Fróðskaparrit - 01.07.2004, Side 99

KYKSILVUR í FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
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Fig. 3 Mercury correctedfor the organic
content in dated segments of sediment core from
Sørvágsvatni (Olsen et al.2003).
pressed as loss on ignition, LOI, gives more
equal concentrations, of approx. 0,4 and
0,33 pg Hg/g org. material in Sørvágsvatn
and Leynavatn respectively.
The results (Fig. 3 and Table 4) indicate
that the mercury concentration has doubled
during the last 200 years up to a maximum
occurring approx. 60 years ago, after which
time it appears to decline again. Because of
the distance between the points (i.e. the
thickness of the slices) the profile is rather
uncertain, and the analyses should be re-
peated with higher resolution in time.
Information on water chemistry in Sør-
Sørvágsvatn Leynavatn
Sedimentation rate 0,12 0,2*
Segment depth Age Hg LOI Age Hg LOI
cm years ug/kg dw g/kg dw years ug/kg dw g/kg dw
0-2 -16,7 91,3 245 33,9 129
2-7 -58,3 104 214 38 105
7-12 -100,0 95,3 232 40,2 102
12-17 -141,7 85,7 273 45,3 116
17-22 -183,3 90,3 296 -110,0 46,8 142
22-26 -216,7 56,9 322 -120,0 37,1 99,8
* This value applies only to two slices at the bottom of the sediment core.
Table 4 Age, mercury concentration and loss on ignition (LOI) in segments of sediment cores from Sørvágsvatn
and Leynavatni (Olsen et al„ 2003).