Summary of survey

  1. The analysis results show radiation (Bq) per unit weight (kg).
  2. When selecting locations to collect well water samples from, it was taken into consideration as the selection criteria that 1) the location should have a relatively high accumulated radioactive cesium based on the results of the land-based monitoring and airborne monitoring surveys, and 2) the wells should have covers to prevent radioactive substances from coming in from outside in order to check the movement of radioactive substances into wells via groundwater. Based on these criteria, 51 locations were chosen.
  3. In order to confirm the changing trend of the concentrations of radioactive substances in the well water, we conducted samplings twice within the period between June and October.
  4. The radioactivity concentration measurement procedures
    • 134Cs, 137Cs and 131I
      All samples were measured
    • 89Sr and 90Sr
      Because of the long measurement time required, sampling points where detection of these nuclides were expected were chosen (6 points)
  5. Regarding radioactivity concentration, error and detection limit, 89Sr and 90Sr decay-compensated values from measurement to sampling. Values of other nuclides are at time of measurement.
  6. "ND" in the column "Deposition", "-" in the column "Error", and detection limit value as reference in the column "detection limit": The peak of relevant nuclide was not clearly detected or calculated deposition was equal to or below 0.0.
  7. Reference value in the column "Deposition" smaller than the detection limit in the column "detection limit": The peak of the relevant nuclide was detected even though the calculated deposition was below detection limit.
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