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

Fate of Mercury in the Arctic 6
accumulation rates have since declined with the value for 1995, 14 µg m -2 yr -1 comparable to those
values published in 1995 from the Danish Eulerian Hemispheric Model (Christensen et al., 2002,
Skov et al., 2003, Appendix C), of 12 µg m -2 yr -1 for southern Greenland.
In Denmark, the greatest rate of atmospheric Hg accumulation is found in 1953, 184 µg m -2 yr -
1 , comparable to that of Greenland with the flux going into sharp decline, with an accumulation rate
for 1994 as 14 µg m -2 yr -1 . This compares well with the modelled rate of 18 µg m -2 yr -1 for all of
Denmark. On the Faroe Islands, the maximum mercury concentration was 498 ng g -1 . Dated to be
in 1954 +/-2, with a 210 Pb constant rate of supply dating model, in good agreement with historical
maximums in 1953 in S. Greenland and Denmark. Depositional maximum was in 1985, 34.3 µg m -2
yr -1 , with the 1995 value of 18 µg m -2 yr -1 , comparing with Denmark and the modelled value of
approximately 10 µg m -2 yr -1 . The present day value of approximately 10 µg m -2 yr -1 compares well
with recently reported measurements of 7 µg m -2 yr -1 (Daugaard, 2003). Long-term accumulation
rate of mercury in this core was 0.95 ± 0.36 µg m -2 yr -1 for the period of 4200 B.C. to AD 833; n =
61, in agreement with the Danish and South Greenland peat cores, peat cores from Switzerland and
what is known about the global mercury cycle, and what would be expected in a remote area. The
Hg concentrations in the Faroe Islands are higher than those found in cores from other sites, but the
net Hg accumulation rates are comparable.
The depositional records in the peat are in good agreement with what would be predicted:
lower depositional rates at sites further North from European industries; and in agreement with
previous atmospheric measurements that showed that total gaseous mercury in Europe reached an
average annual maximum in the late 1980’s and have been falling since 1990 decreasing globally
by 22% from 1990 - 1994 (Slemr et al., 1995 and references therein). The results are discussed
with respect to the available literature and their potential implication for our understanding of the
global mercury cycle.