Contaminated sediments transported onto the river terrace during high water events can contribute significant quantities of potentially toxic elements to riparian soils. Seven trace elements (As, Cd, ...Cr, Cu, Ni, Pb and Zn) were analysed in the river sediment and riparian soil of the River Sava and their spatial distribution, potential toxicity and ecological risk levels were evaluated. The results showed that levels of all the trace metals were enriched to varying extents in both the sediment (As, Cr, Ni, and Pb) and soil (Ni) when compared to reference levels for sediments and European soils. Mean concentrations of trace metals in sediment and soil, apart from Pb, increased downstream in the River Sava. The similar increasing trend of these elements in sediment and soil may be explained by their increased load due to anthropogenic pressures (As, Cr, Ni, Pb and Zn in sediment and the significant accumulation of Ni in soil) and frequent periodic flooding (As, Cd, Cr, Cu, Ni and Zn in sediment and Cd in soil are influenced by both high water events and natural factors such as the geological substrate), particularly in lowland regions. In this study, soluble As, Cd, Cr, Cu and Ni fractions in sediment and soil <10% indicated their low mobility. The exceptions were readily soluble Pb and Zn in the sediment and soil at some sampling sites. In the lower reaches, levels of Pb in sediment was indicative of a medium environmental hazard, while there was a high environmental hazard in the upper reaches with the average Pb content in sediment higher than the PEL. Pollution factors for Pb in soil indicated a medium environmental hazard in the upper and middle reaches and a high environmental hazard at some sites in the lower stretches of the Sava River, although total Pb content in soil was within the range proposed for European soils.
•Riparian zone contamination was studied on a large spatial scale.•As, Cd, Cr, Cu, Ni, Pb, and Zn in riparian soil and river sediment were analysed.•Cr and Ni levels >PEL (CCME 2001) were found in river sediment in river's lower reaches.•Elevated As, Cr, Ni and Zn levels were found in riparian soil in river's lower reaches.•Hazardous readily soluble Pb in sediment and soil was found in upper reaches.
This study investigated the occurrence of 48 contaminants of emerging concern (CECs) in wastewater effluents from three Slovenian and three Croatian waste water treatment plants (WWTPs) representing ...the major inputs into the upper and middle course of the Sava River and simultaneously in the Sava River itself. Two sampling campaigns were carried out (May and July 2017). Samples were extracted using solid-phase extraction and analysed by gas chromatography - mass spectrometry. In effluents, 23 CECs were >LOQ with caffeine and the UV-filter 4-hydroxybenzophenone (H-BP) present in the highest concentrations (<49,600 ng L−1 and <28,900 ng L−1, respectively) and most frequently detected (detection frequency; DFr > 83.3%). Bisphenol B and E were detected for the first time in WW from Velika Gorica (May) and Zaprešić (July), respectively. In surface water (SW), 19 CECs were detected >LOQ with CAF again being the most abundant and most frequently detected (DFr = 92.9%). Bisphenols AP, CL2, P and Z were detected >LOQ for the first time in European SW. Active pharmaceutical ingredients naproxen, ketoprofen, carbamazepine and diclofenac; the preservative methyl paraben; CAF and UV-filter HM-BP were the most abundant CECs in SW and WW. An increasing trend in the total CEC load downstream was observed, indicating the cumulative effects of individual sources along the river. The Croatian Zaprešić, Zagreb and Velika Gorica WWTP effluents contributed the most towards the enhanced loads of the CECs studied probably due to their size or insufficient treatment. HM-BP was the only compound found at a levels exhibiting high environmental risk (RQ = 1.13) downstream from Ljubljana and Domžale-Kamnik WWTPs. Other SW samples that contained HM-BP, ibuprofen (API) and/or benzyl paraben (preservative) posed a medium risk to the environment. The results suggest the need for further monitoring of CECs in the Sava River Basin.
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•Bisphenols E and B were detected >LOQ in European SW for the first time.•Bisphenols AP, CL2, P and Z were detected >LOQ in European WW for the first time.•Correlation between CEC mass loads in Sava River and corresponding WWs was observed.•Overall CEC contamination downstream the Sava River was confirmed.•All SWs with detected HM-BP, IB or Be-PB posed at least a medium environmental risk.
We present a comprehensive study aimed to distinguish between natural and anthropogenic origin of some potentially toxic elements (PTEs: As, Cd, Cr, Cu, Pb, Sb, Sn and Zn) in soil, fine-grained ...sediment and suspended particulate matter (SPM) in the upper zone of the anthropogenically impacted Sava River (Slovenia, Croatia). The study area is also characterised by a diverse lithological composition and therefore has a wide range of geochemical compositions, which makes it quite challenging to determine the level of pollution in analysed materials. The local enrichment factors (LEFs) calculated for specific lithologies of the catchment such as Mesozoic carbonates, Neogene clastic sedimentary rocks as well as Paleozoic and Paleogene/Neogene siliciclastic rocks proved to be a good tool to reduce the grain-size effect and the signal of different provenances and finally to accurately identify the hotspots of pollution in the Sava catchment. For defined empirical functions, the LEFs of PTEs in background samples ranges: As (0.67–1.33), Cd (0.55–1.42), Cr (0.72–1.37), Cu (0.69–1.38), Pb (0.72–1.41), Sb (0.74–1.19), Sn (0.73–1.25) and Zn (0.73–1.42). There are still many sites impacted by past mining and smelting activities, but also untreated effluents with significant enrichment of Cd, Cu, Pb, Sb, Sn and Zn (LEFs range from 4 to 8; for the Voglajna River the LEF of Cd is ∼50 and of Zn ∼20) in the Sava zone and therefore require greater attention. This study improves our knowledge of the distinction between natural and anthropogenic sources of PTEs in sedimentary materials strongly influenced by different source lithologies that cause their contrasting geochemical signatures.
•Geochemistry of soil, fine sediment and suspended matter in an urban river was studied.•Lithology caused great variability in geochemical composition of sedimentary materials.•Local enrichment factors were used to identify pollution sources.•Cd, Pb, Sb, Sn and Zn showed many exceedances of background levels.
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•Time-integrated sampler is employed in medium-sized river and smaller tributaries.•Mineralogical and geochemical composition of the SPM depends on hydrodynamic ...sorting.•Representativeness of the SPM collected by TIMS is reasonably good.•Sampler efficiency can be diminished during high discharges.•Physicochemical changes inside TIMS can invoke additional modifications of the SPM composition.
The suspended particulate matter (SPM) carried by the rivers shows a wide range of particle size classes, mineralogical and chemical compositions and is mainly influenced by hydrodynamic sorting and provenance during the transport. Here, we have investigated the composition of the SPM in the Sava River and its tributaries (Ljubljanica, Savinja and Krapina) using a time-integrated suspended sediment sampler (TIMS). The representativeness of material collected by TIMS was evaluated comparing fine-grained sediments, single-point SPM and SPM collected using a shallow and deep-positioned sampler. The main results have revealed that the mineralogical and geochemical composition of the material is largely dependent on hydrological conditions. The differentiation of element composition is especially emphasized at low water stage when most of the SPM consists of slow-settling mineral phases (clay minerals and metal oxyhydroxides) which can be trapped in the sampler. During periods of high discharges, differentiation is less prominent, and homogenization of the SPM occurs, mainly as a part of bed load is also taken into suspension. These conditions have proven unfavorable for sampler efficiency, as at least part of the finest particles could not be retained. Additional issues that may occur during TIMS employment relate to biologically driven carbonate precipitation, which is triggered by changes in physico-chemical conditions at low water table in the summer period. Increased concentration of Ca, related to that process, influences the elemental composition of the SPM, which is particularly important when anthropogenic impact or sediment source is assessed. Hence, in order to interpret the geochemical and mineralogical data collected by TIMS, these factors should be taken into account. Our findings emphasize the need for detailed studies of chemical composition of the SPM (time-integrated) in medium-sized rivers and point out the significance of evaluating sampling representativeness during different hydrological conditions.
River ecosystems are exposed to various stressors. Among them, elements may contribute to overall pollution of riverine environments, in particular during the extreme flow events. To evaluate the ...influence of variable river flow conditions on the mobilization of potentially toxic elements (PTE) (Cr, Ni, Cd, Zn, Pb, As and Cu) from sediments into the overlaying waters of the Sava River, samples were collected in September 2014, during extremely high water discharges and in September 2015, under low water discharge conditions. In water samples the total element concentrations and the dissolved element contents (<0.45μm) were determined. Sediment pollution was estimated by determination of the total element concentrations and mobile element fraction (0.11molL−1 acetic acid). Anthropogenic inputs of elements to sediments were evaluated by normalizing elemental against Al concentration. The results showed that concentrations of PTE in water were in general higher during high water discharges, while the soluble concentrations were higher during low water level conditions. Concentrations of PTE in the Sava sediments collected in 2015 were lower than those collected in 2014, mainly because during the extreme floods a mixture of bank sediment material and contaminated soil was sampled. Partitioning coefficients between suspended particulate matter (SPM) and soluble content of elements in the water under high and low flow conditions, indicated on different affinity of elements to SPM in relation to different flow regimes. The potential ecological risk posed by the simultaneous presence of PET in sediments was evaluated by Probable Effect Concentration Coefficient (PEC-Q) approach. Under high water level conditions, PEC-Qs were all above critical value 0.34 and derived mostly from anthropogenic inputs of Cr and Ni. Overall sediment toxicity was much lower under low water discharges. The data from this study importantly contribute to the knowledge regarding the behaviour of PTE under extreme flow events.
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•Extreme flow events greatly influenced contents of PTE in water and sediments of the Sava River.•Under low discharges that followed big floods the contents of PTE in sediments were lower.•PTE in sediments were during big floods partially remobilised into overlying waters.•PTE exhibited different affinity to SPM in relation to different flow regimes.•Potential ecological risk posed by the simultaneous presence of PET in Sava sediments was moderate.
Field research conducted in the Peripanonian part of Bosnia and Herzegovina resulted in new and noteworthy records for the genus Lindernia. For the first time, alien L. dubia was recorded in Bosnia ...and Herzegovina, and new localities of threatened L. procumbens were also discovered. Individuals of both species grew in wetland vegetation of the class Isoëto-Nanojuncetea. The paper presents data on the morphology, ecology and distribution of species of the genus Lindernia. The alien status of L. dubia in Bosnia and Herzegovina is determined as the initial phase of naturalisation. The threatened status of L. procumbens in Bosnia and Herzegovina is assessed as endangered. These results contribute to a better knowledge of the flora and vegetation of ephemeral wetlands in Bosnia and Herzegovina, as well as the Balkans, which are still not sufficiently explored.
Coupled measurements of nitrate (NO3−), nitrogen (N), and oxygen (O) isotopic composition (δ15NNO3 and δ18ONO3) were used to investigate the sources and processes of N cycling, while the microbial ...source tracking (MST) method was used to identify microbiological pollution in the surface water of the Sava River Basin (SRB) in autumn in 2014 and 2015 during high and low water discharge. Atmospheric nitrate deposition or nitrate-containing fertilizers were found not to be significant sources of riverine nitrate in the SRB. The ranges of isotope values suggest that NO3− in the SRB derives from soil nitrification, sewage, and/or manure, which were further supported by MST analysis. Microbiological indicators show the existence of hotspots of fecal pollution in the SRB, which are human associated. Long-term observations indicate persistent fecal contamination at selected locations caused by continuous discharge of untreated wastewaters into the SRB.
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•There are spatial and temporal differences in nutrient concentrations in the Sava River Basin.•The combination of soil nitrification and admixture of nitrate from wastewater and manure are the main sources of nitrate in autumn.•Microbiological analyses showed the existence of hot spots of fecal pollution.•Microbial source tracking analyses confirmed that the pollution is human associated.
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.
During a sampling campaign in September 2015, elevated chromium (Cr) concentrations were observed in sediments of industrially exposed sites of the Sava River (stainless steel production and impact ...of metallurgic industry). To verify if sediments also contained hazardous hexavalent Cr (Cr(VI)), there was a need to develop a sensitive and reliable analytical procedure for its determination. In the determination of Cr(VI) in environmental samples, it is necessary to evaluate the suitability of the applied analytical methodology for each individual sample matrix. In these studies, the use of isotopically enriched Cr tracers importantly contribute to the validity of the obtained results. In the present work, an analytical procedure was optimised for the extraction of total Cr(VI) from sediments and the content of Cr(VI) determined by high performance liquid chromatography coupled to inductively coupled plasma mass spectrometry (HPLC-ICP-MS). To leach the total amount of Cr(VI) from sediments, an ultrasound-assisted extraction procedure was applied at 80 °C, using 2% NaOH + 3% Na2CO3 as the extraction solution. The addition of 0.4 mol L−1 MgCl2 prevented oxidation of Cr(III) during the extraction step. To control for species interconversion and for an accurate calculation of Cr(VI) concentration by speciated isotope dilution (ID)-ICP-MS, the alkaline extract was doubly spiked with enriched 50Cr(VI) and 53Cr(III). The accuracy of the determination of Cr(VI) was verified by analysing the certified reference material CRM 041 (Cr(VI) in soil), and by spike recovery test. Low limits of detection (LOD) and quantification (LOQ) (1.25 and 4.0 μg Cr(VI) kg−1, respectively) and good repeatability of measurement (relative standard deviation better than ±4.8%) were obtained. The analytical data revealed that Cr(VI) concentrations in sediments of the Sava River did not represent any known environmental hazard.
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•Procedure for the alkaline extraction of total Cr(VI) from sediments was optimised.•50Cr(VI) and 53Cr(III) isotopic tracers enabled to follow species interconversion.•Cr(VI) in Sava River sediments was determined by the speciated ID-ICP-MS.•In most of samples Cr(VI) was not detected, or its content was below 5 μg kg−1.•Concentrations of Cr(VI) in Sava sediments do not represent environmental hazard.
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