Accumulation level and fractions of heavy metals in sediments of small lakes of the urbanized area (Karelia)

Abstract

A detailed analysis of the environmental geochemistry features of the sediments of two small lakes located in Petrozavodsk city was presented. Samples of lakes were collected in 2016 and 2018 using a peat drill for deep layers of sediments and a sampler Limnos for modern layers of deposits. In the laboratory, after the drying and abrasion of samples until the powder condition, sediments were measured by an X-ray fluorescence spectrometer and mass-spectral method on a ХSeries-2 ICP-MS instrument. To have an environmental interpretation of results the sum indicator of pollution and index of geoaccumulation were calculated for each waterbody. The results showed the lake sediments of Petrozavodsk have different geochemistry features and various levels of pollution of heavy metals. In comparison with the background, such metals as Pb, Sb, V, Cu, Zn, W, and Bi have the highest level of accumulation in Petrozavodsk’s lakes. At the same time, the sediments of lake Chetyrekhverstnoye characterized by pollution from low to middle level and the sediments of lake Lamba have a pollution level from low to extremely high values. Almost all metals are predominantly in mineral phases, however, metals significantly have an association with organic matter and exchange fractions that present dangerously due to the migration of pollutants in systems “from sediments into the water” and “from sediments into biota”.