Radioactive substances:

Caesium-137 (137Cs) in fish and surface waters

Authors

HELCOM Monitoring of Radioactive Substances Expert Group

Corresponding authors:

Marc-Oliver Aust - Thünen Institute of Fisheries Ecology, Germany

Iisa Outola – STUK - Radiation and Nuclear Safety Authority, Finland

Tamara Zalewska - Institute of Meteorology and Water Management – National Research Institute, Maritime Branch, Poland

1. The radionuclide cesium (137Cs) is the greatest contributor to the level of artificial

radionuclides in the Baltic Sea, where the level of 137Cs contamination is still higher than in any other of the world oceans

2. The main source of 137Cs deposited in the Baltic Sea is the accident at the Chernobyl nuclear power plant in 1986

3. 137Cs is bioccumulated in marine flora and fauna and it is deposited in the marine sediments. Therefore 137Cs activity concentrations are the key factors in an assessment of the radiological hazard to marine organisms and humans

4. Ingestion of 137Cs with fish is the dominating exposure pathway of humans to man-made radioactivity in the Baltic Sea. Therefore, 137Cs concentrations in herring and flatfish are well suited as indicators for man-made radioactivity in the Baltic Sea. Internationally recommended maximal permitted concentrations of 137Cs in foodstuff are in the range 100–1250 Bq/kg (EU, 2012 and EC, 2010)

5. The development and use of nuclear power for military and peaceful purposes have resulted in the production of a number of man-made radioactive substances and their release into the environment. Even the routine operations of nuclear power plants cause small controlled discharges of radioactive substances, but accidents at nuclear power plants can release considerable amounts of radioactivity into the environment. Artificial radionuclides of particular concern to man and the environment are 90Sr and 137Cs, both are formed by nuclear fission. For these reasons, it is necessary to control the concentration levels of radionuclides - 137Cs

Caesium-137 (137Cs) in fish and surface waters

concept of the indicator

Caesium-137 (137Cs) in fish and surface waters

Stage of development Indicator type

Core/pre-core/candidate State/Pressure/Impact

Primary importance Secondary importance

BSAP

Segment and Objective • Hazardous substances segment

• Radioactivity at pre-Chernobyl level

MSFD

Descriptors and Criteria 8 Concentrations of contaminants are at

levels not giving rise to pollution effects

8.1. Concentration of contaminants

9 Contaminants in fish and other seafood

for human consumption do not exceed

levels established by Community

legislation or other relevant standards.

9.1. Levels, number and frequency of

contaminants

Other relevant legislation: (e.g. WFD)

The work of HELCOM MORS Expert Group also supports the implementation of the Euratom Treaty, of

which all EU Member States are signatories. The Euratom Treaty requires actions in relation to

monitoring and controling effects of discharges on neighboring states.

Legislative linkage:

Caesium-137 (137Cs) in fish and surface waters

Concept/ design

Coordinated monitoring Assessment

Research needs for operationalization (in

relation to needs stated under the coordinated

monitoring and assessment columns)

Data arrangements

Monitoring strategy (method, frequency, spatial resolution) in relation to relevant indicator parameters Technical guidelines Geographic scale

Assessment method

GES / assessment criteria (currently all GES are provisional)

A ) in place B) under development C ) not available, what needs - action level?

A ) monitoring in place B ) monitoring needs revision C ) monitoring not available, what needs - action level?

A ) in place B ) needs revision, what needs doing C ) not available, what needs - action level?

HELCOM assessment units: A ) identified B) Identified not described C) not identified, what needs - action level?

A ) available and described B ) available not described C ) not available, what needs - action level?

A ) proposed and described B ) proposed but needs more supporting data C ) not available, what needs - action level?

A ) in place B ) needs revision, what needs doing C ) not available, what needs - action level?

A

Concept

In place

A

Monitoring in

place

A

Technical

guidelines

in place

A

HELCOM

assessment

unit identified

A

Assessment

method –

established

A

GES/

assessment

criteria

proposed

and described

A

Data

arrangements

in place

Caesium-137 (137Cs) in fish and surface waters

• Target setting for 137Cs: Today, no internationally accepted criteria for the assessment of GES in

fish exist. There are only upper levels available in the literature, where fish will suffer from doses

of radioactive substances (e. g. ICRP, 2008). Therefore, target values for 137Cs concentrations in

sea water and biota have been set at pre-Chernobyl levels. These are 2.5 Bq kg-1 for herring,

2.9 Bq kg-1 for flounder and plaice and 15 Bq m-3 for seawater. The average values have been

obtained from HELCOM MORS Database 1984-1985 measurements.

• Confidence of target: High. The confidence is considered high as there are numerous

observations from pre-Chernobyl time even if the length of this time series is short (1984-1985).

HELCOM Expert Group on Monitoring of Radioactive Substances in the Baltic Sea

• Sven P. Nielsen – Danmark

• Eia Jakobson – Estonia

• Tarja Ikäheimonen – Finland

• Iisa Outola – Finland

• Jürgen Herrmann – Germany

• Günter Kanisch – Germany

• Marc – Oliver Aust – Germany

• Beata Vilimaite-Silobritiene – Lithuania

• Maria Suplińska – Poland

• Tamara Zalewska – Poland

• Andrey Stepanov – Russia

• Maria Lüning – Sweden

• Iolanda Osvath – International Atomic Energy Agency, Environment Laboratory, Monaco

• Vesa-Pekka Vartti – Finland

Caesium-137 (137Cs) in fish and surface waters

• HELCOM Assessment Unit Level: 2

• The indicator is applicable in: all subbasins around the Baltic Sea

• Currently data is available:

List of issues that still need

to be solved for the

indicator

Describe what is hindering solving the issue

e.g. Low confidence in the result Funding for data collection and analysis is still unsecure and the amount of data needed

for the analysis has not yet been met.

- -

Caesium-137 (137Cs) in fish and surface waters

Caesium-137 (137Cs) in fish and surface waters

Seawater Fish

Caesium-137 (137Cs) in fish and surface waters

Liquid discharges of radioactive substances

Liquid discharges of Cs-137, Sr-90 and Co-60 into the Baltic Sea from local nuclear installations Baltic Sea Environment Fact Sheet 2013

Author: Vesa-Pekka Vartti, STUK - Radiation and Nuclear Safety Authority, Finland

Year Loviisa Olkiluoto Greifswald Sosnovyi Bor

(Leningrad) Forsmark Studsvik

Oskarsham

n Barsebäck Ringhals

1984 9,30E+09 2,30E+06 1,13E+09 3,70E+08 1,50E+11 8,62E+09 9,23E+09 6,15E+09

1985 7,00E+09 1,20E+09 4,40E+09 8,60E+10 3,20E+09 1,80E+09 3,40E+09

1986 1,00E+10 8,80E+08 1,80E+09 4,00E+09 3,30E+10 9,90E+09 5,00E+09 1,50E+10

1987 4,60E+09 4,20E+08 1,84E+09 5,60E+09 3,30E+10 2,10E+09 8,50E+07 7,70E+09

Table 1.

Annual caesium-137 discharges from different installations in 1984-2012 [Bq].

2008 6,62E+06 3,61E+07 9,80E+06 9,66E+06 1,23E+09 1,22E+08 4,00E+07 2,49E+08

2009 5,79E+08 3,13E+07 3,21E+06 2,14E+07 7,31E+08 1,40E+08 6,68E+07 2,27E+08

2010 1,44E+07 3,05E+07 3,60E+05 6,75E+05 1,84E+07 7,65E+08 6,81E+07 2,36E+07 2,99E+08

2011 8,89E+06 3,07E+07 2,20E+05 1,71E+07 4,84E+08 5,54E+07 1,07E+08 3,52E+07

2012 1,11E+07 1,93E+07 1,47E+07 4,43E+08 8,46E+07 1,06E+08 6,18E+07