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  • 1
    Electronic Resource
    Electronic Resource
    Coal mine workers' pneumoconiosis (1997)
    Springer
    Environmental geology 30 (1997), S. 72-80 
    Details
    ISSN: 1432-0495
    Keywords: Key words Coal mine workers' pneumoconiosis ; Coalification ; Macerals ; Organic compounds ; Phenols
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  The fibrogenic and cytotoxic potential of coal mine dust is independent of the amount of quartz and other inorganic parameters. Results of coal petrographical and organic geochemical investigations of coals and coal mine dust from the Ruhr and Ibbenbüren Region of Germany demonstrate variations of organic dust amount possibly influencing these noxious properties. Coal mine dust of high rank coals is characterized by a pronounced fibrogenic risk. This risk, independent of the quantity of quartz, is probably based on shape variations of different coal macerals. With increasing coalification of the corresponding seam, the vitrinite is enriched in its dust; however, lower concentrations have been determined for inertinite. Vitrinite shows constant shapes and sizes independent of the rank of coal. Inertinite particles with elongated to fibrous shapes tend to larger sizes with increasing coalification. Strikingly, coal mine dust from miners' lungs with high degrees of coal mine workers' pneumoconiosis (CWP) is enriched in inertinite. In contrast, high cytotoxicities in cell tests are known for coal mine dust from low coalified coals. High concentrations of phenolic compounds can be extracted by dichloromethane from low coalified coal mine dust. These compounds, which are characterized by a high water solubility and therefore high bioavailability, explain the high cytotoxicities of coal mine dust. Contamination of dust by diesel emissions in the coal mine can act as additionally supporting parameters for extended cytotoxicities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050134
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Sources and pathways of natural and anthropogenic hydrocarbons into the natural dump Arkona Basin (southern Baltic Sea) (2000)
    Springer
    Environmental geology 39 (2000), S. 839-848 
    Details
    ISSN: 1432-0495
    Keywords: Key words Baltic Sea ; Arkona Basin ; Hydrocarbons ; Transport ; Hydrocarbon sources
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  Surface sediments, suspended particulate matter and fluffy-layer material, collected in the Arkona Basin and the Pomeranian Bay during 1995–1997, as well as air particulate matter, collected on the island of Rügen during August 1995, were analysed for total organic carbon content, saturated and polycyclic aromatic hydrocarbons (PAH). The resulting concentrations and distributions of these compounds and molecular PAH ratios are discussed in terms of matrix, origin of the organic matter and seasonal variations. The data show that the Oder river can be identified as a major source for PAH transported into the southern part of the Arkona Basin. A strong atmospheric input of PAH is noted for the central and northern part of the basin. In general, anthropogenic and bacterially degraded hydrocarbons bound to organic carbon-rich and small particles are mainly deposited in the basin center, whereas their natural counterparts accumulate mainly on the basin flanks covered by coarser grained sediments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002549900038
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  • 3
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    Impact of estuarine convergence on residual circulation in tidally energetic estuaries and inlets (2014)
    Wiley-Blackwell
    Details
    Publication Date: 2014-01-04
    Description: [1]  Estuarine convergence (landward reduction of width and/or depth) is known to have the potential to significantly enhance estuarine circulation, a result theoretically derived under the assumption of constant eddy viscosity. Recent studies of longitudinally uniform energetic tidal channels indicate that tidal straining, a process driven by tidally varying eddy viscosity, is a major driver of estuarine circulation. The combined effect of estuarine convergence and tidal straining is investigated, for the first time, in this paper. The present idealized numerical study shows that estuarine convergence is weakening or even reversing tidal straining circulation in such a way that estuarine circulation can be weakened. This is a counter-intuitive hydrodynamic effect of estuarine convergence, which may reduce (rather than increase) up-estuary particulate matter transport in estuaries and tidal inlets.
    Print ISSN: 0094-8276
    Electronic ISSN: 1944-8007
    Topics: Geosciences , Physics
    Published by Wiley-Blackwell on behalf of American Geophysical Union (AGU).
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  • 4
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    Nano-Crystal Formation of Tio2 Polymorphs Brookite and Anatase Due To Organic--Inorganic Rock-Fluid Interactions (2016)
    Society for Sedimentary Geology (SEPM)
    Details
    Publication Date: 2016-03-02
    Description: :  The occurrence of the titania polymorphs brookite and anatase as nano-crystals in organic matter-rich sediments of differing age and thermal maturity has been investigated by means of a multidisciplinary analytical approach (FIB-TEM, organic geochemistry, and petrography). It was the aim of the study to analyze the formation mechanisms, fate and behavior of the titania nano-crystals as a result of organic–inorganic rock–fluid interactions. Brookite nano-crystals have been detected in immature Mediterranean sapropels of Quaternary age, but anatase also occurs in deeper and older black shales (Furongian Alum Shale, Sweden; Devonian to Carboniferous Bakken Shale, Williston Basin, USA). Whereas anatase prevails as single crystals, brookite nano-crystals often are agglomerated. Single brookite nano-crystals from Posidonia Shale (Lower Jurassic, Northern Germany) have increasing crystal diameters with increasing thermal maturity. Exclusively anatase nano-crystals both as single crystals or as agglomerates have been detected at oil–water contacts in oilfields, and along fractures with fluid flow enriched in dissolved organic carbon. Titania nano-crystal precipitation, growth (and agglomeration) takes place in the pore water of micro-environments at low to high temperatures and where low pH is coupled to the occurrence of dissolved organic components. Low sedimentation rates preserving a critical geochemical environment or higher temperatures seem major controls for the precipitation of anatase and its tendency not to agglomerate.
    Print ISSN: 1527-1404
    Topics: Geosciences
    Published by Society for Sedimentary Geology (SEPM)
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  • 5
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    Creation of pre-oil-charging porosity by migration of source-rock-derived corrosive fluids through carbonate reservoirs: one-dimensional reactive mass transport modelling (2015)
    Geological Society of London
    Details
    Publication Date: 2015-02-03
    Description: Locally increased porosity of carbonate reservoir rocks may result from acidic fluids that migrated as a pre-oil phase through the reservoir. Here, hydrogeochemical modelling, which is based on the principles of chemical equilibrium thermodynamics, is performed to test such a hypothetical concept. Despite the generic nature of the model, the modelling results give basic and quantitative insights into the mechanisms of calcite dissolution in carbonate reservoirs induced by migrating acidic and corrosive aqueous fluids. The hydrogeochemical batch modelling considers pre-oil-phase aqueous fluids that form by kerogen maturation in siliciclastic source rocks underlying the carbonate reservoir rocks. Although saturated with respect to calcite, migration of such fluids through the carbonate reservoir triggers continuous calcite dissolution along their migration path following a decreasing pressure and temperature regime. One-dimensional reactive transport modelling reveals that thermodynamically controlled chemical re-equilibration among pre-oil-phase fluids, calcite and CO 2(g) is the driving force for continuous calcite dissolution along this migration path. This reflects the increasing solubility of calcite in the system ‘pre-oil-phase fluids/calcite/CO 2(g) ’ with decreasing pressure and temperature. In consequence, such fluids can preserve their calcite-corrosive character, if they are exposed to continuously decreasing pressure and temperature along their migration path through the reservoir. Supplementary material: The modelling input files to ensure retraceability of our modelling approach and its results are available at http://www.geolsoc.org.uk/SUP18802 .
    Print ISSN: 1354-0793
    Topics: Chemistry and Pharmacology , Geosciences
    Published by Geological Society of London
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  • 6
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    Ecological development of Lake Donggi Cona, north-eastern Tibetan Plateau, since the late glacial on basis of organic geochemical proxies and non-pollen palynomorphs (2012)
    ELSEVIER SCIENCE BV
    In:  EPIC3Palaeogeography Palaeoclimatology Palaeoecology, ELSEVIER SCIENCE BV, ISSN: 0031-0182
    Details
    Publication Date: 2014-04-17
    Description: Organic geochemical proxy data from surface sediment samples and a sediment core from Lake Donggi Cona were used to infer environmental changes on the northeastern Tibetan Plateau spanning the last 18.4 kyr. Long-chain n-alkanes dominate the aliphatic hydrocarbon fraction of the sediment extract from most surface sediment samples and the sediment core. Unsaturated mid-chain n-alkanes (nC23:1 and nC25:1) have high abundances in some samples, especially in core samples from the late glacial and early Holocene. TOC contents, organic biomarker and non-pollen-palynomorph concentrations and results from organic petrologic analysis on selected samples suggest three major episodes in the history of Lake Donggi Cona. Before ca. 12.6 cal ka BP samples contain low amounts of organic matter due to cold and arid conditions during the late glacial. After 12.6 cal ka BP, relatively high contents of TOC and concentrations of Botryococcus fossils, as well as enhanced concentrations of mid-chain n-alkanes and n-alkenes suggest a higher primary and macrophyte productivity than at present. This is supported by high contents of palynomorphs derived from higher plants and algae and was possibly triggered by a decrease of salinity and amelioration of climate during the early Holocene. Since 6.8 cal ka BP Lake Donggi Cona has been an oligotrophic freshwater lake. Proxy data suggest that variations in insolation drive ecological changes in the lake, with increased aquatic productivity during the early Holocene summer insolation maximum. Short-term drops of TOC contents or biomarker concentrations (at 9.9 cal ka BP, after 8.0 and between 3.5 and 1.7 cal ka BP) can possibly be related to relatively cool and dry episodes reported from other sites on the north-eastern Tibetan Plateau, which are hypothesized to occur in phase with Northern Hemisphere cooling events.
    Repository Name: EPIC Alfred Wegener Institut
    Type: Article , isiRev
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