The data and resulting data products (tables, figures and maps) available on the indicator web pages can be used freely given that the source is cited. The indicator should be cited as following:
HELCOM (2018) Radioactive substances: Cesium-137 in fish and surface water. HELCOM core indicator report. Online. [Date Viewed], [Web link].
Result: Radioactive substances: Cesium-137 in seawater
Data: Radioactive substance s: Cesium-137 seawater data
Result: Radioactive substances: Cesium-137 in herring
Result: Radioactive substances: Cesium-137 in flatfish
Data: Radioactive substances: Cesium-137 in fish data
Data source: HELCOM MORS Database.
Description of data: Herring and seawater data cover most of the Baltic Sea, but flatfish covers only southern parts of the Baltic Sea. For time series maps, data from the year 2012 were used. The data are based on 137Cs concentrations in a) herring (Clupea harengus L.), b) flounder (Platichthys flesus L.) and plaice (Pleuronectes platessa L.) and c) surface seawater (samples 0–10 m). Analyses have been done either in round fish (without head and entrails) or filets (herring), and for plaice and flounder from filets only. Concentrations (Bq kg-1) have been calculated per wet weight of the samples. Seawater concentrations (Bq m-3) have been analyzed in surface (0–10 m) water samples. Data of each matrix (herring, plaice and flounder and sea water) have been averaged by sub-basin and by year.
The data is collected by national authorities and reported annually to the HELCOM MORS Database. In addition to national quality assurance procedures, manual quality assurance is applied to the reported data and data entries are verified annually by the HELCOM MORS Expert Group.