Fractionation of metals in the Sa1/2 sediment core from Lake Sarbsko (northern Poland) and its palaeolimnological implications

Abstract

This article documents and interprets stratigraphical changes in fractionation of Fe, Mn, Mg, K, Pb, Cu and Zn in the Sa1/2 sediment core from a coastal freshwater lake, Lake Sarbsko (northern Poland). The elements were sequentially extracted from the samples to distinguish five geochemical fractions: exchangeable, acid-extractable, reducible, oxidisable and residual. The analyses revealed substantial variations in geochemical partitioning of the elements and showed no correlation between the fractionation patterns and lithology of the sediments. In the sediments of Lake Sarbsko, iron is mainly bound to sulfides. Potassium occurs in its residual form. Magnesium and zinc are associated with carbonates and aluminosilicates, while copper occurs in compounds with organic matter and sulfides. Lead is found in connection with aluminosilicates and, to a lesser extent, with sulfides and organic matter. Manganese is partitioned between the oxidisable, acid-extractable, and exchangeable fractions. Heavy metals and potassium display the overall tendency to reduce the contents of their residual forms towards the top of the depositional sequence. Fe, Mn, Mg and Zn were found to be the most susceptible to post-sedimentary mobilisation.

Geochemical characteristics of Late Glacial and Holocene biogenic sediments in central Poland and implications for reconstructing the palaeoenvironment

“…It should be emphasised that the first two of these methods is not often used in research in the field of dynamic geomorphology and Quaternary geology due to its complete dissolution of silicates and resultant overestimation in reconstructed intensity of denudation processes. The ongoing discussion on the geochemical methods used relates to, among other things, research objectives, the nature of examined sediment, and technological progress in research equipment (Borówka 2007;Zgłobicki 2010;Woszczyk, Spychalski 2013); nevertheless, this paper presents the results of analyses of the chemical composition of sediments that were performed with the highest accuracy and, in order to obtain comparability of results, that employed uniform and consistent laboratory procedures described detailed by Borówka (1990Borówka ( , 1992 and . The outcome was a database of results of various geochemical parameters for nineteen sites within a relatively small area, which makes the study area unique among geochemically developed parts of the Polish Lowland.…”

“…Only then will it be possible to identify ingredients of allochthonous origin, autogenic ingredients and minerals of biogenic origin (Ewing, Nater 2003;Rydelek 2013;Kalińska-Nartiša, Gałka 2018). As a result, the multitude of distinguished components translates into a high diversity of types of biogenic sediments in the temperate climate zone (Borówka 2007;Kanbar et al 2021), and as many researchers correctly claim (Sobczyński, Siepak 1998;Woszczyk, Spychalski 2013) is a reason to distinguish and quantify the forms in which metals occur in reservoir sediments.…”

Lithology and geochemistry of the Late Glacial and Holocene sediments from Gostyń Lake (Western Pomerania, Myślibórz Lakeland)

“…An accelerated circulation of elements in numerous lakes was explained by developing settlements and catchment deforestation coupled with the use of copper products and mineral dyes (Cieśla, Stupnicka 1980;Hildebrandt-Radke et al 2011;Owsianny et al 2011;Forysiak et al 2012). However, Woszczyk and Spychalski (2013) demonstrated that the metals mentioned occur in the sediments in various forms (exchangeable, acid-extractable, reducible, oxidisable, and residual) which, in addition, could have been altered quantitatively during the Holocene. The authors mentioned are of the opinion that the three distinct shifts in the total content of trace elements and their total content in chemical fractions of the Lake Sarbsko sediment were caused by, inter alia, changes in sediment lithology and human impact.…”