DEPOSITION MEASUREMENTS IN EUROPE AFTER THE CHERNOBYL ACCIDENT AND COMPARISON WITH THE GREEK "NTUA DATA SET"

Fission product deposition data, from the Chernobyl reactor accident, have been compiled by the Commission of the European Communities and put together as part of the Radioactivity Environmental Monitoring (REM) programme. Most of these data originate from surface soil sampling and analysis for longer-lived activity with emphasis to that due to Cs-137. According to this compilation, of 3233 data, 1460 of which come from the Greek NTUA soil sampling programme, the Cs-137 cumulative deposition ranges between 261 to less than 1 kBq/m2, while the ratio Cs-134/Cs-137 is always close to 0.5. The data provided by the Greek NTUA soil sampling programme, which is considered by the CEC as "intensive and systematic", show that the mean value of the Cs-137 deposition in Greece (7.3 kBq/m² - 1242 samples) was not as high as mean values of subregions of other EC countries, such as Southern Germany (14 kBq/m² - 98 samples) and Northern Italy (15 kBq/m² - 29 samples). The maximum observed cumulative deposition of Cs-137 is 149 kBq/m² detected near the city of Karditsa in Central Greece. The high resolution gamma spectrographic analysis of the above data set, provides also information about other longer-lived fission products in the fallout, the most important of which is Ru-103 with maximun observed cumulative deposition 337 kBq/m² detected near the city of Naoussa, in Northern Greece.