Heavy Metal (As, Cd, Cu, Hg, Pb and Zn) Distribution in Topsoil Developed on Alluvial Sediments of the Drava and Sava Rivers in NW Croatia

In the region of north-western Croatia (NWC) 328 topsoil samples were taken (from a depth of 0 to 25 cm). The composite samples were analyzed after near total decomposition (a hot acid mixture: HClO4–HNO3–HCl–HF at 200°C) by ICP–AES for As, Cd, Cu, Pb and Zn. Hg was analysed by cold vapour AAS. The following element concentration ranges were acquired: As 2–74 mg/kg (geometric mean 8 mg/kg), Cd 0.4–9.4 mg/kg (geometric mean 0.4 mg/kg), Cu 5–248 mg/kg (geometric mean 22 mg/kg), Hg 5–4,535 mg/t (geometric mean 55 mg/t), Pb 15–699 (geometric mean 32 mg/kg) and Zn 28–1,432 (geometric mean 82 mg/kg). The analysis of the spatial distribution of heavy metals in NWC showed increased values of As, Cd, Hg and Pb at Mts. Zumberak, Medvednica, Ivanscica and Kalnik that originate mainly from natural sources (bedrock mineralizations and ore deposits). The Cu and Zn contents on Mt. Medvednica are only slightly less natural in origin. The high concentrations of copper on the slopes of Mts. Zumberak, Medvednica, Kalnik and in the NW part of Hrvatsko Zagorje are of anthropogenic origin and are related to wine-growing areas. In the Sava River valley the average levels of Hg, Zn, As, Cd, and Pb are higher than the calculated baseline values (geochemical background) in the NWC while the Cu values are equal to the baseline values. The higher values of As, Cd, Pb, and (in part) Zn are for the most part of anthropogenic origin, and to a lesser extent of natural origin. The Hg in the topsoil has a strong anthropogenic influence caused by mining upstream (Litija) and by the city of Zagreb’s urban area (fossil fuel combustion, traffic, electrolysis, diverse paints, pharmaceutical products, chlor-alkali industry and paper industry). The pedogenic profile shows that the content of Cd, Pb, Cu and Zn at a depth of 20 cm is almost half the content of the same elements found in the first two centimeters of the soil. At a depth of 60 cm, the concentrations are in the level of background values characteristic of the preindustrial era. When compared to the calculated baseline values, the contents of As, Cd, Cu and Hg in the soils of the Drava River valley are higher, while the Pb and Zn contents are anomalous. According to permitted concentrations of heavy metals for ecological food production prescribed by Government regulations the contents of As, Pb and Zn in the topsoil on the Drava alluvial sediment are too high. The Cu concentrations are lower than the limit permitted by Government regulation. The higher contents of mercury, although under the limit prescribed by Government regulation, are an immediate consequence of fossil fuel combustion and traffic in the urban area of the city of Varaždin. Factor analysis and high correlation coefficients show a mutual connection of Pb, Zn and Cd (Pb and Zn r=0.96; Pb and Cd r=0.80; Zn and Cd r=0.84). These 3 heavy metals show high positive factor loadings on the first factor (F1) which accounts for more than 58% of the data variability. The flood waters of the Drava River were highly loaded with anthropogenic Pb, Zn and Cd mainly as a consequence of mining, smelting and flotation activities upstream in the Meza valley in the Republic of Slovenia and Austria. Also, they were additionally loaded with waste waters from upstream settlements. The soil profile shows that increasing depth results in the lowering of the Pb, Zn, Cd and As content reaching the background level of that area at 80 cm depth. This suggests that the alluvial sediments of the pre-industrial era lay deeper

Geochemical Baseline Mapping of Soils Developed on Diverse Bedrock from Two Regions in Croatia

The comparison of contents and distribution maps for Al, As, Ba, Ca, Co, Cr, Cu, Fe, La, K, Na, Ni, Mg, Mn, P, Pb, Sc, Sr, Ti, Th, V, Y, Zn and Hg in the topsoil cover of two typical regions are given. One is a carbonate bedrock (karst) dominated region (southern Dalmatia) and the other a non-carbonate bedrock dominated region (NW Croatia). The results imply that the soils developed on carbonate bedrock have higher mean values of almost all elements excluding K, Na, Mg and Ba, which are lower in carbonate terrains. In comparison with the non-carbonate terrains, for the carbonate terrains the following elements have higher mean concentrations: Al, As, Co, Cu, Fe, La, Mn, Pb, Ni, Mn, Th, V, Cr, Zn, Zr and Nb, while Sr, P and Ti have similar contents. Approximately 4% of the sites can be considered as moderately enriched (polluted) in Pb, either from mining activities or airborne deposition. Only a limited number of sampling sites can be directly linked with mineralization. The derived factors are usually interpreted as associations of elements that imply a common source or behavior in regard to geogenic or anthropogenic influences. It was found that difference between the northwestern Croatia and southern Dalmatia is not expressed only by concentration differences but also by element associations. Five factor models accounting most of the data variability seemed appropriate to portray the geochemical variability within the topsoil of both region

A Factor Model of the Relationship between Stream Sediment Geochemistry and Adjacent Drainage Basin Lithology, Medvednica Mt., Croatia

A mathematical model is constructed to relate the geochemical composition of recent stream material in a number of catchments on Medvednica Mt. to a broadely defined bedrock lithology which represents the parent material for the former. It is a system based factor model, which synthesizes eight lithological and 25 geochemical variables (major, minor and trace elements), reducing their relationships to six geologically meaningful factors. Five of these divulged a definite relationship between geochemistry and lithology. These are labelled as follows: factor of metamorphic rocks; factor of igneous rocks; factor of Tertiary carbonate rocks; factor of parametamorphic rocks and factor of Mesozoic carbonate rocks. Two lithologies; the Mesozoic clastic rocks and Quaternary sediments showed no clear association to any of the factors. Alternatively, one of the factors (F2) can be identified as “non-lithologic” indicating other, perhaps anthropogenic, contributions to the stream sediment geochemical composition

A 180 ka record of environmental change at Erdut (Croatia): a new chronology for the loess–palaeosol sequence and its implications for environmental interpretation

While there are numerous thick loess–palaeosol sequences preserved across the Carpathian Basin, well dated sites that provide terrestrial palaeoenvironmental records extending beyond last glacial–interglacial cycle are scarce. Robust chronologies are essential for correlations of loess with other long‐term Quaternary records and to further understanding of the palaeoenvironment and climate of this important region beyond the last 125 ka. Here a new geochronology based on 13 post‐infrared infrared stimulated luminescence ages focused on the lower part of the loess–palaeosol sequence at Erdut is presented. The results show that the lower part of the Erdut profile spans the penultimate glacial cycle (MIS 7 to MIS 5). The considerable sediments overlaying the investigated part of the profile suggest that this section spans two glacial cycles, rather than the previously suggested one. The most likely source of the discrepancy is the use of uncorrected infrared stimulated luminescence signal, which can cause age underestimation if not accounted for. This study demonstrates the need to revisit sites such as Erdut, re‐date them using updated measurement protocols, and update existing palaeoenvironmental interpretations