Fish from the Sava River are consumed daily by the local people: therefore, concern has been raised about the health implications of eating contaminated fish. In the present study, potentially toxic ...elements (PTE), such as Zn, Cu, Cr, Ni, Cd, Pb, As, Hg, and methylmercury (MeHg), were determined in ichthyofauna that are commonly consumed. PTE were determined in the fish muscle tissue. Fish were sampled at 12 locations from the source of the Sava River to its confluence with the Danube River during two sampling campaigns, namely; in 2014 under high water conditions and in 2015 under normal water conditions. Due to the different water regimes, different fish species were collected for chemical analysis. We observed that the concentrations of elements analysed in the fish muscle tissue were generally very low, except for those of Hg. Moreover, more than 90% of Hg present in the fish was in its most toxic form, namely MeHg. Especially in fish from the 2015 sampling campaign, Hg and MeHg concentrations increased with fish size, trophic level, and in the downstream direction. In addition, for Pb and As, and to some extent for Cd and Cr, spatial differences were detected in both years. The highest concentrations of PTE were detected in fish from sites with intensive industrial and agricultural activities. The consumption of fish in general does not pose a health risk for the PTE studied, except for Hg/MeHg at selected contaminated sites.
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•Potentially toxic elements determined in different fish species from Sava River.•Potentially toxic elements concentrations were generally low, except for As and Hg.•Concentrations of As and Hg in muscle tissue increases in the downstream direction.•90% of Hg was present in its most toxic form, namely MeHg.•Estimated Daily Intake (EDI) for As and Hg exceeded Tolerable DI in the lower Sava
Knowledge of groundwater flow, and accordingly, groundwater residence time is immensely important for the sustainable management of groundwater resources. This requires a good conceptual model of the ...aquifer system. In this paper, a conceptual model based on the interpretations of hydrogeological and hydrochemical data, as well as measurements of environmental tracers (18O, 2H, 3H) was formulated for a semiconfined aquifer system in Eastern Slavonia in Croatia. The aquifer system is composed of Quaternary gravel and sand and silty–clayey interlayers and is covered with low permeability deposits. Measurements of water levels and environmental tracers in the study area clarified the groundwater flow evolution from the recharge area to the discharge area. The content of stable isotopes confirmed that the groundwater originates from precipitation. The tritium content and geochemical processes (such as cation exchange, silicate weathering) suggested a relatively long residence time of groundwater in the part of the aquifer system that is further from the Sava River. The same is confirmed by the results of calculated particle tracking pathlines.
•Recharge mechanism and groundwater flow evolution were studied.•Hydrogeological, hydrochemical and isotopic methods were combined successfully and used to improve conceptual model.•The results confirmed recharge by rainfall infiltration as the main source of water.•Groundwater residence time of several decades was confirmed by associated methods.
•Spatiotemporal variability in stable H and O isotope composition in surface water was observed in the Sava River Basin (SRB).•δ18O temporal variations of surface waters follow the pattern of ...precipitation with lower seasonal amplitude.•Mean residence time in river surface waters was estimated to be <2 years.•Complexity of spatial patterns of δ18O in precipitation over SRB was described by latitude, longitude and altitude.•Precipitation controls spatial variation of δ18O values in surface water across the SRB.
The presented paper describes spatial and temporal variations in extended stable isotope datasets of hydrogen and oxygen (δ2H and δ18O) in the Sava River water that were used to estimate the mean residence time (MRT) of stream water using an exponential flow model. The re-examining MRT was <2 years in the Slovenian part of the Sava River and was in a good agreement with previous estimates and with the MRT estimated in the Sava River at Ostružnica near Belgrade, Serbia. A MRT >2.2 years was observed in the Danube River at Vinča also near Belgrade. The spatial distribution of δ18O in precipitation over the Sava River Basin (SRB) was mapped based on the long-term weighted mean annual δ18O values and established relationship with various geographical controls (latitude, longitude and altitude). The modelled δ18O values in precipitation agree with the measured values in the surface river water at different locations indicating that the spatial variation in the isotopic composition of precipitation is the dominant factor controlling surface water isotope ratios over the SRB.
Biomarkers attract increasing attention in environmental studies, as a tool for detection of exposure and effects of pollution, from both natural and anthropogenic sources. This study aims to assess ...the impact of multiple stressors during distinctive seasons, covering also extreme hydrological events (extensive flooding in the mid May 2014), on different levels of biological organization in the liver and gills of three closely related freshwater breams. Our previous study on DNA damage in blood cells of these specimens showed increased DNA damage in June 2014, one month after the flooding event. As a continuation of that research, the present study was conducted. As a biomarker of exposure DNA damage was measured by applying the alkaline comet assay, while histopathological alterations were monitored as a biomarker of effect. Additionally, concentrations of metals and metalloids in gills, liver and muscle were assessed. Sampling of fish tissues was performed in 2014, during winter (January and February), spring (March and early June) and summer (late June, July and August). Significant seasonal difference in DNA damage was observed for both tissues. During spring and summer the level of DNA damage in gills was significantly higher when compared to the liver. Histopathological analyses showed higher frequency of alterations in gills during spring, and in liver during summer, but without a significant seasonal difference. Gills had the highest concentration of metals and metalloids during the spring and summer, and liver during winter. Muscle was the least affected tissue during all three seasons. This study highlighted the importance of the multiple biomarker approach and the use of different fish tissues in assessment of surface water pollution.
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•The impact of multiple stressors was studied by biomarkers response in fish.•DNA damage, histopathology and metal accumulation were studied in gills and liver.•DNA damage was higher in gills, changes in histopathology were prevalent in liver.•The variation of the biomarkers response depended on the sampling season.•Use of multibiomarker approach is essential for confident water quality assessment.
The Sava-Klepa Massif represents an approximately 5 × 2 km sized fault-bounded block of dominantly basaltic rocks located within the Sava-Zone, an important suture zone between the Eurasian (Europe) ...and Gondwana (Adria) continental plates in the Balkans. Its nature and tectonic evolution is controversial: It is either interpreted as a remnant of the youngest Tethyan oceanic realm left behind after the main closure in the Late Jurassic or as the delimiter of a diffuse tectonic boundary between Adria and Europe, which had already collided in the Late Jurassic and was dominantly controlled by transtensional tectonics during Cretaceous times.
In order to strengthen one or the other model, we concentrate on the Sava-Klepa Massif enclosing Paleozoic basement rocks, which mainly consist of a layered sequence of metamorphic marbles and mica schists. The metamorphic basement shows deformation structures clearly related to the Klepa event. Our results are based on paleostress and paleostrain analysis of twinned calcite from deformed marbles, and field observations, microstructural analysis, and 40Ar/39Ar dating of white mica. Paleostress and paleostrain analysis was enhanced by using an automated fabric analyser microscope, and developing the herein presented freeware standalone Windows® executable PACT software (Paleostress Analysis with Calcite Twins).
Our results support the hypothesis that the Sava-Klepa Massif was formed during transtension as a pull-apart basin in the Late Cretaceous. This could have happened either after the collision of the European and Adriatic plates, or along a transtentional zone in the fore-arc region during subduction of the last Tethyan oceanic lithosphere.
•Microstructural & paleostress data and 40Ar/39Ar dating on white mica to reveal the tectonic evolution of the Klepa-Massif•First simplified model of the Cretaceous tectonic evolution of the Klepa-Massif•PACT software for automated paleostress calculation based on calcite twin analysis
Given the increasing need to protect vulnerable freshwater ecosystems and make them more resilient to human use and climate change, biomonitoring of the hyporheic zone (HZ), which plays a critical ...role in pollution attenuation, is essential. The aim of the present study was to assess the potential of the amphipod species Synurella ambulans as a bioindicator of metal contamination in the HZ of the Sava River (Croatia). Amphipods were collected during the four seasons at two sampling sites (average sampling depth 55 cm) differing in type (agricultural and urban) and intensity (diffuse and point source contamination) of anthropogenic influence, one located upstream (Medsave), and the other downstream (Jarun) of the wastewater treatment plant discharge. Concentrations of Al, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Rb, Sn, Zn, Ca, K, Mg and Na were measured in the interstitial water, sediments and specimens of S. ambulans by HR ICP-MS. Physicochemical parameters (temperature, DO, O2 saturation, pH, conductivity, alkalinity, total water hardness, CODKMnO4, nutrients) were measured in the interstitial water, while organic carbon was measured in the interstitial water and sediments. Metal concentrations in interstitial water and sediments were below thresholds set by environmental quality standards. Metal concentrations in S. ambulans were classified as follows: higher at the Jarun site (Al, Cr, Fe, Ni, Pb, Sn), higher at the Medsave site (Cd, Cu, Rb) and mostly comparable at both sites (Co, Mn, Zn). Bioaccumulation factors were generally higher at Jarun, with average values ranging from 322 to 143,278 L kg−1. Bioaccumulation of metals in S. ambulans depended on various environmental factors, with metal exposure level and dissolved macro elements showing the strongest association with metals accumulated in S. ambulans. The findings provided the first evidence on the suitability of S. ambulans as a good bioindicator of chronic metal contamination in the HZ.
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•Synurella ambulans was sampled seasonally in hyporheic zone (HZ) in agricultural and urban area.•Metal concentrations in S. ambulans showed various spatiotemporal patterns.•Metal concentrations in S. ambulans strongly correlated with exposure levels in water.•Metals accumulated in S. ambulans strongly associated with dissolved macro elements.•S. ambulans is suitable for biomonitoring of chronic metal contamination in HZ.
Data from approximately 500 boreholes and an additional 40 wells for which there is a plausible range of data, facilitate description of the geometry of the Quaternary aquifer and its characteristics ...respectively, and pretension of the elements of the conceptual hydrogeological model in the Sava River valley. The aquifer heterogeneity is caused by tectonic activity and the depositional environments of the sediments within the valley. In the wider Zagreb area, gravel is the dominant component of the aquifer. Downstream from Zagreb, the aquifer is composed mainly of sand with sporadic intercalations of gravel. An admixture of silt and clay is not uncommon within the sand. The exceptions are alluvial fans that were formed by the right tributaries of the Sava River; gravel with sand is dominant in their lithological composition. The best hydrogeological properties of the aquifer system were registered in the vicinity of the Sava River, so all large pumping sites are located close to the river. The Quaternary aquifer is the main source of the water supply in the Sava River valley.
Within the field of geological analysis of subsurface data, some input may be scarce and include a small set of data. Such a data set is under-sampled and mapping algorithms result in uncertain ...outcomes. It then becomes necessary to obtain a reliable statistical data set of individual geological variables. The possibility of applying the bootstrap method on variables that are relevant in the exploitation and production of hydrocarbons, specifically the porosity and total cost of disposal formation water variables, was analyzed. The case study was carried out on the data of reservoir "K", field "B" located in the Western Sava Depression, Northern Croatia. The results highlight the appropriateness of applying the bootstrap method as a tool for defining uncertainty intervals on each sampled location. It is also dependent on resampling data set sizes, which is shown in three examples. The determination of uncertainty intervals for both studied variables gives crucial information for future development projects involving mature hydrocarbon reservoirs, and can be further applied in all similar Upper Miocene proven sandstone reservoirs in Northern Croatia. The porosity of the "K" reservoir is 0.2182 to 0.2506 at a resampling size of 2000, while the cost of disposal formation water value for field "B" is 2.31 to 2.69 USD/m
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at a resampling size of 1000.
We present a first synoptic view of the seismotectonics and kinematics of the eastern sector of the European Alps using geodetic and seismological data. The study area marks the boundary between the ...Adriatic and the Eurasian plates, through a wide zone of deformation including a variety of tectonic styles within a complex network of crustal and lithospheric faults. A new dense GPS velocity field, new focal mechanisms and seismic catalogues, with uniformly re-calibrated magnitudes (from 1005), are used to estimate geodetic and seismic deformation rates and to develop interseismic kinematic and fault locking models. Kinematic indicators from seismological and geodetic data are remarkably consistent at different spatial scales. In addition to large-scale surface motion, GPS velocities highlight more localized deformation features revealing a complex configuration of interacting tectonic blocks, for which new constraints are provided in this work accounting for elastic strain build up at faults bonding rotating blocks. The geodetic and seismological data highlight two belts of higher deformation rates running WSW-ENE along the Eastern Southern Alps (ESA) in Italy and E-W in Slovenia, where deformation is more distributed. The highest geodetic strain-rates are observed in the Montello-Cansiglio segment of the ESA thrust front, for which the higher density of the GPS network provides indications of limited interseismic locking. Most of the dextral shear between the Eastern Southern Alps and the Eastern Alps blocks is accommodated along the Fella-Sava fault rather than the Periadriatic fault. In northern Croatia and Slovenia geodetic and seismological data allow constraining the kinematics of the active structures bounding the triangular-shaped region encompassing the Sava folds, which plays a major role in accommodating the transition from Adria- to Pannonian-like motion trends. The analysis of the seismic and geodetic moment rates provides new insights into the seismic potential along the ESA front.
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•GPS and seismological data show consistent kinematics in the eastern Alps•Kinematics and tectonics result from the interplay of several tectonic blocks•GPS show new evidence for active deformation across faults•Limited interseismic coupling found for the Montello-Cansiglio thrust faults•New insights into seismic potential from seismic and geodetic moment rates
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