Fróðskaparrit - 01.07.2004, Blaðsíða 94

92
MERCURY IN THE FAROE ISLANDS — A REVIEW OF AVAILABLE DATA
Fig. 2. Mercury versus manganese
concentrations in the soil profile segments
collected Norðuri á Fossum, are plotted
against each otlier. (Heilsufrøðiliga
Starvsstovan, unpubl.)
ganese and mercury mobilise under similar
conditions, thus a correlation between
these elements hints that a possible reloca-
tion has taken place. In Fig. 2, the mercury
concentration in the profile segments were
plotted against manganese, and the striking
lack of correlation suggest that the mercury
concentration in the various segments mir-
ror the original deposition of mercury on
top of a changing matrix of growing and
subsequently decomposing humus layer.
Mercury in vegetation
The Faroe Islands joined the European
Moss sampling Survey in 1995 and in 2000
(Riihling et al., 1996; 1998; Buse et al.,
2003). In this program, moss of the species
Hylocomium splendens is analysed for met-
als that may be emitted by local sources or
transported over longer distances by air
masses. The special feature of Hylocomium
s. of easily discernable segmented growth
is utilised by selecting for analyses only the
two to three outermost segments that corre-
sponds to the growth during the last two to
three years. Comparisons between results
of the 1995 and the 2000 study (Table 2)
indicate a decrease in lead and cadmium
from 1995 to 2000, whereas mercury was
analysed in the 2000 survey only so com-
parisons in time cannot be made.
In connection with the implementation
of the first phase of the Arctic Monitoring
and Assessment Programme, AMAP, in the
Faroes, moss of the species Racomitrium
and lichen of the species Cladonia sp. were
analysed (Larsen and Dam, 1999). It ap-
pears (Table 2) that the mercury concentra-
tions are higher in the Racomitríum and
Cladonia species than in Hylocomium s.
even when sampled in the same area. FIow-
ever, the sampling of the latter was done
three years later than the two first so com-
parisons must be made with regard to this.
It is well known that moss as an indicator
of metal ions in air and deposition is of lim-
ited use in areas where the air is full of lo-
cally produced metal ions from soil erosion
(Steinnes, 1995). In order to overcome the
dusting problem, the study includes analy-