Authors:Péter Sipos, Tibor Németh, Chung Choi, Zoltán Szalai, and Réka Balázs
Knowledge of the distribution and sorption characteristics of trace metals in soils is essential because of their importance both from agricultural and environmental point of view. In this paper, an overview will be provided on the relationship between the behavior and sorption properties of Cu and Pb as well as major soil characteristics, based on the results obtained by several independent research projects carried out on this field at the Institute for Geological and Geochemical Research over the last 15 years. These projects were accomplished using methods with different approaches, e.g. studying metal characteristics by total metal content, selective chemical extractions and batch sorption experiments.Our results show that both metals can be found in soils, primarily in the form of phases highly resistant to weathering. However, if they are mobilized, they are easily and strongly immobilized by soils rich in organic matter, with higher affinity for Cu than for Pb. In acid soils, on the other hand, the leaching of Cu is expected to be higher from such horizons when compared to Pb, especially when iron oxides, which immobilize Pb preferentially, are also present in these horizons. In mineral horizons the close association of Pb and iron oxides can be still expected, whereas Cu prefers to be bound both by clay minerals and iron oxides. In alkaline soils, however, precipitation of both metals as carbonates is a general feature. Our results obtained through different approaches presented in this paper were found to be effectively complementary to each other, providing a much deeper insight into soil-metal interaction than when they are used independently.
Authors:Attila Demény, Gabriella Schöll-Barna, Pál Sümegi, Péter Sipos, and Brigitta Réka Balázs
In this paper we present sedimentological and geochemical data for a section of fluvial deposits from SE Hungary covering the period of 25 to 5 ky BP. Major and trace element geochemistry of bulk sediments as well as stable C and O isotope compositions of the carbonate content indicate significant changes in depositional facies and/or sediment provenance. Correlations of mineralogical and geochemical compositions were used to determine the stable isotope compositions of authigenic calcite component. Additionally, C and O isotope compositions of Unio crassus shell fragments were analysed that show a good agreement with climate change. Major climate change events within the studied time period were detected both in the shells and the authigenic calcite's compositions.
Authors:Attila Demény, Gabriella Schöll-Barna, Pál Sümegi, Péter Sipos, István Fórizs, Brigitta Réka Balázs, Bernadett Bajnóczi, and Gordon Cook
In this paper we present sedimentological and geochemical data for a section of fluvial deposits from SE Hungary covering the period from about 20 to 5 ky BP. Major and trace element geochemistry of bulk sediments as well as stable C and O isotope compositions of the carbonate content indicate significant changes in depositional facies and/or sediment provenance as well as climate conditions. Variations in bulk sediment Sr, TiO2 and P2O5 concentrations were correlated with major climate change events following the Late Glacial Maximum that support the age model established on the basis of AMS 14C age data. Bulk sediment Sr concentrations and stable C and O isotope compositions of bulk sediment carbonate were determined by changes in denudation of carbonate rocks in the recharge area. The Sr and C-O isotope patterns show correlations with global temperature changes during the Pleistocene-Holocene transition. However, TiO2 and P2O5 contents show correspondence with humidity changes, suggesting variations in chemical weathering. In addition to the sedimentological effects, C and O isotope compositions of Unio crassus shell fragments show strong changes at the Pleistocene-Holocene transition, indicating that the bivalve shells can reflect climate conditions. On the other hand, shorter climate change events were difficult to track in the isotope records due to the competing fractionation processes. The combined evaluation of chemical and isotopic compositions revealed that beside the globally important Younger Dryas and Bølling/Allerød periods, the Ságvár-Lascaux interstadial was of local importance, in accordance with earlier studies.