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

Fate of Mercury in the Arctic 13
Implied 3.1.3 A method must be developed to reliably and reproducibly analyse very non-
homogeneous sediment such as peat for Hg content.
Implied 3.3. Arctic peat must be compared with traditionally studied raised bog, peat profiles.
Implied 3.3.1 Arctic peat must be dated with high enough time resolution for comparison with
raised bog profiles. The traditional method of dating highly mineral peat cores such as Arctic peat,
i.e. 210 Pb chronologic modelling is sufficiently accurate for Arctic peat studies alone, but not
accurate enough for dating raised bog profiles. A direct dating method must therefore be developed
to allow comparison in the geochemically important upper layers of the peat profiles at each site.
Implied 3.3.2 Techniques must be developed for safe, effective and efficient sampling of peat in
the Arctic.
1.2 Summary of results
Bearing in mind the specified questions and implied tasks as noted, the main findings of my
Ph.D. work are as follows. Papers referred to are included in Appendix C.
Gaseous mercury is oxidized in the Arctic troposphere at polar sunrise. The resulting divalent
mercury product species, HgXY, suggested as HgBr2 and/or HgBrOH, is deposited to the
snow pack. The evasion of HgXY is also observed.
The micrometeorological technique conditional sampling or “relaxed eddy accumulation”,
REA, was developed for measurement of the flux of the operationally defined inorganic divalent
gaseous mercury compounds HgXY, reactive gaseous mercury, in the Arctic (paper 1, Goodsite et
al., submitted).
The first measurements and quantification of HgXY surface flux and depositional velocity to
the snow pack during polar sunrise was made, and an initial reaction mechanism suggested (paper
2, Lindberg et al., 2002).