Fróðskaparrit - 01.07.2004, Blaðsíða 129

KYKSILVUR f FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
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The long-range transported mercury thus
outweighs many times the import that oc-
curs via pilot-whale catches, even though
the mercury in meat may lead to locally el-
evated concentrations of more concern than
the air-borne one.
In the marine environment, the mercury
concentrations in marine mammals, and in
particular in long-finned pilot whales are
elevated compared to the Ievel off New-
foundland (Muir et al., 1988) where the
mean muscle mercury concentration in two
groups of stranded pilot whales were 0,9
mg/kg (n=15) and 0,8 mg/kg (n=29) with a
range of individual age in the last pod of 1-
17 yrs.
The pilot whale and white-sided dol-
phins utilize large sea areas and it is thus
not correct to use these species to describe
the Faroese environment. For this, station-
ary species must be used, and widely used
such indicator species for the coastal area is
the blue mussel.
Overall, the mercury concentrations in
blue mussel sampled from sites around the
Faroese coast are higher than the OSPAR
background/reference level (QSR, 2000).
Whether the sources for these are local
ones, like sewage outlets, fish farms of land
based industry, is not known. The bad news
is however, that a certain anthropogenic im-
pact is likely inherent in every blue mussel
sample from the Faroe Islands because the
mussel do only live in the sheltered fjord
areas which receive inflow of nutrients
from anthropogenic activity.
Mercury in fjord sediments have been
analysed in 1997 and 2000, and in one
fjord, Skálafjord, also in 1992. It appears
that mercury concentrations in Skálafjord
have been elevated above what may be de-
fined as the natural level, but that the mer-
cury concentration in this fjord is decreas-
ing. Comparisons between mercury con-
centrations in sediments from the banks to
those taken in the fjords (Skálafjord ex-
cluded) when expressed on a organic con-
tent basis, indicate that the relative levels of
mercury are similar in the fjords and on the
banks.
Conclusion
The available mercury data for the Faroese
environment do indicate that there are ele-
vated mercury concentration in certain ma-
trices, among them soil, marine mammals
and in certain instances also marine and
freshwater fish. There are however, no indi-
cation that the transport of mercury to the
Faroe Islands is elevated above what could
be expected from comparisons to the other
Nordic countries except of course from the
import carried by pilot whales which result
in an elevated mercury level in the Faroese
population as is also seen in other commu-
nities utilizing marine mammals as a food
source (AMAP 1998; 2002; Weihe et aL,
2003). Still, the elevated mercury levels in
certain matrices in the Faroese environment
warrant a closer study of the mechanism
behind the apparent concentration of de-
posited mercury. At present, studies are on-
going on some of these matrices, with par-
ticular emphasis to examine the geographi-
cal extent of the elevated levels and possi-
bly trace sources, but these are not the
needed in-depth analyses with a potential to
explain mechanisms.