2.4. Transport of 137Cs in Large Finnish Drainage Basins

摘要: Summary Area-specific transfer parameters are useful in predicting internal radiation doses incurred via the consumption of fish or drinking fresh water, as well for estimation counter-measures which might be needed an accidental release radionuclides. The results obtained from countrywide studies Finnish Centre Radiation and Nuclear Safety, carried out aquatic environment after 1986, were used to compare 137 Cs seven large drainage areas Finland. During first six months accident at Chernobyl, correlation between area concentrations water deposition was linear, also median contents basins concerned Cs. In subsequent years, temporal changes more profoundly affected by character catchment area. Though differences amount runoff taken into account, still existed areas. Annual factors highest basin characterized bog lowest clay coastal with a low percentage lakes, somewhat lower than inland higher lake percentages. decrease had least two components all studied. At decreased rapidly effective ecological halflife 0.15 - 0.36 except abundant bogs where remarkably slower 0.94 years. began different times halflives next phase varied 1.2 2.8 second third year annual maximum predatory it about 0.4 m 2 /kg, whereas other 0.2 /kg. observed half-life beginning decline 0.7 years differing most others, 3 5 deposited 1986 almost totally retained only little, 1 2%, removed rivers flowing sea five deposition.