1994 Arctic Ocean Section
in shelf regions, are transported down
into the halocline, intermediate and
deep water layers of the Arctic Ocean.
Particle reactive isotopes can also be
transported into the interior of the
Arctic Ocean through incorporation
EfflEfelnentrfoom Russiaan
u f ut F r m Russi n
PrococesisingPllantts
Pres sng P a s
into ice and subsequent release of the
ice-rafted radioactive contaminants
Russian Nuulclarar
Russian Nc e e
into the water column and sediments
TesttSitiees
T s S ts
by melting or breakup of the ice.
Until recently, studies of the trans-
RussisianRadioactitvve
Rusan Radioac ie
DDumpsite
um ps e
port of artificial radioactivity into the
Arctic Ocean had been limited to
Effluent tFrom thhe
Effluen from t e
measurements conducted from a few
SSellaffiield
el la d
Proceessiing Pllant
Procss n Pant
ice stations, such as LOREX (1979),
Atlanaintic WaeerFlow
Atlt c Wat t r F w
FRAM3 (1981), CESAR (1983), AI-
WEX (1985) and the Canadian Ice
Island (19851989). The use of ice-
breakers during AOS-94 has vastly increased the number of sampling loca-
Sources of artificial
radionuclides in the
tions in the western Arctic Ocean. Water samples were collected from many of
Arctic Ocean.
the major areas of the Arctic Ocean, including the Chukchi Sea and the Can-
ada, Makarov, Amundsen and Nansen Basins. Sediment cores were collected
in areas of sediment accumulation along the cruise track.
The levels of artificial radionuclides in Arctic Ocean water are low and
require concentration from large volumes of water in order to measure the
levels by conventional counting techniques. Samples were collected either by
combining several Niskin bottle samples from the rosette sampler or by using
pumps to pass water through resins and absorbers that remove and concen-
KCFC (potassium cobalt ferrocyanide) resin. Strontium, plutonium and ameri-
to 100 L by precipitation, and the concentrates were returned to the labora-
tory for further purification and counting. Sediment cores were subsampled
and analyzed at 1-cm intervals. Sediment analyses are being used to calculate
sediment inventories of artificial radionuclides and to identify areas of net
accumulation.
Preliminary measurements for 137Cs and 129I clearly show the presence of
Sellafield and Chernobyl contaminants in surface and Atlantic-layer water
throughout the Arctic Ocean. The main exception was surface water in the
Chukchi Sea, where Pacific-origin water, containing only atmospheric fallout,
flows in through the Bering Strait. The highest activities (1215 Bq/m3 for
137Cs and 80100 107 atoms/L for 129I) were found over the Lomonosov
Ridge near the North Pole, consistent with the surface circulation pattern of
60
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