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  • 301.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Elmgren, Ragnar
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Do deposit-feeders compete? Isotopic niche analysis of an invasion in a species-poor system2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 9715Article in journal (Refereed)
    Abstract [en]

    Successful establishment of invasive species is often related to the existence of vacant niches. Competition occurs when invaders use the same limiting resources as members of the recipient community, which will be reflected in some overlap of their trophic niches. The concept of isotopic niche has been used to study trophic niche partitioning among species. Here, we present a two-year field study comparing isotopic niches of the deposit-feeding community in a naturally species-poor system. The isotopic niche analyses showed no overlap between a recent polychaete invader and any of the native species suggesting that it has occupied a vacant niche. Its narrow isotopic niche suggests specialized feeding, however, the high delta N-15 values compared to natives are most likely due to isotope fractionation effects related to nitrogen recycling and a mismatch between biological stoichiometry of the polychaete and the sediment nitrogen content. Notably, highly overlapping isotopic niches were inferred for the native species, which is surprising in a food-limited system. Therefore, our results demonstrate that invaders may broaden the community trophic diversity and enhance resource utilization, but also raise questions about the congruence between trophic and isotopic niche concepts and call for careful examination of assumptions underlying isotopic niche interpretation.

  • 302.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Niemand, Clarisse
    Savage, Candida
    Pilditch, Conrad A.
    Density of Key-Species Determines Efficiency of Macroalgae Detritus Uptake by Intertidal Benthic Communities2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 7, article id e0158785Article in journal (Refereed)
    Abstract [en]

    Accumulating evidence shows that increased biodiversity has a positive effect on ecosystem functioning, but the mechanisms that underpin this positive relationship are contentious. Complete extinctions of regional species pools are comparatively rare whereas compositional changes and reductions in abundance and biomass are common, although seldom the focus of biodiversity-ecosystem functioning studies. We use natural, small-scale patchiness in the density of two species of large bivalves with contrasting feeding modes (the suspension-feeding Austrovenus stutchburyi and deposit-feeding Macomona liliana) to examine their influence on the uptake of nitrogen from macroalgae detritus (i.e. measure of ecosystem function and food web efficiency) by other infauna in a 10-d laboratory isotope-tracer experiment. We predicted that densities of these key bivalve species and functional group diversity (calculated as Shannons H, a density-independent measure of community composition) of the intact infaunal community will be critical factors explaining variance in macroalgal per capita uptake rates by the community members and hence determine total uptake by the community. Results show that only two species, M. liliana and a large orbiniid polychaete (Scoloplos cylindrifer) dominated macroalgal nitrogen taken up by the whole community due to their large biomass. However, their densities were mostly not important or negatively influenced per capita uptake by other species. Instead, the density of a head-down deposit-feeder (the capitellid Heteromastus filiformis), scavengers (mainly nemertines and nereids) and species and functional group diversity, best explained per capita uptake rates in community members. Our results demonstrate the importance of species identity, density and large body size for ecosystem functioning and highlight the complex interactions underlying loss of ecological functions with declining biodiversity and compositional changes.

  • 303.
    Karlson, Agnes M. L.
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Reutgard, Martin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Isotopic niche reflects stress-induced variability in physiological status2018In: Royal Society Open Science, E-ISSN 2054-5703, Vol. 5, no 2, article id 171398Article in journal (Refereed)
    Abstract [en]

    The isotopic niche has become an established concept in trophic ecology. However, the assumptions behind this approach have rarely been evaluated. Evidence is accumulating that physiological stress can affect both magnitude and inter-individual variability of the isotopic signature in consumers via alterations in metabolic pathways. We hypothesized that stress factors (inadequate nutrition, parasite infestations, and exposure to toxic substances or varying oxygen conditions) might lead to suboptimal physiological performance and altered stable isotope signatures. The latter can be misinterpreted as alterations in isotopic niche. This hypothesis was tested by inducing physiological stress in the deposit-feeding amphipod Monoporeia affinis exposed to either different feeding regimes or contaminated sediments. In the amphipods, we measured body condition indices or reproductive output to assess growth status and delta C-13 and delta N-15 values to derive isotope niche metrics. As hypothesized, greater isotopic niche estimates were derived for the stressed animals compared to the control groups. Moreover, the delta N-15 values were influenced by body size, reproductive status and parasite infestations, while delta C-13 values were influenced by body size, oxygen conditions and survival. Using regression analysis with isotope composition and growth variables as predictors, we were able to discriminate between the amphipods exposed to nutritionally or chemically stressful conditions and those in the control groups. Thus, interpretation of isotopic niche can be confounded by natural or anthropogenic stressors that may induce an apparent change in isotopic niche. These findings stress the importance of including measures of growth and health status when evaluating stable isotope data in food web studies.

  • 304.
    Karlsson, Emma
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Compositional clues to sources and sinks of terrestrial organic matter transported to the Eurasian Arctic shelf2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The amount of organic carbon (OC) present in Siberian Arctic permafrost soils is estimated at twice the amount of carbon currently in the atmosphere. The shelf seas of the Arctic Ocean receive large amounts of this terrestrial OC from Eurasian Arctic rivers and from coastal erosion. Degradation of this land-derived material in the sea would result in the production of dissolved carbon dioxide and may then add to the atmospheric carbon dioxide reservoir. Observations from the Siberian Arctic suggest that transfer of carbon from land to the marine environment is accelerating. However, it is not clear how much of the transported OC is degraded and oxidized, nor how much is removed from the active carbon cycle by burial in marine sediment.

    Using bulk geochemical parameters, total OC, d13C and D14C isotope composition, and specific molecular markers of plant wax lipids and lignin phenols, the abundance and composition of OC was determined in both dissolved and particulate carrier phases: the colloidal OC (COC; part of the dissolved OC), particulate OC (POC), and sedimentary OC (SOC). Statistical modelling was used to quantify the relative contribution of OC sources to these phases. Terrestrial OC is derived from the seasonally thawing top layer of permafrost soil (topsoil OC) and frozen OC derived from beneath the active layer eroded at the coast, commonly identified as yedoma ice complex deposit OC (yedoma ICD-OC). These carbon pools are transported differently in the aquatic conduits. Topsoil OC was found in young DOC and POC, in the river water, and the shelf water column, suggesting long-distance transport of this fraction. The yedoma ICD-OC was found as old particulate OC that settles out rapidly to the underlying sediment and is laterally transported across the shelf, likely dispersed by bottom nepheloid layer transport or via ice rafting.

    These two modes of OC transport resulted in different degradation states of topsoil OC and yedoma ICD-OC. Terrestrial CuO oxidation derived biomarkers indicated a highly degraded component in the COC. In contrast, the terrestrial component of the SOC was much less degraded. In line with earlier suggestions the mineral component in yedoma ICD functions as weight and surface protection of the associated OC, which led to burial in the sediment, and limited OC degradation. The degradability of the terrestrial OC in shelf sediment was also addressed in direct incubation studies. Molecular markers indicate marine OC (from primary production) was more readily degraded than terrestrial OC. Degradation was also faster in sediment from the East Siberian Sea, where the marine contribution was higher compared to the Laptev Sea. Although terrestrial carbon in the sediment was degraded slower, the terrestrial component also contributed to carbon dioxide formation in the incubations of marine sediment.

    These results contribute to our understanding of the marine fate of land-derived OC from the Siberian Arctic. The mobilization of topsoil OC is expected to grow in magnitude with climate warming and associated active layer deepening. This translocated topsoil OC component was found to be highly degraded, which suggests degradation during transport and a possible contribution to atmospheric carbon dioxide. Similarly, the yedoma ICD-OC (and or old mineral soil carbon) may become a stronger source with accelerated warming, but slow degradation may limit its impact on active carbon cycling in the Siberian Shelf Seas.

  • 305.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Alling, Vanja
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    van Dongen, Bart
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Manchester, UK.
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Contrasting sources of dissolved and particulate organic matter along 62N-72N in the Siberian-Arctic Lena RiverManuscript (preprint) (Other academic)
    Abstract [en]

    The Lena River transports large amounts of sediment and dissolved organic matter to the shallow Laptev Sea, where it may be subject to degradation and potential release of OC. We studied organic matter collected in summer 2008, along a 1450 km section of the Lena River, from near Yakutsk at 62°N to the deltaic region at 72°N, to better understand potential in-river processing of the terrestrial particulate and dissolved fractions in the river surface water.

    Carbon isotopes (δ13C and Δ14C) and plant wax lipid markers combine to reveal two distinct OC pools with different behavior in the river. The molar OC/TN ratios for POC were low (6-13) which suggests contribution from (freshwater) plankton, but most of the POC was of old age (770-4500 14C years) which rather suggests a pre-aged origin - perhaps from erosion of riverbank permafrost material. Much in contrast, COC was young (20-440 14C years) and displayed a high OC/TN composition (23-56) with a steady δ13C signal along the river course (-26.7 to -27.7). There was an apparent absence of ice complex deposit permafrost (mineral soil/yedoma OC) in the COC fraction, and only small contributions to POC. The COC signal suggest contribution from contemporary plant detritus/surface soil OC. It seems as if pre-aged permafrost OC, potentially from riverbank erosion, partitions into the particulate pool and almost not at all to the DOC/COC pool.

    Degradation markers indicate a highly degraded COC lipid pool and a less degraded POC - the n-alkane carbon preference index (CPI, C24-C34) was 1.0-1.3 for COC and 1.2-4.9 (on average 3.3) for POC.

    Taken together DOC/COC and POC have clearly different terrestrial sources and different fates on its way to the shelf waters. Previously freeze-locked old permafrost OC remobilizes into the Lena River in particulate form which (at least temporarily) escapes degradation as it follows the river course seawards in a less degraded state.

  • 306.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gelting, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Institute of Marine Sciences, Italy.
    van Dongen, Bart
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Orjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Different sources and degradation state of dissolved, particulate, and sedimentary organic matter along the Eurasian Arctic coastal margin2016In: Global Biogeochemical Cycles, ISSN 0886-6236, E-ISSN 1944-9224, Vol. 30, no 6, p. 898-919Article in journal (Refereed)
    Abstract [en]

    Thawing Arctic permafrost causes massive fluvial and erosional releases of dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and degradation of remobilized terrestrial carbon may affect large-scale carbon cycling, by comparing molecular and dual-isotope composition of waterborne high molecular weight DOC (>1kD, aka colloidal OC), POC, and sedimentary OC (SOC) across the East Siberian Arctic Shelves. Lignin phenol fingerprints demonstrate a longitudinal trend in relative contribution of terrestrial sources to coastal OC. Wax lipids and cutins were not detected in colloidal organic carbon (COC), in contrast to POC and SOC, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases. The C-14 signal suggests overwhelmingly contemporary sources for COC, while POC and SOC are dominated by old C from Ice Complex Deposit (ICD) permafrost. Monte Carlo source apportionment (C-13, C-14) constrained that COC was dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution ICD and other older permafrost stocks (9%). This distribution is likely a result of inherent compositional matrix differences, possibly driven by organomineral associations. Modern OC found suspended in the surface water may be more exposed to degradation, in contrast to older OC that preferentially settles to the seafloor where it may be degraded on a longer timescale. The different sources which partition into DOC, POC, and SOC appear to have vastly different fates along the Eurasian Arctic coastal margin and may possibly respond on different timescales to climate change.

  • 307.
    Karlsson, Emma
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Gelting, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    van Dongen, Bart
    Semiletov, Igor
    Charkin, Alexander
    Dudarev, Oleg
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Different sources and degradation state of dissolved, particulate and sedimentary organic matter along the Eurasian Arctic coastal marginManuscript (preprint) (Other academic)
    Abstract [en]

    Thawing of permafrost in the Eurasian Arctic causes massive fluvial and erosional releases of both dissolved and particulate organic carbon (DOC and POC) to coastal waters. Here we investigate how different sources and extent of degradation of remobilized terrestrial carbon pools imprint on major recipient carbon pools and thereby affect large-scale carbon cycling.  The molecular and dual-isotope composition is compared with source end-member composition in waterborne high-molecular weight DOC (>1kD, a.k.a. colloidal OC), POC and in sedimentary OC (SOC) along coastal Kara, Laptev and East Siberian Seas.

    The lignin phenol fingerprint demonstrates a clear geospatial trend in the relative contribution of different terrestrial sources to coastal OC in going from the west to the east.  The wax lipids and cutins were much less abundant in the COC compared to in the POC and SOC compartment, suggesting that different terrestrial carbon pools partition into different aquatic carrier phases.  The Δ14C signal suggests that the COC is overwhelmingly derived from contemporary carbon sources. Furthermore, degradation proxies based on terrestrial lignin phenol biomarkers suggest a highly degraded COC composition. Monte Carlo based source apportionment simulations of the δ13C/Δ14C composition constrained that the COC is dominated by terrestrial OC from topsoil permafrost (65%) and marine plankton (25%) with smaller contribution from Ice Complex Deposit (ICD) and other older stocks of permafrost carbon (9%). This contrasts starkly to the POC and especially the SOC compartment, which are dominated by old C from ICD-OC permafrost.

    These results combine with other recent studies to suggest a pattern along the East Siberian Arctic margin of SOC being constantly older yet less degraded than water column POC. This study also extends this perspective spatially along the Eurasian Arctic seaboard and also to the large COC (HMW DOC) pool, which is even younger yet even more degraded than the POC. An implication is that DOC and POC pools need to be treated separately in assessments of effects on the large-scale carbon cycle (and climate feedback) of old carbon released from thawing permafrost to aquatic receptors across the Eurasian Arctic coast. 

  • 308.
    Karlsson, Emma S.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bruchert, Volker
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Charkin, A.
    Dudarev, O.
    Semiletov, I.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Contrasting regimes for organic matter degradation in the East Siberian Sea and the Laptev Sea assessed through microbial incubations and molecular markers2015In: Marine Chemistry, ISSN 0304-4203, E-ISSN 1872-7581, Vol. 170, p. 11-22Article in journal (Refereed)
    Abstract [en]

    Compositional studies of organic matter on the East Siberian Arctic Shelf (ESAS) suggest that different terrestrial carbon pools have different propensities for transport and/or degradation. The current study combined laboratory-based microbial degradation experiments with earlier published degradation-diagnostic composition of several classes of terrestrial biomarkers on the same sediments to investigate differences and driving forces of terrestrial organic matter (TerrOM) degradation in two biogeochemically-contrasting regimes of the ESAS. The incubation-based anaerobic degradation rates were consistently higher (by average factor of 6) in the East Siberian Sea Kolyma Paleoriver Channel (ESS-KPC) (15 mu mol CO2 g OC-1 day(-1)) compared to the Laptev Sea Buor-Khaya Bay (LS-BKB) (2.4 mu mol CO2 g OC-1 day(-1)). The reported molecular markers show similarities between the terrestrial carbon pools in the two systems, but impose contrasting degradation regimes in combination with the incubation results. For the LS-BKB, there was a strong relationship between the degradation rates and the three lignin phenol-based degradation proxies (r(2) = 0.93-0.96, p < 0.01, linear regression) and two wax lipid-based degradation proxies (r(2) = 0.71 and 0.66, p < 0.05, linear regression). In contrast, for the ESS-KPC system, there was no relationship between incubation-based degradation rates and molecular marker-based degradation status of TerrOM. A principal component analysis indicated that short-chain fatty acids and dicarboxylic acids from CuO oxidation are mainly of terrestrial origin in the LS-BKB, but mainly of marine origin in the ESS-KPC. Hence, the microbial degradation in the western (LS-BKB) system appears to be fueled by TerrOM whereas the eastern (ESS-KPC) system degradation appears to be driven by MarOM. By combining molecular fingerprinting of TerrOM degradation state with laboratory-based degradation studies on the same ESAS sediments, a picture evolves of two distinctly different modes of TerrOM degradation in different parts of the ESAS system.

  • 309.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ndreu, Lorena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Quaranta, Alessandro
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Thorsén, Gunnar
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Glycosylation patterns of selected proteins in individual serum and cerebrospinal fluid samples2017In: Journal of Pharmaceutical and Biomedical Analysis, ISSN 0731-7085, E-ISSN 1873-264X, Vol. 145, p. 431-439Article in journal (Refereed)
    Abstract [en]

    A method we previously developed has been applied to the determination of the glycosylation pattern of specific proteins in biological samples. Six proteins (alpha-1-anthrypsin, transferrin, haptoglobin, Cl inhibitor, alpha-1 acid glycoprotein, and immunoglobulin G) were studied in serum samples from five individuals and cerebrospinal fluid (CSF) samples from three individuals, to investigate the expected normal distribution of glycosylation patterns and to assess whether this methodology can be used to discriminate between samples from different individuals. For serum samples, the differences were shown to be small, while much larger differences were found for the CSF samples, with a greater number of glycoforms present. This can be linked to the occurrence of differential glycosylation in proteins expressed in the brain compared with proteins expressed elsewhere in the body. The developed method could distinguish differences in the glycosylation pattern of specific proteins in the individual samples, which was not reflected in the glycan content of total CSF. This is the first time that the glycoforms of several of these proteins have been investigated in CSF.

  • 310.
    Karlsson, Isabella
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Samuelsson, Kristin
    Simonsson, Carl
    Stenfeldt, Anna-Lena
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Jonsson, Charlotte
    Karlberg, Ann-Therese
    The Fate of a Hapten - From the Skin to Modification of Macrophage Migration Inhibitory Factor (MIF) in Lymph Nodes2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 2895Article in journal (Refereed)
    Abstract [en]

    Skin (contact) allergy, the most prevalent form of immunotoxicity in humans, is caused by low molecular weight chemicals (haptens) that penetrate stratum corneum and modify endogenous proteins. The fate of haptens after cutaneous absorption, especially what protein(s) they react with, is largely unknown. In this study the fluorescent hapten tetramethylrhodamine isothiocyanate (TRITC) was used to identify hapten-protein conjugates in the local lymph nodes after topical application, as they play a key role in activation of the adaptive immune system. TRITC interacted with dendritic cells but also with T and B cells in the lymph nodes as shown by flow cytometry. Identification of the most abundant TRITC-modified protein in lymph nodes by tandem mass spectrometry revealed TRITC-modification of the N-terminal proline of macrophage migration inhibitory factor (MIF) - an evolutionary well-conserved protein involved in cell-mediated immunity and inflammation. This is the first time a hapten-modified protein has been identified in lymph nodes after topical administration of the hapten. Most haptens are electrophiles and can therefore modify the N-terminal proline of MIF, which has an unusually reactive amino group under physiological conditions; thus, modification of MIF by haptens may have an immunomodulating role in contact allergy as well as in other immunotoxicity reactions.

  • 311. Karlsson, Oskar
    et al.
    Jiang, Liying
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ersson, Lisa
    Malmström, Tim
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Brittebo, Eva B.
    Environmental neurotoxin interaction with proteins: Dose-dependent increase of free and protein-associated BMAA (beta-N-methylamino-L-alanine) in neonatal rat brain2015In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 5, article id 15570Article in journal (Refereed)
    Abstract [en]

    beta-Methylamino-L-alanine (BMAA) is implicated in the aetiology of neurodegenerative disorders. Neonatal exposure to BMAA induces cognitive impairments and progressive neurodegenerative changes including intracellular fibril formation in the hippocampus of adult rats. It is unclear why the neonatal hippocampus is especially vulnerable and the critical cellular perturbations preceding BMAA-induced toxicity remains to be elucidated. The aim of this study was to compare the level of free and protein-associated BMAA in neonatal rat brain and peripheral tissues after different exposures to BMAA. Ultra-high performance liquid chromatography-tandem mass spectrometry analysis revealed that BMAA passed the neonatal blood-brain barrier and was distributed to all studied brain areas. BMAA was also associated to proteins in the brain, especially in the hippocampus. The level in the brain was, however, considerably lower compared to the liver that is not a target organ for BMAA. In contrast to the liver there was a significantly increased level of protein-association of BMAA in the hippocampus and other brain areas following repeated administration suggesting that the degradation of BMAA-associated proteins may be lower in neonatal brain than in the liver. Additional evidence is needed in support of a role for protein misincorporation in the neonatal hippocampus for long-term effects of BMAA.

  • 312. Kase, Robert
    et al.
    Korkaric, Muris
    Werner, Inge
    Ågerstrand, Marlene
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Criteria for Reporting and Evaluating ecotoxicity Data (CRED): comparison and perception of the Klimisch and CRED methods for evaluating reliability and relevance of ecotoxicity studies2016In: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 28, article id 7Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: The regulatory evaluation of ecotoxicity studies for environmental risk and/or hazard assessment of chemicals is often performed using the method established by Klimisch and colleagues in 1997. The method was, at that time, an important step toward improved evaluation of study reliability, but lately it has been criticized for lack of detail and guidance, and for not ensuring sufficient consistency among risk assessors.

    RESULTS: A new evaluation method was thus developed: Criteria for Reporting and Evaluating ecotoxicity Data (CRED). The CRED evaluation method aims at strengthening consistency and transparency of hazard and risk assessment of chemicals by providing criteria and guidance for reliability and relevance evaluation of aquatic ecotoxicity studies. A two-phased ring test was conducted to compare and characterize the differences between the CRED and Klimisch evaluation methods. A total of 75 risk assessors from 12 countries participated. Results show that the CRED evaluation method provides a more detailed and transparent evaluation of reliability and relevance than the Klimisch method. Ring test participants perceived it to be less dependent on expert judgement, more accurate and consistent, and practical regarding the use of criteria and time needed for performing an evaluation.

    CONCLUSIONS: We conclude that the CRED evaluation method is a suitable replacement for the Klimisch method, and that its use may contribute to an improved harmonization of hazard and risk assessments of chemicals across different regulatory frameworks.

  • 313. Kerré, B.
    et al.
    Bravo, C. T.
    Leifeld, J.
    Cornelissen, Gerard
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Smolders, E.
    Historical soil amendment with charcoal increases sequestration of non-charcoal carbon: a comparison among methods of black carbon quantification2016In: European Journal of Soil Science, ISSN 1351-0754, E-ISSN 1365-2389, Vol. 67, no 3, p. 324-331Article in journal (Refereed)
    Abstract [en]

    We have shown previously that soil with historical (>150 years) applications of charcoal had larger recent (C4-maize derived) carbon content than adjacent soil; however, we could not determine whether there was an effect on older, C3-plant-derived, soil organic carbon (SOC). Therefore, we assessed the effect of historical additions of charcoal on the sequestration of recent and older SOC with a combination of delta C-13 analysis and different quantification techniques for black carbon (BC): dichromate oxidation (Cr2O7), chemo-thermal oxidation (CTO-285) and differential scanning calorimetry (DSC). Topsoils cropped with maize (Zea mays) under former charcoal production sites (N = 12) were identified in the field as black spots and had a larger (3.5%, P < 0.05) percentage of organic carbon (OC) contents than adjacent soil outside these spots (2.0%). The charcoal content varied with the detection technique used as follows: CTO-285 > DSC > Cr2O7. Black spots contained 1.6-1.7 times more (P < 0.05) maize-derived OC content than adjacent soil, irrespective of the BC quantification technique. The content of non-charcoal OC was 1.0-1.4 times larger in black spots than in adjacent soil, but differences were significant only for the Cr2O7 method. Soil physicochemical fractionation showed that at charcoal production sites more OC was recovered in the particulate organic matter and silt and clay fractions. The delta C-13 analysis suggested that additional maize-OC in black spots was in the physically more protected silt and clay fraction. Overall, this study shows that historical charcoal amendment in soil enhances the accumulation of recent maize-derived OC in a temperate climate without replacing the older C stocks.

  • 314.
    Keshavarzi, Neda
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Mashayekhy Rad, Farshid
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Mace, Amber
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ansari, Farhan
    Akhtar, Farid
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Berglund, Lars
    Bergström, Lennart
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Nanocellulose-Zeolite Composite Films for Odor Elimination2015In: ACS Applied Materials and Interfaces, ISSN 1944-8244, E-ISSN 1944-8252, Vol. 7, no 26, p. 14254-14262Article in journal (Refereed)
    Abstract [en]

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 mu m thick zeolite CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography mass spectroscopy (GC/MS) analysis showed that the CNF zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

  • 315.
    Keskitalo, Kirsi
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Tesi, Tommaso
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. CNR-National Research Council of Italy, Italy.
    Bröder, Lisa
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Andersson, August
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Pearce, Christof
    Stockholm University, Faculty of Science, Department of Geological Sciences.
    Sköld, Martin
    Stockholm University, Faculty of Science, Department of Mathematics.
    Semiletov, Igor P.
    Dudarev, Oleg V.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sources and characteristics of terrestrial carbon in Holocene-scale sediments of the East Siberian Sea2017In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 13, no 9, p. 1213-1226Article in journal (Refereed)
    Abstract [en]

    Thawing of permafrost carbon (PF-C) due to climate warming can remobilise considerable amounts of terrestrial carbon from its long-term storage to the marine environment. PF-C can be then be buried in sediments or remineralised to CO2 with implications for the carbon-climate feedback. Studying historical sediment records during past natural climate changes can help us to understand the response of permafrost to current climate warming. In this study, two sediment cores collected from the East Siberian Sea were used to study terrestrial organic carbon sources, composition and degradation during the past similar to 9500 cal yrs BP. CuO-derived lignin and cutin products (i.e., compounds solely biosynthesised in terrestrial plants) combined with delta C-13 suggest that there was a higher input of terrestrial organic carbon to the East Siberian Sea between similar to 9500 and 8200 cal yrs BP than in all later periods. This high input was likely caused by marine transgression and permafrost destabilisation in the early Holocene climatic optimum. Based on source apportionment modelling using dual-carbon isotope (Delta C-14, Delta C-13) data, coastal erosion releasing old Pleistocene permafrost carbon was identified as a significant source of organic matter translocated to the East Siberian Sea during the Holocene.

  • 316. Kim, Hyunji
    et al.
    Soerensen, Anne L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hur, Jin
    Heimburger, Lars-Eric
    Hahm, Doshik
    Rhee, Tae Siek
    Noh, Seam
    Han, Seunghee
    Methylmercury Mass Budgets and Distribution Characteristics in the Western Pacific Ocean2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 3, p. 1186-1194Article in journal (Refereed)
    Abstract [en]

    Methylmercury (MeHg) accumulation in marine organisms poses serious ecosystem and human health risk, yet the sources of MeHg in the surface and subsurface ocean remain uncertain. Here, we report the first MeHg mass budgets for the Western Pacific Ocean estimated based on cruise observations. We found the major net source of MeHg in surface water to be vertical diffusion from the subsurface layer (1.8-12 nmol m(-2) yr(-1)). A higher upward diffusion in the North Pacific (12 nmol m(-2) yr(-1)) than in the Equatorial Pacific (1.8-5.7 nmol m(-2) yr(-1)) caused elevated surface MeHg concentrations observed in the North Pacific. We furthermore found that the slope of the linear regression line for MeHg versus apparent oxygen utilization in the Equatorial Pacific was about 2-fold higher than that in the North Pacific. We suggest this could be explained by redistribution of surface water in the tropical convergence-divergence zone, supporting active organic carbon decomposition in the Equatorial Pacific Ocean. On the basis of this study, we predict oceanic regions with high organic carbon remineralization to have enhanced MeHg concentrations in both surface and subsurface waters.

  • 317. Knoblauch, Christian
    et al.
    Beer, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Liebner, Susanne
    Grigoriev, Mikhail N.
    Pfeiffer, Eva-Maria
    Methane production as key to the greenhouse gas budget of thawing permafrost2018In: Nature Climate Change, ISSN 1758-678X, E-ISSN 1758-6798, Vol. 8, no 4, p. 309-312Article in journal (Refereed)
    Abstract [en]

    Permafrost thaw liberates frozen organic carbon, which is decomposed into carbon dioxide (CO2) and methane (CH4). The release of these greenhouse gases (GHGs) forms a positive feedback to atmospheric CO2 and CH4 concentrations and accelerates climate change(1,2). Current studies report a minor importance of CH4 production in water-saturated (anoxic) permafrost soils(3-6) and a stronger permafrost carbon-climate feedback from drained (oxic) soils(1,7). Here we show through seven-year laboratory incubations that equal amounts of CO2 and CH4 are formed in thawing permafrost under anoxic conditions after stable CH4-producing microbial communities have established. Less permafrost carbon was mineralized under anoxic conditions but more CO2-carbon equivalents (CO2Ce) were formed than under oxic conditions when the higher global warming potential (GWP) of CH4 is taken into account(8). A model of organic carbon decomposition, calibrated with the observed decomposition data, predicts a higher loss of permafrost carbon under oxic conditions (113 +/- 58 g CO2-C kgC(-1) (kgC, kilograms of carbon)) by 2100, but a twice as high production of CO2-Ce (241 +/- 138 g CO2-Ce kgC(-1)) under anoxic conditions. These findings challenge the view of a stronger permafrost carbon-climate feedback from drained soils1,7 and emphasize the importance of CH4 production in thawing permafrost on climate-relevant timescales.

  • 318. Koch, Josef
    et al.
    Bui, Thuy T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lundström Belleza, Elin
    Brinkmann, Markus
    Hollert, Henner
    Breitholtz, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Temperature and food quantity effects on the harpacticoid copepod Nitocra spinipes: Combining in vivo bioassays with population modeling2017In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 12, no 3, p. 1-18, article id e0174384Article in journal (Refereed)
    Abstract [en]

    The harpacticoid copepod Nitocra spinipes has become a popular model species for toxicity testing over the past few decades. However, the combined influence of temperature and food shortage, two climate change-related stressors, has never been assessed in this species. Consequently, effects of three temperatures (15, 20 and 25 degrees C) and six food regimes (between 0 and 5 x 10(5) algal cells/mL) on the life cycle of N. spinipes were examined in this study. Similarly to other copepod species, development times and brood sizes decreased with rising temperatures. Mortality was lowest in the 20 degrees C temperature setup, indicating a close-by temperature optimum for this species. Decreasing food concentrations led to increased development times, higher mortality and a reduction in brood size. A sex ratio shift toward more females per male was observed for increasing temperatures, while no significant relationship with food concentration was found. Temperature and food functions for each endpoint were integrated into an existing individual-based population model for N. spinipes which in the future may serve as an extrapolation tool in environmental risk assessment. The model was able to accurately reproduce the experimental data in subsequent verification simulations. We suggest that temperature, food shortage, and potentially other climate change-related stressors should be considered in environmental risk assessment of chemicals to account for non-optimal exposure conditions that may occur in the field. Furthermore, we advocate combining in vivo bioassays with population modeling as a cost effective higher tier approach to assess such considerations.

  • 319.
    Konovalenko, Lena
    et al.
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Bradshaw, Clare
    Stockholm University, Faculty of Science, Department of Ecology, Environment and Plant Sciences.
    Andersson, E.
    Lindqvist, Dennis
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kautsky, U.
    Evaluation of factors influencing accumulation of stable Sr and Cs in lake and coastal fish2016In: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 160, p. 64-79Article in journal (Refereed)
    Abstract [en]

    As a result of nuclear accidents and weapons tests, the radionuclides Cs-137 and Sr-90 are common contaminants in aquatic ecosystems. Concentration ratios (CR) based on concentrations of stable Cs and Sr in biota and media are used for the estimation of transfer of their radioisotopes for radiation dose calculations in environmental and human safety assessments. Available element-specific CRs vary by over an order of magnitude for similar organisms, thus affecting the dose estimates proportionally. The variation could be reduced if they were based on a better understanding of the influence of the underlying data and how that affects accumulation and potential biomagnification of stable Cs and Sr in aquatic organisms. For fish, relationships have been identified between water concentrations of K and CR of Cs-137, and between water concentrations of Ca and CR of Sr-90. This has not been confirmed for stable Cs and Sr in European waters. In this study, we analysed an existing dataset for stable Cs and Sr, as well as K and Ca, in four Swedish lakes and three Baltic Sea coastal areas, in order to understand the behaviour of these elements and their radioisotopes in these ecosystems. We found significant seasonal variations in the water concentrations of Cs, Sr, K and Ca, and in electrical conductivity (EC), especially in the lakes. CR values based on measurements taken at single or few time points may, therefore, be inaccurate or introduce unnecessarily large variation into risk assessments. Instead, we recommend incorporating information about the underlying variation in water concentrations into the CR calculations, for example by using the variation of the mean. The inverse relationships between fish CRCs -[K](water) and fish CRSr-[Ca](water), confirmed that stable Cs and Sr follow the same trends as their radioisotopes. Thus, they can be used as proxies when radioisotope data are lacking. EC was also strongly correlated with K and Ca concentrations in the water and could potentially be used as a quick and cost-effective method to estimate water chemistry to obtain less variable CR. We also recommend some simple improvements to data collection that would greatly enhance our ability to understand Cs and Sr uptake by fish.

  • 320.
    Kontkanen, Jenni
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Helsinki, Finland.
    Olenius, Tinja
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Kulmala, Markku
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Exploring the potential of nano-Kohler theory to describe the growth of atmospheric molecular clusters by organic vapors using cluster kinetics simulations2018In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, no 18, p. 13733-13754Article in journal (Refereed)
    Abstract [en]

    Atmospheric new particle formation (NPF) occurs by the formation of nanometer-sized molecular clusters and their subsequent growth to larger particles. NPF involving sulfuric acid, bases and oxidized organic compounds is an important source of atmospheric aerosol particles. One of the mechanisms suggested to depict this process is nano-Kohler theory, which describes the activation of inorganic molecular clusters to growth by a soluble organic vapor. In this work, we studied the capability of nano-Kohler theory to describe the initial growth of atmospheric molecular clusters by simulating the dynamics of a cluster population in the presence of a sulfuric acid-base mixture and an organic compound. We observed nano-Kohler-type activation in our simulations when the saturation ratio of the organic vapor and the ratio between organic and inorganic vapor concentrations were in a suitable range. However, nano-Kohler theory was unable to predict the exact size at which the activation occurred in the simulations. In some conditions, apparent cluster growth rate (GR) started to increase close to the activation size determined from the simulations. Nevertheless, because the behavior of GR is also affected by other dynamic processes, GR alone cannot be used to deduce the cluster growth mechanism.

  • 321. Kontkanen, Jenni
    et al.
    Olenius, Tinja
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lehtipalo, Katrianne
    Vehkamäki, Hanna
    Kulmala, Markku
    Lehtinen, Kari E. J.
    Growth of atmospheric clusters involving cluster-cluster collisions: comparison of different growth rate methods2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 9, p. 5545-5560Article in journal (Refereed)
    Abstract [en]

    We simulated the time evolution of atmospheric cluster concentrations in a one-component system where not only do clusters grow by condensation of monomers, but cluster-cluster collisions also significantly contribute to the growth of the clusters. Our aim was to investigate the consistency of the growth rates of sub-3aEuro-nm clusters determined with different methods and the validity of the common approach to use them to estimate particle formation rates. We compared the growth rate corresponding to particle fluxes (FGR), the growth rate derived from the appearance times of clusters (AGR), and the growth rate calculated based on irreversible vapor condensation (CGR). We found that the relation between the different growth rates depends strongly on the external conditions and the properties of the model substance. The difference between the different growth rates was typically highest at the smallest, sub-2aEuro-nm sizes. FGR was generally lower than AGR and CGR; at the smallest sizes the difference was often very large, while at sizes larger than 2aEuro-nm the growth rates were closer to each other. AGR and CGR were in most cases close to each other at all sizes. The difference between the growth rates was generally lower in conditions where cluster concentrations were high, and evaporation and other losses were thus less significant. Furthermore, our results show that the conventional method used to determine particle formation rates from growth rates may give estimates far from the true values. Thus, care must be taken not only in how the growth rate is determined but also in how it is applied.

  • 322. Koponen, Jani
    et al.
    Winkens, Kerstin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Airaksinen, Riikka
    Berger, Urs
    Vestergren, Robin
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karvonen, Anne M.
    Pekkanen, Juha
    Kiviranta, Hannu
    Longitudinal trends of per- and polyfluoroalkyl substances in children’s serumManuscript (preprint) (Other academic)
  • 323. Koponen, Jani
    et al.
    Winkens, Kerstin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Airaksinen, Riikka
    Berger, Urs
    Vestergren, Robin
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karvonen, Anne M.
    Pekkanen, Juha
    Kiviranta, Hannu
    Longitudinal trends of per- and polyfluoroalkyl substances in children's serum2018In: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 121, p. 591-599Article in journal (Refereed)
    Abstract [en]

    Studies suggest negative health impacts from early life exposure to per- and polyfluoroalkyl substances (PFASs). However, information on longitudinal exposure to PFASs during childhood is scarce for background-exposed individuals. This study sought to fill this gap by investigating children's longitudinal exposure trends through measurement of PFAS serum concentrations and calculation of body burdens (mu g, total in body). Blood of 54 Finnish children was sampled 2005-2015 and analyzed for 20 PFASs at 1, 6 and 10.5 years of age. The body burden was calculated by multiplying the serum concentration by the volume of distribution and the bodyweight for each individual. Associations between serum concentrations or body burdens and parameters, such as sex, breastfeeding duration, body mass index as well as indoor dust and air PFAS concentrations, were evaluated. Serum concentrations of perfluorooctane sulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) decreased significantly (p < 0.001) with age. In contrast to serum concentrations, body burdens stayed unchanged or even increased significantly (p < 0.05), except for PFOA in female children. Breastfeeding duration was positively correlated (p < 0.001) with serum concentrations of PFHxS, PFOS, PFOA and PFNA at 1 year of age. Some associations were found at 10.5 years with sex and indoor PFAS concentrations. Observations of longitudinal decreasing trends of serum concentrations can be misleading for understanding exposure levels from external media during childhood, as the serum concentration is influenced by parallel temporal changes and growth dilution. Body burdens account for growth dilution and thus better reflect differences in early-life to adolescence exposure than serum concentrations.

  • 324. Korek, Michal
    et al.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Environment and Health Administration, Sweden.
    Svensson, Nina
    Lind, Tomas
    Beelen, Rob
    Hoek, Gerard
    Pershagen, Goran
    Bellander, Tom
    Can dispersion modeling of air pollution be improved by land-use regression? An example from Stockholm, Sweden2017In: Journal of Exposure Science and Environmental Epidemiology, ISSN 1559-0631, E-ISSN 1559-064X, Vol. 27, no 6, p. 575-581Article in journal (Refereed)
    Abstract [en]

    Both dispersion modeling (DM) and land-use regression modeling (LUR) are often used for assessment of long-term air pollution exposure in epidemiological studies, but seldom in combination. We developed a hybrid DM-LUR model using 93 biweekly observations of NOx at 31 sites in greater Stockholm (Sweden). The DM was based on spatially resolved topographic, physiographic and emission data, and hourly meteorological data from a diagnostic wind model. Other data were from land use, meteorology and routine monitoring of NOx. We built a linear regression model for NOx, using a stepwise forward selection of covariates. The resulting model predicted observed NOx (R-2 = 0.89) better than the DM without covariates (R-2 = 0.68, P-interaction < 0.001) and with minimal apparent bias. The model included (in descending order of importance) DM, traffic intensity on the nearest street, population (number of inhabitants) within 100 m radius, global radiation (direct sunlight plus diffuse or scattered light) and urban contribution to NOx levels (routine urban NOx, less routine rural NOx). Our results indicate that there is a potential for improving estimates of air pollutant concentrations based on DM, by incorporating further spatial characteristics of the immediate surroundings, possibly accounting for imperfections in the emission data.

  • 325. Kosmach, D. A.
    et al.
    Sergienko, V. I.
    Dudarev, O. V.
    Kurilenko, A. V.
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Semiletov, I. P.
    Shakhova, N. E.
    Methane in the surface waters of Northern Eurasian marginal seas2015In: Doklady. Chemistry, ISSN 0012-5008, E-ISSN 1608-3113, Vol. 465, p. 281-285Article in journal (Refereed)
    Abstract [en]

    More than 12 000 measurements of the dissolved methane (CH4) concentrations in the surface waters of Northern Eurasian marginal seas (Barents, Kara, Laptev, Chukchi, and Bering Seas, Sea of Okhotsk, and Sea of Japan) during two marine expeditions (September-October 2011 and 2012) show that all seas are CH4 source to the atmosphere, but the Laptev and East Siberian seas demonstrate the strongest signal.

  • 326. Krecl, Patricia
    et al.
    Johansson, Christer
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Stockholm Environment and Health Administration, Sweden.
    Créso Targino, Admir
    Ström, Johan
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Burman, Lars
    Trends in black carbon and size-resolved particle number concentrations and vehicle emission factors under real-world conditions2017In: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 165, p. 155-168Article in journal (Refereed)
    Abstract [en]

    Kerbside concentrations of NOx, black carbon (BC), total number of particles (diameter > 4 nm) and number size distribution (28-410 nm) were measured at a busy street canyon in Stockholm in 2006 and 2013. Over this period, there was an important change in the vehicle fleet due to a strong dieselisation process of light-duty vehicles and technological improvement of vehicle engines. This study assesses the impact of these changes on ambient concentrations and particle emission factors (EF). EF were calculated by using a novel approach which combines the NOx tracer method with positive matrix factorisation (PMF) applied to particle number size distributions. NOx concentrations remained rather constant between these two years, whereas a large decrease in particle concentrations was observed, being on average 60% for BC, 50% for total particle number, and 53% for particles in the range 28-100 nm. The PMF analysis yielded three factors that were identified as contributions from gasoline vehicles, diesel fleet, and urban background. This separation allowed the calculation of the average vehicle EF for each particle metric per fuel type. In general, gasoline EF were lower than diesel EF, and EF for 2013 were lower than the ones derived for 2006. The EFBC decreased 77% for both gasoline and diesel fleets, whereas the particle number EF reduction was higher for the gasoline (79%) than for the diesel (37%) fleet. Our EF are consistent with results from other on-road studies, which reinforces that the proposed methodology is suitable for EF determination and to assess the effectiveness of policies implemented to reduce vehicle exhaust emissions. However, our EF are much higher than EF simulated with traffic emission models (HBEFA and COPERT) that are based on dynamometer measurements, except for EFBC for diesel vehicles. This finding suggests that the EF from the two leading models in Europe should be revised for BC (gasoline vehicles) and particle number (all vehicles), since they are used to compile national inventories for the road transportation sector and also to assess their associated health effects. Using the calculated kerbside EF, we estimated that the traffic emissions were lower in 2013 compared to 2006 with a 61% reduction for BC (due to decreases in both gasoline and diesel emissions), and 34-45% for particle number (reduction only in gasoline emissions). Limitations of the application of these EF to other studies are also discussed.

  • 327. Krieger, Ulrich K.
    et al.
    Siegrist, Franziska
    Marcolli, Claudia
    Emanuelsson, Eva U.
    Gøbel, Freya M.
    Bilde, Merete
    Marsh, Aleksandra
    Reid, Jonathan P.
    Huisman, Andrew J.
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hyttinen, Noora
    Myllys, Nanna
    Kurtén, Theo
    Bannan, Thomas
    Percival, Carl J.
    Topping, David
    A reference data set for validating vapor pressure measurement techniques: homologous series of polyethylene glycols2018In: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 11, no 1, p. 49-63Article in journal (Refereed)
    Abstract [en]

    To predict atmospheric partitioning of organic compounds between gas and aerosol particle phase based on explicit models for gas phase chemistry, saturation vapor pressures of the compounds need to be estimated. Estimation methods based on functional group contributions require training sets of compounds with well-established saturation vapor pressures. However, vapor pressures of semivolatile and low-volatility organic molecules at atmospheric temperatures reported in the literature often differ by several orders of magnitude between measurement techniques. These discrepancies exceed the stated uncertainty of each technique which is generally reported to be smaller than a factor of 2. At present, there is no general reference technique for measuring saturation vapor pressures of atmospherically relevant compounds with low vapor pressures at atmospheric temperatures. To address this problem, we measured vapor pressures with different techniques over a wide temperature range for intercomparison and to establish a reliable training set. We determined saturation vapor pressures for the homologous series of polyethylene glycols (H-(O-CH2-CH2)(n)-OH) for n = 3 to n = 8 ranging in vapor pressure at 298 K from 10(-7) to 5 x 10(-2) Pa and compare them with quantum chemistry calculations. Such a homologous series provides a reference set that covers several orders of magnitude in saturation vapor pressure, allowing a critical assessment of the lower limits of detection of vapor pressures for the different techniques as well as permitting the identification of potential sources of systematic error. Also, internal consistency within the series allows outlying data to be rejected more easily. Most of the measured vapor pressures agreed within the stated uncertainty range. Deviations mostly occurred for vapor pressure values approaching the lower detection limit of a technique. The good agreement between the measurement techniques (some of which are sensitive to the mass accommodation coefficient and some not) suggests that the mass accommodation coefficients of the studied compounds are close to unity. The quantum chemistry calculations were about 1 order of magnitude higher than the measurements. We find that extrapolation of vapor pressures from elevated to atmospheric temperatures is permissible over a range of about 100 K for these compounds, suggesting that measurements should be performed best at temperatures yielding the highest-accuracy data, allowing subsequent extrapolation to atmospheric temperatures.

  • 328. Krogseth, Ingjerd S.
    et al.
    Undeman, Emma
    Stockholm University, Faculty of Science, Stockholm University Baltic Sea Centre. Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Evenset, Anita
    Christensen, Guttorm N.
    Whelan, Mick J.
    Breivik, Knut
    Warner, Nicholas A.
    Elucidating the Behavior of Cyclic Volatile Methylsiloxanes in a Subarctic Freshwater Food Web: A Modeled and Measured Approach2017In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, no 21, p. 12489-12497Article in journal (Refereed)
    Abstract [en]

    Cyclic volatile methylsiloxanes (cVMS) are used in personal care products and emitted to aquatic environments through wastewater effluents, and their bioaccumulation potential is debated. Here, a new bentho-pelagic version of the ACC-HUMAN model was evaluated for polychlorinated biphenyls (PCBs) and applied to cVMS in combination with measurements to explore their bioaccumulation behavior in a subarctic lake. Predictions agreed better with measured PCB concentrations in Arctic char (Salvelinus alpinus) and brown trout (Salmo trutta) when the benthic link was included than in the pelagic-only model. Measured concentrations of decamethylcyclopentasiloxane (D5) were 60 +/- 1.2 (Chironomidae larvae), 107 +/- 4.5 (pea clams Pisidium sp.), 131 +/- 105 (three-spined sticklebacks: Gasterosteus aculeatus), 41 +/- 38 (char), and 9.9 +/- 5.9 (trout) ng g(-1) wet weight. Concentrations were lower for octamethylcyclotetrasiloxane (D4) and dodecamethylcyclohexasiloxane (D6), and none of the cVMS displayed trophic magnification. Predicted cVMS concentrations were lower than measured in benthos, but agreed well with measurements in fish. cVMS removal through ventilation was an important predicted loss mechanism for the benthic-feeding fish. Predictions were highly sensitive to the partition coefficient between organic carbon and water (K-OC) and its temperature dependence, as this controlled bioavailability for benthos (the main source of cVMS for fish).

  • 329. Kulmala, M.
    et al.
    Lappalainen, H. K.
    Petaja, T.
    Kurten, T.
    Kerminen, V. -M.
    Viisanen, Y.
    Hari, P.
    Sorvari, S.
    Back, J.
    Bondur, V.
    Kasimov, N.
    Kotlyakov, V.
    Matvienko, G.
    Baklanov, A.
    Guo, H. D.
    Ding, A.
    Hansson, Hans-Christen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Zilitinkevich, S.
    Introduction: The Pan-Eurasian Experiment (PEEX) - multidisciplinary, multiscale and multicomponent research and capacity-building initiative2015In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, no 22, p. 13085-13096Article in journal (Refereed)
    Abstract [en]

    The Pan-Eurasian Experiment (PEEX) is a multidisciplinary, multiscale and multicomponent research, research infrastructure and capacity-building program. PEEX has originated from a bottom-up approach by the science communities and is aiming at resolving the major uncertainties in Earth system science and global sustainability issues concerning the Arctic and boreal pan-Eurasian regions, as well as China. The vision of PEEX is to solve interlinked, global grand challenges influencing human well-being and societies in northern Eurasia and China. Such challenges include climate change; air quality; biodiversity loss; urbanization; chemicalization; food and freshwater availability; energy production; and use of natural resources by mining, industry, energy production and transport sectors. Our approach is integrative and supra-disciplinary, recognizing the important role of the Arctic and boreal ecosystems in the Earth system. The PEEX vision includes establishing and maintaining long-term, coherent and coordinated research activities as well as continuous, comprehensive research and educational infrastructure and related capacity-building across the PEEX domain. In this paper we present the PEEX structure and summarize its motivation, objectives and future outlook.

  • 330. Kunzelmann, Marco
    et al.
    Winter, Martin
    Åberg, Magnus
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hellenäs, Karl-Erik
    Rosén, Johan
    Non-targeted analysis of unexpected food contaminants using LC-HRMS2018In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 410, no 22, p. 5593-5602Article in journal (Refereed)
    Abstract [en]

    A non-target analysis method for unexpected contaminants in food is described. Many current methods referred to as non-target are capable of detecting hundreds or even thousands of contaminants. However, they will typically still miss all other possible contaminants. Instead, a metabolomics approach might be used to obtain true non-target analysis. In the present work, such a method was optimized for improved detection capability at low concentrations. The method was evaluated using 19 chemically diverse model compounds spiked into milk samples to mimic unknown contamination. Other milk samples were used as reference samples. All samples were analyzed with UHPLC-TOF-MS (ultra-high-performance liquid chromatography time-of-flight mass spectrometry), using reversed-phase chromatography and electrospray ionization in positive mode. Data evaluation was performed by the software TracMass 2. No target lists of specific compounds were used to search for the contaminants. Instead, the software was used to sort out all features only occurring in the spiked sample data, i.e., the workflow resembled a metabolomics approach. Procedures for chemical identification of peaks were outside the scope of the study. Method, study design, and settings in the software were optimized to minimize manual evaluation and faulty or irrelevant hits and to maximize hit rate of the spiked compounds. A practical detection limit was established at 25 mu g/kg. At this concentration, most compounds (17 out of 19) were detected as intact precursor ions, as fragments or as adducts. Only 2 irrelevant hits, probably natural compounds, were obtained. Limitations and possible practical use of the approach are discussed.

  • 331.
    Kylin, Henrik
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Linköping University, Sweden; Norwegian Institute for Air Research, Fram Centre, Norway.
    Hammar, Johan
    Mowrer, Jacques
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bouwman, Henk
    Edelstam, Carl
    Olsson, Mats
    Jensen, Sören
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Persistent organic pollutants in biota samples collected during the Ymer-80 expedition to the Arctic2015In: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 34, article id 21129Article in journal (Refereed)
    Abstract [en]

    During the 1980 expedition to the Arctic with the icebreaker Ymer, a number of vertebrate species were sampled for determination of persistent organic pollutants. Samples of Arctic char (Salvelinus alpinus, n = 34), glaucous gull (Larus hyperboreus, n = 8), common eider (Somateria mollissima, n = 10), Brunnich's guillemot (Uria lomvia, n = 9), ringed seal (Pusa hispida, n = 2) and polar bear (Ursus maritimus, n = 2) were collected. With the exception of Brunnich's guillemot, there was a marked contamination difference of birds from western as compared to eastern/northern Svalbard. Samples in the west contained a larger number of polychlorinated biphenyl (PCB) congeners and also polychlorinated terphenyls, indicating local sources. Brunnich's guillemots had similar pollutant concentrations in the west and east/north; possibly younger birds were sampled in the west. In Arctic char, pollutant profiles from lake Linnevatn (n = 5), the lake closest to the main economic activities in Svalbard, were similar to profiles in Arctic char from the Shetland Islands (n = 5), but differed from lakes to the north and east in Svalbard (n = 30). Arctic char samples had higher concentrations of hexachlorocyclohexanes (HCHs) than the marine species of birds and mammals, possibly due to accumulation via snowmelt. Compared to the Baltic Sea, comparable species collected in Svalbard had lower concentrations of PCB and dichlorodiphenyltrichloroethane (DDT), but similar concentrations indicating long-range transport of hexachlorobenzene, HCHs and cyclodiene pesticides. In samples collected in Svalbard in 1971, the concentrations of PCB and DDT in Brunnich's guillemot (n = 7), glaucous gull (n = 2) and polar bear (n = 2) were similar to the concentrations found in 1980.

  • 332. Kylin, Henrik
    et al.
    Svensson, Teresia
    Jensen, Sören
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Strachan, William M. J.
    Franich, Robert
    Bouwman, Hindrik
    The trans-continental distributions of pentachlorophenol and pentachloroanisole in pine needles indicate separate origins2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 229, p. 688-695Article in journal (Refereed)
    Abstract [en]

    The production and use of pentachlorophenol (PCP) was recently prohibited/restricted by the Stockholm Convention on persistent organic pollutants (POPs), but environmental data are few and of varying quality. We here present the first extensive dataset of the continent-wide (Eurasia and Canada) occurrence of PCP and its methylation product pentachloroanisole (PCA) in the environment, specifically in pine needles. The highest concentrations of PCP were found close to expected point sources, while PCA chiefly shows a northern and/or coastal distribution not correlating with PCP distribution. Although long-range transport and environmental methylation of PCP or formation from other precursors cannot be excluded, the distribution patterns suggest that such processes may not be the only source of PCA to remote regions and unknown sources should be sought. We suggest that natural sources, e.g., chlorination of organic matter in Boreal forest soils enhanced by chloride deposition from marine sources, should be investigated as a possible partial explanation of the observed distributions. The results show that neither PCA nor total PCP (Sigma PCP = PCP + PCA) should be used to approximate the concentrations of PCP; PCP and PCA must be determined and quantified separately to understand their occurrence and fate in the environment. The background work shows that the accumulation of airborne POPs in plants is a complex process. The variations in life cycles and physiological adaptations have to be taken into account when using plants to evaluate the concentrations of POPs in remote areas.

  • 333.
    Lade, Steven J.
    et al.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. The Australian National University, Australia.
    Donges, Jonathan F.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Fetzer, Ingo
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Anderies, John M.
    Beer, Christian
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cornell, Sarah E.
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Gasser, Thomas
    Norberg, Jon
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Richardson, Katherine
    Rockström, Johan
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Steffen, Will
    Stockholm University, Faculty of Science, Stockholm Resilience Centre.
    Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing2018In: Earth System Dynamics, ISSN 2190-4979, E-ISSN 2190-4987, Vol. 9, no 2, p. 507-523Article in journal (Refereed)
    Abstract [en]

    Changes to climate-carbon cycle feedbacks may significantly affect the Earth system's response to greenhouse gas emissions. These feedbacks are usually analysed from numerical output of complex and arguably opaque Earth system models. Here, we construct a stylised global climate-carbon cycle model, test its output against comprehensive Earth system models, and investigate the strengths of its climate-carbon cycle feedbacks analytically. The analytical expressions we obtain aid understanding of carbon cycle feedbacks and the operation of the carbon cycle. Specific results include that different feedback formalisms measure fundamentally the same climate-carbon cycle processes; temperature dependence of the solubility pump, biological pump, and CO2 solubility all contribute approximately equally to the ocean climate-carbon feedback; and concentration-carbon feedbacks may be more sensitive to future climate change than climate-carbon feedbacks. Simple models such as that developed here also provide workbenches for simple but mechanistically based explorations of Earth system processes, such as interactions and feedbacks between the planetary boundaries, that are currently too uncertain to be included in comprehensive Earth system models.

  • 334.
    Lagerstrom, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lindgren, J. Fredrik
    Holmqvist, Albin
    Dahlström, Mia
    Ytreberg, Erik
    In situ release rates of Cu and Zn from commercial antifouling paints at different salinities2018In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 127, p. 289-296Article in journal (Refereed)
    Abstract [en]

    Antifouling paints are environmentally risk assessed based on their biocidal release rates to the water phase. In situ release rates of copper (Cu) and zinc (Zn) were derived for five commercial paints in two recreational marinas with different salinities (5 and 14 PSU) using an X-Ray Fluorescence spectrometer (XRF). Salinity was found to significantly affect the Cu release, with twice the amount of Cu released at the higher salinity, while its influence on the Zn release was paint-specific. Site-specific release rates for water bodies with salinity gradients, e.g. the Baltic Sea, are therefore necessary for more realistic risk assessments of antifouling paints. Furthermore, the in situ release rates were up to 8 times higher than those generated using standardized laboratory or calculation methods. The environmental risk assessment repeated with the field release rates concludes that it is questionable whether the studied products should be allowed on the Swedish market.

  • 335.
    Lagerström, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Norling, Matz
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Eklund, Britta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Metal contamination at recreational boatyards linked to the use of antifouling paints-investigation of soil and sediment with a field portable XRF2016In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 23, no 10, p. 10146-10157Article in journal (Refereed)
    Abstract [en]

    The application of a field portable X-ray fluorescence spectrometer (FPXRF) to measure Cu, Zn, and Pb in soil and sediments at recreational boatyards by Lake Malaren in Sweden was investigated. Confirmatory chemical analysis on freeze-dried samples shows that, ex situ, the FPXRF produces definitive level data for Cu and Zn and quantitative screening data for Pb, according to USEPA criteria for data quality. Good agreement was also found between the ex situ measurements and the in situ screening. At each of the two studied boatyards, >40 in situ soil measurements were carried out. Statistical differences in soil concentration based on land use were consequently found: the areas used for boat storage and maintenance were significantly higher in Cu and Zn than the areas used for car parking and transportation. The metal pollution in the boat storage areas is therefore shown to be directly linked to hull maintenance activities during which metal-containing antifouling paint particles are shed, end up on the ground, and consequently pollute the soil. In the boat storage areas, the Cu and Zn concentrations often exceeded the national guideline values for soil. In this study, they were also shown to increase with increasing age of the boatyard operation. Pb soil concentrations were only elevated at a few measurement points, reflecting the phasing out of Pb compounds from antifouling products over the past 2 decades. In the surface sediments, concentrations of Cu and Zn were 2-3 times higher compared to deeper levels. No decrease in metal concentration with time was found in the sediments, indicating that boat owners are not complying with the ban of biocide-containing paints in freshwater introduced over 20 years ago.

  • 336.
    Lagerström, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Strand, Jakob
    Eklund, Britta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ytreberg, Erik
    Total tin and organotin speciation in historic layers of antifouling paint on leisure boat hulls2017In: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 220, p. 1333-1341Article in journal (Refereed)
    Abstract [en]

    Despite their ban on small vessels in 1989 in the EU, organotin compounds (OTCs) are still being released into the environment due to their presence in historic paint layers on leisure boats. 23 paint samples scraped from recreational boats from three countries around the Baltic Sea were analyzed for total tin (Sn) and OTCs. Two antifouling paint products were also subjected to the same analyses. A new method for the detection of Sn in paint flake samples was developed and found to yield more accurate results compared to four different acid digestion methods. A new method was also developed for the extraction of OTCs from ground paint flakes. This endeavor revealed that existing methods for organotin analysis of sediment may not have full recoveries of OTCs if paint flakes are present in the sample. The hull paint samples had Sn concentrations ranging from 25 to 18,000 mg/kg paint and results showed that tributyltin (TBT) was detected in all samples with concentrations as high as 4.7 g (as Sn)/kg paint. TBT was however not always the major OTC. Triphenyltin (TPhT) was abundant in many samples, especially in those originating from Finland. Several other compounds such as monobutyltin (MBT), dibutyltin (DBT), tetrabutyltin (TeBT), monophenyltin (MPhT) and diphenyltin (DPhT) were also detected. These could be the result of degradation occurring on the hull or of impurities in the paint products as they were also identified in the two analyzed paint products. A linear correlation (r(2) = 0.934) was found between the total tin content and the sum of all detected OTCs. The detection of tin can therefore be used to indicate the presence of OTCs on leisure boats. (C) 2016 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license.

  • 337. Lagerström, Maria
    et al.
    Yngsell, Daniel
    Eklund, Britta
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Ytreberg, Erik
    Identification of commercial and recreational vessels coated with banned organotin paint through screening of tin by portable XRF2019In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 362, p. 107-114Article in journal (Refereed)
    Abstract [en]

    The most effective biocide used historically in antifouling paints is tributyltin (TBT). However, due to its extreme toxicity to non-target organisms and its persistence in the environment, the use of TBT and other organotin compounds (OTCs) was restricted in EU on leisure boats and ships in 1989 and 2003, respectively. Nevertheless, studies worldwide still report TBT to be released from both ships and leisure boats. Here, we present a new application for a field portable X-ray fluorescence spectrometer (XRF) used for screening for organotin paint through measurements of tin (Sn) on leisure boats and ships. Measurements on ships built after the restrictions showed concentrations of up to 68 mu g Sn/cm(2), likely due to impurities of inorganic Sn, as shown through chemical analysis of 21 organotin-free paints. A threshold value of 100 mu g Sn/cm(2) is suggested, where exceedance indicates presence of OTCs. Screening with the XRF method showed 10% of the commercial vessels (n = 30) and 23-29% of leisure boats (n = 693, investigated in this and in a previous study) to hold concentrations exceeding 100 mu g Sn/cm(2). The XRF technique presented here provides a useful tool for quick screening and identification of vessels holding banned organotin paint.

  • 338. Land, Magnus
    et al.
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Bignert, Anders
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Herzke, Dorte
    Johansson, Jana H.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Martin, Jonathan W.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Alberta, Canada.
    What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review2018In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 7, no 1, article id UNSP 4Article, review/survey (Refereed)
    Abstract [en]

    Background: There is a concern that continued emissions of man-made per-and polyfluoroalkyl substances (PFASs) may cause environmental and human health effects. Now widespread in human populations and in the environment, several PFASs are also present in remote regions of the world, but the environmental transport and fate of PFASs are not well understood. Phasing out the manufacture of some types of PFASs started in 2000 and further regulatory and voluntary actions have followed. The objective of this review is to understand the effects of these actions on global scale PFAS concentrations. Methods: Searches for primary research studies reporting on temporal variations of PFAS concentrations were performed in bibliographic databases, on the internet, through stakeholder contacts and in review bibliographies. No time, document type, language or geographical constraints were applied in the searches. Relevant subjects included human and environmental samples. Two authors screened all retrieved articles. Dual screening of 10% of the articles was performed at title/abstract and full-text levels by all authors. Kappa tests were used to test consistency. Relevant articles were critically appraised by four reviewers, with double checking of 20% of the articles by a second reviewer. Meta-analysis of included temporal trends was considered but judged to not be appropriate. The trends were therefore discussed in a narrative synthesis. Results: Available evidence suggests that human concentrations of perfluorooctane sulfonate (PFOS), perfluorodecane sulfonate (PFDS), and perfluorooctanoic acid (PFOA) generally are declining, while previously increasing concentrations of perfluorohexane sulfonate (PFHxS) have begun to level off. Rapid declines for PFOS-precursors (e.g. perfluorooctane sulfonamide, FOSA) have also been consistently observed in human studies. In contrast, limited data indicate that human concentrations of PFOS and PFOA are increasing in China where the production of these substances has increased. Human concentrations of longer-chained perfluoroalkyl carboxylic acids (PFCAs) with 9-14 carbon atoms are generally increasing or show insignificant trends with too low power to detect a trend. For abiotic and biological environmental samples there are no clear patterns of declining trends. Most substances show mixed results, and a majority of the trends are insignificant with low power to detect a trend. Conclusions: For electrochemically derived PFASs, including PFOS and PFOA, most human studies in North America and Europe show consistent statistically significant declines. This contrasts with findings in wildlife and in abiotic environmental samples, suggesting that declining PFOS, PFOS-precursor and PFOA concentrations in humans likely resulted from removal of certain PFASs from commercial products including paper and board used in food packaging. Increasing concentrations of long-chain PFCAs in most matrices, and in most regions, is likely due to increased use of alternative PFASs. Continued temporal trend monitoring in the environment with well-designed studies with high statistical power are necessary to evaluate the effectiveness of past and continuing regulatory mitigation measures. For humans, more temporal trend studies are needed in regions where manufacturing is most intense, as the one human study available in China is much different than in North America or Europe.

  • 339. Land, Magnus
    et al.
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Cousins, Ian T.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Herzke, Dorte
    Johansson, Jana
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Martin, Jonathan W.
    What is the effect of phasing out long-chain per- and polyfluoroalkyl substances on the concentrations of perfluoroalkyl acids and their precursors in the environment? A systematic review protocol2015In: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 4, article id 3Article in journal (Refereed)
    Abstract [en]

    Background

    There is a growing concern in Sweden and elsewhere that continued emissions of per- and polyfluoroalkyl substances (PFASs) may cause environmental as well as human health effects. PFASs are a broad class of man-made substances that have been produced and used in both commercial products and industrial processes for more than 60 years. Although the production and use of some PFASs has been phased-out in some parts of the world, it is not known what effect these actions to date have had on PFAS concentrations in the environment. Owing to the wide diversity of PFASs, it is difficult to generalize their properties, environmental fate and production histories. However, the strength and stability of the C-F bond renders the perfluoroalkyl moieties resistant to heat and environmental degradation. Several PFASs are now occurring even in very remote areas in large parts of the world, but the environmental transport and fate of substances within this group is not well understood. A systematic review may be able to determine whether the concentrations of these substances in different environments are changing in any particular direction with time, and whether the phase-outs have had any effects on the concentration trends.

    Methods

    Searches for primary research studies reporting on temporal variations of PFAS concentrations in the environment will be performed in the scientific literature as well as in other reports. Relevant samples include both abiotic and biological samples including humans. No particular time, document type, language or geographical constraints will be applied. Two authors will screen all retrieved articles. Double screening of about 10% of the articles will be performed by all authors at both title/abstract and full-text levels. Kappa tests will be used to test if the screening is consistent. Relevant articles will be critically appraised by four authors (double checking of 25% of the articles). Quality assessment will focus on selection bias, dating of samples, sample integrity and analytical procedures. Data synthesis will be based on statistical analysis of temporal concentration trends.

  • 340. Landhausser, Simon M.
    et al.
    Chow, Pak S.
    Dickman, L. Turin
    Furze, Morgan E.
    Kuhlman, Iris
    Schmid, Sandra
    Wiesenbauer, Julia
    Wild, Birgit
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. University of Gothenburg, Sweden.
    Gleixner, Gerd
    Hartmann, Henrik
    Hoch, Guenter
    McDowell, Nate G.
    Richardson, Andrew D.
    Richter, Andreas
    Adams, Henry D.
    Standardized protocols and procedures can precisely and accurately quantify non-structural carbohydrates2018In: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 38, no 12, p. 1764-1778Article in journal (Refereed)
    Abstract [en]

    Non-structural carbohydrates (NSCs), the stored products of photosynthesis, building blocks for growth and fuel for respiration, are central to plant metabolism, but their measurement is challenging. Differences in methods and procedures among laboratories can cause results to vary widely, limiting our ability to integrate and generalize patterns in plant carbon balance among studies. A recent assessment found that NSC concentrations measured for a common set of samples can vary by an order of magnitude, but sources for this variability were unclear. We measured a common set of nine plant material types, and two synthetic samples with known NSC concentrations, using a common protocol for sugar extraction and starch digestion, and three different sugar quantification methods (ion chromatography, enzyme, acid) in six laboratories. We also tested how sample handling, extraction solvent and centralizing parts of the procedure in one laboratory affected results. Non-structural carbohydrate concentrations measured for synthetic samples were within about 11.5% of known values for all three methods. However, differences among quantification methods were the largest source of variation in NSC measurements for natural plant samples because the three methods quantify different NSCs. The enzyme method quantified only glucose, fructose and sucrose, with ion chromatography we additionally quantified galactose, while the acid method quantified a large range of mono- and oligosaccharides. For some natural samples, sugars quantified with the acid method were two to five times higher than with other methods, demonstrating that trees allocate carbon to a range of sugar molecules. Sample handling had little effect on measurements, while ethanol sugar extraction improved accuracy over water extraction. Our results demonstrate that reasonable accuracy of NSC measurements can be achieved when different methods are used, as long as protocols are robust and standardized. Thus, we provide detailed protocols for the extraction, digestion and quantification of NSCs in plant samples, which should improve the comparability of NSC measurements among laboratories.

  • 341. Lappalainen, Hanna K.
    et al.
    Kerminen, Veli-Matti
    Petaja, Tuukka
    Kurten, Theo
    Baklanov, Aleksander
    Shvidenko, Anatoly
    Back, Jaana
    Vihma, Timo
    Alekseychik, Pavel
    Andreae, Meinrat O.
    Arnold, Stephen R.
    Arshinov, Mikhail
    Asmi, Eija
    Belan, Boris
    Bobylev, Leonid
    Chalov, Sergey
    Cheng, Yafang
    Chubarova, Natalia
    de Leeuw, Gerrit
    Ding, Aijun
    Dobrolyubov, Sergey
    Dubtsov, Sergei
    Dyukarev, Egor
    Elansky, Nikolai
    Eleftheriadis, Kostas
    Esau, Igor
    Filatov, Nikolay
    Flint, Mikhail
    Fu, Congbin
    Glezer, Olga
    Gliko, Aleksander
    Heimann, Martin
    Holtslag, Albert A. M.
    Horrak, Urmas
    Janhunen, Juha
    Juhola, Sirkku
    Jarvi, Leena
    Jarvinen, Heikki
    Kanukhina, Anna
    Konstantinov, Pavel
    Kotlyakov, Vladimir
    Kieloaho, Antti-Jussi
    Komarov, Alexander S.
    Kujansuu, Joni
    Kukkonen, Ilmo
    Duplissy, Ella-Maria
    Laaksonen, Ari
    Laurila, Tuomas
    Lihavainen, Heikki
    Lisitzin, Alexander
    Mahura, Alexsander
    Makshtas, Alexander
    Mareev, Evgeny
    Mazon, Stephany
    Matishov, Dmitry
    Melnikov, Vladimir
    Mikhailov, Eugene
    Moisseev, Dmitri
    Nigmatulin, Robert
    Noe, Steffen M.
    Ojala, Anne
    Pihlatie, Mari
    Popovicheva, Olga
    Pumpanen, Jukka
    Regerand, Tatjana
    Repina, Irina
    Shcherbinin, Aleksei
    Shevchenko, Vladimir
    Sipila, Mikko
    Skorokhod, Andrey
    Spracklen, Dominick V.
    Su, Hang
    Subetto, Dmitry A.
    Sun, Junying
    Terzhevik, Arkady Y.
    Timofeyev, Yuri
    Troitskaya, Yuliya
    Tynkkynen, Veli-Pekka
    Kharuk, Viacheslav I.
    Zaytseva, Nina
    Zhang, Jiahua
    Viisanen, Yrjo
    Vesala, Timo
    Hari, Pertti
    Hansson, Hans Christen
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Matvienko, Gennady G.
    Kasimov, Nikolai S.
    Guo, Huadong
    Bondur, Valery
    Zilitinkevich, Sergej
    Kulmala, Markku
    Pan-Eurasian Experiment (PEEX): towards a holistic understanding of the feedbacks and interactions in the land-atmosphere-ocean-society continuum in the northern Eurasian region2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 22, p. 14421-14461Article in journal (Refereed)
    Abstract [en]

    The northern Eurasian regions and Arctic Ocean will very likely undergo substantial changes during the next decades. The Arctic-boreal natural environments play a crucial role in the global climate via albedo change, carbon sources and sinks as well as atmospheric aerosol production from biogenic volatile organic compounds. Furthermore, it is expected that global trade activities, demographic movement, and use of natural resources will be increasing in the Arctic regions. There is a need for a novel research approach, which not only identifies and tackles the relevant multi-disciplinary research questions, but also is able to make a holistic system analysis of the expected feedbacks. In this paper, we introduce the research agenda of the Pan-Eurasian Experiment (PEEX), a multi-scale, multi-disciplinary and international program started in 2012 (https://www.atm.helsinki.fi/peex/). PEEX sets a research approach by which large-scale research topics are investigated from a system perspective and which aims to fill the key gaps in our understanding of the feedbacks and interactions between the land-atmosphereaquatic-society continuum in the northern Eurasian region. We introduce here the state of the art for the key topics in the PEEX research agenda and present the future prospects of the research, which we see relevant in this context.

  • 342. Larsson, Kristin
    et al.
    de Wit, Cynthia A.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sellström, Ulla
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Sahlström, Leena
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lindh, Christian H.
    Berglund, Marika
    Brominated Flame Retardants and Organophosphate Esters in Preschool Dust and Children's Hand Wipes2018In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, no 8, p. 4878-4888Article in journal (Refereed)
    Abstract [en]

    Children spend a considerable part of their day in preschool, where they may be exposed to hazardous chemicals in indoor dust. In this study, brominated flame retardants (BFRs) and organophosphate esters (OPEs) were analyzed in preschool dust ( n = 100) and children's hand wipe samples ( n = 100), and diphenyl phosphate (DPHP) was analyzed in urine ( n = 113). Here we assessed children's exposure via dust, identified predictors for chemicals in dust, and studied correlations between different exposure measures. The most abundant BFRs in dust were decabromodiphenyl ether (BDE-209) and decabromodiphenyl ethane (DBDPE) found at median levels of 270 and 110 ng/g dust, respectively. Tris(2-butoxyethyl) phosphate (TBOEP) was the most abundant OPE, found at a median level of 79 000 ng/g dust. For all OPEs and some BFRs, there were significant correlations between the levels in dust and hand wipes. In addition, triphenyl phosphate (TPHP) in preschool dust was significantly correlated with the corresponding metabolite DPHP in children's urine. The levels of pentaBDEs in dust were higher in older preschools compared with newer, whereas levels of DBDPE were higher in newer preschools. Children's estimated intakes of individual BFRs and OPEs via preschool dust were below available health-based reference values. However, there are uncertainties about the potential health effects of some emerging BFRs and OPEs.

  • 343.
    Latvala, Siiri
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Development and comparison of in vitro toxicity methods for nanoparticles: Focus on lung cell exposure2016Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Concerns for the toxic effects of airborne nanoparticles have been raised along with the increasing production of nanostructured materials. However, the health risks of nanoparticle exposure are currently not fully understood. The most commonly used techniques to study nanoparticle toxicity, both in vivo and in vitro, have several limitations. These include for example challenges regarding dosimetry or the lack of similarity of overall exposure conditions and the physico-chemical particle characteristics. Therefore, there is a need for more advanced methods to study the pulmonary toxicity of airborne nanoparticles.

    This thesis presents the use of air-liquid interface (ALI) systems as a possible approach to this challenge. While utilizing the direct deposition of airborne nanoparticles on lung cell cultures, the ALI approach can more realistically mimic the characteristics of the human respiratory tract and the interactions of airborne particles with lung cells. This allows for a better understanding of the health risks posed by inhalation exposure to nanoparticles.

    Two different ALI systems were investigated and their use was compared to submerged exposure methods. One of the ALI exposure systems utilizes electrostatic force in order to make the deposition of charged airborne nanoparticles more efficient, while the other system operates by the diffusion of airborne nanoparticles. ALI and submerged exposure methods were used for investigating the cytotoxicity and genotoxicity of Ni-containing nanoparticles as well as the cytotoxicity and inflammatory potential of CeO2-nanoparticles. While Ag-nanoparticles were used as a test material during the development of the electrostatic ALI system, their cytotoxicity was investigated in ALI exposure. In conclusion, the ALI exposure methods provide more realistic conditions and make the particle dosimetry more controllable.

  • 344.
    Latvala, Siiri
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Lung toxicity of airborne nanoparticles - focus on development of an advanced in vitro exposure system2015Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Inhalation exposure to airborne particles, such as nickel, increases the risk for several respiratory tract diseases. Even though the effects of nickel have been extensively studied, the data for some nickel particle types is currently inconclusive. Certain nickel compounds are established human carcinogens, but for example the carcinogenicity of nickel metal particles has not been confirmed. There are also uncertainties concerning the actual mode of action of nickel. Furthermore, it is unclear, how the physico-chemical particle characteristics affect the carcinogenic potential of nickel. This lack of comprehension is considered to be largely due to the uncertainties in the current toxicological exposure methods both in vivo and in vitro.

    The need for more advanced exposure systems for airborne particles is broadly recognized. Taking into account the distinct characteristics of the human respiratory tract and the ways in which airborne particles move and interact with the pulmonary tissue is essential for better health risk characterizations and assessments of nanoparticles. The vastly expanding nanotechnology industry has amplified this need, as it is likely, that a growing group of workers become exposed to nanoparticles via inhalation for example during the production or conditioning phases of different nanomaterials.

    When the specific cellular-level mechanisms are investigated, the use of in vitro methods is often desirable. Therefore, we have developed a novel in vitro exposure system for toxicological studies of metal-containing nanoparticles. The system comprises human lung cells grown on air liquid interface (ALI), the generation of nanoparticles and their deposition, enhanced by electrostatic force, on the cells. The ALI system resembles more closely the realistic conditions in the human respiratory tract when compared to the more traditional submerged in vitro cell culture exposures.

    Based on our results, we can conclude that studying the relationships between nickel particle characteristics and their toxicological properties is problematic with submerged cell cultures. The ALI exposure system proves, however, promising as a more advanced and realistic exposure approach. We could show an efficient deposition of silver nanoparticles on human alveolar epithelial type II cells (A549) and we did not detect any increased cytotoxicity or DNA damage after clean air exposures. This preliminary study with silver nanoparticles as a test material suggests, that the ALI system can be used for studying the toxicity of airborne metal particles. It remains as our future challenge to use the ALI system for investigating the toxicological mechanisms of nickel, as well as other metal-containing, nanoparticles.

  • 345.
    Latvala, Siiri
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hedberg, Jonas
    Di Bucchianico, Sebastiano
    Möller, Lennart
    Odnevall Wallinder, Inger
    Elihn, Karine
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Karlsson, Hanna L.
    Nickel release, ROS generation and toxicity of Ni and NiO micro- and nanoparticles2016In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, no 7, article id e0159684Article in journal (Refereed)
    Abstract [en]

    Occupational exposure to airborne nickel is associated with an elevated risk for respiratory tract diseases including lung cancer. Therefore, the increased production of Ni-containing nanoparticles necessitates a thorough assessment of their physical, chemical, as well as toxicological properties. The aim of this study was to investigate and compare the characteristics of nickel metal (Ni) and nickel oxide (NiO) particles with a focus on Ni release, reactive oxygen species (ROS) generation, cellular uptake, cytotoxicity and genotoxicity. Four Ni-containing particles of both nano-size (Ni-n and NiO-n) and micron-size (Ni-m1 and Ni-m2) were tested. The released amount of Ni in solution was notably higher in artificial lysosomal fluid (e.g. 80–100 wt% for metallic Ni) than in cell medium after 24h (ca. 1–3 wt% for all particles). Each of the particles was taken up by the cells within 4 h and they remained in the cells to a high extent after 24 h post-incubation. Thus, the high dissolution in ALF appeared not to reflect the particle dissolution in the cells. Ni-m1 showed the most pronounced effect on cell viability after 48 h (alamar blue assay) whereas all particles showed increased cytotoxicity in the highest doses (20–40 μg cm2) when assessed by colony forming efficiency (CFE). Interestingly an increased CFE, suggesting higher proliferation, was observed for all particles in low doses (0.1 or 1 μg cm-2). Ni-m1 and NiO-n were the most potent in causing acellular ROS and DNA damage. However, no intracellular ROS was detected for any of the particles. Taken together, micron-sized Ni (Ni-m1) was more reactive and toxic compared to the nano-sized Ni. Furthermore, this study underlines that the low dose effect in terms of increased proliferation observed for all particles should be further investigated in future studies.

  • 346.
    Latvala, Siiri
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Hedberg, Jonas
    Möller, Lennart
    Odnevall Wallinder, Inger
    Karlsson, Hanna L.
    Elihn, Karine
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Optimization of an air–liquid interface exposure system for assessing toxicity of airborne nanoparticles2016In: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 36, no 10, p. 1294-1301Article in journal (Refereed)
    Abstract [en]

    The use of refined toxicological methods is currently needed for characterizing the risks of airborne nanoparticles (NPs) to human health. To mimic pulmonary exposure, we have developed an air–liquid interface (ALI) exposure system for direct deposition of airborne NPs on to lung cell cultures. Compared to traditional submerged systems, this allows more realistic exposure conditions for characterizing toxicological effects induced by airborne NPs. The purpose of this study was to investigate how the deposition of silver NPs (AgNPs) is affected by different conditions of the ALI system. Additionally, the viability and metabolic activity of A549 cells was studied following AgNP exposure. Particle deposition increased markedly with increasing aerosol flow rate and electrostatic field strength. The highest amount of deposited particles (2.2 μg cm–2) at cell-free conditions following 2 h exposure was observed for the highest flow rate (390 ml min–1) and the strongest electrostatic field (±2 kV). This was estimated corresponding to deposition efficiency of 94%. Cell viability was not affected after 2 h exposure to clean air in the ALI system. Cells exposed to AgNPs (0.45 and 0.74 μg cm–2) showed significantly (P < 0.05) reduced metabolic activities (64 and 46%, respectively). Our study shows that the ALI exposure system can be used for generating conditions that were more realistic for in vitro exposures, which enables improved mechanistic and toxicological studies of NPs in contact with human lung cells.

  • 347.
    Latvala, Siiri
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vare, Daniel
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Karlsson, Hanna
    Elihn, Karine
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In vitro genotoxicity assessment of airborne nickel nanoparticles using air-liquid interface exposure2016Manuscript (preprint) (Other academic)
  • 348.
    Latvala, Siiri
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Vare, Daniel
    Stockholm University, Faculty of Science, Department of Molecular Biosciences, The Wenner-Gren Institute.
    Karlsson, Hanna L.
    Elihn, Karine
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    In vitro genotoxicity of airborne Ni-NP in air-liquid interface2017In: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 37, no 12, p. 1420-1427Article in journal (Refereed)
    Abstract [en]

    Studies using advanced toxicological methods enabling in vitro conditions that are more realistic are currently needed for understanding the risks of pulmonary exposure to airborne nanoparticles. Owing to the carcinogenicity of certain nickel compounds, the increased production of nickel nanoparticles (Ni-NPs) raises occupational safety concerns. The aim of this study was to investigate the genotoxicity of airborne Ni-NPs using a recently developed air-liquid interface exposure system. The wild-type Chinese hamster lung fibroblast cell line (V79) was used and cytotoxicity, DNA damage and mutagenicity were studied by testing colony forming efficiency, alkaline DNA unwinding and HPRT mutation assays, respectively. Additionally, co-exposure to a PARP-1 inhibitor was performed to test possible involvement of base excision repair (BER) in repair of Ni-induced DNA damage. The results showed that cell viability was reduced significantly (to 45% and 46%) after 48hours Ni-NP exposure at concentrations of 0.15 and 0.32g cm(-2). DNA damage was significantly increased after Ni-NP exposure in the presence of the BER inhibitor indicating that Ni-NP-induced DNA damages are subsequently repaired by BER. Furthermore, there was no increased HPRT mutation frequency following Ni-NP exposure. In conclusion, this study shows that Ni-NP treatment of lung fibroblasts in an air-liquid interface system that mimics real-life exposure, results in increased DNA strand breaks and reduced cellular viability. These DNA lesions were repaired with BER in an error-free manner without resulting in mutations. This study also underlines the importance of appropriate quantification of the actual exposure concentrations during air-liquid interface exposure studies. The aim of this study was to investigate the genotoxicity of airborne Ni nanoparticles using a recently developed air-liquid interface exposure system that mimics real-life exposure. Cytotoxicity, DNA damage and mutagenicity were in the V79 cell line. Ni nanoparticle exposure of the cells in the air-liquid interface resulted in increased DNA strand breaks and reduced cellular viability at concentrations of 0.15 and 0.32 g cm (-2). These DNA lesions were repaired with BER in an error-free manner without resulting in mutations

  • 349. Lawler, Michael J.
    et al.
    Winkler, Paul M.
    Kim, Jaeseok
    Ahlm, Lars
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Trostl, Jasmin
    Praplan, Arnaud P.
    Schobesberger, Siegfried
    Kuerten, Andreas
    Kirkby, Jasper
    Bianchi, Federico
    Duplissy, Jonathan
    Hansel, Armin
    Jokinen, Tuija
    Keskinen, Helmi
    Lehtipalo, Katrianne
    Leiminger, Markus
    Petaja, Tuukka
    Rissanen, Matti
    Rondo, Linda
    Simon, Mario
    Sipila, Mikko
    Williamson, Christina
    Wimmer, Daniela
    Riipinen, Ilona
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Virtanen, Annele
    Smith, James N.
    Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD2016In: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, no 21, p. 13601-13618Article in journal (Refereed)
    Abstract [en]

    New particle formation driven by acid-base chemistry was initiated in the CLOUD chamber at CERN by introducing atmospherically relevant levels of gas-phase sulfuric acid and dimethylamine (DMA). Ammonia was also present in the chamber as a gas-phase contaminant from earlier experiments. The composition of particles with volume median diameters (VMDs) as small as 10 nm was measured by the Thermal Desorption Chemical Ionization Mass Spectrometer (TDCIMS). Particulate ammonium-to-dimethylaminium ratios were higher than the gas-phase ammonia-to-DMA ratios, suggesting preferential uptake of ammonia over DMA for the collected 10-30 nm VMD particles. This behavior is not consistent with present nanoparticle physicochemical models, which predict a higher dimethylaminium fraction when NH3 and DMA are present at similar gas-phase concentrations. Despite the presence in the gas phase of at least 100 times higher base concentrations than sulfuric acid, the recently formed particles always had measured base : acid ratios lower than 1 : 1. The lowest base fractions were found in particles below 15 nm VMD, with a strong size-dependent composition gradient. The reasons for the very acidic composition remain uncertain, but a plausible explanation is that the particles did not reach thermodynamic equilibrium with respect to the bases due to rapid heterogeneous conversion of SO2 to sulfate. These results indicate that sulfuric acid does not require stabilization by ammonium or dimethylaminium as acid-base pairs in particles as small as 10 nm.

  • 350. Legradi, Jessica
    et al.
    van Pomeren, Marinda
    Dahlberg, Anna-Karin
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry. Swedish University of Agricultural Sciences, Sweden.
    Legler, Juliette
    Effects of Hydroxylated Polybrominated Diphenyl Ethers in Developing Zebrafish Are Indicative of Disruption of Oxidative Phosphorylation2017In: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 18, no 5, article id 970Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have been detected in humans and wildlife. Using in vitro models, we recently showed that OH-PBDEs disrupt oxidative phosphorylation (OXPHOS), an essential process in energy metabolism. The goal of the current study was to determine the in vivo effects of OH-PBDE reported in marine wildlife. To this end, we exposed zebrafish larvae to 17 OH-PBDEs from fertilisation to 6 days of age, and determined developmental toxicity as well as OXPHOS disruption potential with a newly developed assay of oxygen consumption in living embryos. We show here that all OH-PBDEs tested, both individually and as mixtures, resulted in a concentration-dependant delay in development in zebrafish embryos. The most potent substances were 6'-OH-BDE47 and 6-OH-BDE49 (No-Effect-Concentration: 0.1 and 0.05 mu M). The first 24 h of development were the most sensitive, resulting in significant and irreversible developmental delay. All substances increased oxygen consumption, an effect indicative of OXPHOS disruption. Our results suggest that the induced developmental delay may be caused by disruption of OXPHOS. Though further studies are needed, our findings suggest that the environmental concentrations of some OH-PBDEs found in Baltic Sea wildlife in the Baltic Sea may be of toxicological concern.

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