Abstract Antarctica, although one of the planet’s most pristine regions, is not exempt from global pollution such as mercury (Hg), an element with a complex biogeochemical cycle. Hg emissions originate from natural and anthropogenic sources, and its long atmospheric residence time allows transport to remote regions. Polar regions act as sinks for Hg, particularly in ice-free areas where periglacial processes are dominant. Fildes Peninsula (King George Island) is one of the most densely populated areas in Antarctica with permanent scientific bases, an airport, and seasonal tourism, which increases environmental impacts. There are few in-depth studies on Hg in Antarctic soils, making it crucial to improve understanding of Hg behaviour and distribution within soil profiles from site-specific areas. This work examines Hg distribution in eleven soil profiles on Fildes Peninsula, identifies relationships between Hg and physicochemical soil parameters and evaluates potential drivers controlling Hg distribution. The results show three groups of soil profiles based on Hg depth patterns and soil properties: (1) neutral profiles in which Hg decrease with depth, where Hg is mainly associated with external inputs such as erosion processes, volcanic eruptions, periglacial processes, ocean aerosols, rainwater and/or snowmelt; (2) neutral profiles in which Hg increases with depth, where Hg is mainly linked to the parent material; and (3) ornithogenic profiles, where Hg is primarily related to organic residues derived from ornithogenic inputs. Furthermore, some profiles show evidence of anthropogenic influence from combustion emissions. Overall, organic matter, iron oxides and zeolites act as important Hg drivers across all analyzed profiles. Graphical Abstract The graphical abstract summarizes the main results of the study by illustrating observed mercury (Hg) depth patterns in Antarctic soil profiles and the soil properties controlling their distribution. Maps of Antarctica indicate the locations of the sampled sites, providing the geographical context of the investigation. The central part of the graphic presents representative soil profiles showing three distinct Hg depth trends identified in the study: neutral soils with decreasing Hg concentrations with depth, neutral soils with increasing Hg concentrations toward the parent material, and ornithogenic soils characterized by Hg enrichment associated with organic residues from bird activity. Upward- and downward-pointing triangles indicate Hg concentration changes with depth and are illustrated using field photographs of the sampled profiles. Potential Hg sources (atmospheric deposition, volcanic inputs, erosion processes, anthropogenic combustion, and organic residues) are shown as external inputs. The key drivers identified by the study—organic matter, Fe₂O₃, and zeolites—are highlighted as the main controls governing Hg retention and vertical redistribution within the soil profiles. Arrow thickness indicates the relative influence of these drivers on the different soil types.
Sierra-Herraiz et al. (Tue,) studied this question.