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  • 851.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Alsberg, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bogdal, Christian
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Berger, Urs
    Gao, Wei
    Wang, Yawei
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Deconvolution of Soft Ionization Mass Spectra of Chlorinated Paraffins To Resolve Congener Groups2016Ingår i: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 88, nr 18, s. 8980-8988Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We describe and illustrate a three-step data-processing approach that enables individual congener groups of chlorinated-paraffins (CPs) to be resolved in mass spectra obtained from either-of two soft ionization methods: electron capture negative-ionization mass spectrometry (ECNI-MS) or atmospheric pressure chemical ionization mass spectrometry (APCI-MS). In the first step, general fragmentation pathways of CPs are deduced from analysis of mass spectra of individual CP congeners. In the-Second step, all possible fragment ions in the general fragmentation pathways of CPs with 10 to 20 carbon atoms are enumerated and compared to mass spectra of CP mixture standards, and a deconvolution algorithm is applied to identify fragment ions that are actually observed. In the third step, isotope permutations of the observed fragment ions are calculated and used to identify isobaric overlaps, so that mass intensities of indivichial CP congener groups can be deconvolved from the unresolved isobaric ion signal intensities in mass spectra. For a specific instrument; the three steps only need to be done once to enable deconvolution of CPs in unknown samples. This approach enables congener group-level resolution of CP mixtures in environmental samples, and: it opens up the possibility, for quantification of congener group.

  • 852.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Alsberg, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bogdal, Christian
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    de Wit, Cynthia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Modelling isotopic peak distributions of chlorinated paraffins homologue groups in high resolution mass spectrometry in soft ionization modes2015Konferensbidrag (Övrigt vetenskapligt)
  • 853.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Benskin, Jonathan P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Chen, Chang-Er L.
    Bergman, Åke
    Determination of Chlorinated Paraffins by Bromide-Anion Attachment Atmospheric-Pressure Chemical Ionization Mass Spectrometry2018Ingår i: Environmental Science and Technology Letters, E-ISSN 2328-8930, Vol. 5, nr 6, s. 348-353Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel method for the quantitative determination of chlorinated paraffins (CPs) was developed using bromide-anion attachment atmospheric-pressure chemical ionization mass spectrometry (APCI-MS). Bromoform was used to enhance ionization of CPs. Near exclusive formation of stable bromide adduct ions ([M + BR](-)) enabled accurate detection of individual CP congener groups (CnClm) with only a moderate-resolution quadrupole time-of-flight mass spectrometer. Furthermore, the method was free from interference commonly observed with chloride-anion attachment methods (e.g., decomposition ions [M + Cl - HCl](-)) that require deconvolution. Together with a CnClm-response-factor algorithm for quantifying short-chain CPs and a CnClm-pattern-reconstruction algorithm for quantifying medium- and long-chain CPs, method applicability was demonstrated on biota and sediment samples. These data were generated significantly faster and with improved selectivity and sensitivity versus those of conventional measurements by chloride-anion attachment APCI-MS.

  • 854.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bogdal, Christian
    Berger, Urs
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Gebbink, Wouter A.
    Alsberg, Tomas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Quantifying Short-Chain Chlorinated Paraffin Congener Groups2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 18, s. 10633-10641Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Accurate quantification of short-chain chlorinated paraffins (SCCPs) poses an exceptional challenge to analytical chemists. SCCPs are complex mixtures of chlorinated alkanes with variable chain length and chlorination level; congeners with a fixed chain length (n) and number of chlorines (m) are referred to as a congener group CnClm Recently, we resolved individual CnClm by mathematically deconvolving soft ionization high-resolution mass spectra of SCCP mixtures. Here we extend the method to quantifying CnClm by introducing CnClm specific response factors (RFs) that are calculated from 17 SCCP chain-length standards with a single carbon chain length and variable chlorination level. The signal pattern of each standard is measured on APCI-QTOF-MS. RFs of each CnClm are obtained by pairwise optimization of the normal distribution's fit to the signal patterns of the 17 chain-length standards. The method was verified by quantifying SCCP technical mixtures and spiked environmental samples with accuracies of 82-123% and 76-109%, respectively. The absolute differences between calculated and manufacturer-reported chlorination degrees were 0.9 to 1.0%Cl for SCCP mixtures of 49-71%Cl. The quantification method has been replicated with ECNI magnetic sector MS and ECNI-Q:Orbitrap-MS. CnClm concentrations determined with the three instruments were highly correlated (R-2 > 0.90) with each other.

  • 855.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Brüchert, Volker
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    de Witt, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Temporal Trends of C-8-C-36 Chlorinated Paraffins in Swedish Coastal Sediment Cores over the Past 80 Years2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 24, s. 14199-14208Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Temporal trends of chlorinated paraffins (CPs) were analyzed in three sediment cores collected near different potential CP sources along the Swedish Baltic Sea coast. C-8-C-36 CPs were found in sediment dating back to the 1930s. The maximum CP concentrations found in proximity to a metropolitan sewage treatment plant, a wood related industrial area, and a steel factory were 48; 160, and 1400 ng/g d.w., respectively, in sediment sections dated from the early 1990s or the 2000s. The temporal trends agree with statistics on CP importation in Sweden or local industrial activities. MCCPs (C-14-C-17 CPs) and LCCPs (C->= 18 CPs) predominated, in most sediments with average percentage compositions of 47 +/- 20% and 37 +/- 20%, respectively. Concentrations of SCCPs in the three cores showed a decreasing trend in recent years. The temporal trends of MCCPs indicated that these are currently the predominant CPs in use. This study showed for the first time that LCCPs from C-18 to C-36, as well as C-8-C-17 CPs, are persistent in sediments over the last 30-80 years, indicating that CPs are persistent chemicals regaidless of alkane-chain lengths.

  • 856.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Chinese Academy of Sciences, China.
    Fu, Jianjie
    Wang, Yawei
    Jiang, Guibin
    Short-chain chlorinated paraffins in soil, paddy seeds (Oryza sativa) and snails (Ampullariidae) in an e-waste dismantling area in China: Homologue group pattern, spatial distribution and risk assessment2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 220, s. 608-615Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Short-chain chlorinated paraffins (SCCPs) in multi-environmental matrices are studied in Taizhou, Zhejiang Province, China, which is a notorious e-waste dismantling area. The investigated matrices consist of paddy field soil, paddy seeds (Oryza sativa, separated into hulls and rice unpolished) and apple snails (Ampullariidae, inhabiting the paddy fields). The sampling area covered a 65-km radius around the contamination center. C-10 and C-11 are the two predominant homologue groups in the area, accounting for about 35.7% and 33.0% of total SCCPs, respectively. SCCPs in snails and hulls are generally higher than in soil samples (30.4-530 ng/g dw), and SCCPs in hulls are approximate five times higher than in corresponding rice samples (4.90-55.1 ng/g dw). Homologue pattern analysis indicates that paddy seeds (both hull and rice) tend to accumulate relatively high volatile SCCP homologues, especially the ones with shorter carbon chain length, while snails tend to accumulate relatively high lipophilic homologues, especially the ones with more substituted chlorines. SCCPs in both paddy seeds and snails are linearly related to those in the soil. The e-waste dismantling area, which covers a radius of approximate 20 km, shows higher pollution levels for SCCPs according to their spatial distribution in four matrices. The preliminary assessment indicates that SCCP levels in local soils pose no significant ecological risk for soil dwelling organisms, but higher risks from dietary exposure of SCCPs are suspected for people living in e-waste dismantling area.

  • 857.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Muir, Derek
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Methods for trace analysis of short-, medium-, and long-chain chlorinated paraffins: Critical review and recommendations2019Ingår i: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 1074, s. 16-32Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Many methods for quantifying chlorinated paraffins (CPs) yield only a total concentration of the mixture as a single value. With appropriate analytical instrumentation and quantification methods, more reliable and detailed analysis can be performed by quantifying total concentrations of short-, medium-, and longchain CPs (SCCPs, MCCPs, and LCCPs), and in the current optimal situation by quantifying individual carbon-chlorine congener groups (CnClm). Sample extraction and clean-up methods for other persistent organochlorines that have been adapted for recovery of CPs must be applied prior to quantification with appropriate quality assurance and quality control to ensure applicability of the methods for SCCPs, MCCPs, and LCCPs. Part critical review, part tutorial, and part perspective, this paper provides practical guidance to analytical chemists who are interested in establishing a method for analysis of CPs in their lab facilities using commercial reference standards, or for expanding existing analysis of total CPs or SCCPs to analysis of SCCPs, MCCPs, and LCCPs, or to analysis of CnClm congener groups.

  • 858.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Strid, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Darnerud, Per Ola
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Nyström, Jessica
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Karolinska Institutet, Sweden.
    Chlorinated paraffins leaking from hand blenders can lead to significant human exposures2017Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 109, s. 73-80Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Background: Chlorinated paraffins (CPs, polychlorinated n-alkanes) are versatile, high-production-volume chemicals. A previous study indicated that hand blenders leak CPs into prepared food. & para;& para;Objectives: (1) to estimate exposure to CPs from hand blender use compared to background CP exposure from diet; (2) to assess the risk from human dietary exposure to CPs from hand blender use; (3) to investigate how hand blenders leak out CPs. & para;& para;Methods: CPs were analyzed in food market baskets, in cooking oil/water samples (1 g oil/100 mL water) mixed using 16 different hand blenders, and in dismantled components of the hand blenders. & para;& para;Results: Dietary intake of CPs from food market baskets was calculated to be 4.6 mu g/day per capita for Swedish adults. Total CP amounts in oil/water leakage samples ranged from < 0.09 to 120 mu g using the hand blenders once. CP leakage showed no decreasing levels after 20 times of hand blender usage. CP profiles in the leakage samples matched those of self-lubricating bearings and/or polymer components disassembled from the hand blenders. & para;& para;Conclusions: Usage of 75% of the hand blenders tested will lead to increased human exposure to CPs. The intake of CPs for Swedish adults by using hand blenders once a day can raise their daily dietary intake by a factor of up to 26. The 95th percentile intake of CPs via using the hand blenders once a day exceeded the TDI for Swedish infants with a body weight < 7.2 kg. CP leakage came from blender components which contain CPs. The leakage may last several hundred times of hand blender use.

  • 859.
    Yuan, Bo
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vorkamp, Katrin
    Roos, Anna Maria
    Faxneld, Suzanne
    Sonne, Christian
    Garbus, Svend Erik
    Lind, Ylva
    Eulaers, Igor
    Hellström, Peter
    Dietz, Rune
    Persson, Sara
    Bossi, Rossana
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Accumulation of Short-, Medium-, and Long-Chain Chlorinated Paraffins in Marine and Terrestrial Animals from Scandinavia2019Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, nr 7, s. 3526-3537Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Short-, medium-, and long-chain chlorinated paraffins (SCCPs, MCCPs, and LCCPs) have a wide range of physical-chemical properties, indicating their varying bioaccumulation tendencies in marine and terrestrial ecosystems. However, there are few empirical data to reveal such bioaccumulation tendencies. In this study, we analyzed SCCPs, MCCPs, and LCCPs in samples from 18 species at both low and high trophic levels of marine and terrestrial ecosystems from the Scandinavian region collected during the past decade. These included fish, seabirds, marine mammals, and terrestrial birds and mammals. SCCPs, MCCPs, and LCCPs were present in all the species, with concentrations ranging from 26-1500, 30-1600, 6.0-1200 ng/g lipid, respectively. Although MCCPs and SCCPs predominated in species, many terrestrial species had generally higher concentrations of LCCPs than marine species. Terrestrial raptors in particular accumulated higher concentrations of LCCPs, including C-24/25-which are predominant among very-long-chain components. LCCP concentrations were highest and predominated (55% of total CPs) in peregrine falcons in this study, which is the first report where concentrations of LCCPs surpass those of SCCPs and MCCPs in wildlife. The results also indicate biomagnification of SCCPs, MCCPs, and LCCPs in both marine and terrestrial food chains, but in-depth studies of specific food webs are needed.

  • 860.
    Zabaleta, Itsaso
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Bizkarguenaga, Ekhine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Izagirre, Urtzi
    Negreira, Noelia
    Covaci, Adrian
    Benskin, Jonathan P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Prieto, Ailette
    Zuloaga, Olatz
    Biotransformation of 8: 2 polyfluoroalkyl phosphate diester in gilthead bream (Sparus aurata)2017Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 609, s. 1085-1092Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polyfluoroalkyl phosphate esters (PAPs) are high production volume surfactants used in the food contact paper and packaging industry. PAPs may transform to persistent perfluoroalkyl carboxylic acids (PFCAs) under biotic conditions, but little is known about their fate and behavior in aquatic organisms. Here we report for the first time on the uptake, tissue distribution, and biotransformation of 8:2 polyfluoroalkyl phosphate diester (8:2 diPAP) in fish. Gilt-head bream (Sparus aurata) were dosed via the diet (8:2 diPAP at 29 mu g/g) for 7 days, during which time 8:2 diPAP and its transformation products were monitored in plasma, liver, muscle, gills, bile and brain. 8:2 diPAP tended to accumulate in liver, plasma and gills, and to a lesser extent in muscle, bile and brain. Several transformation products (observed previously in other organisms) were also observed inmost tissues and biofluids, including both saturated and unsaturated fluorotelomer acids (8:2 FTCA, 8:2 FTUCA, 7:3 FTCA), and perfluorooctanoic acid (PFOA). 8:2 FTCA was the major metabolite in all tissues/biofluids, except for bile, where PFOA occurred at the highest concentrations. Unexpectedly high PFOA levels (up to 3.7 ng/g) were also detected in brain. Phase 2 metabolites, which have been reported in fish following exposure to fluorotelomer alcohols, were not observed in these experiments, probably due to their low abundance. Nevertheless, the detection of PFOA indicates that exposure to PAPs may be an indirect route of exposure to PFCAs in fish.

  • 861.
    Zabaleta, Itsaso
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Bizkarguenaga, Ekhine
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Nunoo, Deborah B. O.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Schultes, Lara
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Leonel, Juliana
    Prieto, Ailette
    Zuloaga, Olatz
    Benskin, Jonathan P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Biodegradation and Uptake of the Pesticide Sulfluramid in a Soil-Carrot Mesocosm2018Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 52, nr 5, s. 2603-2611Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    N-ethyl perfluorooctane sulfonamide (EtFOSA) is the active ingredient of Sulfluramid, a pesticide which is used extensively in South America for control of leaf-cutting ants. Despite being a known precursor to perfluorooctanesulfonate (PFOS), the importance of EtFOSA as a source of environmental PFOS remains unclear. In the present work, uptake, leaching, and biodegradation of EtFOSA and its transformation products were assessed over 81 days in soil-carrot (Daucus carota ssp sativus) mesocosms for the first time. Experiments performed in the presence of carrot produced PFOS yields of up to 34% using a technical EtFOSA standard and up to 277% using Grao Forte, a commercial Sulfluramid bait formulation containing 0.0024% EtFOSA. Perfluorooctane sulfonamido acetate (FOSAA), perfluorooctane sulfonamide (FOSA), and perfluorooctanoic acid (PFOA) also formed over the course of the experiments, with the latter substance attributed to the presence of perfluorooctanamide impurities. The leachate contained low levels of transformation products and a high FOSA:PFOS ratio, consistent with recent observations in Brazilian surface water. In carrots, the more hydrophilic transformation products (e.g., PFOS) occurred primarily in the leaves, while the more hydrophobic products (e.g., FOSA, FOSAA, and EtFOSA) occurred in the peel and core. Remarkably, isomer-specific analysis revealed that the linear EtFOSA isomer biodegraded significantly faster than branched isomers. These data collectively show that the application of Sulfluramid baits can lead to the occurrence of PFOS in crops and in the surrounding environment, in considerably higher yields than previously thought.

  • 862.
    Zabori, Julia
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Rastak, Narges
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yoon, Y. J.
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ström, Johan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Size-resolved cloud condensation nuclei concentration measurements in the Arctic: two case studies from the summer of 20082015Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, nr 23, s. 13803-13817Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The Arctic is one of the most vulnerable regions affected by climate change. Extensive measurement data are needed to understand the atmospheric processes governing this vulnerability. Among these, data describing cloud formation potential are of particular interest, since the indirect effect of aerosols on the climate system is still poorly understood. In this paper we present, for the first time, size-resolved cloud condensation nuclei (CCN) data obtained in the Arctic. The measurements were conducted during two periods in the summer of 2008: one in June and one in August, at the Zeppelin research station (78 degrees 54'N, 11 degrees 53'E) in Svalbard. Trajectory analysis indicates that during the measurement period in June 2008, air masses predominantly originated from the Arctic, whereas the measurements from August 2008 were influenced by mid-latitude air masses. CCN supersaturation (SS) spectra obtained on the 27 June, before size-resolved measurements were begun, and spectra from the 21 and 24 August, conducted before and after the measurement period, revealed similarities between the 2 months. From the ratio between CCN concentration and the total particle number concentration (CN) as a function of dry particle diameter (D-p) at a SS of 0.4 %, the activation diameter (D-50), corresponding to CCN / CN = 0.50, was estimated. D-50 was found to be 60 and 67 nm for the examined periods in June and August 2008, respectively. Corresponding D-50 hygroscopicity parameter (kappa) values were estimated to be 0.4 and 0.3 for June and August 2008, respectively. These values can be compared to hygroscopicity values estimated from bulk chemical composition, where kappa was calculated to be 0.5 for both June and August 2008. While the agreement between the 2 months is reasonable, the difference in kappa between the different methods indicates a size dependence in the particle composition, which is likely explained by a higher fraction of inorganics in the bulk aerosol samples.

  • 863. Zamani, Leila
    et al.
    Lundqvist, Magnus
    Zhang, Ye
    Åberg, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Edfors, Fredrik
    Bidkhori, Gholamreza
    Lindahl, Anna
    Mie, Axel
    Mardinoglu, Adil
    Field, Raymond
    Turner, Richard
    Rockberg, Johan
    Chotteau, Veronique
    High Cell Density Perfusion Culture has a Maintained Exoproteome and Metabolome2018Ingår i: Biotechnology Journal, ISSN 1860-6768, E-ISSN 1860-7314, Vol. 13, nr 10, artikel-id 1800036Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The optimization of bioprocesses for biopharmaceutical manufacturing by Chinese hamster ovary (CHO) cells can be a challenging endeavor and, today, heavily relies on empirical methods treating the bioreactor process and the cells as black boxes. Multi-omics approaches have the potential to reveal otherwise unknown characteristics of these systems and identify culture parameters to more rationally optimize the cultivation process. Here, the authors have applied both metabolomic and proteomic profiling to a perfusion process, using CHO cells for antibody production, to explore how cell biology and reactor environment change as the cell density reaches 200x10(6)cellsmL(-1). The extracellular metabolic composition obtained in perfusion mode shows a markedly more stable profile in comparison to fed-batch, despite a far larger range of viable cell densities in perfusion. This stable profile is confirmed in the extracellular proteosome. Furthermore, the proteomics data shows an increase of structural proteins as cell density increases, which could be due to a higher shear stress and explain the decrease in cell diameter at very high cell densities. Both proteomic and metabolic results shows signs of oxidative stress and changes in glutathione metabolism at very high cell densities. The authors suggest the methodology presented herein to be a powerful tool for optimizing processes of recombinant protein production.

  • 864. Zanatta, M.
    et al.
    Gysel, M.
    Bukowiecki, N.
    Mueller, T.
    Weingartner, E.
    Areskoug, Hans
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Fiebig, M.
    Yttri, K. E.
    Mihalopoulos, N.
    Kouvarakis, G.
    Beddows, D.
    Harrison, R. M.
    Cavalli, F.
    Putaud, J. P.
    Spindler, G.
    Wiedensohler, A.
    Alastuey, A.
    Pandolfi, M.
    Sellegri, K.
    Swietlicki, E.
    Jaffrezo, J. L.
    Baltensperger, U.
    Laj, P.
    A European aerosol phenomenology-5: Climatology of black carbon optical properties at 9 regional background sites across Europe2016Ingår i: Atmospheric Environment, ISSN 1352-2310, E-ISSN 1873-2844, Vol. 145, s. 346-364Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A reliable assessment of the optical properties of atmospheric black carbon is of crucial importance for an accurate estimation of radiative forcing. In this study we investigated the spatio-temporal variability of the mass absorption cross-section (MAC) of atmospheric black carbon, defined as light absorption coefficient (sigma(ap)) divided by elemental carbon mass concentration (m(EC)). sigma(ap) and m(EC) have been monitored at supersites of the ACTRIS network for a minimum period of one year. The 9 rural background sites considered in this study cover southern Scandinavia, central Europe and the Mediterranean. sigma(ap) was determined using filter based absorption photometers and m(EC) using a thermal-optical technique. Homogeneity of the data-set was ensured by harmonization of all involved methods and instruments during extensive intercomparison exercises at the European Center for Aerosol Calibration (ECAC). Annual mean values of sigma(ap) at a wavelength of 637 nm vary between 0.66 and 1.3 Mm(-1) in southern Scandinavia, 3.7-11 Mm(-1) in Central Europe and the British Isles, and 2.3-2.8 Mm(-1) in the Mediterranean. Annual mean values of mEC vary between 0.084 and 0.23 mu g m(-3) in southern Scandinavia, 0.28 -1.1 in Central Europe and the British Isles, and 0.22-0.26 in the Mediterranean. Both sigma(ap) and mEC in southern Scandinavia and Central Europe have a distinct seasonality with maxima during the cold season and minima during summer, whereas at the Mediterranean sites an opposite trend was observed. Annual mean MAC values were quite similar across all sites and the seasonal variability was small at most sites. Consequently, a MAC value of 10.0 m(2) g(-1) (geometric standard deviation = 133) at a wavelength of 637 nm can be considered to be representative of the mixed boundary layer at European background sites, where BC is expected to be internally mixed to a large extent. The observed spatial variability is rather small compared to the variability of values in previous literature, indicating that the harmonization efforts resulted in substantially increased precision of the reported MAC. However, absolute uncertainties of the reported MAC values remain as high as +/- 30-70% due to the lack of appropriate reference methods and calibration materials. The mass ratio between elemental carbon and non-light-absorbing matter was used as a proxy for the thickness of coatings around the BC cores, in order to assess the influence of the mixing state on the MAC of BC. Indeed, the MAC was found to increase with increasing values of the coating thickness proxy. This provides evidence that coatings do increase the MAC of atmospheric BC to some extent, which is commonly referred to as lensing effect.

  • 865.
    Zguna, Nadezda
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mass-spectrometry based survey of BMAA sources, distribution and transfer2019Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    β-methylaminoalanine (BMAA) is a neurotoxic non-protein amino acid first isolated from cycad seeds in 1967. It is believed to be connected to neurodegenerative diseases such as Parkinson’s, Alzheimer’s and amyotrophic lateral sclerosis (ALS) and is a ubiquitous compound produced by cyanobacteria, diatoms and dinoflagellates. Consequently, elucidating natural production, distribution and routes for human exposure of BMAA are of particular importance. However, the natural function of BMAA and its mechanisms of toxicity have not been fully established yet. The contradictory results about BMAA presence in cyanobacterial cultures and food webs have been reported by different scientific groups, which required the development of more sensitive and reliable analytical methods. 

    This thesis is focused on the analytical chemistry dimension of BMAA research: covering both new method development and novel applications. New analytical methods for BMAA detection and quantification were developed, focusing on improving sensitivity, since BMAA is normally found in natural samples at low concentrations. In Paper I, a new derivatization technique was implemented, which increased sensitivity and selectivity in the analysis of BMAA and its isomers. Subsequently, this developed method was applied to determine the presence of BMAA in fat and oil matrices in Paper II, which is a step towards discovering BMAA forms other than the documented free and protein-bound BMAA species. In Paper III, a method for separation and quantification of L- and D-BMAA stereoisomers in complex biological matrix was developed and applied to determine the enantiomeric composition of BMAA in cycad seed. Studying environmental distribution of BMAA is important to evaluate potential exposure routes and health risks for humans. Part of the work was devoted to broaden assessment on environmental occurrence of BMAA by applying existing robust methodology to new samples, such as commercial seafood in Paper IV and Baltic Sea biota in Paper V. Some of the “overlooked” aspects in the existing BMAA literature (i.e., BMAA chiral analysis, possible BMAA presence in dietary oil supplements and defined food webs) were successfully addressed. 

    Overall, the thesis presents important analytical developments, which can help to further elucidate sources, distribution and transfer of BMAA.

  • 866.
    Zguna, Nadezda
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Holmbäck, Jan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ilag, Leopold
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Analysis of BMAA in fish oil and its vegan alternativesManuskript (preprint) (Övrigt vetenskapligt)
  • 867.
    Zguna, Nadezda
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlson, Agnes
    Ilag, Leopold
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Is there BMAA transfer in the pelagic and benthic food webs in the Baltic Sea?Manuskript (preprint) (Övrigt vetenskapligt)
  • 868.
    Zguna, Nadezda
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Karlson, Agnes M. L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för ekologi, miljö och botanik.
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Garbaras, Andrius
    Gorokhova, Elena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Insufficient evidence for BMAA transfer in the pelagic and benthic food webs in the Baltic Sea2019Ingår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, artikel-id 10406Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The evidence regarding BMAA occurrence in the Baltic Sea is contradictory, with benthic sources appearing to be more important than pelagic ones. The latter is counterintuitive considering that the identified sources of this compound in the food webs are pelagic primary producers, such as diatoms, dinoflagellates, and cyanobacteria. To elucidate BMAA distribution, we analyzed BMAA in the pelagic and benthic food webs in the Northern Baltic Proper. As potential sources, phytoplankton communities were used. Pelagic food chain was represented by zooplankton, mysids and zooplanktivorous fish, whereas benthic invertebrates and benthivorous fish comprised the benthic chain. The trophic structure of the system was confirmed by stable isotope analysis. Contrary to the reported ubiquitous occurrence of BMAA in the Baltic food webs, only phytoplankton, zooplankton and mysids tested positive, whereas no measurable levels of this compound occurred in the benthic invertebrates and any of the tested fish species. These findings do not support the widely assumed occurrence and transfer of BMAA to the top consumers in the Baltic food webs. More controlled experiments and field observations are needed to understand the transfer and possible transformation of BMAA in the food web under various environmental settings.

  • 869.
    Zguna, Nadezda
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Zurita, Javier
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andrýs, Rudolf
    Jiang, Liying
    Thorsén, Gunnar
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    LC-MS/MS for chiral separation of β-Methylamino-L-alanine (BMAA) enantiomers after (+)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) derivatizationManuskript (preprint) (Övrigt vetenskapligt)
  • 870. Zhang, Haiyan
    et al.
    Vestergren, Robin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. FRAM − High North Research Centre on Climate and the Environment, Norway.
    Wang, Thanh
    Yu, Junchao
    Jiang, Guibin
    Herzke, Dorte
    Geographical Differences in Dietary Exposure to Perfluoroalkyl Acids between Manufacturing and Application Regions in China2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 10, s. 5747-5755Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Emissions of perfluoroalkyl acids (PFAAs) have increased in China over the past decade, but human exposure pathways are poorly understood. Here we analyzed 15 PFAAs in commonly consumed food items and calculated body weight normalized dietary intake rates (estimated dietary intake, EDIs) in an area with ongoing PFAA production (Hubei province; n = 121) and an urbanized coastal area (Zhejiang province; n = 106). Geographical differences in concentrations were primarily observed for perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) in animal food items and short chain PFAAs in vegetable food items. The average EDI of Sigma PFAAs for adults in Hubei (998 ng kg(-1) day(-1)) was more than 2 orders of magnitude higher than that in Zhejiang (9.03 ng kg-1 day(-1)). In Hubei province, the average EDI of PFOS for adults (87 ng kg(-1) day(-1)) was close to or exceeded advisory guidelines used in other countries indicating health risks for the population from long-term exposure. Yet, PFOS could only account for about 10% of the EDI of Sigma PFAAs in the Hubei province, which was dominated by short-chain PFAAs through consumption of vegetables. The large contribution of short-chain PFAAs to the total EDIs in manufacturing areas emphasize the need for improved exposure and hazard assessment tools of these substances.

  • 871. Zhang, Jin
    et al.
    Kamstra, Jorke H.
    Ghorbanzadeh, Mehdi
    Weiss, Jana M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. VU University Amsterdam, The Netherlands.
    Hamers, Timo
    Andersson, Patrik L.
    In Silico Approach To Identify Potential Thyroid Hormone Disruptors among Currently Known Dust Contaminants and Their Metabolites2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 16, s. 10099-10107Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 872. Zhang, Shipeng
    et al.
    Wang, Minghuai
    Ghan, Steven J.
    Ding, Aijun
    Wang, Hailong
    Zhang, Kai
    Neubauer, David
    Lohmann, Ulrike
    Ferrachat, Sylvaine
    Takeamura, Toshihiko
    Gettelman, Andrew
    Morrison, Hugh
    Lee, Yunha
    Shindell, Drew T.
    Partridge, Daniel G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Oxford, UK.
    Stier, Philip
    Kipling, Zak
    Fu, Congbin
    On the characteristics of aerosol indirect effect based on dynamic regimes in global climate models2016Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 16, nr 5, s. 2765-2783Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 873. Zhang, Yanxu
    et al.
    Horowitz, Hannah
    Wang, Jiancheng
    Xie, Zhouqing
    Kuss, Joachim
    Sörensen, Anne L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    A Coupled Global Atmosphere-Ocean Model for Air-Sea Exchange of Mercury: Insights into Wet Deposition and Atmospheric Redox Chemistry2019Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 53, nr 9, s. 5052-5061Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Air-sea exchange of mercury (Hg) is the largest flux between Earth system reservoirs. Global models simulate air-sea exchange based either on an atmospheric or ocean model simulation and treat the other media as a boundary condition. Here we develop a new modeling capability (NJUCPL) that couples GEOS-Chem (atmospheric model) and MITgcm (ocean model) at the native hourly model time step. The coupled model is evaluated against high-frequency simultaneous measurements of elemental mercury (Hg-0) in both the atmosphere and surface ocean obtained during five published cruises in the Atlantic, Pacific, and Southern Oceans. Results indicate that the calculated global Hg net evasion flux is 12% higher for the online model than the offline model. We find that the coupled online model captures the spatial pattern of the observations; specifically, it improves the representation of peak seawater Hg-0 (Hg-aq(0)) concentration associated with enhanced precipitation in the intertropical convergence zone in both the Atlantic and the Pacific Oceans. We investigate the causes of the observed Hg-aq(0) peaks with two sensitivity simulations and show that the high Hg-aq(0) concentrations are associated with elevated convective cloud mass flux and bromine concentrations in the tropical upper troposphere. Observations of elevated Hg-aq(0) concentrations in the western tropical Pacific Ocean merit further study involving BrO vertical distribution and cloud resolving models.

  • 874. Zhong, Cheng
    et al.
    Li, Jiaying
    Flynn, Shannon L.
    Nesbø, Camilla L.
    Sun, Chenxing
    von Gunten, Konstantin
    Lanoil, Brian D.
    Goss, Greg G.
    Martin, Jonathan W.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Alberta, Canada.
    Alessi, Daniel S.
    Temporal Changes in Microbial Community Composition and Geochemistry in Flowback and Produced Water from the Duvernay Formation2019Ingår i: Acs Earth and Space Chemistry, ISSN 2472-3452, Vol. 3, nr 6, s. 1047-1057Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Microbial activity in flowback and produced water (FPW) may negatively influence shale oil and gas extraction. However, the impacts of using recycled produced water (RPW) for subsequent fracturing jobs are not well-understood. In this study, we compared time series of FPW samples from two horizontally fractured wells drilled into the Duvernay Formation in Alberta, Canada; well 1 used RPW in the makeup of the hydraulic fracturing fluid (HFF) whereas well 2 did not. 16S rRNA gene sequencing and live/dead cell enumeration were used to track microbial communities. Within 20 days of flowback, total dissolved solids in well 1 and well 2 increased from 5310 mg/L and 288 mg/L to over 150,000 mg/L, and FPW temperatures increased from 20 and 9 degrees C to 77 and 71 degrees C, respectively. Alkyl dimethyl benzyl ammonium chloride (biocide) in well 2 decreased from 25 mu g/L to below the detection limit of 0.5 mu g/L. Cellular biomass decreased from similar to 10(5) cells mL(-1) to less than the detection limit of 10(5) cells mL(-1) in both wells, and the community in the samples was initially diverse but rapidly shifted to become dominated by the sulfidogenic lineage Halanaerobium. Methanogens were detected at low relative abundance within archaea, with DNA concentrations in FPW after 20 days inadequate for sequencing. Comparing the two wells, the start time of Halanaerobium enrichment was considerably shortened in well 1 relative to well 2. Our results suggest that subsurface environmental parameters primarily drive the rapid enrichment of sulfidogenic and halotolerant bacteria and current recycling strategies can facilitate the growth of these bacteria, whereas biocide seems to be a less important factor in this shift.

  • 875.
    Zhou, Yihui
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tongji University, China.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Athanassiadis, Ioannis
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Wideqvist, Ulla
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bignert, Anders
    Qiu, Yanling
    Zhu, Zhiliang
    Zhao, Jianfu
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish Toxicology Sciences Research Center (Swetox), Sweden; Tongji University, China.
    Extensive organohalogen contamination in wildlife from a site in the Yangtze River Delta2016Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 554, s. 320-328Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 876.
    Zhou, Yihui
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tongji University, China.
    Chen, Qiaofeng
    Du, Xinyu
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Qiu, Yanling
    Ye, Lu
    Zhu, Zhiliang
    Zhao, Jianfu
    Occurrence and trophic magnification of polybrominated diphenyl ethers (PBDEs) and their methoxylated derivatives in freshwater fish from Dianshan Lake, Shanghai, China2016Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 219, s. 932-938Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 877. Zhou, Yihui
    et al.
    de Wit, Cynthia A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Shimadzu (China) Co. LTD., China.
    Du, Xinyu
    Yuan, Bo
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Shorter than short-chain: Very short-chain chlorinated paraffins (vSCCPs) found in wildlife from the Yangtze River Delta2019Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 130, artikel-id 104955Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Very short-chain chlorinated paraffins (vSCCPs, C6-9) occurred in 94% of wildlife samples from the Yangtze River Delta (YRD), China, with CnClm comparable to that of a local CP product, CP-52. Therefore, we determined the content of vSCCPs in CP-52 using a mathematical deconvolution technique. Then with CP-52 and several other reference standards, vSCCPs together with short-, medium-, and long-chain CPs were quantified in 21 wildlife species from an artificial wetland ecosystem and a freshwater ecosystem in the YRD. Concentrations of vSCCPs ranged from 2.6 to 8400 ng/g lipid. These concentrations were 1.2-380 fold lower than SCCPs, but were significantly correlated with those of SCCPs. vSCCP concentrations were comparable to or higher than reported for brominated flame retardants in the same samples. Bioaccumulation tendency of vSCCPs was identified in two benthic species, indicating congener-specific accumulation of vSCCPs in the environment.

  • 878.
    Zhou, Yihui
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tongji University, China.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Qiu, Yanling
    Bignert, Anders
    Zhu, Zhiliang
    Zhao, Jianfu
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Swedish Toxicology Sciences Research Center, Sweden; Tongji University, China.
    A novel pollution pattern: Highly chlorinated biphenyls retained in Black-crowned night heron (Nycticorax nycticorax) and Whiskered tern (Chlidonias hybrida) from the Yangtze River Delta2016Ingår i: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 150, s. 491-498Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 879.
    Zhou, Yihui
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Stewart, Kathryn
    Rantakokko, Panu
    Bignert, Anders
    Ruokojärvi, Päivi
    Kiviranta, Hannu
    Qiu, Yanling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ma, Zhijun
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    High concentrations of OCDD and related chemicals in heron and tern eggs from Yangtze River Delta indicating PCP originArtikel i tidskrift (Övrigt vetenskapligt)
  • 880.
    Zhou, Yihui
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tongji University, China.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Asplund, Lillemor
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Stewart, Kathryn
    Rantakokko, Panu
    Bignert, Anders
    Ruokojärvi, Päivi
    Kiviranta, Hannu
    Qiu, Yanling
    Ma, Zhijun
    Bergman, Åke
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. Tongji University, China; Karolinska Institute, Sweden.
    Human exposure to PCDDs and their precursors from heron and tern eggs in the Yangtze River Delta indicate PCP origin2017Ingår i: Environmental Pollution, ISSN 0269-7491, E-ISSN 1873-6424, Vol. 225, s. 184-192Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 881. Zhou, Yihui
    et al.
    Yin, Ge
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Du, Xinyu
    Xu, Maoying
    Qiu, Yanling
    Ahlqvist, Patrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Chen, Qiaofeng
    Zhao, Jianfu
    Short-chain chlorinated paraffins (SCCPs) in a freshwater food web from Dianshan Lake: Occurrence level, congener pattern and trophic transfer2018Ingår i: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 615, s. 1010-1018Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 882.
    Ziarrusta, Haizea
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Mijangos, Leire
    Izagirre, Urtzi
    Plassmann, Merle M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Benskin, Jonathan P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Anakabe, Eneritz
    Olivares, Maitane
    Zuloaga, Olatz
    Bioconcentration and Biotransformation of Amitriptyline in Gilt-Head Bream2017Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 51, nr 4, s. 2464-2471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 883.
    Ziarrusta, Haizea
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of the Basque Country (UPV/EHU), Spain.
    Ribbenstedt, Anton
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Mijangos, Leire
    Picart-Armada, Sergio
    Perera-Lluna, Alex
    Prieto, Ailette
    Izagirre, Urtzi
    Benskin, Jonathan P.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Olivares, Maitane
    Zuloaga, Olatz
    Etxebarria, Nestor
    Amitriptyline at an Environmentally Relevant Concentration Alters the Profile of Metabolites Beyond Monoamines in Gilt-Head Bream2019Ingår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 38, nr 5, s. 965-977Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The antidepressant amitriptyline is a widely used selective serotonin reuptake inhibitor that is found in the aquatic environment. The present study investigates alterations in the brain and the liver metabolome of gilt-head bream (Sparus aurata) after exposure at an environmentally relevant concentration (0.2 mu g/L) of amitriptyline for 7 d. Analysis of variance-simultaneous component analysis is used to identify metabolites that distinguish exposed from control animals. Overall, alterations in lipid metabolism suggest the occurrence of oxidative stress in both the brain and the liver-a common adverse effect of xenobiotics. However, alterations in the amino acid arginine are also observed. These are likely related to the nitric oxide system that is known to be associated with the mechanism of action of antidepressants. In addition, changes in asparagine and methionine levels in the brain and pantothenate, uric acid, and formylisoglutamine/N-formimino-L-glutamate levels in the liver could indicate variation of amino acid metabolism in both tissues; and the perturbation of glutamate in the liver implies that the energy metabolism is also affected. These results reveal that environmentally relevant concentrations of amitriptyline perturb a fraction of the metabolome that is not typically associated with antidepressant exposure in fish.

  • 884.
    Zieger, Paul
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Aalto, P. P.
    Aaltonen, V.
    Aijala, M.
    Backman, J.
    Hong, J.
    Komppula, M.
    Krejci, Radovan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi. University of Helsinki, Finland.
    Laborde, M.
    Lampilahti, J.
    de Leeuw, G.
    Pfuller, A.
    Rosati, B.
    Tesche, Matthias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Tunved, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vaananen, R.
    Petaja, T.
    Low hygroscopic scattering enhancement of boreal aerosol and the implications for a columnar optical closure study2015Ingår i: Atmospheric Chemistry And Physics, ISSN 1680-7316, E-ISSN 1680-7324, Vol. 15, nr 13, s. 7247-7267Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 885.
    Zieger, Paul
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Vaisanen, O.
    Corbin, J. C.
    Partridge, Dan G.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bastelberger, S.
    Mousavi-Fard, M.
    Rosati, B.
    Gysel, M.
    Krieger, U. K.
    Leck, Caroline
    Stockholms universitet, Naturvetenskapliga fakulteten, Meteorologiska institutionen (MISU).
    Nenes, A.
    Riipinen, Ilona
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Virtanen, A.
    Salter, Matthew E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Revising the hygroscopicity of inorganic sea salt particles2017Ingår i: Nature Communications, ISSN 2041-1723, E-ISSN 2041-1723, Vol. 8, artikel-id 15883Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 886.
    Zou, Hongyan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    The measurement of chemical persistence in the field by benchmarking: Theory and Experiment2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

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

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

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

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

  • 887.
    Zou, Hongyan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Radke, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kierkegaard, Amelie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    MacLeod, Matthew
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Using Chemical Benchmarking to Determine the Persistence of Chemicals in a Swedish Lake2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 3, s. 1646-1653Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 888.
    Zou, Hongyan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Radke, Michael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kierkegaard, Amelie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    McLachlan, Michael S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Temporal Variation of Chemical Persistence in a Swedish Lake Assessed by Benchmarking2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 16, s. 9881-9888Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 889.
    Zurita, Javier
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Amino acids with relevance to health, climate and the environment: Development of mass spectrometric methods2018Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

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

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

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

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

  • 890.
    Zurita, Javier
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Motwani, Hitesh V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Souliotos, Vassilis L
    Kyrtopoulos, Soterios A
    Nilsson, Ulrika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Törnqvist, Margareta
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Detection of benzo[a]pyrene diol epoxide adducts to histidine and lysine in serum albumin in vivo by high-resolution-tandem mass spectrometryManuskript (preprint) (Övrigt vetenskapligt)
  • 891.
    Zurita, Javier
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Zguna, Nadezda
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andrýs, Rudolf
    Strzelczak, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Jiang, Liying
    Thorsen, Gunnar
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Chiral separation of beta-Methylamino-alanine (BMAA) enantiomers after (+)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) derivatization and LC-MS/MS2019Ingår i: Analytical Methods, ISSN 1759-9660, E-ISSN 1759-9679, Vol. 11, s. 432-442Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    β-Methylamino-L-alanine, a neurotoxin first isolated from the seeds of cycad tree Cycas circinalis, is widely spread in a variety of environments. New sensitive techniques and robust methodologies are needed to detect its presence in complex biological samples and to further understand its biochemical properties. In this context, the determination of the enantiomeric composition of natural BMAA is of great importance. In this study, a simple and easily implemented LC-ESI-MS/MS method was developed to determine the presence of both D- and L-BMAA enantiomers in samples of cycad seed (Cycas micronesica). The samples were subjected to enzymatic hydrolysis to avoid racemization that occurs during strong acid hydrolysis. Derivatization with (+)-1-(9-fluorenyl)-ethyl chloroformate (FLEC) was performed prior to LC-ESI-MS/MS to produce chromatographically separable derivatives of D- and L-BMAA. Together with the retention time, two MRM transitions and their peak area ratios were used to identify the compounds. The LOQ obtained was 0.3 μg BMAA per g wet weight for each enantiomer. Method repeatability was within 3 RSD% both intraday and interday and accuracy was 98–108%. An accurate enantiomeric composition was obtained from the samples of cycad seed, where L- and D-BMAA were detected at 50.13 ± 0.05 and 4.08 ± 0.04 μg BMAA per g wet weight respectively (n = 3).

  • 892.
    Ågerstrand, Marlene
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    In Response: Reporting recommendations to ensure reliability and reproducibility of ecotoxicity studies—A tripartite initiative2016Ingår i: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 35, nr 5, s. 1072-1073Artikel i tidskrift (Övrigt vetenskapligt)
  • 893.
    Ågerstrand, Marlene
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Berg, Cecilia
    Björlenius, Berndt
    Breitholtz, Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Brunström, Björn
    Fick, Jerker
    Gunnarsson, Lina
    Larsson, D. G. Joakim
    Sumpter, John P.
    Tysklind, Mats
    Rudén, Christina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Improving Environmental Risk Assessment of Human Pharmaceuticals2015Ingår i: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 49, nr 9, s. 5336-5345Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 894.
    Ågerstrand, Marlene
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Beronius, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Weight of evidence evaluation and systematic review in EU chemical risk assessment: Foundation is laid but guidance is needed2016Ingår i: Environment International, ISSN 0160-4120, E-ISSN 1873-6750, Vol. 92-93, s. 590-596Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

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

  • 895.
    Ågerstrand, Marlene
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Brenig, Mattheus
    Führ, Martin
    Schenten, Julian
    Refining tools to bridge the gap between academia and chemical regulation: perspectives for WikiREACH2017Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, nr 12, s. 1466-1473Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

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

  • 896.
    Ågerstrand, Marlene
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Christiansen, Sofie
    Hanberg, Annika
    Rudén, Christina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Andersson, Lars
    Andersen, Sjur
    Appelgren, Henrik
    Bjørge, Christine
    Clausen, Ian Henning
    Eide, Dag Markus
    Hartmann, Nanna B.
    Husøy, Trine
    Halldórsson, Halldór Pálmar
    van der Hagen, Marianne
    Ingre-Khans, Ellen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lillicrap, Adam David
    Beltoft, Vibe Meister
    Mörk, Anna-Karin
    Murtomaa-Hautala, Mari
    Nielsen, Elsa
    Ólafsdóttir, Kristín
    Palomäki, Jaana
    Papponen, Hinni
    Reiler, Emilie Marie
    Stockmann-Juvala, Helene
    Suutari, Tiina
    Tyle, Henrik
    Beronius, Anna
    A call for action: Improve reporting of research studies to increase the scientific basis for regulatory decision-making2018Ingår i: Journal of Applied Toxicology, ISSN 0260-437X, E-ISSN 1099-1263, Vol. 38, nr 5, s. 783-785Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 897.
    Ågerstrand, Marlene
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobek, Anna
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Lilja, Karl
    Linderoth, Maria
    Wendt-Rasch, Lina
    Wernersson, Ann-Sofie
    Rudén, Christina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    An academic researcher's guide to increased impact on regulatory assessment of chemicals2017Ingår i: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 19, nr 5, s. 644-655Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 898. Åkerblom, Staffan
    et al.
    Meili, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Bishop, Kevin
    Organic Matter in Rain: An Overlooked Influence on Mercury Deposition2015Ingår i: Environmental Science and Technology Letters, E-ISSN 2328-8930, Vol. 2, nr 4, s. 128-132Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 899.
    Österlund, Nicklas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kulkarni, Yashraj S.
    Misiaszek, Agata D.
    Wallin, Cecilia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Krüger, Dennis M.
    Liao, Qinghua
    Mashayekhy Rad, Farshid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Jarvet, Jüri
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Strodel, Birgit
    Wärmländer, Sebastian K. T. S.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Kamerlin, Shina C. L.
    Gräslund, Astrid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Amyloid-beta Peptide Interactions with Amphiphilic Surfactants: Electrostatic and Hydrophobic Effects2018Ingår i: ACS Chemical Neuroscience, ISSN 1948-7193, E-ISSN 1948-7193, Vol. 9, nr 7, s. 1680-1692Artikel i tidskrift (Refereegranskat)
    Abstract [en]

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

  • 900.
    Österlund, Nicklas
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Moons, Rani
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för miljövetenskap och analytisk kemi.
    Sobott, Frank
    Gräslund, Astrid
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för biokemi och biofysik.
    Native Ion Mobility-Mass Spectrometry Reveals the Formation of beta-Barrel Shaped Amyloid-beta Hexamers in a Membrane-Mimicking Environment2019Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 141, nr 26, s. 10440-10450Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The mechanisms behind the Amyloid-beta (A beta) peptide neurotoxicity in Alzheimer's disease are intensely studied and under debate. One suggested mechanism is that the peptides assemble in biological membranes to form beta-barrel shaped oligomeric pores that induce cell leakage. Direct detection of such putative assemblies and their exact oligomeric states is however complicated by a high level of heterogeneity. The theory consequently remains controversial, and the actual formation of pore structures is disputed. We herein overcome the heterogeneity problem by employing a native mass spectrometry approach and demonstrate that A beta(1-42) peptides form coclusters with membrane mimetic detergent micelles. The coclusters are gently ionized using nanoelectrospray and transferred into the mass spectrometer where the detergent molecules are stripped away using collisional activation. We show that A beta(1-42) indeed oligomerizes over time in the micellar environment, forming hexamers with collision cross sections in agreement with a general beta-barrel structure. We also show that such oligomers are maintained and even stabilized by addition of lipids. A beta(1-40) on the other hand form significantly lower amounts of oligomers, which are also of lower oligomeric state compared to A beta(1-42) oligomers. Our results thus support the oligomeric pore hypothesis as one important cell toxicity mechanism in Alzheimer's disease. The presented native mass spectrometry approach is a promising way to study such potentially very neurotoxic species and how they could be stabilized or destabilized by molecules of cellular or therapeutic relevance.

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