Fróðskaparrit - 01.07.2004, Side 104

102
MERCURY IN THE FAROEISLANDS — A REVIEW OF AVAILABLE DATA
Fig. 5 Sampling areas in the Faroese fjords are shown
(Gregersen et al., 2000).
On the banks
In Table 8 results of heavy metal analyses
on marine sediments are given. The sedi-
ment samples have been taken from the
banks Skeivabanka, Sandoyarbanka and
Føroyabanka, where the latter is located
west of the Faroe Plateau. Analyses of
these sediments show a mercury concentra-
tion of between 4 and 10 ug/kg. The sedi-
ments from Skeivabanka were also analy-
sed for PAH, PCB and some pesticides
(Magnusson et al., 1996; Stange et al.,
1996).
As part of the AMAP project four repli-
cate sediments cores collected on Sando-
yarbanka were dated by radiological analy-
Fig. 6 Age (in years) and mercury concentration
(ag/kg dw) profdefor seabed-sediments from
Sandoyarbanka (Olsen et ai, 2003)
ses and analysed for mercury concentration
in segments of 1 cm (Olsen et al., 2003).
The mercury concentration in the upper-
most segment is given in Table 8. In Fig. 6
the mercury concentrations in all segments
of the four cores are given as a function of
the age determined for the segments. Fig. 6
shows that there are some variation in mer-
cury concentrations in the four cores espe-
cially in the top-most sediment layers. De-
spite this variation it is clear that the mer-
cury concentration in the sediments have
increased from about 5 pg/kg 100-120
years ago, to about the double 30-40 years
ago, after which it seems to decline again
during the last 20-25 years.
Comparing the results of the Sando-
yarbanka sediments to those in the fjords
may be done by comparing results in Table