Stable Isotope Event Markers Near the Permo-Triassic Boundary in the Karavanke Mountains (Slovenia)

Stable isotope analyses of carbonates and organic matter from the Permo-Triassic boundary section in the Karavanke Mountains, Slovenia, indicate a further example of the “light carbon” event across the boundary. In this section the changes in carbon isotope values were a direct result of the culmination of the marine regression and associated events at the end of the Permian, which caused a drop in primary productivity, as well as related local environmental changes, with no evidence of any considerable diagenetic overprint

Protest event data for Croatia, Portugal, Serbia and Spain: Focus on strike data

‘Disobedient Democracy: A Comparative Analysis of Contentious Politics in the European Semi-periphery’ is a research project implemented by the Faculty of Political Science of the University of Zagreb, in the period 2016-2021, led by Principal Investigator Danijela Dolenec and funded by the Swiss National Science Foundation (IZ11Z0_166540 – PROMYS). The overall objective of the project is to explore how protest politics advances democracy by collecting and analyzing data on protest mobilizations in four countries: Portugal, Spain, Croatia and Serbia.‎info:eu-repo/semantics/publishedVersio

Major, Minor and Trace Elements in Surficial Sediments from the Open Adriatic Sea: A Regional Geochemical Study

The concentrations and distributions of major (Al, Ca, Fe, K, Mg), minor (Mn, P, Ti), and trace elements (Ag, As, Ba, Be, Co, Cr, Cu, Ag, La, Ni, Pb, Sc, Sr, Th, U, V, Zn, Zr), in the surficial sea bottom sediments were studied in an attempt to establish their distribution in the Adriatic Sea. Results indicate that major, minor and several trace elements are strongly related to the catchment geology, their distribution being essentially controlled by the type of sediments. However, the majority of trace elements are believed to have been introduced into the Adriatic from the riverine inflows that are also affected by the impact of industrial, mining and urban wastes. Other sources of these elements are located along the coast. The highest concentrations for several trace elements were thus recorded from the coastal ecosystems and from the most polluted Albanian and Italian rivers. The concentrations of trace elements generally decrease with distance from the coast. The regional distribution patterns are influenced by the counter-clockwise system of the Adriatic Sea currents which carry these elements away from the riverine inflows. Correlation analysis indicates that the trace elements are largely associated with the clay minerals, Fe and P contents rather than with the Mn concentrations. Magnesian minerals are suggested as the carrier for some trace elements (As, Co, Cr, Ni, Se and V) only in the southern Adriatic, which reflects their ophiolitic origin in the Albanian hinterland. Organic matter concentrations does not considerably influence the abundance and distribution of trace metals

Recent Sediments of Makirina Cove (Northern Dalmatia, Croatia): Their Origin Viewed Through a Multidisciplinary Approach

Makirina Cove was formed by the Holocene sea-level rise which caused a marine ingression into the depression formed within Albian–Cenomanian dolomites at approximately 4.5 ka B.P. At present, Makirina Cove represents an restricted, stressed, shallow-marine (<2m) ecosystem characterized by varying seawater temperatures (0–35°C) as well as fluctuating salinities (up to 41‰) affected by seasonally enhanced evaporation, continuous freshwater supply through on-shore and submarine springs associated with the coastal karst area and surface run-off episodes. These environmental conditions have been conducive to high primary production of organic matter resulting in the formation of organic-rich deposits which contain up to 5 wt.% of organic carbon. Up to the present times, 3.5 m of sediments have been deposited indicating a relatively high sedimentation rate estimated at 0.75 m/1.0 ka in the northern central part of the Cove. The sediments are being deposited mostly as poorly sorted clayey–sandy silts. The distribution and concentration of most of the chemical elements is dependant on the mineralogical composition and granulometric features of the Makirina sediments, which show values more or less similar to those from the Central Adriatic. Accordingly, there is a positive correlation with Al and K concentrations increasing off-shore and with the depth being associated with increasing concentrations of clay minerals within the clay fraction. The same holds true for concentrations of some trace elements, especially Mo and Se which is consistent with the distribution pattern of sulphides. Selenium is preferentially enriched in authigenic pyrite and it is probably the major source of Se in the Makirina Cove sediments. The concentrations of Ca, Mg and Sr decrease off-shore and they are linked to the composition of the surrounding carbonate rocks. The saturation indices show that the water is supersaturated with respect to carbonates enabling the precipitation of authigenic amorphous or crystalline carbonate phases from the pore water in the upper segment of the sediment column. According to the oxygen isotopic (δ18O) composition, molluscs precipitated their carbonate shells mostly during warmer periods (May to November) at or near isotopic equilibrium with their ambient waters. The carbon isotopic δ13C composition of mollusc carbonate shells is environmentally affected due to oxidation and decomposition of organic matter as well as influxes of fresh water into the Cove, indicating their formation out of the predicted isotopic equilibrium with atmospheric CO2. Palynological and organic carbon isotopic (δ13C) composition shows that the sedimentary organic matter (SOM) is 70–90% lipid- and hydrogen-rich and on average 2/3 marine derived (mainly phytoplankton, bacteria and marine macrophytes) and 1/3 terrestrially derived (mainly woody tissue). The variations in composition of SOM have been noted as a function of the distance from the shore. The type and the preservation state of SOM and pyrite as well as the measurements of Eh, pH, total alkalinity, dissolved inorganic carbon (DIC) and the enrichment of redox-sensitive trace elements, indicate oxygen-depleted depositional conditions and that the sediment is highly reductive even in the uppermost segment at the sediment/water interface. According to the results obtained from the applied methods, the features of Makirina sediments strongly reflect the given depositional conditions within this restricted, stressed, shallow-marine environment where these organic-rich sediments originate, and may therefore serve as a calibration standard in further investigations

Lead-zinc mining and home-grown foodstuffs (Eastern FYR Macedonia)

Comunicação oral da qual só está disponível o resumo.Mining accompany our civilization since evolution. Since the “Copper (Chalcolithic) Age” and later “Golden Age”, mining activities have created great wealth. Unfortunately, beside wealth the exploitation of metal rich ores, have been almost always correlated with a negative impact to the nearby ecosystems. In this study a broad area around the active Pb-Zn Sasa mine (NE FYR Macedonia) was characterized, to evaluate the contents of some Potentially Toxic Elements (PTE). The PTE were determined in the surrounding fresh waters (lake and rivers), soils and the home-grown vegetables. The evaluation of the potential hazardous ef ects of the PTE, especially on humans, is a key goal. The PTE’s were determined by ICP-AES and ICP-MS. Furthermore also detailed questionnaires were applied among the local inhabitants. Sequential extraction analyses of selected soil samples revealed that the majority of PTE was bounded to water soluble and exchangeable fraction, which shows that those elements (Ag, As, Cd, Cu, Mo, Ni, Pb, Sb and Zn) are therefore very easily mobile and consequently available to plants. According to the applied questionnaires, the consumption of home-grown foodstuf s is high, and certain vegetables, such as tomatoes, peppers, salads, etc., are consumed every day or even more than once a day. Chemical evaluation of PTE in home-grown vegetables revealed that the most crucial PTE’s (those which heavily exceed upper allowable limits) are Cd, Co, Cu, Pb and Zn, and are closely followed by Cr and As. The calculated Health Risk Index (HRI) shows extremely high estimated values, both for adults and children. As the study area is surrounded by rich metallogenic ore deposits, is expected that the natural background is slightly higher than elsewhere. Nevertheless, the concentrations of PTE’s in waters used for irrigation which were increased and the wind-blown (aeorogenic) PTE’s pollution from the nearby tailings dam, both increases the PTE contents in the studied foodstuf s. Thus, the health of inhabitants in this area is of high concern

Radiological and physico-chemical characterization of red mud as an Al-containing precursor in inorganic binders for the building industry

The potential re-use of red mud in the building and construction industry has been the subject of research of many scientists. The presented research is a contribution to the potential solution of this environmental issue through the synthesis of potential construction materials based on red mud. A promising way of recycling these secondary raw materials is the synthesis of alkali-activated binders or alkali activated materials. Alkali-activated materials or inorganic binders based on red mud are a new class of materials obtained by activation of inorganic precursors mainly constituted by silica, alumina and low content of calcium oxide. Since red mud contains radioactive elements like 226Ra and 232Th, this may be a problem for its further utilization. The content of naturally occurring radionuclides in manufactured material products with potential application in the building and construction industry is important from the standpoint of radiation protection. Gamma radiation of the primordial radionuclides, 40K and members of the uranium and thorium series, increases the external gamma dose rate. However, more and more precedence is being given to limiting the radiological dose originating from building materials on the population these days. The aim of this research was to investigate the possible influence of alkali activation-polymerization processes on the natural radioactivity of alkali activated materials synthesized by red mud (BOKSIT a. d. Milići, Zvornik, Bosnia and Herzegovina) and their structural properties. This research confirmed that during the polymerization process the natural radioactivity was reduced, and that the process of alkali activation of raw materials has an influence on natural radioactivity of synthesized materials

Preparation and Characterization of Electrospun PCL/Silk Fibroin Scaffolds

Natural polymer-based scaffolds are generally considered as favourable matrices for the adhesion and growth of cells in tissue repair. One of the most popular materials in this respect is silk fibroin, known for its wide usage in biomedical applications. This work focuses on the development of electrospun scaffolds based on poly(ε-caprolactone) (PCL) and silk fibroin (SF) evaluated regarding the SF effect on their morphology, surface wetting ability, thermal properties, and HaCaT model cell line biocompatibility. The study revealed that the lowest PCL/SF concentration resulted in highest bead-like morphology formation, relatively thick fibers with the presence of random beads in the case of PCL, while uniform and thinner fibers in the case of increasing PCL/SF content scaffolds. The addition of SF reduced the degree of crystallinity in the PCL due to the less organized crystal structure, and decreased its thermal stability. Both SEM and MTT analyses showed cell presence on all scaffolds three days after cell seeding. Although SF improved PCL hydrophilicity, as shown quantitatively by the MTT assay for improved cytocompatibility properties, more structured electrospun PCL/SF scaffold strategies are required. This work is licensed under a Creative Commons Attribution 4.0 International License