Granulometric and Chemical Composition of Bottom Sediments in North Kazakhstan’s Water Reservoirs: Implications for Soil and Water Management

Abstract

Bottom sediments play a crucial role in the environmental and agricultural management of freshwater reservoirs, acting as repositories for organic matter, chemical elements, and potential pollutants. This study investigates the chemical and granulometric composition of bottom sediments in the Verkhnetobolskoe and Karatomarskoe reservoirs in North Kazakhstan, focusing on the relationships between sediment particle sizes, organic matter, and heavy metal content. Sediment and water samples were collected during winter under ice-covered conditions using specialized sampling equipment and analyzed with advanced spectrometric and analytical methods. The study reveals significant correlations between fine-grained sediment fractions (<0.16mm) and the accumulation of organic matter and heavy metals, including cobalt, arsenic, and chromium, which exceeded permissible concentration limits. These findings underscore the ecological importance of fine sediment fractions as adsorptive sites for pollutants. The study concludes with methodological recommendations for sediment quality assessment and provides baseline data for environmental monitoring and agricultural planning in temperate freshwater ecosystems.