FATE OF MERCURY IN THE ARCTIC Michael Evan ... - COGCI

Fate of Mercury in the Arctic 116
In the high Arctic, due to the slow sedimentation of environmental archives, one of the ways to
see any tendency is to continue long-term environmental monitoring studies.
The background levels of mercury in the peat core are very consistent with what is understood
of the global cycling of mercury and its long atmospheric residence time. The cores show some
variation due to natural process, geogenic or climatic, and the reasons for these pre industrial
variations should be more closely examined in the future, since it may provide insight into the
question of how the expected warming climate will affect mercury deposition to the Arctic in the
future, having observed how it was affected in the past, though without human effects.
Even though mercury deposition may be declining, there are recently still negative effects
observed such as attenuated growth of breast fed children exposed to increased concentrations of
methyl mercury and other contaminants such as polychlorinated biphenyls (PCBs) (Grandjean et al.,
2003).
Munthe et al., (in press) summarized that the global nature of mercury transport affects not only
local areas, but regions such as Europe. Therefore control measures in Europe will not reduce
atmospheric deposition to acceptable levels in Northern Europe. They state that “there is a need to
assess the hemispherical and global background levels and to what extent these are impacted by
anthropogenic emission.” This work shows that by coming peat archives with stable lead isotope
measurements and high time resolution dating, that future assessments may be made using this type
of environmental archive.
Gårdfelt et al., (in press) measured and modeled that 66 tonnes of mercury are released to the
atmosphere from the Mediterranean Sea during the summer. They corroborate measurements in the
Atlantic showing that this type of evasion is not confined to the temperate regions. Oceanic evasion
should therefore be looked at in the Arctic region as a possible source of Hg to the Arctic.