In a report commissioned by the Norwegian Pollution Control Authority (SFT), the Norwegian Institute for Air Research (NILU) summarizes the results derived from three years of measuring atmospheric mercury at the Global Atmospheric Watch monitoring observatory operated at Zeppelin mountain near Ny-Ålesund on Svalbard.
Atmospheric conditions
Mercury is one of the most dangerous environmental toxins in the Arctic, but we know little about where this mercury comes from or how it is transported to the Arctic. It was previously believed that only small amounts of mercury from the atmosphere were deposited on the ground, but recent research shows that spring in the Arctic produces some very special chemical and physical conditions in the atmosphere.
Reactive mercury
These conditions, in which bromide or chloride from the ice-covered ocean acts as a catalyst and the sunlight provides energy, combine to convert less reactive mercury in the atmosphere into reactive mercury. This reactive mercury can come in both gaseous and particulate forms.
Mercury in snow
Reactive forms of mercury are deposited more quickly on the ground and are more readily absorbed by biological matter than is the case with less reactive mercury, and this in turn causes increased deposition. Measurements show that concentrations of mercury in the snow increase at this time of year.
Some of the mercury deposited in the snow is converted back to less reactive mercury and returns to the atmosphere, but a significant amount remains in its reactive form in the snow. The risk of exposure to mercury is thus increased considerably at a time of year when plants and animals are getting ready for the short summer season.
Automated measurement
This phenomenon was only discovered following the introduction of automated monitoring equipment. The Norwegian Institute for Air Research installed this kind of equipment at the new monitoring observatory at Zeppelin mountain in February 2000
Read more about:
For enquiries, please contact:
