Assessment of heavy metal contamination levels of street dust in the city of Lublin,E Poland     

Wojciech Zgłobicki  Małgorzata Telecka  Sebastian Skupiński  Aneta Pasierbińska  Marcin Kozieł 《Environmental Earth Sciences》2018,77(23):774

Heavy metals are constantly emitted into the environment and pose a major threat to human health, particularly in urban areas. The threat is linked to the presence of Cd, Cr, Cu, Ni, Pb, and Zn in street dust, which consists of mineral and organic particles originating from the soil, industrial emitters, motor vehicles, and fuel consumption. The study objective was to determine the level of street dust contamination with trace metals in Lublin and to indicate their potential sources of origin. The analyses were carried out with an energy-dispersive X-ray fluorescence spectrometer. The sampling sites (49) were located within the city streets characterised by varying intensity of motor traffic. The following mean content values and their variation (SD) were determined: Cd: 5.1?±?1.7 mg kg^?1, Cr: 86.4?±?23.3 mg kg^?1, Cu: 81.6?±?69.2 mg kg^?1, Ni: 16.5?±?3.9 mg kg^?1, Pb: 44.1?±?16.4 mg kg^?1, and Zn: 241.1?±?94.6 mg kg^?1. The level of pollution was assessed with several widely used geochemical indices (geoaccumulation index, enrichment factor, pollution index, index of ecological risk, and potential ecological risk index). For most of the indices, the mean (median) values are arranged in the following manner: Zn?>?Cu(or Cd)?>?Pb?>?Ni?>?Cr. In general, street dust in Lublin does not show pollution with Cr, Ni, and Pb. I_geo and EF indices show moderate levels for Cu, Cd, and Zn; their presence in street dust is linked with anthropogenic factors (motor traffic). A significant threat is posed by Cd, and more than half of the samples show considerable pollution with cadmium (median for the index of ecological risk: 151). The spatial pattern of indices and the results of statistical analyses (CA, PCA) indicate three groups of elements: (1) Cr and Ni: natural origin; (2) Pb: mixed origin; and (3) Cd, Cu, and Zn: anthropogenic origin (mainly motor vehicle traffic). Higher content values for metals of anthropogenic origin in street dust indicate that it is a source of pollution of soil and air in the city.  相似文献   

Fluid–Rock Interactions in Geothermal Reservoirs,Germany: Thermal Autoclave Experiments Using Sandstones and Natural Hydrothermal Brines     

Schäffer  Rafael  Götz  Emilia  Schlatter  Nils  Schubert  Gabriela  Weinert  Sebastian  Schmidt  Stefanie  Kolb  Ute  Sass  Ingo 《Aquatic Geochemistry》2022,28(2):63-110

As renewable energy, geothermal can contribute substantially to the energy transition. To generate electricity or to harvest heat, high-saline fluids are tapped by wells of a few kilometres and extracted from hydrothermal reservoirs. After the heat exchanger units have been passed by, these fluids are reinjected into the reservoir. Due to the pressure and temperature differences between the subsurface and the surface, as well as the cooling of the fluids in the power plant, unwanted chemical reactions can occur within the reservoir, in the borehole, and within the power plant itself. This can reduce the permeability of the reservoir as well as the output of the geothermal power plant. This study aims to simulate real subsurface reactions using batch and leaching experiments with sandstone or sandstone powder as solid phase, and deionised water or natural brine as liquid phase. It is demonstrated that fluid composition changes after only a few days. In particular, calcite, aragonite, clay minerals, and zinc phases precipitate from the natural brine. In contrast, in particular minerals containing potassium, arsenic, barium, and silica are dissolved. Due to the experimental set-up, these mineral reactions mainly took place on the surface of the samples, which is why no substantial changes in petrophysical properties could be observed. However, it is assumed that the observed reactions on the reservoir scale have a relevant influence on parameters such as permeability.

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Geology,permafrost, and lake level changes as factors initiating landslides on Olkhon Island (Lake Baikal,Siberia)     

Sebastian Tyszkowski  Halina Kaczmarek  Michał Słowiński  Elena Kozyreva  Dariusz Brykała  Artiom Rybchenko  Viktoria A. Babicheva 《Landslides》2015,12(3):573-583

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Signature of explosive volcanic eruptions in the sediments of a high-altitude Swiss lake     

Alex Blass  Martin Grosjean  David M. Livingstone  Michael Sturm 《Journal of Paleolimnology》2008,39(1):35-42

The analysis of 125 years of well-dated varved sediments in Lake Silvaplana, located at 1,791 m a.s.l. in the Upper Engadine region of south-eastern Switzerland, reveals that 7 out of the 8 climatically relevant explosive volcanic eruptions between A.D. 1880 and 2004 were followed by distinct peaks in median grain-size. Although the underlying mechanisms are yet unclear, an analysis of local meteorological data suggests that this phenomenon is unlikely to be related to any change in air temperature associated with the eruptions, but instead may be related to an increase in autumn precipitation subsequent to the eruptions that led to the erosion and fluvial transport of particles larger than normal.  相似文献   

Carbonate drifts as marine archives of aeolian dust (Santaren Channel,Bahamas)     

Sebastian Lindhorst  Christian Betzler  Marco Wunsch  Thomas Lüdmann  Gerhard Kuhn 《Sedimentology》2019,66(4):1386-1409

Sediment data from the Bahamian Santaren carbonate drift reveal the variability of trans‐Atlantic Saharan dust transport back to about 100 ka bp (Marine Isotope Stage 5·3) and demonstrate that carbonate drifts are a valuable pelagic archive of aeolian dust flux. Carbonate drift bodies are common around tropical carbonate platforms; they represent large‐scale accumulations of ocean‐current transported material, which originates from the adjacent shallow‐water carbonate factory as well as from pelagic production, i.e. periplatform ooze. Subordinately, there is a clay‐size to silt‐size non‐carbonate fraction, which typically amounts to less than 10% of the sediment volume and originates from aeolian and fluvial input. Sedimentation rates in the 5·42 m long core GeoHH‐M95‐524 recovered 25 km west of Great Bahama Bank in the Santaren Channel ranges from 1·5 to 24·5 cm ka^?1 with lowest values during the last glacial lowstand and highest values following platform re‐flooding around 8 ka bp . These sedimentation rates imply that carbonate drifts have not only the potential to resolve long‐term environmental changes on orbital timescales, but also millennial to centennial fluctuations during interglacials. The sediment core has been investigated with the aim of characterizing the lithogenic dust fraction. Laboratory analyses included X‐ray fluorescence core scanning, determination of carbonate content and grain‐size analyses (of bulk and terrigenous fraction), as well as visual inspections of the lithogenic residue; the age model is based on oxygen isotopes and radiocarbon ages. Data show that the input of aeolian dust in the periplatform ooze as indicated by Ti/Al and Fe/Al element ratios abruptly increases at 57 ka bp , stays elevated during glacial times, and reaches a Holocene minimum around 6·5 ka bp , contemporary to the African Humid Period. Subsequently, there is a gradual increase in dust flux which almost reaches glacial levels during the last centuries. Grain‐size data show that the majority of dust particles fall into the fine silt range (below 10 μm); however, there is a pronounced coarse dust fraction in the size range up to 63 μm and individual ‘giant’ dust particles are up to 515 μm in size. Total dust flux and the relative amounts of fine and coarse dust are decoupled. The time‐variable composition of the grain‐size spectrum is interpreted to reflect different dust transport mechanisms: fine dust particles are delivered by the trade winds and the geostrophic winds of the Saharan Air Layer, whereas coarse dust particles travel with convective storm systems. This mode of transport ensures continuous re‐suspension of large particles and results in a prolonged transport. In this context, grain‐size data from the terrigenous fraction of carbonate drifts provide a measure for past coarse dust transport, and consequently for the frequency of convective storm systems over the dust source areas and the tropical Atlantic.  相似文献   

Lack of association between color morphs of the Jellyfish Cassiopea andromeda and zooxanthella clade     

Kathrin P. Lampert  Patrick Bürger  Sebastian Striewski  Ralph Tollrian 《Marine Ecology》2012,33(3):364-369

Understanding the ecology and evolution of the cnidarian-algal symbiosis is of major scientific interest as it is sensitive to temperature and strong light and may therefore be susceptible to climate change. The stability of this mutualism is often mediated by host color pigments that influence photosynthetic activity in symbiotic dinoflagellates either by providing the photosystem with irradiance of suitable wavelength or by protecting it from much too much and potentially damaging light. Like scleractinian corals, the upside-down jellyfish, Cassiopea andromeda, relies heavily on the nutrients provided by its symbionts of the dinoflagellate genus Symbiodinium. It occurs in several conspicuously different color morphs and is found in habitats with high levels of irradiation. We tested whether the color morphs of Cassiopea were correlated with the Symbiodinium distribution in the host and whether host color was associated with different clades of Symbiodinium. We found that the presence of color pigment did not correlate with the distribution of Symbiodinium in the host. Symbiodinium was found in both the colored tentacles of the jellyfish and the colorless feeding tentacles. At least six different color morphs co-occurred in the very shallow waters of the Red Sea, but they all hosted a single Symbiodinium clade (clade A1). Therefore, no correlation of host color morph and Symbiodinium clade could be found. Photoaccumulative or photoprotective functions of host pigments, as proposed for some scleractinian corals, thus seem unlikely in the colored tentacles (vesicles) of the upside-down jellyfish Cassiopea andromeda.  相似文献   

Active galaxies in the mid-infrared     

E. Sturm  D. Lutz  R. Genzel  T. Alexander  A. Sternberg  H. Netzer  A.F.M. Moorwood 《Astrophysics and Space Science》1999,266(1-2):169-174

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A Recent Shellfish Toxin Investigation in China   总被引：30，自引：0，他引：30  

Mingjiang Zhou  Jun Li  Bernd Luckas  Rencheng Yu  Tian Yan  Christian Hummert  Sebastian Kastrup 《Marine pollution bulletin》1999,39(1-12):331-334

A shellfish toxin investigation along the Chinese coast has recently been conducted using both HPLC and mouse assay methods. The results showed that DSP was widely distributed in different shellfish species in China. 26 out of 89 samples had DTX1 (dinophysistoxin-1) or OA (okadaic acid) but the DSP content in most shellfish samples did not reach the regulatory limit for human consumption adopted in many countries (20 μg/100 g soft tissue). PSP was also found in 5 out of 96 samples along the coast. One sample, Chlamys nobilis from Hong Kong contained high levels of PSP (320 μg STX equivalent/100 g soft tissue), compared to the regulatory limit (80 μg STX equivalent/100 g soft tissue). After the recent outbreak of red tide in Hong Kong waters, three further shellfish samples were collected within 40 days to investigate the impacts of this event. It was shown that high levels of PSP continued to exist in Hong Kong waters. This report provides the first report of DSP and PSP distribution along the Chinese coast.  相似文献   

Nordic Landscapes: Region and Belonging on the Northern Edge of Europe – Edited by Michael Jones and Kenneth R Olwig
The Nordic Model: Scandinavia since 1945 – By Mary Hilson     

Sebastian  Eiter 《The Geographical journal》2009,175(4):320-321

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The influence of great earthquakes on volcanic eruption rate along the Chilean subduction zone     

Sebastian F.L. Watt  David M. Pyle  Tamsin A. Mather 《Earth and Planetary Science Letters》2009,277(3-4):399-407

Seismic activity has been postulated as a trigger of volcanic eruption on a range of timescales, but demonstrating the occurrence of triggered eruptions on timescales beyond a few days has proven difficult using global datasets. Here, we use the historic earthquake and eruption records of Chile and the Andean southern volcanic zone to investigate eruption rates following large earthquakes. We show a significant increase in eruption rate following earthquakes of M_W > 8, notably in 1906 and 1960, with similar occurrences further back in the record. Eruption rates are enhanced above background levels for ~ 12 months following the 1906 and 1960 earthquakes, with the onset of 3–4 eruptions estimated to have been seismically influenced in each instance. Eruption locations suggest that these effects occur from the near-field to distances of ~ 500 km or more beyond the limits of the earthquake rupture zone. This suggests that both dynamic and static stresses associated with large earthquakes are important in eruption-triggering processes and have the potential to initiate volcanic eruption in arc settings over timescales of several months.  相似文献