11:30 AM - 11:45 AM
[MAG33-09] Initial declining trend of the activity concentration of 137Cs of river sediment in Fukushima area
Keywords:Cs-137, river sediment, environmental recovary
Any large fluctuation of activity concentration in river sediment can be seen after the grain size correction. In addition, the point where concentration increased with time decreased from 25 points to 7 points. The rate of decline (λ) in the 89 sediments in the sediment has an average of 1.15, and it was possible to elucidate the tendency of the concentration of the river sediment to decrease. In addition, when we set the standard sample size of the suspeneded sediment, the activity concentration of the bottom sediment may be used to estimate the suspended sediment activity concentration. After the grain size correction to suspended sediment, activity concentration of SS and rate of decline agreed at 14 points out of 24 points. From this results, suspended sediment and dissolved state are in equilibrium state at many points due to adsorption/ desorption when cesium flows down the river.