Fróðskaparrit - 01.07.2004, Blaðsíða 114

112
MERCURY IN THE FAROEISLANDS — A REVIEW OF AVAILABLE DATA
mercury concentration were in the range
1,5-2,0 mg/kg, in 16%, a mercury concen-
tration in the range 1,0-1,5 mg/kg was
found, and in 25,6 % the mercury concen-
tration was below 1 mg/kg, and thus within
the present day “edible” range as defmed
for instance by the directives of the Euro-
pean Union.
Squid
Analyses of squid (Loligo forbesi, n =14)
of mantle length between 21 and 42 cm
(mean =28,2 cm) in 1987 gave an overall
mercury mean concentration of 0,02 mg/kg
(Bloch etal., 1987).
Squid (Todarodes sagittatus) and Gona-
tus sp. samples from 1999 and 2000 were
analysed for mercury and cadmium as well
as persistent organic pollutant in a study of
pollutants in fulmars and their possible
prey (Dam et al., 2001). The mantle mer-
cury concentration in the Todarodes s. sam-
ples (n= 21) from the Faroe shelf area were
in the range 0,01 to 0,12 mg/kg, with dry
weight in the range 20-23%, in individuals
of mantle length between 19 and 40 cm
(mean 25 cm). In two smaller Todarodes s.
individuals (mantle length 10 and 15 cm)
samples in 2000 also from the shelf area,
the mantle mercury concentration was
0,034 and 0,030 mg/kg respectively. In a
batch of Gonatus sp. (n=50) samples taken
in 2000 at 68 N, 00 E, the whole animal
mercury concentration was not detected at
0,1 mg/kg dw.
Todarodes s. (n= 10) from Falkland wa-
ters in 1999 and mantle length in the range
18-25 cm were analysed as well, and the
mantle mercury concentration was found to
be 0,01 mg/kg (unpubl. results) and thus
highly comparable to the Faroese waters
samples. The most peculiar results of the
studies were the cadmium concentrations,
which appeared to be very variable in the
range 0,02 to 0,74 mg/kg. A larger selec-
tion of cephalopods (Todarodes s., Loligo f.
and Eledone cirrhosa) from Faroese waters
were analysed for cadmium in a study
where the aim was to elucidate the vectors
for the high marine mammal cadmium con-
centrations often encountered (Bustamante
et al., 1998). In this study, the cadmium
concentrations found were 0,46 mg/kg in
Loligo f, 3,46 mg/kg in Todarodes s. and
9,06 mg/kg in Eledone c. and thus increas-
ing still the range of cephalopod cadmium
concentrations.
Seabirds
Feathers
Birds’ feathers may be used in retrospec-
tive mercury analyses and such samples are
often available in museum collections and
can thus provide valuable data of compar-
isons to the present day mercury load in the
same bird species (Somer 1981; Appelquist
et al., 1985)
The mercury data which describe the
oldest samples of seabirds from the Faroe
Islands are those of feathers from Common
guillemot (Uria aalge) and Black guillemot
(Cepphus grylle) as Appelquist et al., 1985
analysed museum specimens in search of a
time tend in mercury in Guillemot sp. in the
Baltic as well as in the North-east Atlantic
area. The authors were able to describe an
increasing trend in mercury levels in the
Baltic as well as in the Faroes, where the