Comparison of the measured and calculated results of ~(137)Cs and ~(90)Sr concentration change in the Baltic Sea after Chernobyl Power Plant accident

摘要

The concentration data of artificial radionuclides in the Baltic Sea were averaged for the every year in the period of time 1986-2001. The averaged data consist of the measured results in the Baltic Sea proper, in the southeastern area and in the coastal waters. A slow decrease of the average concentration of ~(137)Cs in 1991-1995 and swift decrease in 1996 is defined. The measured and calculated average concentration of ~(137)Cs values were in a good agreement in 1997-1998 and in 2000. The discrepancy of mentioned results in another period of time is possible because of an extra radioactive contamination penetrating from the Bothnian Sea and the local effects. The discrepancy of measured and calculated results of average concentration of ~(90)Sr in the waters of the Baltic Sea is found out. The theoretic results show the tendency of the self-cleaning process of this radionuclide, however the measured data don’t indicate this tendency. The measured results are higher of the theoretic one in 1991-2000. The ratio of ~(137)Cs/~(90)Sr concentration changed in 1986-2000: the maximum number is 6.5 and minimum is 2.8. The slow self-cleaning of the Baltic Sea waters is possible because of the penetration an extra amount of artificial radionuclides.