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Radioactivity and Air Dose Rate


How much radiocesium migrates in environment?

Stock and flow of 137Cs in the Ukedo River catchment was estimated.

  • The ratio of outflow to inflow for the reservoir is around 0.1, which is consistent with the measurement.
  • The flux from river to adjacent sea is around 0.2 TBq/y, which is good agreement with the field monitoring (0.23 TBq/y).
  • Most radiocesium flows through the adjacent sea. The sedimentation flux used in the simulation (based on Otosaka et al. and Buesseler et al.) should have been too small. Also Kd should have been too large.

Fig.1 Ukedo River basin (around Ogaki dam) map

The Takase River is excluded.

Fig.2 Stock flow of radioactive cesium 5 years after fallout in the Ukedo River basin
*The Takase River is excluded.

Black digit: Inventory [Bq]
Red digit: Flux [Bq/y]
positive for the direction to water compartments