Unequal anthropogenic enrichment of mercury in Earth’s Northern and Southern Hemispheres

Li, Chuxian; Sonke, Jeroen E.; Le Roux, Gaël; Piotrowska, Natalia; Van der Putten, Nathalie; Roberts, Stephen J. ORCID: https://orcid.org/0000-0003-3407-9127; Daley, Tim; Rice, Emma; Gehrels, Roland; Enrico, Maxime; Mauquoy, Dmitri; Roland, Thomas P.; De Vleeschouwer, François. 2020 Unequal anthropogenic enrichment of mercury in Earth’s Northern and Southern Hemispheres. ACS Earth and Space Chemistry, 4 (11). 2073-2081. https://doi.org/10.1021/acsearthspacechem.0c00220

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Official URL: https://pubs.acs.org/doi/10.1021/acsearthspacechem...

Abstract/Summary

Remote Northern Hemisphere (NH) and Southern Hemisphere (SH) lake sediment and peat records of mercury (Hg) deposition have shown a ×3 to ×5 Hg enrichment since pre-industrial times (<1880 AD), leading to the perception that global atmospheric Hg enrichment is moderate and uniform across the hemispheres. Anthropogenic Hg emissions in the NH are, however, approximately 4 times higher than those in the SH. Here, we reconstruct atmospheric Hg deposition in four remote SH peatlands and review sediment and peat Hg records from both hemispheres. We observe a ×4 all-time enrichment in SH Hg deposition from pre-anthropogenic (<1450 AD) to the late 20th-century periods, which is lower than the large ×16 all-time enrichment in NH Hg deposition. We attribute this difference to lower anthropogenic Hg emissions in the SH, and higher natural atmospheric SH Hg concentrations, supported by ×2 higher natural background Hg accumulation in SH peat records. We suggest that the higher SH natural atmospheric Hg deposition reflects the SH land–ocean distribution, and is driven by important SH marine Hg emissions. Our findings indicate that atmospheric Hg background levels and anthropogenic enrichment in both hemispheres are different and should be taken into account in international Hg assessments and environmental policy.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1021/acsearthspacechem.0c00220
ISSN:	2472-3452
Additional Keywords:	mercury, enrichment, peat, sediment, archive, hemisphere deposition
Date made live:	20 Nov 2020 06:26 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/528991

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1021/acsearthspacechem.0c00220

ISSN:

2472-3452

Additional Keywords:

mercury, enrichment, peat, sediment, archive, hemisphere deposition

Date made live:

20 Nov 2020 06:26 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/528991