Abstract
The uptake and accumulation of cesium-137 by fishes from sea water was studied through the field studies for eight years (1963-1970). The concentrations of cesium-137 in marine fish muscles have decreased with time since 1963, and the concentration factors ranged from 11 to 81. On the other hand, the concentration factors of stable cesium remained in a narrow range between 34 and 52. The mean value of the observed ratio (OR) calculated by cesium-137 and potassium was 5.7 during the period from 1964 to 1970, and the OR value based on stable cesium was 5.9. The ratios between annual mean values of the specific activities of fish muscles and of sea water were found to be from 0.6 to 1.5.
From these data, if the concentration of cesium-137 in the environmental sea water is known, it is possible to estimate the approximate concentrations of cesium-137 in marine fishes by using the concentration factor or observed ratio without any analytical procedures.
