Scientific publications

The paper reports the results of the analysis of Pb, Sb, Cd accumulation in top core sediments from small lakes of southern Republic of Karelia. Both lakes in urban areas (Petrozavodsk, Medvezhyegorsk, Suojarvi, and Sortavala) and lakes in areas regarded as reference for southern Karelia were included in the study. Fieldwork and analytical investigations employed a common methodology in line with globally-accepted limnological practices. The concentrations of chemical elements in the lake sediments were determined by inductively coupled plasma mass spectrometry (ICP-MS). The median background concentrations of Pb, Sb, Cd in the studied sediments deposited in the preindustrial period were calculated, and the recent levels of accumulation of these metals in the industrial period were determined for the same lakes. The main factors for the formation of technogenic Pb, Sb, Cd anomalies in the top core sediments are described, and the levels of the heavy metals are compared against those in lake sediments in other parts of the world. The levels of contamination of the Karelian lakes with these metals were calculated based on the geoaccumulation index Igeo. The Tessier sequential extraction procedure was employed to detect the main forms of the heavy metals in the top core sediments. Especially, the role of organic matter, which constitutes the bulk of the sediments, in binding the pollutants was assessed. Considering that Karelian lake sediments are potential sources of useful organic raw material, i.e. sapropel, some recommendations are given on the possible applications of these sediments in human activities.