Søndergaard Jens, Elberling Bo, Sonne Christian, Larsen Martin Mørk, Dietz Rune
Department of Ecoscience, Aarhus University, Frederiksborgvej 399, Roskilde, DK-4000, Denmark.
Department of Geoscience and Resource Management, University of Copenhagen, Øster Voldgade 10, Copenhagen K, DK-1350, Denmark.
Nat Commun. 2025 Jun 12;16(1):5135. doi: 10.1038/s41467-025-60356-6.
Anthropogenic activities have caused large-scale mercury (Hg) pollution in the Arctic reaching toxic levels, but knowledge of sources and pathways is sparse. Here, we present Hg stable isotope data in peat and key aquatic predatory species collected across Greenland. We observe distinct regional differences with significantly lower total Hg and higher δHg in central-western versus northern-eastern Greenland influenced by different ocean currents. While ΔHg shows that atmospheric Hg deposition occurs predominantly (60-97%) as Hg(0), ΔHg reveals marked photochemical demethylation in especially freshwater habitats. We find δHg in muscle tissue to increase with trophic level linked to internal metabolic transformation. Finally, we observe significant increases in total Hg and δHg for several species/sites during the past 40 years, suggesting an increase in anthropogenic Hg sources and/or change in environmental processes. These findings show that ocean currents carrying large inventories of legacy Hg may be the dominant pathway driving present Hg uptake in Arctic marine and coastal areas. This explains the discrepancy between decreasing atmospheric Hg deposition in the Arctic in recent decades due to reduced global anthropogenic emissions, and the lack of response or increases in Hg-loads in many Arctic species, with implications for effectiveness evaluation of the Minamata Convention.
人为活动已导致北极地区出现大规模汞污染，汞含量达到有毒水平，但对汞源和迁移途径的了解却很少。在此，我们展示了在格陵兰岛各地采集的泥炭和关键水生捕食性物种中的汞稳定同位素数据。我们观察到明显的区域差异，受不同洋流影响，格陵兰中西部的总汞含量显著低于东北部，而汞同位素分馏值（δHg）则更高。虽然汞同位素非质量分馏值（ΔHg）表明大气汞沉积主要以零价汞（Hg(0)）的形式发生（60%-97%），但ΔHg显示特别是在淡水生境中存在显著的光化学脱甲基作用。我们发现肌肉组织中的δHg会随着与内部代谢转化相关的营养级升高而增加。最后，我们观察到在过去40年里，几种物种/地点的总汞和δHg显著增加，这表明人为汞源增加和/或环境过程发生了变化。这些发现表明，携带大量遗留汞的洋流可能是驱动北极海洋和沿海地区当前汞吸收的主要途径。这解释了近几十年来由于全球人为排放减少，北极地区大气汞沉积下降，而许多北极物种的汞负荷却没有响应或增加的矛盾现象，这对《水俣公约》的有效性评估具有重要意义。
