Fróðskaparrit - 01.07.2004, Page 92

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MERCURY IN THE FAROEISLANDS — A REVIEW OF AVAILABLE DATA
Starvsstovan in precipitation collected
three times yearly since 1996 (Dam 1998)
at Norðuri á Fossum. The locality Norðuri
á Fossum is used as the Faroese reference
station to the UN/ECE Long-range trans-
boundary air pollution programme on Inte-
grated Monitoring. At this site, regular
analyses of major ions in precipitation are
made and results are reported to the
UN/ECE Integrated monitoring data centre
at the Finnish Environmental Institute.
However, mercury in precipitation was
measured for the fírst time at the Faroe Is-
lands in 2002 as part of a Master of Science
program (Daugaard, 2003).
Deposition was collected at Elduvík,
Eiði, Saksun, Vestmanna and Kirkjubøur
for 6 periods each of 3 weeks duration cov-
ering the period June to October 2002. The
sum mercury deposition during the 6 week
period varied from 5,3 ng to 10,9 ng Hg. A
distinct negative correlation was found be-
tween the amount of deposition and the
concentration of mercury in deposition, in-
dicating that the washout of mercury from
the atmosphere were most intense during
the fírst mm of the rain-shower. (Daugaard,
2003).
The terrestrial and
freshwater environment
Peat and Soil
Peat core samples were collected in May
2000 from the two peat-bogs á Mýrunum in
Vestmanna and the Klovin bog in Vatns-
oyrar (Roos et al., 2001). The samples from
á Mýranar were analysed for mercury and
dated in order to study the changes in mer-
cury fluxes with time. The results (Shotyk
et al., 2003; 2004) indicated that the major
part of mercury in the peat has been trans-
ported through the atmosphere. Several
layers of ash in the peat cores were noticed
and these seemed to originate from Ice-
landic volcanoes. Although it was pre-
sumed that some volcanoes have had a cer-
tain influence on the mercury supply to
these samples, some very high values in the
peat for the time-period around 1950 could
not be explained by natural sources alone.
Besides mercury, high values of bromide
and chloride were found which showed the
impact of sea spray on the peat. Despite the
cutting of peat it appeared that the time pe-
riods were well preserved (Goodsite et al.
2002).
Shotyk et al. (2004) declared that the
measured mercury values were higher than
those found in other Nordic countries and
that the results indicated that the natural
background flux of mercury to the Faroes
was always elevated, compared to conti-
nental bogs. Superimposed on these elevat-
ed natural fluxes, however, they found a
much greater Hg flux in samples from the
last two centuries. The large total mercury
peak (498 ng Hg/g dw) at á Mýranar were
found in depths between 5 cm and 6 cm,
and was higher than what could reasonably
be explained by geo-chemical mechanisms
or natural input.
Data are available on a number of metals
and minerals in soil and basalt (Rasmussen
and Noe-Nygaard, 1969; Joensen and
Vestergaard 1995; Mikkelsen et al., 2002)
but few data are available on mercury,
(Table 1).