EDS analysis of Portland ash cement degradation in an aggressive environment

The behaviour of Portland cement with and without 30% fly ash addition in aggressive solutions was studied. This paper considers the sulphate corrosion of the hardened cement paste. The cement paste test samples were prepared, cured in water for 21 day and then exposed to the influence of aggressive environment (10% (NH₄SO₄ solution). The measurements of several properties were carried out and the results were analyzed.

The image of the surface composition and morphology of the cement paste test samples was made by scanning electron microscopy (SEM). Concentration gradient of sulphate ions in cement paste depth was obtained by energy‐dispersive analysis (EDS).     

Distribution of selected essential (Co, Cu, Fe, Mn, Mo, Se, and Zn) and nonessential (Cd, Pb) trace elements among protein fractions from hepatic cytosol of European chub (Squalius cephalus L.)

Association of selected essential (Co, Cu, Fe, Mn, Mo, Se, and Zn) and nonessential (Cd, Pb) trace elements with cytosolic proteins of different molecular masses was described for the liver of European chub (Squalius cephalus) from weakly contaminated Sutla River in Croatia. The principal aim was to establish basic trace element distributions among protein fractions characteristic for the fish living in the conditions of low metal exposure in the water. The fractionation of chub hepatic cytosols was carried out by size exclusion high performance liquid chromatography (SE-HPLC; Superdex? 200 10/300 GL column), and measurements were performed by high resolution inductively coupled plasma mass spectrometry (HR ICP-MS). Elution profiles of essential elements were mostly characterized by broad peaks covering wide range of molecular masses, as a sign of incorporation of essential elements in various proteins within hepatic cytosol. Exceptions were Cu and Fe, with elution profiles characterized by sharp, narrow peaks indicating their probable association with specific proteins, metallothionein (MT), and ferritin, respectively. The main feature of the elution profile of nonessential metal Cd was also single sharp, narrow peak, coinciding with MT elution time, and indicating almost complete Cd detoxification by MT under the conditions of weak metal exposure in the water (dissolved Cd concentration ≤0.3 μg L^?1). Contrary, nonessential metal Pb was observed to bind to wide spectrum of proteins, mostly of medium molecular masses (30–100 kDa), after exposure to dissolved Pb concentration of ~1 μg L^?1. The obtained information within this study presents the starting point for identification and characterization of specific metal/metalloid-binding proteins in chub hepatic cytosol, which could be further used as markers of metal/metalloid exposure or effect on fish.     

Accumulation of Mn and Pb in linden (Tilia platyphyllos Scop.) bark and wood

As an indicator of environmental pollution, we collected tree rings and bark of linden (Tilia platyphyllos Scop.) from four sampling locations in Serbia. Mn and Pb were determined with a spectrochemical method that has an argon-stabilized U-shaped DC arc with aerosol supply as excitation source. Increased concentrations of Mn in linden tree rings and bark were found at the Debeli Lug location, where the Mn transfer factors were largest. The availability of Mn in soil and tree rings was greatly influenced by pH. Since 1950, Mn level decreased more noticeably on acidic soils. Higher concentrations of Pb were found in linden tree rings and bark at the locations Fru?ka Gora and Zemun. Proximity of the road to Novi Sad at both sites may be a possible reason for this. The Pb transfer factor was highest at Fru?ka Gora. The ratio of bioavailable elements in soil for Mn and Pb were also calculated. Close correlations between Mn and Pb concentrations in linden tree rings and the ratio of bioavailable elements in soil were seen at all four locations.     

Kinetics of heterogeneous ozone reactions

Earlier results on ozone destruction on solid surfaces gave apparent first order kinetics. Estimating the reaction kinetics from our data on ozone destruction on various powders (silica-gel, alumina, wood ash, coal ash, Saharan sand, calcite), we found that only calcite and wood ash exhibited such a behaviour. Removal of ozone by other powders used showed two straight lines in ln c-t plot with two different half-lives, t'(1/2) < t'(1/2). Comparing the kinetic constants for ozone removal on silica-gel and that of ozone reactions with polynuclear aromatic hydrocarbons (PAHs) adsorbed in submonolayer coverage on the same powder, the first reaction seems to be more likely in the case of pyrene and particularly fluoranthene. Enhanced ozone destruction on airborne aerosols could be an additional reason for fluoranthene stability in the real atmosphere.     

The state of bird and nature protection in Croatia

Summary Croatia, as a Mediterranean country in the south-eastern part of Europe, is an area with a characteristic flora and fauna. The ornithofauna of Croatia reflects that it is a breeding area for some of the globally endangered bird species, as well as a site for the spring/autumn passage and the wintering of European migratory birds. Many ornithologically significant localities are designated and there are 20 ornithological reserves and four wetland sites that are on the list of the Ramsar Convention.In Croatia, there are four governmental organizations dealing with scientific research on birds of which the Institute for Ornithology of the Croatian Academy, of Sciences and Arts is that with the longest tradition. There are also many non-governmental organizations dedicated to the protection of environment, but only the Croatian Society for Bird and Nature Protection is dedicated mostly to bird protection. There are not many sources of funding for research and the protection of birds; the chief source being the Ministry of Sciences and Technology of the Republic of Croatia.Croatia has to establish new legislation according to European criteria and The Hunting Law, The Nature Protection Law and The Environment Protection Law have been recently accepted in Parliament. International Conventions, such as Bern, Bonn and Washington, have yet to be adopted. Foreign, hunting tourism, especially organized by fishpond authorities, is believed to be killing large numbers of protected water birds. A red data book exists only for plants and mammals and this makes biological assessments difficult.With the end of military operations and the reintegration of the occupied areas of Croatia, an assessment of the damage to the national parks and nature reserves, and to nature in general, will be necessary. Bird and nature conservation in Croatia remains promising, provided the legal control of the Croatian government over the occupied parts of the country is restored soon and international organizations give assistance.Dr Jasmina Muini is Croatian by birth and she has studied in Paris, Oslo, and Zagred where she gained her PhD. She is a President of the Croatian Society for Bird and Nature Protection, a member of the Croatian Parliament Board for Environmental Protection, vice-president of the Scientific Council of the Zoological Garden in Zagreb, and a member of other Croatian environmental bodies. She is a leading authority on the ornithofauna of the Croatian wetlands.     

The Quality of Water Resources in Dalmatia

The purpose of this study was to monitor and record the specific characteristics and properties of most of the important water resources in Dalmatia located in Southern Croatia for a period of 5 years (1998–2002) according to established standards for drinking water. The paper presents a detailed account of their chemical content, the classification and the concentration of salts. The bacteriological pollution levels are indicated by the total coliform bacterial levels (MPN coli/100 mL). The water characteristics are expressed by coefficients, which represent the ratios between water ingredients. The Ca/Mg eq ratio, SO₄/Cl eq ratio and K₁, K₂ for bicarbonate hardness were calculated. The hygienic characteristics of the water samples were expressed by the total coliform bacteria estimation (MPN coli/100 mL), the permanganate consumption (KMnO₄) and biological oxygen demand (BOD₅). Karst waters in Dalmatia are moderately hard, the SO₄/Cl ratio is 0.38–1.6, non-corrosive (K₁ lower than 0.2) and not significantly mineralised (< 500 mg/L minerals). Sulphate waters are generally hard, the SO₄/Cl ratio is higher than 1.6, K₁ is 0.2–0.65. Marine waters are quite hard or hard, particularly at the river estuaries, the SO₄/Cl ratio is lower than 0.38, and K₁ is higher than 0.65. The groundwater and springs in Dalmatia are less polluted than surface waters. A majority of these have a geometric average value of MPN coli < 150/100 mL of water observed in 24 of 42 locations studied. The highest bacteriological pollution was found in nine locations where MPN coli > 1000/100 mL and moderate pollution was found in nine locations where MPN coli is between 150 and 1000/100 mL of water. The physical and chemical parameters determined for the most sources in Dalmatia are safe below the international permissible limits.     

Mercury and other elements in lichens near the INA Naftaplin gas treatment plant, Molve, Croatia

This paper describes the use of epiphytic lichens as bioindicators for spatial monitoring of mercury and other elements in air near the natural gas treatment facilities at Molve, Croatia. It is well known that at this location the concentration of mercury in natural gas is very high and therefore it has to be removed from natural gas before further processing in order to prevent technological and environmental problems. In order to monitor the efficiency of an industrial facility for removal of mercury from natural gas, mercury measurements in air and lichens were performed during 9 months in 1997/1998. In situ lichens Parmelia sulcata, Xantoria parientina and Hypogymnia physodes and transplanted lichen species Hypogymnia physodes were used. A good correlation between mercury concentrations in air and lichens was found. The concentrations of barium and bromium were also significantly elevated in transplanted lichens, most probably related to technological process at the gas treatment plant and/or other geological factors. It was confirmed that lichens can successfully be used as bioindicators, provided a careful experiment is designed, particularly the amount of lichens transplanted, the duration of exposure and the initial levels and homogeneity of transplanted lichens.     

Evaluating forest management practices using a GIS-based cellular automata modeling approach with multispectral imagery

The objective of this study was to develop an integrated geographic information system (GIS) cellular automata (CA) model for simulating insect-induced tree mortality patterns in order to evaluate the influence of different forest management activities to control insect outbreaks. High-resolution multispectral images were used to determine susceptibility of trees to attack, whereas the GIS-based CA model simulated the effectiveness of clear-cuts and thinning practices for reducing insect-induced tree mortality. The results indicate that thinning susceptible forests should be more effective than clear-cutting for reducing tree loss to insect outbreaks. This study demonstrates the benefits of an integrated approach for understanding and evaluating forest management activities and expresses the need for spatial analysis and modeling for improving forest management practices.     

Arsenic removal from water by chemisorption filters

The concept of multiple separation by chemisorptive filters was applied and investigated in the process of arsenic removal from water. Chemisorption filters were made by the paper manufacturing method and consisted of cellulose, cationic and anionic ion exchangers, activated carbon and a corresponding chemical agent. In this work chemisorption filters were activated with Ag+, Mg2+, Cu2+, Al3+ and Fe3+ ions, and their chemical contribution to total arsenic removal from the water was analyzed. It was concluded that Cu2+ ions exhibited the best removal effect. Using a chromatographic continuous system with multifunctional filters, which combines the effects of adsorption, ion exchange and filtration, a decrease in the arsenic concentration was determined; for an active layer of 8 mm and a contact time of 2 s it was more than 1000-fold. All processes were performed in batch and chromatographic continuous systems under equilibrium or dynamic conditions. The results of the investigations have shown that arsenic removal is valence dependent (the removal of pentavalent arsenic was more effective). The initial concentration, pH and pollutants in anionic forms, which affected the selectivity, were important for all the processes investigated. The mechanisms of pollutant removal were determined on the basis of measurements of active Cu2+ ion propagation inside the filter structure. By correlating the front propagation of active ions and the pollutant output concentration a more exact model for the removal process was obtained.