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  • 401. Koike, M.
    et al.
    Ukita, J.
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Shiobara, M.
    Vitale, V.
    Lupi, A.
    Baumgardner, D.
    Ritter, C.
    Hermansen, O.
    Yamada, K.
    Pedersen, C. A.
    Year-Round In Situ Measurements of Arctic Low-Level Clouds: Microphysical Properties and Their Relationships With Aerosols2019Ingår i: Journal of Geophysical Research - Atmospheres, ISSN 2169-897X, E-ISSN 2169-8996, Vol. 124, nr 3, s. 1798-1822Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two years of continuous in situ measurements of Arctic low-level clouds have been made at the Mount Zeppelin Observatory (78 degrees 56N, 11 degrees 53E), in Ny-angstrom lesund, Spitsbergen. The monthly median value of the cloud particle number concentration (N-c) showed a clear seasonal variation: Its maximum appeared in May-July (658cm(-3)), and it remained low between October and March (87cm(-3)). At temperatures warmer than 0 degrees C, a clear correlation was found between the hourly N-c values and the number concentrations of aerosols with dry diameters larger than 70nm (N-70), which are proxies for cloud condensation nuclei (CCN). When clouds were detected at temperatures colder than 0 degrees C, some of the data followed the summertime N-c to N-70 relationship, while other data showed systematically lower N-c values. The lidar-derived depolarization ratios suggested that the former (CCN-controlled) and latter (CCN-uncontrolled) data generally corresponded to clouds consisting of supercooled water droplets and those containing ice particles, respectively. The CCN-controlled data persistently appeared throughout the year at Zeppelin. The aerosol-cloud interaction index (ACI=dlnN(c)/(3dlnN(70))) for the CCN-controlled data showed high sensitivities to aerosols both in the summer (clean air) and winter-spring (Arctic haze) seasons (0.220.03 and 0.250.02, respectively). The air parcel model calculations generally reproduced these values. The threshold diameters of aerosol activation (D-act), which account for the N-c of the CCN-controlled data, were as low as 30-50nm when N-70 was less than 30cm(-3), suggesting that new particle formation can affect Arctic cloud microphysics.

  • 402.
    Konovalenko, Lena
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Bradshaw, Clare
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Andersson, E.
    Lindqvist, Dennis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kautsky, U.
    Evaluation of factors influencing accumulation of stable Sr and Cs in lake and coastal fish2016Ingår i: Journal of Environmental Radioactivity, ISSN 0265-931X, E-ISSN 1879-1700, Vol. 160, s. 64-79Artikel i tidskrift (Refereegranskat)
    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.

  • 403.
    Kontkanen, Jenni
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Helsinki, Finland.
    Olenius, Tinja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kulmala, Markku
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Exploring the potential of nano-Kohler theory to describe the growth of atmospheric molecular clusters by organic vapors using cluster kinetics simulations2018Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 18, nr 18, s. 13733-13754Artikel i tidskrift (Refereegranskat)
    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.

  • 404. Kontkanen, Jenni
    et al.
    Olenius, Tinja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lehtipalo, Katrianne
    Vehkamäki, Hanna
    Kulmala, Markku
    Lehtinen, Kari E. J.
    Growth of atmospheric clusters involving cluster-cluster collisions: comparison of different growth rate methods2016Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, nr 9, s. 5545-5560Artikel i tidskrift (Refereegranskat)
    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.

  • 405. Koponen, Jani
    et al.
    Winkens, Kerstin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Airaksinen, Riikka
    Berger, Urs
    Vestergren, Robin
    Cousins, Ian T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karvonen, Anne M.
    Pekkanen, Juha
    Kiviranta, Hannu
    Longitudinal trends of per- and polyfluoroalkyl substances in children’s serumManuskript (preprint) (Övrigt vetenskapligt)
  • 406. Koponen, Jani
    et al.
    Winkens, Kerstin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Airaksinen, Riikka
    Berger, Urs
    Vestergren, Robin
    Cousins, Ian T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karvonen, Anne M.
    Pekkanen, Juha
    Kiviranta, Hannu
    Longitudinal trends of per- and polyfluoroalkyl substances in children's serum2018Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 121, s. 591-599Artikel i tidskrift (Refereegranskat)
    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.

  • 407. Korek, Michal
    et al.
    Johansson, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. 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, Sweden2017Ingår i: Journal of Exposure Science and Environmental Epidemiology, ISSN 1559-0631, E-ISSN 1559-064X, Vol. 27, nr 6, s. 575-581Artikel i tidskrift (Refereegranskat)
    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.

  • 408. Kosmach, D. A.
    et al.
    Sergienko, V. I.
    Dudarev, O. V.
    Kurilenko, A. V.
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Semiletov, I. P.
    Shakhova, N. E.
    Methane in the surface waters of Northern Eurasian marginal seas2015Ingår i: Doklady. Chemistry, ISSN 0012-5008, E-ISSN 1608-3113, Vol. 465, s. 281-285Artikel i tidskrift (Refereegranskat)
    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.

  • 409. Krecl, Patricia
    et al.
    Johansson, Christer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholm Environment and Health Administration, Sweden.
    Créso Targino, Admir
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Burman, Lars
    Trends in black carbon and size-resolved particle number concentrations and vehicle emission factors under real-world conditions2017Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 165, s. 155-168Artikel i tidskrift (Refereegranskat)
    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.

  • 410. 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
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    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 glycols2018Ingår i: Atmospheric Measurement Techniques, ISSN 1867-1381, E-ISSN 1867-8548, Vol. 11, nr 1, s. 49-63Artikel i tidskrift (Refereegranskat)
    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.

  • 411. Krogseth, Ingjerd S.
    et al.
    Undeman, Emma
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholms universitets Östersjöcentrum. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    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 Approach2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 21, s. 12489-12497Artikel i tidskrift (Refereegranskat)
    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).

  • 412. 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
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Zilitinkevich, S.
    Introduction: The Pan-Eurasian Experiment (PEEX) - multidisciplinary, multiscale and multicomponent research and capacity-building initiative2015Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, nr 22, s. 13085-13096Artikel i tidskrift (Refereegranskat)
    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.

  • 413. Kunzelmann, Marco
    et al.
    Winter, Martin
    Åberg, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hellenäs, Karl-Erik
    Rosén, Johan
    Non-targeted analysis of unexpected food contaminants using LC-HRMS2018Ingår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 410, nr 22, s. 5593-5602Artikel i tidskrift (Refereegranskat)
    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.

  • 414.
    Kylin, Henrik
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Linköping University, Sweden; Norwegian Institute for Air Research, Fram Centre, Norway.
    Hammar, Johan
    Mowrer, Jacques
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bouwman, Henk
    Edelstam, Carl
    Olsson, Mats
    Jensen, Sören
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Persistent organic pollutants in biota samples collected during the Ymer-80 expedition to the Arctic2015Ingår i: Polar Research, ISSN 0800-0395, E-ISSN 1751-8369, Vol. 34, artikel-id 21129Artikel i tidskrift (Refereegranskat)
    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.

  • 415. Kylin, Henrik
    et al.
    Svensson, Teresia
    Jensen, Sören
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Strachan, William M. J.
    Franich, Robert
    Bouwman, Hindrik
    The trans-continental distributions of pentachlorophenol and pentachloroanisole in pine needles indicate separate origins2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 229, s. 688-695Artikel i tidskrift (Refereegranskat)
    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.

  • 416.
    Lade, Steven J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. The Australian National University, Australia.
    Donges, Jonathan F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre. Potsdam Institute for Climate Impact Research, Germany.
    Fetzer, Ingo
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Anderies, John M.
    Beer, Christian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Cornell, Sarah E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Gasser, Thomas
    Norberg, Jon
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Richardson, Katherine
    Rockström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Steffen, Will
    Stockholms universitet, Naturvetenskapliga fakulteten, Stockholm Resilience Centre.
    Analytically tractable climate-carbon cycle feedbacks under 21st century anthropogenic forcing2018Ingår i: Earth System Dynamics, ISSN 2190-4979, E-ISSN 2190-4987, Vol. 9, nr 2, s. 507-523Artikel i tidskrift (Refereegranskat)
    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.

  • 417.
    Lagerström, Maria
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Occurrence and environmental risk assessment of antifouling paint biocides from leisure boats2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The use of biocidal antifouling (AF) paints is the most common way to prevent fouling on leisure boat hulls. The main aim of this thesis was to investigate the pathways through which AF biocides, past and present, may reach the environment through their use on leisure boats and to improve the risk assessment of biocidal AF paints intended for amateur use. The work presented focuses mainly on the Baltic Sea, with emphasis on regulation and risk assessment procedures in Sweden. A new method was developed for the quantification of nowadays banned organotin compounds (OTCs) such as tributyltin (TBT) in paint flakes (paper I). OTCs were detected in hull paint scrapings from three countries around the Baltic Sea. Thus, historic layers of organotin paint on leisure boats may constitute as sources of TBT to the marine environment. Total tin was identified as an indicator for the presence of OTCs on boat hulls, allowing for quicker identification of vessels in need of remediation. Nowadays, most AF paints tend to contain high amounts of copper (Cu) and zinc (Zn). The use of AF paints was shown to cause exceedance of guideline values for these two metals in soil, sediment and water in various investigated marinas (papers II and IV). The pollution of boatyard soil was linked to hull maintenance activities carried out over unprotected ground (paper II). AF paints were also found to impact both the concentration and speciation of dissolved Cu and Zn in two Baltic Sea marinas, with increased concentrations as well as an increased proportion of bioavailable species as a function of an increased number of moored boats (paper IV). A new method utilizing X-Ray Fluorescence (XRF) was used to derive the release rates of Cu and Zn in the field for five commercially available AF paints for amateur use (paper III). Salinity and paint properties were found to be important parameters affecting the release. The in situ release rates were also found to exceed those derived with current standardized release rate methods. Given the high release rates, none of the studied paints should have been approved for the Swedish market. This finding likely explains the exceedance of guideline values for dissolved Cu and Zn in investigated Baltic Sea marinas (paper IV). In conclusion, there is a need for caution when authorizing new biocides as the phasing out of banned substances can be a lengthy process due to their continued presence in historic paint layers. Additionally, paint-specific release rates determined under conditions reflecting the intended use of the product should be used for a more realistic environmental risk assessment of AF paints.

  • 418.
    Lagerström, Maria
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ferreira, João
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ytreberg, Erik
    Eriksson Wiklund, Ann-Kristin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Flawed risk assessment of antifouling paints leads to exceedance of guideline values in Baltic Sea marinasManuskript (preprint) (Övrigt vetenskapligt)
  • 419.
    Lagerström, Maria
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindgren, J. Fredrik
    Holmqvist, Albin
    Dahlström, Mia
    Ytreberg, Erik
    In situ release rates of Cu and Zn from commercial antifouling paints at different salinities2018Ingår i: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 127, s. 289-296Artikel i tidskrift (Refereegranskat)
    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.

  • 420.
    Lagerström, Maria
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Norling, Matz
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Metal contamination at recreational boatyards linked to the use of antifouling paints-investigation of soil and sediment with a field portable XRF2016Ingår i: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 23, nr 10, s. 10146-10157Artikel i tidskrift (Refereegranskat)
    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.

  • 421.
    Lagerström, Maria
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Strand, Jakob
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ytreberg, Erik
    Total tin and organotin speciation in historic layers of antifouling paint on leisure boat hulls2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 220, s. 1333-1341Artikel i tidskrift (Refereegranskat)
    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.

  • 422. Lagerström, Maria
    et al.
    Yngsell, Daniel
    Eklund, Britta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ytreberg, Erik
    Identification of commercial and recreational vessels coated with banned organotin paint through screening of tin by portable XRF2019Ingår i: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 362, s. 107-114Artikel i tidskrift (Refereegranskat)
    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.

  • 423. Lammel, Tobias
    et al.
    Wassmur, Britt
    Mackevica, Aiga
    Chen, Chang-Er L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. South China Normal University, China.
    Sturve, Joachim
    Mixture toxicity effects and uptake of titanium dioxide (TiO2) nanoparticles and 3,3 ',4,4 '-tetrachlorobiphenyl (PCB77) in juvenile brown trout following co-exposure via the diet2019Ingår i: Aquatic Toxicology, ISSN 0166-445X, E-ISSN 1879-1514, Vol. 213, artikel-id 105195Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Titanium dioxide nanoparticles (n-TiO2) are among the man-made nanomaterials that are predicted to be found at high concentrations in the aquatic environment. There, they likely co-exist with other chemical pollutants. Thus, n-TiO2 and other chemical pollutants can be taken up together or accumulate independently from each other in prey organisms of fish. This can lead to dietary exposure of fish to n-TiO2-chemical pollutant mixtures. In this study, we examine if simultaneous dietary exposure to n-TiO2 and 3,3',4,4'-Tetrachlorobiphenyl (PCB77)-used as a model compound for persistent organic pollutants with dioxin-like properties-can influence the uptake and toxicological response elicited by the respective other substance. Juvenile brown trout (Salmo trutta) were fed custom-made food pellets containing n-TiO2, PCB77 or n-TiO2+PCB77 mixtures for 15 days. Ti and PCB77 concentrations in the liver were measured by ICP-MS and GC-MS, respectively. Besides, n-TiO2 uptake was assessed using TEM. Combination effects on endpoints specific for PCB77 (i.e., cytochrome P450 1A (CYP1A) induction) and endpoints shared by both PCB77 and n-TiO2 (i.e., oxidative stress-related parameters) were measured in intestine and liver using RT-qPCR and enzyme activity assays. The results show that genes encoding for proteins/enzymes essential for tight junction function (zo-1) and ROS elimination (sod-1) were significantly upregulated in the intestine of fish exposed to n-TiO2 and PCB77 mixtures, but not in the single-substance treatments. Besides, n-TiO2 had a potentiating effect on PCB77-induced CYP1A and glutathione reductase (GR) expression/enzyme activity in the liver. This study shows that simultaneous dietary exposure to nanomaterials and traditional environmental pollutants might result in effects that are larger than observed for the substances alone, but that understanding the mechanistic basis of such effects remains challenging.

  • 424. Land, Magnus
    et al.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Cousins, Ian T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Herzke, Dorte
    Johansson, Jana H.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Martin, Jonathan W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. 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 review2018Ingår i: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 7, nr 1, artikel-id UNSP 4Artikel, forskningsöversikt (Refereegranskat)
    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.

  • 425. Land, Magnus
    et al.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Cousins, Ian T.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Herzke, Dorte
    Johansson, Jana
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    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 protocol2015Ingår i: Environmental Evidence, ISSN 2047-2382, E-ISSN 2047-2382, Vol. 4, artikel-id 3Artikel i tidskrift (Refereegranskat)
    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.

  • 426. Landhausser, Simon M.
    et al.
    Chow, Pak S.
    Dickman, L. Turin
    Furze, Morgan E.
    Kuhlman, Iris
    Schmid, Sandra
    Wiesenbauer, Julia
    Wild, Birgit
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. 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 carbohydrates2018Ingår i: Tree Physiology, ISSN 0829-318X, E-ISSN 1758-4469, Vol. 38, nr 12, s. 1764-1778Artikel i tidskrift (Refereegranskat)
    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.

  • 427. 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
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    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 region2016Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, nr 22, s. 14421-14461Artikel i tidskrift (Refereegranskat)
    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.

  • 428. Larsson, Kristin
    et al.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sellström, Ulla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sahlström, Leena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lindh, Christian H.
    Berglund, Marika
    Brominated Flame Retardants and Organophosphate Esters in Preschool Dust and Children's Hand Wipes2018Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, nr 8, s. 4878-4888Artikel i tidskrift (Refereegranskat)
    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.

  • 429.
    Latvala, Siiri
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Development and comparison of in vitro toxicity methods for nanoparticles: Focus on lung cell exposure2016Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 430.
    Latvala, Siiri
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lung toxicity of airborne nanoparticles - focus on development of an advanced in vitro exposure system2015Licentiatavhandling, sammanläggning (Övrigt vetenskapligt)
    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.

  • 431.
    Latvala, Siiri
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hedberg, Jonas
    Di Bucchianico, Sebastiano
    Möller, Lennart
    Odnevall Wallinder, Inger
    Elihn, Karine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlsson, Hanna L.
    Nickel release, ROS generation and toxicity of Ni and NiO micro- and nanoparticles2016Ingår i: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 11, nr 7, artikel-id e0159684Artikel i tidskrift (Refereegranskat)
    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.

  • 432.
    Latvala, Siiri
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Hedberg, Jonas
    Möller, Lennart
    Odnevall Wallinder, Inger
    Karlsson, Hanna L.
    Elihn, Karine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Optimization of an air–liquid interface exposure system for assessing toxicity of airborne nanoparticles2016Ingår i: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 36, nr 10, s. 1294-1301Artikel i tidskrift (Refereegranskat)
    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.

  • 433.
    Latvala, Siiri
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vare, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Karlsson, Hanna
    Elihn, Karine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    In vitro genotoxicity assessment of airborne nickel nanoparticles using air-liquid interface exposure2016Manuskript (preprint) (Övrigt vetenskapligt)
  • 434.
    Latvala, Siiri
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vare, Daniel
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för molekylär biovetenskap, Wenner-Grens institut.
    Karlsson, Hanna L.
    Elihn, Karine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    In vitro genotoxicity of airborne Ni-NP in air-liquid interface2017Ingår i: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 37, nr 12, s. 1420-1427Artikel i tidskrift (Refereegranskat)
    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

  • 435. Lawler, Michael J.
    et al.
    Winkler, Paul M.
    Kim, Jaeseok
    Ahlm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    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
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Virtanen, Annele
    Smith, James N.
    Unexpectedly acidic nanoparticles formed in dimethylamine-ammonia-sulfuric-acid nucleation experiments at CLOUD2016Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, nr 21, s. 13601-13618Artikel i tidskrift (Refereegranskat)
    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.

  • 436. Legradi, Jessica
    et al.
    van Pomeren, Marinda
    Dahlberg, Anna-Karin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish University of Agricultural Sciences, Sweden.
    Legler, Juliette
    Effects of Hydroxylated Polybrominated Diphenyl Ethers in Developing Zebrafish Are Indicative of Disruption of Oxidative Phosphorylation2017Ingår i: International Journal of Molecular Sciences, ISSN 1422-0067, E-ISSN 1422-0067, Vol. 18, nr 5, artikel-id 970Artikel i tidskrift (Refereegranskat)
    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.

  • 437. Lehnert, Kristina
    et al.
    Siebert, Ursula
    Reissmann, Kristina
    Bruhn, Regina
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Baltic Sea Research Institute, Germany.
    Müller, Gundi
    van Elk, Cornelis E.
    Ciurkiewicz, Malgorzata
    Baumgärtner, Wolfgang
    Beineke, Andreas
    Cytokine expression and lymphocyte proliferative capacity in diseased harbor porpoises (Phocoena phocoena) - Biomarkers for health assessment in wildlife cetaceans2019Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 247, s. 783-791Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Harbor porpoises (Phocoena phocoena) in the North and Baltic Seas are exposed to anthropogenic influences including acoustic stress and environmental contaminants. In order to evaluate immune responses in healthy and diseased harbor porpoise cells, cytokine expression analyses and lymphocyte proliferation assays, together with toxicological analyses were performed in stranded and bycaught animals as well as in animals kept in permanent human care. Severely diseased harbor porpoises showed a reduced proliferative capacity of peripheral blood lymphocytes together with diminished transcription of transforming growth factor-beta and tumor necrosis factor-alpha compared to healthy controls. Toxicological analyses revealed accumulation of polychlorinated biphenyls (PCBs), dichlorodiphenyldichloroethylene (DDE), and dichlorodiphenyltrichloroethane (DDT) in harbor porpoise blood samples. Correlation analyses between blood organochlorine levels and immune parameters revealed no direct effects of xenobiotics upon lymphocyte proliferation or cytokine transcription, respectively. Results reveal an impaired function of peripheral blood leukocytes in severely diseased harbor porpoises, indicating immune exhaustion and increased disease susceptibility.

  • 438. Lehtipalo, Katrianne
    et al.
    Rondo, Linda
    Kontkanen, Jenni
    Schobesberger, Siegfried
    Jokinen, Tuija
    Sarnela, Nina
    Kürten, Andreas
    Ehrhart, Sebastian
    Franchin, Alessandro
    Nieminen, Tuomo
    Riccobono, Francesco
    Sipilä, Mikko
    Yli-Juuti, Taina
    Duplissy, Jonathan
    Adamov, Alexey
    Ahlm, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Almeida, Joao
    Amorim, Antonio
    Bianchi, Federico
    Breitenlechner, Martin
    Dommen, Josef
    Downard, Andrew J.
    Dunne, Eimear M.
    Flagan, Richard C.
    Guida, Roberto
    Hakala, Jani
    Hansel, Armin
    Jud, Werner
    Kangasluoma, Juha
    Kerminen, Veli-Matti
    Keskinen, Helmi
    Kim, Jaeseok
    Kirkby, Jasper
    Kupc, Agnieszka
    Kupiainen-Määttä, Oona
    Laaksonen, Ari
    Lawler, Michael J.
    Leiminger, Markus
    Mathot, Serge
    Olenius, Tinja
    Ortega, Ismael K.
    Onnela, Antti
    Petäjä, Tuukka
    Praplan, Arnaud
    Rissanen, Matti P.
    Ruuskanen, Taina
    Santos, Filipe D.
    Schallhart, Simon
    Schnitzhofer, Ralf
    Simon, Mario
    Smith, James N.
    Tröstl, Jasmin
    Tsagkogeorgas, Georgios
    Tome, Antonio
    Vaattovaara, Petri
    Vehkamäki, Hanna
    Vrtala, Aron E.
    Wagner, Paul E.
    Williamson, Christina
    Wimmer, Daniela
    Winkler, Paul M.
    Virtanen, Annele
    Donahue, Neil M.
    Carslaw, Kenneth S.
    Baltensperger, Urs
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Curtius, Joachim
    Worsnop, Douglas R.
    Kulmala, Markku
    The effect of acid-base clustering and ions on the growth of atmospheric nano-particles2016Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 7, artikel-id 11594Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The growth of freshly formed aerosol particles can be the bottleneck in their survival to cloud condensation nuclei. It is therefore crucial to understand how particles grow in the atmosphere. Insufficient experimental data has impeded a profound understanding of nano-particle growth under atmospheric conditions. Here we study nano-particle growth in the CLOUD (Cosmics Leaving OUtdoors Droplets) chamber, starting from the formation of molecular clusters. We present measured growth rates at sub-3 nm sizes with different atmospherically relevant concentrations of sulphuric acid, water, ammonia and dimethylamine. We find that atmospheric ions and small acid-base clusters, which are not generally accounted for in the measurement of sulphuric acid vapour, can participate in the growth process, leading to enhanced growth rates. The availability of compounds capable of stabilizing sulphuric acid clusters governs the magnitude of these effects and thus the exact growth mechanism. We bring these observations into a coherent framework and discuss their significance in the atmosphere.

  • 439. Lehtipalo, Katrianne
    et al.
    Yan, Chao
    Dada, Lubna
    Bianchi, Federico
    Xiao, Mao
    Wagner, Robert
    Stolzenburg, Dominik
    Ahonen, Lauri R.
    Amorim, Antonio
    Baccarini, Andrea
    Bauer, Paulus S.
    Baumgartner, Bernhard
    Bergen, Anton
    Bernhammer, Anne-Kathrin
    Breitenlechner, Martin
    Brilke, Sophia
    Buchholz, Angela
    Mazon, Stephany Buenrostro
    Chen, Dexian
    Chen, Xuemeng
    Dias, Antonio
    Dommen, Josef
    Draper, Danielle C.
    Duplissy, Jonathan
    Ehn, Mikael
    Finkenzeller, Henning
    Fischer, Lukas
    Frege, Carla
    Fuchs, Claudia
    Garmash, Olga
    Gordon, Hamish
    Hakala, Jani
    He, Xucheng
    Heikkinen, Liine
    Heinritzi, Martin
    Helm, Johanna C.
    Hofbauer, Victoria
    Hoyle, Christopher R.
    Jokinen, Tuija
    Kangasluoma, Juha
    Kerminen, Veli-Matti
    Kim, Changhyuk
    Kirkby, Jasper
    Kontkanen, Jenni
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Helsinki, Finland.
    Kuerten, Andreas
    Lawler, Michael J.
    Mai, Huajun
    Mathot, Serge
    Mauldin, Roy L.
    Molteni, Ugo
    Nichman, Leonid
    Nie, Wei
    Nieminen, Tuomo
    Ojdanic, Andrea
    Onnela, Antti
    Passananti, Monica
    Petaja, Tuukka
    Piel, Felix
    Pospisilova, Veronika
    Quelever, Lauriane L. J.
    Rissanen, Matti P.
    Rose, Clemence
    Sarnela, Nina
    Schallhart, Simon
    Schuchmann, Simone
    Sengupta, Kamalika
    Simon, Mario
    Sipila, Mikko
    Tauber, Christian
    Tome, Antonio
    Trostl, Jasmin
    Vaisanen, Olli
    Vogel, Alexander L.
    Volkamer, Rainer
    Wagner, Andrea C.
    Wang, Mingyi
    Weitz, Lena
    Wimmer, Daniela
    Ye, Penglin
    Ylisirnio, Arttu
    Zha, Qiaozhi
    Carslaw, Kenneth S.
    Curtius, Joachim
    Donahue, Neil M.
    Flagan, Richard C.
    Hansel, Armin
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tampere University of Technology, Finland.
    Virtanen, Annele
    Winkler, Paul M.
    Baltensperger, Urs
    Kulmala, Markku
    Worsnop, Douglas R.
    Multicomponent new particle formation from sulfuric acid, ammonia, and biogenic vapors2018Ingår i: Science Advances, E-ISSN 2375-2548, Vol. 4, nr 12, artikel-id eaau5363Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A major fraction of atmospheric aerosol particles, which affect both air quality and climate, form from gaseous precursors in the atmosphere. Highly oxygenated organic molecules (HOMs), formed by oxidation of biogenic volatile organic compounds, are known to participate in particle formation and growth. However, it is not well understood how they interact with atmospheric pollutants, such as nitrogen oxides (NOx) and sulfur oxides (SOx) from fossil fuel combustion, as well as ammonia (NH3) from livestock and fertilizers. Here, we show how NOx suppresses particle formation, while HOMs, sulfuric acid, and NH3 have a synergistic enhancing effect on particle formation. We postulate a novel mechanism, involving HOMs, sulfuric acid, and ammonia, which is able to closely reproduce observations of particle formation and growth in daytime boreal forest and similar environments. The findings elucidate the complex interactions between biogenic and anthropogenic vapors in the atmospheric aerosol system.

  • 440. Lenton, Timothy M.
    et al.
    Dahl, Tais W.
    Daines, Stuart J.
    Mills, Benjamin J. W.
    Ozaki, Kazumi
    Saltzman, Matthew R.
    Porada, Philipp
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Earliest land plants created modern levels of atmospheric oxygen2016Ingår i: Proceedings of the National Academy of Sciences of the United States of America, ISSN 0027-8424, E-ISSN 1091-6490, Vol. 113, nr 35, s. 9704-9709Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The progressive oxygenation of the Earth's atmosphere was pivotal to the evolution of life, but the puzzle of when and how atmospheric oxygen (O-2) first approached modern levels (similar to 21%) remains unresolved. Redox proxy data indicate the deep oceans were oxygenated during 435-392 Ma, and the appearance of fossil charcoal indicates O-2 > 15-17% by 420-400 Ma. However, existing models have failed to predict oxygenation at this time. Here we show that the earliest plants, which colonized the land surface from similar to 470 Ma onward, were responsible for this mid-Paleozoic oxygenation event, through greatly increasing global organic carbon burialthe net long-term source of O-2. We use a trait-based ecophysiological model to predict that cryptogamic vegetation cover could have achieved similar to 30% of today's global terrestrial net primary productivity by similar to 445 Ma. Data from modern bryophytes suggests this plentiful early plant material had a much higher molar C:P ratio (similar to 2,000) than marine biomass (similar to 100), such that a given weathering flux of phosphorus could support more organic carbon burial. Furthermore, recent experiments suggest that early plants selectively increased the flux of phosphorus (relative to alkalinity) weathered from rocks. Combining these effects in a model of long-term biogeochemical cycling, we reproduce a sustained +2% increase in the carbonate carbon isotope (delta C-13) record by similar to 445 Ma, and predict a corresponding rise in O-2 to present levels by 420-400 Ma, consistent with geochemical data. This oxygen rise represents a permanent shift in regulatory regime to one where fire-mediated negative feedbacks stabilize high O-2 levels.

  • 441. Levie, Deborah
    et al.
    Derakhshan, Arash
    Shu, Huan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Broeren, Maarten A. C.
    de Poortere, Ralph A.
    Peeters, Robin P.
    Bornehag, Carl-Gustaf
    Demeneix, Barbara
    Korevaar, Tim I. M.
    The Association of Maternal Iodine Status in Early Pregnancy with Thyroid Function in the Swedish Environmental Longitudinal, Mother and Child, Asthma and Allergy Study2019Ingår i: Thyroid, ISSN 1050-7256, E-ISSN 1557-9077, Vol. 29, nr 11, s. 1660-1668Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Severe maternal iodine deficiency can impact fetal brain development through effects on maternal and/or fetal thyroid hormone availability. The effects of mild-to-moderate iodine deficiency on thyroid function are less clear. The aim was to investigate the association of maternal urinary iodine concentration corrected for creatinine (UI/Creat) with thyroid function and autoantibodies in a mild-to-moderate iodine-deficient pregnant population.

    Methods: This study was embedded within the Swedish Environmental Longitudinal, Mother and child, Asthma and allergy (SELMA) study. Clinical reference ranges were determined by the 2.5th and 97.5th population-based percentile cutoffs. The associations of UI/Creat with thyrotropin (TSH), free thyroxine (fT4), free triiodothyronine (fT3), total T4 (TT4), and total T3 (TT3) were studied using multivariable linear regression in thyroid peroxidase antibody (TPOAb)-negative women. The association of UI/Creat with TPOAb and thyroglobulin antibody (TgAb) positivity was analyzed using multivariable logistic regression.

    Results: Urinary iodine and thyroid function were measured at a median (95% range) gestational age of 10 (6-14) weeks in 2009 women. The median (95% range) UI/Creat was 85 mu g/g (36-386) and the UI/Creat was below 150 mu g/g in 80.1% of women. Reference ranges did not differ substantially by UI/Creat. A lower UI/Creat was associated with a lower TSH (p = 0.027), a higher TT4 (p = 0.032), and with a corresponding trend toward slightly higher fT4 (p = 0.081), fT3 (p = 0.079), and TT3 (p = 0.10). UI/Creat was not associated with the fT4/fT3 (p = 0.94) or TT4/TT3 ratios (p = 0.63). Women with a UI/Creat of 150-249 mu g/g had the lowest prevalence of TPOAb positivity (6.1%), while women with a UI/Creat of <150 mu g/g had a higher prevalence (11.0%, odds ratio [OR] confidence interval [95% CI] 1.84 [1.07-3.20], p = 0.029). Women with a UI/Creat >= 500 mu g/g showed the highest prevalence and a higher risk of TPOAb positivity, however, only a small proportion of women had such a UI/Creat (12.5%, OR, [95% CI] 2.36 [0.54-10.43], p = 0.26).

    Conclusions: We could not identify any meaningful differences in thyroid function reference ranges. Lower iodine availability was associated with a slightly lower TSH and a higher TT4. Women with adequate iodine intake had the lowest risk of TPOAb positivity.

  • 442. Lewandowski, Jörg
    et al.
    Arnon, Shai
    Banks, Eddie
    Batelaan, Okke
    Betterle, Andrea
    Broecker, Tabea
    Coll, Claudia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Drummond, Jennifer D.
    Garcia, Jaime Gaona
    Galloway, Jason
    Gomez-Velez, Jesus
    Grabowski, Robert C.
    Herzog, Skuyler P.
    Hinkelmann, Reinhard
    Höhne, Anja
    Hollender, Juliane
    Horn, Marcus A.
    Jaeger, Anna
    Krause, Stefan
    Löchner Prats, Adrian
    Magliozzi, Chiara
    Meinikmann, Karin
    Mojarrad, Brian Babak
    Mueller, Birgit Maria
    Peralta-Maraver, Ignacio
    Popp, Andrea L.
    Posselt, Malte
    Putschew, Anke
    Radke, Michael
    Raza, Muhammad
    Riml, Joakim
    Robertson, Anne
    Rutere, Cyrus
    Schaper, Jonas L.
    Schirmer, Mario
    Schulz, Hanna
    Shanafield, Margaret
    Singh, Tanu
    Ward, Adam S.
    Wolke, Philipp
    Wörman, Anders
    Wu, Liwen
    Is the Hyporheic Zone Relevant beyond the Scientific Community?2019Ingår i: Water, ISSN 2073-4441, E-ISSN 2073-4441, Vol. 11, nr 11, artikel-id 2230Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rivers are important ecosystems under continuous anthropogenic stresses. The hyporheic zone is a ubiquitous, reactive interface between the main channel and its surrounding sediments along the river network. We elaborate on the main physical, biological, and biogeochemical drivers and processes within the hyporheic zone that have been studied by multiple scientific disciplines for almost half a century. These previous efforts have shown that the hyporheic zone is a modulator for most metabolic stream processes and serves as a refuge and habitat for a diverse range of aquatic organisms. It also exerts a major control on river water quality by increasing the contact time with reactive environments, which in turn results in retention and transformation of nutrients, trace organic compounds, fine suspended particles, and microplastics, among others. The paper showcases the critical importance of hyporheic zones, both from a scientific and an applied perspective, and their role in ecosystem services to answer the question of the manuscript title. It identifies major research gaps in our understanding of hyporheic processes. In conclusion, we highlight the potential of hyporheic restoration to efficiently manage and reactivate ecosystem functions and services in river corridors.

  • 443.
    Lewinschal, Anna
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Ekman, Annica M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Hansson, Hans-Christen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sand, Maria
    Berntsen, Terje K.
    Langner, Joakim
    Local and remote temperature response of regional SO2 emissions2019Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 19, nr 4, s. 2385-2403Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Short-lived anthropogenic climate forcers (SLCFs), such as sulfate aerosols, affect both climate and air quality. Despite being short-lived, these forcers do not affect temperatures only locally; regions far away from the emission sources are also affected. Climate metrics are often used in a policy context to compare the climate impact of different anthropogenic forcing agents. These metrics typically relate a forcing change in a certain region with a temperature change in another region and thus often require a separate model to convert emission changes to radiative forcing (RF) changes. In this study, we used a coupled Earth system model, NorESM (Norwegian Earth System Model), to calculate emission-to-temperature-response metrics for sulfur dioxide (SO2) emission changes in four different policy-relevant regions: Europe (EU), North America (NA), East Asia (EA) and South Asia (SA). We first increased the SO2 emissions in each individual region by an amount giving approximately the same global average radiative forcing change (-0.45 Wm(-2)). The global mean temperature change per unit sulfur emission compared to the control experiment was independent of emission region and equal to similar to 0.006 K(TgSyr(-1))(-1). On a regional scale, the Arctic showed the largest temperature response in all experiments. The second largest temperature change occurred in the region of the imposed emission increase, except when South Asian emissions were changed; in this experiment, the temperature response was approximately the same in South Asia and East Asia. We also examined the non-linearity of the temperature response by removing all anthropogenic SO2 emissions over Europe in one experiment. In this case, the temperature response (both global and regional) was twice that in the corresponding experiment with a European emission increase. This non-linearity in the temperature response is one of many uncertainties associated with the use of simplified climate metrics.

  • 444. Li, Chaoliu
    et al.
    Bosch, Carme
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kang, Shichang
    Andersson, August
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Chen, Pengfei
    Zhang, Qianggong
    Cong, Zhiyuan
    Chen, Bing
    Qin, Dahe
    Gustafsson, Örjan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sources of black carbon to the Himalayan-Tibetan Plateau glaciers2016Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 7, artikel-id 12574Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Combustion-derived black carbon (BC) aerosols accelerate glacier melting in the Himalayas and in Tibet (the Third Pole (TP)), thereby limiting the sustainable freshwater supplies for billions of people. However, the sources of BC reaching the TP remain uncertain, hindering both process understanding and efficient mitigation. Here we present the source-diagnostic Delta C-14/delta C-13 compositions of BC isolated from aerosol and snowpit samples in the TP. For the Himalayas, we found equal contributions from fossil fuel (46 +/- 11%) and biomass (54 +/- 11%) combustion, consistent with BC source fingerprints from the Indo-Gangetic Plain, whereas BC in the remote northern TP predominantly derives from fossil fuel combustion (66 +/- 16%), consistent with Chinese sources. The fossil fuel contributions to BC in the snowpits of the inner TP are lower (30 +/- 10%), implying contributions from internal Tibetan sources (for example, yak dung combustion). Constraints on BC sources facilitate improved modelling of climatic patterns, hydrological effects and provide guidance for effective mitigation actions.

  • 445. Li, Qian
    et al.
    Wang, Meng
    Duan, Lei
    Qiu, Yanling
    Ma, Taowu
    Chen, Ling
    Breitholtz, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bergman, Åke
    Zhao, Jianfu
    Hecker, Markus
    Wu, Lingling
    Multiple biomarker responses in caged benthic gastropods Bellamya aeruginosa after in situ exposure to Taihu Lake in China2018Ingår i: Environmental Sciences Europe, ISSN 2190-4707, E-ISSN 2190-4715, Vol. 30, artikel-id 34Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Freshwater sediments have been recognized as a long-term sink and potential source for environmental pollutants released into the aquatic ecosystems. In this study, the sediment quality of Taihu Lake, which is susceptible to anthropogenic contamination, was assessed by a combination of chemical analytical and biological end points. Specifically, the snail Bellamya aeruginosa was caged in situ at two locations representing different pollution levels for different exposure times (7, 14 and 21 days). At each of these time points, biochemical parameters, i.e., phase I biotransformation enzymes ethoxyresorufin-O-deethylase (EROD), the antioxidant enzymes superoxide dismutase and catalase, reactive oxygen species, protein carbonyl content and lipid peroxidation, were evaluated in the hepato-pancreas of snails. In addition, surface sediments were collected for analysis of contaminants of concern, including inorganic pollutants, organochlorine pesticides, polychlorinated biphenyls and polybrominated diphenyl ethers.

    Results: Chemical analyses revealed that sediments from Taihu Lake were contaminated with trace elements and organic pollutants. Concentrations of trace elements (Cu, Ni and As) and organochlorinated pesticides (4,4'-DDE) exceeded their corresponding threshold effect level according to the sediment quality assessment values for freshwater ecosystems in Canada, indicating that adverse biological effects may occur. All biomarkers, except EROD activity, were induced in snails during all exposure times. The integrated biomarker response index (IBR) indicated that during the initial exposure phase (7 days), B. aeruginosa were subjected to significant environmental stress, which diminished during later sampling time points.

    Conclusions: Results showed that IBR correlated well with the levels of environmental contaminants, demonstrating the applicability of this biomonitoring approach to complex environmental exposure scenarios.

  • 446. Li, Wei
    et al.
    Ciais, Philippe
    Peng, Shushi
    Yue, Chao
    Wang, Yilong
    Thurner, Martin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Saatchi, Sassan S.
    Arneth, Almut
    Avitabile, Valerio
    Carvalhais, Nuno
    Harper, Anna B.
    Kato, Etsushi
    Koven, Charles
    Liu, Yi Y.
    Nabel, Julia E. M. S.
    Pan, Yude
    Pongratz, Julia
    Poulter, Benjamin
    Pugh, Thomas A. M.
    Santoro, Maurizio
    Sitch, Stephen
    Stocker, Benjamin D.
    Viovy, Nicolas
    Wiltshire, Andy
    Yousefpour, Rasoul
    Zaehle, Soenke
    Land-use and land-cover change carbon emissions between 1901 and 2012 constrained by biomass observations2017Ingår i: Biogeosciences, ISSN 1726-4170, E-ISSN 1726-4189, Vol. 14, nr 22, s. 5053-5067Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The use of dynamic global vegetation models (DGVMs) to estimate CO2 emissions from land-use and land-cover change (LULCC) offers a new window to account for spatial and temporal details of emissions and for ecosystem processes affected by LULCC. One drawback of LULCC emissions from DGVMs, however, is lack of observation constraint. Here, we propose a new method of using satellite-and inventory-based biomass observations to constrain historical cumulative LULCC emissions (E-LUC(c)) from an ensemble of nine DGVMs based on emerging relationships between simulated vegetation biomass and E-LUC(c). This method is applicable on the global and regional scale. The original DGVM estimates of E-LUC(c) range from 94 to 273 PgC during 1901-2012. After constraining by current biomass observations, we derive a best estimate of 155 +/- 50 PgC (1 sigma Gaussian error). The constrained LULCC emissions are higher than prior DGVM values in tropical regions but significantly lower in North America. Our emergent constraint approach independently verifies the median model estimate by biomass observations, giving support to the use of this estimate in carbon budget assessments. The uncertainty in the constrained Ec LUC is still relatively large because of the uncertainty in the biomass observations, and thus reduced uncertainty in addition to increased accuracy in biomass observations in the future will help improve the constraint. This constraint method can also be applied to evaluate the impact of land-based mitigation activities.

  • 447.
    Li, Zhe
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Fate of Pharmaceuticals and Their Transformation Products in Rivers: An integration of target analysis and screening methods to study attenuation processes2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    Pharmaceuticals are environmental contaminants causing steadily increasing concern due to their high usage, ubiquitous distribution in the aquatic environment, and potential to exert adverse effects on the ecosystems. After being discharged from wastewater treatment plants (WWTPs), pharmaceuticals can undergo transformation processes in surface waters, of which microbial degradation in river sediments is considered highly significant. In spite of a substantial number of studies on the occurrence of pharmaceuticals in aquatic systems, a comprehensive understanding of their environmental fate is still limited. First of all, very few consistent datasets from lab-based experiments to field studies exist to allow for a straightforward comparison of observations. Secondly, data on the identity and occurrence of transformation products (TPs) is insufficient and the relation of the behavior of TPs to that of their parent compounds (PCs) is poorly understood. In this thesis, these knowledge gaps were addressed by integrating the TP identification using suspect/non-target screening approaches and PC/TP fate determination. The overarching objective was to improve the understanding of the fate of pharmaceuticals in rivers, with a specific focus on water-sediment interactions, and formation and behavior of TPs. In paper I, 11 pharmaceutical TPs were identified in water-sediment incubation experiments using non-target screening. Bench-scale flume experiments were conducted in paper II to simultaneously investigate the behavior of PCs and TPs in both water and sediment compartments under more complex and realistic hydraulic conditions. The results illustrate that water-sediment interactions play a significant role for efficient attenuation of PCs, and demonstrate that TPs are formed in sediment and released back to surface water. In paper III the environmental behavior of PCs along stretches of four wastewater-impacted rivers was related to that of their TPs. The attenuation of PCs is highly compound and site specific. The highest attenuation rates of the PCs were observed in the river with the most efficient river water-pore water exchange. This research also indicates that WWTPs can be a major source of TPs to the receiving waters. In paper IV, suspect screening with a case-control concept was applied on water samples collected at both ends of the river stretches, which led to the identification of several key TPs formed along the stretches. The process-oriented strategies applied in this thesis provide a basis for prioritizing and identifying the critical PCs and TPs with respect to environmental relevance in future fate studies.

  • 448.
    Li, Zhe
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kaserzon, Sarin L.
    Plassmann, Merle M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gómez Ramos, María José
    Radke, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    A strategic screening approach to identify transformation products of organic micropollutants along riversManuskript (preprint) (Övrigt vetenskapligt)
    Abstract [en]

    Many transformation products (TPs) from organic micropollutants are not included in routine monitoring programs due to limited knowledge of their occurrence and fate. An efficient method to identify and prioritize critical compounds in terms of environmental relevance is needed. In this study we applied a strategic screening approach based on a case-control concept to identify TPs with an increasing trend along a stretch in four wastewater-impacted rivers. Time-integrated samples were taken over one week at both ends of a river stretch downstream of a wastewater treatment plant (WWTP) outfall. The screening procedure consisted of three major steps: i) screening for parent compounds (PCs) attenuating along the stretch; ii) prediction of TPs for these PCs; and iii) screening for TPs with an increasing trend along the stretch. In total, 48 organic micropollutants were tentatively identified, of which 32 were decreasing along the stretches. From these PCs, 1315 TPs were predicted and eight out of which were tentatively identified with increasing concentrations along the stretches. Generally, good correlations were observed between the suspect screening results from this study and previous target analysis results on the same samples, suggesting high confidence of our screening approach. The case-control concept was proven efficient and reliable for identifying environmental relevant TPs formed along rivers. 

  • 449.
    Li, Zhe
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kaserzon, Sarit L.
    Plassmann, Merle M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gómez Ramos, Maria José
    Radke, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    A strategic screening approach to identify transformation products of organic micropollutants formed in natural waters2017Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, nr 4, s. 488-498Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Many transformation products (TPs) from organic micropollutants are not included in routine environmental monitoring programs due to limited knowledge of their occurrence and fate. An efficient method to identify and prioritize critical compounds in terms of environmental relevance is needed. In this study, we applied a strategic screening approach based on a case-control concept to identify TPs formed along wastewater-impacted rivers. Time-integrated samples were collected over one week at both ends of a river stretch downstream of a wastewater treatment plant (WWTP) outfall and were analyzed by ultrahigh performance liquid chromatography interfaced with quadrupole time-of-flight mass spectrometry (UHPLC-QToF-MS/MS). The screening procedure of the high-resolution MS (HRMS) datasets consisted of three major steps: (i) screening for parent compounds (PCs) attenuated along the stretch; (ii) prediction of potential TPs from these PCs; and (iii) screening for TPs from this list with an increasing trend along the stretch. In total, 32 PCs decreased along the investigated river stretches. From these PCs, eight TPs had increasing concentrations along the studied stretches and could be tentatively identified. The identification of one TP (benzamide) was confirmed by its corresponding reference standard, while no standards were available for the remaining TPs.

  • 450.
    Li, Zhe
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Biodegradation of Chemicals in Unspiked Surface Waters Downstream of Wastewater Treatment Plants2019Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, nr 4, s. 1884-1892Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The OECD 309 guideline uses spiked incubation tests to provide data on biodegradation kinetics in surface waters. However, potential limitations of spiking test chemicals into the studied water have not been investigated. We conducted the OECD 309 test with unspiked surface water relying on chemical residues present in the water. Parallel experiments were conducted with the same water spiked with 13 chemicals at higher concentrations (50 mu g L-1). Six chemicals detected in both the spiked and the unspiked systems were biodegraded. For each chemical the concentration change over time differed between the systems. Tramadol and venlafaxine showed constant concentrations in the spiked systems but increasing concentrations in the unspiked systems. Atenolol and metoprolol showed first-order elimination with no lag in the unspiked systems, compared to a lag of 15-28 d followed by zero-order elimination kinetics in the spiked systems. Acesulfame was only slightly degraded (<50%) in the unspiked system, while removal was complete (>99%) in the spiked systems. Gabapentin displayed a complex behavior where the features differed markedly between the spiked and the unspiked systems. We conclude that spiking can strongly influence biodegradation, reducing the environmental relevance of test results. Under some conditions biodegradation can be measured in unspiked natural waters instead.

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