The objectives of this study are as follows: (a) an assessment of the geochemical background signature of the Drava Valley before the industrial revolution; (b) an evaluation of anthropogenic ...geochemical influences on the alluvial plains and river terraces in the valley; and (c) a determination of the spatial distribution of trace elements in the alluvial soils of the Drava River downstream of the Austrian–Slovenian border to the confluence of Mura and Drava Rivers.
Samples of topsoil (depth of 0–5
cm) and subsoil (depth of 20–30
cm) were collected from 134 sampling sites on alluvial plains and river terraces. Analysis for 41 chemical elements was performed. Based on a comparison of statistical parameters, the spatial distribution of particular elements and the results of factor analysis, one anthropogenic and three natural geochemical associations were identified. The anthropogenic association (As–Ba–Cd–Mo–Pb–Sb–Zn) is mostly a result of historical zinc and lead mining and smelting in the Drava River watershed. The natural geochemical associations (Al–Fe–K–Co–Cr–Cu–Li–Ni–Rb–Sc–Th, Ti–Ce–La–Nb–Ta and Ca–Mg–Sr) were mainly influenced by lithology. The entire assessed area of about 130
km
2 is, according to Slovenian and Croatian legislation, critically polluted with trace elements, especially zinc.
► Mines and smelters contributed to the Drava alluvial sediments. ► One anthropogenic and three natural geochemical associations were identified. ► Al–Fe–K–Co–Cr–Cu–Li–Ni–Rb–Sc–Th, Ti–Ce–La–Nb–Ta and Ca–Mg–Sr are effects of lithology. ► As–Ba–Cd–Mo–Pb–Sb–Zn is influenced by historical zinc and lead mining and smelting.
Discharge of hazardous substances (HSs) in hydrographic basins represent a danger to aquatic biological activity and water supplies and can severely pollute surface water sediments. The increase of ...pollution in the Danube Basin requires the implementation of systematic monitoring and evaluation of the sediments quality as dictated by the EU Water Framework Directive. For this system development, applicable in mountainous conditions, the Upper Tisa region in the northwest part of Romania on the border with Ukraine, Hungary and Slovakia was selected as a test area. Sampling of overbank (floodplain) sediment, river bottom sediment and suspended sediment was carried out at 10 locations in the test area in order to analyze the concentration and distribution of eight metal(oid)s (Cu, Pb, Zn, Cd, Hg, Ni, Cr and As), in addition to 3 organic components (anthracene, fluoranthene, benzo(e)pyrene) as hazardous substances (HSs). The sediment quality assessment was carried out according to the 2013/39/EU Directive and EU Water Framework Directive standards. Most of the analyzed HS concentrations in river bottom sediment and overbank (floodplain) sediments fall within the limits of environmental quality standards (EQS). As, Cu, Pb, and Zn tend to exceed the EQS at some locations. The highest exceedances were recorded for Pb, for which contents of up to 987 mg/kg were detected. The highest contents were found in the overbank sediments sampled, and the lowest in river bottom sediments, which may indicate historical pollution. Mercury contents in overbank sediment samples exceed all standards, while cadmium content is below the international standards. Anthracene, fluoranthene and benzo(e)pyrene concentrations in overbank and bottom sediments comply with international standards. A few samples in suspended sediments slightly exceed the lowest environmental standard value (i.e., Romanian normal value). HS concentrations remain low in the suspended sediments showing that it is not the main transport route for pollution in this area. HS contents decrease gradually from upstream to downstream due to dilution along the river course. In the last testing point at Someș Aciua, the concentration of metal(oid)s measured in the sediments remain below the EQS limit values, thus there is no risk of transboundary pollution. The main source of metal(oid) contamination is historic base-metal ore mining and the associated mine waste sites in the Baia Mare and other mining areas scattered around the whole region. The main source of the studied organic compounds is the incomplete or low-temperature coal combustion processes that occur in households in rural areas
In the Eastern Croatia impressive loess-paleosol successions up to 30 m thick are exposed. In the Zmajevac I section three paleosols are intercalated in loess while in the Zmajevac, Erdut and ...Sarengrad sections there are four paleosols are intercalated in loess. IRSL age estimates of 17.8 plus or minus 1.9 and 217 plus or minus 22 ka. In all investigated sections, alluvial sediments are intercalated in the loess deposits, indicating periods of fluvial activity. Strongly abraded typical aeolian spherical grains characterized by pitted well-rounded surface that was developed during transportation have original crystal surface almost destroyed. Surface of quartz grains preserves micro textures characteristic for all transport medias that it has been exposed to. However, muscovite grain surface enable successful distinguishing if the last transport was by wind or by aquatic media. Characteristic of all horizons with muscovite as a dominant mineral is recent settling of organisms. Beside the Danube, Drava and Sava River flood plains, part of the analyzed sediments also originates from regional Tertiary sediments which are rich in granite (as a muscovite-bearing rock), indicating the local influence. Enrichment of pyroxenes in the Sarengrad section points to the Dinaride Ophiolite Zone as its source of origin eroded by the Sava River southern tributaries. Sarengrad section is the southernmost among the analyzed sections and the southern edge of the Carpathian Basin. Thus, beside the Alpine region, the mineral composition is influenced by minerals from the Dinaride Ophiolite Zone in Bosnia. Warming periods are not represented just by paleosols, but also with laminated alluvial sediments.
Loess is a widespread continental aeolian sediment. Groundwater generally represents the most important source of potable water in loess areas, where loess is the aquitard overlying the aquifer ...system. This work investigates loess deposits of eastern Croatia that overlie a sandy aquifer exploited for potable and agricultural purposes. The genesis of the deposit and the depositional and post-depositional processes affecting its structure were reviewed in this work and integrated with the estimated hydrogeological properties of the material to propose a preliminary hydrogeological conceptual model of the loess-sand system. The results of published granulometric analyses were used to calculate the effective porosity and the hydraulic conductivity of the material employing an analytical approach. The eastern Croatian loess is a silty deposit originated during Middle-Upper Pleistocene glacial periods. The sediments produced by glacial grinding were transported and deposited by the Danube fluvial system and subsequently remobilised by wind forming the loess. During the interglacial periods, the pedogenesis of the deposit occurred, with bioturbations and discontinuities by living organisms at the micro- and macro-scale. The deposition of a new loess layer compacted and consolidated the previously deposited loess leading to the development of a sub-vertical pore structure and sub-vertical cracks at the micro- and macro-scale, respectively. The calculations from the grain size distributions point to the low effective porosity (5-12%) and hydraulic conductivity (~10-9 m/s) of both loess and pedocomplexes supporting their aquitard behaviour. The infiltration of surficial waters and their flow toward the underlying sandy aquifer is locally enhanced by the post-depositional discontinuities that constitute preferential flow paths within the loess aquitard. These results highlight the need of detailed hydrogeological investigations in loess deposits to address the impact of post-depositional processes on their hydrogeological behaviour and the upscaling of their hydrogeological properties for proposing specific groundwater protection strategies in loess areas.
Previous studies on the mineralogical differentiation of Pleistocene loess/palaeosol sections focused on the description and source material of four loess/palaeosol sections located on the eastern ...border of Croatia along the Danube: Zmajevac, Zmajevac I, Erdut and Šarengrad. The authors demonstrated the decreasing influence of the Danube and the increasing influence of the rivers draining the Central Bosnian Mountains of the Dinaric Ophiolite Zone both important source areas for aeolian sediments at the southern edge of the Carpathian Basin that transport material from the Central Bosnian Mountains. The aim of this research is to identify the palaeoclimatic factors that influenced the pedogenetic development of the studied palaeosols. The model was created based on the research results of the same four loess/palaeosol sequences in Eastern Croatia. This model can also be applied in other locations to determine the influence of certain climatic factors on the degree of pedogenetic development of individual palaeosols. The loess/palaeosol sequences were divided into eight comprehensive groups (horizons) based on their genesis, degree of pedological development and/or position in the soil profiles. The explanation of the typical patterns occurring between the studied horizons is based on the construction of a Discriminant Function Model (DFM) resulting from the analysis of the compositional data (CoDa) of the geochemical (major and trace elements) and granulometric (grain size) data of the loess/palaeosols in combination with external variables such as weathering coefficients and chemical soil properties. In the final phase, the DFM was transformed from structural (mathematical) to functional (process) terms. This revealed that three main themes dominate the formation of Pleistocene loess/palaeosol sequences: 1) the separation of well-developed palaeosols from parent material; 2) the separation of automorphic palaeosols from hydromorphic soils exposed to post-pedogenic waterlogging conditions; and 3) the differentiation of horizons (soils and alluvium) formed by the redeposition (by water or mudflows) of previously deposited aeolian material, regardless of whether and to what extent it was exposed to post-sedimentary pedogenesis.
•Pedogenesis of loess/palaeosol sections explained by discriminant function model.•Soil formation defined by combination of compositional and external variables.•First discriminant function separates developed soils from parent material.•The 2nd discriminant function distinguishes between different types of pedogenesis.•High classification rate shows integrity of originally defined groups (horizons).
A 23m thick succession of Quaternary deposits was investigated at Zarengrad, Eastern Croatia. A geo- chronological study was performed on loess samples using luminescence dating. An elevated temper- ...ature post-IR infrared stimulated luminescence (post-IR IRSL) dating protocol was applied. Perform- ance tests showed that the protocol is suitable for the samples under study. The post-IR IRSL based chronology implies that, contradictory to previous correlations, a Middle Pleistocene loess-palaeosol sequence is exposed at Zarengrad II and not the Last Glacial - Interglacial cycle. Based on ages, the lowermost loess is correlated to oxygen isotope stage (OIS) 9-10 and the double palaeosol at the top of the section most likely correlates with OIS7. The Last Glacial record is exposed at the nearby Za- rengrad I section. Furthermore, a heavy and light mineral analysis was performed on the investigated section as well as on the previously investigated Zarengrad I section, showing that the mineral associa- tion is typical for Quaternary deposits of the Pannonian basin.
The loess-palaeosol record on the island of Susak in Croatia is a unique archive of Late Glacial climate changes in the Adriatic region, possibly even in the wider area. On Susak up to 90 m of thick ...Quaternary sediments were deposited, and are accessible for detailed palaeoclimate reconstructions. In this paper, the results of a high-resolution grain-size and rock magnetic investigation on the Last Glacial (Upper Pleniglacial) Sand Pit section from Susak are presented. In spite of its significant thickness, the Sand Pit section does not represent a continuous record; it is a result of a very dynamic environment. There, the deposition of dust and formation of loess has been interrupted by pedogenesis, periods of increased sand accumulation, erosion due to slope wash and water activity, redeposition and wildfires, and all in the time period of about 10.000 years of the Upper Pleniglacial, as seen from the IRSL dating results. The grain-size data clearly show a shift towards coarser grain sizes which differs from typical loess regions. Such predominance of the coarser-grained over the fine-grained fraction, very likely resulted from the predominance of deposition over pedogenesis, increased wind activity and proximal source of material. The rock magnetic signal preserved in the sediment also differs compared to loess-palaeosol records from other regions. The susceptibility values are several times higher than in the records from the Pannonian basin and from typical Eurasian loess. Both the increased susceptibility values and the grain-size are very likely the result of a significant proximal material input from the Po River plain.
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