Geochemistry aspects of modern mercury accumulation in bottom sediments from the south-western Chukchi Sea

Abstract

Mercury (Hg) having a high migration capacity reach the Arctic region via the atmosphere. The absorbers for Hg are sea bottom sediments. Sedimentation in the Chukchi Sea occurs under the influence of highly productive Pacific waters entering through the Bering Strait and the inflow of a terrigenous component from the western direction with the Siberian Coastal Current. The Hg concentrations ranged from 12 μg kg−1 to 39 μg kg−1 in bottom sediments of study polygon. Based on dating sediment core the background concentration was 29 μg kg−1. Concentration of Hg in fine sediment fractions was 82 μg kg−1, in sandy fractions (>63 μm) varied from 8 to12 μg kg−1. In recent decades the Hg accumulation in bottom sediments has been controlled by the biogenic component. The Hg in the studied sediments presents as sulfide form.