Change search
Refine search result
1234 101 - 150 of 178
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 101.
    Malmvärn, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Brominated natural products at different trophic levels in the Baltic Sea: Identification of polybrominated dioxins, hydroxylated and methoxylated diphenyl ethers2007Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Over time, the Baltic Sea has been contaminated by increasing discharges of pollutants from human activities. Persistent organic pollutants (POPs) have caused toxic effects in wildlife and excess of nutrients have led to eutrophication. Furthermore, there are indications that certain polyhalogenated compounds similar in structure to man-made POPs are produced by the biota present in this sea. In the late 1990’s both methoxylated polybrominated diphenyl ethers (MeO-PBDEs) and hydroxylated-PBDEs (OH-PBDEs) were identified in fish and seals living in this environment. OH-PBDEs can originate from metabolism of PBDEs, but both OH- and MeO-PBDEs are also known to be natural products in marine environments. Another group of POPs, the polybrominated dibenzo-p-dioxins (PBDDs), are not produced commercially, but are known to be by-products of chemical industry and of the combustion of, e.g., brominated flame retardants (BFRs). In contrast to the OH- and MeO-PBDEs, PBDDs have not previously been shown to be natural products, although certain related compounds have been indicated to have a natural origin.

    This thesis describes the identification of PBDDs, OH-PBDEs and MeO-PBDEs in algae, blue mussels and fish living in the Baltic Sea. Several of these compounds were also detected in cyanobacteria. Moreover, PBDDs were present in fish, mussels, shrimp and crabs from different regions of the Baltic Sea and from the west coast of Sweden, but not in organisms from freshwater environments. The levels of these compounds in Baltic fish generally exceeded those of their chlorinated analogues. The origin of the PBDDs identified is somewhat unclear, but the high levels present in blue mussels and the pattern of congeners observed indicate natural production. The presence of PBDDs, OH-PBDEs and MeO-PBDEs in fish and shellfish constitutes a potential risk to both humans and wildlife and requires further investigation.

  • 102.
    Malmvärn, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Kautsky, Lena
    Athanasiadou, Maria
    Bergman, Åke
    Asplund, Lillemor
    Hydroxylated and Methoxylated Brominated Diphenyl Ethers in the Red Algae Ceramium tenuicorne and Blue Mussels from the Baltic Sea2005In: Environmental Science & Technology, ISSN 0013-936X, Vol. 39, no 9, p. 2990-2997Article in journal (Refereed)
  • 103.
    Malmvärn, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Zebuhr, Yngve
    Jensen, Sören
    Kautsky, Lena
    Greyerz, Erik
    Nakano, Takeshi
    Asplund, Lillemor
    Identification of Polybrominated Dibenzo-p-dioxins in Blue Mussels (Mytilus edulis) from the Baltic Sea2005In: Environmental Science & Technology, ISSN 0013-936X, Vol. 39, no 21, p. 8235-8242Article in journal (Refereed)
  • 104.
    Malmvärn, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Zebühr, Yngve
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Kautsky, Lena
    Stockholm University, Faculty of Science, Department of Botany.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Asplund, Lillemor
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Hydroxylated and methoxylated polybrominated diphenyl ethers and polybrominated dibenzo-p-dioxins in red alga and cyanobacteria living in the Baltic Sea2008In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 72, no 6, p. 910-916Article in journal (Refereed)
    Abstract [en]

    Hydroxylated polybrominated diphenyl ethers (OH-PBDEs) and methoxylated polybrominated diphenyl ethers (MeO-PBDEs) are present in the ecosystem of the Baltic Sea. OH-PBDEs are known to be both natural products from marine environments and metabolites of the anthropogenic polybrominated diphenyl ethers (PBDEs), whereas, MeO-PBDEs appear to be solely natural in origin. Polybrominated dibenzo-p-dioxins (PBDDs) are by-products formed in connection with the combustion of brominated flame retardants (BFRs), but are also indicated as natural products in a red alga (Ceramium tenuicorne) and blue mussels living in the Baltic Sea. The aims of the present investigation were to quantify the OH-PBDEs and MeO-PBDEs present in C. tenuicorne; to verify the identities of PBDDs detected previously in this species of red alga and to investigate whether cyanobacteria living in this same region of the Baltic Sea contain OH-PBDEs, MeO-PBDEs and/or PBDDs. The red alga was confirmed to contain tribromodibenzo-p-dioxins (triBDDs), by accurate mass determination and additional PBDD congeners were also detected in this sample. This is the first time that PBDDs have been identified in a red alga. The SigmaOH-PBDEs and SigmaMeO-PBDEs concentrations, present in C. tenuicorne were 150 and 4.6ngg(-1) dry weight, respectively. In the cyanobacteria 6 OH-PBDEs, 6 MeO-PBDEs and 4 PBDDs were detected by mass spectrometry (electron capture negative ionization (ECNI)). The PBDDs and OH-PBDEs and MeO-PBDEs detected in the red alga and cyanobacteria are most likely of natural origin.

  • 105. Mamun, M. I. R.
    et al.
    Zamir, Rausan
    Nilufar, Nahar
    Mosihuzzaman, M
    Linderholm, Linda
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Traditional organochlorine pollutants in blood from humans living in the Bangladesh capital area2007In: Organohalogen Compounds: Human exposure I (Level and trends), 2007, p. 2026-2030Conference paper (Refereed)
  • 106. Marsh, Göran
    et al.
    Hu, Jiwei
    Jakobsson, Eva
    Rahm, Sara
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Synthesis and characterization of 32 polybrominated diphenyl ethers1999In: Environmental Science and Technology, ISSN 0013-936X, Vol. 33, no 17, p. 3033-3037Article in journal (Refereed)
  • 107. Matsuoka, Atsuko
    et al.
    Onfelt, Agneta
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Matsuda, Yoshie
    Nakaoka, Ryusuke
    Haishima, Yuji
    Yudasaka, Masako
    Iijima, Sumio
    Tsuchiya, Toshie
    Development of an in vitro screening method for safety evaluation of nanomaterials2009In: Bio-medical materials and engineering, ISSN 0959-2989, E-ISSN 1878-3619, Vol. 19, no 1, p. 19-27Article in journal (Refereed)
    Abstract [en]

    To evaluate the role of particle size in cytotoxicity tests of nanomaterials (NMs), we exposed Chinese hamster cells to polystyrene (PS) spheres with defined diameters ranging from 0.1 to 9.2 mu m. We found that the 4.45-mu m PS particles were most cytotoxic while sizes 0.1 and 0.2 mu m showed no cytotoxicity up to 1000 mu g/ml. In the chromosome aberration test, the 4.45-mu m PS particles induced polyploidy in amass concentration-dependent manner in 24- and 48-h treatments. The 5.26-mu m PS particles induced polyploidy only at 1000 mu g/ml for 48 h. Next, we performed the cytotoxicity test with as-grown single walled carbon nanohorns (NHas). These were suspended in DMSO and then transferred into the culture medium followed by sonication. Six suspensions differently sonicated showed the same apparent toxicity, although the total particle size distributions differed. However, the sizes of NHas particles predicted to be most toxic from the experiments with PS particles, i.e. 1.01-4.47 mu m constituted 40-60% of all particles in all six suspensions. The results suggest that the cytotoxicity of NMs in suspension depends on specific sizes of aggregates and therefore suspensions should be checked with regard to particle size distributions in assays of toxic effects. The uptake of particles into cells was confirmed by confocal microscopy.

  • 108. Meijer, Lisethe
    et al.
    Brouwer, Baram
    de Jong, Frank H.J.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Sauer, Pieter J.J.
    Influence of prenatal exposure to selected organohalogans on infant sexual and neurological development2008Conference paper (Refereed)
  • 109. Meijer, Lisethe
    et al.
    Weiss, Jana
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    van Velzen, Martin
    Abraham, Brouwer
    Bergman, Åke
    Sauer, Pieter J.J.
    Serum concentrations of neutral and phenolic organohalogens in pregnant women and their infants in The NetherlandsManuscript (Other academic)
  • 110. Meijer, Lisethe
    et al.
    Weiss, Jana
    Van Velzen, Martin
    Brouwer, Abraham
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Sauer, Pieter J J
    Serum concentrations of neutral and phenolic organohalogens in pregnant women and some of their infants in The Netherlands.2008In: Environ Sci Technol, ISSN 0013-936X, Vol. 42, no 9, p. 3428-33Article in journal (Refereed)
    Abstract [en]

    As part of a large European Union (EU)-funded comparative toxicology and human epidemiology study, EU-Compare, a selection of organohalogen compounds (OHCs) was analyzed in maternal serum, collected at the 35th week of pregnancy, and in cord serum of a number of their infants to determine maternal concentrations and to investigate the extent of transplacental transfer of these compounds. Eight neutral OHCs were analyzed: one polychlorinated biphenyl (PCB: CB-153),4,4'-DDE, five polybrominated diphenyl ethers (PBDEs: BDE-47, BDE-99, BDE-100, BDE-153, and BDE-154), and hexabromocyclododecane (HBCDD). Five phenolic OHCs were analyzed: three hydroxylated PCBs (40H-CB-107, 40H-CB-146, and 40H-CB-187), one hydroxylated PBDE (60H-BDE-47), and pentachlorophenol (PCP). All OHCs, except 60H-BDE-47, were present in maternal and cord serum. The historically identified OHCs showed the highest concentration: 4,4'-DDE (median value 89 ng/g lipid in maternal serum and 68 ng/g lipid in cord serum) and PCP (median value 970 pg/g serum in maternal serum and 1500 pg/g serum in cord serum). HBCDD and the PBDEs were present at much lower concentrations. We conclude that OHCs are present in the serum of pregnant women, and all compounds tested are transferred over the placenta. Because transfer is occurring at a critical stage of infant development, investigation of the health impact is urgent.

  • 111.
    Moreira Bastos, Patricia
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Comparison of experimentally and theoretically determined oxidation and photochemical transformation rates of some organohalogens to promote prediction of persistence2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The diversity of choices we have to make everyday influence our environment and ourselves in more ways than most of us realise. Anthropogenic substances, such as flame retardants, date back as early as 450 BC when the Egyptians used alum to reduce flammability. The increasing demand for new articles has led to an increased production of chemical substances, for which many are commercially produced without complete knowledge on properties such as persistence, bioaccumulation and toxicology (PBT). Commercial compounds may be properly tested and denominated as “safe” regarding PBT properties, but their degradation products and/or metabolites may cause environmental impact.

    The availability of uniform and accurate data for prediction of persistence is of key importance for the understanding of chemical fate. A method to determine the susceptibility of chemicals to undergo oxidation in water has been developed and applied on several organohalogens, including PBDEs and OH-PBDEs. The method was used to determine reaction rates and the group of OH-PBDEs were subsequently subjected to photolysis by use of UV-light. Hence, susceptibility to undergo both oxidation and photolysis for the OH-PBDEs were investigated and compared to previously reported degradation rates on PBDEs.

    As a final step in promoting the prediction of persistence, Quantitative structure-property relationship (QSPR) models were performed on a set of compounds which had undergone photolytic degradation under similar conditions. The QSPRs were used as a preliminary step in predicting photolysis half-lives for chemical substances and to determine which physicochemical descriptors are of greatest importance thereof.

    This thesis presents the possibility of performing and assessing oxidation transformations on compounds of low and high water solubility, photolysis transformations in various media and using obtained data to predict behaviour via QSPR models, to promote predictions of persistence.

  • 112.
    Moreira Bastos, Patricia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Eriksson, Johan
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Photochemical decomposition of dissolved hydroxylated polybrominated diphenyl ethers under various aqueous conditions2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 77, no 6, p. 791-797Article in journal (Refereed)
  • 113.
    Moreira Bastos, Patricia
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Eriksson, Johan
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Vidarson, Jenny
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Oxidative transformation of polybrominated diphenyl ether congeners (PBDEs) and of hydroxylated PBDEs (OH-PBDEs)2008In: Environmental science and pollution research international, ISSN 0944-1344, E-ISSN 1614-7499, Vol. 15, no 7, p. 606-613Article in journal (Refereed)
    Abstract [en]

    BACKGROUND, AIM, AND SCOPE: The historical and widespread use of polybrominated diphenyl ethers (PBDEs) as flame retardants in consumer products worldwide has caused PBDEs to now be regarded as pervasive environmental contaminants. Most recently, hydroxylated PBDEs (OH-PBDEs) and methoxylated PBDEs (MeO-PBDEs) have emerged as environmentally relevant due to reports of their natural production and metabolism. An important parameter for assessing the environmental impact of a chemical substance is persistence. By formulating the concept that persistence is the result of the substance's physicochemical properties and chemical reactivity, Green and Bergman have proposed a new methodology to determine the inherent persistence of a chemical. If persistence could be predicted by straightforward methods, substances with this quality could be screened out before large-scale production/manufacturing begins. To provide data to implement this concept, we have developed new methodologies to study chemical transformations through photolysis; hydrolysis, substitution, and elimination; and via oxidation. This study has focused on adapting an oxidative reaction method to be applicable to non-water soluble organic pollutants. MATERIALS AND METHODS: PBDEs and one MeO-PBDE were dissolved in tetrahydrofuran/methanol and then diluted in alkaline water. The OH-PBDEs were dissolved in alkaline water prior to reaction. The oxidation degradation reaction was performed at 50 degrees C using potassium permanganate as described elsewhere. The pH was maintained at 7.6 with disodium hydrogen phosphate and barium hydrogen phosphate, the latter also serving as a trapping agent for manganate ions. The oxidation reactions were monitored by high-performance liquid chromatography and reaction rates were calculated. RESULTS: The OH-PBDEs have very fast oxidative transformation rates compared to the PBDEs. The reaction rates seem to be primarily dependent on substitution pattern of the pi-electron-donating bromine substituents and of bromine content. There are indications that further reactions of OH-PBDEs, e.g., methylation to the MeO-PBDEs, decrease the oxidation rates, and thereby generate more persistent substances. DISCUSSION: The resistance of PBDEs to oxidation, a major degradation pathway in air, should be further investigated, since these compounds do undergo long range transport. With slight modifications, the original method has been adapted to include a larger variety of chemical substances, and preliminary data are now available on the oxidative transformation rates for PBDEs and of OH-PBDEs. CONCLUSIONS: The original oxidation degradation method can now include non-water soluble compounds. This modification, using low concentrations of test chemicals, allows us to measure oxidative transformation rates, for some of the lower brominated DEs, data that can be used to assess their persistence in future model calculations. Oxidative transformation rates for PBDEs are slow compared to those for the OH-PBDEs. This suggests that OH-PBDEs, when released into the environment, undergo faster oxidative metabolism and excretion than the PBDEs. RECOMMENDATIONS AND PERSPECTIVES: To evaluate the modified method, more degradation reactions with non-water soluble compounds should be investigated. Recent studies show that OH-PBDEs are present in rats and in humans and, because of their activity as endocrine disruptors, determining their subsequent environmental fate is of importance. The resistance of PBDEs to oxidative degradation should be acknowledged as of possible future concern. Several other compound classes (such as polychlorinated biphenyls (PCBs), hydroxylated polychlorinated biphenyls (OH-PCBs), and pharmaceuticals) need to be subjected to this screening method to increase the database of transformation rates that can be used with this model.

  • 114.
    Motwani, Hitesh
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Fred, Charlotta
    Haglund, Johanna
    Golding, Bernard
    Törnqvist, Margareta
    Cob(I)alamin as an analytical tool to study 1,3-butadiene metabolism in human, mouse and rat S9 liver fractions2007In: Gordon Research Conference on Vitamin B12 and Corphins, 2007Conference paper (Other (popular science, discussion, etc.))
  • 115.
    Motwani, Hitesh
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Shimakoshi, Hisashi
    Hisaeda, Yoshio
    Golding, Bernard
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Reductive dechlorination of sucralose mediated by vitamin B12 derivatives2008Conference paper (Other academic)
  • 116.
    Motwani, Hitesh V
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Fred, Charlotta
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Haglund, Johanna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Golding, Bernard T
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Cob(I)alamin for trapping butadiene epoxides in metabolism with rat S9 and for determining associated kinetic parameters2009In: Chemical Research in Toxicology, ISSN 0893-228X, E-ISSN 1520-5010, Vol. 22, no 9, p. 1509-1516Article in journal (Refereed)
    Abstract [en]

    The reduced state of vitamin B(12), cob(I)alamin, acts as a supernucleophile that reacts ca. 10(5) times faster than standard nucleophiles, for example, thiols. Methods have been developed for trapping electrophilically reactive compounds by exploiting this property of cob(I)alamin. 1,3-Butadiene (BD) has recently been classified as a group 1 human carcinogen by the International Agency for Research on Cancer (IARC). The carcinogenicity of BD is considered to be dependent on the activation or deactivation of the reactive metabolites of BD, that is, the epoxides (oxiranes) 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB), and 1,2-epoxy-3,4-butanediol (EBdiol). Cytochrome P450 (P450) isozymes are involved in oxidation of BD to EB and further activation to DEB. EB and DEB are hydrolyzed by epoxide hydrolases (EH) to 3,4-dihydroxy-1-butene (BDdiol) and EBdiol, respectively. EBdiol can also be formed by oxidation of BDdiol. In the present study, cob(I)alamin was used for instant trapping of the BD epoxide metabolites generated in in vitro metabolism to study enzyme kinetics. The substrates EB, DEB, and BDdiol were incubated with rat S9 liver fraction, and apparent K(m) and apparent V(max), were determined. The ratio of conversion of EB to DEB (by P450) to the rate of deactivation of DEB by EH was 1.09. Formation of EBdiol from hydrolysis of DEB was ca. 10 times faster than that from oxidation of BDdiol. It was also found that the oxidation of EB to DEB was much faster than that of BDdiol to EBdiol. The study offers comparative enzyme kinetic data of different BD metabolic steps, which is useful for quantitative interspecies comparison. Furthermore, a new application of cob(I)alamin was demonstrated for the measurement of enzyme kinetics of compounds that form electophilically reactive metabolites.

  • 117. Naruszewicz, Marek
    et al.
    Zapolska-Downar, Danuta
    Kosmider, Anita
    Nowicka, Grazyna
    Kozlowska-Wojciechowska, Malgorzata
    Vikström, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Chronic intake of potato chips in humans increases the production of reactive oxygen radicals by leukocytes and increases plasma C-reactive protein: a pilot study.2009In: Am J Clin Nutr, ISSN 0002-9165Article in journal (Other academic)
    Abstract [en]

    BACKGROUND: Relatively high concentrations of acrylamide in commonly ingested food products, such as French fries, potato chips, or cereals, may constitute a potential risk to human health. OBJECTIVE: The objective of this pilot study was to investigate the possible connection between chronic ingestion of acrylamide-containing potato chips and oxidative stress or inflammation. DESIGN: Fourteen healthy volunteers (mean age: 35 y; 8 women and 6 smokers of >20 cigarettes/d) were given 160 g of potato chips containing 157 mg of acrylamide daily for 4 wk. RESULTS: An increase in acrylamide-hemoglobin adducts in blood was found in all the study subjects, with a mean of 43.1 pmol/L/g hemoglobin (range: 27-76; P < 0.01) in nonsmokers and 59.0 pmol . L(-1) . g(-1) hemoglobin (range: 43-132; P < 0.05) in smokers. Concurrently, a significant increase (P < 0.01) in the oxidized LDL, high-sensitivity interleukin-6, high-sensitivity C-reactive protein, and gamma-glutamyltransferase concentrations was observed in both smokers and nonsmokers. A significant increase in reactive oxygen radical production by monocytes, lymphocytes, and granulocytes and an increase in CD14 expression in macrophages (P < 0.001) were found after intake of potato chips. Twenty-eight days from the discontinuation of the experiment, the variables under study decreased to some extent. It has been shown also that acrylamide increases the production of reactive oxygen species in isolated human monocyte-macrophages in vitro and decreases the cellular glutathione concentration. CONCLUSION: These novel findings seem to indicate that chronic ingestion of acrylamide-containing products induces a proinflammatory state, a risk factor for progression of atherosclerosis.

  • 118.
    Norström, Karin
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bis(4-chlorophenyl) sulfone and PCB methyl sulfone metabolites: Trends and chirality in the Baltic Sea environment2006Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Baltic Sea was earlier identified as a highly polluted brackish water body and still is. The high concentrations of polychlorinated biphenyls (PCBs), p,p’-DDT and related compounds led to severe effects on several species in the Baltic region. However, the situation has improved significantly since the 1970’s resulting in lower exposures to a range of pollutants and healthier wildlife populations. Independent of this positive trend there are still new chemicals leaking into the Baltic Sea environment. The objective of this thesis is to improve the knowledge of sulfone containing compounds and pollutant metabolites in wildlife, with special interest in bis(4-chlorophenyl) sulfone (BCPS) distribution, temporal trend and exposure levels, and the methylsulfonyl-PCBs (MeSO2-PCBs). The latter are of particular interest for chiral MeSO2-PCBs. BCPS is used for the production of high temperature polymers and was detected as an environmental contaminant ten years ago. PCBs, p,p’-DDT and related compounds are still of scientific interest.

    BCPS is biomagnified and especially in the bird guillemot which has levels of up to 2000 ng BCPS/g fat compared to the grey seal with concentrations of about 60 ng/g fat. The seal levels are similar to the herring, the prey of the bird and seal, with concentrations of 30 ng BCPS/g fat. The guillemot concentration of BCPS has been similar over the last 30 years with a minimal, but significant, annual decline of 1.6%. The reason for the slow decline is not yet understood. Also MeSO2-PCBs and 3-MeSO2-DDE show a small decrease over time in guillemot egg (3 and 9%, respectively), which is less then for the parent compounds. This shows that the sulfone metabolites are more persistent than their precursors in the guillemot. Furthermore, all these sulfone containing compounds showed a specific retention to liver comparing different tissues in grey seal. The atropisomers of the chiral MeSO2-PCB were analysed in both the guillemot and the grey seal and showed to occur in a skewed relationship. This is particularly pronounced in seals where one atropisomer of each chiral congener is very dominating. The dominating atropisomers have been identified with an absolute R configuration, in both grey seal and guillemot. An enantioselective metabolism was indicated to occur when experimentally tested by CB-132 in rat.

    This thesis is stressing the high specificity in wildlife for one atropisomer in the pair of chiral PCB methyl sulfones being PCB metabolites, and the high BCPS concentrations in guillemot hatching in the Baltic proper.

  • 119.
    Norström, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Eriksson, Johan
    Haglund, Johanna
    Silvari, Virginia
    Bergman, Åke
    Enantioselective metabolism of 2,2’,3,3’,4,6’-hexaCB in ratManuscript (Other academic)
  • 120.
    Norström, Karin
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Olsson, Anders
    Olsson, Mats
    Bergman, Åke
    Bis(4-chlorophenyl) sulfone (BCPS) in Swedish marine and fresh water wildlife – a screening study2004In: Environment International, ISSN 0160-4120, Vol. 30, no 5, p. 667-674Article in journal (Refereed)
  • 121. O’Regan, M.
    et al.
    Moran, K.
    Backman, Jan
    Stockholm University, Faculty of Science, Department of Geology and Geochemistry.
    King, J.
    Jakobsson, Martin
    Department of Environmental Chemistry.
    Integrating Recent Pleistocene Glacial Records From the Lomonosov Ridge, Central Arctic Ocean2005In: EOS Transactions, American Geophysical Union, v. 86(52): Fall Meet. Suppl.,, 2005, p. Abstract PP43C-04Conference paper (Other academic)
  • 122. Park,, Hye-Youn
    et al.
    Park,, June-Soo
    Sovcikova, Eva
    Kocan, Anton
    Linderholm, Linda
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Trnovec, Tomas
    Hertz-Picciotto, Irva
    Exposure to Hydroxylated Polychlorinated Biphenyls (OH-PCBs) in the Prenatal Period and Subsequent Neurodevelopment in Eastern Slovakia2009In: Journal of Environmental Health Perspectives, ISSN 0091-6765, E-ISSN 1552-9924, Vol. 117, no 10, p. 1600-1606Article in journal (Refereed)
  • 123. Park, June-Soo
    et al.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Linderholm, Linda
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Kocan, Anton
    Petrik, Jan
    Drobna, Beata
    Trnovec, Tomas
    Charles, M Judith
    Hertz-Picciotto, Irva
    Placental transfer of polychlorinated biphenyls, their hydroxylated metabolites and pentachlorophenol in pregnant women from eastern Slovakia.2008In: Chemosphere, ISSN 0045-6535, Vol. 70, no 9, p. 1676-84Article in journal (Refereed)
  • 124. Park, June-Soo
    et al.
    Linderholm, Linda
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Charles, Judith
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Petrik, Jan
    Kocan, Anton
    Drobna, Beata
    Trnovec, Tomas
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Hertz-Piciotto, Irva
    Polychlorinated biphenyls and their hydroxylated metabolites (OH-PCBs) in pregnant women from east Slovakia2007In: Environmental Health Perspectives, ISSN 0091-6765, Vol. 115, no 1, p. 20-27Article in journal (Refereed)
  • 125.
    Persson, Linn
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Methods for the study of dissolved organic matter as an environmental actor2003Doctoral thesis, comprehensive summary (Other academic)
  • 126. Pérez-Maldonado, Iván N
    et al.
    Ramírez-Jiménez, María del Rocio
    Martínez-Arévalo, Laura P
    López-Guzmán, O Dania
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Yarto-Ramírez, Mario
    Gavilán-García, Arturo
    Yáñez, Leticia
    Díaz-Barriga, Fernando
    Exposure assessment of polybrominated diphenyl ethers (PBDEs) in Mexican children2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 75, no 9, p. 1215-1220Article in journal (Refereed)
    Abstract [en]

    Flame retardants (FRs) constitute a group of compounds that are added to materials in order to suppress, reduce, or delay fire. At present the most used FRs are the polybrominated diphenyl ethers (PBDEs), and diverse studies have found individuals exposed to them. However, few studies have reported data in children. The objective of this report was to assess PBDEs levels in children of six communities in México. During the year 2006 we analyzed a total of 173 healthy children (aged 6-13 years old). Plasma samples were taken and quantified (gas chromatography/mass spectrometer) for PBDEs. Six PBDEs congeners (BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, and BDE-209) were quantified in blood serum. We detected exposure to PBDEs in all the communities. The total PBDEs levels ranged from no detectable (nd) to 43.4 ng g(-1) lipid, the dominant PBDE congener was BDE-47, followed by BDE-100, BDE-99 and BDE-153, whereas the levels of BDE-209 were below LOD. Children living in an industrial and urban area (Cd. Juarez, Chih) had the highest levels of PBDEs, approximately two times that of children living in El Refugio, S.L.P. (a rural area) or in Milpillas, S.L.P. (municipal landfill) and 4-5 times higher than levels found in children living in San Luis Potosi, S.L.P. (urban area), in Chihuahua, Chih. (urban area), and San Juan Tilapa, Edo. Mex. (municipal landfills). Results cannot be generalized since the communities selected are not representative of the Mexican population. However, they do indicate that Mexican children are exposed to PBDEs.

  • 127. Qiu, Yanling
    et al.
    Eriksson, Johan
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Granelli, Lisa
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    An improved method for assessing relative nucleophilic substitution reactivities of polychlorinated benzenes2009In: Chemosphere, ISSN 0045-6535, E-ISSN 1879-1298, Vol. 75, no 1, p. 78-82Article in journal (Refereed)
    Abstract [en]

    An existing substitution reaction method was improved as part of a system to measure the persistency of selected chemicals in the environment by evaluating their chemical reactivity. Hexachlorobenzene (HCB), pentachlorobenzene, 1,2,4,5-tetrachlorobenzene and 1,2,4-trichlorobenzene were selected as model compounds. Sodium methoxide in methanol was used as a nucleophile and found to be stable for at least 35 days after preparation. The substitution reaction system was modified so that nitrogen protection was not necessary to avoid oxidation and hydrolysis effects, which led to improved results. The reactivity of polychlorinated benzenes (PCBz), which substituted chlorine for methoxide according to a second-order rate constant, increased as the number of chlorine atoms on the benzene ring increased. HCB was selected as a standard for the k2 calculations of the substitution reactions. A normalized k2 (kN) was calculated as kN = kPCBz/kHCB. GC–MS analysis confirmed that the reactions were pure nucleophilic aromatic substitutions without side reactions.

  • 128.
    Rahm, Sara
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Hydrolysis and photolysis of brominated flame retardants and some traditional persistent organic pollutants: Reactivity as a tool in fate assessement of chemicals2004Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    An organic compound that remains in the environment for a long time is regarded as a persistent organic pollutant (POP). Still, persistency is not a well defined property with a firm definition. Instead it is a conceptual property of chemicals for which DDT and PCB are typical representatives. No organic chemicals in the environment are inert and are thus subjected to chemical transformation reactions in air, water, soil sediments and in biota. Environmental pollutants are distributed in the environment based on their physicochemical properties and their reactivity. While the former properties have been thoroughly studied and used in modelling of the fate of chemicals in the environment, the latter property – reactivity – has been investigated poorly.

    The far-reaching objective with the present thesis is to introduce the reactivity of chemicals into the concept of persistency. More specifically the aim is to develop methodologies for defining chemical reactivity by determination of disappearance reaction constants for hydrolysis and photolysis of actual or potential environmental contaminants. Other transformation reactions in the environment such as oxidations reductions and radical reactions are not included at this stage. In this thesis, hydrolysis include both substitution and elimination reactions. The developmental work is performed largely by comparing the reactivity of brominated flame retardants but also include several traditional contaminants for comparative reasons.

    A new method for determination of the rate of hydrolysis of chemicals is developed using methoxide in methanol and DMF, which is done by using hexachlorobenzene (HCB) as the test chemical. The method is applied to several other chemicals, particularly polybrominated diphenyl ethers (PBDEs) but also traditional POPs. Chemicals such as DDT,TBBPA 2,3-dibromopropyl ether react very fast and the perbrominated diphenyl ether (BDE-209) is shown to undergo nucleophilic aromatic substitution faster than HCB. Compounds that can undergo elimination are rapidly degraded while the rates of substitution reactions of aromatic chemicals depend on the degree of halogenation.

    A new method is used for studying photolytic reactions based on irradiation of UV light at environmentally relevant wavelengths and with the study compounds dissolved in methanol/water (4:1). Disappearance constants and quantum yields are determined for several traditional and potential environmental contaminants. Halogenated phenols are rapidly transformed under these conditions. Polybrominated aromatics are indicated to react faster than the corresponding chlorinated compounds.

    The two methods for studying reactivity of chemicals have the potential of being useful to predict the persistency of chemicals in the environment. Such predictions must however also include the compound’s susceptibility to oxidation, reduction and radical reactions in all major environmental compartments and knowledge of their physicochemical characteristics.

  • 129.
    Rahm, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Green, Nicholas
    Eriksson, Johan
    Bergman, Åke
    Photochemical degradation rates and quantum yields of both typical and potential environmental contaminantsManuscript (Other academic)
  • 130.
    Rahm, Sara
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Green, Nicholas
    Norrgran, Jessica
    Bergman, Åke
    Nucleophilic displacement and elimination reactions as a measure of chemical hydrolysis of environmental contaminantsManuscript (Other academic)
  • 131. Rydberg, Per
    et al.
    Eriksson, Sune
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Tareke, Eden
    Karlsson, Patrik
    Ehrenberg, Lars
    Törnqvist, Margareta
    Investigations of factors that influence the acrylamide content of heated foodstuffs2003In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, Vol. 51, p. 7012-7018Article in journal (Refereed)
  • 132.
    Rydén, Andreas
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Nestor, Gustav
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Cuadra, Steven N
    Jakobsson, Kristina
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Synthesis and identification of hydroxylated polybrominated diphenyl ethers in human blood 2009In: Organohalogen Compounds, Vol. 71, Peking, 2009, p. 2044-2048Conference paper (Refereed)
  • 133.
    Sandholm, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Metabolism of some polychlorinated biphenyl and polybrominated diphenyl ether congeners in the rat2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [sv]

    For the understanding of the metabolic fate of xenobiotics, in vivo studies are needed. In this thesis the metabolism of CB-28 and CB-77 and BDE-209 in the rat are determined. In addition, pharmacokinetic studies of CB-28 and BDE- 209 are included. The compounds were radiolabelled and their excretion and tissue distribution determined. The metabolites were characterised by their behaviour in the clean-up steps. The analysis of non-conjugated metabolites was performed by GC/MS. For other metabolites, HPLC with radioactivity monitoring and LC/MS were used for the characterisation. The absorption of BDE-209 has previously been reported to be low, <1%. In this work the bioavailability of BDE-209 was determined to be as high as 26% and strong indications that its absorption was even higher. Lipophilic compounds are generally distributed to lipid-rich tissues. CB-28 was rapidly distributed to adipose tissue, which over time had the highest concentration. BDE-209 was not readily distributed to adipose tissue, the liver and plasma showing the highest concentrations instead. Selective distribution can be explained by selective affinity for certain tissue proteins. Orthohydroxylated CB-28 metabolite was selectively retained in the brain. There were indications that hydroxylated BDE-209 metabolites were selectively retained in plasma. The terminal half-life of BDE-209 in rat plasma was 57 h and metabolism and faecal excretion the major routes of elimination.

    Common for all compounds was that the metabolic pathway included reactive metabolites. Non-extractable, water-soluble and lipid-bound metabolites were also found. For CB-77, the lipid-bound metabolites were studied and these were shown to be associated to polar lipids, e.g. phospholipids. There were indications that they were formed in the liver.

    In conclusion, this thesis discusses the metabolism of two PCB congeners and BDE-209. The importances of metabolism studies are emphasised for risk assessment and the understanding of levels in biota. The clearance, metabolism and distribution of a compound are essential for an understanding of biological and toxicological effects.

  • 134. Scheringer, M
    et al.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Fiedler, H
    Holoubek, I
    Suzuki, N
    Zetzsch, C
    The international panel on chemical pollution (IPC):2007In: 11th International Conference on Chemistry and the Environment: Chemistry, environment & human activity in civilization development, 2007, p. 193-Conference paper (Other academic)
  • 135. Scheringer, M
    et al.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Fiedler, H
    Holoubek, I
    Suzuki, N
    Zetzsch, C
    The international panel on chemical pollution (IPCP): Background and perspectives2007In: Organohalogen Compounds: Dioxin 2007, 2007, p. 528-531Conference paper (Refereed)
  • 136. Scheringer, Martin
    et al.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    International panel on chemical pollution2009Other (Other (popular science, discussion, etc.))
  • 137. Sjödin, Andreas
    et al.
    Carlsson, Håkan
    Thuresson, Kaj
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Sjölin, Sverker
    Bergman, Åke
    Östman, Conny
    Flame retardants in indoor air at an electronics recycling plant and at other work environments2001In: Environmental science & technology, ISSN 0013-936X, Vol. 35, no 3, p. 448-454Article in journal (Refereed)
  • 138.
    Soechitram, Shalini
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanasiadou, Maria
    Hovander, Lotta
    Bergman, Åke
    Sauer, Pieter
    Fetal exposure to PCBs and their hydroxylated metabolites in a Dutch Cohort2004In: Environmental Health Perspectives, ISSN 0091-6765, Vol. 112, no 11, p. 1208-1212Article in journal (Refereed)
  • 139.
    Strid, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanassiadis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Svavarsson, Jörundur
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Brominated organic compounds in a high trophic Arctic fish species, Greenland shark (Somniosus microcephalus)2008In: 6:e Svensk-norskt miljökemiskt möte: SNMM 2008 22-24 September, 2008Conference paper (Other (popular science, discussion, etc.))
  • 140.
    Strid, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanasiadou, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Athanassiadis, Ioannis
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Svavarsson, Jörundur
    Bergman, Åke
    Brominated organic compounds in a high trophic arctic fish species, Greenland shark (Somniosus microcephalus)2008In: Organohalogen Compounds: pops in marine mammals: Levels, effects, trends, 2008, p. 817-820Conference paper (Refereed)
  • 141.
    Strid, Anna
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Jörundsdóttir, Hrönn
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Päpke, Olaf
    Eurofins-ERGO Research, Geierstrasse 1, D-223 05 Hamburg, Germany.
    Svavarsson, Jörundur
    Institute of Biology, University of Iceland, IS-101 Reykjavík, Iceland.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Dioxins and PCBs in Greenland shark (Somniosus microcephalus) from the North-East Atlantic2007In: Marine Pollution Bulletin, ISSN 0025-326X, E-ISSN 1879-3363, Vol. 54, no 9, p. 1514-1522Article in journal (Refereed)
    Abstract [en]

    The Greenland shark (Somniosus microcephalus) is a high-trophic fish species present in Arctic waters. The present study aimed to determine concentrations of polychlorinated dibenzo-p-dioxins and furans (PCDDs/Fs), dioxin-like (DL) PCBs and six non-dioxin-like (NDL) PCBs in muscle and liver from 10 female Greenland sharks collected between 2001 and 2003 from Icelandic waters. The mean total concentrations of PCDDs/Fs were 13 and 530 pg/g fat for muscle and liver, respectively, and show enrichment in the liver. Concentrations of DL-non-ortho PCBs were also higher in liver compared to muscle with mean concentrations of 7.8 and 0.36 ng/g fat, respectively. No enrichment in the liver was found for DL-mono-ortho- and NDL-PCBs. No correlation was found between the size range studied and total concentrations of the compounds analyzed. Total WHO-TEQs (PCDDs/Fs and DL-PCBs) ranged between 7.1–70 and 54–1500 pg/g fat in muscle and liver, respectively.

  • 142.
    Sundström, Maria
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Hart, J, A
    Chang, S, C
    Ehresman, D, J
    Gorman, G., S.
    Noker, P, E
    Olsen, G, W
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Butenhoff, J, L
    Comparative pharmacokinetics of perfluorohexanesulfonate (PFHxS) in rats and monkeys 2009In: Organohalogen Compounds, Vol. 71, Peking, 2009, p. 1191-1196Conference paper (Refereed)
  • 143.
    Söderström, Maria
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Local and global contaminants in Swedish waters: studies on PCBs, DDTs, 4,5,6-trichloroguaiacol and their transformation products in fish and sediments2002Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    This thesis is focused on studies on the environmental fate and methodological improvements for determination of the global contaminants, PCBs and DDTs, and locally discharged phenolics, e.g. 4,5,6-trichloroguaiacol (4,5,6-TCG), and their transformation products.

    4,5,6-TCG is released from bleached pulp mills, and was chosen as a model substance, to study its fate and effects in aquatic environments. In a brackish water model ecosystem, 4,5,6-TCG was shown to be transformed via demethylation, dechlorination, and methylation reactions. Marine periphyton exposed to 4,5,6-TCG was shown to form demethylated, brominated and dimeric metabolites. Several of these metabolites were identified and quantified. Also more tightly bound chlorophenolics were recovered from the substrate, after harsh extraction procedures had been applied. Conjugates of chlorophenols in fish bile were determined as useful tracers for monitoring effluents from bleached pulp mills, even in areas far from the discharge point. To facilitate calculations of water concentrations, bile to water bioconcentration factors (bBCF-values) were determined for several phenolics, including also alkali-labile chlorocatechols.

    PCBs and DDTs, were assessed in Swedish lakes with background exposure of these global contaminants. A methodological study focus on the contamination risks of airborne PCBs, during freeze-drying and storage of dry sediment samples. Eutrophication has been proposed to cause lower levels of pollutants in biota in lakes due to biomass dilution but in this thesis examples of higher levels of PCBs in sediment traps, sediment and in perch, and also in higher fluxes of PCBs to the sediment, were observed. Phytoplankton are supposed to be responsible for most of the transport of the contaminants. The composition of DDTs in soil, sediment traps and in dated sediment cores was studied in some detail. PCBs, DDTs, HCB and HCHs were measured in sediments from 100 reference lakes included in the National Swedish Environmental Program. The lakes have a large variation in lake characteristics, representative for different areas in Sweden. A gradient was observed for sPCB with decreasing levels from the south west towards the north. The results suggests that longrange transport is the dominating mechanism for distribution of the contaminants analysed. In this study the levles of PCBs and DDTs were lower in eutrophic lakes than in oligotrophic lakes, in an area with similar atmospheric exposure.

  • 144.
    Tareke, Eden
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Identification and origin of potential background carcinogens: endogenous isoprene and oxiranes, dietary acrylamide2003Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The primary aims of this thesis are to discover carcinogens in the general population by identification of products of reaction with hemoglobin (Hb adducts) in blood from humans without known exposure, and tracing the origin of the adducts. Chemicals and/or their metabolites forming Hb adducts mostly also react with DNA and may thus cause mutations, a key event in carcinogenesis. Factors, that may affect in vivo doses, that is cooking of food, degree of unsaturation of dietary fatty acids, and intestinal micro-flora, were investigated. Analysis of adducts to N-termini in Hb, by gas chromatography-tandem mass spectrometry (GC/MS-MS), was applied as a tool.

    Due to large endogenous production of isoprene the in vivo formation of reactive monoepoxides was studied. Two adducts originating from the monoepoxides were identified in rodents exposed to isoprene or isoprene monoepoxides. Relatively high in vivo doses of monoepoxides were found in mice compared to rats after treatment with isoprene, although the detoxification rates were about equal in both species. Despite an effective metabolism to monoepoxides as shown in the mouse, corresponding background adduct levels were very low in both rodents and humans, probably showing a very low cancer risk increment from endogenous isoprene.

    Hb adduct levels signify ubiquitous background doses of the mutagens/carcinogens ethylene oxide (EO) and propylene oxide (PO) in humans. Levels of these adducts were earlier shown to be lower in germ-free (GF) than in conventional (CV) mice. Detoxification was shown to be faster in CV mice, but, evidently due to still faster production the in vivo doses of EO and PO were higher in CV than in GF mice. The influence of unsaturated fatty acids was small. Formation of EO and PO and also of a peroxidation indicator in GF mice, that is in the absence of micro-flora, points towards ethene and propene, peroxidatively formed in tissues, being the precursors of the oxiranes. The same mechanism, amplified by changes of the host metabolism caused by the microflora, occurs also in CV animals.

    Background Hb adducts from acrylamide show a general occurrence, in humans at levels possibly associated with a relatively high cancer risk. Acrylamide is present in tobacco smoke. In wild animals lower adduct levels than in humans are observed. These facts indicate a role of cooking in acrylamide exposure, a hypothesis tested in animal feeding experiments. Rats fed heated feed showed increase of several adducts including un about 10 times increase of the adduct levels from acrylamide, identified by MS-MS in comparison with authentic standards, with confirmation by analysis of acrylamide in heated feed. In follow-up studies with heated foods, high acrylamide formation was found in carbohydrate-rich foodstuffs as compared to low levels in protein foods. Acrylamide was formed above 120°C in a temperature-dependent manner.

    These studies give support to the use of Hb adducts for the detection and identification of endogenous and exogenous genotoxic factors which are potential contributors to background cancer incidence, and for identification of determinants of their in vivo doses.

  • 145. Tareke, Eden
    et al.
    Rydberg, Per
    Karlsson, Patrik
    Eriksson, Sune
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Törnqvist, Margareta
    Analysis of acrylamide, a carcinogen formed in heated foodstuffs2002In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, Vol. 50, p. 4998-5006Article in journal (Refereed)
  • 146.
    Teclechiel, Daniel
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Synthesis and characterization of highly polybrominated diphenyl ethers2008Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Polybrominated diphenyl ethers (PBDEs) make up an important class of brominated flame retardants. The present production is mainly concentrated to DecaBDE but until recently also a significant production of PentaBDE and OctaBDE took place, leaving us with a large number of different PBDE congeners. The PBDEs have become widespread pollutants abiotically and in biota, particularly in high trophic level wildlife and in humans. Accordingly, pure authentic reference standards have been required to promote high quality exposure assessments of wildlife and humans and analysis of abiotic matrices, to study both chemical and physical properties of the PBDEs and to allow toxicological studies. The objective of this thesis was to develop methods for synthesis of polybrominated diphenyl ether (PBDE) congeners and to characterize them. Further, some octabrominated DEs were determined with x-ray crystallography. Main focus has been to prepare highly brominated PBDE congeners, i.e. PBDEs substituted with six to nine bromine atoms.

    A total number of twenty-three PBDE congeners were synthesized via reduction of decabromodiphenyl ether receiving nonaBDEs; perbromination and bromination of mono- and diaminodiphenyl ethers followed by diazotization of the amino group(s) and reduction of the diazonium ion(s) receiving octaBDEs and nonaBDEs; selective bromination of diaminodiphenyl ethers followed by diazotization of the amino groups and insertion of bromine receiving hexaBDEs and heptaBDEs; bromination of the latter PBDEs giving octaBDEs; and an improved coupling of symmetrical diphenyliodonium salts with bromophenols yielding tetraBDEs to octaBDEs. To enable these compounds to be synthesized three hexabromodiphenyl iodonium salts were prepared: 2,2’,3,3’,4,4’-, 2,2’,4,4’,5,5’- and 2,2’,4,4’,6,6’ - hexabromodiphenyliodonium salts. These iodonium salts are described for the first time which made it possible to synthesize PBDE congeners with 2,3,4-, 2,4,5- and 2,4,6-tribromo substitution in the phenyl rings originating from the diphenyliodonium salts. Among the PBDE congeners 18 are synthesized for the first time. The thesis includes an improved methodology for synthesis of polybromodiphenyl iodonium salts which is based on improved solubilization of both one of the reactants and the product formed. The present work on PBDE synthesis adds useful methods for synthesis of the most highly brominated diphenyl ether congeners.

  • 147.
    Teclechiel, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Christiansson, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Synthesis of octabrominated diphenyl ethers from aminodiphenyl ethers2007In: Environmental Science & Technology, Vol. 41, no 21, p. 7459-7463Article in journal (Refereed)
    Abstract [en]

    Polybrominated diphenyl ethers (PBDEs) are additive brominated flame retardants (BFRs), which have become widespread pollutants in abiotic and biotic environments including man. Tetra- to hexaBDEs and decaBDE are the most common environmental PBDE contaminants. Congeners of octabromodiphenyl ethers (octaBDEs) originate from used industrial OctaBDE mixtures and from transformation products of the high-volume industrial BFR mixture "DecaBDE", which most exclusively consists of perbrominated diphenyl ether (BDE-209). The objective of the present work was to develop methods for the synthesis of authentic octaBDE congeners in order to make them available as standards for analytical, toxicological, and stability studies, as well as studies concerning physical-chemical properties. The syntheses of six octaBDEs, 2,2',3,3',4,4',5,5'-octabromodiphenyl ether (BDE-194), 2,2',3,3',4,4',5,6'-octabromodiphenyl ether (BDE-196), 2,2',3,3',4,5,5',6-octabromodiphenyl ether (BDE-198), 2,2',3,3',4,5',6,6'-octabromodiphenyl ether (BDE-201), 2,2',3,3',5,5',6,6'-octabromodiphenyl ether (BDE-202), and 2,2',3,4,4',5,6,6'-octabromdipheny ether (BDE-204), are described, of which BDE-204 was prepared via two different pathways. Syntheses of BDE-198, BDE-201, BDE-202, and BDE-204 are based on octabromination of mono- or diaminodiphenyl ethers followed by diazotization and reduction of the amino group(s). BDE-194 and BDE-196 were prepared by bromination of 3,3',4,4',5,5'-hexabromodiphenyl ether (BDE-169) and 2,3,3',4,4',5',6-heptabromodiphenyl ether (BDE-191), respectively, and BDE-169 and BDE-191 were prepared from 4,4'-diaminodiphenyl ether and 3,4'-diamiodiphenyl ether, respectively. The synthesized PBDE congeners are described by 1H NMR, 13C NMR, electron ionization mass spectra, and their melting points.

  • 148.
    Teclechiel, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Christiansson, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Synthesis of octabrominated diphenyl ethers from aminodiphenyl ethers2007In: Environmental Science and Technology, Vol. 41, no 21, p. 7459-7463Article in journal (Refereed)
    Abstract [en]

    Polybrominated diphenyl ethers (PBDEs) are additive brominated flame retardants (BFRs), which have become widespread pollutants in abiotic and biotic environments including man. Tetra- to hexaBDEs and decaBDE are the most common environmental PBDE contaminants. Congeners of octabromodiphenyl ethers (octaBDEs) originate from used industrial OctaBDE mixtures and from transformation products of the high-volume industrial BFR mixture "DecaBDE", which most exclusively consists of perbrominated diphenyl ether (BDE-209). The objective of the present work was to develop methods for the synthesis of authentic octaBDE congeners in order to make them available as standards for analytical, toxicological, and stability studies, as well as studies concerning physical-chemical properties. The syntheses of six octaBDEs, 2,2',3,3',4,4',5,5'-octabromodiphenyl ether (BDE-194), 2,2',3,3',4,4',5,6'-octabromodiphenyl ether (BDE-196), 2,2',3,3',4,5,5',6-octabromodiphenyl ether (BDE-198), 2,2',3,3',4,5',6,6'-octabromodiphenyl ether (BDE-201), 2,2',3,3',5,5',6,6'-octabromodiphenyl ether (BDE-202), and 2,2',3,4,4',5,6,6'-octabromdipheny ether (BDE-204), are described, of which BDE-204 was prepared via two different pathways. Syntheses of BDE-198, BDE-201, BDE-202, and BDE-204 are based on octabromination of mono- or diaminodiphenyl ethers followed by diazotization and reduction of the amino group(s). BDE-194 and BDE-196 were prepared by bromination of 3,3',4,4',5,5'-hexabromodiphenyl ether (BDE-169) and 2,3,3',4,4',5',6-heptabromodiphenyl ether (BDE-191), respectively, and BDE-169 and BDE-191 were prepared from 4,4'-diaminodiphenyl ether and 3,4'-diamiodiphenyl ether, respectively. The synthesized PBDE congeners are described by 1H NMR, 13C NMR, electron ionization mass spectra, and their melting points.

  • 149.
    Teclechiel, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Christiansson, Anna
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Bergman, Åke
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Marsh, Göran
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Synthesis of Octabrominated Diphenyl Ethers from Aminodiphenyl Ethers2007In: Environ. Sci. Technol., ISSN 0013-936X, Vol. 41, no 21, p. 7459-7463Article in journal (Refereed)
    Abstract [en]

    Polybrominated diphenyl ethers (PBDEs) are additive brominated flame retardants (BFRs), which have become widespread pollutants in abiotic and biotic environments including man. Tetra- to hexaBDEs and decaBDE are the most common environmental PBDE contaminants. Congeners of octabromodiphenyl ethers (octaBDEs) originate from used industrial OctaBDE mixtures and from transformation products of the high-volume industrial BFR mixture "DecaBDE", which most exclusively consists of perbrominated diphenyl ether (BDE-209). The objective of the present work was to develop methods for the synthesis of authentic octaBDE congeners in order to make them available as standards for analytical, toxicological, and stability studies, as well as studies concerning physical-chemical properties. The syntheses of six octaBDEs, 2,2',3,3',4,4',5,5'-octabromodiphenyl ether (BDE-194), 2,2',3,3',4,4',5,6'-octabromodiphenyl ether (BDE-196), 2,2',3,3',4,5,5',6-octabromodiphenyl ether (BDE-198), 2,2',3,3',4,5',6,6'-octabromodiphenyl ether (BDE-201), 2,2',3,3',5,5',6,6'-octabromodiphenyl ether (BDE-202), and 2,2',3,4,4',5,6,6'-octabromdipheny ether (BDE-204), are described, of which BDE-204 was prepared via two different pathways. Syntheses of BDE-198, BDE-201, BDE-202, and BDE-204 are based on octabromination of mono- or diaminodiphenyl ethers followed by diazotization and reduction of the amino group(s). BDE-194 and BDE-196 were prepared by bromination of 3,3',4,4',5,5'-hexabromodiphenyl ether (BDE-169) and 2,3,3',4,4',5',6-heptabromodiphenyl ether (BDE-191), respectively, and BDE-169 and BDE-191 were prepared from 4,4'-diaminodiphenyl ether and 3,4'-diamiodiphenyl ether, respectively. The synthesized PBDE congeners are described by 1H NMR, 13C NMR, electron ionization mass spectra, and their melting points.

  • 150.
    Teclechiel, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Eriksson, Lars
    Molecular and supramolecular structure of 2,2',3,3',4,5,5',6-OctabromoDiphenyl ether (BDE-198); 2,2',3,3',4,5',6,6'-OctabromoDiphenyl ether (BDE-201); 2,2',3,3',5,5',6,6'-OctabromoDiphenyl ether (BDE-202); 2,2',3,4,4',5,5',6-OctabromoDiphenyl ether (203) and 2,2',3,4,4',5,6,6'-Octabromodiphenyl ether (BDE-204)Manuscript (Other academic)
1234 101 - 150 of 178
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf