TOTAL MERCURY CONTENT IN INLAND SNOW AND THEIR IMPLICATIONS FOR MERCURY DYNAMICS IN ANTARCTICA

Abstract

The total mercury concentration (HgT) determined from surface snow and snow pit samples collected at Dome Fuji in East Antarctica provided new information on mercury dynamics in inland Antarctica. The HgT ranged between 0.20 and 10.8 pg g-1 and mean mercury sequestration rates were 1 - 3 pg cm-2 yr-1. Spatial and temporal profile of HgT and comparisons with other elements revealed that mercury behaves uniquely in the Antarctic interior. The seasonal variation in Hg sequestration was characterized by summertime maxima, even though the peaks were not always exactly in phase with sulfate or 18O. The summer HgT peaks may be related to the active photochemical dynamics of mercury. However, its impact on Hg sequestration is limited to a few pg g-1. We ascribe the interannual change in Hg sequestration to the variation in the atmospheric circulation over Antarctica, which regulates the meridional transport of aerosols containing oxidant precursors, continental dust, moisture and heat, each of which is thought to play a role in the mercury dynamics on the Antarctic Plateau.-1 and mean mercury sequestration rates were 1 - 3 pg cm-2 yr-1. Spatial and temporal profile of HgT and comparisons with other elements revealed that mercury behaves uniquely in the Antarctic interior. The seasonal variation in Hg sequestration was characterized by summertime maxima, even though the peaks were not always exactly in phase with sulfate or 18O. The summer HgT peaks may be related to the active photochemical dynamics of mercury. However, its impact on Hg sequestration is limited to a few pg g-1. We ascribe the interannual change in Hg sequestration to the variation in the atmospheric circulation over Antarctica, which regulates the meridional transport of aerosols containing oxidant precursors, continental dust, moisture and heat, each of which is thought to play a role in the mercury dynamics on the Antarctic Plateau.