International Journal of Marine Science, 2017, Vol.7, No.26, 260-271
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1.5 Geochemical Parameters
Oven dried (80°C) and powdered sediment samples were analysed for pH, total nitrogen (N) and organic carbon
(OC) (Maiti, 2003). Fe was detected with ICP-MS (Thermo).
2 Results and Discussion
2.1 THg content in the Fjord
The mean concentration of THg in the sediment was 485 ng/g dry weight (Table 2). The maximum concentration
was observed at the site 7 (1850 ng/g). The result of sediment mercury was discussed with respect to different
zones such as outer, middle, transitional and inner (Figure 2). Sediment from the middle zone showed higher
concentration of mercury followed by outer zone. The lowest content was noticed for transitional and inner zone
which is more influenced by the fresh water from surging glaciers. The middle and outer zone received glacial
water through small rivers which were fed with various glaciers, glaciated terrains, permafrost etc. and were
carrying high load of suspended matter. Lu et al. (2012) suggested that the high concentration may also be due to
the supply of mercury rich sediments from low and middle latitude to the Arctic by the West Spitsbergen Currents.
The mean concentration of THg in the sediments of Kongsfjorden was higher than that in any other Arctic region
(Table 3). The pattern of mercury contamination was same in the fjord and the sediment mercury content observed
during the year 2009 was 8-65 ng/g (Lu et al., 2012). Compared with the results of Lu et al. (2012), the Hg
concentration is higher in the present study. This might be due to the fine sediment fraction used in this study.
Unlike earlier study (Lu et al., 2012), the present study has shown high mercury content in the inner zone of
Kongsfjorden which is close to the port and glaciers. This can be owed to two things, one is the various activities
occurred in and around the the Ny-Alesund port and the other one is the deposition due to increased melting. This
can be an indicator for the influence of other sources like atmospheric mercury depletion events, glacial melting
etc. than the oceanic transportation.
Table 2 Hg concentration in the Kongsfjorden
Sample No.
Hg (ng/g)
1
101
2
178
3
1250
4
130
5
950
6
86
7
1850
8
107
9
125
10
034
11
1530
12
177
13
259
14
14
Mean
485
2.2 Mercury fractionation in the Kongsfjorden sediment
The percentage of various fractions of mercury obtained from the sequential extraction is given in the Figure 3.
The water soluble Hg fraction (F1) of Kongsfjorden sediments varied from 6.65% to 41.47% with a mean of
15.74%. The F2 fraction varied from 6.91% to 49.47% with a mean of 20.47%. The organic matter bound mercury
in the sediments of Kongsfjorden was varied from 4.43% - 84.72% where as the elemental mercury fraction (F4)
showed a high range of variation (2.4% to 93.74%). The mean contribution was 22.09% and 29.31% respectively
for F3 and F4 respectively. The fifth fraction, sulphide-bound mercury, was varied from 0.82% - 59.89%. The
mean value noticed for F5 was 12.38%. The average distribution of mercury in different chemical fractions
followed the order F4>F2>F1>F3>F5 (Figure 4).
