25
Appendix
An Intercomparison of Radionuclide Analyses in a Baltic Sea Sediment Sample
Results of the HELCOM MORS-PRO intercomparison
on Baltic Sea Sediment 2000
Tarja K. Ikaheimonen and Vesa-Pekka Vartti
STUK - Radiation and Nuclear Safety Authority
Helsinki, Finland
Introduction
As a part of the HELCOM MORS-PRO work, the
MORS Group arranged an intercomparison exercise
of radionuclide analyses using a sediment
sample taken from the Baltic Sea. The sediment
sample was taken by STUK on 21 June 1999
at the Station EB1 in the Bothnian Sea (latitude
61°04.00’ N, longitude 19°43.78’ E, at a depth
of 130 m). The sampling was carried out with an
Aquarius Box Corer (surface area of 18 cm x 18
cm). Fourteen parallel sediment cores were taken
to achieve the target amount of 60 kg wet weight.
The top layer (0-10 cm) of each core was sliced
and used for the exercise. The material was sent
to IAEA-MEL, which contracted with EUROLYO
Ltd. for the freeze-drying and homogenization of
the sample.
Aliquots of the homogenized sediment sample,
Baltic Sea Sediment 2000, were delivered to the
MORS Group in June 2000. Gamma-emitting
nuclides, natural radionuclides, and transuranic
elements were requested to be analysed.
Participants
Altogether eight laboratories from Denmark,
Estonia, Finland, Germany, Latvia, Poland, and
Sweden participated in the intercomparison as
listed in Table A1.
Analytical results
All laboratories analysed the sediment sample
for K-40 and Cs-137. Nine other gamma-emitting
nuclides were also analysed, and of these, Cs-134,
Pb-210, Ra-226, Th-228, Th-232, U-238, and
Co-60 were analysed by more than one labora-Laboratory
Country
Code
Rise National Laboratory, Roskilde
Denmark
RISO/DK
Estonian Radiation Protection Centre, Tallinn
Estonia
ERPC/ES
STUK - Radiation and Nuclear Safety Authority, Helsinki
Finland
STUK/FI
Federal Maritime and Hydrographic Agency, Hamburg
Germany
DHIG/GE
Federal Research Centre for Fisheries Institute of Fisheries Ecology, Hamburg
Germany
BFFG/GE
Ministry of Environmental Protection and Regional Development of Latvia, Riga
Latvia
LVEA/LV
Central Laboratory for Radiological Protection, Warsaw
Poland
CLOR/PO
Swedish Radiation Protection Institute, Stockholm
Sweden
SSI/SW
Table A1.
Laboratories participating
in the
intercomparison
exercise.
Lab.code
K-40
Uncert.
Cs-137
Uncert.
Cs-134
Uncert.
RISO/DK
998
100
1020
102
9.2
1.0
ERPC/ES
1100
80
1220
53
9.2
0.9
STUK/FI
980
59
1060
53
9.8
1.0
DHIG/GE
991
8.4
1140
5.82
9.97
0.47
BFFG/GE
1000
24
1100
27
9.95
0.28
LVEA/LV
795
24
988
20
9.30
1.58
CLOR/PO
1050
48
1060
21
-
-
SSI/SW
1130
17
1200
20
11.9
1.9
Mean
1006
101
1098
82
9.9
0.94
Table A2.
Results for artificial
gamma-emitting
radionuclides in
Bq kg -1 d.w. with
an uncertainty of
1 sigma and the
arithmetic means
with the standard
deviation (in the
Uncert. column).
Long-lived radionuclides in the seabed of the Baltic Sea
