Assessment of Contamination and Accumulation of Heavy Metals in Sediments of Lake Issyk-Kul

Issyk-Kul is one of the largest continental highland lakes, known for its considerable depth and unique water homogeneity. Due to its rich history, favourable environmental conditions and unique geographical location, the lake is of significant value for Kyrgyzstan. The present study assessed the levels of heavy metal pollution and their accumulation processes in the bottom sediments of the lake. Sediment samples were collected from six locations around the lake: Balykchy, Chok-Tal, Cholpon-Ata, Bosteri, Tyup and Ottuk. The concentrations of 16 heavy metals were analyzed using ICP-OES. Pollution factor (CF), geoaccumulation index (Igeo), degree of pollution (Cd) and pollution index (PLI) were calculated from the data. The sediments in most points were moderately contaminated, but significant contamination was detected in the Tyup area. The sediments of Cholpon-Ata showed a low level of chromium contamination, otherwise, they remained clean. Among the toxic elements, moderate contamination was found for Vanadium (V) and Chromium (Cr), while elements such as Co, Cu, Ni and Zn showed low levels of contamination. The results of the study confirm the necessity of continuous monitoring of heavy metal concentrations in the bottom sediments of Lake Issyk-Kul and putting in place measures to prevent their accumulation.