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

Fate of Mercury in the Arctic 63
4. Results and Discussion
Laboratory experiments
The laboratory experiments were carried out in the lab of Dr. Steven Lindberg, in the
Environmental Sciences Division, Oak Ridge National Laboratory, USA. The building has a
common ventilation system, turned off after work hours to save energy, and many scientists in the
building have used mercuric chloride for their experiments. Therefore RGM levels are
approximately twice as high as what is expected for ambient, though comparable with
measurements at Station Nord, just prior to an AMDE. None of the denuders were heated in the
laboratory; the denuders were at room temperature, approximately 23 0 C.
In Figure 6., page 64, the annular denuders were hung in parallel, in the laboratory; and allowed to
sample for 1 to 2 hours during the day and for 16 hours during the night and into the weekend.
Concentration levels may be slightly underestimated since the denuders were not heated for the
experiments. The figure shows that denuders that are 1 year old, X1 and X2 appear to be
functioning just as well as denuders that are new: numbers 1-5. Reproducibility is within 10%,
except for the first experiment. Denuders were cleaned and recoated after each use. The results
show that under laboratory conditions, where HgCl2 is expected to be the dominating RGM species,
that non-heated KCl coated denuders are able to collect a significant amount of RGM at ambient
temperature in a reproducible manner.