Mercury speciation in tailings of the Idrija mercury mine

Five hundred years of mercury (Hg) mining activity in Idrija, Slovenia caused widespread Hg contamination. Besides Hg emissions from the ore smelter, tailings have been found to be the major source of river sediment contamination. In the present study, solid phase binding forms and the aqueous mobility of Hg have been investigated in tailings of the Idrija Hg mine by means of a pyrolysis technique and aqueous Hg speciation. Results show that Hg binding forms differ with the age of the tailings due to the processing of different ores with different roasting techniques. In older tailings, the predominant Hg species is cinnabar (HgS), due to incomplete roasting, whereas in tailings of the 20th century the amount of cinnabar in the material decreased due to a higher efficiency of the roasting process and the increasing use of ores bearing native Hg. In younger tailings, metallic Hg (Hg⁰) sorbed to mineral matrix components such as dolomite and Fe-oxyhydroxides became the predominant Hg binding form in addition to unbound Hg⁰ and traces of HgO. Leaching tests show that in younger tailings high amounts of soluble Hg exist in reactive form. In older tailings most of the soluble Hg occurs bound to soluble complexes. It might be assumed that in the long term, matrix-bound Hg⁰ could be bound to humic acids derived from soils covering the tailings. This means that, despite the lower total Hg concentrations found in the younger tailings, the long-term risk potential of its mobile matrix-bound Hg⁰ is higher than that of older tailings bearing mostly immobile cinnabar.     

A comparison of biological trends from four marine ecosystems: Synchronies, differences, and commonalities

Major features of four marine ecosystems were analyzed based on a broad range of fisheries-associated datasets and a suite of oceanographic surveys. The ecosystems analyzed included the Gulf of Maine/Georges Bank in the Northwest Atlantic Ocean, the Norwegian/Barents Seas in the Northeast Atlantic Ocean, and the eastern Bering Sea and the Gulf of Alaska in the Northeast Pacific Ocean. We examined survey trends in major fish abundances, total system fish biomass, and zooplankton biomasses. We standardized each time series and examined trends and anomalies over time, using both time series and cross-correlational statistical methods. We compared dynamics of functionally analogous species from each of these four ecosystems. Major commonalities among ecosystems included a relatively stable amount of total fish biomass and the importance of large calanoid copepods, small pelagic fishes and gadids. Some of the changes in these components were synchronous across ecosystems. Major differences between ecosystems included gradients in the magnitude of total fish biomass, commercial fish biomass, and the timing of major detected events. This work demonstrates the value of comparative analysis across a wide range of marine ecosystems, suggestive of very few but none-the-less detectable common features across all northern hemisphere ocean systems.     

Tectonometamorphic evolution of the Koralm Complex (Eastern Alps): constraints from microstructures and textures of the ‘Plattengneis’ shear zone

Lattice preferred orientations (LPO) of quartz have been investigated along a south–north oriented section across the Plattengneis of the Koralm Complex (Eastern Alps). The Plattengneis forms an important shear zone within the Austroalpine nappe complex of the Eastern Alps, which has developed during the Cretaceous evolution of the Alpine orogen. The quartz c-axes form small circle distributions in the southernmost parts of the Koralm Complex, which represent the uppermost structural level of the Plattengneis. Further to the North two maxima between the Y and Z directions of the finite strain can be interpreted in terms of preferred slip on the rhomb planes. These fabrics continuously grade into (type I and type II crossed) girdle distributions in a northward direction. A strong maximum near the Y-axis with the tendency to be distributed along a single girdle, with three corresponding maxima of a-axes near the margin of the pole figure, can be observed in the central and northern parts. Such LPO are characteristic for both high grade metamorphic conditions and high finite strain. The microstructures display that the deformation within the Plattengneis shear zone was synmetamorphic. A continuous increase of peak temperatures (and pressure) from approximately 550 °C to approximately 750 °C from the South to the central parts can be inferred from geothermometric calculations. The temperatures then decrease to approximately 650 °C from the central parts to the North. The related pressures increase from 8 to 16 kbar, and then decrease to 10 kbar. The LPO changes that have been observed in the study area are best interpreted in terms of temperature dependence of the activation of glide systems within quartz aggregates. The temperature and pressure evolution may indicate that the central parts of the Koralm Complex have been exhumed by larger amounts than the northern and southern parts. This is also documented by the LPO evolution. Therefore, we assume that the Plattengneis shear zone formed during the exhumation of the Koralm Complex, and is related to the exhumation of high-pressure units in the footwall of this shear zone. Accordingly, the kinematics of the Plattengneis shear zone is rather extensional than thrust-related. The implications for the structural evolution of the Eastern Alps are shortly discussed.     

Influence of low ozone episodes on erythemal UV-B radiation in Austria

This study investigates the influence of low ozone episodes on UV-B radiation in Austria during the period 1999 to 2015. To this aim observations of total column ozone (TCO) in the Greater Alpine Region (Arosa, Switzerland; Hohenpeissenberg, Germany; Hradec Kralove, Czech Republic; Sonnblick, Austria), and erythemal UV-B radiation, available from 12 sites of the Austrian UV-B monitoring network, are analyzed. As previous definitions for low ozone episodes are not particularly suited to investigate effects on UV radiation, a novel threshold approach—considering anomalies—is developed to provide a joint framework for the analysis of extremes. TCO and UV extremes are negatively correlated, although modulating effects of sunshine duration impact the robustness of the statistical relationship. Therefore, information on relative sunshine duration (SD_rel), available at (or nearby) UV-B monitoring sites, is included as explanatory variable in the analysis. The joint analysis of anomalies of both UV index (UVI) and total ozone (∆UVI, ∆TCO) and SD_rel across sites shows that more than 65% of observations with strongly negative ozone anomalies (∆TCO < −1) led to positive UVI anomalies. Considering only days with strongly positive UVI anomaly (∆UVI > 1), we find (across all sites) that about 90% correspond to negative ∆TCO. The remaining 10% of days occurred during fair weather conditions (SD_rel ≥ 80%) explaining the appearance of ∆UVI > 1 despite positive TCO anomalies. Further, we introduce an anomaly amplification factor (AAF), which quantifies the expected change of the ∆UVI for a given change in ∆TCO.

     

Of solar collectors,wind power,and car sharing: Comparing and understanding successful cases of grassroots innovations

Grassroots activities so far have not been sufficiently appreciated as sources of innovation. Transition processes towards more sustainable socio-technical energy, transport or production systems, however, are hardly imaginable without a broader participation of engaged citizens. This paper presents and compares three cases of successful grassroots innovations for sustainability. In particular we compare the development of wind technology in Denmark, the solar collector do-it-yourself movement in Austria, and the development of car sharing in Switzerland. The paper aims at a better understanding of the preconditions, patterns of growth and change and factors of success of grassroots innovations for more sustainable socio-technical regimes such as energy and transport. In the analysis we focus on dimensions such as the structural conditions and resources of origin, motivations of social actors involved, learning processes and outcomes, competences and activities of those actors, processes of institution-building, and the relationships to mainstream market actors. Based on the empirical background the paper discusses implications for the theorisation of grassroots innovations for greater sustainability and draws implications for further research.     

Die rezente hydrothermal-sedimentäre Lagerstätte Atlantis-II-Tief im Roten Meer

Zusammenfassung Die in Entstehung befindliche hydrothermal-sedimentäre Lagerstätte Atlantis-II-Tief im Roten Meer wurde in den Jahren 1969, 1971 und 1972 von den Forschungsschiffen Wando River und Valdivia aus genauer untersucht. Die Detailkartierung zeigt eine Fallenstruktur, die hauptsächlich durch NW-streichende Grabenrandverwerfungen hervorgerufen wurde. Die in die se Depression in ihren tiefsten Teil einströmenden metallhaltigen Solen hielten das für die Lagerstättenbildung, besonders das für die Sulfidausfällung nötige Milieu über längere Zeit aufrecht. Diese seit dem ausgehenden Pleistozän anhaltende stabile Situation wurde einige Male von Lava-Ausflüssen, tektonischen Ereignissen und Verlagerung der Quellen unterbrochen. Diese Vorgänge und die komplizierte Morphologie der solegefüllten Becken führten zu einer sehr komplexen Faziesentwicklung und stratigraphischen Abfolge. Insgesamt läßt sich, von den Quellen ausgehend, eine Zonierung von sulfidisch-silikatischer zu manganitischlimonitischer Ausfällung beobachten.

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The Atlantis II Deep, a hydrothermal-sedimentary metal depositin statu nascendi has been investigated in detail 1969, 1971 and 1972 with the research vessels Wando River and Valdivia. The new bathymetric map reveals a trap structure mainly caused by NW-striking faults, limiting local grabens. The metalliferous brines discharging into the deepest part of this depression maintained the conditions necessary for the formation of the deposit, esp. of the sulfides, for a long time.This stabil situation active since the end of the Pleistocene was several times disturbed by lava flows, tectonic events and displacement of the discharge vents.These events and the complicate morphologic structure of the brine-filled deep are responsible for a very complex development of lithologic facies and the stratigraphic sequence. There is a general deposit differentiation from sulfidic-silicatic precipitation near the discharge points and formation of limonite and manganite outside the brines.

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Résumé Pendant les années 1969, 1971 et 1972 les gisements hydrothermaux sédimentaires Atlantis II, en voie de formation dans la Mer Rouge, ont fait l'objet de campagnes scientifiques détaillées entreprises par les navires océanographiques Wando River et Valdivia.La carte morphologique montre une structure de descente qui a été formée principalement par des failles de direction NW délimitant des graben. Les saumures métallifères affluant dans la partie la plus profonde de cette dépression ont maintenu pendant une certaine durée le milieu nécessaire à la formation du gisement, et surtout à la précipitation des sulfures. Cette situation restée stable depuis la fin du Pléistocène a été interrompue plusieurs fois des émissions basaltiques, par des dislocations tectoniques et par le déplacement des sources. Ces événements, ainsi que la morphologie compliquée du bassin rempli de saumures, ont conduit à un développement très complexe des faciès lithologiques et de la séquence stratigraphique. Dans l'ensemble on peut constater une zonation des faciès avec précipitations sulfurosilicatées près des points d'entrée des saumures et manganolimonitiques plus à l'écart.

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Distribution and speciation of mercury in soil in the area of an ancient mercury ore roasting site,Frbejžene trate (Idrija area,Slovenia)

In the initial period of mining activities in the Idrija basin (the16^th and the first half of the17^th centuries), Hg ore processing was performed at various small-scale roasting sites in the woods surrounding Idrija, by roasting ore in earthen vessels. The recovery rate of this method was very low; about half of Hg was lost, causing soil contamination and considerable amounts of waste material that could potentially leach Hg into the surrounding environment. The main aims of present geochemical study were to determine the contents, vertical distribution and speciation of Hg in soils at the roasting site at Frbej?ene trate in order to verify the extreme pollution of ancient Hg ore roasting sites in the Idrija area and to establish their significance in the wider spatial contamination of soils and aquatic systems. Soil sampling was performed at the area of the former roasting site. The organic matter-rich surface soil layer (SOM) and underlying mineral soil were sampled at 63 sampling locations. Mercury speciation was performed using Hg thermo-desorption-AAS to distinguish cinnabar from potentially bioavailable forms. The results indicate extremely high Hg concentrations with a maximum of 37,000 mg/kg in SOM and 19,900 mg/kg in mineral soil. The established Hg median in soil was 370 mg/kg and in SOM 96.3 mg/kg. Spatial distributions of Hg in SOM and soil showed very high Hg contents in the central area and decreased rapidly with distance. The results of Hg thermo-desorption measurements indicated the presence of cinnabar (HgS) and Hg bound to organic or mineral soil matter. A significant portion (35–40%) of Hg in the investigated soil and SOM samples was comprised of non-cinnabar compounds, which are potentially bioavailable. It has been shown that soils contain high amounts of potentially transformable non-cinnabar Hg, which is available for surface leaching and runoff into the surrounding environment. Therefore, contaminated soils and roasted residues at the studied area are important for persistent Hg release into the aquatic ecosystem.