Fróðskaparrit - 01.07.2004, Síða 96

94
MERCURY IN THE FAROE ISLANDS — A REVIEW OF AVAILABLE DATA
of air-borne mercury in the Faroes above
the level found in the Scandinavian coun-
tries.
Freshwater lakes
Since the late nineties trout (Salmo trulta)
and Artic char (Salvelinus alpinus) from se-
lected waters have been analysed for mer-
cury (Table 3). Some of these waters are
dams constructed for hydroelectric purpos-
es, as Eiðisvatn, which was dammed in re-
cent years and the oldest dam, á Mýranar,
which was dammed in 1960/1961 (Jacob-
sen, 2003) closely followed by Heygardals-
vatn in the same waterway during 1961/
1962 (Hermansen, 1999). The lakes Leyna-
vatn, Leitisvatn and Fjallavatn are natural
lakes, and the former is the only one in
which Arctic char is naturally occurring. To
the á Mýranar dam, Arctic char has been set
out, and from this it has found its way down
to the Heygardalsvatn after the emptying of
the Heygardalsvatn dam in 1992 due to a
furunculosis outbreak (Niðristovu, 1998).
The smaller (and younger) trout were
found to contain smaller amounts of mer-
Species Location Year Number of samples Average age (year) / weight (g) Hg, mg/kg ww Source
Trout Fjallavatni 1997 19 4+/ 109 0,23 Larsen and Dam,
1999
Fjallavatni 1997 9 5+ / 203 0,36
Leitisvatni 1997 16 4+ / 123 0,30
Leitisvatni 1997 7 5+/201 0,35
Eiðisvatni 2000 3 2+ 0,08 Hentze, 2000
Eiðisvatni 2000 3 5+ 0,11
median 0,26
Arctic char Heygardalsvatni 1998 15 8,0/3221 0,07 Dam, 1999
Leynavatni 1998 15 7,8/131 0,18
Mýrarnar 2000 5 7,2 / 558 0,14 Olsen et al., 2001
Mýramar 2000 10 8,4/616 0,17
Mýrarnar 2000 10 8,4 / 686 0,18
Mýramar * 2001 (n=8) -/384 0,16 Olsen et al., 2001
Mýramar * 2001 (n=8) -/543 0,21
Mýrarnar * 2001 (n=8) -/494 0,26
Mýrarnar * 2001 (n=8) -/554 0,23
Mýrarnar * 2001 (n=8) -/549 0,25
median 0,18
* Analysed in pooled samples each combining 8 individuals.
Table 3 Mercury concentrations in trout and Arctic char.
(Adapted from Mikkelsen et al., 2002)