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This paper describes a characteristic landslide model for landslides typically hosted in Neogene formations in Serbia, especially along the right banks of the Sava and Danube Rivers. It is focussed on the particular landslide Umka near Belgrade, which is a paradigm for numerous landslides in that area. Various field investigations and laboratory tests carried out in several campaigns, including 1979, 1991-1993 and 2005, underpinned the conception of a general model for this typological landslide. Additionally, a new landslide monitoring campaign started in 2010 provided supplementary data support for the model development. Landslide characteristics, sliding mechanism and material properties based on all these data are first summarised and discussed and then featured in a general model. It is assumed that the landslide is hosted in the weathered zone of grey marls and that the main sliding surface typically propagates along the contact between the fresh and weathered marls. Furthermore, the triggering is principally associated with lateral river erosion in the landslide toe, although heavy precipitation and snow melting have been witnessed to be important indirect triggers. Their correlation to the recorded displacements was difficult to determine due to complex hydrogeological relations and an isolated groundwater system, which is another common characteristic of this landslide type. Back analysis on the basis of the adopted model and the determined geotechnical parameters has been performed. The latter analysis is of particular interest because the Umka landslide is currently under consideration for a mitigation and stabilisation plan related to the construction of a new motorway route. [ABSTRACT FROM AUTHOR]

Global warming affects the hydrological cycle and the long-term water budget of river basins. Flow variations have been noticed in the Danube River Basin, especially in its south-western parts where a downward trend in mean annual flows has been prevalent in the past several decades. Time series of mean annual and seasonal flows of the Sava River at hydrological stations Sremska Mitrovica and Zagreb are analysed in this paper. The trend is assessed with the Mann-Kendall test including the effect of serial correlation. Additionally, the trends are assessed in the multi-temporal framework. It is concluded that the long-term periodicity of annual flows has a considerable impact on the time series trend. Long-term component with cycles of 40 years in mean annual flows are detected by the time series analysis in frequency domain. Regression analysis showed a significant correlation between mean annual flows of the Sava River and annual precipitation, mean annual atmospheric pressure and air temperatures at meteorological station Ljubljana, as well as with the North Atlantic Oscillation (NAO) Index. [ABSTRACT FROM AUTHOR]

Purpose: Riparian zone contamination is a growing problem for several European catchments due to high anthropogenic pressures. This study investigates As, Cd, Cr, Cu, Ni, Pb, and Zn concentrations in the Sava River riparian zone, characterized by wide agricultural areas, various geological substrates, and different types of industrial pollution. The accumulation and mobility of these elements were studied because they are listed as priority substances in the Water Framework Directive and environmental objectives for surface waters.Materials and methods: Sampling was performed during the sampling campaign of the EU 7th FW-funded GLOBAQUA project in September 2015 during a low-water event. Soil samples were collected along the Sava River at 12 selected sampling sites, from a depth of 0-30 cm, at a distance of 10-15 m from the river bank. The extent of pollution was estimated by determining total and readily soluble element concentrations in the soils. Potential ecological risk and the source of the selected elements in the soils was determined using the enrichment factor (EF), potential ecological risk index (RI), and statistical methods such as the principal component analysis (PCA) and multiple linear regression analysis (MLRA).Results and discussion: This study showed that concentrations of the selected elements increase along the Sava. In terms of origin, PCA and MLRA indicated that Cr and Ni in soils are predominantly lithogenic, while As, Cd, Pb, and Zn are both lithogenic and anthropogenic (ore deposits, industry, and agriculture). PCA singled out Cu since its origin in soil is most probably from specific point-source pollution. EF was generally minor to moderate for most of the examined elements, apart from Cu, for which the EF was significant at one sampling site. Overall ecological risk (RI) fell within the low-risk category for most sites, apart from Belgrade sampling site (BEO), where high total Cd content affected individual and overall ecological risk indicators, indicating Cd could represent a considerable ecological risk for the downstream riparian zone.Conclusions: At downstream sites, there was a noticeable increase in PTE content, with Cd, Cr, Ni, and Zn exceeding the proposed threshold values for European soils, indicating rising contamination in riparian soils. In terms of the ecological risk, only Cd could pose a potential ecological threat for the downstream riparian zone. [ABSTRACT FROM AUTHOR]

Purpose: The first comprehensive evaluation and trend analysis of long-term nitrogen (N) and phosphorus (P) data was performed for the Sava River Basin (SRB) at locations in Slovenia, Croatia, and Serbia. Materials and methods: Data on long-term water quality at eight selected locations were evaluated statistically based on the period of reporting, availability of flow data, and the experience from our previous investigations. Trends in NO and PO concentrations at locations were identified using simple linear regressions on log-transformed data. Results and discussion: Analysis indicated spatial and seasonal variability between locations. The highest long-term annual mean NO and PO concentrations were observed in Croatia and Serbia at locations that are susceptible to anthropogenic nutrient loading arising from high human population densities and intensive agricultural land use. Temporal variations indicate that river flow plays an important role in the distribution of NO and PO concentrations. Low flow during the summer months promotes reductive conditions leading to a minimum in annual mean NO concentrations and a maximum in annual mean PO concentrations resulting from the release of inorganic P from sediments. The highest annual mean NO concentrations were observed in winter/autumn under higher flow conditions that leach NO from soil and banks into the river. The results of trend analysis show a reduction of nutrients at the majority of locations ranging from 8 to 58 %. Conclusions: Although trends in NO and PO concentrations indicate a decrease at the majority of selected locations, it is still necessary to apply appropriate removal technologies in order to reduce the nutrient loads into the Sava River Basin and thereby improve water quality. [ABSTRACT FROM AUTHOR]

Nikola Tesla B power plant (TENT B), located at the Sava River, in Obrenovac, 50 km west from the Serbian's capital, Belgrade, is the second largest coal-fired power plant in the country, consisting of two blocks, each of 620 MW capacity. In order to investigate the threat polycyclic aromatic hydrocarbons (PAHs) from deposited coal ash, obtained by coal combustion in this power plant, can represent for the surrounding environment, samples of coal ash were submitted to extraction with river water used for transport of coal ash to the dump, as well as with water of different ionic strength and acidity. It was found that, out of 16 EPA priority PAHs, only naphthalene, acenaphthylene, fluorene, phenantrene, fluoranthene, and pyrene were found in measurable concentrations in the different extracts. Their combined concentration was around 0.1 μg/L, so they do not, in terms of leached concentrations, represent serious danger for the surrounding environment. In all cases of established (and leached) PAH compounds, changes of ionic strength, acidity, or the presence of organic compounds in river water may to some extent influence the leached concentrations. However, under the examined conditions, similar to those present in the environment, leached concentrations were not more than 50 % greater than the concentrations leached by distilled water. Therefore, water desorption is likely the most important mechanism responsible for leaching of PAH compounds from filter coal ash. [ABSTRACT FROM AUTHOR]

Region-specific contaminant prioritisation is an important prerequisite for sustainable and cost-effective monitoring due to the high number of different contaminants that may be present. Surface water and sediment samples from the Sava River, Croatia, were collected at four locations covering a 150-km-long river section characterised by well-defined pollution gradients. Analysis of contaminant profiles along the pollution gradients was performed by combining toxicity screening using a battery of small-scale or in vitro bioassays, which covered different modes of action, with detailed chemical characterisation based on gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/quadrupole time-of-flight mass spectrometry (LC-QTOF-MS). A large number of contaminants, belonging to different toxicant classes, were identified in both analysed matrices. Analyses of water samples showed that contaminants having polar character occurred in the highest concentrations, while in sediments, contributions from both non-polar and amphiphilic contaminants should be taken into account. Estimated contributions of individual contaminant classes to the overall toxicity indicated that, besides the classical pollutants, a number of emerging contaminants, including surfactants, pharmaceuticals, personal care products and plasticizers, should be taken into consideration in future monitoring activities. This work demonstrates the importance of the integrated chemical and bioanalytical approach for a systematic region-specific pollutant prioritisation. Finally, the results presented in this study confirm that hazard assessment in complex environmental matrices should be directed towards identification of key pollutants, rather than focusing on a priori selected contaminants alone. [ABSTRACT FROM AUTHOR]

This comprehensive field survey on indigenous European chub ( Squalius cephalus L.) presents, for the first time, site-specific variability of trace metal concentrations in the gut content, gastrointestinal tissue and two gastrointestinal sub-cellular fractions, operationally defined as metal-sensitive fraction (S50, which was isolated at 50,000 × g and contains total water soluble proteins), and metal detoxified fraction (heat-treated S50 (HT S50), which contains heat-stable proteins like metallothioneins). At five sampling sites along the Sava River in Croatia 1 to 5-year-old chub were collected in the post-spawning period (September) in order to estimate if metal concentrations in fish intestine are related to their levels in the gut content or fish age. Concentrations of essential metals (Zn, Fe, Cu, Mn) and non-essential Cd decrease in the gut content as follows: Fe > Mn > Zn > Cu > Cd, while in the gastrointestinal tissue: Zn > Fe > Cu ≥ Mn > Cd. Observed difference in metal abundance between the gut content and gastrointestinal tissue points to the selective metal absorption in fish intestine. Relationship among metal concentrations in the gastrointestinal tissue and two sub-cellular fractions (S50/HT S50) is significant for all analysed metals, with Spearman correlation coefficients ( r) at p < 0.01 for Zn 0.84/0.73, Cu 0.73/0.73, Fe 0.62/0.58, Mn 0.81/0.78, Cd 0.81/0.82. Site-specific differences point to the age-related increase of gastrointestinal Cu, Mn and Cd towards the downstream sites, while significant correlation between metal concentrations in the gut content and fish age exists only for Mn. In the sub-cellular gastrointestinal fractions, site-specific differences were not recorded on total water-soluble protein and metallothionein concentrations, which might be ascribed to the constitutional level. [ABSTRACT FROM AUTHOR]

Changes in habitat suitable for breeding of two sympatric raptor species ( Haliaeetus albicilla and Aquila pomarina) were analysed along one of the most important breeding sites in Croatia for both species. The habitat suitability modelling was used to assess the influence of forestry practice during 2000-2006 using the known data on nesting places along research area. The four most important variables for lesser spotted eagle were elevation, distance from the nearest pasture, vertical distance to the nearest channel network and broadleaved forest placement (second axis from the principal component analysis of the enhanced vegetation index (EVI) index of MODIS images; November-March). The variables where white-tailed eagles showed greatest shift from overall habitat characteristics in the research area were broadleaved forest (second axis from the principal component analysis of the EVI index), height above the sea level, distance from the small settlements, vertical distance to channel network - all with negative loadings. The results clearly reveal the disproportion of suitable forests for raptors that were cut down in comparison to maturation of suitable forests. [ABSTRACT FROM AUTHOR]

Sediment pollution of the biggest Danube tributary, the Sava River, was investigated within the sixth framework European Union project “Sava River Basin: Sustainable Use, Management and Protection of Resources” (SARIB). The extent of pollution was estimated by determining the amount of inorganic and persistent organic pollutants in sediment samples at 20 selected sampling sites along the Sava River. For the purpose of clarity, the findings are presented and published separately (part I: selected elements and part II: persistent organic pollutants). This study presents an investigation into the presence of organic pollutants in the Sava River sediment. According to the Water Framework Directive, the following persistent organic pollutants were investigated: polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), selected chlorinated pesticides and organotin compounds. The results reveal that PAHs were present in moderate concentrations (sum of 16 PAHs: up to 4,000 ng g − 1) and their concentrations increased downstream. Concen trations of PCB were low (sum of seven indicator PCBs: below 4 ng g − 1) and among the pesticides analyzed only p,p-dichlorodiphenyltrichloroethane was found in moderate concentrations at two sampling sites in Croatia (up to 3 ng g − 1) and hexachlorobenzene was found in a high concentration in the city of Belgrade (91 ng g − 1), although the use of these persistent pesticides has been banned for decades. Repeated sampling at the same location revealed point pollution near Belgrade. Among the organic pollutants surveyed, organotin compounds were not detected. Overall results reveal the presence of persistent organic pollutants in 20 of the Sava River sediments tested that is, in general, comparable or lower than the levels in the Danube River and other moderately polluted European rivers. [ABSTRACT FROM AUTHOR]

The construction or designation of detention areas along lowland rivers is considered along many European rivers. Since Croatia accommodates large detention areas, both natural (e.g., Mokro Polje) and controlled (Lonjsko Polje), it serves as an excellent example for planned detention areas elsewhere in Europe. This modelling study focuses on the controlled detention area of Lonjsko Polje. The flooding characteristics of the area are assessed in combination with the vegetation development and the transport and storage of sediment and phosphorus. Results of the modelling show that it is not so much the intake capacity that determines the flood duration time of a detention area, but the drainage capacity. A too long inundation duration following a flood event is shown to lead to major shifts in the vegetation composition. The results further indicate that about 30% of the sediment and adsorbed phosphorus that enters the detention area during an extreme (1:100 years) flood is retained within the area; this is about 10% of the total sediment and adsorbed phosphorus load of the Sava. Results of this study can be used to properly design and manage detention areas along lowland rivers. [ABSTRACT FROM AUTHOR]

Total concentrations of 13 elements (K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Y, Zr, Pb) in the size-fractionated Sava River sediments upstream and downstream of the Krsko nuclear power plant together with metal speciation within bulk sediment have been investigated. Trace metals generally increase with decreasing particle size, however, because of entrapment of organic matter in the 0.63-1 mm fraction, concentrations in the coarser sediment fraction are higher than expected. Exchangeable Pb, Zn, Cu, Mn, Cr and Fe are generally found to represent a negligible fraction of the total metal concentration of the bulk sediment. Seasonal variations of the Pb, Zn and Cu concentrations in the<0.5 mm fraction reflect decreased values during the spring period. Heavy metal concentrations in the 2003 waste water discharges from the Krsko nuclear power plant released into the Sava River were much lower than their maximum allowed values. Combined rubidium and organic matter normalization of the Zn, Pb and Cu concentrations, which was applied on the minus 0.063 mm fraction, indicated three potential sources of contaminants. [ABSTRACT FROM AUTHOR]

The radioactivity of water and sediments from the Sava river in the course through Serbia during 2001-2003 has been examined by alpha- and gamma-ray spectrometry. Except for cesium originating from Chernobyl, the radioactivity level of water and sediment coincide with the content of natural radionuclides in the environment of the river basin. Distribution coefficients as well as the runoff coefficient were determined for 137Cs. [ABSTRACT FROM AUTHOR]