Measurements of atmospheric mercury species during Arctic springtime

Updated 2003-03-04

The major goal of the process study between April 15 and May 15, 2003 is to obtain quantified information on reaction path-ways, products and net deposition of mercury during Arctic sunrise.

Comments and additional information:

Mercury and many of its compounds behave exceptionally in the environment due to their volatility and capability for methylation, in contrast with most of the other heavy metals. Long-range atmospheric transport of mercury, its transformation to more toxic methylmercury compounds, the ability to photochemical reactions and their bioaccumulation in the aquatic foodchain have made it to a subject of global research activities even in polar regions. At the beginning of polar spring the phenomenon of mercury depletion events (MDEs) has been discovered in the high Canadian Arctic a few years ago. Simultaneously with ground level ozone concentrations, mercury concentrations drop down to levels below the background values. As a chemical element mercury cannot simply decomposed (like ozone for example) but can be converted into species that are removed from the atmosphere by deposition processes. In 2001, researchers of GKSS Research Centre, Alfred Wegener Institute and the University of Jena have completed the first annual time series of atmospheric mercury concentration measurements at the German Neumayer Station and have reported that MDEs do also occur in the Antarctic. It can be assumed that as a result of a complex series of atmospheric reactions enhanced deposition fluxes of mercury into the polar coastal ecosystem occurs during springtime. This enhanced deposition flux can be an important link for the understanding of mercury contamination and bioaccumulation in the Arctic ecosystems. According to the proposed mechanism, heterogeneous reactions occurring at the interface of sea salt aerosols lead to the oxidation of elemental mercury in the troposphere. Sea salt aerosols contain high concentrations of chloride or bromide ions, which can react to form gaseous halogen radicals in the presence of light. The radicals react photochemically with ozone, forming halogen oxides (BrO or ClO), which, in turn, oxidize elemental mercury to Hg(II). Either way, reactive gaseous mercury (RGM) is formed, which researchers believe could be HgO, HgBr2, and / or HgCl2. Recent investigations support the theory that reactive bromine, which destroys ozone and can oxidize elemental mercury in a subsequent reaction, is released from sea salt surfaces, which are provided either by sea ice surfaces or by uptake of sea salt aerosols. BrO vertical column densities over the Antarctic, obtained from the satellite-based GOME (Global Ozone Monitoring Experiment) instrument, have revealed, that most of the sea ice where enhanced BrO concentrations are found is located north of Neumayer station at lower latitudes and can cover the ocean up to 55oS. Therefore, the depletion of atmospheric mercury during Antarctic springtime must be seen as a phenomenon which is not restricted to the Antarctic continent but also to the surrounding ocean.

Time frame

Status
Planned
Project time span
2003 - 2003
Data collection
2003 - 2003
Data processing
not specified
Data reporting
not specified

Contact information

Contact person
Dr. Ralf Ebinghaus
Address
GKSS Forschungszentrum Geesthacht GmbH Institut für Küstenforschung / Physikalische und Chemische Analytik, Max-Planck-Str.1 D-21502 Geesthacht
Phone
+49-4152 87 2354
Fax
+49-4152 87 2332
Email
ed.sskg@suahgnibe.flar
Other project contacts
Kontaktperson: Hans Herbert Kock Tel.: +49-4152 87 2368 Fax: +49-4152 87 2366 E-mail: hans.kock@gkss.de

Parameters and Media

Parameter groups measured/observed/modelled
Other metals/elements
Media sampled/studied/modelled
Air/aerosol

Geography

Regions studied
Arctic, Circumpolar
Koldewey Station, Ny-Ålesund/Spitsbergen
Svalbard
Zeppelin mountain Atmospheric Research Station
Other areas
Kongsfjord, West Spitsbergen

Data availability

Samples/specimens archived in specimen banks?
No

Methods & Procedures

Procedures and methodology used for, e.g., sampling and sample storage, sample pretreatment, extraction and analysis, including which laboratories are involved, references to methods employed, etc.

Simultaneous measurements of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particulate-phase mercury (PPM) will be carried out between April 15 and May 15, 2003. GEM and RGM will be measured on-line with a time resolution of 15 minutes or 1 hour respectively. Changes in the relative concentration ratio of these species from the pre-depletion towards the depletion period will provide a better insight in the reaction pathways and the resulting products. Similar measurements will be carried out by other groups at the Zeppelin Station. Comparison of the results will give information on the role of the marine boundary layer on the atmospheric chemistry of mercury, since Zeppelin Station is located about 450 m a.s.l. , whereas Koldewey is almost at sea level and also closer to the coast line.

Additional Information

Is this a bi- AND multi-lateral project (i.e. a project involving cooperation between different countries)?
Yes
Other institutes involved in the project

The intended research work is part of an international process study aimed at a better understanding of the recently discovered phenomenon of mercury depletion events (MDEs) in polar environments during springtime. The planned process study consists of a number of simultaneous measurements of atmospheric mercury and related parameters by the applicant at Koldewey, and at the Zeppelin-Station, the French and Italian station at Ny Alesund. Participants of the Process Study will probably be - Norwegian Institute for Air Research (NILU) as the coordinating institute - Swedish Environmental Research Institute, IVL - Chalmers University, Göteborg - Institute for Atmospheric Pollution, Rende, Italy (IIA-CNR) - Institute de Glaciology, Grenoble, France - Environment Canada, Meteorological Service of Canada (MSC) - Oak Ridge National Laboratory, (ORNL), USA - National Oceanic and Atmospheric Administration (NOAA), USA It should be noted, that the list of participating laboratories is presently only a tentative one.

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