Abstract
Over centuries, mercury (Hg) has accumulated in the Arctic, primarily stored in permafrost soils and glacial ice. With climate change advancing at roughly twice the rate in the Arctic compared to the rest of the world [1], the accelerated melting of these natural reservoirs pose a significant risk. This process threatens to release large quantities of immobilized mercury, which, due to microbial activity in thawing permafrost, can also be transformed into methylmercury (MeHg), a highly toxic form that easily bioaccumulates in food chains. [2, 3]. This process may have far-reaching consequences for both terrestrial and aquatic ecosystems, disrupting food chains and potentially impacting human health in the long term. [3]
The ultratrace levels of mercury in seawater and meltwater present a substantial challenge, particularly for speciation analysis. Currently, there is a notable lack of data on Hg speciation, especially in remote Arctic environments, for example north-east Greenland. To investigate the speciation and release of Hg, we employ Gas Chromatography coupled with Inductively Coupled Plasma Mass Spectrometry (GC-ICP-MS), combined with species-specific isotope dilution (IDMS). [4] This study focuses primarily on the analysis of seawater, freshwater inflows, and ice samples, enabling us to accurately quantify and characterize various mercury species including inorganic Hg (iHg) and MeHg within these complex environmental matrices. The applied GC-ICP-MS method was optimized to allow the accurate IDMS-based quantification of the different Hg species at sub ng L-1 trace levels within the analysed water samples. Our analysis includes samples collected from Svalbard in 2023, as well as samples obtained during a cruise of the research vessel Maria S. Merian at different Greenlandic Fjords (2022). These efforts aim to fill the existing knowledge gaps regarding Hg species in critical Arctic regions, which are strongly impacted by the consequences of climate change.
