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  • 201.
    Arnoldsson, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Formation of environmentally relevant brominated dioxins from 2,4,6,-tribromophenol via bromoperoxidase-catalyzed dimerization2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 13, p. 7239-7244Article in journal (Refereed)
    Abstract [en]

    Polybrominated dibenzo-p-dioxins (PBDD) are emerging environmental pollutants with structural similarities to the highly characterized toxicants polychlorinated dibenzo-p-dioxins. The geographical and temporal variations of PBDD in biota samples from the Baltic Sea do not display features that are normally related to anthropogenic sources such as incineration, and therefore the natural formation of PBDDs has been suggested. This study of the bromoperoxidase mediated oxidative coupling of 2,4,6-tribromophenol (an abundant substance that is naturally formed in marine systems) identified the formation of ppb-level yields of 1,3,6,8-tetrabromodibenzo-p-dioxin (1,3,6,8-TeBDD) through direct condensation. Additional TeBDDs (1,3,7,9-TeBDD, 1,2,4,7-TeBDD and/or 1,2,4,8-TeBDD) and tri-BDDs (1,3,7-TrBDD and 1,3,8-TrBDD) were frequently formed, but at lower yields. The formation of these TeBDDs probably proceeds via bromine shifts or Smiles rearrangements, while the TrBDDs may result from subsequent debromination processes. Since all of the congeners formed by oxidative coupling and subsequent reactions are also found in Baltic Sea biota, the results support the theory that PBDDs are formed from natural precursors.

  • 202.
    Arnoldsson, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Photochemical formation of polybrominated dibenzo-p-dioxins from environmentally abundant hydroxylated polybrominated diphenyl ethers2012In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 46, no 14, p. 7567-7574Article in journal (Refereed)
    Abstract [en]

    High levels of polybrominated dibenzo-p-dioxins (PBDDs) have been found in Baltic Sea biota, where the toxic load owing to, for example, polychlorinated dibenzo-p-dioxins and other organic pollutants is already high. The levels and geographic pattern of PBDDs suggest biogenic rather than anthropogenic origin, and both biotic and abiotic formation pathways have been proposed. Photochemical formation from hydroxylated polybrominated diphenyl ethers (OH-PBDE) is a proposed pathway. for PBDDs in marine environments. Ultraviolet radiation-initiated transformations of OH-BDEs 47, 68, 85, 90, 99, and 123, which all are abundant in the environment, were investigated. It was shown that the most abundant PBDDs in the environment (1,3,7-triBDD and 1,3,8-triBDD) can be formed from the most abundant OH-BDEs (OH-BDE 47 and OH-BDE 68) at high rates and with percentage yields. In fact, most of the PBDDs that have been identified in the Baltic Sea environment were formed with high yield from the six studied OH-PBDE, through initial cyclization and subsequent debromination reactions. The high formation yields point to this route as an important source of PBDDs in biota. However, congeners showing relatively high retention in fish, specifically 1,3,6,8- and 1,3,7,9-tetraBDD, were not formed. These are likely formed by enzymatic coupling of brominated phenols.

  • 203.
    Arnoldsson, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Norman Haldén, Anna
    Institutionen för biomedicin och veterinär folkhälsovetenskap, Sveriges Lantbruksuniversitet.
    Norrgren, Leif
    Institutionen för biomedicin och veterinär folkhälsovetenskap, Sveriges Lantbruksuniversitet.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Retention and maternal transfer of environmentally relevant polybrominated dibenzo-p-dioxins and dibenzofurans, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in zebrafish (Danio rerio) after dietary exposure2012In: Environmental Toxicology and Chemistry, ISSN 0730-7268, E-ISSN 1552-8618, Vol. 31, no 4, p. 804-812Article in journal (Refereed)
    Abstract [en]

    High levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), mono- and non-ortho polychlorinated biphenyls (PCBs), and polybrominated dibenzo-p-dioxins (PBDDs) are found in fish from coastal areas in the Baltic Sea, which may cause ecotoxicological effects. To increase our understanding of the persistency of the emerging pollutants polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), fish feed was spiked with 21 PBDD/Fs, 17 PCDD/Fs, and 30 PCBs and fed to zebrafish. Concentrations in fish and eggs were examined during a six- or twelve-week uptake period, and a six-week elimination period. Steady-state was reached for 2, 3, 7, and/or 8-substituted tri- and tetra-BDD/Fs, with 2,3,7,8-tetra-BDD (2,3,7,8-TeBDD) being the most strongly retained. Steady-state was not reached for tetra- to hexa-CDDs. Non-2,3,7,8-congeners showed little of or no retention. Most PCBs had high retention and did not reach steady-state. Half-lives decreased in the order: PCBs > PCDD/Fs > PBDD/Fs. Concentrations of 2,3,7,8-penta- to octa-CDD/Fs decreased with their degree of chlorination suggesting that the rate-limiting factor for uptake is low bioavailability. Maternal transfer was observed for all retained compounds, with most transfer factors < 1, indicating that transfer rates are affected by the poor water solubility of the compounds. The limited retention of the major PBDD congeners found in Baltic Sea fish suggests that they are exposed to high or very high concentrations via either food or water.

  • 204.
    Arnoldsson, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Norman Haldén, L
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Retention and maternal transfer of polybrominated dibenzo-p-dioxins and dibenzofurans, polychlorinated dibenzo-p-dioxins and dibenzofurans, and polychlorinated biphenyls in zebrafish (DANIO RERIO) 2010Conference paper (Refereed)
  • 205. Arp, Hans Peter H.
    et al.
    Lundstedt, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Josefsson, Sarah
    Cornelissen, Gerard
    Enell, Anja
    Allard, Ann-Sofie
    Kleja, Dan Berggren
    Native Oxy-PAHs, N-PACs, and PAHs in historically contaminated soils from Sweden, Belgium, and France: their soil-porewater partitioning behavior, bioaccumulation in Enchytraeus crypticus, and bioavailability2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 19, p. 11187-11195Article in journal (Refereed)
    Abstract [en]

    Soil quality standards are based on partitioning and toxicity data for laboratory-spiked reference soils, instead of real world, historically contaminated soils, which would be more representative. Here 21 diverse historically contaminated soils from Sweden, Belgium, and France were obtained, and the soil-porewater partitioning along with the bioaccumulation in exposed worms (Enchytraeus crypticus) of native polycyclic aromatic compounds (PACs) were quantified. The native PACs investigated were polycyclic aromatic hydrocarbons (PAHs) and, for the first time to be included in such a study, oxygenated-PAHs (oxy-PAHs) and nitrogen containing heterocyclic PACs (N-PACs). The passive sampler polyoxymethylene (POM) was used to measure the equilibrium freely dissolved porewater concentration, C-pw, of all PACs. The obtained organic carbon normalized partitioning coefficients, K-TOC, show that sorption of these native PACs is much stronger than observed in laboratory-spiked soils (typically by factors 10 to 100), which has been reported previously for PAHs but here for the first time for oxy-PAHs and N-PACs. A recently developed K-TOC model for historically contaminated sediments predicted the 597 unique, native K-TOC values in this study within a factor 30 for 100% of the data and a factor 3 for 58% of the data, without calibration. This model assumes that TOC in pyrogenic-impacted areas sorbs similarly to coal tar, rather than octanol as typically assumed. Black carbon (BC) inclusive partitioning models exhibited substantially poorer performance. Regarding bioaccumulation, C-pw combined with liposome-water partition coefficients corresponded better with measured worm lipid concentrations, C-lipid (within a factor 10 for 85% of all PACs and soils), than C-pw combined with octanol-water partition coefficients (within a factor 10 for 76% of all PACs and soils). E. crypticus mortality and reproducibility were also quantified. No enhanced mortality was observed in the 21 historically contaminated soils despite expectations from PAH spiked reference soils. Worm reproducibility weakly correlated to C-lipid of PACs, though the contributing influence of metal concentrations and soil texture could not be taken into account. The good agreement of POM-derived C-pw with independent soil and lipid partitioning models further supports that soil risk assessments would improve by accounting for bioavailability. Strategies for including bioavailability in soil risk assessment are presented.

  • 206. Arp, Hans Peter H
    et al.
    Møskeland, Thomas
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nyholm, Jenny Rattfelt
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Presence and partitioning properties of the flame retardants pentabromotoluene, pentabromoethylbenzene and hexabromobenzene near suspected source zones in Norway2011In: Journal of Environmental Monitoring, ISSN 1464-0325, E-ISSN 1464-0333, Vol. 13, no 3, p. 505-513Article in journal (Refereed)
    Abstract [en]

    The brominated flame retardants (BFRs), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB) and hexabromobenzene (HBB), exhibit physical-chemical properties similar to other persistent organic pollutants, and have been in use as flame retardants for several decades. Data on these BFRs in diverse environmental samples can be found in studies from the 1970s and 1980s, as well as in recent years, though very little in the years in between. Due to a lack of data, the cause for the apparent re-emergence of these BFRs in recent studies is unclear, and could reflect changes in production volumes, accumulation of transformation products from BFR precursors, improved analytical techniques or simply a re-emergence in concern. Very little data are available on their environmentally relevant partitioning properties, which could help to explain the occurrence and fate of these BFRs. In this study we analysed for the presence of HBB, PBT, and PBEB in diverse environmental samples from potential Norwegian BFR source zones. Additionally, environmental partitioning properties of these BFRs as well as brominated benzenes were estimated and validated using experimental data for brominated benzenes. Of the three BFRs, HBB was identified in detectable quantities at most source zones, PBEB only near a metal recycling factory, and PBT only in a few additional locations from where PBEB was detected. Data from this study show that HBB is likely widely distributed, as verified both by chemical analysis and estimated properties. Measured HBB levels in wastewater treatment plants indicate that the treatment practices used in the study locations are not effective at lowering HBB levels, perhaps due to association with low density suspended solids (e.g. microplastics).

  • 207. Arshadi, Mehrdad
    et al.
    Nilsson, Calle
    Magnusson, Bengt
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gas chromatography-mass spectrometry determination of the pentafluorobenzoyl derivative of methylhydrazine in false morel (Gyromitra esculenta) as a monitor for the content of the toxin gyromitrin2006In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1125, no 2, p. 229-233Article in journal (Refereed)
    Abstract [en]

    The main toxic compound found in false morel (Gyromitra esculenta) is acetaldehyde-N-methyl-N-formylhydrazone (gyromitrin). This paper describes a method of determining the total hydrazones content based on acid hydrolysis of gyromitrin and other related hydrazones in air-dried false morel followed by derivatisation of methylhydrazine with pentafluorobenzoyl chloride. The derivative, tris-pentafluorobenzoyl methylhydrazine (tris-PFB-MH) is analyzed by gas chromatography–mass spectrometry. The overall precision of the method is better than 10% (relative standard deviation) for 0.5 ng/μl methylhydrazine in solution. The minimum detectable concentration of methylhydrazine (tris-PFB-MH) by this method is estimated to be approximately 12 pg/μl, which is equal to 0.3 μg/g dry matter (DM) of false morel.

  • 208.
    Artursson, Elisabet
    et al.
    Swedish Defence Research Agency, CBRN, Defence and Security, Umeå.
    Andersson, Per Ola
    Swedish Defence Research Agency, CBRN, Defence and Security, Umeå.
    Akfur, Christine
    Swedish Defence Research Agency, CBRN, Defence and Security, Umeå.
    Linusson, Anna
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Börjegren, Susanne
    Swedish Defence Research Agency, CBRN, Defence and Security, Umeå.
    Ekström, Fredrik
    Swedish Defence Research Agency, CBRN, Defence and Security, Umeå.
    Catalytic-site conformational equilibrium in nerve-agent adducts of acetylcholinesterase: Possible implications for the HI-6 antidote substrate specificity2013In: Biochemical Pharmacology, ISSN 0006-2952, E-ISSN 1356-1839, Vol. 85, no 9, p. 1389-1397Article in journal (Refereed)
    Abstract [en]

    Nerve agents such as tabun, cyclosarin and Russian VX inhibit the essential enzyme acetylcholinesterase (AChE) by organophosphorylating the catalytic serine residue. Nucleophiles, such as oximes, are used as antidotes as they can reactivate and restore the function of the inhibited enzyme. The oxime HI-6 shows a notably low activity on tabun adducts but can effectively reactivate adducts of cyclosarin and Russian VX. To examine the structural basis for the pronounced substrate specificity of HI-6, we determined the binary crystal structures of Mus musculus AChE (mAChE) conjugated by cyclosarin and Russian VX and found a conformational mobility of the side chains of Phe338 and His447. The interaction between HI-6 and tabun-adducts of AChE were subsequently investigated using a combination of time resolved fluorescence spectroscopy and X-ray crystallography. Our findings show that HI-6 binds to tabun inhibited Homo sapiens AChE (hAChE) with an IC50 value of 300 μM and suggest that the reactive nucleophilic moiety of HI-6 is excluded from the phosphorus atom of tabun. We propose that a conformational mobility of the side-chains of Phe338 and His447 is a common feature in nerve-agent adducts of AChE. We also suggest that the conformational mobility allow HI-6 to reactivate conjugates of cyclosarin and Russian VX while a reduced mobility in tabun conjugated AChE results in steric hindrance that prevents efficient reactivation.

  • 209. Artursson, Tom
    et al.
    Eklöv, Tomas
    Lundström, Ingemar
    Mårtensson, Per
    Sjöström, Michael
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Holmberg, Martin
    Drift correction for gas sensors using multivariate methods2000In: Journal of Chemometrics, Vol. 14, no 5-6, p. 711-23Article in journal (Refereed)
    Abstract [en]

    Drift is one of the most serious impairments afflicting gas sensors. It can be seen as a gradual change in the sensor response over a long period of time when the external conditions are constant. This paper presents a new simple drift counteraction method based on PCA and PLS. The basic idea is to remove the drift direction component from the measurements. The direction of the drift, p, is calculated from measurements for a reference gas. Projecting the sample gas measurements on this vector gives the score vector t. The drift component tp T can then be removed from the sample gas data, which we call component correction (CC). The method is tested on a data set based on a reduced factorial design with four gases and a concentration gradient of hydrogen. It is found that the method works efficiently for both cases.

  • 210. Artursson, Tom
    et al.
    Hagman, Anders
    Björk, Seth
    Trygg, Johan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wold, Svante
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jacobsson, Sven P
    Study of Preprocessing Methods for the Determination of Crystalline Phases in Binary Mixtures of Drug Substances by X-ray Powder Diffraction and Multivariate Calibration2000In: Applied Spectroscopy, ISSN 0003-7028, E-ISSN 1943-3530, Vol. 54, no 8, p. 272A-301AArticle in journal (Refereed)
    Abstract [en]

    In this paper, various preprocessing methods were tested on data generated by X-ray powder diffraction (XRPD) in order to enhance the partial least-squares (PLS) regression modeling performance. The preprocessing methods examined were 22 different discrete wavelet transforms, Fourier transform, Savitzky-Golay, orthogonal signal correction (OSC), and combinations of wavelet transform and OSC, and Fourier transform and OSC. Root mean square error of prediction (RMSEP) of an independent test set was used to measure the performance of the various preprocessing methods. The best PLS model was obtained with a wavelet transform (Symmlet 8), which at the same time compressed the data set by a factor of 9.5. With the use of wavelet and X-ray powder diffraction, concentrations of less than 10% of one crystal from could be detected in a binary mixture. The linear range was found to be in the range 10-70% of the crystalline form of phenacetin, although semiquantitative work could be carried out down to a level of approximately 2%. Furthermore, the wavelet-pretreated models were able to handle admixtures and deliberately added noise.

  • 211.
    Arvidsson, Louise
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sexuella biverkningar vid behandling med antidepressiva läkemedel: Prevalens, patomekanismer och behandlingsmöjligheter. En litteraturstudie2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 212. Asgari, Parham
    et al.
    Hua, Yuanda
    Bokka, Apparao
    Thiamsiri, Chanachon
    Prasitwatcharakorn, Watcharapon
    Karedath, Ashif
    Chen, Xin
    Sardar, Sinjinee
    Yum, Kyungsuk
    Leem, Gyu
    Pierce, Brad S.
    Nam, Kwangho
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Gao, Jiali
    Jeon, Junha
    Catalytic hydrogen atom transfer from hydrosilanes to vinylarenes for hydrosilylation and polymerization2019In: Nature Catalysis, ISSN 2520-1158, Vol. 2, no 2, p. 164-173Article in journal (Refereed)
    Abstract [en]

    Because of the importance of hydrogen atom transfer (HAT) in biology and chemistry, there is increased interest in new strategies to perform HAT in a sustainable manner. Here, we describe a sustainable, net redox-neutral HAT process involving hydrosilanes and alkali metal Lewis base catalysts-eliminating the use of transition metal catalysts-and report an associated mechanism concerning Lewis base-catalysed, complexation-induced HAT. The catalytic Lewis base-catalysed, complexation-induced HAT is capable of accessing both branch-specific hydrosilylation and polymerization of vinylarenes in a highly selective fashion, depending on the Lewis base catalyst used. In this process, the Earth-abundant, alkali metal Lewis base catalyst plays a dual role. It first serves as a HAT initiator and subsequently functions as a silyl radical stabilizing group, which is critical to highly selective cross-radical coupling. An electron paramagnetic resonance study identified a potassiated paramagnetic species, and multistate density functional theory revealed a high HAT character, yet multiconfigurational nature in the transition state of the reaction.

  • 213.
    Asplund, Lena
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Den legitimerade farmaceutens yrkesroll på svenska apotek: En litteraturstudie av professionens betydelse i nutid och framtid2013Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 214. Asres, Georgies Alene
    et al.
    Baldoví, José J.
    Dombovari, Aron
    Järvinen, Topias
    Lorite, Gabriela Simone
    Mohl, Melinda
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Pérez Paz, Alejandro
    Xian, Lede
    Mikkola, Jyri-Pekka
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Industrial Chemistry & Reaction Engineering, Department of Chemical Engineering, Johan Gadolin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Spetz, Anita Lloyd
    Jantunen, Heli
    Rubio, Ángel
    Kordás, Krisztian
    Ultrasensitive H2S gas sensors based on p-type WS2 hybrid materials2018In: Nano Reseach, ISSN 1998-0124, E-ISSN 1998-0000, Vol. 11, no 8, p. 4215-4224Article in journal (Refereed)
    Abstract [en]

    Owing to their higher intrinsic electrical conductivity and chemical stability with respect to their oxide counterparts, nanostructured metal sulfides are expected to revive materials for resistive chemical sensor applications. Herein, we explore the gas sensing behavior of WS2 nanowire-nanoflake hybrid materials and demonstrate their excellent sensitivity (0.043 ppm-1) as well as high selectivity towards H2S relative to CO, NH3, H2, and NO (with corresponding sensitivities of 0.002, 0.0074, 0.0002, and 0.0046 ppm-1, respectively). Gas response measurements, complemented with the results of X-ray photoelectron spectroscopy analysis and first-principles calculations based on density functional theory, suggest that the intrinsic electronic properties of pristine WS2 alone are not sufficient to explain the observed high sensitivity towards H2S. A major role in this behavior is also played by O doping in the S sites of the WS2 lattice. The results of the present study open up new avenues for the use of transition metal disulfide nanomaterials as effective alternatives to metal oxides in future applications for industrial process control, security, and health and environmental safety.

  • 215.
    Assefa, Anteneh
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tracing and apportioning sources of dioxins using multivariate pattern recognition techniques2015Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    High levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) in edible fish in the Baltic Sea have raised health concerns in the Baltic region and the rest of Europe. Thus, there are urgent needs to characterize sources in order to formulate effective mitigation strategies. The aim of this thesis is to contribute to a better understanding of past and present sources of PCDD/Fs in the Baltic Sea environment by exploring chemical fingerprints in sediments, air, and biota. The spatial and temporal patterns of PCDD/F distributions in the Baltic Sea during the 20th century were studied in Swedish coastal and offshore sediment cores. The results showed that PCDD/F levels peaked in 1975 (± 7 years) in coastal and 1991 (± 5 years) in offshore areas. The time trends of PCDD/Fs in the sediment cores also showed that environmental half-lives of these pollutants have been shorter in coastal than in offshore areas (15 ± 5 and 29 ± 14 years, respectively). Consequently, there have been remarkable recoveries in coastal areas, but slower recovery in offshore areas with 81 ± 12% and 38 ± 11% reductions from peak levels, respectively.

    Source-to-receptor multivariate modeling by Positive Matrix Factorization (PMF) showed that six types of PCDD/F sources are and have been important for the Baltic Sea environment: PCDD/Fs related to i) atmospheric background, ii) thermal processes, iii) manufacture and use of tetra-chlorophenol (TCP) and iv) penta-chlorophenol (PCP), v) industrial use of elementary chlo- rine and the chloralkali-process (Chl), and vi) hexa-CDD sources. The results showed that diffuse sources (i and ii) have consistently contributed >80% of the total amounts in the Southern Baltic Sea. In the Northern Baltic Sea, where the biota is most heavily contaminated, impacts of local sources (TCP, PCP and Chl) have been higher, contributing ca. 50% of total amounts. Among the six sources, only Thermal and chlorophenols (ii-iv) have had major impacts on biota. The impact of thermal sources has, however, been declining as shown from source apportioned time-trend data of PCDD/Fs in Baltic herring. In contrast, impacts of chlorophenol-associated sources generally increased, remained at steady-state or slowly decreased during 1990-2010, suggesting that these sources have substantially contributed to the persistently high levels of PCDD/Fs in Baltic biota.

    Atmospheric sources of PCDD/Fs for the Baltic region (Northern Europe) were also investigated, and specifically whether the inclusion of parallel measurements of metals in the analysis of air would help back-tracking sources. PCDD/Fs and metals in high-volume air samples from a rural field station near the shore of the central Baltic Sea were measured. The study focused on the winter season and air from the S and E sectors, as these samples showed elevated levels of PCDD/Fs, particularly PCDFs. Several metals were found to correlate significantly with the PCDFs. The wide range of candidate metals as source markers for PCDD/F emissions, and the lack of an up-to-date extensive compilation of source characteristics for metal emission from vari- ous sources, limited the use of the metals as source markers. The study was not able to pin-point primary PCDD/F sources for Baltic air, but it demonstrated a new promising approach for source tracing of air emissions. The best leads for back-tracking primary sources of atmospheric PCDD/Fs in Baltic air were seasonal trends and PCDD/F congener patterns, pointing at non-industrial related thermal sources related to heating. The non-localized natures of the sources raise challenges for managing the emissions and thus societal efforts are required to better control atmospheric emissions of PCDD/Fs.

  • 216.
    Assefa, Anteneh Taye
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sobek, Anna
    Sundqvist, Kristina L.
    Cato, Ingemar
    Jonsson, Per
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wiberg, Karin
    Temporal Trends of PCDD/Fs in Baltic Sea Sediment Cores Covering the 20th Century2014In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 48, no 2, p. 947-953Article in journal (Refereed)
    Abstract [en]

    The pollution trend of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea region was studied based on depth profiles of PCDD/Fs in sediment cores collected from six offshore areas, eight coastal sites impacted by industrial/urban emissions, and one coastal reference site. A general trend was observed for the offshore and coastal reference sites with substantial increase in PCDD/F concentrations in the mid-late 1970s and peak levels during 1985-2002. The overall peak year for PCDD/Fs in Baltic Sea offshore areas was estimated (using spline-fit modeling) to 1994 ± 5 years, and a half-life in sediments was estimated at 29 ± 11 years. For the industrial/urban impacted coastal sites, the temporal trend was more variable with peak years occurring 1-2 decades earlier compared to offshore areas. The substantial reductions from peak levels (38 ± 11% and 81 ± 12% in offshore and coastal areas, respectively) reflect domestic and international actions taken for reduction of the release of PCDD/Fs to the environment. The modeled overall half-life and reductions of PCDD/Fs in offshore Baltic Sea sediment correspond well to both PCDD/F trends in European lakes without any known direct PCDD/F sources (half-lives 30 and 32 years), and previously modeled reduction in atmospheric deposition of PCDD/Fs to the Baltic Sea since 1990. These observations support previous findings of a common diffuse source, such as long-range air transport of atmospheric emissions, as the prime source of PCDD/Fs to the Baltic Sea region. The half-life of PCDD/Fs in Baltic Sea offshore sediments was estimated to be approximately 2 and 4-6 times longer than in semirural and urban European air, respectively. This study highlights the need for further international actions to reduce the levels of PCDD/Fs in Baltic Sea air specifically and in European air in general.

  • 217.
    Assefa, Anteneh Taye
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sundqvist, KL
    Cato, I
    Jonsson, P
    Sobek, A
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wiberg, Karin
    Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU) Uppsala.
    Trends of PCDD/FS in coastal and offshore Baltic Sea sediment cores covering the 20th century2012Conference paper (Refereed)
  • 218.
    Assefa, Anteneh Taye
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Sobek, Anna
    Stockholm Univ, Dept Appl Environm Sci ITM, SE-10691 Stockholm, Sweden.
    Sundqvist, Kristina
    AF AB, SE-90347 Umeå, Sweden.
    Geladi, Paul
    Swedish Univ Agr Sci SLU, SE-90183 Umeå, Sweden.
    Wiberg, Karin
    Swedish Univ Agr Sci SLU, Dept Aquat Sci & Assessment, SE-75007 Uppsala, Sweden.
    Assessment of PCDD/F Source Contributions in Baltic Sea Sediment Core Records2014In: Environmental Science and Technology, ISSN 1086-931X, E-ISSN 1520-6912, Vol. 48, no 16, p. 9531-9539Article in journal (Refereed)
    Abstract [en]

    Spatial and temporal trends of sources of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea were evaluated by positive matrix factorization (PMF) and principal component analysis (PCA). Sediment cores were sampled at eight coastal, one coastal reference, and six offshore sites covering the northern to the southern Baltic Sea. The cores, which covered the period 1919-2010, were sliced into 2-3 cm disks among which 8-11 disks per core (in total 141 disks) were analyzed for all tetra- through octa-CDD/Fs. Identification and apportionment of PCDD/F sources was carried out using PMF. Five stable model PCDD/F congener patterns were identified, which could be associated with six historically important source types: (i) atmospheric background deposition (ABD), (ii) use and production of penta-chlorophenol (PCP), (iii) use and production of tetra-chlorophenol (TeCP), (iv) high temperature processes (Thermal), (v) hexa-CDD-related sources (HxCDD), and (vi) chlorine-related sources (Chl), all of which were still represented in the surface layers. Overall, the last four decades of the period 1920-2010 have had a substantial influence on the Baltic Sea PCDD/F pollution, with 88 ± 7% of the total amount accumulated during this time. The 1990s was the peak decade for all source types except TeCP, which peaked in the 1980s in the northern Baltic Sea and has still not peaked in the southern part. The combined impact of atmospheric-related emissions (ABD and Thermal) was dominant in the open sea system throughout the study period (1919-2010) and showed a decreasing south to north trend (always >80% in the south and >50% in the north). Accordingly, to further reduce levels of PCDD/Fs in the open Baltic Sea ecosystem, future actions should focus on reducing atmospheric emissions.

  • 219.
    Assefa, Anteneh
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Department of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Bignert, Anders
    Josefsson, Sarah
    Wiberg, Karin
    Sources of polychlorinated dibenzo-p-dioxins and dibenzofurans to Baltic Sea herring2019In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 218, p. 493-500Article in journal (Refereed)
    Abstract [en]

    Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in herring (Clupea harengus) remain high in several parts of the Baltic Sea, despite declines in PCDD/F emissions since the 1980s. The reasons behind this are not well understood. This study applied a statistical modeling approach where sources of PCDD/Fs that contaminate Baltic biota were quantitatively assessed by analyzing existing datasets. PCDD/F patterns were extracted from a herring dataset using positive matrix factorization (PMF). The extracted biota patterns were transformed into sediment patterns using fish-to-sediment transformation factors, and the resulting patterns were compared with known source PCDD/F patterns. The model distinguished three model patterns, which explained 85% of the data. These patterns were matched to tetra-chlorophenol (TCP), penta-chlorophenol/atmospheric background (PCP/AB), and thermal source patterns, respectively. The thermal source was the largest contributor to toxic equivalents (TEQ) in herring, but the level decreased from 42 ± 9.0 pg TEQ g−1 lipid weight (lw) before year 2000 (pre-2000) to 15 ± 2.4 pg TEQ g−1 lw post-2000, i.e., a decline of around one-third in the original TEQ concentration. The contribution of TCP more than doubled, from 2.1 ± 0.62 pg TEQ g−1 lw to 5.6 ± 1.1 pg TEQ g−1 lw, and the relative contribution of PCP/AB also increased. These increasing trends suggest that, as primary air emissions of PCDD/Fs are managed and levels decline, the impact of TCP and PCP/AB sources on Baltic Sea biota will become more important over time and that PCDD/F-contaminated sites in coastal areas and marine environments require more attention.

  • 220.
    Assefa, Anteneh
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Bignert, Anders
    Wiberg, Karin
    Source-apportionment shows why dioxin levels have not declined in Baltic fishManuscript (preprint) (Other academic)
    Abstract [en]

    Levels of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs, “dioxins”) in fatty fish of the Baltic Sea have remained high despite declines in environmental levels since the 1980s. This has raised human health concerns and restricted marketing of Baltic herring and salmon within the European Union. Thus, there is an urgent need to identify and control current PCDD/F emission sources. Analysis presented here explains why PCDD/Fs levels in fish have stopped declining or even increased in recent decades. We show that contributions of “thermal” sources (e.g., waste incineration) of PCDD/Fs to Baltic fish have declined since the 1990s, but not contributions of sources associated with the manufacture and use of chlorophenols (particularly tetrachlorophenol and pentachlorophenol, TCP and PCP, respectively). Moreover, the discrepancy between declines in levels of dioxins in abiotic compartments (e.g. sediments and air), and stable or increasing levels in biota can be explained by the persistently high bioavailability of PCDD/Fs associated with TCP and PCP type sources.

  • 221.
    Assefa, Anteneh
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry. Dept. of Aquatic Sciences and Assessment, Swedish University of Agricultural Sciences (SLU), Uppsala, Sweden .
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Klanova, Jana
    Wiberg, Karin
    Tracing the sources of PCDD/Fs in Baltic Sea air by using metals as source markers2018In: Environmental Science: Processes & Impacts, ISSN 2050-7887, E-ISSN 2050-7895, Vol. 20, no 3, p. 544-552Article in journal (Refereed)
    Abstract [en]

    The atmosphere is the major contributor of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the Baltic Sea environment. In this study, we investigated the potential of using metals along with PCDD/Fs as markers of important emission sources of PCDD/Fs in air. The air concentrations of PCDD/F congeners (n = 17), other persistent organic pollutants (n = 8) and metals (n = 16) were determined in summer and winter air using high volume samplers at a rural field station (Aspvreten, Sweden) located close to the Baltic Sea coast. During winter, PCDD/F levels were on average 20 times higher than in summer (5.1 +/- 5.8 fg toxicity equivalents (TEQ) m-3 and 0.26 +/- 0.18 fg TEQ m-3, respectively) mostly due to a higher fraction of PCDFs. The increased levels of PCDD/Fs were pronounced mainly in air masses that had travelled from southern (S) and eastern (E) compass sectors. A principal component analysis (PCA) of metal levels in Scots pine (Pinus sylvestris) needles sampled to reflect various air emission source types helped to identify potential marker metals for selected known atmospheric emission sources of PCDD/Fs and to rank among the candidate source types. Brown coal burning, domestic burning and heavy oil burning appeared to be the source types that contribute most of the PCDD/Fs in Baltic Sea air. The current study demonstrates a successful approach for source tracing of PCDD/Fs in air, where integrated indices from seasonal and spatial patterns of PCDD/Fs as well as metal source markers were used to trace and rank sources.

  • 222. Athely, Karin
    et al.
    Ulmgren, Per
    Öhman, Lars-Olof
    Umeå University, Faculty of Science and Technology, Chemistry.
    Acid-base properties of oxygen-delignified kraft pulps2001In: Nordic Pulp & Paper Research Journal, Vol. 16, no 3, p. 195-203Article in journal (Refereed)
    Abstract [en]

    The acid-base properties of oxygen-delignified kraft pulps have been investigated in 0.02 and 0.10 mol/L (Na)Cl-media at 25 degreesC. The measurements have been performed with high precision potentiometric titrations in the pH-range of 3 to 5.5. The acid-base properties were ascribed to fibre-bound carboxylate groups. The acid-base reaction is affected by the charge arising in the fibre when the acid groups are deprotonated, and can be described by an intrinsic constant, beta (s)(1,1(intr.)) valid for an uncharged surface, and a capacitance of the electrical double layer, representing the influence of the surface charge. Two investigated softwood pulps were found to have similar acid-base properties having log beta (s)(1,1(intr.))-values of 3.20 and 3.25 respectively in 0.02 mol/L (Na)Cl, while the investigated hardwood pulp had a log beta (s)(1,1(intr.))-value of 3.45. When the strength of the ionic medium increased, the acid strength of the fibre-bound carboxylic acid groups increased. The influence of the charged groups on the acid-base properties is affected by the ionic strength and the distance between the acid groups on the fibre. The charged groups had the smallest influence on the acid-base properties in the hardwood, even though the amount of acid groups per unit weight was approximately twice that in the softwood.

  • 223.
    Augulyte, Lijana
    Umeå University, Faculty of Science and Technology, Chemistry.
    Use and Development of Diffusive Samplers to Analyse the Fate of Polycyclic Aromatic Compounds, Polychlorinated Biphenyls and Pharmaceuticals in Wastewater Treatment Processes2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The efficiency of wastewater treatment systems is commonly measured by the reductions of parameters such as biological oxygen demand (BOD), chemical oxygen demand (COD) and total suspended solids (TSS) and/or reductions in levels of selected macro compounds (e.g. long-chained hydrocarbons and inorganic compounds). Less attention has generally been paid to micropollutants with high potential toxic effects, such as polycyclic aromatic compounds (PACs), including unsubstituted and alkylated polycyclic aromatic hydrocarbons (PAHs) and dibenzothiophenes, polychlorinated biphenyls (PCBs), human pharmaceuticals and by-products formed during the treatment process. These organic micropollutants occur in wastewaters at trace and ultra-trace levels, therefore their detection requires advanced, costly analyses and large sample volumes. Furthermore, concentrations of micropollutants can fluctuate widely both diurnally and between days. Thus, in order to understand the fate of micropollutants in wastewaters there is a need to develop sampling techniques that allow representative samples to be readily collected.

    In the work underlying this thesis two types of diffusive passive samplers, semipermeable membrane devices (SPMDs) and polar organic chemical integrative samplers (POCISs), were used to monitor non-polar and polar organic micropollutants in wastewaters subjected to various treatment processes. The pollutants sequestered in these samplers represent micropollutants in the dissolved phase that are available for aquatic organisms. Further, since they collect pollutants in an integrative manner, i.e. they sample continuously during the selected exposure time (usually approx. one to ca. three weeks), the results provide time-weighted average (TWA) concentrations. In addition, the effects of various environmental factors on the uptake of analyzed micropollutants in POCISs and SPMDs were investigated using laboratory calibration and in situ calibration with performance reference compounds (PRCs).

    The results confirm that SPMDs are good sampling tools for investigating the efficacy of wastewater treatment processes for removing non-polar PACs and PCBs, and the effects of varying the process settings. In addition, analyses of process streams in municipal sewage treatment plants demonstrated that conventional sewage treatment processes are not optimized for removing dissolved four-ringed PAHs, some of the five-ringed PAHs, and tri- to hexa-chlorinated biphenyls. The removal of bioavailable PACs was enhanced by adding sorbents with high sorption capacities to the sludge used in the activated sludge treatment step, and a biologically activated carbon system was designed that robustly removed bioavailable PACs, with removal efficiencies of 96.9-99.7 percent across the tested ranges of five varied process parameters.

    In situ SPMD calibration data acquired show that uptake of PACs, described by SPMD sampling rates (Rs), were four to eight times higher than published laboratory calibrated Rs values, mainly due to strong (bio)fouling and turbulence effects. In addition, the laboratory calibration study demonstrated that temperature affects the POCIS uptake of pharmaceuticals. The uptake of four pharmaceuticals was higher, by 10-56 percent, at 18 °C compared to 5 °C. For two of the pharmaceuticals our data indicate that the uptake was lower by 18-25 percent at 18 °C. Our results also indicate that uptake of the studied pharmaceuticals was in the linear phase throughout the 35 day exposure period at both temperatures. Finally, calibration studies enabled aqueous concentrations of micropollutants to be more accurately estimated from amounts collected in the passive samplers.

  • 224.
    Augulyte, Lijana
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Bergqvist, Per-Anders
    Umeå University, Faculty of Science and Technology, Chemistry.
    Estimation of Water Sampling Rates and Concentrations of PAHs in a Municipal Sewage Treatment Plant Using SPMDs with Performance Reference Compounds2007In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851, Vol. 41, no 14, p. 5044-5049Article in journal (Refereed)
    Abstract [en]

    Semipermeable membrane devices (SPMDs) were exposed at ten sampling points, each representing a different stage in the treatment process, in a municipal sewage treatment plant. Differences in SPMD uptake kinetics of polycyclic aromatic hydrocarbons (PAHs) due to variations in conditions at the sampling sites were evaluated by using five performance reference compounds (PRCs) with log Kow values of 4.20 to 6.34. PRC release rate constants (ke,PRC values) were calculated for PRCs for which 50-98% of the initial amounts were lost during the sampling period. The ke,PRC values were high, ranging from 0.08 to 0.11 day-1 for the studied PRCs, at sampling site W1 (raw sewage), the only sampling site where significant amounts of the PRCs with log Kow values >5 were released from the SPMDs. At the other sampling sites, only PRCs with log Kow values between 4.20 and 4.50 were released in significant amounts. The release rates at these sites were lowest (0.04 day-1) at sampling site W9 (the secondary clarifier) and highest (0.18 day-1) at W8 (the active sludge aeration basin). Differences between sampling rates (Rs) obtained using published laboratory-calibrated data and PRC-corrected Rs values were visualized by principal component analysis (PCA). The water concentrations of 24 studied PAHs fell substantially during the course of the sewage treatment process. However, low molecular weight PAHs were more effectively removed than high molecular weight PAHs. Significant deviations between actual and estimated water concentrations may arise unless PRC-corrected Rs values are applied.

  • 225.
    Augulyte, Lijana
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Kliaugaite, D
    Racys, V
    Jankunaite, D
    Zaliauskiene, A
    Andersson, Patrik
    Umeå University, Faculty of Science and Technology, Chemistry.
    Bergqvist, Per-Anders
    Umeå University, Faculty of Science and Technology, Chemistry.
    Chemical and Ecotoxicological Assessment of Selected Biologically Activated Sorbents for Treating Wastewater Polluted with Petroleum Products with Special Emphasis on Polycyclic Aromatic Hydrocarbons2008In: Water, Air, & Soil Pollution, ISSN 0049-6979 (Print) 1573-2932 (Online), Vol. 195, no 1-4, p. 243-56Article in journal (Refereed)
    Abstract [en]

    A chemical and ecotoxicological assessment of treatment of wastewater that had been polluted with petroleum products using only Activated Sludge (AS) and four biologically activated sorbents (BASs), consisting of activated sludge plus: coal-based activated carbon (-C1), coconut shell-based activated carbon (-C2), zeolite (-Z), and anthracite (-A) were conducted. The efficiency and robustness of the four wastewater treatment systems were evaluated by calculating the reduced total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) contents and the acute ecotoxicity of the effluents. The chemical analysis showed that the combined treatment systems were very effective for reducing the total petroleum hydrocarbon and readily bioavailable PAH contents. The most efficient systems were the BAS-C1 and -C2, which removed 60–88% and 99.5–99.6% of TPH and PAH, respectively. The activated sludge-only treatment was the least effective for purifying the wastewater. Chemical oxygen demand was reduced by >90% by all carbon-based BASs (BAS-C1, BAS-C2 and BAS-A). Shifts in the relative composition of the individual PAHs were identified in samples taken before and after treatment. Algal and bacterial bioassays showed that the toxicities of effluents following treatment by all four systems (except AS for algae) were reduced by more than 80% and 90%, respectively. However, crustacean tests indicated that the carbon-based BASs reduced the toxicity [V tox(50)] only by 19–67%. Our results indicated that the combination of sorption and biodegradation processes have great potential in the treatment of petroleum products polluted wastewater and is less sensitive for inhibitors of the biological process than treatments in which activated sludge alone is used. The assessment of chemical and ecotoxicological endpoints provided valuable information, but contrasting results for one of the assays indicates that further analysis on the capacity of the different treatment systems is warranted.

  • 226.
    Augulyte, Lijana
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Kliaugaite, Daina
    Racys, Viktoras
    Jankunaite, Dalia
    Zaliauskiene, Audrone
    Bergqvist, Per-Anders
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Multivariate analysis of a biologically activated carbon (BAC) system and its efficiency for removing PAHs and aliphatic hydrocarbons from wastewater polluted with petroleum products2009In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 170, no 1, p. 103-110Article in journal (Refereed)
    Abstract [en]

    The efficiency of a biologically activated carbon system for treating wastewater polluted with petroleum products was examined and the effects of process parameters on its efficacy were evaluated. In each experiment 17 alkylated and 19 non-alkylated polycyclic aromatic hydrocarbons (PAHs) and total petroleum hydrocarbons (TPHs, C10-C40) were extracted using semipermeable membrane devices from wastewater before and after treatment. The acquired data during experiments were analyzed using principal component analysis (PCA). The treatment system robustly removed dissolved PAHs across the studied ranges of the process parameters, providing overall removal efficiencies of 96.9-99.7% for the sum of 36 PAHs. However, the major contributor to their removal was sorption rather than biodegradation, and despite the general efficiency of the process there was up to a 9-fold range in the sums of quantified PAHs in the effluents between experiments. Combinations of long process contact time (24 h) with high temperature (24 degrees C) and moderate oxygen concentration (6-7mg O2 L-1) resulted in good removal of bioavailable PAHs. The removal of TPHs was more dependent on biological activities during the wastewater treatment, and consequently more dependent on the process parameters. In addition, small but significant proportions of PAHs were volatilized and released during the wastewater treatment.

  • 227.
    Augulyte, Lijana
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lindberg, Richard H
    Andersson, Patrik L
    Umeå University, Faculty of Science and Technology, Chemistry.
    Söderström, Hanna
    Laboratory evaluation of the temperature effect on the uptake of selected pharmaceuticals by the polar organic chemical integrative sampler (POCIS)Manuscript (Other academic)
  • 228. Aulin, Christian
    et al.
    Shchukarev, Andrey
    Umeå University, Faculty of Science and Technology, Chemistry.
    Lindqvist, Josefina
    Malmström, Eva
    Wågberg, Lars
    Lindström, Tom
    Wetting kinetics of oil mixtures on fluorinated model cellulose surfaces2008In: Journal of Colloid and Interface Science, Vol. 317, no 2, p. 556-67Article in journal (Refereed)
    Abstract [en]

    The wetting of two different model cellulose surfaces has been studied; a regenerated cellulose (RG) surface prepared by spin-coating, and a novel multilayer film of poly(ethyleneimine) and a carboxymethylated microfibrillated cellulose (MFC). The cellulose films were characterized in detail using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM indicates smooth and continuous films on a nanometer scale and the RMS roughness of the RG cellulose and MFC surfaces was determined to be 3 and 6 nm, respectively. The cellulose films were modified by coating with various amounts of an anionic fluorosurfactant, perfluorooctadecanoic acid, or covalently modified with pentadecafluorooctanyl chloride. The fluorinated cellulose films were used to follow the spreading mechanisms of three different oil mixtures. The viscosity and surface tension of the oils were found to be essential parameters governing the spreading kinetics on these surfaces. XPS and dispersive surface energy measurements were made on the cellulose films coated with perfluorooctadecanoic acid. A strong correlation was found between the surface concentration of fluorine, the dispersive surface energy and the contact angle of castor oil on the surface. A dispersive surface energy less than 18 mN/m was required in order for the cellulose surface to be non-wetting (θe>90°) by castor oil.

    Graphical abstract

    AFM tapping mode image of a bilayer of PEI/MFC on silica in the height mode. The scanned surface area was 1 μm2 (left) and dispersive surface energy of fluorinated regenerated cellulose surfaces vs atomic fluorine concentration (right).

  • 229. Aune, Marie
    et al.
    Bjerselius, Rickard
    Atuma, Samuel
    Darnerud, Per Ola
    Andersson, Arne
    Arrhenius, Fredrik
    Bergek, Sture
    Umeå University, Faculty of Science and Technology, Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Chemistry.
    Glynn, Anders
    Large Differences in Dioxin and PCB Levels in Herring and Salmon Depending on Tissue Analysed2003In: Organohalogen Compounds, Vol. 64, p. 378-81Article in journal (Refereed)
  • 230.
    Aurell, Johanna
    Umeå University, Faculty of Science and Technology, Chemistry.
    Effects of Varying Combustion Conditions on PCDD/F Formation2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are by-products emitted from combustion sources such as municipal solid waste (MSW) incineration plants. These organic compounds are recognized as toxic, bioaccumulative and persistent in the environment. PCDD/Fs are removed from flue gases before released from MSW incineration. However, the PCDD/Fs are not destroyed but retained in the residues, thus in the environment. Understanding the pathways that lead to their formation is important in order to develop ways to suppress their formation and prevent their release into the environment. Suppressing the formation can also allow less expensive air pollution control system to be used, and/or the costs of thermally treating the residues to be reduced. The main objective of the studies underlying this thesis was to elucidate process, combustion and fuel parameters that substantially affect the emission levels and formation of PCDD/Fs in flue gases from MSW incineration. The experiments were conducted under controllable, realistic combustion conditions using a laboratory-scale reactor combusting artificial MSW.

    The parameter found to most strongly reduce the PCDD/F emissions, was prolonging the flue gas residence time at a relatively high temperature (460°C). Increasing the sulfur dioxide (SO2) to hydrogen chloride (HCl) ratio to 1.6 in the flue gas was also found to reduce the PCDF levels, but not the PCDD levels. Fluctuations in the combustion process (carbon monoxide peaks), high chlorine levels in the waste (1.7%) and low temperatures in the secondary combustion zone (660°C) all tended to increase the emission levels. The PCDD/PCDF ratio in the flue gas was found to depend on the chlorine level in the waste, fluctuations in the combustion process and the SO2:HCl ratio in the flue gas. The formation pathways were found to be affected by the quench time profiles in the post-combustion zone, fluctuations in the combustion process and addition of sulfur. In addition, increased levels of chlorine in the waste increased the chlorination degrees of both PCDDs and PCDFs. A tendency for increased SO2 levels in the flue gas to increase levels of polychlorinated dibenzothiophenes (sulfur analogues of PCDFs) was also detected, however the increases were much less significant than the reduction in PCDF levels.

  • 231.
    Aurell, Johanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Fick, Jerker
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Marklund, Stellan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Effects of sulfur on PCDD/F formation under stable and transient combustion conditions during MSW incineration2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 76, no 6, p. 767-773Article in journal (Refereed)
    Abstract [en]

    SO2 levels in the flue gas from a laboratory-scale fluidized bed reactor combusting artificial municipal solid waste (MSW) were varied (resulting in four different SO2:HCl ratios 0, 0.2, 0.7 and 2.7 (by mass)) to study the effects of sulfur on the formation of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs) and polychlorinated dibenzothiophenes (PCDTs). Sampling was performed simultaneously at three fixed points in the post-combustion zone with temperatures of 400, 300 and 200 °C, under normal combustion conditions and both during and after transient combustion conditions. The findings indicate that sulfur has a greater inhibitory effect on PCDF formation than on PCDD formation and that the PCDD/PCDF ratio in the flue gas depends on both the SO2:HCl ratio in the flue gas and memory effects arising from transient combustion conditions. The results also indicate that the relative importance of different pathways shifts in the post-combustion zone; condensation products increasing with reductions in temperature and increases in residence time. However, these changes appear to depend on the SO2:HCl ratio in the flue gas and combustion conditions. Sulfur seems to inhibit the chlorination of PCDFs. A tendency for increased SO2 levels in the flue gas to increase levels of PCDTs was also detected, but the increases were much less significant than the reductions in PCDF levels.

  • 232.
    Aurell, Johanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Fick, Jerker
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Marklund, Stellan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Effects of transient combustion conditions on the formation of polychlorinated dibenzo-p-dioxins, dibenzofurans, and benzenes, and polycyclic aromatic hydrocarbons during municipal solid waste incineration2009In: Environmental Engineering Science, ISSN 1092-8758, E-ISSN 1557-9018, Vol. 26, no 3, p. 509-520Article in journal (Refereed)
    Abstract [en]

    This study investigated the effects of transient combustion conditions on formation of polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) along the postcombustion zone. Polychlorinated benzenes (PCBz) and polycyclic aromatic hydrocarbons (PAH) were also studied. The study was conducted in a laboratory fluidized-bed reactor fed with an artificial municipal solid waste (MSW) under controllable but realistic combustion conditions. PCDD/Fs, PCBz, and PAHs were monitored under normal, transient, and posttransient combustion conditions and simultaneously sampled at three different sampling points/temperatures (400°C, 300°C, and 200°C). Substantially higher PCDD/F, PCBz, and PAH concentrations were found during transient combustion than during normal combustion. Elevated concentrations were found to decrease with time. PCDD/F concentrations were similar at all points during normal and transient combustion conditions, but were found in higher concentrations at 200°C than 400°C under the posttransient combustion periods. Higher concentrations of the sum PAH and PCBz were also found at 200°C than 400°C in the posttransient combustion periods. Transient combustion conditions induced changes in both PCDD/F homologue profile and PCDD/F congener patterns compared to normal combustion. PCDD/PCDF ratios indicated an increase of the de novo synthesis during transient combustion conditions. Although, the PCDD/F congeners found to be most strongly affected by the transient combustion conditions indicated different reactions pathways active for formation of PCDF and PCDD, de novo synthesis and precursors, respectively. The most strongly affected PCDD/F congeners of transient combustion were identified and are presented.

  • 233.
    Aurell, Johanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Jansson, Stina
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Marklund, Stellan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Effects of quench time profiles on PCDD/F formation in the postcombustion zone during municipal solid waste incineration2009In: Environmental Engineering Science, ISSN 1092-8758, E-ISSN 1557-9018, Vol. 26, no 3, p. 541-550Article in journal (Refereed)
    Abstract [en]

    Effects of postcombustion zone temperatures and flue gas residence times on monochlorinated to octachlorinated dibenzo-p-dioxins and -furans (PCDD/F) in a laboratory-scale reactor combusting municipal solid waste were investigated. Four different quench time profiles were investigated, falling from 400°C to 200°C, 300°C to 100°C, 450°C to 200°C and 460°C to 260°C, with corresponding residence times of 1.4 to 4.4sec, 1.4 to 5.4sec, 1.3 to 4.3sec, and 1.3 to 4.0sec, respectively. Flue gas samples were collected simultaneously at three fixed sampling points, with an additional sampling of flue gas entering the postcombustion zone (640°C). The quench time profiles resulted in different total PCDD/F yields, as well as differences in homologue profiles and congener patterns. Thus, the formation pathways seem to be dependent on sufficient residence time within a specific temperature region. Formation of PCDD/F was shown to be rapid and mainly located to the 640°C to 400°C temperature region, with non-detectable levels at 640°C and concentrations at 400°C that did not increase or decrease significantly downstream. Furthermore, a prolonged residence time at and above 450°C/ 460°C showed low yields even downstream the postcombustion zone compared to the 400°C to 200°C and 300°C to 100°C profiles. The 460°C to 260°C profile resulted in increased abundance at the last two sampling points of PCDD congeners known to correlate with 2,4,6-trichlorophenols, suggesting that chlorophenol condensation reactions were promoted by this quench time profile.

  • 234.
    Aurell, Johanna
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Jansson, Stina
    Umeå University, Faculty of Science and Technology, Chemistry.
    Marklund, Stellan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Formation of Dioxins in a Modified Laboratory-Scale Fluidize-Bed Reactor During a Long-Term MSW Combustion Experiment2006In: Organohalogen Compounds, Vol. 68, p. 1205-8Article in journal (Refereed)
  • 235.
    Aurell, Johanna
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Marklund, Stellan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Effects of varying combustion conditions on PCDD/F emissions and formation during MSW incineration2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 75, no 5, p. 667-673Article in journal (Refereed)
    Abstract [en]

    Process, combustion and fuel parameters were varied to elucidate factors that substantially affect the formation and emissions of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) arising from municipal solid waste (MSW) incineration. The combustion conditions were varied by changing the: freeboard temperatures; quench time in the post-combustion zone; fuel load; chlorine and copper levels in the fuel; and the water, sulfur dioxide, carbon monoxide and oxygen levels in the combustion gases. The study was performed using a 5 kW laboratory-scale fluidized-bed reactor and PCDD/Fs were sampled at a point at 300 °C in the post-combustion zone. The results showed that increasing the SO2 level (from 0 to 130 ppm) substantially reduced the PCDD/F emissions, by up to 60%. In contrast, increasing the CO levels (due to transient combustion conditions), raising the Cl level (from 0.7% to 1.7%) and reducing the freeboard temperature (from 800 °C to 660 °C) all substantially increased the emission levels (more than 3-fold). Changes in PCDD/F profiles associated with increases in Cl, SO2 or CO levels and increasing the freeboard temperature (from 800 °C to 950 °C) indicate that the PCDFs were mainly formed by chlorination. In addition, increasing the Cl level increased the chlorination activity in the formation of PCDDs. Increasing the SO2 level appeared to be less effective in reducing the amount of PCDDs formed via the precursor pathway. While increased CO levels induced PCDD formation via the precursor pathway, although this was found to depend on the O2 level in the flue gas.

  • 236. Auzzas, Luciana
    et al.
    Larsson, Andreas
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Matera, Riccardo
    Baraldi, Annamaria
    Deschênes-Simard, Benoît
    Giannini, Giuseppe
    Cabri, Walter
    Battistuzzi, Gianfranco
    Gallo, Grazia
    Ciacci, Andrea
    Vesci, Loredana
    Pisano, Claudio
    Hanessian, Stephen
    Non-natural macrocyclic inhibitors of histone deacetylases: design, synthesis, and activity2010In: Journal of Medicinal Chemistry, ISSN 0022-2623, E-ISSN 1520-4804, Vol. 53, no 23, p. 8387-8399Article in journal (Refereed)
    Abstract [en]

    Nonpeptidic chiral macrocycles were designed on the basis of an analogue of suberoylanilide hydroxamic acid (2) (SAHA, vorinostat) and evaluated against 11 histone deacetylase (HDAC) isoforms. The identification of critical amino acid residues highly conserved in the cap region of HDACs guided the design of the suberoyl-based macrocycles, which were expected to bear a maximum common substructure required to target the whole HDAC panel. A nanomolar HDAC inhibitory profile was observed for several compounds, which was comparable, if not superior, to that of 2. A promising cytotoxic activity was found for selected macrocycles against lung and colon cancer cell lines. Further elaboration of selected candidates led to compounds with an improved selectivity against HDAC6 over the other isozymes. Pair-fitting analysis was used to compare one of the best candidates with the natural tetrapeptide apicidin, in an effort to define a general pharmacophore that might be useful in the design of surrogates of peptidic macrocycles as potent and isoform-selective inhibitors.

  • 237. Avdeef, Alex
    et al.
    Artursson, Per
    Neuhoff , Sibylle
    Lazorova, Lucia
    Gråsjö, Johan
    Tavelin, Staffan
    Umeå University, Faculty of Science and Technology, Chemistry.
    Caco-2 permeability of weakly basic drugs predicted with the Double-Sink PAMPA method:          2005In: European Journal of Pharmaceutical Sciences, Vol. 24, no 4, p. 333-49Article in journal (Refereed)
    Abstract [en]

    The aim of this study was to analyze pH-dependent permeability of cationic drugs in Caco-2 cell monolayers using the method and to correlate the results with those obtained in PAMPA (parallel artificial membrane permeability assay). The pH-dependent permeability of verapamil and propranolol was studied in Caco-2 cell monolayers. The data were subsequently processed using software developed for the PAMPA method. Literature values for an additional nine cationic drugs were also analyzed. Double-Sink PAMPA data were also obtained for the same cationic drugs, to compare with the Caco-2 data. The Algorithm Builder program was then used to develop a predictive model of Caco-2 permeability based on PAMPA permeability and calculated Abraham molecular descriptors. From the relationship between permeability and pH it was shown that in PAMPA only the uncharged form of the drugs permeated across the membrane barrier, while charged and ionized forms of the drugs were significantly permeable in Caco-2. The charged-form permeability, Pi, was therefore determined and subsequently subtracted from all permeability coefficients in Caco-2 prior to the comparison with PAMPA. The resulting intrinsic permeability coefficients (Po) obtained in Caco-2 were successfully related to those derived from the PAMPA model. In this study we have shown that permeability coefficients obtained in PAMPA can predict the passive transcellular permeability in Caco-2.

  • 238.
    Axe, Kristina
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    Time-dependent surface speciation of oxalate at the water-boehmite (γ-AlOOH) interface: implications for dissolution2001In: Geochimica et Cosmochimica Acta, Vol. 65, no 24, p. 4481-92Article in journal (Refereed)
    Abstract [en]

    The surface speciation of oxalate at the water-boehmite (γ-AlOOH) interface during adsorption and dissolution reactions was studied by means of attenuated total reflectance infrared spectroscopy. The structural interpretations of infrared (IR) data were based on comparison with results from theoretical frequency calculations. Two different surface complexes were identified: an inner-sphere complex with a bidentate five-membered chelate structure involving both carboxylate groups; and a hydrogen-bonded surface complex with no direct bonding to Al atoms. A scheme was developed by which the surface concentrations of these complexes could be determined from IR spectroscopy data. The concentration of the hydrogen bonded complex was shown to be strongly dependent on the experimental conditions, and the concentration of the inner-sphere complex was comparatively insensitive to the conditions within the studied experimental range. The dissolution data indicated that an excess of oxalate with respect to a critical surface concentration of oxalate was necessary to induce significant boehmite dissolution. Under dissolving conditions, the concentration of the inner-sphere complex was shown to be almost identical to this critical concentration and thus a stable entity.

  • 239. Axe, Kristina
    et al.
    Vejgården, Marie
    Persson, Per
    Umeå University, Faculty of Science and Technology, Chemistry.
    An ATR-FTIR spectroscopic study of the competitive adsorption between oxalate and malonate at the water-goethite interface.2006In: Journal of Colloid and Interface Science, ISSN 0021-9797, Vol. 294, no 1, p. 31-7Article in journal (Refereed)
    Abstract [en]

    The competitive adsorption between oxalate and malonate at the water-goethite interface was studied as a function of pH and total ligand concentrations by means of quantitative adsorption measurements and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy. The results obtained show that ATR-FTIR spectroscopy resolves the individual spectroscopic features of oxalate and malonate when adsorbed simultaneously at the water-goethite interface. The characteristic peaks of all four types of predominating surface complexes existing in the single ligand systems were identified, namely one inner sphere and one outer sphere surface complex for each ligand. The quantitative adsorption data showed that oxalate partially out-competes malonate at the water-goethite interface. Evaluation of the peak area variations as a function of pH indicated that the stronger oxalate adsorption can be ascribed to the more stable inner sphere surface complex of oxalate, which in turn is related to the oxalate five-member chelate ring structure yielding a more stable complex compared to the six-member ring of malonate.

  • 240. Azmi, Jahanara
    et al.
    Griffin, Julian L
    Antti, Henrik
    Umeå University, Faculty of Science and Technology, Chemistry.
    Shore, Richard F
    Johansson, Erik
    Nicholson, Jeremy K
    Holmes, Elaine
    Metabolic trajectory characterisation of xenobiotic-induced hepatotoxic lesions using statistical batch processing of NMR data: Nicholson Jeremy K., Holmes Elaine2002In: Analyst, Vol. 127, p. 271-6Article in journal (Refereed)
    Abstract [en]

    Multivariate statistical batch processing (BP) analysis of 1H NMR urine spectra was employed to establish time-dependent metabolic variations in animals treated with the model hepatotoxin, -naphthylisothiocyanate (ANIT). ANIT (100 mg kg-1) was administered orally to rats (n = 5) and urine samples were collected from dosed and matching control rats at time-points up to 168 h post-dose. Urine samples were measured via1H NMR spectroscopy and partial least squares (PLS) based batch processing analysis was used to interpret the spectral data, treating each rat as an individual batch comprising a series of timed urine samples. A model defining the mean urine profile over the 7 day study period was established, together with model confidence limits (±3 standard deviation), for the control group. Samples obtained from ANIT treated animals were evaluated using the control model. Time-dependent deviations from the control model were evident in all ANIT treated animals consisting of glycosuria, bile aciduria, an initial decrease in taurine levels followed by taurinuria and a reduction of tricarboxylic acid cycle intermediate excretion. BP provided an efficient means of visualising the biochemical response to ANIT in terms of both inter-animal variation and net variation in metabolite excretion profiles. BP also allowed multivariate statistical limits for normality to be established and provided a template for defining the sequence of time-dependent metabolic consequences of toxicity in NMR based metabonomic studies.

  • 241.
    Backman, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Alpha-actinin of the chlorarchiniophyte Bigelowiella natans2018In: PeerJ, ISSN 2167-8359, E-ISSN 2167-8359, Vol. 6, article id e4288Article in journal (Refereed)
    Abstract [en]

    The genome of the chlorarchiniophyte Bigelowiella natans codes for a protein annotated as an α-actinin-like protein. Analysis of the primary sequence indicate that this protein has the same domain structure as other α-actinins, a N-terminal actin-binding domain and a C-terminal calmodulin-like domain. These two domains are connected by a short rod domain, albeit long enough to form a single spectrin repeat. To analyse the functional properties of this protein, the full-length protein as well as the separate domains were cloned and isolated. Characerisation showed that the protein is capable of cross-linking actin filaments into dense bundles, probably due to dimer formation. Similar to human α-actinin, calcium-binding occurs to the most N-terminal EF-hand motif in the calmodulin-like C-terminal domain. The results indicate that this Bigelowiella protein is a proper α-actinin, with all common characteristics of a typical α-actinin.

  • 242.
    Backman, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Calcium affinity of human α-actinin12015In: PeerJ, Vol. 3, article id e944Article in journal (Refereed)
    Abstract [en]

    Due to alternative splicing, the human ACTN1 gene codes for three different transcripts of α-actinin; one isoform that is expressed only in the brain and two with a more general expression pattern. The sequence difference is located to the C-terminal domains and the EF-hand motifs. Therefore, any functional or structural distinction should involve this part of the protein. To investigate this further, the calcium affinities of these three isoforms of α-actinin 1 have been determined by isothermal calorimetry.

  • 243.
    Backman, Lars
    Umeå University, Faculty of Science and Technology, Chemistry.
    Calmodulin—Alias: Cyclic Nucleotide Phosphodiesterase Activator, Ca2+-Dependent Regulatory Protein2007In: Calcium Binding Proteins, ISSN Print ISSN: 1554-8643; Online ISSN: 1554-8651, Vol. 2, no 1, p. 1-3Article in journal (Other academic)
    Abstract [en]

    Calmodulin is an important intracellular receptor for calcium signals. Calcium-activated calmodulin interacts with a large number of targets, thereby transducing the signal to many cellular processes. Calmodulin is also the archetype for proteins binding calcium by the EF-hand motif.

  • 244.
    Backman, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Counter-current distribution of interacting molecules: simulation of distribution behaviour and application to protein-protein interactions1981Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Associations of biological macromolecules with other macromolecules, with larger assemblies of macromolecules and with themselves are widely encountered phenomena. In principle, these interactions can be studied with any method able to differentiate between free molecules and complexes formed. The most extensively used techniques are sedimentation equilibrium and velocity, elastic light scattering and molecular sieve chromatography. This thesis describes an alternative technique; counter-current distribution in aqueous two-phase systems.

    The counter-current distribution behaviour of a solute depends on its size and surface properties including charge and hydrophobicity. Since the surface properties of a complex formed most probably differ from those of the solutes participating in the association, complex formation should lead to changes in the average distribution behaviour of each solute. Consequently, the presence of one solute should affect the counter-current distribution of another solute if they interact with each other.

    In order to establish the boundary conditions and the potential as well as limitations of the counter-current distribution technique, the distribution behaviour of homogeneous and heterogeneous association equilibria have been simulated.

    The model developed for describing the distribution behaviour of heterogeneous associations has been tested using the well characterized interaction between bovine serum albumin and L-tryptophan. It was demonstrated that the theoretical model could predict the experimental distribution behaviour of these two molecules.

    However, the primary aim of the counter-current distribution experiments has been to gain insight into protein-protein interactions. The metabolically linked enzymes, malate dehydrogenase and aspartate aminotransferase, have been studied in order to determine if there is also a physical link between these two enzymes. The results showed that the cytosolic enzymes as well as the mitochondrial forms associate while the cytoplasmic enzymes did not display any association with the mitochondrial forms. Thus, an organelle specific interaction between malate dehydrogenase and aspartate aminotransferase was demonstrated.

    Hemoglobin and carbonic anhydrase are functionally linked through the Bohr effect. Thus, the binding of oxygen by hemoglobin in the lung capillaries is associated with the binding of protons which are formed by the catalytic action of carbonic anhydrase. From the counter- current distribution experiments it was possible to conclude that humain carbonic anhydrase II, the high activity form, associates with human hemoglobin whereas carbonic anhydrase I, the low activity form, did not show any affinity for hemoglobin.

  • 245.
    Backman, Lars
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Protein Chemistry2020Book (Refereed)
  • 246.
    Backman, Lars
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Persson, Karina
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The no-nonsens SDS-PAGE2018In: Schizosaccharomyces pombe: methods and protocols / [ed] Teresa L. Singleton, Humana Press, 2018, p. 89-94Chapter in book (Other academic)
    Abstract [en]

    The discontinuous polyacrylamide gel electrophoresis system devised by Laemmli (Nature 227:680–685, 1970) has not only been used in numerous laboratories but has also been modified in several ways since its birth. In our laboratories, we use a modified Laemmli SDS-PAGE system for following protein purification as well as for analysis of certain protein-protein interactions, mainly involving filametous actin.

  • 247.
    Badea, Silviu
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundstedt, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Liljelind, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    The influence of soil composition on the leachability of selected hydrophobic organic compounds (HOCs) from soils using a batch leaching test2013In: Journal of Hazardous Materials, ISSN 0304-3894, E-ISSN 1873-3336, Vol. 254, p. 26-35Article in journal (Refereed)
    Abstract [en]

    The influence of soil composition (peat and clay content) on the leachability was investigated in batch leaching experiments for chemically diverse hydrophobic organic compounds (HOCs: PCP, PAHs, HCB, HCHs, PCBs, and TCDD/Fs). An experimental design was applied to generate 8 diverse soil matrices, and the results were evaluated by orthogonal projections to latent structures (OPLS), as well as compound specific response surface models. Overall, the distribution coefficients (log Kd) of model HOCs were in the range of approx. 2.0–5.7. The Kd-values of HCHs, phenanthrene and PCP were positively correlated with the peat content. Kd-values of benzo(a)anthracene, HCB, and PCB 47 were positively correlated with both peat and clay content. The Kd-values of 1,3,6,8-TCDD and 1,3,6,8-TCDF were positively correlated with peat content but negatively correlated with clay content, while for PCB 153 and PCB 155 the correlations were reversed. The correlation between the Kd-values and the compounds’ Kow-values was linearly for compounds with log Kow <6. For HOCs with log Kow > 6, the Kd-values were leveling off, possibly due to small particles in the leachates. Our study demonstrated how complex interaction between both the organic matter and clay components influences the leachability of HOCs in a compound-specific manner.

  • 248.
    Badea, Silviu-Laurentiu
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Association of hydrophobic organic compounds to organic material in the soil system2013Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Contaminated soils and sediments have been identified as significant secondary sources of organic contaminants.  Leaching tests may be useful tools to estimate the mobility of contaminants via the water phase and thereby the risk for groundwater and surface water contamination. The influence of soil composition (peat and clay content) on the leachability was investigated in batch leaching experiments for chemically diverse hydrophobic organic compounds (HOCs: PCP, PAHs, HCB, HCHs, PCBs, and TCDD/Fs). The above mentioned compounds were analyzed by both GC-LRMS (gas chromatography coupled with low resolution mass spectrometry (GC-HRMS) and GC-HRMS (gas chromatography coupled with high resolution mass spectrometry). Also the the leachability of eleven selected PCBs from naturally aged soil (Västervik, Sweden) was investigated in relation to the composition and concentration of dissolved organic matter at different pH (2 to 9), using a pH static test with initial acid/base addition. The the composition and of dissolved organic matter (DOM) at different pH values was explored by FTIR spectroscopy. The results were evaluated by orthogonal projections to latent structures (OPLS).

    Generally, for all model compounds studies, the Kd-values showed a variability of 2-3 orders of magnitude depending on the matrix composition. The Kd-values of moderately hydrophobic compounds, (e.g. HCHs, PCP and Phe), were correlated mainly with the organic matter content of soil. For more hydrophobic compounds (e.g.BaA, HCB and PCB 47), the leachability decreased as the proportions of  OM and clay contents increased. The Kd-values of 1,3,6,8-TCDD and 1,3,6,8-TCDF were  positively correlated with peat content but negatively correlated with clay content, while for PCB 153 and PCB 155 the correlations were reversed. The log Kd-values of all target PCBs decreased with increased pH values and the log Kd-values were highly correlated with the concentration of total organic carbon (TOC) in the leachates. The FTIR analysis of DOM showed that the least chlorinated and hydrophobic PCB congeners (i.e. PCB 28) might be associated with the hydrophilic fraction (i.e. carboxylic groups) of DOM. Our study demonstrated how complex interaction between the organic matter, clay components, pH and DOC influences the leachability of HOCs in a compound-specific manner.

  • 249.
    Badea, Silviu-Laurentiu
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Danet, Andrei-Florin
    Enantioselective stable isotope analysis (ESIA) - A new concept to evaluate the environmental fate of chiral organic contaminants2015In: Science of the Total Environment, ISSN 0048-9697, E-ISSN 1879-1026, Vol. 514, p. 459-466Article in journal (Refereed)
    Abstract [en]

    Since 2011, the enantiospecific stable carbon isotope analysis (ESIA) has emerged as an innovative technique to assess the environmental fate of chiral emerging compounds by combining in one experimental technique both compound specific isotope analysis (CSIA) and enantioselective analysis. To date, the ESIA was applied for four classes of compounds: alpha-hexachlorocyclohexane (alpha-HCH), polar herbicides (phenoxy acids), synthetic polycyclic musk galaxolide (HHCB), and phenoxyalkanoic methyl herbicides. From an analytical point of view there are factors that are hindering the application of ESIA methods for the field samples: (i.e. amounts of target analyte, matrix effects, GC resolution) and overcoming these factors is challenging. While ESIA was shown as a mature technique for the first three abovementioned class of compounds, no isotope analysis of individual enantiomers could be performed for phenoxyalkanoic methyl herbicides. With respect to field studies, one study showed that ESIA might be a promising tool to distinguish between biotic and abiotic transformation pathways of chiral organic contaminants and even to differentiate between their aerobic and anaerobic biotransformation pathways. The development of ESIA methods for new chiral emerging contaminants in combination with development of multi-element isotope analysis will contribute to a better characterization of transformation pathways of chiral organic contaminants. (C) 2015 Elsevier B.V. All rights reserved.

  • 250.
    Badea, Silviu-Laurentiu
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Lundstedt, Staffan
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Liljelind, Per
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Tysklind, Mats
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Assessment of the release of organic contaminants from soil using a batch leaching test2010Conference paper (Refereed)
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