Mercury and organic matter content in bottom sediments of the Barents and Kara Seas

This study aims to obtain new data on the content of total mercury (Hg) and organic matter (OM) in bottom sediments (BS) of the Barents and Kara Seas, as well as an assessment of the relationship of these parameters. The material for this study: The research material was samples of BS selected during the expedition of the scientific research vessel Akademik Nikolay Strakhov from June 25 to July 28, 2019 in the Barents and Kara Seas when performing the tasks of studying BS and assessing the anthropogenic impact on ecosystems. Novelty : The paper presents new original materials on the study of the content of total Hg and OM in BS of the Barents and Kara Seas, as well as an assessment of the relationship of these parameters for marine soils of these Arctic waters. Methods used : the total mercury content in the samples was estimated by the method of flame-free atomic absorption on the mercury analyzer RA-915M (Russia). The determination of the relative content of organic matter was performed in accordance with Russian standard (GOST 23740-2016) by the gravimetric calcination method to a constant mass (“Loss on Ignition”). Statistical data processing and charting were carried out in the MS Excel 2016 environment and the Statistica 13. Results : The results of a study of the content of total Hg and OM in the BS of the Barents and the Kara Seas are presented. In the BS of the Barents Sea, the Hg content varied from 13.95 to 50,15 μg/kg with an average value of 29.5 μg/kg of dry sediment, and in the BS of the Kara Sea – from 17.25 to 52.79 μg/kg with an average value of 37.5 μg/kg. The OM in the BS of both seas turned out to be approximately the same and amounted 2.4-2.6%. For the Barents Sea, a correlation has been established between the content of Hg and OM. The increased total Hg content in the BS of the Kara Sea probably reflects the contribution of the regional component. Practical relevance : The results obtained will make it possible to better understand the processes associated with global mercury pollution of ecosystems in the Arctic.