During the project, an intense monitoring was carried out to measure the
present levels of artificial radioactivity in the Arctic Seas.The measurements
can be separated into two categories:
Tracing of Sellafield derived radionuclides during cruise 261 with R/V GAUSS
to the North Sea, Norwegian Sea, Barents Sea and Greenland Sea from 15 June
to 27 July 1995;
Analyses of sediment and water samples taken in the Kara sea and near the
Kola peninsula, in order to trace any potential releases or pollution originating
from dumped wastes.
The cruise track of R/V GAUSS followed the well-known transport pattern of
contaminated water from the North Sea to Arctic areas. The Water samples
taken in the North Sea showed varying 137Cs activities between 3.1 and 25.5
Bq/m3. The maximum concentrations above 20 Bq/m3 are located in the Skagerrak
due to the continuous outflow from the Baltic Sea. Nevertheless, the dominant
source of radioactivity in the North Sea are the discharges at Sellafield
reprocessing plant (UK) into the Irish Sea. The present "background"
concentration of surface water in the northern hemisphere originating from
the global weapon test fallout is estimated to be between 2 and 3 Bq/m3.
The observed concentrations in the Greenland Sea, Norwegian Sea and Barents
Sea are in this range. Water samples near the Norwegian coast show slightly
enhanced activity up to 8.6 Bq/m3 decreasing in northern direction reflecting
the water mass transport from the North Sea into the Arctic. Samples taken
near the wreck of the 'Komsomolets' show no sign of contamination from the
reactor. Some higher, but not alarming activities are found in coastal waters
of the Murmansk region (8 Bq/m3), where the largest part of the russian nuclear
fleet is situated. The values suggest some smaller release of radioactivity
from nuclear facilities.
In short, historically and currently the reprocessing plant of Sellafield
is the most important source for radioactivity in the observed areas. Maximum
releases from Sellafield occurred in 1975 and have significantly been reduced
since that time. At the Moment, these results conclude that there is no danger
to the ecosystem or to people indirectly through fish consumption. Significant
outflow of radioactivity from dumped objects that may affect the Kara sea
has not been observed.
1 Bq = 1 Becquerel = 1 decay per second