasch, T.
    Prevot, A.
    Putaud, J. P.
    Sellegri, K.
    Vidal, M.
    Virtanen, A.
    Simo, R.
    Worsnop, D.
    O'Dowd, C.
    Kulmala, M.
    Harrison, Roy M.
    Novel insights on new particle formation derived from a pan-european observing system2018Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, artikel-id 1482Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The formation of new atmospheric particles involves an initial step forming stable clusters less than a nanometre in size (<similar to 1 nm), followed by growth into quasi-stable aerosol particles a few nanometres (similar to 1-10 nm) and larger (>similar to 10 nm). Although at times, the same species can be responsible for both processes, it is thought that more generally each step comprises differing chemical contributors. Here, we present a novel analysis of measurements from a unique multi-station ground-based observing system which reveals new insights into continental-scale patterns associated with new particle formation. Statistical cluster analysis of this unique 2-year multi-station dataset comprising size distribution and chemical composition reveals that across Europe, there are different major seasonal trends depending on geographical location, concomitant with diversity in nucleating species while it seems that the growth phase is dominated by organic aerosol formation. The diversity and seasonality of these events requires an advanced observing system to elucidate the key processes and species driving particle formation, along with detecting continental scale changes in aerosol formation into the future.

  • 185. Dall'Osto, Manuel
    et al.
    Beddows, David C. S.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Harrison, Roy M.
    Lupi, Angelo
    Vitale, Vito
    Becagli, Silvia
    Traversi, Rita
    Park, Ki-Tae
    Yoon, Young Jun
    Massling, Andreas
    Skov, Henrik
    Lange, Robert
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Simultaneous measurements of aerosol size distributions at three sites in the European high Arctic2019Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 19, nr 11, s. 7377-7395Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Aerosols are an integral part of the Arctic climate system due to their direct interaction with radiation and indirect interaction through cloud formation. Understanding aerosol size distributions and their dynamics is crucial for the ability to predict these climate relevant effects. When of favourable size and composition, both long-rangetransported - and locally formed particles - may serve as cloud condensation nuclei (CCN). Small changes of composition or size may have a large impact on the low CCN concentrations currently characteristic of the Arctic environment. We present a cluster analysis of particle size distributions (PSDs; size range 8-500 nm) simultaneously collected from three high Arctic sites during a 3-year period (20132015). Two sites are located in the Svalbard archipelago: Zeppelin research station (ZEP; 474 m above ground) and the nearby Gruvebadet Observatory (GRU; about 2 km distance from Zeppelin, 67 m above ground). The third site (Villum Research Station at Station Nord, VRS; 30 m above ground) is 600 km west-northwest of Zeppelin, at the tip of northeastern Greenland. The GRU site is included in an inter-site comparison for the first time. K-means cluster analysis pro- vided eight specific aerosol categories, further combined into broad PSD classes with similar characteristics, namely pristine low concentrations (12 %-14 % occurrence), new particle formation (16 %-32 %), Aitken (21 %-35 %) and accumulation (20 %-50 %). Confined for longer time periods by consolidated pack sea ice regions, the Greenland site GRU shows PSDs with lower ultrafine-mode aerosol concentrations during summer but higher accumulation-mode aerosol concentrations during winter, relative to the Svalbard sites. By association with chemical composition and cloud condensation nuclei properties, further conclusions can be derived. Three distinct types of accumulation-mode aerosol are observed during winter months. These are associated with sea spray (largest detectable sizes, > 400 nm), Arctic haze (main mode at 150 nm) and aged accumulation-mode (main mode at 220 nm) aerosols. In contrast, locally produced particles, most likely of marine biogenic origin, exhibit size distributions dominated by the nucleation and Aitken mode during summer months. The obtained data and analysis point towards future studies, including apportioning the relative contribution of primary and secondary aerosol formation processes and elucidating anthropogenic aerosol dynamics and transport and removal processes across the Greenland Sea. In order to address important research questions in the Arctic on scales beyond a singular station or measurement events, it is imperative to continue strengthening international scientific cooperation.

  • 186. D'Ambro, Emma L.
    et al.
    Schobesberger, Siegfried
    Zaveri, Rahul A.
    Shilling, John E.
    Lee, Ben Hwan
    Lopez-Hilfiker, Felipe D.
    Mohr, Claudia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Washington, United States.
    Thornton, Joel A.
    Isothermal Evaporation of alpha-Pinene Ozonolysis SOA: Volatility, Phase State, and Oligomeric Composition2018Ingår i: ACS earth and space chemistry, ISSN 2472-3452, Vol. 2, nr 10, s. 1058-1067Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We present measurements of the isothermal evaporation of alpha-pinee ozonolysis secondary organic aerosol (SOA). Using a novel, filter-based method, we reproduce literature observations of the time-dependent evaporation of SOA particles. We apply two detailed physical models to interpret the evaporative behavior of both the bulk SOA and individual components. Both models find that a combination of effectively nonvolatile products, together with reversibly formed oligomers (or otherwise reactive monomers) having a decomposition lifetime of 9 to 28 h, best explains the evolution of composition and volatility as particles age in the absence of both organic vapors and oxidants, even under an assumption of relatively viscous (soft wax-like with a minimum diffusion coefficient of 1 x 10(-5) cm(2) s(-1)) particles. We find that the residence time in the SOA formation chamber and time spent undergoing isothermal evaporation, both indicative of the physical age of the aerosol, are the most important experimental parameters determining the evaporation rate. The evolution of volatility observed in these experiments is compared to field measurements in a boreal forest site. The ambient monoterpene-dominated SOA volatility is only reproduced in the laboratory after 24 h of extended aging in a dilute, dark, oxidant-free environment.

  • 187.
    Dasari, Sanjeev
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bikkina, Srinivas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmstrand, Henry
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Budhavant, Krishnakant
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Maldives Climate Observatory at Hanimaadhoo (MCOH), Republic of the Maldives; Indian Institute of Sciences (IISC), India.
    Satheesh, Sreedharan
    Asmi, Eija
    Kesti, Jutta
    Backman, John
    Salam, Abdus
    Bisht, Deewan Singh
    Tiwari, Suresh
    Hameed, Zahid
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Photochemical degradation affects the light absorption of water-soluble brown carbon in the South Asian outflow2019Ingår i: Science Advances, E-ISSN 2375-2548, Vol. 5, nr 1, artikel-id eaau8066Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Light-absorbing organic aerosols, known as brown carbon (BrC), counteract the overall cooling effect of aerosols on Earth's climate. The spatial and temporal dynamics of their light-absorbing properties are poorly constrained and unaccounted for in climate models, because of limited ambient observations. We combine carbon isotope forensics (delta C-13) with measurements of light absorption in a conceptual aging model to constrain the loss of light absorptivity (i.e., bleaching) of water-soluble BrC (WS-BrC) aerosols in one of the world's largest BrC emission regions-South Asia. On this regional scale, we find that atmospheric photochemical oxidation reduces the light absorption of WS-BrC by similar to 84% during transport over 6000 km in the Indo-Gangetic Plain, with an ambient first-order bleaching rate of 0.20 +/- 0.05 day(-1) during over-ocean transit across Bay of Bengal to an Indian Ocean receptor site. This study facilitates dynamic parameterization of WS-BrC absorption properties, thereby constraining BrC climate impact over South Asia.

  • 188. de Oliveira Galvão, Marcos Felipe
    et al.
    Sadiktsis, Ioannis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Batistuzzo de Medeiros, Silvia R.
    Dreij, Kristian
    DNA damage signaling and genotoxic effects induced by complex mixtures of PAHs generated by biomass burning air particulate matter in human lung cells2019Ingår i: Toxicology Letters, ISSN 0378-4274, E-ISSN 1879-3169, Vol. 314, nr SI, s. S132-S133Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Most research concerning the effects of air pollutants on human health focuses on urban centers and on the role of vehicular and industrial emissions as major sources of pollution. However, approximately 3 billion people world-wide are exposed to air pollution from biomass burning [1]. Herein, particulate matter (PM) emitted from artisanal cashew nut roasting, an important economic and social activity worldwide [2,3], was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and their oxy-PAH derivatives; ii) time-dependent activation of DNA damage signaling and genotoxic effects, and iii) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8-10 ng/m3), while among oxy-PAHs, benzanthrone and 9,10-anthraquinone were the most abundant. Testing of PM extracts was based on B[a]P equivalent doses (B[a]Peq). IC50 values for viability was 5.7 and 3.0 nM B[a]Peq at 24 h and 48 h, respectively. Based on this, all other experiments were conducted at doses up to 2 nM B[a]Peq. At these low doses, we observed a dose-dependent activation of DNA damage signaling (phosphorylation of Chk1) and genotoxicity (double strand breaks). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no other study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro [4], in lung cells exposed to biomass burning extracts. Persistent increased gene expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), inflammation (IL-8, TNF-α), cell cycle arrest (CDKN1A), and DNA repair (DDB2) was also identified. In conclusion, our data show high potency of biomass burning PM to induce cellular stress including genotoxicity, and more potently so when compared to B[a]P alone. Our study provides new data that will help elucidate the mechanism of lung cancer development associated with biomass burning. In addition, the results of this study support the establishment of new guidelines for human health protection in regions strongly impacted by biomass burning.

  • 189. de Oliveira Galvão, Marcos Felipe
    et al.
    Sadiktsis, Ioannis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Batistuzzo de Medeiros, Silvia Regina
    Dreij, Kristian
    Genotoxicity and DNA damage signaling in response to complex mixtures of PAHs in biomass burning particulate matter from cashew nut roasting2020Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 256, artikel-id 113381Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Approximately 3 billion people world-wide are exposed to air pollution from biomass burning. Herein, particulate matter(PM) emitted from artisanal cashew nut roasting, an important economic activity worldwide, was investigated. This study focused on: i) chemical characterization of polycyclic aromatic hydrocarbons (PAHs) and oxygenated (oxy-) PAHs; ii) intracellular levels of reactive oxygen species (ROS); iii) genotoxic effects and time- and dose-dependent activation of DNA damage signaling, and iv) differential expression of genes involved in xenobiotic metabolism, inflammation, cell cycle arrest and DNA repair, using A549 lung cells. Among the PAHs, chrysene, benzo[a]pyrene (B[a]P), benzo[b]fluoranthene, and benz[a]anthracene showed the highest concentrations (7.8–10 ng/m3), while benzanthrone and 9,10-anthraquinone were the most abundant oxy-PAHs. Testing of PM extracts was based on B[a]P equivalent doses (B[a]Peq). IC50 values for viability were 5.7 and 3.0 nM B[a]Peq at 24 h and 48 h, respectively. At these low doses, we observed a time- and dose-dependent increase in intracellular levels of ROS, genotoxicity (DNA strand breaks) and DNA damage signaling (phosphorylation of the protein checkpoint kinase 1 – Chk1). In comparison, effects of B[a]P alone was observed at micromolar range. To our knowledge, no previous study has demonstrated an activation of pChk1, a biomarker used to estimate the carcinogenic potency of PAHs in vitro, in lung cells exposed to cashew nut roasting extracts. Sustained induction of expression of several important stress response mediators of xenobiotic metabolism (CYP1A1, CYP1B1), ROS and pro-inflammatory response (IL-8, TNF-α, IL-2,COX2), and DNA damage response (CDKN1A and DDB2) was also identified. In conclusion, our data show high potency of cashew nut roasting PM to induce cellular stress including genotoxicity, and more potently when compared to B[a]P alone. Our study provides new data that will help elucidate the toxic effects of low-levels of PAH mixtures from air PM generated by cashew nut roasting.

  • 190.
    de Wit, Cynthia A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Johansson, Anna-Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sellström, Ulla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindberg, Peter
    Mass balance study of brominated flame retardants in female captive peregrine falcons2019Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 21, nr 7, s. 1115-1131Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Little is known about brominated flame retardant (BFR) dynamics in birds, especially large molecules such as decabromodiphenyl ether (BDE-209). In particular, bioaccumulation from food and transfer dynamics to eggs are poorly understood. Therefore, an input-output mass balance study of tri-decaBDEs, DBDPE and HBCDD was performed in three female peregrine falcons from a captive breeding program by analyzing their naturally contaminated food (quail, chicken (cockerels)), plasma, feces and eggs. Predominant BFRs in cockerels and quail were BDE-209 and DBDPE, as well as HBCDD in quail. The predominant BFRs found in falcon plasma were BDE-209, -153 and -183, in eggs, HBCDD, BDE-209 and -153 and in feces, BDE-209. Mean absorption efficiencies (AE) for the tetra-octabrominated BDEs ranged from 84-100% and 70% for HBCDD. The AEs for BDE-206, -207, -208 and -209 varied due to the large variability seen for feces fluxes. All egg/plasma ratios for BDEs were similar and greater than one (range 1.1-2.7), including for BDE-209, indicating efficient transfer from females to the eggs. Excretion via egg-laying was approximately 6.0-29% of the initial, pre-breeding body burden of individual penta-decaBDE congeners, (15-45% for BDE-206). HBCDD was not detected in plasma but was found in eggs, also indicating efficient transfer and excretion via eggs. Input fluxes from food exceeded the output fluxes (feces, eggs) indicating considerable metabolism for tetra-octaBDEs, possibly also for the nona-decaBDEs and HBCDD. Bioaccumulation factors calculated from lipid weight concentrations in plasma and food (BAF(p)) were highest for BDE-208 (31), -153 (23), -209 (19) and -207 (16) and from eggs and food (BAF(e)), were highest for HBCDD (140), BDE-153 (41), -208 (42), BDE-207 (24) and BDE-209 (21). BAF(e) and BAF(p) values were below 10 for BDE-47, -99 and -100. For one falcon, egg results were available from three different years and estimated half-lives were 65 d (BDE-99), 624 d (BDE-153), 31 d (BDE-154), 349 d (BDE-183), 77 d (BDE-196) and 89 d (BDE-197).

  • 191. Degner, Amanda
    et al.
    Carlsson, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlsson, Isabella
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Eriksson, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Pujari, Suresh S.
    Tretyakova, Natalia Y.
    Törnqvist, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Discovery of Novel N-(4-Hydroxybenzyl)valine Hemoglobin Adducts in Human Blood2018Ingår i: Chemical Research in Toxicology, ISSN 0893-228X, E-ISSN 1520-5010, Vol. 31, nr 12, s. 1305-1314Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Humans are exposed to a wide range of electrophilic compounds present in our diet and environment or formed endogenously as part of normal physiological processes. These electrophiles can modify nucleophilic sites of proteins and DNA to form covalent adducts. Recently, powerful untargeted adductomic approaches have been developed for systematic screening of these adducts in human blood. Our earlier untargeted adductomics study detected 19 unknown adducts to N-terminal valine in hemoglobin (Hb) in human blood. We now describe a full characterization of one of these adducts, which corresponds to the addition of a 4-hydroxybenzyl (4-OHBn) group to N-terminal valine in Hb to form N(4-hydroxybenzyl)valine (4-OHBn-Val). The adduct structure was determined by comparison of its accurate mass, HPLC retention time, and MS/MS fragmentation to that of authentic standards prepared by chemical synthesis. Average 4-OHBn-Val adduct concentrations in 12 human blood samples were estimated to 380 +/- 160 pmol/g Hb. Two possible routes of 4-OHBnVal adduct formation are proposed using two different precursor electrophiles: 4-quinone methide (4-QM) and 4-hydroxybenzaldehyde (4-OHBA). We found that 4-QM reacts rapidly with valine to form the 4-OHBn-Val adduct; however, the quinone methide is unstable under physiological conditions due to hydrolysis. It was shown that 4-OHBA forms reversible Schiff base adducts with valine, which can be stabilized via reduction in blood generating the 4-OHBn-Val adduct. In addition, trace amounts of isomeric 2-hydroxybenzyl-valine (2-OHBn-Val) adducts were detected in 12 human blood samples (estimated mean adduct level, 5.0 +/- 1.4 pmol/g Hb). Further studies are needed to quantify the contributions from identified possible precursor electrophiles to the observed hydroxybenzyl adducts in humans.

  • 192. Denby, B. R.
    et al.
    Ketzel, M.
    Ellermann, T.
    Stojiljkovic, A.
    Kupiainen, K.
    Niemi, J. V.
    Norman, M.
    Johansson, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Environment and Health Protection Administration of the City of Stockholm, Sweden.
    Gustafsson, M.
    Blomqvist, G.
    Janhall, S.
    Sundvor, I.
    Road salt emissions: A comparison of measurements and modelling using the NORTRIP road dust emission model2016Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 141, s. 508-522Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    De-icing of road surfaces is necessary in many countries during winter to improve vehicle traction. Large amounts of salt, most often sodium chloride, are applied every year. Most of this salt is removed through drainage or traffic spray processes but a certain amount may be suspended, after drying of the road surface, into the air and will contribute to the concentration of particulate matter. Though some measurements of salt concentrations are available near roads, the link between road maintenance salting activities and observed concentrations of salt in ambient air is yet to be quantified. In this study the NORTRIP road dust emission model, which estimates the emissions of both dust and salt from the road surface, is applied at five sites in four Nordic countries for ten separate winter periods where daily mean ambient air measurements of salt concentrations are available. The model is capable of reproducing many of the salt emission episodes, both in time and intensity, but also fails on other occasions. The observed mean concentration of salt in PM10, over all ten datasets, is 4.2 mu g/m(3) and the modelled mean is 2.8 mu g/m(3), giving a fractional bias of -0.38. The RMSE of the mean concentrations, over all 10 datasets, is 2.9 mu g/m(3) with an average R-2 of 0.28. The mean concentration of salt is similar to the mean exhaust contribution during the winter periods of 2.6 mu g/m(3). The contribution of salt to the kerbside winter mean PM10 concentration is estimated to increase by 4.1 +/- 3.4 mu g/m(3) for every kg/m(2) of salt applied on the road surface during the winter season. Additional sensitivity studies showed that the accurate logging of salt applications is a prerequisite for predicting salt emissions, as well as good quality data on precipitation. It also highlights the need for more simultaneous measurements of salt loading together with ambient air concentrations to help improve model parameterisations of salt and moisture removal processes.

  • 193. Derakhshan, Arash
    et al.
    Shu, Huan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Broeren, Maarten A. C.
    de Poortere, Ralph A.
    Wikström, Sverre
    Peeters, Robin P.
    Demeneix, Barbara
    Bornehag, Carl-Gustaf
    Korevaar, Tim I. M.
    Reference Ranges and Determinants of Thyroid Function During Early Pregnancy: The SELMA Study2018Ingår i: Journal of Clinical Endocrinology and Metabolism, ISSN 0021-972X, E-ISSN 1945-7197, Vol. 103, nr 9, s. 3548-3556Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Context: Establishing reference ranges as well as identifying and quantifying the determinants of thyroid function during pregnancy is important for proper clinical interpretation and optimizing research efforts. However, such data are sparse, specifically for triiodothyronine measurements, and most studies do not take into account thyroid antibodies or human chorionic gonadotropin.

    Objective: To determine reference ranges and to identify/quantify determinants of TSH, free T4 (FT4), free triiodothyronine (FT3), total T4 (TT4), and total triiodothyronine (TT3).

    Design, Setting, and Participants: This study included 2314 participants of the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy study, a population-based prospective pregnancy cohort of mother-child pairs. Reference ranges were calculated by 2.5th to 97.5th percentiles after excluding thyroperoxidase antibody (TPOAb)-positive and/or thyroglobulin antibody (TgAb)-positive women.

    Intervention: None.

    Main Outcome Measures: TSH, FT4, FT3, TT4, and TT3 in prenatal serum.

    Results: After exclusion of TPOAb-positive women, reference ranges were as follows: TSH, 0.11 to 3.48 mU/L; FT4, 11.6 to 19.4 pmol/L; FT3, 3.72 to 5.92 pg/mL; TT4, 82.4 to 166.2 pmol/L; and TT3, 1.28 to 2.92 nmol/L. Additional exclusion of TgAb-positive women did not change the reference ranges substantially. Exposure to tobacco smoke, as assessed by questionnaires and serum cotinine, was associated with lower TSH and higher FT3 and TT3. Body mass index (BMI) and gestational age were the main determinants of TSH (only for BMI), FT4, FT3, TT4, and TT3.

    Conclusions: We show that the exclusion of TgAb-positive women on top of excluding TPOAb-positive women hardly affects clinical reference ranges. We identified various relevant clinical determinants of TSH, FT4, FT3, TT4, and TT3 that could reflect endocrine-disrupting effects and/or effects on thyroid hormone transport or deiodination.

  • 194. Derakhshan, Arash
    et al.
    Shu, Huan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Peeters, Robin P.
    Kortenkamp, Andreas
    Lindh, Christian H.
    Demeneix, Barbara
    Bornehag, Carl-Gustaf
    Korevaar, Tim I. M.
    Association of urinary bisphenols and triclosan with thyroid function during early pregnancy2019Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 133, artikel-id 105123Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Bisphenols and triclosan are considered as potential thyroid disruptors. While mild alterations in maternal thyroid function can result in adverse pregnancy and child developmental outcomes, there is still uncertainty whether bisphenols or triclosan can interfere with thyroid function during pregnancy. Objectives: We aimed to investigate the association of urinary bisphenol A (BPA), bisphenol S (BPS), bisphenol F (BPF) and triclosan with early pregnancy thyroid function. Methods: This study was embedded in the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy study (SELMA), a population-based prospective pregnancy cohort. In total, 1996 participants were included in the current study. Maternal urinary concentrations of three bisphenols and triclosan, collected at median (95% range) 10 (6-14) weeks of pregnancy as well as serum concentrations of thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were measured. Results: Higher BPA levels were associated with lower TT4 concentrations (non-monotonic, P=0.03), a lower FT4/FT3 ratio (beta [SE] -0.02 [0.01], P=0.03) and a lower TT4/TT3 ratio (beta [SE] -0.73 [0.27], P=0.008). Higher BPF levels were associated with a higher FT3 (beta [SE] 0.01 [0.007], P=0.04). There were no associations between other bisphenols or triclosan and absolute TSH, (F)T4 or (F)T3 concentrations. The association of BPA with thyroid function differed with gestational age. The negative association of BPA with FT4/FT3 and TT4/TT3 ratios was only apparent in early but not late gestation (P for interaction: 0.003, 0.008, respectively). Conclusion: These human data during pregnancy substantiate experimental findings suggesting that BPA could potentially affect thyroid function and deiodinase activities in early gestation.

  • 195. Di Guardo, Antonio
    et al.
    Gouin, Todd
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Scheringer, Martin
    Environmental fate and exposure models: advances and challenges in 21st century chemical risk assessment2018Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, nr 1, s. 58-71Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Environmental fate and exposure models are a powerful means to integrate information on chemicals, their partitioning and degradation behaviour, the environmental scenario and the emissions in order to compile a picture of chemical distribution and fluxes in the multimedia environment. A 1995 pioneering book, resulting from a series of workshops among model developers and users, reported the main advantages and identified needs for research in the field of multimedia fate models. Considerable efforts were devoted to their improvement in the past 25 years and many aspects were refined; notably the inclusion of nanomaterials among the modelled substances, the development of models at different spatial and temporal scales, the estimation of chemical properties and emission data, the incorporation of additional environmental media and processes, the integration of sensitivity and uncertainty analysis in the simulations. However, some challenging issues remain and require research efforts and attention: the need of methods to estimate partition coefficients for polar and ionizable chemical in the environment, a better description of bioavailability in different environments as well as the requirement of injecting more ecological realism in exposure predictions to account for the diversity of ecosystem structures and functions in risk assessment. Finally, to transfer new scientific developments into the realm of regulatory risk assessment, we propose the formation of expert groups that compare, discuss and recommend model modifications and updates and help develop practical tools for risk assessment. Environmental significance Multimedia environmental fate models are regularly employed in the risk assessment of chemicals. They historically evolved from simple approaches to more refined and integrated modeling tools, often provided as part of a tiered strategy. Much work has been devoted to improving various aspects at the process and environmental description levels, but some issues need further research and model development, such as the capability to properly simulate the behaviour of polar and ionizable chemicals in the environment, the biovailability of chemicals in aquatic and terrestrial environments, and variability in time and space to account for more ecological relevance. At the same time, it is important to avoid paralysis by analysis and develop practical tools for regulatory risk assessment that are fit for purpose. We propose the formation of expert groups to address this task.

  • 196. Diamond, Miriam L.
    et al.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Molander, Sverker
    Scheringer, Martin
    Backhaus, Thomas
    Lohmann, Rainer
    Arvidsson, Rickard
    Bergman, Åke
    Hauschild, Michael
    Holoubek, Ivan
    Persson, Linn
    Suzuki, Noriyuki
    Vighi, Marco
    Zetzsch, Cornelius
    Exploring the planetary boundary for chemical pollution2015Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 78, s. 8-15Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Rockstrom et al. (2009a, 2009b) have warned that humanity must reduce anthropogenic impacts defined by nine planetary boundaries if unacceptable global change is to be avoided. Chemical pollution was identified as one of those boundaries for which continued impacts could erode the resilience of ecosystems and humanity. The central concept of the planetary boundary (or boundaries) for chemical pollution (PBCP or PBCPs) is that the Earth has a finite assimilative capacity for chemical pollution, which includes persistent as well as readily degradable chemicals released at local to regional scales, which in aggregate threaten ecosystem and human viability. The PBCP allows humanity to explicitly address the increasingly global aspects of chemical pollution throughout a chemical's life cycle and the need for a global response of internationally coordinated control measures. We submit that sufficient evidence shows stresses on ecosystem and human health at local to global scales, suggesting that conditions are transgressing the safe operating space delimited by a PBCP. As such, current local to global pollution control measures are insufficient. However, while the PBCP is an important conceptual step forward, at this point single or multiple PBCPs are challenging to operationalize due to the extremely large number of commercial chemicals or mixtures of chemicals that cause myriad adverse effects to innumerable species and ecosystems, and the complex linkages between emissions, environmental concentrations, exposures and adverse effects. As well, the normative nature of a PBCP presents challenges of negotiating pollution limits amongst societal groups with differing viewpoints. Thus, a combination of approaches is recommended as follows: develop indicators of chemical pollution, for both control and response variables, that will aid in quantifying a PBCP(s) and gauging progress towards reducing chemical pollution; develop new technologies and technical and social approaches to mitigate global chemical pollution that emphasize a preventative approach; coordinate pollution control and sustainability efforts; and facilitate implementation of multiple (and potentially decentralized) control efforts involving scientists, civil society, government, non-governmental organizations and international bodies.

  • 197. Dickerson, Aisha S.
    et al.
    Ransome, Yusuf
    Karlsson, Oskar
    Stockholms universitet, Science for Life Laboratory (SciLifeLab). Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Human prenatal exposure to polychlorinated biphenyls (PCBs) and risk behaviors in adolescence2019Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 129, s. 247-255Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polychlorinated biphenyls (PCBs) are chemicals used in a variety of products before they were widely banned due to toxic effects in humans and wildlife. Because of continued persistence and ubiquity of these contaminants, risk of exposure to people living in industrialized countries is still high. Experimental research show that developmental exposure to PCB may alter function of brain pleasure centers and potentially influence disinhibitory behaviors, including tobacco and alcohol use. Yet, the potential effects of developmental PCB exposure on adolescent substance use have not been studied in humans. We used the Child Health and Development Studies (CHDS), a prospective birth cohort study in the Oakland and East Bay areas of California, to investigate associations between prenatal exposure to PCB congeners (66, 74, 99, 118, 138, 153, 170, 180, 187, and 203) and later disinhibitory behaviors in adolescents, specifically alcohol consumption and smoking, in a randomly selected sample (n = 554). Total prenatal PCB exposure was not associated with disinhibitory behaviors, among adolescents. However, the adjusted odds ratio (aOR) for being a current smoker, was higher in subjects within the third quartile of maternal PCB 66 exposure compared to those below the median (aOR = 1.93; 95% CI 1.05, 3.55). The aOR for drinking > 2 alcoholic beverages per week, were also higher for adolescents within the third (aOR = 1.46; 95% CI 0.86, 2.47) and fourth quartile of PCB 66 exposure (aOR = 1.39; 95% CI 0.83, 2.35), but the differences did not reach statistical significance. These results suggest that this specific PCB congener may play a role inducing neurodevelopmental alterations that could potentially increase the risk of becoming a long-term user of tobacco and possibly alcohol. There were no notable differences between magnitude or direction of effect between boys and girls. Future replicate analyses with larger longitudinal samples and animal experimental studies of potential underlying mechanisms are warranted.

  • 198. Dosis, Ioannis
    et al.
    Athanassiadis, Ioannis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karamanlis, Xanthippos
    Polybrominated diphenyl ethers (PBDEs) in mussels from cultures and natural population2016Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 107, nr 1, s. 92-101Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polybrominated diphenyl ether (PBDE) mass fractions were determined in mussel samples collected from 6 locations around Thermaikos Gulf in north Greece. PBDEs were present in all sampling sites and the average total (2,PBDEs) ranged from 17.7 to 323 ng/g l.w., characterising Thermaikos as low polluted, a fact further supported by congener ratios and literature comparison. Distribution was even among stations with one exception. Congener profiles exhibited predominance of penta-/octa-BDEs as well as BDE-209. Statistical analysis showed significant difference in pollution levels between the two types of mussel cultures. No variations were observed for mussel bunch position or between cultures and natural population. Congener correlation analysis suggested different pollution sources between higher and lower brominated congeners as well as different metabolic/degradation processes. Bioaccumulation factors indicated that an increase in congener bromination degree leads to bioaccumulation capacity reduction. Consumption of mussels from Thermaikos gulf area poses no threat for public health concerning PBDEs.

  • 199. Downing, Simone
    et al.
    Scott, Laura Louise
    Zguna, Nadezda
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Downing, Timothy Grant
    Human Scalp Hair as an Indicator of Exposure to the Environmental Toxin -N-Methylamino-l-alanine2018Ingår i: Toxins, ISSN 2072-6651, E-ISSN 2072-6651, Vol. 10, nr 1, artikel-id 14Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Dietary or aerosol exposure to the environmental neurotoxin -N-methylamino-l-alanine (BMAA) is a putative risk factor for the development of sporadic neurodegenerative disease. There are many potential sources of BMAA in the environment, but BMAA presence and quantities are highly variable. It has been suggested that BMAA in human hair may serve as an indicator of exposure. We sought to evaluate the use of the BMAA content of human scalp hair as an indicator of exposure, as well as the correlation between specific lifestyle or dietary habits, reported as hypothesised exposure risk factors, and BMAA in hair. Scalp hair samples and questionnaires were collected from participants in a small residential village surrounding a freshwater impoundment renowned for toxic cyanobacterial blooms. Data suggested a positive correlation between hair BMAA content and consumption of shellfish, and possibly pork. No statistically significant correlations were observed between hair BMAA content and residential proximity to the water or any other variable. Hair BMAA content was highly variable, and in terms of exposure, probably reflects primarily dietary exposure. However, the BMAA content of human hair may be affected to a great extent by several other factors, and as such, should be used with caution when evaluating human BMAA exposure, or correlating exposure to neurodegenerative disease incidence.

  • 200. Drage, Daniel S.
    et al.
    Newton, Seth
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Harrad, Stuart
    Concentrations of legacy and emerging flame retardants in air and soil on a rural-urban transect in the UK West Midlands2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 148, s. 195-203Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Passive air samples were collected monthly for 6 months from 8 sites along a transect of Birmingham, United Kingdom between June 2012 and January 2013. Soil samples were collected once at each site. Average concentrations of BDE-209, ΣPBDEs17:183 and ΣPBDEs in ambient air were 150, 49, and 180 pg m−3, respectively. Atmospheric concentrations of PBDEs were negatively correlated with distance from the city centre, exhibiting an “urban pulse”. The average ΣHBCDD air concentration was 100 pg m−3, however concentrations were not correlated with distance from the city centre. Several emerging flame retardants (EFRs) were identified in air and/or soil samples: 2,3,4,5-tetrabromo-bis(2-ethylhexyl) phthalate (BEH-TEBP), 1,2-dibromo-4-(1,2 dibromoethyl)cyclohexane (TBECH or DBE-DBCH), allyl 2,4,6-tribromophenyl ether (ATE), 2-bromoallyl 2,4,6-tribromophenyl ether (BATE), decabromodiphenyl ethane (DBDPE), and dechlorane plus (DP or DDC-CO). Average concentrations of BDE-209, ΣPBDEs17:183 and ΣPBDEs in soil were 11, 3.6, and 15 ng g−1 soil organic matter. PBDE concentrations in soil were higher at sites closest to the city centre, however correlations with distance from the city centre were not significant. BDEs-47 and -99 contributed more to ΣPBDEs in soil samples than air samples, but in both, the predominant congener was BDE-209. BATE was more abundant in air than soil but ATE was abundant in soil but not air.

1234567 151 - 200 av 929
RefereraExporteraLänk till träfflistan
Permanent länk
Referera
Referensformat
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Annat format
Fler format
Språk
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Annat språk
Fler språk
Utmatningsformat
  • html
  • text
  • asciidoc
  • rtf