No evidence for large mercury release from the Greenland Ice Sheet: recent conclusions on global mercury budget invalidated.

Christian Juncher Jørgensen, Jens Søndergaard, Martin Mørk Larsen, Kristian Kjellerup Kjeldsen, Diogo Rosa, Sarah Elise Sapper, Lars Eric Heimbürger-Boavida, Stephen G. Kohler, Feiyue Wang, Zhiyuan Gao, Debbie Armstrong, Christian Nyrop Albers

Publikation: Bidrag til bog/rapport/konferenceproceedingsAbstract i proceedingspeer review

Resumé

Local glaciers and ice caps in the Northern Hemisphere and the Greenland Ice Sheet (GrIS) have recently been suggested to be important parts of the Arctic mercury (Hg) budget. Based on icecore data, the recently estimated total glacial Hg pool is approximately 2,400 tons, approximately 97% of which is in Greenland. With Hg concentrations in pre-industrial ice being significantly lower than in ice formed during the 19th and 20th centuries, the dominating source of glacial Hg and input to the Arctic Hg budget is ascribed to long-range transport of anthropogenic Hg emissions.
Alarming concentrations of Hg in meltwater from the western margin of the GrIS were recently reported. With Hg concentrations reported as being 100 - 1000 times higher than what is known for other freshwater systems of Greenland and a postulated increase in Hg export to downstream environment following climate warming and asserted global importance of Hg fluxes from the GrIS, these extraordinary concentrations and conclusions calls for independent verification.
In our current study, we expand the sampling of subglacial meltwater from 21 representative
outlets at GrIS in 2021 and 2022 to get a better scientific basis for conclusions on the magnitude of glacial Hg sources in Greenland. Results from our study consistently show that both total and dissolved Hg concentrations in glacial meltwater over space and time are very low (generally <10 pM) and that an extremely elevated Hg concentration range (up to 4000 pM recently reported) cannot be reproduced.
In contrast to what was previously reported, we find that meltwater from below the GrIS is very low in Hg; has minor implications for the global Hg budget and pose only a very limited risk for local communities and the natural environment of Greenland.
OriginalsprogEngelsk
TitelProceedings of the European Geosciences Union, General Assembly
UdgivelsesstedVienna
ForlagEuropean Geosciences Union
StatusUdgivet - 2024
BegivenhedEGU Gentral Assembly 2024 - Vienna, Østrig
Varighed: 14 apr. 202419 apr. 2024
https://www.egu24.eu/

Konference

KonferenceEGU Gentral Assembly 2024
Land/OmrådeØstrig
ByVienna
Periode14/04/2419/04/24
Internetadresse

Programområde

  • Programområde 4: Mineralske råstoffer

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