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

Fate of Mercury in the Arctic 57
3.7 Peat analysis
The author was the manager and one of the principle investigators for the international and
interdisciplinary peat project “long term records of atmospheric deposition of Hg, Pb, Cd and POPs
in the Arctic” with Prof. William Shotyk as the chief scientist.
Peat localities were chosen, primarily based on pre-existing geological or botanical studies
for the area, so that any trace metal knowledge gained would be complementary to previous studies,
and as the data from previous studies would be supplemental to the trace metal studies.
Once reconnoitred, the sites judged to be the best, i.e., apparently topographically and
hydrologically isolated, deep, non-disturbed, ombrotrophic type mosses, were sampled, typically on
the lawn of the peat hummock, i.e., halfway between the hummock and hollow. Peat monoliths
were taken with a titanium Wardenaar corer (Wardenaar, 1987).
In the high Arctic, due to the need for automated coring through the permafrost, samples
were cored from the top of the hummock. Hollow peat was sampled as well, since it represents
modern growth. Frozen arctic peat does not allow readily sampling, so an automated peat sampler,
was developed for this work. The version taken to Bathurst improved, by coating with teflon, and
redesigning the cutting blades and top cap of the bore, prior to being taken to Nordvestø. Details of
this sampler and its use are given in Noernberg et al, 2003, Appendix C.
After sampling in the field peat was packaged and frozen for and during transport, where it
was then processed in the laboratory at either University of Berne, Geological institute, or in the
case of high Arctic peat, at the University of Heidelberg Institute for Environmental Geochemistry.
The cores to be analysed for trace elements were sliced while still frozen, every 1 cm and sub
sampled.
The "zero" depth of the monolith was taken to represent the interface between the living plant
material at the top, and the underlying dead plant matter, peat. For high Arctic peat, the coring