ASSESSMENT OF MERCURY FLUX TO BOTTOM SEDIMENTS IN HIGH-ALTITUDE SMALL LAKES OF THE ALTAI MOUNTAINS (Ukok Plateau, Altai Republic)
V.I. Malov1,2, V.D. Strakhovenko1,2, M.A. Gustaitis1,2, E.A. Ovdina1, G.I. Malov1
1V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk National Research State University, Novosibirsk, Russia
Keywords: Mercury, mercury flux, Hg, bottom sediments, lakes, Altai
Abstract
This study presents the results of a comprehensive assessment of mercury content in the bottom sediments of four high-altitude lakes on the Ukok Plateau (Altai, Russia): Zerlyukol’-Nur, Krasnoe, Teplyi Klyuch, and Argamdzhi. The aim was to evaluate the mercury contents and mercury fluxes in the sediments as indicators of global atmospheric pollution. The Hg content varies from 28 to 130 ppb, averaging 57.4 ± 21.4 ppb, which corresponds to background values for high-altitude lakes of the Northern Hemisphere. The elevated Hg contents in the upper core layers of three lakes reflect postindustrial contamination, whereas this trend is absent in Teplyi Klyuch, likely because of a thermal endogenous influence. Sedimentation rates of 0.18 cm/yr in Teplyi Klyuch and 0.9 cm/yr in Argamdzhi yield mercury fluxes of 3.9 and 9.1 ng/(cm2∙yr), respectively, comparable to those reported for the southern Himalayas but lower than mercury contents in industrially active regions. The obtained data indicate that the Ukok Plateau remains isolated from direct pollution sources and is significant as a background indicator area for evaluating transboundary mercury transport. This work fills a data gap on Hg distribution in remote high-altitude ecosystems and refines global mercury cycling models.
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