The Micro/elemental Composition of Bottom Sediments of Small Lakes as Indicator of Environmental Risks in Urban Area of Republic of Karelia
The general questions of the influence of urban environment on the development of deviations in living organisms up to the death of individual species are considered. Using the example of a study of the chemical composition of bottom sediments of six small lakes of the Republic of Karelia, a significant effect of technogenesis on the occurrence of ecological risks on the aquatic flora and fauna of an urbanized environment is shown. We have stated that the upper layers of the bottom sediments of urban lakes have increased concentrations of heavy metals in comparison with the underlying layers. The thickness of technogenically altered lake sediments for urban water bodies of Karelia is established. According to the analysis of the formulas of geochemical associations of bottom sediments of urbanized lakes, we identified priority pollutants (Pb, Sb, Cd, V, Zn, Cu, Ni etc.). These metals are associated with major environmental risks within the urban environment of the region. The patterns of distribution of individual chemical elements in the investigated lake sediments are determined depending on the geochemical specificity of the catchment area and specific sources of heavy metals. Examples of direct negative effects of heavy metals on living organisms of the aquatic environment are benthic organisms and fish. The biogeochemical potential of biota of urban water bodies to accumulate heavy metals and accompanying microelements is shown.