Fróðskaparrit - 01.07.2004, Side 103

KYKSILVUR í FØROYUM - EIN GJØGNUMGONGD AV TØKUM DÁTUM
101
1992 1997 2000
Location LOI, % Hg, mg/kg LOI, % Hg, mg/kg LOI, % Hg, mg/kg
St 1 og 2 1992 7,3 0,085 SK 05 (1) (st 4) 9,8 0,11 9,0 0,089 0,033
SK 05 (2)** 8,4 0,104 8,3 0,043
SK 05 (3) 8,8 0,086
SK 07 (st 311) 12,6 0,11 10,7 0,111 12,6 0,058
SK 09 (st 31) 10,9 0,17 11,8 0,135 13,1 0,035
KA 05 9,1 0,037 9,4 0,031
KA 05 9,1
KA 09 7,6 0,033 10,0 0,020
KA 09 0,034
KO 07 6,6 0,034 6,8 0,028
SU 05 5,1 0,028 9,4 0,015
SU 15 6,8 0,035 9,3 0,018
SU 37 6,9 0,034
SU 41 6,4 0,024
FU 13 3,7 0,016
FU 17(1) 4,4 0,018
FU 17(2) 3,3 0,017
FU2I (1) 5,9 0,032
FU 21 (2) 6,8 0,025
FU 21 (3) 5,1 0,024
FU 21 (3) 0,024
** In 2000 analyses; the -2cm to -7 cm segment.
Table 7 Mercury, mg/kg dw, and Loss an ignition (LOl at 550°C) in %, itt sediments from some Faroese fjords in
1992, 1997 and 2000. Values are in tttg/kg dry weight when not otherwise is stated. Tlte sampling locations are
shown in Fig. 5. In some cases ttp to 3 replicates were collected from one location in 1997 and analysed
independently. Tltese are nttmbered 1 to 3 (in parenteses). Tlte mercury analysis on sample FU21 (3) 1997 was
done in duplicate. Tlte analyses were done on the 0-2 cm segment of the sediment core. Adapted from Gregersen
et al„ 2000 and Mikkelsen et al. 2002.
tion reaching 0,17 mg/kg at one station in
1992. Plotting the concentration of mer-
cury as a function of the LOI (Fig. 4) re-
veals that the elevated concentrations in the
Skálafjord sediments are not in line with
the concentrations in the other fjords even
when elevated organic material content is
taken into consideration. This is an indica-
tion that the mercury concentration in the
Skálafjørðinum in 1992 and 1997 was ele-
vated above the natural background.
Comparing the results of the two (three)
years indicate that overall the mercury con-
centration is either stable or decreasing. In
Skálafjord, the median of mercury concen-
tration in the upper sediment layer in the
threeyears 1992, 1997 and2000 were0,ll
mg/kg, 0,10 mg/kg and 0,04 mg/kg respec-
tively, with the largest decreases occurring
at station SK09 (Fig. 5) in going from 0,17
mg/kg in 1992 (the station was then called
St.3 I) to 0,14 mg/kg in 1997 and ending at
0,04 mg/kg in 2000.