Fróðskaparrit - 01.07.2004, Síða 107

KYKSILVUR í FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
105
d.w. (%) A1 Cd Cu Hg pg/kg dw Pb Li
F platau shelf/slope, 300-500 m 73 0,09 15,9 2 6,84 6,43
depth, mean of 20 stations
std.dev 4,1 0,021 5,3 0 1,85 1,21
Min. 67,4 0,067 7,6 <1 3,43 4,64
Max. 78,1 0,148 28,7 3 10,1 8,13
F-S Channel 800-1200 m 34100 0,031 7,9 8 5,7 13,2
depth, mean of 16 stations
std.dev 548 0,007 1,5 3 0,8 1,3
Min. 0,024 5,3 3 4,6
Max. 0,042 9,6 15 6,4
Table 9 Concentrations of metals (in mg/kg d.w.) in sediments from the south-east slope ofthe Faroe shelfin
1999 and in tlie Faroe-Shetland Channel in 2001 (Grøsvik et al., 2000; Mannvik et al., 2002).
ses and chemical analyses of the topmost
centimetres of the sediments (Mannvik et
al„ 2002).
It is of interest to note that in the Faroe-
Shetland Channel, the sedimentation rate
was analysed in four samples (station
1,2,11 and 20 in Fig. 7) and the very low
sedimentation rates found indicated that
this area is non-depositional, meaning that
particulates present in the deeper waters
don’t settle at the seabed but are transport-
ed along in a southward bound current.
The littoral
The earliest analyses of heavy metals (Pb,
Cd, Cu, Ni, Zn, Hg and Fe) in kelp Lami-
naria sp. and barnacle Balanus sp. were
done on material sampled in Skálafjord at
the coast just off the stations St. 1, St.2, St.3
(SK09, Fig. 5) and St.4 (SK05) (Heilsu-
frøðiliga Starvsstovan, 1992). The stations
1 and 2 are in the bottom of the fjord and
station 4 at the sill near the outer end. In the
1992 study, mercury was not detected (at
0,03 mg/kg dw) in Laminaria sp. nor in
Balanus sp. In 1996-97 samples of kelp
Laminaria hyperborea, and limpets Patella
vulgata, sampled in Kirkjubøur, were
analysed for heavy metals (Cd, Cu, Hg and
Pb) and persistent organic pollutants and
PAH, as part of a project dedicated to Inte-
grated Monitoring in the coastal zone
(Dam, 2000). In the project, seasonal varia-
tions in food-choice, lipid content, pollu-
tant levels etc. as well as food-web interac-
tions on pollutant levels were studied. The
analyses were done on the lamina of kelp
and on soft parts of limpets, but mercury
could not be detected at 0,02 mg/kg dw and
0,02 mg/kg ww in kelp and limpets respec-
tively. Limpets in the size range of approx.
4,5 to 5,5 cm diameter shell base were also
sampled at Velbastaður, Gamlarætt, Tors-
havn, Kaldbak, Veðranes and Trøllavík. In
the two first mentioned sites, mercury
could not be detected (at 0,02 mg/kg),
whereas at the two last mentioned locations
mercury was 0,02 mg/kg and in Torshavn
and Kaldbak 0,03 mg/kg (Dam, 2000). In
the same period, heavy metal analyses were