Fróðskaparrit - 01.07.2004, Qupperneq 125

KYKSILVUR í FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
123
Fig. 17 Mercury in white sided dolphin
musclefrom Klaksvík 1997. Tlie regression
line based on the female results is shown
(Adaptedfrom Dam, 2001).
this species. However, during the Klaksvík,
21st August 1997 hunt, involving 150
white-sided dolphins, samples were taken
for analyses. From a total of 28 individuals
samples of muscle and blubber were taken
and analysed for mercury and persistent or-
ganic pollutants respectively (Dam, 2001).
The overall mean muscle mercury (Fig. 17)
concentration was 0,94 mg/kg and thus
lower than in an average pilot whale pod.
The representativity of this sample, which
consisted of 12 adult males, 8 adult females
and 8 juveniles, of which only one male, is
uncertain though. From the same school,
kidney tissues were taken for cadmium and
mercury analyses. The kidney mercury
concentration were in the range 0,1 to 2,5
mg/kg, with the lowest concentrations in
individuals younger than 1 year and the
highest in a 10 year old male. The kidney
cadmium concentration, which occurred in
calcium-cadmium-phosphate in a Ca:Cd
ratio of 10, was not detectable in the juve-
niles (at 0,1 mg/kg) and was 31,1 mg/kg in
the same 10 yrs old male (Gallien et al.,
2001). In a study involving a few white-
sided dolphins from the Irish coast, con-
centrations of mercury in muscle (n=3)
were 2,7 mg/kg dw and in kidney (n=l) the
concentration was 7,8 mg/kg dw (Das et
al., 2003). Assuming a dry weight of 30%,
these findings would compare to approx.
0,8 mg/kg and 2,3 mg/kg in muscle and
kidney respectively, which is in the range
found in the studies on the Klaksvík 1997
samples. In a single white-sided dolphin
adult male found stranded on the Belgian
coast in 1999, kidney cadmium and mer-
cury concentrations at 2 mg/kg and 12
mg/kg were found, thus also within this
same range (Das et al., 2002).
Grey seal
Grey seal, Halichoerus grypus, is abundant
in the Faroe Islands, but there are few data
available on pollutants concentrations in
this species.
In connection with a Ms.Sc. study in
1993-1995 on the Faroese grey seal diet
(Mikkelsen, 1998) samples were also taken
to be deposited in the Environmental Spec-
imen Bank (http://www.hfs.fo/enviromen-
tal_specimen.htm) for future analyses of
pollutant concentrations as well as for oth-
er purposes. A subset of samples from 45
individuals were analysed for mercury,