Trace elements in the bottom sediments of the Irkutsk Reservoir

Abstract

The chemical composition of bottom sediments of the Irkutsk Reservoir was examined. Ten sediment samples collected at different depths in four sectors of the Reservoir were analysed in a laboratory. Concentrations of 30 trace elements were determined. The purpose of the study was to assess the anthropogenic impact on the Reservoir geosystem. Barium and zirconium had the highest concentration in the sediments. Concentrations of certain elements varied spatially, while those of others were similar in all the sectors sampled. The highest element concentrations were usually found in sector 3 (in the vicinity of Novogrudinina). Maximum concentrations for around a dozen elements exceeded the geochemical background level for sedimentary rocks and the soil environment. Irkutsk Reservoir sediments exhibited a high concentration of chromium when compared with sediments from various other reservoirs impounded by dams. The study has shown that the environment of the Irkutsk Reservoir is subject to local and regional anthropogenic impact.