Fróðskaparrit - 01.07.2004, Side 102

100
MERCURY IN THE FAROEISLANDS — A REVIEW OF AVAILABLE DATA
Fig. 4 Mercury concen-
trations in sediments are
shown as afunction of organ-
ic matter (% loss on ignition
at 550 °C) in the 1997 fjord
sediment samples. A regres-
sion curve based on the Fun-
ningsfjord data is shown.
(Adapted from Mikkelsen et
al„ 2002).
In recent years, quite a number of sedi-
ment samples have been analysed as part of
the environmental monitoring done as part
fulfilment of the permit conditions by li-
cense holders on aquaculture pens. Apart
from analyses of nutrients like nitrogen and
phosphate this monitoring includes analy-
ses for the metals Zn, Cu, Cr, Ni, Hg, Cd
and Pb (Mikkelsen et al., 2002). Results
from the reference stations of these analy-
ses are given in Table 7 along with those
from the same stations in 1992 and 1997.
The highest concentrations of mercury
were found in Skálafjord, with concentra-
Locations and year Pb Hg Cd Cu Zn Dry weight, % Organic carbon %* Source Depth
Skálafjørður, 1992 0.11 Heilsufrøði- 0-5 cm
(min. - max.) 15,0- 0,08- 0,14- 61,2- 44,4- 32,9- 6,4- liga starvs-
38,6 0,17 0,25 131,3 90,9 0,0 12,6 stovan, 1992
Tangafjørður, 1994 16,5 <0,04 0,221 21,2 78,2 Granmo, 1996 0-2 cm
Fjords 1997* m 0.04 0.15 92,4 61.7 61 Heilsufrøði- 0-2 cm
(min. - max.) 9,4- 65,4- 30- 3,3- liga starvs-
27,7 116 91 11,8 stovan
# Organic carbon in % dw or Loss on ignition in % dw.
nd = Depth of analysed sediment core not defined.
* Fjords in 1997 are: Skálafj., Tangafj., Funningsfj., Kaldbaksfj. and Sundalagið N.
Table 6 Heavy metals in sediments from Faroese fjords. Values are in mg/kg dw. Underlined values are
geometric means. (Adapted from Mikkelsen et al., 2002)