In Arctic regions mercury is subjected to a unique savaging process known as Atmospheric Mercury Depletion Events, or AMDE’s. During these events chemical reactions involving low level ozone, light, frozen surfaces, and halogen radicals such as bromine act to convert the common un-reactive gaseous mercury to a highly reactive form. This reactive mercury species can then be easily deposited onto the snow, ice, or ocean surface. AMDE’s typically make their appearance at the beginning of polar sunrise in early February and continue until snow melt in mid June.

Mercury is known as a global pollutant due to its high toxicity, its ability to be transported over large distances, and its ability to biomagnify along the food chain. Average global concentrations of atmospheric mercury have remained fairly constant over the last 10 years, however despite this mercury levels in arctic mammals has been increasing. The aim of my study is to identify the intensity of these events, as well as determine their contribution to mercury loading in the marine environment. The circumpolar flaw lead system provides a unique of study in that the formed open water provides a major source for halogen radicals required which may intensify the AMDE’s leading to increased deposition, and in turn increased contamination. The open water also provides an area where the deposited mercury can directly enter the marine environment. With global warming, open water associated with these flaw leads may be increasing in size leading to increased deposition of mercury compared to previous years. I hope that this study will help shed new light on the mystery of increasing arctic mercury contamination.
Jeff.