Ecological-Geochemical Characteristics and Evolution of the Chemical Composition of Lake Karymsky after the Underwater Eruption in the Academii Nauk Caldera in January 1996 (Kamchatka Peninsula)

Based on the data acquired during the 2024 hydrochemical survey, taking into account previously published and archival material, the evolution of the chemical composition of Lake Karymsky was studied. The underwater eruption that occurred in the Academii Nauk caldera in 1996 had a significant impact on the hydrochemistry of the lake. It was seen as an increase in the concentration of all macrocomponents and a decrease in pH. Since 2015, there has been a stabilization of the chemical composition of the lake water. However, the concentrations of anions and cations remained higher compared to the data obtained before the onset of intensified volcanic activity. The lake water is enriched with a number of trace elements, including those that affect its quality. The trace elements were supplied by thermal waters that discharge along the coastline and at the bottom of the lake. Water quality does not meet the regulatory requirements for waters for domestic and drinking purposes; exceedances of maximum permissible concentrations (MPC) of harmful substances for waters for economic and fishery purposes have been recorded for a number of trace elements, including toxic ones (arsenic, boron).