Digitala Vetenskapliga Arkivet

Ändra sökning
Avgränsa sökresultatet
1234567 151 - 200 av 1734
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.
    Beranek, Luke P.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    van Staal, Cees R.
    McClelland, William C.
    Israel, Steve
    Mihalynuk, Mitch G.
    Detrital zircon Hf isotopic compositions indicate a northern Caledonian connection for the Alexander terrane2013Ingår i: Lithosphere, ISSN 1941-8264, E-ISSN 1947-4253, Vol. 5, nr 2, s. 163-168Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Various plate reconstructions predict that the Alexander terrane, a Neoproterozoic-Jurassic crustal fragment now located in the North American Cordillera, evolved in proximity to the northern Appalachian-Caledonian convergent margin during assembly of supercontinent Laurussia. To test stratigraphic connections with Laurussia that are implied by these plate reconstructions, we measured the Hf isotopic compositions of 176 detrital zircons from two relevant sedimentary sequences of the Alexander terrane. An older, Upper Silurian-Lower Devonian terrestrial to shallow-marine molasse sequence yields 405-490 Ma detrital zircons with negative epsilon(Hf(t)) values and Mesoproterozoic to Paleoproterozoic Hf model ages. In combination with paleomagnetic and biogeographic constraints, these Hf data argue for the molasse strata to be now-displaced equivalents of the Old Red Sandstone and primarily sourced from crustally contaminated granitoids in the Greenland, Svalbard, or British Caledonides. Late Silurian-Early Devonian orogenesis in the Alexander terrane is therefore likely related to the Scandian-Salinic phase of Appalachian-Caledonian mountain building. Younger, Middle Devonian sequences of the Alexander terrane are endowed in 390-490 Ma detrital zircons with positive epsilon(Hf(t)) values and Neoproterozoic Hf model ages. These isotopic signatures are consistent with the erosion of local basement rocks during the opening of the Slide Mountain-Angayucham backarc rift and tectonic separation of the Alexander terrane from northern Laurussia.

  • 152.
    Berg, Sylvia E.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper. Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Silicic Magma Genesis in Basalt-dominated Oceanic Settings: Examples from Iceland and the Canary Islands2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The origin of silicic magma in basalt-dominated oceanic settings is fundamental to our understanding of magmatic processes and formation of the earliest continental crust. Particularly significant is magma-crust interaction that can modify the composition of magma and the dynamics of volcanism. This thesis investigates silicic magma genesis on different scales in two ocean island settings. First, volcanic products from a series of voluminous Neogene silicic centres in northeast Iceland are investigated using rock and mineral geochemistry, U-Pb geochronology, and oxygen isotope analysis. Second, interfacial processes of magma-crust interaction are investigated using geochemistry and 3D X-ray computed microtomography on crustal xenoliths from the 2011-12 El Hierro eruption, Canary Islands.

    The results from northeast Iceland constrain a rapid outburst of silicic magmatism driven by a flare of the Iceland plume and/or by formation of a new rift zone, causing large volume injection of basaltic magma into hydrated basaltic crust. This promoted crustal recycling by partial melting of the hydrothermally altered Icelandic crust, thereby producing mixed-origin silicic melt pockets that reflect the heterogeneous nature of the crustal protolith with respect to oxygen isotopes. In particular, a previously unrecognised high-δ18O end-member on Iceland was documented, which implies potentially complex multi-component assimilation histories for magmas ascending through the Icelandic crust. Common geochemical traits between Icelandic and Hadean zircon populations strengthen the concept of Iceland as an analogue for early Earth, implying that crustal recycling in emergent rifts was pivotal in generating Earth’s earliest continental silicic crust.

    Crustal xenoliths from the El Hierro 2011-2012 eruption underline the role of partial melting and assimilation of pre-island sedimentary layers in the early shield-building phase of ocean islands. This phenomenon may contribute to the formation of evolved magmas, and importantly, the release of volatiles from the xenoliths may be sufficient to increase the volatile load of the magma and temporarily alter the character and intensity of an eruption.

    This thesis sheds new light on the generation of silicic magma in basalt-dominated oceanic settings and emphasises the relevance of magma-crust interaction for magma evolution, silicic crust formation, and eruption style from early Earth to present.

    Ladda ner fulltext (pdf)
    fulltext
    Ladda ner (jpg)
    presentationsbild
  • 153.
    Berg, Sylvia E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Burchardt, Steffi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Deegan, Frances
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town.
    Whitehouse, Martin
    Department of Geosciences, Swedish Museum of Natural History.
    Krumbholz, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Gústafsson, Ludvik
    Samband Islenskra Sveitarfélag.
    Rapid generation of high-silica magmas in basalt-dominated rift settingsManuskript (preprint) (Övrigt vetenskapligt)
  • 154.
    Berg, Sylvia E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Deegan, Frances
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Burchardt, Steffi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Ellis, Ben
    Inst. f. Geochemie und Petrologie, ETH.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Meade, Fiona
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Zircons from northeast Iceland analogous to those from early EarthManuskript (preprint) (Övrigt vetenskapligt)
  • 155.
    Berg, Sylvia E.
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town.
    Riishuus, Morten
    Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland.
    Deegan, Frances
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Burchardt, Steffi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Origin of high whole-rock δ18O values in rhyolites from northeast IcelandManuskript (preprint) (Övrigt vetenskapligt)
  • 156.
    Berg, Sylvia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Burchardt, Steffi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Deegan, Frances
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Riishuus, Morten S.
    Nordic Volcanological Center. Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavik.
    Whitehouse, Martin J.
    Dept. of Geosciences, Swedish Museum of Natural History, SE-104 05, Stockholm, Sweden.
    Harris, Chris
    Dept. of Geological Sciences, University of Cape Town, Rondebosch, South Africa,.
    Freda, Carmela
    Istituto Nazionale di Geofisica e Vulcanologia (INGV), Rome, Italy.
    Ellis, Ben S.
    Inst. f. Geochemie und Petrologie, ETH, Clausiusstrasse 25, 8092, Zurich, Switzerland.
    Krumbholz, Michael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Mineralogi, petrologi och tektonik.
    Gústafsson, Ludvik E.
    Samband Islenskra Sveitarfélag, Borgartúni 30, pósthólf 8100, 128 Reykjavik, Iceland.
    Rapid high-silica magma generation in basalt-dominated rift settings2015Konferensbidrag (Övrigt vetenskapligt)
  • 157.
    Berg, Sylvia
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Riishuus, M.S.
    Burchardt, Steffi
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Deegan, Frances
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Harris, C.
    Voluminous outburst of silicic low d18O magma in NE-Iceland inferred from zircon d18O and U-Pb geochronology2013Konferensbidrag (Övrigt vetenskapligt)
  • 158.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Gustafsson, Jon Petter
    Kungliga Tekniska Högskolan, Skolan för arkitektur och samhällsbyggnad (ABE), Institutionen för hållbar utveckling, miljövetenskap och teknik (SEED).
    Åström, Mats E.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Aluminium speciation in boreal catchments enriched in fluoride2012Konferensbidrag (Övrigt vetenskapligt)
  • 159.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Mathurin, Frédéric A.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Drake, Henrik
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Åström, Mats E.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Fluoride in groundwater of regolith and bedrock (0-900 meters depth) in a granitoidic setting, SE Sweden2013Ingår i: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 77, nr 5, s. 691-691Artikel i tidskrift (Övrigt vetenskapligt)
  • 160.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Mathurin, Frédéric A.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Drake, Henrik
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Åström, Mats E.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Geological, mineralogical and hydrological controls of fluoride in fresh groundwater in Quaternary deposits and bedrock fractures in a coastal area with Proterozoic granitoidsManuskript (preprint) (Övrigt vetenskapligt)
  • 161.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Peltola, Pasi
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Drake, Henrik
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Åström, Mats E.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Fluoride patterns in a boreal stream influenced by bedrock and hydrology2011Ingår i: Goldschmidt Conference Abstracts 2011. Mineralogical Magazine, Vol. 75 (3), 2011, s. 517-517Konferensbidrag (Refereegranskat)
  • 162.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Peltola, Pasi
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Drake, Henrik
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Åström, Mats E.
    Linnéuniversitetet, Fakultetsnämnden för naturvetenskap och teknik, Institutionen för naturvetenskap, NV.
    Impact of a Fluorine-Rich Granite Intrusion on Levels and Distribution of Fluoride in a Small Boreal Catchment2012Ingår i: Aquatic geochemistry, ISSN 1380-6165, E-ISSN 1573-1421, Vol. 18, nr 2, s. 77-94Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper explores the influence of a fluorine-rich granite on fluoride concentration in a small boreal catchment in northern Europe. The materials include stream water and shallow groundwater sampled in spatial and temporal dimensions, and analytical data on fluoride and a number of ancillary variables. Fluoride increased strongly towards the lower reaches of the catchment—at the stream outlet the concentrations were up to 4.2 mg L −1 and 1.6–4.7 times higher than upstream. Additionally, fluoride concentrations were particularly high in groundwater and small surface-water bodies (including quarries) above or in direct contact with the granite and showed a strong inverse correlation with water discharge in the stream. Taken together, these data and patterns pin-point the granite intrusion as the ultimate source, explaining the abundance and distribution of dissolved fluoride within the catchment. The granite most likely deliver fluoride to the stream by three mechanisms: (1) weathering of the fine fraction of glacial deposits, derived from the granite and associated fluorine-rich greisen alterations, (2) large relative input of baseflow, partially originating in the granite and greisen, into the lower reaches during low flow in particular, and (3) water-conducting fractures or fracture zones running through the fluorine-rich granite and greisen.

  • 163.
    Berger, Tobias
    et al.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Yu, Changxun
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Drake, Henrik
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Peltola, Pasi
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Svensson, Daniel
    Åström, Mats E.
    Linnéuniversitetet, Fakulteten för Hälso- och livsvetenskap (FHL), Institutionen för biologi och miljö (BOM).
    Fluorine geochemistry of Quaternary deposits in a nemo-boreal catchment with elevated dissolved fluoride in surface waters and groundwaterManuskript (preprint) (Övrigt vetenskapligt)
  • 164.
    Berggren Kleja, Dan
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Elert, Mark
    Kemakta Konsult AB.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Jarvis, las
    Markvetenskap, SLU.
    Norrström, Ann-Catrine
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Metallers mobilitet i mark2006Rapport (Refereegranskat)
    Abstract [sv]

    I rapporten beskrivs nuvarande kunskapsläge när det gäller metallers uppträdande imark. Riskbedömningar för metaller i förorenad mark diskuteras.De flesta metaller binds i viss utsträckning i marken, oftast genom olika ytreaktioner med markens organiska material eller med järn- och aluminiumoxider, ochibland även genom utfällningsreaktioner. I vilken omfattning detta sker beror avfaktorer som t.ex. pH, redoxförhållanden, löst organiskt material (DOC) i markvattnet, samt förekomst av konkurrerande joner. Det är också viktigt att beaktavilka former metallerna förekommer som i markvattnet. Komplexbildning medt.ex. DOC minskar i regel toxiciteten. För att bättre ta hänsyn till markkemiskaförhållanden i riskbedömningen bör geokemiska modeller komma till ökad användning.Metaller lösta i vattnet följer med när vattnet strömmar och kan transporterastill grund- och ytvatten eller tas upp av växter. Hur snabbt detta går beror, förutomkemiska och biologiska processer, även på en rad olika jordegenskaper. Till exempel innehåller vissa jordar s.k. makroporer vilka ger upphov till preferentiellt flöde.Detta innebär att en del av metallerna snabbare kan transporteras genom marken,förbi jordpartiklar där metallerna annars skulle bindas.De olika modeller som används för att beskriva påverkan av markförorening pågrundvatten kan delas in i två grupper: stationära modeller antar att källtermen ärkonstant och tar enbart hänsyn till den utspädning som sker i grundvattnet. Exempel på sådana modeller är den svenska riktvärdesmodellen, JAGG och RBCA. I detvå senare modellerna finns möjlighet att ta hänsyn till nedbrytning av organiskaämnen. Tidsberoende modeller antar en avklingande källterm och en tidsberoendetransport i grundvattnet, exempelvis RISC och TAC-modellen. För beräkning avtransport i grundvattnet tas hänsyn till flödes- och fastläggningsmekanismer somadvektion, dispersion och linjär sorption.Med hjälp av laktester kan man uppskatta den andel av metallföroreningen somär löslig i vatten. Denna information kan sedan användas för att beräkna adsorptionsparametrar (Kd-värden, m.m.) för spridningsmodeller. Laktester kan ibland gemissvisande resultat eftersom de orsakar utspädning av provet, bl.a. blir DOCkoncentrationerna alltför låga. Dessutom bör de inte användas för sulfidjordar.Geokemiska modeller kan användas för att förbättra tolkningen av laktester för attfå till stånd realistiska uppskattningar av Kd-värden.Det finns ett antal spridningsmodeller som kan användas för att bedöma riskenför spridning till grundvatten och ytvatten. De är kraftfulla verktyg som dock ännuinte använts i någon större utsträckning i Sverige. Detta beror på flera orsaker, bl.a.de hydrogeologiska förhållandena i Sverige, behovet av anpassningen av de modeller som är allmänt tillgängliga, svårigheter att ta fram bra dataunderlag samt ensvag tradition i att använda modeller och förstå modellresultat.Ett par angelägna forsknings- och utvecklingsinsatser är att ta fram bättre uppskattningar av metalladsorption i svensk mark, och att anpassa existerande spridningsmodeller för användning i riskbedömningar.

  • 165.
    Berglund, S.
    et al.
    Luleå tekniska universitet.
    Ekström, T.K,
    Geological Survey of Sweden.
    Arsenopyrite and sphalerite as T-P indicators in sulfide ores from northern Sweden1980Ingår i: Mineralium Deposita, ISSN 0026-4598, E-ISSN 1432-1866, Vol. 15, nr 2, s. 175-187Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The compositions of arsenopyrite and sphalerite from five Swedish metamorphosed Cu, Zn-sulfide deposits are related to T and P, according to the methods described by Kretschmar and Scott (1976) and Scott (1973). The As/S ratio of arsenopyrite indicates an equilibrium temperature around 400°C for all the deposits studied, whereas the sphalerite barometer shows pressures between 5 and 7 kb. The mineral assemblages of the bedrocks indicate a similar temperature but a lower pressure. A constant fs2 is probably only effective over distances of millimetres or a few centimetres in the samples studied. The fs2 has always been lower in the surrounding rocks than in the ores as indicated by a higher As/S in arsenopyrite, more FeS in sphalerites and the absence of pyrite.

  • 166. Bergqvist, Claes
    et al.
    Herbert, Roger
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Luft-, vatten- och landskapslära.
    Persson, Ingmar
    Greger, Maria
    Plants influence on arsenic availability and speciation in therhizosphere, roots and shoots of three different vegetables2014Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 184, s. 540-546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The toxicity of arsenic (As) in the environment is controlled by its concentration, availability andspeciation. The aims of the study were to evaluate the accumulation and speciation of As in carrot,lettuce and spinach cultivated in soils with various As concentrations and to estimate the concomitanthealth risks associated with the consumption of the vegetables. Arsenic concentration and speciation inplant tissues and soils was analysed by HPLC, AAS and XANES spectroscopy. To estimate the plants influencein the rhizosphere, organic acids in lettuce root exudates were analysed by ion chromatography.The results showed that the As accumulation was higher in plants cultivated in soil with higher Asextractability. Arsenate predominated in the soils, rhizosphere and root exudates of lettuce. Succinic acidwas the major organic acid in lettuce root exudates. Ingestion of the tested vegetables may result in anintake of elevated levels of inorganic As.

  • 167.
    Bertrand, G.
    et al.
    Instituto de Geociências, CEPAS (Groundwater Research Center), University of São Paulo.
    Siergieiev, Dmytro
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Ala-Aho, P.
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Rossi, P.M.
    Water Resources and Environmental Engineering Laboratory, Department of Process and Environmental Engineering, University of Oulu.
    Environmental tracers and indicators bringing together groundwater, surface water and groundwater-dependent ecosystems: importance of scale in choosing relevant tools2014Ingår i: Environmental Earth Sciences, ISSN 1866-6280, E-ISSN 1866-6299, Vol. 72, nr 3, s. 813-827Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Groundwater-surface water (GW-SW) interactions cover a broad range of hydrogeological and biological processes and are controlled by natural and anthropogenic factors at various spatio-temporal scales, from watershed to hyporheic/hypolentic zone. Understanding these processes is vital in the protection of groundwater-dependent ecosystems (GDEs) increasingly required in water resources legislation across the world. The use of environmental tracers and indicators that are relevant simultaneously for groundwater, surface water and biocenoses-biotope interactions constitutes a powerful tool to succeed in the management task. However, tracer type must be chosen according to the scale of interest and tracer use thus requires a good conceptual understanding of the processes to be evaluated. This paper reviews various GW-SW interaction processes and their drivers and, based on available knowledge, systemises application of conservative tracers and semi-conservative and reactive environmental indicators at different spatial scales. Biocenoses-biotopes relationships are viewed as a possible transition tool between scales. Relation between principal application of the environmental tracers and indicators, examples and guidelines are further proposed for examining GW-SW interactions from a hydrogeological and biological point of view by demonstrating the usability of the tracers/indicators and providing recommendations for the scientific community and decision makers.

  • 168.
    Biagion, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of turneaureite, Ca5(AsO4)3Cl, the arsenate analog of chlorapatite and its relationships with the arsenate apatites johnbaumite and svabite2017Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 102, s. 1981-1986Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystal structure of turneaureite, ideally Ca5(AsO4)3Cl, was studied using a specimen from the Brattfors mine, Nordmark, Värmland, Sweden, by means of single-crystal X-ray diffraction data. The structure was refinedto R1 = 0.017 on the basis of 716 unique reflectios with Fo > 4σ(Fo) in the P63/m space group, with unit-cell parameters a = 9.9218(3), c = 6.8638(2) Å, V = 585.16(4) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%; average of 10 spot analyses): SO3 0.22, P2O5 0.20, V2O5 0.01, As2O5 51.76, SiO2 0.06, CaO 41.39, MnO 1.89, SrO 0.12, BaO 0.52, PbO 0.10, Na2O 0.02, F 0.32, Cl 2.56, H2Ocalc 0.58, O(≡F+Cl) –0.71, total 99.04. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.82Mn0.17Ba0.02Sr0.01)∑5.02 (As2.94P0.02S0.02Si0.01)∑2.99O12[Cl0.47(OH)0.42F0.11]∑1.00.Turneaureite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. Owing to its particular chemical composition, the studied turneaureite can be considered as a ternary calcium arsenate apatite; consequently it has several partially filledanion sites within the anion columns. Polarized single-crystal FTIR spectra of the studied sample indicate stronger hydrogen bonding and less diverse short-range atom arrangements around (OH) groups in turneaureite as compared to the related minerals johnbaumite and svabite. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 169.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bindi, Luca
    Università di Firenze, Italy.
    Mauro, Daniela
    Università di Pisa.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Crystal chemistry of sulfates from the Apuan Alps (Tuscany, Italy). V. Scordariite, K8(Fe3+0.67ο0.33)[Fe3+3O(SO4)6(H2O)3)]2(H2O)11 , a new metavoltine-related mineral2019Ingår i: Minerals, ISSN 2075-163X, E-ISSN 2075-163X, Vol. 9, nr 11, s. 1-14, artikel-id 0702Artikel i tidskrift (Refereegranskat)
    Ladda ner fulltext (pdf)
    fulltext
  • 170.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of svabite, Ca5(AsO4)3F, an arsenate member of the apatite supergroup2016Ingår i: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 101, s. 1750-1755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystal structure of svabite, ideally Ca5(AsO4)3F, was studied using a specimen from the Jakobsberg mine, Värmland, Sweden, by means of single-crystal X‑ray diffraction data. The structure was refined to R1 = 0.032 on the basis of 928 unique reflections with Fo > 4s(Fo) in the P63/m space group, with unit-cell parameters a = 9.7268(5), c = 6.9820(4) Å, V = 572.07(5) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%, average of 10 spot analyses): SO3 0.49, P2O5 0.21, V2O5 0.04, As2O5 51.21, SiO2 0.19, CaO 39.31, MnO 0.48, SrO 0.03, PbO 5.19, Na2O 0.13, F 2.12, Cl 0.08, H2Ocalc 0.33, O (≡ F+Cl) –0.91, total 98.90. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.66Pb0.16Mn0.04Na0.03)Σ4.89(As2.96S0.04Si0.02P0.02)Σ3.04O12[F0.74(OH)0.24Cl0.01]. Svabite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. The crystal structure of synthetic Ca5(AsO4)3F was previously reported as triclinic. On the contrary, the present refinement of the crystal structure of svabite shows no deviations from the hexagonal symmetry. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 171.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuove specie mineralogiche Italiane2019Ingår i: Rivista Mineralogica Italiana, Vol. 43, nr 4, s. 256-262Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Ladda ner fulltext (pdf)
    fulltext
  • 172.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuovi minerali Italiana - La approvazioni 20172018Ingår i: Revista Mineralogica Italiana, ISSN 0391-9641, Vol. 42, nr 3, s. 190-197Artikel i tidskrift (Övrig (populärvetenskap, debatt, mm))
    Ladda ner fulltext (pdf)
    fulltext
  • 173.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pasero, Marco
    Università di Pisa, Italy..
    Karlsson, Andreas
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hydroxylhedyphane, Ca2Pb3(AsO4)3(OH), a new member of the apatite supergroup from Långban, Sweden2019Ingår i: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 31, nr 5-6, s. 1007-1014Artikel i tidskrift (Refereegranskat)
  • 174.
    Bidleman, Terry
    et al.
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Andersson, Agneta
    Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden, Umeå Marine Sciences Centre, Hörnefors, Sweden.
    Jantunen, Liisa
    Centre for Atmospheric Research Experiments, Environment and Climate Change Canada, Canada.
    Kucklick, John
    Chemical Sciences Division, National Institute of Standards and Technology, Hollings Marine Laboratory, Charleston, SC, USA.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten. Research Unit: Environmental Sciences and Management, North–West University, Potchefstroom, South Africa.
    Letcher, Robert
    Ecotoxicology and Wildlife Health Division, Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Ottawa, Canada.
    Tysklind, Mats
    Department of Chemistry, Umeå University, Umeå, Sweden.
    Wong, Fiona
    Air Quality Processes Research Section, Environment and Climate Change Canada, Toronto, Canada.
    A review of halogenated natural products in Arctic, Subarctic and Nordic ecosystems2019Ingår i: Emerging Contaminants, ISSN 2405-6650, E-ISSN 2405-6642, Vol. 5, s. 89-115Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Halogenated natural products (HNPs) are organic compounds containing bromine, chlorine, iodine, andrarely fluorine. HNPs comprise many classes of compounds, ranging in complexity from halocarbons tohigher molecular weight compounds, which often contain oxygen and/or nitrogen atoms in addition tohalogens. Many HNPs are biosynthesized by marine bacteria, macroalgae, phytoplankton, tunicates,corals, worms, sponges and other invertebrates. This paper reviews HNPs in Arctic, Subarctic and Nordicecosystems and is based on sections of Chapter 2.16 in the Arctic Monitoring and Assessment Program(AMAP) assessment Chemicals of Emerging Arctic Concern (AMAP, 2017) which deal with the highermolecular weight HNPs. Material is updated and expanded to include more Nordic examples. Much ofthe chapter is devoted to “bromophenolic” HNPs, viz bromophenols (BPs) and transformation productsbromoanisoles (BAs), hydroxylated and methoxylated bromodiphenyl ethers (OH-BDEs, MeO-BDEs) andpolybrominated dibenzo-p-dioxins (PBDDs), since these HNPs are most frequently reported. Othersdiscussed are 2,20-dimethoxy-3,30,5,50-tetrabromobiphenyl (2,20-dimethoxy-BB80), polyhalogenated 10-methyl-1,20-bipyrroles (PMBPs), polyhalogenated 1,10-dimethyl-2,20-bipyrroles (PDBPs), polyhalogenatedN-methylpyrroles (PMPs), polyhalogenated N-methylindoles (PMIs), bromoheptyl- and bromooctylpyrroles, (1R,2S,4R,5R,10E)-2-bromo-1-bromomethyl-1,4-dichloro-5-(20-chloroethenyl)-5-methylcyclohexane (mixed halogenated compound MHC-1), polybrominated hexahydroxanthene derivatives(PBHDs) and polyhalogenated carbazoles (PHCs). Aspects of HNPs covered are physicochemicalproperties, sources and production, transformation processes, concentrations and trends in the physicalenvironment and biota (marine and freshwater). Toxic properties of some HNPs and a discussion of howclimate change might affect HNPs production and distribution are also included. The review concludeswith a summary of research needs to better understand the role of HNPs as “chemicals of emergingArctic concern”.

    Ladda ner fulltext (pdf)
    fulltext
  • 175.
    Bidleman, Terry
    et al.
    Umeå University, Sweden.
    Kurt-Karakus, Perihan
    Bahcesehir University, Istanbul, Turkey.
    Armitage, James
    University of Toronto, Ontario, Canada.
    Brown, Tanya
    University of Victoria, British Columbia, Canada.
    Danon Schaffer, Monica
    University of British Columbia, Vancouver, Canada.
    Helm, Paul
    Ontario Ministry of the Environment, Toronto, Canada.
    Hung, Haley
    Meteorological Services Canada .
    Jantunen, Liisa
    Environment Canada.
    Kylin, Henrik
    Linköpings universitet, Institutionen för tema, Tema Miljöförändring. Linköpings universitet, Filosofiska fakulteten.
    Li, Yi-Fan
    Environment, Canada.
    Loock, Daniela
    Royal Military College of Canada.
    Luttmer, Carol
    Royal Military College of Canada.
    Ma, Jianmin
    Lanzhou University, Peoples Republic of China.
    Macdonald, Robie
    Fisheries and Oceans, Canada.
    Mackay, Don
    Trent University, Peterborough, Ontario, Canada.
    Reid, Liisa
    Trent University, Peterborough, Ontario, Canada.
    Reimer, Ken
    Royal Military College of Canada.
    Chapter 2: Properties, sources, global fate and transport2013Ingår i: Canadian Arctic Contaminants Assessment Report III 2013: Persistent Organic Pollutants in Canada’ s North / [ed] Derek Muir, Perihan Kurt-Karakus and Peter Stow, Ottawa: Northern Contaminants Program, Aboriginal Affairs and Northern Development Canada , 2013, s. 19-146Kapitel i bok, del av antologi (Refereegranskat)
    Abstract [en]

    Part II of the second Canadian Arctic Contaminants Assessment Report (CACAR-II) began with a section on “Physicochemical Properties of Persistent Organic Pollutants”, which identified key physicochemical (pchem) properties, provided the rationale for their measurement or prediction and tabulated literature citations for chemicals that are of concern to the NCP (Bidleman et al. 2003). The section also discussed temperature dependence of pchem properties and their applications to describing partitioning in the physical environment.

    There is, and will continue to be, emphasis on predictive approaches to screening chemicals for persistence, bioaccumulation and toxic (PB&T)properties, as well as long-range atmospheric transport (LRAT) potential (Brown and Wania 2008, Czub et al. 2008, Fenner et al. 2005, Gouin andWania 2007, Howard and Muir 2010, Klasmeier et al. 2006, Matthies et al. 2009, Muir and Howard 2006). This has created the need for determining pchem properties of new and emerging chemicals of concern.

    Predicting gas exchange cycles of legacy persistent organic pollutants (POPs) and new and emerging chemicals of concern places a high demand on the accuracy of pchem properties, particularly the air/water partition coefficient, KAW. Hexachlorocyclohexanes (HCHs) in Arctic Ocean surface waters are close to air-water equilibrium, with excursions toward net volatilization or deposition that vary with location and season (Hargrave et al. 1993, Jantunen et al. 2008a, Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) while hexachlorobenzene (HCB) (Lohmann et al. 2009, Su et al. 2006, Wong et al. 2011) and some current use pesticides (CUPs) (Wong et al. 2011) are undergoing net deposition. The predicted Arctic Contamination Potential (ACP) for persistent organic chemicals is strongly influenced by ice cover due to its effect on air-water gas exchange (Meyer and Wania 2007).

    Many advances have taken place and numerous papers have been published since CACAR-II, which present new measurements and predictions of pchem properties. This section does not attempt to provide a comprehensive review of the field, or to compile pchem properties from the many studies. The approach taken is to highlight the reports which are most relevant to polar science, particularly in areas of improving reliability of pchem properties for POPs, improving experimental techniques and comparing predictive methods. The section ends with a discussion of polyparameter linear free energy relationships (pp-LFERs), which goes beyond partitioning descriptions based on single pchem properties by taking into account specific chemical interactions that can take place in airsurface and water-surface exchange processes. A detailed list of chemical names and nomenclature are provided in the Glossary.

    Ladda ner fulltext (pdf)
    fulltext
    Ladda ner (jpg)
    presentationsbild
  • 176.
    Billström, Kjell
    et al.
    Swedish Museum of Natural History.
    Frietsch, Rudyard
    Luleå tekniska universitet.
    Perdahl, Jan-Anders
    Luleå tekniska universitet.
    Regional variations in the Pb isotopic compositions of ore galena across the Archaean-Proterozoic border in northern Sweden1997Ingår i: Precambrian Research, ISSN 0301-9268, E-ISSN 1872-7433, Vol. 81, nr 1-2, s. 83-99Artikel i tidskrift (Refereegranskat)
  • 177. Billström, Kjell
    et al.
    Åberg, G.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Isotopic and geochemical data of the Pingstaberg Mo-bearing granite in Bergslagen, south central Sweden1988Ingår i: Geologie & Mijnbouw, ISSN 0016-7746, E-ISSN 1573-9708, Vol. 67, nr 2-4, s. 255-263Artikel i tidskrift (Refereegranskat)
  • 178. Billström, Kjell
    et al.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    On the origin of the Yxsjöberg Cu-W skarn deposit, central Sweden: isotopic evidence1989Ingår i: Precambrian granitoids: petrogenesis, geochemistry and metallogeny : symposium : August 14-17, 1989, University of Helsinki, Finland. Abstracts / [ed] Ilmari Haapala; Yrjö Kähkönen, Espoo: Geological Survey of Finland , 1989, s. 14-Konferensbidrag (Övrigt vetenskapligt)
  • 179.
    Billström, Kjell
    et al.
    Laboratory for Isotope Geology. Swedish Museum of Natural History, Stockholm.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    U-Pb zircon age of the Rostberget W-occurrence, northern Sweden1989Ingår i: Geologiska föreningens i Stockholm förhandlingar, ISSN 0016-786X, Vol. 111, nr 2, s. 121-126Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Anomalously U-rich granites of the so-called Revsund type, associated with W- and Sn-enrichments, occur in the Gunnarn area close to Storuman in northern Sweden. At Rostberget, a swarm of thin undeformed wolframite-bearing greisen veins are situated in the interior of the Joran granite intrusion. We have dated zircons from a sample of the greisen veins with the U-Pb method. The veins are less than 1 cm wide and it is likely that the sample also contains zircons from the immediately surrounding altered granite. The mineralizing event and connected metasomatic processes probably released Zr from the granite which became available for zircon growth processes in the greisen veins. One notable feature, probably due to the greisen-forming processes, is the very high common Pb concentrations characterizing the zircons. By varying the assumed common Pb composition in the calculations, the effect on resulting intercept ages has been evaluated. The obtained age interval (1775-1782 Ma) is typical of formation ages for Revsund granites, which indicates that the mineralization event at Rostberget followed closely upon the granite emplacement. We conclude that the Revsund-type granites, which cover large areas, were generated in a narrow time interval 1790-1775 Ma ago.

  • 180. Birkholz, Axel
    et al.
    Smittenberg, Rienk H.
    Geological Institute, ETH Zürich, Schweiz.
    Bernasconi, Stefano
    Hajdas, Irka
    Wacker, Lukas
    Isolation and compound specific radiocarbon dating of terrigenous branched glycerol dialkyl glycerol tetraethers (brGDGTs)2013Ingår i: Organic Geochemistry, ISSN 0146-6380, E-ISSN 1873-5290, Vol. 60, s. 9-19Artikel i tidskrift (Refereegranskat)
  • 181.
    Biswas, Ashis
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Neidhardt, H.
    Karlsruhe Institute of Technology, Germany.
    Halder, Dipti
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Kundu, A.K.
    University of Kalyani, India.
    Chatterjee, Debashis
    University of Kalyani, India.
    Berner, Z.
    Karlsruhe Institute of Technology, Germany.
    Bhattacharya, Prosun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik.
    Surface complexation modeling of temporal variability of arsenic in groundwater: Estimating the role of competing ions in the mobilization processes2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study investigates the relative roles of different competing ions on the mobilization of arsenic (As) by surface complexation modeling of As rich groundwater in the aquifer of Bengal Basin. Two sets of piezometers, installed at different depths of the shallow aquifer (<50 m), have been monitored for As and other relevant hydrogeochemical parameters over a period of 20 months. The potentiality of two different surface complexation models (SCM), developed for ferrihydrite and goethite has been explored to account for the observed temporal variation in As(III) and As(V) concentration in groundwater. The SCM for ferrihydrite appears as the better predictor for the observed variation in both As(III) and As(V) concentration. It is estimated that among the competing ions PO43- is the major competitor of As(III) and As(V) adsorption into Fe oxyhydroxide and competing ability of the ions decreases as PO43- >> Fe(II) > H4SiO4 = HCO3-. The result of sensitivity test indicates that the competition of PO43- with As for the adsorption sites might already reach nearly to the stage of maxima. It is also shown that a slight increase or decrease in pH can have overwhelming effect on the mobility of As(III) and As(V) by changing their concentration oppositely. It appears that only the reductive dissolution of Fe oxyhydroxide cannot explain the observed high As concentration in the groundwater of Bengal Basin. In absence of potential competition for the adsorption sites, As released due to reductive dissolution of Fe oxyhydroxide would have been re-adsorbed into the residual Fe phases. This study suggests that the reductive dissolution of Fe oxyhydroxide followed by competitive ion exchange with the aquifer sediment is the processes conducive for As enrichment in groundwater of the sedimentary aquifers.

  • 182.
    Biswas, Ashis
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. University of Kalyani.
    Gustafsson, Jon Petter
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. Swedish University of Agricultural Sciences.
    Neidhardt, Harald
    Karlsruhe Institute of Technology, Germany.
    Halder, Dipti
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik, Mark- och vattenteknik. University of Kalyani.
    Kundu, Amit Kumar
    University of Kalyani, India.
    Chatterjee, Debashis
    University of Kalyani, India.
    Berner, Zsolt
    Karlsruhe Institute of Technology, Germany.
    Bhattacharya, Prosun
    University of Kalyani.
    Estimating the role of competing ions on the arsenic mobilization processes in the aquifers of Bengal Basin by surface complexation modeling2013Konferensbidrag (Refereegranskat)
    Abstract [en]

    This study investigates the relative roles of the different competing ions on the arsenic (As) mobilization in the sedimentary aquifers of Bengal basin by surface complexation modeling of the temporal varaibility of As in shallow (<50 m) groundwater. Two sets of piezometers (2×5 = 10), installed at the two sites with relatively contrasting dissolved As concentration in groundwater, were monitored bi-weekly for As and other hydrogeochemical parameters over a period of 20 months. The estimation of the standard deviation (SD) for As(III) reflects strong temporal variation (SD ≥10 μg/L) in all the piezometers of two sites over the monitoring period. Particularly, the variation is more prominent in the shallowest part of the aquifer, where the site specific cyclic trends are evident. While, As(V) shows significant temporal variation in the piezometers of high As site only and no specific trend is reflected in the variation.

    Two different surface complexation models (SCMs), developed for ferrihydrite and goethite have been explored to account for the observed temporal variation in As(III) and As(V) concentrations. The SCM for ferrihydrite has provided the better estimation for both As(III) and As(V) variations.

    Among the different competing ions, PO43- appears as the major competitor of As(III) and As(V) adsorption onto ferrihydrite and the competition ability decreases in the order PO43- >> Fe(II) > H4SiO4 = HCO3-. It is further revealed that a small decrease in pH significantly increases the concentration of As(III) and decreases the As(V) concentration and vice versa. The present study suggests that the reductive dissolution of Fe oxyhydroxides alone cannot explain the observed high As concentration in groundwater of the sedimentary aquifers. Perhaps, the reductive dissolution of Fe oxyhydroxides followed by competitive sorption reactions with the aquifer sediment is the processes conducive for As enrichment in the groundwater of Bengal basin.

  • 183.
    Biswas, Ashis
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. University of Kalyani, India .
    Neidhardt, Harald
    Kundu, Amit K.
    Halder, Dipti
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik. University of Kalyani, India .
    Chatterjee, Debashis
    Berner, Zsolt
    Jacks, Gunnar
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Bhattacharya, Prosun
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Hållbar utveckling, miljövetenskap och teknik.
    Spatial, vertical and temporal variation of arsenic in shallow aquifers of the Bengal Basin: Controlling geochemical processes2014Ingår i: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 387, s. 157-169Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A detailed understanding of the geochemical processes that regulate the spatial, temporal and vertical variation of dissolved arsenic (As) in shallow aquifers (<50 m) is a prerequisite for sustainable drinking water management in the Bengal Basin. The present study conducted at Chakdaha Block of the Nadia District, West Bengal, India, combined a high resolution hydrogeochemical monitoring study over 20 months from two sets of piezometers (2 x 5) to the sediment geochemistry at areas with high (average:146 mu g/L, n = 5) and relatively low (average: 53.3 mu g/L, n = 10) dissolved As concentrations in groundwater. The determination of the isotopic composition of delta H-2 and delta O-18 in groundwater of the two sites indicated the recharge of evaporative surface water to the aquifer. The concentrations of major aqueous solutes (Ca2+, Mg2+, Na+, K+, HCO3- and Cl-) and electrical conductivity were considerably higher in wells at the high As site compared to the low As site. Additionally, at the high As site, the major ions, Fe, SO42-, electrical conductivity, delta H-2 and delta O-18 showed markedly greater enrichment in the shallowest part (<24 m) of the aquifer compared to the deeper part, reflecting vertical layering of groundwater composition within the aquifer. The oxidation of pyrites has been attributed to the high rate of mineral dissolution resulting in such greater enrichments in this part of the aquifer. In addition, the anthropogenic input with recharge water possibly increased the concentrations of Cl- in this part of the aquifer. The vertical layering of groundwater was absent in the aquifer at the low As site. The absence of such layering and relatively low major ion concentrations and electrical conductivity could be linked to the enhanced aquifer flushing and decreased water-ediment interactions influenced by local-scale groundwater abstraction. The seasonal variations of As concentrations in groundwater were observed only in the shallowest part of the aquifers (<30 m). Furthermore, the As concentrations in groundwater at the uppermost part of the shallow aquifers (<21 m) increased continuously over the monitoring period at both sites. This study supports the view that the reductive dissolution of Fe oxyhydroxides coupled with competitive PO43- sorption reactions in the aquifer sediment enriches As in groundwater of the Bengal Basin. However, the additional Fe released by the weathering of silicate minerals, especially biotite, or the precipitation of Fe as secondary mineral phases such as siderite, vivianite and acid volatile sulfides may result in the decoupling of As and Fe enrichment in groundwater. The redox zonation within the aquifer possibly regulates the vertical distribution of As in the groundwater.

  • 184.
    Björnbom, Pehr
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik.
    Temperature lapse rates at restricted thermodynamic equilibrium in the Earth system2015Ingår i: Dynamics of atmospheres and oceans (Print), ISSN 0377-0265, E-ISSN 1872-6879, Vol. 69, s. 26-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Equilibrium temperature profiles obtained by maximizing the entropy of a column of fluid with a given height and-volume under the influence of gravity are discussed by using numerical experiments. Calculations are made both for the case of an ideal gas and for a liquid with constant isobaric heat capacity, constant compressibility and constant thermal expansion coefficient representing idealized conditions corresponding to atmosphere and ocean. Calculations confirm the classical equilibrium condition by Gibbs that an isothermal temperature profile gives a maximum in entropy constrained by a constant mass and a constant sum of internal and potential energy. However, it was also found that an isentropic profile gives a maximum in entropy constrained by a constant mass and a constant internal energy of the fluid column. On the basis of this result a hypothesis is suggested that the adiabatic lapse rate represents a restricted or transitory and metastable equilibrium state, which has a maximum in entropy with lower value than the maximum in the state with an isothermal lapse rate. This transitory equilibrium state is maintained by passive forces, preventing or slowing down the transition of the system to the final or ultimate equilibrium state.

  • 185.
    Björnerås, C.
    et al.
    Lund University, Lund, Sweden.
    Weyhenmeyer, Gesa A.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Biologiska sektionen, Institutionen för ekologi och genetik, Limnologi.
    Evans, C. D.
    Environm Ctr Wales, Bangor, Wales.
    Gessner, M. O.
    Leibniz Inst Freshwater Ecol & Inland Fisheries I, Stechlin, Germany; TU Berlin, Berlin, Germany.
    Grossart, H. P.
    Potsdam Univ, Potsdam, Germany.
    Kangur, K.
    Estonian Univ Life Sci, Rannu, Estonia.
    Kokorite, I.
    Univ Latvia, Riga, Latvia.
    Kortelainen, P.
    Finnish Environm Inst, Helsinki, Finland.
    Laudon, H.
    Swedish Univ Agr Sci, Umeå, Sweden.
    Lehtoranta, J.
    Finnish Environm Inst, Helsinki, Finland.
    Lottig, N.
    Univ Wisconsin, Madison, USA.
    Monteith, D. T.
    Lancaster Environm Ctr, Lancaster, England.
    Nõges, P.
    Estonian Univ Life Sci, Tartu, Estonia.
    Nõges, T.
    Estonian Univ Life Sci, Tartu, Estonia.
    Oulehle, F.
    Czech Geol Survey, Prague, Czech Republic.
    Riise, G.
    Norwegian Univ Life Sci NMBU, As, Norway.
    Rusak, J. A.
    Ontario Minist Environm & Climate Change, Dorset, Canada.
    Räike, A.
    Finnish Environm Inst, Helsinki, Finland.
    Sire, J.
    Latvian Environm Geol & Meteorol Ctr, Riga, Latvia.
    Sterling, S.
    Dalhousie Univ, Halifax, Canada.
    Kritzberg, E. S.
    Lund University, Lund, Sweden.
    Widespread Increases in Iron Concentration in European and North American Freshwaters2017Ingår i: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 31, nr 10, s. 1488-1500Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters.

    Ladda ner fulltext (pdf)
    fulltext
  • 186.
    Blecken, Godecke-Tobias
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Rentz, Ralf
    Malmgren, Charlotte
    Luleå tekniska universitet, Institutionen för ekonomi, teknik och samhälle, Industriell Ekonomi.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Viklander, Maria
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Arkitektur och vatten.
    Stormwater impact on urban waterways in a cold climate: variations in sediment metal concentrations due to untreated snowmelt discharge2012Ingår i: Journal of Soils and Sediments, ISSN 1439-0108, E-ISSN 1614-7480, Vol. 12, nr 5, s. 758-773Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Purpose: Stormwater discharges include contaminated sediments that accumulate in the receiving water body. It is thus important to investigate sediment and pollutant processes and pathways from the catchment to, and within, the receiving water. These processes may be influenced by seasonal changes. The objective of this study was to investigate the stormwater impact on receiving waters in the Luleå area, Northern Sweden; seasonal changes in contamination loads in the receiving waters due to snowmelt; and factors influencing the pollutant pathways in the receiving waters. Materials and methods: In front of three storm sewer outlets in Luleå, samples of bottom sediment (surface layer 0-2 cm) were collected from the connecting ditches and the downstream water body in autumn and spring (before and after the snow season 2009/2010). The characteristics of the receiving waters differed in geomorphology and vegetation. The sediment was analyzed for loss-on-ignition (LOI), grain size, and bulk concentrations of SiO 2, Al 2O 3, CaO, Fe 2O 3, MnO, Na 2O, P 2O 5, TiO 2, As, Cd, Co, Cr, Cu, Hg, Ni, Pb, S, V, and Zn. The sediment contamination was compared to concentrations at a reference point in Luleå where the bottom sediment was not affected by stormwater discharges and with Swedish environmental quality guidelines. Pearson's correlation and a principal component analysis were used to further evaluate the results. Results and discussion: Relative to the reference point, elevated trace metal concentrations were detected in sediments at all three sampling stations. At two of the stations, seasonal variations in ditch sediment grain size, LOI, and contaminant concentrations were observed, originating from stormwater sediment. Snowmelt runoff caused an increased proportion of fine-grained sediment fractions (<0.063 mm) in spring, mainly due to changes in runoff intensity and high sediment loads in the snowmelt runoff. The retention of metals appeared to be due to low turbulence in the water and the presence of organic material. Conclusions: Stormwater discharge affected the contaminant concentrations in the bottom sediments. The observed seasonal variation of contaminants indicated that relatively high amounts of contaminants are discharged during snowmelt and then reallocated within the receiving water body, either directly or after some temporal retention, depending on the characteristics of the receiving water. A calm water column and the presence of organic material in the receiving water body were crucial for the retention of metals

  • 187.
    Blomberg, Lars G.
    et al.
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Eriksson, Stefan
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Cumnock, Judy A.
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Yamauchi, M.
    Clemmons, J. H.
    Marklund, Göran T.
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Lindqvist, Per-Arne
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Karlsson, Tomas
    KTH, Tidigare Institutioner, Alfvénlaboratoriet. KTH, Skolan för elektro- och systemteknik (EES), Rymd- och plasmafysik.
    Lundin, R.
    Solar windmagnetosphere-ionosphere coupling: an event study based on Freja data2004Ingår i: Journal of Atmospheric and Solar-Terrestrial Physics, ISSN 1364-6826, E-ISSN 1879-1824, Vol. 66, nr 5, s. 375-380Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Freja data are used to study the relative contributions from the high-latitude (reconnection/direct entry) and low-latitude (viscous interaction) dynamos to the cross-polar potential drop. Convection streamlines which are connected to the high-latitude dynamo may be identified from dispersed magnetosheath ions not only in the cusp/cleft region itself but also several degrees poleward of it. This fact, together with Freja's orbital geometry allows us to infer the potential drop from the high-latitude dynamo as well as to obtain a lower limit to the potential drop from the low-latitude dynamo for dayside Freja passes. All cases studied here are for active magnetospheric conditions. The Freja data suggest that under these conditions at least one third of the potential is generated in the low-latitude dynamo. These observations are consistent with earlier observations of the potential across the low-latitude boundary layer if we assume that the low-latitude dynamo region extends over several tens of Earth radii in the antisunward direction along the tail flanks, and that the majority of the potential drop derives from the sun-aligned component of the electric field rather than from its cross-boundary component, or equivalently, that the centre of the dynamo region is located quite far down tail. A possible dynamo geometry is illustrated.

  • 188.
    Blomqvist, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologi och geokemi.
    Geochemistry of coastal Baltic sediments: processes and sampling procedures1992Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Quantitative and experimental studies on Recent sedimentary processes, with particular reference to element dynamics and mass transport, were conducted in a coastal area of the north-western Baltic proper. A five-year geochemical study reports sediment trap catches, and estimates the flux dynamics of resuspended sediments and primary settling matter. Considerable variations within and between years, seasons and nearby stations were revealed for gross sedimentation rate, and for the ratio between primary settling matter and resuspended sediment. This pattern also applied to carbon. Resuspended matter was found to be a large item in the annual budget for all years and stations. In fact, the resuspended portion commonly exceeded 50 %, and periods without resuspension seem rarely or never to occur in the investigated area. Dominance of primary settling matter was recorded mainly in spring. These findings illustrate problems that may be caused by the use of coastal marine data onsettling flux uncorrected for the resuspended portion. These conclusions are based on analyses of petrogenic elements, and their use as markers, to derive quantitative estimates of the origin of the intercepted matter. A second geochemical paper also deals with petrogenic elements, and illustrates the importance of considering natural geochemical variation in sediments when assessing changes in metal loading. Conclusions drawn in these two papers may have implications for much geochemical, ecological and environmental research in coastal areas. The credibility of these geochemical conclusions depend critically on the use of reliable and dependable sedimentological field sampling techniques. The methods used were selected after extensive evaluations of available methods and instruments. These evaluations include an insitu experiment on the dependence of the orifice area of the collecting tubes on sediment trapping, and studies on soft bottom sediment sampling, and the biases caused by coreshortening, redistribution, resuspension and loss of enclosed sediments. Newly designed instruments for acquisition of sediments and a new sediment trap system are described. The methodological evaluations also involve two review papers, one on the sediment trap technique and one on quantitative sampling of soft-bottom sediments.

  • 189.
    Blum, Kristin M.
    et al.
    Umea Univ, Dept Chem, S-90187 Umea, Sweden..
    Norström, Sara H.
    Umea Univ, Dept Chem, S-90187 Umea, Sweden..
    Golovko, Oksana
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Grabic, Roman
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Järhult, Josef D.
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinska vetenskaper, Infektionssjukdomar. Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Medicinska fakulteten, Institutionen för medicinsk biokemi och mikrobiologi.
    Koba, Olga
    Univ South Bohemia Ceske Budejovice, Fac Fisheries & Protect Waters, South Bohemian Res Ctr Aquaculture & Biodivers Hy, Zatisi 728-2, Vodnany 38925, Czech Republic..
    Söderström Lindström, Hanna
    Umea Univ, Dept Chem, S-90187 Umea, Sweden.;Umea Univ, Dept Publ Hlth & Clin Med, Occupat & Environm Med, S-90187 Umea, Sweden..
    Removal of 30 active pharmaceutical ingredients in surface water under long-term artificial UV irradiation2017Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 176, s. 175-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study investigated the i) kinetics, and ii) proportion of photolysis of 30 relatively stable active pharmaceutical ingredients (APIs) during artificial UV irradiation for 28 d in ammonium acetate buffer, filtered and unfiltered river water. Buffer was included to control removal kinetics under stable pH conditions and without particulate matter. Dark controls were used to determine removal due to other processes than photolysis and calculate the proportion of photolysis of the total removal. The removal of each API in each matrix was determined using online solid phase extraction/liquid chromatography tandem mass spectrometry (online SPE/LC-MS/MS). Most APIs transformed during the 28 d of UV irradiation and the dark controls showed that photolysis was the major removal process for the majority of the APIs studied. The half-lives ranged from 6 h (amitriptyline) in unfiltered river water to 884 h (37 d, carbamazepine) in buffer. In unfiltered river water, the proportion of APIs with short half-lives (<48 h) was much higher (29%) than in the other matrices (4%), probably due to additional organic carbon, which could have promoted indirect photolysis. Furthermore, two APIs, memantine and fluconazole, were stable in all three matrices, while alprazolam was stable in buffer and unfiltered river water and four additional APIs were stable in buffer. Considering the relatively long-term UV-exposure, this study enabled the investigation of environmentally relevant half-lives in natural waters. Many APIs showed high persistence, which is environmentally concerning and emphasizes the importance of further studies on their environmental fate and effects.

    Ladda ner fulltext (pdf)
    fulltext
    Ladda ner (pdf)
    errata
  • 190.
    Blythe, Lara S.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Understanding Crustal Volatiles: Provenance,  Processes and Implications2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Knowledge of the provenance of crustal volatiles and the processes by which they are released is extremely important for the dynamics of magmatic systems. Presented here are the results of multiple investigations, which aim to understand magmatic volatile contamination from contrasting but complementary perspectives. The main methodologies used include He and C isotope values and CO2/3He ratios of volcanic gases and fluids; simulation of magma-carbonate interaction using high-pressure high-temperature experimental petrology; X-ray microtomography of vesiculated xenoliths and computer modeling.

    Findings show that the contribution from upper crustal volatiles can be substantial, and is dependant on the upper crustal lithology on which a volcano lies, as well as the composition of the magma supplied. Carbonate dissolution in particular is strongly controlled by the viscosity of the host magma. The details of the breakdown of vesiculated xenoliths is complex but has wide reaching implications, ranging from the dissemination of crustally derived materials through a magma body to highlighting that crustal volatiles are largely unaccounted for in both individual volcano and global volatile budgets. In synthesizing the conclusions from each of the individual perspectives presented, I propose the contribution of volatiles from crustal sources to play a significant role in many geological systems. This volatile component should be taken into consideration in future research efforts.

    Ladda ner fulltext (pdf)
    fulltext
  • 191.
    Blythe, Lara
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Troll, Valentin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Berggrundsgeologi.
    Hilton, David
    Geosciences Research Division, Scripps Institution of Oceanography.
    Schwarzkopf, Lothar
    Geo Doc Con, Unterpferdt 8, 95176, Konradsreuth, Germany.
    Mantle versus crustal volatile sources along the Java – Bali segment of the Sunda arc, Indonesia.Manuskript (preprint) (Övrigt vetenskapligt)
  • 192.
    Boesen, Amanda H.
    et al.
    Department of Forestry and Wildlife Management, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Koppang, Norway.
    Thiel, Alexandra
    Department of Forestry and Wildlife Management, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Koppang, Norway.
    Fuchs, Boris
    Department of Forestry and Wildlife Management, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Koppang, Norway.
    Evans, Alina L.
    Department of Forestry and Wildlife Management, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Koppang, Norway.
    Bertelsen, Mads F.
    Center for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark.
    Rodushkin, Ilia
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik. ALS Scandinavia AB.
    Arnemo, Jon M.
    Department of Forestry and Wildlife Management, Faculty of Applied Ecology, Agricultural Sciences and Biotechnology, Inland Norway University of Applied Sciences, Koppang, Norway. Department of Wildlife, Fish and Environmental Studies, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden.
    Assessment of the LeadCare® Plus for Use on Scandinavian Brown Bears (Ursus arctos)2019Ingår i: Frontiers in Veterinary Science, ISSN 2297-1769, Vol. 6, artikel-id 285Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Lead (Pb) exposure is associated with adverse health effects in both humans and wildlife. Blood lead levels (BLL) of sentinel wildlife species can be used to monitor environmental lead exposure and ecosystem health. BLL analyzers, such as the LeadCare (R), are validated for use in humans, assessed for use in some avian species and cattle, and are increasingly being used on wildlife to monitor lead exposure. The LeadCare (R) analyzers use a technique called anodic stripping voltammetry (ASV). Species-specific conversion equations have been proposed to approximate the levels found with gold standard measuring methods such as inductively coupled plasma mass spectrometry (ICP-MS) because the ASV method has been shown to underestimate BLL in some species. In this study we assessed the LeadCare (R) Plus (LCP) for use on Scandinavian brown bears (Ursus arctos). LCP measurements were correlated with ICP-MS with a Bland-Altman analyzed bias of 16.3-22.5%, showing a consistent overestimation of BLL analyzed with LCP. Based on this analysis we provide conversion equations for calculating ICP-MS BLL based on the LCP results in Scandinavian brown bears. Our study shows that the LeadCare (R) Plus can be used for monitoring of lead exposure by approximating gold standard levels using conversion equations. This enables comparison with other gold standard measured BLL within the observed range of this study (38.20-174.00 mu g/L). Our study also found that Scandinavian brown bears are highly exposed to environmental lead.

  • 193. Bolhar, R.
    et al.
    Hofmann, A.
    Kemp, A.I.S.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Wind, S.
    Kamber, B.S.
    Juvenile crust formation in the Zimbabwe Craton deduced from the O-Hf isotopic record of 3.8-3.0 Ga detrital zircons2017Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 215, s. 432-446Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hafnium and oxygen isotopic compositions measured in-situ on U-Pb dated zircon from Archaean sedimentary successions belonging to the 2.9–2.8 Ga Belingwean/Bulawayan groups and previously undated Sebakwian Group are used to characterize the crustal evolution of the Zimbabwe Craton prior to 3.0 Ga. Microstructural and compositional criteria were used to minimize effects arising from Pb loss due to metamorphic overprinting and interaction with low-temperature fluids. 207Pb/206Pb age spectra (concordance >90%) reveal prominent peaks at 3.8, 3.6, 3.5, and 3.35 Ga, corresponding to documented geological events, both globally and within the Zimbabwe Craton. Zircon δ18O values from +4 to +10‰ point to both derivation from magmas in equilibrium with mantle oxygen and the incorporation of material that had previously interacted with water in near-surface environments. In εHf-time space, 3.8–3.6 Ga grains define an array consistent with reworking of a mafic reservoir (176Lu/177Hf ∼0.015) that separated from chondritic mantle at ∼3.9 Ga. Crustal domains formed after 3.6 Ga depict a more complex evolution, involving contribution from chondritic mantle sources and, to a lesser extent, reworking of pre-existing crust. Protracted remelting was not accompanied by significant mantle depletion prior to 3.35 Ga. This implies that early crust production in the Zimbabwe Craton did not cause complementary enriched and depleted reservoirs that were tapped by later magmas, possibly because the volume of crust extracted and stabilised was too small to influence (asthenospheric) mantle isotopic evolution. Growth of continental crust through pulsed emplacement of juvenile (chondritic mantle-derived) melts, into and onto the existing cratonic nucleus, however, involved formation of complementary depleted subcontinental lithospheric mantle since the early Archaean, indicative of strongly coupled evolutionary histories of both reservoirs, with limited evidence for recycling and lateral accretion of arc-related crustal blocks until 3.35 Ga.

  • 194. Bollard, J.
    et al.
    Connelly, J.N.
    Whitehouse, Martin J.
    Naturhistoriska riksmuseet, Enheten för geovetenskap.
    Pringle, E.A.
    Bonal, E.A.
    Jørgensen, J.K.
    Nordlund, Å.
    Moynier, F.
    Bizzarro, M.
    Early formation of planetary building blocks inferred from Pb isotopic ages of chondrules.2017Ingår i: Science Advances, ISSN 2375-2548, Vol. 3, artikel-id e1700407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The most abundant components of primitive meteorites (chondrites) are millimeter-sized glassy spherical chondrules formed by transient melting events in the solar protoplanetary disk. Using Pb-Pb dates of 22 individual chondrules, we show that primary production of chondrules in the early solar system was restricted to the first million years after the formation of the Sun and that these existing chondrules were recycled for the remaining lifetime of the protoplanetary disk. This finding is consistent with a primary chondrule formation episode during the early high-mass accretion phase of the protoplanetary disk that transitions into a longer period of chondrule reworking. An abundance of chondrules at early times provides the precursor material required to drive the efficient and rapid formation of planetary objects via chondrule accretion.

    Ladda ner fulltext (pdf)
    fulltext
  • 195.
    Boman, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Engström, Emma
    Rodushkin, Ilya
    ALS Scandinavia AB.
    Åström, E.M.
    Linnaeus University, School of Natural Sciences, Kalmar.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fe and Zn isotopic variations in Finnish acid sulfate soils2010Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, nr 12/ Suppl 1, s. A102-Artikel i tidskrift (Övrigt vetenskapligt)
  • 196. Boman, Anton
    et al.
    Engström, Emma
    Rodushkin, Ilya
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Åström, Mats
    Linnéuniversitetet.
    Öhlander, Björn
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Isotopic variations of Fe and Zn in Finnish acid sulfate soils2010Ingår i: Proceedings of the 19th World Congress of Soil Science: Soil Solutions for a Changing World / [ed] RJ Gilkes; N Prakongkep, 2010, s. 1-4Konferensbidrag (Refereegranskat)
    Abstract [en]

    The use of a Neptune high-resolution MC-ICP-MS (Thermo Fisher Scientific) in this study has enabled high precision measurements of Fe and Zn isotopic ratios in Finnish acid sulfate soils in one near shore area (Vassor) and one inland area (Rintala).

    Ladda ner fulltext (pdf)
    FULLTEXT01
  • 197.
    Boman, Anton
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Geovetenskap och miljöteknik.
    Fröjdö, Sören
    Åbo Akademi University.
    Backlund, Krister
    Åbo Akademi University.
    Åström, Mats E.
    Linnaeus University.
    Impact of isostatic land uplift and artificial drainage on oxidation of brackish-water sediments rich in metastable iron sulfide2010Ingår i: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 1872-9533, Vol. 74, nr 4, s. 1268-1281Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study examines the dynamics of sulfur and trace elements (As, Co, Mo, Ni, Ti and Zn) when brackish-water sediments, unusually rich in metastable iron sulfide (probably a mixture of mackinawite and greigite), are brought into the oxidation zone by postglacial isostatic land uplift and farmland drainage. When subaqueous sediments approach the sea level, metastable iron sulfide is oxidized in the upmost layers and pyrite preserved and even accumulated concomitantly trapping Co, Ni and Zn but not As and Mo. When the land uplift has brought the sediments above sea level and natural drainage thus is initiated, the pyrite is oxidized and Co, Ni and Zn are released and transported down the profile. If this setting remained undisturbed, the slightly oxidized sediment (unripe soil) would become covered by peat and thus protected from further oxidation and metal translocation. Often these sediments are, however, artificially drained resulting in extensive oxidation and fast soil-profile development. The soil is an acid sulfate (AS) soil, characterized by low pH (<4), extensive leaching of metals and an abundance of disseminated brownish Fe(III) precipitates. We suggest that the fast soil development is due to initial oxidation of metastable iron sulfide, followed by pyrite oxidation. Drain bottom sediment, which in terms of chemistry and S-isotopes resembled that of the surfacing sea bottom strata, acted during the sampling period as a sink for metals. The abundant preservation of metastable iron sulfide below the groundwater table, even long periods after uplift above the sea level, is a puzzling feature. We suggest that it is the net result of sulfur starvation, an abundance of Fe(II) and strongly reducing conditions.

  • 198.
    Bonaglia, Stefano
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Benthic metabolism and sediment nitrogen cycling in Baltic sea coastal areas: the role of eutrophication, hypoxia and bioturbation2012Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Eutrophication is one of the greatest threats for the Baltic Sea, and one of its more critical consequences is bottom water hypoxia. Nutrient enrichment and oxygen-depletion affect both the deep central basins and a number of coastal areas, even though strategies for nutrient reduction have lately been implemented. In order to better understand why those threats are expanding and formulate more effective remediation strategies two main achievements are needed: (1) new data on benthic nutrient dynamics should be available in order to develop updated budgets for sensitive Baltic areas; (2) the main transformation processes and their regulation mechanisms (i.e. oxygen availability, presence of macrofauna, different organic loading scenarios) should be better constrained.

    Paper I was able to demonstrate that re-oxygenation of previously anoxic sediment has a positive effect on the ecosystem because of better retention of nutrients and efficient conversion of fixed nitrogen to nitrogen gas. Sediment colonization by the invasive genus Marenzelleria counteracts some of the positive aspects provided by benthic oxygenation (in particular, nutrient retention, N2 loss). A possible explanation for this reversal can be that Marenzelleria does stimulate anaerobic more that aerobic metabolism.

    Results from Paper II suggest that at the outermost stations of Himmerfjärden denitrification follows a pronounced seasonal pattern, primarily regulated by bottom water temperatures. At the innermost and impacted site oxygen level in the bottom water varies considerably during the year and causes denitrification/DNRA predominance to be the main nitrate reduction pathway. On an annual scale, the net amount of lost N2 is comparable at the four sampling sites and accounts for 96% of the total DIN discharged from the sewage treatment plant, suggesting that denitrification in the estuarine sediment acts as a major nitrogen sink for external N inputs.

    Ladda ner fulltext (pdf)
    Comprehensive Summary
  • 199.
    Bonaglia, Stefano
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Control factors of the marine nitrogen cycle: The role of meiofauna, macrofauna, oxygen and aggregates2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The ocean is the most extended biome present on our planet. Recent decades have seen a dramatic increase in the number and gravity of threats impacting the ocean, including discharge of pollutants, cultural eutrophication and spread of alien species. It is essential therefore to understand how different impacts may affect the marine realm, its life forms and biogeochemical cycles. The marine nitrogen cycle is of particular importance because nitrogen is the limiting factor in the ocean and a better understanding of its reaction mechanisms and regulation is indispensable. Furthermore, new nitrogen pathways have continuously been described. The scope of this project was to better constrain cause-effect mechanisms of microbially mediated nitrogen pathways, and how these can be affected by biotic and abiotic factors.

    This thesis demonstrates that meiofauna, the most abundant animal group inhabiting the world’s seafloors, considerably alters nitrogen cycling by enhancing nitrogen loss from the system. In contrast, larger fauna such as the polychaete Marenzelleria spp. enhance nitrogen retention, when they invade eutrophic Baltic Sea sediments. Sediment anoxia, caused by nutrient excess, has negative consequences for ecosystem processes such as nitrogen removal because it stops nitrification, which in turn limits both denitrification and anammox. This was the case of Himmerfjärden and Byfjord, two estuarine systems affected by anthropogenic activities, such as treated sewage discharges. When Byfjord was artificially oxygenated, nitrate reduction mechanisms started just one month after pumping. However, the balance between denitrification and nitrate ammonification did not favor either nitrogen removal or its retention.

    Anoxia is also present in aggregates of the filamentous cyanobacteria Nodularia spumigena. This thesis shows that even in fully oxic waters, millimetric aggregates can host anaerobic nitrogen processes, with clear implications for the pelagic compartment. While the thesis contributed to our knowledge on marine nitrogen cycling, more data need to be collected and experiments performed in order to understand key processes and regulation mechanisms of element cycles in the ocean. In this way, stakeholders may follow and take decisions in order to limit the continuous flow of human metabolites and impacts on the marine environment.

    Ladda ner fulltext (pdf)
    fulltext
    Ladda ner (jpg)
    omslagsframsida
  • 200.
    Bonaglia, Stefano
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Deutsch, Barbara
    Bartoli, Marco
    Brüchert, Volker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Seasonal benthic nutrient cycling in a Baltic sea estuary2012Ingår i: / [ed] The Oceanography Society, American Society of Limnology and Oceanography, American Geophysical Union, 2012Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Decades of urban, industrial, and agricultural discharge of nitrogen and phosphorus to the Baltic Sea have contributed to the spreading of water column hypoxia and annual widespread cyanobacteria blooms. Central to mitigating Baltic Sea eutrophication is to resolve how much reduction strategies of external N and P loading are offset by internal loading of the Baltic through nutrient recycling from the sediment. We investigated the seasonal variation of benthic nitrogen and phosphorus cycling in an estuary of the Baltic impacted by decades of sewage discharge. Sediment nutrient fluxes, denitrification, Anammox, DNRA, potential nitrification, and total and diffusive oxygen uptake (TOU/DOU) were quantified with 15N-tracer methods and microsensor profiling. Data indicate benthic net efflux of ammonium and phosphorus during the summer months, decreasing N2 loss with increasing organic matter content, and benthic N/P regeneration with a ratio of 3 to 7 compared to the sewage discharge N/P of ≈ 25, and a significant contribution (6 to 25%) of Anammox to N2 loss. On average benthic denitrification and Anammox may reduce the N load to the estuary by up to 54%.

1234567 151 - 200 av 1734
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